JP2010060935A - Negative lithographic printing plate precursor and plate making method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative lithographic printing plate precursor which cures with high sensitivity upon infrared laser exposure and has a wide heating latitude in preheat treatment, and which even when preheat-treated at a low temperature, can form an image and suppresses the occurrence of a residual film in a non-image area. <P>SOLUTION: The negative lithographic printing plate precursor has on a support an image recording layer containing (A) a compound which is decomposed under light or heat to generate an acid, (B) a crosslinking agent represented by general formula (I), (C) a binder polymer and (D) an infrared absorbent. In the formula, L<SP>1</SP>represents a linking group having a total number of atoms of ≤50; R<SP>1</SP>and R<SP>2</SP>each represent a hydrocarbon group, alkoxy, a halogen atom or nitro; and R<SP>3</SP>and R<SP>4</SP>each represent H or a hydrocarbon group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a negative lithographic printing plate precursor and a plate making method thereof, and more particularly to a negative lithographic printing plate precursor capable of direct plate making using an infrared laser from a digital signal of a computer or the like and a plate making method thereof.

  Conventionally, various systems for directly making a plate from digital data of a computer have been studied, and in particular, a technique for performing exposure using a laser has attracted attention with the recent development of lasers. This laser, particularly a solid-state laser and a semiconductor laser that emits infrared light having a wavelength of 760 nm to 1200 nm, can be easily obtained with high output and small size. These lasers are very useful as a recording light source when directly making a plate from digital data such as a computer. However, since many photosensitive recording materials useful in practical use have a photosensitive wavelength in the visible light range of 760 nm or less, image recording cannot be performed with these infrared lasers. Therefore, a material that can be recorded with an infrared laser is desired.

As such a lithographic printing plate precursor that can be recorded with an infrared laser, an infrared absorber that generates heat upon exposure to the infrared laser, an acid generator that decomposes by heat to generate an acid, and a crosslinking agent that crosslinks with an acid. A lithographic printing plate precursor having a so-called acid-crosslinking type negative image recording layer is known. In such an image forming mechanism of a lithographic printing plate precursor, an infrared absorber generates heat in an infrared laser irradiation region, an acid is generated by heat to cause and advance a crosslinking reaction of the crosslinking agent, and an exposed region is cured to form an image. Forming part.
As a material having an acid cross-linking type negative image forming mechanism, an image recording material using a resol resin as a cross-linking agent and containing a novolac resin, an acid generator and an infrared dye is known (for example, see Patent Document 1). .) Although this material is excellent in sensitivity, storage stability is insufficient, and an undesired curing reaction occurs over time, resulting in print stains, or when a low-temperature heat treatment is performed, a residual film is formed after development. There was a problem.

When making such a lithographic printing plate precursor, it is common to perform preheating treatment before development in order to promote curing of the image area and ensure printing durability.
The preheating treatment improves the crosslink density of the image area and forms an image with excellent printing durability. However, depending on the heat treatment conditions, the unreacted acid generator in the unexposed area is slightly decomposed. As a result, an undesired curing reaction may be caused, and as a result, a remaining film that is not removed by development may be formed in an unexposed area (non-image area).

Excellent thermal stability, especially for the purpose of improving storage stability at high temperatures, it has a polymer with a specific structure, 2 or more hydroxymethyl groups or alkoxymethyl groups, 3-5 benzene nuclei, and molecular weight An acid-crosslinking type negative image forming material using components such as a crosslinking agent of 1200 or less has been proposed (for example, see Patent Document 2). In this material, although the temporal stability during storage has been improved, when preheating treatment is performed, if the heating temperature is too low, the effect of improving the strength of the formed image portion cannot be sufficiently obtained, and When the heating temperature is increased, the image recording layer has high sensitivity, so there is a concern that stains may occur in the non-image area, and it may be difficult to set the heating temperature condition.
For this reason, it cures with high sensitivity by exposure, and in the preheating process, the minimum heating temperature for forming an image area with excellent printing durability is low, and the minimum heating for maintaining excellent developability in the non-image area. Although a material having a high temperature, that is, a wide heating latitude is desired, an image portion having excellent printing durability is formed even in a low-temperature heat treatment, and generation of a residual film in a non-image portion is suppressed. The lithographic printing plate precursor has not been realized yet.
US Pat. No. 5,372,907 US Pat. No. 6,403,283

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, the object of the present invention is to cure with high sensitivity by infrared laser exposure, have a wide heating latitude in preheating treatment, and can form an image portion with excellent printing durability even when preheating treatment is performed at a low temperature. An object of the present invention is to provide a negative lithographic printing plate precursor in which the generation of a residual film in a non-image area is suppressed and a plate making method thereof.

  As a result of intensive studies to achieve the above object, the present inventor has developed a specific structure of a crosslinking component having a physical property that changes from hydrophilic to hydrophobic before and after the reaction to a negative-type image recording layer for infrared rays. The present invention has been completed by finding that the above-mentioned object can be achieved by using.

  That is, the negative lithographic printing plate precursor according to the present invention comprises (A) a compound capable of generating an acid by being decomposed by light or heat on a support, (B) a crosslinking agent represented by the following general formula (I): It is suitably referred to as a specific cross-linking agent], (C) a binder polymer, and (D) an image recording layer containing an infrared absorber.

In the general formula (I), L ¹ is composed of one or more atoms selected from a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, and a sulfur atom, and is a linking group having a total number of atoms of 50 or less. Represents. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a nitro group, which further includes a hydroxyl group, a halogen group, an ether bond, and an amide You may have a bond. n1 and n2 each represent an integer of 0 to 3, but n1 and n2 are not 0 at the same time.
R ³ and R ⁴ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. n3 and n4 each represent an integer of 0 to 3, but n3 and n4 are not 0 simultaneously.
m1 and m2 each represent an integer of 0 to 3, but m1 and m2 are not 0 at the same time.
The crosslinking agent represented by the general formula (I) is preferably a compound represented by the following general formula (I-2).

In the general formula (I-2), L ¹ is a carbon atom, a hydrogen atom, a nitrogen atom, is configured to include one or more atoms selected from oxygen atom and sulfur atom, the total atomic number less 50 Represents a linking group. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a nitro group, which further includes a hydroxyl group, a halogen group, an ether bond, and an amide You may have a bond. R ³ and R ⁴ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.
In addition to the specific crosslinking agent, the image recording layer according to the present invention further includes at least one crosslinking agent selected from a crosslinking agent containing three or more benzene nuclei in the molecule and a resol resin. It is preferable to contain.

  The plate making method of the negative lithographic printing plate precursor according to the present invention includes an exposure step of exposing the negative lithographic printing plate precursor of the present invention positively to the image, and a preheating step of heating at 40 to 200 ° C. after the exposure, And a developing step of removing unexposed portions with an alkali developer.

The effect of the present invention is not clear, but is estimated as follows.
Since the image recording layer of the lithographic printing plate precursor according to the invention contains a specific crosslinking agent having a hydrophilic hydroxyl group and a hydrophobic hydrocarbon group as represented by the general formula (I), exposure is performed. In the region, the hydroxyl group in the molecule disappears due to the formation of a crosslinked structure, and in the cured region, the permeability of the alkaline developer is effectively suppressed due to the influence of the hydrophobic group of the crosslinking agent, and the development resistance is excellent. An image area is formed, and further, the cross-linking density is improved by low-temperature heat treatment, so that the characteristics become more remarkable, and an image area excellent in development resistance and printing durability is formed. Due to the hydrophobic group or specific aromatic ring structure in the specific cross-linking agent, formation of an undesired cross-linking structure is suppressed, and excellent developability due to the hydrophilic group possessed by the specific cross-linking agent No worries about residual film formation Thus, an image recording layer containing this is considered excellent in heat latitude.

