JP2814279B2 - Waterless photosensitive lithographic printing plate developer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a developer for a waterless photosensitive lithographic printing plate, and more particularly to a silicone rubber layer which is less likely to be damaged by a brush during development. The present invention relates to a developing solution for a water-free photosensitive lithographic printing plate, in which silicate crystals are less likely to adhere to the lithographic printing plate and the like.

BACKGROUND OF THE INVENTION Conventionally, various waterless photosensitive lithographic printing plates have been known, including those having a structure in which a photosensitive layer and an ink repellent layer are sequentially coated on a support.

This waterless photosensitive lithographic printing plate is developed after being exposed to an image. As a developer used for this, a solution using a hydrocarbon-based organic solvent such as Isobar H or toluene is conventionally known. However, when these hydrocarbon-based organic solvents are used as the developer for a waterless photosensitive lithographic printing plate, there is a problem in safety and hygiene, and in recent years, instead of this, an aqueous developer has been used. The technology that uses is widely used. For example, JP-A-1-257847 discloses that
Describes a developer for developing a waterless lithographic printing plate precursor, specifically, an alkaline aqueous developer containing an organic solvent that dissolves or swells the unexposed portion of the photosensitive layer, a basic compound and a surfactant. Is disclosed. This developer prevents the generation of sludge in the developer by including a basic substance.However, since the developer containing a basic substance has a high pH, the lithographic printing plate precursor without water is used. At the time of development, the adhesiveness between the photosensitive layer and the silicone rubber layer is reduced in the non-image portion which is firmly adhered, and the silicone rubber layer peels off from the photosensitive layer, resulting in poor reproducibility of the shadow portion. There was a problem of becoming.

Therefore, the present inventors have conducted various studies on the above problems, and as a result, by using silicate as a basic substance in the developer, the adhesion between the photosensitive layer and the silicone rubber layer is reduced even at a high pH. It was found that a printing plate having good shadow portion reproducibility could be obtained without using the developing solution.However, when the developing solution was used for an automatic developing machine, the silicone rubber layer was easily scratched by a brush during development, and the automatic If the developing machine is not used for several days, the silicate crystals in the developing solution will adhere to the brush, resulting in an increase in damage to the silicone rubber layer during development. As a result of further study on such points, it was found that when propylene glycol was used in combination with the silicate, a water-free photosensitive lithographic printing plate developer free from such defects was obtained.

[Object of the Invention] Therefore, an object of the present invention is to provide a silicone rubber layer that is hardly damaged by a brush during development, that silicate crystals are less likely to adhere to a brush or the like, and that there is no water having excellent halftone dot reproducibility. An object of the present invention is to provide a photosensitive lithographic printing plate developer.

[Constitution of the Invention] The object of the present invention is to provide a developer for a waterless photosensitive lithographic printing plate having a primer layer, a photocurable photosensitive layer and a silicone rubber layer in this order on a support, wherein the developer is a silicate,
This was achieved by a developer for waterless photosensitive lithographic printing plates characterized by comprising propylene glycol and water.

 Hereinafter, the present invention will be described specifically.

The developing solution of the present invention is mainly for developing a waterless photosensitive lithographic printing plate containing a photocurable photosensitive layer, and the developing solution is composed of silicate, propylene glycol and water. Other developer components can be included as long as they have no adverse effect. The silicate SiO ₂ concentration in the developer is
The range is preferably 0.5% to 6% by weight, more preferably SiO 2
_{2 The} concentration ranges from 4.0% to 5.0% by weight. Preferred silicates include potassium metasilicate, potassium silicate, sodium metasilicate, sodium silicate and the like.

The amount of propylene glycol added to the developer of the present invention is 0.1% by weight to 20% by weight, preferably 1% by weight to 10% by weight. The water content is 70% by weight or more, preferably 85% by weight or more.

The developer of the present invention has a high pH, particularly preferably used at pH 12 to 13.5, and more preferably at pH 12.5 to 13.0.
It is.

