JP2002178657A - Original plate for heat-sensitive lithographic printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original plate for heat-sensitive lithographic printing which can be mounted on a printing machine as it is without processing after the original plate is scanned and exposed to light based on a digital signal and used for printing and further, is highly suitable for printing in terms of unsusceptibility to smear, resistance to plate wear, ink receptivity and the like. SOLUTION: This original plate for heat-sensitive lithographic printing has (1) an ink receptive layer and (2) a hydrophilic layer containing a colloidal particle-like oxide or hydroxide of at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germaniums, tin, zirconium, iron, vanadium, antimony and a transition metal, laminated on a grained aluminum substrate with an anodized surface in that order. In addition, at least either of the ink receptive layer or the hydrophilic layer contains a photothermal conversion, agent and the average roughness Ra, in the centerline, of the surface of the hydrophilic layer is 0.45 μm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive lithographic printing plate not requiring development. More specifically, image recording by infrared laser beam scanning exposure based on digital signals is possible, and the recorded image can be mounted on a printing machine and printed without going through the conventional development process The present invention relates to a lithographic printing plate having excellent printability.

[0002]

2. Description of the Related Art A computer-to-printer for producing a printing plate by laser beam scanning exposure based on a digital signal.
A number of studies have been made on plate systems. Among them, with the aim of further streamlining the process and solving the problem of waste liquid treatment, development-free lithographic printing plates that can be mounted on a printing machine and printed without exposure after development have been studied. Various methods have been proposed as described in the Journal of the Society, Vol. 36, pp. 148-163 (1999).

One promising approach is to use a semiconductor laser, YA
This is a method using ablation in which exposure is performed with a solid-state high-output infrared laser such as a G laser, the exposed portion is heated by a photothermal conversion agent that converts light into heat, and decomposition and evaporation occur. That is, a hydrophilic layer is provided on a lipophilic ink-receiving surface or a substrate having an ink-receiving layer, and the hydrophilic layer is ablated and removed.

[0004] WO 94/18005 discloses a printing plate in which a crosslinked hydrophilic layer is provided on a lipophilic laser light absorbing layer, and the hydrophilic layer is ablated. The hydrophilic layer is formed by cross-linking polyvinyl alcohol with a hydrolyzate of tetraethoxysilicon and containing titanium dioxide particles to improve the film strength of the hydrophilic layer. This technology improves press life. However, the stain resistance was insufficient and further improvement was required.

[0005] WO98 / 40212 and WO99
/ 19143 has an ink receiving layer and a hydrophilic layer mainly composed of a colloid such as silica cross-linked with a cross-linking agent such as aminopropyltriethoxysilane on a substrate. A lithographic printing plate that can be mounted is disclosed. The hydrophilic layer has reduced hydrocarbon groups as much as possible to enhance the resistance to printing stains, and improves the printing durability by crosslinking the colloid with a crosslinking agent. However, this technique has insufficient printing durability of several thousand sheets.

JP-A-11-301130 is characterized in that a recording layer whose hydrophilicity is reduced by heat and a hydrophilic layer having a maximum absorption in an infrared region are formed in this order on a support. Lithographic printing materials are described. It is described therein that by setting the center line roughness Ra of the surface to preferably 0.3 μm or more, more preferably 0.5 or more, it is possible to improve the water retention property related to the difficulty in soiling.
However, since the surface roughness in this publication is obtained by adding a filler such as silica to the recording layer or the hydrophilic layer, the mechanical strength may be reduced depending on the material and filler used for the matrix of the recording layer or the hydrophilic layer. There are problems such as lowering the ink quality and insufficient ink receptivity, which limits the selection of materials.

[0007]

As described above, the unprocessed printing plate utilizing ablation of the prior art has a problem that printing performance such as stain resistance, printing durability and ink receptivity is impaired. . It is an object of the present invention to solve this problem. That is, it is possible to print by directly mounting on a printing machine without performing post-exposure processing,
An object of the present invention is to provide a heat-sensitive lithographic printing plate having good printing suitability such as printing durability and ink acceptability.

[0008]

Means for Solving the Problems The present inventor has found that the above object can be achieved by the following constitution. That is, the present invention is as follows.

1. (1) an ink-receiving layer on a grained and anodized aluminum substrate
And (2) a colloidal particulate oxide or hydroxide of at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals. A heat-sensitive lithographic printing plate having a hydrophilic layer in this order, wherein at least one of the ink receiving layer and the hydrophilic layer contains a light-to-heat conversion agent, and the center line average roughness Ra of the hydrophilic layer surface is zero. .45μ
m or more, which is a heat-sensitive lithographic printing plate.

[0010] 2. On the aluminum substrate according to the above item 1,
A heat-sensitive lithographic printing plate having, in this order, (1) an ink receiving layer, (2) a hydrophilic layer as described in 1 above, and (3) a hydrophilic overcoat layer that can be removed on a printing press, wherein the ink receiving layer is provided. Heat-sensitive lithographic printing wherein at least one of the hydrophilic layer and the hydrophilic overcoat layer contains a light-to-heat conversion agent, and the center line average roughness Ra of the hydrophilic layer surface is 0.45 μm or more. Original plate.

As described above, in the present invention, a grained aluminum plate is used for the support to increase the surface roughness of the hydrophilic layer which is the outermost surface during printing. As a result, good water retention can be obtained without adding substances that may adversely affect printing durability and ink receptivity to the ink receiving layer and the hydrophilic layer. Thus, it became easy to obtain a heat-sensitive lithographic printing plate having good printing performance.

[0012]

Embodiments of the present invention will be described below in detail. In the present invention, a grained (hereinafter, also referred to as “roughened”) aluminum substrate is used as a support. As the raw aluminum plate for this purpose, an aluminum plate of a conventionally known and used material can be appropriately used. That is, the raw aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of a different element. The foreign elements contained in aluminum alloys include silicon, iron, manganese, copper, magnesium,
There are chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is 10% by weight or less.
Further, an aluminum plate from an aluminum ingot using the DC casting method or an aluminum plate from an ingot using the continuous casting method may be used.

