JPH03219250A - Photosensitive composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive composition suitable for producing a photosensitive lithographic printing plate. More specifically, the present invention relates to a photopolymerizable photosensitive composition that can be developed with an aqueous alkaline developer and that can provide a lithographic printing plate with high printing durability.

[Conventional technology]

Conventionally, many image forming methods using photopolymerizable photosensitive compositions are known. For example, a photosensitive composition consisting of an ethylenically unsaturated compound capable of addition polymerization, a photopolymerization initiator, and, if necessary, an organic polymer bond, a diazo resin, a colorant, a stabilizer, etc., is prepared and then There is a known method for producing a photosensitive material provided with a layer of a photosensitive composition by coating it on a support without a solvent or by dissolving it in an organic solvent.

A cured relief image can be formed by imagewise exposing this photosensitive material to actinic light to cure the exposed areas and removing the unexposed areas using a developer.

Such photopolymerizable compositions have conventionally been used for forming various images such as photosensitive lithographic printing plates, photosensitive resin letterpress plates, screen printing plates, photoresists, and color proofs.

When the photopolymerizable composition is utilized as a photosensitive image forming layer passed through an aqueous alkali developable photosensitive lithographic printing plate, an alkali soluble or swellable organic polymeric binder is generally used in combination.

Examples of such organic polymer binders include addition polymers having carboxyl groups in side chains (e.g., copolymers of methacrylic acid and other vinyl compounds; partially esterified maleic acid copolymers, etc.); Addition polymers having an ethylenically unsaturated bond and a carboxyl group in 4111 (for example,
Polyvinyl acecool resins and modified products thereof (e.g. copolymers of allyl methacrylate and methacrylic acid), which are obtained by adding an oxirane ring-containing ethylenically unsaturated compound to a part of a carboxyl group-containing vinyl copolymer (e.g. copolymers of allyl methacrylate and methacrylic acid) , cyclic acid anhydride adducts; alkylphosphinic acid isocyanate adducts; isopropenylsulfonyl isocyanate adducts, etc.), polyurethane resins having carboxyl groups in their side chains, polyurethane resins having ethylenically unsaturated bonds and carboxyl groups in their side chains, etc. It has been known.

However, among these organic polymer binders having carboxyl groups in their side chains, although they can be developed with an aqueous alkaline developer, they have problems with compatibility with ethylenically unsaturated compounds capable of addition polymerization and photopolymerization initiators. Moreover, the rigidity resistance was not necessarily sufficient. In addition, when an organic polymer binder having a carboxyl group in the side chain is further introduced with an ethylenically unsaturated bond, the curing efficiency is improved and the stiffness resistance is improved to some extent, but the effect is insufficient and the opposite is true. There were also problems in that the developability with an aqueous alkaline developer was lowered and the storage stability was lowered.

[Problem to be solved by the invention]

Therefore, the present inventors have developed a photosensitive composition that, when used in a photosensitive lithographic printing plate, has excellent developability in an aqueous alkaline developer and can provide a lithographic printing plate with high printing durability. As a result of research into sexual compositions, the present invention was achieved.

[Means to solve the problem]

The present invention relates to a photosensitive composition characterized by containing an alkali-soluble or swellable polyester resin having a carboxyl group in its side chain, an ethylenically unsaturated compound capable of addition polymerization, and a photopolymerization initiator. .

As for the carboxyl group content in the present invention, it is preferable to select Keyaki so that the acid value of the polyester resin is 10 to 200. When the acid value of the polyester resin is less than 10, developability with an aqueous alkaline developer is insufficient, and when the acid value of the polyester resin exceeds 200, oil sensitivity and printing durability tend to decrease. It is not desirable because it is in

It is preferable that the polyester resin of the present invention contains a carbon-carbon unsaturated bond. The term "carbon-carbon unsaturated bond" refers to and includes both ethylenic and acetylenic bonds, with ethylenic bonds being preferred. carbon-
The content of carbon unsaturated bonds is polyester resin 1
It is preferable to select carbon-carbon unsaturated bonds in an amount of 0.1 equivalent or more and 5 equivalents or less with respect to 000 g. 0.1
If the amount is less than the equivalent, the effect of increasing stiffness resistance due to the introduction of carbon-carbon unsaturated bonds will be insufficient.

