JP2887793B2 - Treatment method of lithographic printing plate material that does not require dampening water - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for treating a lithographic printing plate material requiring no dampening solution. More specifically, the present invention relates to a method for treating a positive-working lithographic printing plate material requiring no dampening solution, wherein the lithographic printing plate material always contains an organic solvent but is developed with an aqueous alkaline developer having a content of 1% by weight or less.

[Conventional technology]

The photosensitive layer of the lithographic printing plate material which does not require a fountain solution is a photopolymerization type described in JP-B-54-26928 and JP-B-56-23150, and a photodimerization described in JP-B-55-22781. Types are known. However, when these photosensitive layers are used, there is a problem that the halftone dot reproducibility is inferior and further deteriorates with time.

As a technique for solving these problems, Japanese Patent Laid-Open No. 1-2148 is disclosed.
No. 39 describes (i) a polymer having at least two photopolymerizable ethylenically unsaturated double bond groups on a side chain and having a film-forming ability soluble or swellable in water or alkaline water. A polymer, (ii) a monomer or oligomer having at least one photopolymerizable ethylenically unsaturated double bond group,
(Iii) A fountain solution-free lithographic printing plate material containing a photopolymerization initiator is disclosed.

[Problems to be solved by the invention]

When a polymer having a carboxylic acid or a sodium salt of a carboxylic acid or the like in a side chain is used as a high molecular polymer (binder resin) as disclosed in Japanese Patent Application Laid-Open No. 1-214839, it can be developed with an alkaline developer. is there. However, in the photosensitive layer using the above-mentioned polymer, the swelling of the photosensitive layer is large when the pH of the alkaline developer is high or when the content of the alkaline agent in the developer is high, probably due to the adhesion between the photosensitive layer and the silicone layer. The silicone layer is easily peeled off from the cured photosensitive layer, and the reproducibility of the shadow portion is deteriorated. Therefore, in the above technique, a relatively low pH developer or a neutral developer is used. But just the developer
If the pH is lowered, the solubility of the unexposed portion of the photosensitive layer is reduced, and the reproducibility of the highlight portion is deteriorated. In the case of a polymer having an acid or the like in a side chain, an organic solvent is required.

However, a developer containing an organic solvent is not preferable in terms of working environment and safety and health. In addition, since the developer pH cannot be made high, it cannot be developed by the conventional automatic developing machine using a high pH developer for PS plates, and it is necessary to provide a separate automatic developing machine, which is uneconomical. , Those improvements were desired.

When the content of the carboxylic acid group or a salt thereof is increased (for example, an acid value of 200 or more) in order to increase the solubility or swelling of the unexposed portion of the photosensitive layer in a low pH or neutral developing solution, Swelling becomes severe, the adhesiveness between the photosensitive layer and the silicone layer is reduced, and the reproducibility of the shadow part is deteriorated.

Further, it has been found that there is a problem that image reproducibility is extremely deteriorated when development is carried out with a developer containing no organic solvent using water or an alkali-soluble binder resin as disclosed in JP-A 1-214839.

Therefore, an object of the present invention is advantageous in working environment and safety and hygiene, and can be developed by a conventional automatic developing machine using a high pH developing solution for PS plate, and in an aqueous alkaline developing solution containing an organic solvent without fail. However, an object of the present invention is to clarify a method for treating a lithographic printing plate material requiring no fountain solution in which the content of an organic solvent is 1% by weight or less.

[Means for solving the problem]

The inventor has conducted intensive studies to achieve the above object,
The present invention has been reached.

The method of treating a fountain solution-free lithographic printing plate material according to the present invention has a photosensitive layer and a silicone rubber layer on a support,
A fountain solution-free lithographic printing plate material, wherein the photosensitive layer contains an alkali-soluble and water-insoluble binder resin and at least one monomer or oligomer having a photopolymerizable ethylenically unsaturated double bond and a photopolymerization initiator. , A water-based alkaline developing solution containing water, an alkali agent and an organic solvent, wherein the content of the organic solvent is 1% by weight or less.