The developing solution of the present invention substantially comprises a silicate, propylene glycol and water, but may contain an organic solvent or a surfactant as usually added to the developing solution within a safe range.

The photosensitive layer used in the present invention preferably contains a high-molecular polymer, particularly preferably contains a high-molecular polymer having an acid value of 10 to 300, and as the polymer,
For example, acrylic acid or methacrylic acid copolymer, crotonic acid copolymer, itaconic acid copolymer, maleic acid copolymer, a cellulose derivative having a carboxyl group in a side chain, a polyvinyl alcohol derivative having a carboxyl group in a side chain, Examples thereof include a hydroxyalkyl acrylate or methacrylate copolymer having a carboxyl group in a side chain, and an unsaturated polyester resin having a carboxyl group in a side chain.

Among these, preferred are copolymers having a phenolic hydroxyl group in the side chain described in JP-A-55-155355 and side-chains described in JP-A-50-118802. In particular, a copolymer having an alcoholic hydroxyl group, particularly a polymer having an alcoholic hydroxyl group is preferably used in view of dyeability and adhesiveness.

Examples of the alcoholic hydroxyl group-containing polymer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N- (4-hydroxyethylphenyl) methacrylamide, and hydroxymethyldiacetone (meth) acrylamide.

The polymer used as the resin binder according to the present invention can obtain favorable results when the acid value is in the range of 10 to 300. That is, in order to impart alkali developability to an aqueous developer, it is preferable to use a binder resin having an acid value in the range of 10 to 300, whereby a high developing speed and a good image can be obtained.

Therefore, when the acid value is less than 10, the developing speed is insufficient, and when the acid value is more than 300, the film is weak against over-developing.

The photosensitive layer suitable for the developer of the present invention includes a diazo compound,
Photopolymerizable compounds, photocrosslinkable compounds and the like are used. Preferably, a diazo resin is used.

The photosensitive layer used in the present invention includes various types of diazo resins, and is preferably a diazo resin represented by a condensate of p-diazodiphenylamine and formaldehyde, and is water-insoluble and organic solvent-soluble. Things
Preferably, those which are insoluble in water and soluble in ordinary organic solvents as described in JP-B-47-1167 and JP-B-57-43890 are used. Particularly preferred is a diazo resin represented by the following general formula [I].

General formula [I] [Wherein R ¹ , R ² and R ³ represent a hydrogen atom, an alkyl group or an alkoxy group, and R ⁴ represents a hydrogen atom, an alkyl group or a phenyl group.

X represents a PF ₆ or BF _4, Y is -NH -, - S- or -O
Indicates-. As the diazo monomer in the diazo resin used in the present invention, for example, 4-diazo-diphenylamine,
1-diazo-4-N, N-dimethylaminobenzene, 1-
Diazo-4-N, N-diethylaminobenzene, 1-diazo-4-N-ethyl-N-hydroxyethylaminobenzene, 1-diazo-4-N-methyl-N-hydroxyethylaminobenzene, 1-diazo-2 , 5-diethoxy-
4-benzoylaminobenzene, 1-diazo-4-N-
Benzylaminobenzene, 1-diazo-4-N, N-dimethylaminobenzene, 1-diazo-4-monophorinobenzene, 1-diazo-2,5-dimethoxy-4-p-tolylmercaptobenzene, 1-diazo -2-ethoxy-4-
N, N-dimethylaminobenzene, p-diazo-dimethylanilone, 1-diazo-2,5-dibutoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-morpholinobenzene, 1-diazo- 2,5-dimethoxy-4
Morpholinobenzene, 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzene, 1-diazo-4
-N-ethyl-N-hydroxyethylaminobenzene,
1-diazo-3-ethoxy-4-N-methyl-N-benzylaminobenzene, 1-diazo-3-chloro-4-N,
N-diethylaminobenzene, 1-diazo-3-methyl-4-pyrrolidinobenzene, 1-diazo-2-chloro-
4-N, N-dimethylamino-5-methoxybenzene, 1
-Diazo-3-methoxy-4-pyrrolidinobenzene, 3
-Methoxy-4-diazophenylamine, 3-ethoxy-4-diazodiphenylamine, 3- (n-propoxy) -4-diazodiphenylamine, 3- (isopropoxy) -4-diazodiphenylamine and the like.

