JP2003118247A - Heat sensitive lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sensitive lithographic printing original plate, with which printing can be performed by being directly installed on a printing machine without being processed after being exposed to light, which is excellent in plate wearability and in which printing scumming hardly develops. SOLUTION: This original plate is formed by providing (1) an ink accepting layer, (2) a hydrophilic layer made of 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 transition metals and (3) a water-soluble over-coating layer on a support under the condition that all the layers such as the ink accepting layer, the hydrophilic layer and the water-soluble over-coating layer include a photothermally converting agent occupying 1 to 50 wt.% of all the solids.

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 precursor which does not require development and has excellent printing durability and stain resistance. More specifically, it is possible to record an image by infrared or near-infrared laser beam scanning exposure based on a digital signal, and the image-recorded product is mounted on a printing machine as it is and printed without going through a conventional developing process. The present invention relates to a lithographic printing plate precursor that can be used.

[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, a hydrophilic layer is provided on a lipophilic substrate or a substrate having an lipophilic layer, and the hydrophilic layer is ablated and removed.

[0004] WO94 / 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. 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 strength of the hydrophilic layer. Although this technology improves printing durability, polyvinyl alcohol, which has a hydrocarbon group and is not necessarily highly hydrophilic, occupies 48% by weight of the hydrophilic layer, so stain resistance is still insufficient and further improvement is required. is there.

WO98 / 40212, WO99 /
In JP 19143 and WO 99/19144, a hydrophilic layer containing a colloid such as silica crosslinked with a crosslinking agent such as aminopropyltriethoxysilane as a main component 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 increases the resistance to printing stains by reducing hydrocarbon groups as much as possible, and improves the printing durability by cross-linking the colloid with a cross-linking agent, but the printing durability is still insufficient at several thousand sheets. Is.

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 can achieve both at the same time. Has not been developed.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems. That is, it is an object of the present invention to provide a heat-sensitive lithographic printing plate precursor that can be directly mounted on a printing machine for printing without performing any processing, has excellent printing durability, and is less likely to cause printing stains.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that a solid-state photothermal conversion agent is added to all layers of an ink receiving layer, a hydrophilic layer and a water-soluble overcoat layer of a heat-sensitive lithographic printing plate precursor. It has been found that the above object can be achieved by containing the colloidal particulate oxide or hydroxide of an element such as silicon in the hydrophilic layer in an amount of 1 to 50% by weight. 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 water-soluble overcoat layer, and all layers of the ink receiving layer, the hydrophilic layer and the water-soluble overcoat layer contain the photothermal conversion agent in a total solid content of 1%.
A heat-sensitive lithographic printing plate precursor which is contained in an amount of ˜50% by weight.

[2] The heat-sensitive lithographic printing plate precursor as described in [1] above, wherein the hydrophilic layer further contains a hydrophilic resin.

In order to increase the exposure sensitivity of the heat sensitive lithographic printing plate precursor, the interface adhesion between the ink receiving layer and the hydrophilic layer is reduced, the hydrophilic layer and the overcoat layer are destroyed, and the heat generated by the exposure is applied. It is important to make effective use of aluminum without diffusing it into the aluminum substrate. It is effective to cause an ablation reaction on the surface of the ink receiving layer to reduce the interfacial adhesion, and to destroy the hydrophilic layer and the overcoat layer, a photothermal conversion agent is contained in the two layers to generate heat in the layer. Is effective. Further, in order to prevent the heat from diffusing into the aluminum substrate, a photothermal conversion agent is added to the upper layer to form an exothermic layer rather than a photothermal conversion agent being localized in the ink receiving layer to form a heat generating layer. It is preferably used as a heat insulating layer. From the above, the distribution of the photothermal conversion agent in three layers leads to an improvement in sensitivity. Furthermore, by distributing the photothermal conversion agent in each layer, the amount of the photothermal conversion agent distributed per layer can be reduced, and the ratio of low molecular components is decreased, so that the film strength of the ink receiving layer is improved and the resistance is improved. Printability is improved. Alternatively, the hydrophilicity of the hydrophilic layer is improved, and it is effective in preventing stains. The heat-sensitive lithographic printing plate precursor of the present invention is effective in increasing the sensitivity because the amount of heat generated is increased by distributing the photothermal conversion agent in all three layers as described above. Further, the dye concentration is increased without impairing the performance of the light-sensitive material (staining property and printing durability), the difference in concentration between the exposed portion and the unexposed portion becomes large, and the plate inspection property is excellent. In addition, since each layer is colored, it is possible to easily check visually the defects in the manufacturing process, and it is possible to facilitate product inspection.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The heat-sensitive lithographic printing plate precursor of the present invention is characterized in that all of the ink receiving layer, the hydrophilic layer and the water-soluble overcoat layer each contain a photothermal conversion agent in the range of 1 to 50% by weight of the total solid content. To do. More preferably 5 to 3
It is contained in the range of 0% by weight. As for the layer distribution ratio of the ink-receiving layer, the hydrophilic layer and the water-soluble overcoat layer of the light-heat converting agent, at least 5% by weight of the total light-heat converting agent is distributed so that each layer contains at least 5% by weight. The addition ratio to each layer can be arbitrarily selected. Further, it is preferably added to the ink receiving layer in a proportion of 10 to 90% by weight, the hydrophilic layer in a proportion of 5 to 50% by weight, and the overcoat layer in a proportion of 5 to 50% by weight.