The polyester resin having a carboxyl group in the side chain used in the present invention can be synthesized by the following method (a) or (b).

(a) - A diol compound having a carboxyl group represented by formula (1) is reacted with a dicarboxylic acid or a derivative thereof.

(b) A diol compound and a dicarboxylic acid or a derivative thereof are reacted in excess of the diol component to synthesize a polyester resin having a hydroxyl group at the terminal, and then a tetracarboxylic dianhydride is reacted.

HOR+ CRz OH... (1) COOH (wherein, R, and R2 may be the same or different, and substituents (for example, alkyl, aryl, alkoxy, aralkyl, alkenyl, and hyalogeno bancha) represents a divalent aliphatic hydrocarbon having 1 to 20 carbon atoms which may have a substituent (for example, alkyl, aryl, alkoxy, amide and halogeno bancha are preferred). It represents an alkyl or alkenyl group having 1 to 8 carbon atoms, an aryl group having 6 to 15 carbon atoms, which may have one or more carbon atoms.] Examples of the diol compound having a carboxyl group represented by the general formula (1) include 2,2 -bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxyethyl)propionic acid, 2.2-bis(3-hydroxypropyl)propionic acid, 2.2-bis(2-hydroxypropyl)propion al, 2 .2-bis(hydroxymethyl)-na acid and the like.

In method (a), a diol compound having no carboxyl group can also be used in combination.

Examples of such diol compounds and diol compounds that can be used in the method (b) include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, neopentyl glycol, , 3-butylene glycol, 1,6-hexanediol, 2.2
．． 4-Trimethyl-1,3-bentanediol, L4
-bis-β-hydroxyethoxycyclohexane, cyclohexane dimetatool, tricyclodecane dimetatool, hydrogenated bisphenol A1 hydrogenated bisphenol F1 ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, bisphenol F Ethylene oxide adduct, propylene oxide adduct of bisphenol F, ethylene oxide adduct of hydrogenated bisphenol, propylene oxide adduct of hydrogenated bisphenol A, hydroquinone dihydroxyethyl ether, p-xylylene glycol, bis(2
-hydroxyethyl) inphthalate and the like. Examples of dicarboxylic acids or derivatives thereof that can be used in methods (a) and (b) include succinic acid, adipic acid, azelaic acid, sepatic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid,
Tetrabromphthalic acid, tetrachlorophthalic acid, 1.4
Examples include dicarboxylic acids such as -cyclohexanedicarboxylic acid, carboxynorbornaneacetic acid, 5-sodium sulfoisophthalic acid, 4-hydroxybenzylidenemalonic acid, and 3-hydroxyphthalic acid, their anhydrides, or ester derivatives thereof.

Further, examples of the tetracarboxylic dianhydride used in the method (b) include a compound represented by the following formula (2).

O (In the above formula (2), R represents a tetravalent organic group containing at least two carbon atoms.) The tetracarboxylic dianhydride used in the present invention includes pyromellitic dianhydride. , 3.3', 4.4'-benzophenonetetracarboxylic dianhydride, 3,3'4.4'-diphenyltetracarboxylic dianhydride, 2.3.7-naphthalenetetracarboxylic dianhydride, 1.4,5.8-Naphthalenetetracarboxylic dianhydride, 4.4'-sulfonylsiphthalic dianhydride, 2.2-bis(3,4-dicarboxyphenyl)brovannihydride, bis(3 ,4-
dicarboxyphenyl)ether dianhydride, 4.4'
-(3,3' (alkylphosphoryldiphenylene)-bis(iminocarbonyl)]cyphthalic dianhydride,
Aromatic tetracarboxylic dianhydrides such as adducts of hydroquinone diacetate and trimellitic anhydride, adducts of diacetyldiamine and trimellitic anhydride; 5- (
2,5-dioxotetrahydrofuryl)-3methyl-3
- Cyclohexene-1,2-dicarboxylic acid anhydride (manufactured by Dainippon Ink & Chemicals KK, trade name "Evicron B-44")
00j), butane-1,2,3,4-tetracarboxylic dianhydride, aliphatic or alicyclic tetracarboxylic dianhydride such as cyclopentane tetracarboxylic dianhydride.

