JP2005305903A - Original lithographic printing plate, method for manufacturing original lithographic printing plate and lithographic printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an original lithographic printing plate of the aboard-the-machine development type or unprocessing (undevelopment) type, on which an image can be drawn by exposing the plate to an infrared laser light; shows excellent resistance to plate wear and visibility of the printing plate after exposure, and a lithographic printing method using the original lithographic printing plate of the aboard-the-machine development type. <P>SOLUTION: The original lithographic printing plate has a photosensitive/heat-sensitive layer formed on a support; can have an image drawn by infrared laser exposure; and is mounted on a printer without passing through a development process after image recording or can serve for printing work by recording the image after mounting the plate onto the printer. The photosensitive/heat-sensitive layer contains an infrared absorbing agent, a basic generator and a basic discoloration agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor, a method for making a lithographic printing plate, and a lithographic printing method using the lithographic printing plate. 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 without being subjected to a development processing step after exposure, The present invention relates to a plate making method of the lithographic printing plate and a lithographic 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, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image forming 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 is left, 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.

  On the other hand, the non-processing (non-development) 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 an fountain solution, an ink solvent, or an emulsion of a fountain solution and an ink. , A method of mechanically removing the image recording layer by contact with rollers or a blanket cylinder of a printing press, cohesion force of the image recording layer by penetration of dampening water, ink solvent, etc., or between the image recording layer and the support. 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 process of removing the infrared laser unexposed portion of the lithographic printing plate precursor 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 method 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 before being 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, simplification, drying, and no processing of plate making operations have become more desirable than ever in terms of both consideration for the global environment and adaptation to digitalization. It is coming.

Recently, high-power lasers such as semiconductor lasers that emit infrared rays having a wavelength of 760 to 1200 nm, YAG lasers, etc. have become available at a low cost. Therefore, a method using these high-power lasers as an image recording means has been considered 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. On the other hand, in the method using the above-described high-power laser, a large amount of light energy is irradiated to the exposure region in a very 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 form or a 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 a plate-making process is performed by on-press development, the exposed image recording layer is imaged to form a lithographic printing plate. 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 generator 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 machine, there are operations such as 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 it is. Done. Ordinary planographic printing plate precursors with development processing steps are generally performed by coloring the image recording layer so that the image can be printed after plate making (after development processing) and before printing (before attaching the printing plate to the printing press). It is easy to confirm.
However, in the case of the on-machine development type or the non-processing (no development) type lithographic printing plate precursor which does not involve a development processing step before the conventional printing as proposed in the above-mentioned Patent Documents 2 and 3, the printing plate is a printing machine. At the stage of attaching to the plate, there was a problem that there was no image on the printing plate and the plate could not 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 multicolor printing is clearly drawn is important for the printing operation. The present invention solves this problem.
That is, an object of the present invention is an on-press development type or non-processed (no development) type lithographic printing plate precursor having good printing durability and good visibility of the plate after exposure, and the lithographic printing plate precursor And a printing method using the planographic printing plate precursor.

As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by using a base generator and a base discoloring agent in combination.
The present invention has been made based on the above findings, and specifically, is as follows.

(1) A lithographic printing plate precursor having at least an image forming layer capable of recording an image by infrared laser exposure on a support, wherein at least one layer of the lithographic printing plate precursor comprises (A) an infrared absorber, (B A lithographic printing plate precursor comprising a base generator and (C) a base discoloring agent and having a color change between an exposed area and an unexposed area.
(2) A layer containing (A) an infrared absorber, (B) a base generator, and (C) a base discoloring agent and adapted to cause a color change between an exposed area and an unexposed area, The lithographic printing plate precursor as described in (1), which comprises (D) a radically polymerizable compound and (E) a radical polymerization initiator.
(3) A layer containing (A) an infrared absorber, (B) a base generator, and (C) a base discoloring agent so that a color change occurs between an exposed portion and an unexposed portion. The lithographic printing plate precursor as described in (1) or (2), which is a layer.
(4) It contains the support, the (A) infrared absorber, the (B) base generator, and the (C) base discoloring agent so that a color change occurs between the exposed portion and the unexposed portion. The lithographic printing plate precursor as described in (1), wherein a layer containing (D) a radical polymerizable compound and (E) a radical polymerization initiator is provided between the two layers.
(5) The lithographic printing plate precursor can be printed by mounting on a printing machine without passing through a development process after image recording by laser exposure, or by recording an image after mounting the printing machine. A lithographic printing plate precursor.
(6) The printing press after the lithographic printing plate precursor according to any one of (1) to (5) is mounted on a printing machine and imagewise exposed with an infrared laser, or imagewise exposed with an infrared laser A method for making a lithographic printing plate precursor, comprising: removing the unexposed portion of the image forming layer from an infrared laser by supplying printing ink and fountain solution to the lithographic printing plate precursor.
(7) The printing press after the lithographic printing plate precursor according to any one of (1) to (5) is mounted on a printing machine and imagewise exposed with an infrared laser, or imagewise exposed with an infrared laser A lithographic printing method in which a printing ink and a fountain solution are supplied to the lithographic printing plate precursor to remove an infrared laser unexposed portion of the image forming layer.

  According to the present invention, an on-press development type or unprocessed (no development) type lithographic printing plate precursor having good printing durability and good visibility of the plate after exposure, and plate making of the lithographic printing plate precursor And a lithographic printing method using the lithographic printing plate precursor.

Hereinafter, the lithographic printing plate precursor according to the invention will be described in detail.
The lithographic printing plate precursor according to the invention comprises at least an image forming layer on a hydrophilic support. Examples of such a lithographic printing plate precursor include (i) on-press development type lithographic printing plate precursor and (ii) no treatment (no development type) lithographic printing plate precursor shown below.

(I) On-press development type lithographic printing plate precursor:
It has an image forming layer in which the solubility or dispersibility in fountain solution and / or ink is changed by exposure, or the adhesiveness to an adjacent layer having a 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 a printing machine after exposure.

(Ii) Unprocessed (no development type) lithographic printing plate precursor:
A lithographic printing plate precursor which has an image forming layer whose affinity for fountain solution or ink changes on the surface by exposure, and can be printed after image exposure without removing the image forming layer.

  Among these, the on-press development type lithographic printing plate precursor has a higher mobility in a color changing system in which a color change is caused by exposure in the image forming layer because the image forming layer does not necessarily have a crosslinked structure as described later. In addition, the color change reactivity is likely to be improved. Accordingly, (i) on-press development type lithographic printing plate precursor is more preferable than (ii) no-treatment (no development) type in which the image forming layer has a crosslinked structure.

  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 2001-162960 Gazettes, International Publication No. 00/16987, International Publication No. 01/39985, European Patent Application Publication No. 990517, European Patent Application Publication No. 1225041, United States Patent Nos. 6465152, JP-A-6-317899, WO96 / 35143 pamphlet, European Patent Application No. 652483, JP-A-10-10737, JP-A-11-309952 Each publication, US Pat. No. 6,176,677, US Pat. No. 6,436,694 It is possible to adopt the basic structure of the plate member according to each specification and the like of.