As the aldehyde used as a condensing agent with the diazo monomer, for example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde,
Isobutyraldehyde, benzaldehyde and the like can be mentioned.

Further, as the anion, a water-soluble diazo resin can be obtained by using a chloride ion, tetrachlorozinc acid or the like, and boron tetrafluoride, phosphorous hexafluoride, triisopropylnaphthalenesulfonic acid, 4,4 ′ -Biphenyldisulfonic acid, 2,5-dimethylbenzenesulfonic acid, 2
By using -nitrobenzenesulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, or the like, an organic solvent-soluble diazo resin can be obtained. Particularly preferably, a diazo resin composed of hexafluorophosphoric acid is used.

The diazo resin is preferably used in combination with a film-forming resin, particularly a polymer compound having a hydroxyl group. Particularly preferably, the polymer compound includes a monomer having an aliphatic hydroxyl group in a side chain, for example, a copolymer of 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate with another copolymerizable monomer.

In addition to these, a polyvinyl butyral resin, a polyurethane resin, a polyamide resin, an epoxy resin, a novolak resin, a natural resin, and the like may be added as necessary.

As the binder used in combination with the diazonium salt, various polymer compounds can be used.
Monomers having an aromatic hydroxyl group as described in JP-A-54-98613, for example, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl)
Copolymers of methacrylamide, o-, m-, or p-hydroxystyrene, o-, m-, or p-hydroxyphenyl methacrylate with other monomers, U.S. Pat.
Polymers containing a hydroxyethyl acrylate unit or a hydroxyethyl methacrylate unit as a main repeating unit as described in 123,276 are exemplified.

In addition to these polymers, if necessary, polyvinyl butyral resin, polyurethane resin, polyamide resin, epoxy resin, novolak resin, shellac, rosin and other natural resins, polyvinyl alcohol, US Patent No. 3,751,25
No. 7, the polyamide resin described in U.S. Pat.No. 3,660,097, a linear polyurethane resin described in U.S. Pat.No. 3,660,097, a phthalated resin of polyvinyl alcohol, an epoxy resin condensed from bisphenol A and epichlorohydrin, cellulose acetate, It contains celluloses such as cellulose acetate phthalate.

Examples of alkali-soluble resins include novolak resins, vinyl polymers having phenolic hydroxyl groups, and JP-A-55-57
And a condensation resin of a polyhydric phenol and an aldehyde or ketone described in JP-A-841. Novolak resins include, for example, phenol-formaldehyde resin, cresol-formaldehyde resin, and JP-A-55-57
Phenol / cresol / formaldehyde copolycondensation resin as described in JP 841
No. 53, a copolycondensation resin of p-substituted phenol and phenol or cresol and formaldehyde, and the like.

The diazo resin used in the present invention is used by being mixed with a binder resin.When the binder resin is taken as 100, the diazo resin has a good range of 20 to 200 parts by weight, preferably 50 to 150 parts by weight. It is in the range of parts by weight.

To these photosensitive compositions, other dyes such as dyes and pigments, sensitizers, plasticizers, surfactants and the like can be added. These additives are used in an amount of 0.1% by weight to 20% by weight, preferably 0.5% by weight to 10% by weight, based on the solid content of the photosensitive layer.