  According to the present invention, it is cured with high sensitivity by infrared laser exposure, has a wide heating latitude in preheating treatment, and can form an image portion having excellent printing durability even when preheating treatment is performed at a low temperature, A negative lithographic printing plate precursor capable of suppressing the generation of a residual film in the part and a plate making method thereof can be provided.

The negative lithographic printing plate precursor according to the present invention comprises, on a support, (A) a compound that generates acid upon decomposition by light or heat, (B) a crosslinking agent represented by the general formula (I), and (C) a binder. An image recording layer containing a polymer and (D) an infrared absorber is provided.
Hereinafter, each component of the present invention will be described in detail.
<(B) Crosslinking agent represented by general formula (I) (specific crosslinking agent)>
The image recording layer in the invention contains a compound represented by the following general formula (I) as a crosslinking agent.

In the general formula (I), L ¹ is composed of one or more atoms selected from a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, and a sulfur atom, and is a linking group having a total number of atoms of 50 or less. Represents.
Examples of the linking group represented by L ¹ include a divalent linking group selected from an alkylene group having 1 to 10 carbon atoms, a carbonyl group, —O—, —S—, —NH—, —NHCO—, and the like. Alternatively, a divalent linking group comprising a plurality of these is preferable, and this linking group is further composed of an alkyl group having 1 to 10 carbon atoms, a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 10 carbon atoms. The substituent may be selected, or a plurality of substituents may be bonded to each other to form a ring structure.
Among these, from the viewpoint of the balance between image formability and non-image area stain resistance, the linking group represented by L ¹ is selected from an alkylene group having 1 to 2 carbon atoms, a carbonyl group, and —S—. A divalent linking group is preferred.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a nitro group, and these further have a hydroxy group or a halogen atom as a substituent. Alternatively, the structure may include an ether bond, an amide bond, or the like.
The substitution position of R ¹ and R ² is arbitrary, but from the viewpoint of improving the hydrophobicity of the cured film, it is preferably located at the meta position or ortho position of the linking group represented by L ¹ , more preferably. Is the meta position. From the viewpoint of synthesis suitability, R ¹ and R ² are preferably the same, and both of them are an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and 1 carbon atom. It is preferable that it is -20 alkoxy groups, More preferably, they are a C1-C3 alkyl group, a C6-C12 cycloalkyl group, a phenyl group, etc.
n1 and n2 each represent an integer of 0 to 3, but n1 and n2 are not 0 at the same time. In particular, the case where n1 = n2 = 1 is preferable.

R ³ and R ⁴ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. From the viewpoint of synthesis suitability, R ³ and R ⁴ are preferably the same.
The substitution position of the —CH ₂ —O—R ³ group and —CH ₂ —O—R ⁴ group is arbitrary, but preferably the meta position and the para position, and more preferably the meta position.
n3 and n4 each represent an integer of 0 to 3, but n3 and n4 are not 0 simultaneously. Among these, the case where n1 = n2 = 1 or 2 is preferable, and the case where both are 1 is more preferable.

The substitution position of the —OH group in the general formula (I) is arbitrary, but is preferably ortho-position or para-position, more preferably para-position.
m1 and m2 each represent an integer of 0 to 3, but m1 and m2 are not 0 at the same time. From the viewpoint of synthesis suitability, both are preferably the same, and more preferably m1 = m2 = 1.

  The crosslinking agent represented by the general formula (I) is preferably a compound represented by the following general formula (I-2).

In the general formula (I-2), L ¹ , R ¹ , R ² , R ³ and R ⁴ have the same meanings as in the general formula (I), and preferred examples thereof are also the same.
Specific examples of the specific crosslinking agent that can be suitably used in the present invention [Exemplary compounds [BL-1] to [BL-11]] are shown below, but the present invention is not limited thereto.

Among the above exemplified compounds, [BL-1], [BL-2], [BL-3], [BL-4], [BL from the viewpoint of the balance between image forming property and non-image area stain resistance. −5], [BL-6], [BL-7], [BL-11] and the like are preferable.
The image recording layer according to the present invention may contain only one kind of specific crosslinking agent or two or more kinds in combination.
The content of the specific crosslinking agent in the image recording layer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, from the viewpoint of a balance between image formability and resistance to non-image area contamination. .

<Other cross-linking agents>
In the image recording layer according to the present invention, in addition to the specific cross-linking agent, another cross-linking agent having a structure different from that of the specific cross-linking agent can be used in combination as long as the effects of the present invention are not impaired.
The crosslinking agent that can be used in the present invention (B) has a structure different from that of the crosslinking agent represented by the general formula (I), and is not particularly limited, and any known crosslinking agent can be arbitrarily selected. From the viewpoint of effects, (B-1) a crosslinking agent containing three or more benzene nuclei in the molecule and (B-2) a crosslinking agent selected from a resole resin are preferable.

(B-1) Crosslinking agent containing 3 or more benzene nuclei in the molecule The crosslinking agent containing 3 or more benzene nuclei in the molecule used in the present invention was substituted with an alkoxymethyl group or a hydroxymethyl group. Preferable examples include aromatic compounds that have a hydroxymethyl group or an alkoxymethyl group at a position adjacent to a hydroxy group, and have at least three aromatic rings.
Preferable examples include compounds represented by the following general formulas (1) to (4).

In the above formulas, L _{1 to} L ₈ each independently represent a hydroxymethyl group or an alkoxymethyl group substituted with an alkoxy group having 18 or less carbon atoms such as methoxymethyl, ethoxymethyl and the like.
Examples of such compounds include the compounds described in paragraphs [0133] to [0140] of JP-A No. 10-29292, and specific examples thereof include the following compounds.

(B-2) Resol resin The resol resin that can be used in the present invention is not particularly limited, and is a resinous resin containing a hydroxymethyl group obtained by polycondensation of phenols and aldehydes under basic or weakly acidic conditions. Any compound can be used. Specifically, it is a resol resin obtained by polycondensing a phenol resin such as phenol, cresol, alkylphenol, xylenol, bisphenol A, bisphenol F, or bisphenol S and an aldehyde under basic conditions. Is preferred.
For example, compounds disclosed as resole resins in British Patent 2,082,339, US Pat. No. 5,372,907, and the like can also be used in the present invention.
Preferred examples of the resole resin include those having a weight average molecular weight of 500 to 100,000 and a number average molecular weight of 200 to 50,000. Within the above molecular weight range, good crosslinkability is obtained, and there is no concern about deterioration in storage stability over time.

  These “other cross-linking agents” are preferable in that they are used in combination with the specific cross-linking agent according to the present invention in that the cross-linking efficiency is high and the printing durability can be improved. The other crosslinking agents exemplified above may be used alone or in combination of two or more.

The other crosslinking agent that can be used in the present invention can be used in the range of 0 to 300 parts by mass, preferably in the range of 0 to 100 parts by mass, with respect to 100 parts by mass of the specific crosslinking agent. .
The content of the crosslinking agent in the image recording layer of the present invention is preferably 5 to 90% by mass as the total amount of the specific crosslinking agent and the other crosslinking agent with respect to the total solid content of the image recording layer. More preferably, it is mass%. When the total amount of the crosslinking agent is within the above range, both the printing durability at the time of curing the image recording layer and the stability at the time of storage are good.

Hereinafter, other components contained in the image recording layer according to the present invention will be described.
<(A) Compound that decomposes by light or heat to generate acid>
In the present invention, the compound that generates an acid by being decomposed by light or heat (hereinafter, appropriately referred to as an acid generator) is a compound that generates an acid upon irradiation with light having a wavelength of 200 to 500 nm or heating at 100 ° C. or higher. Point to. As an acid generator suitably used in the present invention, it is used for a photoinitiator for photocationic polymerization, a photoinitiator for radical photopolymerization, a photodecolorant for dyes, a photochromic agent, a microresist, or the like. Known compounds such as known acid generators, which generate acid upon thermal decomposition, and mixtures thereof can be appropriately selected and used.

