JPH02269344A - Damping waterless planographic printing plate material - Google Patents

Abstract

PURPOSE:To obtain the planographic printing plate which is excellent in plate wear, is good in dot reproducibility and does not require damping water by incorporating a binder having a specific constitutional unit into a photosensitive layer. CONSTITUTION:An addition polymerizable unsatd. compd., the binder which is a copolymer resin contg. the constitutional unit having a hydroxyl group and a photopolymn. initiator are incorporated into the photosensitive layer. The copolymer resin contg. the constitutional unit having >=30mol% hydroxyl group and carboxyl group is used preferably as the binder and the constitutional unit having the hydroxyl group or carboxyl group is exemplified by the constitutional unit expressed by formula I. In the formula I, R denotes a hydrogen atom, lower alkyl group, carboxyl group, etc.; X or Y denotes a direct bond, alkylene group, substd. alkylene group, etc. The photosensitive layer and a fluorine resin layer thereon are securely combined by the effect of the above- mentioned resin. A development latitude is widened in this way and the printing plate obtd. from this plate material is excellent in plate wear and small dot reproducibility.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lithographic printing plate material that does not require dampening water, and more specifically, the plate surface is less likely to be scratched and furthermore, it has good stiffness resistance when used for printing. The present invention also relates to a lithographic printing plate material that does not require dampening water and has improved shadow area and dot reproducibility.

[Background of the Invention] Conventionally, as a lithographic printing plate material that does not require dampening water (hereinafter referred to as a 1st plate material if necessary), one in which a photosensitive layer and an ink repellent layer are sequentially coated on a support is known. ing. By exposing and developing this plate material, a lithographic printing plate that does not require dampening water (hereinafter referred to as "printing plate" as necessary) can be obtained.

Since such plate materials originally use a fluororesin layer, this layer is difficult to scratch, but on the other hand, the adhesiveness between the photosensitive layer and the fluororesin layer is insufficient, and non-image areas may be damaged during development. The disadvantages are that the fluororesin layer is easily peeled off and the development latitude is narrow. Therefore, as a material with improved adhesiveness between such a photosensitive layer and a fluororesin layer, for example, WO33
No. 02175 discloses a plate material using an ink repellent layer made of a perfluoroalkyl compound having a metal atom and a functional group bonded to the metal atom. This plate material improves adhesion due to the presence of metal atoms and reduces the thickness of the ink repellent layer by 1
Printing plates made from this plate material are characterized by high resolution, as they can be made extremely thin, with a thickness of around 0.000 mm.

However, this printing plate has a problem in that it has insufficient stiffness resistance, not only does it cause streaks of staining on the entire plate surface, but also the fluororesin layer is not easily scratched.

JP-A No. 58-215411 discloses a plate material in which a photosensitive layer is a copolymer containing a specific fluorine-containing acrylic monomer and a monomer having a photosensitive group, and the photosensitive layer is made to have ink repellency. is disclosed.

However, the printing plate obtained from this plate material has the disadvantage of not having sufficient printing durability and poor dot reproducibility.

Furthermore, in an attempt to improve the printing durability and reproducibility of the printing plate obtained from this plate material, when the content of photosensitive groups in the plate material is increased, the ink repellency of the resulting printing plate decreases and the background There is also the problem of easy staining.

Therefore, the present inventors continued intensive research to improve the above-mentioned problems and drawbacks, and as a result, by using a specific resin as a binder in the photosensitive layer, the scratch resistance of the fluororesin layer was reduced. The present inventors have discovered that it is possible to maintain the ink repellent layer and at the same time to strengthen the adhesion between the ink repellent layer and the fluororesin layer used for the ink repellent layer, and have completed the present invention.

[Object of the Invention] Therefore, the object of the present invention is to obtain a printing plate that has a wider development latitude during development processing, has excellent printing durability, has excellent dot reproducibility, and does not cause scumming on the plate surface. The object of the present invention is to provide a lithographic printing plate material that does not require dampening water.

[Structure of the Invention] The object of the present invention is to provide a lithographic printing plate material that does not require dampening water and has a photosensitive layer and a fluororesin layer in this order on a support, in which the photosensitive layer contains an addition polymerizable unsaturated compound and a hydroxyl group. This was achieved by a lithographic printing plate material that does not require dampening water and is characterized by containing a binder, which is a copolymer resin containing structural units having the structure, and a photopolymerization initiator.