Also as a photosensitive group on the polymer main chain or side chain And those containing a photosensitive polymer as a main component, such as polyesters, polyamides, and polycarbonates. For example, a photosensitive polyester obtained by condensation of phenylenediethyl acrylate with hydrogenated bisphenol A and triethylene glycol as described in JP-A-55-40415, U.S. Pat. No. 2,956,878
And (2-properidene) malonic acid compounds such as cinnamylidenemalonic acid and photosensitive polyesters derived from difunctional glycols.

Furthermore, a photopolymerizable composition comprising an addition-polymerizable unsaturated compound is also included.

Here, the unsaturated monomer includes alcohols (for example, ethanol, propanol, hexanol, octanol, cyclohexanol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, pentane Acrylic acid or methacrylic acid ester of erythritol, etc., amines (eg, methylamine, ethylamine, butylamine, benzylamine, ethylenediamine, diethylenetriamine, hexamethylenediamine, xylylenediamine, dimethylamine, diethylamine, ethanolamine, diethanolamine, aniline, etc.) ) With glycidyl acrylate or glycidyl methacrylate Adult.

Reaction products of carboxylic acids (eg, acetic acid, propionic acid, benzoic acid, acrylic acid, methacrylic acid, succinic acid, maleic acid, phthalic acid, tartaric acid, citric acid, etc.) with glycidyl acrylate or glycidyl methacrylate.

An amide derivative (for example, acrylamide, methacrylamide, N-methylolacrylamide, methylenebisacrylamide, etc.), a reaction product of an epoxy compound and acrylic acid or methacrylic acid, or the like can be used.

The following can be used as the photopolymerization initiator.

Benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy-α-phenylacetophenone, benzophenone, 2,4-
Dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone,
Benzophenone derivatives such as 4,4'-bis (diethylamino) benzophenone, 2-chlorothioxanthone,
Thioxanthone derivatives such as isopropylthioxanthone, anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, α,
α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, halogen compounds and the like.

In addition, a binder is preferably added to the photopolymerizable composition. As the binder, those used together with the diazo resin can be used, and more preferably, a photocrosslinkable copolymer having an ethylenically unsaturated bond in a side chain described in JP-B-49-17874 is used. You.

In addition to the above, a dye for visualizing an image after exposure or development, for example, Victoria Pure Blue
Photo-sensitive diazo compounds such as triphenylmethane-based and diphenylmethane-based dyes such as BOH (made by Hodogaya Chemical) and Oil Blue ^# 603 (made by Orient Chemical Industries), etc. Compounds, o-naphthoquinonediazide compounds, aromatic compounds having a trihalomethyl group, such as oxadiazole compounds having a trihalomethyl group or s-triazine compounds having a trihalomethyl group (for example, see JP-A-62-112162). Gazettes and references).

Further, in the photosensitive layer, alkyl ethers (for example, ethylcellulose, methylcellulose, etc.) for improving coating properties, fluorine surfactants, nonionic surfactants (for example, Pluronic L64 (manufactured by Asahi Denka Co., Ltd.), etc.), A plasticizer (for example, polyethylene glycol, tricresyl phosphate, acrylic acid or methacrylic acid polymer, etc.) and a stabilizer (for example, phosphoric acid, etc.) for imparting flexibility of the membrane can be contained.

As the silicone rubber used in the present invention, a linear organic polymer having a repeating unit represented by the following general formula [I] and having a hydroxyl group in the main chain or at the terminal of the main chain having a molecular weight of thousands to hundreds of thousands is preferred. Those containing siloxane as a main component are preferred.

General formula [I] 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, an alkoxyl group, a vinyl group, an aryl group, or a silanol group (OH group).
Those in which 60% or more are methyl groups are preferred. The silanol group (OH group) may be in the main chain or at the terminal of the main chain, but is preferably at the terminal.

