JP2024085734A - Composition and photosensitive composition - Google Patents

Abstract

The present invention provides a composition that provides a cured film with reduced unevenness, a photosensitive composition, a cured product of the photosensitive composition, and a method for producing a cured film using the photosensitive composition.
[Solution] A composition comprising a photopolymerizable compound (A) and inorganic fine particles (B), wherein the photopolymerizable compound (A) comprises an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure.
[Selection diagram] None

Description

The present invention relates to a composition containing a photopolymerizable compound (A) and inorganic fine particles (B), a photosensitive composition, a cured product of the photosensitive composition, and a method for producing a cured film using the photosensitive composition.

High refractive index materials have been used for forming optical members, such as compositions in which particles of metal oxides, such as titanium oxide or zirconium oxide, are dispersed in an organic component.
As a composition for forming such a highly refractive material, an energy ray-curable composition containing a metal oxide (A) having a specific particle size, a (meth)acrylate (B), and a photopolymerization initiator (C) has been proposed (see Patent Document 1).

JP 2017-214465 A

In photosensitive compositions such as those described in Patent Document 1, a multifunctional (meth)acrylate compound may be used to increase sensitivity and form a good cured film. However, when a photosensitive composition using a multifunctional (meth)acrylate compound is applied by inkjet printing, there is a problem that unevenness is likely to occur in the cured film.

The present invention has been made in consideration of the above problems, and aims to provide a composition that gives a cured film with reduced unevenness, a photosensitive composition, a cured product of the photosensitive composition, and a method for producing a cured film using the photosensitive composition.

The present inventors have found that the above problems can be solved by using a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure together with an aromatic ring-containing polymerizable compound (A1) as the photopolymerizable compound (A) in a composition containing a photopolymerizable compound (A) and inorganic fine particles (B), or in a photosensitive composition containing a photopolymerizable compound (A), inorganic fine particles (B), and an initiator (C), and have thus completed the present invention. Specifically, the present invention provides the following.

[1] A photopolymerizable compound (A) and inorganic fine particles (B),
The composition, wherein the photopolymerizable compound (A) comprises an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure.

[2] The composition described in [1], in which the polymerizable compound (A2) is a (meth)acrylate compound having a hyperbranched structure or a dendrimer structure.

[3] The composition according to [1] or [2], wherein the aromatic ring-containing polymerizable compound (A1) is at least one selected from the group consisting of a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), and a compound represented by the following formula (A1-4):
R ^a101 - (X ^a103 -X ^a102 ) _ma12 - (X ^a101 ) _ma11 - Ar ^a101 - ( (X ^a104 ) _ma13 - (X ^a105 ) ) _ma14 ... (A1-1)
(In formula (A1-1), Ar ^a101 is an aromatic group having 7 to 12 carbon atoms and a valence of (ma14+1), which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a101 is a radical polymerizable group-containing group or a cationically polymerizable group-containing group; X ^a101 is O or S; X ^a102 is an alkylene group which may be interrupted by one or more O and/or S; X ^a103 is O or S; X ^a104 is O or S; X ^a105 is an alkyl group which may be interrupted by one or more O and/or S; ma11 is 0 or 1; ma12 is 0 or 1; ma13 is 0 or 1; ma14 is an integer of 0 or greater; X ^a101 , X ^a103 , and X The total number of O and/or S as ^a104 and the number of O and/or S contained in X ^a102 and X ^a105 is 3 or more.
R ^a201 -X ^a203 -R ^a202 -(X ^a201 ) _{m a21} -Ph ²¹ -S-Ph ²² -(X ^a202 ) _{m a22} -R ^a204 -X ^a204 -R ^a203 ... (A1-2)
(In formula (A1-2), R ^a201 and R ^a203 are each independently a radical polymerizable group-containing group or a cationically polymerizable group-containing group, R ^a202 and R ^a204 are each independently an alkylene group which may be interrupted by one or more O and/or S, X ^a201 , X ^a202 , X ^a203 and X ^a204 are each independently O or S, Ph ²¹ and Ph ²² are each independently a phenylene group which may be substituted with an alkyl group having 1 to 5 carbon atoms, ma21 is 0 or 1, ma22 is 0 or 1, and the compound represented by formula (A1-2) does not simultaneously have a radical polymerizable group-containing group and a cationically polymerizable group-containing group.)
R ^a301 -R ^a302 -X ^a301 -Ph ³¹ -CO-O-R ^a303 ... (A1-3)
(In formula (A1-3), R ^a301 is a radically polymerizable group-containing group or a cationically polymerizable group-containing group, X ^a301 is O or S, R ^a302 is a single bond or a divalent linking group, R ^a303 is a benzyl group or a phenethyl group, and Ph ³¹ is a phenylene group.)
(R ^a401 -X ^a401 -R ^a402 ) _ma41 -Ar ^a401 -C(=O)-Ar ^a402 -(R ^a403 -X ^a402 -R ^a404 ) _ma42 ... (A1-4)
In formula (A1-4), Ar ^a401 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma41+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; Ar ^a402 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma42+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a401 and R ^a404 are each independently a radical polymerizable group-containing group or a cation polymerizable group-containing group; X ^a401 and X ^a402 are each independently O or S; R ^a402 and R Each ^a403 is independently an alkylene group, ma41 is an integer of 1 or more and 3 or less, and ma42 is an integer of 0 or more and 3 or less.

[4] The inorganic fine particles (B) contain metal oxide fine particles (B1),
The composition according to any one of [1] to [3], wherein the metal oxide fine particles (B1) include at least one selected from the group consisting of titanium oxide fine particles, zirconium oxide fine particles, and niobium oxide fine particles.

[5] A solvent (S),
The composition according to any one of [1] to [4], which is used as an ink-jet ink.

[6] A composition comprising a photopolymerizable compound (A), inorganic fine particles (B), and an initiator (C),
The photosensitive composition, wherein the photopolymerizable compound (A) comprises an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure.

[7] A cured product of the photosensitive composition described in [6].

[8] Coating the photosensitive composition according to [6] on a substrate to form a coating film;
exposing the coating film to light;
A method for producing a cured film comprising the steps of:

[9] The method for producing a cured film according to [8], in which the photosensitive composition is applied by an inkjet printing method.

The present invention provides a composition that provides a cured film with reduced unevenness, a photosensitive composition, a cured product of the photosensitive composition, and a method for producing a cured film using the photosensitive composition.

<Composition>
The composition contains a photopolymerizable compound (A) and inorganic fine particles (B). Such a composition is essentially an inorganic fine particle dispersion composition, and is used to form a functional material having properties according to the type of inorganic fine particles (B) after appropriately blending an initiator for curing the photopolymerizable compound (A).
The photopolymerizable compound (A) contains an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure.
The composition contains the polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure in addition to the aromatic ring-containing polymerizable compound (A1), and thus provides a cured film with reduced unevenness.
The following describes essential and optional components that the composition may contain.

<Photopolymerizable Compound (A)>
The composition contains a photopolymerizable compound (A). The photopolymerizable compound (A) is a compound having a radical polymerizable group-containing group or a cationically polymerizable group-containing group.

The radical polymerizable group-containing group typically includes a group containing an ethylenically unsaturated double bond. As the ethylenically unsaturated double bond-containing group, a vinyl group or an alkenyl group-containing group including an alkenyl group such as an allyl group is preferable, and a (meth)acryloyl group-containing group is more preferable.
The cationic polymerizable group-containing group typically includes an epoxy group-containing group, an oxetanyl group-containing group, a vinyloxy group-containing group, and a vinylthio group-containing group. Among these, the epoxy group-containing group and the vinyloxy group-containing group are preferred. As the epoxy group-containing group, an alicyclic epoxy group-containing group and a glycidyl group are preferred. Note that the alicyclic epoxy group is an aliphatic cyclic group in which two carbon atoms as adjacent ring constituent atoms in the aliphatic cyclic group are bonded via an oxygen atom. In other words, the alicyclic epoxy group has an epoxy group containing a three-membered ring consisting of two carbon atoms and one oxygen atom on the aliphatic ring.

In the specification and claims of this application, (meth)acrylic means both acrylic and methacrylic, (meth)acryloyl means both acryloyl and methacryloyl, and (meth)acrylate means both acrylate and methacrylate.

[Aromatic Ring-Containing Polymerizable Compound (A1)]
As described above, the photopolymerizable compound (A) contains an aromatic ring-containing polymerizable compound (A1).
In the aromatic ring-containing polymerizable compound (A1), the total number of radically polymerizable group-containing groups and cationic polymerizable group-containing groups in one molecule is not particularly limited, but is, for example, 6 or less, 4 or less, or 2 or less.

Examples of the aromatic ring contained in the aromatic ring-containing polymerizable compound (A1) include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a biphenyl ring; and aromatic heterocycles such as a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring. Among these, aromatic hydrocarbon rings are preferred, and a benzene ring and a biphenyl ring are more preferred.

In the aromatic ring-containing polymerizable compound (A1), the total number of O atoms and S atoms in one molecule is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. The upper limit of the total is not particularly limited, but is, for example, 10.

From the viewpoint of more easily achieving the effects of the present invention, the aromatic ring-containing polymerizable compound (A1) is preferably at least one selected from the group consisting of a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), and a compound represented by the following formula (A1-4).

In the specification of this application, the compound represented by formula (A1-1) is also referred to as "compound (A1-1)", the compound represented by formula (A1-2) is also referred to as "compound (A1-2)", the compound represented by formula (A1-3) is also referred to as "compound (A1-3)", and the compound represented by formula (A1-4) is also referred to as "compound (A1-4)".

[Compound (A1-1)]
R ^a101 - (X ^a103 -X ^a102 ) _ma12 - (X ^a101 ) _ma11 - Ar ^a101 - ( (X ^a104 ) _ma13 - (X ^a105 ) ) _ma14 ... (A1-1)
(In formula (A1-1), Ar ^a101 is an aromatic group having 7 to 12 carbon atoms and a valence of (ma14+1), which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a101 is a radical polymerizable group-containing group or a cationically polymerizable group-containing group; X ^a101 is O or S; X ^a102 is an alkylene group which may be interrupted by one or more O and/or S; X ^a103 is O or S; X ^a104 is O or S; X ^a105 is an alkyl group which may be interrupted by one or more O and/or S; ma11 is 0 or 1; ma12 is 0 or 1; ma13 is 0 or 1; ma14 is an integer of 0 or greater; X ^a101 , X ^a103 , and X The total number of O and/or S as ^a104 and the number of O and/or S contained in X ^a102 and X ^a105 is 3 or more.

In formula (A1-1), Ar ^a101 is a (ma14+1)-valent aromatic group having 7 to 12 carbon atoms and which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom.
The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group.
Examples of the aromatic group include groups obtained by removing (ma14+1) hydrogen atoms from aromatic hydrocarbons such as naphthalene and biphenyl, and groups obtained by removing (ma14+1) hydrogen atoms from aromatic heterocyclic compounds such as quinoline, isoquinoline, quinoxaline, cinnoline, quinazoline, phthalazine, naphthyridine, benzoxazole, benzothiazole, benzimidazole, indole, benzofuran, benzothiophene, isoindole, and isobenzofuran.

The aromatic group represented by Ar ^a101 may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 5 carbon atoms, a cyano group, and a halogen atom.
The number of substituents bonded to the aromatic group represented by Ar ^a101 is not particularly limited.
Examples of the alkyl group having 1 to 5 carbon atoms 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 neopentyl group, a sec-pentyl group, and a tert-pentyl group. Of these groups, a methyl group and an ethyl group are preferred.
Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.
As the aromatic group represented by Ar ^a101 described above, groups in which (ma14+1) hydrogen atoms have been removed from naphthalene, biphenyl, quinoline, and benzothiazole are preferred.
When it is desired to impart a high refractive index to a material formed using the composition, the aromatic group represented by Ar ^a101 is preferably substituted with a cyano group.

R ^a101 is a radical polymerizable group-containing group or a cationic polymerizable group-containing group. The radical polymerizable group and the cationic polymerizable group are as described above. The radical polymerizable group as R ^a101 is preferably a (meth)acryloyl group-containing group, more preferably a (meth)acryloyl group. The cationic polymerizable group as R ^a101 is preferably a vinyl group, a vinyloxy group-containing group, or an epoxy group-containing group, more preferably a vinyl group or an epoxy group-containing group, and is preferably an alicyclic epoxy group-containing group or a glycidyl group.
A vinyl group is generally a radically polymerizable group, but in formula (A1-1), when R ^a101 is a vinyl group, the vinyl group forms a cationically polymerizable group, that is, a vinyloxy group or a vinylthio group, together with X ^a103 which is O or S. For this reason, in formula (A1-1), the vinyl group as R ^a101 is a cationically polymerizable group, not a radically polymerizable group.

X ^a102 is an alkylene group which may be interrupted by one or more O and/or S. X ^a102 is preferably an alkylene group interrupted by one or more O and/or S.
X ^a105 is an alkyl group which may be interrupted by one or more O and/or S. X ^a105 is preferably an alkyl group interrupted by one or more O and/or S.
The number of carbon atoms in the alkylene group which may be interrupted by one or more O and/or S as ^Xa102 and the alkyl group which may be interrupted by one or more O and/or S as ^Xa105 are each not particularly limited as long as the desired effect is not impaired.

The alkylene group as ^Xa102 which may be interrupted by one or more O and/or S, and the alkyl group as ^Xa105 which may be interrupted by one or more O and/or S, are each preferably a group consisting of ma aliphatic chain saturated hydrocarbon groups selected from an alkylene group having from 1 to 4 carbon atoms, an alkanetriyl group having from 1 to 4 carbon atoms, and an alkyl group having from 1 to 4 carbon atoms, and (ma-1) O and/or S linking the ma aliphatic chain saturated hydrocarbon groups.
Here, ma is an integer between 2 and 6.

Suitable examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, and a butane-1,4-diyl group. Of these groups, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, and a propane-1,3-diyl group are preferred.
Preferred examples of the alkanetriyl group having 1 to 4 carbon atoms include a propane-1,2,3-triyl group, a butane-1,2,3-triyl group, and a butane-1,2,4-triyl group. Of these groups, a propane-1,2,3-triyl group is preferred.
Preferred examples of the alkyl group having 1 to 4 carbon atoms 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, and a tert-butyl group. Among these groups, a methyl group and an ethyl group are preferred.

The alkylene group optionally interrupted by one or more O and/or S as X ^a102 is preferably a group consisting of ma alkylene groups having 1 to 4 carbon atoms and (ma-1) O and/or S linking the ma alkylene groups.
The alkyl group, which may be interrupted by one or more O and/or S, as X ^a105 is preferably a group consisting of (ma-1) alkylene groups having from 1 to 4 carbon atoms, one alkyl group having from 1 to 4 carbon atoms, and (ma-1) O and/or S linking the (ma-1) alkylene groups having from 1 to 4 carbon atoms and the one alkyl group having from 1 to 4 carbon atoms.
Here, ma is an integer between 2 and 6.

Preferable specific examples of the alkylene group which may be interrupted by one or more O and/or S, as X ^a102 , include the following groups.
-CH2CH2 _{- O - CH2CH2-}
-( _{CH2CH2 -} O) _{2 - CH2CH2-}
-( _{CH2CH2 -} O) _{3 - CH2CH2-}
-( _{CH2CH2 -} O) _{4 - CH2CH2-}
-( _{CH2CH2 -} O) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -O-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₅ -C( _CH3 ) _{HCH2-
--CH2CH2CH2 - O - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - O} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{5 - CH2CH2CH2-}
-CH2C( _{OCH3 ) HCH2-
-CH2C} ( _{OCH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH2CH3 ) HCH2- ​}
-CH2CH2 _{- S - CH2CH2-}
-( _{CH2CH2 -} S) _{2 - CH2CH2-}
-( _{CH2CH2 -} S) _{3 - CH2CH2-}
-( _{CH2CH2 -} S) _{4 - CH2CH2-}
-( _{CH2CH2 -} S) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -S-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₅ -C( _CH3 ) _{HCH2-
-CH2CH2CH2 - S - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - S} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{5 - CH2CH2CH2-}
-CH2C( _{SCH3 ) HCH2-
-CH2C} ( _{SCH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH2CH3 ) HCH2- ​}

Among these groups,
-CH2CH2 _{- O - CH2CH2-} ,
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,
-CH2CH2CH2 - O - CH2CH2CH2- ,}
-CH2CH2 _{- S - CH2CH2-} ,
-( _{CH2CH2 -} S) _{2 -CH2CH2- and} -( _{CH2CH2 -} S) _{3 -CH2CH2- are} preferred,
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,}
--(CH ₂ CH ₂ --S) ₂ --CH ₂ CH ₂ -- and --(CH ₂ CH ₂ --S) ₃ --CH ₂ CH ₂ -- are more preferred.

