JP7525991B2 - Method for producing surface-modified metal oxide fine particles, method for producing modified metal oxide fine particles, surface-modified metal oxide fine particles, and metal oxide fine particle dispersion liquid - Google Patents

Description

The present invention relates to a method for producing surface-modified metal oxide microparticles, a method for producing modified metal oxide microparticles suitable as a method for producing metal oxide microparticles that are the subject of surface modification in the production of the above-mentioned surface-modified metal oxide microparticles, surface-modified metal oxide microparticles, and a metal oxide microparticle dispersion liquid containing the above-mentioned surface-modified metal oxide microparticles.

Metal oxide fine particles are widely used as materials for processing various articles such as optical materials, electronic component materials, and abrasives. Such metal oxide fine particles are often used as a dispersion liquid because they are easy to transport, measure, and handle. However, when untreated metal oxide fine particles are dispersed in a dispersion medium such as an organic solvent, there is a problem that the metal oxide fine particles tend to aggregate. If the metal oxide fine particles aggregate in the dispersion medium, the metal oxide fine particles are less likely to exhibit their functions. For this reason, a method for surface treatment of metal oxide fine particles has been proposed to impart good dispersion stability to the metal oxide fine particles in a dispersion medium such as an organic solvent.

As such a surface treatment method, a method has been proposed in which at least a portion of the surface of metal oxide fine particles is coated with a carboxylic acid compound having an aromatic structure (Patent Document 1).

JP 2015-017026 A

However, there was room for further improvement in the dispersion stability of metal oxide microparticles surface-treated by the method described in Patent Document 1. In addition, metal oxide microparticles surface-treated by the method described in Patent Document 1 were prone to aggregation depending on the types of components contained in the dispersion liquid.

The present invention has been made in consideration of the above problems, and aims to provide a method for producing surface-modified metal oxide microparticles that can produce surface-modified metal oxide microparticles that have excellent dispersion stability in dispersions of various compositions, a method for producing metal oxide microparticles that is suitable as a method for producing modified metal oxide microparticles that are the subject of surface modification in the production of the above-mentioned surface-modified metal oxide microparticles, surface-modified metal oxide microparticles that can be produced by the above-mentioned method, and a metal oxide microparticle dispersion containing the above-mentioned surface-modified metal oxide microparticles.

The present inventors have discovered that the above-mentioned problems can be solved by producing surface-modified metal oxide fine particles by a method that includes coating at least a portion of the surface of the metal oxide fine particles with a carboxylic acid compound and/or its carboxylate having a specific structure substituted with an amino group, which may be cyclic, and have thus completed the present invention. Specifically, the present invention provides the following.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子、又は１価の有機基であり、Ｒ^１とＲ^２とが互いに結合して環を形成してもよく、前記環は、環構成元素としてＮ、Ｓ、及びＯからなる群より選択される元素を１つ以上含んでいてもよく、Ｒ^３は、１価の有機基であり、Ｒ^４は、メチレン基、又は単結合である。）
で表されるカルボン酸化合物及び／又は式（１）で表されるカルボン酸化合物由来のカルボキシレートで被覆することを含む、表面修飾金属酸化物微粒子の製造方法である。 In a first aspect of the present invention, at least a part of the surface of a metal oxide fine particle is represented by the following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a hydrogen atom or a monovalent organic group, ^R1 and ^R2 may be bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1).

A second aspect of the present invention is a method for producing modified metal oxide microparticles, which comprises preparing metal oxide microparticles in a solution or suspension containing a compound having an amide structure, or dispersing metal oxide microparticles in the presence of a dispersion medium containing a compound having an amide structure.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子、又は１価の有機基であり、Ｒ^１とＲ^２とが互いに結合して環を形成してもよく、前記環は、環構成元素としてＮ、Ｓ、及びＯからなる群より選択される元素を１つ以上含んでいてもよく、Ｒ^３は、１価の有機基であり、Ｒ^４は、メチレン基、又は単結合である。）
で表されるカルボン酸化合物及び／又は式（１）で表されるカルボン酸化合物由来のカルボキシレートで被覆された、表面修飾金属酸化物微粒子である。 In a third aspect of the present invention, at least a part of the surface is represented by the following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a hydrogen atom or a monovalent organic group, ^R1 and ^R2 may be bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1).

The fourth aspect of the present invention is a metal oxide fine particle dispersion liquid containing the surface-modified metal oxide fine particles according to the third aspect as the metal oxide (A).

The present invention provides a method for producing surface-modified metal oxide microparticles that can produce surface-modified metal oxide microparticles that have excellent dispersion stability in a dispersion liquid, a method for producing modified metal oxide microparticles that are suitable as a method for producing metal oxide microparticles that are the subject of surface modification in the production of the above-mentioned surface-modified metal oxide microparticles, surface-modified metal oxide microparticles that can be produced by the above-mentioned method, and a metal oxide microparticle dispersion liquid containing the above-mentioned surface-modified metal oxide microparticles.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子、又は１価の有機基であり、Ｒ^１とＲ^２とが互いに結合して環を形成してもよく、前記環は、環構成元素としてＮ、Ｓ、及びＯからなる群より選択される元素を１つ以上含んでいてもよく、Ｒ^３は、１価の有機基であり、Ｒ^４は、メチレン基、又は単結合である。）
で表されるカルボン酸化合物及び／又は式（１）で表されるカルボン酸化合物由来のカルボキシレートで被覆することを含む、方法である。 <Method for producing surface-modified metal oxide fine particles>
The method for producing surface-modified metal oxide fine particles includes the steps of:
At least a part of the surface of the metal oxide fine particles is treated with the following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a hydrogen atom or a monovalent organic group, ^R1 and ^R2 may be bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1).

The carboxylate is a carboxylate anion derived from a carboxylic acid compound represented by formula (1) that can be bonded to or attached to the surface of metal oxide fine particles, or a salt of a carboxylic acid compound represented by formula (1). The bond or attachment to the surface of metal oxide fine particles can be confirmed, for example, by an X-ray photoelectron spectroscopy (XPS) or the like.
In the salt of the carboxylic acid compound represented by formula (1), the counter cation for the carboxylate anion may be an inorganic cation or an organic cation, preferably an inorganic cation. The counter cation may be a monovalent cation or a polyvalent cation having a valence of two or more.

The inorganic cation is not particularly limited, but is preferably an alkali metal cation such as a sodium ion or a potassium ion, or a cation derived from a metal element contained in the metal oxide fine particles.
Preferred metal elements that can be contained in the metal oxide fine particles will be described later.

The surface-modified metal oxide fine particles coated with the carboxylic acid compound represented by formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by formula (1) produced by the above method exhibit good dispersion stability in various liquids. The surface-modified metal oxide fine particles produced by the above method are stably dispersed in a dispersion liquid regardless of the composition of the dispersion liquid, and in particular, exhibit good dispersion stability even in a liquid containing a compound having an aromatic ring such as a fluorene skeleton.

<Metal oxide fine particles>
As the metal oxide fine particles, various metal oxide fine particles that have been used for various purposes can be used without any particular limitation. For example, metal oxides such as _ZrO2 fine particles are used in high refractive index materials. It is used as a filler to achieve a high refractive index.

The shape of the metal oxide microparticles is not particularly limited. Examples of the shape of the metal oxide microparticles include spherical, granular, elliptical, cubic, rectangular, pyramidal, needle-like, columnar, rod-like, cylindrical, scale-like, plate-like, and thin flake-like shapes, with spherical, granular, columnar, and other shapes being preferred.

The type of metal oxide constituting the metal oxide fine particles is not particularly limited as long as it does not impair the object of the present invention. The metal oxide fine particles may be fine particles made of a single metal oxide, or may be fine particles made of two or more metal oxides.
In the coating treatment with the carboxylic acid compound represented by formula (1) or the like, one type of metal oxide fine particles may be used alone, or two or more types of metal oxide fine particles may be used in combination.

As the metal constituting the metal oxide fine particles, for example, at least one selected from the group consisting of Ag, Cu, In, Sn, Ti, Hf, Al, Zr, Zn, Sn, and Ce is preferable. From the viewpoint of being able to provide a metal oxide with a high refractive index, among the above metal elements, at least one selected from the group consisting of Ti, Al, Zr, Zn, Sn, and Ce is preferable, and Zr is particularly preferable.
Suitable examples of metal oxides constituting the metal oxide microparticles include _{single metal oxides such as aluminum oxide (Al2O3 )} , titanium oxide ( _TiO2 ), hafnium oxide ( _HfO2 ), zirconium oxide ( _ZrO2 ), _{indium oxide (In2O3 ) ,} zinc oxide (ZnO), tin oxide ( _SnO2 ), lanthanum oxide ( _La2O3 ), yttrium oxide ( _Y2O3 ), cerium oxide ( _CeO2 ), and magnesium oxide ( _MgO ) _; solid solutions of metal oxides such as ITO and ATO; and composite metal oxides such as barium titanate ( _BaTiO3 ), perovskite ( _CaTiO3 ), and spinel ( _MgAl2O4 ).

The average particle size of the metal oxide fine particles is not particularly limited as long as it does not impair the object of the present invention. The average particle size of the metal oxide fine particles is, for example, preferably 50 nm or less, more preferably 20 nm or less, even more preferably 10 nm or less, and particularly preferably 5 nm or less. The lower limit of the average particle size of the metal oxide fine particles is, for example, 1 nm or more, and may be 2 nm or more.
The average particle size of the metal oxide fine particles is a volume average particle size measured by dynamic light scattering.
In terms of increasing the refractive index, the particle size at a cumulative value of 99.99% in the cumulative particle size volume distribution of the metal oxide fine particles is preferably, for example, 50 nm or less, more preferably 30 nm or less, and even more preferably 20 nm or less. There is no particular lower limit, but it is, for example, 5 nm or more. The particle size distribution (cumulative particle size volume distribution) of the metal oxide fine particles is also measured using a dynamic light scattering method.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に水素原子、又は１価の有機基であり、Ｒ^１とＲ^２とが互いに結合して環を形成してもよく、前記環は、環構成元素としてＮ、Ｓ、及びＯからなる群より選択される元素を１つ以上含んでいてもよく、Ｒ^３は、１価の有機基であり、Ｒ^４は、メチレン基、又は単結合である。） <Carboxylic Acid Compound>
For coating the surfaces of the above-mentioned metal oxide fine particles, a carboxylic acid compound represented by the following formula (1) and/or a carboxylate derived from the carboxylic acid compound represented by the formula (1) is used.
In addition, when the carboxylic acid compound represented by formula (1) or the carboxylate derived from the carboxylic acid compound has two or more optical isomers, any of the optical isomers can be used to coat the surface of the metal oxide fine particles. Also, a mixture of the optical isomers can be used to coat the surface of the metal oxide fine particles.

(In formula (1), ^R1 and ^R2 are each independently a hydrogen atom or a monovalent organic group, ^R1 and ^R2 may be bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)

For the sake of convenience, only the carboxylic acid compound represented by formula (1) will be described below, but carboxylates derived from the carboxylic acid compound represented by formula (1) can also be used for coating in the same way as the carboxylic acid compound represented by formula (1).

In formula (1), R ¹ and R ² are each independently a hydrogen atom or a monovalent organic group. The monovalent organic group is not particularly limited. The monovalent organic group may be, for example, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, an aralkyl group that may have a substituent, an aliphatic heterocyclic group that may have a substituent, and an aromatic group that may have a substituent.
When ^R1 and ^R2 are monovalent organic groups, the organic group preferably has 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, even more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms.
In addition, R ¹ and R ² may be bonded to each other to form a ring.

It is ^preferable that ^R1 and ^R2 are each independently a hydrogen atom, an alkyl group which may have a substituent, or an aromatic group which may have a substituent, or that ^{R1 and R2} are bonded to form a ring.

When R ¹ and R ² are alkyl groups, the alkyl group may have an ether bond, an ester bond, an amide bond, a sulfide bond, a disulfide bond, or the like in the chain.
The number of carbon atoms in the alkyl group represented by ^R1 and ^R2 is preferably 1 to 40, more preferably 1 to 30, even more preferably 1 to 20, particularly preferably 1 to 10, and most preferably 1 to 5.

The substituents that the alkyl groups represented by ^R1 and ^R2 may have are not particularly limited as long as they do not impair the object of the present invention. Specific examples of the substituents that the alkyl groups may have include a hydroxyl group, an alkoxy group, an amino group, a cyano group, and a halogen atom. The alkylene group may be a straight-chain alkyl group or a branched-chain alkyl group, and a straight-chain alkyl group is preferred.

Specific examples of the alkyl group as ^R1 and ^R2 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethyl-n-hexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group.

The aromatic group which may have a substituent as R ¹ and R ² may be an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent.

The type of aromatic hydrocarbon group is not particularly limited as long as it does not impede the object of the present invention. The aromatic hydrocarbon group may be a monocyclic aromatic group, may be formed by condensing two or more aromatic hydrocarbon groups, or may be formed by bonding two or more aromatic hydrocarbon groups with a single bond. As the aromatic hydrocarbon group, a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, or a phenanthrenyl group is preferable.

The type of aromatic heterocyclic group is not particularly limited as long as it does not impair the object of the present invention. The aromatic heterocyclic group may be a monocyclic group or a polycyclic group. As the aromatic heterocyclic group, a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, an isoxazolyl group, an isothiazolyl group, a benzoxazolyl group, a benzothiazolyl group, and a benzoimidazolyl group are preferred.

Examples of the substituents that the phenyl group, polycyclic aromatic hydrocarbon group, or aromatic heterocyclic group may have include halogen atoms, hydroxyl groups, mercapto groups, sulfide groups, silyl groups, silanol groups, nitro groups, nitroso groups, sulfino groups, sulfo groups, sulfonato groups, phosphino groups, phosphinyl groups, phosphono groups, phosphonato groups, amino groups, ammonio groups, and organic groups. When the phenyl group, polycyclic aromatic hydrocarbon group, or aromatic heterocyclic group has multiple substituents, the multiple substituents may be the same or different.

When the substituent of the aromatic group is an organic group, examples of the organic group include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group. The organic group may contain a bond or a substituent other than the hydrocarbon group, such as a heteroatom, in the organic group. The organic group may be linear, branched, cyclic, or a combination of these structures. The organic group is usually monovalent, but may be a divalent or higher organic group when it forms a cyclic structure, etc.

When an aromatic group has substituents on adjacent carbon atoms, the two substituents bonded to the adjacent carbon atoms may be bonded to form a cyclic structure. Examples of cyclic structures include an aliphatic hydrocarbon ring and an aliphatic ring containing a heteroatom.

When the substituent of the aromatic group is an organic group, the bond contained in the organic group is not particularly limited as long as the effect of the present invention is not impaired, and the organic group may contain a bond containing a heteroatom such as an oxygen atom, a nitrogen atom, or a silicon atom. Specific examples of bonds containing a heteroatom include an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, a urethane bond, an imino bond (-N=C(-R)-, -C(=NR)-: R represents a hydrogen atom or an organic group), a carbonate bond, a sulfonyl bond, a sulfinyl bond, and an azo bond.

From the viewpoint of the heat resistance of the carboxylic acid compound represented by formula (1), the bond containing a heteroatom that the organic group may have is preferably an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, an amino bond (-NR-: R represents a hydrogen atom or a monovalent organic group), a urethane bond, an imino bond (-N=C(-R)-, -C(=NR)-: R represents a hydrogen atom or a monovalent organic group), a carbonate bond, a sulfonyl bond, or a sulfinyl bond.

When the organic group is a substituent other than a hydrocarbon group, the type of the substituent other than the hydrocarbon group is not particularly limited as long as it does not impair the purpose of the present invention. Specific examples of the substituent other than the hydrocarbon group include halogen atoms, hydroxyl groups, mercapto groups, sulfide groups, cyano groups, isocyano groups, cyanato groups, isocyanato groups, thiocyanato groups, isothiocyanato groups, silyl groups, silanol groups, alkoxy groups, alkoxycarbonyl groups, amino groups, monoalkylamino groups, dialkylaluminum groups, monoarylamino groups, diarylamino groups, carbamoyl groups, thiocarbamoyl groups, nitro groups, nitroso groups, carboxylate groups, acyl groups, acyloxy groups, sulfino groups, sulfonato groups, phosphino groups, phosphinyl groups, phosphonato groups, alkyl ether groups, alkenyl ether groups, alkyl thioether groups, alkenyl thioether groups, aryl ether groups, and aryl thioether groups. The hydrogen atoms contained in the above substituents may be substituted by hydrocarbon groups. Furthermore, the hydrocarbon group contained in the above substituent may be linear, branched, or cyclic.

As the substituents of the phenyl group, the polycyclic aromatic hydrocarbon group, or the aromatic heterocyclic group, preferred are an alkyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, an arylamino group having 1 to 12 carbon atoms, and a halogen atom.

^R1 and ^R2 may be bonded to each other to form a ring. The ring formed by bonding ^R1 and ^R2 is a nitrogen-containing heterocycle. The nitrogen-containing ring contains one or more elements selected from the group consisting of N, S, and O as ring-constituting elements.
The nitrogen-containing ring may be a monocycle or a polycycle, preferably a monocycle, and the nitrogen-containing heterocycle may be an aliphatic ring, an aromatic ring, or a condensed polycycle in which one or more aliphatic monocycles and one or more aromatic monocycles are condensed.

Suitable examples of the nitrogen-containing heterocycle formed by the combination of R ¹ and R ² include piperidine, piperazine, morpholine, pyrrolidine, pyrrole, imidazole, pyrazole, indole, benzimidazole, purine, phenoxazine, and phenothiazine. Among these, pyrrolidine, pyrrole, imidazole, and pyrazole are preferred, and imidazole is more preferred.
That is, in formula (1), it is preferable that R ¹ and R ² are bonded to form an imidazole ring. A carboxylic acid compound having an imidazole ring formed by bonding R ¹ and R ² has an excellent coating effect when coating metal oxide fine particles.

The nitrogen-containing heterocycle formed by the bonding of ^R1 and ^R2 may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonato group, and an organic group. The number of substituents on the nitrogen-containing heterocycle is not particularly limited.
When a plurality of substituents are present on the nitrogen-containing heterocycle, the plurality of substituents may be the same or different.

When the substituent on the nitrogen-containing heterocycle is an organic group, the organic group is the same as the organic group as the substituent when R ¹ and R ² are aromatic groups which may have a substituent.

When the substituent of the nitrogen-containing heterocycle is an organic group, the organic group is preferably an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. The alkyl group is preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. The aromatic hydrocarbon group is preferably a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, or a phenanthrenyl group, more preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group. The aromatic heterocyclic group is preferably a pyridyl group, a furyl group, a thienyl group, an imidazolyl group, a pyrazolyl group, an oxazolyl group, a thiazolyl group, an isoxazolyl group, an isothiazolyl group, a benzoxazolyl group, a benzothiazolyl group, or a benzimidazolyl group, and more preferably a furyl group or a thienyl group.

In formula (1), ^R3 is a monovalent organic group. The monovalent organic group represented by ^R3 is preferably an aromatic hydrocarbon group which may have a substituent, or an aliphatic group which may contain a heteroatom such as N, S, O, P, or a halogen atom.
When ^R3 is a monovalent organic group, the organic group preferably has 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, even more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms.
The aromatic group which may have a substituent as ^R3 is similar to the aromatic group which may have a substituent as ^R1 and ^R2 .

（式（１－１）中、Ｒ^３は置換基を有してもよい芳香族基であり、Ｒ^５は、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホナト基、又は有機基であり、ｎは０以上３以下の整数である。） R ⁴ is a single bond or a methylene group. When R ⁴ is a methylene group, the compound represented by formula (1) is preferably a carboxylic acid compound represented by the following formula (1-1) in that the desired effect of coating can be easily obtained.

(In formula (1-1), ^R3 is an aromatic group which may have a substituent, ^R5 is a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonato group, or an organic group, and n is an integer of 0 or more and 3 or less.)

When ^R4 is a single bond, the compound represented by formula (1) is preferably various amino acids having a structure included in formula (1). Such amino acids are easily available. In addition, when metal oxide fine particles are coated with such amino acids, the desired effect of coating can be easily obtained. The amino acid may be an L-form or a D-form, or a mixture of an L-form and a D-form.
Preferred examples of amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine, ornithine, citrulline, and theanine.
In addition, the amino group on the carbon atom adjacent to the carbonyl group of the amino acid may be substituted with an organic group such as an alkyl group having from 1 to 4 carbon atoms, a phenyl group, or an acetyl group. Such a carboxylic acid compound having a substituted amino group may be either an N-monosubstituted carboxylic acid compound or an N,N-disubstituted carboxylic acid compound.

In the above formula (1-1), R ³ is as described above for formula (1). As R ³ in formula (1-1), an aromatic group which may have a substituent is preferable.
In addition, when ^R5 in formula (1-1) is an organic group, the organic group is the same as the organic group as a substituent when ^R1 and ^R2 are aromatic groups which may have a substituent. When n is 2 or 3, the multiple ^R5s may be the same or different.

Among the carboxylic acid compounds represented by the above formula (1-1), the compound represented by the following formula (1-2) is preferred because it is inexpensive and can be easily synthesized.

（式（１－２）中、Ｒ^５及びｎは、式（１－１）と同じであり、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、及びＲ^１０は、それぞれ独立に、水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基である。ただし、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、及びＲ^１０のうち少なくとも１つは水素原子以外の基である。Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、及びＲ^１０のうち少なくとも２つが結合して環状構造を形成してもよい。Ｒ^１はＲ^８と結合して環状構造を形成してもよい。）

(In formula (1-2), R ⁵ and n are the same as in formula (1-1), and R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, or an organic group. However, at least one of R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ is a group other than a hydrogen atom. At least two of R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ may be bonded to form a cyclic structure. R ¹ may be bonded to R ⁸ to form a cyclic structure.)

In formula (1-2), when R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are organic groups, the organic groups are the same as the organic groups that R ¹ and R ² in formula (1) have as substituents. R ⁶ , R ⁷ , R ⁸ and R ⁹ are preferably hydrogen atoms in terms of the solubility of the carboxylic acid compound in a solvent.

Among them, at least one of R ⁶ , R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ is preferably the following substituent, and it is particularly preferable that R ¹⁰ is the following substituent. When R ¹⁰ is the following substituent, R ⁶ , R ⁷ , R ⁸ , and R ⁹ are preferably hydrogen atoms.
-O-R ¹¹
(R ¹¹ is a hydrogen atom or an organic group.)

When ^R11 is an organic group, the organic group is the same as the organic group that ^R1 and ^R2 in formula (1) have as a substituent. ^R11 is preferably an alkyl group, more preferably an alkyl group having 1 to 8 carbon atoms, particularly preferably an alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

Preferable specific examples of the carboxylic acid compound represented by formula (1) in which R ⁴ is a methylene group include the following compounds.

<Surface modification method>
The surface modification method is not particularly limited as long as it is a method that can contact metal oxide fine particles with the carboxylic acid compound represented by the above-mentioned formula (1) and/or a carboxylate derived from the carboxylic acid compound represented by formula (1).
Typically, surface modification is carried out by stirring and mixing metal oxide fine particles with the coating material, which is the carboxylic acid compound represented by the above-mentioned formula (1) and/or a carboxylate derived from the carboxylic acid compound represented by formula (1), in a dispersion medium.

The temperature during the surface modification is not particularly limited as long as the metal oxide fine particles and the coating material are not deteriorated or decomposed by heating.
Furthermore, the stirring and mixing time during the surface modification is not particularly limited.

The amount of the carboxylic acid compound represented by formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by formula (1) used for surface modification is preferably 0.01 parts by mass or more and 100 parts by mass or less, more preferably 0.1 parts by mass or more and 50 parts by mass or less, even more preferably 1 part by mass or more and 20 parts by mass or less, and even more preferably 6 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the metal oxide fine particles.

The dispersion medium that can be used during surface modification is not particularly limited as long as it can disperse metal oxide fine particles and is soluble in the carboxylic acid compound represented by formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by formula (1).
The dispersion medium may be water, an organic solvent, or an aqueous solution of an organic solvent, with an organic solvent being preferred.

Specific examples of organic solvents that can be used as dispersion media include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, and propylene glycol mono-n-butyl ether. (poly)alkylene glycol monoalkyl ethers such as pyrene glycol mono-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. (Poly)alkylene glycol monoalkyl ether acetates such as propylene glycol monoethyl ether acetate; other ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran; ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone; alkyl esters of lactate such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, Other esters such as ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-methylbutanemethyl, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl formate, isopentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, and ethyl 2-oxobutanoate; aromatic hydrocarbons such as toluene and xylene.

The amount of the dispersion medium used is not particularly limited, and is typically preferably 0.1 parts by mass or more and 5,000 parts by mass or less, more preferably 50 parts by mass or more and 1,000 parts by mass or less, and even more preferably 100 parts by mass or more and 500 parts by mass or less, relative to 100 parts by mass of the metal oxide microparticles.

The coating with the carboxylic acid compound and/or carboxylate is preferably carried out on modified metal oxide fine particles prepared in a solution or suspension containing a compound having an amide structure, or dispersed in the presence of a dispersion medium containing a compound having an amide structure.

When modified metal oxide microparticles are produced by this method, it is believed that the compound having an amide structure exerts some effect on the functional groups on the surface of the metal oxide microparticles. As a result, when the modified metal oxide microparticles produced by the above method are used as the target particles for surface modification in the above-mentioned method for producing surface-modified metal oxide microparticles, the surface of the modified metal oxide microparticles is well coated with the above-mentioned carboxylic acid compound and/or its carboxylate, and the dispersion stability of the surface-modified metal oxide microparticles in the dispersion liquid is particularly good.

The method of preparing metal oxide fine particles in a solution or suspension containing a compound having an amide structure and the method of dispersing metal oxide fine particles in the presence of a dispersion medium containing a compound having an amide structure are not particularly limited as long as they are methods for producing metal oxide fine particles under conditions in which the compound having an amide structure is not vaporized or thermally decomposed. Metal oxide fine particles may be prepared using a solution in which a carboxylic acid compound represented by formula (1) and/or a carboxylate derived from a carboxylic acid compound represented by formula (1) is dissolved in a solvent containing a compound having an amide structure.

The amount of the compound having an amide structure used is not particularly limited as long as the desired effect is obtained.
The amount of the compound having an amide structure used is not particularly limited, and typically, relative to 100 parts by mass of the metal oxide microparticles produced or the metal oxide microparticles to be dispersed, is preferably 10 parts by mass or more and 5,000 parts by mass or less, more preferably 20 parts by mass or more and 1,000 parts by mass or less, and even more preferably 50 parts by mass or more and 500 parts by mass or less.

（式（Ｓ０１）中、Ｒ^ｓ０１及びＲ^ｓ０２は、それぞれ独立に炭素原子数１以上３以下のアルキル基であり、Ｒ^ｓ０３は下式（Ｓ０１－１）又は下式（Ｓ０１－２）：

で表される基である。
式（Ｓ０１－１）中、Ｒ^ｓ０４は、水素原子又は水酸基であり、Ｒ^ｓ０５及びＲ^ｓ０６は、それぞれ独立に炭素原子数１以上３以下のアルキル基である。式（Ｓ０１－２）中、Ｒ^ｓ０７及びＲ^ｓ０８は、それぞれ独立に水素原子、又は炭素原子数１以上３以下のアルキル基である。） In a compound having an amide structure, the amide structure is a structure represented by -(C=O)-N<.
A preferred example of the compound having an amide structure is a compound represented by the following formula (S01).

In formula (S01), R ^s01 and R ^s02 each independently represent an alkyl group having 1 to 3 carbon atoms, and R ^s03 represents a group represented by the following formula (S01-1) or the following formula (S01-2):

It is a group represented by the following formula:
In formula (S01-1), R ^s04 is a hydrogen atom or a hydroxyl group, and R ^s05 and R ^s06 are each independently an alkyl group having 1 to 3 carbon atoms. In formula (S01-2), R ^s07 and R ^s08 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

Among the compounds represented by formula (S01), specific examples when R ^s03 is a group represented by formula (S01-1) include N,N,2-trimethylpropionamide, N-ethyl,N,2-dimethylpropionamide, N,N-diethyl-2-methylpropionamide, N,N,2-trimethyl-2-hydroxypropionamide, N-ethyl-N,2-dimethyl-2-hydroxypropionamide, and N,N-diethyl-2-hydroxy-2-methylpropionamide.

Among the compounds represented by formula (S01), specific examples when R ^a026 is a group represented by formula (S01-2) include N,N,N',N'-tetramethylurea, N,N,N',N'-tetraethylurea, and the like.

Among the compounds represented by formula (S01), N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea are particularly preferred.

As for the compound having an amide structure, preferred examples other than the compound represented by formula (S01) include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, and 1,3-dimethyl-2-imidazolidinone.
The compound having an amide structure may be used alone or in combination of two or more kinds.

The metal oxide fine particles to be surface-modified with the carboxylic acid compound represented by the above formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by the formula (1) may be coated metal oxide fine particles containing other coating agents. The coated metal oxide fine particles may be commercially available products (coated metal oxide fine particles or a dispersion containing the coated metal oxide fine particles) or may be obtained by a known method.

Other coating agents include:
Hydrocarbons having a carboxylic acid group, such as a linear carboxylic acid having from 4 to 20 carbon atoms (linear aliphatic carboxylic acid, preferably linear saturated aliphatic carboxylic acid, etc.), a branched carboxylic acid (branched aliphatic carboxylic acid), or a cyclic carboxylic acid (alicyclic carboxylic acid, preferably alicyclic carboxylic acid having no unsaturated double bond, etc.), are preferably used. For example, linear carboxylic acids such as butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, and stearic acid; branched carboxylic acids such as pivalic acid, 2,2-dimethylbutyric acid, 3,3-dimethylbutyric acid, 2,2-dimethylvaleric acid, 2,2-diethylbutyric acid, 3,3-diethylbutyric acid, 2-ethylhexanoic acid, 2-methylheptanoic acid, 4-methyloctanoic acid, and neodecanoic acid; cyclic carboxylic acids such as naphthenic acid and cyclohexanedicarboxylic acid; carboxylic acid compounds having an aromatic structure having at least one structure selected from the group consisting of a fluorene structure, an anthracene structure, a dibenzothiophene structure, a carbazole structure, a stilbene structure, a biphenyl structure, a bisphenol structure, and a naphthalene structure; and the above aromatic structures further having a (meth)acryloyl structure. carboxylic acid compounds having a structure such as those listed in the silane compounds (i) to (iii) described below; monovinyltrialkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and allyltrimethoxysilane; (meth)acryloxyalkylmonoalkyldialkoxysilanes such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane; (meth)acryloxyalkyltrialkoxysilanes such as 3-acryloxypropyltrimethoxysilane; non-alicyclic epoxyfluorene compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. non-alicyclic epoxy group-containing alkyl monoalkyl dialkoxy silanes such as 3-glycidoxypropyl methyl diethoxy silane; alicyclic epoxy group-containing alkyl tri (or di) alkoxy silanes such as 2-(3,4-epoxycyclohexyl) ethyl trimethoxy silane, 2-(3,4-epoxycyclohexyl) ethyl triethoxy silane, 2-(3,4-epoxycyclohexyl) methyl dimethoxy silane, and 2-(3,4-epoxycyclohexyl) methyl diethoxy silane; alicyclic epoxy group-containing alkyl tri (or di) alkoxy silanes such as 2-(3,4-epoxycyclohexyl) ethyl methyl diethoxy silane; alicyclic epoxy group-containing alkyl monoalkyl dialkoxy silanes such as 2-(3,4-epoxycyclohexyl) ethyl methyl diethoxy silane; [(3-ethyl-3-oxetanyl) methoxy] propyl trimethoxy silane, [(3-ethyl-3-oxetanyl) oxetanyl group-containing alkyltrialkoxysilanes such as oxetanyl)methoxy]propyltriethoxysilane; mercaptoalkyltrialkoxysilanes such as 3-mercaptopropyltrimethoxysilane; mercaptoalkylmonoalkyldialkoxysilanes such as 3-mercaptopropylmethyldimethoxysilane; other chain trialkoxysilanes such as n-octyltriethoxysilane, n-dodecyltrimethoxysilane, n-dodecyltriethoxysilane, n-hexadecyltrimethoxysilane, octadecyltrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxytri(ethyleneoxy)propyltrimethoxysilane, 1-hexenyltrimethoxysilane, and 1-octenyltrimethoxysilane; and ... hydrolytic condensation silicon compounds;
and the like, and one or more of them may be used in combination.

When the surface-modified metal oxide fine particles according to the present invention contain another coating agent, the mass ratio of the surface modification (coating) amount of the carboxylic acid compound represented by formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by formula (1) to the other coating agent in the surface-modified metal oxide fine particles may be, for example, 1/99 to 99/1, preferably 50/50 to 99/1, more preferably 70/30 to 97/3, and particularly preferably 80/20 to 95/5, in terms of improving dispersibility, as the carboxylic acid compound represented by formula (1) and/or the carboxylate derived from the carboxylic acid compound represented by formula (1)/the other coating agent.

The metal oxide particles surface-modified by the above method can be used for various purposes while dispersed in a dispersion medium, or after being separated from the dispersion medium by methods such as drying or centrifugation.

<Method for producing modified metal oxide fine particles>
The method for producing modified metal oxide microparticles includes preparing metal oxide microparticles in a solution or suspension containing a compound having an amide structure, or dispersing metal oxide microparticles in the presence of a dispersion medium containing a compound having an amide structure. The (raw) metal oxide microparticles to be modified may be coated metal oxide microparticles containing a carboxylic acid compound represented by formula (1) and/or a coating agent other than the carboxylate derived from the carboxylic acid compound represented by formula (1). The coated metal oxide microparticles may be commercially available products (coated metal oxide microparticles or a dispersion containing the coated metal oxide microparticles) or may be obtained using a known method.

As described above, when the modified metal oxide microparticles produced by the above-mentioned method are used as the target particles for surface modification in the above-mentioned method for producing surface-modified metal oxide microparticles, it is believed that the dispersion stability of the surface-modified metal oxide microparticles in the dispersion liquid is particularly good.
Therefore, the above-mentioned method for producing modified metal oxide fine particles is preferable as a method for producing metal oxide fine particles that are the subject of surface modification in the above-mentioned method for producing surface-modified metal oxide fine particles.
Furthermore, the modified metal oxide fine particles produced by the above method tend to have improved dispersion stability in organic solvents and the like even in a state where they are not surface-modified.

The method for preparing metal oxide fine particles in a solution or suspension containing a compound having an amide structure and the method for dispersing metal oxide fine particles in the presence of a dispersion medium containing a compound having an amide structure are as described above.

≪Metal oxide fine particle dispersion liquid≫
The metal oxide fine particle dispersion liquid contains a metal oxide (A). The metal oxide (A) is in the form of fine particles. The metal oxide fine particle dispersion liquid contains the above-mentioned surface-modified metal oxide (A) as the metal oxide (A). Contains metal oxide fine particles.
The content of the surface-modified metal oxide fine particles in the metal oxide (A) is not particularly limited as long as it does not impair the object of the present invention. ) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.

The metal oxide microparticle dispersion may be a dispersion in which the metal oxide (A) is dispersed in a molten resin or the like, a dispersion in which the metal oxide (A) is dispersed in a solvent, or a dispersion in which the metal oxide (A) is dispersed in a liquid in which various added components are dissolved in a solvent.
Since the metal oxide fine particle dispersion contains the above-mentioned surface-modified metal oxide fine particles as the metal oxide (A), the metal oxide fine particle dispersion has excellent dispersion stability, and therefore the metal oxide fine particle dispersion is suitably used in various applications.

The use of the metal oxide fine particle dispersion liquid is not particularly limited, and examples of the use of the metal oxide fine particle dispersion liquid include a polishing liquid, a sealing composition, and a composition for forming a high refractive index film.
When the metal oxide fine particle dispersion liquid is used for sealing purposes, film forming purposes, or the like, the metal oxide fine particle dispersion liquid preferably contains the base component (B).

When the metal oxide microparticle dispersion liquid contains the base material component (B) and when it contains the metal oxide (A), the amount of the metal oxide (A) in the metal oxide microparticle dispersion liquid is appropriately determined taking into consideration the use of the metal oxide microparticle dispersion liquid.
When the metal oxide microparticle dispersion liquid contains the base component (B), the amount of the metal oxide (A) is preferably 0.1 parts by mass or more and 200 parts by mass or less, more preferably 1 part by mass or more and 150 parts by mass or less, and particularly preferably 3 parts by mass or more and 100 parts by mass or less, per 100 parts by mass of the base component (B) in the metal oxide microparticle dispersion liquid.
The upper limit of the amount of metal oxide (A) may be 80 parts by mass or less, 50 parts by mass or less, or 30 parts by mass or less, per 100 parts by mass of base component (B).
The lower limit of the amount of the metal oxide (A) may be 5 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more, per 100 parts by mass of the base component (B).

<Base material component (B)>
The base material component (B) is a component that imparts to the metal oxide microparticle dispersion the formability that enables it to be directly used to produce articles of the desired shape by well-known methods such as melt processing, or the like, or the formability that enables it to be used to produce articles of the desired shape by treatment such as exposure to light, heating, or reaction with water.
The base component (B) is not particularly limited as long as it is a material that can impart the desired shapeability to the metal oxide fine particle dispersion.
As the base material component (B), typically used are resin materials made of polymeric compounds, thermosetting materials which are cured by crosslinking upon heating to generate polymeric compounds or by chemical modification such as intramolecular cyclization upon heating, photopolymerizable compounds which can be cured upon exposure to light, and hydrolytically condensable silane compounds which are hydrolytically condensed by moisture in the composition or in the atmosphere.
Examples of the hydrolytically condensable silane compound include alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane. The hydrolytically condensable silane compound may be a partial hydrolytic condensate of these silane compounds.

（式（ｂ－０１）中、Ｗ^０１及びＷ^０２は、それぞれ独立に、下記式（ｂ－０２）：

で表される基であり、
式（ｂ－０２）中、環Ｚ^０１は芳香族炭化水素環を示し、Ｘ^０１は単結合又は－Ｓ－で示される基を示し、Ｒ^０１は単結合、炭素原子数１以上４以下のアルキレン基、又は炭素原子数が１以上４以下であるアルキレンオキシ基を示し、Ｒ^０１がアルキレンオキシ基である場合、アルキレンオキシ基中の酸素原子が環Ｚ^０１と結合し、Ｒ^０１は１価炭化水素基、水酸基、－ＯＲ^４Ａで示される基、－ＳＲ^４Ｂで示される基、アシル基、アルコキシカルボニル基、ハロゲン原子、ニトロ基、シアノ基、メルカプト基、カルボキシ基、アミノ基、カルバモイル基、－ＮＨＲ^４Ｃで示される基、－Ｎ（Ｒ^４Ｄ）_２で示される基、スルホ基、又は１価炭化水素基、－ＯＲ^４Ａで示される基、－ＳＲ^４Ｂで示される基、アシル基、アルコキシカルボニル基、－ＮＨＲ^４Ｃで示される基、若しくは－Ｎ（Ｒ^４Ｄ）_２で示される基に含まれる炭素原子に結合した水素原子の少なくとも一部が１価炭化水素基、水酸基、－ＯＲ^４ａで示される基、－ＳＲ^４Ｂで示される基、アシル基、アルコキシカルボニル基、ハロゲン原子、ニトロ基、シアノ基、メルカプト基、カルボキシル基、アミノ基、カルバモイル基、－ＮＨＲ^４Ｃで示される基、－Ｎ（Ｒ^４Ｄ）_２で示される基、メシルオキシ基、若しくはスルホ基で置換された基を示し、Ｒ^４Ａ～Ｒ^４Ｄは独立に１価炭化水素基を示し、Ｍは０以上の整数を示し、Ｒ^０３は、水素原子、ビニル基、チイラン－２－イルメチル基、グリシジル基、又は（メタ）アクリロイル基であり、
Ｗ^０１とＷ^０２との双方がＲ^０３として水素原子を有することはなく、
環Ｙ^０１及び環Ｙ^０２は同一の又は異なる芳香族炭化水素環を示し、Ｒ^００は単結合、置換基を有してもよいメチレン基、置換基を有してもよく、２個の炭素原子間にヘテロ原子を含んでもよいエチレン基、－Ｏ－で示される基、－ＮＨ－で示される基、又は－Ｓ－で示される基を示し、Ｒ^３Ａ及びＲ^３Ｂは独立にシアノ基、ハロゲン原子、又は１価炭化水素基を示し、Ｎ１及びＮ２は独立に０～４の整数を示す。）
で表される化合物を含むのも好ましい。
上記式（ｂ－０１）で表される化合物は、必要に応じて硬化剤と組み合わせて使用されることによって、熱硬化又は光硬化し得る。 In addition, the metal oxide fine particle dispersion liquid is preferably a base component (B) represented by the following formula (b-01):

In formula (b-01), W ⁰¹ and W ⁰² each independently represent the following formula (b-02):

is a group represented by
In formula (b-02), ring Z ⁰¹ represents an aromatic hydrocarbon ring; X ⁰¹ represents a single bond or a group represented by -S-; R ⁰¹ represents a single bond, an alkylene group having from 1 to 4 carbon atoms, or an alkyleneoxy group having from 1 to 4 carbon atoms; when R ⁰¹ is an alkyleneoxy group, an oxygen atom in the alkyleneoxy group is bonded to ring Z ⁰¹ ; R ⁰¹ represents a monovalent hydrocarbon group, a hydroxyl group, a group represented by -OR ^4A , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a mercapto group, a carboxy group, an amino group, a carbamoyl group, a group represented by -NHR ^4C , a group represented by -N(R ^4D ) ₂ , a sulfo group, or a monovalent hydrocarbon group, a group represented by -OR ^4A , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, -NHR at least a portion of the hydrogen atoms bonded to carbon atoms contained in the group represented by ^-N (R ^{4D ) 2 or the group represented by -N(R 4D} _{) 2} are substituted with a monovalent hydrocarbon group, a hydroxyl group, a group represented by -OR ^4a , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a mercapto group, a carboxyl group, an amino group, a carbamoyl group, a group represented by -NHR ^4C , a group represented by -N(R ^4D ) ₂ , a mesyloxy group, or a sulfo group; R ^4A to R ^4D each independently represent a monovalent hydrocarbon group; M represents an integer of 0 or greater; and R ⁰³ represents a hydrogen atom, a vinyl group, a thiirane-2-ylmethyl group, a glycidyl group, or a (meth)acryloyl group;
Both W ⁰¹ and W ⁰² do not have a hydrogen atom as R ⁰³ ;
Ring Y ⁰¹ and ring Y ⁰² are the same or different aromatic hydrocarbon rings; R ⁰⁰ is a single bond, a methylene group which may have a substituent, an ethylene group which may have a substituent and which may contain a heteroatom between the two carbon atoms, a group represented by -O-, a group represented by -NH-, or a group represented by -S-; R ^3A and R ^3B are independently a cyano group, a halogen atom, or a monovalent hydrocarbon group; and N1 and N2 are independently an integer of 0 to 4.
It is also preferable that the compound is represented by the following formula:
The compound represented by the above formula (b-01) can be thermally or photocured by being used in combination with a curing agent as necessary.

In the above formula (b-02), examples of ring Z ⁰¹ include a benzene ring, a fused polycyclic aromatic hydrocarbon ring [for example, a fused bicyclic hydrocarbon ring (e.g., a C _8-20 fused bicyclic hydrocarbon ring such as a naphthalene ring, preferably a C _10-16 fused bicyclic hydrocarbon ring), a fused tricyclic aromatic hydrocarbon ring (e.g., an anthracene ring, a phenanthrene ring, etc.) and other fused dicyclic to tetracyclic aromatic hydrocarbon rings]. Ring Z ⁰¹ is preferably a benzene ring or a naphthalene ring, more preferably a naphthalene ring. Note that W ⁰¹ and W ⁰² in formula (b-01) are each independently a group represented by the above formula (b-02), and therefore W ⁰¹ and W ⁰² each include ring Z ⁰¹ . Ring Z ⁰¹ contained in W ⁰¹ and ring Z ⁰¹ contained in W ⁰² may be the same or different. For example, one ring may be a benzene ring and the other ring may be a naphthalene ring, etc., and it is particularly preferable that both rings are naphthalene rings.

In addition, the substitution position of ring Z ⁰¹ bonded via X ⁰¹ to the carbon atom to which both W ⁰¹ and W ⁰² are directly bonded is not particularly limited. For example, when ring Z ⁰¹ is a naphthalene ring, the group corresponding to ring Z ⁰¹ bonded to the carbon atom may be a 1-naphthyl group, a 2-naphthyl group, etc.

In the above formula (b-02), X ⁰¹ independently represents a single bond or a group represented by —S—, and is typically a single bond.

In the above formula (b-02), examples of R ⁰¹ include a single bond; an alkylene group having 1 to 4 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, a propylene group, or a butane-1,2-diyl group; and an alkyleneoxy group having 1 to 4 carbon atoms, such as a methyleneoxy group, an ethyleneoxy group, or a propyleneoxy group. Of these, a single bond; a C _2-4 alkylene group (particularly a C _2-3 alkylene group, such as an ethyleneoxy group or a propylene group); or a C _2-4 alkyleneoxy group (particularly a C _2-3 alkylene group, such as an ethyleneoxy group or a propyleneoxy group) is preferable, and a single bond is more preferable. Note that when R ⁰¹ is an alkyleneoxy group, the oxygen atom in the alkyleneoxy group bonds to the ring Z ⁰¹ . In addition, W ⁰¹ and W ⁰² in formula (b-01) are each independently a group represented by the following formula (b-02), and therefore W ⁰¹ and W ⁰² each contain a divalent group R ^01. The R ⁰¹ contained in W ⁰¹ and the R ⁰¹ contained in W ⁰² may be the same or different.

In the above formula (b-02), examples of R ⁰² include monovalent hydrocarbon groups such as alkyl groups (for example, C _1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, preferably C _1-8 alkyl groups, and more preferably C _1-6 alkyl groups), cycloalkyl groups (C _5-10 cycloalkyl groups such as cyclohexyl, preferably C _5-8 cycloalkyl groups, and more preferably C _5-6 cycloalkyl groups), aryl groups (for example, C _6-14 aryl groups such as phenyl, tolyl, xylyl, and naphthyl, preferably C _6-10 aryl groups, and more preferably C _6-8 aryl groups), and aralkyl groups (C _6-10 aryl-C _1-4 alkyl groups such as benzyl and phenethyl); hydroxyl groups; and alkoxy groups (C _1-12 alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, preferably C _1-8 alkoxy groups, and more preferably C a group represented by _{-OR 4A} , such as a cycloalkoxy group (a C _5-10 cycloalkoxy group such as a cyclohexyloxy group), an aryloxy group (a C _6-10 aryloxy group such as a phenoxy group), or an aralkyloxy group (for example, a C _6-10 aryl-C _1-4 alkyloxy group such as a benzyloxy group) [wherein ^{R 4A represents} a monovalent hydrocarbon group (such as the monovalent hydrocarbon groups exemplified above). ]; groups represented by -SR 4B such as alkylthio groups (C _1-12 alkylthio groups such as methylthio, ethylthio, propylthio, and butylthio, preferably C _1-8 alkylthio groups, and more preferably C _1-6 alkylthio groups), cycloalkylthio groups (C _5-10 cycloalkylthio groups such as cyclohexylthio), arylthio groups (C _6-10 arylthio groups such as phenylthio), and aralkylthio groups (for example, C _6-10 aryl-C _1-4 alkylthio groups such as benzylthio ^{) [wherein R 4B represents} a monovalent hydrocarbon group (such as the monovalent hydrocarbon groups exemplified above). ]; an acyl group (a C _1-6 acyl group such as an acetyl group, etc.); an alkoxycarbonyl group (a C _1-4 alkoxy-carbonyl group such as a methoxycarbonyl group, etc.); a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.); a nitro group; a cyano group; a mercapto group; a carboxyl group; an amino group; a carbamoyl group; an alkylamino group (a C _1-12 alkylamino group such as a methylamino group, an ethylamino group, a propylamino group, a butylamino group, etc., preferably a C _1-8 alkylamino group, more preferably a C _1-6 alkylamino group, etc.), a cycloalkylamino group (a C _5-10 cycloalkylamino group such as a cyclohexylamino group, etc.), an arylamino group (a C _6-10 arylamino group such as a phenylamino group), an aralkylamino group (for example, a C _6-10 aryl-C _1-4 alkylamino group such as a benzylamino group, etc.), or the like represented by -NHR ^4C [wherein, R ^4C represents a monovalent hydrocarbon group (such as the monovalent hydrocarbon groups exemplified above). ]; a group represented by -N(R 4D ) 2, such as a dialkylamino group (a di(C _1-12 alkyl)amino group such as a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, etc., preferably a di(C _1-8 alkyl)amino group, more preferably a di(C _1-6 alkyl)amino group), a dicycloalkylamino group (a di(C _5-10 cycloalkyl)amino group such as a dicyclohexylamino group), a diarylamino group (a di(C _6-10 aryl)amino group _such as a diphenylamino ^group ), or a diaralkylamino group (for example, ^a di(C _6-10 aryl-C _1-4 alkyl)amino group such as a dibenzylamino group). a (meth)acryloyloxy group; a sulfo group; a group in which at least a part of the hydrogen atoms bonded to carbon atoms contained in the above-mentioned monovalent hydrocarbon group, the group represented by -OR ^4A , the group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, the group represented by -NHR ^4C , or the group represented by -N(R ^4D ) ₂ is substituted with the above-mentioned monovalent hydrocarbon group, a hydroxyl group, the group represented by -OR ^4A , the group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a mercapto group, a carboxyl group, an amino group, a carbamoyl group, the group represented by -NHR ^4C , the group represented by -N(R ^4D ) ₂ , a (meth)acryloyloxy group, a mesyloxy group, or a sulfo group [for example, an alkoxyaryl group (for example, a C _1-4 alkoxy C such as a methoxyphenyl group, _aryl groups (for example, C _1-4 alkoxy-carbonyl C _6-10 aryl groups such as methoxycarbonylphenyl group, ethoxycarbonylphenyl group, etc.)].

Among these, typically, R ⁰² may be a monovalent hydrocarbon group, a group represented by -OR ^4A , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a group represented by -NHR ^4C , a group represented by -N(R ^4D ) ₂ , or the like.

Preferred examples of R ⁰² include monovalent hydrocarbon groups [for example, an alkyl group (e.g., a C _1-6 alkyl group), a cycloalkyl group (e.g., a C _5-8 cycloalkyl group), an aryl group (e.g., a C _6-10 aryl group), an aralkyl group (e.g., a C _6-8 aryl-C _1-2 alkyl group), etc.], alkoxy groups (e.g., a C _1-4 alkoxy group), etc. In particular, R ⁰² is preferably a monovalent hydrocarbon group (particularly an alkyl group) such as an alkyl group [a C _1-4 alkyl group (particularly a methyl group), etc.], an aryl group [for example, a C _6-10 aryl group (particularly a phenyl group), etc.], etc.

When M is an integer of 2 or more, the multiple R ⁰² may be different from each other or may be the same. Furthermore, R ⁰² contained in W ⁰¹ and R ⁰² contained in W ² may be the same or may be different.

In the above formula (b-02), the number M of R ⁰² can be selected depending on the type of ring Z ⁰¹ , and may be, for example, 0 to 4, preferably 0 to 3, more preferably 0 to 2. M in W ⁰¹ and M in W ⁰² may be the same or different.

In the above formula (b-02), R ⁰³ is a hydrogen atom, a vinyl group, a thiirane-2-ylmethyl group, a glycidyl group, or a (meth)acryloyl group. Note that both W ⁰¹ and W ⁰² cannot have a hydrogen atom as R ⁰³ .
A vinyloxy group, a thiiran-2-ylmethyl group, and a glycidyl group are all cationically polymerizable functional groups. Therefore, a compound represented by formula (b-01) having a vinyl group, a thiiran-2-ylmethyl group, or a glycidyl group as R ⁰³ is a cationically polymerizable compound.
On the other hand, a compound represented by formula (b-01) having a (meth)acryloyl group as R ⁰³ is a radically polymerizable compound.

R ⁰³ contained in W ⁰¹ and R ⁰³ contained in W ⁰² may be the same or different, so long as they are not both hydrogen atoms. It is preferable that both R ⁰³ contained in W ⁰¹ and R ⁰³ contained in W ⁰² are a vinyl group, a thiirane-2-ylmethyl group, or a glycidyl group, and it is more preferable that both are the same group selected from the group consisting of a vinyl group, a thiirane-2-ylmethyl group, and a glycidyl group.
It is also preferable that both of R ⁰³ contained in W ⁰¹ and R ⁰³ contained in W ⁰² are a (meth)acryloyl group.

As R ⁰³ , a vinyl group, a glycidyl group, or a (meth)acryloyl group is preferable because the compound represented by formula (b-01) can be easily synthesized and obtained.
In addition, since a curable metal oxide microparticle dispersion can be prepared while reducing the number of types of components, it is preferable that the compound represented by formula (b-01) has only groups selected from a vinyl group, a thiirane-2-ylmethyl group, and a glycidyl group as reactive groups, or has only a (meth)acryloyl group as reactive groups.

In the above formula (b-01), examples of ring Y ⁰¹ and ring Y ⁰² include a benzene ring, a fused polycyclic aromatic hydrocarbon ring [for example, a fused bicyclic hydrocarbon ring (e.g., a C _8-20 fused bicyclic hydrocarbon ring such as a naphthalene ring, preferably a C _10-16 fused bicyclic hydrocarbon ring), a fused tricyclic aromatic hydrocarbon ring (e.g., an anthracene ring, a phenanthrene ring, etc.) and other fused dicyclic to tetracyclic aromatic hydrocarbon rings]. Ring Y ⁰¹ and ring Y ⁰² are preferably a benzene ring or a naphthalene ring, more preferably a benzene ring. Ring Y ⁰¹ and ring Y ⁰² may be the same or different, and for example, one ring may be a benzene ring and the other ring may be a naphthalene ring, etc.

In the above formula (b-01), R ⁰⁰ represents a single bond, a methylene group which may have a substituent, an ethylene group which may have a substituent and which may contain a heteroatom between two carbon atoms, a group represented by -O-, a group represented by -NH-, or a group represented by -S-, and is typically a single bond. Examples of the substituent include a cyano group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), a monovalent hydrocarbon group [for example, an alkyl group (a C _1-6 alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, etc.), an aryl group (a C _6-10 aryl group such as a phenyl group, etc.)], and examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, etc.

In the above formula (b-01), R ^3A and R ^3B are usually non-reactive substituents such as a cyano group, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), a monovalent hydrocarbon group [for example, an alkyl group, an aryl group (a C _6-10 aryl group such as a phenyl group), etc.], and are preferably a cyano group or an alkyl group, and are particularly preferably an alkyl group. Examples of the alkyl group include a C _1-6 alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a tert-butyl group, etc. (for example, a C _1-4 alkyl group, particularly a methyl group). When N1 is an integer of 2 or more, R ^3A may be different from each other or may be the same. When N2 is an integer of 2 or more, R ^3B may be different from each other or may be the same. Furthermore, R ^3A and R ^3B may be the same or may be different. Furthermore, the bonding positions (substitution positions) of R ^3A and R ^3B to the ring Y ⁰¹ and the ring Y ⁰² are not particularly limited. The substitution numbers N1 and N2 are preferably 0 or 1, particularly preferably 0. N1 and N2 may be the same or different.

The compound represented by the formula (b-01) has a cationic polymerizable functional group while maintaining excellent optical and thermal properties, and therefore has high reactivity. In particular, when the ring Y ⁰¹ and the ring Y ⁰² are benzene rings and R ⁰⁰ is a single bond, the compound represented by the formula (b-01) has a fluorene skeleton and is further excellent in optical and thermal properties.
Furthermore, the compound represented by the above formula (b-01) gives a cured product having high hardness, and is therefore preferable as the base component (B) in the metal oxide fine particle dispersion.

Of the compounds represented by the above formula (b-01), particularly preferred examples include epoxy group-containing fluorene compounds such as 9,9-bis[4-[2-(glycidyloxy)ethoxy]phenyl]-9H-fluorene, 9,9-bis[4-[2-(glycidyloxy)ethyl]phenyl]-9H-fluorene, 9,9-bis[4-(glycidyloxy)-3-methylphenyl]-9H-fluorene, 9,9-bis[4-(glycidyloxy)-3,5-dimethylphenyl]-9H-fluorene, 9,9-bis(6-glycidyloxynaphthalene-1-yl)-9H-fluorene and 9,9-bis(5-glycidyloxynaphthalene-2-yl)-9H-fluorene; and compounds represented by the following formula:

Among the compounds represented by formula (b-01) explained above, the following compounds are particularly preferable.

[Resin material]
Examples of the resin material of the base material component (B) include polyacetal resin, polyamide resin, polycarbonate resin, polyester resin (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyarylate, etc.), FR-AS resin, FR-ABS resin, AS resin, ABS resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, fluorine-based resin, polyimide resin, polyamideimide resin, polyamide bismaleimide resin, polyetherimide resin, polybenzoxazole resin, polybenzothiazole resin, polybenzimidazole resin, silicone resin, BT resin, polymethylpentene, ultra-high molecular weight polyethylene, FR-polypropylene, (meth)acrylic resin (e.g., polymethyl methacrylate, etc.), and polystyrene.

When a resin material is used as the base material component (B), a metal oxide fine particle dispersion in which a predetermined amount of the metal oxide (A) containing the above-mentioned surface-modified metal oxide fine particles is mixed with the resin material is formed into a film or the like by a conventionally known method, thereby producing various articles in the form of a film, etc. The form of the article produced using the metal oxide fine particle dispersion is preferably a film.
The metal oxide fine particle dispersion may be in the form of a melt or a solution.

Examples of the film formation method include melt processing methods such as the T-die method (casting method), the inflation method, and the press method, as well as casting methods using a solution, the inkjet method, and the spin coating method.
In the casting method, the inkjet method, and the spin coating method, a liquid containing a resin material and a metal oxide (A) is applied or poured onto a substrate to form a film, and then, if necessary, the solvent is removed from the film by a method such as heating, thereby forming a metal oxide-containing film.
The metal oxide-containing film obtained by using the metal oxide fine particle dispersion liquid may be subjected to a stretching treatment such as uniaxial stretching or biaxial stretching, if necessary.

When the above-mentioned resin material is used as the base material component (B), the metal oxide microparticle dispersion may contain additives such as antioxidants, ultraviolet absorbers, flame retardants, release agents, plasticizers, fillers other than the metal oxide (A), and reinforcing materials, as necessary.
When the metal oxide fine particle dispersion is a composition for casting, the metal oxide fine particle dispersion may contain a solvent, the type of which is appropriately selected depending on the type of resin material.

[Thermosetting materials]
Examples of the thermosetting material include precursor materials of various thermosetting resins that have been widely used in the past. Specific examples of the thermosetting resin include phenolic resin, epoxy resin, oxetane resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane resin, polyimide resin, polybenzoxazole resin, polybenzimidazole resin, etc.

Resins that undergo an aromatic ring-forming reaction within a molecule and/or a crosslinking reaction between molecules when heated are also suitable for use as thermosetting materials. Hereinafter, resins that undergo an aromatic ring-forming reaction within a molecule and/or a crosslinking reaction between molecules when heated are also referred to as precursor resins.

Among these, epoxy resin precursors and precursor resins are particularly preferred because they are particularly easy to form metal oxide-containing films that are excellent in heat resistance, chemical resistance, mechanical properties, and the like.
Hereinafter, with regard to the thermosetting material, a precursor material that is particularly suitable as the base component (B) will be described.

(Epoxy resin precursor)
As the epoxy resin precursor, various epoxy compounds widely known in the art can be used. In the metal oxide fine particle dispersion, if necessary, a curing agent or a curing accelerator can be used in combination with an epoxy resin precursor to make the metal oxide fine particle dispersion into a thermosetting composition. In addition, in the metal oxide fine particle dispersion, a photosensitive curing agent can be used in combination with an epoxy resin precursor to make the metal oxide fine particle dispersion into a photosensitive composition that can be photocured.
The molecular weight of the epoxy compound as the epoxy resin precursor is not particularly limited. Among the epoxy compounds, a polyfunctional epoxy compound having two or more epoxy groups in the molecule is preferred because it is easy to form a metal oxide-containing film having excellent heat resistance, chemical resistance, mechanical properties, etc. The epoxy resin precursor can be used alone or in combination of two or more kinds.

The polyfunctional epoxy compound is not particularly limited as long as it is a bifunctional or higher epoxy compound. Examples of polyfunctional epoxy compounds include bifunctional epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD type epoxy resins, naphthalene type epoxy resins, tetrabromobisphenol A type epoxy resins, and biphenyl type epoxy resins; glycidyl ester type epoxy resins such as dimer acid glycidyl ester and triglycidyl ester; glycidyl amine type epoxy resins such as tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, tetraglycidylmeta-xylylenediamine, and tetraglycidylbisaminomethylcyclohexane; hydantoin type epoxy resins such as 1,3-diglycidyl-5-methyl-5-ethylhydantoin; hydroquinone type epoxy resins; fluorene type epoxy resins; heterocyclic esters such as triglycidyl isocyanurate. trifunctional epoxy resins such as phloroglucinol triglycidyl ether, trihydroxybiphenyl triglycidyl ether, trihydroxyphenylmethane triglycidyl ether, glycerin triglycidyl ether, 2-[4-(2,3-epoxypropoxy)phenyl]-2-[4-[1,1-bis[4-(2,3-epoxypropoxy)phenyl]ethyl]phenyl]propane, and 1,3-bis[4-[1-[4-(2,3-epoxypropoxy)phenyl]-1-[4-[1-[4-(2,3-epoxypropoxy)phenyl]-1-methylethyl]phenyl]ethyl]phenoxy]-2-propanol; and tetrafunctional epoxy resins such as tetrahydroxyphenylethane tetraglycidyl ether, tetraglycidylbenzophenone, bisresorcinol tetraglycidyl ether, and tetraglycidoxybiphenyl. These epoxy compounds may be halogenated or hydrogenated.

Commercially available polyfunctional epoxy compounds include, for example, JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, and YX4000 manufactured by Japan Epoxy Resins Co., Ltd., Epicron 830, EXA835LV, HP4032D, and HP820 manufactured by DIC Corporation, EP4100 series, EP4000 series, and EPU series manufactured by ADEKA Corporation, and Celoxide series (2021, 20 21P, 2083, 2085, 3000, etc.), Epolead series, EHPE series, YD series, YDF series, YDCN series, YDB series manufactured by Nippon Steel Chemical Co., Ltd., phenoxy resin (polyhydroxy polyether synthesized from bisphenols and epichlorohydrin, having epoxy groups at both ends; YP series, etc.), Denacol series manufactured by Nagase ChemteX Corporation, Epolite series manufactured by Kyoeisha Chemical Co., Ltd., etc., but are not limited to these.

In addition, alicyclic epoxy compounds are also preferred as polyfunctional epoxy compounds because they give cured products with high hardness. Specific examples of alicyclic epoxy compounds include 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, trimethylcaprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, and α-caprolactone-modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate. Examples of epoxy resins include epoxycyclohexane carboxylate, β-methyl-δ-valerolactone modified 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), di(3,4-epoxycyclohexylmethyl)ether of ethylene glycol, ethylene bis(3,4-epoxycyclohexane carboxylate), dioctyl epoxycyclohexahydrophthalate, and di-2-ethylhexyl epoxycyclohexahydrophthalate, epoxy resins having tricyclodecene oxide groups, and compounds represented by the following formulas (a01-1) to (a01-5).

（式（ａ０１－１）中、Ｚ^０１は単結合又は連結基（１以上の原子を有する２価の基）を示す。Ｒ^ａ０１～Ｒ^ａ０１８は、それぞれ独立に、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。） Among these specific examples of the alicyclic epoxy compounds, the alicyclic epoxy compounds represented by the following formulas (a01-1) to (a01-5) are preferred because they give cured products with high hardness.

(In formula (a01-1), Z ⁰¹ represents a single bond or a linking group (a divalent group having one or more atoms). R ^a01 to R ^a018 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group.)

