JPH1071776A - Direct photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten the removability of a hydrophilic layer by abrasion, sensitivity and image reproducibility and favor the inking properties of a printing area by a method wherein the heat conduction of a base material constituting a substrate is set to be below the specified value in a direct photosensitive planographic printing plate. SOLUTION: On a substrate made of a base material having its degree of heat condition of 0.2W/mK or lower, a photosensitive layer con containing light absorber, which absorbs light having at least the wavelength of 600-1,200nm, and a hydrophilic layer are laminated in the order named in order to form a direct photosensitive planographic printing plate. In order to enhance the heat insulating effect by keeping the degree of heat conduction lower, the base material preferably contains gas such as the air or the like so as to realize the low density of 2.0g/cm<3> , as the concrete example of the base material, woodfree paper, resin treated paper, synthetic paper or the like is exampled. Further, a composite substrate is preferably produced by providing an inking layer, which has proper cushioning properties, high adhesion with an ink roller and ink transferability enhancing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct photosensitive lithographic printing plate capable of directly forming a lithographic printing plate by using a semiconductor laser or a light source capable of high-density light exposure according to the semiconductor laser from digital image data. More specifically,
The present invention relates to a direct photosensitive planographic printing plate having at least a photosensitive layer and a hydrophilic layer on a substrate in this order.

[0002]

2. Description of the Related Art In recent years, with the progress of digital image processing technology using a near-infrared semiconductor laser and a computer, a photosensitive lithographic plate has been directly used from digital image data formed on a computer without using a silver halide film for a printing plate. The printing plate is subjected to scanning exposure with a near-infrared semiconductor laser to insolubilize the exposed portion, and then an image is formed by an aqueous solution development process (wet development process) to make a plate, or the exposed portion is deteriorated, sublimated, melted and removed. Laser direct plate making technology, in which an image is formed by performing a dry development process to make a plate, has attracted attention.

[0003] Various attempts have been made for direct photosensitive lithographic printing plates used in the digital printing system. For example, (a) a photosensitive layer and a hydrophilic layer are coated on a support in this order. Those in which the hydrophilic layer is simultaneously melted and removed by volatilization or combustion in response to heat generated by ablation of the exposed portion of the photosensitive layer (Japanese Patent Application Laid-Open Nos. 7-314934 and 55-105560).
(B) A transfer sheet having a photosensitive layer coated on a transparent support is overlaid on a printing plate substrate subjected to a hydrophilization treatment so that the photosensitive layer and the hydrophilized surface are in contact with each other. Laser exposure from the body side and transfer to the substrate surface by ablation of the exposed portion of the photosensitive layer (Japanese Patent Application Laid-Open No. 50-102402). (C) Hydrophobization of the hydrophilic photosensitive layer by laser irradiation Thing (Japanese Unexamined Patent Publication No. 7-185
0) etc. are known. Among these methods, the method (a) is considered to be more preferable because the image forming process is the simplest and the one excellent in normal image quality is easily obtained.

However, in a laser-direct photosensitive lithographic printing plate utilizing the ablation method (a), it has conventionally been difficult to achieve both the strength and the removability of the hydrophilic layer. That is, if the strength of the hydrophilic layer is increased for the purpose of ensuring printing durability, the removability is reduced, and accordingly, the sensitivity, image reproducibility, and ink receptivity of the image portion tend to be reduced. Was.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the sensitivity and image reproducibility of a hydrophilic layer by enhancing the removability of a hydrophilic layer by ablation, and to achieve a direct photosensitivity excellent in ink coverage of an image area. The plan is to provide a lithographic printing plate. Another object of the present invention is to provide a direct print excellent in printing durability such as printing durability and sensitivity, image reproducibility and ink receptivity by providing both the strength and the removability of the hydrophilic layer. It is intended to provide a photosensitive lithographic printing plate.

[0006]

The gist of the present invention resides in that a photosensitive layer containing at least a light absorber for absorbing light of 600 to 1200 nm from a substrate and a hydrophilic layer are provided in this order on the substrate. In a direct photosensitive lithographic printing plate, the thermal conductivity of the substrate constituting the substrate is 0.2 W / m.
K or less in direct-sensitive lithographic printing plates.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred substrate used in the present invention has a flexibility that can be set in an ordinary lithographic printing machine,
In addition to the function of a conventional substrate that can withstand the load applied during printing, the heat generated by the energy of light absorbed by the photosensitive layer is prevented from being transmitted to the substrate and diffused, and the ablation of the photosensitive layer and the hydrophilic layer It has the function of enhancing the effect of As described in detail below, the substrate used in the present invention can be used as a base material (hereinafter simply referred to as a base material) itself which is a central element of the structure of the substrate, but for the purpose of adding various functions. And a substrate (hereinafter, referred to as a composite substrate) comprising the base material and an ink-adhesive layer provided on the photosensitive layer side surface (hereinafter, simply referred to as the front surface) and / or a reinforcing layer provided on the back surface. Used.

For the purpose of exhibiting the function of enhancing the effect of the ablation, it is preferable that the base material has a lower thermal conductivity because it has better heat insulating properties, that is, prevents the diffusion of heat. As the substrate used in the present invention, 300K (27
° C) is usually 0.2 W / mK or less.
Those having 15 W / mK or less are preferred.

In order to suppress the thermal conductivity and increase the heat insulating effect, a material containing a gas such as air in the material of the base material, that is, a material having a low density is preferably used. In order to enhance the heat insulating effect, the density of the substrate is 2.0 g / cm ³
Or less, more preferably 1.5 g / cm ³ or less. Specific examples of the base material include papers such as high-quality paper, resin-treated paper, coated paper, synthetic paper made from polypropylene and the like; wood board; foamed polyethylene terephthalate sheet, foamed polypropylene sheet, foamed polyethylene sheet, foamed polystyrene sheet. Foamed plastic sheet such as, but from the viewpoint of dimensional stability of the substrate, chemical resistance to solvents and the like contained in the ink, coated paper,
Art paper, photographic paper base paper, resin-treated paper, synthetic paper, expanded polyethylene terephthalate sheet, expanded polypropylene sheet, expanded polyethylene sheet are preferred.

