JP2010243517A - Lithographic printing plate precursor and method for manufacturing lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate precursor for providing a lithographic printing plate which is superior in the printing durability of an imaged part while satisfactorily maintaining the stain resistance of a non-imaged part, and to provide a method for manufacturing the lithographic printing plate. <P>SOLUTION: The lithographic printing plate precursor has, on a support, an image recording layer containing a polymerization initiator (i), a polymerizable compound (ii), and a binder polymer (iii), and a protection layer in this order, and an intermediate layer containing a polymer compound having at least one of acid groups selected from among sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups or their salts and a multivalent cation is provided between the support and the image recording layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate precursor and a method for producing a lithographic printing plate.

In general, a lithographic printing plate has a surface composed of an oleophilic image portion and a hydrophilic non-image portion. In lithographic printing, dampening water and oil-based ink are alternately applied to the surface of the lithographic printing plate, and the hydrophilic non-image area is dampened with the water-receiving area (ink non-reception area) by utilizing the property that water and oil repel each other. Part), and after allowing the ink to be received only in the oleophilic image part, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive layer (image recording layer) is provided on a hydrophilic support has been widely used. Normally, after exposing a lithographic printing plate precursor through an original image such as a lithographic film, the photosensitive layer to be an image portion is left, and other unnecessary photosensitive layers are dissolved with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by carrying out plate making by a method of exposing the surface of the hydrophilic support to form a non-image portion by removing it.

  In the conventional plate-making process of a lithographic printing plate precursor, a step of dissolving and removing unnecessary photosensitive layers with a developer or the like is necessary after exposure, but simplifies such additional wet processing. Is listed as one of the issues. As one of simplification, it is desired that development can be performed with an aqueous solution close to neutrality or simple 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 technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  From the background as described above, it is now more strongly desired than ever to adapt both the simplification of the plate making operation and the digitization.

  In a lithographic printing plate precursor having a photopolymerizable image recording layer on a support, it has a polymerization reactive group and a support adsorptive group between the support and the image recording layer in order to improve adhesion. It is known to provide an intermediate layer containing a compound (for example, Patent Documents 1 to 4). However, in all the known techniques, increasing the adhesion improves the printing durability of the image recording layer of the exposed portion (image portion), but deteriorates the stain resistance of the non-exposed portion (non-image portion). Therefore, it is difficult to achieve both the printing durability of the exposed area and the stain resistance of the non-exposed area.

  It is also known to provide an intermediate layer containing a compound having a highly hydrophilic functional group in order to improve the stain resistance of non-image areas (for example, Patent Document 5). However, in the conventionally known technique, when the hydrophilicity of the functional group is increased, the hydrophilicity of the intermediate layer is increased, and the adhesiveness to the image recording layer (image portion) having high hydrophobicity is decreased. There was a problem that the printing durability of the ink deteriorated.

Japanese Patent Laid-Open No. 7-159983 JP-A-9-269593 JP 2000-235254 A JP 2008-77078 A JP 2006-239867 A

  An object of the present invention is to provide a lithographic printing plate precursor and a method for producing a lithographic printing plate that can provide a lithographic printing plate excellent in printing durability of an image area while maintaining good stain resistance of a non-image area. is there.

  The above object has been achieved by providing an intermediate layer containing a polymer compound having an anionic functional group and a polyvalent cation between the support and the image recording layer. The present invention is as follows.

(1) A lithographic printing plate precursor having, on a support, an image recording layer containing (i) a polymerization initiator, (ii) a polymerizable compound, and (iii) a binder polymer, and a protective layer in this order, An intermediate layer containing a polymer compound having at least one acid group selected from a sulfonic acid group, a carboxylic acid group and a phosphoric acid group or a salt thereof and a polyvalent cation between the support and the image recording layer A lithographic printing plate precursor comprising:
(2) The lithographic printing plate precursor as described in (1) above, wherein the acid group of the polymer compound is a carboxylic acid group or a sulfonic acid group.
(3) The lithographic printing plate precursor as described in (1) or (2) above, wherein the polymer compound further has a support adsorptive group.
(4) The lithographic printing plate as described in (3) above, wherein the support-adsorbing group is any one of an onium base, a phosphoric acid group, a phosphonic acid group, a boric acid group, and a β-diketone group. Original edition.
(5) The lithographic printing plate precursor as described in (4) above, wherein the support-adsorbing group is a phosphate group.
(6) The lithographic printing plate precursor as described in any one of (1) to (5) above, wherein the polymer compound further has an ethylenically unsaturated bond group.
(7) The lithographic printing plate precursor as described in any one of (1) to (6) above, wherein the polyvalent cation is a divalent or higher alkaline earth metal ion or transition metal ion .
(8) The lithographic printing plate precursor as described in (7) above, wherein the polyvalent cation is calcium ion, magnesium ion, copper (II) ion, aluminum ion or iron (II) ion.
(9) The lithographic printing according to any one of (1) to (8), wherein the intermediate layer is formed by applying a coating solution containing the polymer compound and a polyvalent cation. Version original edition.
(10) Any of the above (1) to (8), wherein the intermediate layer is formed by applying a coating solution containing the polymer compound and then applying a coating solution containing the polyvalent cation. The lithographic printing plate precursor as described in 1 above.
(11) Any of the above (1) to (8), wherein the intermediate layer is coated with a treatment liquid containing the polyvalent cation after the application liquid containing the polymer compound is applied. The lithographic printing plate precursor as described in 1 above.
(12) Any of the above (1) to (8), wherein the intermediate layer is treated with a treatment liquid containing the polymer compound and then coated with a coating liquid containing the polyvalent cation. The lithographic printing plate precursor as described in 1 above.
(13) Any of the above (1) to (8), wherein the intermediate layer is treated with a treatment liquid containing the polyvalent cation after being treated with the treatment liquid containing the polymer compound. The lithographic printing plate precursor as described in 1 above.
(14) The lithographic printing according to any one of (1) to (8), wherein the intermediate layer is treated with a treatment liquid containing the polymer compound and a polyvalent cation. Version original edition.
(15) A method for preparing a lithographic printing plate, comprising treating the lithographic printing plate precursor according to any one of (1) to (14) with a developer having a pH of 2 to 11.
(16) The method for preparing a lithographic printing plate as described in (15) above, wherein the developer contains carbonate ions and hydrogen carbonate ions.

  According to the present invention, there is provided a lithographic printing plate precursor capable of providing a lithographic printing plate excellent in printing durability in an image area while maintaining good stain resistance in a non-image area, and a method for producing the lithographic printing plate. Can do.

It is explanatory drawing which shows the structure of an automatic developing processor.

[Lithographic printing plate precursor]
First, a planographic printing plate precursor according to the present invention will be described. The lithographic printing plate precursor according to the invention has an intermediate layer between the image recording layer and the support.