The hydrophilic layer used in the heat-sensitive lithographic printing plate precursor of the present invention is selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metals. A layer which contains a colloid of an oxide or hydroxide of at least one element, a hydrophilic resin, and a photothermal conversion agent and is insoluble in fountain solution in lithographic printing using fountain solution. These colloids are produced by various methods such as hydrolysis of halides and alkoxy compounds of the above elements and condensation of hydroxides, and the above elements form a network structure through oxygen atoms and at the same time unbound hydroxyl groups and It has an alkoxy group and has a structure in which these are mixed. From the initial hydrolysis and condensation stage with many active alkoxy groups and hydroxyl groups,
As the reaction proceeds, the particle size increases and becomes inactive. Colloidal particles are typically 2 nm to 500 nm
In the case of silica, spherical particles having a diameter of 5 nm to 100 nm are preferable in the present invention. It is also possible to use a pearl neck-shaped colloid in which spherical particles of 10 nm to 50 nm are connected in a length of 50 nm to 400 nm. Furthermore, feather-like particles of 100 nm × 10 nm such as aluminum colloid are also effective.

The hydrophilic resin used in the hydrophilic layer of the present invention is preferably one having a hydrophilic group such as hydroxy, carboxy, hydroxyethyl, hydroxypropyl, amino, aminoethyl, aminopropyl and carboxymethyl. 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 acid. And salts thereof, 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, hydroxy Butyl methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene glycol Lumpur, polypropylene glycol, polyvinyl alcohol, degree of hydrolysis of at least 60 wt%, preferably at least 80 wt% of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone,
Examples thereof include acrylamide homopolymers and copolymers, methacrylamide homopolymers and polymers, and N-methylolacrylamide homopolymers and copolymers.

A particularly preferred hydrophilic resin is a hydroxy group-containing polymer, specifically, a homopolymer or a copolymer of hydroxyethyl acrylate or hydroxyethyl methacrylate.

The addition ratio of these hydrophilic resins is preferably 0.1 to 30% by weight, more preferably 5 to 20% by weight based on the total solid content of the hydrophilic layer. If it is less than this range, the printing durability is not sufficient, and if it is more than this range, printing stains tend to occur.

The photothermal conversion agent added to all layers of the ink-philic ink-receptive layer, the hydrophilic layer and the water-soluble overcoat layer of the heat-sensitive lithographic printing plate precursor of the present invention is a light-to-heat converter for increasing the heat-sensitive sensitivity, and a light having a wavelength of 700 nm or more is used. Any substance that absorbs
Various pigments and dyes can be used. As a pigment,
Commercial Pigment and Color Index (CI) Handbook, "Latest Pigment Handbook" (edited by Japan Pigment Technology Association, 1977)
Annual, "Latest pigment application technology" (CMC Publishing, 1986)
The pigments described in "Printing Ink Technology" (CMC Publishing, 1984) can be used.

The types of pigments include black pigments, brown pigments, red pigments, violet pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and 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. As the method of surface treatment, a method of surface coating a hydrophilic resin or a lipophilic resin, a method of attaching a surfactant, or a reactive substance (for example, silica sol, alumina sol, silane coupling agent, epoxy compound, isocyanate compound, etc.) A method of binding to the pigment surface can be considered. The above surface treatment method is "property and application of metallic soap" (Koshobo), "printing ink technology"
(CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).
Among these pigments, those that absorb infrared rays or near infrared rays are particularly preferable because they are suitable for use in lasers that emit infrared rays or near infrared rays.

