JPH07333847A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To obtain a photopolymerizable compsn. excellent in sensitivity, development latitude, gradation, ink receptivity and printing resistance in a well- balanced state. CONSTITUTION:This photopolymerizable compsn. consists of an additionpolymerizable compd. having at least one ethylenic unsatd. bond, a photopolymn. initiator which is activated by active light and a polymer binder which is a multiple copolymer contg. at least one kind of alkyl methacrylate having a branched structure, at least one kind of alkyl acrylate having a branched structure, methyl methacrylate and methacrylic acid as copolymer components and having a wt. average mol.wt. of 10,000-500,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable composition used for a photosensitive lithographic printing plate or photoresist. More specifically, the present invention relates to a photopolymerizable composition which has extremely high sensitivity to light rays in the visible region and which is excellent in developability, ink receptivity, gradation and printing durability.

[0002]

2. Description of the Related Art Conventionally, many photopolymerizable compositions containing a copolymer of (meth) acrylic acid and a (meth) acrylic acid ester as a binder polymer are known, for example, Japanese Patent Publication No. 54-34327. Kosho 58-1257
7, JP-A-60-159743 and JP-A-60-
It is described in each publication of 208748. However, the performance of these conventional compositions cannot be said to be sufficient, and improvements have been desired especially in terms of ink receptivity and gradation.

Further, in recent years, high-sensitivity light-sensitive materials using photopolymerizable light-sensitive materials have been investigated in various fields of application. Among these, there is laser direct plate making as a system that is considered to be practically practical, and the laser oscillation wavelength, for example,
There is a strong demand for a high-sensitivity photopolymer system compatible with 488 nm of an argon ion laser.

[0004]

However, conventionally used photopolymerizable compositions have well-balanced properties such as developability, ink receptivity, sensitivity, gradation and printing durability. There was nothing.

[0005]

Means for Solving the Problems As a result of intensive studies to solve such problems, the present inventors have found that an addition-polymerizable compound having at least one ethylenically unsaturated bond and a light activated by an actinic ray. By providing a photopolymerizable composition containing a polymerization initiator and a specific copolymer component, and a polymer binder having a specific weight average molecular weight, sensitivity, development acceptability, and ink receptivity are obtained. The present invention has been accomplished by finding that it is possible to provide well-balanced performances such as gradation and printing durability.

That is, the object of the present invention is to provide a photopolymerizable composition which has a very high sensitivity to light rays in the visible region and which is excellent in developability, ink receptivity, gradation and printing durability. Especially. Therefore, the object of the present invention is to provide (A) an addition-polymerizable compound having at least one ethylenically unsaturated bond, (B) a photopolymerization initiator activated by actinic rays, and (C) a high amount. In a photopolymerizable composition comprising a molecular binder, the polymer binder is (a) a methacrylic acid alkyl ester having a branched structure, (b) an acrylic acid alkyl ester having a branched structure, (c) methyl methacrylate and (d) It has at least one copolymer component selected from each group of methacrylic acid and has a weight average molecular weight of 10,000 to 50.
It is easily achieved by a photopolymerizable composition characterized in that it is a multi-component copolymer of 10,000.

The present invention will be described in detail below. In the photopolymerizable composition of the present invention, an addition-polymerizable compound having at least one ethylenically unsaturated double bond contained as the first essential component represented by (A) (hereinafter referred to as “ethylenic compound”) Abbreviated) means that when the photopolymerizable composition is irradiated with an actinic ray, an ethylenically unsaturated double bond that undergoes addition polymerization by the action of the photopolymerization initiation system, which is the second essential component, and is cured. A compound having
For example, it is a monomer having the above double bond, or a polymer having an ethylenically unsaturated double bond in the side chain or main chain. Incidentally, the meaning of the monomer in the present invention is a concept facing a so-called polymer substance, and therefore includes not only a narrowly defined monomer but also a dimer, a trimer and an oligomer. is there.

Examples of the monomer having an ethylenically unsaturated bond include unsaturated carboxylic acids, esters of aliphatic polyhydroxy compounds with unsaturated carboxylic acids; esters of aromatic polyhydroxy compounds with unsaturated carboxylic acids; Examples thereof include an ester obtained by an esterification reaction of an unsaturated carboxylic acid with a polyvalent carboxylic acid and the aforementioned polyvalent hydroxy compound such as an aliphatic polyhydroxy compound and an aromatic polyhydroxy compound.