Polyester resins having carboxyl groups in their side chains are usually prepared by means known in this field, for example
Polymerization Reaction Theory 9, Polycondensation” by Ogata, published by Kagaku Dojinsha, or JP-A-60-165646, US Patent 3.
It can be easily produced by the method described in Japanese Patent No. 622.320.

By method (a) or (b), a polyester resin containing a side chain carboxyl group is synthesized so as to have a terminal hydroxyl group, and a compound ( (hereinafter referred to as chain extender)
It is also possible to increase the molecular weight by reacting.

As a chain extender having a functional group that can react with a hydroxyl group,
For example, diaryl phthalate compounds, diaryl phthalate compounds, diaryl carbonate compounds, bis(N
-acyllactam) compounds, bis(N-acylimide)
compound, bisbenzoxazinone compound, polyisocyanate compound, bisoxacilone compound, bis(N-acylimidazole) compound, alkoxysilane compound,
There are compounds such as silanol compounds, furoxane compounds, bisaziridine compounds, polyisothiocyanate compounds, divinyl ether compounds, diketene acetal compounds, unsaturated cycloacetal compounds, and biscarbodiimide compounds.

A high molecular weight polyester resin can be easily synthesized by reaction with a chain extender, for example, by the method described in JP-A-60-191244.

Further, the polyester chain may have other bonds such as urethane, amide, ureido, and ether bonds.

The molecular weight of the polyester resin having a carboxyl group can take any value over a wide range, but in order to use it for the purpose of the present invention, the weight average molecular weight is 1.
000 to 150,000 is preferable, and the weight average molecular weight is 7.
000 to 60,000 is particularly preferred.

The carbon-carbon unsaturated bond that may be present in the polyester resin having a carboxyl group in the side chain of the present invention can be introduced by the following method (c), (d) or (e). It is.

(c) In the method (a) or (b) above, a diol compound having a carbon-carbon unsaturated bond is used in combination with the diol component.

(d) In the method (a) or (b) above, a dicarboxylic acid or a derivative thereof having a carbon-carbon unsaturated bond is used in combination with the dicarboxylic acid or a derivative thereof.

(e) A part of the carboxyl groups of the polyester resin having carboxyl groups synthesized by the method (a) or (b) above is reacted with a halogen compound or an epoxy compound having a carbon-carbon unsaturated bond.

(f) In the method (a) or (b), a hydroxycarboxylic acid or diol obtained by adding an epoxy compound having a carbon-carbon unsaturated bond to one or both sides of the dicarboxylic acid is used in combination.

Examples of the diol compound having a carbon-carbon unsaturated bond include glycerol α-monoallyl ether,
trimethylolpropane monoaryl) Lid-7-/lz
, pentaerythritol diallyl ether, N,N-diallyltartaric acid diamide, 2-butene-1,4-diol, 2-butyne-1,4-diol, and the like.

Examples of dicarboxylic acids or derivatives thereof having a carbon-carbon unsaturated bond include maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, hymic acid, p-phenylene diacrylic acid, m-phenylene diacrylic acid. , cinnamylidenemalonic acid, p-carboxycinnamic acid, ρ, p-chalcone dicarboxylic acid, or anhydride or ester derivative thereof.

Examples of the halogen compound or epoxy compound having a carbon-carbon unsaturated bond include allyl bromide, 2-butenyl bromide, 1-phenyl-1-propenyl-3-
Halogen compounds such as bromide, 2-bromoethylcinnamate, promonotyl styrene, propangyl bromide, bromo-2-butyne, and the above chlorine compounds; allyl glycidyl ether, 2-butenyl glycidyl ether, 1-
Examples include epoxy compounds such as phenyl-propenyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, glycidyl cinnamate, and propargyl glycidyl ether.

To the polyester resin having a carboxyl group or the polyester resin having a carboxyl group and a carbon-carbon unsaturated bond obtained as above, an ethylenically unsaturated compound capable of addition polymerization and a photopolymerization initiator are added,
If necessary, a diazo resin is added to prepare the photosensitive composition of the present invention.