As such a pigment which absorbs infrared rays or near infrared rays, carbon black, carbon black coated with a hydrophilic resin or carbon black modified with silica sol is preferably used. Among these, carbon black whose surface is coated with a hydrophilic resin or silica sol is useful as a resin that is particularly easily dispersed with a water-soluble resin and does not impair hydrophilicity.

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 the dye, commercially available dyes and known dyes described in the literature (for example, "Dye Handbook" edited by the Society of Synthetic Organic Chemistry, published in 1945) can be used. Specific examples include dyes such as azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. Among these dyes, those that absorb infrared rays or near infrared rays are particularly preferable because they are suitable for use in lasers that emit infrared rays or near infrared rays.

Examples of dyes that absorb infrared rays or near infrared rays include JP-A-58-125246 and JP-A-59-8.
4356, cyanine dyes described in JP-A-60-78787 and the like, methine dyes described in JP-A-58-173696, JP-A-58-181690 and JP-A-58-194595. JP-A-58-1127
93, JP-A-58-224793, and JP-A-59-4.
8187, JP-A-59-73996, JP-A-60-
No. 52940, naphthoquinone dyes described in JP-A-60-63744, etc., squarylium dyes described in JP-A-58-112792, UK Patent 43
Cyanine dyes described in US Pat. No. 4,875 and US Pat. No. 4,75
6,993 dyes, U.S. Pat. No. 4,973,57
The cyanine dyes described in No. 2 and the dyes described in JP-A No. 10-268512 can be mentioned.

Also, as a dye, US Pat. No. 5,156,6
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.
No. 42645 (US Pat. No. 4,327,169), a trimethine thiapyrylium salt, JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363.
No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and the pyrylium compounds described in JP-A-59-2161.
46, cyanine dyes, US Pat. No. 4,283,4
No. 75 pentamethine thiopyrylium salt, etc., and the pyrylium compounds disclosed in Japanese Examined Patent Publication Nos. 5-13514 and 5-19702, Epolig manufactured by Eporin.
htIII-178, EpolightIII-130, Ep
Light III-125 and the like are also preferably used. Among these dyes, particularly preferred specific examples are listed below by structural formulas.

[0024]

[Chemical 1]

[0025]

[Chemical 2]

[0026]

[Chemical 3]

[0027]

[Chemical 4]

[0028]

[Chemical 5]

[0029]

[Chemical 6]

The proportion of the photothermal conversion agent added to the hydrophilic layer of the present invention is 1 to 50% by weight, preferably 5 to 30% by weight, based on the total solid content of the hydrophilic layer. If the amount of the photothermal conversion agent added is less than 1% by weight, the sensitivity will be low, and if it exceeds 50% by weight, the hydrophilicity of the layer will be impaired and the durability of the layer will be reduced.

In the hydrophilic layer of the present invention, in addition to the above colloid, hydrophilic resin and photothermal conversion agent, a cross-linking agent that promotes cross-linking of the colloid may be added. As a crosslinking agent for such colloid, an initial hydrolysis-condensation product of tetraalkoxysilane, trialkoxysilylpropyl-N, N, N-trialkylammonium halide or aminopropyltrialkoxysilane is preferable. The addition ratio is preferably 5% by weight or less of the total solid content of the hydrophilic layer.

Further, a crosslinking agent for a hydrophilic resin may be added to the hydrophilic layer of the present invention for the purpose of increasing printing durability during printing. Examples of the cross-linking agent for such hydrophilic resin include formaldehyde, glyoxal, polyisocyanate, initial hydrolysis / condensation product of tetraalkoxysilane, dimethylol urea and hexamethylol melamine.

Further, the hydrophilic layer of the present invention contains a well-known fluorinated surfactant in order to improve the surface condition of coating.
Silicon type surfactants, polyoxyethylene type surfactants, etc. may be added.

The coating thickness of the hydrophilic layer of the present invention is preferably 0.1 μm to 3 μm. More preferably, 0.
It is from 5 μm to 2 μm. If it is too thin, the durability of the hydrophilic layer is poor and the printing durability during printing is poor. If it is too thick, a large amount of energy is required to ablate the hydrophilic layer from the ink receiving layer underneath, and a long drawing time is required when exposing with a laser, which results in production of a printing plate. Sex decreases. When writing is performed using a general commercially available semiconductor laser, the thickness is about 300 to 4 with a thickness of about 0.5 μm.
The energy of 00mJ / cm ^2, requiring energy 400~500mJ / cm ² at a thickness of about 1.5 [mu] m.

