JPH0862830A - Photosensitive planographic printing plate and its production - Google Patents

Abstract

PURPOSE: To provide a photosensitive planographic printing plate high in quality of dot picture and excellent in safelight property by increasing gradient (making high contrast) without deteriorating sensitivity. CONSTITUTION: The photosensitive planographic printing plate is provided with a photosensitive layer containing a polymerizable composition having an addition-polymerizable unsaturated bound, a photopolymerization initiator and an alkali-soluble polymer compound on a supporting body having a hydrophilic surface and is provided with a met layer, in which a compound reacting by exposure to change the absorption spectrum in the region from ultraviolet to visible light and free from the change of the solubility to a developer by the exposure is incorporated, on the surface of the photosensitive layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive lithographic printing plate and a method for producing the same.

[0002]

2. Description of the Related Art A composition in which a photopolymerization initiator is mixed with a polymerizable compound having an addition-polymerizable unsaturated group is photopolymerized by irradiation with actinic rays such as ultraviolet rays to become a polymer. It is used as a light-sensitive material for forming an image by utilizing changes in physical properties such as solubility and adhesiveness associated with the change to the polymer.

These photosensitive materials are used in photolithography. Since these photosensitive materials give images with long gradation and soft tone, when they are used as photoengraving materials, not only do dot gains occur in the halftone dot images, the quality of the halftone dot images on the printed matter deteriorates, but also indoors in the workplace. It has a drawback that it is easily exposed to light and the like (poor safelight property), and stains (so-called fog) occur in non-image areas.

Therefore, in these photosensitive materials, it has been a major technical problem to shorten the gradation so as to obtain a high contrast image and prevent these defects.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photosensitive lithographic printing plate which has a short gradation (hardening) without decreasing the sensitivity, has a high halftone dot image quality and a good safelight property. To do.

[0006]

The above-mentioned objects of the present invention are: (1) A polymerizable compound having an addition-polymerizable unsaturated bond, a photopolymerization initiator, and a high alkali-solubility on a support having a hydrophilic surface. Having a photosensitive layer containing a molecular compound, and in a photosensitive lithographic printing plate having a matte layer on the surface of the photosensitive layer, the matte layer reacts by exposure, the absorption spectrum in the ultraviolet to visible light region changes, and A photosensitive lithographic printing plate comprising a compound whose solubility in a developing solution does not change upon exposure. (2) A compound that reacts upon exposure, changes its absorption spectrum in the ultraviolet to visible light region, and its solubility in a developer does not change upon exposure, and its absorption maximum wavelength is centered on the light absorption maximum wavelength of the photopolymerization initiator. There is a range of 60nm before and after,
Further, the photosensitive lithographic printing plate as described in (1) above, which is a compound whose absorbance is reduced by exposure. (3) 1,2-naphthoquinone- (2) is a compound which reacts upon exposure to light, changes its absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developing solution does not change upon exposure.
-Diazide-5-sulfonic acid or 1,2-naphthoquinone- (2) -diazide-4-sulfonic acid or a metal salt, ammonium salt or acid chloride thereof, or (1) or (2) above. ) The photosensitive lithographic printing plate described above. (4) 1,2-naphthoquinone- (2) is a compound which reacts upon exposure, changes its absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developer does not change upon exposure.
-Diazide-5-sulfonic acid or 1,2-naphthoquinone- (2) -diazide-4-sulfonic acid and a sulfonic acid ester of a compound having a phenolic hydroxyl group, (1) or (2) ) The photosensitive lithographic printing plate described above. (5) A matting agent dispersion liquid containing a water-soluble polymer compound and a compound in which the matte layer reacts upon exposure to change the absorption spectrum in the ultraviolet to visible light region, and the solubility in a developing solution does not change upon exposure The photosensitive lithographic printing plate as described in (1) to (4) above, which is formed from (6) A photosensitive layer containing a polymerizable compound having an addition polymerizable unsaturated bond, a photopolymerization initiator, and an alkali-soluble polymer compound is provided on a support having a hydrophilic surface, and the photosensitive layer surface is exposed to light. The matte layer is prepared by spray-coating a matting agent dispersion containing a compound and a water-soluble polymer compound that react with each other, change the absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developing solution does not change upon exposure. The method for producing a photosensitive lithographic printing plate as described in (1) to (5) above, which further comprises: Achieved by

The present invention will be described in detail below.