  For example, S.M. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. The diazonium salt described in Bal et al, Polymer, 21, 423 (1980), U.S. Pat. Nos. 4,069,055, 4,069,056, Re27,992, and JP-A-4-365049. Ammonium salts described in the C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad, Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent Nos. 104 and 143, U.S. Pat. Nos. 339,049 and 410,201, JP-A-2-150848 and JP-A-2-296514, . V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer

Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 2877 (1979), European Patent Nos. 370,693, 390,214, 233,567, 297,443, 297,442, U.S. Pat. No. 4,933,377, 161,811, 410,201, 339,049, 4,760,013, 4,734,444, 2,833,827, German Patent 2,904 No. 626, No. 3,604,580, No. 3,604,581

J. et al. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt, C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), onium salts such as arsonium salts, U.S. Pat. No. 3,905,815, Japanese Examined Patent Publication No. 46-4605, Japanese Unexamined Patent Publication No. 48-36281, Japanese Unexamined Patent Publication No. Sho 55-. 32070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62-58241, JP 62-212401, JP 63-70243 Organic halogen compounds described in JP-A-63-298339, K.I. Meier et al, J.A. Rad. Curing, 13 (4), 26 (1986), T.A. P. Gill et al, Inorg. Chem. , 19, 3007 (1980), D.M. Astruc, Acc. Chem. Res. , 19 (12), 377 (1896), and organic metal / organic halides described in JP-A-2-161445; Hayase et al, J.A. Polymer Sci. 25, 753 (1987), E.I. Reichmanis et al. Polymer Sci. , Polymer Chem. Ed. , 23, 1 (1985), Q.M. Q. Zhu et al, J Photochem. 36, 85, 39, 317 (1987), B.R. Amit
et al, Tetrahedron Lett. , (24) 2205 (1973),

D. H. R. Barton et al, J.A. Chem. Soc. 3571 (1965), p. M.M. Collins et al, J.A. Chem. Soc. Perkin I, 1695 (1975), M .; Rudinstein et al, Tetrahedron Lett. , (17), 1445 (1975), J. MoI. W. Walker et al, J. et al. Am. Chem. Soc. 110, 7170 (1988), S.A. C. Busman et al, J.M. Imaging Technol. 11 (4), 191 (1985), H. et al. M.M. Houlihan et al, Macromolecules, 21, 2001 (1988), p. M.M. Collins et al, J.A. Chem. Soc. , Chem. Commun. 532 (1972), S.A. Hayase et al, Macromolecules, 18, 1799 (1985); Reichmanis et al. Electrochem. Soc. , Solid
State Sci. Technol. , 130 (6), F.M. M.M. Houlihan et al, Macromolecules, 21, 2001 (1988), European Patent Nos. 0290,750, 046,083, 156,535, 271,851, 0,388,343, US Patent No. No. 3,901,710, 4,181,531, JP-A-60-198538, JP-A-53-133022, photoacid generator having an o-nitrobenzyl type protecting group, M.I. Tunooka et al, Polymer Preprints Japan, 38 (8), G.M. Berner et al, J.A. Rad. Curing, 13 (4), W.M. J. et al. Mijs et al, Coating Technol. , 55 (697), 45 (1983), Akzo, H .; Adachi et al, Polymer Preprints, Japan, 37 (3), European Patent Nos. 0199,672, 84515, 199,672, 044,115, 0101,122, US Pat. No. 4,618 No. 5,564, No. 4,371,605, No. 4,431,774, JP-A No. 64-18143, JP-A No. 2-245756, JP-A No. 3-140109, and the like. Examples thereof include a compound that generates a sulfonic acid by photolysis and a disulfone compound described in JP-A No. 61-166544.

Further, these acid-generating groups or compounds in which a compound is introduced into the main chain or side chain of the polymer, for example, M.P. E. Woodhouse et al., J. MoI. Am. Chem. Soc. 104, 5586 (1982), S .; P. Pappas
et al, J. et al. Imaging Sci. , 30 (5), 218 (1986), S .; Kondo et al. Makromol. Chem. , Rapid Commun. , 9, 625 (1988), Y. et al. Yamada et al, Makromol. Chem. 152, 153, 163 (1972), J. Am. V. Crivello et al. J. et al. Polymer Sci. , Polymer Chem. Ed. , 17, 3845 (1979), U.S. Pat. No. 3,849,137, German Patent 3,914,407, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263. And compounds described in JP-A-63-146037, JP-A-63-163452, JP-A-62-153853, and JP-A-63-146029 can be used.

  Further, V.V. N. R. Pillai, Synthesis, (1), 1 (1980), A.M. Abad et al, Tetrahedron Lett. , (47) 4555 (1971), D.M. H. R. Barton et al, J.A. Chem, Soc,. (C), 329 (1970), U.S. Pat. No. 3,779,778, European Patent 126,712 and the like, compounds that generate an acid by light can also be used.

  The acid generator is preferably an onium salt having a halide or sulfonic acid as a counter ion, and examples of the onium salt include iodonium salts, diazonium salts, and sulfonium salts. Examples of onium salts preferably used in the present invention include iodonium salts represented by the following general formula (II), sulfonium salts represented by the general formula (III), and diazonium represented by the general formula (IV). Salt. Of these onium salts, diazonium salts are particularly preferred as the acid generator.

In the general formulas (II) to (IV), X ⁻ represents a halide ion, ClO ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ , or R ⁷ —SO ₃ ^— , where R ⁷ Represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Ar ¹¹ and Ar ¹² each independently represent an aryl group having 20 or less carbon atoms, which may have a substituent. R ¹¹ , R ¹² , and R ¹³ represent a hydrocarbon group having 18 or less carbon atoms, which may have a substituent.

In formula (II) ~ (IV), X - as a, R ⁷ -SO ₃ ^- is particularly preferable. R ⁷ represents an optionally substituted hydrocarbon group having 20 or less carbon atoms. Specific examples of the hydrocarbon group represented by R ⁷ include a methyl group, an ethyl group, an n-propyl group, alkyl groups such as i-propyl group, allyl group, n-butyl group, sec-butyl group, t-butyl group, hexyl group, cyclohexyl group, octyl group, 2-ethylhexyl group, dodecyl group; vinyl group, 1-methyl group Alkenyl groups such as vinyl group and 2-phenylvinyl group; aralkyl groups such as benzyl group and phenethyl group; phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, dodecylphenyl group, phenylphenyl group, naphthyl group, anthracenyl group And aryl groups such as groups.

The hydrocarbon group represented by R ⁷ is, for example, a substituent such as a halogen atom, hydroxy group, alkoxy group, allyloxy group, nitro group, cyano group, carbonyl group, carboxyl group, alkoxycarbonyl group, anilino group, acetamide group, etc. You may have. Specific examples of the hydrocarbon group having a substituent include trifluoromethyl group, 2-methoxyethyl group, 10-camphanyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, iodophenyl group, methoxyphenyl group, hydroxy Examples thereof include a phenyl group, a phenoxyphenyl group, a nitrophenyl group, a cyanophenyl group, a carboxyphenyl group, a methoxynaphthyl group, a dimethoxyanthracenyl group, a diethoxyanthracenyl group, and an anthraquinonyl group.

Ar ¹¹ and Ar ¹² each independently represents an aryl group having 20 or less carbon atoms which may have a substituent, specifically, a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, Dodecylphenyl group, phenylphenyl group, naphthyl group, anthracenyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, iodophenyl group, methoxyphenyl group, hydroxyphenyl group, phenoxyphenyl group, nitrophenyl group, cyanophenyl group, carboxy Examples thereof include a phenyl group, anilinophenyl group, anilinocarbonylphenyl group, morpholinophenyl group, phenylazophenyl group, methoxynaphthyl group, hydroxynaphthyl group, nitronaphthyl group, anthraquinonyl group and the like.

