JP2002311573A - Direct patterning original plate of waterless planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a direct patterning original plate of a waterless planographic printing plate excellent in scratch resistance. SOLUTION: The direct patterning original plate has at least a heat sensitive layer and a silicone rubber layer on a substrate and the silicone rubber layer has a silicone resin and contains a high molecular weight polydimethylsiloxane having a weight average molecular weight of >=300,000 and a polydimethylsiloxane having a weight average molecular weight of <=150,000.

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, and more particularly to a direct drawing type waterless planographic printing plate precursor that can be directly made by laser light.

[0002]

2. Description of the Related Art A so-called direct drawing type plate making, in which an offset printing plate is produced directly from an original without using a plate making film, is simple, which does not require skill, rapidity in which a printing plate can be obtained in a short time, Taking advantage of features such as rationality that can be selected from various systems according to quality and cost, the company has begun to enter not only the light printing industry but also the fields of general offset printing and flexographic printing. In particular, a new type of various direct-drawing lithographic printing plates has recently been developed with the rapid progress of output systems such as a prepress system, an image setter, and a laser printer. These direct-drawing lithographic printing plates can be classified according to plate-making methods, such as 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, an ink repellent layer or an ink-coated layer by inkjet. And the like. Above all, the method using laser light is resolution,
It is superior to other methods in terms of plate making speed and there are many types.

[0003] The printing plate using the laser light further includes:
There are two types: a photon mode by photoreaction and a heat mode in which photothermal conversion is performed to cause a thermal reaction. In particular, the heat mode method has the advantage that it can be handled in a bright room, and due to the rapid progress of the semiconductor laser as a light source, it has recently attracted much attention,
It is said that it will become the mainstream in the future.

As a lithographic printing plate in the heat mode, a direct drawing type waterless lithographic plate capable of printing without using a dampening solution,
A lithographic plate with a direct drawing type, which performs printing using dampening water, has been developed. Direct-drawing waterless lithographic printing plates have the advantages of obtaining high-quality prints and rapid start-up of printing, and can be developed using a system called pretreatment with an organic solvent and brush rub development in the presence of water. Has the advantage that no alkali developing waste liquid is generated when processing is carried out.

For example, US Pat. No. 5,378,580, JP-A-6-186750, and JP-A-6-199.
No. 064, JP-A-9-244228 and U.S. Pat. No. 5,570,636 describe a direct drawing type waterless lithographic printing plate precursor using a laser beam as a light source, a plate making method thereof, and the like. Further, JP-A-11-22
1977, JP-A-11-157236, JP-A-11-208135, JP-A-11-3342
No. 37, JP-A-11-348442 and the like have proposed a direct drawing type waterless lithographic printing plate containing a metal chelate compound and an active hydrogen group-containing compound in a heat-sensitive layer. This printing plate had very good performance such as sufficient sensitivity for practical use, excellent image reproducibility, high ink repulsion, and stable developability, but depending on how the printing plate was handled,
The problem of scratch resistance that the silicone rubber layer in the non-image area may be damaged is part of the problem.

On the other hand, with respect to the improvement of the silicone rubber layer of the direct drawing type waterless planographic plate relating to such scratch resistance,
JP-A-9-239943, JP-A-9-25843
No. 4, JP-A-9-274331, JP-A-9-27411
JP-A-39497 and JP-A-10-186636 have been proposed, but none of them has been practically sufficient.

[0007] On the other hand, a proposal for improvement of a silicone rubber layer of a direct drawing type waterless lithographic plate relating to scratch resistance has been made in Japanese Patent Application No. 20-131.
It was made in JP-A-01-6663 and partially solved, but it was still insufficient.

[0008]

SUMMARY OF THE INVENTION The present invention has been intensively studied in view of the drawbacks of the prior art, and as a result, it has excellent image reproducibility as a silicone rubber layer particularly suitable for a direct drawing type waterless planographic printing plate precursor. A technique for obtaining a silicone rubber layer having greatly improved scratch resistance has been found.

[0009]

The direct drawing type waterless planographic printing plate precursor of the present invention mainly has the following features in order to solve the above problems. That is, "a direct drawing type waterless lithographic printing plate precursor having at least a heat-sensitive layer and a silicone rubber layer on a substrate, wherein the silicone rubber layer has a silicone resin and has a weight average molecular weight of 300,000 or more. A direct drawing type waterless lithographic printing plate precursor comprising: a molecular weight polydimethylsiloxane; and a polydimethylsiloxane having a weight average molecular weight of 150,000 or less.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The direct-drawing waterless planographic printing plate precursor of the present invention comprises:
A direct-drawing waterless lithographic printing plate precursor having at least a heat-sensitive layer and a silicone rubber layer on a substrate, wherein the silicone rubber layer has a silicone resin and a high-molecular weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more. It is characterized by comprising siloxane and polydimethylsiloxane having a weight average molecular weight of 150,000 or less. As the silicone rubber layer of the direct drawing type waterless planographic printing plate precursor according to the invention, an addition polymerization type is used.

