JP2002178655A - Original plate for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original plate for a lithographic printing plate which show good abroad-the-machine development property, high sensitivity and high resistance to plate wear. SOLUTION: This original plate for the lithographic printing plate has a heat-sensitive layer containing at least either of a fine particle polymer or a microcapsule on a support composed of a graft polymer with a hydrophilic surface. In addition, the fine particle polymer is preferably a thermoplastic fine particle polymer or a fine particle polymer having a heat-reactive functional group, or the microcapsule is preferably a microcapsule encapsulating a chemical compound with the heat-reactive functional group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative type lithographic printing plate precursor. More specifically, it is a lithographic printing plate precursor that can perform plate making by scanning exposure based on digital signals, has high sensitivity and high printing durability, and can give a printed product without stain, without development. The present invention relates to a lithographic printing plate precursor that can be directly mounted on a printing press and printed.

[0002]

2. Description of the Related Art Numerous studies have been made on printing plates for computer-to-plate systems, which have been remarkably advanced in recent years. Among them, with the aim of further streamlining the process and solving the problem of waste liquid treatment, development-free lithographic printing plate precursors that can be mounted on a printing press and printed without being developed after exposure have been studied. Has been proposed.

[0003] One of the methods for eliminating the processing step is to mount an exposed printing plate precursor on a cylinder of a printing machine, and supply a dampening solution and ink while rotating the cylinder. There is a method called on-press development for removing a non-image portion. That is, after exposing the printing plate precursor,
It is a system that is mounted on a printing machine as it is and the processing is completed in the normal printing process. A lithographic printing plate precursor suitable for such on-press development has a photosensitive layer that is soluble in fountain solution and ink solvent, and is suitable for development on a printing machine placed in a bright room. It is required to have a light room handling property.

For example, Japanese Patent No. 2938397 discloses a lithographic printing plate precursor in which a photosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. ing. In this publication,
In the lithographic printing plate precursor, an image is formed by exposing the thermoplastic hydrophobic polymer fine particles by heat by exposing the plate to infrared rays, and then mounting the plate on a printing press cylinder, and using a fountain solution and / or ink. It is described that the above can be developed. However, in such a method of forming an image simply by heat coalescence, although good on-press developability is exhibited, printing durability is insufficient due to low image strength. Further, when the heat-sensitive layer is provided directly on the aluminum substrate, the generated heat is taken away by the aluminum substrate, so that coalescence due to heat does not occur on the interface between the substrate and the heat-sensitive layer, resulting in insufficient printing durability.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lithographic printing plate precursor which overcomes the above-mentioned disadvantages of the prior art. That is, an object of the present invention is to provide a lithographic printing plate precursor that has good on-press developability, high sensitivity, and high printing durability.

[0006]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and have found the present invention. That is, in order to increase sensitivity and increase printing life, it is most important to prevent the generated heat from being taken away by the aluminum substrate. The present inventors have found that a support having a hydrophilic surface has high hydrophilicity and an excellent heat insulating effect, which has led to the present invention. That is, the contents of the present invention are as follows.

(1) A lithographic printing plate precursor having a heat-sensitive layer containing at least one of a fine particle polymer and a microcapsule on a support having a hydrophilic surface made of a graft polymer. (2) The fine particle polymer is a thermoplastic fine particle polymer or a fine particle polymer having a thermoreactive functional group, or the microcapsule is a microcapsule containing a compound having a thermoreactive functional group. (1) A lithographic printing plate precursor.

[0008]

Embodiments of the present invention will be described below in detail.

The hydrophilic surface made of the graft polymer is a surface on which the hydrophilic graft polymer chain is present, and may be a surface where the hydrophilic graft polymer chain may be directly bonded to the surface. It may be one that is bonded to the stem polymer and bonded to the surface or coated or coated or crosslinked. Those in which the hydrophilic graft polymer chains are chemically bonded directly to the surface, or those in which the stem polymer having the hydrophilic graft polymer chains is chemically bonded, have a strong bond and can be used under severe printing conditions. It is preferable because the hydrophilic surface is not peeled off and the stainability can be maintained for a long time.

Method for Forming Surface Having Graft Polymer A surface comprising a graft polymer can be formed on a substrate by a well-known method. The method is described in, for example, The Japan Rubber Association, Vol. 65, 604, 1992,
You can refer to Shinji Sugii, surface modification and adhesion by macromonomer. Further, it can be prepared by a method called surface graft polymerization. In addition, it can also be prepared by introducing a hydrophilic graft chain into the crosslinked hydrophilic layer.

[Explanation of Surface Graft Polymerization] The surface prepared by the surface graft method refers to a surface obtained by grafting a monomer onto a polymer surface by a conventionally known method such as light, electron beam or heat. The monomer is a monomer having a positive charge such as ammonium or phosphonium or a monomer having a negative charge or an acidic group capable of dissociating into a negative charge such as a sulfonic acid group, a carboxyl group, a phosphate group, and a phosphonic acid group. And a hydroxyl group,
A monomer having a nonionic group such as an amide group, a sulfonamide group, an alkoxy group, and a cyano group may be used.
Graft polymerization is a method in which an active species is provided on a polymer compound chain, another monomer initiated by this is polymerized, and a graft (grafted) polymer is synthesized. When forming a surface, it is called surface graft polymerization. As the surface graft polymerization method for realizing the present invention, any of the known methods described in the literature can be used. For example, New Polymer Experimental Science 10, edited by The Society of Polymer Science, 1994, published by Kyoritsu Shuppan Co., Ltd., P135 describes a photograft polymerization method and a plasma irradiation graft polymerization method as surface graft polymerization methods. In addition, Handbook of Adsorption Techniques, NTS Corporation, supervised by Takeuchi, published on 1999.2, p203, p695, describes a radiation irradiation graft polymerization method such as γ-ray and electron beam.

