JP4474296B2 - Planographic printing plate precursor - Google Patents

Abstract

The planographic printing plate precursor according to the invention is a planographic printing plate precursor, comprising a support and a recording layer formed on the support containing a sulfonium salt (A), an alkali-soluble resin (B), and an infrared absorbent (C), wherein the sulfonium salt (A) has a solubility of 25 mg/ml or more in aqueous 0.1 mol/L NaOH solution having a liquid temperature of 25°C at normal room temperature and atmospheric pressure. The invention provides a high-sensitivity planographic printing plate precursor that allows direct plate making by scanning exposure based on digital signals, for example and also suppresses generation of development scum.

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a positive lithographic printing plate precursor capable of so-called direct plate making that can be directly made by scanning infrared laser light based on a digital signal from a computer or the like.

  In recent years, the development of lasers has been remarkable. In particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared region to the infrared region have been increasing in output and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.

  The positive lithographic printing plate for infrared lasers that uses the infrared laser having a light emitting region in the infrared region as an exposure light source must have a binder resin that is soluble in an alkaline aqueous solution and an IR dye that absorbs light and generates heat. An image forming material as a component. The photosensitive composition disclosed in Patent Documents 1, 2, and 3 disclosed as a conventionally known technique, or the image forming material, when exposed to the infrared laser, the photosensitive composition in the non-exposed area (image area). The IR dye or the like acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by interaction with the binder resin. On the other hand, in the exposed portion (non-image portion), the IR dye or the like absorbs light and generates heat, so that the interaction between the IR dye or the like and the binder resin is weakened. Therefore, at the time of development, the exposed portion (non-image portion) is dissolved in the alkaline developer, and an image is formed. However, such a positive-type image forming material for infrared laser has a resistance between the solubility of the unexposed area (image area) in the developing solution and the solubility of the exposed area (non-image area) under various usage conditions. The difference is still not sufficient, and there is a problem that development stability (development latitude) depending on use conditions is low, and overdevelopment tends to occur at a high developer concentration. On the other hand, when a binder resin having low solubility in an alkaline developer is used for the purpose of suppressing this development, there is a problem that the developability (sensitivity) of the exposed area is lowered.

For this reason, for example, in the image forming material described in Patent Document 4, the development latitude is increased by including an onium salt. However, when a large amount of development processing is performed, a binder is contained in the developer of the automatic processor. Resin-derived insoluble residue (hereinafter referred to as development residue) tends to occur, and this improvement is desired.
WO97 / 39894 gazette JP 11-44956 A JP 11-218914 A JP 2002-278050 A

  The object of the present invention, which has been made in consideration of the drawbacks of the above-mentioned conventional techniques, is that direct plate-making by scanning exposure based on digital signals from a computer or the like is possible, and it is highly sensitive and suppresses development debris. It is to provide a lithographic printing plate precursor.

As a result of diligent research, the present inventors have found that the above object can be achieved by including a sulfonium salt that has an alkali-soluble group in the cation portion and has excellent solubility in an aqueous alkali solution. The present invention has been completed.
That is, the planographic printing plate precursor of the present invention has a recording layer containing an alkali-soluble resin, an infrared absorber, and a sulfonium salt on a support, and the sulfonium salt substitutes an alkali-soluble group in the cation part. A sulfonium salt having three phenyl groups as a group, and having a solubility in an aqueous NaOH solution of 0.1 mol / L and a liquid temperature of 25 ° C. under normal temperature and normal pressure, is 25 mg / ml or more. To do. In the present invention, “under normal temperature and normal pressure” means 25 ° C. and 1 atm.

Although the operation of the present invention is not clear, it is presumed as follows.
The sulfonium salt having the above-described solubility (hereinafter, appropriately referred to as “specific sulfonium salt”) has excellent solubility in an alkaline aqueous solution. Therefore, such a specific sulfonium salt has a function of dispersing the binder resin when it is eluted together with the binder into the developing solution of an automatic processor, and as a result, it suppresses generation of development residue due to aggregation of the binder resin. Presumed to be possible.
In the recording layer containing the specific sulfonium salt, an interaction between the specific sulfonium salt and the alkali-soluble resin due to the structure of the onium salt is formed in the unexposed area, and the development suppressing effect is enhanced. On the other hand, in the exposed area, when the interaction disappears due to the energy of exposure, the solubility of the specific sulfonium salt itself in a high alkaline aqueous solution is exhibited, the permeability of the developing solution is increased, and the recording layer is rapidly dissolved.
From these facts, it is presumed that the difference in solubility (discrimination) between the unexposed area and the exposed area in the alkaline aqueous solution (developer) widens, and as a result, high sensitivity can be achieved.

  According to the present invention, it is possible to provide a lithographic printing plate precursor capable of direct plate making by scanning exposure based on a digital signal from a computer or the like, having high sensitivity and capable of suppressing development debris generation.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor of the present invention is a sulfonium salt having three phenyl groups having an alkali-soluble group as a substituent on the cation part (A) on a support , and 0.1 mol at room temperature and normal pressure. / L and a recording layer containing a sulfonium salt (specific sulfonium salt) having a solubility in an aqueous NaOH solution at a liquid temperature of 25 ° C. of 25 mg / ml or more, (B) an alkali-soluble resin, and (C) an infrared absorber. It is characterized by having.

[Recording layer]
The recording layer according to the lithographic printing plate precursor according to the invention contains (A) a specific sulfonium salt, (B) an alkali-soluble resin, and (C) an infrared absorber as essential components. First, these constituent components will be described in detail.

[(A) Specific sulfonium salt]
The specific sulfonium salt in the present invention is a sulfonium salt having three phenyl groups having an alkali-soluble group as a substituent in the cation portion, and at a normal temperature and a normal pressure, 0.1 mol / L, and a liquid temperature of 25 The solubility in a NaOH aqueous solution at 0 ° C. is required to be 25 mg / ml or more. Moreover, in order to more efficiently suppress the development of development residue, the solubility is preferably 35 mg / ml or more, and more preferably 50 mg / ml or more.

Structure of a particular sulfonium salt of the present invention, the mosquito thione section and has three phenyl groups having an alkali-soluble group as a substituent. Examples of the alkali-soluble group include —COOH group, —OH group, —SO ₃ H group, —PO ₃ H ₂ group, etc. Among them, —COOH group or —OH group is preferable. These alkali-soluble group based on one of a phenyl group may also be one substituted, but it may also have a plurality of substituents.
Na us, the substitution position of the alkali-soluble group is not particularly limited.
On the other hand, examples of the anion moiety of the specific sulfonium salt include a strong acid residue. From the viewpoint of increasing the solubility in an alkaline aqueous solution, a strong acid residue having a plurality of acid groups or a strong acid residue derived from phosphonic acid is preferred.

Further, the specific sulfonium salt in the present invention has a structure having three phenyl groups having an alkali-soluble group as a substituent, an aqueous NaOH solution having a temperature of 0.1 mol / L and a liquid temperature of 25 ° C. under normal temperature and pressure. If the solubility with respect to is 25 mg / ml or more, the phenyl group may have a substituent other than the alkali-soluble group.
The substituent other than the alkali-soluble group is preferably a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. Is mentioned.

Examples of strong acid residues suitable as the anion moiety include residues derived from halogen ions (fluorine ions, chlorine ions, bromine ions, iodine ions), sulfonic acid compounds, carboxylic acid compounds, inorganic acid compounds, and the like. It is done. Such a compound preferably has a pKa <5. In particular, the strong acid residue preferably has a plurality of acid groups.
Further, in a strong acid residue, the residue of an inorganic acid compound, a halide anion, HS0 ₄ ^-, and halogen-containing complex anions, e.g., tetrafluoroborate, hexafluorophosphate, hexafluoro Ah cell sulfonates, and hexafluoroantimonate It is. Among these, Preferably, the strong acid residue derived from the inorganic acid compound containing a fluorine atom is mentioned. Specific examples of the inorganic acid compound containing a fluorine atom include, for example, tetrafluoroboric acid, tetrafluoroaluminic acid, tetrafluoroiron acid, tetrafluorogallic acid, hexafluorophosphoric acid, hexafluoroarsenic acid, hexafluoroantimonic acid, Hexafluorosilicic acid, hexafluoronickic acid, hexafluorotitanic acid, hexafluorozirconic acid and the like can be mentioned, and among them, hexanelurophosphoric acid, tetrafluoroboric acid, hexafluoroantimonic acid and the like are preferable.

