JPH11311862A - Photopolymerizable photosensitive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photopolymerizable photosensitive material capable of maintaining sensitivity and good adhesion property between a photosensitive layer and a protective layer, without causing contamination in a non-image part, and without causing defects like crystals of snow even when it is stored for a long time. SOLUTION: This material consists of a photopolymerizable photosensitive layer and a protective layer successively formed on a substrate. The protective layer contains at least (A) a polyvinylalcohol and/or polyvinylalcohol deriv., and (B) a polymer containing vinyl acetate as a copolymerized component but no vinylalcohol. The protective layer contains the component (B) by 0.1 to 2.3 g/m<2> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerizable photosensitive material used for a photosensitive lithographic printing plate or the like.

[0002]

2. Description of the Related Art Conventionally, it has been known to provide a protective layer on a photopolymerizable photosensitive layer for the purpose of blocking oxygen which hinders photopolymerization. For reasons of development and development, polyvinyl alcohol is the most common. In recent years, applications of photopolymerizable photosensitive materials in various fields have been studied, and among them, laser direct plate making in the printing field has been put to practical use. In such a laser direct plate making, a plate is formed using a visible light laser exposure apparatus having an automatic transfer mechanism. Therefore, a protective layer having high scratch resistance so as not to be damaged even in a transfer system is required. To solve this, for example, Japanese Patent Application Laid-Open No. 8-28
JP-A-6379 describes an example of improving scratch resistance by adding polyvinylpyrrolidone, and an example of using polyvinylpyrrolidone and a vinyl acetate copolymer for polyvinyl alcohol. In addition, various performances for the protective layer are required in various other application fields,
Although measures have been taken in response to each, most of them involve mixing polymers having other functions with polyvinyl alcohol, which is the main component.

[0003]

However, as a result of the study by the present inventors, problems such as the occurrence of non-image streaking and poor sensitivity depending on the polymer used in combination, and the formation of snow crystalline Phenomena of causing defects.
This defect is particularly enlarged and increased upon storage, and the image after exposure and development is lost. Accordingly, an object of the present invention is to provide an additional performance required for a protective layer when a photopolymerizable photosensitive material is put to practical use in various fields, that is, contamination of a non-image area of the photosensitive material and reduction in sensitivity. Another object of the present invention is to provide a photopolymerizable photosensitive material which has good adhesion of a protective layer without causing snow crystal defects in the photosensitive layer.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have found that protection is achieved by using polyvinyl alcohol in combination with a specific polymer and controlling the content in a protective layer. The present inventors have found that a photopolymerizable photosensitive material having a layer can achieve the intended purpose, and have completed the present invention.

That is, the gist of the present invention is to provide a photopolymerizable photosensitive material in which a photopolymerizable photosensitive layer and a protective layer are sequentially laminated on a support, wherein the protective layer comprises at least (A) polyvinyl alcohol and / or Or a polyvinyl alcohol derivative,
(B) a polymer containing vinyl acetate as a copolymer component and not containing vinyl alcohol, wherein the protective layer has a component (B) content of 0.1 to 2.3 g / m ^2. Exists in polymerizable photosensitive materials.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Examples of the support in the photopolymerizable photosensitive material of the present invention include metals, plastics, paper, glass, ceramics, and the like. These are used for the purpose of satisfying the adhesiveness with the photosensitive layer and the performance required in each practical field. It is used after surface treatment or various surface treatments. Of these, when used as a photosensitive lithographic printing plate, an aluminum support is particularly preferably used. At this time, the aluminum support is subjected to a surface treatment such as a graining treatment, an anodic oxidation treatment and, if necessary, a sealing treatment.

A known method can be applied to these processes. Examples of the graining method include a mechanical method and an electrolytic etching method. Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid homing, and a buff polishing method. The various methods described above can be used alone or in combination depending on the composition of the aluminum material and the like. Furthermore, the grained aluminum plate is
If necessary, desmutting treatment is performed with an aqueous solution of an acid or an alkali.

[0008] The anodic oxidation treatment is carried out by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution, and using an aluminum plate as an anode for electrolysis. Sealing treatment is boiling water treatment, steam treatment,
Specific examples include sodium silicate treatment and dichromate aqueous solution treatment.

In addition to the above, an aqueous solution of a resin having a cationic quaternary ammonium group, a water-soluble polymer compound such as polyvinylphosphonic acid, starch, cellulose, or a metal salt such as fluorinated zirconic acid, is applied to an aluminum support. A pulling process can also be performed. The photopolymerizable photosensitive layer of the photopolymerizable photosensitive material according to the invention contains an addition-polymerizable compound having at least one ethylenically unsaturated double bond, and a photopolymerization initiator. contains.

