JPH0222656A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To enhance image visibility after exposure by incorporating a photosensitive diazo resin, an alkali-soluble polymer, and a compound producing an acid or free radical upon exposure to actinic rays. CONSTITUTION:The photosensitive composition comprises the diazo resin, preferably, a type soluble in an organic solvent, the alkali-soluble polymer, such as a polymer usually having a molecular weight of 2X10<4>-2X10<5> and as the structural units, a monomer, such as acrylamide having an aromatic hydroxyl group, and the compound producing an acid or free radical upon exposure to actinic rays, preferably, the trihaloalkyl compound represented by formula I in which Xa is 1-3C trihaloalkyl; W is N or the like; Z is O or the like; and Y is a nonmetallic atomic group necessary to cyclize W and Z and having a color development group, thus permitting image visibility after the exposure to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photosensitive composition, and particularly to a photosensitive composition suitable for producing a negative-working photosensitive lithographic printing plate.

[Conventional technology]

Photosensitive printing plates are generally produced by coating a photosensitive composition on a support such as an aluminum plate, irradiating it with active light such as ultraviolet rays through a negative image, polymerizing or crosslinking the irradiated areas, and turning the composition into a developer. Insolubilize and elute the non-irradiated areas into a developer, making each area an image area that repels water and accepts oil-based ink, and a non-image area that accepts water and repels oil-based ink. It is obtained by

In this case, the photosensitive composition is particularly suitable for negative type 2
In the 8th edition, diazo resins such as the condensate of P-diazodiphenylamine and formaldehyde have been widely used.

Such a diazo resin generates an acid upon irradiation with actinic rays, and provides an exposed visible image using this acid and a dye whose color fades with the acid.

[Problem to be solved by the invention]

However, with conventional photosensitive compositions, sufficient visible image quality after exposure could not be obtained.

Therefore, the main object of the present invention is to provide a photosensitive composition suitable for a negative-working photosensitive lithographic printing plate, which has improved visible image quality after exposure.

[Means to solve the problem]

The above-mentioned problem can be solved by having a photosensitive diazo resin, an alkali-soluble polymer, and a compound that generates an acid or a free radical upon irradiation with actinic rays.

[Specific structure of the invention]

The present invention will be explained in more detail below.

Photosensitive diazo resin> As the photosensitive diazo resin used in the present invention, conventionally known ones can be used as appropriate. Resins are included, among which diazo resins soluble in organic solvents are preferred.

Examples of the diazo resin include diazo resin inorganic salts which are organic solvent-soluble reaction products of a condensate of p-diazodiphenylamine and formaldehyde or acetaldehyde, and hexafluorophosphate or tetrafluoroborate;
Further, as described in U.S. Pat. Examples include organic solvent-soluble diazo resin organic acid salts which are reaction products such as 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, or salts thereof.

The diazo resin is present in the photosensitive layer in an amount of 1 to 70% by weight, especially 3 to 60% by weight.
It is desirable that the content be % by weight.

Other diazo resins that can be suitably used in the present invention include aromatic compounds having at least one organic group of at least one carboxyl group and at least one hydroxyl group, and diazonium compounds, preferably It is a (co)condensate containing an aromatic diazonium compound as a structural unit.

The above-mentioned aromatic compound having a carboxyl group and/or a hydroxyl group is one which contains an aromatic ring substituted with at least one carboxyl group and/or an aromatic ring substituted with less than one hydroxyl group in the molecule. In this case, the carboxyl group and the hydroxyl group may be substituted with the same aromatic ring.

Preferable examples of the aromatic ring include aryl groups such as phenyl and naphthyl groups.

Further, the above carboxyl, group or hydroxyl group may be bonded directly to the aromatic ring or may be bonded via a joint.

In the above case, the number of carboxyl groups bonded to one aromatic ring is preferably 1 or 2, and the number of hydroxyl groups bonded to one aromatic ring is preferably 1 to 3. Furthermore, examples of joints include alkylene groups having 1 to 4 carbon atoms.

