JP2006150939A - Original printing plate for lithographic printing plate, method for manufacturing original printing plate for lithographic printing plate and method for printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original printing plate of an on-machine developing type or processing-less (development-less) type lithographic printing plate capable of easily identifying a printing plate after exposure to light and suppressing generation of fogging of an image printed out with time or by exposure by a white lamp and color cloudiness of a printed article, a method for manufacturing the original printing plate of the lithographic printing plate, and a method for printing using the original printing plate for the lithographic printing plate. <P>SOLUTION: The original printing plate for the lithographic printing plate has an image recording layer on a substrate, and is capable of printing without passing through a development processing process after exposing to the light into an image-like pattern. The original printing plate for the lithographic printing plate is characterized by that it comprises (A) an infrared rays absorbing agent, (D) a color changing agent, and (E) a color developing agent, and the color changing agent is a particle, which melts by a heat generated by exposure to the light and generates a change in absorbance in a visible light region by interaction with the color developing agent. The method for manufacturing the original printing plate for the lithographic printing plate wherein after coating with a coating liquid in which the color changing agent is dispersed in a particulate state, drying is performed under a condition that the particle of the color changing agent does not melt, and the method for printing using this original printing plate for the lithographic printing plate, are disclosed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor that can be printed after exposure without undergoing a development processing step. Specifically, it is a lithographic printing plate precursor that can be directly made by scanning an infrared laser based on a digital signal from a computer or the like, and can be printed on-machine development type that can be printed without being subjected to a development processing step after exposure. The present invention relates to an unprocessed (no development) type lithographic printing plate precursor, a method for producing the lithographic printing plate precursor, and a printing method using the lithographic printing plate precursor.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Normally, after exposing a lithographic printing plate precursor through an original image such as a lithographic film, the image recording layer in the image area remains, and the image recording layer in the non-image area is dissolved with an alkaline developer or an organic solvent. The lithographic printing plate is obtained by carrying out plate making by a method of exposing the surface of the hydrophilic support by removing it.

  In the conventional plate-making process of a lithographic printing plate precursor, a step of dissolving and removing the non-image area with a developing solution or the like corresponding to the image recording layer is necessary after exposure. One of the problems is to make the system unnecessary or simplified. In particular, in recent years, disposal of waste liquids discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and therefore, the demand for solving the above-mentioned problems has become stronger.

  In contrast, a non-processing (non-developing) type that eliminates the need for wet processing has an image recording layer whose affinity for dampening water or ink changes on the surface by exposure, and is accompanied by removal of the image recording layer. A lithographic printing plate precursor that can be printed without any problem has been proposed.

In addition, as one of the simple plate making methods, an image recording layer that can remove the non-image area of the lithographic printing plate precursor in the normal printing process is used. After exposure, the non-image area is removed on the printing press. A method called on-press development for obtaining a lithographic printing plate has been proposed.
As a specific method of on-press development, for example, a method of using a lithographic printing plate precursor having an image recording layer that can be dissolved or dispersed in dampening water, an ink solvent, or an emulsion of dampening water and ink , A method of mechanically removing the image recording layer by contact with rollers or a blanket cylinder of a printing press, cohesion of the image recording layer by penetration of dampening water, ink solvent, etc. There is a method in which after the adhesive force is weakened, the image recording layer is mechanically removed by contact with rollers or a blanket cylinder.
In the present invention, unless otherwise specified, the “development process step” refers to using a device other than a printing press (usually an automatic developing machine) and bringing a liquid (usually an alkaline developer) into contact therewith. Refers to the step of removing the unexposed portion of the lithographic printing plate precursor from the infrared laser to expose the surface of the hydrophilic support, and “on-press development” refers to a process using a printing machine (typically printing ink and / or printing ink). Or a dampening solution) to remove the infrared laser unexposed portion of the lithographic printing plate precursor and expose the surface of the hydrophilic support.

  However, when an image recording layer of a conventional image recording system using ultraviolet rays or visible light is used, the image recording layer does not fix even after exposure. For example, the lithographic plate after exposure until it is mounted on a printing press. It was necessary to take a time-consuming method such as storing the printing plate precursor completely in a light-shielded state or under constant temperature conditions.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  As described above, in recent years, the simplification, drying, and no processing of plate making operations have become more desirable than ever in terms of consideration for the global environment and adaptation to digitalization. It is coming.

Recently, high-power lasers such as semiconductor lasers and YAG lasers that emit infrared light with a wavelength of 760 to 1200 nm have become available at low cost. As a method for producing lithographic printing plates by scanning exposure that is easy to incorporate into digitization technology. Therefore, a method using these high-power lasers as an image recording means has been promising.
In the conventional plate-making method, imagewise exposure is performed on a photosensitive lithographic printing plate precursor at low to medium illuminance, and image recording is performed by image-like physical property change due to a photochemical reaction in an image recording layer. In contrast, in the method using the above-described high-power laser, a large amount of light energy is irradiated to the exposure region in an extremely short time, and the light energy is efficiently converted into heat energy. In the process, a thermal change such as a chemical change, a phase change, a change in form or structure is caused, and the change is used for image recording. Accordingly, image information is input by light energy such as laser light, but image recording is performed in a state in which reaction by heat energy is taken into account in addition to light energy. Usually, such a recording method using heat generated by high power density exposure is called heat mode recording, and changing light energy to heat energy is called photothermal conversion.

  The major advantages of the plate making method using heat mode recording are that the image recording layer is not exposed to light at a normal illuminance level such as indoor lighting, and that fixing of images recorded by high illuminance exposure is not essential. is there. That is, the lithographic printing plate precursor used for heat mode recording is not likely to be exposed to room light before exposure, and image fixing is not essential after exposure. Therefore, for example, if an image recording layer that is insolubilized or solubilized by exposure using a high-power laser is used, and the plate making process in which the exposed image recording layer is imaged to form a lithographic printing plate is performed by on-machine development, exposure is performed. Later, a printing system is possible in which the image is not affected even if it is exposed to ambient light in the room. Therefore, if heat mode recording is used, it is expected that a lithographic printing plate precursor suitably used for on-press development can be obtained.

On the other hand, for example, Patent Document 1 describes a lithographic printing plate precursor in which an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. Yes. In this Patent Document 1, the above lithographic printing plate precursor is exposed by an infrared laser, and the hydrophobic thermoplastic polymer particles are coalesced by heat to form an image, which is then mounted on a cylinder of a printing press and moistened. It is described that it is possible to perform on-press development with water and / or ink.
However, it has been found that the above-described method for forming an image by merging the fine particles by simple thermal fusion exhibits good on-press developability but has low image strength and insufficient printing durability.

For this reason, it has been proposed to improve printing durability using a polymerization reaction. For example, Patent Document 2 describes a lithographic printing plate precursor having an image recording layer (thermosensitive layer) containing microcapsules encapsulating a polymerizable compound on a hydrophilic support. Furthermore, Patent Document 3 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support.
Japanese Patent No. 2938397 JP 2001-277740 A JP 2002-287334 A

In general, as a pre-process for attaching a printing plate to a printing press, the work of inspecting and identifying the image on the printing plate, such as whether the printing plate is image-recorded as intended, and what color ink plate is used Done. Ordinary lithographic printing plates with a development process are generally used to check the image after plate making (after development) and before printing (before attaching the printing plate to the printing press) by coloring the image recording layer. It is easy to do.
However, in an on-press development type or unprocessed (no development) type lithographic printing plate precursor that does not involve a development processing step before printing, there is no image on the printing plate when the printing plate is attached to the printing press. Cannot be identified. As a result, work mistakes may occur. In particular, whether or not it is possible to determine whether or not a register mark (register mark) serving as a registration mark in multi-color printing is clearly drawn is important for the printing work. Further, when the printout image has plate discrimination, it is desirable that the printout image is not fogged when exposed to white light over time or in order to obtain clear discrimination. Furthermore, in the on-press development type lithographic printing plate precursor, components removed by on-press development are mixed in dampening water or ink, but the components that form a printout image do not cause color turbidity in the printed matter. is necessary.

  The present invention solves these problems. That is, an object of the present invention is to make it easy to identify a plate after exposure, and to prevent on-image development type or no processing (no development) in which print-out image fogging due to aging or white light exposure and generation of color turbidity are suppressed. ) Type lithographic printing plate precursor, a method for producing the lithographic printing plate precursor, and a printing method using the lithographic printing plate precursor.

  As a result of intensive studies, the present inventors have found that a color-changing agent capable of causing a change in absorbance in the visible light region due to the interaction with the developer is present in the form of particles and is melted by heat during exposure. It has been found useful and has led to the present invention. That is, the present invention is as follows.

  1. A lithographic printing plate precursor having an image recording layer on a support and capable of being printed without being subjected to a development processing step after being imagewise exposed, comprising (A) an infrared absorber and (D) a color change agent And (E) a developer, and the color changer is a particle, and melts with heat generated by exposure and interacts with the developer to cause a change in absorbance in the visible light region. A lithographic printing plate precursor.

  2. 2. The lithographic printing plate precursor as described in 1 above, wherein the image recording layer comprises (A) an infrared absorber, (B) a polymerization initiator, and (C) a polymerizable compound.

  3. 2. The lithographic printing plate precursor as described in 1 above, wherein the image recording layer comprises (A) an infrared absorber and (F) hydrophobic thermoplastic polymer particles.

  4). The lithographic printing plate precursor as described in any one of 1 to 3 above, wherein the image recording layer is a crosslinked hydrophilic layer.

  5. The lithographic printing plate precursor as described in any one of 1 to 4 above, wherein the image recording layer contains a microcapsule or a microgel.

  6). A method for producing a lithographic printing plate precursor that is image-wise exposed and can be printed without undergoing a development process, and melts with the heat generated by the exposure and interacts with the developer in the visible light region. Production of a lithographic printing plate precursor comprising dispersing a color changing agent causing a change in absorbance in the form of a coating solution containing a color developer, applying the liquid, and then drying under a condition that the color changing agent particles do not melt. Method.

7). A printing method comprising the following steps.
(1) A step of imagewise exposing the lithographic printing plate precursor as described in any one of 1 to 5 above.
(2) A step of mounting the lithographic printing plate precursor on a plate cylinder of a printing machine.
(3) A step of printing by supplying printing ink and fountain solution onto the exposed lithographic printing plate precursor on the printing plate cylinder.
However, the steps (1) and (2) may be performed in reverse order.

  In the present invention, by using a color changer and a color developer and making the color change agent present in the form of particles, it is possible to enable good discrimination and suppression of fogging and turbidity of printed matter due to aging or white light. It was. This effect is considered to be due to the fact that by making the color change agent in particulate form, the contact between the color change agent and the color developer is reduced and the interaction can be suppressed except that the color change agent melts due to heat generated by exposure.

  According to the present invention, the plate after exposure can be easily identified, and the on-press development type or no processing (non-development) which suppresses the occurrence of print-out fogging and color turbidity on printed matter due to aging or white light exposure. A lithographic printing plate precursor of a mold, a method for producing the lithographic printing plate precursor, and a printing method using the lithographic printing plate precursor can be provided.

  The lithographic printing plate precursor that can be mounted on a printing press without undergoing a development processing step after image recording of the present invention, or image-recorded after mounting of the printing press and printed, is shown below (1) On-press Examples thereof include a development type lithographic printing plate precursor and (2) an untreated (no development type) lithographic printing plate precursor.

(1) On-press development type lithographic printing plate precursor:
An image recording layer in which the solubility or dispersibility in fountain solution and / or ink is changed by exposure, or the adhesiveness to adjacent layers having different affinity for fountain solution or ink is changed by exposure. A lithographic printing plate precursor that can be developed by supplying dampening water and / or ink to the printing plate on the printing press after exposure.
(2) Unprocessed (non-developable) lithographic printing plate precursor:
A lithographic printing plate precursor having an image recording layer whose affinity for fountain solution or ink is changed on the surface by exposure, and printing is possible without removing the image recording layer after image exposure.

  The lithographic printing plate precursor that can be mounted on a printing press without undergoing a development processing step after image recording of the present invention, or image-recorded after mounting of the printing press and can be printed, includes the above (1) and (2). There is no particular limitation as long as it is a lithographic printing plate precursor.

Specifically, Japanese Patent No. 2938397, Japanese Patent Laid-Open No. 2001-277740, Japanese Patent Laid-Open No. 2001-277742, Japanese Patent Laid-Open No. 2002-287334, Japanese Patent Laid-Open No. 2001-96936, Japanese Patent Laid-Open No. 2001-96938, Japanese Patent Laid-Open No. 2001 -180141, JP-A-2001-162
960 publications, WO 00/16987, WO 01/39985 pamphlets, European Patent Application Publication No. 990517, European Patent Application Publication No. 1225041, US Pat. No. 6,465,152 JP-A-6-317899, International Publication No. 96/35143 pamphlet, European Patent Application Publication No. 652483, JP-A-10-10737, JP-A-11-309952, US Pat. No. 6,176,777. And plate materials described in US Pat. No. 6,413,694.
The components of the lithographic printing plate precursor and the method for producing the lithographic printing plate precursor of the present invention will be described in detail below.

[Discoloring agent and developer]
As a system (color change system) of a color changing agent and a color developing agent in which an absorbance change in the visible light region is caused by exposure used in the present invention, the color changing agent itself does not change color even when energy is applied, but contacts the color developing agent. The thing which interacts by this and raise | generates the light absorbency change of visible region is mentioned.

  In the present invention, a layer containing a system of a color changing agent and a color developer is referred to as a color changing layer, but the color changing layer is not limited to other functions that constitute the lithographic printing plate precursor of the present invention unless it loses its function. It may be the same layer as the image recording layer, protective layer, undercoat layer or other intermediate layer.

  Examples of the color changer / developer system include various systems that change color between two or more components by acid-base reaction, oxidation-reduction reaction, coupling reaction, chelate formation reaction, and the like. For example, color developing systems consisting of acidic substances (developers) such as acid clay and phenols, using color formers with partial structures such as lactones, lactams and spiropyrans used in pressure sensitive paper as color-changing components, aromatic diazonium System using azo coupling reaction such as salt, diazotate, diazosulfonates and naphthols, anilines, active methylenes, reaction of hexamethylenetetramine with ferric ion and gallic acid and phenolphthalein complexone A chelate forming reaction such as a reaction between an acid and an alkaline earth metal ion, a redox reaction such as a reaction between ferric stearate and pyrogallol, or a reaction between silver behenate and 4-methoxy-1-naphthol can be used.

  The color former in the color former / developer system includes (i) triarylmethane, (ii) diphenylmethane, (iii) xanthene, (iv) thiazine, (v) spiropyran, (vi) spirooxazine. Specific examples thereof include those described in JP-A No. 58-27253. Of these, (i) triarylmethane-based, (iii) xanthene-based, (v) spiropyran-based, and (vi) spirooxazine-based color formers are preferred because they have little fog and give a high color density.

Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 3- (N, N-diethylamino) -6-chloro-7- (β-ethoxyethylamino) -fluorane, 3- (N, N, N-triethylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -7-chloro-7-o-chlorofluorane, 2- (N-phenyl-N-methylamino) ) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino-3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) -fluorane, 3- (N-cyclohexyl-N-methyla) C) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7 -Xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chlorofluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N
-Diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutylamino) -6-methyl-7-anilinofluorane 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilino Fluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl-2-methylindol-3-yl) phthalide, 3,3 -Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4 Zafutarido, 3- (4-diethylamino-phenyl) -3- (1-ethyl-2-methylindole-3-yl) phthalide and the like.

  Specific examples of the spiropyran-based and spirooxazine-based compounds include, but are not limited to, the following.

  1 ′, 3′-dihydro-1 ′, 3 ′, 3′-trimethylspiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1 ′, 3′-dihydro-8-methoxy-1 ', 3', 3'-trimethylspiro [2H-1-benzopyran-2,2 '-(2H) indole], 6-bromo-1', 3'-dihydro-1 ', 3', 3'-trimethyl Spiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1 ′, 3′-dihydro-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2, 2 ′-(2H) indole], 1 ′, 3′-dihydro-8-methoxy-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2 ′-(2H) Indole], 1 ′, 3′-dihydro-5′-meth Ci-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1 ′, 3′-dihydro-8-methoxy-5′-methyl Sulfonyl-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1 ′, 3′-dihydro-3 ′, 3′-dimethyl- 1- (3-sulfopropyl) -6-nitrospiro [2H-1-benzopyran-2,2 ′-(2H) indole] triethylamine salt, 1 ′, 3′-dihydro-3 ′, 3′-dimethyl-6 Nitro-1′-octadecylspiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1 ′, 3′-dihydro-3 ′, 3′-dimethyl-6-nitro-1′-octadecyl- 8-Dodesanoy Oxymethylspiro [2H-1-benzopyran-2,2 ′-(2H) indole], 1,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3 ′-[3H] naphtho [ 2,1-b]-[1,4] oxazine], 1 ′, 3′-dihydro-1 ′, 3 ′, 3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2 ′-[ 2H] indole], 1,3-dihydro-3,3-dimethyl-1-octadecylspiro [2H-indole-2,3 ′-[3H] naphtho [2,1-b]-[1,4] oxazine] 1,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3 ′-[3H] phenanthro [9,10-b] [1,4] oxazine], 5-chloro-1, 3-dihydro-1,3,3-trimethylspi [2H-indole-2,3 ′-[3H] naphtho [2,1-b]-[1,4] oxazine], 5-chloro-1,3-dihydro-1,3,3-trimethylspiro [ 2H-indole-2,3 ′-[3H] phenanthro [9,10-b] [1,4] oxazine] and the like.

  The said compound is used individually or in mixture.

  As the developer, a phenol compound, an organic acid, an inorganic acid, a metal salt thereof, an oxybenzoic acid ester, an acidic clay, or the like is used.

Specific examples of phenolic compounds include phenol, various cresols, p-nitrophenol, 4,4′-isopropylidene-diphenol (bisphenol A), p-tert-butylphenol, 2,4-dinitrophenol, 3,4 -Dichlorophenol, 4,4'-methylene-bis (2,6-di-tert-butylphenol), p-phenylphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4
-Hydroxyphenyl) -2-ethylhexane, 2,2-bis (4-hydroxyphenyl) butane, 2,2'-methylenebis (4-tert-butylphenol), 2,2'-methylenebis (α-phenyl-p- Cresol) thiodiphenol 4,4′-thiobis (6-tert-butyl-m-cresol), sulfonyldiphenol, p-tert-butylphenol-formalin condensate, p-phenylphenol-formalin condensate, etc. It is done.

Organic acids, inorganic acids, and metal salts thereof include acetic acid, phthalic acid, phthalic anhydride, maleic acid, benzoic acid, gallic acid, o-toluic acid, p-toluic acid, salicylic acid, 3-tert-butylsalicylic acid, 3,5-di-3-tert-butylsalicylic acid, 5-α-methylbenzylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 3-tert-octylsalicylic acid, methanesulfonic acid, p-toluenesulfonic acid , Trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, phenylphosphonic acid, HF, HCl, HBr, HI, HClO ₄ , HBF ₄ , HPF ₆ , HSbF ₆ , AsF ₆ , H ₃ PO ₃ , H ₃ PO ₄ , H _{2 SO 3, H 2 SO 4} , HNO 3 and its zinc salt, lead salt, aluminum salt, magnesium salt, nickel salt, Na Potassium salt, potassium salt and the like. In particular, salicylic acid derivatives and zinc salts or aluminum salts have excellent color developing ability. Examples of the oxybenzoate include ethyl p-oxybenzoate, butyl p-oxybenzoate, heptyl p-oxybenzoate, and benzyl p-oxybenzoate.

  Other color formers / developer color developers include, for example, phenolphthalein, fluorescein, 2,4,5,7-tetrabromo-3,4,5,6-tetrachlorofluorescein, tetrabromo Phenol blue, 4,5,6,7-tetrabromophenolphthalein, eosin, aurin resole red, 2-naphthol phenolphthalein and the like can be mentioned.

  Developers include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines , Nitrogen-containing compounds such as triazoles, morpholines, piperidines, amidines, formazines and pyridines.

  Specific examples of these include, for example, ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, allylurea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, 2-benzylimidazole, 4-phenyl. Imidazole, 2-phenyl-4-methylimidazole, 2-undecyl-imidazoline, 2,4,5-trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-2-imidazoline, 2-phenyl-2 -Imidazoline, 1,2,3-triphenylguanidine, 1,2-ditolylguanidine, 1,2-dicyclohexylguanidine, 1,2-dicyclohexyl-3-phenylguanidine, 1,2,3-tricyclohexylguanidine, guanidine Rikuroro acetate, N, N'-di-benzylpiperazine, 4,4'-dithio morpholine, morpholinium trichloroacetic acid salts, 2-aminobenzothiazole, 2-benzoyl-hydrazino - there is benzothiazole.

  In addition to the above, the developer component that changes the color-changing agent may be an acid, a base, or a radical that is generated by applying energy such as light irradiation, heating, or pressurization. For this purpose, an acid generator or a base generator that generates an acid, a base, or a radical by heat generated from an infrared absorbent that has absorbed laser light or an electron or energy transfer from the infrared absorbent by infrared laser exposure. Or a radical generator is preferably contained in the discoloration layer.

  Examples of the color changing agent that changes color by interacting with at least one of acid, base, and radical include diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminonaphthoquinone, azomethine, etc. Are effectively used.

  Specific examples include brilliant green, eosin, ethyl violet, erythrosine B, methyl green, crystal violet, basic fuchsin, phenolphthalein, 1,3-diphenyltriazine, alizarin red S, thymolphthalein, methyl violet 2B, quinaldine. Red, rose bengal, methanyl yellow, thymolsulfophthalein, xylenol blue, methyl orange, orange IV, diphenylthiocarbazone, 2,7-dichlorofluorescein, paramethyl red, congo red, benzopurpurin 4B, α-naphthyl Red, Nile Blue 2B, Nile Blue A, Phenacetalin, Methyl Violet, Malakide Green, Parafuchsin, Victoria Pure Blue BOH [Hodogaya Gaku Kogyo Co., Ltd.], Oil Blue # 603 [Orient Chemical Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [manufactured by Orient Chemical Co., Ltd.], Oil Red OG [manufactured by Orient Chemical Industry Co., Ltd.], Oil Red RR [manufactured by Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.] Spiron Red BEH Special [Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, first acid violet R, sulforhodamine B, auramin, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p-diethyl Aminophenyliminonaphthoquinone, 2-carbostearylamino-4-p-dihydrooxyethylamino-phenyliminonaphthoquinone, p-methoxybenzoyl-p'-diethylamino-o'-methylphenyliminoacetanilide, cyano-p-diethylaminophenyliminoacetanilide 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4-p-diethylaminophenylimino-5-pyrazolone, and the like.

  In addition to the above, compounds shown as color formers in the color former / developer system can also be used effectively.

  Moreover, organic compounds of arylamines can be used as compounds that develop color with radicals. Suitable arylamines for this purpose include so-called leuco dyes in addition to simple arylamines such as primary and secondary aromatic amines. These compounds come into contact with free radicals generated from the radical generator activated in the exposed area, and generate a colored image on an uncontacted background (ground). Examples of these compounds include the following.

  Examples of mere arylamines include diphenylamine, dibenzylaniline, triphenylamine, diethylaniline, diphenyl-p-phenylenediamine, p-toluidine, 4,4'-biphenyldiamine, o-chloroaniline, o-bromoaniline, 4-chloro-o-phenylenediamine, o-bromo-N, N-dimethylaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, aniline, 2,5-dichloroaniline, N-methyldiphenylamine, o -Toluidine etc. are mentioned.

Examples of the leuco dye include leuco dyes described in US Pat. No. 3,445,234. Aminotriarylmethanes, aminoxanthenes, aminothioxanthenes, amino-9,10-dihydroacridines, aminophenoxazines, aminophenothiazines, aminodihydrophenazines, aminodiphenylmethanes, leucodamines, Aminohydrocinnamic acid (cyanoethane, leucometins), hydrazines, leucoin digoid dyes, amino-2,3-dihydroanthraquinones, tetrahalo-p, p'-biphenols, 2- (p-hydroxyphenyl) -4 , 5-diphenylimidazoles and phenethylanilines.

Of the above leuco dyes, aminotriarylmethane is particularly preferred. Generally preferred aminotriarylmethane types are those wherein at least two of the aryl groups are (a) R ₁ and R ₂ are each hydrogen, C ₁ -C ₁₀ alkyl, 2-hydroxyethyl, 1-cyanoethyl, or benzyl. An R ₁ R ₂ N-substituent in the para position relative to the bond to the methane carbon atom, such as a selected group, and (b) a lower alkyl (C is 1-4), a fluorine atom, a chlorine atom or A phenyl group having a group ortho to the methane carbon atom selected from the bromine atom, and the third aryl group may be the same as or different from the first two;
(A) Lower alkyl, lower alkoxy, chlorine atom, diphenylamino, cyano, nitro, hydroxy, fluorine atom or bromine atom, alkylthio, arylthio, thioester, alkylsulfone, arylsulfone, sulfonic acid, sulfonamide, alkylamide, arylamide Phenyl substituted with and the like;
(B) naphthyl which can be substituted with amino, di-lower alkylamino, alkylamino;
(C) pyridyl which can be substituted with alkyl;
(D) quinolyl; and (e) indolinylidene that can be substituted with alkyl;
More selected aminotriarylmethanes and their acid salt types.

Preferably, R ₁ and R ₂ are a hydrogen atom or an alkyl having 1 to 4 carbon atoms. Most preferably, all three aryl groups are the same.

  Specific examples of aminotriarylmethane include, but are not limited to:

  p, p'-tetramethyldiaminodiphenylmethane (leucomalachite green), p, p'-tetraethyldiaminodiphenylmethane, N, N-dimethyl-p-phenylenediamine, 1,2-dianilinoethylene, p, p ', p " -Hexamethyltriaminotriphenylmethane (leuco crystal violet), p, p ', p "-hexaethyltriaminotriphenylmethane, p, p'-tetramethyldiaminotriphenylmethane, p, p'-tetramethyldiamino Diphenylmethylimine, p, p ′, p ″ -triamino-o-methyltriphenylmethane, p, p ′, p ″ -triaminotriphenylcarbinol, p, p′-tetramethylaminodiphenyl-4-anilino Naphthylmethane, p, p ′, p ″ -triaminophenylmethane, , P ', p "- hexapropylphosphorustriamide triamino triphenyl methane.

  Examples of the photoacid generator used in the developer include JP-A-59-180543, JP-A-59-148784, JP-A-60-138539, JP-B-60-27673, JP-B-49-21601. Organic halogen compounds described in JP-A-63-58440, JP-B-57-1819, JP-A-53-133428, JP-A-55-32070, etc .; The diazonium salts and iodonium salts described in JP-B Nos. 54-14278, 51-56885, U.S. Pat. Nos. 3,708,296 and 3,835,002, A sulfonium salt can be used.

Of these photoacid generators, more preferred are JP-A-59-180543, 59-148784, 60-138539, JP-B-60-27673, and JP-A-6.
Trihaloalkyl compounds and halomethyltriazine compounds described in JP-A-3-58440, JP-B-57-1819, JP-A-53-133428, and JP-A-55-32070.

As these acid generators, an acid generator capable of generating an acid having an acid dissociation constant (pKa) at 25 ° C. of preferably 5 or less, more preferably 3 or less, still more preferably 1 or less, and particularly preferably −1 or less. Is preferred. Examples of such acids include R—COOH, R—SO. _Three H, R-SO ₂ H, R-PO _Three H ₂ , R-OPO _Three H ₂ , R-PO ₂ H ₂ , R-OPO ₂ H ₂ (R represents an optionally substituted hydrocarbon group having 1 to 30 carbon atoms), HF, HCl, HBr, HI, HClO _Four , HBF _Four , HPF ₆ , HSbF ₆ , AsF ₆ , H _Three PO _Three , H _Three PO _Four , H ₂ SO _Three , H ₂ SO _Four , HNO _Three Inorganic acids such as R-SO _Three H, R-PO _Three H ₂ , R-OPO _Three H ₂ , HClO _Four , HBF _Four , HPF ₆ Is preferred, R-SO _Three H, HClO _Four , HBF _Four , HPF ₆ R-SO having a hydrocarbon group substituted with a fluorine atom _Three H and HClO _Four Is particularly preferred.

  Although the preferable specific example of a photo-acid generator is given to the following, this invention is not limited to these.

  Examples of the compound that generates a base by light or heat used for the developer include a salt of a carboxylic acid and an organic base. A base precursor comprising a salt of a carboxylic acid and an organic base is disclosed in U.S. Pat. No. 3,493,374, British Patent 998,949, JP-A-59-180537, JP-A-61- Those described in Japanese Patent No. 51139 and US Pat. No. 4,060,420 can be used. Base precursors composed of salts of these carboxylic acids and organic bases are configured to release organic bases during use (heating).

