JPH0511619B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a correcting agent for lithographic printing plates, and more particularly to a correcting agent used for erasing unnecessary image areas (areas that receive printing ink) of lithographic printing plates. It is related to. (Prior Art) Planographic printing plates For example, in planographic printing plates manufactured by photolithography, unnecessary images or image areas that need to be deleted or corrected are inevitably generated, and it is necessary to correct them. Become. For example, dirt, scratches, cuts, etc. on the original film may cause overexposure or underexposure on the printing plate surface, resulting in unnecessary image areas that must be corrected. As correcting agents for removing unnecessary image areas of such lithographic printing plates, those containing glycol ethers and kratons were disclosed in Japanese Patent Publication No. 51-33442 and Japanese Patent Application Laid-open No. 121447-1982. . However, in recent years, there has been a high level of technical demand for correction agents, and not only high erasing speeds but also an increase in correction work for minute areas. There has been an even stronger desire for something that has less adverse effects on (necessary image areas that should not be erased). A further drawback of the prior art is that the insensitivity of the erased traces after burning is significantly reduced. Burning is a heat treatment to strengthen the image area after development, and it is a process that is frequently performed because it dramatically increases the number of printing plates that can be printed. A method for preventing a decrease in hydrophilicity is disclosed in JP-A-51-143409.
This method is disclosed in various publications of No. 52-6205 and is generally practiced. However, the above-mentioned overexposed and underexposed areas (hereinafter referred to as
It's called midtone. ) has extremely poor erasability, so not only is the erasing speed slow, but even if the above-mentioned method to prevent a decrease in hydrophilicity is applied, burning will cause a strong decrease in insensitivity, resulting in problems such as developing ink build-up and printing. This makes it easier to accept printing ink during printing, resulting in printing smudges. (Object of the Invention) Therefore, an object of the present invention is to provide a lithographic printing plate corrector that has extremely little adverse effect on adjacent necessary image areas and can erase only unnecessary image areas. Another object of the present invention is to provide a lithographic printing plate corrector that does not reduce the insensitivity of erased marks regardless of whether or not burning is performed. A further object of the present invention is to provide a lithographic printing plate corrector that has a high erasing speed in image areas and a high overall working efficiency. (Structure of the Invention) In order to achieve the above object, the present inventors have made the present invention as a result of intensive research. A lithographic printing plate correcting agent characterized by containing the following. The correcting agent of the present invention is excellent in that it has significantly improved adverse effects on close-up lines compared to conventionally known ones, and does not reduce its anti-greasiness even when burned after erasing. . moreover,
From the above, it has been found that the present invention is a highly workable correcting agent with high erasing speed and no failure in plate making. The present invention will be explained in more detail below. Examples of ester compounds of fatty acids having 18 or less carbon atoms and glycerin contained in the modifier of the present invention include formic acid, acetic acid, propionic acid, butyric acid, valeric acid,
Examples include liquid mono-, di-, and triester of glycerin with lauric acid, capric acid, myristic acid, oleic acid, little acid, linolenic acid, caprylic acid, riminoleic acid, etc. Among the ester compounds listed above, butyrate esters such as glycerol-di-n-butyrate, glycerol-1-butyrate, and glycerol-tri-n-butyrate, propionate esters such as glycerol tripropionate, and acetate esters are more preferable. . More preferably glycerol monoacetate, glycerol diacetate,
Acetic acid esters such as glycerol triacetate, among which glycerol triacetate is most preferred. Glyceryl esters of fatty acids having 18 carbon atoms or less contained in the modifier can be used alone or in combination, and the purpose of the present invention can be achieved even at low concentrations, but in practice, the total weight of the modifier is It is used at a concentration of 2 to 95%, preferably 3 to 80%. In order to further improve the above-mentioned performance for close-in images, it is contained at a concentration of 5 to 60%, most preferably 7 to 40%. The essential function of a correction agent is to remove unnecessary image areas on a printing plate, but in addition to this essential function, how can it improve incidental performance such as bleeding at the boundaries of erased areas and compatibility with washing water? is also a technique for preparing corrective agents. Therefore, it is preferable to selectively add organic solvent-based compounds other than the compounds of the present invention, acidic substances, thickeners, surfactants, water, coloring pigments, etc. to the modifier of the present invention. These will be explained in detail below. Examples of organic solvent-based compounds other than the compounds of the present invention include ethers, ketones, ketonic acids,
