JPH06236029A - Photosensitive resin composition and method for producing lithographic printing plate - Google Patents

Abstract

PURPOSE:To enable processing of planographic printing plates of both of a negative type and positive type by one kind of developer and one unit of automatic developing machine. CONSTITUTION:This photosensitive compsn. contains a polyester resin having a phenolic hydroxyl group in the side chains and a negative type photosensitive compd. on a base. This photosensitive planographic printing plate has a photosensitive layer consisting of this compsn. This process for production of the planographic printing plate consists in subjecting this planographic printing plate to image exposing, then to developing with the aq. alkaline developer contg. substantially no org. solvents. The negative type photosensitive planographic printing plate is developed by the aq. alkaline soln. contg. substantially no org. solvents, by which the planographic printing plate is obtd. without generating scum and sludge, etc., in the developer. Since the developer does not contain the org. solvent, there are no problems in sanitation. such as toxicity and smells at the time of work, and no problems in safety such as fires and gas explosion. In addition, the negative type planographic printing plate is produced by the processing similar to the processing for the conventional positive type photosensitive planographic printing plate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a photosensitive resin composition and a lithographic printing plate, and more particularly to a negative photosensitive resin composition and a method for producing the lithographic printing plate. More specifically, it relates to a photosensitive resin composition comprising a negative photosensitive compound and an organic polymer binder excellent in abrasion resistance and aqueous alkaline developability, and further, a photosensitive layer comprising the photosensitive resin composition. The present invention relates to a method for producing a lithographic printing plate by exposing a photosensitive lithographic printing plate having the above-mentioned image to an image and then developing it with an aqueous alkaline developer containing substantially no organic solvent.

[0002]

2. Description of the Related Art Photosensitive lithographic printing plates are roughly classified into a negative type in which an exposed portion becomes insoluble in a developing solution by light irradiation and a positive type in which an exposed portion becomes soluble in a developing solution by light irradiation.

Negative-working photosensitive lithographic printing plates are generally prepared by coating a photosensitive composition containing a negative-working photosensitive compound on a support such as an aluminum plate which has been subjected to surface roughening treatment. Through irradiation with actinic rays such as ultraviolet rays to polymerize or cross-link the light-irradiated portion to make it insoluble in the developing solution, and to elute the non-irradiated portion in the developing solution, repelling water respectively and oil-based ink To form a lithographic printing plate. This lithographic printing plate is printed by an offset printing machine by utilizing the lipophilicity of the image area and the hydrophilicity of the non-image area.

In this case, (1) a photosensitive diazonium compound, (2) a combination of a compound having an ethylenic illegal side and a photopolymerization initiator, and (3) a photosensitive compound are used as the negative photosensitive compound. There are combinations of the organic diazonium compound, the compound having an ethylenic illegal side, and the photopolymerization initiator.

As the photosensitive diazonium compound, 4-
Diazo resins typified by a condensation product of diazodiphenylamine and formaldehyde are commonly used.

The composition of the photosensitive layer of a photosensitive lithographic printing plate using a diazo resin is described in, for example, US Pat. No. 2,714,06.
No. 6, which is a diazo resin alone, for example, a mixture of an organic polymer binder and a diazo resin as described in JP-A No. 50-30604. However, the diazo resin alone has a weak abrasion resistance and cannot obtain sufficient printing durability,
Further, since the oil sensitivity is also insufficient, in recent years, most of photosensitive lithographic printing plates are composed of an organic polymer binder and a diazo resin.

As such a photosensitive layer, Japanese Patent Laid-Open No.
As described in Japanese Patent No. 30604, a so-called alkali development type in which an unexposed portion is removed (developed) by an aqueous alkaline developer and a so-called solvent development type in which an unexposed portion is removed by an organic solvent-based developer are known. However, from the viewpoint of occupational safety and health, the alkali developing type has attracted attention, which is mainly determined by the properties of the binder. As a method for imparting alkali developability to the binder, as described in JP-A-50-30634, a carboxylic acid-containing monomer is copolymerized or US Pat. No. 2,861,058. As described in the specification, there is a method of introducing a carboxylic acid into a polymer by reacting a hydroxyl group of polyvinyl alcohol with a cyclic anhydride such as phthalic anhydride. However, the abrasion resistance was poor, and only a lithographic printing plate having a low printing durability was obtained from the photosensitive lithographic printing plate containing such a binder in the photosensitive layer. On the other hand, polyvinyl acetal has a drawback that it forms a tough film and has abrasion resistance, but only a photosensitive lithographic printing plate of organic solvent developing type can be obtained.

There have been many attempts to use a photopolymerizable composition as a photosensitive image forming layer of a negative-working photosensitive lithographic printing plate, and a polymer as a binder as disclosed in JP-B-46-32714, A basic composition comprising a compound having an ethylenic unlawful side and a photopolymerization initiator, an unsaturated double bond was introduced into a polymer as a binder as disclosed in JP-B-49-34041 to improve curing efficiency. Composition, Japanese Patent Publication Nos. 48-38403 and 53-27605, and British Patent No. 1,
A composition using a novel photopolymerization initiator as disclosed in Japanese Patent No. 388,492 and the like is known, and some of them have been put to practical use. The sensitivity greatly depends on the surface temperature of the photosensitive lithographic printing plate during image exposure, and oxygen has a drawback that polymerization is strongly inhibited during image exposure.

