JPH04204450A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain a photosensitive compsn. having high sensitivity and satisfactory chemical resistance and fit for UV ink by incorporating o- naphthoquinonediazidosulfonic ester and a copolymer resin having specified structural units and structural units derived from vinylpyrrolidone. CONSTITUTION:The o-naphthoquinonediazidosulfonic ester and a copolymer resin having structural units represented by formula I (where each of R1 and R2 is H or alkyl) and structural units derived from vinylpyrrolidone are incorporated to obtain a photosensitive compsn. having superior resistance to processing chemicals, proof against processing chemicals used for printing with UV ink and having improved printing resistance and sufficiently high sensitivity.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a photosensitive composition suitable for use in a photosensitive lithographic printing plate, and more particularly, to a photosensitive composition suitable for use in a lithographic printing plate having UV ink suitability. The present invention relates to photosensitive compositions that can be used.

[Background of the Invention] A photosensitive lithographic printing plate has an ink-receptive photosensitive layer provided on a hydrophilic support. For example, in a positive photosensitive lithographic printing plate, an ink-receptive photosensitive layer is provided on a hydrophilic support. An ink-receptive photosensitive layer is formed which is solubilized by mist of actinic rays. When the photosensitive layer of such a positive-working photosensitive lithographic printing plate is subjected to imagewise exposure and then developed, the photosensitive layer in the exposed areas is removed and the surface of the hydrophilic support is exposed, while the photosensitive layer in the unexposed areas is removed. remains on the support to form an ink-receiving layer.

In planographic printing, the difference in properties is utilized in that the exposed areas are hydrophilic and the unexposed areas are lipophilic.

In recent years, ultraviolet curable UV inks have been used as planographic printing inks, and there has been a demand for photosensitive planographic printing plates that are suitable for UV inks.

As a photosensitive composition for obtaining a photosensitive lithographic printing plate having UV ink suitability, a composition using a polymeric substance having an N-(sulfamoyl-substituted phenyl)carbamoyl group as a binder is disclosed in JP-A-2-866. Are listed. However, the above photosensitive compositions do not have sufficient solubility in aqueous alkaline developers, require a long time for printing, and have problems in chemical resistance.

[Object of the Invention] Therefore, the object of the present invention is to provide a photosensitive composition that is highly sensitive, has good chemical resistance, and is suitable for UV inks.

[Structure of the Invention] The above object is characterized by containing a copolymer resin having an 0-naphthoquinonediazide sulfonic acid ester, a structural unit represented by the following general formula [1], and a structural unit derived from vinylpyrrolidone. This was achieved using a photosensitive composition.

General formula [1] %Formula% In the formula, R1 and R2 each represent a hydrogen atom or an alkyl group.

The present invention will be explained in detail below.

Examples of the 0-naphthoquinone diazide sulfonic acid ester used in the present invention include ester compounds of 0-naphthoquinone diazide sulfonic acid and polycondensation resins of phenols and aldehydes or ketones.

Examples of the above phenols include phenol, 0-
Cresol, m-cresol, p-cresol, 3.5
- Monohydric phenols such as xylenol, carvacrol, and thymol, dihydric phenols such as catechol, resorcinol, and hydroquinone, and trihydric phenols such as pyrogallol and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, and furfural. Preferred among these are formaldehyde and benzaldehyde. Further, examples of the above ketone include acetone and methyl ethyl ketone.

Specific examples of polycondensation resins include phenol/formaldehyde resin, m-cresol/formaldehyde resin, m-, p-mixed cresol/formaldehyde resin, resorcinol/unzaldehyde resin, and pyrogallol/formaldehyde resin.
Examples include acetone resin.

In the above 0-naphthoquinonediazide sulfonic acid ester, the condensation rate of 0-naphthoquinonediazide sulfonic acid with respect to the OH group of the phenol (reaction rate with respect to one OH group) is preferably 15 to 80%, more preferably 20%.
~45%.

Furthermore, as the O-naphthoquinone cyasitosulfonic acid ester used in the present invention, O-naphthoquinonediazide sulfonic acid ester described in JP-A-58-43451 can be mentioned.

