JPS6273269A - Processing method for photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To make stable formation of a lithographic printing plate having good quality even from a PS plate preserved for a long period of time by subjecting the plate to a desensitization process prior to an erasing process so that the generation of ink stains is decreased even when the PS plate is subjected to the erasing process. CONSTITUTION:The lithographic printing plate obtd. by developing the PS plate is subjected to the desensitization process prior to the erasing process. The desensitization process may be made right after the development or after washing with tap water or circulating water or after the process with an aq. soln. contg. a surface active agent. The desensitizing agent used for the desensitization process consists of a water soluble high-polymer compd. and water as essential components and may contain a surface active agent, acid, water soluble salt, wetting agent, org. solvent and antiseptic and mold inhibitive agent, etc., as necessary. A natural high polymer, semi-natural polymer and synthetic polymer are incorporated into the water soluble high-polymer compd. to be used for the desensitizing agent. A surface active agent is preferably incorporated into the desensitizing agent and an acid is preferably incorporated therein.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a method for processing a photosensitive lithographic printing plate, and more particularly to a method for processing a photosensitive lithographic printing plate in which an image is erased after development.

[Prior art 1] In the plate-making process of creating a lithographic printing plate from a photosensitive lithographic printing plate (hereinafter simply referred to as a PS plate), in many cases an erasing process is performed to remove unnecessary image areas after development due to grading. It is done.

In this erasing process, the image area is generally removed using a solution containing a fi-containing solvent, an acid, or the like. That is, it contains organic solvents, acids, thickeners, water, etc. that dissolve the image area.
A widely used method is to apply the 1'4 removal liquid to unnecessary image areas, rub it with a brush or the like to dissolve and remove the image area, and then wash it away with water.

Pretreatment for erasing includes a method of washing with a large amount of water after development, a method of washing with circulating water, and a method of washing with a large amount of water after development.
115045 and No. 59-227495, in which a solution containing a surfactant is used is generally used.

[Problem to be solved by the invention 1 However, according to the results of the studies conducted by the present inventors, the boundary between the part to which the erasing liquid was attached and the surrounding area
When printing, ink may adhere to the f region, causing stains on printed matter and significantly reducing work efficiency.
It has been found that the occurrence of such a phenomenon is common in the case of the plate-making method described in No. 9994, in which the Negative type PS plate and the Bot type 18 type are treated with the same developer. In addition, such stains tend to occur more easily as the storage period of the PS plate increases from manufacture to use.

It is an object of the present invention to provide a processing method for 18th printing plates that is less likely to cause ink smear as described in I1IF even when an erasing process is performed.

[1] Even in the Ps version preserved for the period of time, the pond of the present invention? Another object of the present invention is to provide a processing method that reduces the occurrence of stains when printing is performed after 1'i removal processing.Another object of the present invention is to provide a processing method that can process a negative 18 plate and a positive PS plate with the same developer; It is also an object of the present invention to provide a processing method for 18th printing plates that causes less staining after the erasing process Pr.

[Problem] Measures to solve the problem 1 The above-mentioned [J objective is to develop the photosensitive lithographic printing plate or erase the recovered image? ? In the method for processing a photosensitive lithographic printing plate, the above-mentioned ? This was achieved by a photosensitive lithographic printing plate processing method in which the vf feature is to perform a desensitization treatment before the 1''i removal treatment.

The present invention will be explained in detail below.

The negative 18th plate and the positive PS plate, which are one of the processing targets in the present invention, are those that are developed with an alkaline developer containing water as the main solvent, and are soluble when exposed to light. A photosensitive layer having a variable temperature is coated on the support (1-1), or a soluble layer on which an image-wise resist layer can be formed by electrophotography or the like is provided on the support (1-).

Supports used for the 18th edition include paper, plastics (e.g. polyethylene, polypropylene, borisnarene, etc.), laminated paper, aluminum (including aluminum alloys), metal plates such as zinc, copper, etc., and diacetic acid. Cellulose, cellulose triacetate, cellulose propionate, polyethylene terephthalate, polyethylene,
Examples include plastic films such as polypropylene, polycarbonate, polyvinyl acetal, etc., paper or pufstinok film laminated or vapor-deposited with metals, aluminum or chrome-plated copper plates, etc.) Also particularly preferred are aluminum and aluminum-coated composite supports.

Further, the surface of the aluminum material is preferably roughened for the purpose of increasing water retention and adhesion to the photosensitive material.

Examples of surface-opening methods include generally known knob methods such as brush polishing, ball polishing, electrolytic etching, chemical etching, liquid honing, and sandblasting, and the introduction of these methods is preferred. Examples include brush polishing, electrolytic etching, chemical etching, and liquid honing, and among these, a surface-opening method involving the use of electrolytic etching is particularly preferred. The electrolytic bath used in electrolytic etching is an aqueous solution containing an acid, an alkali, or a salt thereof, or an aqueous solution containing an organic solvent. I prefer liquid17.

Furthermore, the aluminum plate that has been subjected to the flattening treatment is desmutted with an acid or alkali aqueous solution, if necessary.

The aluminum plate thus obtained is preferably subjected to an anodizing treatment, and particularly preferred is a method of treatment in a bath containing sulfuric acid or phosphoric acid. Furthermore, if necessary, surface treatment such as pore sealing treatment and immersion in an aqueous solution of potassium zirconate can be performed.

The photosensitive layer of the 18th plate used in the present invention contains a photosensitive substance as an essential component, and the physical and chemical properties of the photosensitive substance change upon exposure or subsequent development treatment, such as Items that have a difference in solubility in developing solutions due to exposure, items that have a difference in intermolecular adhesive strength before and after exposure, items that have a difference in affinity for water and oil due to exposure or subsequent development processing, and electrophotography. Depending on the method, it is possible to use a method that forms the image area.