On the other hand, an aqueous alkaline developer composition used when developing these negative type photosensitive lithographic printing plates after exposure is, for example, benzyl alcohol described in JP-A-51-77401. Developer composition comprising an anionic surfactant, an alkaline agent and water
JP-A-55-155355, a developer composition comprising an aqueous solution containing benzyl alcohol, an anionic surfactant, and a water-soluble sulfite, which is described in JP-A-3-44202.
The solubility in water described in No. 1 at room temperature is 1
A developer composition containing 0% by weight or less of an organic solvent, an alkaline agent, and water can be mentioned.

Each of these contains an organic solvent in the developer composition. However, the organic solvent generally has toxicity and odor, has a risk of fire, and has many drawbacks such as being subject to BOD regulation even in the waste liquid, and the cost becomes high.

As an alkaline developer composition containing substantially no such organic solvent, there is a developer composition described in JP-A-59-84241. However, these developer compositions are used when developing a positive-working photosensitive lithographic printing plate containing an o-naphthoquinonediazide compound as a photosensitive compound, and these developer compositions substantially contain no organic solvent. When the negative photosensitive lithographic printing plate described above is developed using a product, it cannot be developed without producing a residual film, and further, the unexposed portion is yellowed and proper developability cannot be obtained. There was a problem.

Therefore, the negative-type and positive-type photosensitive lithographic printing plates generally use their own developing solutions, and a large number of these two types of photosensitive lithographic printing plates are processed at the same time. In this case, two automatic developing machines and the like are required, and there is a problem in terms of economics such as equipment cost and equipment.

Further, when it is intended to commonly process both of these photosensitive lithographic printing plates by one automatic developing machine,
Depending on the type of photosensitive lithographic printing plate to be processed,
The developer had to be replaced, which was extremely wasteful in terms of work efficiency and economy.

In order to solve such a problem, a method of developing both photosensitive lithographic printing plates with the same developing solution has been conventionally proposed, but in the actual situation, good results have not been obtained yet. The reason may be as follows. That is, generally, the developer for a positive lithographic printing plate having a photosensitive layer composed of an o-quinonediazide compound and an alkali-soluble resin has a pH of 1 mainly containing silicate.
It is composed of two or more alkaline water, and when developing the unexposed area of a negative type lithographic printing plate composed of a water-insoluble diazo resin and an alkali-soluble resin using this developer, no development or residual development occurs. There is a problem that it is easy and stains tend to occur during printing. Further, when an acrylic resin having a high acid value or an alkali-soluble resin such as a styrene-maleic acid copolymer is used, it becomes possible to develop with a developer for a positive lithographic printing plate, but when a large number of printing plates are processed. There are problems that polymer sludge occurs and printing durability is extremely reduced. On the contrary, when developing the exposed part of the positive type lithographic printing plate with the developer for the negative type lithographic printing plate, similarly, the development cannot be performed well, and the residual film remains and stains may occur on printing. In the negative developing solution of the kind, the photosensitive layer of the positive type lithographic printing plate is easily dipped by the solvent contained in the negative developing solution, so that the development acceptability is narrowed, and the oil sensitivity and the printing durability are reduced. There was a problem such as a decrease.

The term "substantially free of organic solvent" means that the organic solvent is not contained to the extent of causing inconvenience in view of environmental hygiene, safety, workability and the like. In the invention, the proportion of the substance in the composition is 2% by weight or less, preferably 1% by weight or less.

[0016]

The problem to be solved by the present invention is to provide a photosensitive resin composition capable of obtaining a photosensitive layer having both excellent alkali developability and abrasion resistance. The problem of is to provide a method for producing a lithographic printing plate capable of developing a negative photosensitive lithographic printing plate with an aqueous alkaline developer containing substantially no organic solvent. An object of the present invention is to provide a method for producing a lithographic printing plate that does not have problems, safety problems such as fire and gas explosion, and problems such as pollution due to waste liquid.

Another problem to be solved by the present invention is that no sludge is generated even when a large number of sheets are developed using an aqueous alkaline developer containing substantially no organic solvent, and the printing durability is good. Another object of the present invention is to provide a method for producing a lithographic printing plate that gives a simple printing plate.

[0018]

In order to solve the above-mentioned problems, the present invention comprises (1) a polyester having a phenolic hydroxyl group or a modified product of the polyester and (2) a negative photosensitive compound. Provided is a photosensitive resin composition, and a photosensitive lithographic printing plate having a photosensitive layer formed of the composition, further after imagewise exposure of the photosensitive lithographic printing plate, an aqueous alkali containing substantially no organic solvent. Provided is a method for producing a lithographic printing plate, which comprises developing with a developing solution.

The negative photosensitive compound used in the method for producing the photosensitive resin composition and the lithographic printing plate of the present invention includes
A photosensitive compound selected from the following (A), (B) or (C) can be used.

(A) Photosensitive diazonium compound (B) Combination of compound having ethylenic illegal side and photopolymerization initiator (C) Combination of photosensitive diazonium compound, compound having ethylenic illegal side and photopolymerization initiator

Hereinafter, a polyester having a phenolic hydroxyl group or a modified product of the polyester and other components used in the composition of the present invention and a method for producing the same, and a method for producing a photosensitive composition used in the present invention and the present invention. The method for producing the lithographic printing plate will be described in detail.

