JP2006256040A - Original lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original lithographic printing plate which can allow an image to be formed in itself without an alkali development procedure after laser exposure and has successful fine line reproducibility, resistance to plate wear, less susceptibility of contamination, aboard-the-machine developability and shelf stability. <P>SOLUTION: This original lithographic printing plate comprises a photopolymerization layer with laser sensitivity formed on a support and can allow an image to be formed in itself without an alkali development procedure. In addition, the printing plate comprises a copolymer having (a1) a repeating unit with a radical chain crosslinking group and (a2) a repeating unit with a functional group taking an interacting effect with the surface of the support, in the photopolymerization layer or another layer positioned between the support and the photopolymerization group. Further, the copolymer preferably has (a3) a repeating unit with a hydrophilic group. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a so-called lithographic printing plate precursor capable of direct plate making, which can be directly made by scanning a laser having a wavelength of, for example, 300 to 1200 nm based on a digital signal from a computer or the like.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the 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 a 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 an unnecessary image recording layer is dissolved with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by performing the plate making by removing the surface of the hydrophilic support to form a non-image portion.

  In the conventional plate making process of a lithographic printing plate precursor, a step of dissolving and removing an unnecessary image recording layer with a developer or the like is required after exposure. However, such additional wet processing is 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.

On the other hand, as one simple plate making method, an image recording layer that can remove an unnecessary portion of an image recording layer of a lithographic printing plate precursor in a normal printing process is used. A method called on-press development has been proposed in which unnecessary portions are 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 , A method of mechanically removing the image recording layer by contact with rollers or a blanket cylinder of a printing press, cohesion of the image recording layer by penetration of dampening water, ink solvent, etc. There is a method in which after the adhesive force is weakened, the image recording layer is mechanically removed by contact with rollers or a blanket cylinder.
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 the step of removing the laser unexposed portion 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 printing ink) using a printing press. It refers to a method and a process for removing the laser unexposed portion of the lithographic printing plate precursor and exposing the surface of the hydrophilic support by contacting with dampening water.

  On the other hand, in recent years, digitization techniques for electronically processing, storing, and outputting image information using a computer have become widespread, and various new image output methods corresponding to such digitization techniques have been put into practical use. It is becoming. 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 (CTP) technology has been attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

Among the lithographic printing plate precursors, the lithographic printing plate precursor capable of scanning exposure is an oleophilic photosensitive resin containing a photosensitive compound capable of generating active species such as radicals and Bronsted acids on a hydrophilic support by laser exposure. Tiers have been proposed and are already on the market. This lithographic printing plate precursor is laser-scanned based on digital information to generate active species, which causes physical or chemical changes in the photosensitive layer to insolubilize it, followed by development processing, thereby developing a negative lithographic printing plate Can be obtained. In particular, a photopolymerization type photosensitive layer containing a photopolymerization initiator excellent in photosensitive speed on a hydrophilic support, an addition-polymerizable ethylenically unsaturated compound, and a binder polymer soluble in an alkali developer, and necessary A lithographic printing plate precursor provided with an oxygen-blocking protective layer in accordance with the printing plate having desirable printing performance due to advantages such as excellent productivity, simple development processing, and good resolution and inking properties. It can be.
Further, as an on-press developable lithographic printing plate, for example, in Patent Document 1, an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. A planographic printing plate precursor is described. 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.
In this way, the method of forming an image by merging by simple thermal fusion of fine particles shows good on-press developability, but the image strength (adhesion with the support) is extremely weak and the printing durability is insufficient. Had the problem of being.

Moreover, a lithographic printing plate precursor comprising microcapsules encapsulating a polymerizable compound on a hydrophilic support has been proposed (see, for example, Patent Documents 2 to 3).
Furthermore, a lithographic printing plate precursor having a photosensitive layer containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound on a support has been proposed (see, for example, Patent Document 4).
As described above, the method using the polymerization reaction has a feature that the image strength is relatively good because the chemical bond density of the image portion is higher than that of the image portion formed by thermal fusion of the polymer fine particles.

  However, since the polymerization type photosensitive layer does not necessarily have a strong adhesive force with the support, when used for printing a large number of copies at a high speed, a solid image may be lost, or fine lines and highlights may be thinned or skipped. Arise. Therefore, in high-sensitivity photopolymerization systems, photoadhesiveness between the support and the photosensitive layer is an important factor, and many researches and developments have been made.

For example, it is known to provide a polymer having a polymerizable group having an ethylenically unsaturated bond and a phosphate group between the polymerization type photosensitive layer and the support (see Patent Document 5). In addition, a technique is also known in which a functional group capable of causing an addition reaction due to a radical is provided on the support surface by a covalent bond so as to have an adhesive force with the photopolymerizable photosensitive layer (for example, Patent Documents 6 to 6). 8).
A photosensitive layer and a support comprising a compound obtained by hydrolyzing and dehydrating and condensing a silane coupling agent having an ethylenic double bond, and a compound containing an alkylene oxide chain and an acryloyl group or a methacryloyl group in one molecule. It is also known to provide between (see Patent Document 9).

In addition, a technique for improving adhesion to a support by adding a phosphate ester compound having a (meth) acryloyl group to a photosensitive layer is also known (see Patent Document 10).
Japanese Patent No. 2938397 JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A JP-A-2-304441 Japanese Patent Laid-Open No. 3-56177 Japanese Patent Laid-Open No. 7-159838 JP-A-8-320551 Japanese Patent Laid-Open No. 10-282679 Japanese Patent Laid-Open No. 11-30858

  However, from the practical point of view, these conventional techniques are still insufficient in any of fine line reproducibility, printing durability, stain resistance, on-press developability and storage stability, and further improvement is desired. Mareta. The object of the present invention is to respond to this, and it is possible to form an image without laser development after laser exposure, and any of fine line reproducibility, printing durability, resistance to stains, on-press developability and storage stability. It is to provide a good planographic printing plate precursor.

As a result of intensive studies, the present inventor has found that the above-described problems can be satisfied by incorporating a specific copolymer into the photopolymerization layer or the layer between the photopolymerization layer and the support.
The present invention is as follows.

1. A lithographic printing plate precursor having a laser-sensitive photopolymerization layer on a support and capable of forming an image without alkali development, wherein the other layer located in the photopolymerization layer or between the support and the photopolymerization layer (A1) a repeating unit having at least one radical chain crosslinkable group represented by the following general formula (A1); and (a2) a repeating unit having at least one functional group that interacts with the support surface; A lithographic printing plate precursor comprising a copolymer having:
—C (R ₁ ) (R ₂ ) —C (R ₃ ) (L—X—H) — General Formula (A1)
(In the formula, X represents a group having a bond dissociation energy of XH at 25 ° C. of 95 kcal / mol [398 kJ / mol] or less. L is a divalent linking group, R _{1 to} R ₃ are hydrogen atoms, (It represents a hydrocarbon group or halogen atom which may have a substituent having 1 to 6 carbon atoms.)

  2. 2. The lithographic printing plate precursor as described in 1 above, wherein the polymer compound is a copolymer having (a3) a repeating unit having at least one hydrophilic group in the molecule.

  3. 3. The lithographic printing plate precursor as described in 1 or 2 above, wherein the support is anodized aluminum and a chemical surface modification product thereof.

  4). 4. The lithographic printing plate precursor as described in any one of 1 to 3 above, wherein the photopolymerization layer contains an infrared absorber.

  5. 5. The lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the photopolymerizable layer contains microcapsules.