  The constituent elements of the planographic printing plate precursor of the present invention will be described in detail below.

  In the lithographic printing plate precursor according to the present invention, a base is generated from the base generator by the heat generated by the infrared absorbent by the infrared laser exposure, and the color of the base discoloring agent is changed by the action of the base. By this color change, a difference in hue and brightness between the exposed portion and the unexposed portion, that is, a so-called printout image is generated, and good visibility is obtained.

A layer containing (A) an infrared absorber, (B) a base generator, and (C) a base discoloring agent according to the present invention so that a color change occurs between an exposed area and an unexposed area (hereinafter referred to as the present invention). (It may be abbreviated as a layer containing the components (A) to (C) of the invention.).
In the lithographic printing plate precursor according to the present invention, the layer containing the components (A) to (C) of the present invention is not particularly limited, and may be an image forming layer or other layers (such as an overcoat layer).
In addition, the layer containing the components (A) to (C) of the present invention is not a layer having an affinity for the ink itself, but a layer having an affinity for the ink is provided separately. It can also be designed as a layer adjacent to a certain layer.
Below, the structural component of the layer containing component (A)-(C) is demonstrated.

[Infrared absorber]
The said infrared absorber used for this invention is a component used in order to raise the sensitivity with respect to an infrared laser. The infrared absorber has a function of converting absorbed infrared rays into heat. The infrared absorber used in the present invention is preferably 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- 41363, 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US Pat. 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 U.S. Pat. No. 4,756,993 as formulas (I) and (II).
Other preferable examples of the infrared absorbing dye 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, 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 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. Here, the hetero atom represents N, S, O, a halogen atom, or Se. Xa ^- the Za described later ^- is defined as for, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the 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 from the viewpoint of storage stability of the recording layer coating solution, and particularly preferably a perchlorate ion, a hexagonal ion. 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 ,
Kinophthalone 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 Applications 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 forming layer coating solution and good uniformity of the image forming 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, or may be composed of two or more layers and added to a separate layer from the other components. Moreover, it can also be included in a microcapsule and added.
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 forming layer is in the range of 0.3 to 1.2 by the reflection measurement method. It is preferable to add so that it may exist in this, More preferably, it is the range of 0.4-1.1. Within this range, a uniform polymerization reaction proceeds in the depth direction of the image forming layer, and good film strength of the image area and adhesion to the support can be obtained. The absorbance of the image forming layer can be adjusted by the amount of the infrared absorber added to the image forming layer and the thickness of the image forming layer. Absorbance can be measured by a conventional method. As a measuring method, for example, on a reflective support such as aluminum, an image forming 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.

[Base generator]
Examples of the base generator used in the present invention include compounds described in JP-A-2-166450, page 6, upper left line, second line to upper right line, 15th line, specifically, Some compounds that release some bases by heating, such as salts of organic acids and bases decarboxylated by heating, compounds that release amines by reactions such as intramolecular nucleophilic substitution, Lossen transfer, Beckmann transfer, etc. Preferably used.
Specific examples include base acid salts. Examples of the base include guanidine, triphenylguanidine, tricyclohexylguanidine, piperidine, morpholine, p-toluidine, and 2-picoline. Examples thereof include acetic acid, trichloroacetic acid, phenylsulfonylacetic acid, 4-methylsulfonylphenylsulfonylacetic acid, 4-acetylaminomethylpropionic acid, succinic acid, maleic acid, succinic acid, fumaric acid, carbonic acid, and bicarbonate.
These base generators may be dispersed in the composition for the image forming layer in a solid state and introduced into the layer as particulate matter, or introduced in the state of being encapsulated in microcapsules described later. You may do it.
The addition amount of the base generator is preferably 10 to 1000 parts by mass with respect to 100 parts by mass of the infrared absorber, from the viewpoint of visibility of the exposed part, and more preferably 30 to 800 parts by mass. preferable.

[Base discoloring agent]
As the base discoloring agent used in the present invention, any compound that develops, decolors, or discolors with a base can be suitably used.
Among such base discoloring agents, examples of compounds that can be decolored or discolored by a base include polymethine dyes such as cyanine dyes. Preferred examples of such compounds include
STAINS-ALL, sulfopropylsulfopropyl-naphthothiazoylidenemethylbutynylnaphthothiazole, 3,3′-diethylselenacarbocyanine iodide, 2- {4- (dimethylamino) styryl} -1 -Methylquinarinium iodide, quinalidine red, thiazole orange, 1,1'-diethyl-2,2'-cyanine iodide, 1,1'-diethyl-2,4'-cyanine iodide, 1,1 '-Diethyl-4,4'-cyanine iodide, pinacyanol chloride, pinacyanol bromide, 1,1'-diethyl-2,2'-carbocyanine iodide, 1,1'-diethyl-4,4 ' -Carbocyanine iodide, 1,1'-diethyl-2,2'-dicarbocyanine iodide, 1,1'-diethyl-4 4'-dicarbocyanine iodide, Astrazone Orange G, 1,1 ', 3,3,3', 3'-hexamethylindodicarbocyanine, new indocyanine green, 5-cyano-2- {3- (5-Cyano-1,3-diethyl-1,3-dihydro-2H-benzimidazol-2-ylidene) -1-propenyl} -ethyl-3- (4-sulfobutyl) -1H-benzimidazolium hydroxide inner Salt, 3,3′-dimethyloxacarbocyanine iodide 449, 3,3′-diethyloxacarbocyanine iodide, 3,3′-dipropyloxacarbocyanine iodide, 3,3′-dihexyloxacarbocyanine iodide Dye, 5-phenyl-2-{-2- (5-phenyl-3- (3-sulfopropyl) -2 (3H -Benzoxazolylidene) methyl} 1-butenyl) -3- (3-sulfopropyl) -benzoxazolium hydroxide inner salt sodium salt, 5-phenyl-2-{-2- (5-phenyl-3) -(4-sulfobutyl) -2 (3H) -benzoxazolylidene) methyl} 1-butenyl) -3- (4-sulfobutyl) -benzoxazolium hydroxide inner salt sodium salt, 3,3′-diethyloxa Dicarbocyanine iodide, 5-chloro-9-ethyl-5′-phenyl-3,3′-bis (sulfopropyl) oxacarbocyanine hydroxide inner salt sodium salt, 3,3′-diethylthiocyanine iodide, 3,3′-diethylthiacarbocyanine iodide, 3,3′-dipropylthiacarbocyanine Iodide, 3,3′-diethyl-9-methylthiacarbocyanine iodide, ethylbenzothiazolidelidenemethylpropenylsulfoxybutylbenzothiazolium, 2- {2- (3- (carboxymethyl) -5-methyl -2 (3H) -benzothiazolylidenemethyl) -1-butenyl} -3-ethyl-5-methylbenzothiazolium hydroxide inner salt, 3,3′-diethylthiadicarbocyanine iodide, 3,3 '-Dipropylthiadicarbocyanine iodide, 5-(-3-sulfopropyl) -2- {3- (3-sulfopropyl) -2 (3H) -benzothiazolylidene} methyl) naphtho (1 , 2-Dithiazolium hydroxide inner salt triethylammonium salt, ethylmethylbenzothiazolidenemethyl Te Nils Gandolfo propyl naphthothiazolium helium, and the like.