More specifically, J. Kosar
Author: “Light Sensitive Systems”
339-352 (1965), John Viley & Sons, Inc.
) and double, --x Soupee” 7t rest (W, S,
De Forest) “Photoresist” (“P
photoresist”) Volume 50 (1975)
1,2-naphthoquinonediazide-4, described in McGrav-Hill, et al.
-sulfonic acid phenyl ester, 1,2-naphthoquinonediazide-5-sulfonic acid phenyl ester, 1,2-
Naphthoquinonediazide-4-sulfonic acid cyclohexyl ester, 1,2-naphthoquinonediazide-5-sulfonic acid cyclohexyl 51 ester, 1-(1,2-naphthoquinone 2-di-5-sulfonyluoquine)-3,5-
Methylvirazole, 1,2-naphthoquinonediacid-4-sulfonic acid-4'-hydroxydiphenyl-4'
-Azo β-naphthol ester, 2'-(1,2
-naphthoquinonecyato-4-sulfonyloxy)-1
-Hydroxy-anthraquinone, 1,2-naphthoquinonediazide-4-sulfonic acid-2,4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-
4-sulfonic acid-2,3゜4-trihydroxybenzophenone ester, 1゜2-naphthoquinonediazide-4-
2 moles of sulfonic acid chloride and 4,4'-dihydroxy-
Condensate of 1 mole of 1,1'-diphenylsulfone, 1.2
-Naphthoquinonediazide-condensate of 1 mol of 4-sulfonic acid chloride and 1 mol of purbrogarin, 1,2-naphthoquinonediazide-5-sulfonic acid-4'-hydroxydiphenyl-4'-azo-β-naphthol ester, 2'-
(1,2-naphthoquinonediazide-5-sulfonyloxy)-1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-5-sulfonic acid-2,4-dihydroxybenzophenone ester, 1,2-naphthoquinonediazide-5-sulfone acid-2,3'',' 4-1-dihydroxybenzophenone ester, 2 moles of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 4.4'
A condensate of 1 mole of -dihydroxy-1,1'-diphenylsulfone, a condensate of 1 mole of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of purpurogalin, and the like. - Naphthoquinonediazide sulfonic acid ester can be exemplified.

Also, Special Publication No. 37-1953, No. 37-3627,
No. 37-13109, No. 40-26126, No. 40
-3801, 45-5604, 45-2734
No. 5, No. 51-13013, JP-A-48-9B575
0-naphthoquinonediazide sulfonic acid esters described in Japanese Patent No. 48-[13802 and No. 48-83803] can also be mentioned.

Among the above 0-naphthoquinone diazide sulfonate esters, 0- obtained by reacting 1,2-naphthoquinone diazide sulfonyl chloride with pyrogallol acetone condensation resin or 2,3,4-trihydroxybenzophenone
Particularly preferred are naphthoquinonediazide sulfonic acid esters.

Used in the present invention. - As the naphthoquinone diazide sulfonic acid ester, each of the above compounds may be used alone, or two or more thereof may be used in combination.

The proportion of 0-naphthoquinonediazide sulfonic acid ester used in the present invention in the photosensitive composition is 5 to 60%.
% by weight is preferred, particularly preferably 10-50% by weight
It is.

Next, a copolymer resin having a structural unit represented by the general formula [1] and a structural unit derived from vinylpyrrolidone (hereinafter referred to as the binder resin of the present invention) will be described.

In the general formula [1], the alkyl group represented by R, R2 is preferably a lower alkyl group, such as a methyl group or an ethyl group.

Preferred examples of R and R2 are a hydrogen atom and a methyl group.

Specific examples of the structural unit represented by general formula [I] are shown below.

-al-b YunCH gate-CH+-(CH2CH square c=o　　　　　c=.

I Ctl, (, H.

*CHxC+−云CH,−C← c=o　　　　　c=.

(==Q　　　　　　　　c=.

□ I, l h C) l, CH3 or less The binder resin of the present invention has a structural unit represented by the general formula [1] and a structural unit derived from vinylpyrrolidone, but the binder resin of the above structural unit has It may also have one or more structural units derived from other monomers (hereinafter referred to as copolymer component structure intermediate).

Monomers that lead to these copolymer component structural units include ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene; styrene, α
- Styrenes such as methylstyrene, p-methylstyrene, p-talolostyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate,
Esters of a-methylene aliphatic monocarboxylic acids such as phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, and ethyl ethacrylate;
- Rils, amides such as acrylamide, anilides such as acryloanilide, p-chloroacryloanilide, m-nitroacryloanili 11, m-methogyne acryloanilide.

