JP2000267292A - Photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high sensitivity photosensitive planographic printing plate protected from surface scuffing in a step for piling up product plates, during transportation or at drawing out in a plate setter (photolithography machine) without using a slip sheet or a film for laminating, free from the stain of the non-image area and the drop-out of the image area and sensitive to visible laser light. SOLUTION: The photosensitive planographic printing plate has a photopolymerizable photosensitive layer on the anodic oxide film of an aluminum substrate with the anodic oxide film on at least one side, an overcoat layer on the photosensitive layer and a back coat layer on the rear side of the substrate opposite to the photosensitive layer. The coefficient of friction of the overcoat layer and the back coat layer is 0.2-0.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on an aluminum support. It concerns printing plates.

[0002]

2. Description of the Related Art Hitherto, many studies have been made on lithographic printing plates using a photopolymerization system. In particular, in recent years, a laser printing plate utilizing a high-sensitivity photopolymerization initiation system capable of responding to a visible laser such as an argon laser. Is being developed. Many of these photopolymerizable lithographic printing plate precursors include a compound containing an ethylenic double bond capable of addition polymerization on an aluminum plate as a support, a photopolymerization initiator, an organic polymer binder optionally used, A photopolymerizable composition layer comprising a polymerization inhibitor and the like is provided, and an overcoat layer containing a water-soluble vinyl polymer as a main component is further provided thereon to block oxygen that inhibits polymerization. In these photopolymerizable lithographic printing plate precursors, a relief image is obtained by imagewise exposing a desired image to polymerize and cure an exposed portion and removing an unexposed portion with a developing solution. The unexposed portion exposes the grained aluminum support, and retains water to repel oil-based ink because the surface is hydrophilic. Further, since the portion (image portion) cured by exposure is lipophilic, it repels water and accepts ink. In the method for producing the photopolymerizable lithographic printing plate precursor, a web roll of an aluminum plate having been subjected to necessary surface treatment such as graining is sent out, a photosensitive layer or the like is applied and dried, and the roll is wound as a web roll. The web provided with these necessary layers is continuously cut into a plate of a predetermined size by a roll cutter and is accumulated.

[0003] When the photosensitive lithographic printing plate precursor thus manufactured is printed using a lithographic printing plate prepared by subjecting the photosensitive lithographic printing plate precursor to image exposure and development, non-image portions are liable to have stains and missing image portions. A problem arose. These stains and omissions are caused by scratches on the plate surface that occur when the plates are taken out of a state in which a large number of plates are stacked, such as in the process of accumulating product plates in a production line or during product transportation. These wounds, when winding the web roll after coating the photosensitive layer, on the photosensitive layer, insert and wind a sandwich paper called sandwich paper that has been conventionally sandwiched for each photosensitive lithographic printing original plate, It was found that it could be prevented to some extent by laminating and winding with a plastic film. However, the laser-sensitive high-sensitivity photosensitive layer is soft for accelerating the polymerization reaction, and often has tackiness immediately after coating and drying. In such a case, the inserted interleaf paper adheres to the surface of the photosensitive layer and cannot be peeled off even when the overcoat is applied. The use of a plastic film having a releasable surface solves this problem, but the use of such a special plastic film greatly increases the cost.
In addition, the plate setter requires an interleaf removal mechanism, which requires complicated and expensive equipment, and the interleaf and film are eventually discharged as industrial waste, which is preferable for environmental protection. There are problems such as not.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a process for stacking product plates, transporting a product, or taking out a plate with a plate setter (exposure machine) without using an interleaf paper or a laminating film. Another object of the present invention is to provide a high-sensitivity photosensitive lithographic printing plate which is sensitive to visible laser light and which prevents scratches on the plate surface and does not cause stains on the non-image area or omission of the image area. Another object of the present invention is to provide a photosensitive lithographic printing plate which does not require a slip sheet and can be handled by a plate setter without a slip sheet removing mechanism.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, provided an overcoat layer having a specific coefficient of friction and a back coat layer on the back surface. As a result, the above object has been achieved, and the present invention has been completed. That is, the present invention is a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a surface having an anodized film of an aluminum support having an anodized film on at least one side, and an overcoat layer is provided on the photosensitive layer. Having a backcoat layer on the back surface of the support opposite to the photosensitive layer, wherein the coefficient of friction between the overcoat layer and the backcoat layer is from 0.2 to 0.6. The photosensitive lithographic printing plate described above is provided. The present invention also relates to a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a surface having an anodized film of an aluminum support having an anodized film on at least one side, wherein an overcoat layer is provided on the photosensitive layer. And a back coat layer on the back surface of the support opposite to the photosensitive layer, wherein the overcoat layer contains at least one nonionic surfactant, or the back coat layer contains at least one fatty acid amide. And a photosensitive lithographic printing plate. The photosensitive lithographic printing plate of the present invention is, for example, an aluminum oxide having an anodic oxide film on at least one side, the surface opposite to the surface having the anodic oxide film, after applying a back coat layer, the anodic oxide film After applying a photopolymerizable photosensitive layer on the surface having, and further applying an overcoat layer on the photosensitive layer, winding, and a photosensitive lithographic printing plate web roll,
Thereafter, it can be manufactured by cutting it into a sheet by using a cutting machine.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The photosensitive lithographic printing plate of the present invention and a method for producing the same will be described in detail below. [Coefficient of friction] In the present invention, the coefficient of friction between the overcoat layer and the backcoat layer is from 0.2 to 0.6.
More preferably, it is 0.24 or more and 0.52 or less. The coefficient of friction between the overcoat layer and the backcoat layer is 0.2
If it is less than 1, the surface of the plate is likely to be scratched in a state where a large number of plates are stacked, for example, in a process of accumulating product plates in a production line or during product transportation. If the coefficient of friction between the overcoat layer and the backcoat layer exceeds 0.6, a plate setter (exposure machine)
When the plate is taken out from the state in which a large number of sheets are stacked, scratches are likely to occur on the plate surface. Therefore, in the present invention, all combinations of the components of the overcoat layer and the backcoat layer, the coating amounts, and the like are such that the coefficient of friction between the overcoat layer and the backcoat layer is 0.2 to 0.6. Included in embodiments of the invention.

[Overcoat layer] The photosensitive lithographic printing plate of the present invention has an overcoat layer on a photopolymerizable photosensitive layer (described later) provided on an aluminum support. The overcoat layer is originally provided to prevent polymerization inhibition by oxygen in the air. In the present invention, the overcoat layer is further provided on the back surface of the support opposite to the photosensitive layer. (Described later), and serves to prevent damage to the photosensitive layer surface. As already mentioned,
The components contained in the overcoat layer and the contents thereof can be determined so that the friction coefficient between the overcoat layer and the backcoat layer falls within the range of the present invention, and will be described below with reference to examples.