Specific examples of the photograft polymerization method are described in JP-A-63-92658 and JP-A-10-29689.
5 and JP-A-11-119413 can be used. As a means for preparing a surface having a surface graft polymer, other than these, a trialkoxysilyl group at a terminal of a polymer compound chain,
A reactive functional group such as an isocyanate group, an amino group, a hydroxyl group, and a carboxyl group may be provided, and the reactive functional group may be formed by a coupling reaction between the reactive functional group and a functional group on the substrate surface. For the plasma irradiation graft polymerization method and the radiation irradiation graft polymerization method, see the above-mentioned literature and Y. Ikada et al, Macr.
omolecules vol. 19, page 1804 (1986). More specifically, the surface of a polymer such as PET is treated with plasma or an electron beam to generate radicals on the surface, and then the active surface is reacted with a monomer having a hydrophilic functional group, whereby the surface of the graft polymer is reacted. Layers can be obtained.

Photograft polymerization is described in JP-A-53-17407 (Kansai Paint) and JP-A-2000-212313 in addition to the above-mentioned documents.
As described in (Dainippon Ink), it can be prepared by applying a photopolymerizable composition to the surface of a base material, and then contacting the photopolymerizable composition with a hydrophilic radically polymerizable compound and irradiating light. A hydrophilic monomer is a monomer having a positive charge such as ammonium and phosphonium or an acidic group having a negative charge or capable of dissociating into a negative charge such as a sulfonic acid group, a carboxyl group, a phosphoric acid group, and a phosphonic acid group. In addition to the monomer, a hydrophilic monomer having a nonionic group such as a hydroxyl group, an amide group, a sulfonamide group, an alkoxy group, a cyano group, or the like may be used. Specific examples of the hydrophilic monomer particularly useful in the present invention include the following monomers. For example, (meth) acrylic acid or its alkali metal salt and amine salt, itaconic acid or its alkali metal salt and amine salt, allylamine or its hydrohalide salt, 3-vinylpropionic acid or its alkali metal salt and its amine salt , Vinylsulfonic acid or its alkali metal salt and amine salt, vinylstyrenesulfonic acid or its alkali metal salt and amine salt, 2-sulfoethylene (meth) acrylate, 3-sulfopropylene (meth) acrylate or its alkali metal salt and amine Salt, 2-acrylamido-2-methylpropanesulfonic acid or its alkali metal salt and amine salt, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, allylamine or its salt Carboxyl group, sulfonic acid group, phosphoric acid, amino group or salts thereof such as hydrogenate, carboxyl group, sulfonic acid group such as 2-trimethylaminoethyl (meth) acrylate or hydrohalide thereof , Phosphoric acid, an amino group or a salt thereof, and the like. Further, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, N-vinylpyrrolidone, N-vinylacetamide,
Allylamine or its hydrohalide, polyoxyethylene glycol mono (meth) acrylate and the like are also useful.

[Method of Introducing a Hydrophilic Graft Chain into the Crosslinked Hydrophilic Layer] The crosslinked hydrophilic layer into which the hydrophilic graft chain of the present invention has been introduced can be obtained by grafting a graft polymer by a generally known method for synthesizing a graft polymer. And then cross-linking it. Specifically, the synthesis of graft polymers is described in “Graft Polymerization and Its Applications” by Fumio Ide, published in 1977, The Society of Polymer Publishing, and “New Polymer Experimental Science 2: Synthesis and Reaction of Polymers” edited by the Society of Polymer Science , Kyoritsu Shuppan Co., Ltd. 1995. The synthesis of the graft polymer is basically as follows. Polymerizing the branch monomer from the trunk polymer,
2. 2. bonding a branch polymer to the trunk polymer; Copolymerization of a branch polymer with a trunk polymer (macromer method) can be divided into three methods. Of these three methods, the hydrophilic layer of the present invention can be prepared by using any of the three methods, but the macromer method 3 is excellent particularly from the viewpoint of production suitability and control of the film structure.

The synthesis of a graft polymer using a macromer is described in the above-mentioned "New Polymer Experiment 2, Synthesis and Reaction of Polymers", edited by the Society of Polymer Science, Kyoritsu Shuppan Co., Ltd., 1995. It is also described in detail in Yamashita et al., Macromonomer Chemistry and Industry, IPC, 1989. Specifically, acrylic acid, acrylamide, 2-acrylamide-2-
A hydrophilic macromer can be synthesized according to the method described in the literature using the hydrophilic monomer specifically described as the organic cross-linked hydrophilic layer such as methylpropanesulfonic acid and N-vinylacetamide. Particularly useful among the hydrophilic macromers used in the present invention are acrylic acid, macromers derived from carboxyl group-containing monomers such as methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylstyrenesulfonic acid. , And sulfonic acid-based macromers derived from monomers of salts thereof, N-vinylacetamide, amide-based macromers derived from N-vinylcarboxylic acid amide monomers such as N-vinylformamide, hydroxyethyl methacrylate,
Macromers derived from hydroxyl-containing monomers such as hydroxyethyl acrylate and glycerol monomethacrylate, and macromers derived from alkoxy- or ethylene oxide-containing monomers such as methoxyethyl acrylate, methoxypolyethylene glycol acrylate, and polyethylene glycol acrylate. Further, a monomer having a polyethylene glycol chain or a polypropylene glycol chain can also be usefully used as the macromer of the present invention.