Vinyl acetate, vinyl propionate, vinyl henzoate,
Vinyl esters exclusively for vinyl butyrate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl, ether, β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanite, 1-methyl-1-methoxyethylene, 1.
]-dimethoxyethylene, 1,2-dimethoquinoethylene, 1-dimethoxyethylene, 1-dimethoxyethylene, 1-methyl-1-nitroethylene, and other enane derivatives.

N-vinylpyrol, N-vinylcargusol, N-
N-vinyl compounds such as vinyl indole, N-vinylvirolone, and N-vinylpyrrolidone.

Other vinyl monomers may also be used. These vinyl monomers exist in polymer compounds with a structure in which an unsaturated double bond is cleaved.

Among the above-mentioned monomers, esters of aliphatic monocarboxylic acids and nitriles are preferred because they exhibit excellent performance for the purpose of the present invention.

The 11th structure of these is the one of the present invention! - They may be bonded in either a block or random state in the inner resin.

Typical examples of the 7-inner resin of the present invention are shown below. In addition, in the following, M w is a weight average molecular weight, M n is a number average molecular weight, s, , Q.

m and n indicate mol% of each structural unit.

Margin below a-2) m'n'o"ri5: 25: 50b-
1) CH3 (CH2-C←recTo-CH←+CH2-CH←"
Child CH2CH? .

1 1 l
IMw-3,2XIO' Mw/Mn76.5
m: n: Q: k-30:35:30: 5Mw
-4,0XLO'Mw/Mn-7,0m'n:
Q: k-15:15:40:30cm1) lh ■ m'n': a = 25: 25: 50C
-2) CH2 canter m:. :. Wrinkle 20: 2tl: e.

d-1) L d-2) H3 Mvv-2,1XlO' Mw/Mn -6,7m
'n: Q: k-25:25:40:10Mw-
3,1X10'Mw/Mn-8,0m'n:
Q: k-35:30:30: 5f-1) BI CI (3 g-1) CH3CH3CH3 h-1) CH3CL An ethylenically unsaturated monomer capable of deriving a structural unit and vinylpyrrolidone are added, if necessary, with the other monomers mentioned above, with or without a polymerization initiator. Copolymerization can be carried out with or without using a melting technique.

At this time, the molecular weight and the molar ratio of each structural unit can be set over a wide range by varying the charging molar ratio of each monomer and the polymerization conditions.

However, in order to effectively serve the purpose of the present invention, the weight average molecular weight must be set to 5. OX 103~1.0×10
5. Ox 103~4.0
x104 is preferred. Furthermore, the molar content of the structural unit represented by the general formula [I] and vinylpyrrolidone is preferably at least 10 mol% each. More preferably, it is 20 to 40 mol%.

Preferably it is 50 to 85% by weight.

Moreover, the above molecular weight was measured by GPC (Kervermination cyclomatography method).

The photosensitive composition of the present invention can contain a known alkali-soluble resin. Examples of alkali-soluble resins include novolac resins, such as phenol-formaldehyde resins, cresol-formaldehyde resins, phenol-modified xylene resins, and polyhydroxystyrene, but such alkali-soluble polymer compounds account for 40% by weight of the total composition. It is used in the following amounts.

In addition to the materials described above, the photosensitive composition of the present invention can contain other additives as necessary. Plasticizers include various low-molecular compounds such as phthalate esters, triphenyl phosphates, maleate esters, and coating properties improvers include surfactants such as fluorine surfactants and ethyl cellulose polyalkylene ether. Examples include nonionic activators and the like, as well as printout materials for forming visible images upon exposure to light. The printout material consists of a compound that generates acid or free radicals when exposed to light, and an organic dye that changes its color tone by interacting with it. 0-Naphthoquinonediazide-4-sulfonic acid halide described in Publication No. 50-38209, JP-A-5
Trihalomethyl-2-pyrone and trihalomethyl-triazine described in Publication No. 3-36223, JP-A-5
Ester compounds of O-naphthoquinone cyato-4-sulfonic acid chloride and phenols or anilines having an electron-withdrawing substituent described in Japanese Patent Application Laid-Open No. 55-77742 Examples include halomethyl-vinyl-oxadiazole compounds and diazonium salts.