In the present invention, the fact that the binder resin is insoluble in water means that precipitation occurs when a solution dissolved in an appropriate organic solvent is dropped into water.

[Action]

Although the lithographic printing plate material requiring no dampening solution of the present invention contains an organic solvent without fail, the lithographic printing plate material can be developed with an aqueous alkali developer having an organic solvent content of 1% by weight or less.
It is advantageous in working environment and health and safety. Also, if the developer pH is 9
Since the pH can be as high as 1111 or more, it can be economically developed by a conventional automatic developing machine using a high pH developer for PS plates. Further, even when developed with a developer containing no organic solvent, image reproducibility is excellent. Therefore, the object of the present invention is achieved.

[Configuration of the invention]

 Hereinafter, the present invention will be described in detail.

(Support) The support is preferably one that can be set in an ordinary lithographic printing machine and that can withstand a load applied during printing. For example, a metal plate such as aluminum, zinc, copper, steel, and chromium, Metal plates, paper, plastic films and glass plates, resin-coated paper, paper coated with metal foil such as aluminum, plastic films that have been hydrophilized, etc. are plated or deposited with zinc, copper, nickel, aluminum, iron, etc. No. Of these, an aluminum plate is preferable. When an aluminum plate is used, graining treatment such as graining treatment and anodic oxidation treatment may be performed.

The thickness of the support is preferably from 50 to 400 µm, more preferably from 100 to 300 µm.

(Primer layer) A primer layer may be provided on the support. A resin, a silane coupling agent, a silicone primer, or the like can be used for the primer layer, and an organic titanate is preferably used.

As the resin, for example, polyester resin, vinyl chloride-vinyl acetate copolymer, acrylic resin, vinyl chloride resin, polyamide resin, polyvinyl butyral resin, epoxy resin, acrylate-based copolymer, vinyl acetate-based copolymer, phenoxy resin, Polyurethane resin, polycarbonate resin, polyacrylonitrile butadiene, polyvinyl acetate and the like can be mentioned.

Above all, a resin obtained by photocrosslinking or thermally crosslinking a (meth) acrylic acid ester having an alcoholic OH group, for example, a copolymer resin of 2-hydroxyethyl methacrylate is preferable.

The primer layer used in the present invention is preferably crosslinked to improve the solvent resistance of the photosensitive layer to a coating solvent or a developing solution with respect to an organic solvent.

As the crosslinking component, a polyvalent isocyanate compound, a diazo resin, a polyvalent epoxy compound, a compound having two or more polymerizable ethylenically unsaturated double bonds, or the like is used.

Examples of the polyvalent isocyanate compound include diphenylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, coronate E, HL, EH (manufactured by Nippon Polyurethane Industry Co., Ltd., polyvalent isocyanate compound).

As the diazo resin, 4-diazodiphenylamine,
Hexafluorophosphate-formaldehyde resin, 3-methoxy-diphenylamine-4-diazonium salt and 4,4'-
And mesitylene sulfonate salts of condensates of bis-methoxymethyl-diphenyl ether.

Examples of the polyvalent epoxy compound include bisphenol-based epoxy resin, bisphenol F diglycidyl ether, novolak glycidyl ether, glycidyl ether of hexahydrophthalic acid, and triglycidyl isocyanate.

Compounds having two or more polymerizable ethylenically unsaturated double bonds include trimethylolpropane triacrylate, tetramethylolmethane triacrylate,
Examples include allyl acrylate and 1,4-butanediol dimethacrylate. When a compound having an ethylenically unsaturated double bond is used, a polymerization initiator or a photopolymerization initiator is used in combination.

 Preferred among the above crosslinking agents are diazo resins.

