JPS6231844A - Lithographic plate material - Google Patents

Abstract

PURPOSE:To obtain a lithographic plate material superior in photosensitivity to the visible rays and physical properties for printing by forming a photosensitive resin layer composed of an additionally polymerizable compound having an ethylenically unsaturated double bond and a specified photopolymerization initiation system on the hydrophilic surface of a support. CONSTITUTION:The photosensitive resin layer containing the additionally polymerizable compound having an ethylenically unsaturated double bond, such as an unsaturated carboxylic acid, and as the photopolymerization initiation system, xanthene or its derivative represented by the formula shown on the right and a photosensitivity promotor is formed on the hydrophilic surface of the support, such as Al, Zn, or Ni. In that formula, A is halogen; Y is a C or 0 atom, and when it is a C atom, the bond expressed with a dotted line is a double bond; Z is an 0 atom combined with an adjacent C atom through a double bond, lower alkoxy, or lower alkanoyloxy; R<1> is lower alkyl, lower hydroxyalkyl, lower-alkoxylated lower alkyl, di-(lower alkylamino)-(lower alkyl), or aryl; and R<2> is lower alkoxy or lower dialkylamino.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a lithographic plate material, particularly a lithographic plate material sensitive to visible light, and the efficient production of a lithographic printing plate using the same.

[Prior Art] A lithographic printing plate is a plate in which an image area and a non-image area are formed on the same plane on a thin dam plate generally having a thickness of 0.1 to 0.5 mm. The image area requires lipophilicity and water repellency, and the non-image area requires hydrophilicity, water retention, and ink repulsion. Various materials are known for forming the image area and non-image area, but the current mainstream is metal plates such as aluminum or zinc for the non-image area, and diazonium salts, quinone diazides, etc. for the image area. It consists of an organic photosensitive layer and is commercially available as a PS plate (a plate material on which a photosensitive layer is coated in advance).

"Problems to be Solved by the Invention" With the development of such PS plates, significant labor savings in printing work are being achieved, but there is a desire for the emergence of image forming technology that does not require negatives to further save labor. In order to develop such technology, an image forming method in which laser beams are used to draw directly onto the plate material has been considered, and the laser light source used requires less equipment and energy costs than a laser light source that emits light in the ultraviolet region. Therefore, it is necessary to use a laser light source that emits light in the visible range, such as an argon ion laser.However, currently commercially available PS plates are made of diazonium salts and quinonediazides, which are hardly sensitive to visible light. is used, making it unsuitable for realizing such technology, and there has been a desire to develop a lithographic plate material that can be made using visible laser light.

[Means for Solving the Problems] As a result of various studies conducted by the present inventors in order to meet the above-mentioned needs, the present inventors have developed a photopolymerization initiation system for addition-polymerizable compounds having ethylenically unsaturated double bonds. Based on this knowledge, we discovered that compositions containing xanthene or thioxanthene pigments exhibit excellent photosensitivity to visible light, and that cured polymer resins have excellent physical properties for printing. As a result, the present invention was completed.

The gist of the present invention is a lithographic plate comprising a support having a hydrophilic surface and a photosensitive resin layer provided on the surface of the support and containing an addition polymerizable compound having an ethylenically unsaturated double bond and a photopolymerization initiation system. In the printing plate material, the photopolymerization initiation system has the formula: In this case, there is a double bond between adjacent carbon atoms (indicated by a dotted line), and when Y is a nitrogen atom, there is a single bond between adjacent carbon atoms.), Z is Oxygen atom (in this case, there is a double bond between adjacent carbon atoms), lower alkoxy group or lower alkanoyloxy group, R group is lower alkyl group, hydroxy lower alkyl group, lower alkoxy lower alkyl group, di-lower Alkylamino lower alkyl group or aryl group, R2 is lower alkoxy group or di-lower alkylamino group. Note that Z and R1 may also be used. ] The plate material is sensitized to visible light and is characterized by being a xanthene or thioxanthene dye represented by the following.

[Function] There are no particular restrictions on the support as long as it has a hydrophilic surface and good adhesion to the photosensitive resin layer, but it is usually made of aluminum, zinc, nickel, stainless steel, etc. A metal plate is used.