In the present invention, an addition-polymerizable compound having at least one ethylenically unsaturated double bond (hereinafter abbreviated as "ethylenic compound") is defined as a photopolymerizable composition which has been irradiated with actinic rays. In the case, a compound having an ethylenic double bond that undergoes addition polymerization by the action of a photopolymerization initiator and cures, for example, a monomer having an ethylenically unsaturated double bond, or a side chain or a main chain Is a polymer having an ethylenically unsaturated double bond. The meaning of the monomer in the present invention is a concept corresponding to a so-called polymer substance. Therefore, in addition to monomers in a narrow sense, dimers, trimers, and oligomers are included.

Examples of the monomer having an ethylenically unsaturated double bond include unsaturated carboxylic acids; esters of aliphatic polyhydroxy compounds with unsaturated carboxylic acids; and those of aromatic polyhydroxy compounds with unsaturated carboxylic acids. ester;
Examples of the ester include an ester obtained by an esterification reaction between an unsaturated carboxylic acid and a polyvalent carboxylic acid and a polyvalent hydroxy compound such as the above-mentioned aliphatic polyhydroxy compound and aromatic polyhydroxy compound.

Examples of the ester of the aliphatic polyhydroxy compound with an unsaturated carboxylic acid include ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol diacrylate, and pentaerythritol. Acrylates such as triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and glycerol acrylate; methacrylates obtained by replacing the acrylate of these exemplified compounds with methacrylate; Itaconic acid ester instead of itaconate and chromate instead of crotonate Phosphate esters, maleic acid esters in which instead of the maleate. Examples of the ester of the aromatic polyhydroxy compound and the unsaturated carboxylic acid include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate, and pyrogallol triacrylate.

Other examples include a phosphate compound having at least one (meth) acryloyl group. The ester obtained by the esterification reaction between the unsaturated carboxylic acid and the polycarboxylic acid and the polyhydroxy compound is not necessarily a single substance, but typical examples include acrylic acid, phthalic acid and ethylene glycol. Condensates; condensates of acrylic acid, maleic acid and diethylene glycol; condensates of methacrylic acid, terephthalic acid and pentaerythritol; condensates of acrylic acid, adipic acid, butanediol and glycerin.

Examples of other ethylenic compounds include:
Urethane acrylates such as the addition reaction of tolylene diisocyanate with hydroxyethyl acrylate; Epoxy acrylates such as the addition reaction of diepoxy compound with hydroxyethyl acrylate; Acrylamides such as ethylene bisacrylamide; Acrylic acid such as diacryl phthalate Esters; vinyl group-containing compounds such as divinyl phthalate are useful.

The polymer having an ethylenically unsaturated bond in the main chain is, for example, a polyester obtained by a polycondensation reaction between an unsaturated divalent carboxylic acid and a dihydroxy compound, and a polymer obtained by mixing an unsaturated divalent carboxylic acid with a diamine. There is a polyamide obtained by a polycondensation reaction. Polymers having an ethylenically unsaturated bond in the side chain are formed by condensation of a divalent carboxylic acid having an unsaturated bond in the side chain, for example, itaconic acid, propylidene succinic acid, ethylidene malonic acid and the like with a dihydroxy or diamine compound. There are polymers. Further, a polymer having a functional group having a reactive activity such as a hydroxy group or a methyl halide group in a side chain, for example, polyvinyl alcohol, poly (2-hydroxyethyl methacrylate), polyepichlorohydrin, etc., and acrylic acid, methacrylic acid, croton A polymer obtained by a polymer reaction with an unsaturated carboxylic acid such as an acid can also be suitably used.

Of the ethylenic compounds described above, acrylate or methacrylate monomers can be particularly preferably used. Next, the photopolymerization initiator will be described. As the photopolymerization initiator, any one capable of initiating the polymerization of the compound having at least one ethylenically unsaturated bond can be used. In particular, any material having photosensitivity to light rays in the visible region can be suitably used. Among them, examples of the activator that generates an active radical by causing some action with the photoexcited sensitizer include hexaarylbiimidazoles, titanocene compounds, halogenated hydrocarbon derivatives, diaryliodonium salts, and organic peroxides. Oxides and the like can be mentioned.
Among them, a system using a hexaarylbiimidazole or a titanocene compound is preferred because sensitivity, storage stability, adhesion of a coating film to a substrate, and the like are good.

