WO2024181520A1

WO2024181520A1 - Curable composition, method for producing cured product, film, optical element, image sensor, solid-state imaging element, image display device, and radical polymerization initiator

Info

Publication number: WO2024181520A1
Application number: PCT/JP2024/007429
Authority: WO
Inventors: 雅臣牧野; 拓貴本橋
Original assignee: 富士フイルム株式会社
Priority date: 2023-03-01
Filing date: 2024-02-28
Publication date: 2024-09-06

Abstract

One embodiment of the present invention is: a curable composition that contains a radical polymerization initiator represented by formula (1), a radical curable compound, and a resin having a crosslinkable group and a graft chain; a method for producing a cured product; a film; an optical element; an image sensor; a solid-state imaging element; an image display device; and a radical polymerization initiator. In formula (1): X represents a divalent organic group; R₁₁ and R₁₂ each independently represent an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group; R₂₁ and R₂₂ each independently represent a monovalent organic group or a divalent organic group upon being linked with X; and n1 and n2 each independently represent 0 or 1.

Description

CURABLE COMPOSITION, PROCESS FOR PRODUCING CURED PRODUCT, FILM, OPTICAL ELEMENT, IMAGE SENSOR, SOLID-STATE IMAGING DEVICE, IMAGE DISPLAY DEVICE, AND RADICAL POLYMERIZATION INITIATOR

The present disclosure relates to a curable composition, a method for producing a cured product, a film, an optical element, an image sensor, a solid-state imaging element, an image display device, and a radical polymerization initiator.

Optical filters such as color filters are manufactured using a curable composition that contains a color material, a photopolymerization initiator, and a polymerizable compound. In order to achieve higher definition in recorded images, the number of pixels in color filters is increasing, and pixel patterns are becoming finer. In this situation, the use of a KrF excimer laser (248 nm), which has a shorter wavelength than i-lines, instead of the conventional i-lines (365 nm) as the wavelength light source has been considered, and a technology has been developed to improve the optical resolution and perform fine mask exposure to make patterns more fine.

As a specific example, Patent Document 1 discloses a photosensitive composition that contains a dioxime ester compound and an ultraviolet-sensitive prepolymer resin and has a fast curing rate. Patent Document 2 discloses a highly sensitive photopolymerizable composition that contains a ketoxime ester compound.

Patent Document 1: JP-T-2017-523465 A Patent Document 2: JP-A-2011-105713 A

On the other hand, it is known that the exposure dose of KrF excimer lasers is lower than that of i-lines. For this reason, compositions containing polymerization initiators that have traditionally been used in processes involving exposure to i-lines have sometimes failed to provide sufficient curing sensitivity. In addition, dispersants, resins, and other additives contained as components of curable compositions may contain, for example, amino groups in their molecules, which may act on the polymerization initiator, causing it to hydrolyze over time, resulting in a desensitization phenomenon in which the curing sensitivity decreases over time.

An object of one embodiment of the present disclosure is to provide a curable composition which has high sensitivity and excellent cross-sectional rectangularity when patterned.
Another problem to be solved by other embodiments of the present disclosure is to provide a method for producing a cured product using the curable composition, a film, an optical element, an image sensor, a solid-state imaging element, and an image display device.
Furthermore, a problem to be solved by another embodiment of the present disclosure is to provide a novel radical polymerization initiator.

Specific means for solving the problems include the following aspects.
<1> A curable composition comprising a radical polymerization initiator represented by formula (1), a radical curable compound, and a resin having a crosslinkable group and a graft chain.

In formula (1), X represents a divalent organic group; R ₁₁ and R ₁₂ each independently represent an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group; R ₂₁ and R ₂₂ each independently represent a monovalent organic group, or a divalent organic group linked to X; and n1 and n2 each independently represent 0 or 1.

<2> The curable composition according to <1>, in which R ₁₁ and R ₁₂ in formula (1) each independently represent a group having 3 or more carbon atoms.
<3> The curable composition according to <1> or <2>, in which R ₁₁ and R ₁₂ in formula (1) each independently represent a branched alkyl group or an alicyclic alkyl group.
<4> The curable composition according to any one of <1> to <3>, in which R ₁₁ and R ₁₂ in formula (1) are both the same group and are a group represented by the following formula (4), and R ₂₁ and R ₂₂ are both the same group and are an alkyl group or an aryl group:

In formula (4), _Rx1 and _Rx2 each independently represent an alkyl group, _Rx3 represents a hydrogen atom or an alkyl group, two or more of _Rx1 to _Rx3 may be bonded to each other to form a ring, and * represents a linking portion to a carbon atom in the ester structure.
<5> The curable composition according to any one of <1> to <4>, wherein X in formula (1) represents any one of the following (X-1) to (X-14):

In (X-1) to (X-14), R ^X1 to R ^X9 each independently represent a hydrogen atom, an alkyl group or an aryl group, L represents a divalent linking group, and * represents a linking portion to a (keto)oxime group.
<6> The curable composition according to any one of <1> to <5>, further comprising a colorant.
<7> The curable composition according to any one of <1> to <6>, further comprising a polyfunctional thiol compound.
<8> The curable composition according to any one of <1> to <7>, in which the resin having a crosslinkable group and a graft chain is an acrylic resin.
<9> The curable composition according to any one of <1> to <8>, wherein the resin having a crosslinkable group and a graft chain has at least one group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group.
<10> The curable composition according to any one of <1> to <9>, wherein the crosslinkable group is at least one group selected from the group consisting of an ethylenically unsaturated group and a cyclic ether group.
<11> The curable composition according to any one of <1> to <10>, in which a content of the radical curable compound having a molecular weight of less than 3,000 is less than 15 mass% based on a total solid content of the radical curable compound.
<12> The curable composition according to <11>, in which a mass ratio W _C1 /W _A is less than 5, where W _C1 is the content of the radical curable compound having a molecular weight of less than 3,000 and W _A is the content of the radical polymerization initiator represented by formula (1).
<13> The curable composition according to any one of <1> to <12>, which is for exposure to an excimer laser having a wavelength of 150 nm to 300 nm.
<14> A method for producing a cured product, comprising a step of irradiating the curable composition according to any one of <1> to <13> with excimer laser light having a wavelength of 150 nm to 300 nm.
<15> A film obtained by curing the curable composition according to any one of <1> to <13>.
<16> An optical element comprising the film according to <15>.
<17> An image sensor comprising the film according to <15>.
<18> A solid-state imaging device comprising the film according to <15>.
<19> An image display device comprising the film according to <15>.
<20> A radical polymerization initiator represented by formula (3):

In formula (3), X represents a divalent organic group, _R21 and _R22 each independently represent a monovalent organic group, or a divalent organic group linked to X, _Rx1 and _Rx2 each independently represent an alkyl group, _Rx3 each independently represent a hydrogen atom or an alkyl group, two or more of _Rx1 to _Rx3 may be bonded to each other to form a ring, and n1 and n2 each independently represent 0 or 1.

According to one embodiment of the present disclosure, there is provided a curable composition which has high sensitivity and excellent cross-sectional rectangularity when patterned.
According to other embodiments of the present disclosure, there are provided a method for producing a cured product using the curable composition, a film, an optical element, an image sensor, a solid-state imaging element, and an image display device.
Furthermore, according to another embodiment of the present disclosure, a novel radical polymerization initiator is provided.

The contents of this disclosure are described in detail below. The components described below may be explained based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments.

In this disclosure, a numerical range indicated using "~" indicates a range that includes the numerical value described before "~" as the lower limit and the numerical value described before "~" as the upper limit. In the numerical ranges described in stages in this disclosure, the upper or lower limit described in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages. In addition, in the numerical ranges described in this disclosure, the upper or lower limit described in a certain numerical range may be replaced with a value shown in the examples.

In this specification, when a group (atomic group) is represented, a notation that does not indicate whether it is substituted or unsubstituted includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have a substituent. For example, an "alkyl group" includes not only an alkyl group that has no substituents (unsubstituted alkyl groups), but also an alkyl group that has a substituent (substituted alkyl groups).

In this specification, unless otherwise specified, "exposure" includes not only exposure using light, but also drawing using particle beams such as electron beams and ion beams. Examples of light used for exposure include the bright line spectrum of a mercury lamp, far ultraviolet light as represented by an excimer laser, extreme ultraviolet light (EUV light), X-rays, active rays or radiation such as electron beams, etc.

In this specification, "(meth)acrylate" refers to both or either of acrylate and methacrylate, "(meth)acrylic" refers to both or either of acrylic and methacrylic, and "(meth)acryloyl" refers to both or either of acryloyl and methacryloyl.
In this specification, in the structural formulae, Me represents a methyl group, Et represents an ethyl group, Bu represents a butyl group, and Ph represents a phenyl group.

In this specification, the weight average molecular weight and number average molecular weight are values calculated in terms of polystyrene measured by GPC (gel permeation chromatography).
The measurement by GPC uses an HLC (registered trademark)-8020GPC (Tosoh Corporation) as a measuring device, three TSKgel (registered trademark) Super Multipore HZ-H (4.6 mm ID x 15 cm, Tosoh Corporation) as columns, and THF (tetrahydrofuran) as an eluent. The measurement conditions are a sample concentration of 0.45 mass%, a flow rate of 0.35 ml/min, a sample injection amount of 10 μl, and a measurement temperature of 40 ° C., and is performed using an RI detector. The calibration curve is prepared from eight samples of "Standard sample TSK standard, polystyrene" from Tosoh Corporation: "F-40", "F-20", "F-4", "F-1", "A-5000", "A-2500", "A-1000", and "n-propylbenzene".

In this specification, the total solids content refers to the total mass of all components of the composition excluding the solvent.
In this specification, a pigment means a coloring material that is difficult to dissolve in a solvent.
In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the process achieves its intended effect.
In the present specification, for oxime compounds having E- and Z-stereoisomers, unless otherwise specified, either the E- or Z-isomer may be used.
The present disclosure will be described in detail below.

(Curable Composition)
The curable composition of the present disclosure includes a radical polymerization initiator represented by formula (1), a radical curable compound, and a resin having a crosslinkable group and a graft chain. The curable composition of the present disclosure preferably includes a coloring material, and may further include other components as necessary.

The curable composition of the present disclosure has high sensitivity and excellent pattern formability, and in particular, the cross-sectional rectangularity of the formed pattern is excellent. The reason why such effects are exhibited is not necessarily clear, but is presumed to be as follows.
The radical polymerization initiator represented by formula (1) has a di(keto)oxime structure, which promotes the generation of radical polymerization initiating species, and further contains a resin having a crosslinkable group and a graft chain, which allows the radical polymerization initiating species generated from the radical polymerization initiator to be efficiently diffused, and the polymerization reaction proceeds well over a wide area of the pattern portion to be formed. As a result, the curable composition has high sensitivity, and the curability up to the bottom of the pattern is also improved.
The above-mentioned Patent Documents 1 and 2 do not have compositions containing a dimer-type radical polymerization initiator having a bulky structure at a (keto)oxime moiety and a resin having a crosslinkable group and a graft chain. Therefore, the polymerization initiator is hydrolyzed over time, making it difficult to suppress the desensitization phenomenon in which the curing sensitivity decreases over time.

The curable composition according to the present disclosure can be suitably used as a photocurable composition, more suitably used as a curable composition for exposure to light having a wavelength of 150 nm to 300 nm, and particularly suitably used as a curable composition for exposure to an excimer laser having a wavelength of 150 nm to 300 nm.

The curable composition according to the present disclosure is preferably used as a curable composition for optical filters. Examples of optical filters include color filters and infrared transmission filters, and color filters are preferred. That is, the curable composition according to the present disclosure is preferably used as a curable composition for color filters. More specifically, it can be preferably used as a curable composition for forming pixels of a color filter. Examples of types of pixels include red pixels, green pixels, blue pixels, magenta pixels, cyan pixels, and yellow pixels.

Preferred examples of the infrared transmission filter include filters that satisfy the spectral characteristics of a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 640 nm and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 1,100 nm to 1,300 nm. The infrared transmission filter is preferably a filter that satisfies any of the following spectral characteristics (1) to (5).
(1): A filter having a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 640 nm, and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 800 nm to 1,500 nm.
(2): A filter having a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 750 nm, and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 900 nm to 1,500 nm.
(3): A filter having a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 830 nm, and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 1,000 nm to 1,500 nm.
(4): A filter having a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 950 nm, and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 1,100 nm to 1,500 nm.
(5): A filter having a maximum transmittance of 20% or less (preferably 15% or less, more preferably 10% or less) in the wavelength range of 400 nm to 1,050 nm, and a minimum transmittance of 70% or more (preferably 75% or more, more preferably 80% or more) in the wavelength range of 1,200 nm to 1,500 nm.

The curable composition according to the present disclosure is preferably used for solid-state imaging devices. More specifically, it is preferably used as a curable composition for optical filters used in solid-state imaging devices, and is more preferably used as a curable composition for color filters used in solid-state imaging devices.

The solids concentration of the curable composition according to the present disclosure is preferably 5% by mass to 40% by mass. The lower limit is more preferably 7.5% by mass or more, and even more preferably 10% by mass or more. The upper limit is more preferably 35% by mass or less, and even more preferably 30% by mass or less.

The components contained in the curable composition according to this disclosure are described below.

<Radical Polymerization Initiator Represented by Formula (1)>
The curable composition of the present disclosure contains a radical polymerization initiator (A) represented by the following formula (1).

X represents a divalent organic group and can serve as an absorbing nucleus.
Examples of the divalent organic group in X include an aromatic ring group, a group having two or more aromatic rings, and a condensed ring of two or more aromatic rings, and are preferably a 6-membered aromatic ring group, a group having two or more 6-membered aromatic rings, and a condensed ring of a 6-membered aromatic ring and a 5-membered aromatic ring, and more preferably a condensed ring of a 3-ring, and a condensed ring of a 6-membered aromatic ring and a 5-membered aromatic ring. Suitable examples of the divalent organic group in X include the following (X-1) to (X-18).

In (X-1) to (X-18), R ^X1 to R ^X9 each independently represent a hydrogen atom, an alkyl group or an aryl group, L represents a divalent linking group, and * represents a linking portion to a (keto)oxime group.

The alkyl group in R ^X1 to R ^X9 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.
The aryl group in R ^X1 to R ^X9 is preferably an aryl group having 6 to 12 carbon atoms, and examples thereof include a phenyl group and a naphthyl group.
The divalent linking group for L includes an alkylene group having 1 to 4 carbon atoms, such as a methylene group and an ethylene group.

Among the above, it is preferable that X represents any one of (X-1) to (X-14). From the viewpoint of sensitivity, it is more preferable that X represents (X-1), (X-2), (X-3), (X-4), (X-6) or (X-8), and a divalent three-ring condensed ring group is even more preferable, it is particularly preferable that (X-2), (X-4), (X-6) or (X-8), and it is most preferable that (X-2), (X-4) or (X-6) is.

R ₁₁ and R ₁₂ each independently represent an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group. Among them, from the viewpoint of obtaining a bulky structure and improving both sensitivity and hydrolysis resistance, R ₁₁ and R ₁₂ are preferably groups having 3 or more carbon atoms, and more preferably groups having 3 to 12 carbon atoms. Furthermore, from the viewpoint of further increasing sensitivity while improving hydrolysis resistance, it is even more preferable that they are alkyl groups having 4 to 6 carbon atoms.
Moreover, R ₁₁ and R ₁₂ are each preferably independently an alkyl group or an aryl group having a linear, branched or cyclic structure, and from the viewpoint of enhancing both sensitivity and hydrolysis resistance, are further preferably a branched alkyl group or an alicyclic alkyl group.

In addition, when R ₁₁ and R ₁₂ each represent an alkyl group, from the viewpoint of achieving both sensitivity and hydrolysis resistance, a secondary alkyl group or a tertiary alkyl group is preferable to a primary alkyl group, and a tertiary alkyl group is more preferable. As the alkyl group in R ₁₁ and R ₁₂ , for example, any one of an isopropyl group, a t-butyl group, a t-amyl group, an isoamyl group, a neopentyl group, a sec-butyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 1-methyl-1-cyclopropyl group, a 1-methyl-1-cyclobutyl group, a 1-methyl-1-cyclopentyl group, a 1-methyl-1-cyclohexyl group, and a 1-adamantyl group is preferable, and a t-butyl group is most preferable.

The aryl group for R ₁₁ and R ₁₂ is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms.
The heteroaryl group for R ₁₁ and R ₁₂ is preferably a heteroaryl group having 4 to 20 carbon atoms, and more preferably a heteroaryl group having 4 to 10 carbon atoms.
The alkoxy group for R ₁₁ and R ₁₂ is preferably an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkoxy group having 1 to 4 carbon atoms.
The aryloxy group for R ₁₁ and R ₁₂ is preferably an aryloxy group having 6 to 20 carbon atoms, and more preferably an aryloxy group having 6 to 12 carbon atoms.
The heteroaryloxy group for R ₁₁ and R ₁₂ is preferably a heteroaryloxy group having 4 to 20 carbon atoms, and more preferably a heteroaryloxy group having 4 to 10 carbon atoms.
Each of the groups represented by R ₁₁ and R ₁₂ may further have a substituent.

From the viewpoint of enhancing both sensitivity and hydrolysis resistance, R ₁₁ and R ₁₂ are preferably the same group, and more preferably R ₁₁ and R ₁₂ are the same group and are a group represented by the following formula (4).

In formula (4), _Rx1 and _Rx2 each independently represent an alkyl group, _Rx3 represents a hydrogen atom or an alkyl group, two or more of _Rx1 to _Rx3 may be bonded to each other to form a ring, and * represents a linking portion to a carbon atom in the ester structure.

The alkyl group in _Rx1 and _Rx2 is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group, with a methyl group and an ethyl group being preferred.
The alkyl group for _Rx3 is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group, with a methyl group being preferred.

Specific examples of groups represented by _R11 and _R12 are shown below. However, the examples are not limited to these. In addition, "*" in each group indicates a bond.

As R ₁₁ and R ₁₂ , (R-4) to (R-14) are preferable, (R-6), (R-7), (R-12), (R-13) and (R-14) are more preferable, and (R-6) is the most preferable.

As the radical polymerization initiator represented by formula (1), it is particularly preferred that X is (X-2), (X-4), (X-6) or (X-8), and R ₁₁ and R ₁₂ are (R-6), (R-7), (R-12), (R-13) or (R-14), and it is most preferred that X is (X-2), (X-4) or (X-6), and R ₁₁ and R ₁₂ are (R-6).

R ₂₁ and R ₂₂ each independently represent a monovalent organic group, or a divalent organic group linked to X. From the viewpoint of sensitivity, R ₂₁ and R ₂₂ are preferably the same group.

From the viewpoint of sensitivity, the monovalent organic group in R ₂₁ and R ₂₂ is preferably an unsubstituted alkyl group having a linear, branched or cyclic structure, an aryl group, or an alkyl group having at least one substituent selected from the following Group A, more preferably a methyl group or an alkyl group having at least one substituent selected from the following Group A, even more preferably an alkyl group having at least one substituent selected from the following Group A, particularly preferably an alkyl group having at least one substituent selected from the following Group B, and most preferably an alkyl group having at least one substituent selected from the following Group C.

- Group A -
Cyano group, alkenyl group, alkynyl group, -N(R _a ) ₂ , -SR _a , -COOH, -OR _a , -O-COR _c , -O-CO-OR _c , -CONR _a R _b , -NR _a -CO-R _b , -O-CO-NR _a R _b , -NR _a -CO-OR _b , -NR _a -CO-NR _a R _b , -SO-R _c , -SO ₂ -R _c , -O-SO ₂ -R _c , -SO ₂ -NR _a R _b , -NR _a -SO ₂ -R _a , -CO-NR _a -COR _b , -CO-NR _a -SO ₂ -R _b , -SO ₂ -NR _a -CO-R _b , -SO ₂ -NR _a -SO ₂ -R _c , -Si(R _a ) _L (OR _b ) _K , a heterocyclic group, and -O(R _d O) _J -R _a
Here, R _a and R _b each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group; R _c represents an alkyl group, an aryl group, or a heteroaryl group; R _d each independently represent an alkylene group, an arylene group, or a group combining two or more of these; L and K each independently represent an integer of 0 to 3, satisfying L+K=3; and J represents an integer of 1 to 100.
- Group B -
Alkenyl groups, -N(R _a ) ₂ , -SR _a , -OR _a
- Group C -
-N(R _a ) ₂ , -SR _a , -OR _a

Here, each R _a independently represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group. Each _{R a} independently represents an alkyl group, an aryl group, or a heteroaryl group, more preferably an alkyl group, and particularly preferably a cycloalkyl group.
Each R _b is preferably a hydrogen atom or an alkyl group, and more preferably an alkyl group.
R _c is preferably an alkyl group or an aryl group, and is preferably an alkyl group.
Each _Rd is preferably an alkylene group, and more preferably an ethylene group or a propylene group.
Two or more of the above R _a to R _c may be bonded to form a ring structure.