Among cholera, halomethyl-vinyl-oxadiazole compounds are preferable, and in particular, halomethyl-vinyl-oxadiazole compounds are preferable, and in particular, compounds containing an oxygen-containing heterocyclic group such as the henzofuryl group described in JP-A-60-138539 are used directly or via a vinyl group. More preferred is a 2-halomethyl-1,3,4-oxadiazole compound having the 5-position.

Further, as the organic dye, for example, Victoria Pure Blue BOH [Hodogaya Chemical Co., Ltd.], Oil Blue #6
03 E Orient Chemistry], Patent Pure Blue [
Made by Sumitomo Mikuni Chemical], Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Clean,
Triphenylmethane type, diphenylmethane type represented by erythrosin B1 basic fukunun, malachite green, oil red, m-cresol purple, rhodamine B1 auramine, 4-p-diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenyl acetanilide, etc. Examples include oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based, and anthraquinone-based dyes. Among these, triphenylmethane dyes are preferred.

Further, a sensitizer for improving sensitivity can also be added to the photosensitive composition of the present invention. As the sensitizer, gallic acid derivatives described in JP-A-57-118.237, 5-membered cyclic acid anhydrides as described in JP-A-52-80022, e.g. Phthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
Examples include maleic anhydride, succinic anhydride, virometic acid, itaconic acid, etc., and 6-membered cyclic acid anhydrides such as those described in JP-A-58-11932, such as glutaric anhydride and its derivatives. . Among these, cyclic acid anhydrides are preferred, and 6-membered cyclic acid anhydrides are particularly preferred.

A positive-working photosensitive lithographic printing plate can be formed by dissolving the photosensitive composition of the present invention in a solvent that dissolves each of the above-mentioned components, and applying and drying the solution on the surface of a suitable support. Examples of solvents that can be used include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, and methyl ethyl ketone. These solvents may be used alone or in combination of two or more.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating, etc. can be used.

Examples of the support on which the photosensitive layer using the photosensitive composition of the present invention is provided include metal plates such as aluminum, zinc, copper, and steel, and metal plates plated or vapor-deposited with chromium, zinc, copper, nickel, aluminum, iron, and the like. Examples include metal plates, paper, plastic films, paper coated with resin, paper covered with metal foil such as aluminum, and plastic films treated to make them hydrophilic. Among these, aluminum plates are preferred.

When an aluminum plate is used as a support, it is preferably subjected to surface treatments such as graining, anodizing, and, if necessary, sealing. Known methods can be applied to these treatments.

Examples of the graining treatment include a mechanical method and an electrolytic etching method. Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a Hough polishing method.

The various methods described above can be used alone or in combination depending on the composition of the aluminum material. Preferred is electrolytic etching.

Electrolytic etching is carried out in a bath containing one or a mixture of two or more inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid. After the graining treatment, if necessary, desmut treatment is performed with an aqueous alkali or acid solution, neutralized, and washed with water.

The anodic oxidation treatment is performed by electrolyzing using an aluminum plate as an anode using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid, etc. as an electrolytic solution. The amount of anodic oxide film formed is 1 to 50 g/dr
rf is suitable, preferably 10-40mg/d
It is rd. The amount of anodized film can be determined by, for example, applying an aluminum plate to a phosphoric acid chromic acid solution (85% phosphoric acid solution: 35 ml
(Prepared by dissolving chromium oxide (Vj)+20g in 1g of water) to dissolve the oxide film, and it is determined by measuring the change in weight of the plate before and after the film is dissolved.

Specific examples of the sealing treatment include hot water treatment, steam treatment, sodium silicate treatment, and dichromate aqueous solution treatment. In addition, the aluminum plate support may be subjected to subbing treatment using an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconate.

In addition, in general, when contact baking a film original onto a photosensitive lithographic printing plate, the printing frame is vacuumed, or the vacuum adhesion is improved. Can be applied to printing plates. Methods for improving vacuum adhesion include mechanically creating unevenness on the surface of the photosensitive layer, scattering solid powder on the surface of the photosensitive layer,
A method of providing a matte layer on the surface of a photosensitive layer as described in JP-A-50-125805, and JP-A-50-125805.
Examples include a method of heat-sealing a solid powder onto the surface of a photosensitive layer, as described in Japanese Patent No. 5-12974.