First, the photosensitive layer containing the polymerizable compound having an addition-polymerizable unsaturated bond, the photopolymerization initiator, and the alkali-soluble polymer compound of the present invention will be described.

Polymerizable compounds having an addition polymerizable unsaturated bond used in the photopolymerizable composition are known, and in the photopolymerizable composition of the present invention, these known addition polymerizable unsaturated bonds are contained. A polymerizable compound can be used and may have any chemical structure, but a compound having two or more addition-polymerizable unsaturated bonds in the molecule is preferable. Two or more polymerizable compounds having an addition-polymerizable unsaturated bond may be used in combination.

Examples of the polymerizable compound having an addition-polymerizable unsaturated group include unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, unsaturated carboxylic acids and aromatic polyhydroxy compounds. And the esters obtained by the esterification reaction of the unsaturated carboxylic acid and polyvalent carboxylic acid and the above-mentioned aliphatic polyhydroxy compound, polyvalent hydroxy compound such as aromatic polyhydroxy compound, and the like. JP-A-59-71048, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate, hydroquinone di (meth) acrylate. ,
Examples include pyrogallol triacrylate and 2,2-bis (4-acryloxydiethoxyphenyl) propane. In addition, (meth) such as ethylenebis (meth) acrylamide and hexamethylenebis (meth) acrylamide
Examples thereof include acrylamides, vinyl urethane compounds and epoxy (meth) acrylates.

The amount of the polymerizable compound having an addition-polymerizable unsaturated group used in the photopolymerizable composition of the present invention is usually 5 to 70% by weight, preferably about 5 to 70% by weight based on the total solid content of the photopolymerizable composition. , 10 to 50% by weight.

The photopolymerization initiator that can be used in the present invention is not particularly limited, and conventionally known ones used for photopolymerizable compositions can be used. Examples thereof include benzoin, benzoin alkyl ether, benzophenone, anthraquinone,
Any of Michler's ketone, trihalomethyl-s-triazine compounds, oxadiazole compounds, biimidazole-Michler's ketone complex system, thioxanthone-aromatic tertiary amine complex system and the like can be preferably used.

As the photopolymerization initiator, a compound having absorption at a wavelength of a light source used for exposing a photosensitive lithographic printing plate is usually used.

The amount of the photopolymerization initiator used is usually 0.5 to 30% by weight, more preferably 2 to 10% by weight, based on the total solid content of the photosensitive layer.

The alkali-soluble polymer compound that can be used in the present invention is not particularly limited, and conventionally known alkali-soluble polymer compounds used in photopolymerizable compositions can be used, and polymers having any chemical structure can be used. Even compounds can be used, and examples thereof include polyamide, polyester, polycarbonate, polystyrene, polyurethane, polyvinyl chloride, and copolymers thereof, polyvinyl butyral resin, polyvinyl formal resin, shellac, epoxy resin, phenol resin, acrylic resin and the like. To be Further, two or more of these alkali-soluble polymer compounds may be used in combination.

The preferred alkali-soluble polymer compound is
(1) Unsaturated carboxylic acids such as methacrylic acid, which are copolymers of vinyl-based monomers,
(2) Unsaturated carboxylic acid esters such as methyl methacrylate, and (3) phenolic hydroxyl group-containing monomers such as hydroxyphenyl methacrylamide and the like.

It is necessary to use, as a constituent monomer of these copolymers, a monomer that makes the polymer compound soluble in alkali.

In the present invention, the term "alkali-soluble" refers not only to those soluble in alkaline water but also those having swellability in alkaline water.