The components constituting the addition polymerization type silicone rubber layer include silicone resin and a weight average molecular weight of 30.
10,000 or more high molecular weight polydimethylsiloxane gum, vinyl group-containing polydimethylsiloxane having a weight average molecular weight of 150,000 or less, SiH group-containing polydimethylsiloxane as a crosslinking agent, and a curing catalyst as a main component. Contains a reaction inhibitor for control purposes.

The polydimethylsiloxane having a molecular weight of 150,000 or less preferably has a vinyl group at a molecular terminal and / or in a main chain, and has a structure represented by the following general formula (I).

[0014]

Embedded image (Wherein, m represents an integer of 2 or more, and R ¹ and R ^{2 each} have 1 carbon atom.
~ 50 substituted or unsubstituted alkyl groups, having 2 to 2 carbon atoms
50 substituted or unsubstituted alkenyl groups, having 4 to 4 carbon atoms
At least one selected from the group of 50 substituted or unsubstituted aryl groups is shown, and may be the same or different. It is preferable from the viewpoint of the ink repellency of the printing plate that 50% or more, more preferably 80% or more of R ² and R ^{3 in} the formula are methyl groups. The molecular weight of the polydimethylsiloxane is preferably from 10,000 to 150,000 from the viewpoints of handleability and ink repellency of the obtained printing plate.

The weight average molecular weight of the polydimethylsiloxane can be determined by performing a gel permeation chromatography measurement. Gel permeation chromatography is a type of liquid chromatography that performs separation based on the difference in molecular size, and is a technique for measuring the molecular weight distribution and average molecular weight of a polymer substance. When a sample solution is injected into a column packed with a particulate gel having pores as large as the size of a polymer chain taken in a dilute solution, a high molecular weight molecule, that is, a molecular size in the solution, is reduced. Larger ones have less penetration into the pores of the gel surface and move faster through the column than lower molecular weights and elute. Using this phenomenon, a gel permeation chromatogram is measured, and then a predetermined data analysis is performed on this curve to obtain a target molecular weight distribution and an average molecular weight. The gel permeation chromatography was measured, and the weight average molecular weight of polydimethylsiloxane was determined in terms of polystyrene.

A high-molecular-weight polydimethylsiloxane having a weight-average molecular weight of 300,000 or more is also indispensable in order to produce an excellent scratch resistance as a synergistic effect by including it in a silicone rubber layer together with a silicone resin described later.

In the present invention, since an addition-curable (polymerized) silicone rubber composition is used as the silicone rubber layer composition, a high molecular weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more is added as the silicone rubber layer composition. It is preferable to use a curable (polymerized) silicone rubber composition, more preferably a silicone rubber composition having a weight average molecular weight of 150,000 or less and having a vinyl group or SiH group at the molecular terminal and / or main chain. That is, it has a structure represented by the formula (I), similarly to those having a weight average molecular weight of 150,000 or less.

In the formula (I), m represents an integer of 2 or more;
² , R ³ is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, and a substituted or unsubstituted aryl group having 4 to 50 carbon atoms. At least one of them may be the same or different.

The total of 50 of R ² and R ^{3 in} the formula (I)
% Or more, more preferably 80% or more is a methyl group,
It is preferable in terms of ink repellency of the printing plate.

The content of the high molecular weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more is preferably from 10 to 80% by weight, more preferably from 20 to 70% by weight, based on the solid content of the silicone rubber layer. When the amount is 10% by weight or more, the effect of the addition is sufficiently exhibited. On the other hand, when the amount is 80% by weight or less, the curability of the silicone rubber layer is adversely affected, and the ink repellency is adversely affected. Nothing. The weight average molecular weight of the high molecular weight polysiloxane having a weight average molecular weight of 300,000 or more was determined by performing gel permeation chromatography measurement in the same manner as the polysiloxane having a weight average molecular weight of 10,000 to 150,000.

Examples of the compound having a SiH group include polydimethylsiloxane having a SiH group in a molecular chain or at a terminal. For example, the compound represented by the following general formula (II):
The compound represented by (V) can be mentioned.

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image (In the above formulas (II) to (IV), n represents an integer of 1 or more;
m represents an integer of 1 or more. )

[0025]

Embedded image

SiH in a compound having a SiH group
The amount of the group is preferably 2 or more, more preferably 3 or more in one molecule.

The amount of the compound having a SiH group is 0.1 to 30% by weight based on the solid content of the silicone rubber layer.
And more preferably 1 to 15% by weight.