As the substrate having an ink-receptive surface or coated with an ink-receptive layer used in the present invention, a dimensionally stable plate is used. Paper, lipophilic plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper, nickel, stainless steel plate, etc.), plastic film (eg, cellulose diacetate, trisodium) Cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film laminated or vapor-deposited with the above metals are included. .

Preferred substrates are polyethylene terephthalate film, polycarbonate film, aluminum or steel plate, or aluminum or steel plate laminated with a lipophilic plastic film.

As the aluminum plate used in the present invention, an aluminum plate made of a publicly known and publicly known material can be appropriately used.

It is preferable to roughen the surface of the aluminum plate before using it. When applied to an ink receiving layer made of an organic polymer by roughening, the adhesiveness to the substrate can be easily secured. For the roughening, a well-known and publicly-used aluminum plate surface treatment technique can be used, and the center line surface roughness (Ha) of the aluminum plate surface is 0.3 to 1.0 μm.
It is preferable that it is applied in the range of.

The organic polymer coated as an ink receiving layer on the surface of the substrate of the present invention is one that is soluble in a solvent and can form a lipophilic film. Further, it is desirable that it is insoluble in the coating solvent of the hydrophilic layer as the upper layer, but in some cases, it is desirable that one that partially swells in the coating solvent of the upper layer has excellent adhesiveness with the upper layer. In addition, when an organic polymer that is soluble in the coating solvent for the upper layer is used, it is desirable to cure it by adding a crosslinking agent in advance.

Examples of 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 copolymers thereof. , Polyvinylphenol, polyvinyl halogenated phenol, methacrylic resin and its copolymer, acrylamide copolymer, methacrylamide copolymer, polyvinyl formal, polyamide, polyvinyl butyral, polystyrene, cellulose ester resin, polyvinyl chloride and polyvinylidene chloride Etc. can be mentioned. Among these, as a more preferable compound, a resin having a hydroxy group, a carboxy group, a sulfonamide group or a trialkoxysilyl group in a side chain is excellent in adhesiveness with a substrate or an upper hydrophilic layer, and depending on the case, a crosslinking agent may be used. It is desirable because it cures easily. In addition, acrylonitrile copolymer, polyurethane, a copolymer having a sulfonamide group in a side chain or a copolymer having a hydroxy group in a side chain, which is photocured with a diazo resin, is preferable.

Others: phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol-modified xylene, tert-butylphenol, Novolac resin and resol resin of condensation with formaldehyde such as octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl, p-Cl), bromophenol (m-Br, p-Br), salicylic acid, phloroglucinol and the like, Further, a condensation resin of the above phenol compound and acetone is useful.

Other suitable 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 having an aromatic hydroxy group,
Methacrylamides, acrylic esters, methacrylic esters 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) acrylic acid esters and methacrylic acid esters 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 (Substituted) acrylic acid esters such as benzyl acrylate, 2-chloroethyl acrylate, 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, methacrylic acid-
(Substituted) methacrylic acid esters such as 2-chloroethyl, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, (5) acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N- Ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-cyclohexylmethacrylamide, N-hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N- Phenylmethacrylamide, N-benzylacrylamide, N
-Benzyl methacrylamide, N-nitrophenyl acrylamide, N-nitrophenyl methacrylamide, N
Acrylamide or methacrylamide such as -ethyl-N-phenylacrylamide and N-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.

An ink receiving layer can be provided on the substrate by dissolving these organic polymers in a suitable solvent and coating and drying them on the substrate. Although the organic polymer alone can be dissolved in a solvent and used, a crosslinking agent, an adhesion aid, a coloring agent, inorganic or organic fine particles, a coating surface condition improving agent, and a plasticizer can be added as necessary. In addition, a photothermal conversion agent for increasing the sensitivity and a heat coloring system or a decoloring system for forming a printout image after exposure may be added to the ink receiving layer.

Specific cross-linking agents for cross-linking organic polymers include diazo resins, aromatic azide compounds, epoxy resins, isocyanate compounds, blocked isocyanate compounds, initial hydrolyzed condensates of tetraalkoxy silicon, glyoxal, aldehyde compounds and methylol. A compound can be mentioned.