The thickness of the substrate is 10 μm to 3 mm, preferably 20 μm to 1 mm, more preferably 50 μm to 50 mm.
0 μm. The surface of the base material used in the present invention has an appropriate cushioning property to enhance the ink adhesion of the image portion of the photosensitive lithographic printing plate, has a high adhesion to the ink roller, and has a high ink transfer property. The composite substrate can be manufactured by providing an ink-filling layer that has the effect of increasing the

Specific examples of the ink inking layer include a polyethylene terephthalate sheet, a foamed polyethylene terephthalate sheet, a polypropylene sheet, a foamed polypropylene sheet, a polyethylene sheet, a foamed polyethylene sheet, and the like. It can be used by bonding to the material surface. Among these, a foamed polyethylene terephthalate sheet, a foamed polypropylene sheet and a foamed polyethylene sheet having a density of 1.5 g / cm ³ or less are preferred for the purpose of enhancing the heat insulating effect as well as the ink inking property. In addition, the durability of the printing plate is also improved by providing the ink deposition layer.

The thickness of the ink depositable layer is 10 μm to 1 m.
m, preferably 20 μm to 100 μm, more preferably 20 μm to 75 μm. Further, a reinforcing layer is provided on the back surface of the base material used in the present invention for the purpose of enhancing the durability of the printing plate, and a composite substrate can be manufactured. Examples of the reinforcing sheet used for providing the reinforcing layer include: a sheet used for the base material; a sheet used for the ink deposition layer; a metal plate such as an aluminum plate, a copper plate, and an iron plate; an aluminum foil And the like can be appropriately selected from metal foils and the like. Among these, a polyethylene terephthalate sheet, a foamed polyethylene terephthalate sheet, and an aluminum plate are preferred.

The thickness of the reinforcing layer is 10 μm to 3 mm, preferably 20 μm to 1 mm, more preferably 50 μm to 5 mm.
00 μm. Further, in the present invention, it is also possible to produce a composite substrate in which an ink deposition layer is provided on the surface of the substrate and a reinforcing layer is provided on the back surface. As described above, these base material, ink inking layer, and reinforcing layer respectively have a heat insulating effect,
Since the main purpose is ink deposition and durability, in order to improve the performance as a photosensitive printing plate, it is preferable to make use of the respective features and to appropriately form a multilayer so as to compensate for the mutual shortage. For this reason, the same type of material may be bonded to a base material of a certain material as an ink-filling layer and / or a reinforcing layer.
In order to satisfy each of the durability, a material of a grade suitable for the purpose may be appropriately selected. In the case of a composite substrate, it is of course important that the thermal conductivity of the entire composite substrate is low, but it is essential that the substrate itself be heat-insulating in order to at least secure a heat-insulating region. Therefore, it is preferable that the ink deposition layer provided on the surface is also heat-insulating.

Specific examples of a preferred composite substrate used in the present invention include, for example, an art paper, a high-quality paper, a resin-processed paper, a synthetic paper or a coated paper having a thickness of 50 μm to 500 μm. And a laminated polyethylene terephthalate sheet, expanded polyethylene terephthalate sheet, polypropylene sheet, expanded polypropylene sheet, polyethylene sheet, or expanded polyethylene sheet.
Further, on the back surface of the composite substrate, a reinforcing layer of the same type as the ink
A three-layer structure obtained by laminating a 00 μm aluminum plate can be used.

When laminating an ink-insulating sheet or a reinforcing sheet on the heat-insulating substrate, one or both of the two sheet surfaces to be laminated may be laminated, for example, as described in JP-A-2-25087. After applying an adhesive such as urethane resin to a thickness of 0.1 to 10 μm,
0 to 150 ° C, 0.1 to 50 kg / cm ² , 0.1 to 5
Lamination is performed under the condition of 0 m / s, and an ink-insulating layer or a reinforcing layer is formed on the heat-insulating substrate.

As described in detail above, in the present invention, the substrate means a layer that should be the main heat-insulating function in the substrate structure depending on its physical property value and layer thickness. The relationship between the layer configuration and the substrate can be modified to a degree that can be conceived by those skilled in the art. For example, the heat insulating function is almost equally borne between the base material and the ink depositing layer, or the base material itself is compounded to express the heat insulating function specified in the present invention in an integrated manner. It may be possible to intervene layers.

The photosensitive layer used in the present invention comprises 6
At the same time, the light having a wavelength of 00 to 1200 nm is efficiently absorbed and converted into heat to cause ablation of the photosensitive layer to remove the photosensitive layer, and at the same time, to induce ablation of the hydrophilic layer in response to the heat generated thereby, to melt, volatilize or Burn,
And / or a light absorbing agent having a function of removing the photosensitive layer by pressure during ablation.

The light absorbing agent can be used without any particular limitation as long as it has a function of absorbing light of 600 to 1200 nm and converting light energy to heat energy. And inorganic pigments, organic pigments, metals and the like. More specifically,
For example, carbon black (MA, a product of Mitsubishi Chemical Corporation)
-7, MA-100, MA-220, # 5, # 10, color black FW2, FW2, a product of Degussa
Graphite; metals such as titanium and chromium; metal oxides such as titanium oxide (manufactured by Mitsubishi Materials Corporation, titanium black 13M, etc.), tin oxide, zinc oxide, vanadium oxide, and tungsten oxide; titanium car Metal carbides such as bites; metal borides; JP-A-4-3222
Organic pigments such as black and green, such as inorganic black pigments, azo black pigments, lionol green 2YS, and green pigments 7 described in JP-A-19 are used. In addition, "special functional dyes" (edited by Ikemori and Sumiya, published by CMC Co., Ltd. in 1986), "chemicals of functional dyes" (edited by Higaki, 1
981 (published by CMC Co., Ltd.), "Dye Handbook" (edited by Okawa, Hirashima, Matsuoka, Kitao, published by Kodansha),
A catalog issued by Japan Photographic Dye Laboratories, Inc. in 1995, and Exciton Inc. And dyes having absorption in the near-infrared region described in Laser Dye Catalog published in 1989. 600 like this
Some of the dyes having absorption in the wavelength region of 〜1200 nm are exemplified in Table 1 below.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

[0026]

[Table 8]

[0027]

[Table 9]

[0028]