The useful molecular weight of these macromers is
The range is from 400 to 100,000, the preferred range is from 1,000 to 50,000, and particularly the preferred range is from 1500 to 20,000. If the molecular weight is 400 or less, no effect can be obtained, and if it is 100,000 or more, the polymerizability with the copolymerizable monomer forming the main chain becomes poor. After synthesizing these hydrophilic macromers, one method of preparing a crosslinked hydrophilic layer into which the hydrophilic graft chains of the present invention have been introduced is to copolymerize the hydrophilic macromer with another monomer having a reactive functional group. , To synthesize a graft copolymer,
When the reactive functional group of the polymer and the crosslinking agent added in the layer are reacted to crosslink, or when the other monomer to be copolymerized with the macromer has a photocrosslinkable group, it may be crosslinked using light. . In the case of forming the crosslinked hydrophilic layer, after the component composition to be crosslinked is coated on a support described later, a photopolymerization reaction by whole-surface exposure such as ultraviolet irradiation or a polymerization reaction by heat is performed on the entire coating layer. Can be crosslinked. In the case where the surface of the crosslinked hydrophilic layer is rendered hydrophobic by heat or the like so that the surface itself functions as an image forming layer, the polymerization energy thereof does not cause a change in hydrophilicity / hydrophobicity of the image forming layer. For this purpose, the photopolymerization reaction is more preferable than the thermal polymerization reaction.

[Thermal Sensitive Layer] The thermosensitive layer of the present invention contains at least one of a fine particle polymer and a microcapsule. Specifically, it is preferable that the fine particle polymer is a thermoplastic fine particle polymer or a fine particle polymer having a thermoreactive functional group, or the microcapsule is a microcapsule containing a compound having a thermoreactive functional group. That is, it can contain at least one component selected from a thermoplastic fine particle polymer, a fine particle polymer having a thermoreactive functional group, and a microcapsule containing a compound having a thermoreactive functional group. Examples of the thermoplastic fine particle polymer include Research Disclosure No. 1 of January 1992. 33
303, JP-A-9-12387, 9-131
Nos. 850, 9-171249, 9-17
Suitable examples include thermoplastic fine particle polymers described in 1250 and EP931647. Specific examples include ethylene, styrene,
Examples include homopolymers or copolymers of monomers such as vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and the like, and mixtures thereof. Among them, polystyrene and polymethyl methacrylate are more preferable. However, particularly preferred are microcapsules containing a particulate polymer having a thermoreactive functional group and a compound having a thermoreactive functional group.

As the above-mentioned heat-reactive functional group, an ethylenically unsaturated group (for example, acryloyl group,
A methacryloyl group, a vinyl group, an allyl group, etc.), an isocyanate group which performs an addition reaction or a block thereof and a functional group having an active hydrogen atom which is a reaction partner thereof (eg, an amino group, a hydroxyl group, a carboxyl group, etc.); Epoxy group for addition reaction and its reaction partner amino group, carboxyl group or hydroxyl group, carboxyl group and hydroxyl group or amino group for condensation reaction, acid anhydride and amino group or hydroxyl group for ring opening addition reaction, etc. Can be mentioned. However, a functional group that performs any reaction may be used as long as a chemical bond is formed.

The fine particle polymer having a thermoreactive functional group used in the heat-sensitive layer of the present invention includes acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group,
Examples thereof include an amino group, a hydroxyl group, a carboxyl group, an isocyanate group, an acid anhydride and those having a group protecting them. The introduction of these functional groups into the polymer particles may be performed at the time of polymerization, or may be performed using a polymer reaction after polymerization.

When introduced during the polymerization, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having these functional groups. Specific examples of the monomer having such a functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate, glycidyl acrylate, and 2-
Block isocyanate with isocyanate ethyl methacrylate or its alcohol, block isocyanate with 2-isocyanate ethyl acrylate or its alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, Examples include, but are not limited to, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, bifunctional methacrylate, and the like. Examples of the monomer having no heat-reactive functional group copolymerizable with these monomers include, for example, styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, and vinyl acetate. The monomer is not limited to these as long as it has no monomer. As the polymer reaction used when the heat-reactive functional group is introduced after the polymerization, for example, WO96-34316
The polymer reaction described in Japanese Patent Application Laid-Open No. H10-260, can be mentioned.

Among the above-mentioned fine particle polymers having a thermoreactive functional group, those in which the fine particle polymers unite by heat are preferable, and those whose surface is hydrophilic and which disperses in water are particularly preferable. The contact angle (water droplets in the air) of a film produced by applying only the fine particle polymer and drying at a temperature lower than the coagulation temperature is lower than the contact angle of the film produced by drying at a temperature higher than the coagulation temperature ( (Water droplets in the air). In order to make the surface of the fine particle polymer hydrophilic as described above, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol, or a hydrophilic low-molecular compound may be adsorbed on the surface of the fine particle polymer. However, the present invention is not limited to this.

The solidification temperature of the fine particle polymer having a thermoreactive functional group is preferably 70 ° C. or higher, and more preferably 100 ° C. or higher in consideration of the stability over time. The average particle size of the fine particle polymer is preferably 0.01 to 20 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm. If the average particle size is too large, the resolution will be poor, and if it is too small, the stability over time will be poor.

The amount of the fine particle polymer having a reactive functional group to be added is preferably 50% by weight or more, more preferably 60% by weight or more based on the solid content of the thermosensitive layer.

The microcapsules used in the present invention are:
It contains a compound having a thermoreactive functional group. Compounds having this heat-reactive functional group include polymerizable unsaturated groups, hydroxyl groups, carboxyl groups or carboxylate groups or acid anhydrides, amino groups, epoxy groups,
And a compound having at least one functional group selected from an isocyanate group or a block thereof.

As the compound having a polymerizable unsaturated group,
At least one ethylenically unsaturated bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group;
And preferably two or more compounds. Such a compound group is widely known in the industrial field, and in the present invention, these can be used without particular limitation. These are, in chemical form, monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures or copolymers thereof.

Examples include unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids and fatty acids. Esters with aliphatic polyhydric alcohols and amides of unsaturated carboxylic acids with aliphatic polyhydric amines. Also,
An addition reaction product of an unsaturated carboxylic acid ester or unsaturated carboxylic acid amide having a nucleophilic substituent such as a hydroxyl group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or an epoxide; A dehydration-condensation reaction product with a functional carboxylic acid is also preferably used. Further, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group, and a monofunctional or polyfunctional alcohol,
Addition reactants with amines and thiols, and also substituted reactants with unsaturated carboxylic esters or amides having a leaving group such as a halogen group or a tosyloxy group, and monofunctional or polyfunctional alcohols, amines and thiols. It is suitable. Another preferred example is a compound in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid or chloromethylstyrene.