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, quinizarin,
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, Japanese Patent Application No. 7-335
The dyes described in Japanese Patent No. 145 can be mentioned. When the dye is added to the ink receiving layer, it is usually about 0.02 to 10% by weight based on the total solid content of the receiving layer,
More preferably, it is about 0.1 to 5% by weight.

Further, a fluorine-based surfactant or a silicon-based surfactant which is a well-known compound as a coating surface condition improving agent can also 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 powder 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 hydrophobicity. Examples thereof include converted silica particles, alumina particles, titanium dioxide particles, other heavy metal particles, clay and talc. The addition of these inorganic or organic fine powders to the ink receiving layer has the effect of improving the adhesiveness with the hydrophilic layer above and increasing the printing durability in printing. The proportion of these fine powders added to the ink receiving layer is 80% by weight or less, preferably 40% by weight 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 compound of a coloring system or a decoloring system in order to make the image area and the non-image area clear when exposed. For example, leuco dyes (leucomalachite green, leuco crystal violet, lactones of crystal violet, etc.) and PH discoloring dyes (eg ethyl violet, Victoria Poor Blue BOH, etc.) along with thermal acid generators such as diazo compounds and diphenyliodonium salts. Dye) 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 color forming systems is 10% by weight or less, preferably 5% by weight or less, based on the total amount in the ink receiving layer.

Further, a light-heat converting agent is added to the ink receiving layer of the present invention in order to enhance heat sensitivity. The light-heat converting agent may be the above infrared absorbing dye or pigment, but in this case, a lipophilic dye or pigment is preferable. Particularly preferred are the lipophilic ones of carbon black and cyanine dyes. Specific compounds of the lipophilic cyanine dye are listed below.

[0055]

[Chemical 7]

The proportion of the photothermal conversion agent added to the ink receiving layer is 1 to 50% by weight of the total solid content of the ink receiving layer,
It is preferably in the range of 5 to 30% by weight. If the addition amount of the photothermal conversion agent is less than 1% by weight, the sensitivity becomes low,
If it exceeds, the durability of the layer will decrease.

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 etc.), amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone etc.), gamma-butyrolactone, methyl lactate, ethyl lactate etc. can be used. it can. These solvents are used alone or in a mixed state. When preparing a coating liquid, the concentration of the ink receiving layer constituent components (total solid content including additives) in the solvent is preferably 1 to 50% by weight. 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 weight to 50% by weight.

The thickness of the ink receiving layer of the present invention after coating and drying is not particularly limited, but may be 0.1 μm or more. When it is provided on a metal plate, it also has a role as a heat insulating layer, so that the thickness is preferably 0.5 μm or more. If the ink receiving layer is too thin, the heat generated will be dissipated to the metal plate and the sensitivity will decrease. In addition, in the case of a hydrophilic metal plate, abrasion resistance is required for the ink receiving layer, so that printing durability cannot be ensured. 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 μm.

The heat-sensitive lithographic printing plate precursor of the present invention is an overcoat comprising a water-soluble resin and a photothermal conversion agent on the hydrophilic layer in order to suppress scattering of dust due to ablation and to prevent the hydrophilic layer from being contaminated by lipophilic substances. Layers can be provided.

The water-soluble overcoat layer used in the present invention can be easily removed during printing and contains a resin selected from water-soluble organic or inorganic polymer compounds and a photothermal conversion agent. As the water-soluble organic or inorganic polymer compound used here, a film formed by coating and drying has film-forming ability, specifically, polyvinyl acetate (however, a hydrolysis rate of 65% or more) , Polyacrylic acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal Salts or amine salts, polyacrylamide and copolymers thereof, polyhydroxyethyl acrylate, polyvinylpyrrolidone and copolymers thereof, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl -1-Propanesulfonic acid and its alkali metal salts Amine salt,
Poly-2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic, fibrin derivative (for example, carboxymethyl cellulose, carboxyethyl cellulose,
Methyl cellulose etc.) and its modified products, white dextrin, pullulan, enzymatically-decomposed etherified dextrin and the like. In addition, two or more kinds of these resins may be mixed and used depending on the purpose.

In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of coating with an aqueous solution for the purpose of ensuring uniformity of coating. 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 weight, more preferably 1 to 3% by weight.