The problem of the present invention has been solved by including a specific copolymer in the photopolymerization layer or in the layer between the photopolymerization layer and the support. Although the mechanism is not clear, the copolymer of the present invention adheres to the support by an interaction group with the support and has a structure represented by the general formula (A1) having a high chain crosslinking property. The exposed portion has an effect of improving adhesion by photopolymerization layer and polymerization chain crosslinking. On the other hand, in terms of stain resistance and developability, it is considered that the hydrogen bonding property of the general formula (A1) increases the affinity for printing dampening water and improves stain resistance and developability.
Furthermore, since it has a hydrophilic group in the same molecule, it can be seen that the stain resistance and developability are dramatically improved, and it acts synergistically with the previous adhesion effect.
The function of the polymer compound of the present invention is particularly suitable for heat mode exposure by infrared laser exposure of 800 nm or more. The chain cross-linking reaction of the polymer is accelerated by heating and the molecular motion becomes active. Therefore, heat mode exposure in which heat is generated in the laser exposure portion and polymerization is performed is more preferable than photon mode exposure.
As described above, the lithographic printing plate precursor according to the present invention in which the image intensity on the printing machine in the exposed area and the developability on the printing machine in the unexposed area are compatible is particularly suitable as an unprocessed lithographic printing plate. Can be used.

  According to the present invention, a lithographic printing plate that can form an image without laser development after laser exposure and has good fine line reproducibility, printing durability, resistance to stains, on-press developability, and storage stability. The original edition can be provided.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the present invention is a lithographic printing plate precursor having a laser-sensitive photopolymerization layer on a support and capable of forming an image without alkali development, in the photopolymerization layer or the support. In another layer located between the photopolymerization layers, (a1) a repeating unit having at least one radical chain crosslinkable group represented by the general formula (A1), and (a2) a function that interacts with the support surface And a copolymer having a repeating unit having at least one group (hereinafter, also referred to as “specific copolymer”). The specific copolymer of the present invention preferably further has (a3) a repeating unit containing at least one hydrophilic group.

[Specific copolymer]
As the specific copolymer, those containing a repeating unit represented by the following formula (I) are preferable.

In formula (I), A ₁ represents a repeating unit containing at least one radical chain crosslinkable group represented by the following general formula (A1), and A ₂ represents at least 1 functional group that interacts with the support surface. A ₃ represents a repeating unit having at least one hydrophilic group. x, y, z represents a copolymerization ratio.

—C (R ₁ ) (R ₂ ) —C (R ₃ ) (L—X—H) — General Formula (A1)
(In the formula, X represents a group having a bond dissociation energy of XH at 25 ° C. of 95 kcal / mol [398 kJ / mol] or less. L is a divalent linking group, R _{1 to} R ₃ are hydrogen atoms, (It represents a hydrocarbon group or halogen atom which may have a substituent having 1 to 6 carbon atoms.)

Preferable examples of XH in the general formula (A1) include the following.
-SH General formula (A1-1)
-ArOH Formula (A1-2)
(In the formula, Ar represents an aromatic ring or a heteroaromatic ring.
—Z—CH (R ¹ ) —C (═O) —Y Formula (A1-3)
(In the formula, R ¹ represents a hydrogen atom, a hydrocarbon group, —W—R ³ — (W represents a heteroatom, R ³ represents a hydrocarbon group), a halogen atom or —COR ⁴ (R ⁴ represents a hydrocarbon group. Y represents a hydrocarbon group which may contain a hetero atom, Y may be a linking group and may be linked to R ¹ to form a ring, and Z is —C. (= O) —, —S—, —O—, or a divalent linking group represented by —NR ² —, R ² represents a hydrogen atom or a hydrocarbon group.
—CH (Ar) —Y Formula (A1-4)
(In the formula, Ar represents an aromatic ring or a heteroaromatic ring. Y represents a hydrocarbon group which may contain a hetero atom.)

  In general formula (A1), L represents a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. To express.

Specific examples of L composed of combinations are given below. In the following examples, the left side is bonded to the main chain, and the right side is bonded to the ethylenically unsaturated bond.
L1: -CO-NH-divalent aliphatic group -O-CO-
L2: —CO—divalent aliphatic group —O—CO—
L3: -CO-O-divalent aliphatic group -O-CO-
L4: -Divalent aliphatic group -O-CO-
L5: -CO-NH-divalent aromatic group -O-CO-
L6: -CO-divalent aromatic group -O-CO-
L7: -Divalent aromatic group -O-CO-
L8: -CO-divalent aliphatic group-CO-O-divalent aliphatic group-O-CO-
L9: -CO-divalent aliphatic group-O-CO-divalent aliphatic group-O-CO-
L10: -CO-Divalent aromatic group -CO-O-Divalent aliphatic group -O-CO-
L11: -CO-Divalent aromatic group -O-CO-Divalent aliphatic group -O-CO-
L12: -CO-divalent aliphatic group-CO-O-divalent aromatic group-O-CO-
L13: -CO-Divalent aliphatic group -O-CO-Divalent aromatic group -O-CO-
L14: -CO-divalent aromatic group-CO-O-divalent aromatic group-O-CO-
L15: -CO-Divalent aromatic group -O-CO-Divalent aromatic group -O-CO-
L16: -CO-O-divalent aromatic group -O-CO-NH-divalent aliphatic group -O-CO-
L17: -CO-O-divalent aliphatic group -O-CO-NH-divalent aliphatic group -O-CO-

The divalent aliphatic group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, a substituted alkynylene group or a polyalkyleneoxy group. Of these, an alkylene group, a substituted alkylene group, an alkenylene group, and a substituted alkenylene group are preferable, and an alkylene group and a substituted alkylene group are more preferable.
The divalent aliphatic group is preferably a chain structure rather than a cyclic structure, and more preferably a linear structure than a branched chain structure.
The number of carbon atoms in the divalent aliphatic group is preferably 1 to 20, more preferably 1 to 15, further preferably 1 to 12, and further preferably 1 to 10. It is preferably 1 to 8, and most preferably.
Examples of the substituent of the divalent aliphatic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, an amino group, a cyano group, an aryl group, an alkoxy group, an aryloxy group, and an acyl group. , Alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, monoalkylamino group, dialkylamino group, arylamino group and diarylamino group.

The divalent aromatic group means an arylene group or a substituted arylene group. Preferable are phenylene, substituted phenylene group, naphthylene and substituted naphthylene group.
Examples of the substituent for the divalent aromatic group include an alkyl group in addition to the examples of the substituent for the divalent aliphatic group.
Among L1 to L17, L1, L3, L5, L7, and L17 are preferable.

In the formula (I), the repeating unit represented by A ₂ is specifically represented by the following formula (A2).

In formula, R < ₁ > -R < ₃ > and L are synonymous with what is represented by said Formula (A1). Q represents a functional group that interacts with the support surface (hereinafter sometimes abbreviated as “specific functional group”).
Specific functional groups include, for example, covalent bonds, ionic bonds, hydrogen bonds, polar interactions, van der Waals interactions with metals, metal oxides, hydroxyl groups, etc. present on an anodized or hydrophilized support. Examples include groups capable of interaction such as action.
Specific examples of the specific functional group are listed below.

(In the above formula, R _{11 to} R ₁₃ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkynyl group, or an alkenyl group, and M ₁ and M ₂ each independently represent a hydrogen atom, a metal atom, or Represents an ammonium group, and X ⁻ represents a counter anion.)
Among these, the specific functional group is preferably an onium base such as an ammonium group or a pyridinium group, or a β-diketone group such as a phosphate group, a phosphonic acid group, a boric acid group, or an acetylacetone group.

In the formula (A2), L represents a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. .
Specific examples of L composed of combinations include the following in addition to the specific examples of L in (A1). In the following examples, the left side is bonded to the main chain.
L18: —CO—NH—
L19: -CO-O-
L20: -Divalent aromatic group-

In the formula (I), the repeating unit represented by A ₃ is preferably represented by the following formula (A3).

In formula, R < ₁ > -R < ₃ > and L are synonymous with what is represented by said Formula (A1). W represents the following group.

However, M ₁ is the same meanings as those represented in the description of the formula (A2).
R ₇ and R ₈ each independently represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms.
R ₉ represents a linear or branched alkylene group having 1 to 6 carbon atoms, preferably an ethylene group.
R ₁₀ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.
n represents an integer of 1 to 100, and preferably 1 to 30.

The repeating unit containing at least one of the hydrophilic groups represented by (A3) preferably has a log P of -3 to 3, more preferably -1 to 2. Within this range, good developability can be obtained.
Here, logP is developed by Medicinal Chemistry Project, Pomona College, Clarmont, California, Daylight Chemical Information Inc. It is the logarithm of the octanol / water partition coefficient (P) value of a compound calculated using the more available software PCModels.
The W preferably contains an alkyleneoxy group.