Examples of the linking group Z ⁰¹ include divalent groups selected from the group consisting of divalent hydrocarbon groups, -O-, -O-CO-, -S-, -SO-, -SO ₂ -, -CBr ₂ -, -C(CBr ₃ ) ₂ -, -C(CF ₃ ) ₂ -, and -R ^a019 -O-CO-, and groups in which a plurality of these are bonded together.

Examples of the divalent hydrocarbon group that is the linking group Z include linear or branched alkylene groups having 1 to 18 carbon atoms, and divalent alicyclic hydrocarbon groups. Examples of the linear or branched alkylene groups having 1 to 18 carbon atoms include methylene, methylmethylene, dimethylmethylene, dimethylene, and trimethylene. Examples of the divalent alicyclic hydrocarbon groups include cycloalkylene groups (including cycloalkylidene groups) such as 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylidene.

R ^a019 is an alkylene group having 1 to 8 carbon atoms, and is preferably a methylene group or an ethylene group.

（式（ａ０１－２）中、Ｒ^ａ０１～Ｒ^ａ０１８は、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。Ｒ^ａ０２及びＲ^ａ０１０は、互いに結合してもよい。Ｒ^ａ０１３及びＲ^ａ０１６は互いに結合して環を形成してもよい。ｍ^ａ１は、０又は１である。）

(In formula (a01-2), R ^a01 to R ^a018 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R ^a02 and R ^a010 may be bonded to each other. R ^a013 and R ^a016 may be bonded to each other to form a ring. m ^a1 is 0 or 1.)

（式（ａ０１－２－１）中、Ｒ^ａ０１～Ｒ^ａ０１２は、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。Ｒ^ａ０２及びＲ^ａ０１０は互いに結合して環を形成してもよい。） As the alicyclic epoxy compound represented by the above formula (a01-2), a compound represented by the following formula (a01-2-1), which corresponds to the compound in which m ^a1 in the above formula (a01-2) is 0, is preferable.

(In formula (a01-2-1), R ^a01 to R ^a012 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R ^a02 and R ^a010 may be bonded to each other to form a ring.)

（式（ａ０１－３）中、Ｒ^ａ０１～Ｒ^ａ０１０は、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。Ｒ^ａ０２及びＲ^ａ０８は、互いに結合してもよい。）

(In formula (a01-3), R ^a01 to R ^a010 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R ^a02 and R ^a08 may be bonded to each other.)

（式（ａ０１－４）中、Ｒ^ａ０１～Ｒ^ａ０１２は、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。Ｒ^ａ０２及びＲ^ａ０１０は、互いに結合してもよい。）

(In formula (a01-4), R ^a01 to R ^a012 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group. R ^a02 and R ^a010 may be bonded to each other.)

（式（ａ０１－５）中、Ｒ^ａ０１～Ｒ^ａ０１２は、水素原子、ハロゲン原子、及び有機基からなる群より選択される基である。）

(In formula (a01-5), R ^a01 to R ^a012 are groups selected from the group consisting of a hydrogen atom, a halogen atom, and an organic group.)

In formulae (a01-1) to (a01-5), when R ^a01 to R ^a018 are organic groups, the organic group is not particularly limited as long as it does not impair the object of the present invention, and may be a hydrocarbon group, a group consisting of carbon atoms and halogen atoms, or a group containing heteroatoms such as halogen atoms, oxygen atoms, sulfur atoms, nitrogen atoms, and silicon atoms in addition to carbon atoms and hydrogen atoms. Examples of halogen atoms include chlorine atoms, bromine atoms, iodine atoms, and fluorine atoms.

As the organic group, a hydrocarbon group, a group consisting of carbon atoms, hydrogen atoms, and oxygen atoms, a halogenated hydrocarbon group, a group consisting of carbon atoms, oxygen atoms, and halogen atoms, and a group consisting of carbon atoms, hydrogen atoms, oxygen atoms, and halogen atoms are preferred. When the organic group is a hydrocarbon group, the hydrocarbon group may be an aromatic hydrocarbon group, an aliphatic hydrocarbon group, or a group containing an aromatic skeleton and an aliphatic skeleton. The number of carbon atoms in the organic group is preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 5.

Specific examples of hydrocarbon groups include chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-icosyl; vinyl, 1-propenyl, 2-n-propenyl (allyl), and 1-n-butenyl. , 2-n-butenyl, and 3-n-butenyl; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, o-tolyl, m-tolyl, p-tolyl, α-naphthyl, β-naphthyl, biphenyl-4-yl, biphenyl-3-yl, biphenyl-2-yl, anthryl, and phenanthryl; and aralkyl groups such as benzyl, phenethyl, α-naphthylmethyl, β-naphthylmethyl, α-naphthylethyl, and β-naphthylethyl.

Specific examples of halogenated hydrocarbon groups include halogenated chain alkyl groups such as chloromethyl, dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl, tribromomethyl, fluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, heptafluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl, perfluorooctyl, perfluorononyl, and perfluorodecyl; halogenated cyclohexyl groups such as 2-chlorocyclohexyl, 3-chlorocyclohexyl, 4-chlorocyclohexyl, 2,4-dichlorocyclohexyl, 2-bromocyclohexyl, 3-bromocyclohexyl, and 4-bromocyclohexyl. Chloroalkyl groups; halogenated aryl groups such as 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 2,6-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 2-bromophenyl group, 3-bromophenyl group, 4-bromophenyl group, 2-fluorophenyl group, 3-fluorophenyl group, and 4-fluorophenyl group; halogenated aralkyl groups such as 2-chlorophenylmethyl group, 3-chlorophenylmethyl group, 4-chlorophenylmethyl group, 2-bromophenylmethyl group, 3-bromophenylmethyl group, 4-bromophenylmethyl group, 2-fluorophenylmethyl group, 3-fluorophenylmethyl group, and 4-fluorophenylmethyl group.

Specific examples of groups consisting of carbon atoms, hydrogen atoms, and oxygen atoms include hydroxyl chain alkyl groups such as hydroxymethyl groups, 2-hydroxyethyl groups, 3-hydroxy-n-propyl groups, and 4-hydroxy-n-butyl groups; halogenated cycloalkyl groups such as 2-hydroxycyclohexyl groups, 3-hydroxycyclohexyl groups, and 4-hydroxycyclohexyl groups; 2-hydroxyphenyl groups, 3-hydroxyphenyl groups, 4-hydroxyphenyl groups, 2,3-dihydroxyphenyl groups, 2,4-dihydroxyphenyl groups, 2,5-dihydroxyphenyl groups, hydroxyaryl groups such as 2-hydroxyphenylmethyl group, 3-hydroxyphenylmethyl group, and 4-hydroxyphenylmethyl group; hydroxyaralkyl groups such as 2-hydroxyphenylmethyl group, 3-hydroxyphenylmethyl group, and 4-hydroxyphenylmethyl group; methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butyloxy group, isobutyloxy group, sec-butyloxy group, tert-butyloxy group, n-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, chain alkoxy groups such as n-alkyloxy, 2-ethylhexyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy, n-octadecyloxy, n-nonadecyloxy, and n-icosyloxy; chain alkoxy groups such as n-alkyloxy, 2-n-alkyloxy, 2-n-alkyloxy, 2-n-alkyloxy, 2-n-alkyloxy, and 2-n-alkyloxy; chain alkenyloxy groups such as a phenyloxy group; aryloxy groups such as a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, an α-naphthyloxy group, a β-naphthyloxy group, a biphenyl-4-yloxy group, a biphenyl-3-yloxy group, a biphenyl-2-yloxy group, an anthryloxy group, and a phenanthryloxy group; aralkyloxy groups such as a benzyloxy group, a phenethyloxy group, an α-naphthylmethyloxy group, a β-naphthylmethyloxy group, an α-naphthylethyloxy group, and a β-naphthylethyloxy group; alkoxyalkyl groups such as an alkoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, a 2-methoxyethyl group, a 2-ethoxyethyl group, a 2-n-propoxyethyl group, a 3-methoxy-n-propyl group, a 3-ethoxy-n-propyl group, a 3-n-propoxy-n-propyl group, a 4-methoxy-n-butyl group, a 4-ethoxy-n-butyl group, and a 4-n-propoxy-n-butyl group; a methoxymethoxy group, an ethoxymethoxy group, an n-propoxymethoxy group, a 2-methoxyethoxy group, a 2-ethoxyethoxy group, a 2-n-propoxyethoxy group, a 3 -alkoxyalkoxy groups such as methoxy-n-propoxy group, 3-ethoxy-n-propoxy group, 3-n-propoxy-n-propoxy group, 4-methoxy-n-butyloxy group, 4-ethoxy-n-butyloxy group, and 4-n-propoxy-n-butyloxy group; alkoxyaryl groups such as 2-methoxyphenyl group, 3-methoxyphenyl group, and 4-methoxyphenyl group; alkoxyaryloxy groups such as 2-methoxyphenoxy group, 3-methoxyphenoxy group, and 4-methoxyphenoxy group; formyl group, acetyl group, propionyl group aliphatic acyl groups such as butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, nonanoyl, and decanoyl groups; aromatic acyl groups such as benzoyl, α-naphthoyl, and β-naphthoyl groups; methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butyloxycarbonyl, n-pentyloxycarbonyl, n-hexylcarbonyl, n-heptyloxycarbonyl, n-octyloxycarbonyl, n-nonyloxycarbonyl, and n-decyloxycarbonyl groups. chain alkyloxycarbonyl groups such as; aryloxycarbonyl groups such as phenoxycarbonyl, α-naphthoxycarbonyl, and β-naphthoxycarbonyl groups; aliphatic acyloxy groups such as formyloxy, acetyloxy, propionyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy, and decanoyloxy groups; and aromatic acyloxy groups such as benzoyloxy, α-naphthoyloxy, and β-naphthoyloxy groups.

It is preferable that R ^a01 to R ^a018 are each independently a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having from 1 to 5 carbon atoms, and an alkoxy group having from 1 to 5 carbon atoms. It is more preferable that R ^a01 to R ^a018 are all hydrogen atoms, as this makes it easier to form a cured film having particularly excellent mechanical properties.

In formulae (a01-2) to (a01-5), R ^a01 to R ^a018 are the same as R ^a01 to R ^a018 in formula (a01-1). Examples of the divalent group formed when R ^a02 and R ^a010 are bonded to each other in formulae (a01-2) and (a01-4), when R ^a013 and R ^a016 are bonded to each other in formula (a01-2), and when R ^a02 and R ^a08 are bonded to each other in formula (a01-3) include -CH ₂ - and -C(CH ₃ ) ₂ -.

Among the alicyclic epoxy compounds represented by formula (a01-1), specific examples of suitable compounds include alicyclic epoxy compounds represented by the following formulas (a01-1a), (a01-1b), and (a01-1c), 2,2-bis(3,4-epoxycyclohexyl-1-yl)propane [=2,2-bis(3,4-epoxycyclohexyl)propane], and the like.

Among the alicyclic epoxy compounds represented by formula (a01-2), specific examples of suitable compounds include alicyclic epoxy compounds represented by the following formulas (a01-2a) and (a01-2b).

Of the alicyclic epoxy compounds represented by formula (a01-3), specific examples of suitable compounds include S spiro[3-oxatricyclo[3.2.1.0 ^2,4 ]octane-6,2′-oxirane].

Specific examples of suitable compounds among the alicyclic epoxy compounds represented by formula (a01-4) include 4-vinylcyclohexene dioxide, dipentene dioxide, limonene dioxide, 1-methyl-4-(3-methyloxiran-2-yl)-7-oxabicyclo[4.1.0]heptane, etc.

Among the alicyclic epoxy compounds represented by formula (a01-5), specific examples of suitable compounds include 1,2,5,6-diepoxycyclooctane, etc.

（式（ａ１－Ｉ）中、Ｘ^ａ１、Ｘ^ａ２、及びＸ^ａ３は、それぞれ独立に、水素原子、又はエポキシ基を含んでいてもよい有機基であり、Ｘ^ａ１、Ｘ^ａ２、及びＸ^ａ３が有するエポキシ基の総数が２以上である。） Furthermore, a compound represented by the following formula (a1-I) can be suitably used as an epoxy resin precursor.

(In formula (a1-I), X ^a1 , X ^a2 , and X ^a3 each independently represent a hydrogen atom or an organic group which may contain an epoxy group, and the total number of epoxy groups contained in X ^a1 , X ^a2 , and X ^a3 is 2 or more.)

（式（ａ１－ＩＩ）中、Ｒ^ａ２０～Ｒ^ａ２２は、直鎖状、分岐鎖状又は環状のアルキレン基、アリーレン基、－Ｏ－、－Ｃ（＝Ｏ）－、－ＮＨ－及びこれらの組み合わせからなる基であり、それぞれ同一であってもよいし、異なっていてもよい。Ｅ^１～Ｅ^３は、エポキシ基、オキセタニル基、エチレン性不飽和基、アルコキシシリル基、イソシアネート基、ブロックイソシアネート基、チオール基、カルボキシ基、水酸基及びコハク酸無水物基からなる群より選択される少なくとも１種の置換基又は水素原子である。ただし、Ｅ^１～Ｅ^３のうち少なくとも２つは、エポキシ基及びオキセタニル基からなる群より選択される少なくとも１種である。） As the compound represented by the above formula (a1-I), a compound represented by the following formula (a1-II) is preferable.

(In formula (a1-II), R ^a20 to R ^a22 each represent a linear, branched or cyclic alkylene group, an arylene group, -O-, -C(=O)-, -NH-, or a group consisting of a combination thereof, and may be the same or different. E ¹ to E ³ each represent at least one substituent selected from the group consisting of an epoxy group, an oxetanyl group, an ethylenically unsaturated group, an alkoxysilyl group, an isocyanate group, a blocked isocyanate group, a thiol group, a carboxy group, a hydroxyl group, and a succinic anhydride group, or a hydrogen atom, with the proviso that at least two of E ¹ to E ³ each represent at least one selected from the group consisting of an epoxy group and an oxetanyl group.)

In formula (a1-II), for example, at least two of the groups represented by R ^a20 and E ¹ , R ^a21 and E ² , and R ^a22 and E ³ are preferably groups represented by the following formula (a1-IIa), and it is more preferable that all of them are groups represented by the following formula (a1-IIa). It is preferable that multiple groups represented by formula (a1-IIa) bonded to one compound are the same group.
-LC ^a (a1-IIa)
(In formula (a1-IIa), L is a linear, branched or cyclic alkylene group, an arylene group, -O-, -C(=O)-, -NH- or a group consisting of a combination thereof, and C ^a is an epoxy group. In formula (a1-IIa), L and C ^a may be bonded to form a cyclic structure.)

In formula (a1-IIa), the linear, branched or cyclic alkylene group represented by L is preferably an alkylene group having 1 to 10 carbon atoms, and the arylene group represented by L is preferably an arylene group having 5 to 10 carbon atoms. In formula (a1-IIa), L is preferably a linear alkylene group having 1 to 3 carbon atoms, a phenylene group, -O-, -C(=O)-, -NH-, or a group consisting of a combination thereof, and is preferably at least one of a linear alkylene group having 1 to 3 carbon atoms, such as a methylene group, and a phenylene group, or a group consisting of a combination of these with at least one of -O-, -C(=O)-, and NH-.

（式（ａ１－ＩＩｂ）中、Ｒ^ａ２３は、水素原子又はメチル基である。） In formula (a1-IIa), examples of the case where L and ^Ca are bonded to form a cyclic structure include, for example, the case where a branched alkylene group and an epoxy group are bonded to form a cyclic structure (a structure having an alicyclic epoxy group), and organic groups represented by the following formulas (a1-IIb) to (a1-IId) can be mentioned.

(In formula (a1-IIb), R ^a23 is a hydrogen atom or a methyl group.)

Examples of the compound represented by formula (a1-II) include, but are not limited to, epoxy compounds having an oxiranyl group or an alicyclic epoxy group.

In addition, a siloxane compound having two or more glycidyl groups in the molecule (hereinafter, simply referred to as a "siloxane compound") can be suitably used as an epoxy resin precursor.

The siloxane compound is a compound having a siloxane skeleton constituted by siloxane bonds (Si--O--Si) and two or more glycidyl groups in the molecule.
Examples of the siloxane skeleton in the siloxane compound include a cyclic siloxane skeleton and a cage-type or ladder-type polysilsesquioxane skeleton.

As the siloxane compound, a compound having a cyclic siloxane skeleton represented by the following formula (a1-III) (hereinafter, sometimes referred to as "cyclic siloxane") is preferable.

In formula (a1-III), R ^a24 and R ^a25 represent a monovalent group or alkyl group containing an epoxy group. However, of x1 R ^a24s and x1 R ^a25s in the compound represented by formula (a1-III), at least two are monovalent groups containing an epoxy group. Furthermore, x1 in formula (a1-III) represents an integer of 3 or more. In addition, R ^a24 and R ^a25 in the compound represented by formula (a1-III) may be the same or different. Furthermore, multiple R ^a24s may be the same or different. Multiple R ^a25s may also be the same or different.
Examples of the alkyl group include linear or branched alkyl groups having 1 to 18 carbon atoms (preferably 1 to 6 carbon atoms, particularly preferably 1 to 3 carbon atoms), such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

In formula (a1-III), x1 represents an integer of 3 or more, and preferably an integer of 3 to 6 in terms of excellent crosslinking reactivity when forming a cured film.

The number of epoxy groups in the siloxane compound molecule is 2 or more, and from the viewpoint of excellent crosslinking reactivity when forming a cured film, 2 to 6 is preferable, and 2 to 4 is particularly preferable.

（上記式（ａ１－ＩＩＩａ）及び式（ａ１－ＩＩＩｂ）中、Ｄ^１及びＤ^２は、それぞれ独立にアルキレン基を表し、ｍｓは０以上２以下の整数を表す。） The monovalent group containing an epoxy group is preferably an alicyclic epoxy group or a glycidyl ether group represented by -D-O-R ^a26 [D represents an alkylene group, and R ^a26 represents a glycidyl group], more preferably an alicyclic epoxy group, and even more preferably an alicyclic epoxy group represented by the following formula (a1-IIIa) or (a1-IIIb). Examples of D (alkylene group) include linear or branched alkylene groups having 1 to 18 carbon atoms, such as a methylene group, a methylmethylene group, a dimethylmethylene group, a dimethylene group, and a trimethylene group.

(In the above formula (a1-IIIa) and formula (a1-IIIb), ^D1 and ^D2 each independently represent an alkylene group, and ms represents an integer of 0 to 2.)

The metal oxide microparticle dispersion may contain, as an epoxy resin precursor, a compound having a siloxane skeleton, such as an alicyclic epoxy group-containing cyclic siloxane, an alicyclic epoxy group-containing silicone resin described in JP-A-2008-248169, and an organopolysilsesquioxane resin having at least two epoxy functional groups in one molecule described in JP-A-2008-19422, in addition to the siloxane compound represented by formula (a1-III).

Specific examples of siloxane compounds include cyclic siloxanes having two or more glycidyl groups in the molecule, as shown in the following formula. In addition, examples of siloxane compounds that can be used include commercially available products under the trade names "X-40-2670", "X-40-2701", "X-40-2728", "X-40-2738", and "X-40-2740" (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[Precursor resin]
The base component (B) is preferably a precursor resin that undergoes an aromatic ring formation reaction within a molecule and/or a crosslinking reaction between molecules upon heating. Also preferred as the base component (B) are precursor resins that give a cured product upon baking.

By the aromatic ring formation reaction within a molecule, the structure of the molecular chains constituting the resin becomes rigid, and a metal oxide-containing film having excellent heat resistance and mechanical properties can be formed. Among the aromatic ring formation reactions within a molecule, preferred reactions include, for example, the reactions shown in the following formulas (I) to (VI). Note that the reaction in the following formula is merely one example of an aromatic ring formation reaction, and the structure of the resin used as the base component (B) that causes an aromatic ring formation reaction within a molecule when heated is not limited to the structure of the precursor polymer shown in the following formula.

(Resin having a group selected from a hydroxyl group, a carboxylic anhydride group, a carboxyl group, and an epoxy group in the molecule)
Intramolecular crosslinking causes molecular chains constituting the resin to crosslink with each other to form a three-dimensional crosslinked structure. Therefore, when a resin having a group selected from a hydroxyl group, a carboxylic anhydride group, a carboxyl group, and an epoxy group in the molecule, which causes a crosslinking reaction by heating, is used as the base component (B), a metal oxide-containing film having excellent heat resistance and mechanical properties can be obtained.

When a resin containing hydroxyl groups is used, the action of the dehydrating condensing agent causes crosslinking between the molecules contained in the resin through dehydrating condensation between the hydroxyl groups. In addition, since hydroxyl groups contain active hydrogen atoms and are highly reactive, they react with various crosslinking agents to give a cured product containing crosslinked resin.

When a resin having a carboxylic acid anhydride group is used, the carboxyl groups generated by hydrolysis of the acid anhydride group undergo dehydration condensation and crosslinking due to the action of a dehydration condensing agent. In addition, since the acid anhydride group itself is highly reactive, a cured product containing a crosslinked resin can be obtained by using a crosslinking agent such as a polyol having two or more hydroxyl groups or a polyamine having two or more amino groups.

When a resin containing carboxy groups is used, the action of the dehydrating condensing agent causes crosslinking between the molecules contained in the resin through dehydrating condensation between the carboxy groups. Crosslinking can also be achieved using a crosslinking agent that has a functional group that can react with a carboxy group, such as an isocyanate group.

When using a resin containing epoxy groups, a well-known curing accelerator can be used as necessary to cause crosslinking between the molecules contained in the resin through a polyaddition reaction between the epoxy groups.

An example of a resin having a hydroxyl group in the molecule is a novolac resin. There is no particular limitation on the novolac resin, but a resin obtained by condensing a condensing agent such as formaldehyde or paraformaldehyde in a ratio of 0.5 mol to 1.0 mol per 1 mol of phenols under an acid catalyst is preferred.

Examples of phenols include cresols such as phenol, o-cresol, m-cresol, and p-cresol; xylenols such as 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, o-butylphenol, m-butylphenol, p-butylphenol, and p-tert-butylphenol. Examples of the phenol include alkylphenols such as 2,3,5-trimethylphenol and 3,4,5-trimethylphenol; trialkylphenols such as resorcinol, catechol, hydroquinone, hydroquinone monomethyl ether, pyrogallol, and phloroglucinol; polyhydric phenols such as alkylresorcinol, alkylcatechol, and alkylalkylhydroquinone (the number of carbon atoms in the alkyl group contained in the alkyl polyhydric phenol is 1 to 4), α-naphthol, β-naphthol, hydroxydiphenyl, and bisphenol A. These phenols can be used alone or in combination of two or more.

Among phenols, m-cresol and p-cresol are preferred, and it is more preferred to use m-cresol and p-cresol in combination. By adjusting the blending ratio of the two, it is possible to adjust various properties as a photoresist, such as sensitivity and heat resistance. The blending ratio of m-cresol and p-cresol is not particularly limited, but it is preferable for m-cresol/p-cresol to be 3/7 or more and 8/2 or less (mass ratio). If the ratio of m-cresol is less than the lower limit above, the sensitivity may decrease, and if it exceeds the upper limit above, the heat resistance may decrease.

Examples of acid catalysts used in the production of novolac resins include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and phosphorous acid, organic acids such as formic acid, oxalic acid, acetic acid, diethyl sulfate, and paratoluenesulfonic acid, and metal salts such as zinc acetate. These acid catalysts can be used alone or in combination of two or more.

The mass average molecular weight of the novolac resin, calculated as polystyrene by gel permeation chromatography (GPC), is preferably 1,000 or more and 50,000 or less.

As a resin having a carboxylic anhydride group in the molecule, a copolymer obtained by polymerizing a mixture of monomers having an unsaturated double bond, including one or more monomers selected from maleic anhydride, citraconic anhydride, and itaconic anhydride, is preferred. As such a polymer, a styrene-maleic acid copolymer is preferred.

As the resin having a carboxy group in the molecule, a resin obtained by hydrolyzing an acid anhydride group in the above-mentioned resin having a carboxylic acid anhydride group in the molecule, or a copolymer obtained by polymerizing a mixture of monomers having an unsaturated double bond, including one or more monomers selected from (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid, is preferable.

Epoxy-containing resins, which have epoxy groups in their molecules, will be described in detail later.

Among compounds that undergo intramolecular aromatic ring formation reactions or intermolecular crosslinking reactions upon heating, polyamic acid, polybenzoxazole precursors, polybenzothiazole precursors, polybenzimidazole precursors, styrene-maleic acid copolymers, and epoxy group-containing resins are preferred because they are likely to form metal oxide-containing films with excellent heat resistance.

[Polyimide resin precursor]
An example of a polyimide resin precursor is polyamic acid. After forming a film from a metal oxide microparticle dispersion liquid containing polyamic acid as the base component (B), the film formed is heated, if necessary in the presence of an imidizing agent, to form a metal oxide-containing film containing a polyimide resin and having excellent heat resistance.

The molecular weight of the polyamic acid is preferably, in terms of mass average molecular weight, from 5,000 to 30,000, and more preferably from 10,000 to 20,000. When a polyamic acid having a mass average molecular weight within this range is used, a metal oxide-containing film having excellent heat resistance is easily formed.
A suitable polyamic acid is, for example, a polyamic acid having a structural unit represented by the following formula (A1).

（式（Ａ１）中、Ｒ^ａ０２０は４価の有機基であり、Ｒ^ａ０２１は２価の有機基であり、ｎ^ａは式（Ａ１）で表される構成単位の繰り返し数である。）

(In formula (A1), R ^a020 is a tetravalent organic group, R ^a021 is a divalent organic group, and n ^a is the repeating number of the structural unit represented by formula (A1).)

In formula (A1), the number of carbon atoms of R ^a020 and R ^a021 is preferably 2 to 50, more preferably 2 to 30. R ^a020 and R ^a021 may each be an aliphatic group, an aromatic group, or a group that combines these structures. The tetravalent aromatic group is the same as R ^a022 described below. R ^a020 and R ^a021 may contain a halogen atom, an oxygen atom, and a sulfur atom in addition to a carbon atom and a hydrogen atom. When R ^a020 and R ^a021 contain an oxygen atom, a nitrogen atom, or a sulfur atom, the oxygen atom, nitrogen atom, or sulfur atom may be contained in R a020 and R a021 as a nitrogen-containing heterocyclic group, a group selected from -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO ₂ -, -S-, and -S-S-, and it is more preferable that the oxygen atom, nitrogen atom, or sulfur atom is contained in R ^a020 and R ^a021 as a group selected from -O-, -CO-, -SO-, -SO ₂ -, ^-S- , and -S ^- S-.

Polyamic acid is usually prepared by reacting a tetracarboxylic dianhydride component with a diamine component. Below, we will explain the tetracarboxylic dianhydride component, diamine component, and polyamic acid manufacturing method used in the preparation of polyamic acid.

（式（ａ１－０１）中、Ｒ^ａ０２０は式（Ａ１）のＲ^ａ０２０と同様である。） (Tetracarboxylic acid dianhydride component)
The tetracarboxylic dianhydride component serving as a raw material for synthesizing polyamic acid is not particularly limited as long as it can form polyamic acid by reacting with a diamine component. The tetracarboxylic dianhydride component can be appropriately selected from tetracarboxylic dianhydrides that have been used as raw materials for synthesizing polyamic acid. The tetracarboxylic dianhydride component may be an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride, and examples thereof include tetracarboxylic dianhydrides represented by the following formula (a1-01), with aromatic tetracarboxylic dianhydrides being preferred. Two or more types of tetracarboxylic dianhydride components may be used in combination.

(In formula (a1-01), R ^a020 is the same as R ^a020 in formula (A1).)

Specific examples of suitable aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride. Of these, 3,3',4,4'-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride are preferred in terms of price, availability, etc.

（式（ａ１－０２）中、Ｒ^ａ０２１は式（Ａ１）のＲ^ａ０２１と同様である。） (Diamine component)
The diamine component serving as a raw material for synthesizing the polyamic acid is not particularly limited as long as it can form a polyamic acid by reacting with the tetracarboxylic dianhydride component. The diamine component can be appropriately selected from diamines that have been conventionally used as raw materials for synthesizing polyamic acid, and examples thereof include a diamine component represented by the following formula (a1-02) and a diamine that gives ^Yd described below. The diamine component may be an aromatic diamine or an aliphatic diamine, but is preferably an aromatic diamine. Two or more diamine components may be used in combination.

(In formula (a1-02), R ^a021 is the same as R ^a021 in formula (A1).)

Specific examples of suitable aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylether, 3,4'-diaminodiphenylether, 3,3'-diaminodiphenylether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene Examples of suitable diamines include 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 9,9-bis(4-aminophenyl)-9H-fluorene, 9,9-bis(4-amino-3-methylphenyl)-9H-fluorene, and 4,4'-[1,4-phenylenebis(1-methylethane-1,1-diyl)]dianiline. Among these, p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, and 4,4'-diaminodiphenyl ether are preferred in terms of price, availability, and the like.

(Method for producing polyamic acid)
The polyamic acid is obtained by reacting the tetracarboxylic dianhydride component and the diamine component described above in a solvent capable of dissolving both of them. The amounts of the tetracarboxylic dianhydride component and the diamine component used when synthesizing the polyamic acid are not particularly limited. The diamine component is preferably used in an amount of 0.50 mol to 1.50 mol, more preferably 0.60 mol to 1.30 mol, and particularly preferably 0.70 mol to 1.20 mol, per mol of the tetracarboxylic dianhydride component.

Examples of solvents that can be used in the synthesis of polyamic acid include aprotic polar organic solvents such as N,N,N',N'-tetramethylurea, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, and γ-butyrolactone, and glycol ethers such as diethylene glycol dialkyl ether, ethylene glycol monoalkyl ether acetate, diethylene glycol monoalkyl ether acetate, propylene glycol monoalkyl ether acetate, and propylene glycol monoalkyl ether propionate. Two or more of these solvents can be used in combination. Of these, it is preferable to use N,N,N',N'-tetramethylurea.

The amount of solvent used when synthesizing polyamic acid is not particularly limited as long as polyamic acid of the desired molecular weight can be synthesized. Typically, the amount of solvent used is preferably 100 parts by mass or more and 4000 parts by mass or less, and more preferably 150 parts by mass or more and 2000 parts by mass or less, relative to 100 parts by mass of the total amount of the tetracarboxylic dianhydride component and the diamine component.

The temperature at which the tetracarboxylic dianhydride component and the diamine component are reacted is not particularly limited as long as the reaction proceeds well. Typically, the reaction temperature between the tetracarboxylic dianhydride component and the diamine component is preferably from -5°C to 150°C, more preferably from 0°C to 120°C, and particularly preferably from 0°C to 70°C. The time for reacting the tetracarboxylic dianhydride component and the diamine component varies depending on the reaction temperature, but is typically preferably from 1 hour to 50 hours, more preferably from 2 hours to 40 hours, and particularly preferably from 5 hours to 30 hours.

According to the above method, a solution or paste of polyamic acid is obtained. Such a solution or paste may be used as is for preparing a metal oxide microparticle dispersion liquid. In addition, a solid polyamic acid obtained by removing the solvent from the polyamic acid solution or paste may be used for preparing a metal oxide microparticle dispersion liquid.

[Polybenzoxazole precursor]
Polybenzoxazole precursor is typically produced by reacting aromatic diamine diol with a dicarbonyl compound having a specific structure. The aromatic diamine diol, the dicarbonyl compound, the solvent used in the synthesis of polybenzoxazole precursor, and the method for producing polybenzoxazole precursor are described below.

（式（ａ０２）中、Ｒ^ａ０２２は１以上の芳香環を含む４価の有機基であり、式（ａ０２）で表される芳香族ジアミンジオールに含まれる２組のアミノ基と水酸基との組み合わせに関して、それぞれの組み合わせでは、アミノ基と水酸基とは、Ｒ^ａ０２２に含まれる芳香環上の隣接する２つの炭素原子に結合している。） (Aromatic diamine diol)
As the aromatic diamine diol, those that have been used in the synthesis of polybenzoxazole can be used without any particular limitation. As the aromatic diamine diol, it is preferable to use a compound represented by the following formula (a02). As the aromatic diamine diol, one type may be used alone, or two or more types may be used in combination.

(In formula (a02), R ^a022 is a tetravalent organic group containing one or more aromatic rings, and in each of the two combinations of amino groups and hydroxyl groups contained in the aromatic diamine diol represented by formula (a02), the amino group and the hydroxyl group are bonded to two adjacent carbon atoms on the aromatic ring contained in R ^a022 .)

In formula (a02), R ^a022 is a tetravalent organic group containing one or more aromatic rings, and the number of carbon atoms is preferably 6 to 50, more preferably 6 to 30. R ^a022 may be an aromatic group, or may be a group in which two or more aromatic groups are bonded via a bond containing an aliphatic hydrocarbon group, a halogenated aliphatic hydrocarbon group, or a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Examples of bonds containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom contained in R ^a022 include -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO ₂ -, -S-, and -S-S-, and -O-, -CO-, -SO-, -SO ₂ -, -S-, and -S-S- are preferred.

The aromatic ring contained in R ^a022 may be an aromatic heterocycle. The aromatic ring bonded to the amino group and hydroxyl group in R ^a022 is preferably a benzene ring. When the ring bonded to the amino group and hydroxyl group in R ^a022 is a condensed ring containing two or more rings, the ring bonded to the amino group and hydroxyl group in the condensed ring is preferably a benzene ring.

（式（ａ０２－１）中、Ｘ^０１は、炭素原子数１～１０のアルキレン基、炭素原子数１～１０のフッ素化アルキレン基、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及び単結合からなる群より選択される１種である。式（ａ０２－２）～（ａ０２－５）中、Ｙ^０１は、それぞれ、同一でも異なっていてもよく、－ＣＨ_２－、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、及び単結合からなる群より選択される１種である。） Preferred examples of R ^a022 include groups represented by the following formulas (a02-1) to (a02-9).

(In formula (a02-1), X ⁰¹ is one selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, a fluorinated alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CO-, -COO-, -CONH-, and a single bond. In formulas (a02-2) to (a02-5), Y ⁰¹ may be the same or different and is one selected from the group consisting of -CH ₂ -, -O-, -S-, -SO-, -SO ₂ -, -CO-, and a single bond.)

The groups represented by the above formulae (a02-1) to (a02-9) may have one or more substituents on the aromatic ring. Preferred examples of the substituent include a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a fluorinated alkyl group having 1 to 6 carbon atoms, and a fluorinated alkoxy group having 1 to 6 carbon atoms. When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferably a perfluoroalkyl group or a perfluoroalkoxy group.

Specific examples of the compound represented by the above formula (a02) include 2,4-diamino-1,5-benzenediol, 2,5-diamino-1,4-benzenediol, 2,5-diamino-3-fluoro-1,4-benzenediol, 2,5-diamino-3,6-difluoro-1,4-benzenediol, 2,6-diamino-1,5-dihydroxynaphthalene, 1,5-diamino-2,6-dihydroxynaphthalene, 2,6-diamino-3,7-dihydroxynaphthalene, 1,6-diamino-2,5-dihydroxynaphthalene, 4,4'-diamino-3,3' -dihydroxybiphenyl, 3,3'-diamino-4,4'-dihydroxybiphenyl, 2,3'-diamino-3,2'-dihydroxybiphenyl, 3,4'-diamino-4,3'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dihydroxy-6,6'-ditrifluoromethylbiphenyl, 3,3'-diamino-4,4'-dihydroxy-6,6'-ditrifluoromethylbiphenyl, 2,3'-diamino-3,2'-dihydroxy-6,6'-ditrifluoromethylbiphenyl, 3,4'-diamino-4,3'-dihydroxy -6,6'-ditrifluoromethylbiphenyl, 4,4'-diamino-3,3'-dihydroxy-5,5'-ditrifluoromethylbiphenyl, 3,3'-diamino-4,4'-dihydroxy-5,5'-ditrifluoromethylbiphenyl, 2,3'-diamino-3,2'-dihydroxy-5,5'-ditrifluoromethylbiphenyl, 3,4'-diamino-4,3'-dihydroxy-5,5'-ditrifluoromethylbiphenyl, bis(4-amino-3-hydroxyphenyl)methane, bis(3-amino-4-hydroxyphenyl)methane, 3,4'-diamino-4,3'-dihydroxydiphenylmethane, bis(4-amino-3-hydroxy-6-trifluoromethyl)methane, bis(3-amino-4-hydroxy-6-trifluoromethyl)methane, 3,4'-diamino-4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenylmethane, bis(4-amino-3-hydroxyphenyl)difluoromethane, bis(3-amino-4-hydroxyphenyl)difluoromethane, 3,4'-diamino-4,3'-dihydroxydiphenyldifluoromethane, bis(4-amino bis(3-amino-4-hydroxy-6-trifluoromethylphenyl)difluoromethane, 3,4'-diamino-4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenyldifluoromethane, bis(4-amino-3-hydroxyphenyl)ether, bis(3-amino-4-hydroxyphenyl)ether, 3,4'-diamino-4,3'-dihydroxydiphenylether, bis(4-amino-3-hydroxy-6-trifluoromethylphenyl)ether ether, bis(3-amino-4-hydroxy-6-trifluoromethylphenyl)ether, 3,4'-diamino-4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenyl ether, bis(4-amino-3-hydroxyphenyl)ketone, bis(3-amino-4-hydroxyphenyl)ketone, 3,4'-diamino-4,3'-dihydroxydiphenyl ketone, bis(4-amino-3-hydroxy-6-trifluoromethyl)ketone, bis(3-amino-4-hydroxy-6-trifluoromethyl)ketone, 3,4'-diamino -4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenyl ketone, 2,2-bis(4-amino-3-hydroxyphenyl)propane, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2-(3-amino-4-hydroxyphenyl)-2-(4'-amino-3'-hydroxyphenyl)propane, 2,2-bis(4-amino-3-hydroxy-6-trifluoromethylphenyl)propane, 2,2-bis(3-amino-4-hydroxy-6-trifluoromethylphenyl)propane, 2-(3-amino-4-hydroxy- 2,2-bis(3-amino-4-hydroxy-5-trifluoromethylphenyl)propane, 2,2-bis(4-amino-3-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2-(3-amino-4-hydroxyphenyl)-2-(4'-amino-3'-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-amino-3-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxy-6-trifluoromethylphenyl)hexafluoropropane, 2-(3-amino-4-hydroxy-6-trifluoromethylphenyl)-2-(4'-amino-3'-hydroxy-6'-trifluoromethylphenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxy-5-trifluoromethylphenyl)hexafluoropropane, bis(4-amino-3-hydroxyphenyl)sulfone , bis(3-amino-4-hydroxyphenyl)sulfone, 3,4'-diamino-4,3'-dihydroxydiphenyl sulfone, bis(4-amino-3-hydroxy-6-trifluoromethyl)sulfone, bis(3-amino-4-hydroxy-6-trifluoromethyl)sulfone, 3,4'-diamino-4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenyl sulfone, bis(4-amino-3-hydroxyphenyl)sulfide, bis(3-amino-4-hydroxyphenyl)sulfide, 3,4'-diamino-4,3'-dihy hydroxydiphenyl sulfide, bis(4-amino-3-hydroxy-6-trifluoromethyl) sulfide, bis(3-amino-4-hydroxy-6-trifluoromethyl) sulfide, 3,4'-diamino-4,3'-dihydroxy-6,6'-ditrifluoromethyldiphenyl sulfide, (4-amino-3-hydroxyphenyl) 4-amino-3-hydroxyphenyl benzoate, (3-amino-4-hydroxyphenyl) 3-amino 4-hydroxyphenyl benzoate, (3-amino-4-hydroxyphenyl) 4-amino-3 -hydroxyphenyl benzoate, (4-amino-3-hydroxyphenyl) 3-amino-4-hydroxyphenyl benzoate, N-(4-amino-3-hydroxyphenyl) 4-amino-3-hydroxybenzamide, N-(3-amino-4-hydroxyphenyl) 3-amino-4-hydroxyphenyl benzamide, N-(3-amino-4-hydroxyphenyl) 4-amino-3-hydroxyphenyl benzamide, N-(4-amino-3-hydroxyphenyl) 3-amino-4-hydroxyphenyl benzamide, 2,4'-bis(4- 4,4'-bis(4-amino-3-hydroxyphenoxy)biphenyl, 2,4'-bis(3-amino-4-hydroxyphenoxy)biphenyl, 4,4'-bis(4-amino-3-hydroxyphenoxy)biphenyl, 4,4'-bis(3-amino-4-hydroxyphenoxy)biphenyl, di[4-(4-amino-3-hydroxyphenoxy)phenyl]ether, di[4-(3-amino-4-hydroxyphenoxy)phenyl]ether, 2,4'-bis(4-amino-3-hydroxyphenoxy)benzophenone, 2,4'-bis(3-amino-4-hydroxyphenoxy)biphenyl, 4,4'-bis(4-amino-3-hydroxyphenoxy)benzophenone, 4,4'-bis(3-amino-4-hydroxyphenoxy)benzophenone, 2,4'-bis(4-amino-3-hydroxyphenoxy)octafluorobiphenyl, 2,4'-bis(3-amino-4-hydroxyphenoxy)octafluorobiphenyl, 4,4'-bis(4-amino-3-hydroxyphenoxy)octafluorobiphenyl, 4,4'-bis(3-amino-4-hydroxyphenoxy)octafluorobiphenyl , 2,4'-bis(4-amino-3-hydroxyphenoxy)octafluorobenzophenone, 2,4'-bis(3-amino-4-hydroxyphenoxy)octafluorobenzophenone, 4,4'-bis(4-amino-3-hydroxyphenoxy)octafluorobenzophenone, 4,4'-bis(3-amino-4-hydroxyphenoxy)octafluorobenzophenone, 2,2-bis[4-(4-amino-3-hydroxyphenoxy)phenyl]propane, 2,2-bis[4-(3-amino-4-hydroxyphenoxy)phenyl]propane Pan, 2,2-bis[4-(4-amino-3-hydroxyphenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(3-amino-4-hydroxyphenoxy)phenyl]hexafluoropropane, 2,8-diamino-3,7-dihydroxydibenzofuran, 2,8-diamino-3,7-dihydroxyfluorene, 2,6-diamino-3,7-dihydroxyxanthene, 9,9-bis-(4-amino-3-hydroxyphenyl)fluorene, and 9,9-bis-(3-amino-4-hydroxyphenyl)fluorene.

Of these, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is preferred.

(Dicarbonyl compounds)
As the synthesis raw materials of the polybenzoxazole precursor, the dicarbonyl compound represented by the following formula (a03) is used together with the aromatic diamine diol described above. The polybenzoxazole precursor is obtained by condensing the aromatic diamine diol and the dicarbonyl compound represented by the following formula (a03).

（式（ａ０３）中、Ｒ^ａ０２３は２価の有機基であり、Ａ^０は水素原子又はハロゲン原子を表す。）

(In formula (a03), R ^a023 represents a divalent organic group, and A ⁰ represents a hydrogen atom or a halogen atom.)

In formula (a03), R ^a023 may be an aromatic group, an aliphatic group, or a group that combines an aromatic group and an aliphatic group. In view of the fact that the heat resistance, mechanical properties, chemical resistance, etc. of the resulting polybenzoxazole resin are good, R ^a023 is preferably a group that contains an aromatic group and/or an alicyclic group. The aromatic group contained in R ^a023 may be an aromatic hydrocarbon group or an aromatic heterocyclic group.

R ^a023 may contain a halogen atom, an oxygen atom, or a sulfur atom in addition to a carbon atom and a hydrogen atom. When R ^{a023 contains an oxygen atom, a nitrogen atom, or a sulfur atom, the oxygen atom, nitrogen atom, or sulfur atom may be included in R a023} as a nitrogen-containing heterocyclic group, a group selected from -CONH-, -NH-, -N=N-, -CH=N-, -COO-, -O-, -CO-, -SO-, -SO 2 -, -S-, and -S-S-, and is more preferably included in R ^a023 as a group selected from _-O- , -CO-, -SO-, -SO ₂ -, -S-, and -S ^- S-.

In formula (a03), one of the two A ⁰ may be a hydrogen atom and the other may be a halogen atom, but it is preferable that both A 0 are hydrogen atoms or both A ^{0 are halogen atoms. When A 0 is} a halogen atom, A ⁰ is preferably chlorine, bromine, or iodine, and more preferably chlorine.

（式（Ａ２）中、Ｒ^ａ０２２及びＲ^ａ０２３は、式（ａ０２）及び式（ａ０３）と同様であり、ｎ^１は式（Ａ２）で表される単位の繰り返し数である。） When a dialdehyde compound in which both A ⁰ are hydrogen atoms is used as the dicarbonyl compound represented by formula (a03), a polybenzoxazole precursor represented by the following formula (A2) is produced.

(In formula (A2), R ^a022 and R ^a023 are the same as those in formulas (a02) and (a03), and ⁿ¹ is the number of repetitions of the unit represented by formula (A2).)

（式（Ａ３）中、Ｒ^ａ０２２及びＲ^ａ０２３は、式（ａ０２）及び式（ａ０３）と同様であり、ｎ^２は式（Ａ３）で表される単位の繰り返し数である。） When a dicarboxylic acid dihalide in which both A ⁰ are halogen atoms is used as the dicarbonyl compound represented by formula (a03), a polybenzoxazole precursor represented by the following formula (A3) is produced.

(In formula (A3), R ^a022 and R ^a023 are the same as those in formulas (a02) and (a03), and ⁿ² is the number of repetitions of the unit represented by formula (A3).)

The following describes dialdehyde compounds and dicarboxylic acid dihalides, which are suitable dicarbonyl compounds.

（式（ａ２－Ｉ）中、Ｒ^ａ０２３は、式（ａ０３）と同様である。） (Dialdehyde compounds)
The dialdehyde compound used as a raw material for the polybenzoxazole precursor is a compound represented by the following formula (a02-I): The dialdehyde compound may be used alone or in combination of two or more kinds.

(In formula (a2-I), R ^a023 is the same as in formula (a03).)

（上記式中、Ｘ^０２は、炭素原子数１以上１０以下のアルキレン基、炭素原子数１以上１０以下のフッ素化アルキレン基、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及び単結合からなる群より選択される１種である。Ｘ^０２が複数である場合、複数のＸ^０２は同一でも異なっていてもよい。Ｙ^０２は、それぞれ、同一でも異なっていてもよく、－ＣＨ_２－、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、及び単結合からなる群より選択される１種である。ｐ^０及びｑ^０は、それぞれ０～３の整数である。） Examples of the aromatic group or aromatic ring-containing group suitable for R ^a203 in formula (a2-I) include the following groups.

(In the above formula, X ⁰² is one type selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, a fluorinated alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CO-, -COO-, -CONH-, and a single bond. When there is a plurality of X ⁰² , the plurality of X ⁰² may be the same or different. Each Y ⁰² may be the same or different and is one type selected from the group consisting of -CH ₂ -, -O-, -S-, -SO-, -SO ₂ -, -CO-, and a single bond. p ⁰ and q ⁰ are each an integer of 0 to 3.)

（上記式中、Ｘ^０２は、炭素原子数１以上１０以下のアルキレン基、炭素原子数１以上１０以下のフッ素化アルキレン基、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及び単結合からなる群より選択される１種である。Ｘ^０２が複数である場合、複数のＸ^２は同一でも異なっていてもよい。Ｙ^０２は、それぞれ、同一でも異なっていてもよく、－ＣＨ_２－、－Ｏ－、－Ｓ－、－ＳＯ－、－ＳＯ_２－、－ＣＯ－、及び単結合からなる群より選択される１種である。Ｚ^０は、－ＣＨ_２－、－ＣＨ_２ＣＨ_２－、及び－ＣＨ＝ＣＨ－からなる群より選択される１種である。ｐ^０は、それぞれ０～３の整数である。） Examples of the alicyclic group or alicyclic-containing group suitable for R ^a023 in formula (a2-I) include the following groups.

(In the above formula, X ⁰² is one type selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, a fluorinated alkylene group having 1 to 10 carbon atoms, -O-, -S-, -SO-, -SO ₂ -, -CO-, -COO-, -CONH-, and a single bond. When there are multiple X ⁰² , the multiple X ² may be the same or different. Y ⁰² may be the same or different and is one type selected from the group consisting of -CH ₂ -, -O-, -S-, -SO-, -SO ₂ -, -CO-, and a single bond. Z ⁰ is one type selected from the group consisting of -CH ₂ -, -CH ₂ CH ₂ -, and -CH═CH-. Each p ⁰ is an integer of 0 to 3.)

The aromatic ring or alicyclic ring contained in the group suitable for R ^a023 may have one or more substituents on the ring. Preferred examples of the substituent include a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a fluorinated alkyl group having 1 to 6 carbon atoms, and a fluorinated alkoxy group having 1 to 6 carbon atoms. When the substituent is a fluorinated alkyl group or a fluorinated alkoxy group, it is preferably a perfluoroalkyl group or a perfluoroalkoxy group.

When the dialdehyde compound represented by formula (a2-I) is an aromatic dialdehyde, suitable examples thereof include benzenedialdehydes, pyridinedialdehydes, pyrazinedialdehydes, pyrimidinedialdehydes, naphthalenedialdehydes, biphenyldialdehydes, diphenyletherdialdehydes, diphenylsulfonedialdehydes, diphenylsulfidedialdehydes, bis(formylphenoxy)benzenes, [1,4-phenylenebis(1-methylethylidene)]bisbenzaldehydes, 2,2-bis[4-(formylphenoxy)phenyl]propanes, bis[4-(formylphenoxy)phenyl]sulfides, bis[4-(formylphenoxy)phenyl]sulfones, and fluorene-containing aldehydes.

Specific examples of benzenedialdehydes include phthalaldehyde, isophthalaldehyde, terephthalaldehyde, 3-fluorophthalaldehyde, 4-fluorophthalaldehyde, 2-fluoroisophthalaldehyde, 4-fluoroisophthalaldehyde, 5-fluoroisophthalaldehyde, 2-fluoroterephthalaldehyde, 3-trifluoromethylphthalaldehyde, 4-trifluoromethylphthalaldehyde, 2-trifluoromethylisophthalaldehyde, 4-trifluoromethylisophthalaldehyde, 5-trifluoromethylisophthalaldehyde, 2-trifluoromethylterephthalaldehyde, 3,4,5,6-tetrafluorophthalaldehyde, 2,4,5,6-tetrafluoroisophthalaldehyde, and 2,3,5,6-tetrafluoroterephthalaldehyde.

Specific examples of pyridine dialdehydes include pyridine-2,3-dialdehyde, pyridine-3,4-dialdehyde, and pyridine-3,5-dialdehyde.
Specific examples of pyrazine dialdehydes include pyrazine-2,3-dialdehyde, pyrazine-2,5-dialdehyde, and pyrazine-2,6-dialdehyde.
Specific examples of pyrimidine dialdehydes include pyrimidine-2,4-dialdehyde, pyrimidine-4,5-dialdehyde, and pyrimidine-4,6-dialdehyde.

Specific examples of naphthalene dialdehydes include naphthalene-1,5-dialdehyde, naphthalene-1,6-dialdehyde, naphthalene-2,6-dialdehyde, naphthalene-3,7-dialdehyde, 2,3,4,6,7,8-hexafluoronaphthalene-1,5-dialdehyde, 2,3,4,5,6,8-hexafluoronaphthalene-1,6-dialdehyde, 1,3,4,5,7,8-hexafluoronaphthalene-2,6-dialdehyde, 1-trifluoromethylnaphthalene-2,6-dialdehyde, 1,5-bis(trifluoromethyl)naphthalene-2,6-dialdehyde, and 1-trifluoromethyl These include naphthalene-3,7-dialdehyde, 1,5-bis(trifluoromethyl)naphthalene-3,7-dialdehyde, 1-trifluoromethyl-2,4,5,6,8-pentafluoronaphthalene-3,7-dialdehyde, 1-bis(trifluoromethyl)methoxy-2,4,5,6,8-pentafluoronaphthalene-3,7-dialdehyde, 1,5-bis(trifluoromethyl)-2,4,6,8-tetrafluoronaphthalene-3,7-dialdehyde, and 1,5-bis[bis(trifluoromethyl)methoxy]-2,4,6,8-tetrafluoronaphthalene-3,7-dialdehyde.

Specific examples of biphenyl dialdehydes include biphenyl-2,2'-dialdehyde, biphenyl-2,4'-dialdehyde, biphenyl-3,3'-dialdehyde, biphenyl-4,4'-dialdehyde, 6,6'-difluorobiphenyl-3,4'-dialdehyde, 6,6'-difluorobiphenyl-2,4'-dialdehyde, 6,6'-difluorobiphenyl-3,3'-dialdehyde, and 6,6'-difluorobiphenyl-3,4'-dialdehyde. , 6,6'-difluorobiphenyl-4,4'-dialdehyde, 6,6'-ditrifluoromethylbiphenyl-2,2'-dialdehyde, 6,6'-ditrifluoromethylbiphenyl-2,4'-dialdehyde, 6,6'-ditrifluoromethylbiphenyl-3,3'-dialdehyde, 6,6'-ditrifluoromethylbiphenyl-3,4'-dialdehyde, and 6,6'-ditrifluoromethylbiphenyl-4,4'-dialdehyde.

Specific examples of diphenyl ether dialdehydes include diphenyl ether-2,4'-dialdehyde, diphenyl ether-3,3'-dialdehyde, diphenyl ether-3,4'-dialdehyde, and diphenyl ether-4,4'-dialdehyde.

Specific examples of diphenylsulfone dialdehydes include diphenylsulfone-3,3'-dialdehyde, diphenylsulfone-3,4'-dialdehyde, and diphenylsulfone-4,4'-dialdehyde.

Specific examples of diphenyl sulfide dialdehydes include diphenyl sulfide-3,3'-dialdehyde, diphenyl sulfide-3,4'-dialdehyde, and diphenyl sulfide-4,4'-dialdehyde.

Specific examples of diphenyl ketone dialdehydes include diphenyl ketone-3,3'-dialdehyde, diphenyl ketone-3,4'-dialdehyde, and diphenyl ketone-4,4'-dialdehyde.

Specific examples of bis(formylphenoxy)benzenes include benzene 1,3-bis(3-formylphenoxy)benzene, 1,4-bis(3-formylphenoxy)benzene, and 1,4-bis(4-formylphenoxy)benzene.

Specific examples of [1,4-phenylenebis(1-methylethylidene)]bisbenzaldehydes include 3,3'-[1,4-phenylenebis(1-methylethylidene)]bisbenzaldehyde, 3,4'-[1,4-phenylenebis(1-methylethylidene)]bisbenzaldehyde, and 4,4'-[1,4-phenylenebis(1-methylethylidene)]bisbenzaldehyde.

Specific examples of 2,2-bis[4-(formylphenoxy)phenyl]propanes include 2,2-bis[4-(2-formylphenoxy)phenyl]propane, 2,2-bis[4-(3-formylphenoxy)phenyl]propane, 2,2-bis[4-(4-formylphenoxy)phenyl]propane, 2,2-bis[4-(3-formylphenoxy)phenyl]hexafluoropropane, and 2,2-bis[4-(4-formylphenoxy)phenyl]hexafluoropropane.

Specific examples of bis[4-(formylphenoxy)phenyl]sulfides include bis[4-(3-formylphenoxy)phenyl]sulfide and bis[4-(4-formylphenoxy)phenyl]sulfide.

Specific examples of bis[4-(formylphenoxy)phenyl]sulfones include bis[4-(3-formylphenoxy)phenyl]sulfone and bis[4-(4-formylphenoxy)phenyl]sulfone.

Specific examples of fluorene-containing aldehydes include fluorene-2,6-dialdehyde, fluorene-2,7-dialdehyde, dibenzofuran-3,7-dialdehyde, 9,9-bis(4-formylphenyl)fluorene, 9,9-bis(3-formylphenyl)fluorene, and 9-(3-formylphenyl)-9-(4'-formylphenyl)fluorene.

In addition, diphenylalkanedialdehyde or diphenylfluoroalkanedialdehyde represented by the following formula can also be suitably used as the aromatic dialdehyde compound.

Furthermore, a compound having an imide bond represented by the following formula can also be suitably used as the aromatic dialdehyde compound.

When the dicarbonyl compound represented by formula (a2-I) is an alicyclic dialdehyde containing an alicyclic group, preferred examples thereof include cyclohexane-1,4-dialdehyde, cyclohexane-1,3-dialdehyde, bicyclo[2.2.1]heptane-2,5-dialdehyde, bicyclo[2.2.2]octane-2,5-dialdehyde, bicyclo[2.2.2]oct-7-ene-2,5-dialdehyde, bicyclo[2.2.1]heptane-2,3-dialdehyde, bicyclo[2.2.1]hept-5-ene-2,3-dialdehyde, tricyclo[5.2.1.0 2,6]decane-3,4-dialdehyde, tricyclo[5.2.1.0 ^2,6 ]decane-3,4-dialdehyde, and tricyclo[5.2.1.0 ^2,6 ]decane-3,4-dialdehyde. ] dec-4-ene-8,9-dialdehyde, perhydronaphthalene-2,3-dialdehyde, perhydronaphthalene-1,4-dialdehyde, perhydronaphthalene-1,6-dialdehyde, perhydro-1,4-methanonaphthalene-2,3-dialdehyde, perhydro-1,4-methanonaphthalene-2,7-dialdehyde, perhydro-1,4-methanonaphthalene-7,8-dialdehyde, perhydro- 1,4:5,8-dimethanonaphthalene-2,3-dialdehyde, perhydro-1,4:5,8-dimethanonaphthalene-2,7-dialdehyde, perhydro-1,4:5,8:9,10-trimethanoanthracene-2,3-dialdehyde, bicyclohexyl-4,4'-dialdehyde, dicyclohexyl ether-3,4'-dialdehyde, dicyclohexylmethane-3,3'-dialdehyde, dicyclohexyl dicyclohexylmethane-3,4'-dialdehyde, dicyclohexylmethane-4,4'-dialdehyde, dicyclohexyldifluoromethane-3,3'-dialdehyde, dicyclohexyldifluoromethane-3,4'-dialdehyde, dicyclohexyldifluoromethane-4,4'-dialdehyde, dicyclohexylsulfone-3,3'-dialdehyde, dicyclohexylsulfone-3,4'-dialdehyde, dicyclo Hexyl sulfone-4,4'-dialdehyde, dicyclohexyl sulfide-3,3'-dialdehyde, dicyclohexyl sulfide-3,4'-dialdehyde, dicyclohexyl sulfide-4,4'-dialdehyde, dicyclohexyl ketone-3,3'-dialdehyde, dicyclohexyl ketone-3,4'-dialdehyde, dicyclohexyl ketone-4,4'-dialdehyde, 2,2-bis(3-formyl) 2,2-bis(4-formylcyclohexyl)propane, 2,2-bis(3-formylcyclohexyl)hexafluoropropane, 2,2-bis(4-formylcyclohexyl)hexafluoropropane, 1,3-bis(3-formylcyclohexyl)benzene, 1,4-bis(3-formylcyclohexyl)benzene, 1,4-bis(4-formylcyclohexyl)benzene cyclohexylene bis(1-methylethylidene)] biscyclohexanecarbaldehyde, 3,3'-[1,4-cyclohexylene bis(1-methylethylidene)] biscyclohexanecarbaldehyde, 3,4'-[1,4-cyclohexylene bis(1-methylethylidene)] biscyclohexanecarbaldehyde, 4,4'-[1,4-cyclohexylene bis(1-methylethylidene)] biscyclohexanecarbaldehyde, 2,2-bis[4-(3-formylcyclohexyl)cyclohexyl ]propane, 2,2-bis[4-(4-formylcyclohexyl)cyclohexyl]propane, 2,2-bis[4-(3-formylcyclohexyl)cyclohexyl]hexafluoropropane, 2,2-bis[4-(4-formylphenoxy)cyclohexyl]hexafluoropropane, bis[4-(3-formylcyclohexyloxy)cyclohexyl]sulfide, bis[4-(4-formylcyclohex bis[4-(3-formylcyclohexyloxy)cyclohexyl]sulfide, bis[4-(3-formylcyclohexyloxy)cyclohexyl]sulfone, bis[4-(4-formylcyclohexyloxy)cyclohexyl]sulfone, 2,2'-bicyclo[2.2.1]heptane-5,6'-dialdehyde, 2,2'-bicyclo[2.2.1]heptane-6,6'-dialdehyde, and 1,3-diformyladamantane.

Among the dialdehyde compounds described above, isophthalaldehyde is preferred because it is easy to synthesize and obtain, and because it is easy to obtain a polybenzoxazole precursor that gives a polybenzoxazole resin that has excellent heat resistance and mechanical properties.

（式（ａ２－ＩＩ）中、Ｒ^ａ０２３は、式（ａ０３）と同様であり、Ｈａｌはハロゲン原子である。） (Dicarboxylic acid dihalide)
The dicarboxylic acid dihalide used as a raw material of the polybenzoxazole precursor is a compound represented by the following formula (a2-II): The dicarboxylic acid dihalide may be used alone or in combination of two or more.

(In formula (a2-II), R ^a023 is the same as in formula (a03), and Hal is a halogen atom.)

In formula (a2-II), Hal is preferably chlorine, bromine, or iodine, and more preferably chlorine.

Preferable examples of the compound represented by formula (a2-II) include compounds in which the two aldehyde groups in the compounds described above as suitable examples of dialdehyde compounds are replaced with halocarbonyl groups, preferably chlorocarbonyl groups.

Among the dicarboxylic acid dihalides described above, terephthalic acid dichloride is preferred because it is easy to synthesize and obtain, and because it is easy to obtain a polybenzoxazole precursor that gives a polybenzoxazole resin that has excellent heat resistance and mechanical properties.

(solvent)
The solvent used in the preparation of the polyimide resin precursor or polybenzoxazole precursor is not particularly limited, and can be appropriately selected from solvents that have been used in the preparation of polyimide resin precursors or polybenzoxazole precursors in the past. As the solvent used in the preparation of the polyimide resin precursor or polybenzoxazole precursor, it is preferable to use a solvent containing a compound represented by the above formula (S01).

When a polybenzoxazole precursor is synthesized using a solvent containing the compound represented by the above formula (S01), even if the polybenzoxazole precursor is heat-treated at a low temperature, a polybenzoxazole resin having excellent mechanical properties such as tensile elongation and chemical resistance can be produced while suppressing the decrease in transparency caused by the coloring of the resin when the polybenzoxazole precursor is heated.

In addition, when a polybenzoxazole resin is produced by heating a polybenzoxazole precursor synthesized using a solvent containing the compound represented by the above formula (S01), the occurrence of defects such as blistering, cracking, and foaming on the surface of the polybenzoxazole resin can be suppressed. Therefore, when a film containing a polybenzoxazole precursor synthesized using a solvent containing the compound represented by formula (S01) is heated to produce a polybenzoxazole resin film, it is easy to produce a film with excellent appearance that is free of defects such as cracks, blisters, and pinholes.

Suitable examples of the compound represented by formula (S01) are as described above.

Among the compounds represented by formula (S01), N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea are particularly preferred. The boiling point of N,N,2-trimethylpropionamide at atmospheric pressure is 175°C, and the boiling point of N,N,N',N'-tetramethylurea at atmospheric pressure is 177°C. Thus, N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea have relatively low boiling points among solvents capable of dissolving aromatic diaminediols, dicarbonyl compounds, and the resulting polybenzoxazole precursors. For this reason, when a polybenzoxazole resin is formed using a polybenzoxazole precursor synthesized using a solvent containing at least one selected from N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea, the solvent is less likely to remain in the resulting polybenzoxazole resin when the polybenzoxazole precursor is heated, and the resulting polybenzoxazole resin is less likely to suffer from a decrease in tensile elongation.

Furthermore, N,N,2-trimethylpropionamide and N,N,N',N'-tetramethylurea are also useful in that they are low-hazard substances, as they are not designated as SVHCs (Substances of Very High Concern), substances of concern due to their harmful effects, under the REACH regulations of the EU (European Union).