As the compound that generates radicals by light or heat used for the developer, conventionally known compounds can be used as photopolymerization initiators. Conventionally, radical generators called photooxidants are also effective.
For example, benzoin, benzoin alkyl ether, organic halogen compounds (for example, tetrabromide described in US Pat. Nos. 3,042,515 and 3,502,476 and JP-A-2-44) Carbon, N-bromosuccinimide, tribromomethylsulfone, trihalomethyl heterocyclic compounds such as trihalomethyl-s-triazine compounds and trihalomethyloxadiazole compounds, α, α, α-trihaloacetophenone compounds, alkyl or arylsulfonyl chlorides , Alkyl or aryl sulfenyl chlorides, trihalomethyl sulfones, and the above-mentioned organic halogen compounds as effective photoacid generators, etc.), azide polymer described in Japanese Society of Photography Society 1968 Spring Research Presentation Abstract, page 55, US Patent No. 3,282,693 Azide compounds such as 2-azidobenzoxazole, benzoyl azide and 2-azidobenzimidazole described in the specification, and 3′-ethyl-1-methoxy-2-pyridothia described in US Pat. No. 3,615,568 Compounds such as cyanine perchlorate, 1-methoxy-2-methylpyridinium p-toluenesulfonate, and lophine dimer compounds such as 2,4,5-triarylimidazole dimer described in JP-B-62-39728, benzophenone, p -Aminophenyl ketone, polynuclear quinone, thioxanthone compound, aromatic tertiary amines and the like can be suitably used.
A polymerization initiator described later is also an effective radical generator.

  Of these, trihaloalkyl compounds and halomethyltriazine compounds are more preferred, and specific examples thereof include the above-mentioned exemplified compounds of photoacid generators.

  These radical generators can be used alone or in combination of two or more. Specific examples of these radical generators and preferred examples of combined use thereof are described in "UV / EB Curing Handbook-Raw Materials-", Kato Kiyomi (Polymer Press Society), pages 67-73, "UV / EB Curing Technology". Applications and Markets "supervised by Yoneho Tabata, edited by Radtech Research Association (CMC), pages 64 to 82, Japanese Patent Publication No. 6-42074, Japanese Patent Publication No. Sho 62-61044, Japanese Patent Publication No. Sho 60-35725, Examples thereof include those described in JP-A-2-287547.

  In the present invention, the color changing agent must be dispersed in the form of particles and contained in the color changing layer. As a result, the interaction between the color changing agent and the color developing agent is manifested only on the surface of the color changing agent particles, and it becomes possible for the most part of the color changing agent to interact with the color developing agent only when melted during exposure. A printout image having a large difference in absorbance can be obtained.

  The most common method for dispersing the color change agent in the color change layer is to disperse the color change agent in the color change layer coating solution and apply it. As a dispersion method used here, a general dispersion method of an organic pigment is favorably applied.

  Although the general dispersion method of an organic pigment is demonstrated, this invention is not restrict | limited by these description. Conventionally, organic pigments are supplied after drying by various methods after synthesis. Usually, it is dried from an aqueous medium and supplied as a powder. However, since water requires a large latent heat of vaporization for drying, a large amount of heat energy is given to dry it to form a powder. Therefore, the pigment usually forms an aggregate (secondary particle) in which primary particles are aggregated. It is not easy to make organic pigments forming such an aggregate into fine particles and disperse them in the image recording layer. Therefore, it is preferable to treat the organic pigment with various resins in advance. Examples of these resins include organic linear polymer binders. Examples of the treatment method include a flushing treatment and a kneading method using a kneader, an extruder, a bead mill, a ball mill, a two or three roll mill, and the like. Among these, a flushing treatment, a kneading method using two or three roll mills, and a bead mill is suitable for fine particle formation.

  The flushing treatment is usually a method of mixing an organic pigment aqueous dispersion and a resin solution dissolved in a solvent immiscible with water, extracting the organic pigment from the aqueous medium into the organic medium, and treating the organic pigment with the resin. . According to this method, since the organic pigment is not dried, aggregation can be prevented and dispersion is facilitated. In kneading with a two or three roll mill, the organic pigment and resin or resin solution are mixed, and then the organic pigment and resin are kneaded while applying high shear (shearing force) to coat the resin on the surface of the organic pigment. In this way, the organic pigment is treated. The organic pigment particles aggregated in this process are dispersed from lower order aggregates to primary particles. The bead mill inserts a stirring shaft (rotating shaft) in which a plurality of disks are attached to an elongated vessel, and stirs the beads in the vessel at high speed. The agglomerated pigment in the pumped mill base is dispersed by the strong shear stress generated between the beads moving at high speed and when the beads collide with the inner wall shaft of the vessel.

In addition, processed organic pigments previously treated with an acrylic resin, vinyl chloride-vinyl acetate resin, maleic acid resin, ethyl cellulose resin, nitrocellulose resin or the like can also be used conveniently. As the form of the processed organic pigment treated with the above-mentioned various resins, powder, paste, pellet, and paste in which the resin and the organic pigment are uniformly dispersed are preferable. On the other hand, a non-uniform lump in which the resin is gelled is not preferable.

  In order to obtain an organic pigment dispersion having a fine particle size distribution, the organic pigment is first flashed or kneaded with a binder resin by a kneader, an extruder, a bead mill, two or three roll mills. As a preferable kneading method, wet dispersion (primary dispersion) is performed by mixing with other components including an organic pigment and a pigment dispersant. The obtained dispersion is subjected to wet dispersion (secondary dispersion) again using finer beads until the desired particle size distribution is obtained. Alternatively, the wet-dispersed dispersion is separated by centrifugation or coarse particles are removed by decantation to obtain particles having a desired particle size and size distribution.

  Moreover, a conventionally well-known pigment dispersant and surfactant can be added in order to improve the dispersibility of an organic pigment. As these dispersants, many types of compounds are used. For example, phthalocyanine derivatives (commercially available product EFKA-745 (manufactured by Morishita Sangyo)); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), (meth) acrylic acid (Co) polymer polyflow No. 75, no. 90, no. Cationic surfactants such as 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.) and W001 (manufactured by Yusho); polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenyl ether, polyoxy Nonionic surfactants such as ethylene nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, sorbitan fatty acid ester; F-top EF301, EF303, EF352 (manufactured by Shin-Akita Kasei), MegaFuck F171, F172, F173 (Dainippon) Ink), Fluorad FC430, FC431 (Sumitomo 3M), Asahi Guard AG710, Surflon S382, SC-101, SC-102, SC-103, SC-10 , SC-105, SC-1068 (manufactured by Asahi Glass), etc .; W004, W005, W017 (manufactured by Yusho) and other anionic surfactants; EFKA-46, EFKA-47, EFKA-47EA, Polymer dispersions such as EFKA polymer 100, EFKA polymer 400, EFKA polymer 401, EFKA polymer 450 (manufactured by Morishita Sangyo), disperse aid 6, disperse aid 8, disperse aid 15, disperse aid 9100 (manufactured by San Nopco) Agents: Solsperse 3000, 5000, 9000, 12000, 13240, 13940, 17000, 24000, 26000, 28000 and other Solsperse dispersants (manufactured by ICI); Adeka Pluronic L31, F38, L42, L44, L61, L64, F68, 72, P95, F77, P84, F87, P94, L101, P103, F108, L121, P-123 (manufactured by Asahi Denka) and Isonetto S-20 (manufactured by Sanyo Chemical Industries, Ltd.) and the like.

  Next, a preferred mode of use of the discolorant dispersion thus obtained will be described. The average particle size (average size) of the color changing agent is very important. When the average particle size is large, undesired light scattering occurs. As a result, when used in a light-sensitive material, the transmittance is reduced, and light necessary for image formation cannot be given to the inside of the image recording layer. End up. On the other hand, if the particle size is too small, the surface area of the color changing agent increases, and the effect of increasing the interaction with the developer due to melting during exposure is diminished. Furthermore, the dispersion stability tends to be insufficient, and undesirable problems such as aggregation and sedimentation occur in the discolored layer. From these viewpoints, the disperser dispersion of the present invention preferably has an average particle size of 0.5 μm or less, more preferably 0.02 to 0.3 μm, and still more preferably 0.05 to 0.2 μm. is there. Moreover, it is desirable that the volume fraction of particles larger than 0.5 μm is 10% or less.

As a method for incorporating the developer in the color-changing layer, a method in which the developer is dissolved and applied in an appropriate solvent is generally used, but this developer is applied in the same manner as the color-changing agent by the above-described dispersion method. The developer may be dispersed and applied, or the developer may be encapsulated in microcapsules or microgels and contained in the color changing layer. Microencapsulation or microgelation can be performed by a known method as described later.

  The color changing layer of the present invention is preferably formed by applying a coating solution containing a color developer and dispersing the color changing agent in the form of particles as described above, and then drying under the condition that the color changing agent particles do not melt. In addition, when a layer such as a protective layer is further provided on the color-changing layer, the drying is preferably performed under the condition that the color-changing agent particles do not melt.

The addition amount of the color changing agent per unit area of the lithographic printing plate precursor is set to an upper limit so as not to deteriorate the printing performance such as image forming property of the image recording layer, unexposed area on-machine developability, and exposed area charging property. On the other hand, the lower limit is set so that a sufficient effect for improving the plate inspection property can be obtained. These depend on the optical properties of the individual color changer. Preferably 0.001 to 1 g / m ^2, more preferably 0.005 to 0.5 / m ^2, and most preferably from 0.01 to 0.3 g / m ^2.
The addition amount of the developer per unit area of the lithographic printing plate precursor is preferably 0.001 to 1 g / m ² , more preferably 0.005 to 0.5 g / m ² , and most preferably 0.01 to 0.3 g / m ² .

  In addition to the color change agent and the color developer, a binder polymer, a surfactant, and other additives can be used as appropriate for the color change layer. Any binder polymer, surfactant, or other additive may be used as long as it can be used in an image recording layer, a protective layer, and an undercoat layer described later.

(Image recording layer)

(Infrared absorber)
In the image recording layer of the present invention, an infrared absorber is used in order to increase sensitivity to the infrared laser. The infrared absorber has a function of converting absorbed infrared rays into heat. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.

  Examples of preferable dyes include cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-60-78787, JP-A-58-173696, Methine dyes described in JP-A Nos. 58-181690 and 58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A Naphthoquinone dyes described in JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, etc., British Patent No. And cyanine dyes described in the specification of 434,875.

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

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and one particularly preferred example is a cyanine dye represented by the following general formula (I).

In the general formula (I), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below.

Here, Xa ^- is Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.
X ² represents an oxygen atom, a nitrogen 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.

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 (I) has an anionic substituent in its 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 (I) that can be suitably used in the present invention include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. be able to.
Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057 described above.

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

Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

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

  The particle diameter of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability of the pigment dispersion in the image recording layer coating solution and good uniformity of the image recording layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

These infrared absorbers may be added to the same layer as other components, may be added to the discoloration layer, or may be added to another layer. Further, it can be added by being encapsulated in microcapsules or microgels.
As the addition amount, when a negative lithographic printing plate precursor is prepared, the absorbance at the maximum absorption wavelength in the wavelength range of 760 nm to 1200 nm of the image recording layer is in the range of 0.3 to 1.2 by the reflection measurement method. It is preferable to add such that it is in a range of 0.4 to 1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the image recording layer, and good film strength of the image area and adhesion to the support can be obtained.
The absorbance of the image recording layer can be adjusted by the amount of infrared absorber added to the image recording layer and the thickness of the image recording layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image recording layer having a thickness appropriately determined in a range in which the coating amount after drying is necessary as a lithographic printing plate is formed, and the reflection density is set to the optical density. And a method of measuring with a spectrophotometer by a reflection method using an integrating sphere.

(Elements for forming printed images)
As elements that can be preferably used for forming a printed image in the image recording layer of the present invention, (A) an image forming element using polymerization, and (B) thermal fusion or thermal reaction of a hydrophobized precursor are used. Any imaging element can be used. Hereinafter, these elements will be described.

(A) Image forming element utilizing polymerization In an image forming element utilizing polymerization, the image recording layer of the present invention contains a polymerizable compound and a polymerization initiator.
Since the polymerization system element has high image formation sensitivity, the exposure energy can be effectively distributed to the printout image formation, and it is more preferable to obtain a printout image having a large brightness difference.

<Polymerizable compound>
The image recording layer of the present invention preferably contains a polymerizable compound in order to perform an efficient curing reaction. The polymerizable compound that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one ethylenically unsaturated bond, preferably two or more. It is. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer, isocyanuric acid There are EO-modified triacrylate and the like.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59-5241, and JP-A-2-226149. Those having the aromatic skeleton described above and those having an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

  In addition, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (a) to a polyisocyanate compound having two or more isocyanate groups. Compounds and the like.

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

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, It is possible to obtain a photopolymerizable composition having a very high photosensitive speed.

Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-B-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. Further, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337 and JP-B-1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also be mentioned. . In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300-308 (19
84)) that are introduced as photocurable monomers and oligomers can also be used.

About these addition polymerizable compounds, the details of usage, such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. Further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
Further, the selection and use method of the addition polymerization compound is also an important factor for the compatibility and dispersibility with other components (for example, binder polymer, initiator, colorant, etc.) in the image recording layer. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesion of the substrate and an overcoat layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass with respect to the nonvolatile component in the image recording layer. These may be used alone or in combination of two or more. In addition, the use method of the addition polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging property, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration and coating method such as undercoating and overcoating can be performed.

<Polymerization initiator>
The polymerization initiator used in the present invention is a compound that generates radicals by light, heat, or both, and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. Examples of the polymerization initiator that can be used in the present invention include known thermal polymerization initiators, compounds having a bond with small bond dissociation energy, and photopolymerization initiators. Among these, the polymerization initiator suitably used in the present invention is a compound that generates radicals by thermal energy. Hereinafter, the polymerization initiator used in the present invention will be described more specifically. Such polymerization initiators can be used alone or in combination of two or more.

  Examples of such polymerization initiators include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, Onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. Examples thereof include compounds described in Hutt, “Journal of Heterocyclic Chemistry”, 1 (No. 3), (1970). Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

More preferably, an s-triazine derivative having at least one mono, di, or trihalogen-substituted methyl group bonded to the s-triazine ring, specifically, for example, 2,4,6-tris (monochloromethyl)- s-triazine, 2,4,6-tris (dichloromethyl) -s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methyl-4,6-bis (trichloromethyl)- s-triazine, 2-n-propyl-4,6-bis (trichloromethyl) -s-triazine, 2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- [ 1- (p-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, 2- (P-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- ( p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-natoxynaphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2-Fe Ruthio-4,6-bis (trichloromethyl) -s-triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2,4,6-tris (dibromomethyl) -s-triazine, 2,4,6-tris (tribromomethyl) -s-triazine, 2-methyl-4,6-bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -S-triazine and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenyl) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p- Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

Examples of the organic peroxide include trimethylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butyl). Peroxy) cyclohexane, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tert-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2, -Oxanoyl peroxide, succinic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate , Dimethoxyisopropyl peroxycarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyacetate, tert-butyl peroxypivalate, tert-butyl peroxyneodecanoate, tert- Butyl peroxyoctanoate, tert-butyl peroxylaurate, tersyl carbonate, 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone, 3,3 ′, 4,4 ′ − Tra- (t-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra- (p-isopropylcumylperoxycarbonyl) benzophenone, carbonyldi (t-butylperoxydihydrogen diphthalate), carbonyl And di (t-hexylperoxydihydrogen diphthalate).