Typical photosensitive substances include, for example, photosensitive diazo compounds, photosensitive azide compounds, compounds with ethylenically unsaturated double bonds, epoxy compounds that polymerize with acid catalysts, silyl ether polymers that decompose with acids, and C-0-
Examples include compounds having a C-group.

Examples of photosensitive diazo compounds include 0-quinone noasite compounds, which are bon-type compounds that become alkali-soluble when exposed to light, and yf aromatic noazonium salts, which are ne-type compounds whose solubility decreases when exposed to light.

Examples of branched forms of 0-quinonenoacite compounds include, for example, JP-A-47-530:1, JP-A No. 4B-69802, JP-A No. 4
No. 8-68803, No. 49-38701, No. 56-1
No. 044, No. 56-1045, Special Publication No. 41-112
No. 22, No. 43-28403, No. 45-9610,
Publications No. 49-17481, U.S. Patent #IJ2, 7
No. 97,213, No. 3,046,120, No. 3,1
No. 88,210, '1,454,400, No. 3,
No. 544,323, No. 3,57g, No. 917, No. 3,
674°495, British Patent No. 3,785,825, British Patent No. 1,277.602, British Patent No. 1,251,345, British Patent No. 1,267.005, British Patent No. 1,329,888.
No. 1. : HlO, No. 992, German Patent No. 85
4.890, etc., and the present invention can be preferably applied to the 18th edition in which these compounds are used alone or in combination as photosensitive components. Toru.

These photosensitive components include 0-quinonediazide sulfonic acid ester or 0-quinonediazidecarboxylic acid ester of an aromatic hydroxy compound, and 0-quinonediazide sulfonic acid or 0-quinonediazidecarboxylic acid amide of an aromatic amide 7 compound, Also included are those in which these 0-quinone noaside compounds are used alone, and those in which they are mixed with an alkali-soluble resin and this mixture is provided as a photosensitive layer.

For the alkali-soluble resin, 7-borac type phenol 0 (
Specific examples include phenol formaldehyde TH fat, cresol formaldehyde 1 fat phenol cresol mixed formaldehyde resin, cresol xylenol mixed formaldehyde resin, and the like.

Furthermore, as described in JP-A No. 50-125806, in addition to 7-ethyl street resins such as H, carbon atoms of 3 to 8 carbon atoms such as t-butyl 7-enol formaldehyde resin are used.
A combination of 7 ether substituted with an alkyl group or a condensate of cresol and formaldehyde is also applicable.

If necessary, additives such as dyes, plasticizers, and components imparting printing performance can be added to the photosensitive layer containing the 0-quinonenoanodo compound as a photosensitive component.

The present invention can be applied to a photosensitive layer containing an 0-quinone noasite compound as a photosensitive component, in which the amount per unit area of the photosensitive layer is at least in the range of about 0.5 to 7 Bi/@2.

There is no particular need to change the image fl of a positive PS plate to which the method of the present invention is applied, and a conventional method may be followed.

A typical photosensitive component of the neutral type photosensitive layer is a diazo compound, for example, a diazo resin which is a condensate of noazonium salt and/or p-diazophenylamine and formaldehyde, as described in Japanese Patent Publication No. 7964/1983. 7-ethyl salt or fluorocapric acid salt of p-diazodiphenylamine described, 3-methoxydiphenylamine + diazonium chloride, 4-nitrodi-7enylamine and formaldehyde described in Japanese Patent Publication No. 49-48001 2-methoxy-4-hydroxy-5benzoylbenzene sulfonate of a condensate of ρ-diazodiphenylamine and formaldermic acid, diazo resin consisting of a tUt medium-soluble salt of a copolycondensate with Examples include tetrafluoroborate, hexafluorophosphate, and the like, which are condensates with formaldehyde.

The present invention can also be preferably applied to black-type PS plates containing these as photosensitive components and other various types of black-type PS plates.

In addition to those using these diazo compounds alone, the present invention can also be applied to those used in combination with various resins in order to improve the physical properties of the photosensitive layer.

Such resins include shellac, derivatives of polyvinyl alcohol, copolymers having an alcoholic hydroxyl group in the side chain described in JP-A-50-118802, and copolymers having alcoholic hydroxyl groups in the side chains described in JP-A-55-155355. Examples include copolymers having the described 7-ethyl hydroxyl group in the IIl chain.

These 01 fats include a copolymer containing at least 50% of structural units represented by the following general formula, COO-(CI・
ter〇)-“■ (wherein, R1 represents a hydrogen atom or methyl J,
2 represents a hydrogen atom, a methyl group, an ethyl group, or a chloromethyl group; 11; n is an integer of 1 to 10; ) and 80 mol% of ttt it unit having an aromatic hydroxyl group to 1
, and 5=90 mol% of acrylic ester and/or methacrylic ester single violet units, and 10 to 200
Includes polymer compounds with an acid value of

The photosensitive layer of the negative type 1] S plate to which the processing η method of the present invention is applied may further contain additives such as dyes, Ni molding, and components imparting printout performance.

” The number of mice per 11 tons of area of the photosensitive layer is at least 0.
．． The present invention can be applied to a range of 1 to 7 g/u2.

There is no particular need to change the image exposure of the negative 15th plate processed by the processing method of the present invention, and a conventional method may be used.