The photosensitive resin layer provided on the hydrophilic surface of the support contains as essential components an addition polymerizable compound having an ethylenically unsaturated double bond (hereinafter referred to as "double bond-containing compound") and a photopolymerization initiation system. Contains.

The double bond-containing compound is a monomer having an ethylenically unsaturated double bond 1, or a side chain or a main chain, which is cured by addition polymerization under the action of a photopolymerization initiation system, resulting in substantial insolubilization. It is a polymer having an ethylenically unsaturated double bond, and one having a boiling point of 100° C. or higher is generally preferred.

Specific examples include unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds, unsaturated carboxylic acids and polycarboxylic acids, and aliphatic polyhydroxy compounds. Examples include esters obtained by an esterification reaction with polyhydric hydroxy compounds such as group polyhydroxy compounds and aromatic polyhydroxy compounds.

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, and maleic acid. Aliphatic polyhydroxy compounds include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, neopentyl glycol, propylene glycol, dihydric alcohols such as 1,2-butanediol, trimethylolethane, trimethylolpropane, and glycerol. Examples include trihydric alcohols such as, tetrahydric or higher alcohols such as pentaerythritol and tripentaerythritol, and polyhydric hydroxycarboxylic acids such as dihydroxymaleic acid. Examples of aromatic polyhydroxy compounds include hydroquinone, resorcinol, cathe, kohl, and pyrogallol. Examples of polyhydric carboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, trimellitic acid, pyromellitic acid, benzophenonedicarboxylic acid, maric acid, fumaric acid, malonic acid, geltal acid, and adipic acid. , sebacic acid, tetrahydrophthalic acid, etc.

Specific examples of esters of aliphatic polyhydroxy compounds and unsaturated carboxylic acids include ethylene glycol diacrylate, triethylene glycol diacrylate, tetramethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and pentaerythritol. diacrylate,
Pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tripentaerythritol octaacrylate-1,
Acrylic acid esters such as glycerol diacrylate,
Triethylene glycol dimethacrylate, tetramethylene glycol dimethacrylate-1, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate-1, pentaerythritol dimethacrylate-1, pentaerythritol trimethacrylate, pentaerythritol Tetraacrylate, dipentaerythritol dimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, tripentaerythritol octamethacrylate, ethylene glycol dimethacrylate, 1.
Methacrylic acid esters such as 2-butanediol dimethacrylate and sorbitol tetramethacrylate, ethylene glycol shiitaconate, propylene glycol shiitaconate, 1,2-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol tri- Itaconate esters such as taconate, crotonate esters such as ethylene glycol dicrotonate, diethylene glycol dicrotonate, pentaerythritol tetracrotonate, ethylene glycol dimaleate-1, triethylene glycol dimaleate, penta There are maleic acid esters such as erythritol dimaleate. Examples of esters of aromatic polyhydroxy compounds and unsaturated carboxylic acids include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate-1, resorcin dimethacrylate,
Examples include pyrogallol triacrylate. The esters obtained by the esterification reaction of unsaturated carboxylic acids with polyhydric carboxylic acids and polyhydric hydroxy compounds are not necessarily single, but typical examples are shown below (however, Z' is an acryloyl group or is a methacryloyl group): Z'-QC2H4-00C-C6H4-Coo-C
2H40-Z 'z' -+oc2H4)T-00C
→CH2)7-Coo→C2H405z 'Z'-4
0C2H4)700cmCH=CH-Coo<2I(4
0)yZ IZ-QC2H4-00C-C6H4-Co
Examples of double bond-containing compounds used in the o-C2H4-OH invention include acrylamides such as acrylamide, ethylenebisacrylamide, hexamethylenebisacrylamide, ethylenebismethacrylamide,
Methacrylamides such as hexamethylene bismethacrylamide, diallyl phthalate, diallyl malonate, diallyl fumarate, allyl esters such as triallylisone annulate, divinyl adipate, divinyl phthalate,
Examples include vinyl-containing compounds such as ethylene glycol divinyl ether.