Examples include ketonic acid esters, lactones, alcohols, fatty acids, and other hydrocarbon solvents. Typical ethers are glycol ethers, specifically ethylene glycol monoalkyl ethers such as ethylene glycol methyl, ethyl, isopropyl, and butyl ether, and ethylene glycol dialkyl ethers such as diethylene glycol methyl and ethyl ethers. , diethylene glycol monoalkyl ethers such as isopropyl, isobutyl ether, diethylene glycol dialkyl ethers, triethylene glycol monoalkyl ethers such as methyl, ethyl, and butyl ether of triethylene glycol, triethylene glycol dialkyl ethers, such as ethylene glycol monofluor, enyl (or tril)
ether, propylene glycol monophenyl (or tolyl) ether, diethylene glycol monophenyl (or tolyl) ether, dipropylene glycol monophenyl (or tolyl) ether, triethylene glycol monophenyl (or tolyl) ether, tripropylene glycol monophenyl (or alkylene glycol aryl (or alkylaryl) such as tolyl) ether, trimethylene glycol monophenyl (or tolyl) ether, di-trimethylene glycol monophenyl (or tolyl) ether, tri-(trimethylene glycol) monophenyl (or tolyl) ether; ) Ethers, such as ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate. Examples of ketones include acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl amyl ketone, methyl hexyl ketone, diethyl ketone, ethyl butyl ketone, butylone, diisopropyl ketone, valerone, mesityl oxide, acetylacetone, Examples include acetonylacetone, cyclohexanone, methylcyclohexanone, acetophenone and the like. Ketonic acids include α-ketonic acids represented by pyruvic acid, benzoylformic acid, phenylpyruvic acid, etc., acetoacetic acid, propionyl acetic acid,
Examples include β-ketonic acid represented by benzoyl acetic acid and the like, γ-ketonic acid represented by levulinic acid, β-benzoylpropionic acid and the like. Examples of the ketonic acid ester include methyl, ethyl,
propyl, isopropyl, butyl, isobutyl,
Examples include alkyl esters such as t-butyl, amyl, and isoamyl, allyl esters, allyl alkyl esters, and alicyclic esters. Examples of lactones include butyrolactone, valerolactone, and hexanolactone. Examples of alcohols include aromatic alcohols, alicyclic alcohols, aliphatic monohydric alcohols, and polyhydric alcohols. Aromatic alcohols include, for example, benzyl alcohol, tolylcarbinol, vanillyl alcohol, phthalyl alcohol, α- and β-
Phenylethyl alcohol, α,β-dioxyethylbenzene, 1-phenyl-1-propanol, 2-phenyl-2-propanol, 2-phenyl-1-propanol, 3-phenylpropanol, 4-phenyl-1-butanol , 4-phenyl-2-butanol and other phenylbutanols with saturated aromatic hydrocarbon side chains, and 1-phenyl-2-propyne-1.
- aromatic hydrocarbons with unsaturated bonds in their side chains, such as alcohol, cinnamyl alcohol, etc., and aromatic hydrocarbons with fluorine, bromine,
Some are substituted with halogen atoms such as chlorine and iodine, and substituents such as hydroxyl groups and alkoxy groups. Alicyclic alcohols include, for example, cyclohexanol, cyclopentanol, terpene alcohols, and sterols such as lanolin. Aliphatic monohydric alcohols include, for example, methyl alcohol, ethyl alcohol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, Saturated aliphatic monohydric alcohols such as octadecanol, such as allyl alcohol, oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolenyl alcohol, geraniol,
There are unsaturated aliphatic monohydric alcohols such as propargyl alcohol. Polyhydric alcohols include dihydric alcohols such as ethylene glycol and propanediol, trihydric alcohols such as glycerin, and polyhydric alcohols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and diglycerin. Examples include glycol. Examples of fatty acids include formic acid, acetic acid, acetic anhydride, propionic acid, butyric acid, valeric acid, caproic acid,
Saturated fatty acids such as enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, such as acrylic acid, crotonic acid, undecylenic acid, oleic acid, linoleic acid, ricinoleic acid,
There are unsaturated fatty acids such as linolenic acid. Examples of other hydrocarbon solvents include petroleum fractions with boiling points around 120 to 250°C, toluene, xylene, benzene, turpentine oil, kerosene, N,
Various examples include N-dimethylformamide, dimethylsulfoxide, tetrahydrofuran, N-methylpyrrolidone, dioxane, and ethylene glycol diacetate. Among the organic solvent-based compounds other than the above-mentioned compounds of the present invention, preferred are glycol ethers, ketones, lactones, alcohols, and other hydrocarbon-based solvents. Among them, ethylene glycol monoalkyl ethers, ethylene glycol dialkyl ethers, diethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, monophenyl (or tolyl) ether of ethylene glycol or diethylene glycol or triethylene glycol, propylene glycol or dipropylene glycol or tripropylene. Monophenyl (or tolyl) ether of glycol, diisopropyl ketone, mesityl oxide,
Cyclohexanone, methylcyclohexanone, butyrolactone, valerolactone, hexanolactone, aromatic alcohol, xylene, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, N-methylpyrrolidone, dioxane, ethylene glycol diacetate, erase speed of image area It is more preferable because it has a high value. Most preferably diethylene glycol dimethyl ether, diisopropyl ketone, mesityl oxide,
Cyclohexanone, methylcycloxanone, lactone, monophenyl (or tolyl) ether of ethylene glycol or diethylene glycol or triethylene glycol, monophenyl (or tolyl) ether of propylene glycol or dipropylene or tripropylene glycol, benzyl alcohol, α- or β- Phenylethyl alcohol, tolylcarbinol, phenylpropyl alcohol, phenylbutyl alcohol, cinnamyl alcohol, dimethyl sulfoxide, ethylene glycol diacetate, xylene, N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, dioxane. . Organic solvent-based compounds other than the above-mentioned compounds of the present invention can be used alone or in combination of two or more, and are preferably 5 to 90% by weight based on the modifier of the present invention.