<Intermediate layer>
The intermediate layer according to the present invention includes a polymer compound having at least one acid group selected from a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group or a salt thereof (hereinafter also referred to as a specific polymer compound for the intermediate layer) and many And a valent cation.

  The specific polymer compound for the intermediate layer is not particularly limited as long as it is a polymer compound having at least one acid group selected from a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group or a salt thereof. Among the acid groups, a sulfonic acid group or a carboxylic acid group is preferable in terms of electrostatic interaction with a polyvalent cation.

The specific polymer compound for the intermediate layer preferably has adsorptivity to the support surface. The presence or absence of adsorptivity to the support surface can be determined by the following method, for example.
A coating solution is prepared by dissolving the specific polymer compound for the intermediate layer (test compound) in a readily soluble solvent, and the coating solution is applied onto the support so that the coating amount after drying is 30 mg / m ^2. dry. The substrate coated with the test compound is sufficiently washed with a readily soluble solvent, and then the residual amount of the test compound that has not been removed by washing is measured to calculate the amount of adsorption of the substrate. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining test compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The test compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, or liquid chromatography measurement. A compound having a support adsorptivity is a compound that remains in an amount of 0.1 mg / m ² or more even after the washing treatment as described above.

  As the specific polymer compound for the intermediate layer, a polymer compound having a repeating unit represented by the following formula (A1) is preferable.

In formula (A1), R _{1 to} R ₃ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. L represents a single bond or a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. W is -COOM _1, represents a _-SO 3 _{M 1} or _{-OPO (OM 1) (OM 2} ). M ₁ and M ₂ each independently represents a hydrogen atom, a metal atom or an ammonium group.

Specific examples of L composed of combinations are given below. In the following examples, the left side is bonded to the main chain.
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-O-divalent aliphatic group -CO-O-divalent aliphatic group -O-CO-
L9: -CO-O-divalent aliphatic group -O-CO-divalent aliphatic group -O-CO-
L10: -CO-O-divalent aromatic group -CO-O-divalent aliphatic group -O-CO-
L11: -CO-O-divalent aromatic group -O-CO-divalent aliphatic group -O-CO-
L12: -CO-O-divalent aliphatic group -CO-O-divalent aromatic group -O-CO-
L13: -CO-O-divalent aliphatic group -O-CO-divalent aromatic group -O-CO-
L14: -CO-O-divalent aromatic group -CO-O-divalent aromatic group -O-CO-
L15: -CO-O-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-

Examples of the divalent aliphatic group include an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, a substituted alkynylene group, and a polyalkyleneoxy group. Of these, an alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and a substituted alkylene group are more preferred.
The divalent aliphatic group is preferably a chain structure rather than a cyclic structure, and more preferably a straight chain structure than a branched chain structure.
The number of carbon atoms of 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. Preferably, it is 1-8.
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, monoarylamino group, diarylamino group and the like.

Examples of the divalent aromatic group include an arylene group and a substituted arylene group. Preferable are a phenylene group, a substituted phenylene group, a naphthylene group, and a 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.

  The specific polymer compound for the intermediate layer preferably further has a support adsorbing group. Examples of the support adsorptive group include a group capable of forming a bond such as a covalent bond, an ionic bond, and a hydrogen bond with a metal, metal oxide, or hydroxyl group present on the support, polar interaction, van der Waals. Examples include groups capable of interaction such as interaction. Specific examples of the support-adsorptive group are listed below.

(Wherein 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 an ammonium group) And X ⁻ represents a counter anion.)

As the support adsorbing group, an onium base such as an ammonium group or a pyridinium group, or a β-diketone group such as a phosphoric acid group (—OPO ₃ H ₂ ), a phosphonic acid group, a boric acid group, or an acetylacetone group is preferable. In particular, a phosphate group is preferable. In the present invention, the phosphate group is a group having a function of interacting with a polyvalent cation as described above, but also has a function as a support-adsorbing group.

  As a specific high molecular compound for intermediate | middle layers which has a support body adsorptive group, the high molecular compound which has a repeating unit represented by a following formula (A2) is preferable, for example.

Wherein _(A2), R 1 ~R ₃ and L have the same meanings as _R 1 to R ₃ and L in each of the formulas (A1). Q represents a support adsorptive group.

Specific examples of L composed of combinations include the following in addition to the specific examples of L in the formula (A1). In the following examples, the left side is bonded to the main chain.
L18: —CO—NH—
L19: -CO-O-
L20: -Divalent aromatic group-

  The specific polymer compound for an intermediate layer preferably further has an ethylenically unsaturated bond group.

  As the specific polymer compound for an intermediate layer having an ethylenically unsaturated bond group, for example, a polymer compound having a repeating unit represented by the following formula (A3) is preferable.

Wherein _(A3), R 1 ~R ₃ is the same meaning as _R 1 to R ₃ in Formula (A1). L has the same meaning as the divalent linking group represented by L in the formula (A1). R _{4 to} R ₆ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a halogen atom, an acyl group, or an acyloxy group. Alternatively, R ₄ and R ₅ or R ₅ and R ₆ may be bonded to each other to form a ring.

As the specific polymer compound for the intermediate layer, a polymer compound having a repeating unit represented by the formula (A1) is preferable, and represented by the formula (A2) in addition to the repeating unit represented by the formula (A1). The polymer compound having a repeating unit or a repeating unit represented by the formula (A3) is more preferable. In addition to the repeating unit represented by the formula (A1), the repeating unit represented by the formula (A2) and the formula (A3) The polymer compound having a repeating unit represented by
In the specific polymer compound for an intermediate layer, the monomer corresponding to the repeating unit represented by the formula (A1) is preferably 5 to 100 mol%, more preferably 30 to 90 mol%, more preferably 50 to 85, based on all polymerization monomers. More preferred is mol%. The monomer corresponding to the repeating unit represented by the formula (A2) is preferably from 5 to 80 mol%, more preferably from 10 to 50 mol%, based on the total polymerization monomers. The monomer corresponding to the repeating unit represented by the formula (A3) is preferably from 5 to 80 mol%, more preferably from 10 to 50 mol%, based on the total polymerization monomers.
The mass average molecular weight of the specific polymer compound for intermediate layer is preferably 10,000 to 500,000, and more preferably 50,000 to 200,000.

  Specific examples of the specific polymer compound for intermediate layer used in the present invention are shown below, but are not limited thereto.

  The polyvalent cation contained in the intermediate layer of the present invention is a divalent or higher cation. For example, an alkaline earth metal ion or a transition metal ion can be used. In particular, calcium ion, magnesium ion, copper (II) ion, aluminum ion, and iron (II) ion are preferable.

