JPH11245529A - Direct drawing type waterless lithographic printing plate original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the printing durability, and make a silicone rubber layer hard to damage by a method wherein for a direct drawing type lithographic printing plate original plate having at least a heat-sensitive layer and the silicone rubber layer on a base plate in this order, a corona discharging treatment is applied to the base plate. SOLUTION: This direct drawing type waterless lithographic printing plate original plate by which a printing is possible without using damping water, and especially a direct plate-making is possible by a laser beam, is formed by providing at least a heat-sensitive layer and a silicon rubber layer in this order on a base plate. In this case, by applying a corona discharging treatment on the base plate, the adherence between the base plate and the heat-sensitive layer is increased, and the silicon rubber layer is made hard to damage, and also, the printing durability is improved. Also, when necessary, a heat-insulating layer is provided between the base plate and the heat-sensitive layer, and the corona discharging treatment is applied on the heat- insulating layer. The heat-insulating layer to be used in this case preferably adheres well the base plate and the heat-sensitive layer, is stable with time, and in addition, has a favorable solvent resistance for a solvent of a developing liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterless planographic printing plate precursor which can be printed without using dampening water, and more particularly to a direct drawing type waterless planographic printing plate precursor which can be directly made by laser light. Things. More specifically, a support having good printing durability and a silicone rubber layer that is unlikely to be damaged,
In particular, it relates to a direct drawing type waterless lithographic printing plate precursor using a plastic film.

[0002]

2. Description of the Related Art Direct plate making, in which an offset printing plate is produced directly from an original without using a plate making film, is simple, does not require skill, is quick in obtaining a printing plate in a short time, Utilizing features such as rationality that can be selected according to quality and cost from the system,
In addition to the light printing industry, it has begun to enter the general offset printing and gravure printing fields.

In recent years, new types of various lithographic printing materials have been developed recently due to rapid progress in output systems such as prepress systems, imagesetters, and laser printers.

[0004] These lithographic printing plates can be classified according to plate making methods, including a method of irradiating a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode,
A method of forming an ink repellent layer or an ink deposited layer by ink jetting, and the like can be given.

[0005] Above all, the method using laser light is superior to other methods in resolution and plate making speed.
There are many types.

[0006] Lithographic printing plates using this laser beam are further classified into two types: a photon mode based on photoreaction, and a heat mode in which photothermal conversion is performed to cause a thermal reaction.

The photon mode type includes: (1) a high-sensitivity PS plate using a photopolymer; (2) an electrophotographic lithographic plate using an organic photoconductor or zinc oxide; (3) a silver salt lithographic plate; and (4) a silver salt. Compound type lithography (5) There is a direct drawing master and the like, and as the heat mode type, (6) thermal destruction type lithography and the like can be mentioned.

For the above photon mode type,
The thermal destruction method (6) has an advantage that it can be handled in a bright room, and its usefulness has recently been reviewed due to rapid progress of a semiconductor laser as a light source.

For example, JP-A-6-199064,
US Pat. No. 5,339,737, US Pat. No. 5,353,705, EP 0580393, JP-A-6-5572.
No. 3, EP0573091, USP 5378
580, JP-A-7-164773, JP-A-6-186750, JP-A-7-309001, JP-A-9-146264, JP-A-9-146
JP-A-265-265, JP-A-9-236927, and JP-A-9-244228 describe a direct-drawing waterless planographic printing plate precursor using a laser beam as a light source, a plate making method thereof, and the like.

[0010] The heat-sensitive layer of the printing plate precursor of this thermal destruction system comprises:
Carbon black is mainly used as a laser light absorbing compound, and nitrocellulose is used as a thermal decomposition compound. Then, the carbon black is converted into thermal energy by absorbing the laser light, and the heat destroys the heat-sensitive layer. Finally, by removing this portion by development, the silicone rubber layer on the surface is simultaneously peeled off to form an ink-coated portion.

JP-A-9-146264 discloses a compound that converts laser light into heat, a polymer compound having a film-forming ability, a photopolymerization initiator, and a photopolymerizable ethylenically unsaturated compound in a photothermal conversion layer. A negative-working laser-sensitive dampening solution-free lithographic printing plate precursor has been proposed in which a light-to-heat conversion layer and a silicone rubber layer are reacted by subjecting the entire surface to exposure with energy rays after forming a silicone rubber layer. .

Japanese Patent Application Laid-Open No. 9-239942 proposes a release development type printing plate containing a substance which generates an acid in a laser sensitive layer and a polymer compound which is decomposed by the action of an acid.

In addition to the lithographic printing plate using laser light as described above, a heat-bonding direct-drawing waterless lithographic printing plate can be considered as a particularly direct printing type waterless lithographic printing plate.

In this type of plate material, the silicone rubber layer in the laser beam irradiating portion is selectively left and functions as a non-image portion. The mechanism is that the laser beam irradiation increases the adhesion between the silicone rubber layer and the laser-sensitive layer, or the adhesion between the laser-sensitive layer and the substrate underneath, in some way. The silicone rubber layer, or the silicone rubber layer and the laser-sensitive layer, are selectively removed by a subsequent treatment.

As plate materials of this type, for example, JP-A-9-68794, JP-A-9-80745, JP-A-9-120157 and JP-A-9-19.
No. 7659 has been proposed.