The phenolic hydroxyl group-containing polyester or modified polyester used in the present invention is derived from, for example, (A) a polycarboxylic acid component containing a phenolic hydroxyl group-containing dicarboxylic acid or a derivative thereof and a polyhydric alcohol component. (B) A polyester having an alcoholic hydroxyl group obtained by reacting a polycarboxylic acid component containing a dicarboxylic acid having a phenolic hydroxyl group or a derivative thereof with a polyhydric alcohol component. A compound having two or more functional groups in the molecule having higher reactivity with the alcoholic hydroxyl group than with the phenolic hydroxyl group in the polyester [hereinafter referred to as a chain extender. ] A modified polyester having a phenolic hydroxyl group obtained by reacting

The polyester having a phenolic hydroxyl group or the modified polyester is, if necessary, another bond which does not react with the phenolic hydroxyl group in the polyester chain,
For example, it may have a urethane, amide, ureido, or ether bond.

Examples of the dicarboxylic acid having a phenolic hydroxyl group include dicarboxylic acids represented by the following general formulas (1) to (5).

[0025]

[Chemical 1]

[0026]

[Chemical 2]

[0027]

[Chemical 3]

[0028]

[Chemical 4]

[0029]

[Chemical 5]

(In the general formulas (1) to (5), R ₁ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or 1 to 4 carbon atoms.
Represents an alkoxyl group, a halogen atom or a nitro group,
R ₂ and R ₃ independently represent a hydrogen atom, a halogen atom, a nitro group or a cyano group, and X represents an alkylene group having 1 to 6 carbon atoms, an oxygen atom, a sulfur atom, a —CO— group, —SO.
Represents a group or a —SO ₂ — group, i represents an integer of 1 to 5, j represents an integer of (5-i), h and h ′ independently represent an integer of 1 to 4, and f Represents 0 or 1 and g represents (4
-H) represents an integer, and g'represents an integer of (4-h '). )

Examples of the dicarboxylic acid having a phenolic hydroxyl group and derivatives thereof include 4-hydroxybenzylidenemalonic acid, 3-hydroxybenzylidenemalonic acid, 3,4-dihydroxybenzylidenemalonic acid and 4-hydroxy-3. -Methoxybenzylidene malonic acid, 3-hydroxy-4-methoxybenzylidene malonic acid, 4-hydroxy-3-nitrobenzylidene malonic acid, 4-hydroxycinnamylidene malonic acid, 3-hydroxycinnamylidene malonic acid, 4-hydroxy- Three
-Methoxycinnamylidene malonic acid, 4-hydroxy-
Hydroxymalonic acids such as 3-nitrocinnamylidene malonic acid; 3-hydroxyphthalic acid, 4-hydroxyphthalic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid, hydroxyterephthalic acid, 3,6-dihydroxyphthalic acid, 2,5-dihydroxyisophthalic acid,
4,5-dihydroxyisophthalic acid, 2,3-dihydroxyterephthalic acid, 2,5-dihydroxyterephthalic acid, 2,4,6-trihydroxyisophthalic acid, 4,
5,6, -trihydroxyisophthalic acid, 4-hydroxy-5-nitroisophthalic acid, 4-hydroxy-5-chloroisophthalic acid, 3-hydroxy-6-methoxyphthalic acid, 2,4-dihydroxy-6-methylisophthalic acid Hydroxyphthalic acids such as acids; 3,3′-methylenebis (4-hydroxybenzoic acid), 4,6′-dihydroxy 3,3′-biphenyldicarboxylic acid, 6,6′-dihydroxy-5,5′-dimethoxy- Hydroxybiphenyldicarboxylic acids such as 3,3′-biphenyldicarboxylic acid and 4,5-dihydroxy-2,4′-oxydibenzoic acid; 2-hydroxy-p-benzenediacetic acid and 2,5-dihydroxy-p-benzenediacid Acetic acid, α, α′-dicyano-2,5-dihydroxy-p-benzenediacetic acid, α,
α'-dinitro-2,5-dihydroxy-p-benzenediacetic acid, α, α'-dichloro-2,5-dihydroxy-
Hydroxybenzenediacetic acid such as p-benzenediacetic acid and 5-hydroxy-m-phenylenedi (oxyacetic acid); dialkyl ester such as dimethyl ester and diethyl ester of the above dicarboxylic acid; di (ethylene glycol) ester of the above dicarboxylic acid And di (alkylene glycol) esters such as di (propylene glycol) ester.

In the production of polyester, the above-mentioned dicarboxylic acid having a phenolic hydroxyl group or its derivative can be used in combination with other polyvalent carboxylic acid or its derivative. Examples of such a compound include succinic acid and adipine. Acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, 1,4-cyclohexanedicarboxylic acid, maleic acid, fumaric acid, Examples thereof include polyvalent carboxylic acids such as itaconic acid, carboxynorbornane acetic acid, 5-sodium sulfoisophthalic acid, trimellitic acid, and hymic acid, or anhydrides or ester derivatives thereof.

On the other hand, various kinds of polyhydric alcohol components can be used without particular limitation, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, Aliphatic chain diols such as neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol; glycerol α-monoallyl ether, trimethylolpropane Monoallyl ether, pentaerythritol diallyl ether, N,
A diol having a carbon-carbon unsaturated bond such as N-diallyl tartaric acid diamide, 2-butene-1,4-diol, 2-butyne-1,4-diol; 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexane Dimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol F, propylene oxide adduct of bisphenol F Hydrogenated bisphenol A ethylene oxide adduct, hydrogenated bisphenol A propylene oxide adduct, tricyclodecane dimethanol ethylene oxide adduct, tricyclodecane dimethanol propylene oxide Adducts, 5-norbornene-2,3
Alicyclic and aromatic cyclic diols such as dimethanol, 5-norbornene-2,2-dimethanol, hydroquinone dihydroxyethyl ether, p-xylylene glycol; 2,2-bis (hydroxymethyl) propionic acid,
2,2-bis (hydroxyethyl) propionic acid, 2,
2-bis (3-hydroxypropyl) propionic acid,
A diol having a carboxyl group such as 2,2-bis (2-hydroxypropyl) propionic acid or 2,2-bis (hydroxymethyl) -n-butyric acid; a triol such as trimethylolpropane; a tetraol such as pentaerythritol. Can be mentioned.