In the present invention, the alkali-soluble polymer compound preferably used is a vinyl monomer having an aromatic hydroxyl group in its side chain, specifically o, m, p-hydroxyphenyl (meth) acrylamide, o. , M, p-
Obtained by copolymerizing hydroxystyrene, o, m, p-hydroxyphenyl (meth) acrylate, o, m, p-hydroxyphenylmaleimide and the like with vinyl monomers shown in (a) to (k) below. Examples thereof include vinyl copolymers having an aromatic hydroxyl group in the side chain. (A) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (b) acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, etc. α, β-unsaturated carboxylic acid,
(C) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid-
(Substituted) alkyl acrylates such as 2-chloroethyl, glycidyl acrylate and N-dimethylaminoethyl acrylate, (d) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate. , (Substituted) alkyl methacrylates such as N-dimethylaminoethyl methacrylate,
(E) Acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N- Acrylamides or methacrylamides such as nitrophenyl acrylamide and N-ethyl-N-phenyl acrylamide, (f) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether and other vinyl ethers. (G) vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate, etc. Glycol ester compounds, (h) styrene,
Styrenes such as α-methylstyrene, methylstyrene and chloromethylstyrene, (i) vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone and phenyl vinyl ketone, (j) ethylene, propylene, isobutylene, butadiene, It is also possible to copolymerize olefins such as isoprene, (k) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, and other monomers copolymerizable with the above monomers.

From the standpoint of developability, the vinyl copolymer preferably contains the unsaturated carboxylic acid mentioned in (b) above, and the preferable acid value is 10 to 10.
It is 0, and the preferred molecular weight is 30,000 to 130,000.

The vinyl copolymer used in the present invention is usually 30 to 99% by weight, preferably 4% by weight, based on the solid content of the photosensitive layer.
It is recommended to contain 0 to 95% by weight.

Various additives other than the above may be added to the photosensitive layer of the present invention.

It is preferable to add a diazo compound to the photosensitive layer of the present invention, since it improves the adhesion to the support and reduces the polymerization inhibition caused by the presence of oxygen.

Examples of the diazo compound that can be used in the present invention include condensation resins of aromatic diazonium compounds and carbonyl compounds and salts of these condensation resins. These condensation resins have COO in their molecule.
Those into which a substituent imparting alkali solubility such as H and SO ₃ H is introduced are preferable.

The above diazo compound is added to the photopolymerizable composition in an amount of 1
It is preferable that the content is up to 20% by weight.

The photosensitive layer of the present invention may further contain a dye. The dye is used for the purpose of obtaining a visible image by exposure (exposed visible image) and a visible image after development.

As the dye, those which change color tone by reacting with free radicals or acids can be preferably used.
Here, "the color tone changes" includes both a change from colorless to a color tone, and a change from a colored to a colorless or different color tone. Preferred dyes are those which form a salt with an acid to change the color tone.

Examples of dyes that change from colored to colorless or to different colored tones include Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) and Oil Blue # 6.
03 [manufactured by Orient Chemical Industry Co., Ltd.], patent pure blue [manufactured by Sumitomo Sangoku Chemical Co., Ltd.], crystal violet, brilliant green, ethyl violet, methyl violet, methyl green, erythrosin B, basic fuchsin, malachite green, oil red, m-
Cresol purple, rhodamine B, auramine, 4-
triphenylmethane type, diphenylmethane type represented by p-diethylaminophenyliminonaphthoquinone, cyano-p-diethylaminophenylacetanilide and the like,
Oxazine, xanthene, iminonaphthoquinone,
Examples include azomethine-based or anthraquinone-based dyes.

On the other hand, examples of dyes that change from colorless to colored include, for example, leuco dyes and triphenylamine, diphenylamine, o-chloroaniline,
1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis-dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p ', p "-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p ', p "-triamino-o-
Methyltriphenylmethane, p, p′-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane, p,
Examples thereof include primary or secondary arylamine dyes represented by p ′, p ″ -triaminotriphenylmethane.

Of these dyes, triphenylmethane type and diphenylmethane type dyes are preferable, triphenylmethane type dyes are more preferable, and Victoria Pure Blue BOH is particularly preferable.

The above dye is usually contained in the total solid content of the photosensitive layer in an amount of 0.5 to 10% by weight, preferably about 1 to 5% by weight.

Various additives can be further added to the photosensitive layer of the present invention.

For example, alkyl ethers (eg, ethyl cellulose, methyl cellulose) for improving coating properties, fluorochemical surfactants and nonionic surfactants (eg, Pluronic L-64 (Asahi Denka Co., Ltd.)
A), a plasticizer for imparting flexibility and abrasion resistance to the coating film (for example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate,
Tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid oligomers and polymers), an oil sensitizer for improving the oil sensitivity of the image area (for example, JP-A-55) -527-styrene-maleic anhydride copolymer alcohol-based half-esterified products), stabilizers [eg phosphoric acid, phosphorous acid, organic acids (citric acid, oxalic acid, benzenesulfonic acid, naphthalenesulfone) Acid, 4-methoxy-2-hydroxybenzophenone-5-sulfonic acid, tartaric acid, etc.), a development accelerator (eg, higher alcohol, acid anhydride, etc.) and the like.
The amount of these additives to be added varies depending on the intended purpose, but generally 0.01 to 0.01% based on the total solid content of the photosensitive layer.
It is 30% by weight.

The photosensitive lithographic printing plate of the present invention comprises a polymerizable compound having an addition-polymerizable unsaturated group, a photopolymerization initiator, an alkali-soluble polymer compound, and predetermined amounts of various additives to be added if necessary. A photopolymerizable composition comprising a suitable solvent (methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, acetone, methyl ethyl ketone,
By dissolving in methanol, dimethylformamide, dimethylsulfoxide, water or a mixture thereof) to prepare a coating solution of the photopolymerizable composition, coating it on a support and drying it to form a photosensitive layer. Obtainable.

The concentration of the photopolymerizable composition in the coating liquid is 1
It is desirable to be in the range of 50 wt%.

For coating, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and curtain coating can be used.

In this case, the coating amount may be about 0.2 to 10 g / m ² in dry weight.

Examples of the support include paper, plastic (for example, polyethylene, polypropylene, polystyrene, etc.) laminated paper, aluminum (including aluminum alloy), metal plates such as zinc and copper, cellulose diacetate, cellulose triacetate. , Plastic films such as cellulose propionate, polyethylene terephthalate, polyethylene, polypropylene, and polycarbonate polyvinyl acetal, paper or plastic films laminated or vapor-deposited with the above metals, steel plates plated with aluminum or chrome. Of these, aluminum and aluminum-coated composite supports are particularly preferred.

Further, it is desirable that the surface of the aluminum material is roughened for the purpose of enhancing water retention and improving adhesion to the photosensitive layer.

Examples of the surface roughening method include generally known brush polishing methods, ball polishing methods, electrolytic etching, chemical etching, liquid honing, sand blasting and the like, and combinations thereof. Among them, the brush polishing method is preferable. Electrolytic etching, chemical etching and liquid honing are mentioned, of which the roughening method involving the use of electrolytic etching is particularly preferred. Further, as the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used, and among these, hydrochloric acid, nitric acid or a salt thereof is particularly contained. Electrolytes are preferred. Further, the surface-roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary. The aluminum plate thus obtained is preferably subjected to anodizing treatment, and particularly preferably, a method of treating with a bath containing sulfuric acid or phosphoric acid can be mentioned. Further, if necessary, surface treatment such as treatment with an alkali silicate or hot water, or immersion in a water-soluble polymer compound or an aqueous solution of potassium fluorozirconate can be performed.

In the present invention, a matte layer is formed on the surface of the photosensitive layer, and the matte layer reacts by exposure to light,
The absorption spectrum in the visible region changes from ultraviolet, and
It contains a compound whose solubility in a developing solution does not change upon exposure (hereinafter referred to as the compound of the present invention).

The above-mentioned mat layer can be formed by applying a coating solution containing a compound of the present invention to a conventionally known matting agent coating solution in which a matting agent is dispersed in a solvent, on the surface of the photosensitive layer. Although any can be used as the above, it is preferable to use water. The application method is also arbitrary, but spray application is preferred.

The compound of the present invention is preferably a compound whose light absorption maximum wavelength is within a range of about 60 nm around the light absorption maximum wavelength of the photopolymerization initiator and whose absorbance is reduced by exposure.

Preferred as these compounds are quinonediazides, and examples thereof include orthobenzoquinonediazide compounds and orthonaphthoquinonediazide compounds.