For the negative 15th plate in which a photosensitive material such as a diazo compound of the developer used in the present invention is used, water is contained as a solvent with an alkali agent, an organic solvent, an anionic surfactant, a sulfite, etc. It is preferable to use

As alkaline agents, sodium silicate, potassium silicate,
Ammonium silicate, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, ME
Inorganic alkaline agents such as potassium phosphate, potassium diphosphate, ammonium triphosphate, ammonium diphosphate, sodium metasilicate, sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, etc. Alkali metals such as ethanolamine and tetraalkylammonium hydroxide are useful.

The content of alkaline agent in the developer composition is 0.05
It is preferable to use in the range of ~20 percent heavy acid,
More preferably, it is 0.1 to 10 weight percent.

Ethylene glycol monophenyl ether alcohol and the like are useful as organic solvents.

The content of the organic solvent in the developing solution is preferably 0.5 to 15 weight percent, and a more preferable range is 1 to 5 weight percent.

As anionic surfactants, higher alcohols (CS
-C22) Sulfuric acid ester salt M [e.g., sodium lauryl alcohol sulfate, tyl alcohol sulfate, sodium salt, lauryl alcohol salt, I"Teepol B-81.1 (fF1 product name/Shell Chemical w), second sodium alkyl salt 1, aliphatic alcohol phosphate ester salts (e.g.
sodium salt of heptyl alcohol phosphate, etc.)
, alkylaryl sulfonic acid salts (e.g., sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalene sulfonic acid, sodium salt of cina7talin disulfonic acid, sodium salt of metanitrobenzene sulfonic acid, etc.), sulfonic acid salts of alkylamides ( Example Eva, C+ t11ziCONCl12CHzSO
3Na nato), dibase C11.

There are sulfonate salts of fatty acid esters (eg, sodium sulfosuccinate dioctyl ester, sodium sulfosuccinate dihexyl ester, etc.). Among these, sulfonate salts are particularly preferably used.

11 [Sulfate has the function of dissolving the water-insoluble diazo resin in an aqueous solution, and in particular, when developing a 18-plate consisting of a photosensitive layer combined with a hydrophobic 0-glycan, it can cause stains even after a long period of time has passed since manufacture. It is possible to create a printed version without Useful sulfites include alkali metal salts such as sodium, potassium, and lithium, and alkaline earth metal salts such as magnesium.

On the other hand, for a positive PS plate having a photosensitive layer containing an 0-quinonediazide compound, the alkali agent was added at 0, 1 to 30%.
An aqueous solution containing 0.5 to 20 weight percent, preferably 0.5 to 20 weight percent, is used, and the pH is 9 or higher, more preferably plllo. A range of 5 to 13.5 is used.

The following additives can be added to such a developer in order to further improve the developing performance. For example, JP-A-5
NaC1,K (J, KBr
'4 cn Neutral salt, vj described in JP-A-58-190952 y>EDT^, NTArP4 rate reduction, [Co(NHl) described in JP-A-59-12139 fj
) alc('a, complexes such as CoCl2' 61LO, sodium alkylnaphthalene sulfonates described in JP-A-50-51321, heptanionic or amphoteric surfactants such as N-tetradecyl-N, N-nohydroxyethylbetaine,
Nonionic surfactants such as tetramethyldecynol described in specification II of US Pat. No. 4,374,920, JP-A-5
Cationic polymers such as methyl chloride quaternized product of 1)-trimethylamino7methylboristyrene described in No. 5-95946, copolymerization of vinylbenzyltrimethylammonium chloride and acrylic acid Sorg described in Special Publication +111 No. 142528/1983 Ampholytic polymer electrolytes such as conjugates, reducing inorganic salts such as sodium sulfite described in JP-A No. 57-192952, inorganic lithium compounds such as lithium chloride described in JP-A-58-59444,
Organolithium compounds such as lithium benzoate described in JP-A-34442, S described in JP-A-59-75255
i, organometallic surfactant containing Ti'i9, JP-A-5
9-84241 (M compound), quaternary ammonium salts such as tetraalkylammonium oxides described in European Patent No. 101010,
Examples include organic solvents such as benol alcohol and ethylene glyfur monophenyl ether.

There are various conventionally known methods for developing the 18th plate using a developing solution (as described in 1-1). Method of immersing in developer, using a sponge containing developer
A method of wiping the photosensitive layer of the plate, a method of applying a developer to the photosensitive layer of the 18th plate using a roller, etc. can be used. Furthermore, these developing methods may be the same or a combination of different methods may be used.

In addition, in order to promote development, after the developer is supplied to the photosensitive layer I- of the 18th plate as described in 11-1, or with the 18th plate immersed in the developer, the surface of the photosensitive layer is brushed with a brush, etc. You can also rub it. Development conditions can be appropriately set depending on the development method used.

The temperature of the developer during use is generally in the range of 5 to 60[deg.]C, preferably 10 to 45[deg.]C, more preferably 25 to 35[deg.]C. The time it takes for the 18th plate to reach the developing zone is 5-60
seconds, total processing time in multiple development zones is 10-90 seconds
Preferably seconds 1. stomach.

Further, a replenisher may be added to each of the above-mentioned developing solutions depending on the fatigue caused by the development process or the absorption of carbon dioxide gas in the air. Various conventionally known compositions and replenishment methods can be used for the replenisher.

In the processing method of the present invention, the lithographic printing plate obtained by developing the 18th plate as described above is subjected to a fat-removal treatment before being subjected to the erasing process, but the desensitization treatment is carried out after the development. It may be carried out immediately, or it may be carried out after washing with running water or circulating water, or after treatment with an aqueous solution containing a surfactant.

The desensitizing agent used in the desensitizing treatment of the present invention contains a water-soluble polymer compound and water as essential components, and optionally contains surfactants, acids, water-soluble salts, wetting agents, organic solvents, and preservatives. It can contain a fungicide and the like.

