JPH03200256A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To obtain a photopolymerizable compsn. having a high rate of photopolymn. by incorporating an addition-polymerizable compd. which is liq. or solid at ordinary temp. and pressure and a specified photopolymn. initiator. CONSTITUTION:This photopolymerizable compsn. contains an addition- polymerizable compd. which is liq. or solid at ordinary temp. and pressure and a photopolymn. initiator. This initiator is based on a sulfide compd. represented by formula I and contains at least a prescribed benzophenone compd., an alkylaminobenzophenone compd., a 2,4,5-triarylimidazolyl dimer and a triarylmethane leuco dye. In the formula I, each of R<1>-R<3> is H or a group such as alkyl which may have a substituent or aryl which may have a substituent, each of l and n is an integer of 1-5 and m is an integer of 1-4. This compsn. can be cured in a short time by irradiation with light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photopolymerizable composition having a high photopolymerization rate.

[Prior art and problems to be solved by the invention] Conventionally, organic solvent-containing coating compositions and aqueous coating compositions have been known as coating compositions applied to paper, plastic films and sheets, metals, etc. ing. Films made from these coating compositions are usually formed by heat curing, but the energy efficiency is insufficient and the curing speed is slow, so a large amount of thermal energy is required for heat curing. Furthermore, in order to increase productivity, it is necessary to lengthen the heat curing line.

On the other hand, photopolymerizable compositions that are polymerized and cured by irradiation with light such as ultraviolet rays are known as coating compositions that have good energy efficiency and productivity and have excellent properties of cured films.

This photopolymerizable composition usually contains an addition polymerizable compound having at least one ethylenically unsaturated bond and a photopolymerization initiator. The photopolymerization rate of the photopolymerizable composition is largely influenced by the type of photopolymerization initiator.

Known examples of this photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzyl. In addition, as a photopolymerization initiator that has better photopolymerization than the various photoinitiators mentioned above, a photopolymerization initiator that combines benzophenone and N,N'-bis(diethylamino)benzophenone, a photopolymerization initiator that combines benzophenone and N,N'-bis(diethylamino)benzophenone, a lofin dimer, and a lofin dimer. A photopolymerization initiator comprising a leucotriphenylmethane dye (Japanese Patent Publication No. 37377/1983) has been proposed. However, photopolymerizable compositions containing these photopolymerization initiators still do not have a sufficient photopolymerization rate.

Therefore, an object of the present invention is to provide a photopolymerizable composition with a high photopolymerization rate.

[Structure of the Invention] As a result of intensive research, the present inventors found that when a photopolymerizable composition containing a specific combination of photopolymerization initiators is irradiated with light,
They discovered that it cures within a short time and completed the present invention. That is, the present invention provides a photopolymerizable composition containing an addition polymerizable compound that is liquid or solid at room temperature and normal pressure, and a photopolymerization initiator, wherein the photopolymerization initiator has the following general formula [1 ] (wherein RI R2 and R3 are the same or different and are a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent) , an alkoxy group, and an aralkyl group, and J
and n represents an integer of 1 to 5, and m represents an integer of 1 to 4. )
, (B) a benzophenone compound optionally having a substituent selected from the group consisting of a halogen atom, an alkyl group, an aryl group optionally having a substituent, an alkoxycarbonyl group, and an alkoxy group, (C ) an alkylaminobenzophenone compound which may have a substituent selected from the group consisting of a halogen atom, an alkyl group, an aryl group which may have a substituent, an alkoxycarbonyl group, and an alkoxy group; (D) A photopolymerizable composition containing at least a 2,4.5-doryarylimidazolyl dimer which may have a substituent and (E) a triarylmethane leuco dye is provided.