  The intermediate layer can be formed by applying the specific polymer compound for the intermediate layer and the polyvalent cation separately or together on the support. That is, a method of coating and drying water or a solution containing a specific polymer compound for intermediate layer and / or a polyvalent cation in an organic solvent such as methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof on a support, and support Is treated with water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof and a solution containing the specific compound for the intermediate layer and / or a polyvalent cation, or a combination thereof, or a combination thereof. . In order to treat the support with a solution containing the intermediate layer specific compound and / or polyvalent cation, a method of immersing the support in the solution is preferably used. After the treatment with the solution, the support may be washed with water or the like as necessary. The specific polymer compound for the intermediate layer is preferably provided on the support before or simultaneously with the polyvalent cation.

  Specifically, (a) a method of applying a coating solution containing a polymer compound and a cation, (b) a method of applying a coating solution containing a cation after applying a coating solution containing a polymer compound, (C) A method in which a coating solution containing a polymer compound is applied and then treated with a treatment solution containing a cation. (D) After a treatment with a treatment solution containing a polymer compound, a coating solution containing a cation is applied. Preferably used are a method, (e) a treatment with a treatment liquid containing a polymer compound, and then a treatment with a treatment liquid containing a cation, and (f) a treatment with a treatment liquid containing a polymer compound and a cation. It is done.

  In the method using a coating solution, a coating solution having a concentration of each component of about 0.005 to 10% by mass can be applied by various known methods. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. In the method using the treatment liquid, the concentration of each component is about 0.01 to 20% by mass, preferably about 0.05 to 5% by mass, and the treatment liquid temperature is about 20 to 90 ° C., preferably 25 to 25%. It is about 50 ° C., and the treatment time is about 0.1 second to 20 minutes, preferably about 2 seconds to 1 minute.

The coating amount of the intermediate layer for a specific polymer compound, as a dry mass, preferably from 1 to 100 mg / m ^2, more preferably 1.0 to 50 mg / m ^2, more preferably 5.0~20mg / m ^2. The coating amount of the multivalent cations, as dry weight, preferably from 0.1 to 10 mg / m ^2, more preferably ^{0.5~5.0mg / m 2, 1.0~3.0mg / m} 2 is Further preferred.

  If necessary, the intermediate layer can contain a surfactant for improving the coated surface. For example, compounds described in paragraph numbers [0161]-[0201] of JP-A-2007-206217 are used.

<Image recording layer>
The image recording layer (hereinafter also referred to as photosensitive layer) of the lithographic printing plate precursor according to the invention contains (i) a polymerization initiator, (ii) a polymerizable compound, and (iii) a binder polymer.

(Polymerization initiator)
As the polymerization initiator (hereinafter also referred to as initiator compound) contained in the image recording layer in the present invention, a radical polymerization initiator is preferably used.

  As the initiator compound in the present invention, those known among those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, Examples include hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salts, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable.

  Examples of the hexaarylbiimidazole compound include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, such as 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'. -Tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) -4, 4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2,2'- Bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5'-tetrafe Rubiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethylphenyl) -4,4' , 5,5'-tetraphenylbiimidazole and the like. The hexaarylbiimidazole compound is particularly preferably used together with a sensitizing dye having a maximum absorption at 300 to 450 nm.

  The onium salts preferably used in the present invention are sulfonium salts, iodonium salts, and diazonium salts. In particular, diaryliodonium salts and triarylsulfonium salts are preferably used. The onium salt is particularly preferably used with an infrared absorber having a maximum absorption at 750 to 1400 nm.

  As other polymerization initiators, polymerization initiators described in paragraph numbers [0071] to [0129] of JP-A-2007-206217 can be preferably used.

  The polymerization initiator is preferably used alone or in combination of two or more. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, and still more preferably 1.0 to 10% by mass with respect to the total solid content of the photosensitive layer.

(Polymerizable compound)
The polymerizable compound used for the photosensitive layer in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is a compound having at least one terminal ethylenically unsaturated bond, preferably two or more. To be elected. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group and the like with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration-condensation reaction product with carboxylic acid is also preferably used. Also, addition reaction products of unsaturated carboxylic acid esters or amides having electrophilic substituents such as isocyanate groups and epoxy groups with monofunctional or polyfunctional alcohols, amines and thiols, as well as halogen groups and tosyloxy A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. 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 the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bisacrylamide, methylene bismethacrylamide, 1,6-hexamethylene bisacrylamide, 1,6-hexamethylene bismethacrylamide, Examples include diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

  Further, 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, 2 molecules per molecule described in JP-B-48-41708. A vinyl urethane compound 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 one or more isocyanate groups Is mentioned.

_{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, and 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.

  Details of the method of use, such as the structure of the polymerizable compound, whether it is used alone or in combination, and the amount added, can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. The polymerizable compound is preferably used in the range of 5 to 75% by mass, more preferably 25 to 70% by mass, and particularly preferably 30 to 60% by mass with respect to the total solid content of the photosensitive layer.

(Binder polymer)
The photosensitive layer in the present invention contains a binder polymer. As the binder polymer, one that can carry the photosensitive layer component on a support and can be removed by a developer is used. As the binder polymer, (meth) acrylic polymer, polyurethane resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, epoxy resin and the like are used. In particular, (meth) acrylic polymers and polyurethane resins are preferably used.

  In the present invention, “(meth) acrylic polymer” means (meth) acrylic acid, (meth) acrylic acid ester (alkyl ester, aryl ester, allyl ester, etc.), (meth) acrylamide and (meth) acrylamide derivatives. It refers to a copolymer having a (meth) acrylic acid derivative such as “Polyurethane resin” refers to a polymer produced by a condensation reaction of a compound having two or more isocyanate groups and a compound having two or more hydroxyl groups. “Polyvinyl butyral resin” refers to a polymer synthesized by reacting polyvinyl alcohol obtained by saponifying a part or all of polyvinyl acetate and butyraldehyde under an acidic condition (acetalization reaction). Further, a polymer having an acid group or the like introduced by a method of reacting a compound having a remaining hydroxy group and an acid group or the like is also included.

  A suitable example of the binder polymer in the present invention includes a copolymer having a repeating unit containing an acid group. Examples of the acid group include a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid group, and a sulfonamide group. A carboxylic acid group is particularly preferable, and a repeating unit represented by the following general formula (I) is used. The polymer having is preferably used.

In general formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a single bond or an n + 1 valent linking group. A represents an oxygen atom or —NR ³ —, and R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. n represents an integer of 1 to 5.

The linking group represented by R ² in the general formula (I) is composed of a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, and the number of atoms is preferably 1 to 80. Specific examples include alkylene, substituted alkylene, arylene, substituted arylene, and the like, and a structure in which a plurality of these divalent groups are linked by an amide bond or an ester bond may be used. R ² is preferably a single bond, alkylene or substituted alkylene, particularly preferably a single bond, alkylene having 1 to 5 carbons or substituted alkylene having 1 to 5 carbons, single bond or carbon number 1 It is most preferable that it is -3 alkylene and a C1-C3 substituted alkylene.
Examples of the substituent include a monovalent non-metallic atomic group excluding a hydrogen atom, a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, An acyl group, a carboxyl group and its conjugate base group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an aryl group, an alkenyl group, an alkynyl group and the like can be mentioned.

R ³ is preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, particularly preferably a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and most preferably a hydrogen atom or a methyl group. n is preferably 1 to 3, particularly preferably 1 or 2, and most preferably 1.

The proportion of the copolymer component having a carboxylic acid group in the total copolymer components of the binder polymer is preferably 1 to 70 mol% from the viewpoint of developability. In consideration of compatibility between developability and printing durability, 1 to 50 mol% is more preferable, and 1 to 30 mol% is particularly preferable.
The binder polymer used in the present invention preferably further has a crosslinkable group. Here, the crosslinkable group is a group that crosslinks the binder polymer in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, etc. are mentioned, for example. Of these, an ethylenically unsaturated bond group is preferable. As the ethylenically unsaturated bond group, a styryl group, a (meth) acryloyl group, and an allyl group are preferable.

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

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodometric titration) is preferably 0.01 to 10.0 mmol, more preferably 0.05, per 1 g of the binder polymer. -5.0 mmol, most preferably 0.1-2.0 mmol.

  The binder polymer used in the present invention may have a polymer unit of an alkyl (meth) acrylate or an aralkyl ester in addition to the polymer unit having an acid group and a polymer unit having a crosslinkable group. The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group. Examples of (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

The binder polymer preferably has a mass average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.
A binder polymer may be used independently or may be used in mixture of 2 or more types. The content of the binder polymer is preferably from 5 to 75 mass%, more preferably from 10 to 70 mass%, more preferably from 10 to 70 mass%, based on the total solid content of the photosensitive layer, from the viewpoint of good image area strength and image formability. 60 mass% is still more preferable.
Further, the total content of the polymerizable compound and the binder polymer is preferably 80% by mass or less based on the total solid content of the photosensitive layer. If it exceeds 80% by mass, the sensitivity and developability may be lowered. More preferably, it is 35-75 mass%.

(Sensitizing dye)
The photosensitive layer in the present invention preferably contains a sensitizing dye. The sensitizing dye is not particularly limited as long as it absorbs light at the time of image exposure to be in an excited state, supplies energy to the polymerization initiator by electron transfer, energy transfer or heat generation, and improves the polymerization start function. Can be used. In particular, a sensitizing dye having a maximum absorption at 300 to 450 nm or 750 to 1400 nm is preferably used.

  Examples of the sensitizing dye having the maximum absorption in the wavelength region of 300 to 450 nm include merocyanines, benzopyrans, coumarins, aromatic ketones, anthracenes and the like.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 300 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (IX).

In General Formula (IX), A represents an aromatic ring group or a heterocyclic group which may have a substituent, and X represents an oxygen atom, a sulfur atom, or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent nonmetallic atomic group, and A and R ₁ or R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. It may be formed.

In the general formula (IX), R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, A substituted or unsubstituted aryl group, a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, and a halogen atom are represented.

A represents an aromatic ring group or a heterocyclic group which may have a substituent, and the aromatic ring group or heterocyclic group which may have a substituent is represented by the above R ₁ , R ₂ and R ₃ This is the same as the aryl group or aromatic heterocyclic residue.

  As such a sensitizing dye, compounds described in paragraph numbers [0047] to [0053] of JP-A-2007-58170 are preferably used.

  JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, JP 2007-316582, JP 2007-328243. The sensitizing dyes described in 1) can also be preferably used.

  As a sensitizing dye (hereinafter also referred to as an infrared absorber) having a maximum absorption at 750 to 1400 nm that is suitably used in the present invention, a dye or a pigment is preferably used.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Among these dyes, cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes are preferable. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ₂ , X ² -L ¹ or the following group. Here, X ² represents an oxygen atom, a nitrogen atom or a sulfur atom, and L ¹ represents an aromatic ring having a hydrocarbon group having 1 to 12 carbon atoms and a hetero atom (N, S, O, halogen atom, Se). Group, a C1-C12 hydrocarbon group containing a hetero atom. X _a ^- is Z _a to be described later ^- which is synonymous with. R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, or a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive 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 6 It is particularly preferable that a member 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. Preferable aromatic hydrocarbon groups include a benzene ring group and a naphthalene ring group. 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. Za ⁻ represents a counter anion. However, when the cyanine dye represented by formula (a) has an anionic substituent in its structure and does not require charge neutralization, Za ^- is not necessary. Za ⁻ is preferably a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion or a sulfonate ion, particularly preferably a perchlorate ion or hexafluoro, from the storage stability of the photosensitive layer coating solution. Phosphate ion or aryl sulfonate ion.

  Specific examples of the cyanine dye represented by the general formula (a) include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969.

  Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057.

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

  The addition amount of the sensitizing dye is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photosensitive layer. Part.

(Other photosensitive layer components)
The photosensitive layer preferably further contains a chain transfer agent. As the chain transfer agent, for example, a compound having SH, PH, SiH, or GeH in the molecule is used. The chain transfer agent can generate a radical by donating hydrogen to a low-activity radical species or by deprotonation after being oxidized.
In particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) are chain transfer agents for the photosensitive layer. Can be preferably used. Specific examples of the thiol compound are described, for example, in paragraphs [0212] to [0216] of JP-A-2008-276155.

  The photosensitive layer can further contain various additives as required. Additives include surfactants for promoting developability and improving the surface of the coating, microcapsules for achieving both developability and printing durability, and improving the developability and dispersion stability of microcapsules. Hydrophilic polymer, colorant and print-out agent for visually recognizing image areas and non-image areas, polymerization inhibitor for preventing unnecessary thermal polymerization of radically polymerizable compounds during production or storage of the photosensitive layer, oxygen Higher fatty acid derivatives to prevent polymerization inhibition due to polymerization, inorganic fine particles to improve the cured film strength of the image area, hydrophilic low molecular weight compounds to improve developability, co-sensitizers to improve sensitivity, plasticity improvement For example, a plasticizer. Any of these compounds can be used, for example, compounds described in paragraph numbers [0161] to [0215] of JP-A-2007-206217.

(Formation of photosensitive layer)
The photosensitive layer is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Examples of the solvent include, but are not limited to, methyl ethyl ketone, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, and γ-butyllactone. It is not something. A solvent is used individually or in mixture. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

The coating amount (solid content) of the photosensitive layer on the support obtained after coating and drying is preferably from 0.3 to 3.0 g / m ² . Various methods can be used as the coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is provided on the photosensitive layer in order to block oxygen intrusion and diffusion that hinders the polymerization reaction during exposure. It is preferable to use a water-soluble polymer compound having relatively excellent crystallinity for the protective layer. Specifically, when polyvinyl alcohol is used as a main component, good results are obtained in terms of basic characteristics such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, ether or acetal as long as it contains an unsubstituted vinyl alcohol unit for having the necessary oxygen barrier properties and water solubility. Moreover, one part may have another copolymerization component. Polyvinyl alcohol is obtained by hydrolyzing polyvinyl acetate. Specific examples of polyvinyl alcohol include those having a hydrolysis degree of 71 to 100 mol% and a number of polymerization repeating units of 300 to 2400. Specifically, 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, L-8 and the like. Polyvinyl alcohol can be used alone or in combination. The content rate in the protective layer of polyvinyl alcohol becomes like this. Preferably it is 20-95 mass%, More preferably, it is 30-90 mass%.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. In particular, acid-modified polyvinyl alcohol having a carboxylic acid group or a sulfonic acid group is preferably used. As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoints of oxygen barrier properties, development removability, and the like. The content rate in a protective layer is 3.5-80 mass%, Preferably it is 10-60 mass%, More preferably, it is 15-30 mass%.

  In the protective layer, glycerin, dipropylene glycol or the like can be added by several mass% with respect to the binder to give flexibility. In addition, anionic surfactants such as sodium alkyl sulfate and sodium alkyl sulfonate, alkyl An amphoteric surfactant such as an aminocarboxylate and an alkylaminodicarboxylate or a nonionic surfactant such as polyoxyethylene alkylphenyl ether can be added in an amount of several mass% based on the binder.

  Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection. Among inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful.

The coating amount of the protective layer is a coating amount after drying is preferably 0.05 to 10 g / m ^2, when the protective layer contains the inorganic stratiform compound, more preferably 0.1-5 g / m ^2, the inorganic When not containing a layered compound, 0.5-5 g / m < ² > is more preferable.

<Support>
The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. In particular, an aluminum plate is preferable. Prior to using the aluminum plate, it is preferable to perform surface treatment such as roughening treatment or anodizing treatment. 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 electrochemically dissolving the surface), chemical surface treatment, etc. Roughening treatment (roughening treatment that selectively dissolves the surface chemically) can be mentioned. As these treatments, methods described in paragraph numbers [0241] to [0245] of JP-A-2007-206217 can be preferably used.

  The center line average roughness of the support is preferably from 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained. The color density of the support is preferably from 0.15 to 0.65 in terms of the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained. The thickness of the support is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and still more preferably 0.2 to 0.3 mm.

(Hydrophilic treatment of support surface>
In the lithographic printing plate precursor according to the invention, it is preferable to further perform a hydrophilic treatment on the surface of the support in order to improve the hydrophilicity of the non-image area and prevent printing stains.

  Examples of the hydrophilization treatment of the support surface include an alkali metal silicate treatment method in which the support is immersed or electrolyzed in an aqueous solution of sodium silicate, a treatment method with potassium fluorinated zirconate, a treatment method with polyvinylphosphonic acid, etc. A method of immersing in an aqueous polyvinylphosphonic acid solution is preferably used.

<Back coat layer>
In the lithographic printing plate precursor according to the invention, a backcoat layer can be provided on the back surface of the support, if necessary. As the back coat layer, for example, an organic polymer compound described in JP-A-5-45885, an organometallic compound or an inorganic metal compound described in JP-A-6-35174 is hydrolyzed and polycondensed. A coating layer made of the obtained metal oxide 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.

[Preparation method of planographic printing plate]
A lithographic printing plate is produced by subjecting the lithographic printing plate precursor according to the present invention to image development and development.

<Image exposure>
The lithographic printing plate precursor is imagewise exposed by laser exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser beam scanning by digital data.
The wavelength of the light source is preferably 300 nm to 450 nm or 750 nm to 1400 nm. In the case of 300 nm to 450 nm, a lithographic printing plate precursor having a sensitizing dye having an absorption maximum in this region in the photosensitive layer is used, and in the case of 750 nm to 1400 nm, infrared absorption which is a sensitizing dye having absorption in this region. A lithographic printing plate precursor containing an agent is used. As the light source of 300 nm to 450 nm, a semiconductor laser is suitable. As the light source of 750 nm to 1400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

<Development processing>
As the development treatment, generally (1) a method of developing with an alkaline developer (pH is higher than 11), (2) a method of developing with a developer having a pH of 2 to 11, (3) on a printing press, A method of developing while supplying dampening water and ink (on-press development) can be mentioned.
In the development step using the alkaline developer (1), the protective layer is removed by the pre-water washing step, then alkali development is performed, the alkali is washed and removed by the post-water washing step, the gum solution treatment is performed, and the drying step is performed. It is necessary to dry. In the method (2) of developing with a developer having a pH of 2 to 11, development and gum solution treatment can be simultaneously performed by incorporating a surfactant or a water-soluble polymer compound in the developer. Therefore, the post-water washing step is not particularly required, and the drying step can be performed after the development and gum solution treatment with one solution. Further, the pre-water washing step is not particularly required, and the protective layer can be removed simultaneously with development and gum solution treatment. After development and gumming, it is preferable to dry after removing the excess developer using a squeeze roller. In addition, the development method (2) has the advantage of being freed from dealing with development residue derived from the protective layer / photosensitive layer generated during printing in the case of on-press development of (3).

In the present invention, a method of developing with a developer having a pH of 2 to 11 is preferably used.
That is, in the method for preparing a lithographic printing plate of the present invention, the protective layer and the photosensitive layer in the non-exposed area can be removed together with a developer having a pH of 2 to 11, and then immediately set in a printing press for printing. The development of the lithographic printing plate precursor according to the invention is carried out according to a conventional method at a temperature of 0 to 60 ° C., preferably about 15 to 40 ° C. It is carried out by a method, a method of spraying a developer by spraying and rubbing with a brush.

  The development processing in the present invention can be preferably carried out by an automatic development processor equipped with a developer supply means and a rubbing member. An automatic developing processor using a rotating brush roll as the rubbing member is particularly preferable. Furthermore, it is preferable that the automatic developing processor is provided with a means for removing excess developer such as a squeeze roller and a drying means such as a warm air device after the development processing means.

  The developer used in the present invention is preferably an aqueous solution containing water as a main component (containing 60% by mass or more of water), and particularly contains a surfactant (anionic, nonionic, cationic, zwitterionic, etc.). An aqueous solution containing a water-soluble polymer compound is preferable. An aqueous solution containing both a surfactant and a water-soluble polymer compound is also preferred. The pH of the developer is preferably 2 to 11, more preferably 5 to 10.7, further preferably 6 to 10.5, and most preferably 7.5 to 10.3.