Specific examples of the polymerizable compound which is an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol include acrylates such as ethylene glycol diacrylate, triethylene glycol diacrylate,
3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane tris (acryloyloxypropyl) ether, trimethylolethane Triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate,
Pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate,
Examples thereof include sorbitol pentaacrylate, sorbitol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, and polyester acrylate oligomer.

Examples of the methacrylate include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol. Dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3- Methacryloyloxy-2 Hydroxypropoxy) phenyl]
Examples include dimethylmethane and bis- [p- (methacryloyloxyethoxy) phenyl] dimethylmethane.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate,
Examples thereof include 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, and sorbitol tetritaconate.

The crotonates include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Sorbitol tetradicrotonate and the like can be mentioned. Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Maleic esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate,
Sorbitol tetramalate and the like can be mentioned.

Examples of other esters include, for example, JP-B-46-27926, JP-B-51-47334,
Aliphatic alcohol esters described in JP-A-57-196231, JP-A-59-5240 and JP-A-59-196231
Examples thereof include those having an aromatic skeleton described in JP-A-5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613.

Specific examples of the amide monomer of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples thereof include diethylenetriaminetrisacrylamide, xylylenebisacrylamide, and xylylenebismethacrylamide. Examples of other preferred amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

A urethane-based addition-polymerizable compound produced by an addition reaction between an isocyanate and a hydroxyl group is also suitable.
JP-A-8-41708 discloses a polyisocyanate compound having two or more isocyanate groups in one molecule and an unsaturated monomer having a hydroxyl group represented by the following formula (I) added to one molecule. Urethane compounds containing at least two polymerizable unsaturated groups are exemplified.

Formula (I) CH ₂ C (R ¹ ) COOCH ₂ CH (R ² ) OH (where R ¹ and R ² represent H or CH ₃ )

Urethane acrylates described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, and JP-B-58-4.
9860, JP-B-56-17654, JP-B-62-
Urethane compounds having an ethylene oxide skeleton described in 39417 and JP-B-62-39418 can also be mentioned as suitable compounds.

Further, radical polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are preferable. It can be mentioned as.

Other preferred examples include polyester acrylates and epoxy resins described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. Examples thereof include polyfunctional acrylates and methacrylates such as epoxy acrylates obtained by reacting a resin with (meth) acrylic acid. In addition, JP-B-46-43946,
Specific unsaturated compounds described in JP-B-1-40337 and JP-A-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also preferable. In some cases, compounds containing a perfluoroalkyl group described in JP-A-61-22048 are also preferably used. Furthermore, The Adhesion Society of Japan, Vol. 20, No. 7, pp. 300-308 (198
Those introduced as photocurable monomers and oligomers in (4 years) can also be suitably used.

Suitable epoxy compounds include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols or hydrogenated products thereof. And polyglycidyl ether.

Suitable isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexane phenylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, or alcohol Alternatively, a compound blocked with an amine can be mentioned.

Suitable amine compounds include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.

Suitable compounds having a hydroxyl group include compounds having a terminal methylol group, polyhydric alcohols such as pentaerythritol, and bisphenols and polyphenols. Preferred compounds having a carboxyl group include pyromellitic acid, trimellitic acid, aromatic polycarboxylic acids such as phthalic acid,
Examples thereof include aliphatic polycarboxylic acids such as adipic acid. Preferred acid anhydrides include pyromellitic anhydride,
Benzophenone tetracarboxylic anhydride and the like.

A preferred copolymer of the ethylenically unsaturated compound is a copolymer of allyl methacrylate. For example, an allyl methacrylate / methacrylic acid copolymer, an allyl methacrylate / ethyl methacrylate copolymer, an allyl methacrylate / butyl methacrylate copolymer, and the like can be given.

As a method for microencapsulation, a known method can be applied. For example, as a method for producing microcapsules, US Pat.
U.S. Pat. No. 3,287,154, U.S. Pat. No. 3,287,154.
No. 38-19574, JP-B-42-446, JP-B-42-711, a method by precipitation of a polymer shown in U.S. Pat. Nos. 3,418,250 and 3,660,304, U.S. Pat. No. 3,796,669. U.S. Pat. No. 3,914,511, U.S. Pat. No. 4,087,376, U.S. Pat. No. 4,089,802, a method using an isocyanate polyol wall material as disclosed in U.S. Pat.
Method using resorcinol-based wall forming material, US Pat.
No. 025445, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, Japanese Patent Publication Nos. 36-9163 and 51-9079, an in situ method by monomer polymerization, and British Patent 930.
No. 422, U.S. Pat. No. 3,111,407, Spray drying method, British Patent Nos. 952807, 96707
No. 4, but not limited thereto.

The preferred microcapsule wall used in the present invention has three-dimensional crosslinking and has a property of swelling by a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. A compound having a thermoreactive functional group may be introduced into the microcapsule wall.

The average particle size of the above microcapsules is
0.01 to 20 μm is preferable, and 0.05 to
2.0 μm is more preferred, and 0.10 to 1.0 μm is particularly preferred. If the average particle size is too large, the resolution will be poor,
On the other hand, if it is too small, the stability over time will be poor. In such microcapsules, the capsules may or may not be united by heat. The point is that, among the microcapsule inclusions, those that have oozed out of the capsule surface or the outside of the microcapsules during application, or those that have penetrated into the microcapsule wall, may cause a chemical reaction by heat. It may react with the added hydrophilic resin or the added low molecular compound. The microcapsules may be reacted with each other by providing two or more types of microcapsules with functional groups that react with each other with different functional groups. Therefore, it is preferable from the viewpoint of image formation that the microcapsules are melted and united by heat, but it is not essential.