  As a molecular weight of the said specific copolymer, the range of 500-100,000 is preferable at a mass mean molecular weight, and the range of 700-50,000 is more preferable. Further, (a1) is preferably from 5 to 80 mol%, more preferably from 10 to 50 mol%, based on all copolymerized monomers. (A2) is preferably from 5 to 80 mol%, more preferably from 10 to 50 mol%, based on all copolymerized monomers. Furthermore, (a3) is preferably from 5 to 80 mol%, more preferably from 10 to 50 mol%, based on all copolymerized monomers.

  Specific examples of the specific copolymer used in the present invention are shown below, but are not limited thereto.

In the present invention, the adsorptivity of the specific copolymer to the anodized aluminum film can be measured by the following method.
A coating solution in which a test compound is dissolved in a readily soluble solvent is prepared, and the coating solution is applied onto an aluminum support on which an anodized film has been applied so that the coating amount after drying is 30 mg / m ² and dried. Let After the support coated with the test compound is sufficiently washed with a readily soluble solvent, the amount of adsorption of the test compound that has not been removed by washing is measured. Here, the residual amount may be measured by directly quantifying the residual compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. As a method for quantifying the compound, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like can be performed. A compound having an adsorptivity to the aluminum anodic oxide film remains in an amount of 0.1 mg / m ² or more even after such a cleaning treatment.

  In the present invention, the specific copolymer can be used in the photopolymerization layer or in other layers. The other layer is preferably a layer adjacent to the support or the photopolymerization layer. Especially, it is especially preferable to use for the undercoat layer (intermediate layer) provided between a support body and a photopolymerization layer since the effect of this invention is fully exhibited. By using it as an undercoat layer, stronger adhesion between the support of the exposed portion and the photopolymerizable layer can be obtained, and in the unexposed portion, the photopolymerizable layer is easily peeled off from the support. Improves stain resistance. In the case of infrared exposure, since the undercoat layer functions as a heat insulating layer, the heat generated by the exposure by the infrared laser does not diffuse to the support and can be used efficiently, so that the sensitivity can be increased. There is also.

  In the present invention, when the specific copolymer is used for the undercoat layer, the copolymer is usually diluted with a solvent. Examples of the solvent include water and organic solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, hexylene glycol, tetrahydrofuran, dimethylformamide, 1-methoxy-2-propanol, dimethylacetamide, and dimethyl sulfoxide. Are preferred. These organic solvents can also be mixed and used.

As a density | concentration of undercoat layer coating liquid, 0.001-10 mass% is preferable, More preferably, it is 0.01-5 mass%, More preferably, it is 0.05-1 mass%. A surfactant described later may be added to the undercoat layer as necessary.

The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 3 to 30 mg / m ^2.

(Photopolymerization layer)
The lithographic printing plate precursor according to the invention has a laser-sensitive photopolymerization layer on a hydrophilic support. The photopolymerization layer can contain a binder polymer, an infrared absorber, a polymerization initiator, a sensitizing dye, a polymerizable compound, microcapsules and other additives depending on the design purpose of the lithographic printing plate precursor. Hereinafter, constituent components necessary for the photopolymerization layer will be described.

<Binder polymer>
As the binder polymer that can be used in the present invention, a polymer having a conventionally known film property can be used without limitation. However, in order to improve the film property of the photopolymerization layer and the on-machine developability, the binder polymer may be used in the molecule, specifically It is preferable to use a polymer compound having an ether group represented by the following formula (1) in the side chain.

  In formula (1), R represents a hydrogen atom or a methyl group, a is 1, 3 or 5, and 1 represents an integer of 1 to 9. l is preferably an integer of 1 to 8, more preferably an integer of 1 to 7, still more preferably an integer of 1 to 6, and most preferably an integer of 1 to 4.

The polymer compound having an ether group represented by the above formula (1) of the present invention in the molecule preferably has a glass transition temperature (Tg) of 90 ° C. or lower. From the viewpoint of improving the on-press developability and improving the polymerization efficiency by exposure, those less than 70 ° C. are more preferable. Moreover, although there is no restriction | limiting in particular in the minimum of Tg, -50 degreeC or more is preferable from a viewpoint of storage stability.
Here, “glass transition temperature” (Tg) is defined as “polymer chemistry” (Kyoritsu Shuppan, published in 1993) and is 2 2 when the specific volume of a polymer substance is measured as a function of temperature. It refers to the temperature corresponding to the intersection of the straight lines of the book, and adopts a value measured by a differential scanning calorimeter (DSC).

  Regarding the polymer compound according to the present invention, in order to set Tg to a desired value, a functional group having a linear partial structure may be introduced into the structural unit constituting the polymer compound, or one kind, or Such a functional group may be introduced into any one of two or more structural units depending on the purpose. For this reason, the main chain structure of the polymer compound according to the present invention is not particularly limited. Preferable examples of the main chain structure include poly (meth) acrylic resins, polyurethane resins, acetal-modified products of polyvinyl resins, and the like. Among them, poly (meth) acrylic resins are preferred from the viewpoint of printing performance such as ink setting properties. Resins are preferred. Therefore, in order to reduce the Tg of the polymer compound having such a poly (meth) acrylic main chain structure to 90 ° C. or less, the polymer compound has the structural unit represented by the general formula (1) as a side chain. It is necessary to contain. In this case, a plurality of different structural units may be contained.

  The polymer compound used as the binder of the present invention may have an ether group other than the ether group represented by the above formula (1).

The polymer compound used as the binder of the present invention may be copolymerized with a radically polymerizable compound having a hydrophilic group in order to improve various performances such as on-press developability. Such a hydrophilic group is preferably not an alkali-soluble group, such as an amide group, a hydroxyl group,
There are onium bases and the like, and an amide group and a hydroxyl group are preferable. Specific examples of the radical polymerizable compound having a hydrophilic group include, for example, acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, N-vinylpyrrolidone, N-vinylacetamide, N-acryloylmorpholine, 2 -Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate are mentioned. These may be used alone or in combination of one or more. The content of these copolymer components is preferably 0 to 85 mol%, particularly preferably 5 to 70 mol%.

  In order to improve various properties such as image strength, the polymer compound used as the binder of the present invention is not limited to the above-mentioned radical polymerizable compound, as long as the effects of the present invention are not impaired. It is also a preferred embodiment to copolymerize. Examples of the radical polymerizable compound that can be copolymerized with the polymer compound in the present invention include acrylic acid esters, methacrylic acid esters, N, N-2 substituted acrylamides, and N, N-2 substituted methacrylamides. , Radically polymerizable compounds selected from styrenes, acrylonitriles, methacrylonitriles and the like.

  Specifically, for example, acrylic esters such as alkyl acrylate (the alkyl group preferably has 1 to 20 carbon atoms) (specifically, for example, methyl acrylate, ethyl acrylate, acrylic Propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate , Pentaerythritol monoacrylate, glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, etc.), aryl acrylate (e.g., Methacrylic acid esters (for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, etc.) Cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate , Glycidyl methacrylate, furfuryl methacrylate, tetrahydroph Styrene such as methyl methacrylate, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, Butyl styrene, hexyl styrene, cyclohexyl styrene, decyl styrene, benzyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, etc.), alkoxy styrene (for example, methoxy styrene, 4-methoxy-3-methyl styrene, Dimethoxystyrene, etc.), halogen styrene (eg chlorostyrene, dichlorostyrene, trichloro) Styrene, tetrachlorostyrene, pentachlorostyrene, prom styrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene, etc. ), Acrylonitrile, methacrylonitrile and the like.

  The polymer compound used as the binder of the present invention may have an ester group represented by the following formula (2) or an amide group represented by the following formula (3) in the molecule.

  In the formula, b is an integer of 2 to 5, c is an integer of 2 to 7, and m and n each independently represents an integer of 1 to 100.