As the silane coupling agent (or silicone crosslinking agent) used in the present invention, R _n SiX _4-n (where n is an integer of 1 to 3, and R is alkyl, aryl, alkenyl or a combination thereof) representing a monovalent group, and these groups are halogen, amine, hydroxy, alkoxy, aryloxy, optionally .X have a functional group of the thiol such as -OH, -OR ^2, -OAc, Represents a substituent such as -Cl, -Br, -I. Here, R ² and R ³ represent the same as R described above, and R ² and R ³ may be the same or different. Ac represents an acetyl group. )
Is a silane compound represented by

That is, the silicone rubber useful in the present invention is obtained by a condensation reaction of such a silicone base polymer with the above-mentioned silicone crosslinking agent.

Specific examples of the silane coupling agent used in the present _{invention, HN [(CH 2) 3} Si (OMe) 3] 2, _{vinyltriethoxysilane, Cl (CH 2) 3 Si} (OMe) 3, CH 3 Si (OAc) ₃ , HS
(CH ₂ ) ₃ Si (OMe) ₃ , vinyltris (methylethylketoxime) silane and the like.

The silicone rubber is also available as a commercial product, for example, YE-3085 manufactured by Toshiba Silicone Co., Ltd. Another useful silicone rubber is a reaction of the base polymer as described above with a silicone oil having a repeating unit represented by the following general formula [II], or 3% of R
It can also be obtained by an addition reaction of a silicone having a vinyl group with a base polymer or a reaction between the silicone oils.

General formula [II] (In the formula, R has the same meaning as R which is a substituent of the polymer represented by the general formula [I], m is an integer of 2 or more, and n is 0 or an integer of 1 or more.) Such a crosslinking reaction In order to obtain a silicone rubber, a crosslinking reaction is carried out using a catalyst. This catalyst includes tin, zinc, cobalt, lead, calcium, manganese,
Organic carboxylate salts of metals such as dibutyltin laurate, tin (II) octoate, cobalt naphthenate, and chloroauric acid are used.

In order to improve the strength of silicone rubber and obtain silicone rubber that can withstand the frictional force generated during printing work,
Fillers can also be mixed. Silicone rubber premixed with a 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 is used.
Alternatively, a disversion of LTV silicone rubber is preferably used. Such examples include silicone rubber disversions for paper coating such as Syl Off 23, SRX-257, SH237 manufactured by Toray Silicone.

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

It is preferable that the silicone rubber layer contains a silane coupling agent having an amino group in order to further improve the adhesiveness.

Preferred silane coupling agents include, for example, the following.

(A) H ₂ NCH ₂ CH ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₃ (b) H ₂ NCE ₂ CH ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₂ (CH ₃ ) (c) H ₂ N (CH ₂ ) ₃ Si (OEt) ₃ The silicone rubber layer used in the present invention may further contain a small amount of a photosensitizer.

The silicone rubber layer used in the present invention is obtained by dissolving the silicone rubber in a suitable solvent, and then coating and drying the photosensitive layer.

The support of the present invention is preferably a material that can be set in a normal lithographic printing machine and withstands a load applied during printing, such as aluminum, zinc, copper, a metal plate such as steel, and chromium, zinc, and the like. Copper, nickel, aluminum and iron plated or evaporated metal plate, paper,
Examples thereof include plastic films and glass plates, resin-coated paper, and paper on which metal foil such as aluminum is stretched.

 Of these, an aluminum plate is preferred.

The treatment on the support itself for improving the adhesion is not particularly limited, and includes various surface roughening treatments and the like.

The support may have a primer layer, and the primer layer includes, for example, a polyester resin, a vinyl chloride-vinyl acetate copolymer, an acrylic resin, a vinyl chloride resin, a polyamide resin, a polyvinyl butyral resin, an epoxy resin, and an acrylate. Copolymer, vinyl acetate copolymer,
Phenoxy resin, polyurethane resin, polycarbonate resin, polyacrylonitrile butadiene, polyvinyl acetate and the like can be mentioned. To these primer layers, a compound capable of generating an acid upon exposure and a dye capable of discoloring or fading due to the acid can be added.

Further, as the anchor agent constituting the primer layer, for example, the above-mentioned silane coupling agent, silicone primer and the like can be used, and organic titanate is also effective.

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

In the present invention, a protective layer may be provided on the upper surface of the silicone rubber layer, if necessary.

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. 8 g of ammonium hexafluorophosphate was dissolved in this solution, and a cold concentrated aqueous solution was added. The resulting precipitate was collected by filtration, 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 is immersed in a 3% aqueous sodium hydroxide solution and washed with water, and then anodized in a 32% aqueous sulfuric acid solution at 30 ° C. and 5 A / dm ² for 10 seconds. The plate was washed with water, immersed in a 2% sodium metasilicate aqueous solution at a temperature of 85 ° C. for 37 seconds, further immersed in water (pH 8.5) at a temperature of 90 ° C. for 25 seconds, washed with water and dried to obtain an aluminum plate a.

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. It was further dried at 100 ° C. for 4 minutes to form a 0.8 μm thick primer layer.

Primer layer composition (1) diazo resin-18 parts (2) 2-hydroxyethyl methacrylate, methyl methacrylate copolymer resin with a molar ratio of 34/64-82 parts (3) HPC LP (Shin-Etsu Chemical Co., Ltd.) (4) Methyl cellosolve 900 parts Next, a photosensitive composition having the following composition was applied on the primer layer, and dried at 100 ° C. for 2 minutes to obtain a photosensitive layer having a thickness of 0.3 μm. Was formed.

(Photosensitive composition) (1) 50 parts of diazo resin-1 (2) 2-hydroxyethyl methacrylate, N- (4
-Hydroxyphenyl) methacrylamide, methacrylic acid Resin having a molar ratio of 40/57/3-150 parts (3) Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd., dye) 1 part (4) Methyl cellosolve 900 Next, the following silicone rubber composition was applied on the above-mentioned photosensitive layer so as to have a dry weight of 1.8 g / m ² , and dried at 90 ° C. for 10 minutes.

(Silicone rubber layer composition) (1) Dimethylpolysiloxane having hydroxyl groups at both ends (molecular weight 82,000) 100 parts (2) Triacetoxymethylsilane 10 parts (3) Dibutyltin laurate 0.8 parts (4) Isopar E (Esso Chemical) Next, a 5 μm-thick, single-sided matted polypropylene film was laminated on the silicone rubber layer to obtain a waterless planographic plate.

After the positive film was brought into close contact with the upper surface of the plate material in vacuum, exposure was performed using a metal halide lamp as a light source. Next, 30 parts of the following developer 1 were charged in the automatic developing machine shown in FIG. 1, and the silicone rubber layer and the photosensitive layer in the unexposed portions were removed by rubbing with a brush of a developing section.

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. As a result, a printing plate in which halftone dots were well reproduced up to 2 to 98% and the silicone rubber layer was not damaged was obtained.

(Developer-1) Propylene glycol 6.0 parts Potassium metasilicate 8.0 parts Water 86.0 parts (Staining solution) Solfit (Kuraray Isoprene Chemical Co., Ltd.) 10 parts Leodol TW-0120 (Kao Corporation, surfactant) 0.5 parts Benzyl alcohol 2.5 parts Victoria Pure Blue BOH 0.5 parts Water 100 parts In addition, even if the operation is stopped for 5 days, only a few white crystals are found on the brush of the developing section. When removed, it was easily removed. No scratch was seen on the silicone rubber layer of the treated printing plate.

Comparative Example-1 A test was performed in the same manner as in Example 1 except that propylene glycol was removed from Developer-1 used in Example-1, and the silicone rubber layer was scratched by a brush.
It appeared as stain when dyeing. Halftone reproducibility is 3 ~
97%.

When the operation was stopped for 5 days, white crystals adhered to the brush in the developing section of the automatic developing machine.

When development processing was performed in this state, the silicone rubber layer had deeper and more flaws, adhered more, and had ink on the flawed portions during printing, resulting in a very dirty printed matter.