Examples of the ester of the aliphatic polyhydroxy compound and the unsaturated carboxylic acid include ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol diacrylate, Acrylic esters such as pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and glycerol acrylate, and methacrylic acid esters in which acrylates of these exemplary compounds are replaced with methacrylates, Similarly, itaconic acid ester replaced with itaconate, crotonate instead And there is a maleic acid ester or the like in place of crotonic acid ester or maleate.

Examples of the ester of an aromatic polyhydroxy compound and an unsaturated carboxylic acid include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate and pyrogallol triacrylate. The ester obtained by the esterification reaction of the unsaturated carboxylic acid and the polyvalent hydroxy compound is not necessarily a single substance,
Representative specific examples include condensates of acrylic acid, phthalic acid and ethylene glycol, condensates of acrylic acid, maleic acid and diethylene glycol, condensates of methacrylic acid, terephthalic acid and pentaerythritol, acrylic acid, adipic acid, Examples include condensates of butanediol and glycerin.

Other examples of the ethylenic compound used in the present invention include urethane acrylates such as addition reaction products of tolylene diisocyanate and hydroxyethyl acrylate; addition reaction products of diepoxy compounds and hydroxyethyl acrylate. Epoxy acrylates; acrylamides such as ethylene bis acrylamide; allyl esters such as diallyl phthalate; vinyl group-containing compounds such as divinyl phthalate are useful.

The above-mentioned polymer having an ethylenically unsaturated bond in the main chain is, for example, a polyester obtained by a polycondensation reaction of an unsaturated divalent carboxylic acid and a dihydroxy compound, or an unsaturated divalent carboxylic acid and a diamine. There are polyamides and the like obtained by polycondensation reaction. The polymer having an ethylenically unsaturated bond in the side chain is a polycondensation product of a divalent carboxylic acid having an unsaturated bond in the side chain, for example, itaconic acid, propylidene succinic acid, ethylidene malonic acid, etc. with a dihydroxy or diamine compound, etc. There is coalescence. Further, a polymer having a functional group having a reactive activity such as a hydroxy group or a methyl halide group in its side chain, for example, polyvinyl alcohol, poly (2-hydroxyethyl methacrylate), polyepichlorohydrin, etc. and acrylic acid, methacrylic acid, crotonic acid. Polymers obtained by a polymer reaction with an unsaturated carboxylic acid such as are also preferably used.

Of the above-mentioned ethylenic compounds, acrylic acid ester or methacrylic acid ester monomers can be particularly preferably used. Next, the photopolymerization initiator (B) which is the second essential component represented as (B) in the photopolymerizable composition of the present invention will be described. As the photopolymerization initiator, any one that can initiate the polymerization of the compound having at least one ethylenically unsaturated bond can be used, and particularly, one that is photosensitive to a light ray in the visible region is preferably used. it can. Further, the photopolymerization initiator of the present invention may be an activator that produces an active radical by causing some action with the photoexcited sensitizer.
Examples of the photopolymerization initiator used in combination with the sensitizer include hexaarylbiimidazole, titanocene compounds, halogenated hydrocarbon derivatives, diaryliodonium salts, organic peroxides and the like. Among these, a system using hexaarylbiimidazole or a titanocene compound is preferable because of good sensitivity, storability, and adhesion of the coating film to the substrate.

As the hexaarylbiimidazole,
Various materials can be used, for example, 2,2 '
-Bis (o-chlorophenyl) -4,4 ', 5,5'-
Tetra (p-fluorophenyl) biimidazole, 2,
2'-bis (o-bromophenyl) -4,4 ', 5
5'-tetra (p-iodophenyl) biimidazole,
2,2'-bis (o-chlorophenyl) -4,4 ',
5,5'-tetra (p-chloronaphthyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,
4 ', 5,5'-tetra (p-chlorophenyl) biimidazole, 2,2'-bis (o-bromophenyl)-
4,4 ', 5,5'-Tetra (p-chloro-p-methoxyphenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (o , P
-Dichlorophenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (o, p-dibromophenyl) biimidazole, 2,
2'-bis (o-bromophenyl) -4,4 ', 5
5'-tetra (o, p-dichlorophenyl) biimidazole, 2,2'-bis (o, p-dichlorophenyl)-
4,4 ', 5,5'-tetra (o, p-dichlorophenyl) biimidazole and the like can be mentioned.