Further, as compounds that can be decolored and discolored by other bases, compounds described in JP-A-2-166450, page 5, upper right, line 8 to page 6, upper left, first line, specifically, the following spectral increase Examples include dyes.
The spectral sensitizing dye is a compound that is decolored by the action of a base, and triarylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds, spirolane compounds and the like are acidic compounds such as hydrochloric acid, sulfuric acid, Inorganic acids such as phosphoric acid, bromic acid, hydrogen iodide, perchloric acid, acetic acid, alkylsulfonic acid, alkylbenzenesulfonic acid, naphthalenesulfonic acid, perfluoroalkylsulfonic acid, phenolic compound or salicylic acid derivative and polyvalent metal thereof Examples thereof include compounds developed with salt or the like.

Specifically, for example, a dye obtained by coloring the following compounds can be used. Examples thereof include those described in JP-A-55-227253. Specifically, for example, as a triarylmethane compound, 3,3-bis (p-dimethylaminophenyl) -6-dimethylamino is used. Phthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,3dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) ) -3- (2-methylindol-3-yl) phthalide, 3,3-bis (1-octyl-2-methylindol-3-yl) phthalide, and the like. Examples of the diphenylmethane compound include 4,4′-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl-leucooramine, N-2,4,5-trichlorophenylleucooramine, and the like. Examples of the compounds include rhodamine-5-anilinolactam, rhodamine-6- (p-nitroanilino) lactam, 2- (dibenzylamino) -6-diethylaminofluorane, 2-anilino-3-methyl-6-diethylaminofluorane. 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-6-N-methyl -N-cyclohexylaminofluorane, 2-anilino-3-chloro-6-die Tylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isobutylaminofluorane, 2-anilino-dibutylaminofluorane, 2-anilino-3-methyl-6-N-methyl-N- Tetrahydrofurfurylaminofluorane, 2-anilino-3-methyl-6-piperidinoaminofluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2- (3,4-dichloroanilino) -6 And diethylaminofluorane. Examples of the thiazine-based compound include benzoid meleucomethylene blue and p-nitrobenzoylleucomethylene blue. Examples of spiro compounds include 3-methyl-spiro-diα-naphthopyran, 3-ethyl-spiro-diα-naphthopyran, 3,3′-dichloro-spiro-diα-naphthopyran, 3-benzyl-spiro-diα-naphthopyran, 3 -Methyl-spiro-α-naphtho- (3-methoxy-α-benzo) pyran, 3-propyl-spiro-dibenzopyran and the like.
On the other hand, as the compound that develops color with a base, a base color-developing dye having a function of developing color by the action of a base is preferred, particularly preferably a (thio) lactone or sulfolactone skeleton in the structure, and a pH of 3 or more, particularly preferably In the hydrogen ion concentration region of pH 5 or higher, a dye that develops color by opening a (thio) lactone or sulfolactone skeleton in the dye may be used. Specific examples include compounds described in JP-A-11-143076, [0021] to [0029].

  In the present invention, the blending ratio of the base discoloring agent is preferably 0.01 to 100 parts by weight with respect to 100 parts by weight of the base generator, from the viewpoint of visibility of the exposed part, and is preferably 0.1 to 10 parts by weight. It is more preferable to use parts.

  In the present invention, the components (A) to (C) may be contained in the image forming layer, or may be contained in a layer different from the image forming layer such as an overcoat layer described later. When the components (A) to (C) are contained in a layer different from the image forming layer in the lithographic printing plate precursor, an overcoat layer is particularly preferable. Further, the above components can be contained in both the image forming layer and the overcoat layer.

[Elements for forming printed images]
The image forming layer or other layer preferably contains an element for forming a printed image as described above, and (a) an image forming element utilizing radical polymerization, and ( b) At least one of image forming elements utilizing thermal fusion or thermal reaction of the hydrophobized precursor can be used. When the element (a) is used, a radical polymerization type image forming layer is formed, and when the element (b) is used, a hydrophobic precursor system image forming layer is formed. Hereinafter, these elements will be described with reference to other components added when each element is used.

(A) Image forming element utilizing radical polymerization Since the radical polymerization type element has high image formation sensitivity, it is possible to effectively distribute exposure energy to printout image formation, and to produce a printout image with good visibility. It is suitable to obtain.
The radical polymerization element includes a radical polymerizable compound and a radical polymerization initiator as basic components.

<Radically polymerizable compound>
The radically polymerizable compound (hereinafter also simply referred to as a polymerizable compound) that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one ethylenically unsaturated bond. It is selected from compounds having, preferably two or more. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. In the present specification, the “radical polymerizable compound” includes not only a monomer but also a prepolymer, that is, a dimer, a trimer and an oligomer, a mixture thereof, a copolymer thereof, and the like. means. 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 monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  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 excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-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 to 308 (1984), which 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 portion, that is, the cured film, those having three or more functionalities are preferable, and further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrene 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 forming 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 the protective 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, based on the total solid content of the layer to be added. 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.

<Radical polymerization initiator>
The radical 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. As the radical polymerization initiator that can be used in the present invention, a known thermal polymerization initiator, a compound having a bond having a small bond dissociation energy, a photopolymerization initiator, and a known photooxidizer or bake-out agent are known. A radical generator can be mentioned. Among these, the radical polymerization initiator suitably used in the present invention is a compound that generates radicals by thermal energy.
Hereinafter, although the radical polymerization initiator used by this invention is demonstrated more concretely, this radical polymerization initiator can be used individually or in combination of 2 or more types.

Examples of such radical polymerization initiators include organic halogen compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oxime ester compounds. And 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, -(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-pheni Thio-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-. No. 131837, JP 2002-107916 A, JP 2764769 A, JP 2002-116539 A, and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, etc. Organoboron salts described in JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, and organic boron oxosulfonium complexes, No. 175554, JP-A-6-175553 The organoboron iodonium complex described in JP-A-9-188710, the organoboron phosphonium complex described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-5-140589 Examples thereof include organoboron transition metal coordination complexes such as 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. 13, 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 al, J.A. 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 suitably used in the present invention are represented by the following general formulas (RI-I) to (RI-III)
It is an onium salt represented by.

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 the 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 ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group having a carbon number of 20 or less, an alkyl group, an alkenyl group or an alkynyl group, 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, C1-C12 aryloxy group, halogen atom, C1-C12 alkylamino group, C1-C12
A dialkylamino group having 1 to 12 carbon atoms, an amide group having 1 to 12 carbon atoms or an arylamide group, a carbonyl group, a 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. It is done. 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 onium salts represented by the above formulas (RI-I) to (RI-III) are shown below, but the present invention is not limited thereto.