The polyester synthesis is usually carried out by a method known in the art, for example, a book, "Course, Polymerization Reaction Theory 9, Polycondensation", Ogata, Kagaku Dojinsha, or JP-A-60-165646. U.S. Pat. No. 3,622,3
The polyester having a phenolic hydroxyl group in the side chain can be easily produced by the method described in JP-A-20-26.

Examples of the chain extender usable in the above (B) method include diaryl oxalate compounds, diaryl phthalate compounds, diaryl carbonate compounds,
Examples thereof include tetracarboxylic dianhydride.

As the diaryl oxalate compound,
Examples of the compound represented by the following general formula (6) and the diaryl phthalate compound include compounds represented by the following general formula (7), and examples of the diaryl carbonate compound include the compounds represented by the following general formula (8). be able to.

[0037]

[Chemical 6]

[0038]

[Chemical 7]

[0039]

[Chemical 8]

(In the general formulas (6) to (8), R ₁ and R ₂ each independently represent an aromatic hydrocarbon group which may have a substituent.)

Specific examples of R ₁ and R _{2 in} the above general formulas are as follows:

[0042]

[Chemical 9]

(In the formula, n represents an integer of 1 to 10, and X
Represents a halogen atom. ) Etc. can be mentioned.

Examples of the tetracarboxylic dianhydride include compounds represented by the following general formula (9).

[0045]

[Chemical 10]

(In the above general formula (9), R is at least 2
Represents a tetravalent organic group containing 4 carbon atoms. )

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′,
4,4'-diphenyltetracarboxylic dianhydride, 2,
3,6,7-naphthalenetetracarboxylic dianhydride,
1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4'-sulfonyldiphthalic dianhydride, 2,2
-Bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 4,4 '-[3,3'-(alkylphosphoryldiphenylene) -bis (Iminocarbonyl)] diphthalic dianhydride, an adduct of hydroquinone diacetate and trimellitic anhydride, an adduct of diacetyldiamine and trimellitic anhydride, and the like aromatic tetracarboxylic dianhydride; 5- (2 , 5-Dioxotetrahydrofuryl)-
3-Methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (Dainippon Ink and Chemicals, Inc., trade name "Epiclone B-4400"), butane-1,2,3,4-
Aliphatic tetracarboxylic dianhydrides such as tetracarboxylic dianhydride and cyclopentane tetracarboxylic dianhydride can be mentioned.

The modified polyester having a phenolic hydroxyl group can be synthesized by the reaction of the above-mentioned polyester with a chain extender, and can be easily produced, for example, by the method described in JP-A-60-221748.

At this time, the structure and the molecular weight of the (modified) polyester can be set to arbitrary values over a wide range by variously selecting the polycarboxylic acid component, the polyhydric alcohol component and the chain extender and varying the synthesis conditions. However, in order to be used for the intended purpose of the present invention, those having a weight average molecular weight of 1,000 to 100,000 are preferable, and further, in 1000 g of polyester or modified polyester, the general formula (1)
It is preferable to contain 0.5 mol or more of the structural unit represented by (5) to (5).

As the photosensitive diazonium compound, there is a diazo resin represented by a salt of a condensation product of a diazodiarylamine and an active carbonyl compound, and a photosensitive, water-insoluble and organic solvent-soluble compound is preferable.

Particularly preferred diazo resins are 4-diazodiphenylamine, 4-diazo-3-methyldiphenylamine, 4-diazo-4'-methyldiphenylamine and 4-diazo-4'-methyldiphenylamine.
Diazo-3'-methyldiphenylamine, 4-diazo-
4'-methoxydiphenylamine, 4-diazo-3-methyl-4'-ethoxydiphenylamine, 4-diazo-
3-methoxydiphenylamine and formaldehyde,
It is an organic acid salt or inorganic acid salt of a condensate with paraformaldehyde, acetaldehyde, benzaldehyde, 4,4′-bis-methoxymethyldiphenyl ether and the like.

Examples of the organic acid include methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, mesitylenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, propylnaphthalenesulfonic acid, 1-naphthol-5- Sulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,4-dihydroxybenzophenone, benzenephosphinic acid and the like can be mentioned. As the inorganic acid, hexafluorophosphoric acid, Examples thereof include tetrafluoroboric acid and thiocyanic acid.

Further, a diazo resin whose main chain is a polyester group described in JP-A-54-30121;
A diazo resin obtained by reacting a polymer having a carboxylic acid residue described in 1-273538 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 A diazo resin having a carboxyl group: A diazo resin having a phenolic hydroxyl group may 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 if necessary, two or more kinds of diazo resins may be used in combination.