The proportion of the photothermal conversion agent added to the overcoat layer of the present invention is 1 to 50 of the total solid content of the overcoat layer.
% By weight, preferably in the range of 5 to 30% by weight. If the amount of the photothermal conversion agent added is less than 1% by weight, the sensitivity will be low, and if it exceeds 50% by weight, the hydrophilicity of the layer will be impaired and the durability of the layer will be reduced. The photothermal conversion agent that can be added to the overcoat layer may be the infrared absorbing dye or pigment described above, but a water-soluble cyanine dye suitable for addition to the hydrophilic layer is preferable.

The thickness of the overcoat layer used in the present invention is preferably 0.05 μm to 4.0 μm, and more preferably 0.1 μm to 1.0 μm. Too thick,
It takes time to remove the overcoat layer during printing,
In addition, a large amount of the water-soluble resin that has melted out affects dampening water, which causes adverse effects such as the occurrence of roller strips during printing, and the fact that the ink does not adhere to the image area. If it is too thin, the film formability may be impaired.

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 or the like, scanning exposure with an infrared laser, high-illuminance flash exposure with a xenon discharge lamp or infrared lamp exposure is 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. When printing is started using ink and dampening water, the overcoat layer is removed by the dampening water and at the same time the hydrophilic layer in the exposed area is also removed, and the ink is inked in the ink receiving layer below it, and printing starts. To be done. Also,
The lithographic printing plate precursor of the present invention can be mounted on a cylinder of a printing machine, then exposed by a laser mounted on the printing machine, and then subjected to on-machine development with dampening water and / or ink. .

[0065]

Example 1

[Production of aluminum substrate] Aluminum 99.5 weight
%, Copper 0.01% by weight, titanium 0.03% by weight,
JI containing 0.3% by weight of iron and 0.1% by weight of silicon
SA1050 aluminum material 0.24 mm thick rolled plate
20 of 400 mesh pumice stone (manufactured by Kyoritsu Kiln)
Using a weight percent aqueous suspension and a rotating nylon brush
After graining the surface, it was thoroughly washed with water. This 15
Weight% sodium hydroxide aqueous solution (aluminum 4.5 weight)
The amount of aluminum dissolved is 5g / m²
After being etched so as to become, the film was washed with running water. Change
Neutralized with 1% by weight nitric acid aqueous solution, and then 0.7% by weight nitric acid.
Anode in acid aqueous solution (containing 0.5% by weight of aluminum)
Square wave alternating wave with 10.5V hour voltage and 9.3V cathode voltage
Shaped voltage (current ratio r = 0.90, Japanese Patent Publication No. 58-5796)
160) using the current waveform described in the examples of the publication)
C / dm²Electrolytic surface roughening treatment was performed with the amount of electricity at the time of the anode.
After washing with water, in a 10% by weight aqueous sodium hydroxide solution at 35 ° C
Soaked in aluminum, the amount of aluminum dissolved is 1g / m ²Will be
After etching as described above, it was washed with water. Next, 50 ℃, 30
Immerse in a wt% sulfuric acid aqueous solution, desmut, and then water
Washed Furthermore, a 20% by weight aqueous solution of sulfuric acid at 35 ° C.
(Containing 0.8% by weight of minium)
A porous anodic oxide film forming treatment was performed. That is, the current density
13A / dm²Electrolysis and adjust the electrolysis time.
, Anodized film weight 2.7g / m²The support of
It was The support obtained as described above is a Macbeth RD.
The reflection density measured with a 920 reflection densitometer is 0.30,
The core wire average roughness Ra was 0.52 μm.

[Coating of ink receiving layer] On the above support,
The ink receiving layer coating solution having the following composition is applied in an amount of 11.2
It was applied with a bar coater so as to have a volume of 5 ml / m ² . Then, it is heated and dried at 100 ° C. for 1 minute, and the dry coating amount is about 0.
An ink receiving layer of 40 g / m ² was obtained.

[0067] (Ink receiving layer coating liquid)     Epicoat 1009 (produced by Yuka Shell Epoxy Co., Ltd.) 8.0 g     Epicoat 1001 (produced by Yuka Shell Epoxy Co., Ltd.) 2.8 g     Light-to-heat conversion agent (IR-40 described herein) 1.2 g     Methyl ethyl ketone 80g     170 g of propylene glycol monomethyl ether

[Coating of Hydrophilic Layer] On the ink receiving layer thus formed, the following hydrophilic layer coating liquid (I) is bar-coated, dried at 100 ° C. for 1 minute, and the dry coating amount is 0.1. 45
A hydrophilic layer of g / m ² was obtained.