Such a compound having a SiH group has a carbon-to-carbon ratio of SiH group / polydimethylsiloxane in terms of the quantitative ratio to the vinyl group-containing polydimethylsiloxane.
The molar ratio of carbon double bonds is preferably from 1.5 to 40, and more preferably from 3 to 20. When the molar ratio is 1.5 or more, the curing of the silicone rubber layer does not become insufficient. On the contrary, when the molar ratio is 40 or less, the physical properties of the rubber become brittle, which may adversely affect the scratch resistance of the printing plate. Absent. The silicone resin referred to in the present invention is a polyorganosiloxane having a three-dimensional network structure, which is different from the above-mentioned vinyl-containing polydimethylsiloxane, hydroxyl-containing polydimethylsiloxane, and SiH-group-containing polydimethylsiloxane as a crosslinking agent. Something to be done. Examples of the silicone resin include a straight silicone resin whose components are mainly composed of silicone, and a silicone-modified organic resin that is a copolymer of a silicone component and an organic resin. A straight silicone resin is preferred from the viewpoint of ink repellency and the like.

As straight silicone resins, D units (R ₂ SiO _2/2 : R is an organic group such as a methyl group, a phenyl group or a vinyl group) and T units (R
SiO _3/2 : R is a DT resin containing, as a main constituent unit, a DT resin containing a methyl group, a phenyl group, an organic group such as a vinyl group, and an M unit (R ₃ SiO _1/2 : R is a methyl group, a phenyl group, a vinyl group, etc.) An organic group), an MQ resin containing a Q unit (SiO _4/2 ) as a main constituent unit, a polyorganosilsesquioxane composed of only a T unit, and a ladder polymer having a T unit bonded regularly.

The straight silicone resin is roughly classified into a methyl silicone resin having an organic group mainly consisting of a methyl group and a methylphenyl silicone resin having both phenyl groups. Straight silicone resins are preferred.

Further, as the silicone resin preferably used in the present invention, those having a functional group involved in curing of silicone rubber, such as SiH group and vinyl group, are preferable.

In particular, when an addition-curing (polymerization) type silicone rubber composition is used as the silicone rubber layer composition as in the present invention, a silicone resin having a SiH group or a silicone resin having a vinyl group may be used. This is a particularly preferred combination.

The silicone resin can be obtained by hydrolyzing the corresponding chlorosilane and then polymerizing it. For example, a DT type methyl silicone resin is obtained by hydrolyzing dimethyldichlorosilane and methyltrichlorosilane in a solvent such as toluene or xylene, and then polymerizing the same. The obtained silicone resin has several percent of hydroxyl groups, and if necessary,
By further heating, a high molecular weight type silicone resin having no hydroxyl group can be obtained. Silicone resins having functional groups such as SiH groups and vinyl groups
It can be obtained by mixing a required amount of chlorosilane having a functional group such as an H group or a vinyl group in a raw material, or can be obtained by chemical modification of a silicone resin having several percent of hydroxyl groups.

The content of these silicone resins is preferably from 0.01 to 5% by weight, more preferably from 0.1 to 3% by weight, based on the solid content of the silicone rubber layer. When the amount is 0.01% by weight or more, the effect of the addition is sufficiently exhibited. On the other hand, when the amount is 5% by weight or less, the curability of the silicone rubber layer is adversely affected, and the ink repellency is adversely affected. Never give.

The curing catalyst is a group III transition metal compound, preferably a platinum compound. Specifically, platinum alone, platinum chloride, chloroplatinic acid, olefin-coordinated platinum, an alcohol-modified platinum complex, and platinum methyl A vinyl polysiloxane complex can be given as an example. The amount of such a curing catalyst is 0.01 to 20% by weight, preferably 0.1 to 10% by weight as a solid content in the silicone rubber layer. When the amount of the catalyst to be added is 0.01% by weight or more, the curing of the silicone rubber layer becomes sufficient, and there is no problem in the adhesion to the heat-sensitive layer. On the other hand, when the content is 20% by weight or less, the pot life of the silicone rubber layer solution is not adversely affected. In terms of the amount of metal such as platinum in the silicone rubber layer composition, 10 to 10
It is preferably 00 ppm, preferably 100 to 500 ppm.

Examples of the reaction inhibitor include a nitrogen-containing compound, a phosphorus compound, and an unsaturated alcohol, and an acetylene group-containing alcohol is preferably used.
The preferable addition amount of the reaction inhibitor is 0.01 to 10% by weight in the silicone rubber composition, more preferably 1 to 10% by weight.
~ 5% by weight.

In addition to these compositions, hydrolyzable functional group-containing silanes or siloxanes, known silane coupling agents, titanate-based coupling agents, aluminum-based coupling agents, etc. for the purpose of improving adhesiveness are also used. May be contained. As the silane coupling agent, alkoxysilanes, acetoxysilanes, ketoximine silanes and the like are preferable, and those having a vinyl group and ketoximine silanes are particularly preferable.

