JP2012200959A - Plate surface treating agent for lithographic printing plate, and method for treating lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate surface treating agent for a lithographic printing plate, with excellent stain proofness of a non-image part, and to provide a method for treating the lithographic printing plate.SOLUTION: This plate surface treating agent for a lithographic printing plate is characterized in that it contains a star polymer with: at least one support-adsorptive group; and at least one hydrophilic group.

Description

  The present invention relates to a lithographic printing plate surface treatment agent and a lithographic printing plate processing method.

Conventionally, a lithographic printing plate has a structure in which a photosensitive resin layer is provided on a support having a hydrophilic surface. As a plate-making method, usually, surface exposure (mask exposure) is performed through a lithographic film. The desired printing plate was obtained by removing the non-image area with a developer.
However, computer-to-plate that directly exposes the plate surface without using a lith film by scanning the plate surface according to digitized image information with highly directional light such as laser light by recent digitization technology. (CTP) technology has been developed, and a photosensitive lithographic printing plate (lithographic printing plate precursor) adapted to the technology has been developed.
Examples of the lithographic printing plate precursor suitable for exposure with such laser light include a lithographic printing plate precursor using a polymerizable photosensitive layer.
By selecting a photopolymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system), the polymerizable photosensitive layer can be easily increased in sensitivity as compared with other conventional photosensitive layers.
As the laser light source, a 405 nm or 830 nm semiconductor laser, an FD-YAG laser, or the like is used.
In recent years, CTP systems equipped with a 405 nm or 803 nm semiconductor laser have become widespread from the viewpoints of system cost and handling.

When making a lithographic printing plate, a plate surface treating agent (so-called gum solution) is applied in the final step in order to protect the non-image area and the image area. This process is called gumming.
For example, Patent Documents 1 to 3 are known as plate surface treating agents.
Patent Document 1 discloses a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing an ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support. A photosensitive lithographic printing plate characterized by being exposed and developed with a developer substantially free of silicate, and then subjected to plate surface treatment at 40 ° C. to 90 ° C. with a plate surface protective agent containing a phosphonic acid compound. A processing method is described.
Patent Document 2 discloses a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing a polymerizable ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support. After image exposure and development processing, (A) a plate surface protective agent containing a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more, and then heating at 50 ° C. to 200 ° C. A method for processing a photosensitive lithographic printing plate characterized by the following:
Further, in Patent Document 3, during the surface treatment and development treatment of the aluminum support, treatment is performed with a surface treatment agent or development treatment agent that does not substantially contain silicic acid or a salt thereof, and in the step after the development treatment, A processing method for a lithographic printing plate is described, wherein the processing is performed with a plate surface treating agent containing a compound having a phosphoric acid or phosphonic acid group in the molecule and having no film property itself.

  Patent Document 4 describes a printing chemical containing a water-soluble polymer having an adsorptive group and a sulfonic acid group that can be adsorbed on the surface of a lithographic printing plate support, as a printing chemical used for fountain solution.

  In Patent Document 5, as a plate surface treating agent, a monomer unit having at least one group selected from the group consisting of a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, and a salt thereof, a sulfonic acid group, a salt thereof, and an amide A lithographic printing plate surface treatment agent comprising a vinyl copolymer having a group and a monomer unit having at least one group or structure selected from the group consisting of a betaine structure, and the lithographic printing plate surface treatment agent The processing method of the lithographic printing plate used is described.

Patent Document 6 describes a lithographic printing plate precursor using a star polymer. It is described that developability and printing durability are improved by using the star polymer.
Patent Document 7 describes that a star polymer is used for the image forming layer in order to improve the on-press developability and printing durability of an on-press developable lithographic printing plate precursor. The printing plate precursor has high on-press developability and printing durability, but there is no description regarding an alkali development type printing plate.

JP 2006-11413 A Japanese Patent Laid-Open No. 2005-114892 JP 2007-45114 A JP 2007-38483 A JP 2010-284963 A JP 2004-317543 A JP 2007-249036 A

  An object of the present invention is to provide a lithographic printing plate surface treatment agent having excellent anti-staining properties for non-image areas and a lithographic printing plate processing method.

The above-described problems of the present invention have been solved by the means described in <1> or <9> below.
It is described below together with <2> to <8>, <10> and <11> which are preferred embodiments.
<1> A lithographic printing plate surface treatment agent comprising a star polymer having at least one support-adsorbing group and at least one hydrophilic group.
<2> The plate surface treating agent for a lithographic printing plate as described in <1>, wherein the star polymer is a star polymer having 3 to 10 branches.
<3> The lithographic printing as described in <1> or <2> above, wherein the star polymer has a polymer chain branched from 3 branches to 10 branches from the central skeleton via a sulfide bond Plate surface treatment agent for printing plates.
<4> The star polymer is obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polyfunctional thiol, and the polymer chain is branched from 3 to 10 branches from the central skeleton through a sulfide bond. The plate surface treating agent for a lithographic printing plate according to any one of <1> to <3>, wherein the plate surface treating agent is a polymer.
<5> The support adsorbing group of the star polymer is at least one group selected from a phosphonic acid group and a salt thereof, a phosphate ester group and a salt thereof, and a carboxylic acid group and a salt thereof. The plate surface treating agent for a lithographic printing plate according to any one of <1> to <4>, wherein
<6> The hydrophilic group of the star polymer is a sulfonic acid group and a salt thereof, an amide group, a polyalkylene oxide group, a hydroxyl group, a sulfuric monoester group and a salt thereof, a phosphonium group, a sulfonamide group, an amino group, The plate surface treating agent for a lithographic printing plate as described in any one of <1> to <5> above, which is at least one group selected from a monoamide group of sulfuric acid and a salt thereof, and a betaine structure .
<7> The plate surface treatment agent for a lithographic printing plate as described in <7> above, comprising a water-soluble polymer compound and at least one selected from a phosphate and phosphoric acid.
<8> The water-soluble polymer compound is gum arabic, a fiber derivative and a modified product thereof, polyvinyl alcohol and a derivative thereof, polyvinyl pyrrolidone, a vinyl methyl ether / maleic anhydride copolymer, and a vinyl acetate / maleic anhydride copolymer. Water-soluble at least one selected from the group consisting of a polymer, a styrene / maleic anhydride copolymer, a water-soluble soybean polysaccharide, starch, starch derivatives, pullulan and pullulan derivatives, gelatin, and hemicellulose extracted from soybeans The plate surface treating agent for a lithographic printing plate as described in any one of <1> to <7> above, which is a polymer compound.
<9> A plate surface using the plate surface treating agent for a lithographic printing plate according to any one of <1> to <8>, and a step of exposing the lithographic printing plate precursor to an image, a step of developing with a developer, and A method for processing a lithographic printing plate including a processing step.
<10> The method for processing a lithographic printing plate as described in <9>, wherein the lithographic printing plate precursor has a support subjected to an electrochemical surface roughening treatment with an aqueous hydrochloric acid solution.
<11> The method for processing a lithographic printing plate according to <9> or <10>, wherein the lithographic printing plate precursor has a photosensitive layer containing a sensitizing dye, a polymerization initiator, and a binder polymer.

  ADVANTAGE OF THE INVENTION According to this invention, the plate surface processing agent for lithographic printing plates excellent in the antifouling property of a non-image part and the processing method of a lithographic printing plate can be provided.

It is a schematic diagram of the star polymer of the present invention.

  Hereinafter, the plate surface treating agent for a lithographic printing plate and the processing method of the lithographic printing plate of the present invention will be described in detail.

[Plate surface treatment agent for lithographic printing plates]
The plate surface treating agent for lithographic printing plates of the present invention (hereinafter also simply referred to as “plate surface treating agent”, also referred to as “plate surface protecting agent” or “finisher”) has at least one support-adsorbing group and at least one. It comprises a star polymer having two hydrophilic groups.

[I] Star Polymer The star polymer used in the present invention is a polymer having a main chain structure as shown in the schematic diagram of FIG. One end of the polymer chain Pl has a structure bonded to the central skeleton A.

  As long as the star polymer used in the present invention has the structure as described above, any star polymer can be used. Examples of such star polymers include star polymers obtained by the coupling method and anion growth method described in “New Experimental Chemistry Course, Polymer Chemistry I”, edited by The Chemical Society of Japan, p. 208-210, and JP-A-10-279867. A star-shaped polymer obtained by a synthesis method in which a polymerization reaction is carried out under light irradiation using a compound containing a dithiocarbamate group and / or a compound containing a xanthate group described in the gazette as an initiator, or a polyfunctional thiol as a chain transfer agent And a star polymer obtained by ordinary radical polymerization.

  As the star polymer of the present invention, from the viewpoint of ease of synthesis and the performance of the obtained polymer, it is obtained from the central skeleton via a sulfide bond obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polyfunctional thiol. A polymer having a branched polymer chain is preferred. That is, those having a hub portion that is a residue of a thiol having 3 or more functionalities as a central skeleton are preferable. In an idealized structure, the addition polymer backbone extends from each thio moiety in the hub. Therefore, three or more main chains extend from the thio moiety. That is, the central skeleton A preferably has a structure represented by the following general formula (1).

Here, A ₁ is an n-valent organic group, and n is an integer of 3 or more. Specific examples of A ₁ include the following structures or organic groups constituted by combining a plurality of these structures. n is preferably an integer of 3 to 10, more preferably an integer of 3 to 8, and particularly preferably an integer of 4 to 8.

(Central skeleton of polymer with polymer chain branched via sulfide bond)
As the polyfunctional thiol used in the star polymer of the present invention, any compound having a plurality of thiol groups in one molecule can be suitably used. Are preferred, more preferably trifunctional to 8-functional thiols, particularly preferably trifunctional to 6-functional thiols. Examples of the polyfunctional thiol include the following (Compound A) to (Compound F).

(Compound A)
Compound A is a compound obtained by a method in which an electrophile such as a halide or a sulfonic acid ester of alcohol is reacted with a sulfurizing agent such as thiourea, potassium thiocyanate, or thioacetic acid, followed by various treatments. Specific examples of compound A include the following compounds, but the present invention is not limited thereto.

(Compound B)
Compound B is a compound obtained by a dehydration condensation reaction between a polyfunctional alcohol and a carboxylic acid having a thiol group. Among them, a polyfunctional alcohol having 3 to 10 functionals and a monocarboxylic acid having one thiol group A compound obtained by a condensation reaction is preferred.

  Specific examples of the polyfunctional alcohol include cyclohexanetriol (3), glycerol (3), 2-hydroxymethyl-1,3-propanediol (3), 1,1,1-tris (hydroxymethyl) ethane (3). 1,2,4-butanetriol (3), trimethylolpropane (3), 1,2,3-trihydroxyhexane (3), 1,2,6-trihydroxyhexane (3), 1,2, 3-heptanetriol (3), pyrogallol (3), 1,2,4-benzenetriol (3), phloroglucinol (3), 1,1,1-tris (4-hydroxyphenyl) ethane (3), 1,3,5-tris (2-hydroxyethyl) isocyanurate (3), pentaerythritol (4), threitol (4), erythritol (4), xylulo (4), ribulose (4), quebrachitol (5), adonitol (5), arabitol (5), xylitol (5), catechin (5), epicatechin (5), inositol (6), sorbitol ( 6), mannitol (6), iditol (6), dulcitol (6), dipentaerythritol (6), tripentaerythritol (8). In addition, the number in () shows the number of functional groups.

Among these polyfunctional alcohols, cyclohexanetriol, glycerol (3), 2-hydroxymethyl-1,3-propanediol (3), 1,1,1-tris (hydroxymethyl) ethane (3), trimethylolpropane (3), Phloroglucinol (3), 1,1,1-tris (4-hydroxyphenyl) ethane (3), 1,3,5-tris (2-hydroxyethyl) isocyanurate (3), pentaerythritol (4), catechin (5), epicatechin (5), inositol (6), dipentaerythritol (6), tripentaerythritol (8) are preferred,
Cyclohexanetriol, 2-hydroxymethyl-1,3-propanediol (3), 1,1,1-tris (hydroxymethyl) ethane (3), trimethylolpropane (3), phloroglucinol (3), 1, 1,1-tris (4-hydroxyphenyl) ethane (3), 1,3,5-tris (2-hydroxyethyl) isocyanurate (3), pentaerythritol (4), catechin (5), epicatechin (5 ), Inositol (6), dipentaerythritol (6), tripentaerythritol (8) are more preferred,
1,3,5-tris (2-hydroxyethyl) isocyanurate (3), pentaerythritol (4), catechin (5), epicatechin (5), inositol (6), dipentaerythritol (6), tripenta Erythritol (8) is particularly preferred.

Specific examples of monocarboxylic acids having one thiol group include mercaptoacetic acid, 3-mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, and N- (2-mercaptopropionyl) glycine. And thiosalicylic acid.
Mercaptoacetic acid, 3-mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, N- (2-mercaptopropionyl) glycine are preferred, 3-mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, and N- (2-mercaptopropionyl) glycine are more preferable, and 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, and N- (2-mercaptopropionyl) glycine Is particularly preferred.
Specific examples of compound B include the following compounds, but are not limited thereto.

Among the specific examples in Table 1, SB-1 to SB-34, SB-36 to SB-48, SB-50 to SB-55, SB-57 to SB-62, and SB-64 to SB- are preferable. 69, SB-71 to SB-76, SB-78 to SB-111, SB-113 to SB-118, SB-120 to SB-125, SB-127 to SB-132, SB-134 to SB-139, SB-141 to SB-146, SB-148 to SB-153, SB-155 to SB-181, SB-183 to SB-188, SB-190 to SB-195, SB-197 to SB-202, SB- 204 to SB-217,
More preferred are SB-1 to SB-6, SB-9 to SB-13, SB-15 to SB-20, SB-22 to SB-27, SB-36 to SB-41, SB-78 to SB. -83, SB-85-SB-90, SB-92-SB-97, SB-99-SB-104, SB-155-SB-160, SB-162-SB-167, SB-169-SB-174 , SB-204 to SB-209, SB-211 to SB-216,
Particularly preferred are SB-2 to SB-6, SB-16 to SB-20, SB-23 to SB-27, SB-37 to SB-41, SB-79 to SB-83, SB-86 to SB. -90, SB-93 to SB-97, SB-100 to SB-104, SB-156 to SB-160, SB-163 to SB-167, SB-170 to SB-174, SB-205 to SB-209 , SB-212 to SB-216.
Since these polyfunctional thiols have a long distance between thiol groups and a small steric hindrance, they can form a desired star structure.

(Compound C)
Compound C is a compound obtained by a dehydration condensation reaction between a polyfunctional amine and a carboxylic acid having a thiol group. Among these, a compound obtained by a condensation reaction between a polyfunctional amine having 3 to 10 functional groups and a monocarboxylic acid having one thiol group is preferable.

  Specific examples of the polyfunctional amine include diethylenetriamine (3), N- (2-aminoethyl) -1,3-propanediamine (3), N- (3-aminopropyl) -1,3-propanediamine (3). , Spermidine (3), bis (hexamethylene) triamine (3), 4- (aminomethyl) -1,8-octanediamine (3), triethylenetetramine (4), 1,4,7,11-tetraaza Undecane (4), N, N'-bis (3-aminopropyl) ethylenediamine (4), N, N'-bis (2-aminoethyl) -1,3-propanediamine (4), N, N'- Bis (3-aminopropyl) -1,3-propanediamine (4), spermine (4), tris (2-aminoethyl) amine (3), tetraethylenepentamine (5), pentaethylene Xamine (6), 1,4,7-triazacyclononane (3), 1,5,9-triazacyclododecane (3), cyclen (4), 1,4,8,11-tetraazacyclotetradecane (4), 1,4,8,12-tetraazacyclopentadecane (4), hexacyclene (6), 3,3′-diaminobenzidine (4), 1,2,4,5-benzenetetramine (4 ).

Among these polyfunctional amines, 4- (aminomethyl) -1,8-octanediamine (3), triethylenetetramine (4), 1,4,7,11-tetraazaundecane (4), N, N ′ -Bis (3-aminopropyl) ethylenediamine (4), N, N'-bis (2-aminoethyl) -1,3-propanediamine (4), N, N'-bis (3-aminopropyl) -1 , 3-propanediamine (4), spermine (4), tris (2-aminoethyl) amine (3), tetraethylenepentamine (5), pentaethylenehexamine (6), cyclen (4), hexacyclene ( 6) is preferred,
4- (aminomethyl) -1,8-octanediamine (3), tris (2-aminoethyl) amine (3), tetraethylenepentamine (5), pentaethylenehexamine (6), cyclen (4), hexa More preferred is cyclen (6),
Tetraethylenepentamine (5), pentaethylenehexamine (6), cyclen (4), and hexacyclene (6) are particularly preferred.

  Specific examples of the carboxylic acid having a thiol group include the carboxylic acids described in Compound B above. Specific examples of this compound include the following compounds. The present invention is not limited to these.

Among the specific examples in Table 2, SC-1 to SC-6, SC-8 to SC-13, SC-15 to SC-20, SC-22 to SC-27, SC-29 to SC- are preferable. 34, SC-36 to SC-111, SC-113 to SC-118, SC-120 to SC-132, SC-134 to SC-139, SC-141 to SC-147,
More preferred are SC-37 to SC-41, SC-44 to SC-48, SC-51 to SC-55, SC-58 to SC-62, SC-65 to SC-69, SC-72 to SC-. 76, SC-79 to SC-83, SC-86 to SC-90, SC-93 to SC-97, SC-100 to SC-104, SC-121 to SC-125, SC-142 to SC-146 Yes,
Particularly preferred are SC-37 to SC-41, SC-86 to SC-90, SC-93 to SC-97, SC-100 to SC-104, SC-121 to SC-125, SC-142 to SC-. 146.

  Since these polyfunctional thiols have a long distance between thiol groups and a small steric hindrance, they can form a desired star structure.

(Compound D)
Compound D is a compound obtained by a dehydration condensation reaction between a compound having an alcohol and an amine and a carboxylic acid having a thiol group, and has one polyfunctional alcohol amine having 3 to 10 functional alcohols and amines and one thiol group. A compound obtained by a condensation reaction with a monocarboxylic acid is preferred.

Specific examples of the polyfunctional alcohol amine include diethanolamine (3), serinol (3), diisopropanolamine (3), 2-amino-2-ethyl-1,3-propanediol (3), and 2-amino-2. -Methyl-1,3-propanediol (3), tris (hydroxymethyl) aminomethane (4), bis-homotris (4), 1,3-diamino-2-hydroxypropane (3), 2- (2- Aminoethylamino) ethanol (3), N, N′-bis (2-hydroxyethyl) ethylenediamine (4), 1,3-bis [tris (hydroxymethyl) methylamino] propane (8), 1-amino-1 -Deoxy-D-sorbitol (6), N-methyl-D-glucamine (6), 2,3-diaminophenol (3), 4-aminoresorcinol (3), norphenylephrine (3), octopamine (3), synephrine (3), 3,4-dihydroxybenzylamine (3), 3-hydroxytyramine (3), norephinephrine (4), 5-hydroxydopamine (4), 6-hydroxydopamine (4), and the like.
Serinol (3), 2-amino-2-methyl-1,3-propanediol (3), tris (hydroxymethyl) aminomethane (4), bis-homotris (4), 1,3-diamino-2-hydroxy Propane (3), N, N′-bis (2-hydroxyethyl) ethylenediamine (4), 1,3-bis [tris (hydroxymethyl) methylamino] propane (8), 1-amino-1-deoxy-D -Sorbitol (6), N-methyl-D-glucamine (6), norephinephrine (4), 5-hydroxydopamine (4), 6-hydroxydopamine (4) are preferred,
Tris (hydroxymethyl) aminomethane (4), bis-homotris (4), N, N′-bis (2-hydroxyethyl) ethylenediamine (4), 1,3-bis [tris (hydroxymethyl) methylamino] propane (8), 1-amino-1-deoxy-D-sorbitol (6), N-methyl-D-glucamine (6), norephinephrine (4), 5-hydroxydopamine (4), 6-hydroxydopamine ( 4) is particularly preferred.

  Specific examples of the carboxylic acid having a thiol group include the carboxylic acids described in Compound B above. Specific examples of this compound include the following compounds. The present invention is not limited to these.

Among the specific examples in Table 3, SD-1 to SD-6, SD-8 to SD-20, SD-22 to SD-27, SD-29 to SD-62, SD-64 to SD- are preferable. 97, SD-99 to SD-104, SD-106 to SD-111, SD-113 to SD-118, SD-120 to SD-125, SD-127 to SD-132, SD-134 to SD-139, SD-141 to SD-161,
More preferably, SD-9 to SD-13, SD-30 to SD-34, SD-37 to SD-41, SD-44 to SD-48, SD-51 to SD-55, SD-65 to SD- 69, SD-72 to SD-76, SD-79 to SD-83, SD-86 to SD-90, SD-142 to SD-146, SD-149 to SD-153, SD-156 to SD-160 Yes,
Particularly preferred are SD-37 to SD-41, SD-44 to SD-48, SD-65 to SD-69, SD-72 to SD-76, SD-79 to SD-83, SD-86 to SD. -90, SD-142 to SD-146, SD-149 to SD-153, SD-156 to SD-160.

  Since these polyfunctional thiols have a long distance between thiol groups and a small steric hindrance, they can form a desired star structure.

(Compound E)
Compound E is a compound obtained by a dehydration condensation reaction between a polyfunctional carboxylic acid and an alcohol having a thiol group. Among them, a polyfunctional carboxylic acid having 2 to 10 functionalities and an alcohol having one or more thiol groups A compound obtained by a condensation reaction is preferred.

Specific examples of the polyfunctional carboxylic acid include oxalic acid (2), malonic acid (2), methyl malonic acid (2), succinic acid (2), methyl succinic acid (2), glutaric acid (2), adipic acid ( 2), pimelic acid (2), suberic acid (2), azelaic acid (2), sebacic acid (2), tricarbaliphosphoric acid (3), 1,2,3,4-butanetetracarboxylic acid (4) , Aconitic acid (3), hexafluoroglutaric acid (2), malic acid (2), tartaric acid (2), citric acid (3), diglycolic acid (2), 3,6-dioxaoctanedicarboxylic acid (2 ), Tetrahydrofuran-2,3,4,5-tetracarboxylic acid (4), mercaptosuccinic acid (2), thiodiglycolic acid (2), 2,2 ′, 2 ″, 2 ′ ″-[1,2 -Ethanediylidenetetrakis (thio)] tetrakisacetic acid 4), 1,3,5-cyclohexanetricarboxylic acid (3), 1,2,3,4-cyclobutanetetracarboxylic acid (4), 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (6 ), 1,2-phenylenediacetic acid (2), 1,2-phenylenedioxydiacetic acid (2), homophthalic acid (2), 1,3-phenylenediacetic acid (2), 4-carboxyphenoxyacetic acid (2) ), 1,4-phenylenediacetic acid (2), 1,4-phenylenedipropionic acid (2), phthalic acid (2), isophthalic acid (2), terephthalic acid (2), 1,2,3-benzene Tricarboxylic acid (3), 1,2,4-benzenetricarboxylic acid (3), 1,3,5-benzenetricarboxylic acid (3), 1,2,4,5-benzenetetracarboxylic acid (4), melittic acid (6), 1, 4, 5, 8-na Phthalene tetracarboxylic acid (4),
Tricarbaliphosphoric acid (3), 1,2,3,4-butanetetracarboxylic acid (4), aconitic acid (3), citric acid (3), tetrahydrofuran-2,3,4,5-tetracarboxylic acid ( 4), mercaptosuccinic acid (2), 2,2 ′, 2 ″, 2 ′ ″-[1,2-ethanediylidenetetrakis (thio)] tetrakisacetic acid (4), 1,3,5-cyclohexanetricarboxylic acid (3), 1,2,3,4-cyclobutanetetracarboxylic acid (4), 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (6), 1,2-phenylenediacetic acid (2) 1,2-phenylenedioxydiacetic acid (2), 1,3-phenylenediacetic acid (2), 1,4-phenylenediacetic acid (2), 1,4-phenylenedipropionic acid (2), phthalic acid (2), isophthalic acid (2), terephthalate Acid (2), 1,3,5-benzenetricarboxylic acid (3), 1,2,4,5-benzenetetracarboxylic acid (4), melittic acid (6), 1,4,5,8-naphthalenetetra Carboxylic acid (4) is preferred,
Tricarbaliphosphoric acid (3), 1,2,3,4-butanetetracarboxylic acid (4), tetrahydrofuran-2,3,4,5-tetracarboxylic acid (4), mercaptosuccinic acid (2), 2, 2 ′, 2 ″, 2 ′ ″-[1,2-ethanediylidenetetrakis (thio)] tetrakisacetic acid (4), 1,3,5-cyclohexanetricarboxylic acid (3), 1,2,3,4 Cyclobutanetetracarboxylic acid (4), 1,2,3,4,5,6-cyclohexanehexacarboxylic acid (6), 1,3,5-benzenetricarboxylic acid (3), 1,2,4,5-benzene Tetracarboxylic acid (4), melittic acid (6) and 1,4,5,8-naphthalenetetracarboxylic acid (4) are particularly preferred.