  Of these radical polymerizable compounds, acrylic acid esters, methacrylic acid esters, and styrenes are preferably used. These can be used singly or in combination of two or more. The content of these copolymerization components is preferably 0 to 95 mol%, particularly preferably 20 to 90 mol%.

  The polymer compound used as the binder according to the present invention may be a homopolymer, but radically polymerizable compounds having different groups represented by the general formula (1) or groups represented by the general formula (1). In the case of a copolymer of one or more radically polymerizable compounds having one or more of the above-mentioned other radically polymerizable compounds, the composition of the copolymer includes a block copolymer, a random copolymer, and a graft copolymer. Any of them may be combined.

  Examples of the solvent used for synthesizing such a polymer compound include ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, propanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxy. Examples include ethyl acetate, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, toluene, ethyl acetate, methyl lactate, and ethyl lactate. It is done. These solvents may be used alone or in combination of two or more.

  The polymer compound used as the binder according to the present invention has a mass average molecular weight Mw, preferably 2,000 or more, and more preferably 5,000 to 300,000. Further, the polymer compound according to the present invention may contain an unreacted monomer. In this case, the proportion of the monomer in the polymer compound is desirably 15% by mass or less. The content of the polymer compound used as the binder contained in the lithographic printing plate precursor according to the invention is preferably about 5 to 95% by mass, more preferably about 10 to 85% by mass in terms of solid content. Within this range, good image area strength and image formability can be obtained.

  Specific examples of structural units of the polymer compound used as the binder polymer in the present invention are shown below, but are not limited thereto.

<Infrared absorber>
When forming an image of the lithographic printing plate precursor according to the invention with a laser light source that emits infrared rays of 760 to 1200 nm, for example, it is preferable to contain an infrared absorber in the photopolymerization layer. The infrared absorber has a function of converting absorbed infrared rays into heat. Due to the heat generated at this time, a polymerization initiator (radical generator) described later is thermally decomposed to generate radicals. Examples of the infrared absorber used in the present invention include dyes or pigments having an absorption maximum at a wavelength of 760 to 1200 nm.

As the dye used as the infrared absorber, 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, 58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59- No. 73996, JP-A-60-52940, JP-A-60-63744 and the like, Naphthoquinone dyes described in JP-A-58-112792, etc., British Patent 434,875 And cyanine dyes.

Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. . Another example of a preferable dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.
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 preferable, and one particularly preferable example is a cyanine dye represented by the following general formula (i).

In formula (i), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below.

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. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.
X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² in the general formula (i) each independently represent 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. Z _a ^- represents a counter anion. However, when the cyanine dye represented by formula (i) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of storage stability of the recording layer coating solution. Hexafluorophosphate ion and aryl sulfonate ion.

Specific examples of the cyanine dye represented by formula (i) that can be suitably used in the present invention include those described in paragraphs [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 size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. Within this range, good stability of the pigment dispersion in the photopolymerization layer coating solution and good uniformity of the photopolymerization 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 infrared absorbers may be added to the same layer as other components, or may be added to another layer, but photopolymerization is performed when a negative lithographic printing plate precursor is prepared. The layer is added so that the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm is in the range of 0.3 to 1.2 by the reflection measurement method. Preferably, it is the range of 0.4-1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the photopolymerization layer, and good film strength of the image area and adhesion to the support can be obtained.
The light absorbency of a photopolymerization layer can be adjusted with the quantity of the infrared absorber added to a photopolymerization layer, and the thickness of a photopolymerization layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, a photopolymerization layer having a thickness appropriately determined as a lithographic printing plate precursor is applied on a coating amount after drying, and the reflection density is optically measured. Examples thereof include a method of measuring with a densitometer, a method of measuring with a spectrophotometer by a reflection method using an integrating sphere, and the like.

<Polymerization initiator>
As a polymerization initiator used in the photopolymerization layer of the present invention, various photopolymerization initiators known in patents, literatures, etc., or a combination system of two or more photopolymerization initiators depending on the wavelength of the light source used ( Photopolymerization initiation system) can be appropriately selected and used.

  In the case of using a blue semiconductor laser, Ar laser, second harmonic of an infrared semiconductor laser, or SHG-YAG laser as a light source, various photopolymerization initiators (systems) have been proposed. 850,445, certain photoreducible dyes such as rose bengal, eosin, erythrosine, etc., or combinations of dyes and initiators, such as complex initiator systems of dyes and amines. -20099), a combination system of hexaarylbiimidazole, a radical generator and a dye (Japanese Patent Publication No. 45-37377), a system of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (Japanese Patent Publication No. 47-2528). JP, 54-155292, cyclic cis-α-dicarbonyl compound and dye system (JP 48-8) 183), a system of cyclic triazine and merocyanine dye (Japanese Patent Laid-Open No. 54-151024), a system of 3-ketocoumarin and an activator (Japanese Patent Laid-Open No. 52-112682, Japanese Patent Laid-Open No. 58-15503) , Biimidazole, styrene derivative, thiol system (JP 59-140203 A), organic peroxide and dye system (JP 59-1504 A, JP 59-140203 JP, JP JP-A 59-189340, JP-A 62-174203, JP-B 62-1641, US Pat. No. 4,766,055), a system of dye and active halogen compound (JP-A 63-1718105, JP-A-63-258903, JP-A-3-264771, etc.), a system of a dye and a borate compound (JP-A-62-143044, Japanese Unexamined Patent Publication Nos. 62-150242, 64-13140, 64-13141, 64-13142, 64-13143, 64-13144 JP-A-64-17048, JP-A-1-229003, JP-A-1-298348, JP-A-1-138204, etc.), a system comprising a dye having a rhodanine ring and a radical generator ( JP-A-2-17943, JP-A-2-244050), titanocene and 3-ketocoumarin dye system (JP-A 63-221110), titanocene and xanthene dye, addition polymerization containing amino group or urethane group A combination of possible ethylenically unsaturated compounds (JP-A-4-221958, JP-A-4-219756), Tanosen and system specific merocyanine dye (JP-A-6-295061), a dye system with titanocene and benzopyran ring (JP-A-8-334897 JP), and the like.

  In the photopolymerization layer (photosensitive layer) of the lithographic printing plate precursor according to the invention, a particularly preferred photopolymerization initiator (system) contains at least one titanocene. The titanocene compound used as a photopolymerizable initiator (system) in the present invention may be any titanocene compound that can generate an active radical when irradiated with light in the presence of a sensitizing dye described later. For example, JP 59-152396 A, JP 61-151197 A, JP 63-41483 A, JP 63-41484 A, JP 2-249 A, and JP 2 -291, JP-A-3-27393, JP-A-3-12403, and JP-A-6-41170 can be appropriately selected and used.

  More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-pentafluorophen-1-yl (hereinafter also referred to as “T-1”), di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclo Pentadienyl-Ti-bis-2,4-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl Di-methylcyclopentadie Ru-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclo And pentadienyl) -bis (2,6-difluoro-3- (pyr-1-yl) phenyl) titanium (hereinafter also referred to as “T-2”).

  These titanocene compounds can be further subjected to various chemical modifications for improving the characteristics of the photosensitive layer. For example, bonding with sensitizing dyes, addition polymerizable unsaturated compounds and other radical generating parts, introduction of hydrophilic sites, compatibility improvement, introduction of substituents to suppress crystal precipitation, introduction of substituents to improve adhesion A method such as polymerization can be used.

  The use method of these titanocene compounds can be arbitrarily set as appropriate according to the performance design of the lithographic printing plate precursor as in the above-described addition polymerizable compound. For example, by using two or more kinds in combination, the compatibility with the photosensitive layer can be increased. A larger amount of the photopolymerization initiator such as the titanocene compound is usually more advantageous from the viewpoint of photosensitivity, and it is preferable that the amount of the photopolymerization initiator is 0.1% relative to 100 parts by mass of the non-volatile component of the photosensitive layer. Sufficient photosensitivity is obtained by using in 5-80 mass parts, Preferably it is 1-50 mass parts. On the other hand, when used under a white light such as yellow, it is preferable that the amount of titanocene used is small from the viewpoint of fogging by light near 500 nm, but the amount of titanocene used is 6 parts by mass in combination with a sensitizing dye. Thereafter, sufficient photosensitivity can be obtained even when the content is further reduced to 1.9 parts by mass or less, and further to 1.4 parts by mass or less.