  These radical polymerization initiators are added in a proportion of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total solid content constituting the layer to be added. can do. Within this range, the printing durability is further improved. These radical polymerization initiators may be used alone or in combination of two or more. Further, these radical polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto.

<Other image forming layer components>
The image forming layer of the present invention may contain the above components (A) to (C), but in addition, a binder polymer, a surfactant, a colorant, a polymerization inhibitor, a higher fatty acid derivative, a plasticizer, Additives such as inorganic fine particles and low molecular weight hydrophilic compounds can be contained as required. These will be described below.

<Binder polymer>
The image forming layer 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 ethylene. Examples thereof include polymers having a polymerizable 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, or an alkyl group having 1 to 20 carbon atoms, an aryl group, and alkoxy. R ¹ and R ² or R ³ may be bonded to each other to form a ring, n represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. Represents a group).

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.

  The binder polymer having crosslinkability, for example, has a free radical (polymerization initiation radical or a growth radical in the polymerization process of the polymerizable compound) added to the crosslinkable functional group, and the polymerization chain of the polymerizable compound is formed directly between the 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 together, thereby causing cross-linking between polymer molecules. Forms and cures.

  The content of the crosslinkable group in the binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1.0, 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 solubility or dispersibility in ink, the binder polymer is preferably oleophilic, and in order to improve solubility or dispersibility in dampening water, the binder polymer is hydrophilic. Is preferred. Therefore, 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, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl methacrylate homopolymers Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate, polyethylene glycol , 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 Methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, 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 radical polymerization initiator used for 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 10 to 90% by mass, preferably 20 to 80% by mass, and more preferably 30 to 70% by mass with respect to the total solid content of the image forming layer. 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 forming 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 alcohol 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 forming layer.

<Colorant>
In the present invention, various compounds other than these may be added as necessary. For example, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in No. 293247. In addition, pigments such as phthalocyanine pigments, azo pigments, carbon black, and titanium oxide can also be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is 0.01 to 10% by mass with respect to the total solid content of the image forming layer.

<Polymerization inhibitor>
A small amount of a thermal polymerization inhibitor is preferably added to the image forming layer in order to prevent unnecessary thermal polymerization of the (C) radical polymerizable monomer during the production or storage of the image forming layer.
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 forming layer.

<Higher fatty acid derivatives, etc.>
In order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenic acid amide are added to the image forming layer so that it is unevenly distributed on the surface of the image forming layer in the drying process after coating. May be. 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 forming layer.

<Plasticizer>
The image forming layer may contain a plasticizer in order to improve 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 forming layer.

<Inorganic fine particles>
The image forming layer may contain inorganic fine particles for 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 is preferably exemplified. 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 excellent in hydrophilicity that is stably dispersed in the image forming layer, sufficiently retains the film strength of the image forming 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 forming layer.

<Low molecular hydrophilic compound>
The image forming layer 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 radical polymerization type image forming layer>
In the present invention, several modes can be used as a method of incorporating the above-mentioned image forming layer constituents into the image forming layer. One is, for example, an embodiment in which the constituent components are dissolved and applied in an appropriate solvent as described in JP-A-2002-287334, and the other is, for example, JP-A-2001-277740, As described in Japanese Patent Application Laid-Open No. 2001-277742, this is an embodiment (microcapsule type image forming layer) in which the constituent components of the image forming layer are encapsulated in microcapsules and contained in the image forming layer. Further, in the microcapsule type image forming layer, the constituent component may be contained outside the microcapsule. In the microcapsule type image forming layer, it is a more preferable embodiment that a hydrophobic constituent component is encapsulated in the microcapsule and a hydrophilic constituent component is contained outside the microcapsule.
Among the components of the image forming layer, the microencapsulation of the infrared absorber, the base generator and the base discoloring agent reacts with each other by separating the print-out image formation reaction system and the print image formation reaction system. Since inhibition is avoided, this is a more preferable embodiment for obtaining a good printout image and good printing durability.

  As a method for microencapsulating the above-mentioned image forming layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by precipitation of polymer, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcinol A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin, hydroxycellulose, etc. found in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method by monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807, 967074, etc. However, 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 the binder polymer may be introduced into the microcapsule wall.

  The average particle size of the microcapsules 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 forming layer is coated by preparing a coating solution by dispersing or dissolving the necessary components 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 forming layer may 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 repeating a plurality of coating and drying operations.

The coating amount (solid content) of the image forming 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) Image forming element of hydrophobized precursor system <Hydrophobicized precursor>
In the present invention, the hydrophobized precursor is a fine particle capable of converting a hydrophilic image forming 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 which included the compound which has a thermoreactive group may be sufficient.

  As thermoplastic polymer fine particles used in the image forming layer, Research Disclosure No. 33303 of January 1992, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9- Preferred examples include thermoplastic polymer fine particles described in JP-A No. 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, a urea derivative such as urea or methoxymethylated urea formed by resination 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.), cationically 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 (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 Examples of suitable acid anhydrides and reaction partners are amino groups or hydroxyl groups. Kill.

  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, it is preferable to carry out emulsion polymerization or suspension polymerization of the monomer having the above functional group. 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 thereof, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2- Hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid, maleic anhydride, bifunctional acrylate, 2 officers Methacrylate, and the like, but not limited thereto.

  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 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 mentioned. Below, the compound which has a thermoreactive group is demonstrated.

  As the compound having a radical polymerizable unsaturated group, the same compounds as those shown as the radical polymerization type microcapsules 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 obtained by reaction of a polyhydric alcohol or a polyhydric phenol with epichlorohydrin or a prepolymer thereof. 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, novolak tree Etc. glycidyl ethers, furthermore, 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), Epikote 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. Suitable acid anhydrides for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  Microencapsulation of the above-mentioned compound having a thermoreactive group can be carried out by the known method described above in the explanation of the radical polymerization system.

<Other image forming layer components>
The image forming layer can contain a hydrophilic resin in order to improve the on-press developability and the film strength of the image forming 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 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, hydroxypropyl acrylate Homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers, Homopolymers and copolymers of butyl 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, polyvinylpyrrolidone, acrylamide Homopolymers and copolymers, methacrylamide homopolymers and copolymers, N-methylolacrylamide homopolymers and copolymers, 2-acrylamido-2-methyl-1-propanesulfonic acid homopolymers and copolymers, 2-methacryloyloxyethylphosphonic acid And homopolymers and copolymers thereof.

  The amount of the hydrophilic resin added to the image forming 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 aldehydes such as glyoxal, 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 can be used in combination.

  The image forming layer may contain a reaction accelerator that initiates or accelerates the reaction of the thermal reactive group. As such a reaction accelerator, the above radical polymerization initiator can be mentioned as a suitable one.