  The anionic surfactant used in the developing solution is not particularly limited, and fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinates, linear alkylbenzenesulfonic acid salts, branched alkylbenzenes Sulfonates, alkylnaphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N -Alkylsulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate esters, Oxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxy Examples thereof include ethylene alkylphenyl ether phosphoric acid ester salts, saponification products of styrene-maleic anhydride copolymer, partial saponification products of olefin-maleic anhydride copolymer, and naphthalene sulfonate formalin condensates. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

  The cationic surfactant used in the developer is not particularly limited, and alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives and the like are preferably used.

  The nonionic surfactant used in the developer is not particularly limited, and is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct, naphthol ethylene oxide. Adducts, fatty acid ethylene oxide adducts, 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 copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer Rimmer, fatty acid esters of polyhydric alcohol type glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and alkyl-substituted or unsubstituted phenol ethylene oxide adducts and alkyl-substituted or unsubstituted naphthol ethylene oxide adducts are more preferable.

  The zwitterionic surfactant used in the developer is not particularly limited, and examples thereof include amine oxides such as alkyldimethylamine oxide, betaines such as alkylbetaines, and amino acids such as alkylamino fatty acid sodium. In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specific examples thereof are described in paragraph numbers [0255] to [0278] of JP-A-2008-203359, paragraph numbers [0028] to [0052] of JP-A-2008-276166, and the like. More preferable specific examples include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyldiaminoethylglycine hydrochloride, lauryldimethylaminoacetic acid betaine, N-lauric acid amidopropyldimethylbetaine, and N-lauric acid. And amidopropyldimethylamine oxide.

  Two or more surfactants may be used, and the content of the surfactant in the developer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

  Examples of the water-soluble polymer compound used in the developer include soybean polysaccharide, modified starch, gum arabic, dextrin, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and the like Derivatives, polyvinylpyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  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% by 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, and more preferably from 0.5 to 10% by mass.

  The developer can further contain a pH buffer. Any pH buffering agent can be used without particular limitation as long as it is a buffering agent that exhibits a buffering effect at pH 2-11. In the present invention, a weakly alkaline buffer is preferably used. For example, (a) a combination of carbonate ion-bicarbonate ion, (b) borate ion, or (c) water-soluble amine compound-ion of the amine compound ion. Examples include combinations. Due to the action of the pH buffering agent, fluctuations in pH can be suppressed even when the developer is used for a long period of time, and development deterioration due to fluctuations in pH, development debris generation and the like can be suppressed. Particularly preferred is a combination of carbonate ions and bicarbonate ions.

  In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and hydrogen carbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. The carbonate and bicarbonate are not particularly limited, but alkali metal salts are preferable. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. Alkali metals may be used alone or in combination of two or more. The total amount of carbonate ions and bicarbonate ions is preferably 0.05 to 5 mol / L, more preferably 0.1 to 2 mol / L, and particularly preferably 0.2 to 1 mol / L with respect to the total mass of the developer.

  The developer of the present invention may contain an organic solvent. Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ), Or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, tricrene, monochlorobenzene, etc.) and polar solvents. 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 monoethyl ether , Propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, methylphenyl carbinol, n-amyl Lucol, methyl amyl alcohol, 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.) Is mentioned.

  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 is preferably less than 40% by mass from the viewpoint of safety and flammability.

  In addition to the above, the developer may contain preservatives, chelate compounds, antifoaming agents, organic acids, inorganic acids, inorganic salts, and the like. Specifically, compounds described in paragraph numbers [0266] to [0270] of JP-A-2007-206217 can be preferably used.

  The developer can be used as a developer and a development replenisher for the exposed lithographic printing plate precursor, and is preferably applied to the above-described automatic development processor. When developing using an automatic developing processor, the developing solution becomes fatigued according to the amount of processing, and therefore the replenishing solution or fresh developing solution may be used to restore the processing capability.

  In the method for preparing a lithographic printing plate of the present invention, the entire lithographic printing plate precursor may be heated between exposure and development, if necessary. Such heating promotes an image forming reaction in the photosensitive layer, and may have advantages such as improvement of sensitivity and printing durability and stabilization of sensitivity. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. If the temperature is too high, problems such as curing to an unexposed part may occur. Very strong conditions are used for heating after development, and it is usually in the range of 100 to 500 ° C. If the temperature is low, sufficient image reinforcing action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image portion may occur.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Examples 1-22 and Comparative Examples 1-10
[Preparation of lithographic printing plate precursor]
(1) Production of Support A 0.3 mm thick aluminum plate (material JIS A1050) was etched by immersing it in a 10% by mass aqueous sodium hydroxide solution at 60 ° C. for 25 seconds, washed with running water, and then 20% by mass nitric acid. The solution was neutralized with an aqueous solution and then washed with water. The aluminum plate was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using an alternating waveform current of a sine wave at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / current density. A support was prepared by anodizing for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the condition of dm ² . When the center line average roughness of the support was measured using a needle having a diameter of 2 μm, it was 0.25 μm (Ra indication according to JIS B0601). (2) Formation of intermediate layer

Intermediate layers 1-8 (for comparison)
Water / methanol (1 / M) containing any one of the following polymer compounds A-1 to A-8 at an appropriate concentration (about 0.1% by mass) so that the coating amount after drying becomes 10 mg / m ^2. 9 mass ratio) solution was prepared, bar-coated on the support, and oven-dried at 80 ° C. for 10 seconds to form intermediate layers 1 to 8 (for comparison).

A-1 (Mass average molecular weight 100,000)
A-2 (mass average molecular weight 100,000)
A-3 (Mass average molecular weight 100,000)

A-4 Specific polymer compound 11 for intermediate layer (mass average molecular weight 100,000, composition ratio x = 100, y = 0)
A-5 Specific polymer compound 11 for intermediate layer (mass average molecular weight 100,000, composition ratio x = 90, y = 10)
A-6 Specific polymer compound 32 for intermediate layer (mass average molecular weight 100,000, composition ratio x = 20, y = 0, Z = 80)
A-7 Specific polymer compound 32 for intermediate layer (mass average molecular weight 100,000, composition ratio x = 20, y = 10, Z = 70)
A-8 Specific polymer compound 46 for intermediate layer (mass average molecular weight 100,000, composition ratio x = 20, y = 80)

Intermediate layer 9-16
Water / methanol (1 / M) containing any one of the above polymer compounds A-1 to A-8 at an appropriate concentration (about 0.1% by mass) so that the coating amount after drying is 10 mg / m ^2. 9 mass ratio) solution was prepared, bar-coated on the support, and oven dried at 80 ° C. for 10 seconds. Subsequently, an aqueous solution containing calcium chloride at an appropriate concentration (0.05 to 0.2% by mass) was applied with a bar so that the amount of calcium ions on the dried support was 1.8 mg / m ^2. , 80 ° C., oven-dried for 10 seconds to form the intermediate layers 9-16.