As a photopolymerization initiator, for example, US Pat. No. 236766
α-carbonyl compounds described in US Pat. No. 1, acyloin ethers described in US Pat. No. 2,448,828, and α-hydrocarbon-substituted aromas described in US Pat. No. 2,722,512. Group acyloin compounds, multi-limbed quinone compounds described in U.S. Pat. No. 3,046,127, U.S. Pat. No. 3,549,367
The combination of triarylbiimidazole and p-aminophenyl ketone described in U.S. Pat. No. 42
Trihalomethyl- as described in No. 39850
S-triazine compounds, oxadiazole compounds described in U.S. Pat. No. 4,212,970, acridine and phenazine compounds described in U.S. Pat. No. 3,751,259, Japanese Patent Publication No. 51-48516
Examples include benzothiazole compounds described in the above publication, and the amount used is 0.5% based on the solid content of the composition.
A range of 20% by weight is preferred.

Addition-polymerizable ethylenically unsaturated compounds are monomers or oligomers having a boiling point of 100°C or higher at normal pressure and having at least one, preferably two or more addition-polymerizable ethylenically unsaturated groups in one molecule. It is. Examples of such 7mers or oligomers include polyethylene glycol mono(meth)acrylate (hereinafter, methacrylate and acrylate are collectively referred to as (meth)acrylate), polypropylene glycol mono(meth)acrylate, phenoxyethyl Monofunctional (meth)acrylates such as (meth)acrylate; polyethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tri (
(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, hexanediol di(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, (meth)acrylate of polyhydric alcohol/alxylene oxide adduct ) Acrylate, (meth)acrylate of polyhydric phenol/alkylene oxide adduct, Special Publication Showa 4
No. 8-41708, Japanese Patent Publication No. 50-6034, Japanese Patent Publication No. 5
Urethane acrylate l described in each publication No. 1-37193, JP-A No. 4864183, and JP-A No. 49-4
Examples thereof include polyfunctional (meth)acrylates such as polyester acrylates and epoxy acrylates to which an epoxy resin and (meth)acrylic acid are added, which are described in Japanese Patent Publication No. 3191 and Japanese Patent Publication No. 52-30490.

The amount of these addition-polymerizable ethylenically unsaturated compounds used is preferably in the range of 5 to 70% by weight based on the solid content of the composition.

Examples of the diazo resin include diazo resins represented by salts of condensates of diazodiarylamine and active carbonyl compounds, and those that are photosensitive, water-insoluble, and soluble in organic solvents are preferred.

Particularly suitable diazo resins include 4-diazodiphenylamine, 4-diazo-3-methyldiphenylamine, 4-diazo-4'-methyldiphenylamine, 4-diazo-3'
-Methyldiphenylamine, 4-diazo-4'-methoxydiphenylamine, 4-diazo-3-methyl-4'-
Ethoxydiphenylamine, 4-diazo-3-methoxydiphenylamine, etc. and formaldehyde, paraformaldehyde, acetaldehyde, henzaldehyde, 4.
It is an organic acid salt or an inorganic acid salt of a condensation product with 4'-bis-methoxymethyldiphenyl ether, etc.

Examples of organic acids include methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, mesitylenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, propylnaphthalenesulfonic acid, ■-naphthol 5-sulfonic acid, Examples of the inorganic acid include hexafluoroline Examples include acids, tetrafluoroboric acid, thiocyanic acid, and the like.

Furthermore, a diazo resin whose main chain is a polyester group described in JP-A-54-30121; JP-A-61-2735;
A diazo resin obtained by reacting a polymer having a carboxylic acid anhydride residue described in Publication No. 38 with a diazo compound having a hydroxyl group; a diazo resin obtained by reacting a polyisocyanate compound with a diazo compound having a hydroxyl group, etc. Can be used.

The amount of these diazo resins used is preferably in the range of 0 to 40% by weight based on the solid content of the composition, and two or more types of diazo resins may be used in combination, if necessary.

Further, in the photosensitive composition of the present invention, other organic polymer binders can also be used together in an amount of 50% by weight or less based on the polyester resin. Examples of such organic polymer binders include acrylic resins, polyamide resins, polyurethane resins, epoxy resins, polyacetal resins, polystyrene resins, and novolac resins.

