JP5433605B2 - Planographic printing plate precursor and plate making method - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor and a plate making method thereof. Specifically, the present invention relates to a lithographic printing plate precursor that can be directly made by laser image exposure and a plate making method for developing the lithographic printing plate precursor.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support is used. After exposure through a mask such as a film, development with an alkaline developer is performed to leave the image recording layer corresponding to the image area, and dissolve and remove the unnecessary image recording layer corresponding to the non-image area. And obtained a lithographic printing plate.

  Due to recent advances in this field, lithographic printing plates are now available with CTP (computer to plate) technology. That is, a lithographic printing plate can be obtained by scanning and exposing a lithographic printing plate precursor directly using a laser or a laser diode without a lith film, and developing it.

  Along with the above progress, problems related to the lithographic printing plate precursor have been changed to improvements in image formation characteristics, printing characteristics, physical characteristics and the like corresponding to the CTP technology. In addition, due to increasing interest in the global environment, environmental issues related to waste liquids associated with wet processing such as development processing have been highlighted as another issue related to lithographic printing plate precursors.

As a developing method, there is a method of developing with a highly alkaline developing solution. However, with respect to the environmental problems described above, simplification of development or plate making and no processing are directed. As one simple plate making method, a method called “on-press development” is performed. That is, after the exposure of the lithographic printing plate precursor, conventional development is not performed, but it is mounted on a printing machine as it is, and unnecessary portions of the image recording layer are removed at the initial stage of a normal printing process.
In addition, as a simple development method, a method called “gum development” in which unnecessary portions of the image recording layer are removed with a finisher or gum solution having a pH close to neutral instead of a conventional highly alkaline developer is also performed. ing.

  In the simplification of the plate making operation as described above, a system using a lithographic printing plate precursor and a light source that can be handled in a bright room or under a yellow light is preferable in terms of ease of work. A solid-state laser such as a semiconductor laser or a YAG laser emitting an infrared ray of 1200 nm is used. Further, a UV laser can be used.

As a lithographic printing plate precursor capable of on-machine development, for example, in Patent Documents 1 and 2, a lithographic printing plate having an image recording layer (thermosensitive layer) containing a microcapsule containing a polymerizable compound on a hydrophilic support. The original edition is listed. Patent Document 3 discloses an on-press developable lithographic printing in which an image recording layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. The original edition is listed.
Patent Document 4 discloses a lithographic printing plate precursor containing a compound having two or more isocyanuric acid skeletons having at least one substituent having a hydroxy group in order to improve both on-press developability and printing durability. Is described. Patent Document 5 describes a lithographic printing plate precursor using an image recording layer containing a star polymer in order to improve developability and printing durability. However, these techniques are still insufficient in terms of both developability and printing durability.

JP 2001-277740 A JP 2001-277742 A US Patent Application Publication No. 2003/0064318 JP 2010-234588 A JP 2007-249036 A

  An object of the present invention is to provide a lithographic printing plate precursor having high developability and good printing durability, and a plate making method using the same.

  As a result of intensive studies to achieve the above object, the present inventors have found that the problem can be achieved by including a star polymer and / or oligomer in the image recording layer, and have reached the present invention. The present invention is as follows.

1. A lithographic printing plate precursor having an image recording layer containing a hydrophobic binder, a radical polymerizable compound, a radical polymerization initiator, and at least one selected from a star polymer and an oligomer having a hydrophilic group on a support.
2. 2. The lithographic printing plate precursor as described in 1 above, wherein the hydrophilic group is at least one selected from an alkylene oxide group, a sulfonic acid group or a salt thereof, an amide group, and a betaine group.
3. 3. The lithographic printing plate precursor as described in 1 or 2 above, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group has a branched structure of 3 to 10 branches.
4). The lithographic printing plate as described in any one of 1 to 3 above, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group is branched from the central skeleton via a sulfide bond Original edition.
5. At least one selected from a star polymer and an oligomer having a hydrophilic group has an acid group from the central skeleton via a sulfide bond obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polyfunctional thiol. 5. The lithographic printing plate precursor as described in 4 above, wherein the polymer chain is a polymer branched from 3 branches to 10 branches.
6). The lithographic printing plate precursor as described in any one of 1 to 5 above, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group has a crosslinkable group.
7). The lithographic printing plate precursor as described in any one of 1 to 6 above, wherein the hydrophobic binder has an acid group, is insoluble in water, and is soluble in an alkaline aqueous solution.
8). The lithographic printing plate precursor as described in any one of 1 to 6 above, wherein the hydrophobic binder is insoluble in water and has a polyoxyethylene chain.
9. The lithographic printing plate precursor as described in 7 or 8 above, wherein the hydrophobic binder has a crosslinkable group.
10. 10. The method according to any one of 1 to 9 above, wherein after image exposure with a laser, printing ink and fountain solution can be supplied to remove the image recording layer in the unexposed area and print. The lithographic printing plate precursor described in 1.
11. The lithographic printing plate precursor as described in any one of 1 to 9 above, wherein the image recording layer in the unexposed area can be removed with a developer having a pH of 2 to 14.
12 12. The lithographic printing plate precursor as described in 11 above, wherein the image recording layer and the protective layer in the unexposed area can be removed with a one-bath developer.
13. 11. A lithographic printing method comprising printing the lithographic printing plate precursor as described in 10 above after exposing the image with a laser and then supplying printing ink and fountain solution to remove the unrecorded image recording layer.
14 A plate making method of a lithographic printing plate, comprising subjecting the lithographic printing plate precursor as described in 11 above to image exposure with a laser and then removing an image recording layer in an unexposed portion with a developer having a pH of 2 to 14.
15. 13. A method for making a lithographic printing plate, comprising subjecting the lithographic printing plate precursor as described in 12 above to image exposure with a laser, and then removing an image recording layer and a protective layer in an unexposed portion with a developing solution in one bath.

In the present invention, by using a star-shaped polymer and / or oligomer for the image recording layer, the problem of achieving both developability and printing durability can be achieved.
The mechanism of action is not necessarily clear, but is presumed as follows.
Since the star polymer and / or oligomer having the hydrophilic group of the present application has a star structure, the star polymer and / or oligomer does not interact and aggregate in the image recording layer, and the image As a result, when the star polymer and / or oligomer is present, the solubility (developability) of the unexposed area is improved. That is, the star polymer and / or oligomer functions as an excellent development accelerator. On the other hand, since the exposed portion has a star structure, it tends to get entangled in the network structure formed by radical polymerization, and does not escape from the image portion during development compared to conventional development accelerators. Thus, a firm image can be obtained and printing durability is improved.

  An object of the present invention is to provide a lithographic printing plate precursor having high developability and good printing durability, and a plate making method using the same.

It is a schematic diagram of the star polymer and / or oligomer of the present invention. It is explanatory drawing which shows the structure of an automatic image processor (A). It is explanatory drawing which shows the structure of an automatic image processor (B).

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the present invention is a lithographic printing plate precursor having a support, an image recording layer containing a binder, a radical polymerizable compound and a radical polymerization initiator in this order, and having a hydrophilic group in the image recording layer. A lithographic printing plate precursor comprising a star-shaped polymer and / or an oligomer having the same.
Hereinafter, the present invention will be described in detail.

(Image recording layer)
The image recording layer used in the lithographic printing plate precursor according to the invention comprises (A) a star polymer and / or oligomer having a hydrophilic group, (B) a hydrophobic binder, (C) a radical polymerization initiator, and (D) a radical. A polymerizable compound, (E) any other component can be contained.

(A) Star polymer and / or oligomer The star polymer and / or oligomer used in the image recording layer of the present invention is a polymer having a main chain structure as shown in the schematic diagram of FIG. Or it is an oligomer. That is, the polymer chain Pl has a structure in which one end of the polymer chain Pl is bonded to the central skeleton A, and is different from a graft polymer or the like in which one end of the polymer chain is bonded to the polymer chain.

  The mass average molar mass (Mw) of the star polymer and / or oligomer of the present invention is preferably from 500 to 50,000, more preferably from 1,000 to 25,000, particularly preferably from 1,000 to 10,000. Within this range, developability and printing durability are improved. In the present invention, an oligomer having an Mw smaller than 3000 is defined as an oligomer.

  As long as the star polymer and / or oligomer used in the present invention has the structure as described above, any star polymer and / or oligomer can be used. Examples of such star polymers and / or oligomers include star polymers and / or oligomers obtained by the coupling method or anion growth method described in “New Experimental Chemistry Course, Polymer Chemistry I”, edited by The Chemical Society of Japan, p208-210. And a star shape obtained by a synthesis method in which a compound containing a dithiocarbamate group and / or a compound containing a xanthate group described in JP-A-10-279867 is subjected to a polymerization reaction under light irradiation. Examples include polymers and / or oligomers, and star polymers and / or oligomers obtained by ordinary radical polymerization using polyfunctional thiols as chain transfer agents, but the ease of synthesis and the performance of the obtained polymers and / or oligomers. From the viewpoint of, using polyfunctional thiol as a chain transfer agent, It is preferably a star polymer and / or oligomer obtained Ri.

  The star polymer and / or oligomer of the present invention is preferably a polymer and / or oligomer having a polyfunctional thiol as a central skeleton (A) and a polymer chain (Pl) bonded to the central skeleton by a sulfide bond. . 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 a trivalent or higher organic group, and n is an integer of 3 or higher. Specific examples of A ₁ include organic groups having the following structures or a plurality of combinations 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 3 to 6.

  As the polyfunctional thiol used in the star polymer and / or oligomer of the present invention, any compound having a plurality of thiol groups in one molecule can be suitably used. The polyfunctional thiol is preferably 3 to 12 functional thiols, more preferably 3 to 10 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 an alcohol and a carboxylic acid having a thiol group. Among these, a compound obtained by a condensation reaction between a polyfunctional alcohol having 3 to 10 functional groups and a monocarboxylic acid having one thiol group is preferable.