Specific examples of the sulfonic acid compound from which the strong acid residue is derived include, for example, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, heptanesulfonic acid, and octanesulfonic acid. Nonane sulfonic acid, decane sulfonic acid, undecane sulfonic acid, dodecane sulfonic acid, tridecane sulfonic acid, tetradecane sulfonic acid, pentadecane sulfonic acid, hexadecane sulfonic acid, heptadecane sulfonic acid, octadecane sulfonic acid, nonadecane sulfonic acid, icosane Alkyl sulfonic acids such as sulfonic acid, heicosan sulfonic acid, docosan sulfonic acid, tricosane sulfonic acid, tetraconsan sulfonic acid;
For example, fluoromethanesulfonic acid, difluoromethanesulfonic acid, trifluoromethanesulfonic acid, chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid, tribromomethanesulfonic acid, iodomethanesulfone Acid, diiodomethanesulfonic acid, triiodomethanesulfonic acid, fluoroethanesulfonic acid, difluoroethanesulfonic acid, trifluoroethanesulfonic acid, pentafluoroethanesulfonic acid, chloroethanesulfonic acid, dichloroethanesulfonic acid, trichloroethanesulfonic acid, pentachloroethanesulfone Acid, tribromoethanesulfonic acid, pentabromoethanesulfonic acid, triiodoethanesulfonic acid, pentaiodoethanesulfonic acid, Fluoropropanesulfonic acid, trifluoropropanesulfonic acid, heptafluoropropanesulfonic acid, chloropropanesulfonic acid, trichloropropanesulfonic acid, heptachloropropanesulfonic acid, bromopropanesulfonic acid, tribromopropanesulfonic acid, heptabromopropanesulfonic acid, tri Iodopropanesulfonic acid, heptaiodopropanesulfonic acid, trifluorobutanesulfonic acid, nonafluorobutanesulfonic acid, trichlorobutanesulfonic acid, nonachlorobutanesulfonic acid, tribromobutanesulfonic acid, nonabromobutanesulfonic acid, triiodobutanesulfone Acid, nonaiodobutane sulfonic acid,

Trifluoropentanesulfonic acid, perfluoropentanesulfonic acid, trichloropentanesulfonic acid, perchloropentanesulfonic acid, tribromopentanesulfonic acid, perbromopentanesulfonic acid, triiodopentanesulfonic acid, periododopentanesulfonic acid, trifluorohexane Sulfonic acid, perfluorohexanesulfonic acid, trichlorohexanesulfonic acid, perchlorohexanesulfonic acid, perbromohexanesulfonic acid, periodohexanesulfonic acid, trifluoroheptanesulfonic acid, perfluoroheptanesulfonic acid, trichloroheptanesulfonic acid, perfluorohexane Chloroheptane sulfonic acid, perbromoheptane sulfonic acid, periodate heptane sulfonic acid, trifluorooctane sulfonic acid, perfluorooctance Phosphonic acid, trichlorooctane sulfonic acid, perchlorooctane sulfonic acid, perbromooctane sulfonic acid, periodooctane sulfonic acid, trifluorononane sulfonic acid, perfluorononane sulfonic acid, trichlorononane sulfonic acid, perchlorononane sulfonic acid, per Bromonotenesulfonic acid, periodononanesulfonic acid, trifluorodecanesulfonic acid, perfluorodecanesulfonic acid, trichlorodecanesulfonic acid, perchlorodecanesulfonic acid, perbromodecanesulfonic acid, periodododecanesulfonic acid, trifluoroundecane Sulfonic acid, perfluoroundecane sulfonic acid, trichloroundecane sulfonic acid, perchloroundecane sulfonic acid, perbromoundecane sulfonic acid, bayiodoundecane sulfone , Trifluorododecanesulfonic acid, perfluorododecanesulfonic acid, trichlorododecanesulfonic acid, perchlorododecanesulfonic acid, perbromododecanesulfonic acid, periodododecanesulfonic acid, trifluorotridecanesulfonic acid, perfluorotridecanesulfonic acid, trichloro Tridecanesulfonic acid, perchlorotridecanesulfonic acid, perbromotridecanesulfonic acid, periodotridecanesulfonic acid,

Trifluorotetradecane sulfonic acid, perfluorotetradecane sulfonic acid, trichlorotetradecane sulfonic acid, perchlorotetradecane sulfonic acid, perbromotetradecane sulfonic acid, periodate tetradecane sulfonic acid, trifluoropentadecane sulfonic acid, perfluoropentadecane sulfonic acid, trichloropentadecane sulfonic acid Acid, perchloropentadecanesulfonic acid, perbromopentadecanesulfonic acid, periodopentadecanesulfonic acid, perfluorohexadecanesulfonic acid, perchlorohexadecanesulfonic acid, perbromohexadecanesulfonic acid, periodohexadecanesulfonic acid, perfluoroheptadecanesulfonic acid Perchloroheptadecanesulfonic acid, perbromoheptadecanesulfonic acid, perio Heptadecanesulfonic acid, perfluorooctadecanesulfonic acid, berchlorooctadecanesulfonic acid, perpromooctadecanesulfonic acid, periodooctadecanesulfonic acid, perfluorononadecanesulfonic acid, perchlorononadecanesulfonic acid, perbromononadecanesulfonic acid, Periodononadecanesulfonic acid, perfluoroicosanesulfonic acid, perchloroicosanesulfonic acid, perbromoicosanesulfonic acid, periodoicosanesulfonic acid, perfluoroheneicosansulfonic acid, perchlorohicosansulfonic acid , Perbromohedicosan sulfonic acid, periodohenicosan sulfonic acid, perfluorodocosane sulfonic acid, perchlorodocosane sulfonic acid, perbromodocosane sulfonic acid, baiodo docosanth Phosphonic acid, perfluorotricosansulfonic acid, perchlorotricosansulfonic acid, perbromotricosansulfonic acid, periodotricosanesulfonic acid, perfluorotetraconsansulfonic acid, perchlorotetraconsansulfonic acid, perbromotetracene Haloalkyl sulfonic acids such as consan sulfonic acid and periodotetracon san sulfonic acid;

For example, cycloalkyl sulfonic acids such as cyclopentane sulfonic acid and cyclohexane sulfonic acid;
For example, 2-fluorocyclopentanesulfonic acid, 2-chlorocyclopentanesulfonic acid, 2-bromocyclopentanesulfonic acid, 2-iodocyclopentanesulfonic acid, 3-fluorocyclopentanesulfonic acid, 8-chlorocyclopentanesulfonic acid, 3-bromocyclopentanesulfonic acid, 3-iodocyclopentanesulfonic acid, 3,4-difluorocyclopentanesulfonic acid, 3,4-dichlorocyclopentanesulfonic acid, 3,4-dibromocyclopentanesulfonic acid, 3,4- Diiodocyclopentanesulfonic acid, 4-fluorocyclohexanesulfonic acid, 4-chlorocyclohexanesulfonic acid, 4-bromocyclohexanesulfonic acid, 4-iodocyclohexanesulfonic acid, 2,4-difluorocyclohexanesulfonic acid, 2,4 Dichlorocyclohexanesulfonic acid, 2,4-dibromocyclohexanesulfonic acid, 2,4-diiodocyclohexanesulfonic acid, 2,4,6-trifluorocyclohexanesulfonic acid, 2,4,6-trichlorocyclohexanesulfonic acid, 2,4 Halogenated cycloalkyl such as 1,6-tribromocyclohexanesulfonic acid, 2,4,6-triiodocyclohexanesulfonic acid, tetrafluorocyclohexanesulfonic acid, tetrachlorocyclohexanesulfonic acid, tetrabromocyclohexanesulfonic acid, tetraiodocyclohexanesulfonic acid Sulfonic acid;