As the thermal polymerization initiator used in the present invention for initiating and advancing the curing reaction of the addition polymerizable compound, a thermal decomposition type radical generator that decomposes by heat to generate radicals is useful. Such a radical generator is used in combination with the above-described infrared absorber, and when the infrared laser is irradiated, the infrared absorber generates heat and generates radicals by the heat. Recording is possible by combining these. It becomes.
Examples of the radical generator include onium salts, triazine compounds having a trihalomethyl group, peroxides, azo polymerization initiators, azide compounds, quinonediazides, oxime ester compounds, triaryl monoalkylborate compounds, etc. Or an oxime ester compound has high sensitivity and is preferable. Below, the onium salt which can be used suitably as a polymerization initiator in this invention is demonstrated. Preferred onium salts include iodonium salts, diazonium salts, and sulfonium salts. In the present invention, these onium salts function not as acid generators but as radical polymerization initiators. The onium salt suitably used in the present invention is an onium salt represented by the following general formulas (A) to (C).

In general formula (A), Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms, which may have a substituent. Preferred substituents when this aryl group has a substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or a group having 12 or less carbon atoms. An aryloxy group is mentioned. Z ¹¹⁻ represents a counter ion selected from the group consisting of a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, a carboxylate ion, and a sulfonate ion, preferably a perchlorate ion, Hexafluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

In the general formula (B), Ar ²¹ represents an aryl group having 20 or less carbon atoms which may have a substituent. Preferred examples of the substituent include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, an aryloxy group having 12 or less carbon atoms, and 12 or less carbon atoms. Examples thereof include an alkylamino group, a dialkylamino group having 12 or less carbon atoms, an arylamino group having 12 or less carbon atoms, or a diarylamino group having 12 or less carbon atoms. Z ^21- represents a counter ion having the same ^meaning as Z ^11- .

In the general formula (C), R ³¹ , R ³² and R ³³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. Z ^31- represents a counter ion having the same ^meaning as Z ^11- .

  In the present invention, specific examples of onium salts that can be suitably used as a polymerization initiator (radical generator) include those described in JP-A-2001-133696. In the present invention, onium salts represented by general formula (A) ([OI-1] to [OI-10]) and onium salts represented by general formula (B) ([ON] which can be suitably used in the present invention are shown below. -1] to [ON-5]), and specific examples of the onium salts ([OS-1] to [OS-7]) represented by the general formula (C), are not limited thereto. .

  The polymerization initiator used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. By making the absorption wavelength in the ultraviolet region in this way, the lithographic printing plate precursor can be handled under white light.

Other preferable polymerization initiators include specific aromatic sulfonium salts described in JP-A Nos. 2001-343742, 2002-006482, and 2002-148790. The typical compound is illustrated below.
Below, the typical compound of the other preferable polymerization initiator which can be applied to this invention is illustrated.

  Moreover, the oxime ester compound which can be used suitably as a polymerization initiator in this invention is demonstrated below. Preferred oxime ester compounds include compounds represented by the following general formula (D).

  In general formula (D), X represents a carbonyl group, a sulfone group, or a sulfoxide group, and Y represents a cyclic or chain alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, or an aryl group having 6 to 18 carbon atoms. An aryl group is an aromatic hydrocarbon compound such as a benzene ring, naphthalene ring, anthracene ring, phenanthrene group, pyrene group, triphenylene group, and a heterocyclic ring is a nitrogen atom, sulfur atom, oxygen atom For example, a pyrrole group, a furan group, a thiophene group, a selenophenone group, a pyrazole group, an imidazole group, a triazole group, a tetrazole group, an oxazole group, a thiazole group, an indole group, Benzofuran group, benzimidazole group, benzoxazole group, benzothiazole group, pyridine group Pyrimidine group, a pyrazine group, a triazine group, a quinoline group, a carbazole group, an acridine group, a phenoxazine, and a compound such as phenothiazine. These substituents represented by Y are halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, aldehyde group, alkyl group, thiol group, aryl group or alkenyl group, alkynyl group, ether group, ester group, urea Group, amino group, amide group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl group, imino group, halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, carbonyl group, urethane It can be substituted by a compound containing a group, an alkyl group, a thiol group, an aryl group, a phosphoroso group, a phospho group, or a carbonyl ether group.

  Z in the general formula (D) is synonymous with Y or is a nitrile group, a halogen atom, a hydrogen atom, or an amino group, and these Z compounds are halogen atoms, hydroxyl groups, nitrile groups, nitro groups, carboxyl groups, aldehyde groups. , Alkyl group, thiol group, aryl group or alkenyl group, alkynyl group, ether group, ester group, urea group, amino group, amide group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl Substitutable with compounds containing groups, imino groups, halogen atoms, hydroxyl groups, nitrile groups, nitro groups, carboxyl groups, carbonyl groups, urethane groups, alkyl groups, thiol groups, aryl groups, phosphoroso groups, phospho groups, carbonyl ether groups It is.

  W in the general formula (D) represents a divalent organic group, and represents a methylene group, a carbonyl group, a sulfoxide group, a sulfone group, or an imino group. The methylene group and the imino group are an alkyl group, an aryl group, an ester group, and a nitrile. It can be substituted by a compound containing a group, a carbonyl ether group, a sulfo group, a sulfo ether group, an ether group or the like. n represents an integer of 0 or 1.

V in the general formula (D) is a cyclic or chain alkyl group having 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, an aryl group having 6 to 18 carbon atoms, an alkoxy group, or an aryloxy group. Aromatic hydrocarbon compounds such as benzene ring, naphthalene ring, anthracene ring, phenanthrene group, pyrene group, triphenylene group, pyrrole group, furan group, thiophene group, selenophene group, pyrazole group, imidazole group, triazole group, tetrazole group, oxazole Group, thiazole group, indole group, benzofuran group, benzimidazole group, benzoxazole group, benzothiazole group, pyridine group, pyrimidine group, pyrazine group, triazine group, quinoline group, carbazole group, acridine group, phenoxazine, phenothiazine, etc. Including heteroatoms Aromatics. These V compounds are halogen atoms, hydroxyl groups, nitrile groups, nitro groups, carboxyl groups, aldehyde groups, alkyl groups, thiol groups, aryl groups or alkenyl groups, alkynyl groups, ether groups, ester groups, urea groups, amino groups, amides. Group, sulfide group, disulfide group, sulfoxide group, sulfo group, sulfone group, hydrazine group, carbonyl group, imino group, halogen atom, hydroxyl group, nitrile group, nitro group, carboxyl group, carbonyl group, urethane group, alkyl group, thiol It can be substituted by a compound containing a group, an aryl group, a phosphoroso group, a phospho group, or a carbonyl ether group.
V and Z may be bonded to each other to form a ring.

As the oxime ester compound represented by the general formula (D), from the viewpoint of sensitivity, X is carbonyl, Y is an aryl group or benzoyl group, Z group is an alkyl group or aryl group, W is a carbonyl group, V Is preferably an aryl group. More preferably, the aryl group of V has a thioether substituent.
Note that the structure of the N—O bond in the general formula (D) may be E-form or Z-form.

  Other oxime ester compounds that can be suitably used in the present invention include Progress in Organic Coatings, 13 (1985) 123-150; C. S Perkin II (1979) 1653-1660; Journal of Photopolymer Science and Technology (1995) 205-232; C. S Perkin II (1979) 156-162; JP-A 2000-66385; JP-A 2000-80068.

  Although the specific example of the oxime ester compound which can be used suitably for this invention is shown below, it is not limited to this.

  These polymerization initiators are from 0.1 to 50% by mass, preferably from 0.5 to 30% by mass, based on the total solid content constituting the photopolymerization layer, from the viewpoint of sensitivity and non-image area stains that occur during printing. %, Particularly preferably 1 to 20% by mass. 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.

