JPH08325500A - Waterless plate ink composition - Google Patents

Abstract

PURPOSE: To efficiently plasticize a waterless-form plate to thereby improve its resistance to abrasion on the press by incorporating a specific compd. into a waterless plate ink compsn. CONSTITUTION: This ink compsn. contains at least one hardly water-sol. compd. having a water-solubility lower than 10% at 20 deg.C (e.g. diethylene glycol mono-2- ethylhexyl ether) and at least one hydrotropic agent which is a salt of a hard acid-soft base type or a soft acid-hard base type and is generally an electrolyte comprising an inorg. ion and an org. ion (e.g. p-ethylbenzenesulfonic acid). The compsn. can be used for a sheet-feed press ink, a rotary offset ink, an ultraviolet-curable ink, and an electron-beam-curable ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterless lithographic ink composition which is preferably used when printing a waterless lithographic plate.

[0002]

2. Description of the Related Art Conventionally, various printing plates have been proposed for using a silicone rubber layer as an ink repellent layer and performing lithographic printing without using fountain solution.

For example, as a positive-working photosensitive lithographic plate, there is no water in which a photopolymerizable photosensitive layer and a silicone rubber layer are laminated on a substrate as disclosed in JP-B-54-26923 and JP-B-56-23150. Lithography, and special fair 3-
In Japanese Patent No. 56622 and Japanese Patent Laid-Open No. 61-153655, there are proposed waterless planographic printing plates in which a photocrosslinkable photosensitive layer and a silicone rubber layer are laminated on a substrate.

Further, as a negative photosensitive lithographic plate, Japanese Patent Publication No.
1-616 and JP-B-61-54218, a waterless planographic printing plate in which a photosensitive layer containing an orthoquinonediazide compound is provided on a support and a silicone rubber layer is provided thereon via an adhesive layer, JP-B-61- In Japanese Patent No. 54222 and the like, a waterless planographic printing plate in which a silicone rubber layer is provided on a photoreleasable photosensitive layer has been proposed, and it is known to have excellent performance in practice.

However, in these waterless planographic printing plates, when the number of printed sheets is large, the silicone rubber layer in the non-image area drops off like a pinhole, and the ink adheres to that area, resulting in a defect on the printed matter. there were. Further, in recent years, waterless planographic printing by an offset rotary printing machine has been put into practical use. Compared with sheet-fed printing presses that have traditionally used waterless planographic printing presses, the offset rotary printing press has 3 to 6 times the number of rotations and the number of printed sheets at the time of printing. Printability is required. The printing durability referred to here is the resistance against the occurrence of the above-mentioned defects of the non-image area during printing.

Various studies have been made for the purpose of improving these printing durability. The method of increasing the thickness of the silicone rubber layer is not suitable for practical use because the developability is remarkably deteriorated and the processing speed is greatly reduced when developing with an automatic processor or the like.

Further, there has been proposed a method for improving printing durability by increasing the coating strength of the silicone rubber layer. Specifically, JP-A-49-86103 and JP-A-5-86103
5-110249 and the like, various silane coupling agents, JP-A-54-54702 and the like, vinyltriacyloxysilane, JP-A-58-58
In the 60744 publication, etc., an organic titanium compound is
Japanese Patent Application Laid-Open No. 2-62543 proposes a method of adding a fluorine-based cross-linking agent to increase the film strength of the silicone rubber layer. When the above-mentioned various additives are added, the coating strength of the silicone rubber layer is increased, the scratches on the silicone rubber layer are lightened, and the printing durability is improved, but the developability is remarkably reduced when the development processing is carried out by an automatic processor or the like. Or
It has not been put to practical use due to the drawback that the development processing speed is greatly reduced.

As another method, there has been proposed a method in which the photosensitive layer and the primer layer under the silicone rubber layer are softened to relieve the stress repeatedly applied to the surface of the silicone rubber layer during printing. As a method of softening the primer layer, in JP-A-5-53306 and JP-A-5-53307, a natural protein and a urethane elastomer, or a polyurethane and a silane coupling agent are contained between the substrate and the photosensitive layer. Therefore, a method for softening the primer layer has been proposed.
In Japanese Patent Laid-Open No. 57-57, the softening is attempted by including a plasticizer in the primer layer. Further, as a method of softening the photosensitive layer, a photosensitive layer containing a plasticizer is proposed in JP-A-3-68946 and the like. Although the printing durability was greatly improved by the method of softening the primer layer or the photosensitive layer as described above, when the plate surface was rubbed and developed by a brush with an automatic processor, the stress of the brush rub was diffused. However, there has been a problem that the developability is lowered and the development processing speed is greatly lowered, so that it has not been put into practical use. As described above, it is understood that there is a problem in the method of softening the waterless lithographic plate before development.