When the solvent used to prepare the polybenzoxazole precursor contains a compound represented by formula (S01), the content of the compound represented by formula (S01) in the solvent is preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

When the solvent contains a compound represented by formula (S01), examples of organic solvents that can be used together with the compound represented by formula (S01) include nitrogen-containing polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, and 1,3-dimethyl-2-imidazolidinone; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; esters such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, ethyl lactate, methyl acetate, ethyl acetate, and n-butyl acetate; cyclic ethers such as dioxane and tetrahydrofuran; cyclic esters such as ethylene carbonate and propylene carbonate; aromatic hydrocarbons such as toluene and xylene; and sulfoxides such as dimethyl sulfoxide.

(Method for producing polybenzoxazole precursor)
The polybenzoxazole precursor is produced by reacting the above-mentioned aromatic diamine diol with a dicarbonyl compound in a solvent according to a known method. As representative examples of the method for producing the polybenzoxazole precursor, a method for producing the polybenzoxazole precursor when the dicarbonyl compound is a dialdehyde compound and a method for producing the polybenzoxazole precursor when the dicarbonyl compound is a dicarboxylic acid halide will be described below.

Reaction of aromatic diamine diol with dialdehyde compound The reaction of aromatic diamine diol with dialdehyde compound is a reaction for forming a Schiff base, and can be carried out according to a known method. The reaction temperature is not particularly limited, but is usually preferably 20°C or higher and 200°C or lower, more preferably 20°C or higher and 160°C or lower, and particularly preferably 100°C or higher and 160°C or lower.

The reaction between the aromatic diamine diol and the dialdehyde compound may be carried out by adding an entrainer to the solvent and dehydrating under reflux. The entrainer is not particularly limited and is appropriately selected from organic solvents that form an azeotropic mixture with water and form a two-phase system with water at room temperature. Suitable examples of the entrainer include esters such as isobutyl acetate, allyl acetate, n-propyl propionate, isopropyl propionate, n-butyl propionate, and isobutyl propionate; ethers such as dichloromethyl ether and ethyl isoamyl ether; ketones such as ethyl propyl ketone; and aromatic hydrocarbons such as toluene.

The reaction time between the aromatic diamine diol and the dialdehyde compound is not particularly limited, but is typically preferably from 2 hours to 72 hours.

When producing a polybenzoxazole precursor, the amount of the dialdehyde compound used is preferably 0.5 mol or more and 1.5 mol or less, and more preferably 0.7 mol or more and 1.3 mol or less, per 1 mol of the aromatic diamine diol.

The amount of the solvent used is not particularly limited as long as the reaction between the aromatic diamine diol and the dialdehyde compound proceeds smoothly. Typically, the solvent is used in an amount of 1 to 40 times, preferably 1.5 to 20 times, the total mass of the aromatic diamine diol and the dialdehyde compound.

The reaction between the aromatic diamine diol and the dialdehyde compound is carried out until the number average molecular weight of the resulting polybenzoxazole precursor is preferably 1,000 or more and 20,000 or less, more preferably 1,200 or more and 5,000 or less.

Reaction of aromatic diamine diol with dicarboxylic acid dihalide The reaction temperature for reacting aromatic diamine diol with dicarboxylic acid dihalide is not particularly limited, but is usually preferably from −20° C. to 150° C., more preferably from −10° C. to 150° C., and particularly preferably from −5° C. to 70° C. In the reaction of aromatic diamine diol with dicarboxylic acid dihalide, hydrogen halide is by-produced. In order to neutralize such hydrogen halide, a small amount of an organic base such as triethylamine, pyridine, or N,N-dimethyl-4-aminopyridine, or an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide may be added to the reaction solution.

The reaction time between the aromatic diamine diol and the dicarboxylic acid dihalide is not particularly limited, but is typically preferably from 2 hours to 72 hours.

When producing a polybenzoxazole precursor, the amount of dicarboxylic acid dihalide used is preferably 0.5 mol or more and 1.5 mol or less, and more preferably 0.7 mol or more and 1.3 mol or less, per 1 mol of aromatic diamine diol.

The amount of the solvent used is not particularly limited as long as the reaction between the aromatic diamine diol and the dicarboxylic acid dihalide proceeds smoothly. Typically, the solvent is used in an amount of 1 to 40 times, preferably 1.5 to 20 times, the total mass of the aromatic diamine diol and the dicarboxylic acid dihalide.

The reaction between the aromatic diamine diol and the dicarboxylic acid dihalide is carried out until the number average molecular weight of the resulting polybenzoxazole precursor is preferably 1,000 or more and 20,000 or less, more preferably 1,200 or more and 5,000 or less.

The method described above provides a solution of polybenzoxazole precursor. When preparing a metal oxide microparticle dispersion liquid containing a polybenzoxazole precursor as the base component (B), the solution of polybenzoxazole precursor may be used as is. In addition, a paste or solid of polybenzoxazole precursor obtained by removing at least a part of the solvent from the solution of polybenzoxazole precursor under reduced pressure at a low temperature at which the polybenzoxazole precursor is not converted to a polybenzoxazole resin can also be used to prepare the metal oxide microparticle dispersion liquid.

[Polybenzothiazole precursor]
Polybenzothiazole precursor is typically produced by reacting aromatic diamine dithiol with a dicarbonyl compound of a specific structure. As the aromatic diamine dithiol, a compound in which the hydroxyl group of the aromatic diamine diol used in the synthesis of polybenzoxazole precursor is replaced with a mercapto group can be used. As the dicarbonyl compound, the same one as that used in the synthesis of polybenzoxazole precursor can be used.

The reaction method, reaction conditions, etc., used when synthesizing a polybenzothiazole precursor by reacting an aromatic diaminediol with a dicarbonyl compound are the same as those used when synthesizing a polybenzoxazole precursor by reacting an aromatic diaminediol with a dicarbonyl compound.

[Polybenzimidazole precursor]
The polybenzimidazole precursor is typically produced by reacting an aromatic tetraamine with a dicarboxylic acid dihalide. As the aromatic tetraamine, a compound in which the hydroxyl group of the aromatic diamine diol used in the synthesis of the polybenzoxazole precursor is substituted with an amino group can be used. As the dicarboxylic acid dihalide, the same one as that used in the synthesis of the polybenzoxazole precursor can be used.

The reaction method and reaction conditions for synthesizing a polybenzimidazole precursor by reacting an aromatic tetraamine with a dicarboxylic acid dihalide are the same as those for synthesizing a polybenzoxazole precursor by reacting an aromatic diamine diol with a dicarboxylic acid dihalide.

[Styrene-maleic acid copolymer]
The type of styrene-maleic acid copolymer is not particularly limited as long as it does not impair the object of the present invention. The copolymerization ratio (mass ratio) of styrene/maleic acid in the styrene-maleic acid copolymer is preferably 1/9 or more and 9/1 or less, more preferably 2/8 or more and 8/1 or less, and particularly preferably 1/1 or more and 8/1 or less. The molecular weight of the styrene-maleic acid copolymer is not particularly limited, but is preferably 1000 or more and 100000 or less, and more preferably 5000 or more and 12000 or less, in terms of the mass average molecular weight in terms of polystyrene.

[Epoxy Group-Containing Resin]
When an epoxy group-containing resin is used as the base material component (B), the epoxy groups of the epoxy group-containing resin are crosslinked by heating the metal oxide fine particle dispersion liquid formed into a desired shape in the presence of a curing agent or curing accelerator as necessary. As a result, a cured product having excellent heat resistance and mechanical properties is obtained. The epoxy group-containing resin is not particularly limited as long as it is a resin composed of molecules having epoxy groups.

The epoxy group-containing resin may be a polymer obtained by polymerizing a monomer having an epoxy group or a monomer mixture containing a monomer having an epoxy group. The epoxy group-containing resin may be a polymer having a reactive functional group such as a hydroxyl group, a carboxyl group, or an amino group, to which an epoxy group has been introduced using a compound having an epoxy group such as epichlorohydrin. As a polymer having an epoxy group, a polymer obtained by polymerizing a monomer having an epoxy group or a monomer mixture containing a monomer having an epoxy group is preferred because it is easy to obtain, prepare, and adjust the amount of epoxy groups in the polymer.

Preferred examples of epoxy group-containing resins include novolac epoxy resins such as phenol novolac epoxy resins, brominated phenol novolac epoxy resins, orthocresol novolac epoxy resins, bisphenol A novolac epoxy resins, and bisphenol AD novolac epoxy resins; cyclic aliphatic epoxy resins such as epoxidized dicyclopentadiene phenol resins; and aromatic epoxy resins such as epoxidized naphthalene phenol resins.

Among epoxy group-containing resins, homopolymers of (meth)acrylic acid esters having epoxy groups or copolymers of (meth)acrylic acid esters having epoxy groups and other monomers are preferred because they are easy to prepare and the physical properties of the metal oxide-containing film can be easily adjusted.

The (meth)acrylic acid ester having an epoxy group may be a (meth)acrylic acid ester having a chain aliphatic epoxy group, or a (meth)acrylic acid ester having an alicyclic epoxy group as described later. The (meth)acrylic acid ester having an epoxy group may also contain an aromatic group. Among the (meth)acrylic acid esters having an epoxy group, aliphatic (meth)acrylic acid esters having a chain aliphatic epoxy group and aliphatic (meth)acrylic acid esters having an alicyclic epoxy group are preferred, aliphatic (meth)acrylic acid esters having an alicyclic epoxy group are more preferred, and from the viewpoint of patterning characteristics, aliphatic (meth)acrylic acid esters having an alicyclic epoxy group containing a polycyclic structure in the ring structure of the alicyclic epoxy group are even more preferred.

Examples of (meth)acrylic acid esters containing an aromatic group and having an epoxy group include 4-glycidyloxyphenyl (meth)acrylate, 3-glycidyloxyphenyl (meth)acrylate, 2-glycidyloxyphenyl (meth)acrylate, 4-glycidyloxyphenylmethyl (meth)acrylate, 3-glycidyloxyphenylmethyl (meth)acrylate, and 2-glycidyloxyphenylmethyl (meth)acrylate.

Examples of aliphatic (meth)acrylic acid esters having a linear aliphatic epoxy group include (meth)acrylic acid esters in which a linear aliphatic epoxy group is bonded to an oxy group (-O-) in an ester group (-O-CO-), such as epoxy alkyl (meth)acrylates and epoxy alkyl oxy alkyl (meth)acrylates. The linear aliphatic epoxy group in such (meth)acrylic acid esters may contain one or more oxy groups (-O-) in the chain. The number of carbon atoms in the linear aliphatic epoxy group is not particularly limited, but is preferably 3 to 20, more preferably 3 to 15, and particularly preferably 3 to 10.

Specific examples of aliphatic (meth)acrylic acid esters having linear aliphatic epoxy groups include epoxy alkyl (meth)acrylates such as glycidyl (meth)acrylate, 2-methyl glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 6,7-epoxyheptyl (meth)acrylate; and epoxy alkyl oxy alkyl (meth)acrylates such as 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxy-n-propyl (meth)acrylate, 4-glycidyloxy-n-butyl (meth)acrylate, 5-glycidyloxy-n-hexyl (meth)acrylate, and 6-glycidyloxy-n-hexyl (meth)acrylate.

Specific examples of aliphatic (meth)acrylic acid esters having an alicyclic epoxy group include compounds represented by the following formulae (a05-1) to (a05-15). Among these, compounds represented by the following formulae (a05-1) to (a05-5) are preferred, and compounds represented by the following formulae (a05-1) to (a05-2) are more preferred. In addition, for each of these compounds, the bonding site of the oxygen atom of the ester group to the alicyclic ring is not limited to the position shown here, and some positional isomers may be included.

In the above formula, R ^a032 represents a hydrogen atom or a methyl group, R ^a033 represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, R ^a034 represents a divalent hydrocarbon group having 1 to 10 carbon atoms, and t ⁰ represents an integer of 0 to 10. R ^a033 is preferably a linear or branched alkylene group, such as a methylene group, an ethylene group, a propylene group, a tetramethylene group, an ethylethylene group, a pentamethylene group, or a hexamethylene group. R ^a034 is preferably a methylene group, an ethylene group, a propylene group, a tetramethylene group, an ethylethylene group, a pentamethylene group, a hexamethylene group, a phenylene group, or a cyclohexylene group.

As the polymer having an epoxy group, either a homopolymer of a (meth)acrylic acid ester having an epoxy group or a copolymer of a (meth)acrylic acid ester having an epoxy group and another monomer can be used, but the content of units derived from a (meth)acrylic acid ester having an epoxy group in the polymer having an epoxy group is, for example, 1% by mass or more and 100% by mass or less, preferably 10% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 80% by mass or less, and particularly preferably 50% by mass or more and 75% by mass or less.

When the polymer having an epoxy group is a copolymer of a (meth)acrylic acid ester having an epoxy group and another monomer, the other monomer may be an unsaturated carboxylic acid, a (meth)acrylic acid ester not having an epoxy group, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, etc. These compounds may be used alone or in combination of two or more. From the viewpoint of the storage stability of the metal oxide fine particle dispersion and the chemical resistance of articles such as films formed using the metal oxide fine particle dispersion to alkalis, etc., it is preferable that the copolymer of a (meth)acrylic acid ester having an epoxy group and another monomer does not contain units derived from an unsaturated carboxylic acid.

Examples of unsaturated carboxylic acids include (meth)acrylic acid; (meth)acrylic acid amide; crotonic acid; maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and the anhydrides of these dicarboxylic acids.

Examples of (meth)acrylic acid esters that do not have an epoxy group include linear or branched alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, amyl (meth)acrylate, and tert-octyl (meth)acrylate; chloroethyl (meth)acrylate, 2,2-dimethylhydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, benzyl (meth)acrylate, and furfuryl (meth)acrylate; and (meth)acrylic acid esters that have a group with an alicyclic skeleton. Among (meth)acrylic acid esters that do not have an epoxy group, (meth)acrylic acid esters that have a group with an alicyclic skeleton are preferred.

In a (meth)acrylic acid ester having a group having an alicyclic skeleton, the alicyclic group constituting the alicyclic skeleton may be monocyclic or polycyclic. Examples of monocyclic alicyclic groups include a cyclopentyl group and a cyclohexyl group. Examples of polycyclic alicyclic groups include a norbornyl group, an isobornyl group, a tricyclononyl group, a tricyclodecyl group, and a tetracyclododecyl group.

Examples of (meth)acrylic acid esters having a group with an alicyclic skeleton include compounds represented by the following formulas (a06-1) to (a06-8). Among these, compounds represented by the following formulas (a06-3) to (a06-8) are preferred, and compounds represented by the following formulas (a06-3) or (a06-4) are more preferred.

In the above formula, R ^a035 represents a hydrogen atom or a methyl group, R ^a036 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms, and R ^a037 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ^a036 is preferably a single bond, a linear or branched alkylene group, such as a methylene group, an ethylene group, a propylene group, a tetramethylene group, an ethylethylene group, a pentamethylene group, or a hexamethylene group. R ^a037 is preferably a methyl group or an ethyl group.

Examples of (meth)acrylamides include (meth)acrylamide, N-alkyl(meth)acrylamide, N-aryl(meth)acrylamide, N,N-dialkyl(meth)acrylamide, N,N-aryl(meth)acrylamide, N-methyl-N-phenyl(meth)acrylamide, and N-hydroxyethyl-N-methyl(meth)acrylamide.

Examples of allyl compounds include allyl esters such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, and allyl lactate; allyloxyethanol; and the like.

Examples of vinyl ethers include aliphatic vinyl ethers such as hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, and tetrahydrofurfuryl vinyl ether; vinyl aryl ethers such as vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, and vinyl anthranyl ether; and the like.

Examples of vinyl esters include vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl barate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, vinyl butoxyacetate, vinyl phenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, and vinyl naphthoate.

Examples of styrenes include styrene; alkyl styrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, butylstyrene, hexylstyrene, cyclohexylstyrene, decylstyrene, benzylstyrene, chloromethylstyrene, trifluoromethylstyrene, ethoxymethylstyrene, and acetoxymethylstyrene; alkoxy styrenes such as methoxystyrene, 4-methoxy-3-methylstyrene, and dimethoxystyrene; and halostyrenes such as chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, and 4-fluoro-3-trifluoromethylstyrene.

The molecular weight of the epoxy group-containing resin is not particularly limited as long as it does not impair the object of the present invention, but the polystyrene-equivalent weight average molecular weight is preferably 3,000 to 30,000, and more preferably 5,000 to 15,000.

[Resins that form cured films upon baking]
As described above, the resin that forms a cured film by baking is also preferred as the precursor resin of the substrate component (B). Examples of the resin that forms a cured film by baking include silicon-containing resins. Preferred examples of silicon-containing resins include one or more selected from siloxane resins and polysilanes. A metal oxide-containing film containing a silicon-containing resin can be obtained by applying a metal oxide fine particle dispersion liquid containing these silicon-containing resins.
The metal oxide fine particle dispersion liquid, which is a silicon-containing resin composition, will be described in detail later.

When the above-mentioned thermosetting material or a resin that forms a cured film by baking is used as the base material component (B), the metal oxide microparticle dispersion may contain additives such as a curing agent, a curing accelerator, a dehydration condensation agent, an antioxidant, an ultraviolet absorber, a flame retardant, a release agent, a plasticizer, a filler, and a reinforcing material, as necessary.
In order to facilitate film formation, the metal oxide fine particle dispersion preferably contains a solvent, the type of which is appropriately selected depending on the type of thermosetting material.

As the metal oxide microparticle dispersion liquid, in addition to the non-energy-sensitive composition containing a non-thermosetting resin as the base component (B) and the heat-sensitive composition containing a thermosetting material as the base component (B) as described above, photosensitive compositions known as so-called photoresist compositions are also preferred.
The metal oxide microparticle dispersion liquid is preferably an energy-sensitive composition having heat sensitivity and/or photosensitivity, since it contains a well-dispersed metal oxide (A) and is easy to form articles such as films containing the metal oxide (A) having excellent heat resistance and chemical resistance.

A metal oxide fine particle dispersion liquid, which is an energy-sensitive composition, can be obtained by adding a desired amount of the above-mentioned metal oxide (A) to various conventionally known energy-sensitive compositions.
Conventionally known energy-sensitive compositions contain, as a base component (B), various thermosetting or photocurable compounds, alkali-soluble resins, resins whose solubility in alkali increases upon exposure to light, and the like.
The photosensitive metal oxide fine particle dispersion may be a negative photosensitive composition that becomes insoluble in a developer upon exposure to light, or a positive photosensitive composition that becomes soluble in a developer upon exposure to light.
A description will now be given of a suitable energy-sensitive composition and a silicon-containing resin composition, which is a suitable example of a composition containing a resin that forms a cured film upon baking.

(1) Energy-Sensitive Composition of First Aspect The energy-sensitive composition of the first aspect is a negative-type photosensitive composition containing an alkali-soluble resin, a photopolymerizable compound, and a photopolymerization initiator, as well as a metal oxide (A) and an organic solvent.
In the energy-sensitive composition of the first embodiment, the alkali-soluble resin and the photopolymerizable compound correspond to the base component (B).

The energy-sensitive composition of the first embodiment may contain, as an alkali-soluble resin, a (meth)acrylic resin obtained by polymerizing (meth)acrylic acid or a (meth)acrylic acid ester, as described below.
For example, when metal oxide fine particles that have been subjected to a coating treatment as described in Patent Document 1 are blended in a composition containing a (meth)acrylic resin, the metal oxide fine particles may not disperse well.
However, the above-mentioned surface-modified metal oxide fine particles, at least a portion of whose surface is coated with a carboxylic acid compound represented by formula (1) and/or a carboxylate derived from the carboxylic acid compound, are easily stably dispersed even in a composition containing a (meth)acrylic resin.

The alkali-soluble resin in the energy-sensitive composition of the first embodiment is not particularly limited, and any conventionally known alkali-soluble resin can be used. This alkali-soluble resin may or may not have an ethylenically unsaturated group.
In this specification, an alkali-soluble resin refers to a resin that dissolves to a thickness of 0.01 μm or more when a resin film having a thickness of 1 μm is formed on a substrate using a resin solution having a resin concentration of 20% by mass (solvent: propylene glycol monomethyl ether acetate) and then immersed in a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 1 minute.

As an alkali-soluble resin having an ethylenically unsaturated group, for example, a resin obtained by further reacting a reaction product of an epoxy compound with an unsaturated carboxylic acid with a polybasic acid anhydride can be used.

Among these, the resin represented by the following formula (a-1) is preferred. The resin represented by formula (a-1) is preferred because it has high photocurability.

In the above formula (a-1), ^Xa represents a group represented by the following formula (a-2).

In the above formula (a-2), R ^a1 each independently represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a halogen atom, R ^a2 each independently represents a hydrogen atom or a methyl group, and W ^a represents a single bond or a group represented by the following formula (a-3):

In the above formula (a-1), Y ^a represents a residue obtained by removing an acid anhydride group (—CO—O—CO—) from a dicarboxylic acid anhydride. Examples of dicarboxylic acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl-end-methylene-tetrahydrophthalic anhydride, chlorendic anhydride, methyltetrahydrophthalic anhydride, glutaric anhydride, etc.

In the above formula (a-1), Z ^a represents a residue obtained by removing two acid anhydride groups from a tetracarboxylic dianhydride. Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, and biphenyl ether tetracarboxylic dianhydride.
In the above formula (a-1), m represents an integer of 0 or more and 20 or less.

Examples of the alkali-soluble resin having an ethylenically unsaturated group include polyester (meth)acrylates obtained by reacting (meth)acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol with a monobasic acid or a polybasic acid; polyurethane (meth)acrylates obtained by reacting a polyol with a compound having two isocyanate groups and then reacting with (meth)acrylic acid; and epoxy (meth)acrylate resins obtained by reacting an epoxy resin such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol or cresol novolac type epoxy resin, a resol type epoxy resin, a triphenol methane type epoxy resin, a polycarboxylic acid polyglycidyl ester, a polyol polyglycidyl ester, an aliphatic or alicyclic epoxy resin, an amine epoxy resin, or a dihydroxybenzene type epoxy resin with (meth)acrylic acid.
As used herein, "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid. Similarly, "(meth)acrylate" refers to both acrylate and methacrylate.

On the other hand, as an alkali-soluble resin that does not have an ethylenically unsaturated group, a resin obtained by copolymerizing an unsaturated carboxylic acid with another unsaturated compound can be used. As the other unsaturated compound, it is preferable to use at least one selected from an epoxy group-containing unsaturated compound and an alicyclic group-containing unsaturated compound.

Examples of unsaturated carboxylic acids include monocarboxylic acids such as (meth)acrylic acid and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; and anhydrides of these dicarboxylic acids. Among these, (meth)acrylic acid and maleic anhydride are preferred in terms of copolymerization reactivity, alkali solubility of the resulting resin, and ease of availability. These unsaturated carboxylic acids can be used alone or in combination of two or more.

The epoxy group-containing unsaturated compound includes an epoxy group-containing unsaturated compound having no alicyclic group, and an epoxy group-containing unsaturated compound having an alicyclic group.
Examples of the epoxy group-containing unsaturated compound having an alicyclic group include the compounds represented by the above formulas (a05-1) to (a05-15).
Examples of epoxy group-containing unsaturated compounds having no alicyclic group include epoxyalkyl (meth)acrylates such as glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, and 6,7-epoxyheptyl (meth)acrylate; 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxy-n-propyl (meth)acrylate, 4-glycidyloxy-n-butyl (meth)acrylate, and 5-glycidyloxy-n-pentyl (meth)acrylate. and epoxyalkyloxyalkyl (meth)acrylates such as 6-glycidyloxy-n-hexyl (meth)acrylate; α-alkylacrylic acid epoxyalkyl esters such as α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate, α-n-butyl glycidyl acrylate, α-ethyl acrylate 6,7-epoxyheptyl; and glycidyl ethers such as o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether. Among these, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether are preferred from the standpoint of copolymerization reactivity, strength of the cured resin, and the like.
These epoxy group-containing unsaturated compounds may be used alone or in combination of two or more.

The alicyclic group-containing unsaturated compound is not particularly limited as long as it is an unsaturated compound having an alicyclic group. The alicyclic group may be monocyclic or polycyclic. Examples of monocyclic alicyclic groups include a cyclopentyl group and a cyclohexyl group. Examples of polycyclic alicyclic groups include an adamantyl group, a norbornyl group, an isobornyl group, a tricyclononyl group, a tricyclodecyl group, and a tetracyclododecyl group. Specific examples of the alicyclic group-containing unsaturated compound include the compounds represented by the above formulas (a06-1) to (a06-8).

It is also preferable to polymerize other compounds than those mentioned above with the unsaturated carboxylic acid. Examples of such other compounds include (meth)acrylic acid esters, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, maleimides, etc. These compounds can be used alone or in combination of two or more.

As for other compounds, suitable examples of (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, and styrenes are the same as the suitable examples of (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, and styrenes described for the copolymer of an epoxy group-containing (meth)acrylic acid ester and another monomer.

Other compounds such as (meth)acrylic acid esters include linear or branched alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, amyl (meth)acrylate, and tert-octyl (meth)acrylate; chloroethyl (meth)acrylate, 2,2-dimethylhydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, benzyl (meth)acrylate, and furfuryl (meth)acrylate; and the like.

Other maleimides include maleimides N-substituted with an alkyl group having 1 to 10 carbon atoms, such as N-methylmaleimide, N-ethylmaleimide, N-n-propylmaleimide, N-isopropylmaleimide, N-n-butylmaleimide, N-n-pentylmaleimide, and N-n-hexylmaleimide; maleimides N-substituted with an alicyclic group having 3 to 20 carbon atoms, such as N-cyclopentylmaleimide, N-cyclohexylmaleimide, and N-cycloheptylmaleimide; N-arylmaleimides N-substituted with an aryl group having 6 to 20 carbon atoms, such as N-phenylmaleimide, N-α-naphthylmaleimide, and N-β-naphthylmaleimide; and N-aralkylmaleimides N-substituted with an aralkyl group having 7 to 20 carbon atoms, such as N-benzylmaleimide and N-phenethylmaleimide.

In addition, a copolymer having at least a structural unit derived from an unsaturated carboxylic acid and a structural unit having a polymerizable site with a photopolymerizable compound described later, or a copolymer having at least a structural unit derived from an unsaturated carboxylic acid, a structural unit derived from an epoxy group-containing unsaturated compound, and a structural unit having a polymerizable site with a photopolymerizable compound described later can also be suitably used as the alkali-soluble resin.
When these alkali-soluble resins are used, a metal oxide-containing film that has excellent mechanical strength and adhesion to the substrate can be formed.

The copolymer having a structural unit having a polymerizable site with the above-mentioned photopolymerizable compound may further have one or more structural units derived from the above-mentioned (meth)acrylic acid esters, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, maleimides, etc.

The structural unit having a polymerizable site with a photopolymerizable compound preferably has an ethylenically unsaturated group as the polymerizable site with a photopolymerizable compound. A copolymer having such a structural unit can be prepared by reacting at least a part of the carboxyl group contained in the homopolymer of an unsaturated carboxylic acid with an epoxy group-containing unsaturated compound.
Furthermore, a copolymer having a structural unit having a polymerizable site with a photopolymerizable compound can also be prepared by reacting at least a portion of the epoxy groups in a copolymer having a structural unit derived from an unsaturated carboxylic acid and a structural unit derived from an epoxy group-containing unsaturated compound with an unsaturated carboxylic acid.

The proportion of the structural units derived from the unsaturated carboxylic acid in this alkali-soluble resin is preferably 3% by mass or more and 25% by mass or less, more preferably 5% by mass or more and 25% by mass or less. The proportion of the structural units derived from the epoxy group-containing unsaturated compound is preferably 30% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less. The proportion of the structural units derived from the alicyclic group-containing unsaturated compound is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less. By setting the proportion in the above range, the adhesiveness of the cured product of the energy-sensitive composition of the first embodiment to the substrate and the strength of the energy-sensitive composition of the first embodiment after curing can be increased while maintaining the alkali solubility of the resulting resin at a moderate level.

The weight average molecular weight of the alkali-soluble resin is preferably 1,000 to 40,000, and more preferably 2,000 to 30,000. By keeping it within the above range, it is possible to obtain sufficient heat resistance and film strength while obtaining good developability.

The content of the alkali-soluble resin is preferably 5% by mass or more and 80% by mass or less, and more preferably 15% by mass or more and 50% by mass or less, based on the solid content of the photosensitive composition of the first embodiment. By setting the content within the above range, it tends to be easier to balance the developability.

The photopolymerizable compound in the energy-sensitive composition of the first embodiment includes a monofunctional monomer and a polyfunctional monomer.
Examples of monofunctional monomers include (meth)acrylamide, methylol (meth)acrylamide, methoxymethyl (meth)acrylamide, ethoxymethyl (meth)acrylamide, propoxymethyl (meth)acrylamide, butoxymethoxymethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, crotonic acid, 2-acrylamido-2-methylpropanesulfonic acid, tert-butylacrylamidosulfonic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethyl (meth)acrylate, ethyl (meth)acrylate, butyl ... Examples of the monofunctional monomer include hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-(meth)acryloyloxy-2-hydroxypropyl phthalate, glycerin mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylamino (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, and half (meth)acrylate of a phthalic acid derivative. These monofunctional monomers can be used alone or in combination of two or more.

On the other hand, examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. , 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxypolyethoxyphenyl)propane, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid diglycidyl ester di(meth)acrylate, glycerin triacrylate, glycerin poly Examples of the polyfunctional monomers include polyglycidyl ether poly(meth)acrylate, urethane (meth)acrylate (i.e., tolylene diisocyanate), a reaction product of trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and 2-hydroxyethyl (meth)acrylate, methylene bis(meth)acrylamide, (meth)acrylamide methylene ether, and a condensation product of a polyhydric alcohol and N-methylol (meth)acrylamide, as well as triacrylformal. These polyfunctional monomers can be used alone or in combination of two or more.

The content of the photopolymerizable compound is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less, based on the solid content of the energy-sensitive composition of the first embodiment. By setting the content within the above range, it tends to be easier to balance the sensitivity, developability, and resolution.

The photopolymerization initiator in the energy-sensitive composition of the first embodiment is not particularly limited, and any conventionally known photopolymerization initiator can be used.

Specific examples of photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(4-dimethylaminophenyl)ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl], 1-(O-acetyloxime), (9-ethyl-6-nitro-9H-carbazol-3-yl)[4-(2-methoxy-1-methylethoxy)-2-methylphenyl]methanone O-acetyloxime, 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]-1-octanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-benzoyl-4'-methyl Dimethyl sulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 4-dimethylamino-2-ethylhexylbenzoic acid, 4-dimethylamino-2-isoamylbenzoic acid, benzyl-β-methoxyethyl acetal, benzyl dimethyl ketal, 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, methyl o-benzoylbenzoate, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 1-chloro-4-propoxythioxanthone, thio Xanthene, 2-chlorothioxanthene, 2,4-diethylthioxanthene, 2-methylthioxanthene, 2-isopropylthioxanthene, 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)-imidazolyl dimer, benzophenone, 2-chlorobenzophenone, p , p'-bisdimethylaminobenzophenone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, benzil, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone acetophenone, p-dimethylaminoacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, α,α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, pentyl-4-dimethylaminobenzoate, 9-phenylacridine, 1,7-bis-(9-acridinyl)heptane, 1,5-bis-(9-acridinyl)pentane, 1,3-bis-(9-acridinyl)propane, p-methoxytriazine, 2,4,6-tris(trichloromethyl)-s-triazine, 2 -methyl-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(furan-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-diethylamino-2-methylphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2 -(4-ethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-n-butoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine, etc. These photopolymerization initiators can be used alone or in combination of two or more.

Among these, the use of oxime ester-based photopolymerization initiators is particularly preferred in terms of sensitivity. Particularly preferred oxime-based photopolymerization initiators include O-acetyl-1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone oxime, ethanone, 1-[9-ethyl-6-(pyrrol-2-ylcarbonyl)-9H-carbazol-3-yl], 1-(O-acetyl oxime), and 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyl oxime)].

（Ｒ^ｃ１は、１価の有機基、アミノ基、ハロゲン、ニトロ基、及びシアノ基からなる群より選択される基であり、
ｎ１は０以上４以下の整数であり、
ｎ２は０、又は１であり、
Ｒ^ｃ２は、置換基を有してもよいフェニル基、又は置換基を有してもよいカルバゾリル基であり、
Ｒ^ｃ３は、水素原子、又は炭素原子数１以上６以下のアルキル基である。） As the photopolymerization initiator, it is also preferable to use an oxime ester compound represented by the following formula (c1).

(R ^c1 is a group selected from the group consisting of a monovalent organic group, an amino group, a halogen atom, a nitro group, and a cyano group;
n1 is an integer of 0 to 4,
n2 is 0 or 1;
R ^c2 is a phenyl group which may have a substituent, or a carbazolyl group which may have a substituent;
R ^c3 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In formula (c1), R ^c1 is not particularly limited as long as it does not impede the object of the present invention, and is appropriately selected from various organic groups. Suitable examples of R ^c1 when it is an organic group include an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, a saturated aliphatic acyl group, a saturated aliphatic acyloxy group, an alkoxycarbonyl group, a phenyl group which may have a substituent, a phenoxy group which may have a substituent, a benzoyl group which may have a substituent, a phenoxycarbonyl group which may have a substituent, a benzoyloxy group which may have a substituent, a phenylalkyl group which may have a substituent, a naphthyl group which may have a substituent, a naphthoxy group which may have a substituent, a naphthoyl group which may have a substituent, a naphthoxycarbonyl group which may have a substituent, a naphthyloxy group which may have a substituent, a naphthylalkyl group which may have a substituent, a heterocyclyl group which may have a substituent, an amino group, an amino group substituted with one or two organic groups, a morpholin-1-yl group, and a piperazin-1-yl group, a halogen, a nitro group, and a cyano group. When n1 is an integer of 2 or more and 4 or less, R ^c1 may be the same or different. In addition, the number of carbon atoms of a substituent does not include the number of carbon atoms of any further substituents that the substituent has.

When R ^c1 is an alkyl group, it preferably has 1 to 20 carbon atoms, and more preferably has 1 to 6 carbon atoms. When R ^c1 is an alkyl group, it may be a straight chain or a branched chain. Specific examples of when R ^c1 is an alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, an n-decyl group, and an isodecyl group. When R ^c1 is an alkyl group, the alkyl group may contain an ether bond (-O-) in the carbon chain. Examples of the alkyl group having an ether bond in the carbon chain include a methoxyethyl group, an ethoxyethyl group, a methoxyethoxyethyl group, an ethoxyethoxyethyl group, a propyloxyethoxyethyl group, and a methoxypropyl group.

When R ^c1 is an alkoxy group, the number of carbon atoms is preferably 1 to 20, and more preferably 1 to 6. When R ^c1 is an alkoxy group, it may be a straight chain or a branched chain. Specific examples of when R ^c1 is an alkoxy group include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an isooctyloxy group, a sec-octyloxy group, a tert-octyloxy group, an n-nonyloxy group, an isononyloxy group, an n-decyloxy group, and an isodecyloxy group. When R ^c1 is an alkoxy group, the alkoxy group may contain an ether bond (-O-) in the carbon chain. Examples of alkoxy groups having an ether bond in the carbon chain include a methoxyethoxy group, an ethoxyethoxy group, a methoxyethoxyethoxy group, an ethoxyethoxyethoxy group, a propyloxyethoxyethoxy group, and a methoxypropyloxy group.

When R ^c1 is a cycloalkyl group or a cycloalkoxy group, it preferably has 3 to 10 carbon atoms, and more preferably has 3 to 6 carbon atoms. Specific examples of when R ^c1 is a cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Specific examples of when R ^c1 is a cycloalkoxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, and a cyclooctyloxy group.

When R ^c1 is a saturated aliphatic acyl group or a saturated aliphatic acyloxy group, the carbon atom number is preferably from 2 to 20, and more preferably from 2 to 7. Specific examples of when R ^c1 is a saturated aliphatic acyl group include an acetyl group, a propanoyl group, a n-butanoyl group, a 2-methylpropanoyl group, a n-pentanoyl group, a 2,2-dimethylpropanoyl group, a n-hexanoyl group, a n-heptanoyl group, a n-octanoyl group, a n-nonanoyl group, a n-decanoyl group, a n-undecanoyl group, a n-dodecanoyl group, a n-tridecanoyl group, a n-tetradecanoyl group, a n-pentadecanoyl group, and a n-hexadecanoyl group. Specific examples of when R ^c1 is a saturated aliphatic acyloxy group include an acetyloxy group, a propanoyloxy group, a n-butanoyloxy group, a 2-methylpropanoyloxy group, a n-pentanoyloxy group, a 2,2-dimethylpropanoyloxy group, a n-hexanoyloxy group, a n-heptanoyloxy group, a n-octanoyloxy group, a n-nonanoyloxy group, a n-decanoyloxy group, a n-undecanoyloxy group, a n-dodecanoyloxy group, a n-tridecanoyloxy group, a n-tetradecanoyloxy group, a n-pentadecanoyloxy group, and a n-hexadecanoyloxy group.

When R ^c1 is an alkoxycarbonyl group, it preferably has 2 to 20 carbon atoms, and more preferably has 2 to 7 carbon atoms. Specific examples of when R ^c1 is an alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, an n-butyloxycarbonyl group, an isobutyloxycarbonyl group, a sec-butyloxycarbonyl group, a tert-butyloxycarbonyl group, an n-pentyloxycarbonyl group, an isopentyloxycarbonyl group, a sec-pentyloxycarbonyl group, a tert-pentyloxycarbonyl group, an n-hexyloxycarbonyl group, an n-heptyloxycarbonyl group, an n-octyloxycarbonyl group, an isooctyloxycarbonyl group, a sec-octyloxylcarbonyl group, a tert-octyloxycarbonyl group, an n-nonyloxycarbonyl group, an isononyloxycarbonyl group, an n-decyloxycarbonyl group, and an isodecyloxycarbonyl group.

When R ^c1 is a phenylalkyl group, it preferably has 7 to 20 carbon atoms, more preferably 7 to 10 carbon atoms. When R ^c1 is a naphthylalkyl group, it preferably has 11 to 20 carbon atoms, more preferably 11 to 14 carbon atoms. Specific examples of when R ^c1 is a phenylalkyl group include a benzyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a 4-phenylbutyl group. Specific examples of when R ^c1 is a naphthylalkyl group include an α-naphthylmethyl group, a β-naphthylmethyl group, a 2-(α-naphthyl)ethyl group, and a 2-(β-naphthyl)ethyl group. When R ^c1 is a phenylalkyl group or a naphthylalkyl group, R ^c1 may further have a substituent on the phenyl group or the naphthyl group.

When R ^c1 is a heterocyclyl group, the heterocyclyl group is a 5- or 6-membered monocyclic ring containing one or more N, S, or O, or a heterocyclyl group in which such monocyclic rings are fused together or such monocyclic ring is fused with a benzene ring. When the heterocyclyl group is a fused ring, the number of rings is up to 3. Examples of the heterocyclic ring constituting such a heterocyclyl group include furan, thiophene, pyrrole, oxazole, isoxazole, thiazole, thiadiazole, isothiazole, imidazole, pyrazole, triazole, pyridine, pyrazine, pyrimidine, pyridazine, benzofuran, benzothiophene, indole, isoindole, indolizine, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, quinoline, isoquinoline, quinazoline, phthalazine, cinnoline, and quinoxaline. When R ^c1 is a heterocyclyl group, the heterocyclyl group may further have a substituent.

When R ^c1 is an amino group substituted with one or two organic groups, suitable examples of the organic group include an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 10 carbon atoms, a saturated aliphatic acyl group having from 2 to 20 carbon atoms, a phenyl group which may have a substituent, a benzoyl group which may have a substituent, a phenylalkyl group having from 7 to 20 carbon atoms which may have a substituent, a naphthyl group which may have a substituent, a naphthyl group which may have a substituent, a naphthylalkyl group having from 11 to 20 carbon atoms which may have a substituent, and a heterocyclyl group, etc. Specific examples of these suitable organic groups are the same as those of R ^c1 . Specific examples of the amino group substituted with one or two organic groups include a methylamino group, an ethylamino group, a diethylamino group, an n-propylamino group, a di-n-propylamino group, an isopropylamino group, an n-butylamino group, a di-n-butylamino group, an n-pentylamino group, an n-hexylamino group, an n-heptylamino group, an n-octylamino group, an n-nonylamino group, an n-decylamino group, a phenylamino group, a naphthylamino group, an acetylamino group, a propanoylamino group, an n-butanoylamino group, an n-pentanoylamino group, an n-hexanoylamino group, an n-heptanoylamino group, an n-octanoylamino group, an n-decanoylamino group, a benzoylamino group, an α-naphthoylamino group, and a β-naphthoylamino group.

Examples of the substituent when the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c1 further have a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a saturated aliphatic acyl group having 2 to 7 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, a saturated aliphatic acyloxy group having 2 to 7 carbon atoms, a monoalkylamino group having an alkyl group having 1 to 6 carbon atoms, a dialkylamino group having an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, a halogen, a nitro group, and a cyano group. When the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c1 further have a substituent, the number of the substituent is not limited as long as it does not impede the object of the present invention, but is preferably 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c1 have multiple substituents, the multiple substituents may be the same or different.

Of R ^c1 , a group selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a saturated aliphatic acyl group having from 2 to 7 carbon atoms is preferred, from the viewpoints of chemical stability, less steric hindrance, ease of synthesis of the oxime ester compound, etc., an alkyl group having from 1 to 6 carbon atoms is more preferred, and a methyl group is particularly preferred.

The position at which R ^c1 bonds to the phenyl group is ^preferably the 4th or 5th position, and more preferably the 5th position, when the position of the bond between the phenyl group and the main skeleton of the oxime ester compound is the 1st position and the position of the methyl group is the 2nd position of the phenyl group to which R c1 is bonded. In addition, n1 is preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, and particularly preferably 0 or 1.

^Rc2 is a phenyl group which may have a substituent, or a carbazolyl group which may have a substituent. When ^Rc2 is a carbazolyl group which may have a substituent, the nitrogen atom on the carbazolyl group may be substituted with an alkyl group having 1 to 6 carbon atoms.

In R ^c2 , the substituents on the phenyl group or carbazolyl group are not particularly limited as long as they do not impair the object of the present invention. Examples of suitable substituents that the phenyl group or carbazolyl group may have on the carbon atom include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a saturated aliphatic acyl group having 2 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, a saturated aliphatic acyloxy group having 2 to 20 carbon atoms, a phenyl group which may have a substituent, a phenoxy group which may have a substituent, a phenylthio group which may have a substituent, a benzoyl group which may have a substituent, a phenoxycarbonyl group which may have a substituent, a substituent, Examples of such a group include a benzoyloxy group which may have a substituent, a phenylalkyl group having from 7 to 20 carbon atoms which may have a substituent, a naphthyl group which may have a substituent, a naphthoxy group which may have a substituent, a naphthoyl group which may have a substituent, a naphthoxycarbonyl group which may have a substituent, a naphthoyloxy group which may have a substituent, a naphthylalkyl group having from 11 to 20 carbon atoms which may have a substituent, a heterocyclyl group which may have a substituent, a heterocyclylcarbonyl group which may have a substituent, an amino group, an amino group substituted with one or two organic groups, a morpholin-1-yl group, a piperazin-1-yl group, a halogen, a nitro group, and a cyano group.

When R ^c2 is a carbazolyl group, examples of suitable substituents that the carbazolyl group may have on the nitrogen atom include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a saturated aliphatic acyl group having 2 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, a phenyl group that may have a substituent, a benzoyl group that may have a substituent, a phenoxycarbonyl group that may have a substituent, a phenylalkyl group having 7 to 20 carbon atoms that may have a substituent, a naphthyl group that may have a substituent, a naphthoyl group that may have a substituent, a naphthoxycarbonyl group that may have a substituent, a naphthylalkyl group having 11 to 20 carbon atoms that may have a substituent, a heterocyclyl group that may have a substituent, and a heterocyclylcarbonyl group that may have a substituent. Among these substituents, an alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 6 carbon atoms is more preferred, and an ethyl group is particularly preferred.

Specific examples of the substituent that the phenyl group or the carbazolyl group may have are the same as those of R c1 with respect to an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, a saturated aliphatic acyl group, an alkoxycarbonyl group, a saturated aliphatic acyloxy group, a phenylalkyl group which may have a substituent, a naphthylalkyl group which may have a substituent, a heterocyclyl group which may have a substituent, and ^an amino group substituted with one or two organic groups.

In R ^c2 , examples of the substituent when the phenyl group, or the phenyl group, naphthyl group, and heterocyclyl group contained in the substituent of the carbazolyl group further have a substituent include an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; a saturated aliphatic acyl group having 2 to 7 carbon atoms; an alkoxycarbonyl group having 2 to 7 carbon atoms; a saturated aliphatic acyloxy group having 2 to 7 carbon atoms; a phenyl group; a naphthyl group; a benzoyl group; a naphthoyl group; a benzoyl group substituted with a group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, and a phenyl group; a monoalkylamino group having an alkyl group having 1 to 6 carbon atoms; a dialkylamino group having an alkyl group having 1 to 6 carbon atoms; a morpholin-1-yl group; a piperazin-1-yl group; a halogen; a nitro group; and a cyano group. When the phenyl group, or the phenyl group, naphthyl group, and heterocyclyl group contained in the substituent of the carbazolyl group further have a substituent, the number of the substituents is not limited as long as it does not impair the object of the present invention, but is preferably from 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group have multiple substituents, the multiple substituents may be the same or different.

Among R ^c2 , from the viewpoint of easily obtaining a photopolymerization initiator excellent in sensitivity, a group represented by the following formula (c2) or (c3) is preferable, a group represented by the following formula (c2) is more preferable, and a group represented by the following formula (c2) in which A is S is particularly preferable.

（Ｒ^ｃ４は、１価の有機基、アミノ基、ハロゲン、ニトロ基、及びシアノ基からなる群より選択される基であり、ＡはＳ又はＯであり、ｎ３は、０以上４以下の整数である。）

(R ^c4 is a group selected from the group consisting of a monovalent organic group, an amino group, a halogen, a nitro group, and a cyano group, A is S or O, and n3 is an integer of 0 to 4.)

（Ｒ^ｃ５及びＲ^ｃ６は、それぞれ、１価の有機基である。）

(R ^c5 and R ^c6 are each a monovalent organic group.)

When R ^c4 in formula (c2) is an organic group, it can be selected from various organic groups as long as it does not impair the object of the present invention. Suitable examples of R ^c4 in formula (c2) when it is an organic group include an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; a saturated aliphatic acyl group having 2 to 7 carbon atoms; an alkoxycarbonyl group having 2 to 7 carbon atoms; a saturated aliphatic acyloxy group having 2 to 7 carbon atoms; a phenyl group; a naphthyl group; a benzoyl group; a naphthoyl group; a benzoyl group substituted with a group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, and a phenyl group; a monoalkylamino group having an alkyl group having 1 to 6 carbon atoms; a dialkylamino group having an alkyl group having 1 to 6 carbon atoms; a morpholin-1-yl group; a piperazin-1-yl group; a halogen; a nitro group; and a cyano group.

Among R ^c4 , a benzoyl group, a naphthoyl group, a benzoyl group substituted with a group selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, and a phenyl group, and a nitro group are preferred, and a benzoyl group, a naphthoyl group, a 2-methylphenylcarbonyl group, a 4-(piperazin-1-yl)phenylcarbonyl group, and a 4-(phenyl)phenylcarbonyl group are more preferred.

In addition, in formula (c2), n3 is preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, and particularly preferably 0 or 1. When n3 is 1, the position at which R ^c4 is bonded is preferably the para position with respect to the bond at which the phenyl group to which R ^c4 is bonded is bonded to an oxygen atom or a sulfur atom.

R ^c5 in formula (c3) can be selected from various organic groups within a range that does not impair the object of the present invention. Suitable examples of R ^c5 include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a saturated aliphatic acyl group having 2 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, a phenyl group which may have a substituent, a benzoyl group which may have a substituent, a phenoxycarbonyl group which may have a substituent, a phenylalkyl group having 7 to 20 carbon atoms which may have a substituent, a naphthyl group which may have a substituent, a naphthoyl group which may have a substituent, a naphthoxycarbonyl group which may have a substituent, a naphthylalkyl group having 11 to 20 carbon atoms which may have a substituent, a heterocyclyl group which may have a substituent, and a heterocyclylcarbonyl group which may have a substituent.

Among R ^c5 , an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, and an ethyl group is particularly preferable.

R ^c6 in formula (c3) is not particularly limited as long as it does not impair the object of the present invention, and can be selected from various organic groups. Specific examples of groups suitable for R ^c6 include an alkyl group having 1 to 20 carbon atoms, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, and a heterocyclyl group which may have a substituent. Of these groups, a phenyl group which may have a substituent is more preferable as R ^c6 , and a 2-methylphenyl group is particularly preferable.

Examples of the substituent when the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c4 , R ^c5 , or R ^c6 further have a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a saturated aliphatic acyl group having 2 to 7 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, a saturated aliphatic acyloxy group having 2 to 7 carbon atoms, a monoalkylamino group having an alkyl group having 1 to 6 carbon atoms, a dialkylamino group having an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, a halogen, a nitro group, and a cyano group. When the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c4 , R ^c5 , or R ^c6 further have a substituent, the number of the substituent is not limited as long as it does not impair the object of the present invention, but is preferably 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group included in R ^c4 , R ^c5 , or R ^c6 has multiple substituents, the multiple substituents may be the same or different.

In formula (c1), R ^c3 is a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms. R ^c3 is preferably a methyl group or an ethyl group, and more preferably a methyl group.

Among the oxime ester compounds represented by formula (c1), particularly suitable compounds include the following PI-1 to PI-42.

In addition, the oxime ester compound represented by the following formula (c4) is also preferred as a photopolymerization initiator.

（Ｒ^ｃ７は水素原子、ニトロ基又は１価の有機基であり、Ｒ^ｃ８及びＲ^ｃ９は、それぞれ、置換基を有してもよい鎖状アルキル基、置換基を有してもよい環状有機基、又は水素原子であり、Ｒ^ｃ８とＲ^ｃ９とは相互に結合して環を形成してもよく、Ｒ^ｃ１０は１価の有機基であり、Ｒ^ｃ１１は、水素原子、置換基を有してもよい炭素原子数１以上１１以下のアルキル基、又は置換基を有してもよいアリール基であり、ｎ４は０以上４以下の整数であり、ｎ５は０又は１である。）

(R ^c7 is a hydrogen atom, a nitro group or a monovalent organic group; R ^c8 and R ^c9 are each a chain alkyl group which may have a substituent, a cyclic organic group which may have a substituent, or a hydrogen atom; R ^c8 and R ^c9 may be bonded to each other to form a ring; R ^c10 is a monovalent organic group; R ^c11 is a hydrogen atom, an alkyl group having 1 to 11 carbon atoms which may have a substituent, or an aryl group which may have a substituent; n4 is an integer of 0 to 4, and n5 is 0 or 1.)

Here, the oxime compound for producing the oxime ester compound of formula (c4) is preferably a compound represented by the following formula (c5).

（Ｒ^ｃ７、Ｒ^ｃ８、Ｒ^ｃ９、Ｒ^ｃ１０、ｎ４、及びｎ５は、式（ｃ４）と同様である。）

(R ^c7 , R ^c8 , R ^c9 , R ^c10 , n4, and n5 are the same as in formula (c4).)

In formulas (c4) and (c5), R ^c7 is a hydrogen atom, a nitro group, or a monovalent organic group. R ^c7 is bonded to a 6-membered aromatic ring different from the 6-membered aromatic ring bonded to the group represented by -(CO) _n5 - on the fluorene ring in formula (c4). In formula (c4), the bonding position of R ^c7 to the fluorene ring is not particularly limited. When the compound represented by formula (c4) has one or more R ^c7 , it is preferable that one of the one or more R ^c7 is bonded to the 2-position in the fluorene ring, because the synthesis of the compound represented by formula (c4) is easy. When there are multiple R ^c7s , the multiple R ^c7s may be the same or different.

When R ^c7 is an organic group, R ^c7 is not particularly limited as long as it does not impede the object of the present invention, and is appropriately selected from various organic groups. When R ^c7 is an organic group, suitable examples include an alkyl group, an alkoxy group, a cycloalkyl group, a cycloalkoxy group, a saturated aliphatic acyl group, a saturated aliphatic acyloxy group, an alkoxycarbonyl group, a phenyl group which may have a substituent, a phenoxy group which may have a substituent, a benzoyl group which may have a substituent, a phenoxycarbonyl group which may have a substituent, a benzoyloxy group which may have a substituent, a phenylalkyl group which may have a substituent, a naphthyl group which may have a substituent, a naphthoxy group which may have a substituent, a naphthoyl group which may have a substituent, a naphthoxycarbonyl group which may have a substituent, a naphthyloxy group which may have a substituent, a naphthylalkyl group which may have a substituent, a heterocyclyl group which may have a substituent, a heterocyclylcarbonyl group which may have a substituent, an amino group substituted with one or two organic groups, a morpholin-1-yl group, and a piperazin-1-yl group.

When R ^c7 is an alkyl group, the number of carbon atoms of the alkyl group is preferably 1 or more and 20 or less, more preferably 1 or more and 6 or less. When R ^c7 is an alkyl group, it may be a straight chain or a branched chain. Specific examples of when R ^c7 is an alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, an n-decyl group, and an isodecyl group. When R ^c7 is an alkyl group, the alkyl group may contain an ether bond (-O-) in the carbon chain. Examples of the alkyl group having an ether bond in the carbon chain include a methoxyethyl group, an ethoxyethyl group, a methoxyethoxyethyl group, an ethoxyethoxyethyl group, a propyloxyethoxyethyl group, and a methoxypropyl group.

When R ^c7 is an alkoxy group, the number of carbon atoms of the alkoxy group is preferably 1 or more and 20 or less, more preferably 1 or more and 6 or less. When R ^c7 is an alkoxy group, it may be a straight chain or a branched chain. Specific examples of when R ^c7 is an alkoxy group include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an isooctyloxy group, a sec-octyloxy group, a tert-octyloxy group, an n-nonyloxy group, an isononyloxy group, an n-decyloxy group, and an isodecyloxy group. In addition, when R ^c7 is an alkoxy group, the alkoxy group may contain an ether bond (—O—) in the carbon chain. Examples of the alkoxy group having an ether bond in the carbon chain include a methoxyethoxy group, an ethoxyethoxy group, a methoxyethoxyethoxy group, an ethoxyethoxyethoxy group, a propyloxyethoxyethoxy group, and a methoxypropyloxy group.

When R ^c7 is a cycloalkyl group or a cycloalkoxy group, the number of carbon atoms of the cycloalkyl group or the cycloalkoxy group is preferably 3 to 10, more preferably 3 to 6. Specific examples of when R ^c7 is a cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Specific examples of when R ^c7 is a cycloalkoxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, and a cyclooctyloxy group.

When R ^c7 is a saturated aliphatic acyl group or a saturated aliphatic acyloxy group, the number of carbon atoms in the saturated aliphatic acyl group or the saturated aliphatic acyloxy group is preferably 2 to 21, and more preferably 2 to 7. Specific examples of when R ^c7 is a saturated aliphatic acyl group include an acetyl group, a propanoyl group, a n-butanoyl group, a 2-methylpropanoyl group, a n-pentanoyl group, a 2,2-dimethylpropanoyl group, a n-hexanoyl group, a n-heptanoyl group, a n-octanoyl group, a n-nonanoyl group, a n-decanoyl group, a n-undecanoyl group, a n-dodecanoyl group, a n-tridecanoyl group, a n-tetradecanoyl group, a n-pentadecanoyl group, and a n-hexadecanoyl group. Specific examples of when R ^c7 is a saturated aliphatic acyloxy group include an acetyloxy group, a propanoyloxy group, a n-butanoyloxy group, a 2-methylpropanoyloxy group, a n-pentanoyloxy group, a 2,2-dimethylpropanoyloxy group, a n-hexanoyloxy group, a n-heptanoyloxy group, a n-octanoyloxy group, a n-nonanoyloxy group, a n-decanoyloxy group, a n-undecanoyloxy group, a n-dodecanoyloxy group, a n-tridecanoyloxy group, a n-tetradecanoyloxy group, a n-pentadecanoyloxy group, and a n-hexadecanoyloxy group.

When R ^c7 is an alkoxycarbonyl group, the alkoxycarbonyl group preferably has 2 or more and 20 or less, and more preferably has 2 or more and 7 or less carbon atoms. Specific examples of when R ^c7 is an alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, an n-butyloxycarbonyl group, an isobutyloxycarbonyl group, a sec-butyloxycarbonyl group, a tert-butyloxycarbonyl group, an n-pentyloxycarbonyl group, an isopentyloxycarbonyl group, a sec-pentyloxycarbonyl group, a tert-pentyloxycarbonyl group, an n-hexyloxycarbonyl group, an n-heptyloxycarbonyl group, an n-octyloxycarbonyl group, an isooctyloxycarbonyl group, a sec-octyloxycarbonyl group, a tert-octyloxycarbonyl group, an n-nonyloxycarbonyl group, an isononyloxycarbonyl group, an n-decyloxycarbonyl group, and an isodecyloxycarbonyl group.

When R ^c7 is a phenylalkyl group, the number of carbon atoms of the phenylalkyl group is preferably 7 to 20, more preferably 7 to 10. When R ^c7 is a naphthylalkyl group, the number of carbon atoms of the naphthylalkyl group is preferably 11 to 20, more preferably 11 to 14. Specific examples of when R ^c7 is a phenylalkyl group include a benzyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a 4-phenylbutyl group. Specific examples of when R ^c7 is a naphthylalkyl group include an α-naphthylmethyl group, a β-naphthylmethyl group, a 2-(α-naphthyl)ethyl group, and a 2-(β-naphthyl)ethyl group. When R ^c7 is a phenylalkyl group or a naphthylalkyl group, R ^c7 may further have a substituent on the phenyl group or the naphthyl group.

When R ^c7 is a heterocyclyl group, the heterocyclyl group is a 5- or 6-membered monocyclic ring containing one or more N, S, or O, or a heterocyclyl group in which such monocyclic rings are fused to each other, or such monocyclic ring is fused to a benzene ring. When the heterocyclyl group is a fused ring, the number of rings is up to 3. The heterocyclyl group may be an aromatic group (heteroaryl group) or a non-aromatic group. Examples of the heterocyclic ring constituting such a heterocyclyl group include furan, thiophene, pyrrole, oxazole, isoxazole, thiazole, thiadiazole, isothiazole, imidazole, pyrazole, triazole, pyridine, pyrazine, pyrimidine, pyridazine, benzofuran, benzothiophene, indole, isoindole, indolizine, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, quinoline, isoquinoline, quinazoline, phthalazine, cinnoline, quinoxaline, piperidine, piperazine, morpholine, piperidine, tetrahydropyran, and tetrahydrofuran. When R ^c7 is a heterocyclyl group, the heterocyclyl group may further have a substituent.

When R ^c7 is a heterocyclylcarbonyl group, the heterocyclyl group contained in the heterocyclylcarbonyl group is the same as when R ^c7 is a heterocyclyl group.

When R ^c7 is an amino group substituted with one or two organic groups, suitable examples of the organic group include an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 10 carbon atoms, a saturated aliphatic acyl group having from 2 to 21 carbon atoms, a phenyl group which may have a substituent, a benzoyl group which may have a substituent, a phenylalkyl group having from 7 to 20 carbon atoms which may have a substituent, a naphthyl group which may have a substituent, a naphthyl group which may have a substituent, a naphthylalkyl group having from 11 to 20 carbon atoms which may have a substituent, and a heterocyclyl group. Specific examples of these suitable organic groups are the same as those of R ^c7 . Specific examples of the amino group substituted with one or two organic groups include a methylamino group, an ethylamino group, a diethylamino group, an n-propylamino group, a di-n-propylamino group, an isopropylamino group, an n-butylamino group, a di-n-butylamino group, an n-pentylamino group, an n-hexylamino group, an n-heptylamino group, an n-octylamino group, an n-nonylamino group, an n-decylamino group, a phenylamino group, a naphthylamino group, an acetylamino group, a propanoylamino group, an n-butanoylamino group, an n-pentanoylamino group, an n-hexanoylamino group, an n-heptanoylamino group, an n-octanoylamino group, an n-decanoylamino group, a benzoylamino group, an α-naphthoylamino group, and a β-naphthoylamino group.

Examples of the substituent when the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c7 further have a substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a saturated aliphatic acyl group having 2 to 7 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, a saturated aliphatic acyloxy group having 2 to 7 carbon atoms, a monoalkylamino group having an alkyl group having 1 to 6 carbon atoms, a dialkylamino group having an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazin-1-yl group, a halogen, a nitro group, and a cyano group. When the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c7 further have a substituent, the number of the substituent is not limited as long as it does not impair the object of the present invention, but is preferably 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group contained in R ^c7 have multiple substituents, the multiple substituents may be the same or different.

Among the groups described above, R ^c7 is preferably a nitro group or a group represented by R ^c12 -CO-, since this tends to improve sensitivity. R ^c12 is not particularly limited as long as it does not impair the object of the present invention, and can be selected from various organic groups. Examples of groups suitable for R ^c12 include an alkyl group having 1 to 20 carbon atoms, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, and a heterocyclyl group which may have a substituent. Among these groups, a 2-methylphenyl group, a thiophen-2-yl group, and an α-naphthyl group are particularly preferred for R ^c12 .
In addition, when R ^c7 is a hydrogen atom, the transparency tends to be good, which is preferable. Note that when R ^c7 is a hydrogen atom and R ^c10 is a group represented by the formula (c4a) or (c4b) described later, the transparency tends to be even better.

In formula (c4), R ^c8 and R ^c9 are each a chain alkyl group which may have a substituent, a cyclic organic group which may have a substituent, or a hydrogen atom. R ^c8 and R ^c9 may be bonded to each other to form a ring. Among these groups, R ^c8 and R ^c9 are preferably a chain alkyl group which may have a substituent. When R ^c8 and R ^c9 are a chain alkyl group which may have a substituent, the chain alkyl group may be a linear alkyl group or a branched alkyl group.

When R ^c8 and R ^c9 are chain alkyl groups having no substituents, the number of carbon atoms of the chain alkyl group is preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, and particularly preferably 1 or more and 6 or less. Specific examples of the chain alkyl group when R ^c8 and R ^c9 are chain alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, isooctyl group, sec-octyl group, tert-octyl group, n-nonyl group, isononyl group, n-decyl group, and isodecyl group. In addition, when R ^c8 and R ^c9 are alkyl groups, the alkyl group may contain an ether bond (-O-) in the carbon chain. Examples of the alkyl group having an ether bond in the carbon chain include a methoxyethyl group, an ethoxyethyl group, a methoxyethoxyethyl group, an ethoxyethoxyethyl group, a propyloxyethoxyethyl group, and a methoxypropyl group.

When R ^c8 and R ^c9 are chain alkyl groups having a substituent, the number of carbon atoms in the chain alkyl group is preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, and particularly preferably 1 or more and 6 or less. In this case, the number of carbon atoms in the substituent is not included in the number of carbon atoms in the chain alkyl group. The chain alkyl group having a substituent is preferably linear.
The substituent that the alkyl group may have is not particularly limited as long as it does not impair the object of the present invention. Suitable examples of the substituent include a cyano group, a halogen atom, a cyclic organic group, and an alkoxycarbonyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom, a chlorine atom, and a bromine atom are preferred. Examples of the cyclic organic group include a cycloalkyl group, an aromatic hydrocarbon group, and a heterocyclyl group. Specific examples of the cycloalkyl group are the same as the suitable examples when R ^c7 is a cycloalkyl group. Specific examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a phenanthryl group. Specific examples of the heterocyclyl group are the same as the suitable examples when R ^c7 is a heterocyclyl group. When R ^c7 is an alkoxycarbonyl group, the alkoxy group contained in the alkoxycarbonyl group may be linear or branched, and is preferably linear. The alkoxy group contained in the alkoxycarbonyl group preferably has 1 or more and 10 or less, and more preferably has 1 or more and 6 or less, carbon atoms.