The thickness of the aluminum substrate used in the present invention is 0.05 to 0.6 mm, preferably 0.1 to 0.6 mm.
It is 0.4 mm, particularly preferably 0.15 to 0.3 mm.

The surface roughening treatment of the aluminum plate surface can be performed by various methods. For example, it can be performed by a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, a method of chemically selectively dissolving the surface, or a combination of two or more of these methods. . Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. As a chemical method, Japanese Patent Application Laid-Open No.
The method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in Japanese Patent No. 31187 is suitable. As an electrochemical surface roughening method, there is 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. Also, an electrolytic surface roughening method using a mixed acid as disclosed in JP-A-54-63902 can be used.

The roughened aluminum plate is subjected to an alkali etching treatment with an aqueous solution of potassium hydroxide or sodium hydroxide, if necessary, further neutralized, and then anodized.

As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes for forming a porous oxide film can be used. Generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, sulfamic acid, Benzenesulfonic acid,
Alternatively, their mixed acids are used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte. Anodizing treatment conditions vary depending on the electrolyte to be used, and thus cannot be specified unconditionally.
80% by weight solution, liquid temperature 5 to 70 ° C, current density 5 to 60
A / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 50 minutes are appropriate. Among these anodizing treatments, in particular, a method of anodizing with high current density in sulfuric acid described in British Patent No. 1,412,768 and US Pat. No. 3,511,661 are described. A method of performing anodic oxidation using phosphoric acid as an electrolytic bath is preferable. The oxide film amount of the aluminum support of the present invention is preferably 2.0 g / m ² or more, and more preferably 2.0 to 6.0 g.
/ M ² , particularly preferably 2.0 to 4.0 g / m ² .

As the substrate used in the present invention, a substrate having the above-mentioned surface treatment and having an anodic oxide film may be used as it is. However, if necessary, it is necessary to further improve the adhesiveness with the upper layer and the heat insulating property. Japanese Patent Application No. 2000-65219 and Japanese Patent Application No. 2000-14387 described in Japanese Patent Application No. 2000-14387, enlarging the micropores of the anodized film, sealing the micropores, and immersing the surface in an aqueous solution containing a hydrophilic compound. And the like can be appropriately selected and performed.
Suitable hydrophilic compounds for the hydrophilization treatment include:
Examples include polyvinylphosphonic acid, compounds having a sulfonic acid group, saccharide compounds, citric acid, alkali metal silicates, potassium zirconium fluoride, and phosphate / inorganic fluorine compounds.

The surface roughness of the aluminum substrate obtained as described above has a center line average roughness Ra of preferably 0.48 μm or more, more preferably 0.52 μm or more. R
The upper limit of “a” is difficult to determine unequivocally because it is related to the coating thickness of the ink receiving layer and the hydrophilic layer applied thereon, but generally it is preferably up to about 0.7 μm. Within this range, the surface roughness on the surface of the hydrophilic layer becomes sufficiently large, and good water retention is secured.

The ink receiving layer used in the present invention contains an organic polymer. The organic polymer is soluble in a solvent and can form a lipophilic film. Moreover,
It is desirable that the solvent is insoluble in the coating solvent of the upper hydrophilic layer. However, in some cases, a material which swells in the upper layer coating solvent has excellent adhesiveness to the hydrophilic layer, and may be desirable.
In addition, when an organic polymer that is soluble in the coating solvent for the hydrophilic layer is used, it is desirable to cure the ink receiving layer by devising, for example, adding a crosslinking agent.

Examples of useful organic polymers include polyester, polyurethane, polyurea, polyimide, polysiloxane, polycarbonate, phenoxy resin, epoxy resin, novolak resin, resol resin, condensation resin of phenol compound and acetone, polyvinyl acetate, and acrylic resin. And its copolymer, polyvinylphenol,
Polyvinylhalogenated phenol, methacrylic resin and its copolymer, acrylamide copolymer, methacrylamide copolymer, polyvinylformal, polyamide,
Examples thereof include polyvinyl butyral, polystyrene, cellulose ester resin, polyvinyl chloride and polyvinylidene chloride. Among these, as a more preferable compound, a resin having a hydroxyl group, a carboxyl group, a sulfonamide group or a trialkoxysilyl group in a side chain is excellent in adhesion to a substrate or an upper hydrophilic layer, and in some cases, a crosslinking agent. It is desirable because it cures easily. In addition, an acrylonitrile copolymer, polyurethane, a copolymer having a sulfonamide group in a side chain or a copolymer having a hydroxyl group in a side chain, which is photocured with a diazo resin, is preferable.

Examples of the epoxy resin suitable for the ink receiving layer of the present invention include bisphenol A / epichlorohydrin polyadduct, bisphenol F / epichlorohydrin polyadduct, and halogenated bisphenol A / epichlorohydrin. Examples include polyadducts, biphenyl-type bisphenol / epichlorohydrin polyadducts, and novolak resin / epichlorohydrin polyadducts. Specifically, Epicoat 1007 manufactured by Yuka Shell Epoxy Co., Ltd.
(Softening point 128 ° C, Mn about 2900, epoxy equivalent 20
00), Epicoat 1009 (softening point 144 ° C, Mn about 3
750, epoxy equivalent 3000), Epicoat 1010
(Softening point 169 ° C, Mn about 5500, epoxy equivalent 400
0), Epicoat 1100L (softening point 149 ° C, epoxy equivalent 4000), Epicoat YX31575 (softening point 130 ° C, epoxy equivalent 1200), and the like.

Novolak resins and resol resins include phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol Modified xylene, t-butylphenol, octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl,
p-Cl), bromophenol (m-Br, p-B
r), addition condensation products of salicylic acid, phloroglucinol and the like with aldehydes such as formaldehyde and paraformaldehyde.