Polymers having ethylenically unsaturated bonds in their main chains include, for example, polyesters obtained by the polycondensation reaction of unsaturated dicarboxylic acids and dihydrogycyl compounds, and polyamides obtained by the polycondensation reaction of unsaturated dicarboxylic acids and diamines. etc. Examples of unsaturated dihydric carboxylic acids include maleic acid and fumaric acid. Polymers with ethylenically unsaturated bonds in their side chains are divalent carboxylic acids with unsaturated bonds in their side chains, such as itaconic acid, α-methyl itaconic acid, γ-methyl itaconic acid, propylidenesuccinic acid, α-ethylidene. Examples include polyesters obtained by a polycondensation reaction of glutaric acid, ethylidenemalonic acid, propylidenemalonic acid, etc. with a dihydroxy compound, and polyamides obtained by a polycondensation reaction of diamines. Also suitable are polymers obtained by a polymer reaction between a polymer having a reactive functional group such as a hydroxyl group or a methyl halide group in its side chain and an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, or crotonic acid. It can be used for Examples of polymers having functional groups having reactive activity include polyvinyl alcohol, copolymers of vinyl alcohol and vinyl acetate, copolymers of vinyl alcohol and acrylonitrile, styrene, vinyl chloride, vinylidene chloride, etc., polyepichlorohydrin, 2-
hydroxyethyl methacrylate and acrylonitrile,
Copolymers with methyl methacrylate, butyl methacrylate, styrene, vinylidene chloride, vinyl acetate, etc., polyethers obtained by reaction of epichlorohydrin and 2,2-bis(4-hydroxyphenyl)-propane,
Examples include poly(4-hydroxystyrene) and poly(N-methylolacrylamide).

Among the double bond-containing compounds described above, monomers of acrylic esters or methacrylic esters can be particularly preferably used.

As the photopolymerization initiation system, a xanthene or thioxanthene compound (1) is used. In the above formula (I), specific examples of the halogen atom represented by X include chlorine,
There are bromine, etc. Further, examples of the lower alkoxy group represented by Z include methoxy, ethoxy, propoxy, etc., and examples of the lower alkanoyloxy group include acetyloxy, propionyloxy, butyryloxy, etc. Further, specific examples of the lower alkyl group represented by R1 include methyl, ethyl, propyl, butyl, pentyl, hexyl, hebyl, octyl, nonyl, de-1cyl, etc., and specific examples of the hydroxy lower alkyl group include hydroxy. Methyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, etc., and specific examples of lower alkoxy lower alkyl groups include methoxymethyl, methoxyethyl, methoxypropyl, ethoxyethyl, ethoxypropyl, ethoxybutyl, propoxyethyl, propoxypropyl, etc. Specific examples of di-lower alkylamino lower alkyl groups include dimethylaminomethyl, dimethylaminoethyl, dimethylaminopropyl, diethylaminoethyl, diethylaminopropyl, diethylaminoethyl, etc. Specific examples of aryl groups include phenyl, xylyl, tolyl, naphthyl, etc. Specific examples of the lower alkoxy group represented by R2 include methoxy, ethoxy,
Specific examples of the di-lower alkylamino group include propoxy, dimethylamino, diethylamino, and the like. In addition, xanthene or thioxanthene dye (1
) are generally known substances in the literature.

In addition to the above-mentioned xanthene or thioxanthene dye (I), an appropriate photosensitivity accelerator may be added as necessary in order to further improve the sensitivity to light and complete curing in a shorter time. Specific examples of suitable photosensitizers include N-phenylglycine, 24,6-tris(trichloromethyl)-1,3,5-triazine, 2,4-diisopropylthioxanthone and p-dimethylaminobenzoic isopentyl ester. Examples include.

The ratio of photopolymerization initiator system (total of photosensitizer when used with xanthene or thioxanthene dye) to the ethylenically unsaturated double bonded gold compound is 1 part by weight of the former to oot~0 of the latter. .5 parts by weight, preferably 0
．． 0.005 to 0.15 parts by weight. The ratio of the xanthene or thioxanthene dye and the photosensitizer used is 10 parts by weight or less, preferably 0.2 to 2 parts by weight of the latter.
It may be parts by weight. When the proportion of the photopolymerization initiator and photosensitizer used is small, sufficient sensitivity cannot be obtained or a sufficient effect of increasing sensitivity cannot be expected.