Specific examples of the above-mentioned aromatic compounds containing carboxyl groups and/or hydroxyl groups include benzoic acid, 0-
Chlorobenzoic acid, m-chlorobenzoic acid, p-chlorobenzoic acid, phthalic acid, terephthalic acid, diphenylacetic acid, phenoxyacetic acid, p-methoxyphenylacetic acid, p-methoxybenzoic acid, 2゜4-dimethoxybenzoic acid, 2, 4-dimethylbenzoic acid, p-phenoxybenzoic acid, 4-anilinobenzoic acid, 4-(m-methoxyanilino)benzoic acid, 4
-(p-methoxybenzoyl)benzoic acid, 4-(p-methylanilino)benzoic acid, 4-phenylsulfonylbenzoic acid, phenol, (o, m, p) cresol, xylenol, resorcin, 2-methylresorcin, (o, m
, p)-methoxyphenol, m-ethoxyphenol, catechol, phloroglycin, p-hydroxyethylphenol, naphthol, pyrogallol, hydroquinone,
p-Hydroxybenzyl alcohol, 4-chlororesorcinol, biphenyl 4.4'-diol, 1,2.4-benzenetriol, bisphenol A, 2.4-dihydroxybenzophenone, 2,3.4-trihydroxybenzophenone, p- Hydroxyacetophenone, 4.4
-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylamine, 4,4'-dihydroxydiphenyl sulfide cumylphenol, (o, m, p)-
Chlorophenol, (o, m, p)-bromophenol, salicylic acid, 4-methylsalicylic acid, 6-methylsalicylic acid, 4-ethylsalicylic acid, 6-propylsalicylic acid, 6-laurylsalicylic acid, 6-stialylsalicylic acid, 4.6 -Simethylsalicylic acid, p-hydroxybenzoic acid, 2-methyl-4-hydroxybenzoic acid, 6-methyl-4-hydroxybenzoic acid, 2゜6-dimethyl-4
-Hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, 2,6
-dihydroxybenzoic acid, 2,6-dihydroxy-4-
Benzoic acid, 4-chloro-2,6-dihydroxybenzoic acid, 4-methoxy-2,6-dioxybenzoic acid, gallic acid, phloroglucincarboxylic acid, 2.4.5-trihydroxybenzoic acid, m-galloyl gallic acid, tannic acid, m
-benzoyl gallic acid, m-(p-)ruyl) gallic acid, protocatechoyl gallic acid, 4,6-cyhydroxyphthalic acid, (2,4-dihydroxybenzoic acid) acetic acid,
(2,6-cyhydroxyphenyl)acetic acid, (3,4,5
-) hydroxyphenyl)acetic acid, p-hydroxymethylbenzoic acid, p-hydroxyethylbenzoic acid, 4-(p-
Hydroxyphenyl)methylbenzoic acid, 4-(0-hydroxybenzoyl)benzoic acid, 4-(2,4-dihydroxybenzoyl)benzoic acid, 4-(p-hydroxyphenoxy)benzoic acid, 4-(p-hydroxyanilino) ) benzoic acid, bis(3-carboxy-4-hydroxyphenyl)amine, 4-(p-hydroxyphenylsulfonyl)benzoic acid, 4-(p-hydroxyphenylthio)benzoic acid, etc., and among these, particularly preferred are are salicylic acid, p-hydroxybenzoic acid, p-methoxybenzoic acid, and metachlorobenzoic acid.

For the aromatic diazonium compound forming the constitutional unit of the condensed diazo resin or co-condensed diazo resin mentioned above, for example, diazonium salts such as those listed in Japanese Patent Publication No. 49-48001 can be used, but in particular, Diphenylamine-4-diazonium salts are preferred.

Diphenylamine-4-diazonium salts are derived from 4-amino-diphenylamines, such as 4-amino-diphenylamine, 4-amino-3-methoxy-diphenylamine, 4-amino-diphenylamine, Amino-2-methoxy-diphenylamine, 4'-amino-2-methoxy-diphenylamine, 4'-amino-4-methoxy-diphenylamine,
4-amino-3-methyldiphenylamine, 4-amino-3-ethoxy-diphenylamine, 4-amino-3-
β-Hydroxy-ethoxydiphenylamine, 4-amino-diphenylamine-2-sulfonic acid, 4-amino-
Examples include diphenylamine-2-carboxylic acid, 4-amino-diphenylamine-2'-carboxylic acid, and particularly preferred are 3-methoxy-4-amino-diphenylamine and 4-amino-diphenylamine.

The above-mentioned co-condensed diazo resin and condensed diazo resin can be prepared by a known method, for example, by Photographic Science and Engineering (Photo, Sci.).

Eng., Volume 17, Page 33 (1973), U.S. Patent No. 2,063,631, U.S. Patent No. 2,679,498. It is obtained by polycondensation of salts, aromatic compounds having carboxyl and hydroxyl groups, and aldehydes such as paraformaldehyde, acetaldehyde, benzaldehyde or ketones such as acetone and acetophenone.