As other suitable high molecular compounds, there can be mentioned copolymers having an average molecular weight of usually from 100,000 to 200,000, wherein the monomers shown in the following (1) to (12) are constituent units. (1) acrylamides having an aromatic hydroxy group,
Methacrylamides, acrylates, methacrylates and hydroxystyrenes such as N
-(4-hydroxyphenyl) acrylamide or N
-(4-hydroxyphenyl) methacrylamide, o
-, M- and p-hydroxystyrene, o-, m- and p-hydroxyphenyl acrylate or methacrylate, (2) acrylates and methacrylates having an aliphatic hydroxy group, for example,
2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate,

(3) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, acrylic acid-2 Acrylates such as -chloroethyl, 4-hydroxybutyl acrylate, glycidyl acrylate, N, N-dimethylaminoethyl acrylate, (4) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, Hexyl methacrylate,
Cyclohexyl methacrylate, octyl methacrylate,
Methacrylates such as phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate, and N, N-dimethylaminoethyl methacrylate;

(5) Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N
-Hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N
Acrylamides such as -phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N-ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide Or methacrylamide,

(6) Ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and phenyl vinyl ether; (7) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate; (8) styrenes such as styrene, methyl styrene and chloromethyl styrene; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone;
(10) olefins such as ethylene, propylene, isobutylene, butadiene and isoprene; (11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc.

(12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) Naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Acrylamide or methacrylamides containing a sulfonamide group such as phenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide;
Further, o-aminosulfonylphenyl acrylate, m
-Aminosulfonylphenyl acrylate, p-aminosulfonylphenyl acrylate, 1- (3-aminosulfonylphenylnaphthyl) acrylate, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3 -Sulfonamide group-containing acrylates or methacrylates such as -aminosulfonylphenylnaphthyl) methacrylate.

These organic polymers can be dissolved in an appropriate solvent, applied to a substrate and dried to form an ink receiving layer on the substrate. Although only an organic polymer can be used by dissolving it in a solvent, a crosslinking agent, an adhesion aid, a coloring agent, a coating surface condition improving agent, and a plasticizer can be added as necessary. In addition, a heat coloring or decoloring additive for forming a printout image after exposure may be added.

As a crosslinking agent for crosslinking an organic polymer,
For example, a diazo resin, an aromatic azide compound, an epoxy resin, an isocyanate compound, a blocked isocyanate compound, an initial hydrolysis condensate of tetraalkoxy silicon, glyoxal, an aldehyde compound and a methylol compound can be exemplified.

As the adhesion aid, the above diazo resin is excellent in adhesion to the substrate and the hydrophilic layer. In addition, a silane coupling agent, an isocyanate compound, and a titanium coupling agent are also useful.

As the coloring agent, ordinary dyes and pigments can be used. In particular, rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, quinizarin, 2- (α-naphthyl) -5- Phenyloxazole and the like. Specific examples of other dyes include Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green B
G, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, Crystal Violet (CI
42555), methyl violet (CI4253)
5), ethyl violet, methylene blue (CI52
015), patent pure blue (manufactured by Sumitomo Sangoku Chemical), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4-p-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc. Triphenylmethane series represented by
Diphenylmethane, oxazine, xanthene, iminonaphthoquinone, azomethine or anthraquinone dyes or JP-A-62-293247,
Dyes described in JP-A-9-179290 can be exemplified. When the above dye is added to the ink receiving layer, it is usually used in an amount of about 0.0
The proportion is 2 to 10% by weight, more preferably about 0.1 to 5% by weight.

Further, fluorine-based surfactants and silicon-based surfactants which are well-known compounds as coating surface condition improvers can also be used. Specifically, a surfactant having a perfluoroalkyl group or a dimethylsiloxane group is useful for preparing the coated surface.

Further, a plasticizer may be added to the ink receiving layer of the present invention, if necessary, in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic acid or methacrylic acid And a polymer.

The color-forming or decoloring-type additives that can be added to the ink receiving layer of the present invention include, for example, thermal acid generators such as diazo compounds and diphenyliodonium salts and leuco dyes (leucomalachite green, leuco crystal). Violet, a lactone of crystal violet, etc.) and a PH discoloration dye (for example, a dye such as ethyl violet or Victoria Pure Blue BOH) are used in combination. In addition, a combination of an acid coloring dye and an acidic binder as described in EP 897134 is also effective. In this case, the bond in the associated state forming the dye is broken by heating, and a lactone is formed to change from colored to colorless. The proportion of these additives is preferably 10% by weight or less, more preferably 5% by weight or less, based on the solid content of the ink receiving layer.

As the solvent for coating the ink receiving layer, alcohols (methanol, ethanol, propyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol,
Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), ethers (tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, tetrahydropyran, etc.), ketones (acetone, methyl ethyl ketone, acetylacetone, etc.), esters ( Methyl acetate, ethyl acetate, ethylene glycol monomethyl ether monoacetate, gamma-butyrolactone, methyl lactate, ethyl lactate, and the like, amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone, and the like) can be used. These solvents are used alone or as a mixture. The concentration of the ink receiving layer component (total solid content including additives) in the coating liquid is preferably 1 to 50% by weight. In addition, a film can be formed not only from the above-mentioned application from an organic solvent but also from an aqueous emulsion. In this case, the concentration is preferably 5% by weight to 50% by weight.

The dry coating amount of the ink-receiving layer of the present invention varies in relation to the surface roughness of the aluminum substrate, and thus cannot be unconditionally determined, but is preferably 0.25 to 0.7 g / m 2.
² , more preferably 0.35 to 0.5 g / m ² . Within this range, the water retention of the hydrophilic layer can be ensured without impairing the printing durability and chemical resistance of the image area.

The hydrophilic layer of the present invention comprises a colloidal particulate oxide of at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals. Or contains a hydroxide.

The colloidal particulate oxides or hydroxides of these elements can be dispersed in the colloidal dispersion liquid by various known methods such as hydrolysis of halides or alkoxy compounds of the above elements or condensation of hydroxides. Ie, made as colloidal particles. When it is added to a hydrophilic layer coating solution for forming a hydrophilic layer, it can be added in the form of a colloidal dispersion.

Of the oxides or hydroxides of these elements, particularly preferred are oxides or hydroxides of at least one element selected from aluminum, silicon, titanium and zirconium.