Also, US Pat. No. 4,936,211 and Japanese Patent Application Laid-Open No. 7-110444 disclose that a new plate material is automatically cut into a plate cylinder of a plate printing apparatus or a continuous "cut sheet". An apparatus for feeding in a "web" state is described. From Heidelberg PMT Co., Ltd., "QUICK MASTER DI
46-4 "has been commercialized. It is advantageous to use a plastic film which is easy to process and has high flexibility as a support for a plate material used in such an apparatus.

US Pat. No. 5,379,698, Japanese Unexamined Patent Publication No.
314934, JP-A-9-236927,
JP-A-9-104182 describes a direct-drawing waterless lithographic printing plate using a film of polyester or the like as a substrate.

In this printing plate material, a very thin metal thin film is used as the heat-sensitive layer, and a very sharp image can be obtained, which is advantageous in terms of the resolution of the printing plate. Has a problem in that the heat-sensitive layer in the non-image area is peeled off during printing and ink adheres to the printed matter to cause a defect on printed matter.

As described above, the plastic film does not have sufficient adhesiveness with the coating layer, and the resulting waterless planographic printing plate has a silicone rubber layer which is easily damaged and has a printing durability. Are defective.

[0020]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a direct drawing type waterless lithographic printing plate using a support, especially a plastic film, which has good printing durability and is hardly damaged by a silicone rubber layer. Is to do.

[0021]

To solve the above-mentioned problems, the present invention has the following arrangement.

(1) A direct drawing type waterless planographic printing plate precursor having at least a heat-sensitive layer and a silicone rubber layer in this order on a substrate, wherein the substrate is subjected to a corona discharge treatment. None Lithographic printing plate precursor.

(2) The direct drawing type waterless lithographic printing plate precursor according to claim 1, further comprising a heat insulating layer between the substrate and the heat sensitive layer.

(3) The direct drawing type waterless planographic printing plate precursor according to (2), wherein the heat insulating layer is subjected to a corona discharge treatment.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be specifically described below. The present invention improves the adhesive strength between the substrate and the heat insulating layer or the heat-sensitive layer by performing the corona discharge treatment on the substrate of the direct-drawing waterless planographic printing plate precursor, and as a result, the silicone rubber layer It is characterized by improved scratching and press life.

The support used in the present invention includes those conventionally used as a substrate for a printing plate, and these can be suitably used. Specific examples include plastic films such as cellulose acetate, polyethylene terephthalate, polyethylene naphthalate, polyethylene butyrate, polyethylene, polyamide, polyimide, polystyrene, polypropylene, polycarbonate, and polyvinyl acetal. Further, paper on which the above-mentioned plastic film is laminated, resin-coated paper, and the like can be given. Of these, polyethylene terephthalate and polyethylene naphthalate are preferred.

In the present invention, it is important to subject the surface of the plastic film support to a corona discharge treatment. Atmosphere gases for corona discharge treatment are air, nitrogen gas,
Examples include oxygen gas, argon gas, carbon dioxide gas, and vapors of various organic and inorganic compounds. Of these, air is preferred. The condition of corona discharge treatment is 1W
In the range of ^{/ m 2 / min~200W / m 2} / min,
Preferably ^{5W / m 2 / min~100W / m} 2 / min
Range.

The direct-drawing waterless planographic printing plate used in the present invention may be provided with a heat insulating layer according to the purpose of improving plate inspection and heat insulating effect. The heat insulating layer of the direct drawing type waterless planographic printing plate precursor used in the present invention needs to satisfy the following conditions.
That is, the substrate and the heat-sensitive layer are well adhered and stable over time, and the solvent resistance of the developer is good. Those satisfying such conditions include those containing an epoxy resin as disclosed in JP-B-61-54219, polyurethane resins, phenol resins, acrylic resins, alkyd resins, polyester resins, polyamide resins, melamine resins. , Urea resin, benzoguanamine resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride resin, polyvinyl butyral resin, ethylene-vinyl acetate copolymer, polycarbonate resin, polyacrylonitrile-butadiene copolymer, polyether resin, polyether sulfone Resin, milk casein, gelatin and the like can be used. These resins can be used alone or in combination of two or more. Further, a composition obtained by curing a composition similar to that of the heat-sensitive destruction layer with light or heat may be used.

Among these, it is preferable to use a polyurethane resin, a polyester resin, an acrylic resin, an epoxy resin, a urea resin, or the like alone or as a mixture of two or more.

As the anchoring agent constituting the heat insulating layer, a known adhesive such as a silane coupling agent can be used, and organic titanates are also effective.

In the present invention, as the silane coupling agent contained in the heat insulating layer, a non-basic silane coupling agent is preferably used, and in particular, a vinyl-based, acrylic-based, or epoxy-based silane coupling agent is preferably used.

It is optional to add a surfactant for the purpose of further improving coatability.

In the exposed area of the printing plate, since the heat insulating layer is exposed to form an image area, it is preferable to add an additive such as a dye to the primer layer to improve the plate inspection property.

The composition for forming the above-mentioned heat insulating layer is as follows:
The composition solution is prepared by dissolving in a suitable organic solvent such as DMF, methyl ethyl ketone, methyl isobutyl ketone, dioxane, toluene, xylene, and THF. Such a composition solution is uniformly applied on a substrate and heated at a required temperature for a required time to form a heat insulating layer.

The thickness of the heat insulating layer is 0.5 to 50 as a coating layer.
g / m2 is preferred from the viewpoint of the effect of preventing morphological defects on the substrate surface and blocking the adverse chemical effect and economic efficiency, and more preferably 1 to 10 g / m2.