Furthermore, these aromatic compounds, aromatic diazo compounds, and aldehydes or ketones having carboxyl groups and/or hydroxyl groups in their molecules can be freely combined with each other, and two or more of each can also be mixed and co-condensed. It is possible.

The molar ratio of the aromatic compound having at least one of a carboxyl group and a hydroxyl group to the aromatic diazo compound is 1:0.1 to 0.1:1; preferably t:O
, S~0.2:1, more preferably l:l~0. :1. In this case, the molar ratio of the sum of aromatic compounds and aromatic diazo compounds having at least one of a carboxyl group and a hydroxyl group to aldehydes or ketones is usually 1:0.6 to 1.2, preferably t. :o
, 7 to 1.5, and reacted at a low temperature for a short time, for example, about 3 hours, to obtain a co-condensed diazo resin.

The counteranion of the diazi resin used in the present invention is:
It contains an anion that stably forms a salt with the diazo resin and makes the resin soluble in an organic solvent.

These include organic carboxylic acids such as decanoic acid and benzoic acid, organic phosphoric acids such as phenyl phosphoric acid, and sulfonic acids; typical examples are methanesulfonic acid, chloroethanesulfonic acid, toticanesulfonic acid, benzenesulfonic acid. , toluenesulfonic acid, mesitylenesulfonic acid, and anthraquinonesulfonic acid, 2-hydroxy-4-
Aliphatic and aromatic sulfonic acids such as methoxybenzophenone-5-sulfonic acid, hydroxysulfonic acid, 4-acetylbenzenesulfonic acid, dimethyl-5-sulfoisophthalate, 2.2', 4.4'-tetrahydroxybenzophenone, 1,2.3-) Hydroxyl group-containing aromatic compounds such as hydroxybenzophenone and 2,2',4-trihydroxybenzophenone, halogenated Lewis acids such as hexafluorophosphoric acid and tetrafluoroboric acid, C
Examples include perhalogen acids such as 114, IQ4, etc.
It is not limited to this. Among these, particularly preferred are hexafluorophosphoric acid, 2-hydroxy-
4-methoxybenzophenone-5-sulfonic acid.

The above-mentioned co-condensed diazo resin can have any molecular weight by varying the molar ratio of each monomer and the condensation conditions, but in order to effectively serve the purpose of the present invention, Molecular weight is approximately 400 to 10,000
Although any number can be used, preferably about 800 to 5,000 is suitable.

Synthesis example of diazo resin-1> 4.43 g of 4-hydroxyphenylmethacrylamide (
0,025 mol) and 22.0 g (0,075 mol) of 4-diazodiphenylamine sulfate at 90° C. under water cooling.
g of concentrated sulfuric acid. 2.7 g (0.09 mol) of paraformaldehyde was added to this solution at a temperature not exceeding 10°C. Thereafter, stirring was continued for 2 hours under water cooling.

This reaction mixture was cooled with water for 17 seconds. of ethanol, and the resulting precipitate was filtered. After thoroughly washing the precipitate with ethanol, the precipitate was dissolved in 200 ml of pure water,
To this solution was added io, sg of an aqueous solution of zinc chloride. The resulting precipitate was filtered, washed with ethanol, and dissolved in 300 ml of pure water. 13.7 g in this liquid
An aqueous solution of ammonium hexafluorophosphate was added. The resulting precipitate was filtered, washed with water, and heated to 30°C.
Then, a co-condensed diazo resin 1 was obtained by drying day and night. When the molecular weight of this co-condensed diazo resin 1 was measured by GPC, the weight average molecular weight was about 2,200.

<Alkali-soluble polymer> The above-mentioned photosensitive diazo resin is used together with an alkali-soluble (or swellable) polymer as a binder.

Examples of this alkali-soluble polymer include copolymers shown in (11 to (b) below) whose structural units are heptamers and which usually have a molecular weight of 20,000 to 200,000.