The addition polymerizable compound is not particularly limited as long as it is a liquid or solid at room temperature and normal pressure and has at least one α,β-ethylenically unsaturated group in the molecule, but from the viewpoint of photopolymerizability, Two or more acryloyl groups and/or
Or a compound having a methacryloyl group is preferable. Examples of acrylates having two acryloyl groups in the molecule include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, and dipropylene glycol. Diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4
-Butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 2,2-bis(4-acryloyljethoxyphenyl)propane, 2,2-bis(4-acryloylpentaethoxyphenyl)propane Diacrylates of ethylene oxide adducts of bisphenol A, such as 2.
Diacrylates of propylene oxide adducts of bisphenol A such as 2-bis(4-acryloyldipropoxyphenyl)propane and 2.2-bis(4-acryloylpentapropoxyphenyl)propane, ethylene oxide adducts of hydrogenated bisphenol A Examples include diacrylate, diacrylate of propylene oxide adduct of hydrogenated bisphenol A, N,N'-methylenebisacrylamide, and N+N'-benzylidenebisacrylamide.

Examples of acrylates having three or more acryloyl groups in the molecule include glycerin triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, etc. is exemplified.

Examples of methacrylates having two or more methacryloyl groups in the molecule include methacrylates corresponding to the above-mentioned acrylates.

Further, the addition polymerizable compound having two or more acryloyl groups and/or methacryloyl groups in the molecule may be an oligomer (for example, epoxy acrylate, oligoester acrylate, urethane acrylate, etc.). An example is a methacrylate corresponding to

These addition polymerizable compounds can be used alone or in combination of two or more.

Note that the addition polymerizable compound may be used in combination with a compound having one α,β-ethylenically unsaturated group in the molecule. Examples of such compounds include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate,
Examples include acrylamide, N-methylolacrylamide, acrylic acid and its derivatives, corresponding methacrylic acid and its derivatives, styrene, vinyl ester, and the like.

The photopolymerization initiator includes a sulfide compound represented by the general formula [11] as component (A).

In the sulfide compound represented by the general formula [1F,
Examples of the alkyl groups for the substituents RI R2 and R3 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tart-butyl, pentyl, hexyl, and octyl groups.

Examples of the aryl group include phenyl, naphthyl, and anthryl groups.

Substituents for alkyl groups include halogen atoms such as fluorine, chlorine, and bromine, hydroxy groups, alkoxy groups such as methoxy, ethoxy, and propoxy groups, carboxyl groups, and alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, and propoxycarbonyl groups; Examples include amino groups, alkylamino groups such as dimethylamino and diethylamino groups, nitro groups, and cyano groups. Examples of substituents for the aryl group include the alkyl groups described above and substituents for the alkyl groups described above.

Alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tar
Examples include t-butoxy, pentyloxy, hexyloxy, heptyloxy, and octyloxy groups.

Examples of the aralkyl group include benzyl, phenethyl, 3-phenylpropyl, and benzhydryl groups.

Substituents RI R2 and R3 may be substituted at appropriate positions on the benzene ring, and the same or different substituents may be substituted on the same benzene ring.

Of the above substituents, R1 and R2 are each a hydrogen atom,
R3 is preferably a lower alkyl group, particularly an alkyl group having 1 to 6 carbon atoms, especially an alkyl group having 1 to 4 carbon atoms.

Among the sulfide compounds represented by the general formula [11], particularly preferred compounds include, for example, 4-benzoyl-4
'-Methyldiphenyl sulfide, 4-benzoyl-4
' -ethyldiphenyl sulfide, 4-benzoyl-
Examples include 4'-propyldiphenyl sulfide, 4-benzoyl-4'-isopropyldiphenyl sulfide, and 4-benzoyl-4-butyldiphenyl sulfide.

One or more types of these sulfide compounds can be used.

Further, the photopolymerization initiator contains at least one benzophenone compound which may have a substituent as component (B). Examples of the above substituent include the halogen atom, alkyl group, aryl group which may have a substituent, alkoxy group, and alkoxycarbonyl group. A preferred benzophenone compound is benzophenone.

At least one of these benzophenone compounds is used.

The amount of the benzophenone compound is usually 50 to 500 per 11 parts of 100ffI of the compound represented by the general formula [1].
It is used in an amount of 100 to 400 parts by weight, more preferably 200 to 350 parts by weight. When the amount of the benzophenone compound is out of the above range, photosensitivity decreases.