It is more preferable that the surface of the heat insulating layer is subjected to corona discharge treatment. Atmosphere gases for the corona discharge treatment include air, nitrogen gas, oxygen gas, argon gas, carbon dioxide gas, and vapors of various organic and inorganic compounds.
Of these, air is preferred. Conditions for the corona discharge treatment are 1 W / m ² / min to 200 W / m ² / mi.
n, preferably 5 W / m ² / min to 10
The range is 0 W / m ² / min.

Next, the heat-sensitive layer will be described. In the present invention, a heat-sensitive layer containing a light-to-heat conversion substance and a self-oxidizing substance or a metal chelate compound, or a heat-sensitive layer formed of a metal thin film is preferable.

Hereinafter, the photothermal conversion material will be described.
In the present invention, since a direct-drawing type waterless planographic printing plate precursor is used to form an image by irradiating a laser beam, any photothermal conversion material can be used as long as it absorbs the laser beam. can do. The wavelength of the laser light used at the time of exposure may be any wavelength in the ultraviolet, visible, and infrared regions, but a photothermal conversion material having an absorption range according to the wavelength of the laser light used is used. Must be used. In the present invention, since a laser beam having a wavelength in the infrared region can be preferably used, a compound having an absorption region in the infrared region is preferable as the photothermal conversion material.

For example, black pigments such as carbon black, aniline black and cyanine black, phthalocyanines,
Naphthalocyanine-based green pigment, carbon graphite, iron powder, diamine-based metal complex, dithiol-based metal complex, phenolthiol-based metal complex, mercaptophenol-based metal complex, aryl aluminum metal salts, inorganic water-containing inorganic compound, copper sulfate, sulfurated Chromium, silicate compounds, metal oxides such as titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, tungsten oxide,
It is preferable to add additives such as hydroxides and sulfates of these metals, and metal powders of bismuth, tin, tellurium, iron and aluminum.

Of these, carbon black is particularly preferred from the viewpoints of light-to-heat conversion rate, economy and handling.

Carbon black is classified into furnace black, channel black, thermal black, acetylene black, lamp black, etc. according to the production method. Furnace black is available in various types in terms of particle size and other aspects. It is preferably used because it is commercially inexpensive.

[0042] Carbon black having various particle sizes is commercially available. Among them, the average particle size of the primary particles is preferably from 15 nm to 29 nm, more preferably from 17 nm to 26 nm. .

When the average particle size of the primary particles is smaller than 15 nm, the heat-sensitive layer itself becomes transparent and cannot absorb laser light efficiently. When the average particle size is larger than 29 nm, the particles become high. Without being dispersed in the density, the blackness of the heat-sensitive layer does not increase, and similarly, the laser light cannot be efficiently absorbed. This causes a problem that the sensitivity of the printing plate eventually decreases.

The oil absorption of carbon black also affects the sensitivity of the printing plate and the viscosity of the heat-sensitive layer solution.

The heat-sensitive layer of the present invention has an oil absorption of 50 ml /
It is preferably in the range of 100 g to 100 ml / 100 g, more preferably 60 ml / 100 g to 90 ml / 1.
00 g.

When the oil absorption is less than 50 ml / 100 g, the dispersibility of the carbon black is reduced, and the sensitivity of the printing plate is apt to be lowered. When the oil absorption is more than 100 ml / 100 g, the viscosity of the composition solution becomes high. It becomes thixotropic and becomes difficult to handle.

The use of conductive carbon black is also
It is effective for improving the sensitivity of the plate material.

The electric conductivity at this time is 0.01 Ω− ¹
preferably in the cm- ¹ ~100Ω- ¹ cm- ^1, more preferably in a range 0.1Ω- ¹ cm- ¹ ~10Ω- ¹
cm- ¹ .

In addition to the above substances, dyes that absorb infrared or near-infrared rays are also preferably used as photothermal conversion substances.

As these dyes, 400 nm to 1200
Any dye having a maximum absorption wavelength in the range of nm can be used. Preferred dyes include those for electronics,
Recording dyes cyanine, phthalocyanine, phthalocyanine metal complex, naphthalocyanine, naphthalocyanine metal complex, dithiol metal complex, naphthoquinone, anthraquinone, indophenol, indoaniline, pyrylium, thiopyrylium , Squarylium, croconium, diphenylmethane,
Triphenylmethane, triphenylmethanephthalide, triallylmethane, phenothiazine, phenoxazine, fluoran, thiofluorane, xanthene, indolylphthalide, spiropyran, azaphthalide, chromenopyrazole, Leuco auramine, rhodamine lactam, quinazoline, diazaxanthene, bislactone, fluorenone, monoazo, ketone imine, diazo, methine, oxazine, nigrosine, bisazo, bisazostilbene, bis Azooxadiazole, bisazofluorenone, bisazohydroxyperinone, azochrome complex, trisazotriphenylamine, thioindigo, perylene, nitroso, 1: 2 type metal complex, intermolecular CT System, quinoline Quinophthalone-based, fluid-based acid dyes, basic dyes, pigments, oil-soluble dyes, triphenylmethane-based leuco dyes, cationic dyes, azo-based disperse dyes, benzothiopyran-based spiropyrans, 3,9-dibromoanthanthrone, indanth Ron, phenolphthalein, sulfophthalein, ethyl violet,
Methyl orange, fluorescein, methyl viologen, methylene blue, dimrosbetaine and the like can be mentioned.