For example, aromatic sulfonic acids such as benzene sulfonic acid, nanthalene sulfonic acid, anthracene sulfonic acid, phenanthrene sulfonic acid, pyrene sulfonic acid;
For example, 2-fluorobenzenesulfonic acid, 3-fluorobenzenesulfonic acid, 4-fluorobenzenesulfonic acid, 2-chlorobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-bromobenzenesulfonic acid, 3- Promobenzenesulfonic acid, 4-bromobenzenesulfonic acid, 2-iodobenzenesulfonic acid, 4-iodobenzenesulfonic acid, 2,4-difluorobenzenesulfonic acid, 2,6-difluorobenzenesulfonic acid, 2,4-dichlorobenzene Sulfonic acid, 2,6-dichlorobenzenesulfonic acid, 2,4-dibromobenzenesulfonic acid, 2,6-dibromobenzenesulfonic acid, 2,4-diiodobenzenesulfonic acid, 2,6-diiodobenzenesulfonic acid, 2,4,6-trifluorobenze Sulfonic acid, 3,4,5-trifluorobenzenesulfonic acid, 2,4,6-trichlorobenzenesulfonic acid, 3,4,5-trichlorobenzenesulfonic acid, 2,4,6-tribromobenzenesulfonic acid, 3 , 4,5-tribromobenzenesulfonic acid, 2,4,6-triiodobenzenesulfonic acid, 3,4,5-triiodobenzenesulfonic acid, pentafluorobenzenesulfonic acid, pentachlorobenzenesulfonic acid, pentabromobenzenesulfone Acid, pentaiodobenzenesulfonic acid, fluoronaphthalenesulfonic acid, chloronaphthalenesulfonic acid, bromonaphthalenesulfonic acid, iodonaphthalenesulfonic acid, fluoroanthracenesulfonic acid, chloroanthracenesulfonic acid, bromoanthracenesulfonic acid, iodoanthone sense Halogenated aromatic contact sulfonic acids such as acid;

For example, p-toluenesulfonic acid, 4-isopropylbenzenesulfonic acid, 3,5-bis (trimethyl) benzenesulfonic acid, 3,5-bis (isopropyl) benzenesulfonic acid, 2,4,6-tris (trimethyl) benzene Alkyl aromatic sulfonic acids such as sulfonic acid and 2,4,6-tris (isopropyl) benzenesulfonic acid;
For example, 2-trifluoromethylbenzenesulfonic acid, 2-trichloromethylbenzenesulfonic acid, 2-tribromomethylbenzenesulfonic acid, 2-triiodomethylbenzenesulfonic acid, 3-trifluoromethylbenzenesulfonic acid, 3-trichloromethyl Benzenesulfonic acid, 3-tribromomethylbenzenesulfonic acid, 3-triiodomethylbenzenesulfonic acid, 4-trifluoromethylbenzenesulfonic acid, 4-trichloromethylbenzenesulfonic acid, 4-tribromomethylbenzenesulfonic acid, 4- Triiodomethylbenzenesulfonic acid, 2,6-bis (trifluoromethyl) benzenesulfonic acid, 2,6-bis (trichloromethyl) benzenesulfonic acid, 2,6-bis (tribromomethyl) benzenesulfonic acid, 2, 6-bis ( Lyodomethyl) benzenesulfonic acid, 3,5-bis (trifluoromethyl) benzenesulfonic acid, 3,5-bis (trichloromethyl) benzenesulfonic acid, 3,5-bis (tribromomethyl) benzenesulfonic acid, 3,5 A halogenated alkyl aromatic sulfonic acid such as bis (triiodomethyl) benzenesulfonic acid;
For example, aromatic aliphatic sulfones such as benzyl sulfonic acid, phenethyl sulfonic acid, phenyl propyl sulfonic acid, phenyl butyl sulfonic acid, phenyl pentyl sulfonic acid, phenyl hexyl sulfonic acid, phenyl heptyl sulfonic acid, phenyl octyl sulfonic acid, and phenyl nonyl sulfonic acid acid;

For example, 4-fluorophenylmethylsulfonic acid, 4-chlorophenylmethylsulfonic acid, 4-bromophenylmethylsulfonic acid, 4-iodophenylmethylsulfonic acid, tetrafluorophenylmethylsulfonic acid, titrachlorophenylmethylsulfonic acid, tetrabromophenylmethyl Sulfonic acid, tetraiodophenylmethylsulfonic acid, 4-fluorophenylethylsulfonic acid, 4-chlorophenylethylsulfonic acid, 4-bromophenylethylsulfonic acid, 4-iodophenylethylsulfonic acid. 4-fluorophenylpropylsulfonic acid, 4-chlorophenylpropylsulfonic acid, 4-bromophenylpropylsulfonic acid, 4-iodophenylpropylsulfonic acid, 4-fluorophenylbutylsulfonic acid, 4-chlorophenylbutylsulfonic acid, 4-bromophenyl Halogenated araliphatic sulfonic acids such as butylsulfonic acid and 4-iodophenylbutylsulfonic acid;
Examples thereof include alicyclic sulfonic acids such as camphor sulfonic acid and adamantane carboxylic acid.
Of these, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid are particularly preferable from the viewpoints of availability and production suitability.

Specific examples of the carboxylic acid compound from which the strong acid residue is derived include, for example, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hexanoic acid, heptanoic acid, octanoic acid, Nonsaturation such as nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, icosanoic acid, heicosanoic acid, docosanoic acid, tricosanoic acid carboxylic acid;
For example, fluoroacetic acid, chloroacetic acid, bromoacetic acid, iodoacetic acid, difluoroacetic acid, dichloroacetic acid, dibromoacetic acid, diiodoacetic acid, trifluoroacetic acid, trichloroacetic acid, tribromoacetic acid, triiodoacetic acid, 2-fluoropropionic acid, 2-chloropropion Acid, 2-bromopropionic acid, 2-iodopropionic acid, trifluoropropionic acid, trichloropropionic acid, pentafluoropropionic acid, pentachloropropionic acid, pentabromopropionic acid, pentaiodopropionic acid, 2,2-bis (Trifluoromethyl) propionic acid, 2,2-bis (trichloromethyl) propionic acid, 2,2-bis (tribromomethyl) propionic acid, 2,2-bis (triiodomethyl) propionic acid, trifluorobutyric acid, Trichlorobutyric acid, pentaful Robutyric acid, heptachlorobutyric acid, heptafluorobutyric acid, heptabromobutyric acid, heptaiobutyric acid, heptafluoroisobutyric acid, heptachloroisobutyric acid, heptabromoisobutyric acid, heptaiodoisobutyric acid, trifluorovaleric acid, 5H-perfluorovaleric acid, 5H-perchloro Valeric acid, 5H-perpromovaleric acid, 5H-periodovaleric acid, nonafluorovaleric acid, nonachlorovaleric acid, nonabromovaleric acid, nonaiodovaleric acid, trifluorohexanoic acid, trichlorohexanoic acid, perfluorohexanoic acid, perchlorohexanoic acid, Perbromohexanoic acid, periodiohexanoic acid, 7-chlorododecafluoroheptanoic acid, 7-chlorododecachloroheptanoic acid, 7-chlorododecabromoheptanoic acid, 7-chlorododecaiodoheptanoic acid, trifluoroheptanoic acid, Chloro heptanoic acid, 7H-perfluoroheptanoic acid, 7H-perchlorethylene heptanoic acid, 7H-Per-bromo heptanoic acid, 7H-per-iodo-heptanoic acid,