As the monovalent organic group for R ₂₁ and R ₂₂ , a group represented by the following formula (2) is preferable.

In formula (2), _R2 represents an alkyl group, provided that when _L2 is CHR, _R2 may be a hydrogen atom, _R3 represents a hydrogen atom or an alkyl group, _R4 represents an alkyl group, _L1 and _L2 each independently represent CHR, O, S or NR, R each independently represent a hydrogen atom or an alkyl group, two or more of _R2 , _R3 , _R4 and R may be bonded to each other to form a ring structure, Z represents a single bond or an alkylene group having 1 to 6 carbon atoms, and * represents a linking portion with the oxime group.

From the viewpoint of sensitivity, _R2 in formula (2) is preferably an alkyl group.
From the viewpoint of sensitivity, R ₃ in formula (2) is preferably a hydrogen atom.
From the viewpoint of sensitivity, R ₄ in formula (2) is preferably an alkyl group having 1 to 6 carbon atoms.
Among these, from the viewpoints of compatibility with the radical polymerizable compound and sensitivity, it is preferable that _R2 and _R4 are bonded to each other to form a ring structure, and it is more preferable that _R2 and _R4 are bonded to each other to form an aliphatic hydrocarbon ring structure.
In terms of sensitivity, L ₁ in formula (2) is preferably O, S or NR, and more preferably O or NR.
In terms of sensitivity, _L2 in formula (2) is preferably CHR.
From the viewpoint of sensitivity, R in the above NR is preferably an alkyl group, more preferably a methyl group or a cycloalkyl group, and particularly preferably a methyl group, a cyclopentyl group, or a cyclohexyl group.
From the viewpoint of sensitivity, R in the above CHR is preferably a hydrogen atom.
In terms of sensitivity, Z in formula (2) is preferably a single bond or an alkylene group having 1 to 4 carbon atoms, more preferably a single bond, a methylene group or an ethylene group, and particularly preferably a single bond.

From the viewpoint of sensitivity, R ₂₁ and R ₂₂ in formula (1) are more preferably groups represented by the following formula (2-1).

In formula (2-1), _R3 represents a hydrogen atom or an alkyl group, _L1 and _L2 each independently represent CHR, O, S, or NR, _L1 represents an alkylene group having 1 to 6 carbon atoms, R each independently represents a hydrogen atom or an alkyl group, Z represents a single bond or an alkylene group having 1 to 6 carbon atoms, and * represents a linking portion to the oxime group.

Preferred embodiments of R ₃ , L ₁ , L ₂ , R and Z in formula (2-1) are the same as the preferred embodiments of R ₃ , L ₁ , L ₂ , R and Z in formula (2), respectively.
In terms of sensitivity, L 3 _A in formula (2-1) is preferably an alkylene group having 3 or 4 carbon atoms, and more preferably a 1,3-propylene group.

From the viewpoint of sensitivity, R ₂₁ and R ₂₂ in formula (1) are more preferably a group represented by the following formula (3).

In formula (3), _L3 and _L4 each independently represent CHR, O, S, or NR, at least one of _L3 and _L4 is CHR, R represents a hydrogen atom or an alkyl group, _R5 each independently represents a hydrogen atom or an alkyl group, p represents an integer of 1 to 6, and * represents a linking portion to the (keto)oxime group.

In terms of sensitivity, _L3 in formula (3) is preferably O, S or NR.
In terms of sensitivity, _L4 in formula (3) is preferably CHR.
The preferred embodiments of R in formula (3) are the same as the preferred embodiments of R in formula (2).
From the viewpoint of sensitivity, R ₅ in formula (3) is preferably a hydrogen atom.
In the formula (3), p is preferably an integer of 3 to 5, more preferably 3 or 4, and particularly preferably 3, from the viewpoint of sensitivity.

Specific examples of the groups represented by R ₂₁ and R ₂₂ are shown below. In addition, "*" indicates the bonding position with the (keto)oxime group.

From the viewpoint of sensitivity, it is preferable that the group is at least one group selected from the group consisting of Y-1, Y-2, Y-3, Y-12, Y-13, Y-14, Y-15, Y-16, Y-17, and Y-18, and it is more preferable that the group is at least one group selected from the group consisting of Y-2, Y-13, Y-14, Y-15, Y-16, Y-17, and Y-18.

In formula (1), furthermore, from the viewpoint of improving sensitivity and hydrolysis resistance, it is preferable that R ₁₁ and R ₁₂ are both the same group.

n1 and n2 each independently represent 0 or 1.

The radical polymerization initiator represented by formula (1) has an oxime group or a ketoxime group.
The oxime group or ketoxime group is a group represented by the following formula (A1) or (A2). That is, the oxime group or ketoxime group may be the geometric isomer E (A1) or the geometric isomer Z (A2). The radical polymerization initiator represented by formula (1) may be a mixture of an oxime group or ketoxime group in the geometric isomer E (A1) and an oxime group in the geometric isomer Z (A2).

In formula (A1) and formula (A2), R _1a has the same meaning as R ₁₁ and R ₁₂ in formula (1), and R _2a has the same meaning as R ₂₁ and R ₂₂ in formula (1). n represents 0 or 1, and "*" represents a bond to X in formula (1). The groups represented by formula (A1) and formula (A2) are oxime groups when n is 0, and are ketoxime groups when n is 1. In the present disclosure, a ketoxime group is preferred in terms of sensitivity and hydrolysis resistance.

When the radical polymerization initiator represented by formula (1) contains multiple oximes in one molecule, the E isomer and the Z isomer may be mixed. When the radical polymerization initiator represented by formula (1) contains E and Z isomers, the ratio of E to Z isomers (E/Z) is preferably 100/0 to 1/99, more preferably 100/0 to 50/50, even more preferably 100/0 to 80/20, and particularly preferably 100/0 to 90/10.

When the curable composition of the present disclosure contains a dispersant and the dispersant has an amino group such as polyethyleneimine, hydrolysis of the polymerization initiator in the curable composition is likely to be accelerated. The curable composition of the present disclosure contains a radical polymerization initiator represented by formula (1) as the initiator component, so that the hydrolysis reaction that is likely to occur due to the amino group can be suppressed. This results in excellent storage stability.

The molecular weight of the radical polymerization initiator represented by formula (1) is preferably low in terms of sensitivity, more preferably 200 to 2000, even more preferably 300 to 1000, and particularly preferably 400 to 900.

The radical polymerization initiator represented by formula (1) preferably has absorption in KrF light (wavelength 248 nm) and i-line (wavelength 365 nm). The molar absorption coefficient at a wavelength of 248 nm is preferably 5000 or more, more preferably 10000 or more, even more preferably 20000 or more, and particularly preferably 30000 or more. The upper limit of the molar absorption coefficient at a wavelength of 248 nm is not particularly limited, but is generally less than 200000. The molar absorption coefficient at a wavelength of 365 nm is preferably 5000 or more, more preferably 10000 or more, even more preferably 20000 or more, and particularly preferably 30000 or more. The upper limit of the molar absorption coefficient at a wavelength of 365 nm is not particularly limited, but is generally less than 200000. High absorption leads to good sensitivity and pattern rectangularity.
The long wavelength end of absorption (the longest wavelength at which the molar absorption coefficient is less than 100) is preferably 500 nm or less, more preferably 450 nm or less, and even more preferably 420 nm or less. The above wavelength range prevents yellow light fogging, provides excellent light stability during synthesis, and the polymerization initiator does not exhibit yellow color, resulting in good color reproducibility of a colored pattern (for example, a color filter having colored pixels).

The radical polymerization initiator represented by formula (1) may be partially hydrolyzed and mixed in in the form of an oxime. From the viewpoint of sensitivity, the amount of hydrolyzed radical polymerization initiator is preferably less than 1 part by mass, and more preferably less than 0.5 parts by mass, per 100 parts by mass of the radical polymerization initiator represented by formula (1). There is no lower limit to the amount, but it is generally less than 0.001 parts by mass.

If part of the radical polymerization initiator represented by formula (1) is hydrolyzed and mixed in the form of an oxime, the carboxylic acid that formed an ester with the oxime is likely to be liberated. From the viewpoint of sensitivity, the amount of free carboxylic acid is preferably less than 1 part by mass, and more preferably less than 0.5 parts by mass, per 100 parts by mass of the radical polymerization initiator represented by formula (1). There is no lower limit to the above amount, but it is generally less than 0.001 parts by mass.

Specific examples of the radical polymerization initiator represented by formula (1) are shown below. However, the examples are not limited thereto. In addition, X, R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , n1 and n2 in the specific examples in the table below are the same as X, R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , n1 and n2 in general formula (1), respectively.

The curable composition according to the present disclosure may contain one radical polymerization initiator represented by formula (1) alone or two or more radical polymerization initiators. When two or more radical polymerization initiators are contained, the total amount is preferably within the following range.
The content of the radical polymerization initiator represented by formula (1) is, from the viewpoint of sensitivity, preferably 0.01 mass % to 20 mass %, more preferably 0.05 mass % to 15 mass %, still more preferably 0.1 mass % to 10 mass %, and particularly preferably 0.1 mass % to 5 mass %, based on the total solid content of the curable composition.

<Other radical polymerization initiators>
The curable composition of the present disclosure may contain a radical photopolymerization initiator (hereinafter also simply referred to as a photopolymerization initiator) other than the radical polymerization initiator represented by formula (1).
The photopolymerization initiator is not particularly limited and can be appropriately selected from known photopolymerization initiators. For example, a compound having photosensitivity to light in the ultraviolet to visible range is preferred. The photopolymerization initiator is preferably a photoradical polymerization initiator.

Examples of the photopolymerization initiator include halogenated hydrocarbon derivatives (e.g., compounds having a triazine skeleton, compounds having an oxadiazole skeleton, etc.), acylphosphine compounds, hexaarylbiimidazole compounds, oxime compounds, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, α-hydroxyketone compounds, α-aminoketone compounds, etc. From the viewpoint of exposure sensitivity, the photopolymerization initiator is preferably a trihalomethyltriazine compound, a benzyldimethylketal compound, an α-hydroxyketone compound, an α-aminoketone compound, an acylphosphine compound, a phosphine oxide compound, a metallocene compound, an oxime compound, a hexaarylbiimidazole compound, an onium compound, a benzothiazole compound, a benzophenone compound, an acetophenone compound, a cyclopentadiene-benzene-iron complex, a halomethyloxadiazole compound, or a 3-aryl substituted coumarin compound, more preferably a compound selected from an oxime compound, an α-hydroxyketone compound, an α-aminoketone compound, or an acylphosphine compound, and even more preferably an oxime compound. Examples of the photopolymerization initiator include the compounds described in paragraphs 0065 to 0111 of JP 2014-130173 A, the compounds described in Japanese Patent No. 6301489 A, the peroxide-based photopolymerization initiators described in MATERIAL STAGE 37 to 60p, vol. 19, No. 3, 2019, the photopolymerization initiators described in WO 2018/221177 A, the photopolymerization initiators described in WO 2018/110179 A, the photopolymerization initiators described in JP 2019-043864 A, and the photopolymerization initiators described in JP 201
Photopolymerization initiators described in JP-A-9-044030, peroxide-based initiators described in JP-A-2019-167313, aminoacetophenone-based initiators having an oxazolidine group described in JP-A-2020-055992, oxime-based photopolymerization initiators described in JP-A-2013-190459, polymers described in JP-A-2020-172619, compounds represented by formula 1 described in WO 2020/152120, compounds described in JP-A-2021-181406, photopolymerization initiators described in JP-A-2022-013379, and described in JP-A-2022-015747 Compounds represented by the formula (1), fluorine-containing fluorene oxime ester photoinitiators described in JP-T-2021-507058, initiators described in China Patent Application Publication No. 110764367, initiators described in JP-T-2022-518535, initiators described in WO 2021/175855, compounds described in Taiwan Patent Application Publication No. 202200534, compounds described in JP-A-2022-078550, compounds described in Korean Patent Publication No. 10-2017-0087330, compounds described in WO 2022/075452, and the like.

Specific examples of hexaarylbiimidazole compounds include 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4,5-diphenyl-1,1'-biimidazole.

Commercially available α-hydroxyketone compounds include Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127 (all manufactured by IGM Resins B.V.), Irgacure 184, Irgacure 1173, Irgacure 2959, Irgacure 127 (all manufactured by BASF), etc. Commercially available α-aminoketone compounds include Omnirad 907, Omnirad 369, Omnirad 369E, Omnirad 379EG (all manufactured by IGM Resins B.V.), Irgacure 907, Irgacure 369, Irgacure 369E, Irgacure 379EG (all manufactured by BASF), etc. Commercially available acylphosphine compounds include Omnirad 819, Omnirad TPO (all manufactured by IGM Resins B.V.), Irgacure 819, Irgacure TPO (all manufactured by BASF), etc.

Examples of the oxime compound include the compounds described in paragraph 0142 of WO 2022/085485, the compounds described in Japanese Patent No. 5,430,746, the compounds described in Japanese Patent No. 5,647,738, the compounds represented by the general formula (1) of JP-A-2021-173858, the compounds described in paragraphs 0022 to 0024, the compounds represented by the general formula (1) of JP-A-2021-170089, and the compounds described in paragraphs 0117 to 0120. Specific examples of the oxime compound include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentan-3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-(4-toluenesulfonyloxy)iminobutan-2-one, 2-ethoxycarbonyloxyimino-1-phenylpropan-1-one, 1-[4-(phenylthio)phenyl]-3-cyclohexyl-propane-1,2-dione-2-(O-acetyloxime), and the like. Commercially available products include Irgacure OXE01, Irgacure OXE02, Irgacure OXE03, and Irgacure OXE04 (manufactured by BASF), TR-PBG-301, TR-PBG-304, and TR-PBG-327 (manufactured by TRONLY), and ADEKA OPTOMER N-1919 (manufactured by ADEKA Corporation, photopolymerization initiator 2 described in JP-A-2012-014052). In addition, as the oxime compound, it is also preferable to use a compound that is not colorable or a compound that is highly transparent and does not easily discolor. Commercially available products include ADEKA ARCLES NCI-730, NCI-831, and NCI-930.
(All of the above are manufactured by ADEKA Corporation).

As the photopolymerization initiator, an oxime compound having a fluorene ring, an oxime compound having a skeleton in which at least one benzene ring of a carbazole ring is replaced with a naphthalene ring, an oxime compound having a fluorine atom, an oxime compound having a nitro group, an oxime compound having a benzofuran skeleton, an oxime compound in which a substituent having a hydroxyl group is bonded to a carbazole skeleton, or a compound described in paragraphs 0143 to 0149 of WO 2022/085485 can be used.

As the photopolymerization initiator, a compound represented by formula (OX-1) can also be used. According to this embodiment, the sensitivity of the curable composition can be further increased.

In formula (OX-1), X ^1a represents a divalent linking group containing at least one ring selected from the group consisting of an aromatic ring and a heterocycle;
R ^1a represents a hydrogen atom or an acyl group;
^R2a represents an alkyl group or an aryl group;
R ^3a and R ^4a each independently represent a hydrogen atom or an alkyl group;
Alk ¹ and Alk ² each independently represent an alkyl group;
R ^3a and R ^4a may be bonded to form a ring;
Alk ¹ and Alk ² may be linked to form a ring;
n represents 0 or 1.

Examples of the divalent linking group represented by X ^1a in formula (OX-1) include a divalent aromatic ring group, a divalent heterocyclic group, a divalent group in which two or more aromatic rings are bonded via a single bond or a linking group, a divalent group in which two or more heterocycles are bonded via a single bond or a linking group, and a divalent group in which an aromatic ring and a heterocycle are bonded via a single bond or a linking group. Examples of the linking group include -CH ₂ -, -O-, -CO-, -S-, -NR ^x -, and groups combining these. R ^x represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group.

X ^1a in formula (OX-1) is preferably a group represented by any one of formulas (X-1) to (X-13), more preferably a group represented by formula (X-1), formula (X-2), formula (X-4), formula (X-6) or formula (X-8), and further preferably a group represented by formula (X-2) or formula (X-6).

In the formula, R ^X1 to R ^X9 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group. * represents a linking portion.

The number of carbon atoms in the alkyl group represented by R ^X1 to R ^X9 is preferably 1 to 15, and more preferably 1 to 10. The alkyl group may be linear, branched, or cyclic. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an aryl group, and a heterocyclic group.

The number of carbon atoms in the alkenyl group represented by R ^X1 to R ^X9 is preferably 2 to 15, and more preferably 2 to 10. The alkenyl group may be linear, branched, or cyclic. The alkenyl group may have a substituent. Examples of the substituent include a halogen atom, an aryl group, and a heterocyclic group.

The number of carbon atoms in the alkynyl group represented by R ^X1 to R ^X9 is preferably 2 to 15, and more preferably 2 to 10. The alkynyl group may be linear, branched, or cyclic. The alkynyl group may have a substituent. Examples of the substituent include a halogen atom, an aryl group, and a heterocyclic group.

The number of carbon atoms in the aryl group represented by R ^X1 to R ^X9 is preferably 6 to 20, more preferably 6 to 12, still more preferably 6 to 10, and particularly preferably 6. The aryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, and a heterocyclic group.

The heterocyclic group represented by R ^X1 to R ^X9 is preferably a 5-membered or 6-membered ring. The heteroatoms contained in the heterocyclic group are preferably an oxygen atom, a nitrogen atom, or a sulfur atom. The number of heteroatoms contained in the heterocyclic group is preferably 1 to 3. The heterocyclic group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, and an aryl group.

In formula (OX-1), R ^1a represents a hydrogen atom or an acyl group, and is preferably an acyl group.
The acyl group represented by R ^1a is preferably a group represented by —C(O)—R ^101. R ¹⁰¹ represents an aryl group or a heterocyclic group, and is preferably an aryl group.

The number of carbon atoms of the aryl group represented by R ¹⁰¹ is preferably 6 to 20, and more preferably 6 to 12. The aryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an arylamino group, and an acyl group. The aryl group represented by R ¹⁰¹ is preferably a phenyl group, a methylphenyl group, or a naphthyl group, and more preferably a methylphenyl group or a naphthyl group.

The heterocyclic group represented by R ¹⁰¹ is preferably a 5-membered or 6-membered ring. The heteroatoms contained in the heterocyclic group are preferably an oxygen atom, a nitrogen atom, or a sulfur atom. The number of heteroatoms contained in the heterocyclic group is preferably 1 to 3. The heterocyclic group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an alkylthio group, an alkylamino group, an aryloxy group, an arylthio group, an arylamino group, and an acyl group.

R ^2a in formula (OX-1) represents an alkyl group or an aryl group, and is preferably an alkyl group because the reactivity of the generated radical is high.
The number of carbon atoms of the alkyl group represented by R ^2a is preferably 1 to 15, more preferably 1 to 10, even more preferably 1 to 5, and even more preferably 1 to 3. The alkyl group may be linear, branched, or cyclic, but is preferably linear or branched, and more preferably linear. The alkyl group may have a substituent, but is preferably an unsubstituted alkyl group. The alkyl group represented by R ^2a is preferably an unsubstituted linear or branched alkyl group, and more preferably an unsubstituted linear alkyl group.
The number of carbon atoms in the aryl group represented by R ^2a is preferably 6 to 20, more preferably 6 to 12, still more preferably 6 to 10, and particularly preferably 6. The aryl group may have a substituent, but is preferably an unsubstituted aryl group.

In formula (OX-1), R ^3a and R ^4a each independently represent a hydrogen atom or an alkyl group, and preferably a hydrogen atom.
The number of carbon atoms in the alkyl group represented by R ^3a and R ^4a is preferably 1 to 15, more preferably 1 to 10, even more preferably 1 to 5, and even more preferably 1 to 3. The alkyl group may be linear, branched, or cyclic, but is preferably linear or branched, and more preferably linear. The alkyl group may have a substituent, but is preferably an unsubstituted alkyl group.
^R3a and ^R4a may be bonded to form a ring. The ring formed is preferably a 5- or 6-membered ring, and more preferably a 5- or 6-membered aliphatic hydrocarbon ring.