When the chain alkyl group has a substituent, the number of the substituents is not particularly limited. The preferred number of the substituents varies depending on the number of carbon atoms in the chain alkyl group. The number of the substituents is typically 1 to 20, preferably 1 to 10, and more preferably 1 to 6.

When R ^c8 and R ^c9 are cyclic organic groups, the cyclic organic group may be an alicyclic group or an aromatic group. Examples of the cyclic organic group include an aliphatic cyclic hydrocarbon group, an aromatic hydrocarbon group, and a heterocyclyl group. When R ^c8 and R ^c9 are cyclic organic groups, the substituents that the cyclic organic group may have are the same as those when R ^c8 and R ^c9 are chain alkyl groups.

When R ^c8 and R ^c9 are aromatic hydrocarbon groups, the aromatic hydrocarbon group is preferably a phenyl group, a group formed by bonding multiple benzene rings via carbon-carbon bonds, or a group formed by condensing multiple benzene rings. When the aromatic hydrocarbon group is a phenyl group or a group formed by bonding or condensing multiple benzene rings, the number of benzene rings contained in the aromatic hydrocarbon group is not particularly limited, and is preferably 3 or less, more preferably 2 or less, and particularly preferably 1. Specific preferred examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a phenanthryl group.

When R ^c8 and R ^c9 are an aliphatic cyclic hydrocarbon group, the aliphatic cyclic hydrocarbon group may be monocyclic or polycyclic. The number of carbon atoms of the aliphatic cyclic hydrocarbon group is not particularly limited, but is preferably 3 to 20, more preferably 3 to 10. Examples of monocyclic cyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, isobornyl, tricyclononyl, tricyclodecyl, tetracyclododecyl, and adamantyl groups.

When R ^c8 and R ^c9 are heterocyclyl groups, the heterocyclyl group is a 5- or 6-membered monocyclic ring containing one or more N, S, or O, or a heterocyclyl group in which such monocyclic rings are fused to each other or such monocyclic ring is fused to a benzene ring. When the heterocyclyl group is a fused ring, the number of rings is up to 3. The heterocyclyl group may be an aromatic group (heteroaryl group) or a non-aromatic group. Examples of heterocycles constituting such heterocyclyl groups include furan, thiophene, pyrrole, oxazole, isoxazole, thiazole, thiadiazole, isothiazole, imidazole, pyrazole, triazole, pyridine, pyrazine, pyrimidine, pyridazine, benzofuran, benzothiophene, indole, isoindole, indolizine, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, quinoline, isoquinoline, quinazoline, phthalazine, cinnoline, quinoxaline, piperidine, piperazine, morpholine, piperidine, tetrahydropyran, and tetrahydrofuran.

R ^c8 and R ^c9 may be bonded to each other to form a ring. The group consisting of the ring formed by R ^c8 and R ^c9 is preferably a cycloalkylidene group. When R ^c8 and R ^c9 are bonded to form a cycloalkylidene group, the ring constituting the cycloalkylidene group is preferably a 5-membered to 6-membered ring, and more preferably a 5-membered ring.

When the group formed by combining ^Rc8 and ^Rc9 is a cycloalkylidene group, the cycloalkylidene group may be fused with one or more other rings. Examples of the ring that may be fused with the cycloalkylidene group include a benzene ring, a naphthalene ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a furan ring, a thiophene ring, a pyrrole ring, a pyridine ring, a pyrazine ring, and a pyrimidine ring.

Among the above-described R ^c8 and R ^c9 , a suitable example of the group is a group represented by the formula -A ¹ -A ^2. In the formula, A ¹ is a linear alkylene group, and A ² is an alkoxy group, a cyano group, a halogen atom, a halogenated alkyl group, a cyclic organic group, or an alkoxycarbonyl group.

The number of carbon atoms of the linear alkylene group of A ¹ is preferably 1 to 10, more preferably 1 to 6. When A ² is an alkoxy group, the alkoxy group may be linear or branched, and linear is preferred. The number of carbon atoms of the alkoxy group is preferably 1 to 10, and more preferably 1 to 6. When A ² is a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is preferred, and a fluorine atom, a chlorine atom, or a bromine atom is more preferred. When A ² is a halogenated alkyl group, the halogen atom contained in the halogenated alkyl group is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and a fluorine atom, a chlorine atom, or a bromine atom is more preferred. The halogenated alkyl group may be linear or branched, and linear is preferred. When A ² is a cyclic organic group, examples of the cyclic organic group are the same as the cyclic organic groups that R ^c8 and R ^c9 have as substituents. When ^A2 is an alkoxycarbonyl group, examples of the alkoxycarbonyl group are the same as the alkoxycarbonyl groups which ^Rc8 and ^Rc9 have as substituents.

Preferable specific examples of R ^c8 and R ^c9 include alkyl groups such as an ethyl group, an n-propyl group, an n-butyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group; alkoxyalkyl groups such as a 2-methoxyethyl group, a 3-methoxy-n-propyl group, a 4-methoxy-n-butyl group, a 5-methoxy-n-pentyl group, a 6-methoxy-n-hexyl group, a 7-methoxy-n-heptyl group, an 8-methoxy-n-octyl group, a 2-ethoxyethyl group, a 3-ethoxy-n-propyl group, a 4-ethoxy-n-butyl group, a 5-ethoxy-n-pentyl group, a 6-ethoxy-n-hexyl group, a 7-ethoxy-n-heptyl group, and an 8-ethoxy-n-octyl group; cyanoalkyl groups such as 2-phenylethyl group, 3-phenyl-n-propyl group, 4-phenyl-n-butyl group, 5-phenyl-n-pentyl group, 6-phenyl-n-hexyl group, 7-phenyl-n-heptyl group, and 8-phenyl-n-octyl group; phenylalkyl groups such as 2-cyclohexylethyl group, 3-cyclohexyl-n-propyl group, 4-cyclohexyl-n-butyl group, 5-cyclohexyl-n-pentyl group, 6-cyclohexyl-n-hexyl group, 7-cyclohexyl-n-heptyl group, and 8-cyclohexyl-n-octyl group; 2-cyclohexylethyl group, 3-cyclohexyl-n-propyl group, 4-cyclohexyl-n-butyl group, 5-cyclohexyl-n-pentyl group, 6-cyclohexyl-n-hexyl group, 7-cyclohexyl-n-heptyl group, 8-cyclohexyl-n-octyl group, 2-cyclopentylethyl group, 3-cyclopentyl-n-propyl group, cycloalkylalkyl groups such as 4-cyclopentyl-n-butyl group, 5-cyclopentyl-n-pentyl group, 6-cyclopentyl-n-hexyl group, 7-cyclopentyl-n-heptyl group, and 8-cyclopentyl-n-octyl group; 2-methoxycarbonylethyl group, 3-methoxycarbonyl-n-propyl group, 4-methoxycarbonyl-n-butyl group, 5-methoxycarbonyl-n-pentyl group, 6-methoxycarbonyl-n-hexyl group, 7-methoxycarbonyl-n-heptyl group, 8-methoxycarbonyl-n-octyl group, 2-ethoxycarbonylethyl group, 3-ethoxycarbonyl-n-propyl group, 4-ethoxycarbonyl-n-butyl group, 5-ethoxycarbonyl-n-pentyl group, 6-ethoxycarbonyl-n-hexyl group, 7-methoxycarbonyl-n-heptyl group, 8-methoxycarbonyl-n-octyl group, 2-ethoxycarbonylethyl group, 3-ethoxycarbonyl-n-propyl group, 4-ethoxycarbonyl-n-butyl group, 5-ethoxycarbonyl-n-pentyl group, 6-ethoxycarbonyl alkoxycarbonylalkyl groups such as 2-chloroethyl group, 3-chloro-n-propyl group, 4-chloro-n-butyl group, 5-chloro-n-pentyl group, 6-chloro-n-hexyl group, 7-chloro-n-heptyl group, and 8-ethoxycarbonyl-n-octyl group; and halogenated alkyl groups such as 2-chloroethyl group, 3-chloro-n-propyl group, 4-chloro-n-butyl group, 5-chloro-n-pentyl group, 6-chloro-n-hexyl group, 7-chloro-n-heptyl group, 8-chloro-n-octyl group, 2-bromoethyl group, 3-bromo-n-propyl group, 4-bromo-n-butyl group, 5-bromo-n-pentyl group, 6-bromo-n-hexyl group, 7-bromo-n-heptyl group, 8-bromo-n-octyl group, 3,3,3-trifluoropropyl group, and 3,3,4,4,5,5,5-heptafluoro-n-pentyl group.

Among the above, preferred groups for R ^c8 and R ^c9 are an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, a 2-methoxyethyl group, a 2-cyanoethyl group, a 2-phenylethyl group, a 2-cyclohexylethyl group, a 2-methoxycarbonylethyl group, a 2-chloroethyl group, a 2-bromoethyl group, a 3,3,3-trifluoropropyl group, and a 3,3,4,4,5,5,5-heptafluoro-n-pentyl group.

As with R ^c7 , examples of suitable organic groups for R ^c10 include alkyl groups, alkoxy groups, cycloalkyl groups, cycloalkoxy groups, saturated aliphatic acyl groups, alkoxycarbonyl groups, saturated aliphatic acyloxy groups, phenyl groups which may have a substituent, phenoxy groups which may have a substituent, benzoyl groups which may have a substituent, phenoxycarbonyl groups which may have a substituent, benzoyloxy groups which may have a substituent, phenylalkyl groups which may have a substituent, naphthyl groups which may have a substituent, naphthoxy groups which may have a substituent, naphthoyl groups which may have a substituent, naphthoxycarbonyl groups which may have a substituent, naphthoyloxy groups which may have a substituent, naphthylalkyl groups which may have a substituent, heterocyclyl groups which may have a substituent, heterocyclylcarbonyl groups which may have a substituent, amino groups substituted with one or two organic groups, morpholin-1-yl groups, and piperazin-1-yl groups. Specific examples of these groups are the same as those described for R ^c7 . Also preferred as R ^c10 are a cycloalkylalkyl group, a phenoxyalkyl group which may have a substituent on the aromatic ring, and a phenylthioalkyl group which may have a substituent on the aromatic ring. The substituents which the phenoxyalkyl group and the phenylthioalkyl group may have are the same as the substituents which the phenyl group included in R ^c7 may have.

Among the organic groups, R ^c10 is preferably an alkyl group, a cycloalkyl group, a phenyl group which may have a substituent, or a cycloalkylalkyl group, or a phenylthioalkyl group which may have a substituent on the aromatic ring. As the alkyl group, an alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 8 carbon atoms is more preferred, an alkyl group having 1 to 4 carbon atoms is particularly preferred, and a methyl group is most preferred. Among the phenyl groups which may have a substituent, a methylphenyl group is preferred, and a 2-methylphenyl group is more preferred. The number of carbon atoms of the cycloalkylalkyl group contained in the cycloalkylalkyl group is preferably 5 to 10, more preferably 5 to 8, and particularly preferably 5 or 6. The number of carbon atoms of the alkylene group contained in the cycloalkylalkyl group is preferably 1 to 8, more preferably 1 to 4, and particularly preferably 2. Among the cycloalkylalkyl groups, a cyclopentylethyl group is preferred. The number of carbon atoms of the alkylene group contained in the phenylthioalkyl group which may have a substituent on the aromatic ring is preferably 1 to 8, more preferably 1 to 4, and particularly preferably 2. Among the phenylthioalkyl groups which may have a substituent on the aromatic ring, a 2-(4-chlorophenylthio)ethyl group is preferred.

Also preferred as R ^c10 is a group represented by -A ³ -CO-O-A ^4. A ³ is a divalent organic group, preferably a divalent hydrocarbon group, and preferably an alkylene group. ^{A 4} is a monovalent organic group, preferably a monovalent hydrocarbon group.

When ^A3 is an alkylene group, the alkylene group may be linear or branched, and is preferably linear. When ^A3 is an alkylene group, the number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6, and particularly preferably 1 to 4.

Suitable examples of ^A4 include an alkyl group having from 1 to 10 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, and an aromatic hydrocarbon group having from 6 to 20 carbon atoms. Suitable specific examples of ^A4 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, a phenyl group, a naphthyl group, a benzyl group, a phenethyl group, an α-naphthylmethyl group, and a β-naphthylmethyl group.

Specific preferred examples of the group represented by -A ³ -CO-O-A ⁴ include a 2-methoxycarbonylethyl group, a 2-ethoxycarbonylethyl group, a 2-n-propyloxycarbonylethyl group, a 2-n-butyloxycarbonylethyl group, a 2-n-pentyloxycarbonylethyl group, a 2-n-hexyloxycarbonylethyl group, a 2-benzyloxycarbonylethyl group, a 2-phenoxycarbonylethyl group, a 3-methoxycarbonyl-n-propyl group, a 3-ethoxycarbonyl-n-propyl group, a 3-n-propyloxycarbonyl-n-propyl group, a 3-n-butyloxycarbonyl-n-propyl group, a 3-n-pentyloxycarbonyl-n-propyl group, a 3-n-hexyloxycarbonyl-n-propyl group, a 3-benzyloxycarbonyl-n-propyl group, and a 3-phenoxycarbonyl-n-propyl group.

（式（ｃ４ａ）及び（ｃ４ｂ）中、Ｒ^ｃ１３及びＲ^ｃ１４はそれぞれ有機基であり、ｎ６は０以上４以下の整数であり、Ｒ^ｃ１３及びＲ^ｃ１４がベンゼン環上の隣接する位置に存在する場合、Ｒ^ｃ１３とＲ^ｃ１４とが互いに結合して環を形成してもよく、ｎ７は１以下８以下の整数であり、ｎ８は１以上５以下の整数であり、ｎ９は０以上（ｎ８＋３）以下の整数であり、Ｒ^ｃ１５は有機基である。） R ^c10 has been described above. As R ^c10 , a group represented by the following formula (c4a) or (c4b) is preferable.

(In formulae (c4a) and (c4b), R ^c13 and R ^c14 each represent an organic group; n6 represents an integer of 0 to 4; when R ^c13 and R ^c14 are present at adjacent positions on the benzene ring, R ^c13 and R ^c14 may be bonded to each other to form a ring; n7 represents an integer of 1 to 8; n8 represents an integer of 1 to 5; n9 represents an integer of 0 to (n8+3); and R ^c15 represents an organic group.)

Examples of organic groups for R ^c13 and R ^c14 in formula (c4a) are the same as those for R ^c7 . R ^c13 is preferably an alkyl group or a phenyl group. When R ^c13 is an alkyl group, the number of carbon atoms is preferably 1 or less and 10 or more, more preferably 1 or more and 5 or less, particularly preferably 1 or more and 3 or less, and most preferably 1. That is, R ^c13 is most preferably a methyl group. When R ^c13 and R ^c14 are bonded to form a ring, the ring may be an aromatic ring or an aliphatic ring. Suitable examples of the group represented by formula (c4a) in which R ^c13 and R ^c14 form a ring include a naphthalene-1-yl group and a 1,2,3,4-tetrahydronaphthalene-5-yl group. In the above formula (c4a), n6 is an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

In the above formula (c4b), R ^c15 is an organic group. Examples of the organic group include the same groups as those described for R ^c7 . Among the organic groups, an alkyl group is preferable. The alkyl group may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3. Preferred examples of R ^c15 include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group, and among these, a methyl group is more preferable.

In the above formula (c4b), n8 is an integer of 1 or more and 5 or less, preferably an integer of 1 or more and 3 or less, and more preferably 1 or 2. In the above formula (c4b), n9 is an integer of 0 or more and (n8+3) or less, preferably an integer of 0 or more and 3 or less, more preferably an integer of 0 or more and 2 or less, and particularly preferably 0. In the above formula (c4b), n7 is an integer of 1 or more and 8 or less, preferably an integer of 1 or more and 5 or less, more preferably an integer of 1 or more and 3 or less, and particularly preferably 1 or 2.

In formula (c4), R ^c11 is a hydrogen atom, an alkyl group having 1 to 11 carbon atoms which may have a substituent, or an aryl group which may have a substituent. When R ^c11 is an alkyl group, preferred examples of the substituent that may be present include a phenyl group and a naphthyl group. When R ^c7 is an aryl group, preferred examples of the substituent that may be present include an alkyl group having 1 to 5 carbon atoms, an alkoxy group, and a halogen atom.

In formula (c4), preferred examples of R ^c11 include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a phenyl group, a benzyl group, a methylphenyl group, and a naphthyl group. Among these, a methyl group or a phenyl group is more preferred.

The compound represented by formula (c4) is produced by a method including a step of converting an oxime group (>C=N-OH) contained in the compound represented by formula (c5) described above into an oxime ester group represented by >C=N-O-COR ^c11 . R ^c11 is the same as R ^c11 in formula (c4).

The conversion of an oxime group (>C=N-OH) to an oxime ester group represented by >C=N-O-COR ^c11 is carried out by reacting the compound represented by the above formula (c5) with an acylating agent.
Examples of acylating agents that give an acyl group represented by ^{--COR.sup.c11} include acid anhydrides represented by ( ^R.sup.c11CO ) _.sub.2O and acid halides represented by ^{R.sup.c11COHal} (Hal is a halogen atom).

Preferable specific examples of the compound represented by formula (c4) include the following PI-43 to PI-83.

The content of the photopolymerization initiator is preferably 0.5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the solid content of the energy-sensitive composition of the first embodiment. By setting the content within the above range, sufficient heat resistance and chemical resistance can be obtained, and the coating film forming ability can be improved and curing defects can be suppressed.

As described above, the energy-sensitive composition of the first embodiment as a metal oxide microparticle dispersion contains a metal oxide (A). Therefore, a pattern containing a metal oxide (A) can be formed using the energy-sensitive composition of the first embodiment.

The energy sensitive composition of the first embodiment may further contain a colorant.
The colorant is not particularly limited, but for example, it is preferable to use a compound classified as a pigment in the Color Index (C.I.; published by The Society of Dyers and Colourists), specifically, a pigment assigned a Color Index (C.I.) number such as those listed below.

C.I. Pigment Yellow 1 (hereinafter, the same applies to "C.I. Pigment Yellow", and only the numbers are listed), 3, 11, 12, 13, 14, 15, 16, 17, 20, 24, 31, 53, 55, 60, 61, 65, 71, 73, 74, 81, 83, 86, 93, 95, 97, 98, 99, 100, 101, 104,106,108,109,110,113,114,116,117,119,120,125,126,127,128,129,137,138,139,147,148,150,151,152,153,154,155,156,166,167,1 68, 175, 180, 185;
C.I. Pigment Orange 1 (hereinafter, the same applies to "C.I. Pigment Orange", and only the numbers are listed), 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 55, 59, 61, 63, 64, 71, 73;
C.I. Pigment Violet 1 (hereinafter, the same applies to "C.I. Pigment Violet", and only the numbers are listed), 19, 23, 29, 30, 32, 36, 37, 38, 39, 40, 50;
C.I. Pigment Red 1 (hereinafter, "C.I. Pigment Red" is the same, and only the numbers are described.), 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 53:1, 57, 57:1, 57:2, 58:2, 58:4, 60:1, 63:1, 63:2, 64:1, 81:1, 83, 88, 90:1, 97, 1 01, 102, 104, 105, 106, 108, 112, 113, 114, 122, 123, 144, 146, 149, 150, 151, 155, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 180, 185, 18 7, 188, 190, 192, 193, 194, 202, 206, 207, 208, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 242, 243, 245, 254, 255, 264, 265;
C.I. Pigment Blue 1 (hereinafter, the same applies to "C.I. Pigment Blue", and only the numbers are listed), 2, 15, 15:3, 15:4, 15:6, 16, 22, 60, 64, 66;
C.I. Pigment Green 7, C.I. Pigment Green 36, C.I. Pigment Green 37;
C.I. Pigment Brown 23, C.I. Pigment Brown 25, C.I. Pigment Brown 26, C.I. Pigment Brown 28;
C.I. Pigment Black 1, C.I. Pigment Black 7.

When the colorant is a light-shielding agent, it is preferable to use a black pigment as the light-shielding agent. Examples of black pigments include carbon black, titanium black, metal oxides such as copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, and silver, composite oxides, metal sulfides, metal sulfates, and metal carbonates, regardless of whether they are organic or inorganic. Of these, it is preferable to use carbon black, which has high light-shielding properties.

As the carbon black, known carbon blacks such as channel black, furnace black, thermal black, and lamp black can be used, but it is preferable to use channel black, which has excellent light-shielding properties. Resin-coated carbon black may also be used. Resin-coated carbon black has lower conductivity than carbon black without a resin coating.

In addition, the above organic pigments may be added as auxiliary pigments to adjust the color tone of the carbon black.

A dispersant may be further used to disperse the colorant uniformly in the photosensitive composition. As such a dispersant, it is preferable to use a polyethyleneimine-based, urethane resin-based, or acrylic resin-based polymer dispersant. In particular, when carbon black is used as the colorant, it is preferable to use an acrylic resin-based dispersant as the dispersant.

In addition, the inorganic pigment and the organic pigment may be used alone or in combination. When used in combination, it is preferable to use the organic pigment in a range of 10 parts by mass to 80 parts by mass, and more preferably in a range of 20 parts by mass to 40 parts by mass, per 100 parts by mass of the total amount of the inorganic pigment and the organic pigment.

The content of the colorant may be appropriately determined depending on the application of the energy-sensitive composition of the first embodiment, but as an example, it is preferably 5 parts by mass or more and 70 parts by mass or less, and more preferably 25 parts by mass or more and 60 parts by mass or less, per 100 parts by mass of the solid content of the energy-sensitive composition of the first embodiment.

It is preferable to disperse the colorant at an appropriate concentration using a dispersant to prepare a dispersion, and then add the dispersion to the photosensitive composition.

Examples of the organic solvent in the energy-sensitive composition of the first embodiment include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, and propylene glycol mono. (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate. (Poly)alkylene glycol monoalkyl ether acetates such as diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, tetrahydrofuran and other ethers; ketones such as methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone; alkyl esters of lactate such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate; ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, ethyl 2-hydroxy- Examples of the organic solvent include 3-methylbutane methyl, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl formate, isopentyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, and ethyl 2-oxobutanoate; aromatic hydrocarbons such as toluene and xylene; and amides such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and the solvent represented by the above formula (S01). These organic solvents can be used alone or in combination of two or more.

Among the above organic solvents, amides such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, cyclohexanone, 3-methoxybutyl acetate, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and the solvent represented by the above formula (S01) are preferred because they exhibit excellent solubility for the above alkali-soluble resin, the above photopolymerizable compound, and the above photopolymerization initiator.

The content of the organic solvent is preferably such that the solids concentration of the energy-sensitive composition of the first embodiment is 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less.

(2) Energy-sensitive composition of the second embodiment The energy-sensitive composition of the second embodiment is a positive-type photosensitive composition. When the energy-sensitive composition of the second embodiment is a chemically amplified positive-type photosensitive composition, the chemically amplified positive-type photosensitive composition contains a metal oxide (A), an acid generator (hereinafter also referred to as a photoacid generator) that generates an acid upon irradiation with actinic rays or radiation, and a resin (hereinafter also referred to as a photosensitive resin) that is a base component (B) and whose solubility in alkali increases due to the action of the acid. The positive-type photosensitive resin composition may contain components such as an alkali-soluble resin, an acid diffusion inhibitor, and an organic solvent, as necessary. Other examples of the energy-sensitive composition of the second embodiment include a positive-type photosensitive composition containing a quinone diazide group-containing compound and an alkali-soluble resin having a phenolic hydroxyl group, such as a novolak phenolic resin (e.g., a novolak resin (C1) described below, a polyhydroxystyrene resin (C2), or an acrylic resin (C3) having a phenolic hydroxyl group).

The film thickness of the resist pattern formed using the energy-sensitive composition of the second embodiment is not particularly limited. The energy-sensitive composition of the second embodiment is preferably used to form a thick resist pattern. The film thickness of the resist pattern formed using the energy-sensitive composition of the second embodiment is not particularly limited, and specifically, it is preferably 0.1 μm or more, more preferably 1 μm or more and 150 μm or less, particularly preferably 10 μm or more and 120 μm or less, and most preferably 20 μm or more and 80 μm or less.

Below, we will explain the essential and optional components contained in the energy-sensitive composition of the second embodiment and the method for producing the photosensitive resin composition.

The photoacid generator is a compound that generates an acid when irradiated with actinic rays or radiation, and is not particularly limited as long as it is a compound that generates an acid directly or indirectly when exposed to light.
Hereinafter, preferred examples of the photoacid generator that can be preferably used in the energy-sensitive composition of the second embodiment will be described.

A first example of a suitable photoacid generator is a compound represented by the following formula (a1):

In the above formula (a1), X ^1a represents a sulfur atom or iodine atom having an atomic valence of g, and g is 1 or 2. h represents the number of repeating units of the structure in parentheses. R ^1a is an organic group bonded to X ^1a , and represents an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms, and R ^1a may be substituted with at least one selected from the group consisting of alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, alkylthio, aryl, heterocyclic, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkyleneoxy, amino, cyano, and nitro groups, and halogen. The number of R ^1a is g+h(g-1)+1, and R ^1a may be the same as or different from each other. Two or more R ^1a may be bonded to each other directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -NR ^2a -, -CO-, -COO-, -CONH-, an alkylene group having 1 to 3 carbon atoms, or a phenylene group to form a ring structure containing X ^1a . R ^2a is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms.

^X2a is a structure represented by the following formula (a2).

In the above formula (a2), X ^{4a represents an alkylene group having 1 to 8 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a divalent group of a heterocyclic compound having 8 to 20 carbon atoms, and X 4a may} be substituted with at least one selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, a hydroxyl group, a cyano group, a nitro group, and a halogen group. X ^5a represents -O-, -S-, -SO-, -SO ₂ -, -NH-, -NR ^2a -, -CO-, -COO-, -CONH-, an alkylene group having 1 to 3 carbon atoms, or a phenylene group. h represents the number of repeating units of the structure in parentheses. h+1 X ^4a and h X ^5a may be the same or different. R ^2a is the same as defined above.

X ^3a- is a counter ion of the onium, and examples of such an anion include a fluorinated alkylfluorophosphate anion represented by the following formula (a17) and a borate anion represented by the following formula (a18).

In the above formula (a17), ^R3a represents an alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms. j represents the number of R3a and is an integer of 1 to 5. The j ^R3a may be the same or different.

In the above formula (a18), R ^4a to R ^7a each independently represent a fluorine atom or a phenyl group, and some or all of the hydrogen atoms of the phenyl group may be substituted with at least one selected from the group consisting of fluorine atoms and trifluoromethyl groups.

The onium ions in the compound represented by the above formula (a1) include triphenylsulfonium, tri-p-tolylsulfonium, 4-(phenylthio)phenyldiphenylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-{bis[4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis( 4-fluorophenyl)sulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(diphenyl)sulfonio]thioxanthone, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium sulfonium, diphenylphenacylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, phenyl[4-(4-biphenylthio)phenyl]4-biphenylsulfonium, phenyl[4-(4-biphenylthio)phenyl]3-biphenylsulfonium, [4-(4-acetophenylthio)phenyl]diphenylsulfonium, octadecylmethylphenacylsulfonium, diphenyliodonium, di-p-tolyliodonium, bis(4-dodecylphenyl)iodonium, bis(4-methoxyphenyl)iodonium, (4-octyloxyphenyl)phenyliodonium, bis(4-decyloxy)phenyliodonium, 4-(2-hydroxytetradecyloxy)phenylphenyliodonium, 4-isopropylphenyl(p-tolyl)iodonium, or 4-isobutylphenyl(p-tolyl)iodonium, etc.

Among the onium ions in the compound represented by formula (a1) above, a preferred onium ion is the sulfonium ion represented by formula (a19) below.

In the above formula (a19), R ^8a each independently represents a group selected from the group consisting of a hydrogen atom, an alkyl, a hydroxyl, an alkoxy, an alkylcarbonyl, an alkylcarbonyloxy, an alkyloxycarbonyl, a halogen atom, an aryl which may have a substituent, and an arylcarbonyl. ^{X 2a} has the same meaning as X ^2a in the above formula (a1).

Specific examples of the sulfonium ion represented by the above formula (a19) include 4-(phenylthio)phenyldiphenylsulfonium, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, phenyl[4-(4-biphenylthio)phenyl]4-biphenylsulfonium, phenyl[4-(4-biphenylthio)phenyl]3-biphenylsulfonium, [4-(4-acetophenylthio)phenyl]diphenylsulfonium, and diphenyl[4-(p-terphenylthio)phenyl]diphenylsulfonium.

In the fluorinated alkyl fluorophosphate anion represented by the above formula (a17), R ^3a represents an alkyl group substituted with a fluorine atom, and the number of carbon atoms is preferably 1 to 8, more preferably 1 to 4. Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and octyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, and tert-butyl; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The ratio of hydrogen atoms in the alkyl group substituted with fluorine atoms is usually 80% or more, preferably 90% or more, and more preferably 100%. When the substitution rate of fluorine atoms is less than 80%, the acid strength of the onium fluorinated alkyl fluorophosphate represented by the above formula (a1) decreases.

Particularly preferred R ^3a is a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms and a fluorine atom substitution rate of 100%, specific examples of which include CF ₃ , CF ₃ CF ₂ , (CF ₃ ) ₂ CF, CF ₃ CF ₂ CF ₂ , CF ₃ CF ₂ CF ₂ CF ₂ , (CF ₃ ) ₂ CFCF ₂ , CF ₃ CF ₂ (CF ₃ ) CF, and (CF ₃ ) ₃ C. The number j of ^{R 3a} is an integer of 1 to 5, preferably 2 to 4, and particularly preferably 2 or 3.

Specific examples of preferred fluorinated alkyl fluorophosphate anions include, [(CF ₃ CF ₂ ) ₂ PF ₄ ] ⁻ , [(CF ₃ CF ₂ ) ₃ PF ₃ ] ⁻ , [((CF ₃ ) ₂ CF) ₂ PF ₄ ] ⁻ , [((CF ₃ ) ₂ CF) ₃ PF ₃ ] ⁻ , [(CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ] ⁻ , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ⁻ , [((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ] ⁻ , [((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ] ⁻ , [( _CF CF ₂ CF ₂ CF ₂ ) ₂ PF ₄ ] ^- , or [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- , of which, [(CF ₃ CF ₂ ) ₃ PF ₃ ] ^- , [(CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ CF) ₃ PF ₃ ] ^- , [((CF ₃ ) ₂ CF) ₂ PF ₄ ] ^- , [((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ] ^- , or [((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ] ^- are particularly preferred.

Preferred specific examples of the borate anion represented by the above formula (a18) include tetrakis(pentafluorophenyl)borate ([B(C ₆ F ₅ ) ₄ ] ⁻ ), tetrakis[(trifluoromethyl)phenyl]borate ([B(C ₆ H ₄ CF ₃ ) ₄ ] ⁻ ), difluorobis(pentafluorophenyl)borate ([(C ₆ F ₅ ) ₂ BF ₂ ] ⁻ ), trifluoro(pentafluorophenyl)borate ([(C ₆ F ₅ )BF ₃ ] ⁻ ), tetrakis(difluorophenyl)borate ([B(C ₆ H ₃ F ₂ ) ₄ ] ⁻ ), and the like. Of these, tetrakis(pentafluorophenyl)borate ([B(C ₆ F ₅ ) ₄ ] ⁻ ) is particularly preferred.

A second example of a suitable photoacid generator is 2,4-bis(trichloromethyl)-6-piperonyl-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(2-furyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methyl-2-furyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-ethyl-2-furyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-propyl-2-furyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,5-dimethoxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3 ,5-diethoxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,5-dipropoxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3-methoxy-5-ethoxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3-methoxy-5-propoxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,4-methylenedioxyphenyl)ethenyl]-s-triazine, 2,4-bis(trichloromethyl)-6-(3,4-methylenedioxyphenyl)-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy) Phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-[2-(2-furyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-[2-(5-methyl-2-furyl)ethenyl]-4,6-bis( trichloromethyl)-1,3,5-triazine, 2-[2-(3,5-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine, 2-(3,4-methylenedioxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, tris(1,3-dibromopropyl)-1,3,5-triazine, tris(2,3-dibromopropyl)-1,3,5-triazine, and halogen-containing triazine compounds represented by the following formula (a3), such as tris(2,3-dibromopropyl)isocyanurate, are included.

In the above formula (a3), R ^9a , R ^10a and R ^11a each independently represent a halogenated alkyl group.

A third example of a suitable photoacid generator includes α-(p-toluenesulfonyloxyimino)-phenylacetonitrile, α-(benzenesulfonyloxyimino)-2,4-dichlorophenylacetonitrile, α-(benzenesulfonyloxyimino)-2,6-dichlorophenylacetonitrile, α-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, and a compound represented by the following formula (a4) containing an oxime sulfonate group.

In the above formula (a4), R ^12a represents a monovalent, divalent, or trivalent organic group, R ^13a represents a substituted or unsubstituted saturated hydrocarbon group, unsaturated hydrocarbon group, or aromatic compound group, and n represents the number of repeating units of the structure in parentheses.

In the above formula (a4), the aromatic compound group refers to a group of a compound that exhibits physical and chemical properties specific to aromatic compounds, and examples thereof include aryl groups such as phenyl and naphthyl groups, and heteroaryl groups such as furyl and thienyl groups. These may have one or more suitable substituents on the ring, such as halogen atoms, alkyl groups, alkoxy groups, and nitro groups. R ^13a is particularly preferably an alkyl group having 1 to 6 carbon atoms, and examples of such groups include methyl, ethyl, propyl, and butyl groups. In particular, compounds in which R ^12a is an aromatic compound group and R ^13a is an alkyl group having 1 to 4 carbon atoms are preferred.

Examples of the photoacid generator represented by the above formula (a4) include, when n=1, compounds in which R ^12a is any one of a phenyl group, a methylphenyl group, and a methoxyphenyl group, and R ^13a is a methyl group, specifically α-(methylsulfonyloxyimino)-1-phenylacetonitrile, α-(methylsulfonyloxyimino)-1-(p-methylphenyl)acetonitrile, α-(methylsulfonyloxyimino)-1-(p-methoxyphenyl)acetonitrile, [2-(propylsulfonyloxyimino)-2,3-dihydroxythiophen-3-ylidene](o-tolyl)acetonitrile, etc. When n=2, examples of the photoacid generator represented by the above formula (a4) include photoacid generators represented by the following formula:

A fourth example of a suitable photoacid generator is an onium salt having a naphthalene ring in the cation portion. "Having a naphthalene ring" means having a structure derived from naphthalene, and means that at least two ring structures and their aromaticity are maintained. The naphthalene ring may have a substituent such as a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxyl group, or a linear or branched alkoxy group having 1 to 6 carbon atoms. The structure derived from the naphthalene ring may be a monovalent group (one free valence) or a divalent group (two or more free valences), but is preferably a monovalent group (however, in this case, the free valence is counted excluding the portion bonded to the above-mentioned substituent). The number of naphthalene rings is preferably 1 to 3.

The cation moiety of such an onium salt having a naphthalene ring in the cation moiety is preferably a structure represented by the following formula (a5).

In the above formula (a5), at least one of R ^14a , R ^15a , and R ^16a represents a group represented by the following formula (a6), and the remaining represent a linear or branched alkyl group having from 1 to 6 carbon atoms, a phenyl group which may have a substituent, a hydroxyl group, or a linear or branched alkoxy group having from 1 to 6 carbon atoms. Alternatively, one of R ^14a , R ^15a , and R ^16a is a group represented by the following formula (a6), and the remaining two are each independently a linear or branched alkylene group having from 1 to 6 carbon atoms, the ends of which may be bonded to form a ring.

In the above formula (a6), R ^17a and R ^18a each independently represent a hydroxyl group, a linear or branched alkoxy group having 1 to 6 carbon atoms, or a linear or branched alkyl group having 1 to 6 carbon atoms, and R ^19a represents a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms which may have a substituent. l and m each independently represent an integer of 0 to 2, and l + m is 3 or less. However, when there are multiple R ^17a , they may be the same or different from each other. Also, when there are multiple R ^18a , they may be the same or different from each other.

Of the above R ^14a , R ^15a , and R ^16a , the number of groups represented by the above formula (a6) is preferably one in terms of the stability of the compound, and the remainder are linear or branched alkylene groups having 1 to 6 carbon atoms, the ends of which may be bonded to form a ring. In this case, the two alkylene groups form a 3- to 9-membered ring including the sulfur atom. The number of atoms (including the sulfur atom) constituting the ring is preferably 5 to 6.

In addition, examples of the substituents that the alkylene group may have include an oxygen atom (which forms a carbonyl group together with the carbon atom that constitutes the alkylene group), a hydroxyl group, etc.

In addition, examples of the substituents that the phenyl group may have include a hydroxyl group, a linear or branched alkoxy group having 1 to 6 carbon atoms, and a linear or branched alkyl group having 1 to 6 carbon atoms.

Suitable examples of these cation moieties include those represented by the following formulae (a7) and (a8), and the structure represented by the following formula (a8) is particularly preferred.

Such a cationic moiety may be an iodonium salt or a sulfonium salt, but a sulfonium salt is preferable from the standpoint of acid generation efficiency, etc.

Therefore, anions that can form sulfonium salts are preferable as the anion portion of an onium salt that has a naphthalene ring in the cation portion.

The anion portion of such a photoacid generator is a fluoroalkylsulfonate ion or an arylsulfonate ion in which some or all of the hydrogen atoms are fluorinated.

The alkyl group in the fluoroalkylsulfonate ion may be linear, branched, or cyclic and may have 1 to 20 carbon atoms. In view of the bulkiness of the acid generated and its diffusion distance, it is preferable that the alkyl group has 1 to 10 carbon atoms. In particular, branched or cyclic groups are preferable because they have a short diffusion distance. In addition, methyl, ethyl, propyl, butyl, octyl, and the like are preferable because they can be synthesized inexpensively.

The aryl group in the arylsulfonate ion is an aryl group having 6 to 20 carbon atoms, and examples of such groups include alkyl groups, phenyl groups which may or may not be substituted with halogen atoms, and naphthyl groups. In particular, aryl groups having 6 to 10 carbon atoms are preferred because they can be synthesized inexpensively. Specific examples of preferred groups include phenyl groups, toluenesulfonyl groups, ethylphenyl groups, naphthyl groups, and methylnaphthyl groups.

In the above fluoroalkylsulfonate ions or arylsulfonate ions, when some or all of the hydrogen atoms are fluorinated, the fluorination rate is preferably 10% to 100%, more preferably 50% to 100%, and is particularly preferably one in which all hydrogen atoms are replaced with fluorine atoms, since this increases the acid strength. Specific examples of such ions include trifluoromethanesulfonate, perfluorobutanesulfonate, perfluorooctane sulfonate, and perfluorobenzenesulfonate.

Among these, the preferred anion portion is represented by the following formula (a9):

In the above formula (a9), R ^20a is a group represented by the following formulae (a10), (a11), and (a12).

In the above formula (a10), x represents an integer of 1 or more and 4 or less. In addition, in the above formula (a11), R ^21a represents a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having from 1 to 6 carbon atoms, or a linear or branched alkoxy group having from 1 to 6 carbon atoms, and y represents an integer of from 1 to 3. Among these, trifluoromethanesulfonate and perfluorobutanesulfonate are preferred from the viewpoint of safety.

The anion portion may also contain nitrogen, as represented by the following formulae (a13) and (a14).

In the above formulas (a13) and (a14), ^Xa represents a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, and most preferably 3 carbon atoms. ^Ya and ^Za each independently represent a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, and more preferably 1 to 3 carbon atoms.

The smaller the number of carbon atoms in the alkylene group of ^Xa or the number of carbon atoms in the alkyl groups of Y ^a and Z ^a is, the better the solubility in organic solvents is, so it is preferable.

In the alkylene group of ^Xa or the alkyl group of ^Ya and ^Za , the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength, which is preferable. The proportion of fluorine atoms in the alkylene group or alkyl group, i.e., the fluorination rate, is preferably 70% or more and 100% or less, more preferably 90% or more and 100% or less, and most preferably a perfluoroalkylene group or perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.

Preferred onium salts having a naphthalene ring in the cation moiety include compounds represented by the following formulas (a15) and (a16).

A sixth example of a suitable photoacid generator is a bissulfonyldiazomethane such as bis(p-toluenesulfonyl)diazomethane, bis(1,1-dimethylethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, or bis(2,4-dimethylphenylsulfonyl)diazomethane; 2-nitrobenzyl p-toluenesulfonate, 2,6-dinitrobenzyl p-toluenesulfonate, nitrobenzyl tosylate, dinitrobenzyl tosylate, nitrobenzyl sulfonate, nitrobenzyl carbonate, or dinitrobenzyl carbonate; pyrogallol trimesylate, pyrogallol tritosylate, benzyl tosylate, benzyl sulfonate, N-methylsulfonyloxysuccinimide, N-trichloromethylsulfonyloxysuccinimide, N-phenylsulfonyloxymaleimide, N-methylsulfonyloxysuccinim ... Sulfonic acid esters such as hydroxyphthalimide; trifluoromethanesulfonic acid esters such as N-hydroxyphthalimide and N-hydroxynaphthalimide; onium salts such as diphenyliodonium hexafluorophosphate, (4-methoxyphenyl)phenyliodonium trifluoromethanesulfonate, bis(p-tert-butylphenyl)iodonium trifluoromethanesulfonate, triphenylsulfonium hexafluorophosphate, (4-methoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, and (p-tert-butylphenyl)diphenylsulfonium trifluoromethanesulfonate; benzoin tosylate, α-methylbenzoin tosylate, and other benzoin tosylates; other diphenyliodonium salts, triphenylsulfonium salts, phenyldiazonium salts, and benzyl carbonate.

（式（ｃ－５）中、Ｒ^２２ａは、１価の有機基であり、Ｒ^２３ａ、Ｒ^２４ａ、Ｒ^２５ａ、及びＲ^２６ａ、それぞれ独立に、水素原子又は１価の有機基であり、Ｒ^２３ａとＲ^２４ａと、Ｒ^２４ａとＲ^２５ａと、又はＲ^２５ａとＲ^２６ａとは、それぞれ互いに結合して環を形成してもよい。） In addition, a naphthalic acid derivative represented by the following formula (c-5) is also preferable as a photoacid generator.

(In formula (c-5), R ^22a is a monovalent organic group, R ^23a , R ^24a , R ^25a , and R ^26a are each independently a hydrogen atom or a monovalent organic group, and R ^23a and R ^24a , R ^24a and R ^25a , or R ^25a and R ^26a may each be bonded to each other to form a ring.)

The organic group represented by R ^22a is not particularly limited as long as it does not impair the object of the present invention. The organic group may be a hydrocarbon group, and may contain heteroatoms such as O, N, S, P, and halogen atoms. The structure of the organic group may be linear, branched, cyclic, or a combination of these structures.

Examples of the organic group suitable as R ^22a include an aliphatic hydrocarbon group having from 1 to 18 carbon atoms which may be substituted with a halogen atom and/or an alkylthio group, an aryl group having from 6 to 20 carbon atoms which may have a substituent, an aralkyl group having from 7 to 20 carbon atoms which may have a substituent, an alkylaryl group having from 7 to 20 carbon atoms which may have a substituent, a camphor-10-yl group, and a group represented by the following formula (c-5a):
-R ^27a -(O) _a -R ^28a -(O) _b -Y ¹ -R ^29a ...(c-5a)
(In formula (c-5a), Y ¹ is a single bond or an alkanediyl group having from 1 to 4 carbon atoms. R ^27a and R ^28a are each an alkanediyl group having from 2 to 6 carbon atoms which may be substituted with a halogen atom, or an arylene group having from 6 to 20 carbon atoms which may be substituted with a halogen atom. R ^29a is an alkyl group having from 1 to 18 carbon atoms which may be substituted with a halogen atom, an alicyclic hydrocarbon group having from 3 to 12 carbon atoms, an aryl group having from 6 to 20 carbon atoms which may be substituted with a halogen atom, or an aralkyl group having from 7 to 20 carbon atoms which may be substituted with a halogen atom. a and b are each 0 or 1, and at least one of a and b is 1.)
Examples of the group include a group represented by the following formula:

When the organic group represented by R ^22a has a halogen atom as a substituent, examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom and a fluorine atom.

When the organic group represented by R ^22a is an alkyl group having 1 to 18 carbon atoms substituted with an alkylthio group, the alkylthio group preferably has 1 to 18 carbon atoms.
Examples of the alkylthio group having 1 to 18 carbon atoms include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, an n-butylthio group, a sec-butylthio group, a tert-butylthio group, an isobutylthio group, an n-pentylthio group, an isopentylthio group, a tert-pentylthio group, an n-hexylthio group, an n-heptylthio group, an isoheptylthio group, a tert-heptylthio group, an n-octylthio group, an isooctylthio group, a tert-octylthio group, a 2-ethylhexylthio group, an n-nonylthio group, an n-decylthio group, an n-undecylthio group, an n-dodecylthio group, an n-tridecylthio group, an n-tetradecylthio group, an n-pentadecylthio group, an n-hexadecylthio group, an n-heptadecylthio group, and an n-octadecylthio group.

When the organic group represented by R ^22a is an aliphatic hydrocarbon group having from 1 to 18 carbon atoms which may be substituted with a halogen atom and/or an alkylthio group, the aliphatic hydrocarbon group may contain an unsaturated double bond.
The structure of the aliphatic hydrocarbon group is not particularly limited, and may be linear, branched, or cyclic, or may be a combination of these structures.

When the organic group represented by R ^22a is an alkenyl group, preferred examples thereof include an allyl group and a 2-methyl-2-propenyl group.

Preferred examples of the organic group represented by R ^22a that is an alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, an n-hexyl group, an n-hexane-2-yl group, an n-hexane-3-yl group, an n-heptyl group, an n-heptan-2-yl group, an n-hexane-4-yl group, an n-hexane-5-yl group, an n-hexane-6-yl group, an n-hexane-7-yl group, an n-hexane-8-yl group, an n-hexane-9-yl group, an n-hexane-10-yl group, an n-hexane-11-yl group, an n-hexane-12-yl group, an n-hexane-13-yl group, an n-hexane-14-yl group, an n-hexane-15-yl group, an n-hexane-16-yl group, an n-hexane-17-yl group, an n-hexane-18-yl group, an n-hexane-19-yl group, an n-hexane-20-yl group, an n-hexane-21-yl group, an n-hexane-22-yl group, an n-hexane-23-yl group, an n-hexane-24-yl group, an n-hexane-25-yl group, an n-hexane-26-yl group, an n-hexane-37-yl group, an n-hexane-27-yl group, an n-hexane-38-yl group, an n-hexane-25-yl group, an n-hexane-39 ... Examples of the alkyl group include n-heptan-3-yl group, isoheptyl group, tert-heptyl group, n-octyl group, isooctyl group, tert-octyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, and n-octadecyl group.

When the organic group represented by R ^22a is an alicyclic hydrocarbon group, examples of the alicyclic hydrocarbon constituting the main skeleton of the alicyclic hydrocarbon group include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane, bicyclo[3.2.1]octane, bicyclo[2.2.2]octane, and adamantane. As the alicyclic hydrocarbon group, a group in which one hydrogen atom has been removed from these alicyclic hydrocarbons is preferable.

Preferred examples of the organic group represented by R ^22a which is an aliphatic hydrocarbon group substituted with a halogen atom include a trifluoromethyl group, a pentafluoroethyl group, a 2-chloroethyl group, a 2-bromoethyl group, a heptafluoro-n-propyl group, a 3-bromopropyl group, a nonafluoro-n-butyl group, a tridecafluoro-n-hexyl group, a heptadecafluoro-n-octyl group, a 2,2,2-trifluoroethyl group, a 1,1-difluoroethyl group, a 1,1-difluoro-n-propyl group, a 1,1,2,2-tetrafluoro-n-propyl group, a 3,3,3-trifluoro-n-propyl group, a 2,2,3,3,3-pentafluoro-n-propyl group, a 2-norbornyl-1,1-difluoroethyl group, a 2-norbornyltetrafluoroethyl group, and a 3-adamantyl-1,1,2,2-tetrafluoropropyl group.

When the organic group represented by R ^22a is an aliphatic hydrocarbon group substituted with an alkylthio group, preferred examples thereof include a 2-methylthioethyl group, a 4-methylthio-n-butyl group, and a 2-n-butylthioethyl group.

When the organic group represented by R ^22a is an aliphatic hydrocarbon group substituted with a halogen atom and an alkylthio group, a preferred example thereof is 3-methylthio-1,1,2,2-tetrafluoro-n-propyl group.

When the organic group represented by R ^22a is an aryl group, preferred examples thereof include a phenyl group, a naphthyl group, and a biphenylyl group.

When the organic group represented by R ^22a is an aryl group substituted with a halogen atom, preferred examples thereof include a pentafluorophenyl group, a chlorophenyl group, a dichlorophenyl group, and a trichlorophenyl group.

When the organic group represented by R ^22a is an aryl group substituted with an alkylthio group, preferred examples thereof include a 4-methylthiophenyl group, a 4-n-butylthiophenyl group, a 4-n-octylthiophenyl group, and a 4-n-dodecylthiophenyl group.

When the organic group represented by R ^22a is an aryl group substituted with a halogen atom and an alkylthio group, preferred examples thereof include a 1,2,5,6-tetrafluoro-4-methylthiophenyl group, a 1,2,5,6-tetrafluoro-4-n-butylthiophenyl group, and a 1,2,5,6-tetrafluoro-4-n-dodecylthiophenyl group.

When the organic group represented by R ^22a is an aralkyl group, preferred examples thereof include a benzyl group, a phenethyl group, a 2-phenylpropan-2-yl group, a diphenylmethyl group, and a triphenylmethyl group.

When the organic group represented by R ^22a is an aralkyl group substituted with a halogen atom, preferred examples thereof include a pentafluorophenylmethyl group, a phenyldifluoromethyl group, a 2-phenyltetrafluoroethyl group, and a 2-(pentafluorophenyl)ethyl group.

When the organic group represented by R ^22a is an aralkyl group substituted with an alkylthio group, a suitable example thereof is a p-methylthiobenzyl group.

When the organic group represented by R ^22a is an aralkyl group substituted with a halogen atom and an alkylthio group, a preferred example thereof is a 2-(2,3,5,6-tetrafluoro-4-methylthiophenyl)ethyl group.

Preferred examples of the organic group represented by R ^22a when it is an alkylaryl group include a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 3-isopropylphenyl group, a 4-isopropylphenyl group, a 4-n-butylphenyl group, a 4-isobutylphenyl group, a 4-tert-butylphenyl group, a 4-n-hexylphenyl group, a 4-cyclohexylphenyl group, a 4-n-octylphenyl group, a 4-(2-ethyl-n-hexyl)phenyl group, a 2,3-dimethylphenyl group, a 2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, and a 2,6-dimethylphenyl group. group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, a 2,4-di-tert-butylphenyl group, a 2,5-di-tert-butylphenyl group, a 2,6-di-tert-butylphenyl group, a 2,4-di-tert-pentylphenyl group, a 2,5-di-tert-pentylphenyl group, a 2,5-di-tert-octylphenyl group, a 2-cyclohexylphenyl group, a 3-cyclohexylphenyl group, a 4-cyclohexylphenyl group, a 2,4,5-trimethylphenyl group, a 2,4,6-trimethylphenyl group, and a 2,4,6-triisopropylphenyl group.

The group represented by formula (c-5a) is an ether group-containing group.
In formula (c-5a), examples of the alkanediyl group having 1 to 4 carbon atoms represented by ^Y1 include a methylene group, an ethane-1,2-diyl group, an ethane-1,1-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, and a butane-1,2-diyl group.
In formula (c-5a), examples of the alkanediyl group having 2 to 6 carbon atoms represented by R ^27a or R ^28a include an ethane-1,2-diyl group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,2-diyl group, a pentane-1,5-diyl group, a pentane-1,3-diyl group, a pentane-1,4-diyl group, a pentane-2,3-diyl group, a hexane-1,6-diyl group, a hexane-1,2-diyl group, a hexane-1,3-diyl group, a hexane-1,4-diyl group, a hexane-2,5-diyl group, a hexane-2,4-diyl group, and a hexane-3,4-diyl group.

In formula (c-5a), when R ^27a or R ^28a is an alkanediyl group having 2 to 6 carbon atoms substituted with a halogen atom, examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Examples of the alkanediyl group substituted with a halogen atom include a tetrafluoroethane-1,2-diyl group, a 1,1-difluoroethane-1,2-diyl group, a 1-fluoroethane-1,2-diyl group, a 1,2-difluoroethane-1,2-diyl group, a hexafluoropropane-1,3-diyl group, a 1,1,2,2-tetrafluoropropane-1,3-diyl group, and a 1,1,2,2-tetrafluoropentane-1,5-diyl group.

In formula (c-5a), examples of when R ^27a or R ^28a is an arylene group include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a 2,5-dimethyl-1,4-phenylene group, a biphenyl-4,4'-diyl group, a diphenylmethane-4,4'-diyl group, a 2,2,-diphenylpropane-4,4'-diyl group, a naphthalene-1,2-diyl group, a naphthalene-1,3-diyl group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, a naphthalene-1,6-diyl group, a naphthalene-1,7-diyl group, a naphthalene-1,8-diyl group, a naphthalene-2,3-diyl group, a naphthalene-2,6-diyl group, and a naphthalene-2,7-diyl group.

In formula (c-5a), when R ^27a or R ^28a is an arylene group substituted with a halogen atom, examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Examples of the arylene group substituted with a halogen atom include a 2,3,5,6-tetrafluoro-1,4-phenylene group.

In formula (c-5a), examples of the alkyl group having 1 to 18 carbon atoms and which may have a branch and is represented by R ^29a include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, an n-hexyl group, an n-hexane-2-yl group, an n-hexane-3-yl group, an n-heptyl group, an n-heptane-2-yl group, an n-hexane-3-yl group, an n-hexane ... Examples of the aryl group include an n-heptan-3-yl group, an isoheptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a tert-octyl group, a 2-ethylhexyl group, an n-nonyl group, an isononyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, and an n-octadecyl group.

In formula (c-5a), when R ^29a is an alkyl group having 1 to 18 carbon atoms substituted with a halogen atom, examples of the halogen atom include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. Examples of the alkyl group substituted with a halogen atom include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-propyl group, a nonafluoro-n-butyl group, a tridecafluoro-n-hexyl group, a heptadecafluoro-n-octyl group, a 2,2,2-trifluoroethyl group, a 1,1-difluoroethyl group, a 1,1-difluoro-n-propyl group, a 1,1,2,2-tetrafluoro-n-propyl group, a 3,3,3-trifluoro-n-propyl group, a 2,2,3,3,3-pentafluoro-n-propyl group, and a 1,1,2,2-tetrafluorotetradecyl group.

In formula (c-5a), when R ^29a is an alicyclic hydrocarbon group having 3 to 12 carbon atoms, examples of the alicyclic hydrocarbon constituting the main skeleton of the alicyclic hydrocarbon group include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane, bicyclo[3.2.1]octane, bicyclo[2.2.2]octane, and adamantane. As the alicyclic hydrocarbon group, a group in which one hydrogen atom has been removed from these alicyclic hydrocarbons is preferable.

In formula (c-5a), when R ^29a is an aryl group, a halogenated aryl group, an aralkyl group or a halogenated aralkyl group, suitable examples of these groups are the same as those when R ^22a is these groups.

Among the groups represented by formula (c-5a), a preferred group is a group represented by R ^27a in which the carbon atom bonded to a sulfur atom is substituted with a fluorine atom. The number of carbon atoms in such a preferred group is preferably 2 or more and 18 or less.

As R ^22a , a perfluoroalkyl group having from 1 to 8 carbon atoms is preferable. Furthermore, a camphor-10-yl group is also preferable as R ^22a because it facilitates the formation of a highly precise resist pattern.

In formula (c-5), R ^23a to R ^26a are hydrogen atoms or monovalent organic groups. R ^23a and R ^24a , R ^24a and R ^25a , or R ^25a and R ^26a may be bonded to each other to form a ring. For example, R ^25a and R ^26a may be bonded to a naphthalene ring to form a five-membered ring, thereby forming an acenaphthene skeleton.

The monovalent organic group is preferably an alicyclic hydrocarbon group, a heterocyclic group (heterocyclyl group), or an alkoxy group having 4 to 18 carbon atoms which may be substituted with a halogen atom and which may have a branched structure; a heterocyclyloxy group; an alicyclic hydrocarbon group, a heterocyclic group (heterocyclyl group), or an alkylthio group having 4 to 18 carbon atoms which may be substituted with a halogen atom and which may have a branched structure; or a heterocyclylthio group.
Also preferred is a group in which a methylene group at any position not adjacent to the oxygen atom of the alkoxy group is substituted with --CO--.
Also preferred is a group in which the alkoxy group is interrupted by an —O—CO— bond or an —O—CO—NH— bond, where the left end of the —O—CO— bond or the —O—CO—NH— bond is the side closer to the naphthalic acid mother nucleus in the alkoxy group.
Furthermore, alicyclic hydrocarbon groups, heterocyclic groups, or alkylthio groups having 4 to 18 carbon atoms which may be substituted with a halogen atom and which may be branched are also preferred as R ^23a to R ^26a .
Also preferred is an alkylthio group in which a methylene group at any position not adjacent to the sulfur atom is substituted with --CO--.
Also preferred is a group in which the alkylthio group is interrupted by an —O—CO— bond or an —O—CO—NH— bond, in which the left end of the —O—CO— bond or the —O—CO—NH— bond is closer to the naphthalic acid mother nucleus in the alkylthio group.

It is ^{preferable that R 23a to R 26a are an organic group, R 24a to R 26a are} hydrogen atoms, or R ^24a is an organic group, and R ^23a , R ^25a and R ^26a are hydrogen atoms. Also, R ^23a to R ^26a may all be hydrogen atoms.

Examples of groups in which R ^23a to R ^26a are unsubstituted alkoxy groups include a n-butyloxy group, a sec-butyloxy group, a tert-butyloxy group, an isobutyloxy group, a n-pentyloxy group, an isopentyloxy group, a tert-pentyloxy group, a n-hexyloxy group, a n-heptyloxy group, a isoheptyloxy group, a tert-heptyloxy group, a n-octyloxy group, an isooctyloxy group, a tert-octyloxy group, a 2-ethylhexyl group, a n-nonyloxy group, a n-decyloxy group, a n-undecyloxy group, a n-dodecyloxy group, a n-tridecyloxy group, a n-tetradecyloxy group, a n-pentadecyloxy group, a n-hexadecyloxy group, a n-heptadecyloxy group, and a n-octadecyloxy group.

Examples of groups in which R ^23a to R ^26a are unsubstituted alkylthio groups include an n-butylthio group, a sec-butylthio group, a tert-butylthio group, an isobutylthio group, an n-pentylthio group, an isopentylthio group, a tert-pentylthio group, an n-hexylthio group, an n-heptylthio group, an isoheptylthio group, a tert-heptylthio group, an n-octylthio group, an isooctylthio group, a tert-octylthio group, a 2-ethylhexylthio group, an n-nonylthio group, an n-decylthio group, an n-undecylthio group, an n-dodecylthio group, an n-tridecylthio group, an n-tetradecylthio group, an n-pentadecylthio group, an n-hexadecylthio group, an n-heptadecylthio group, and an n-octadecylthio group.

When R ^23a to R ^26a are an alkoxy group or an alkylthio group substituted with an alicyclic hydrocarbon group, examples of the alicyclic hydrocarbon constituting the main skeleton of the alicyclic hydrocarbon group include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane, bicyclo[3.2.1]octane, bicyclo[2.2.2]octane, and adamantane. As the alicyclic hydrocarbon group, a group in which one hydrogen atom has been removed from these alicyclic hydrocarbons is preferable.

When R ^23a to R ^26a are an alkoxy group or an alkylthio group substituted with a heterocyclic group, or when R ^23a to R ^26a are a heterocyclyloxy group, examples of the heterocycle constituting the main skeleton of the heterocyclic group or the heterocyclyloxy group include pyrrole, thiophene, furan, pyran, thiopyran, imidazole, pyrazole, thiazole, isothiazole, oxazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine, pyrrolidine, pyrazolidine, imidazolidine, isoxazolidine, isothiazolidine, piperidine, piperazine, morpholine, thiomorpholine, chroman, thiochroman, isochroman, isothiochroman, indoline, isoindoline, Examples of the heterocyclic ring include pyridine, indolizine, indole, indazole, purine, quinolizine, isoquinoline, quinoline, naphthyridine, phthalazine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, perimidine, phenanthroline, carbazole, carboline, phenazine, anthridine, thiadiazole, oxadiazole, triazine, triazole, tetrazole, benzimidazole, benzoxazole, benzothiazole, benzothiadiazole, benzofuroxan, naphthoimidazole, benzotriazole, and tetraazaindene. Among these heterocyclic rings, saturated heterocyclic rings in which a ring having a conjugated bond is hydrogenated are also preferred.
As the heterocyclic group substituting an alkoxy group or an alkylthio group, or the heterocyclic group contained in a heterocyclyloxy group, a group in which one hydrogen atom has been removed from the above heterocycle is preferable.

Examples of alkoxy groups containing an alicyclic hydrocarbon group each of R ^23a to R ^26a include a cyclopentyloxy group, a methylcyclopentyloxy group, a cyclohexyloxy group, a fluorocyclohexyloxy group, a chlorocyclohexyloxy group, a cyclohexylmethyloxy group, a methylcyclohexyloxy group, a norbornyloxy group, an ethylcyclohexyloxy group, a cyclohexylethyloxy group, a dimethylcyclohexyloxy group, a methylcyclohexylmethyloxy group, a norbornylmethyloxy group, a trimethylcyclohexyloxy group, Examples of such groups include a 1-cyclohexylbutyloxy group, an adamantyloxy group, a menthyloxy group, an n-butylcyclohexyloxy group, a tert-butylcyclohexyloxy group, a bornyloxy group, an isobornyloxy group, a decahydronaphthyloxy group, a dicyclopentadienoxy group, a 1-cyclohexylpentyloxy group, a methyladamantyloxy group, an adamantylmethyloxy group, a 4-pentylcyclohexyloxy group, a cyclohexylcyclohexyloxy group, an adamantylethyloxy group, and a dimethyladamantyloxy group.

When R ^23a to R ^26a are each a heterocyclyloxy group, examples of the heterocyclyloxy group include a tetrahydrofuranyloxy group, a furfuryloxy group, a tetrahydrofurfuryloxy group, a tetrahydropyranyloxy group, a butyrolactonyloxy group, and an indolyloxy group.

When R ^23a to R ^26a are each an alkylthio group containing an alicyclic hydrocarbon group, examples of the alkylthio group include a cyclopentylthio group, a cyclohexylthio group, a cyclohexylmethylthio group, a norbornylthio group, and an isonorbornylthio group.

When R ^23a to R ^26a are each a heterocyclylthio group, examples of the group include a furfurylthio group and a tetrahydrofuranylthio group.

Examples of R ^23a to R ^26a in which a methylene group at any position not adjacent to an oxygen atom of an alkoxy group is substituted with --CO-- include 2-ketobutyl-1-oxy group, 2-ketopentyl-1-oxy group, 2-ketohexyl-1-oxy group, 2-ketoheptyl-1-oxy group, 2-ketooctyl-1-oxy group, 3-ketobutyl-1-oxy group, 4-ketopentyl-1-oxy group, 5-ketohexyl-1-oxy group, 6-ketoheptyl-1-oxy group, 7-ketooctyl-1-oxy group, 3-methyl-2-ketopentane-4-oxy group, 2-ketopentane-4-oxy group, 2-methyl-2-ketopentane-4-oxy group, 3-ketoheptane-5-oxy group and 2-adamantanone-5-oxy group.