The colloidal particles of oxides or hydroxides of these elements have a colloidal particle size of 5% in the case of silica.
Spherical ones of 〜100 nm are preferred. 10-50n
Colloidal particles in the form of pearl necklaces in which m spherical particles are connected in a length of 50 to 400 nm can also be used. Feathers such as 100 nm × 10 nm, such as colloidal particles of aluminum oxide or hydroxide, are also effective. These colloidal dispersions can be purchased from commercial products such as Nissan Chemical Industries, Ltd.

As a dispersion medium of these colloid particles,
In addition to water, organic solvents such as methanol, ethanol, ethylene glycol monomethyl ether, and methyl ethyl ketone are also useful.

In the hydrophilic layer of the present invention, a hydrophilic resin can be used together with the above colloid particles. By using a hydrophilic resin, the film properties of the hydrophilic layer can be enhanced, and the printing durability can be improved. Examples of the hydrophilic resin include hydroxyl,
Those having a hydrophilic group such as carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl and carboxymethyl are preferred. Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and their sodium salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymer, styrene-maleic acid copolymer, polyacrylic acid and , Polymethacrylic acid 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 And copolymers of hydroxybutyl acrylate Chromatography, polyethylene glycol, polypropylene oxide, polyvinyl alcohol, and hydrolysis degree of at least 60 wt%, preferably at least 8
0% by weight of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide,
Examples thereof include homopolymers and copolymers of N-methylolacrylamide.

The proportion of these hydrophilic resins added is preferably 40% by weight or less, more preferably 20% by weight or less, of the solid content of the hydrophilic layer.

Further, for the hydrophilic layer of the present invention, a resin having an aromatic hydroxyl group can be used. When a resin having an aromatic hydroxyl group is used, it is possible to improve the film-forming properties of the hydrophilic layer and, at the same time, improve the inking property of printing. As the resin having an aromatic hydroxyl group, methanol is added at 25 ° C for 5 hours.
It is preferable that the resin dissolves in an amount of at least% by weight, and examples thereof include alkali-soluble resins such as novolak resins, resole resins, polyvinylphenol resins, and ketone pyrogallol resins.

Preferred novolak resins include at least one hydroxyl-containing aromatic compound selected from phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, and resorcinol. And a novolak resin which is addition-condensed with at least one selected from aldehydes such as formaldehyde, acetaldehyde and propionaldehyde in the presence of an acidic catalyst. Instead of formaldehyde and acetaldehyde, paraformaldehyde and paraaldehyde, respectively, may be used. Among them, the mixing ratio of m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol: resorcinol is 40 to 100: 0 to 50: 0 to 20: 0 to 2 in a molar ratio.
A mixture of 0: 0 to 20 or a mixing ratio of phenol: m-cresol: p-cresol is 1 to 10 in molar ratio.
A novolak resin which is an addition condensation product of a mixture of 0: 0 to 70: 0 to 60 and an aldehyde is preferred. Of the aldehydes, formaldehyde is particularly preferred. The weight average molecular weight of the novolak resin is preferably 1,000 to 1
5,000, more preferably 1,500 to 10,000
0 is used.

Preferred resole resins include phenol, m-cresol, o-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, resorcinol, pyrogallol, bis- (4-hydroxyphenyl) methane, bisphenol -A, o-ethylphenol, m-ethylphenol, p-ethylphenol,
Hydroxy group-containing aromatic hydrocarbons such as propylphenol, n-butylphenol, t-butylphenol, 1-naphthol, and 2-naphthol, and at least one other polynuclear aromatic hydrocarbon having two or more hydroxyl groups, Examples thereof include those obtained by addition condensation with an aldehyde such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and furfural, and at least one aldehyde selected from ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone under a catalyst. Instead of formaldehyde and acetaldehyde, paraformaldehyde and paraaldehyde, respectively, may be used. The weight average molecular weight of the resole resin is preferably 500 to 10,000.
00, particularly preferably 1,000 to 5,000.

Preferred polyvinyl phenol resins include o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene and 2- (m-hydroxyphenyl)
Examples thereof include homopolymers of hydroxystyrenes such as propylene and 2- (p-hydroxyphenyl) propylene, or copolymers of two or more thereof. Hydroxystyrenes may have a halogen such as chlorine, bromine, iodine, fluorine or a substituent such as an alkyl group having 1 to 4 carbon atoms in the aromatic ring. And a polyvinyl phenol which may have a halogen or an alkyl group having 1 to 4 carbon atoms.

In addition, o-hydroxystyrene, m
-Hydroxystyrene, p-hydroxystyrene, 2-
Hydroxystyrenes such as (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene, 2- (p-hydroxyphenyl) propylene,
Those obtained by copolymerizing methacrylic acid, acrylic acid, alkyl methacrylate or alkyl acrylate are also useful. The polyvinylphenol resin is usually obtained by polymerizing hydroxystyrene which may have a substituent, alone or in combination of two or more in the presence of a radical polymerization initiator or a cationic polymerization initiator. Such a polyvinyl phenol resin may be partially hydrogenated. Further, a resin in which some hydroxyl groups of the polyvinyl phenol resin are protected by a t-butoxycarbonyl group, a pyranyl group, a furanyl group, or the like may be used. The weight average molecular weight of the polyvinyl phenol resin is preferably 1,0.
00 to 100,000, particularly preferably 1,500 to 5
It is 0000. As ketone pyrogallol resin,
Acetone pyrogallol resins are particularly useful.

The proportion of the resin having an aromatic hydroxyl group to be added is preferably not more than 20% by weight, more preferably not more than 12% by weight of the solid content of the hydrophilic layer.

In the hydrophilic layer of the present invention, in addition to a resin having an aromatic hydroxyl group and a colloidal oxide or hydroxide of the above-described element, a crosslinking agent for accelerating the crosslinking of the colloidal oxide or hydroxide is used. It may be added. As such a crosslinking agent, an initial hydrolysis condensate of tetraalkoxysilane, trialkoxysilylpropyl-N, N, N-trialkylammonium halide, or aminopropyltrialkoxysilane is preferable. The addition ratio is
It is preferably 5% by weight or less of the solid content of the hydrophilic layer.