The content ranges from 20 to 80% by weight, most preferably from 30 to 70% by weight. Examples of acidic substances include inorganic acids such as hydrochloric acid, sulfuric acid, persulfuric acid, phosphoric acid, nitric acid, permanganic acid, hydrofluoric acid, borofluoric acid, and hydrosilicofluoric acid, citric acid, malic acid, formic acid, Examples include organic acids such as lactic acid, oxalic acid, trichloroacetic acid, tannic acid, phytic acid, p-toluenesulfonic acid, and phosphonic acid, and salts thereof. Examples of the phosphonic acid include 1-hydroxyethylidene-1,1-diphosphonic acid,
1,2-diphosphono-1,2-dicarboxyethane, 1,2,2,3-tetraphosphonopropane,
2(2'-phosphonoethyl)pyridine, aminotri(methylenephosphonic acid), vinylphosphonic acid, polyvinylphosphonic acid, 2-phosphonoethane-1-sulfonic acid, water-soluble copolymers of vinylphosphonic acid with acrylic acid and/or vinyl acetate etc. can be mentioned. Among these acidic substances, phosphoric acid, hydrofluoric acid, borofluoric acid, hydrosilicic acid, nitric acid, phosphonic acid, and salts thereof are preferred for improving the correction effect. These acidic substances can be used alone or in combination of two or more, and are 0.1 to 10% by weight, preferably 0.3 to 5.0% by weight, particularly preferably 0.5 to 5.0% by weight, based on the total weight of the modifier.
It is contained in a range of 3.0% by weight. Examples of thickeners include inorganic thickeners such as silicic acid fine powder, modified celluloses such as methylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose/Na salt, gum arabic,
Polymer compounds such as polyvinyl pyrrolidone, polyvinyl methyl ether, polyethylene glycol, polypropylene glycol, vinyl methyl ether-maleic anhydride copolymer, and vinyl acetate-maleic anhydride copolymer are exemplified. Among these, modified cellulose, polyvinylpyrrolidone, and the above-mentioned two types of maleic anhydride copolymers are preferred, and modified cellulose such as hydroxypropyl methylcellulose and polyvinylpyrrolidone are most preferred. These thickeners can be used alone or in a mixture of two or more, and the amount added can be changed to achieve the desired viscosity, but preferably 0.5 to 25% by weight based on the modifier of the present invention. More preferably 1 to 15
It is used in a range of % by weight. As surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyrylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters , pentaerythol fatty acid partial esters, propylene glycol monofatty acid esters,
Sucrose fatty acid ester, oxyethylene oxypropylene block copolymer, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester,
Polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylenized castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N,N-bis-2-hydroxyalkylamines, polyoxyethylene Nonionic surfactants such as alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, fatty acid salts, abitienates, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinate ester salts,
Straight chain alkylbenzene sulfonates, branched chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl phenoxypolyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine Sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef leg oil, sulfate ester salts of fatty acid alkyl esters, alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts , fatty acid monoglyceride sulfate ester salts, polyoxyethylene alkyl phenyl ether sulfate ester salts, polyoxyethylene styrylphenyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts, polyoxyethylene alkyl ether sulfate salts Anionic surfactants such as enyl ether phosphate ester salts, partially saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, naphthalene sulfonate formalin condensates, etc. ,
Alkylamine salts, quaternary ammonium salts,
Cationic surfactants such as polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfate esters,
Examples include amphoteric surfactants such as imidazolines. Among the surfactants listed above, polyoxyethylene can also be read as polyoxyalkylene such as polyoxymethylene, polyoxypropylene, and polyoxybutylene. Among these, nonionic surfactants and anionic surfactants are preferred, and surfactants with an HLB of 9 or more are more preferred because each component contained in the modifier mixes well. Furthermore, polyoxyethylene alkyl phenyl ethers, oxyethylene oxypropylene block copolymers, polyoxyethylene sorbitan fatty acid partial esters,
Polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, and polyglycerin fatty acid partial esters are preferable because they improve the image area erasing effect of the correcting agent. Most preferred is oxyethylene oxypropylene block copolymer. These surfactants may be used alone or in combination of two or more, and are contained in an amount of 1 to 40% by weight, preferably 3 to 25% by weight, based on the total weight of the modifier of the present invention. Water is contained in various components such as acids, and in addition to being necessarily added, water may be added selectively, but it has a subtle effect on the performance of the modifier of the present invention. For this reason, the preferable addition amount is 1 to 30% by weight, more preferably 3 to 20% by weight, based on the total weight of the modifier. Colored pigments can be included if visual contrast is desired, and specifically include, for example, crystal violet, safranin, priliant blue, malachite green, acidrhodamine B.