As the hexaarylbiimidazoles, various ones can be used.
2'-bis (o-chlorophenyl) -4,4 ', 5
5′-tetra (p-fluorophenyl) biimidazole, 2,2′-bis (o-bromophenyl) -4,
4 ', 5,5'-tetra (p-iodophenyl) biimidazole, 2,2'-bis (o-chlorophenyl)-
4,4 ', 5,5'-tetra (p-chloronaphthyl) biimidazole, 2,2'-bis (o-chlorophenyl)
-4,4 ', 5,5'-tetra (p-chlorophenyl)
Biimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (p-chloro-p-
Methoxyphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole,
2'-bis (o-chlorophenyl) -4,4 ', 5
5′-tetra (o, p-dibromophenyl) biimidazole, 2,2′-bis (o-bromophenyl) -4,
4 ', 5,5'-tetra (o, p-dichlorophenyl)
Biimidazole, 2,2′-bis o, p-dichlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole and the like. These biimidazoles can be used in combination with other kinds of biimidazoles, if necessary. Biimidazoles are described, for example, in Bull. Chem. Soc. Japan,
33,565 (1960) and J.M. Org. Che
m, 36 [16] 2262 (1971).

As the titanocene compound, various compounds can be used. For example, JP-A-59-1523
No. 96, and various titanocene compounds described in JP-A-61-151197 can be appropriately selected and used. More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-
Ti-bis-2,3,4,5,6-pentafluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophenyl-1-yl, Di-cyclopentadienyl-Ti-bis-2,4,
6-trifluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,6-di-fluorophenyl-
1-yl, di-cyclopentadienyl-Ti-bis-
2,4-di-fluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6
-Tetrafluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3 -(Pyr-1-yl) -phenyl-1-yl and the like.

Next, the sensitizer of the photopolymerization initiator will be described. The sensitizer in the present invention means a compound capable of effectively generating an active radical upon irradiation with visible light when coexisting with the above-mentioned activator. Examples of typical sensitizers include, for example, US Pat. No. 3,479,18.
No. 5,549,367, a triphenylmethane-based leuco dye such as leuco crystal violet and leucomalachite green, a photoreducing dye such as erythrosine and eosin Y, and the like. And aminophenyl ketones such as Michler's ketone and aminostyryl ketone disclosed in U.S. Pat. No. 3,652,275, U.S. Pat.
Β-diketones described in US Patent No. 90, indanones found in US Patent No. 4,162,162,
Ketocoumarins disclosed in JP-A-52-112681, aminostyrene derivatives and aminophenylbutadiene derivatives disclosed in JP-A-59-56403, and US Pat. No. 4,594,310. Aminophenyl heterocycles, US Pat. No. 4,966,83
Jurolidine heterocycles disclosed in JP-A No.
And pyromethene dyes described in JP-A-241338.

Further, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 3-mercapto-1,2,4-triazole, if necessary, are added to the photopolymerization initiator used in the present invention.
By adding a hydrogen-donating compound such as N-phenylglycine or an alkyl N, N-dialkylbenzoate, the photopolymerization initiation ability can be further enhanced. Of these, particularly preferred are compounds having a mercapto group such as 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 3-mercapto-1,2,4-triazole.

Next, the polymer binder will be described. This is a component that imparts a film forming ability and a viscosity adjusting ability, and preferably includes a polymer binder having a carboxyl group in the molecule. Specific examples thereof include homo- or copolymers of (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, maleic acid, (meth) acrylonitrile, styrene, vinyl acetate, vinylidene chloride, maleimide and the like. And polyethylene oxide, polyvinyl pyrrolidone, polyamide, polyurethane, polyethylene terephthalate, acetyl cellulose, polyvinyl butyral, and the like.

Among them, a copolymer containing at least one (meth) acrylic ester and (meth) acrylic acid as a copolymer component is preferable. The preferred acid value of the polymer binder is from 10 to 250, and the preferred weight average molecular weight (hereinafter abbreviated as Mw) is from 5,000 to 500,000. These polymer binders preferably have an unsaturated bond in a side chain, and particularly preferably have at least one type of unsaturated bond represented by the following general formulas (1) to (3).

