JP2003145954A - Heat-sensitive lithographic printing plate master - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive lithographic printing plate master which can be printed by mounting directly in a printer without treating after exposure and in which both a sensitivity and a plate wear resistance are made compatible. SOLUTION: The heat-sensitive lithographic printing plate master comprises (1) an ink acceptive layer, (2) a hydrophilic layer containing a colloidal particle- like oxide or hydroxide of at least one element selected from the group consisting of beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and a transition metal and (3) a hydrophilic overcoating layer having a dry weight of 0.05 to 0.20 g/m<2> on a support in such a manner that at least one of the ink acceptive layer, the hydrophilic layer and the hydrophilic overcoating layer contains a photothermal conversion agent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat-sensitive lithographic printing plate precursor that does not require development. More specifically, it is possible to record an image by infrared laser beam scanning exposure based on a digital signal, and the recorded image can be mounted on a printing machine as it is and printed without undergoing a conventional developing process. The present invention relates to a lithographic printing plate, which has good sensitivity and good printing durability.

[0002]

2. Description of the Related Art Various methods have been proposed for a lithographic printing plate precursor which is image-formed by heat and which can be mounted on a printing machine without treatment. One of the promising methods is an ablation method in which a solid high-power infrared laser such as a semiconductor laser or a YAG laser is used for exposure, and the exposed portion is heated by a photothermal conversion agent to cause decomposition and evaporation. That is, it is a method in which a hydrophilic layer is provided on a lipophilic substrate or a substrate having an lipophilic layer, and the hydrophilic layer is image-wise ablated and removed.

[0004] WO94 / 18005 discloses a printing plate in which a crosslinked hydrophilic layer is provided on an lipophilic laser light absorbing layer and the hydrophilic layer is ablated. This hydrophilic layer is made by cross-linking polyvinyl alcohol with a hydrolyzate of tetraethoxysilicon and contains titanium dioxide particles, and is intended to improve the film strength of the hydrophilic layer. Printing durability is improved by this technique. However, although polyvinyl alcohol has a hydrocarbon group and is not necessarily highly hydrophilic, it occupies 48% by mass of the solid content of the hydrophilic layer. Therefore, it is insufficient in stain resistance and needs further improvement.

WO98 / 40212, WO99 /
In JP 19143 and WO 99/19144, a hydrophilic layer whose main component is a colloid such as silica crosslinked with a crosslinking agent such as aminopropyltriethoxysilane is provided on a substrate coated with an ink receiving layer, A lithographic printing plate precursor that can be mounted on a printing machine without development is disclosed. This hydrophilic layer has as few hydrocarbon groups as possible to enhance the resistance to printing stains, and improves the printing durability by crosslinking the colloid with a crosslinking agent. However, its printing durability is inadequate to several thousand sheets.

A digital direct unprocessed printing plate utilizing ablation can directly make a printing plate from below the plate without interposing a film, and can be mounted on a printing machine as it is for immediate printing. There is a big advantage of rationalization of waste and reduction of waste, but due to the difficulty of the technology without processing, either the stain resistance or printing durability, which is the basis of printing, tends to be impaired, and a technology that achieves both Can be said to be still under development. In the course of such technological development process, JP-A-2001-96938
A) an ink receiving layer containing a photothermal conversion agent,
b) beryllium, magnesium, aluminum, silicon,
Titanium, boron, germanium, tin, zirconium,
By providing a hydrophilic layer formed by applying a solution containing a colloid of an oxide or hydroxide of at least one element selected from iron, vanadium, antimony and a transition metal and a hydrophilic resin, without performing treatment. It can be mounted directly on the printing machine for printing, and has excellent printing durability,
The invention has invented a heat-sensitive lithographic printing plate precursor that hardly causes printing stains. However, these heat-sensitive lithographic printing plate precursors are not sufficiently compatible with both sensitivity and printing durability.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems, and after exposure, it is possible to directly mount on a printing press without performing processing, and print. An object is to provide a heat-sensitive lithographic printing plate precursor having both sensitivity and printing durability.

[0007]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventor has found that the above objects can be achieved by setting the thickness of the overcoat layer within a preferable range, and has reached the present invention. It was done. That is, the present invention is as follows.

1) On a support, (1) an ink receiving layer,
(2) Containing 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 metal. It has a hydrophilic layer and (3) a hydrophilic overcoat layer having a dry weight of 0.05 to 0.20 g / m ² , and at least one of the ink receiving layer, the hydrophilic layer and the hydrophilic overcoat layer is photothermal. A heat-sensitive lithographic printing plate precursor containing a converting agent.