There are dyes such as, inorganic pigments, organic pigments, etc. These colorants are present in an amount of 0.0001 to 0.05% by weight, preferably 0.001% by weight, based on the total weight of the corrective agent according to the invention.
It is used in a range of 0.01% by weight. The correcting agent of the present invention can be applied to planographic printing plates, and is advantageously used when correcting and erasing image areas of planographic printing plates. The lithographic printing plates include () an electrophotographic printing original plate having a photosensitive layer in which inorganic photoconductive particles such as zinc oxide particles are dispersed in a binder resin, and () an inorganic pigment such as titanium oxide in a binder resin. A direct plate plate with an image-receiving layer dispersed in it, on which an image is formed by writing or typing directly on this layer, and () a plain paper copying machine. Forming an oil-based toner image on the above-mentioned direct plate plate by electrophotography and using this as a printing plate, () Utilizing the difference in solubility in the developer between the exposed and unexposed areas of the photosensitive resin. A photosensitive lithographic printing plate (so-called PS plate) that forms a lipophilic image by
Examples include. Among these, the PS plate is widely used due to its excellent image reproducibility, image strength, printing durability, etc., so this PS plate will be explained in detail below. The support of the PS plate is a dimensionally stable plate-like material,
Includes those conventionally used as supports for printing plates. Examples of such supports include paper, paper laminated with plastic (e.g. polyethylene, polypropylene, polystyrene, etc.), aluminum plates (including aluminum alloys), zinc plates, copper plates, iron plates, composite metal plates (e.g. chromium-based Metal plates such as coated iron plates), such as cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Cellulose nitrate, polyethylene terephthalate,
polyethylene, polystyrene, polypropylene,
Plastic films such as polycarbonate and polyvinyl acetal, paper or plastic films laminated or vapor-deposited with metals such as those mentioned above, and aluminum sheets on polyethylene terephthalate films as described in Japanese Patent Publication No. 18327/1982. Includes combined composite sheets, etc. The support of the PS plate has a hydrophilic surface. here,
A hydrophilic surface is a lithographic printing plate mounted on a printing press,
A surface that is wet with dampening water and has the property of repelling printing ink when printed under standard conditions. The surface of the support is preferably subjected to hydrophilic treatment. There are various methods for hydrophilic treatment. For example, in the case of a support having a plastic surface, methods such as chemical treatment, electric discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, laser treatment, etc., and an undercoat layer after these treatments are used. There is a method of applying it. In addition, in the case of a support having a metal surface such as aluminum, graining treatment such as brush polishing and electrolytic polishing, immersion treatment in an aqueous solution of sodium silicate, fluoridated zirconate, phosphate, etc. It can be plated, coated, or anodized. Among the above-mentioned supports, a plate having a grained or anodized aluminum surface, or a chromium-coated iron plate is preferable because it improves the adhesion of the photosensitive layer. Examples of the anodizing bath include aqueous solutions of various acids such as hydrochloric acid, nitric acid, chromic acid, boric acid, sulfuric acid, persulfuric acid, phosphoric acid, sulfamic acid, and oxalic acid. Preferred is phosphoric acid. An aluminum plate that has been grained and further anodized is more preferred. An aluminum plate that has been brush polished and further anodized, or an aluminum plate that has been brush polished and electrolytically polished and further anodized, has particularly good adhesion with the photosensitive layer, so the resulting PS plate has a long printing life. The modifier of the present invention is particularly advantageous because of its high strength. Furthermore, surface roughness is known as one method of expressing the hydrophilicity of a support, and it has been found that this surface roughness also serves as a measure of the adhesiveness of the photosensitive layer. Therefore, the center line average roughness Ra [μm] is preferably 0.40 or more, more preferably 0.50 or more and 0.80 or less. It shows the most preferable adhesion, and the preferable range is 0.60 or more and 0.80 or less. (Measuring equipment: Belten, West Germany, belt meter, tracer RHT3/
50e) The photosensitive composition of the photosensitive layer provided on the hydrophilic surface of the support may include a photosensitive composition containing a diazo compound, such as those described in British Patent Nos. 1,235,281 and 1,495,861. Photosensitive compositions containing azide compounds, photosensitive compositions containing photocrosslinkable photopolymers as described in U.S. Pat. No. 3,860,426; U.S. Pat. No. 4,072,528;