Preferable specific examples of the alkylene group which may be interrupted by one or more O and/or S, as X ^a105 , include the following groups.
-CH2CH2 _{- O} - _CH3
-CH2CH2 _{- O - CH2CH3}
-( _{CH2CH2 -} O) ₂ - _CH3
-( _{CH2CH2 -} O) _{2 - CH2CH3}
-( _{CH2CH2 -} O) ₃ - _CH3
-( _{CH2CH2 -} O) _{3 - CH2CH3}
-( _{CH2CH2 -} O) ₄ - _CH3
-( _{CH2CH2 -} O) _{4 - CH2CH3}
-( _{CH2CH2 -} O) ₅ - _CH3
-( _{CH2CH2 -} O) _{5 - CH2CH3}
-C( _CH3 ) _HCH2 -O- _CH3
-C( _CH3 ) _HCH2 -O _{- CH2CH3}
-(C( _CH3 ) _HCH2 -O) ₂ - _CH3
-(C( _CH3 ) _HCH2 -O) _{2 - CH2CH3}
-(C( _CH3 ) _HCH2 -O) ₃ - _CH3
-(C( _CH3 ) _HCH2 -O) _{3 - CH2CH3}
-(C( _CH3 ) _HCH2 -O) ₄ - _CH3
-(C( _CH3 ) _HCH2 -O) _{4 - CH2CH3}
-(C( _CH3 ) _HCH2 -O) ₅ - _CH3
-(C( _CH3 ) _HCH2 -O) _{5 - CH2CH3
-CH2C} ( _CH3 )H-O- _CH3
-CH2C ( _CH3 )H-O _{- CH2CH3}
-( _CH2C ( _CH3 )H-O) ₂ - _CH3
-( _CH2C ( _CH3 )H-O) _{2 - CH2CH3}
-( _CH2C ( _CH3 )H-O) ₃ - _CH3
-( _CH2C ( _CH3 )H-O) _{3 - CH2CH3}
-( _CH2C ( _CH3 )H-O) ₄ - _CH3
-( _CH2C ( _CH3 )H-O) _{4 - CH2CH3}
-( _CH2C ( _CH3 )H-O) ₅ - _CH3
-( _CH2C ( _CH3 )H-O) _{5 - CH2CH3}
-CH2CH2 _{- S} - _CH3
-CH2CH2 _{- S - CH2CH3}
-( _{CH2CH2 -} S) ₂ - _CH3
-( _{CH2CH2 -} S) _{2 - CH2CH3}
-( _{CH2CH2 -} S) ₃ - _CH3
-( _{CH2CH2 -} S) _{3 - CH2CH3}
-( _{CH2CH2 -} S) ₄ - _CH3
-( _{CH2CH2 -} S) _{4 - CH2CH3}
-( _{CH2CH2 -} S) ₅ - _CH3
-( _{CH2CH2 -} S) _{5 - CH2CH3}
-C( _CH3 ) _HCH2 -S- _CH3
-C( _CH3 )HCH2 _- S _{- CH2CH3}
-(C( _CH3 ) _HCH2 -S) ₂ - _CH3
-(C( _CH3 ) _HCH2 -S) _{2 - CH2CH3}
-(C( _CH3 ) _HCH2 -S) ₃ - _CH3
-(C( _CH3 ) _HCH2 -S) _{3 - CH2CH3}
-(C( _CH3 ) _HCH2 -S) ₄ - _CH3
-(C( _CH3 ) _HCH2 -S) _{4 - CH2CH3}
-(C( _CH3 ) _HCH2 -S) ₅ - _CH3
-(C( _CH3 ) _HCH2 -S) _{5 - CH2CH3
-CH2C} ( _CH3 )H-S- _CH3
-CH2C ( _CH3 )H-S _{- CH2CH3}
-( _CH2C ( _CH3 )H-S) ₂ - _CH3
-( _CH2C ( _CH3 )H-S) _{2 - CH2CH3}
-( _CH2C ( _CH3 )H-S) ₃ - _CH3
-( _CH2C ( _CH3 )H-S) _{3 - CH2CH3}
-( _CH2C ( _CH3 )H-S) ₄ - _CH3
-( _CH2C ( _CH3 )H-S) _{4 - CH2CH3}
-( _CH2C ( _CH3 )H-S) ₅ - _CH3
-( _CH2C ( _CH3 )H-S) _{5 - CH2CH3}

In formula (A1-1), X ^a103 is O or S, and X ^a104 is O or S.

In formula (A1-1), ma11 is 0 or 1, ma12 is 0 or 1, ma13 is 0 or 1, and ma14 is an integer of 0 or greater.
It is preferable that ma11 and ma12 are both 1, since the desired effect can be easily obtained by using the compound (A1-1).
The upper limit of ma14 is not particularly limited. The value of ma14 is appropriately determined in consideration of the structure of the aromatic group as Ar ^a101 . The value of ma14 is preferably 0 or more and 2 or less, more preferably 0 or 1. In view of the ease of availability and synthesis of the compound (A1-1), ma14 is preferably 0.

In formula (A1-1), the total number of O and/or S as X ^a101 , X ^a103 and X ^a104 and the number of O and/or S contained in X ^a102 and X ^a105 is 3 or more.
When the compound (A1-1) contains O and/or S in a specific amount or more in a specific portion, excessive loss in weight of components other than the solvent when the composition is heated can be suppressed, and dispersion of the inorganic fine particles (B) in the composition can be stabilized.
There is no particular upper limit on the total number of O and/or S as ^Xa101 , ^Xa103 , and ^Xa104 , and the total number of O and/or S contained in ^Xa102 and ^Xa105 , as long as the desired effect is not impaired.
The total number of O and/or S as ^Xa101 , ^Xa103 , and ^Xa104 and the number of O and/or S contained in ^Xa102 and ^Xa105 is, for example, preferably 3 or more and 10 or less, more preferably 4 or more and 8 or less, and even more preferably 4 or more and 6 or less.

Preferable specific examples of the compound (A1-1) include the following compounds.
In the following compounds, the linking group linking an acryloyloxy group or a methacryloyloxy group with an aryloxy group, an arylthio group, a heteroaryloxy group or a heteroarylthio group is -CH ₂ CH ₂ -O-CH ₂ CH ₂ -, -(CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₂ -, -(CH ₂ CH ₂ -O) ₃ -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH ₂ CH ₂ -,
Compounds in which the substituent is changed to --(CH ₂ CH ₂ --S) ₂ --CH ₂ CH ₂ -- or --(CH ₂ CH ₂ --S) ₃ --CH ₂ CH ₂ -- are also preferred as compound (A1-1).

[Compound (A1-2)]
R ^a201 -X ^a203 -R ^a202 -(X ^a201 ) _{m a21} -Ph ²¹ -S-Ph ²² -(X ^a202 ) _{m a22} -R ^a204 -X ^a204 -R ^a203 ... (A1-2)
(In formula (A1-2), R ^a201 and R ^a203 are each independently a radical polymerizable group-containing group or a cationically polymerizable group-containing group, R ^a202 and R ^a204 are each independently an alkylene group which may be interrupted by one or more O and/or S, X ^a201 , X ^a202 , X ^a203 and X ^a204 are each independently O or S, Ph ²¹ and Ph ²² are each independently a phenylene group which may be substituted with an alkyl group having 1 to 5 carbon atoms, ma21 is 0 or 1, ma22 is 0 or 1, and the compound represented by formula (A1-2) does not simultaneously have a radical polymerizable group-containing group and a cationically polymerizable group-containing group.)

In formula (A1-2), Ph ²¹ and Ph ²² each independently represent a phenylene group which may be substituted with an alkyl group having from 1 to 5 carbon atoms. The phenylene group represented by Ph ²¹ and Ph ²² may be any one of an o-phenylene group, an m-phenylene group, and a p-phenylene group, and is preferably a p-phenylene group.

The number of alkyl groups as substituents bonded to the phenylene groups as Ph ²¹ and Ph ²² is not particularly limited.
Examples of the alkyl group having 1 to 5 carbon atoms 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 neopentyl group, a sec-pentyl group, and a tert-pentyl group. Of these groups, a methyl group and an ethyl group are preferred.

R ^a201 and R ^a203 are each independently a radical polymerizable group-containing group or a cationic polymerizable group-containing group. The radical polymerizable group and cationic polymerizable group are as described above. The radical polymerizable group-containing group of R ^a201 and R ^a203 is preferably a (meth)acryloyl group-containing group, more preferably a (meth)acryloyl group. The cationic polymerizable group-containing group of R ^a201 and R ^a203 is preferably a vinyl group, a vinyloxy group-containing group, and an epoxy group-containing group, more preferably a vinyl group and an epoxy group-containing group, and is preferably an alicyclic epoxy group-containing group and a glycidyl group.
A vinyl group is generally a radically polymerizable group, but in formula (A1-2), when R ^a201 and R ^a203 are vinyl groups, the vinyl groups form cationically polymerizable groups, that is, vinyloxy groups or vinylthio groups, together with X ^a203 or X ^a204 which is O or S. For this reason, in formula (A1-2), the vinyl groups as R ^a201 and R ^a203 are cationically polymerizable groups, not radically polymerizable groups.

R ^a202 and R ^a204 are each independently an alkylene group which may be interrupted by one or more O and/or S. R ^a202 and R ^a204 may be an alkylene group or an alkylene group interrupted by one or more O and/or S.
The number of carbon atoms of the alkylene group, which may be interrupted by one or more O and/or S, represented by R ^a202 and R ^a204 is not particularly limited as long as the desired effect is not impaired. When R ^a202 and R ^a204 are alkylene groups, the number of carbon atoms of the alkylene group is, for example, 1 or more and 10 or less, or 1 or more and 4 or less.

The alkylene group which may be interrupted by one or more O and/or S as R ^a202 and R ^a204 is preferably a group consisting of ma aliphatic chain saturated hydrocarbon groups selected from an alkylene group having 1 to 4 carbon atoms, an alkanetriyl group having 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms, and (ma-1) O and/or S linking the ma aliphatic chain saturated hydrocarbon groups.
Here, ma is an integer between 2 and 6.

Suitable examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, and a butane-1,4-diyl group. Of these groups, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, and a propane-1,3-diyl group are preferred.
Preferred examples of the alkanetriyl group having 1 to 4 carbon atoms include a propane-1,2,3-triyl group, a butane-1,2,3-triyl group, and a butane-1,2,4-triyl group. Of these groups, a propane-1,2,3-triyl group is preferred.
Preferred examples of the alkyl group having 1 to 4 carbon atoms 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, and a tert-butyl group. Of these groups, a methyl group and an ethyl group are preferred.

The alkylene group optionally interrupted by one or more O and/or S as R ^a202 and R ^a204 is preferably a group consisting of ma alkylene groups having 1 to 4 carbon atoms and (ma-1) O and/or S linking the ma alkylene groups.
Here, ma is an integer between 2 and 6.

Preferable specific examples of the alkylene group which may be interrupted by one or more O and/or S as R ^a202 and R ^a204 include the following groups.
_{-CH2-
-CH2CH2- ​
-CH2CH2CH2- ​ ​}
-CH2CH2 _{- O - CH2CH2-}
-( _{CH2CH2 -} O) _{2 - CH2CH2-}
-( _{CH2CH2 -} O) _{3 - CH2CH2-}
-( _{CH2CH2 -} O) _{4 - CH2CH2-}
-( _{CH2CH2 -} O) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -O-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₅ -C( _CH3 ) _{HCH2-
--CH2CH2CH2 - O - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - O} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{5 - CH2CH2CH2-}
-CH2C( _{OCH3 ) HCH2-
-CH2C} ( _{OCH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH2CH3 ) HCH2- ​}
-CH2CH2 _{- S - CH2CH2-}
-( _{CH2CH2 -} S) _{2 - CH2CH2-}
-( _{CH2CH2 -} S) _{3 - CH2CH2-}
-( _{CH2CH2 -} S) _{4 - CH2CH2-}
-( _{CH2CH2 -} S) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -S-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₅ -C( _CH3 ) _{HCH2-
-CH2CH2CH2 - S - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - S} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{5 - CH2CH2CH2-}
-CH2C( _{SCH3 ) HCH2-
-CH2C} ( _{SCH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH2CH3 ) HCH2- ​}

Among these groups,
_-CH2-
-CH2CH2 _{- O - CH2CH2-} ,
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,
-CH2CH2CH2 - O - CH2CH2CH2- ,}
-CH2CH2 _{- S - CH2CH2-} ,
-( _{CH2CH2 -} S) _{2 -CH2CH2- and} -( _{CH2CH2 -} S) _{3 -CH2CH2- are} preferred,
_-CH2-
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,}
--(CH ₂ CH ₂ --S) ₂ --CH ₂ CH ₂ -- and --(CH ₂ CH ₂ --S) ₃ --CH ₂ CH ₂ -- are more preferred.

In formula (A1-2), X ^a201 , X ^a202 , X ^a203 , and X ^a204 each independently represent O or S.

In formula (A1-2), ma21 is 0 or 1, and ma22 is 0 or 1.

In formula (A1-2), the total number of O and/or S contained in the alkylene group as R ^a202 and the number of O and/or S contained in the alkylene group as R ^a204 is preferably 2 or more.
When the compound (A1-2) contains O and/or S in a specific amount or more in a specific portion, excessive loss in weight of components other than the solvent when the composition is heated can be suppressed, and dispersion of the inorganic fine particles (B) in the composition can be easily stabilized.
There is no particular upper limit on the total number of O and/or S groups contained in the alkylene group represented by R ^a202 and the total number of O and/or S groups contained in the alkylene group represented by R ^a204 , as long as the desired effect is not impaired.
The total number of O and/or S contained in the alkylene group represented by R ^a202 and the number of O and/or S contained in the alkylene group represented by R ^a204 is, for example, preferably 2 or more and 10 or less, more preferably 2 or more and 8 or less, and even more preferably 2 or more and 6 or less.

Preferable specific examples of the compound (A1-2) include the following compounds.
In the following compounds, the linking group linking an acryloyloxy group or a methacryloyloxy group with an aryloxy group, an arylthio group, a heteroaryloxy group or a heteroarylthio group is -CH ₂ CH ₂ -O-CH ₂ CH ₂ -, -(CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₂ -, -(CH ₂ CH ₂ -O) ₃ -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH ₂ CH ₂ -,
Compounds in which the substituent is changed to --(CH ₂ CH ₂ --S) ₂ --CH ₂ CH ₂ -- or --(CH ₂ CH ₂ --S) ₃ --CH ₂ CH ₂ -- are also preferred as compound (A1-2).

[Compound (A1-3)]
R ^a301 -R ^a302 -X ^a301 -Ph ³¹ -CO-O-R ^a303 ... (A1-3)
(In formula (A1-3), R ^a301 is a radically polymerizable group-containing group or a cationically polymerizable group-containing group, X ^a301 is O or S, R ^a302 is a single bond or a divalent linking group, R ^a303 is a benzyl group or a phenethyl group, and Ph ³¹ is a phenylene group.)

In formula (A1-3), Ph ³¹ is a phenylene group. The phenylene group represented by Ph ³¹ may be any one of an o-phenylene group, an m-phenylene group, and a p-phenylene group, and is preferably a p-phenylene group.

R ^a301 is a radical polymerizable group-containing group or a cationic polymerizable group-containing group. The radical polymerizable group and the cationic polymerizable group are as described above. As the radical polymerizable group as R ^a301 , a (meth)acryloyl group-containing group is preferable, and a (meth)acryloyl group is more preferable. As the cationic polymerizable group as R ^a301 , a vinyl group, a vinyloxy group-containing group, and an epoxy group-containing group are preferable, a vinyl group and an epoxy group-containing group are more preferable, and an alicyclic epoxy group-containing group and a glycidyl group are preferable.
A vinyl group is generally a radically polymerizable group, but in formula (A1-3), when R ^a301 is a vinyl group and R ^a302 is a single bond, the vinyl group forms a cationically polymerizable group, that is, a vinyloxy group or a vinylthio group, together with X ^a301 which is O or S. For this reason, in formula (A1-3), when R ^a302 is a single bond, the vinyl group as R ^a301 is a cationically polymerizable group rather than a radically polymerizable group.

R ^a302 is a single bond or a divalent linking group. The structure of the divalent linking group is not particularly limited as long as the desired effect is not impaired. It is preferable that the divalent linking group does not contain an aromatic group.
The divalent linking group represented by R ^a302 is a group represented by the following formula (A1-3-1):
-X ^a302 -R ^a304 - ... (A1-3-1)
(In formula (A1-3-1), R ^a304 is an alkylene group which may be interrupted by one or more O and/or S, and X ^a302 is O or S.)
A group represented by the following formula is preferred.
In addition, R ^a304 in the divalent group represented by formula (A1-3-1) is bonded to X ^a301 .
In formula (A1-3-1), R ^a304 is preferably an alkylene group interrupted by one or more O and/or S, and more preferably an alkylene group interrupted by one or more O, because the desired effects can be easily obtained by using compound (A1-3).
Since the desired effects can be easily obtained by using compound (A1-3), when R ^a304 is an alkylene group interrupted by one or more O and/or S, the total number of O and S contained in the alkylene group interrupted by one or more O and/or S is preferably 1 or more and 10 or less, more preferably 1 or more and 8 or less, even more preferably 1 or more and 6 or less, still more preferably 1 or more and 4 or less, and particularly preferably 1 or more and 3 or less.
The number of carbon atoms of the alkylene group which may be interrupted by one or more O and/or S as R ^a304 is not particularly limited as long as the desired effect is not impaired.