R ¹¹ , R ¹² , and R ¹³ each independently represent a hydrocarbon group having 18 or less carbon atoms that may have a substituent, specifically, a methyl group, an ethyl group, or an n-propyl group. I-propyl group, allyl group, n-butyl group, sec-butyl group, t-butyl group, hexyl group, cyclohexyl group, benzyl group, phenyl group, tolyl group, t-butylphenyl group, naphthyl group, anthracenyl group Hydrocarbon group such as 2-methoxyethyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, iodophenyl group, methoxyphenyl group, hydroxyphenyl group, phenylthiophenyl group, hydroxynaphthyl group, methoxynaphthyl group, benzoyl Examples thereof include a hydrocarbon group having a substituent such as a methyl group and a naphthoylmethyl group.
R ¹¹ and R ¹² may be bonded to each other to form a ring.

  In the present invention, preferred specific examples of the onium salt suitably used as the acid generator are shown below, but are not limited thereto.

An acid generator may be used independently and may use 2 or more types together.
The acid generator is preferably 0.01 to 50% by mass, more preferably 0.1 to 25% by mass, and still more preferably 0.5 to 20% by mass with respect to the total solid content of the image recording layer. It is contained in the image recording layer. When the addition amount is in the above range, good image forming properties can be obtained, and the occurrence of smearing in non-image areas can be suppressed.

<(C) Binder polymer>
The image recording layer contains a binder polymer from the viewpoint of improving film properties.
The binder polymer is preferably an alkali-soluble resin, and examples of the alkali-soluble resin include novolak resins and polymers having a hydroxyaryl group in the side chain.
The novolak resin that can be used as the alkali-soluble resin in the present invention is a resin obtained by condensing phenols and aldehydes under acidic conditions.
Preferred novolak resins include, for example, novolak resins obtained from phenol and formaldehyde, novolak resins obtained from m-cresol and formaldehyde, novolak resins obtained from p-cresol and formaldehyde, novolak resins obtained from o-cresol and formaldehyde, and octylphenol. And novolak resins obtained from formaldehyde, m- / p-mixed cresol and novolak resins obtained from formaldehyde, phenol / cresol (m-, p-, o- or m- / p-, m- / o-, o- / P-mixed) and a novolak resin obtained from formaldehyde.
These novolak resins preferably have a weight average molecular weight of 800 to 200,000 and a number average molecular weight of 400 to 60,000.

Moreover, as an alkali-soluble resin in this invention, the polymer which has a hydroxyaryl group in a side chain can also be mentioned preferably.
In this polymer, the hydroxyaryl group refers to an aryl group having one or more —OH groups bonded thereto. Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthrenyl group, and a phenyl group or a naphthyl group is preferable from the viewpoint of availability and physical properties. Accordingly, the hydroxyaryl group is preferably a hydroxyphenyl group, a dihydroxyphenyl group, a trihydroxyphenyl group, a tetrahydroxyphenyl group, a hydroxynaphthyl group, a dihydroxynaphthyl group, or the like. These hydroxyaryl groups may further have a substituent such as a halogen atom, a hydrocarbon group having 20 or less carbon atoms, an alkoxy group having 20 or less carbon atoms, and an aryloxy group having 20 or less carbon atoms. Good. These hydroxyaryl groups are bonded to the polymer main chain in a pendant form as a side chain of the polymer, but may have a linking group between them.

  The polymer having a hydroxyaryl group in the side chain preferably used in the present invention is a polymer containing any one of the structural units represented by the following general formulas (A) to (D).

In the general formulas (A) to (D), R ¹¹ represents a hydrogen atom or a methyl group. R ¹² and R ¹³ may be the same or different, and are a hydrogen atom, a halogen atom, a hydrocarbon group having 10 or less carbon atoms, an alkoxy group having 10 or less carbon atoms, or an aryloxy group having 10 or less carbon atoms. Indicates. R ¹² and R ¹³ may be bonded to each other to form a condensed benzene ring or cyclohexane ring. R ¹⁴ represents a single bond or a divalent hydrocarbon group having 20 or less carbon atoms. R ¹⁵ represents a single bond or a divalent hydrocarbon group having 20 or less carbon atoms. R ¹⁶ represents a single bond or a divalent hydrocarbon group having 10 or less carbon atoms. X ¹ represents a single bond, an ether bond, a thioether bond, an ester bond or an amide bond. p shows the integer of 1-4. q and r each represents an integer of 0 to 3.

  Among the structural units represented by the general formulas (A) to (D), examples of specific structural units suitably used in the present invention are listed below.

These polymers can be synthesized by a conventionally known method.
For example, a polymer having a structural unit represented by the general formula (A) can be deprotected after a hydroxy group is protected as an acetate ester or t-butyl ether to form a polymer by radical polymerization or anion polymerization of the corresponding styrene derivative. Can be obtained.
Moreover, the polymer which has a structural unit represented by general formula (B) is compoundable by the method described in Unexamined-Japanese-Patent No. 64-32256, 64-35436, etc.
Furthermore, the polymer having the structural unit represented by the general formula (C) can be obtained by reacting an amine compound having a hydroxy group with maleic anhydride to obtain a corresponding monomer, and then forming the polymer by radical polymerization. .
The polymer having the structural unit represented by the general formula (D) is derived from a styrene having a functionally useful functional group such as chloromethylstyrene or carboxystyrene to a monomer corresponding to the general (D). Further, it can be obtained by forming a polymer by radical polymerization.

In the present invention, it may be a homopolymer consisting only of the structural units represented by the general formulas (A) to (D), but may also be a copolymer including other structural units.
Other structural units that can be suitably used include, for example, acrylic esters, methacrylic esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylic acid, methacrylic acid, acrylonitrile, maleic anhydride, maleic Examples thereof include structural units introduced from known monomers such as acid imides.

  Specific examples of acrylates that can be used include methyl acrylate, ethyl acrylate, (n- or i-) propyl acrylate, (n-, i-, sec- or t-) butyl acrylate, amyl acrylate, 2 -Ethylhexyl acrylate, dodecyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 5-hydroxypentyl acrylate, cyclohexyl acrylate, allyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl Acrylate, methoxybenzyl acrylate, chlorobenzyl acrylate, 2- (p-hydroxyphenyl) ethyl acetate Rate, furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, chlorophenyl acrylate, sulfamoylphenyl acrylate and the like.

  Specific examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, (n- or i-) propyl methacrylate, (n-, i-, sec- or t-) butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, Dodecyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 5-hydroxypentyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, methoxybenzyl methacrylate, chloro Benzyl methacrylate, 2- (p-hydroxyphenyl) ethyl methacrylate Rate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, chlorophenyl methacrylate, sulfamoylphenyl methacrylate and the like.

  Specific examples of acrylamides include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, and N-tolylacrylamide. N- (p-hydroxyphenyl) acrylamide, N- (sulfamoylphenyl) acrylamide, N- (phenylsulfonyl) acrylamide, N- (tolylsulfonyl) acrylamide, N, N-dimethylacrylamide, N-methyl-N- Examples include phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, and the like.

  Specific examples of methacrylamides include methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, N-benzylmethacrylamide, N-hydroxyethylmethacrylamide, N -Phenylmethacrylamide, N-tolylmethacrylamide, N- (p-hydroxyphenyl) methacrylamide, N- (sulfamoylphenyl) methacrylamide, N- (phenylsulfonyl) methacrylamide, N- (tolylsulfonyl) methacrylamide N, N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-hydroxyethyl-N-methylmethacrylamide and the like.

Specific examples of vinyl esters include vinyl acetate, vinyl butyrate, vinyl benzoate and the like.
Specific examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, propyl styrene, cyclohexyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, methoxy styrene, dimethoxy styrene. Chlorostyrene, dichlorostyrene, bromostyrene, iodostyrene, fluorostyrene, carboxystyrene and the like.

  Among these monomers, particularly preferably used are acrylic acid esters having 20 or less carbon atoms, methacrylic acid esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylic acid, methacrylic acid, Acrylonitrile.

  Among these monomers, particularly preferably used are acrylic acid esters having 20 or less carbon atoms, methacrylic acid esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylic acid, methacrylic acid, Acrylonitrile.

The proportion of the structural units represented by the general formulas (A) to (D) contained in the copolymer using these is preferably 5 to 100% by mass, more preferably 10 to 100% by mass. is there.
The molecular weight of the polymer used in the present invention is preferably 4000 or more in terms of weight average molecular weight, more preferably in the range of 10,000 to 300,000, and preferably 1000 or more in terms of number average molecular weight, more preferably. It is in the range of 2000-250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, and more preferably 1.1 to 10.
These polymers may be random polymers, block polymers, graft polymers or the like, but are preferably random polymers.

The binder polymer used in the present invention may be used alone or in combination of two or more.
The content of the binder polymer is preferably 5 to 95% by mass, more preferably 10 to 95% by mass, and still more preferably 20 to 90% by mass in the total solid content of the image recording layer, from the viewpoint of durability of the image recording layer. %.

<(D) Infrared absorber>
The infrared absorber used in the present invention is a dye or pigment that effectively absorbs infrared rays having a wavelength of 760 nm to 1200 nm. A dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.
As the dye, commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by Organic Synthetic Chemical Society, 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 Is mentioned.
Preferred dyes include cyanine dyes described in, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787, and JP-A-58- No. 173696, JP-A-58-181690, JP-A-58-194595, etc., methine dyes, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187 Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, etc., UK Examples thereof include cyanine dyes described in Japanese Patent No. 434,875.

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

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Furthermore, cyanine dyes and indolenine cyanine dyes are preferred. In particular, the cyanine dye represented by the following general formula (a) is most preferable when used in the recording layer in the invention because it gives high polymerization activity and is excellent in stability and economy.

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —N (Ar ^X ) ₂ , X ² -L ¹ or a group shown below. Here, Ar ^X represents an aromatic hydrocarbon group having 6 to 14 carbon atoms, and this aromatic hydrocarbon group includes a halogen atom, an alkyl group, an allyl group, an alkenyl group, an alkynyl group, a cyano group, a carboxy group, a nitro group, One or more substituents selected from the group consisting of a group, an amide group, an ester group, an alkoxy group, an amino group, and a heterocyclic group, and these substituents may be substituted with the substituents. It may be. X ² represents an oxygen atom, a sulfur atom, or —N (R ^X ) —, and R ^X represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. 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 above formula, Xa ^- has Za described later ^- is defined as in, 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 recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

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

Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.
Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used. Among these pigments, carbon black is preferable.

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

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the particle diameter of the pigment is less than 0.01 μm, it is not preferable from the viewpoint of stability of the dispersion in the photosensitive layer coating solution, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image recording layer.
As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

These infrared absorbers are 0.01 to 50% by weight, preferably 0.1 to 10% by weight, based on the total solid content of the image recording layer. In this case, it can be particularly preferably added to the image recording layer at a ratio of 1.0 to 10% by mass.
When the addition amount of the pigment or dye is within the above range, an image can be formed with high sensitivity, and the occurrence of stains in the non-image area is effectively suppressed.
These dyes or pigments may be added to the same layer as other components, or another layer may be provided and added thereto.

<Other ingredients>
In the present invention, various compounds may be added as necessary in addition to the components essential for the image recording layer.
For example, a dye having a large absorption in the visible light region can be used as an image colorant.
Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI52015), etc., or JP-A-62-293247 And dyes described in Japanese Patent Publication No.
These dyes are preferably added after image formation because they can be easily distinguished from image portions and non-image portions. The amount added is 0.01 to 10% by mass with respect to the total solid content of the image recording layer.

In the image recording layer of the present invention, nonionic surface activity as described in JP-A Nos. 62-251740 and 3-208514 is used in order to increase the processing stability against development conditions. An amphoteric surfactant as described in JP-A-59-121044 and JP-A-4-13149 can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.
Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and N-tetradecyl-N, N- Examples include betaine type (for example, trade name Amorgen K, manufactured by Daiichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and amphoteric surfactant in the image recording layer is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

Furthermore, a plasticizer is added to the image recording layer in the present invention, if necessary, in order to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid oligomer And polymers are used.
Besides these, epoxy compounds, vinyl ethers, and the like may be added.

The image recording layer of the present invention can be usually produced by dissolving each of the above components in a solvent and coating the solution on a suitable support. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, it is not limited to this. These solvents are used alone or in combination. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
Further, the coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally speaking, 0.5 to 5.0 g / m ² for the image recording layer of the lithographic printing plate precursor. preferable.
Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the image recording film deteriorate.

  In the image recording layer of the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant described in JP-A-62-170950 may be added. it can. A preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass in the total solid content of the image recording layer.

<Support>
As the support in the negative planographic printing plate precursor of the present invention, it is preferable to use a support that has been subjected to a hydrophilic treatment as described below.
Examples of such a support include paper, polyester film, and aluminum plate. Among them, a surface having good dimensional stability, relatively inexpensive, and excellent hydrophilicity and strength by surface treatment as required. An aluminum plate that can be provided is more preferred. A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in Japanese Patent Publication No. 48-18327 is also preferable.

  The aluminum plate as the most preferable support in the present invention is a metal plate mainly composed of dimensionally stable aluminum, and contains pure aluminum plate, aluminum as a main component, and a trace amount of foreign elements. An alloy plate or aluminum (alloy) is selected from laminated or vapor-deposited plastic film or paper. In the following description, the above-mentioned support made of aluminum or aluminum alloy is used generically as an aluminum support. Examples of the foreign element contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is 10% by mass or less. In the present invention, a pure aluminum plate is suitable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. Thus, the composition of the aluminum plate applied to the present invention is not specified, and a conventionally known publicly available material such as JIS A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. It can be used as appropriate.

Moreover, the thickness of the aluminum support body used for this invention is about 0.1 mm-about 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's desire.
Such an aluminum support is subjected to a surface treatment described later to be hydrophilized.

[Roughening treatment]
Examples of the roughening treatment method include mechanical roughening, chemical etching, and electrolytic grain as disclosed in JP-A-56-28893. Furthermore, an electrochemical surface roughening method in which the surface of the aluminum surface is electrochemically roughened in hydrochloric acid or nitric acid electrolyte, and the aluminum surface is ground with a metal wire, and the aluminum brush surface is polished with a polishing ball and an abrasive. A mechanical graining method such as a ball graining method or a brush graining method in which the surface is roughened with a nylon brush and an abrasive can be used, and the above roughening methods can be used alone or in combination. Among them, a method usefully used for roughening is an electrochemical method in which roughening is chemically roughened in hydrochloric acid or nitric acid electrolyte, and a suitable amount of electricity at the time of anode is 50 C / dm ^{2 to} 400 C / dm ² . It is a range. More specifically, in the electrolytic solution containing from 0.1 to 50% hydrochloric acid or nitric acid, the temperature 20 to 80 ° C., for 1 second to 30 minutes, alternating at a current density of 100C ^/ dm ² ~400C ^/ dm 2 It is preferable to perform direct current electrolysis.

  The roughened aluminum support may be chemically etched with acid or alkali. Etching agents suitably used are caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, and the like. Preferred ranges of concentration and temperature are 1 to 50% and 20%, respectively. ~ 100 ° C. Pickling is performed to remove dirt (smut) remaining on the surface after etching. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid and the like are used. In particular, as a method for removing smut after the electrochemical surface roughening treatment, contact with 15 to 65 mass% sulfuric acid at a temperature of 50 to 90 ° C. as described in JP-A-53-12739 is preferable. And the alkali etching method described in Japanese Patent Publication No. 48-28123. After the treatment as described above, the method and conditions are not particularly limited as long as the surface roughness Ra of the treated surface is about 0.2 to 0.5 μm.