Trifluorooctanoic acid, trichlorooctanoic acid, pentadecafluorooctanoic acid, pentadecachlorooctanoic acid, pentadecabromooctanoic acid, pentadeoxyiodooctanoic acid, trifluorononanoic acid, trichlorononanoic acid, 9H-hexadecafluorononanoic acid, 9H-hexadecachlorononanoic acid, 9H-hexadecabromononanoic acid, 9H-hexadecaiodononanoic acid, perfluorononanoic acid, perchlorononanoic acid, perbromononanoic acid, periodononanoic acid, trifluorodecanoic acid, trichlorodecanoic acid , Nonadecafluorodecanoic acid, nonadecachlorodecanoic acid, nonadecabromodecanoic acid, nonadecanoiododecanoic acid, trifluoroundecanoic acid, trichloroundecanoic acid, perfluoroundecanoic acid, perchloroundecanoic acid, perbromo Decanoic acid, periodododecanoic acid, trifluorododecanoic acid, trichlorododecanoic acid, perfluorododecanoic acid, perchlorododecanoic acid, perbromododecanoic acid, periodododecanoic acid, trifluorotridecanoic acid, trichlorotridecanoic acid, perfluorotridecanoic acid Decanoic acid, perchlorotridecanoic acid, perbromotridecanoic acid, periodotridecanoic acid, trifluorotetradecanoic acid, trichlorotetradecanoic acid, perfluorotetradecanoic acid, perchlorotetradecanoic acid, perbromotetradecanoic acid, periodotetradecanoic acid, Trifluoropentadecanoic acid, trichloropentadecanoic acid, perfluoropentadecanoic acid, perchloropentadecanoic acid, perbromopentadecanoic acid, periodopentadecanoic acid, perfluorohexadecanoic acid Perchlorohexadecanoic acid, perbromohexadecanoic acid, periodohexadecanoic acid, perfluorohebutadecanoic acid, perchloroheptadecanoic acid, perbromoheptadecanoic acid, periodoheptadecanoic acid, perfluorooctadecanoic acid, perchlorooctadecanoic acid, Perbromooctadecanoic acid, periodooctadecanoic acid, perfluorononadecanoic acid, perchlorononadecanoic acid, perbromononadecanoic acid, periodononadecanoic acid, perfluoroicosanoic acid, perchloroicosanoic acid, perbromoicosano Acid, valiodoicosanoic acid, perfluorohenicosanoic acid, perchlorohenicosanoic acid, perbromohenicosanoic acid, periodohenicosanoic acid, perfluorodocosanoic acid, perchlorodocosanoic acid, perbromo Docosanoic acid, periodate doco Halogenated saturated fatty acid carboxylic acids such as sanic acid, perfluorotricosanoic acid, perchlorotricosanoic acid, perbromotricosanoic acid, and periodotricosanoic acid;

For example, hydroxy aliphatic carboxylic acids such as glycolic acid, lactic acid, glyceric acid, 3-hydroxy-2-methylpropionic acid;
For example, 3-hydroxy-2- (trifluoromethyl) propionic acid, 3-hydroxy-2- (trichloromethyl) propionic acid, 3-hydroxy-2- (tribromomethyl) propionic acid, 3-hydroxy-2- ( Triiodomethyl) propionic acid, 2-hydroxy-2- (trifluoromethyl) butyric acid, 2-hydroxy-2- (trichloromethyl) butyric acid, 2-hydroxy-2- (tribromomethyl) butyric acid, 2-hydroxy-2 -Halogenation such as (triiodomethyl) butyric acid and droquine aliphatic carboxylic acid;
For example, cycloaliphatic carboxylic acids such as cyclohexanecarboxylic acid, camphoric acid, adamantanoic acid;
For example, 4-fluorocyclohexanecarboxylic acid, 4-chlorocyclohexanecarboxylic acid, 4-bromocyclohexanecarboxylic acid, 4-iodocyclohexanecarboxylic acid, pentafluorocyclohexanecarboxylic acid, pentachlorocyclohexanecarboxylic acid, pentabromocyclohexanecarboxylic acid, pentaiodo Halogenation of cyclohexanecarboxylic acid, 4- (trifluoromethyl) cyclohexanecarboxylic acid, 4- (trichloromethyl) cyclohexanecarboxylic acid, 4- (tribromomethyl) cyclohexanecarboxylic acid, 4- (triiodomethyl) cyclohexanecarboxylic acid, etc. Alicyclic carboxylic acids;

For example, aromatic carboxylic acids such as benzoic acid, naphthoic acid, anthracene carboxylic acid, pyrene carboxylic acid, pyrylene carboxylic acid, pentaphen carboxylic acid;
For example, fluorobenzoic acid, chlorobenzoic acid, bromobenzoic acid, iodobenzoic acid, difluorobenzoic acid, dichlorobenzoic acid, dibromobenzoic acid, diiodobenzoic acid, trifluorobenzoic acid, trichlorobenzoic acid, tribromobenzoic acid, triiodobenzoic acid , Tetrafluorobenzoic acid, tetrachlorobenzoic acid, tetrabromobenzoic acid, tetraiodobenzoic acid, pentafluorobenzoic acid, pentachlorobenzoic acid, pentabromobenzoic acid, pentaiodobenzoic acid, fluoronaphthoic acid, chloronaphthoic acid, bromonaphthoic acid, iodonaphthoic acid Perfluoronaphthoic acid, perchloronaphthoic acid, perbromonaphthoic acid, periodonaphthoic acid, fluoroanthracene carboxylic acid, chloroanthracene carboxylic acid, bromoanthanthene carboxylic acid, Over de-anthracene carboxylic acid, perfluoro-anthracene carboxylic acid, perchlorethylene anthracene carboxylic acid, perfluoro-bromo-anthracene carboxylic acid, halogenated aromatic carboxylic acids such as per-iodo-anthracene carboxylic acid, benzoyl formic acid;

For example, alkyl aromatic carboxylic acids such as toluic acid and 2,4,6-tri (isopropyl) benzoic acid;
For example, 2-trifluoromethylbenzoic acid, 2-trichloromethylbenzoic acid, 2-tribromomethylbenzoic acid, 2-triiodomethylbenzoic acid, 3-trifluoromethylbenzoic acid, 3-trichloromethylbenzoic acid, 3- Tribromomethylbenzoic acid, 3-triiodomethylbenzoic acid, 4-trifluoromethylbenzoic acid, 4-trichloromethylbenzoic acid, 4-tribromomethylbenzoic acid, 4-triiodomethylbenzoic acid, 2-fluoro-4 -(Trifluoromethyl) benzoic acid, 2-chloro-4- (trichloromethyl) benzoic acid, 2-bromo-4- (tribromomethyl) benzoic acid, 2,3,4-trifluoro-6- (trifluoro Methyl) benzoic acid, 2,3,4-trichloro-6- (trichloromethyl) benzoic acid, 2,3,4-tribromo-6- ( (Ribromomethyl) benzoic acid, 2,3,4-triiodo-6- (triiodomethyl) benzoic acid, 2-iodo-4- (triiodomethyl) benzoic acid, 2,4-bis (trifluoromethyl) benzoic acid, 2,4-bis (trichloromethyl) benzoic acid, 2,4-bis (tribromomethyl) benzoic acid, 2,4-bis (triiodomethyl) benzoic acid, 2,6-bis (trifluoromethyl) benzoic acid 2,6-bis (trichloromethyl) benzoic acid, 2,6-bis (tribromomethyl) benzoic acid, 2,6-bis (triiodomethyl) benzoic acid, 3,5-bis (trifluoromethyl) benzoic acid Acid, 3,5-bis (trichloromethyl) benzoic acid, 3,5-bis (tribromomethyl) benzoic acid, 3,5-bis (triiodomethyl) benzoic acid, 2,4,6-tris (tri Fluoromethyl) benzoic acid, 2,4,6-tris (trichloromethyl) benzoic acid, 2,4,6-tris (tribromomethyl) benzoic acid, 2,4,6-tris (triiodomethyl) benzoic acid, 2, -Chloro-6-fluoro-3-methylbenzoic acid, trifluoromethylnaphthoic acid, trichloromethylnaphthoic acid, tribromomethylnaphthoic acid, triiodomethylnaphthoic acid,