The alkylene group which may be interrupted by one or more O and/or S as R ^a304 is preferably a group consisting of ma aliphatic chain saturated hydrocarbon groups selected from an alkylene group having from 1 to 4 carbon atoms, an alkanetriyl group having from 1 to 4 carbon atoms, and an alkyl group having from 1 to 4 carbon atoms, and (ma-1) O and/or S linking the ma aliphatic chain saturated hydrocarbon groups.
Here, ma is an integer between 2 and 6.

Suitable examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, and a butane-1,4-diyl group. Of these groups, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, and a propane-1,3-diyl group are preferred.
Preferred examples of the alkanetriyl group having 1 to 4 carbon atoms include a propane-1,2,3-triyl group, a butane-1,2,3-triyl group, and a butane-1,2,4-triyl group. Of these groups, a propane-1,2,3-triyl group is preferred.
Preferred examples of the alkyl group having 1 to 4 carbon atoms 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, and a tert-butyl group. Among these groups, a methyl group and an ethyl group are preferred.

The alkylene group which may be interrupted by one or more O and/or S as R ^a304 is preferably a group consisting of ma alkylene groups having 1 to 4 carbon atoms and (ma-1) O and/or S linking the ma alkylene groups.
Here, ma is an integer between 2 and 6.

Preferable specific examples of the alkylene group which may be interrupted by one or more O and/or S, as R ^a304 , include the following groups.
-CH2CH2 _{- O - CH2CH2-}
-( _{CH2CH2 -} O) _{2 - CH2CH2-}
-( _{CH2CH2 -} O) _{3 - CH2CH2-}
-( _{CH2CH2 -} O) _{4 - CH2CH2-}
-( _{CH2CH2 -} O) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -O-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -O) ₅ -C( _CH3 ) _{HCH2-
--CH2CH2CH2 - O - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - O} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - O} ) _{5 - CH2CH2CH2-}
-CH2C( _{OCH3 ) HCH2-
-CH2C} ( _{OCH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH3 ) HCH2-
-CH2C ( OCH2CH2CH2CH3 ) HCH2- ​}
-CH2CH2 _{- S - CH2CH2-}
-( _{CH2CH2 -} S) _{2 - CH2CH2-}
-( _{CH2CH2 -} S) _{3 - CH2CH2-}
-( _{CH2CH2 -} S) _{4 - CH2CH2-}
-( _{CH2CH2 -} S) _{5 - CH2CH2-}
-C( _CH3 ) _HCH2 -S-C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₂ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₃ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₄ -C( _CH3 ) _HCH2-
-(C( _CH3 ) _HCH2 -S) ₅ -C( _CH3 ) _{HCH2-
-CH2CH2CH2 - S - CH2CH2CH2- ​
-} ( _{CH2CH2CH2 - S} ) _{2 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{3 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{4 - CH2CH2CH2-
-} ( _{CH2CH2CH2 - S} ) _{5 - CH2CH2CH2-}
-CH2C( _{SCH3 ) HCH2-
-CH2C} ( _{SCH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH3 ) HCH2-
-CH2C ( SCH2CH2CH2CH3 ) HCH2- ​}

Among these groups,
-CH2CH2 _{- O - CH2CH2-} ,
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,
-CH2CH2CH2 - O - CH2CH2CH2- ,}
-CH2CH2 _{- S - CH2CH2-} ,
-( _{CH2CH2 -} S) _{2 -CH2CH2- and} -( _{CH2CH2 -} S) _{3 -CH2CH2- are} preferred,
-( _{CH2CH2 -O} ) _{2 - CH2CH2-} ,
-( _{CH2CH2 -} O) _{3 -CH2CH2- ,}
--(CH ₂ CH ₂ --S) ₂ --CH ₂ CH ₂ -- and --(CH ₂ CH ₂ --S) ₃ --CH ₂ CH ₂ -- are more preferred.

Preferable specific examples of the compound (A1-3) include the following compounds.
In the following compounds, the linking group linking an acryloyloxy group or a methacryloyloxy group to a phenoxy group substituted with a benzyloxycarbonyl group, a phenoxy group substituted with a phenethyloxycarbonyl group, or a phenylthio group substituted with a benzyloxycarbonyl group is -CH ₂ CH ₂ -O-CH ₂ CH ₂ -, -(CH ₂ CH ₂ -O) ₂ -CH 2 CH 2 -, -(CH ₂ CH ₂ -O) ₃ -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ -S-CH _{2 CH 2} -, -(CH ₂ CH ₂ -S) ₂ -CH ₂ CH ₂ -, or -(CH ₂ CH _{2 -S} ) ₃ The compound in which --CH ₂ CH ₂ -- is changed is also preferred as the compound (A1-3).

[Compound (A1-4)]
(R ^a401 -X ^a401 -R ^a402 ) _ma41 -Ar ^a401 -C(=O)-Ar ^a402 -(R ^a403 -X ^a402 -R ^a404 ) _ma42 ... (A1-4)
In formula (A1-4), Ar ^a401 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma41+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; Ar ^a402 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma42+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a401 and R ^a404 are each independently a radical polymerizable group-containing group or a cation polymerizable group-containing group; X ^a401 and X ^a402 are each independently O or S; R ^a402 and R Each ^a403 is independently an alkylene group, ma41 is an integer of 1 or more and 3 or less, and ma42 is an integer of 0 or more and 3 or less.

In formula (A1-4), Ar ^a401 is a (ma41+1)-valent aromatic group having 6 to 12 carbon atoms and which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom. Ar ^a402 is a (ma42+1)-valent aromatic group having 6 to 12 carbon atoms and which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom.
The aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group.
Examples of the aromatic group include groups obtained by removing (ma41+1) or (ma42+1) hydrogen atoms from aromatic hydrocarbons such as benzene, naphthalene, and biphenyl, and groups obtained by removing (ma41+1) or (ma42+1) hydrogen atoms from aromatic heterocyclic compounds such as quinoline, isoquinoline, quinoxaline, cinnoline, quinazoline, phthalazine, naphthyridine, benzoxazole, benzothiazole, benzimidazole, indole, benzofuran, benzothiophene, isoindole, and isobenzofuran.

The aromatic groups represented by Ar ^a401 and Ar ^a402 may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 5 carbon atoms, a cyano group, and a halogen atom.
The number of substituents bonded to the aromatic groups represented by Ar ^a401 and Ar ^a402 is not particularly limited.
Examples of the alkyl group having 1 to 5 carbon atoms 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 neopentyl group, a sec-pentyl group, and a tert-pentyl group. Of these groups, a methyl group and an ethyl group are preferred.
Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.
The aromatic groups represented by Ar ^a401 and Ar ^a402 described above are preferably groups in which (ma41+1) or (ma42+1) hydrogen atoms have been removed from benzene or naphthalene, and more preferably groups in which (ma41+1) or (ma42+1) hydrogen atoms have been removed from benzene.

R ^a401 and R ^a404 are each independently a radical polymerizable group-containing group or a cationic polymerizable group-containing group. The radical polymerizable group and the cationic polymerizable group are as described above. The radical polymerizable group-containing group of R ^a401 and R ^a404 is preferably a (meth)acryloyl group-containing group, more preferably a (meth)acryloyl group. The cationic polymerizable group-containing group of R ^a401 and R ^a404 is preferably a vinyl group, a vinyloxy group-containing group, and an epoxy group-containing group, more preferably a vinyl group and an epoxy group-containing group, and is preferably an alicyclic epoxy group-containing group and a glycidyl group.
A vinyl group is generally a radically polymerizable group, but in formula (A1-4), when R ^a401 and R ^a404 are vinyl groups, the vinyl groups form cationically polymerizable groups, that is, vinyloxy groups or vinylthio groups, together with X ^a401 and X ^a402 which are O or S. For this reason, in formula (A1-4), the vinyl groups as R ^a401 and R ^a404 are cationically polymerizable groups, not radically polymerizable groups.

R ^a402 and R ^a403 each independently represents an alkylene group.
The alkylene group may be linear or branched.
The alkylene group has preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, and further preferably 1 or more and 5 or less, in number of carbon atoms.
Suitable examples of the alkylene group include methylene, ethane-1,2-diyl, ethane-1,1-diyl, propane-1,3-diyl, propane-1,2-diyl, propane-1,1-diyl, propane-2,2-diyl, n-butane-1,4-diyl, n-pentane-1,5-diyl, n-hexane-1,6-diyl, n-heptane-1,7-diyl, n-octane-1,8-diyl, n-nonane-1,9-diyl, and n-decane-1,10-diyl. Of these, methylene, ethane-1,2-diyl, and propane-1,3-diyl are preferred.

In formula (A1-4), X ^a401 and X ^a402 each independently represent O or S.

In formula (A1-4), ma41 is an integer of 1 or more and 3 or less, and ma42 is an integer of 0 or more and 3 or less.
Since the desired effect can be easily obtained by using the compound (A1-4), ma41 is preferably 1 or 2, and ma42 is preferably 0 or 1.

Preferable specific examples of the compound (A1-4) include the following compounds.

Other examples of aromatic ring-containing polymerizable compounds (A1) include 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-(meth)acryloyloxy-2-hydroxypropyl phthalate, half (meth)acrylates of phthalic acid derivatives, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxypolyethoxyphenyl)propane, phthalic acid diglycidyl ester di(meth)acrylate, etc. These monofunctional compounds can be used alone or in combination of two or more.

The ratio of the mass of the aromatic ring-containing polymerizable compound (A1) to the mass of the photopolymerizable compound (A) is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, even more preferably 30% by mass or more and 70% by mass or less, and particularly preferably 40% by mass or more and 60% by mass or less.

[Polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure]
As described above, the photosensitive composition contains the aromatic ring-containing polymerizable compound (A1) and the polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure.

The dendrimer structure means a structure in which a branched structure is further branched to form multiple branched structures, and the branched structures spread out radially.
The hyperbranch structure means a structure in which the multiple branched structures extend in a branched manner in a predetermined direction or in two or more directions, rather than in a radial manner.

When the aromatic ring-containing polymerizable compound (A1) has a radical polymerizable group-containing group, the polymerizable compound (A2) also has a radical polymerizable group-containing group. When the aromatic ring-containing polymerizable compound (A1) has a cationic polymerizable group-containing group, the polymerizable compound (A2) also has a cationic polymerizable group-containing group.

The polymerizable compound (A2) is preferably a (meth)acrylate compound having a hyperbranched structure or a dendrimer structure, since the effects of the present invention can be more easily obtained.

The polymerizable compound (A2) is a polyfunctional polymerizable compound having polymerizable groups at a plurality of ends of a multi-branched structure.
From the viewpoint of curability, the number of polymerizable groups is preferably at least 4, more preferably at least 6. From the viewpoint of cure shrinkage, the number of polymerizable groups is preferably at most 18, more preferably at most 16.

The polymerizable compound (A2) may be one produced by a known production method, or a commercially available one. Examples of the production method of the polymerizable compound (A2) include the method described in JP-A-2016-190998.

Examples of the polymerizable compound (A2) having a dendrimer structure include Viscoat (registered trademark) #1000, SIRIUS-501, and SUBARU-501 manufactured by Osaka Organic Chemical Industry Ltd.
Examples of the polymerizable compound (A2) having a hyperbranched structure include CN2302, CN2303, and CN2304 manufactured by Arkema.

The polymerizable compound (A2) has a mass average molecular weight (Mw) of preferably 5000 or less, more preferably 3000 or less. The mass average molecular weight (Mw) is preferably 500 or more, more preferably 1000 or more.
The weight average molecular weight (Mw) is a value calculated in terms of standard polystyrene, measured by gel permeation chromatography (GPC).

The viscosity of the polymerizable compound (A2) at 20° C. (hereinafter also referred to as “viscosity (20° C.)”) is preferably 10,000 mPa·s or less, more preferably 7,000 mPa·s or less, and even more preferably 4,000 mPa·s or less. The viscosity of the polymerizable compound (A2) at 20° C. is preferably 10 mPa·s or more, more preferably 20 mPa·s or more, and even more preferably 40 mPa·s or more.
The viscosity (20° C.) of the polymerizable compound (A2) is a value measured by an E-type viscometer.

The ratio of the mass of the polymerizable compound (A2) to the mass of the photopolymerizable compound (A) is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, even more preferably 30% by mass or more and 70% by mass or less, and particularly preferably 40% by mass or more and 60% by mass or less.

[Other photopolymerizable compounds (A3)]
The photopolymerizable compound (A) may contain other photopolymerizable compounds (A3) in addition to the aromatic ring-containing polymerizable compound (A1) and the polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure described above, as long as the desired effect is not impaired. When the aromatic ring-containing polymerizable compound (A1) has a radical polymerizable group-containing group, the compound (A3) also has a radical polymerizable group-containing group. When the aromatic ring-containing polymerizable compound (A1) has a cationic polymerizable group-containing group, the compound (A3) also has a cationic polymerizable group-containing group.

When the other photopolymerizable compound (A3) has a radically polymerizable group-containing group, the other photopolymerizable compound (A3) may be a monofunctional compound having one radically polymerizable group or a polyfunctional compound having two or more radically polymerizable groups, and a polyfunctional compound is preferred.
As the other photopolymerizable compound (A3) having a radical polymerizable group-containing group, a compound having one or more (meth)acryloyl groups, such as a (meth)acrylate compound or a (meth)acrylamide compound, is preferable, and a (meth)acrylate compound having one or more (meth)acryloyl groups is more preferable.

Examples of monofunctional compounds having a radical polymerizable group-containing group 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, and tert-butylacrylamide. Examples of such compounds include sulfonic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerin mono(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylamino (meth)acrylate, glycidyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, and 2,2,3,3-tetrafluoropropyl (meth)acrylate. These monofunctional compounds can be used alone or in combination of two or more.

Examples of polyfunctional compounds having radical polymerizable groups 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, dimethylol tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate. Examples of suitable polyfunctional compounds include polyvinyl alcohol, ...

Among these other photopolymerizable compounds (A3) having a radical polymerizable 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 strength of the material formed using the composition.

（ＭＡ－（Ｏ－Ｒ^ａ１）_ｎａ１－Ｘ－ＣＨ_２）_２－ＣＨ－Ｘ－（Ｒ^ａ１－Ｏ）_ｎａ１－ＭＡ・・・（Ａ－２ｂ）
（式（Ａ－２ａ）、及び式（Ａ－２ｂ）中、ＭＡは、それぞれ独立に、（メタ）アクリロイル基であり、Ｘは、それぞれ独立に、酸素原子、－ＮＨ－、又は－Ｎ（ＣＨ_３）－であり、Ｒ^ａ１は、それぞれ独立に、エタン－１，２－ジイル基、プロパン－１，２－ジイル基、又はプロパン－１，３－ジイル基であり、Ｒ^ａ２は、水酸基、炭素原子数１以上４以下のアルキル基、又は－Ｘ－（Ｒ^ａ１－Ｏ）_ｎａ１－ＭＡで表される基であり（Ｘは前記と同様であり）、ｎａ１、及びｎａ２は、それぞれ独立に、０又は１である。） The composition contains inorganic fine particles (B) described later. Depending on the composition of the composition, localization of the inorganic fine particles (B) may occur in a film formed using the composition, such that a layer rich in the inorganic fine particles (B) and a layer poor in the inorganic particles (B) are formed.
From the viewpoint of suppressing such localization, the composition preferably contains a compound represented by the following formula (A-2a) or the following formula (A-2b) as the other photopolymerizable compound (A3) having a radical polymerizable group-containing group:

(MA-(O-R ^a1 ) _na1 -X-CH ₂ ) ₂ -CH-X-(R ^a1 -O) _na1 -MA... (A-2b)
(In formula (A-2a) and formula (A-2b), each MA is independently a (meth)acryloyl group; each X is independently an oxygen atom, -NH-, or -N(CH ₃ )-; each R ^a1 is independently an ethane-1,2-diyl group, a propane-1,2-diyl group, or a propane-1,3-diyl group; R ^a2 is a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, or a group represented by -X-(R ^a1 -O) _na1 -MA (X is the same as above); and each na1 and na2 is independently 0 or 1.)

In formula (A-2a), examples of the alkyl group having 1 to 4 carbon atoms as R ^a2 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, and a tert-butyl group. Of these alkyl groups, a methyl group and an ethyl group are preferred.