2) The dry weight of the hydrophilic layer is 0.40 g.
/ M ² or more, the heat-sensitive lithographic printing plate precursor as described in 1) above. 3) The heat-sensitive lithographic printing plate precursor as described in 1) above, wherein the hydrophilic overcoat layer contains a resin obtained by partially crosslinking a water-soluble resin.

In the heat-sensitive lithographic printing plate precursor of the present invention,
By providing the overcoat layer, the pressure due to ablation tends to be applied to the hydrophilic layer / ink receiving layer interface, and thus the sensitivity is improved, but if the overcoat layer is applied in an excessively large amount, ablation is suppressed. It was found that the sensitivity was reduced. That is, it is clear that the overcoat layer coating amount has an optimum value.

On the other hand, the higher the coating amount of the hydrophilic layer, the better the printing durability, but the lower the sensitivity. Therefore, since the coating amount of the overcoat layer does not affect the printing durability, it was found that both the sensitivity and the printing durability can be achieved by adjusting the coating amount of the hydrophilic layer and the coating amount of the overcoat layer. Therefore, the dry weight of the overcoat layer in the heat-sensitive lithographic printing plate precursor of the present invention is set to 0.05 to 0.20 g / m ² . If the dry weight of the overcoat layer is less than 0.05, the scratch resistance deteriorates.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The coating amount of the overcoat layer of the heat-sensitive lithographic printing plate precursor of the present invention is 0.05 in terms of dry weight.
To 0.20 g / m ² , preferably 0.08
~ 0.18 g / m ² , more preferably 0.09-0.1
It is in the range of 6 g / m ² . Within the above range, both sensitivity and printing durability can be obtained. The water-soluble resin of the hydrophilic overcoat layer is selected from water-soluble natural polymers and synthetic polymers,
The coated and dried film has a film-forming ability.

Specific examples of the water-soluble resin preferably used in the present invention include natural polymers such as gum arabic, water-soluble soybean polysaccharides and fibrin derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.). , Synthetic polymers such as denatured product thereof, white dextrin, pullulan, enzymatically-decomposed etherified dextrin, polyvinyl alcohol (having a hydrolysis rate of polyvinyl acetate of 65% or more), polyacrylic acid, an alkali metal salt or an amine salt thereof. , Polyacrylic acid copolymer, its alkali metal salt or amine salt, polymethacrylic acid, its alkali metal salt or amine salt, polymethacrylic acid copolymer, its alkali metal salt or amine salt, vinyl alcohol / acrylic acid copolymer Coalesced and its alkali metal salt Amine salts, polyacrylamide, copolymers thereof, polyhydroxyethyl acrylate, polyvinyl pyrrolidone, copolymers thereof, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl -
1-propanesulfonic acid, its alkali metal salt or amine salt, poly-2-acrylamido-2-methyl-1
-Propane sulfonic acid copolymer, its alkali metal salt or amine salt, and the like can be mentioned. In addition, two or more kinds of these resins may be mixed and used depending on the purpose. However, the invention is not limited to these examples.

Further, the overcoat layer of the heat-sensitive lithographic printing plate precursor of the present invention, in order to further improve the scratch resistance of the plate, partially cross-links at least one of the above-mentioned water-soluble resins to form a hydrophilic layer on the hydrophilic layer. It is preferably formed. A suitable degree of partial cross-linking is that when the original plate is immersed in water at 25 ° C., the hydrophilic overcoat layer does not elute and remains water resistant for 30 seconds to 10 minutes. The method of crosslinking the water-soluble resin will be described below. The cross-linking is performed by a cross-linking reaction using the reactive functional group of the water-soluble resin. The cross-linking reaction may be a covalent bond or an ionic bond.

Examples of the compound used in 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. , Hydrazine and the like, and the crosslinking reaction can be promoted by adding a known catalyst. Specific examples of known polyfunctional compounds having crosslinkability 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,
Examples thereof include polycondensates of bisphenols or hydrogenated products thereof and 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,
Polymethylene polyphenyl isocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, cyclohexanephenylene diisocyanate, isopropylbenzene-2,4-diisocyanate, and other aromatic isocyanates, hexamethylene diisocyanate, decamethylene diisocyanate and other aliphatic isocyanates, Alicyclic diisocyanates such as cyclohexyl diisocyanate and isophorone diisocyanate,
Further, a polypropylene glycol / tolylene diisocyanate addition reaction product and the like can be mentioned.