Examples of R ^23a to R ^26a which are groups in which a methylene group at any position not adjacent to a sulfur atom of an alkylthio group is substituted with --CO-- include 2-ketobutyl-1-thio group, 2-ketopentyl-1-thio group, 2-ketohexyl-1-thio group, 2-ketoheptyl-1-thio group, 2-ketooctyl-1-thio group, 3-ketobutyl-1-thio group, 4-ketopentyl-1-thio group, 5-ketohexyl-1-thio group, 6-ketoheptyl-1-thio group, 7-ketooctyl-1-thio group, 3-methyl-2-ketopentane-4-thio group, 2-ketopentane-4-thio group, 2-methyl-2-ketopentane-4-thio group, and 3-ketoheptane-5-thio group.

Suitable examples of the naphthalic acid derivative represented by formula (c-5) include the following compounds.

Other examples of the photoacid generator include bis(p-toluenesulfonyl)diazomethane, methylsulfonyl-p-toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1-(1,1-dimethylethylsulfonyl)diazomethane, bis(1,1-dimethylethylsulfonyl)diazomethane, bis(1-methylethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(4-ethylphenylsulfonyl)diazomethane, bis(3-methylphenylsulfonyl)diazomethane, bis(4-methoxyphenylsulfonyl)diazomethane, bis(4-fluorophenylsulfonyl)diazomethane, bis(4-chlorophenylsulfonyl)diazomethane, and bis(4-tert-butylphenylsulfonyl)diazomethane. bissulfonyldiazomethanes such as 2-methyl-2-(p-toluenesulfonyl)propiophenone, 2-(cyclohexylcarbonyl)-2-(p-toluenesulfonyl)propane, 2-methanesulfonyl-2-methyl-(p-methylthio)propiophenone, and 2,4-dimethyl-2-(p-toluenesulfonyl)pentan-3-one; sulfonylcarbonylalkanes such as 1-p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-methylsulfonyl-4-phenyl-2-butanone, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-cyclohexylsulfonyl-3,3-dimethyl-2-butanone, 1-diazo-1-(1,1-dimethylethylsulfonyl)-3,3-dimethyl-2-butanone, 1-acetyl-1-(1 -methylethylsulfonyl)diazomethane, 1-diazo-1-(p-toluenesulfonyl)-3,3-dimethyl-2-butanone, 1-diazo-1-benzenesulfonyl-3,3-dimethyl-2-butanone, 1-diazo-1-(p-toluenesulfonyl)-3-methyl-2-butanone, 2-diazo-2-(p-toluenesulfonyl)cyclohexyl acetate, 2-diazo-2-benzenesulfonylacetate-tert-butyl, 2-diazo-2-methanesulfonylacetate isopropyl, 2-diazo-2-benzenesulfonylacetate cyclohexyl, 2-diazo-2-(p-toluenesulfonyl)sulfonyl acetate-tert-butyl, and other sulfonylcarbonyldiazomethanes; p-toluenesulfonate-2-nitrobenzyl, p-toluenesulfonate-2,6-dinitrobenzyl, p-trifluoromethylbenzenesulfonate-2,4-di nitrobenzyl derivatives such as nitrobenzyl; esters of polyhydroxy compounds and aliphatic or aromatic sulfonic acids such as methanesulfonate esters of pyrogallol, benzenesulfonate esters of pyrogallol, p-toluenesulfonate esters of pyrogallol, p-methoxybenzenesulfonate esters of pyrogallol, mesitylenesulfonate esters of pyrogallol, benzylsulfonate esters of pyrogallol, methanesulfonate esters of alkyl gallates, benzenesulfonate esters of alkyl gallates, p-toluenesulfonate esters of alkyl gallates, p-methoxybenzenesulfonate esters of alkyl gallates (the number of carbon atoms in the alkyl group is 1 to 15), mesitylenesulfonate esters of alkyl gallates, and benzylsulfonate esters of alkyl gallates; and the like.
These photoacid generators may be used alone or in combination of two or more kinds.

The photoacid generator may be used alone or in combination of two or more kinds. The content of the photoacid generator is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 3% by mass or less, based on the total mass of the photosensitive composition of the second embodiment. By setting the amount of the photoacid generator used within the above range, it is easy to prepare the photosensitive composition of the second embodiment, which has good sensitivity, is a homogeneous solution, and has excellent storage stability.

The resin whose solubility in alkali increases under the action of an acid is not particularly limited, and any resin whose solubility in alkali increases under the action of an acid can be used. Among them, it is preferable to contain at least one resin selected from the group consisting of novolac resin (B1), polyhydroxystyrene resin (B2), and acrylic resin (B3).

[Novolac resin (B1)]
As the novolak resin (B1), a resin containing a structural unit represented by the following formula (b1) can be used.

In the above formula (b1), R ^1b represents an acid dissociable, dissolution inhibiting group, and R ^2b and R ^3b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

The acid dissociable, dissolution inhibiting group represented by R ^1b above is preferably a group represented by the following formula (b2) or (b3), a linear, branched, or cyclic alkyl group having from 1 to 6 carbon atoms, a vinyloxyethyl group, a tetrahydropyranyl group, a tetrafuranyl group, or a trialkylsilyl group.

In the above formulas (b2) and (b3), R ^4b and R ^5b each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms; R ^6b represents a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms; R ^7b represents a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms; and o represents 0 or 1.

Examples of the linear or branched alkyl group include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups. Examples of the cyclic alkyl group include cyclopentyl and cyclohexyl groups.

Specific examples of the acid dissociable dissolution inhibiting group represented by the above formula (b2) include methoxyethyl, ethoxyethyl, n-propoxyethyl, isopropoxyethyl, n-butoxyethyl, isobutoxyethyl, tert-butoxyethyl, cyclohexyloxyethyl, methoxypropyl, ethoxypropyl, 1-methoxy-1-methyl-ethyl, and 1-ethoxy-1-methylethyl groups. Specific examples of the acid dissociable dissolution inhibiting group represented by the above formula (b3) include tert-butoxycarbonyl and tert-butoxycarbonylmethyl groups. Examples of the trialkylsilyl group include trimethylsilyl and tri-tert-butyldimethylsilyl groups, each of which has 1 to 6 carbon atoms in the alkyl group.

[Polyhydroxystyrene resin (B2)]
As the polyhydroxystyrene resin (B2), a resin containing a structural unit represented by the following formula (b4) can be used.

In the above formula (b4), R ^8b represents a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms, and R ^9b represents an acid dissociable, dissolution inhibiting group.

The alkyl group having 1 to 6 carbon atoms is, for example, a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms. Examples of linear or branched alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and neopentyl groups, and examples of cyclic alkyl groups include cyclopentyl and cyclohexyl groups.

As the acid dissociable, dissolution inhibiting group represented by R ^9b , the same acid dissociable, dissolution inhibiting groups as exemplified in formulae (b2) and (b3) above can be used.

Furthermore, the polyhydroxystyrene resin (B2) may contain other polymerizable compounds as structural units in order to appropriately control the physical and chemical properties. Examples of such polymerizable compounds include known radically polymerizable compounds and anionically polymerizable compounds. Examples of such polymerizable compounds include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; methacrylic acid derivatives having a carboxy group and an ester bond such as 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; phenyl methacrylate, ... (Meth)acrylic acid aryl esters such as benzyl (meth)acrylate and benzyl (meth)acrylate; dicarboxylic acid diesters such as diethyl maleate and dibutyl fumarate; vinyl group-containing aromatic compounds such as styrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, vinyltoluene, hydroxystyrene, α-methylhydroxystyrene, and α-ethylhydroxystyrene; vinyl group-containing aliphatic compounds such as vinyl acetate; conjugated diolefins such as butadiene and isoprene; nitrile group-containing polymerizable compounds such as acrylonitrile and methacrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; and the like.

[Acrylic resin (B3)]
As the acrylic resin (B3), resins containing structural units represented by the following formulas (b5) to (b7) can be used.

In the above formulas (b5) to (b7), R ^10b and R ^14b to R ^19b each independently represent a hydrogen atom, a linear or branched alkyl group having from 1 to 6 carbon atoms, a fluorine atom, or a linear or branched fluorinated alkyl group having from 1 to 6 carbon atoms; R ^11b to R ^13b each independently represent a linear or branched alkyl group having from 1 to 6 carbon atoms, a linear or branched fluorinated alkyl group having from 1 to 6 carbon atoms, or an aliphatic cyclic group having from 5 to 20 carbon atoms; R ^12b and R ^13b may be bonded to each other to form a hydrocarbon ring having from 5 to 20 carbon atoms together with the carbon atom to which they are bonded; Y ^b represents an aliphatic cyclic group or an alkyl group which may have a substituent; p represents an integer of 0 to 4; and q represents 0 or 1.

Examples of the linear or branched alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, etc. A fluorinated alkyl group is an alkyl group in which some or all of the hydrogen atoms are substituted with fluorine atoms.
Specific examples of the aliphatic cyclic group include groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as monocycloalkanes, bicycloalkanes, tricycloalkanes, and tetracycloalkanes. Specific examples include groups in which one hydrogen atom has been removed from monocycloalkanes such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. In particular, groups in which one hydrogen atom has been removed from cyclohexane and adamantane (which may further have a substituent) are preferred.

When R ^12b and R ^13b are not bonded to each other to form a hydrocarbon ring, R ^11b , R ^12b and R ^13b are preferably linear or branched alkyl groups having 2 to 4 carbon atoms in terms of high contrast, good resolution, focal depth range, etc. R ^15b , R ^16b , R ^18b and R ^19b are preferably hydrogen atoms or methyl groups.

The above R ^12b and R ^13b may form an aliphatic cyclic group having 5 to 20 carbon atoms together with the carbon atom to which they are bonded. Specific examples of such aliphatic cyclic groups include groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as monocycloalkanes, bicycloalkanes, tricycloalkanes, and tetracycloalkanes. Specific examples include groups in which one or more hydrogen atoms have been removed from monocycloalkanes such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. In particular, groups in which one or more hydrogen atoms have been removed from cyclohexane and adamantane (which may further have a substituent) are preferred.

Furthermore, when the aliphatic cyclic group formed by R ^12b and R ^13b has a substituent on its ring skeleton, examples of the substituent include polar groups such as a hydroxyl group, a carboxyl group, a cyano group, and an oxygen atom (=O), and a linear or branched alkyl group having 1 to 4 carbon atoms. As the polar group, an oxygen atom (=O) is particularly preferable.

The above ^Yb is an aliphatic cyclic group or an alkyl group, and examples thereof include groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as monocycloalkanes, bicycloalkanes, tricycloalkanes, and tetracycloalkanes. Specific examples thereof include groups in which one or more hydrogen atoms have been removed from monocycloalkanes such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. In particular, groups in which one or more hydrogen atoms have been removed from adamantane (which may further have a substituent) are preferred.

Furthermore, when the aliphatic cyclic group of ^Yb has a substituent on its ring skeleton, examples of the substituent include polar groups such as a hydroxyl group, a carboxyl group, a cyano group, and an oxygen atom (=O), and linear or branched alkyl groups having from 1 to 4 carbon atoms. As the polar group, an oxygen atom (=O) is particularly preferable.

Furthermore, when Y ^b is an alkyl group, it is preferably a linear or branched alkyl group having from 1 to 20 carbon atoms, and preferably from 6 to 15. Such an alkyl group is particularly preferably an alkoxyalkyl group, and examples of such an alkoxyalkyl group include a 1-methoxyethyl group, a 1-ethoxyethyl group, a 1-n-propoxyethyl group, a 1-isopropoxyethyl group, a 1-n-butoxyethyl group, a 1-isobutoxyethyl group, a 1-tert-butoxyethyl group, a 1-methoxypropyl group, a 1-ethoxypropyl group, a 1-methoxy-1-methyl-ethyl group, and a 1-ethoxy-1-methylethyl group.

Specific preferred examples of the structural unit represented by formula (b5) above include structural units represented by the following formulas (b5-1) to (b5-33).

In the above formulas (b5-1) to (b5-33), R ^20b represents a hydrogen atom or a methyl group.

Specific preferred examples of the structural unit represented by formula (b6) above include structural units represented by the following formulas (b6-1) to (b6-25):

In the above formulae (b6-1) to (b6-25), R ^20b represents a hydrogen atom or a methyl group.

Specific preferred examples of the structural unit represented by formula (b7) above include structural units represented by the following formulas (b7-1) to (b7-15).

In the above formulas (b7-1) to (b7-15), R ^20b represents a hydrogen atom or a methyl group.

Furthermore, it is preferable that the acrylic resin (B3) is a resin made of a copolymer that further contains a structural unit derived from a polymerizable compound having an ether bond in addition to the structural units represented by the above formulas (b5) to (b7).

Examples of the polymerizable compound having an ether bond include radical polymerizable compounds such as (meth)acrylic acid derivatives having an ether bond and an ester bond. Specific examples include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate. In addition, the polymerizable compound having an ether bond is preferably 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, or methoxytriethylene glycol (meth)acrylate. These polymerizable compounds may be used alone or in combination of two or more.

Furthermore, the acrylic resin (B3) may contain other polymerizable compounds as structural units in order to appropriately control the physical and chemical properties. Examples of such polymerizable compounds include known radical polymerizable compounds and anionically polymerizable compounds.

Examples of such polymerizable compounds include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; methacrylic acid derivatives having a carboxy group and an ester bond such as 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and cyclohexyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. esters; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl (meth)acrylate; dicarboxylic acid diesters such as diethyl maleate and dibutyl fumarate; vinyl group-containing aromatic compounds such as styrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, vinyltoluene, hydroxystyrene, α-methylhydroxystyrene, and α-ethylhydroxystyrene; vinyl group-containing aliphatic compounds such as vinyl acetate; conjugated diolefins such as butadiene and isoprene; nitrile group-containing polymerizable compounds such as acrylonitrile and methacrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; and the like.

In addition, examples of the polymerizable compound include (meth)acrylic acid esters having an acid-non-dissociable aliphatic polycyclic group, vinyl group-containing aromatic compounds, and the like. As the acid-non-dissociable aliphatic polycyclic group, tricyclodecanyl group, adamantyl group, tetracyclododecanyl group, isobornyl group, norbornyl group, and the like are particularly preferred in terms of industrial availability. These aliphatic polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

Specific examples of (meth)acrylic acid esters having an acid-non-dissociable aliphatic polycyclic group include (meth)acrylic acid esters that give structural units of the following formulae (b8-1) to (b8-5).

In the above formulae (b8-1) to (b8-5), R ^21b represents a hydrogen atom or a methyl group.

Among the above photosensitive resins, it is preferable to use acrylic resin (B3). Among such acrylic resins (B3), it is preferable to use a copolymer having a structural unit represented by the above formula (b5), a structural unit derived from (meth)acrylic acid, a structural unit derived from (meth)acrylic acid alkyl esters, and a structural unit derived from (meth)acrylic acid aryl esters.

Such a copolymer is preferably a copolymer represented by the following formula (b9):

In the above formula (b9), R ^22b represents a hydrogen atom or a methyl group, R ^23b represents a linear or branched alkyl group having from 2 to 4 carbon atoms, ^Xb represents a hydrocarbon ring having from 5 to 20 carbon atoms formed together with the carbon atom to which it is bonded, R ^24b represents a linear or branched alkyl group having from 1 to 6 carbon atoms or an alkoxyalkyl group having from 1 to 6 carbon atoms, and R ^25b represents an aryl group having from 6 to 12 carbon atoms.

Furthermore, in the copolymer represented by the above formula (b9), s, t, u, and v represent the molar ratios of the respective structural units, where s is 8 mol% or more and 45 mol% or less, t is 10 mol% or more and 65 mol% or less, u is 3 mol% or more and 25 mol% or less, and v is 6 mol% or more and 25 mol% or less.

The polystyrene-equivalent mass average molecular weight of the photosensitive resin is preferably 10,000 or more and 600,000 or less, more preferably 20,000 or more and 400,000 or less, and even more preferably 30,000 or more and 300,000 or less. By setting the mass average molecular weight in this range, it is easy to maintain sufficient strength of the metal oxide-containing film without reducing the peelability from the substrate surface.

The photosensitive resin is preferably a resin with a dispersity of 1.05 or more. Here, dispersity is the value obtained by dividing the mass average molecular weight by the number average molecular weight. By achieving such a dispersity, it is easy to form a metal oxide-containing film that has excellent stress resistance against the desired plating.

The resin content is preferably 5% by mass or more and 60% by mass or less based on the total mass of the energy-sensitive composition of the second embodiment.

The energy-sensitive composition of the second embodiment preferably further contains an alkali-soluble resin in order to improve crack resistance.
The alkali-soluble resin is preferably at least one resin selected from the group consisting of novolak resins (C1), polyhydroxystyrene resins (C2), and acrylic resins (C3).

[Novolac resin (C1)]
Novolak resins can be obtained, for example, by addition condensation of aromatic compounds having a phenolic hydroxyl group (hereinafter simply referred to as "phenols") with aldehydes in the presence of an acid catalyst.

Examples of the phenols include phenol, o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, o-butylphenol, m-butylphenol, p-butylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, p-phenylphenol, resorcinol, hydroquinone, hydroquinone monomethyl ether, pyrogallol, phloroglucinol, hydroxydiphenyl, bisphenol A, gallic acid, gallic acid esters, α-naphthol, and β-naphthol.
Examples of the aldehydes include formaldehyde, furfural, benzaldehyde, nitrobenzaldehyde, and acetaldehyde.
The catalyst used in the addition condensation reaction is not particularly limited, but for example, hydrochloric acid, nitric acid, sulfuric acid, formic acid, oxalic acid, acetic acid, etc. are used as acid catalysts.

The flexibility of novolac resin can be further improved by using o-cresol, by substituting the hydrogen atoms of the hydroxyl groups in the resin with other substituents, or by using bulky aldehydes.

The mass average molecular weight of the novolac resin (C1) is not particularly limited as long as it does not impair the object of the present invention, but is preferably 1,000 or more and 50,000 or less.

[Polyhydroxystyrene resin (C2)]
Examples of the hydroxystyrene-based compound constituting the polyhydroxystyrene resin (C2) include p-hydroxystyrene, α-methylhydroxystyrene, and α-ethylhydroxystyrene.
Furthermore, the polyhydroxystyrene resin (C2) is preferably a copolymer with a styrene resin. Examples of the styrene-based compound constituting such a styrene resin include styrene, chlorostyrene, chloromethylstyrene, vinyltoluene, and α-methylstyrene.

The mass average molecular weight of the polyhydroxystyrene resin (C2) is not particularly limited as long as it does not impair the object of the present invention, but is preferably 1,000 or more and 50,000 or less.

[Acrylic resin (C3)]
The acrylic resin (C3) preferably contains a structural unit derived from a polymerizable compound having an ether bond and a structural unit derived from a polymerizable compound having a carboxy group, or contains a structural unit derived from a polymerizable compound having a phenolic hydroxyl group, such as 4-hydroxyphenyl (meth)acrylate.

Examples of the polymerizable compound having an ether bond include (meth)acrylic acid derivatives having an ether bond and an ester bond, such as 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate. The polymerizable compound having an ether bond is preferably 2-methoxyethyl acrylate or methoxytriethylene glycol acrylate. These polymerizable compounds may be used alone or in combination of two or more.

Examples of the polymerizable compound having a carboxy group include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; and compounds having a carboxy group and an ester bond such as 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid. The polymerizable compound having a carboxy group is preferably acrylic acid or methacrylic acid. These polymerizable compounds may be used alone or in combination of two or more.

The mass average molecular weight of the acrylic resin (C3) is not particularly limited as long as it does not impair the object of the present invention, but is preferably 50,000 or more and 800,000 or less.

The content of the alkali-soluble resin is preferably 0 parts by mass or more and 80 parts by mass or less, and more preferably 0 parts by mass or more and 60 parts by mass or less, assuming that the total of the photosensitive resin and the alkali-soluble resin is 100 parts by mass. By setting the content of the alkali-soluble resin within the above range, crack resistance is improved and film loss during development tends to be prevented.

The energy-sensitive resin composition of the second embodiment preferably further contains an acid diffusion control agent in order to improve the laying stability of the film made of the photosensitive composition. The acid diffusion control agent is preferably a nitrogen-containing compound (D1), and may further contain an organic carboxylic acid, or a phosphorus oxoacid or a derivative thereof (D2) as necessary.

[Nitrogen-containing compound (D1)]
Examples of the nitrogen-containing compound (D1) include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tri-n-pentylamine, tribenzylamine, diethanolamine, triethanolamine, and n-hexylamine. , n-heptylamine, n-octylamine, n-nonylamine, ethylenediamine, N,N,N',N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4 '-Diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, formamide, N-methylformamide, N,N- Dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3 , 3,-tetramethylurea, 1,3-diphenylurea, imidazole, benzimidazole, 4-methylimidazole, 8-oxyquinoline, acridine, purine, pyrrolidine, piperidine, 2,4,6-tri(2-pyridyl) Examples of the compound include -S-triazine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, and pyridine. These compounds may be used alone. Two or more of them may be used in combination.

The nitrogen-containing compound (D1) is usually used in the range of 0 to 5 parts by mass, and particularly preferably in the range of 0 to 3 parts by mass, per 100 parts by mass of the total mass of the photosensitive resin and the alkali-soluble resin.

[Organic carboxylic acid, phosphorus oxoacid or derivative thereof (D2)]
Of the organic carboxylic acids, phosphorus oxoacids or derivatives thereof (D2), specifically, suitable organic carboxylic acids include malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, etc., with salicylic acid being particularly preferred.

Examples of phosphorus oxoacids or derivatives thereof include phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester, and other phosphoric acid and ester-like derivatives thereof; phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, and other phosphonic acid and ester-like derivatives thereof; phosphinic acid, phosphinic acid phenylphosphinic acid, and other ester-like derivatives thereof; and the like. Among these, phosphonic acid is particularly preferred. These may be used alone or in combination of two or more.

The organic carboxylic acid, or phosphorus oxoacid or its derivative (D2) is usually used in the range of 0 to 5 parts by mass, and particularly preferably in the range of 0 to 3 parts by mass, per 100 parts by mass of the total mass of the photosensitive resin and the alkali-soluble resin.

In order to form a salt and stabilize it, it is preferable to use an organic carboxylic acid, or a phosphorus oxoacid or its derivative (D2) in an amount equal to that of the nitrogen-containing compound (D1).

The energy-sensitive composition of the second embodiment contains an organic solvent. The type of organic solvent is not particularly limited as long as it does not impair the object of the present invention, and can be appropriately selected from organic solvents that have been conventionally used in positive-type photosensitive resin compositions.

Specific examples of organic solvents include, in addition to the solvents listed in the photosensitive composition of the first embodiment, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and derivatives thereof such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, and the monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether of dipropylene glycol monoacetate; dioxanes, dibutyl ether ... Examples of the esters include cyclic ethers such as ethyl formate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl pyruvate, ethyl ethoxyacetate, methyl methoxypropionate, ethyl ethoxypropionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, and 3-methyl-3-methoxybutyl acetate; and aromatic hydrocarbons such as toluene and xylene. These may be used alone or in a mixture of two or more.

The content of the organic solvent is not particularly limited as long as it does not impair the object of the present invention, and may be appropriately adjusted so that, for example, the solid content of the positive photosensitive resin composition is in the range of 2% by mass to 55% by mass. When the photosensitive composition is used for thick film applications in which the thickness of the photosensitive resin layer obtained by spin coating or the like is 10 μm or more, it is preferable to use an organic solvent in the range in which the solid content of the photosensitive resin composition is in the range of 30% by mass to 55% by mass.

The energy-sensitive composition of the second embodiment may further contain a polyvinyl resin to improve plasticity. Specific examples of polyvinyl resins include polyvinyl chloride, polystyrene, polyhydroxystyrene, polyvinyl acetate, polyvinyl benzoic acid, polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl phenol, and copolymers thereof. The polyvinyl resin is preferably polyvinyl methyl ether because of its low glass transition point.

The energy-sensitive composition of the second embodiment may further contain an adhesion aid to improve adhesion between the metal oxide-containing film formed using the photosensitive composition and a substrate, particularly a metal substrate.

The second energy-sensitive composition may further contain an acid, an acid anhydride, or a high-boiling point solvent to fine-tune its solubility in the developer.

Specific examples of acids and acid anhydrides include monocarboxylic acids such as acetic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, benzoic acid, and cinnamic acid; hydroxymonocarboxylic acids such as lactic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 2-hydroxycinnamic acid, 3-hydroxycinnamic acid, 4-hydroxycinnamic acid, 5-hydroxyisophthalic acid, and syringic acid; oxalic acid, succinic acid, glutaric acid, adipic acid, maleic acid, itaconic acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, butanetetracarboxylic acid, and trimellitic acid. Examples of the acid anhydrides include polyvalent carboxylic acids such as itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenylsuccinic anhydride, tricarbanilic anhydride, maleic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, himic anhydride, 1,2,3,4-butanetetracarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bistrimellitate anhydride, and glycerin tristrimellitate anhydride.

Specific examples of high-boiling point solvents include N-methylformamide, N,N-dimethylformamide, N-methylformanilide, N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, benzyl ethyl ether, dihexyl ether, acetonylacetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate.

The energy-sensitive composition of the second embodiment may further contain a sensitizer to improve sensitivity.

(3) Energy-sensitive composition of the third embodiment The energy-sensitive composition of the third embodiment is a negative-type photosensitive composition that contains a metal oxide (A), an alkali-soluble resin having a phenolic hydroxyl group as a base component (B), an acid crosslinking substance, a photoacid generator, and an organic solvent.

As the alkali-soluble resin having a phenolic hydroxyl group in the energy-sensitive composition of the third embodiment, for example, a polyhydroxystyrene-based resin can be used.
The polyhydroxystyrene-based resin has at least a structural unit derived from hydroxystyrene.
Here, the term "hydroxystyrene" is used as a concept that includes hydroxystyrene, hydroxystyrene in which the hydrogen atom bonded to the α-position is substituted with another substituent such as a halogen atom, an alkyl group, or a halogenated alkyl group, and hydroxystyrene derivatives (monomers) of these derivatives.
The "hydroxystyrene derivative" at least maintains the benzene ring and the hydroxyl group bonded thereto, and includes, for example, those in which the hydrogen atom bonded to the α-position of hydroxystyrene has been replaced with another substituent such as a halogen atom, an alkyl group having from 1 to 5 carbon atoms, or a halogenated alkyl group, as well as those in which an alkyl group having from 1 to 5 carbon atoms is further bonded to the benzene ring to which the hydroxyl group of hydroxystyrene is bonded, and those in which one to two hydroxyl groups are further bonded to the benzene ring to which the hydroxyl group is bonded (in this case, the total number of hydroxyl groups is 2 to 3).
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, with a fluorine atom being preferred.
Unless otherwise specified, the "α-position of hydroxystyrene" refers to the carbon atom to which the benzene ring is bonded.

The structural unit derived from this hydroxystyrene is represented, for example, by the following formula (b-1).

In the above formula (b-1), R ^b1 represents a hydrogen atom, an alkyl group, a halogen atom, or a halogenated alkyl group, R ^b2 represents an alkyl group having 1 to 5 carbon atoms, p represents an integer of 1 to 3, and q represents an integer of 0 to 2.

The alkyl group of R ^b1 preferably has 1 to 5 carbon atoms. In addition, a linear or branched alkyl group is preferable, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Of these, a methyl group is preferable from an industrial viewpoint.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred.
The halogenated alkyl group is a group in which some or all of the hydrogen atoms of the above-mentioned alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Among these, an alkyl group in which all of the hydrogen atoms are substituted with fluorine atoms is preferred. Furthermore, a linear or branched fluorinated alkyl group is preferred, with a trifluoromethyl group, a hexafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, and the like being more preferred, and a trifluoromethyl group (-CF ₃ ) being the most preferred.
R ^b1 is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

Examples of the alkyl group having 1 to 5 carbon atoms for R ^b2 include the same groups as those for R ^b1 .
q is an integer of 0 to 2. Among these, 0 or 1 is preferable, and 0 is particularly preferable from an industrial viewpoint.
When q is 1, the substitution position of R ^b2 may be any one of the ortho-position, meta-position, and para-position, and when q is 2, any combination of substitution positions can be used.
p is an integer of 1 to 3, and is preferably 1.
The substitution position of the hydroxyl group may be any of the ortho, meta, and para positions when p is 1, but the para position is preferred because it is easily available and inexpensive. Furthermore, when p is 2 or 3, any combination of substitution positions can be used.

The structural unit represented by the above formula (b-1) can be used alone or in combination of two or more types.

In the polyhydroxystyrene resin, the proportion of the structural units derived from hydroxystyrene is preferably 60 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and even more preferably 80 mol% or more and 100 mol% or less, based on the total structural units constituting the polyhydroxystyrene resin. By keeping it within the above range, appropriate alkali solubility can be obtained when it is made into a photosensitive composition.

The polyhydroxystyrene-based resin preferably further contains a structural unit derived from styrene.
Here, the term "structural unit derived from styrene" is defined to include structural units formed by cleavage of the ethylenic double bond of styrene and styrene derivatives (however, hydroxystyrene is not included).
The term "styrene derivative" is defined to include derivatives in which the hydrogen atom bonded to the α-position of styrene is substituted with other substituents such as a halogen atom, an alkyl group, or a halogenated alkyl group, as well as derivatives in which the hydrogen atom of the phenyl group of styrene is substituted with a substituent such as an alkyl group having 1 to 5 carbon atoms.
Examples of the halogen atom include a chlorine atom, a fluorine atom, and a bromine atom, with a fluorine atom being preferred.
Unless otherwise specified, the "α-position of styrene" refers to the carbon atom to which the benzene ring is bonded.

The structural unit derived from styrene is represented, for example, by the following formula (b-2): In the formula, R ^b1 , R ^b2 and q are as defined above in formula (b-1).

Examples of R ^b1 and R ^b2 include the same groups as R ^b1 and R ^b2 in the above formula (b-1), respectively.
q is an integer of 0 to 2. Among these, 0 or 1 is preferable, and 0 is particularly preferable from an industrial viewpoint.
When q is 1, the substitution position of R ^b2 may be any one of the ortho-position, meta-position, and para-position, and when q is 2, any combination of substitution positions can be used.

The structural unit represented by the above formula (b-2) can be used alone or in combination of two or more types.

In the polyhydroxystyrene resin, the proportion of structural units derived from styrene is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less, based on the total structural units constituting the polyhydroxystyrene resin. By keeping it within the above range, a photosensitive composition can be obtained that has appropriate alkali solubility and is well balanced with other structural units.

The polyhydroxystyrene resin may have other structural units than structural units derived from hydroxystyrene and structural units derived from styrene. More preferably, the polyhydroxystyrene resin is a polymer consisting only of structural units derived from hydroxystyrene, or a copolymer consisting of structural units derived from hydroxystyrene and structural units derived from styrene.

The mass average molecular weight of the polyhydroxystyrene resin is not particularly limited, but is preferably 1,500 or more and 40,000 or less, and more preferably 2,000 or more and 8,000 or less.

Novolac resins can also be used as alkali-soluble resins having phenolic hydroxyl groups. These novolac resins can be obtained by addition condensation of phenols and aldehydes in the presence of an acid catalyst.

Examples of phenols include cresols such as phenol, o-cresol, m-cresol, and p-cresol; xylenols such as 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol; alkane compounds such as o-ethylphenol, m-ethylphenol, p-ethylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, o-butylphenol, m-butylphenol, p-butylphenol, and p-tert-butylphenol. alkylphenols, trialkylphenols such as 2,3,5-trimethylphenol and 3,4,5-trimethylphenol, polyhydric phenols such as resorcinol, catechol, hydroquinone, hydroquinone monomethyl ether, pyrogallol and phloroglucinol, alkyl polyhydric phenols (the alkyl group contained in the alkyl polyhydric phenols has 1 to 4 carbon atoms), such as alkylresorcin, alkylcatechol and alkylhydroquinone, α-naphthol, β-naphthol, hydroxydiphenyl and bisphenol A. These phenols can be used alone or in combination of two or more kinds.
Among these phenols, m-cresol and p-cresol are preferred, and it is more preferred to use m-cresol and p-cresol in combination. In this case, various properties such as sensitivity can be adjusted by adjusting the blending ratio of the two.

Examples of aldehydes include formaldehyde, paraformaldehyde, furfural, benzaldehyde, nitrobenzaldehyde, acetaldehyde, etc. These aldehydes can be used alone or in combination of two or more kinds.

Examples of acid catalysts include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and phosphorous acid; organic acids such as formic acid, oxalic acid, acetic acid, diethylsulfuric acid, and paratoluenesulfonic acid; and metal salts such as zinc acetate. These acid catalysts can be used alone or in combination of two or more.

Specific examples of novolac resins obtained in this manner include phenol/formaldehyde condensation novolac resin, cresol/formaldehyde condensation novolac resin, and phenol-naphthol/formaldehyde condensation novolac resin.

The mass average molecular weight of the novolac resin is not particularly limited, but is preferably from 1,000 to 30,000, and more preferably from 3,000 to 25,000.

Also, examples of alkali-soluble resins having phenolic hydroxyl groups include phenol-xylylene glycol condensation resins, cresol-xylylene glycol condensation resins, and phenol-dicyclopentadiene condensation resins.

The content of the alkali-soluble resin having a phenolic hydroxyl group is preferably 20% by mass or more and 80% by mass or less, and more preferably 35% by mass or more and 65% by mass or less, based on the solid content of the photosensitive composition of the third embodiment. By setting the content within the above range, it tends to be easier to balance the developability.

The acid cross-linking substance in the energy-sensitive composition of the third embodiment is not particularly limited, and any conventionally known acid cross-linking substance can be used.

Specific examples of acid crosslinking substances include amino resins having hydroxyl groups or alkoxyl groups, such as melamine resins, urea resins, guanamine resins, acetoguanamine resins, benzoguanamine resins, glycoluril-formaldehyde resins, succinylamide-formaldehyde resins, and ethyleneurea-formaldehyde resins. These acid crosslinking substances can be easily obtained by reacting melamine, urea, guanamine, acetoguanamine, benzoguanamine, glycoluril, succinylamide, or ethyleneurea with formalin in boiling water to methylolate, or by further reacting this with a lower alcohol to alkoxylate. For practical purposes, they can be obtained as melamine resins such as Nikalac MX-750, Nikalac MW-30, and Nikalac MW100LM, and urea resins such as Nikalac MX-290 (all manufactured by Sanwa Chemical Co., Ltd.). Benzoguanamine resins such as Cymel 1123 and Cymel 1128 (manufactured by Mitsui Cyanad Co., Ltd.) are also available commercially.

In addition, benzene compounds having an alkoxyl group, such as 1,3,5-tris(methoxymethoxy)benzene, 1,2,4-tris(isopropoxymethoxy)benzene, and 1,4-bis(sec-butoxymethoxy)benzene, and phenol compounds having a hydroxyl group or an alkoxyl group, such as 2,6-dihydroxymethyl-p-tert-butylphenol, can also be used.
These acid crosslinking substances can be used alone or in combination of two or more kinds.

The content of the acid crosslinking substance is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of the alkali-soluble resin having a phenolic hydroxyl group. By setting the content within the above range, the curing property and patterning characteristics of the photosensitive composition are improved.

The photoacid generator in the energy-sensitive composition of the third embodiment is not particularly limited, and any conventionally known photoacid generator can be used. Preferred photoacid generators include the photoacid generators described for the second energy-sensitive composition.

The content of the photoacid generator is preferably 0.05 parts by mass or more and 30 parts by mass or less, and more preferably 0.1 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the alkali-soluble resin having a phenolic hydroxyl group. By setting the content within the above range, the curability of the photosensitive composition is improved.

As described above, the energy-sensitive composition of the third embodiment contains a metal oxide (A). Therefore, a patterned metal oxide-containing film can be formed using the energy-sensitive composition of the third embodiment.

The energy-sensitive composition of the third embodiment may further contain a compound having four or more phenolic hydroxyl groups and a molecular weight of less than 2000.

Specific examples of such compounds include benzophenone compounds such as various tetrahydroxybenzophenones, pentahydroxybenzophenones, hexahydroxybenzophenones, and heptahydroxybenzophenones, as well as bis[2-hydroxy-3-(2'-hydroxy-5'-methylbenzyl)-5-methylphenyl]methane, bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, bis(3-cyclohexyl-4-hydroxy-6-methylphenyl)-3,4-dihydroxyphenylmethane, hydroxyaryl compounds such as 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane and 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane; polyhydroxystyrene compounds such as poly(o-hydroxystyrene), poly(m-hydroxystyrene), poly(p-hydroxystyrene), poly(α-methyl-p-hydroxystyrene), and poly(4-hydroxy-3-methylstyrene) having a molecular weight of less than 2000; and the like. These benzophenone compounds, hydroxyaryl compounds, bis(hydroxyphenyl)alkane compounds, and polyhydroxystyrene compounds may have a substituent other than a hydroxyl group.
These compounds may be used alone or in combination of two or more.

The content of the compound having 4 or more phenolic hydroxyl groups and a molecular weight of less than 2000 is preferably 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the alkali-soluble resin having a phenolic hydroxyl group. By setting the content within the above range, it is possible to suppress the tapering phenomenon that occurs when the photosensitive composition is patterned.

As the organic solvent in the energy-sensitive composition of the third embodiment, the organic solvents exemplified in the energy-sensitive composition of the first embodiment can be mentioned.
The content of the organic solvent is preferably such that the solids concentration of the energy-sensitive composition of the third embodiment is from 1% by mass to 50% by mass, more preferably from 5% by mass to 30% by mass.
The energy-sensitive composition of the third embodiment may contain the above-mentioned various additives, as in the case of the energy-sensitive composition of the first embodiment, if necessary.

(4) Energy-Sensitive Composition of Fourth Aspect The photosensitive composition of the fourth aspect is a negative-type photosensitive composition containing an epoxy group-containing polycarboxylic acid resin, a photoacid generator, and an organic solvent together with a metal oxide (A).

As the epoxy group-containing polycarboxylic acid resin in the photosensitive composition of the fourth embodiment, for example, a resin obtained by further reacting a polybasic acid anhydride with a reaction product obtained by reacting an epoxy compound having two or more epoxy groups in one molecule with a monocarboxylic acid having one or more alcoholic hydroxyl groups in one molecule can be used.

Epoxy compounds having two or more epoxy groups in one molecule include, for example, the epoxy compounds listed above as the epoxy resin precursors and the epoxy group-containing resins listed above. Among them, novolac-type epoxy resins, bisphenol-type epoxy resins, trisphenolmethane-type epoxy resins, tris(2,3-epoxypropyl)isocyanurate, biphenyl diglycidyl ether, alicyclic epoxy resins, copolymer-type epoxy resins, etc. can be mentioned.

Novolac-type epoxy resins include, for example, epoxy resins obtained by reacting novolacs obtained by reacting phenols such as phenol, cresol, halogenated phenols, and alkylphenols with formaldehyde under an acidic catalyst with epichlorohydrin or methyl epichlorohydrin. Commercially available products include EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1027, EPPN-201, and BREN-S (all manufactured by Nippon Kayaku Co., Ltd.); DEN-431 and DEN-439 (all manufactured by Dow Chemical Co.); N-730, N-770, N-865, N-665, N-673, and VH-4150 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.).

Examples of bisphenol-type epoxy resins include epoxy resins obtained by reacting bisphenols such as bisphenol A, bisphenol F, bisphenol S, and tetrabromobisphenol A with epichlorohydrin or methylepichlorohydrin, and epoxy resins obtained by reacting diglycidyl ethers of bisphenol A or bisphenol F with condensates of the above bisphenols with epichlorohydrin or methylepichlorohydrin. Commercially available products include Epicoat 1004, Epicoat 1002, Epicoat 4002, and Epicoat 4004 (all manufactured by Yuka Shell Epoxy Co., Ltd.).

Examples of trisphenolmethane type epoxy resins include epoxy resins obtained by reacting trisphenolmethane or triscretholmethane with epichlorohydrin or methylepichlorohydrin. Commercially available products include EPPN-501 and EPPN-502 (both manufactured by Nippon Kayaku Co., Ltd.).

Examples of alicyclic epoxy resins include the same alicyclic epoxy compounds as those mentioned above. Commercially available products include CELLOXIDE 2021 manufactured by Daicel Chemical Industries, Ltd.; EPOMIC VG-3101 manufactured by Mitsui Petrochemical Industries, Ltd.; E-1031S manufactured by Yuka Shell Epoxy Co., Ltd.; and EPB-13 and EPB-27 manufactured by Nippon Soda Co., Ltd. Examples of copolymer epoxy resins include CP-50M and CP-50S manufactured by Nippon Oil & Fats Corporation, which are copolymers of glycidyl methacrylate, styrene, and α-methylstyrene, and copolymers of glycidyl methacrylate and cyclohexylmaleimide, etc.

Particularly preferred examples of these epoxy resins having two or more epoxy groups in one molecule include cresol novolac type epoxy resins, phenol novolac type epoxy resins, bisphenol type epoxy resins, trisphenolmethane type epoxy resins, etc. In particular, polycondensates of α-hydroxyphenyl-ω-hydropoly(biphenyldimethylene-hydroxyphenylene) and 1-chloro-2,3-epoxypropane, and α-2,3-epoxypropoxyphenyl-ω-hydropoly{2-(2,3-epoxypropoxy)-benzylidene-2,3-epoxypropoxyphenylene} are preferred.

Examples of monocarboxylic acids having one or more alcoholic hydroxyl groups in one molecule include hydroxymonocarboxylic acids such as dimethylolpropionic acid, dimethylolacetic acid, dimethylolbutyric acid, dimethylolvaleric acid, dimethylolcaproic acid, and hydroxypivalic acid. Among these, monocarboxylic acids having 1 to 5 alcoholic hydroxyl groups in one molecule are preferred.

Examples of polybasic acid anhydrides include succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl-end-methylene tetrahydrophthalic anhydride, trimellitic anhydride, and pyromellitic anhydride.

In the reaction between the epoxy compound and the monocarboxylic acid, the monocarboxylic acid is preferably 0.1 moles or more and 0.7 moles or less, more preferably 0.2 moles or more and 0.5 moles or less, per equivalent of the epoxy group of the epoxy compound. In this reaction, it is preferable to use an organic solvent that does not react with the epoxy compound or the polybasic acid anhydride and does not have a hydroxyl group or a carboxyl group. Furthermore, a catalyst (e.g., triphenylphosphine, benzyldimethylamine, trialkylammonium chloride, triphenylstibine, etc.) can be used to promote the reaction. When a catalyst is used, it is preferable to inactivate the catalyst using an organic peroxide or the like after the reaction is completed, as it is stable and has good storage properties. The amount of the reaction catalyst used is preferably 0.1 mass% or more and 10 mass% or less with respect to the reaction mixture, and the reaction temperature is preferably 60°C or more and 150°C or less. This makes it possible to obtain a reaction product of the epoxy compound and the monocarboxylic acid.

In the reaction of this reactant with a polybasic acid anhydride, it is preferable to react an amount of polybasic acid anhydride such that the acid value of the final epoxy group-containing polycarboxylic acid resin is 50 mgKOH/g or more and 150 mgKOH/g or less. The reaction temperature is preferably 60°C or more and 150°C or less. In this way, an epoxy group-containing polycarboxylic acid resin can be obtained.

These epoxy group-containing polycarboxylic acid resins can be used alone or in combination of two or more.

The content of the epoxy group-containing polycarboxylic acid resin is preferably 30% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 70% by mass or less, based on the solid content of the energy-sensitive composition of the fourth embodiment. By setting the content within the above range, the coating film forming ability can be improved.

Examples of the photoacid generator in the energy-sensitive composition of the fourth embodiment include the photoacid generators exemplified in the photosensitive composition of the second embodiment.
The content of the photoacid generator is preferably 0.5% by mass or more and 30% by mass or less, and more preferably 1% by mass or more and 20% by mass or less, based on the solid content of the energy-sensitive composition of the fourth embodiment. By setting the content within the above range, the curability of the photosensitive composition becomes good.

The energy-sensitive composition of the fourth embodiment may further contain a modifying component for adjusting moisture resistance, heat resistance, adhesion, etc. This modifying component may be cured by itself by heat, ultraviolet light, etc., or may react with the remaining hydroxyl groups or carboxyl groups of the epoxy group-containing polycarboxylic acid resin by heat, ultraviolet light, etc. Specific examples include epoxy compounds having one or more epoxy groups in one molecule, melamine derivatives (e.g., hexamethoxymelamine, hexabutoxylated melamine, condensed hexamethoxymelamine, etc.), bisphenol A compounds (e.g., tetramethylol bisphenol A, etc.), oxazoline compounds, etc.

Epoxy compounds having one or more epoxy groups per molecule include bisphenol A type epoxy resins such as Epicoat 1009 and 1031 (both manufactured by Yuka Shell), Epiclon N-3050 and N-7050 (both manufactured by Dainippon Ink and Chemicals), DER-642U and DER-673MF (both manufactured by Dow Chemical); hydrogenated bisphenol A type epoxy resins such as ST-2004 and ST-2007 (both manufactured by Tohto Kasei Co., Ltd.); Bisphenol A type epoxy resins; bisphenol F type epoxy resins such as YDF-2004 and YDF-2007 (both manufactured by Tohto Kasei Co., Ltd.); brominated bisphenol A type epoxy resins such as SR-BBS, SR-TBA-400 (both manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), YDB-600, and YDB-715 (both manufactured by Tohto Kasei Co., Ltd.); EPPN-201, EOCN-103, EOCN-1020, BREN (all manufactured by Tohto Kasei Co., Ltd.); Novolac type epoxy resins such as Epicron N-880 manufactured by Dainippon Ink &Chemicals; bisphenol A novolac type epoxy resins such as Epicron TSR-601 manufactured by Dainippon Ink & Chemicals and R-1415-1 manufactured by ACS; bisphenol S type epoxy resins such as EBPS-200 manufactured by Nippon Kayaku and Epicron EXA-1514 manufactured by Dainippon Ink &Chemicals; diglycidyl terephthalates such as Plenmer DGT manufactured by Nippon Oil &Fats; triglycidyl isocyanurates such as TEPIC manufactured by Nissan Chemical Industries; bixylenol type epoxy resins such as YX-4000 manufactured by Yuka Shell; bisphenol type epoxy resins such as YL-6056 manufactured by Yuka Shell; alicyclic epoxy resins such as Celloxide 2021 manufactured by Daicel Chemical Industries; and the like.

The content of the modifying component is preferably 50% by mass or less, and more preferably 30% by mass or less, based on the solid content of the energy-sensitive composition of the fourth embodiment.

The energy-sensitive composition of the fourth embodiment may further contain a colorant, similar to the energy-sensitive composition of the first embodiment.

As the organic solvent in the energy-sensitive composition of the fourth embodiment, the organic solvents exemplified in the photosensitive composition of the first embodiment can be mentioned.
The content of the organic solvent is preferably an amount such that the solids concentration of the energy-sensitive composition of the fourth embodiment is 1% by mass or more and 50% by mass or less, and more preferably an amount such that the solids concentration is 5% by mass or more and 30% by mass or less.

(5) Energy-Sensitive Composition of Fifth Aspect The energy-sensitive composition of the fifth aspect is a curable composition containing a metal oxide (A), a curable compound represented by the above formula (b-01) as a base component (B), and a curing agent.
The curable compound is a compound represented by formula (b-01), which has a condensed polycyclic skeleton containing an aromatic ring as the main skeleton and has a polymerizable group.
When the energy-sensitive composition contains a compound containing an aromatic ring such as the compound represented by formula (b-01), the metal oxide (A) may be difficult to disperse well in the energy-sensitive composition.
When poor dispersion such as aggregation of the metal oxide (A) occurs in the energy-sensitive composition, cracks may occur in the cured product. However, when the energy-sensitive composition contains the metal oxide (A) containing the above-mentioned surface-modified metal oxide fine particles together with the compound represented by formula (b-01) as the curable compound, the above-mentioned crack problem is unlikely to occur.

Below, essential or optional components contained in the curable composition as the energy-sensitive composition of the fifth embodiment, other than the curable compound represented by formula (b-01), are described.

The curable compound may contain a cationically polymerizable compound other than the compound represented by the above formula (b-01). The amount of the compound represented by the above formula (a1) in the curable compound is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

The curable compound may contain a cationic polymerizable compound other than the compound represented by formula (b-01), and examples thereof include a vinyl ether compound containing a vinyloxy group, an epoxy compound containing an epoxy group, an episulfide compound containing an episulfide group, and a radically polymerizable compound having an unsaturated double bond capable of radical polymerization. In addition, for the purpose of adjusting the refractive index of the cured product, a compound in which both W ⁰¹ and W ⁰² of the compound represented by formula (b-01) have a hydrogen atom as R ⁰³ may be combined. In the formula (b-02) of the compound, rings Z ⁰¹ , X ⁰¹ , R ⁰¹ , R ⁰² , and M are the same as those of the compound represented by formula (b-01).
The vinyl ether compound, the epoxy compound, the episulfide compound, and the radical polymerizable compound will be described below.

(Vinyl ether compounds)
The vinyl ether compound that can be used together with the compound represented by formula (b-01) is not particularly limited as long as it has a vinyloxy group and is cationic polymerizable.
The vinyl ether compound used in combination with the compound represented by formula (b-01) may or may not contain an aromatic group.
From the viewpoint of transparency of the cured product, the vinyl ether compound used in combination with the compound represented by formula (b-01) is preferably an aliphatic vinyl ether compound containing no aromatic group.
From the viewpoint of obtaining a cured product with good thermal decomposition resistance, the vinyl ether compound used in combination with the compound represented by formula (b-01) is preferably a compound having a vinyloxy group bonded to an aromatic group.

Specific preferred examples of vinyl ether compounds that can be used together with the compound represented by formula (b-01) include ethyl vinyl ether, isobutyl vinyl ether, hydroxybutyl vinyl ether, butanediol divinyl ether, cyclohexyl vinyl ether, N-butyl vinyl ether, tert-butyl vinyl ether, triethylene glycol divinyl ether octadecyl vinyl ether, cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, and cyclohexanedimethanol monovinyl ether vinyl phenyl ether. aliphatic vinyl ether compounds such as 4-vinyloxytoluene, 3-vinyloxytoluene, 2-vinyloxytoluene, 1-vinyloxy-4-chlorobenzene, 1-vinyloxy-3-chlorobenzene, 1-vinyloxy-2-chlorobenzene, 1-vinyloxy-2,3-dimethylbenzene, 1-vinyloxy-2,4-dimethylbenzene, 1-vinyloxy-2,5-dimethylbenzene, 1-vinyloxy-2,6-dimethylbenzene, 1-vinyloxy-3,4-dimethylbenzene, 1-vinyloxy-3,5-dimethylbenzene, 1-vinyloxynaphthalene, 2-vinyloxynaphthalene, 2-vinyloxy aromatic monovinyl ether compounds such as vinyloxyfluorene, 3-vinyloxyfluorene, 4-vinyloxy-1,1'-biphenyl, 3-vinyloxy-1,1'-biphenyl, 2-vinyloxy-1,1'-biphenyl, 6-vinyloxytetralin, and 5-vinyloxytetralin; 1,4-divinyloxybenzene, 1,3-divinyloxybenzene, 1,2-divinyloxybenzene, 1,4-divinyloxynaphthalene, 1,3-divinyloxynaphthalene, 1,2-divinyloxynaphthalene, 1,5-divinyloxynaphthalene, 1,6-divinyloxynaphthalene, 1,7-divinyloxy Examples of the aromatic divinyl ether compounds include naphthalene, 1,8-divinyloxynaphthalene, 2,3-divinyloxynaphthalene, 2,6-divinyloxynaphthalene, 2,7-divinyloxynaphthalene, 1,2-divinyloxyfluorene, 3,4-divinyloxyfluorene, 2,7-divinyloxyfluorene, 4,4'-divinyloxybiphenyl, 3,3'-divinyloxybiphenyl, 2,2'-divinyloxybiphenyl, 3,4'-divinyloxybiphenyl, 2,3'-divinyloxybiphenyl, 2,4'-divinyloxybiphenyl, and bisphenol A divinyl ether.
These vinyl ether compounds may be used in combination of two or more kinds.

(Epoxy Compound)
Examples of the epoxy compound that can be used together with the compound represented by formula (b-01) include the same epoxy compounds as the epoxy resin precursor as the thermosetting material described above for the base component (B).

(Episulfide Compounds)
The type of episulfide compound is not particularly limited as long as it does not impede the object of the present invention. Preferred episulfide compounds include the above-mentioned epoxy compounds in which the oxygen atom in the epoxy group is replaced with a sulfur atom.

(Radically polymerizable compound)
As the radical polymerizable compound, a compound having an ethylenically unsaturated group can be used. The compound having an ethylenically unsaturated group includes a monofunctional compound and a polyfunctional compound.

Monofunctional compounds include (meth)acrylamide, methylol (meth)acrylamide, methoxymethyl (meth)acrylamide, ethoxymethyl (meth)acrylamide, propoxymethyl (meth)acrylamide, butoxymethoxymethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, (meth)acrylic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, crotonic acid, 2-acrylamido-2-methylpropanesulfonic acid, tert-butylacrylamidosulfonic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl acrylate, ethyl acrylate, butyl ... Examples of the monofunctional compounds include xyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-(meth)acryloyloxy-2-hydroxypropyl phthalate, glycerin mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, and half (meth)acrylate of phthalic acid derivative. These monofunctional compounds can be used alone or in combination of two or more.

On the other hand, examples of polyfunctional compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxypolyethoxyphenyl)propane, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, ethylene glycol diglycidyl ether di(meth)acrylate, diethylene glycol diglycidyl ether di(meth)acrylate, phthalic acid diglycidyl ester di(meth)acrylate, glycerin triacrylate, glycerin polyglycerin Examples of such polyfunctional compounds include lysidyl ether poly(meth)acrylate, urethane (meth)acrylate (i.e., a reaction product of tolylene diisocyanate, trimethylhexamethylene diisocyanate, or hexamethylene diisocyanate, etc., with 2-hydroxyethyl (meth)acrylate), methylene bis(meth)acrylamide, (meth)acrylamide methylene ether, and a condensation product of a polyhydric alcohol and N-methylol (meth)acrylamide, as well as triacrylformal. These polyfunctional compounds can be used alone or in combination of two or more.

Among these compounds having an ethylenically unsaturated group, polyfunctional compounds having three or more functional groups are preferred, polyfunctional compounds having four or more functional groups are more preferred, and polyfunctional compounds having five or more functional groups are even more preferred, because they tend to increase the adhesion of the cured product to the substrate and the strength of the curable composition after curing.

The content of the curable compound in the energy-sensitive composition of the fifth embodiment is not particularly limited as long as it does not impede the object of the present invention. The content of the curable compound in the energy-sensitive composition of the fifth embodiment is preferably 3% by mass or more and 95% by mass or less, more preferably 5% by mass or more and 90% by mass or less, even more preferably 10% by mass or more and 85% by mass or less, and particularly preferably 20% by mass or more and 80% by mass or less, based on the total mass of the other components excluding the solvent.

The content of the metal oxide (A) in the energy-sensitive composition of the fifth embodiment is not particularly limited as long as it does not impede the object of the present invention. In order to easily achieve both a high refractive index and good flexibility in the cured product, the mass ratio of the curable compound to the metal oxide (A) is typically preferably 1:99 to 95:5, more preferably 5:95 to 90:10, even more preferably 10:90 to 85:15, and particularly preferably 30:70 to 80:20. In addition, the content is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 93% by mass or less, even more preferably 15% by mass or more and 90% by mass or less, and particularly preferably 20% by mass or more and 80% by mass or less, based on the mass of the curable composition excluding the solvent.

(Hardening agent)
The curable composition contains a curing agent from the viewpoint of promoting curing. The curing agents may be used alone or in combination.
From the viewpoint that the curable composition is of a cationic curing type or an anionic curing type, the curing agent is preferably a cationic polymerization initiator or an anionic polymerization initiator, and more preferably a cationic polymerization initiator.

Onium salt (B01)
Preferred cationic polymerization initiators include gallium-containing onium salts having an anion moiety represented by the following formula (bi) and boron-containing onium salts having an anion moiety represented by the following formula (bii).
A gallium-containing onium salt having an anion moiety represented by the following formula (bi) and a boron-containing onium salt having an anion moiety represented by the following formula (bii) are collectively referred to as "onium salt (B01)".
From the viewpoint of curability, the cationic polymerization initiator also preferably contains both a gallium-containing onium salt having an anion moiety represented by the following formula (ai) and a boron-containing onium salt having an anion moiety represented by the following formula (aii).

（式（ｂｉ）中、Ｒ^ｂ０１、Ｒ^ｂ０２、Ｒ^ｂ０３及びＲ^ｂ０４は、それぞれ独立に、置換基を有していてもよい炭化水素基、又は置換基を有していてもよい複素環基であり、Ｒ^ｂ０１、Ｒ^ｂ０２、Ｒ^ｂ０３、及びＲ^ｂ０４のうちの少なくとも１つが置換基を有してもよい芳香族炭化水素基である。）

（式（ｂｉｉ）中、Ｒ^ｂ０５、Ｒ^ｂ０６、Ｒ^ｂ０７、及びＲ^ｂ０８は、それぞれ独立に、置換基を有していてもよい炭化水素基、又は置換基を有していてもよい複素環基であり、Ｒ^ｂ０５、Ｒ^ｂ０６、Ｒ^ｂ０７、及びＲ^ｂ０８のうちの少なくとも１つが置換基を有していてもよい芳香族炭化水素基である。）

(In formula (bi), R ^b01 , R ^b02 , R ^b03 and R ^b04 each independently represent a hydrocarbon group which may have a substituent, or a heterocyclic group which may have a substituent, and at least one of R ^b01 , R ^b02 , R ^b03 and R ^b04 is an aromatic hydrocarbon group which may have a substituent.)

(In formula (bii), R ^b05 , R ^b06 , R ^b07 , and R ^b08 each independently represent a hydrocarbon group which may have a substituent, or a heterocyclic group which may have a substituent, and at least one of R ^b05 , R ^b06 , R ^b07 , and R ^b08 is an aromatic hydrocarbon group which may have a substituent.)

In the gallium-containing onium salt having an anion moiety represented by formula (bi) and the boron-containing onium salt having an anion moiety represented by formula (bii), the counter cation (cation moiety) for the anion represented by formula (bi) or formula (bii) is not particularly limited as long as the curable composition is cured well.
(R ^b09 ) _T+1 -R ^b010+ ...(biv)
(In formula (biv), R ^b09 is a monovalent organic group. R ^b010 is an element in Group 15 to 17 of the Periodic Table of the Elements (IUPAC notation) and has a valence of T. T is an integer of 1 to 3. Multiple R ^b09s may be the same or different, and multiple R ^b09s may be bonded to form a ring together with R ^b010 .)

The number of carbon atoms in the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 in formula (bi) is not particularly limited, but is preferably 1 or more and 50 or less, more preferably 1 or more and 30 or less, and particularly preferably 1 or more and 20 or less.
Specific examples of the hydrocarbon group as R ^b01 to R ^b04 include a linear or branched alkyl group, a linear or branched alkenyl group, a linear or branched alkynyl group, an aromatic hydrocarbon group, an alicyclic hydrocarbon group, and an aralkyl group.
As described above, at least one of R ^b01 to R ^b04 is an aromatic group which may have a substituent, it is more preferable that three or more of R ^b01 to R ^b04 are aromatic groups which may have a substituent, and it is particularly preferable that all of R ^b01 to R ^b04 are aromatic groups which may have a substituent.

Examples of substituents that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have include a halogenated alkyl group having from 1 to 18 carbon atoms, a halogenated aliphatic cyclic group having from 3 to 18 carbon atoms, a nitro group, a hydroxyl group, a cyano group, an alkoxy group having from 1 to 18 carbon atoms, an aryloxy group having from 6 to 14 carbon atoms, an aliphatic acyl group having from 2 to 19 carbon atoms, an aromatic acyl group having from 7 to 15 carbon atoms, an aliphatic acyloxy group having from 2 to 19 carbon atoms, an aromatic acyloxy group having from 7 to 15 carbon atoms, an alkylthio group having from 1 to 18 carbon atoms, an arylthio group having from 6 to 14 carbon atoms, an amino group in which one or two hydrogen atoms bonded to the nitrogen atom may be substituted with a hydrocarbon group having from 1 to 18 carbon atoms, and a halogen atom.
When the hydrocarbon groups represented by R ^b01 to R ^b04 are aromatic hydrocarbon groups, the aromatic hydrocarbon groups may be substituted with one or more substituents selected from the group consisting of alkyl groups having from 1 to 18 carbon atoms, alkenyl groups having from 2 to 18 carbon atoms, and alkynyl groups having from 2 to 18 carbon atoms.

When the hydrocarbon group represented by R ^b01 to R ^b04 has a substituent, the number of the substituent is not particularly limited and may be 1 or a plurality of more than 2. When the number of the substituents is a plurality, the plurality of substituents may be the same or different.

When R ^b01 to R ^b04 are each an alkyl group, specific preferred examples thereof include straight-chain alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-icosyl group; and branched-chain alkyl groups such as an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, an isohexyl group, a 2-ethylhexyl group, and a 1,1,3,3-tetramethylbutyl group.

When R ^b01 to R ^b04 are an alkenyl group or an alkynyl group, preferred examples include alkenyl groups and alkynyl groups corresponding to the above-mentioned groups preferred as the alkyl group.

When R ^b01 to R ^b04 are aromatic hydrocarbon groups, suitable examples thereof include a phenyl group, an α-naphthyl group, a β-naphthyl group, a biphenyl-4-yl group, a biphenyl-3-yl group, a biphenyl-2-yl group, an anthryl group, and a phenanthryl group.

When R ^b01 to R ^b04 are each an alicyclic hydrocarbon group, suitable examples thereof include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopentyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl group; and bridged aliphatic cyclic hydrocarbon groups such as a norbornyl group, an adamantyl group, a tricyclodecyl group, and a pinanyl group.

When R ^b01 to R ^b04 are aralkyl groups, preferred examples thereof include a benzyl group, a phenethyl group, an α-naphthylmethyl group, a β-naphthylmethyl group, an α-naphthylethyl group, and a β-naphthylethyl group.