Among these, dyes for electronics and recording, having a maximum absorption wavelength of 700 nm to 900 n
m, cyanine-based dye, azurenium-based dye, squarylium-based dye, croconium-based dye, azo-based disperse dye, bisazostilbene-based dye, naphthoquinone-based dye, anthraquinone-based dye, perylene-based dye, phthalocyanine-based dye, na Phthalocyanine metal complex dyes,
Black dyes such as dithiol nickel complex dyes, indoaniline metal complex dyes, intermolecular CT dyes, benzothiopyran spiropyrans, and nigrosine dyes are preferably used.

Further, among these dyes, those having a large molar absorbance coefficient are preferably used. Specifically, ε = 1 × 10 ⁴ or more is preferable, and 1 × 1 is more preferable.
Is 0 ⁵ or more. This is because if ε is smaller than 1 × 10 ⁴ , the effect of improving sensitivity is unlikely to be exhibited. These light-to-heat conversion substances alone have an effect of improving sensitivity, but the sensitivity can be further improved by using two or more kinds in combination. In addition, by using two or more types of light-to-heat conversion materials, it is possible to support various types of laser light sources.

The content of these light-to-heat converting substances is preferably 0.1 to 40% by weight, more preferably 0.5 to 25% by weight, based on the total heat-sensitive layer composition. When the amount is less than 0.1% by weight, the effect of improving the sensitivity to laser light is not seen, and when it is more than 40% by weight, the printing durability of the printing plate tends to decrease.

These heat-sensitive layers preferably have a crosslinked structure in order to increase the solvent resistance to printing ink.

Examples of the polyfunctional crosslinking agent used to introduce a crosslinked structure include a polyfunctional isocyanate compound or a polyfunctional epoxy compound, a urea compound, an amine compound, a hydroxyl group-containing compound, a carboxylic acid compound, and a thiol compound. Combinations with compounds are mentioned.

In these cases, a quaternary ammonium salt, KOH or SnC is used as a catalyst for accelerating the reaction.
It is preferable to use a known catalyst such as l ₄ , Zn (BF ₄ ) ₂ and an imidazole compound.

Among the above crosslinking agents, a combination of a polyfunctional epoxy compound and an amine compound is preferred from the viewpoints of curing speed and handleability.

Further, a polyfunctional crosslinking agent having an organic silyl group or an amino group-containing monomer can be preferably used.

The amount of the polyfunctional crosslinking agent to be used is preferably 1 to 50% by weight, more preferably 3 to 40% by weight, based on the whole heat-sensitive layer composition. If it is less than 1 wt%, the solvent resistance of the printing plate tends to decrease, and
If it is larger than this, the printing plate becomes hard and the printing durability tends to decrease.

In order to improve image reproducibility, nitro compounds such as ammonium nitrate, potassium nitrate, sodium nitrate and nitrocellulose, organic peroxides, azo compounds, diazo compounds and hydrazine derivatives are added to the heat-sensitive layer from the viewpoint of improving image reproducibility. May be. Among them, nitrocellulose is a polymer, so it has appropriate viscosity in a solution state, and has a hydroxyl group in the molecule, so that it is easy to form a crosslinked structure of the thermosensitive layer.

In addition to the above, polyacetylene which is known as a conductive polymer which is a thermally decomposable compound,
Polyaniline and the like are also preferably used.

The amount of the self-oxidizing substance or the thermally decomposable compound to be used is preferably 10% by weight or more based on the total heat-sensitive layer composition in view of excellent printing plate sensitivity, and is 80% by weight or less. This is preferred in terms of storage stability of the printing plate. More preferably, it is 20 to 60% by weight.

From the viewpoint of improving image reproducibility, it is also preferable to add a metal chelate compound.

Focusing on the ink mileage of the printing plate,
It is preferable that the silicone rubber layer and the heat-sensitive layer are not removed by laser beam irradiation and development, but only the silicone rubber layer is removed and the heat-sensitive layer remains. It is more preferable to add a metal chelate compound than to add a decomposable compound.

In the present invention, the metal chelate compound means a complex compound or an organometallic compound, and includes a metal diketenate, a metal alkoxide, an alkyl metal, a metal carboxylate, a metal oxide chelate compound, a metal complex, and a hetero metal chelate compound. No.

The "center metal" includes metals and semiconductor atoms in the second to sixth periods of the periodic table, among which metals and semiconductor atoms in the third to fifth periods are preferable. Al, Si, T of fourth period metal
i, Mn, Fe, Co, Ni, Cu, Zn, Ge, fifth
The periodic metals In and Sn are particularly preferred.

Among these metal chelate compounds, particularly preferred compounds are aluminum, iron (III), titanium acetylacetonate (pentanedionate), ethyl acetoacetonate (hexanedionate), and propyl acetoacetonate. (Heptane dionate), tetramethyl heptandionate, benzoylacetonates and the like.

These metal chelate compounds can be used alone or in combination of two or more.

The amount added to the heat-sensitive layer is preferably 3 to 50% by weight, more preferably 10 to 30% by weight, of the solid content forming the heat-sensitive layer. When the amount is less than 3% by weight, the effect, that is, the effect of improving the image reproducibility is lowered, while when it is more than 30% by weight, the physical properties of the heat-sensitive layer are liable to be reduced. This is because the problem of printability is likely to occur.