As the silane compound, 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 are tetraethyl orthosilicate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyltoreactanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl (dioctyl phosphate) titanate), and isopropyl. Tricumyl phenyl titanate, isopropyl tri (N-aminoethylaminoethyl) titanate, dicumyl phenyloxyacetate titanate, diisostearoyl ethylene titanate, isopropyl triyne stearoyl titanate, isopropyl tridodecylbenzene sulfonyl titanate, isopropyl tris (dioctyl phosphate) titanate , Tetraiso Ropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridicyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl phosphite titanate, bis (dioctyl pyrophosphate) oxyacetate Titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, etc.

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 cross-linking agents may be used alone or in 2
It is possible to use a mixture of two or more species. Among these cross-linking agents, a particularly preferable cross-linking agent is a water-soluble cross-linking agent, but a non-water-soluble cross-linking agent can be used by dispersing it in water with a dispersant.

Particularly preferred combinations of the water-soluble resin and the crosslinking agent include carboxylic acid-containing water-soluble resin / polyvalent metal compound, carboxylic acid-containing water-soluble resin / water-soluble epoxy resin, hydroxyl group-containing resin / dialdehydes. . The suitable addition amount of the cross-linking agent is 2 to 10 mass% of the water-soluble resin. Within this range, good water resistance can be obtained without impairing the removability of the overcoat layer on the printing machine.

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

The hydrophilic layer used in the heat-sensitive lithographic printing plate precursor of the present invention is a layer that is insoluble in fountain solution in lithographic printing using fountain solution and ink, and is beryllium, magnesium, aluminum or silicon. , A solution containing colloidal particulate oxide or hydroxide of at least one element selected from titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals, and polyacrylic acid. It is formed. Among the elements constituting the colloidal particulate oxide or hydroxide used in the present invention, aluminum, silicon, titanium and zirconium can be mentioned as particularly preferable ones.

The size of the colloid used in the present invention is
The silica is preferably spherical and has a particle size of 5 to 100 nm. Spherical particles with a particle size of 10 to 50 nm are 50 to 400 nm
It is also possible to use a pearl-neck-shaped colloid that is continuous in length. Feather-like particles of 100 nm × 10 nm such as aluminum oxide or hydroxide colloid are also effective.

These colloids can be prepared by various known methods such as hydrolysis of halides or alkoxy compounds of the above elements or condensation of hydroxides. For example,
It is also possible to directly apply a hydrolysis / condensation reaction from di, tri and / or tetraalkoxysilane in the presence of an acid catalyst to prepare and apply a sol. When this sol is applied, a stronger hydrophilic three-dimensional crosslinked film is obtained. As the colloidal dispersion liquid, a commercially available product such as Nissan Chemical Industries Ltd. may be selected and used.

The hydrophilic layer of the present invention may contain a hydrophilic resin. As the hydrophilic resin, those having a hydrophilic group such as hydroxyl, carboxyl, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl and carboxymethyl are preferable.

Specific hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and their Na salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, Polyacrylic acids and salts thereof, polymethacrylic acids and salts thereof, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers of hydroxypropyl acrylate and Copolymers, homopolymers and copolymers of hydroxybutyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and homopolymers and copolymers of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide with a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight. , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, and the like.

These hydrophilic resins are used together with the colloid, and the addition ratio is as follows when the hydrophilic resin is water-soluble.
The total solid content of the hydrophilic layer is preferably 40% by mass or less, and in the case of a non-water-soluble hydrophilic resin, the total solid content is preferably 20% by mass or less.

In the hydrophilic layer of the present invention, in addition to the above colloid and hydrophilic resin, a crosslinking agent that promotes crosslinking of the colloid may be added. Examples of the cross-linking agent for such colloids include initial hydrolysis-condensation products of tetraalkoxysilane, metal chelate compounds such as titanium bis (triethanolamine) diisopropoxide, trialkoxysilylpropyl-
N, N, N-trialkylammonium halides or aminopropyltrialkoxysilanes are preferred. The addition ratio is preferably 5% by mass or less of the total solid content of the hydrophilic layer.

The hydrophilic resin may be used as it is, but in order to enhance printing durability, it may be used together with a cross-linking agent of a hydrophilic resin other than colloid, if necessary. As such a cross-linking agent, formaldehyde, glyoxal, polyisocyanate and tetraalkoxysilane initial hydrolysis / condensation product, titanium bis (triethanolamine)
Examples thereof include metal chelate compounds such as diisopropoxide, dimethylol urea and hexamethylol melamine.

The hydrophilic layer containing each of the above components is provided by coating a solution prepared by dissolving or dispersing each component in a solvent. As the main solvent for the hydrophilic layer coating liquid, water and low boiling point alcohols such as methanol, ethanol and propanol are used alone or as a mixture. The hydrophilic layer of the present invention may further contain well-known fluorine-based surfactants, silicon-based surfactants, polyoxyethylene-based surfactants, etc. in order to improve the surface state of coating. .