[Function] Since the plate material of the present invention uses a specific resin as a binder in the photosensitive layer, the photosensitive layer and the fluororesin layer are firmly bonded by the action of this resin.

Therefore, the development latitude is widened, and the printing plate obtained from this plate material has excellent stiffness resistance and excellent dot reproducibility.

[Specific structure of the invention] The present invention will be explained in more detail below.

The lithographic printing plate material of the present invention that does not require dampening water has a
A photosensitive layer and a fluororesin layer are provided in this order, and this photosensitive layer contains at least an addition polymerizable unsaturated compound, a binder that is a copolymer resin containing a structural unit having a hydroxyl group, and a photopolymerization initiator. In particular, this binder preferably contains 30 mol% or more of hydroxyl groups. More preferably, a copolymer resin containing a structural unit having 30 mol % or more of hydroxyl groups and a carboxyl group is used.

Examples of the structural unit having a hydroxyl group or carboxyl group include structural units represented by the following formulas.

X-C0OHY-OH [wherein R represents a hydrogen atom, a lower alkyl group, a carboxyl group, a hydroxyl group, a phenyl group, a substituted phenyl group, and X or Y represents a direct bond, an alkylene group, a substituted alkylene group, a phenylene group, a substituted Phenylene group, +-GOOR'--C
O40-82% (n represents an integer of 1 to 20) (Among these groups, R1 represents a substituent and R2 represents an alkylene group or a substituted alkylene group) In the binder used in the present invention , Specific examples of the above-mentioned structural units include: H3 C) 13 H Among these, the structural units (7), (8), and (9) are preferably used.

Monomers that can be copolymerized with this structural unit include styrene or its alkyl-substituted derivatives, alkyl acrylates, aryl acrylates, alkyl methacrylates, aryl methacrylates, or fatty acid vinyl esters. . Examples of preferred individual monomers among these are methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate,
Examples include butyl methacrylate, benzyl methacrylate, acrylonitrile, vinyl acetate, glycidyl (meth)acrylate, maleic anhydride, styrene, and the like.

It is also preferable that the binder of the present invention has an addition-polymerizable functional group.

Addition-polymerizable functional groups can be obtained, for example, by copolymerizing the above structural unit with allyl methacrylate, or by copolymerizing the above structural unit with allyl methacrylate, or
Publication No. 74, Japanese Unexamined Patent Publication No. 59-46643, Japanese Unexamined Patent Publication No. 59-46643
It can be introduced by reacting a compound having an addition-polymerizable unsaturated group such as pentaerythritol triacrylate or glycidyl methacrylate with a copolymer resin by the method described in Japanese Patent No. 71048 or the like.

The compound in the photosensitive layer may have a functional group that can react with a functional group in the fluororesin or crosslinking agent.

Further, the photosensitive layer may contain a photosensitive substance and, if necessary, other binders in addition to the above-mentioned binder.

Examples of the addition-polymerizable unsaturated compound, that is, the unsaturated compound used in the present invention, include the following.

Acrylic acids of alcohols (e.g. ethanol, propatool, hexanol, octatool, cyclohexanol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.) or methacrylic acid ester.

Amines (e.g. methylamine, ethylamine, butylamine, benzylamine, ethylenediamine, diethylenetriamine, hexamethylenediamine, xylylenediamine, dimethylamine, diethylamine, ethanolamine, jetanolamine, aniline, etc.) and glycidyl acrylate or glycidyl methacrylate reaction product with.

Carboxylic acids (e.g. acetic acid, propionic acid, benzoic acid,
acrylic acid, methacrylic acid, succinic acid, maleic acid, phthalic acid, tartaric acid, citric acid, etc.) and glycidyl acrylate or glycidyl methacrylate.

Amide derivatives (eg, acrylamide, methacrylamide, N-methylolacrylamide, methylenebisacrylamide, etc.).

Reactants of epoxy compounds and acrylic acid or methacrylic acid, etc.

The photopolymerizable composition containing the addition-polymerizable unsaturated compound used in the present invention contains a photopolymerization initiator, and the following can be used as the photopolymerization initiator.

Benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy α-phenylacetophenone, benzophenone, 2.4-
Benzophenone derivatives such as dichlorobenzophenone, methyl 0-benzoylbenzoate, 4.4°-bis(dimethylamino)benzophenone, 4,4′-bis(diethylamino)benzophenone, 2-chlorothioxanthone,
Thioxanthone conductors such as 2-isopropylthioxanthone, anthraquinone conductors such as 2-chloroanthraquinone and 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, αα
- Jetoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound, etc.

Further, in the present invention, the following photosensitive substances can be further used.

For example, it is a diazo resin represented by a condensate of an aromatic diazonium salt and formaldehyde.

Particularly preferred are salts of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as hexafluorophosphates, tetrafluoroborates,
Diazo resin inorganic salts, which are reaction products of perchlorate or periodate and the above condensate, and U.S. Patent No. 3,300
Examples include diazo resin organic salts which are reaction products of the above condensate and sulfonic acids, as described in No. 309 of the present invention.

In addition to the above, the photosensitive layer used in the present invention contains a dye (for example, Victoria Pure Blue 80) + (ffl manufactured by Tsuchiya Chemical Co., Ltd.) for making the image visible after exposure or development.
, triphenylmethane-based and diphenylmethane-based dyes such as Oil Blue '60:l (manufactured by Orient Kagaku Kogyo Co., Ltd.), alkyl ethers (e.g., ethyl cellulose, methyl cellulose, etc.) to improve coating properties, and fluorine-based surfactants. agents, nonionic surfactants (e.g., Pluronic L64 (manufactured by Asahi Denka Co., Ltd.), etc.), plasticizers for imparting flexibility to the coating film (e.g., polyethylene glycol,
phosphoric acid/tricresyl, acrylic acid or methacrylic acid polymers, etc.), stabilizers (for example, phosphoric acid, oxalic acid, tartaric acid, etc.).

In the present invention, a photosensitive composition comprising the above-mentioned components is applied to a support for plate material.

Next, the fluororesin layer used in the present invention specifically functions as an ink repellent layer, and the following fluororesins are used for this layer.

As the fluororesin, JP-A-52-74404 and JP-A-52-74404,
-74405, 58-83011, 58-887
Disclosed in various publications such as No. 50 and No. 58-90524,
Conventionally known or patent application No. 63-18246
6, No. 63-83011, No. 63-288129, etc., any of the fluororesins proposed by the present applicant can be used, including the following: can.

(1) The fluororesin molecule has the following structural unit, CF3-5-CF2- -CF-1CF3-0-5-
CF, -0-CF-0- (Fluorine content is 30% by weight or more, preferably 50% by weight or more) and (2) Fluorine is added directly or via a crosslinking agent to the molecule of this fluororesin. A fluororesin having a functional group that can react with each other and/or with a compound in a photosensitive layer to form a bond.

Examples of the above-mentioned functional groups include the following functional groups.

etc.

The above-mentioned fluororesin can be obtained by copolymerizing a fluorine-containing monomer and a monomer having the above-mentioned functional group.

Preferred examples of the monomer having a functional group include glycidyl methacrylate, methacrylic acid, maleic anhydride, 2-hydroxy methacrylate, and the like.

As the fluorine-containing monomer, a fluorine-containing acrylic monomer represented by the following general formula [11] is preferably used.

Numerical formula [II] R Rf-0-C-C-CHz [wherein, Rf is a substituted fluorine alkyl group or a substituted fluorine polyether group, and R is a hydrogen atom or an alkyl group.

] As the fluorine-containing polymer represented by the above-mentioned formula [II], those in which Rf has 5 to 10 carbon atoms are preferably used, and examples thereof include the following fluorine-containing polymers.

IH (2) It has a structural unit described in item (1) above in its molecule, and preferably has a functional group in its molecule that can form a bond with a compound in the photosensitive layer upon exposure to light. Fluorine resin.

Examples of the functional groups include addition-polymerizable unsaturated double bonds and epoxy groups.