Table 10 S-34 polymethine dye; IR-820B (manufactured by Nippon Kayaku Co., Ltd.) S-35 nigrosine dye; Color Index Solvent Black 5 S-36 nigrosine dye; Color Index Solvent Black 7 S-37 nigrosine dye; Color Index Acid Black 2 S-38 carbon black; MA-100 (manufactured by Mitsubishi Chemical Corporation) S-39 titanium monoxide; titanium black 13M (manufactured by Mitsubishi Materials Corporation) S-40 titanium monoxide; titanium black 13B (manufactured by Mitsubishi Materials Corporation)

[0029]

[Table 11]

[0030]

[Table 12]

These light absorbers can be used alone or as a mixture of two or more, dissolved or dispersed in a photosensitive layer coating solution, and used. When blending the light absorber,
The compounding ratio in the photosensitive layer is 5 to 10% of the total solid content of the photosensitive layer.
0% by weight, preferably 10 to 98% by weight, more preferably 20 to 95% by weight. If the blending ratio of the light absorber is extremely low, the light cannot be sufficiently absorbed, and the ablation effect tends to decrease. In this case, the thickness of the photosensitive layer is 0.05
To 100 μm, preferably 0.1 to 30 μm, more preferably 0.3 to 10 μm. Alternatively, a photosensitive layer composed of a light absorbing agent can be provided directly on the substrate by vapor deposition or sputtering of the light absorbing agent. In this case, the film thickness is 0.01 to 0.5 μm, preferably 0.1 to 0.5 μm.
02 to 0.4 μm.

In the photosensitive layer used in the present invention, in addition to the above-mentioned light absorbing agent, the purpose is to enhance the coating properties, compatibility with the light absorbing agent, the film strength in the photosensitive layer, and the effect of ablation. Thus, an organic polymer substance can be added. Examples of the organic polymer include unsaturated acids such as (meth) acrylic acid and itaconic acid, and alkyl (meth) acrylate,
Copolymers with phenyl (meth) acrylate, benzyl (meth) acrylate, styrene, α-methylstyrene and the like;
Polymers of alkyl methacrylate or alkyl acrylate represented by polymethyl methacrylate; copolymers of alkyl (meth) acrylate with acrylonitrile, vinyl chloride, vinylidene chloride, styrene, etc .; copolymers of acrylonitrile with vinyl chloride or vinylidene chloride Modified cellulose having a carboxyl group in the side chain; polyethylene oxide; polyvinylpyrrolidone; phenol, o-,
Novolak resin obtained by condensation reaction of m-, p-cresol and / or xylesol with aldehyde, acetone, etc .; polyether of epichlorohydrin with bisphenol A; soluble nylon; polyvinylidene chloride; chlorinated polyolefin; Copolymer of vinyl and vinyl acetate; vinyl acetate polymer; copolymer of acrylonitrile and styrene; copolymer of acrylonitrile with butadiene and styrene; polyvinyl alkyl ether; polyvinyl alkyl ketone; polystyrene;
Polyethylene terephthalate isophthalate; acetylcellulose; acetylpropoxycellulose; acetylbutoxycellulose; celluloid; polyvinyl butyral and the like are used. The compounding ratio of the organic polymer substance in the photosensitive layer is from 0 to 95% by weight of the total solid content of the photosensitive layer,
It is preferably 2-90% by weight, more preferably 5-80% by weight.
% By weight.

In the above-mentioned photosensitive layer, various additives having a hydrophobic group, for example, p-octylphenol / formalin novolak resin, for the purpose of enhancing the inking property of the printing ink,
p-butylphenol / formalin novolak resin, p
-T-butylphenol-benzaldehyde resin, modified novolak resin such as rosin-modified novolak resin,
Further, o-naphthoquinonediazidosulfonic acid esters of these modified novolak resins, fluorine-based surfactants are added, and nitro compounds such as self-oxidizing nitrocellulose, carbonate compounds, sodium nitrate, etc. And nitrates such as ammonium nitrate, peroxides such as benzoyl peroxide and perbenzoate, or azo compounds such as effervescent azodicarbonamide and azobisisobutyronitrile; N, N'-dinitropentamethylenetetramine and the like. Nitroso compounds, p-toluenesulfonylhydrazine, sulfonylhydrazide compounds such as p, p'-oxybis (benzenesulfohydrazine) and the like are used in an amount of 1 to 70% by weight, preferably 5 to 60% by weight based on the total solid content of the photosensitive layer. More preferably, 10
６０60% by weight can be used.

In the present invention, among the compounds that enhance the ablation effect, nitrocellulose and carbonate compounds described below are preferably used. The nitrocellulose used in the present invention is provided on the photosensitive layer by decomposing by the heat generated by the absorption of the near-infrared laser light by the near-infrared absorber and efficiently generating a low-molecular gas. It has a function of accelerating the removal of the laser exposed portion of the silicone rubber layer.

The nitrocellulose is obtained by subjecting natural cellulose purified by a conventional method to nitric acid esterification with a mixed acid,
It is obtained by introducing a part or all of a nitro group into three hydroxyl groups present in a glucopyranose ring which is a constitutional unit of cellulose. The nitrification degree of the nitrocellulose used in the present invention is 2 to 13, preferably 10 to 12.5, and more preferably 11 to 1.
2.5. Here, the degree of nitrification indicates the weight% of nitrogen atoms in nitrocellulose. If the degree of nitrification is extremely high,
Although the effect of accelerating ablation is enhanced, the stability at room temperature tends to decrease, and the nitrocellulose becomes explosive, which poses a danger in handling the nitrocellulose when producing a printing plate. If the nitrification degree is extremely low, the effect of accelerating ablation cannot be sufficiently obtained.

The nitrocellulose has a degree of polymerization of 20.
２００200, preferably 25-150. If the degree of polymerization is extremely high, the removal of the silicone rubber layer will be incomplete, and the ink adhesion of the laser-exposed portion (image portion) tends to be poor. If the degree of polymerization is extremely low, the coating properties of the photosensitive layer become poor and the silicone rubber layer tends to peel off. The compounding ratio of the nitrocellulose in the photosensitive layer is 5 to 80% by weight, preferably 10 to 70% by weight, more preferably 30 to 70% by weight, based on the total solid components of the photosensitive layer.

The carbonate compound used in the present invention is decomposed by the heat generated by the absorption of a near-infrared laser beam by a near-infrared absorbing agent, thereby efficiently generating a low-molecular gas such as carbon dioxide gas. It is considered that the functional layer or the silicone rubber layer has a function of accelerating the removal of the laser-exposed portion, thereby having an effect of remarkably improving the sensitivity. As the carbonate compound, any compound can be used as long as it has at least one atomic group represented by the following formula (I) (hereinafter referred to as a carbonate group) in the molecule.