  Two or more kinds of the reaction accelerators can be used in combination. The reaction accelerator may be added directly to the image forming layer coating solution or may be added in the form of polymer fine particles. The content of the reaction accelerator in the image forming layer is preferably from 0.01 to 20% by mass, more preferably from 0.1 to 10% by mass, based on the total solid content of the image forming 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 forming layer matrix in the above-described hydrophobized precursor system image forming layer. 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 hydrophobic precursor system image-forming layer includes a surfactant, a colorant, a polymerization inhibitor, a higher fatty acid derivative, and a plasticizer described in <Other image-forming layer components> of the polymerized image-forming layer. In addition, additives such as inorganic fine particles and low molecular weight hydrophilic compounds can be contained as necessary.

<Formation of image forming layer of hydrophobized precursor system>
As in the case of the radical polymerization image-forming layer, the hydrophobic precursor system image-forming layer is prepared by coating or drying on a support by preparing a coating solution in which each of the necessary components is dispersed or dissolved in a solvent. Formed.

The coating amount (solid content) of the image forming layer 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 forming 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 forming 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 lithographic printing plate precursors of molds.

  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, the affinity with the hydrophilic component in the emulsion ink is improved, and the film strength of the image forming layer itself is also 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 salts thereof, 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 Methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene Glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a degree of hydrolysis of at least 60 mol%, preferably at least 80 mol% Methacrylamide homopolymers and polymers, N-methylolacrylamide homopolymers and copolymers, and the like.

  When the above hydrophilic resin is used for the image forming layer according to the present invention, the hydrophilic resin may be used after being crosslinked. As the cross-linking agent used for forming the cross-linked structure, those described above are used.

  Further, as a preferred embodiment of the non-processing (non-development) type image forming 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 crosslinked 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 binding 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 them, 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 for the image forming layer, a coating solution which is a sol containing at least one compound having a silanol group is 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 siloxane skeleton structure.

  In addition, the image forming 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 (V), and the silane compound having at least one silanol group is represented by the following general formula (VI). In addition, the substance system added to the image forming layer does not necessarily need to be a silane compound of the general formula (VI) 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 (VI). There may be a mixture of.

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

Formula (VI) (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 are substituted with halogen atom (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-bromoethyl Til group, 2- (2-methoxyethyl) oxyethyl group, 2-methoxycarbonylethyl group, 3-carboxyethyl group, 3-carboxypropyl group, benzyl group and the like),

—OCOR ″ group (R ″ represents the same content as R ′), —COOR ″ group, —COR ″ group, —N (R ′ ″) (R ′ ″) group ( R ′ ″ represents a hydrogen atom or 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. A plurality of these substituents may be substituted in the alkyl group. A linear or branched alkenyl group having 2 to 12 carbon atoms (for example, vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, octenyl group, decenyl group, dodecenyl group, etc .; Examples of the group substituted by the group include those having the same content as the group substituted by the alkyl group, and an aralkyl group having 7 to 14 carbon atoms which may be substituted (for example, benzyl group, phenethyl group, 3 -Phenylpropyl group, naphthylmethyl group, 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 of them may be substituted. ), An alicyclic group having 5 to 10 carbon atoms which may be substituted (for example, cyclopentyl group, cyclohexyl group, 2-cyclohexylethyl group, norbornyl group, adama) A til group, etc .; examples of the group substituted by these include those having the same contents as the group substituted by the alkyl group, and may be substituted in plural. A good aryl group (for example, a phenyl group, a naphthyl group, and the substituent includes the same content as the group substituted by the alkyl group, or a plurality of substituents may be substituted), or a nitrogen atom, Heterocyclic group which may be condensed, containing at least one atom selected from oxygen atom and sulfur atom (for example, pyran ring, furan ring, thiophene ring, morpholine ring, pyrrole ring, thiazole ring, oxazole ring, pyridine) Ring, piperidine ring, pyrrolidone ring, benzothiazole ring, benzoxazole ring, quinoline ring, tetrahydrofuran ring, etc., which may contain a substituent. Serial can be mentioned those having the same content as groups substituted with an alkyl group, or may be a plurality substituted) it represents.

As the substituent of the —OR ¹ group, —OCOR ² group or —N (R ³ ) (R ⁴ ) group of Y in the general formula (VI), for example, the following substituents are represented. 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 content 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 (VI) 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-methacryloxyxypropyltri Methoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, β- (3,4- (Epoxycyclohexyl) ethyltrimethoxysilane and the like.

In the image forming layer, together with the silane compound of the general formula (VI), a metal compound capable of forming a film by bonding to a resin at the time of sol-gel conversion such as Ti, Zn, Sn, Zr, and Al may be used in combination. it can. 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. R ″ represents a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group.

  Furthermore, in order to accelerate the hydrolysis and polycondensation reaction of the compound represented by the general formula (VI) 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 forming layer using the sol-gel method described above is particularly preferable as the configuration of the image forming layer according to the present invention. For further details of 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 forming 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 forming layer.

  In addition, the thickness of the image forming layer is preferably 0.1 to 10 μm from the viewpoint of printing durability, and more preferably 0.5 to 5 μm.

[Hydrophilic support]
The hydrophilic support (hereinafter also simply referred to as “support”) used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate. 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. A preferable support includes a polyester film and an aluminum plate. Among them, 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 foreign 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 a roughening treatment or hydrophilic film formation. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the image forming 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 (electrochemical surface roughening treatment that dissolves the surface), 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 aluminum plate that has been subjected to the surface roughening treatment and other treatments as necessary is subjected to a treatment for providing a hydrophilic film having a low thermal conductivity. The hydrophilic film has a thermal conductivity in the film thickness direction of 0.05 W / mK or more, preferably 0.08 W / mK or more, and 0.5 W / mK or less, preferably 0.3 W / m. mK or less, more preferably 0.2 W / mK or less. When the thermal conductivity in the film thickness direction is 0.05 to 0.5 W / mK, it is possible to suppress the diffusion of heat generated in the image forming layer due to laser light exposure to the support. As a result, when the lithographic printing plate precursor according to the present invention is used as an on-press development type or an unprocessed type, the heat generated by laser exposure can be effectively used, so that the sensitivity is increased and sufficient image formation and printing are performed. It is possible to form an output image.

  Hereinafter, the thermal conductivity in the film thickness direction of the hydrophilic film defined in the present invention will be described. Various methods have been reported so far for measuring the thermal conductivity of thin films. In 1986, ONO et al. Reported the thermal conductivity in the planar direction of the thin film using a thermograph. Attempts have also been made to apply an AC heating method to the measurement of thermophysical properties of thin films. The origin of the AC heating method can be traced back to the report of 1863, but in recent years, various measurement methods have been proposed by combining a heating method using a laser and a Fourier transform. Devices using the laser angstrom method are actually commercially available. All of these methods determine the thermal conductivity in the plane direction (in-plane direction) of the thin film.