An unsaturated double bond can be introduced into a fluororesin, for example, by the following method.

a. Copolymerizing a fluorine-containing acrylic monomer and allyl (meth)acrylate.

b. When the fluororesin has the functional groups described in item (1) above, a compound having both a functional group that can react with these functional groups and an unsaturated double bond, such as pentaerythritol triacrylate, 2-hydroxyethyl acrylate, acrylic acid, allylamine, tetrahydrophthalic anhydride, glycidyl (meth)acrylate, m-
Isopropenyl-α, α-dimethylbenzyl isocyanate, and 2-methacryloyloxyethyl isocyanate are reacted.

Preferably, a third mercury is copolymerized with the mercury described in item (1) above to improve film-forming properties and the like. Examples of the third polymer include styrene, methyl methacrylate (MMA), butyl acrylate, acrylonitrile, and ethyl acrylate. Specifically, the fluororesins listed below are preferably used.

■ Copolymer resin of perfluoroalkyl (meth)acrylate and allyl methacrylate ■ Copolymer resin of perfluoroalkyl (meth)acrylate and (meth)acrylic acid ■ Perfluoropolyether (meth)acrylate and (
A resin in which glycidyl (meth)acrylate is added to the product obtained by copolymerizing meth)acrylic acid and methyl (meth)acrylate ■Perfluoroalkyl (meth)
Copolymer resin of acrylate, 2-hydroxyethyl (meth)acrylate, alkyl (meth)acrylate, and acrylonitrile ■Perfluoroalkyl (meth)acrylate, 2-, droxyethyl (meth)acrylate, alkyl (meth)acrylate, and acrylonitrile A tree obtained by adding 2-methacroyloxyethyl isocyanate to a product obtained by copolymerization.The amount of the fluororesin used in the fluororesin layer in the present invention is generally 60 to 98% by weight, preferably It is 80-98% by weight.

The bonding between the fluororesin layer and the photosensitive layer according to the present invention is achieved by dissolving the fluororesin and an optionally added crosslinking agent in a suitable solvent, then coating it on the photosensitive layer, drying it, and then subjecting it to heat treatment. In this way, the fluororesin and the compound in the photosensitive layer are crosslinked via a crosslinking agent or directly.

In the present invention, the crosslinking agent used together with the fluororesin is a compound having two or more functional groups in its molecule that can react with the functional group described in item (1) above, and the crosslinking agent includes: Examples include the following:

Space below (1) Hexamethylene diisocyanate (lO) Little ylene-2,4-diisocyanate Pentaerythritol polyglycidyl ether Bisphenol A diglycidyl ether Pentaerythritol Pentaerythritol diacrylate Diethylene triamine Anhydride Hexahydrophthalic anhydride (11) Pyromellitic anhydride (12 ) meta-xylene diamine (13) 1. 3-Bis(α,α-dimethylisocyanate-methyl)benzene Preferably, polyisocyanate compounds such as hexamethylene diisocyanate, toluylene-2,4-diisocyanate, etc. are used in combination with a fluororesin having hydroxyl groups.

The amount of the crosslinking agent used in the fluororesin layer of the present invention is 0.3 to 30% by weight, preferably 1 to 10% by weight, which is extremely effective.

The support is preferably one that is flexible enough to be set in a normal lithographic printing machine and that can withstand the load applied during printing, such as metal plates such as aluminum, zinc, copper, and steel; Examples include metal plates plated or vapor-deposited with nickel, aluminum, iron, etc., paper, plastic films and glass plates, resin-coated paper, paper covered with metal foil such as aluminum, and the like.

Among these, aluminum plates are preferred.

In order to improve the adhesion between the support and the photosensitive layer, treatments for the support itself are not particularly limited, but include various surface roughening treatments.

The support may have a primer layer, and the primer layer may include, for example, polyester resin, vinyl chloride-vinyl acetate copolymer, arylate, vinyl chloride resin, polyamide resin, polyvinyl butyral resin, epoxy resin, arylate-based resin. Examples include copolymers, vinyl acetate copolymers, phenoxy resins, polyurethane resins, polycarbonate resins, polyacrylonitrile butadiene, polyvinyl acetate, and the like.

In addition, as the anchor agent constituting the primer layer,
For example, silane coupling agents, silicone primers, etc. can be used, and organic titanates and the like are also effective.

The thickness of each layer constituting the plate material of the present invention is as follows. That is, the support has a thickness of 50 to 400μ, preferably 10
0 to 300 μm 15 Photosensitive layer: 0.05 to 1 O μ −1 Preferably 0.5 to 5 μ m 1 Fluorine resin layer: 0.01 to 10 μ I
, preferably 0.1 to 1 μm.