The overcoat layer of the present invention preferably contains a water-soluble vinyl polymer as a main component. Examples of the water-soluble vinyl polymer include polyvinyl alcohol, a partial ester or ether thereof, and polyvinyl acetal. Other useful polymers include polyvinylpyrrolidone, gelatin and gum arabic, and these may be used alone or in combination. Still further, a copolymer of the above polymer containing an unsubstituted vinyl alcohol unit in an amount substantially necessary for imparting water solubility may be mentioned. As the polyvinyl alcohol, 71 to 1
Those having a hydrolysis degree of 00% and a degree of polymerization in the range of 300 to 2400 are preferred. Specifically, Kuraray's PVA-1
05, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-12
4H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, P
VA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E,
PVA-220E, PVA-224E, PVA-405, PVA-420, PVA-613, L-8 and the like. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate chloroacetate or propionate, polyvinyl formal and polyvinyl acetal, and copolymers thereof.

The overcoat layer of the present invention preferably contains a component for adjusting the coefficient of friction with the backcoat layer. Such components include, for example, surfactants, and nonionic surfactants are particularly preferable. As nonionic surfactants, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, Sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, Polyglycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, Fatty acid diethanol amides,
Nonionic surfactants such as N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, and trialkylamine oxides. Some may be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene, polyoxybutylene, and also include their nonionic surfactants), perfluoroalkylamine oxides, perfluoroalkylethylene oxide additions Product, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, oligomer containing perfluoroalkyl group, hydrophilic group and lipophilic group, containing perfluoroalkyl group and lipophilic group Examples include nonionic fluorine surfactants such as urethane, but are not limited thereto. The above nonionic surfactants may be used alone or
More than one kind can be used in combination, and can be added to the overcoat layer in the range of, for example, 0.01 to 15% by weight, more preferably 0.1 to 10% by weight.

The above-mentioned overcoat layer can be applied by a known application method. For example, US Pat.
458, 311 and JP-A-55-49729. The thickness of the overcoat layer is preferably, for example, in the range of 1 to 10 μm.

[Backcoat layer] On the back side of the support of the photosensitive lithographic printing plate of the present invention, a backcoat layer containing an organic polymer compound is provided. As described above, in the present invention, the coefficient of friction between the overcoat layer and the backcoat layer is desirably 0.2 or more and 0.6 or less. And the amount of application. Therefore, any component can be used in the back coat layer as long as it provides a combination giving such a coefficient of friction. For example, the friction coefficient may be adjusted by adding a lubricant such as a fatty acid amide, a fatty acid, a fatty acid ester, a fatty alcohol, or a silicone oil to a back coat layer made of an organic polymer compound. Among such lubricants, fatty acid amides are particularly preferred. As the fatty acid amide, a saturated or unsaturated carbon number 3 to
30 fatty acid amides. Specific examples include stearic amide, arachidic amide, behenic amide, caproic amide, enantiyl amide, caprylic amide, lauric amide, myristic amide, and palmitic amide. These compounds may be used alone or as a mixture of two or more. The amount of a lubricant such as fatty acid amide added to the backcoat layer may vary depending on the type and amount of the organic polymer compound used in the backcoat layer, the type and amount of the components in the overcoat layer, and the like. As is apparent to those skilled in the art, for example, the content is 0.1 to 10% by weight in the back coat layer. As a main component of the back coat layer of the present invention, for example, at least one resin selected from the group consisting of a saturated copolymerized polyester resin having a glass transition point of 20 ° C. or higher, a phenoxy resin, a polyvinyl acetal resin, and a vinylidene chloride copolymerized resin is used. be able to. The saturated copolymerized polyester resin is composed of a dicarboxylic acid unit and a diol unit. Examples of the dicarboxylic acid unit of the polyester used in the present invention include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, tetrabromophthalic acid, and tetrachlorophthalic acid; adipic acid, azelaic acid, succinic acid, oxalic acid, and suberic acid , Sebacic acid,
Saturated aliphatic dicarboxylic acids such as malonic acid and 1,4-cyclohexanedicarboxylic acid are exemplified.

As the diol unit, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol,
Dipropylene glycol, polypropylene glycol,
1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, hexanediol, 2,2,4-trimethyl-1,
Aliphatic chain diols such as 3-pentanediol; 1,4
And cyclic diols such as -bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecanedimethanol, bisphenoldioxyethylether and bisphenoldioxypropylether. At least one of these dicarboxylic acid and diol units is used, and either one is used as two or more copolymer units. The properties of the copolymer are determined by the copolymer composition and molecular weight. The back coat layer of the present invention is preferably applied by thermocompression bonding of a film or a melt lamination method, but application from a solution is more preferable for providing a thin layer. Accordingly, the copolymerized polyester resin used in the present invention is preferably non-crystalline and easily soluble in various industrial organic solvents.

The molecular weight (average weight) of the saturated copolymerized polyester resin is 10,000 based on the film strength of the back coat layer.
The above is preferred. Further, as a material of the back coat layer in the present invention, a phenoxy resin having a glass transition point of 20 ° C. or higher, a polyvinyl acetal resin, and a vinylidene chloride copolymer resin can be used. The phenoxy resin used in the present invention is manufactured from bisphenol A and epichlorohydrin in the same manner as the epoxy resin, but has excellent chemical resistance and adhesiveness without the use of a curing agent or a catalyst as compared with the epoxy resin, and has a high degree of adhesion. It is suitable as a main component of the coat layer. The polyvinyl acetal resin is a resin obtained by acetalizing polyvinyl alcohol with an aldehyde such as butyl aldehyde or formaldehyde, and a polyvinyl butyral resin or a polyvinyl formal resin is preferably used. These acetal resins have different physical and chemical properties depending on the degree of acetalization, the composition ratio of hydroxyl groups and acetyl groups, and the degree of polymerization. However, the backcoat layer of the present invention has an acetalization degree of 60 mol% or more and an acetyl group of 5 or more. Mol%
Hereinafter, a resin having a polymerization degree of 300 or more is preferably used.

Examples of the vinylidene chloride copolymer resin include copolymers of vinylidene chloride monomer with vinyl monomers such as vinyl chloride, vinyl acetate, ethylene and vinyl methyl ether, and acrylic monomers such as (meth) acrylate and (meth) acrylonitrile. A polymer resin is used.
Above all, a vinylidene chloride copolymer containing acrylonitrile in a range of 20 mol% or less is preferable because it has high solubility in general-purpose organic solvents. The glass transition point of the resin used in the back coat layer of the present invention is 20 ° C. or higher, more preferably 30 ° C. or higher, and it is desirable to use a resin insoluble in water and an alkaline developer having a pH of 8.5 or higher. A resin having a glass transition point of less than 20 ° C. is not preferable because it adheres to the photosensitive layer. Other hydrophobic polymer compounds are optionally added to the back coat layer of the present invention. Examples of such hydrophobic polymer compounds include polybutene, polybutadiene, polyamide, unsaturated copolymerized polyester resin, polyurethane, polyurea, polyimide, polysiloxane, polycarbonate, epoxy resin, chlorinated polyethylene, aldehyde condensation resin of alkylphenol, polyvinyl chloride, and polyvinyl chloride. Polyvinylidene chloride, polystyrene, acrylic resins and their copolymer resins, hydroxycellulose,
Polyvinyl alcohol, cellulose acetate, carboxymethyl cellulose and the like are suitable.