[Anodizing treatment]
The aluminum support that has been treated as described above to form an oxide layer is then anodized.
In the anodizing treatment, sulfuric acid, phosphoric acid, oxalic acid, or an aqueous solution of boric acid / sodium borate is used alone or in combination as a main component of the electrolytic bath. In this case, the electrolyte solution may of course contain at least components normally contained in at least an Al alloy plate, an electrode, tap water, groundwater and the like. Further, the second and third components may be added. Here, the second and third components are, for example, metal ions such as Na, K, Mg, Li, Ca, Ti, Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and ammonium ions. Examples include cations, nitrate ions, carbonate ions, chloride ions, phosphate ions, fluorine ions, sulfite ions, titanate ions, silicate ions, borate ions and the like, and the concentration is 0 to 10,000 ppm. May be included. There are no particular limitations on the conditions for the anodizing treatment, but the treatment is preferably carried out by direct current or alternating current electrolysis at a treatment liquid temperature of 10 to 70 ° C. and a current density of 0.1 to 40 A / m ² at 30 to 500 g / liter. . The thickness of the formed anodic oxide film is in the range of 0.5 to 1.5 μm. Preferably it is the range of 0.5-1.0 micrometer. The support produced by the above treatment is treated so that the pore diameter of the micropores existing in the anodized film is in the range of 5 to 10 nm and the pore density is in the range of 8 × 10 ¹⁵ to 2 × 10 ¹⁶ pieces / m ^2. It is preferred that the conditions are selected.

  By making the thickness of the anodic oxide film in the above range, the adhesion with the image recording layer is improved, good printing durability is obtained, and at the time of printing due to scratches in the non-image area, The occurrence of so-called “scratch stains” to which ink adheres can be suppressed, which is preferable.

A widely known method can be applied as the hydrophilic treatment on the surface of the support. As a particularly preferable treatment, a hydrophilic treatment with silicate or polyvinylphosphonic acid is performed. The coating is formed with a Si or P element amount of ^{2 to} 40 mg / m ² , more preferably 4 to 30 mg / m ² . The coating amount can be measured by fluorescent X-ray analysis.

  The hydrophilization treatment is carried out by applying an anodized film to an aqueous solution containing 1 to 30% by weight, preferably 2 to 15% by weight of alkali metal silicate or polyvinylphosphonic acid, and having a pH of 10 to 13 at 25 ° C. This is carried out by immersing the aluminum support on which is formed, for example, at 15 to 80 ° C. for 0.5 to 120 seconds.

  As the alkali metal silicate used for the hydrophilization treatment, sodium silicate, potassium silicate, lithium silicate, or the like is used. Examples of the hydroxide used for increasing the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. In addition, you may mix | blend alkaline-earth metal salt or Group IVB metal salt with said process liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, and barium nitrate, and water-soluble substances such as sulfate, hydrochloride, phosphate, acetate, oxalate, and borate. Salt. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium fluoride titanium, potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, etc. Can be mentioned.

  Alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. A preferable range of these metal salts is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5.0% by mass. Silicate electrodeposition as described in US Pat. No. 3,658,662 is also effective. A support body provided with electrolytic grains as disclosed in JP-B-46-27481, JP-A-52-58602, JP-A-52-30503, and the anodizing treatment and hydrophilization treatment described above A surface treatment combining these is also useful.

Further, a hydrophilic layer as described in JP-A No. 11-231509 can be formed on the anodized support surface.
The coating amount after drying of the hydrophilic ^{layer, 2mg / m 2 ~200mg / m} 2 is is suitable, preferably ^{3mg / m 2 ~60mg / m 2} .

<Plate making of lithographic printing plate precursor>
The lithographic printing plate precursor of the present invention obtained as described above is image-exposed with a solid-state laser and a semiconductor laser that emits infrared light with a wavelength of 760 nm to 1200 nm, thereby curing the exposed portion and developing the non-image portion. An image is formed by removing the image.
When making the lithographic printing plate precursor according to the present invention, for the purpose of improving the curability of the image area and expanding the difference in developability between the image area and the non-image area, the exposure process and the development process by laser irradiation are performed. Pre-heat treatment (heat treatment) is performed.
The heating condition in the preheating treatment is preferably 10 seconds to 5 minutes within the range of 80 ° C. to 160 ° C., and the low temperature heating is more preferably performed within the range of 80 ° C. to 135 ° C. for 10 seconds to 5 minutes. .
At this time, the difference between the lowest temperature at which an image can be formed and the highest temperature at which a residual film is generated is referred to as a heating latitude, and this difference is 15 ° C. or higher. Although it is preferable from a viewpoint, if it is 10 degreeC or more, it can be said that it is a level which is practically satisfactory.
Since the image recording layer of the lithographic printing plate precursor according to the present invention has a good heating latitude as described above, even when heated at a low temperature, a sufficient effect of improving the strength of the image portion can be obtained, and the hydrophobicity of the image portion can be obtained. Therefore, an image having excellent development resistance and printing durability is formed. Further, by performing the low temperature heating, the decomposition of the undesired acid generator in the non-image area is suppressed, and there is no concern that a remaining film is generated in the non-image area.
For this reason, the degree of freedom of the temperature condition in the preheating process is high.
Such preheating treatment can reduce the laser energy required for recording during laser irradiation.

After the preheating treatment, the lithographic printing plate precursor according to the invention is developed with an alkaline aqueous solution.
A conventionally known alkaline aqueous solution can be used as the developer and replenisher that can be used in the development step in the present invention.
Examples of such an alkaline aqueous solution include a developer comprising an alkali silicate or a non-reducing sugar and a base, and those having a pH of 12.5 to 14.0 are particularly preferable. The alkali silicate exhibits alkalinity when dissolved in water, and examples thereof include alkali metal silicates such as sodium silicate, potassium silicate and lithium silicate, and ammonium silicate. The alkali silicate may be used alone or in combination of two or more.

Alkaline aqueous solution, silicon oxide SiO ₂ to alkali oxide is a component of the silicate M _{2 O} (M represents an alkali metal or an ammonium group.) And the mixture ratio, and by adjusting the concentration, easy developability Can be adjusted.
Among the alkaline aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of the silicon oxide SiO ₂ and the alkali oxide M ₂ O of 0.5 to 3.0 are preferably in this range. In addition, a general-purpose aluminum plate is rarely etched as a support for a lithographic printing plate, and developability is good. SiO ₂ / M ₂ O (molar ratio) is more preferably 1.0 to 2.0.

  The concentration of the alkali silicate in the developer is preferably 1 to 10% by mass, and 3 to 8% by mass with respect to the mass of the aqueous alkali solution, from the viewpoint of good developability and processing capability and convenience of waste liquid treatment. More preferably, 4 to 7% by mass is most preferable.

In a developer comprising a non-reducing sugar and a base, the non-reducing sugar means a saccharide that has no free aldehyde group or ketone group and therefore has no reducing property, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other. Glycosides in which saccharide reducing groups and non-saccharides are combined, and sugar alcohols reduced by hydrogenation of saccharides. Any of these can be suitably used in the present invention.
Examples of trehalose type oligosaccharides include saccharose and trehalose, and examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides.
Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-digit, D, L-talit, dulcit, allozulcit, meso-inosit and the like. . Furthermore, maltitol obtained by hydrogenation of a disaccharide, a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide, and the like can also be suitably exemplified.

Among the above, as the non-reducing sugar, sugar alcohol and saccharose are preferable, and among them, D-sorbite, mesoinosit, saccharose, and reduced starch syrup are more preferable because they have a buffering action in an appropriate pH range.
These non-reducing sugars may be used alone or in combination of two or more. The proportion of the non-reducing sugar in the developer is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass.