Preferred examples of the compound represented by formula (A-2a) and the compound represented by formula (A-2b) include pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, and the following compounds 1) to 32), in which MA is a (meth)acryloyl group.
1) (MA-NH- _CH2 ) ₄ -C
2) (MA-N( _CH3 ) _-CH2 ) ₄ -C
3) (MA-O- _{CH2CH2CH2 -} O- _CH2 ) ₄ - _C
4) (MA-O- _{CH2CH2 -} O- _CH2 ) ₄ -C
5) (MA-O- _{CH2CH2CH2 - NH} - _CH2 ) ₄ -C
6) (MA-O- _CH2CH2 - _NH - _CH2 ) ₄ -C
7) (MA-O- _{CH2CH2CH2 - N} ( _CH3 ) _-CH2 ) ₄ -C
8) (MA-O- _{CH2CH2 -} N( _CH3 ) _-CH2 ) ₄ -C
9) (MA-NH- _CH2 ) ₃ -C- _CH2 -O-CH2 _- C-( _CH2 -NH-MA) ₃
10) (MA-N( _CH3 ) _-CH2 ) ₃ -C- _CH2- O-CH2 _- C-( _CH2 -N( _CH3 )-MA) ₃
11) (MA-O- _CH2CH2CH2 -O- _CH2 ) _{3 -} C- _{CH2 - O} -CH2 _- C-( _CH2 - _O - _CH2CH2CH2 -O-MA) ₃
12) (MA-O- _CH2CH2 -O- _CH2 ) ₃ -C- _{CH2 -} O-CH2 _- C-( _CH2 -O- _CH2CH2 - _O -MA) ₃
13) (MA-O- _CH2CH2CH2 -NH- _CH2 ) _{3 -} C- _{CH2 -} O- _CH2- C-( _CH2 -NH _{- CH2CH2CH2} - _O -MA) ₃
14) (MA-O- _CH2CH2 -NH- _CH2 ) ₃ -C- _{CH2 -} O- _{CH2- C-} ( _CH2 -NH- _CH2CH2 -O-MA) ₃
15) (MA-O- _{CH2CH2CH2 - N} ( _CH3 ) _-CH2 ) ₃ -C- _CH2 - _O - _CH2- C-( _{CH2 -} N(CH3 _{) -CH2CH2CH2} -O-MA) ₃
16) (MA-O- _{CH2CH2 -} N( _CH3 ) _-CH2 ) _{3 -} C- _CH2 -O- _CH2- C-(CH2 _- N( _CH3 ) _-CH2CH2 -O-MA) ₃
17) (MA-NH- _CH2 ) ₂ -CH-NH-MA
18) (MA-N( _CH3 ) _-CH2 ) _2- CH-N( _CH3 )-MA
19) (MA-O- _CH2CH2CH2 - _O - _CH2 ) _{2 - CH -} O- _CH2CH2CH2 -O-MA
20) (MA-O- _CH2CH2 - _O - _CH2 ) ₂ -CH-C-O- _CH2CH2 - _O -MA
21) (MA-O _{- CH2CH2CH2} -NH- _CH2 ) _{2 - CH} -NH _{- CH2CH2CH2} -O-MA
22) (MA-O- _CH2CH2 - _NH - _CH2 ) ₂ - _CH2 -NH _- CH2CH2- _O -MA
23) (MA-O-CH2CH2CH2 _{- N} ( _{CH3 ) -CH2} ) ₂ - _{CH2 -} N( _{CH3 ) -CH2CH2CH2} -O-MA
24) (MA-O- _{CH2CH2 -} N( _CH3 ) _-CH2 ) _{2 - CH2} -N( _CH3 )-CH2CH2- _O -MA
25) (MA-NH- _CH2 ) ₃ -C _{- CH2CH3}
26) (MA-N( _CH3 ) _-CH2 ) ₃ -C _{- CH2CH3}
27) (MA-O- _{CH2CH2CH2 - O} - _CH2 ) ₃ -C _{- CH2CH3}
28) (MA-O- _{CH2CH2 -} O- _CH2 ) ₃ -C _{- CH2CH3}
29) (MA-O- _{CH2CH2CH2 - NH} - _CH2 ) ₃ -C _{- CH2CH3}
30) (MA-O- _CH2CH2 - _NH - _CH2 ) ₃ -C _{- CH2CH3}
31) (MA-O- _{CH2CH2CH2 - N} ( _CH3 ) _-CH2 ) ₃ - _C - _CH2CH3
32) (MA-O- _{CH2CH2 -} N( _CH3 ) _-CH2 ) ₃ -C _{- CH2CH3}

The content of the photopolymerizable compound (A) in the composition is not particularly limited as long as the desired effect is not inhibited. The content of the photopolymerizable compound (A) in the composition is preferably 0.1 parts by mass or more and 50 parts by mass or less, more preferably 0.5 parts by mass or more and 40 parts by mass or less, and particularly preferably 1 part by mass or more and 25 parts by mass or less, when the mass of the composition excluding the mass of the solvent (S) described below is taken as 100 parts by mass.

<Inorganic fine particles (B)>
The composition contains inorganic fine particles (B). The material of the inorganic fine particles (B) is not particularly limited as long as it is an inorganic material. The inorganic fine particles (B) are preferably one or more selected from the group consisting of metal oxide fine particles (B1) and metal fine particles (B2).
When the composition contains metal oxide fine particles (B1), it is easy to form a material with a high refractive index using the composition. When the composition contains metal fine particles (B2), the material formed using the composition is given electrical conductivity, or the light absorption of a specific wavelength of the material formed using the composition is enhanced. For this reason, the composition containing metal fine particles (B2) is used to form a material that can be applied to a bandpass filter.
The type of metal oxide constituting the metal oxide fine particles (B1) is not particularly limited as long as the desired effect is not impaired. Preferred examples of the metal oxide fine particles (B1) include at least one selected from the group consisting of zirconium oxide fine particles, titanium oxide fine particles, barium titanate fine particles, cerium oxide fine particles, and niobium oxide fine particles.
The type of metal constituting the metal fine particles (B2) is not particularly limited as long as the desired effect is not impaired. The metal constituting the metal fine particles (B2) may be a simple substance or an alloy. Preferred examples of the metal fine particles (B2) include gold fine particles and platinum fine particles. Other preferred examples of the inorganic fine particles (B) include silicon fine particles (SiNC (silicon nanoparticles)), which are semimetallic fine particles.
Among the specific examples of the inorganic fine particles explained above, at least one selected from the group consisting of titanium oxide fine particles, zirconium oxide fine particles, and niobium oxide fine particles, which are metal oxide fine particles (B1), is particularly preferred.
The composition may contain one type of these inorganic fine particles (B) alone or two or more types in combination.

The average particle size of the inorganic fine particles (B) is preferably 500 nm or less, and more preferably 2 nm or more and 100 nm or less, from the viewpoints of the transparency of the material formed using the composition and the dispersion stability of the inorganic fine particles (B) in the composition.

The metal oxide fine particles (B1) are preferably those whose surfaces are modified with an ethylenically unsaturated double bond-containing group.
When the surface of the metal oxide fine particles (B1) is modified with an ethylenically unsaturated double bond-containing group, aggregation of the metal oxide fine particles (B1) is less likely to occur. Therefore, when the surface of the metal oxide fine particles (B1) is modified with an ethylenically unsaturated double bond-containing group, localization of the metal oxide fine particles (B1) in a material formed using the composition is particularly easily suppressed.

For example, by applying a capping agent containing an ethylenically unsaturated double bond to the surface of metal oxide fine particles (B1), metal oxide fine particles (B1) whose surface is modified with an ethylenically unsaturated double bond-containing group via a chemical bond such as a covalent bond can be obtained.

There is no particular limitation on the method for bonding the capping agent containing an ethylenically unsaturated double bond to the surface of the metal oxide fine particles (B1) via a chemical bond such as a covalent bond. Hydroxyl groups are usually present on the surface of the metal oxide fine particles (B1). The capping agent is covalently bonded to the surface of the metal oxide fine particles (B1) by reacting the hydroxyl groups with reactive groups of the capping agent.
Preferred examples of the reactive group possessed by the capping agent include trialkoxysilyl groups such as trimethoxysilyl group and triethoxyl group; dialkoxysilyl groups such as dimethoxysilyl group and diethoxysilyl group; monoalkoxysilyl groups such as monomethoxysilyl group and monoethoxysilyl group; trihalosilyl groups such as trichlorosilyl group; dihalosilyl groups such as dichlorosilyl group; monohalosilyl groups such as monochlorosilyl group; carboxy group; halocarbonyl groups such as chlorocarbonyl group; hydroxyl group; phosphono group (-P(=O)(OH) ₂ ); and phosphate group (-O-P(=O)(OH) ₂ ).

The trialkoxysilyl group, the dialkoxysilyl group, the monoalkoxysilyl group, the trihalosilyl group, the dihalosilyl group, and the monohalosilyl group form a siloxane bond with the surface of the metal oxide nanoparticles (B).
The carboxy group and the halocarbonyl group form a bond represented by (metal oxide --O--CO--) with the surface of the metal oxide fine particles (B1).
The hydroxyl group forms a bond represented by (metal oxide-O-) with the surface of the metal oxide fine particles (B).
The phosphono group and the phosphate group form a bond represented by (metal oxide-O--P(=O)<) with the surface of the metal oxide fine particles (B1).

In the capping agent, the group that bonds to the reactive group may be a hydrogen atom or various organic groups, which may contain heteroatoms such as O, N, S, P, B, Si, or halogen atoms.
Examples of the group that bonds to the reactive group include an alkyl group which may be linear or branched and may be interrupted by an oxygen atom (-O-), an alkenyl group which may be linear or branched and may be interrupted by an oxygen atom (-O-), an alkynyl group which may be linear or branched and may be interrupted by an oxygen atom (-O-), a cycloalkyl group, an aromatic hydrocarbon group, and a heterocyclic group.
These groups may be substituted with a substituent such as a halogen atom, an epoxy group-containing group such as a glycidyl group, a hydroxyl group, a mercapto group, an amino group, a (meth)acryloyl group, an isocyanate group, etc. The number of the substituents is not particularly limited.

Furthermore, as the group bonded to the above reactive group, a group represented by -(SiR ^b1 R ^b2 -O-) _r -(SiR ^b3 R ^b4 -O-) _s -R ^b5 is also preferred. ^{R b1} , R ^b2 , R ^b3 and ^Rb4 are each an organic group which may be the same or different. Suitable examples of the organic group include alkyl groups such as a methyl group and an ethyl group; alkenyl groups such as a vinyl group and an allyl group; aromatic hydrocarbon groups such as a phenyl group, a naphthyl group and a tolyl group; epoxy group-containing groups such as a 3-glycidoxypropyl group; and a (meth)acryloyloxy group.
In the above formula, examples of R ^b5 include terminal groups such as -Si(CH ₃ ) ₃ , -Si(CH ₃ ) ₂ H, -Si(CH ₃ ) ₂ (CH=CH ₂ ), and -Si(CH ₃ ) ₂ (CH ₂ CH ₂ CH ₂ CH ₃ ).
In the above formula, r and s are each independently an integer of 0 to 60. In the above formula, r and s cannot both be 0.

Specific examples of suitable capping agents include unsaturated group-containing alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 1-hexenyltrimethoxysilane, 1-hexenyltriethoxysilane, 1-octenyltrimethoxysilane, 1-octenyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloylpropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-methacryloyloxypropyltriethoxysilane; unsaturated group-containing alcohols such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, allyl alcohol, ethylene glycol monoallyl ether, propylene glycol monoallyl ether, and 3-allyloxypropanol; (meth)acrylic acid; and (meth)acrylic acid halides such as (meth)acrylic acid chloride.

The amount of capping agent used when bonding the capping agent to the surface of the metal oxide fine particles (B1) via a chemical bond such as a covalent bond is not particularly limited. Preferably, a sufficient amount of capping agent is used to react with almost all of the hydroxyl groups on the surface of the metal oxide fine particles (B1).

The content of the inorganic fine particles (B) in the composition is not particularly limited as long as it does not impair the object of the present invention. The content of the inorganic fine particles (B) in the composition is preferably 5% by mass or more and 95% by mass or less, more preferably 35% by mass or more and 93% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less, based on the mass of the composition excluding the mass of the solvent (S).
When the content of the inorganic fine particles (B) in the composition is within the above range, it is easy to obtain a composition in which the inorganic fine particles (B) are stably dispersed, and it is also easy to form a material having the desired effects brought about by the use of the inorganic fine particles (B) using the composition.
When the inorganic fine particles (B) are metal oxide fine particles (B1), from the viewpoint of facilitating the formation of a material having a high refractive index, the content of the metal oxide fine particles (B1) in the composition is preferably 90 mass% or more, more preferably 90 mass% or more and 98 mass% or less, and even more preferably 90 mass% or more and 95 mass% or less, relative to the mass of the composition excluding the mass of the solvent (S).
In addition, when the surface of the metal oxide fine particles (B1) is modified with an ethylenically unsaturated double bond-containing group, the mass of the capping agent having an ethylenically unsaturated double bond-containing group present on the surface of the metal oxide fine particles (B1) is included in the mass of the metal oxide fine particles (B1).

[Plasticizer (D)]
The composition may contain a plasticizer (D). The plasticizer (D) is a component that reduces the viscosity of the composition without significantly impairing the physical properties, such as the high refractive index, of a material formed using the composition.

The plasticizer (D) is preferably a compound represented by the following formula (d-1):
R ^d1 -R ^d3 _r -X ^d -R ^d4 _s -R ^d2 ... (d-1)
(In formula (d-1), R ^d1 and R ^d2 each independently represent a phenyl group which may have 1 to 5 substituents, and the substituents are selected from an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom; R ^d3 and R ^d4 each independently represent a methylene group or an ethane-1,2-diyl group; r and s each independently represent 0 or 1; and X ^d represents an oxygen atom or a sulfur atom.)

By including such a plasticizer (D) in the composition, the viscosity of the composition can be reduced without significantly impairing the physical properties, such as the high refractive index, of a material formed using the composition.
From the viewpoint of reducing the viscosity of the composition, the viscosity of the plasticizer (D) measured at 25° C. with an E-type viscometer is preferably 10 cP or less, more preferably 8 cP or less, and even more preferably 6 cP or less.
In addition, in order to prevent the plasticizer (D) from volatilizing easily and to easily maintain the effect of reducing the viscosity of the composition, the boiling point of the plasticizer (D) under atmospheric pressure is preferably 250° C. or higher, and more preferably 260° C. or higher. The upper limit of the boiling point of the plasticizer (D) under atmospheric pressure is not particularly limited, but may be, for example, 300° C. or lower, or 350° C. or lower.

R ^d1 and R ^d2 in formula (d-1) are each independently a phenyl group which may have 1 to 5 substituents. The substituent bonded to the phenyl group is a group selected from an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. When the phenyl group has a substituent, the number of the substituents is not particularly limited. The number of the substituents is 1 to 5, preferably 1 or 2, and more preferably 1. From the viewpoint of reducing the viscosity of the composition, it is preferable that R ^d1 and R ^d2 are each an unsubstituted phenyl group.

Examples of the alkyl group having 1 to 4 carbon atoms as a substituent 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, and a tert-butyl group. Examples of the alkoxy group having 1 to 4 carbon atoms as a substituent 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, and a tert-butyloxy group. Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In formula (d-1), R ^d3 and R ^d4 each independently represent a methylene group or an ethane-1,2-diyl group.
In formula (d-1), ^Xd is an oxygen atom or a sulfur atom.

Specific preferred examples of the compound represented by formula (d-1) described above include diphenyl ether, diphenyl sulfide, dibenzyl ether, dibenzyl sulfide, diphenethyl ether, and diphenethyl sulfide. Among these, diphenyl sulfide and/or dibenzyl ether are more preferred.

The content of the plasticizer (D) in the composition is preferably more than 0% by mass and not more than 35% by mass, more preferably 5% by mass or more and not more than 15% by mass, in terms of achieving both viscosity adjustment and dispersibility of the inorganic fine particles (B) relative to the mass of the entire composition.

[Nitrogen-containing compound (E)]
For the purpose of easily suppressing localization of the inorganic fine particles (B) in a material formed using the composition, the composition may contain, as a nitrogen-containing compound (E), an amine compound (E1) represented by the following formula (e1) and/or an imine compound (E2) represented by the following formula (e2):
NR ^e1 R ^e2 R ^e3 ... (e1)
In formula (e1), R ^e1 , R ^e2 , and R ^e3 each independently represent a hydrogen atom or an organic group.
R ^e4 −N═CR ^e5 R ^e6 . . . (e2)
(In formula (e2), R ^e4 , R ^e5 , and R ^de6 each independently represent a hydrogen atom or an organic group.)

In formula (e1) and formula (e2), when R ^e1 , R ^e2 , R ^e3 , R ^e4 , R ^e5 , and R ^de6 are organic groups, the organic groups can be selected from various organic groups within the scope of not impairing the desired effect. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms of the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
Suitable examples of the organic group include an alkyl group, a cycloalkyl group, a phenyl group which may have a substituent, a phenylalkyl group which may have a substituent, a naphthyl group which may have a substituent, a naphthylalkyl group which may have a substituent, and a heterocyclyl group which may have a substituent.

The number of carbon atoms of the alkyl group as an organic group is preferably 1 to 20, more preferably 1 to 6. The structure of the alkyl group may be linear or branched. Specific examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, sec-octyl, tert-octyl, n-nonyl, isononyl, n-decyl, and isodecyl. The alkyl group may also contain an ether bond (-O-) in the carbon chain. Examples of alkyl groups 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.

The number of carbon atoms in the cycloalkyl group as an organic group is preferably 3 to 10, more preferably 3 to 6. Specific examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups.