Specific examples of the alcohol having a thiol group include 2-mercaptoethanol (1), 1-mercapto-2-propanol (1), 3-mercapto-1-propanol (1), 3-mercapto-2-butanol (1 ), 2,3-dimercapto-1-propanol (2), 4-hydroxythiophenol (1), 2-mercaptoethanol (1), 3-mercapto-1-propanol (1), 2,3- Dimercapto-1-propanol (2) is preferred,
2-mercaptoethanol (1) and 3-mercapto-1-propanol (1) are more preferable, and 3-mercapto-1-propanol (1) is particularly preferable.

  Examples of this compound include, but are not limited to, the compounds listed in Table 4 and Table 5 below.

Of the specific examples in Tables 4 and 5, SE-12, SE-14, SE-16, SE-18, SE-20, SE-22, SE-24, SE-26, SE-33, SE-35, SE-41, SE-43, SE-45, SE-119, SE-121, SE-47, SE-49, SE-51, SE-53, SE-55, SE-57, SE- 59, SE-61, SE-63, SE-65, SE-67, SE-69, SE-71, SE-83, SE-85, SE-89, SE-91, SE-95, SE-97, SE-99, SE-101, SE-103, SE-105, SE-107, SE-109, SE-111, SE-113, SE-115, SE-117,
More preferably, SE-12, SE-14, SE-18, SE-20, SE-41, SE-43, SE-119, SE-121, SE-49, SE-51, SE-55, SE -57, SE-61, SE-63, SE-67, SE-69, SE-95, SE-97, SE-101, SE-103, SE-107, SE-109, SE-113, SE-115 It is.

  Since these polyfunctional thiols have a long distance between thiol groups and a small steric hindrance, they can form a desired star structure.

(Compound F)
Compound F is a compound obtained by a dehydration condensation reaction between a polyfunctional carboxylic acid and an amine having a thiol group. Among them, a polyfunctional carboxylic acid having 2 to 10 functionals and an amine having one or more thiol groups A compound obtained by a condensation reaction is preferred.

  Specific examples of the polyfunctional carboxylic acid include the aforementioned polyfunctional carboxylic acid. Specific examples of amines having one or more thiol groups include 2-aminoethanethiol, 2-aminothiophenol, 3-aminothiophenol, 4-aminothiophenol, 2-aminoethanethiol, 4-amino Thiophenol is preferred, and 2-aminoethanethiol is more preferred.

  The following compounds are mentioned as an example of this compound. The present invention is not limited to these.

  Among the specific examples in Table 6, SF-1, SF-4, SF-5, SF-8, SF-9, SF-13, SF-17, SF-20, SF-21, SF- are preferable. 24, SF-25, SF-28, SF-29, SF-32, SF-33, SF-36, SF-37, SF-40, SF-41, SF-45, SF-49, SF-52, SF-53, SF-56, SF-57, SF-60, SF-61, and SF-64 are preferable, and SF-1, SF-5, SF-17, SF-21, and SF-25 are more preferable. SF-29, SF-33, SF-37, SF-49, SF-53, SF-57, and SF-61.

  Since these polyfunctional thiols have a long distance between thiol groups and a small steric hindrance, they can form a desired star structure.

  Among these polyfunctional thiols, Compound A to Compound E are preferable from the viewpoint of printing durability and developability, Compound A, Compound B, Compound C, and Compound E are more preferable, and Compound A, Compound B, and Compound C are particularly preferable. .

[Polymer chain]
Examples of the polymer chain in the star polymer of the present invention include known vinyl polymers, (meth) acrylic acid polymers, and styrene polymers that can be produced by radical polymerization, with (meth) acrylic acid polymers being particularly preferred.

(Support adsorbing group)
The polymer chain used in the present invention contains, as a copolymerization component, a repeating unit having at least one functional group that interacts with the surface of the support in order to improve the adhesion to the support. Examples of functional groups that interact with the support surface include ionic bonds, hydrogen bonds, and polar interactions with metals, metal oxides, hydroxyl groups, and the like that exist on a support that has been anodized or hydrophilized. Groups capable of interacting with each other.
Specific examples of functional groups that interact with the support surface are listed below.

In the formula, M ¹ and M ² each independently represent a hydrogen atom, a metal atom contained in an alkali metal or an alkaline earth metal, or an ammonium group. From the viewpoint of dirtiness, at least one of the functional groups that interact with the support surface is a phosphonic acid group or a salt thereof (Structure 1), a phosphate ester group or a salt thereof (Structure 2), a carboxylic acid group or a salt thereof. A salt is preferable, and a phosphate group or a salt thereof, or a phosphonic acid group or a salt thereof is preferable. In the present invention, the repeating unit having at least one functional group that interacts with the support surface is specifically preferably represented by the following general formula (B1).

^Wherein each R a to R ^c are independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. Q represents a functional group that interacts with the support surface, and the preferred embodiment is the same as described above.
L is a single bond or a divalent linking group. A divalent linking group can be from 1 to 60 carbon atoms, 0 to 10 nitrogen atoms, 0 to 50 oxygen atoms, 1 to 100 hydrogen atoms, and 0 to It can be composed of up to 20 sulfur atoms, and more specifically, a combination of the following structural units.

In the above structure, R ^d and R ^e represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogen atom. n represents an integer of 1 to 4.

  Specific examples of the repeating unit having at least one functional group that interacts with the support surface used in the present invention are shown below, but the present invention is not limited thereto.

The support adsorptive group in the star polymer of the present invention may be only one kind in the star polymer, or two or more kinds.
The content ratio of the monomer unit having a support-adsorptive group in the star polymer that can be used in the present invention is preferably 2 to 80 mol% with respect to the total monomer units of the star polymer, It is more preferably mol%, more preferably 5 to 50 mol%, and particularly preferably 10 to 40 mol%.

(Hydrophilic group)
The polymer chain of the star polymer of the present invention contains a repeating unit having a hydrophilic group as a copolymerization component in order to increase the hydrophilicity of the support surface and improve the soiling property.
Specific examples of the hydrophilic group are given below.

In the above formula, M ¹ represents a hydrogen atom, a metal atom contained in an alkali metal or alkaline earth metal, or an ammonium group.
X ⁺ is a group represented by -N ⁺ R ₁ R _2- , -S ⁺ R _1- , -I ⁺ -, or -P ⁺ R ₁ R _2- .
R ₁ and R ₂ each independently represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group or an alkynyl group, R ₃ represents an alkylene group, and R ₄ represents an alkyl group, an aryl group, an alkenyl group or an alkynyl group. Represents.
n represents an integer of 1 to 100. L is as defined above.

  As the hydrophilic group, any functional group having high affinity with water can be suitably used. However, a sulfonic acid (salt) group, an amide group, a polyalkylene oxide group, a hydroxyl group, and a monosulfuric acid group can be used. Ester (salt) group, sulfonamide group, amino group, sulfuric monoamide (salt) group, betaine structure is preferable, sulfonic acid (salt) group, amide group, polyalkylene oxide group, hydroxyl group, sulfuric monoester (salt) group , Sulfonamido group, amino group, sulfuric monoamide (salt) group and betaine structure are more preferred, and sulfonic acid (salt) group, amide group, polyalkylene oxide group, hydroxyl group and betaine structure are particularly preferred.

  In the present invention, the repeating unit having a hydrophilic group is preferably represented by the following general formula (B2).

^Wherein each R a to R ^c are independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom. L is as defined above. W represents a hydrophilic group, and preferred embodiments are the same as those described above.

  Specific examples of the repeating unit having a hydrophilic group used in the present invention are shown below, but the present invention is not limited thereto.

The star polymer that can be used in the present invention may have only one type of hydrophilic monomer unit or may have two or more types of hydrophilic monomer units.
The content ratio of the hydrophilic monomer unit in the star polymer that can be used in the present invention is preferably 30 to 98 mol%, and preferably 40 to 90 mol%, based on all monomer units of the star polymer. Is more preferable, and it is still more preferable that it is 50-90 mol%.

(Other repeat units)
The polymer chain of the star polymer used in the present invention may be a copolymer having another repeating unit other than those described above (hereinafter sometimes simply referred to as “other repeating unit”). Here, examples of other repeating units include repeating units derived from various known monomers.

The polymer chain used in the present invention is a polymer unit having a support adsorbing property, a polymer unit having a hydrophilic group, a polymer unit of alkyl (meth) acrylate or aralkyl ester, (meth) acrylamide or a derivative thereof. May have a polymerization unit of α-hydroxymethyl acrylate, a polymerization unit of styrene derivative.
The alkyl group of the (meth) acrylic acid alkyl ester is preferably an alkyl group having 1 to 5 carbon atoms and an alkyl group having the above-described substituent having 2 to 8 carbon atoms, and a methyl group is more preferable. Examples of (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.
Examples of (meth) acrylamide derivatives include N-isopropylacrylamide, N-phenylmethacrylamide, N- (4-methoxycarbonylphenyl) methacrylamide, N, N-dimethylacrylamide, morpholinoacrylamide and the like.
Examples of the α-hydroxymethyl acrylate include ethyl α-hydroxymethyl acrylate and cyclohexyl α-hydroxymethyl acrylate. Examples of styrene derivatives include styrene and 4-tertbutylstyrene.

  The content ratio of other monomer units in the star polymer that can be used in the present invention is preferably 40 mol% or less, more preferably 30 mol%, based on all monomer units of the star polymer. More preferably, it is 20 mol% or less.

As a combination of a repeating unit of a support-adsorbing group and a repeating unit of a hydrophilic group that can be used in the present invention, the support-adsorbing group is a phosphonic acid group or a salt thereof, a phosphate ester group or a salt thereof, or a carboxyl group. It is preferable that the acid group or a salt thereof and the hydrophilic group are a sulfonic acid group or a salt thereof, an amide group, a polyalkylene oxide group, a hydroxyl group, or a betaine structure,
More preferably, the support-adsorptive group is a phosphonic acid group or a salt thereof, a phosphate ester group or a salt thereof, and the hydrophilic group is a sulfonic acid group or a salt thereof, a polyalkylene oxide group, a hydroxyl group, or a betaine structure. Preferably
It is particularly preferred that the support adsorptive group is a phosphonic acid group or a salt thereof, a phosphate ester group or a salt thereof, and a hydrophilic group is a sulfonic acid group or a salt thereof, a polyalkylene oxide group, or a hydroxyl group.

The mass average molar mass (Mw) of the star polymer is preferably 5,000 or more, more preferably 10,000 or more, and preferably 1,000,000 or less, More preferably, it is 000 or less.
The number average molar mass (Mn) of the star polymer is preferably 1,000 or more, more preferably 2,000 or more, and preferably 500,000 or less, 300,000. The following is more preferable.
The polydispersity (Mw / Mn) of the star polymer is preferably 1.1-10.

  Specific examples of the star polymer used in the present invention are shown in Tables 7 to 9 below, but the present invention is not limited thereto.

The plate surface treating agent of the present invention may contain one star polymer alone or two or more star polymers.
The content of the star polymer in the plate surface treating agent of the present invention is preferably 0.005 to 10% by mass, more preferably 0.01 to 5% by mass, and 0.1 to 3% by mass. More preferably it is. Within the above range, a higher anti-staining effect can be obtained in the non-image area and the network image area.

[II] Other components In the plate surface treating agent of the present invention, in addition to the star polymer, other components, water-soluble polymer compounds, inorganic acids, inorganic acid salts, organic acids, organic acid salts, other than the above compounds Surfactants, organic solvents, nitrates, sulfates, chelating agents, preservatives, antifoaming agents, and the like.
Various components are described below.

To the plate surface treating agent of the present invention, it is preferable to add a water-soluble polymer compound other than the star polymer having film-forming properties in order to maintain hydrophilicity and protect the plate surface from scratches.
The star polymer may be water-soluble or not water-soluble, but is preferably water-soluble.

  Examples of water-soluble polymer compounds other than the star polymer include gum arabic, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, hydroxypropylcellulose, methylpropylcellulose, etc.) and modified products thereof, polyvinyl alcohol and Derivatives thereof, polyvinylpyrrolidone, polyacrylamide, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, starch derivatives (eg dextrin, maltodextrin, enzyme Degraded dextrin, hydroxypropylated starch, hydroxypropylated starch enzymatically degraded dextrin, carboxydimethylated starch, phosphorylated starch, cyclodextrin), pullulan and pullulan Conductor, and the like.

  Other starch derivatives that can be used as water-soluble polymer compounds include roasted starch such as British gum, enzyme-modified dextrins such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, and modified starch. Pregelatinized starch such as alpha starch and non-modified pregelatinized starch, phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch and carbamate starch, carboxyalkyl starch, hydroxyalkyl starch, sulfo Alkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl starch, dialkylamino starch and other etherified starches, methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphate crosslinked starch, dicarboxylic acid crosslinked starch and other crosslinked starch, starch polyacrylate Amide copolymer, starch polyacrylic acid copolymer, starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylic acid ester copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene Examples thereof include starch graft polymers such as maleic acid copolymer, starch polyethylene oxide copolymer, and starch polypropylene copolymer.

  Examples of natural polymer compounds that can be used as water-soluble polymer compounds include water-soluble soybean polysaccharides, starch, gelatin, hemicellulose extracted from soybeans, potato starch, potato starch, tapioca starch, wheat starch, and corn starch. Starch, Carrageenan, Laminaran, Sea Saumannan, Funari, Irish Moss, Agar, Algae, etc. , Plant mucous substances such as benzoin gum, homopolysaccharides such as dextran, glucan and levan, and microbial mucous substances such as hetropolysaccharides such as succinoglucan and santangum, glue, gelatin, casein and Proteins such as collagen is preferable.

  Among the above, starch derivatives such as gum arabic, dextrin and hydroxypropyl starch, carboxymethyl cellulose, soybean polysaccharide and the like can be preferably used.

  The content of the water-soluble polymer compound other than the star polymer is preferably 0.1 to 25.0% by mass, and more preferably 0.3 to 20.0% by mass.

In general, the plate surface treating agent of the present invention is more advantageously used in the acidic range of pH 2 to 6. In order to achieve such a pH, it is preferable to add and adjust a pH adjusting agent such as a mineral acid, an organic acid, or a salt thereof in the plate surface treatment agent.
Examples of the mineral acid include nitric acid, sulfuric acid, phosphoric acid, metaphosphoric acid, and polyphosphoric acid.
Examples of the organic acid include acetic acid, succinic acid, citric acid, malic acid, malonic acid, tartaric acid, p-toluenesulfonic acid, lactic acid, repric acid, phytic acid, and organic phosphonic acid.
Preferred salts include disodium hydrogen phosphate, dipotassium hydrogen phosphate, diammonium hydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium pyrophosphate, sodium hexametaphosphate, sodium tripolyphosphate, sodium nitrate , Potassium nitrate, ammonium nitrate, sodium sulfate and the like.
A pH adjuster may be used individually by 1 type, or may use 2 or more types together. The addition amount is preferably 0.01 to 3.0% by mass.
The plate surface treating agent of the present invention preferably contains a water-soluble polymer compound and at least one selected from phosphate and phosphoric acid.

The plate surface treating agent of the present invention preferably further contains a surfactant. Examples of the surfactant include an anionic surfactant and / or a nonionic surfactant.
Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene 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 tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates Salts, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, styrene-anhydrous Examples thereof include partially saponified products of maleic acid copolymers, partially saponified products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.
Among these, dialkyl sulfosuccinates, alkyl sulfate esters, and alkyl naphthalene sulfonates are particularly preferably used.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol mono fatty acid esters, Sugar fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene castor oil ether, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester, polyglycerin fatty acid partial ester, polyoxyethylene glycerin fatty acid partial ester , Fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, tri Ethanolamine fatty acid esters, such as trialkylamine oxides.
Among these, polyoxyethylene alkyl ethers, polyoxyethylene-polyoxypropylene block copolymers, polyoxyethylene castor oil ether, and the like are preferably used.

  Acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based anions, and nonionic surfactants can also be used in the same manner.

These surfactants can be used in combination of two or more. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable. These compounds are preferably selected and used in consideration of environmental effects.
The amount of the surfactant used is not particularly limited, but is preferably 0.01 to 20% by mass in the plate surface treating agent.

It is preferable to add an organic solvent having a boiling point of 130 ° C. or higher to the plate surface treating agent of the present invention in order to protect the oil sensitivity of the image area.
This type of organic solvent, on the other hand, functions to remove the trace amount of remaining photosensitive film adhering to the non-image area hydrophilic layer and to enhance the hydrophilicity of the non-image area.
Specific examples of the organic solvent having a boiling point of 130 ° C. or higher include alcohols such as n-hexanol, 2-ethylbutanol, n-heptanol, 2-heptanol, 3-heptanol, 2-octanol, 2-ethylhexanol, 3, 5 , 5-trimethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, cyclohexanol, benzyl alcohol, tetrahydrofurfuryl alcohol and the like.
Examples of ketones include methyl-n-amyl ketone, methyl-n-hexyl ketone, ethyl-n-butyl ketone, di-n-propyl ketone, diacetone alcohol, and cyclohexanone.
Esters include: n-amyl acetate, isoamyl acetate, methyl isoamyl acetate, methoxybutyl acetate, benzyl acetate, ethyl lactate, butyl lactate, lactate-n-amyl, methyl benzoate, ethyl benzoate and benzyl benzoate Phthalic acids such as benzoates, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate Aliphatic dibasic esters such as diesters, dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, epoxidized trig such as epoxidized soybean oil Celite ethers, tricresyl phosphate, trioctyl phosphate, phosphate esters such as tris chloroethyl phosphate, and the like.
Examples of amides include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone and the like.

Polyhydric alcohols and their derivatives include ethylene glycol, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol butyl ether, ethylene glycol dibutyl ether, ethylene glycol isoamyl ether, ethylene glycol monophenyl ether, ethylene glycol monophenyl Ether acetate, ethylene glycol benzyl ether, ethylene glycol monohexyl ether, methoxyethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether Ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol, propylene glycol, dipropylene glycol, propylene glycol monoethyl ether, propylene glycol monobutyl ether, 1 -Butoxyethoxypropanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, butylene glycol, hexylene glycol, octylene glycol, glycerin, diglycerin , It may be mentioned trimethylolpropane, glycerol monoacetate, glycerol triacetates.
Examples of the hydrocarbon type include aromatics, aliphatic compounds, squalane and the like of petroleum fractions having a boiling point of 160 ° C. or higher.

Conditions for selecting an organic solvent having a boiling point of 130 ° C. or higher include its environmental safety, particularly odor.
These solvents may be used alone or in combination of two or more.
In the plate surface treating agent of the present invention, these organic solvents may be solubilized with a surfactant to be a solution type, or emulsified and dispersed as an oil phase to be an emulsified type.

  The amount of the organic solvent having a boiling point of 130 ° C. or higher is preferably 0.1 to 5.0% by mass and more preferably 0.3 to 3.0% by mass in the plate surface treating agent.

The plate surface treating agent of the present invention may contain nitrate or sulfate.
Examples of nitrates and sulfates that can be included in the plate surface treating agent include magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium hydrogen sulfate, nickel sulfate, and the like.
It is preferable that these usage-amounts are 0.05-1.0 mass% in a plate surface treating agent.

Usually, the plate surface treatment agent is often marketed as a concentrated solution, and is used after being diluted by adding tap water, well water or the like at the time of use. Since calcium ions contained in the diluted tap water and well water adversely affect printing and may cause the printed matter to be easily stained, the plate surface treatment agent of the present invention is used to eliminate this drawback. It is preferable to contain a chelate compound.
Preferable chelate compounds include, for example, Na ₂ P ₂ O ₇ , Na ₅ P ₃ O ₃ , Na ₃ P ₃ O ₉ , Na ₂ O ₄ P (NaO ₃ P) PO ₃ Na ₂ , calgon (sodium polymetaphosphate) Such as polyphosphate, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; dihydroxyethylglycine, its potassium salt, its sodium salt; hydroxyiminodiacetic acid, its potassium salt, its sodium salt; glycol ether diamine tetraacetic acid, its Potassium salt, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetramine hexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid, potassium salt thereof, sodium salt thereof; -Diaminosi Rhohexanetetraacetic acid, its potassium salt, its sodium salt; aminopolycarboxylic acids such as 1,3-diamino-2-propanoltetraacetic acid, its potassium salt, its sodium salt, nitrilotriacetic acid, its potassium salt, its sodium 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, its sodium salt; aminotri (methylenephosphonic acid), its potassium salt, its sodium salt; ethyleneaziminetetra (methylenephosphonic acid), its potassium salt Diethylenetriaminepenta (methylenephosphonic acid), potassium salt, sodium salt thereof; organic phosphonic acids such as hexamethylenediaminetetra (methylenephosphonic acid), potassium salt, sodium salt, etc., or 2-phospho Butanetricarboxylic acid-1,2,4, potassium salt thereof, sodium salt thereof; 2 monophosphonobutanone tricarboxylic acid-2,3,4, potassium salt thereof, sodium salt thereof; 1-phosphonoethanetricarboxylic acid-1, Examples include phosphonoalkanetricarboxylic acids such as 2, 2, its potassium salt, its sodium salt and the like.
An organic amine salt is also effective in place of the sodium salt or potassium salt of the chelate compound.
These chelate compounds are selected so that they are stably present in the plate surface treating agent composition and do not impair the printability.
The addition amount of the chelate compound is preferably 0.001 to 1.0 mass% with respect to the plate surface treating agent at the time of use.

A preservative, an antifoaming agent, etc. can be further added to the plate surface treating agent of the present invention.
Examples of 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 , Quinoline, guanidine derivatives, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3-diol, 1,1-dibromo-1-nitro-2- Examples include ethanol, 1,1-dibromo-1-nitro-2-propanol, and omadins.
A preferable addition amount of the preservative is an amount that stably exerts an effect on bacteria, mold, yeast, etc., and varies depending on the type of bacteria, mold, yeast, but 0.01% in the plate surface treatment agent. The range of ˜4.0% by mass is preferable, and it is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization.
In addition, as the antifoaming agent, a general silicone-based self-emulsifying type, emulsifying type, surfactant nonionic HLB (Hydrophile-Lipophile Balance) value of 5 or less can be used. Silicone defoamers are preferred. Among them, an emulsified dispersion type and a solubilized type can be used.
The content of the antifoaming agent is preferably 0.001 to 1.0% by mass in the plate surface treating agent.

The balance of the plate surface protective agent of the present invention is preferably water.
When the plate surface protective agent of the present invention is prepared as a solution type or an emulsification type, it can be prepared according to a conventional method.
For example, for emulsification dispersion, prepare the aqueous phase at a temperature of 40 ° C ± 5 ° C, stir at high speed, slowly drop the prepared oil phase into the aqueous phase, stir well, and then prepare the emulsion through a pressure type homogenizer. Can do.

The plate surface treating agent of the present invention can be used for either a positive lithographic printing plate precursor or a negative lithographic printing plate precursor, and can be used for making a lithographic printing plate from various lithographic printing plate precursors.
The planographic printing plate precursor method may be a thermal method or a photopolymer method.

<Negative photosensitive layer>
The lithographic printing plate precursor that can be used in the present invention is not particularly limited, and contains (A) a sensitizing dye, (B) a polymerization initiator, (C) a polymerizable compound, and (D) a binder polymer. A lithographic printing plate precursor having a negative-type photosensitive layer (hereinafter also referred to as “image forming layer” or “recording layer”) is preferable.

(A) Sensitizing dye The photosensitive layer in the lithographic printing plate precursor that can be used in the invention preferably contains a sensitizing dye.
There is no restriction | limiting in particular as a sensitizing dye which can be used for this invention, A well-known sensitizing dye can be used.
For example, by adding a sensitizing dye having a maximum absorption at 300 to 450 nm, a sensitizing dye having a maximum absorption at 500 to 600 nm, and a sensitizing dye having a maximum absorption at 750 to 1,400 nm, Can provide a high-sensitivity lithographic printing plate precursor corresponding to a 405 nm violet laser, a 532 nm green laser, and an 830 nm IR laser that are usually used in the above.

The sensitizing dye having a maximum absorption at 750 to 1,400 nm that is preferably used in the present invention will be described in detail.
In the present invention, the “sensitizing dye having maximum absorption at 750 to 1,400 nm” is also referred to as “infrared absorber”.
The infrared absorber is preferably a dye or pigment having an absorption maximum at a wavelength of 750 to 1,400 nm.

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.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes.
Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following formula (a).