<Sensitizing dye>
In the lithographic printing plate precursor according to the invention, the photopolymerization layer may contain a sensitizing dye. The sensitizing dye preferably has an absorption peak at 350 to 850 nm. Examples of such sensitizing dyes include spectral sensitizing dyes and the following dyes or pigments that absorb light from a light source and interact with a photopolymerization initiator.
Preferred spectral sensitizing dyes or dyes include polynuclear aromatics (eg, pyrene, perylene, triphenylene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, rose bengal), cyanines (eg, thianes). Carbocyanine, oxacarbocyanine), merocyanines (eg, merocyanine, carbomerocyanine), thiazines (eg, thionine, methylene blue, toluidine blue), acridines (eg, acridine orange, chloroflavin, acriflavine), phthalocyanines ( For example, phthalocyanine, metal phthalocyanine), porphyrins (for example, tetraphenylporphyrin, central metal-substituted porphyrin), chlorophylls (for example, chlorophyll, chlorophyllin, central gold) Substituted chlorophyll), metal complexes, anthraquinones (e.g., anthraquinone), squaryliums (e.g., squarylium), and the like.

  Examples of more preferable spectral sensitizing dyes or dyes include styryl dyes described in JP-B-37-13034, cationic dyes described in JP-A-62-143044, and quinoxalinium described in JP-B-59-24147. Salts, new methylene blue compounds described in JP-A No. 64-33104, anthraquinones described in JP-A No. 64-56767, benzoxanthene dyes described in JP-A No. 2-1714, JP-A No. 2-226148 and special Acridines described in the respective publications of Kaihei 2-226149, pyrylium salts described in Japanese Patent Publication No. 40-28499, cyanines described in Japanese Patent Publication No. 46-42363, benzofuran dyes described in Japanese Unexamined Patent Publication No. 2-63053, Conjugated ketone dyes described in JP-A-2-85858 and JP-A-2-216154 HirakiAkira 57-10605 described in JP-dye. Azocinnamylidene derivatives described in JP-B-2-30321, cyanine dyes described in JP-A-1-287105, JP-A-62-31844, JP-A-62-31848, JP-A-62-143043 Xanthene dyes described in Japanese Patent Publication Nos. JP-A Nos. 59-28325, merocyanine dyes described in JP-B No. 61-9621, and dyes described in JP-A No. 2-179433. A merocyanine dye described in JP-A-2-244050, a merocyanine dye described in JP-B-59-28326, a merocyanine dye described in JP-A-59-89803, a merocyanine dye described in JP-A-8-129257, and Examples thereof include benzopyran dyes described in JP-A-8-334897.

  As content of a sensitizing dye, Preferably it is 0.1-50 mass% with respect to the total solid which comprises a photopolymerization layer, More preferably, it is 0.5-30 mass%, Most preferably, it is 1-20 mass%. It is.

<Polymerizable compound>
The polymerizable compound that can be used in the photopolymerization layer of the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one ethylenically unsaturated bond, preferably 2 or more. It is chosen from the compound which has. Such a compound group is widely known in the said industrial field | area, and in this invention, these can be used without specifically limiting. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols.
As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, isocyanuric acid There are EO-modified triacrylate and the like.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include, for example, aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, and JP-A-59-5241. Those having an aromatic skeleton described in JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (a) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (a)
(However, R ₄ and R ₅ represent H or CH _3. )

  Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56-17654 Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Furthermore, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, JP-A-1-105238 Can obtain a photopolymerizable composition having an excellent photosensitive speed.

  Other examples include reacting polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191 and JP-B-52-30490. And polyfunctional acrylates and methacrylates such as epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid compounds described in JP-A-2-25493 are also included. be able to. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

  About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.

  From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. Further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.

  In addition, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components in the photopolymerization layer (for example, polymer compound, initiator, colorant, etc.) For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and an overcoat layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass with respect to the non-volatile component in the photopolymerization layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

<Microcapsule>
In the present invention, several modes can be used as a method for incorporating the above-mentioned photopolymerization layer constituents and other constituents described later into the photopolymerization layer. One is a molecular dispersion type photopolymerization layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or a part of the constituent components are encapsulated in microcapsules to form an image recording layer (photopolymerization layer). Is a microcapsule type image recording layer. Further, in the microcapsule type image recording layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule-type image recording layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule. In order to obtain better on-press developability, the photopolymerizable layer of the present invention is preferably a microcapsule type image recording layer.

  As a method for microencapsulating the above photopolymerization layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall 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 Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, 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. Further, a compound having a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the microcapsule wall.

  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 additives>
In the photopolymerization layer in the present invention, components other than those described above, for example, surfactants, colorants, print-out agents, polymerization inhibitors (thermal polymerization inhibitors), higher fatty acid derivatives, plasticizers, inorganic fine particles, low molecules A hydrophilic compound or the like can be contained. Such an additive can be added to the photopolymerization layer in a molecular dispersion state, but can be encapsulated in a microcapsule together with the polymerizable compound as necessary.

(Surfactant)
In the present invention, it is preferable to use a surfactant in the photopolymerization 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. Further, fluorine-based surfactants described in JP-A Nos. 62-170950, 62-226143, and 60-168144 are also preferable.

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 5% by mass with respect to the total solid content of the photopolymerization layer.

(Coloring agent)
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) 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 No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can 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. In addition, the ratio of 0.01-10 mass% is preferable with respect to the total solid of a photopolymerization layer.

(Bake-out agent)
In the photopolymerization 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 10% by mass with respect to the total solid content of the photopolymerization layer.

(Polymerization inhibitor)
A small amount of a thermal polymerization inhibitor is preferably added to the photopolymerization layer of the present invention in order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photopolymerization 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), and N-nitroso-N-phenylhydroxylamine aluminum salt.
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 photopolymerization layer.

(Higher fatty acid derivatives, etc.)
In order to prevent polymerization inhibition due to oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photopolymerization layer of the present invention, and the surface of the photopolymerization 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 photopolymerization layer.

(Plasticizer)
The photopolymerizable layer of the present invention may contain a plasticizer in order to improve 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, and the like as preferred.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photopolymerization layer.

(Inorganic fine particles)
The photopolymerization layer of the present invention may contain inorganic fine particles in order to improve the strength of the cured film in the image area and to improve the on-press developability of the non-image area.
Suitable inorganic fine particles include, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof. 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 μm 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 photopolymerization layer, sufficiently retains the film strength of the photopolymerization 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 40% by mass or less, and more preferably 30% by mass or less, based on the total solid content of the photopolymerization layer.

(Low molecular hydrophilic compound)
The photopolymerization layer of the present invention may contain a hydrophilic low molecular 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.

<Formation of photopolymerization layer>
The photopolymerizable 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 photopolymerization layer of the present invention can 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 repeating a plurality of coatings and dryings.

Moreover, although the photopolymerization layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film properties of the photopolymerization 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-like material. 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 these, 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.

  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 becomes easy to improve hydrophilicity and secure adhesion between the photopolymerization 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 (surface roughening treatment for dissolving the surface electrochemically), 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. Also, a transfer method in which the uneven shape is transferred with a roll provided with unevenness in the aluminum rolling step may 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 an electrolyte used for anodizing treatment of an 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 of anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, 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 / It is preferable that dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes. 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.

(Sealing treatment)
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. If necessary, the surface immersed in an aqueous solution containing a micropore enlargement treatment, sealing treatment, and hydrophilic compound described in JP-A Nos. 2001-253181 and 2001-322365 A hydrophilic treatment or the like can be appropriately selected and performed. Of course, the enlargement process and the sealing process are not limited to those described above, and any conventionally known methods can be performed.
For example, as the sealing treatment, in addition to the vapor sealing, single treatment with fluorinated zirconate, treatment with sodium fluoride, and vapor sealing with addition of lithium chloride are possible.