As the compound having an ethylenic unlawful side, a monomer having a boiling point of 100 ° C. or higher under normal pressure and having at least 1, preferably 2 or more addition-polymerizable ethylenically unsaturated groups in one molecule, or It is an oligomer.
As such a monomer or oligomer, for example,
Polyethylene glycol mono (meth) acrylate [Hereinafter, methacrylate and acrylate are collectively referred to as (meth) acrylate. ], Monofunctional (meth) acrylates such as polypropylene glycol mono (meth) acrylate and phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, polypropylene 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 / alkylene oxide adduct, (meth) acrylate of polyhydric phenol / alkylene oxide adduct Relate, JP-B-48-41708, JP-B-50-603
4, urethane acrylates described in JP-B-51-37193, JP-A-48-64183.
No. 4, Japanese Patent Publication No. 49-43191, Japanese Patent Publication No. 52-3049
Polyfunctional (meth) acrylates such as polyester acrylates and epoxy acrylates obtained by adding (meth) acrylic acid to an epoxy resin described in JP-A No. 0 can be mentioned.

The amount of the compound having an ethylenic illegal side capable of addition polymerization is 5 with respect to the solid content of the composition.
The range of ˜70% by weight is preferred.

Examples of the photopolymerization initiator include α-carbonyl compounds described in US Pat. No. 2,366,661, acyloin ethers described in US Pat. No. 2,448,828, and US Pat. No. 27225.
.Alpha.-hydrocarbon substituted aromatic acyloin compounds described in US Pat. No. 12, polyquinone compounds described in US Pat. No. 3,046,127, US Pat. No. 3,549,367. A combination of triarylbiimidazole and p-aminophenyl ketone,
Trihalomethyl-s-triazine compounds described in US Pat. No. 4,239,850, US Pat.
Oxadiazole compounds described in JP-A-212970, acridine and phenazine compounds described in US Pat. No. 3,751,259, JP-B-5
Examples thereof include benzothiazole compounds described in JP-A No. 1-48516, and the amount thereof is preferably in the range of 0.5 to 20% by weight based on the solid content of the composition.

The photosensitive resin composition containing a photosensitive compound selected from the above (A), (B) or (C) and a polyester having a phenolic hydroxyl group or a modified product of the polyester may be any other organic polymer. A binder can also be used in combination. Examples of such organic polymer binders include acrylic resins, polyamide resins, polyurethane resins, phenoxy resins, epoxy resins, polyacetal resins, polystyrene resins, novolac resins, and the like.

Further, in order to improve the performance, known additives,
For example, a thermal polymerization inhibitor, dye, pigment, surfactant, plasticizer, stability improver and the like can be added.

Suitable dyes include, for example, crystal violet, maracay green, Victoria blue,
Examples include basic oil-soluble dyes such as methylene blue, ethyl violet, and rhodamine B. As a commercial product,
For example, "Victoria Pure Blue BOH" (manufactured by Hodogaya Chemical Co., Ltd.), "Oil Blue # 603" (manufactured by Orient Chemical Co., Ltd.) and the like can be mentioned. Examples of the pigment include phthalocyanine blue, phthalocyanine green, dioxazine violet, and quinacridone red.

Examples of the surface active agent include anionic surface active agents, nonionic surface active agents, fluorine surface active agents and the like.

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

Further known stability improvers include, for example:
Phosphoric acid, phosphorous acid, oxalic acid, tartaric acid, malic acid, citric acid, dipicolinic acid, polyacrylic acid, benzenesulfonic acid, toluenesulfonic acid and the like can also be used in combination.

The amount of these various additives added varies depending on the purpose, but generally, the solid content of the photosensitive composition is 0%.
The range of ˜30 wt% is preferred.

If necessary, a coating solvent can be added. Examples of such a coating solvent include halogen solvents such as methylene chloride, chloroform, dichloroethane, trichloroethane, trichloroethylene, monochlorobenzene, dichlorobenzene, carbon tetrachloride; hexane, heptane, cyclohexane, benzene, toluene, xylene, etc. An aliphatic or alicyclic or aromatic hydrocarbon solvent such as; an ether solvent such as tetrahydrofuran, dioxane, diethyl ether, ethylpropyl ether, dibutyl ether, ethylene glycol dimethyl ether; glycol methyl ether acetate, glycol ethyl ether acetate, Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, etc .; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-methyl Ketone-based solvent such as 4-methoxy-2-pentanone; methanol, ethanol, propanol, butanol, tetrahydrofurfuryl alcohol, benzyl alcohol, diacetone alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, Examples thereof include alcohol solvents such as ethylene glycol monophenyl ether and cyclohexanol; nitrogen-containing solvents such as acetonitrile, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and nitrobenzene; dimethyl sulfoxide and the like, and the above solvents may be used alone or It is also possible to use a mixture of two or more kinds, and depending on the case, a mixed solvent with water may also be used.

The photosensitive composition produced in this manner is applied to the support by a known coating method such as dip coating, curtain coating, roll coating, spray coating, whirler coating, spinner coating, air knife coating and doctor knife coating. Is applied.

As the support, for example, aluminum,
Metal plate of zinc, copper, stainless steel, iron, etc .; plastic film of polyethylene terephthalate, polycarbonate, polyvinyl acetal, polyethylene, etc .; paper on which synthetic resin is melt-coated or coated with synthetic resin solution, metal layer is vacuum-deposited and laminated on plastic film And other various materials used as a support for the printing plate. Further, in the case of a support having a surface of metal, especially aluminum,
Surface treatment such as graining treatment, anodic oxidation treatment, and hydrophilic treatment is preferably performed. The coating amount of the photosensitive composition is usually about 0.5 to about 5 g / m ² on a dry weight basis.