(Photosensitive Layer) The photosensitive layer of the present invention comprises an alkali-soluble and water-insoluble binder resin, a monomer or oligomer having at least one, preferably two, photopolymerizable ethylenically unsaturated double bonds, and a photopolymerization initiator. It contains.

A preferred binder resin in the present invention is a copolymer resin having the following composition.

(A) 20 mol% of a monomer unit having phenolic OH
(B) 10 mol% of a monomer unit having alcoholic OH
As described above, preferably 20 to 60 mol% In the present invention, the monomer unit having a carboxylic acid group is not contained in principle, but may be contained within a range not impairing the effects of the present invention, and the amount thereof is 20 mol% or less, preferably 0 to 10 mol%.

Monomers having phenolic OH include N- (3
-Hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) maleimide, o, m, p-hydroxystyrene, o, m, p-hydroxyphenyl-acrylate or o,
m, p-hydroxyphenyl-methacrylate, a ring-opening reaction product of p-hydroxybenzoic acid and glycidyl methacrylate, and a reaction product of salicylic acid and 2-hydroxyethyl methacrylate. Above all, N-
(4-Hydroxyphenyl) acrylamide is preferred.

Examples of the monomer having alcoholic OH include hydroxyethyl acrylate, hydroxyethyl methacrylate, 4-hydroxybutyl (meth) acrylate, 2,3
-Hydroxypropyl (meth) acrylate, tetraethylene glycol mono (meth) acrylate, 1,3-propanediol mono (meth) acrylate, di (2-hydroxyethyl) maleate, cleavage of p-hydroxybenzoic acid and glycidyl methacrylate Ring reaction products, reaction products of salicylic acid and 2-hydroxyethyl methacrylate, and the like can be mentioned.

The binder resin used in the present invention has an acid value (mg of potassium hydroxide required for neutralizing free fatty acids) of 10
It is preferably 0 or less.

Specific examples of the binder resin used in the invention include, but are not limited to, the following.

Hydroxyethyl (meth) acrylate / (meth) acrylic acid / N- (4-hydroxyphenyl) acrylamide copolymer, hydroxyethyl (meth) acrylate / (meth) acrylic acid / N- (4-hydroxyphenyl) acrylamide copolymer (Meth) acrylic acid chloride was reacted with the union, and monohydroxyalkyl (meth) acrylate was added to maleic anhydride / N- (hydroxyphenyl) maleimide / hydroxypropyl (meth) acrylate copolymer by esterification. Glycidyl (meth) acrylate or glycidyl allyl ether added to hydroxyethyl (meth) acrylate / (meth) acrylic acid / N- (4-hydroxyphenyl) acrylamide copolymer; vinyl acetate / p-hydroxy Styrene copolymer Hydroxyethyl (meth) acrylate / p-hydroxyphenyl copolymer, hydroxyethyl (meth) acrylate / N- (4-hydroxyphenyl) acrylamide / vinyl methacrylate copolymer, N- (4-hydroxyphenyl) ) / Hydroxyethyl (meth) acrylate copolymer with toluene diisocyanate / 2-hydroxyethyl (meth) acrylate (1/1
Mol) adduct reacted, hydroxyethyl (meth) acrylate / N- (4-hydroxyphenyl) maleimide copolymer reacted with 2-isocyanatoethyl (meth) acrylate, hydroxybutyl (meth) acrylate / N- (4-hydroxyphenyl) maleimide copolymer, for the purpose of improving the film forming property and flexibility of the photosensitive layer, the solubility in a coating solvent, etc., other monomer components such as styrene, vinyl acetate, It is also preferable to copolymerize acrylonitrile, ethyl (meth) acrylate, methyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, and the like.

It is also preferable to introduce an ethylenically unsaturated double bond such as a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a fumarate group, and a maleate group.

The molecular weight of these binder resins is preferably 10,000 to 500,000, and more preferably 200,000 to 250,000.