Photosensitive composition containing a photopolymerizable photopolymer as described in JP-A No. 4072527, JP-A-56
Photoconductive compositions as described in JP-A-19063 and JP-A-56-29250, silver halide emulsion compositions as described in JP-A-52-62501 and JP-A-56-111852. Examples include things. Among these photosensitive compositions, photosensitive compositions containing diazo compounds have excellent properties such as storage stability of the photosensitive layer, development performance such as development latitude, image performance such as image quality, ink receptivity, oil sensitivity, abrasion resistance, etc. It is preferred because of its overall excellent printing performance and low pollution properties of the developer used. Photosensitive compositions containing diazo compounds are classified into negative type and positive type. The negative photosensitive composition containing a diazo compound contains a photosensitive diazo compound and preferably a polymer compound. Conventionally known photosensitive diazo compounds can be used, but organic compounds are preferably used. Salts of solvent-soluble diazo resins, such as salts of p-diazodiphenylamine and condensates of formaldehyde or acetaldehyde or benzaldehyde and hexafluorophosphates, salts of toluenesulfonates, 2-hydroxy-4-methoxybenzo Examples include salts with phenone-5-sulfonate. A more preferable example is the following general formula: (In the formula, R ₁ , R ₂ and R ₃ represent a hydrogen atom, an alkyl group or an alkoxy group, R represents a hydrogen atom, an alkyl group or a phenyl group, and X represents PF ₆ or BF ₄
, m is a number from 1 to 200),
Examples include those containing 20 mol% or more, preferably 20 to 60 mol%, of a resin in which m in the formula is 5 or more. The content of the diazo resin in the photosensitive composition is 1 to
70% by weight, preferably 3-60% by weight. Examples of polymer compounds include acrylic acid or methacrylic acid copolymers, crotonic acid copolymers, itaconic acid copolymers, maleic acid copolymers, cellulose derivatives having carboxyl groups in their side chains, and cellulose derivatives having carboxyl groups in their side chains. Polyvinyl alcohol derivatives having carboxyl groups, hydroxyalkyl acrylate or methacrylate copolymers having carboxyl groups in side chains, unsaturated polyester resins having carboxyl groups, etc. are preferably used. More preferably, it is a polymer compound having an acid value of 10 to 300. Further, more preferably, a structural unit represented by the following general formula () and a polymer containing a structural unit represented by the following general formula () described in JP-A-50-118802, JP-A-57-192951 A polymer containing a monomer unit having an aromatic hydroxyl group and a structural unit represented by the general formula () as described in the above specification is used.

【formula】

[Formula] (In the general formula, R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom, methyl group, ethyl group, or chloromethyl group, R ₆ represents a hydrogen atom or a methyl group, and l represents 1 10) As the diazo compound used in the positive photosensitive composition, conventionally known diazo compounds can be used, but representative examples include o-quinone diazides, and o-naphthoquinone diazides are preferable. Examples include compounds. Among o-naphthoquinone diazide compounds, o-
naphthoquinonediazide sulfonic acid ester or o
-naphthoquinonediazidecarboxylic acid esters and o-naphthoquinonediazide sulfonic acid amides or o-naphthoquinonediazidecarboxylic acid amides of aromatic amino compounds are preferred. Preferred hydroxy compounds include condensation resins of phenols and carbonyl group-containing compounds. Examples of the phenols include phenol, cresol, resorcinol, and pyrogallol, and examples of the carbonyl group-containing compounds include formaldehyde, benzaldehyde, and acetone. Preferred hydroxyl compounds include phenol formaldehyde resin, cresol formaldehyde resin, pyrogallol acetone resin, and resorcinol benzaldehyde resin. Typical specific examples of o-quinonediazide compounds include benzoquinone-(1,2)-diazide sulfonic acid or naphthoquinone-(1,2)-diazide sulfonic acid and phenol formaldehyde resin or cresol formaldehyde resin. Ester, ester of naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid and resorcinol-benzaldehyde resin described in JP-A No. 56-1044, US Pat. No. 3,635,709 Ester of naphthoquinone-(1,2)-diazide sulfonic acid and pyrogallol acetone resin described, naphthoquinone-(1,2)-diazide-(2) described in JP-A-55-76346. )-5-sulfonic acid and a resorcinol-pyrogallol-acetone copolycondensate. Other useful o-quinonediazide compounds include JP-A-50
-A polyester having a hydroxyl group at the end as described in Japanese Patent Publication No. 117503 and o-naphthoquinonediazide sulfonyl chloride esterified, p-hydroxystyrene as described in Japanese Patent Application Laid-Open No. 113305-1982. A homopolymer of or a copolymer with other copolymerizable monomers is esterified with o-naphthoquinonediazide sulfonyl chloride.