If the usage ratio is too high, the cured film will have a low molecular weight,
This results in a decrease in film strength and printing durability.

Although this is not particularly necessary if the double bond-containing compound has a sufficient molecular weight or glass transition point to form a film, an organic polymeric substance is usually blended as a binder. Such binders have various purposes for improving compatibility, film-forming properties, developability, weldability, etc., and an appropriate type may be selected depending on the purpose. Specifically, for example, to improve water-based developability, acrylic acid copolymers, methacrylic acid copolymers, itaconic acid copolymers, partially esterified maleic acid copolymers, acidic cellulose modified substances having carboxyl groups in side chains, Polyethylene oquinide, polyvinylpyrrolidone, etc. are used, and to improve film strength and adhesion, polyethers of shrimp chlorohydrin and phenol A, soluble nylon, polyalkyl methacrylates and polyalkyl acrylates such as polymethyl methacrylate, etc. Alkyl methacrylate and acrylonitrile, acrylic acid, methacrylic acid, vinyl chloride, vinylidene chloride,
Copolymers with styrene, etc., copolymers with acrylonitrile and vinyl chloride, vinylidene chloride, vinylidene chloride, chlorinated polyolefins, copolymers with vinyl chloride and vinyl acetate, polyvinyl acetate, copolymers with acrylonitrile and styrene. Examples include copolymers of acrylonitrile and butadiene and styrene, polyvinyl alkyl ethers, polyvinyl alkyl ketones, polystyrene, polyamides, polyurethanes, polyethylene terephthalate isophthalate, and acetyl cellulose polyvinyl butyral. These binders are usually blended in an amount of 10 parts by weight or less, preferably 0.5 to 3 parts by weight, per 11 parts of the double bond-containing compound +ff.

In addition to the above-mentioned components, the photosensitive resin layer may further contain a thermal polymerization inhibitor, a colorant, a plasticizer, a surface protective agent, a lubricant, a coating aid, etc., if necessary.

Examples of thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, pyrogallol, catechol, 2,6-
Examples include di-t-butyl-p-cresol and β-naphthol. Examples of colorants include phthalocyanine pigments,
There are pigments such as azo pigments, carbon black, and titanium oxide, triphenylmethane dyes, azo dyes, and anthraquinone dyes. The amount of these thermal polymerization inhibitors and colorants added is 0.01 to 3% by weight of the thermal polymerization inhibitor and 0.001% of the colorant based on the total weight of the double bond-containing compound and the binder.
10% by weight is preferred. Examples of plasticizers include dioctyl phthalate, didodecyl phthalate, dibutyl phthalate, butylbenzyl phthalate, triethylene glycol cipacrylate, dimethyl glycol phthalate,
These include tricresyl phosphate, dioctyl adipate, dibutyl adipate, dibutyl sebacate, dibutyl maleate, triacetylglycerin, etc., and can be blended in an amount of 5% by weight or less based on the total weight of the double bond-containing compound and binder.

In order to form the photosensitive resin layer, the composition containing the above-mentioned essential components and optional components may be coated on the support as it is or dissolved in a suitable solvent, and then dried. Examples of solvents include methyl ethyl ketone, acetone, cyclohexanone, ethyl acetate, butyl acetate, amyl acetate, ethyl propionate, toluene, xylene, benzene, monochlorobenzene, chloroform, carbon tetrachloride, trichloroethane, trichloroethane, dimethylformamide, methyl cellosolve, ethyl cellosolve. , tetrahydrofuran, pentoxone, methanol, ethanol, propatool, etc.

There is no particular limit to the thickness of the photosensitive resin layer, but in view of its use as a lithographic printing plate, it is desirable to make it as thin as possible within the limits of image formation, and is usually 0.5 to 7μ.
The film thickness is preferably about 1 to 3 μm.

Note that the photosensitive resin layer may further be subjected to known techniques for preventing adverse effects such as a decrease in sensitivity and deterioration of storage stability due to oxygen. For example, a peelable transparent cover sheet may be provided on the photosensitive layer, or a coating layer made of a waxy substance having low oxygen permeability, a water-soluble or alkali water-soluble polymer, or the like may be provided.