In formula (OX-1), Alk ¹ and Alk ² each independently represent an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 15, more preferably 1 to 10, even more preferably 1 to 5, and even more preferably 1 to 3. The alkyl group may be linear, branched, or cyclic, but is preferably linear or branched, and more preferably linear. The alkyl group may have a substituent, but is preferably an unsubstituted alkyl group.
^Alk1 and ^Alk2 may be bonded to form a ring, and preferably form a ring. The ring formed is preferably a 5- or 6-membered ring, more preferably a 5- or 6-membered aliphatic hydrocarbon ring, and more preferably a cyclopentane ring or a cyclohexane ring.

In formula (OX-1), n represents 0 or 1, and is preferably 0.

Specific examples of the compound represented by formula (OX-1) include the compounds described in paragraphs 0092 to 0096 of JP2012-113104A and the compounds described in paragraph 0041 of JP2012-189997A.

As the photopolymerization initiator, a compound represented by formula (OX-2) can also be used. According to this embodiment, the sensitivity of the curable composition can be further increased.

In formula (OX-2), R ^1b and R ^2b each independently represent a substituent, R ^3b to R ^7b each independently represent a hydrogen atom or a substituent, Ar ^1b represents an aromatic ring group which may have a substituent or a heterocyclic group which may have a substituent, and n represents 0 or 1.

Suitable examples of the substituent represented by R ^1b and R ^2b include an alkyl group and an aryl group, and an alkyl group is preferable. The number of carbon atoms in the alkyl group is preferably 1 to 15, and more preferably 1 to 10. The alkyl group may be linear, branched, or cyclic. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an aryl group, an alkenyl group, an alkynyl group, and a heterocyclic group. The number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 12, even more preferably 6 to 10, and particularly preferably 6. The aryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, and a heterocyclic group.

Suitable examples of the substituents represented by R ^3b to R ^7b include a halogen atom, an alkyl group and an aryl group. The alkyl group and aryl group have the same meaning as the alkyl group and aryl group in the substituents represented by R ^1b and R ^2b .
R ^3b to R ^7b are preferably hydrogen atoms.

Ar ^1b represents an aromatic ring group which may have a substituent or a heterocyclic group which may have a substituent, and Ar ^1b is preferably an aromatic ring group which may have a substituent. The aromatic ring group is preferably a benzene ring group or a naphthalene ring group, and more preferably a benzene ring group. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, and an acyl group, and an acyl group is preferable. The acyl group has the same meaning as the acyl group in R ^1a of formula (OX-1).

As the photopolymerization initiator, a compound represented by formula (OX-3) can also be used. According to this embodiment, the sensitivity of the curable composition can be further increased.

In formula (OX-3), Ar ^1c represents a (k+m+1)-valent aromatic ring group or a (k+m+1)-valent heterocyclic group;
Ar ^2c represents a (k+2)-valent aromatic ring group or a (k+2)-valent heterocyclic group;
R ^1c to R ^3c each independently represent a substituent;
L ^1c represents a single bond or CR ^11c R ^12c , and R ^11c and R ^12c each independently represent a hydrogen atom, an alkyl group, or an aryl group;
X ^1c represents -C-, -N-, -O- or -S-;
k represents 0 or 1; m represents an integer of 0 to 4; and n represents 0 or 1.

Suitable examples of the substituent represented by R ^1c and R ^2c include an alkyl group and an aryl group, and an alkyl group is preferable. The number of carbon atoms in the alkyl group is preferably 1 to 15, and more preferably 1 to 10. The alkyl group may be linear, branched, or cyclic. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an aryl group, an alkenyl group, an alkynyl group, and a heterocyclic group. The number of carbon atoms in the aryl group is preferably 6 to 20, more preferably 6 to 12, even more preferably 6 to 10, and particularly preferably 6. The aryl group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, and a heterocyclic group.
R ^2c is preferably an alkyl group having a branched or cyclic structure.

Examples of the substituent represented by R ^3c include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, and an acyl group, and an acyl group is preferable. The acyl group has the same meaning as the acyl group in R ^1a of formula (OX-1).

L ^1c represents a single bond or CR ^11c R ^12c , and R ^11c and R ^12c each independently represent a hydrogen atom, an alkyl group, or an aryl group. The alkyl group and aryl group in R ^11c and R ^12c have the same meaning as the alkyl group and aryl group in R ^1c and R ^2c . When k=1, L ^1c is preferably a single bond.

X ^1c represents -C-, -N-, -O- or -S-, and is preferably -O- or -S-.

Ar ^1c represents a (k+m+1)-valent aromatic ring group or a (k+m+1)-valent heterocyclic group, and is preferably a (k+m+1)-valent aromatic ring group. The aromatic ring group is preferably a benzene ring group or a naphthalene ring group, and more preferably a benzene ring group.

^Ar2c represents a (k+2)-valent aromatic ring group or a (k+2)-valent heterocyclic group, and is preferably a (k+2)-valent aromatic ring group. The aromatic ring group is preferably a benzene ring group or a naphthalene ring group, and more preferably a benzene ring group.

k represents 0 or 1, and is preferably 0.
m represents an integer of 0 to 4, preferably 0 or 1, and more preferably 1.
n represents 0 or 1, and is preferably 0.

Specific examples of preferred oxime compounds in this disclosure are shown below. However, this disclosure is not limited to these.

The oxime compound is preferably a compound having a maximum absorption wavelength in the wavelength range of 350 to 500 nm, more preferably a compound having a maximum absorption wavelength in the wavelength range of 360 to 480 nm. From the viewpoint of sensitivity, the molar absorption coefficient of the oxime compound at a wavelength of 365 nm or 405 nm is preferably high, more preferably 1000 to 300,000, even more preferably 2000 to 300,000, and particularly preferably 5000 to 200,000. The molar absorption coefficient of the compound can be measured using a known method. For example, it is preferable to measure using a spectrophotometer (Varian Cary-5 spectrophotometer) at a concentration of 0.01 g/L using ethyl acetate as a solvent.

As the photopolymerization initiator, a bifunctional or trifunctional or more functional photoradical polymerization initiator may be used. By using such a photoradical polymerization initiator, one of the photoradical polymerization initiators
Since two or more radicals are generated from the molecule, good sensitivity can be obtained. In addition, when a compound having an asymmetric structure is used, the crystallinity is reduced and the solubility in a solvent or the like is improved, so that precipitation is less likely to occur over time, and the stability of the curable composition over time can be improved. Specific examples of bifunctional or trifunctional or higher functional photoradical polymerization initiators include the compounds described in paragraph 0148 of WO 2022/065215.

The content of the photopolymerization initiator in the total solid content of the curable composition is preferably 1% by mass to 10% by mass. The lower limit is preferably 1% by mass or more, and more preferably 2% by mass or more. The upper limit is preferably 10% by mass or less, and more preferably 8% by mass or less. In the curable composition of the present disclosure, only one type of photopolymerization initiator may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount thereof is within the above range.

<Radically curable compound>
The curable composition according to the present disclosure comprises a radically curable compound (C).
The radically curable compound may, for example, be a compound having an ethylenically unsaturated group.
Examples of the resin-type radical curable compound include the resin containing a structural unit having a radical polymerizable group as described above. The weight average molecular weight (Mw) of the resin-type polymerizable compound is preferably 3,000 to 2,000,000. The upper limit of the weight average molecular weight is more preferably 1,000,000 or less, and even more preferably 500,000 or less. The lower limit of the weight average molecular weight is more preferably 3,000 or more, and even more preferably 5,000 or more.

As the radical curable compound, it is possible to use a radical curable compound (C1) having a molecular weight of less than 3000. Hereinafter, the radical curable compound (C1) having a molecular weight of less than 3000 is also simply referred to as the curable compound (C1).
The radically curable compound (C1) having a molecular weight of less than 3000 may be a monomer-type radically curable compound, that is, a monomer having a radically polymerizable group (hereinafter also referred to as a "polymerizable monomer").
The molecular weight of the monomer-type radically curable compound (e.g., polymerizable monomer) is less than 3,000, preferably 2,000 or less, and more preferably 1,500 or less. The lower limit of the molecular weight of the polymerizable monomer is preferably 100 or more, and more preferably 200 or more.

The compound having an ethylenically unsaturated group as a polymerizable monomer is preferably a 3-15 functional (meth)acrylate compound, and more preferably a 3-6 functional (meth)acrylate compound. Specific examples include the compounds described in paragraph 0128 of WO 2022/085485 and JP 2017-194662 A, the contents of which are incorporated herein by reference.

As a compound having an ethylenically unsaturated group, the compounds described in paragraphs 0129 to 0137 of WO 2022/085485 can also be used. The compound having an ethylenically unsaturated group may be a compound having an acid group such as a carboxy group, a sulfo group, or a phosphate group, a compound having a caprolactone structure, a compound having an alkyleneoxy group, or a compound having a fluorene skeleton.

As the compound having an ethylenically unsaturated group, it is also preferable to use UA-7200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), DPHA-40H (manufactured by Nippon Kayaku Co., Ltd.), UA-306H, UA-306T, UA-306I, AH-600, T-600, AI-600, LINC-202UA (manufactured by Kyoeisha Chemical Co., Ltd.), 8UH-1006, 8UH-1012 (all manufactured by Taisei Fine Chemical Co., Ltd.), Light Acrylate POB-A0 (manufactured by Kyoeisha Chemical Co., Ltd.), and the like.

In the curable composition according to the present disclosure, only one type or two or more types of radical curable compounds C may be used. When two or more types are used, it is preferable that the total amount thereof is within the above range.
The content of the radical curable compound (C) is preferably 0.1% by mass to 50% by mass based on the total solid content of the curable composition. The lower limit is more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The upper limit is more preferably 45% by mass or less, and even more preferably 40% by mass or less.

In the curable composition according to the present disclosure, from the viewpoint of suppressing outgassing and coating unevenness, the content of the radically curable compound (C1) having a molecular weight of less than 3000 among the radically curable compounds (C) is preferably less than 15% by mass, more preferably 14% by mass or less, even more preferably 13% by mass or less, and particularly preferably 12% by mass or less, based on the total solid content of the curable composition. In addition, the content of the radically curable compound (e.g., polymerizable monomer) having a molecular weight of less than 3000 may be zero (0)% by mass or more, preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total solid content of the curable composition.

The ratio W _C1 /W _A of the content (W _C1 ) of the radical curing compound having a molecular weight of less than 3000 to the content (W _A ) of the radical polymerization initiator represented by formula (1) is preferably less than 5 (W _C1 /W _A < 5) in mass ratio. The ratio W _C1 /W _A is more preferably W _C1 /W _A < 4, and even more preferably W _C1 /W _A < 3. It is also preferable to set it to 0.1 ≦ W _C1 /W _A , and more preferably to set it to 0.5 ≦ W _C1 /W _A.

<Resin Having Crosslinkable Group and Graft Chain>
The curable composition of the present disclosure contains a resin having a crosslinkable group and a graft chain (hereinafter, may be referred to as "resin (B1)"). The resin (B1) is not particularly limited as long as it has a crosslinkable group and a graft chain in the molecule. The resin (B1) corresponds to a radical curable compound by having a radical polymerizable group as a crosslinkable group.

The graft chain in resin (B1) is not particularly limited, and is preferably at least one selected from the group consisting of polyether chains, polyester chains, and poly(meth)acrylic chains.

The weight average molecular weight of the graft chain is preferably 1,000 or more, and more preferably 2,000 or more.

In resin (B1), the content of the structural unit having a graft chain is preferably 0.1 mol% to 50 mol% relative to the total structural units, more preferably 1 mol% to 30 mol%, and even more preferably 5 mol% to 20 mol%.

Preferable examples of the graft chain in resin (B1) include polyether chains, polyester chains, and poly(meth)acrylic chains.

When the graft chain is a polyether chain, it preferably has an alkylene oxide structure [-O(CH ₂ ) _a -, a≧2], a cyclic ether structure, etc. As the polyether chain having an alkylene oxide structure, from the viewpoint of improving the polymerization reactivity and improving the pattern formability, it is preferable that the polyether chain has an alkylene oxide structure in which a is 2 to 30, and more preferably has an ethylene oxide structure or a propylene oxide structure.

Monomers that can be used in the polyether chain include, for example, cyclic ethers such as ethylene oxide, propylene oxide, and 1,2-butylene oxide.

When the graft chain is a polyester chain, a polyester chain having the following partial structure is preferable.
-O(CH ₂ ) _b -C(=O)- [b≧2]
The polyester chain preferably has a structure in which b is 2 to 20, more preferably has a structure in which b is 2 to 15, and further preferably has a structure in which b is 4 to 10, in terms of improving the polymerization reactivity and improving the pattern formability.

In addition to the above, the graft chain preferably has an amide group (NHCO). The graft chain is preferably a polyester chain having, for example, the following partial structure.
-NHC(=O)-(O(CH ₂ ) _b -C(=O)) _b2 - [b≧2]
In the above partial structure, b is preferably an integer of 2 to 15, and more preferably an integer of 4 to 10. b2 is preferably an integer of 5 to 15, and more preferably an integer of 7 to 12.
From the viewpoint of improving the polymerization reactivity and improving the pattern formability, the resin (B1) preferably has a structural unit represented by the following formula (5).

In the constitutional unit represented by formula (5), from the viewpoint of improving the polymerization reactivity and improving the pattern formability, b is preferably 2 to 7, and more preferably 4 to 6. b2 is preferably 5 to 15, and more preferably 7 to 12. In addition, L represents an alkylene group, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents a branched or linear alkyl group having 1 to 12 carbon atoms (preferably having 4 to 12 carbon atoms) or a branched or linear alkoxy group having 1 to 12 carbon atoms.

Monomers that can be used in polyester chains include, for example, cyclic lactones such as caprolactone, valerolactone, and propiolactone.

When the graft chain is a (meth)acrylic chain, it is preferable that it has an addition polymerization chain of a monomer having an ethylenically unsaturated double bond.

Monomers having an ethylenically unsaturated double bond include radically polymerizable monomers, such as (meth)acrylic acid, (meth)acrylic esters, and (meth)acrylamides.

To form the graft chain, the above-mentioned cyclic ethers, cyclic lactones, and radical polymerizable monomers can be used in combination.

It is also preferable that the resin having a crosslinkable group and a graft chain has a constitutional unit represented by the following formula (A) or formula (B) as a structure including a main chain and a graft chain.

In formula (A), R ₁ represents a hydrogen atom or an alkyl group. The alkyl group in R ₁ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

In formula (A) and formula (B), L represents a single bond or a divalent organic group, X represents O or S, and Polym represents a graft chain.

The divalent organic group in L includes an alkylene group, a urethane group (-NHCOO-), etc., and is preferably an organic group having 1 to 8 carbon atoms (preferably an alkylene group), or a divalent group in which an organic group having 1 to 8 carbon atoms (preferably an alkylene group) is bonded to a urethane group.

Furthermore, L is preferably a divalent group represented by the following formula:

L ₁₁ and L ₁₂ each independently represent a single bond or a divalent organic group, and R ₁₁ and R ₁₂ each independently represent O or NH.
The divalent organic group for L ₁₁ and L ₁₂ includes, for example, an alkylene group, and is preferably an alkylene group having 1 to 8 carbon atoms.

In formula (B), Y represents a trivalent organic group, and the two Zs each independently represent O or NH.

The trivalent organic group for Y is preferably an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as the following tertiary alkyl groups. R can be a single bond or an alkylene group.

The alkylene group for R is preferably an alkylene group having 1 to 3 carbon atoms. Examples of the trivalent organic group include the following Group 1 and Group 2 (where three *s represent bonds), and of these, Group 2 is preferred.

In the graft chain, it is preferable that the chain does not have a highly polar functional group (COOH, _SO3H , _PO3H , OH, _NH2 , _NR2 , etc.) in order to increase the steric repulsion and improve the dispersion stability.

The crosslinkable group is not particularly limited, and is preferably at least one group selected from the group consisting of an ethylenically unsaturated group and a cyclic ether group. Among them, from the viewpoint of outgassing suppression, the crosslinkable group preferably has a (meth)acryloyl group, an epoxy group, or an oxetane group.
The crosslinkable group may be introduced into the graft chain, into a side chain terminal other than the graft chain, or into the main chain terminal. From the viewpoint of dispersibility, it is preferable that the crosslinkable group is introduced into a side chain terminal other than the graft chain.

Examples of methods for introducing a crosslinkable group into a resin include a method of adding a (meth)acrylate compound having an epoxy group to a resin having a carboxylic acid, a method of adding a (meth)acrylate compound having a carboxylic acid to a resin having an epoxy group, a method of adding a (meth)acrylate compound having an isocyanate group to a resin having a hydroxyl group, and a method of adding a (meth)acrylate compound having a hydroxyl group to a resin having an isocyanate group.
When an oxetane group is introduced as a crosslinkable group, an example of a method for introducing an oxetane group is to radically polymerize OXE-10 (oxetane acrylate: manufactured by Osaka Organic Chemical Industry Co., Ltd.) or OXE-30 (oxetane methacrylate: manufactured by Osaka Organic Chemical Industry Co., Ltd.) to synthesize a resin having an oxetane structure.

From the viewpoint of dispersion stability, the resin having a crosslinkable group and a graft chain preferably has an ionic bond, and the ionic bond is most preferably a salt of a carboxylic acid and a quaternary amine.
From the viewpoint of dispersion stability, the resin having a crosslinkable group and a graft chain preferably has a constituent unit having a salt structure of a carboxylic acid and a quaternary amine.

The content of the structural units having a crosslinkable group in resin (B1) is preferably 5 mol% to 90 mol%, more preferably 10 mol% to 80 mol%, and even more preferably 20 mol% to 70 mol%, based on the total amount of structural units.

The resin (B1) preferably has at least one group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group, and among these, it is more preferable that the resin (B1) has a carboxylic acid group.
These groups are preferably contained in the resin (B1) so as to satisfy the preferred range of the acid value described below.

From the viewpoint of alkali developability, the resin (B1) is preferably an acrylic resin.
Here, the resin (B1) being an acrylic resin means that it is a resin containing a main chain formed by polymerization of a (meth)acrylic monomer.

The resin (B1) is preferably an acrylic resin having a poly(meth)acrylic chain, polyester chain, or polyether chain as a graft chain, a (meth)acryloyl group as a crosslinkable group, and a carboxylic acid group.

The weight average molecular weight of resin (B1) is preferably 3,000 to 50,000, more preferably 5,000 to 30,000, and even more preferably 10,000 to 25,000.

The acid value of resin (B1) is preferably 30 mgKOH/g to 200 mgKOH/g, and more preferably 40 mgKOH/g to 100 mgKOH/g.

Specific examples of resin (B1) include C2-1 to C2-6 described in the examples below.

The curable composition according to the present disclosure particularly preferably contains a radical polymerization initiator in which X is (X-2), (X-4), (X-6) or (X-8) in formula (1), and R ₁₁ and R ₁₂ are (R-6), (R-7), (R-12), (R-13) or (R-14), and a resin (B1) having a structural unit represented by formula (5). Furthermore, it is most preferable that the curable composition according to the present disclosure contains a radical polymerization initiator in which X is (X-2), (X-4) or (X-6) in formula (1), and R ₁₁ and R ₁₂ are (R-6), and a resin (B1) having a structural unit represented by formula (5).

Specific examples of the resin (B1) include, for example, the "resin having an oxetane group in the side chain" described in WO 2021/182268, the "dispersant resin having a crosslinkable group, an acid group, and a polyester chain as a graft chain" described in WO 2018/037812, the "polyester-type dispersion resin having an oxetane group or an unsaturated crosslinkable group in the graft portion" described in JP 2018-101039 A, and the "polyester-type dispersion resin having an oxetane group or an unsaturated crosslinkable group in the graft portion" described in WO 2018/037812. Examples of such resins include the "graft dispersant resin having a quaternary ammonium salt and a carbon-carbon unsaturated group as a crosslinkable group" described in WO 2020/166510, the "polyimide or polyamic acid dispersant resin having a crosslinkable group and a graft chain" described in WO 2022/019253, and the "dispersant resin having a crosslinkable group and a graft chain, and in which the main chain has both ester bonds and amide bonds" described in WO 2022/019255.

The curable composition of the present disclosure may contain one type of resin (B1) alone, or may contain two or more types of resin (B1).
The content of the resin (B1) is preferably from 5 to 40% by mass, and more preferably from 10 to 30% by mass, based on the total solid content of the curable composition.