The heat-sensitive layer preferably contains a binder polymer for the purpose of improving printing durability and storage stability.
The polymer used in the heat insulation layer, that is, polyurethane resin, phenol resin, acrylic resin, alkyd resin,
Polyester resin, vinyl chloride-vinyl acetate copolymer,
Vinyl chloride resin, polyvinyl butyral resin, ethylene-vinyl acetate copolymer, polycarbonate resin, polyacrylonitrile-butadiene copolymer, polyether resin, polyether sulfone resin, milk casein, gelatin, carboxymethyl cellulose, cellulose acetate, cellulose propyl Acetate, cellulose butyl acetate, cellulose triacetate, hydroxypropyl cellulose ether, cellulose derivatives such as ethyl cellulose ether, polyvinyl acetate,
Polystyrene, polystyrene-acrylonitrile copolymer, polysulfone, polyphenylene oxide, polyethylene oxide, polyvinyl alcohol-acetal copolymer, polyvinyl acetal, polyvinyl alcohol-polyacetal copolymer, polyvinyl alcohol-polybutyral copolymer, polyvinyl benzal, Chlorinated polyolefins such as polyvinyl alcohol, ethylene maleic anhydride copolymer, chlorinated polyethylene and chlorinated polypropylene, and the like; among them, cellulose derivatives such as cellulose acetate; and chlorine-containing such as polyvinyl chloride-vinyl acetate copolymer. Copolymers, ethylene-vinyl acetate copolymers, polyurethane resins and acrylic resins are preferably used.

Further, as an anchoring agent for improving the adhesive strength between the support and the thermosensitive layer, for example, a silane coupling agent or the like may be used.
Known adhesives can be used, and organic titanates and the like are also effective.

In the present invention, as the silane coupling agent contained in the heat-sensitive layer, a non-basic silane coupling agent is preferably used, and in particular, a vinyl, acrylic or epoxy silane coupling agent is preferably used.

Further, the heat-sensitive layer may appropriately contain additives such as a preservative, an antihalation dye, an antifoaming agent, an antistatic agent, a dispersant, an emulsifier, and a surfactant.

In particular, it is preferable to add a fluorinated surfactant to improve coatability. The amount of these additives is usually 10% by weight or less based on the total heat-sensitive layer composition.

When an addition type silicone rubber is used for the silicone rubber layer, a compound having an ethylenically unsaturated bond can be added for the purpose of improving the adhesion between the heat-sensitive layer and the silicone rubber layer. Examples of the compound having an ethylenically unsaturated bond include the following compounds,
Among them, epoxy acrylates are particularly preferred. The amount of the compound having an ethylenically unsaturated bond to be used is preferably 0.5 to 30% by weight based on the total heat-sensitive layer composition.

(1) An esterified product of a polyfunctional hydroxyl group-containing compound and acrylic acid or methacrylic acid.

(2) Epoxy acrylates obtained by reacting an epoxy compound with acrylic acid, methacrylic acid, glycidyl acrylate, or glycidyl methacrylate.

(3) A compound obtained by reacting an amine compound with glycidyl acrylate, glycidyl methacrylate or acrylic acid chloride or methacrylic acid chloride.

(4) A compound obtained by reacting a compound having a carboxyl group with glycidyl acrylate and glycidyl methacrylate.

(5) Urethane acrylates The above compounds having two or more ethylenically unsaturated double bonds in one molecule can be used alone or in combination of two or more.

Further, in some cases, in order to improve the adhesion with the additional silicone rubber layer as the upper layer, hydrophobic silica whose surface is treated with a silane coupling agent containing a (meth) acryloyl group or an allyl group is used. The powder may be added in an amount of 20% by weight or less based on the total heat-sensitive layer composition.

The composition for forming the heat-sensitive layer is as follows:
Dissolved in a suitable organic solvent such as DMF, methyl ethyl ketone, methyl isobutyl ketone, dioxane, toluene, xylene, ethyl acetate, methyl propionate, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, acetone, methyl alcohol, ethyl alcohol Thus, a composition solution is prepared. Such a composition solution is uniformly applied on a substrate and heated at a required temperature for a required time to form a heat-sensitive layer.

The physical properties of the heat-sensitive layer thus obtained are preferably in a specific range from the viewpoint of the printing characteristics of the printing plate obtained. As such physical properties, the tensile properties, among which, the initial elastic modulus at the time of tension can be mentioned as a representative. More specifically, the initial elastic modulus of the heat-sensitive layer in the printing plate at the time of tension is 7 kgf / mm ^{2 to} 7 kgf / mm ^2.
In the range of 8 kgf / mm ² , and further in the range of 10 kgf / mm ²
It is preferably in the range of 65 kgf / mm ² .

By setting the initial elastic modulus of the heat-sensitive layer within the above range, the characteristics as a printing plate, particularly the printing durability, can be improved. Conversely, the initial elastic modulus is 7kg
If it is less than f / mm ² , the heat-sensitive layer forming the image area is likely to be sticky, so that it is easy to generate a hitkey during printing. When the initial elastic modulus is 78 kgf / mm ² or more, destruction is likely to occur at the bonding interface between the heat-sensitive layer and the silicone rubber layer due to the repetitive stress applied at the time of printing, which causes a reduction in printing durability. is there.