Furthermore, in order to improve performance, known additives such as thermal polymerization inhibitors, dyes, pigments, surfactants, plasticizers, stability improvers, etc. can be added.

Suitable dyes include, for example, basic oil-soluble dyes such as crystal violet, malachi green, Victoria blue methylene blue, ethyl violet, and rhodamine B. Commercially available products include, for example, "Victoria Pure Blue BOH," (manufactured by Hodogaya Chemical Industry Co., Ltd.)
and "Oil Blue #603J (manufactured by Orient Kagaku Kogyo Co., Ltd.). Examples of pigments include phthalocyanine blue, phthalocyanine green, dioxazine violet, and quinacridone red.

Examples of the surfactant include anionic surfactants,
Examples include nonionic surfactants and fluorine surfactants.

Examples of the plasticizer include diethyl phthalate, dibutyl phthalate, dioctyl phthalate, tributyl phosphate, trioctyl phosphate, tricresyl phosphate, tri(2-chloroethyl) phosphate, and tributyl citrate.

Further, known stability improvers such as phosphoric acid, phosphorous acid, oxalic acid, tartaric acid, malic acid, citric acid, dipicolinic acid, polyacrylic acid, benzenesulfonic acid, toluenesulfonic acid, etc. can also be used in combination.

The amount of these various additives added varies depending on the purpose, but is generally preferably in the range of 0 to 30% by weight of the solid content of the light-assembling composition for lithographic printing plates of the present invention.

Furthermore, a coating solvent can be added if necessary. Such coating solvents include, for example, halogenated solvents such as methylene chloride, chloroform, dichloroethane, trichloroethane, trichloroethylene, monochlorobenzene, dichlorobenzene, carbon tetrachloride, etc.; hexane, heptane,
Aliphatic or alicyclic or aromatic hydrocarbon solvents such as cyclohexane, benzene, toluene, xylene, etc.; Ether solvents such as tetrahydrofuran, dioxane, diethyl ether, ethyl propyl ether, dibutyl ether, engineered ethylene glycol dimethyl ether, etc.; glycols Ester solvents such as methyl ether acetate, glycol ethyl ether acetate, methyl acetate, ethyl acetate, butyl acetate, etc.; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-
Ketone solvents such as methyl-4-methoxy-2-pentanone; methanol, ethanol, propatool, butanol, tetrahydrofurfuryl alcohol, hensyl alcohol, diacetone alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether,
Alcohol solvents such as ethylene glycol monophenyl ether, cyclohexanol, etc.; acetonitrile,
Nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, nitrobenzene, etc.; dimethylsulfoxide, etc.; the above solvents can be used alone or in a mixture of two or more, and in some cases, A mixed solvent with water may also be used.

The photosensitive composition thus produced is applied to a support by a well-known coating method such as dip coating, curtain coating, roll coating, spray coating, polymer coating, spinner coating, air knife coating, doctor knife coating, etc. .

Supports include, for example, metal plates such as aluminum, zinc, copper, stainless steel, and iron; plastic films such as polyethylene terephthalate, polycarbonate, polyvinyl acetal, and polyethylene; paper and plastic coated with melt-coated synthetic resin or synthetic resin solution; Examples include composite materials in which a metal layer is provided on a film by techniques such as vacuum deposition and lamination; and various other materials used as supports for printing plates. In addition, in the case of a support with a metal surface, especially aluminum, grain treatment,
It is preferable that a surface treatment such as anodizing treatment or hydrophilic treatment is performed. The coating amount is usually about 0.5 to about 5 g/m<2 >in dry weight.

After coating, it is dried by a well-known method to obtain a photosensitive lithographic printing plate having a photosensitive layer provided on the support.

The photosensitive layer of this photosensitive lithographic printing plate is made of a polymer with excellent oxygen barrier properties, such as polyvinyl alcohol or acidic cellulose, in order to completely prevent the polymerization inhibition effect caused by oxygen in the air. A protective layer may also be provided. The photosensitive layer of this photosensitive lithographic printing plate is subjected to imagewise exposure using a negative image to harden and insolubilize the exposed areas of the photosensitive layer, and then developed with an aqueous alkaline developer to dissolve and remove the unexposed areas. A lithographic printing plate with a corresponding image formed thereon is obtained.