[0038]

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Typical carbonate compounds used in the present invention include, for example, a dicarbonate (A) and a hydroxyl group or a dicarbonate (A) in the presence of a catalyst such as N, N-dimethylaminopyridine by a known method according to the following formula. Compound (II) obtained by reacting with compound (B) having a carboxyl group is exemplified.

[0040]

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In the carbonate compound (II) used in the present invention, R is, for example, an optionally substituted alkyl group having 1 to 15 carbon atoms, an optionally substituted phenyl group, or an optionally substituted phenyl group. A good naphthyl group, an optionally substituted aromatic heterocyclic group having 2 to 15 carbon atoms, an optionally substituted aralkyl group having 7 to 15 carbon atoms, an optionally substituted acyl having 2 to 15 carbon atoms Group, a (meth) acryloyl group, and the like (each of the above substituents is an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an acyl group having 2 to 15 carbon atoms, 2 to 15 alkoxycarbonyl groups, 2 to 15 carbon acyloxy groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, hydroxyl groups, carboxyl groups, sulfo groups, cyano groups and the like. That).

Of these substituents R, preferably, an optionally substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, an optionally substituted aralkyl group having 7 to 15 carbon atoms, and (meth) acryloyl Groups (each of the aforementioned substituents is an alkyl group having 1 to 10 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a chlorine atom, a bromine atom, and an iodine atom). More preferable examples of R include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an s-butyl group, a t-butyl group,
Pentyl, heptyl, acryloyl, methacryloyl, phenyl, 1-naphthyl, 2-naphthyl, benzyl, 2-hydroxyethyl, 2-methoxyethyl, 2-chloroethyl, 3-acetyloxypropyl Group, 4-acetylphenyl group, 4-ethoxycarbonylphenyl group, 2-furyl group, 2-thienyl group,

[0043]

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And the like. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an s-butyl group, a t-butyl group, a pentyl group, an acryloyl group and a methacryloyl group are more preferred. The number of carbonate groups in the carbonate compound can be arbitrarily selected by selecting the numbers of hydroxyl groups and carboxyl groups in compound (B) used in the above reaction formula.

Among the compounds (B), compounds having a relatively low molecular weight having one to several hydroxyl groups or carboxyl groups include, for example, ethanol, 1-propanol, 2-propanol, 2-methyl-2 Monohydric alcohols such as propanol, 1-butanol and benzyl alcohol; ethylene glycol, propylene glycol, glycerin,

[0046]

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Polyhydric alcohols such as phenol, o-
Monohydric phenols such as cresol, m-cresol, p-cresol, 1-naphthol, 2-naphthol; hydroquinone, pyrogallol,

[0048]

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Polyhydric phenols such as acetic acid, propionic acid, butyric acid, valeric acid, stearic acid, and oleic acid; benzoic acid, naphthalene-1-carboxylic acid, and naphthalene-2-carboxylic acid Monovalent aromatic carboxylic acids such as acids; ethane-1,2-dicarboxylic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid,

[0050]

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And other polyvalent carboxylic acids. By using these compounds having one to several hydroxyl groups or carboxyl groups, a carbonate compound having one to several carbonate groups in the molecule can be obtained.

Among the compounds (B), examples of relatively high molecular weight compounds having many or more hydroxyl groups or carboxyl groups include, for example, hydroxy (α-methyl)
Styrene, hydroxyphenyl (meth) acrylamide, hydroxyphenyl (meth) sulfonamide, hydroxyphenyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth)
(Co) polymers of compounds having a hydroxyl group or carboxyl group such as acrylate, (meth) acrylic acid and itaconic acid, or these compounds, and methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid (Meth) acrylates such as butyl, benzyl (meth) acrylate and phenyl (meth) acrylate, (α-
Copolymers with (methyl) styrene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl acetate and the like. A modified cellulose having a hydroxyl group in a side chain; polyethylene oxide; a novolak resin obtained by a condensation reaction of phenol, o-, m-, p-cresol, and xylesol with aldehydes and ketones; a reaction between epichlorohydrin and bisphenol A Phenoxy resin; soluble nylon and the like. Specific examples of these compounds are shown below.

[0053]

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[0054]

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[0055]

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Of these, acrylate copolymers, novolak resins and phenoxy resins are preferred because of their high ablation effect. By using these compounds having many or more hydroxyl groups or carboxyl groups, a carbonate compound having a large number of carbonate groups in the molecule can be obtained.

In the reaction between the compounds (A) and (B), various carbonate compounds can be appropriately obtained by combining the compounds. In addition, a carbonate compound in which a part or all of a hydroxyl group or a carboxylic acid group is carbonate-esterified can be obtained depending on a quantitative ratio of the compound (A) and the compound (B) in the reaction. Here, the ratio of the carbonate group to the total number of moles of the hydroxyl group, carboxyl group, and carbonate group in the carbonate compound is referred to as esterification rate. Esterification rate is usually 5 to 100
Mol%, preferably 10 to 100 mol%, more preferably 20 to 100 mol%. If the esterification rate is extremely low, the effect of accelerating ablation is reduced. Next, specific examples of the carbonate compound (shown as a combination of the substituent R in the compound (II) and the compound (B)) are shown in Table 2 below, but are not limited thereto.

[0058]

[Table 13]

[0059]

[Table 14]

[0060]

[Table 15]

Specific examples of the carbonate compound different from the structure shown in Table 2 are shown below.

[0062]

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The compounding ratio of the carbonate compound used in the present invention in the photosensitive layer is from 5 to 90% of the total solid content of the photosensitive layer.
%, Preferably 10 to 80%, more preferably 15 to 7%
5%. In the photosensitive layer used in the present invention, a compound capable of decomposing by heat to generate an acid (hereinafter, referred to as an acid generator) is added for the purpose of accelerating the decomposition of the carbonate compound during ablation. be able to.