The monomer or oligomer having at least one photopolymerizable ethylenically unsaturated double bond used in the present invention includes polyethylene glycol mono (meth) acrylate,
Polypropylene glycol mono (meth) acrylate,
Monofunctional acrylates and methacrylates such as phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, trimethylolethane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate
Acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri (acryloyloxypropyl) ether, tri (acryloyloxyethyl) isocyanurate, (meth) Poly (meth) acrylates such as calcium acrylate, barium (meth) acrylate, glycerin, trimethylolethane, etc. added with ethylene oxide or propylene oxide and then (meth) acrylated, JP-B-48-41708, JP-B-50
-6034, urethane acrylates as disclosed in JP-A-51-37193, JP-A-48-64183,
JP-B-49-43191, JP-B-52-30490, and polyfunctional acrylates and methacrylates such as polyester acrylates disclosed in each publication and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylate acid;
N-methylolacrylamide derivatives disclosed in U.S. Pat. No. 4,540,649 can be mentioned. Further, those introduced as photocurable monomers and oligomers in the Adhesion Society of Japan, Vol. 20, No. 7, pages 300 to 308 can also be used.

The composition ratio between these monomers or oligomers and the binder resin is preferably in the range of 0:10 to 7: 3, and more preferably in the range of 1.5: 8.5 to 5: 5.

As the photopolymerization initiator used in the present invention, a vicinal polyketaldonyl compound disclosed in U.S. Pat.No. 2,367,660, U.S. Pat.Nos. 2,367,661 and 2,36
Α-carbonyl compound disclosed in 7,670 gazette,
Acyloin ether disclosed in U.S. Pat.No. 2,448,828, aromatic acyloin compound substituted at α-position with a hydrocarbon group disclosed in U.S. Pat.No. 2,722,512, U.S. Pat.Nos. 3,046,127 and 2,951,758 Polynuclear quinone compounds disclosed in US Patent No. 3,549,36
Patent No. 7 discloses a triarylimidazole dimer / p-aminophenyl ketone combination, U.S. Pat.
No. 3,870,524, benzothiazole compounds disclosed in U.S. Pat. No. 4,239,850, benzothiazole compounds / trihalomethyl-s-triazine compounds and acridine disclosed in U.S. Pat. No. 3,751,259. And phenazine compounds, oxadiazole compounds disclosed in U.S. Pat.No. 4,212,970, U.S. Pat.No. 3,954,475, JP-A-53-133428.
No. 4,189,323, JP-A-60-105667, JP-A-62-58241, and trihalomethyl-s-triazine compounds having a chromophore group disclosed in Japanese Patent Application No. 61-227489. And benzophenone group-containing peroxyester compounds disclosed in JP-A-59-197401 and JP-A-60-76503.

The addition amount of these photopolymerization initiators is from 0.1 to 20% by weight, more preferably from 1 to 10% by weight, based on the whole photosensitive layer composition.

In the present invention, the photosensitive substance may further contain a filler, a dye, a dye, a pigment, a surfactant for improving coating properties, and other conventional additives and auxiliaries.

These photosensitive compositions are dissolved in an organic solvent such as methyl cellosolve to prepare a coating solution, and the coating solution is coated on a support or a primer layer provided as necessary, using a reverse roll coater, an air knife coater, or a Meyer bar. The photosensitive layer is formed by coating and drying using a normal coater such as a coater or a spin coater such as a wooler.

The thickness of the photosensitive layer is preferably from 0.05 to 10 μm, more preferably from 0.1 to 2 μm.

If necessary, an adhesive layer may be provided on the photosensitive layer by applying and drying the same method.

(Silicone rubber layer) A silicone rubber solution is applied on the photosensitive layer or the adhesive layer provided as needed by the same method as described above,
Heat treatment at a temperature of about 120 ° C. for several minutes to sufficiently cure to form a silicone rubber layer.

As the silicone rubber used in the silicone rubber layer, the main component is a linear organic polysiloxane having an OH group in the main chain or at the terminal of the main chain having a molecular weight of several thousand to several hundred thousand having repeating units as follows. Are preferred.