[0023]

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(Wherein, R ¹ represents a hydrogen atom or a methyl group. R ^{2 to} R ⁶ each independently represent a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, Having a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent An optionally substituted aryloxy group, an optionally substituted alkylamino group, an optionally substituted arylamino group, an optionally substituted alkylsulfonyl group, or a substituent An arylsulfonyl group optionally having
Represents an oxygen atom, a sulfur atom, an imino group, or an alkylimino group. )

The substituent such as an alkyl group which may have a substituent is not particularly limited as long as the reactivity of the carbon-carbon double bond is not extremely reduced, but is usually a halogen atom, an alkyl group or a phenyl group. Group, a cyano group, a nitro group, an alkoxy group, an alkylthio group, a dialkylamino group, or the like. Among them, as those represented by the formula (1), R ¹ is a hydrogen atom or a methyl group;
More preferably, R ² and R ³ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a dialkylamino group, or a cyano group, and those represented by the formula (2) include R ² and R 3 ³ is each independently a hydrogen atom, a halogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group or a cyano group, and R ⁵ is a hydrogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group, or a cyano group. , R ⁵ and R ⁶ are more preferably each independently a hydrogen atom, a halogen atom or a lower alkyl group, and those represented by the formula (3)
More preferably, each of ² , R ³ and R ⁴ independently represents a hydrogen atom, a halogen atom, a lower alkyl group, a carboxyl group, an alkoxycarbonyl group or a cyano group. Further, in formula (1), at least two of R ^{1 to} R ³ are hydrogen atoms because of the easiness of the addition reaction of the carbon-carbon double bond in the above formulas (1) to (3). In (2) and (3), those in which at least two of R ^{2 to} R ⁴ are hydrogen atoms are particularly preferred.

There are roughly the following two methods for synthesizing these compounds. (Synthesis Method 1) An inert organic solvent solution of a polymer binder having a carboxyl group in a molecule (for example, alcohol-based, ester-based, aromatic hydrocarbon-based, aliphatic hydrocarbon-based, etc.) and an epoxy group About 80-
A method of synthesizing by reacting at 120 ° C. for about 1 to 50 hours. The ratio of the carboxyl group to be reacted with the epoxy group-containing unsaturated compound is not particularly limited as long as the effect of the present invention can be achieved, but it is preferable to react 5 to 90 mol% to all the carboxyl groups, more preferably Is 20 to 80 mol%, more preferably 30 to 70 mol%. Within the above range, the developing property is good and the adhesive property is good.

The epoxy group-containing unsaturated compound used in the production of the ethylenic polymer binder having an unsaturated group in the side chain includes:
A compound having at least one addition-polymerizable unsaturated bond and an epoxy group in one molecule. Examples of the epoxy group-containing unsaturated compound include glycidyl (meth) acrylate, allyl glycidyl ether, α-ethylglycidyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, monoalkyl itaconate monoglycidyl ester, Examples thereof include aliphatic epoxy group-containing unsaturated compounds such as fumaric acid monoalkyl ester monoglycidyl ester and maleic acid monoalkyl ester monoglycidyl ester, and alicyclic epoxy group-containing unsaturated compounds represented by the following structure.

[0028]

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[0029]

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(In each formula, R ⁸ represents a hydrogen atom or a methyl group. R ⁹ represents a divalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. R ¹⁰ represents a C 1 to C ¹⁰ aliphatic hydrocarbon group.) It represents a divalent hydrocarbon group, and k represents an integer of 0 to 10.) Specific examples of preferred compounds of the epoxy group-containing unsaturated compound include glycidyl methacrylate, allyl glycidyl ether, and 3,4-epoxycyclohexyl. Methyl acrylate and the like can be mentioned. Among these, particularly preferred compounds are allyl glycidyl ether and 3,4-epoxycyclohexylmethyl acrylate.

(Synthesis Method 2) An unsaturated bond having low reactivity as shown in the general formulas (2) and (3) is
A method of synthesizing a compound having two or more kinds of unsaturated bonds, which is one kind or more, and one kind of unsaturated bond having higher reactivity, and an unsaturated carboxylic acid. Specific examples of the compound having an unsaturated group represented by the general formula (2) include allyl (meth) acrylate, 3-allyloxy-2-hydroxypropyl (meth) acrylate, N, N-diallyl (meth) acrylamide, cinnamyl (Meth) acrylate, crotonyl (meth) acrylate, methallyl (meth) acrylate, and the like. Of these,
Allyl (meth) acrylate is particularly preferred.

Specific examples of the compound having an unsaturated group represented by the general formula (3) include vinyl (meth) acrylate, vinyl crotonate, 1-propenyl (meth) acrylate, 1-chlorovinyl (meth) acrylate, 2
-Phenyl vinyl (meth) acrylate, vinyl (meth) acrylamide and the like. Of these, vinyl (meth) acrylate is particularly preferred.