The thermal acid generator can be appropriately selected from conventionally known photoacid generators, and includes, for example, a photoinitiator for photocationic polymerization, a photoinitiator for photoradical polymerization, and dyes. A known light-generating compound used for a decoloring agent, a photochromic agent, or a microresist, and a mixture thereof. For example, I. Schl
esinger, Photogr. Sci. Eng. ,
18,387 (1974); iodonium salts described in U.S. Pat. No. 4,069,055; V. Crivello etal, Polym
er J. et al. 17, 73 (1985), a sulfonium salt,
J. V. Crivello etal, Macromo
recules, 10 (6), 1307 (1977), onium salts such as the arsonium salts, U.S. Pat.
Organic halogen compounds described in K. 905,815; M
eier et al, J.A. Rad. Curing, 13
(4), 26 (1986); Hayaseetal, J. et al. Polym
er Sci. , 25, 753 (1987).
A photoacid generator having a nitrobenzyl-type protecting group; T
UNOOKA etal, Polymer Prepr
Compounds that generate sulfonic acid upon photolysis, such as iminosulfonates described in ints Japan, 35 (8), and disulfone compounds described in JP-A-61-166544, etc. can be exemplified.

Further, a group that generates an acid by these lights,
Alternatively, a compound having a compound introduced into the main chain or side chain of a polymer, for example, M.P. E. FIG. Woodhouse et
al, J. et al. Am. Chem. Soc. , 104,558
6 (1982); P. Pappas etal,
J. Imaging Sci. , 30 (5), 218
(1986) and the like.

Further, V. N. R. Pilai, Syn
thesis, (1), 1 (1980); Abad
et al, Tetrahedron Lett. ,
(47) 4555 (1971); H. R. Bart
on et al, J.M. Chem. Soc. , (C), 3
29 (1970); U.S. Patent No. 3,779,778;
Compounds that generate an acid by light described in EP 126,712 and the like can also be used. The mixing ratio of these thermal acid generators is 0.5 to 0.5 with respect to the total solid content of the photosensitive layer.
It is 20% by weight, preferably 1 to 10% by weight, and more preferably 2 to 8% by weight.

The hydrophilic layer used in the present invention is in a state where its surface is covered with a thin film of water (wet state) by dampening water supplied at the time of printing. It has a function of preventing lipophilic ink particles from adhering and forming a non-image portion on printed matter. In order to maintain hydrophilicity, the hydrophilic layer contains a hydrophilic binder polymer cured with a crosslinking agent or the like, if necessary, in an amount of 5 to 100% by weight, preferably 20% by weight, based on the total solid content of the hydrophilic layer. ~ 9
The content can be 5% by weight, more preferably 40 to 90% by weight.

The hydrophilic binder polymer is a polymer composed of carbon-carbon bonds, which has, as a side chain, a carboxyl group, an amino group, a phosphoric acid group, a sulfonic acid group, or a salt, a hydroxyl group, an amide group or a polyoxy group. A networked polymer containing at least one and a plurality of hydrophilic functional groups such as ethylene groups, or a heteroatom in which one of carbon atoms and carbon-carbon bonds is composed of at least one or more of oxygen, nitrogen, sulfur, and phosphorus; At least one kind of a hydrophilic functional group such as a carboxyl group, an amino group, a phosphoric acid group, a sulfonic acid group, or a salt, a hydroxyl group, an amide group, or a polyoxyethylene group on a polymer or a side chain thereof connected by atoms and A polymer containing a plurality of poly (meth) acrylates, polyoxyalkylenes, polyurethanes, epoxy Cycloaddition polymerization system, poly (meth) acrylic acid, poly (meth) acrylamide type, polyester type, polyamide type, polyamine type, polyvinyl type, polysaccharide or cellulose derivative-based or the like of the polymer can be exemplified. Among them, any one of a hydroxyl group, a carboxyl group or an alkali metal salt thereof, an amino group or a hydrogen halide salt thereof, a sulfonic acid group or an amine thereof, an alkali metal salt, an alkaline earth metal salt, an amide group or a amide group on a segment side chain. And those having a hydrophilic functional group and a polyoxyethylene group partially overlapped with the main chain segment are preferable because of high hydrophilicity. In addition to these, those having a urethane bond or a urea bond in the main chain or side chain of the hydrophilic binder polymer are more preferable because not only the hydrophilicity but also the printing durability of the non-image area are improved.

The hydrophilic binder polymer used in the present invention may contain various other components described below, if necessary. Specific examples of the hydrophilic binder polymer of the present invention are shown below. (Meth) acrylic acid or its alkali, amine salt, itaconic acid or its alkali, amine salt, 2-hydroxyethyl (meth) acrylate,
(Meth) acrylamide, N-monomethylol (meth)
Acrylamide, N-dimethylol (meth) acrylamide, 3-vinylpropionic acid or its alkali,
Amine salts, vinylsulfonic acid or its alkali,
Amine salt, 2-sulfoethyl (meth) acrylate, polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, allylamine or halogenated thereof Use at least one of hydrophilic monomers having a hydrophilic group such as a hydroxyl group such as a hydrochloride, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, phosphoric acid or a salt thereof, an amide group, an amino group, and an ether group. To synthesize a hydrophilic homo- or copolymer.

The hydrophilic binder polymer having a functional group such as a hydroxyl group, a carboxyl group, an amino group or a salt thereof, or an epoxy group in the hydrophilic polymer utilizes these functional groups to form a vinyl group, an allyl group, a (meth) acrylic group. An ethylene addition polymerizable unsaturated group such as a group or a cinnamoyl group,
An unsaturated group-containing polymer into which a ring-forming group such as a cinnamylidene group, a cyanosinnamylidene group or a p-phenylenediacrylate group is introduced is obtained. If necessary, a monofunctional or polyfunctional monomer copolymerizable with the unsaturated group, a polymerization initiator described below, and other components described below are added, and the mixture is dissolved in an appropriate solvent to adjust a dope. This is coated on a support and subjected to three-dimensional crosslinking after drying or also as drying.