The water-soluble molecular compounds used in the desensitizing agent include natural polymers, semi-natural products, and synthetic products.

Natural polymers include starches such as Japanese starch, potato starch, kubioka starch, wheat starch and corn starch, and those obtained from algae such as Karanunan, laminaran, seaweed mannan, funori, Irish moss, agar and sodium alginate. plant mucilage such as succulent mallow, mannan, quince seed, bectyl, tracanthum, karaya gum, xanthine gum, guarbing gum, locust bingham, gum arabic, carob gamma and benzoin gum, dextran, glucan, levan, etc. Examples include microbial mucilages such as homopolysaccharides and heteropolysaccharides such as sacsi/glucan and xanthan gum, protein products such as glue, gelatin, casein and collagen sugars. In addition to alginate propylene glycol ester, semi-natural products (semi-synthetic products) include viscose, methylcellulose, ethylcellulose, methylethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxybropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, and hydroxypropylmethylcellulose. Examples include fiber cord derivatives such as 7-talate and modified starch. Modified starches include roasted starches such as white dextrin, yellow dextrin, and British gum, enzyme-modified dextrins such as enzyme dextrin and Schardinger dextrin, acid-decomposed starch as shown in solubilized starch, oxidized starch as shown in dialdehyde starch, Esterified starches such as Muran, modified pregelatinized starch and undenatured pregelatinized starch, pregelatinized starch such as phosphoric acid starch, fatty starch, sulfuric acid starch, nitric acid starch, xanthodic acid starch and carbamic acid starch , etherified starches such as carboxyalkyl starch, hydroxyalkyl starch, sulfus alkyl starch, cyanoethyl starch, allyl starch, bennor starch, carbamylethyl starch and dialkylamialkyl starch, methylol cross-linked starch, hydroxyalkyl cross-linked starch, phosphoric acid Crosslinked materials such as X7 and dicarboxylic acid crosslinked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer,
Starch polyvinyl acetate copolymer, starch polyacrylonitrile copolymer, cationic starch polyacrylic ester copolymer, cationic acid starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, etc. Examples include starch graft copolymers. Synthetic products include polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinylethyl ether, and polyvinyl isobutyl ether, sodium polyacrylate, partially saponified polyacrylic ester, and polyvinyl alcohol. partially saponified acrylic acid ester copolymers, polyacrylic acid derivatives and polymethacrylic acid derivatives 19 such as polymethacrylates and polyacrylamides, polyethylene glyfur, polyethylene oxide,
Examples include polyvinylpyrrolidone, a copolymer of polyvinylpyrrolidone and vinyl acetate, carboxyvinyl polymer, styrene maleic acid copolymer, and styrene crotonic acid copolymer. Among these, those obtained from algae, vegetable mucilages, textile derivatives, modified starches, alginate propylene glycol esters, and synthetic products are preferably used because they have good film-forming properties on printing plates. More preferably sodium alginate, alginate propylene glycol ester, tiger canth gum,
locust bean gum, guarbingum, gum arabic,
Methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose,
These are carboxymethylcellulose, roasted starch, oxygen-modified dextrin, oxidized starch, acid-decomposed starch, pregelatinized starch, polyethylene glycol, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid derivatives, polymethacrylic acid derivatives, polyethylene oxide, and polyvinylpyrrolidone. Vegetable mucilages, cellulose derivatives, and modified starches are preferably used because they have strong protective colloidal properties in emulsions. Roasted starch, oxygen-modified dextrin, oxidized starch, acid-decomposed starch, and pregelatinized starch are preferably used because they do not cause a decrease in the oil sensitivity of the image area. Cellulose derivatives are preferred because they have high emulsion stability due to their thickening effect.

Carboxymethyl cellulose, arabic gum, tora canth gum, locust bingham gum, and guarbing gum are preferable because they have high fat-insensitive properties in non-image areas. Among them, gum arabic 6 is preferred because it has extremely high oil-insensitivity in non-image areas. These water-soluble polymer compounds can be used alone or in combination of two or more.

In particular, two or more selected from the group consisting of sodium alginate, propylene glycol alginate, gum arabic, dextrin, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone. Use of a water-soluble polymer compound in combination is preferred from the viewpoints of uniform film formation, prevention of deterioration of oil sensitivity in image areas, protective colloid performance of the emulsion, and emulsion stability of the emulsion. Containing gum arabic and using one or more other water-soluble polymer compounds (-) improves the hydrophilicity and desensitization of non-image areas without reducing the oil sensitivity of image areas. The ratio of gum arabic to all other water-soluble polymer compounds is preferably 4:1 to 1:15, more preferably 2:1 to 1:8. A combination is most preferably used.

The water-soluble polymer is contained in a wide range of concentrations, but generally from about 0.001 to about 20% by weight based on the total weight of the desensitizing agent.
It is used in an amount of 0.01 to 5% by weight, more preferably 0.01 to 1% by weight.

It is preferable that the desensitizing agent used in the present invention further contains a surfactant.