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

On the photosensitive layer of this photosensitive lithographic printing plate,
In order to completely prevent the polymerization inhibition effect by oxygen in the air, a protective layer made of a polymer having an excellent oxygen barrier property such as polyvinyl alcohol and acidic celluloses may be provided. The photosensitive layer of this photosensitive lithographic printing plate is imagewise exposed with a negative image to cure the exposed portion of the photosensitive layer to insolubilize it, and then it is developed with an aqueous alkaline developer containing substantially no organic solvent and unexposed. When the portion is dissolved and removed, a lithographic printing plate having a corresponding image formed on the support can be obtained.

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

Examples of the aqueous alkaline developer containing substantially no organic solvent according to the present invention include sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, trisodium phosphate, and the like. Dibasic sodium phosphate, tribasic potassium phosphate, dibasic potassium phosphate, tribasic ammonium phosphate, sodium metasilicate, sodium carbonate, potassium carbonate, annimore water, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine , Diisopropanolamine, monomethylamine, dimethylamine,
An aqueous solution containing an alkaline agent such as triethylamine may be mentioned.

The content of these alkaline agents in the developer composition is preferably in the range of 0.05 to 10% by weight,
A range of 1 to 7% by weight is particularly preferred.

If necessary, the developer composition
An anionic surfactant may be added. Anion interface
Examples of the active agent include lauryl alcohol sulfe.
Salt of octetate, octyl alcohol sulfate
Sodium salt of lauryl alcohol sulfate
Ammonium salt, secondary sodium alkyl sulfate, etc.
Higher alcohol sulfate ester salt having 8 to 22 carbon atoms
, Eg, cetyl alcohol phosphate ester, sodium
Phosphate salts of aliphatic alcohols, such as salt
For example, sodium salt of dodecylbenzene sulfonic acid,
Sodium salt of sopropylnaphthalene sulfonic acid, meta
Alkyl such as sodium salt of nitrobenzenesulfonic acid
Aryl sulfonates such as C₁₇H₃₃CON
(CH₃) CH ₂CH₂SO₃Alkylami such as Na
Sulfonates, such as sodium sulfo-amber
Acid dioctyl ester, sodium sulfosuccinate di
Sulfone of dibasic fatty acid ester such as xyl ester
Acid salts, such as lauroylmethylalanine, sodium
Salt, sodium salt of lauroyl sarcosine, cocoyl
N-acylamino such as sarcosine sodium salt
Acid salts and the like are included.

It is appropriate that the anionic surfactant is contained in an amount of 0 to 15% by weight or less based on the total weight of the developing solution at the time of use. If it is more than 15% by weight, for example, the elution (color loss) of the dye in the photocurable portion contained in the photocurable photosensitive solution becomes excessive, or the mechanical and chemical properties such as abrasion resistance of the photocured image are increased. There is an adverse effect such as deterioration of the physical strength.

The aqueous alkaline developer of the present invention may contain a very small amount of organic solvent.

As the organic solvent, those having a solubility in water of about 10% by weight or less are suitable, and those having a solubility of 5% by weight or less are preferable. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-
Propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p- Methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-
Methyl cyclohexanol, 4-methyl cyclohexanol, 3-methyl cyclohexanol, etc. can be mentioned.

The amount of the organic solvent used is 2% by weight or less, preferably 1% by weight or less, based on the total weight of the developing solution at the time of use.

If necessary, an antifoaming agent and a water softener
It is also possible to include additives such as Water softener
Is, for example, Na₂P₂O₇, Na_FiveP₃O₃, Na₃
P₃O ₉, Na₂O_FourP (NaO₃P) PO₃Na₂, Cargo
Polyphosphates such as sodium (sodium polymetaphosphate), eg
For example, ethylenediaminetetraacetic acid, its potassium salt,
Sodium salt of diethylenetriaminepentaacetic acid
Potassium salt, its sodium salt; triethylene tetra
Minhexaacetic acid, its potassium salt, its sodium salt;
Hydroxyethyl ethylenediamine triacetic acid, its potassium
Umium salt, its sodium salt; nitrilotriacetic acid, its mosquito salt
Lithium salt, its sodium salt; 1,2-diaminocyclo
Hexanetetraacetic acid, its potassium salt, its sodium
Salt; 1,3-diamino-2-propanoltetraacetic acid,
Aminoposide such as its potassium salt, its sodium salt, etc.
Licarboxylic acids can be mentioned. Hard water like this
Depending on the hardness of the hard water used and the amount used
The optimum amount changes, but if you show the general usage,
In the developer, the range of 0.01 to 5% by weight is preferable,
The range of 0.01 to 0.5% by weight is particularly preferable.

Further, the aqueous alkaline developer of the present invention contains
If necessary, a reducing inorganic salt may be contained.
The above-mentioned reducing inorganic salt has a reducing action,
Water-soluble inorganic salts are preferable, and salts of lower oxygen acids are particularly preferable. For example, sodium sulfite, potassium sulfite, ammonium sulfite, lithium sulfite, sodium bisulfite, sulfite salts such as potassium bisulfite, sodium phosphite, potassium phosphite, sodium hydrogen phosphite, potassium hydrogen phosphite, sodium dihydrogen phosphite, Examples include phosphites such as potassium dihydrogen phosphite. These are used alone or as a mixture. Among these, the alkali metal salt of sulfurous acid is preferable. The content of these reducing inorganic salts in the developer composition is preferably 0.001 to 30% by weight, and particularly preferably 0.01 to 10% by weight.