By copolymerizing these monomers with an unsaturated carboxylic acid, preferably acrylic acid or methacrylic acid, a copolymer having the unsaturated group is obtained. As the monomer to be copolymerized, another monomer may be copolymerized in addition to the unsaturated carboxylic acid, and examples thereof include alkyl acrylate, alkyl methacrylate, acrylonitrile, and styrene. The ratio of the compound having the structure of (2) or (3) to the total components of the polymer to be copolymerized is 10 to 10%.
90 mol%, more preferably 30 to 80 mol%. If it is less than this range, the image reproducibility is poor, and if it is too large, the developability deteriorates.

A particularly preferred example of the polymer binder is a compound in which a part of the carboxyl group of a polymer having a carboxyl group in the molecule is reacted with an unsaturated compound having an alicyclic epoxy group. The main components of the photopolymerizable composition for forming the photosensitive layer have been described in detail above, but the preferred usage ratio thereof is 100 parts by weight of the polymerizable ethylenically unsaturated compound. ,
The sensitizer is preferably 0.01 to 20 parts by weight, particularly preferably 0.05 to 10 parts by weight, and the activator is preferably 0.1 to 10 parts by weight.
The amount is from 80 to 80 parts by weight, particularly preferably from 0.5 to 50 parts by weight, and the amount of the polymer binder is preferably from 10 to 400 parts by weight, particularly preferably from 20 to 200 parts by weight.

The photopolymerizable composition may further contain other substances in addition to the above-mentioned components, depending on the purpose of use. For example, thermal polymerization inhibitors such as hydroquinone, p-methoxyphenol, 2,6-di-t-butyl-p-cresol; coloring agents comprising organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate, tricresyl Additives such as plasticizers such as phosphates, sensitivity characteristic improvers such as tertiary amines and thiols, and other dye precursors can also be added. Preferred amounts of the various additives described above are 2 parts by weight or less of a thermal polymerization inhibitor, 20 parts by weight or less of a coloring agent, 40 parts by weight or less of a plasticizer, and 30 parts by weight of a dye precursor based on 100 parts by weight of an ethylenic compound. In general, the range is as follows.

The photopolymerizable composition described above is diluted with an appropriate solvent, applied on the support, dried and applied as a photosensitive layer. As a coating method, coating can be performed by a known method such as dip coating, coating rod, spinner coating, spray coating, and roll coating. The dry coating film thickness is about 0.1 to 20 g / m ² , and 0.5 to 3 g when used as a photosensitive lithographic printing plate.
/ M ² is preferred.

On the photopolymerizable photosensitive layer of the photopolymerizable photosensitive material of the present invention, a protective layer is provided as an oxygen blocking layer for preventing a polymerization inhibiting action by oxygen. The protective layer of the present invention contains (A) polyvinyl alcohol and / or a polyvinyl alcohol derivative, and (B) a polymer containing vinyl acetate and not containing vinyl alcohol as a copolymerization component. B) from 0.1 to 2.
It is characterized by having 3 g / m ² .

The polyvinyl alcohol as the component (A) can be obtained by saponifying polyvinyl acetate with an alkali, an acid, aqueous ammonia or the like. The weight average molecular weight of the polyvinyl alcohol in the present invention is preferably from 2,000 to 500,000, more preferably from 0.4000 to 100,000. The saponification degree of polyvinyl alcohol is 70 to 99.
mol%, more preferably 85 to 85 mol%.
95 mol%. If the saponification degree is smaller than the above range, the solubility in water or alkaline water tends to be poor, and the developability tends to be poor. If the saponification degree is larger than the above range, the effect of the present invention cannot be sufficiently exerted.

The weight average molecular weight and the degree of saponification are within the above ranges, and are soluble in water or a mixture of water and an alcohol such as methanol, ethanol, propanol or isononyl alcohol, or a water-miscible organic solvent such as tetrahydrofuran. Derivatives of polyvinyl alcohol can also be used. Examples of such derivatives include, for example, partially acetalized polyvinyl alcohol, modified polyvinyl alcohol cation-modified with a quaternary ammonium salt, and anion-modified one with sodium sulfonate. Further, one or more of the above-mentioned polyvinyl alcohols and derivatives thereof may be used in combination.