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

In the case where the organic group is a heterocyclyl group, the heterocyclyl group is the same as when R ^c4 in formula (c3) is a heterocyclyl group, and the heterocyclyl group may further have a substituent.

The heterocyclyl group as an organic group may be an aliphatic heterocyclic group or an aromatic heterocyclic group. The heterocyclyl group is preferably 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 condensed with each other, or such a monocyclic ring is condensed with a benzene ring. When the heterocyclyl group is a condensed ring, the number of rings is up to 3. Examples of heterocyclic rings 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.

When the phenyl group, naphthyl group, and heterocyclyl group contained in the above organic group have a substituent, examples of the substituent include an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a halogenated alkyl group having from 1 to 6 carbon atoms, a halogenated alkoxy group having from 1 to 6 carbon atoms, a saturated aliphatic acyl group having from 2 to 7 carbon atoms, an alkoxycarbonyl group having from 2 to 7 carbon atoms, a saturated aliphatic acyloxy group having from 2 to 7 carbon atoms, a monoalkylamino group having an alkyl group having from 1 to 6 carbon atoms, a dialkylamino group having an alkyl group having from 1 to 6 carbon atoms, a benzoyl group, a halogen atom, a nitro group, and a cyano group.
When the phenyl group, naphthyl group, and heterocyclyl group contained in the organic group have a substituent, the number of the substituents is not particularly limited, and is preferably from 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group contained in the organic group have a plurality of substituents, the plurality of substituents may be the same or different.

In formula (e1), R ^e1 , R ^e2 and R ^e3 each independently represent a hydrogen atom or an organic group, and at least one of R ^e1 , R ^e2 and R ^e3 is an aromatic group-containing group.
In addition, in formula (e2), R ^e4 , R ^e5 , and R ^de6 each independently represent a hydrogen atom or an organic group, and at least one of R ^e4 , R ^e5 , and R ^de6 is an aromatic group-containing group.
The aromatic ring in the aromatic group-containing group may be an aromatic hydrocarbon ring or an aromatic heterocycle. The aromatic group-containing group is preferably a hydrocarbon group. The aromatic group-containing group is preferably an aromatic hydrocarbon group (aryl group) or an aralkyl group.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthalene-1-yl group, and a naphthalene-2-yl group. Of these aromatic hydrocarbon groups, a phenyl group is preferred.
Aralkyl groups include benzyl, 2-phenylethyl, 3-phenylpropyl, and 4-phenylbutyl groups.

In formula (e1), at least one of R ^e1 , R ^e2 and R ^e3 is preferably a group represented by Ar ^e1 -CH ₂ -. In formula (d2), R ^e4 is preferably a group represented by Ar ^e1 -CH ₂ -. Ar ^e1 is an aromatic group which may have a substituent.
The aromatic group represented by Ar ^e1 may be an aromatic hydrocarbon group or an aromatic heterocyclic group. The aromatic group represented by Ar ^e1 is preferably an aromatic hydrocarbon group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthalene-1-yl group, and a naphthalene-2-yl group. Of these aromatic hydrocarbon groups, a phenyl group is preferred.
The substituents that the aromatic group represented by Ar ^e1 may have are the same as the substituents that the organic groups represented by R ^e1 , R ^e2 , R ^e3 , R ^e4 , R ^e5 , and R ^e6 may have when they are a phenyl group, a naphthyl group, or a heterocyclyl group.

Specific examples of suitable amine compounds represented by formula (e1) include triphenylamine, N,N-diphenylbenzylamine, N-phenyldibenzylamine, tribendialumine, N,N-dimethylphenylamine, N-methyldiphenylamine, N,N-dimethylbenzylamine, N-methyldibenzylamine, N-methyl-N-benzylphenylamine, N,N-diethylphenylamine, N-ethyldiphenylamine, N,N-diethylbenzylamine, N-ethyldibenzylamine, and N-ethyl-N-benzylphenylamine.

Specific examples of suitable imine compounds represented by formula (e2) include N-benzylphenylmethanimine, N-benzyldiphenylmethanimine, N-benzyl-1-phenylethanimine, and N-benzylpropan-2-imine.

The content of the nitrogen-containing compound (E) in the composition is not particularly limited as long as the desired effect is not impaired. The content of the nitrogen-containing compound (E) is preferably 5% by mass or more and 25% by mass or less, and more preferably 7% by mass or more and 20% by mass or less, relative to the mass of the photopolymerizable compound (A).

<Triazine Compound (F)>
For the purpose of increasing the refractive index of a material formed using the composition, the composition may contain a compound represented by the following formula (F1) as the triazine compound (F).

In formula (F1), R ^F1 , R ^F2 and R ^F3 each independently represent a monocyclic aromatic group which may have a substituent, or a fused aromatic group which may have a substituent.
However, R ^F1 , R ^F2 and R ^F3 do not contain a radically polymerizable group-containing group or a cationically polymerizable group-containing group.
When the monocyclic aromatic group or the fused aromatic group has a substituent, the substituent does not contain an aromatic ring.
The three --NH-- groups bonded to the triazine ring are bonded to aromatic rings in R ^F1 , R ^F2 , and R ^F3 , respectively.

The monocyclic aromatic group represented by R ^F1 , R ^F2 , and R ^F3 may be an aromatic hydrocarbon group or an aromatic heterocyclic group. Examples of the monocyclic aromatic group include a phenyl group, a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a furanyl group, a thienyl group, an oxazolyl group, and a thiazolyl group.

Examples of the substituent that the monocyclic aromatic group may have include a halogen atom, a hydroxyl group, a mercapto group, a cyano group, a nitro group, and a monovalent organic group, provided that the monovalent organic group does not contain an aromatic ring.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the monovalent organic group include an alkyl group, an alkoxy group, an alkoxyalkyl group, an aliphatic acyl group, an aliphatic acyloxy group, an alkoxycarbonyl group, an alkylthio group, and an aliphatic acylthio group.

The number of carbon atoms of the monovalent organic group as a substituent is not particularly limited as long as the desired effect is not impaired. The number of carbon atoms of the monovalent organic group as a substituent is, for example, preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 8. For alkoxyalkyl groups, aliphatic acyl groups, aliphatic acyloxy groups, alkoxycarbonyl groups, alkoxyalkylthio groups, and aliphatic acylthio groups, the lower limit of the number of carbon atoms is 2.

Specific examples of preferred alkyl groups as substituents include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups.

Specific preferred examples of alkoxy groups as substituents include methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, tert-butyloxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, and n-octyloxy.

Specific examples of preferred alkoxyalkyl groups as substituents include methoxymethyl, ethoxymethyl, n-propyloxymethyl, n-butyloxymethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-n-propyloxyethyl, 2-n-butyloxyethyl, 3-methoxy-n-propyloxy, 3-ethoxy-n-propyloxy, 3-n-propyloxy-n-propyloxy, 3-n-butyloxy-n-propyloxy, 4-methoxy-n-butyloxy, 4-ethoxy-n-butyloxy, 4-n-propyloxy-n-butyloxy, and 4-n-butyloxy-n-butyloxy.

Specific examples of preferred aliphatic acyl groups as substituents include acetyl, propionyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, and octanoyl groups.

Specific preferred examples of the aliphatic acyloxy group as a substituent include an acetoxy group, a propionyloxy group, a butanoyloxy group, a pentanoyloxy group, a hexanoyloxy group, a heptanoyloxy group, and an octanoyloxy group.

Specific preferred examples of alkoxycarbonyl groups as substituents include methoxycarbonyl groups, ethoxycarbonyl groups, n-propyloxycarbonyl groups, isopropyloxycarbonyl groups, n-butyloxycarbonyl groups, isobutyloxycarbonyl groups, sec-butyloxycarbonyl groups, tert-butyloxycarbonyl groups, n-pentyloxycarbonyl groups, n-hexyloxycarbonyl groups, n-heptyloxycarbonyl groups, and n-octyloxycarbonyl groups.

Specific preferred examples of alkylthio groups as substituents include methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, isobutylthio, sec-butylthio, tert-butylthio, n-pentylthio, n-hexylthio, n-heptylthio, and n-octylthio.

Specific preferred examples of the aliphatic acylthio group as a substituent include an acetylthio group, a propionylthio group, a butanoylthio group, a pentanoylthio group, a hexanoylthio group, a heptanoylthio group, and an octanoylthio group.

When the monocyclic aromatic group has a substituent, the number of the substituent is not particularly limited as long as the desired effect is not impaired. When the monocyclic aromatic group has a substituent, the number of the substituent is preferably 1 or more and 4 or less, more preferably 1 or 2, and particularly preferably 1.
When the monocyclic aromatic group has multiple substituents, the multiple substituents may be different from each other.

The monocyclic aromatic groups which may have a substituent as described above include a phenyl group, a 4-cyanophenyl group, a 3-cyanophenyl group, a 2-cyanophenyl group, a 2,3-dicyanophenyl group, a 2,4-dicyanophenyl group, a 2,5-dicyanophenyl group, a 2,6-dicyanophenyl group, a 3,4-dicyanophenyl group, a 3,5-dicyanophenyl group, a 4-nitrophenyl group, a 3-nitrophenyl group, a 2-nitrophenyl group, a 4-chlorophenyl group, a 3-chlorophenyl group, a 2-chlorophenyl group, a 4-bromophenyl group, a 3-bromophenyl group, a 2-bromophenyl group, a 4-iodophenyl group, a 3-iodophenyl group, a 2-iodophenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-methylphenyl group, a 3-methylphenyl group, and a 2-methylphenyl group.

Of these groups, phenyl, 4-cyanophenyl, 3-cyanophenyl, 2-cyanophenyl, 4-nitrophenyl, 3-nitrophenyl, and 2-nitrophenyl groups are preferred, with phenyl and 4-cyanophenyl groups being more preferred.

The condensed aromatic group as R ^F1 , R ^F2 and R ^F3 is a group that removes one hydrogen atom from a condensed polycycle that is condensed with two or more aromatic monocycles.The number of aromatic monocycles that constitute the condensed aromatic group is not particularly limited.The number of aromatic monocycles that constitute the condensed aromatic group is preferably 2 or 3, more preferably 2.In other words, the condensed aromatic group is preferably a bicyclic condensed aromatic group or a tricyclic condensed aromatic group, and more preferably a bicyclic condensed aromatic group.
The fused aromatic group may be an aromatic hydrocarbon group or an aromatic heterocyclic group.

Examples of bicyclic condensed aromatic groups include naphthalene-1-yl, naphthalene-2-yl, quinolin-2-yl, quinolin-3-yl, quinolin-4-yl, quinolin-5-yl, quinolin-6-yl, quinolin-7-yl, quinolin-8-yl, isoquinolin-1-yl, isoquinolin-3-yl, isoquinolin-4-yl, isoquinolin-5-yl, isoquinolin-6-yl, isoquinolin Examples of the quinolin-7-yl group, and the isoquinolin-8-yl group, the benzoxazol-2-yl group, the benzoxazol-4-yl group, the benzoxazol-5-yl group, the benzoxazol-6-yl group, the benzoxazol-7-yl group, the benzothiazol-2-yl group, the benzothiazol-4-yl group, the benzothiazol-5-yl group, the benzothiazol-6-yl group, and the benzothiazol-7-yl group.

Examples of tricyclic fused aromatic groups include anthracen-1-yl, anthracen-2-yl, anthracen-9-yl, phenanthren-1-yl, phenanthren-2-yl, phenanthren-3-yl, phenanthren-4-yl, phenanthren-9-yl, acridine-1-yl, acridine-2-yl, acridine-3-yl, acridine-4-yl, and acridine-9-yl.

The substituents that may be possessed by polycyclic fused aromatic groups, such as bicyclic fused aromatic groups and tricyclic fused aromatic groups, are the same as those that may be possessed by monocyclic aromatic groups.

As described above, the fused ring aromatic groups which may have a substituent are preferably naphthalene-1-yl, naphthalene-2-yl, quinolin-2-yl, quinolin-3-yl, quinolin-4-yl, quinolin-5-yl, quinolin-6-yl, quinolin-7-yl, quinolin-8-yl, benzothiazol-2-yl, and 2-mercaptobenzothiazol-6-yl.

Of these groups, naphthalene-1-yl, quinolin-3-yl, quinolin-4-yl, and 2-mercaptobenzothiazol-6-yl groups are preferred, with naphthalene-1-yl groups being more preferred.

Among the compounds represented by formula (F1) explained above, compounds in which one or two of R ^F1 , R ^F2 , and R F3 are naphthyl groups which may have a substituent, and one or two of R ^F1 , R ^F2 , and R ^F3 are 4-cyanophenyl groups or benzothiazolyl groups are preferred, because the refractive index, surface appearance, and heat ^resistance of the material formed using the composition are well balanced. As the naphthyl group which may have a substituent, a naphthalene-1-yl group is preferred.

Specific examples of suitable compounds represented by formula (F1) include compounds of the following formula:

The method for producing the compound represented by formula (F1) is not particularly limited. Typically, the compound can be produced by reacting a cyanuric halide such as cyanuric chloride with an aromatic amine represented by R ^F1 -NH ₂ , R ^F2 -NH ₂ , and R ^F3 -NH _2. These multiple amines may be reacted with the cyanuric halide simultaneously or sequentially, and it is preferable to react them with the cyanuric halide sequentially.

The compound represented by formula (F1) is usually synthesized in an organic solvent. Such an organic solvent is not particularly limited as long as it is an inert solvent that does not react with cyanuric halide, aromatic amine, radical polymerizable group, cationic polymerizable group, etc. As the solvent, the organic solvents exemplified as specific examples of the solvent (S) described later can be used.
In producing the compound represented by formula (F1), the temperature at which a cyanuric halide is reacted with an aromatic amine such as an aromatic amine represented by R ^F1 -NH ₂ , R ^F2 -NH ₂ , or R ^F3 -NH ₂ is reacted is not particularly limited. Typically, the reaction temperature is preferably 0° C. or higher and 150° C. or lower.

The content of the triazine compound (F) in the composition is not particularly limited as long as the desired effect is not inhibited. The content of the triazine compound (F) in the composition is, for example, preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.3 parts by mass or more and 20 parts by mass or less, and even more preferably 0.5 parts by mass or more and 15 parts by mass or less, when the mass of the composition excluding the mass of the solvent (S) described below is taken as 100 parts by mass.

<Solvent (S)>
The composition may contain a solvent (S) for the purpose of adjusting the coatability, etc. The type of solvent (S) is not particularly limited as long as the desired effect is not impaired.

Suitable examples of the solvent (S) 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 (HO-CH ₂ CH ₂ CH ₂ -O-CH ₃ ), propylene glycol monomethyl ether (HO-C(CH ₃ )HCH ₂ -O-CH ₃ , or H ₃ C-O-C(CH ₃ )HCH ₂ -OH), propylene glycol monoethyl ether (HO-CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₃ ), propylene glycol monoethyl ether (HO-C(CH ₃ )HCH ₂ -O-CH ₂ CH ₃ ), , or H ₃ CH ₂ C—O—C(CH ₃ )HCH ₂ —OH), propylene glycol mono-n-propyl ether (HO-CH ₂ CH ₂ CH ₂ —O-CH ₂ CH ₂ CH ₃ ), propylene glycol mono-n-propyl ether (HO-C(CH ₃ )HCH ₂ —O-CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ C—O—C(CH ₃ )HCH ₂ —OH), propylene glycol mono-n-butyl ether (HO-CH ₂ CH ₂ CH ₂ —O-CH ₂ CH ₂ CH ₂ CH ₃ ), propylene glycol mono-n-butyl ether (HO-C(CH ₃ )HCH ₂ —O-CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C—O—C(CH ₃ )HCH ₂ —OH), dipropylene glycol monoethyl ether (HO—(CH ₂ CH ₂ CH ₂ —O) ₂ —CH ₃ ), dipropylene glycol monomethyl ether (HO—(C(CH ₃ )HCH ₂ —O) ₂ —CH ₃ , or H ₃ C—O—(C(CH ₃ )HCH ₂ —O) ₂ —H), dipropylene glycol monoethyl ether (HO—(CH ₂ CH ₂ CH ₂ —O) ₂ —CH ₂ CH ₃ ), dipropylene glycol monoethyl ether (HO—(C(CH ₃ )HCH ₂ —O) ₂ —CH ₂ CH ₃ , or H ₃ CH ₂ C—O—(C(CH ₃ )HCH ₂ —O) ₂ —H -H), dipropylene glycol mono-n-propyl ether (HO- _{( CH2CH2CH2 - O} ) _{2 - CH2CH2CH3} , _{or H3CH2CH2C} -O-(CH2CH2CH2 _- O) ₂ -H), dipropylene glycol mono-n-propyl ether (HO-(C( _CH3 ) _{HCH2 - O ) 2} - _CH2CH2CH3 , or H3CH2CH2C-O-(C( _CH3 ) _{HCH2 -} O _{) 2} -H), dipropylene glycol mono _- n-butyl ether (HO-( _{CH2CH2CH2 -} O) _{2 -} CH2CH2CH2CH3, or _H3CH2CH2CH2C -O-(C( _{CH3 ) HCH2 -} O _{)2 - H ) .} C—O—(CH ₂ CH ₂ CH ₂ —O) ₂ —H), dipropylene glycol mono-n-butyl ether (HO—(C(CH ₃ )HCH ₂ —O) ₂ —CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C—O—(C(CH ₃ )HCH ₂ —O) ₂ —H), tripropylene glycol monomethyl ether (HO—(CH ₂ CH ₂ CH ₂ —O) ₃ —CH ₂ CH ₃ ), tripropylene glycol monomethyl ether (H ₃ C—O—(C(CH ₃ )HCH ₂ —O) ₃ —H), tripropylene glycol monoethyl ether (HO—(CH ₂ CH ₂ CH ₂ —O) ₃ —CH ₂ CH ₃ ), tripropylene glycol monoethyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₃ -CH ₂ CH ₃ , or H ₃ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) ₃ -H), and other (poly)alkylene glycol monoalkyl ether acetates; 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, propylene glycol monoethyl ether acetate, and other (poly)alkylene glycol monoalkyl ether acetates; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol methyl ethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol diethyl ether, tetrahydrofuran, and other ethers; methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, and other ketones; 2-hydro alkyl lactic acid esters 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, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, ethyl acetate, n-propyl acetate, isopropyl acetate, acetic acid Examples of the esters include 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, and N,N-dimethylacetamide, with (poly)alkylene glycol monoalkyl ether acetates being preferred.