A hydrophilic binder polymer containing an active hydrogen such as a hydroxyl group, an amino group or a carboxyl group is added together with an isocyanate compound or a blocked polyisocyanate compound and other components described below to the above active hydrogen-free solvent to prepare a dope. Then, it is applied to a support and reacted after drying or while also drying to form a three-dimensional crosslink. A monomer having a glycidyl group such as glycidyl (meth) acrylate and a carboxyl group such as (meth) acrylic acid can be used in combination as a copolymer component of the hydrophilic binder polymer. The hydrophilic binder polymer having a glycidyl group is used as a crosslinking agent such as α, ω-alkane or alkenedicarboxylic acid such as 1,2-ethanedicarboxylic acid and adipic acid, 1,2,3-propanetricarboxylic acid, trimellitic acid and the like. Polycarboxylic acid, 1,2-ethanediamine, diethylenediamine, diethylenetriamine,
Polyamine compounds such as α, ω-bis- (3-aminopropyl) -polyethylene glycol ether, oligoalkylenes or polyalkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol and tetraethylene glycol, trimethylolpropane, glycerin, pentaerythritol Sorbitol and the like, and three-dimensional crosslinking can be carried out by utilizing a ring opening reaction with these.

The hydrophilic binder polymer having a carboxyl group or an amino group may be used as a crosslinking agent such as ethylene or propylene glycol diglycidyl ether, polyethylene or polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether,
Three-dimensional crosslinking can be performed by using an epoxy ring-opening reaction using a polyepoxy compound such as 1,6-hexanediol diglycidyl ether or trimethylolpropane triglycidyl ether.

Polysaccharides such as cellulose derivatives, polyvinyl alcohol or partially saponified products thereof, glycidol homo- or copolymers, or hydrophilic binder polymers based on these are used for the above-mentioned functional groups capable of undergoing a cross-linking reaction by utilizing the hydroxyl groups contained therein. Groups can be introduced to provide a three-dimensional crosslinked structure in the manner described above. Polyol containing hydroxyl group or amino group at the polymer terminal such as polyoxyethylene glycol or polyamine and polyisocyanate such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate The hydrophilic polyurethane precursor synthesized from the above can be three-dimensionally crosslinked by the above-mentioned method using a polymer in which an ethylene addition polymerizable unsaturated group or a ring-forming group is introduced.

The synthesized hydrophilic polyurethane precursor is
When it has an isocyanate group terminal, glycerol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N-monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, Compounds having active hydrogen such as (meth) acrylic acid, cinnamic acid, and cinnamic alcohol, or (meth) acrylic acid, glycidyl (meth) acrylate, 2-isocyanatoethyl ( (Meth) acrylate and the like.

After the application of the polybasic acid and the polyol or the polybasic acid and the polyamine, the network structure is formed by heating to form a three-dimensional cross-link, or a water-soluble colloid-forming compound such as casein, glue or gelatin is formed to form a three-dimensional cross-link by heating. May be formed. Furthermore, hydroxyl- and amino-group-containing hydrophilic compounds such as homo- or copolymers synthesized from hydroxyl-containing monomers such as 2-hydroxyethyl (meth) acrylate and vinyl alcohol, and allylamines, polysaccharides such as partially saponified polyvinyl alcohol, and cellulose derivatives, and glycidol homo or copolymers. There is also a method of forming a three-dimensionally cross-linked hydrophilic binder polymer by reacting a hydrophilic polymer with a polybasic acid anhydride having two or more acid anhydride groups in one molecule.

Examples of polybasic acid anhydrides include ethylene glycol bis anhydro trimellitate, glycerol tris anhydro trimellitate, 1,3,3
a, 4,5,9b hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2
-C] furan-1,3-dione, 3,3 ', 4,4'-
Diphenylsulfonetetracaric anhydride, 1,2,2
3,4-butanetetracarboxylic dianhydride can be exemplified.

An active hydrogen-containing compound such as a polyamine or a polyol having an isocyanate group at the end thereof and an active hydrogen-containing compound such as a polyol and other components described below are dissolved or dispersed in a solvent and coated on a support to remove the solvent. Can be cured at a temperature that does not destroy it to form a three-dimensional crosslink. In this case, hydrophilicity may be imparted by introducing a hydrophilic functional group into either or both segments and side chains of the polyurethane or the active hydrogen-containing compound. The segment and the functional group that express hydrophilicity may be appropriately selected from the above description.

Examples of the polyisocyanate compound that can be used include 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, Bicycloheptane triisocyanate can be exemplified.

In handling before and after the coating step, it is sometimes preferable to block (mask) the isocyanate group by a known method in order to prevent the isocyanate group from changing. For example, Keiji Iwata, "Plastic Materials Course Polyurethane Resin", Nikkan Kogyo Shimbun (1974), pp. 51-52, Keiji Iwata, "Polyurethane Resin Handbook", Nikkan Kogyo Shimbun (198)
7), pages 98, 419, 423, 499, etc., sodium acid sulfite, aromatic secondary amine, tertiary alcohol, amide, phenol, lactam, heterocyclic compound, ketoxime and the like can be used. Preferably, the isocyanate regeneration temperature is low and hydrophilic, and examples thereof include sodium acid sulfite.

An addition-polymerizable unsaturated group may be introduced into any of the above-mentioned unblocked or blocked polyisocyanates and used for strengthening crosslinking or reacting with lipophilic components. The degree of the degree of cross-linking, such as the average molecular weight between cross-links, varies depending on the type of segment used, the type and amount of the associative functional group, and the like, but may be determined according to the required printing durability. Normal,
The average molecular weight between crosslinks is set in the range of 500 to 50,000.
If it is shorter than 500, it tends to be brittle, and if it is longer than 50,000, it may be unfavorable because it swells with fountain solution and printing durability is impaired. 80 on balance of printing durability and hydrophilicity
It is practical to use about 0 to 30,000, and more preferably about 1,000 to 10,000.
The hydrophilic binder polymer of the present invention may be used in combination with the following monofunctional monomers and polyfunctional monomers.