Further, to the hydrophilic layer of the present invention, a crosslinking agent for the above-mentioned hydrophilic resin or a resin having an aromatic hydroxyl group may be added for the purpose of increasing the printing durability during printing. Examples of such a crosslinking agent include formaldehyde, glyoxal, polyisocyanate, an initial hydrolysis / condensate of tetraalkoxysilane, dimethylol urea and hexamethylol melamine.

The hydrophilic layer according to the present invention may further include a well-known fluorine-based surfactant for improving the surface condition of the coating.
A silicon-based surfactant, a polyoxyethylene-based surfactant, or the like may be added.

The dry coating amount of the hydrophilic layer of the present invention is preferably from 0.2 to 0.8 g / m ² , more preferably from 0.3 to 0.8 g / m ² .
0.5 g / m ² . Within this range, good water retention of the hydrophilic layer can be obtained without lowering the on-press developability or lowering the sensitivity.

The heat-sensitive lithographic printing plate precursor of the present invention is capable of preventing the hydrophilic layer from being contaminated or damaged by a lipophilic substance during storage and handling, preventing fingerprints from adhering when handled with bare hands, and reducing generation of scum due to ablation. Therefore, a hydrophilic overcoat layer can be provided on the hydrophilic layer.

The hydrophilic overcoat layer used in the present invention can be removed on a printing press, and is made of a resin selected from a water-soluble resin or a water-swellable resin obtained by partially cross-linking a water-soluble resin. contains.

Such a water-soluble resin is selected from a water-soluble natural polymer and a synthetic polymer, and is used in combination with a crosslinking agent, and the coated and dried film has a film-forming ability.
Specific examples of the water-soluble resin preferably used in the present invention include, as natural polymers, gum arabic, water-soluble soybean polysaccharide, cellulose derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) Body, white dextrin, pullulan,
In synthetic polymers such as enzymatically degraded etherified dextrin,
Polyvinyl alcohol (Polyvinyl acetate hydrolysis rate 6)
5% or more), polyacrylic acid, its alkali metal salt or amine salt, polyacrylic acid copolymer, its alkali metal salt or amine salt, polymethacrylic acid, its alkali metal salt or amine salt, vinyl alcohol / acrylic Acid copolymer and its alkali metal salt or amine salt, polyacrylamide, its copolymer, polyhydroxyethyl acrylate, polyvinylpyrrolidone,
The copolymer, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, alkali metal salt or amine salt thereof, poly-2-acrylamide- Examples thereof include 2-methyl-1-propanesulfonic acid copolymers, alkali metal salts and amine salts thereof. Further, according to the purpose, two or more of these resins can be used in combination. However, the invention is not limited to these examples.

When at least one or more of the water-soluble resins is partially crosslinked to form an overcoat layer on the hydrophilic layer, the crosslinking is carried out by a crosslinking reaction using a reactive functional group of the water-soluble resin. . The cross-linking reaction may be covalent cross-linking or ionic cross-linking.

The crosslinking reduces the tackiness of the surface of the overcoat layer and improves the handleability. However, if the crosslinking proceeds excessively, the overcoat layer changes to lipophilic and it is difficult to remove the overcoat layer on a printing press. Therefore, appropriate partial cross-linking is preferable. The preferred degree of partial crosslinking is 2
When the printing plate is immersed in 5 ° C. water, it takes 30 seconds to 10 seconds.
In minutes, the hydrophilic overcoat layer remains without being eluted, but is eluted in 10 minutes or more.

Examples of the compound used for the crosslinking reaction include known polyfunctional compounds having a crosslinking property, such as polyepoxy compounds, polyisocyanate compounds, polyalkoxysilyl compounds, polyvalent metal salt compounds, polyamine compounds, and aldehyde compounds. And hydrazine. The crosslinking reaction can be accelerated by adding a known catalyst.

Specific examples of known polyfunctional compounds having a crosslinking property include the following compounds.

Specific examples of the polyepoxy compound include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether,
And polycondensates of bisphenols or hydrogenated products thereof with epihalohydrin.

Specific examples of the polyamine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, propylenediamine, polyethyleneimine, and polyamidoamine.

Specific examples of the polyisocyanate compound include tolylene diisocyanate, diphenylmethane isocyanate, liquid diphenylmethane diisocyanate,
Aromatic isocyanates such as polymethylene polyphenyl isocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, cyclohexanephenylene diisocyanate, isopropylbenzene-2,4-diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate and decamethylene diisocyanate; Cyclohexyl diisocyanate, alicyclic diisocyanate such as isophorone diisocyanate,
Further, a polypropylene glycol / tolylene diisocyanate addition reaction product may, for example, be mentioned.

Examples of the silane compound include methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl)- γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldiethoxysilane, 3-chloropropylmethyldimethoxysilane, vinyltris (methylethylketoxime) silane, methyltris (methylethylketoxime) silane , Vinyltriacetoxysilane, etc.

Examples of the titanate compound include tetraethyl orthosilicate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl triactanoyl titanate, isopropyl dimethacryl isostearyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl (dioctyl phosphate) titanate) and isopropyl Tricumylphenyl titanate, isopropyl tri (N-aminoethylaminoethyl) titanate, dicumylphenyloxyacetate titanate, diisostearoylethylene titanate, isopropyltriinstearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris (dioctyl phosphate) titanate , Tetraiso Ropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridisyl phosphite) titanate, tetra (2,2 diallyloxymethyl-1-butyl) bis (ditridecyl phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate Titanates, bis (dioctyl pyrophosphate) oxyacetate titanates, and the like.

Examples of the aldehyde compound include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, glyoxal, glutaraldehyde, terephthalaldehyde and the like.

Examples of the polyvalent metal salt compound include water-soluble salts of metals such as zinc, calcium, magnesium, barium, strontium, cobalt, manganese and nickel.

These crosslinking agents can be used alone or in combination of two or more. Among these crosslinking agents, a particularly preferred crosslinking agent is a water-soluble crosslinking agent, but a water-insoluble one can be used by dispersing it in water with a dispersant.

Particularly preferred combinations of a water-soluble resin and a crosslinking agent include carboxylic acid-containing water-soluble resin / polyvalent metal compound, carboxylic acid-containing water-soluble resin / water-soluble epoxy resin, and hydroxyl group-containing resin / dialdehydes. .