The amount of the microcapsules added to the thermosensitive layer is
In terms of solid content, preferably 50% by weight or more,
60% by weight or more is more preferable. Within this range, good sensitivity and printing durability can be obtained simultaneously with good on-press developability.

When the microcapsules are added to the heat-sensitive layer, a solvent in which the inclusions dissolve and the wall material swells can be added to the microcapsule dispersion medium. Such a solvent promotes the diffusion of the encapsulated compound having a thermoreactive functional group out of the microcapsules. Such a solvent depends on the microcapsule dispersion medium, the material, wall thickness, and inclusions of the microcapsule wall, but can be easily selected from many commercially available solvents. For example, in the case of water-dispersible microcapsules composed of crosslinked polyurea and polyurethane walls, alcohols,
Preferred are ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like.

Specific compounds include methanol, ethanol, tertiary butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, and γ-butyl lactone. , N, N-dimethylformamide, N, N-dimethylacetamide, etc., but are not limited thereto. In addition, these solvents
Two or more kinds may be used.

Solvents that do not dissolve in the microcapsule dispersion but can be dissolved by mixing the above solvents can also be used. The amount of addition is determined by the combination of materials. If the amount is less than the appropriate value, image formation becomes insufficient, and if the amount is too large, the stability of the dispersion is deteriorated. Normal,
The effective range is 5 to 95% by weight of the coating solution, the preferred range is 10 to 90% by weight, and the more preferred range is 15 to 85% by weight.

In the heat-sensitive layer of the present invention, since a fine particle polymer or a microcapsule having a heat-reactive group is used, a compound for initiating or promoting these reactions may be added as necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate radicals or cations by heat, and include, for example, lophine dimers, trihalomethyl compounds, peroxides, azo compounds, diazonium salts, and diphenyliodonium salts. Onium salts, acylphosphines, imidosulfonates and the like. These compounds can be added in the range of 1 to 20% by weight of the solid content of the heat-sensitive layer. Preferably it is in the range of 3 to 10% by weight. Within this range, a favorable reaction initiation or acceleration effect can be obtained without impairing the on-press developability.

The heat-sensitive layer of the present invention may contain a hydrophilic resin. The addition of the hydrophilic resin not only improves the on-press developability but also improves the film strength of the heat-sensitive layer itself. As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable.

Specific examples of the hydrophilic resin include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers,
Polyacrylic acids and their salts, polymethacrylic acids and their salts, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and Copolymers, hydroxybutyl methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight. Hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral , May include polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide, the N- methylol acrylamide homopolymers and copolymers, and the like.

The amount of the hydrophilic resin added to the heat-sensitive layer is preferably 5 to 40% by weight, and more preferably 10 to 30% by weight of the solid content of the photosensitive layer.
Is more preferred. Within this range, good on-press developability and film strength can be obtained.

In the heat-sensitive layer of the present invention, a light-to-heat conversion agent described in detail below may be added. The amount of the light-to-heat conversion agent added to the heat-sensitive layer is 30% by weight of the total solid of the heat-sensitive layer in the case of the organic light-to-heat conversion agent.
Can be added. Preferably 5 to 25% by weight
And particularly preferably 7 to 20% by weight. In the case of a metal fine particle type photothermal conversion agent, it is used in an amount of 10% by weight or more, preferably 20% by weight or more, particularly preferably 30% by weight or more of the total solids of the heat-sensitive layer. If it is less than 10% by weight, the sensitivity will be low.

Various compounds other than those described above may be added to the heat-sensitive layer of the present invention, if necessary. For example, a polyfunctional monomer can be added to the heat-sensitive layer matrix to further improve the printing durability. As the polyfunctional monomer, those exemplified as the monomer to be put in the microcapsule can be used. Particularly preferred monomers include trimethylolpropane triacrylate.

Further, after the image formation, the heat-sensitive layer of the present invention
In order to make it easy to distinguish between the image area and the non-image area, a dye having a large absorption in the visible light region can be used as a colorant for the image. Specifically, Oil Yellow # 10
1, oil yellow # 103, oil pink # 312,
Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black B
S, Oil Black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI)
42000), methylene blue (CI52015) and the like.
And dyes described in JP-A-62-293247. Further, pigments such as phthalocyanine pigments, azo pigments, and titanium oxide can also be suitably used. The amount of addition is 0.01 to 10% by weight based on the total solid content of the heat-sensitive layer coating solution.

In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the coating solution for the thermosensitive layer. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-
Butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol) , N
-Nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to 5% by weight based on the weight of the whole composition.
Also, if necessary, a higher fatty acid such as behenic acid or behenic acid amide or a derivative thereof is added to prevent polymerization inhibition by oxygen, and is unevenly distributed on the surface of the heat-sensitive layer in a drying process after coating. Is also good. The amount of the higher fatty acid or derivative thereof added is preferably about 0.1 to about 10% by weight of the solid content of the heat-sensitive layer.

Furthermore, a plasticizer can be added to the heat-sensitive layer of the present invention, if necessary, to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate,
Dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, and the like are used.

The heat-sensitive layer of the present invention is prepared by dissolving each of the above-mentioned necessary components in a solvent to prepare a coating solution, and is coated on the hydrophilic layer.
As the solvent used here, ethylene dichloride,
Cyclohexanone, methyl ethyl ketone, methanol,
Ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-
Methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyl lactone, toluene, water and the like,
It is not limited to this. These solvents are used alone or as a mixture. The solid concentration of the coating solution is preferably 1 to 50% by weight.

The coating amount (solid content) of the heat-sensitive layer on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.5 to 5.0 g / m ² . When the amount of coating is smaller than this range, the apparent sensitivity increases, but the film characteristics of the heat-sensitive layer that performs the function of image recording deteriorate. Various methods can be used as a method of applying. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating,
Examples include blade coating and roll coating.

The coating solution for the heat-sensitive layer according to the present invention may contain a surfactant for improving coating properties, for example, JP-A-62-1987.
A fluorinated surfactant as described in No. 170950 can be added. The preferred addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight of the total solids of the heat-sensitive layer.