In the present invention, a protective layer may be provided on the upper surface of the fluororesin layer, if necessary.

The plate material of the present invention that does not require dampening water can be produced, for example, as follows.

A composition solution to form a photosensitive layer is coated onto the support using a conventional coater such as a reverse roll coater, an air knife coater, a Meyer bar coater, or a rotary coater such as a Whaler, and then dried and heated if necessary. I'm curious.

If necessary, a brimer layer may be provided between the support and the photosensitive layer in the same manner as for the photosensitive layer.Next, a fluororesin and a crosslinking agent are coated on the photosensitive layer in the same manner.
A heat treatment is performed at a temperature of 00 to 120° C. for several minutes to fully cure and form a fluororesin layer. If necessary, a protective film can be provided on the fluororesin layer using a laminator.

Next, a method for manufacturing a printing plate that does not require dampening water using the plate material that does not require dampening water of the present invention will be explained.

A positive film, which is an original, is vacuum-adhered to the surface of a positive plate material and exposed. The light sources for this exposure include mercury lamps, carbon arc lamps, xenon lamps, and
Metal halide lamps, fluorescent lamps, etc. are used.

Next, the positive film is peeled off and developed using a developer. As the developer, a known developer for plate materials that does not require dampening water can be used. For example, aliphatic hydrocarbons (hexane, heptane, "Isoper E, H, G" (trade name of aliphatic hydrocarbons manufactured by Esso Chemical Co., Ltd.) or gasoline,
kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.)
, or halogenated hydrocarbons (trichlorethylene, etc.)
It is preferable to add the following polar solvent to the above.

Alcohols (methanol, ethanol, water, etc.), ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carpitol, diethylene glycol methyl ether, diethylene glycol dimethyl ether, tripropylene glycol methyl ether, ethyl carpitol, butyl carpitol, dioxane) etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, methyl cellosolve acetate, cellosolve acetate, carpitol acetate, etc.) In addition, dyes such as crystal violet and astrazonelet are added to the developer to create images at the same time as development. It is also possible to dye the area.

Development may be carried out by a known method, such as rubbing with a developing pad containing a developer as described above, or pouring a developer onto the printing plate and then rubbing with a developing brush.

By the above development, the fluororesin in the unexposed area is removed and the photosensitive layer, in some cases the brimer layer or the support, is exposed.
A printing plate is obtained in which the fluororesin layer remains in the exposed areas.

[Examples] Next, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 1) Present invention [Manufacture of aluminum plate a] An aluminum plate with a thickness of 0.2 mm was immersed in a 3% aqueous sodium hydroxide solution to degrease it, washed with water, and then diluted with 1% hydrochloric acid concentration.
and 3 at a temperature of 25°C in an aqueous solution with a boric acid concentration of 1%.
Electrolytic etching was performed for 5 minutes under the condition of "A/da", and after washing with water, etching was performed at 1.5 A at a temperature of 30°C in a 40% sulfuric acid aqueous solution.
/dam” for 2 minutes, washed with water,
% sodium metasilicate aqueous solution for 37 seconds at a temperature of 85°C, and further crushed for 25 seconds in water (pH 8.5) at a temperature of 90°C, washed with water, and dried to form an aluminum plate a.
I got it.

A photosensitive composition having the composition shown below was coated on the aluminum plate a thus obtained, and dried at 100°C for 2 minutes to a thickness of 2.
A photosensitive layer of μm was formed.

[Photosensitive composition] (1) The molar ratio of 2-hydroxyethyl methacrylate, styrene, acrylonitrile, and methyl methacrylate is 5
0.23.9.18 copolymer resin 50 parts (2-1)
4:1 adduct of glycidyl methacrylate and metaxylene diamine 25 parts <2-2) Trimethylolpropane triethoxy triacrylate 10 parts (2-3) Tetramethylolmethane tetraacrylate 5 parts (2-4) Trimethylolpropane triacrylate 25 parts of acrylate (3) 2.4-diethylthioxanthone 12.5
Part (4) p-dimethylaminobenzoic acid isoamyl ester 3 parts (5) Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd., dye) 0.2 parts (6) Methyl cellosolve 500 parts Then, the following was added to the surface of the photosensitive layer. The fluororesin composition-1 having the composition is applied and heated at 90°C for 10 minutes to crosslink the fluororesin and form a hardened fluororesin layer with a thickness of 1.0 μm, allowing for planographic printing without the need for dampening water. Got the edition.