Here, n is an integer of 2 or more, and R is an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a vinyl group, an aryl group,
It is preferably a silanol group (OH group) in which 60% or more of R is a methyl group. The above silanol group (OH group)
May be in the main chain or at the terminal of the main chain, but is preferably at the terminal.

Silicone rubbers useful in the present invention are those obtained by the condensation reaction of such a silicone base polymer with the following silicone crosslinking agents.

(1) R-SiOR ') (2) R-SiOAc) (3) R-SiON = CR' 2) 2 wherein R is the same meaning as R described above, R 'is a methyl group, an ethyl group And Ac is an acetyl group.

These silicone rubbers are also available as commercial products,
For example, there is YE-3085 manufactured by Toshiba Silicone Co., Ltd.

Further, other useful silicone rubbers are obtained by reacting a base polymer as described above with a silicone oil having the following repeating unit, or a silicone base polymer in which about 3% of R is a vinyl group. It can also be obtained by an addition reaction or a reaction between the silicone oils.

(Wherein, R has the same meaning as R above, m is an integer of 2 or more, and n is an integer of 0 or 1 or more.) In order to obtain a silicone rubber by such a crosslinking reaction, In addition to the components of tin, zinc, cobalt,
An organic carboxylate of a metal such as lead, calcium, manganese or the like, for example, dibutyltin laurate, tin (II) octoate, cobalt naphthenate, or a catalyst such as chloroplatinic acid is added.

In order to improve the strength of the silicone rubber and obtain a silicone rubber capable of withstanding the frictional force generated during the printing operation, a filler may be mixed. Silicone rubber pre-mixed with filler is commercially available as silicone rubber stock or silicone rubber dispersion.If it is preferable to obtain a silicone rubber film by coating as in the present invention,
RTV or LTV silicone rubber disversions are preferably used. Such examples include silicone rubber disversions for paper coating such as Syl Off 23, SRX-257, SH237 manufactured by Toray Silicones.

In the present invention, it is preferable to use a condensation-crosslinking type silicone rubber.

In the present invention, in addition to the above components, a suitable amount of a photosensitizer can be contained in the silicone rubber layer.

It is preferable that the silicone rubber layer further contains a silane coupling agent in order to further improve the adhesiveness with the photosensitive layer.

Examples of the silane coupling agent include the following.

(A) H ₂ NCH ₂ CH ₂ NHCCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ (C) HS (CH ₂ ) ₃ Si (OCH ₃ ) ₃ (d) CH ₂ CHCHSi (OCOCH ₃ ) ₃ (F) CH ₂ = CHSi (OCH ₂ CH ₃ ) ₃ (g) H ₂ NCH ₂ CH ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₂ (CH ₃ ) (h) Chlorosilane The thickness of the silicone rubber layer is , 0.1 to 10 μm, more preferably 0.5 to 2 μm.

(Light transmitting film layer) A light transmitting film may be laminated on the silicone rubber layer.

The light transmitting thickness is preferably from 0.5 to 20 μm, more preferably from 3 to 8 μm.

Next, a method for producing a printing plate requiring no dampening solution using the plate material requiring no dampening solution of the present invention will be described.

A positive film as a manuscript is brought into vacuum contact with the plate surface,
Expose. As a light source for this exposure, a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, or the like that generates abundant ultraviolet rays is used. At this time, if a discontinuous mat layer exists on the light transmitting film or the light transmitting film itself has irregularities, the vacuum adhesion can be improved.

After the exposure, the light transmissive film is peeled off and developed with a developer to remove only the unexposed portions of the silicone rubber layer and the photosensitive layer or the silicone rubber layer.

The developing solution used in the present invention is an aqueous developing solution containing an organic solvent, but having an organic solvent content of 1% by weight or less.