On the other hand, in JP-A-6-214403, JP-A-6-337523, JP-A-7-56326, etc., when a waterless lithographic plate is subjected to development processing after exposure using an automatic developing machine or the like, A method has been proposed in which the silicone rubber layer is removed to form the image area, and then a compound capable of imparting flexibility to the waterless planographic photosensitive layer and the silicone rubber layer is permeated or swollen. By this method, the problems of the decrease in developability and the decrease in processing speed in an automatic processor described above were avoided, and a waterless planographic plate having a flexible photosensitive layer and a silicone rubber layer could be obtained. However, this method has the effect of softening the waterless lithographic plate immediately after the start of printing, but the organic solvent in the ink penetrates into the silicone rubber layer during printing and the compound that imparts flexibility is extracted. However, the flexibility was lowered, and as a result, the improvement of printing durability was insufficient.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a waterless lithographic ink composition which overcomes the above-mentioned drawbacks of the prior art and improves the printing durability of the waterless lithographic plate.

[0011]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the object of the present invention is achieved by an ink composition for a waterless lithographic plate containing at least one poorly water-soluble compound and at least one hydrotrope agent.

In the present invention, the waterless lithographic plate is subjected to post-exposure development treatment and, if necessary, further dyeing treatment,
At least one water-insoluble compound and hydrotrope agent
Printing is carried out with a waterless lithographic ink composition containing species by species. Therefore, the poorly water-soluble compound and the hydrotrope efficiently plasticize the waterless planographic printing plate, thereby improving the printing durability without impairing the development processing ability. The contents of the present invention will be described in detail below.

The poorly water-soluble compound of the present invention is an organic solvent having a solubility in water at 20 ° C. of less than 10%, and specific examples thereof include diisobutyl ketone, acetophenone,
Isophorone, diethyl succinate, methyl benzoate, diethyl oxalate, dimethyl phthalate, isobutyl acetate, benzyl benzoate, ethylene glycol monophenyl ether, ethylene glycol dibutyl ether, ethylene glycol benzyl ether, diethylene glycol monohexyl ether, diethylene glycol mono-2-ethylhexyl ether. Ether, diethylene glycol dibutyl ether, dimethylbenzyl carbitol, diethylene glycol diacetate, 2-ethylhexyl alcohol, benzyl alcohol, cyclohexanol, 1,3
-Octanediol, cyclohexanone, N-benzylethanolamine, anisyl alcohol, 2-N-ethylanilinoethanol, N-phenylethanolamine, triacetin, tributine, propylene glycol monophenyl ether, but are not limited thereto. Not a thing. Among these, ethylene glycol monophenyl ether, diethylene glycol monohexyl ether, benzyl alcohol, 1,3-octanediol, cyclohexanone, N-phenylethanolamine, triacetin, and propylene glycol monophenyl ether are preferable.

The hydrotrope agent used in the present invention is a salt of hard acid-soft base or soft acid-hard base type, and is generally a kind of electrolyte composed of inorganic ions and organic ions. For hard and soft acids and bases, see A. Scoot's Survey of Progress in Chemis.
try "(51-52 (1969) Academic Press Co.). Examples of compounds effective as such hydrotropes include compounds represented by the following general formulas (1) to (7).

[0015]

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[Chemical 4]

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[Chemical 6]

[Chemical 7] (In the formula, R _{1 to} R ₃ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms (including linear and branched ones), a hydroxyalkyl group having 1 to 4 carbon atoms, and hydroxyl group. group, a halogen atom (e.g. a chlorine atom, a bromine atom), a mercapto group, -SO ₃ M ₄ or -COO
Shows the M _5. R _{4 to} R ₁₁ each independently have 1 to 1 carbon atoms
2 alkyl groups (including linear, branched and cyclic ones), hydroxyalkyl groups having 1 to 4 carbon atoms, benzyl groups, or substituted (eg, alkyl groups having 1 to 4 carbon atoms such as a methyl group, Hydroxyl, halogen, etc.) or an unsubstituted phenyl group. R _{12 to} R ₁₆ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms (including linear and branched ones), a hydroxyl group, and —SO ₃
M6 represents a hydroxyalkyl group having 1 to ₆ carbon atoms. R ₁₇ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (including linear and branched ones), or a hydroxyalkyl group having 1 to 12 carbon atoms. M _{1 to} M ₆ are each a hydrogen atom, an alkali metal (Na, K, etc.) or N
Shows the H _4. Z represents N, P or B. X ₁ represents a counter ion, and when Z is N or P, an anion (for example,
Chlorine ion, bromine ion, iodine ion and other halogen ions, nitrate ion, sulfate ion, phosphate ion, hydroxide ion, PF ₆ ⁻ , BF ₄ ⁻ etc. are shown, and when Z is B, a cation (eg Li ⁺ , Na ⁺ , K ^+, etc., or NH ₄ ^+, etc., and X ₂ represents an anion (for example, examples as described above are included).
n shows the integer of 1-5. ) Specific examples of the compounds represented by the general formulas (1) to (7) used in the present invention include benzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, cumenesulfonic acid, benzoic acid, salicylic acid, and isophthalyl. Sulfonic acid,
Gallic acid, phenolsulfonic acid, thiosalicylic acid, tetraphenylphosphonium iodide, tetraphenylphosphonium bromide, tetraphenylphosphonium chloride, tetraphenylphosphonium sulfate, tetraphenylphosphonium nitrate, sodium tetraphenylboronium, tetra-n-butylphosphonium iodide, Tetra n-butylphosphonium bromide, tetra n-butylphosphonium chloride, tetra n-butylphosphonium sulfate, tetra n-butylphosphonium nitrate, tetrabutylammonium sulfate, tetrabutylammonium nitrate, ethyltriphenylphosphonium bromide, benzyltriphenylphosphonium Chloride, tetrabutylphosphonium hydroxide,
Tetrabutylphosphonium phosphate, ethyltriphenylphosphonium bromide, butyltriphenylphosphonium bromide, diphenylphosphonium chloride, benzyltriphenylphosphonium chloride, tetratolylphosphonium bromide, bis [(benzyl) (diphenyl) phosphorandiyl] ammonium chloride, 1 , 2-bis (diphenylphosphino) ethane bromide, 4- (butylphenyl) -2-hydroxybenzenesulfonic acid, 4- (butylphenyl) benzenesulfonic acid, diphenylethersulfonic acid and the like. In addition, these alkali metal salts (Na, K, Li
Salt), ammonium salt, butylisoquinolinium bromide, methylisoquinolinium chloride and the like. Particularly preferred hydrotropes used in the present invention include sodium p-toluenesulfonate, sodium metaxylenesulfonate, sodium p-ethylbenzenesulfonate, sodium cumenesulfonate, sodium naphthalenesulfonate, ammonium xylenesulfonate, and tetrabutyl. Examples thereof include, but are not limited to, ammonium bromide and the like. Among these, sodium p-toluenesulfonate, sodium metaxylenesulfonate, p-ethylbenzenesulfonic acid, and sodium naphthalenesulfonate are preferable.