Bis (trifluoromethyl) naphthoic acid, bis (trichloromethyl) naphthoic acid, bis (tribromomethyl) naphthoic acid, bis (triiodomethyl) naphthoic acid, tris (trifluoromethyl) naphthoic acid, tris (trichloromethyl) naphthoic acid Haloalkyl aromatics such as acids, tris (tribromomethyl) naphthoic acid, tris (triiodomethyl) naphthoic acid, trifluoromethylanthracene carboxylic acid, trichloromethylanthracene carboxylic acid, tribromomethylanthracene carboxylic acid, triiodomethylanthracene carboxylic acid Group carboxylic acids;
For example, an alkoxy aromatic carboxylic acid such as anisic acid, betramic acid, o-bertramic acid;
For example, 4-trifluoromethoxybenzoic acid, 4-trichloromethoxybenzoic acid, 4-tribromomethoxybenzoic acid, 4-triiodomethoxybenzoic acid, 4-pentafluoroethoxybenzoic acid, 4-pentachloroethoquinbenzoic acid, 4-pentabromoethoxybenzoic acid, 4-pentaiodoethoxybenzoic acid, 3,4-bis (trifluoromethoxy) benzoic acid, 3,4-bis (trichloromethoxy) benzoic acid, 3,4-bis (tribromomethoxy) ) Benzoic acid, 3,4-bis (triiodomethoxy) benzoic acid, 2,5-bis (2,2,2-trifluoroethoxy) benzoic acid, 2,5-bis (2,2,2-trichloroethoxy) ) Benzoic acid, 2,5-bis (2,2,2-tribromoethoxy) benzoic acid, 2,5-bis (2,2,2-triiodoethoxy) ) Haloalkoxy aromatic carboxylic acids such as benzoic acid;
For example, hydroxy aromatic carboxylic acids such as salicylic acid, o-pyrocatechuic acid, α-resorcylic acid, gentesic acid, α-resorcylic acid, protocatechuic acid, α-resorcylic acid, gallic acid and the like;
For example, hydroxyalkoxy aromatic carboxylic acids such as vanillic acid and isovanillic acid;
For example, nitroaromatic carboxylic acids such as trinitrobenzoic acid;
For example, an amino aromatic carboxylic acid such as anthranilic acid;
For example, α-toluic acid, hydrocinnamic acid, hydroatropic acid, 3-phenylpropionic acid, 4-phenylbutyric acid, 5-phenylpentanoic acid, 6-phenylhexanoic acid, 7-phenylheptanoic acid, 6- (2-naphthyl) Araliphatic carboxylic acids such as hexanoic acid;
For example, hydroxyaromatic carboxylic acids such as homogentisic acid;
For example, aromatic hydroxyalkyl carboxylic acids such as mandelic acid, benzylic acid, atrolactic acid, tropic acid, atroglyceric acid;
For example, 2-formylacetic acid, acetoacetic acid, 3-benzoylpropionic acid, 4-formylbutyric acid, 3-oxovaleric acid, 5-oxovaleric acid, 3,5-dioxovaleric acid, 6-formylhexanecarboxylic acid, 2 -Oxo-1-cyclohexanecarboxylic acid, 4- (2-oxobutyl) benzoic acid, p- (3-formylpropyl) benzoic acid, 4-formylphenylacetic acid, β-oxocyclohexanepropionic acid, pyruvic acid, and other oxocarboxylic acids Is mentioned.
Among these, benzoyl formic acid, acetic acid, and benzoic acid are particularly preferable.

Specific examples of the specific sulfonium salt as described above [(S-7), (S-8), (S-16), (S-17), (S-25), (S-26), (S- 34), (S-35), (S-43), (S-44), (S-52), (S-53), (S-61), (S-62), and (S- 64) to (S-67) ] are shown below, but the present invention is not limited thereto.
Incidentally, Oite the embodiment, 25 ° C., under 1 atm, at 0.1 mol / L, and was also shown solubility NaOH aqueous liquid temperature 25 ° C..

(Synthesis of specific sulfonium salt in the present invention)
Such a specific sulfonium salt can be generally synthesized by a Friedel-Craft reaction or a Grineer reaction between a sulfide compound and an aromatic compound. Examples of the synthesis method are described in J. Amer. Chem. Soc. 112 (16), 1990; pp 6004-6015, J. MoI. Org. Chem. 1998; pp 5571-5573, WO 02/081439 A1 pamphlet, or European Patent (EP) No. 1113005.

In the recording layer of the present invention, the content of the specific sulfonium salt is preferably 1 to 30% by mass, and 3 to 25% by mass in the total solid content of the recording layer from the viewpoint of sensitivity and development residue generation. % Is more preferable, and 5 to 20% by mass is particularly preferable.
In addition, the specific sulfonium salt may be used individually by 1 type, and may use 2 or more types together.

In the recording layer of the present invention, a general onium salt other than the specific sulfonium salt can be used in combination as a dissolution inhibitor. Such general onium salts will be described in the following other components.
When the above-mentioned specific sulfonium salt and a general onium salt are used in combination, the general onium salt can be used in the range of 0 to 30% by mass with respect to the specific sulfonium salt, preferably 0.5 to It is in the range of 15% by mass.

[(B) Alkali-soluble resin]
The alkali-soluble resin in the present invention includes a homopolymer containing an acidic group in the main chain and / or side chain in the resin, a copolymer thereof, or a mixture thereof.
Among these, those having an acidic group listed in the following (1) to (6) in the main chain and / or side chain of the polymer are preferable from the viewpoint of solubility in an alkaline developer and expression of dissolution inhibiting ability.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Force rubonic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

  In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrogen atom or a hydrocarbon group which may have a substituent. .

  Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), (1) an alkali-soluble resin having a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable. An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolac resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (m-, p- or m- / p-mixed) and formaldehyde, and pyrogallol and acetone. Can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned.

  Here, examples of the compound having a phenol group in the side chain include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

  (2) As an alkali-soluble resin having a sulfonamide group, for example, a polymer composed of a minimum constituent unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. For example, the following general formula (i) to general formula ( and a compound represented by v).

[Wherein, X ¹ and X ² each independently represent —O— or NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , and R ¹⁶ each independently represent an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group, or an aralkylene group. . R ³ , R ⁷ , and R ¹³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group. R ⁶ and R ¹⁷ each independently represents a C 1-12 alkyl group, cycloalkyl group, aryl group or aralkyl group which may have a substituent. R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each independently represents a single bond or a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a substituent. Y ¹ and Y ² each independently represents a single bond or CO. ]

  Among the compounds represented by the general formula (i) to the general formula (v), in the lithographic printing plate precursor according to the invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N -(P-aminosulfonylphenyl) acrylamide etc. can be used conveniently.

  (3) As an alkali-soluble resin having an active imide group, for example, a polymer composed of a minimum constituent unit derived from a compound having an active imide group as a main constituent can be mentioned. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

  Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) As an alkali-soluble resin having a strong rubonic acid group, for example, a minimum constituent unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule is a main constituent. Can be mentioned.
(5) As the alkali-soluble polymer having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and a polymerizable unsaturated group in the molecule is a main structural unit. Can be mentioned.
(6) As an alkali-soluble resin having a phosphate group, for example, a minimum structural unit derived from a compound having at least one phosphate group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

  (A) The minimum structural unit having an acidic group selected from the above (1) to (6) that constitutes the alkali-soluble resin is not necessarily limited to one kind, and the minimum structural unit having the same acidic group Two or more kinds or those obtained by copolymerizing two or more kinds of minimum structural units having different acidic groups can also be used.

  The copolymer preferably contains 10 mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized, and is contained in an amount of 20 mol% or more. Those are more preferred. If it is less than 10 mol%, the development latitude tends to be insufficiently improved.