The aqueous alkaline developer of the present invention may contain an aqueous pyrazolone compound, an alkali-soluble mercapto compound, a 1,3-dihydroxy aromatic compound or a salt thereof, if necessary. These are used alone or as a mixture. The content in the developer composition is preferably 10% by weight or less, and the higher the content, the higher the ability to prevent stains in the non-image area. The mechanical strength deteriorates, and when applied to a lithographic printing plate, the printing durability is reduced.

The pH of the aqueous alkaline developer used is 11
Or more, preferably 12 or more.

Examples of such an aqueous alkaline developer containing substantially no organic solvent include, for example, JP-A-59-84.
The developing solutions described in JP-A No. 241 and JP-A-57-192952, which are used when developing the positive type lithographic printing plate after imagewise exposure, can be used.

If necessary, after development, washing with water, desensitization, or desensitization as it is, or treatment with an aqueous solution containing an acid, or desensitization after treatment with an aqueous solution containing an acid. You may give a process. Furthermore, in the developing step of this type of photosensitive lithographic printing plate, the alkaline solution is consumed depending on the processing amount to reduce the alkaline concentration, or the alkaline concentration is reduced by air due to long-term operation of the automatic developing machine. Although the processing capacity is reduced, in this case, JP-A-5
As described in JP-A-4-62004, the replenishing solution may be used to recover the processing capacity.

[0084]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(Synthesis Examples 1 to 8) Synthesis of (modified) polyester having phenolic hydroxyl group One-step method ... Each mixture having the composition shown in Table 1 was used together with a catalyst (0.4% by weight of dibutyltin oxide). A reactor equipped with a stirrer, a nitrogen gas introducing pipe, a thermometer and a distilling pipe was charged and heated to 190 ° C. with stirring under a nitrogen gas atmosphere to start the reaction. Then, the mixture was heated and stirred for 3 hours, and after the alcohol produced by the reaction stopped distilling, the pressure in the reactor was gradually reduced to 1 mmHg at the same temperature.
And Under the same reduced pressure, heating and stirring were further continued for about 5 hours, the distillate was distilled off, the pressure inside the reactor was returned to normal pressure with nitrogen gas, and the produced polyester resin was taken out.

Two-step method-1: The resin (100 g) synthesized by the above-mentioned one-step method was heated to 180 ° C. and stirred with stirring.
Charge the chain extender described in 1) and again set the pressure in the reactor to 1
After stirring at 180 ° C. for 2 hours, the by-produced phenol was distilled off, the pressure was returned to normal pressure, and the produced modified polyester resin was taken out.

Two-step method-2: The resin (100 g) synthesized by the above-mentioned one-step method was heated to 140 ° C., charged with the chain extender shown in Table 1 with stirring, and kept at normal pressure at 140 ° C. for 4 hours. The mixture was continuously stirred for reaction, and the resulting modified polyester resin was taken out. By the above synthesis method, (modified) polyesters 1 to 8 having a phenolic hydroxyl group having the weight average molecular weight shown in Table 1 were obtained.

[0088]

[Table 1]

(Examples 1 to 5) An aluminum plate having a thickness of 0.30 mm was degreased with an aqueous solution of sodium hydroxide, and this was electrolytically polished in a 2% hydrochloric acid bath to have a center line average roughness (R).
a) A 0.6 μm grain board was obtained. Then, anodize at a current density of 2 A / dm ² in a 20% sulfuric acid bath to give 2.7 g.
/ M ² oxide film was formed, and thereafter, a 3% aqueous solution of sodium silicate No. 3 was subjected to pore-sealing treatment at 60 ° C. for 1 minute, washed with water and dried to obtain a support.

The following photosensitive solution was coated on this support with a roll coater and dried at 100 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. At this time, the dry coating film weight was 2.0 g / m ² .

[Photosensitive Solution (Photosensitive Composition)] (Modified) Polyester 10.0 g Diazo Resin ^{* 1)} 1.2 g Malic Acid 0.1 g "Victoria Pure Blue BOH" ^{* 2)} 0.25 g Ethylene Glycol Monomethyl Ether 200 g

* 1) The diazo resin is p-toluenesulfonate of a condensate of 4-diazodiphenylamine and paraformaldehyde. * 2) Victoria Pure Blue BOH is a basic oil-soluble dye manufactured by Hodogaya Chemical Co., Ltd.

A film having a halftone negative image and a step of 0.15 step wedge were brought into close contact with the obtained photosensitive lithographic printing plate, and a light sensitivity of 4 was obtained by using a metal halide lamp having an output of 2 kW and provided at a position 1 m away from the film. The exposure was performed for an exposure time that gives a solid step. Then, it was developed with the following developer at 25 ° C. for 1 minute, washed with water, and then coated with a gum solution to obtain a lithographic printing plate.

[Developer] 1K potassium silicate aqueous solution (50%) 4.0 g sodium hydroxide 1.0 g sodium sulfite 0.5 g sodium alkylnaphthalene sulfonate 1.5 g water 93.0 g

The prepared lithographic printing plate was attached to a Roland Favorite printing machine, and printing ink "CAPS-G Red"
(Manufactured by Dainippon Ink and Chemicals, Inc.), dampening water "DH-7"
8 "(manufactured by Dainippon Ink and Chemicals, Inc.) was used for printing.

The printing durability was evaluated by whether or not a printed matter faithful to the original image could be obtained without generating dot thickening and plate skipping at the time of printing 50,000 sheets.

The evaluation results are summarized in Table 2. On the other hand, the above-mentioned photosensitive lithographic printing plate was treated with this developing solution to 4 m ² per 1 liter of developing solution, but no generation of dust or sludge was observed.