The coating amount of the hydrophilic layer of the present invention, preferably the dry weight, 0.40 g / m ² or more, more preferably in the range of 0.40~1.0g / m ^2. By adjusting the coating amount of the above overcoat layer, the sensitivity is excellent, the ablation is good, and the printing durability is good.

The ink-receiving layer of the heat-sensitive lithographic printing plate precursor according to the invention contains a lipophilic organic polymer soluble in a solvent capable of forming a film. Useful organic polymers include polyester, polyurethane, polyurea, polyimide,
Polysiloxane, polycarbonate, phenoxy resin,
Epoxy resin, phenol-formaldehyde resin, alkylphenol-formaldehyde resin, polyvinyl acetate, acrylic resin and its copolymer, polyvinyl phenol, polyvinyl halogenated phenol, methacrylic resin and its copolymer, acrylamide copolymer, methacrylamide copolymer , Polyvinyl formal, polyamide, polyvinyl butyral, polystyrene, cellulose ester resin, polyvinyl chloride, polyvinylidene chloride and the like.

Among these, as a more preferable compound, a resin having a hydroxyl group, a carboxyl group, an epoxy group, a sulfonamide group or a trialkoxysilyl group in a side chain is excellent in adhesiveness to a substrate or an upper hydrophilic layer, It is desirable because it is easily cured with a crosslinking agent in some cases. In addition, 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.

Other 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-Br), salicylic acid, a novolak resin and a resole resin which are condensed with formaldehyde such as phloroglucinol, and a condensed resin of the above-mentioned phenol compound and acetone are useful.

Other preferable polymer compounds include copolymers having the following monomers (1) to (12) as the constitutional units and usually having a molecular weight of 10,000 to 200,000. (1) Acrylamides, methacrylamides, acrylic esters, methacrylic esters and hydroxystyrenes having an aromatic hydroxyl group, such as N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacryl. Amide, o
-, M- and p-hydroxystyrene, o-, m- and p-hydroxyphenyl acrylate or methacrylate, (2) acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl 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, acrylate-2 -(Substituted) acrylic acid esters such as chloroethyl, 4-hydroxybutyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, (4) methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, 4-hydroxybutyl methacrylate, (Substituted) methacrylic acid esters such as glycidyl methacrylate and N-dimethylaminoethyl methacrylate,

(5) Acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N
-Hydroxyethyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N
-Phenyl methacrylamide, N-benzyl acrylamide, N-benzyl methacrylamide, N-nitrophenyl acrylamide, N-nitrophenyl methacrylamide, N-ethyl-N-phenyl acrylamide and N
Acrylamide or methacrylamide such as -ethyl-N-phenylmethacrylamide,

(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, methylstyrene and chloromethylstyrene, ( 9)
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)) Naphtyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Methacrylamides such as phenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, and o-aminosulfonylphenyl acrylate, m-amino. Sulfo sulfonyl phenyl acrylate,
p-aminosulfonylphenyl acrylate, 1- (3
-Aminosulfonylphenylnaphthyl) acrylates and other unsaturated sulfonamides such as acrylic acid esters, o-aminosulfonylphenyl methacrylate, m
-Unsaturated sulfonamides such as methacrylic acid esters such as aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3-aminosulfonylphenylnaphthyl) methacrylate.

The ink receiving layer of the present invention further comprises a crosslinking agent,
If necessary, an adhesion aid, a colorant, inorganic or organic fine particles, a coating surface condition improving agent, and a plasticizer can be added. In addition, the ink receiving layer may contain a photothermal conversion agent for increasing sensitivity and a heat-coloring or decoloring additive for forming a printout image after exposure.

As specific cross-linking agents for cross-linking organic polymers, diazo resin, aromatic azide compound, epoxy resin, isocyanate compound, blocked isocyanate compound, initial hydrolysis condensate of tetraalkoxysilicon, metal chelate compound [titanium di Isopropoxide bis (2,4-pentadionate), aluminum tris (2,4-pentadionate), zirconium tetrakis (2,4-pentadionate), etc.], glyoxal, aldehyde compounds and methylol compounds You can As the adhesion aid, the above-mentioned diazo resin excels in adhesion to the substrate and the hydrophilic layer, but in addition to this, a silane coupling agent, an isocyanate compound, and a titanium coupling agent are also useful.