The sealing treatment used in the present invention is not particularly limited, and a conventionally known method can be used. Among them, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing with hot water are particularly preferable. Hole treatment is preferred. Each will be described below.
(Sealing treatment with an aqueous solution containing an inorganic fluorine compound)
As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably used.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluoride titanate, potassium fluoride titanate, fluorinated zirconate, fluorinated titanate, hexafluorosilicic acid, nickel fluoride, iron fluoride, phosphor fluoride, ammonium fluoride phosphate It is done. Among these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

  The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, it is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  It is preferable that the aqueous solution containing an inorganic fluorine compound further contains a phosphate compound. When the phosphate compound is contained, the hydrophilicity of the surface of the anodized film is improved, so that on-machine developability and stain resistance can be improved.

Suitable examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Among these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. Is preferred.

  The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving on-press developability and stain resistance. Further, in terms of solubility, it is preferably 20% by mass or less, and more preferably 5% by mass or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When the treatment is performed using the dipping method, the treatment time is preferably 1 second or longer, more preferably 3 seconds or longer, and preferably 100 seconds or shorter, and 20 seconds or shorter. More preferred.

(Sealing with water vapor)
Examples of the sealing treatment with water vapor include a method in which pressurized or normal pressure water vapor is brought into contact with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower. The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq). Further, the time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.

(Sealing treatment with hot water)
Examples of the sealing treatment with water vapor include a method in which an aluminum plate on which an anodized film is formed is immersed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt. The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower. Further, the time of immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, more preferably 100 seconds or shorter, and even more preferably 20 seconds or shorter.

(Hydrophilic treatment)
The hydrophilization treatment is described in 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 each 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 to the photopolymerization layer, good printing durability and good stain resistance can be obtained.

[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 an organic polymer compound described in JP-A-5-45885, an organometallic compound or an inorganic metal compound described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferable. 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 according to the present invention, if necessary, a protective layer is provided on the photopolymerization layer in order to prevent scratches in the photopolymerization layer, block oxygen, prevent ablation during high-illumination laser exposure, and the like. Can do.
In the present invention, the exposure is usually performed in the atmosphere, but the protective layer is a light 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 photopolymerization layer. It prevents the polymerization layer from being mixed, and prevents the image formation reaction from being inhibited 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 with the photopolymerization layer, and It is preferable that it can be easily removed in an 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. In general, PV
The higher the hydrolysis rate of A (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, unnecessary fogging during image exposure, image line thickening, and the like, it is preferable that the oxygen barrier property is not too 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 (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.
The thickness of the protective layer is suitably from 0.05 to 4 μm, particularly preferably from 0.1 to 2.5 μm.

  In addition, adhesion 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 a photopolymerizable layer that is oleophilic, the protective layer easily peels 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 photopolymerization 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 a photopolymerization layer. Any of these known techniques can be used in the present invention. 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.
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 infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

[Lithographic printing method]
As a light source for exposing the lithographic printing plate precursor according to the invention, a known light source can be used without limitation. The desirable wavelength of the light source is 300 nm to 1200 nm. Specifically, it is preferable to use various lasers as the light source, and among these, a semiconductor laser that emits infrared light having a wavelength of 760 nm to 1200 nm is preferably used.
The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.
In addition, as other exposure light rays for the lithographic printing plate precursor of the present invention, ultra high pressure, high pressure, medium pressure, low pressure mercury lamps, chemical lamps, carbon arc lamps, xenon lamps, metal halide lamps, various visible and ultraviolet laser lamps Fluorescent lamps, tungsten lamps, sunlight, etc. can also be used.

The lithographic printing method using the lithographic printing plate precursor according to the present invention is not particularly limited. For example, the lithographic printing plate precursor according to the present invention is imagewise exposed with a laser such as an infrared laser and then undergoes any development processing step. A method of printing by supplying oil-based ink and water-based component without any problem.
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 photopolymerized layer cured by forming an oil-based ink receiving portion having an oleophilic surface. On the other hand, in the unexposed area, the uncured photopolymerization layer is dissolved or dispersed and removed by the supplied aqueous component and / or oil-based ink, and a hydrophilic surface is exposed in the area. As a result, the aqueous component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the photopolymerized layer in the exposed area, and printing is started. Here, the aqueous component or oil-based ink may be supplied to the printing plate first, but the oil-based ink is first used in order to prevent the aqueous component from being contaminated by the unexposed photopolymerized layer. It is preferable to supply. As the aqueous component and oil-based ink, 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.

  Further, after the lithographic printing plate precursor of the present invention is imagewise exposed with a laser, a development treatment may be performed using a non-alkaline aqueous solution having a pH of 10 or less as a developer. As the non-alkaline aqueous solution that can be used here, for example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. The aqueous solution containing an aqueous solution or a surfactant (anionic, nonionic, cationic, etc.) is preferred. The pH of the developer is preferably from 2 to 10, more preferably from 3 to 9, and even more preferably from 5 to 9. .

The non-alkali aqueous solution that can be used as the developer may contain an organic acid, an inorganic acid, an inorganic salt, or the like.
Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content in the developer is preferably 0.01 to 5% by mass.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content in the developer is preferably 0.01 to 5% by mass.

  Examples of the anionic surfactant that can be used in the developer used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinates, linear alkylbenzenesulfonic acid salts, Branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamides Sodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfates Ester salt, fatty acid monoglyceride sulfate ester, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate Examples thereof include ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. Of these, dialkylsulfosuccinates, alkylsulfate esters and alkylnaphthalenesulfonates are particularly preferably used.

  The cationic surfactant that can be used in the developer 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.

Nonionic surfactants that can be used in the developer used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide Adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) Block copolymer, fatty acid ester of polyhydric alcohol glycerol, fatty acid ester of pentaerythritol, Bitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
These nonionic surfactants may be used alone or in admixture of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the developer of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more.
Furthermore, the ratio of the nonionic surfactant contained in the developer is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.
Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.
As the surfactant used in the developer of the present invention, a nonionic surfactant is particularly suitable from the viewpoint of foam suppression.

The developer used in the present invention may contain an organic solvent. Examples of the organic solvent that can be contained here include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons, and the like. (Toluene, xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and the following polar solvents.
Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol mono Ethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl Alcoa Etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl) Acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

  In the developer used in the present invention, as a water-soluble polymer compound, soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivative (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, Pullulan, polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. Can be contained.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10 mass% aqueous solution is in the range of 10 to 100 mPa / sec.

As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, more preferably from 0.5 to 10% by mass.

  In addition to the above, the developer used in the present invention may contain a preservative, a chelate compound, an antifoaming agent and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.

The development processing with a non-alkaline aqueous solution in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. As the automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs rubbing while conveying a lithographic printing plate precursor after image recording, Automatic processing for rubbing the lithographic printing plate precursor after image recording set on the cylinder described in the specifications of Japanese Patent No. 5148746, US Pat. No. 5,568,768 and British Patent No. 2297719 while rotating the cylinder Machine. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable. In the present invention, the lithographic printing plate after the rubbing treatment can be optionally washed with water, dried and desensitized.
Although the temperature of the developer can be used at any temperature, it is preferably 10 ° C to 50 ° C.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these.

1. Synthesis Example of Specific Copolymer Synthesis of (D-1) 250 g of N, N′-dimethylacetamide was placed in a 1000 ml three-necked flask equipped with a condenser and a stirrer and heated to 75 ° C. Under a nitrogen stream, 82 g of acrylamide 2,2-dimethylpropanesulfonic acid, 100 g of Phosmer PE (trade name: manufactured by Unichemical Co., Ltd.), 56 g of the following monomer (1), V-601 (trade name: manufactured by Wako Pure Chemical Industries) 2 A solution prepared by dissolving .50 g in 250 g of N, N′-dimethylacetamide was added dropwise over two and a half hours. The mixture was further reacted at 75 ° C. for 2 hours, returned to room temperature, and poured into ethyl acetate to precipitate a copolymer. This was decanted, washed, dried, dissolved in water to 10 mass%, and allowed to stand at room temperature for 1 day to give compound I-1. The mass average molecular weight measured by gel permeation chromatography (GPC) using polyacrylic acid as a standard substance was 40,000.
All the polymer compounds shown in the specific examples can be synthesized by the same method as in Synthesis Example 1.