The total content of the sparingly water-soluble compound and the hydrotrope agent in the ink composition is preferably 0.01 to 30% by weight, more preferably 0.05 to 20% by weight.

The weight ratio of the sparingly water-soluble compound to the hydrotrope agent is preferably 1: 9 to 9: 1, and more preferably 4: 6 to 6: 4.

It is essential that the ink composition of the present invention contains at least one poorly water-soluble compound and at least one hydrotrope agent, and other components are not particularly limited and those used in known ink compositions are used. it can.

Waterless planographic inks are roughly classified into sheet inks generally called oil-based inks, off-wheel inks, UV-curable inks which are cured by UV irradiation, and EB cure inks which are cured by electron beam irradiation. Can be used with any type of ink.

In the case of sheet-fed ink and off-wheel ink, the constituents of the ink composition vehicle used in the ink composition of the present invention include those used in known oil-based inks. Consists of resin, drying oil, solvent, molecular chain extender, etc.

Examples of the ink resin include petroleum resin, rosin, rosin ester, rosin-modified phenol resin, phenol resin, xylene resin, urethane resin, and alkyd resin.

The ink solvent is a petroleum solvent such as α-olefin solvent, paraffin solvent, isoparaffin solvent,
A naphthene type, an aromatic content paraffin type, etc. can be used.

As the drying oil, animal and vegetable oils having an iodine value of 130 or more can be used. For example, linseed oil, deer oil, eno oil, tung oil, dehydrated castor oil and the like and polymers thereof can be used. Drying oil has an iodine value of 10
As animal and vegetable oils of 0 to 130, for example, cottonseed oil, soybean oil, sesame oil, rapeseed oil and the like and polymers thereof can be used.

Further, a gelling agent such as an organic aluminum compound, an organic titanate compound, an organic zinc compound and an organic calcium compound may be added at the time of preparing the varnish.

Further, in order to adjust the stain resistance of such an ink, an amine compound having an active hydrogen in the molecule, a polyvalent carboxylic acid or its derivative, a resol type phenol resin, a polyhydric alcohol, or A molecular chain extender such as a mixture of these may be used.

A colorant and an additive are kneaded with the above-mentioned sheet-fed ink and off-wheel ink vehicle by a known method to prepare a waterless planographic ink.

As the colorant, those used in conventional ink compositions such as inorganic or organic pigments can be used.

As other additives, for example, wax, grease, desiccant, dispersant, filler, and other known additives can be used.

The preferred composition of the waterless lithographic sheet-fed ink that can be used in the present invention is as follows.

Resin 30 to 50 parts by weight Drying oil 10 to 30 parts by weight Solvent 30 to 50 parts by weight Water-insoluble compound 0.01 to 30 parts by weight Hydrotrope agent 0.01 to 30 parts by weight Stain resistance improver 0. 5 to 5 parts by weight Colorant 10 to 30 parts by weight Additive 0.5 to 10 parts by weight In addition, the following are listed as preferred compositions of the off-wheel ink for waterless lithographic plates that can be used in the present invention.

Resin 20 to 50 parts by weight Drying oil 5 to 20 parts by weight Solvent 30 to 50 parts by weight Water-insoluble compound 0.01 to 30 parts by weight Hydrotrope agent 0.01 to 30 parts by weight Stain resistance improver 0. 5 to 5 parts by weight Colorant 10 to 30 parts by weight Additive 0.5 to 10 parts by weight In the case of UV curable ink and EB cure ink, the composition of the vehicle for the ink composition used in the ink composition of the present invention. Examples of the components include those used in known UV-curable inks, and are composed of an ethylenically unsaturated compound, a photopolymerization initiator, a sensitizer, a polymerization inhibitor and the like.