[Fluororesin composition-1] (1) 50 parts of copolymer resin with a molar ratio of IH, LH, 2H, 2H-hebutadecafluorodecylacyl of 50.10.40 (2) Coronate E) I (Japan Polyurethane Co., Ltd., polyisocyanate) 3.5 parts (3) Dibutyltin dilaurate 0.05 part (4
) Freon - 113,500 parts (5) Methyl ethyl ketone 20 parts After a positive film was vacuum-adhered to the upper surface of the above plate material, it was exposed to light using a metal highland lamp as a light source.

The exposed plate material was then developed using the developer described below.

During development, only the unexposed portions of the fluororesin layer were easily removed by rubbing the surface of the plate material with a development bat.

A lithographic printing plate which did not require dampening water and which reproduced halftone dots of 2 to 98% and was excellent in both small dot reproducibility and shadow region reproducibility was obtained.

[Developer Composition] 5 parts of Isopar H, 85 parts of toluene, 10 parts of Tulfit (manufactured by Clarei Sobrene Chemical Co., Ltd.) Next, the above printing plate was attached to a Komori Sprint printing machine with the dampening water supply device removed, and WLP PRO
When printed from CESS W RED) I, 1
, 60,000 good prints were obtained.

2) In the photosensitive composition of Comparative Example 1, the copolymer resin of (1) was copolymerized with 〇-butyl methacrylate, methacrylic acid, and n-butyl acrylate in a molar ratio of 45.25.30. Mark 161 was made in the same manner as in Example 1 except that the material was changed to resin.
The first version was created.

The resulting printing plate had poor halftone dot reproducibility of 10 to 85%.

Example 2 1) In the photosensitive composition of Example 1, the copolymer resin (1) was mixed with 2-hydroxy methacrylate, styrene, acrylonitrile, butyl acrylate, and acrylic acid in a molar ratio of 5.
A printing plate was prepared in the same manner as in Example 1 except that the copolymer resin of 0.10.1014.26 was changed to a resin in which glycidyl methacrylate was added to the carboxyl group.

The resulting printing plate had good halftone dot reproducibility of 2 to 98%.

The number of printed matter obtained was 21,000, which was good.

2) In the photosensitive composition of Comparative Example 1, the copolymer resin of (1) was replaced with the carboxyl copolymer resin of styrene, acrylonitrile, butyl acrylate, and acrylic acid in a molar ratio of 49.10.4.37. A printing plate was prepared in the same manner as in Example 1 except that the resin was changed to one in which glycidyl methacrylate was added to 1/2 of the groups.

The obtained printing plate had poor halftone dot reproducibility of 5 to 90%.

The number of printed matter obtained was 0.8 million.

Example 3 1) In the photosensitive composition of Example 1, the molar ratio of copolymer resin (1) to 2-hydroxyethyl methacrylate, styrene, acrylonitrile, butyl acrylate, and acrylic acid was 40.1019.4. A printing plate was prepared in the same manner as in Example 1, except that the resin was changed to a resin in which glycidyl methacrylate was added to carboxyl group 172 of the copolymer resin of .37.

The resulting printing plate had good halftone dot reproducibility of 2 to 98%.

The obtained printed matter was 30,000 copies and was in good condition.

[Effects of the Invention] Since the present invention contains a binder having a specific structural unit in the photosensitive layer, the resulting lithographic printing plate that does not require dampening water has excellent printing durability and good halftone reproducibility. It was good. Furthermore, the difficulty of scratching the plate surface is further improved, and therefore, an excellent printing plate without scumming on the plate surface can be obtained.

Claims (1)

[Claims] In a lithographic printing plate material that does not require dampening water and has a photosensitive layer and a fluororesin layer in that order on a support, the photosensitive layer is an addition-polymerizable unsaturated compound and a copolymer resin containing a structural unit having a hydroxyl group. A lithographic printing plate material that does not require dampening water and is characterized by containing a photopolymerization initiator and a photopolymerization initiator.