More specifically, Shinzo Yamashita and Tosuke Kaneko, “Handbook of Crosslinking Agents” Taiseisha Publishing (1981), Kiyomi Kato, “Ultraviolet Curing System” Published by General Technology Center (198)
9), edited by Kiyomi Kato, "UV / EB Curing Handbook (raw material)", Polymer Publishing Association (1985), supervised by Kiyoshi Akamatsu, "Practical technology of new photosensitive resin", CMC, pp. 102-14.
, (1987), N, N'-methylenebisacrylamide, (meth) acryloylmorpholine, vinylpyridine, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N
-Dimethylaminopropyl (meth) acrylamide,
N, N-dimethylaminoethyl (meth) acrylate,
N, N-diethylaminoethyl (meth) acrylate,
N, N-dimethylaminoneopentyl (meth) acrylate, N-vinyl-2-pyrrolidone, diacetone acrylamide, N-methylol (meth) acrylamide,
P-styrenesulfonic acid and its salts,

Methoxytriethylene glycol (meth)
Acrylate, methoxytetraethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate (PEG has a number average molecular weight of 40
0), methoxypolyethylene glycol (meth) acrylate (number average molecular weight of PEG 1000), butoxyethyl (meth) acrylate, phenoxyethyl (meth)
Acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, nonylphenoxyethyl (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, polyethylene glycol di (meth) acrylate (PEG number average molecular weight 400 ), Polyethylene glycol di (meth) acrylate (PEG
Number average molecular weight 600), polyethylene glycol di (meth) acrylate (PEG number average molecular weight 100
0), polypropylene glycol di (meth) acrylate (PEG number average molecular weight 400),

2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 2,2
-Bis [4- (methacryloxypolyethoxy) phenyl] propane or its acrylate, β- (meth)
Acryloyloxyethyl hydrogendiene phthalate,
β- (meth) acryloyloxyethyl hydrogen succinate, polyethylene or polypropylene glycol mono (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate,

Tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, isobornia (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isodecyl (meth) acrylate , Cyclohexyl (meth) acrylate, tetrafurfuryl (meth) acrylate, benzyl (meth) acrylate, mono (2-acryloyloxyethyl) acid phosphate or its methacrylic body, glycerin mono- or di (meth) acrylate,
Tris (2-acryloxyethyl) isocyanurate or its methacrylic product, N-phenylmaleimide, N-
(Meth) acryloxysuccinimide, N-vinylcarbazole, divinylethyleneurea, divinylpropyleneurea and the like.

The hydrophilic layer used in the present invention has a particle size of 10 to 4 for the purpose of improving the water retention of the dampening solution.
0 nm colloidal silica, colloidal alumina having a particle size of 10 to 100 nm, acetic acid, formic acid, citric acid, tartaric acid, malic acid, carboxylic acid such as itaconic acid or a carboxylate alone or a mixture thereof is used as the whole of the hydrophilic layer. It can be contained at a compounding ratio of 0 to 90% by weight, preferably 0 to 80% by weight based on the solid content.

Further, in the hydrophilic layer, an appropriate surfactant is added for the purpose of improving the coating property on the photosensitive layer.
0.01 to 10 based on the total solid content of the hydrophilic layer coating solution
It can be contained at a blending ratio of% by weight. In the hydrophilic layer used in the present invention, in order to facilitate the removal of the hydrophilic layer during ablation of the photosensitive layer, the photothermal conversion dye or pigment used in the photosensitive layer is added to the total solid content of the hydrophilic layer. 5 to 80% by weight, preferably 10 to 70% by weight,
More preferably, it can be contained at a blending ratio of 20 to 60% by weight.

The hydrophilic layer used in the present invention has a thickness of
It is 0.1 to 100 μm, preferably 0.2 to 50 μm, and more preferably 0.5 to 20 μm. The present invention provides a direct photosensitive printing plate having the above-described photosensitive layer and hydrophilic layer provided on a substrate, a semiconductor laser beam oscillating light of 600 to 1200 nm or a light source equivalent thereto, such as a xenon flash or a light emitting diode. Focus the light density,
5 MW / m ² or more, preferably 10 MW / m ² or more, more preferably 20 MW / m ² or more, especially 100 MW / m ²
Scanning exposure is performed using a beam spot of m ² or more, and an exposed portion is ablated to form an image. The beam diameter is usually 5 to 30 μm. The photosensitive lithographic printing plate of the present invention is used as a printing plate without post-processing after ablation, and removes fine particles of a photosensitive layer or a hydrophilic layer generated by ablation attached to the exposed printing plate. For the purpose, the hydrophilic layer surface may be subjected to a post-treatment for applying a physical stimulus such as a brush, a pad, an ultrasonic wave or a spray while supplying an aqueous solution or an organic solvent as needed.

As another method for removing the fine particles generated by the ablation, a cover sheet having a surface having higher adhesiveness to the fine particles than the hydrophilic layer can be obtained by exposing a hydrophilic layer of a photosensitive printing plate which has been exposed to light. Above, a method of peeling after laminating so that the hydrophilic surface and the adhesive cover sheet surface fit together, and before exposure, the cover sheet is a cover sheet that transmits laser light in the same manner as described above, Examples of the method include peeling after exposure and a method of removing fine particles on the hydrophilic layer. Examples of the cover sheet include a base plate made of polyethylene terephthalate, polypropylene, polycarbonate, paper, and the like, on which an adhesive layer made of silicone rubber, ionomer, vinyl acetate, or the like is provided as necessary.

The present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. Examples 1 to 9 and Comparative Example 1 The following photosensitive layer compositions were applied on the substrates shown in Table 3 below.

[Photosensitive layer composition] Light absorber: Compound shown in Table 3 Compounding amount shown in Table 3 Organic polymer substance: Compound shown in Table 3 Compounding amount shown in Table 3 Addition Agent: Compound shown in Table 3 Compounding amount shown in Table 3 Coating solvent: 500 parts by weight of cyclohexanone 400 parts by weight of N-methylpyrrolidone After coating, dried at 85 ° C. for 3 minutes to obtain a photosensitive film having a dry film thickness of 1.5 μm. Layers were provided. Subsequently, a hydrophilic layer composition having the following composition was applied onto the photosensitive layer.

[Hydrophilic Layer Composition] 100 parts by weight of polyvinyl alcohol (GL-05 manufactured by Nippon Synthetic Chemical Co., Ltd.) 900 parts by weight of water After coating, dried at 100 ° C. for 4 minutes and dried film thickness 1.2 μm
And a photosensitive printing plate was prepared.

The photosensitive printing plate was fixed on a rotating drum having a circumference of 20 cm so that the hydrophilic layer was on the outside, and the drum was rotated. Next, on the rotating printing plate, 830n
m, 30 mW semiconductor laser light (Hitachi Ltd., H
L8325G) was condensed to a beam diameter of 30 μm and subjected to scanning exposure (corresponding to about 133 MW / m ² ). Subsequently, the following items were evaluated. Table 3 shows the results.