These biimidazoles may be used, if necessary.
It can also be used in combination with another type of biimidazole. Biimidazoles are described, for example, in Bull. Chem.
Soc. Japan, 33 , 565 (1960) and J. Am. Org. Chem, 36 [16] 2262 (197).
It can be easily synthesized by the method disclosed in 1).

As the titanocene compound, various compounds can be used, for example, JP-A-59-1523.
It can be appropriately selected and used from various titanocene compounds described in JP-A No. 96 and JP-A No. 61-151197. More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-Pentafluorophen-1-yl, di-cyclopentadienyl-Ti-
Bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4
6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-di-fluorophenyl-
1-yl, di-cyclopentadienyl-Ti-bis-
2,4-di-fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6
-Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3 -(Pyr-1-yl) -phen-1-yl etc. can be mentioned.

Next, the sensitizer of the photopolymerization initiator will be described. The sensitizer in the present invention means a compound capable of effectively generating an active radical upon irradiation with visible light when coexisting with the above-mentioned activator. Examples of typical sensitizers include, for example, U.S. Pat. No. 3,479,18.
No. 5, such as leuco crystal violet and triphenylmethane leuco dyes such as leucomalachite green, photoreducing dyes such as erythrosine and eosin Y, US Pat. No. 3,549,367. , U.S. Pat. No. 3,652,275, and other aminophenyl ketones such as Michler's ketone and aminostyryl ketone, U.S. Pat. No. 3,844,7.
Β-diketones shown in US Pat. No. 90, indanones found in US Pat. No. 4,162,162,
Ketocoumarins disclosed in JP-A-52-112681, aminostyrene derivatives and aminophenylbutadiene derivatives disclosed in JP-A-59-56403, and US Pat. No. 4,594,310. Aminophenyl heterocycles, US Pat. No. 4,966,83
Jurolidine heterocycles shown in Japanese Patent No.
Examples include the pyrromethene dyes disclosed in JP-A-241338.

Next, the polymer binder, which is the third essential component represented by (C) in the present invention, will be explained. The polymer binder used in the present invention is (a) a methacrylic acid alkyl ester having a branched structure, (a) an acrylic acid alkyl ester having a branched structure, (c)
It contains at least one copolymer component selected from each group of methyl methacrylate and (d) methacrylic acid, and has a weight average molecular weight of 10,000 to 500,0.
00 is a multi-component copolymer.

The copolymer of the present invention can be produced by a usual radical polymerization method, and generally, a suspension polymerization method or a solution polymerization method is used. In the present invention (a)
As the methacrylic acid alkyl ester having a branched structure represented by the following, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl methacrylate, etc. can be used alone or in combination thereof. Most preferred is isobutyl methacrylate.

In the present invention, as the acrylic acid alkyl ester having a branched structure represented by (a), isopropyl acrylate, isobutyl acrylate,
Although tert-butyl acrylate, isoamyl acrylate and the like can be used alone or in combination of two or more, isobutyl acrylate is most preferable.

The range of the content of these monomers in the copolymer is expressed by the charged amount (hereinafter the same) (a) is 20 to 70 mol%, (a) is 1 to 30 mol%, It is general that (c) is 10 to 60 mol% and (d) is 3 to 30 mol%. As a more preferable content range,
(A) is 30 to 50 mol%, (A) is 1 to 20 mol%,
(C) is 20 to 50 mol%, and (D) is 5 to 20 mol%.

