JP2001305724A - Method for producing planographic printing plate and planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a planographic printing plate in which a used leaching liquid is easily treated. SOLUTION: The planographic printing plate is produced by successively carrying out a step for bringing a planographic printing original plate with a planographic printing material layer comprising hydrophilic fine particles each having a crosslinkable surface on a hydrophobic base into an imagewise crosslinking reaction to chemically bond hydrophilic fine particles to one another and a step for removing unbonded hydrophilic fine particles to form a hydrophobic region comprising the disclosed surface of the base and a hydrophilic region comprising the chemically bonded hydrophilic fine particles in this order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate making method for making a lithographic printing plate in which a hydrophilic region and a hydrophobic region are formed in an image.

[0002]

2. Description of the Related Art Lithographic printing is a method of printing by utilizing the repulsion between oil (oil-based ink) and water (fountain solution). In lithographic printing, a lithographic printing plate in which a hydrophilic region and a hydrophobic region are formed in an image shape is used. As a material (plate material) for making a lithographic plate, a PS plate in which a hydrophobic photosensitive resin is coated on a support having a hydrophilic surface is generally used. There are two types of photosensitive resins, a photocurable type and a photodecomposable type. The unexposed portion of the photocurable photosensitive resin or the exposed portion of the photodecomposable photosensitive resin is removed to expose the hydrophilic surface of the support as a hydrophilic region. Then, the exposed portion of the remaining photocurable photosensitive resin or the unexposed portion of the photodecomposable photosensitive resin functions as a hydrophobic region. The unexposed part of the photocurable photosensitive resin or the exposed part of the photodecomposable photosensitive resin
Remove with an alkaline eluent (developer). Since the photosensitive resin is dissolved in the waste liquid of the eluate, it is difficult to reuse the eluate. Therefore, in the plate making (developing) process of the PS plate, a large amount of eluate is used, and the waste liquid is disposed.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of making a lithographic printing plate in which the waste liquid of the eluate can be easily treated. Another object of the present invention is to provide a lithographic printing plate having high ink receptivity and high printing durability.

[0004]

The object of the present invention has been attained by the following (1) to (5) lithographic printing plate making methods and the following (6) lithographic printing plate. (1) A lithographic printing plate precursor having a lithographic printing material layer composed of hydrophilic fine particles having a crosslinkable surface on a hydrophobic support is image-wise crosslinked to chemically bond the hydrophilic fine particles to each other. Removing the hydrophilic fine particles that have not been chemically bonded to form a hydrophobic region consisting of the exposed support surface and a hydrophilic region consisting of the chemically bonded hydrophilic fine particles. A method of making lithographic printing plates in order.

(2) The lithographic printing material layer or the photosensitive layer provided adjacent to the lithographic printing material layer contains silver halide, and after performing a step of imagewise exposing the lithographic printing original plate, the silver halide is developed using a developing agent. The plate-making method according to (1), wherein an oxidized form of the developer causes the cross-linkable surface of the hydrophilic fine particles to undergo an image-wise cross-linking reaction. (3) The plate making method according to (1), wherein a crosslinkable surface is formed on the hydrophilic fine particles by attaching or binding the epoxy compound to the surface of the hydrophilic fine particles. (4) The plate making method according to (1), wherein the hydrophilic fine particles are made of silica. (5) The plate making method according to (1), wherein the lithographic printing material layer further contains gelatin as a binder. (6) A relief image composed of chemically bonded hydrophilic fine particles is formed on a hydrophobic support, and the chemically bonded hydrophilic fine particles function as hydrophilic regions and are exposed. A lithographic printing plate, wherein the surface functions as a hydrophobic region.

[0006]