Intermediate layer 17-20
Water / methanol (1/9 mass ratio) containing the polymer compound A-1 or A-8 at an appropriate concentration (about 0.1 mass%) so that the coating amount after drying is 10 mg / m ^2. ) A solution was prepared, bar-coated on the support, and oven dried at 80 ° C. for 10 seconds. Subsequently, copper (II) chloride or aluminum chloride is contained at an appropriate concentration (0.05 to 0.2% by mass) so that the amount of cation on the support after drying is 1.8 mg / m ^2. The aqueous solution to be applied was bar-coated and oven-dried at 80 ° C. for 10 seconds to form intermediate layers 17-20.

Intermediate layers 21-22
Water / methanol (1/9 mass ratio) containing the polymer compound A-1 or A-8 at an appropriate concentration (about 0.1 mass%) so that the coating amount after drying is 10 mg / m ^2. ) A solution was prepared, bar-coated on the support, and oven dried at 80 ° C. for 10 seconds. Subsequently, a 20 ° C. aqueous solution containing calcium chloride at an appropriate concentration (0.05 to 0.2% by mass) so that the amount of calcium ion on the support after drying is 1.8 mg / m ^2. It was immersed for 10 seconds, rinsed with 20 ° C. demineralized water for 2 seconds, and dried to form intermediate layers 21-22.

Intermediate layer 23-24
Water / methanol (1/9 mass ratio) containing the polymer compound A-1 or A-8 at an appropriate concentration (about 0.1 mass%) so that the coating amount after drying is 10 mg / m ^2. ) Prepare a solution by adding calcium chloride to the solution at an appropriate concentration (0.05 to 0.2% by mass) so that the amount of calcium ion on the support after drying is 1.8 mg / m ^2. Then, a bar was coated on the support and oven-dried at 80 ° C. for 10 seconds to form intermediate layers 23 to 24.

Intermediate layer 25-26 (for comparison)
Water / methanol (1/1) containing the polymer compound A-1 or A-8 at an appropriate concentration (0.3 to 0.6% by mass) so that the coating amount after drying is 10 mg / m ^2. 9 mass ratio) The above support was immersed in a solution at 40 ° C. for 10 seconds, rinsed with 20 ° C. demineralized water for 2 seconds, and dried to form intermediate layers 25 to 26 (for comparison).

Intermediate layer 27-28
Water / methanol (1/1) containing the polymer compound A-1 or A-8 at an appropriate concentration (0.3 to 0.6% by mass) so that the coating amount after drying is 10 mg / m ^2. 9 mass ratio) The above support was immersed in a solution at 40 ° C. for 10 seconds, rinsed with 20 ° C. demineralized water for 2 seconds, and dried. Subsequently, a 20 ° C. aqueous solution containing calcium chloride at an appropriate concentration (0.05 to 0.2% by mass) so that the amount of calcium ions on the support after drying is 1.8 mg / m ^2. It was immersed for 10 seconds, rinsed with demineralized water for 2 seconds, and dried to form intermediate layers 27-28.

Intermediate layer 29-30
Water / methanol (1/1) containing the polymer compound A-1 or A-8 at an appropriate concentration (0.3 to 0.6% by mass) so that the coating amount after drying is 10 mg / m ^2. 9 mass ratio) The above support was immersed in a solution at 40 ° C. for 10 seconds, rinsed with 20 ° C. demineralized water for 2 seconds, and dried. Subsequently, an aqueous solution containing calcium chloride at an appropriate concentration (0.05 to 0.2% by mass) was applied with a bar so that the amount of calcium ions on the dried support was 1.8 mg / m ^2. , And oven-dried at 80 ° C. for 10 seconds to form intermediate layers 29-30.

Intermediate layers 31-32
Water / methanol (1/1) containing the polymer compound A-1 or A-8 at an appropriate concentration (0.3 to 0.6% by mass) so that the coating amount after drying is 10 mg / m ^2. 9 mass ratio) To the solution, calcium chloride was added at an appropriate concentration (0.05 to 0.2 mass%) so that the calcium ion amount on the support after drying was 1.8 mg / m ^2. A solution was prepared, the support was dipped at 40 ° C. for 10 seconds, rinsed with 20 ° C. demineralized water for 2 seconds, and dried to form intermediate layers 31 to 32.

(3) Formation of image recording layer and protective layer The following image recording layer coating solution (1) is bar-coated on the support on which each of the intermediate layers has been formed, and oven-dried at 100 ° C. for 44 seconds. An image recording layer of .3 g / m ² was formed. The following protective layer coating solution (1) was applied onto the image recording layer with a bar so that the dry coating amount was 0.8 g / m ² and dried at 125 ° C. for 70 seconds to obtain a lithographic printing plate precursor. .

<Image recording layer coating solution (1)>
・ The following binder polymer (1) (mass average molecular weight: 120,000) 0.54 g
・ The following polymerizable compound (1) 0.40 g
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (1) 0.18 g
・ The following chain transfer agent (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio: 83/17, mass average molecular weight: 60,000)): 10 parts by mass, solvent: cyclohexanone / methoxypropyl acetate / 1 -Methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt-The following fluorosurfactant (1) (mass average molecular weight: 11,000) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

<Protective layer coating solution (1)>
・ The following mica dispersion (1) 13.0 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
-Vinylpyrrolidone / vinyl acetate (molar ratio: 1/1) copolymer 0.05 g
(Mass average molecular weight: 70,000)
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

(Preparation of mica dispersion (1))
To 368 g of water, 32 g of synthetic mica (“Somasif ME-100”: manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added and dispersed using an homogenizer until the average particle size (laser scattering method) becomes 0.5 μm. A mica dispersion (1) was obtained.

[Preparation of planographic printing plate]
<Exposure, development and printing>
Each of the above lithographic printing plate precursors was image-exposed with a FFEI Violet semiconductor laser plate setter Vx9600 (equipped with InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW). The image was drawn at a resolution of 2438 dpi using an FM screen (TAFFETA 20) manufactured by FUJIFILM Corporation with a plate surface exposure of 0.05 mJ / cm ² .
Next, after preheating at 100 ° C. for 30 seconds, development processing was performed with an automatic development processor having a structure shown in FIG. The automatic developing processor has two rotating brush rolls, and the first brush roll is a brush roll having an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) are implanted. , 200 revolutions per minute in the same direction as the conveying direction (peripheral speed of the brush tip 0.52 m / sec), the second brush roll has a polybutylene terephthalate fiber (hair diameter 200 μm, hair A brush roll having an outer diameter of 50 mm in which a length of 17 mm) was implanted was used and rotated 200 times per minute (peripheral speed of the brush tip of 0.52 m / sec) in the direction opposite to the conveying direction. The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the printing plate. The tank capacity of the developer was 10 liters.