(1) Acrylamides, methacrylamides, acrylic esters, and methacrylic esters having an aromatic hydroxyl group, such as N-(4-hydroxyphenyl)alkylamide or N-(4-hydroxyphenyl)methacrylamide, 0m- 1p-hydroxystyrene, 0-1m-1p hydroxyphenyl acrylate or methacrylate, (2) acrylic esters and methacrylic esters having aliphatic hydroxyl groups, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, ( 3) α2β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, (4) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, acrylic acid Octyl, 2-chloroethyl acrylate, glycidyl acrylate, N-
(Substituted) alkyl acrylates such as dimethylaminoethyl acrylate, (5) methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate (Substituted) alkyl methacrylates such as (6) acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethylacrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-
Acrylamides or methacrylamides such as hydroxyethyl acrylamide, N-phenylacrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenylacrylamide, (7) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, Vinyl ethers such as butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether, (8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl 7'-F-late, vinyl benzoate, (9) Styrene, α-methylstyrene, Styrenes such as methylstyrene and chloromethylstyrene, 00 Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone, 0υ Olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene, (2) Furthermore, monomers that can be copolymerized with the above monomers may be copolymerized, such as N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylaterile, etc. It also includes, but is not limited to, copolymers obtained by copolymerizing the above monomers and modified with glycidyl methacrylate, glycidyl acrylate, and the like.

More specifically, a copolymer having a hydroxyl group containing the monomers listed in (1) and (2) above is preferable, and a copolymer having an aromatic hydroxyl group is more preferable.

It is particularly preferable that the copolymer contains an α,β-unsaturated carboxylic acid listed in (3), and the preferable acid value of the copolymer is 10 to 100.

The preferred molecular weight of the above copolymer is 40,000 to 150,000.

Further, a polyvinyl butyral resin, a polyurethane resin, a polyamide resin, an epoxy resin, a novolac resin, or a natural resin may be added to the above copolymer as necessary.

This type of alkali-soluble polymer is usually contained in the solid content of the photosensitive composition in an amount of 40 to 99% by weight, preferably 50 to 95% by weight.

On the other hand, particularly preferred as the alkali-soluble polymer as a binder are polymers having methyl acrylate as a structural unit. In this case, more preferred are the following copolymers.

That is, in the molecular structure, +8) a structural unit having an alcoholic hydroxyl group and/or
or 1 to 50 mol% of a structural unit having a phenolic hydroxyl group, (b) the following general formula I,...■ (wherein R1 represents a hydrogen atom or an alkyl group).

5 to 40 mol% of structural units represented by (C) 5 to 40 mol% of units formed from methyl acrylate
, (d) The following general formula ■, -CH2-C-...■ C0OR' (wherein, Ht represents a hydrogen atom, a methyl group or an ethyl group, and R3 represents a group having 2 to 12 carbon atoms. 25 to 60 mol% of structural units represented by alkyl groups or alkyl-substituted aryl groups, and 2 to 30 mol% of structural units having a
It is a copolymer having a weight average molecular weight of 50,000 to 200,000.

Specific examples of monomers forming the structural unit having an alcoholic hydroxyl group include (meth)acrylic acid esters and acrylamides such as compounds shown in the following general formula (■) as described in Japanese Patent Publication No. 527364. can be mentioned.

In the formula, R4 is a hydrogen photon or a methyl group, R5 is a hydrogen atom,
Methyl group, ethyl group or chloromethyl group, and n is 1
Indicates an integer between ~10.

Examples of (meth)acrylic acid esters include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, and examples of acrylamides include N -Methylol (meth)acrylamide, N
-Hydroxyethyl (meth)acrylamide and the like. Preferably it is 2-hydroxyethyl (meth)acrylate.

In addition, examples of the seven polymers forming a structural unit having a phenolic hydroxyl group include N-(4-hydroxyphenyl)-(meth)acrylamide, N-(2-hydroxyphenyl)-(meth)acrylamide, N-( Monomer of (meth)acrylamides such as 4-hydroxynaphthyl)-(meth)acrylamide: 0-lm- or p-hydroxyphenyl (meth)acrylate monomer: Om
- or p-hydroxystyrene monomer. Preferably, the 0-lm- or p-hydroxyphenyl (meth)acrylate monomer is N-(4-e droxyphenyl)-(meth)acrylamide monomer, and more preferably the N-(4-hydroxyphenyl)-(meth)acrylate monomer. ) is an acrylamide monomer.

The structural unit having an alcoholic hydroxyl group and/or the structural unit having a phenolic hydroxyl group is selected from the range of 1 to 50 mol%, preferably 5 to 30 mol%, in the polymer compound.

Examples of the monomer having a cyan group in the side chain forming the structural unit represented by the general formula I include acrylonitrile, methacrylonitrile, 2-pentenenitrile, 2-
Examples include methyl-3-butenenitrile, 2-cyanoethyl acrylate, 0-1m-1p-cyanostyrene, and the like. Preferred are acrylonitrile and methacrylonitrile. The proportion of the structural unit having a cyano group in the side chain contained in the molecule of the polymer compound is selected from the range of 5 to 40 mol%, preferably 15 to 35 mol%.