In the present invention, the polymer (B) containing vinyl acetate as a copolymer component and not containing vinyl alcohol is different from the above-mentioned component (A) in that it does not contain vinyl alcohol as a copolymer component. Is clearly distinguishable, and the polymer (B) needs to be soluble in water or a mixture of water and a water-miscible organic solvent in consideration of the development described below. In this regard, the component copolymerized with vinyl acetate preferably contains a certain amount or more of a water-soluble component. Examples of the water-soluble component include vinylpyrrolidone, carboxy-containing compounds such as unsaturated carboxylic acids such as (meth) acrylic acid and itaconic acid and derivatives thereof, and hydroxy-containing compounds such as hydroxyethylmethacrylamide. The proportion of the water-soluble component in the copolymer (B) is usually 50 to 97 mol%, preferably 60 to 9 mol%.
5 mol%.

The proportion of vinyl acetate in the copolymer (B) is usually 3 to 50 mol%, preferably 5 to 40 mol%.
mol%. When the amount is less than this, the effect of vinyl acetate described later is not sufficiently exhibited, and when it is more than this, the solubility in water is inferior, which causes trouble during development. In addition, as long as the above components are ensured, other copolymerizable components can be used for the purpose of imparting necessary performance to the copolymer (B).

The role of vinyl acetate in the copolymer (B) is to make it compatible with polyvinyl alcohol and / or its derivative (A). Polyvinyl alcohol is originally a polymer having a very high crystallinity, and has poor compatibility with other kinds of polymers. In this state, if various polymers are mixed for the purpose of imparting performance as a protective layer, a sea-island structure of polymers having different shrinkage ratios is generated in the protective layer film. It is considered that if the film is in a dry state in this state, a gap due to a difference in shrinkage causes a load on the surface of the photosensitive layer to cause a snow crystal defect in the photosensitive layer. Vinyl acetate is an unavoidable component in polyvinyl alcohol, and it is considered that the problem of the above-mentioned defect can be solved by including vinyl acetate as a common component in a polymer to be mixed.

The polymerization average molecular weight of the polymer (B) containing vinyl acetate as the copolymerization component can vary depending on the component to be copolymerized, but is preferably from 2,000 to 500,000.
More preferably, it is from 30,000 to 200,000. If it is smaller than the above range, the strength of the protective layer will be weak, and if it is larger, water solubility tends to be deteriorated. The polymer (B) containing vinyl acetate as the copolymer component can be used alone or in combination of one or more.

In the present invention, the ratio of (A) to the total of component (A) and component (B) in the protective layer is from 25 to 95% by weight, more preferably from 50 to 90%. If it is less than 25%, there is a fear that the sensitivity may decrease.
If it is more than 5% by weight, the properties such as adhesiveness, sensitivity and developability that are to be imparted by the combined use of the component (B) are not sufficiently exhibited.

[0045] In the present invention, the content of the protective layer (B) must be 0.1~2.3g / m ^2, preferably 2.1 g / m ² or less. If the ratio is larger than this, even if the above-mentioned ratios (A) and (B) are satisfied, development failure occurs, which is not preferable. A preferred lower limit is 0.5 g / m ² or more. If the amount is too small, there is a fear that effects such as adhesiveness may be insufficient.

The content of (A) in the protective layer must be preferably 1 g / m ² or more, and more preferably 1.5 g / m ^2.
(B) Even if the ratio is satisfied, the sensitivity is lowered, which is not preferable. Also, usually less than 10 g / m ² , preferably 7 g / m ²
Is less than. In the protective layer of the present invention, in addition to the above components, other substances can be added and mixed according to the purpose of use. For example, nonionic surfactants such as polyoxyethylene alkylphenyl ether, anionic surfactants such as sodium dodecylbenzenesulfonate, cationic surfactants such as lauryltrimethylammonium chloride, other antifoaming agents, dyes, plasticizers, p
H regulator and the like. The preferable content of the various additives described above is 10% by weight or less, more preferably 5% by weight or less in the protective layer.

The dry film weight of the protective layer of the present invention is 1 g / m ^2.
And more preferably 10 g / m ² or less, more preferably ² g / m ² or less.
７7 g / m ² . If it is less than 1 g / m ² , the sensitivity of the photopolymerizable photosensitive material will be low, while if it exceeds 10 g / m ² , the developability will deteriorate, which is not preferable. The protective layer of the present invention is applied by dissolving in water or a mixed solvent of water and a water-miscible organic solvent, coating the photosensitive layer, and drying. As a coating method, it is possible to apply a known coating method similarly to the photosensitive layer.