Usual dyes and pigments are used as the colorant, but especially rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, oxazine 4 perchlorate, quinizarine,
2- (α-naphthyl) -5-phenyloxazole and coumarin-4 can be mentioned. Specifically as other dyes,
Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black B
Y, Oil Black BS, Oil Black T-505
(Above, manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255
5), methyl violet (CI42535), ethyl violet, methylene blue (CI52015), patent pure blue (Sumitomo Sangoku Chemical Co., Ltd.), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4
-P-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide and other triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based dyes or JP-A-62-62 -293247, JP-A-9-1792
The dyes described in Japanese Patent No. 90 can be mentioned. When the dye is added to the ink receiving layer, it is usually about 0.02 to 10% by mass based on the total solid content of the receiving layer,
More preferably, it is about 0.1 to 5 mass%.

Further, a fluorine type surfactant and a silicon type surfactant which are well known compounds as a coating surface condition improving agent can be used. Specifically, a surfactant having a perfluoroalkyl group or a dimethylsiloxane group is useful by adjusting the coated surface.

As the inorganic or organic fine particles which can be used in the present invention, colloidal silica or colloidal aluminum having a particle size of 10 nm to 100 nm, and further inert particles having a particle size larger than these colloids, for example, silica particles, surface-hydrophobicized. Examples thereof include silica particles, alumina particles, titanium dioxide particles, other heavy metal particles, clay and talc. Addition of these inorganic or organic fine particles to the ink receiving layer has the effects of improving the adhesiveness with the hydrophilic layer above and increasing the printing durability in printing. The addition ratio of these fine particles in the ink receiving layer is 80% by mass or less, preferably 40% by mass or less, of the total amount.

If necessary, a plasticizer is added to the ink receiving layer of the present invention 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 polymers are used.

Further, in the ink receiving layer of the present invention, it is preferable to add a color-forming or decolorizing compound in order to make the image area and the non-image area clear when exposed. For example,
Leuco dye (leucomalachite green, along with thermal acid generators such as diazo compounds and diphenyliodonium salts)
Leuco crystal violet, crystal violet lactone, etc.) and PH discoloring dyes (eg, ethyl violet, Victoria Poor Blue BOH, etc.)
Is used. In addition, a combination of an acid color dye and an acidic binder as described in EP897134 is also effective. In this case, the bond in the association state forming the dye is broken by heating, the lactone body is formed, and the color changes from colorless to colorless. The addition ratio of these coloring or decoloring system is 10% by mass based on the total solid content in the receiving layer.
It is preferably 5% by mass or less.

Solvents for coating the ink receiving layer include 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, ethylene glycol monomethyl monoacetate, methyl lactate, ethyl lactate,
Gamma-butyrolactone, etc.), amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone, etc.) and the like can be used. These solvents are used alone or in a mixed state. When the coating liquid is prepared, the concentration of the ink receiving layer constituent components (total solid content including additives) in the solvent is preferably 1 to 50% by mass. In addition, the coating can be formed not only from the above organic solvent but also from an aqueous emulsion. In this case, the concentration is preferably 5% by mass to 50% by mass.

The weight of the ink-receiving layer of the present invention after coating and drying is not particularly limited, but when it is provided on a metal plate, it also serves as a heat insulating layer, so 0.1 g / m ² or more is used. preferable. It is more preferably 0.2 g / m ² or more. When a lipophilic plastic film is used as the substrate, the ink receiving layer only needs to be able to function as an adhesive layer with the upper layer, so that the coating amount thereof may be smaller than that of the metal plate. It is preferably at least 05 g / m ² .

In the present invention, a photothermal conversion agent having a function of absorbing infrared rays to generate heat is added to at least one layer of the ink receiving layer, the hydrophilic layer and the overcoat layer in order to enhance sensitivity to infrared rays. .

The photothermal conversion agent may be any substance as long as it absorbs light of 700 nm or more, and various pigments and dyes can be used. As pigments, commercially available pigments and color index (CI) handbook, "Latest pigment handbook" (edited by Japan Pigment Technology Association, 1977), "Latest pigment application technology" (CMC Publishing, 1986), "Printing" The pigments described in "Ink Technology" (CMC Publishing, 1984) can be used.

Examples of pigments include black pigments, brown pigments, red pigments, violet pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments. , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.

These pigments may be used without surface treatment or may be used after surface treatment. The surface treatment method is a method of surface-coating a hydrophilic resin or a lipophilic resin,
A method of attaching a surfactant, a method of binding a reactive substance (for example, silica sol, alumina sol, a silane coupling agent, an epoxy compound, an isocyanate compound, etc.) to the pigment surface can be considered. The above surface treatment method,
It is described in “Properties and Applications of Metal Soap” (Koshoubo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Among these pigments, those that absorb infrared rays are preferable because they are suitable for use in a laser that emits infrared rays. Carbon black is particularly preferable as such an infrared absorbing pigment.

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

The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm, 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 ink production, toner production or the like can be used. As the disperser, an ultrasonic disperser,
Sand mill, attritor, pearl mill, super mill, ball mill, impeller, desperser, KD mill, colloid mill, dynatron, three roll mill, pressure kneader and the like can be mentioned. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

As dyes, commercially available dyes and literatures (for example, "Handbook of Dyes" edited by the Society of Organic Synthetic Chemistry, published in 1945,
"Chemical Industry" May 1986 issue P. Known dyes described in "Near-infrared absorbing dyes" of 45 to 51, "Development and market trends of 90's functional dyes", Chapter 2, Section 2.3 (1990) CMC) or 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, quinoneimine dyes, polymethine dyes, and cyanine dyes are preferable.

Further, examples of the infrared absorbing dye include, for example, JP-A-58-125246 and JP-A-59-84356.
And the cyanine dyes described in JP-A-60-78787, JP-A-58-173696, and JP-A-58-
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, squarylium dyes described in JP-A-58-112792 and the like, British Patent 434,8
No. 75, cyanine dyes and US Pat. No. 4,756,9
93, dyes described in U.S. Pat. No. 4,973,572, dyes described in JP-A-10-268512, and phthalocyanine compounds described in JP-A-11-235883.

Further, as a dye, US Pat. No. 5,156,
The near-infrared absorption sensitizer described in US Pat. No. 938 is also preferably used, and the substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, JP-A-57-1.
42645 (US Pat. No. 4,327,169)
Trimethine thiapyrylium salt described in JP-A-58-18
No. 1051, No. 58-220143, No. 59-413
63, 59-84248, 59-84249.
Nos. 59-146063 and 59-146061, and pyrylium compounds disclosed in JP-A-59-46061.
-216146, cyanine dyes, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and Japanese Patent Publication Nos. 5-13514 and 5-19702.
Pyrylium compounds described in Japanese Patent Publication No. Epolite III-178, Epolite III-130, Epolite III-125 and the like manufactured by Eporin Co. are also preferably used. Of these, water-soluble dyes are particularly preferable dyes to be added to the overcoat layer and the hydrophilic layer, and specific examples thereof are listed below by structural formulas.

[0059]

[Chemical 1]

[0060]

[Chemical 2]

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

[0062]

[Chemical 3]

[0063]

[Chemical 4]

In the hydrophilic layer, the addition ratio of the photothermal conversion agent is 1 to 50% by mass, preferably 2 to 20% by mass of the solid content. In the overcoat layer, 1 to 70 mass% of solid content,
Preferably 2 to 50% by mass, when the photothermal conversion agent is a dye,
It is particularly preferably 2 to 30% by mass, and particularly preferably 20 to 50% by mass when the photothermal conversion agent is a pigment. The proportion of the photothermal conversion agent added to the ink receiving layer is preferably 20% by mass or less, and particularly preferably 15% by mass or less, based on the total solid content of the ink receiving layer. Within these ranges, good sensitivity can be obtained without impairing the film strength of each layer.

As the support used in the present invention, a dimensionally stable plate is used. Paper, paper laminated with lipophilic plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, nickel, stainless steel plate, etc.),
Plastic film (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), the above metals are laminated or vapor deposited. Included is paper or plastic film, etc.

A preferred substrate is a polyethylene terephthalate film, a polycarbonate film, aluminum or a steel plate, or an aluminum or steel plate laminated with a lipophilic plastic film.

The aluminum plate used in the present invention is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, and further, a thin film of aluminum or an aluminum alloy laminated with plastic. Is. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium,
There are chromium, zinc, bismuth, nickel, titanium, etc. The content of foreign elements in the alloy is at most 10% by weight. Further, the aluminum plate may be an aluminum ingot made by the DC casting method or an ingot made by the continuous casting method. However, as the aluminum plate applied to the present invention, an aluminum plate of a publicly known and publicly known material can be appropriately used.

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

Prior to using the aluminum plate, it is preferable to perform surface treatment such as surface roughening and anodic oxidation. The surface treatment facilitates ensuring the adhesiveness to the ink receiving layer.

The surface roughening treatment of the aluminum plate is carried out by various methods, for example, a method of mechanically roughening the surface, a method of electrochemically melting and roughening the surface, and a method of chemically roughening the surface. It is carried out by a method of selective dissolution. As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. As a chemical method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A-54-31187 is suitable. Further, as an electrochemical graining method, there is a method of performing alternating current or direct current 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 also be used.