<Resins other than Resin (B1)>
The curable composition according to the present disclosure may contain a resin other than the resin (B1). Hereinafter, when simply referring to a "resin", this refers to a resin other than the resin (B1).
As the resin other than the resin (B1), a resin serving as a radically curable compound, that is, a resin having a radically polymerizable group, can be used.
The resin having a radically polymerizable group also corresponds to a radically curable compound.
The curable composition according to the present disclosure may further contain a resin other than the radically curable compound.

The weight average molecular weight of the resin is preferably 3,000 to 2,000,000. The upper limit is preferably 1,000,000 or less, and more preferably 500,000 or less. The lower limit is preferably 4,000 or more, and more preferably 5,000 or more.

Examples of the resin include (meth)acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyester resin, styrene resin, vinyl acetate resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyurethane resin, polyurea resin, etc. One of these resins may be used alone, or two or more may be mixed and used. As the cyclic olefin resin, norbornene resin is preferable from the viewpoint of improving heat resistance.
Commercially available norbornene resins include, for example, the ARTON series (for example, ARTON F4520) manufactured by JSR Corporation. Examples of the resin include those described in the examples of International Publication No. 2016/088645, those described in JP-A-2017-057265, those described in JP-A-2017-032685, those described in JP-A-2017-075248, those described in JP-A-2017-066240, those described in JP-A-2017-167513, those described in JP-A-2017-173787, and those described in paragraphs 0041 to 0060 of JP-A-2017-206689. Resins described in paragraphs 0022 to 0071 of JP 2018-010856 A, blocked polyisocyanate resins described in JP 2016-222891 A, resins described in JP 2020-122052 A, resins described in JP 2020-111656 A, resins described in JP 2020-139021 A, resins containing a structural unit having a ring structure in the main chain and a structural unit having a biphenyl group in the side chain described in JP 2017-138503 A can also be used. In addition, resins having a fluorene skeleton can also be preferably used as the resin. For resins having a fluorene skeleton, the description in U.S. Patent Application Publication No. 2017/0102610 can be referred to, the contents of which are incorporated herein by reference. In addition, as the resin, the resin described in paragraphs 0199 to 0233 of JP 2020-186373 A, the alkali-soluble resin described in JP 2020-186325 A, the resin represented by formula 1 described in Korean Patent Publication No. 10-2020-0078339 A, and the copolymer containing an epoxy group and an acid group described in WO 2022/030445 can also be used.

It is preferable to use a resin having an acid group as the resin. Examples of the acid group include a carboxy group, a phosphate group, a sulfo group, and a phenolic hydroxy group. These acid groups may be of only one type, or of two or more types. The resin having an acid group can be used, for example, as an alkali-soluble resin. The acid value of the resin having an acid group is preferably 30 to 500 mgKOH/g. The lower limit is preferably 50 mgKOH/g or more, and more preferably 70 mgKOH/g or more. The upper limit is preferably 400 mgKOH/g or less, more preferably 200 mgKOH/g or less, even more preferably 150 mgKOH/g or less, and most preferably 120 mgKOH/g or less.

The resin may also be the compound described in paragraphs 0056 to 0059 of WO 2022/085485.

As the resin, it is also preferable to use a resin having a polymerizable group. Examples of the polymerizable group include an ethylenically unsaturated group and a cyclic ether group. Among them, from the viewpoint of outgassing suppression, it is preferable to use a resin having a (meth)acryloyl group, an epoxy group, or an oxetane group.

In addition, as the resin, a resin having at least one type of structural unit (hereinafter also referred to as structural unit Ep) selected from the structural unit represented by formula (Ep-1) and the structural unit represented by formula (Ep-2) (hereinafter also referred to as resin Ep) can also be used.
p may contain only one of the structural units represented by formula (Ep-1) and the structural units represented by formula (Ep-2), or may contain both the structural units represented by formula (Ep-1) and the structural units represented by formula (Ep-2). When both structural units are contained, the ratio of the structural units represented by formula (Ep-1) to the structural units represented by formula (Ep-2) is preferably, in molar ratio, structural units represented by formula (Ep-1): structural units represented by formula (Ep-2) = 5:95 to 95:5, more preferably 10:90 to 90:10, and even more preferably 20:80 to 80:20.

In formulae (Ep-1) and (Ep-2), L ¹ represents a single bond or a divalent linking group, and R ¹ represents a hydrogen atom or a substituent. Examples of the substituent represented by R ¹ include an alkyl group and an aryl group, and an alkyl group is preferable. The number of carbon atoms of the alkyl group is preferably 1 to 10, more preferably 1 to 5, and even more preferably 1 to 3. R ¹ is preferably a hydrogen atom or a methyl group. Examples of the divalent linking group represented by L ¹ include an alkylene group (preferably an alkylene group having 1 to 12 carbon atoms), an arylene group (preferably an arylene group having 6 to 20 carbon atoms), -NH-, -SO-, -SO ₂ -, -CO-, -O-, -COO-, -OCO-, -S-, and a group formed by combining two or more of these. The alkylene group may be linear, branched, or cyclic, and is preferably linear or branched. The alkylene group may have a substituent or may be unsubstituted. Examples of the substituent include a hydroxy group and an alkoxy group.

The content of the above-mentioned structural unit Ep in the resin Ep is preferably 1 mol% to 100 mol% of all structural units of the resin Ep. The upper limit is more preferably 90 mol% or less, and even more preferably 80 mol% or less. The lower limit is more preferably 2 mol% or more, and even more preferably 3 mol% or more.

The resin Ep may have other structural units in addition to the structural unit Ep. Examples of the other structural units include a structural unit having an acid group and a structural unit having an ethylenically unsaturated group.

Examples of the acid group include a phenolic hydroxy group, a carboxy group, a sulfo group, and a phosphate group, with a phenolic hydroxy group or a carboxy group being preferred, and a carboxy group being more preferred.

Examples of ethylenically unsaturated groups include vinyl groups, styrene groups, (meth)allyl groups, and (meth)acryloyl groups.

When the resin Ep contains a structural unit having an acid group, the content of the structural unit having an acid group in the resin Ep is preferably 5 mol% to 85 mol% of all structural units of the resin Ep. The upper limit is more preferably 60 mol% or less, and even more preferably 40 mol% or less. The lower limit is more preferably 8 mol% or more, and even more preferably 10 mol% or more.

When the resin Ep contains a structural unit having an ethylenically unsaturated group, the content of the structural unit having an ethylenically unsaturated group in the resin Ep is preferably 1 mol% to 65 mol% of all structural units of the resin Ep. The upper limit is more preferably 45 mol% or less, and even more preferably 30 mol% or less. The lower limit is more preferably 2 mol% or more, and even more preferably 3 mol% or more.

The resin Ep preferably further contains a structural unit having an aromatic hydrocarbon ring. The aromatic hydrocarbon ring is preferably a benzene ring or a naphthalene ring, and is preferably a benzene ring. The aromatic hydrocarbon ring may have a substituent. Examples of the substituent include an alkyl group. When the resin having a cyclic ether group contains a structural unit having an aromatic hydrocarbon ring, the content of the structural unit having an aromatic hydrocarbon ring is preferably 1 mol% to 65 mol% of the total structural units of the resin having a cyclic ether group. The upper limit is more preferably 45 mol% or less, and even more preferably 30 mol% or less. The lower limit is more preferably 2 mol% or more, and even more preferably 3 mol% or more. Examples of structural units having an aromatic hydrocarbon ring include structural units derived from monofunctional polymerizable compounds having an aromatic hydrocarbon ring, such as vinyl toluene and benzyl (meth)acrylate.

As the resin, it is also preferable to use a resin containing a structural unit derived from a compound represented by the following formula (X):

In formula (X), R ¹ represents a hydrogen atom or a methyl group, R ²¹ and R ²² each independently represent an alkylene group, and n represents an integer of 0 to 15. The number of carbon atoms in the alkylene group represented by R ²¹ and R ²² is preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and particularly preferably 2 or 3. n represents an integer of 0 to 15, preferably an integer of 0 to 5, more preferably an integer of 0 to 4, and even more preferably an integer of 0 to 3.

Examples of the compound represented by formula (X) include ethylene oxide or propylene oxide modified (meth)acrylate of paracumylphenol. Commercially available products include Aronix M-110 (manufactured by Toagosei Co., Ltd.).

As the resin, it is also preferable to use a resin having an aromatic carboxy group (hereinafter, also referred to as resin Ac). In resin Ac, the aromatic carboxy group may be contained in the main chain of the structural unit, or may be contained in the side chain of the structural unit. It is preferable that the aromatic carboxy group is contained in the main chain of the repeating unit. In this specification, the aromatic carboxy group refers to a group having a structure in which one or more carboxy groups are bonded to an aromatic ring. In the aromatic carboxy group, the number of carboxy groups bonded to the aromatic ring is preferably 1 to 4, and more preferably 1 to 2.

The resin Ac is preferably a resin containing at least one type of structural unit selected from the structural unit represented by the following formula (Ac-1) and the structural unit represented by the following formula (Ac-2).

In formula (Ac-1), Ar ¹ represents a group containing an aromatic carboxy group, L ¹ represents --COO-- or CONH--, and L ² represents a divalent linking group.
In formula (Ac-2), Ar ¹⁰ represents a group containing an aromatic carboxy group, L ¹¹ represents --COO-- or CONH--, L ¹² represents a trivalent linking group, and P ¹⁰ represents a polymer chain.

In formula (Ac-1), examples of the group containing an aromatic carboxy group represented by Ar ¹ include structures derived from aromatic tricarboxylic anhydrides, structures derived from aromatic tetracarboxylic anhydrides, etc. Examples of the aromatic tricarboxylic anhydrides and aromatic tetracarboxylic anhydrides include compounds having the following structures.

In the above formula, Q ¹ represents a single bond, —O—, —CO—, —COOCH ₂ CH ₂ OCO—, —SO ₂ —, —C(CF ₃ ) ₂ —, a group represented by the following formula (Q-1) or a group represented by the following formula (Q-2).

The group containing an aromatic carboxy group represented by Ar ¹ may have a polymerizable group. The polymerizable group is preferably an ethylenically unsaturated group or a cyclic ether group, and more preferably an ethylenically unsaturated group.
Specific examples of the group containing an aromatic carboxy group represented by Ar ¹ include a group represented by the following formula (Ar-11), a group represented by the following formula (Ar-12), and a group represented by the following formula (Ar-13).

In formula (Ar-11), n1 represents an integer of 1 to 4, preferably 1 or 2, and more preferably 2.
In formula (Ar-12), n2 represents an integer of 1 to 8, preferably an integer of 1 to 4, more preferably 1 or 2, and even more preferably 2.
In formula (Ar-13), n3 and n4 each independently represent an integer of 0 to 4, and are preferably an integer of 0 to 2, more preferably 1 or 2, and further preferably 1. However, at least one of n3 and n4 is an integer of 1 or more.
In formula (Ar-13), Q ¹ represents a single bond, —O—, —CO—, —COOCH ₂ CH ₂ OCO—, —SO ₂ —, —C(CF ₃ ) ₂ —, a group represented by the above formula (Q-1) or a group represented by the above formula (Q-2).
In formulae (Ar-11) to (Ar-13), *1 represents the bonding position to ^L1 .

In formula (Ac-1), ^L1 represents --COO-- or CONH--, and preferably represents --COO--.

In formula (Ac-1), the divalent linking group represented by L ² includes an alkylene group, an arylene group, -O-, -CO-, -COO-, -OCO-, -NH-, -S-, and a group combining two or more of these. The number of carbon atoms in the alkylene group is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 15. The alkylene group may be linear, branched, or cyclic. The number of carbon atoms in the arylene group is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 10. The alkylene group and the arylene group may have a substituent. Examples of the substituent include a hydroxy group. The divalent linking group represented by L ² is preferably a group represented by -L ^2a -O-. L ^2a is selected from the group consisting of an alkylene group, an arylene group, a group formed by combining an alkylene group and an arylene group, and at least one selected from the group consisting of an alkylene group and an arylene group, -O-, -CO-, -COO-, -OCO-, -NH- and S.
- and a group combining at least one selected from the group consisting of aryl, aryloxy ...

The aromatic carboxyl-containing group represented by Ar ¹⁰ in formula (Ac-2) has the same meaning as Ar ¹ in formula (Ac-1), and preferred embodiments are also the same.

In formula (Ac-2), L ¹¹ represents —COO— or CONH—, and preferably represents —COO—.

In formula (Ac-2), the trivalent linking group represented by L ¹² includes a hydrocarbon group, -O-, -CO-, -COO-, -OCO-, -NH-, -S-, and a group combining two or more of these. Examples of the hydrocarbon group include an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The number of carbon atoms in the aliphatic hydrocarbon group is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 15. The aliphatic hydrocarbon group may be linear, branched, or cyclic. The number of carbon atoms in the aromatic hydrocarbon group is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 10. The hydrocarbon group may have a substituent. Examples of the substituent include a hydroxyl group. The trivalent linking group represented by L ¹² is preferably a group represented by the following formula (L12-1), and more preferably a group represented by the following formula (L12-2).

In formula (L12-1), L ^12b represents a trivalent linking group, X ¹ represents S, *1 represents the bonding position to L ¹¹ in formula (Ac-2), and *2 represents the bonding position to P ¹⁰ in formula (Ac-2). Examples of the trivalent linking group represented by L ^12b include a hydrocarbon group; and a group in which a hydrocarbon group is combined with at least one selected from -O-, -CO-, -COO-, -OCO-, -NH-, and -S-, and the like. A hydrocarbon group or a group in which a hydrocarbon group is combined with -O- is preferred.

In formula (L12-2), L ^12c represents a trivalent linking group, X ¹ represents S, *1 represents the bonding position to L ¹¹ in formula (Ac-2), and *2 represents the bonding position to P ¹⁰ in formula (Ac-2). Examples of the trivalent linking group represented by L ^12c include a hydrocarbon group; and a group in which a hydrocarbon group is combined with at least one selected from -O-, -CO-, -COO-, -OCO-, -NH-, and -S-, and the like, with a hydrocarbon group being preferred.

In formula (Ac-2), P ¹⁰ represents a polymer chain. The polymer chain represented by P ¹⁰ preferably has at least one structural unit selected from a poly(meth)acrylic structural unit, a polyether structural unit, a polyester structural unit, and a polyol structural unit. The weight average molecular weight of the polymer chain P ¹⁰ is preferably 500 to 20,000. The lower limit is more preferably 1,000 or more. The upper limit is more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 3,000 or less. If the weight average molecular weight of P ¹⁰ is within the above range, the dispersibility of the coloring material in the curable composition is excellent. When the resin having an aromatic carboxy group is a resin having a structural unit represented by formula (Ac-2), this resin is preferably used as a dispersant.

The polymer chain represented by P ¹⁰ may contain a polymerizable group. The polymerizable group may be an ethylenically unsaturated group.

The curable composition according to the present disclosure preferably contains a resin as a dispersant.
Examples of the dispersant include an acidic dispersant (acidic resin) and a basic dispersant (basic resin). Here, the acidic dispersant (acidic resin) refers to a resin in which the amount of acid groups is greater than the amount of basic groups. As the acidic dispersant (acidic resin), a resin in which the amount of acid groups is 70 mol% or more is preferable when the total amount of the acid groups and the amount of the basic groups is 100 mol%. The acid group possessed by the acidic dispersant (acidic resin) is preferably a carboxy group. The acid value of the acidic dispersant (acidic resin) is preferably 10 mgKOH/g to 105 mgKOH/g. In addition, the basic dispersant (basic resin) refers to a resin in which the amount of basic groups is greater than the amount of acid groups. As the basic dispersant (basic resin), a resin in which the amount of basic groups is greater than 50 mol% is preferable when the total amount of the acid groups and the amount of the basic groups is 100 mol%.
The basic group of the basic dispersant is preferably an amino group. When an amino group such as polyethyleneimine is present, the hydrolysis reaction of the polymerization initiator (particularly, a polymerization initiator having a structure in which an oxime group and a carbonyl group are adjacent to each other) is likely to proceed. In the present disclosure, the use of the radical polymerization initiator represented by the above-mentioned formula (1) effectively suppresses the hydrolysis reaction, resulting in better storage stability over time.

The resin used as the dispersant is preferably a resin having a graft chain other than the above-mentioned resin (B1). For details of the resin having a graft chain, i.e., the graft polymer, the description in paragraphs 0025 to 0094 of JP2012-255128A can be referred to, and the contents thereof are incorporated herein by reference.
From the viewpoint of dispersion stability, it is preferable that the resin is a resin having a graft chain, the graft chain includes at least one type selected from the group consisting of a polyether chain, a polyester chain, and a polyacrylic chain, and the weight average molecular weight of the graft chain is 1,000 or more.

The resin used as the dispersant is preferably a polyimine-based dispersant containing nitrogen atoms in at least one of the main chain and side chain. The polyimine-based dispersant is preferably a resin having a main chain with a partial structure having a functional group with a pKa of 14 or less, a side chain with 40 to 10,000 atoms, and having a basic nitrogen atom in at least one of the main chain and side chain. There are no particular restrictions on the basic nitrogen atom, so long as it is a nitrogen atom that exhibits basicity. For details of polyimine-based dispersants, please refer to the description in paragraphs 0102 to 0166 of JP 2012-255128 A, the contents of which are incorporated herein by reference.

The resin used as the dispersant is preferably one having a structure in which multiple polymer chains are bonded to a core portion. Examples of such resins include dendrimers (including star-shaped polymers). Specific examples of dendrimers include polymer compounds C-1 to C-31 described in paragraphs 0196 to 0209 of JP2013-043962A.

The resin used as the dispersant is also preferably a resin containing a structural unit having an ethylenically unsaturated group in the side chain. The content of the structural unit having an ethylenically unsaturated group in the side chain is preferably 10 mol% or more of the total structural units of the resin, more preferably 10 mol% to 80 mol%, and even more preferably 20 mol% to 70 mol%.

The resin used as the dispersant is preferably a resin containing an oxetane group on the side chain other than the above-mentioned resin (B1), and more preferably a resin containing a structural unit having an oxetane group on the side chain.
The content of the structural unit having an oxetane group on a side chain in the above resin is preferably 10 mol % or more, more preferably 10 mol % to 80 mol %, and even more preferably 20 mol % to 70 mol %, of all the structural units of the resin.

In addition, as dispersants, resins described in JP 2018-087939 A, block copolymers (EB-1) to (EB-9) described in paragraphs 0219 to 0221 of Japanese Patent No. 6,432,077 A, polyethyleneimine having a polyester side chain described in WO 2016/104803 A, block copolymers described in WO 2019/125940 A, block polymers having an acrylamide structural unit described in JP 2020-066687 A, block polymers having an acrylamide structural unit described in JP 2020-066688 A, dispersants described in WO 2016/104803 A, and the like can also be used.

As the dispersant, polyamic acid type dispersing resins and polyimide type dispersing resins can also be used. As such resins, dispersants described in WO 2022/019253, WO 2022/019254, and WO 2022/019255 can also be used.

Dispersants are also available as commercially available products, and specific examples include the Disperbyk series manufactured by BYK-Chemie (e.g., Disperbyk-111, 161, 2001, etc.), the Solsperse series manufactured by Lubrizol Japan Co., Ltd. (e.g., Solsperse 20000, 76500, etc.), and the Ajisper series manufactured by Ajinomoto Fine-Techno Co., Ltd. In addition, the products described in paragraph 0129 of JP 2012-137564 A and the products described in paragraph 0235 of JP 2017-194662 A can also be used as dispersants.

When the curable composition according to the present disclosure contains a resin as a radical curable compound, the content of the resin is preferably 1% by mass to 70% by mass based on the total solid content of the curable composition. The lower limit is more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The upper limit is more preferably 65% by mass or less, and even more preferably 60% by mass or less.
The content of the resin having an acid group is preferably 1% by mass to 70% by mass based on the total solid content of the curable composition. The lower limit is more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The upper limit is more preferably 65% by mass or less, and even more preferably 60% by mass or less.
The content of the alkali-soluble resin is preferably 1% by mass to 70% by mass based on the total solid content of the curable composition. The lower limit is more preferably 2% by mass or more, even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The upper limit is more preferably 65% by mass or less, and even more preferably 60% by mass or less.
When the curable composition according to the present disclosure contains a resin as a dispersant, the content of the resin as a dispersant is preferably 0.1% by mass to 30% by mass with respect to the total solid content of the curable composition. The upper limit is more preferably 25% by mass or less, and even more preferably 20% by mass or less. The lower limit is more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The content of the resin as a dispersant is preferably 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the colorant. The upper limit is more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less. The lower limit is more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 20 parts by mass or more.
The curable composition according to the present disclosure may contain only one type of resin, or may contain two or more types of resins. When two or more types of resins are contained, the total amount thereof is preferably within the above range.