According to the present invention, the hydrophilic fine particles are chemically bonded to each other by carrying out an imagewise crosslinking reaction, and then the hydrophilic fine particles which are not chemically bonded are removed. And a hydrophilic region formed of hydrophilic fine particles chemically bonded to each other. The hydrophilic fine particles that have not been chemically bonded can be removed without using an eluate. Even when an eluate is used, a small amount of the eluate can remove hydrophilic fine particles that have not been chemically bonded. Therefore, in the method of making a lithographic printing plate according to the present invention, waste liquid treatment of the eluate is easy. The hydrophilic fine particles chemically bonded are in a good hydrophilic area (fountain solution receiving part)
Function as Further, the hydrophilic fine particles chemically bonded have excellent strength and high durability (printing durability). The exposed surface of the hydrophobic support can be used as a good hydrophobic region (ink receiving portion). Therefore, according to the present invention, a lithographic printing plate having high ink receptivity and high printing durability can be obtained.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION [Hydrophilic fine particles] The hydrophilic fine particles are preferably formed from an inorganic substance, and particularly preferably formed from silica. The hydrophilic fine particles preferably have a porous surface. The hydrophilic fine particles having a porous surface have high water retention and are preferably used for a lithographic printing plate. The average particle size of the hydrophilic fine particles is 0.0
The thickness is preferably from 1 to 10.0 μm, more preferably from 0.01 to 5.0 μm, and most preferably from 0.01 to 3.5 μm. The amount of the hydrophilic fine particles is preferably 0.1 to 10 g / m ^2, still preferably 0.1 to 5 g / m ^2, most in the range of 0.1 to 3 g / m ² preferable.

[Crosslinkable Surface] A crosslinkable surface is formed by modifying the surface of the hydrophilic fine particles. The crosslinkable group is
It can be directly bonded to a hydrophilic substance forming hydrophilic fine particles. However, it is preferable to introduce the crosslinkable group into a compound different from the hydrophilic substance forming the hydrophilic fine particles. The compound for introducing a crosslinkable group is preferably a polymer. The compound having a crosslinkable group (for example, an epoxy group) is adsorbed or bonded to the surface of the hydrophilic fine particles. The surface modification by adsorption is typically a surface coating method. The surface modification by bonding is typically a graft polymerization method. The surface modification of silica fine particles is described in Polymer (Katsushi Nagai, Vol. 48, April, 1999). For example, when surface modification of silica fine particles is performed using a reactive monomer such as glycidyl methacrylate, reactive composite particles in which the porosity of the silica fine particles is maintained can be obtained. It is also possible to graft-polymerize polyacrylamide chains onto silica gel particles using living radical polymerization (X. Huang, MJ Wirth; Anal. Chem.,
69, 4577 (1997)). Oligomeric chains can also be grafted with terminal polymer silane coupling agents (H. Ihara, et al .; Abstracts of International
Conference on Silica Science and Technology, Mulh
ouse, France (1998)).

Examples of the crosslinkable group include an active methine group, an active methylene group, an ethylenically unsaturated group, an acetylenically unsaturated group, an epoxy group, an amino group, a carboxyl group, a sulfo group, a hydroxyl group, a mercapto group, and an aldehyde. Groups, cyano groups, cyanato groups, thiocyanato groups, isocyanato groups and isothiocyanato groups. The specific type of the crosslinkable group is determined according to a crosslinking reaction (described later) in plate making of a lithographic printing plate.

[Cross-Linking Reaction] The cross-linking reaction is carried out imagewise on the lithographic printing plate precursor. That is, it is necessary to distinguish between a region where a crosslinking reaction occurs (finally a hydrophilic region) and a region where a crosslinking reaction does not occur (finally a hydrophobic region). For this purpose, energy for causing a cross-linking reaction may be applied to the lithographic printing plate precursor in accordance with the image. Light or heat is generally used as energy applied to an image. Therefore, when a photopolymerization initiator or a thermal polymerization initiator is added to a lithographic printing material layer, a crosslinking reaction can be caused in an exposed area or a heated area. A latent image may be formed by applying energy corresponding to the image, and a cross-linking reaction may be caused in the subsequent development process so as to correspond to the image. In the case of a photosensitive material using silver halide, an image is generally formed in two stages: formation of a latent image (image exposure) and development.

Means for causing a crosslinking reaction in the development processing of silver halide include (1) a method of crosslinking gelatin or an epoxy polymer using an oxidized product of a developer obtained by developing silver halide as a crosslinking agent (so-called tanning development method). ), (2) a method of polymerizing an ethylenically unsaturated group using an oxidized form of a silver halide-developed developer as a polymerization initiator (described in JP-A Nos. 45-11149 and 64-17047) and (3) A method of performing a coupling reaction between an oxidized form of a developing agent obtained by developing silver halide and an active methine group or an active methylene group (JP-A-55-98743).
Is described. It is particularly preferable to use the tanning development method (1). Hereinafter, the tanning development method will be mainly described.