The preferable addition amount of the crosslinking agent is 2 to 2 of the water-soluble resin.
-10% by weight. Within this range, good water resistance can be obtained without impairing the removability of the overcoat layer on a printing press.

In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution application for the purpose of ensuring uniformity of application. Specific examples of such a nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether, and the like. . The proportion of the nonionic surfactant in the total solid content of the overcoat layer is preferably 0.05 to 5% by weight, and more preferably 1 to 3% by weight.

[0072] Dry coating weight of the overcoat layer of the present invention is preferably 0.1~4.0g / m ^2, more preferred range is 0.15~0.25g / m ^2. Within this range, good stain prevention, scratch prevention, fingerprint mark adhesion prevention, and ablation scum generation can be achieved without impairing the removability of the overcoat layer on the printing press.

At least one of the ink receiving layer, hydrophilic layer and overcoat layer of the present invention contains a light-to-heat converting agent having a function of converting light into heat in order to increase sensitivity.

The photothermal conversion agent may be any substance that absorbs light of 700 nm or more, and various pigments and dyes can be used. Examples of pigments include commercially available pigment and color index (CI) handbook, “Latest Pigment Handbook” (edited by The Japan Pigment Technical Association, 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “printing”. Pigments described in "Ink Technology" (CMC Publishing, 1984) can be used.

Examples of the types of pigments include black pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bound pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like.

These pigments may be used without being subjected to a surface treatment, or may be used after being subjected to a surface treatment. The method of surface treatment is a method of surface coating a hydrophilic resin or lipophilic resin,
A method of attaching a surfactant, a method of bonding a reactive substance (for example, silica sol, alumina sol, a silane coupling agent, an epoxy compound, an isocyanate compound, and the like) to the surface of the pigment are considered. The above surface treatment method,
It is described in "Properties and Applications of Metallic Soaps" (Koshobo), "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986). Among these pigments, those that absorb infrared rays are preferred because they are suitable for use in lasers that emit infrared rays. As such a pigment that absorbs infrared rays, carbon black is particularly preferred.

As the pigment to be added to the hydrophilic layer and the overcoat layer of the present invention, particularly, the surface is coated with a hydrophilic resin or silica sol so as to be easily dispersed in a water-soluble or hydrophilic resin and not to impair the hydrophilicity. Carbon black is useful.

The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm. As a method for dispersing the pigment, a known dispersion technique used in the production of ink or toner can be used. As the disperser, an ultrasonic disperser,
Sand mills, attritors, pearl mills, super mills, ball mills, impellers, dispersers, KD mills, colloid mills, dynatrons, three-roll mills, pressure kneaders and the like can be mentioned. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

As the dye, commercially available dyes and literatures (for example, “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, published in 1970,
"Chemical Industry", May 1986, p. 45-51 "Near-infrared absorbing dyes", "Development and market trends of functional dyes in the 1990s", Chapter 2, Section 2.3 (1990), or known dyes described in patents can be used. . Specifically, infrared absorbing dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, polymethine dyes, and cyanine dyes are preferred.

Further, examples of the infrared absorbing dye include, for example, JP-A-58-125246 and JP-A-59-84356.
Cyanine dyes described in JP-A-60-78787, JP-A-58-173696, JP-A-58-173696
181690, methine dyes described in JP-A-58-194595 and the like, JP-A-58-112793,
JP-A-58-224793, JP-A-59-48187
JP-A-59-73996, JP-A-60-5294
No. 0, naphthoquinone dyes described in JP-A-60-63744 and the like, squalilium dyes described in JP-A-58-112792 and the like, British Patent 434,8
No. 75, and US Pat. No. 4,756,9.
No. 93, a cyanine dye described in U.S. Pat. No. 4,973,572, a dye described in JP-A-10-268512, and a phthalocyanine compound described in JP-A-11-235883.

As a dye, US Pat. No. 5,156,
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645 (US Pat. No. 4,327,169)
Described in JP-A-58-18.
No. 1051, No. 58-220143, No. 59-413
No. 63, No. 59-84248, No. 59-84249
Pyrylium compounds described in JP-A-59-146063 and JP-A-59-146061;
Cyanine dyes described in U.S. Pat. No. 2,216,146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-135514 and 5-19702.
Nos. 4,059,098, 4,098,098, 4,098,097, and 3,087,098. Also preferred are pyrylium compounds described in Japanese Patent Application Publication No. JP-A-2002-209, Epolite III-178, Epolite III-130, Epolite III-125 and the like. Among these, a particularly preferred dye to be added to the overcoat layer and the hydrophilic layer is a water-soluble dye, and specific examples are listed below by structural formulas.

[0082]

Embedded image

[0083]

Embedded image

The dye used in the ink receiving layer of the present invention may be the above-mentioned infrared absorbing dye, but is preferably a more lipophilic dye. More preferred dyes include the dyes exemplified below.

[0085]

Embedded image

[0086]

Embedded image

The addition ratio of the photothermal conversion agent is preferably 1 to 50% by weight of the solid content of the hydrophilic layer in the hydrophilic layer, 2 to 50% by weight of the solid content of the overcoat layer in the overcoat layer, and 2 to 50% by weight in the ink receiving layer. , 20 of the solid content of the ink receiving layer
% By weight or less is preferred. Within these ranges, good sensitivity can be obtained without impairing the film strength of each layer.

The heat-sensitive lithographic printing plate of the present invention forms an image by heat. Specifically, direct image-like recording using a thermal recording head or the like, scanning exposure using an infrared laser, high-intensity flash exposure such as a xenon discharge lamp, or infrared lamp exposure is used. Exposure with a solid-state high-output infrared laser such as a laser or a YAG laser is preferable. The image-exposed printing plate of the present invention can be mounted on a printing press without further processing. When printing is started using the ink and fountain solution, the overcoat layer is removed by the fountain solution and at the same time the hydrophilic layer on the exposed part is also removed, and the ink is deposited on the ink receiving layer below and printing starts. Is done.