Other suitable hydrophobic polymer compounds include copolymers having a molecular weight (weight average) of usually 10,000 to 200,000, containing the monomers shown in the following (1) to (12) as constituent units. Can be. (1) Acrylamides, methacrylamide acids, acrylates, methacrylates and hydroxystyrenes having an aromatic hydroxyl group, for example, N- (4
-Hydroxyphenyl) acrylamide or N- (4
-Hydroxyphenyl) methacrylamide, o-, m-
And p-hydroxystyrene, o-, m- and p-
Hydroxyphenyl acrylate or methacrylate, (2) acrylates and methacrylates having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) methyl acrylate, ethyl acrylate, acryl Propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N- (Substituted) acrylates such as dimethylaminoethyl acrylate,

(4) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
Amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid
(Substituted) methacrylates such as 2-chloroethyl, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, (5) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N- Ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, N-phenyl acrylamide, N -Phenylmethacrylamide, N-benzylacrylamide,
N-benzyl methacrylamide, N-nitrophenyl acrylamide, N-nitrophenyl methacrylamide,
Acrylamide or methacrylamide such as N-ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide;

(6) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and phenyl vinyl ether; (7) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate; (8) styrenes such as styrene, methyl styrene and chloromethyl styrene; 9) vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone;
(10) olefins such as ethylene, propylene, isobutylene, butadiene, isoprene, (11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc.

(12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) Naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Phenyl)
Methacrylamides such as methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, and o-aminosulfonylphenyl acrylate and m-aminosulfonylphenyl Acrylate, p-
Unsaturated sulfonamides such as acrylates such as aminosulfonylphenyl acrylate and 1- (3-aminosulfonylphenylnaphthyl) acrylate, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate; Unsaturated sulfonamides such as methacrylic esters such as 1- (3-aminosulfonylphenylnaphthyl) methacrylate;

Further, a monomer copolymerizable with the above monomer may be copolymerized. In addition, a copolymer obtained by copolymerization of the above-mentioned monomers, for example, modified with glycidyl acrylate, glycidyl methacrylate or the like is also included, but is not limited thereto. These hydrophobic polymer compounds can be added to the back coat layer in a range of 50% by weight or less. However, in order to make use of the properties of saturated copolymerized polyester resin, phenoxy resin, polyvinyl acetal resin and vinylidene chloride copolymerized resin, 30% by weight is required. It is preferable that the content be not more than weight%.

In addition to these hydrophobic polymer compounds, a plasticizer, a surfactant and other additives can be added to the back coat layer for the purpose of imparting flexibility and adjusting the slipperiness. . Preferred plasticizers include, for example,
Phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate and diallyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethyl Glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, glycol esters such as triethylene glycol dicaprylate, phosphates such as tricresyl phosphate, triphenyl phosphate, diisobutyl adipate, dioctyl Adipate, dimethyl sebacate, dibutyl sebacate, dioctyl azelate, Aliphatic dibasic acid esters such as butyl maleate, polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate is effective.

The plasticizer is preferably added within a range where the glass transition point of the entire backcoat layer is not lower than 20 ° C., and is generally about 30% by weight or less based on the resin used for the backcoat layer. It is desirable that a surfactant is further added to the back coat layer of the present invention for the purpose of improving the slip property, the coated surface state, the adhesion to the support, and the like. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants.

Preferred examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and glycerin fatty acid partial esters. , Sorbitan fatty acid partial esters,
Pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters , Polyoxyethylenated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides,
N, N-bis-2-hydroxyalkylamines, nonionic surfactants such as polyoxyethylene alkylamine, triethanolamine fatty acid ester, and trialkylamine oxide, fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, Alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates,
Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated tallow oil , Fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl Phosphate salts, polyoxyethylene alkyl ether phosphate salts, polyoxyethylene alkyl phenyl ether phosphate salts, Anionic surfactants such as partially saponified products of tylene / maleic anhydride copolymer, partially saponified products of olefin / maleic anhydride copolymer, condensates of naphthalenesulfonate and formalin, alkylamine salts, quaternary Cationic surfactants such as ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives; amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imitazolines.
Among the surfactants mentioned above, those with polyoxyethylene are polyoxymethylene, polyoxypropylene,
It can be read as a polyoxyalkylene such as polyoxybutylene, and those surfactants are also included.

Further preferred surfactants are fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of the fluorine-based surfactant include an anionic type such as perfluoroalkyl carboxylate, perfluoroalkyl sulfonate, and perfluoroalkyl phosphate, an amphoteric type such as perfluoroalkyl betaine, and a perfluoroalkyltrimethylammonium salt. Cationic and perfluoroalkylamine oxides, perfluoroalkylethylene oxide adducts, oligomers containing perfluoroalkyl groups and hydrophilic groups, oligomers containing perfluoroalkyl groups and lipophilic groups, perfluoroalkyl groups, hydrophilic groups and lipophilic Non-ionic types such as a group-containing oligomer, a perfluoroalkyl group and a lipophilic group-containing urethane are included. The above surfactants can be used alone or in combination of two or more, and 0.001 to 10% by weight in the back coat layer.
More preferably, it is added in the range of 0.01 to 5% by weight. The back coat layer of the present invention further comprises a dye or pigment for coloring, a silane coupling agent for improving adhesion to an aluminum support, a diazo resin comprising a diazonium salt, an organic phosphonic acid, an organic phosphoric acid and a cationic compound. Wax, which is usually used as a slip agent, such as a polymer,
Higher fatty acids, higher fatty acid amides, silicone compounds composed of dimethylsiloxane, modified dimethylsiloxane, polyethylene powder and the like are appropriately added.

The thickness of the back coat layer of the present invention is 0.1 to 0.1.
A range of 8 μm is preferred. (If the thickness is less than 0.1 μm, it is not possible to prevent the photosensitive layer from being scratched when the photosensitive lithographic printing plates are handled in an overlapping manner.) The thickness fluctuates due to the dissolution or swelling of the coat layer, the printing pressure changes, and the printing characteristics deteriorate. Various methods can be applied to coat the back coat layer on the back surface of the aluminum support. For example, a solution in an appropriate solvent, or a method of coating and drying as an emulsified dispersion, for example, a method in which a preformed film is bonded to an aluminum support with an adhesive or heat and a melt extruder to form a molten film. A method of forming and bonding the mixture to a support may be mentioned, but the most preferable method for securing the above-mentioned coating amount is a method of applying a solution and drying. As the solvent used here, an organic solvent described in JP-A-62-251739 may be used alone or as a mixture.

As a method of applying such a coating liquid, a known metering coating apparatus such as a bar coater, a roll coater, a gravure coater, a curtain coater, an extruder, a slide hopper, etc. can be used. A non-contact quantitative coater such as a curtain coater, an extruder, and a slide hopper is particularly preferable from the viewpoint of not damaging it.

[Support] The support used in the photosensitive lithographic printing plate of the present invention is a plate made of aluminum and an aluminum alloy. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of a different element. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is preferably at most 10% by weight or less. Aluminum suitable for the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and a conventionally known and used material such as JIS A1050,
JIS A1100, JIS A3003, JIS A3
103, JIS A3005, etc. can be used as appropriate. The thickness of the aluminum plate used in the present invention,
Usually, it is about 0.1 mm to 0.6 mm.