The photosensitive lithographic printing plate to which the photosensitive composition of the present invention is applied can be used in the same manner as conventionally used. For example, an alkali ring (
Developed with liquid, leaving only the unexposed part on the surface of the support,
Forms a positive relief image.

Examples of alkaline developers include sodium hydroxide,
Examples include aqueous solutions of alkali metal salts such as potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate, sodium diphosphate, and sodium triphosphate.

The concentration of the alkali metal salt is preferably 01 to 10% by weight.

In addition, an anionic surfactant may be added to the developer as necessary.
Amphoteric surfactants and organic solvents such as alcohols can be added.

[Examples] Hereinafter, the present invention will be explained by examples, but the present invention is not limited thereto.

Example 1 [Synthesis of exemplary binder resin (a-1)] Synthesis of N-(p-aminosulfonylphenyl)acrylamide 300 g of p-aminobenzenesulfonamide, 2 g of hydroquinone monomethyl ether, 32 g of acetone, and 160 g of pyridine were mixed, and a cryogen was added. The mixture was cooled from the outside using a vacuum cleaner, and when the internal temperature had dropped to -10°C, 170 g of acrylic acid chloride was added dropwise with stirring. Adjust the dropping rate so that the reaction temperature is below 0°C, and after the completion of the dropping, add 2 at 0 to 3°C.
Stir for hours.

Next, after stirring at 25°C for 2 hours, the reaction solution was concentrated to 1/3, poured into dilute hydrochloric acid (pH approximately 1.0), and the resulting precipitate was suction-filtered to form a white solid. I got it.

This white solid was dissolved in 1 p of warmed methanol, 1 p of a 5% aqueous sodium carbonate solution was added, and the mixture was stirred at 40° C. for 30 minutes.

This dark red solution was then poured into 5% hydrochloric acid 42 to form a precipitate, which was filtered with suction and dried to give a white solid. This was recrystallized from a mixed solvent of ethanol and water to obtain 300 g of N-(p-aminosulfonylphenyl)acrylamide.

Obtained N-(p-aminosulfonylphenyl)acrylamide 89.2 g, vinylpyrrolidone 89.72 g
g, methyl methacrylate 80. ]Og and α.

13.56 g of 4'-azobisisobutyronitrile was added to 300 ml of acetone/methanol (1:1) mixed solvent.
After dissolving in the solution and purging with nitrogen gas, it was heated at 80° C. for 4 hours to obtain a polymer solution. This polymer solution was poured into 32 ml of 5% hydrochloric acid, and the resulting white precipitate was filtered and dried to obtain 230 g of exemplified binder resin (a-1).

Similarly, exemplary binder resins (e-1) and (h-1)
was synthesized.

After degreasing an aluminum plate with a thickness of 0.24°C in a 5% aqueous sodium hydroxide solution, it was treated in a 0.3M nitric acid aqueous solution at a temperature of 30°C, a current density of 50 A/dr, and a treatment time of 30 seconds. Electrolytic etching treatment was performed.

Next, a desmut treatment was performed with a 5% aqueous sodium hydroxide solution, and then an anodization treatment was performed in a sulfuric acid solution. When the amount of anodic oxide film was measured using the method described above, it was found to be 20 mg.
/ d rrr was there. Next, it was immersed in a hot aqueous solution at 90°C for pore sealing treatment.

The aluminum support thus obtained was coated with photosensitive liquid (I), photosensitive liquid (■), photosensitive liquid (■), and photosensitive liquid (comparison) having the following compositions using a rotary coater, and
It was dried at 0° C. for 4 minutes to obtain photosensitive lithographic printing plate samples 1 to 4 having a film thickness of 24 μg/drrr.