[Lithographic Printing Material Layer] The lithographic printing material layer preferably contains a binder in addition to the aforementioned hydrophilic fine particles having a crosslinkable surface. It is preferable to use a polymer having a crosslinkable group as a binder. That is, in addition to the hydrophilic fine particles, the binder is preferably bonded by crosslinking. When gelatin or epoxy polymer is bonded to hydrophilic fine particles and crosslinked by tanning development, the lithographic printing material layer preferably contains gelatin as a binder. Gelatin may be used in combination with another hydrophilic polymer (eg, polyvinylpyrrolidone, starch, albumin, polyvinyl alcohol, gum arabic, hydroxyethyl cellulose).

The lithographic printing material layer may further contain a compound necessary for causing a crosslinking reaction. When a crosslinking reaction is caused by the tanning development method, a compound necessary for causing the crosslinking reaction is silver halide. Although silver halide can be added to a layer (photosensitive layer) different from the lithographic printing material layer, it is more preferable to add it to the lithographic printing material layer. The coating amount of silver halide is 0.0
It is preferably 1 to 5 g / m ² , more preferably 0.03 to 2 g / m ² , and most preferably 0.1 to 1.5 g / m ² . The thickness of the lithographic printing material layer is preferably from 0.07 to 13 μm, and more preferably from 0.2 to 5 μm.

As silver halide, silver chloride, silver bromide,
Any grain of silver iodide, or silver chlorobromide, silver chloroiodide, silver iodobromide, or silver chloroiodobromide can be used. The shape of the silver halide grains is preferably cubic or tetradecahedral, but is not limited to those having a regular crystal form, and may be those having an irregular crystal form or a complex form thereof. Potato-shaped,
Spherical, plate-like and plate-like crystal forms are included. In the case of tabular grains, the grain size is generally at least five times the grain thickness.
There is no particular limitation on the grain size of the silver halide.
Fine particles of 0.01 μm or less can also be used. Meanwhile, 1
Large particles of about 0 μm can also be used. With respect to grain size distribution, monodisperse grains are preferred over polydisperse emulsions.
Monodispersed emulsions are described in U.S. Pat. Nos. 3,574,628 and 3,655,394 and British Patent 1,413,748. The crystal structure of silver halide grains is
It may be uniform or the inside and the outside may have different halogen compositions. It may have a layered structure. Further, silver halides having different compositions may be joined by epitaxial joining. Further, it may be bonded to a compound other than silver halide. Examples of compounds other than silver halide include silver rhodan and lead oxide.

The silver halide grains may contain salts of other elements. Examples of other elements include copper, thallium, lead, bismuth, cadmium, zinc, chalcogens (eg, sulfur, selenium, tellurium), gold and VI.
Group II noble metals (eg, rhodium, iridium, iron, platinum, palladium) can be mentioned. Salts of these elements can be added during or after the formation of silver halide grains and included in the grains. Specific methods are described in U.S. Patent Nos. 1195432 and 1951933,
No. 2448060, No. 2628167, No. 2950
No. 972, No. 3488709, No. 3737313,
Nos. 3772031 and 4269927, and Research Disclosure (RD), No. 13,
No. 4, No. 13452 (June 1975). By adding an aqueous solution of an iridium compound to the emulsion during the preparation of the silver halide emulsion, iridium ions can be introduced into the silver halide grains. Examples of water-soluble iridium compounds include hexachloroiridium (II
I) acid salts and hexachloroiridium (IV) salts. Similarly, rhodium ions may be introduced into silver halide grains by adding an aqueous solution of a rhodium compound to the emulsion. Examples of the water-soluble rhodium compound include rhodium ammonium chloride, rhodium trichloride and rhodium chloride.

An iridium compound or a rhodium compound may be used by dissolving it in an aqueous solution of a halide for forming silver halide grains. Further, the aqueous solution of the iridium compound or the rhodium compound may be added before the particles are formed, or may be added during the formation of the particles. Further, it may be added during the period from grain formation to chemical sensitization treatment. It is particularly preferred to add while the particles are being formed. The iridium ion or the rhodium ion is preferably used in an amount of 10 ^{-9 to} 10 ^-3 mol, more preferably 10 ^{-7 to} 10 ^-5 mol, per 1 mol of silver halide. Two or more silver halide grains having different halogen compositions, crystal habits and grain sizes can be used in combination. Silver halide is preferably used as an emulsion. Silver halide emulsions are described in Research Disclosure (RD) Magazine, No. 17643 (December 1978), pp. 22-23, "I. Emulsion Production (Emulsion p.
reparation and types) "and No. 18716
(November 1979), page 648.