Examples of the substituent of the alkylaminobenzophenone compound contained as component (C) in the photom-initiator include the above-mentioned halogen atoms, alkyl groups, aryl groups that may have substituents, alkoxy groups, and alkoxycarbonyl. Examples include groups. Examples of alkylaminobenzophenone compounds include 4-methyl-4'-diethylaminobenzophenone, 4-methoxy-4'-diethylaminobenzophenone, 4,4'-bis(methylamino)benzophenone, and 4-methylamino-4'- Also included are dithylaminobenzophenone, 4-diethylaminobenzophenone, and the like. A preferred alkylaminobenzophenone compound is 4,4'-bis(alkylamino)benzophenone. Examples of 4.4'-bis(alkylamino)benzophenone include 4.4'-bis(dimethylamino)benzophenone, 4-dimethylamino-4
' -diethylaminobenzophenone, 4.4' -
Bis(diethylamino)benzophenone, 4.4'-bis(dipropylamino)benzophenone, 4゜4'-bis(diisopropylamino)benzophenone, 4.4'-
Bis(dibutylamino)benzophenone, 4.4'-bis(diisobutylamino)benzophenone, 4.4'-
Examples include bis(di-Lcrt-butylamino)benzophenone. Among these compounds, 4,4'-bis(
Particularly preferred are dimethylamino)benzophenone and 4,4'-bis(diethylamino)benzophenone. At least one alkylaminobenzophenone compound is used.

The ratio of the alkylaminobenzophenone compound to 1 part of the compound represented by the general formula [11] is:
Usually, it is 5 to 250 parts by weight, preferably 10 to 200 parts by weight, and more preferably 20 to 175 parts by weight. When the amount of the alkylaminobenzophenone compound is out of the above range, photosensitivity decreases.

Furthermore, the photopolymerization initiator contains, as component (D), a 2,4.5-1-rearylimidazolyl dimer which may have a substituent. This 2,4.5-triarylimidazolyl dimer is represented by the following general formula [11].

(In the formula, Ar' Ar2 and Arff represent an aryl group which may have a substituent.) Examples of the above-mentioned substituents include the halogen atom and alkoxy group listed above, and alkylthio groups such as methylthio and ethylthio groups. be done.

Examples of the 2,4.5-)lyarylimidazolyl dimer represented by the general formula [■] include 2°2', 4.4
' , 5.5'-hexaphenylbisimidazole,
2.2'-di(0-chlorophenyl)-4,4', 5
．． 5'-tetraphenylbisimidazole, 2.2'
-di(p-chlorophenyl)-4,4', 5.5'
-tetraphenylbisimidazole, 2,2'-di(0
-chlorophenyl)-4,4',5,5'-tetra(
m-methoxyphenyl)bisimidazole, 2.2'
-di(p-chlorophenyl)-4,4', 5.5'
Tetu(m-methoxyphenyl)bisimidazole, 2
．． 2'-di(0-fluorophenyl)-4゜4', 5
．． 5'-tetraphenylbisimidazole, 2.2'
-di(p-fluorophenyl)-4゜4', 5.5'
-tetraphenylbisimidazole, 2,2'-di(
0-methoxyphenyl)-44' 5 5' -
Tetraphenylbisimidazole, 2,2'-di(p-
methoxyphenyl)-4゜4',5.5'-tetraphenylbisimidazole, 22'-di(2,4-dimethoxyphenyl)-4,4',5.5'-tetraphenylbisimidazole, 2.2 '4,4'-tetra(p-methoxyphenyl)-5,5'-diphenylbisimidazole, 2+2'-di(p-methylthiophenyl)-4,4', 5,5'-tetraphenylbisimidazole, etc. Illustrated. At least one type of 2,4.5-triarylimidazolyl dimer represented by the above general formula [11] is used.

2.4.5-Triarylimidazolyl dimer is usually used in a proportion of 50 to 400 parts by weight, preferably 100 to 300 parts by weight, based on 100 parts by weight of the compound represented by the general formula [11]. Ru. 2°4.5-) If the amount of the realyl imidazolyl dimer is out of the above range, photosensitivity will not be sufficient.

Furthermore, the photopolymerization initiator contains a triarylmethane leuco dye as component (E). The triarylmethaneleuco dye contains a substituted amino group, in particular at least one
Those having 2 dialkylamino groups are preferred and function as free radical generators. Examples of triarylmethane leuco dyes include tris(4-N N-
diethylamino-0-tolyl)methane trihydrochloride, bis(4-N,N-diethylamino-0-tolyl)thienylmethane, bis(4-N,N-diethylamino-0-tolyl)benzylthiophenylmethane, leucomalachite green ( C, 1, 1lasic green 4),
o Ico Crystal Violet (C, 1, Ba5ic
violet3), brilliant green (C,1,I
) aslc green l), Bic, tria green 3 B (C, 1, Ba5ic green 4), acid green GG (C, 1, Ac1d green
n 3), methyl violet (C,1,[3asl
c violet l) o-zuaniline (C,1
, l3aslc violet 14), etc. These triarylmethane leuco dyes are hydrochloride,
It can be used as a mineral acid salt such as sulfate or an organic acid salt such as p-toluenesulfonate. At least one triarylmethane leuco dye can be used.

The triarylmethane leuco dye is generally used in an amount of 10 to 70 parts by weight, preferably 25 to 55 parts by weight, based on 100 parts by weight of the compound represented by the general formula [1].

When the amount of triarylmethane leuco dye is out of the above range, photosensitivity decreases.

(A) Sulfide compound represented by general formula [1], (
B) Benzophenone compound, (C) Alkylaminobenzophenone compound, (D) 2.4. In order to further enhance the photopolymerizability of a photopolymerizable composition containing a photopolymerization initiator consisting of a combination of a 5-triarylimidazolyl dimer and (r,) triarylmethaneleuco dye,
Preferably, the photo-1 initiator contains (r')p(dialkylamino)benzoic acid alkyl ester.

The p-(dialkylamino)benzoic acid alkyl ester is represented by the following general formula [I[1].

(In the formula, R4R5 and R6 are the same or different and represent a lower alkyl group) Examples of the lower alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tart
- Straight chain or branched chain alkyl groups such as butyl, pentyl, hexyl and octyl groups are exemplified. Among these alkyl groups, alkyl groups having 1 to 6 carbon atoms, particularly 1 to 3 carbon atoms, are preferred.

Preferred p-<dialkylamino)benzoic acid alkyl esters include, for example, methyl p-(dimethylamino)benzoate, ethyl p-(dimethylamino)benzoate,
Propyl p-(dimethylamino)benzoate, isopropyl p-(dimethylamino)benzoate, methyl p-(N-methyl-N-ethylamino)benzoate, p-(N-methyl-N-ethylamino)benzoate ethyl acid, methyl p-(diethylamino)benzoate, ethyl p-(diethylamino)benzoate, propyl p-(diethylamino)benzoate, isopropyl p-(diethylamino)benzoate, p
Examples include methyl -(dipropylamino)benzoate, ethyl p-(dipropylamino)benzoate, propyl p-(dipropylamino)benzoate, and isopropyl p-(dipropylamino)benzoate. One or more types of p-(dialkylamino)benzoic acid alkyl esters represented by the general formula [■] can be used.

The p-(dialkylamino)benzoic acid alkyl ester is a sulfide compound 10 represented by the general formula [11].
It is usually used in a proportion of 25 to 200 parts by weight, preferably 50 to 100 parts by weight. When the amount of p-(dialkylamino)benzoic acid alkyl ester is out of the above range, the polymerization rate of the photopolymerizable composition tends to decrease.

The photopolymerization initiator consisting of components (A) to (IE) or components (A) to (F) exhibits a high photopolymerization rate because the excitation and energy transition of the photopolymerization initiator by light irradiation proceed smoothly. However, it is presumed that the addition polymerizable substance is radically polymerized efficiently.

Note that the photopolymerization initiator may contain substituted or unsubstituted polynuclear borons, benzoins, benzoin ethers, substituted or unsubstituted thioxanthone, etc., as necessary. Examples of substituted or unsubstituted polynuclear quinones include 2-methylanthraquinone, 2-ethylanthraquinone, 2-propylanthraquinone, 2-Lcr
L-butylanthraquinone, octamethylanthraquinone, 1,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, benz[al anthraquinone, benz[b]anthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone , 2-chloroanthraquinone, 3-chloro-
2-methylanthraquinone, 1,4-natsutaquinone, 9
．． Examples include 10-phenanthraquinone, 2-methyl-1,4-natutaquinone, 2,3-dichloronaphthaquinone, and 7,8°9.10-tetrahydronaphthacenequinone. As benzoins and benzoin ethers,
Examples include benzoin, methylbenzoin, ethylbenzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether.

Examples of substituted or unsubstituted thioxanthone include:
Examples include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2.4-dibutylthioxanthone. Examples of other photopolymerization initiators include benzyl, α, α-jethoxyacetophenone, and oxime esters such as benzophenone oxime acetate.

Examples of the photopolymerization initiator include 2-mercaptobenzoxazole, ethanolamine, jetanolamine, triethanolamine, diethylaminoethanol, N-methyljetanolamine, N-ethyljetanolamine, and Nn-butyljetanol. Amine, allylthiourea, N, N-diethylglycine, aniline, N
- It is useful to use it in combination with aliphatic or aromatic amines such as methylaniline, N,N-diethylaniline, and N-ethylmorpholine.

The photopolymerization initiator is generally used in an amount of 0.1 to 30 parts by weight, preferably 1 to 25 parts by weight, per 100 parts by weight of the addition polymerizable compound. If the amount of the photopolymerization initiator is less than 0, t parts by weight, the photopolymerizability will decrease, and if it exceeds 30 parts by weight, the stability of the photopolymerizable composition will decrease.

The photopolymerizable composition of the present invention may contain a stabilizer, a colorant, a plasticizer, a filler, etc., which suppress the thermal polymerization reaction and improve storage stability, as necessary.

Examples of the stabilizer include p-methoxyphenol, hydroquinone, hydroquinone monomethyl ether, t
An example is orL-butylcatechol, which is used in an appropriate amount within a range that does not inhibit photopolymerization.

Examples of tube colorants include various dyes such as crystal violet, malachite green, Victoria blue, methylene blue, etc., and pigments. Examples of plasticizers include phthalic acid esters such as diethyl phthalate, dibutyl phthalate, diethyl phthalate, and dioctyl phthalate; fatty acid esters such as dioctyl adipate and dibutyl diglycol adipate;
Examples include phosphoric acid esters such as trimethylphosphine; and sulfonic acid amides such as toluenesulfonic acid amide. Examples of fillers include talc, kaolin, calcium carbonate, barium sulfate, and the like.

Furthermore, the photopolymerizable composition of the present invention can be applied to organic polymers such as acrylic polymers, styrenic polymers, polyvinyl acetate, ethylene-vinyl acetate, polyvinyl chloride,
Vinyl chloride-vinyl acetate co-m combination, chlorinated polyethylene, chlorinated polypropylene, vinylidene chloride polymer
Cellulose polymers such as polyester, polyamide, polyurethane, polyvinyl acecool, alkyd resin, phenol resin, epoxy resin, cellulose acetate, nitrated cotton, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, chlorinated rubber, cyclized It may contain synthetic rubber such as rubber or natural rubber. Further, the organic polymer may be an alkali-soluble polymer having a carboxyl group.

Further, the photopolymerizable composition may contain oils and fats, wax, and the like.

The photopolymerizable composition of the present invention may contain an organic solvent, if necessary. Examples of the organic solvent include:
Alcohols such as methanol, ethanol and propatool, alicyclic hydrocarbons such as hexane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, esters such as ethyl acetate, ketones such as acetone and methyl ethyl ketone, diethyl Examples include ethers, ethers such as tetrahydrofuran, halogenated hydrocarbons such as methylene chloride, and mixed solvents thereof.

The photosensitive layer made of the photopolymerizable composition of the present invention can usually be formed by printing or applying the liquid photopolymerizable composition onto a material to be coated, such as paper, plastic, metal, or the like. The above application means include spray coating, dip coating, roller coating,
Conventional means such as doctor blade coating can be employed.

The photosensitive layer is exposed to a light source that generates chemically active light, such as a low-pressure mercury lamp, an extra-high pressure mercury lamp, or a xenon lamp, and is cured within a short time. As the active light, a light having a wavelength matching the absorption wavelength of the photopolymerization initiator is used, preferably an active light having a wavelength in the ultraviolet to visible light range of 250 to 500 nIl. Note that electron beams, X-rays, etc. can also be used.

[Effects of the Invention] According to the photopolymerizable composition of the present invention, since it contains an addition polymerizable compound and a photopolymerization initiator consisting of a specific combination,
It hardens within a short time by light irradiation.

[Example] Hereinafter, the present invention will be explained in more detail based on Examples.

Examples 1 to 4 and Comparative Examples 1 to 8 A photopolymerizable composition was obtained by mixing a photopolymerization initiator in the proportion shown in the table to a solution of an addition polymerizable compound consisting of the following components.

5 g of trimethylolpropane triacrylate, 0 g of tetraethylene glycol diacrylate, and 30 g of methyl ethyl ketone were applied to a copper plate using an applicator and dried to form a photosensitive layer. Next, the photosensitive layer was irradiated in air with a 2 Kw ultra-high pressure mercury lamp from a distance of 50 cm until the photosensitive layer lost its tackiness, and this irradiation time was defined as the curing time. The results are shown in the table.

(Hereinafter, blank space) As is clear from the table, the photopolymerizable compositions of each Example cure in a shorter time than those of each Comparative Example.

Example 5 The curing time was examined in the same manner as in Example 1 except that 4-benzoyl-4'-ethyldiphenyl sulfide was used in place of component (A), and the curing time was 8 seconds.

Example 6 The curing time was examined in the same manner as in Example 1 except that 4,4'-bis(dimethylamino)benzophenone was used instead of component (C), and it was cured in 8 seconds.

Example 7 The procedure was repeated in the same manner as in Example 1 except that 2,2'-di(p-methoxyphenyl)-4,4',5,5'-tetraphenylbisimidazole was used instead of component (1)). When the curing time was examined, it was cured in 8 seconds.

Example 8 The curing time was examined in the same manner as in Example 1 except that leucomalachite green was used instead of component (I), and the curing time was 8 seconds.

Example 9 The same procedure as Example 1 was repeated except that ethyl p-(diethylamino)benzoate was used in place of component (F), and the curing time was 1 week, and the product was cured in 8 seconds.

Claims (1)

[Claims] 1. A photopolymerizable composition containing an addition polymerizable compound that is liquid or solid at room temperature and normal pressure, and a photopolymerization initiator, wherein the photopolymerization initiator has the following general formula: (A) Sulfide compounds represented by [I]▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, R^1, R^2 and R^3 are the same or different, and each represents a hydrogen atom, a substituent represents a group selected from the group consisting of an alkyl group that may have a substituent, an aryl group that may have a substituent, an alkoxy group, and an aralkyl group, l and n are integers of 1 to 5, and m is an integer of 1 to 5. (B) has a substituent selected from the group consisting of a halogen atom, an alkyl group, an aryl group that may have a substituent, an alkoxycarbonyl group, and an alkoxy group. (C) A benzophenone compound that may have a substituent selected from the group consisting of a halogen atom, an alkyl group, an aryl group that may have a substituent, an alkoxycarbonyl group, and an alkoxy group. A light characterized by containing at least an alkylaminobenzophenone compound, (D) a 2,4,5-triarylimidazolyl dimer which may have a substituent, and (E) a triarylmethane leuco dye. Polymerizable composition. 2. The photopolymerizable composition according to claim 1, wherein the photopolymerization initiator contains p-(dialkylamino)benzoic acid alkyl ester. 3. The alkylaminobenzophenone compound is 4,4
The photopolymerizable composition according to claim 1 or 2, which is '-bis(dialkylamino)benzophenone.