The aqueous developer is a developer containing water as a main component, for example, one described in JP-A-61-275759,
30% by weight or more of water, preferably 50% to 98% by weight,
Examples thereof include a developer containing an organic solvent and a surfactant, and more preferably an alkali agent.

Examples of the organic solvent contained in the developer containing water as a main component include, for example, aliphatic hydrocarbons (hexane, heptane,
“Isoper E, H, G” (trade name of aliphatic hydrocarbons or gasoline, kerosene, etc., manufactured by Esso Chemical Co., Ltd.), aromatic hydrocarbons (toluene, xylene, etc.), or halogenated hydrocarbons ( Alcohols (methanol, ethanol, 1-butoxy-2-propanol, 3-methyl-3-methoxybutanol, β-anilinoethanol, benzyl alcohol, etc.), ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.) Phenyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, dioxane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene glycol dibutyl ether, propylene glycol, dipropylene glycol Lumpur ether, tripropylene glycol methyl ether, polypropylene glycol methyl ether), ketones (acetone, methyl ethyl ketone,
Methyl isobutyl ketone, diisobutyl ketone, 4-methyl-1,3-dioxolan-2-one, etc., esters (ethyl acetate, propyl acetate, hexyl acetate, methyl butyrate, propyl butyrate, diethyl succinate, dibutyl oxalate,
Diethyl maleate, benzyl benzoate, methyl cellosolve acetate, cellosolve acetate, carbitol acetate, etc.).

As the surfactant to be added to the developer of the present invention, an anionic surfactant, a nonionic surfactant, a cationic surfactant and an amphoteric surfactant are used, and specific examples thereof include the following. Examples of the anionic surfactant include: (1) higher alcohol sulfates (eg, sodium salt of lauryl alcohol sulfate, ammonium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, secondary sodium alkyl sulfate, etc.) (2) Fat Aliphatic alcohol phosphate salts (for example,
(3) Alkyl aryl sulfonates (eg, sodium dodecylbenzenesulfonate, sodium isopropylnaphthalenesulfonate, sodium dinaphthalenesulfonate, sodium metanitrobenzenesulfonate, etc.) (4) Alkyl amide sulfonates (5) Sulfonates of dibasic aliphatic esters (eg, dioctyl sodium sulfosuccinate, dihexyl sodium sulfosuccinate, etc.) (6) Formaldehyde condensate of alkyl naphthalene sulfonate (eg, formaldehyde condensation of sodium dibutyl naphthalene sulfonate) Products).

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, glycerin fatty acid ester, and oxyethylene oxypropylene block polymer. .

Examples of the cationic surfactant include an alkylamine salt, a quaternary ammonium salt, and a polyoxyethylene alkylamine.

Examples of the amphoteric surfactant include alkyl betaine, and among them, an anionic surfactant is suitable.

These surfactants can be used alone or in combination of two or more.

The amount of the surfactant used in the present invention is preferably 0.01% by weight to 60% by weight, more preferably 0.1% by weight to 1% by weight.
0% by weight is suitable.

Further, the surfactant used in the present invention is preferably used together with an alkali agent. Examples of the alkali agent include: (1) sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, Or inorganic alkaline agents such as sodium or ammonium triphosphate, sodium metasilicate, sodium carbonate, ammonia, etc .; (2) mono, di or trimethylamine, mono, di or triethylamine, mono or diisopropylamine, n-butylamine, mono, Di or triethanolamine, mono, di or triisopropanolamine,
Organic amine compounds such as ethyleneimine and ethylenediimine are exemplified.

The use amount of the alkali agent is preferably 0.05% by weight to 20% by weight, more preferably 0.2% by weight to 10% by weight.

In addition, a dye such as crystal violet or astrazonelet can be added to a developer to stain an image portion simultaneously with development.

By performing development using the above-described developer, a printing plate on which a concave image portion is formed can be obtained.