The silver halide emulsion is usually subjected to chemical sensitization after physical ripening. It is preferable to use silver halide grains having a relatively low fog value. Additives used in such a process are described in Research Disclosure Magazine, No. 1
No. 7643 and the same No. 18716. Regarding chemical sensitizers, 17643 (p. 23) and
No. 18716 (page 648, right column). Known additives other than those described above are also described in the above two Research Disclosures. For example, as for the sensitivity enhancer, 18716 (648
In the right column of the page), for the antifoggant and the stabilizer, N
o. No. 17643 (pages 24 to 25) and no. 18716
(From page 649, right column).

Silver halide emulsions can utilize the inherent sensitivity of silver halide without spectral sensitization. However, usually, the silver halide emulsion is used after spectral sensitization. Silver halide sensitizing dyes known in the photographic art can be used. Examples of sensitizing dyes include cyanine dyes, merocyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Spectral sensitizing dyes are used to adjust the spectral sensitivity of photosensitive materials to different light source wavelengths such as various lasers (eg, semiconductor laser, helium neon laser, argon ion laser, helium cadmium laser, YAG laser) and light emitting diodes. Can also be used. For example, applying a plurality of spectral sensitizing dyes having different spectral wavelengths to silver halide in the same or different photosensitive layers to enable writing on the same photosensitive material using light sources having different wavelengths. Can also. In addition to the sensitizing dye, a dye which does not itself have a spectral sensitizing effect or a compound which does not substantially absorb visible light and exhibits supersensitization (supersensitizer) can be added to the emulsion. Good. Spectral sensitizing dyes are described in Research Disclosure Magazine, No.
17643 (December 1978), pp. 23-24, supersensitizers are described in the same publication. 18716 (November 1979
Mon.), p. 649.

In order to improve photographic characteristics, additives such as an antifoggant, a silver development accelerator for promoting silver development, and a stabilizer may be added to the lithographic printing material layer. Examples thereof include mercapto compounds (described in JP-A-59-111636), azoles and azaindenes (described in Research Disclosure No. 17643, pages 24 to 25 (1978)), and carboxylic acids containing nitrogen. And phosphoric acids (described in JP-A-59-168442), cyclic amides (described in JP-A-61-151841), thioethers (described in JP-A-62-151842),
Polyethylene glycol derivatives (JP-A-62-1518)
No. 43), thiol (JP-A-62-15184).
No. 4), acetylene compounds (JP-A-62-87).
957) and sulfonamides (JP-A-62
-178232). As silver development accelerators or antifoggants, aromatic ring (carbon ring or heterocyclic) mercapto compounds (JP-A-6-31)
3967) is particularly preferred. Aromatic heterocyclic mercapto compounds, particularly mercaptotriazole derivatives, are more preferred. The mercapto compound may be added to the lithographic printing plate precursor as a mercapto silver compound (silver salt). The amount of these compounds used is 10 mol / mol silver halide.
^-7 mol to 1 mol.

A developer may be added to the lithographic printing material layer. Known surfactants may be added to the lithographic printing material layer. Any of a nonionic activator, an anionic activator, a cationic activator and a fluorine activator can be used. The surfactant is described in JP-A-2-195356. Sorbitans, polyoxyethylenes and fluorinated surfactants are particularly preferred.

[Hydrophobic support] As the support, paper, synthetic paper, synthetic resin (eg, polyethylene, polypropylene,
Polystyrene) laminated paper, plastic (eg, polyethylene terephthalate, polycarbonate, polyimide, nylon, cellulose triacetate) film, metal (eg, aluminum, aluminum alloy, zinc, iron, copper) plate, these metals are laminated or evaporated Paper or plastic film can be used. Aluminum plate, plastic film,
Paper and synthetic paper are preferred. Further, a composite sheet in which an aluminum sheet is laminated on a polyethylene terephthalate film is also preferable. When a hydrophilic material such as an aluminum plate is used, it can be used as a hydrophobic support by providing a hydrophobic undercoat layer described below.
The “hydrophobicity” of the hydrophobic support is preferably such that the contact angle with water is 50 degrees or more. Further, the surface of the hydrophobic support (the undercoat layer in the case where the following hydrophobic undercoat layer is provided) is preferably made of a substance having a water swelling degree of 10% or less.