As the exposure light source of the photopolymerizable photosensitive material of the present invention obtained as described above, a known exposure light source is applied, for example, a carbon arc, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, Tungsten lamps, halogen lamps, helium cadmium lasers, argon ion lasers, YAG lasers, helium neon lasers and the like can be mentioned, but those using laser light are particularly preferred.

The photopolymerizable material of the present invention is developed with a developing solution after exposure with such a light source. Examples of the components of the developer include an alkali agent, an organic solvent, and a surfactant, but are not limited thereto. The development is performed by a known method such as dip development or spray development, and the protective layer alone may be removed in advance with water or the like before processing with a developer. Further, if necessary, a heat treatment may be performed before development by a known method for the purpose of stabilizing an image. Further, re-exposure may be performed after development for the same purpose.

[0050]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Was coated and dried to a dry thickness of 2 g / m ² using a bar coater Examples 1-2 and Comparative Examples 1-5 below photopolymerizable photosensitive layer coating solution-1 below the support 1. Further, the following protective layer coating solutions-1 to 6
Was applied and dried using a bar coater at the dry film thicknesses shown in Table 1 to prepare photosensitive lithographic printing plates 1 to 7. The indoor environment at the time of applying the protective layer was 20 ° C. and 40%. The following items were evaluated about the obtained photosensitive lithographic printing plate. Table 1 shows the results.

Photopolymerizable Photosensitive Layer Coating Solution-1 5 parts by weight of PM-25 manufactured by Nippon Kayaku Co., Ltd. 25 parts by weight of UA-306H manufactured by Shin-Nakamura Chemical Co., Ltd. DPHA 25 manufactured by Nippon Kayaku Co., Ltd. 40 parts by weight of the following polymer binder-1 40 parts by weight of the following polymer binder-2 5 parts by weight of the compound of the following structure (A) 2.0 parts by weight 10 parts by weight of the titanocene compound of the following structure (B) 2-mercapto Benzothiazole 5.0 parts by weight N, N-dimethylbenzoic acid ethyl ester 10 parts by weight Copper phthalocyanine pigment 3.0 parts by weight Cyclohexanone 1090 parts by weight

[0052]

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[0053]

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[0054]

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[0055]

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Synthesis of Polymeric Binder-1 Methyl methacrylate / isobutyl methacrylate / isobutyl acrylate / methacrylic acid = 35/20 /
10/35 mol% (charge ratio) copolymer, Mw = 7
200 parts by weight (hereinafter abbreviated as "stem resin-1"), 75 parts by weight of the following alicyclic epoxy-containing unsaturated compound, 2.5 parts by weight of p-methoxyphenol, 8 parts by weight of tetrabutylammonium chloride, propylene Glycol monomethyl ether acetate (800 parts by weight) is added to the reaction vessel, and the mixture is stirred and reacted in air at 110 ° C. for 24 hours to polymer binder-1 (oxidation 60, 60% of the total methacrylic acid component of the trunk resin-1). Was reacted with an unsaturated group.

[0057]

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Synthesis of Polymeric Binder-2 Copolymer of α-methylstyrene / acrylic acid (trade name “SCX-690” manufactured by Johnson Corporation, oxidation 240,
(Mw = 15,000), 855 parts by weight, the following alicyclic epoxy-containing unsaturated compound (490 parts by weight), p-methoxyphenol 1.3 parts by weight, tetraethylammonium chloride 4.3 parts by weight, propylene glycol monomethyl ether acetate 1800 Parts by weight are added to the reaction vessel.
The polymer binder is reacted by stirring at 0 ° C. for 15 hours in the air.
2 (about 170 oxidations, about 50% of the total methacrylic acid component of SCX-690 reacted with unsaturated groups).

[0059]

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[0060]Coating solution for protective layer-1 to 7 Protective layer components in Table 1 10 parts by weight NC-95 (manufactured by Lion Corporation, surfactant) 0.02 parts by weight Water 87 parts by weight Ethanol 3 parts by weight Support-1 Degreasing the aluminum plate with 3% sodium hydroxide
This was placed in a 18.0 g / l nitric acid bath at 25 ° C. and 80 A / dm 2.
Etching for 15 seconds at a current density of
Desmut treatment with 5% aqueous sodium hydroxide for 5 seconds
And then neutralized with a 10% aqueous nitric acid solution at 25 ° C. for 5 seconds.
After washing in a 30% sulfuric acid bath at 30 ° C and 10 A / dm2
For 16 seconds, wash with water and dry to obtain Support-1
Was.