The surface roughening by the method as described above is carried out when the center line average roughness (Ra) of the surface of the aluminum plate is 0.2 to 1.
It is preferably applied in the range of 0 μm. The roughened aluminum plate is optionally subjected to alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide, etc., and further neutralized, and then anodized to enhance abrasion resistance if desired. Processing is performed.
As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used, and generally sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions of anodization cannot be unconditionally specified because they vary depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80% by mass.
Solution temperature is 5 to 70 ° C., a current density of 5 to 60 A / dm ^2,
A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. The amount of oxide film formed is 1.0 to 5.
0 g / m ^2, it is particularly preferably 1.5 to 4.0 g / m ^2.

The support used in the present invention may be the substrate which has been subjected to the above-mentioned surface treatment and has an anodized film as it is, but it is necessary for further improvement of the adhesiveness with the upper layer, the heat insulating property and the like. According to Japanese Patent Application No. 2000-65219
No. 2000-143387 or Japanese Patent Application No. 2000-143387, the micropore expansion treatment of the anodized film, the micropore sealing treatment, and the surface hydrophilization treatment immersed in an aqueous solution containing a hydrophilic compound are appropriately selected. Can be done by Suitable hydrophilic compounds for the above-mentioned hydrophilic treatment include polyvinylphosphonic acid, compounds having sulfonic acid groups, saccharide compounds, citric acid, alkali metal silicates, potassium zirconium fluoride, phosphates / inorganic fluorine compounds, etc. Can be mentioned.

The heat-sensitive lithographic printing plate precursor of the invention is image-formed by heat. Specifically, direct image-like recording with a thermal recording head, scanning exposure with an infrared laser, high-illuminance flash exposure with a xenon discharge lamp, infrared lamp exposure, etc. are used, but a semiconductor that emits infrared rays with a wavelength of 700 to 1200 nm. Exposure with a solid-state high-power infrared laser such as a laser or a YAG laser is preferable. The image-exposed printing master plate of the present invention can be mounted on a printing machine without further treatment. Alternatively, the printing original plate may be attached to the printing machine, laser exposure may be performed on the printing machine, and printing may be performed as it is.

[0074]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. Examples 1 to 4 and Comparative Examples 1 to 3 (Production of Substrate) 0.01% by mass of aluminum, 0.01% by mass of copper, 0.03% by mass of titanium and 0.3% of iron on 99.5% by mass of aluminum.
JIS A10 containing 10% by mass and 0.1% by mass of silicon
50 aluminum material thickness 0.24mm rolled plate, 40
A 20% by mass aqueous suspension of 0-mesh pumicetone (manufactured by Kyoritsu Kiln Co., Ltd.) and a rotating nylon brush (6,10-nylon) were used to grain the surface of the suspension, followed by thorough washing with water. This was immersed in a 15 mass% sodium hydroxide aqueous solution (containing 4.5 mass% of aluminum) to perform etching so that the amount of aluminum dissolved was 5 g / m ² , and then washed with running water. Further, it was neutralized with 1% by mass of nitric acid, and then neutralized.
7 mass% nitric acid aqueous solution (containing 0.5 mass% aluminum)
Among them, a rectangular wave alternating waveform voltage having an anode voltage of 10.5 V and a cathode voltage of 9.3 V (current ratio r = 0.90, current waveform described in Japanese Patent Publication No. 58-5796). Was subjected to electrolytic surface roughening treatment at an amount of electricity of 160 clones / dm ^{2 at} the time of an anode. After washing with water, 10% by mass at 35 ° C
It was immersed in a sodium hydroxide aqueous solution, 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 mass sulfuric acid aqueous solution at 50 ° C., desmutted, and then washed with water.

Further, a porous anodic oxide film forming treatment was carried out by using a direct current in a 20% by mass aqueous solution of sulfuric acid (containing 0.8% by mass of aluminum) at 35 ° C. That is, electrolysis was performed at a current density of 15 A / dm ² , and the weight of the anodized film was adjusted to 3.7 g / m ² by adjusting the electrolysis time, followed by washing with water and drying. The center line average roughness (Ra) of the aluminum substrate obtained as described above was 0.53 μm.

(Formation of Ink Receiving Layer) A coating solution for ink receiving layer having the following composition having a dry coating weight of 0.42 was formed on the above substrate.
It was applied so as to be g / m ² and dried at 100 ° C. for 1 minute to form an ink receiving layer.

[0077] (Coating liquid formulation for ink receiving layer) Epicoat 1009 8.0 g (Bisphenol A-epichlorohydrin epoxy resin,       Japan Epoxy Resin Co., Ltd.) Epicoat 1001 2.0g (Bisphenol A-epichlorohydrin epoxy resin,   Japan Epoxy Resin Co., Ltd.) Infrared absorbing dye (A) below 2.0g Ethylene glycol monomethyl ether 165 g Methyl ethyl ketone 85 g

[0078]

[Chemical 5]

(Formation of hydrophilic layer) 0.1 g of polyacrylic acid (weight average molecular weight 250,000) and methanol silica (manufactured by NISSAN CHEMICAL: 10 nm to 20 nm of silica particles are used).
3 g of a colloid consisting of a methanol solution containing mass%)
And a solution of 16 g of methanol and 1 g of methyl lactate on the above ink receiving layer in a dry coating weight of 0.40 g / m 2.
^It was applied so as to be ^2, and dried at 100 ° C. for 1 minute to form a hydrophilic layer to obtain a heat-sensitive lithographic printing plate precursor.

(Preparation of heat-sensitive lithographic printing plate precursor)
Overcoat layer coating liquid 1 having the following composition on the hydrophilic layer
Are coated so that the dry coating weights shown in the table below are obtained,
It was dried at 100 ° C. for 90 seconds to prepare a heat-sensitive lithographic printing plate precursor having an overcoat layer.

[0081] (Overcoat layer coating liquid 1) Gum arabic (28% by mass aqueous solution) 1.5 g 20 g of water

(Evaluation of sensitivity of heat-sensitive lithographic printing plate precursor) Each heat-sensitive lithographic printing plate precursor thus obtained was manufactured by Creo.
Image exposure was carried out by variously changing the exposure energy with a Trendsetter (blade setter equipped with a 40 W 830 nm semiconductor laser). The exposed original plate was directly subjected to no further treatment and mounted on a printing machine Lithlon manufactured by Komori Corporation, and a blade etching solution EU-3 (manufactured by Fuji Photo Film Co., Ltd.) / Water / isopropyl alcohol (volume ratio 1/89 / Using fountain solution consisting of 10) and Dios G black ink manufactured by Dainippon Ink and Chemicals, Inc., the fountain solution and ink were simultaneously operated, and art-coated paper was supplied to start printing. At this time, the minimum exposure energy amount at which the ink completely adhered within the 5th printed sheet and a good printed matter without stain was obtained was defined as the sensitivity. As a result, as shown in the table below, the sensitivity was improved by making the overcoat layer a thin layer.

[0083]

[Table 1]

Example 5 A heat-sensitive lithographic printing plate precursor was prepared in the same manner as in Example 3, except that the coating solution for the overcoat layer was changed to the following composition.
Then, as in Example 3, the exposure energy was 180 mJ.
When exposure and printing were carried out at / cm ² , the ink was completely inked on the 5th printed sheet, and 20,000 good printed matters without stain were obtained thereafter.

[0085] (Overcoat layer coating liquid 2) Gum arabic (28 mass% aqueous solution) 1.5 g Infrared absorbing dye B 0.042g Polyoxyethylene (n = 10) lauryl ether 0.017g Magnesium acetate 0.003g 24 g of water

[0086]

[Chemical 6]

[0087]

The heat-sensitive lithographic printing plate precursor of the present invention has an overcoat layer having a dry weight of 0.05 to 0.20 g.
When it is / m ² , the sensitivity and printing durability are excellent and the scratch resistance is improved.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AA12 AB03 AC08 AD01 BH03                       CC11 DA03 FA10 FA21                 2H096 AA06 BA20 EA04 EA23 GA43                       GA45                 2H114 AA04 AA22 AA23 AA24 AA27                       AA30 BA02 BA10 DA08 DA41                       DA75 EA01 EA03 EA05 EA08                       FA00 GA01 GA34

Claims (3)

[Claims] 1. An ink receiving layer (1) on a support,
(2) Containing 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 metal. It has a hydrophilic layer and (3) a hydrophilic overcoat layer having a dry weight of 0.05 to 0.20 g / m ² , and at least one of the ink receiving layer, the hydrophilic layer and the hydrophilic overcoat layer is photothermal. A heat-sensitive lithographic printing plate precursor containing a converting agent. 2. The dry weight of the hydrophilic layer is 0.40 g /
The heat-sensitive lithographic printing plate precursor according to claim 1, which is at least m ² . 3. The heat-sensitive lithographic printing plate precursor according to claim 1, wherein the hydrophilic overcoat layer contains a resin obtained by partially crosslinking a water-soluble resin.