〔The invention's effect〕

According to the present invention, it is advantageous in working environment and health and safety,
It can be developed by an automatic processor using a high pH developer for conventional PS plates, and although it always contains an organic solvent,
By developing with an aqueous alkaline developer having an organic solvent content of 1% by weight or less, a lithographic printing plate material requiring no dampening solution and having excellent image reproducibility can be obtained.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited to these examples.

Example 1 (Synthesis of diazo resin-1) 14.5 g (50 mmol) of p-diazodiphenylamine sulfate was dissolved in 40.9 g of concentrated sulfuric acid under ice cooling. To this reaction solution, 1.35 g (45 mmol) of paraformaldehyde was slowly added so that the reaction temperature did not exceed 10 ° C.

The reaction mixture was added dropwise to 500 ml of ethanol under ice cooling, and the resulting precipitate was filtered. After washing with ethanol, this precipitate was dissolved in 100 ml of pure water, and a cold concentrated aqueous solution in which 6.8 g of zinc chloride was dissolved was added to this solution. The resulting precipitate was filtered, washed with ethanol, and dissolved in 150 ml of pure water. To this solution was added a cold concentrated aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved. The resulting precipitate was filtered, washed with water, and dried to obtain diazo resin-1.

(Production of aluminum plate a) An aluminum plate having a thickness of 0.24 mm was immersed in a 3% aqueous sodium hydroxide solution to be degreased, washed with water, and then immersed in a 32% aqueous sulfuric acid solution at a temperature of 30 ° C. and 5 A / dm ^2. Anodize for 2 seconds, wash with water, immerse in 2% sodium metasilicate aqueous solution at 85 ° C for 37 seconds, and further immerse in 90 ° C water (pH 8.5) for 2 seconds.
It was immersed for 5 seconds, washed with water and dried to obtain an aluminum plate a.

(Preparation of Plate Material) A primer layer composition having the following composition was applied to an aluminum plate a, dried at 85 ° C. for 3 minutes, and then subjected to a 1000 mJ / cm ² entire surface exposure using a 3 KW ultra-high pressure mercury lamp. 100 ° C
For 4 minutes to form a 0.8 μm thick primer layer.

[Primer layer composition] (1) Diazo resin-1 8 parts by weight (2) 2-hydroxyethyl methacrylate, methyl methacrylate copolymer resin having a molar ratio of 34 / 66-192 parts by weight (3) Methyl cellosolve 900 parts by weight Next, a photosensitive composition having the following composition was applied to the primer layer at a thickness of 3.0 mg / dm ² and dried at 100 ° C. for 2 minutes to form a photosensitive layer.

[Photosensitive composition] (1) 2-hydroxyethyl methacrylate: N- (4-
(Hydroxyphenyl) methacrylamide: 60 parts by weight of vinyl methacrylate (molar% ratio 20/70/10) copolymer resin (2) 30 parts by weight (3) Kayacure-DETX (Nippon Kayaku Co., Ltd., photopolymerization initiator) 5 parts by weight (4) Kayacure-FEP (Nippon Kayaku Co., Ltd., photopolymerization accelerator) 4 parts by weight (5) Victoria Pure 1 part by weight of blue BOH (manufactured by Hodogaya Chemical Co., Ltd., 1 part by weight) (6) 900 parts by weight of methyl cellosolve Next, the following silicone rubber composition was applied on the above-mentioned photosensitive layer to a dry weight of 1.8 g / m ² , Dry at 4 ° C. for 4 minutes.

[Silicone rubber layer composition] Dimethylpolysiloxane having hydroxyl groups at both ends 100 parts by weight (molecular weight 82,000) Triacetoxymethylsilane 10 parts by weight Dibutyltin laurate 0.8 parts by weight Isopar E (manufactured by Esso Chemical) 900 parts by weight Polyethylene terephthalate having a thickness of 5 μm was laminated on the silicone rubber layer.

After bringing the positive film into close contact with the upper surface of the plate material under vacuum, exposure was performed using a metal halide lamp as a light source,
The light transmitting film was peeled off.