<Storage stability under drying> After storing the photosensitive lithographic printing plate in a warehouse at a temperature of 20 ° C. and a humidity of 30% for 3 months, an argon laser (light quantity 130 μJ / cm ² , wavelength 488 n) was used.
m), solid exposure was performed on the entire surface. After that, the automatic developing machine HL
Using -860X (manufactured by Mitsubishi Chemical Corporation), development processing was performed with the following developer 1, and the state of the image after development was confirmed.
When a snowflake-like defect was visually observed, it was judged as x, and when none was observed, it was judged as o. The developer temperature is 30
C., the transfer speed was 60 cm / min.

<Developability> The unexposed photosensitive lithographic printing plate was developed with the following developer 1 using an automatic developing machine HL-860X (manufactured by Mitsubishi Chemical Corporation), and developed ink PI
-2 (Fuji Photo Film Co., Ltd.)
The degree of dirt was evaluated. The evaluation criteria were "○;
X: stained with ink ". The developer temperature was 30 ° C.
The transfer speed was 120 cm / min. This is twice the normal speed, and can be said to be more severe development conditions.

<Tape Peeling Test> In order to evaluate the adhesion between the photosensitive layer and the protective layer of the photosensitive lithographic printing plate, a cellophane tape (manufactured by Lion Corporation) was adhered to the protective layer and rubbed 10 times with a finger. Peeled in 180 degree direction. It was evaluated whether the protective layer was peeled off together with the cellophane tape. Evaluation criteria are
"O: No peeling, X: Peeled". <Sensitivity> After exposing the photosensitive lithographic printing plate using a diffraction spectral irradiation apparatus (RM-23, manufactured by Narumi), an automatic developing machine HL-
860X (manufactured by Mitsubishi Chemical Corporation) using the following developer
The developing process was performed in step 1, and the amount of energy required for photocuring with a light amount of a wavelength of 488 nm was determined from the height of the obtained cured image. The developer temperature was 30 ° C. and the transport speed was 60 cm.
/ Min.

Developer-1 Potassium silicate (JIS A potassium silicate) 3% by weight Perex NBL (manufactured by Kao Corporation) 5% by weight (sodium alkylnaphthalene sulfonate; content 35%) Water 92% by weight

[0065]

[Table 1]

The components of the protective layer in Table 1 are as follows. Gohsenol GL-03 (polyvinyl alcohol manufactured by Nippon Synthetic Chemical Co., Ltd.): weight average molecular weight = 17,000 polyvinylpyrrolidone: weight average molecular weight = 40,000 vinylpyrrolidone / vinyl acetate (mol ratio = 7/3)
Copolymer: weight average molecular weight = 40,000 acrylic acid / p-hydroxyphenyl methacrylamide / vinyl acetate (mol ratio = 6/2/2) Copolymer: polymerization average molecular weight = 30,000 acrylic acid / p-hydroxyphenyl methacryl Amide (mol ratio = 7/3) copolymer: polymerization average molecular weight = 3
Ten thousand

[0067]

According to the present invention, it is possible to maintain the sensitivity, the good adhesion between the photosensitive layer and the protective layer, to prevent the non-image area from being stained, and to cause snow crystal defects even after long-term storage. A photopolymerizable light-sensitive material free from defects has been made possible.

Claims (6)

[Claims] 1. A photopolymerizable photosensitive material comprising a support, on which a photopolymerizable photosensitive layer and a protective layer are sequentially laminated, wherein the protective layer comprises at least (A) polyvinyl alcohol and / or a polyvinyl alcohol derivative. And (B) a polymer containing vinyl acetate as a copolymer component and not containing vinyl alcohol, and the protective layer has a component (B) content of 0.1 to 2.3 g / m ^2. Photopolymerizable photosensitive material. 2. The film weight of the protective layer exceeds 1 g / m ² ,
^{2. The} photopolymerizable photosensitive material according to claim 1, wherein the amount is 0 g / m ² or less. 3. The method according to claim 2, wherein the proportion of vinyl acetate in (B) is 3 to 50.
3. The photopolymerizable light-sensitive material according to claim 2, wherein the amount is mol%. 4. The photopolymerizable photosensitive material according to claim 1, wherein the ratio of (A) to the total of (A) and (B) is 25 to 95% by weight. 5. The photopolymerizable photosensitive layer contains a polymer binder, an addition-polymerizable compound having at least one ethylenically unsaturated double bond, and a photopolymerization initiator.
The photopolymerizable photosensitive material according to any one of the above. 6. The photopolymerizable photosensitive material according to claim 5, wherein the photopolymerization initiator contains a hexaarylbiimidazole or a titanocene compound.