The photosensitive resin layer of the lithographic plate material of the present invention thus obtained can be used for carbon arc, high pressure mercury lamp, xenon lamp, metal halide lamp, fluorescent lamp, tungsten lamp, argon ion laser, helium cadmium laser, krypton laser, etc. It can be cured using a general-purpose light source such as a laser that includes ultraviolet rays and visible light of 180 nm or more, but in particular, by irradiating a laser beam to simultaneously form an image and cure it, it has lipophilic properties.
It is possible to efficiently produce a lithographic printing plate with excellent printing durability. Note that development after irradiation may be carried out using an appropriate developer capable of dissolving the photosensitive resin layer, depending on the composition of the photosensitive resin layer.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Preparation of lithographic printing plate 1.09% of methyl methacrylate/methacrylic acid copolymer (BR-77 manufactured by Mitsubishi Rayon) was mixed with 11% of methyl ethyl ketone.
After dissolving in 0 g, 1. pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry) was added to this. A first liquid is obtained by dissolving og. Thioxanthene color f: (1:A=
S; X=I-r; Y=C; Z”OCtl-[5;
R'=CaHs;R'=H) 60119, N-phenylglinone 60 shoulder 9, and 3 mg of methoquinone (p-methquinphenol) are dissolved in 3 g of methyl cellosolve to obtain a second solution. The second liquid was added to the first liquid and stirred well to obtain a photosensitive liquid.

The photosensitive solution was applied to a grained and anodized aluminum support using a bar coater to a coating weight of 2 g/m'' and dried at 60°C for 3 minutes. 5% polyvinyl alcohol (saponification degree 88%, polymerization degree 5
00) An overcoat layer was provided by applying an aqueous solution to obtain a lithographic plate material.

Sensitivity measurement Kodak Step Tablet No. 2 (21 steps)
' and the above lithographic plate material,
Light with a wavelength of around 490 nm (light intensity: 4° OmW/cm) extracted from a xenon lamp (USHIO, 150 W) through a filter was irradiated from above for 10 seconds.

When developed with a developer (10 parts by weight of anhydrous sodium carbonate, 50 parts by weight of butyl cellosolve and 3 parts by weight of an activator dissolved in 1000 parts by weight of water), the number of photocured stages was 11. From now on, this lithographic plate material is I+
It has become clear that image formation is possible with an exposure amount of around nJ/cm''.

Laser plate making and printing The laser beam (488
The lithographic plate material was cylindrical scanned (1000 rpm, 600 lines/1 nch) while modulating the wavelength (nm) with a modulator. Next, this was developed with the developer described above and desensitized with gum arabic. When offset printing was performed using this printing plate, up to 500,000 copies of printed matter could be obtained without any problems.

Example 2 As a thioxanthene dye (1: A=O;
Q: Y=N; Z=0; R'=CtHsO(CHt
)3; A lithographic plate material was obtained in the same manner as in Example 1 except that 60 mg of R2=N(Cd(s)t) was used. Example 1
When the sensitivity was measured under the same conditions as above, the number of photocured stages was 11. From now on, this lithographic plate material is ln+
It has become clear that image formation is possible with an exposure amount of around J/cm''.

Next, laser platemaking was performed using the above planographic plate material under the same conditions as in Example 1, and offset printing was performed using the obtained printing plate, and there was no problem at least up to 500,000 sheets. I was able to obtain a printed copy.

Example 3 2.4°6- instead of 601g of N-phenylglycine
A lithographic plate material was obtained in the same manner as in Example I except that tris(trichloromethyl)-1,3,5-triazine 60jy was used. When sensitivity was measured under the same conditions as in Example 1, the number of photocured stages was 11. From this, it was revealed that this lithographic plate material can form an image with an exposure amount of around 1 mJ/cm2.

Next, laser platemaking was performed using the above planographic plate material under the same conditions as in Example 1, and offset printing was performed using the obtained printing plate, and there was no problem at least up to 600,000 sheets. I was able to obtain a printed copy.