The ethylenically unsaturated compound used in the present invention is at least one addition-polymerizable ethylenically unsaturated compound in the chemical structure of the molecule, and is a monomer, prepolymer, ie dimer, trimer. And tetramers and oligomers (meaning a polymer having a molecular weight of 10,000 or less or a polycondensate), a mixture thereof, and a copolymer having a low degree of polymerization thereof. Specific examples include pentaerythritol acrylate, pentaerythritol tetraacrylate, bisphenol A diglycidyl ether acrylate, polyacrylate carbamate, modified bisphenol A epoxy acrylate, adipic acid 1,
Prepolymers such as 6-hexanediol acrylic ester, phthalic anhydride propylene oxide acrylic ester, trimellitic acid diethylene glycol acrylic ester, rosin modified epoxy acrylate, and alkyd modified acrylate, and hydroxybutyl acrylate, dicyclopentadiene acrylate. ,
1,6-hexanediol monoacrylate, cyclohexyl acrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylol Examples thereof include monomers such as propane triacrylate, tripropylene glycol diacrylate, and pentaerythritol triacrylate, which can be used alone or in a mixture.

All known photopolymerization initiators can be used. Specific examples include anthraquinone, benzoin ether, benzyl, benzophenone, 4,4'-bisdimethylaminobenzophenone, 4,4'-bistrichloromethylbenzophenone, dibutylphenylphosphine, α, α-diethoxyacetophenone, 2-ethylanthra. Quinone, benzoin bisphenyl, chlorobenzophenone, benzoin, benzoin methyl ether,
Examples thereof include, but are not limited to, benzoin isobutyl ether, anthraquinone thioxanthone, methyl ossobenzoylbenzoic acid, and paradimethylaminoacetophenone.

Further, para-dimethylaminobenzoic acid ester or the like can be used as a sensitization aid.

Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, mono-t-butyl hydroquinone, catechol and picric acid.

A colorant and an additive are kneaded with the above ultraviolet curable ink and EB curing ink vehicle by a known method to prepare a waterless planographic ink.

As the colorant, those used in conventional ink compositions such as inorganic or organic pigments can be used.

Further, as other additives, for example, wax, grease, desiccant, dispersant, filler, and other known additives can be used.

The UV-curable waterless planographic ink composition used in the present invention preferably has the following composition.

Ethylenically unsaturated compound 50 to 80 parts by weight Water-insoluble compound 0.01 to 30 parts by weight Hydrotrope agent 0.01 to 30 parts by weight Photopolymerization initiator 2 to 20 parts by weight Colorant 10 to 30 parts by weight Others 0 to 20 parts by weight As the composition of the EB ink composition preferably used in the present invention, the following are preferably mentioned.

Ethylenically unsaturated compound 50 to 80 parts by weight Water-insoluble compound 0.01 to 30 parts by weight Hydrotrope agent 0.01 to 30 parts by weight Colorant 10 to 30 parts by weight Other additives 0 to 20 parts by weight Above In the ink composition of, when adding the poorly water-soluble compound and the hydrotrope agent, in the intermediate step of the production of the ink, a varnish is produced from the poorly water-soluble compound and the hydrotrope agent and other vehicle constituents, and then this varnish is added. Coloring agents, additives, etc. may be kneaded to form an ink, or alternatively, a sparingly water-soluble compound and a hydrotrope may be formed into an ink after the varnish is produced from the components that do not contain the sparingly water-soluble compound and the hydrotrope agent. Agents may be added. Further, the poorly water-soluble compound and the hydrotrope agent may be added to the ink prepared from the components other than the poorly water-soluble compound and the hydrotrope agent.

Next, a waterless planographic printing plate to which the present invention can be applied will be described.

The waterless planographic printing plate of the present invention preferably has at least a photosensitive layer, a silicone rubber layer and a protective layer on the substrate, and a primer is provided between the substrate and the photosensitive layer in order to improve adhesion to the substrate and prevent halation. Layers may be provided.

The structure of each layer will be described in detail below.

First, the substrate for the waterless planographic printing plate used in the present invention will be described.

The waterless planographic printing plate used in the present invention must be flexible enough to be set in an ordinary printing machine and capable of withstanding the load applied during printing. Therefore, as a typical substrate, a coated paper, a metal plate such as aluminum, a plastic film such as polyethylene terephthalate, rubber, or a combination thereof can be given. The surface of these substrates can be further coated with a primer layer or the like for the purpose of preventing halation and other purposes.

Regarding the primer layer, for example, Japanese Patent Laid-Open Publication No.
Various photosensitive polymers proposed in Japanese Unexamined Patent Publication No. 0-22903 are exposed and cured before laminating a photosensitive layer, and a methacrylic phosphorus-containing monomer proposed in JP-A-4-322181 is used as a photosensitive layer. Of the methacrylic epoxy compound proposed in Japanese Patent Laid-Open No. 7049/1990, which is exposed and cured before being laminated. Fifty
Heat-cured epoxy resin proposed in Japanese Patent Laid-Open No. 760, gelatin hardened in Japanese Patent Application Laid-Open No. 63-133151, Japanese Patent Laid-Open No. 1-28.
2270 and the one using a urethane resin proposed in JP-A-2-21072 can be cited. Other than this, a casein-hardened casein is also effective.

Further, for the purpose of imparting a film-forming ability to the primer layer, polyurethane, polyamide, styrene / butadiene rubber, carboxy-modified styrene / butadiene rubber having a glass transition temperature of room temperature or lower is added to the primer layer,
Polymers such as acrylonitrile / butadiene rubber, carboxy-modified acrylonitrile / butadiene rubber, polyisoprene rubber, acrylate rubber, polyethylene, chlorinated polyethylene, and chlorinated polypropylene may be added.

The film thickness of the primer layer used in the present invention is preferably in the range of 0.1 to 20 g / m ² in terms of dry weight, and is 1 to 10 g / m ² for the reasons of coatability, film forming property and economical reasons.
Is more preferable.

Next, the positive type photosensitive layer will be described.

The positive type photosensitive layer used in the present invention may have the following composition.

(1) Monomer or oligomer having at least one photopolymerizable ethylenically unsaturated double bond 3 to 50 parts by weight (2) Shape-retaining binder polymer 20 to 80 parts by weight (3) Light Sensitizer 0.2 to 20 parts by weight As a monomer or oligomer having a photopolymerizable ethylenically unsaturated double bond, a (meth) acrylic acid ester derived from a monohydric alcohol, a polyhydric alcohol (meth) Examples thereof include acrylic acid esters, epoxy acrylates obtained by reacting a glycidyl ether compound with (meth) acrylic acid, and urethane acrylates.

Any binder polymer can be used as long as it can be diluted with an organic solvent and has film-forming ability. Specific examples thereof include polyolefins, polystyrenes, acrylic ester polymers and methacrylic acid ester polymers and unvulcanized rubbers, polyoxides (polyethers), polyesters, polyurethanes, polyamides and the like as vinyl polymers.

As the photosensitizer, all known photosensitizers can be used. As a specific example, a benzophenone derivative,
Examples thereof include benzoin derivatives, quinones, thioxanthones and the like.

It is also useful to add a slight amount of a thermal polymerization inhibitor to the photosensitive layer for the purpose of improving the storage stability of the waterless planographic printing plate. Typical examples of such thermal polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, phenothiazine and the like.

Further, for the purpose of imparting shape-retaining property to the photosensitive layer, supporting the upper silicone rubber layer on a surface horizontal to the substrate surface, or improving the adhesiveness with the silicone rubber layer, organosilica may be added, if necessary. Alternatively, a silane coupling agent, a silylated monomer or an organometallic compound may be mixed in the photosensitive layer.

The film thickness of the photosensitive layer is preferably from 0.1 to 50 μm, more preferably from 0.5 to 10 μm for the reasons of coatability, film-forming property and economy.

Next, the negative photosensitive layer will be described.

The negative type photosensitive layer used in the present invention may have the following composition.

(1) Quinonediazide compound 50 to 100 parts by weight (2) Crosslinking agent 5 to 50 parts by weight (3) Binder polymer 5 to 100 parts by weight As a quinonediazide compound, JP-A-56-80046 is used.
A known quinonediazide compound as proposed in Japanese Patent Publication is mentioned.

As the cross-linking agent, polyfunctional isocyanates,
Polyfunctional epoxies and the like can be preferably used.

Examples of the binder polymer include vinyl polymers such as polyolefins, polystyrenes, acrylic acid ester polymers and methacrylic acid ester polymers and unvulcanized rubbers, polyoxides (polyethers), polyesters, polyurethanes and polyamides. To be

The film thickness of the photosensitive layer is preferably 0.1 to 50 μm, and more preferably 0.5 to 10 μm for the reasons of coatability, film-forming property and economy.

Next, the silicone rubber layer will be described.
The silicone rubber layer that can be used in the present invention preferably has a thickness of 0.5 to 50 μm, more preferably 0.5 to 10 μm in terms of developability and ink receptivity of halftone dot portions, and can transmit ultraviolet rays. It has transparency.

The silicone rubber layer is obtained by diluting a silicone rubber composition obtained by adding a cross-linking agent and a catalyst to polyorganosiloxane, if necessary, with a suitable solvent, coating the composition on the photosensitive layer, and heating and drying. It is formed by curing.

As the silicone rubber composition preferably used in the present invention, a wet heat curable condensation reaction crosslinkable silicone rubber composition and a heat curable addition reaction crosslinkable silicone rubber composition are preferably used.

The general form of the condensation reaction crosslinkable silicone rubber composition preferably used in the present invention is as follows.

(1) Polyorganosiloxane having a hydroxyl group at the terminal 100 parts by weight (2) Condensation reaction crosslinking agent 3 to 20 parts by weight (3) Condensation catalyst 0.01 to 0.05 parts by weight (4) Solvent 100 to 4000 Parts by Weight Next, a thermosetting addition reaction-crosslinking silicone rubber composition will be described.

The polyorganosiloxane used in the present invention means a polyvalent hydrogen polyorganosiloxane and a polyorganosiloxane having two or more --CH.dbd.CH-- groups in one molecule. After being melted to form a mixed solution, a catalyst, a curing retarder, etc. are added if necessary to obtain an uncured (unrubbed) silicone rubber composition.

The following are typical forms of the addition reaction-crosslinkable silicone rubber composition that is preferably used in the present invention.

(1) 100 parts by weight of organopolysiloxane having at least two alkenyl groups (more preferably vinyl groups) directly bonded to a silicon atom in one molecule (2) at least 2 SiH bonds in one molecule. Organohydrogenpolysiloxane having 0.1 to 10,000 parts by weight (3) Addition catalyst 0.00001 to 10 parts by weight (4) Solvent 100 to 4000 parts by weight Next, a method for producing a waterless planographic plate according to the present invention will be described. . After using a normal coater such as a slit die coater, a reverse roll coater, an air knife coater, and a Mayer bar coater on the substrate, if necessary, the primer layer composition is applied and cured at a temperature of 100 to 300 ° C. for several minutes, The photosensitive layer composition coating liquid is applied, dried at a temperature of 50 to 150 ° C. for several minutes, and thermally cured if necessary, and the silicone rubber layer composition is applied thereon, followed by heat treatment at a temperature of 50 to 150 ° C. for several minutes. Then, it is formed by curing the rubber.

Next, the cover film used in the present invention will be described. It is preferable that the cover film has ultraviolet transparency and a thickness of 50 μm or less, preferably 10 μm or less.

Specifically, known transparent plastic films such as polyethylene terephthalate, polyvinylidene chloride, polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, polyamide, polyurethane, cellophane, polyvinyl alcohol, polypropylene, polyethylene, polystyrene. A transparent plastic film such as cellulose acetate is preferably used.

Further, the transparent plastic film may be uniformly coated with a polymer containing silica particles or the like, or the polymer may be coated with a gravure roll or the like to form an uneven surface on the side in contact with the original film. It is preferable in terms of adhesion.

The waterless lithographic plate of the present invention thus produced is exposed to actinic rays through a vacuum-bonded original film. As the light source used in this exposure step, a high pressure mercury lamp, a carbon arc lamp, a xenon lamp, a fluorescent lamp or the like can be usually used.

The exposed waterless planographic plate is peeled off the protective film, immersed in a developing solution, and developed using a developing pad or a developing brush. In this case, the photosensitive resin layer in the image area and the silicone rubber layer thereon may be removed or only the silicone rubber layer may be removed, which can be controlled by the strength of the developing solution.

As the developing solution used in the present invention, those known as a developing solution for waterless lithographic plates can be used.
For example, aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (trade name of aliphatic hydrocarbons manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, Xylene or the like), halogenated hydrocarbon (tricrene or the like) to which a polar solvent is added, or the polar solvent itself is preferable.

Examples of polar solvents include alcohols, ketones, esters and the like.

Further, known basic dyes such as crystal violet, Victoria pure blue, and Astrazone red, acid dyes, and oil-soluble dyes can be added to the developer to dye the image area at the same time as the development.

When developing the waterless planographic printing plate used in the present invention, an automatic developing machine commercially available from Toray Co., Ltd. is used, and after the plate surface is pretreated with the above-mentioned developing solution, Rubbing on the surface of the rotary brush plate while showering tap water or the like enables suitable development. Further, instead of the above developing machine, the development can be performed by spraying hot water or steam on the plate surface.

The waterless planographic plate developed as described above is set in a printing machine for planographic printing and printed.

[0082]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The soil resistance in the examples is evaluated by the following method.

(1) Method for evaluating anti-smudge property The ink prepared in the ink composition described below has a room temperature of 25.
"Durrius" 700 in a room controlled at ℃
Attach the TAP (Toray Co., Ltd. positive type waterless planographic printing plate) to a printing machine (Davidson) so that the printing density of the ink is 1.5 with Macbeth density RD-514 (Macbeth) when using the red filter. Print on art paper while adjusting to. While printing under this fixed condition, the temperature of the plate surface is raised by the sheet heater attached to the plate cylinder, and the temperature at the time when scumming occurs on the non-image area on the paper surface is measured using the surface thermometer. To do. The background stain generation temperature is set to the ink background stain generation index CTI (Critical Ton).
ing Index) was used as an index of the resistance to ink smearing.

Example 1 <Varnish 1> Rosin-modified phenolic resin 42.0 parts by weight Polymerized linseed oil No. 4 15.0 parts by weight Linseed oil-modified alkyd resin 5.0 parts by weight No. 5 solvent (manufactured by Nippon Oil Co., Ltd.) 38.0 parts by weight <Varnish 2> Rosin-modified phenolic resin 45.0 parts by weight Polymerized linseed oil No. 4 17.0 parts by weight Aluminum octoate 1.5 parts by weight No. 5 solvent (manufactured by Nippon Oil Co., Ltd.) 36.5 Parts by weight The above mixture was heated to 185 ° C., and then stirred for 3 hours to perform cooking to obtain Varnish 1 and Varnish 2, respectively.

<Ink 1> Phthalocyanine blue 15.0 parts by weight Varnish 1 37.5 parts by weight Varnish 2 20.0 parts by weight Diethylene glycol mono-2-ethylhexyl ether 0.5 parts by weight p-ethylbenzene sulfonic acid 0.5 parts by weight Wax Compound 3.0 parts by weight Cobalt naphthenate (metal concentration 7.5%) 0.5 parts by weight Manganese naphthenate (metal concentration 6.5%) 0.5 parts by weight No. 5 solvent (manufactured by Nippon Oil Co., Ltd.) ) 5.0 parts by weight The above mixture was kneaded by passing through a three-roll three times to obtain a waterless planographic sheet-fed ink 1.

Example 2 <Varnish 3> Rosin-modified phenolic resin 38 parts by weight No. 7 linseed oil 12 parts by weight No. 3 solvent (manufactured by Nippon Oil Co., Ltd.) 46 parts by weight AT-50 (molecular chain extender, Toray Co., Ltd.) )) 4 parts by weight The above mixture was heated to 190 ° C. and stirred for 1 hour to prepare a varnish 3 by cooking.

<Ink 2> Varnish 3 74 parts by weight Phthalocyanine blue 17 parts by weight Wax 5 parts by weight Diethylene glycol monohexyl ether 0.5 parts by weight Sodium p-ethylbenzenesulfonate 0.5 parts by weight Dialen 168 (manufactured by Mitsubishi Chemical Corporation) 2 parts by weight The above mixture was kneaded by passing it through a three-roll mill three times to obtain an ink 2 for lithographic plate without off-wheel water.

Example 3 <Varnish 4> Acrylic resin (“Haridip” 116AM, manufactured by Harima Kasei Co., Ltd.) 240 parts by weight Rosin-modified epoxy acrylate (“Banbeam” 22C, manufactured by Harima Kasei Co., Ltd.) 470 parts by weight 1 , 9-Nonanediol diacrylate 290 parts by weight The above mixture was heated to 120 ° C. and stirred for 30 minutes, and varnish 4 was added.
I got

<Ink 3> Varnish 4 30 parts by weight “Aronix” 309 (acrylate compound manufactured by Toagosei Co., Ltd.) 5 parts by weight “Irgacure” 907 (α-aminoacetophenone manufactured by Ciba-Geigy) 2 parts by weight Triacetin 0.5 parts by weight Parts Sodium 4-metaxylene sulfonate 0.5 parts by weight Phthalocyanine blue 7.5 parts by weight Hydroquinone monomethyl ether 0.05 parts by weight The above mixture is kneaded with three rolls to obtain an ultraviolet curable waterless planographic ink 3. It was

Example 4 <Varnish 5> Acrylic resin (“High Dip” 116AM, manufactured by Harima Kasei Co., Ltd.) 240 parts by weight Rosin-modified epoxy acrylate (“Banbeam” 22C, manufactured by Harima Kasei Co., Ltd.) 470 parts by weight 1 , 9-Nonanediol diacrylate 290 parts by weight The above mixture was heated to 120 ° C. and stirred for 30 minutes, and varnish 5 was added.
I got

<Ink 4> Varnish 5 30 parts by weight “Aronix” 309 (acrylate monomer manufactured by Toagosei Co., Ltd.) 5 parts by weight Triacetin 0.5 parts by weight Sodium 4-metaxylene sulfonate 0.5 parts by weight Phthalocyanine blue 7 0.5 parts by weight Hydroquinone monomethyl ether 0.05 parts by weight The above mixture was kneaded with a three-roll mill to obtain a waterless planographic ink 4 of EB Cure.

Example 5 Web Zett N indigo (manufactured by Dainippon Ink Mfg. Co., Ltd.) 100 parts by weight Diethylene glycol monohexyl ether 0.5 parts by weight Sodium p-ethylbenzenesulfonate 0.5 parts by weight was added and kneaded well with an ink spatula. Then, Ink 5 was used.

Comparative Example 1 In the composition of Example 1, diethylene glycol mono 2-
Ink 6 was obtained in the same manner as in Example 1 except that only ethylhexyl ether and p-ethylbenzenesulfonic acid were removed.

Comparative Example 2 Ink 7 was prepared in the same manner as in Example 2 except that only diethylene glycol monohexyl ether and sodium p-ethylbenzenesulfonate were removed from the composition of Example 2.

Comparative Example 3 Ink 8 was obtained in the same manner as in Example 3 except that only triacetin and sodium 4-metaxylenesulfonate were removed from the composition of Example 3.

Comparative Example 4 Ink 9 was prepared in the same manner as in Example 4 except that only triacetin and sodium 4-metaxylenesulfonate were removed from the composition of Example 4.

Comparative Example 5 Web Zett N Ai (Dainippon Ink Mfg. Co., Ltd.)
Manufactured) was used as ink 10.

A printing test was conducted using a waterless planographic plate prepared by the following composition and method. The following primer composition was continuously applied to a coil-shaped aluminum plate (manufactured by Sumitomo Metal Co., Ltd.) having a thickness of 0.3 mm and a width of 800 mm, which was degreased by a normal method, and heat-treated at 200 ° C. for 2 minutes to 5 μm. Was applied.

<Solid component: coating concentration 12%> (1) Polyurethane resin (“Samprene” LQ-SZ18; Sanyo Kasei Co., Ltd.) 75 parts by weight (2) Blocked isocyanate (“Takenate” B830; Takeda Yakuhin ( Co., Ltd.) 15 parts by weight (3) Epoxy / urea resin 10 parts by weight <Solvent component> (4) Dimethylformamide Subsequently, a photosensitive layer composition having the following composition is continuously applied onto this, and 120 ° C. After drying for 1 minute, a photosensitive layer of 3 μm was applied.

<Solid component: coating concentration 15%> (1) Obtained by reacting a polyester polyol of adipic acid with hexane-1,6-diol and 2,2-dimethylpropane-1,3-diol and isophorone diisocyanate Polyurethane 57 parts by weight (2) Addition reaction product of 1 mol of metaxylenediamine and 4 mols of glycidyl methacrylate 24 parts by weight (3) 8 parts by weight of polypropylene glycol diacrylate (4) 10 parts by weight of photosensitizer (5) Victoria Poor Blue BOH Naphthalene Sulfonate 0.5 part by weight (6) Maleic acid 0.5 part by weight <Solvent component> (7) Propylene glycol monomethyl ether Subsequently, a silicone rubber layer having the following composition is continuously formed on this photosensitive layer. Coating, heat cure at 115 ° C for 2 minutes, 2μ
m silicone rubber layer was applied.

<Solid component: 8%> (1) 90 parts by weight of polydimethylsiloxane having hydroxyl groups at both ends (degree of polymerization: 700) (2) tris (methylethylketoxime) vinylsilane 9.8 parts by weight (3) dibutyltin dilaurate 2 parts by weight <Solvent component> (4) "Isopar" E (manufactured by Esso Kagaku Co., Ltd.) The waterless planographic plate prepared under the above conditions was attached to a sheet-fed offset printing machine (SPRINT425 Komori Corporation). Coated paper (OK coat manufactured by Oji Paper Co., Ltd.) at a printing speed of 6000 parts / hour using Ink 1 in Example 1 and Ink 6 in Comparative Example 1.
A printing durability test was carried out by printing on.

Further, the waterless planographic plate prepared under the above conditions was set in a Hamada Star offset printing machine, and the ink 3 in Example 3 and the ink 8 in Comparative Example 3 were used at a printing speed of 6000 copies / hour. An amount of 55 kg of high-quality paper was printed, and the ink film was cured using an ultraviolet irradiation device (FWO type manufactured by Toshiba Corp., 2.8 KW) attached after the printing machine, and a printing durability test was performed.

Further, the waterless planographic plate prepared under the above conditions was set in a Hamada Star offset printing machine, and the ink 4 in Example 4 and the ink 9 in Comparative Example 4 were used, and continuous printing was carried out at a printing speed of 6000 parts / hour. Printed on 55 kg high-quality paper, electron beam irradiation device (Iwasaki Electric Co., Ltd., CB1)
75) was used to cure the ink film and a printing durability test was conducted.

Further, the waterless planographic plate prepared under the above conditions was attached to a commercial off-wheel printer (LITHOPIA Mitsubishi Heavy Industries, Ltd.), and ink 2 and ink 5 in Examples 2 and 5, comparative example 2 and Printing was performed on the coated paper (OK coat manufactured by Oji Paper Co., Ltd.) at a speed of 700 rotations / minute using the ink 7 and the ink 10 in No. 5, and a printing durability test was performed.

The evaluation results are shown in Table 1. It can be seen from Table 1 that the printing durability of the waterless planographic printing plate can be improved by using the ink containing the poorly water-soluble compound of the present invention and the hydrotrope agent.

[0106]

[Table 1]

[0107]

The present invention is constructed as described above, and by using the ink of the present invention, it is possible to efficiently plasticize the non-image area of the waterless planographic printing plate and improve the printing durability.

Claims (6)

[Claims] 1. An ink composition for a waterless lithographic plate, comprising at least one poorly water-soluble compound and at least one hydrotrope agent. 2. A waterless lithographic ink composition according to claim 1, which contains 0.01 to 30% by weight in total of a poorly water-soluble compound and a hydrotrope agent. 3. A sheet-fed ink composition for waterless lithographic printing plate containing at least one poorly water-soluble compound and a hydrotrope agent. 4. An off-wheel ink composition for a waterless planographic printing plate containing at least one poorly water-soluble compound and at least one hydrotrope agent. 5. A UV-curable ink composition for waterless lithographic plate, comprising at least one poorly water-soluble compound and at least one hydrotrope agent. 6. An electron beam curable ink composition for a waterless lithographic plate, comprising at least one poorly water-soluble compound and at least one hydrotrope agent.