  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), trimethylol Lopan (3), phloroglucinol (3), 1,1,1-tris (4-hydroxyphenyl) ethane (3), 1,3,5-tris (2-hydroxyethyl) isocyanurate (3), penta Erythritol (4), catechin (5), epicatechin (5), inositol (6), dipentaerythritol (6), tripentaerythritol (8) are more preferred, and 1,3,5-tris (2-hydroxyethyl) ) Isocyanurate (3), pentaerythritol (4), catechin (5), epicatechin (5), inositol (6), dipentaerythritol (6) and tripentaerythritol (8) are particularly preferred.

  Specific examples of the carboxylic acid having a thiol group include mercaptoacetic acid, 3-mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, N- (2-mercaptopropionyl) glycine, and thiosalicylic acid. Is mentioned. Of these, mercaptoacetic acid, 3-mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, and N- (2-mercaptopropionyl) glycine are preferable, and 3-mercaptopropionic acid and 2-mercaptopropionic acid are preferable. More preferred are acid, 3-mercaptoisobutyric acid, N-acetylcysteine, N- (2-mercaptopropionyl) glycine, 3-mercaptopropionic acid, 3-mercaptoisobutyric acid, N-acetylcysteine, N- (2-mercaptopropionyl) ) Glycine is particularly preferred.

  Specific examples of this compound include the following compounds. The present invention is not limited to these.

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 preferably 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-8 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, and particularly preferable 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, and 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 an 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-tetra Azaundecane (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 Samine (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), pentaethylenehe The summing (6), cyclen (4), more preferably hex Sai Clen (6), tetraethylenepentamine (5), pentaethylenehexamine (6), cyclen (4), hexa Sai Clen (6) 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 compound C 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 preferably SC- 37-SC-41, SC-44-SC-48, SC-51-SC-55, SC-58-SC-62, SC-65-SC-69, SC-72-SC-76, SC-79- 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, and particularly preferred SC-37 to SC-41, SC-86 to S -90, an SC-93~SC-97, SC-100~SC-104, SC-121~SC-125, SC-142~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. Among these, a compound obtained by a condensation reaction of a trifunctional or more than 10 functional polyfunctional alcohol amine and a monocarboxylic acid having one thiol group is preferable.

  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-aminoresorcino (3), norphenylephrine (3), octopamine (3), synephrine (3), 3,4-dihydroxybenzylamine (3), 3-hydroxytyramine (3), norephinephrine (4), 5-hydroxydopamine (4), 6-hydroxydopamine (4), serinol (3), 2-amino-2-methyl-1,3-propanediol (3), tris (hydroxymethyl) aminomethane (4), bis -Homotris (4), 1,3-diamino-2-hydroxypropane (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), norephine Phosphorus (4), 5-hydroxydopamine (4) and 6-hydroxydopamine (4) are preferred, and 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), and 6-hydroxydopamine (4) are particularly preferable.

  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 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, 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 are preferable. -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 carboxylic acid and an alcohol having a thiol group. Among these, a compound obtained by a condensation reaction between a polyfunctional carboxylic acid having 2 to 10 functional groups and an alcohol having at least one thiol group is preferable.

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 preferable, 2-mercaptoethanol (1) and 3-mercapto-1-propanol (1) are more preferable, and 3-mercapto-1-propanol (1) is particularly preferable.

  Specific examples of this compound include the compounds described in Table 4 and Table 5 below, but the present invention is not limited thereto.

  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, and SE-117 are preferred, and SE-12 is more preferred. , SE-14, SE-18, SE-20, SE-4 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, and SE-115.

  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 carboxylic acid and an amine having a thiol group. Among these, a compound obtained by a condensation reaction between a polyfunctional carboxylic acid having 2 to 10 functional groups and an amine having one or more thiol groups is preferable.

  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.

  Specific examples of this compound include the following compounds. 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, compounds A to E are preferable, compounds A to D are more preferable, and compounds A, B, and D are particularly preferable from the viewpoint of synthesis of a star polymer and / or an oligomer.

  The star polymer and / or oligomer used in the present invention is a polymer compound having a polyfunctional thiol as a central skeleton as described above and a polymer chain bonded to the central skeleton by a sulfide bond. Examples of the polymer chain in the star polymer and / or oligomer of the present invention include known vinyl polymers, (meth) acrylic acid polymers, and styrene polymers that can be produced by radical polymerization. Vinyl polymers, (meth) Acrylic acid polymers are particularly preferred.

A preferred example of the polymer chain used in the present invention includes a copolymer having a repeating unit containing a hydrophilic group. As the hydrophilic group, carboxylic acid (salt) group, sulfonic acid (salt) group, hydroxyl group, carboxylic acid amide group, sulfuric acid (salt) group, carbobetaine group, sulfobetaine group, phosphobetaine group, N-oxide group , Ammonium group, — (CH ₂ CH ₂ O) _n R, — (C ₃ H ₆ O) _m R (R represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, an alkenyl group, or an alkynyl group. And n and m represent an integer of 1 to 100) and combinations thereof. Among these hydrophilic functional groups, a sulfonic acid (salt) group, a hydroxyl group, a carboxylic acid amide group, a carbobetaine group, a sulfobetaine group, and — (CH ₂ CH ₂ O) _n R are more preferable. These hydrophilic groups are preferably contained at 0.1 mmol / g or more and 50 mmol / g or less, and more preferably 0.5 mmol / g or more and 45 mmol / g or less, per 1 g of the star polymer and / or oligomer. Preferably, it is contained at 1.0 mmol / g or more and 40 mmol / g or less. By making the content, the developability of the image recording layer becomes better.

  The polymer chain used in the present invention preferably further has a crosslinkable group. Here, the crosslinkable group is a group that crosslinks a polymer chain in the course of a radical polymerization reaction that occurs in an image recording layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, etc. are mentioned, for example. Of these, an ethylenically unsaturated bond group is preferable. Examples of the ethylenically unsaturated bond group include a (meth) acryloyl group, an allyl group, and a vinyl group.

In the polymer chain used in the present invention, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of the polymerizable compound) are added to the crosslinkable functional group, and polymerization of the polymerizable compound is performed directly between the polymer chains. Addition polymerization through a chain forms a cross-link between polymer chains and cures. Alternatively, atoms in the polymer chain (for example, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are extracted by free radicals to form polymer radicals that are bonded to each other, thereby crosslinking between the polymer chains. Is formed and hardened.
The content of the crosslinkable group of the polymer chain used in the present invention (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.01 to 10.0 mmol per 1 g of the star polymer. Preferably it is 0.05-9.0 mmol, Most preferably, it is 0.1-8.0 mmol.

  The polymer chain used in the present invention is a polymer unit having a hydrophilic group, a polymer unit having a crosslinkable group, a polymer unit of (meth) acrylate or aralkyl ester, (meth) acrylamide or a derivative thereof. It may have a polymerization unit, a polymerization unit of α-hydroxymethyl acrylate, and a polymerization unit of a 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.

  Specific examples of the star polymer and / or oligomer used in the present invention are shown below, but the present invention is not limited thereto.

The star polymer and / or oligomer of the present invention may be used alone or in combination of two or more. Moreover, you may use together with a normal linear polymer.
The content of the star polymer and / or oligomer of the present invention in the image recording layer is preferably 0.1% by mass or more and 60% by mass or less, and preferably 0.25% by mass or more and 50% by mass with respect to the total solid content of the image recording layer. The mass% is more preferable, and 0.5 mass% or more and 40 mass% or less is particularly preferable.

(B) Hydrophobic binder As the hydrophobic binder, those capable of supporting the image recording layer component on the support and removable with a developer, or those removable on a printing press are used. The hydrophobic binder is insoluble in water, for example, (1) a binder having an acid group, insoluble in water and soluble in an alkaline aqueous solution, and (2) having a hydrophilic group and insoluble in water. A certain binder can be mentioned.

As the hydrophobic binder, (meth) acrylic polymer, polyurethane resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, epoxy resin and the like are used. In particular, (meth) acrylic polymers and polyurethane resins are preferably used. These resins may have any of a linear shape, a graft shape, and a star shape. Further, the constituent components of the resin may be random or block-shaped.
In the present invention, “(meth) acrylic polymer” means (meth) acrylic acid, (meth) acrylic acid ester (alkyl ester, aryl ester, allyl ester, etc.), (meth) acrylamide and (meth) acrylamide derivatives. It refers to a copolymer having a (meth) acrylic acid derivative such as “Polyurethane resin” refers to a polymer produced by a condensation reaction of a compound having two or more isocyanate groups and a compound having two or more hydroxyl groups. “Polyvinyl butyral resin” refers to a polymer synthesized by reacting polyvinyl alcohol obtained by saponifying a part or all of polyvinyl acetate and butyraldehyde under an acidic condition (acetalization reaction). Further, a polymer having an acid group or the like introduced by a method of reacting a remaining hydroxy group with a compound having an acid group or the like is also included. In the present invention, “(meth) acrylic polymer” is most preferable.

(1) Hydrophobic binder having an acid group, insoluble in water, and soluble in an alkaline aqueous solution In the present invention, as a preferred example of the binder removable by the developer in the present invention, an acid group is contained. A copolymer having a repeating unit may be mentioned. Examples of the acid group include a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid group, a phenolic hydroxyl group, and a sulfonamide group, and a carboxylic acid group is particularly preferable. As the repeating unit containing an acid group, a repeating unit derived from (meth) acrylic acid or a repeating unit represented by the following general formula (I) is preferably used.

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

The linking group represented by R ² in the general formula (I) is composed of a hydrogen atom, a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, and the number of atoms is preferably 1 to 80. is there. Specific examples include an alkylene group, a substituted alkylene group, an arylene group, a substituted arylene group, and the like. These divalent groups may be any one of an amide bond, an ether bond, a urethane bond, a urea bond, and an ester bond. You may have the structure connected. R ² is preferably a single bond, an alkylene group or a substituted alkylene group, particularly preferably a single bond, an alkylene group having 1 to 5 carbon atoms, or a substituted alkylene group having 1 to 5 carbon atoms. And most preferably an alkylene group having 1 to 3 carbon atoms and a substituted alkylene group having 1 to 3 carbon atoms.