When ketoximine silanes are used,
It is particularly preferable because it is a nitrogen-containing compound and thus functions as a reaction inhibitor as well as functions as an adhesion-imparting agent.

The addition amount of such a compound is preferably 0.5 to 20% by weight, more preferably 1 to 5% by weight, based on the total composition of the silicone rubber layer.
When the content is more than 0.5% by weight, the effect of exhibiting the adhesiveness is exerted. On the other hand, when the content is 20% by weight or less, sufficient ink resilience can be exhibited.

As a method for obtaining a silicone rubber layer from the above raw materials, a silicone rubber solution is prepared by dissolving a vinyl group- or hydroxyl group-containing polydimethylsiloxane component in a solvent and then adding a crosslinking agent, a reaction inhibitor, a curing catalyst and the like. And then applying and drying it. The silicone resin component may be added to the above solution at any timing, but is preferably added to a solution in which each polydimethylsiloxane component is dissolved, together with a crosslinking agent, a reaction inhibitor, and the like.

As the solvent, it is preferable to use an aliphatic hydrocarbon or aromatic hydrocarbon solvent. In particular,
Aliphatic hydrocarbons include pentane, hexane, heptane, octane and isoparaffins, normal paraffins, and the like, and aromatic hydrocarbons include toluene, xylene, and mixtures obtained by fractionating petroleum. Specific products that are preferably used as petroleum-based solvents include “ISOPER” and “PEGASO”.
L, “EXXOL”, “SOLVESSO”, “IP
Solvent "and the like.

It is preferable that these solvents be dehydrated in advance, and it is also preferable that the solvent has a dehydration step when preparing the silicone rubber solution. Examples of the dehydrating means include bubbling of a dry gas and introduction of a dehydrating agent such as molecular sieve.However, bubbling of a dry gas is preferable because impurities are not easily brought into a solution.Dry nitrogen gas is particularly preferable because of easy handling. Is preferred. The water content of the solution after dehydration can be measured by a Karl Fischer method or the like, but is preferably suppressed to 40 ppm or less, preferably 20 ppm or less. By sufficiently performing dehydration and keeping the water content to 40 ppm or less, problems such as a decrease in the curability of the silicone rubber solution and a poor adhesion to the heat-sensitive layer do not occur. Further, the pot life is not reduced.

The concentration of the silicone rubber solution is preferably from 3 to 40% by weight, more preferably from 5 to 15% by weight, as a solid content, from the viewpoint of coating properties, drying properties and the like. 3% by weight
By doing so, a certain degree of solution viscosity is ensured, coating properties are improved, and drying efficiency is also obtained. Further, by setting the content to 40% by weight or less, the coating property does not deteriorate due to the increase in viscosity.

The silicone rubber solution thus obtained is applied by various coating methods and dried to obtain a silicone rubber layer. The thickness of the silicone rubber layer is preferably 0.5 to 20 g / m ² , more preferably 1 to 4 g / m ² . When the film thickness is 0.5 g / m ² or more, the ink repellency, scratch resistance and printing durability of the printing plate do not decrease, and when the film thickness is 20 g / m ² or less, it is only advantageous from an economic viewpoint. Also, there is no problem that the developability and the ink mileage are deteriorated.

Next, the heat-sensitive layer in the direct drawing type waterless planographic printing plate precursor according to the invention will be described.

The heat-sensitive layer may be of a metal thin film type,
It may be an organic compound layer containing a photothermal conversion substance.

The metals constituting the metal thin film system include titanium, aluminum, nickel, iron, tellurium, tin, antimony, gallium, germanium, magnesium, polonium, selenium, thallium, zinc, bismuth, and oxides and sulfides thereof. Things. It is preferable to lower the melting point by mixing two or more of these metal compounds to form an alloy. The thickness of the metal thin film is 100
It is preferably 0 Å or less, more preferably 400 Å or less.

The photothermal conversion material used in the organic compound layer includes black pigments such as carbon black and titanium black, phthalocyanine and naphthalocyanine pigments, carbon graphite, diamine metal complexes, dithiol metal complexes, and phenol. Thiol-based metal complexes,
Examples include metal oxides such as mercaptophenol-based metal complexes, titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, and tungsten oxide, and hydroxides and sulfates of these metals.

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

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

Particularly preferred dyes are cyanine-based dyes,
Phthalocyanine type, naphthalocyanine type, dithiol metal complex type, piazurenium type, squarylium type, croconium type, azo type disperse dye, bisazo type, bisazostilbene type, naphthoquinone type, anthraquinone type, perylene type, polymethine type, indoaniline metal Complex dyes,
Intermolecular CT system, benzothiopyran-based spiropyran-based,
Nigrosine-based, thioindigo-based, nitroso-based, quinoline-based, and fulgide-based pigments, particularly dyes, may be mentioned. Further, among these dyes, those having a large molar extinction coefficient ε are preferably used. Specifically, ε is 1 × 1
0 ⁴ or more, more preferably 1 × 10 ⁵ or more. When ε is 1 × 10 ⁴ or more, the effect of improving sensitivity is sufficiently 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.