Suitable light sources used for exposure include, for example, carbon arc lamps, mercury lamps, metal halide lamps, xenon lamps,
Examples include chemical lamps and lasers.

Examples of the aqueous alkaline developer include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic ammonium phosphate, and sodium metasilicate. Examples include aqueous solutions containing alkaline agents such as sodium carbonate, aqueous ammonia, monoethanolamine, jetanolamine, triethanolamine, diisopropanolamine, monomethylamine, dimethylamine, and triethylamine. Furthermore, the solubility of the unexposed part of the photosensitive layer,
For the purpose of improving the permeability of the developer, anionic surfactants such as isopropylnaphthalene sodium sulfonate, dodecylbenzenesulfonic acid sodium, sodium salt of lauryl alcohol sulfate, and dialkylsulfosuccinate; benzyl alcohol, N-benzylethanolamine, Solvents such as phenoxyethanol, diacetone alcohol, methyl cellosolve, isopropyl alcohol, etc. can also be added.

The photosensitive composition of the present invention is useful as a photopolymerizable composition for lithographic printing plates, but is not necessarily limited to this use, and can be used for resin letterpress plates, screen printing plates, photoresists, color proofs, etc. It is also used for applications such as hologram forming materials.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

r Examples 1 to 6 (1) Synthesis of polyester resin having carboxyl groups in side chains Each mixture having the composition listed in Table 1 was placed in a stirring device together with a catalyst (dibutyltin dioxide, 0.4% by weight). , placed in a reactor equipped with a nitrogen gas inlet tube, a thermometer, and a distillation tube, and heated to 180°C while stirring under a nitrogen gas atmosphere.
The reaction was started by heating to . Thereafter, heating and stirring was continued for 3 hours, and the pressure inside the reactor was gradually reduced to 50 mmHg at the same temperature, and heating and stirring was continued for about 3 hours under the same reduced pressure. After distillate was distilled off, the reaction was continued. The pressure inside the vessel was returned to normal pressure with nitrogen gas, and an oligoester (A) having the acid value and hydroxyl value listed in Table 1 was obtained.

Next, 100 g of oligoester (A) was charged into a reactor equipped with a stirring device, a thermometer, and a cooling tube, and dissolved in dioxane to create a 60% by weight solution. Acid dianhydride was added with stirring.

Next, the temperature was raised to 110°C over 1 hour while stirring, the reaction was allowed to proceed for 8 hours at the same temperature, and the mixture was further diluted with dioxane to give 40°C.
It was made into a weight% solution. Then, a polyester resin solution having a carboxyl group in a side chain and having an acid value (in terms of solid content) and a weight average molecular weight as shown in Table 1 was obtained.

(2) Creation of photosensitive planographic printing plate The surface of a 0.30 m-thick aluminum plate was grained using a nylon brush and a 400 mesh water suspension of pumice stone, and then electrolyzed with 20% sulfuric acid. Anodized in liquid at a current density of 2A/di" to 2.1g/yl"
An oxide film was formed. After that, No. 3 sodium silicate
% aqueous solution for 60 cm for 1 minute, washed with water and dried to obtain a support.

The following photosensitive liquid was applied to this support using a roll coater, and 1
A photosensitive planographic printing plate was obtained by drying at 00°C for 3 minutes. At this time, the dry coating weight was 2.2 g/m''.

Photosensitive liquid (3) Preparation of planographic printing plate A halftone negative image film and a step wedge with a step height of 0.15 are brought into close contact with the photosensitive planographic printing plate obtained in (2), and the output is set at a position 1 m away from this. 1-metal halide lamp (Idol Fin 10 manufactured by Iwasaki Electric Co., Ltd.)
0OJ) for an exposure time that gave a photosensitivity of 5 steps. Thereafter, the plate was developed for 1 minute at 25° C. using the following developer to obtain a lithographic printing plate.

Developer *l) Urethane acrylate resin is “Millionate M
It is an adduct of R (manufactured by Nippon Polyurethane Industry ■, MDI polyisocyanate) and pentaerythritol triacrylate.

*2) Diazo resin is p-toluenesulfonate of a condensate of 4-diazodiphenylamine and paraformaldehyde.