[0089]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 [Preparation of Aluminum Substrate] 0.01% by weight of copper, 0.03% by weight of titanium,
JI containing 0.3% by weight of iron and 0.1% by weight of silicon
A roll of a 0.24 mm-thick sheet of SA1050 aluminum material was converted to a 400 mesh pumice stone (Kyoritsu Ceramics) 20
The surface was sand-grained using a weight-% aqueous suspension and a rotating nylon brush (6,10-nylon), and then thoroughly washed with water. This was immersed in a 15% by weight aqueous sodium hydroxide solution (containing 4.5% by weight of aluminum), etched so that the amount of aluminum dissolved was 5 g / m ² , and washed with running water. Further, the mixture is neutralized with a 1% by weight nitric acid aqueous solution, and then a 0.7% by weight nitric acid aqueous solution (aluminum 0.5
Weight%), the voltage at the time of anode was 10.5 V, the voltage at the time of cathode was 9.3 V, and the rectangular wave alternating waveform voltage (current ratio r = 0.90,
Was subjected to electrolytic surface roughening treatment in a quantity of anode electricity of 160C / dm ² current waveform) using the disclosed in Japanese Example No. Sho 58-5796. After washing with water, the substrate was immersed in a 10% by weight aqueous solution of sodium hydroxide at 35 ° C., etched so that the amount of aluminum dissolved was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% by weight aqueous sulfuric acid solution at 50 ° C., desmutted, and washed with water. Furthermore, a 20% by weight aqueous solution of sulfuric acid at 35 ° C. (containing 0.8% by weight of aluminum)
A porous anodic oxide film forming treatment was performed using a direct current in the inside. That is, electrolysis is performed at a current density of 13 A / g / m ² and the anodic oxide film weight is 2.7 g by adjusting the electrolysis time.
/ M ² . After washing the support, the support was immersed in a 0.2% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds.
Washed and dried. The amount of silicate attached was 5 mg / m ^{2 as the} amount of silicon measured by X-ray fluorescence analysis. The aluminum substrate obtained as described above had a reflection density of 0.30 and a center line average roughness of 0.58 μm as measured by a Macbeth RD920 reflection densitometer.

[Application of Ink Receiving Layer] On the above support,
An ink receiving layer coating solution A-1 having the following composition
Apply with a K6 bar to 1.25 ml / m ² ,
Heat and dry at 0 ° C for 1 minute, dry coating amount 0.45g / m
² ink receiving layers were obtained. Ra on the surface of the ink receiving layer was 0.56 μm.

(Ink receiving layer coating solution A-1) Epicoat 1009 (manufactured by Yuka Shell Epoxy) 0.8 g Epicoat 1001 (manufactured by Yuka Shell Epoxy) 0.2 g Light-to-heat conversion agent (the IR -24)) 0.2 g Methyl ethyl ketone 2 g Propylene glycol monomethyl ether 23 g

[Coating of hydrophilic layer] On the ink receiving layer thus provided, the following hydrophilic layer coating solution B-1 was applied with a K6 bar, dried at 100 ° C for 1 minute, and dried and applied to the hydrophilic layer. A heat-sensitive lithographic printing plate having an amount of 0.39 g / m ² was obtained. Ra on the surface of the hydrophilic layer was 0.54 μm.

(Hydrophilic layer coating solution B-1) Methanol silica (manufactured by Nissan Chemical Industries, Ltd .: silica particle diameter: 10 to 20 nm, colloid comprising methanol solution containing 30% by weight) 3 g Polyacrylic acid (weight average molecular weight: 250,000) 5% by weight methanol solution 2 g Methyl lactate 1 g Methanol 17.53 g

[Coating of Overcoat Layer] An overcoat layer coating solution OC-1 having the following composition was coated on the hydrophilic layer by K6
The composition was coated with a bar and dried at 100 ° C. for 90 seconds to prepare a heat-sensitive lithographic printing plate having an overcoat layer having a dry coating weight of 0.22 g / m ² .

(Coating solution OC-1 for overcoat layer) Aqueous solution containing 28% by weight of gum arabic 1.5g Photothermal conversion agent (the above (IR-10)) 0.042g Polyoxyethylene nonylphenyl ether (Aqueous solution containing 10% by weight) ) 0.168g ion exchange water 22g

[Plate Making and Printing Evaluation] The above heat-sensitive lithographic printing plate was prepared by using a Trendsetter (4) made by Creo.
(A plate setter equipped with a 830 nm semiconductor laser of 0 W) at an energy of 200 mJ / cm ² . The exposed original plate was attached without further processing to a printing machine Lithrone manufactured by Komori Corporation, and a plate etch solution EU-3 (manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol (volume ratio 1 /
Using a fountain solution consisting of 99/10) and Geos G black ink manufactured by Dainippon Ink and Chemicals Co., Ltd., the fountain solution and the ink were simultaneously operated, and printing was started by supplying art-coated paper. It was developed on the machine without any problems, and the ink was completely deposited on the fifth printout. The water retention was good, and no stain was generated from the start of printing, and printing was completed on 20,000 sheets.

Example 2 A substrate obtained by omitting the immersion treatment in the sodium silicate solution from the production process of the aluminum substrate of Example 1 was used as a support. The amount of the anodic oxide film was 2.7 g / m ² , and the center line average roughness Ra was 0.58 μm. An ink receiving layer coating solution A-2 having the following composition was coated on this substrate in an amount of 11.25 m.
The mixture was applied with a K6 bar to 1 / m ² and heated and dried at 100 ° C. for 1 minute to obtain an ink receiving layer having a dry coating amount of 0.45 g / m ² . Ra on the surface of the ink receiving layer is 0.56 μm
Met.

(Ink receiving layer coating liquid A-2) Epicoat 1009 (manufactured by Yuka Shell Epoxy Co., Ltd.) 1.0 g Light-to-heat converting agent (the above (IR-24)) 0.2 g Methyl ethyl ketone 2 g Propylene glycol monomethyl ether 23 g

On the ink receiving layer, the following hydrophilic layer coating solution B-2 was applied with a K6 bar, dried at 100 ° C. for 1 minute, and dried with a hydrophilic layer in an amount of 0.39 g / m ² for heat-sensitive lithographic printing. An original plate was obtained. Ra on the surface of the hydrophilic layer was 0.55 μm. (Hydrophilic layer coating solution B-2) Methanol silica (Nissan Chemical: same as in Example 1) 3.33 g Methyl lactate 1 g Methanol 19.8 g

The same overcoat layer as in Example 1 was applied on the hydrophilic layer to obtain a heat-sensitive planographic printing plate. The dry coating weight of the overcoat layer was 0.22 g / m ² . Next, when exposed and developed on a machine in the same manner as in Example 1, the ink was completely deposited within 15 prints, the water retention was good, and no stain was generated from the start of printing. It finished with 10,000 copies.

Example 3 A hydrophilic layer and an overcoat layer were applied in the same manner as in Example 2 except that the ink receiving layer coating solution A-3 having the following composition was used instead of the ink receiving layer of Example 2. A lithographic printing plate was obtained. The dry coating amount of the ink receiving layer is 0.45 g / m ² ,
Ra is 0.54 μm, Ra on the surface of the hydrophilic layer is 0.52 μm
Met.

(Ink receiving layer coating liquid A-3) Epicoat 1009 (manufactured by Yuka Shell Epoxy Co., Ltd.) 0.6 g Polymethyl methacrylate (weight average molecular weight 12,000) 0.4 g Light-to-heat conversion agent (the above-mentioned (IR -24)) 0.2 g Methyl ethyl ketone 2 g Propylene glycol monomethyl ether 23 g

Next, when exposure and printing were performed in the same manner as in Example 2, on-press development was possible without any problem. The plate surface exposure energy was 160 mJ / m ² as the optimum exposure amount, and the ink was completely deposited within 5 prints. The water retention was good and no stain was generated from the start of printing, and printing was completed on 20,000 sheets.

Example 4 Example 1 was repeated except that the following overcoat layer coating solution OC-2 was used in place of the overcoat layer coating solution of Example 1.
In the same manner as in the above, a heat-sensitive planographic printing plate was prepared.

(Overcoat Layer Coating Solution OC-2) Polyacrylic acid (weight average molecular weight: 25,000) 1.0 g Calcium acetate 0.12 g Light-to-heat converter ((IR-10)) 0.4 g Polyoxyethylene Nonylphenyl ether (aqueous solution containing 10% by weight) 0.4 g Deionized water 75.3 g

This lithographic printing plate was prepared in the same manner as in Example 1,
Exposure at 00 mJ / m ² produced a vivid faded image. Next, it was mounted on a printing press and developed on the press in the same manner as in Example 1, and printing was performed. As a result, the ink was completely deposited within 5 printouts. The water retention was good and no stain was generated from the start of printing, and 20,000 sheets were printed.

Comparative Example 1 A planographic printing plate was prepared in the same manner as in Example 1 except that the conditions for brush surface roughening and electrolytic surface roughening of the aluminum substrate of Example 1 were changed and a substrate having Ra of 0.45 μm was used. An original plate was produced. Ra after application of the ink receiving layer was 0.42 μm, and Ra after application of the hydrophilic layer was 0.38 μm. Next, this comparative original plate was exposed in the same manner as in Example 1, developed on a press, and printed. As a result, the plate surface exposure energy was 180 mJ / m ^{2, which} was the optimum exposure amount. In the printing under these conditions, the ink was completely deposited within 5 prints and good ink receptivity was exhibited, but the water retention was poor, and the non-image area was stained when 5000 sheets were printed on art-coated paper. Occurred.

Comparative Example 2 The bar for coating the ink receiving layer in Example 1 was changed from K6 bar to K10 bar to reduce the amount of the coating liquid to 19.5 m.
1 / m ^2, and the dry coating amount of the ink receiving layer is 0.76 g
/ M ² . As a result, Ra on the surface of the ink receiving layer
Was 0.44 μm. The application of the hydrophilic layer and the overcoat layer was performed in the same manner as in Example 1 to prepare a lithographic printing original plate for comparison. Ra of surface after application of hydrophilic layer is 0.42μ
m.

The original plate for comparison was exposed to light in the same manner as in Example 1, developed on a press, and printed. As a result, the optimum exposure amount was 180 mJ / m ^{2 for} plate surface exposure energy. In the printing under these conditions, the ink was completely deposited within 5 prints,
The water retention was poor, and stains occurred on the non-image area when 8,000 sheets were printed on art-coated paper.

[0111]

According to the present invention, plate making can be performed by scanning exposure based on digital signals, and after exposure, printing can be performed by directly attaching to a printing machine without performing processing.
A heat-sensitive lithographic printing plate having good stain resistance and printing durability can be provided.

Continued on front page F-term (reference) 2H025 AA12 AB03 AC08 AD01 BH03 BJ00 CC11 CC20 DA18 EA10 FA21 2H096 AA07 BA20 CA03 CA05 EA04 EA23 2H114 AA04 AA22 AA24 AA27 BA01 DA04 DA15 DA25 DA26 DA46 DA52 DA55 DA11 FA03 EA01 GA01 GA06 GA08 GA09 GA27 GA34 GA36 GA38

Claims (2)

[Claims] 1. An aluminum substrate grained and anodized on its surface, (1) an ink receiving layer, and (2) beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium. A heat-sensitive lithographic printing plate having a hydrophilic layer containing, in this order, a colloidal particulate oxide or hydroxide of at least one element selected from iron, vanadium, antimony and a transition metal, the ink receiving layer and A heat-sensitive lithographic printing plate precursor, wherein at least one of the hydrophilic layers contains a photothermal conversion agent, and the center line average roughness Ra of the hydrophilic layer surface is 0.45 μm or more. 2. On the aluminum substrate according to claim 1,
A heat-sensitive lithographic printing plate having, in this order, (1) an ink receiving layer, (2) a hydrophilic layer according to claim 1, and (3) a hydrophilic overcoat layer that can be removed on a printing press, the ink receiving layer being provided. At least one of the layer, the hydrophilic layer and the hydrophilic overcoat layer contains a light-to-heat conversion agent, and the center line average roughness Ra of the hydrophilic layer surface is 0.45 μm or more. Original plate for printing.