<Coloring material>
The curable composition of the present disclosure preferably further contains a colorant.
The coloring materials include chromatic coloring materials, achromatic coloring materials (black or white), and infrared (IR) absorbing materials.
Examples of chromatic coloring materials include coloring materials having a maximum absorption wavelength in the wavelength range of 400 nm to 700 nm. Examples of coloring materials include green coloring materials, red coloring materials, yellow coloring materials, purple coloring materials, blue coloring materials, and orange coloring materials.
The coloring material may be a pigment or a dye.
From the viewpoints of coloring properties and dispersibility, the colorant is preferably at least one pigment selected from the group consisting of diketopyrrolopyrrole pigments, quinacridone pigments, anthraquinone pigments, perylene pigments, phthalocyanine pigments, isoindoline pigments, quinophthalone pigments, azo pigments, azomethine pigments, and dioxazine pigments, and more preferably at least one pigment selected from the group consisting of diketopyrrolopyrrole pigments, phthalocyanine pigments, and isoindoline pigments.
In addition, a black pigment can be used, and examples of the black pigment that can be used include carbon black and pigments containing titanium atoms or zirconium atoms.

The average primary particle diameter of the pigment is preferably 1 nm to 200 nm. The lower limit is more preferably 5 nm or more, and even more preferably 10 nm or more. The upper limit is more preferably 180 nm or less, even more preferably 150 nm or less, and particularly preferably 100 nm or less. In this specification, the primary particle diameter of the pigment can be determined from an image photograph obtained by observing the primary particles of the pigment with a transmission electron microscope. Specifically, the projected area of the primary particles of the pigment is determined, and the corresponding circle equivalent diameter is calculated as the primary particle diameter of the pigment. In this specification, the average primary particle diameter is the arithmetic mean value of the primary particle diameters of 400 primary particles of the pigment. Furthermore, the primary particles of the pigment refer to independent particles that are not aggregated.
The crystallite size of the pigment, determined from the half-width of a peak derived from any crystal plane in an X-ray diffraction spectrum obtained using CuKα radiation as an X-ray source, is preferably 0.1 nm to 100 nm, more preferably 0.5 nm to 50 nm, even more preferably 1 nm to 30 nm, and particularly preferably 5 nm to 25 nm.

Green colorants include phthalocyanine compounds and squarylium compounds, and are preferably phthalocyanine compounds. The green colorant is preferably a pigment. Specific examples of green colorants include green pigments such as C.I. Pigment Green 7, 10, 36, 37, 58, 59, 62, 63, 64, 65, and 66. In addition, compounds described in paragraphs 0143 to 0149 of International Publication No. 2022/085485, aluminum phthalocyanine compounds described in JP-A-2020-070426, diarylmethane compounds described in JP-A-2020-504758, and green pigments described in The Journal of the Color Materials Association, Vol. 95, No. 4, pp. 80 to 84, 2022, and the like can also be used as green colorants.

The green colorant is preferably C.I. Pigment Green 7, 36, 58, 59, 62, or 63, and more preferably C.I. Pigment Green 7, 36, 58, or 59.

Examples of the red colorant include diketopyrrolopyrrole compounds, anthraquinone compounds, azo compounds, naphthol compounds, azomethine compounds, xanthene compounds, quinacridone compounds, perylene compounds, and thioindigo compounds, and are preferably diketopyrrolopyrrole compounds, anthraquinone compounds, and azo compounds, and more preferably diketopyrrolopyrrole compounds. The red colorant is preferably a pigment. Specific examples of the red colorant include C.I. (Color Index) Pigment Red 1, 2, 3, 4, 5, 6, 7, 9, 10, 14, 17, 22, 23, 31, 38, 41, 48: 1, 48: 2, 48: 3, 48: 4, 49, 49: 1, 49: 2, 52: 1, 52: 2, 53: 1, 57: 1, 60: 1, 63: 1, 66, 67, 81: 1, 81: 2, 81: 3, 83, 88, 90, 105, 112, 119, 122, 123, 144, 146, 149, Examples of red pigments include 150, 155, 166, 168, 169, 170, 171, 172, 175, 176, 177, 178, 179, 184, 185, 187, 188, 190, 200, 202, 206, 207, 208, 209, 210, 216, 220, 224, 226, 242, 246, 254, 255, 264, 269, 270, 272, 279, 291, 294, 295, 296, and 297. In addition, the compound described in paragraph 0034 of WO 2022/085485 can also be used as a red colorant. As a red colorant, Lumogen F Orange 240 (manufactured by BASF, red pigment, perylene pigment) can also be used.

The red colorant is preferably C.I. Pigment Red 122, 177, 179, 254, 255, 264, 269, 272, or 291, and more preferably C.I. Pigment Red 177, 254, 264, 272, or 291.

Examples of yellow colorants include azo compounds, azomethine compounds, isoindoline compounds, pteridine compounds, quinophthalone compounds, and perylene compounds. The yellow colorant is preferably a pigment, more preferably an azo pigment, azomethine pigment, isoindoline pigment, pteridine pigment, quinophthalone pigment, or perylene pigment, and even more preferably an azo pigment or azomethine pigment. Specific examples of yellow colorants include C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125 , 126, 127, 128, 129, 137, 138, 139, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 213, 214, 215, 228, 231, 232, 233, 234, 235, 236, and other yellow pigments.

　Also, azobarbituric acid nickel complex having the following structure can be used as a yellow colorant.

In addition, the compounds described in paragraphs 0031 to 0033 of WO 2022/085485 can also be used as yellow colorants.

The yellow colorant is preferably C.I. Pigment Yellow 7, 117, 129, 138, 139, 150, 185, or 215, and more preferably C.I. Pigment Yellow 7, 129, 138, 139, 150, 185, or 215.

Orange colorants include orange pigments such as C.I. Pigment Orange 2, 5, 13, 16, 17:1, 31, 34, 36, 38, 43, 46, 48, 49, 51, 52, 55, 59, 60, 61, 62, 64, 71, and 73.

Examples of purple colorants include purple pigments such as C.I. Pigment Violet 1, 19, 23, 27, 32, 37, 42, 60, and 61.

Examples of blue colorants include C.I. Pigment Blue 1, 2, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 29, 60, 64, 66, 79, 80, 87, and 88. Aluminum phthalocyanine compounds having phosphorus atoms can also be used as blue colorants. Specific examples include the compounds described in paragraphs 0022 to 0030 of JP-A No. 2012-247591 and paragraph 0047 of JP-A No. 2011-157478.

Dyes can also be used as chromatic colorants. There are no particular limitations on the dyes, and any known dyes can be used. Examples include pyrazole azo, anilino azo, triarylmethane, anthraquinone, anthrapyridone, benzylidene, oxonol, pyrazolotriazole azo, pyridone azo, cyanine, phenothiazine, pyrrolopyrazole azomethine, xanthene, phthalocyanine, benzopyran, indigo, and pyrromethene dyes.

A dye polymer can also be used as a chromatic coloring material. The dye polymer is preferably a dye dissolved in an organic solvent before use. The dye polymer may also form particles. When the dye polymer is in the form of particles, it is usually used in a state of being dispersed in a solvent. A dye polymer in a particulate state can be obtained, for example, by emulsion polymerization, and specific examples of the compound and manufacturing method described in JP-A-2015-214682 include the compound described in paragraph 0048 of WO 2022/085485.

Chromatic colorants include diarylmethane compounds described in JP-T-2020-504758, triarylmethane dye polymers described in Korean Patent Publication No. 10-2020-0028160, xanthene compounds described in JP-A-2020-117638, phthalocyanine compounds described in WO-A-2020/174991, and isoindoline compounds described in JP-A-2020-160279. or a salt thereof, a compound represented by formula 1 described in Korean Patent Publication No. 10-2020-0069442, a compound represented by formula 1 described in Korean Patent Publication No. 10-2020-0069730, a compound represented by formula 1 described in Korean Patent Publication No. 10-2020-0069070, a compound represented by formula 1 described in Korean Patent Publication No. 10-2020-0069067, a compound represented by formula 1 described in Korean Patent Publication No. 10 Compounds represented by formula 1 described in JP-A-2020-0069062, halogenated zinc phthalocyanine pigments described in JP-A-6809649, isoindoline compounds described in JP-A-2020-180176, phenothiazine compounds described in JP-A-2021-187913, quinophthalone compounds represented by formula 1 in Korean Patent Publication No. 10-2020-0030759, and Korean Patent Publication No. Polymer dyes described in JP-A-2020-0061793, colorants described in JP-A-2022-029701, isoindoline compounds described in WO 2022/014635, aluminum phthalocyanine compounds described in WO 2022/024926, compounds described in JP-A-2022-045895, and compounds described in WO 2022/050051 can be used. The chromatic colorant may be a rotaxane, and the dye skeleton may be used in the cyclic structure of the rotaxane, in the rod-shaped structure, or in both structures.

Two or more chromatic colorants may be used in combination. When two or more chromatic colorants are used in combination, the color black may be formed by combining two or more chromatic colors.

The black colorant is not particularly limited, and known ones can be used. For example, examples of inorganic black colorants include carbon black, titanium black, zirconium oxynitride, graphite, etc., and carbon black, titanium black, or zirconium oxynitride is preferred, and titanium black or zirconium oxynitride is more preferred. Titanium black is a black particle containing titanium atoms, and low-order titanium oxide or titanium oxynitride is preferred. Titanium black can be surface-modified as necessary for the purpose of improving dispersibility, suppressing aggregation, etc. For example, the surface of titanium black can be coated with silicon oxide, titanium oxide, germanium oxide, aluminum oxide, magnesium oxide, or zirconium oxide. In addition, treatment with a water-repellent substance such as that shown in JP-A-2007-302836 can also be used. Color Index (C.I.) Pigment Black 1, 7 can also be used as the black colorant. It is preferable that titanium black has small primary particle diameters and average primary particle diameters of individual particles. Specifically, the average primary particle size is preferably 10 to 45 nm. Titanium black can also be used as a dispersion. For example, a dispersion containing titanium black particles and silica particles, and in which the content ratio of Si atoms to Ti atoms in the dispersion is adjusted to a range of 0.20 to 0.50, can be mentioned. For the above dispersion, the description in paragraphs 0020 to 0105 of JP-A-2012-169556 can be referred to, and the contents thereof are incorporated herein. Examples of commercially available titanium black products include Titanium Black 10S, 12S, 13R, 13M, 13M-C, 13R-N, and 13M-T (product names: manufactured by Mitsubishi Materials Corporation), Tilack D (product name: manufactured by Ako Kasei Co., Ltd.), and the like. Examples of organic black colorants include bisbenzofuranone compounds, azomethine compounds, perylene compounds, and azo compounds, and bisbenzofuranone compounds and perylene compounds are preferred. Examples of the bisbenzofuranone compound include compounds described in JP-T-2010-534726, JP-T-2012-515233, JP-T-2012-515234, WO 2014/208348, and JP-T-2015-525260, and are available, for example, as "Irgaphor Black" manufactured by BASF. Examples of the perylene compound include C.I. Pigment Black 31 and 32. Examples of the azomethine compound include compounds described in JP-A-01-170601 and JP-A-02-034664, and are available, for example, as "Chromofine Black A1103" manufactured by Dainichi Seika Chemicals Co., Ltd. In addition, as the organic black colorant, perylene black (such as Lumogen Black FK4280) and Paliogen Black S0084 described in paragraphs 0016 to 0020 of JP-A-2017-226821 may be used.

The infrared (IR) absorbing material can be selected from the infrared absorbing materials described below.

The curable composition of the present disclosure may contain one type of colorant alone or two or more types. When two or more types of colorants are used, the total amount of the colorants is preferably in the following range.
From the viewpoint of further exerting the effects of the present disclosure, the content of the coloring material is preferably 10% by mass to 75% by mass based on the total solid content of the curable composition. The upper limit of the content of the coloring material is more preferably 70% by mass or less, and even more preferably 65% by mass or less. The lower limit of the content of the coloring material is more preferably 20% by mass or more, even more preferably 30% by mass or more, and particularly preferably 60% by mass or more.

<Solvent>
The curable composition of the present disclosure preferably contains a solvent. Examples of the solvent include organic solvents. The type of solvent is not particularly limited as long as the solubility of each component and the coatability of the composition are satisfied. Examples of the organic solvent include ester-based solvents, ketone-based solvents, alcohol-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents. For details of these, reference can be made to paragraph number 0223 of International Publication No. 2015/166779, the contents of which are incorporated herein by reference. In addition, ester-based solvents substituted with a cyclic alkyl group and ketone-based solvents substituted with a cyclic alkyl group can also be preferably used. Specific examples of organic solvents include polyethylene glycol monomethyl ether, dichloromethane, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl cellosolve acetate, ethyl lactate, diethylene glycol dimethyl ether, butyl acetate, methyl 3-methoxypropionate, 2-heptanone, 2-pentanone, 3-pentanone, 4-heptanone, cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, cycloheptanone, cyclooctanone, cyclohexyl acetate, cyclopentanone, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether, propylene glycol dimethyl ether, butyl acetate ... Examples of the ethylene glycol monomethyl ether acetate include 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, propylene glycol diacetate, 3-methoxybutanol, methyl ethyl ketone, gamma butyrolactone, sulfolane, anisole, 1,4-diacetoxybutane, diethylene glycol monoethyl ether acetate, butane-1,3-diyl diacetate, dipropylene glycol methyl ether acetate, diacetone alcohol (also known as diacetone alcohol and 4-hydroxy-4-methyl-2-pentanone), 2-methoxypropyl acetate, 2-methoxy-1-propanol, and isopropyl alcohol. However, there are cases where it is better to reduce the amount of aromatic hydrocarbons (benzene, toluene, xylene, ethylbenzene, etc.) used as organic solvents for environmental reasons, etc. (for example, the amount can be 50 ppm (parts per million) by mass or less, 10 ppm by mass or less, or 1 ppm by mass or less, relative to the total amount of organic solvents).

In the present disclosure, it is preferable to use an organic solvent with a low metal content. The metal content of the organic solvent is preferably, for example, 10 parts per billion (ppb) by mass or less. If necessary, an organic solvent with a mass ppt (parts per trillion) level may be used, and such an organic solvent is provided, for example, by Toyo Gosei Co., Ltd. (The Chemical Daily, November 13, 2015).

Methods for removing impurities such as metals from organic solvents include, for example, distillation (molecular distillation, thin-film distillation, etc.) and filtration using a filter. The filter used for filtration preferably has a pore size of 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less. The filter material is preferably polytetrafluoroethylene, polyethylene, or nylon.

The organic solvent may contain isomers (compounds with the same number of atoms but different structures). In addition, the organic solvent may contain only one type of isomer, or multiple types of isomers.

The peroxide content in the organic solvent is preferably 0.8 mmol/L or less, and more preferably substantially free of peroxide.

The content of the solvent in the curable composition is preferably 10% by mass to 95% by mass, more preferably 20% by mass to 90% by mass, and even more preferably 30% by mass to 90% by mass.

Furthermore, from the viewpoint of environmental regulations, it is preferable that the curable composition of the present disclosure is substantially free of environmentally regulated substances. In this disclosure, substantially free of environmentally regulated substances means that the content of environmentally regulated substances in the curable composition is 50 ppm by mass or less, preferably 30 ppm by mass or less, more preferably 10 ppm by mass or less, and particularly preferably 1 ppm by mass or less. Examples of environmentally regulated substances include benzene; alkylbenzenes such as toluene and xylene; and halogenated benzenes such as chlorobenzene. These substances are registered as environmentally regulated substances under the REACH (Registration Evaluation Authorization and Restriction of Chemicals) regulations, the PRTR (Pollutant Release and Transfer Register) Act, the VOC (Volatile Organic Compounds) regulations, etc., and their usage and handling methods are strictly regulated. These compounds may be used as solvents when producing each component used in the curable composition, and may be mixed into the curable composition as a residual solvent. From the viewpoint of human safety and environmental consideration, it is preferable to reduce these substances as much as possible. As a method for reducing the environmentally regulated substances, a method of reducing the environmentally regulated substances by heating or reducing the pressure in the system to a temperature above the boiling point of the environmentally regulated substances and distilling off the environmentally regulated substances from the system can be mentioned. In addition, when distilling off a small amount of environmentally regulated substances, it is useful to perform azeotropy with a solvent having a boiling point equivalent to that of the corresponding solvent in order to increase efficiency. In addition, when a radically polymerizable compound is contained, a polymerization inhibitor or the like may be added and then distilled off under reduced pressure in order to suppress the radical polymerization reaction from proceeding during distillation under reduced pressure and causing crosslinking between molecules. These distillation methods can be used at any stage, such as the stage of the raw materials, the stage of the product obtained by reacting the raw materials (for example, a resin solution or a polyfunctional monomer solution after polymerization), or the stage of the curable composition prepared by mixing these compounds.

<Pigment Derivatives>
The curable composition of the present disclosure may contain a pigment derivative. The pigment derivative is used, for example, as a dispersing aid. Examples of the pigment derivative include a compound having a structure in which an acid group or a basic group is bonded to a pigment skeleton.

Examples of the dye skeleton constituting the pigment derivative include a quinoline dye skeleton, a benzimidazolone dye skeleton, a benzisoindole dye skeleton, a benzothiazole dye skeleton, an iminium dye skeleton, a squarylium dye skeleton, a croconium dye skeleton, an oxonol dye skeleton, a pyrrolopyrrole dye skeleton, a diketopyrrolopyrrole dye skeleton, an azo dye skeleton, an azomethine dye skeleton, a phthalocyanine dye skeleton, a naphthalocyanine dye skeleton, an anthraquinone dye skeleton, a quinacridone dye skeleton, a dioxazine dye skeleton, a perinone dye skeleton, a perylene dye skeleton, a thioindigo dye skeleton, an isoindoline dye skeleton, an isoindolinone dye skeleton, a quinophthalone dye skeleton, an iminium dye skeleton, a dithiol dye skeleton, a triarylmethane dye skeleton, and a pyrromethene dye skeleton.

Examples of the acid group include a carboxy group, a sulfo group, a phosphoric acid group, a boronic acid group, a carboxylic acid amide group, a sulfonic acid amide group, an imide acid group, and salts thereof. Examples of atoms or atomic groups constituting the salt include an alkali metal ion (Li ⁺ , Na ⁺ , K ⁺ , etc.), an alkaline earth metal ion (Ca ²⁺ , Mg ²⁺ , etc.), an ammonium ion, an imidazolium ion, a pyridinium ion, and a phosphonium ion. Examples of the carboxylic acid amide group include a group represented by -NHCOR ^X1 . Examples of the sulfonic acid amide group include a group represented by -NHSO ₂ R ^X2 . Examples of the imide acid group include a group represented by -SO ₂ NHSO ₂ R ^X3 , -CONHSO ₂ R ^X4 , -CONHCOR ^X5 , or SO ₂ NHCOR ^X6 , and more preferably -SO ₂ NHSO ₂ R ^X3 . R ^x1 to R ^x6 each independently represent an alkyl group or an aryl group. The alkyl group and aryl group represented by R ^x1 to R ^x6 may have a substituent. The substituent is preferably a halogen atom, and more preferably a fluorine atom.

Basic groups include amino groups, pyridinyl groups and their salts, salts of ammonium groups, and phthalimidomethyl groups. Atoms or atomic groups that make up the salts include hydroxide ions, halogen ions, carboxylate ions, sulfonate ions, and phenoxide ions.

The pigment derivative may be a pigment derivative having excellent visible transparency (hereinafter, also referred to as a transparent pigment derivative). The maximum molar absorption coefficient (εmax) of the transparent pigment derivative in the wavelength region of 400 nm to 700 nm is preferably 3,000 L mol ^-1 cm- ¹ or less, more preferably 1,000 L mol ^-1 cm ^-1 or less, and even more preferably 100 L mol ^-1 cm ^-1 or less. The lower limit of εmax is, for example, 1 L mol ^-1 cm- ¹ or more, and may be 10 L mol ^-1 cm ^-1 or more.

Specific examples of pigment derivatives include the compounds described in paragraph 0124 of WO 2022/085485, the benzimidazolone compounds or salts thereof described in JP 2018-168244 A, and compounds having an isoindoline skeleton described in general formula (1) of Japanese Patent No. 6996282 A.