However, when considering the thermal conduction of thin films, thermal diffusion in the depth direction is rather an important factor. As reported variously, it is said that the thermal conductivity of the thin film is not isotropic, and it is extremely important to directly measure the thermal conductivity in the film thickness direction particularly in the case of the present invention. From this point of view, a method using a thermocomparator as an attempt to measure the thermophysical properties in the film thickness direction of a thin film is described in a paper by Lambropoulos et al. (J. Appl. Phys., 66 (9) (1 November 1989)) and Hengager et al. (APPLIED OPTICS, Vol. 32, No. 1 (1 January 1993)). Furthermore, in recent years, a method of measuring the thermal diffusivity of a polymer thin film by temperature wave thermal analysis applying Fourier analysis has been reported by Hashimoto et al. (Net Sukutei, 27 (3) (
2000)).

  The thermal conductivity in the film thickness direction of the hydrophilic film defined in the present invention is measured by the method using the thermo-comparator. Hereinafter, the method will be described in detail. The basic principle of the method is described in detail in the above-mentioned Lambropoulos et al. Paper and Henger et al. Paper. In the present invention, the measurement was performed by the method described in the publication using a thermo-comparator shown in FIG. 3 of JP-A-2003-103951.

  The relationship between each temperature and the thermal conductivity of the film is expressed by the following formula (1).

However, the code | symbol in said Formula (1) is as follows.
T _t : tip temperature, T _b : heat sink temperature, T _r : reservoir temperature, K _tf : film thermal conductivity, K ₁ : reservoir thermal conductivity, K ₂ : chip thermal conductivity (400 W for oxygen-free copper) / MK), K ₄ : metal substrate thermal conductivity (when no film is provided), r ₁ : tip tip radius of curvature, A ₂ : contact area between reservoir and chip, A ₃ : contact area between chip and film , T: film thickness, t ₂ : contact thickness (≈0)

By measuring and plotting each temperature (T _t , T _b and T _r ) while changing the film thickness (t), the slope of the above equation (1) is obtained, and the film thermal conductivity (K _tf ) is obtained. Can do. That is, as is apparent from the above equation (1), this inclination is the reservoir thermal conductivity (K ₁ ), the tip radius of curvature (r ₁ ), the film thermal conductivity (K _tf ), and the contact between the chip and the film. Since it is a value determined by the area (A ₃ ) and K ₁ , r ₁ and A ₃ are known values, the value of K _tf can be obtained from the slope.

The present inventors determined the thermal conductivity of the hydrophilic film (anodized film Al ₂ O ₃ ) provided on the aluminum substrate using the above measurement method. The temperature was measured while changing the film thickness, and the thermal conductivity of Al ₂ O ₃ determined from the slope of the graph was 0.69 W / mK. This is in good agreement with the results of Lambropoulos et al. This result also shows that the thermophysical value of the thin film is different from the bulk thermophysical value (the thermal conductivity of bulk Al ₂ O ₃ is 28 W / mK).

  When the above method is used to measure the thermal conductivity in the film thickness direction of the hydrophilic film of the lithographic printing plate precursor according to the present invention, the tip end is made minute and the lithographic printing plate is kept constant by keeping the pressing load constant. For the surface roughened for the purpose, it is preferable because a result without variation can be obtained. The value of thermal conductivity is preferably measured at a plurality of different points on the sample, for example, 5 points, and obtained as an average value.

  The film thickness of the hydrophilic film is preferably 0.1 μm or more, more preferably 0.3 μm or more, particularly 0.6 μm or more in terms of scratch resistance and printing durability. Preferably, from the viewpoint of manufacturing cost, in view of the fact that a great amount of energy is required to provide a thick film, it is preferably 5 μm or less, more preferably 3 μm or less, and 2 μm or less. Is particularly preferred.

The hydrophilic film preferably has a density of 1000 to 3200 kg / m ³ from the viewpoint of the effect on heat insulation, the film strength, and the difficulty of smearing during printing.

  As the density measurement method, for example, it is calculated by the following formula from the mass measurement by the Mason method (anodized film mass method by dissolution of chromic acid / phosphoric acid mixed solution) and the film thickness obtained by observing the cross section with SEM. can do.

Density (kg / m ³ ) = (Hydrophilic film mass / film thickness per unit area)

  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 them, 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 in general. In general, 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 0.05 to 0.5 W / mK. 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 set to 0.05 to 0.5 W / mK. 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 set to 0.05 to 0.5 W / mK.

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 dissolution amount of the anodized film is preferably 0.01 to 20 g / m ² , more preferably 0.1 to 0.1 g.
5 g / m ^2, particularly preferably at a range of a 0.2~4g / m ^2.

  When using an acid aqueous solution for 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 excessively enlarged, 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, and more preferably 10 nm. 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 the 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 step and phosphoric acid is used in the second step. Moreover, you may perform the below-mentioned sealing process to the support body 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 above-described anodized film. Examples of the compound constituting the inorganic film include oxides, nitrides, silicides, borides, and carbides. Moreover, the inorganic film may be comprised only from the compound single-piece | unit, and may be comprised by the mixture of the compound. 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 hydrophilic support obtained by providing the 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. When the water vapor sealing process is performed, the sealing treatment film is formed from the top of the pore. The formation of the pore-treated film is different. In addition, there are immersion treatment with a solution, spray treatment, coating treatment, vapor deposition treatment, sputtering, ion plating, thermal spraying, plating, etc., but there is no particular limitation. Among them, particularly preferable is a sealing treatment using particles having an average particle diameter of 8 to 800 nm described in JP-A No. 2002-214764.

  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 is obtained, and sufficient adhesion with the image forming layer is obtained, so Excellent in properties. The thickness of the particle layer is preferably 8 to 800 nm, and more preferably 10 to 500 nm.

  The particles used in the present invention preferably have a thermal conductivity of 60 W / mK or less, more preferably 40 W / mK or less, and particularly preferably 0.3 to 10 W / mK or less. When the thermal conductivity is 60 W / mK or less, the thermal diffusion to the aluminum substrate is sufficiently suppressed, and the effect of increasing the sensitivity is sufficiently obtained.

  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. In addition, the frequency of the alternating current is preferably 30 to 200 Hz, 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. In order to charge the electrolyte positively or negatively, the pH of the electrolytic solution can be adjusted, for example, by adding sulfuric acid. The electrolytic treatment is performed, for example, using direct current, using an aluminum plate as a cathode, using the above electrolytic solution, and using 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 was 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 comprising 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 acids such as methylenediphosphonic acid and ethylenediphosphonic acid; organic phosphoric esters such as phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid which may have a substituent; Organic phosphinic acids such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid; amino acids such as glycine and β-alanine; hydrochlorides of amines having a hydroxy group 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. Among 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 for treating a backcoat material by coating, treatment of phosphonic acids described in JP-A-6-262872, and JP-A-6-297875. The coating treatment described in the gazette, the anodizing method described in JP-A-10-109480, the immersion treatment method described in JP-A-2000-81704 and JP-A-2000-89466 Any method 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.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the image forming 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]
A back coat can be provided on the back surface of the support, if necessary, after surface treatment or after forming an undercoat layer on the support.
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 forming 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. Further, in the unexposed portion, the image forming 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. Preferred examples include phosphorus compounds having an ethylenic double bond reactive group described in the publication.
The coating amount (solid content) of the undercoat layer is preferably from 0.1 to 100 mg / m ² , and more preferably from ¹ to 30 mg / m ² .