Example 4 Methyl methacrylate/methacrylic acid copolymer (BR,
-77) Lithography was carried out in the same manner as in Example J, except that 0 g of a partially methyl cellosolve hafesterized product of styrene/maleic acid copolymer (molecular weight approximately 70,000, acid value 80) was used in place of 1.09. A printing plate material was obtained.

When sensitivity was measured under the same conditions as in Example 1, the number of photocured stages was 10. From this, it was revealed that this lithographic plate material can form an image with an exposure amount of about 1.0 to I, 5 mJ, 7 cm2.

Next, laser platemaking was performed using the lithographic plate material described in Section 2 under the same conditions as in Example 1, and offset printing was performed using the obtained printing plate. I was able to obtain a printed product without.

[Effects of the Invention] The lithographic plate material of the present invention contains a xanthene or thioxanthene dye (1
), and as a result, image formation and curing can be achieved simultaneously without using a negative.
A lithographic printing plate can be manufactured efficiently. Furthermore, the cured resin layer of the obtained lithographic printing plate generally exhibits good lipophilicity and printing durability.

Patent applicant Nippon Paint Co., Ltd. Agent Patent attorney Aoyama Aoyama and one other person Procedural amendment,
(Mutsumi) September 17, 1985 ＼

Claims (1)

[Claims] 1. From a support having a hydrophilic surface, a photosensitive resin layer provided on the surface containing an addition polymerizable compound having an ethylenically unsaturated double bond, and a photopolymerization initiation system. In the lithographic plate material, the photopolymerization initiation system has the formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, A is an oxygen atom or a sulfur atom, Atoms (However, if Y is a carbon atom, there is a double bond between adjacent carbon atoms (indicated by a dotted line), and if Y is a nitrogen atom, there is a double bond between adjacent carbon atoms. is a single bond), Z is an oxygen atom (in this case, there is a double bond between adjacent carbon atoms), a lower alkoxy group or a lower alkanoyloxy group, R^1 is a lower alkyl group, a hydroxy lower The alkyl group, lower alkoxy lower alkyl group, di-lower alkylamino lower alkyl group or aryl group, R^2 is a lower alkoxy group or di-lower alkylamino group. In addition, Z and R^1 together are -Z-
As R^1-, there are ▲numerical formulas, chemical formulas, tables, etc. ▼ may also be expressed. ] A plate material that is sensitive to visible light and is characterized by being a xanthene or thioxanthene dye represented by the following. 2. Claim 1 in which the photopolymerization initiation system contains a photosensitizer in addition to a xanthene or thioxanthene dye
Plate materials listed in section. 3. The plate material according to claim 2, wherein the photosensitizer is N-phenylglycine. 4. The plate material according to claim 2, wherein the photosensitizer is 2,4,6-tris(trichloromethyl)-1,3,5-triazine. 5. The plate material according to claim 2, wherein the photosensitizer is 2,4-diisopropylthioxanthone and p-dimethylaminobenzoic acid isopentyl ester. 6. The plate material according to claim 2, wherein the ratio of the xanthene or thioxanthene dye and the photosensitizer is 1 part by weight of the former to 10 parts by weight or less of the latter. 7. The plate material according to claim 1, wherein the addition-polymerizable compound having ethylenically unsaturated double bonds has at least two ethylenically unsaturated double bonds in one molecule. 8. The plate material according to claim 7, wherein the addition-polymerizable compound having an ethylenically unsaturated double bond is a substance having a boiling point of 100°C or higher. 9. Claim 1, wherein the ratio of the addition-polymerizable compound having an ethylenically unsaturated double bond and the photopolymerization initiation system is 1 part by weight of the former to 0.001 to 0.5 part by weight of the latter.
Plate materials listed in section. 10. The plate material according to claim 1, wherein the photosensitive resin layer has a thickness of 0.5 to 7μ. 11. The plate material according to any one of claims 1 to 10, wherein the photosensitive resin layer further contains a binder. 12. The plate material according to claim 11, wherein the amount of the binder does not exceed 10 parts by weight per 1 part by weight of the addition-polymerizable compound having an ethylenically unsaturated double bond.