For comparison, when a commercially available diazo negative PS plate FNS-A (manufactured by Fuji Photo Film Co., Ltd.) was exposed and developed under the same conditions as in Example 1, it could not be developed.

[0099]

[Table 2]

(Examples 6 to 13) The following photosensitive solutions were coated on a support treated in the same manner as in Examples 1 to 5 with a roll coater and dried at 100 ° C for 3 minutes to obtain photosensitive lithographic printing plates. It was At this time, the dry coating film weight was 2.0 g / m ² .

[Photosensitive Solution (Photosensitive Composition)] (Modified) Polyester 10.0 g Urethane Acrylate ^{* 3)} 5.0 g Diazo Resin (Same as Example 1) 0.7 g 2- (4-Methoxynaphthyl) -4,6-bis (trichloromethyl) -S-triazine 0.5 g Oxalic acid 0.15 g "Victoria Pure Blue BOH" 0.2 g Ethylene glycol monomethyl ether 150 g Methyl ethyl ketone 50 g

* 3) Urethane acrylate is an adduct of "Millionate MR" (MDI type polyisocyanate manufactured by Nippon Polyurethane Industry Co., Ltd.) and pentaerythritol triacrylate.

A film of a halftone negative image and a step of 0.15 step wedge were brought into close contact with the obtained photosensitive lithographic printing plate, and a photosensitivity of 4 was obtained by using a metal halide lamp with an output of 2 kW provided at a position 1 m away from the film. The exposure was performed for an exposure time that gives a solid step. Then, it was developed with the developing solution at 25 ° C. for 1 minute, washed with water, and then coated with a gum solution to obtain a lithographic printing plate.

The prepared lithographic printing plate was attached to a Roland Favorite printing machine, and printing ink "CAPS-G Red" was used.
(Manufactured by Dainippon Ink and Chemicals, Inc.), dampening water "DH-7"
8 "(manufactured by Dainippon Ink and Chemicals, Inc.) was used for printing.

The printing durability was evaluated by whether or not a printed matter faithful to the original image could be obtained without generating dot thickening and plate skipping at the time of printing 100,000 sheets.

The evaluation results are summarized in Table 3.

On the other hand, the photosensitive lithographic printing plate was treated with this developing solution to 4 m ² per 1 liter of the developing solution, but no generation of dust or sludge was observed.

For comparison, instead of the (modified) polyester, "styrene / maleic anhydride copolymer [SMA-3
000, manufactured by Arco Chemical Co., Ltd.] and a resin having a phenolic hydroxyl group introduced into the side chain by an addition reaction of p-aminophenol "to prepare a photosensitive lithographic printing plate under the same conditions as in Example 6. Upon exposure and development, the developability was good, but the printing durability was poor, and plate skipping occurred at 20,000 sheets.

[0109]

[Table 3]

(Examples 14 to 16) In the preparation of the supports of Examples 1 to 5, instead of anodizing in 20% sulfuric acid electrolytic solution, an oxide film was formed in 20% phosphoric acid electrolytic solution. A support was obtained in the same manner except that the anodization treatment was performed so that the support had a concentration of 1.5 g / m ² .

The following photosensitive solution was applied to this support by a roll coater and dried at 100 ° C. for 3 minutes to obtain a photosensitive lithographic printing plate. At this time, the dry coating film weight was 1.8 g / m ² .

[Photosensitive Solution (Photosensitive Composition)] (Modified) Polyester 10.0 g Urethane Acrylate (Same as Used in Examples 6 to 13) 5.0 g 2- (4-Methoxynaphthyl) -4,6 -Bis (trichloromethyl) -S-triazine 0.6 g Copper phthalocyanine pigment 0.2 g Methyl ethyl ketone 50 g Ethylene glycol monomethyl ether 150 g

Each of the photosensitive lithographic printing plates obtained by using the (modified) polyester Nos. 1, 6, and 7 was subjected to the same treatments and tests as in Examples 1 to 5, and the results are shown in Table 4. .

[0114]

[Table 4]

[0115]

According to the photosensitive resin composition of the present invention, a negative photosensitive lithographic printing plate is developed with an aqueous alkaline developing solution containing substantially no organic solvent, thereby removing dusts in the developing solution. A lithographic printing plate can be obtained without causing sludge or the like. Further, since the developer does not contain an organic solvent, there are no health problems such as toxicity and odor during work, and safety problems such as fire and gas explosion. Further, a negative type lithographic printing plate can be manufactured by the same treatment as that of a conventional positive type photosensitive lithographic printing plate. Therefore, with one type of developer and one automatic processor,
Both negative-working and positive-working lithographic printing plates can be processed.

Claims (5)

[Claims] 1. A photosensitive resin composition comprising (1) a polyester having a phenolic hydroxyl group or a modified product of the polyester, and (2) a negative photosensitive compound. 2. The photosensitive resin composition according to claim 1, wherein the negative photosensitive compound is a compound having an ethylenically unsaturated group. 3. The photosensitive resin composition according to claim 1, wherein the negative photosensitive compound is a photosensitive diazonium compound. 4. A photosensitive lithographic printing plate having a photosensitive layer made of the photosensitive resin composition according to claim 1 on a support. 5. A method for producing a lithographic printing plate, which comprises subjecting the photosensitive lithographic printing plate according to claim 4 to image exposure and then developing it with an aqueous alkaline developer containing substantially no organic solvent.