  Examples of the substituent include a monovalent non-metallic atomic group excluding a hydrogen atom, a halogen atom (—F, —Br, —Cl, —I), a hydroxyl group, an alkoxy group, an aryloxy group, a mercapto group, An acyl group, a carboxyl group and its conjugate base group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an aryl group, an alkenyl group, an alkynyl group and the like can be mentioned.

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

  The proportion of the copolymer component having a carboxylic acid group in the total copolymer components of the hydrophobic binder is preferably 1 to 70 mol% from the viewpoint of developability. In consideration of compatibility between developability and printing durability, 1 to 50 mol% is more preferable, and 1 to 30 mol% is particularly preferable.

Examples of the repeating unit represented by the general formula (I) include repeating units described in paragraph numbers [0059] to [0071] of JP-A-2007-94138.
Specific examples of the repeating unit having an acid group are shown below.

(2) Hydrophobic binder having a hydrophilic group and insoluble in water As a suitable example of the binder removable by on-press development in the present invention, a copolymer having a repeating unit containing a hydrophilic group is used. Can be mentioned. As the hydrophilic group, carboxylic acid (salt) group, sulfonic acid (salt) group, hydroxyl group, carboxylic acid amide group, sulfuric acid (salt) group, carbobetaine group, sulfobetaine group, phosphobetaine group, N-oxide group , Ammonium group, — (CH ₂ CH ₂ O) _n R, — (C ₃ H ₆ O) _m R (R represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, an alkenyl group, or an alkynyl group. And n and m represent an integer of 1 to 100), and combinations thereof. Among these hydrophilic functional groups, sulfonic acid (salt) group, hydroxyl group, carboxylic acid amide group, carbobetaine group, sulfobetaine group, phosphobetaine group, and — (CH ₂ CH ₂ O) _n R are more preferable. An acid amide group, — (CH ₂ CH ₂ O) _n R is more preferable, and — (CH ₂ CH ₂ O) _n R is most preferable.

  The proportion of the copolymer component having a hydrophilic group in the total copolymer components of the hydrophobic binder is preferably 1 to 70 mol% from the viewpoint of developability. Considering compatibility between developability and printing durability, 1 to 60 mol% is more preferable, and 1 to 50 mol% is particularly preferable.

  The hydrophobic binder used in the present invention preferably further has a crosslinkable group. Examples of the crosslinkable group include the same crosslinkable groups in the star polymer and / or oligomer. Especially, an ethylenically unsaturated bond group is preferable and a (meth) acryloyl group, an allyl group, and a vinyl group are preferable.

  By introducing a crosslinkable group, a crosslinking reaction is formed between the hydrophobic binder and further between the hydrophobic binder and the crosslinkable group of the polymerizable compound, star polymer and / or oligomer in a polymerization reaction initiated by exposure. The image intensity can be further improved.

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

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

  The hydrophobic binder preferably has a mass average molar mass (Mw) of 5000 or more, more preferably 10,000 to 300,000, and a number average molar mass (Mn) of 1000 or more. More preferably, it is 2000-250,000. The polydispersity (Mw / Mn) is preferably 1.1-10.

The hydrophobic binder may be used alone or in combination of two or more. The content of the hydrophobic binder is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, based on the total solid content of the image recording layer, from the viewpoint of good image area strength and image formability. More preferably, it is 10-60 mass%.
The total content of the polymerizable compound and the hydrophobic binder is preferably 80% by mass or less with respect to the total solid content of the image recording layer. If it is 80 mass% or less, a sensitivity and developability improve more and it is preferable. More preferably, it is 35-75 mass%.

  The mass ratio [(A) / (B)] of (B) the hydrophobic binder and (A) the star polymer and / or oligomer is preferably 1 / 0.5 to 0.05 / 1. More preferably, it is in the range of 1/1 to 0.1 / 1.

  Specific examples of the binder having a hydrophilic group and insoluble in water are shown below.

(C) Polymerization initiator The image recording layer of the invention contains a polymerization initiator (hereinafter also referred to as an initiator compound). In the present invention, a radical polymerization initiator is preferably used.
As the initiator compound in the present invention, those known among those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds can be used. , Hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds and onium salts are particularly preferable. Two or more of the above polymerization initiators can be used in combination as appropriate.

Examples of the hexaarylbiimidazole compounds include lophine dimers described in the specifications of European Patent No. 24629, European Patent No. 107792, and US Pat. No. 4,410,621, 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-nitropheny ) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'- Bis (o-trifluoromethylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole and the like can be mentioned.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 300 to 450 nm.

As the onium salt suitably used in the present invention, a sulfonium salt, an iodonium salt, and a diazonium salt are preferably used. In particular, diaryliodonium salts and triarylsulfonium salts are preferably used. The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption at 750 to 1400 nm.
As other polymerization initiators, polymerization initiators described in JP-A 2007-206217, paragraph numbers [0071] to [0129] 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 image recording 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 image recording layer. More preferably, it is 1.0 mass%-10 mass%.

(D) Polymerizable Compound The polymerizable compound used in the image recording layer in the invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, preferably at least one terminal ethylenically unsaturated bond. Is selected from compounds having two or more. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, 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. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

  Specific examples of the monomer of the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

  In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (A) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.

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

  Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide skeleton described in the publication, and hydrophilic groups described in US Pat. No. 7,153,632, JP-A-8-505958, JP-A-2007-293221, and JP-A-2007-293223. Also suitable are urethane compounds having.

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

(E) Other components The image recording layer used in the present invention may contain a sensitizing dye and the like in addition to the above-described star polymer and / or oligomer, hydrophobic binder, polymerization initiator, and polymerizable compound. .

(Sensitizing dye)
The image recording layer of the present invention preferably contains a sensitizing dye. The sensitizing dye is particularly limited as long as it absorbs light at the time of image exposure to be in an excited state and supplies energy to the polymerization initiator by electron transfer, energy transfer or heat generation to improve the polymerization initiation function. It can be used without. In particular, a sensitizing dye having a maximum absorption at 300 to 450 nm or 750 to 1400 nm is preferably used.

Examples of the sensitizing dye having maximum absorption in the wavelength range of 350 to 450 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, styryls, oxazoles, and the like.
Of the sensitizing dyes having an absorption maximum in the wavelength range of 360 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (2).

(In general formula (2), A represents an aryl group or heteroaryl group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a monovalent non-metallic atomic group, and A and R ₁ and R ₂ and R ₃ may be bonded to each other to form an aliphatic or aromatic ring. .)

General formula (2) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or unsubstituted An aryl group, a substituted or unsubstituted heteroaryl residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, and a halogen atom.

Specific examples of such a sensitizing dye include paragraph numbers [0047] to [0053] of JP-A No. 2007-58170, paragraph numbers [0036] to [0037] of JP-A No. 2007-93866, and JP-A No. 2007. The compounds described in paragraph Nos. [0042] to [0047] of JP-72816 are preferably used.
JP-A-2006-189604, JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, JP-A-2007-316582 The sensitizing dyes described in JP-A-2007-328243 are also preferably used.
Moreover, these sensitizing dyes may use only 1 type and may use 2 or more types together.

  Subsequently, a sensitizing dye having a maximum absorption at 750 to 1400 nm that is preferably used in the present invention (hereinafter, sometimes referred to as “infrared absorber”) will be described in detail. As the infrared absorber, a dye or a pigment is preferably used.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
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 general 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 represent a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² may be connected to each other to form a ring. Well, when forming a ring, it is particularly preferable to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aryl group which may have a substituent. Preferred aryl 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, carboxylic acid groups, and sulfonic acid groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used in the present invention include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and JP-A No. 2002-023360. Paragraph numbers [0012] to [0021] of JP-A No. 2002-040638, compounds described in paragraph Nos. [0012] to [0037] of JP-A No. 2002-040638, preferably paragraph Nos. [0034] of JP-A No. 2002-278057 [0041], compounds described in JP-A-2008-195018, paragraph numbers [0080] to [0086], most preferably compounds described in JP-A-2007-90850, paragraph numbers [0035] to [0043]. It is done.
Further, compounds described in paragraphs [0008] to [0009] of JP-A-5-5005 and paragraphs [0022] to [0025] of JP-A-2001-222101 can also be preferably used.

  Moreover, only 1 type may be used for these (A) infrared absorption dyes, and 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, compounds described in paragraph numbers [0072] to [0076] of JP-A-2008-195018 are preferable.

  The preferred addition amount of these sensitizing dyes is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, and most preferably 0.2 to 10% by mass with respect to the total solid content of the image recording layer. It is the range of mass%.

(Other image recording layer components)
The image recording layer of the present invention can further contain various additives as required. Additives include surfactants for improving developability and improving the surface of the coating, microcapsules for achieving both developability and printing durability, and improving the developability and dispersion stability of microcapsules. Hydrophilic polymer, colorant and print-out agent for visually recognizing image area and non-image area, polymerization inhibitor for preventing unnecessary thermal polymerization of radical polymerizable compound during production or storage of image recording layer Hydrophobic low molecular weight compounds such as higher fat derivatives to prevent polymerization inhibition by oxygen, inorganic fine particles to improve the cured film strength of the image area, organic fine particles, hydrophilic low molecular weight compounds to improve developability, sensitivity A co-sensitizer and a chain transfer agent for improving, a plasticizer for improving plasticity, a sensitizing agent for improving the inking property, and the like can be added. Any of these compounds can be used, for example, compounds described in JP-A 2007-206217, paragraph numbers [0161] to [0215], JP-T 2005-509192, paragraph number [0067], The compounds described in paragraph Nos. [0023] to [0026] and [0059] to [0066] of Kokai No. 2004-310000 can be used. As for the surfactant, a surfactant which may be added to the developer described later can also be used.

The image recording layer preferably contains a chain transfer agent. The chain transfer agent is defined, for example, in Polymer Dictionary 3rd Edition (edited by Polymer Society, 2005), pages 683-684. As the chain transfer agent, for example, a compound group having SH, PH, SiH, GeH in the molecule is used. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals.
In the image recording layer of the present invention, in particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) ) Can be preferably used.
A preferable addition amount of the chain transfer agent is preferably 0.01 to 20% by mass, more preferably 1 to 10% by mass, and most preferably 1 to 5% by mass with respect to the total solid content of the image recording layer. is there.