(A) is a component that contributes to the improvement of ink receptivity and gradation, and if it is less than 20 mol%, the ink receptivity and gradation may be poor, and if it is more than 70 mol%. The developability may deteriorate. (A) is a component that contributes to the improvement of the ink receptivity, and if it is less than 1 mol%, the ink receptivity may be poor, and if it is more than 30%, the developability may be poor. (C) is a component that contributes to the film strength. If it is less than 10 mol%, the film strength may be poor, and if it is more than 60 mol%, the gradation and the ink receptivity may be deteriorated. (D) is a component that contributes to the improvement of developability. If it is less than 3 mol%, the developability may be poor, and if it is more than 30 mol%, the solubility in the developing solution becomes excessive and the image disappears during development. It may be easier to do.

In the present invention, it is also possible to copolymerize another copolymerizable monomer to the extent that the performance of the photopolymerizable composition is not impaired in order to modify the characteristics of the photopolymerizable composition.
Examples of the copolymerizable monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and n-hexyl acrylate; ethyl methacrylate, n-methacrylate.
Propyl, n-butyl methacrylate, n-methacrylic acid
Methacrylic acid esters such as hexyl; vinyl compounds such as vinyl chloride, acrylonitrile, styrene, vinyl acetate and the like can be mentioned, and particularly preferred are the copolymerization components represented by the following general formulas (I) and (II). .

[0024]

[Chemical 3]

(In the formula, R ¹ is a hydrogen atom or a methyl group, and n is an integer of 3 to 10.)

[0026]

[Chemical 4]

(In the formula, R ² is a hydrogen atom or a methyl group, and Ar represents a phenyl group which may have a substituent) The copolymer component represented by the general formula (I) is an ink It has the effect of improving developability without sacrificing physicality, and further,
It is also effective in improving mechanical properties and adhesion to the substrate.
Among them, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate are particularly preferable. The content of this copolymer component in the copolymer is generally within the range of 30 mol%. More preferably, it is within 20 mol%. Three
If it is more than 0 mol%, the solubility in the developer becomes excessive,
The image may easily disappear during development.

The copolymer component represented by the general formula (II) is
It is effective in improving ink receptivity and gradation. Among them, benzyl acrylate and benzyl methacrylate are particularly preferable. The content of this copolymerization component in the copolymer is generally within the range of 20 mol%. More preferably, it is within 15 mol%. If it is more than 20 mol%, the developability may deteriorate.

The weight average molecular weight of the copolymer (C) of the present invention is 10,000 to 500,000, preferably 2
10,000 to 400,000, particularly preferably 30,
It is 00 to 200,000. Weight average molecular weight is 10,
If it is less than 000, the solubility in the developing solution becomes excessive, so that the image may easily disappear during development.
On the other hand, when it is more than 500,000, the developability is deteriorated and the background stain is likely to occur.

The main constituents of the photopolymerizable composition of the present invention have been described above in detail. The preferable ratio of use is 100 parts by weight of the ethylenic compound, and the sensitization of the photopolymerization initiator. The agent is preferably 0.01 to 20 parts by weight, particularly preferably 0.05 to 10 parts by weight, the activator is preferably 0.1 to 80 parts by weight, particularly preferably 0.5 to 50 parts by weight, a polymer bond. The amount of the agent is preferably 10 to 400 parts by weight, particularly preferably 20 to 200 parts by weight.

The photopolymerizable composition of the present invention may further contain other substances in addition to the above-mentioned constituents depending on the purpose of use. For example, thermal polymerization inhibitors such as hydroquinone, p-methoxyphenol, and 2,6-di-t-butyl-p-cresol; coloring agents composed of organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate, tricresyl. Plasticizers such as phosphates, sensitivity characteristic improving agents such as tertiary amines and thiols, and additives such as dye precursors can also be added.

The above-mentioned various additives are preferably added in an amount of 2 parts by weight or less of the thermal polymerization inhibitor, 20 parts by weight or less of the colorant, 40 parts by weight or less of the plasticizer, and the dye precursor, based on 100 parts by weight of the ethylenic compound. It is in the range of 30 parts by weight or less. The photopolymerizable composition described above is applied as a photosensitive layer by coating it on a support made of plastic, paper, metal or the like without being diluted with a solvent or an appropriate solvent and drying it. When used as a photosensitive lithographic printing plate, an aluminum support having its surface grained and then anodized can be preferably used. As a coating method, a known method such as dip coating, coating rod, spinner coating, spray coating or roll coating can be used.