The unit formed from methyl acrylate is 5 to 40 mol%, preferably 10 to 30 mol% in the polymer compound.
selected from the range.

Examples of monomers having a carboxy ester group in the side chain that form the structural unit represented by the general formula (2) include ethyl acrylate, ethyl methacrylate, propyl acrylate, butyl acrylate, amyl acrylate,
amyl methacrylate, hexyl acrylate, octyl acrylate, 2-chloroethyl acrylate, 2-
Examples include hydroxyethyl acrylate, glycidyl acrylate, and the like. The unit formed from the monomer accounts for 25 to 60 mol%, preferably 3% by mole in the polymer compound.
It is selected from the range of 5 to 60 mol%.

In addition, examples of the seven polymers forming a structural unit having a carboxyl group include methacrylic acid, acrylic acid, maleic anhydride, maleic acid, and the like. The monomer accounts for 2 to 30 mol%, preferably 5 to 15 mol% in the polymer compound.
Selected from the range of mol%.

In addition, each of the above-mentioned structural units is a seven-dimensional structure as a specific example.
It is not limited to units formed from.

As a method for synthesizing an alkali-soluble polymer as a binder in a photosensitive composition, a generally known radical polymerization method or the like may be used, for example, azobisisobutyronitrile,
It is easily synthesized by a solution polymerization method using an initiator (0.1 to 4.0 mol %) such as benzoyl peroxide.

Next, an example of synthesis of an alkali-soluble polymer will be shown.

(Synthesis of alkali-soluble polymer 1) N-(4-hydroxyphenyl) methacrylamide 10
．． 0 g, 25 g of acrylonitrile, 60 g of ethyl acrylate, 5 g of methacrylic acid, and 1.642 g of azobisisobutyronitrile were dissolved in 112 n+1 of an acetone methanol 1:1 mixed solution, and after purging with nitrogen, the solution was heated to 60° C.
heated for an hour.

After the reaction is completed, the reaction solution is poured into water 51 with stirring, and the resulting white precipitate is filtered and dried to obtain 90% alkali-soluble polymer 1.
I got g.

When the molecular weight of this alkali-soluble polymer 1 was measured by gel permeation chromatography (hereinafter abbreviated as GPC), the weight average molecular weight was 85,000.

(Synthesis of alkali-soluble polymer 2) 50.0 g of 2-hydroxyethyl methacrylate.

Acrylonitrile 20g, methyl methacrylate 25g
A mixture of 5 g of methacrylic acid and 1.2 g of benzoyl peroxide was added dropwise over 2 hours to 300 g of ethylene glycol monomethyl ether heated to 100°C. After the dropwise addition was completed, 300 g of ethylene glycol monomethyl ether and 0.3 g of benzoyl peroxide were added, and the mixture was allowed to react for 4 hours. After the reaction was completed, the mixture was diluted with methanol and poured into 5N water with stirring, and the resulting white precipitate was collected by filtration and dried to obtain 90 g of lipophilic polymer compound 2.

When the molecular weight of this alkali-soluble polymer 2 was measured by GPC, the weight average molecular weight was 65,000.

(Synthesis of Alkali-Soluble Polymer 3) A mixture of 45 g of 2-hydroxyethyl methacrylate, 10 g of acrylonitrile, 35 g of ethyl methacrylate, 10 g of methacrylic acid, and 1.2 g of benzoyl peroxide was added to ethylene in the same manner as in the synthesis of Alkali-soluble Polymer 2. The mixture was added dropwise to glycol monomethyl ether to obtain 90 g of alkali-soluble polymer 3.

When the molecular weight of this alkali-soluble polymer 3 was measured by GPC, the weight average molecular weight was 62,000.

Compounds that generate acids or free radicals when irradiated with actinic rays> Compounds that generate acids or free radicals when irradiated with actinic rays used in the present invention include the following general formula (IV
) are preferably used.

General formula [■] (In the formula, Xa represents a trihaloalkyl group having 1 to 3 carbon atoms, W represents N, S, Ss, P, and Z represents OSN%
Indicates S% Ses P. Y represents a group having a chromophore group and consisting of a group of nonmetallic atoms necessary for cyclizing W and Z. ) Specifically, for example, as a trihaloalkyl compound of the general formula (rV), the following general formula (V), (Vl) or [■
] is included.