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Various titanocene compounds described in JP-A-5-83588, such as di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4,6-trifluorophen-1-yl, di- -Cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,4,5,6-penta Fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4,6-trifluoropheny -1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4 , 5,6-pentafluorophen-1-yl, iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109, and the like.

  Examples of the hexaarylbiimidazole compound include those described in Japanese Patent Publication No. 6-29285, US Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. Etc., specifically 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-bromo) Phenyl)) 4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2 '-Bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5 5'-tetraphenylbiimidazole, 2,2 '-Bis (o-nitrophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenyl Examples include biimidazole and 2,2′-bis (o-trifluorophenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole.

Examples of the organic boron compounds include JP-A-62-143044, JP-A-62-1050242, JP-A-9-188585, JP-A-9-188686, JP-A-9-188710, JP-A-2000-. 131837, JP 2002-107916 A, JP 2764769 A, JP 2002-116539 A, and Kunz, Martin, “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”. Organoboron salts described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes described in JP-A-6-157563, JP-A-175554, JP-A-6-175 The organic boron iodonium complex described in Japanese Patent No. 553, the organic boron phosphonium complex described in Japanese Patent Laid-Open No. 9-188710, and Japanese Patent Laid-Open No. 6-34.
Examples thereof include organoboron transition metal coordination complexes such as 8011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527, and JP-A-7-292014.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2002-328465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. Compounds, compounds described in JP-A No. 2000-80068, specifically, compounds represented by the following structural formulas may be mentioned.

Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, U.S. Pat. Nos. 339,049, 410,201, The iodonium salts described in the publications of Kaihei 2-150848 and JP-A-2-296514, European Patents 370,693, 390,214, 233,567, 297,443, No. 297,442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,0 No. 3, No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 A sulfonium salt described in each specification; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et a
l, J. et al. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

  Particularly preferred from the standpoint of reactivity and stability are the oxime ester compounds or onium salts (diazonium salts, iodonium salts or sulfonium salts).

  The onium salts preferably used in the present invention are onium salts represented by the following general formulas (RI-I) to (RI-III).

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

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

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group or alkyl group, alkyl group, alkenyl group or alkynyl group having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 1 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 1 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 1 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, and sulfate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.
Specific examples of the compounds represented by the above formulas (RI-I) to (RI-III) are shown below, but the present invention is not limited thereto.

  These polymerization initiators are preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 1 to 20% by mass with respect to the total solid content constituting the image recording layer. Can be added. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained. These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<Other image recording layer components>
The polymerization image recording layer of the present invention further contains additives such as a binder polymer, a surfactant, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, inorganic fine particles, and a low molecular weight hydrophilic compound as necessary. Can be made. These will be described below.

<Binder polymer>
The image recording layer of the present invention can contain a binder polymer. As the binder polymer that can be used in the present invention, conventionally known binder polymers can be used without limitation, and a linear organic polymer having a film property is preferable. Examples of such binder polymers include acrylic resins, polyvinyl acetal resins, polyurethane resins, polyurea resins, polyimide resins, polyamide resins, epoxy resins, methacrylic resins, polystyrene resins, novolac phenolic resins, polyester resins, and synthetic rubbers. And natural rubber.

The binder polymer preferably has crosslinkability in order to improve the film strength of the image area. In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization.

Examples of the polymer having an ethylenically unsaturated bond in the main chain of the molecule include poly-1,4-butadiene and poly-1,4-isoprene.
Examples of polymers having an ethylenically unsaturated bond in the side chain of the molecule are polymers of esters or amides of acrylic acid or methacrylic acid where the ester or amide residue (R of -COOR or -CONHR) is Mention may be made of polymers having an ethylenically unsaturated bond.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, - (CH 2) n CR} 1 = CR 2 R 3, - (CH 2 O) n CH 2 CR 1 = CR 2 R 3, - _{(CH 2 CH 2 O) n} CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 = CR 2 R 3, - (CH 2) n -O-CO —CR ¹ ═CR ² R ³ and — (CH ₂ CH ₂ O) ₂ —X (wherein R ^{1 to} R ³ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may combine with each other to form a ring, n represents an integer of 1 to 10. X represents dicyclopentadienyl. Represents a residue).

Specific examples of the ester _{residue, -CH 2 CH = CH 2,} ( described in JP Kokoku _{7-21633.) - CH 2 CH 2} O-CH 2 CH = CH 2, -CH 2 C _{(CH 3) = CH 2,} -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, -CH 2 CH 2 -NHCOO-CH 2 CH = CH 2 and - CH ₂ CH ₂ O—X (wherein X represents a dicyclopentadienyl residue).
Specific examples of the amide residue include —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ —Y (wherein Y represents a cyclohexene residue), —CH ₂ CH ₂ —OCO—CH═CH _2. Is mentioned.

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

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond polymerizable by iodometric titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0 to 1 g per 1 g of the binder polymer. 7.0 mmol, most preferably 2.0-5.5 mmol. Within this range, good sensitivity and good storage stability can be obtained.

From the viewpoint of improving on-press developability, the binder polymer preferably has high solubility or dispersibility in ink and / or fountain solution.
In order to improve the solubility or dispersibility in ink, the binder polymer is preferably lipophilic, and in order to improve the solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. For this reason, in the present invention, it is also effective to use a lipophilic binder polymer and a hydrophilic binder polymer in combination.

Examples of hydrophilic binder polymers include hydroxy groups, carboxyl groups, carboxylate groups, hydroxyethyl groups, polyoxyethyl groups, hydroxypropyl groups, polyoxypropyl groups, amino groups, aminoethyl groups, aminopropyl groups, and ammonium. Group,
Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

  The binder polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. More preferred. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

  The binder polymer may be any of a random polymer, a block polymer, and a graft polymer, but a random polymer is more preferable. Moreover, a binder polymer may be used independently or may be used in mixture of 2 or more types.

The binder polymer can be synthesized by a conventionally known method. Solvents used in the synthesis include, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy. Examples include 2-propanol, 1-methoxy-2-propyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate, dimethyl sulfoxide, and water. These may be used alone or in combination of two or more.
As the polymerization initiator used when synthesizing the binder polymer, known compounds such as an azo initiator and a peroxide initiator can be used.

The content of the binder polymer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and preferably 30 to 70% by mass with respect to the total solid content of the image recording layer. Further preferred. Within this range, good image area strength and image formability can be obtained.
Moreover, it is preferable to use a polymeric compound and a binder polymer in the quantity used as 1 / 9-7 / 3 by mass ratio.

<Surfactant>
In the present invention, it is preferable to use a surfactant in the image recording layer in order to promote on-press developability at the start of printing and to improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohols Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorine-type surfactant described in each gazette of Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the image recording layer.

<Polymerization inhibitor>
In order to prevent unnecessary thermal polymerization of the polymerizable compound (C) during the production or storage of the image recording layer, a small amount of a thermal polymerization inhibitor is preferably added to the image recording layer of the present invention.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the image recording layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the image recording layer of the present invention, and the surface of the image recording layer is dried during the coating process. It may be unevenly distributed. The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image recording layer.

<Plasticizer>
The image recording layer of the present invention may contain a plasticizer in order to improve the on-press developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the image recording layer.

<Inorganic fine particles>
The image recording layer of the present invention may contain inorganic fine particles for the purpose of improving the strength of the cured film in the image area and improving the on-press developability of the non-image area.
As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion having excellent hydrophilicity, which is stably dispersed in the image recording layer, sufficiently retains the film strength of the image recording layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the image recording layer.

<Low molecular hydrophilic compound>
The image recording layer of the present invention may contain a hydrophilic low molecular weight compound for improving on-press developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Examples thereof include organic carboxylic acids such as salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, and amino acids, and salts thereof.

<Formation of polymerization-type image recording layer>
In the present invention, several modes can be used as a method for incorporating the image recording layer constituting component into the image recording layer. One is a molecular dispersion type image recording layer in which the constituent components are dissolved and applied in an appropriate solvent as described in, for example, JP-A-2002-287334. In another embodiment, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or a part of the constituent components are encapsulated in microcapsules and contained in the image recording layer. It is a microcapsule type image recording layer. Further, in the microcapsule type image recording layer, the constituent component can be contained outside the microcapsule. Here, it is preferable that the microcapsule-type image recording layer includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule. As still another embodiment, an embodiment in which the image recording layer contains crosslinked resin particles, that is, microgel, can be mentioned. The microgel may contain a part of the constituent component in and / or on the surface thereof. In particular, an embodiment in which a reactive microgel is formed by having a polymerizable compound on the surface thereof is particularly preferable from the viewpoint of image formation sensitivity and printing durability.
In order to obtain better on-press developability, the image recording layer is preferably a microcapsule type or microgel type image recording layer.

  As a method for microencapsulating or microgelling the components of the image recording layer, known methods can be applied.

For example, as a method for producing microcapsules, US Pat. No. 2,800,547, US Pat. No. 2,800,498, a method using coacervation, US Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, A method based on an interfacial polymerization method found in US Pat. No. 42-446, a method based on precipitation of a polymer found in US Pat. Nos. 3,418,250 and 3,660,304, an isocyanate found in US Pat. No. 3,796,669. Method using polyol wall material, method using isocyanate wall material found in US Pat. No. 3,914,511, urea found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802 -Formaldehyde or urea formaldehyde -A method using a resorcinol-based wall forming material, a method using a wall material such as melamine-formaldehyde resin, hydroxycellulose, etc. found in US Pat. No. 4,025,445, Japanese Patent Publication Nos. 36-9163 and 51-9079. In-situ method by monomer polymerization, British Patent No. 930422, US Pat. No. 3,111,407 Spray drying method, British Patent No. 952807, US Pat. No. 9,670,741 Although there is a cooling method, it is not limited to these.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Further, a compound having a crosslinkable functional group such as an ethylenically unsaturated bond capable of introducing a binder polymer may be introduced into the microcapsule wall.

On the other hand, as a method for preparing the microgel, granulation by interfacial polymerization described in JP-B-38-19574 and JP-A-42-446, non-patent document as described in JP-A-5-61214, and the like. Granulation by aqueous dispersion polymerization can be used. However, it is not limited to these methods.
As the method using the interfacial polymerization, the known microcapsule production method described above can be applied.

  Preferred microgels used in the present invention are those granulated by interfacial polymerization and having three-dimensional crosslinking. From such a viewpoint, the material to be used is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and polyurea and polyurethane are particularly preferable.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

The image recording layer of the present invention is applied by preparing a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, water and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The image recording layer of the present invention can also be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but generally 0.3 to 3.0 g / m ² is preferable. Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

(B) Hydrophobized precursor image forming element <hydrophobized precursor>
In the present invention, the hydrophobized precursor is a fine particle capable of converting a hydrophilic image recording layer to hydrophobic when heat is applied. The fine particles are preferably at least one fine particle selected from thermoplastic polymer fine particles and heat-reactive polymer fine particles. Moreover, the microcapsule or microgel which included the compound which has a thermoreactive group may be sufficient.

  As the thermoplastic polymer fine particles used in the image recording layer of the present invention, Research Disclosure No. 33303 of January 1992, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, Preferred examples include thermoplastic polymer fine particles described in 9-171250 and European Patent No. 931647. Specific examples of the polymer constituting the polymer fine particle include homopolymers of monomers such as ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, or the like. Mention may be made of copolymers or mixtures thereof. Among them, more preferred are polystyrene and polymethyl methacrylate.

  The average particle size of the thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. As a method for synthesizing such thermoplastic polymer fine particles, in addition to emulsion polymerization and suspension polymerization, these compounds are dissolved in a water-insoluble organic solvent, and this is mixed and emulsified with an aqueous solution containing a dispersant. Further, there is a method (solution dispersion method) in which heat is further applied to solidify into fine particles while the organic solvent is being blown away.

  Examples of the heat-reactive polymer fine particles used in the present invention include thermosetting polymer fine particles and polymer fine particles having a heat-reactive group.

  Examples of the thermosetting polymer include a resin having a phenol skeleton, a urea resin (for example, urea or a derivatized urea derivative such as methoxymethylated urea with an aldehyde such as formaldehyde), a melamine resin (for example, melamine or Examples thereof include those obtained by converting the derivatives into resins with aldehydes such as formaldehyde, alkyd resins, unsaturated polyester resins, polyurethane resins, and epoxy resins. Among these, resins having a phenol skeleton, melamine resins, urea resins and epoxy resins are particularly preferable.

  Suitable resins having a phenol skeleton include, for example, phenol resins obtained by converting phenol, cresol and the like with aldehydes such as formaldehyde, hydroxystyrene resins, N- (p-hydroxyphenyl) methacrylamide, and p-hydroxyphenyl methacrylate. Examples thereof include a polymer or copolymer of methacrylamide or acrylamide or methacrylate or acrylate having a phenol skeleton.

  The average particle diameter of the thermosetting polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm. Such thermosetting polymer fine particles can be easily obtained by a solution dispersion method, but may be formed into fine particles when the thermosetting polymer is synthesized. However, it is not restricted to these methods.

The thermally reactive group of the polymer fine particle having a thermally reactive group used in the present invention may be any functional group that performs a reaction as long as a chemical bond is formed, but is an ethylenically unsaturated group that performs a radical polymerization reaction. Group (for example, acryloyl group, methacryloyl group, vinyl group, allyl group, etc.), cationic polymerizable group (for example, vinyl group, vinyloxy group, etc.), isocyanate group that performs addition reaction or its block, epoxy group, vinyloxy group And a functional group having an active hydrogen atom as a reaction partner thereof (for example, an amino group, a hydroxyl group, a carboxyl group, etc.), a carboxyl group for performing a condensation reaction, a hydroxyl group or an amino group as a reaction partner, a ring-opening addition reaction Suitable acid anhydride and reaction partner amino group or hydroxyl group It can gel.

  The introduction of these functional groups into the polymer fine particles may be performed at the time of polymerization, or may be performed using a polymer reaction after the polymerization.

  When introduced at the time of polymerization, the monomer having the above functional group is preferably subjected to emulsion polymerization or suspension polymerization. Specific examples of the monomer having the above functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, 2- (vinyloxy) ethyl methacrylate, p-vinyloxystyrene, p- {2- (vinyloxy) ethyl} styrene, Block isocyanate with glycidyl methacrylate, glycidyl acrylate, 2-isocyanatoethyl methacrylate or alcohol thereof, block isocyanate with 2-isocyanate ethyl acrylate or alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, Such as functional methacrylates include, but are not limited to.

  In the present invention, a copolymer of these monomers and a monomer that is copolymerizable with these monomers and does not have a thermally reactive group can also be used. Examples of the copolymer monomer having no heat-reactive group include styrene, alkyl acrylate, alkyl methacrylate, acrylonitrile, vinyl acetate, and the like. It is not limited to.