[Hydrophobic Undercoat Layer] The hydrophobic undercoat layer is formed using a hydrophobic polymer. Hydrophobic polymers include:
Polyacrylic acid ester, polymethacrylic acid ester (eg, polymethyl methacrylate, polybenzyl methacrylate), polyacrylamide, polymethacrylamide, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethacrylonitrile, polyethylene, Polystyrene, polyvinyl pyridine, polyvinyl imidazole, polyvinyl butyral,
Polyvinyl formal, polyvinyl pyrrolidone, chlorinated polyethylene, chlorinated polypropylene, polyester,
Polyamide, polyurethane, polycarbonate, cellulose ether (eg, ethyl cellulose) and cellulose ester (eg, cellulose triacetate, cellulose diacetate, cellulose acetate propionate) are included. To improve the affinity between the hydrophobic undercoat layer and the lithographic printing material layer, an acidic group may be introduced into the hydrophobic polymer. Examples of the acidic group include a carboxyl, an acid anhydride group, a phenolic hydroxyl group, a sulfo, a sulfonamide and a sulfonimide. Carboxyl is particularly preferred. An acidic group can be introduced into a polymer by copolymerizing a monomer having an acidic group such as acrylic acid, methacrylic acid, styrene sulfonic acid or maleic anhydride during the synthesis of the polymer. The proportion of the repeating unit having an acidic group in the copolymer is preferably 1 to 60 mol%, more preferably 1 to 50 mol%, and most preferably 1 to 20 mol%. A homopolymer having an acidic group (eg, polyhydroxystyrene) may be used. The molecular weight of the hydrophobic polymer is 10
It is preferable that the number be in the range of 00 to 500,000. Two or more kinds of hydrophobic polymers may be used in combination.

[Optionally Provided Layer] The optional layer provided on the lithographic printing plate precursor is preferably a hydrophilic layer,
More preferably, the layer is a layer containing gelatin as a binder. A tanning developer can be added to the optional hydrophilic layer. To provide a back layer containing a matting agent or an overcoat layer containing a matting agent on the lithographic printing plate precursor for the purpose of reducing the adhesiveness of the front and back surfaces of the lithographic printing plate precursor and preventing adhesion when the lithographic printing plate precursors are stacked. Can be. As the matting agent, inorganic or organic solid particles that can be dispersed in a water-soluble polymer are used. Examples of materials for the matting agent include oxides (eg, silicon dioxide), alkaline earth metal salts, natural polymers (eg, starch, cellulose) and synthetic polymers. The particle size of the matting agent is preferably in the range of 0.5 to 50 μm. The coating amount of the matting agent is 0.1 to 1 g / m ^2.
Is preferably within the range. A fogging inhibitor, a silver development accelerator for accelerating silver development, a stabilizer, or a surfactant may be added to the optional hydrophilic layer.

FIG. 1 is a schematic sectional view of a lithographic printing original plate used in the present invention. As shown in FIG. 1, a lithographic printing material layer (2) and an overcoat layer (3) are provided on a hydrophobic support (1). Lithographic printing material layer (2)
Are silver halide particles (21) and hydrophilic fine particles (22)
And gelatin (23). Hydrophilic fine particles (22)
Has an epoxy polymer (24) bonded to its surface.
The overcoat layer contains a hydrophilic polymer (31).

[Exposure Step] Image exposure in the tanning development method is performed with light having a wavelength corresponding to the spectral sensitivity of silver halide. The wavelength is generally visible light, near ultraviolet light, or near infrared light, but X-rays or electron beams may be used. Examples of light sources include tungsten lamps, halogen lamps, xenon lamps, xenon flash lamps, mercury lamps,
Lamps such as carbon arc lamps, various lasers (eg, semiconductor laser, helium neon laser, argon ion laser, helium cadmium laser, Y
AG laser), a light emitting diode, a cathode ray tube and the like. The exposure amount is generally 0.001 to 10
00 μJ / cm ² , preferably 0.01 to 100 μJ
/ Cm ² . When the support is transparent, exposure can be performed through the support from the back side of the support.

FIG. 2 is a schematic cross-sectional view of a lithographic printing original plate during image exposure. As shown in FIG. 2, when the lithographic printing original plate is irradiated with light (L), a latent image (21a) is formed on the silver halide grains in the exposed portions. In contrast, there is no change in the unexposed portions of the silver halide grains (21).

[Tanning development step] The tanning development is performed using a developer. The tanning developer is usually added to the developer. The developer is generally an alkaline solution. The pH of the developer is preferably 9 or more. Examples of the alkaline substance used for adjusting the pH include sodium hydroxide, potassium hydroxide, sodium phosphate, potassium phosphate, lithium phosphate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, and ammonia. As a solvent for the developer, water is preferable. If necessary, an organic solvent may be added to water. The temperature of the developer is preferably from 5 to 40 ° C, more preferably from 20 to 35 ° C. The development time is preferably from 10 seconds to 10 minutes, and more preferably from 20 seconds to 3 minutes. After the development processing, the lipophilicity of the image area may be enhanced by processing with a liquid containing a mercapto compound (JP-A-4-324866).
No.). Further, an acidic treatment or a fixing treatment may be performed.

As the tanning developer, compounds having a benzenediol ring or a benzenetriol ring (eg, pyrogallol, hydroquinone, t-butylhydroquinone, catechol, phenylcatechol, nordihydroguaiaretinic acid, 3,3,3) ', 3'-Tetramethyl-5,6,5', 6'-tetrahydroxyspirobisindane) is used. A polymer containing a repeating unit having a benzenezendiol ring or a benzenetriol ring in a side chain can also be used as a tanning developer. The amount of tanning developer used is 0.0
It is preferably from 1 to 1 mol / mol Ag, and
More preferably, it is 3 to 1 mol Ag. The amount of the tanning developer added to the tanning developer is preferably 10 ^{-5 to} 10 ^-1 mol / l.

In addition to the tanning developer, an auxiliary developer can be used. Examples of auxiliary developing agents include amidole, metol and aminophenol. Metol is particularly preferred. The auxiliary developing agent can be added to a tanning developer or a silver halide photosensitive material.
The amount of the auxiliary developer is 5 to 20 times the amount of the tanning developer.
It is preferably 0 mol%.

FIG. 3 is a schematic sectional view of a lithographic printing original plate in tanning development. As shown in FIG. 3, when the lithographic printing plate precursor after image exposure is immersed in a tanning developer (D), the silver halide particles in the exposed part are developed and the silver image (2) is developed.
1b) is formed. The oxidized form of the tanning developer (quinone) generated during development is exposed to gelatin (23
a) and the epoxy polymer (24a) are crosslinked.
In contrast, the unexposed portions of the gelatin (23) and the epoxy polymer (24) do not change.

[Removal Step] The lithographic printing plate precursor after the tanning development is immersed in an eluent (generally hot water) and rubbed on the surface to remove uncrosslinked hydrophilic fine particles in the unexposed portions and to crosslink. A relief image composed of hydrophilic fine particles can be formed. The temperature of the hot water is preferably 40 to 70 ° C. The surface of the photosensitive material may be rubbed with a sponge or a brush. The formed relief image can be used as a lithographic printing plate by drying. As post-processing,
Heat treatment, light irradiation treatment, or chemical treatment may be performed.

FIG. 4 is a schematic cross-sectional view of the lithographic printing plate precursor during elution. As shown in FIG. 4, when the lithographic printing original plate after the tanning development is treated with the eluent (S), the overcoat layer and the unexposed lithographic printing material layer are eluted. The lithographic printing material layer (2a) in the exposed area comprises a cross-linked gelatin (23a) and a cross-linked epoxy polymer (24
Due to the presence of a), a relief image is formed by remaining on the hydrophobic support (1). In this way, a lithographic printing plate can be made.

[0033]

[Example 1] [Production of polyethylene terephthalate support] Thickness 17
Polystyrene sulfonic acid (coating amount: 2.2 mg / m 2)
²⁾ and poly (3,4-ethylenedioxythiophene) (coating amount: 0.9 mg / m ²⁾ made of antistatic backside undercoat layer (total coating amount: 3.1 mg / m ²⁾ and the provided.
A first back layer made of gelatin (coating amount: 0.08 g / m ² ) was provided thereon. On the first back layer, gelatin (coating amount: 2.8 g / m ² ), transparent spherical polymer beads having an average particle size of 3 μm (coating amount: 0.065 g / m ² )
m ² ), barium sulfate dispersion having an average particle diameter of 0.3 to 0.4 μm (coating amount: 1.5 g / m ² ), colloidal silica (coating amount: 3.0 g / m ² ), triacrylformal ( A second back layer composed of a coating amount: 0.05 g / m ² ) and ammonium perfluorooctanoate (coating amount: 0.021 g / m ² ) was provided. Corona discharge treatment was performed on the front side of the polyethylene terephthalate film to produce a polyethylene terephthalate support.