General Formula (V) B General Formula (VI) A represents a substituted or unsubstituted aryl group or a heterocyclic group, and n is Oll or 2. )゛-Specific exemplary compounds of the compound represented by general formula V) include general formula [■] Xa Xa (wherein, Xa is a trihaloalkyl group having 1 to 3 carbon atoms, B is a hydrogen atom or methyl Oxadiazolated metal compounds containing benzofuran rings such as groups, JP-A-54-7
Examples include 2-trichloromethyl-5-(p-methoxystyryl)-1,3,4-oxadiazole compound described in Japanese Patent No. 4728.

Further, as a specific example of the compound represented by the -11i formula (Vr) or [■], 4-(2,4-dimethoxy4-styryl)-6- ) dichloromethyl-2-pyrone compound, 2.
4-bis-(trichloromethyl)-6-p-methoxystyryl-3-) riazine compound, 2.4-bis-(trichloromethyl)-6-p-dimethylaminostyryl-3
-triazine compounds and the like.

In the present invention, a dye that changes color or fades due to acid or free radicals generated when the above-mentioned compound is irradiated with actinic rays is also used. ], Oil Blue #603 (manufactured by Orient Chemical Industry Co., Ltd.), Patent Pure Blue [manufactured by Sumitomo Mikuni Chemical Co., Ltd.], Crystal Violet, Brilliant Green, Ethyl Violet,
Methyl violet, methyl green, erythrosin B
Triphenylmethane type, diphenylmethane type represented by 1 basic tsukushin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4-p-diethylaminophenyl iminaphthoquinone, cyano-p-diethylaminophenyl acetanilide, etc. Oxidine series, xanthine series, iminonaphthoquinone series, azomethine series or anthraquinone series, leuco dyes and, for example, triphenylamine, diphenylamine, 0-chloroaniline, 1.2.3-) liphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p -bis-dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p'+p -)
Lis-dimethylaminotriphenylmethane, p, p”-
Bis-dimethylaminodiphenylmethylimine, p, p
', p-triamino-0-methyltriphenylmethane,
Examples include primary or secondary arylamine dyes typified by p,p'-bis-dimethylaminodiphenyl-4-anilinonaphthylmethane and p,p',p-)lyaminotriphenylmethane.

Particularly preferred are triphenylmethane-based and diphenylamine-based dyes, more preferably triphenylmethane-based dyes, and especially Victoria Pure Blue BOH.

The above-mentioned dye is usually contained preferably in an amount of about 0.5 to about 10% by weight, more preferably in an amount of about 1 to 5% by weight in the photosensitive composition.

In the photosensitive composition of the present invention, a photopolymerizable monomer and/or a photocrosslinkable binder may be added in an amount of 5% by weight or less to the total composition.

The above-mentioned photopolymerizable monomer is preferably a monomer or oligomer having a boiling point of 100° C. or higher at normal pressure and having at least one addition-polymerizable unsaturated group in one molecule and a molecular weight of 10.000 or lower. Such monomers include oligomers such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and phenoxyethyl(meth)acrylate.
Monofunctional acrylates and methacrylates such as acrylate; polyprolene glycol di(meth)acrylate,
Polypropylene di(meth)acrylate, trimethylolethane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, Hexanediol di(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, polyhydric alcohol such as glycerin or trimethylolethane added with ethylene oxide or propylene oxide and then converted into (meth)acrylate, JP-B No. 1973- No. 41708, Special Publication 1986-1960
34, JP-A-51-37193, urethane acrylates as described in each specification, JP-A-48-6
No. 4183, Special Publication No. 49-43191, Special Publication No. 52-
Examples include polyfunctional acrylates and methacrylates such as polyester acrylates described in each publication of No. 30490, and epoxy acrylates obtained by reacting an epoxy resin with (meth)acrylic acid. For more details, see the Japan Adhesive Association Journal Vol.

20, Na7.300, page 308, polymerizable compounds introduced as photocurable monomers and oligomers can also be used.

In addition, as a photocrosslinkable binder, Japanese Patent Publication No. 59-44
Benzyl (meth)acrylate/(
(meth)acrylic acid/other addition-polymerizable vinyl monomer copolymers as required; methacrylic acid/methyl methacrylate or ester/alkyl methacrylate copolymers as described in Japanese Patent Publication No. 54-34327; others As described in Japanese Patent Publication No. 58-12577, Japanese Patent Publication No. 54-25957, and Japanese Patent Publication No. 54-92723 (
meth)acrylic acid copolymer; allyl (meth)acrylate/as described in JP-A-59-53836;
Pentaerythritol triacrylate is added to (meth)acrylic acid/other addition-polymerizable vinyl monomer copolymers as necessary, and maleic anhydride copolymer described in JP-A-59-71048 by half-esterification. -COOH1POl)! □, -SO,H
l-SO□NH,, 5OJHCO- group, acid value 50
-200 acidic vinyl copolymers and the like.