  Examples of the polymer reaction used when the introduction of the thermally reactive group is carried out after the polymerization include the polymer reaction described in International Publication No. 96/34316 pamphlet.

  Among the polymer fine particles having a heat-reactive group, those in which the polymer fine particles are coalesced by heat are preferable, and those having a hydrophilic surface and being dispersed in water are particularly preferable. The contact angle (water droplets) of the film prepared by applying only polymer fine particles and drying at a temperature lower than the solidification temperature is higher than the contact angle (water droplets) of the film prepared by drying at a temperature higher than the solidification temperature. It is preferable to lower. In order to make the surface of the polymer fine particles hydrophilic in this way, a hydrophilic polymer or oligomer such as polyvinyl alcohol or polyethylene glycol or a hydrophilic low molecular weight compound may be adsorbed on the surface of the polymer fine particles. However, the surface hydrophilization method is not limited to this.

  The solidification temperature of the polymer fine particles having these thermoreactive groups is preferably 70 ° C. or higher, but more preferably 100 ° C. or higher in view of the stability over time. The average particle size of the polymer fine particles is preferably 0.01 to 2.0 μm, more preferably 0.05 to 2.0 μm, and most preferably 0.1 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  As the heat-reactive group in the microcapsule or microgel encapsulating the compound having a heat-reactive group used in the present invention, the same heat-reactive group as that used for the polymer fine particles having the heat-reactive group is preferable. Can be cited as a thing. Below, the compound which has a thermoreactive group is demonstrated.

  As the compound having a polymerizable unsaturated group, the same compounds as shown in the above-mentioned polymerization type microcapsules or microgels are preferably used.

  Examples of the compound having a vinyloxy group suitable for the present invention include compounds described in JP-A-2002-29162. Specific examples include tetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, 1,4-bis {2- (vinyloxy) ethyloxy} Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3,5-tris {2- (vinyloxy) ethyloxy} benzene, 4 , 4′-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4′-bis {2- (vinyloxy) ester Ruoxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5-bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, , 5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane {bis (vinyloxyethyl) ether of bisphenol A}, 2,2- Examples include, but are not limited to, bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane, and the like.

  As the compound having an epoxy group suitable for the present invention, a compound having two or more epoxy groups is preferable, and a glycidyl ether compound or a prepolymer thereof obtained by reaction of a polyhydric alcohol, a polyhydric phenol or the like with epichlorohydrin. Furthermore, a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate can be used.

  Specific examples include propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of hydrogenated bisphenol A, hydroquinone diglycidyl. Ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether or epichlorohydride of halogenated bisphenol A Phosphorus polyadduct, diglycidyl ether of biphenyl type bisphenol or epichlorohydrin polyadduct, Novo Click glycidyl ethers such as a resin, further, methyl methacrylate / glycidyl methacrylate copolymer, methacrylic acid ethyl / glycidyl methacrylate copolymer, and the like.

  Commercially available products of the above compounds include, for example, Epicoat 1001 (molecular weight: about 900, epoxy equivalent: 450 to 500), Epicoat 1002 (molecular weight: about 1600, epoxy equivalent: 600 to 700), Epicoat 1004 (about) manufactured by Japan Epoxy Resin Co., Ltd. 1060, epoxy equivalent 875-975), Epicoat 1007 (molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009 (molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010 (molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100L (epoxy equivalent) 4000), Epicoat YX31575 (epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195XL, ESCN-195XF, and the like.

Suitable isocyanate compounds for the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diisocyanate, Examples include hexamethylene diisocyanate, cyclohexyl diisocyanate, and compounds obtained by blocking these with alcohol or amine.

  Suitable amine compounds for the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.

  Examples of the compound having a hydroxyl group suitable for the present invention include a compound having a terminal methylol group, a polyhydric alcohol such as pentaerythritol, and bisphenol / polyphenols.

  Examples of the compound having a carboxyl group suitable for the present invention include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid. Examples of the acid anhydride suitable for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  Microencapsulation or microgelation of the above-mentioned compound having a thermoreactive group can be performed by the known method described above in the description of the polymerization system.

<Other image recording layer components>
The image recording layer of the present invention may contain a hydrophilic resin for improving on-press developability and improving the film strength of the image recording layer itself. As hydrophilic resin, what has hydrophilic groups, such as a hydroxyl group, an amino group, a carboxyl group, a phosphoric acid group, a sulfonic acid group, an amide group, is preferable, for example. The hydrophilic resin preferably has a group that reacts with the heat-reactive group because it reacts with the heat-reactive group of the hydrophobizing precursor and crosslinks to increase the image strength. . For example, when the hydrophobizing precursor has a vinyloxy group or an epoxy group, the hydrophilic resin preferably has a hydroxyl group, a carboxyl group, a phosphoric acid group, a sulfonic acid group, or the like. Among these, a hydrophilic resin having a hydroxyl group or a carboxyl group is preferable.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, soya gum, hydroxypropylcellulose, methylcellulose, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-malein Acid copolymers, polyacrylic acids and salts thereof, polymethacrylic acids and salts thereof, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate Homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers , Homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate having a degree of hydrolysis of at least 60 mol%, preferably at least 80 mol%, polyvinyl formal, polyvinyl pyrrolidone Homopolymers and copolymers of acrylamide, homopolymers and copolymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, homopolymers and copolymers of 2-acrylamido-2-methyl-1-propanesulfonic acid, 2-methacryloyloxy Mention may be made of homopolymers and copolymers of ethylphosphonic acid.

  The amount of the hydrophilic resin added to the image recording layer is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Further, the hydrophilic resin may be used after being cross-linked to such an extent that an unexposed portion can be developed on-press on a printing press. Cross-linking agents include glyoxal, aldehydes such as melamine formaldehyde resin, urea formaldehyde resin, methylol compounds such as N-methylol urea, N-methylol melamine, and methylolated polyamide resin, divinyl sulfone and bis (β-hydroxyethylsulfonic acid) Active vinyl compounds such as, epoxy compounds such as epichlorohydrin and polyethylene glycol diglycidyl ether, polyamides, polyamines, epichlorohydrin adducts, polyamide epichlorohydrin resins, ester compounds such as monochloroacetic acid esters and thioglycolic acid esters, Polycarboxylic acids such as polyacrylic acid and methyl vinyl ether / maleic acid copolymer, inorganic such as boric acid, titanyl sulfate, Cu, Al, Sn, V, Cr salts Crosslinking agents, such as modified polyamide polyimide resin. In addition, a crosslinking catalyst such as ammonium chloride, a silane coupling agent, a titanate coupling agent, or the like can be used in combination.

  The image recording layer of the present invention may contain a reaction accelerator that initiates or accelerates the reaction of the thermally reactive group. Preferred examples of the reaction accelerator include the above-mentioned photoacid generator or radical generator in the color changing system and the polymerization initiator in the polymerization system.

  Two or more kinds of the reaction accelerators can be used in combination. Further, the reaction accelerator may be added directly to the image recording layer coating solution or may be added in the form of polymer fine particles. The content of the reaction accelerator in the image recording layer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total solid content of the image recording layer. Within this range, good reaction initiation or acceleration effect can be obtained without impairing on-press developability.

  In order to further improve the printing durability, a polyfunctional monomer can be added to the image recording layer matrix in the image recording layer of the hydrophobized precursor system of the present invention. As this polyfunctional monomer, those exemplified as the polymerizable compound can be used. Among them, preferable monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like.

  The image recording layer of the hydrophobized precursor system of the present invention includes a surfactant, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, an inorganic material described in <Other image recording layer components> of the polymerization image recording layer. Additives such as fine particles and low molecular weight hydrophilic compounds can be contained as required.

<Formation of image recording layer of hydrophobized precursor system>
As in the case of the polymerization-type image recording layer, the image recording layer of the hydrophobized precursor system of the present invention is prepared by coating or drying on a support by preparing a coating solution in which each of the above-described components is dispersed or dissolved in a solvent. Formed.

The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but is generally preferably 0.5 to 5.0 g / m ² .

By using the image recording layer of the hydrophobized precursor system, a lithographic printing plate precursor capable of on-press development can be produced.
On the other hand, the lithographic printing plate precursor of the present invention is not treated (no development) by making the image recording layer of the hydrophobized precursor system a “hydrophilic layer having a crosslinked structure” having sufficient printing durability even when unexposed. It can be applied to the lithographic printing plate precursor of the mold.

  The hydrophilic layer having such a crosslinked structure preferably includes at least one of a hydrophilic resin formed with a crosslinked structure and an inorganic hydrophilic binder resin formed by sol-gel conversion. It is. Of these, the hydrophilic resin will be described first. By adding this hydrophilic resin, there is an advantage that the affinity with the hydrophilic component in the emulsion ink is improved and the film strength of the image recording layer itself is improved. As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl, carboxymethyl and the like are preferable.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and Salts thereof, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, hydroxybutyl Homopolymers and copolymers of methacrylate, homopolymers and copolymers of hydroxybutyl acrylate Homopolymers of limers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide having a degree of hydrolysis of at least 60 mol%, preferably at least 80 mol% And copolymers, methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.

  When the hydrophilic resin is used in the image recording layer according to the present invention, the hydrophilic resin may be used after being crosslinked. As the crosslinking agent used for forming the crosslinked structure, those mentioned as the crosslinking agent are used.

  Further, as a preferred embodiment of the non-processing (non-development) type image recording layer, there can be mentioned those containing an inorganic hydrophilic binder resin formed by sol-gel conversion. A preferred sol-gel conversion binder resin is that a bonding group coming out of a polyvalent element forms a network structure, that is, a three-dimensional cross-linked structure via an oxygen atom, and at the same time, the polyvalent metal is an unbonded hydroxyl group. And a polymer having a resinous structure in which these are mixed, and is in a sol state at a stage where there are many alkoxy groups and hydroxyl groups, and has a network shape as dehydration condensation proceeds. The resin structure becomes strong. Examples of the polyvalent bonding element of the compound having a hydroxyl group or an alkoxy group that performs sol-gel conversion include aluminum, silicon, titanium, and zirconium, and any of these can be used in the present invention. Among these, a sol-gel conversion system using silicon is more preferable, and a system including a silane compound having at least one silanol group capable of sol-gel conversion is particularly preferable. Hereinafter, a sol-gel conversion system using silicon will be described. However, a sol-gel conversion system using aluminum, titanium, and zirconium can be implemented by replacing silicon described below with each element.

  The sol-gel conversion binder resin is preferably a resin having a siloxane bond and a silanol group, and the image recording layer of the present invention includes a coating solution that is a sol system containing at least one compound having a silanol group. Used, it is contained by a process in which condensation of silanol groups proceeds and gels in the process of coating and drying to form a structure of a siloxane skeleton.

In addition, the image recording layer containing the sol-gel conversion binder resin is used in combination with the hydrophilic resin and the crosslinking agent for the purpose of improving physical properties such as film strength and film flexibility and improving coating properties. It is also possible to do.

  The siloxane resin forming the gel structure is represented by the following general formula (II), and the silane compound having at least one silanol group is represented by the following general formula (III). In addition, the substance system added to the image recording layer does not necessarily need to be a silane compound of the general formula (III) alone, and is generally an oligomer in which a silane compound is partially condensed or a silane compound and an oligomer of the general formula (III). There may be a mixture of.

The siloxane resin represented by the general formula (II) is formed by sol-gel conversion from a dispersion containing at least one silane compound represented by the general formula (III). Here, at least one of R ^{01 to} R ⁰³ in the general formula (II) represents a hydroxyl group, and the other represents an organic residue selected from the symbols R ⁰ and Y in the general formula (III).

Formula (III) (R ⁰ ) _n Si (Y) _4-n

Here, R ⁰ represents a hydroxyl group, a hydrocarbon group or a heterocyclic group. Y represents a hydrogen atom, a halogen atom, —OR ¹ , —OCOR ² , or N (R ³ ) (R ⁴ ). R ¹ and R ² each represent a hydrocarbon group, and R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group or a hydrogen atom. n represents 0, 1, 2 or 3.

The hydrocarbon group or heterocyclic group for R ⁰ is, for example, a linear or branched alkyl group having 1 to 12 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group). Group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, etc .; these groups include halogen atoms (chlorine atom, fluorine atom, bromine atom), hydroxyl group, thiol group , Carboxyl group, sulfo group, cyano group, epoxy group, —OR ′ group (R ′ is methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, octyl group, decyl group, propenyl group, butenyl group) Group, hexenyl group, octenyl group, 2-hydroxyethyl group, 3-chloropropyl group, 2-cyanoethyl group, N, N-dimethylaminoethyl group, 2-bromo An ethyl group, 2- (2-methoxyethyl) oxyethyl group, 2-methoxycarbonylethyl group, 3-carboxyethyl group, 3-carboxypropyl group, benzyl group, etc.), -OCOR ″ group (R ″ is Represents the same content as R ′), —COOR ″ group, —COR ″ group, —N (R ′ ″) (R ″ ′) group (R ′ ″ represents a hydrogen atom or R ′ represents the same content as R ′ and may be the same or different from each other), —NHCONHR ″ group, —NHCOOR ″ group, —Si (R ″) ₃ group, —CONHR ″ group and the like. In the alkyl group, a plurality of substituents may be substituted in a linear or branched alkenyl group having 2 to 12 carbon atoms (for example, a vinyl group, a propenyl group, a butenyl group, a pentenyl group, Hexenyl, octenyl, decenyl, dodecenyl, etc .; these Examples of the group substituted with the above-mentioned groups include those having the same contents as the group substituted with the alkyl group, and an aralkyl group having 7 to 14 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3- A phenylpropyl group, a naphthylmethyl group, a 2-naphthylethyl group, etc .; examples of the group substituted by these include those having the same content as the group substituted by the alkyl group, and a plurality thereof may be substituted) An alicyclic group having 5 to 10 carbon atoms which may be substituted (for example, a cyclopentyl group, a cyclohexyl group, a 2-cyclohexylethyl group, a norbornyl group, an adamantyl group, etc .; And those having the same contents as the group to be substituted may be mentioned, or a plurality of them may be substituted), an aryl group having 6 to 12 carbon atoms (for example, phenyl) In the naphthyl group, the substituent may be the same as the group substituted with the alkyl group, or a plurality of substituents may be substituted), or selected from a nitrogen atom, an oxygen atom, and a sulfur atom. A heterocyclic group which may be condensed, containing at least one atom (for example, pyran ring, furan ring, thiophene ring, morpholine ring, pyrrole ring, thiazole ring, oxazole ring, pyridine ring, piperidine ring, pyrrolidone ring, A benzothiazole ring, a benzoxazole ring, a quinoline ring, a tetrahydrofuran ring and the like may contain a substituent. Examples of the substituent include those having the same content as the group substituted with the alkyl group, and a plurality of substituents may be substituted.