*3) “Victoria Pure Blue BOHJ is a basic oil-soluble dye manufactured by Hodogaya Chemical Industry ■.

*4) "Perex NBL is a sodium alkylnaphthalene sulfonate-based anionic surfactant manufactured by Kao Atlas ■.

(4) Evaluation of the lithographic printing plate The lithographic printing plate prepared in (3) was installed on a Roland Fapolit printing machine, and the printing ink ``rCASP-G Beni'' (
(manufactured by Dainippon Ink & Chemicals), dampening water rHD78 (
Printing was performed using a 400-fold diluted solution (manufactured by Dainippon Ink & Chemicals Co., Ltd.).

The oil sensitivity is evaluated by the number of sheets printed until a printed matter with an appropriate ink density is obtained at the time of printing, and the smaller the number of sheets printed, the better the oil sensitivity is. (0710 sheets or less, 6210 sheets or less
~20 sheets, ×: 20 sheets or more) Rigidity resistance was evaluated by whether a printed matter faithful to the original image could be obtained without thickening halftone dots, skipping, etc. after printing 200,000 sheets.

The evaluation results are summarized in Table 1.

Examples 7 to 8 (1) Synthesis of unsaturated polyester resin having a carboxyl group in the side chain Each mixture having the composition listed in Table 2, catalyst (0.4% by weight of dibutyltin dioxide), and inhibitor Oligoester (B) having the acid value and hydroxyl value listed in Table 2, and
An unsaturated polyester resin solution having a carboxyl group in the side chain with the acid value (solid content equivalent value), unsaturated group concentration (solid content equivalent value), and weight average molecular weight listed in Table 2 (40% by weight)
) was obtained.

(2) Preparation of photosensitive planographic printing plates, preparation and evaluation of planographic printing plates The same treatments and tests as in (2) to (4) of Examples 1 to 6 were performed and the results are listed in Table 2.

In addition, the rigidity resistance is determined by the thickening of the halftone dots after printing 300,000 sheets.
Evaluation was made based on whether printed matter faithful to the original image could be obtained without skipping or the like.

Examples 19-23 In preparing the supports of Examples 1-6 (2), instead of anodizing in a 20% sulfuric acid electrolyte, 1.5 g of the oxide film was formed in a 20% phosphoric acid electrolyte. A support was obtained by carrying out the same treatment except that the anodization treatment was carried out so that the resultant layer became /re''.

The following photosensitive liquid was applied to this support using a roll coater, and 1
A photosensitive lithographic printing plate was obtained by drying for 3 minutes. At this time, the dry coating weight was 1.8 g/m''.

Photosensitive liquid polyester resin solution -7, -11, -14,15, -
Each photosensitive lithographic printing plate obtained using Example 1 to
The same treatments and tests as in Section 6 (3) and (4) were carried out, and the results are listed in Table 3.

〔Effect of the invention〕

The photosensitive composition of the present invention contains a polyester resin having a carboxyl group in the side chain, and when used in a photosensitive lithographic printing plate in particular, it can be developed with an aqueous alkaline developer and is obtainable. The relief image is wear-resistant,
A lithographic printing plate having good oil sensitivity and adhesion to a support and high printing durability can be obtained.

Claims (1)

[Claims] 1. A photosensitive composition comprising an alkali-soluble or swellable polyester resin having a carboxyl group in its side chain, an ethylenically unsaturated compound capable of addition polymerization, and a photopolymerization initiator. . 2. The photosensitive composition according to claim 1, wherein the polyester resin has a molecular weight of 1,000 to 150,000. 3. The photosensitive composition according to claim 1, wherein the polyester resin has a molecular weight of 7,000 to 60,000. 4. The photosensitive composition according to claim 1, 2 or 3, wherein the polyester resin has an acid value of 10 to 200. 5. The photosensitive composition according to claim 1, claim 2, claim 3, or claim 4, wherein the polyester resin has a carbon-carbon unsaturated bond. 6. The photosensitive composition according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the polyester resin has 0.1 to 5 equivalents of carbon-carbon unsaturated bonds per 1000 g of polyester resin. thing. 7. The photosensitive composition according to claim 1, claim 2, claim 3, claim 4, claim 5, or claim 6, which contains a diazo resin.