Furthermore, a main agent for coating, a plasticizer, a fat-sensitizing agent, a stabilizer, etc. can be added to the photosensitive composition of the present invention.

Examples of the coating property improver include alkyl ethers (e.g., ethyl cellulose, methyl cellulose), fluorine-based surfactants, and nonionic surfactants (e.g., Pluronic L-64 (manufactured by Asahi Denka)). Examples of plasticizers for imparting flexibility and wear resistance include butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, and tributyl phosphate. , trioctyl phosphate, tetrahydrofurfuryl oleate, and oligomers of acrylic acid or methacrylic acid. Examples of the oil-sensitizing agent for improving the oil-sensitivity of the image area include JP-A-55-527.
Examples of stabilizers include polyacrylic acid, tartaric acid, phosphoric acid, phosphorous acid, organic acids (acrylic acid, methacrylic acid, , citric acid, oxalic acid, benzenesulfonic acid, naphthalenesulfonic acid, 4-methoxy-2-hydroxybenzophenone-5
-sulfonic acid, etc.). The amount of these additives added varies depending on the purpose for which they are used, but is generally 0.01 to 30% by weight based on the total solid content.

A photosensitive lithographic printing plate is obtained by applying the above photosensitive composition onto the surface of a support and drying it.

Examples of the coating solvent include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, and methyl ethyl ketone.

These solvents may be used alone or in combination of two or more.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating, etc. can be used. The coating amount is preferably 0.2 to Log/rtf based on solid content.

It is preferable to use an aluminum plate as the support for the photosensitive lithographic printing plate of the present invention. The surface is grained by electrolytic roughening in nitric acid or an electrolytic solution containing nitric acid as a main component, or in hydrochloric acid or an electrolytic solution containing hydrochloric acid as a main component, preferably further anodized and sealed if necessary. Use one that has undergone surface treatment such as hole treatment.

Electrolytic surface roughening is carried out by immersing an aluminum plate in a bath containing 0.1 to 0.5 mol/1, preferably 0.2 to 0.4 mol/1 of nitric acid or hydrochloric acid.
Temperature of 0°C, preferably 25-40°C, current density of 20-40°C
It is preferable to perform electrolytic etching at 20 OA/drrf for about 10 seconds to 3 minutes. After this graining treatment, if necessary, a desmut treatment is performed with an aqueous alkali or acid solution to neutralize the material, and the material is washed with water.

The anodizing treatment is performed by electrolyzing using an aluminum plate as an anode using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid, etc. as an electrolyte. The amount of anodic oxide film formed is 1 to 50 mg/d
rrf is appropriate, preferably 10 to 40 mg/di
It is. Here, the amount of anodized film can be determined by, for example, immersing aluminum liquid in a phosphoric acid chromic acid solution (produced by dissolving 35 ml of 85% phosphoric acid aqueous solution and 20 g of chromium oxide (Vl) in 1 part of water). It can be determined by dissolving and measuring the change in weight of the plate before and after the film is dissolved.

Pore sealing treatments include boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and the like. In addition, water-soluble polymer compounds,
Subbing treatment can also be performed using an aqueous solution of a metal salt such as fluorinated zirconate.

The photosensitive lithographic printing plate thus obtained can be used by a known method. Typically, a negative film is brought into close contact with a photosensitive printing plate, exposed to light using an ultra-high pressure mercury lamp, metal halide lamp, etc., and developed using various known developers to obtain a printing plate. The lithographic printing plate produced in this way can be used in sheet-fed and off-wheel printing presses.

That is, by exposing to light through a transparent original having line images, halftone images, etc., and then developing with an aqueous developer,
A negative relief image is obtained for the original image. Light sources suitable for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, and the like.

The developer used in the development of the photosensitive lithographic printing plate of the present invention may be any known developer, but examples include organic solvents such as benzyl alcohol and ethylene glycol monophenyl ether, and alkali metal silicate. and alkaline agents such as organic amine compounds, and those containing water as a main component, those that do not contain organic solvents, and anionic surfactants such as the above alkaline agents, higher alcohol sulfate ester salts and alkylaryl sulfonates. agent,
It is preferable to use one containing an organic carboxylic acid as a main component.