[Sensitivity] After the printing plate was scanned and exposed while rotating the rotating drum at various rotation speeds,
Observation was performed with a microscope of 0 magnification, and the sensitivity was evaluated based on the maximum scanning speed (cm / s) at which the hydrophilic layer at the laser-exposed portion was removed. The higher the scanning speed, the higher the sensitivity.

[Ink Ink Adhesion] Five times of coating was performed on a printing plate subjected to laser exposure at the highest exposure speed using a sponge to which a developing ink (Developing Ink PI-2 manufactured by Fuji Photo Film Co., Ltd.) was applied. After the treatment, the ink deposition on the laser-exposed portion of the printing plate was evaluated for ink deposition. A: Ink adheres to 80% or more of the laser-exposed area. B: Ink adheres to 70% or more and less than 80% of the laser-exposed portion. C: Ink adheres to a portion of 40% or more and less than 70% of the laser-exposed portion. D: The ink adhering portion is less than 40% of the laser exposed portion.

[0095]

[Table 16]

[0096]

[Table 17]

In Table 3, the abbreviations in the column of substrate represent the following substrates, respectively. [Substrate] K1 : 35 μm thick, 1.2 density on both sides of art paper (heat insulating base material) having a thickness of 100 μm and a density of 1.1 g / cm ^3.
g / cm ³ composite substrate laminated with foamed polyethylene terephthalate sheet. K2 : 10 μm thick, 1.6 density on both sides of art paper (heat insulating base material) having a thickness of 100 μm and a density of 1.1 g / cm ^3.
g / cm ³ composite substrate laminated with a polyethylene terephthalate sheet.

K3 : thickness 100 μm, density 1.1 g / c
on the surface of the m ³ of art paper (insulation substrate), thickness 25μ
m, a composite substrate laminated with a foamed polypropylene sheet having a density of 0.94 g / cm ³ . K4 : Art paper (heat insulating base material) having a thickness of 100 μm and a density of 1.1 g / cm ³ . K5 : a polyethylene terephthalate sheet having a thickness of 100 μm and a density of 1.6 g / cm ³ .

K6 : thickness 100 μm, density 1.1 g / c
on the surface of the m ³ of art paper (insulation substrate), thickness 30μ
m, a foamed polyethylene terephthalate sheet having a density of 1.2 g / cm ³ was laminated, and a thickness of 35 μm was
A composite substrate on which a polyethylene terephthalate sheet having a density of 1.6 g / cm ³ is laminated. K7 : 35 μm thick and 1.2 density on the surface of art paper (heat insulating base material) having a thickness of 100 μm and a density of 1.1 g / cm ^3.
g / cm ³ of a foamed polyethylene terephthalate sheet, and on the back surface, a thickness of 0.2 mm and a density of 2.7 g
/ Compound substrate laminated with aluminum plate of / cm ³ .

When laminating the plastic sheet described in K1, 2 , 3 , 6, 7 on a heat insulating substrate, a polyol (Takelac A36) is placed on the plastic sheet.
H, 25 parts by weight of Takeda Pharmaceutical Co., Ltd.) and 5 parts by weight of polyisocyanate (Takenate A-7, manufactured by Takeda Pharmaceutical Co., Ltd.). After applying and drying at 80 ° C. for 1 minute, 2 kg / cm ² at 80 ° C. so that the coated surface of the plastic sheet and the front or back surface of the heat insulating substrate overlap.
Lamination was performed at 50 cm / min to form a plastic sheet on the heat insulating substrate.

Note that the material used for each of the above substrates is 300K.
The thermal conductivity at (27 ° C.) is as follows. Art paper: 0.14W / mK (Chemical Handbook Basic Edition II Revised 4)
Edition, page 70, 1993, published by Maruzen) Polyethylene terephthalate: 0.29 W / mK (Plastic Data Handbook, page 67, 1980,
In the Table 3, the abbreviations in the column of the organic polymer substance indicate the following. Y1 : Phenoxy resin (PKH-J, manufactured by Union Carbide Co., Ltd.) In Table 3, the abbreviations in the column of additives represent the following. T1 : Nitrocellulose Nitrification degree 12 (% by weight)
Average degree of polymerization 40 T2 : Carbonate compound

[0102]

Embedded image

In Table 3, abbreviations in the column of light absorber ( S-3)
9 , S-41 ) each represents a compound listed in Table 1. Comparative Example 2 The same evaluation as in Example 1 was carried out except that the laser output was 5 mW and the beam spot diameter was 100 μm (corresponding to about 0.7 MW / m ² ). No change was observed on the sample surface even when the beam irradiation was continued for one minute.

[0104]

According to the present invention, it is possible to provide a direct photosensitive lithographic printing plate having high sensitivity, high image reproducibility and excellent ink depositability in an image area.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03F 7/09 501 G03F 7/09 501

Claims (9)

[Claims] 1. The method according to claim 1, wherein at least 60
In a direct photosensitive lithographic printing plate having, in this order, a photosensitive layer containing a light absorber that absorbs light of 0 to 1200 nm, and a hydrophilic layer, the substrate constituting the substrate has a thermal conductivity of 0.2 W / Direct photosensitive lithographic printing plate having a mK or less. 2. The direct photosensitive lithographic printing plate according to claim 1, wherein the density of the substrate is 2.0 g / cm ³ or less. 3. The direct photosensitive lithographic printing plate according to claim 1, wherein the substrate comprises the substrate and an ink deposition layer provided on the photosensitive layer side of the substrate. Print version. 4. The direct photosensitive lithographic printing plate according to claim 3, wherein the ink deposition layer is a foamed plastic. 5. The direct photosensitive lithographic printing plate according to claim 3, wherein the ink-adhesive layer is made of expanded polyethylene terephthalate, expanded polypropylene, or expanded polyethylene. 6. The ink-inkable layer has a density of 1.5 g /
Direct photosensitive lithographic printing plate according to claim 3 to 5, characterized in that cm ³ or less. 7. The direct photosensitive lithographic printing plate according to claim 1, wherein a reinforcing layer is provided on the back surface of the base material. 8. The direct photosensitive lithographic printing plate according to claim 1, wherein the photosensitive layer contains nitrocellulose having a nitrification degree of 2 to 13 and an average polymerization degree of 20 to 200. Print version. 9. The direct photosensitive lithographic printing plate according to claim 1, wherein the photosensitive layer contains a carbonate compound.