[0069] (Hydrophilic layer coating liquid (I))     Methanol silica (manufactured by Nissan Chemical Industries, Ltd .: silica particle size 10 to 20 nm,       Colloid consisting of 30% by weight methanol solution) 30 g     Polyacrylic acid (weight average molecular weight 250,000)       Methanol solution containing 5% by weight 20 g     Light-to-heat conversion agent (IR-31 described herein) 1.3 g     Methyl lactate 1g     Methanol 17.53g

A coating solution for coating an overcoat layer having the following composition was applied onto the hydrophilic layer by a bar and dried at 100 ° C. for 90 seconds to obtain a heat-sensitive lithographic printing plate having an overcoat layer having a dry coating weight of 0.15 g / m ^2. A master plate was prepared.

[0071] (Overcoat layer coating liquid)     15 g of aqueous solution containing 28% by weight of gum arabic     Photothermal conversion agent (dye IR-31 described herein) 0.42 g     Polyoxyethylene nonyl phenyl ether       (Aqueous solution containing 10% by weight) 1.68 g     Ion-exchanged water 220g

The above heat-sensitive lithographic printing plate precursor was used for 180 m by a Trendsetter (plate setter equipped with 40 W 830 nm semiconductor laser) manufactured by Creo.
It was exposed with an energy of J / cm ² . The exposed original plate was directly attached to the Heidelberg printer SOR-M without further treatment, and the plate etchant IF-1 was used.
02 (manufactured by Fuji Photo Film Co., Ltd.) / Water (volume ratio 4/1
00) dampening water and Dainippon Ink and Chemicals, Inc.
When using Geos G ink ink manufactured by Doshiseki ink, the fountain solution and the ink were operated at the same time, and the art-coated paper was supplied to start printing, the ink was completely inked on the fifth printed sheet, and then 2
A good print without stains was obtained.

[Examples 2 to 4, Comparative Examples 1 to 4] Example 1
A heat-sensitive lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the coating amount of the photothermal conversion agent in each layer was set to the distribution shown in Table 1. Next, when these heat-sensitive lithographic printing plate precursors were exposed and printed in the same manner as in Example 1, all of the printing plate precursors of the present invention had imprinting within 5 sheets. In addition, from each printing plate, 20,000 good prints without stains were obtained.

[0074]

[Table 1]

As is clear from the above results, the heat-sensitive lithographic printing plate precursors of the respective examples according to the present invention were mounted on a printing machine immediately after each exposure, and the ink was completely infiltrated at the beginning of printing. Although satisfactory results were obtained with no stain and good printing durability, the heat-sensitive lithographic printing plate precursors of each comparative example were unsatisfactory in some results.

[0076]

As described above, in the heat-sensitive lithographic printing plate precursor of the present invention, the light-to-heat converting agent is contained in each of the ink receiving layer, the hydrophilic layer and the water-soluble overcoat layer in a total solid content of 1%.
The amount of heat generation is increased by containing the colloidal particulate oxide or hydroxide of an element such as silicon in the hydrophilic layer in an amount of 50 to 50% by weight. It is effective for the ablation reaction between the hydrophilic layer and the water-soluble overcoat layer without impairing the performance (dirt resistance, printing durability), and also improves the film strength of the ink-receiving layer and improves the printing durability. Play. According to the invention, after exposure,
It is possible to mount it on a printing machine as it is without performing processing and perform printing, and it is possible to obtain a heat-sensitive lithographic printing plate precursor having excellent printing durability and less likely to cause printing stains.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H025 AA12 AA13 AB03 AC08 AD03                       BH01 CB52 CC11 DA36 DA40                       FA10                 2H096 AA06 BA09 EA04                 2H114 AA04 AA22 AA23 BA02 BA10                       DA04 DA08 DA41 DA64 EA01                       EA03 EA04 EA08 GA01

Claims (2)

[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 water-soluble overcoat layer, and all layers of the ink receiving layer, the hydrophilic layer and the water-soluble overcoat layer contain the photothermal conversion agent in a total solid content of 1%.
A heat-sensitive lithographic printing plate precursor which is contained in an amount of ˜50% by weight. 2. The heat-sensitive lithographic printing plate precursor according to claim 1, wherein the hydrophilic layer further contains a hydrophilic resin.