  In the image recording layer of the present invention, a sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer can be used in the image recording layer in order to improve the inking property. In particular, when an inorganic layered compound is contained in the protective layer, these compounds function as a surface coating agent for the inorganic layered compound, and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable compounds include phosphonium compounds, amine salts, quaternary ammonium salts, imidazolinium salts, benzimidazolinium salts, pyridinium salts described in JP-A-2006-297907 and JP-A-2007-50660, Examples thereof include quinolinium salts and ammonium group-containing polymers described in JP-A-2009-208458.

  The content of the sensitizer is preferably 0.01 to 30.0% by mass, more preferably 0.1 to 15.0% by mass and 1 to 10% by mass with respect to the total solid content of the image recording layer. Is more preferable.

<Formation of image recording layer>
The image recording layer of the present invention is formed by preparing or applying a coating liquid by dispersing or dissolving the necessary components described above in a solvent. Examples of the solvent used here include methyl ethyl ketone, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, and γ-butyllactone. It is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The coating amount of the image-recording layer on the support after drying (solid content), 0.3 to 3.0 g / m ² is preferred. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

[Protective layer]
In the lithographic printing plate precursor according to the invention, a protective layer (oxygen blocking layer) is preferably provided on the image recording layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. As a material that can be used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like. Among these, it is preferable to use a water-soluble polymer compound having relatively excellent crystallinity. Specifically, the use of polyvinyl alcohol as a main component is based on basic characteristics such as oxygen barrier properties and development removability. Give the best results.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Polyvinyl alcohol can be obtained by hydrolyzing polyvinyl acetate. Specific examples of polyvinyl alcohol include 69.0 to 100 mol% hydrolyzed and those having a polymerization repeating unit in the range of 300 to 2400. . Specifically, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, manufactured by Kuraray Co., Ltd. PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235, PVA-217EE, PVA-217E, PVA- 220E, PVA-224E, PVA-403, PVA-405, PVA-420, PVA-424H, PVA-505, PVA-617, PVA-613, PVA-706, L-8, etc., which may be used alone or Can be mixed and used. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

Moreover, well-known modified polyvinyl alcohol can also be used preferably. In particular, acid-modified polyvinyl alcohol having a carboxylic acid group or a sulfonic acid group is preferably used. Specific examples include polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137.
In the case of using a mixture of polyvinyl alcohol and another material, the component to be mixed is preferably modified polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof from the viewpoint of oxygen barrier properties, development removability, and the content in the protective layer is It is preferable that it is 3.5-80 mass%, More preferably, it is 10-60 mass%, More preferably, it is 15-30 mass%.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.

  Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic layered compound for the purpose of improving oxygen barrier properties and image recording layer surface protection. Among inorganic layered compounds, fluorine-based swellable synthetic mica, which is a synthetic inorganic layered compound, is particularly useful. Specifically, inorganic layered compounds described in JP-A No. 2005-119273 are preferable.

  As the protective layer, US Pat. No. 3,458,311 specification, Japanese Patent Publication No. 55-49729, Japanese Patent Application Laid-Open No. 2008-15503, Japanese Patent Application Laid-Open No. 2008-89916, Japanese Patent Application Laid-Open No. 2008-139913. The protective layers described in the paragraph numbers [0211] to [0261] can be preferably used.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ² as the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 5 g / m ^2. In the case where the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

<Formation of protective layer>
The protective layer according to the present invention is a protective layer coating solution prepared by preparing a dispersion of a mica compound, if necessary, and mixing the dispersion and the binder component (or an aqueous solution in which the binder component is dissolved). Is applied on the image recording layer.

An example of a general dispersion method of the mica compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable mica compound mentioned above as a preferable mica compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electromagnetic distortion ultrasonic generator, An emulsifying device having a Paulman whistle can be used. The dispersion of 2 to 15% by mass of the mica compound thus dispersed is highly viscous or gelled, and the storage stability is very good.
When preparing a coating solution for a protective layer using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then mixing with a binder component (or an aqueous solution in which the binder component is dissolved).

  Known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the coating film can be added to the coating solution for the protective layer. Examples of the surfactant include anionic surfactants such as sodium alkylsulfate and sodium alkylsulfonate, amphoteric surfactants such as alkylaminocarboxylate and alkylaminodicarboxylate, and nonoxygen such as polyoxyethylene alkylphenyl ether. An ionic surfactant is mentioned. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, a known additive for improving the adhesion with the image recording layer and the temporal stability of the coating solution may be added to the coating solution.

  The method for coating the protective layer according to the present invention is not particularly limited, and a method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. .

The coating amount of the protective layer according to the present invention is preferably 0.1 to 2.0 g / m ² , more preferably 0.3 to 1.5 g / m ² . When it is 0.1 g / m ² or more, the film strength of the protective layer can be sufficiently maintained, and scratch resistance is not deteriorated. In addition, when it is 2.0 g / m ² or less, the removability of the protective layer in the development process is further improved, the oxygen permeability is not lowered excessively, and the suitability for safe light is not deteriorated. It is preferable because it does not mix in a large amount and the residue does not easily precipitate.

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

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

<Support hydrophilic treatment, undercoat layer>
In the lithographic printing plate precursor according to the invention, in order to improve the hydrophilicity of the non-image area and prevent printing stains, the support surface is subjected to a hydrophilic treatment after the anodizing treatment, or the support and image recording are performed. It is preferable to perform at least one of providing an undercoat layer between the layers.
Examples of the hydrophilization treatment of the support surface include alkali metal silicate treatment in which the support is immersed in an aqueous solution such as sodium silicate or electrolytic treatment, a method of treatment with potassium zirconate fluoride, a method of treatment with polyvinylphosphonic acid, and the like. Although mentioned, the method of immersing in the polyvinylphosphonic acid aqueous solution is used preferably.

As the undercoat layer, an undercoat layer having a compound having an acid group such as phosphonic acid, phosphoric acid or sulfonic acid is preferably used. These compounds preferably further contain a polymerizable group in order to improve adhesion to the image recording layer. As the polymerizable group, an ethylenically unsaturated bond group is preferable. Furthermore, compounds having a hydrophilicity-imparting group such as an ethyleneoxy group can also be mentioned as suitable compounds. These compounds may be low molecular weight or high molecular weight polymers. Moreover, you may use these compounds in mixture of 2 or more types as needed.
Silane coupling agent having an ethylenically unsaturated bond group capable of addition polymerization described in JP-A-10-282679, and having an ethylenically unsaturated bond group described in JP-A-2-304441 Preferred examples include phosphorus compounds. Crosslinkable group (preferably ethylenically unsaturated bond group) described in JP-A-2005-238816, JP-A-2005-12549, JP-A-2006-239867, JP-A-2006-215263, surface of support Those containing a low-molecular or high-molecular compound having a functional group that interacts with each other and a hydrophilic group are also preferably used.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

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

[Plate making method]
The plate making method of the lithographic printing plate of the present invention includes at least a step of image-exposing a lithographic printing plate precursor (hereinafter also referred to as “exposure step”) and a step of developing with a processing solution (hereinafter referred to as “developing step”). It is preferable that the method includes:

<Exposure process>
The lithographic printing plate precursor used in the present invention is obtained by scanning and exposing digital data with a laser such as a visible light laser or an infrared laser, or by exposing a digital original with a light source such as a halogen lamp or a high-pressure mercury lamp through a transparent original image. An image can be recorded, but a scanning exposure method using a laser such as a visible laser or an infrared laser is preferred.
A desirable light source wavelength is preferably 300 nm to 450 nm or 750 nm to 1400 nm. In the case of 300 nm to 450 nm, a lithographic printing plate precursor having a sensitizing dye having an absorption maximum in this region in the image recording layer is used, and in the case of 750 nm to 1400 nm, infrared rays which are sensitizing dyes having absorption in this region. A lithographic printing plate precursor containing an absorbent is used. As the light source of 300 nm to 450 nm, a semiconductor laser is suitable. As the light source of 750 nm to 1400 nm, a solid-state laser and a semiconductor laser that emit infrared rays are suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, and the like.

<Development process>
The lithographic printing plate precursor used in the present invention is exposed to light and then developed with water or a developer (developer treatment), or developed with dampening water and ink on a printing press (on-press development).

  The developer treatment is usually performed in the following steps. (1) Remove non-image area with developer, (2) Implement gum solution treatment, (3) Dry in drying step. The lithographic printing plate precursor used in the present invention can be developed by a normal process (normal development), but it is preferable to perform the steps (1) and (2) simultaneously (simple development). In any development method, a water washing step for removing the protective layer may be performed before the step (1). The development in step (1) is carried out according to a conventional method at a temperature of 0 to 60 ° C., preferably about 15 to 40 ° C., for example, by immersing an exposed lithographic printing plate precursor in a developer and rubbing with a brush, spraying By a method of spraying a developer and rubbing with a brush.

  In the case of normal development, a water washing step for removing excess developer may be inserted between step (1) and step (2). Moreover, it is preferable to use a well-known alkali developing solution as a developing solution used for a process (1).

In the case of simple development, it is preferable to dry after removing the excess developer using a squeeze roller after development and gumming.
The developer used in the simple development is an aqueous solution having a pH of 2 to 11. An aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution containing a surfactant (anionic, nonionic, cationic, amphoteric ion, etc.) or a water-soluble polymer compound. An aqueous solution containing is preferred. An aqueous solution containing both a surfactant and a water-soluble polymer compound is also preferred. The pH of the developer is more preferably 5 to 10.7, still more preferably 6 to 10.5, and most preferably 7.5 to 10.3.