Examples of the substituent of the —OR ¹ group, —OCOR ² group or N (R ³ ) (R ⁴ ) group of Y in the general formula (III) represent the following substituents. In the —OR ¹ group, R ¹ is an optionally substituted aliphatic group having 1 to 10 carbon atoms [eg, methyl group, ethyl group, propyl group, butyl group, heptyl group, hexyl group, pentyl group, octyl group, Nonyl group, decyl group, propenyl group, butenyl group, heptenyl group, hexenyl group, octenyl group, decenyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 2-methoxyethyl group, 2- (2-methoxyethyl) Oxyethyl group, 2- (N, N-dimethylamino) ethyl group, 2-methoxypropyl group, 2-cyanoethyl group, 3-methyloxypropyl group, 2-chloroethyl group, cyclohexyl group, cyclopentyl group, cyclooctyl group, chloro Cyclohexyl, methoxycyclohexyl, benzyl, phenethyl, dimethoxybenzyl, methyl A rubenzyl group, a bromobenzyl group, and the like.

In the —OCOR ² group, R ² is an aliphatic group having the same contents as R ¹ or an aromatic group having 6 to 12 carbon atoms which may be substituted (the aromatic group is the same as that exemplified for the aryl group of R above) Are included). In the —N (R ³ ) (R ⁴ ) group, R ³ and R ⁴ may be the same or different from each other, and each is a hydrogen atom or an aliphatic group having 1 to 10 carbon atoms which may be substituted (for example, And those having the same contents as R ¹ of the —OR ¹ group. More preferably, the total number of carbon atoms of R ³ and R ⁴ is 16 or less. Specific examples of the silane compound represented by the general formula (III) include the following, but are not limited thereto.

Tetrachlorosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra n-propylsilane, methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrichlorosilane, ethyltrimethoxysilane, ethyltriethoxysilane , N-propyltrichlorosilane, n-propyltrimethoxysilane, n-hexyltrimethoxysilane, n-decyltrimethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, dimethoxyditriethoxysilane, dimethyldichlorosilane, dimethyldimethoxysilane , Diphenyldimethoxysilane, phenylmethyldimethoxysilane, triethoxyhydrosilane, trimethoxyhydrosilane, vinyltrichlorosilane, Nyltrimethoxysilane, trifluoropropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylpropyl Methoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, β- (3,4- (Epoxycyclohexyl) ethyltrimethoxysilane and the like.

In the image recording layer of the present invention, together with the silane compound of the general formula (III), a metal compound capable of forming a film by bonding to a resin during sol-gel conversion such as Ti, Zn, Sn, Zr, Al, etc. is used in combination. be able to. Examples of the metal compound used include Ti (OR ″) ₄ , TiCl ₄ , Zn (OR ″) ₂ , Zn (CH ₃ COCHCOCH ₃ ) ₂ , Sn (OR ″) ₄ , Sn (CH ₃ COCHCOCH ₃ ) ₄ , Sn (OCOR ″) ₄ , SnCl ₄ , Zr (OR ″) ₄ , Zr (CH ₃ COCHCOCH ₃ ) ₄ , (NH ₄ ) ₂ ZrO (CO ₃ ) ₂ , Al (OR ″) ₃ , Al (CH ₃ COCHCOCH ₃ ) _{3 and the} like. Here, R ″ represents a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group or the like.

  Further, in order to promote the hydrolysis and polycondensation reaction of the compound represented by the general formula (III) and the metal compound used in combination, it is preferable to use an acidic catalyst or a basic catalyst in combination. As the catalyst, an acid or a basic compound is used as it is or in a state in which it is dissolved in a solvent such as water or alcohol (hereinafter referred to as an acidic catalyst and a basic catalyst, respectively). The concentration at that time is not particularly limited, but when the concentration is high, the hydrolysis and polycondensation rates tend to increase. However, when a basic catalyst having a high concentration is used, a precipitate may be generated in the sol solution. Therefore, the concentration of the basic catalyst is preferably 1 N (concentration in aqueous solution) or less.

  Specific examples of the acidic catalyst include hydrohalic acid such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid, carboxylic acid such as formic acid and acetic acid, and sulfonic acid such as benzenesulfonic acid. Is mentioned. Specific examples of the basic catalyst include, but are not limited to, an ammoniacal base such as aqueous ammonia and amines such as ethylamine and aniline.

  The image recording layer using the sol-gel method described above is particularly preferable as the configuration of the image recording layer according to the present invention. For further details on the sol-gel method, see Sakuo Sakuo, "Science of Sol-Gel Method", published by Agne Jofusha Co., Ltd. (1988), Satoshi Hirashima, "Functional Thin Film Preparation by Latest Sol-Gel Method" Technology ", published by the General Technology Center (1992).

  The amount of the hydrophilic resin added to the image recording layer having a crosslinked structure is preferably 5 to 70% by mass, more preferably 5 to 50% by mass based on the solid content of the image recording layer.

[Support]
The support used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. 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 preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or hydrophilic film formation. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion between the image recording layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

<Roughening treatment>
The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, 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.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

<Formation of hydrophilic film>
The method for providing the hydrophilic film is not particularly limited, and an anodic oxidation method, a vapor deposition method, a CVD method, a sol-gel method, a sputtering method, an ion plating method, a diffusion method, and the like can be appropriately used. Moreover, the method of apply | coating the solution which mixed the hollow particle in hydrophilic resin or sol-gel liquid can also be used.

Among these, it is most preferable to use an anodizing process, that is, an anodizing process. The anodizing treatment can be performed by a method conventionally used in this field. Specifically, when direct current or alternating current is applied to an aluminum plate in an aqueous solution or non-aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., alone or in combination of two or more. An anodized film that is a hydrophilic film can be formed on the surface of the aluminum plate. The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined unconditionally. In general, however, the electrolyte concentration is 1 to 80% by mass, the solution temperature is 5 to 70 ° C., and the current density is 0.5. ˜60 A / dm ² , voltage 1 to 200 V, electrolysis time 1 to 1000 seconds are appropriate. Among these anodizing treatments, a method for anodizing at a high current density in a sulfuric acid electrolyte solution described in British Patent No. 1,412,768, and US Pat. No. 3,511, A method of anodizing treatment using phosphoric acid as an electrolytic bath described in the specification of No. 661 is preferable. Further, multi-stage anodizing treatment such as anodizing treatment in sulfuric acid and further anodizing treatment in phosphoric acid can be performed.

In the present invention, the anodized film is preferably 0.1 g / m ² or more, more preferably 0.3 g / m ² or more, in terms of scratch resistance and printing durability. / M ² or more is particularly preferable, and 3.2 g / m ² or more is more preferable. In view of the fact that enormous energy is required to provide a thick film, it is preferably 100 g / m ² or less, more preferably 40 g / m ² or less, and 20 g / m ² or less. It is particularly preferred.

  On the surface of the anodized film, fine recesses called micropores are uniformly distributed. The density of the micropores present in the anodized film can be adjusted by appropriately selecting the treatment conditions. By increasing the density of the micropores, the thermal conductivity in the film thickness direction of the anodized film can be lowered. Further, the diameter of the micropores can be adjusted by appropriately selecting the processing conditions. By increasing the diameter of the micropore, the thermal conductivity in the film thickness direction of the anodized film can be lowered.

In the present invention, for the purpose of lowering the thermal conductivity, it is preferable to perform a pore wide treatment for expanding the pore diameter of the micropore after the anodizing treatment. In this pore wide treatment, the anodized film is dissolved by immersing the aluminum substrate on which the anodized film is formed in an acid aqueous solution or an alkali aqueous solution, and the pore diameter of the micropore is enlarged. In the pore wide treatment, the amount of dissolution of the anodized film is preferably 0.01 to 20 g / m ² , more preferably 0.1 to 5 g / m ² , and particularly preferably 0.2 to 4 g / m ^2. Done.

  When an aqueous acid solution is used for the pore wide treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the acid aqueous solution is preferably 10 to 1000 g / L, and more preferably 20 to 500 g / L. The temperature of the acid aqueous solution is preferably 10 to 90 ° C, and more preferably 30 to 70 ° C. The immersion time in the acid aqueous solution is preferably 1 to 300 seconds, and more preferably 2 to 100 seconds. On the other hand, when an alkaline aqueous solution is used for pore wide treatment, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The pH of the alkaline aqueous solution is preferably 10 to 13, and more preferably 11.5 to 13.0. The temperature of the aqueous alkali solution is preferably 10 to 90 ° C, and more preferably 30 to 50 ° C. The immersion time in the alkaline aqueous solution is preferably 1 to 500 seconds, and more preferably 2 to 100 seconds. However, if the micropore diameter on the outermost surface is enlarged too much, the stain performance at the time of printing deteriorates. Therefore, the micropore diameter on the outermost surface is preferably 40 nm or less, more preferably 20 nm or less. The following is most preferable. Therefore, both heat insulation and dirt performance are achieved. As a more preferable anodic oxide film shape, the surface micropore diameter is 0 to 40 nm and the internal micropore diameter is 20 to 300 nm. For example, it is known that if the type of the electrolytic solution is the same, the pore diameter of the pore generated by electrolysis is proportional to the electrolytic voltage during electrolysis. A method in which pores having an expanded bottom portion can be generated by gradually increasing the electrolysis voltage using this property can be used. Further, it is known that the pore diameter changes when the type of the electrolytic solution is changed, and the pore diameter increases in the order of sulfuric acid, oxalic acid, and phosphoric acid. Therefore, it is possible to use a method in which sulfuric acid is used as the electrolytic solution in the first stage and phosphoric acid is used in the second stage. Moreover, you may perform the below-mentioned sealing process to the support for lithographic printing plates obtained by the anodizing process and / or the pore wide process.

Further, the hydrophilic film may be an inorganic film provided by a sputtering method, a CVD method or the like in addition to the anodized film described above. Examples of the compound constituting the inorganic film include oxides, nitrides, silicides, borides, and carbides. Further, the inorganic film may be composed of only a single compound or a mixture of compounds. Specific examples of the compound constituting the inorganic film include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, hafnium oxide, vanadium oxide, niobium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, chromium oxide; aluminum nitride , Silicon nitride, titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, tantalum nitride, molybdenum nitride, tungsten nitride, chromium nitride, silicon nitride, boron nitride; Titanium silicide, zirconium silicide, hafnium silicide, vanadium silicide, niobium silicide, tantalum silicide, molybdenum silicide, tungsten silicide, chromium silicide; titanium boride, zirconium boride, hafnium boride, vanadium boride , Niobium boride, boride Tantalum, molybdenum boride, tungsten boride, chromium boride; aluminum carbide, silicon carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, and a chromium carbide.

<Sealing treatment>
In the present invention, the lithographic printing plate support of the present invention obtained by providing a hydrophilic film as described above may be subjected to a sealing treatment. Examples of the sealing treatment used in the present invention include sealing treatment of an anodized film with pressurized steam or hot water described in JP-A-4-176690 and JP-A-11-301135. In addition, silicate treatment, dichromate aqueous solution treatment, nitrite treatment, ammonium acetate treatment, electrodeposition sealing treatment, triethanolamine treatment, barium carbonate treatment, hydrothermal treatment containing a trace amount of phosphate It can also carry out using well-known methods, such as. For example, when the electrodeposition sealing process is performed, the sealing treatment film is formed from the bottom of the pore, and when the water vapor sealing process is performed, it is formed from the top of the pore. The formation of the pore-treated film is different. Other examples include immersion treatment with a solution, spray treatment, coating treatment, vapor deposition treatment, sputtering, ion plating, thermal spraying, and plating, but are not particularly limited. Among these, a sealing treatment using particles having an average particle diameter of 8 to 800 nm described in JP-A No. 2002-214764 is particularly preferable.

  The sealing treatment using the particles is performed with particles having an average particle diameter of 8 to 800 nm, preferably an average particle diameter of 10 to 500 nm, and more preferably an average particle diameter of 10 to 150 nm. Within this range, there is little risk of particles entering the inside of the micropores present in the hydrophilic film, sufficiently high sensitivity can be obtained, and sufficient adhesion with the image recording layer can be obtained, resulting in printing durability. Excellent in properties. The thickness of the particle layer is preferably 8 to 800 nm, and more preferably 10 to 500 nm.

  Examples of the method for providing the particle layer include, but are not limited to, immersion treatment with a solution, spray treatment, coating treatment, electrolytic treatment, vapor deposition treatment, sputtering, ion plating, thermal spraying, and plating.

  For the electrolytic treatment, direct current or alternating current can be used. Examples of the alternating current waveform used in the electrolytic treatment include a sine wave, a rectangular wave, a triangular wave, and a trapezoidal wave. The frequency of the alternating current is preferably 30 to 200 Hz, and more preferably 40 to 120 Hz, from the viewpoint of the cost of manufacturing the power supply device. When a trapezoidal wave is used as the waveform of the alternating current, the time tp until the current reaches a peak from 0 is preferably 0.1 to 2 msec, and more preferably 0.3 to 1.5 msec. If the tp is less than 0.1 msec, the impedance of the power supply circuit is affected, and a large power supply voltage is required at the rising of the current waveform, which may increase the equipment cost of the power supply.

As the hydrophilic particles, Al ₂ O ₃ , TiO ₂ , SiO ₂ and ZrO ₂ are preferably used alone or in combination of two or more. The electrolytic solution is obtained, for example, by suspending the hydrophilic particles in water or the like so that the content becomes 0.01 to 20% by mass of the whole. The electrolytic solution can be adjusted in pH by, for example, adding sulfuric acid in order to charge the charge positively or negatively. The electrolytic treatment is performed, for example, using a direct current, an aluminum plate as a cathode, the above electrolytic solution, and a voltage of 10 to 200 V for 1 to 600 seconds. According to this method, it is possible to easily close the mouth while leaving a void inside the micropore existing in the anodized film.

  Further, the sealing treatment is selected from the group consisting of at least one amino group, a carboxyl group and a salt group thereof, and a sulfo group and a salt group described in JP-A-60-149491. A layer composed of a compound having at least one group, selected from compounds having at least one amino group and at least one hydroxy group described in JP-A-60-232998 and salts thereof A layer comprising a compound, a layer containing a phosphate described in JP-A-62-19494, and at least one monomer unit having a sulfo group described in JP-A-59-101651 The method of providing the layer etc. which consist of a high molecular compound which has in a molecule | numerator as a unit by coating is mentioned.

  In addition, carboxymethyl cellulose; dextrin; gum arabic; phosphonic acids having an amino group such as 2-aminoethylphosphonic acid; phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, which may have a substituent, Organic phosphonic acid such as methylene diphosphonic acid and ethylene diphosphonic acid; organic phosphoric acid ester such as phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent; Organic phosphinic acids such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid; amino acids such as glycine and β-alanine; hydrochlorides of amines having hydroxy groups such as hydrochloride of triethanolamine Provide a compound layer selected from The method may also be mentioned.