  In the alkali silicate or non-reducing sugar, an alkali agent as a base can be appropriately selected from conventionally known compounds and combined. Examples of the alkali agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, carbonic acid. Inorganic alkaline agents such as sodium, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium borate, potassium borate, ammonium borate, potassium citrate, tripotassium citrate, sodium citrate, etc. Is mentioned.

  Furthermore, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethylene An organic alkali agent such as imine, ethylenediamine, pyridine and the like can also be suitably exemplified. These alkaline agents may be used alone or in combination of two or more. Among them, sodium hydroxide and potassium hydroxide are preferable as the alkali agent. The reason is that the pH can be adjusted in a wide pH range by adjusting the amount added to the non-reducing sugar. Further, trisodium phosphate, tripotassium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they have a buffering action.

  The developer of the present invention is characterized by containing at least one selected from the group consisting of carboxyalkylthiosuccinic anhydride, carboxyalkylthiosuccinic acid, and salts thereof. Examples of at least one selected from the group consisting of carboxyalkylthiosuccinic anhydride, carboxyalkylthiosuccinic acid and salts thereof include compounds represented by the following general formula (i) or (ii). In the developer that can be used in the present invention, such compounds can be used singly or in combination of two or more.

In general formula (i), R ¹ represents an alkylene group having 1 to 30 carbon atoms, and M ¹ represents a hydrogen atom, a metal atom, or ammonium.

In General Formula (ii), R ² represents an alkylene group having 1 to 30 carbon atoms, and M ² , M ^3, and M ⁴ each independently represent a hydrogen atom, a metal atom, or ammonium.

In the carboxyalkylthiosuccinic anhydride or a salt thereof which is a compound represented by the general formula (i), in the carboxyalkylthiosuccinic acid or a salt thereof which is a compound represented by the general formula (ii), R ¹ and R ² are each carbon. It is an alkylene group having 1 to 30 atoms, and may be linear or branched. Specific examples of the alkylene group include ethylene group, propylene group, butylene group, pentylene group, hexylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene. Group, octadecylene group, nonadecylene group, eicosylene group, heicosylene group, docosylene group, tricosylene group, tetracosylene group, pentacosylene group, hexacosylene group, octacosylene group, nonacosylene group, triaconylene group and the like. Among these, an alkylene group having 1 to 18 carbon atoms is preferable.

In general formula (i) and general formula (ii), the metal atoms represented by M ¹ , M ² , M ^3, and M ⁴ are monovalent metal atoms, specifically lithium, sodium, potassium, etc. Examples thereof include monovalent metal atoms which are alkali metals, calcium, magnesium, zinc, aluminum, iron, cobalt, nickel, copper, tin and the like. Among these, lithium, sodium, potassium, calcium, and magnesium are preferable as the metal atom. Here, for a metal atom having a valence of 2 or more as a metal atom, a virtual metal atom obtained by dividing the metal atom by its valence is a metal atom corresponding to a monovalent, for example, a divalent metal such as calcium or magnesium. In some cases, it is expressed as Ca _1/2 , Mg _1/2 or the like, and in the case of a trivalent metal such as aluminum, it is expressed as Al _1/3 . Actually, in the compound represented by the general formula (i), in the case of a divalent metal atom, one of them has a structure of bridging two molecules, and in the case of a trivalent metal, one of them has three molecules. It becomes the structure which bridge | crosslinks. On the other hand, in the compound represented by the general formula (ii), one divalent metal atom corresponds to two of M ² , M ³ and M ⁴ . The divalent metal atom may correspond to two of M ² , M ³ and M ⁴ in one molecule of the compound represented by the general formula (ii), and is represented by the general formula (ii). that M ² of two molecules of the compound ^corresponds to two of of M ³ and M ^4, may be a structure bridging the two molecules. Further, the trivalent metal atom corresponds to 3 of 1 to 3 molecules of M ² , M ³ and M ⁴ of the compound represented by the general formula (ii).

In general formula (i) and general formula (ii), ammonium represented by M ¹ , M ² , M ³ and M ⁴ includes NH ₄ ⁺ , primary ammonium, secondary ammonium and tertiary ammonium. In primary ammonium, secondary ammonium and tertiary ammonium, the substituent may be an aliphatic group having 1 to 24 carbon atoms and an aromatic group, and the aliphatic group and aromatic group have a substituent. For example, it may be substituted with a hydroxyl group or the like. In the secondary ammonium and tertiary ammonium, each di- and tri-substituents may be the same or different, and may be bonded to each other to form a ring.
Examples of organic amines from which the above ammonium salts are derived include aliphatic amines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, ethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, Examples include alkanolamines such as triisopropanolamine, aromatic amines such as aniline, and heterocyclic amines such as morpholine, pyridine, pyrrolidine, and piperidine. Of these, morpholine and alkanolamine are particularly preferred.

  The compound represented by general formula (i) and general formula (ii) can be manufactured by a conventional method, for example, can be manufactured by the method disclosed by Unexamined-Japanese-Patent No. 8-337789. For example, by adding mercaptocarboxylic acid or a salt thereof to maleic anhydride, carboxyalkylthiosuccinic anhydride or carboxyalkylthiosuccinic anhydride which is a compound represented by the general formula (i) is obtained. In addition, the compound represented by the general formula (i) thus obtained is hydrolyzed and neutralized with an appropriate basic compound to form a salt as represented by the general formula (ii). Can be obtained.

  In the developer that can be used in the present invention, the content of at least one selected from the group consisting of carboxyalkylthiosuccinic anhydride, carboxyalkylthiosuccinic acid and salts thereof is suitably 0.001 to 10.0% by mass, Preferably it is 0.01-1.0 mass%, More preferably, it is 0.05-0.5 mass%.

As described above, a developer containing an alkali silicate or non-reducing sugar and a base is used as the alkaline developer, and Li ⁺ , Na ⁺ , K ⁺ , and NH ₄ ⁺ are conventionally used as the cation component. In a system containing a large amount of cations having a small ionic radius, it has high penetrability into the image recording layer and excellent developability, but dissolves up to the image area to cause image defects. Therefore, there is a certain limit to increasing the alkali concentration, and in order to completely process the image recording layer (residual film) in the non-image area without causing defects in the image area, it is delicate. It was required to set a proper liquid condition.
However, by using a cation having a large ionic radius as the cation component, the penetrability of the developer into the image recording layer can be suppressed, and the image density can be reduced without reducing the alkali concentration, that is, the developability. The dissolution inhibiting effect of the part can also be improved.
As the cation component, in addition to the alkali metal cation and ammonium ion, other cations can be used.

Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of developer can be obtained without replacing the developer in the developer tank for a long time. It is known that lithographic printing plate precursors can be processed. This replenishment method is also preferably applied in the present invention.
Various surfactants and organic solvents can be added to the developer and the replenisher as necessary for the purpose of promoting or suppressing developability, dispersing development residue, and improving the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants.
If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, and organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As the post-treatment of the printing plate obtained from the lithographic printing plate precursor according to the invention, these treatments can be used in various combinations.

In recent years, automatic developing machines for printing plate precursors have been widely used in the plate making and printing industries in order to streamline and standardize plate making operations. This automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for transporting the printing plate precursor, each processing liquid tank and a spray device. The exposed printing plate is pumped up while being transported horizontally. Each processing solution is sprayed from a spray nozzle and developed. In addition, recently, a method is also known in which a printing plate precursor is immersed and conveyed in a processing liquid tank filled with a processing liquid by a submerged guide roll or the like. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like.
In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if a lithographic printing plate having a higher printing durability is desired, a burning treatment is performed. Is given.
In the case of burning a lithographic printing plate, the preparation as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859 and JP-A-61-159655 is performed before burning. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method of applying the printing plate by dipping in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.
In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass).