Further, an oxygen blocking layer may be provided on the above-mentioned photosensitive layer in order to prevent the polymerization inhibiting action by oxygen. Specific examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide,
Water-soluble polymers such as cellulose can be mentioned. Among these, polyvinyl alcohol having a particularly high oxygen gas barrier property is particularly preferable.

The exposure light source applicable to the composition of the present invention is not particularly limited, and examples thereof include carbon arc, high pressure mercury lamp, xenon lamp, metal halide lamp, fluorescent lamp, tungsten lamp, halogen lamp, helium cadmium laser, argon ion. Laser, Y
An AG laser, a helium neon laser and the like can be particularly preferably used.

The photopolymerizable composition of the present invention can form an image on a support by imagewise exposure with such a light source and then development with an aqueous solution containing a surfactant and an alkali. . The aqueous solution may further contain an organic solvent, a buffer, a dye or a pigment. Suitable alkaline agents include sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate, sodium bicarbonate and the like. Examples thereof include inorganic alkaline agents and organic amine compounds such as trimethylamine, diethylamine, monoisopropylamine, n-butylamine, monoethanolamine, diethanolamine, and triethanolamine, and these can be used alone or in combination. As the surfactant, for example, polyoxyethylene alkyl ethers,
Nonionic surfactants such as polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters; alkylbenzene sulfonates,
Anionic surfactants such as alkylnaphthalene sulfonates, alkyl sulfates, alkyl sulfonates, and sulfosuccinic acid ester salts; amphoteric surfactants such as alkyl betaines and amino acids can be used. Also,
As the organic solvent, for example, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol, diacetone alcohol and the like can be contained if necessary.

[0036]

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Synthesis Example 1 Under a nitrogen stream, 240 g of methanol, 75.7 g of isobutyl methacrylate and 17.1 of isobutyl acrylate were added.
g, methyl methacrylate 46.7 g, methacrylic acid 1
7.2 g and azobisisobutyronitrile 1.2 g were dissolved and reacted with stirring at 74 ° C. for 7 hours. Next, the reaction solution was poured into water to precipitate the copolymer. This was collected by filtration and dried to obtain a copolymer. The molecular weight was measured by gel permeation chromatography, and the weight average molecular weight was 100,000.

Synthetic Examples 2 to 18 As in Synthetic Example 1, the composition ratios of charged monomers were changed.
The copolymer shown in 1 was synthesized. The weight average molecular weights of these copolymers were almost the same as those obtained in Synthesis Example 1.

(Examples 1 to 11 and Comparative Examples 1 to 7)
The photopolymerizable composition coating solution is grained and then anodized.
Dry film thickness using a whirler on an aluminum support 2
g / m²Was applied and dried. Further on
Then, dry the polyvinyl alcohol aqueous solution using a whirler.
Dry film thickness 3g / m ²Coating, dry and
A plate printing plate was prepared. On the surface of the obtained photosensitive lithographic printing plate
A step tab where the light intensity is attenuated by 1 / √2 each time it is increased by one step
Let (let's make Kodak) come in close contact, and then 50cm
500W xenon lamp (trade name; UXL-500D
-O: USHIO INC., Glass filter (product)
Name; Y-47 and KL-49: manufactured by Toshiba Glass Co., Ltd.
Irradiation of 480-490nm light obtained through
After that, potassium hydroxide 20 wt%, potassium silicate 7
5 wt%, sodium alkylnaphthalene sulfonate
(Product name: Perex NBL: manufactured by Kao Corporation) 5 wt%
With a developer diluted with water at an appropriate magnification
After development, the following items were evaluated. The result
It shows in Table-2.

1. Measurement of contact angle of water Development is carried out with a developer obtained by diluting the stock solution of the developer with water by 5 times, and the contact angle of water in the solid part is measured. The larger this value, the higher the oil sensitivity of the image area, that is, the better the ink receptivity. 2. Gradation The undiluted developer is developed with a developer diluted 5 times with water, and the number of clear steps and solid steps are measured. The smaller the difference, the shorter the halftone and the better the gradation. 3. Development Tolerance The photosensitive lithographic printing plate is developed by changing the developing solution dilution ratio by diluting the developing solution stock solution with water, and the ink is filled with the developing ink SPO-1 (manufactured by Konica Corporation). At this time, the dilution ratio of the developing solution is measured so that the solid area is completely covered with the ink and the non-image area is not contaminated with the ink.