"Preparation of Epoxy-Modified Silica Fine Particles" Colloidal silica having a particle size of 70 to 100 nm (ST-ZL,
Nissan Chemical Co., Ltd.) was surface-modified with 2-methacryloyloxypropyltrimethoxysilane. Then, glycidyl methacrylate and n-butyl acrylate,
Polymerization was performed on the modified surface of colloidal silica by a seed polymerization method using potassium persulfate as a polymerization initiator. In this way, a dispersion of epoxy-modified silica fine particles having colloidal silica as a core and having a shell made of a polymer having an epoxy group in a side chain was prepared. Solid content is 1
7.9% by weight, the average particle size was 185 nm, and the coefficient of variation of the particle size was 24%.

"Preparation of silver halide emulsion" A 5% by weight aqueous solution of gelatin containing sodium chloride at a pH of 2 was kept at 40 ° C., and an aqueous solution of silver nitrate and pentachloroacolodium (III) were added.
An aqueous solution of sodium chloride and potassium bromide containing ammonium acidate (6.0 × 10 ⁻⁷ mol / mol Ag) was added by a double jet method at a silver potential of 90 mV for 8 minutes, and the core of the silver halide grains was removed. Formed. Next, an aqueous silver nitrate solution, potassium hexachloroiridate (III) (1.5 × 10 ⁻⁵ mol / mol Ag) and potassium hexacyanoferrate (II) (2.0 × 10 ⁻⁵ mol / mol Ag) were added. An aqueous solution of sodium chloride and potassium bromide was added by a double jet method at a silver potential of 90 mV for 10 minutes, and an average grain size of 0.25 μm and silver chloride of 9% were added.
Silver chlorobromide cubic grains containing 0 mol% were prepared. After washing with water and desalting, 22 g of gelatin, 2 ml of 1N aqueous sodium hydroxide solution and 4 m of 10% by weight aqueous sodium chloride solution
The pH was adjusted to 5.8 and pAg 7.4. Next, 5,6-cyclopentane-4-hydroxy-1,
3,3a, 7-Tetrazaindene (1.25 × 10 ⁻³ mol / mol Ag) was added, and chemical sensitization was performed with sodium thiosulfate and chloroauric acid at 60 ° C. for 60 minutes. After completion of the chemical sensitization, the temperature was lowered to 45 ° C., and the mixture was combined with 5,6-cyclopentane-4-hydroxy-1,3,3a, 7-tetrazaindene (1.25 × 10 ⁻³ mol / mol Ag). 5- (2
Sodium mercaptobenzothiazole) sulfonate (1.7 × 10 ⁻⁴ mol / mol Ag).

"Formation of lithographic printing material layer" To 100 g of a dispersion of epoxy-modified silica fine particles was added 25 g of a silver halide emulsion heated at 45 ° C, and the mixture was stirred for 20 minutes.
H was adjusted to 6.5 to prepare a coating solution. A coating liquid was applied to the corona discharge treated surface of the polyethylene terephthalate support to form a lithographic printing material layer. The coated silver amount (equivalent to silver nitrate) is 0.7 g / m ² , and the gelatin coated amount is 0.9 g / m ² .
^{2. The} amount of the epoxy polymer applied was 0.9 g / m ² .

[Formation of Overcoat Layer] A coating aid was added to a 4% by weight aqueous solution of polyvinyl alcohol (PVA-117, manufactured by Kuraray Co., Ltd.), and 0.8 g / m ² of 0.8 g / m ² was formed on the lithographic printing material layer. Coating was carried out in the application amount to form an overcoat layer. Thus, a lithographic printing original plate was produced.

"Preparation of tanning developer" A solution A and a solution B having the following compositions were prepared, and they were mixed immediately before use.