In order to ensure good application by the inkjet printing method, it is preferable that the solvent (S) contains a solvent having a boiling point of 140°C or higher at atmospheric pressure, and it is more preferable that the solvent (S1) contains a high-boiling point solvent having a boiling point of 170°C or higher at atmospheric pressure.

Specific examples of the solvent having a boiling point of 140° C. or higher under atmospheric pressure include ethylene glycol mono-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 (HO-CH ₂ CH ₂ CH ₂ -O-CH ₃ ), propylene glycol monoethyl ether (HO-CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₃ ), propylene glycol mono-n-propyl ether (HO-CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₂ CH ₃ ), propylene glycol mono-n-propyl ether (HO-C(CH ₃ )HCH ₂ -O-CH ₂ CH ₂ CH _{3 )} , or H ₃ CH ₂ CH ₂ C—O—C(CH ₃ )HCH ₂ —OH), propylene glycol mono-n-butyl ether (HO—CH ₂ CH ₂ CH ₂ —O—CH ₂ CH ₂ CH ₂ CH ₃ ), propylene glycol mono-n-butyl ether (HO—C(CH ₃ )HCH ₂ —O—CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C—O—C(CH ₃ )HCH ₂ —OH), dipropylene glycol monoethyl ether (HO—(CH ₂ CH ₂ CH ₂ —O) ₂ —CH ₃ ), dipropylene glycol monomethyl ether (HO—(C(CH ₃ )HCH ₂ —O) ₂ —CH ₃ , or H ₃ C—O—(C(CH ₃ )HCH ₂ -O) ₂ -H), dipropylene glycol monoethyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₃ ), dipropylene glycol monoethyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₂ CH ₃ , or H ₃ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) ₂ -H), dipropylene glycol mono-n-propyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ C-O-(CH ₂ CH ₂ CH ₂ -O) ₂ -H), dipropylene glycol mono-n-propyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) ₂ -H), dipropylene glycol mono-n-butyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C-O-(CH ₂ CH ₂ CH ₂ -O) ₂ -H), dipropylene glycol mono-n-butyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) _2-H -H), tripropylene glycol monomethyl ether (HO-(CH2CH2CH2 _- O) _{3 -CH2CH3 )} , tripropylene glycol monomethyl ether ( _H3C -O-(C( _CH3 ) _{HCH2 -} O) ₃ -H), tripropylene glycol monoethyl ether (HO- ₍ CH2CH2CH2 _- O) _{3 -} CH2CH3), tripropylene glycol monoethyl ether (HO-(C( _CH3 ) _{HCH2 -} O) _{3 - CH2CH3} , or _{H3CH2C -} O-(C( _CH3 ) _{HCH2 - O} ) ₃ -H), diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, cyclohexanone, 2-heptanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, n-butyl butyrate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutanoate, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

Specific examples of the high boiling point solvent (S1) include 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 mono-n-butyl ether (HO-CH ₂ CH ₂ CH ₂ -O-CH ₂ CH ₂ CH ₂ CH ₃ ), propylene glycol mono-n-butyl ether (HO-C(CH ₃ )HCH ₂ -O-CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C-O-C(CH ₃ )HCH ₂ -OH), dipropylene glycol monoethyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₃ ), dipropylene glycol monomethyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₃ , or H ₃ C-O-(C(CH ₃ )HCH ₂ -O) ₂ -H), dipropylene glycol monoethyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₃ ), dipropylene glycol monoethyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₂ CH ₃ , or H ₃ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) ₂ -H), dipropylene glycol mono-n-propyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₂ -CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ C-O-(CH ₂ CH ₂ CH ₂ -O) ₂ -H), dipropylene glycol mono-n-propyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₂ -CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) _{2 -H), dipropylene glycol mono-n-butyl ether (HO-(CH 2 CH 2 CH 2 -O) 2 -CH 2 CH 2 CH 2 CH 3 , or H 3 CH 2 CH 2 CH 2 C-O-(CH 2 CH 2 CH 2 -O) 2 -H), dipropylene glycol mono-n-butyl ether (HO-(CH 2 CH 2 CH 2 -O ) 2 -CH 2 CH 2 CH} 2 CH 3 , or H ₃ CH ₂ CH 2 CH 2 C-O-(CH ₂ CH ₂ CH ₂ -O) ₂ -H). -CH ₂ CH ₂ CH ₂ CH ₃ , or H ₃ CH ₂ CH ₂ CH ₂ C-O-(C(CH ₃ )HCH ₂ -O) ₂ -H), tripropylene glycol monomethyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₃ -CH ₂ CH ₃ ), tripropylene glycol monomethyl ether (H ₃ C-O-(C(CH ₃ )HCH ₂ -O) ₃ -H), tripropylene glycol monoethyl ether (HO-(CH ₂ CH ₂ CH ₂ -O) ₃ -CH ₂ CH ₃ ), tripropylene glycol monoethyl ether (HO-(C(CH ₃ )HCH ₂ -O) ₃ -CH ₂ CH ₃ , or H ₃ CH ₂ C-O-(C( _CH )HCH ₂ -O) ₃ -H), diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether, dipropylene glycol diethyl ether, ethyl hydroxyacetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, methyl acetoacetate, ethyl acetoacetate, ethyl 2-oxobutanoate, and N-methylpyrrolidone.

In terms of making it easier to obtain the desired effect, the ratio of the mass of the solvent having a boiling point of 140°C or higher, or the mass of the high-boiling point solvent (S1) having a boiling point of 170°C or higher to the mass of the solvent (S) is preferably 20% by mass or higher, more preferably 30% by mass or higher, even more preferably 50% by mass or higher, even more preferably 70% by mass or higher, particularly preferably 90% by mass or higher, and most preferably 100% by mass.

The content of the solvent (S) is preferably such that the concentration of the components other than the solvent (S) in the composition is 1% by mass or more and 99% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less.

<Other ingredients>
The composition may contain various additives as other components other than the above components, as necessary, such as sensitizers, curing accelerators, fillers, dispersants, adhesion promoters such as silane coupling agents, antioxidants, aggregation inhibitors, thermal polymerization inhibitors, defoamers, surfactants, etc.
The amounts of these additives used are appropriately determined taking into consideration the amounts in which these additives are usually used in the composition.

<Photosensitive composition>
The photosensitive composition contains a photopolymerizable compound (A), inorganic fine particles (B), and an initiator (C). The initiator (C) is a component that cures the photopolymerizable compound.
The preferred embodiments and amounts of the photopolymerizable compound (A) and the inorganic fine particles (B) used are as described above for the above composition.

The photosensitive composition may further contain one or more components selected from the group consisting of the plasticizer (D), the nitrogen-containing compound (E), the triazine compound (F), the solvent (S), and other components described above for the above compositions. The preferred aspects and amounts of these components used are as described above for the above compositions.

<Initiator (C)>
In order to cure the photopolymerizable compound (A), the photosensitive composition contains an initiator (C). When the photopolymerizable compound (A) has a radical polymerizable group, a radical polymerization initiator (C1) is used as the initiator (C). When the photopolymerizable compound (A) has a cationic polymerizable group, a cationic polymerization initiator (C2) is used as the initiator (C). A photoinitiator is used as the initiator (C) because it can perform position-selective curing of the photosensitive composition and there is no concern about deterioration, volatilization, sublimation, etc., of the components of the photosensitive composition due to heat.
The initiator (C) is not particularly limited, and various conventionally known polymerization initiators can be used.

Specific examples of photoradical polymerization initiators useful as the radical polymerization initiator (C1) 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-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, O-acetyl-1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone oxime, (9-ethyl-6-nitro-9H-carbazol-3-yl)[4-(2-methoxy-1-methylethoxy)-2-methylphenyl]methanone O-acetyl oxime, 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]-1-octanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 4-benzoyloxyimino Zoyl-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-propoxythioxane thion, thioxanthene, 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, 2-hydroxy-2-methylpropiophenone, dichloroacetophenone, trichloroacetophenone acetophenone, p-tert-butylacetophenone, 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 styrylphenyl-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 photoradical polymerization initiators can be used alone or in combination of two or more.

Among the photoradical polymerization initiators, oxime ester compounds are preferred in terms of the sensitivity of the photosensitive composition.
The oxime ester compound is preferably a compound having a partial structure represented by the following formula (c1).

（式（ｃ１）中、
ｎ１は、０、又は１であり、
Ｒ^ｃ２は、一価の有機基であり、
Ｒ^ｃ３は、水素原子、置換基を有してもよい炭素原子数１以上２０以下の脂肪族炭化水素基、又は置換基を有してもよいアリール基であり、
＊は結合手である。）

(In formula (c1),
n1 is 0 or 1,
R ^c2 is a monovalent organic group;
R ^c3 is a hydrogen atom, an aliphatic hydrocarbon group having from 1 to 20 carbon atoms which may have a substituent, or an aryl group which may have a substituent,
* is a bond.)

The compound having the partial structure represented by formula (c1) preferably has a carbazole skeleton, a fluorene skeleton, a diphenyl ether skeleton, or a phenyl sulfide skeleton.
The compound having the partial structure represented by formula (c1) preferably has one or two partial structures represented by formula (c1).

An example of a compound having a partial structure represented by formula (c1) is a compound represented by the following formula (c2).

（式（ｃ２）中、Ｒ^ｃ１は、下記式（ｃ３）、（ｃ４）、又は（ｃ５）で表される基であり、
ｎ１は、０、又は１であり、
Ｒ^ｃ２は、一価の有機基であり、
Ｒ^ｃ３は、水素原子、置換基を有してもよい炭素原子数１以上２０以下の脂肪族炭化水素基、又は置換基を有してもよいアリール基である。）

In formula (c2), R ^c1 is a group represented by the following formula (c3), (c4), or (c5):
n1 is 0 or 1,
R ^c2 is a monovalent organic group;
R ^c3 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, or an aryl group which may have a substituent.

（式（ｃ３）中、Ｒ^ｃ４及びＲ^ｃ５は、それぞれ独立に、１価の有機基であり、
ｎ２は、０以上３以下の整数であり、
ｎ２が２又は３の場合、複数のＲ^ｃ５は同一でも異なっていてもよく、複数のＲ^ｃ５は互いに結合して環を形成してもよい。
＊は結合手である。）

In formula (c3), R ^c4 and R ^c5 each independently represent a monovalent organic group.
n2 is an integer of 0 to 3,
When n2 is 2 or 3, multiple R ^c5 may be the same or different, and multiple R ^c5 may be bonded to each other to form a ring.
* is a bond.)

（式（ｃ４）中、Ｒ^ｃ６及びＲ^ｃ７は、それぞれ独立に、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鎖状アルコキシ基、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^ｃ６とＲ^ｃ７とは互いに結合して環を形成してもよく、
Ｒ^ｃ７とフルオレン骨格中のベンゼン環とが互いに結合して環を形成してもよく、
Ｒ^ｃ８は、ニトロ基、又は１価の有機基、であり、
ｎ３は、０以上４以下の整数であり、
＊は結合手である。）

In formula (c4), R ^c6 and R ^c7 each independently represent a chain alkyl group which may have a substituent, a chain alkoxy group which may have a substituent, a cyclic organic group which may have a substituent, or a hydrogen atom;
R ^c6 and R ^c7 may be bonded to each other to form a ring;
R ^c7 and a benzene ring in the fluorene skeleton may be bonded to each other to form a ring,
R ^c8 is a nitro group or a monovalent organic group;
n3 is an integer of 0 to 4,
* is a bond.)

（式（ｃ５）中、Ｒ^ｃ９は、１価の有機基、ハロゲン原子、ニトロ基、又はシアノ基であり、
Ａは、Ｓ又はＯであり、
ｎ４は、０以上４以下の整数であり、
＊は結合手である。）

In formula (c5), R ^c9 represents a monovalent organic group, a halogen atom, a nitro group, or a cyano group;
A is S or O;
n4 is an integer from 0 to 4,
* is a bond.)

In formula (c3), R ^c4 is a monovalent organic group. R ^c4 can be selected from various organic groups as long as it does not impair the object of the present invention. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms of the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
Suitable examples of R ^c4 include an alkyl group having 1 to 20 carbon atoms and optionally having a substituent, a cycloalkyl group having 3 to 20 carbon atoms and optionally having a substituent, a saturated aliphatic acyl group having 2 to 20 carbon atoms and optionally having a substituent, an alkoxycarbonyl group having 2 to 20 carbon atoms and optionally having a substituent, 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 and optionally having 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 and optionally having a substituent, a heterocyclyl group which may have a substituent, and a heterocyclylcarbonyl group which may have a substituent.

Among R ^c4 , an alkyl group having 1 to 20 carbon atoms is preferred. The alkyl group may be linear or branched. In view of good solubility of the compound represented by formula (c3) in the photosensitive composition, the number of carbon atoms of the alkyl group represented by R ^c4 is preferably 2 or more, more preferably 5 or more, and particularly preferably 7 or more. In view of good compatibility of the compound represented by formula (c3) with other components in the photosensitive composition, the number of carbon atoms of the alkyl group represented by R ^c4 is preferably 15 or less, more preferably 10 or less.

When R ^c4 has a substituent, suitable examples of the substituent include a hydroxyl group, an alkyl group having from 1 to 20 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an aliphatic acyl group having from 2 to 20 carbon atoms, an aliphatic acyloxy group having from 2 to 20 carbon atoms, a phenoxy group, a benzoyl group, a benzoyloxy group, a group represented by -PO(OR) ₂ (R is an alkyl group having from 1 to 6 carbon atoms), a halogen atom, a cyano group, and a heterocyclyl group.

When R ^c4 is a heterocyclyl group, the heterocyclyl group may be an aliphatic heterocyclic group or an aromatic heterocyclic group. When R ^c4 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 a 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 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.
When R ^c4 is a heterocyclyl group, examples of the substituent that the heterocyclyl group may have include a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, a nitro group, and the like.

Specific preferred examples of R ^c4 described above 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 neopentyl group, a pentan-3-yl group, a sec-pentyl group, a tert-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and a 2-ethylhexyl group.
Furthermore, from the viewpoint of good solubility of the compound represented by formula (c3) in the photosensitive composition, an n-octyl group and a 2-ethylhexyl group are preferred, and a 2-ethylhexyl group is more preferred.

In formula (c3), R ^c5 is a monovalent organic group. R ^c5 can be selected from various organic groups as long as it does not impair the object of the present invention. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms of the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
Examples of monovalent organic groups suitable for R ^c5 include 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 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 1 or 2 organic groups, a morpholin-1-yl group, a piperazin-1-yl group, a halogen atom, a nitro group, a cyano group, HX ₂ C- or H ₂ Examples of the substituent include a substituent containing a group represented by XC- (wherein each X is independently a halogen atom).

When R ^c5 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 ^c5 is an alkyl group, it may be a straight chain or a branched chain. Specific examples of when R ^c5 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 ^c5 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 ^c5 is an alkoxy group, the number of carbon atoms of the alkoxy group is preferably 1 or more and 20 or less, and more preferably 1 or more and 6 or less. When R ^c5 is an alkoxy group, it may be a straight chain or a branched chain. Specific examples of when R ^c5 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 ^c5 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 ^c5 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 ^c5 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 ^c5 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 ^c5 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 from 2 to 21, and more preferably from 2 to 7. Specific examples of when R ^c5 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 ^c5 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 ^c5 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 ^c5 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 ^c5 is a phenylalkyl group, the number of carbon atoms of the phenylalkyl group is preferably 7 or more and 20 or less, more preferably 7 or more and 10 or less. When R ^c5 is a naphthylalkyl group, the number of carbon atoms of the naphthylalkyl group is preferably 11 or more and 20 or less, more preferably 11 or more and 14 or less. Specific examples of when R ^c5 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 ^c5 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 ^c5 is a phenylalkyl group or a naphthylalkyl group, R ^c5 may further have a substituent on the phenyl group or the naphthyl group.