  The anionic surfactant used in the developer for simple development is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinic acid salts, linear alkylbenzenesulfonic acid salts Branched alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl alkyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methylalkyl-N- Sodium oleyl taurine, disodium N-alkylsulfosuccinate monoamide, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate ester of fatty acid alkyl ester Salts, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene Alkyl ether phosphoric acid ester salts, polyoxyethylene alkylphenyl ether phosphoric acid ester salts, partial saponification products of styrene-maleic anhydride copolymer, partial saponification products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensation Things etc. are mentioned. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

  Although it does not specifically limit as a cationic surfactant used for the developing solution of simple development, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, alkyl imidazolinium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  The nonionic surfactant used in the developer for simple development is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct. , Naphthol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide addition Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) Side) block copolymer, fatty acid ester of polyhydric alcohol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. Is mentioned. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.

  The zwitterionic surfactant used in the developer for simple development is not particularly limited, and examples thereof include amine oxides such as alkyldimethylamine oxide, betaines such as alkylbetaine, and amino acids such as alkylamino fatty acid sodium. . In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specific examples thereof include compounds represented by the formula (2) in paragraphs [0255] to [0278] [0256] of JP-A-2008-203359, paragraph numbers [0028] to [0052 of JP-A-2008-276166. ] [0028] compounds represented by formulas (I), (II) and (VI), and compounds represented by paragraph numbers [0022] to [0029] of JP-A-2009-47927. Things can be used.

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

  Examples of the water-soluble polymer compound used in the developing solution for simple development include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan. , Polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, polyvinyl sulfone Examples include acids and salts thereof, polystyrene sulfonic acids and salts thereof, and the like.

A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.
As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice, and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the developer is preferably from 0.1 to 20% by mass, and more preferably from 0.5 to 10% by mass.

The developer used for simple development can further contain a pH buffer.
As the pH buffering agent of the present invention, any buffering agent that exhibits a buffering action at pH 2 to 11 can be suitably used. In the present invention, weakly alkaline buffering agents are preferably used, such as (a) carbonate ions and hydrogen carbonate ions, (b) borate ions, (c) water-soluble amine compounds and ions of the amine compounds, and their Combination use etc. are mentioned. That is, for example, a combination of (a) carbonate ion-bicarbonate ion, (b) borate ion, or (c) water-soluble amine compound-amine compound ion exhibits pH buffering action in the developer. Even when the developer is used for a long period of time, fluctuations in pH can be suppressed, and deterioration in developability due to fluctuations in pH, development of development residue, and the like can be suppressed. Particularly preferred is a combination of carbonate ions and bicarbonate ions.
In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and hydrogen carbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, potassium and the like, and sodium is particularly preferable. These may be used alone or in combination of two or more.
When (a) a combination of carbonate ions and bicarbonate ions is employed as the pH buffer, the total amount of carbonate ions and bicarbonate ions is preferably 0.05 to 5 mol / L with respect to the total mass of the aqueous solution, 0.1 ˜2 mol / L is more preferable, and 0.2 to 1 mol / L is particularly preferable.

  Further, the developer used for simple development may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). , Xylene, etc.), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, tricrene, monochlorobenzene, etc.) and polar solvents. Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1 -Nonanol, 1-decanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, polyethylene glycol monomethyl Ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether Ter, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone) , Cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate Etc.), others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine) , N- phenyldiethanolamine, N- methyldiethanolamine, N- ethyldiethanolamine, 4- (2-hydroxyethyl) morpholine, N, N- dimethylacetamide, N- methylpyrrolidone, etc.) and the like. Two or more of these organic solvents can be used in combination.

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

  In addition to the above, the developer of the present invention may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like. Specifically, compounds described in paragraph numbers [0266] to [0270] of JP-A-2007-206217 can be preferably used.

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

  The development treatment with an aqueous solution having a pH of 2 to 11 in the present invention can be preferably carried out by an automatic processor equipped with a developer supply means and a rubbing member. An automatic processor using a rotating brush roll as the rubbing member is particularly preferable. Further, the automatic processor is preferably provided with a means for removing excess developer such as a squeeze roller and a drying means such as a hot air device after the development processing means.

  In addition, as the plate-making process of the lithographic printing plate from the lithographic printing plate precursor according to the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. By such heating, an image forming reaction in the image recording layer is promoted, and advantages such as improvement in sensitivity and printing durability and stabilization of sensitivity may occur. Further, for the purpose of improving the image strength and printing durability, it is also effective to subject the developed image to full post heating or full exposure. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as curing of the unexposed area occur. Very strong conditions are used for heating after development. Usually, it is the range of 100-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

The lithographic printing plate precursor according to the invention can also be made by an on-press development method. The on-press development method includes a step of image-exposing a lithographic printing plate precursor, a printing step of supplying an oil-based ink and an aqueous component and printing without performing any development treatment on the exposed lithographic printing plate precursor, And the unexposed portion of the lithographic printing plate precursor is removed during the printing process. Imagewise exposure may be performed on the printing machine after the lithographic printing plate precursor is mounted on the printing machine, or may be separately performed with a plate setter or the like. In the latter case, the exposed lithographic printing plate precursor is mounted on a printing machine without undergoing a development process. Thereafter, by using the printing machine and supplying the oil-based ink and the aqueous component and printing as it is, an on-press development process, that is, an image recording layer in an unexposed area is removed at an early stage of printing, Accordingly, the surface of the hydrophilic support is exposed to form a non-image part. As the oil-based ink and the aqueous component, ordinary lithographic printing ink and fountain solution are used.
Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink.
In this way, the lithographic printing plate precursor according to the invention is developed on the machine on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the polymer compounds (including oligomers), 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.

[Synthesis example of star polymer]

Synthesis of star polymer (P-1) 1-methoxy-2-propanol heated to 70 ° C. under a nitrogen stream: 37.97 g, vinyl acetate: 51.65 g, SA-3: 1.26 g, V-601 (Wako Pure Chemical Industries, Ltd.): A mixed solution consisting of 0.691 g and 1-methoxy-2-propanol: 39.98 g was added dropwise over 2 hours and 30 minutes. After completion of the dropping, stirring was continued for 2 hours, and then a solution obtained by dissolving V-601: 0.069 g in 1-methoxy-2-propanol: 0.876 g was added, and the temperature was raised to 90 ° C. for 2 hours 30 The reaction continued for a minute. After the reaction, after cooling to room temperature, 77.95 g of methanol was added to dilute the reaction mixture. To the stirring dilution, 0.5M methanol-sodium hydroxide solution: 600 g was added dropwise over 3 hours. After completion of the dropwise addition, stirring was stopped, and saponification was completed by allowing to stand at room temperature for 2 nights. The precipitated solid was filtered and washed with methanol, whereby the star polymer (P-1) shown in Table 7 was obtained. In addition, the mass mean molar mass (Mw) which measured the polymer before saponification by GPC was 0.960,000.

Synthesis of star polymer (P-33) 1-methoxy-2-propanol heated to 70 ° C. under nitrogen stream: 41.42 g, N, N-dimethylacrylamide: 35.69 g, methyl acrylate: 20.66 g Dipentaerythritol hexakis (3-mercaptopropionate): 7.83 g, V-601 (manufactured by Wako Pure Chemical Industries, Ltd.): 0.691 g, 1-methoxy-2-propanol: 38.58 g The mixed solution was added dropwise over 2 hours and 30 minutes. After completion of the dropping, stirring was continued for 2 hours, and then a solution obtained by dissolving V-601: 0.069 g in 1-methoxy-2-propanol: 0.876 g was added, and the temperature was raised to 90 ° C. for 2 hours 30 The reaction continued for a minute. After the reaction, after cooling to 50 ° C., 1-methoxy-2-propanol was added to dilute the reaction mixture. The mass average molar mass (Mw) measured by GPC of the star polymer (P-33) solution described in Table 9 was 0.570,000, and the solid content concentration was 24.5% by mass. .

 [Examples 1 to 5 and Comparative Examples 1 to 4]

[I] Preparation of lithographic printing plate precursors (1) to (8) (1) Preparation of support 1 In order to remove rolling oil on the surface of a 0.3 mm thick aluminum plate (material JIS A 1050), 10% by mass After degreasing treatment with sodium aluminate aqueous solution at 50 ° C. for 30 seconds, three bundled nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension having a median diameter of 25 μm (specific gravity 1.1 g / cm) ³ ), the aluminum surface was grained and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

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

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
Next, the plate was provided with a direct current anodic oxide film having a current density of 15 A / dm ² and a current density of 15 g / m ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, followed by washing with water. It dried and produced the support body (1).

Thereafter, in order to ensure the hydrophilicity of the non-image area, the support (1) was subjected to a silicate treatment at 60 ° C. for 10 seconds using an aqueous 2.5 mass% No. 3 sodium silicate solution, and then washed with water for support. Body (2) was obtained. The adhesion amount of Si was 10 mg / m ² . The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support (2) so that the dry coating amount is 20 mg / m ² , and used in the following experiments. A support having the following structure was prepared.

<Undercoat layer coating solution (1)>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

(3) Formation of image recording layer The image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer formed as described above, and then oven-dried at 100 ° C for 60 seconds to obtain a dry coating amount. An image recording layer of 1.0 g / m ² was formed.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

<Photosensitive solution (1)>
・ The following binder (1) 0.240g
Infrared absorbing dye (1) [the following structure] 0.030 g
-Radical polymerization initiator (1) [the following structure] 0.162 g
-Radical polymerizable compound Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
-0.112 g of star polymer / oligomer listed in Table 12
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Sensitizing agent Ammonium group-containing polymer [the following structure, reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g

  The structures of the binder (1), the infrared absorbing dye (1), the radical polymerization initiator (1), the phosphonium compound (1), the ammonium group-containing polymer, and the fluorosurfactant (1) are as follows: As shown.

-Synthesis of microgel (1)-
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Chemicals, Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, and 0.1 g of Piionin A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205 manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The microgel solution thus obtained was diluted with distilled water to a solid content concentration of 15% by mass, and this was designated as the microgel (1). When the average particle size of the microgel was measured by a light scattering method, the average particle size was 0.2 μm.

(4) Formation of Protective Layer After the bar coating of the protective layer coating liquid (1) having the following composition was applied on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m. ² protective layers were formed to obtain lithographic printing plate precursors (1) to (8).