The thickness of the heat-sensitive layer is set to be 0.
1 to 10 g / m ² is preferable, and 1 to 7 g is more preferable.
/ M ² . If the thickness is less than 0.1 g / m ² , the printing durability of the printing plate tends to decrease.
If the thickness is greater than / m ² , it takes time to volatilize the diluted solvent, which is disadvantageous in terms of productivity, so the above range is preferable.

When the heat-sensitive layer is a metal thin film,
There is no particular limitation as long as deposition and sputtering can be performed. The thickness of the metal is preferably 1000 Å or less, and if it is in the range of 20 to 200 Å, high sensitivity is obtained, and it is particularly preferable.

Specifically, preferred metals include germanium, titanium, aluminum, bismuth, nickel, chromium, tellurium, tin, tungsten, antimony, gallium, polonium, selenium, magnesium, zinc, iron and the like. Tellurium, tin, antimony, gallium, bismuth, titanium, and zinc are more preferred. The use of alloys of these metals is also effective in lowering the melting point and improving the sensitivity as a printing plate.

Next, the silicone rubber layer will be described.
In the present invention, for the silicone rubber layer, any silicone rubber composition used in a conventional waterless lithographic plate can be used. The crosslinking method may be a condensation type or an addition type.

Such a silicone rubber layer is obtained by sparsely cross-linking a linear organosiloxane (preferably dimethylpolysiloxane). A typical silicone rubber layer is represented by the following formula (I). Having various repeating units.

[0090]

Embedded image (Here, n is an integer of 2 or more. R has 1 to 10 carbon atoms.)
Alkyl, aryl, or cyanoalkyl group. Preferably, 40% or less of the whole R is vinyl, phenyl, vinyl halide, or halogenated phenyl, and 60% or more of R is a methyl group. Further, it has at least one or more hydroxyl group in the molecular chain in the form of a chain terminal or side chain. In the present invention, the silicone rubber layer preferably contains a silane coupling agent.

Specific examples of the silane coupling agent include:
Known materials such as vinyl silane, (meth) acryloyl silane, epoxy silane, amino silane, mercapto silane and chloro silane can all be used, and among them, (meth)
Acryloyl silane, epoxy silane, amino silane,
And mercaptosilane.

These silane coupling agents are preferably used at a ratio of 0.1 to 5% by weight, more preferably 0.1% by weight, based on the solid content of the silicone rubber layer composition.
5 to 3% by weight.

The thickness of the silicone rubber layer is 0.5
To 50 g / m ² , more preferably 0.5 to 50 g / m ^2.
10 g / m ² . When the film thickness is less than 0.5 g / m ² , the ink repellency of the printing plate tends to decrease, and
If it is larger than / m ² , it is disadvantageous from an economic point of view.

For the purpose of, for example, protecting the silicone rubber layer on the surface of the waterless planographic printing plate precursor configured as described above, a thin protective film obtained by treating the surface of the silicone rubber layer with a plain or uneven surface is laminated. It is also possible to form a polymer coating film which can be dissolved in a developing solvent described in JP-A-5-323588.

In particular, when a protective film is laminated, laser exposure is performed from above the protective film, and then the protective film is peeled off to form a pattern on the printing plate. It can also be created. Next, a method for producing a waterless planographic printing plate according to the invention will be described.

On a substrate, a composition solution to constitute a heat insulating layer composition is used, if necessary, using an ordinary coater such as a reverse through coater, an air knife coater, or a Meyer bar coater, or a spin coater such as a whey coater. Coating and drying and crosslinking and curing. Next, a composition solution for forming a heat-sensitive layer is applied and dried. Further, the silicone rubber composition is applied in the same manner, and heat-treated at a temperature of 50 to 150 ° C. for several minutes to cure the rubber to form a silicone rubber layer. Then, if necessary, a protective film is laminated or a protective layer is formed.

The thus obtained direct drawing type waterless planographic printing plate precursor is exposed imagewise with a laser beam after peeling off the protective film or from above the protective film.

A laser beam is usually used for exposure, and the light source at this time has an oscillation wavelength of 300 nm to 1500 nm.
Ar ion laser, Kr ion laser, He-Ne laser, He-Cd laser, ruby laser, glass laser, semiconductor laser, YAG laser, titanium sapphire laser, dye laser, nitrogen laser, metal vapor laser, etc. Various lasers can be used. Among them, a semiconductor laser is preferable because it is downsized due to recent technological advances and is economically more advantageous than other laser light sources.

The direct-drawing type waterless planographic printing plate exposed by the above method is subjected to peeling development or ordinary solvent development if necessary.

The developer used in the present invention may be, for example, water, a solution obtained by adding the following polar solvent to water, or at least one of aliphatic hydrocarbons, aromatic hydrocarbons and halogenated hydrocarbons. A mixture obtained by adding at least one polar solvent such as alcohols, ethers, ketones, esters, and carboxylic acids to a mixed solvent of at least one kind is preferably used.

A known surfactant can be freely added to the developer composition. Further, further alkaline agents such as sodium carbonate, monoethanolamine,
Diethanolamine, diglycolamine, sodium silicate, potassium silicate, potassium hydroxide, sodium borate and the like can also be added.

To these developers, known basic dyes such as crystal violet, victor pure blue, and astrazone red, acid dyes and oil-soluble dyes are added to simultaneously develop and dye the image area. Can be.

In the development, the developer can be developed by impregnating a nonwoven fabric, absorbent cotton, cloth, sponge, or the like with the developer and wiping the plate surface.