Bisphenol described in Publication No. 29922
Esters of formaldehyde resins and o-quinonediazide sulfonic acid, condensation of copolymers of alkyl acrylates, acroyloxyalkyl carbonates, and hydroxyalkyl acrylates with o-quinonediazide sulfonyl chloride as described in U.S. Pat. No. 3,859,099. products, reaction products of copolymerization products of styrene and phenol derivatives and o-quinonediazide sulfonic acid as described in Japanese Patent Publication No. 49-17481, and products as described in U.S. Pat. No. 3,759,711. p-
Amides of copolymers of aminostyrene and other copolymerizable monomers with o-naphthoquinonediazide sulfonic acid or o-naphthoquinonediazidecarboxylic acid, and also amides of polyhydroxybenzophenone and o-naphthoquinonediazide sulfonyl chloride. Examples include esterified products. Although these o-naphthoquinone diazide compounds can be used alone, it is preferable to mix them with an alkali-soluble resin and provide this mixture as a photosensitive layer. Suitable alkali-soluble resins include novolac type phenolic resins, specifically phenol formaldehyde resins, cresol formaldehyde resins, and phenol/cresol formaldehyde copolycondensation resins as described in JP-A-55-57841. Contains body resin, etc. Furthermore, as described in Japanese Patent Application Laid-Open No. 50-125806, t-
It is even more preferable to use a phenol substituted with an alkyl group having 3 to 8 carbon atoms, such as butylphenol-formaldehyde resin, or a condensate of cresol and formaldehyde in combination. The content of the o-quinonediazide compound is preferably 5 to 80% by weight, particularly preferably 10 to 50% by weight, based on the total solid content of the photosensitive composition. The content of the alkali-soluble resin is 30 to 30% of the total solid content of the photosensitive composition.
90% by weight is preferred, particularly preferably 50-85% by weight. The photosensitive composition can be provided in multiple layers, and additives such as dyes, plasticizers, and components imparting printout performance can be added as necessary. The coating amount of the photosensitive composition provided on the support is preferably 0.1 to 7 g/m ² , more preferably
It is 0.5 to 4 g/ ^m2 . The modifier of the present invention becomes more effective at 1.5 g/m 2 to 4 g/m ² , and is most effective at 2.0 to 3.0 g/m ² . The PS plate thus obtained is exposed through a transparent original to a light source rich in active light, such as a carbon arc lamp, mercury lamp, metal halide lamp, tungsten lamp, or xenon lamp, and then developed. The developer used may vary depending on the type of photosensitive composition used in the PS plate, but preferably contains at least one of an alkaline agent and an organic solvent, and may vary depending on the type of photosensitive layer. selected. This is described in detail in Japanese Unexamined Patent Publication No. 59-58431. Developers for PS plates with a negative diazo photosensitive layer that are widely used include ethylene glycol monophenyl ether,
Generally, a developer containing benzyl alcohol is used as a developer for a positive PS plate, and the molar ratio of [SiO ₂ ]/[M] = 0.5 to 1.5 ([SiO ₂ ] and [M] are SiO ₂ and the molarity of total alkali metals such as K, Na, Li, etc.), and SiO ₂
It generally contains 0.8 to 8% by weight. Methods for developing a PS plate that has been image-exposed with the above developer include a method of jetting the developer from multiple nozzles, a method of immersing the plate in the developer, and a method of wiping with a sponge moistened with the developer. Various methods known in the art are possible. As mentioned above, if there is an unnecessary image area on the lithographic printing plate obtained by subjecting the PS plate to image exposure and development, the image area can be erased by applying the correction agent of the present invention on the image area. Ru. When the correcting agent of the present invention is applied to the image area of a lithographic printing plate, it is preferable to wash the plate with water after development and use a squeegee to remove the washing water before erasing the plate. A specific method for erasing is to soak a brush in a correction agent, apply it to the image area, leave it for about 10 seconds to several minutes, or lightly rub it with a brush after application, and then wash it off with water. Alternatively, a common method is to rinse it off and simultaneously rub it with a sponge. The lithographic printing plate from which unnecessary image areas have been erased in this way is processed after the usual processing steps such as development inking and/or gumming, or after finishing the development inking and/or gumming treatment after burning. , for printing. The correcting agent of the present invention is advantageously used because it does not cause deterioration in insensitivity due to burning of erased marks. The correcting agent of the present invention can quickly erase unnecessary image areas and has extremely little adverse effect on adjacent images, improving the efficiency of plate-making work.