In this invention, when alkali-soluble resin is a copolymer, the other compound which does not contain the acidic group of said (1)-(6) can also be used as a compound which comprises a copolymer. Examples of other compounds not containing an acidic group of (1) to (6) include the compounds listed in the following (m1) to (m12), but are not limited thereto.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, etc. .
(M3) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, glycidyl methacrylate, etc. Alkyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N- Acrylamide or methacrylamide such as ethyl-N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  In the present invention, the alkali-soluble resin is preferably a polymerizable monomer having a phenolic hydroxyl group or a homopolymer or copolymer of a polymerizable monomer having an active imide group, and particularly m-aminosulfonylphenyl methacrylate, N A homopolymer or copolymer of a polymerizable monomer having a sulfonamide group such as-(p-aminosulfonylphenyl) methacrylamide or N- (p-aminosulfonylphenyl) acrylamide is preferred.

  The alkali-soluble resin in the present invention preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. . In particular, in the present invention, when the alkali-soluble resin is a resin such as phenol formaldehyde resin or cresol aldehyde resin, those having a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 are preferable. .

One kind of these alkali-soluble resins may be used, or two or more kinds may be used in combination.
In the recording layer of the present invention, the content of the alkali-soluble resin is preferably in the range of 30 to 98% by mass in the total solid content of the recording layer, from the viewpoint of sensitivity, image formability, and film durability, and is preferably 40 to 95%. The range of mass% is more preferable, and the range of 50 to 90 mass% is particularly preferable.

[(C) Infrared absorber]
The infrared absorber contained in the recording layer in the present invention has a light absorption region in an infrared region of 700 nm or more, preferably 750 to 1200 nm, and exhibits a light / heat conversion ability by light in this wavelength region. Point to. Specifically, various dyes or pigments that absorb light in the above wavelength range and generate heat can be used.

  As the dye, commercially available dyes, for example, known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, 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, Examples thereof include oxonol dyes, diimonium dyes, aminium dyes, and croconium dyes.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924 Trimethine thiapyrylium salts described in JP-A Nos. 57-142645 (US Pat. No. 4,327,169), JP-A Nos. 58-181051, 58-220143, 59-41363, 59- 84248, 59-84249, 59-146063, 59-146061, pyrylium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 And the pyrylium compounds disclosed in JP-B-5-13514 and JP-A-5-19702 are also preferably used. .

  Another example of a preferable dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the dyes represented by the following general formulas (a) to (e) are preferable because of their excellent photothermal conversion efficiency. Particularly, the cyanine dyes represented by the following general formula (a) were used in the recording layer according to the present invention. In this case, it is most preferable because it gives a high interaction with the alkali-soluble resin and is excellent in stability and economy.

In formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh ^_2, -X ₂ -L ¹ or a group shown below. Here, 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 carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

In the above formula, Xa ^- has Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the 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 formula (a) has an anionic substituent in the structure and neutralization of charge 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.

  Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A-2001-133969. And those described in paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents are bonded to each other to form a ring structure. Also good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Na ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group Or a substituent selected from amino groups, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in the general formula (b), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. From the viewpoint of the effect.

  Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.

In the general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are each a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thiol group, Represents a group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a) ^- it is synonymous.

  In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

In the general formula (d), R ²⁹ to R ³¹ each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ taken together, may form a ring, further, when R ³³ or R ³⁴ there are a plurality, R ³³ or between R ³⁴ each other may be bonded to each other to form a ring. X ² and X ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group, and at least one of X ² and X ³ represents a hydrogen atom or an alkyl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ⁻ represents a counter anion and has the same meaning as Za ⁻ in the general formula (a).

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

In the general formula (e), R ^{35 to} R ⁵⁰ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, a carbonyl group, a thio group, or a sulfonyl group. , A sulfinyl group, an oxy group, an amino group, and an onium salt structure, and may further have a substituent depending on the structure. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein are IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

  In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

  Examples of pigments include commercially available pigments or color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), and “ The pigments described in “Printing Ink Technology”, published by 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 polymer-bonded pigments. 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, isotopic pigments Indolinone pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, and carbon black can be used.

  These pigments may be used without surface treatment or may be used after surface treatment. As the surface treatment method, a method of surface coating of resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate) to the pigment surface Etc. 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 pigment particle size is preferably in the range of 0.01 μm to 10 μm, and from the viewpoint of the stability of the pigment dispersion in the coating solution and the uniformity of the recording layer, it is preferably in the range of 0.05 μm to 1 μm. More preferably, it is particularly preferably in the range of 0.1 to 1 μm.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Dispersers include ultrasonic dispersers, sand mills, attritors, par mills, super mills, ball mills, impellers, desperzers, KD mills, colloid mills, Dynatrons, three-rollers Lumil, pressure kneader and the like. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  These pigments or dyes are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the recording layer, from the viewpoints of sensitivity, recording layer uniformity and durability. . In particular, in the case of a dye, it is preferably contained in a proportion of 0.5 to 10% by mass, and in the case of a pigment, it is preferably contained in a proportion of 0.1 to 10% by mass.

[Other ingredients]
Various additives can be added to the recording layer in the invention as needed.
For example, when an onium salt other than a specific sulfonium salt, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, a polyfunctional amine compound, or the like is added to adjust the solubility of the recording layer, (B) a developer of an alkali-soluble resin It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibiting function in the aqueous solution, and among them, onium salts, o-quinonediazide compounds, sulfonic acid alkyl esters, etc. are thermally decomposable, and in the state where they are not decomposed, the alkali-soluble resin is dissolved. It is preferable to use a substance that substantially reduces the property in terms of improving the dissolution inhibition of the image portion in the developer.

Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230;
Ammonium salts described in US Pat. Nos. 4,069,055, 4,069,056 and JP-A-3-140140;
D. 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;
J. et al. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts;

  J. et al. 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 Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 Sulfonium salts described in 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);
C. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) in [Chemical Formula 5] [Chemical Formula 6] described in Unexamined-Japanese-Patent No. 2002-229186 is preferable.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, JP-B-41-11222, JP-B-45-9610, JP-B-49-174781, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267 No. 1,005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

  The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, particularly preferably the total solid content of the recording layer. Preferably it is the range of 1-2 mass%. These compounds can be used alone, but may be used as a mixture of several kinds.

  The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.

In addition, cyclic acid anhydrides, phenols, and organic acids can be added to the recording layer in the present invention for the purpose of improving sensitivity.
Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.
The proportion of the cyclic acid anhydride, phenols, and organic acids in the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by mass.

  In addition to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and JP-A-5 A crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 can be appropriately added depending on the purpose.

In the recording layer of the present invention, a nonionic surfactant as described in JP-A-62-251740 and JP-A-3-208514 is disclosed in order to broaden the stability of processing with respect to development conditions. An amphoteric surfactant as described in JP-A-59-121044 and JP-A-4-13149, a siloxane-based compound as described in EP950517, and JP-A-11-288093 Such fluorine-containing monomer copolymers 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 the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the recording layer is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

Further, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image coloring agent can be added to the recording layer in the present invention.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. 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) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the recording layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the recording layer.

  Furthermore, a plasticizer is added to the recording layer in the present invention as needed in order to impart flexibility of the coating film. Examples of the plasticizer include butyl phthalyl, 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 oligomers and polymers are used.

[Layer structure of recording layer]
The recording layer of the lithographic printing plate precursor according to the invention may be any of a single layer type, a phase separation type, and a multilayer type.
As the single-layer recording layer, for example, the configuration of the photosensitive layer described in JP-A-7-285275 and WO97 / 39894 can be similarly applied. As the phase separation type recording layer, for example, the configuration of the photosensitive layer described in JP-A No. 11-44956 can be similarly applied. Examples of the multilayer recording layer include, for example, JP-A-11-218914, US Pat. No. 6,352,812 B1, US Pat. No. 6,352,811 B1, US Pat. No. 6,358,669 B1, US Pat. No. 6,534,238 B1, and EP 864420 B1. The structure of the photosensitive layer described can be applied similarly. However, the configuration of the recording layer in the present invention is not limited to these.
In the case where the recording layer is configured as a multilayer recording layer, it is preferable that the specific sulfonium salt in the present invention is contained in the uppermost layer from the viewpoint of the effect.

[Method for forming recording layer]
The recording layer in the present invention can be formed by preparing a recording layer coating solution by dissolving the components constituting the recording layer in a solvent, coating on a suitable support, and drying. In addition, an undercoat layer, which will be described later, and a backcoat layer, which are provided according to the purpose, can be formed in the same manner.
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, but are not limited to, ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. Is not to be done. 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.
In addition, the coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally, the coating amount after drying is preferably 0.5 to 5.0 g / m ² . 6 to 2.0 g / m ² is more preferable.
The coating amount in the case of a multilayer recording layer comprising two recording layers is preferably 0.1 to 5.0 g / m ² , more preferably 0.2 to 3.0 g / m ² as the lower layer. As the upper layer (uppermost layer), preferably the amount to be 0.01~5.0g / m ^2, more preferably the amount to be 0.05 to 2.0 g / m ^2.

  Various methods can be used for applying the recording layer coating solution. 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 properties of the photosensitive film deteriorate.

  In the recording layer coating solution of the present invention, a surfactant for improving coating properties, for example, a fluorine-based surfactant as described in JP-A-62-170950 is added. Can do. 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 recording layer coating solution.

[Support]
The support used in the lithographic printing plate precursor according to the present invention is a dimensionally stable plate-like material, and is not particularly limited as long as it satisfies physical properties such as required strength and flexibility. , Paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper laminated with or vapor-deposited metal as described above, or plastic film.

  As the support that can be applied to the present invention, a polyester film or an aluminum plate is preferable. Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.

  Thus, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and used aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used and cannot be specified. However, in general, the concentration of the electrolyte is 1 to 80% by mass, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm. ^{2. A} voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the lithographic printing plate precursor is easily damaged, and ink adheres to the damaged part during printing. The so-called “scratch stain” is likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

(Undercoat layer)
The lithographic printing plate precursor according to the invention is provided with a recording layer as described above on a support. If necessary, an undercoat layer can be provided between the support and the recording layer.
By providing this undercoat layer, the undercoat layer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the exposure of the infrared laser does not diffuse to the support and is used efficiently. There is an advantage that high sensitivity can be achieved. In addition, since the recording layer in the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, the sensitivity to the infrared laser is maintained well.
In the unexposed area, the recording layer itself that is impermeable to the alkali developer functions as a protective layer for the undercoat layer, so that an image with excellent development stability and excellent discrimination is obtained. It can be formed and stability over time is also ensured.
Furthermore, since the undercoat layer is a layer mainly composed of an alkali-soluble polymer and has a very good solubility in a developer, by providing such an undercoat layer adjacent to the support, for example, Even when a developer with reduced activity is used, when the components of the photosensitive layer whose dissolution-inhibiting ability has been released by exposure are dissolved and dispersed in the developer, no residual film or the like is generated promptly. The exposed portion is removed. This is considered to contribute to the improvement of developability. For these reasons, the undercoat layer is considered useful.

  Various organic compounds are used as the undercoat layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, phenylphosphonic acid which may have a substituent, Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloride of triethanolamine Hydroxy groups such as Selected from hydrochloride of the amine to be, but may be used by mixing two or more.

  In particular, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

In the above formula, R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl. Represents a group, —OR ¹⁴ , —COOR ¹⁵ , —CONHR ¹⁶ , —COR ¹⁷ or —CN, or R ¹² and R ¹³ may combine to form a ring, and R ^{14 to} R ¹⁷ are each independently X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, It represents an aryl group or a substituted aryl group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

Examples of suitable undercoat layer components in the lithographic printing plate precursor according to the present invention include polymer compounds having a component having an acid group and a component having an onium group, as described in JP-A No. 2000-241962. Can do. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. The acid group is preferably an acid group having an acid dissociation index (pKa) of 7 or more, more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium salt is an onium group comprising an atom of Group V or Group VI of the periodic table, more preferred is an onium salt comprising a nitrogen atom, a phosphorus atom or a sulfur atom, and particularly preferred is an onium salt comprising a nitrogen atom. It is salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds described in JP-A No. 2000-108538, Japanese Patent Application No. 2002-257484, Japanese Patent Application No. 2003-78699, and the like can be used as necessary.

Such an undercoat layer can be provided by the following method. That is, a method in which a solution prepared by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is applied on an aluminum plate (support) and dried, and water or methanol, An aluminum plate (support) is immersed in a solution in which the above organic compound is dissolved in an organic solvent such as ethanol or methyl ethyl ketone, or a mixed solvent thereof, to adsorb the above compound, and then washed and dried with water or the like to undercoat. This is a method of providing a layer.
In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.
The coating amount of the undercoat layer is suitably ² to 200 mg / m ² from the viewpoint of printing durability, and preferably 5 to 100 mg / m ² .

[Plate making process of lithographic printing plate precursor]
(exposure)
The planographic printing plate precursor of the present invention is image-formed by heat. Specifically, for this image formation, direct image-like recording with a thermal recording head or the like, scanning exposure with an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, etc. are used, but the wavelength is 700 to 1200 nm. Exposure with a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared light is suitable.

The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy applied to the recording material is preferably 10 to 500 mJ / cm ² .

(developing)
The developer that can be applied to the lithographic printing plate precursor according to the invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used as the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. An aqueous solution called “silicate developer” having a pH of 12 or higher, and the other is a so-called “non-silicate developer” that does not contain alkali silicate and contains a non-reducing sugar (an organic compound having a buffering action) and a base. It is.

In the former, the aqueous solution of alkali metal silicate is a ratio of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]. ) And the density, the developability can be adjusted. For example, as disclosed in JP-A-54-62004, the SiO ₂ / Na ₂ O molar ratio is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4 mass% is disclosed in JP-B-57-7427. As described, [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and SiO ₂ The developer is based on gram atoms of all alkali metals present in the developer. A manner containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  In addition, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base is more preferable for application to the development of a lithographic printing plate precursor according to the present invention. When this developer is used to develop the lithographic printing plate precursor, the surface of the recording layer is not deteriorated and the thickness of the recording layer can be maintained in a good state. In addition, the lithographic printing plate precursor generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. Further, the effect of improving discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention is mild, and the difference between the exposed and unexposed areas is likely to occur.

  The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

  Examples of the trehalose type oligosaccharides include saccharose and trehalose. 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-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable in that they have a buffering action in an appropriate pH region and are inexpensive.

  These non-reducing sugars may be used alone or in combination of two or more. The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass from the viewpoint of promoting high concentration and availability.

  Examples of the base used in combination with the non-reducing sugar include conventionally known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

  Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.

  The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable. In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

  In addition, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in Ionization Constants of Organic Acids Solution issued by Pergmon Press.

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (and the like) , Salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m Compounds having a phenolic hydroxyl group such as-, p-cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine , Ki Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  In the developer and replenisher, various surfactants and organic solvents are added as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or enhancing ink affinity of the printing plate image area. Can be added. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acid, antifoaming agent, hard water, if necessary. Softeners and the like can be added.

  The lithographic 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 post-processing, these processes can be used in various combinations.

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 the developer can be obtained without replacing the developer in the developer tank for a long time. It is known that PS plates 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 replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving 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, 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 water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the printing plate precursor according to the present invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. A developing solution is sprayed from a spray nozzle. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll in a processing liquid tank filled with the processing liquid. 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.

  In the present invention, when there is an unnecessary image portion (for example, a film edge mark of the original film) on the planographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming. The unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to make a lithographic printing plate with a higher printing durability, if desired, Burning process is performed.
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 in which the printing plate is immersed and applied 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-adjusting solution 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 In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted. 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 this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.
[Examples 1 and 2 , Comparative Example 1]
(Production of support)
Using a JIS-A-1050 aluminum plate having a thickness of 0.3 mm, a support was produced by processing through the following steps.

(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to perform an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

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

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has 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 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

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

(G) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkali etching treatment The aluminum plate was sodium hydroxide concentration of 26 wt%, performed an aluminum ion concentration of 6.5 wt% to etching treatment by spraying at 32 ° C., the aluminum plate 0.10 g / m ² was dissolved, the alternating current in the previous stage The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

<Support A>
The steps (a) to (j) were sequentially performed, and the support A was produced so that the etching amount in the step (e) was 3.4 g / m ² .
<Support B>
A support B was prepared by sequentially performing the steps except that the steps (g), (h), and (i) were omitted.

<Support C>
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.
<Support D>
Except for omitting the process of the above step (a) and (d) (e) (f ) performs the steps in turn, supported as total amount of electricity is 450C / dm ² in step (g) Body D was prepared.
The following supports A, B, C and D were then subjected to the following hydrophilic treatment and undercoating treatment.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment was immersed in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silica. Acid salt treatment (silicate treatment) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

[Undercoating]
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds to form an undercoat layer. The coating amount after drying was 15 mg / m ² .

(Undercoat liquid)
・ 0.3 g of the following polymer compound (I or II below)
・ Methanol 100g
・ Water 1g

[Formation of recording layer]
Next, after applying the lower layer coating liquid A having the following composition to the support with the undercoat layer obtained above (the type of support is shown in Table 1 below) with a wire bar, the temperature is 140 ° C. The coating amount was 0.85 g / m ² by drying in a drying oven for 50 seconds.
Subsequently, the uppermost layer coating liquid B having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain positive lithographic printing plate precursors of Examples 1 and 2 and Comparative Example 1 with a total coating amount of 1.07 g / m ² .

<Coating liquid A for lower layer>
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate 2.13 g
(Molar ratio 36:34:30, weight average molecular weight 50,000)
・ Cyanine dye P (structure shown below) 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
2-methoxy-4- (N-phenylamino)
Benzenediazonium hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
・ Fluorine-based surfactant 0.023g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Γ-Butyrolactone 13.16g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Coating solution B for top layer>
-Specific sulfonium salt or comparative sulfonium salt described in Table 1 below 0.08 g
・ 0.341 g of m-cresol / p-cresol novolac resin
(Molar ratio 60:40, weight average molecular weight 5,000)
・ Cyanine dye P (the above structure) 0.019 g
・ Fluorine surfactant 0.004g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Fluorine surfactant 0.001g
(Megafuck F-781, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

[Examples 3 to 4 and Comparative Example 2]
A recording layer coating solution C having the following composition was applied to a support with an undercoat layer obtained in the same manner as in Examples 1 and 2 (the type of support is shown in Table 1 below) with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain a positive lithographic printing plate precursor of Examples 3 to 4 and Comparative Example 2 with a total coating amount of 1.80 g / m ² .

<Recording layer coating solution C>
-Specific sulfonium salt or comparative sulfonium salt described in Table 1 below 0.100 g
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate 0.75g
(Molar ratio 36:34:30, weight average molecular weight 50,000)
・ M-cresol / p-cresol novolak resin 0.25 g
(Molar ratio 60:40, weight average molecular weight 5,000)
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Cyanine dye P (the above structure) 0.017 g
・ Victorious Pure Blue 0.015g
(Dye whose BOH counter anion is 1-naphthalenesulfonic acid anion)
・ Fluorosurfactant 0.05g
(Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Γ-Butyllactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

[Examples 5 to 6 , Comparative Example 3]
A recording layer coating solution D having the following composition was applied to a support with an undercoat layer obtained by the same method as in Examples 1 and 2 with a wire bar. After coating, drying was performed at 150 ° C. for 100 seconds to obtain positive lithographic printing plate precursors of Examples 5 to 6 and Comparative Example 3 with a total coating amount of 1.40 g / m ² .

<Recording layer coating solution D>
-Specific sulfonium salt or comparative sulfonium salt described in Table 1 below 0.100 g
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate 2.072g
(Molar ratio 36:34:30, weight average molecular weight 50,000)
・ Cyanine dye P (the above structure) 0.052 g
・ Fluorine-based surfactant 0.017g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
・ Methyl ethyl ketone 25.30g

[Evaluation of lithographic printing plate precursor]
The performance evaluation of the positive type lithographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3 was performed.
Note that the evaluation test was conducted for a sample stored at 25 ° C. for 30 days after coating for forming the recording layer.

(Evaluation of sensitivity)
The obtained positive lithographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3 were drawn solid images at a drum rotation speed of 250 rpm while gradually changing the beam intensity with a Trend setter 800 manufactured by Creo. After that, Fuji was charged with a water dilution (1: 8) solution of developer DT-2 manufactured by Fuji Photo Film Co., Ltd. and a water dilution (1: 1) solution of finisher FG-1 manufactured by Fuji Photo Film Co., Ltd. Using a PS processor LP-940HII manufactured by Photo Film Co., Ltd., development was performed at a developing time of 12 seconds while maintaining the liquid temperature at 30 ° C. Then, the developed plate was observed with a magnifying glass of 50 times, and the exposure beam intensity where no pot-like residual film was observed was taken as sensitivity.
At this time, the smaller the exposure energy amount, the higher the sensitivity. The results are shown in Table 1.

(Evaluation of development residue)
The obtained positive type planographic printing plate precursors of Examples 1 to 6 and Comparative Examples 1 to 3 were drawn with a solid image at a beam intensity of 10 W and a drum rotation speed of 250 rpm on a Trend setter 800 manufactured by Creo, Fuji Photo A solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Film Co., Ltd. in a water dilution (1: 9) until the electric conductivity reached 37 mS / cm and water of the finisher FG-1 manufactured by Fuji Photo Film Co., Ltd. Using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd. with a diluted (1: 1) solution, the solution temperature was maintained at 30 ° C. and development was performed for 12 seconds.
After this development was performed for a total processing area of 100 m ² , the developer in the automatic developing machine was collected in a transparent bottle, and the presence or absence of development residue after standing at room temperature for 12 hours was visually compared. The evaluation was evaluated as を when almost no development debris could be confirmed, ◯ when almost no debris was confirmed, and x when large amounts of development debris were observed. The results are shown in Table 1.

[Solubility of sulfonium salt]
The solubility of each sulfonium salt used in the examples and comparative examples was measured as follows.
That is, under a condition of 25 ° C. and 1 atm, 50 ml of 0.1 mol / L NaOH aqueous solution is put in a glass that can be clearly seen, and 50 mg of a sulfonium salt is added and stirred for 5 minutes while keeping the temperature at 25 ° C. and sealing. The solubility was confirmed. Thereafter, if the sulfonium salt was completely dissolved, 50 mg of the sulfonium salt was further added and stirred for 5 minutes, and the solubility was confirmed again. This operation was continued until the sulfonium salt was not dissolved, and the concentration of the sulfonium salt when the amount of dissolution was maximized was defined as the solubility. The measurement results are also shown in Table 1.

Here, the number (No.) indicating the specific sulfonium salt described in Table 1 is a number assigned to the specific sulfonium salt of the specific example.
Moreover, the structure of the comparative sulfonium salt (SA, SB, and SC) used for the comparative example is shown below.

As is apparent from Table 1, the lithographic printing plate precursors of Examples 1 to 6 provided with the recording layer containing the specific sulfonium salt in the present invention are all excellent in sensitivity, and the development residue is generated. I can't see it.
On the other hand, the lithographic printing plate precursors (Comparative Examples 1 to 3) provided with a recording layer containing a comparative sulfonium salt that is out of the solubility range of the present invention have low sensitivity and a large amount of development residue is observed. I understand.

Claims (4)

A sulfonium salt having a recording layer containing an alkali-soluble resin, an infrared absorber, and a sulfonium salt on a support, the sulfonium salt having three phenyl groups having an alkali-soluble group as a substituent at the cation portion , and the and at normal temperature and pressure, in 0.1 mol / L, and the lithographic printing plate precursor solubility NaOH aqueous solution temperature 25 ° C. is characterized in that at 25 mg / ml or more. The lithographic printing plate precursor as claimed in claim 1, wherein the alkali-soluble group is a carboxy group or a hydroxyl group. The lithographic printing plate precursor according to claim 1, wherein the alkali-soluble group is a hydroxyl group. The lithographic printing plate precursor as claimed in claim 1, wherein the alkali-soluble group is a carboxy group.