Preferred examples of heterocyclic groups each of R ^b01 to R ^b04 include a thienyl group, a furanyl group, a selenophenyl group, a pyranyl group, a pyrrolyl group, an oxazolyl group, a thiazolyl group, a pyridyl group, a pyrimidyl group, a pyrazinyl group, an indolyl group, a benzofuranyl group, a benzothienyl group, a quinolyl group, an isoquinolyl group, a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, an acridinyl group, a phenothiazinyl group, a phenazinyl group, a xanthenyl group, a thianthrenyl group, a phenoxazinyl group, a phenoxathiinyl group, a chromanyl group, an isochromanyl group, a dibenzothienyl group, a xanthonyl group, a thioxanthonyl group, and a dibenzofuranyl group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is a halogenated alkyl group, preferred examples of the halogenated alkyl group include linear halogenated alkyl groups such as a trifluoromethyl group, a trichloromethyl group, a pentafluoroethyl group, a 2,2,2-trichloroethyl group, a 2,2,2-trifluoroethyl group, a 1,1-difluoroethyl group, a heptafluoro-n-propyl group, a 1,1-difluoro-n-propyl group, a 3,3,3-trifluoro-n-propyl group, a nonafluoro-n-butyl group, a 3,3,4,4,4-pentafluoro-n-butyl group, a perfluoro-n-pentyl group, and a perfluoro-n-octyl group; and branched halogenated alkyl groups such as a hexafluoroisopropyl group, a hexachloroisopropyl group, a hexafluoroisobutyl group, and a nonafluoro-tert-butyl group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is a halogenated aliphatic cyclic group, preferred examples of the halogenated aliphatic cyclic group include a pentafluorocyclopropyl group, a nonafluorocyclobutyl group, a perfluorocyclopentyl group, a perfluorocyclohexyl group, and a perfluoroadamantyl group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an alkoxy group, preferred examples of the alkoxy group include a methoxy group, an ethoxy group, a n-propyloxy group, a n-butyloxy group, a n-pentyloxy group, a n-hexyloxy group, a n-octyloxy group, a n-nonyloxy group, a n-decyloxy group, a n-undecyloxy group, a n-dodecyloxy group, a n-tridecyloxy group, a n-tetradecyloxy group, a n-pentadecyloxy group, linear alkoxy groups such as an oxy group, an n-hexadecyloxy group, an n-heptadecyloxy group, and an n-octadecyloxy group; and branched alkoxy groups such as an isopropyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an isopentyloxy group, a neopentyloxy group, a tert-pentyloxy group, an isohexyloxy group, a 2-ethylhexyloxy group, and a 1,1,3,3-tetramethylbutyloxy group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an aryloxy group, preferred examples of the aryloxy group include a phenoxy group, an α-naphthyloxy group, a β-naphthyloxy group, a biphenyl-4-yloxy group, a biphenyl-3-yloxy group, a biphenyl-2-yloxy group, an anthryloxy group, and a phenanthryloxy group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an aliphatic acyl group, preferred examples of the aliphatic acyl group include an acetyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, and an octanoyl group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an aromatic acyl group, preferred examples of the aromatic acyl group include a benzoyl group, an α-naphthoyl group, a β-naphthoyl group, a biphenyl-4-ylcarbonyl group, a biphenyl-3-ylcarbonyl group, a biphenyl-2-ylcarbonyl group, an anthrylcarbonyl group, and a phenanthrylcarbonyl group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an aliphatic acyloxy group, preferred examples of the aliphatic acyloxy group include an acetyloxy group, a propanoyloxy group, a butanoyloxy group, a pentanoyloxy group, a hexanoyloxy group, a heptanoyloxy group, and an octanoyloxy group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an aromatic acyloxy group, preferred examples of the aromatic acyloxy group include a benzoyloxy group, an α-naphthoyloxy group, a β-naphthoyloxy group, a biphenyl-4-ylcarbonyloxy group, a biphenyl-3-ylcarbonyloxy group, a biphenyl-2-ylcarbonyloxy group, an anthrylcarbonyloxy group, and a phenanthrylcarbonyloxy group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is an alkylthio group or an arylthio group, preferred examples of the alkylthio group or arylthio group include groups in which the oxygen atom in the group suitable for the above-mentioned alkoxy group or aryloxy group is substituted with a sulfur atom.

When the substituent that the hydrocarbon group or heterocyclic group as R ^b01 to R ^b04 may have is an amino group optionally substituted with a hydrocarbon group, suitable examples of the amino group optionally substituted with a hydrocarbon group include an amino group, a methylamino group, an ethylamino group, an n-propylamino group, a dimethylamino group, a diethylamino group, a methylethylamino group, a di-n-propylamino group, and a piperidino group.

When the substituent that the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 may have is a halogen atom, suitable examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Among the substituents which the hydrocarbon groups or heterocyclic groups represented by R ^b01 to R ^b04 explained above may have, preferred are halogenated alkyl groups having from 1 to 8 carbon atoms, halogen atoms, nitro groups, and cyano groups, and more preferred are fluorinated alkyl groups having from 1 to 8 carbon atoms, in that they have high activity as a cationic polymerization initiator for a gallium onium salt having an anion moiety represented by formula (bi).

Examples of R ^b05 to R ^b08 in formula (bii) include the same groups as those described above for R ^b01 to R ^b04 in formula (bi).

R ^b09 in formula (biv) which is a cation moiety is an organic group bonded to R ^b010 . When there are a plurality of R ^b09 , the plurality of R ^b09 may be the same or different. Examples of R ^b09 include an aromatic hydrocarbon group having 6 to 14 carbon atoms which may have a substituent, an alkyl group having 1 to 18 carbon atoms which may have a substituent, an alkenyl group having 2 to 18 carbon atoms which may have a substituent, and an alkynyl group having 2 to 18 carbon atoms which may have a substituent. In the case of a photosensitive curing agent having a cation represented by formula (biv) as a cation moiety, R ^b09 is preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, and an alkynyl group having 2 to 18 carbon atoms.
Examples of the substituent that the aromatic hydrocarbon group, aralkyl group, alkyl group, alkenyl group, and alkynyl group as R ^b09 may have include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms, a nitro group, a hydroxyl group, a cyano group, an alkoxy group having 1 to 18 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aliphatic acyl group having 2 to 19 carbon atoms, an aromatic acyl group having 7 to 15 carbon atoms, an aliphatic acyloxy group having 2 to 19 carbon atoms, an aromatic acyloxy group having 7 to 15 carbon atoms, an alkylthio group having 1 to 18 carbon atoms, an arylthio group having 6 to 14 carbon atoms, an amino group in which one or two hydrogen atoms bonded to the nitrogen atom may be substituted with a hydrocarbon group having 1 to 18 carbon atoms, and a halogen atom.
Suitable examples of these substituents are the same as the suitable examples of the substituents which the hydrocarbon group or heterocyclic group represented by R ^b01 to R ^b04 in formula (bi) may have.

In formula (biv), when a plurality of R ^b09 are present, the plurality of R ^b09 may form a ring together with R ^b010 . The ring formed by the plurality of R ^b09 and R ^b010 may contain one or more bonds selected from the group consisting of -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, and -CONH- in the structure therebetween.

In formula (biv), R ^b010 is an element in Groups 15 to 17 of the Periodic Table of the Elements (IUPAC notation) having a valence of T. T is an integer of 1 to 3. The elements in Groups 15 to 17 of the Periodic Table of the Elements (IUPAC notation) as R ^b010 are elements that can exist stably under the production conditions and storage conditions of the curable composition, and under the formation conditions of the metal oxide-containing film.
R ^b010 bonds with the organic group R ^b09 to form an onium ion [R ^b010+ ]. Among the elements of Groups 15 to 17 of the Periodic Table of Elements (IUPAC notation), preferred elements for R ^a10 are O (oxygen), N (nitrogen), P (phosphorus), S (sulfur), or I (iodine). Corresponding onium ions include oxonium ions, ammonium ions, phosphonium ions, sulfonium ions, and iodonium ions. Among these, ammonium ions, phosphonium ions, sulfonium ions, and iodonium ions are preferred because they are stable and easy to handle, and sulfonium ions and iodonium ions are more preferred because they have excellent cationic polymerization performance and crosslinking reaction performance.

Specific examples of oxonium ions include oxoniums such as trimethyloxonium, diethylmethyloxonium, triethyloxonium, and tetramethylenemethyloxonium; pyriliniums such as 4-methylpyrilinium, 2,4,6-trimethylpyrilinium, 2,6-di-tert-butylpyrilinium, and 2,6-diphenylpyrilinium; chromeniums such as 2,4-dimethylchromenium and 1,3-dimethylisochromenium, and isochromenium.

Specific examples of ammonium ions include tetraalkylammoniums such as tetramethylammonium, ethyltrimethylammonium, diethyldimethylammonium, triethylmethylammonium, and tetraethylammonium; pyrrolidiniums such as N,N-dimethylpyrrolidinium, N-ethyl-N-methylpyrrolidinium, and N,N-diethylpyrrolidinium; imidazoliniums such as N,N'-dimethylimidazolinium, N,N'-diethylimidazolinium, N-ethyl-N'-methylimidazolinium, 1,3,4-trimethylimidazolinium, and 1,2,3,4-tetramethylimidazolinium; N,N'-dimethyltetrahydro These include tetrahydropyrimidiniums such as pyrimidinium; morpholiniums such as N,N'-dimethylmorpholinium; piperidiniums such as N,N'-diethylpiperidinium; pyridiniums such as N-methylpyridinium, N-benzylpyridinium, and N-phenacylpyridinium; imidazoliums such as N,N'-dimethylimidazolium; quinoliums such as N-methylquinolium, N-benzylquinolium, and N-phenacylquinolium; isoquinoliums such as N-methylisoquinolium; thiazoniums such as benzylbenzothiazonium and phenacylbenzothiazonium; and acridiums such as benzylacridium and phenacylacridium.

Specific examples of phosphonium ions include tetraarylphosphoniums such as tetraphenylphosphonium, tetra-p-tolylphosphonium, tetrakis(2-methoxyphenyl)phosphonium, tetrakis(3-methoxyphenyl)phosphonium, and tetrakis(4-methoxyphenyl)phosphonium; triarylphosphoniums such as triphenylbenzylphosphonium, triphenylphenacylphosphonium, triphenylmethylphosphonium, and triphenylbutylphosphonium; and tetraalkylphosphoniums such as triethylbenzylphosphonium, tributylbenzylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, tetrahexylphosphonium, triethylphenacylphosphonium, and tributylphenacylphosphonium.

Specific examples of sulfonium ions include triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris(4-methoxyphenyl)sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, tris(4-fluorophenyl)sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris(4-hydroxyphenyl)sulfonium, 4-(phenylthio)phenyldiphenylsulfonium, and 4-(p-tolylthio)phenyl. nyldi-p-tolylsulfonium, 4-(4-methoxyphenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(phenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(phenylthio)phenylbis(4-methoxyphenyl)sulfonium, 4-(phenylthio)phenyldi-p-tolylsulfonium, [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium, [4-(2-thioxanthonylthio)phenyl]diphenylsulfonium, bis[4-(di 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, ... 2-chlorophenylthio)phenyldiphenylsulfonium, 4-(4-benzoylphenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl)sulfonio]thioxanthone , 2-[(diphenyl)sulfonio]thioxanthone, 4-(9-oxo-9H-thioxanthen-2-yl)thiophenyl-9-oxo-9H-thioxanthen-2-ylphenylsulfonium, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-[4-(4-tert-butylbenzoyl)phenylthio]phenyldiphenylsulfonium, 4-[4-(benzoylphenylthio)]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio) ]triarylsulfonium such as phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thiaanthrenenium, 5-phenylthiaanthrenenium, 5-trilthiaanthrenenium, 5-(4-ethoxyphenyl)thiaanthrenenium, and 5-(2,4,6-trimethylphenyl)thiaanthrenenium; diarylsulfonium such as diphenylphenacylsulfonium, diphenyl4-nitrophenacylsulfonium, diphenylbenzylsulfonium, and diphenylmethylsulfonium; phenylmethylbenzyl monoarylsulfonium such as arylsulfonium, 4-hydroxyphenylmethylbenzylsulfonium, 4-methoxyphenylmethylbenzylsulfonium, 4-acetocarbonyloxyphenylmethylbenzylsulfonium, 4-hydroxyphenyl(2-naphthylmethyl)methylsulfonium, 2-naphthylmethylbenzylsulfonium, 2-naphthylmethyl(1-ethoxycarbonyl)ethylsulfonium, phenylmethylphenacylsulfonium, 4-hydroxyphenylmethylphenacylsulfonium, 4-methoxyphenylmethylphenacylsulfonium, 4-acetocarbonyloxyphenylmethylphenacylsulfonium, 2-naphthylmethylphenacylsulfonium, 2-naphthyloctadecylphenacylsulfonium, and 9-anthracenylmethylphenacylsulfonium; trialkylsulfonium such as dimethylphenacylsulfonium, phenacylterahydrothiophenium, dimethylbenzylsulfonium, benzyltetrahydrothiophenium, and octadecylmethylphenacylsulfonium.

It is also preferable that the onium salt (B01) contains a sulfonium salt having an anion portion which is an anion represented by the above formula (bi) or formula (bii) and a cation portion which is a sulfonium ion represented by the formula (c1) described below.

Specific examples of iodonium ions include diphenyliodonium, di-p-tolyliodonium, bis(4-dodecylphenyl)iodonium, bis(4-methoxyphenyl)iodonium, (4-octyloxyphenyl)phenyliodonium, bis(4-decyloxy)phenyliodonium, 4-(2-hydroxytetradecyloxy)phenylphenyliodonium, 4-isopropylphenyl(p-tolyl)iodonium, and 4-isobutylphenyl(p-tolyl)iodonium.

Preferable specific examples of the anion represented by formula (b0i) are as follows:
tetrakis(4-nonafluorobiphenyl)gallium anion,
tetrakis(1-heptafluoronaphthyl)gallium anion,
tetrakis(pentafluorophenyl)gallium anion,
tetrakis(3,4,5-trifluorophenyl)gallium anion,
tetrakis(2-nonaphenylbiphenyl)gallium anion,
tetrakis(2-heptafluoronaphthyl)gallium anion,
tetrakis(7-nonafluoroanthryl)gallium anion,
tetrakis(4'-(methoxy)octafluorobiphenyl)gallium anion,
tetrakis(2,4,6-tris(trifluoromethyl)phenyl)gallium anion,
tetrakis(3,5-bis(trifluoromethyl)phenyl)gallium anion,
tetrakis(2,3-bis(pentafluoroethyl)naphthyl)gallium anion,
tetrakis(2-isopropoxy-hexafluoronaphthyl)gallium anion,
tetrakis(9,10-bis(heptafluoropropyl)heptafluoroanthryl)gallium anion,
tetrakis(9-nonafluorophenanthryl)gallium anion,
tetrakis(4-[tri(isopropyl)silyl]-tetrafluorophenyl)gallium anion,
tetrakis(9,10-bis(p-tolyl)-heptafluorophenanthryl)gallium anion,
tetrakis(4-[dimethyl(tert-butyl)silyl]-tetrafluorophenyl)gallium anion,
Examples of the anion include monophenyltris(pentafluorophenyl)gallium anion and monoperfluorobutyltris(pentafluorophenyl)gallium anion, and more preferably, the following anions are included.

Preferred specific examples of the anion moiety represented by formula (bii) include
tetrakis(4-nonafluorobiphenyl)boron anion,
tetrakis(1-heptafluoronaphthyl)boron anion,
tetrakis(pentafluorophenyl)boron anion,
tetrakis(3,4,5-trifluorophenyl)boron anion,
tetrakis(2-nonaphenylbiphenyl)boron anion,
tetrakis(2-heptafluoronaphthyl)boron anion,
tetrakis(7-nonafluoroanthryl)boron anion,
tetrakis(4'-(methoxy)octafluorobiphenyl)boron anion,
tetrakis(2,4,6-tris(trifluoromethyl)phenyl)boron anion,
tetrakis(3,5-bis(trifluoromethyl)phenyl)boron anion,
tetrakis(2,3-bis(pentafluoroethyl)naphthyl)boron anion,
tetrakis(2-isopropoxy-hexafluoronaphthyl)boron anion,
tetrakis(9,10-bis(heptafluoropropyl)heptafluoroanthryl)boron anion,
tetrakis(9-nonafluorophenanthryl)boron anion,
tetrakis(4-[tri(isopropyl)silyl]-tetrafluorophenyl)boron anion,
tetrakis(9,10-bis(p-tolyl)-heptafluorophenanthryl)boron anion,
tetrakis(4-[dimethyl(tert-butyl)silyl]-tetrafluorophenyl)boron anion,
Examples of the anion include monophenyltris(pentafluorophenyl)boron anion and monoperfluorobutyltris(pentafluorophenyl)boron anion, and more preferably, the following anions are included.

Preferable specific examples of the cation moiety represented by formula (biv) described above include:
4-isopropylphenyl(p-tolyl)iodonium,
Iodonium ions such as 4-isobutylphenyl(p-tolyl)iodonium;
[4-(2-thioxanthonylthio)phenyl]diphenylsulfonium,
2-[(di-p-tolyl)sulfonio]thioxanthone,
2-[(diphenyl)sulfonio]thioxanthone,
Thioxanthone skeleton-containing sulfonium ions such as 4-(9-oxo-9H-thioxanthen-2-yl)thiophenyl-9-oxo-9H-thioxanthen-2-ylphenylsulfonium;
A cationic moiety represented by formula (biii) described below;
A cation moiety represented by formula (c01) described later;
Other examples include the sulfonium ions shown below.

As described above, an embodiment in which the cationic moiety has the cationic moiety represented by the following formula (biii) is also preferred. When the onium salt as the cationic polymerization initiator has the cationic moiety represented by formula (biii), the onium salt can function as a heat-sensitive curing agent.

（式（ｂｉｉｉ）中、Ｒ^Ｂ０１は、１価の有機基であり、Ｄ^Ｂは、元素周期律表（ＩＵＰＡＣ表記法）の１５族～１７族で原子価がｕの元素であり、Ｒ^Ｂ０２は、置換基を有していてもよいアルキル基又は置換基を有していてもよいアラルキル基である。ただし、Ｒ^Ｂ０２が置換基を有していてもよいアルキル基の場合、Ｒ^Ｂ０１の少なくとも１つは置換基を有していてもよいアルキル基である。ｕは１以上３以下の整数であり、複数のＲ^Ｂ０１は同一でも異なっていてもよく、複数のＲ^Ｂ０１が結合してＤ^Ｂとともに環を形成していてもよい。）

(In formula (biii), R ^B01 is a monovalent organic group, D ^B is an element in Group 15 to 17 of the Periodic Table of the Elements (IUPAC notation) with a valence of u, and R ^B02 is an alkyl group which may have a substituent or an aralkyl group which may have a substituent. However, when R ^B02 is an alkyl group which may have a substituent, at least one of R ^B01 is an alkyl group which may have a substituent. u is an integer of 1 to 3, and multiple R ^B01 may be the same or different, and multiple R ^B01 may be bonded to form a ring together with D ^B. )

D 3 ^B in formula (biii) is an element in Groups 15 to 17 of the Periodic Table of the Elements (IUPAC notation) with a valence of u. D 3 ^B is the same as R ^b010 in formula (biv).
D forms an onium ion by bonding with an organic group R ^B01 and a benzyl group which may be substituted with R ^B02 . Among the elements of groups 15 to 17 of the periodic table of elements (IUPAC notation), preferred are S (sulfur), N (nitrogen), I (iodine) and P (phosphorus). Corresponding onium ions include sulfonium ions, ammonium ions, iodonium ions and phosphonium ions, which are preferred because they are stable and easy to handle. In terms of excellent cationic polymerization performance and crosslinking reaction performance, sulfonium ions and iodonium ions are more preferred.

In formula (biii), R ^B01 represents an organic group bonded to D ^B , and when a plurality of R ^B01 are present, the plurality of R ^B01 may be the same or different. Examples of R ^B01 include aromatic hydrocarbon groups having from 6 to 14 carbon atoms, alkyl groups having from 1 to 18 carbon atoms, alkenyl groups having from 2 to 18 carbon atoms, and alkynyl groups having from 2 to 18 carbon atoms.

Examples of the aromatic hydrocarbon group, alkyl group, alkenyl group, and alkynyl group represented by R ^B01 include the same as those described above for R ^b09 in formula (biv). When R ^B01 is an aromatic hydrocarbon group, it may have a substituent, and examples of the substituent include a hydroxyl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted silyl group, an optionally substituted amino group, and a halogen atom.

In addition, in formula (biii), when a plurality of R ^B01 are present, the plurality of R ^B01 may form a ring together with D ^B. The ring formed by the plurality of R ^B01 and D ^B may contain, in the intervening structure, at least one bond selected from the group consisting of -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, and -CONH-.

In formula (biii), specific examples of the alkyl group as R ^B02 include linear alkyl groups having from 1 to 18 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-octyl group, an n-decyl group, an n-dodecyl group, an n-tetradecyl group, an n-hexadecyl group, and an n-octadecyl group, branched alkyl groups having from 3 to 18 carbon atoms, such as an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, an isohexyl group, and an isooctadecyl group, and cycloalkyl groups having from 3 to 18 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a 4-decylcyclohexyl group. In formula (biii), when R ^B02 is an alkyl group which may have a substituent, at least one of R ^B01 is an alkyl group which may have a substituent.

In formula (biii), specific examples of the aralkyl group represented by R ^B02 include alkyl groups having 1 to 4 carbon atoms substituted with an aryl group having 6 to 10 carbon atoms, such as a benzyl group, a 1-naphthylmethyl group, and a 2-naphthylmethyl group.

In formula (biii), a specific example of the aralkyl group having a substituent as R ^B02 includes an alkyl group having 1 to 4 carbon atoms substituted with an aryl group having 6 to 10 carbon atoms, which may have a substituent, such as a 2-methylbenzyl group.

In formula (biii), R ^B02 is preferably an aralkyl group which may have a substituent, and more preferably a cation moiety represented by the following formula (biii-1).

（式（ｂｉｉｉ－１）中、Ｒ^Ｂ０１、Ｄ^Ｂ、ｕは、前記式（ｂｉｉｉ）と同様である。Ｒ^Ｂ０３は、１価の有機基であり、ｖは０以上５以下の整数であり、複数のＲ^Ｂ０３は同一でも異なっていてもよい。）

(In formula (biii-1), R ^B01 , D ^B , and u are the same as those in formula (biii). R ^B03 is a monovalent organic group, v is an integer of 0 or more and 5 or less, and multiple R ^B03s may be the same or different.)

In formula (biii-1), the monovalent organic group represented by R ^B03 is preferably an alkyl group, and examples thereof include the same alkyl groups as those exemplified for R ^B02 in formula (biii).

Specific examples of the cation moiety represented by formula (biii) or formula (biii-1) are as follows: In the following specific examples, D' is an S atom or a Se atom, and preferably an S atom.

The counter anion of the cationic moiety represented by formula (biii) or formula (biii-1) may be the same as the counter anion of the cationic moiety represented by formula (c01) described below, but is preferably the anionic moiety represented by formula (bi) or the anionic moiety represented by formula (bii), and more preferably the anionic moiety represented by formula (bi).

As the onium salt (B01), a salt consisting of the above anion shown as a specific preferred example of the anion represented by formula (bi) or formula (bII) and the above cation shown as a specific preferred example of the counter cation represented by formula (biv) is preferred. Two or more of the specific preferred examples of the counter cation represented by formula (b0iv) may be combined.

The content of the onium salt (B01) is preferably 10% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass, based on the total amount of the onium salt (B01) and other cationic polymerization initiators (B02) described later.
By using the cationic polymerization initiator in an amount within this range, it is easy to form a metal oxide-containing film that has excellent refractive index and yellowing resistance, as well as good heat resistance (resistance to thermal decomposition) and adhesion to the substrate.

- A cationic polymerization initiator (B02) different from the onium salt (B01)
The cationic polymerization initiator may or may not contain another cationic polymerization initiator (B02) different from the onium salt (B01) (hereinafter, also simply referred to as "another cationic polymerization initiator (B02)"), either together with the onium salt (B01) or alone.
The curable composition contains another cationic polymerization initiator (B02) together with the onium salt (B01), and thus it is easy to form a metal oxide-containing film that is excellent in refractive index and yellowing resistance, and also has good heat resistance (resistance to thermal decomposition) and adhesion to a substrate.

The other cationic polymerization initiator (B02) may be a thermal cationic polymerization initiator (B02-1) or a photo-cationic polymerization initiator (B02-2), and is preferably a photo-cationic polymerization initiator (B02-2). The thermal cationic polymerization initiator (B02-1) and the photo-cationic polymerization initiator (B02-2) are described below.

Thermal cationic polymerization initiator (B02-1)
Examples of the thermal cationic polymerization initiator (B02-1) include diphenyliodonium hexafluoroarsenate, diphenyliodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, triphenylsulfonium tetrafluoroborate, tri-p-tolylsulfonium hexafluorophosphate, tri-p-tolylsulfonium trifluoromethanesulfonate, bis(cyclohexylsulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, triphenylsulfonium trifluoromethanesulfonate, diphenyl-4-methylphenylsulfonium trifluoromethanesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium-p-toluenesulfonate, and diphenyl-p-phenylthiophenylsulfonium hexafluorophosphate. These may be used in combination of two or more.

Commercially available thermal cationic polymerization initiators include, for example, diazonium salt-type initiators such as the AMERICURE series (American Can), ULTRASET series (Adeka), and WPAG series (Wako Pure Chemical Industries, Ltd.); iodonium salt-type initiators such as the UVE series (General Electric Co., Ltd.), FC series (3M Co., Ltd.), UV9310C (GE Toshiba Silicones Co., Ltd.), and WPI series (Wako Pure Chemical Industries, Ltd.); CYRACURE series Examples of such initiators include sulfonium salt-type initiators such as the AZ1100 (Union Carbide), UVI series (General Electric), FC series (3M), CD series (Sartomer), Optomer SP series (Adeka), Optomer CP series (Adeka), San-Aid SI series (Sanshin Chemical Industry), CI series (Nippon Soda), WPAG series (Wako Pure Chemical Industries), and CPI series (San-Apro).

（式（ｃ０－Ｉ）中、Ｒ^ｃ０１、Ｒ^ｃ０２、及びＲ^ｃ０３は、それぞれ独立に炭素原子数が１以上６以下であるアルキル基である。） The thermal cationic polymerization initiator (B02-1) preferably contains a compound comprising a cationic moiety and an anionic moiety, the cationic moiety being a cation represented by the following formula (c0-I): By using such a thermal cationic polymerization initiator (B02-1), the above-mentioned (A) curable compound can be cured well to form a cured product having excellent refractive index and yellowing resistance, and a curable composition having good heat resistance (resistance to thermal decomposition) and adhesion to a substrate can be easily obtained.

(In formula (c0-I), R ^c01 , R ^c02 , and R ^c03 each independently represent an alkyl group having 1 to 6 carbon atoms.)

In formula (c0-I), suitable examples of the alkyl group as R ^c01 , R ^c02 , and R ^c03 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. As the alkyl group, a methyl group or an ethyl group is preferable, and a methyl group is more preferable. It is particularly preferable that R ^c01 , R ^c02 , and R ^c03 are all methyl groups.

That is, the cation represented by formula (c0-I) is preferably a cation represented by the following formula (c0-II):

Examples of counter anions to the cation represented by formula (c0-I) include AsF ₆ ⁻ , SbF ₆ ⁻ , PF ₆ ⁻ , and ((C ₆ F ₅ ) ₄ B) ^— . Of these, ((C ₆ F ₅ ) ₄ B) ^— is preferred. In addition, “C ₆ F ₅ ” represents a pentafluorophenyl group.

As the compound having a cation portion and an anion portion represented by the above formula (c0-I), a commercially available compound can be used. An example of a commercially available product is CXC-1821 (manufactured by King Industries).

Specific preferred examples of the compound comprising a cation moiety composed of the cation represented by formula (c0-I) and an anion moiety include a quaternary ammonium salt composed of a cation represented by formula (c0-II) and AsF ₆ ^- , a quaternary ammonium salt composed of a cation represented by formula (c0-II) and SbF ₆ ^- , a quaternary ammonium salt composed of a cation represented by formula (c0-II) and PF ₆ ^- , and a quaternary ammonium salt composed of a cation represented by formula (c0-II) and ((C ₆ F ₅ ) ₄ B) ^- . Of these, a quaternary ammonium salt composed of a cation represented by formula (c0-II) and ((C ₆ F ₅ ) ₄ B) ^- is more preferred.

The compound having a cation portion made of the cation represented by formula (c0-I) and an anion portion may be used alone or in combination of two or more.

In the thermal cationic polymerization initiator (B02-1), the amount of the compound consisting of a cationic portion and an anionic portion represented by the above formula (c0-I) is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

The content of the thermal cationic polymerization initiator in the curable composition as the energy-sensitive composition of the fifth embodiment is not particularly limited as long as it does not impair the object of the present invention. The content of the thermal cationic polymerization initiator in the curable composition is preferably 0.01 parts by mass or more and 30 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, and particularly preferably 0.3 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the curable compound.
By using the thermal cationic polymerization initiator in an amount within this range, a metal oxide-containing film having good heat resistance (resistance to thermal decomposition) and adhesion to a substrate, etc. can be formed, and a curable composition having good curability can be easily obtained.

・Photocationic polymerization initiator (B02-2)
As the cationic photopolymerization initiator (B02-2), any polymerization initiator other than the onium salt (B01) used for photocuring a cationic polymerizable curable composition can be used without any particular limitation. Suitable examples of the cationic photopolymerization initiator (B02-2) include iodonium salts and sulfonium salts.

Specific examples of iodonium salts include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, and di(4-nonylphenyl)iodonium hexafluorophosphate.

As the photocationic polymerization initiator (B02-2), a sulfonium salt is preferred. Among the sulfonium salts, a sulfonium salt consisting of a cationic moiety consisting of a cation represented by the following formula (c01) and an anionic moiety (hereinafter also referred to as "sulfonium salt (Q)". In addition, when the onium salt (B01) is a sulfonium salt having a cationic moiety consisting of a cation represented by the following formula (c01), the sulfonium salt is classified as an onium salt (B01).
When the curable composition contains a sulfonium salt (Q), curing of the curable composition tends to proceed particularly well.

（式（ｃ０１）中、Ｒ^ｃ１１及びＲ^ｃ１２は独立に、ハロゲン原子で置換されていてもよいアルキル基又は下記式（ｃ０２）で表される基を示し、Ｒ^ｃ１１及びＲ^ｃ１２は相互に結合して式中の硫黄原子とともに環を形成してもよく、Ｒ^ｃ１３は下記式（ｃ０３）で表される基又は下記式（ｃ０４）で表される基を示し、Ａ^ｃ１はＳ、Ｏ、又はＳｅを示し、但し、Ｒ^ｃ１１及びＲ^ｃ１２は、同時に、ハロゲン原子で置換されていてもよいアルキル基ではない。）

(In formula (c01), R ^c11 and R ^c12 independently represent an alkyl group which may be substituted with a halogen atom or a group represented by the following formula (c02), R ^c11 and R ^c12 may be bonded to each other to form a ring together with the sulfur atom in the formula, R ^c13 represents a group represented by the following formula (c03) or a group represented by the following formula (c04), A ^c1 represents S, O, or Se, with the proviso that R ^c11 and R ^c12 are not simultaneously an alkyl group which may be substituted with a halogen atom.)

（式（ｃ０２）中、環Ｚ^ｃ１は芳香族炭化水素環を示し、Ｒ^ｃ１４はハロゲン原子で置換されていてもよいアルキル基、ヒドロキシ基、アルコキシ基、アルキルカルボニル基、アルコキシカルボニル基、アシロキシ基、アルキルチオ基、チエニル基、チエニルカルボニル基、フラニル基、フラニルカルボニル基、セレノフェニル基、セレノフェニルカルボニル基、脂肪族複素環基、アルキルスルフィニル基、アルキルスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、又はハロゲン原子を示し、ｍ１は０以上の整数を示す。）

(In formula (c02), ring ^Zc1 represents an aromatic hydrocarbon ring, ^Rc14 represents an alkyl group which may be substituted with a halogen atom, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an acyloxy group, an alkylthio group, a thienyl group, a thienylcarbonyl group, a furanyl group, a furanylcarbonyl group, a selenophenyl group, a selenophenylcarbonyl group, an aliphatic heterocyclic group, an alkylsulfinyl group, an alkylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an amino group which may be substituted, a cyano group, a nitro group, or a halogen atom, and m1 represents an integer of 0 or more.)

（式（ｃ０３）中、Ｒ^ｃ１５はヒドロキシ基、アルコキシ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アリールチオカルボニル基、アシロキシ基、アリールチオ基、アルキルチオ基、アリール基、複素環基、アリールオキシ基、アルキルスルフィニル基、アリールスルフィニル基、アルキルスルホニル基、アリールスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、若しくはハロゲン原子で置換されていてもよいアルキレン基又は下記式（ｃ０５）で表される基を示し、Ｒ^ｃ１６はヒドロキシ基、アルコキシ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アリールチオカルボニル基、アシロキシ基、アリールチオ基、アルキルチオ基、アリール基、複素環基、アリールオキシ基、アルキルスルフィニル基、アリールスルフィニル基、アルキルスルホニル基、アリールスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、若しくはハロゲン原子で置換されていてもよいアルキル基又は下記式（ｃ０６）で表される基を示し、Ａ^ｃ２は単結合、Ｓ、Ｏ、スルフィニル基、又はカルボニル基を示し、ｍ２は０又は１を示す。）

In formula (c03), R ^c15 represents a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, an alkylene group optionally substituted with a halogen atom, or a group represented by the following formula (c05): ^c16 represents a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, an alkyl group optionally substituted with a halogen atom, or a group represented by the following formula (c06); A ^c2 represents a single bond, S, O, a sulfinyl group, or a carbonyl group; and m2 represents 0 or 1.

（式（ｃ０４）中、Ｒ^ｃ１７及びＲ^ｃ１８は独立に、ヒドロキシ基、アルコキシ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アリールチオカルボニル基、アシロキシ基、アリールチオ基、アルキルチオ基、アリール基、複素環基、アリールオキシ基、アルキルスルフィニル基、アリールスルフィニル基、アルキルスルホニル基、アリールスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、若しくはハロゲン原子で置換されていてもよいアルキレン基又は下記式（ｃ０５）で表される基を示し、Ｒ^ｃ１９及びＲ^ｃ２０は独立に、ハロゲン原子で置換されていてもよいアルキル基又は上記式（ｃ０２）で表される基を示し、Ｒ^ｃ１９及びＲ^ｃ２０は相互に結合して式中の硫黄原子とともに環を形成してもよく、Ａ^ｃ３は単結合、Ｓ、Ｏ、スルフィニル基、又はカルボニル基を示し、ｍ３は０又は１を示し、但し、Ｒ^ｃ１９及びＲ^ｃ２０は、同時に、ハロゲン原子で置換されていてもよいアルキル基ではない。）

In formula (c04), R ^c17 and R ^c18 independently represent a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, an alkylene group optionally substituted with a halogen atom, or a group represented by the following formula (c05); R ^c19 and R ^c20 independently represent an alkyl group optionally substituted with a halogen atom or a group represented by the above formula (c02); R ^c19 and R ^c20 may be bonded to each other to form a ring together with the sulfur atom in the formula; ^c3 represents a single bond, S, O, a sulfinyl group, or a carbonyl group, m3 represents 0 or 1, and R ^c19 and R ^c20 are not simultaneously an alkyl group optionally substituted with a halogen atom.

（式（ｃ０５）中、環Ｚ^ｃ２は芳香族炭化水素環を示し、Ｒ^ｃ２１はハロゲン原子で置換されていてもよいアルキル基、ヒドロキシ基、アルコキシ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アリールチオカルボニル基、アシロキシ基、アリールチオ基、アルキルチオ基、アリール基、複素環基、アリールオキシ基、アルキルスルフィニル基、アリールスルフィニル基、アルキルスルホニル基、アリールスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、又はハロゲン原子を示し、ｍ４は０以上の整数を示す。）

(In formula (c05), ring ^Zc2 represents an aromatic hydrocarbon ring, ^Rc21 represents an alkyl group which may be substituted with a halogen atom, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, or a halogen atom, and m4 represents an integer of 0 or more.)

（式（ｃ０６）中、環Ｚ^ｃ３は芳香族炭化水素環を示し、Ｒ^ｃ２２はハロゲン原子で置換されていてもよいアルキル基、ヒドロキシ基、アルコキシ基、アルキルカルボニル基、アリールカルボニル基、アルコキシカルボニル基、アリールオキシカルボニル基、アリールチオカルボニル基、アシロキシ基、アリールチオ基、アルキルチオ基、チエニルカルボニル基、フラニルカルボニル基、セレノフェニルカルボニル基、アリール基、複素環基、アリールオキシ基、アルキルスルフィニル基、アリールスルフィニル基、アルキルスルホニル基、アリールスルホニル基、ヒドロキシ（ポリ）アルキレンオキシ基、置換されていてもよいアミノ基、シアノ基、ニトロ基、又はハロゲン原子を示し、ｍ５は０以上の整数を示す。）

(In formula (c06), ring ^Zc3 represents an aromatic hydrocarbon ring, ^Rc22 represents an alkyl group which may be substituted with a halogen atom, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, a thienylcarbonyl group, a furanylcarbonyl group, a selenophenylcarbonyl group, an aryl group, a heterocyclic group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted amino group, a cyano group, a nitro group, or a halogen atom, and m5 represents an integer of 0 or more.)

(Sulfonium Salt (Q))
The sulfonium salt (Q) will be described below. The sulfonium salt (Q) is characterized in that a methyl group is bonded to the carbon atom in the ortho position relative to the carbon atom to which A ^c1 is bonded in the benzene ring in the above formula (c01). Since the sulfonium salt (Q) has a methyl group at the above position, it is more likely to generate protons and has a higher sensitivity to active energy rays such as ultraviolet rays compared to conventional sulfonium salts.

In the above formula (c01), both R ^c11 and R ^c12 are preferably a group represented by the above formula (c02). R ^c11 and R ^c12 may be the same or different.
In the above formula (c01), when R ^c11 and R ^c12 are bonded to each other to form a ring together with the sulfur atom in the formula, the number of ring-constituting atoms of the formed ring, including the sulfur atom, is preferably 3 to 10, and more preferably 5 to 7. The formed ring may be a polycyclic ring, and is preferably one in which 5- to 7-membered rings are condensed.
In the above formula (c01), it is preferable that R ^c11 and R ^c12 are both phenyl groups.
In the above formula (c01), R ^c13 is preferably a group represented by the above formula (c03).
In the above formula (c01), A ^c1 is preferably S or O, and more preferably S.

In the above formula (c02), R ^c14 is preferably an alkyl group which may be substituted with a halogen atom, a hydroxy group, an alkylcarbonyl group, a thienylcarbonyl group, a furanylcarbonyl group, a selenophenylcarbonyl group, an amino group which may be substituted, or a nitro group, and more preferably an alkyl group which may be substituted with a halogen atom, an alkylcarbonyl group, or a thienylcarbonyl group.
In the above formula (c02), m1 can be selected depending on the type of ring ^Zc1 and may be, for example, an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, and more preferably an integer of 0 or more and 2 or less.

In the above formula (c03), R ^c15 is preferably an alkylene group; an alkylene group substituted with a hydroxy group, an optionally substituted amino group, or a nitro group; or a group represented by the above formula (c05), and more preferably a group represented by the above formula (c05).
In the above formula (c03), R ^c16 is preferably an alkyl group; an alkyl group substituted with a hydroxy group, an optionally substituted amino group, or a nitro group; or a group represented by the above formula (c06), more preferably a group represented by the above formula (c06).
In the above formula (c03), A ^c2 is preferably S or O, and more preferably S.
In the above formula (c03), m2 is preferably 0.

In the above formula (c04), R ^c17 and R ^c18 are each independently preferably an alkylene group, an alkylene group substituted with a hydroxyl group, an optionally substituted amino group, or a nitro group, or a group represented by the above formula (c05), more preferably a group represented by the above formula (c05). R ^c17 and R ^c18 may be the same or different from each other.
In the above formula (c04), both of R ^c19 and R ^c20 are preferably a group represented by the above formula (c02). R ^c19 and R ^c20 may be the same or different.
In the above formula (c04), when R ^c19 and R ^c20 are bonded to each other to form a ring together with the sulfur atom in the formula, the number of ring-constituting atoms of the formed ring, including the sulfur atom, is preferably 3 to 10, and more preferably 5 to 7. The formed ring may be a polycyclic ring, and is preferably one in which 5- to 7-membered rings are condensed.
In the above formula (c04), A ^c3 is preferably S or O, and more preferably S.
In the above formula (c04), m3 is preferably 0.

In the above formula (c05), R ^c21 is preferably an alkyl group which may be substituted with a halogen atom, a hydroxy group, an amino group which may be substituted with a halogen atom, or a nitro group, and more preferably an alkyl group which may be substituted with a halogen atom.
In the above formula (c05), m4 can be selected depending on the type of ring ^Zc2 and may be, for example, an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, and more preferably an integer of 0 or more and 2 or less.

In the above formula (c06), R ^c22 is preferably an alkyl group which may be substituted with a halogen atom, a hydroxy group, an alkylcarbonyl group, a thienylcarbonyl group, a furanylcarbonyl group, a selenophenylcarbonyl group, an amino group which may be substituted, or a nitro group, and more preferably an alkyl group which may be substituted with a halogen atom, an alkylcarbonyl group, or a thienylcarbonyl group.
In the above formula (c06), m5 can be selected depending on the type of ring ^Zc3 and may be, for example, an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 3 or less, and more preferably an integer of 0 or more and 2 or less.

The cation represented by the above formula (c01) usually forms a salt together with a monovalent anion X ^- . ^{X -} is a monovalent anion corresponding to an acid (HX) generated by irradiating the sulfonium salt (Q) with active energy (heat, visible light, ultraviolet light, electron beam, X-ray, etc.). Preferred examples of X ^- include monovalent polyatomic anions, and more preferred examples are anions represented by M ¹ Y _a0 ^- , (Rf) _b0 PF _(6-b0) ^- , R ^x1 SO ₃ ^- , (R ^x1 SO ₂ ) ₃ C ^- , or (R ^x1 SO ₂ ) ₂ N ^- . X ^- may also be a halogen anion, and examples thereof include a fluoride ion, a chloride ion, a bromide ion, and an iodide ion.

^M1 represents a phosphorus atom, a boron atom, or an antimony atom.
Y represents a halogen atom (preferably a fluorine atom).

Rf represents an alkyl group in which 80 mol % or more of hydrogen atoms are substituted with fluorine atoms (preferably an alkyl group having 1 to 8 carbon atoms). Examples of the alkyl group which is substituted with fluorine to form Rf include linear alkyl groups (methyl, ethyl, propyl, butyl, pentyl, octyl, etc.), branched alkyl groups (isopropyl, isobutyl, sec-butyl, tert-butyl, etc.), and cycloalkyl groups (cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.). The ratio of hydrogen atoms of these alkyl groups in Rf substituted with fluorine atoms is preferably 80 mol % or more, more preferably 90 mol % or more, and particularly preferably 100%, based on the molar number of hydrogen atoms possessed by the original alkyl group. When the substitution ratio with fluorine atoms is within these preferred ranges, the photosensitivity of the sulfonium salt (Q) becomes even better. Particularly preferred ^examples of Rf include _{CF3- , CF3CF2-} ^, ( _CF3 ) _2CF- ^, _CF3CF2CF2- ^, _{CF3CF2CF2CF2- ,} ( _{CF3 ) 2CFCF2- , CF3CF2} ( _CF3 ) _CF- , and ( _CF3 ) _3C- ^. _The b Rfs are mutually independent and therefore may be ^the same or different _{from each} ^other .

P represents a phosphorus atom and F represents a fluorine atom.

R ^x1 represents an alkyl group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and the alkyl group and the fluoroalkyl group may be linear, branched, or cyclic, and the alkyl group, the fluoroalkyl group, or the aryl group may be unsubstituted or may have a substituent. Examples of the substituent include a hydroxy group, an amino group which may be substituted (for example, those exemplified in the description of the above formulas (c02) to (c06) below), a nitro group, and the like.
In addition, the carbon chain in the alkyl group, fluoroalkyl group or aryl group represented by R ^x1 may have a heteroatom such as an oxygen atom, a nitrogen atom or a sulfur atom. In particular, the carbon chain in the alkyl group or fluoroalkyl group represented by R ^x2 may have a divalent functional group (e.g., an ether bond, a carbonyl bond, an ester bond, an amino bond, an amide bond, an imide bond, a sulfonyl bond, a sulfonylamido bond, a sulfonylimide bond, a urethane bond, etc.).
When the alkyl group, fluoroalkyl group, or aryl group represented by R ^x1 has the above-mentioned substituent, hetero atom, or functional group, the number of the above-mentioned substituent, hetero atom, or functional group may be 1 or 2 or more.

S represents a sulfur atom, O represents an oxygen atom, C represents a carbon atom, and N represents a nitrogen atom.
a0 represents an integer of 4 or more and 6 or less.
b0 is preferably an integer of 1 or more and 5 or less, more preferably an integer of 2 or more and 4 or less, and particularly preferably 2 or 3.

Examples of the anion represented by M ¹ Y _a ^- include anions represented by SbF ₆ ^- , PF ₆ ^- , and BF ₄ ^- .

The anion represented by (Rf) _b PF _6-b ^- includes (CF ₃ CF ₂ ) ₂ PF ₄ ^- , (CF ₃ CF ₂ ) ₃ PF ₃ ^- , ((CF ₃ ) ₂ CF) ₂ PF ₄ ^- , ((CF ₃ ) ₂ CF) ₃ PF ₃ ^- , (CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ^- , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ^- , ((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ^- , ((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ^- , (CF ₃ CF ₂ CF _2CF2 ) _2PF4- ^or _{( CF3CF2CF2CF2} ) _3PF3- . Of these, the anion represented ^by ( _{CF3CF2 ) 3PF3- , ( CF3CF2CF2 ) 3PF3- , ( ( CF3 ) 2CF} ⁾ _{3PF3- , ( ( CF3 ) 2CF} ⁾ _2PF4- ^{, (} ( _{CF3 ) 2CFCF2 ) 3PF3-} ^or (( _{CF3 )} ^2CFCF2 _{) 2PF4- are} preferred.

Examples of the anion represented by R ^x1 SO ₃ ^- include trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonafluorobutanesulfonate anion, pentafluorophenylsulfonate anion, p-toluenesulfonate anion, benzenesulfonate anion, camphorsulfonate anion, methanesulfonate anion, ethanesulfonate anion, propanesulfonate anion, butanesulfonate anion, etc. Among these, trifluoromethanesulfonate anion, nonafluorobutanesulfonate anion, methanesulfonate anion, butanesulfonate anion, camphorsulfonate anion, benzenesulfonate anion, and p-toluenesulfonate anion are preferred.

Examples of the anion represented by (R ^x1 SO ₂ ) ₃ C ^-- include anions represented by (CF ₃ SO ₂ ) ₃ C ^-- , (C ₂ F ₅ SO ₂ ) ₃ C ^-- , (C ₃ F ₇ SO ₂ ) ₃ C ^-- , or (C ₄ F ₉ SO ₂ ) ₃ C ^-- .

Examples of the anion represented by (R ^x1 SO ₂ ) ₂ N ^-- include anions represented by (CF ₃ SO ₂ ) ₂ N ^-- , (C ₂ F ₅ SO ₂ ) ₂ N ^-- , (C ₃ F ₇ SO ₂ ) ₂ N ^-- , or (C ₄ F ₉ SO ₂ ) ₂ N ^-- .

Examples of the monovalent polyatomic anion include, in addition to the anion represented by MY _a ^- , (Rf) _b PF _6-b ^- , R ^x1 SO ₃ ^- , (R ^x1 SO ₂ ) ₃ C ^- or (R ^x2 SO ₂ ) ₂ N ^- , perhalogen acid ions (ClO ₄ ^- , BrO ₄ ^- , etc.), halogenated sulfonate ions (FSO ₃ ^- , ClSO ₃ ^- , etc.), sulfate ions (CH ₃ SO ₄ ^- , CF ₃ SO ₄ ^- , HSO ₄ ^- , etc.), carbonate ions (HCO ₃ ^- , CH ₃ CO ₃ ^- , etc.), aluminate ions (AlCl ₄ ^- , AlF ₄ ^- , etc.), hexafluorobismuthate ion (BiF ₆ ^- ), carboxylate ions (CH ₃ COO ^- , CF ₃ ^{COO- , C6H5COO-} _{, CH3C6H4COO- , C6F5COO-} ^, _{CF3C6H4COO- ,} etc. ₎ , _aryl borate ions (B( _{C6H5 ) 4-} , _{CH3CH2CH2CH2B ( C6H5 ) 3-} ^{, etc.} ₎ , thiocyanate ion ( ^SCN- ), and nitrate ion ( _NO3- ⁾ _, ^etc. _, can be used _.

Among these ^X- , in terms of cationic polymerization performance, anions represented by _MYa- ^, (Rf) _{bPF6 -b-} ^, _and ( ^{Rx1SO2 )} _{3C- are} preferred, ^and _SbF6- ^, _{PF6- ,} ( _CF3CF2 ) _{3PF3- ,} and ( _CF3SO2 ) ^{3C- are} more preferred _.

In the above formulae (c02), (c05), and (c06), examples of the aromatic hydrocarbon ring include a benzene ring, a fused polycyclic aromatic hydrocarbon ring [for example, a fused bicyclic hydrocarbon ring (e.g., a _C8-20 fused bicyclic hydrocarbon ring such as a naphthalene ring, preferably a _C10-16 fused bicyclic hydrocarbon ring), a fused tricyclic aromatic hydrocarbon ring (e.g., an anthracene ring, a phenanthrene ring, etc.) and other fused dicyclic to tetracyclic aromatic hydrocarbon rings], etc. The aromatic hydrocarbon ring is preferably a benzene ring or a naphthalene ring, and more preferably a benzene ring.

In the above formulas (c01) to (c06), examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

In the above formulas (c01) to (c06), examples of the alkyl group include linear alkyl groups having 1 to 18 carbon atoms (methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, and n-octadecyl, etc.), branched alkyl groups having 3 to 18 carbon atoms (isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, and isooctadecyl, etc.), and cycloalkyl groups having 3 to 18 carbon atoms (cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and 4-decylcyclohexyl, etc.). In particular, in the above formulas (c01), (c02), and (c04) to (c06), the alkyl group which may be substituted with a halogen atom means an alkyl group and an alkyl group substituted with a halogen atom. Examples of the alkyl group substituted with a halogen atom include the above-mentioned linear alkyl group, branched alkyl group, or cycloalkyl group in which at least one hydrogen atom is substituted with a halogen atom (monofluoromethyl, difluoromethyl, trifluoromethyl, etc.). Among the alkyl groups which may be substituted with a halogen atom, for R, ^R , ^R , ^R , or ^R , a trifluoromethyl group is particularly preferred, and for R, ^R , ^{R ,} R, or ^R , a methyl group is particularly preferred.

In the above formulas (c02) to (c06), examples of the alkoxy group include linear or branched alkoxy groups having 1 to 18 carbon atoms (such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, dodecyloxy, and octadecyloxy).

In the above formulas (c02) to (c06), examples of the alkyl group in the alkylcarbonyl group include the above-mentioned linear alkyl group having 1 to 18 carbon atoms, branched alkyl group having 3 to 18 carbon atoms, and cycloalkyl group having 3 to 18 carbon atoms. Examples of the alkylcarbonyl group include linear, branched, or cyclic alkylcarbonyl groups having 2 to 18 carbon atoms (acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl, decanoyl, dodecanoyl, octadecanoyl, cyclopentanoyl, and cyclohexanoyl groups, etc.).

In the above formulas (c03) to (c06), examples of the arylcarbonyl group include arylcarbonyl groups having 7 to 11 carbon atoms (such as benzoyl and naphthoyl).

In the above formulas (c02) to (c06), examples of the alkoxycarbonyl group include linear or branched alkoxycarbonyl groups having 2 to 19 carbon atoms (such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, and octadecyloxycarbonyl).

In the above formulas (c03) to (c06), examples of the aryloxycarbonyl group include aryloxycarbonyl groups having 7 to 11 carbon atoms (such as phenoxycarbonyl and naphthoxycarbonyl).

In the above formulas (c03) to (c06), examples of the arylthiocarbonyl group include arylthiocarbonyl groups having 7 to 11 carbon atoms (such as phenylthiocarbonyl and naphthoxythiocarbonyl).

In the above formulas (c02) to (c06), examples of the acyloxy group include linear or branched acyloxy groups having 2 to 19 carbon atoms (acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyloxy, etc.).

In the above formulas (c03) to (c06), the arylthio group is an arylthio group having 6 to 20 carbon atoms (phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-chlorophenylthio, 3-chlorophenylthio, 4-chlorophenylthio, 2-bromophenylthio, 3-bromophenylthio, 4-bromophenylthio, 2-fluorophenylthio, 3-fluorophenylthio, 4-fluorophenylthio, 2-hydroxyphenylthio, 4-hydroxyphenylthio, 2-methoxyphenylthio, 4-methoxyphenylthio, 1-naphthylthio, 2-naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, 4-[4 -(phenylthio)phenoxy]phenylthio, 4-[4-(phenylthio)phenyl]phenylthio, 4-(phenylthio)phenylthio, 4-benzoylphenylthio, 4-benzoyl-2-chlorophenylthio, 4-benzoyl-3-chlorophenylthio, 4-benzoyl-3-methylthiophenylthio, 4-benzoyl-2-methylthiophenylthio, 4-(4-methylthiobenzoyl)phenylthio, 4-(2-methylthiobenzoyl)phenylthio, 4-(p-methylbenzoyl)phenylthio, 4-(p-ethylbenzoyl)phenylthio, 4-(p-isopropylbenzoyl)phenylthio, and 4-(p-tert-butylbenzoyl)phenylthio, etc.

In the above formulas (c02) to (c06), examples of the alkylthio group include linear or branched alkylthio groups having 1 to 18 carbon atoms (such as methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, tert-butylthio, pentylthio, isopentylthio, neopentylthio, tert-pentylthio, octylthio, decylthio, dodecylthio, and isooctadecylthio).

In the above formulas (c03) to (c06), examples of the aryl group include aryl groups having 6 to 10 carbon atoms (such as phenyl, tolyl, dimethylphenyl, and naphthyl).

In the above formula (c02), examples of the aliphatic heterocyclic group include aliphatic heterocyclic groups having 2 to 20 carbon atoms (preferably 4 to 20 carbon atoms) (pyrrolidinyl, tetrahydrofuranyl, tetrahydrothienyl, piperidinyl, tetrahydropyranyl, tetrahydrothiopyranyl, morpholinyl, etc.).

In the above formulas (c03) to (c06), examples of the heterocyclic group include heterocyclic groups having 4 to 20 carbon atoms (thienyl, furanyl, selenophenyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, dibenzofuranyl, etc.).

In the above formulas (c03) to (c06), examples of the aryloxy group include aryloxy groups having 6 to 10 carbon atoms (such as phenoxy and naphthyloxy).

In the above formulas (c02) to (c06), examples of the alkylsulfinyl group include linear or branched sulfinyl groups having 1 to 18 carbon atoms (methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, tert-pentylsulfinyl, octylsulfinyl, isooctadecylsulfinyl, etc.).

In the above formulas (c03) to (c06), examples of the arylsulfinyl group include arylsulfinyl groups having 6 to 10 carbon atoms (such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl).

In the above formulas (c02) to (c06), examples of the alkylsulfonyl group include linear or branched alkylsulfonyl groups having 1 to 18 carbon atoms (methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, tert-pentylsulfonyl, octylsulfonyl, and octadecylsulfonyl, etc.).

In the above formulas (c03) to (c06), examples of the arylsulfonyl group include arylsulfonyl groups having 6 to 10 carbon atoms (such as phenylsulfonyl, tolylsulfonyl (tosyl group), and naphthylsulfonyl).

In the above formulas (c02) to (c06), examples of the hydroxy(poly)alkyleneoxy group include a hydroxy(poly)alkyleneoxy group represented by HO(AO) _q0- (wherein, AO independently represent an ethyleneoxy group and/or a propyleneoxy group, and q0 represents an integer of 1 or more and 5 or less).

In the above formulas (c02) to (c06), examples of the optionally substituted amino group include an amino group (-NH ₂ ) and a substituted amino group having 1 to 15 carbon atoms (methylamino, dimethylamino, ethylamino, methylethylamino, diethylamino, n-propylamino, methyl-n-propylamino, ethyl-n-propylamino, n-propylamino, isopropylamino, isopropylmethylamino, isopropylethylamino, diisopropylamino, phenylamino, diphenylamino, methylphenylamino, ethylphenylamino, n-propylphenylamino, and isopropylphenylamino, etc.).

In the above formulas (c03) and (c04), the alkylene group is a straight-chain or branched-chain alkylene group having 1 to 18 carbon atoms (e.g., methylene group, 1,2-ethylene group, 1,1-ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, propane-1,1-diyl group, propane-2,2-diyl group, butane-1,4-diyl group, butane-1,3-diyl group, butane-1,2-diyl group, butane-1,1-diyl group, butane-2,2-diyl group, butane-2,3-diyl group, pentaerythritol group, hexane-1,5-diyl group, pentane-1,4-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, 2-ethylhexane-1,6-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, and hexadecane-1,16-diyl group, etc.

The sulfonium salt (Q) can be synthesized, for example, according to the following scheme. Specifically, 1-fluoro-2-methyl-4-nitrobenzene represented by the following formula (c1-1) is reacted with a compound represented by the following formula (c1-2) in the presence of a base such as potassium hydroxide to obtain a nitro compound represented by the following formula (c1-3), which is then reduced in the presence of reduced iron to obtain an amine compound represented by the following formula (c1-4). This amine compound is reacted with a nitrite salt (e.g., sodium nitrite) represented by MaNO ₂ (wherein Ma represents a metal atom, for example, an alkali metal atom such as a sodium atom) to obtain a diazo compound, which is then mixed with a cuprous halide represented by CuX' (wherein X' represents a halogen atom such as a bromine atom; the same applies below) and a hydrogen halide represented by HX' to allow the reaction to proceed, thereby obtaining a halide represented by the following formula (c1-5). A Grignard reagent is prepared from this halide and magnesium, and then this Grignard reagent is reacted with a sulfoxide compound represented by the following formula (c1-6) in the presence of chlorotrimethylsilane to obtain a sulfonium salt represented by the following formula (c1-7). Furthermore, this sulfonium salt is reacted with a salt represented by Mb ⁺ X" ^- (wherein Mb ⁺ represents a metal cation, for example an alkali metal cation such as potassium ion, and X" ^- represents a monovalent anion represented by X ^- (excluding halogen anions)) to perform salt exchange, to obtain a sulfonium salt represented by the following formula (c1-8). In the following formulas (c1-2) to (c-8), R ^c11 to R ^c13 and A ^c1 are the same as those in the above formula (c01).

<Scheme>

Specific examples of the cation moiety of the sulfonium salt (Q), which is represented by formula (c01), include the following. Specific examples of the anion moiety of the sulfonium salt (Q) include those conventionally known, such as those described above for ^X- . The sulfonium salt (Q) containing the cation moiety represented by formula (c01) can be synthesized according to the above scheme, and the cation moiety can be combined with a desired anion moiety by further salt exchange, if necessary.

Among the above group of preferred cationic moieties, cationic moieties represented by the following formula are more preferred.

The other cationic polymerization initiator (B02) may contain, together with the above-mentioned sulfonium salt (Q), a photocationic polymerization initiator other than the sulfonium salt (Q).
The content of the sulfonium salt (Q) in the other cationic polymerization initiator (B02) is not particularly limited, but is typically preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

The cationic photopolymerization initiator (B02-2) may further contain, in addition to the sulfonium salt (Q), a cationic photopolymerization initiator other than the onium salt (B01) and the sulfonium salt (Q).
As the photocationic polymerization initiator other than the above-mentioned onium salt (B01) and sulfonium salt (Q), various cationic polymerization initiators that have been conventionally used for cationic polymerization can be used without any particular limitation.
As the photocationic polymerization initiator other than the onium salt (B01) and the sulfonium salt (Q), as described above, an onium salt such as an iodonium salt or a sulfonium salt is preferable, and a sulfonium salt other than the sulfonium salt (Q) is more preferable.

The total content of the photocationic polymerization initiator in the curable composition is not particularly limited as long as the curing of the curable composition proceeds well. From the viewpoint of facilitating good curing of the curable composition, typically, the content is preferably 0.001 parts by mass or more and 30 parts by mass or less, more preferably 0.01 parts by mass or more and 10 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the curable compound.

Radical Polymerization Initiator In the energy-sensitive composition of the fifth embodiment, when the curable compound contains a radical polymerizable compound containing an unsaturated double bond, the radical polymerization initiator is not particularly limited, and a conventionally known photopolymerization initiator that has been conventionally used to polymerize a radical polymerizable compound containing an unsaturated double bond can be used. As such a radical polymerization initiator, the photopolymerization initiator described for the energy-sensitive composition of the first embodiment can be suitably used.

The content of the radical polymerization initiator is preferably 0.01 parts by mass or more and 50 parts by mass or less, more preferably 0.1 parts by mass or more and 30 parts by mass or less, and particularly preferably 0.3 parts by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the curable compound. By setting the content of the radical polymerization initiator within the above range, the curable composition can be easily cured well.

In addition, a photoinitiator assistant may be combined with the radical polymerization initiator. Examples of the photoinitiator assistant include triethanolamine, methyldiethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethyl-p-toluidine, 4,4'-bis(dimethylamino)benzophenone, 9,10-dimethoxyanthracene, 2-ethyl-9,10- Examples of thiol compounds include dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-diethoxyanthracene, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercapto-5-methoxybenzothiazole, 3-mercaptopropionic acid, methyl 3-mercaptopropionate, pentaerythritol tetramercaptoacetate, and 3-mercaptopropionate. These photoinitiator assistants can be used alone or in combination of two or more.

The curable composition as the energy-sensitive composition of the fifth aspect may contain a curing accelerator. When the curable composition contains a curing accelerator, the curable composition has good curability and properties after curing.

Examples of hardening accelerators include urea compounds, tertiary amines and their salts, imidazoles and their salts, phosphine compounds and their derivatives, metal carboxylates, Lewis acids, Bronsted acids and their salts, and tetraphenylboron salts.

Specific examples of preferred curing accelerators include tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, and tetraphenylboron salts of N-methylmorpholine tetraphenylborate.

Among the curing accelerators described above, phosphine compounds and their derivatives, and tetraphenylboron salts are preferred. Among the specific examples above, triphenylphosphine and triphenylphosphinetriphenylborane are preferred.

The amount of the curing accelerator used is not particularly limited as long as it does not impede the object of the present invention. The amount of the curing accelerator used is preferably 0.5 parts by mass or more and 8 parts by mass or less, more preferably 1.5 parts by mass or more and 6 parts by mass or less, and particularly preferably 3 parts by mass or more and 4.5 parts by mass or less, based on 1 part by mass of the curing agent.

The curable composition as the energy-sensitive composition of the fifth embodiment may contain a sensitizer. When the curable composition contains a photocationic polymerization initiator, it is preferable that the curable composition contains a sensitizer. As the sensitizer, any known sensitizer that has been conventionally used in combination with various cationic polymerization initiators can be used without any particular restrictions.

Specific examples of sensitizers include anthracene compounds such as anthracene, 9,10-dibutoxyanthracene, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, and 9,10-dipropoxyanthracene; pyrene; 1,2-benzanthracene; perylene; tetracene; coronene; thioxanthone compounds such as thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 2,4-diethylthioxanthone; phenothiazine compounds such as phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, and N-phenylphenothiazine; xanthone; 1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dihydro naphthalene compounds such as roxynaphthalene and 4-methoxy-1-naphthol; ketones such as dimethoxyacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, and 4-benzoyl-4'-methyldiphenyl sulfide; carbazole compounds such as N-phenylcarbazole, N-ethylcarbazole, poly-N-vinylcarbazole, and N-glycidylcarbazole; chrysene compounds such as 1,4-dimethoxychrysene and 1,4-di-α-methylbenzyloxychrysene; and phenanthrene compounds such as 9-hydroxyphenanthrene, 9-methoxyphenanthrene, 9-hydroxy-10-methoxyphenanthrene, and 9-hydroxy-10-ethoxyphenanthrene.
These sensitizers may be used in combination of two or more kinds.

The amount of sensitizer used is not particularly limited, but is preferably 1% by mass or more and 300% by mass or less, and more preferably 5% by mass or more and 200% by mass or less, relative to the mass of the photocationic polymerization initiator. By using an amount of sensitizer within this range, it is easy to obtain the desired sensitization effect.

The curable composition as the energy-sensitive composition of the fifth embodiment may contain additives such as surfactants, thermal polymerization inhibitors, defoamers, silane coupling agents, colorants (pigments, dyes), resins (thermoplastic resins, alkali-soluble resins, etc.), inorganic fillers other than the metal oxide (A), and organic fillers, as necessary. Any of the additives may be used that are conventionally known. Examples of surfactants include anionic, cationic, and nonionic compounds, examples of thermal polymerization inhibitors include hydroquinone and hydroquinone monoethyl ether, and examples of defoamers include silicone and fluorine-based compounds.

The curable composition as the energy-sensitive composition of the fifth embodiment preferably contains a solvent for the purpose of adjusting the coatability and viscosity. An organic solvent is typically used as the solvent. There are no particular limitations on the type of organic solvent as long as it can uniformly dissolve or disperse the components contained in the curable composition.

Suitable examples of organic solvents that can be used as the solvent are the same as the suitable examples of organic solvents in the energy-sensitive composition of the first embodiment.