Preferred quinonediazides are 1,
2-naphthoquinone- (2) -diazide-5-sulfonic acid or 1,2-naphthoquinone- (2) -diazide-4-
Sulfonic acids and their metal salts, ammonium salts, acid chlorides, and 1,2-naphthoquinone- (2) -diazide-5-sulfonic acid or 1,2-naphthoquinone-
(2) -Diazide-4-sulfonic acid and a sulfonic acid ester of a compound having a phenolic hydroxyl group. Of these, particularly preferred are 1,2-naphthoquinone- (2) -diazide-5-sulfonic acid or 1,2-naphthoquinone- (2) -diazide-5-sulfonic acid.
It is a metal salt of 2-naphthoquinone- (2) -diazide-4-sulfonic acid.

In the present invention, the compound of the present invention absorbs light in the initial stage of exposure and suppresses radical generation of the photopolymerization initiator in the photosensitive layer. Since the absorbance is decreased and the radical generation of the photopolymerization initiator is promoted, the image formation is suppressed in the low exposure area and the image formation is normally proceeded in the high exposure area, resulting in a high contrast image. It is thought that it will be obtained.

The compound of the present invention is added to the mat layer in an amount of 0.1 to 0.1%.
It is preferable to add it in the range of 5.0% by weight.

The mat layer of the present invention preferably contains a water-soluble polymer compound. Examples of these water-soluble polymer compounds include polyvinyl alcohol (PV
A) and polyvinylpyrrolidone (PVP) can be preferably used.

Further, the mat layer preferably has an oxygen-blocking property in order to prevent the polymerization inhibiting action of oxygen in the air.

The photosensitive lithographic printing plate of the present invention can be processed by a conventional method.

That is, by exposing through a transparent original image having a line image, a halftone image and the like, and then developing with an aqueous developer, a negative relief image is obtained with respect to the original image. Examples of the active light source suitable for exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a metal halide lamp, and a strobe.

The developing solution for the photosensitive lithographic printing plate of the present invention is not particularly limited, but an alkaline aqueous solution containing substantially no organic solvent is particularly preferable.

"Substantially free of organic solvent" means that the organic solvent is not contained to the extent that it causes problems in hygiene and safety, and that it does not contain any organic solvent. is not. Generally, when the organic solvent contained in the developer composition is 1% by weight or less, these problems do not occur.

From the viewpoint of hygiene and safety, it is preferable that the content of the organic solvent contained in the developer composition is small, and the content of the organic solvent is 0.5% by weight or less, more preferably the organic solvent. It is not to contain at all.

Preferred alkaline agents used in the developing solution include potassium silicate, lithium silicate, sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, and dibasic sodium phosphate. Examples thereof include potassium triphosphate, dibasic potassium phosphate, sodium carbonate, potassium carbonate and the like. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, or sodium silicate has the best development gradation and is most preferable.

In the present invention, the composition of alkali silicate has a molar ratio of [SiO ₂ ] / [M] = 0.5 to 1.5 (where [SiO ₂ ] and [M] are the molar concentrations of SiO ₂ respectively). Represents the molar concentration of the total alkali metal) and S
A developer containing 0.8 to 8% by weight of iO ₂ is preferably used.

Further, a developing solution in which the composition of alkali silicate is [SiO ₂ ] / [M] = 0.5 to 0.75 in molar ratio and SiO ₂ is 0.8 to 4% by weight is , Which is preferable in that the developer waste liquid is easily neutralized due to the low concentration, and [SiO ₂ ] / [M] = 0.75 to 1.3,
In addition, a developer containing 1 to 8% by weight of SiO ₂ is preferable because it has a high buffering power and a high processing capacity.

The pH (25 ° C.) of the developing solution is preferably 12 or more, more preferably 12.5 to 14. Further, water-soluble sulfites such as sodium sulfite, potassium sulfite, lithium sulfite, and magnesium sulfite can be added to the developer. The preferred content of sulfite in the developer composition is 0.
The amount is 05 to 4% by weight, and more preferably 0.1 to 1% by weight.

Further, in the developing solution, Japanese Patent Laid-Open No.
Anionic surfactants, amphoteric surfactants such as those described in JP-A No. 4-75255,
By containing at least one of the nonionic surfactants described in JP-A-60-111246, it is also described in JP-A-55-95946 and JP-A-56-142528. By including the polymer electrolyte as described above, the wettability to the photosensitive layer can be enhanced and the gradation can be further enhanced.
The amount of such a surfactant added is not particularly limited, but is 0.0
It is preferably from 03 to 3% by weight, particularly from 0.006 to 1% by weight
Is preferred.

Furthermore, it is preferable to use an alkali silicate containing 20 mol% or more of all alkali metals in the developer because the generation of insolubles in the developer is reduced, and more preferably 90 mol% or more of potassium is used. Is that
Most preferably, potassium is 100 mol%.

Further, the developer used in the present invention may contain an antifoaming agent. Suitable defoamers include organosilane compounds.

The photosensitive lithographic printing plate of the present invention can be further provided with an overcoat layer. The overcoat layer can be formed by applying an aqueous solution of a water-soluble polymer on the photosensitive layer and drying.

[0063]

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

Example 1 [Preparation of photosensitive lithographic printing plate] An aluminum plate having a thickness of 0.3 mm was electrolytically surface-roughened with hydrochloric acid, anodized with sulfuric acid, and then hydrophilized with sodium silicate. A photosensitive solution having the composition shown in Table 1 was applied onto the support prepared by the treatment so as to have a dry coating amount of 1.6 g / m ² , dried, and then had the composition shown in Table 1. A matting agent dispersion was spray-coated and dried to prepare a photosensitive lithographic printing plate sample 1. In addition, as the matting agent dispersion, Sample 1 was used except that the matting agent dispersion obtained by removing 1,2-naphthoquinonediazide-5-sulfonate sodium from the above matting agent dispersion was used.
A photosensitive lithographic printing plate sample 2 was prepared in the same manner as in.

[0065]

[Table 1] The diazo resin used was synthesized as follows.

<Synthesis of diazo resin> 5.6 g (40 mmol) of p-hydroxybenzoic acid and 17.4 g (60 mmol) of p-diazodiphenylamine sulfate were dissolved in 90 g of concentrated sulfuric acid under ice cooling. 2.7 g of this solution
(90 mmol) p-formaldehyde was added slowly. At this time, the reaction temperature was controlled not to exceed 10 ° C. The reaction solution was stirred for 2 hours and then added dropwise to 1 liter of ethanol, and the generated precipitate was separated by filtration and washed with ethanol. Dissolve the precipitate in 200 ml of pure water, and
An aqueous solution in which 5 g of zinc chloride was dissolved was added. The generated precipitate was filtered, washed with ethanol, and then dissolved in 300 ml of pure water. An aqueous solution in which 13.7 g of ammonium hexafluorophosphate was dissolved was added to this solution. The generated precipitate was separated by filtration, washed with water and ethanol, and then dried at 25 ° C for 1 day to obtain a diazo resin. [Evaluation of photosensitive lithographic printing plate] The obtained photosensitive lithographic printing plate samples 1 and 2 were exposed using a film original containing a step tablet and developed with a developing solution having the following composition to obtain a lithographic printing plate. The number of solid steps and the number of clear steps were calculated.
Also, the gradation was calculated by subtracting the number of solid steps from the number of clear steps. The obtained results are shown in Table 2.

Developer Composition A Potassium Silicate 1160 g Caustic Potassium 133 g Water 5133 ml (pH = 12.7)

[0068]

[Table 2] Example 2 A photosensitive lithographic printing plate sample 3 was prepared in the same manner as in Example 1 except that sodium 1,2-naphthoquinonediazide-5-sulfonate in the composition of the matting agent dispersion was replaced with the following. ~ 13 were created.