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —N (R ⁹ ) (R ¹⁰ ), —X ² -L ¹ or a group shown below. Here, R ⁹ and R ¹⁰ may be the same or different, and may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. Represents a hydrogen atom, and R ⁹ and R ¹⁰ may be bonded to each other to form a ring. Of these, a phenyl group is preferred. X ² represents an oxygen 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 hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. . In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. In the group shown below, Xa ^- has Za described later ^- is defined as for, 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 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 It is also preferable to form a 6-membered ring.

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.
Further, Z _a ^- represents a counter anion. However, when the cyanine dye represented by formula (a) has an anionic substituent in the structure thereof, Z _a is does not require charge neutralization ^- is not necessary. Preferred Z _a ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably perchloric acid, in view of the storage stability of the photosensitive layer coating solution. Ions, hexafluorophosphate ions, and aryl sulfonate ions.
It is particularly preferable that the counter ion does not contain a halide ion.

These infrared absorbers may be added to the same layer as other components, or another layer may be provided and added thereto.
The content of these infrared absorbers in the photosensitive layer is 0.01 to 50% by mass with respect to the total solid content constituting the photosensitive layer from the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer. It is preferably 0.1 to 10% by mass, more preferably 0.5 to 10% by mass.

  Other infrared absorbers include paragraph numbers 0012 to 0038 of JP-A No. 2002-40638, paragraph numbers 0144 to 0174 of JP-A No. 2004-250158, paragraph numbers 0219 to 0249 of JP-A No. 2005-47947, and JP-A No. 2005. -91617 paragraph number 0231 to 0260, JP 2005-91618 paragraph number 0219 to 0249, JP 2005-134893 paragraph number 0195 to 0224, JP 2005-250158 paragraph number 0144 to 0173, No. 2005-250438, paragraph numbers 0192-0201, JP-A-2005-257949, paragraph numbers 0241-0273, JP-A-2005-298567, paragraph numbers 0235-0268, JP-A-2005-300650, paragraph numbers 0243-0276 , JP 2 Paragraph Nos. 0177 to 0186 of No. 05-300217, Paragraph Nos. 0215 to 0224 of JP-A No. 2006-267289, Paragraph Nos. 0107 to 0124 of JP-A No. 2007-17948, Paragraph Nos. 0275 to 0304 of JP-A No. 2007-47742, Paragraph Nos. 0188 to 0206 in JP 2007-248863, Paragraphs 0114 to 0125 in JP 2007-249036, Paragraphs 0115 to 0123 in JP 2007-249037, Paragraphs 0115 to JP 2008-242093 The ones described in JP-A-2008-249851, paragraphs [0040] to [0061] can be preferably used.

  Next, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described. Examples of such a sensitizing dye include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, and the like.

  Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following formula (IX).

In 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 NR ₃ .
R ₁ , R ₂ and R ₃ each independently represents a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be formed.

R ₁ , R ₂ and R ₃ each independently represents a monovalent non-metallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, It represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, or a halogen atom.

  Next, A in Formula (IX) represents an aromatic ring group or a heterocyclic group which may have a substituent.

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

  Furthermore, paragraph numbers 0168-0218 of JP-A-2005-47947, paragraph numbers 0180-0230 of JP-A-2005-91617, paragraph numbers 0168 of JP-A-2005-91618] to 0218, paragraphs of JP-A-2005-134893. Nos. 0144 to 0194, paragraph numbers 0192 to 0242 of JP 2005-250158, paragraph numbers 0202 to 0250 of JP 2005-250438, paragraph numbers 0190 to 0240 of JP 2005-257949, JP 2005-298567. Paragraph numbers 0184 to 0234, paragraph numbers 0192 to 0242 of JP-A-2005-300650, paragraph numbers 0170 to 0176 of JP-A-2005-300817, paragraph numbers 0225 to 0273 of JP-A 2006-267289, JP-A 2007- No. 17948 Paragraph Nos. 0058 to 0084, Paragraph Nos. 0230 to 0274 of JP 2007-47742, Paragraph Nos. 0207 to 0246 of JP 2007-248863, Paragraph Nos. 0076 to 0113 of JP 2007-249036, JP 2007-249037 Paragraph numbers 0078 to 0114, paragraph numbers 0033 to 0038 of JP 2007-171406, paragraph numbers 0023 to 0059 of JP 2007-206216, paragraph numbers 0016 to 0043 of JP 2007-225701, JP 2007 The sensitizing dyes described in Paragraph Nos. 0037 to 0049 of No. 316582, Paragraph Nos. 0026 to 0115 of JP-A-2007-328243, and Paragraph Nos. 0067 to 0114 of JP-A-2008-242903 can also be preferably used.

(B) Polymerization initiator The photosensitive layer in the lithographic printing plate precursor that can be used in the invention preferably contains a polymerization initiator (hereinafter also referred to as “initiator compound”).

As the initiator compound in the present invention, those known to 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, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, An iron arene complex is mentioned.
Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds and metallocene compounds is preferred, and at least one selected from the group consisting of hexaarylbiimidazole compounds and onium salts. Particularly preferred is a seed.
Two or more of the above polymerization initiators can be used in combination as appropriate.

Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B Nos. 45-37377 and 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 ′ -Tetraphenylbiimidazole 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 300 to 450 nm.

  The onium salt suitably used in the present invention is an onium salt represented by the following formulas (RI-I) to (RI-III).

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

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

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

  Examples of other polymerization initiators include paragraph numbers 0065 to 0124 of JP-A No. 2004-317652, paragraph numbers of 0202 to 0264 of JP-A No. 2005-47947, paragraph numbers of 0091 to 0164 of JP-A No. 2005-91618, and JP-A No. 2005. Paragraph Nos. 0031 to 0104 of JP-A-134893, Paragraph Nos. 0103 to 0140 of JP-A-2005-250158, Paragraph Nos. 0115 to 0189 of 2005-300650, Paragraph Nos. 0120 to 0209 of JP-A 2006-267289, JP-A 2007 Paragraph Nos. 0051 to 0054 of No. 17948, Paragraph Nos. 0190 to 0227 of JP 2007-47742, Paragraph Nos. 011 to 0185 of JP 2007-248863, Paragraph Nos. 0037 to 0062 of JP 2007-249036, Special Open 2007 Paragraph Nos. 0038 to 0063 of No. 249037, Paragraph Nos. 0039 to 0047 of JP 2007-171406, Paragraph Nos. 0060 to 0115 of JP 2007-206216, Paragraph Nos. 0071 to 0126 of JP 2007-206217, JP Those described in JP-A-2008-316582, paragraph numbers 0050 to 0059, JP-A-2008-242893, paragraphs 0042 to 0066, and JP-A-2008-276167, paragraphs 0016 to 0054 can be preferably used.

The polymerization initiator in the present invention is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. Preferably, it is 1.0-10 mass%.

(C) Polymerizable compound The photosensitive layer in the lithographic printing plate precursor that can be used in the present invention preferably contains a polymerizable compound.
The polymerizable compound that can be used in the photosensitive layer in the present invention is a compound having at least one ethylenically unsaturated bond, and is selected from compounds having at least one terminal ethylenically unsaturated bond, preferably two or more. It is. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. Such a compound group is widely known in the industrial field, and in the present invention, these can be used without any particular limitation.
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 an alcohol compound and an amide of an unsaturated carboxylic acid and an amine compound are used.
Further, addition reaction products of unsaturated carboxylic acid esters or amides having a nucleophilic substituent such as hydroxyl group, amino group, mercapto group and the like with monofunctional or polyfunctional isocyanates or epoxies, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used.
Further, an addition reaction product of an isocyanate group, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group, and a monofunctional or polyfunctional alcohol, amine or thiol, further a halogeno group or A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy 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.

  Examples of the esters include 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.

  Examples of amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  Also suitable are urethane-based addition-polymerizable compounds produced by the addition reaction of isocyanate and hydroxyl groups. Specific examples thereof include, for example, vinyl urethane described in JP-B-48-41708. Compounds and the like.

Also, 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- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable.
Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates.
Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like Can also be mentioned.
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.

The polymerizable compounds in the photosensitive layer may be used alone or in combination of two or more.
The content of the polymerizable compound in the photosensitive layer is preferably 5 to 75% by mass, more preferably 25 to 70% by mass, and more preferably 30 to 60% by mass with respect to the total solid content of the photosensitive layer. More preferably.

(D) Binder polymer The photosensitive layer in the lithographic printing plate precursor that can be used in the present invention preferably contains a binder polymer. The chemical structure of the binder polymer that can be used in the present invention is not particularly limited, but is preferably an organic polymer having an acid group from the viewpoint of solubility in an alkaline processing liquid, that is, developability, and particularly a carboxylic acid or a salt thereof. The organic polymer to contain is more preferable.

Examples of the binder polymer that can be used in the present invention include carboxylic acid-containing alkaline water-soluble or swellable organic polymers.
Examples of such an organic polymer include addition polymers having a carboxylic acid group in the side chain, such as JP-B-59-44615, JP-B-54-34327, JP-B-58-12777, and JP-B-54-25957. JP-A-54-92723, JP-A-59-53836, JP-A-59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid Copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers and the like are useful.
As the binder polymer, a copolymer containing a monomer unit derived from a (meth) acrylic acid ester containing a carboxylic acid (salt) group is preferable.
Also useful are acidic cellulose derivatives having a carboxylic acid group in the side chain, and those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group.
Furthermore, Japanese Patent Publication No. 7-120040, Japanese Patent Publication No. 7-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Publication No. 63-287944, Japanese Patent Publication No. 63-287947, Japanese Patent Publication No. Hei 1 Polyurethane resins described in JP-A Nos. 271741 and 11-352691 are also useful as alkaline water-soluble or swellable binders.
As the binder polymer that can be used in the present invention, an acrylic resin, a methacrylic resin, or a urethane resin is preferably used.

  An example of a material suitable as the binder polymer that can be used in the present invention is a copolymer having (a) a monomer unit containing a carboxylic acid group (including a salt thereof) and (b) a monomer unit imparting radical crosslinkability. It is a polymer.

(A) Although it does not specifically limit as a monomer unit containing a carboxylic acid group, The structure of paragraph number 0059-0075 of Unexamined-Japanese-Patent No. 2002-40652 and Unexamined-Japanese-Patent No. 2005-300650 is used preferably.
(B) Although it does not specifically limit as a monomer unit which provides radical crosslinkability, The structure of Paragraph Nos. 0041-0053 of Unexamined-Japanese-Patent No. 2007-248863 is used preferably.

The binder polymer that can be used in the present invention includes a monomer unit derived from an ethylenically unsaturated compound that does not include (a) a monomer unit containing a carboxylic acid group and (b) a monomer unit imparting radical crosslinkability. You may have as a polymerization component.
As such a monomer unit, a monomer unit derived from (meth) acrylic acid ester or (meth) acrylic acid amide is preferable. In particular, monomer units derived from the amide group (meth) acrylic acid amides described in paragraph numbers 0061 to 0084 of JP-A-2007-272134 are preferably used.
The content of this monomer is preferably 5 to 50 units, more preferably 5 to 35 units, even more preferably 5 to 25 units, when the total number of monomer units is 100. .

In the photosensitive layer according to the invention, a urethane resin having a crosslinkable group in the side chain can be used as the binder polymer in addition to the addition polymer having the above-mentioned combination of monomer units.
Here, the crosslinkable group is a group capable of crosslinking the binder polymer by a chemical reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. The chemical structure is not particularly limited as long as it has such a function. For example, an ethylenically unsaturated group is preferable as a functional group capable of addition polymerization.
Moreover, the functional group described in Paragraph Nos. 0130 to 0139 of Unexamined-Japanese-Patent No. 2007-17948 can be illustrated.

  The polyurethane resin having a crosslinkable group in the side chain particularly preferably used in the present invention comprises (i) a diisocyanate compound, (ii) a diol compound having a carboxyl group, (iii) a diisocyanate compound having a crosslinkable group, and If present, it can be obtained by polyaddition reaction of (iv) a diol compound having no carboxyl group and (v) a compound having an amino group.

Examples of the compounds (i), (ii) and (iii) include formulas (4) to (10) and specific examples described in paragraph numbers 0142 to 0167 of JP-A No. 2007-17948.
The compound of (iv) includes general formula (A ′), formulas (a) to (e), formulas (11) to (22), and specific examples described in paragraph numbers 0180 to 0225 of JP-A No. 2007-17948. Specific compounds.
Examples of the compound (v) include formula (31) and formula (32) and specific compounds described in paragraph numbers 0227 to 0230 of JP-A No. 2007-17948.
In addition to the above polyurethane resin, a polyurethane resin obtained by introducing a crosslinkable group into a polyurethane having a carboxyl group as described in JP-A-2003-270775 by a polymer reaction can also be exemplified.