For the development, see JP-A-63-163357.
Developing can be suitably performed by rubbing the plate surface with a rotary brush while pre-treating the plate surface with the above-mentioned developing solution and then showering with tap water using an automatic developing machine as described in (1).

Development can also be performed by spraying hot water or steam onto the plate instead of the above-mentioned developer.

Hereinafter, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.

[0107]

EXAMPLES The present invention will be further described below with reference to examples of the present invention, but the present invention is not limited to these examples.

Examples 1 to 4 and Comparative Example 1 KNI Power System Co., Ltd. was used as the support, using an 80 μm polyethylene terephthalate film “Lumirror” (manufactured by Toray Industries, Inc.) as an atmospheric gas as described in Table 1. Corona discharge treatment was performed with a corona surface treatment machine R8-8 to form Supports 1 to 4.

[0109]

[Table 1] As a comparative support, an untreated support was designated as comparative support-1. The heat-sensitive composition 1 having the following composition was applied to the support-1 to support-4 and the comparative support-1 formed as described above, and dried at 130 ° C. for 1 minute to obtain a film having a thickness of 1 g / g.
An m ² heat-sensitive layer was formed.

<Thermosensitive Composition 1> (a) Nitrocellulose Viscosity 1/2 second, nitrogen content 11.0% "Bergerac NC" (manufactured by SNP Japan Ltd.) 24 weight Part (b) 30 parts by weight of carbon black (c) 30 parts by weight of polyurethane "SAMPLEN" LQ-T1331 (manufactured by Sanyo Chemical Industries, Ltd.) (d) Modified epoxy resin "Epokey" 803 (manufactured by Mitsui Toatsu Chemicals, Inc.) 15 parts by weight (e) Epoxy acrylate “Denacol Acrylate” DA-314 (manufactured by Nagase Kasei Kogyo Co., Ltd.) 15 parts by weight (f) Diethylenetriamine 5 parts by weight (g) Methyl isobutyl ketone 600 parts by weight A silicone rubber solution 1 having the following composition is applied on the heat-sensitive layer, dried at 120 ° C. for 2 minutes, and has a thickness of 2 g /
An m ² silicone rubber layer was formed.

<Silicone Rubber Solution 1> (a) 100 parts by weight of polydimethylsiloxane (b) 12 parts by weight of hydrogensiloxane (c) 0.2 parts by weight of platinum catalyst (d) 2 parts by weight of curing retarder (e) isoparaffin -Based hydrocarbon Isopar E (manufactured by Exxon Chemical Co., Ltd.) An 8 μm-thick polyester film “Lumirror” (manufactured by Toray Industries, Inc.) was laminated on the laminate obtained above using a calendar roller. A direct-drawing waterless planographic printing plate precursor was obtained.

Thereafter, the printing plate precursor was mounted on a drum, and a semiconductor laser (output: 1 W, wavelength: 830 nm, TE:
Using K (manufactured by K Corporation), pulse exposure was performed at a laser output of 480 mW, a beam diameter of 20 μm, and an exposure time of 10 μs.

Subsequently, the film was rubbed with a cotton pad impregnated with a developing solution having the following composition, and only the silicone rubber layer at the exposed portion was peeled off and developed.

<Developer> (a) 80 parts by weight of water (b) 20 parts by weight of diethylene glycol mono-2-ethylhexyl ether The evaluation of the printing durability was performed by using a four-color printing machine KOMORI SPR
Attach it to INT 425BP (manufactured by Komori Corporation), print on coated paper using waterless lithographic ink (manufactured by Dryocolor NSI Indigo Dainippon Ink and Chemicals, Inc.), and use silicone in the non-image area. The number of printed sheets until the rubber layer peeled into a pinhole and stains occurred on the paper surface was used as an index of printing durability.

Evaluation of the rubbing resistance was performed by stacking three pieces of Heize gauze cut to 6 × 6 cm, impregnating Isopar E into the Heize gauze, and placing a 5 × 5 × 2.5 cm rectangular solid (iron, about 500 g) on the top. The printing plate was rubbed 3000 times. The plate surface after the test was visually observed, and the case where the plate surface was completely free of scratches was evaluated as ○, the case where the plate surface was scratched as Δ, and the case where the plate surface was peeled as ×.

Example 5 A support 3 was coated with a heat-insulating layer composition having the following composition.
After drying at 0 ° C. for 2 minutes, a heat insulating layer of ² g / m ² was formed.

<Insulation layer composition> (a) 10 parts by weight of 4,4-diphenylmethane diisocyanate (b) 5 parts by weight of glycidyl ether "Epolite" 3002 (manufactured by Kyoeisha Yushi Kagaku Kogyo KK) (c) Hydroxyl group-containing polyurethane resin "SAMPLEN" IB-104 (manufactured by Sanyo Chemical Industries, Ltd.) 10 parts by weight (d) Titanium oxide 10 parts by weight (e) N, N-dimethylformamide 155 parts by weight (f) Tetrahydrofuran 700 parts by weight In the same manner as in Example 1, the heat-sensitive composition 1 and the silicone rubber solution 1 were applied to obtain a direct-drawing waterless planographic printing plate precursor. The obtained original plate was evaluated in the same manner as in Example 1.

Example 6 After forming a heat-insulating layer in the same manner as in Example 5, air was used as the atmospheric gas for the heat-insulating layer, and a corona discharge treatment (100 W / cm 2) was performed using a corona surface treatment machine R8-8 manufactured by KNI Power Systems.
m ² / min). Thereafter, the heat-sensitive composition 1 and the silicone rubber solution 1 were applied in the same manner as in Example 1 to obtain a direct-drawing waterless planographic printing plate precursor. The obtained original plate was prepared in Example 1.
The same evaluation was performed.

Example 7 A support 3 was coated with a thermosensitive layer composition 2 having the following composition.
After drying at 0 ° C. for 2 minutes, a heat-sensitive layer of ² g / m ² was formed.

<Thermosensitive Composition 2> (a) 5 parts by weight of SPRIT NIGROSINE SJ (Dye Specialities, INC.) (B) γ-glycidoxypropyltrimethoxysisilane “TSL” 8340 (manufactured by Toshiba Silicone Co., Ltd.) 5 parts by weight (c) Aluminum monoacetylacetonate bisethylacetoacetate "Aluminum Chelate" D (manufactured by Kawaken Fine Chemicals Co., Ltd.) 30 parts by weight (d) Resole resin "Sumilac" PC-1 (Sumitomo Durres Co., Ltd.) 70 parts by weight (e) Polyurethane resin “SAMPLEN” LQ-909L (manufactured by Sanyo Chemical Industries, Ltd.) 20 parts by weight (f) 875 parts by weight of tetrahydrofuran Subsequently, a silicone rubber having the following composition was formed on the heat-sensitive layer. Solution 2 was applied, dried at 120 ° C. for 1 minute, and had a thickness of 2 g /
An m ² silicone rubber layer was formed.

<Silicone Rubber Solution 2> (a) 100 parts by weight of α, ω-divinyl polydimethylsiloxane (polymerization degree 770) (b) Methyl (methylhydrogensiloxane) (dimethylsiloxane) at both ends Copolymer Number of SiH groups / (Molecular weight = 0.69 mol / g) “HMS-501” (manufactured by Chisso Corporation) 4 parts by weight (c) Olefin coordinated platinum 0.02 parts by weight (d) Reaction inhibitor “BY24-808” (Dow Corning Silicone) 0.3 parts by weight (e) "Isopar" E (manufactured by Esso Chemical Co., Ltd.) 1000 parts by weight A direct drawing type waterless planographic printing plate precursor was obtained in the same manner as in Example 1 below. . The obtained original plate was evaluated in the same manner as in Example 1.

Example 8 After forming a heat insulating layer in the same manner as in Example 5, the heat-sensitive composition 2 and the silicone rubber solution 2 were applied in the same manner as in Example 7, and a direct-drawing waterless planographic printing plate precursor was obtained. Obtained. The obtained original plate was evaluated in the same manner as in Example 1.

Example 9 A metal thin film of germanium (1
00 angstroms). The following is Example 7
The silicone rubber solution 2 was applied in the same manner as described above to obtain a direct-drawing waterless planographic printing plate precursor. The obtained original plate was prepared in Example 1.
The same evaluation was performed. Example 10 A metal thin film of titanium (100 Å) was formed on a support 3 by vapor deposition. Thereafter, the silicone rubber solution 2 was applied in the same manner as in Example 7 to obtain a direct-drawing waterless planographic printing plate precursor. The obtained original plate was evaluated in the same manner as in Example 1.

Comparative Example 2 The same heat-insulating layer composition as in Example 5 was applied on Comparative Support-1 to form a heat-insulating layer. Thereafter, the heat-sensitive composition 1 and the silicone rubber solution 1 were applied in the same manner as in Example 1 to obtain a direct-drawing waterless planographic printing plate precursor. The obtained original plate was evaluated in the same manner as in Example 1.

Comparative Example 3 Direct drawing was performed in exactly the same manner as in Comparative Example 2, except that 5 parts by weight of γ-glycidoxypropyltrimethoxysilane “TSL” 8350 (manufactured by Toshiba Silicone Co., Ltd.) was added to the heat insulating layer. A lithographic printing plate precursor without mold water was obtained. The obtained original plate was evaluated in the same manner as in Example 1.

Comparative Example 4 A direct drawing type water was prepared in exactly the same manner as in Comparative Example 1, except that the heat-sensitive composition 2 was used instead of the heat-sensitive layer composition 1 and the silicone rubber solution 2 was used instead of the silicone rubber solution 1. None A lithographic printing plate precursor was obtained. The obtained original plate was evaluated in the same manner as in Example 1.

Next, the results are shown in Table 2.

[0128]

[Table 2] As is clear from Table 2, Examples 1 to 8 of the present invention were used.
Then, the rub resistance is improved. The printing durability was 32,000 in Comparative Example 3, whereas 400 in the present invention.
The number is from 00 to 50,000.

[0129]

According to the present invention, a printing plate obtained by subjecting the surface of a plastic film support to a corona discharge treatment has good printing durability even when a plastic film is used as a support, and a silicone rubber layer. Water-free lithographic printing plate having an excellent effect of preventing scratches.

Claims (3)

[Claims] 1. A direct drawing type waterless planographic printing plate precursor having at least a heat-sensitive layer and a silicone rubber layer on a substrate in this order, wherein the substrate is subjected to a corona discharge treatment. Lithographic printing plate precursor. 2. The direct drawing type waterless planographic printing plate precursor according to claim 1, further comprising a heat insulating layer between the substrate and the heat sensitive layer. 3. A direct drawing type waterless lithographic printing plate precursor according to claim 2, wherein said heat insulating layer is subjected to a corona discharge treatment.