The content of these light-to-heat converting substances is preferably from 0.1 to 40% by weight, more preferably from 0.5 to 25% by weight, based on the total heat-sensitive layer composition. When the content is 0.1% by weight or more, the effect of improving the sensitivity to laser light is sufficiently obtained, and when the content is 40% by weight or less, the printing durability of the printing plate is not easily reduced.

The heat-sensitive layer preferably contains a metal chelate compound. As metal chelate compounds,
Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, G
e, In, Sn, Zr, Hf metal diketenates, metal alkoxides, alkyl metals, metal carboxylates,
Metal oxide chelates, metal complexes, and heterometal chelates can be mentioned. Among these, particularly preferred compounds are aluminum, iron (III), titanium acetylacetonate (pentanedionate), and ethyl acetoacetonate. (Hexanedionate), propylacetoacetonate (heptanedionate), tetramethylheptanedionate, benzoylacetonates and the like. The amount added to the heat-sensitive layer is preferably 3 to 50% by weight of the solid content, more preferably 5 to 3% by weight.
0% by weight is preferred. When the addition amount is 3% by weight or more, the effect, that is, the effect of improving image reproducibility is high,
On the other hand, when the content is 30% by weight or less, the physical properties of the heat-sensitive layer are hardly reduced, and for example, a problem of printing durability is hardly generated as a printing plate.

When a metal chelate compound is used, a phenolic hydroxyl group-containing compound, an alcoholic hydroxyl group-containing compound, an amino group-containing compound, a carboxyl group-containing compound, a diketone group-containing compound, etc. are added from the viewpoint of interaction with the metal chelate compound. Is preferred. The addition amount of these compounds is preferably from 5 to 60% by weight, more preferably from 20 to 50% by weight, based on the total heat-sensitive layer composition. If the content is 5% by weight or more, the effect tends to be large.
If it is less than 10% by weight, the solvent resistance of the printing plate is not easily reduced.

It is preferable that the heat-sensitive layer further contains a binder polymer. In this case, as the binder polymer, from the viewpoint of printing durability of the printing plate, a polymer or copolymer having a glass transition temperature (Tg) of the polymer of 20 ° C. or lower, more preferably a polymer or copolymer having a glass transition temperature of 0 ° C. or lower It is preferable to use As specific examples of the binder polymer, known vinyl polymers,
Examples include unvulcanized rubber, polyoxides (polyethers), polyesters, polyurethanes, polyamides, and the like. The content of these binders is preferably from 5 to 70% by weight, more preferably from 10 to 50% by weight, based on the total heat-sensitive layer composition. When the content is 5% or more, problems tend to occur in printing durability and coating properties of the coating solution, and when the content is 70% by weight or less, there is no adverse effect on image reproducibility.

In addition to the above compounds, nitro group-containing compounds such as nitrocellulose, hydrazine derivatives, azo compounds, azide compounds, carbonate compounds, easily decomposable compounds such as organic peroxides, etc. And
An acid generator, a radical generator and the like may be added.

The thickness of the heat-sensitive layer is 0.1 to 1 in terms of the coating layer.
When it is 0 g / m ^2, it is preferred in terms of printing durability of the printing plate and excellent productivity because the diluting solvent is easily evaporated, and more preferably 1 to 7 g / m ² .

As the substrate used in the direct drawing type waterless planographic printing plate precursor of the invention, any known metal, film, etc. can be used as long as it is a dimensionally stable plate. As such a dimensionally stable plate-like material, those conventionally used as a substrate of a printing plate are preferably exemplified. As such a substrate, paper, plastic (polyethylene, polypropylene, polystyrene, etc.) may be used as a laminate.
Paper, aluminum (including aluminum alloy), metal plates such as zinc and copper, cellulose acetate, polyethylene terephthalate, polyethylene, polyester, polyamide, polyimide, polystyrene, polypropylene, polycarbonate, polyvinyl Aceta
A plastic film such as metal, a paper or a plastic film on which the above-mentioned metal is laminated or vapor-deposited.

Of these, the aluminum plate is particularly preferable because it is extremely stable in dimension and inexpensive. A polyethylene terephthalate film used as a substrate for light printing is also preferably used.

The obtained direct-drawing type waterless planographic printing plate precursor is as follows:
For the purpose of protecting the ink repellent layer, a protective film may be laminated or a protective layer may be formed. Examples of the protective film include a polyester film, a polypropylene film, and a polyvinylidene chloride film.