The amount of the solvent used in the curable composition as the energy-sensitive composition of the fifth embodiment is not particularly limited. In terms of the applicability of the curable composition, the amount of the solvent used is, for example, 30% by mass or more and 99.9% by mass or less, preferably 50% by mass or more and 98% by mass or less, based on the entire curable composition. In addition, it is preferable to adjust the viscosity of the curable composition to a range of 300 mPa·s or less. The viscosity of the curable composition is more preferably 60 mPa·s or less, particularly preferably 30 mPa·s or less. There is no particular lower limit, but it is 0.1 mPa·s or more.
The above viscosity is measured at 25° C. using an E-type viscometer.

By using a curable composition containing the essential or optional components described above, a cured product having a high refractive index can be formed. Therefore, the curable composition can be preferably used for forming high refractive index materials and high refractive index films, which have conventionally been used for various applications.
For example, when the above curable composition is used, a cured product can be formed having a refractive index of 1.70 or more, preferably 1.72 or more, more preferably 1.75 or more, even more preferably 1.80 or more, and most preferably 1.80 or more.
The curable composition is particularly preferably used for forming a transparent coating for covering metal wiring and the like in a display element such as a touch panel.
When the above-mentioned curable composition is used to form a transparent film, the transparent film has a high refractive index, making it difficult to visually recognize the metal wiring.

Furthermore, a cured film formed using the above curable composition has excellent bending resistance and is unlikely to crack even when bent, and is therefore suitable for use in flexible display panels.
For example, when a 50 nm thick film made of the cured product of the above-mentioned curable composition is wrapped around a cylindrical stainless steel rod with a radius of 6 mm, preferably 2 mm, cracks are unlikely to occur.

(6) Energy-Sensitive Composition of Sixth Aspect The energy-sensitive composition of the sixth aspect is a cationically curable or anionically curable composition containing a metal oxide (A), a base component (B), and an ionic liquid having a melting point of 140° C. or lower.
When the curable composition contains the above-mentioned ionic liquid, the curing reaction can be promoted uniformly in the curable composition with little dependency on whether cationic polymerization or anionic polymerization is performed, and as a result, a metal oxide-containing film can be formed that has excellent refractive index and yellowing resistance (particularly yellowing resistance) and also has good heat resistance and adhesion to the substrate.
Essential and optional components contained in the curable composition will be described below.

(Curable Compound)
From the viewpoints of refractive index and yellowing resistance, and also heat resistance and adhesion to a substrate, the curable composition preferably contains a curable compound having a functional group containing at least one element selected from the group consisting of N, O, S, and Si.

A curable compound having a functional group containing at least one element selected from the group consisting of N, O, S, and Si tends to have a relatively high refractive index.
From the viewpoint of a high refractive index, the curable compound preferably has a functional group containing at least one element selected from the group consisting of N, S, and O, and more preferably has a functional group containing at least one element selected from the group consisting of N and S.

Examples of functional groups containing N include triazine ring structures, isocyanuric ring structures, carbazole groups, imide groups, and nitrile groups. Examples of (A) curable compounds having a functional group containing N include polymers having triazine rings, compounds represented by the above formula (a1-I) as epoxy resin precursors, polyvinylcarbazole (PVK), polyimides, and the like. Polymers having triazine rings are particularly preferred because their structure gives them a relatively high refractive index (1.70 or more).

Examples of the functional group containing O include an epoxy group, an isocyanuric ring structure, a carboxyl group, an ester group, a ketone group, and a hydroxyl group.
Examples of the curable compound having a functional group containing O include the compound represented by the formula (b-01) described above, and the epoxy compounds described above as the epoxy resin precursor.

Examples of functional groups containing S include a thiirane group, a sulfonyl group (—SO ₂ —), a thiol group, and a thioester group.
Examples of the curable compound having a functional group containing S include the compound represented by the above formula (b-01), polyethersulfone (PES), polysulfone, and polyphenylsulfone.
Examples of the curable compound having a functional group containing Si include a siloxane compound having a siloxane skeleton formed of siloxane bonds (Si-O-Si). Examples of the siloxane skeleton in the siloxane compound include a cyclic siloxane skeleton and a cage-type or ladder-type polysilsesquioxane skeleton.

From the viewpoints of the refractive index and yellowing resistance of the metal oxide-containing film, and also of the heat resistance and adhesion to the substrate, it is preferable that the curable compound contains at least one selected from the group consisting of an aromatic group, a triazine ring structure, an isocyanuric ring structure, and a cyclic siloxane structure.
From the viewpoints of refractive index and yellowing resistance, as well as heat resistance and adhesion to a substrate, the aromatic group is preferably an aromatic group that forms a cardo structure.

From the viewpoints of refractive index and yellowing resistance, as well as heat resistance and adhesion to the substrate, the curable compound preferably contains at least one selected from the group consisting of the above-mentioned formula (b-01), a polymer having a triazine ring structure, a compound represented by the above-mentioned formula (a1-I) as an epoxy resin precursor, and a siloxane epoxy compound represented by the above-mentioned formula (a1-III) as an epoxy resin precursor.

When the curable compound contains a compound represented by the aforementioned formula (b-01), the amount of the compound represented by the aforementioned formula (b-01) in the curable compound is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

As the epoxy compound as the curable compound, the epoxy compound described above as the epoxy resin precursor can be used.

Episulfide Compound The type of episulfide compound is not particularly limited as long as it does not impede the object of the present invention. Preferable episulfide compounds include compounds in which the oxygen atom in the epoxy group of the above-mentioned epoxy compound is replaced with a sulfur atom.

Vinyl Ether Compound The curable compound may or may not contain a vinyl ether compound containing a vinyloxy group.
The vinyl ether compound is not particularly limited as long as it has a vinyloxy group and is cationic polymerizable.
The vinyl ether compound may or may not contain an aromatic group.
From the viewpoint of obtaining a cured product with good thermal decomposition resistance, the vinyl ether compound is preferably a compound having a vinyloxy group bonded to an aromatic group.

Specific examples of suitable vinyl ether compounds include vinyl phenyl ether, 4-vinyloxytoluene, 3-vinyloxytoluene, 2-vinyloxytoluene, 1-vinyloxy-4-chlorobenzene, 1-vinyloxy-3-chlorobenzene, 1-vinyloxy-2-chlorobenzene, 1-vinyloxy-2,3-dimethylbenzene, 1-vinyloxy-2,4-dimethylbenzene, 1-vinyloxy-2,5-dimethylbenzene, and 1-vinyloxy-2,6-dimethylbenzene. Aromatic monovinyl ethers such as methylbenzene, 1-vinyloxy-3,4-dimethylbenzene, 1-vinyloxy-3,5-dimethylbenzene, 1-vinyloxynaphthalene, 2-vinyloxynaphthalene, 2-vinyloxyfluorene, 3-vinyloxyfluorene, 4-vinyloxy-1,1'-biphenyl, 3-vinyloxy-1,1'-biphenyl, 2-vinyloxy-1,1'-biphenyl, 6-vinyloxytetralin, and 5-vinyloxytetralin. Compound: 1,4-divinyloxybenzene, 1,3-divinyloxybenzene, 1,2-divinyloxybenzene, 1,4-divinyloxynaphthalene, 1,3-divinyloxynaphthalene, 1,2-divinyloxynaphthalene, 1,5-divinyloxynaphthalene, 1,6-divinyloxynaphthalene, 1,7-divinyloxynaphthalene, 1,8-divinyloxynaphthalene, 2,3-divinyloxynaphthalene, 2,6-divinyloxynaphthalene, 2,7-divinyloxy aromatic divinyloxy ether compounds such as bisphenol A divinyl ether, and the like.
These vinyl ether compounds may be used in combination of two or more kinds.

Polymer Having a Triazine Ring Structure The polymer having a triazine ring structure is preferably used in combination with the other curable compounds described above.
Examples of the polymer having the above-mentioned triazine ring structure (hereinafter also simply referred to as "triazine ring-containing polymer") include those represented by the following formulae (t1) to (t16).

In the above formula, R ^t0 and R ^t1 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group, and from the viewpoint of further increasing the refractive index, it is preferable that both are hydrogen atoms. R ^t2 to R ^t4 and R ^t6 to R ^t9 each independently represent a hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, an alkyl group having 1 to 10 carbon atoms which may have a branched structure, or an alkoxy group having 1 to 10 carbon atoms which may have a branched structure, and R ¹⁰² and R ¹⁰³ each independently represent an alkyl group having 1 to 5 carbon atoms.

（式中、Ｒ^ｔ０～Ｒ^ｔ４、Ｒ^ｔ６～Ｒ^ｔ９、Ｒ^１０２及びＲ^１０３は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t4 , R ^t6 to R ^t9 , R ¹⁰² and R ¹⁰³ have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ４、及びＲ^ｔ６～Ｒ^ｔ９は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t4 and R ^t6 to R ^t9 have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ４、及びＲ^ｔ６～Ｒ^ｔ９は上記と同じ意味を表し、Ｒ^ｔ５は水素原子、ハロゲン原子、カルボキシル基、スルホ基、炭素原子数１以上１０以下の分岐構造を有していてもよいアルキル基、又は炭素原子数１以上１０以下の分岐構造を有していてもよいアルコキシ基を表し、Ｒ^１０２及びＲ^１０３は、互いに独立して炭素原子数１以上５以下のアルキル基を表す。）

(In the formula, R ^t0 to R ^t4 and R ^t6 to R ^t9 are the same as defined above, R ^t5 represents a hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, an alkyl group having from 1 to 10 carbon atoms which may have a branched structure, or an alkoxy group having from 1 to 10 carbon atoms which may have a branched structure, and R ¹⁰² and R ¹⁰³ each independently represent an alkyl group having from 1 to 5 carbon atoms.)

（式中、Ｒ^ｔ０～Ｒ^ｔ９、Ｒ^１０２及びＲ^１０３は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t9 , R ¹⁰² and R ¹⁰³ have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ９は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t9 have the same meaning as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ４、Ｒ^ｔ６～Ｒ^ｔ９は上記と同じ意味を表し、Ｒ^１０２及びＲ^１０３は、互いに独立して炭素原子数１以上５以下のアルキル基を表す。）

(In the formula, R ^t0 to R ^t4 and R ^t6 to R ^t9 are the same as defined above, and R ¹⁰² and R ¹⁰³ each independently represent an alkyl group having 1 to 5 carbon atoms.)

（式中、Ｒ^ｔ０～Ｒ^ｔ４、Ｒ^ｔ６～Ｒ^ｔ９、Ｒ^１０２及びＲ^１０３は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t4 , R ^t6 to R ^t9 , R ¹⁰² and R ¹⁰³ have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ４、Ｒ^ｔ６～Ｒ^ｔ９は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t4 and R ^t6 to R ^t9 have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ９は上記と同じ意味を表し、Ｒ^１０２及びＲ^１０３は、互いに独立して炭素原子数１以上５以下のアルキル基を表す。）

(In the formula, R ^t0 to R ^t9 are the same as defined above, and R ¹⁰² and R ¹⁰³ each independently represent an alkyl group having 1 to 5 carbon atoms.)

（式中、Ｒ^ｔ０～Ｒ^ｔ９、Ｒ^１０２及びＲ^１０３は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t9 , R ¹⁰² and R ¹⁰³ have the same meanings as above.)

（式中、Ｒ^ｔ０～Ｒ^ｔ９は、上記と同じ意味を表す。）

(In the formula, R ^t0 to R ^t9 have the same meaning as above.)

The weight average molecular weight (Mw) of the triazine ring-containing polymer is not particularly limited. The weight average molecular weight (Mw) of the triazine ring-containing polymer is preferably 500 or more and 500,000 or less, more preferably 500 or more and 100,000 or less. From the viewpoint of easily achieving the effects of the present invention, it is preferably 2,000 or more, and from the viewpoint of further increasing the solubility and reducing the viscosity of the obtained solution, it is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 10,000 or less.
The weight average molecular weight (Mw) is an average molecular weight obtained by gel permeation chromatography (hereinafter referred to as GPC) analysis in terms of standard polystyrene.

Triazine ring-containing polymers can be produced, for example, by the method disclosed in WO 2010/128661.

The triazine ring-containing polymer has at least one diamine end, and it is preferable that at least one of the diamine ends is blocked with a carbonyl-containing group such as an acyl group, an alkoxycarbonyl group, an aralkyloxycarbonyl group, or an aryloxycarbonyl group. In this way, by blocking the end with a carbonyl-containing group, coloration of the triazine ring-containing polymer can be suppressed.

Specific examples of the acyl group include an acetyl group, an ethylcarbonyl group, an acryloyl group, a methacryloyl group, and a benzoyl group.
Specific examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, and a tert-butoxycarbonyl group.
Specific examples of the aralkyloxycarbonyl group include a benzyloxycarbonyl group.
Specific examples of the aryloxycarbonyl group include a phenoxycarbonyl group.
Among these, the end-capping group is preferably an acyl group, and in consideration of the availability of reagents, etc., an acryloyl group, a methacryloyl group, and an acetyl group are more preferable.

The terminals may be blocked by known methods, for example, by treatment with an acid halide, an acid anhydride or the like.
In this case, the amount of the end-capping agent used is preferably about 0.05 equivalents or more and 10 equivalents or less, more preferably 0.1 equivalents or more and 5 equivalents or less, and even more preferably 0.5 equivalents or more and 2 equivalents or less, relative to 1 equivalent of the amino group derived from the excess diamino compound not used in the polymerization reaction.

The above curable compounds may be used alone or in combination.
The content of the curable compound in the curable composition is not particularly limited as long as it does not impair the object of the present invention. The content of the curable compound in the curable composition is preferably 60 parts by mass or more and 99.9 parts by mass or less, more preferably 75 parts by mass or more and 99.5 parts by mass or less, and particularly preferably 90 parts by mass or more and 99 parts by mass or less, when the total solid content of the curable composition is 100 parts by mass.

(Hardening agent)
The curable composition preferably contains a curing agent, which may be the same as the curing agent described for the energy-sensitive composition of the fifth embodiment.

The content of the cationic polymerization initiator as a curing agent in the curable composition is not particularly limited as long as it does not impair the object of the present invention. The content of the cationic polymerization initiator in the curable composition is, as the total amount of the onium salt (B01) and the other cationic polymerization initiator (B02), preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 2 parts by mass or less, relative to 100 parts by mass of the curable compound.
The content of the onium salt (B01) is preferably 10% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass, based on the total amount of the sulfonium salt (B01) and the other cationic polymerization initiator (B02) described later.
By using the cationic polymerization initiator in an amount within this range, it is easy to form a metal oxide-containing film that has excellent refractive index and yellowing resistance, as well as good heat resistance (resistance to thermal decomposition) and adhesion to the substrate.

When the curable composition is anionically polymerizable, an anionic polymerization initiator can be used as the curing agent. The anionic polymerization initiator may be a photo-induced anionic polymerization initiator or a heat-induced anionic polymerization initiator.
For example, when the above-mentioned epoxy compound is blended with an anionic polymerization initiator in a curable composition, an anionic curable composition can be obtained.
The photo-induced anionic polymerization initiator is not particularly limited, but examples thereof include photoactive carbamates such as triphenylmethanol, benzyl carbamate, and benzoin carbamate; amides such as O-carbamoylhydroxylamide, O-carbamoyloxime, aromatic sulfonamide, alpha-lactam, and N-(2-allylethynyl)amide, as well as other amides; oxime ester compounds, α-aminoacetophenone, and cobalt complexes. Of these, preferred examples include 2-nitrobenzyl cyclohexyl carbamate, triphenylmethanol, o-carbamoyl hydroxylamide, o-carbamoyl oxime, [[(2,6-dinitrobenzyl)oxy]carbonyl]cyclohexylamine, bis[[(2-nitrobenzyl)oxy]carbonyl]hexane 1,6-diamine, 4-(methylthiobenzoyl)-1-methyl-1-morpholinoethane, (4-morpholinobenzoyl)-1-benzyl-1-dimethylaminopropane, N-(2-nitrobenzyloxycarbonyl)pyrrolidine, hexaamminecobalt(III) tris(triphenylmethylborate), and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone.
Other suitable examples include compounds that decompose under the action of light (and/or heat) to generate an imidazole compound, such as compounds represented by formula (d2) or (d3).
As the thermal anionic polymerization initiator, any compound that has been conventionally used can be used without any particular limitation, and examples thereof include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one and other amine-epoxy adduct-based thermal anionic polymerization initiators, thermal base generators consisting of amine-isocyanate-based compounds, anionic polymerization curing agents such as dicyandiamides, hydrazines, or aromatic diamines, and composite anionic polymerization curing agents consisting of different types of curing agents. Examples of the amine-epoxy adduct thermal anionic polymerization initiator include "Amicure PN-23", "Amicure PN-40", "Amicure PN-50", "Amicure PN-H" (all trade names of Ajinomoto Fine-Techno Co., Ltd.), "Hardener X-3661S" (trade name of ACS Corporation), "Hardener X-3670S" (trade name of ACS Corporation), "Novacure HX-3742" (trade name of Asahi Kasei Corporation), and "Novacure HX-3721" (trade name of Asahi Kasei Corporation). Examples of the thermal base generator consisting of an amine-isocyanate compound include "Fujicure FXE-1000" (trade name of Fuji Kasei Corporation), and "Fujicure FXR-1030" (trade name of Fuji Kasei Corporation). Incidentally, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one can also function as an anionic polymerization initiator by the action of light.

The content of the anionic polymerization initiator in the curable composition is not particularly limited as long as it does not impair the object of the present invention. The content of the anionic polymerization initiator in the curable composition is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 2 parts by mass or less, relative to 100 parts by mass of the curable compound.

(Ionic liquid with a melting point of 140° C. or less (hereinafter, simply referred to as “ionic liquid”))
The ionic liquid is a salt that can melt in a temperature range of 140° C. or less, and is preferably a stable salt that becomes liquid at 140° C. or less.
From the viewpoint of more reliably achieving the effects of the present invention and from the viewpoint of coatability, the melting point of the ionic liquid is preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower.
When the curable composition contains a solvent, from the viewpoints of more reliably achieving the effects of the present invention, coatability, suppression of foreign matter, and the like, the solubility of the ionic liquid in the solvent contained in the curable composition at room temperature (25° C.) is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

The solubility refers to the mass at which no precipitation is observed when 70 parts by mass, 80 parts by mass, 90 parts by mass, etc. of the ionic liquid is mixed with 100 parts by mass of the solvent contained in the curable composition and treated with a shaker for 5 minutes, and a visual check is performed to see whether or not there is precipitation.
Ionic liquids are salts, so they have good ionic conductivity, and are liquid with a melting point of 140° C. or less, so they can be uniformly diffused in the curable composition. In addition, their thermal decomposition temperature is relatively high. Therefore, in the curable composition, the curing reaction can be uniformly promoted with little dependency on whether the polymerization is cationic or anionic, and as a result, a metal oxide-containing film can be formed that is excellent in refractive index and yellowing resistance (especially yellowing resistance), and also has good heat resistance and adhesion to the substrate.

The ionic liquid is preferably composed of an organic cation and an anion.
The ionic liquid preferably comprises a nitrogen-containing organic cation, a phosphorus-containing organic cation, or a sulfur-containing organic cation, and a counter anion, and more preferably comprises a nitrogen-containing organic cation or a phosphorus-containing organic cation, and a counter anion.

As the organic cation constituting the ionic liquid, it is preferable to use at least one selected from the group consisting of alkyl chain quaternary ammonium cation, piperidinium cation, pyrimidinium cation, pyrrolidinium cation, imidazolium cation, pyridinium cation, pyrazolium cation, guanidinium cation, morpholinium cation, phosphonium cation, and sulfonium cation, because of its good affinity with the solvent described below, and it is more preferable to use an alkyl chain quaternary ammonium cation, piperidinium cation, pyrrolidinium cation, imidazolium cation, morpholinium cation, or phosphonium cation, and it is even more preferable to use a pyrrolidinium cation, imidazolium cation, or phosphonium cation in terms of the effects of the present invention.

Specific examples of the alkyl chain quaternary ammonium cation include quaternary ammonium cations represented by the following formula (L1): tetramethylammonium cation, ethyltrimethylammonium cation, diethyldimethylammonium cation, triethylmethylammonium cation, tetraethylammonium cation, octyltrimethylammonium cation, hexyltrimethylammonium cation, methyltrioctylammonium cation, etc.
Specific examples of the piperidinium cation include the piperidinium cation represented by the following formula (L2). Specific examples include 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, and 1,1-dibutylpiperidinium cation.
Specific examples of the pyrimidinium cation include 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation, and the like.

Specific examples of the pyrrolidinium cation include pyrrolidinium cations represented by the following formula (L3). More specific examples include 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, and 1,1-dibutylpyrrolidinium cation.
Specific examples of the imidazolium cation include imidazolium cations represented by the following formula (L5). More specific examples include 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, and 1-hexyl-2,3-dimethylimidazolium cation.
Specific examples of the pyridinium cation include pyridinium cations represented by the following formula (L6), and more specific examples include 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, and 1-butyl-3,4-dimethylpyridinium cation.

Specific examples of the pyrazonium cation include, for example, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation, and the like.

Specific examples of the phosphonium cation include phosphonium cations represented by the following formula (L4): Specific examples include tetraalkylphosphonium cations such as tetrabutylphosphonium cation, tributylmethylphosphonium cation, and tributylhexylphosphonium cation, and triethyl(methoxymethyl)phosphonium cation.
Specific examples of the sulfonium cation include triethylsulfonium cation, dimethylethylsulfonium cation, triethylsulfonium cation, ethylmethylpropylsulfonium cation, butyldimethylsulfonium cation, 1-methyltetrahydrothiopheniumone, 1-ethyltetrahydrothiophenium cation, 1-propyltetrahydrothiophenium cation, 1-butyltetrahydrothiophenium cation, and 1-methyl-[1,4]-thioxonium cation, etc. Among these, the sulfonium cation is preferably a sulfonium cation having a cyclic structure such as a tetrahydrothiophenium-based or hexahydrothiopyrylium-based 5-membered or 6-membered ring, which may have a heteroatom such as an oxygen atom in the cyclic structure.

In formulas (L1) to (L4), R ^L1 to R ^L4 each independently represent an alkyl group having 1 to 20 carbon atoms, or an alkoxyalkyl group represented by R ^L7 -O-(CH ₂ ) _Ln - (R ^L7 represents a methyl group or an ethyl group, and Ln represents an integer of 1 to 4).
In formula (L5), R ^L1 to R ^L4 each independently represent an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group represented by R ^L7 -O-(CH ₂ ) _Ln - (R ^L7 represents a methyl group or an ethyl group, and Ln represents an integer of 1 to 4), or a hydrogen atom.
In formula (L6), R ^L1 to R ^L6 each independently represent an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group represented by R ^L7 -O-(CH ₂ ) _Ln - (R ^L7 represents a methyl group or an ethyl group, and Ln represents an integer of 1 or more and 4 or less), or a hydrogen atom.

The anion constituting the ionic liquid (B) may be an organic anion or an inorganic anion, but is preferably an organic anion because the ionic liquid (B) has a good affinity with the solvent (S) described below.
The organic anion is preferably at least one selected from the group consisting of a carboxylate anion, an N-acylamino acid ion, an acidic amino acid anion, a neutral amino acid anion, an alkyl sulfate anion, a fluorine-containing compound anion, and a phenol anion, and is more preferably a carboxylate anion or an N-acylamino acid ion.

Specific examples of the carboxylate anion include acetate ion, decanoate ion, 2-pyrrolidone-5-carboxylate ion, formate ion, α-lipoic acid ion, lactate ion, tartrate ion, hippurate ion, and N-methylhippurate ion. Among these, acetate ion, 2-pyrrolidone-5-carboxylate ion, formate ion, lactate ion, tartrate ion, hippurate ion, and N-methylhippurate ion are preferred, and acetate ion, N-methylhippurate ion, and formate ion are more preferred.
Specific examples of the N-acylamino acid ion include an N-benzoylalanine ion, an N-acetylphenylalanine ion, an aspartic acid ion, a glycine ion, and an N-acetylglycine ion. Among these, the N-benzoylalanine ion, the N-acetylphenylalanine ion, and the N-acetylglycine ion are preferred, and the N-acetylglycine ion is more preferred.

Specific examples of the acidic amino acid anion include aspartic acid ion and glutamic acid ion, and specific examples of the neutral amino acid anion include glycine ion, alanine ion, and phenylalanine ion.
Specific examples of the alkyl sulfate anions include a methanesulfonate ion, and specific examples of the fluorine-containing compound anions include a trifluoromethanesulfonate ion, a hexafluorophosphonate ion, a trifluorotris(pentafluoroethyl)phosphonate ion, a bis(fluoroalkylsulfonyl)imide ion (e.g., a bis(trifluoromethanesulfonyl)imide ion), a trifluoroacetate ion, and a tetrafluoroborate ion. Specific examples of the phenol anions include a phenol ion, a 2-methoxyphenol ion, and a 2,6-di-tert-butylphenol ion.

From the viewpoint of more reliably achieving the effects of the present invention, the inorganic anion is preferably at least one selected from the group consisting of F ^- , Cl ^- , Br ^- , I ^- , BF ₄ ^- , PF ₆ ^- and N(SO ₂ F) ₂ ^- , more preferably BF ₄ ^- , PF ₆ ^- or N(SO ₂ F) ₂ ^- , and even more preferably BF ₄ ^- or PF ₆ ^- .

The ionic liquid can be produced, for example, by the method disclosed in paragraph 0045 of WO 2014/178254.
The ionic liquids may be used alone or in combination of two or more kinds.
The content of the ionic liquid is not particularly limited as long as the effects of the present invention can be achieved, but is preferably 0.0001 parts by mass or more and 1 part by mass or less, more preferably 0.001 parts by mass or more and 1 part by mass or less, even more preferably 0.002 parts by mass or more and 0.1 parts by mass or less, and particularly preferably 0.003 parts by mass or more and 0.07 parts by mass or less, relative to 100 parts by mass of the curable compound.

(Cure Accelerator)
The curable composition may contain a curing accelerator. When the curable composition contains a curing accelerator, the curable composition can have a high refractive index and high yellowing resistance, and the curability of the curable composition can be improved to form a metal oxide-containing film having particularly good heat resistance (resistance to thermal decomposition) and adhesion to a substrate.

Examples of hardening accelerators include urea compounds, tertiary amines and their salts, imidazoles and their salts, phosphine compounds and their derivatives, metal carboxylates, Lewis acids, Bronsted acids and their salts, and tetraphenylboron salts.

Specific examples of preferred curing accelerators include tertiary amines such as 1,8-diazabicyclo(5,4,0)undecene-7, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine; tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate, and tetraphenylboron salts of N-methylmorpholine tetraphenylborate.

Among the curing accelerators described above, phosphine compounds and their derivatives, and tetraphenylboron salts are preferred. Among the specific examples above, triphenylphosphine and triphenylphosphinetriphenylborane are preferred.

The amount of the curing accelerator used is not particularly limited as long as it does not impair the object of the present invention. The amount of the curing accelerator used is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 2 parts by mass or less, relative to 100 parts by mass of the curable compound.

(Sensitizer)
The curable composition may contain a sensitizer. When the curable composition contains a cationic polymerization initiator, and the cationic polymerization initiator contains a sulfonium cation and/or an iodonium cation, the curable composition preferably contains a sensitizer. As the sensitizer, any known sensitizer that has been used in combination with various cationic polymerization initiators in the past can be used without any particular limitation.
Suitable examples of the sensitizer are the same as those described for the energy-sensitive composition of the fifth embodiment. Two or more types of sensitizers may be used in combination.

The amount of sensitizer used is not particularly limited, but is preferably 1% by mass or more and 300% by mass or less, and more preferably 5% by mass or more and 200% by mass or less, relative to the mass of the cationic polymerization initiator. By using an amount of sensitizer within this range, it is easy to obtain the desired sensitization effect.

(Antioxidant)
The curable composition may or may not contain an antioxidant, but from the viewpoint of yellowing resistance, it preferably contains an antioxidant.
Examples of the antioxidant include phenol compounds, phosphite compounds, and thioether compounds, and more preferably phenol compounds having a molecular weight of 500 or more, phosphite compounds having a molecular weight of 500 or more, or thioether compounds having a molecular weight of 500 or more. The antioxidant is preferably a phenol compound, and more preferably a phenol compound having a molecular weight of 500 or more.

As the phenolic compound, any phenolic compound known as a phenolic coloring inhibitor can be used. A preferred phenolic compound is a hindered phenolic compound. In particular, a compound having a substituent at the site (ortho position) adjacent to the phenolic hydroxyl group is preferred. As the aforementioned substituent, a substituted or unsubstituted alkyl group having 1 to 22 carbon atoms is preferred, and a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a tert-pentyl group, a hexyl group, an octyl group, an isooctyl group, or a 2-ethylhexyl group is more preferred. Also preferred are compounds having a phenolic group and a phosphite ester group in the same molecule.

The phosphite ester compound may be at least one compound selected from the group consisting of tris[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine, tris[2-[(4,6,9,11-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-2-yl)oxy]ethyl]amine, and ethyl bis(2,4-ditert-butyl-6-methylphenyl)phosphite.

Antioxidants are readily available as commercial products, and examples include ADK STAB AO-20, ADK STAB AO-30, ADK STAB AO-40, ADK STAB AO-50, ADK STAB AO-50F, ADK STAB AO-60, ADK STAB AO-60G, ADK STAB AO-80, ADK STAB AO-330, ADK STAB PEP-36A, and ADK STAB AO-412S (ADEKA CORPORATION).

The content of the antioxidant is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.3% by mass or more and 15% by mass or less, of the components of the curable composition excluding the solvent. The coloring inhibitor may be one type or two or more types. When two or more types are used, it is preferable that the total amount is within the above range.

(Other ingredients)
The curable composition may contain additives such as surfactants, thermal polymerization inhibitors, defoamers, silane coupling agents, colorants (pigments, dyes), resins (thermoplastic resins, alkali-soluble resins, etc.), organic fillers, etc. Any of the additives may be any of those known in the art.

(solvent)
The curable composition preferably contains a solvent for the purpose of adjusting the coating property and viscosity. As the solvent, an organic solvent is typically used. The type of the organic solvent is not particularly limited as long as it can uniformly dissolve or disperse the components contained in the curable composition.

Suitable examples of organic solvents that can be used as the solvent are the same as the suitable examples of organic solvents in the energy-sensitive composition of the first embodiment.

The amount of the solvent used in the curable composition is not particularly limited. In terms of the coatability of the curable composition, the amount of the solvent used is, for example, 30% by mass or more and 99.9% by mass or less, and preferably 50% by mass or more and 98% by mass or less, based on the entire curable composition.

(Metal oxide-containing film)
The metal oxide-containing film obtained by curing the curable composition as the energy-sensitive composition of the sixth embodiment described above has excellent refractive index and yellowing resistance, and also has heat resistance and adhesion to a substrate. is also good.
The thickness of the cured film is not particularly limited, but is preferably from 10 nm to 50 μm, more preferably from 50 nm to 30 μm, even more preferably from 100 nm to 10 μm, and still more preferably from 300 nm to 5 μm. It is particularly preferred that:
The cured film can be used in, for example, sealing materials for OLED display elements, OLED lighting, hard coats, insulating films, anti-reflection films, interlayer insulating films, carbon hard masks, display panel materials (planarizing films, color filter pixels, organic It is suitable for various applications such as EL partitions, spacers), optical members (lenses, microlenses, wafer level lenses, optical fibers, optical waveguides, prism sheets, holograms, high refractive index films, and retroreflective films). The film has excellent flexibility and is not easily broken, making it suitable for use in flexible display panels and flexible lighting.
Furthermore, the cured film is particularly preferably used as a transparent coating for covering metal wiring and the like in display elements such as touch panels.

(7) Silicon-containing resin composition As mentioned above, resins that form a cured film by baking are also preferred as precursor resins for the substrate component (B). Examples of resins that form a cured film by baking include silicon-containing resins. Preferred examples of silicon-containing resins include one or more selected from siloxane resins and polysilanes. A metal oxide-containing film containing a silicon-containing resin is obtained by applying a metal oxide fine particle dispersion liquid containing these silicon-containing resins. A silica-based metal oxide-containing film is obtained by baking the metal oxide-containing film.
The siloxane resin and polysilane will be described below.

(Siloxane resin)
There are no particular limitations on the siloxane resin, so long as it is a resin that is soluble in the solvent described below.
As the siloxane resin, for example, a siloxane resin obtained by hydrolysis and condensation of at least one silane compound selected from those represented by the following formula (Ca) is preferably used.
R ^Y0 _(4-n0) Si(OR') _n0 ...(C-a)

In formula (C-a), R ^Y0 represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, R' represents an alkyl group or a phenyl group, and n0 represents an integer of 2 to 4. When multiple R ^Y0 are bonded to Si, the multiple R ^Y0 may be the same or different. In addition, multiple (OR') groups bonded to Si may be the same or different.

The alkyl group represented by R ^Y0 is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

When R ^Y0 is an aryl group or an aralkyl group, the aryl group contained in these groups is not particularly limited as long as it does not impair the object of the present invention. Suitable examples of the aryl group include the following groups.

Among the groups of the above formula, the groups of the following formula are preferred:

In the above formula, R ^a1 is a hydrogen atom, a hydroxyl group, an alkoxy group such as a methoxy group, an ethoxy group, a butoxy group, a propoxy group, etc., or a hydrocarbon group such as a methyl group, an ethyl group, a butyl group, a propyl group, etc. In the above formula, R ^a2 is an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, etc.

When R ^Y0 is an aryl group or an aralkyl group, specific preferred examples include a benzyl group, a phenethyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a biphenylyl group, a fluorenyl group, and a pyrenyl group.

The number of benzene rings contained in the aryl group or aralkyl group is preferably 1 to 3. When the number of benzene rings is 1 to 3, the manufacturability of the siloxane resin is good, and the increase in the degree of polymerization of the siloxane resin suppresses volatilization during firing, making it easy to form a silica film. The aryl group or aralkyl group may have a hydroxyl group as a substituent.

The alkyl group represented by R' is preferably a linear or branched alkyl group having from 1 to 5 carbon atoms. The number of carbon atoms in the alkyl group represented by R' is preferably 1 or 2, particularly from the viewpoint of hydrolysis rate.
When n0 in formula (Ca) is 4, the silane compound (i) is represented by the following formula (Cb).
Si(OR ^Y1 ) _a1 (OR ^Y2 ) _b1 (OR ^Y3 ) _c1 (OR ^Y4 ) _d1 ...(Cb)

In formula (Cb), R ^Y1 , R ^Y2 , R ^Y3 and R ^Y4 each independently represent the same alkyl group or phenyl group as R′ above.

a1, b1, c1, and d1 are integers that satisfy the conditions 0≦a1≦4, 0≦b1≦4, 0≦c1≦4, and 0≦d1≦4, and a1+b1+c1+d1=4.

When n0 in formula (Ca) is 3, the silane compound (ii) is represented by the following formula (Cc).
R ^Y5 Si(OR ^Y6 ) _e1 (OR ^Y7 ) _f1 (OR ^Y8 ) _g1 ...(C-c)

In formula (Cc), R ^Y5 represents a hydrogen atom, or the same alkyl group, aryl group, or aralkyl group as R. R ^Y6 , R ^Y7 , and R ^Y8 each independently represent the same alkyl group or phenyl group as R′.

e1, f1, and g1 are integers that satisfy the conditions 0≦e1≦3, 0≦f1≦3, and 0≦g1≦3, and that e1+f1+g1=3.

When n0 in formula (Ca) is 2, the silane compound (iii) is represented by the following formula (Cd).
^{RY9 RY10} Si(OR ^Y11 ) _h1 (OR ^Y12 ) _i1 ...(Cd)

In formula (Cd), R ^Y9 and R ^Y10 each represent a hydrogen atom, the same alkyl group, aryl group, or aralkyl group as R above. R ^Y11 and R ^Y12 each independently represent the same alkyl group or phenyl group as R′ above.

h1 and i1 are integers that satisfy the conditions 0≦h1≦2, 0≦i1≦2, and h1+i1=2.

Specific examples of silane compounds (i) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetrapentyloxysilane, tetraphenyloxysilane, trimethoxymonoethoxysilane, dimethoxydiethoxysilane, triethoxymonomethoxysilane, trimethoxymonopropoxysilane, monomethoxytributoxysilane, monomethoxytripentyloxysilane, monomethoxytriphenyloxysilane, dimethoxydipropoxysilane, tripropoxymonomethoxysilane, trimethoxymonobutoxysilane, dimethoxydibutoxysilane, and triethoxymonopropoxysilane. Examples of tetraalkoxysilanes include tetraalkoxysilanes such as diethoxydipropoxysilane, tributoxymonopropoxysilane, dimethoxymonoethoxymonobutoxysilane, diethoxymonomethoxymonobutoxysilane, diethoxymonopropoxymonobutoxysilane, dipropoxymonomethoxymonoethoxysilane, dipropoxymonomethoxymonobutoxysilane, dipropoxymonoethoxymonobutoxysilane, dibutoxymonomethoxymonoethoxysilane, dibutoxymonoethoxymonopropoxysilane, and monomethoxymonoethoxymonopropoxymonobutoxysilane, and among these, tetramethoxysilane and tetraethoxysilane are preferred.

Specific examples of the silane compound (ii) include:
hydrosilane compounds such as trimethoxysilane, triethoxysilane, tripropoxysilane, tripentyloxysilane, triphenyloxysilane, dimethoxymonoethoxysilane, diethoxymonomethoxysilane, dipropoxymonomethoxysilane, dipropoxymonoethoxysilane, dipentyloxylmonomethoxysilane, dipentyloxymonoethoxysilane, dipentyloxymonopropoxysilane, diphenyloxylmonomethoxysilane, diphenyloxymonoethoxysilane, diphenyloxymonopropoxysilane, methoxyethoxypropoxysilane, monopropoxydimethoxysilane, monopropoxydiethoxysilane, monobutoxydimethoxysilane, monopentyloxydiethoxysilane, and monophenyloxydiethoxysilane;
Methylsilane compounds such as methyltrimethoxysilane, methyltriethoxysilane, methyltrippropoxysilane, methyltripentyloxysilane, methyltriphenyloxysilane, methylmonomethoxydiethoxysilane, methylmonomethoxydipropoxysilane, methylmonomethoxydipentyloxysilane, methylmonomethoxydiphenyloxysilane, methylmethoxyethoxypropoxysilane, and methylmonomethoxymonoethoxymonobutoxysilane;
ethylsilane compounds such as ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrippropoxysilane, ethyltripentyloxysilane, ethyltriphenyloxysilane, ethylmonomethoxydiethoxysilane, ethylmonomethoxydipropoxysilane, ethylmonomethoxydipentyloxysilane, ethylmonomethoxydiphenyloxysilane, ethylmethoxyethoxypropoxysilane, and ethylmonomethoxymonoethoxymonobutoxysilane;
Propyl silane compounds such as propyl trimethoxy silane, propyl triethoxy silane, propyl tripropoxy silane, propyl tripentyloxy silane, and propyl triphenyloxy silane, propyl monomethoxy diethoxy silane, propyl monomethoxy dipropoxy silane, propyl monomethoxy dipentyloxy silane, propyl monomethoxy diphenyloxy silane, propyl methoxy ethoxy propoxy silane, and propyl monomethoxy monoethoxy monobutoxy silane;
butyl silane compounds such as butyl trimethoxy silane, butyl triethoxy silane, butyl tripropoxy silane, butyl tripentyloxy silane, butyl triphenyloxy silane, butyl monomethoxy diethoxy silane, butyl monomethoxy dipropoxy silane, butyl monomethoxy dipentyloxy silane, butyl monomethoxy diphenyloxy silane, butyl methoxy ethoxy propoxy silane, and butyl monomethoxy monoethoxy monobutoxy silane;
Phenylsilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrippropoxysilane, phenyltripentyloxysilane, phenyltriphenyloxysilane, phenylmonomethoxydiethoxysilane, phenylmonomethoxydipropoxysilane, phenylmonomethoxydipentyloxysilane, phenylmonomethoxydiphenyloxysilane, phenylmethoxyethoxypropoxysilane, trimethoxy(2-phenylethyl)silane, and phenylmonomethoxymonoethoxymonobutoxysilane;
hydroxyphenylsilane compounds such as hydroxyphenyltrimethoxysilane, hydroxyphenyltriethoxysilane, hydroxyphenyltripropoxysilane, hydroxyphenyltripentyloxysilane, hydroxyphenyltriphenyloxysilane, hydroxyphenylmonomethoxydiethoxysilane, hydroxyphenylmonomethoxydipropoxysilane, hydroxyphenylmonomethoxydipentyloxysilane, hydroxyphenylmonomethoxydiphenyloxysilane, hydroxyphenylmethoxyethoxypropoxysilane, and hydroxyphenylmonomethoxymonoethoxymonobutoxysilane;
naphthylsilane compounds such as naphthyltrimethoxysilane, naphthyltriethoxysilane, naphthyltripropoxysilane, naphthyltripentyloxysilane, naphthyltriphenyloxysilane, naphthylmonomethoxydiethoxysilane, naphthylmonomethoxydipropoxysilane, naphthylmonomethoxydipentyloxysilane, naphthylmonomethoxydiphenyloxysilane, naphthylmethoxyethoxypropoxysilane, and naphthylmonomethoxymonoethoxymonobutoxysilane;
benzyl silane compounds such as benzyl trimethoxy silane, benzyl triethoxy silane, benzyl tripropoxy silane, benzyl tripentyloxy silane, benzyl triphenyloxy silane, benzyl monomethoxy diethoxy silane, benzyl monomethoxy dipropoxy silane, benzyl monomethoxy dipentyloxy silane, benzyl monomethoxy diphenyloxy silane, benzyl methoxy ethoxy propoxy silane, and benzyl monomethoxy monoethoxy monobutoxy silane;
hydroxybenzyl silane compounds such as hydroxybenzyl trimethoxysilane, hydroxybenzyl triethoxysilane, hydroxybenzyl tripropoxysilane, hydroxybenzyl tripentyloxysilane, hydroxybenzyl triphenyloxysilane, hydroxybenzyl monomethoxy diethoxysilane, hydroxybenzyl monomethoxy dipropoxysilane, hydroxybenzyl monomethoxy dipentyloxysilane, hydroxybenzyl monomethoxy diphenyloxysilane, hydroxybenzyl methoxyethoxypropoxysilane, and hydroxybenzyl monomethoxy monoethoxy monobutoxysilane;
Examples include:

Specific examples of the silane compound (iii) include:
hydrosilane compounds such as dimethoxysilane, diethoxysilane, dipropoxysilane, dipentyloxysilane, diphenyloxysilane, methoxyethoxysilane, methoxypropoxysilane, methoxypentyloxysilane, methoxyphenyloxysilane, ethoxypropoxysilane, ethoxypentyloxysilane, and ethoxyphenyloxysilane;
Methylhydrosilane compounds such as methyldimethoxysilane, methylmethoxyethoxysilane, methyldiethoxysilane, methylmethoxypropoxysilane, methylmethoxypentyloxysilane, methylethoxypropoxysilane, methyldipropoxysilane, methyldipentyloxysilane, methyldiphenyloxysilane, and methylmethoxyphenyloxysilane;
Ethylhydrosilane compounds such as ethyldimethoxysilane, ethylmethoxyethoxysilane, ethyldiethoxysilane, ethylmethoxypropoxysilane, ethylmethoxypentyloxysilane, ethylethoxypropoxysilane, ethyldipropoxysilane, ethyldipentyloxysilane, ethyldiphenyloxysilane, and ethylmethoxyphenyloxysilane;
propylhydrosilane compounds such as propyldimethoxysilane, propylmethoxyethoxysilane, propyldiethoxysilane, propylmethoxypropoxysilane, propylmethoxypentyloxysilane, propylethoxypropoxysilane, propyldipropoxysilane, propyldipentyloxysilane, propyldiphenyloxysilane, and propylmethoxyphenyloxysilane;
butylhydrosilane compounds such as butyldimethoxysilane, butylmethoxyethoxysilane, butyldiethoxysilane, butylmethoxypropoxysilane, butylmethoxypentyloxysilane, butylethoxypropoxysilane, butyldipropoxysilane, butyldipentyloxysilane, butyldiphenyloxysilane, and butylmethoxyphenyloxysilane;
Phenylhydrosilane compounds such as phenyldimethoxysilane, phenylmethoxyethoxysilane, phenyldiethoxysilane, phenylmethoxypropoxysilane, phenylmethoxypentyloxysilane, phenylethoxypropoxysilane, phenyldipropoxysilane, phenyldipentyloxysilane, phenyldiphenyloxysilane, and phenylmethoxyphenyloxysilane;
hydroxyphenyl hydrosilane compounds such as hydroxyphenyl dimethoxysilane, hydroxyphenyl methoxyethoxysilane, hydroxyphenyl diethoxysilane, hydroxyphenyl methoxypropoxysilane, hydroxyphenyl methoxypentyloxysilane, hydroxyphenyl ethoxypropoxysilane, hydroxyphenyl dipropoxysilane, hydroxyphenyl dipentyloxysilane, hydroxyphenyl diphenyloxysilane, and hydroxyphenyl methoxyphenyloxysilane;
naphthylhydrosilane compounds such as naphthyldimethoxysilane, naphthylmethoxyethoxysilane, naphthyldiethoxysilane, naphthylmethoxypropoxysilane, naphthylmethoxypentyloxysilane, naphthylethoxypropoxysilane, naphthyldipropoxysilane, naphthyldipentyloxysilane, naphthyldiphenyloxysilane, and naphthylmethoxyphenyloxysilane;
benzyl hydrosilane compounds such as benzyl dimethoxysilane, benzyl methoxyethoxysilane, benzyl diethoxysilane, benzyl methoxypropoxysilane, benzyl methoxypentyloxysilane, benzyl ethoxypropoxysilane, benzyl dipropoxysilane, benzyl dipentyloxysilane, benzyl diphenyloxysilane, and benzyl methoxyphenyloxysilane;
hydroxybenzyl hydrosilane compounds such as hydroxybenzyl dimethoxysilane, hydroxybenzyl methoxyethoxysilane, hydroxybenzyl diethoxysilane, hydroxybenzyl methoxypropoxysilane, hydroxybenzyl methoxypentyloxysilane, hydroxybenzyl ethoxypropoxysilane, hydroxybenzyl dipropoxysilane, hydroxybenzyl dipentyloxysilane, hydroxybenzyl diphenyloxysilane, and hydroxybenzyl methoxyphenyloxysilane;
dimethylsilane compounds such as dimethyldimethoxysilane, dimethylmethoxyethoxysilane, dimethylmethoxypropoxysilane, dimethyldiethoxysilane, dimethyldipentyloxysilane, dimethyldiphenyloxysilane, dimethylethoxypropoxysilane, and dimethyldipropoxysilane;
diethylsilane compounds such as diethyldimethoxysilane, diethylmethoxyethoxysilane, diethylmethoxypropoxysilane, diethyldiethoxysilane, diethyldipentyloxysilane, diethyldiphenyloxysilane, diethylethoxypropoxysilane, and diethyldipropoxysilane;
dipropoxysilane compounds such as dipropyldimethoxysilane, dipropylmethoxyethoxysilane, dipropylmethoxypropoxysilane, dipropyldiethoxysilane, dipropyldipentyloxysilane, dipropyldiphenyloxysilane, dipropylethoxypropoxysilane, and dipropyldipropoxysilane;
dibutylsilane compounds such as dibutyldimethoxysilane, dibutylmethoxyethoxysilane, dibutylmethoxypropoxysilane, dibutyldiethoxysilane, dibutyldipentyloxysilane, dibutyldiphenyloxysilane, dibutylethoxypropoxysilane, and dibutyldipropoxysilane;
diphenylsilane compounds such as diphenyldimethoxysilane, diphenylmethoxyethoxysilane, diphenylmethoxypropoxysilane, diphenyldiethoxysilane, diphenyldipentyloxysilane, diphenyldiphenyloxysilane, diphenylethoxypropoxysilane, and diphenyldipropoxysilane;
di(hydroxyphenyl)silane compounds such as di(hydroxyphenyl)dimethoxysilane, di(hydroxyphenyl)methoxyethoxysilane, di(hydroxyphenyl)methoxypropoxysilane, di(hydroxyphenyl)diethoxysilane, di(hydroxyphenyl)dipentyloxysilane, di(hydroxyphenyl)diphenyloxysilane, di(hydroxyphenyl)ethoxypropoxysilane, and di(hydroxyphenyl)dipropoxysilane;
dinaphthylsilane compounds such as dinaphthyl dimethoxysilane, dinaphthyl methoxyethoxysilane, dinaphthyl methoxypropoxysilane, dinaphthyl diethoxysilane, dinaphthyl dipentyloxysilane, dinaphthyl diphenyloxysilane, dinaphthyl ethoxypropoxysilane, and dinaphthyl dipropoxysilane;
dibenzylsilane compounds such as dibenzyldimethoxysilane, dibenzylmethoxyethoxysilane, dibenzylmethoxypropoxysilane, dibenzyldiethoxysilane, dibenzyldipentyloxysilane, dibenzyldiphenyloxysilane, dibenzylethoxypropoxysilane, and dibenzyldipropoxysilane;
di(hydroxybenzyl)silane compounds such as di(hydroxybenzyl)dimethoxysilane, di(hydroxybenzyl)methoxyethoxysilane, di(hydroxybenzyl)methoxypropoxysilane, di(hydroxybenzyl)diethoxysilane, di(hydroxybenzyl)dipentyloxysilane, di(hydroxybenzyl)diphenyloxysilane, di(hydroxybenzyl)ethoxypropoxysilane, and di(hydroxybenzyl)dipropoxysilane;
methylethylsilane compounds such as methylethyldimethoxysilane, methylethylmethoxyethoxysilane, methylethylmethoxypropoxysilane, methylethyldiethoxysilane, methylethyldipentyloxysilane, methylethyldiphenyloxysilane, methylethylethoxypropoxysilane, and methylethyldipropoxysilane;
methylpropylsilane compounds such as methylpropyldimethoxysilane, methylpropylmethoxyethoxysilane, methylpropylmethoxypropoxysilane, methylpropyldiethoxysilane, methylpropyldipentyloxysilane, methylpropyldiphenyloxysilane, methylpropylethoxypropoxysilane, and methylpropyldipropoxysilane;
methylbutylsilane compounds such as methylbutyldimethoxysilane, methylbutylmethoxyethoxysilane, methylbutylmethoxypropoxysilane, methylbutyldiethoxysilane, methylbutyldipentyloxysilane, methylbutyldiphenyloxysilane, methylbutylethoxypropoxysilane, and methylbutyldipropoxysilane;
Methyl(phenyl)silane compounds such as methyl(phenyl)dimethoxysilane, methyl(phenyl)methoxyethoxysilane, methyl(phenyl)methoxypropoxysilane, methyl(phenyl)diethoxysilane, methyl(phenyl)dipentyloxysilane, methyl(phenyl)diphenyloxysilane, methyl(phenyl)ethoxypropoxysilane, and methyl(phenyl)dipropoxysilane;
methyl(hydroxyphenyl)silane compounds such as methyl(hydroxyphenyl)dimethoxysilane, methyl(hydroxyphenyl)methoxyethoxysilane, methyl(hydroxyphenyl)methoxypropoxysilane, methyl(hydroxyphenyl)diethoxysilane, methyl(hydroxyphenyl)dipentyloxysilane, methyl(hydroxyphenyl)diphenyloxysilane, methyl(hydroxyphenyl)ethoxypropoxysilane, and methyl(hydroxyphenyl)dipropoxysilane;
methyl(naphthyl)silane compounds such as methyl(naphthyl)dimethoxysilane, methyl(naphthyl)methoxyethoxysilane, methyl(naphthyl)methoxypropoxysilane, methyl(naphthyl)diethoxysilane, methyl(naphthyl)dipentyloxysilane, methyl(naphthyl)diphenyloxysilane, methyl(naphthyl)ethoxypropoxysilane, and methyl(naphthyl)dipropoxysilane;
methyl(benzyl)silane compounds such as methyl(benzyl)dimethoxysilane, methyl(benzyl)methoxyethoxysilane, methyl(benzyl)methoxypropoxysilane, methyl(benzyl)diethoxysilane, methyl(benzyl)dipentyloxysilane, methyl(benzyl)diphenyloxysilane, methyl(benzyl)ethoxypropoxysilane, and methyl(benzyl)dipropoxysilane;
methyl(hydroxybenzyl)silane compounds such as methyl(hydroxybenzyl)dimethoxysilane, methyl(hydroxybenzyl)methoxyethoxysilane, methyl(hydroxybenzyl)methoxypropoxysilane, methyl(hydroxybenzyl)diethoxysilane, methyl(hydroxybenzyl)dipentyloxysilane, methyl(hydroxybenzyl)diphenyloxysilane, methyl(hydroxybenzyl)ethoxypropoxysilane, and methyl(hydroxybenzyl)dipropoxysilane;
Ethylpropyl silane compounds such as ethylpropyl dimethoxysilane, ethylpropyl methoxyethoxysilane, ethylpropyl methoxypropoxysilane, ethylpropyl diethoxysilane, ethylpropyl dipentyloxysilane, ethylpropyl diphenyloxysilane, ethylpropyl ethoxypropoxysilane, and ethylpropyl dipropoxysilane;
ethylbutylsilane compounds such as ethylbutyldimethoxysilane, ethylbutylmethoxyethoxysilane, ethylbutylmethoxypropoxysilane, ethylbutyldiethoxysilane, ethylbutyldipentyloxysilane, ethylbutyldiphenyloxysilane, ethylbutylethoxypropoxysilane, and ethylbutyldipropoxysilane;
Ethyl(phenyl)silane compounds such as ethyl(phenyl)dimethoxysilane, ethyl(phenyl)methoxyethoxysilane, ethyl(phenyl)methoxypropoxysilane, ethyl(phenyl)diethoxysilane, ethyl(phenyl)dipentyloxysilane, ethyl(phenyl)diphenyloxysilane, ethyl(phenyl)ethoxypropoxysilane, and ethyl(phenyl)dipropoxysilane;
ethyl(hydroxyphenyl)silane compounds such as ethyl(hydroxyphenyl)dimethoxysilane, ethyl(hydroxyphenyl)methoxyethoxysilane, ethyl(hydroxyphenyl)methoxypropoxysilane, ethyl(hydroxyphenyl)diethoxysilane, ethyl(hydroxyphenyl)dipentyloxysilane, ethyl(hydroxyphenyl)diphenyloxysilane, ethyl(hydroxyphenyl)ethoxypropoxysilane, and ethyl(hydroxyphenyl)dipropoxysilane;
ethyl(naphthyl)silane compounds such as ethyl(naphthyl)dimethoxysilane, ethyl(naphthyl)methoxyethoxysilane, ethyl(naphthyl)methoxypropoxysilane, ethyl(naphthyl)diethoxysilane, ethyl(naphthyl)dipentyloxysilane, ethyl(naphthyl)diphenyloxysilane, ethyl(naphthyl)ethoxypropoxysilane, and ethyl(naphthyl)dipropoxysilane;
ethyl(benzyl)silane compounds such as ethyl(benzyl)dimethoxysilane, ethyl(benzyl)methoxyethoxysilane, ethyl(benzyl)methoxypropoxysilane, ethyl(benzyl)diethoxysilane, ethyl(benzyl)dipentyloxysilane, ethyl(benzyl)diphenyloxysilane, ethyl(benzyl)ethoxypropoxysilane, and ethyl(benzyl)dipropoxysilane;
ethyl(hydroxybenzyl)silane compounds such as ethyl(hydroxybenzyl)dimethoxysilane, ethyl(hydroxybenzyl)methoxyethoxysilane, ethyl(hydroxybenzyl)methoxypropoxysilane, ethyl(hydroxybenzyl)diethoxysilane, ethyl(hydroxybenzyl)dipentyloxysilane, ethyl(hydroxybenzyl)diphenyloxysilane, ethyl(hydroxybenzyl)ethoxypropoxysilane, and ethyl(hydroxybenzyl)dipropoxysilane;
Propylbutylsilane compounds such as propylbutyldimethoxysilane, propylbutylmethoxyethoxysilane, propylbutylmethoxypropoxysilane, propylbutyldiethoxysilane, propylbutyldipentyloxysilane, propylbutyldiphenyloxysilane, propylbutylethoxypropoxysilane, and propylbutyldipropoxysilane;
Propyl(phenyl)silane compounds such as propyl(phenyl)dimethoxysilane, propyl(phenyl)methoxyethoxysilane, propyl(phenyl)methoxypropoxysilane, propyl(phenyl)diethoxysilane, propyl(phenyl)dipentyloxysilane, propyl(phenyl)diphenyloxysilane, propyl(phenyl)ethoxypropoxysilane, and propyl(phenyl)dipropoxysilane;
Propyl(hydroxyphenyl)silane compounds such as propyl(hydroxyphenyl)dimethoxysilane, propyl(hydroxyphenyl)methoxyethoxysilane, propyl(hydroxyphenyl)methoxypropoxysilane, propyl(hydroxyphenyl)diethoxysilane, propyl(hydroxyphenyl)dipentyloxysilane, propyl(hydroxyphenyl)diphenyloxysilane, propyl(hydroxyphenyl)ethoxypropoxysilane, and propyl(hydroxyphenyl)dipropoxysilane;
Propyl(naphthyl)silane compounds such as propyl(naphthyl)dimethoxysilane, propyl(naphthyl)methoxyethoxysilane, propyl(naphthyl)methoxypropoxysilane, propyl(naphthyl)diethoxysilane, propyl(naphthyl)dipentyloxysilane, propyl(naphthyl)diphenyloxysilane, propyl(naphthyl)ethoxypropoxysilane, and propyl(naphthyl)dipropoxysilane;
Propyl(benzyl)silane compounds such as propyl(benzyl)dimethoxysilane, propyl(benzyl)methoxyethoxysilane, propyl(benzyl)methoxypropoxysilane, propyl(benzyl)diethoxysilane, propyl(benzyl)dipentyloxysilane, propyl(benzyl)diphenyloxysilane, propyl(benzyl)ethoxypropoxysilane, and propyl(benzyl)dipropoxysilane;
Propyl(hydroxybenzyl)silane compounds such as propyl(hydroxybenzyl)dimethoxysilane, propyl(hydroxybenzyl)methoxyethoxysilane, propyl(hydroxybenzyl)methoxypropoxysilane, propyl(hydroxybenzyl)diethoxysilane, propyl(hydroxybenzyl)dipentyloxysilane, propyl(hydroxybenzyl)diphenyloxysilane, propyl(hydroxybenzyl)ethoxypropoxysilane, and propyl(hydroxybenzyl)dipropoxysilane;
Examples include:

The silane compound described above can be subjected to hydrolysis and condensation in a conventional manner to obtain a siloxane resin.
The mass average molecular weight of the siloxane resin is preferably 300 to 30,000, more preferably 500 to 10,000. Two or more siloxane resins having different mass average molecular weights may be mixed. When the mass average molecular weight of the siloxane resin is within this range, it is easy to obtain a metal oxide microparticle dispersion liquid that has excellent film-forming properties and can form a flat metal oxide-containing film.

（式（Ｃ－１－ａ）中、Ｒ^Ｚ１はアルキル基、アリール基、又はアラルキル基であり、Ｒ^Ｚ２は水素又はアルキル基、アリール基、又はアラルキル基であり、ｍ０は０又は１である。） A suitable example of the siloxane resin obtained by hydrolysis and condensation of the silane compound described above is a siloxane resin having a structural unit represented by the following formula (C-1-1). In this siloxane resin, the number of carbon atoms per silicon atom is 2 or more.

(In formula (C-1-a), R ^Z1 is an alkyl group, an aryl group, or an aralkyl group, R ^Z2 is a hydrogen atom or an alkyl group, an aryl group, or an aralkyl group, and m0 is 0 or 1.)

The alkyl group, aryl group, or aralkyl group in R ^{1 Z1} and R 2 ^Z2 are the same as the alkyl group, aryl group, or aralkyl group in the above formula (Ca).
As described above, by using a siloxane resin having an alkyl group, an aryl group, or an aralkyl group, a silica-based metal oxide-containing film having excellent durability can be formed, and a metal oxide microparticle dispersion liquid that can be easily filled into small spaces can be easily obtained.

The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, etc. By having an alkyl group having 1 to 5 carbon atoms, it is easy to form a silica film having good heat resistance.
Examples of the aryl group and the aralkyl group include a benzyl group, a phenethyl group, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a biphenyl group, a fluorenyl group, and a pyrenyl group.

Specific preferred aryl and aralkyl groups include those having the following structures:

In the above formula, R ^Z3 is a hydrogen atom, a hydroxyl group, an alkoxy group such as a methoxy group, an ethoxy group, a butoxy group, a propoxy group, or the like, or a hydrocarbon group such as a methyl group, an ethyl group, a butyl group, a propyl group, or the like, and R ^Z4 is an alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, or the like. Note that the aromatic hydrocarbon group may have a plurality of R ^Z3s as long as at least one aromatic ring in the aromatic hydrocarbon group is included in the aromatic hydrocarbon group. When a plurality of R ^Z3s are included, these R ^Z3s may be the same or different.

Particularly preferred R ^Z1 is a group having the following structure (R ¹ -a) or structure (R ¹ -b), with (R ¹ -b) being particularly preferred.

In formula (C-1-a), m0 is preferably 0, in which case the siloxane resin has a silsesquioxane skeleton. Furthermore, it is more preferable that the siloxane resin is a ladder-type silsesquioxane.

Furthermore, in the structural unit (unit skeleton) represented by formula (C-1-a), it is preferable that the atomic ratio is 2 to 15 carbon atoms per silicon atom.

The siloxane resin may have two or more types of structural units represented by formula (C-1-a). Also, the siloxane resin may be a mixture of siloxane resins having different structural units.
Specific examples of the siloxane resin having two or more types of structural units represented by formula (C-1-a) include siloxane resins represented by the following structural formulas (C-1-1) to (C-1-3).

式（Ｃ－１－４）中、Ｒ^Ｙ１３は、その構造中に（メタ）アクリル基、ビニル基及びエポキシ基からなる群より選ばれる少なくとも１種の基を有する有機基である。（メタ）アクリル基、ビニル基及びエポキシ基からなる群より選ばれる少なくとも１種の基は、Ｓｉ原子に直接結合していてもよく、連結基を介していてもよい。連結基は、例えば、炭素原子数１以上１０以下の直鎖でも分岐鎖であってもよいアルキレン基若しくはアリーレン基、又はこれらを組み合わせた２価の基である。連結基は、エーテル結合、アミノ結合、又はアミド結合を有していてもよい。 The siloxane resin may contain, for example, a structural unit represented by the following formula (C-1-4).

In formula (C-1-4), R ^Y13 is an organic group having at least one group selected from the group consisting of a (meth)acrylic group, a vinyl group, and an epoxy group in its structure. The at least one group selected from the group consisting of a (meth)acrylic group, a vinyl group, and an epoxy group may be bonded directly to a Si atom or via a linking group. The linking group is, for example, an alkylene group or an arylene group having 1 to 10 carbon atoms, which may be linear or branched, or a divalent group combining these. The linking group may have an ether bond, an amino bond, or an amide bond.

Examples of the constitutional unit represented by formula (C-1-4) include, but are not limited to, the units shown below.

Furthermore, when R ^Y13 has an epoxy group, suitable examples of R ^Y13 include a 2-(3,4-epoxycyclohexyl)ethyl group and a 2-(3,4-epoxycyclohexyl)propyl group.

The siloxane resin may contain, for example, a structural unit represented by the following formula (C-1-5).

In formula (C-1-5), R ^Y14 is an organic group having at least one carboxy group in its structure. The carboxy group is preferably bonded to the Si atom via a linking group, and the linking group is, for example, an alkylene group, a cycloalkylene group, or an arylene group, which may be a straight chain or branched chain and has from 1 to 10 carbon atoms, or a divalent group consisting of a combination of these.
The linking group may have an ether bond, an amino bond, an amide bond, or a vinyl bond, and preferably has an amide bond. Examples of R ^Y14 include, but are not limited to, the following. In the following formula, * means the end of the bond of R ^Y14 that bonds to Si in formula (C-1-5).