Example 2 Production of Positive PS Plate A 0.24 mm-thick JIS-1050 aluminum plate was immersed in a 2% aqueous sodium hydroxide solution, degreased, and then electrochemically treated in a dilute nitric acid solution. After roughening and washing well, anodizing treatment was performed in a dilute sulfuric acid solution to form an oxide film of 2.5 g / m ² on the surface of the aluminum plate. The thus treated aluminum plate was washed with water, dried, coated with a photosensitive solution having the following composition so as to have a dry weight of 2.5 g / m ^2, and dried to obtain a positive PS plate.

[Composition of photosensitive coating solution] An ester compound of naphthoquinone- (1,2) -diazide- (2) -5-sulfonic acid chloride and pyrogallol-acetone resin (described in Synthesis Example 2 of JP-A-60-143345) 2 parts by weight Copolymer resin of phenol, m-, p-mixed cresol and formaldehyde (molar ratio of each of phenol, m-cresol and p-cresol at the time of synthesis was 20: 48: 3)
2, weight average molecular weight Mw = 7400, number average molecular weight Mw = 1400)
6.5 parts by weight Novolak resin synthesized from p-tert-octylphenol and formaldehyde and naphthoquinone- (1,2)-
Ester compound with diazide- (2) -5-sulfonic acid chloride (condensation ratio: 50 mol%, Mw = 1700) 0.1 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.08 parts by weight Ethyl cellosolve 80 parts by weight Methyl cellosolve 20 parts by weight Preparation of a waterless lithographic plate Synthesis of diazo resin 14.5 g of p-diazodiphenylamine sulfate was added under ice cooling to 4 g
Dissolved in 0.9 g of concentrated sulfuric acid. To this reaction solution, 1.0 g of paraformaldehyde was slowly added so that the reaction temperature did not exceed 10 ° C.

Thereafter, stirring was continued for 2 hours under ice cooling. 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 is
Was dissolved in 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 collected by filtration, washed with water, and dried at 30 ° C. overnight to obtain diazo resin-1.

The coupling product with β-naphthol was measured by the GPC method. Styrene-equivalent weight average molecular weight (M
w) was 1500 and the number average molecular weight was 500.

Synthesis of polymer 150 g of 2-hydroxyethyl methacrylate, 60 g of acrylonitrile, 79.5 g of methyl methacrylate, and 10.0 of methacrylic acid (each molar ratio is 37: 35: 24: 4) are dissolved in 700 g of distilled dioxane (total monomer concentration: 4.5 mol /
) 15 g (2 mol%) of benzoyl peroxide was gradually added, and a polymerization reaction was carried out for 8 hours under a reflux state in a nitrogen stream. After completion of the reaction, 0.5 g of hydroquinone was added, the solvent was distilled off under reduced pressure, and when the viscosity increased, the mixture was poured on a stainless steel plate and vacuum dried to obtain 270 g of a plate-like resin (polymer 1). The GPC measurement of the polymer is shown below.

Mw: 4.80 × 10 ⁴ , dispersion ratio: 2.2 Anodizing was performed on the degreased and washed aluminum plate in a 40% by weight sulfuric acid aqueous solution at a temperature of 30 ° C. and a current density of 1.5 A / dm ² for 2 minutes. A sodium silicate treatment was performed at 85 ° C. for 25 seconds in an aqueous solution of sodium silicate by weight, followed by washing with water to obtain a substrate.

A primer layer composition having the following composition was applied to the substrate at 5.5 ° C. using a whitener and dried at 85 ° C. for 3 minutes to provide a primer layer. The dry film thickness was 10 mg / dm ² .

Primer layer composition Polymer (alcoholic hydroxyl group-containing polymer) 100 parts by weight Diazo resin (p-diazodiphenylamine / formaldehyde resin) 20 parts by weight Methyl cellosolve 2400 parts by weight Next, a 3 KW ultra-high pressure mercury lamp is applied to an aluminum plate coated with the above composition. To perform 100 mJ / cm ² overall exposure. The aluminum plate coated with the primer layer obtained in this manner did not dissolve even when immersed in a solvent for coating the photosensitive layer (methyl cellosolve) or a developing solution.

The UV integrating sphere was measured with a Hitachi spectrometer 3200, and the decomposition ratio of diazo was measured. As a result, it was found that the diazo absorption portion at 378 nm was completely decomposed by the exposure.

The primer layer coated aluminum plate, so that the 3 mg / dm ² The following photosensitive composition by dry weight, 55
It was then applied with a whiter at ℃ and dried to form a photosensitive layer.

[Photosensitive composition] 100 parts by weight of polymer (alcoholic hydroxyl group-containing polymer) 10 parts by weight of diazo resin (p-diazodiphenylamine / formaldehyde resin) 2 parts by weight of Victoria Blue BOH 2000 parts by weight of methyl cellosolve 1000 parts by weight of ethyl cellosolve A silicone rubber layer was provided on the above-mentioned photosensitive layer by applying a silicone rubber composition at a temperature of 55 ° C. to a dry weight of 15 mg / dm ² at 55 ° C. and drying.

[Silicone Rubber Composition] Toshiba Silicone YF-3057 100 parts by weight Toshiba Silicone TSL-8180 10 parts by weight Aerosil R-972 (Nippon Aerosil Co., Ltd.) 3 parts by weight Di-n-butyltin dilaurate 0.8 parts by weight Hexane 1400 5 parts by weight A single-sided matte polypropylene film having a thickness of 5 μm was laminated on the surface of the obtained silicone rubber layer to obtain a waterless photosensitive lithographic printing plate.

[Developer-2] Propylene glycol 10 parts by weight Emulgen 147 (nonionic activator manufactured by Kao Corporation) 0.1 part by weight Potassium silicate aqueous solution (SiO ₂ : 26% by weight, K ₂ O: 14% by weight) 18 parts by weight Potassium hydroxide 4 parts by weight Water 70 parts by weight A positive film was superimposed on the positive PS plate and the waterless planographic plate and exposed with a 3KW metal halide lamp from a distance of 70 cm for 50 seconds. Further, the lithographic plate without water peeled off the laminate film after exposure.

Next, the exposed PS plate and waterless lithographic plate were developed in the developing tank shown in FIG.

The developer 2 was placed in the developing tank 1 and the temperature was adjusted to 30 ° C.

The processing time was 20 seconds for the positive PS plate and 60 seconds for the waterless planographic plate. Each of the developed plates was printed on a dedicated printing machine, and the lithographic plate without water gave good prints without damage to the silicone rubber layer and no stains.The positive PS plate also gave good prints without stains. Obtained.

[Effect of the Invention] In the present invention, since the aqueous developer containing silicate and propylene glycol is used, the silicone rubber layer is hardly damaged by the brush during development, and silicate crystals adhere to the brush. There is an effect that it is difficult to do.

Further, there is provided a waterless photosensitive lithographic printing plate developer capable of obtaining a lithographic printing plate excellent in dot reproducibility.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an automatic developing machine using the developing solution of the present invention. Main code number 1 Developing tank 2, 3 Roller 4 Brush 5 Shower 6 Pump 7 Temperature control heater

Continuation of the front page (56) References JP-A-60-28654 (JP, A) JP-A-63-317379 (JP, A) JP-A 1-214839 (JP, A) JP-A-3-122644 (JP) JP-A-60-133452 (JP, A) JP-A-3-148665 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/00, 7/32

Claims (1)

(57) [Claims] 1. A developer for a waterless photosensitive lithographic printing plate having a primer layer, a photocurable photosensitive layer and a silicone rubber layer on a support in order, wherein the developer contains silicate, propylene glycol and water. A developer for a water-free photosensitive lithographic printing plate, characterized by comprising: