JPH04268559A - Damping waterless - Google Patents

Abstract

PURPOSE:To improve shadow reproducibility, the scratch resistance of a silicone rubber layer and printing resistance. CONSTITUTION:When a primer layer, a photosensitive layer and an ink repellent layer are successively formed on a substrate to obtain a damping waterless photosensitive planographic printing plate, the primer layer is subjected to corona discharge treatment under conditions of 1-20W/m<2>/min. A thermoplastic, thermosetting or photosetting resin is used to form the primer layer and a photosetting resin or a photopolymerizable compd. is used to form the photosensitive layer.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a photosensitive lithographic printing plate that does not require dampening water, and more specifically, it improves the adhesion between a primer layer and a photosensitive layer, thereby improving shadow reproducibility and silicone The present invention relates to a photosensitive lithographic printing plate that does not require dampening water and has improved scratch resistance and printing durability of a rubber layer.

0002

BACKGROUND OF THE INVENTION Conventionally, photosensitive lithographic printing plates that do not require dampening water (hereinafter referred to as "plate materials" as necessary) have been known in which a photosensitive layer and an ink repellent layer are sequentially coated on a support. ing. By exposing and developing this plate material, a photosensitive lithographic printing plate that does not require dampening water (hereinafter referred to as "printing plate" as necessary) can be obtained.

Generally, in such plate materials, a primer layer is provided between the support and the photosensitive layer in order to improve the adhesion between them. Various materials are used for the primer layer, such as thermoplastic resins such as polyester resins and acrylic resins, thermosetting resins such as epoxy resins, and photocurable resins containing ethylenically unsaturated compounds. ing.

[0004] However, since such primer layer resins have insufficient adhesion between the primer layer and the photosensitive layer, the primer layer and the photosensitive layer may peel off after development, resulting in poor shadow reproducibility. Furthermore, when printing a large number of sheets, there was a problem in that non-printing areas were missing and printing durability was impaired. In view of the above-mentioned problems, the present inventors have conducted various studies and found that the adhesive force between the primer layer and the photosensitive layer can be further improved by subjecting the primer layer to a corona discharge treatment. The present invention has now been achieved.

[0005]

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide a photosensitive lithographic printing plate that does not require dampening water and is improved in shadow reproducibility, damage to the silicone rubber layer, and printing durability.

[0006]

[Structure of the Invention] The object of the present invention is to provide a photosensitive lithographic printing plate that does not require dampening water and has a primer layer, a photosensitive layer, and a silicone rubber layer in this order on a substrate, in which the primer layer is corona discharged. This is achieved by a photosensitive lithographic printing plate that does not require dampening water.

The configuration of the present invention will be specifically explained below. In the present invention, corona discharge is applied to the primer layer of a photosensitive lithographic printing plate that does not require dampening water, thereby improving the adhesion between the primer layer and the photosensitive layer, resulting in improved shadow reproducibility and silicone rubber layer. It is characterized by improved scratch resistance and printing durability.

The photosensitive lithographic printing plate that does not require dampening water and is used in the present invention can also be used in a type in which only the silicone rubber layer in the image area is removed after development, but it is preferable that the silicone rubber layer in the image area be removed after development. A type in which the photosensitive layer is removed and the primer layer in the image area is exposed is preferable. The method for producing the plate material used in the present invention requires that a primer layer provided on a support is subjected to a corona discharge treatment, and then a photosensitive layer and a silicone rubber layer are sequentially applied.

Examples of the resin used in the primer layer of the present invention include polyester resin, vinyl chloride monovinyl acetate copolymer, acrylic resin, vinyl chloride resin,
Examples include polyamide resin, polyvinyl butyral resin, epoxy resin, acrylate copolymer, vinyl acetate copolymer, phenol resin, phenoxy resin, polyurethane resin, polycarbonate resin, polyacrylonitrile butadiene, polyvinyl acetate, and the like.

[0010] As the anchor agent constituting the primer layer, for example, a silane coupling agent, a silicone primer, etc. can be used, and organic titanates and the like are also effective. Further, a compound that generates an acid upon exposure to light and a dye that changes color or fades due to the acid can be added to this primer layer. The thickness of the primer layer described above is preferably 6 μm or more, particularly preferably 6 μm to 50 μm.

[0011] If the thickness of the primer layer is 6 μm or less, the silicone rubber layer will be scratched if it is rubbed with a hard object such as a developing brush or cloth that has been subjected to impact. On the other hand, if the thickness is 6 μm or more, the above impact and rubbing will be alleviated by the primer layer (cushioning effect).
You will be less likely to get hurt. The photocurable resin contained in the primer layer used in the present invention will be specifically explained.

The diazo resin used as the photocurable resin used in the present invention includes various types, but preferably p-
A diazo resin represented by a condensate of diazodiphenylamine and formaldehyde, which may be water-soluble or organic solvent-soluble, is preferably used in Japanese Patent Publication Nos. 47-1167 and 57-43890. Those that are water-insoluble and soluble in ordinary organic solvents as described in publications are used. Particularly preferred is a diazo resin represented by the following formula 1.

[0013]

[Formula 1]

[In the formula, R1, R2 and R3 are
Represents a hydrogen atom, an alkyl group, or an alkoxy group, and R4
represents a hydrogen atom, an alkyl group or a phenyl group. X represents PF6 or BF4, and Y represents -NH-, -S- or -O-. ]

Examples of the diazo monomer in the diazo resin used in the present invention include 4-diazodiphenylamine, 1-diazo-4-N,N-dimethylaminobenzene, 1-diazo-4-N,N-diethylaminobenzene, and 1-diazo-4-N,N-diethylaminobenzene. -Diazo-4-N-ethyl-N-hydroxyethylaminobenzene, 1-diazo-4-N-methyl-N-hydroxyethylaminobenzene, 1-diazo-2,5-
Diethoxy-4-benzoylaminobenzene, 1-diazo-4-N-benzylaminobenzene, 1-di

001
6] Azo-4-morpholinobenzene, 1-diazo-2,
5-dimethoxy-4-p-tolylmercaptobenzene,
1-Diazo-2-ethoxy-4-N,N-dimethylaminobenzene, p-diazodimethylaniline, 1-diazo-2,5-dibutoxy-4-morpholinobenzene, 1-
Diazo-2,5-diethoxy-4-morpholinobenzene, 1-diazo-2,5-dimethoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-p-tolylmercapbenzene, 1-diazo -4

[0017]-
N-ethyl-N-hydroxyethylaminobenzene, 1
-Diazo-3-ethoxy-4-N-methyl-N-benzylaminobenzene, 1-diazo-3-chloro-4-N,
N-diethylaminobenzene, 1-diazo-3-methyl-4-pyrrolidinobenzene, 1-diazo-2-chloro-
4-N,N-dimethylamino-5-methoxybenzene,
1-diazo-3-methoxy-4-pyrrolidinobenzene,
Examples include 3-methoxy-4-diazodiphenylamine, 3-ethoxy-4-diazodiphenylamine, 3-(n-propoxy)-4-diazodiphenylamine, and 3-(isopropoxy)-4-diazodiphenylamine.

Examples of the aldehyde used as a condensing agent with the diazo monomer include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, and benzaldehyde. Furthermore, regarding anions, water-soluble diazo resins can be obtained by using chlorine ions, tetrachlorozinc acid, etc., and boron tetrafluoride, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid,
, 4'-biphenyldisulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 2
-Me

By using toxy-4-hydroxy-5-benzoyl-benzenesulfonic acid or the like, an organic solvent-soluble diazo resin can be obtained. Particularly preferably, a diazo resin made of hexafluorophosphoric acid is used. In addition to the above-mentioned materials, these photosensitive compositions also contain pigments such as dyes and pigments, sensitizers, plasticizers, surfactants, organic acids, acid anhydrides, and acids that generate upon exposure to light. Compounds that can be used can be added.

(3) Photopolymerizable composition comprising an addition polymerizable unsaturated compound This composition preferably comprises (a) a monomer having at least two terminal vinyl groups, and (b) a photopolymerization initiator. as well as(
c) Consisting of a polymer compound as a binder. As the vinyl monomer of this component (a), Japanese Patent Publication No. 35-509
No. 3, No. 35-14719, and No. 44-28727. For example, polio

Acrylic acid or methacrylic acid ester of alcohol, such as diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, or methylene bis(
meth)acrylamide, bis(meth)acrylamides such as ethylene bis(meth)acrylamide, or unsaturated monomers containing urethane groups;

For example, combinations of diol mono(meth)acrylates such as di-(2'-methacryloxyethyl)-2,4-tolylene diurethane, di-(2-acryloxyethyl)trimethylene diurethane, etc. and diisocyanates. Examples include reaction products. As the photopolymerization initiator of component (b), the compound represented by the above formula 1 can be used, but other types can also be used.

For example, the above-mentioned J. Examples include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, etc., as described in Chapter 5 of "Light Sensitive Systems" by Kosar. More specifically, it is disclosed in British Patent No. 1,459,563.

As the photopolymerization initiator, the following can be used. Benzoin methyl ether, benzoin isopropyl ether, α,α-dimethoxy-
Benzoin derivatives such as α-phenylacetophenone, benzophenone, 2,4-dichlorobenzophenone, o-
Benzophenone derivatives such as methyl benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone,

Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone, anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, α, α -diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound, etc.

Furthermore, as the binder for component (c),
A variety of known polymers can be used. Details of specific binders can be found in U.S. Patent No. 4,072,527.
listed in the number. In addition, the binder used when used in combination with the above-mentioned diazonium salt can be used. These photopolymerizable compositions can contain thermal polymerization inhibitors, plasticizers, dyes, pigments, and the like.

[0027] A liposensitizing agent added to the photosensitive composition;
Additives such as surfactants, sensitizers, stabilizers, thermal polymerization inhibitors, plasticizers, and pigments such as dyes and pigments are generally included in photosensitive coating solutions, although the amounts added vary depending on the type. 0.01% to 20% by weight based on the photosensitive composition,
Preferably, 0.05% to 10% by weight is appropriate. Further, the amount of the photosensitive composition contained in the primer layer is 60% to 100% by weight, preferably 70% to 90% by weight, based on the primer layer.

In the present invention, the corona discharge treatment applied to the primer layer is carried out after coating the primer layer on the support, and the conditions are 1 W/m2/min to 2
00W/m2/min, preferably 5W
/m2/min to 100W/m2/min.

The photosensitive composition used as the photosensitive layer of the photosensitive lithographic printing plate that does not require dampening water according to the present invention contains either a positive-working photosensitive composition or a negative-working photosensitive composition. However, as this negative photosensitive composition, a polymer compound containing an orthoquinonediazide group is mainly used, but the polymer compound containing an orthoquinonediazide group here refers to a compound containing an orthoquinonediazide group. It is used in the meaning of either or both the case of a reaction product with an alkali-soluble resin or the case of a mixture of a compound containing an orthoquinonediazide group and an alkali-soluble resin.

Typical examples will be explained below. Examples of polymeric compounds containing orthoquinonediazide groups include ester compounds of o-naphthoquinonediazide sulfonic acid and polycondensation resins of phenols and aldehydes or ketones.

Examples of the above-mentioned phenols include monohydric phenols such as phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, carvacrol, and thymol, and dihydric phenols such as catechol, resorcinol, and hydroquinone. Examples include trihydric phenols such as hydric phenols, pyrogallol, and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, and furfural. Preferred among these aldehydes are formaldehyde and benzaldehyde.

Further, examples of the above-mentioned ketones include acetone and methyl ethyl ketone. Specific examples of the polycondensation resin include phenol formaldehyde resin, m-cresol formaldehyde resin, m-, o-
Examples include mixed cresol/formaldehyde resin, resorcinol/benzaldehyde resin, and pyrogallol/acetone resin.

The condensation rate of o-naphthoquinonediazide sulfonic acid with respect to the OH group of the phenol of the o-naphthoquinonediazide compound (reaction rate with respect to one OH group) is:
15-80% is preferable, more preferably 20-45%
It is. Further, as the o-quinonediazide compound used in the present invention, compounds described in JP-A-58-43451 can also be used.

As the o-quinonediazide compound used in the present invention, each of the above compounds may be used alone, or two or more compounds may be used in combination. In consideration of coating properties, the o-quinonediazide-containing polymer used in the present invention preferably has a molecular weight of 500 or more, more preferably 1000 or more.

The o-quinonediazide compound described above is preferably used in combination with an alkali-soluble resin. Examples of alkali-soluble resins include novolac resins, vinyl polymers having phenolic hydroxyl groups, and condensation resins of polyhydric phenols and aldehydes or ketones described in JP-A-55-57841. Novolak resin and

For example, phenol-formaldehyde resin, cresol-formaldehyde resin, phenol-cresol-formaldehyde copolycondensation resin as described in JP-A-55-57841, JP-A-55-127553. Examples include copolycondensation resins of p-substituted phenol and phenol or cresol and formaldehyde as described in publications.

The vinyl polymer having a phenolic hydroxyl group is a polymer having a unit having a phenolic hydroxyl group in its molecular structure, and has the following formulas 2 to 6.
Polymers containing at least one structural unit are preferred.

[0038]

[Formula 2]

[0039]

[Formula 3]

[0040]

[Formula 4]

[0041]

[Formula 5]

[0042]

[Formula 6]

[In the formula, R1 and R2 each represent a hydrogen atom, an alkyl group or a carboxyl group, preferably a hydrogen atom. R3 represents a hydrogen atom, a halogen atom, or an alkyl group, preferably a hydrogen atom or an alkyl group such as a methyl group or an ethyl group. R4 represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, preferably a hydrogen atom. A represents an alkylene group which may have a substituent connecting a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer from 0 to 10, and B may have a substituent. Represents a phenylene group or a naphthylene group which may have a substituent. ]

The polymer used in the photosensitive composition of the present invention preferably has a copolymer-type structure, and monomers that can be used in combination with the structural units represented by the above formulas 2 to 6, respectively. As a body unit, for example, ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, isoprene, etc., such as styrene, α-methylstyrene, p-methylstyrene, p
- styrenes such as chlorostyrene, e.g. acrylic acid,
Acrylic acids such as methacrylic acid, unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid, and maleic anhydride, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-chloroethyl acrylate,

[
Esters of α-methylene aliphatic monocarboxylic acids such as phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, and ethyl ethacrylate; nitriles such as acrylonitrile and methacrylonitrile; for example, acrylamide; amides such as acrylanilide, p-chloroacrylamide, m-nitroacrylanilide, m-methoxyacrylanilide, e.g. vinyl acetate,
Vinyl propionate, vinyl benzoate,

[0046]
Vinyl esters such as vinyl butyrate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, isobuty vinyl ether, β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanide, such as 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-
Ethylene derivatives such as dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1-nitroethylene, such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene, N- There are N-vinyl monomers such as vinylpyrrolidone. These vinyl monomers exist in polymer compounds with a structure in which unsaturated double bonds are cleaved.

Among the above monomers, esters of aliphatic monocarboxylic acids and nitriles are preferred because they exhibit excellent performance for the purpose of the present invention. In consideration of coating properties, these alkali-soluble resins preferably have a molecular weight of 5,000 or more, more preferably 10,000 or more.

In addition to the above-mentioned materials, these photosensitive compositions may also contain colorants such as dyes and pigments, fat-sensitizing agents, plasticizers, surfactants, organic acids, acid anhydrides, and other additives that can be added by exposure to light. A compound capable of generating an acid, etc. can be added. There are various positive photosensitive substances used in the present invention, but
Typical examples will be explained below.

(1) Photosensitive composition p- containing diazo resin
The diazo resin represented by the condensate of diazodiphenylamine and formaldehyde may be water-soluble or water-insoluble, but preferably those described in Japanese Patent Publication No. 47-1167 and Japanese Patent Publication No. 57-43890, etc. Those which are water-insoluble and soluble in ordinary organic solvents are used. Particularly preferred is a diazo resin represented by Formula 1 added to the primer layer described above.

Various polymeric compounds can be used as the binder used in combination with the diazonium salt, but monomers having an aromatic hydroxyl group as described in JP-A No. 54-98613 are preferable. , such as N-(4-hydroxyphenyl)acrylamide, N-(4-hydroxyphenyl)methacrylamide, o-, m-, or p-
Copolymers of hydroxystyrene, o-, m-, or p-hydroxyphenyl methacrylate and other monomers,

Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as a main repeating unit as described in US Pat. No. 4,123,276, natural resins such as shellac and rosin, polyvinyl alcohol, US Patent No. 3, 7
51,257, linear polyurethane resins as described in U.S. Pat. No. 3,660,097, phthalated resins of polyvinyl alcohol, condensed from bisphenol A and epichlorohydrin. It contains celluloses such as epoxy resin, cellulose acetate, and cellulose acetate phthalate.

In addition to the above-mentioned materials, these photosensitive compositions also contain pigments such as dyes and pigments, sensitizing agents, plasticizers, surfactants, organic acids, acid anhydrides, and exposure to light. A compound capable of generating an acid can be added. These binders are present in an amount of 40 to 99% by weight in the solid content of the photosensitive composition.
, preferably 50 to 95% by weight. The diazo resin is contained in an amount of 1 to 60% by weight, preferably 3 to 30% by weight. Other dyes, pigments such as pigments, fat-sensitizing agents, plasticizers, surfactants, etc. can be added to these photosensitive compositions.

(2) -CH=C in the main chain or side chain of the polymer
Photosensitive composition containing a polymer compound having an H-CO- group Examples of such a polymer compound include polyesters containing -CH=CH-CO- as a photosensitive group in the main chain or side chain of the polymer; Those mainly composed of photosensitive polymers such as polyamides and polycarbonates (for example, U.S. Patent No. 3
, 030,208, 3,707,373 and 3,453,237);

[0054] Products whose main components are photosensitive polyesters derived from (2-properidene) malonic acid compounds such as cinnamylidene malonic acid and difunctional glycols (
For example, U.S. Patent Nos. 2,956,878 and 3,1
73,787);

Cinnamate esters of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose and the like (eg, US Pat. No. 2,690,966;
Polymers such as those described in the specifications of the same No. 2,752,372, the same No. 2,732,301, etc. can be mentioned. These photosensitive compositions may contain other sensitizers, stabilizers, plasticizers, pigments, dyes, and the like.

(3) Photopolymerizable composition comprising an addition polymerizable unsaturated compound This composition preferably comprises (a) a monomer having at least two terminal vinyl groups, and (b) a photopolymerization initiator. as well as(
c) Consisting of a polymer compound as a binder. As the vinyl monomer of this component (a), Japanese Patent Publication No. 35-509
No. 3, No. 35-14719, and No. 44-28727. For example, polio

Acrylic acid or methacrylic acid ester of alcohol, such as diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc., or methylene bis(meth)acrylate, etc.
meth)acrylamide, bis(meth)acrylamides such as ethylene bis(meth)acrylamide, or unsaturated monomers containing urethane groups;

For example, combinations of diol mono(meth)acrylates and diisocyanates such as di-(2'-methacryloxyethyl)-2,4-tolylene diurethane, di-(2-acryloxyethyl)trimethylene diurethane, etc. Examples include reaction products. As the photopolymerization initiator of component (b), the compound represented by the above formula 1 can be used, but other types can also be used.

For example, the above-mentioned J. Examples include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, etc., as described in Chapter 5 of "Light Sensitive Systems" by Kosar. More specifically, it is disclosed in British Patent No. 1,459,563.

As the photopolymerization initiator, the following can be used. Benzoin methyl ether, benzoin isopropyl ether, α,α-dimethoxy-
Benzoin derivatives such as α-phenylacetophenone, benzophenone, 2,4-dichlorobenzophenone, o-
Benzophenone derivatives such as methyl benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone,

Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone, anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, α, α -diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound, etc.

Furthermore, as the binder for component (c),
A variety of known polymers can be used. Details of specific binders can be found in U.S. Patent No. 4,072,527.
listed in the number. In addition, the binder used when used in combination with the above-mentioned diazonium salt can be used. These photopolymerizable compositions can contain thermal polymerization inhibitors, plasticizers, dyes, pigments, and the like.

Dyes preferably used in the present invention include various pH indicators, basic dyes and oil-soluble dyes. Specifically, Victoria Pure Blue BOH,
Victoria Blue BH, Methyl Violet, Eisen Malachite Green (manufactured by Hodogaya Chemical Industry), Patent Pure Blue VX, Rhodamine.
B, basic dyes such as methylene blue (manufactured by Sumitomo Chemical Industries), and oils such as Sudan Blue II and Victoria Blue F4R (manufactured by B.A.S.F.).
Blue #603, Oil Blue BOS, Oil
Examples include oil-soluble dyes such as Blue IIN (manufactured by Orient Chemical Industries).

In the present invention, a silicone rubber layer is coated on the photosensitive layer. The silicone rubber used in the present invention is preferably a cotton-like or somewhat crosslinked polyorganosiloxane. The polyorganosiloxane usually has a molecular weight of 1,000 to several hundred thousand, and is suitably crosslinked in the form of a liquid, wax, or cake at room temperature. The polyorganosiloxane is classified into condensed type and addition type depending on the method of crosslinking.

[0065] In the condensed type, crosslinking is performed by a condensation reaction, and water, alcohol, organic acid, etc. are released by the reaction. Particularly useful condensation silicone rubbers include:
Examples include mixtures of linear polyorganosiloxanes having hydroxyl groups, acetoxy groups, etc. at both ends or part of the main chain, and silicone crosslinking agents, or those in which hydroxyl groups are reacted with silicone crosslinking agents, and in both cases, a condensation catalyst is added. This is more advantageous in terms of crosslinking speed.

Particularly preferred are those obtained by condensation crosslinking of linear dimethylorganopolysiloxanes having hydroxyl groups at both ends. The main chain of the polyorganosiloxane has a repeating unit represented by the following formula 7.

[0067]

[Formula 7]

In the formula, R1 and R2 are an alkyl group, an aryl group, an alkenyl group, each of which may have a substituent, or a combination thereof, and a methyl group, a phenyl group, a vinyl group, and a trifluoropropyl group are preferable, and in particular, Methyl group is preferred.

As the silicone crosslinking agent, -OCO
CH3, -ONR(R'), -ON=CR(R'),
-OR, -NR(R') or -OH (wherein R and R'
is an alkyl group. ) Condensation type silicone crosslinking agents such as so-called deacetic acid type, deoxime type, dealcoholized type, deaminated type, dehydrated type, and the like, which have a functional group represented by the following formulas, can be mentioned.

Examples of such crosslinking agents include tetraacetoxysilane, methyltriacetoxysilane, ethyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, diethylacetoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane. , dimethyldimethoxysilane, vinyltrimethoxysilane, methyltris(acetoneoxime)silane, methyltris(N-methyl-N-acetylamino)silane, vinyltris(methylethylketoxime)silane,
Examples include methyltri(methylethylketoxime)silane and oligomers thereof.

The amount of each of these crosslinking agents is preferably in the range of 0.5 to 30 parts by weight per 100 parts by weight of the polyorganosiloxane. Examples of the condensation catalyst include organic carboxylic acids, titanate esters, acetylacetone metal complexes, chloroplatinic acid, naphthenic acid, and the like.

The addition type refers to one in which a water-based group in a crosslinking agent is added to an unsaturated group in the main body, such as a vinyl group (-CH=CH2), resulting in crosslinking. Specifically, examples include vinyl group-containing organopolysiloxanes, hydrogenated organopolysiloxanes, and the like mixed with platinum-based catalysts (for example, chloroplatinic acid).

The polyorganosiloxane has repeating units similar to those of the condensed type described above in the main chain. For the silicone rubber layer used in the present invention, either or both of condensation type and addition type silicone rubbers can be used. It is also possible to use condensed and addition type polyorganosiloxanes having hydroxyl groups, unsaturated groups, etc. in one polyorganosiloxane.

In the present invention, an adhesive layer made of acrylic resin or the like may be provided between the photosensitive layer and the silicone rubber layer, and the adhesive layer may contain various reactive crosslinking agents, silane coupling agents, etc. The thickness of the adhesive layer is preferably 0.1 mg/dm2 to 5 mg/dm2.

The support used in the present invention is preferably one that is flexible enough to be set in a normal lithographic printing machine and that can withstand the load applied during printing, such as a metal plate made of aluminum, zinc, copper, steel, etc. and chromium, zinc,
Examples include metal plates plated or vapor-deposited with copper, nickel, aluminum, iron, etc., paper, plastic films, glass plates, resin-coated paper, paper covered with metal foil such as aluminum, and the like. Among these, aluminum plates are preferred. The treatment for the support itself to improve the adhesion is not particularly limited, and includes surface treatments including various surface roughening treatments.

Such surface treatments include, for example, a method of treating the surface of an aluminum plate with a silicate (US Pat. No. 2,714,066), a method of treating the surface of an aluminum plate with an organic acid salt (US Pat. No. 2,714, No. 066), a method of treatment with phosphonic acids and their derivatives (U.S. Pat. No. 3,220,
No. 832), treatment with potassium hexafluorozirconate (U.S. Pat. No. 2,946,683), anodic oxidation, and treatment with an aqueous solution of alkali metal silicate after anodization (U.S. Pat. No. 3, 181,461) etc.

The thickness of each layer constituting the plate material of the present invention is as follows. That is, the support has a thickness of 50 to 400 μm, preferably 100 to 300 μm, and the photosensitive layer has a thickness of 0.05 to 10 μm.
m, preferably from 0.5 to 5 μm, and for the silicone rubber layer from 0.1 to 10 μm, preferably from 0.5 to 2 μm.

In the present invention, a protective layer may be provided on the upper surface of the silicone rubber layer, if necessary. As the material for this protective layer, it is preferable to use a water-soluble film such as polyvinyl alcohol, a biodegradable film such as polyhydroxyalkanoate, or polyesteramide. The plate material of the present invention that does not require dampening water is manufactured, for example, as follows.

[0079] The composition solution to form the primer layer is applied onto the support using a conventional coater such as a reverse roll coater, air knife coater, Meyer bar coater, etc., or a rotary coating device such as Whaler, and is dried and crosslinked. let Next, a composition solution to form a photosensitive layer is applied and dried.

[0080] A silicone rubber solution is applied onto the photosensitive layer in a similar manner and heat-treated for several minutes, usually at a temperature of 100 to 120°C, to sufficiently cure the solution to form a silicone rubber layer. If necessary, a protective film can be provided on the silicone rubber layer using a laminator.

Next, a method for producing a printing plate that does not require dampening water using the plate material that does not require dampening water of the present invention will be explained. A positive film, which is the manuscript, is vacuum-adhered to the surface of the positive plate material and exposed. As a light source for this exposure, a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, etc., which generate abundant ultraviolet light, are used.

Next, the positive film is peeled off and developed using a developer. As the developer, any known developer can be used for plate materials that do not require dampening water, but preferably an aqueous developer is used. The aqueous developer is a developer containing water as a main component, and is described in, for example, Japanese Patent Application Laid-Open No. 61-275759.
Preferably, a developer containing an organic solvent and a surfactant in an amount of 50% to 98% by weight can be mentioned, and more preferably an alkaline agent is included.

Examples of the organic solvents contained in the developer containing water as a main component include aliphatic hydrocarbons (hexane, heptane, Isopar E, H, G (manufactured by Esso Chemical Co., Ltd., aliphatic hydrocarbon products). alcohols (methanol, ethanol, 1-butoxy-2-propanol, 3-methyl- 3-methoxybutanol, β-anilinoethanol, benzyl alcohol, etc.),

[0084]
Ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, dioxane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol dibutyl ether, propylene glycol, dipropylene glycol) butyl ether, tripropylene glycol methyl ether, polypropylene glycol methyl ether, etc.)
,

Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, 4-
methyl-1,3-dioxolan-2-one, etc.), esters (ethyl acetate, propyl acetate, hexyl acetate, methyl acetate, propyl acetate, diethyl succinate, dibutyl oxalate, diethyl maleate, benzyl benzoate, methyl cellosolve acetate) , cellosolve acetate, carbitol acetate, etc.).

As the surfactant added to the developer used in the present invention, anionic surfactants, nonionic surfactants, cationic surfactants and amphoteric surfactants are used. It is also possible to dye the image area simultaneously with development by adding a dye such as crystal violet or astrazonelet to the developer.

Development can be carried out, for example, by rubbing with a developing pad containing a developing solution as described above, or by pouring the developing solution onto the printing plate and then rubbing with a developing brush. By the above development, a printing plate is obtained in which the photosensitive layer and silicone rubber in the unexposed areas are removed, or a printing plate in which the silicone rubber layer is removed and the photosensitive layer is exposed, and the silicone rubber layer remains in the exposed areas.