Prior to roughening the aluminum plate, if necessary, a degreasing treatment with, for example, a surfactant, an organic solvent or an alkaline aqueous solution is performed to remove the rolling oil on the surface. First, the surface of an aluminum plate is subjected to a surface roughening treatment, which includes a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of selectively dissolving the surface chemically. There is a way. As the mechanical method, a known method called a ball polishing method, a brush polishing method, a blast polishing method, a buff polishing method, or the like can be used. Further, as an electrochemical surface roughening method, there is a method of performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both the mechanical surface roughening method and the electrochemical surface roughening method are combined can be used. The aluminum plate thus roughened is subjected to an alkali etching treatment and a neutralization treatment as required, and then subjected to an anodic oxidation treatment in order to increase the water retention and abrasion resistance of the surface.
As the electrolyte used for the anodic oxidation treatment of the aluminum plate, any electrolyte that forms a porous oxide film can be used, and generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.

The anodic oxidation treatment conditions vary depending on the electrolyte used and cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° C., and the current density is 5 to 70%. It is appropriate that the voltage is 60 A / dm ² , the voltage is 1 to 100 V, and the electrolysis time is 10 seconds to 5 minutes. Among them, a method in which sulfuric acid is used as an electrolyte and anodization is performed at a high current density as described in British Patent No. 1,412,768 and US Pat. No. 4,211,619 are described. Anodization is preferably performed in an aqueous solution of sulfuric acid having such a low concentration. The concentration of sulfuric acid is 5 to 20% by weight, the concentration of dissolved aluminum ions is 3 to 15% by weight, and the temperature is 25 to 50 ° C. Most preferred is a method of anodizing with direct current at a current density of 20 A / dm ² . 1.0 g of anodized film
/ M ² or more is preferred, but more preferably 2.0 to 6.0.
g / m ² . When the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient, and the non-image area of the lithographic printing plate is easily damaged, and the ink adheres to the damaged area during printing, so-called “ink”. "Scratch dirt" easily occurs.

After the anodic oxidation treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. U.S. Pat. No. 2,714,066 discloses a hydrophilic treatment used in the present invention.
No. 3,181,461, 3,280,734 and No.
There is an alkali metal silicate (for example, sodium silicate aqueous solution) method as disclosed in US Pat. No. 3,902,734. In this method, the support is immersed or electrolytically treated in an aqueous solution of sodium silicate. In addition, potassium fluoride zirconate disclosed in JP-B-36-22063 and U.S. Pat. No. 3,276,868.
No. 4,153,461 and 4,689,272, a method of treating with polyvinyl phosphonic acid or the like is used.

[Photopolymerizable photosensitive layer] As described above, a known photopolymerizable photosensitive layer is formed on an aluminum plate having a hydrophilic surface optionally subjected to a surface roughening treatment, an anodic oxidation treatment and, if necessary, a hydrophilic treatment. A photosensitive layer made of a hydrophilic composition is provided. The main components of the photopolymerizable composition are a compound containing an addition-polymerizable ethylenic double bond, a photopolymerization initiator, an organic polymer binder, a thermal polymerization inhibitor, and the like. Various compounds such as plasticizers are added. The compound containing an addition-polymerizable double bond can be arbitrarily selected from compounds having at least one, and preferably two or more, terminal ethylenically unsaturated bonds. For example, it has a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof. Examples of monomers and copolymers thereof include esters of unsaturated carboxylic acids (eg, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) with aliphatic polyhydric alcohol compounds, and unsaturated esters. An amide of a carboxylic acid and an aliphatic polyamine compound is exemplified.

Specific examples of the ester monomer of the aliphatic polyhydric alcohol compound and the unsaturated carboxylic acid include acrylates such as ethylene glycol diacrylate, triethylene glycol diacrylate, and 1,3.
-Butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate , Sol Bitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer and the like.

Examples of the methacrylate include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol. Dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3- Methacryloxy-2-hydride Roxypropoxy) phenyl] dimethylmethane, bis [p- (methacryloxyethoxy)
Phenyl] dimethylmethane. Examples of itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, and pentaerythritol diitaconate. And sorbitol tetritaconate.

The crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Sorbitol tetracrotonate and the like. As isocrotonic acid esters, ethylene glycol diisocrotonate, pentaerythritol diisocrotonate,
And sorbitol tetraisocrotonate. The maleic acid ester includes ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, sorbitol tetramaleate and the like. Furthermore, a mixture of the above-mentioned ester monomers can also be mentioned.

Specific examples of the amide monomer of the aliphatic polyamine compound and the unsaturated carboxylic acid include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriaminetrisacrylamide, xylylenebisacrylamide, xylylenebismethacrylamide, and the like. Another example is JP-B-48-417.
JP-A-08-0838, in which a hydroxyl-containing vinyl monomer represented by the following general formula (A) is added to a polyisocyanate compound having two or more isocyanate groups in one molecule. And vinyl urethane compounds containing at least two polymerizable vinyl groups. CH ₂ ＣC (R) COOCH ₂ CH (R ′) OH (A) (where R and R ′ represent H or CH ₃ )

Also, urethane acrylates described in JP-A-51-37193,
64183, JP-B-49-43191, JP-B-52
And polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid as described in JP-A-30490. Furthermore, Japan Adhesion Association Journal vol.20, No.7, 300-3
Those introduced as photocurable monomers and oligomers on page 08 (1984) can also be used. In addition, the amount of these used is 5-7 with respect to all the components.
0% by weight (hereinafter abbreviated as%), preferably 10 to 5%
0%. As the photopolymerization initiator, depending on the wavelength of the light source used, patents, various photoinitiators known in the literature, etc.
Alternatively, a combination system (photoinitiating system) of two or more photoinitiators can be appropriately selected and used. For example, when ultraviolet light of 400 nm or less is used as a light source, benzyl, benzoin ether, Michler's ketone, anthraquinone, acridine, phenazine, benzophenone, and the like are widely used.

Further, in a more preferred embodiment of the present invention, a visible light of 400 nm or more, an argon laser, YA
When a G-SHG laser is used as a light source, various photo initiation systems have been proposed. For example, US Pat. No. 2,850,44.
Certain photosensitive dyes described in No. 5, a compound-initiating system of a dye and an amine (Japanese Patent Publication No. 44-20189), and a combination system of hexaarylbiimidazole, a radical generator and a dye (Japanese Patent Publication No. 45-37377) Of hexaarylbiimidazole and p-dialkylaminobenzylidene ketone (JP-B-47-2528, JP-A-54-155292)
), A system of a cyclic cis-α-dicarbonyl compound and a dye (JP-A-48-84183), a system of a substituted triazine and a merocyanine dye (JP-A-54-151024),
A system of ketocoumarin and an activator (JP-A-52-11268)
No. 1, JP-A-58-15503), biimidazole,
Styrene derivative, thiol system (JP-A-59-1402)
No. 03), a system of an organic peroxide and a dye (JP-A-59-14)
No. 0203, JP-A-59-189340), a system of a dye having a rhodanine skeleton and a radical generator (JP-A-2-244)
No. 050), a system of titanocene and a 3-ketocoumarin dye (JP-A-63-221110), a system of a combination of titanocene and a xanthene dye, and an addition-polymerizable ethylenically unsaturated compound containing an amino group or a urethane group (JP-A-Hei. JP-A-4-221958, JP-A-4-219756
No.) and a system of titanocene and a specific merocyanine dye (JP-A-6-295061).