Next, after being immersed in the following developer 1 for 1 minute, the surface of the plate material was rubbed with a pad impregnated with the developer to remove the unexposed portions of the silicone rubber layer and the photosensitive layer. A printing plate in which 99% of halftone dots were well reproduced was obtained.

Furthermore, the image area of the printing plate could be vividly dyed by applying a dyeing solution having the following composition to a cloth, lightly rubbing the plate, and then washing with water.

(Developer-1) pH 13.1 Propylene glycol 0.3 parts by weight p-tert-butylbenzoic acid 1.0 parts by weight Potassium hydroxide 1.0 parts by weight Polyoxyethylene lauryl ether 0.2 parts by weight Potassium metasilicate 3.0 parts by weight Water 93 parts by weight (development) Liquid-2) pH10.6 Benzyl alcohol 8 parts by weight Perex NBL (Kao Atlas anionic surfactant 3)
5% by weight aqueous solution 5 parts by weight Diethanolamine 2 parts by weight Water 85 parts by weight (Staining solution) Solfit (solvent manufactured by Kuraray Isoprene Chemical Co., Ltd.) 20 parts by weight Leodol TW-0120 (Kao Corporation surfactant) 0.5 part by weight Benzyl alcohol 5.0 parts by weight Victoria pure blue BOH 1.0 parts by weight Water 100 parts by weight In addition, when the positive PS plate SMP-N (manufactured by Konica Corporation) was developed using Developer-1, good development was achieved. I was able to.

Comparative Example 1 A plate material was obtained in the same manner as in Example 1 of JP-A-1-214839. When this plate material was developed with the developer 1 of Example 1, 90% of the halftone dots were crushed and the image reproducibility was poor.

Comparative Example 2 A plate material was obtained in the same manner as in Example 1 of JP-A-1-214839. When this plate material was developed with the developing solution-2 of Example 1, 5-90% of halftone dots were reproduced, and the image reproducibility was poor.

Example 2 The photosensitive composition of Example 1 was changed as follows.

(1) 2-hydroxyethyl methacrylate, N- (4
-Hydroxyphenyl) maleimide, a resin obtained by adding 2-hydroxyethyl methacrylate by half esterification to a copolymer resin of maleic anhydride (40/50/10 mole ratio)
65 parts (2) 4: 1 adduct of glycidyl methacrylate and metaxylenediamine 20 parts (3) Trimethylolpropane triethoxytriacrylate 10 parts (4) Tetramethylolmethane tetraacrylate 5 parts (5) Kayacure DETX 5 parts ( 6) Kayacure FEP 3 parts (7) Victoria Pure Blue BOH 1 part (8) Methyl lactate 900 parts A plate material was formed in the same manner as in Example 1 except for the above.

Next, a printing plate was produced in the same manner as in Example 1, and developed with Developer-1. 2-99% of halftone dots could be reproduced well.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Satoshi Goto 1 Konica Sakuracho, Hino-shi, Tokyo Inside Konica Corporation (72) Inventor Hiroshi Tomiyasu 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation In-house (72) Inventor Akio Kasakura, 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Chemical Research Institute (56) References JP-A 1-237663 (JP, A) JP-A 1-214839 (JP, A) JP-A-63-280251 (JP, A) JP-A-63-213848 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/00, 7/32

Claims (1)

(57) [Claims] A photosensitive layer and a silicone rubber layer are provided on a support, wherein the photosensitive layer has at least one photopolymerizable ethylenically unsaturated double bond which is an alkali-soluble and water-insoluble binder resin. A method in which a fountain solution-free lithographic printing plate material containing a monomer or oligomer having a photopolymerization initiator is treated with an aqueous alkali developing solution containing water, an alkali agent and an organic solvent, wherein the content of the organic solvent is A method for treating a lithographic printing plate material requiring no dampening solution, wherein the amount is 1% by weight or less.