(Examples 13 to 15 and Comparative Examples 8 to 9)
The photosensitive lithographic printing plate prepared in the same manner as in the above-mentioned Examples and Comparative Examples was scan-exposed with a 75 mW air-cooled argon ion laser at an exposure dose of 160 μJ / cm ² , and potassium hydroxide 20 wt%, potassium silicate 75 wt%, A developing solution containing 5 wt% of sodium alkylnaphthalene sulfonate (trade name; Perex NBL: manufactured by Kao Corporation) was developed with a developing solution diluted 5 times with water, and then Washgum SQW-3 (manufactured by Konica Corporation). ) Chewing gum. The printing plate is printed on the "Heidelberg GTO" printing machine,
The number of prints until the ink density of the printed matter became constant (gum removability), printing durability, and stains on non-image areas were evaluated. The results are shown in Table-3.

[0042]

[Table 1]

[0043]

Photopolymerizable composition coating liquid Copolymer having composition ratio shown in Table-1 40 parts Trimethylolpropane triacrylate 60 parts S-1 shown below 1.5 parts I-1 shown below 1 part 13 parts 2 -Mercaptobenzothiazole 10 parts Victoria Pure Blue BOH (Hodogaya Industry Co., Ltd.) 0.5 part Methyl ethyl ketone 90 parts

[0044]

[Chemical 5]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

As is clear from the results of Tables 1, 2, and 3, the photopolymerizable composition of the present invention has a good balance of sensitivity, development acceptability, gradation and ink receptivity. . Especially, it is excellent in ink receptivity during laser exposure,
As a result, even if 100,000 or more sheets are printed, defective inking does not occur and printing durability is improved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ide 1000, Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Sanryo Kasei Co., Ltd.

Claims (8)

[Claims] 1. A compound comprising (A) an addition-polymerizable compound having at least one ethylenically unsaturated bond, (B) a photopolymerization initiator activated by actinic rays, and (C) a polymer binder. In the photopolymerizable composition, the polymer binder is (a) a methacrylic acid alkyl ester having a branched structure, (b) an acrylic acid alkyl ester having a branched structure, (c) methyl methacrylate and (d) each group of methacrylic acid. Containing at least one copolymer component and having a weight average molecular weight of 10,000 to 50
A photopolymerizable composition, wherein the photopolymerizable composition is a multi-component copolymer having a content of 10,000. 2. The photopolymerizable composition according to claim 1, wherein the polymer binder (C) is a copolymer further containing a copolymer component represented by the following general formula (I). object. [Chemical 1] (In the formula, R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 3 to 10.) 3. The photopolymerizable composition according to claim 1, wherein the polymer binder (C) is a copolymer further containing a copolymer component represented by the following general formula (II). object. [Chemical 2] (In the formula, R ² represents a hydrogen atom or a methyl group, and Ar represents a phenyl group which may have a substituent) 4. The polymer binder (C) is a copolymer containing at least isobutyl methacrylate, isobutyl acrylate, methyl methacrylate and methacrylic acid as copolymer components. A photopolymerizable composition. 5. The polymer binder (C) is a copolymer containing at least isobutyl methacrylate, isobutyl acrylate, methyl methacrylate, methacrylic acid and 4-hydroxybutyl (meth) acrylate as a copolymer component. The photopolymerizable composition according to claim 1, wherein 6. The polymer binder (C) comprises at least isobutyl methacrylate, isobutyl acrylate, methyl methacrylate, methacrylic acid, 4-hydroxybutyl (meth) acrylate and benzyl (meth) acrylate as a copolymer component. The photopolymerizable composition according to claim 1, which is a copolymer of 7. The photopolymerizable composition according to claim 1, wherein the photopolymerization initiator (B) contains hexaarylbiimidazole and a sensitizer having absorption in the visible region. 8. The photopolymerizable composition according to claim 1, wherein the photopolymerization initiator (B) contains a titanocene compound and a sensitizer having absorption in the visible region.