Sample 3: 1,2-naphthoquinonediazide-4-sulfonic acid sodium salt Sample 4: 1,2-naphthoquinonediazide-5-sulfonic acid chloride sample 5: 1,2-naphthoquinonediazide-4-sulfonic acid chloride sample 6 : Ester of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and p-hydroxybenzoic acid Sample 7: Ester of 1,2-naphthoquinonediazide-4-sulfonic acid chloride and p-hydroxybenzoic acid Sample 8: 1 , 2-naphthoquinonediazide-5-sulfonic acid chloride and p-hydroxybenzenesulfonic acid ester Sample 9: 1,2-naphthoquinonediazide-4-sulfonic acid chloride and p-hydroxybenzenesulfonic acid ester Sample 10: 1 , 2-naphthoquinonediazide-5-su Ester of phosphonic acid chloride and 2,4,5-trihydroxybenzophenone Sample 11: 1,2-naphthoquinonediazide-4-sulfonic acid ester of ester with 2,4,5-trihydroxybenzophenone Sample 12: 1,2 -Naphthoquinonediazide-5-sulfonic acid chloride and pyrogallol-acetone resin (Mw;
Ester with 2,000 (esterification rate; 20 mol%) Sample 13: 1,2-naphthoquinonediazide-4-sulfonic acid chloride and pyrogallol-acetone resin (Mw;
Ester with 2,000 (esterification rate; 20 mol%) The obtained samples 3 to 13 were evaluated in the same manner as in Example 1. Table 3 shows the obtained results.

[0070]

[Table 3]

[0071]

INDUSTRIAL APPLICABILITY The photosensitive lithographic printing plate of the present invention can shorten gradation without sacrificing sensitivity, can improve the quality of halftone dot image, and has good safelight property. Is.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyuki Ishii, No. 1 Sakuramachi, Hino City, Tokyo Konica Co., Ltd. In-house (72) Inventor Shigeo Tsuji 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Sanryo Kasei Co., Ltd.

Claims (6)

[Claims] 1. A photosensitive layer containing a polymerizable compound having an addition-polymerizable unsaturated bond, a photopolymerization initiator, and an alkali-soluble polymer compound on a support having a hydrophilic surface, and In a photosensitive lithographic printing plate having a matte layer on the surface of the layer, the matte layer contains a compound which reacts upon exposure to change the absorption spectrum in the ultraviolet to visible light region and whose solubility in a developing solution does not change upon exposure. A photosensitive lithographic printing plate characterized in that 2. A compound which reacts upon exposure, changes its absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developer does not change upon exposure, has a maximum absorption wavelength of the photopolymerization initiator. 2. The photosensitive lithographic printing plate according to claim 1, which is a compound having a range of about 60 nm before and after the center and having a reduced absorbance upon exposure. 3. 1,2-naphthoquinone- (2) -diazide-5 is a compound which reacts upon exposure, changes its absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developing solution does not change upon exposure. The photosensitive lithographic printing plate according to claim 1 or 2, which is sulfonic acid or 1,2-naphthoquinone- (2) -diazide-4-sulfonic acid or a metal salt, ammonium salt or acid chloride thereof. . 4. A 1,2-naphthoquinone- (2) -diazide-5-containing compound which reacts upon exposure to light, changes its absorption spectrum in the ultraviolet to visible light region, and whose solubility in a developing solution does not change upon exposure. 3. The photosensitive lithographic printing plate according to claim 1, which is a sulfonic acid ester of sulfonic acid or 1,2-naphthoquinone- (2) -diazide-4-sulfonic acid and a compound having a phenolic hydroxyl group. . 5. A matting agent containing a compound and a water-soluble polymer compound, wherein the matte layer reacts upon exposure to light, the absorption spectrum in the ultraviolet to visible light region changes, and the solubility in a developing solution does not change upon exposure. The photosensitive lithographic printing plate according to claim 1, which is formed from a dispersion liquid. 6. A photosensitive layer containing a polymerizable compound having an addition polymerizable unsaturated bond, a photopolymerization initiator, and an alkali-soluble polymer compound is provided on a support having a hydrophilic surface, and the photosensitive layer surface is provided. By spray coating a matting agent dispersion containing a compound and a water-soluble polymer compound, which reacts upon exposure, changes the absorption spectrum in the ultraviolet to visible light region, and whose solubility in the developer does not change upon exposure A mat layer is provided, and the mat layer is provided.
A method for producing the photosensitive lithographic printing plate described.