A method for producing a direct-drawing waterless planographic printing plate precursor using the above materials will be described.

On the above-mentioned aluminum, aluminum alloy or film substrate, a normal coater such as a reverse roll coater, an air knife coater, a gravure coater, a die coater or a Mayer bar coater, or a rotary coater such as a whey coater is used. Apply layer composition 50
Heat and dry at ２００200 ° C. for tens of seconds to several minutes.

Thereafter, a silicone rubber composition containing a hydrophilic component is applied and treated at a temperature of 50 to 200 ° C. for several minutes to obtain a silicone rubber layer.

The direct drawing type waterless planographic printing plate precursor is exposed imagewise with a laser beam from the protective film after the protective film is peeled off. As the laser light source used in the plate-making exposure process of the present invention, those having an emission wavelength range of 300 nm to 1500 nm are used. Among them, a semiconductor laser or a YAG having an emission wavelength range near the near infrared region is used. Lasers are preferably used. Specifically, 780 nm, 830 nm, 1064 n
Laser light having a wavelength of m and a wavelength around m is preferably used for plate making.

The original plate after laser irradiation is developed by a friction treatment in the presence or absence of water or an organic solvent. The friction treatment is performed by wiping the plate surface with a non-woven fabric, absorbent cotton, cloth, sponge, or the like impregnated with a developer, or by rubbing with a rotary brush while showering tap water or the like after pre-treating the plate surface with the developer. be able to. Examples of the developer used in the case of performing the development treatment include, for example, those obtained by adding a surfactant to water or water, and those obtained by adding a polar solvent such as alcohol, ketone, ester, or carboxylic acid to water, A solvent obtained by adding at least one polar solvent to a solvent composed of at least one kind of aliphatic hydrocarbons and aromatic hydrocarbons, or a polar solvent is used. A known surfactant can be freely added to the above-mentioned developer composition.

[0067]

The present invention will be described in more detail with reference to the following examples.

Example 1 A solution having the following composition was applied on a degreased aluminum plate having a thickness of 0.24 mm.
After drying at 0 ° C. for 80 seconds, a heat-sensitive layer having a dry film thickness of 1.5 g / m ² was provided.

<Thermal Sensitive Layer 1> (A) “YKR-2900” (infrared absorbing dye, manufactured by Yamamoto Kasei Co., Ltd.): 10 parts by weight (B) “Nasem Titanium” (titanium di-n-butoxide bis (2,4-pentane) (Dionate), Nippon Chemical Industry Co., Ltd., metal chelate compound): 22 parts by weight (C) "Sumilite Resin" PR54652 (phenol novolak resin, manufactured by Sumitomo Durez Co., Ltd.): 60 parts by weight (D) "Samprene""T-1331D (polyurethane resin manufactured by Sanyo Chemical Industries, Ltd.): 10 parts by weight (E) m-xylylenediamine / glycidyl methacrylate / 3-glycidoxypropyltrimethoxysilane =
1/3/1 mol ratio addition reactant: 15 parts by weight (F) tetrahydrofuran: 800 parts by weight (G) dimethylformamide: 100 parts by weight On this heat-sensitive layer, the following silicone rubber solution was dried at a dry thickness of 2.0 μm. The coating was performed under the conditions of 125 ° C. for 80 seconds, a silicone rubber layer was provided, and a direct drawing type waterless planographic printing plate precursor was obtained.

<Components of Silicone Rubber Solution 1> (a) α, ω-divinylpolydimethylsiloxane (weight average molecular weight: 99000): 100 parts by weight (b) HQM-105 (manufactured by Gelest Inc., S
iH group-containing silicone resin): 3.3 parts by weight (c) α, ω-divinyl polydimethylsiloxane (weight average molecular weight 500,000): 100 parts by weight (d) vinyl tri (methylethylketoximine) silane: 3 parts by weight ( e) "SRX-212" (Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 5 parts by weight (f) "ISOPAR" E (Esso Chemical Co., Ltd., solvent): 770 parts by weight (g ) Toluene: 260 parts by weight The obtained direct drawing type waterless planographic printing plate precursor was GX-360.
0 (plate making machine, manufactured by Toray Industries, Inc.), and irradiation energy 150 mJ using a semiconductor laser (wavelength: 830 nm).
/ Cm ² .

Subsequently, an automatic developing device TWL manufactured by Toray Industries, Inc.
-860KII (Pretreatment liquid: "NP-1" (Toray Industries, Inc.)
And the developing solution: water), and the exposed plate was developed under the condition of a pre-processing time of 30 seconds to obtain a direct-drawing type waterless planographic printing plate.