When R ^c5 is a heterocyclyl group, the heterocyclyl group is the same as when R ^c4 in formula (c3) is a heterocyclyl group, and the heterocyclyl group may further have a substituent.
When R ^c5 is a heterocyclylcarbonyl group, the heterocyclyl group contained in the heterocyclylcarbonyl group is the same as when R ^c5 is a heterocyclyl group.

When R ^c5 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, etc. Specific examples of these suitable organic groups are the same as those of R ^c5 . 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 ^c5 further have a substituent include a substituent containing a group represented by HX ₂ C- or H ₂ XC- (for example, a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC-, a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC-), 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 piperazine-1-yl group, a benzoyl group, a halogen, a nitro group, and a cyano group. When the phenyl group, naphthyl group, and heterocyclyl group included in R ^c5 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, and is preferably from 1 to 4. When the phenyl group, naphthyl group, and heterocyclyl group included in R ^c5 have multiple substituents, the multiple substituents may be the same or different.

When the benzoyl group included in R ^c5 further has a substituent, examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a morpholin-1-yl group, a piperazine-1-yl group, a 2-thenoyl group (thiophen-2-ylcarbonyl group), a furan-3-ylcarbonyl group, and a phenyl group.

The halogen atom represented by X may be a fluorine atom, a chlorine atom, a bromine atom, etc., and is preferably a fluorine atom.

Examples of the substituent containing a group represented by HX ₂ C- or H ₂ XC- include a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC-, a group having a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC-, a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC-, and a group having a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC-. Of these, a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC-, or a group having a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- is more preferred.

Examples of groups having a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC- include aromatic groups substituted with a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC- (e.g., phenyl group, naphthyl group, etc.), and cycloalkyl groups substituted with a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC- (e.g., cyclopentyl group, cyclohexyl group, etc.), with aromatic groups substituted with a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC- being preferred.

Examples of groups having a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- include aromatic groups substituted with a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- (e.g., phenyl group, naphthyl group, etc.), alkyl groups substituted with a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- (e.g., methyl group, ethyl group, n-propyl group, i-propyl group, etc.), and cycloalkyl groups substituted with a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- (e.g., cyclopentyl group, cyclohexyl group, etc.), and the like. An aromatic group substituted with a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC- is preferred.

Also preferred as R ^c5 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 ^c5 may have.

Among the monovalent organic groups, R ^c5 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 in 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 in 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 in 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.

In the group represented by formula (c3), when a plurality of R ^c5 are present and the plurality of R ^c5 are bonded to each other to form a ring, examples of the ring formed include a hydrocarbon ring and a heterocycle. Examples of heteroatoms contained in a heterocycle include N, O, and S. A particularly preferred ring formed by bonding a plurality of R ^c5 to each other is an aromatic ring. Such an aromatic ring may be an aromatic hydrocarbon ring or an aromatic heterocycle. Such an aromatic ring is preferably an aromatic hydrocarbon ring. Specific examples of the case where a plurality of R ^c5 are bonded to each other to form a benzene ring in formula (c3) are shown below.

In the group represented by formula (c4), R ^c8 is a nitro group or a monovalent organic group. R ^c8 is bonded to a 6-membered aromatic ring different from the aromatic ring bonded to the group represented by -(CO) _n1 - on the fused ring in formula (c4). In formula (c4), the bonding position of R ^c8 is not particularly limited. When the group represented by formula (c4) has one or more R ^c8 , it is preferable that one of the one or more R ^c8 is bonded to the 7th position of the fluorene skeleton, because the synthesis of the compound represented by formula (c4) is easy. That is, when the group represented by formula (c4) has one or more R ^c8 , the group represented by formula (c4) is preferably represented by the following formula (c6). When there are multiple R ^c8s , the multiple R ^c8s may be the same or different.

（式（ｃ６）中、Ｒ^ｃ６、Ｒ^ｃ７、Ｒ^ｃ８、ｎ３は、それぞれ式（ｃ４）におけるＲ^ｃ６、Ｒ^ｃ７、Ｒ^ｃ８、ｎ３と同様である。）

(In formula (c6), R ^c6 , R ^c7 , R ^c8 , and n3 are the same as R ^c6 , R ^c7 , R ^c8 , and n3 in formula (c4), respectively.)

When R ^c8 is a monovalent organic group, R ^c8 is not particularly limited as long as it does not impair the object of the present invention. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms of the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
When R ^c8 is a monovalent organic group, preferred examples thereof include the same groups as the preferred examples of the monovalent organic group as R ^c5 in formula (c3).

In formula (c4), R ^c6 and R ^c7 are each a chain alkyl group which may have a substituent, a chain alkoxy group which may have a substituent, a cyclic organic group which may have a substituent, or a hydrogen atom. R ^c6 and R ^c7 may be bonded to each other to form a ring. Among these groups, R ^c6 and R ^c7 are preferably a chain alkyl group which may have a substituent. When R ^c6 and R ^c7 are a chain alkyl group which may have a substituent, the chain alkyl group may be a straight chain alkyl group or a branched chain alkyl group.

When R ^c6 and R ^c7 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 ^c6 and R ^c7 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 ^c6 and R ^c7 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 ^c6 and R ^c7 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 an alkoxy group, a cyano group, a halogen atom, a halogenated alkyl group, 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 ^c8 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 ^c8 is a heterocyclyl group. When R ^c8 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 ^c6 and R ^c7 are chain alkoxy groups having no substituents, the number of carbon atoms in the chain alkoxy group is preferably from 1 to 20, more preferably from 1 to 10, and particularly preferably from 1 to 6. Specific examples of when R ^c6 and R ^c7 are chain alkoxy groups 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 ^c6 and R ^c7 are alkoxy groups, the alkoxy groups 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 ^c6 and R ^c7 are chain alkoxy groups having a substituent, the substituent that the alkoxy group may have is the same as when R ^c6 and R ^c7 are chain alkyl groups.

When R ^c6 and R ^c7 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 ^c6 and R ^c7 are cyclic organic groups, the substituents that the cyclic organic group may have are the same as those when R ^c6 and R ^c7 are chain alkyl groups.

When R ^c6 and R ^c7 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 ^c6 and R ^c7 are alicyclic hydrocarbon groups, the alicyclic hydrocarbon group may be monocyclic or polycyclic. The number of carbon atoms of the alicyclic 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.

When R ^c6 and R ^c7 are heterocyclyl groups, examples of the heterocyclyl group include the same groups as the heterocyclyl group as R ^c5 in formula (c3).

R ^c6 and R ^c7 may be bonded to each other to form a ring. The group consisting of the ring formed by R ^c6 and R ^c7 is preferably a cycloalkylidene group. When R ^c6 and R ^c7 are bonded to form a cycloalkylidene group, the ring constituting the cycloalkylidene group is preferably a 5-membered to 6-membered ring, more preferably a 5-membered ring.

When R ^c7 forms a ring together with the benzene ring of the fluorene skeleton, the ring may be an aromatic ring or an aliphatic ring.

When the group formed by combining ^Rc6 and ^Rc7 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 ^c6 and R ^c7 , 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 ^c6 and R ^c7 have as substituents. When ^A2 is an alkoxycarbonyl group, examples of the alkoxycarbonyl group are the same as the alkoxycarbonyl groups which ^Rc6 and ^Rc7 have as substituents.

Preferable specific examples of R ^c6 and R ^c7 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 ^c6 and R ^c7 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.

In formula (c5), it is particularly preferable that A is S, since this makes it easier to obtain a photopolymerization initiator with excellent sensitivity.

In formula (c5), R ^c9 represents a monovalent organic group, a halogen atom, a nitro group, or a cyano group.
When R ^c9 in formula (c5) is a monovalent organic group, it can be selected from various organic groups as long as it does not impair the object of the present invention. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms in the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
In formula (c5), when R ^c9 is an organic group, suitable examples thereof include the same monovalent organic groups as R ^c5 in formula (c3).

Among R ^c9 , 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, a nitro group, and a benzofuranylcarbonyl group which may have a substituent, 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 (c5), n4 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 n4 is 1, the position at which R ^c9 is bonded is preferably the para position with respect to the bond at which the phenyl group to which R ^c9 is bonded is bonded to an oxygen atom or a sulfur atom.

In formulas (c1) and (c2), the monovalent organic group represented by R ^c2 is not particularly limited as long as it does not impair the object of the present invention. As the organic group, a carbon atom-containing group is preferable, and a group consisting of one or more carbon atoms and one or more atoms selected from the group consisting of H, O, S, Se, N, B, P, Si, and halogen atoms is more preferable. The number of carbon atoms in the carbon atom-containing group is not particularly limited, and is preferably 1 to 50, more preferably 1 to 20.
Suitable examples of the monovalent organic group as R ^c2 include the same groups as the monovalent organic group as R ^c5 in formula (c3). Specific examples of these groups are the same as those described for R ^c5 in formula (c3).
Also preferred as R ^c2 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 when the phenyl group, naphthyl group, and heterocyclyl group included in R ^c5 in formula (c3) further have a substituent.

Among the organic groups, R ^c2 is preferably a substituent containing a group represented by HX ₂ C- or H ₂ XC-, an alkyl group, a cycloalkyl group, a phenyl group which may have a substituent, a cycloalkylalkyl group, or a phenylthioalkyl group which may have a substituent on the aromatic ring. The alkyl group, the phenyl group which may have a substituent, the number of carbon atoms of the cycloalkyl group contained in the cycloalkylalkyl group, the number of carbon atoms of the alkylene group contained in the cycloalkylalkyl group, the cycloalkylalkyl group, the number of carbon atoms of the alkylene group contained in the phenylthioalkyl group which may have a substituent on the aromatic ring, or the phenylthioalkyl group which may have a substituent on the aromatic ring are the same as R ^c5 in formula (c3).

Also preferred as R ^c2 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（ｃ７）及び（ｃ８）中、Ｒ^ｃ１０及びＲ^ｃ１１は、それぞれ独立に、１価の有機基であり、
ｎ５は０以上４以下の整数であり、
Ｒ^ｃ１０及びＲ^ｃ１１がベンゼン環上の隣接する位置に存在する場合、Ｒ^ｃ１０とＲ^ｃ１１とが互いに結合して環を形成してもよく、
Ｒ^ｃ１２は、１価の有機基であり、
ｎ６は１以下８以下の整数であり、
ｎ７は１以上５以下の整数であり、
ｎ８は０以上（ｎ７＋３）以下の整数である。） Furthermore, as R ^c2 , a group represented by the following formula (c7) or (c8) is also preferable.

In formulas (c7) and (c8), R ^c10 and R ^c11 each independently represent a monovalent organic group.
n5 is an integer of 0 to 4,
When R ^c10 and R ^c11 are present at adjacent positions on the benzene ring, R ^c10 and R ^c11 may be bonded to each other to form a ring;
R ^c12 is a monovalent organic group;
n6 is an integer of 1 to 8,
n7 is an integer of 1 to 5,
n8 is an integer between 0 and (n7+3).

The organic groups represented by R ^c10 and R ^c11 in formula (c7) are the same as R ^c8 in formula (c4). R ^c10 is preferably a halogenated alkoxy group containing a group represented by HX ₂ C- or H ₂ XC-, a halogenated alkyl group containing a group represented by HX ₂ C- or H ₂ XC-, an alkyl group, or a phenyl group. When R ^c10 and R ^c11 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 (c7) in which R ^c10 and R ^c11 form a ring include a naphthalene-1-yl group and a 1,2,3,4-tetrahydronaphthalene-5-yl group.
In the above formula (c7), n5 is an integer of 0 or more and 4 or less, preferably 0 or 1, and more preferably 0.

In the above formula (c8), R ^c12 is an organic group. Examples of the organic group include the same groups as those described for R ^c8 in formula (c4). Among the organic groups, an alkyl group is preferred. 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 ^c12 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 preferred.

In the above formula (c8), n7 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 (c8), n8 is an integer of 0 or more and (n7+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 (c8), n6 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 (c2), R ^c3 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, or an aryl group which may have a substituent. When R ^c3 is an aliphatic hydrocarbon group, preferred examples of the substituent which it may have include a phenyl group and a naphthyl group.

In formulas (c1) and (c2), preferred examples of R ^c3 include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a 2-cyclopentylethyl group, a 2-cyclobutylethyl group, a cyclohexylmethyl group, a phenyl group, a benzyl group, a methylphenyl group, and a naphthyl group. Of these, a methyl group or a phenyl group is more preferred.

Preferable specific examples of the compound represented by formula (c2) and having a group represented by formula (c3) as R ^c1 include the following compounds.

Preferable specific examples of the compound represented by formula (c2) and having a group represented by formula (c4) as R ^c1 include the following compounds.

Preferable specific examples of the compound represented by formula (c2) and having a group represented by formula (c5) as R ^c1 include the following compounds.

式（ｃ９）中、Ｒ^ｃ２１及びＲ^ｃ２２は、それぞれ独立に、アルキル基、シクロアルキル基、アリール基、炭素原子数２以上２０以下の脂肪族アシル基、又は炭素原子数７以上２０以下の芳香族アシル基である。ただし、Ｒ^ｃ２１及びＲ^ｃ２２の双方が脂肪族アシル基又は芳香族アシル基ではない。 As the radical polymerization initiator (C1), a phosphine oxide compound is also preferred because it provides good deep curing properties for the photosensitive composition. As the phosphine oxide compound, a phosphine oxide compound containing a partial structure represented by the following formula (c9) is preferred.

In formula (c9), R ^c21 and R ^c22 are each independently an alkyl group, a cycloalkyl group, an aryl group, an aliphatic acyl group having 2 to 20 carbon atoms, or an aromatic acyl group having 7 to 20 carbon atoms, provided that both R ^c21 and R ^c22 are not aliphatic acyl groups or aromatic acyl groups.

The number of carbon atoms of the alkyl group represented by R ^c21 and R ^c22 is preferably 1 or more and 12 or less, more preferably 1 or more and 8 or less, and still more preferably 1 or more and 4 or less. The alkyl group represented by R ^c21 and R ^c22 may be linear or branched.
Specific examples of the 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 tert-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2,4,4-trimethylpentyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, and an n-dodecyl group.

The number of carbon atoms in the cycloalkyl group represented by ^Rc21 and ^Rc22 is preferably 5 to 12. Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, and a cyclododecyl group.

The number of carbon atoms of the aryl group represented by R ^c21 and R ^c22 is preferably 6 or more and 12 or less. The aryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Specific examples of the aryl group include a phenyl group and a naphthyl group.

The number of carbon atoms of the aliphatic acyl group represented by R ^c21 and R ^c22 is 2 or more and 20 or less, preferably 2 or more and 12 or less, more preferably 2 or more and 8 or less, and still more preferably 2 or more and 6 or less. The aliphatic acyl group may be linear or branched.
Specific examples of the aliphatic acyl group include an acetyl group, a propionyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, a nonanoyl group, a decanoyl group, an undecanoyl group, a dodecanoyl group, a tridecanoyl group, a tetradecanoyl group, a pentadecanoyl group, a hexadecanoyl group, a heptadecanoyl group, an octadecanoyl group, a nonadecanoyl group, and an icosanoyl group.

The number of carbon atoms in the aromatic acyl group represented by R ^c21 and R ^c22 is 7 or more and 20 or less. The aromatic acyl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms. Specific examples of the aromatic acyl group include a benzoyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,6-dimethylbenzoyl group, a 2,6-dimethoxybenzoyl group, a 2,4,6-trimethylbenzoyl group, an α-naphthoyl group, and a β-naphthoyl group.

Preferable specific examples of the phosphine oxide compound containing the structural portion represented by formula (c9) include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide.
From the viewpoint of deep curing properties of the photosensitive composition, it is also preferable that the phosphine oxide compound containing the structural moiety represented by formula (c9) is used together with an α-hydroxyalkylphenone initiator such as 2-hydroxy-2-methylpropiophenone.
When a phosphine oxide compound having a structural moiety represented by formula (c9) is used in combination with an α-hydroxyalkylphenone-based initiator such as 2-hydroxy-2-methylpropiophenone, the ratio of the mass of the phosphine oxide compound having a structural moiety represented by formula (c9) to the total mass of both is preferably 20 mass% or more and 80 mass% or less, more preferably 30 mass% or more and 70 mass% or less, and even more preferably 40 mass% or more and 60 mass% or less.

As the cationic polymerization initiator (C2), any conventionally known cationic polymerization initiator can be used without any particular limitation. Typical examples of the cationic polymerization initiator (C2) include onium salts. Examples of the cationic polymerization initiator (C2) include oxonium salts, ammonium salts, phosphonium salts, sulfonium salts, and iodonium salts, with sulfonium salts and iodonium salts being preferred, and sulfonium salts being more preferred.

The content of the initiator (C) in the photosensitive composition is not particularly limited. The content of the initiator (C) is appropriately determined depending on the type of the radical polymerizable group or the cationic polymerizable group and the type of the initiator (C).
The content of the initiator (C) in the photosensitive composition is preferably 0.01 parts by mass or more and 20 parts by mass or less, more preferably 0.1 parts by mass or more and 15 parts by mass or less, and even more preferably 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the photosensitive composition excluding the mass of the solvent (S) described below.