  In order to maintain the developability of the photosensitive layer, the binder polymer used preferably has an appropriate molecular weight, and the mass average molar mass (Mw) is more preferably 5,000 to 300,000, More preferably, it is 20,000-150,000.

  These binder polymers can be contained in an arbitrary amount in the photosensitive layer, and the content of the binder polymer in the photosensitive layer is preferably 10 to 90% by mass, and 30 to 80% by mass. More preferably.

(E) Other photosensitive layer components The photosensitive layer in the lithographic printing plate precursor that can be used in the present invention may further contain various additives as required.
Additives include surfactants for improving developability and improving the surface of the coating, hydrophilic polymers for improving developability and improving the dispersion stability of microcapsules, and visual and non-image areas. A colorant and a print-out agent, a polymerization inhibitor for preventing unnecessary thermal polymerization of a radically polymerizable compound during production or storage of the photosensitive layer, a higher fat derivative for preventing polymerization inhibition by oxygen, Add inorganic fine particles to improve the cured film strength of the image area, hydrophilic low molecular weight compounds to improve developability, co-sensitizers and chain transfer agents to improve sensitivity, plasticizers to improve plasticity, etc. be able to.
Any of these compounds can be used, for example, JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, The compounds described in JP-A 2007-316582 and JP-A 2007-328243 can be used.

<Acid cross-linked layer>
As one of the thermal negative type photosensitive layers, an acid-crosslinked photosensitive layer (acid-crosslinked layer) is also preferably exemplified. The acid-crosslinking layer comprises a photothermal conversion substance, a thermal acid generator, a compound that crosslinks with an acid that is a curable compound (crosslinking agent), and an alkali-soluble polymer compound that can react with the crosslinking agent in the presence of an acid. contains.
In the acid cross-linking layer, infrared light absorbed by the photothermal conversion substance is converted into heat, the heat acid generator is decomposed by this heat to generate an acid, and the generated acid reacts with the cross-linking agent and the alkali-soluble polymer compound. And harden.
Specifically, for example, photosensitive layers described in JP-A-7-306528, JP-A-8-276558, JP-A-10-123701, and JP-A-10-203037 are preferably used.

<Positive photosensitive layer>
A positive type (positive type) photosensitive composition contains an alkali-soluble polymer compound and a photothermal conversion substance.
In the positive type photosensitive layer, the photothermal conversion substance converts light energy such as an infrared laser into heat, and the heat efficiently cancels the interaction that reduces the alkali solubility of the alkali-soluble polymer compound.
Specifically, JP-A-11-218914, JP-A-2001-215893, JP-A-2001-305722, JP-A-2002-311570, JP-A-2002-3233769, JP-A-2007-122003, JP-A-2008. JP-A-64778, JP-A-2008-64959, JP-A-2008-76516, JP-A-2008-76996, JP-A-2008-197566, JP-A-2008-209774, JP-A-2008-224991, JP-A-2008-. The photosensitive layer described in each publication of No. 233496 is preferably used.

<Formation of photosensitive layer>
The photosensitive layer in the lithographic printing plate precursor that can be used in the present invention can be formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. As the solvent used here, the compounds described in paragraph No. 0159 of JP-A-2007-249037 are preferably used, and these solvents are used alone or in combination.
The solid concentration of the coating solution is preferably 1 to 50% by mass.
Moreover, although the photosensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is preferably 0.3 to 3.0 g / m ² . Within the above range, good sensitivity and good film properties of the photosensitive layer can be obtained.

<Protective layer>
The lithographic printing plate precursor that can be used in the present invention is provided with a protective layer on the photosensitive layer, if necessary, to prevent the occurrence of scratches in the photosensitive layer, to block oxygen, and to prevent ablation during high-intensity laser exposure. May be.
In the present invention, the exposure is usually carried out in the atmosphere, but the protective layer is a photosensitive layer of a low-molecular compound such as oxygen or a basic substance that exists in the atmosphere that inhibits the image forming reaction caused by exposure in the photosensitive layer. Inhibition of image formation reaction due to exposure in the air is prevented.
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 photosensitive layer, and It is preferable that it can be easily removed in the development processing step 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.
Moreover, as a protective layer, the protective layer described in paragraph number 0200-0261 of Unexamined-Japanese-Patent No. 2008-15503 and Unexamined-Japanese-Patent No. 2008-39813 can be used suitably.

<Support>
The support that can be used for the lithographic printing plate precursor is not particularly limited as long as it is a dimensionally stable plate-like support, but is preferably a hydrophilic support, and more preferably an aluminum plate. .
For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which the metal is laminated or deposited. A preferable support includes a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.
Specific examples of the aluminum support and the treatment method include preferably the aluminum support and the treatment method described in JP-A-2005-88300.

Further, in the present invention, high-strength aluminum can be suitably used, and specifically, those described in JP-A-2008-291305 can be suitably used.
The support that can be used for the lithographic printing plate precursor is preferably subjected to a surface roughening treatment.
For the roughening treatment of the support, methods described in JP-A-2005-88300 and the like can be referred to.
Further, the support that can be used for the lithographic printing plate precursor is preferably a support that has been subjected to an electrochemical surface roughening treatment with an aqueous hydrochloric acid solution. More preferably, the support is subjected to a roughening treatment and an electrochemical roughening treatment with an aqueous hydrochloric acid solution.
In the case of the above embodiment, when the plate surface treating agent of the present invention is used, the anti-staining property of the non-image area is more excellent.
The average opening diameter of the small pits in the support subjected to electrochemical surface roughening with an aqueous hydrochloric acid solution is preferably 0.05 to 0.8 μm, and more preferably 0.1 to 0.6 μm.
The average opening diameter of small pits is calculated by the measurement method described in JP-A-2006-272745, paragraph numbers 0029 to 0036.

<Undercoat layer>
The lithographic printing plate precursor according to the invention may be provided with an undercoat layer (also referred to as an “intermediate layer”) for the purpose of improving the adhesion and soiling between the photosensitive layer and the support.
Specific examples of such an undercoat layer (intermediate layer) include JP-B-50-7481, JP-A-54-72104, JP-A-59-101651, JP-A-60-149491, and JP-A-60. -232998, JP-A-3-56177, JP-A-4-282637, JP-A-5-16558, JP-A-5-246171, JP-A-7-159983, JP-A-7-314937, JP-A-8- 202025, JP-A-8-320551, JP-A-9-34104, JP-A-9-236911, JP-A-9-269593, JP-A-10-69092, JP-A-10-115931, JP-A-10-161317 JP-A-10-260536, JP-A-10-282682, JP-A-11-84684, JP-A-11-38635, JP-A-11-38 29, JP-A-10-282645, JP-A-10-301262, JP-A-11-24277, JP-A-11-109641, JP-A-10-319600, JP-A-11-327152, JP-A-2000-10292 And JP-A-2000-235254, JP-A-2000-352824, and JP-A-2001-209170.

In the lithographic printing plate precursor, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. The undercoat layer using a compound containing a polymerizable group enhances the adhesion between the support and the photosensitive layer in the exposed area, and easily peels off the photosensitive layer from the support in the unexposed area. Therefore, developability is improved.
As an undercoat layer using a compound containing a polymerizable group, specifically, a silane cup having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679. Preferable examples include a ring agent and a phosphorus compound having an ethylenic double bond reactive group described in JP-A-2-304441.
Particularly preferred compounds include compounds having a polymerizable group such as a methacryl group and an allyl group and a support-adsorptive group such as a sulfonic acid group, a phosphoric acid group and a phosphoric acid ester.
A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.

The undercoat layer preferably also contains a resin having a phosphate group and / or a phosphonic acid group. In particular, a resin having a phosphonic acid group is preferably included, and an undercoat layer formed by treatment with the polyvinylphosphonic acid mentioned in the hydrophilization treatment of the support is preferably used. In particular, a resin having the following structure is preferably used.
In addition, the ratio of each monomer unit described in the following chemical structural formula is a molar ratio.

The coating amount (solid content) of the undercoat layer is preferably 0.1-100 mg / m ^2, more preferably 1 to 30 mg / m ^2.

<Back coat layer>
After the surface treatment is performed on the support or after the undercoat layer is formed, a backcoat layer can be provided on the back surface of the support, if necessary.
Examples of the back coat layer include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organic metal compounds or inorganic metal compounds described in JP-A-6-35174, and the like. Preferable examples include a coating layer made of a metal oxide. 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.

[Processing for planographic printing plates]
The processing method of the lithographic printing plate of the present invention is not particularly limited as long as it is a method using the lithographic printing plate surface treatment agent of the present invention, but the step of image exposure of the lithographic printing plate precursor (hereinafter referred to as “exposure step”). ), A step of developing with a processing solution (hereinafter also referred to as “developing step”), and a step of performing plate surface treatment using the lithographic printing plate surface treatment agent of the present invention (hereinafter referred to as “plate surface treatment”). It is preferable that the method includes a step.

<Exposure process and development process>
Here, the development processing means that a non-exposed portion of the photosensitive layer is removed with a developer to form an image corresponding to the exposed portion.

In the present invention, in the plate making process for producing a lithographic printing plate from a lithographic printing plate precursor, the entire surface of the lithographic printing plate precursor may be heated before exposure, during exposure, and between exposure and development, as necessary. . Such heating promotes the image forming reaction in the photosensitive layer, and provides the advantages of improved sensitivity, improved printing durability, and stabilized sensitivity.
Further, for the purpose of improving the image strength and printing durability, it is also effective to post-heat the image obtained by development or to expose the entire surface. Usually, heating before development is preferably performed under mild conditions of 150 ° C. or less. Stronger conditions are used for heating after development. A temperature range of 200-500 ° C is preferred.

As the lithographic printing plate precursor that can be used in the processing method of the lithographic printing plate of the present invention, those described above can be suitably used.
The lithographic printing plate precursor that can be used in the present invention is preferably a lithographic printing plate precursor that can be recorded with a laser such as a visible light laser or an infrared laser.
Thermal recording with an ultraviolet lamp or a thermal head is also possible.
The exposure light source that can be used in the present invention can be appropriately selected according to the mode of the photosensitive layer, but a visible light laser having a wavelength of 350 nm to 450 nm, a solid-state laser and a semiconductor laser emitting infrared light having a wavelength of 760 nm to 1,200 nm. It is preferable that the lithographic printing plate precursor is image-exposed.

  The lithographic printing plate precursor that can be used in the present invention is preferably developed with water or an alkaline aqueous solution after exposure.

As a developer and a replenisher for a lithographic printing plate precursor, a conventionally known alkaline aqueous solution can be used. Examples of the alkaline agent include sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, carbonic acid. Examples thereof include inorganic alkali salts such as sodium hydrogen, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium.
Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine can also be used.
These alkaline agents can be used alone or in combination of two or more.
The pH of the developer or replenisher is preferably 14 or less, more preferably 8 to 13, and still more preferably 11 to 13.

Furthermore, when developing using an automatic developing machine, the developer in the developing tank can be developed for a long time by adding the same developer solution or an aqueous solution (replenisher solution) having a higher alkali strength than the developer solution to the developer solution. It is known that a large amount of a lithographic printing plate precursor can be processed without changing the liquid.
This replenishment method is also preferably applied in the present invention.

Various surfactants, organic solvents, and the like can be added to the developer and the replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving the ink affinity of the printing plate image area.
Examples of the surfactant include anionic, cationic, nonionic and amphoteric surfactants.
Preferred organic solvents include benzyl alcohol.
Further, addition of polyethylene glycol or a derivative thereof, or polypropylene glycol or a derivative thereof is also preferable.
In addition, non-reducing sugars such as arabit, sorbit and mannitol can be added.

  Further, in the developer and replenisher, if necessary, inorganic salt-based reducing agents such as hydroquinone, resorcin, sulfite or sodium bisulfite, and organic carboxylic acid, antifoaming agent, water softener Can also be added.

<Plate surface treatment process>
The processing method for a lithographic printing plate of the present invention includes a step of performing a plate surface treatment using the lithographic printing plate surface treatment agent of the present invention.
Although the usage aspect of the plate surface treating agent of this invention is not restrict | limited in particular, when an automatic gum applicator etc. are used, it can apply | coat uniformly and is preferable.
The treatment with the plate surface treating agent of the present invention can be carried out immediately after the development step by anhydrous washing, or after the development treatment (including a washing step, washing with circulating water or a small amount of applied washing with water) or containing a surfactant. It can also be carried out after treatment with a rinsing solution.