The amount of the photopolymerization initiator used is 0.05 to 100 parts by weight based on 100 parts by weight of the ethylenically unsaturated compound.
It can be used in an amount of preferably 0.1 to 70 parts by weight, more preferably 0.2 to 50 parts by weight. The photopolymerizable composition usually contains a linear organic polymer conjugate as a binder, and such a linear organic polymer conjugate has compatibility with a photopolymerizable ethylenically unsaturated compound. Any one may be used as long as it has a linear organic high molecular polymer. Preferably, a water-soluble or weakly alkaline water-soluble or swellable linear organic high molecular polymer that enables water development or weakly alkaline water development is selected. The linear organic high molecular polymer is selected and used not only as a film-forming agent of the composition but also as a developer for water, weakly alkaline water, or an organic solvent. For example,
Use of a water-soluble organic high molecular polymer enables water development. Examples of such a linear organic high molecular weight polymer include an addition polymer having a carboxylic acid group in a side chain, for example, JP-A-59-4
4615, JP-B-54-34327, JP-B-58-
12577, JP-B-54-25957, JP-A-54
-92723, JP-A-59-53836 and JP-A-5-53836.
No. 9-71048, namely, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer,
There are partially esterified maleic acid copolymers and the like. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in the side chain. In addition, those obtained by adding a cyclic acid anhydride to an addition polymer having a hydroxyl group are useful. In particular, among these, [benzyl (meth) acrylate / (meth) acrylic acid / optionally other addition-polymerizable vinyl monomers] copolymer and [allyl (meth) acrylate / (meth) acrylic acid / optionally And other addition-polymerizable vinyl monomers] copolymers. In addition, polyvinyl pyrrolidone, polyethylene oxide, and the like are useful as the water-soluble linear organic polymer. In order to increase the strength of the cured film, alcohol-soluble nylon or 2,2-bis- (4
-Hydroxyphenyl) -propane and epichlorohydrin polyether are also useful. These linear organic high molecular polymers can be mixed in an arbitrary amount in the whole composition. However, if it exceeds 90% by weight, no favorable result is obtained in view of the strength of the formed image and the like. Preferably 3
0 to 85%. Further, the weight ratio of the photopolymerizable ethylenically unsaturated compound and the linear organic high molecular weight polymer is 1/9 to 7
/ 3 is preferable. A more preferred range is 2
/ 8 to 6/4.

In the present invention, in addition to the above basic components, a small amount of thermal polymerization inhibitor is used to prevent unnecessary thermal polymerization of a polymerizable ethylenically unsaturated compound during the production or storage of the photosensitive composition. It is desirable to add an agent. Suitable thermal polymerization inhibitors include hydroquinone, p-
Methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl −
6-t-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like. The addition amount of the thermal polymerization inhibitor is about 0.01 based on the weight of the whole composition.
% To about 5% is preferred. Further, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition by oxygen, and may be unevenly distributed on the surface of the photosensitive layer in a drying process after coating. . The addition amount of the higher fatty acid derivative is preferably about 0.5% to about 10% of the whole composition. Further, a coloring agent may be added for the purpose of coloring the photosensitive layer. Examples of the coloring agent include phthalocyanine pigments, azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, azo dyes, anthraquinone pigments, and cyanine dyes. The amount of dye and pigment added is about 0.5 of the total composition.
% To about 5% is preferred. In addition, additives such as inorganic fillers and plasticizers such as dioctyl phthalate, dimethyl phthalate and tricresyl phosphate may be added to improve the physical properties of the cured film. The amount of these additives is preferably 10% or less of the total composition.

In the present invention, the photopolymerizable composition is dissolved in various organic solvents and coated on a support to form a photopolymerizable photosensitive layer. The solvent used here is acetone,
Methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichloride, tetrahydrofuran, toluene,
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl Ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether,
Propylene glycol monomethyl ether acetate,
Propylene glycol monoethyl ether acetate,
3-methoxypropyl acetate, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate and the like. These solvents can be used alone or as a mixture. The appropriate concentration of the solid content in the coating solution is 2 to 50% by weight.

The amount of coating is about 0.1 g / m 2 after drying.
The range of ² to about 10 g / m ² are suitable. More preferably, it is 0.5 to 5 g / m ² . As the coating amount increases, the exposure amount is required, but the photosensitive film becomes stronger, for example,
When used as a printing plate, a printing plate with a high printable number (high printing durability) is obtained. In the photosensitive composition of the present invention, a surfactant for improving the coated surface quality can be added. Preferred examples of the surfactant include all the surfactants exemplified as the surfactant used in the back coat layer. An overcoat layer is provided on the photosensitive layer thus coated as described above.

[Development treatment] The photosensitive lithographic printing plate thus obtained is passed through a transparent original image using a carbon arc lamp, a mercury lamp,
Exposure to active light from a metal halide lamp, xenon lamp, tungsten lamp, etc.
After being directly exposed by an Ar laser and a YAG-SHG laser, it is developed. As a developing solution used for such a developing process, a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium, tribasic sodium, potassium, ammonium, dibasic sodium, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, potassium Inorganic alkali agents such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine,
Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used. These alkali agents are used alone or in combination of two or more.

Among the above-mentioned alkaline aqueous solutions, the developing solution in which the effect of the present invention is further exhibited is an aqueous solution containing an alkali metal silicate and having a pH of 12 or more. The aqueous solution of the alkali metal silicate is composed of silicon oxide S which is a component of the silicate.
The ratio of iO ₂ and alkali metal oxide M ₂ O (generally [Si
O ₂ ] / [M ₂ O], where [SiO ₂ ] is Si
O ₂ molar concentration (mol / l), [M ₂ O] indicates the molar concentration (mol / l) of alkali metal M oxide M ₂ O)
And the density can be adjusted according to the density. For example, as disclosed in JP-A-54-62004,
When the molar ratio of SiO ₂ / Na ₂ O is 1.0 to 1.5 (that is, [Si
O ₂ ] / [Na ₂ O] is 1.0 to 1.5) and SiO 2
₂ in an aqueous solution of sodium silicate having a content of 1 to 4% by weight, or as described in JP-B-57-7427, when [SiO ₂ ] / [M] is 0.5 to 0.75 ( That is, [S
iO ₂ ] / [M ₂ O] is 1.0 to 1.5) and SiO 2
_An alkali metal silicate comprising a concentration of 1 to 4% by weight of ₂ and the developer contains at least 20% potassium, based on gram atoms of the total alkali metal present therein. Is preferably used.