Photosensitive liquid (1) Ester compound of trihydroxybenzophenone and naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid chloride 3.6g Above-mentioned binder resin (a-1) 7.4g Victoria Pure Blue B OHO, 084g 2-Trichloromethyl-5-[β-(2-benzofuryl)vinyl]-1,3,4-oxadiazole O, 126g Methyl cellosolve 100-ml Photosensitive solution (II) Trihydroxybenzophenone and naphthoquinone-( Ester compound with 1,2)-diazide-(2)-5-sulfonic acid chloride 3.6g The above-mentioned binder resin (e-1) 7.4g Victoria Pure Blue B OH0,084g 2-Trichloromethyl-5-[β -(2-Benzofuryl)vinyl] -1,3,4-oxadiazole O, 128g Methyl cellosolve 100ml Photosensitive liquid (
m) Trihydroxybenzophenone and naphthoquinone-(1,2)-diazide-(2)-5-
Ester compound with sulfonic acid chloride
3.6g of the above binder resin (h-1)
7.4g Victoria Pure Blue B OH0.08
4+r2-Trichloromethyl-5-[β-(2-benzofuryl)vinyl]- 1,3,4-oxaneazole 0.126g Methyl cellosolve 100ml Photosensitive solution (comparison) Trihydroxybenzophenone and naphthoquinone-(1,2)- Ester compound with diazide-(2)-5-sulfonic acid chloride 3.6g Binder resin for comparison (polymer compound b described in JP-A-2-866) 7.4g Victoria Pure Blue B OH0,084g 2-trichloromethyl -5-
[β-(2-Benzofuryl)vinyl]-1,3,4-oxadiazole 0.126 g Methyl cellosolve l OOm + Samples 1.2.3 and 4 thus obtained were coated with a step tablet for sensitivity measurement (Eastman・Kodak No. 2
, a gray scale with a density difference of 015 and 21 steps) and a Bon original film were placed in close contact and exposed for 70 seconds at 80 ■ W/cd using a 2 kW metal halide lamp (manufactured by Iwasaki Electric Co., Ltd., Idol Fin 2000) as a light source. Next, development was performed at 25°C for 45 seconds using a 6-fold dilution of the positive PS plate developer "5DR-1" (manufactured by Konica Corporation), and the non-image areas were completely removed. A lithographic printing plate was obtained.

Sensitivity was evaluated based on the gray scale of the above-mentioned density difference of 015.21 steps, based on which step the image was completely developed (became clear).

In order to examine resistance to processing chemicals, durability against plate cleaner and washing oil, which are used as cleaning liquid to remove background stains that occur in non-image areas during printing, was investigated. The printing plate, on which an image with density differences on the above gray scale stages was formed, was immersed in stock solutions of FD plate cleaner (manufactured by Toyo Ink Co., Ltd.) and Uv plate cleaner (manufactured by Morohoshi Ink Co., Ltd.) at room temperature for 12 hours, and in the same manner. The image area was immersed for 10 minutes in the undiluted solution of UV plate cleaning solution Best Cure (manufactured by Toka Dye Chemical Co., Ltd.) and UV plate cleaning solution Tsurfit (manufactured by Clarei Sobrene Chemical Co., Ltd.), washed with water, and compared with the image area before immersion. The degree of erosion against treatment chemicals was measured.

The results of sensitivity and processing chemical resistance are shown in Table 1.

Table 1 In Table 1, There is only slight erosion in the A9 image area.

B: Erosion as above was observed, and the grains of the support under the photosensitive layer were slightly exposed.

C1 Same as above, significant erosion was observed, and the grains of the support of the photosensitive layer were completely exposed.

Add color to things.

From the results in Table 1, samples 1 to 3 of the present invention, in which the binder resin is a polymer having a structural unit represented by the general formula [I] and a structural unit derived from vinylpyrrolidone, are different from the comparative binder resin. UV than that used (sample 4)
It can be seen that it has excellent resistance to plate cleaners used when ink is used. Also, the sensitivity is
It is equivalent to that using a comparative binder resin, and there is no deterioration.

[Effects of the invention] The photosensitive composition of the present invention has excellent resistance to processing chemicals, and the lithographic printing plate using the photosensitive composition of the present invention can withstand processing chemicals used in UV ink printing and has increased stiffness resistance. do. Also,
The photosensitive composition of the present invention also has sufficient sensitivity.

Claims (1)

[Claims] A photosensitive material characterized by containing a copolymer resin having an o-naphthoquinonediazide sulfonic acid ester and a structural unit represented by the following general formula [I] and a structural unit derived from vinylpyrrolidone. Composition. General formula [I] ▲There are numerical formulas, chemical formulas, tables, etc.▼ In the formula, R_1 and R_2 each represent a hydrogen atom or an alkyl group.