The obtained printing plate was used as a sheet-fed offset printing machine “Sprint 25” (manufactured by Komori Corporation).
Lithographic ink "Dryocolor NS"
I ", printed on high-quality paper (62.5 kg / chrysanthemum) using indigo (manufactured by Dainippon Ink and Chemicals, Inc.), and evaluated for image reproducibility as a printed material. Good results were obtained to reproduce

The evaluation of scratch resistance was carried out using a Gakushin type dyed material friction fastness tester manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd. That is, the non-image portion (6 cm × 6 cm) of the obtained direct-drawing type waterless lithographic printing plate was attached to the tester, and a brushed pad having a length of about 5 mm of hair (polyester, about 20 μm in diameter) was used. (Kambo Create Co., Ltd.,
"Caperon" NS5100) (2 cm × 3 cm) was rubbed 150 times with a load of 100 g. Thereafter, the above samples were printed to observe the state of scratches. The evaluation was based on the following criteria. As a result, the scratch resistance was good to the extent that scratches and scratches were slightly observed. 5 points: No scratches or scratches are recognized at all. 4 points: Scratches and scratches are slightly observed. 3 points: Scratches and scratches are observed. 2 points: A substantially circular scratch is observed at the center of the sample. 1 point: Scratches are observed on almost the entire surface.

Example 2 A printing plate precursor was prepared in the same manner as in Example 1 except that the composition of the silicone rubber layer was changed as described below, and the evaluation was performed in the same manner.

<Components of Silicone Rubber Solution 2> (a) α, ω-divinylpolydimethylsiloxane (weight average molecular weight: 99000): 100 parts by weight (b) VQM-105 (manufactured by Gelest Inc., vinyl group-containing silicone) Resin): 3.3 parts by weight (c) α, ω-divinylpolydimethylsiloxane (weight average molecular weight 500,000): 100 parts by weight (d) HMS-151 (manufactured by Gelest Inc., both ends methyl (methyl hydrogen) (Siloxane) (dimethylsiloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent):
7 parts by weight (e) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (f) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 5 parts by weight (g) "ISOPAR""E (manufactured by Esso Chemical Co., Ltd., solvent): 770 parts by weight (h) Toluene: 260 parts by weight

Comparative Example 1 A printing plate precursor was prepared in the same manner as in Example 1, except that the composition of the silicone rubber layer was changed to a composition not containing a silicone resin and not containing a high molecular weight polydimethylsiloxane gum as follows. Was prepared and evaluated in exactly the same manner.

<Components of Silicone Rubber Solution 3> (a) α, ω-divinylpolydimethylsiloxane (weight average molecular weight: 99000): 100 parts by weight (b) HMS-151 (manufactured by Gelest Inc., both terminals methyl ( Methyl hydrogen siloxane) (dimethyl siloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent):
7 parts by weight (c) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (d) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 5 parts by weight (e) "ISOPAR""E (Esso Chemical Co., Ltd., solvent): 1035 parts by weight

Example 3 A printing plate precursor was prepared in the same manner as in Example 1 except that the composition of the silicone rubber layer was changed as follows, and the evaluation was performed in the same manner.

<Components of Silicone Rubber Solution 4> (a) DMS-V52 (manufactured by Gelest Inc.
α, ω-divinylpolydimethylsiloxane, weight average molecular weight 132,000): 100 parts by weight (b) CH ₃ SiO _3/2 unit: 80 mol%, (CH ₃ ) ₂ S
iO _2/2 units: 10 mol%, CH ₃ SiO _2/2 : 10 mol% Silicone resin: 3.3 parts by weight (c) α, ω-divinylpolydimethylsiloxane (weight average molecular weight 400,000): 100 parts by weight (d) HMS-151 (manufactured by Gelest Inc., both ends methyl (methyl hydrogen siloxane) (dimethylsiloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent ):
7 parts by weight (e) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (f) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 7 parts by weight (g) "ISOPAR""E (manufactured by Esso Chemical Co., Ltd., solvent): 770 parts by weight (h) Toluene: 260 parts by weight

Example 4 A printing plate precursor was prepared in the same manner as in Example 1 except that the composition of the silicone rubber layer was changed as described below, and the evaluation was performed in the same manner.

<Components of Silicone Rubber Solution 5> (a) DMS-V52 (manufactured by Gelest Inc.
α, ω-divinylpolydimethylsiloxane, weight average molecular weight 132,000): 100 parts by weight (b) CH ₃ SiO _3/2 unit: 80 mol%, (CH ₃ ) ₂ S
iO _2/2 units: 10 mol%, CH ₃ SiO _2/2 : 10 mol% Silicone resin: 3.3 parts by weight (c) α, ω-divinylpolydimethylsiloxane (weight average molecular weight 500,000): 100 parts by weight (d) HMS-151 (manufactured by Gelest Inc., both ends methyl (methyl hydrogen siloxane) (dimethylsiloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent ):
7 parts by weight (e) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (f) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 7 parts by weight (g) "ISOPAR""E (manufactured by Esso Chemical Co., Ltd., solvent): 770 parts by weight (h) Toluene: 260 parts by weight

Example 5 A printing plate precursor was prepared in the same manner as in Example 1 except that the composition of the silicone rubber layer was changed as follows, and the evaluation was performed in the same manner.