2. Preparation of planographic printing plate precursor (1)
(1) Production of support After degreasing treatment at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution in order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm. The aluminum surface was grained with three bundle-planted nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed 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.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodic oxide coating of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by weight sulfuric acid (containing 0.5% by weight of aluminum ions) as an electrolytic solution, and then washed and dried. Body A. 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.

(2) Formation of undercoat layer The following undercoat liquids (1) to (5) were applied to the support A so that the dry coating amount was 10 mg / m ² , and the support was provided with an undercoat layer used in the following experiments. The body was made.
Undercoat liquid (1)
-Specific copolymer of the present invention described in Table 1 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

(3) Formation of photopolymerization layer [Examples 1 to 5]
On the support A-1 to A-5 prepared by applying the following undercoat liquids (1) to (5) to the support A, a photopolymerization layer coating liquid (1) having the following composition was bar-coated, and then 100 The plate was oven dried at 60 ° C. for 60 seconds to form a photopolymerization layer having a dry coating amount of 1.0 g / m ² to obtain a lithographic printing plate precursor.

The photopolymerization 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)
-0.162 g of the following polymer compound (1)
・ The following polymerization initiator (1) 0.100 g
・ The following infrared absorber (1) 0.020 g
・ Polymerizable monomer,
Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 0.385 g
-0.044 g of the following fluorosurfactant (1)
・ Methyl ethyl ketone (MEK) 1.091 g
1-methoxy-2-propanol (MFG) 8.609 g
Microcapsule liquid (1)
・ Microcapsule synthesized as follows (1) 2.640 g
・ Water 2.425g

Synthesis of microcapsule (1) As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (manufactured by Mitsui Takeda Chemical Co., Ltd., Takenate D-110N), 10 g of pentaerythritol triacrylate (manufactured by 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 Piionin 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.

[Comparative Examples 1-5]
Supports AX-1 to AX- having comparative undercoat layers in the same manner as described in Examples 1 to 5 except that the specific copolymer of the present invention is changed to X-1 to X-5 shown below. 5 was produced, and a photopolymerization layer was further formed to obtain a lithographic printing plate precursor for comparison.

3. Exposure and Printing Each planographic printing plate precursor obtained in the above Examples and Comparative Examples was exposed with a water-cooled 40 W infrared semiconductor laser-mounted Creo Trendsetter 3244VX under conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. . The exposure image includes a thin line chart. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Dampening water (EU-3 (Effect 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 supplying dampening water and ink, 100 sheets were printed at a printing speed of 6000 sheets per hour.
When the on-press development of the unexposed portion of the photopolymerization layer was completed on the printing press and the number of printing paper 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 stain on the non-image area was obtained within 100 sheets.

4). Evaluation In general, in the case of a negative lithographic printing plate precursor, when the exposure amount is small, the photopolymerization layer has a low degree of cure, and when the exposure amount is large, the degree of cure is high. If the photopolymerization layer has a too low degree of curing, the printing durability of the lithographic printing plate will be low, and the reproducibility of small dots and fine lines will be poor. On the other hand, when the degree of curing of the photopolymerization layer is high, the printing durability is increased, and the reproducibility of small dots and fine lines is improved.
In this example, as shown below, the negative lithographic printing plate precursor obtained as described above was evaluated for printing durability and fine line reproducibility under the same exposure amount conditions described above. It was used as an index of sensitivity. That is, it can be said that the sensitivity of the lithographic printing plate precursor is higher as the number of printed sheets in printing durability is higher and the fine line width in fine line reproducibility is thinner.
The evaluation methods for fine line reproducibility, printing durability, and storage stability are shown below. The evaluation results are shown in Table 3 together with the on-press developability results.

(1) Fine line reproducibility As described above, after 100 sheets were printed and it was confirmed that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were continuously printed. A thin line chart (10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 60, 80, 100 and 200 μm fine line exposed charts) of a total of 600 printed sheets with a 25X magnifier The fine line reproducibility was evaluated based on the fine line width that was observed and reproduced with ink without interruption.

(2) Printing durability As described above, after printing was performed in the evaluation of fine line reproducibility, printing was further continued. As the number of printed sheets was increased, the photopolymerization layer was gradually worn out and the ink receptivity was lowered, so that the ink density in the printing paper was lowered. Printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.

(3) Stain resistance Upon the printing durability evaluation described above, the prints of the 5,000th, 10,000th and 15,000th sheets are extracted, and the non-image area is visually checked for stains. confirmed. The case where no dirt was produced from 5,000 to 15,000 sheets was marked with ◯, the dirt after the 10,000th sheet was marked with △, and the dirt on the 5,000th sheet was marked with x.

(4) Storage stability 1
The unexposed lithographic printing plate precursor was stored at 45 ° C. and 75% humidity for 3 days, and the increase in the number of on-machine development before and after storage was examined. When the number of increase was less than 2, it was evaluated as ◯ when it was within 3 to 5, and when it was 6 or more, it was marked as x.

(5) Storage stability 2
The unexposed lithographic printing plate precursor was left under a fluorescent lamp (1000 lux) for 2 hours, and the increase in the number of on-machine development before and after being left was examined. When the number of increase was less than 2, it was evaluated as ◯ when it was within 3 to 5, and when it was 6 or more, it was marked as x.

  From Table 1, the lithographic printing plate precursor of the present invention satisfies all of fine line reproducibility (image quality), printing durability-stain resistance, on-press development, and storage stability.

5. Preparation (2) and evaluation of lithographic printing plate precursor [Examples 6 to 10 and Comparative Examples 6 to 10]
A lithographic printing plate precursor was prepared in the same manner as in the above Examples and Comparative Examples, except that the infrared absorbing agent (1) of the photosensitive solution (1) was changed to the sensitizing dye (1). These lithographic printing plate precursors were evaluated by 375 nm or 405 nm laser exposure shown in the following exposure method.

Exposure Method The planographic printing plate precursor was exposed using a 375 nm or 405 nm semiconductor laser under the conditions of an output of 2 mW, an outer drum with a peripheral length of 900 mm, a drum rotation speed of 800 rpm, and a resolution of 2400 dpi. One pixel drawing time is 1 microsecond (μs).

Printing method The lithographic printing plate precursor is attached to a cylinder of SOR-M manufactured by Heidelberg without developing the exposed exposed original plate, and dampening water (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 (manufactured by Dainippon Ink & Chemicals, Inc.) and after supplying dampening water and ink 100 sheets were printed at a printing speed of 6000 sheets per hour. Removal of the unexposed portion of the photopolymerized layer on the printing machine was completed, and a printed matter free from ink stains in the non-image portion was obtained.

  The results are shown in Table 2.

  From Table 2, the lithographic printing plate precursor of the present invention satisfies all of fine line reproducibility (image quality), printing durability-stain resistance, on-press development, and storage stability.

Claims (5)

A lithographic printing plate precursor having a laser-sensitive photopolymerization layer on a support and capable of forming an image without alkali development, wherein the other is located in the photopolymerization layer or between the support and the photopolymerization layer In the layer, (a1) a repeating unit having at least one radical chain crosslinkable group represented by the following general formula (A1), and (a2) a repeating unit having at least one functional group that interacts with the support surface A lithographic printing plate precursor comprising a copolymer having:
—C (R ₁ ) (R ₂ ) —C (R ₃ ) (L—X—H) — General Formula (A1)
(In the formula, X represents a group having a bond dissociation energy of XH at 25 ° C. of 95 kcal / mol [398 kJ / mol] or less. L is a divalent linking group, R _{1 to} R ₃ are hydrogen atoms, (It represents a hydrocarbon group or halogen atom which may have a substituent having 1 to 6 carbon atoms.)   2. The lithographic printing plate precursor as claimed in claim 1, wherein the polymer compound is a copolymer having (a3) a repeating unit having at least one hydrophilic group in the molecule.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the support is anodized aluminum and a chemical surface modification product thereof.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the photopolymerizable layer contains an infrared absorber.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the photopolymerizable layer contains microcapsules.