[Protective layer (overcoat layer)]
In the lithographic printing plate precursor according to the present invention, a protective layer is provided on the image forming layer as necessary in order to prevent the occurrence of scratches in the image forming 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 atmosphere, but the protective layer is an image of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that inhibit the image forming reaction caused by exposure in the image forming layer. It prevents the formation layer from being mixed and prevents the inhibition of the image forming reaction due to exposure in the atmosphere. Therefore, the properties desired for the protective layer are low permeability of low-molecular compounds such as oxygen, furthermore, good transparency of light used for exposure, excellent adhesion with the image forming 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-A-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, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA manufactured by Kuraray Co., Ltd. -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.

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. In general, the higher the hydrolysis rate of PVA (that is, the higher the content of unsubstituted vinyl alcohol units in the protective layer), the higher 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. Accordingly, the oxygen permeability A at 25 ° C. and 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 based on (co) polymers 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 forming layer when the image forming layer is oleophilic, the protective layer is easily peeled off due to insufficient adhesive force. 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 forming layer and the protective layer. For example, in JP-A-49-70702 and British Patent Application No. 1303578, a hydrophilic polymer mainly composed of polyvinyl alcohol, an acrylic emulsion, a water-insoluble vinylpyrrolidone-vinyl acetate copolymer, etc. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on an image forming 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-A-55-49729.

In the present invention, the above-mentioned print-out image forming component (a compound causing a color change by the action of radicals, a radical polymerization initiator, an infrared absorber) can be contained in the protective layer. A mode in which these print-out image forming components are added to the protective layer instead of the image-forming layer is preferable because the print-out image forming reaction is separated from the polymerization reaction system in the image forming layer and inhibition of the mutual reaction can be avoided. It is also a preferred embodiment that these print-out image forming components are contained in the protective layer in the form of being encapsulated in microcapsules. In the case of enhancing the printout image, the printout image forming component can be contained in both the protective layer and the image forming layer.
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, it is safe light without causing a decrease in sensitivity. Suitability can be improved.

〔exposure〕
The lithographic printing plate precursor according to the invention is used after imagewise exposure with an infrared laser.
Although the infrared laser used in this case is not particularly limited, a solid-state laser and a semiconductor laser that emit infrared rays having a wavelength of 760 to 1200 nm are preferable. 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 can be printed by supplying an oil-based ink and an aqueous component without any development processing steps after imagewise exposure with an infrared laser.
Specifically, after exposing the lithographic printing plate precursor with an infrared laser, mounting it on a printing machine without passing through the development process, printing the lithographic printing plate precursor on the printing machine, Examples include a method of printing with an infrared laser 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 exposed to the image after the lithographic printing plate precursor is exposed imagewise with an infrared laser, and without undergoing a development processing step such as a wet development processing step. When ink is supplied and printing is performed, in the exposed portion of the image forming layer, the image forming 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 forming 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 forming layer in the exposed area, and printing is started. Here, the water-based component or the 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 unexposed image forming layer. 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.
Further, the exposed portion is excellent in visibility since the base discoloring agent changes color.
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.
[Example 1]
(Preparation of hydrophilic support)
Using an aluminum plate according to JIS-A-1050 having a thickness of 0.3 mm, the following steps (a) to (k) were performed in this order.
(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to a surface of an aluminum plate, it is mechanically rotated by a roller-like nylon brush. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (Φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The obtained aluminum plate was sprayed with an aqueous NaOH solution (concentration: 26 mass%, aluminum ion concentration: 6.5 mass%) at a temperature of 70 ° C. to dissolve the aluminum plate by 6 g / m ^2. did. Thereafter, washing with water was performed using well water.
(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.
(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 0.8 ms until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode. Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water. The etching amount was 3.5 g / m ² .
(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. Thereafter, washing with water was performed using well water.
(H) Alkaline etching treatment An aluminum plate is etched by spraying at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, and the aluminum plate is dissolved at 0.10 g / m ² , so The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.
(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water. Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .
(K) Alkali metal silicate treatment An alkali metal silicate treatment (silicate treatment) was performed by immersing the obtained aluminum plate in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds. ) Then, the aluminum support body was produced by performing the water washing by the spray using well water. The amount of silicate adhering at that time was 3.6 mg / m ² .

(Formation of photosensitive image forming layer)
On the obtained support, an image forming layer coating liquid (1) having the following composition was applied with a wire bar and dried at 80 ° C. for 60 seconds to form an image forming layer. The coating amount was 1.0 g / m ² .
<Image forming layer coating solution (1) composition>
2 parts by mass of the following infrared absorber (D-1) 10 parts by mass of the following radical polymerization initiator (I-1) 55 parts by mass of dipentaerythritol hexaacrylate (NK ester A-DPH, manufactured by Shin-Nakamura Chemical Co., Ltd.) )
37 parts by weight of the following binder polymer (B-1) 10 parts by weight of the following base discoloring agent (C-1) 10 parts by weight of the following base generator (A-1) The following fluorosurfactant (W-1) 6 parts by weight Methyl ethyl ketone 900 parts by weight

(Evaluation of lithographic printing plate precursor)
The resulting lithographic printing plate precursor was image-exposed with a test pattern (Trendsetter 3244VX, Creo) at a beam intensity of 10.2 W and a drum rotation speed of 150 rpm. The contrast between the unexposed area and the exposed area, that is, the visibility of the image (visibility) was visually evaluated. Without developing this plate, it was mounted on a cylinder of a printing machine (SPRINT S26, manufactured by Komori Corporation), and diluted 4% with a commercial fountain solution (IF-102, manufactured by Fuji Photo Film Co., Ltd.). The liquid was supplied as dampening water, then black ink (Values-G (black), manufactured by Dainippon Ink & Chemicals, Inc.) was supplied, and paper was further supplied for printing. The number of papers (on-press developability) required to obtain a good printed matter and the number of papers (print durability) that could be printed without causing smearing or blurring were evaluated. The results are shown in Table 1.

[Example 2]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the base color changing agent (C-2) was used instead of the base color changing agent (C-1). The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the base generator (A-2) was used in place of the base generator (A-1). The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
(Preparation of microcapsule dispersion (1))
16.5 parts by mass of ethyl acetate and a 1: 3 (molar ratio) adduct of trimethylolpropane and xylylene diisocyanate (Takenate D-110N, manufactured by Mitsui Takeda Chemical Co., Ltd., containing 25% by mass of ethyl acetate) 10 Parts by weight, 3 parts by weight of a base discoloring agent (C-1), 0.6 parts by weight of the following infrared absorber (D-3), 1 part by weight of a base generator (A-2), tricresyl phosphate 1.5 An oil phase was obtained by dissolving and dispersing parts by mass and 0.1 part by mass of an anionic surfactant (Pionin P-A41C, Takemoto Yushi Co., Ltd.).
Separately, 37.5 parts by mass of a 4% by mass aqueous solution of polyvinyl alcohol (PVA205, manufactured by Kuraray Co., Ltd.) was prepared as an aqueous phase.
The oil phase and the aqueous phase were mixed and emulsified with a homogenizer at 12000 rpm for 10 minutes under water cooling. 24.5 parts by mass of water was added to the emulsion, followed by stirring at room temperature for 30 minutes and further at 40 ° C. for 3 hours. Thereafter, pure water was added so that the solid content concentration of the dispersion became 15% by mass to prepare a microcapsule dispersion (1). The average particle size of the microcapsules was 0.30 μm.

(Formation of photosensitive image forming layer)
On the support prepared in Example 1, first, an image forming layer coating solution (3) having the following composition was applied with a wire bar and dried at 80 ° C. for 60 seconds to form a photosensitive image forming layer. The coating amount was 1.0 g / m ² .

Image forming layer coating liquid (3) Composition 2 parts by weight of the above infrared absorber (D-1) 10 parts by weight of the above radical polymerization initiator (I-1) 55 parts by weight of dipentaerythritol hexaacrylate (NK ester A-DPH , Shin-Nakamura Chemical Co., Ltd.)
37 parts by mass of the above binder polymer (B-1) 1 part by mass of the above fluorosurfactant (W-1) 900 parts by mass of methyl ethyl ketone

Next, a water-soluble overcoat layer coating solution (2) having the following composition was coated on the image forming layer (3) with a wire bar so that the coating amount after drying was 1.5 g / m ^2, and 90 ° C. at 90 ° C. The plate was dried for 2 seconds to prepare a lithographic printing plate precursor. The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 2.
Water-soluble overcoat layer coating solution (2) Composition polyvinyl alcohol (degree of saponification: 98 mol%, degree of polymerization: 500)
95 parts by mass Polyvinylpyrrolidone / vinyl acetate copolymer 4 parts by mass (Luvitec VA 64W, manufactured by BASF)
Nonionic surfactant (EMALEX710, manufactured by Nippon Emulsion Co., Ltd.) 1 part by weight Microcapsule dispersion (1) 1000 parts by weight Pure water 2150 parts by weight

[Example 5]
(Formation of photosensitive image forming layer)
On the support prepared in Example 1, first, the photosensitive image forming layer coating solution (3) having the above composition was applied with a wire bar and dried at 80 ° C. for 60 seconds to form a photosensitive image forming layer. . The coating amount was 1.0 g / m ² .
Next, a water-soluble overcoat layer coating solution (3) having the following composition was coated on the photosensitive image forming layer (3) with a wire bar so that the coating amount after drying was 1.5 g / m ² , 100 ° C. Was dried for 90 seconds to prepare a lithographic printing plate precursor. The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 2.
Water-soluble overcoat layer coating solution (3) Composition polyvinyl alcohol (degree of saponification: 98 mol%, degree of polymerization: 500)
95 parts by mass Polyvinylpyrrolidone / vinyl acetate copolymer 4 parts by mass (Luvitec VA 64W, manufactured by BASF)
Nonionic surfactant (EMALEX710, manufactured by Nippon Emulsion Co., Ltd.) 1 part by weight Base generator (A-2) 10 parts by weight Base discoloring agent (C-3) 10 parts by weight
2150 parts by mass of pure water

[Example 6]
A lithographic printing plate precursor was prepared in the same manner as in Example 5 except that the base generator (A-3) was used instead of the base generator (A-2). The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 7]
(Formation of photosensitive image forming layer)
On the support produced in Example 1, a photosensitive image forming layer coating solution (4) having the following composition was applied with a wire bar and dried at 80 ° C. for 60 seconds to form a photosensitive image forming layer. The coating amount was 1.0 g / m ² . The produced lithographic printing plate precursor was evaluated in the same manner as in Example 1. The results are shown in Table 3.
Image forming layer coating liquid (4) Composition 2 parts by weight of the above infrared absorber (D-1) 10 parts by weight of the above radical polymerization initiator (I-1) 40 parts by weight of dipentaerythritol hexaacrylate (NK ester A-DPH , Shin-Nakamura Chemical Co., Ltd.)
16 parts by mass of the above binder polymer (B-1) 300 parts by mass of the above microcapsule dispersion (1) 1 part by mass of the above fluorosurfactant (W-1) 100 parts by mass of methyl ethyl ketone 1-methoxy-2-propanol 850 parts by mass Pure water 200 parts by mass

  The structures of the base generators (A-1) to (A-3) and the base discoloring agents (C-1) to (C-3) used in the examples are shown below.

Claims (7)

  A lithographic printing plate precursor having at least an image-forming layer capable of recording an image by infrared laser exposure on a support, wherein at least one layer of the lithographic printing plate precursor comprises (A) an infrared absorber and (B) a base generation A lithographic printing plate precursor comprising an agent and (C) a base discoloring agent and having a color change between an exposed area and an unexposed area.   A layer containing (A) an infrared absorber, (B) a base generator, and (C) a base discoloring agent so as to cause a color change between an exposed area and an unexposed area, The lithographic printing plate precursor as claimed in claim 1, comprising a radically polymerizable compound and (E) a radical polymerization initiator.   An image forming layer is a layer containing (A) an infrared absorber, (B) a base generator, and (C) a base discoloring agent so that a color change occurs between an exposed portion and an unexposed portion. The planographic printing plate precursor according to claim 1 or 2.   A layer containing the support, the (A) infrared absorber, the (B) base generator, and the (C) base discoloring agent, and a color change between the exposed portion and the unexposed portion; A lithographic printing plate precursor as claimed in claim 1, wherein a layer containing (D) a radical polymerizable compound and (E) a radical polymerization initiator is provided between the two.   The lithographic printing plate according to claim 1, wherein the lithographic printing plate precursor is printable by being mounted on a printing machine without undergoing a development processing step after image recording by laser exposure, or by image recording after mounting of the printing machine. Original edition.   The lithographic printing plate precursor according to any one of claims 1 to 5 is mounted on a printing press and imagewise exposed with an infrared laser, or imagewise exposed with an infrared laser and then mounted on a printing press, A plate making method of a lithographic printing plate precursor, comprising supplying a printing ink and a fountain solution to the lithographic printing plate precursor to remove an infrared laser unexposed portion of the image forming layer.   The lithographic printing plate precursor according to any one of claims 1 to 5 is mounted on a printing press and imagewise exposed with an infrared laser, or imagewise exposed with an infrared laser and then mounted on a printing press, A lithographic printing method in which printing ink and fountain solution are supplied to a lithographic printing plate precursor to remove an infrared laser unexposed portion of the image forming layer for printing.