  In the sealing treatment, a silane coupling agent having an unsaturated group may be applied. Examples of the silane coupling agent include N-3- (acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, (3-acryloxypropyl) dimethylmethoxysilane, and (3-acryloxypropyl) methyldimethoxy. Silane, (3-acryloxypropyl) trimethoxysilane, 3- (N-allylamino) propyltrimethoxysilane, allyldimethoxysilane, allyltriethoxysilane, allyltrimethoxysilane, 3-butenyltriethoxysilane, 2- ( Chloromethyl) allyltrimethoxysilane, methacrylamidopropyltriethoxysilane, N- (3-methacryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, (methacryloxymethyl) dimethylethoxysilane, Tacryloxymethyltriethoxysilane, methacryloxymethyltrimethoxysilane, methacryloxypropyldimethylethoxysilane, methacryloxypropyldimethylmethoxysilane, methacryloxypropylmethyldiethoxysilane, methacryloxypropylmethyldimethoxysilane, methacryloxypropylmethyltriethoxysilane , Methacryloxypropylmethyltrimethoxysilane, methacryloxypropyltris (methoxyethoxy) silane, methoxydimethylvinylsilane, 1-methoxy-3- (trimethylsiloxy) butadiene, styrylethyltrimethoxysilane, 3- (N-styrylmethyl-2) -Aminoethylamino) -propyltrimethoxysilane hydrochloride, vinyldimethylethoxysilane, vinyldiphenyl ester Xysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, O- (vinyloxyethyl) -N- (triethoxysilylpropyl) urethane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri-t-butoxysilane, vinyltriisopropoxy Examples include silane, vinyltriphenoxysilane, vinyltris (2-methoxyethoxy) silane, and diallylaminopropylmethoxysilane. Of these, a silane coupling agent having a methacryloyl group or an acryloyl group having a fast reactivity of the unsaturated group is preferable.

In addition to this, the sol-gel coating treatment described in JP-A-5-50779, the phosphonic acid coating treatment described in JP-A-5-246171, JP-A-6-234284, JP-A-6-6 No. 19173 and JP-A-6-230563, a method of treating a backcoat material by coating, treatment of phosphonic acids described in JP-A-6-262872, and JP-A-6-297.
875, coating treatment described in JP-A-10-109480, anodizing method described in JP-A-10-109480, immersion described in JP-A-2000-81704 and JP-A-2000-89466 Any of these methods may be used.

  After forming the hydrophilic film, the surface of the aluminum plate is subjected to a hydrophilic treatment as necessary. The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in each specification of No.272.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support of the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body of this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

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

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

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the image recording layer and the support, if necessary. Since the undercoat layer functions as a heat insulating layer, heat generated by exposure with an infrared laser is not diffused to the support and can be used efficiently, so that there is an advantage that high sensitivity can be achieved. In addition, in the unexposed area, the image recording layer is easily peeled off from the support, so that the on-press developability is improved.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the described ethylenic double bond reactive group etc. are mentioned suitably.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

[Protective layer]
In the lithographic printing plate precursor according to the present invention, a protective layer is provided on the image recording layer as necessary in order to prevent the occurrence of scratches in the image recording layer, to block oxygen, and to prevent ablation during high-illuminance laser exposure. Can do.
In the present invention, the exposure is usually performed in the air, but the protective layer is an image of low molecular weight compounds such as oxygen and basic substances present in the air that inhibit the image forming reaction caused by exposure in the image recording layer. This prevents the recording layer from being mixed, and prevents the image formation reaction from being hindered by exposure in the air. Therefore, the properties desired for the protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion to the image recording layer, and It is preferable that it can be easily removed in an on-press development process after exposure. Various studies have been made on the protective layer having such characteristics, and are described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

  Examples of the material used for the protective layer include water-soluble polymer compounds that are relatively excellent in crystallinity. Specific examples include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic acid. Among these, when polyvinyl alcohol (PVA) is used as a main component, the best results are obtained for basic characteristics such as oxygen barrier properties and development removability. The polyvinyl alcohol may be partially substituted with an ester, ether or acetal as long as it contains an unsubstituted vinyl alcohol unit for providing the oxygen barrier property and water solubility necessary for the protective layer, and a part of the other You may have a copolymerization component.

  As specific examples of polyvinyl alcohol, those having a hydrolysis degree of 71 to 100 mol% and a polymerization degree of 300 to 2400 are preferably mentioned. Specifically, for example, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA- HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, and L-8 are mentioned.

The components of the protective layer (selection of PVA, use of additives, etc.), coating amount, etc. are appropriately selected in consideration of fogging properties, adhesion, scratch resistance, etc. in addition to oxygen barrier properties and development removability. Generally, the higher the hydrolysis rate of PVA (that is, the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), and the thicker the film thickness, the higher the oxygen barrier property, which is preferable in terms of sensitivity. . Further, in order to prevent unnecessary polymerization reaction during production and storage, unnecessary fogging during image exposure, image line thickening, and the like, it is preferable that the oxygen permeability is not excessively high. Therefore, 25 ° C,
The oxygen permeability A at 1 atm is preferably 0.2 ≦ A ≦ 20 (cc / m ² · day).

As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the water-soluble polymer compound, and flexibility can be imparted. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.
The thickness of the protective layer is suitably from 0.1 to 5 μm, particularly preferably from 0.2 to 2 μm.

  In addition, adhesion to the image area, scratch resistance, and the like are extremely important in handling the lithographic printing plate precursor. That is, when a protective layer that is hydrophilic because it contains a water-soluble polymer compound is laminated on the image recording layer when the image recording layer is oleophilic, the protective layer is liable to peel off due to insufficient adhesion, and the peeling occurs. In some parts, defects such as poor film hardening due to inhibition of polymerization by oxygen may occur.

  On the other hand, various proposals have been made to improve the adhesion between the image recording layer and the protective layer. For example, JP-A-49-70702 and British Patent Application No. 1303578 disclose an acrylic emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, etc. in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on an image recording layer. Any of these known techniques can be used in the present invention. The method for applying the protective layer is described in detail, for example, in US Pat. No. 3,458,311 and JP-B-55-49729.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

〔exposure〕
In the planographic printing method of the present invention, the above-described planographic printing plate precursor of the present invention is imagewise exposed with an infrared laser.
Although the infrared laser used for this invention is not specifically limited, The solid laser and semiconductor laser which radiate | emit infrared rays with a wavelength of 760-1200 nm are mentioned suitably. The output of the infrared laser is preferably 100 mW or more. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.
The exposure time per pixel is preferably within 20 μsec. Moreover, it is preferable that irradiation energy amount is 10-300 mJ / cm < ² >.

[Printing method]
The lithographic printing plate precursor according to the present invention is imagewise exposed with an infrared laser, and then supplied with oil-based ink and aqueous component without any development processing step.
Specifically, after exposing the lithographic printing plate precursor with an infrared laser, it is mounted on a printing press plate cylinder without passing through a development process, and the lithographic printing plate precursor is placed on the printing plate cylinder. Examples of the method include a method of performing exposure with an infrared laser on a printing machine after printing and printing without going through a development process.

For example, in one embodiment of a negative on-press development type lithographic printing plate precursor, an aqueous component and an oily composition are used without undergoing a development processing step such as a wet development processing step after exposing the lithographic printing plate precursor imagewise with an infrared laser. When ink is supplied and printing is performed, in the exposed portion of the image recording layer, the image recording layer cured by exposure forms an oil-based ink receiving portion having a lipophilic surface. On the other hand, in the unexposed area, the uncured image recording layer is dissolved or dispersed and removed by the supplied aqueous component and / or oil-based ink, and a hydrophilic surface is exposed in that area. As a result, the aqueous component adheres to the exposed hydrophilic surface, and the oil-based ink is deposited on the image recording layer in the exposed area, and printing is started. Here, the water-based component or oil-based ink may be first supplied to the plate surface, but the oil-based ink is first used in order to prevent the water-based component from being contaminated by the image recording layer in the unexposed area. It is preferable to supply. As the aqueous component and oil-based ink, a dampening water and printing ink for ordinary lithographic printing are used. In this way, the lithographic printing plate precursor is subjected to on-press development on an offset printing machine and used as it is for printing a large number of sheets.

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

(Preparation of color change agent dispersion)
(1) Preparation of Discolorant Dispersion Liquid (1) The mixture of the following discolorant dispersion liquid (1) added with each component was stirred for 30 minutes with a φ4 mm glass bead in a paint shaker to obtain a rough color change agent. A dispersion was obtained. After the glass beads were separated by filtration, glass beads having a diameter of 0.5 mm were further added, and this was dispersed with a dynomill under conditions of a liquid flow rate and a cell volume that would give a residence time of about 20 minutes. The glass beads were separated by filtration to obtain a color changer dispersion (1) containing color changer particles having an average particle size of 0.12 μm.

Dispersant dispersion (1)
-1.0g of the following discoloring agent (1)
・ Solsperth S-17000 (ICI dispersant) 0.2 g
・ Isopar G (ExxonMobil hydrocarbon solvent) 10.8g

(2) Preparation of Color Changer Dispersion (2) The average particle diameter was the same as that for the color change dispersion (1) except that the composition of the color change dispersion was changed to the following color change dispersion (2). A color changing agent dispersion (2) containing 0.08 μm color changing agent particles was obtained.

Dispersant dispersion (2)
-1.0 g of the above color change agent (1)
・ Solsperse S-27000 (dispersant made by ICI) 0.04 g
・ Pure water 9.0g

(3) Preparation of Color Changer Dispersion Liquid (3) The average particle diameter was the same as that for the color change agent dispersion liquid (1) except that the composition of the color change agent dispersion liquid was changed to the following color change agent dispersion liquid (3). A color change agent dispersion (3) containing 0.12 μm color changer particles was obtained.

Dispersant dispersion (3)
-1.0g of the following discoloring agent (2)
-Solsperse S-17000 (Dispersant manufactured by ICI) 0.2 g
・ Isopar G (hydrocarbon solvent manufactured by ExxonMobil Co., Ltd.) 10.8 g

(4) Preparation of Color Changer Dispersion (4) Average particle size was the same as that of Color Changer Dispersion (1) except that the composition of the color changer dispersion was changed to the following Color Changer Dispersion (4) A color changing agent dispersion (4) containing 0.08 μm color changing agent particles was obtained.

Dispersant dispersion (4)
-1.0 g of the above color change agent (2)
・ Solsperse S-27000 (dispersant made by ICI) 0.04 g
・ Pure water 9.0g

(5) Preparation of Color Changer Dispersion Liquid (5) The average particle diameter was the same as that for the color change agent dispersion liquid (1) except that the composition of the color change agent dispersion liquid was changed to the following color change agent dispersion liquid (5). A color change dispersion (5) containing 0.18 μm color changer particles was obtained.

Dispersant dispersion (5)
・ Leuco Crystal Violet (Tokyo Chemical Industry Co., Ltd.) 1.0g
-Solsperse S-17000 (Dispersant manufactured by ICI) 0.2 g
・ Isopar G (hydrocarbon solvent manufactured by ExxonMobil Co., Ltd.) 10.8 g

(6) Preparation of Color Changer Dispersion Liquid (6) The average particle diameter was the same as that for the color change agent dispersion liquid (1) except that the composition of the color change agent dispersion liquid was changed to the following color change agent dispersion liquid (6). A color changing agent dispersion (6) containing 0.10 μm color changing particles was obtained.

Dispersant dispersion (6)
・ Leuco Crystal Violet (Tokyo Chemical Industry Co., Ltd.) 1.0g
・ Solsperse S-27000 (dispersant made by ICI) 0.04 g
・ Pure water 9.0g

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

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried.

  Next, it processed for 10 second at 30 degreeC with 2.5 mass% sodium silicate aqueous solution. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Furthermore, the following undercoat liquid (1) was applied so that the dry coating amount was 10 mg / m ² to prepare a support used in the following experiments.

Undercoat liquid (1)
・ Undercoat compound (1) below 0.017g
・ Methanol 9.00 g
・ Water 1.00g

[Examples 1 to 14 and Comparative Examples 1 to 4]
Lithographic printing plate precursors (1) to (18) were prepared and then evaluated.

[Preparation of lithographic printing plate precursor]
(1) Preparation of lithographic printing plate precursor (1) An image recording layer coating solution (1) having the following composition was bar-coated on the support, and then oven-dried at 100 ° C. for 60 seconds to obtain a dry coating amount of 1. An image recording layer of 0 g / m ² was formed.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microcapsule solution (1) immediately before coating.

Photosensitive solution (1)
・ The following binder polymer (1) 0.162 g
-0.1 g of the following polymerization initiator (1)
・ The following infrared absorbing dye (1) 0.020 g
・ Polymerizable compound (Aronix M215, manufactured by Toagosei Co., Ltd.) 0.385 g
-0.044 g of the following fluorosurfactant (1)
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

Microcapsule liquid (1)
・ Microcapsule synthesized as follows (1) 2.640 g
・ Water 2.425g

(Synthesis of microcapsule (1))
As oil phase components, trimethylolpropane and xylene diisocyanate adduct (Mitsui Takeda Chemical Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, Infrared absorber (2) 0.35 g, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane (ODB manufactured by Yamamoto Kasei Co., Ltd.) 1 g, and pionine A-41C (Takemoto) 0.1 g of Oils and Fats Co., Ltd. was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of PVA-205 was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 40 ° C. for 3 hours. The microcapsule solution thus obtained was diluted with distilled water so that the solid content concentration was 15% by mass. The average particle size was 0.2 μm.

(Discoloration layer formation)
On the image recording layer, a color change layer coating solution (1) having the following composition was bar coated, followed by oven drying at 100 ° C. for 60 seconds to form a color change layer having a dry coating amount of 1.0 g / m ² .

Discoloration layer coating solution (1)
-15.5g of said discolorant dispersion liquid (1)
・ Perfluorobutanesulfonic acid 1.0 g
・ 0.044 g of the above fluorosurfactant (1)

(Formation of protective layer)
On the discoloration layer, a protective layer coating solution (1) having the following composition was further bar-coated, followed by oven drying at 100 ° C. for 75 seconds to form a protective coating layer having a dry coating amount of 0.1 g / m ^2. The lithographic printing plate precursor (1) used in Example 1 was obtained.