The lithographic printing plate coated with the surface conditioning liquid is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor: BP-1300 sold by Fuji Photo Film Co., Ltd.). The heating temperature and time in this case are preferably in the range of 100 to 300 ° C. and in the range of 1 to 20 minutes, although depending on the type of components forming the image.
The burned lithographic printing plate can be appropriately subjected to known treatments such as washing and gumming as necessary, but when a surface-conditioning solution containing a water-soluble polymer compound or the like is used. Can omit so-called desensitizing treatment such as gumming.
The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

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

(Examples 1-7, Comparative Examples 1 and 2)
[Create support]
An aluminum plate having a thickness of 0.03 mm was grained on a surface using a nylon brush and a 400 mesh Pamiston water suspension, and then washed with water.
Etching was performed by immersing in 10% sodium hydroxide at 60 ° C. for 40 seconds, washed with running water, neutralized with 20% nitric acid, and washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% nitric acid aqueous solution with an anode electric quantity of 160 coulomb / dm ² using a sinusoidal alternating waveform current under the condition of V _A = 12.7V. The surface roughness measured was 0.6 μm (Ra indication). Subsequently, after being immersed in a 30% nitric acid aqueous solution and desmutted at 55 ° C. for 1 minute, the anode was adjusted to a thickness of 2.7 g / m ² in a 20% nitric acid aqueous solution at a current density of 2 A / dm ^2. Oxidized to prepare a substrate (I).

[Formation of hydrophilic layer]
A hydrophilic layer coating solution having the following composition was applied to the surface of the substrate (I) thus treated and dried at 80 ° C. for 30 seconds to prepare a substrate (II).
The coating amount after drying was 20 mg / m ² .

-Hydrophilic layer coating solution composition-
・ 2-Aminoethylphosphonic acid 0.06g
・ Ethylenediaminetetra (methylenephosphonic acid) 0.04g
・ Ion exchange water 40g
・ Methanol 60g

[Formation of image recording layer]
Next, the following image forming coating solution [P] was prepared, and this solution was applied to the substrate (II), which is an aluminum support on which the hydrophilic layer was formed, and dried at 100 ° C. for 1 minute. Negative-type planographic printing plate precursors 1 to 7 and Comparative Examples 1 and 2 were obtained. The coating amount after drying was 1.5 g / m ² .
-Coating solution for image formation [P]-
Acid generator (PF ₆ salt of 3-methoxy-4-diazodiphenylamine)
0.3g
Specific cross-linking agent or comparative cross-linking agent (compound described in Table 1) (Amount described in Table 1)
-Binder polymer [BP-1] (Amounts listed in Table 1)
・ Infrared absorber [IK-1] (the following structure) 0.2g
・ Victoria Pure Blue Dye 0.03g
・ Fluorine-based surfactant 0.01g
(Megafuck F-176, manufactured by DIC Corporation)
・ Methyl ethyl ketone 12g
・ Methanol 10g
・ 8g of 1-methoxy-2-propanol

Details of the compounds described in Table 1 below used in the image-forming coating solution [P] are as follows.
-Binder polymer [BP-1]-
Poly (p-hydroxystyrene), Maruka Linker MS-4P (trade name) manufactured by Maruzen Petrochemical Co., Ltd.
-Binder polymer [BP-2]-
It is a compound of the following structure.

-Binder polymer [Cresol novolac resin]-
m-cresol / p-cresol = 4/6 molar ratio of novolak resin. Weight average molecular weight: 5000
-Comparative crosslinking agent [phenol resol resin]-
Phenol resole resin, weight average molecular weight: 1200
-Comparative crosslinking agent [HM-1]-
The following structure is a compound.

-Infrared absorber [IK-1]-
It is a compound of the following structure.

The obtained negative lithographic printing plate precursors of Examples 1 to 7 and Comparative Examples 1 and 2 were imagewise exposed at an irradiation energy of 133 mJ / cm ² by an infrared exposure machine (Trendsetter 3244MT, manufactured by Creo). Next, the exposed lithographic printing plate precursor was subjected to a heat treatment (preheat treatment) at a predetermined temperature for 60 seconds using a warm air heating device (manufactured by Wisconsin Oven).
(Heating latitude evaluation)
It is performed several times while changing the heating temperature in the preheating treatment, and after the preheating treatment, it is developed with a developer manufactured by Fuji Photo Film Co., Ltd., DP-4 (1: 8 water dilution) to obtain a lithographic printing plate. It was. At this time, the minimum temperature of the preheating process in which the exposed portion formed an image and the minimum temperature at which a residual film was generated in the non-image portion were measured and are shown in Table 1 below. The presence or absence of image formation and residual film was confirmed visually. These temperature differences are the heating latitude, and the larger the temperature difference, the wider the heating latitude and the better the evaluation.

(Evaluation of printing durability)
In the plate making process, a lithographic printing plate was obtained at a preheat treatment temperature of 146 ° C.
The obtained lithographic printing plate was set in a Heidel KOR-D machine manufactured by Heidelberg, and printed on fine paper using GEOS-G (N) manufactured by Dainippon Ink as ink. Printing was performed while wiping the plate surface with a cleaner liquid (manufactured by Fuji Film Co., Ltd .: “Multi-cleaner”) every 5000 sheets printed. For each printing plate, the number of sheets with normal printed matter was counted and used as a measure of printing durability. The results are shown in Table 1.

As is clear from the results in Table 1, the negative lithographic printing plate precursor of the present invention containing a specific crosslinking agent in the image recording layer is superior in heating latitude during plate making in comparison with that using a comparative crosslinking agent. It can be seen that image formation is possible under a wide range of preheating temperature conditions, the printing durability of the image area is good, and the generation of the remaining film in the non-image area is effectively suppressed.
Further, Example 7 using a specific cross-linking agent having a highly hydrophobic functional group, or Example using a cross-linking agent or resole resin containing three or more benzene nuclei in the molecule and a specific cross-linking agent 2 and Example 4 show that the effect is excellent.

Claims (5)

On the support (A) a compound that decomposes by light or heat to generate an acid, (B) a crosslinking agent represented by the following general formula (I), (C) a binder polymer, and (D) an infrared absorber A negative lithographic printing plate precursor comprising an image recording layer containing

In the general formula (I), L ¹ is composed of one or more atoms selected from a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, and a sulfur atom, and is a linking group having a total number of atoms of 50 or less. Represents. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a nitro group, which further includes a hydroxyl group, a halogen group, an ether bond, and an amide. You may have a bond. n1 and n2 each represent an integer of 0 to 3, but n1 and n2 are not 0 at the same time.
R ³ and R ⁴ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. n3 and n4 each represent an integer of 0 to 3, but n3 and n4 are not 0 simultaneously.
m1 and m2 each represent an integer of 0 to 3, but m1 and m2 are not 0 at the same time. The negative lithographic printing plate precursor according to claim 1, wherein the crosslinking agent represented by the general formula (I) is a compound represented by the following general formula (I-2).

In the general formula (I-2), L ¹ is a carbon atom, a hydrogen atom, a nitrogen atom, is configured to include one or more atoms selected from oxygen atom and sulfur atom, the total atomic number less 50 Represents a linking group. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group, a halogen atom, or a nitro group, which further includes a hydroxyl group, a halogen group, an ether bond, and an amide You may have a bond. R ³ and R ⁴ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.   3. The negative lithographic printing according to claim 1, wherein the image recording layer further contains at least one crosslinking agent selected from a crosslinking agent containing three or more benzene nuclei in a molecule and a resole resin. Version original edition.   The negative according to any one of claims 1 to 3, wherein the content of the crosslinking agent represented by the general formula (I) is in the range of 5 to 90% by mass in the total solid content of the image recording layer. A lithographic printing plate precursor.   The negative lithographic printing plate precursor according to any one of claims 1 to 4, an exposure step of exposing the image positively, a preheating step of heating at 40 to 200 ° C after the exposure, and alkali development A plate making method of a lithographic printing plate precursor comprising a development step of removing an unexposed portion with a liquid.