Further, when developing the photosensitive lithographic printing plate using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developing solution is added to the developing solution.
It is known that a large amount of photosensitive lithographic printing plates can be processed without replacing the developing solution in the developing tank for a long time. This replenishment system is also preferably applied in the present invention. For example, as disclosed in JP-A-54-62004, the molar ratio of SiO ₂ / Na ₂ O in the developer is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O]. 1.0
To 1.5), wherein an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4% by weight is used, and continuously or intermittently depending on the throughput of the positive photosensitive lithographic printing plate. S
When the molar ratio of iO ₂ / Na ₂ O is 0.5 to 1.5 (ie [SiO 2
₂ ] / [Na ₂ O] of 0.5 to 1.5), a method of adding an aqueous solution of sodium silicate (replenisher) to the developer, and further disclosed in JP-B-57-7427. Si
O ₂ ] / [M] is 0.5 to 0.75 (that is, [SiO ₂ ] /
An alkali metal silicate used as a replenisher using a developer of an alkali metal silicate in which [M ₂ O] is 1.0 to 1.5) and a concentration of SiO ₂ is 1 to 4% by weight [Si
O ₂ ] / [M] is 0.25 to 0.75 (that is, [SiO ₂ ]
/ [M ₂ O] is 0.5 to 1.5), and at least 20% potassium based on the total alkali metal gram atoms both are present therein of the developing solution and the replenisher Is preferably used.

When an alkali metal silicate is used as such a replenisher, its molar ratio [SiO ₂ ] / [M ₂ O]
By reducing the value of, the replenisher becomes highly active and the amount of replenishment can be reduced, so that the running cost and the amount of waste liquid are reduced, which is preferable. However, it is known that the aluminum of the support of the photosensitive lithographic printing plate dissolves with the activation, and insoluble matter is generated in the developer. Since the back coat layer of the photosensitive lithographic printing plate of the present invention can also suppress the elution of aluminum from the back surface of the support, the lithographic printing plate can be preferably processed even in a high-activity development replenishment system. Such a highly active developer has a SiO ₂ / M ₂ O molar ratio of 0.7.
１1.5, and the concentration of SiO ₂ is 1.0-4.0% by weight.
And an aqueous solution of an alkali metal silicate.
A particularly preferred replenisher has a SiO ₂ / M ₂ O molar ratio of 0.3 to 1.0, and a SiO ₂ concentration of 0.3 to 4.0.
It is an aqueous solution of alkali metal silicate by weight. More preferably the molar ratio is 0.3 to 0.6, SiO ₂ concentration is 0.5 to 2.0 wt%. When the SiO ₂ / M ₂ O molar ratio of the replenisher is smaller than 0.3, the dissolution of the anodic oxide film in the non-image area (the area where the photosensitive layer is removed by development) on the side of the aluminum support having the photosensitive layer is reduced. It becomes too large to suppress the generation of insolubles. On the other hand, when the molar ratio is 1.0 or more, the activity of the replenisher is inferior, so that a large amount of replenishment is required, which is not suitable for the purpose of the present invention. In addition, Si
When the O ₂ concentration is less than 0.5% by weight, insolubles are easily formed,
If the content is more than 4.0% by weight, a large amount of silica gel is generated during the neutralization treatment of the used waste liquid, which is not preferable.

The developing solution and replenisher used for developing the photosensitive lithographic printing plate of the present invention are required for the purpose of promoting or suppressing the developing property, dispersing the developing residue, and enhancing the ink affinity of the printing plate image area. Various surfactants and organic solvents can be added accordingly. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Preferred examples of the surfactant include all the surfactants exemplified as the surfactant used in the back coat layer, and the organic boron surfactant described in Japanese Patent Publication No. 1-57895 is particularly preferable. preferable. The above surfactants can be used alone or in combination of two or more, and are added to the developer in an amount of 0.001 to 10% by weight, more preferably 0.01 to 5% by weight. Suitable organic solvents are those having a solubility in water of about 10% by weight or less, preferably 5% by weight or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1
-Propanol, 4-phenyl-1-butanol, 4-
Phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol,
-Methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol, N-phenylethanolamine, N-phenyldiethanolamine and the like can be mentioned. The content of the organic solvent is 0.1 to 5% by weight based on the total weight of the used solution. The amount used is closely related to the amount used of the surfactant, and it is preferable to increase the amount of the surfactant as the amount of the organic solvent increases. This is because when the amount of the surfactant is small and the amount of the organic solvent is large, the organic solvent is not completely dissolved, and therefore, it is impossible to expect good developing property.

In the present invention, a reducing agent is further added to a developer and a replenisher used for developing a photosensitive lithographic printing plate. This prevents contamination of the printing plate, and is particularly effective when developing a negative photosensitive lithographic printing plate containing a photosensitive diazonium salt compound. Preferred organic reducing agents include thiosalicylic acid, hydroquinone, metol,
Examples include phenol compounds such as methoxyquinone, resorcin and 2-methylresorcin, and amine compounds such as phenylenediamine and phenylhydrazine. Further preferred inorganic reducing agents include sodium salts, potassium salts, and ammonium salts of inorganic acids such as sulfurous acid, bisulfite, phosphorous acid, bisulfite, diphosphite, thiosulfate and dithionite. Salts and the like can be mentioned. Among these reducing agents, sulfites are particularly excellent in the stain prevention effect. These reducing agents are preferably contained in a range of 0.05 to 5% by weight based on the developer used.
An organic carboxylic acid can be further added to the developer and the replenisher. Preferred organic carboxylic acids have 6 to 6 carbon atoms.
20 aliphatic carboxylic acids and aromatic carboxylic acids. Specific examples of the aliphatic carboxylic acid include caproic acid, enantiic acid, caprylic acid, lauric acid, myristic acid, palmitic acid and stearic acid, and particularly preferred are alkanoic acids having 8 to 12 carbon atoms. . Further, unsaturated fatty acids having a double bond in the carbon chain or branched fatty acids may be used.

The aromatic carboxylic acid is a compound in which a carboxyl group is substituted on a benzene ring, a naphthalene ring, an anthracene ring, or the like. Specifically, o-chlorobenzoic acid,
p-chlorobenzoic acid, o-hydroxybenzoic acid, p-hydroxybenzoic acid, o-aminobenzoic acid, p-aminobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6- Dihydroxybenzoic acid, 2,3
-Dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid, 1-hydroxy-2-nastoic acid, 3-
There are hydroxy-2-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-naphthoic acid, 2-naphthoic acid and the like, and hydroxynaphthoic acid is particularly effective. The above aliphatic and aromatic carboxylic acids are preferably used as sodium salts, potassium salts or ammonium salts in order to increase the water solubility. The content of the organic carboxylic acid in the developer used in the present invention is not particularly limited, but if it is less than 0.1% by weight, the effect is not sufficient, and if it is 10% by weight or more, the effect can be further improved. Not only, it can hinder dissolution when another additive is used in combination. Therefore, the preferred addition amount is 0.1 to 10% by weight, more preferably 0.5 to 4% by weight, based on the developer used. The developer and the replenisher may further contain conventionally known compounds such as an antifoaming agent and a water softener, if necessary.