液 Liquid A ───────── ─────────────────────────── Pyrogallol 3.0 g Metol 1.0 g Citric acid 1.0 g Water 500 ml ──────── ────────────────────────────

液 Liquid B ─────────カ リ ウ ム Potassium carbonate 200g Potassium bromide 1.0g Water 500ml ──────────── ────────────────────────

(Image formation) 400 nm using a xenon sensitometer
The printing original for print quality evaluation was brought into close contact with the lithographic printing original plate using the interference filter described above, and image exposure was performed with an emission time of 10 ^-5 seconds. The lithographic printing plate precursor subjected to image exposure was immersed in the above tanning developer at 24 ° C. for 30 seconds. Then
After washing with warm water at 40 ° C., the lithographic printing material layer in the unexposed area was removed together with the overcoat layer, and a clear relief image was obtained in the exposed area. In this way, a lithographic printing plate was prepared in which the hydrophilic relief image in the exposed area was ink repellent and the hydrophobic support exposed in the unexposed area due to elution was ink-receiving. Lithographic printing press (SORM, manufactured by Heidelberg)
Was used to print a lithographic printing plate. The fountain solution was prepared by diluting raw water for fountain solution (EU-3, manufactured by Fuji Photo Film Co., Ltd.) 100 times with water and adding 10% by weight of isopropyl alcohol. The ink used was black ink (Gloss Ink, manufactured by Dainippon Ink Co., Ltd.). After the start of printing, a clear printed matter was obtained from the eighth sheet. Good printed matter was stably obtained up to 10,000 sheets.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a lithographic printing original plate used in the present invention.

FIG. 2 is a schematic cross-sectional view of a lithographic printing original plate during image exposure.

FIG. 3 is a schematic cross-sectional view of a lithographic printing original plate in tanning development.

FIG. 4 is a schematic cross-sectional view of a lithographic printing plate precursor during elution.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hydrophobic support 2 Lithographic printing material layer 2a Lithographic printing material layer of an exposed part 21 Silver halide particle 21a Latent image of silver halide particle 21b Silver image 22 Hydrophilic fine particle 23 Gelatin 24 Bonded to the surface of hydrophilic fine particle Epoxy polymer 23a Crosslinked gelatin 24a Crosslinked epoxy polymer 3 Overcoat layer 31 Hydrophilic polymer D Tanning developer L Light S Eluent

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03F 7/09 501 G03F 7/09 501 7/38 512 7/38 512 // G03F 7/032 7/032 F term ( Reference) 2H025 AA00 AB03 AC01 AD01 AD03 CA15 CB03 CC08 CC20 DA18 FA03 FA12 FA17 2H084 AA13 AA25 AA30 AA32 AA40 BB02 BB04 BB13 CC05 2H096 AA07 BA17 BA20 CA05 FA05 GA08 JA03 2H114 AA04 DA24 DA27 DAA DA DA DA DA DA DA DA DA75 EA03 FA16 GA31 GA36

Claims (6)

[Claims] 1. A lithographic printing plate precursor having a lithographic printing material layer composed of hydrophilic fine particles having a crosslinkable surface on a hydrophobic support, is subjected to an imagewise crosslinking reaction to chemically bond the hydrophilic fine particles to each other. Binding; removing the hydrophilic fine particles that have not been chemically bonded to form a hydrophobic region consisting of the exposed support surface and a hydrophilic region consisting of the chemically bonded hydrophilic fine particles. And a method of making a lithographic printing plate in this order. 2. A lithographic printing material layer or a photosensitive layer provided adjacent to the lithographic printing material layer contains silver halide, and after performing a step of imagewise exposing the lithographic printing original plate, developing the silver halide using a developing agent. 2. The plate-making method according to claim 1, wherein the cross-linkable surface of the hydrophilic fine particles is subjected to an image-wise cross-linking reaction with an oxidized form of a developing agent. 3. The plate-making method according to claim 1, wherein a crosslinkable surface is formed on the hydrophilic fine particles by attaching or binding the epoxy compound to the surface of the hydrophilic fine particles. 4. The plate making method according to claim 1, wherein the hydrophilic fine particles are made of silica. 5. The plate making method according to claim 1, wherein the lithographic printing material layer further contains gelatin as a binder. 6. A relief image composed of chemically bonded hydrophilic fine particles is formed on a hydrophobic support, and the chemically bonded hydrophilic fine particles function as hydrophilic regions,
A lithographic printing plate wherein the exposed surface of the support functions as a hydrophobic region.