Examples of such surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyrylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, and 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 moieties Esters, polyoxyethylenated castor oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid jetanolamides, N,N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, Nonionic surfactants such as trialkylamine oxide, fatty acid salts, avicenoates, hydroxyalkanesulfonates, alkanesulfonates, dialkylsulfosuccinates, straight-chain alkylbenzenesulfonates, branched-chain alkylbenzenesulfonates , alkylnaphthalene sulfonates, alkylphenoxypolyoxyethylene pro-sulfonates, polyoxyethylene alkylsulfophenyl ether mu, N-methyl-N-
Sodium oleyl taurine, N-alkyl sulfosuccinic acid monosodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef leg oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate ester salts, polyethylene diethylene 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, polyoxy Anions such as ethylene alkyl 7enyl ether phosphate ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, etc. surfactants, alkylamine salts,
Cationic surfactants such as quaternary ammonium salts, 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 be read as polyoxyalkylene such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc., and these surfactants are also included.
The same applies to the following description. Among these, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyrylphenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters,
Pentaerythritol fatty acid partial esters, propylene gelicol monofatty acid esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene glycerin fatty acid partial esters, polyethylene glycol fatty acid esters, polyoxyethylated chick 1
7 oils, dialkyl sulfosuccinates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfate ester salts, and polyoxyethylene alkylamine salts, like the lipophilic substances mentioned above, affect the oil sensitivity of the image area of the lithographic printing plate. Among these, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyrene phenyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, and pentaerythritol 1 are preferred.
Particularly preferred are 1-key fatty acid partial esters, propylene glycol monofatty acid esters, polyethylene glycol fatty acid Nisdels, dialkyl sulfosuccinates, and alkyl sulfate ester salts. In addition, in the case of nonionic surfactants, li 1. It is preferable that n is 14 or less because it has a high effect of stabilizing the emulsion, and more preferably 81.8 is 11 or less, and in the case of a non-emulsifying type, II 1. D=111x1- is preferably used. These surfactants can be used alone or in combination, but alkylphenyl-type nonionic surfactants such as polyoxyethylene alkylphenyl ethers and polyoxypropylene dialkylphenyl ethers are particularly suitable. combinations of agents and dialkyl sulfosuccinates, combinations of fatty acid ester type surfactants and dialkyl sulfosuccinates, alkylphenyl type nonionic surfactants, fatty acid ester type surfactants and dialkyl sulfosuccinic acids. The combination of salts is preferable because it does not create a gap that is easy to emulsify during the production of the desensitizing agent, and has the effect of suppressing the fat sensitivity of the image area [7].Furthermore, fatty acid ester type When surfactants and dialkyl sulfosuccinates are used together, the fatty acid ester surfactant may be a combination of at least two fatty acid ester surfactants (for example, sorbitan monooleate and sorbitan mo7late). It is preferable to use a mixture of 1 and 2) because the stability of emulno-a is improved when the developer components are mixed in.The surfactant is used in an amount of about 0.5 to about 20 parts by weight based on the total weight of the desensitizing agent. acid%, more preferably 1
It can be used in the range of ~10 double stars.

It is preferable that the desensitizing agent used in the present invention further contains an acid.

The acid contained in the desensitizing agent must be washed before use. The main purpose of this is to adjust the pH of e-fat oxidation 1] 11 to an acidic range, preferably in the pH range of 1 to 5, more preferably in the pH range of 5 to 3. For example, phosphoric acid,
Polymerized phosphoric acids such as pyrophosphoric acid, tetraphosphoric acid, tripolyphosphoric acid, and hexametalyphosphoric acid; inorganic acids such as boric acid, hydrochloric acid, sulfuric acid, and nitric acid; or, for example, succinic acid, oxalic acid, citric acid, malic acid,
Organic acids such as maleic acid, phytic acid, lactic acid, 1)-toluenesulfonic acid, organic phosphonic acid, and benzenesulfonic acid can be used, and these can be used alone or in combination.

Among these, phosphoric acid, polymerized cationic acid, malic acid, phytic acid, and organic phosphonic acid are particularly preferred. The amount of acid to be used may be such that the pH of the desensitizing agent is in the acidic range, and is approximately 0.01 to 5% by weight.

It is preferable that the desensitizing agent further contains a water-soluble salt as a buffering agent. This makes the non-image area more hydrophilic when the desensitizing agent is applied to the lithographic printing plate. For details on buffering agents, see, for example, [Chemical Handbook Basic Edition ■1 Edited by the Chemical Society of Japan, February 20, 1971, 5th edition published by Maruzenrin Shikisha Co., Ltd., 13
12 to 1320, and these can be applied as is.

Suitable aqueous salts include molybdic acid, boric acid, nitric acid, sulfuric acid,
Salts of inorganic acids such as phosphoric acid and polyphosphoric acid, and salts of organic acids such as acetic acid, oxalic acid, tartaric acid, benzoic acid, succinic acid, citric acid, malic acid, lactic acid, tannic acid, p-)luenesulfonic acid, etc. can give. More preferred salts are water-soluble alkali metal salts and ammonium salts, and particularly preferred are molybutates such as ammonium molybdate, nitrates such as potassium nitrate, sulfates, phosphates such as sodium phosphate, potassium tetrapolyphosphate, and trimetaphosphate. Polyphosphates such as sodium, oxalates such as sodium oxalate, tartrates such as potassium tartrate, succinates such as sodium succinate, and citrates such as ammonium citrate. Such water-soluble salts can be used individually or in combination, and it is preferred that the total amount of the salts be about 10% by weight or less based on the total weight of the desensitizing agent. More preferably 0.01~
It is used within the range of 6%. Also, the desensitizing agent 111
1 is preferably between 1 and 10. In order to suppress the deterioration of the oil sensitivity of the image area, a ratio of 1 to -8 is preferable. Most preferably, when pl+2.0 to 6.0, the desensitizing effect on non-image areas is high. It is possible to further dissolve and contain a lipophilic substance in the desensitizing agent. In addition, J: The emulsion stability of the desensitizing agent is further improved. 1-1 The liposensitivity of the image area can be further reduced by less than 1 degree. Preferred lipophilic substances and 1. There are lipophilic 0I fats used as vehicles for lithographic printing inks.

Specifically, 7-formaldehyde resin, furesol formaldehyde layer, 7-borac type such as t-butyl 7-ether formaldehyde resin: 11-phenol 47111)t, condensation of phenol and xylene with formaldehyde xylene resin, resin made by condensing phenol and mesitylene with formaldehyde, polyhydroxystyrene, brominated polyhydroxystyrene, cashew fil (fat), partial esterified product of copolymer of styrene and maleic anhydride, melamine resin, alkyd resin, polyester resin, epoxy resin, rosin, modified rosin such as hydrogenated rosin and rosin ester,
Mention may be made of petroleum resins such as Giltonite, but among these, preferred are novolac helical7-el-O (fat, rosin and modified rosin).Other preferred lipophilic substances include plasticizers, fatty acids, fatty oils, Waxes are included. Preferred plasticizers include, for example, dibutyl 7-talate, noanyl 7-talate, no-0-octyl 7-talate, no-(2-ethylhexyl) 7-talate, noanyl 7-talate, didecyl 7-talate, cyfuryl 7-thalet, butylbenzyl 7-talate.
Heptatalic acid diesters such as talates, such as aliphatic di-salts such as nooctyl azelate, dioctyl adipate, dibutyl glycol adi-'+9-bate, butyl sebacate, no(2-ethylhexyl) sebacate, butyl sepacate, etc. Epoxidized triglycerides such as 1-boxylated large V oil, phosphoric acid esters such as tricresyl 7-mole 7-ate, trioctyl 7-m 7-ate, trischlorethyl 7-m 7-ate, e.g. benzoic acid; Contains benzoic acid esters.

Among these, particularly preferred are dioctyl adipate, dibutyl sebacate and nooctyl azelate, which are odorless and safe. Preferred fatty acids include caproic acid, enanthic acid, caprylic acid, herargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, valmitic acid, heptadecylic acid, stearic acid, 7-nadecanoic acid, arachidic acid. , behenic acid, lig7selenic acid, cerotic acid, heptacosanoic acid, montanic acid, melisic acid, roughceric acid, isovaleric acid and other saturated fatty acids and acrylic acid, crotonic acid, isocrotonic acid, undecylic acid, oleic acid, elaidic acid ,
Cetoleic acid, erucic acid, brassinonic acid, sorbic acid,
There are unsaturated fatty acids such as linoleic acid, heptolenic acid, arachidonic acid, propiolic acid, stearolic acid, sardine acid, tarylic acid, and lycanic acid. Preferred waxes include carbanal wax, beeswax, spermaceti wax, natural wax, and wool wax. This can improve the property that the hydrophilic component such as the water-soluble polymer compound of the desensitizing agent spreads to the non-image areas of the lithographic printing plate and the flexibility of the film. Preferred examples of wetting agents are polyhydric alcohols, specifically ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, bentanediol, hexylene glycol, tetraethylene glycol, polyethylene glycol, Examples include propylene glycol, tripropylene glycol, glycerin, sorbitol, and pentaerythritol, with glycerin being particularly preferred. The wetting agent is about 0.000.1 to about 1.00% based on the total weight of the desensitizing agent of the present invention.
It is used in a range of 0% by weight, more preferably 1 to 0.1 to 5% by weight.

The desensitizing agent can be removed by containing an organic solvent. Preferred organic solvents are poorly water-soluble, such as turpentine, xylene, toluene, benzene, 11-hebutane, solvent naphtha, kerosene, mineral spirits, petroleum distillates with a boiling point of about 120°C to about 250°C, cyclohexanone. halogenated hydrocarbons such as nochloroethylene, ethylene glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monophenyl ether, ethylene glycol monoethyl ether, and ethylene glycol monoethyl ether. These solvents are used in an amount ranging from about 0.001 to about 10% by weight, more preferably from 0.5 to 5% by weight, based on the total weight of the desensitizing agent.

Desensitizing agents further include sorbic acid, preservatives such as ethyl I)-oxybenzoate, fungicides, propyl gallate, 2,
6-di-t-butyl-4-ethyl 7enol, 2,6-
Antioxidant I such as not-t-butyl-4-methylphenol
F. It is preferable to contain an agent. The preservative effect of the desensitizing agent can be obtained by adding a small amount of these preservatives, anti-mold agents, and anti-oxidant 11/shavings, but preferably in an amount of o, ooi to 5% by weight.

The desensitizing agent used in the present invention may include an emulsion type desensitizing agent, a suspension type desensitizing agent, a non-emulsion type desensitizing agent, a non-staining type desensitizing agent, etc. by appropriately selecting a surfactant, a lipophilic substance, etc. to be contained. Although they can be manufactured in any way such as desensitizing and cutting, emulsion-type desensitizers and subenzidine-type desensitizers have a high ability to prevent a decrease in the oil sensitivity of the image area of a lithographic printing plate. Therefore, it is preferably used. Furthermore, in order to improve the preparation efficiency and transportation efficiency of the desensitizing agent, it is also possible to use a method in which the components are prepared at a high concentration and then diluted with water to a desired concentration at the time of use.

The method of treating the developed plate with a desensitizing agent is as follows:
Various methods are possible, such as dipping, applying with a roller, and spraying from multiple nozzles or using five rollers. By using a small amount of unused desensitizing agent for each plate, it is possible to dramatically reduce the amount of desensitizing agent used per 18 plates to be processed. When the desensitizing agent is repeatedly supplied onto the lithographic printing plate, the amount used is preferably 11/min or more and 401/min or less. More preferably, it is 3 to 201/min. In addition, in the method of supplying a small amount of unused desensitizing agent to the lithographic printing plate for each treatment, it is necessary to uniformly supply the desensitizing agent onto the lithographic printing plate. The amount of desensitizing agent is preferably 11 or less per sale, more preferably 300I111 or less. Furthermore, the desensitization treatment tank may be single or dispersed, and in the case of two or more, each treatment liquid may be different. The plate with the desensitizing agent supplied to the plate surface in this way is then squeegeeed. Methods of squeezing the plate surface of the lithographic printing plate include, for example, scraping out the liquid with an air knife, or using an elastic material such as rubber. A method in which a lithographic printing plate is passed between a pair of elastic rollers coated on the roller surface and the liquid on the plate surface is removed by the nip pressure, or an elastic material with a smooth surface is placed along the conveyance of the lithographic printing plate, It is possible to adopt a method of scraping off the liquid on the plate by bringing the plates into sliding contact. A more effective squeegee method is a method in which a lithographic printing plate is passed through an elastic roller, and a load is applied between a pair of rollers.

More preferably, a third loaded roller is placed on top of the roller.

The elastic materials include natural rubber, cis-polyisoprene rubber, styrene-butadiene rubber, cis-polybutadiene, chlorobrene, butyl rubber, nitrile-butanoene rubber, ethylene propylene rubber, Hypalon (chlorosulfonated polyethylene), acrylic rubber, and urethane rubber. , silicone rubber, fluorine rubber, neoprene rubber, polysulfide rubber, plastics, etc. Butyl rubber, nitrile butadiene rubber, ethylene propylene rubber, acrylic rubber, silicone rubber, fluororubber, and polysulfide rubber have excellent oil resistance and are therefore suitable and preferable for the roller in the desensitized part.

In addition, in a method of passing a lithographic printing plate through the darkness of a pair of elastic rollers with a squeegee, and more preferably in a method of desensitizing by jetting from a number of nozzles, after the lithographic printing plate has passed through the desensitizing process. , the processing device is arranged so that at least one of the conveyance by the pair of rollers and the jetting by the nozzle is stopped (hereinafter simply referred to as "stop 11").
It is preferable that the design is L because it saves unnecessary power. However, during this rest period, the plate surface desensitizing agent often accumulates on the contact area between the pair of rollers and dries and hardens.

In this case, when restarting the processing of the next lithographic printing plate, apply the desensitizing agent I! The thickness tends to be uneven.

As a method to avoid this situation, there is a method in which the pair of rollers is kept rotating even while the desensitizer treatment is stopped, and a large number of nozzles are used during the treatment and/or while the body is being washed. It is preferable to use at least one method such as spraying a desensitizing agent onto the pair of rollers to delay drying of the pair of rollers.

It is preferable that the lithographic printing plate after being squeegeeed as described above is then dried.

In the plate-making method of the present invention, the applied weight of the desensitizing agent after drying is used in the range of o,oot, to IIF/+*'', preferably 0.005g to 0.5y/11+2, and furthermore, o , otl?~0.3g7m2 are particularly preferred.

The erasing liquid used in the erasing process of the present invention includes
-16<147, No. 51-33442, JP-A-1973
-89806, 55-121447, 60-1
Publications No. 7748, Japanese Patent Application No. 60-59288, No. 60
-53165, No. 60-31330, No. 60-132
As described in each specification of No. 62, the main component is a solvent that dissolves, swells, or dissolves the photosensitive layer, and other solvents, acids, water, surfactants, thickeners, etc. are included as necessary. things are used.

Among these, the effects of the present invention are particularly important when an erasing liquid containing a thickener such as silicic acid fine powder or cellulose and water is used.

Specific methods for the tlV removal process of the present invention include applying the erasing liquid to one part of the image area, leaving it for several tens of seconds, and washing with condensed water, and applying the erasing liquid to a soft material such as a brush. There are methods such as rubbing it with water and then washing it with water.

The lithographic printing plate thus obtained can be subjected to steps such as development ink application and desensitization treatment, if necessary.

〔Example〕

A JIS-1050 aluminum plate with a thickness of 0.24 mm was immersed in a 2% hydroxide) +7 um aqueous solution, degreased, then electrochemically phased in a hydrochloric acid aqueous solution, and then After desmutting in an aqueous solution of +7 um (5% hydroxide), Pitt oxidation was performed in a sulfuric acid solution to form an oxide film of 2.097 mm on the surface of the aluminum plate. Wash the obtained aluminum plate with water,
After drying, a photosensitive solution having the following composition was applied to give a dry weight of 2.2 g/m2 to obtain a positive type 18 plate. The positive type 18 plate obtained in above) was stored at room temperature for 2 years.

(Photosensitive liquid) "Esterification reaction product of 7-toquinone (J,2)-noanodo-5-sulfonyl chloride and resorcinol benzaldehyde resin (esterification rate 50%, JP-A-5
Compound described in Publication No. 6-1044)...3.0g
Cresol/novolac resin...12.0
g2-trichloromethyl-5-[β-(2-benzo7lyl)vinyl)-1,L4-oxadiazole...0
．． 09g glutaric anhydride...
o, tag Victoria Pure Blue 8011 (
Hodogaya Chemical Industry Co., Ltd. s! , dye) ...0.1
2g Crystal Violet F...0.
03g1-methyl cellosolve...
・100g This 15th plate after storage was covered with a transparent botchiebu film and heated to 70c using a 2KW metal halide lamp.
Opening light was performed for 60 seconds from a distance of ia.

This is 5i (12/Na2O (molar ratio) is 2.0, S+
02 content of 3% by weight) with IJum aqueous solution
After being developed for 0'', it was washed with water, and then a nonfatting solution having the following composition was applied with a sponge and dried.The amount of application was 0.3 g/brass2 in terms of dry weight.

(Degreasing agent) "Dextrin...40 parts by weight Gum arabic...+60 frit
71 parts 85% phosphoric acid...10 parts by weight Citric acid...25 parts by weight Sodium hydroxide...1 part by weight Sodium dilauryl sulfosuccinate...20 parts by weight Water...500 parts by weight Next, the image part has the following composition? 1'4 liquid was applied with a brush and lightly rubbed for 40'', then washed with water for 1°. After washing with water, printing was carried out on a printing surface and good prints were obtained.

(Erasing liquid) Xylene: 4 parts by weight Diethylene glycol methyl ether: 17 parts by weight Cyclohexanone: 17 parts by weight Nooxane: 5 parts by weight Triacetin: 15 parts by weight: xybrobyl methyl cellulose ... 1 part by weight polyoxyethylene polyoxypropylene ether ... 16 parts by weight phosphoric acid (75%) ... 3 parts by weight Hou 7
Hydroturic acid: 1 part by weight Silicon dioxide: 6 parts by weight Comparative Example 1 The same plate-making process as in Example 1 was carried out except for the desensitization treatment before erasing. When printing, a slight amount of ink adhered to the surrounding areas where the erasing liquid had adhered, which smeared the printed matter.

Example 2 A grained aluminum plate with a thickness of 0.24+u++ was F! in sulfuric acid. After polar acid oxidation, an oxide film of about 2 g/+++2 was formed, thoroughly washed, immersed in an aqueous sodium silicate solution, thoroughly washed with water, dried, and coated with a photosensitive solution having the composition shown below.

Copolymer of 1-parahydroxyphenylmethacrylamide, acrylonitrile, ethyl acrylate, and methacrylic acid (molar ratio in the following order: 8.5:24)
: 60.5 : 7)...5.0 parts by weight Hexafluorophosphate of a condensate of p-diazodiphenylamine and paraformaldehyde...0.5 parts by weight Victoria Pure Blue B011...0.1
Parts by weight (Hodogaya Chemical Industry Co., Ltd.) L methyl cellosolve...100-!
The coating amount after RIFIS drying was 1.8 g/1112.

The thus-obtained exposed plate (type 18) and the exposed positive-type PS plate similar to that used in the examples were processed using the automatic developing apparatus shown in FIG. 1.

A developing solution having the following composition was placed in the developing tank 1, water was placed in the circulating washing tank 2, and a desensitizing agent having the following composition was placed in the desensitizing liquid tank.

Example 1 shows the image area of a positive type 18 plate that has been desensitized.
It was erased in the same way.

After erasing, printing was performed on a printing press, and a good printed matter was obtained. Further, when the negative type 15 plate was directly printed on a printing press, good printed matter was obtained.

Developer solution “Sodium silicate (Sodium silicate, Ir5a No. 3.5)”
g Sodium hydroxide...0,2
゜Potassium sulfite...2.0
gbennoralcohol...bow, Og
Old Pellex axis, (sodium alkylnaphthalene sulfonate (manufactured by Kao Atlas Co., Ltd., solid content 35%)...
10.0g Trufit (3-methyl-3-methoxybutanol Kuraray Co., Ltd. 9I)...2
．． 0g1 water...8
1.3g (desensitizing agent) Dextrin (same as in Example 1)...10 parts by weight Carboxymethylcellulose sodium salt...0.
45 parts by weight Phosphoric acid...0.25 parts by weight Sodium (2-ethylhexyl)sulfosuccinate...0.14 parts by weight Polyethylene oxide (average number of moles added of ethylene oxide 20)
Nonylphenol ether...0.1 parts by weight P-hydroxyethyl benzoate...0.05 parts by weight 1-water...450 parts by weight The block diagram of one embodiment of the apparatus used to carry out the present invention is shown below. It is shown in Figure tI41.

In the figure, 1 is the development path 11! Tank, 2 is circulation washing tank, 3 is insensitive fat here FJ! It's a tank. 4.5 and 6 are respectively −
1-A conveyance pipe for sending the treatment liquids in 1.2 and 3 to the spray vibrator described later, and 7, 8 and 9 are pumps provided in the liquid supply tubes, respectively. and 10
^, 10B and IOc are all processing liquid spray pipes for spraying processing liquid from tank 1 onto the printing plate surface.
Reference numeral 11 denotes a processing liquid spray vibrator for spraying the processing liquid from tank 2 and 12 from tank 3 onto the printing plate surface, respectively. 13 is a guide roller, 14 and 15 are conveyance rollers, 16 is a receiver, and 17 is a brush roller. 18, 19, 20, 21 and 22 are both squeeze rollers, 23 is the exposed 18th plate, 2
4 is the 18th plate after desensitization treatment.

=47- Comparative Example 2 Printing was performed in the same manner as in Example 2, except that the desensitization treatment was not performed.

A thin layer of ink adhered to the periphery of the area where the erasing liquid was applied on the bottom type PS plate, resulting in stains on the printed matter.

〔Effect of the invention〕

According to the present invention, it has become possible to stably produce a lithographic printing plate of good quality even from the 18th plate stored for a long period of time.

Furthermore, it has become possible to process the negative type PS plate and the positive type 28 plate in parallel with the same developer, thereby stably producing a lithographic printing plate of good quality.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of an automatic processor used in an embodiment of the present invention.

Claims (1)

[Claims] A method for processing a photosensitive lithographic printing plate in which a part of the image is erased after the photosensitive lithographic printing plate is developed, characterized in that a desensitization treatment is performed before the erasing process. Processing method.