<Components of Silicone Rubber Solution 6> (a) DMS-V52 (manufactured by Gelest Inc.
α, ω-divinylpolydimethylsiloxane, weight average molecular weight 132,000): 100 parts by weight (b) CH ₃ SiO _3/2 unit: 80 mol%, (CH ₃ ) ₂ S
iO _2/2 unit: 10 mol%, CH ₃ SiO _2/2 : 10 mol% Silicone resin: 5 parts by weight (c) α, ω-divinylpolydimethylsiloxane (weight average molecular weight 500,000): 150 parts by weight Part (d) HMS-151 (manufactured by Gelest Inc., both ends methyl (methylhydrogensiloxane) (dimethylsiloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent):
7 parts by weight (e) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (f) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 7 parts by weight (g) "ISOPAR""E (solvent, manufactured by Esso Chemical Co., Ltd.): 960 parts by weight (h) Toluene: 390 parts by weight

Comparative Example 2 A printing plate precursor was prepared in the same manner as in Example 5 except that the composition of the silicone rubber layer was changed to a composition not containing a silicone resin and not containing a high molecular weight polydimethylsiloxane gum as follows. Was prepared and evaluated in exactly the same manner.

<Components of Silicone Rubber Solution 7> (a) DMS-V52 (manufactured by Gelest Inc.)
α, ω-divinylpolydimethylsiloxane, weight average molecular weight 132,000): 100 parts by weight (b) HMS-151 (manufactured by GELEST Inc., both ends methyl (methylhydrogensiloxane) (dimethylsiloxane) copolymer, SiH Group-containing polysiloxane, mol% of MeHSiO: 15-18%, crosslinking agent):
7 parts by weight (c) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (d) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 7 parts by weight (e) "ISOPAR""E (Esso Chemical Co., Ltd., solvent): 1035 parts by weight

Comparative Example 3 A printing plate precursor was prepared in the same manner as in Example 5 except that the composition of the silicone rubber layer was changed to a composition not containing a silicone resin as described below, and the evaluation was performed in the same manner. <Components of Silicone Rubber Solution 8> (a) DMS-V52 (manufactured by Gelest Inc.
α, ω-divinylpolydimethylsiloxane, weight average molecular weight 132,000): 100 parts by weight (b) α, ω-divinylpolydimethylsiloxane (weight average molecular weight 500,000): 100 parts by weight (c) HMS-151 ( GELEST Inc., both ends methyl (methyl hydrogen siloxane) (dimethyl siloxane) copolymer, SiH group-containing polysiloxane, mol% of MeHSiO: 15 to 18%, crosslinking agent):
7 parts by weight (d) Vinyl tri (methylethylketoximine) silane: 3 parts by weight (e) "SRX-212" (manufactured by Toray Dow Corning Silicone Co., Ltd., platinum catalyst, curing catalyst): 7 parts by weight (f) "ISOPAR""E (Esso Chemical Co., Ltd., solvent): 1035 parts by weight

[0087]

[Table 1]

As can be seen from the results shown in Table 1, high-molecular-weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more and polydimethylsiloxane having a weight-average molecular weight of 150,000 or less having the silicone resin of the present invention. In the case of a direct-printing printing plate containing (Examples 1 to 5), good scratch resistance was obtained while maintaining excellent image reproducibility.

On the other hand, no silicone resin
When a high-molecular-weight polydimethylsiloxane having a weight-average molecular weight of 100,000 or more and a silicone rubber layer containing no polydimethylsiloxane having a weight-average molecular weight of 150,000 or less were used, the result that the scratch resistance was poor was obtained. .

[0090]

According to the present invention, a direct drawing type waterless planographic printing plate precursor having excellent image reproducibility and particularly excellent scratch resistance can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H096 AA13 BA01 CA06 EA04 EA23 GA01 GA21 GA27 GA45 2H114 AA05 AA22 AA24 BA01 DA04 DA32 DA38 DA52 DA59 DA60 DA62 DA73 DA78 EA03 EA04 FA16 GA34 GA38

Claims (2)

[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,
The direct-drawing type wherein the silicone rubber layer has a silicone resin, and includes a high-molecular weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more and a polydimethylsiloxane having a weight average molecular weight of 150,000 or less. Lithographic printing plate precursor without water. 2. A direct-drawing type containing a silicone resin and comprising a high molecular weight polydimethylsiloxane having a weight average molecular weight of 300,000 or more and a polydimethylsiloxane having a weight average molecular weight of 150,000 or less. A silicone composition for a waterless planographic printing plate precursor.