Furthermore, since the correcting agent of the present invention does not lose its insensitivity even after burning the erased traces, it is possible to eliminate failures during plate making and troubles during printing, improving the efficiency of plate making and printing. The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. In addition, in the following examples, "part" represents a part by weight, and "%" means weight %. Example 1 An aluminum plate with a thickness of 0.3 mm was electrochemically roughened in a nitric acid solution, thoroughly washed, and then anodized in a sulfuric acid solution to form an oxide film of 2.5 g/m ² on the surface of the aluminum plate. was formed. After washing with water and drying, 3 parts of an esterified product of resorcin benzaldehyde resin and naphthoquinone 1,2-diazide-5-sulfonyl chloride synthesized according to the example of JP-A-56-1044 and 9 parts of cresol-formalin novolak resin. Also, a photosensitive solution prepared by dissolving 0.12 parts of Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Industry Co., Ltd.) in 100 parts of 2-methoxyethanol was applied onto the above support using a rotary coater and dried, at a rate of 2.8 g/m ² . A positive PS plate having a photosensitive layer of I put a halftone photo transparency on top of this, 0.8
The plate was exposed for 60 seconds using the metal halide lamp used in Example 1 from a distance of m, and developed with the following developer to obtain a printing plate. (Developer) Potassium silicate A (SiO ₂ 26%, K ₂ O 13.5%)
120 parts 86% potassium hydroxide 15.5 parts Water 500 parts Next, unnecessary image areas were erased using the correction agent of the present invention described below, and were completely erased in 60 seconds. When this printing plate was printed after being burned at 25° C. for 8 minutes, the erased marks were not stained at all. Also, the halftone dots that were 0.2 mm close to the erased area did not show any negative effects such as staining. (Modifier of the present invention) Xylene 5 parts Cyclohexanone 20 parts Diethylene diglycol methyl ether 15 parts Glycerol triacetate 25 parts Hydroxypropyl methyl cellulose 1.8 parts (methoxy groups 28-30%, hydroxypropoxy groups 7-12%, 2 at 20°C % aqueous solution with a viscosity of 4.8 to 7.2 cps.) Pluronic P-85 (manufactured by Asahi Denka Co., Ltd., oxyethylene oxypropylene block copolymer) 12 parts 85% phosphoric acid 2.0 parts 99.5% acetic acid 2 parts Silicic acid fine powder 6.5 parts Water 10 parts Example 2 When unnecessary image areas of the printing plate obtained in the same manner as in Example 1 were erased with the following correction agent of the present invention,
Completely erased in 60 seconds. This printing plate was subjected to burning in the same manner as in Example 1, and development ink was applied (Sakura PS plate development ink SPO-1 manufactured by Konishiroku Photo Industry Co., Ltd.). The erased traces were not smudged at all, and the halftone dots close to the erased areas were free of smudges up to approximately 0.2 mm. (Modifier of the present invention) The modifier of Example 1 except that 20 parts of cyclohexanone was replaced with 20 parts of γ-butyrolactone, and 25 parts of glycerol triacetate was replaced with 25 parts of glycerol diacetate. Comparative Example 1 A correction agent having the following composition similar to that described in JP-A-55-121447 (Example 4) was prepared, and the image area of the printing plate obtained in the same manner as in Example 1 was erased. Burning and inking were performed in the same manner as 2. It was found that the development ink adhered to the halftone erased traces of the obtained printing plate, resulting in a decrease in oil insensitivity. It was also found that halftone dots close to the erased area were smeared with developing ink up to a distance of 1.0 mm, which had a significant negative effect on nearby images. (Known modifier) δ-valerolactone 29.5 parts Ethylene glycol dimethyl ether 30 parts Solvent naphtha (boiling point 140-200°C) 10 parts Hydroxypropyl methylcellulose 1.5 parts (Same as Example 1) Pluronic P-85 (used in Example 1) 10 parts 85% phosphoric acid 5 parts Water 10 parts Silicic acid fine powder 5 parts Example 3 An aluminum plate with a thickness of 0.3 mm was electrochemically roughened in a hydrochloric acid solution, thoroughly washed, and then placed in a sulfuric acid solution. Anodic oxidation was carried out using hot water, and an oxide film of 2.7 g/m ² was formed on the surface. After washing with water and drying, m-cresol formaldehyde resin and naphthoquinone-1,2-diazide-s-
A photosensitive solution prepared by dissolving 5 parts of an esterified product with sulfonyl chloride, 10 parts of a cresol-formalin novolac resin (phenol:cresol = 2:8), and 0.14 parts of Victoria Pure Blue BOH in 100 parts of 2-methoxyethanol was used on the above support. It was coated on a body and dried to obtain a positive PS plate having a photosensitive layer of 2.8 g/m ² . A halftone photographic transparency was placed on top of this, exposed and developed in the same manner as in Example 1 to obtain a printing plate. When the unnecessary image area of this printing plate was erased using the correction agent of the present invention described below, it was completely erased in 60 seconds.
When this printing plate was printed after burning at 260° C. for 7 minutes, there was no printing stain at all in the erased traces, including the intermediate tones. Furthermore, the halftone dots close to the erased area had no negative effects such as printing stains up to approximately 0.2 mm. (Modifier of the present invention) Xylene 4 parts γ-butyrolactone 15 parts Ethylene glycol diacetate 15 parts Diethylene glycol dimethyl ether 15 parts Glycerol monoacetate 15 parts Silicic acid fine powder 7 parts Hydroxypropyl methyl cellulose 1 part Pluronic P-85 9 parts 85% phosphoric acid 2.1 parts water 11 parts Example 4 When unnecessary image areas of the printing plate obtained in the same manner as in Example 3 were erased with the following correction agent of the present invention,
It was completely erased in 15 seconds. When this printing plate was burned in the same manner as in Example 3 and printed using a printing press, the erased marks, including the halftones, did not cause printing stains. Furthermore, there were no negative effects such as printing stains on halftone dots close to the erased area up to around 0.3 mm. (Modifier of the present invention) Xylene 5 parts Diethylene glycol dimethyl ether 15 parts N,N-dimethylformamide 10 parts Cyclohexanone 18 parts Glycerol triacetate 15 parts Hydroxypropyl methylcellulose 1.8 parts Silicic acid fine powder 6 parts Pluronic P-85 13 parts 85% phosphoric acid 2.6 Parts 42% borohydrofluoric acid 1.5 parts Water 10 parts Pigment (Food Red No. 1) 0.002 parts Comparative Example 2 Unnecessary image areas of the printing plate obtained in the same manner as in Example 3 were removed with the following known correction agent. When the printing plate was erased, it was observed with the naked eye that erasing was completed in 60 seconds, but this printing plate was burned in the same manner as in Example 3.