The plate surface treatment with the plate surface treating agent of the present invention is also suitably performed using an automatic developing machine.
This automatic processor generally comprises a developing unit and a post-processing unit, and includes a device for transporting a lithographic printing plate precursor, each processing solution tank and a spray device, and transports the exposed lithographic printing plate precursor horizontally. However, each processing liquid pumped up by the pump is sprayed from the spray nozzle to develop and post-process.
In addition, a method of immersing and transporting in a processing liquid tank filled with the processing liquid by a guide roll in the liquid and developing processing, or supplying a small amount of rinsing water after development to the plate surface and rinsing the waste water A method of reusing as a diluting water for a developer stock solution is also known.
In such automatic processing, processing can be performed while each replenisher is replenished with each replenisher according to the processing amount, operating time, and the like.
In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can be applied.
The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the polymer compound, the molecular weight is a mass average molar mass (Mw), and the ratio of repeating units is a mole percentage, except for those specifically defined.

[Examples 1-27 and Comparative Examples 1-2]

(Production of support)
0.30 mm thick aluminum plate (Si: 0.09 mass%, Fe: 0.30 mass%, Cu: 0.013 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn : 0.001% by mass, Ti: 0.027% by mass, the balance being aluminum and an inevitable impurity aluminum alloy), the following various surface treatments (a) to (k) were continuously performed.
In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) Mechanical surface roughening treatment While supplying a suspension of a polishing agent (pumice) having a specific gravity of 1.12 and water as a polishing slurry liquid to the surface of the aluminum plate, mechanical roughening is performed by a rotating nylon brush. Surface treatment was performed.
The average particle size of the abrasive was 30 μm, and the maximum particle size was 100 μm.
The material of the nylon brush was 6 · 10 nylon, the hair length was 45 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm.
Three rotating brushes were used. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6% by mass, an aluminum ion concentration of 6.5% by mass and a temperature of 70 ° C. / M ² dissolved. Then, water washing by spraying was performed.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut treatment was a waste liquid from a process of performing an electrochemical surface roughening treatment using alternating current in a nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 50 ° C. The AC power supply uses electrochemical trapping with carbon electrode as the counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1. It was. Ferrite was used for the auxiliary anode.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Then, water washing by spraying was performed.

(E) Alkali etching treatment The aluminum plate was subjected to etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass to dissolve the aluminum plate by 0.50 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used in the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in the nitric acid aqueous solution.

(G) Electrochemical roughening treatment An electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 5.0 g / L aqueous solution (containing 5 g / L of aluminum ions) at a temperature of 35 ° C. The waveform of the AC power supply is electrochemically roughened using a trapezoidal trapezoidal wave AC with a time TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal trapezoidal wave AC. Processed. Ferrite was used for the auxiliary anode. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Then, water washing by spraying was performed.

(H) Alkali etching treatment The aluminum plate was subjected to etching treatment at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass%, and the aluminum plate was dissolved at 0.10 g / m ² . Removes the smut component mainly composed of aluminum hydroxide that was generated when electrochemical roughening treatment was performed using the alternating current of the previous stage, and also melted the edge part of the generated pit to smooth the edge part. did. Then, water washing by spraying was performed.

(I) Desmutting treatment A desmutting treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(J) Anodizing treatment Anodizing treatment is carried out using an anodizing apparatus (first and second electrolysis section length 6 m, first and second feeding section length 3 m each, first and second feeding electrode section length 2.4 m each). went. Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 50 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 20 ° C. Then, water washing by spraying was performed.

(K) Alkali metal silicate treatment The aluminum support obtained by anodizing treatment was immersed in a treatment tank of a 1% by mass aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silica. Acid salt treatment (silicate treatment) was performed. Thereafter, washing with water using well water was performed to obtain a support subjected to a surface silicate hydrophilization treatment.

  When the aluminum plate which performed all the said (a)-(k) process was made into the support body S-1, the centerline average roughness (Ra display by JISB0601) of each support body was measured using the needle | hook of 2 micrometers in diameter. The support S-1 was 0.50 μm.

Next, the following undercoat layer coating solution (A) was applied onto the aluminum support S-1 subjected to the above surface treatment so that the dry coating amount was 10 mg / m ² and dried.

<Undercoat layer coating solution (A)>
Polyvinylphosphonic acid (Mw 20000) 0.017 parts by mass Methanol 9.00 parts by mass Water 1.00 parts by mass

[Formation of photosensitive layer]
The following photosensitive layer coating solution (A) was prepared and applied on the undercoat layer formed as described above using a wire bar to form a photosensitive layer. Drying was performed at 125 ° C. for 34 seconds using a warm air dryer. The coating amount after drying was 1.4 g / m ² .

<Coating solution for photosensitive layer (A)>
Infrared absorber (IR-1) 0.038 parts by mass Polymerization initiator A (S-1) 0.061 parts by mass Polymerization initiator B (I-1) 0.094 parts by mass Mercapto compound (E- 1) 0.015 part by mass-Ethylenically unsaturated compound (M-1) 0.425 part by mass (trade name: A-BPE-4, Shin-Nakamura Chemical Co., Ltd.)
-Binder polymer A (B-1) (Mw: 110,000) 0.311 parts by mass-Binder polymer B (B-2) (Mw: 100,000) 0.250 parts by mass-Binder polymer C (B-3) ( Mw: 120,000) 0.062 parts by mass Additive (T-1) 0.079 parts by mass Polymerization inhibitor (Q-1) 0.0012 parts by mass Ethyl violet (EV-1) 0.021 parts by mass Fluorine-based surfactant 0.0081 parts by mass (Megafac F-780-F DIC Corporation)
Methyl isobutyl ketone (MIBK) 30% by mass solution)
・ Methyl ethyl ketone 5.886 mass parts ・ Methanol 2.733 mass parts ・ 1-methoxy-2-propanol 5.886 mass parts

In addition, the infrared absorber (IR-1), the polymerization initiator A (S-1), the polymerization initiator B (I-1), and the mercapto compound (E-1) used for the photosensitive layer coating solution (A). ), Ethylenically unsaturated compound (M-1), binder polymer A (B-1), binder polymer B (B-2), binder polymer C (B-3), additive (T-1), polymerization prohibited The structures of the agent (Q-1) and ethyl violet (EV-1) are shown below.
In the following, Me represents a methyl group, and the ratio of each monomer unit of the binder polymers A to C below is a molar ratio.

(Formation of lower protective layer)
On the formed photosensitive layer, synthetic mica (Somasif MEB-3L, 3.2 mass% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (Goselan CKS-50, saponification degree 99 mol%, polymerization degree) 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), surfactant A (manufactured by Nippon Emulsion Co., Ltd., Emalex 710), and surfactant B (Adeka Pluronic P-84: (stock) ) (Made by ADEKA) was applied with a wire bar and dried at 125 ° C. for 30 seconds with a hot air dryer.
The content ratio of synthetic mica (solid content) / polyvinyl alcohol / surfactant A / surfactant B in the coating solution for forming the lower protective layer is 7.5 / 89/2 / 1.5 (mass%). The coating amount (the coating amount after drying) was 0.5 g / m ² .

[Formation of upper protective layer]
On the lower protective layer, an organic filler (Art Pearl J-7P, manufactured by Negami Industrial Co., Ltd.), synthetic mica (Somasif MEB-3L, 3.2 mass% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.), polyvinyl alcohol (L-3266: Saponification degree 87 mol%, polymerization degree 300, sulfonic acid-modified polyvinyl alcohol, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), thickener (Serogen FS-B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) A mixed aqueous solution of surfactant (manufactured by Nippon Emulsion Co., Ltd., Emalex 710) is applied with a wire bar and dried at 125 ° C. for 30 seconds with a hot air dryer. I let you.
The content ratio of the organic filler / synthetic mica (solid content) / polyvinyl alcohol / thickener / surfactant in the coating solution for forming the upper protective layer is 3.2 / 2.0 / 80.5 / 11.5. /2.8 (mass%), and the coating amount (the coating amount after drying) was 1.76 g / m ² .

[Formation of back coat layer]
A backcoat layer similar to that of Example 1 of JP-A-6-35174 is provided on the surface of the aluminum support S-1 opposite to the side on which the photosensitive layer and the protective layer are provided, and a negative lithographic printing plate precursor (1 )

[Plate making method]
The obtained lithographic printing plate precursor was processed in the order of each step of exposure, development processing, and plate surface processing.
Light source (setter) used for exposure: Image-like exposure was performed with an infrared semiconductor laser (Trendsetter 3244VX manufactured by Creo) equipped with a water-cooled 40W infrared semiconductor laser, with an output of 9 W, an outer drum rotation speed of 210 rpm, and a resolution of 2,400 dpi. It was. As the exposure image, an image in which drawn thin lines having a width of 5 to 100 μm (5 μm intervals) were arranged as the drawn thin line evaluation image was used. For printing durability evaluation, an image capable of solid printing durability evaluation was used.
After the exposure, pre-water washing treatment, development, water washing, and plate surface treatment for removing the overcoat layer were performed using Fujifilm Corporation automatic developing machine LP1310News. As the developer, a 1: 4 water diluted solution of a developer HN-D (former product name: DH-N) manufactured by FUJIFILM Corporation was used. The pH of the developer was 12, and the temperature of the developer bath was 30 ° C.

  In the plate surface processing, the following plate surface processing agent A was used to carry out image portion protection.

<Plate surface treatment agent A>
Water 746.8 parts by mass Hydroxypropylated starch (manufactured by Nissho Chemical Co., Ltd.) 197.6 parts by mass Liso gum (manufactured by IRANEX) 33.4 parts by mass Arabic gum (Mw: 200,000) 61.4 Parts by mass, ethylenediaminetetraacetate disodium salt 2.5 parts by mass, Lapisol A-80 (manufactured by NOF Corporation) 2.7 parts by mass, phosphoric acid (85% by mass) 6.1 parts by mass, primary phosphoric acid 1.7 parts by weight of ammonium, 1.7 parts by weight of sodium hydroxide, 1.7 parts by weight of eleminol MON2 (manufactured by Sanyo Chemical Co., Ltd.) 7.5 parts by weight, 11.1 parts by weight of propylene glycol, Pionine D-1420 (Takemoto Yushi Co., Ltd.) 9.6 parts by mass · benzyl alcohol 18.4 parts by mass · Star polymer 7.0 parts by mass listed in Table 10

[Evaluation]
<Non-image area dirt prevention evaluation (stop dirt prevention evaluation)>
The lithographic printing plate precursor was forcibly aged at 60 ° C. for 4 days, then exposed and developed by the above plate making method, and treated with the plate surface treating agent A to obtain a lithographic printing plate.
This is applied to a printing press (2N-600, manufactured by Tohama Seiki Co., Ltd.), and is used with paper, ink (Soyby Red, manufactured by The Inktec Co., Ltd.), and dampening water (Alky, manufactured by Toyo Ink Co., Ltd.). Was printed.
When 50,000 sheets of printing paper used for this printing were printed, the printing machine was temporarily stopped, left for 5 hours, printing was restarted, and another 200 sheets were printed. The number of sheets until the ink completely disappeared from the non-image area was evaluated. It can be said that the smaller the number of sheets, the smaller the amount of lost paper from the restart of printing, and the better.

  The evaluation results of the planographic printing plates obtained in Examples 1-27 and Comparative Examples 1-2 are shown in Table 10 below.

  From Table 10, it can be seen that the occurrence of smearing in the non-image area after resuming printing is improved by the plate surface treating agent using the star polymer of the present invention and the processing method of the lithographic printing plate of the present invention.

[Examples 28 to 54 and Comparative Examples 3 to 4]
In the formation of the undercoat layer, using a subbing layer coating solution having the following a (B), except that a dry coating amount was set to 1.5 mg / m ^2, Examples 1-27, and Comparative Examples 1-2 The negative lithographic printing plate precursor (2) of Examples 28 to 54 and Comparative Examples 3 to 4, preparation of the lithographic printing plate, and evaluation of the obtained lithographic printing plate in the same manner as described in 1) Went to each.
The plate surface treatment was carried out by changing the star polymer of the plate surface treating agent A to the star polymer described in Table 11 below. The results are shown in Table 11.

<Undercoat layer coating solution (B)>
-0.3 parts by weight of the following polymer-60.0 parts by weight of pure water-939.7 parts by weight of methanol

  From Table 11, it can be seen that the occurrence of smudges in the non-image area after resuming printing is improved by the plate surface treating agent of the present invention and the processing method of the lithographic printing plate of the present invention.