Developer (pH: 9.8)
7620g of water
Sodium carbonate anhydrous salt 100g
Sodium bicarbonate 50g
Softazoline LPB-R 1500g
(Amphoteric surfactant Kawaken Fine Chemicals Co., Ltd.)
Softazolin LAO 360g
(Amphoteric surfactant Kawaken Fine Chemicals Co., Ltd.)
150g sodium gluconate
TSA739 20g
(Antifoamer Momentive Performance Materials Co., Ltd.)
Ethylenediamine disuccinate 200g
0.1 g of 2-bromo-2-nitropropane-1,3-diol
0.1 g of 2-methyl-4-isothiazolin-3-one

  The developed lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (VEGRAVIOLET (manufactured by VEGRA) / water / isopropyl alcohol = 2/88/10 (volume ratio)) and host man (N ) Printing was performed at a printing speed of 6000 sheets per hour using black ink (manufactured by Hostman). For each lithographic printing plate, the printing durability of the image area and the stain resistance of the non-image area were evaluated as follows. The results are shown in Table 1. In Table 1, in the display of the formation method of the intermediate layer, A1 is application of the polymer compound solution, A2 is immersion in the polymer compound solution, B1 is application of the polyvalent cation solution, and B2 is polyvalent cation. Immersion in an ionic solution, AB1 means application of a solution containing a polymer compound and a polyvalent cation, and AB2 means immersion in a solution containing the polymer compound and a polyvalent cation.

<Print durability>
When the number of printed sheets was increased as described above, the image recording layer was gradually worn out and the ink acceptability 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.

<Stain resistance>
Printing was performed up to 500 sheets under the above printing conditions, and the stain resistance of the non-image area was evaluated in 11 stages from 1.0 points to 6.0 points. Four or more points are acceptable levels, and the larger the score, the better the stain resistance.

  From the results in Table 1, it can be seen that the printing plate having an intermediate layer containing a polyvalent cation has improved printing durability as compared with the printing plate having an intermediate layer not containing a polyvalent cation. This effect is recognized even when the type of the acid group and the polyvalent cation of the intermediate layer polymer compound is changed, and the carboxyl group which is the acid group of the binder polymer of the image recording layer and the acid group of the intermediate layer polymer compound. This is probably because the acid has an electrostatic interaction via a multivalent cation, so that higher adhesion of the image area is obtained. This effect is recognized even when the coating method of the intermediate layer polymer compound and the polyvalent cation is changed. Further, for example, from the comparison between Examples 15 and 21 and Examples 1, 13, 17, and 19, after the intermediate layer polymer compound was applied, the intermediate layer polymer compound and the polyvalent cation were applied simultaneously. It can be seen that coating the polyvalent cation is more effective (improving printing durability). This indicates that it is more preferable that multivalent ions exist at the interface between the intermediate layer and the image recording layer. Further, the improvement in the printing durability without deteriorating the stain resistance is considered to be because the electrostatic interaction via this cation is released during the development processing.

  Further, it can be seen that the stain resistance is slightly improved. This effect is unexpected. It is known that image recording layer components such as a binder polymer cause contamination by adsorbing to the support, but the presence of polyvalent cations at the interface allows the image recording layer components to be separated from the support surface. It is thought that it interacts with the polyvalent cation and is removed together with the cation during development.

  From the above results, it is found that an intermediate layer having an acid group-containing intermediate layer polymer compound and a polyvalent cation can provide a lithographic printing plate precursor having an excellent balance between stain resistance and printing durability. The

1: rotating brush roll 2: receiving roll 3: transport roll 4: transport guide plate 5: spray pipe 6: pipeline 7: filter 8: plate supply table 9: plate discharge table 10: developer tank 11: circulation pump 12: plate

Claims (16)

  A lithographic printing plate precursor comprising, on the support, an image recording layer containing (i) a polymerization initiator, (ii) a polymerizable compound, and (iii) a binder polymer, and a protective layer in this order, Between the image recording layer, an intermediate layer containing a polymer compound having at least one acid group selected from a sulfonic acid group, a carboxylic acid group and a phosphoric acid group or a salt thereof and a polyvalent cation is included. A lithographic printing plate precursor characterized by.   The lithographic printing plate precursor according to claim 1, wherein the acid group of the polymer compound is a carboxylic acid group or a sulfonic acid group.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the polymer compound further has a support-adsorptive group.   The lithographic printing plate precursor as claimed in claim 3, wherein the support-adsorptive group is any one of an onium base, a phosphoric acid group, a phosphonic acid group, a boric acid group, and a β-diketone group.   The lithographic printing plate precursor as claimed in claim 4, wherein the support-adsorptive group is a phosphate group.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein the polymer compound further has an ethylenically unsaturated bond group.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the polyvalent cation is a divalent or higher-valent alkaline earth metal ion or transition metal ion.   The lithographic printing plate precursor as claimed in claim 7, wherein the polyvalent cation is calcium ion, magnesium ion, copper (II) ion, aluminum ion or iron (II) ion.   The lithographic printing plate precursor as claimed in any one of claims 1 to 8, wherein the intermediate layer is formed by applying a coating solution containing the polymer compound and a polyvalent cation.   The said intermediate | middle layer apply | coats the coating liquid containing the said polyvalent cation after apply | coating the coating liquid containing the said high molecular compound, The any one of Claims 1-8 characterized by the above-mentioned. A lithographic printing plate precursor.   The said intermediate | middle layer is processed with the processing liquid containing the said polyvalent cation after apply | coating the coating liquid containing the said high molecular compound, The any one of Claims 1-8 characterized by the above-mentioned. A lithographic printing plate precursor.   The said intermediate | middle layer apply | coats the coating liquid containing the said polyvalent cation after processing with the processing liquid containing the said high molecular compound, The any one of Claims 1-8 characterized by the above-mentioned. A lithographic printing plate precursor.   The said intermediate | middle layer is processed with the process liquid containing the said polyvalent cation after processing with the process liquid containing the said high molecular compound, The any one of Claims 1-8 characterized by the above-mentioned. A lithographic printing plate precursor.   The lithographic printing plate precursor as claimed in any one of claims 1 to 8, wherein the intermediate layer is treated with a treatment liquid containing the polymer compound and a polyvalent cation.   A method for producing a lithographic printing plate, comprising treating the lithographic printing plate precursor according to any one of claims 1 to 14 with a developer having a pH of 2 to 11.   The lithographic printing plate preparation method according to claim 15, wherein the developer contains carbonate ions and hydrogen carbonate ions.

Images