When printed using a printing machine, printing ink adhered to the erased halftone areas, resulting in smudged prints. From this, it can be seen that the correcting agent causes a decrease in the insensitivity when the erased traces are burned. It was also found that printing stains occurred in the halftone dot area 0.7 mm close to the erased area, which had a significant negative effect on the adjacent image. (Known modifiers) Xylene 5 parts N,N-dimethylformamide 15 parts Cyclohexanone 30 parts Diethylene glycol monomethyl ether 15 parts Hydroxypropyl methyl cellulose 1.8 parts Silicic acid fine powder 6.5 parts Pluronic P-85 12 parts 99.5% acetic acid 2 parts 85% phosphoric acid 2.6 parts Water 10 parts Pigment (Food Red No. 1) 0.002 parts Example 5 An aluminum plate with a thickness of 0.24 mm was degreased by immersing it in a 20% aqueous sodium phosphate solution, and then heated at 3 A/m ² in a 0.2 N hydrochloric acid bath. After electropolishing at a current density of , it was anodized in a sulfuric acid bath. At this time, the amount of anodic oxidation is
It was 3.0g/ ^m2 . Further, the pores were sealed with an aqueous sodium metasilicate solution to obtain a support for a lithographic printing plate. A photosensitive liquid having the following composition was applied to this aluminum plate. The film was then dried at a temperature of 90° C. for 2 minutes to obtain a film thickness of 18 mg/dm ² to obtain a negative PS plate. (Photosensitive liquid) Copolymer 5.0 parts Diazo resin 0.5 parts Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.1 part Methyl cellosolp 100 parts However, the above copolymer has a weight ratio of p-hydroxyphenyl methacrylamide/ Acrylonitrile/
Ethyl acrylate/methacrylic acid = 8/24/
It has a composition (molar ratio) of 59.5/8.5, average molecular weight (Mw) = 5.8 x ¹⁰⁴ , and the above diazo resin is p-
It is a hexafluorophosphate salt of a condensate of diazodiphenylamine and paraformaldehyde. A halftone photographic transparent negative was placed on top of this and exposed for 50 seconds from a distance of 0.8 m using the metal halide lamp and Idolfin 2000, followed by development with the following developer to obtain a printing plate. (Developer) Benzyl alcohol 5.0 parts Sodium carbonate 0.5 parts Sodium sulfite 0.5 parts 3-Methyl-3-methoxybutanol 26.5 parts Water 100 parts Next, unnecessary image areas are erased with the following correction agent of the present invention, and the developing ink is When the image was filled in, it was possible to erase it in 20 seconds, and no image remained in the middle tones. Furthermore, the negative effect on close-up lines is
It did not occur up to around 0.1mm. (Correcting agent of the present invention) Glycerol acetate 20 parts Cyclohexanone 30 parts Diethylene glycol monomethyl ether 16 parts Xylene 5 parts Hydroxypropyl methyl cellulose 8 parts Pluronik P-85 8 parts 55% hydrofluoric acid 0.9 parts 60% 1-hydroxyethylidene-1, 1-Diphosphonic acid 2.2 parts Water 10 parts Pigment (Food Blue 101) 0.002 parts Comparative Example 3 The composition of the corrective agent used in Example 6 was
% hydrofluoric acid, 60% 1-hydroxyethylidene-
When a correcting agent (except 1,1-diphosphonic acid) was prepared and the unnecessary image area of the obtained printing plate was erased in the same manner as in Example 6, it could not be erased even after 5 minutes. . Comparative Example 4 The following correction agent having a composition similar to that described in Japanese Patent Publication No. 46-16047 (Example 6) was prepared, and the image area of the obtained printing plate was erased in the same manner as in Example 6.
I couldn't erase it even after several minutes had passed. (Known modifiers) Triethylene glycol 43 parts Methyl ethyl ketone 34 parts Water 9 parts 55% hydrofluoric acid 1.5 parts Hydroxypropyl methylcellulose 2 parts

Claims (1)

[Claims] 1. A lithographic printing plate corrector characterized by containing an ester compound of a fatty acid having 18 carbon atoms or less and glycerin.