Examples of the water softener include polyphosphoric acid and its sodium, potassium and ammonium salts, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2- Aminopolycarboxylic acids such as diaminocyclohexanetetraacetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium salts,
Potassium and ammonium salts, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid), hydroxyethylethylenediaminetri (methylenephosphonic acid) and 1 -Hydroxyethane-
1,1-diphosphonic acids and their sodium, potassium and ammonium salts. The optimum value of such a water softener varies depending on the chelating power, the hardness of the hard water used and the amount of the hard water.
It is in the range of 1 to 5% by weight, more preferably 0.01 to 0.5% by weight. If the added amount is less than this range, the intended purpose is not sufficiently achieved, and if the added amount is more than this range, adverse effects on the image area such as color omission appear. The remaining component of the developer and replenisher is water, but may optionally contain various additives known in the art.

It is advantageous from the viewpoint of transportation that the developing solution and the replenisher are prepared as concentrated solutions having a smaller water content than at the time of use, and are diluted with water at the time of use. The degree of concentration in this case is suitably such that each component does not cause separation or precipitation. In the developing method of the present invention, the components in the developer consumed by processing the plate, the developer adhered to the processed plate and / or neutralized by carbon dioxide in the air are used. A replenisher is added in such an amount as to compensate for the alkali component in the developer. For example, when developing with an automatic developing machine that processes a plate while transporting it with rollers, as described in British Patent No. 2046931, an amount of replenishment is proportional to the length of the plate to be processed in the transport direction. A method of adding a solution, a method of adding a replenisher in an amount proportional to the area of the plate to be processed, or a replenisher in an amount proportional to a time in which a developer circulation pump of an automatic developing machine is operated together with these additions. A method in which the liquid is added intermittently is advantageous. Further, as described in U.S. Pat. No. 4,882,246 and European Patent No. 107454, a method of measuring the electric conductivity or impedance of a developer and adding a replenisher according to the measured value is also preferable. Is the way.

Regardless of the means by which the replenisher is added, it has been developed and / or developed to compensate for changes in the components of the developer by developing the photosensitive lithographic printing plate and / or over time. A replenisher is added to make up for the amount of developer taken out with the photosensitive lithographic printing plate. The photosensitive lithographic printing plate thus developed is described in JP-A-54-8002, JP-A-55-115045,
As described in JP-A-59-58431 and the like, post-treatment is carried out with washing water, a rinsing solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. For the post-processing of the photosensitive lithographic printing plate of the present invention, these processings can be used in various combinations. In recent years, in the plate making and printing industry, to streamline and standardize plate making work,
Automatic developing machines for photosensitive lithographic printing plates are widely used. This automatic developing machine generally comprises a developing section and a post-processing section, and comprises a device for transporting a photosensitive lithographic printing plate, each processing solution tank and a spray device, and horizontally transports an exposed photosensitive lithographic printing plate. The developing solution is sprayed from a spray nozzle on each processing solution pumped up by a pump. Recently, a method has been known in which a photosensitive lithographic printing plate is immersed and conveyed in a processing liquid tank filled with a processing liquid by a submerged guide roll or the like for processing. And an automatic developing machine as described in JP-A-2-32357. In such an automatic processing, the processing can be performed while replenishing each processing liquid with a replenisher according to the processing amount, the operating time, and the like. Further, a so-called disposable processing method in which processing is performed with a substantially unused processing liquid can also be applied. The lithographic printing plate obtained by such a process is set on an offset printing machine and used for printing a large number of sheets.

[0051]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples. Example 1 An aluminum plate having a thickness of 0.24 mm was grained with a nylon brush and an aqueous suspension of pumicestone of 400 mesh, and then washed thoroughly with water. 10
After being immersed in a 70% aqueous sodium hydroxide solution at 70 ° C. for 60 seconds for etching, the film was washed with running water, neutralized with a 20% aqueous HNO ₃ solution, and washed with water. This was subjected to electrolytic surface roughening treatment in a 1% nitric acid aqueous solution at an anode-time electricity quantity of 160 coulomb / dm ² using a sine wave alternating current under the condition of VA = 12.7V. When the surface roughness was measured, it was 0.6 μm.
(Ra display). After immersion in a 30% aqueous solution of H ₂ SO _{4 and} desmutting at 55 ° C. for 2 minutes,
In a 0% H ₂ SO ₄ aqueous solution, a cathode was placed on the grained surface, and anodized so that the thickness became 2.7 g / m ² at a current density of 2 A / dm ² , thereby producing a substrate-1. did. At this time, the anodic oxide film on the back surface was about 0.2 g / m ² at the center of the aluminum plate and about 0.5 g / m ² at the end.

A back coat layer, a photosensitive layer, and an overcoat layer were sequentially applied to the substrate 1, dried, and wound up as a web roll. This web roll was cut into a sheet by a roll cutter to obtain a lithographic printing plate.
Further details are described below. A back coat layer coating solution B (I) comprising the following components was applied to the back surface of the substrate-1 using a wire bar coater so that the thickness after drying was 1 μm, and dried at 80 ° C. for 2 minutes. did.

Backcoat layer coating solution B (I) Saturated copolyester resin 3.0 parts by weight (terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol = 1: 1: 1: 1, molecular weight 18,000, glass (Transition point 67 ° C) Methyl ethyl ketone 100 parts by weight Megafac F-177 0.05 parts by weight (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) The following photosensitive layer coating solution was applied by an extruder so that the coated amount after drying was 1.5 g / m ^2, and dried at 100 ° C. for 2 minutes.

Photosensitive solution A Pentaerythritol tetraacrylate 1.5 g Benzyl methacrylate / methacrylic acid (80/20 molar ratio) copolymer, molecular weight 30,000 (A) 2.0 g Compound represented by the following formula (1) 0.15 g Compound represented by the following formula (2) 0.20 g Compound represented by the following formula (3) 0.4 g ε-phthalocyanine / (A) dispersion 0.2 g Megafac F-177 (Dainippon Ink & Chemicals, Inc.) 0.02 g Propylene glycol monomethyl ether 7.5 g Methyl ethyl ketone 9.0 g Toluene 11.0 g

[0055]

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The following overcoat layer was coated on the aluminum photosensitive layer provided with the back coat layer (the one using the back coat layer coating solution B (I)) and the photosensitive layer (the one coated with the photosensitive solution A). Extruder application of liquid O-1
Dry at 120 ° C. for 2 minutes. At this time, the dry coating weight of the overcoat layer was 2.5 g / m ² . Overcoat layer coating solution O-1 Polyvinyl alcohol (degree of saponification: 90 mol%, degree of polymerization: 1000) 5 parts by weight EMALEX NP-10 0.05 parts by weight (Nonionic surfactant manufactured by Nippon Emulsion Co., Ltd.) Water 95 parts by weight The lithographic printing plate thus prepared was used as a sample a, and the friction coefficient between the overcoat layer and the backcoat layer was measured by a friction coefficient measuring device manufactured by Toyo Seiki Co., Ltd. (Table 1). The procedure for measuring the coefficient of friction is as follows. The sample (1) is fixed on a flat surface with the overcoat layer facing upward. On top of this, the sample (2) was 65 mm ×
Cut into 110 mm rectangles and layer. At this time, the back coat layer of the sample (2) and the overcoat layer of the sample (1) face each other. The size of sample (1) is the size of sample (2) (65 mm ×
(A rectangle of 110 mm).
A load of 1000 g is placed on the sample (2), the sample plane is inclined at a constant speed (2.7 degrees / second), and the inclination angle (θ) at which the sample (2) starts moving (sliding). ) Is measured. The coefficient of friction is calculated as tan (θ).