The content of the pigment derivative is preferably 1 to 30 parts by mass, and more preferably 3 to 20 parts by mass, relative to 100 parts by mass of the colorant. The total content of the pigment derivative and the colorant is preferably 35% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, and particularly preferably 50% by mass or more, relative to the total solid content of the curable composition. The upper limit is preferably 70% by mass or less, and more preferably 65% by mass or less. Only one type of pigment derivative may be used, or two or more types may be used in combination.

<Chain Transfer Agent>
From the viewpoint of adhesion, it is preferable that the curable composition of the present disclosure further contains a chain transfer agent.
Examples of the chain transfer agent include a thiol compound, a thiocarbonylthio compound, and an aromatic α-methylalkenyl dimer, and the like. Thiol compounds are preferred because they allow easy adjustment of the line width of the pattern even when used in a small amount. In addition, the chain transfer agent is preferably a compound that is less colored.

- Thiol compounds -
The thiol compound is a compound having one or more thiol groups. In particular, the curable composition of the present disclosure preferably contains a compound having two or more thiol groups, i.e., a polyfunctional thiol compound. The upper limit of the number of thiol groups contained in the thiol compound is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, particularly preferably 8 or less, and most preferably 6 or less. The lower limit of the number of thiol groups contained in the thiol compound is preferably 3 or more. From the viewpoint of adhesion, it is particularly preferable that the thiol compound is a compound having 4 thiol groups.

It is also preferred that the thiol compound is a compound derived from a polyfunctional alcohol.

The thiol compound is preferably a compound represented by the following formula (SH-1).
L ¹ - (SH) _n formula (SH-1)
In the formula, SH represents a thiol group, ^L1 represents an n-valent group, and n represents an integer of 1 or more.

In formula (SH-1), examples of the n-valent group represented by L ¹ include a hydrocarbon group, a heterocyclic group, -O-, -S-, -NR-, -CO-, -COO-, -OCO-, -SO ₂ -, or a group consisting of a combination thereof. R represents a hydrogen atom, an alkyl group, or an aryl group, and is preferably a hydrogen atom. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be cyclic or noncyclic. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The hydrocarbon group may have a substituent or may not have a substituent. The cyclic aliphatic hydrocarbon group and the aromatic hydrocarbon group may be a monocyclic ring or a condensed ring. The heterocyclic group may be a monocyclic ring or a condensed ring. The heterocyclic group is preferably a 5-membered ring or a 6-membered ring. The heterocyclic group may be an aliphatic heterocyclic group or an aromatic heterocyclic group. Examples of heteroatoms constituting the heterocyclic group include a nitrogen atom, an oxygen atom, a sulfur atom, etc. The number of carbon atoms constituting ^L1 is preferably 3 to 100, and more preferably 6 to 50.

In formula (SH-1), n represents an integer of 1 or more. The upper limit of n is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, particularly preferably 8 or less, and most preferably 6 or less. The lower limit of n is preferably 2 or more, more preferably 3 or more. It is particularly preferable that n is 4.

Specific examples of thiol compounds include compounds with the following structure. Commercially available thiol compounds include PEMP (manufactured by SC Organic Chemicals Co., Ltd., thiol compound), Suncellar M (manufactured by Sanshin Chemical Industry Co., Ltd., thiol compound), and Karenz MT BD1 (manufactured by Showa Denko K.K., thiol compound).

-Thiocarbonylthio compounds-
The thiocarbonylthio compound is a compound having a thiocarbonylthio group (-S-C(=S)-) in the molecule, and examples thereof include bis(thiocarbonyl)disulfide compounds (compounds represented by formula (SC-1) below), dithioester compounds (compounds represented by formula (SC-2) below), trithiocarbonate compounds (compounds represented by formula (SC-3) below), dithiocarbamate compounds (compounds represented by formula (SC-4) below), and xanthate compounds (compounds represented by formula (SC-5) below).

In formulae (SC-1) to (SC-5), Z ¹ to Z ¹¹ each independently represent a substituent.

Examples of the substituents represented by Z ¹ to Z ¹¹ include an alkyl group, an aryl group, a heteroaryl group, -SR ^Z1 , -NR ^Z1 R ^Z2 , -NR ^Z1 -NR ^Z2 R ^Z3 , -COOR ^Z1 , -OCOR ^Z1 , -CONR ^Z1 R ^Z2 , -P(═O)(OR ^Z1 ) ₂ or -O-P(═O)R ^Z1 R ^Z2 (wherein R ^Z1 , R ^Z2 and R ^Z3 are each independently an alkyl group, an aryl group or a heteroaryl group), etc. Among the above groups, one or more hydrogen atoms bonded to the carbon atom may be substituted with a cyano group, a carboxy group, etc.
The number of carbon atoms in the alkyl group is preferably 1 to 30, more preferably 1 to 15, and still more preferably 1 to 8. The alkyl group may be linear, branched, or cyclic, and is preferably linear or branched.
The aryl group preferably has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and even more preferably 6 to 12 carbon atoms.
The heteroaryl group is preferably a monocyclic heteroaryl group or a fused ring heteroaryl group having 2 to 8 fused rings, more preferably a monocyclic heteroaryl group or a fused ring heteroaryl group having 2 to 4 fused rings. The number of heteroatoms constituting the ring of the heteroaryl group is preferably 1 to 3. The heteroatoms constituting the ring of the heteroaryl group are preferably nitrogen atoms, oxygen atoms, or sulfur atoms. The heteroaryl group is preferably a 5-membered or 6-membered ring. The number of carbon atoms constituting the ring of the heteroaryl group is preferably 3 to 30, more preferably 3 to 18, and even more preferably 3 to 12.

Specific examples of bis(thiocarbonyl) disulfide compounds include tetraethyl thiuram disulfide, tetramethyl thiuram disulfide, bis(n-octyl mercapto-thiocarbonyl) disulfide, bis(n-dodecyl mercapto-thiocarbonyl) disulfide, bis(benzyl mercapto-thiocarbonyl) disulfide, bis(n-butyl mercapto-thiocarbonyl) disulfide, bis(t-butyl mercapto-thiocarbonyl) disulfide, bis(n-heptyl mercapto-thiocarbonyl) disulfide, bis(n- Examples of such disulfides include bis(n-hexylmercapto-thiocarbonyl) disulfide, bis(n-pentylmercapto-thiocarbonyl) disulfide, bis(n-nonylmercapto-thiocarbonyl) disulfide, bis(n-decylmercapto-thiocarbonyl) disulfide, bis(t-dodecylmercapto-thiocarbonyl) disulfide, bis(n-tetradecylmercapto-thiocarbonyl) disulfide, bis(n-hexadecylmercapto-thiocarbonyl) disulfide, and bis(n-octadecylmercapto-thiocarbonyl) disulfide.

Specific examples of dithioester compounds include 2-phenyl-2-propyl benzothioate, 4-cyano-4-(phenylthiocarbonylthio)pentanoic acid, and 2-cyano-2-propyl benzodithioate.

Specific examples of trithiocarbonate compounds include S-(2-cyano-2-propyl)-S-dodecyl trithiocarbonate, 4-cyano-4-[(dodecylsulfanyl-thiocarbonyl)sulfanyl]pentanoic acid, cyanomethyl dodecyl trithiocarbonate, and 2-(dodecylthiocarbonothiolthio)-2-methylpropionic acid.

Specific examples of dithiocarbamate compounds include cyanomethylmethyl(phenyl)carbamodithioate and cyanomethyldiphenylcarbamo-dithioate.

Specific examples of xanthate compounds include xanthogenate esters.

- Aromatic α-methylalkenyl dimer -
An example of the aromatic α-methylalkenyl dimer is 2,4-diphenyl-4-methyl-1-pentene.

Furthermore, as a chain transfer agent, a trithiocarbonate compound such as that used as a RAFT agent in reversible addition-fragmentation chain transfer (RAFT) polymerization, which is a type of living polymerization, can also be preferably used.

The molecular weight of the chain transfer agent is preferably 200 or more, since this can suppress contamination of the apparatus due to sublimation. The upper limit is preferably 1,000 or less, more preferably 800 or less, and even more preferably 600 or less, since this can increase the SH valence per unit mass.

From the viewpoint of adhesion, the content of the chain transfer agent is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass, and even more preferably 0.05% by mass to 1% by mass, based on the total solid content of the curable composition. Only one type of chain transfer agent may be used, or two or more types may be used in combination.

<Polyalkyleneimine>
The curable composition of the present disclosure may also contain a polyalkyleneimine. The polyalkyleneimine is used, for example, as a dispersing aid for pigments. The dispersing aid is a material for enhancing the dispersibility of the pigment in the curable composition. The polyalkyleneimine is a polymer obtained by ring-opening polymerization of an alkyleneimine, and is a polymer having at least a secondary amino group. The polyalkyleneimine may contain a primary amino group or a tertiary amino group in addition to the secondary amino group. The polyalkyleneimine is preferably a polymer having a branched structure containing a primary amino group, a secondary amino group, and a tertiary amino group. The number of carbon atoms of the alkyleneimine is preferably 2 to 6, more preferably 2 to 4, even more preferably 2 or 3, and particularly preferably 2.

The molecular weight of the polyalkyleneimine is preferably 200 or more, more preferably 250 or more. The upper limit is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 10,000 or less, and particularly preferably 2,000 or less. In addition, when the value of the molecular weight of the polyalkyleneimine can be calculated from the structural formula, the molecular weight of the polyalkyleneimine is the value calculated from the structural formula. On the other hand, when the molecular weight of the polyalkyleneimine cannot be calculated from the structural formula or is difficult to calculate, the value of the number average molecular weight measured by the boiling point elevation method is used. In addition,
When the boiling point elevation method is not possible or difficult to measure, the number average molecular weight measured by the viscosity method is used. When the boiling point elevation method is not possible or difficult to measure, the number average molecular weight measured by the viscosity method is used in terms of polystyrene as measured by GPC (gel permeation chromatography).

The amine value of the polyalkyleneimine is preferably 5 mmol/g or more, more preferably 10 mmol/g or more, and even more preferably 15 mmol/g or more.

Specific examples of alkyleneimines include ethyleneimine, propyleneimine, 1,2-butyleneimine, and 2,3-butyleneimine, with ethyleneimine or propyleneimine being preferred, and ethyleneimine being more preferred. The polyalkyleneimine is particularly preferably polyethyleneimine. Furthermore, the polyethyleneimine preferably contains primary amino groups in an amount of 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more, based on the total of the primary amino groups, secondary amino groups, and tertiary amino groups. Commercially available polyethyleneimines include Epomin SP-003, SP-006, SP-012, SP-018, SP-200, and P-1000 (all manufactured by Nippon Shokubai Co., Ltd.).

The content of the polyalkyleneimine in the total solid content of the curable composition is preferably 0.1% by mass to 5% by mass. The lower limit is more preferably 0.2% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. The upper limit is more preferably 4.5% by mass or less, even more preferably 4% by mass or less, and particularly preferably 3% by mass or less. The content of the polyalkyleneimine is preferably 0.5 parts by mass to 20 parts by mass relative to 100 parts by mass of the pigment. The lower limit is more preferably 0.6 parts by mass or more, even more preferably 1 part by mass or more, and particularly preferably 2 parts by mass or more. The upper limit is more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less. Only one type of polyalkyleneimine may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount thereof is within the above range.

<Curing accelerator>
The curable composition of the present disclosure may contain a curing accelerator. Examples of the curing accelerator include thiol compounds, methylol compounds, amine compounds, phosphonium salt compounds, amidine salt compounds, amide compounds, base generators, isocyanate compounds, alkoxysilane compounds, and onium salt compounds. Specific examples of the curing accelerator include the compounds described in paragraph 0164 of WO 2022/085485. The content of the curing accelerator in the total solid content of the curable composition is preferably 0.3% by mass to 8.9% by mass, more preferably 0.8% by mass to 6.4% by mass.

<Infrared absorbent>
The curable composition of the present disclosure may contain an infrared absorbing agent. For example, when an infrared transmission filter is formed using the curable composition of the present disclosure, the wavelength of light transmitted through the film obtained by containing an infrared absorbing agent in the curable composition can be shifted to a longer wavelength side. The infrared absorbing agent is preferably a compound having a maximum absorption wavelength on the longer wavelength side than a wavelength of 700 nm. The infrared absorbing agent is preferably a compound having a maximum absorption wavelength in the range of more than 700 nm and not more than 1800 nm. In addition, the ratio A ¹ /A ² between the absorbance A ¹ at a wavelength of 500 nm of the infrared absorbing agent and the absorbance A ² at the maximum absorption wavelength is preferably 0.08 or less, more preferably 0.04 or less.

Infrared absorbers include pyrrolopyrrole compounds, cyanine compounds, squarylium compounds, phthalocyanine compounds, naphthalocyanine compounds, quaterrylene compounds, merocyanine compounds, croconium compounds, oxonol compounds, iminium compounds, dithiol compounds, triarylmethane compounds, pyrromethene compounds, azomethine compounds, anthraquinone compounds, dibenzofuranone compounds, dithiolene metal complexes, metal oxides, metal borides, etc. Specifically, the compounds described in paragraphs 0114 to 0121 of WO 2022/065215, the compounds described in paragraphs 0144 to 0146 of WO 2021/049441, the croconic acid compounds described in JP 2021-195515 A, the near-infrared absorbing dyes described in JP 2022-022070 A, and the croconium compounds described in WO 2019/021767 A can also be used.

The content of the infrared absorber in the total solid content of the curable composition is preferably 1% by mass to 40% by mass. The lower limit is more preferably 2% by mass or more, even more preferably 5% by mass or more, and particularly preferably 10% by mass or more. The upper limit is more preferably 30% by mass or less, and even more preferably 25% by mass or less. The curable composition of the present disclosure may contain only one type of infrared absorber, or may contain two or more types. When two or more types of infrared absorbers are contained, it is preferable that the total amount thereof is in the above range.

<Ultraviolet absorbing agent>
The curable composition of the present disclosure may contain an ultraviolet absorber. Examples of ultraviolet absorbers include conjugated diene compounds, aminodiene compounds, salicylate compounds, benzophenone compounds, benzotriazole compounds, acrylonitrile compounds, hydroxyphenyltriazine compounds, indole compounds, and triazine compounds. Specific examples of such compounds include the compounds described in paragraph 0179 of International Publication No. WO 2022/085485. As the ultraviolet absorber, the reactive triazine ultraviolet absorber described in JP 2021-178918 A and the ultraviolet absorber described in JP 2022-007884 A can be used. The content of the ultraviolet absorber in the total solid content of the curable composition is preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 5% by mass. Only one type of ultraviolet absorber may be used, or two or more types may be used. When two or more types are used, it is preferable that the total amount thereof is within the above range.

<Polymerization inhibitor>
The curable composition of the present disclosure may contain a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinone, p-methoxyphenol, di-tert-butyl-p-cresol, pyrogallol, tert-butylcatechol, benzoquinone, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), and N-nitrosophenylhydroxyamine salts (ammonium salts, cerous salts, etc.). Among these, p-methoxyphenol is preferred. The content of the polymerization inhibitor in the total solid content of the curable composition is preferably 0.0001% by mass to 5% by mass. The polymerization inhibitor may be one type or two or more types. In the case of two or more types, it is preferable that the total amount thereof is within the above range.

<Silane coupling agent>
The curable composition of the present disclosure may contain a silane coupling agent. In the present disclosure, the silane coupling agent refers to a silane compound having a hydrolyzable group and other functional groups. The hydrolyzable group refers to a substituent that is directly bonded to a silicon atom and can generate a siloxane bond by at least one of a hydrolysis reaction and a condensation reaction. Examples of the hydrolyzable group include a halogen atom, an alkoxy group, and an acyloxy group, and an alkoxy group is preferred. That is, the silane coupling agent is preferably a compound having an alkoxysilyl group. Examples of functional groups other than the hydrolyzable group include a vinyl group, a (meth)allyl group, a (meth)acryloyl group, a mercapto group, an epoxy group, an oxetane group, an amino group, a ureido group, a sulfide group, an isocyanate group, and a phenyl group, and an amino group, a (meth)acryloyl group, and an epoxy group are preferred. Specific examples of the silane coupling agent include the compounds described in paragraph 0177 of International Publication No. WO 2022/085485. The content of the silane coupling agent in the total solid content of the curable composition is preferably from 0.01% by mass to 15.0% by mass, and more preferably from 0.05% by mass to 10.0% by mass.
The silane coupling agent may be one type or two or more types. When two or more types are used, the total amount thereof is preferably within the above range.

<Surfactant>
The curable composition of the present disclosure may contain a surfactant. As the surfactant, various surfactants such as fluorine-based surfactants, nonionic surfactants, cationic surfactants, anionic surfactants, and silicone-based surfactants may be used. The surfactant is preferably a silicone-based surfactant or a fluorine-based surfactant. For the surfactant, reference may be made to the surfactants described in paragraphs 0238 to 0245 of WO 2015/166779, the contents of which are incorporated herein by reference.

The fluorine content in the fluorosurfactant is preferably 3% to 40% by mass, more preferably 5% to 30% by mass, and particularly preferably 7% to 25% by mass. Fluorine surfactants with a fluorine content within this range are effective in terms of uniformity of the coating film thickness and liquid saving, and also have good solubility in the curable composition.

As fluorosurfactants, compounds described in paragraphs 0167 to 0173 of WO 2022/085485 and fluorine-containing copolymers described in JP 2022-000494 can also be used.

As a nonionic surfactant, the compounds described in paragraph 0174 of WO 2022/085485 can also be used.

Silicone surfactants include DOWSIL SH8400, SH8400 FLUID, FZ-2122, 67 Additive, 74 Additive, M Additive, SF 8419 OIL (all manufactured by Dow Toray Co., Ltd.), TSF-4300, TSF-4445, TSF-4460, and TSF-4452 (all manufactured by Momen Co., Ltd.). Examples include BYK-307, BYK-322, BYK-323, BYK-330, BYK-333, BYK-3760, and BYK-UV3510 (manufactured by BYK-Chemie), etc.

　Also, the silicone surfactant may be a compound with the following structure, where n is 1 to 200.

The content of the surfactant in the total solid content of the curable composition is preferably 0.001% by mass to 5.0% by mass, and more preferably 0.005% by mass to 3.0% by mass. The surfactant may be one type or two or more types. When two or more types are used, the total amount thereof is preferably within the above range.

<Antioxidants>
The curable composition of the present disclosure may contain an antioxidant. Examples of the antioxidant include phenolic compounds, phosphite compounds, and thioether compounds. As the phenolic compound, any phenolic compound known as a phenolic antioxidant may be used. A preferred phenolic compound is a hindered phenolic compound. A compound having a substituent at the site (ortho position) adjacent to the phenolic hydroxy group is preferred. As the above-mentioned substituent, a substituted or unsubstituted alkyl group having 1 to 22 carbon atoms is preferred. In addition, the antioxidant is also preferably a compound having a phenolic group and a phosphite group in the same molecule. In addition, a phosphorus-based antioxidant may also be suitably used as the antioxidant. Examples of phosphorus-based antioxidants include tris[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine, tris[2-[(4,6,9,11-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-2-yl)oxy]ethyl]amine, and ethylbis(2,4-di-tert-butyl-6-methylphenyl)phosphite. Commercially available antioxidants include, for example, Adeka STAB AO-20, Adeka STAB AO-30, Adeka STAB AO-40, Adeka STAB AO-50, Adeka STAB AO-50F, Adeka STAB AO-60, Adeka STAB AO-60G, Adeka STAB AO-80, and Adeka STAB AO-330 (manufactured by ADEKA Corporation). In addition, the antioxidant may be a compound described in paragraphs 0023 to 0048 of Japanese Patent No. 6268967, a compound described in International Publication No. WO 2017/006600, a compound described in International Publication No. WO 2017/164024, or a compound described in Korean Patent Publication No. 10-2019-0059371. The content of the antioxidant in the total solid content of the curable composition is preferably 0.01% by mass to 20% by mass, and more preferably 0.3% by mass to 15% by mass. Only one type of antioxidant may be used, or two or more types may be used. When two or more types are used, the total amount thereof is preferably within the above range.

<Other ingredients>
The curable composition of the present disclosure may contain, as necessary, a sensitizer, a curing accelerator, a filler, a heat curing accelerator, a plasticizer, and other auxiliaries (e.g., conductive particles, defoamers, flame retardants, leveling agents, peeling accelerators, fragrances, surface tension adjusters, etc.). By appropriately incorporating these components, properties such as film properties can be adjusted. As these components, the compounds described in paragraph 0182 of WO 2022/085485, the xanthene type epoxy resins described in JP 2021-195421 A, the xanthene type epoxy resins described in JP 2021-195422 A, and the like can also be used.

The curable composition of the present disclosure may contain a metal oxide to adjust the refractive index of the resulting film. Examples of the metal oxide include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , and SiO ₂ . The primary particle size of the metal oxide is preferably 1 nm to 100 nm, more preferably 3 nm to 70 nm, and even more preferably 5 nm to 50 nm. The metal oxide may have a core-shell structure. In this case, the core may be hollow.

The curable composition of the present disclosure may contain a light resistance improver. The light resistance improver may be the compound described in paragraph 0183 of WO 2022/085485.

It is also preferred that the curable composition of the present disclosure is substantially free of terephthalic acid ester. Here, "substantially free" means that the content of terephthalic acid ester in the total amount of the curable composition is 1000 ppb by mass or less, more preferably 100 ppb by mass or less, and particularly preferably 0 (zero).

The curable composition of the present disclosure preferably has a low melamine content. Specifically, the melamine content is preferably 10,000 mass ppm or less in the total amount of the curable composition, and may be 0 (zero).

From the viewpoint of environmental regulations, the use of perfluoroalkylsulfonic acid and its salts, and perfluoroalkylcarboxylic acid and its salts may be restricted. When the content of the above-mentioned compounds is reduced in the curable composition of the present disclosure, the content of perfluoroalkylsulfonic acid (particularly perfluoroalkylsulfonic acid having 6 to 8 carbon atoms in the perfluoroalkyl group) and its salts, and perfluoroalkylcarboxylic acid (particularly perfluoroalkylcarboxylic acid having 6 to 8 carbon atoms in the perfluoroalkyl group) and its salts is preferably in the range of 0.01 ppb to 1,000 ppb, more preferably in the range of 0.05 ppb to 500 ppb, and even more preferably in the range of 0.1 ppb to 300 ppb, based on the total solid content of the curable composition. The curable composition of the present disclosure may be substantially free of perfluoroalkylsulfonic acid and its salts, and perfluoroalkylcarboxylic acid and its salts. For example, by using a compound that can be a substitute for perfluoroalkylsulfonic acid and its salt, and a compound that can be a substitute for perfluoroalkyl carboxylic acid and its salt, a curable composition that is substantially free of perfluoroalkylsulfonic acid and its salt, and perfluoroalkyl carboxylic acid and its salt may be selected. Examples of compounds that can be a substitute for regulated compounds include compounds that are excluded from the scope of regulation due to the difference in the number of carbon atoms in the perfluoroalkyl group. However, the above content does not prevent the use of perfluoroalkylsulfonic acid and its salt, and perfluoroalkyl carboxylic acid and its salt. The curable composition of the present disclosure may contain perfluoroalkylsulfonic acid and its salt, and perfluoroalkyl carboxylic acid and its salt within the maximum allowable range.

The moisture content of the curable composition of the present disclosure is preferably 3% by mass or less, more preferably 0.01% by mass to 1.5% by mass, and even more preferably in the range of 0.1% by mass to 1.0% by mass. The moisture content can be measured by the Karl Fischer method.

The curable composition of the present disclosure can be used by adjusting the viscosity for the purpose of adjusting the film surface state (flatness, etc.), adjusting the film thickness, etc. The value of the viscosity can be appropriately selected as needed, and is preferably, for example, 0.3 mPa·s to 50 mPa·s, and more preferably 0.5 mPa·s to 20 mPa·s at 25° C. The viscosity can be measured, for example, using a cone-plate type viscometer, with the temperature adjusted to 25° C.
From the viewpoints of environmental friendliness, suppression of foreign matter generation, and suppression of equipment contamination, the amount of chloride ions in the curable composition of the present disclosure is preferably 10,000 ppm or less, more preferably 1000 ppm or less. In order to make the chloride ions in the curable composition fall within the above range, a raw material with a low chloride ion content may be used, and a method of removing chloride ions by washing with water, ion exchange resin, filter filtration, etc. Known methods may be used to measure chloride ions, and examples of such methods include ion chromatography and combustion ion chromatography.

(Storage container)
The container for storing the curable composition is not particularly limited, and a known container can be used. In addition, the container described in paragraph 0187 of WO 2022/085485 can also be used as the container.

(Method of preparing the curable composition)
The curable composition of the present disclosure can be prepared by mixing the above-mentioned components. When preparing the curable composition, all components may be simultaneously dissolved and/or dispersed in a solvent to prepare the curable composition, or, if necessary, each component may be appropriately prepared as two or more solutions or dispersions, which are mixed at the time of use (at the time of application) to prepare the curable composition.

In addition, when preparing the curable composition, it is preferable to include a process for dispersing the pigment. In the process for dispersing the pigment, mechanical forces used to disperse the pigment include compression, squeezing, impact, shear, and cavitation. Specific examples of these processes include bead mills, sand mills, roll mills, ball mills, paint shakers, microfluidizers, high-speed impellers, sand grinders, flow jet mixers, high-pressure wet atomization, and ultrasonic dispersion. In addition, when grinding the pigment in a sand mill (bead mill), it is preferable to use beads with a small diameter and increase the bead packing rate, thereby increasing the grinding efficiency. In addition, it is preferable to remove coarse particles by filtration, centrifugation, or the like after the grinding process. In addition, the process and dispersing machine for dispersing the pigment may be suitably used as described in "Dispersion Technology Encyclopedia, published by Information System Co., Ltd., July 15, 2005" or "Dispersion Technology and Industrial Application Practice Focusing on Suspension (Solid/Liquid Dispersion System) - Comprehensive Data Collection, published by Management Development Center Publishing Department, October 10, 1978", and in paragraph number 0022 of JP2015-157893A. In addition, in the process for dispersing the pigment, a salt milling process may be performed to refine the particles. For the materials, equipment, processing conditions, etc. used in the salt milling process, the descriptions in, for example, JP2015-194521A and JP2012-046629A may be referred to. As beads used for dispersion, zirconia, agate, quartz, titania, tungsten carbide, silicon nitride, alumina, stainless steel, glass, or a combination thereof may be used. In addition, inorganic compounds with a Mohs hardness of 2 or more can be used. The composition may contain 1 to 10,000 ppm of the above beads.

When preparing the curable composition, it is preferable to filter the curable composition with a filter for the purpose of removing foreign matter and reducing defects. The filters and filtration methods described in paragraphs 0196 to 0199 of WO 2022/085485 can also be used.

The curable composition of the present disclosure is preferably used for exposure using an excimer laser with a wavelength of 150 nm to 300 nm.

(Cured product, film)
The film of the present disclosure is a cured product obtained by curing the curable composition of the present disclosure described above. The film of the present disclosure is an example of a cured product obtained by curing the curable composition of the present disclosure. The film of the present disclosure can be used in optical filters such as color filters and infrared transmission filters. The film of the present disclosure can be preferably used as a color pixel of a color filter. Examples of the color pixel include a red pixel, a green pixel, a blue pixel, a magenta pixel, a cyan pixel, and a yellow pixel, and the like. The color pixel is preferably a green pixel or a blue pixel, and more preferably a green pixel.

The thickness (film thickness) of the film of the present disclosure may be adjusted as appropriate depending on the purpose, and is preferably 0.1 μm to 20 μm. The upper limit of the film thickness is more preferably 10 μm or less, even more preferably 5 μm or less, particularly preferably 3 μm or less, and most preferably 1.5 μm or less. The lower limit of the film thickness is more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.

(Method for producing the cured product)
The method for producing the cured product of the present disclosure comprises applying a light having a wavelength of 150 nm to 300 nm to the curable composition of the present disclosure.
In the case of producing a film as an example of a cured product, the method for producing a film includes a step of irradiating the curable composition of the present disclosure described above with excimer laser light having a wavelength of 150 nm to 300 nm.

Examples of light with a wavelength of 150 nm to 300 nm include KrF radiation (wavelength 248 nm) and ArF radiation (wavelength 193 nm).
Moreover, the light having a wavelength of 150 nm to 300 nm is preferably an excimer laser.
The shape of the resulting cured product is not particularly limited, but is preferably a film.

The film according to the present disclosure can be produced through a process of applying the curable composition according to the present disclosure to a support. The film production method preferably further includes a process of forming a pattern (pixels). Methods for forming the pattern (pixels) include photolithography and dry etching, with photolithography being preferred.

Pattern formation by photolithography preferably includes a step of forming a curable composition layer on a support using the curable composition of the present disclosure, a step of exposing the curable composition layer in a pattern, and a step of developing and removing the unexposed parts of the curable composition layer to form a pattern (pixels). If necessary, a step of baking the curable composition layer (pre-bake step) and a step of baking the developed pattern (pixels) (post-bake step) may be provided.

In the step of forming the curable composition layer, the curable composition layer is formed on a support using the curable composition of the present disclosure. The support is not particularly limited and can be appropriately selected depending on the application. For example, a glass substrate, a silicon substrate, etc. can be mentioned, and a silicon substrate is preferable. A charge-coupled device (CCD), a complementary metal oxide semiconductor (CMOS), a transparent conductive film, etc. may be formed on the silicon substrate. A black matrix for isolating each pixel may be formed on the silicon substrate. A base layer may be provided on the silicon substrate to improve adhesion with the upper layer, prevent diffusion of substances, or flatten the substrate surface. The base layer may be formed using a composition obtained by removing the coloring material from the curable composition described in this specification, or a composition containing the resin, polymerizable compound, surfactant, etc. described in this specification. The surface contact angle of the base layer is preferably 20° to 70° when measured with diiodomethane. It is also preferable that the surface contact angle is 30° to 80° when measured with water.

　A known method can be used to apply the curable composition. For example, the method described in paragraph 0207 of WO 2022/085485 can be used.

The curable composition layer formed on the support may be dried (prebaked). When a film is produced by a low-temperature process, prebaking may not be performed. When prebaking is performed, the prebaking temperature is preferably 150°C or less, more preferably 120°C or less, and even more preferably 110°C or less. The lower limit can be, for example, 50°C or more, and can also be 80°C or more. The prebaking time is preferably 10 seconds to 300 seconds, more preferably 40 seconds to 250 seconds, and even more preferably 80 seconds to 220 seconds. Prebaking can be performed using a hot plate, an oven, etc.

Next, the curable composition layer is exposed to light in a pattern (exposure step). For example, the curable composition layer can be exposed to light in a pattern by using a stepper exposure machine or a scanner exposure machine through a mask having a predetermined mask pattern. This allows the exposed parts to be cured.

Examples of radiation (light) that can be used for exposure include g-line and i-line. Light having a wavelength of 300 nm or less (preferably light having a wavelength of 150 nm to 300 nm) can also be used. Examples of light having a wavelength of 300 nm or less include KrF line (wavelength 248 nm) and ArF line (wavelength 193 nm), with KrF line (wavelength 248 nm) being preferred. A long-wavelength light source of 300 nm or more can also be used.

In addition, during exposure, light may be applied continuously or in pulses (pulse exposure). Pulse exposure is an exposure method in which light is applied and paused repeatedly in short cycles (e.g., milliseconds or less).

The irradiation amount (exposure amount) is, for example, preferably 0.03 J/cm ² to 2.5 J/cm ² , more preferably 0.05 J/cm ² to 1.0 J/cm ^2. The oxygen concentration during exposure can be appropriately selected, and in addition to being performed under air, for example, exposure may be performed under a low-oxygen atmosphere with an oxygen concentration of 19 volume% or less (e.g., 15 volume%, 5 volume%, or substantially oxygen-free), or exposure may be performed under a high-oxygen atmosphere with an oxygen concentration of more than 21 volume% (e.g., 22 volume%, 30 volume%, or 50 volume%). The exposure illuminance can be appropriately set, and can usually be selected from the range of 1000 W/m ² to 100,000 W/m ² (e.g., 5000 W/m ² , 15000 W/m ² , or 35000 W/m ² ). The oxygen concentration and exposure illuminance may be appropriately combined. For example, an oxygen concentration of 10% by volume and an illuminance of 10,000 W/m ² , and an oxygen concentration of 35% by volume and an illuminance of 20,000 W/m ² , can be used.

Next, the unexposed parts of the curable composition layer are developed and removed to form a pattern (pixels). The unexposed parts of the curable composition layer can be developed and removed using a developer. As a result, the unexposed parts of the curable composition layer in the exposure step are dissolved into the developer, and only the photocured parts remain. The temperature of the developer is preferably, for example, 20°C to 30°C. The development time is preferably 20 seconds to 180 seconds. In order to improve residue removal, the process of shaking off the developer every 60 seconds and then supplying new developer may be repeated several times.

The developer may be an organic solvent or an alkaline developer, with an alkaline developer being preferred. The developer and development method described in paragraph 0214 of WO 2022/085485 may also be used.

After development and drying, it is preferable to perform additional exposure processing or heating processing (post-baking). Additional exposure processing and post-baking are curing processing after development to complete curing. The heating temperature in post-baking is, for example, preferably 100°C to 240°C, more preferably 200°C to 240°C. Post-baking can be performed continuously or batchwise using a heating means such as a hot plate, a convection oven (hot air circulation dryer), or a high-frequency heater to achieve the above conditions for the developed film. When additional exposure processing is performed, it is preferable that the light used for exposure has a wavelength of 400 nm or less. In addition, additional exposure processing may be performed by the method described in Korean Patent Publication No. 10-2017-0122130.

　The pattern formation by dry etching can also be performed using the method described in paragraph 0216 of WO 2022/085485.

(Optical elements)
The optical element of the present disclosure includes the film of the present disclosure described above.
The optical element according to the present disclosure has the film according to the present disclosure.
Examples of the optical element include an optical filter, a lens, a prism, a reflecting mirror, a diffraction grating, etc. Among these, an optical filter is preferable.
The types of optical filters include color filters and infrared transmission filters, and are preferably color filters. The color filter preferably has the film according to the present disclosure as its colored pixels.

The film thickness of the film disclosed herein in an optical filter can be adjusted as appropriate depending on the purpose. The film thickness is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. The lower limit of the film thickness is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.

The width of the pixels included in the optical filter is preferably 0.4 μm to 10.0 μm. The lower limit is more preferably 0.4 μm or more, even more preferably 0.5 μm or more, and particularly preferably 0.6 μm or more. The upper limit is more preferably 5.0 μm or less, even more preferably 2.0 μm or less, particularly preferably 1.0 μm or less, and most preferably 0.8 μm or less. The Young's modulus of the pixels is preferably 0.5 GPa to 20 GPa, and more preferably 2.5 GPa to 15 GPa.

Each pixel included in the optical filter preferably has high flatness. Specifically, the surface roughness Ra of the pixel is preferably 100 nm or less, more preferably 40 nm or less, and even more preferably 15 nm or less. Although the lower limit is not specified, it is preferably 0.1 nm or more, for example. The surface roughness of the pixel can be measured using, for example, an AFM (atomic force microscope) Dimension 3100 manufactured by Veeco. In addition, the contact angle of water on the pixel can be set to an appropriate preferred value, but is typically in the range of 50° to 110°. The contact angle can be measured using, for example, a contact angle meter CV-DT-A type (manufactured by Kyowa Interface Science Co., Ltd.). In addition, it is preferable that the volume resistance value of the pixel is high. Specifically, the volume resistance value of the pixel is preferably 10 ⁹ Ω·cm or more, more preferably 10 ¹¹ Ω·cm or more. Although the upper limit is not specified, it is preferably 10 ¹⁴ Ω·cm or less, for example. The volume resistance value of the pixel can be measured using an ultra-high resistance meter 5410 (manufactured by Advantest Corporation).

In the optical filter, a protective layer may be provided on the surface of the film according to the present disclosure. By providing a protective layer, various functions such as oxygen blocking, low reflection, hydrophilicity/hydrophobicity, and shielding of light of a specific wavelength (ultraviolet rays, near infrared rays, etc.) can be imparted. The thickness of the protective layer is preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 5 μm. Methods for forming the protective layer include a method of forming the protective layer by applying a composition for forming the protective layer, a chemical vapor deposition method, and a method of attaching a molded resin with an adhesive. The components constituting the protective layer include (meth)acrylic resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyphenylene resin, polyarylene ether phosphine oxide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyester resin, styrene resin, polyol resin, polyvinylidene chloride resin, melamine resin, urethane resin, aramid resin, polyamide resin, alkyd resin, epoxy resin, modified silicone resin, fluorine resin, polycarbonate resin, polyacrylonitrile resin, cellulose resin, Si, C, W, Al ₂ O ₃ , Mo, SiO ₂ , Si ₂ N ₄ , etc., and may contain two or more of these components. For example, in the case of a protective layer intended for oxygen blocking, the protective layer preferably contains a polyol resin, SiO ₂ , and Si ₂ N ₄ . In the case of a protective layer intended to reduce reflection, the protective layer preferably contains a (meth)acrylic resin and a fluorine resin.

The protective layer may contain additives such as organic/inorganic particles, absorbents for light of a specific wavelength (e.g., ultraviolet light, near infrared light, etc.), refractive index adjusters, antioxidants, adhesives, and surfactants, as necessary. Examples of organic/inorganic particles include polymer particles (e.g., silicone resin fine particles, polystyrene fine particles, melamine resin fine particles), titanium oxide, zinc oxide, zirconium oxide, indium oxide, aluminum oxide, titanium nitride, titanium oxynitride, magnesium fluoride, hollow silica, silica, calcium carbonate, and barium sulfate. Known absorbents can be used as absorbents for light of a specific wavelength. The content of these additives can be appropriately adjusted, but is preferably 0.1% by mass to 70% by mass, and more preferably 1% by mass to 60% by mass, based on the total mass of the protective layer.

The protective layer may also be the one described in paragraphs 0073 to 0092 of JP2017-151176A.

The optical filter may have a structure in which each pixel is embedded in a space partitioned by partitions, for example in a grid pattern.

(Image sensor, solid-state imaging device, and image display device)
The image sensor, solid-state imaging device, and image display device of the present disclosure all include the film of the present disclosure.
An image sensor according to the present disclosure comprises a membrane according to the present disclosure.
Examples of the image sensor include a solid-state imaging element, an X-ray imaging element, an organic thin-film imaging element, etc. Among these, the present invention can be suitably used for a solid-state imaging element.
The solid-state imaging device according to the present disclosure includes the film according to the present disclosure. The configuration of the solid-state imaging device is not particularly limited as long as it functions as a solid-state imaging device, and examples thereof include the following configurations.

The configuration has a plurality of photodiodes constituting a light receiving area of a solid-state imaging element (such as a CCD (charge-coupled device) image sensor or a CMOS (complementary metal-oxide semiconductor) image sensor) on a substrate, a light-shielding film on the photodiodes and the transfer electrodes with only the light receiving parts of the photodiodes open, a device protection film made of silicon nitride or the like formed on the light-shielding film so as to cover the entire light-shielding film and the light receiving parts of the photodiodes, and a color filter on the device protection film.Furthermore, the configuration may have a light-collecting means (e.g., a microlens, etc., the same below) on the device protection film and below the color filter (on the side closer to the substrate), or a configuration may have a light-collecting means on the color filter.
The color filter may have a structure in which each colored pixel is embedded in a space partitioned, for example, in a lattice shape, by partitions. In this case, the partitions preferably have a lower refractive index than each colored pixel. Examples of imaging devices having such a structure include those described in JP 2012-227478 A, JP 2014-179577 A, and WO 2018/043654 A. In addition, as shown in JP 2019-211559 A, an ultraviolet absorbing layer may be provided in the structure of the solid-state imaging element to improve light resistance. The imaging device including the solid-state imaging element according to the present disclosure can be used for digital cameras, electronic devices having an imaging function (such as mobile phones), as well as vehicle-mounted cameras and surveillance cameras.

The image display device according to the present disclosure includes the film according to the present disclosure. Examples of image display devices include liquid crystal display devices and organic electroluminescence display devices. Definitions of image display devices and details of each image display device are described, for example, in "Electronic Display Devices" (written by Sasaki Akio, published by Kogyo Chosakai Co., Ltd. in 1990) and "Display Devices" (written by Ibuki Yoshiaki, published by Sangyo Tosho Co., Ltd. in 1989). Liquid crystal display devices are described, for example, in "Next Generation Liquid Crystal Display Technology" (edited by Uchida Tatsuo, published by Kogyo Chosakai Co., Ltd. in 1994). There are no particular limitations on the liquid crystal display devices to which the present disclosure can be applied, and the present disclosure can be applied, for example, to the various types of liquid crystal display devices described in the above "Next Generation Liquid Crystal Display Technology."

(Radical Polymerization Initiator)
The radical polymerization initiator of the present disclosure is represented by formula (3). The radical polymerization initiator represented by formula (3) has a dimer structure and a bulky branched alkyl group, and therefore has high sensitivity, excellent cross-sectional rectangularity when patterned, and excellent hydrolysis resistance. Therefore, it can exist stably over time.

In formula (3), X, _R21 , _R22 , n1 and n2 are the same as X, _R21 , _R22 , n1 and n2 in formula (1), and preferred embodiments are also the same. In addition, _Rx1 , _Rx2 and _Rx3 in formula (3) are the same as _Rx1 , _Rx2 and _Rx3 in formula (4), and preferred embodiments are also the same.

The compound represented by formula (3) can be synthesized, for example, according to or with reference to the synthesis method for oxime ester compounds described in WO 2015/152153. An example of a synthesis method for a radical polymerization initiator represented by formula (3) is shown in the Examples section below.

The present disclosure will be described more specifically below with reference to examples.
The materials, amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of this disclosure. The scope of this disclosure is not limited to the specific examples shown below. In the examples, "%" and "parts" mean "mass %" and "mass parts", respectively, unless otherwise specified.

Polymerization initiators (A) A-1 to 138 and 141 to 165 in the examples are the same compounds as specific examples A-1 to 138 and 141 to 165 of the radical polymerization initiator represented by the above formula (1), respectively. The groups represented by R ^x1 to R ^x9 and L in X in each compound are as follows: R ^x1 : phenyl group, R ^x2 : ethyl group, R ^x3 : methyl group, R ^x4 : methyl group, R ^x5 : n-propyl group, R ^x6 : n-propyl group, R ^x7 : methyl group, R ^x8 : methyl group, R ^x9 : methyl group, and L: phenylene.

<Synthesis Example 1>: Synthesis of radical polymerization initiator A-153

58.6 g of N-ethylcarbazole was added to the flask and dissolved in 200 mL of chlorobenzene. This was cooled to 5°C and 40.8 g of aluminum chloride was added. With stirring, 28.3 g of propionyl chloride was added dropwise over 30 minutes, the mixture was returned to room temperature and stirred for a further 2 hours. The resulting reaction solution was cooled again to 5°C and 42.0 g of aluminum chloride was added. With stirring, 29.1 g of propionyl chloride was added dropwise over 30 minutes, the mixture was returned to room temperature and stirred for a further 2 hours. The resulting reaction solution was quenched with ice water and extracted with ethyl acetate, after which the organic layer was concentrated. Methanol was added to the concentrate and the precipitated crystals were filtered off to obtain A-153-a.

Next, 21.5 g of A-153-a was dissolved in 100 mL of tetrahydrofuran and 100 mL of methanol, and 6.7 g of sodium hydroxide was added and stirred at room temperature for 1 hour. This was cooled to 5°C, and 19.8 g of isoamyl nitrite was added dropwise over 30 minutes. The resulting reaction solution was extracted with ethyl acetate, washed with water, and the organic layer was concentrated. The concentrate was purified by silica gel column chromatography (hexane/ethyl acetate = 8/1), and the precipitated crystals were filtered off to obtain A-153-b.

2.9 g of A-153-b was dissolved in 50 mL of tetrahydrofuran, and 1.9 g of pyridine was added. The mixture was cooled to 5°C, and 2.0 g of pivaloyl chloride was added and stirred at room temperature for 2 hours. The resulting reaction solution was extracted with ethyl acetate, washed with water, and the organic layer was concentrated. The concentrate was purified by silica gel column chromatography (hexane/ethyl acetate = 8/1), and the precipitated crystals were filtered off, yielding 2.1 g of A-153.

¹ HNMR (400MHz) δ = 1.27 (s, 12H), 1.36 (t, 3H), 2.34 (s, 3H), 4.51 (q, 2H), 7.79 (d, 2H ), 8.18 (d, 2H), 9.02 (s, 2H)

Synthesis Example 2: Synthesis of radical polymerization initiator A-126 1.2 g of A-126 was obtained in the same manner as in Synthesis Example 1, except that N-ethylcarbazole was replaced with dibenzothiophene.

¹ HNMR (400MHz) δ = 1.27 (s, 12H), 2.34 (s, 3H), , 7.82 (d, 2H), 8.18 (d, 2H), 8.38 (s, 2H)

Synthesis Example 3: Synthesis of radical polymerization initiator A-144 1.9 g of A-144 was obtained in the same manner as in Synthesis Example 1, except that N-ethylcarbazole was replaced with dibenzofuran.

¹ HNMR (400MHz) δ = 1.27 (s, 12H), 2.34 (s, 3H), 7.75 (d, 2H), 8.09 (d, 2H), 8.10 (s, 2H) )

Synthesis Example 4: Synthesis of radical polymerization initiator A-154 1.6 g of A-154 was obtained in the same manner as in Synthesis Example 1, except that pivaloyl chloride was replaced with 1-methyl-1-cyclopropylcarboxylic acid chloride.

¹ HNMR (400MHz) δ = 0.93 (m, 4H), 1.18 (m, 4H), 1.22 (s, 6H), 1.36 (t, 3H), 2.34 (s, 3H) ), 4.51 (q, 2H), 7.79 (d, 2H), 8.18 (d, 2H), 9.02 (s, 2H)

Synthesis Example 5: Synthesis of radical polymerization initiator A-156 2.2 g of A-156 was obtained in the same manner as in Synthesis Example 1, except that pivaloyl chloride was replaced with 1-adamantylcarboxylic acid chloride.

¹ HNMR (400MHz) δ = 1.36 (t, 3H), 1.5-2.1 (m, 30H), 2.34 (s, 3H), 4.51 (q, 2H), 7.79 (d, 2H), 8.18 (d, 2H), 9.02 (s, 2H)

Example 1: Preparation of red curable composition [Preparation of red pigment dispersion 1]
A mixture having the following composition was stirred and mixed uniformly, and then dispersed for 5 hours in an Eiger mill ("Mini Model M-250 MKII" manufactured by Eiger Japan Co., Ltd.) using zirconia beads having a diameter of 1 mm. The mixture was then filtered through a 5 μm filter to prepare red pigment dispersion 1.
<Composition>
Coloring material (equal mixture of C.I. Pigment Red 254, C.I. Pigment Red 272, and C.I. Pigment Red 139): 60.1 parts Pigment derivative (Syn-1): 10.2 parts Resin (B1) (C2-1) having a crosslinkable group and a graft chain: 20 parts Solvent (propylene glycol monomethyl ether acetate): 350 parts

[Preparation of Curable Composition]
The following components were mixed to prepare a red curable composition.
<Composition>
Red pigment dispersion 1: 440.3 parts Resin (alkali-soluble resin) (B-1): 5 parts Radical curable compound (C1-1) having a molecular weight of less than 3000: 7.0 parts Polymerization initiator (A) (radical polymerization initiator A-1 represented by formula (1)): 3.0 parts Epoxy compound (EHPE-3150, manufactured by Daicel Corporation): 0.02 parts Ultraviolet absorber (TINUVIN326, manufactured by BASF Corporation): 0.01 parts Surfactant (KF-6001 (polydimethylsiloxane modified with carbinol at both ends, manufactured by Shin-Etsu Chemical Co., Ltd.)): 0.01 parts by mass Polymerization inhibitor (p-methoxyphenol): 0.01 parts by mass Solvent (propylene glycol monomethyl ether acetate): 50 parts

<Examples 2 to 199 and Comparative Examples 1 to 3>
Pigment dispersions were prepared in the same manner as in Example 1 using the components as shown in Tables 1 to 8 below, and then curable compositions were prepared using the obtained pigment dispersions. Note that in Examples 2 to 55, red curable compositions were prepared, in Examples 56 to 114, green curable compositions were prepared, in Examples 115 to 164, blue curable compositions were prepared, in Examples 165 to 175, infrared (IR) absorbing curable compositions were prepared, and in Examples 176 to 199, black or white curable compositions were prepared.
In addition, although Tables 1 to 8 do not list the epoxy compound, ultraviolet absorber, surfactant, and polymerization inhibitor, the curable compositions of Examples 2 to 199 and Comparative Examples 1 to 3 contain the same epoxy compound, ultraviolet absorber, surfactant, and polymerization inhibitor as in Example 1 in the same amounts as in Example 1. When two or more coloring materials are contained, they are mixed in equal amounts.

Details of each component used in the above curable composition are as follows:

<Coloring material>
PR254: C.I. Pigment Red 254 [diketopyrrolopyrrole compound, red pigment (R pigment)]
PR272: C.I. Pigment Red 272 [diketopyrrolopyrrole compound, red pigment (R pigment)]
PR291: C.I. Pigment Red 291 [brominated diketopyrrolopyrrole compound, red pigment (R pigment)]
PR177: C.I. Pigment Red 177 [anthraquinone compound, red pigment (R pigment)]
PR264: C.I. Pigment Red 264 [diketopyrrolopyrrole compound, red pigment (R pigment)]
PG36: C.I. Pigment Green 36 [copper phthalocyanine complex, green pigment (G pigment)]
PG58: C.I. Pigment Green 58 [zinc phthalocyanine complex, green pigment (G pigment)]
PY129: C.I. Pigment Yellow 129 [azomethine copper complex, yellow pigment (Y pigment)]
PY138: C.I. Pigment Yellow 138 [quinophthalone compound, yellow pigment (Y pigment)]
PY139: C.I. Pigment Yellow 139 [isoindoline compound, yellow pigment (Y pigment)]
PY150: C.I. Pigment Yellow 150 [monoazo compound, yellow pigment (Y pigment)]
PY185: C.I. Pigment Yellow 185 [isoindoline compound, yellow pigment (Y pigment)]
PY215: C.I. Pigment Yellow 215 [Pritegin compound, yellow pigment (Y pigment)]
PB15:6: C.I. Pigment Blue 15:6 [copper phthalocyanine complex, blue pigment (B pigment)]
PV23: C.I. Pigment Violet 23 [dioxazine compound, purple pigment (B pigment)]

P-1: Compound with the following structure (diketopyrrolopyrrole boron complex, in the following structural formula, Me represents a methyl group and Ph represents a phenyl group)

P-2: Compound with the following structure (squarylium pigment)

P-3: Black pigment (Titanium Black (TiOxNy) manufactured by Mitsubishi Materials Corporation)
P-4: White pigment (titanium oxide (TTO-51(C)) manufactured by Ishihara Sangyo Kaisha)
P-5: Compound having the following structure (xanthene magenta dye)

<Pigment Derivatives>
Syn-1 to Syn-7: Compounds having the following structure

C2-1: Resin having the following structure (Mw 20,000, acid value 67 mgKOH/g)

C2-2: Resin having the following structure (Mw 23,000, acid value 59 mg KOH / g)

C2-3: Resin having the following structure (Mw 18,000, acid value 69 mg KOH / g)

C2-4: Resin with the following structure (numbers attached to the main chain are molar ratios. Mw 23,000, acid value 67 mg KOH/g)

C2-5: Resin with the following structure (Mw 10,000, acid value 85 mg KOH/g)

C2-6: Resin with the following structure (Mw 18,000, acid value 82 mg KOH/g)

C2-H1: Resin with the following structure that does not have a crosslinkable group (Mw 8,500, acid value 82 mgKOH/g)

<Solvent>
S-1: Propylene glycol monomethyl ether acetate (PGMEA)
S-2: Propylene glycol monomethyl ether (PGME)
S-3: Cyclopentanone S-4: 3-Methoxybutanol

<Resin>
B-1: Resin having the following structure (the numbers attached to the main chain are molar ratios; Mw 11,000, acid value 69 mgKOH/g)

B-2: Resin with the following structure (numbers attached to the main chain are molar ratios. Mw 21,000, double bond equivalent weight 470)

B-3: Resin with the following structure (numbers attached to the main chain are molar ratios. Mw 12,000, acid value 80 mg KOH/g)

<Radically curable compound (C1) having a molecular weight of less than 3,000>
C1-1 to C1-5: Compounds having the following structures

<Polymerization initiator to be used in combination>
a-1 to a-4: Compounds having the following structure

<Comparative Polymerization Initiator>
CA-1 to CA-2: Compounds having the following structures

<Thiol compounds>
T-1 to T-4: Compounds having the following structures

<Evaluation>
(sensitivity, rectangularity, hydrolysis resistance, storage stability)
Each of the curable compositions obtained in the above examples and comparative examples was applied by spin coating to the surface of the undercoat layer of an 8-inch (203.2 mm) silicon wafer with an undercoat layer so that the film thickness after application was 0.4 μm. Thereafter, the wafer was heated at 100° C. for 2 minutes using a hot plate to form a curable layer. Next, the obtained curable layer was exposed to light (KrF line) with a wavelength of 248 nm through a mask having a 0.5 μm square pattern using a KrF scanner exposure machine under irradiation conditions of illuminance 25000 W/m ² , pulse width 30 nanoseconds, frequency 40 kHz, and exposure amount 20 to 200 mJ/cm ^2. Next, the exposed curable layer was shower-developed at 23° C. for 60 seconds using a 0.3 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) as a developer. Then, the wafer was rinsed with pure water by spin shower to form pixels on the silicon wafer. This produced a silicon wafer with a pattern.
The obtained pixels were observed at a magnification of 20,000 times using a scanning electron microscope (S-4800H, manufactured by Hitachi High-Technologies Corporation). Based on the observed images, the sensitivity (exposure sensitivity), rectangularity, hydrolysis resistance, and storage stability were evaluated according to the following criteria.

-Sensitivity evaluation-
The exposure dose required for the pattern line width to reach 0.7 μm was calculated, and the sensitivity was evaluated according to the following criteria.
<Evaluation criteria>
A: The exposure amount is 30 mJ/ ^cm2 or less.
B: The exposure amount is more than 30 mJ/ ^cm2 and is 50 mJ/ ^cm2 or less.
C: The exposure amount is more than 50 mJ/ ^cm2 and is 100 mJ/ ^cm2 or less.
D: The exposure amount is more than 100 mJ/ ^cm2 and is 200 mJ/ ^cm2 or less.
E: The exposure amount exceeds 200 mJ/ ^cm2 .

- Evaluation of rectangularity -
The obtained silicon wafer with the pattern was cut in a direction perpendicular to the surface direction, and a cross section was formed of the portion (pattern) of the obtained pixel that was exposed with an exposure dose of 100 mJ/cm ^2. The formed cross section was magnified 20,000 times using a scanning electron microscope (SEM), and the widths of the upper and lower parts in the thickness direction of the pattern were measured from the enlarged image, and the rectangularity was evaluated based on the following criteria.
<Evaluation criteria>
A: The width of the lower part of the pattern that is in contact with the silicon wafer is in the range of 95% to 105% of the width of the upper part.
B: The width of the lower part of the pattern that is in contact with the silicon wafer is 90% or more and less than 95% of the width of the upper part, or is more than 105% and 110% or less.
C: The width of the lower part of the pattern that is in contact with the silicon wafer is 85% or more and less than 90% of the width of the upper part of the pattern, or is more than 110% and less than 115%.
D: The width of the lower part of the pattern that is in contact with the silicon wafer is 80% or more and less than 85% of the width of the upper part of the pattern, or is more than 115% and 120% or less.
E: The width of the lower part of the pattern in contact with the silicon wafer is less than 80% or exceeds 120% of the width of the upper part.

-Evaluation of hydrolysis resistance-
The above-mentioned "evaluation of exposure sensitivity" was carried out on the curable composition immediately after preparation and the curable composition which had been left in a 45°C environment for 3 days after preparation at the same time, and the exposure amount required for the pattern line width to reach 0.7 μm was calculated to obtain the difference in exposure amount. Then, the hydrolysis resistance was evaluated based on the following criteria.
<Evaluation criteria>
A: The difference in exposure amount is 1% or less.
B: The difference in exposure amount is more than 1% and is 5% or less.
C: The difference in exposure amount is more than 5% and is 10% or less.
D: The difference in exposure amount is more than 10% and is 50% or less.
E: The difference in exposure amount exceeds 50%.

- Evaluation of storage stability -
The viscosity (mPa·s) of the curable composition was measured using "RE-85L" manufactured by Toki Sangyo Co., Ltd. After the measurement, the curable composition was left to stand at 45°C, shielded from light, for 3 days, and the viscosity (mPa·s) was measured again. The storage stability was evaluated from the difference in viscosity (ΔVis) before and after standing according to the following evaluation criteria. It can be said that the smaller the value of the viscosity difference (ΔVis), the better the storage stability of the curable composition and the better the dispersibility of the pigment. The viscosity measurements were all performed in a room where the temperature and humidity were controlled to 22±5°C and 60±20% RH, with the temperature of the curable composition adjusted to 25°C.
<Evaluation criteria>
A: ΔVis is 0.5 mPa·s or less.
B: ΔVis exceeds 0.5 mPa·s and is 1.0 mPa·s or less.
C: ΔVis exceeds 1.0 mPa·s and is 2.0 mPa·s or less.
D: ΔVis exceeds 2.0 mPa·s and is 2.5 mPa·s or less.
E: ΔVis exceeds 2.5 mPa·s.

As is clear from the above results, in all of the Examples, the sensitivity was high, and the cross-sectional shape of the formed patterns was excellent in terms of rectangularity. In contrast, in all of the Comparative Examples, the sensitivity was low compared to the Examples, and the cross-sectional rectangularity of the patterns was also poor.

The disclosure of Japanese Patent Application No. 2023-031436, filed on March 1, 2023, is incorporated herein by reference in its entirety.
All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims

A radical polymerization initiator represented by formula (1),
A radical curable compound;
a resin having a crosslinkable group and a graft chain;
1. A curable composition comprising:

In formula (1), X represents a divalent organic group; R 11 and R 12 each independently represent an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, or a heteroaryloxy group; R 21 and R 22 each independently represent a monovalent organic group, or a divalent organic group linked to X; and n1 and n2 each independently represent 0 or 1.
The curable composition according to claim 1, wherein R 11 and R 12 in formula (1) each independently represent a group having 3 or more carbon atoms.
The curable composition according to claim 1 or 2, wherein R 11 and R 12 in the formula (1) each independently represent a branched alkyl group or an alicyclic alkyl group.
The curable composition according to claim 1 or 2, wherein R 11 and R 12 in the formula (1) are the same group and are a group represented by the following formula (4):

In formula (4), Rx1 and Rx2 each independently represent an alkyl group, Rx3 represents a hydrogen atom or an alkyl group, two or more of Rx1 to Rx3 may be bonded to each other to form a ring, and * represents a linking portion to a carbon atom in the ester structure.
The curable composition according to claim 1 or 2, wherein X in the formula (1) represents any one of the following (X-1) to (X-14):

In (X-1) to (X-14), R X1 to R X9 each independently represent a hydrogen atom, an alkyl group or an aryl group, L represents a divalent linking group, and * represents a linking portion to a (keto)oxime group.
The curable composition according to claim 1 or claim 2, further comprising a coloring material.
The curable composition according to claim 1 or claim 2, further comprising a multifunctional thiol compound.
The curable composition according to claim 1 or 2, wherein the resin having a crosslinkable group and a graft chain is an acrylic resin.
The curable composition according to claim 1 or 2, wherein the resin having a crosslinkable group and a graft chain has at least one group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group.
The curable composition according to claim 1 or 2, wherein the crosslinkable group is at least one group selected from the group consisting of an ethylenically unsaturated group and a cyclic ether group.
The curable composition according to claim 1 or 2, wherein the content of the radical curable compound having a molecular weight of less than 3000 is less than 15 mass% relative to the total solid content of the radical curable compound.
The curable composition according to claim 11, wherein the content of the radical curable compound having a molecular weight of less than 3,000 is W C1 and the content of the radical polymerization initiator represented by formula (1) is W A , the mass ratio W C1 /W A is less than 5.
The curable composition according to claim 1 or 2, which is for use in excimer laser exposure with a wavelength of 150 nm to 300 nm.
A method for producing a cured product, comprising the step of irradiating the curable composition according to claim 1 or 2 with excimer laser light having a wavelength of 150 nm to 300 nm.
A film obtained by curing the curable composition according to claim 1 or 2.
An optical element comprising the film according to claim 15.
An image sensor including the film according to claim 15.
A solid-state imaging device including the film according to claim 15.
An image display device including the film according to claim 15.
A radical polymerization initiator represented by formula (3):

In formula (3), X represents a divalent organic group, R21 and R22 each independently represent a monovalent organic group, or a divalent organic group linked to X, Rx1 and Rx2 each independently represent an alkyl group, Rx3 each independently represent a hydrogen atom or an alkyl group, two or more of Rx1 to Rx3 may be bonded to each other to form a ring, and n1 and n2 each independently represent 0 or 1.