<Coating liquid for protective layer (1)>
・ Inorganic layered compound dispersion (1) 1.5 g
・ Polyvinyl alcohol 0.55g
(Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification, saponification degree 99 mol% or more,
Degree of polymerization 300)
・ Polyvinyl alcohol 0.03g
(Kuraray Co., Ltd. PVA-405, saponification degree 81.5 mol%, polymerization degree 500)
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[II] Preparation of lithographic printing plate precursor (A) The lithographic printing plate precursor for Comparative Example 4 was prepared in the same manner as the lithographic printing plate precursor (1) except that the photosensitive solution (1) was changed to the following photosensitive solution (A). (A) was produced.

<Photosensitive solution (A)>
・ The following binder (S1) 0.240g
・ Infrared absorbing dye (1) 0.030g
・ Radical polymerization initiator (1) 0.162g
-Radical polymerizable compound Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Sensitizer Phosphonium compound (1) 0.055g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Sensitizing agent Ammonium group-containing polymer [reduced specific viscosity 44 ml / g] 0.035 g
・ Fluorosurfactant (1) 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

X / Y = 0.67 Mw = 50000
X is the number of repeating units derived from methacrylic acid methoxyethoxyethyl ester Y is the number of repeating units derived from methacrylic acid methyl ester

[III] Evaluation of lithographic printing plate precursor <On-press developability>
The resulting lithographic printing plate precursor was exposed with a Luxel PLASETTER T-6000III manufactured by Fuji Film Co., Ltd. equipped with an infrared semiconductor laser under the conditions of an outer drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi. The exposure image included a solid image and a 50% halftone dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Standard automatic printing of LITHRONE26 using dampening water of Ecology-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (capacity ratio) and space color fusion G (N) manufactured by DIC Graphics Co., Ltd. After dampening water and ink were supplied by the start method and developed on the machine, 100 sheets were printed on Tokishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
The number of print sheets required until on-press development on the printing press in the unexposed area of the image recording layer was completed and no ink was transferred to the non-image area was measured as on-press developability (immediately after). .
The lithographic printing plate precursor stored at 60 ° C. for 3 days was evaluated as on-press developability (after time) in the same manner as described above. The results are shown in Table 12.

<Print durability>
After the on-press developability was evaluated, printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. . The results are shown in Table 12.

[Examples 6 to 9 and Comparative Example 5]
(Preparation of lithographic printing plate precursor)
The following image recording layer coating solution (2) is applied to a brush-polished and phosphoric acid-anodized polyacrylic acid (“PAA”) post-treated aluminum substrate using a winding rod, then And dried for about 90 seconds in a Ranar conveyor oven set at 90 ° C. The dry coating amount obtained was 1.5 g / m ² .

<Image recording layer coating solution (2)>
・ Urethane acrylate 2.48g
・ Copolymer 1 13.53 g
・ Copolymer 2 3.97 g
・ Infrared absorbing dye (2) [the following structure] 0.13 g
・ Polymerization initiator Irgacure250 (Ciba Specialty Chemicals) 0.42g
・ Mercapto-3-triazole 0.18g
・ Byk336 (Byk Chimie) 0.60g
-0.07 g of star polymer / oligomer listed in Table 13
・ N-propanol 61.97 g
・ Ion exchange water 16.65g

The compounds in the above formulation are as follows.
* Urethane acrylate: 80% by weight 2-butanone solution of urethane acrylate obtained by reaction of DESMODUR N100 with hydroxyethyl acrylate and pentaerythritol triacrylate * Copolymer 1: 54 g of n-propanol and 16 g of deionized water The mixture was charged into a 250 mL flask, which was heated to 70 ° C., purged with a steady stream of nitrogen gas, and stirred with a mechanical stirrer. A mixture of 54 g n-propanol, 16 g deionized water, 10 g PEGMA, 4.5 g styrene, 40.5 g acrylonitrile, and 0.32 g VAZO-64 was prepared in a separate beaker, which was then Add dropwise to the 250 mL flask over 30 minutes. After 2.5 hours, 0.16 g of VAZO-64 was added to the reaction mixture. The polymerization reaction lasted for another 2 hours. The resulting polymer solution contained 21% solids by weight of copolymer 1.
* Copolymer 2: 2-butanone (384.1 g) and 8.5 g of PEGMA were charged into a 1 L four neck flask under a nitrogen atmosphere and heated to 80 ° C. A premix of allyl methacrylate (38.0 g) and VAZO-64 (0.3 g) was added at 80 ° C. over 90 minutes. After the addition was complete, an additional 0.13 g of VAZO-64 was added. Thereafter, 0.13 g of VAZO-64 was added twice more. The polymer conversion based on percent nonvolatiles was> 98%.
* PEGMA: Sigma-Aldrich Corp. Poly (ethylene glycol) methyl ether methacrylate available from (St. Louis, Missouri); average Mn-2080 as a 50 wt% aqueous solution.
* VAZO-64: E.E. I. du Pont de Nemours and Co. 2,2′-Azobisisobutyronitrile available from (Wilmington, Delaware).
* Infrared absorbing dye (2):

* IRGACURE 250: 75 wt% propylene carbonate solution of (4-methylphenyl) [4- (2-methylpropyl) phenyl] iodonium hexafluorophosphate available from Ciba Specialty Chemicals (Tarrytown, New York) * Byk 336: Byk-Chemie USA Inc. (Different dimethylpolysiloxane copolymer in 25% by weight xylene / methoxypropyl acetate solution available from (Wallingford, Connecticut)

On the obtained image recording layer, the protective layer coating solution (1) was bar-coated and then oven-dried at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.35 g / m ^2. Lithographic printing plate precursors (9) to (13) were obtained.

(Evaluation of lithographic printing plate precursor)
The obtained lithographic printing plate precursor was evaluated for on-press developability and printing durability by the following methods. The results are shown in Table 13 below.

<On-press developability>
The resulting lithographic printing plate precursor was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotating speed of 210 rpm, and a resolution of 2400 dpi. The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. After supplying dampening water and ink using fountain solution (Tokyo ink Co., Ltd. CDS803 diluted 50 times with tap water) and DIC Graphics Co., Ltd. Space Color Fusion G (N), Printing was started at a printing speed of 6000 sheets per hour.
On-press development was measured as the on-press developability (immediately) after the on-press development of the unexposed portion of the image recording layer on the press was completed and the ink was not transferred to the print paper.
The lithographic printing plate precursor stored at 60 ° C. for 3 days was evaluated as on-press developability (after time) in the same manner as described above.

<Print durability>
If the printing is further continued after ink deposition, the image recording layer gradually wears. Since the wear of the image recording layer has progressed and the ink receptivity has decreased, the ink density on the printing paper begins to decrease. Printing durability was evaluated by the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.

  Comparative Example Compound C-4: KLUCEL M [Hercules Inc. , Aqualon Division (Wilmington, Delaware), a 2% by weight aqueous solution of hydroxypropylcellulose (viscosity: 5.000 mPa · s)

[Examples 10 to 15 and Comparative Example 6]

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

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power supply waveform is electrochemical roughening treatment using a trapezoidal rectangular 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 rectangular wave AC. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.
Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried.
The center line average roughness (Ra) of the support 2 thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Furthermore, after applying the following undercoat layer coating solution (2) with a bar, it was oven-dried at 80 ° C. for 10 seconds to apply a dry coating amount of 10 mg / m ² , and a support having an undercoat layer used in the following experiments The body was made.

<Undercoat layer coating solution (2)>
・ Undercoat layer compound (2) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

(2) Formation of image recording layer On the support provided with the above-mentioned undercoat layer, an image recording layer coating solution (3) having the following composition was bar-coated, followed by oven drying at 70 ° C. for 60 seconds, and a dry coating amount. An image recording layer of 1.1 g / m ² is formed, and a protective layer coating liquid (2) having the following composition is applied thereon using a bar so that the dry coating amount is 0.75 g / m ^2. Then, it was dried at 125 ° C. for 70 seconds to obtain lithographic printing plate precursors (14) to (20).

<Image recording layer coating solution (3)>
・ 0.54g of the following binder (2)
・ The following polymerizable compound (1) 0.48 g
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (2) 0.18 g
・ The following co-sensitizer (1) 0.07 g
・ Ε-phthalocyanine pigment dispersion (1) 0.40 g
[Pigment: 15 parts by mass, allyl methacrylate / methacrylic acid (80/20) copolymer (Mw 50,000) as dispersant: 10 parts by mass, cyclohexanone / methoxypropyl acetate /
1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass]
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt-Fluorosurfactant (1) 0.001 g
-0.04 g of star polymer / oligomer listed in Table 14
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

<Coating liquid for protective layer (2)>
-13.0 g of the following inorganic layered compound dispersion (2)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 1.3 g
-Sodium 2-ethylhexyl sulfosuccinate 0.2g
・ Poly (vinyl pyrrolidone / vinyl acetate = 1/1) Mw 70,000 g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.05g
・ 133g of water

(Preparation of inorganic layered compound dispersion (2))
To 368 g of water, 32 g of synthetic mica (“Somasif ME-100” manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added and dispersed using an homogenizer until the average particle size (laser scattering method) is 0.5 μm. An inorganic layered compound dispersion (2) was obtained.

(Evaluation of lithographic printing plate precursor)

<Exposure and development conditions>
(1) Standard printing plate preparation conditions Each of the above lithographic printing plate precursors (14) to (20) was subjected to imagewise exposure using an 405 nm semiconductor laser having an output of 100 mW at an exposure amount of 300 μJ / cm ² .
Thereafter, the developing solution (1) having the composition described below was used, and development processing was carried out in an automatic developing processor (A) having a structure shown in FIG. The automatic processor is an automatic processor having two rotating brush rolls. As the rotating brush roll, the first brush roll and the polybutylene terephthalate fiber (hair diameter 200 μm, hair length 17 mm). Using a brush roll with an outer diameter of 90 mm implanted with 200 mm / min in the same direction as the conveying direction (peripheral speed 0.94 m / sec at the tip of the brush), the second brush roll is made of polybutylene terephthalate Using a brush roll having an outer diameter of 60 mm in which fibers (hair diameter: 200 μm, hair length: 17 mm) were planted, it was rotated 200 times per minute in the direction opposite to the conveying direction (peripheral speed of the brush tip: 0.63 m / sec). . The planographic printing plate precursor was transported at a transport speed of 100 cm / min.
The developer was showered from the spray pipe with a circulation pump and supplied to the plate surface. The tank capacity of the developer was 10 liters. In this way, standard printing plates (14) to (20) were prepared.