The metal oxide fine particle dispersion liquid containing the silicon-containing resin as the base component (B) may contain a curing agent described below.
(i) When the curing agent contains a curing agent that generates a base component by exposure to light or heat,
(ii) When the metal oxide fine particle dispersion liquid contains a photopolymerization initiator or a base generator described later, or
(iii) In the case where the method for producing a metal oxide-containing film described later includes an exposure step,
The siloxane resin preferably contains a structural unit represented by formula (C-1-4).
Similarly, when (iv) at least one of the group consisting of photopolymerization initiators, acid generators, or base generators (excluding those corresponding to curing agents) which are other components described below is included, it is preferable that the siloxane resin contains a structural unit represented by formula (C-1-4). The content ratio of the structural unit represented by formula (C-1-4) in the siloxane resin is, for example, 10 mol% or more and 80 mol% or less. As other structural units, it may further contain a structural unit represented by formula (C-1-a) and/or a structural unit represented by formula (C-1-5). In addition, it may contain two or more structural units corresponding to each formula.

In the method for producing a metal oxide-containing film described later, when the method has a development step, the siloxane resin preferably contains one or more structural units selected from the group consisting of structural units represented by formula (C-1-5), structural units having a structure represented by formula (R ¹ -a), and structural units having a structure represented by formula (R ¹ -b). The content ratio of the structural units selected from the group consisting of structural units represented by formula (C-1-5), structural units having a structure represented by formula (R ¹ -a), and structural units having a structure represented by formula (R ¹ -b) in the siloxane resin is, for example, 20 mol% or more and 90 mol% or less. In this case, as other structural units, the structural units represented by formula (C-1-a) and/or structural units represented by formula (C-1-4) may further be contained, and it is preferable that the siloxane resin contains structural units represented by (C-1-4) and structural units represented by (C-1-5). In addition, it may contain two or more structural units corresponding to each formula.

(Polysilane)
The structure of the polysilane is not particularly limited, and may be linear, branched, network, or cyclic, with linear or branched chain structures being preferred.
The polysilane may contain silanol groups and/or alkoxy groups.
Suitable polysilanes include, for example, polysilanes that essentially contain at least one unit represented by the following formulae (A5) and (A6) and optionally contain at least one unit selected from the units represented by the following formulae (A7), (A8) and (A9): Such polysilanes may contain silanol groups or alkoxy groups bonded to silicon atoms.

（式（Ａ５）、（Ａ７）、及び（Ａ８）中、Ｒ^ａ３及びＲ^ａ４は、水素原子、有機基又はシリル基を表す。Ｒ^ａ５は、水素原子又はアルキル基を表す。Ｒ^ａ５がアルキル基である場合、炭素原子数１以上４以下のアルキル基が好ましく、メチル基及びエチル基がより好ましい。）

(In formulae (A5), (A7), and (A8), R ^a3 and R ^a4 represent a hydrogen atom, an organic group, or a silyl group. R ^a5 represents a hydrogen atom or an alkyl group. When R ^a5 represents an alkyl group, it is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.)

With respect to R ^a3 and R ^a4 , examples of the organic group include hydrocarbon groups such as an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group, as well as an alkoxy group, an alkenyloxy group, a cycloalkoxy group, a cycloalkenyloxy group, an aryloxy group, and an aralkyloxy group.
Among these groups, an alkyl group, an aryl group, and an aralkyl group are preferred. Suitable examples of the alkyl group, the aryl group, and the aralkyl group are the same as those in the case where R ^Y0 in the above formula (C-a) is an alkyl group, an aryl group, or an aralkyl group.

（Ａ１０）から（Ａ１３）中、Ｒ^ａ３及びＲ^ａ４は、式（Ａ５）、（Ａ７）、及び（Ａ８）中におけるＲ^ａ３及びＲ^ａ４と同様である。ａ０、ｂ０、及びｃ０は、それぞれ、２以上１，０００以下の整数である。
ａ０、ｂ０、及びｃ０は、それぞれ、１０以上５００以下が好ましく、１０以上１００以下がより好ましい。各ユニット中の構成単位は、ユニット中に、ランダムに含まれていても、ブロック化された状態で含まれていてもよい。 When R ^a3 and R ^a4 are silyl groups, examples of the silyl group include Si _1-10 silanyl groups such as a silyl group, a disilanyl group, and a trisilanyl group (eg, a Si _1-6 silanyl group).
The polysilane preferably contains the following units (A10) to (A13).

In (A10) to (A13), R ^a3 and R ^a4 are the same as R ^a3 and R ^a4 in formulae (A5), (A7), and (A8). a0, b0, and c0 each represent an integer of 2 or more and 1,000 or less.
Each of a0, b0, and c0 is preferably from 10 to 500, and more preferably from 10 to 100. The structural units in each unit may be contained randomly or in a blocked state.

Among the polysilanes described above, polysilanes containing a combination of an alkyl group and an aryl group or an aralkyl group, each of which is bonded to a silicon atom, or polysilanes in which only the alkyl group is bonded to a silicon atom, are preferred. More specifically, polysilanes containing a combination of a methyl group and a benzyl group, each of which is bonded to a silicon atom, polysilanes containing a combination of a methyl group and a phenyl group, each of which is bonded to a silicon atom, or polysilanes in which only the methyl group is bonded to a silicon atom are preferably used.

The mass average molecular weight of the polysilane is preferably 300 to 100,000, more preferably 500 to 70,000, and even more preferably 800 to 30,000. Two or more polysilanes having different mass average molecular weights may be mixed.

The content of the silicon-containing resin in the silicon-containing resin composition as the metal oxide microparticle dispersion is not particularly limited and may be set according to the desired film thickness. From the viewpoint of film-forming properties, the content of the silicon-containing resin in the silicon-containing resin composition is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 40% by mass or less, and particularly preferably 10% by mass or more and 35% by mass or less.

(Hardening agent)
The metal oxide fine particle dispersion liquid containing the silicon-containing resin as the base component (B) may contain a curing agent for the silicon-containing resin. When the silicon-containing resin composition as the metal oxide fine particle dispersion liquid contains a curing agent, it is easy to form a metal oxide-containing film that is resistant to dissolution, swelling, and deformation by organic solvents such as N-methyl-2-pyrrolidone and has excellent organic solvent resistance.

Suitable examples of the curing agent for the silicon-containing resin include Bronsted acids such as hydrochloric acid, sulfuric acid, nitric acid, benzenesulfonic acid, and p-toluenesulfonic acid; imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole; organic amines such as 2,4,6-tris(dimethylaminomethyl)phenol, benzylmethylamine, DBU (1,8-diazabicyclo[5.4.0]-7-undecene), and DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea); phosphorus compounds represented by PX ¹ ₃ (wherein X ¹ is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms) such as phosphorus trichloride, phosphorus tribromide, phosphoric acid, trimethyl phosphate, triethyl phosphate, and tripropyl phosphate; and POX ¹ ₃ (wherein X diphosphorus pentoxide; phosphorus compounds represented by H( _HPO3 ) _xOH (wherein ^x is an integer of 1 or more), such as polyphosphoric acid and polyphosphate esters; phosphorus compounds represented by ^RDOPX12 (wherein RDO is a hydrogen atom or an organic group having 1 to 30 carbon atoms, and the hydrogen atom in the organic group may be substituted with a ^halogen atom; and ^X1 is a ^halogen atom, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms), _such as methyldichlorophosphine, ethyldichlorophosphine, and ^{methoxydichlorophosphine} ; dimethyl phosphite, diethyl phosphite, methylphosphonic acid, dimethyl methylphosphonate, methylphosphonic acid dichloride, phenylphosphonic ^acid , _{phenylphosphonic} acid dichloride, and benzylphosphonic acid diethyl. ^D0 is a hydrogen atom or an organic group having 1 to 30 carbon atoms, and the hydrogen atom in the organic group may be substituted with a halogen atom. and ¹ is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms; organic phosphorus compounds such as tributylphosphine, triphenylphosphine, tris(p-tolyl)phosphine, tris(m-tolyl)phosphine, tris(o-tolyl)phosphine, diphenylcyclohexylphosphine, tricyclohexylphosphine, tris(dimethoxyphenyl)phosphine, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride, and 1,4-bisdiphenylphosphinobutane; BX 1 3 (wherein X is a halogen atom, a hydroxyl group, or an alkoxy group having ^{1 to} ₆ carbon atoms) represented by the formula boron compounds represented by the formula R _D0 BX 1 ₂ (wherein ^{R D0} is a hydrogen atom or an organic group having 1 to 30 carbon atoms, and the hydrogen atom in the organic group may be substituted with a ^halogen atom; ^X represents a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms; boron oxide (B ^{2 O} ₃ ); phenylboronic acid, diisopropoxy(methyl)borane, methylboronic acid, cyclohexylboronic acid, etc. ¹ is a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 6 carbon atoms.); complexes of organic phosphorus compounds such as triphenylphosphine triphenylborane, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium thiocyanate, tetraphenylphosphonium dicyanamide, and n-butyltriphenylphosphonium dicyanamide; organic amine complexes of Lewis acids such as boron trifluoride (an example of the organic amine is piperidine); and amidines such as azabicycloundecene, diazabicycloundecene toluenesulfonate, and diazabicycloundecene octylate.

When the above polysilane is used as the base component (B), it is preferable to use a curing agent that generates a base component by light or heat, either in addition to the above curing agent or alone.

Curing Agent That Generates a Base Component by Heat As the curing agent that generates a base component by heat, any compound that has conventionally been used as a thermal base generator can be used without any particular limitation.
For example, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one can be used as a curing agent that generates a base component when heated. Note that 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one also generates a base when exposed to light.

（式（ｄ１）中、Ｒ^ｄ１、Ｒ^ｄ２、及びＲ^ｄ３は、それぞれ独立に水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、ホスフィノ基、スルホナト基、ホスフィニル基、ホスホナト基、又は有機基を示す。） In addition, a compound that generates an imidazole compound represented by the following formula (d1) upon heating (hereinafter, also referred to as a thermal imidazole generator) is also preferably used as a curing agent.

(In formula (d1), R ^d1 , R ^d2 , and R ^d3 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a phosphino group, a sulfonato group, a phosphinyl group, a phosphonato group, or an organic group.)

Examples of the organic group in R ^d1 , R ^d2 , and R ^d3 include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and an aralkyl group. The organic group may contain a bond or a substituent other than a hydrocarbon group, such as a heteroatom, in the organic group. The organic group may be linear, branched, or cyclic. The organic group is usually monovalent, but may be a divalent or higher organic group when forming a cyclic structure.

R ^d1 and R ^d2 may be bonded to form a cyclic structure, or may further contain a bond of a heteroatom. Examples of the cyclic structure include a heterocycloalkyl group and a heteroaryl group, and may be a condensed ring.

The bonds contained in the organic groups of R ^d1 , R ^d2 , and R ^d3 are not particularly limited as long as the effects of the present invention are not impaired, and the organic groups may contain bonds containing heteroatoms such as oxygen atoms, nitrogen atoms, silicon atoms, etc. Specific examples of bonds containing heteroatoms include ether bonds, thioether bonds, carbonyl bonds, thiocarbonyl bonds, ester bonds, amide bonds, urethane bonds, imino bonds (-N═C(-R ^d0 )-, -C(═NR ^d0 )-: R ^d0 represents a hydrogen atom or an organic group), carbonate bonds, sulfonyl bonds, sulfinyl bonds, azo bonds, etc.

As the bond containing a hetero atom which the organic group of R ^d1 , R ^d2 , and R ^d3 may have, from the viewpoint of the heat resistance of the imidazole compound, an ether bond, a thioether bond, a carbonyl bond, a thiocarbonyl bond, an ester bond, an amide bond, a urethane bond, an imino bond (-N═C(-R ^d0 )-, -C(═NR ^d0 )-: R ^d0 represents a hydrogen atom or an organic group), a carbonate bond, a sulfonyl bond, or a sulfinyl bond is preferable.

When the organic group of R ^d1 , R ^d2 , and R ^d3 is a substituent other than a hydrocarbon group, R ^d1 , R ^d2 , and R ^d3 are not particularly limited as long as the effect of the present invention is not impaired. Specific examples of R ^d1 , R ^d2 , and R ^d3 include a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, an isothiocyanato group, a silyl group, a silanol group, an alkoxy group, an alkoxycarbonyl group, a carbamoyl group, a thiocarbamoyl group, a nitro group, a nitroso group, a carboxylate group, an acyl group, an acyloxy group, a sulfino group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonato group, an alkyl ether group, an alkenyl ether group, an alkyl thioether group, an alkenyl thioether group, an aryl ether group, and an aryl thioether group. The hydrogen atoms contained in the above-mentioned substituents may be substituted with a hydrocarbon group. The hydrocarbon group contained in the above-mentioned substituents may be linear, branched, or cyclic.

R ^d1 , R ^d2 , and R ^d3 are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom, and more preferably a hydrogen atom.

The thermal imidazole generator is not particularly limited as long as it is a compound that can generate the imidazole compound represented by the above formula (d1) by heating. For compounds (thermal base generators) that generate amines by the action of heat, which have been conventionally incorporated into various compositions, a compound used as a thermal imidazole generator can be obtained by replacing the skeleton derived from the amine generated upon heating with a skeleton derived from the imidazole compound represented by the above formula (d1).

（式（ｄ２）中、Ｒ^ｄ１、Ｒ^ｄ２、及びＲ^ｄ３は、それぞれ独立に水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホナト基、又は有機基を示す。Ｒ^ｄ４及びＲ^ｄ５は、それぞれ独立に水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、又は有機基を示す。Ｒ^ｄ６、Ｒ^ｄ７、Ｒ^ｄ８、Ｒ^ｄ９、及びＲ^ｄ１０は、それぞれ独立に水素原子、ハロゲン原子、水酸基、メルカプト基、スルフィド基、シリル基、シラノール基、ニトロ基、ニトロソ基、スルフィノ基、スルホ基、スルホナト基、ホスフィノ基、ホスフィニル基、ホスホノ基、ホスホナト基、アミノ基、アンモニオ基、又は有機基を示す。Ｒ^ｄ６、Ｒ^ｄ７、Ｒ^ｄ８、Ｒ^ｄ９、及びＲ^ｄ１０は、それらの２つ以上が結合して環状構造を形成していてもよく、ヘテロ原子の結合を含んでいてもよい。）
で表される化合物が挙げられる。 Suitable thermal imidazole generators include those represented by the following formula (d2):

(In formula (d2), R ^d1 , R ^d2 , and R ^d3 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphonato group, or an organic group. R ^d4 and R ^d5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, or an organic group. R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R Each of ^d10 independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, or an organic group. Two or more of R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 may be bonded to form a cyclic structure, or may contain a bond of a heteroatom.
Examples of the compound include compounds represented by the following formula:

In formula (d2), R ^d1 , R ^d2 and R ^d3 are the same as those explained in formula (d1).

In formula (d2), R ^d4 and R ^d5 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, or an organic group.

Examples of the organic group in R ^d4 and R ^d5 include those exemplified for R ^d1 , R ^d2 , and R ^d3 . As in the case of R ^d1 , R ^d2 , and R ^d3 , the organic group may contain a heteroatom. In addition, the organic group may be linear, branched, or cyclic.

Among the above, R ^d4 and R ^d5 are each preferably independently a hydrogen atom, an alkyl group having from 1 to 10 carbon atoms, a cycloalkyl group having from 4 to 13 carbon atoms, a cycloalkenyl group having from 4 to 13 carbon atoms, an aryloxyalkyl group having from 7 to 16 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, an alkyl group having from 2 to 11 carbon atoms and a cyano group, an alkyl group having from 1 to 10 carbon atoms and a hydroxyl group, an alkoxy group having from 1 to 10 carbon atoms, an amide group having from 2 to 11 carbon atoms, an alkylthio group having from 1 to 10 carbon atoms, an acyl group having from 1 to 10 carbon atoms, an ester group having from 2 to 11 carbon atoms (-COOR ^d , -OCOR ^d : R ^d represents a hydrocarbon group), an aryl group having from 6 to 20 carbon atoms, an aryl group having from 6 to 20 carbon atoms and substituted with an electron donating group and/or an electron withdrawing group, a benzyl group substituted with an electron donating group and/or an electron withdrawing group, a cyano group, or a methylthio group. More preferably, both R ^d4 and R ^d5 are hydrogen atoms, or R ^d4 is a methyl group and R ^d5 is a hydrogen atom.

In formula (d2), R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, a sulfide group, a silyl group, a silanol group, a nitro group, a nitroso group, a sulfino group, a sulfo group, a sulfonato group, a phosphino group, a phosphinyl group, a phosphono group, a phosphonato group, an amino group, an ammonio group, or an organic group.

Examples of the organic group in R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 include those exemplified for R ^d1 , R ^d2 , and R ^d3 . As in the case of R ^d1 and R ^d2 , this organic group may contain a bond or a substituent other than a hydrocarbon group, such as a heteroatom, in the organic group. In addition, this organic group may be linear, branched, or cyclic.

R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 may be bonded together to form a cyclic structure, or may contain a bond of a heteroatom. Examples of the cyclic structure include a heterocycloalkyl group, a heteroaryl group, and the like, and may be a condensed ring. For example, R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 may be bonded together to form a condensed ring such as naphthalene, anthracene, phenanthrene, or indene by sharing the atom of the benzene ring to which R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 are bonded.

Among the above, R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 are each independently preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 4 to 13 carbon atoms, a cycloalkenyl group having 4 to 13 carbon atoms, an aryloxyalkyl group having 7 to 16 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an alkyl group having 2 to 11 carbon atoms and a cyano group, an alkyl group having 1 to 10 carbon atoms and a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an amide group having 2 to 11 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an acyl group having 1 to 10 carbon atoms, an ester group having 2 to 11 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms and substituted with an electron donating group and/or an electron withdrawing group, a benzyl group substituted with an electron donating group and/or an electron withdrawing group, a cyano group, a methylthio group, or a nitro group.

It is also preferable that two or more of R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 are bonded to each other to form a fused ring such as naphthalene, anthracene, phenanthrene, indene, etc. by sharing the atoms of the benzene ring to which R ^d6 , R ^d7 , R ^d8 , R ^d9 , and R ^d10 are bonded.

（式（ｄ３）中、Ｒ^ｄ１、Ｒ^ｄ２、及びＲ^ｄ３は、式（ｄ１）及び（ｄ２）と同義である。Ｒ^ｄ４～Ｒ^ｄ９は式（ｄ２）と同義である。Ｒ^ｄ１１は、水素原子又は有機基を示す。Ｒ^ｄ６及びＲ^ｄ７が水酸基となることはない。Ｒ^ｄ６、Ｒ^ｄ７、Ｒ^ｄ８、及びＲ^ｄ９は、それらの２つ以上が結合して環状構造を形成していてもよく、ヘテロ原子の結合を含んでいてもよい。）
で表される化合物が好ましい。 Among the compounds represented by the above formula (d2), those represented by the following formula (d3):

(In formula (d3), R ^d1 , R ^d2 , and R ^d3 are the same as those in formulae (d1) and (d2). R ^d4 to R ^d9 are the same as those in formula (d2). R ^d11 represents a hydrogen atom or an organic group. R ^d6 and R ^d7 are not hydroxyl groups. Two or more of R ^d6 , R ^d7 , R ^d8 , and R ^d9 may be bonded to form a cyclic structure or may contain a bond to a heteroatom.)
Preferred is a compound represented by the following formula:

The compound represented by formula (d3) has excellent solubility in organic solvents because it has the substituent --O--R ^d11 .

In formula (d3), R ^d11 is a hydrogen atom or an organic group. When R ^d11 is an organic group, examples of the organic group include those exemplified in R ^d1 , R ^d2 , and R ^d3 . The organic group may contain a heteroatom in the organic group. The organic group may be linear, branched, or cyclic. R ^d11 is preferably a hydrogen atom, an alkyl group or an alkoxyalkyl group having 1 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a methoxymethyl group, an ethoxymethyl group, a methoxyethyl group, an ethoxyethyl group, a propoxymethyl group, or a butoxymethyl group.

Specific examples of compounds that are particularly suitable as thermal imidazole generators are shown below.

The compounds represented by formula (d2) or (d3) can be decomposed by the action of light in addition to heating to generate imidazole compounds.

Oxime ester compound The oxime ester compound is decomposed by the action of light to generate a base. Preferred examples of the oxime ester compound are the same as the preferred examples of the oxime ester compound described for the energy-sensitive composition of the first embodiment.

The silicon-containing resin composition may contain two or more different classes or types of curing agents.
The content of the curing agent in the silicon-containing resin composition is typically preferably 0.01 mass % or more and 40 mass % or less, more preferably 0.1 mass % or more and 20 mass % or less, and particularly preferably 1 mass % or more and 10 mass % or less, based on the mass of the solid content of the silicon-containing resin composition.

(Ionic Liquid)
The silicon-containing resin composition may contain an ionic liquid. When the silicon-containing resin composition contains an ionic liquid, the dispersion stability of the metal oxide (A) in the silicon-containing resin composition can be further improved.
As the ionic liquid, the ionic liquid described in the energy-sensitive composition of the sixth embodiment can be suitably used. The ionic liquid may be used alone or in combination of two or more kinds.
The content of the ionic liquid is not particularly limited as long as the effects of the present invention can be achieved.
The content of the ionic liquid in the silicon-containing resin composition is preferably 10 parts by mass or more and 500 parts by mass or less, more preferably 90 parts by mass or more and 400 parts by mass or less, and even more preferably 100 parts by mass or more and 300 parts by mass or less, per 100 parts by mass of the metal oxide (A).

(solvent)
The silicon-containing resin composition usually contains a solvent. The solvent preferably contains a solvent (S1) which is a compound having a cyclic skeleton and containing heteroatoms other than hydrogen and carbon atoms. That is, the solvent (S1) is a non-hydrocarbon solvent. Examples of heteroatoms that may be contained in the solvent (S1) include N, O, S, and P.

When the solvent contains the solvent (S1), the dispersion stability of the metal oxide (A) can be further improved.
For example, it is presumed that the cyclic skeleton of the solvent (S1) exerts an effect of inhibiting aggregation of the metal oxide (A).

The cyclic skeleton of the solvent (S1) is preferably an alicyclic skeleton. Here, a cyclic skeleton that does not exhibit aromaticity is defined as an alicyclic skeleton. In addition, when the solvent (S1) has both an aromatic ring skeleton and an alicyclic skeleton, such as a tetralin ring, the solvent (S1) is defined as having an alicyclic skeleton.
Although the reason is unclear, it is presumed that the fact that the alicyclic skeleton is somewhat bulkier than an aromatic ring skeleton having a planar three-dimensional structure contributes favorably to the dispersion stabilization of the metal oxide (A).

The solvent (S1) preferably has one or more bonds selected from the group consisting of an ester bond (-CO-O-), an amide bond (-CO-NH-), a carbonate bond (-O-CO-O-), a ureido bond (-NH-CO-NH-), and a urethane bond (-O-CO-NH-).
In the present specification, when simply described as an ester bond and an amide bond, they mean a "carboxylic acid ester bond" and a "carboxylic acid amide bond", respectively.
In the amide bond, ureido bond, and urethane bond, an organic group may be bonded to the nitrogen atom. The type of the organic group is not particularly limited. As the organic group, an alkyl group is preferable, an alkyl group having 1 to 6 carbon atoms is more preferable, and a methyl group and an ethyl group are further preferable.
When the solvent (S1) contains these bonds, the silicon-containing resin tends to be easily dissolved in the silicon-containing resin composition.

Preferred examples of the solvent (S1) include aromatic solvents such as anisole, phenetole, propyl phenyl ether, butyl phenyl ether, cresyl methyl ether, ethyl benzyl ether, diphenyl ether, dibenzyl ether, acetophenone, propiophenone, benzophenone, pyridine, pyrimidine, pyrazine, and pyridazine; alicyclic alcohols such as cyclopentanol, cyclohexanol, 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanedimethanol, and 1,3-cyclohexanedimethanol; alicyclic alcohols such as cyclohexyl methyl ether, cyclohexyl ethyl ether, tetrahydrofuran, tetrahydropyran, and dioxane; Cyclic ethers; alicyclic ketones such as cyclopentanone, cyclohexanone, cycloheptanone, 2-methylcyclohexanone, 1,4-cyclopentanedione, and 1,3-cyclopentanedione; lactones such as β-propiolactone, γ-butyrolactone, β-methyl-γ-butyrolactone, δ-valerolactone, ε-valerolactone, ε-caprolactone, α-methyl-ε-caprolactone, and ε-methyl-ε-caprolactone; cyclic amides or cyclic ureas such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N,N-dimethylpropylene urea; and cyclic carbonates such as ethylene carbonate and propylene carbonate.

（式（ｓ１）中、Ｒ^ｓ１は、炭素原子数１以上３以下のアルキル基であり、Ｒ^ｓ２は、炭素原子数１以上６以下のアルキル基であり、ｐは１以上６以下の整数であり、ｑは０以上（ｐ＋１）以下の整数である。）
で表される、カルボン酸のシクロアルキルエステルが好ましい。 The solvent (S1) is preferably a cycloalkyl ester of a carboxylic acid. The cycloalkyl ester of a carboxylic acid is represented by the following formula (s1):

(In formula (s1), R ^s1 is an alkyl group having 1 to 3 carbon atoms, R ^s2 is an alkyl group having 1 to 6 carbon atoms, p is an integer of 1 to 6, and q is an integer of 0 to (p+1).)
Preferred are cycloalkyl esters of carboxylic acids represented by the formula:

Examples of R ^s1 in the formula (s1) include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group, and a methyl group is preferable.
Examples of R ^s2 in formula (s1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. The alkyl group represented by R ^s2 is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or an n-butyl group, and more preferably a methyl group or an ethyl group.

Suitable examples of cycloalkyl carboxylates represented by formula (s1) include cyclopropyl acetate, cyclobutyl acetate, cyclopentyl acetate, cyclohexyl acetate, cycloheptyl acetate, cyclooctyl acetate, cyclopropyl propionate, cyclobutyl propionate, cyclopentyl propionate, cyclohexyl propionate, cycloheptyl propionate, and cyclooctyl propionate. Among these, cyclopentyl acetate and cyclohexyl acetate are preferred because they are easily available and have a preferred boiling point.

Among the solvents (S1) described above, cycloalkyl carboxylates represented by formula (s1) are preferred, with cyclopentyl acetate and cyclohexyl acetate being particularly preferred.

Suitable examples of the solvent other than the solvent (S1) include alcohols such as methanol, ethanol, propanol, and n-butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; ketones such as acetone, methyl ethyl ketone, methyl-n-amyl ketone, methyl isoamyl ketone, and 2-heptanone; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; monomethyl ethers, monoethyl ethers, and monopropyl ethers of the polyhydric alcohols or the compounds having an ester bond. ether derivatives such as monobutyl ether, monophenyl ether, etc.; esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc.; aromatic organic solvents such as ethylbenzene, diethylbenzene, amylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc.; nitrogen-containing organic solvents such as N,N,N',N'-tetramethylurea, N,N,2-trimethylpropionamide, N,N-dimethylacetamide, N,N-dimethylformamide, N,N-diethylacetamide, N,N-diethylformamide, N-ethylpyrrolidone, etc. Two or more of these solvents may be used in combination.

Other solvents than solvent (S1) are preferably propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), N,N,N',N'-tetramethylurea, and butanol.

When the solvent contains solvent (S1), the content of solvent (S1) in the solvent is preferably 30% by mass or more, more preferably 45% by mass or more and 99.99% by mass or less, and even more preferably 50% by mass or more and 99% by mass or less.

When the silicon-containing resin composition contains polysilane as the base component (B), the water content of the silicon-containing resin composition is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, and particularly preferably less than 0.3% by mass, in order to suppress cracks in the metal oxide-containing film. The water content of the silicon-containing resin composition can be measured by the Karl Fischer measurement method.
The moisture in the silicon-containing resin composition is often derived from the solvent, and therefore it is preferable to dehydrate the solvent so that the moisture content of the silicon-containing resin composition is within the above range.

The amount of the solvent used is not particularly limited as long as it does not impede the object of the present invention. From the viewpoint of film-forming properties, the solvent is used so that the solids concentration of the silicon-containing resin composition is preferably 1% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less.

(Other ingredients)
The silicon-containing resin composition may contain various additives that have been conventionally added to silicon-containing resin compositions for forming silica-based films, provided that the additives do not impair the object of the present invention.
Examples of such additives include base generators, catalysts, sensitizers, silane coupling agents, adhesion enhancers, dispersants, surfactants, UV absorbers, antioxidants, defoamers, viscosity modifiers, resins, rubber particles, and colorants.
When the silicon-containing resin composition contains an alkali-soluble resin as the resin, the silicon-containing resin composition is endowed with alkali developability.
Furthermore, when the silicon-containing resin composition contains rubber particles, elasticity is imparted to the metal oxide-containing film that is formed, which makes it easier to eliminate the brittleness of the metal oxide-containing film.

In addition, the silicon-containing resin composition preferably contains a nitroxy compound, which is a compound that can exist stably as a nitroxide radical.
It is preferable that the silicon-containing resin composition contains a nitroxy compound, because the residue (silica-derived impurities generated by baking) of the metal oxide-containing film can be reduced even if the baking temperature when forming the silica-based metal oxide-containing film is a low temperature of, for example, 250° C. or less (for example, in the range of 200° C. to 250° C.). If the residue in the metal oxide-containing film is small, gas generation from the metal oxide-containing film derived from the residue itself or decomposition products of the residue is suppressed even when the metal oxide-containing film is placed in a high-temperature atmosphere or a reduced-pressure atmosphere.

Specific examples of suitable nitroxy compounds include di-tert-butyl nitroxide, di-1,1-dimethylpropyl nitroxide, di-1,2-dimethylpropyl nitroxide, di-2,2-dimethylpropyl nitroxide, and compounds of the following formula:
In the following formula, R ^N1 each independently represents an alkyl group having from 1 to 20 carbon atoms which may have a substituent, an aromatic group which may have a substituent, or an alicyclic group which may have a substituent.

More preferred nitroxy compounds are 2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-carboxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-methacrylic acid-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-acrylic acid-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-oxo-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, and 3-carboxy-2,2,5,5-tetramethylpyrrolidine 1-oxyl, because they are particularly likely to reduce residues even when baked at a low temperature. free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-(2-chloroacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxylbenzoate free radical, 4-isothiocyanato-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, 4-(2-iodoacetamido)-2,2,6,6-tetramethylpiperidine 1-oxyl free radical, and 4-methoxy-2,2,6,6-tetramethylpiperidine 1-oxyl free radical.
The nitroxy compounds may be used alone or in combination of two or more kinds.

The content of the nitroxy compound in the silicon-containing resin composition may be a small amount.The content of the nitroxy compound in the silicon-containing resin composition is preferably 0.005% by mass or more, more preferably 0.009% by mass or more, based on the total mass of the components other than the solvent of the silicon-containing resin composition, because the residue is easily reduced even when baked at a low temperature.
The content of the nitroxy compound in the silicon-containing resin composition is preferably 2 mass % or less, and more preferably 1 mass % or less, based on the total mass of the components other than the solvent in the silicon-containing resin composition.

The silicon-containing resin composition preferably contains an antioxidant. When the silicon-containing resin composition contains an antioxidant, it is easy to suppress the deterioration of various effects obtained depending on the type of metal oxide (A) of the metal oxide-containing film.
The antioxidant preferably includes at least one selected from the group consisting of phosphorus-based, sulfur-based and phenol-based antioxidants.

The type of phosphorus-based antioxidant is not particularly limited, and specific examples include 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, diisodecylpentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus, 6-[3- (3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1,3,2]dioxaphosphepine, triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenylditridecyl)phosphite, octadecyl phosphite, tris(nonylphenyl)phosphite, 9,10-dihydro-9-oxaphosphite -10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris(2,4-di-tert-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-tert-butylphenyl)phosphite, cyclic Examples of suitable phosphates include neopentane tetraylbis(2,6-di-tert-butylphenyl)phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, tris(2,4-di-tert-butylphenyl)phosphite, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester, and phosphonic acid.

Among phosphorus-based antioxidants, in terms of heat resistance and heat discoloration prevention of metal oxide-containing films, 2,2'-methylenebis(4,6-di-tert-butyl-1-phenyloxy)(2-ethylhexyloxy)phosphorus, 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, and 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1,3,2]dioxaphosphepine, etc. are preferred.

Commercially available phosphorus-based antioxidants include Irgafos 168 (manufactured by BASF) and Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.).

The type of sulfur-based antioxidant is not particularly limited, and specific examples include 2,2-bis({[3-(dodecylthio)propionyl]oxy}methyl)-1,3-propanediyl-bis[3-(dodecylthio)propionate], 2-mercaptobenzimidazole, dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, pentaerythrityl-tetrakis(3-laurylthiopropionate), 2-mercaptobenzimidazole, etc.

Among sulfur-based antioxidants, 2,2-bis({3-(dodecylthio)propionyl}oxy)methyl)1,3-propanediyl-bis[3-(dodecylthio)propionate], 2-mercaptobenzimidazole, etc. are preferred in terms of heat resistance and heat discoloration prevention of metal oxide-containing films.

Commercially available sulfur-based antioxidants include Irganox 1035 (manufactured by BASF).

The type of phenolic antioxidant is not particularly limited, and specific examples include 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethoxy]-2,4,8,10-tetraoxaspiro[5.5]undecane, pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)benzene, and triethylene Glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-tert-butyl-3-methylphenol), tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-isocyanurate, 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylene N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2,4-bis[(octylthio)methyl]-O-cresol, 1,6-hexanediol-bis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-[3-(3 ,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidene-bis(3-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-tris(4-hydroxybenzyl)benzene, and tetrakis[methylene-3-(3,5'-di-tert-butyl-4'-hydroxyphenylpropionate)]methane, etc. can be mentioned.

Among phenol-based antioxidants, in terms of heat resistance and heat discoloration prevention of metal oxide-containing films, 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethoxy]-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3,5-trimethyl-2,4,6-tris(3',5'-di-tert-butyl-4-hydroxybenzyl)benzene, pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-tert-butyl-3-methylphenol), tris -(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-isocyanurate, 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and 2,4-bis[(octylthio)methyl]-O-cresol are preferred.

Commercially available phenolic antioxidants include Irganox 1010 (manufactured by BASF) and ADK STAB AO-80 (manufactured by ADEKA).

The content of the antioxidant is, for example, 0.01% by mass or more and 30% by mass or less, preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 8% by mass or less, and even more preferably 1% by mass or more and 5% by mass or less, based on the total mass of the solid content of the silicon-containing resin composition. By keeping the content within the above range, it is possible to suppress a decrease in various effects obtained according to the type of metal oxide (A) of the metal oxide-containing film. In addition, when patterning is performed by a printing method or the like using the silicon-containing resin composition, peeling of the formed pattern is easily suppressed.

The photosensitive or heat-sensitive metal oxide fine particle dispersion liquid, as typified by the energy-sensitive compositions of the first to sixth aspects above, and the silicon-containing resin composition may contain various additives as necessary. Examples of additives include sensitizers, curing accelerators, fillers, adhesion promoters, antioxidants, UV absorbers, aggregation inhibitors, thermal polymerization inhibitors, defoamers, leveling agents, surfactants, thickeners, etc.

Examples of sensitizers include the compounds exemplified for the energy-sensitive composition of the fifth embodiment. Sensitizers can be used alone or in combination of two or more.

When each composition contains a photoacid generator, the content of the sensitizer is preferably 0.1 to 6 in molar ratio relative to the photoacid generator, and more preferably 0.2 to 4 in molar ratio. By keeping the content within the above range, the sensitivity and curability of each composition will be good.

Examples of the filler include known fillers such as barium sulfate, barium titanate, silica, talc, clay, magnesium carbonate, calcium carbonate, and mica.
The content of the filler is preferably 60% by mass or less, and more preferably 5% by mass or more and 40% by mass or less, based on the solid content of each composition.

Examples of surfactants include commercially available fluorine-based surfactants such as BM-1000, BM-1100 (all manufactured by BM Chemie), Megafac F142D, Megafac F172, Megafac F173, Megafac F183 (all manufactured by Dainippon Ink & Chemicals), Fluorad FC-135, Fluorad FC-170C, Fluorad FC-430, Fluorad FC-431 (all manufactured by Sumitomo 3M), Surflon S-112, Surflon S-113, Surflon S-131, Surflon S-141, Surflon S-145 (all manufactured by Asahi Glass Co., Ltd.), SH-28PA, SH-190, SH-193, SZ-6032, SF-8428 (all manufactured by Toray Silicone Co., Ltd.), but are not limited to these.

Thickening agents include ultrafine silica, montmorillonite, etc.

Examples of defoaming agents and/or leveling agents include silicone-based polymers, fluorine-based polymers, etc.

The adhesion imparting agent may be a silane coupling agent.
In addition, the photosensitive compositions or silicon-containing resin compositions of the first to sixth aspects may contain, as an optional additive, benzotriazole derivatives such as 1-(N,N-di(2-ethylhexyl)amino)methyl-1H-benzotriazole, 1-(N,N-di(2-ethylhexyl)amino)methyl-1H-methylbenzotriazole, carboxybenzotriazole, benzotriazole, methylbenzotriazole, dihydroxypropylbenzotriazole, and bisaminomethylbenzotriazole, either alone or in combination of two or more.

The amount of each of the above-mentioned various additives that may be contained in the metal oxide microparticle dispersion may be appropriately adjusted within the range of, for example, 0.001% to 10% by mass, and is preferably 0.1% to 5% by mass, based on the total composition, unless otherwise specified.

<Method for preparing metal oxide fine particle dispersion>
The metal oxide fine particle dispersion is prepared by mixing the above-mentioned components with a stirrer. The surface-modified metal oxide fine particles as the metal oxide (A) may be blended into the metal oxide fine particle dispersion in a state where they are dispersed in a dispersion medium, or may be blended into the metal oxide fine particle dispersion in a state where they contain no or almost no dispersion medium.
The prepared metal oxide fine particle dispersion may be filtered using a membrane filter or the like so as to make it uniform.

<Method for producing metal oxide-containing film>
By using the above-described metal oxide fine particle dispersion liquid containing the metal oxide (A), a metal oxide-containing film can be formed.

When the metal oxide fine particle dispersion contains a resin material such as polyacetal resin, polyamide resin, polycarbonate resin, polyester resin (polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyarylate, etc.), FR-AS resin, FR-ABS resin, AS resin, ABS resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, fluorine-based resin, polyimide resin, polyamideimide resin, polyamide bismaleimide resin, polyetherimide resin, polybenzoxazole resin, polybenzothiazole resin, polybenzimidazole resin, silicone resin, BT resin, polymethylpentene, ultra-high molecular weight polyethylene, FR-polypropylene, (meth)acrylic resin (e.g., polymethyl methacrylate, etc.), and polystyrene as the base component (B), the method for forming the metal oxide-containing film is as described above.

When the metal oxide microparticle dispersion contains a thermosetting material as the base component (B), the metal oxide microparticle dispersion can be formed into a film by a method such as coating, and the formed film can then be heated to a temperature according to the type of curable material to cure it, thereby forming a metal oxide-containing film.

When the metal oxide fine particle dispersion is the above-mentioned various photosensitive compositions, typically,
applying a metal oxide fine particle dispersion onto a substrate to form a coating film;
and exposing the coated film to light, thereby producing a metal oxide-containing film.

More specifically, a coating film is formed by a suitable coating method. For example, a metal oxide fine particle dispersion liquid is applied onto a substrate using a contact transfer type coating device such as a roll coater, a reverse coater, or a bar coater, or a non-contact type coating device such as a spinner (rotary coating device), a curtain flow coater, or an inkjet, and then dried to form a coating film.
The drying method is not particularly limited, and examples thereof include (1) a method of pre-baking on a hot plate at a temperature of 80° C. to 120° C., preferably 90° C. to 100° C., for 60 seconds to 120 seconds, (2) a method of leaving it at room temperature for several hours to several days, and (3) a method of placing it in a hot air heater or an infrared heater for several tens of minutes to several hours to remove the solvent.

Next, the coating film is exposed to electromagnetic waves in a position-selective manner. When the dispersion of metal oxide fine particles is a negative-type photosensitive composition that is cured by exposure, the entire surface of the coating film may be exposed to light.
When the exposure is performed selectively, the electromagnetic waves may be irradiated through a positive or negative mask, or may be irradiated directly. The exposure dose varies depending on the composition of the metal oxide fine particle dispersion, but is preferably, for example, about 5 mJ/ ^cm2 or more and 500 mJ/ ^cm2 or less.

When the exposure is carried out over the entire surface of the coating film, the exposed coating film can be used as it is as a metal oxide-containing film.
When the exposure is carried out site-selectively, the exposed coating film is developed with a developer to obtain a metal oxide-containing film patterned into a desired shape.
The developing method is not particularly limited, and may be, for example, a dipping method, a spray method, etc. Examples of the developing solution include organic developing solutions such as monoethanolamine, diethanolamine, and triethanolamine, and aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, and quaternary ammonium salts.

After development, the patterned metal oxide-containing film is preferably post-baked at a temperature of about 200°C or higher and 250°C or lower.

When the metal oxide fine particle dispersion is a silicon-containing resin composition containing a silicon-containing resin as the base component (B), a coating film of the silicon-containing resin composition as the metal oxide fine particle dispersion is baked to produce a metal oxide-containing film.
In this case, the material of the substrate is not particularly limited as long as it can withstand baking. Suitable examples of the substrate material include inorganic materials such as metal, silicon, and glass, and heat-resistant materials such as polycarbonate, polyethylene terephthalate, polyethersulfone, polyimide resin, and polyamideimide resin. The thickness of the substrate is not particularly limited, and the substrate may be a film or a sheet.

The substrate with the coating film is then baked. The baking method is not particularly limited, but the baking is typically performed using an electric furnace or the like. The baking temperature is typically preferably 300°C or higher, more preferably 350°C or higher. The upper limit is not particularly limited, but is, for example, 1000°C or lower. When the silicon-containing resin composition contains the above-mentioned curing agent and/or nitroxy compound, the residue (impurities derived from the silica film) in the metal oxide-containing film, which is a silica film, can be reduced even if the lower limit of the baking temperature is lowered to 200°C. The baking atmosphere is not particularly limited, and may be in an inert gas atmosphere such as a nitrogen atmosphere or an argon atmosphere, under vacuum, or under reduced pressure. It may be in the air, or the oxygen concentration may be appropriately controlled.

The metal oxide-containing film formed by the above method is suitable for use as a high refractive index film in optical elements, a passivation film in electronic elements, etc., depending on the performance of the metal oxide-containing film according to the composition of the metal oxide microparticle dispersion liquid.

The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

Example 1
782 parts by mass of a mineral spirit solution of zirconium salt of 2-ethylhexanoic acid (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd., concentration of zirconium salt of 2-ethylhexanoic acid: 44% by mass) and 268 parts by mass of pure water were mixed.
The mixture thus obtained was placed in an autoclave, and after the interior of the autoclave was filled with nitrogen gas, the mixture was heated to 180° C. with stirring, and was then kept stirred at the same temperature for 16 hours.
After the stirring was completed, the solid matter in the autoclave was collected by filtration. The collected solid matter was washed with acetone and then dried. 100 parts by mass of the dried solid matter was dispersed in 800 mL of toluene to form a cloudy solution. The cloudy solution was filtered with filter paper (No. 5C) to remove coarse particles. Toluene was thoroughly removed from the filtrate using a rotary evaporator to obtain dried white zirconium oxide microparticles.

100 parts by mass of the obtained zirconium oxide microparticles and 10 parts by mass of a carboxylic acid compound (CA1) of the following formula as a coating agent were added to 100 parts by mass of methyl ethyl ketone, and the zirconium oxide microparticles in the methyl ethyl ketone were then stirred for 10 minutes to coat the surfaces of the zirconium oxide microparticles with the carboxylic acid compound of the following formula.
The liquid after stirring was thoroughly distilled with a rotary evaporator to recover zirconium oxide. The recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent is attached to the surface of the zirconium oxide. In addition, when the observation results of the raw material (CA1), the observation results of the zirconium oxide fine particles before the CA1 coating treatment, and the observation results of the zirconium oxide fine particles after the CA1 coating treatment are compared by XPS for nitrogen (N1s electrons), it is also found that a coating agent is attached to the surface of the zirconium oxide because a peak derived from nitrogen (N1s electrons) different from that of the raw material CA1 is observed in the zirconium oxide fine particles after the coating treatment.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability using the following method.

<Evaluation of dispersion stability in organic solvent>
50 parts by mass of the surface-modified zirconium oxide in the form of a starch syrup was uniformly dispersed in 100 parts by mass of methyl ethyl ketone (MEK) to obtain a metal oxide fine particle dispersion for evaluating dispersion stability.
The obtained metal oxide fine particle dispersion was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed. After further standing at room temperature for 60 days (total of 90 days), aggregation of the zirconium oxide fine particles was visually observed.

<Evaluation of Dispersion Stability in (Meth)acrylic Resin-Containing Composition>
70 parts by mass of a (meth)acrylic resin which is a terpolymer of the following formula, 30 parts by mass of a (meth)acrylic resin which is a binary copolymer of the following formula, 5 parts by mass of a curing agent (naphthalic acid derivative) represented by the following formula, and 45 parts by mass of starch syrup-like surface-modified zirconium oxide were dissolved and dispersed in 700 parts by mass of propylene glycol monomethyl ether acetate to obtain a metal oxide fine particle dispersion for evaluating dispersion stability. The amount of zirconium oxide used was 30% by mass of the solid content.
In the following formula, the numbers to the bottom right of each structural unit indicate the content (mass %) of each structural unit in the resin.

The resulting metal oxide microparticle dispersion was left to stand for 30 days, after which the zirconium oxide microparticles remained stably dispersed.

<Evaluation of Dispersion Stability in a Composition Containing a Curable Aromatic Compound>
As the curable compound, a compound represented by the following formula was used.

As the curing agent, a compound represented by the following formula, which is a photocationic polymerization initiator, was used.

69.95 parts by mass of the above-mentioned curable compound, 30 parts by mass of the starch syrup-like surface-modified zirconium oxide, and 0.35 parts by mass of the above-mentioned curing agent were dissolved and dispersed in propylene glycol monomethyl ether acetate to a solids concentration of 20% by mass, thereby obtaining a metal oxide microparticle-containing dispersion liquid for evaluating dispersion stability.
The resulting dispersion of metal oxide fine particles was allowed to stand for 30 days, after which the zirconium oxide fine particles remained stably dispersed.

Example 2
Except for changing methyl ethyl ketone to propylene glycol monomethyl ether, coating treatment of zirconium oxide fine particles was carried out using a carboxylic acid compound (CA1) in the same manner as in Example 1. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand at room temperature for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for an additional 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 3
50 parts by mass of dried white zirconium oxide fine particles were mixed with 50 parts by mass of a 5% by mass aqueous sodium hydroxide solution, and then the resulting mixture and 10 parts by mass of the carboxylic acid compound (CA1) were added to 50 parts by mass of propylene glycol monomethyl ether. The zirconium oxide fine particles in the propylene glycol monomethyl ether were then stirred for 10 minutes to coat the surfaces of the zirconium oxide fine particles with the carboxylic acid compound (CA1).
The propylene glycol monomethyl ether and water were thoroughly removed from the liquid after stirring using a rotary evaporator to recover zirconium oxide. The recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicated that a coating agent had adhered to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand at room temperature for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for an additional 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 4
50 parts by mass of dried white zirconium oxide fine particles were mixed with 50 parts by mass of propylene glycol monomethyl ether, and then a mixed solution in which 3 parts by mass of a carboxylic acid compound (CA1) was dissolved in advance in 30 parts by mass of N,N,N',N'-tetramethylurea (TMU) was added. The zirconium oxide fine particles were stirred for 10 minutes to coat the surfaces of the zirconium oxide fine particles with the carboxylic acid compound (CA1).
The propylene glycol monomethyl ether and N,N,N',N'-tetramethylurea were thoroughly removed from the liquid after stirring using a rotary evaporator to recover zirconium oxide. The recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicated that a coating agent had adhered to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of the dispersion stability in an organic solvent, the zirconium oxide fine particles remained stably dispersed even when the metal oxide fine particle dispersion was allowed to stand at room temperature for 90 days.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.
A comparison of Examples 1 to 3 with Example 4 shows that the dispersion stability of zirconium oxide microparticles in an organic solvent was improved by coating with a carboxylic acid compound (CA1) in the presence of N,N,N',N'-tetramethylurea, a compound having an amide structure.

Example 5
A coating treatment of zirconium oxide fine particles was carried out using the carboxylic acid compound (CA1) in the same manner as in Example 2, except that the carboxylic acid compound (CA1) was used as an N,N,N',N'-tetramethylurea solution with a concentration of 5 mass %. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of the dispersion stability in an organic solvent, the zirconium oxide fine particles remained stably dispersed even after the metal oxide fine particle dispersion was allowed to stand at room temperature for 90 days.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.
A comparison of Examples 1 to 3 with Example 5 shows that the dispersion stability of zirconium oxide microparticles in an organic solvent was improved by coating with a carboxylic acid compound (CA1) in the presence of N,N,N',N'-tetramethylurea, a compound having an amide structure.

Comparative Example 1
Coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 1, except that the carboxylic acid compound (CA1) was changed to 3-methacryloxypropyltrimethoxysilane.
The recovered zirconium oxide after coating treatment was a sticky solid with a wet feeling. The change in properties indicates that the coating agent had adhered to the surface of the zirconium oxide.

The obtained surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1. Note that the evaluation of the dispersion stability in an organic solvent was omitted.
As a result, in an evaluation of dispersion stability in a composition containing a curable aromatic compound, aggregation of zirconium oxide microparticles was observed when the metal oxide microparticle dispersion was allowed to stand at room temperature for 2 hours, and in an evaluation of dispersion stability in a (meth)acrylic resin-containing composition, aggregation of zirconium oxide microparticles was observed when the metal oxide microparticle dispersion was allowed to stand at room temperature for 1 day.

Comparative Example 2
Coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 1, except that the carboxylic acid compound (CA1) was changed to mono 2-acryloyloxyethyl phthalate.
The recovered zirconium oxide after coating treatment was a sticky solid with a wet feeling. The change in properties indicates that the coating agent had adhered to the surface of the zirconium oxide.

The dispersion stability of the obtained surface-modified zirconium oxide was evaluated in the same manner as in Example 1. Note that the evaluation of the dispersion stability in an organic solvent was omitted.
As a result, in an evaluation of dispersion stability in a composition containing a curable aromatic compound, aggregation of zirconium oxide microparticles was observed when the metal oxide microparticle dispersion was allowed to stand at room temperature for 6 hours, and in an evaluation of dispersion stability in a (meth)acrylic resin-containing composition, aggregation of zirconium oxide microparticles was observed when the metal oxide microparticle dispersion was allowed to stand at room temperature for 1 day.

Comparative Example 3
Except for changing the carboxylic acid compound (CA1) to succinic acid mono 2-acryloyloxyethyl ester, coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 1. As a result, the mixed liquid during the coating treatment gelled, and the zirconium oxide after the coating treatment could not be recovered.

Example 6
A coating process of zirconium oxide fine particles was carried out in the same manner as in Example 2, except that the zirconium oxide to be coated with the carboxylic acid compound (CA1) was changed to the wet, sticky solid zirconium oxide obtained in Comparative Example 1. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand at room temperature for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for an additional 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 7
A coating process of zirconium oxide fine particles was carried out in the same manner as in Example 4, except that the zirconium oxide to be coated with the carboxylic acid compound (CA1) was changed to the wet, sticky solid zirconium oxide obtained in Comparative Example 1. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of the dispersion stability in an organic solvent, the zirconium oxide fine particles remained stably dispersed even when the metal oxide fine particle dispersion was allowed to stand at room temperature for 90 days.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.
A comparison of Examples 1 to 3 and Example 6 with Example 7 shows that the dispersion stability of zirconium oxide microparticles in an organic solvent was improved by coating with a carboxylic acid compound (CA1) in the presence of N,N,N',N'-tetramethylurea, a compound having an amide structure.

Example 8
Except for changing the carboxylic acid compound (CA1) to L-arginine (CA2) as the carboxylic acid compound, coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 1. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. From the change in properties, it can be seen that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand at room temperature for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for an additional 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 9
A coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 2, except that the carboxylic acid compound (CA1) was changed to L-arginine (CA2) as the carboxylic acid compound. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand at room temperature for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for an additional 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 10
A coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 3, except that the carboxylic acid compound (CA1) was changed to L-arginine (CA2) as the carboxylic acid compound. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of dispersion stability in an organic solvent, when a metal oxide microparticle dispersion was left to stand for 30 days, the zirconium oxide microparticles remained stably dispersed. However, when the dispersion was further left to stand at room temperature for another 60 days (a total of 90 days), aggregation of the zirconium oxide microparticles was visually observed.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.

Example 11
A coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 4, except that the carboxylic acid compound (CA1) was changed to L-arginine (CA2) as the carboxylic acid compound. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of the dispersion stability in an organic solvent, the zirconium oxide fine particles remained stably dispersed even after the metal oxide fine particle dispersion was allowed to stand at room temperature for 90 days.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.
A comparison of Examples 1 to 3 and Example 10 with Example 11 shows that the dispersion stability of zirconium oxide microparticles in an organic solvent was improved by coating with a carboxylic acid compound (CA2) in the presence of N,N,N',N'-tetramethylurea, a compound having an amide structure.

Example 12
A coating treatment of zirconium oxide fine particles was carried out in the same manner as in Example 5, except that the carboxylic acid compound (CA1) was changed to L-arginine (CA2) as the carboxylic acid compound. As in Example 1, the recovered zirconium oxide was a syrup-like viscous liquid. The change in properties indicates that a coating agent was attached to the surface of the zirconium oxide.

The resulting syrup-like surface-modified zirconium oxide was used to evaluate the dispersion stability in the same manner as in Example 1.
In an evaluation of the dispersion stability in an organic solvent, the zirconium oxide fine particles remained stably dispersed even after the metal oxide fine particle dispersion was allowed to stand at room temperature for 90 days.
In both the evaluation of dispersion stability in a (meth)acrylic resin-containing composition and the evaluation of dispersion stability in a composition containing a curable aromatic compound, the zirconium oxide microparticles remained stably dispersed even when the metal oxide microparticle dispersion was allowed to stand at room temperature for 30 days.
A comparison of Examples 1 to 3 and Example 10 with Example 12 shows that the dispersion stability of zirconium oxide microparticles in an organic solvent was improved by coating with a carboxylic acid compound (CA2) in the presence of N,N,N',N'-tetramethylurea, a compound having an amide structure.

Example 13
50 parts by mass of zirconium oxide having a carboxylic acid compound (CA1) attached thereto obtained by coating treatment in the same manner as in Example 5, and 18 parts by mass of a copolymer of 40% by mass of 4-hydroxyphenyl methacrylate and 60% by mass of glycidyl methacrylate were dispersed in 50 parts by mass of methyl isobutyl ketone to obtain a metal oxide fine particle dispersion.
The weight average molecular weight of the copolymer was 6,000.
The obtained dispersion of metal oxide fine particles was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed.

Example 14
A metal oxide microparticle dispersion was obtained in the same manner as in Example 13, except that the copolymer was changed to a copolymer of 72% by mass of 4-oxatetracyclo-[6.2.1.0 ^2,7 0 ^3,5 ]undecanyl acrylate, 18% by mass of methacrylic acid, and 10% by mass of tricyclodecyl methacrylate.
The weight average molecular weight of the above copolymer was 10,000.
The obtained dispersion of metal oxide fine particles was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed.

Example 15
Further, a metal oxide fine particle dispersion was obtained in the same manner as in Example 13, except that 2 parts by mass of 1,2-naphthoquinone diazide-5-sulfonic acid ester (3 moles) of 4-[2-[4-[1,1 bis(4-hydroxyphenyl)ethyl]phenyl]propan-2-yl]phenol, which is a photosensitizer, was added and the solid content concentration of the metal oxide fine particle dispersion was adjusted to 20% by mass by dilution with methyl isobutyl ketone. The obtained metal oxide fine particle dispersion can be used as a positive photosensitive composition.
The obtained dispersion of metal oxide fine particles was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed.

The obtained metal oxide fine particle dispersion was applied to a glass substrate using a spin coater. After pre-baking the coating film at 110°C for 120 seconds, the coating film was exposed to broadband light through a mask for a line and space pattern with a line width of 20 μm and a space width of 20 μm using an ultraviolet curing machine. The exposed coating film was developed in an alkaline developer at 26°C. As the developer, a mixed aqueous solution of NaOH/Na ₂ CO ₃ with a concentration of 0.825% by mass was used. After rinsing with pure water, unnecessary parts in the exposed coating film were removed. Thereafter, the developed coating film was post-baked at 230°C for 20 minutes to form a patterned coating film.

Example 16
Furthermore, a metal oxide fine particle dispersion was obtained in the same manner as in Example 15, except that 9 mass parts of dipentaerythritol hexaacrylate, a photopolymerizable compound, was added, and 2 parts by mass of 1,2-naphthoquinone diazide-5-sulfonic acid ester (3 moles) of 4-[2-[4-[1,1 bis(4-hydroxyphenyl)ethyl]phenyl]propan-2-yl]phenol was changed to 2 parts by mass of a compound having the following structure, which is a photopolymerization initiator. The obtained metal oxide fine particle dispersion can be used as a negative photosensitive composition.
The obtained dispersion of metal oxide fine particles was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed.

The obtained metal oxide microparticle dispersion was applied onto a glass substrate using a spin coater. The coating film was prebaked at 90°C for 120 seconds to form a coating film with a thickness of 1.0 μm. Next, the coating film was exposed to broadband light using an ultraviolet curing machine through a mask for a line and space pattern with a line width of 20 μm and a space width of 20 μm. The exposed coating film was developed with a 2.38% by mass TMAH (tetramethylammonium hydroxide) aqueous solution at 23°C to remove unnecessary portions. The developed coating film was then postbaked at 230°C for 20 minutes to form a patterned cured film.

Example 17
A metal oxide fine particle dispersion was obtained in the same manner as in Example 16, except that the photopolymerization initiator was changed to a compound having the following structure. The obtained metal oxide fine particle dispersion can be used as a negative photosensitive composition.
The obtained dispersion of metal oxide fine particles was allowed to stand at room temperature for 30 days, whereupon the zirconium oxide fine particles remained stably dispersed.
In addition, the obtained metal oxide microparticle dispersion was used to form a patterned cured film by photolithography in the same manner as in Example 16, and as a result, a well-patterned cured film was formed, as in Example 16.

Claims (13)

At least a part of the surface of the metal oxide fine particles is treated with the following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a monovalent organic group, ^R1 and ^R2 are bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1). The method for producing surface-modified metal oxide fine particles according to claim 1, wherein the coating with the carboxylic acid compound and/or the carboxylate is carried out on modified metal oxide fine particles prepared in a solution or suspension containing a compound having an amide structure or dispersed in the presence of a dispersion medium containing a compound having an amide structure. 3. The method for producing surface-modified metal oxide fine particles according to claim 1, wherein in the formula (1), ^R1 and ^R2 are bonded to each other to form an imidazole ring. The method for producing surface-modified metal oxide microparticles according to any one of claims 1 to 3, wherein the metal oxide microparticles contain at least one metal element selected from the group consisting of Ag, Cu, In, Sn, Ti, Hf, Al, Zr, Zn, and Ce. A method for producing modified metal oxide microparticles, comprising preparing metal oxide microparticles in a solution or suspension containing a compound having an amide structure, or dispersing metal oxide microparticles in the presence of a dispersion medium containing a compound having an amide structure,
The following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a monovalent organic group, ^R1 and ^R2 are bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1). The method for producing modified metal oxide microparticles according to claim 5, wherein the metal oxide microparticles contain at least one metal element selected from the group consisting of Ag, Cu, In, Sn, Ti, Hf, Al, Zr, Zn, and Ce. 7. The method for producing modified metal oxide fine particles according to claim 5, wherein in said formula (1), said ^R1 and said ^R2 are bonded to each other to form an imidazole ring. At least a portion of the surface is represented by the following formula (1):

(In formula (1), ^R1 and ^R2 are each independently a monovalent organic group, ^R1 and ^R2 are bonded to each other to form a ring, and the ring may contain one or more elements selected from the group consisting of N, S, and O as ring-constituting elements, ^R3 is a monovalent organic group, and ^R4 is a methylene group or a single bond.)
and/or a carboxylate derived from a carboxylic acid compound represented by formula (1). The surface-modified metal oxide fine particles according to claim 8 , wherein in said formula (1), said R ¹ and said R ² are bonded to each other to form an imidazole ring. The surface-modified metal oxide microparticles according to claim 8 or 9, which contain at least one metal element selected from the group consisting of Ag, Cu, In, Sn, Ti, Hf, Al, Zr, Zn, and Ce. A metal oxide fine particle dispersion liquid containing the surface-modified metal oxide fine particles described in any one of claims 8 to 10 as the metal oxide (A). The metal oxide fine particle dispersion liquid according to claim 11, comprising a base component (B),
The metal oxide microparticle dispersion liquid, wherein the base material component (B) is a resin material consisting of a polymer compound, a thermosetting material which hardens by crosslinking upon heating to produce a polymer compound or by causing intramolecular cyclization upon heating, a photopolymerizable compound which can be hardened by exposure to light, or a hydrolytic condensation silane compound which undergoes hydrolytic condensation due to moisture in the composition or in the atmosphere. The base component (B) is represented by the following formula (b-01):

In formula (b-01), W ⁰¹ and W ⁰² each independently represent the following formula (b-02):

is a group represented by
In formula (b-02), ring Z ⁰¹ represents an aromatic hydrocarbon ring; X ⁰¹ represents a single bond or a group represented by -S-; R ⁰¹ represents a single bond, an alkylene group having from 1 to 4 carbon atoms, or an alkyleneoxy group having from 1 to 4 carbon atoms; when R ⁰¹ is an alkyleneoxy group, an oxygen atom in the alkyleneoxy group is bonded to ring Z ⁰¹ ; R ⁰¹ represents a monovalent hydrocarbon group, a hydroxyl group, a group represented by -OR ^4A , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a mercapto group, a carboxy group, an amino group, a carbamoyl group, a group represented by -NHR ^4C , a group represented by -N(R ^4D ) ₂ , a sulfo group, or a monovalent hydrocarbon group, a group represented by -OR ^4A , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, -NHR at least a portion of the hydrogen atoms bonded to carbon atoms contained in the group represented by ^-N (R ^{4D ) 2 or the group represented by -N(R 4D} _{) 2} are substituted with a monovalent hydrocarbon group, a hydroxyl group, a group represented by -OR ^4a , a group represented by -SR ^4B , an acyl group, an alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, a mercapto group, a carboxyl group, an amino group, a carbamoyl group, a group represented by -NHR ^4C , a group represented by -N(R ^4D ) ₂ , a mesyloxy group, or a sulfo group; R ^4A to R ^4D each independently represent a monovalent hydrocarbon group; M represents an integer of 0 or greater; and R ⁰³ represents a hydrogen atom, a vinyl group, a thiirane-2-ylmethyl group, a glycidyl group, or a (meth)acryloyl group;
Both W ⁰¹ and W ⁰² do not have a hydrogen atom as R ⁰³ ;
Ring Y ⁰¹ and ring Y ⁰² are the same or different aromatic hydrocarbon rings; R ⁰⁰ is a single bond, a methylene group which may have a substituent, an ethylene group which may have a substituent and which may contain a heteroatom between the two carbon atoms, a group represented by -O-, a group represented by -NH-, or a group represented by -S-; R ^3A and R ^3B are independently a cyano group, a halogen atom, or a monovalent hydrocarbon group; and N1 and N2 are independently an integer of 0 to 4.
The metal oxide fine particle dispersion liquid according to claim 12, comprising a compound represented by the formula: