JP2005329708A - Original plate of lithographic plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-press development type original plate of a lithographic plate which has an excellent on-press developability and is also excellent in fine line reproducibility, plate wear resistance and shelf stability or in a stain due to sticking of constituents removed in development to a form roller, and a lithographic printing method. <P>SOLUTION: The original plate of the lithographic plate has on a substrate an image recording layer which contains (A) a radical polymerization initiator, (B) a polymerizable compound and (C) a lipophilic binder polymer not containing substantially an acid radical, and can be removed by printing ink, dampening water or both of them. The polymerizable compound has in a molecule at least one structure selected from structures of (1) an ethylene oxide chain, (2) an alcohol hydroxyl group and (3) an isocyanuric acid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor that can be printed after exposure without going through a development processing step, and a lithographic printing method using the same.

In general, a lithographic printing plate has a surface composed of an oleophilic image portion and a hydrophilic non-image portion. In lithographic printing, dampening water and oil-based ink are alternately applied to the plate surface, and the hydrophilic non-image area is dampened with a dampening water receiving area (ink non-receiving area) by utilizing the property that water and oil repel each other. ), After the ink is received only in the oleophilic image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer to be an image portion is left, and other unnecessary image recording layers are made of an alkaline aqueous solution, an organic solvent, etc. A lithographic printing plate is obtained by making a plate by a method of forming a non-image portion by exposing the surface of the hydrophilic support by dissolving and removing with a developer.

  In the conventional plate making process of a lithographic printing plate precursor, after exposure, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary, but such additional wet processing is made unnecessary or Simplification is cited as one of the issues. In particular, in recent years, disposal of waste liquids discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and therefore, the demand for solving the above-mentioned problems has become stronger.

As one of the simple plate making methods corresponding to this, an image recording layer that can remove the image recording layer of the lithographic printing plate precursor in a normal printing process is used. A method called on-press development has been proposed in which the recording layer is removed to obtain a lithographic printing plate.
As a specific method of on-press development, for example, a method of using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in dampening water, an ink solvent, or an emulsion of dampening water and ink , Method of mechanically removing the image recording layer by contact with rollers or blankets of a printing press, cohesion of the image recording layer or adhesion between the image recording layer and the support by penetration of dampening water, ink solvent, etc. There is a method in which after the force is weakened, the image recording layer is mechanically removed by contact with rollers or a blanket.
In the present invention, unless otherwise specified, the “development process step” refers to using a device other than a printing press (usually an automatic developing machine) and bringing a liquid (usually an alkaline developer) into contact therewith. Refers to a step of removing an unnecessary image recording layer of the lithographic printing plate precursor and exposing the surface of the hydrophilic support, and “on-press development” refers to a liquid (usually printing ink and / or Or a dampening solution) to remove unnecessary image recording layers of the lithographic printing plate precursor and to expose a hydrophilic support surface.

  On the other hand, in recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread, and various new image output methods corresponding to such digitization technology have been put into practical use. It has come to be. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  As described above, in recent years, the simplification, drying, and no processing of plate making operations have become more desirable than ever in terms of consideration for the global environment and adaptation to digitalization. It is coming.

On the other hand, for example, Patent Document 1 describes a lithographic printing plate precursor in which an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. Yes. In this Patent Document 1, the above lithographic printing plate precursor is exposed by an infrared laser, and the hydrophobic thermoplastic polymer particles are coalesced by heat to form an image, which is then mounted on a cylinder of a printing press and moistened. It is described that it is possible to perform on-press development with water and / or ink.
However, it has been found that the above-described method for forming an image by merging the fine particles by simple thermal fusion exhibits good on-press developability but has low image strength and insufficient printing durability.

  For this reason, it has been proposed to improve printing durability using a polymerization reaction. For example, Patent Document 2 describes a lithographic printing plate precursor having an image recording layer (thermosensitive layer) containing microcapsules encapsulating a polymerizable compound on a hydrophilic support. Furthermore, Patent Document 3 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support.

Patent Document 4 has good on-press developability by including a compound having an ethylene oxide chain in an image forming layer containing a hydrophobizing precursor, a hydrophilic resin, and a photothermal conversion agent. It is described that it is possible to provide a lithographic printing plate precursor which is difficult to print and has high printing durability.
Japanese Patent No. 2938397 JP 2001-277740 A JP 2002-287334 A JP 2002-365789 A

However, in the above-described technology, compatibility between on-press developability and other characteristics, in particular, fine line reproducibility, printing durability, storage stability, and the problem of adhesion of the development removal component to the watering roller is still insufficient. .
Accordingly, an object of the present invention is to improve these problems, and has good on-machine developability, and fine line reproducibility, printing durability, storage stability, or adhesion contamination of the developer removal component to the watering roller is also included. An on-press development type lithographic printing plate precursor and a lithographic printing method are provided.

As a result of intensive studies, the present inventor has found that the above problems can be solved by using a polymerizable compound having a specific structure in combination with a binder polymer that substantially does not contain an acid group.
That is, the present invention is as follows.

  1. On the support, (A) a radical polymerization initiator, (B) a polymerizable compound, and (C) a lipophilic binder polymer substantially free of acid groups, printing ink, fountain solution, or both A lithographic printing plate precursor having an image-recording layer removable by the method, wherein the polymerizable compound is at least selected from (1) an ethylene oxide chain, (2) an alcoholic hydroxyl group, and (3) an isocyanuric acid structure in the molecule. A lithographic printing plate precursor having a single structure.

2. 2. The lithographic printing plate precursor as described in 1 above, wherein the image recording layer further contains (D) a photothermal conversion agent.
3. 3. The lithographic printing plate precursor as described in 1 or 2 above, wherein the support has an undercoat layer containing a crosslinkable group-containing compound.
4). 4. The lithographic printing plate precursor as described in 3 above, wherein the crosslinkable group-containing compound further has an adsorptive group.

5). The lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the image recording layer further comprises (E) a microcapsule.
6). 6. The lithographic printing plate precursor as described in any one of 1 to 5 above, which has a protective layer on the image recording layer.
7). 7. The lithographic printing plate precursor as described in 6 above, wherein the protective layer has a thickness of 0.1 to 5 μm.

  8). The lithographic printing plate precursor according to any one of 1 to 7 above is mounted on a printing machine and exposed imagewise with a laser, or after imagewise exposure with a laser, and mounted on a printing machine, A lithographic printing method in which printing ink and fountain solution are supplied to the lithographic printing plate precursor to remove a laser unexposed portion of the image recording layer and print.

  According to the present invention, after exposure, printing can be performed without going through a development processing step, it has good on-machine developability, and fine line reproducibility, printing durability, storage stability, or water for development removal components. An on-press development type lithographic printing plate precursor and a lithographic printing method with good adhesion contamination to the attaching roller can be provided.

(Image recording layer)
The image recording layer of the present invention has (A) a radical polymerization initiator, (B) a molecule having at least one structure selected from (1) an ethylene oxide chain, (2) an alcoholic hydroxyl group, and (3) an isocyanuric acid structure. A polymerizable compound having a specific structure (hereinafter also referred to as a polymerizable compound having a specific structure), and (C) an oleophilic binder polymer that does not substantially contain an acid group, and printing ink, dampening water, or both It can be removed.
Hereinafter, the components of the image recording layer will be described in detail.

<Polymerizable compound having a specific structure>
(1) Polymerizable compound having an ethylene oxide chain At least one radical polymerizable compound having an ethylene oxide chain (EO chain) in the molecule (hereinafter also referred to as an EO chain-containing polymerizable compound) that can be used in the present invention. It is an addition-polymerizable compound having an ethylenically unsaturated double bond and an EO chain. It is preferable to have two or more ethylenically unsaturated double bonds.

The EO chain-containing polymerizable compound of the present invention can be developed on-press immediately after the on-press development type lithographic printing plate precursor is produced, but when stored for a long time, the adhesion between the support and the image recording layer increases. This is particularly effective for improving the storage stability problem that the on-press development becomes impossible.
Although the detailed expression mechanism of storage stability improvement is unknown, the water permeability is increased by introducing an ethylene oxide chain having moderate hydrophilicity into the molecule, so that developability is improved and other hydrophilic properties are improved. Since the interaction between the ethylene oxide chain and the substrate support is extremely weak compared to the polar group, there is little change in adhesion during storage for high developability, and it is presumed that the effect of improving storage stability was obtained. . Further, unlike the case of simply adding an ethylene oxide group-containing compound, by introducing an ethylene oxide chain into the polymerizable compound, it is incorporated into a polymerization reaction for curing the film. As a result, the amount of unreacted compounds in the cured film is reduced, the image strength during printing is increased, and the sensitivity and printing durability are improved, thereby achieving both on-press developability and image formability. It has become possible.

Examples of the ethylenically unsaturated double bond in the EO chain-containing polymerizable compound of the present invention include vinyl group, 1-propenyl group, isopropenyl group, allyl group, 2-butenyl group, 1,3-butadienyl group, and acryloyl group. Methacryloyl group, crotonoyl group, methylene succinyl group, dialkylmaleimide group and the like. Of these, a vinyl group, an acryloyl group, and a methacryloyl group are preferable, and an acryloyl group and a methacryloyl group are more preferable.

The EO chain of the present invention has a structure in which ethylene oxide groups are linked repeatedly (—CH ₂ —CH ₂ —).
O-) represented by _n . n preferably represents an integer of 2 to 15, and more preferably an integer of 2 to 9.

  The ethylene oxide group content per molecule of the EO chain-containing polymerizable compound is 1 to 20 meq. / G, preferably 2 to 13 meq. / G is preferred. Within this range, good storage stability can be obtained even in storage at high temperatures without being accompanied by a decrease in image formability (a decrease in sensitivity and printing durability) due to deterioration in water resistance.

Examples of the compound of the radically polymerizable compound having an ethylene oxide chain in the molecule in the present invention include (1) a compound obtained by reacting an ethylene oxide (EO) group-containing alcohol with an unsaturated double bond-containing carboxylic acid, and other examples. (2) The compound etc. which made polyfunctional isocyanate react with the alcohol which has ethylene oxide group as described in Japanese Patent Publication No. 48-41708, and also added the monomer containing a hydroxyl group.
Specific examples of the radical polymerizable compound having an ethylenically unsaturated double bond and an EO chain are not particularly limited. For example, a compound having a structure represented by the following formula (i) in the molecule, and the following formula ( and a compound represented by ii).

^{_{CH 2 = C (R 1)}} -COO- (C 2 H 4 O) n -X- (i)
^{_{CH 2 = C (R 1)}} -COO- (C 2 H 4 O) n -Y (ii)

In formula (i), R ¹ represents a hydrogen atom or a methyl group, and n represents an integer of 2 to 15. X represents a linking group, for example, an alkylene group, an arylene group, an alkyleneoxy group, an aryleneoxy group, or a single bond. In formula (ii), R ¹ and n are as defined in formula (i), and Y represents an alkyl group, an aryl group, or an acyl group.
Specific examples of such compounds include, but are not limited to, the following compounds:

  As other EO chain-containing polymerizable compounds, 2-hydroxyethyl methacrylate is added to a polyisocyanate compound having two or more isocyanate groups per molecule described in JP-B-48-41708. Examples thereof include vinyl urethane compounds containing two or more polymerizable vinyl groups in the molecule.

(2) Polymerizable Compound Having Alcoholic Hydroxyl Group A radical polymerizable compound having an alcoholic hydroxyl group in a molecule which is a polymerizable compound having a specific structure of the present invention (hereinafter also referred to as a hydroxyl group-containing monomer) is a molecule. The content of the alcoholic hydroxyl group is preferably 1.9 to 20 meq. / G, more preferably 3 to 11 meq. / G.

  This hydroxyl group-containing monomer is particularly effective for improving the on-press developability, ink setting property and printing durability. The action of a new fact that a polymerizable compound having an alcoholic hydroxyl group, which is hydrophilic and generally considered disadvantageous for wearability and printing durability, has an unexpected effect of improving the wearability and printing durability. Although the mechanism is not clear, the alcoholic hydroxyl group of the polymerizable compound interacts with the components of the image recording layer through hydrogen bonding to increase the cohesive energy density of the image recording layer that has been exposed to polymerization and improve the image strength. I guess that is.

  The hydroxyl group-containing monomer of the present invention contains an ethylenically unsaturated double bond as a radical polymerizable group. Examples of the ethylenically unsaturated double bond include vinyl group, 1-propenyl group, isopropenyl group, allyl group, 2-butenyl group, 1,3-butadienyl group, acryloyl group, methacryloyl group, crotonoyl group, methylenesuccinyl group, And dialkylmaleimide groups. Of these, a vinyl group, an acryloyl group, and a methacryloyl group are preferable, and an acryloyl group and a methacryloyl group are more preferable.

  Such a hydroxyl group-containing monomer is a compound well known in the industrial field, and a known compound that matches the hydroxyl group content can be used without particular limitation. Among them, preferred are esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids, adducts of compounds having a plurality of epoxy groups and unsaturated carboxylic acids, and the like.

  Specific examples of such a hydroxyl group-containing monomer include, but are not limited to, the following.

  As esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids, pentaerythritol triacrylate, trimethylolpropane diacrylate, dipentaerythritol tetraacrylate, glycerin monoacrylate, glycerin diacrylate, sorbitol triacrylate, sorbitol tetraacrylate, Examples include pentaerythritol trimethacrylate, trimethylolpropane dimethacrylate, dipentaerythritol tetramethacrylate, glycerol monomethacrylate, glycerol dimethacrylate, sorbitol trimethacrylate, and sorbitol tetramethacrylate.

  Examples of the adduct of an epoxy compound and an unsaturated carboxylic acid include the following compounds.

(3) Polymerizable compound having an isocyanuric acid structure The polymerizable compound containing an isocyanuric acid structure, which is another polymerizable compound having a specific structure of the present invention, is a compound represented by the following structural formula.

In the formula, R _{1 to} R ₃ each independently represent a hydrogen atom, a polymerizable group, or —R ₄ —OH, and at least one of R _{1 to} R ₃ is a polymerizable group.
The polymerizable group is a group selected from a (meth) acryloyl group, a (meth) acryloyloxyalkyl group and an allyl group, and the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms. R ₄ represents an alkylene group, preferably an alkylene group having 1 to 6 carbon atoms.
In the present specification, acryloyl and methacryloyl are collectively referred to as (meth) acryloyl.

The polymerizable group of the polymerizable compound containing the isocyanuric acid structure is more preferably a compound containing two or more (meth) acryloyl groups from the viewpoint of polymerization efficiency.
In addition, a compound having a hydroxyl group is preferable because it exhibits high printing durability particularly when combined with an image recording layer containing microcapsules. This is thought to be because the hydroxyl group interacts with the microcapsule wall and the dispersing agent to improve the strength of the image area.

Specific examples of the polymerizable compound having an isocyanuric acid structure of the present invention include tris [(meth) acryloyloxymethyl] isocyanurate, tris [(meth) acryloyloxyethyl] isocyanurate, tris [(meth) acryloyloxypropyl]. Isocyanurate, triallyl isocyanurate, bis [(meth) acryloyloxyethyl] hydroxyethyl isocyanurate, bis [(meth) acryloyloxymethyl] isocyanurate, allylhydroxylethyl isocyanurate, (meth) acryloyloxyethyl isocyanurate, etc. Can be mentioned.
These may be used alone or in combination of two or more.

The above-mentioned polymerizable compound containing an isocyanuric acid structure is particularly improved in the problem that the substance removed in the on-press development deposits as a residue on the wet roller and interferes with the supply of dampening water. It is effective for.
On-machine development is performed by removing the unexposed image recording layer by the force of dissolving the image recording layer of the fountain solution and the ink and the physical force of the water roller and the ink roller for supplying the fountain solution and the ink. However, the polymerizable compound containing an isocyanuric acid structure reduces the on-press developability of the image recording layer by the dampening solution and the dampening roller, and improves the development by the ink and the ink roller. It is presumed that the on-machine development removing substance is unlikely to deposit as a residue on the water roller, because it is specifically larger than the soluble polymerizable compound.

  The content of the polymerizable compound having the specific structure of the present invention in the image recording layer is preferably 5 to 80% by mass, more preferably 25 to 75% by mass based on the solid content of the image recording layer.

In the present invention, two or more polymerizable compounds having the above specific structure can be used in combination. Moreover, polymerizable compounds other than those having the above specific structure can be used in combination. Examples of the polymerizable compound other than those having a specific structure include polymerizable compounds known in the industrial field having at least one, preferably two or more ethylenically unsaturated bonds.
When using a polymerizable compound other than those having the above specific structure, the ratio of the polymerizable compound having the specific structure to the total polymerizable compound is preferably 30% by mass or more, and preferably 50% by mass or more. More preferred. Within this range, the effect of the polymerizable compound having the specific structure is sufficiently exhibited.

<(A) Radical polymerization initiator>
The radical polymerization initiator used in the present invention (hereinafter also simply referred to as a polymerization initiator or a radical generator) generates radicals by light or thermal energy, and initiates polymerization of a compound having a polymerizable unsaturated group. It is a compound that promotes. As such a radical generator, a known polymerization initiator or a compound having a bond having a small bond dissociation energy can be appropriately selected and used.

  Examples of the compound that generates radicals include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oxime ester compounds. And onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. Examples thereof include compounds described in Hutt, “Journal of Heterocyclic Chemistry” 1 (No. 3), (1970). Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

  More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring, and oxadiazole derivatives in which the oxadiazole ring is bonded. Specifically, for example, 2,4,6-tris (monochloromethyl) -s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [1- (P-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- ( -Methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p- Tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenylthio-4,6-bis ( Trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris ( Tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) Etc. -s- triazine and the following compounds.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenyl) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p- Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, and JP-A-5-83588. Various titanocene compounds described in each publication, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopenta Dienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di-cyclopentadi Enyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1 , Di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl Di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6 -Pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453, JP-A-1-152109, and the like.

Examples of the hexaarylbiimidazole compound include the specification of JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And, specifically, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromophenyl) )) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (
o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (m-methoxyphenyl) ) Bididazole, 2,2′-bis (o, o′-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-nitrophenyl) -4,4 ′ , 5,
5′-tetraphenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′
, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, and the like.

  Examples of the organoboron compound include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A 2000-. No. 131837, JP 2002-107916 A, JP 2764769 A, JP 2002-116539 A, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, etc. Organoboron salts described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes, No. 175554, JP-A-6-17555 Organoboron iodonium complex described in JP-A-9-188, organoboron phosphonium complex described in JP-A-9-188710, JP-A-6-34811, JP-A-7-128785, JP-A-7-140589, Examples thereof include organoboron transition metal coordination complexes such as Kaihei 7-306527 and JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

Examples of the oxime ester compounds include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995).
202-232, a compound described in JP-A No. 2000-66385, a compound described in JP-A No. 2000-80068, specifically, a compound represented by the following structural formula.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt described in J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
The onium salts preferably used in the present invention are represented by the following general formulas (RI-I) to (RI-II).
An onium salt represented by I).

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. C2-C12 alkenyl group, C2-C12 alkynyl group, C6-C12 aryl group, C1-C12 alkoxy group, C6-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C2-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 6 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, alkenyl groups having 2 to 12 carbon atoms, alkynyl groups having 2 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, aryloxy groups having 6 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C2-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 6 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, carboxylate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 6 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 2 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 6 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  The polymerization initiator is not limited to the above, but an organic halogen compound, an oxime ester compound, a diazonium salt, an iodonium salt, and a sulfonium salt are more preferable particularly from the viewpoint of reactivity and stability.

  These polymerization initiators are preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the image recording layer. It can be added in proportions. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<(C) Binder polymer>
The image recording layer used in the lithographic printing plate precursor according to the invention contains (C) an oleophilic binder polymer that substantially does not contain an acid group. The binder polymer is used for improving the film strength and film properties of the image recording layer and for improving the dispersion stability in the ink of the image recording layer after on-press development. It is effective in improving the storage stability. In addition, being lipophilic improves solubility or dispersibility in oil-based ink and contributes to on-press development.

As the binder polymer, any conventionally known one can be used as long as it does not substantially contain an acid group, but a linear organic polymer having film properties is preferred.
Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.

The binder polymer preferably has crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.
Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and — (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom or an alkyl group having 1 to 20 carbon atoms,
Represents an aryl group, an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may be bonded to each other to form a ring; n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. ).
Specific examples of the ester unsaturated bond bonded to the ester residue include —CH ₂ CH═CH ₂ (described in JP-B-7-21633), —CH ₂ CH ₂ O—CH ₂ CH. _{= CH 2, -CH 2 C (} CH 3) = CH 2, -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO- CH ₂ CH═CH ₂ and —CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the ester unsaturated bond bonded to the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH. ₂ -OCO-CH = CH ₂ and the like.

  In the case of a binder polymer having crosslinkability, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) are added to the crosslinkable functional group, and a polymerization chain of a polymerizable compound is formed directly between polymers. Through addition polymerization, a cross-link is formed between the polymer molecules and cured. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, per 1 g of the binder polymer. -7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

The binder polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The binder polymer can be synthesized by a conventionally known method. Solvents used in the synthesis include, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy. Examples include 2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, and water. These may be used alone or in combination of two or more.
As the radical polymerization initiator used for synthesizing the binder polymer, known compounds such as an azo initiator and a peroxide initiator can be used.

A binder polymer may be used independently or may be used in mixture of 2 or more types.
The content of the binder polymer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and preferably 30 to 70% by mass with respect to the total solid content of the image recording layer. Further preferred. Within this range, good image area strength and image formability can be obtained.
Further, (B) the polymerizable compound having a specific structure and (C) the binder polymer are preferably used in a mass ratio of 1/9 to 7/3.

<(D) Photothermal conversion agent>
When the lithographic printing plate precursor according to the invention is used as infrared laser photosensitivity, it is preferable to contain a photothermal conversion agent in the image recording layer. The photothermal conversion agent has a function of converting absorbed infrared rays into heat. The photothermal conversion agent used in the present invention is a dye or pigment having absorption at a wavelength of 760 to 1200 nm, and is a dye or pigment generally called an infrared absorber. As an infrared absorber used by this invention, what has an absorption maximum in wavelength 760-1200 nm is more preferable.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.

  Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, Methine dyes described in JP-A Nos. 58-181690 and 58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, etc., British Patent No. And cyanine dyes described in the specification of 434,875.

In addition, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also suitable. ) Pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59- 41363, 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US Pat. It is disclosed in the pentamethine thiopyrylium salt described in Japanese Patent No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702. Pyrylium compounds are also preferably used. Another example of a preferable dye is a near-infrared absorbing dye described in U.S. Pat. No. 4,756,993 as formulas (I) and (II).
Other preferable examples of the infrared absorbing dye of the present invention include specific indolenine cyanine dyes described in JP-A-2002-278057 as exemplified below.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and one particularly preferred example is a cyanine dye represented by the following general formula (I).

In general formula (I), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below.

Here, Xa ⁻ is defined in the same manner as Za ⁻ described later, and R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, or a halogen atom.

X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. Here, the hetero atom represents N, S, O, a halogen atom, or Se.
R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. In addition, Za ^-
Represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (I) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the recording layer coating solution. Fluorophosphate ions and aryl sulfonate ions.

Specific examples of the cyanine dye represented by formula (I) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

These photothermal conversion agents may be added to the same layer as other components, or another layer may be provided and added thereto. Moreover, it can also be included in a microcapsule and added.
As the addition amount, when the lithographic printing plate precursor is prepared, the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm of the image recording layer seems to be in the range of 0.3 to 1.2 by the reflection measurement method. Preferably, it is added in the range of 0.4 to 1.1. Within this range, a uniform polymerization reaction in the depth direction of the image recording layer proceeds, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the image recording layer can be adjusted by the amount of the photothermal conversion agent added to the image recording layer and the thickness of the image recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

<(E) Microcapsule>
In the present invention, as a method for incorporating the image recording layer constituents (A) to (D) and other components described later into the image recording layer, all or part of the constituent components are encapsulated in microcapsules. It can be contained in the image recording layer. The same component can be contained both inside and outside the microcapsule.
In order to obtain good on-press developability, the image recording layer preferably contains microcapsules. The component to be included is preferably a hydrophobic or lipophilic compound.

As a method of microencapsulating the above-mentioned image recording layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation as described in the specifications of U.S. Pat. Nos. 2,800,047 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, and 42. -46 method by interfacial polymerization, US Pat. No. 3,418,250, US Pat. No. 3,660,304, by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol wall A method using a material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, a urea-formaldehyde system or urea found in US Pat. Nos. 4001140, 4087376, and 4089802 Formaldehyde-resorcinol system A method using a forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and a monomer polymerization as shown in Japanese Patent Publication Nos. 36-9163 and 51-9079 In situ method, British Patent No. 930422, US Pat. No. 3,111,407 spray drying method, British Patent No. 952807, US Pat. No. 967074 specification, etc. It is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with 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. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said binder polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

<Other image recording layer components>
The image recording layer of the present invention can further contain various additives as required. These will be described below.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the image recording layer in order to promote on-press developability at the start of printing and to improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the image recording layer.

<Hydrophilic polymer>
In the present invention, a hydrophilic polymer is included in the on-press development for the purpose of improving the water absorption of the image recording layer, improving the dispersion stability of the constituent components, and improving the dispersibility in dampening water during on-press development. Can do.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

Specific examples 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, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The hydrophilic polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the image recording layer is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass based on the total solid content of the image recording layer.

<Colorant>
In the present invention, various compounds other than these may be added as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc. And dyes described in Japanese Patent No. 293247. In addition, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can also be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording layer.

<Bakeout agent>
In the image recording layer of the present invention, a compound that changes color by an acid or a radical can be added to produce a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass with respect to the total solid content of the image recording layer.

<Thermal polymerization inhibitor (polymerization inhibitor)>
In the image recording layer of the present invention, it is preferable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the image recording layer.
Examples of the thermal polymerization inhibitor 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-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the image recording layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer of the present invention, and the surface of the image recording layer is dried during the coating process. It may be unevenly distributed. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

<Plasticizer>
The image recording layer of the present invention may contain a plasticizer in order to improve the on-press developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the image recording layer.

<Inorganic fine particles>
The image recording layer of the present invention may contain inorganic fine particles for the purpose of improving the strength of the cured film in the image area and improving the on-press developability of the non-image area.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the image recording layer, sufficiently retains the film strength of the image recording layer, and hardly causes stains during printing. .
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the image recording layer.

<Low molecular hydrophilic compound>
The image recording layer of the present invention may contain a hydrophilic low molecular weight compound for improving on-press developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Examples thereof include organic carboxylic acids such as salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid and amino acids, and salts thereof.

<Sensitizer>
The image recording layer of the present invention can contain a sensitizer. The sensitizer can increase the photopolymerization rate by using in combination with the radical polymerization initiator,
It is effective when the present invention is a UV laser-sensitive lithographic printing plate precursor.

  Specific examples of such sensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, 9-fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, and 2-bromo-9. -Anthrone, 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9, 10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone , Xanthone, 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methylstyryl ketone, benzophenone, p- ( Dimethylamino) benzophenone (or mihi Keton), p- (diethylamino) benzophenone, and the like benzanthrone.

  Furthermore, preferred sensitizers in the present invention include compounds represented by the general formula (II) described in JP-B 51-48516.

In the formula, R ¹⁴ is an alkyl group (for example, methyl group, ethyl group, propyl group, etc.) or a substituted alkyl group (for example, 2-hydroxyethyl group, 2-methoxyethyl group, carboxymethyl group, 2-carboxyethyl group) Etc.). R ¹⁵ represents an alkyl group (eg, methyl group, ethyl group, etc.) or an aryl group (eg, phenyl group, p-hydroxyphenyl group, naphthyl group, thienyl group, etc.).

Z ² is a group of nonmetallic atoms necessary for forming a heterocyclic nucleus containing nitrogen, which is usually used in cyanine dyes, such as benzothiazoles (benzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, etc.), naphtho Thiazoles (such as α-naphthothiazole, β-naphthothiazole), benzoselenazoles (such as benzoselenazole, 5-chlorobenzoselenazole, 6-methoxybenzoselenazole), naphthoselenazoles (α-naphthelenazole) , Β-naphthselenazole, etc.), benzoxazoles (benzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, etc.) and naphthoxazoles (α-naphthoxazole, β-naphthoxazole, etc.).

Specific examples of the compound represented by the general formula (II) are those having a chemical structure combining these Z ² , R ¹⁴ and R ¹⁵ , and many exist as known substances. Therefore, it can be used by appropriately selecting from these known ones. Furthermore, preferable sensitizers in the present invention include merocyanine dyes described in JP-B-5-47095 and ketocoumarin compounds represented by the following general formula (III).

Here, R ¹⁶ represents an alkyl group such as a methyl group or an ethyl group.

  As the sensitizer, merocyanine dyes described in JP-A No. 2000-147763 can also be used.

  These sensitizers are preferably from 0.1 to 50 mass%, more preferably from 0.5 to 30 mass%, particularly preferably from 0.8 to 20 mass%, based on the total solid content constituting the image recording layer. Can be added.

<Formation of image recording layer>
The image recording layer of the present invention is applied by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include 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, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The image recording layer of the present invention can also be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.3 to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

[Support]
The support used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), 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 the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (electrochemical surface roughening treatment that dissolves the surface), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. However, in general, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion with the image recording layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

[Undercoat layer]
In the lithographic printing plate precursor according to the invention, particularly in the case of an on-press development type lithographic printing plate precursor, an undercoat layer can be provided between the image recording layer and the support, if necessary. Since the undercoat layer easily peels off the image recording layer from the support in the unexposed area, the on-press developability is improved. In addition, in the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, so that heat generated by exposure does not diffuse to the support and can be used efficiently, so that high sensitivity can be achieved. There are advantages.
As the undercoat layer, specifically, a silane coupling agent having an addition polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. Preferred examples include phosphorus compounds having an ethylenic double bond reactive group described in the publication.

The undercoat layer preferably has a crosslinkable group-containing compound. The compound preferably further has an adsorptive group.
As the most preferable undercoat layer constituting component, there is a polymer resin obtained by copolymerizing a monomer having an adsorbing group / a monomer having a hydrophilic group / a monomer having a crosslinkable group.

An essential component of the polymer undercoat is an adsorptive group on the surface of the hydrophilic support. The presence or absence of adsorptivity on the surface of the hydrophilic support can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, after the support coated with the test compound is sufficiently washed with a readily soluble solvent, the residual amount of the test compound that has not been removed by washing is measured to calculate the adsorbed amount of the support. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having support adsorptivity is a compound that remains at 1 mg / m ² or more even after the above-described washing treatment.

The adsorptive group on the hydrophilic support surface is a substance (eg, metal, metal oxide) or functional group (eg, hydroxyl group) present on the hydrophilic support surface and a chemical bond (eg, ionic bond, hydrogen bond). , Coordination bond, bond by intermolecular force). The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxyl group, a carboxyl _{group, -SO 3 H, -OSO 3 H} , -PO 3 H 2, -OPO 3 H 2, -
CONHSO ₂ -, - including and _{-COCH 2 COCH 3 - SO 2 NHSO} 2. A phosphoric acid group (—OPO ₃ H ₂ , —PO ₃ H ₂ ) is particularly preferred. These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. An ammonium group, a phosphonium group and a sulfonium group are preferred, an ammonium group and a phosphonium group are more preferred, and an ammonium group is most preferred.

  Particularly preferred examples of the monomer having an adsorptive group include compounds represented by the following formula (IV) or (V).

In the formula (IV) and the formula (V), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms. R ¹ , R ² and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferred is a hydrogen atom or a methyl group. R ² and R ³ are particularly preferably a hydrogen atom.
In the formula (IV), X is an oxygen atom (—O—) or imino (—NH—). X is more preferably an oxygen atom. In formula (IV) and formula (V), L is a divalent linking group. L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent A heterocyclic group, or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, R is an aliphatic group, an aromatic group; Or a combination with a heterocyclic group) or carbonyl (—CO—).

  The aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. The aliphatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aromatic group, and a heterocyclic group.

The number of carbon atoms in the aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. The aromatic group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an aliphatic group, an aromatic group, and a heterocyclic group.
The heterocyclic group preferably has a 5-membered or 6-membered ring as the heterocycle. The heterocycle may be condensed with another heterocycle, aliphatic ring or aromatic ring. The heterocyclic group may have a substituent. Examples of substituents include halogen atoms, hydroxyl groups, oxo groups (═O), thioxo groups (═S), imino groups (═NH), substituted imino groups (═N—R, R is an aliphatic group, aromatic Group or heterocyclic group), aliphatic group, aromatic group and heterocyclic group.

L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In Formula (IV) and Formula (V), Z is a functional group that adsorbs to the surface of the hydrophilic support. Y is a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is connected to Y to form a quaternary pyridinium group, Z is not essential because it exhibits adsorptivity itself.
The adsorptive functional group is as described above.
Examples of typical monomers represented by formula (IV) or (V) are shown below.

  Examples of the hydrophilic group of the undercoat polymer resin that can be used in the present invention include a hydroxy group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, and an amino group. Preferred examples include a group, an aminoethyl group, an aminopropyl group, an ammonium group, an amide group, a carboxymethyl group, a sulfonic acid group, and a phosphoric acid group. A monomer having these hydrophilic group and polymerizable group is used as a copolymerization component of the polymer resin.

  The undercoat polymer resin used in the present invention preferably has a crosslinkable group. The crosslinkable group can improve the adhesion with the image area. In order to impart crosslinkability to the polymer resin for the undercoat, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer or has a counter charge with the polar substituent of the polymer resin. It can be introduced by forming a salt structure with a compound having a substituent and an ethylenically unsaturated bond.

  Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ₁ ═CR ₂ R ₃ and — (CH ₂ CH ₂ O) ₂ —X (wherein R _{1 to} R ₃ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group. Represents an alkoxy group or an aryloxy group, and R ₁ and R ₂ or R ₃ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadi An enyl residue).
Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 NHCOO-CH 2 CH = CH 2, and - CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ OCO—CH═CH _2. Is mentioned.
As the monomer having a crosslinkable group of the polymer resin for undercoating, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the polymer resin for undercoat (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the polymer resin. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

The undercoat polymer resin preferably has a mass average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1000 or more, preferably 2000 to 250,000. It is more preferable that The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The undercoat polymer resin may be a random polymer, a block polymer, a graft polymer, or the like, but is preferably a random polymer.

  As the undercoat polymer resin of the present invention, a known resin having a hydrophilic group can also be used. Specific examples of such resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Homopolymers and copolymers of methacrylates, homopolymers of hydroxybutyl acrylate Copolymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide Polymers and copolymers, homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin A polyether etc. are mentioned.

The undercoat polymer resin may be used alone or in combination of two or more. Two or more compounds having a functional group that adsorbs to the surface of the hydrophilic support may be used in combination.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

[Back coat layer]
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Protective layer]
In the lithographic printing plate precursor of the present invention used in the lithographic printing method of the present invention, image recording is performed as necessary to prevent the occurrence of scratches in the image recording layer, to block oxygen, and to prevent ablation during high-illuminance laser exposure. A protective layer can be provided on the layer.
In the present invention, the exposure is usually performed in the atmosphere, but the protective layer is an image of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that inhibit the image forming reaction caused by exposure in the image recording layer. This prevents the recording layer from being mixed, and prevents the image formation reaction from being hindered by exposure in the air. Therefore, the properties desired for the protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion to the image recording layer, and It is preferable that it can be easily removed in the on-press development process after exposure. Various studies have been made on the protective layer having such characteristics, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

Examples of the material used for the protective layer include water-soluble polymer compounds that are relatively excellent in crystallinity. Specific examples include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic acid. Among these, when polyvinyl alcohol (PVA) is used as a main component, the best results are obtained for basic characteristics such as oxygen barrier properties and development removability. The polyvinyl alcohol may be partially substituted with an ester, ether or acetal as long as it contains an unsubstituted vinyl alcohol unit for providing the oxygen barrier property and water solubility necessary for the protective layer, and a part of the other You may have a copolymerization component.
Specific examples of the polyvinyl alcohol include those having a hydrolysis degree of 71 to 100 mol% and a polymerization degree in the range of 300 to 2400. Specifically, for example, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA- HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, and L-8 are mentioned.

The components of the protective layer (selection of PVA, use of additives, etc.), coating amount, etc. are appropriately selected in consideration of fogging properties, adhesion, scratch resistance, etc. in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of PVA (that is, the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), and the thicker the film thickness, the higher the oxygen barrier property, which is preferable in terms of sensitivity. . Further, in order to prevent unnecessary polymerization reaction during production and storage and unnecessary fogging during image exposure, image line weighting, and the like, it is preferable that the oxygen permeability is not excessively high. Accordingly, the oxygen permeability A at 25 ° C. and 1 atm is preferably 0.2 ≦ A ≦ 20 (cc / m ² · day).

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the water-soluble polymer compound, and flexibility can be imparted. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers based on water-soluble polymer compounds Mass% can be added.

  In addition, adhesion of the protective layer to the image area, scratch resistance, and the like are extremely important in handling the lithographic printing plate precursor. That is, when a protective layer that is hydrophilic because it contains a water-soluble polymer compound is laminated on an image recording layer that is oleophilic, the protective layer is easily peeled off due to insufficient adhesion, and polymerization is inhibited by oxygen at the peeled portion. It may cause defects such as poor film hardening due to.

  On the other hand, various proposals have been made to improve the adhesion between the image recording layer and the protective layer. For example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, etc. in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on an image recording layer. Any of these known techniques can be used in the present invention.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of light used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

The thickness of the protective layer is suitably from 0.1 to 5 μm, particularly preferably from 0.2 to 2 μm.
The method for applying the protective layer is described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

[Lithographic printing method]
In the present invention, the image recording layer coated and formed on the support is exposed to the original image by exposing it through a transparent original image having a line image, a halftone dot image, etc. or imagewise exposure with a laser or the like by digital data. Give a relief image of the negative. Examples of light sources suitable for exposure include carbon arc lamps, mercury lamps, xeno lamps, metal hydrado lamps, strobes, ultraviolet rays, infrared rays, and laser beams. A laser beam is particularly preferable, and examples thereof include solid-state lasers and semiconductor lasers that emit infrared rays of 760 to 1200 nm, and blue-violet semiconductor lasers called violet lasers.

In the lithographic printing method of the present invention, as described above, after exposing the lithographic printing plate precursor of the present invention imagewise with a laser, the oil-based ink and the aqueous component are supplied without any development processing steps. Print.
Specifically, after a lithographic printing plate precursor is exposed with a laser, it is mounted on a printing machine without passing through a development process, and after printing the lithographic printing plate precursor on a printing machine, a laser is used on the printing machine. And a method of printing without passing through a development processing step.

After the lithographic printing plate precursor is imagewise exposed with a laser, printing is performed by supplying an aqueous component and an oil-based ink without passing through a development processing step such as a wet development processing step. The image recording layer cured by the above process forms an oil-based ink receiving portion having an oleophilic surface. On the other hand, in the unexposed area, the uncured image recording layer is dissolved or dispersed and removed by the supplied aqueous component and / or oil-based ink, and a hydrophilic surface is exposed in that area.
As a result, the aqueous component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the image recording layer in the exposed area, and printing is started. Here, the water-based component or the oil-based ink may be supplied to the printing plate first, but the oil-based ink is first used to prevent the water-based component from being contaminated by the image recording layer in the unexposed area. It is preferable to supply. As the aqueous component and oil-based ink, a dampening water and printing ink for ordinary lithographic printing are used.
In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Examples 1-8]
1. Preparation of lithographic printing plate precursor (1) Preparation of support In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a 10 mass% sodium aluminate aqueous solution is used at 50 ° C for 30 seconds. After degreasing, the aluminum surface is grained using ^three bundled nylon brushes with a bristle diameter of 0.3 mm and a pumice-water suspension with a median diameter of 25 μm (specific gravity 1.1 g / cm ³ ) Washed well with. This plate is 45 ° C
Etching was performed by immersing in 25% by weight sodium hydroxide aqueous solution for 9 seconds, washing with water, further immersing in 20% by weight nitric acid at 60 ° C. for 20 seconds, and washing with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Furthermore, in a 0.5% by mass aqueous solution of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C., nitric acid electrolysis is performed under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. An electrochemical surface roughening treatment was performed in the same manner, followed by washing with water by spraying. The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolyte, then washed with water and dried. A support A was obtained. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

  Next, the support A was immersed in an aqueous solution heated to 75 ° C. having a pH of 3.7 containing 0.1% by mass of sodium zirconate fluoride and 1% by mass of sodium dihydrogen phosphate for 10 seconds to seal the substrate. did. Then, it processed at 30 degreeC for 10 second with 2.5 mass% sodium silicate aqueous solution.

Furthermore, the following undercoat liquid (1) was applied so that the dry coating amount was 10 mg / m ² to prepare a support used in the following experiments.

Undercoat liquid (1)
・ Undercoat compound (1) below 0.017g
・ Methanol 9.00 g
・ Water 1.00g

(2) Formation of image recording layer After coating the image recording layer coating solution (1) having the following composition on the support having the above-mentioned undercoat layer, it was oven-dried at 100 ° C for 60 seconds, and the dry coating amount A 1.0 g / m ² image recording layer was formed to obtain a lithographic printing plate precursor.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microcapsule solution (1) immediately before coating.

Photosensitive solution (1)
・ Polymethyl methacrylate (mass average molecular weight 120,000) 0.385 g
・ The following polymerization initiator (1) 0.100 g
・ The following infrared absorber (1) 0.020 g
-EO chain-containing polymerizable compound shown in Table 1 Addition amount shown in Table 2-Fluorosurfactant 0.044g
MegaFuck F-176 (Dainippon Ink Chemical Co., Ltd.)
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

Microcapsule liquid (1)
・ Microcapsule synthesized as follows (1) 2.640 g
・ Water 2.425g

Synthesis of Microcapsule (1) As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemicals, Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd.) SR444) 3.15 g, 0.35 g of the following infrared absorber (2), 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane (ODB manufactured by Yamamoto Kasei Co., Ltd.), And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

[Comparative Example 1]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 except that the comparative substance (1) was used instead of the polymerizable monomer (1) used in the photosensitive solution (1).

[Comparative Example 2]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 except that half of the polymerizable monomer (1) used in the photosensitive solution (1) was replaced with the comparative substance (2).

2. Evaluation of Planographic Printing Plate Precursor The obtained lithographic printing plate precursor was exposed under conditions of an output of 9 W, an external drum rotation speed of 210 rpm, and a resolution of 2400 dpi with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser. The exposure image includes a thin line chart. The exposed exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink and Chemicals, Inc.) After supplying dampening water and ink, 1000 sheets were printed at a printing speed of 6000 sheets per hour.

  When the on-press development of the unexposed part of the image recording layer was completed on the printing press and the number of printing papers required until the ink was not transferred to the printing paper was measured as on-press developability, Even when the planographic printing plate precursor was used, a printed matter having no non-image area stain was obtained within 1000 sheets.

In general, in the case of a negative lithographic printing plate precursor, if the degree of cure of the image recording layer is too low, the printing durability of the lithographic printing plate is lowered, and the reproducibility of small dots and fine lines is poor. On the other hand, when the degree of cure of the image recording layer is high, the printing durability is high, and the reproducibility of small dots and fine lines is good.
In this example, as shown in Table 3, the sensitivity of the lithographic printing plate precursor was determined by evaluating the fine line reproducibility of the negative lithographic printing plate precursor. That is, it can be said that the sensitivity of the lithographic printing plate precursor is higher as the fine line width in the fine line reproducibility is thinner. Observe the thin line chart (10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100, and 200 μm wide thin line chart) of printed matter with a 25X magnifier The fine line reproducibility was evaluated by the fine line width reproduced with ink. The results are shown in Table 3.

  Next, the preservation ability of the lithographic printing plate precursor was evaluated. Assuming that the lithographic printing plate precursor was stored in a harsh state, using a constant temperature and humidity machine PR-3G manufactured by Tabai Espec Co., Ltd., 35 ° C., 50% R.D. H. In an environment of 1 month. Thereafter, exposure and printing were performed in the same manner as described above. As a result, only the sample of Comparative Example 1 was not completely developed even after printing 1000 sheets, and ink smearing occurred. The results are shown in Table 3.

  As is apparent from Table 3, the lithographic printing plate precursors (Examples 1 to 8) of the present invention have improved storage stability compared to the cases where the conventional lithographic printing plate precursors were used (Comparative Examples 1 and 2). It can be seen that fine line reproducibility is improved.

[Examples 9 to 18 and Comparative Example 3]
An image recording layer coating liquid (2) having the following composition was bar-coated on a support having the same undercoat layer as in Examples 1 to 8, and then oven-dried at 100 ° C. for 60 seconds to obtain a dry coating amount of 1.0 g. A lithographic printing plate precursor was obtained by forming an image recording layer of / m ² .
The image recording layer coating solution (2) was obtained by mixing and stirring the following photosensitive solution (2) and the microcapsule solution (1) immediately before coating.

Photosensitive solution (2)
・ Polymethylmethacrylate (mass average molecular weight 120,000) 0.218g
・ The above polymerization initiator (1) 0.100 g
・ The above infrared absorber (1) 0.020 g
-Polymerizable compound shown in Table 5 (structure is described in Table 4) 0.162 g
・ Fluorine-based surfactant 0.044g
MegaFuck F-176 (Dainippon Ink & Chemicals, Inc., methyl ethyl ketone 1.091 g
・ 1-methoxy-2-propanol 8.609g

Microcapsule liquid (1)
・ The above microcapsule (1) 2.640 g
・ Water 2.425g

The obtained lithographic printing plate precursor was exposed in the same manner as in Examples 1-8. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening solution (EU-3 (Etch solution manufactured by Fuji Photo Film Co., Ltd.) / Water / Isopropyl alcohol = 1/89/10 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.) After the plate cylinder was rotated 40 times by supplying dampening water, 1000 sheets were printed at a printing speed of 6000 sheets per hour at the same time as the ink was supplied.
The fine line reproducibility was evaluated in the same manner as in Examples 1-8. Ink fillability and printing durability were evaluated as follows. The evaluation results are shown in Table 5.

(Ink fillability)
After printing starts, ink gradually adheres to the image recording layer, and as a result, the ink density on the paper
Rise. The number of printed sheets when the ink density reached the standard printed matter density was evaluated as ink depositability.
(Print life)
After printing for evaluating fine line reproducibility, printing was further continued. As the number of printed sheets increased, the image recording layer was gradually worn out and the ink receptivity was lowered, so the ink density in the printing paper decreased. Printing durability was evaluated based on the number of printed sheets when the ink density (reflection density) decreased by 0.1 from the start of printing.

  As is apparent from Table 5, the lithographic printing plate precursors (Examples 9 to 18) of the present invention have printing durability and fine line reproducibility as compared with the case of using a conventional lithographic printing plate precursor (Comparative Example 3). It can be seen that the ink inking property is improved. Further, since the printing durability and fine line reproducibility are good, it can be said that the sensitivity is also good.

[Examples 19 to 22 and Comparative Examples 4 and 5]
On the support having the same undercoat layer as in Examples 1 to 8, the image recording layer coating solution shown in Table 6 below was bar coated, followed by oven drying at 100 ° C. for 60 seconds, and a dry coating amount of 1.0 g / An m ² image recording layer was formed to obtain lithographic printing plate precursors of Examples 19 to 22 and Comparative Examples 4 and 5.

Synthesis of Microcapsule (2) As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemicals, Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd.) SR444) 3.15 g, 0.35 g of the above infrared absorber (1), 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane (ODB manufactured by Yamamoto Kasei Co., Ltd.), And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

Examples 23 and 24
An overcoat layer coating solution having the following composition was bar-coated on the image recording layers of Examples 21 and 22, respectively, followed by oven drying at 100 ° C. for 90 seconds, and an overcoat layer having a dry coating amount of 0.1 g / m ^2. To obtain lithographic printing plate precursors of Examples 23 and 24.

Overcoat layer coating solution-Polyvinyl alcohol (PVA-105, manufactured by Kuraray Co., Ltd. (saponification degree 98 mol%, polymerization degree 500) 6.0 g
・ EMALEX 710 (manufactured by Nippon Emulsion Co., Ltd., surfactant) 0.1 g
・ Polyvinylpyrrolidone K30 0.2g
・ Rubitech VA64 (copolymer of 6: 4 ratio of vinyl pyrrolidone and vinyl acetate manufactured by BASF) 0.2 g
・ Water 100.0g

[Comparative Example 6]
On the image recording layer of Comparative Example 5, the overcoat layer coating solution having the above composition was bar-coated, followed by oven drying at 100 ° C. for 90 seconds to form an image recording layer having a dry coating amount of 0.1 g / m ^2. Thus, a planographic printing plate precursor of Comparative Example 3 was obtained.

  The obtained lithographic printing plate precursor was exposed under the same conditions as in Examples 1-8. The exposed exposed original plate was attached to a cylinder of a Sprint 25 printing machine manufactured by Komori Corporation without developing. Using the fountain solution shown in Table 8 and TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), after supplying the fountain solution and ink, the printing speed was 8000 sheets per hour. When printing was performed, on-press development was performed, and a good printed matter without stains was obtained. The fountain solution used was a product obtained by diluting IF-102 manufactured by Fuji Photo Film to a concentration of 4% by volume with tap water.

The printing machine was stopped at the 500th sheet, and the adhesion state of the removed image recording layer (removed residue) on the swim roller was evaluated. The indicators are as follows.
○: No debris is seen on the swim roller △: A small amount of debris is seen on the swim roller x: Many debris are seen on the swim roller

  After the evaluation of residue adhesion, printing was continued and printing durability was evaluated in the same manner as in Examples 9-18. The evaluation results are summarized in Table 8.

  As is apparent from Table 8, the lithographic printing plate precursors of the present invention (Examples 19 to 24) are on the swim roller as compared with the case of using the conventional lithographic printing plate precursors (Comparative Examples 4 to 6). The adhesion state and printing durability of the image recording layer removal residue are extremely excellent.

Claims (8)

  On the support, (A) a radical polymerization initiator, (B) a polymerizable compound, and (C) a lipophilic binder polymer substantially free of acid groups, printing ink, fountain solution, or both A lithographic printing plate precursor having an image-recording layer removable by the method, wherein the polymerizable compound is at least selected from (1) an ethylene oxide chain, (2) an alcoholic hydroxyl group, and (3) an isocyanuric acid structure in the molecule. A lithographic printing plate precursor having a single structure.   2. The lithographic printing plate precursor as claimed in claim 1, wherein the image recording layer further comprises (D) a photothermal conversion agent.   The lithographic printing plate precursor according to claim 1 or 2, wherein the support has an undercoat layer containing a crosslinkable group-containing compound.   The lithographic printing plate precursor according to claim 3, wherein the crosslinkable group-containing compound further has an adsorptive group.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the image recording layer further comprises (E) a microcapsule.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, further comprising a protective layer on the image recording layer.   The lithographic printing plate precursor as claimed in claim 6, wherein the protective layer has a thickness of 0.1 to 5 µm.   The planographic printing plate precursor according to any one of claims 1 to 7 is mounted on a printing press and imagewise exposed with a laser, or imagewise exposed with a laser and then mounted on a printing press. A lithographic printing method in which printing ink and fountain solution are supplied to the lithographic printing plate precursor to remove a laser unexposed portion of the image recording layer and perform printing.