(2) Post-heating printing plate preparation conditions For each of the above lithographic printing plate precursors (14) to (20), after performing imagewise exposure at an exposure amount of 90 μJ / cm ² using a 405 nm semiconductor laser with an output of 100 mW, The lithographic printing plate precursor was placed in an oven within 30 seconds, and hot air was blown to heat the entire surface of the lithographic printing plate precursor, and maintained at 110 ° C. for 15 seconds. Then, within 30 seconds, the same development treatment as that for preparing the standard printing plate was performed to prepare post-heated printing plates (14) to (20).

(3) Conditions for preparing printing plate for sensitivity evaluation For each of the above lithographic printing plate precursors (14) to (20), imagewise exposure was performed using a 405 nm semiconductor laser with an output of 100 mW while changing the exposure amount. Thereafter, development was performed in the same manner as in the standard printing plate preparation conditions, and sensitivity evaluation printing plates (14) to (20) were prepared.

(4) Printing plate preparation conditions for evaluation of developability Each of the above lithographic printing plate precursors (14) to (20) is exposed in the same manner as the standard printing plate preparation conditions, and the transport speed of the lithographic printing plate precursor is changed variously. Except for the above, development processing was performed in the same manner as in the standard printing plate preparation conditions, and printing plates for developing evaluation (14) to (20) were prepared.

(Developer (1))
・ Water 100.00g
・ Benzyl alcohol 1.00g
・ Polyoxyethylene naphthyl ether (oxyethylene average number n = 13) 1.00 g
・ Dioctylsulfosuccinate sodium salt 0.50 g
・ Arabic gum 1.00g
・ Ethylene glycol 0.50g
・ Primary ammonium phosphate 0.05g
・ Citric acid 0.05g
・ Sodium carbonate 1.40g
・ Sodium bicarbonate 0.59g
Adjust the pH of the developer to 9.8 using phosphoric acid and sodium hydroxide

<Printing conditions>
Next, the developed lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etchi solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 ( Capacity ratio)) and DIC Graphics Co., Ltd. Space Color Fusion G (N), and printing was performed at a printing speed of 6000 sheets per hour.

<Evaluation conditions>
Using the lithographic printing plate prepared earlier, sensitivity, developability, stain resistance, printing durability, and processability were evaluated as follows. The results are shown in Table 14.
(1) Sensitivity After printing 100 sheets as described above using the sensitivity evaluation printing plates (14) to (20) and confirming that a printed matter having no ink stains in the non-image area was obtained, 500 sheets were printed. In the total 600th printed matter, the exposure amount (μJ / cm ² ) with no unevenness in the ink density in the image area was measured as sensitivity.
(2) Printing durability Printing is performed as described above using a standard printing plate and a post-heating printing plate, and the number of printed sheets when the ink density (reflection density) on the printing paper is reduced by 0.1 from the start of printing, The printing durability was evaluated.
(3) Developability For the printing plates (14) to (20) for developing property evaluation, the cyan density of the non-image area was measured with a Macbeth densitometer. The transport speed (cm / min) at which the cyan density of the non-image area was equal to the cyan density of the aluminum substrate was determined and defined as developability.
(4) Processability When the lithographic printing plate precursor was developed at 2000 m ² with an automatic processor under the standard printing plate preparation conditions described above, the state of occurrence of debris adhering to the wall of the automatic processor was observed. Observed. The evaluation was ○ when there was no residue, Δ when the level was acceptable, and × when residue was remarkable.
(5) Stainability When 500 sheets were printed as described above using the standard printing plate and the post-heating printing plate, the ink stain generated in the non-image area was visually confirmed. The 500th printed material was evaluated with 10 points when a non-image area having no stain was obtained, and 1 point when the ink was almost adhered and dirty.

[Examples 16 to 24 and Comparative Example 7]

(1) Production of Support 3 Surface treatments (a) to (f) shown below were continuously performed using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm. In addition, after each process and water washing, the liquid was drained with the nip roller.

(A) The aluminum plate was etched at a caustic soda concentration of 26% by mass, an aluminum ion concentration of 6.5% by mass, and a temperature of 70 ° C. to dissolve the aluminum plate at 5 g / m ² . Thereafter, it was washed with water.
(B) A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water.
(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass aqueous nitric acid solution (including 0.5% by mass aluminum ions and 0.007% by mass ammonium ions) at a temperature of 30 ° C. The AC power source was subjected to an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 2 msec until the current value reached a peak from zero and a duty ratio of 1: 1. 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 250 C / cm 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. Thereafter, it was washed with water.
(D) The aluminum plate was spray-etched at 35 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass to dissolve the aluminum plate by 0.2 g / m ² , The removal of the smut component mainly composed of aluminum hydroxide generated during chemical roughening and the edge portion of the generated pit were dissolved to smooth the edge portion. Thereafter, it was washed with water.
(E) A desmut treatment by spraying was performed with a 25% by weight aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.
(F) Anodization was performed for 50 seconds at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), a temperature of 33 ° C., and a current density of 5 (A / dm ² ). Thereafter, it was washed with water. The mass of the anodic oxide film at this time was 2.7 g / m ² .
The surface roughness Ra of the aluminum support 3 thus obtained was 0.27 (measuring instrument: Surfcom manufactured by Tokyo Seimitsu Co., Ltd., stylus tip diameter 2 μm).

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (3) was applied to the aluminum support with a wire bar and dried at 90 ° C for 30 seconds. The coating amount was 10 mg / m ² .

<Undercoat layer coating solution (3)>
-Polymer compound A having the following structure: 0.05 g
・ Methanol 27g
・ Ion exchange water 3g

(3) Formation of Image Recording Layer Next, the following image recording layer coating solution (4) was prepared and applied to the above aluminum support using a wire bar. Drying was performed at 115 ° C. for 34 seconds with a hot air dryer to obtain a lithographic printing plate precursor. The coating amount after drying was 1.4 g / m ² .

<Coating liquid for image recording layer (4)>
・ Phosphonium compound (A-6) 0.077g
・ Infrared absorber (IR-1) 0.074g
-Polymerization initiator (OS-12) 0.280g
・ Additive (PM-1) 0.151g
・ Polymerizable compound (AM-1) 1.00 g
・ Binder (BT-1) 1.00g
・ Ethyl violet (C-1) 0.04g
・ Fluorine-based surfactant 0.015g
(Megafuck F-780-F DIC Corporation)
Methyl isobutyl ketone (MIBK) 30% by mass solution)
-0.030 g of star polymer / oligomer listed in Table 15
・ Methyl ethyl ketone 10.4g
・ Methanol 4.83g
・ 10.4 g of 1-methoxy-2-propanol

  Phosphonium compound (A-6), polymerization initiator (OS-12), infrared absorber (IR-1), additive (PM-1), polymerizable compound (AM-) used in the coating solution for the image recording layer. 1) The structures of the binder polymer (BT-1) and ethyl violet (C-1) are shown below.

（Ｍｗ ４５，０００）

(Mw 45,000)

(4) Formation of protective layer On the surface of the above-mentioned image recording layer, synthetic mica (Somasif ME-100, 8% aqueous dispersion, manufactured by Coop Chemical Co., Ltd.) and polyvinyl alcohol (PVA-205 manufactured by Kuraray Co., Ltd.) And a surfactant (Emulex 710, manufactured by Nippon Emulsion Co., Ltd.) are applied with a wire bar and dried at 125 ° C. for 75 seconds with a hot air dryer. I let you.
The ratio of the content of mica solids / polyvinyl alcohol / surfactant in the coating liquid for protective layer (3) is 16/82/2 (mass%), and the total coating amount is (coating after drying) Amount) was 1.6 g / m ² . Thereby, lithographic printing plate precursors (21) to (30) were obtained.

(5) Evaluation of lithographic printing plate precursor The obtained lithographic printing plate precursor was changed by 0.15 at log E within a range of resolution 2400 dpi, external drum rotation speed 200 rpm, output 0-8 W, using a Trendsetter 800II Quantum manufactured by Creo. Exposed. The exposure was performed under conditions of 25 ° C. and 50% RH. After the exposure, neither heat treatment nor water washing treatment was carried out, and development processing was carried out at a conveyance speed (line speed) of 2 m / min and a development temperature of 30 ° C. using an automatic developing machine LP-1310HII manufactured by FUJIFILM Corporation. The developer used was a 1: 4 water diluted solution of DH-N, the developer replenisher was diluted 1: 1.4 water of FCT-421, and the finisher was 1: 1 of GN-2K manufactured by FUJIFILM Corporation. A water dilution was used.

<Sensitivity>
Using the planographic printing plate obtained as described above, 100 sheets were printed in the same manner as in Example 10, and it was confirmed that a printed matter free from ink stains in the non-image area was obtained. A sheet was printed. In the total 600th printed matter, the exposure amount (mJ / cm ² ) without unevenness in the ink density in the image area was measured as sensitivity.

<Print life>
Printing was continued in the same manner as in Example 10 using a lithographic printing plate (without post-heating) with an output of 8 W obtained by making the plate as described above, and the ink density (reflection density) on the printing paper was higher than that at the start of printing. Also, the printing durability was evaluated based on the number of printed sheets when it was reduced by 0.1.

<Developability>
For the lithographic printing plate precursors (21) to (30), the lithographic printing plate was prepared as described above while changing the conveying speed of the automatic processor, and the cyan density of the non-image area was measured with a Macbeth densitometer. The transport speed (m / min) at which the cyan density of the non-image area was equal to the cyan density of the aluminum substrate was determined and defined as developability.