[Examples 55-68 and Comparative Examples 5-6]

[Formation of photosensitive layer]
A photosensitive layer coating solution (B) having the following composition was bar-coated on the support S-1 and then oven-dried at 90 ° C. for 60 seconds, and used in Examples 55 to 68 and Comparative Examples 5 and 6. A lithographic printing plate precursor B was prepared. The dry coating amount was 1.3 g / m ² .

<Photosensitive layer coating solution (B)>
-The following binder polymer (1) (Mw: 80,000) 0.34 parts by mass-The following polymerizable compound (1) 0.68 parts by mass (PLEX6661-O, manufactured by Evonik Degussa Japan Co., Ltd.)
-0.06 parts by mass of the following sensitizing dye (1)-0.18 parts by mass of the following polymerization initiator (1)-0.02 parts by mass of the following chain transfer agent (1)-Dispersion of ε-phthalocyanine pigment 0.40 Parts by mass (pigments: 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio 83/17, Mw 60,000): 10 parts by mass, cyclohexanone: 15 parts by mass)
-Thermal polymerization inhibitor 0.01 parts by mass (N-nitrosophenylhydroxylamine aluminum salt)
-0.001 part by mass of the following fluorosurfactant (1) (Mw: 11,000)-0.02 part by mass of polyoxyethylene-polyoxypropylene condensate (manufactured by ADEKA, Pluronic L44)
-Dispersion of yellow pigment 0.04 parts by mass (yellow pigment Novoperm Yellow H2G (manufactured by Clariant): 15 parts by mass, dispersant (allyl methacrylate / methacrylic acid copolymer (copolymerization molar ratio 83/17), Mw 60,000) ): 10 parts by mass, cyclohexanone: 15 parts by mass)
-1-methoxy-2-propanol 3.5 parts by mass-Methyl ethyl ketone 8.0 parts by mass

(Formation of protective layer)
On the photosensitive layer, a protective layer coating solution (B) having the following composition was applied using a bar so that the dry coating amount was 1.0 g / m ^2, and then dried at 125 ° C. for 70 seconds to form a protective layer. And a negative planographic printing plate precursor (3) was obtained.

<Protective layer coating solution (B)>
-0.6 parts by weight of the following mica dispersion (B) 0.8 parts by weight of sulfonic acid-modified polyvinyl alcohol (Goselan CKS-50, manufactured by Nippon Synthetic Chemical Co., Ltd., degree of saponification: 99 mol%,
(Average polymerization degree: 300, modification degree: about 0.4 mol%)
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (Mw 70,000) 0.001 part by mass Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002 part by mass Water 13 part by mass

(Preparation of mica dispersion (B))
32 parts by mass of synthetic mica (Somasif ME-100, manufactured by Coop Chemical Co., Ltd., aspect ratio: 1,000 or more) was added to 368 parts by mass of water, and the average particle size (laser scattering method) was 0. 0 using a homogenizer. Dispersion was carried out until the thickness became 5 μm to obtain a mica dispersion (B).

(1) Exposure, development, plate surface processing and printing The obtained lithographic printing plate precursor was subjected to image exposure using FUJIFILM Electronic Imaging Ltd's Violet semiconductor laser plate setter Vx9600 (equipped with InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) Carried out. As the exposure image, an image in which drawn thin lines having a width of 5 to 100 μm (5 μm intervals) were arranged as the drawn thin line evaluation image was used. For printing durability evaluation, an image capable of solid printing durability evaluation was used. For image drawing, imagewise exposure was performed with a resolution of 2,400 dpi and a plate surface exposure of 0.05 mJ / cm ² .
Next, after preheating at 110 ° C. for 30 seconds using an automatic processor IP850HD manufactured by G & J, Inc., a solution (pH 12) obtained by diluting the developer DV-2 manufactured by Fuji Film Co., Ltd. 1: 4 is used. Development was carried out at 25 ° C. for 28 seconds, followed by washing with water.
The plate surface treatment was performed by changing the star polymer of the plate surface treating agent A to the star polymer described in Table 12 below.
Further, forced aging was performed at 60 ° C. for 4 days in the same manner as in Example 1, and the above-described exposure / development / plate surface treatment was performed, and evaluation for prevention of stop contamination was performed. The evaluation results are shown in Table 12.

  From Table 12, it can be seen that the occurrence of smudges in the non-image area after resumption of printing is improved by the plate surface treating agent of the present invention and the processing method of the lithographic printing plate of the present invention.

[Examples 69 to 82 and Comparative Examples 7 to 8]
In the formation of the undercoat layer, the following undercoat layer coating solution was used, and after applying the undercoat layer coating solution on the support using a bar coater so that the coating amount after drying was 10 mg / m ² , 80 ° C. In the same manner as described in Examples 55 to 68 and Comparative Examples 5 to 6, except for drying for 20 seconds, preparation of lithographic printing plate precursors of Examples 69 to 82 and Comparative Examples 7 to 8, The plate making of the lithographic printing plate and the evaluation of the obtained lithographic printing plate were performed, respectively.
The plate surface treatment was carried out by changing the star polymer of the plate surface treating agent A to the star polymer described in Table 13 below. The results are shown in Table 13.

<Coating liquid for undercoat layer>
・ 100 parts by mass of the following sol liquid 900 parts by mass of methanol

-Sol solution-
-Phosmer PE (manufactured by Unichemical Co., Ltd.) 5 parts by mass-45 parts by mass of methanol-10 parts by mass of water-5 parts by mass of phosphoric acid-20 parts by mass of tetraethoxysilane-15 parts by mass of 3-methacryloxypropyltrimethoxysilane Parts by mass

  From Table 13, it can be seen that the occurrence of smudges in the non-image area after the resumption of printing is improved by the plate surface treating agent of the present invention and the processing method of the lithographic printing plate of the present invention.

[Example 83 and Comparative Example 9]
The following undercoat coating solution (C) was applied to the support S-1 and dried at 80 ° C. for 15 seconds to provide an undercoat layer. The dry coating amount of the undercoat layer was 15 mg / m ² .

<Undercoat coating liquid (C)>
-Polymer compound represented by the following formula (I) (copolymerization ratio: molar ratio) 0.3 parts by mass-100 parts by mass of methanol-1 part by mass of water

[Formation of photosensitive layer]
After coating the photosensitive layer coating solution C-1 having the following composition on a support provided with an undercoat layer with a wire bar, the coating amount is 0.85 g / m ² by drying in a drying oven at 150 ° C. for 50 seconds. And a lower layer was provided.
Moreover, after providing a lower layer, the coating liquid C-2 for photosensitive layers of the following composition was apply | coated with the wire bar.
After the application, drying is performed at 140 ° C. for 60 seconds, and a positive planographic plate in which the component of the photosensitive layer coating solution C-2 is an upper layer so that the total coating amount of the lower layer and the upper layer is 1.1 g / m ^2. A printing plate master was obtained.

<Composition of photosensitive layer coating solution C-1>
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate (molar ratio 36/34/30, Mw 50,000) 1.920 parts by mass m, p-cresol novolak (m / p ratio = 6) / 4, Mw4000)
0.213 parts by mass-cyanine dye A represented by the following formula (A) 0.032 parts by mass-p-toluenesulfonic acid 0.008 parts by mass-tetrahydrophthalic anhydride 0.19 parts by mass-bis-p-hydroxy Phenylsulfone 0.126 parts by mass 2-methoxy-4- (N-phenylamino) benzenediazonium hexafluorophosphate 0.032 parts by mass Dye with Victoria Pure Blue BOH counter anion as 1-naphthalenesulfonate anion 0. 078 parts by mass-Fluorosurfactant (Megafac F-780, manufactured by DIC Corporation)
0.02 parts by mass-γ-butyrolactone 13.18 parts by mass-methyl ethyl ketone 25.41 parts by mass-1-methoxy-2-propanol 12.97 parts by mass

<Composition of photosensitive layer coating solution C-2>
Phenol / m, p-cresol novolak (phenol / m / p ratio = 5/3/2,
Mw 4,000) 0.274 parts by mass Cyanine dye A represented by the above formula (A) 0.029 parts by mass A polymer represented by the following formula (B) 30% by mass methyl ethyl ketone solution
0.14 parts by mass-quaternary ammonium salt represented by the following formula (C) 0.004 parts by mass-sulfonium salt represented by the following formula (D) 0.065 parts by mass-fluorine-based surfactant (mega Facque F-780, manufactured by DIC Corporation) 0.004 parts by mass Fluorosurfactant (Megafac F-782, manufactured by DIC) 0.020 parts by mass Methyl ethyl ketone 10.39 parts by mass 1-methoxy-2 -Propanol 20.98 parts by mass

<Exposure, development, plate processing and printing>
The obtained positive planographic printing plate precursor was subjected to imagewise exposure under the conditions of a beam intensity of 7.0 W and a drum rotation speed of 250 rpm using an exposure machine TrendSetter VX manufactured by CREO.
Next, development processing was performed with an automatic developing machine LP-1310H2 manufactured by FUJIFILM Corporation. As a developing solution, a solution obtained by diluting a developing solution DT-2R manufactured by Fuji Film Co., Ltd. 1: 6.5 (conductivity 50 mS / cm) is used. Processed.
The plate surface treatment was performed by changing the star polymer of the plate surface treating agent A to the star polymer described in Table 14 below.
Further, forced aging was performed at 60 ° C. for 4 days in the same manner as in Example 1, and the above-described exposure / development / plate surface treatment was performed, and evaluation for prevention of stop contamination was performed.
The evaluation results are shown in Table 14.

  From Table 14, it can be seen that the occurrence of smudges in the non-image area after resuming printing is improved by the plate surface treating agent of the present invention and the processing method of the lithographic printing plate of the present invention.

Claims (11)

  A plate surface treatment agent for a lithographic printing plate comprising a star polymer having at least one support-adsorbing group and at least one hydrophilic group.   The plate surface treating agent for a lithographic printing plate according to claim 1, wherein the star polymer is a star polymer having 3 branches or more and 10 branches or less.   The lithographic printing plate treating agent according to claim 1 or 2, wherein the star polymer has a polymer chain branched from 3 to 10 branches from a central skeleton through a sulfide bond.   A star polymer is a polymer obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polyfunctional thiol and having a polymer chain branched from 3 to 10 branches from the central skeleton via a sulfide bond. The plate surface treating agent for a lithographic printing plate according to any one of claims 1 to 3, wherein:   The support adsorbing group of the star polymer is at least one group selected from the group consisting of a phosphonic acid group and a salt thereof, a phosphate ester group and a salt thereof, and a carboxylic acid group and a salt thereof. The plate surface treating agent for a lithographic printing plate according to any one of claims 1 to 4, wherein:   The hydrophilic group of the star-shaped polymer is a sulfonic acid group and a salt thereof, an amide group, a polyalkylene oxide group, a hydroxyl group, a sulfuric acid monoester group and a salt thereof, a phosphonium group, a sulfonamide group, an amino group, a sulfuric acid monoamide group and The plate surface treating agent for a lithographic printing plate according to any one of claims 1 to 5, which is at least one group selected from the group consisting of the salt and a betaine structure.   The plate surface treatment agent for a lithographic printing plate according to any one of claims 1 to 6, comprising a water-soluble polymer compound and at least one selected from a phosphate and phosphoric acid.   The water-soluble polymer compound is gum arabic, a fibrous derivative and a modified product thereof, polyvinyl alcohol and a derivative thereof, polyvinyl pyrrolidone, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene. / Moleic anhydride copolymer, water-soluble soybean polysaccharide, starch, starch derivative, pullulan and pullulan derivative, gelatin, and at least one water-soluble polymer compound selected from the group consisting of hemicellulose extracted from soybean The plate surface treating agent for a lithographic printing plate according to claim 7, wherein   A lithographic process comprising a step of subjecting a lithographic printing plate precursor to image exposure, a step of developing with a developer, and a step of subjecting the lithographic printing plate to a plate surface treatment using the lithographic printing plate surface treating agent according to any one of claims 1 to 8. Processing method for printing plates.   The method for processing a lithographic printing plate according to claim 9, wherein the lithographic printing plate precursor has a support subjected to an electrochemical roughening treatment with an aqueous hydrochloric acid solution.   The lithographic printing plate processing method according to claim 9 or 10, wherein the lithographic printing plate precursor has a photosensitive layer containing a sensitizing dye, a polymerization initiator, and a binder polymer.

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