Protective layer coating solution (1)
・ Polyvinyl alcohol (Poval PVA105) 0.895g
(Kuraray Co., Ltd., saponification degree 98-99 mol%, polymerization degree 500)
・ Polyvinylpyrrolidone (K30) 0.035g
(Wako Pure Chemical Industries, Ltd., weight average molecular weight 400,000)
・ Polyvinylpyrrolidone copolymer (Lubicol VA64W) 0.048g
BASF Japan KK, weight average molecular weight 34,000 vinylpyrrolidone / vinyl acetate (molar ratio = 60/40) copolymer,
50% by weight aqueous solution-Nonionic surfactant 0.020g
(Product name: EMALEX 710, manufactured by Nippon Emulsion Co., Ltd.)
・ Water 15.200g

(2) Preparation of lithographic printing plate precursor (2) The protective layer coating solution (1) is changed to the protective layer coating solution (2) having the following composition without providing the discoloration layer described in the preparation of the lithographic printing plate precursor (1). A lithographic printing plate precursor (2) used in Example 2 was obtained in the same manner as in the production of the lithographic printing plate precursor (1) except that the dry coating amount was changed to 1.0 g / m ² .

Protective layer coating solution (2)
・ Polyvinyl alcohol (Poval PVA105) 0.895g
・ Polyvinylpyrrolidone (K30) 0.035g
・ Nonionic surfactant 0.020g
・ Discolorant dispersion liquid (2) 1.000 g
・ P-toluenesulfonic acid 0.100 g
・ Water 15.200g

(3) Preparation of lithographic printing plate precursor (3) The discoloration layer described in the preparation of the lithographic printing plate precursor (1) is not provided, and the image recording layer coating liquid (1) is used as the following image recording layer coating liquid (2). A lithographic printing plate precursor (3) used in Example 3 was obtained in the same manner as in the preparation of the lithographic printing plate precursor (1) except that The image recording layer coating solution (2) was obtained by mixing the photosensitive solution (1) and the following microcapsule solution (2) immediately before coating.

Microcapsule liquid (2)
-Microcapsules synthesized as described above (1) 2.640 g
・ Discolorant dispersion liquid (2) 1.000 g
・ Methanesulfonic acid 0.100g
・ Water 1.425g

(4) Preparation of lithographic printing plate precursor (4) The image recording layer coating solution (1) described in the preparation of the lithographic printing plate precursor (1) was changed to an image recording layer coating solution (3) having the following composition. A lithographic printing plate precursor (4) used in Example 4 was obtained in the same manner as the production of the lithographic printing plate precursor (1).

Image recording layer coating solution (3)
・ The following infrared absorber (2) 0.05 g
・ 0.1 g of the above polymerization initiator (1)
-0.50 g of the following binder polymer (2)
Polymerizable compound, Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 1.00 g
・ 0.044 g of the above fluorosurfactant (1)
・ Methyl ethyl ketone 18.0g

(5) Preparation of lithographic printing plate precursor (5) A lithographic process except that the image recording layer coating solution (1) described in the preparation of the lithographic printing plate precursor (2) is changed to the image recording layer coating solution (3). A lithographic printing plate precursor (5) used in Example 5 was obtained in the same manner as the preparation of the printing plate precursor (2).

(6) Preparation of lithographic printing plate precursor (6) Lithographic printing plate except that the image recording layer coating solution (2) described in the preparation of the lithographic printing plate precursor (3) is changed to the image recording layer coating solution (4) A lithographic printing plate precursor (6) used in Example 6 was obtained in the same manner as in preparation of the precursor (3). The image recording layer coating solution (4) was obtained by mixing the following photosensitive solution (2) and the following color change agent dispersion immediately before coating.

Photosensitive solution (2)
・ 0.05g of the above infrared absorber (2)
・ 0.1 g of the above polymerization initiator (1)
-0.50 g of the above binder polymer (2)
Polymerizable compound, Aronix M-215 (manufactured by Toa Gosei Co., Ltd.) 1.00 g
・ 0.044 g of the above fluorosurfactant (1)
・ Methyl ethyl ketone 1.0g
・ 9.0 g of 1-methoxy-2-propanol

Discoloring agent dispersion-1.000 g of the above discoloring agent dispersion (2)
・ Methanesulfonic acid 0.100g

(7) Preparation of lithographic printing plate precursors (7) to (9) The color change agent dispersions (1) and (2) described in the preparation of the above lithographic printing plate precursors (1) to (3) Example 7 corresponding to each of the lithographic printing plate precursors (1) to (3) in the same manner as the production of the lithographic printing plate precursors (1) to (3) except that the liquids (3) and (4) were changed, respectively. The lithographic printing plate precursors (7) to (9) used for .about.9 were obtained.

(8) Preparation of lithographic printing plate precursors (10) to (12) The color change agent dispersions (1) and (2) described in the preparation of the lithographic printing plate precursors (1) to (3) are dispersed in the color change agent. Example 10 corresponding to each of the lithographic printing plate precursors (1) to (3) in the same manner as the production of the lithographic printing plate precursors (1) to (3) except that the liquids (5) and (6) were changed, respectively. The lithographic printing plate precursors (10) to (12) used for -12 were obtained.

(9) Preparation of lithographic printing plate precursor (13) Comparative example is similar to the preparation of lithographic printing plate precursor (1) except that the discoloration layer described in the preparation of lithographic printing plate precursor (1) is not provided. A lithographic printing plate precursor (13) used in No. 1 was obtained.

(10) Preparation of lithographic printing plate precursor (14) The discoloration layer described in the preparation of the lithographic printing plate precursor (1) is not provided, and the image recording layer coating solution (1) is dissolved in the discoloring agent (1). A lithographic printing plate precursor (14) used in Comparative Example 2 was obtained in the same manner as in the production of the lithographic printing plate precursor (1) except that the image recording layer coating liquid (5) was changed. The image recording layer coating solution (5) was obtained by mixing the following photosensitive solution (3) and the microcapsule solution (1) immediately before coating.

Photosensitizer (3)
-0.162 g of the above binder polymer (1)
・ 0.1 g of the above polymerization initiator (1)
・ The above infrared absorbing dye (1) 0.020 g
・ Polymerizable compound (Aronix M215, manufactured by Toagosei Co., Ltd.) 0.385 g
・ 0.1 g of the above color change agent (1)
・ 0.044 g of the above fluorosurfactant (1)
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

(11) Preparation of lithographic printing plate precursor (15) The discoloring agent (1) added to the photosensitive solution (3) described in the preparation of the lithographic printing plate precursor (14).
) Was changed to leuco crystal violet (manufactured by Tokyo Kasei Kogyo Co., Ltd.), in the same manner as the production of the lithographic printing plate precursor (14), a lithographic printing plate precursor (15) used in Comparative Example 3 was obtained. .

(12) Preparation of lithographic printing plate precursor (16) The following image recording layer coating solution (6) was bar-coated on the above support having an undercoat layer, then oven-dried at 70 ° C. for 60 seconds and dried. An image recording layer having a coating amount of 0.6 g / m ² was produced.

Image recording layer coating solution (6)
・ 33.0 g of polymer fine particle aqueous dispersion prepared as follows
・ The following infrared absorbing dye (3) 1.0 g
-10.0g of said discolorant dispersion liquid (2)
・ Methanesulfonic acid 0.1g
・ Pentaerythritol tetraacrylate 0.5g
・ Methanol 16.0g

(Production of polymer fine particle aqueous dispersion)
A 1000 ml four-necked flask is equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube and reflux condenser, and 350 cc of distilled water is added while deoxygenating by introducing nitrogen gas, and the internal temperature becomes 80 ° C. Until heated. Add 1.5 g of sodium dodecyl sulfate as a dispersant, 0.45 g of ammonium persulfide as an initiator, and then add a mixture of 45.0 g of glycidyl methacrylate and 45.0 g of styrene from the dropping funnel to about 1 It was added dropwise over time. After the completion of the dropwise addition, the reaction was continued as it was for 5 hours, and then the unreacted monomer was removed by steam distillation. Thereafter, the mixture was cooled and adjusted to pH 6 with ammonia water, and finally pure water was added so that the non-volatile content was 15% by mass to obtain an aqueous polymer polymer fine particle dispersion. The particle size distribution of the polymer fine particles had a maximum value at a particle size of 60 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. And the frequency of appearance of each particle size was plotted and obtained. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

Further, the following protective layer coating solution (3) was bar-coated thereon, followed by oven drying at 60 ° C. for 120 seconds to form a protective layer having a dry coating amount of 0.3 g / m ² and used in Example 13. A lithographic printing plate precursor (16) was obtained.

Protective layer coating solution (3)
・ Carboxymethylcellulose (weight average molecular weight 20,000) 5.0 g
・ Water 50.0g

(13) Preparation of lithographic printing plate precursor (17) The image recording layer coating solution (6) and the protective layer coating solution (3) described in the preparation of the lithographic printing plate precursor (16) are respectively applied to the following image recording layer coatings. A lithographic printing plate precursor (17) used in Example 14 was obtained in the same manner as in the production of the lithographic printing plate precursor (16) except that the liquid (7) and the protective layer coating liquid (4) were changed.

Image recording layer coating solution (7)
-Polymer fine particle aqueous dispersion prepared as above 33.0 g
・ 1.0g of the above infrared absorbing dye (3)
・ Pentaerythritol tetraacrylate 1.0g
・ Methanol 16.0g

Protective layer coating solution (4)
・ Carboxymethylcellulose (weight average molecular weight 20,000) 5.0 g
-10.0g of said discolorant dispersion liquid (2)
・ Methanesulfonic acid 0.1g
・ Water 50.0g

(14) Preparation of lithographic printing plate precursor (18) The image recording layer coating solution (6) described in the preparation of the lithographic printing plate precursor (16) was changed to the image recording layer coating solution (7). The lithographic printing plate precursor (18) used in Comparative Example 4 was obtained in the same manner as in the preparation of the lithographic printing plate precursor (16).

[Evaluation of planographic printing plate precursor]
(1) Evaluation of Print-out Image The obtained lithographic printing plate precursor was exposed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under the conditions of an output of 9 W, an outer drum rotational speed of 210 rpm, and a resolution of 2400 dpi. The exposure image includes a thin line chart and a character image.
In order to evaluate the printout image, the L * value of the exposed area and the unexposed area is measured using a color difference meter (color / color difference meter CR-221, manufactured by Minolta Co., Ltd.), and the brightness difference ΔL is determined from the absolute value of the difference. Asked.
The results are shown in Table 1. Except for Comparative Example 1, the contrast between the exposed area and the unexposed area was good, and fine lines and characters could be recognized.

(2) Evaluation of print-out fogging property over time of raw plate The obtained lithographic printing plate precursor was forcibly aged for 3 days in an environment of 60 ° C. and 30% RH without packaging.
In order to evaluate the print-out fogging property at this time, the L * value before and after forced aging was measured using the color difference meter, and the brightness difference ΔL was obtained from the absolute value of the difference.
The results are shown in Table 1. Except for Comparative Examples 2 and 3, the print-out fogging property with forced aging was good.

(3) Evaluation of printing fogging by white light exposure The obtained lithographic printing plate precursor was exposed to a commercially available fluorescent lamp for 6 hours so that the illuminance was 1000 lux on the plate surface.
In order to evaluate the print-out fogging property at this time, the L * value before and after white light exposure was measured using the color difference meter, and the brightness difference ΔL was obtained from the absolute value of the difference.
The results are shown in Table 1. Except for Comparative Examples 2 and 3, the print-out fogging with white light exposure was good.

(4) On-press developability and printing evaluation The obtained exposed original plate was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. Using fountain solution (IF-102 (Fuji Photo Film Co., Ltd.) / Water = 3/97 (volume ratio)) and TRANS-G (N) black ink (Dainippon Ink Chemical Co., Ltd.) After supplying dampening water and ink, 100 sheets were printed at a printing speed of 6000 sheets per hour.
When the on-machine development on the printing machine of the unexposed part of the image recording layer was completed and the number of printing papers required until the ink was not transferred to the printing paper was measured as on-machine developability, Even when the planographic printing plate precursor was used, a printed material having no stains on the non-image area was obtained within 20 sheets.
Further, when 5,000 sheets were printed thereafter, a good printed matter having no decrease in the ink density in the image area and no stain in the non-image area was obtained when any of the lithographic printing plate precursors was used.

(5) Ink turbidity evaluation 100 sheets in the same manner as in (4) above except that the ink described in (4) above was changed to TRANS-G (N) yellow ink (manufactured by Dainippon Ink & Chemicals, Inc.). Was printed. The turbidity of the image part ink of this printed matter was evaluated by an index described later.
The results are shown in Table 1. Except for Comparative Examples 2 and 3, the ink turbidity was good.

<Ink turbidity evaluation index>
A: No ink turbidity
B: Slightly cloudy but acceptable level
C: Clear turbidity NG level
D: Poor turbidity

  As is apparent from Table 1, the lithographic printing plate precursors (Examples 1 to 14) of the present invention clearly formed a sufficient print-out image for plate inspection after laser exposure, and the raw plate It can be seen that there is very little printout due to aging or exposure to white light. Furthermore, it can be seen that there is almost no ink turbidity due to mixing of on-press development components after printing, and a good printed matter can be obtained.

Example 15
A lithographic printing plate precursor was prepared, printed and evaluated in the same manner as in Example 3 except that the following microgel solution (1) was used instead of the microcapsule solution (1) in Example 3.
ΔL during exposure was 12.0, fog over time ΔL was 0.2, white light fog ΔL was 0.2, on-press development was good, printing evaluation was good, and ink turbidity was A.

Microgel solution (1)
-Microgel (1) synthesized as follows: 2.640 g
・ Distilled water 2.425g

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

Claims (7)

  A lithographic printing plate precursor having an image recording layer on a support and capable of being printed without being subjected to a development processing step after being imagewise exposed, comprising (A) an infrared absorber and (D) a color change agent And (E) a developer, and the color changer is a particle, and melts with heat generated by exposure and interacts with the developer to cause a change in absorbance in the visible light region. A lithographic printing plate precursor.   The lithographic printing plate precursor as claimed in claim 1, wherein the image recording layer contains (A) an infrared absorber, (B) a polymerization initiator, and (C) a polymerizable compound.   The lithographic printing plate precursor as claimed in claim 1, wherein the image recording layer comprises (A) an infrared absorber and (F) hydrophobic thermoplastic polymer particles.   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the image recording layer is a crosslinked hydrophilic layer.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the image recording layer comprises a microcapsule or a microgel.   A method for producing a lithographic printing plate precursor that is image-wise exposed and can be printed without undergoing a development process, and melts with the heat generated by the exposure and interacts with the developer in the visible light region. Production of a lithographic printing plate precursor comprising dispersing a color changing agent causing a change in absorbance in the form of a coating solution containing a color developer, applying the liquid, and then drying under a condition that the color changing agent particles do not melt. Method. A printing method comprising the following steps.
(1) A step of imagewise exposing the lithographic printing plate precursor according to any one of claims 1 to 5.
(2) A step of mounting the lithographic printing plate precursor on a plate cylinder of a printing machine.
(3) A step of printing by supplying printing ink and fountain solution onto the exposed lithographic printing plate precursor on the printing plate cylinder.
However, the steps (1) and (2) may be performed in reverse order.