After imagewise exposure of the photosensitive lithographic printing plate of the present invention, if it is brought into contact with the above-mentioned developer or rubbed, the photosensitive layer will be exposed to light after 10 to 60 seconds at about 10 to 40 degrees Celsius. The photosensitive composition in the unexposed areas is completely removed without adversely affecting the areas.

〔Example〕

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

(Example 1) An aluminum plate was degreased with a 3% aqueous sodium hydroxide solution, electrolytically etched in a 2% hydrochloric acid bath at a current density of 25η and 3A/drrf, washed with water, and etched in a 5.3% sulfuric acid bath. Anodic oxidation treatment was carried out for 2 minutes at 30° C. and 1.5 A/dnf. Next, it was sealed with a 1% aqueous sodium metasilicate solution at 85° C. for 30 seconds, washed with water and dried to obtain an aluminum plate for a lithographic printing plate.

A photosensitive lithographic printing plate sample A was obtained by coating this aluminum plate with photosensitive liquid 1 having the following composition so that the film weight after drying was 1.7 g/rrr.

Photosensitive liquid-1 Photosensitive diazo resin-15.0g Alkali-soluble polymer-10.5g (shown in the above synthesis example) 2-trichloromethyl-5.0.2g [β-(2-benzoyl)vinyl] -1 , 3,4-Oxadiazole Victoria Blue BOHO, 1g (manufactured by Odogaya Chemical Co., Ltd.) Jurimer AC-1OL 0.3g (
(manufactured by Nippon Pure Chemical Industries, Ltd.) Methyl cellosolve 100 ml The above photosensitive diazo resin-1 was obtained by the following synthesis.

4.43g of 4-hydroxyphenylmethacrylamide (
0,025 mol) and 22.0 g (0,075 mol) of 4-diazodiphenylamine sulfate were dissolved in 90 g of concentrated sulfuric acid under water cooling. Add 2 paraformaldehyde to this solution.
．． 7 g (0.09 mol) were added in such a way that the temperature did not exceed 10°C. Thereafter, the mixture was kept cooled with water for 2 hours.

This reaction mixture was poured into 11 ethanol under water cooling, and the resulting precipitate was filtered. After thoroughly washing the precipitate with ethanol, the precipitate was dissolved in 200o+1 pure water,
To this liquid was added 10.5 g of an aqueous solution of zinc chloride. After filtering the resulting precipitate, it was washed with ethanol and
It was dissolved in 00ml of pure water. To this liquid was added an aqueous solution in which 13.7 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was filtered, washed with water, and then incubated at 30°C.
Diazo resin 1 was obtained by drying day and night. When the molecular weight of this diazo resin 1 was measured by GPC, the weight average molecular weight was about 2.200.

The resulting photosensitive lithographic printing plate was exposed to a negative transparent original image and a step wedge (optical density increased in steps of 0.150) for 30 seconds from a distance of 601 with a metal halide lamp of 2-2, and then the unexposed areas were exposed. The density difference in the exposed area was measured using a densitometer (densitometer PDA-65 manufactured by Konica Corporation, using a red filter).

It means that the larger the density difference ΔD is, the better the exposed visible image quality is.

(Example 2) In the photosensitive solution of Example 1, 2-trichloromethyl-5
-[β-(2-benzofuryl)vinyl]-1,3,4-
ΔD was similarly measured using 2-(p-methoxystyryl)-4,6-bis(trichloromethyl)-3-triazine instead of oxadiazole.

(Example 3) In the photosensitive solution of Example 1, ΔD was similarly measured using polymer compound-2 instead of alkali-soluble polymer compound-1.

(Comparative Example 1) In the photosensitive solution of Example 1, 2-trichloromethyl-5-
[β-(2-Benzofuryl)vinyl]-1,3,4-oxadiazole was excluded and ΔD was measured in the same manner.

(Comparative Example 2) ΔD was measured in the same manner as in Example 2 except that 2-(p-methoxystyryl)-4,6-bis(trichloromethyl)-S-+-lyazine was removed.

(result) The density difference ΔD on each side was as shown in Table 1.

From the results in Table 1, it can be seen that according to the present invention, the visible image quality after exposure is excellent.

〔Effect of the invention〕

As described above, according to the present invention, the visible image quality after exposure is improved.

Claims (1)

[Claims] (1) A photosensitive composition comprising a photosensitive diazo resin, an alkali-soluble polymer, and a compound that generates acid or free radicals upon irradiation with actinic rays.