The photosensitive composition is obtained by uniformly mixing and dispersing the desired amounts of the photopolymerizable compound (A), inorganic fine particles (B), initiator (C), and optional components that are added as needed.

<Production method of cured product>
The photosensitive composition described above is molded into a desired shape, and then exposed to light depending on the type of initiator (C) to produce a cured product.

The method for molding the photosensitive composition is not particularly limited and may be appropriately selected depending on the shape of the cured product. Examples of the molding method include coating and casting into a mold.
Hereinafter, a method for producing a cured film will be described as a representative example of a method for producing a cured product.

First, the photosensitive composition is applied onto a desired substrate to form a coating film, and then, if necessary, at least a portion of the solvent (S) is removed from the coating film to form a coating film.

The method of applying the photosensitive composition onto the substrate is not particularly limited. For example, the curable composition can be applied onto the substrate to a desired thickness using a contact transfer type application device such as a roll coater, a reverse coater, a bar coater, or a slit coater, or a non-contact type application device such as a spinner (rotary application device) or a curtain flow coater to form a coating film.
In addition, printing methods such as screen printing and inkjet printing can also be used to form the coating film. As described above, the photosensitive composition is unlikely to dry rapidly, thicken, or solidify in an inkjet head. Therefore, by using the photosensitive composition as an inkjet ink, coating by inkjet printing can be performed well.

After the photosensitive composition is applied onto the substrate, it is preferable to bake the coating film as necessary to remove at least a portion of the solvent (S) from the coating film. The baking temperature is appropriately determined taking into consideration the boiling point of the solvent (S) and the like. Baking may be performed at a low temperature under reduced pressure conditions.

The baking method is not particularly limited, and examples include a method of drying using a hot plate at a temperature of 80°C to 150°C, preferably 85°C to 120°C, for a time of 60 seconds to 500 seconds.

The thickness of the coating film formed in the above manner is not particularly limited. The thickness of the coating film is appropriately determined depending on the application of the cured film. The thickness of the coating film is typically adjusted appropriately so that a cured film having a thickness of preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 5 μm or less, is formed.

After forming a coating film using the above method, a cured film can be obtained by exposing the coating film to light.

The conditions for exposing the coating film are not particularly limited as long as the curing proceeds well. The exposure is carried out, for example, by irradiating the coating film with active energy rays such as ultraviolet rays and excimer laser light. The amount of energy radiation to be irradiated is not particularly limited, but may be, for example, 30 mJ/ ^cm2 or more and 5000 mJ/ ^cm2 or less. After the exposure, the exposed coating film may be baked by the same method as the heating after coating.

The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples.

Synthesis Example 1
A 300 mL reactor was charged with 2-phenylphenol (20.0 g, 0.118 mol), potassium carbonate (32.5 g, 0.235 mol), 2-[2-(2-chloroethoxy)ethoxy]ethanol (23.8 g, 0.141 mol), and 200 mL of dimethylformamide. After the atmosphere in the reactor was replaced with nitrogen, the reaction solution in the reactor was stirred at an internal temperature of 90° C. for 10 hours to react 2-phenylphenol with 2-[2-(2-chloroethoxy)ethoxy]ethanol.
The reaction solution was then cooled to room temperature. Water was added to the cooled reaction solution, and toluene was then added to the reaction solution to extract the product into toluene. The solvent was removed from the separated toluene layer, and the residue after solvent removal was purified by silica gel chromatography to obtain 26.8 g (yield 75%) of compound IM1.
Next, in a 300 mL reactor, compound IM1 (26.8 g, 0.089 mol), triethylamine (10.8 g, 0.106 mol), and 270 mL of tetrahydrofuran were mixed. The resulting solution was cooled in an ice bath. Acryloyl chloride (9.60 g, 0.106 mol) was added dropwise to the cooled solution while maintaining the internal temperature at 5° C. or less. The reaction solution to which acrylic acid chloride was added was stirred at room temperature for 2 hours, and then the precipitated salt was filtered. The solvent was removed from the resulting filtrate using an evaporator to obtain a viscous liquid. The resulting viscous liquid was purified by silica gel chromatography to obtain 15.7 g (yield 50%) of compound 1 as a colorless liquid. The measurement results of ¹ H-NMR of compound 1 are as follows.
^1H -NMR (DMSO): 3.52 (s, 4H), 3.63 (t, 2H), 3.72 (t, 2H), 4.12 (t, 2H), 4.20 (t, 2H), 5.90 (dd, 1H), 6.12 (dd, 1H), 6.35 (dd, 1H), 7.05-7.60 (m, 9H).

Synthesis Example 2
4,4'-thiobisbenzenethiol (20.0 g, 0.080 mol) and 100 mL of 20% aqueous sodium hydroxide solution were added to a 300 mL reactor. After replacing the atmosphere in the reactor with nitrogen, the contents of the reactor were stirred at an internal temperature of 60°C for 30 minutes. Then, ethylene glycol mono-2-chloroethyl ether (23.2 g, 0.186 mol) was dropped into the reactor, and the reaction was carried out at an internal temperature of 90°C for 4 hours. Next, the reaction liquid was cooled to room temperature while stirring. The solid precipitated by cooling was filtered and washed with water. The obtained solid was dried under reduced pressure to obtain 33.8 g (yield 99%) of compound IM2.
Next, in a 500 mL reactor, compound IM2 (33.8 g, 0.079 mol), triethylamine (19.2 g, 0.190 mol), hydroquinone (0.87 g, 0.008 mol), and 340 mL of tetrahydrofuran were mixed. The resulting solution was cooled in an ice bath. Acryloyl chloride (17.2 g, 0.190 mol) was added dropwise to the cooled solution while maintaining the internal temperature at 5° C. or less. The solution to which acrylic acid chloride was added was stirred at room temperature for 2 hours, and then the precipitated salt was filtered. The solvent was removed from the obtained filtrate using an evaporator to obtain a viscous liquid. The obtained viscous liquid was purified by silica gel chromatography to obtain 22.1 g (yield 52%) of compound 2 as a colorless liquid. The measurement results of ¹ H-NMR of compound 2 are as follows.
^1H -NMR (DMSO): 3.27 (t, 4H), 3.63 (t, 4H), 3.77 (t, 4H), 4.27 (t, 4H), 5.80 (dd, 2H), 6.15 (dd, 2H), 6.41 (dd, 2H), 7.20 (d, 4H), 7.28 (d, 4H).

Synthesis Example 3
Phenyl sulfide (50 g, 0.268 mol), paraformaldehyde (32.2 g, 1.074 mol), and 400 mL of HBr/HOAc were added to a 500 mL reactor. After replacing the inside of the reactor with nitrogen, the contents of the reactor were stirred at an internal temperature of 50° C. for 10 hours. Then, 400 mL of water was poured into the reactor, and the solid was filtered and washed with water. 100 mL of methanol was added to the obtained solid, and the mixture was stirred. Then, 500 mL of ethyl acetate/heptane mixture (1:3) was added to perform suspension washing, and the solid was filtered and washed with a small amount of methanol to obtain a solid. The solid was dried under reduced pressure to obtain 78.4 g (yield 78%) of compound IM3.
Next, in a 1000 mL reactor, compound IM3 (78.4 g, 0.211 mol), calcium carbonate (87.4 g, 0.632 mol), acrylic acid (43.55 g, 0.632 mol), and 400 mL of DMF were mixed, and the contents of the reactor were stirred at an internal temperature of 40° C. for 2 hours. The resulting solution was cooled to room temperature, 500 mL of toluene was added, and the mixture was separated with water. The solvent was removed from the resulting toluene solution using an evaporator to obtain a viscous liquid. The resulting viscous liquid was purified by silica gel chromatography and further dried under reduced pressure to obtain 56.2 g (79% yield) of compound 3 as a colorless liquid.

Synthesis Example 4
Benzyl 2-hydroxybenzoate (15.0 g, 0.066 mol), triethylamine (7.98 g, 0.079 mol), and 300 mL of tetrahydrofuran were added to a 500 mL reactor. The resulting solution was then cooled in an ice bath. Acryloyl chloride (7.14 g, 0.079 mol) was added dropwise to this solution while maintaining the internal temperature at 5° C. or less. The solution to which acrylic chloride had been added was stirred at room temperature for 3 hours, and the precipitated salt was filtered. The solvent was removed from the resulting filtrate using an evaporator. The residue after the solvent removal was purified by silica gel chromatography to obtain 14.6 g (yield 79%) of compound 4 as a colorless liquid. The measurement results of ¹ H-NMR of compound 4 are as follows.
^1H -NMR(DMSO): 5.22(s, 2H), 5.74(dd, 1H), 6.10(dd, 1H), 6.41(dd, 1H), 7.30-8.10(m, 9H)

Synthesis Example 5
Potassium carbonate (16.05 g, 0.12 mol), acrylic acid (8.37 g, 0.12 mol), and 200 mL of NMP were added to a 500 mL reactor. The resulting solution was stirred at room temperature for 10 minutes. 4-(bromomethyl)benzophenone (21.30 g, 0.08 mol) was added to this solution. The solution to which 4-(bromomethyl)benzophenone had been added was stirred at 40° C. for 2 hours, cooled to room temperature, and separated with water and toluene, and the product was extracted into the organic phase. The crude composition obtained by removing the solvent from the organic phase was purified by silica gel chromatography to obtain 20.1 g (yield 97%) of compound 5. The measurement results of ¹ H-NMR of compound 5 are as follows.
^1H -NMR(DMSO): 5.12(s, 2H), 5.83(dd, 1H), 6.12(dd, 1H), 6.41(dd, 1H), 7.30-7.81(m, 9H)

In the following Examples and Comparative Examples, the above-mentioned compounds 1 to 5 were used as the aromatic ring-containing polymerizable compound (A1), and the following compound 7 was used as the polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure. In addition, the following compound 6 was used as a comparative compound for the aromatic ring-containing polymerizable compound (A1), and the following compound 8 was used as a comparative compound for the polymerizable compound (A2).
Compound 6: Cyclohexyl acrylate compound 7 (CN2303): CN2303 manufactured by Arkema ((meth)acrylate compound having a hyperbranched structure, number of (meth)acryloyl groups: 6, mass average molecular weight (Mw): 1,400, viscosity (20°C): 320 mPa·s)
Compound 8 (DPHA): Dipentaerythritol hexaacrylate

As the inorganic fine particles (B), surface-treated titanium oxide fine particles (TiO ₂ ) having an average particle size of 10 nm and surface-treated zirconium oxide fine particles (ZrO ₂ ) having an average particle size of 10 nm were used.
As the solvent (S), the following S1 to S3 were used.
S1: Propylene glycol monomethyl ether acetate S2: Dipropylene glycol monomethyl ether S3: Equal amounts (by mass) of tripropylene glycol monomethyl ether and dipropylene glycol monomethyl ether mixed solvent

[Examples 1 to 90 and Comparative Examples 1 to 4]
The types and amounts of aromatic ring-containing polymerizable compound (A1), polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure, and inorganic fine particles (B) each having the types and amounts shown in Tables 1 and 2, and 1 part by mass of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide as an initiator (C) were dissolved and dispersed in the type of solvent (S) shown in Tables 1 to 3 such that the total mass of these components was 10 mass% based on the mass of the photosensitive composition, thereby obtaining photosensitive compositions of Examples 1 to 90 and Comparative Examples 1 to 4.

<Film unevenness evaluation>
A photosensitive composition was inkjet coated on a glass substrate (680 x 880 mm) using an inkjet device (OmniJet 200 manufactured by UniJet). The resulting coating film was heated at 100°C for 2 minutes and exposed to light at an exposure dose of 5 J/ ^cm2 . The surface condition of the cured film obtained by exposure was visually inspected to check for the presence or absence of drying unevenness (irregularities), wind unevenness, orange peel, hazy unevenness, pin marks, and horizontal stripe unevenness. The results of the evaluation of unevenness according to the following criteria are shown in Tables 1 to 3.
◎: No unevenness other than pin marks is observed. 〇: Pin marks and slight hazy unevenness are observed. ×: Unevenness other than pin marks (including hazy unevenness) is clearly observed.

Comparing Examples 1 to 90 with Comparative Examples 1 to 4, it can be seen that photosensitive compositions containing, as the photopolymerizable compound (A), an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure give cured films with reduced unevenness, whereas photosensitive compositions containing a compound other than the polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure do not give cured films with reduced unevenness.

Claims (9)

A photopolymerizable compound (A) and inorganic fine particles (B),
The composition, wherein the photopolymerizable compound (A) comprises an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure. The composition according to claim 1, wherein the polymerizable compound (A2) is a (meth)acrylate compound having a hyperbranched structure or a dendrimer structure. The composition according to claim 1 or 2, wherein the aromatic ring-containing polymerizable compound (A1) is at least one selected from the group consisting of a compound represented by the following formula (A1-1), a compound represented by the following formula (A1-2), a compound represented by the following formula (A1-3), and a compound represented by the following formula (A1-4):
R ^a101 - (X ^a103 -X ^a102 ) _ma12 - (X ^a101 ) _ma11 - Ar ^a101 - ( (X ^a104 ) _ma13 - (X ^a105 ) ) _ma14 ... (A1-1)
(In formula (A1-1), Ar ^a101 is an aromatic group having 7 to 12 carbon atoms and a valence of (ma14+1), which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a101 is a radical polymerizable group-containing group or a cationically polymerizable group-containing group; X ^a101 is O or S; X ^a102 is an alkylene group which may be interrupted by one or more O and/or S; X ^a103 is O or S; X ^a104 is O or S; X ^a105 is an alkyl group which may be interrupted by one or more O and/or S; ma11 is 0 or 1; ma12 is 0 or 1; ma13 is 0 or 1; ma14 is an integer of 0 or greater; X ^a101 , X ^a103 , and X The total number of O and/or S as ^a104 and the number of O and/or S contained in X ^a102 and X ^a105 is 3 or more.
R ^a201 -X ^a203 -R ^a202 -(X ^a201 ) _{m a21} -Ph ²¹ -S-Ph ²² -(X ^a202 ) _{m a22} -R ^a204 -X ^a204 -R ^a203 ... (A1-2)
(In formula (A1-2), R ^a201 and R ^a203 are each independently a radical polymerizable group-containing group or a cationically polymerizable group-containing group, R ^a202 and R ^a204 are each independently an alkylene group which may be interrupted by one or more O and/or S, X ^a201 , X ^a202 , X ^a203 and X ^a204 are each independently O or S, Ph ²¹ and Ph ²² are each independently a phenylene group which may be substituted with an alkyl group having 1 to 5 carbon atoms, ma21 is 0 or 1, ma22 is 0 or 1, and the compound represented by formula (A1-2) does not simultaneously have a radical polymerizable group-containing group and a cationically polymerizable group-containing group.)
R ^a301 -R ^a302 -X ^a301 -Ph ³¹ -CO-O-R ^a303 ... (A1-3)
(In formula (A1-3), R ^a301 is a radically polymerizable group-containing group or a cationically polymerizable group-containing group, X ^a301 is O or S, R ^a302 is a single bond or a divalent linking group, R ^a303 is a benzyl group or a phenethyl group, and Ph ³¹ is a phenylene group.)
(R ^a401 -X ^a401 -R ^a402 ) _ma41 -Ar ^a401 -C(=O)-Ar ^a402 -(R ^a403 -X ^a402 -R ^a404 ) _ma42 ... (A1-4)
In formula (A1-4), Ar ^a401 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma41+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; Ar ^a402 is an aromatic group having 6 to 12 carbon atoms and a valence of (ma42+1) which may be substituted with one or more groups selected from the group consisting of an alkyl group having 1 to 5 carbon atoms, a cyano group, and a halogen atom; R ^a401 and R ^a404 are each independently a radical polymerizable group-containing group or a cation polymerizable group-containing group; X ^a401 and X ^a402 are each independently O or S; R ^a402 and R Each ^a403 is independently an alkylene group, ma41 is an integer of 1 or more and 3 or less, and ma42 is an integer of 0 or more and 3 or less. The inorganic fine particles (B) contain metal oxide fine particles (B1),
The composition according to claim 1 or 2, wherein the metal oxide fine particles (B1) comprise at least one selected from the group consisting of titanium oxide fine particles, zirconium oxide fine particles, and niobium oxide fine particles. A solvent (S),
The composition according to claim 1 or 2, which is used as an ink-jet ink. A photopolymerizable compound (A), inorganic fine particles (B), and an initiator (C),
The photosensitive composition, wherein the photopolymerizable compound (A) comprises an aromatic ring-containing polymerizable compound (A1) and a polymerizable compound (A2) having a hyperbranched structure or a dendrimer structure. A cured product of the photosensitive composition according to claim 6. Coating the photosensitive composition according to claim 6 on a substrate to form a coating film;
exposing the coating film to light;
A method for producing a cured film comprising the steps of: The method for producing a cured film according to claim 8, wherein the application of the photosensitive composition is performed by an inkjet printing method.