Other Components Other Components Light-to-Heat Conversion Material When the lithographic printing plate precursor of the present invention is to be subjected to image formation by scanning exposure with a laser beam or the like, a hydrophilic surface composed of a graft polymer of the lithographic printing plate precursor is used. It is preferable that the layer or the heat-sensitive layer contains a light-to-heat conversion agent for converting light energy into heat energy. In the lithographic printing plate precursor of the present invention, as a photothermal conversion agent that may be contained,
Any substance that can convert light into heat by absorbing light such as ultraviolet light, visible light, infrared light, and white light can be used.For example, carbon black, carbon graphite, pigments, phthalocyanine pigments, metal powder, metal compound powder, and the like can be used. No.
Particularly preferred is a wavelength of 760 nm to 1200 nm.
Dyes, pigments, or metal powders that effectively absorb the infrared rays of
It is a metal compound powder. As the dye, commercially available dyes and known dyes described in literatures (for example, "Dye Handbook" edited by The Society of Synthetic Organic Chemistry, published in 1970) can be used.
Specifically, azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes,
Dyes such as a carbonium dye, a quinone imine dye, a methine dye, a cyanine dye, and a metal thiolate complex are exemplified.

Preferred dyes include, for example, those described in
Cyanine dyes described in JP-A-8-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, etc .;
No. 96, JP-A-58-181690, JP-A-58-1
No. 94595, etc., methine dyes described in
8-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996,
Naphthoquinone dyes described in JP-A-60-52940 and JP-A-60-63744;
Squarylium dyes described in No. 12792, etc.,
Cyanine dyes described in British Patent 434,875 and the like can be mentioned.

Further, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924 is also preferable. JP-A-57-142645 (U.S. Pat. No. 4,327,169) describes a trimethinethiapyrylium salt described in JP-A-58-181051, and JP-A-58-181051, and JP-A-58-181051.
Nos. 8-220143, 59-41363 and 59-
No. 84248, No. 59-84249, No. 59-146
Nos. 063 and 59-146061; cyanine dyes described in JP-A-59-216146; pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475; Fairness 5-135
Nos. 14 and 5-19702 are also preferably used.

Examples of other preferred dyes include those represented by formulas (I) and (I) described in US Pat. No. 4,756,993.
Mention may be made of near-infrared absorbing dyes described under I). Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. Examples of the pigment used in the present invention include commercially available pigments and color index (CI) handbook, “Latest Pigment Handbook” (edited by Japan Pigment Technical Association, 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986) and "Printing Ink Technology" published by CMC, 1984). The types of pigments include black pigment, yellow pigment, orange pigment, brown pigment, red pigment, purple pigment,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer-bound dyes. Specifically, insoluble azo pigments, azo lake pigments, condensation azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyeing lake pigments,
Azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.
Preferred among these pigments is carbon black.

[Overcoat Layer] In the lithographic printing plate precursor according to the present invention, a water-soluble overcoat layer can be provided on the heat-sensitive layer in order to prevent the surface of the heat-sensitive layer from being stained by a lipophilic substance. The water-soluble overcoat layer used in the present invention can be easily removed at the time of printing and contains a resin selected from water-soluble organic polymer compounds. As the water-soluble organic polymer compound used here, a film formed by coating and drying has a film-forming ability, specifically, polyvinyl acetate (having a hydrolysis rate of 65% or more), polyacrylic Acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal salt or amine Salt, polyacrylamide and its copolymer, polyhydroxyethyl acrylate, polyvinylpyrrolidone and its copolymer, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamide-2-methyl-1-methyl Propanesulfonic acid and its alka Metal salt or amine salt, poly-2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic, cellulose derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, Methyl dextrin) and modified products thereof, white dextrin, pullulan, enzymatically decomposed etherified dextrin and the like. Further, according to the purpose, two or more of these resins can be used in combination.

The above-mentioned water-soluble photothermal conversion agent may be added to the overcoat layer. Furthermore, in the case of aqueous solution application, a nonionic surfactant such as polyoxyethylene nonylphenyl ether and polyoxyethylene dodecyl ether can be added to the overcoat layer in order to ensure uniformity of application. . Dry coating amount of the overcoat layer, 0.1 to 2.0 g / m ² is preferred. Within this range, the surface of the heat-sensitive layer can be favorably prevented from being stained by a lipophilic substance such as a fingerprint stain without impairing the on-press developability. Support

The support used to form the hydrophilic surface comprising the graft polymer used in the present invention is not particularly limited, but is a dimensionally stable plate-like material.
For example, paper, plastic (eg, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, Cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which a metal as described above is laminated or vapor-deposited. As the support of the present invention,
A polyester film or an aluminum plate is preferred.
The support used to form the hydrophilic surface comprising the graft polymer preferably has a roughened support surface. Support surface (solid surface) used in the present invention
Will be described.

[Definition of surface irregularities] The center line average roughness Ra of the two-dimensional roughness parameter is 0.1 to 1 μm, and the maximum height Rt is
Is 1 to 10 μm, the ten-point average roughness Rz is 1 to 10 μm, the average interval Sm of unevenness is 5 to 80 μm, the average interval S between local peaks is 5 to 80 μm, the maximum height Rt is 1 to 10 μm, and the center line peak height. Rp is 1 to 10 μm, center line trough depth Rv is 1 to 1
0 μm. The two-dimensional roughness parameter is based on the following definition. Center line average roughness Ra: A value obtained by extracting a portion of the measured length L from the roughness curve in the direction of the center line and arithmetically averaging the absolute value of the deviation between the extracted center line and the roughness curve. Maximum height Rt: A value obtained by extracting a reference length from the roughness curve in the direction of the average line and measuring the distance between the peak line and the bottom line of the extracted portion in the direction of the longitudinal magnification of the roughness curve.

Ten-point average roughness: A reference length is extracted from the roughness curve in the direction of the average value, and measured from the average line of the extracted portion in the direction of the longitudinal magnification. The sum of the average of the absolute values of the altitudes (YP) and the average of the absolute values of the altitudes (Yv) of the valley bottoms from the lowest to the fifth, expressed in micrometers (μm). Average interval of unevenness Sm: A reference length is extracted from the roughness curve in the direction of the average line, and the sum of the average lines corresponding to one peak and one valley adjacent thereto is obtained in the extracted portion. Is the arithmetic mean of the intervals in millimeters (mm).

Average distance S between local peaks: A reference length is extracted from the roughness curve in the direction of the average line, and the length of the average line corresponding to the distance between adjacent local peaks in the extracted portion is determined. The arithmetic mean value of the distance between the peaks expressed in millimeters (mm). Maximum height Rt: value of the interval between two straight lines when the extracted portion is sandwiched between two straight lines parallel to the center line of the portion extracted by the reference length from the roughness curve. Centerline height RP: The value of the distance between the roughness curve and a straight line that passes through the highest peak and that is parallel to the centerline of the sampled part and that measures the measurement length L in the direction of the centerline. Center line valley depth RV: A value of a distance between a straight line passing through the deepest valley bottom and being parallel to the center line of the extracted portion, with a portion having a measured length L being extracted from the roughness curve in the center line direction.

[Plate Making and Printing] The lithographic printing plate precursor according to the present invention forms an image by heat. Specifically, direct image-like recording with a thermal recording head or the like, scanning exposure with an infrared laser, high illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, or the like is used.
Exposure with a solid-state high-output infrared laser such as a semiconductor laser or a YAG laser that emits infrared light of 00 nm is preferable. The lithographic printing plate precursor of the present invention, which has been image-exposed, can be mounted on a printing press without further processing, and can be printed in a usual procedure using ink and fountain solution. Further, as described in Japanese Patent No. 2938398, these lithographic printing plate precursors are mounted on a printing press cylinder, exposed by a laser mounted on the printing press, and then exposed to a fountain solution and / or Alternatively, it is also possible to carry out on-press development with ink. These lithographic printing plate precursors can also be used for printing after development using water or an appropriate aqueous solution as a developing solution.

[0073]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. [Synthesis of polymer microparticles (Synthesis of polymer microparticles (1) having a heat-reactive functional group) allyl methacrylate 7.5 g, butyl methacrylate 7.5 g, polyoxyethylene nonylphenol solution (concentration 9.84 × 10 ^-3 moll ^{- 1} ) Add 200 ml and replace the system with nitrogen gas while stirring at 250 rpm. After the solution was brought to 25 ° C., cerium (I
V) Ammonium salt aqueous solution (concentration 0.984 × 10 ⁻³ m)
all ^-1 ). At this time, an ammonium nitrate aqueous solution (concentration: 58.8 × 10 ⁻³ mol ⁻¹ ) was added,
Adjust the pH to 1.3-1.4. It was then stirred for 8 hours. The solid content of the liquid thus obtained was 9.5%, and the average particle diameter was 0.4 μm.

[Preparation of microcapsule (1)] As an oil phase component, 40 g of xylene diisocyanate, 10 g of trimethylolpropane diacrylate, a copolymer of allyl methacrylate and butyl methacrylate (molar ratio: 7 /
3) 10 g, pionin A41C (manufactured by Takemoto Yushi) 0.1
g was dissolved in 60 g of ethyl acetate. As an aqueous phase component, P
120 g of a 4% aqueous solution of VA205 (manufactured by Kuraray) was prepared. The oil phase component and the water phase component are separated using a homogenizer.
Emulsified at 10,000 rpm. Then, add 40 g of water,
The mixture was stirred at room temperature for 30 minutes and at 40 ° C. for 3 hours. The solid content concentration of the microcapsule solution thus obtained was 2
0%, and the average particle size was 0.5 μm.

[Preparation of Hydrophilic Supports 1 and 2] Preparation of a substrate having a surface made of a hydrophilic graft polymer A biaxially stretched polyethylene terephthalate film (A4100, manufactured by Toyobo Co., Ltd.) having a thickness of 188 μm was used. As the glow treatment, an oxygen glow treatment was performed under the following conditions using a lithographic magnetron sputtering apparatus (CFS-10-EP70 manufactured by Shibaura Eletech Corporation).

(Oxygen glow treatment conditions) Initial vacuum: 1.2 × 10 ⁻³ Pa, oxygen pressure: 0.9
Pa, RF glow: 1.5 KW, processing time: 60 sec

Next, the glow-processed film is
Aqueous sodium styrenesulfonate (10 Wt%)
It was immersed at 70 ° C. for 7 hours. 8 hours for the immersed membrane in water
By washing, sodium styrene sulfonate
Obtain a raft polymerized support (hydrophilic support 1)
Was. Similarly, sodium styrenesulfonate is converted to acrylic acid.
Acrylic acid is grafted in the same manner as above except that it has been changed
Obtained surface graft film (hydrophilic support 2)
Was. The following heat-sensitive layer is provided on the hydrophilic support 1 or 2 described above.
A coating solution was applied to form a heat-sensitive layer. After application, dry (O
100 ° C, 60sec in a bun, and the dry coating amount is 0.5g / m ^TwoWhen
I went to become.

(Coating solution of heat-sensitive layer (1)) Synthetic fine particle polymer (1) 5 g (in terms of solid content) 5 g of polyhydroxyethyl acrylate (weight average molecular weight 25,000) 0.5 g The following infrared absorbing dye (IR-11) ) 0.3g water 100g

(Coating solution of heat-sensitive layer (2)) Synthesized microcapsules (1) 5 g (in terms of solid content) 5 g of trimethylolpropane triacrylate 3 g of the following infrared absorbing dye (IR-11) 0.3 g water 60 g 1-methoxy- 40 g of 2-propanol

[0080]

Embedded image

[Examples 1 to 3] In the combinations shown in Table 1 below, lithographic printing plate precursors were prepared. Comparative Example 1 A printing plate precursor was prepared in the same manner as in Example 1 except that the following aluminum support was used for the hydrophilic surface as Comparative Example 1. Preparation of aluminum hydrophilic support Aluminum plate (material JISA1050, thickness 0.24
mm), using a known method, electrolytic graining in a nitric acid bath,
After anodizing in a sulfuric acid bath, treatment with an aqueous silicate solution was performed. Ra (center line surface roughness) of the support is 0.25μ
m, the amount of anodized film was 2.5 g / m ² , and the amount of silicon adhered was 10 mg / m ² .

Example 4 Example 1 was repeated except that a support having a crosslinked hydrophilic layer into which a hydrophilic graft chain was introduced (hydrophilic support 3) prepared by the following method was used as a hydrophilic support. A lithographic printing plate precursor was prepared in the same manner as described above. Method for producing a support having a crosslinked hydrophilic layer into which a hydrophilic graft chain has been introduced (hydrophilic support 3) (Synthesis of hydrophilic macromer, synthesis of amide macromonomer) 30 g of acrylamide and 3.8 g of 3-mercaptopropionic acid After dissolving in 70 g of ethanol
The temperature was raised to 0 ° C., and 300 mg of AIBN was added and reacted for 6 hours. After the reaction, the white precipitate was filtered and sufficiently washed with methanol to obtain 30.8 g of a terminal carboxylic acid prepolymer. 20 g of the obtained prepolymer was dissolved in 62 g of dimethyl sulfoxide, and 6.71 g of glycidyl methacrylate, 504 mg of N, N-dimethyldodecylamine (catalyst), and 62.4 mg of hydroquinone (polymerization inhibitor) were added.
The reaction was performed at 40 degrees for 7 hours. Add the reaction solution to acetone,
The polymer was precipitated and washed well to obtain 23.4 g of a terminal methacrylate acrylamide macromonomer (weight average molecular weight: 1400).

(Synthesis of Graft Polymer (1) Using Hydrophilic Macromer) Into a flask containing 5 g of distilled water, an aqueous solution obtained by dissolving 4 g of the above macromonomer, 6 g of methacrylic acid, and 100 mg of potassium persulfate in 17 g of distilled water was added with nitrogen. The solution was dropped at 65 ° C over 2 hours under an atmosphere. After completion of the dropwise addition, heating was continued for 6 hours. The reaction solution was added to acetone to precipitate the polymer, and the polymer was washed well.
9.5 g of acrylamide polymer was obtained. (Synthesis of graft polymer (1) having photocrosslinkable group) 9 g of the above graft polymer was dissolved in 200 g of DMAC, and 0.41 g of hydroquinone, 5 g of 2-methacryloyloxyethyl isocyanate and 0.1 g of dibutyltin dilaurate were dissolved.
5 g was added and reacted at 65 ° C. for 5 hours. After the reaction,
The reaction solution was cooled, the carboxyl group was neutralized with a 1N aqueous solution of sodium hydroxide, and the polymer was added to ethyl acetate to precipitate the polymer.

Preparation of Crosslinked Hydrophilic Layer The following composition was coated on an aluminum substrate so as to have a coating weight of 1.7 g / m ² , dried at 100 ° C. for 2 minutes, and exposed to UV to obtain hydrophilic graft chains. A support having a crosslinked hydrophilic layer into which was introduced (hydrophilic support 3) was produced.

Graft polymer having photocrosslinkable group (1) 1.0 g (as described above) Photopolymerization initiator A (structure below) 0.1 g Surfactant (1.5 wt% based on polymer) 12 0.7 g stabilized distilled water acetonitrile 6.4 g

[0086]

Embedded image

The on-press developable lithographic printing plate precursors obtained as in Examples 1 to 4 and Comparative Example 1 were exposed to a Creo Trendsetter 3244 VFS equipped with a water-cooled 40 W infrared semiconductor laser. After that, without processing, it was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg, and after supplying dampening water, supplying ink and further supplying paper, printing was performed. The exposure amount (sensitivity) required to form an image on each printing plate precursor, and the number of prints obtained by exposure and printing at this exposure amount are shown in Table 1 as printing durability.

[0088]

[Table 1]

From the above results, when a support having a hydrophilic surface comprising the graft polymer according to the present invention is used as compared with a conventional aluminum hydrophilic support, a lithographic printing plate having high sensitivity and excellent printing durability can be obtained. It turned out that the original was obtained.

[0090]

According to the present invention, an on-press development type lithographic printing plate precursor that can be mounted on a printing press as it is after exposure to light and overcomes the disadvantages of the prior art, and has good on-press developability. In addition, a lithographic printing plate precursor having high sensitivity and high printing durability can be obtained.

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁷ identification mark FI theme Court Bu (reference) G03F 7/038 G03F 7/038 7/11 503 7/11 503 (72) inventor Miki Takahashi, Shizuoka Prefecture Haibara-gun 4000 Kawajiri, Yoshida-machi Fuji Shashin Film Co., Ltd. F-term (reference) 2H025 AA00 AA01 AA12 AB03 AC08 AD01 BC32 BC42 BC51 CB14 CB16 DA10 DA18 DA20 DA36 FA03 FA10 2H096 AA00 BA05 BA06 BA20 CA05 CA20 EA04 2H114 AA04 DA22A DA52 DA56 DA73 DA78 EA01 EA03 FA16 GA34 GA36 GA38

Claims (2)

[Claims] 1. A lithographic printing plate precursor comprising a support having a hydrophilic surface made of a graft polymer and a heat-sensitive layer containing at least one of a fine particle polymer and microcapsules. 2. The method according to claim 1, wherein the fine particle polymer is a thermoplastic fine particle polymer or a fine particle polymer having a thermoreactive functional group, or the microcapsule is a microcapsule containing a compound having a thermoreactive functional group. The lithographic printing plate precursor according to claim 1.