[Examples 25 to 36 and Comparative Example 8]

(Preparation of lithographic printing plate precursor)
(1) Production of Support 4 An aluminum plate (material JIS A 1050, tempered H16) having a thickness of 0.24 mm is immersed in a 5% by mass sodium hydroxide aqueous solution maintained at 65 ° C. for 1 minute of degreasing treatment. After going, it was washed with water. This degreased aluminum plate was neutralized by immersing it in a 10% by mass hydrochloric acid aqueous solution maintained at 25 ° C. for 1 minute, and then washed with water. Next, this aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds under conditions of 25 ° C. and a current density of 100 A / dm ^{2 in} a 0.3 mass% hydrochloric acid aqueous solution, and then kept at 60 ° C. The desmutting treatment was performed for 10 seconds in a 5% by weight aqueous sodium hydroxide solution. The surface-roughened aluminum plate subjected to desmut treatment was anodized in a 15% by weight sulfuric acid solution at 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute, and further 1% polyvinyl. The support 4 was prepared by performing a hydrophilization treatment at 75 ° C. using an aqueous phosphonic acid solution. When the surface roughness was measured, it was 0.44 μm (Ra display according to JIS B0601).

(2) Formation of image recording layer An image recording layer coating solution (5) having the following composition was bar coated on the support 4 and then oven-dried at 90 ° C. for 60 seconds to obtain a dry coating amount of 1.3 g / m. ^Two image recording layers were formed.

<Image recording layer coating solution (5)>
・ The following binder (3) (Mw: 50,000) 0.04 g
・ The following binder (4) (Mw: 80,000) 0.30 g
-0.17 g of the polymerizable compound (1)
-0.51 g of the following polymerizable compound (2)
・ The following sensitizing dye (2) 0.03 g
・ The following sensitizing dye (3) 0.015 g
・ The following sensitizing dye (4) 0.015 g
-0.13 g of the polymerization initiator (2)
・ Chain transfer agent: Mercaptobenzothiazole 0.01g
・ 0.40 g of the ε-phthalocyanine pigment dispersion (1)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt-Fluorosurfactant (1) 0.001 g
-0.030 g of star polymer / oligomer described in Table 16
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

(3) Formation of protective layer After applying the protective layer coating solution (4) having the following composition on the image recording layer using a bar so that the dry coating amount was 1.2 g / m ² , A protective layer was formed by drying at 125 ° C. for 70 seconds to obtain lithographic printing plate precursors (31) to (43).

<Coating liquid for protective layer (4)>
・ PVA-205 0.658g
(Partially hydrolyzed polyvinyl alcohol, manufactured by Kuraray Co., Ltd., degree of saponification = 86.5-89.5 mol%, viscosity = 4.6-5.4 mPa · s (in 20 ° C., 4 mass% aqueous solution))
・ PVA-105 0.142g
(Completely hydrolyzed polyvinyl alcohol, manufactured by Kuraray Co., Ltd., degree of saponification = 98.0-99.0 mol%, viscosity = 5.2-6.0 mPa · s (in 20 ° C., 4 mass% aqueous solution))
・ Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (Mw 70,000) 0.001g
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002g
・ Water 13g

(Evaluation of lithographic printing plate precursor)

(1) Exposure, development, and printing Image exposure was performed on the above-described lithographic printing plate precursor using a violet semiconductor laser plate setter Vx9600 manufactured by FUJIFILM Electronic Imaging Ltd (equipped with InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW). The image was drawn at a resolution of 2438 dpi using an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., and 50% flat netting was performed with a plate exposure amount of 0.05 mJ / cm ² . The sensitivity measurement sample was exposed by changing the exposure amount of the plate surface.
Next, using the developer (2) having the following composition, post-heating (using the pre-heating portion in FIGS. 3 and 200) at 100 ° C. for 10 seconds in the automatic developing processor (B) having the structure shown in FIG. The development process was carried out at a conveying speed where the immersion time (development time) was 20 seconds. Moreover, it developed by changing immersion time variously for developability evaluation.
Next, the developed lithographic printing plate is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etchi solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 ( Capacity ratio)) and DIC Graphics Co., Ltd. Space Color Fusion G (N), and printing was performed at a printing speed of 6000 sheets per hour.

(Developer (2))
88.6g of water
Nonionic surfactant (W-1) following structure 2.4 g
Nonionic surfactant (W-2) The following structure 2.4 g
Nonionic surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 1.0 g
Phenoxypropanol 1.0g
Octanol 0.6g
N- (2-hydroxyethyl) morpholine 1.0 g
Triethanolamine 0.5g
Sodium gluconate 1.0g
Trisodium citrate 0.5g
Ethylenediaminetetraacetate tetrasodium salt 0.05g
Polystyrene sulfonic acid 1.0g
(Versa TL77 (30% solution), manufactured by Alco chemical)
* Phosphoric acid was added to the developer having the above composition to adjust the pH to 7.0.

(2) Evaluation <Sensitivity>
After printing 100 sheets as described above using a lithographic printing plate made by changing the exposure amount of the plate surface, it was confirmed that a printed matter without ink stains was obtained in the non-image area, and then printing 500 sheets Went. In the total 600th printed matter, the exposure amount (μJ / cm ² ) with no unevenness in the ink density in the image area was measured as sensitivity.

<Developability>
Examine the non-image part of the lithographic printing plate exposed at the plate surface exposure amount obtained in the sensitivity evaluation and changed the transport speed so that the developer immersion time can be changed, and there is no residual image recording layer. The developability was evaluated based on the conveyance speed (cm / min) at which good developability was obtained.

<Print durability>
When the number of prints is increased by continuously printing the lithographic printing plate exposed and prepressed with the plate exposure amount obtained in the sensitivity evaluation, the image of the image recording layer formed on the lithographic printing plate gradually wears out and accepts ink. As a result, the ink density of the image on the printing paper decreases. Therefore, the printing durability was evaluated based on the number of printed sheets when the ink density (reflection density) was reduced by 0.1 from the start of printing.

61 Rotating Brush Roll 62 Receiving Roll 63 Conveying Roll 64 Conveying Guide Plate 65 Spray Pipe 66 Pipe Line 67 Filter 68 Plate Feeding Stand 69 Discharge Plate 70 Developer Tank 71 Circulating Pump 72 Plate

DESCRIPTION OF SYMBOLS 11: Conveyance path 200: Preheating (preheating) part 300: Developing part 400: Drying part 202: Machine frame 204: Heating part 208: Heating chamber 210: Skewer roller 212: Carrying inlet 214: Heater 216: Circulation fan 304: Insertion roller pair 306: Processing tank 306a: Edge of processing tank 308: Developer tank (filled with developer)
310: outer panel 312: slit-like insertion port 316: liquid roller pair 318: carry-out roller pair 322: brush roller pair 324: shielding lid 326: brush roller pair 330: spray pipe (* sucked by a pump not shown) (The developer in the developing tank 308 is supplied, and this developer is ejected from the spray pipe 330 into the developing tank 308.)
334: slit-shaped insertion port 336: liquid temperature sensor 338: liquid level meter 332: partition plate 342: guide member 344: guide roller 402: support roller 404: discharge port 406: transport roller pair 408: transport roller pair 410, 412 : Duct 414: Slit hole 50: External tank (developer storage)
52: Upper limit liquid level meter 53: Lower limit liquid level meter 54: Filter unit 55: Developer supply pump C1: First circulation pipe C2: Second circulation pipe 71: Replenishment water tank (water storage)
72: Water replenishment pump C3: Water replenishment piping

Claims (15)

  A lithographic printing plate precursor having an image recording layer containing a hydrophobic binder, a radical polymerizable compound, a radical polymerization initiator, and at least one selected from a star polymer and an oligomer having a hydrophilic group on a support.   The lithographic printing plate precursor as claimed in claim 1, wherein the hydrophilic group is at least one selected from an alkylene oxide group, a sulfonic acid group or a salt thereof, an amide group, and a betaine group.   The lithographic printing plate precursor as claimed in claim 1 or 2, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group has a branched structure of 3 branches or more and 10 branches or less.   The lithographic printing according to any one of claims 1 to 3, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group is branched from the central skeleton via a sulfide bond. Version original edition.   At least one selected from a star polymer and an oligomer having a hydrophilic group has an acid group from the central skeleton via a sulfide bond obtained by polymerizing an ethylenically unsaturated monomer in the presence of a polyfunctional thiol. The lithographic printing plate precursor as claimed in claim 4, wherein the polymer chain is branched from 3 branches to 10 branches.   The lithographic printing plate precursor as claimed in any one of claims 1 to 5, wherein at least one selected from a star polymer and an oligomer having a hydrophilic group has a crosslinkable group.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the hydrophobic binder has an acid group, is insoluble in water, and is soluble in an alkaline aqueous solution.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the hydrophobic binder is insoluble in water and has a polyoxyethylene chain.   The lithographic printing plate precursor as claimed in claim 7 or 8, wherein the hydrophobic binder has a crosslinkable group.   The image can be printed by supplying printing ink and fountain solution after removing the image with a laser to remove the image recording layer in the unexposed area. The lithographic printing plate precursor as described in the paragraph.   The lithographic printing plate precursor as claimed in any one of claims 1 to 9, wherein the image recording layer in the unexposed area can be removed with a developer having a pH of 2 to 14.   12. The lithographic printing plate precursor as claimed in claim 11, wherein the image recording layer and the protective layer in the unexposed area can be removed by a one bath developer.   11. A lithographic printing method comprising printing the lithographic printing plate precursor according to claim 10 after exposing the image with a laser and then supplying printing ink and fountain solution to remove the image recording layer in the unexposed area.   A plate making method of a lithographic printing plate, comprising subjecting the lithographic printing plate precursor according to claim 11 to image exposure with a laser, and then removing an unexposed image recording layer with a developer having a pH of 2 to 14.   A method for making a lithographic printing plate, comprising subjecting the lithographic printing plate precursor according to claim 12 to image exposure with a laser, and then removing an image recording layer and a protective layer in an unexposed portion with a developing solution in one bath.

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