[Examples 2 and 3] In Example 1, the overcoat layer was provided by using the following coating solutions O-2 and O-3 instead of the overcoat layer coating solution O-1. The friction coefficient was measured in the same manner as Samples b and c, respectively (Table 1). Overcoat layer coating solution O-2 Polyvinyl alcohol (degree of saponification 90 mol%, degree of polymerization 1000) 5 parts by weight EMALEX NP-10 0.1 part by weight (Nonionic surfactant manufactured by Nippon Emulsion Co., Ltd.) Water 95 parts by weight Overcoat layer coating liquid O-3 Polyvinyl alcohol (degree of saponification 90 mol%, degree of polymerization 1000) 5 parts by weight EMALEX NP-10 0.2 parts by weight (Nonionic surfactant manufactured by Nippon Emulsion Co., Ltd.) Water 95 parts by weight

Example 4 Backcoat layer coating solution B (I)
In the same manner as in Example 1 except that the following back coat layer coating solution B (I) -1 was used instead of and the following overcoat layer coating solution O was used instead of the overcoat layer coating solution O-1 To prepare a lithographic printing plate. With the lithographic printing plate thus prepared as d, the coefficient of friction between the overcoat layer and the backcoat layer was measured (Table 1). Backcoat layer coating solution B (I) -1 Saturated copolyester resin 3.0 parts by weight (terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol = 1: 1: 1: 1, molecular weight 18,000, glass transition) (Point 67 ° C.) Methyl ethyl ketone 100 parts by weight Megafac F-177 0.05 parts by weight (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) Fatty acid amide 0.05 parts by weight (stearic amide / arachidic amide) / Behenic acid amide = 40/30/30) Overcoat layer coating solution O Polyvinyl alcohol (degree of saponification 90 mol%, polymerization degree 1000) 5 parts by weight (Nonionic surfactant manufactured by Nippon Emulsion Co., Ltd.) Water 95 parts by weight

Examples 5 and 6 The following backcoat layer coating solution B (I) was used in place of the backcoat layer coating solution B (I) -1.
A lithographic printing plate was prepared in the same manner as in Example 4 except that -2 or B (I) -3 was used. The lithographic printing plates thus prepared were designated as e and f, and the friction coefficient between the overcoat layer and the backcoat layer was measured (Table 1). Backcoat layer coating solution B (I) -2 Saturated copolymerized polyester resin 3.0 parts by weight (terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol = 1: 1: 1: 1, molecular weight 18,000, glass transition) (Point 67 ° C) Methyl ethyl ketone 100 parts by weight Megafac F-177 0.05 parts by weight (fluorine surfactant manufactured by Dainippon Ink and Chemicals, Inc.) Fatty acid amide 0.1 parts by weight (stearic amide / arachidic amide) / Behenamide = 40/30/30)

Backcoat layer coating solution B (I) -3 Saturated copolymerized polyester resin 3.0 parts by weight (terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol = 1: 1: 1: 1, molecular weight 18,000) , Glass transition point 67 ° C) Methyl ethyl ketone 100 parts by weight Megafac F-177 0.05 parts by weight (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) Fatty acid amide 0.2 parts by weight (stearic acid amide / Arachidic amide / behenic amide = 40/30/30)

Example 7 In Example 1, the overcoat layer coating solution O-2 was used in place of the overcoat layer coating solution O-1, and the backcoat layer coating solution B (II) described below was used. The sample provided with the back coat layer was used as sample g, and the coefficient of friction was measured in the same manner (Table 1). Backcoat layer coating solution B (II) Phenoxy resin 1255-HX-30 manufactured by Yuka Shell Epoxy Co., Ltd. 3.0 parts by weight Methyl ethyl ketone 70 parts by weight Propylene glycol monomethyl ether 30 parts by weight Megafax F-177 0.05 parts by weight (Fluorine surfactant manufactured by Dainippon Ink and Chemicals, Inc.) Fatty acid amide 0.03 parts by weight (stearic amide / arachidic amide / behenic amide = 40/30/30)

[Comparative Example 1] Overcoat layer coating solution O-
A lithographic printing plate was prepared in the same manner as in Example 1 except that the overcoat layer coating solution O was used instead of 1. The planographic printing plate thus prepared was designated as h, and the coefficient of friction between the overcoat layer and the backcoat layer was measured (Table 1).

The eight types of photosensitive lithographic printing plates obtained as described above were cut into 1030 mm × 800 mm, and 50 sheets were packaged in the form of normal lithographic printing plate products. This 50
Arrangement of the product bundle, Crosfield electronics Inc. Argon ion laser plate setter Celic 8000CTP
And subjected to image exposure at an exposure of 0.15 mJ / cm ² . Thereafter, a developing process was performed. The developing process is carried out in a developing tank of a commercially available automatic developing machine PS-900D (manufactured by Fuji Photo Film Co., Ltd.) having an immersion type developing tank [SiO ₂ ] / [M ₂ O].
1.2, SiO ₂ concentration (% by weight) 1.5 aqueous solution of potassium acid, containing 0.04% by weight of N-alkyl-N, N-dihydroxyethylbetaine amphoteric surfactant, pH 13.
The developer of No. 8 was charged, and the above-described exposed eight types of photosensitive lithographic printing plates were subjected to a development treatment.

In the lithographic printing plates of the present invention of Examples 1 to 7, no stain was generated in the non-image area after the development processing, and no omission of the image area was observed at all. When the coefficient of friction between the overcoat layer and the backcoat layer is out of the range of the present invention (Comparative Example 1), after the development processing, the non-image portion is stained at a high occurrence rate or the image is missing at a high incidence. Was. For the non-image part and image part of these lithographic printing plates,
And where it was observed during removal from the platesetter,
The printing plate of Comparative Example 1 was scratched. Example 1
No such scratches were found in the non-image areas and the image areas of the printing plates Nos. 7 to 7.

[0065]

[Table 1]

[0066]

The photosensitive lithographic printing plate of the present invention has no problem such as abrasion at the time of transporting a plurality of sheets, storing for a long period of time, and taking out from the plate setter.
There is no problem such as printing stains in the non-image part and missing of the image part.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA00 AA01 AA04 AA13 AB03 AC01 AC08 AD01 BC12 BC31 BC43 BC51 BJ00 CA00 DA03 DA18 DA40 EA01 2H096 AA06 BA05 CA03 EA02 EA04 GA08 2H114 AA04 AA15 BA02 DA33 FA01

Claims (2)

[Claims] 1. A photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a surface of an aluminum support having an anodized film on at least one side thereof, wherein an overcoat layer is formed on the photosensitive layer. Having a backcoat layer on the back surface of the support opposite to the photosensitive layer, wherein the coefficient of friction between the overcoat layer and the backcoat layer is from 0.2 to 0.6. The photosensitive lithographic printing plate as described above. 2. The photosensitive lithographic printing plate according to claim 1, wherein the overcoat layer contains at least one nonionic surfactant, or the backcoat layer contains at least one fatty acid amide.