[0088]

EXAMPLES Example 1 Primer layer dispersion A having the following composition was coated with a wire bar on an aluminum plate that had been anodized and treated with sodium silicate, and dried. This primer layer was cured by irradiating it with 1 J/cm2 of ultraviolet light using a high-pressure mercury lamp.

[Composition of Primer Liquid A] Copolymer of 2-hydroxyethyl methacrylate and methyl acrylate

100 parts by weight fine zinc white (white pigment, manufactured by Sakai Chemical Co., Ltd.)
20 parts by weight Kett Yellow 402 (yellow pigment, manufactured by Dainippon Ink Chemical Co., Ltd.)
10 parts by weight PF6 salt of condensate of p-diazodiphenylamine and formaldehyde

1
0 parts by weight Methyl lactate

560 parts by weight

[Photosensitive liquid composition] Copolymer of 4-hydroxyphenyl methacrylamide, 2-hydroxyethyl methacrylate, and methyl methacrylate
100 parts by weight PF6 salt of condensate of p-diazodiphenylamine and formaldehyde


50 parts by weight Orange IV

5 parts by weight methyl lactate

2000 parts by weight

0
[091] Next, the following silicone rubber liquid was coated on the photosensitive layer so that the coating weight was 20 mg/dm2, and then an 8μ polypropylene film was laminated thereon to prepare a photosensitive lithographic printing plate that did not require dampening water. [Silicone rubber liquid composition] Polydimethylsiloxane with hydroxyl groups at both ends
100 parts by weight methylacetoxysilane
10 parts by weight dibutyltin laurate
1 part by weight Isopar E (manufactured by Esso Chemical Co., Ltd.)
1000 parts by weight

0
[092] After exposing the above plate material to the UGRA resolution chart, the polypropylene cover film was peeled off, and then SDR-1 (6 times diluted, manufactured by Konica) was used.
After being immersed in the developer for 120 seconds, the surface of the plate material was developed by rubbing it with absorbent cotton impregnated with the developer.

Example 2 Primer layer dispersion B having the following composition was coated on a degreased aluminum plate using a wire bar and dried. This primer layer was heated to 0.6 J/cm using a high pressure mercury lamp.
It was cured by irradiation with UV rays.

[Composition of Primer Liquid B] Copolymer of 2-hydroxyethyl methacrylate and methyl acrylate

100 parts by weight fine zinc white (white pigment, manufactured by Sakai Chemical Co., Ltd.)
20 parts by weight Kett Yellow 402 (yellow pigment, manufactured by Dainippon Ink Chemical Co., Ltd.)
10 parts by weight 2,4-diethylthioxanthone (photopolymerization initiator) 5 parts by weight

p-diethylaminobenzoic acid ethyl ester (sensitizer)
5 parts by weight Pentaerythritol triacrylate
100 parts by weight propylene glycol monomethyl ether
Further, the cured primer layer was subjected to a corona discharge treatment as shown in Table 1.

[0096]

[Table 1]

Thereafter, the same photosensitive layer and silicone rubber layer as in Example 1 were provided, and development was carried out in the same manner as in Example 1. Comparative Examples 1 and 2 In Examples 1 and 2, the same photosensitive layer and silicone rubber layer as in Example 1 were provided using the primer layer before being subjected to corona discharge treatment, and development treatment was carried out in the same manner as in Example 1.

In this way, Example 1, Example 2, Comparative Example 1
And the printing plate obtained in Comparative Example 2 was attached to a Heidelberg GTO printing machine from which the dampening water supply device was removed and printed. Table 2 shows the reproducibility of the shadow part of the printed image and the number of prints it can last.
Shown below.

[0099]

[Table 2]

As is clear from Table 2, it can be seen that the samples of the present invention subjected to corona discharge treatment are excellent in shadow reproduction and printing durability.

[0101]

Effects of the Invention In the present invention, since the primer layer is subjected to corona discharge treatment, the adhesion between the primer layer and the photosensitive layer is improved, and the reproducibility in the shadow area is improved. This prevents damage to the product. Further, it has excellent effects such as being able to improve printing durability.

Claims (1)

[Claims] 1. A dampening water-free photosensitive lithographic printing plate comprising a primer layer, a photosensitive layer, and a silicone rubber layer in this order on a substrate, wherein the primer layer is subjected to corona discharge. Photosensitive lithographic printing plate.