JP2003063165A - Original plate for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an original plate for heat-sensitive lithographic printing plate which can be fitted directly to a printing machine after infrared scanning exposure based on a digital signal without being treated to be ready for printing, has good on-machine development properties, exhibits high plate wear, and is resistant to fouling in printing due to good ink wiping properties. SOLUTION: The original plate for the lithographic printing plate has a lipophilic imaging layer containing fine hydrophobic polymer particles combined by heat, a photothermal conversion agent, and a compound which is insoluble in water and indicates fluidity at 50 deg.C. Further, the plate has a layer not containing a hydrophilic binder resin on an aluminum substrate which is subjected to surface roughening treatment, and has a hydrophilic film and an overcoat layer containing a water-soluble resin on the imaging layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a development-free lithographic printing plate precursor for a computer to plate (CTP) system. More specifically, it is possible to record an image by infrared scanning exposure based on a digital signal, and the image-recorded product can be directly mounted on a printing machine and printed without undergoing a conventional liquid development process. The present invention relates to a heat-sensitive lithographic printing plate precursor.

[0002]

2. Description of the Related Art Conventionally, a lithographic printing plate has been produced by a system in which a lithographic film as an intermediate material is used to expose a printing plate precursor. However, with the rapid progress of digitization in the printing field in recent years, the production process of this printing plate is changing to a CTP system in which digital data input to a computer and edited is directly output to a printing plate original plate. Among them, with the aim of further streamlining the process, a development-free lithographic printing plate precursor that can be mounted on a printing machine as it is and printed without being subjected to development processing after exposure is being researched and developed. For example, various methods are described as a development-free CTP printing plate in Japanese Society of Printing, Vol. 36, pp. 148-163 (1999).

As one of the methods for eliminating the processing step, the exposed printing plate precursor is mounted on the plate cylinder of the printing machine, and the dampening water and the ink are supplied while the plate cylinder is rotated, whereby There is a method called on-press development for removing the unexposed portion of the image forming layer of the original plate. That is, after exposing the printing plate precursor,
This is a method in which it is installed in the printing machine as it is, and the development process is completed during the normal printing start operation. A lithographic printing plate precursor suitable for such on-press development has an image forming layer soluble in dampening water or an ink solvent, and is visible even when developed on a printing machine placed in a bright room. It is necessary to have a suitability for light room handling that does not cause problems such as fogging due to light.

For example, Japanese Patent No. 2938397 discloses that
A lithographic printing plate precursor is described in which a photosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic resin is provided on a hydrophilic support. In this publication, in the lithographic printing plate precursor, infrared laser exposure is carried out to form fine particles of a thermoplastic hydrophobic polymer by heat to coalesce (fuse) to form an image, and then the plate is placed on a plate cylinder of a printing machine. It is described that on-press development can be performed by mounting, supplying dampening water and / or ink. The lithographic printing plate precursor has a light-sensitive region in the infrared region, and thus has suitability for bright room handling. However, in the lithographic printing plate precursor having the image forming layer in which the hydrophobic polymer fine particles are dispersed in the hydrophilic binder resin as described above, when exposed to a high-energy infrared laser, the image formation by the coalescence of the fine particles In addition, there is a problem in that the image forming layer is partially ablated to deteriorate the quality of the printing plate.

On the other hand, in EP 81070,
Providing an image-forming layer in which hydrophobic thermoplastic polymer particles and a photothermal conversion agent are dispersed in a hydrophilic binder on a hydrophilic support, and further providing a water-soluble or water-swellable protective layer made of a hydrophilic resin on the image-forming layer. It is described that the ablation is suppressed by.

In WO98 / 51496, as an anti-ablation method, two image forming layers in which fine particles are dispersed in an aqueous solution-soluble or swellable binder are provided to lower the optical density at the exposure wavelength of the upper layer than that of the lower layer. It is described that the above-mentioned is effective for a lithographic printing plate precursor of a type that is developed in an alkaline aqueous solution or the like after exposure and then mounted on a printing machine.

[0007]

However, even in the planographic printing plate which prevents the above-mentioned ablation,
There were problems such as insufficient printing durability due to insufficient ink receptivity during imprinting, and further improvements were needed.

Therefore, it is an object of the present invention to provide a lithographic printing plate precursor that overcomes the above-mentioned drawbacks of the prior art. That is, it is a lithographic printing plate precursor that can be mounted on a printing machine as it is without performing any processing after infrared scanning exposure based on a digital signal to perform printing, has good on-press developability, and is resistant to stains on printing. It is to provide a lithographic printing plate precursor having high printing durability.

[0009]

DISCLOSURE OF THE INVENTION The present inventor has developed a compound which is insoluble in water and has fluidity at 50 ° C. instead of a hydrophilic binder resin which is usually used, together with a hydrophobic polymer fine particle which is combined by heat and a photothermal conversion agent. When a lipophilic image-forming layer containing a is used, surprisingly good on-press developability was exhibited, and it was found that stain resistance and printing durability are good, and the present invention was completed. It is presumed that the ink solvent contributes to the on-press development that shows good on-press development despite the lipophilic image forming layer. Further, since it is a lipophilic image forming layer that does not contain a hydrophilic binder resin, it is presumed that high printing durability is caused by the fact that the ink receptivity does not deteriorate even during imprinting.
That is, the present invention is as follows.

1. A hydrophilic binder resin containing, on an aluminum substrate having a roughened surface and having a hydrophilic film, fine particles of a hydrophobic polymer that are combined by heat, a photothermal conversion agent, and a compound that is insoluble in water and has fluidity at 50 ° C. A lithographic printing plate precursor comprising a lipophilic image forming layer containing no water and an overcoat layer containing a water-soluble resin thereon.

2. 2. The lithographic printing plate precursor as described in 1 above, wherein the overcoat layer contains at least one fine particle selected from a hydrophobic polymer fine particle and a microcapsule which coalesce by heat.

3. 3. The lithographic printing plate as described in 1 or 2 above, wherein the overcoat layer contains a photothermal conversion agent and the optical density of the overcoat layer at the exposure wavelength is lower than the optical density of the image forming layer at the exposure wavelength. Original version.

4. The substrate is subjected to electrochemical graining treatment in an aqueous solution containing hydrochloric acid and has a thermal conductivity of 0.05 to 0.5.
4. The lithographic printing plate precursor as described in any one of 1 to 3 above, which is a substrate having a hydrophilic film of W / mK.

5. The substrate is subjected to electrochemical graining treatment in an aqueous solution containing hydrochloric acid, and has a density of 1000 to 3200k.
4. The lithographic printing plate precursor as described in any one of 1 to 3 above, which is a substrate having a hydrophilic film having g / m ³ or a porosity of 20 to 70%.

6. The substrate has a roughened small pit having an average opening diameter of 0.01 to 3 μm, a ratio of the average depth of the small pits to the average opening diameter of 0.1 to 0.5, and a thermal conductivity of 0.1. 4. The lithographic printing plate precursor as described in any one of 1 to 3 above, which is a substrate having a hydrophilic film of from 05 to 0.5 W / mK.

7. The substrate has a roughened small pit having an average opening diameter of 0.01 to 3 μm, a ratio of the average depth of the small pits to the average opening diameter of 0.1 to 0.5, and a density of 10
00-3200 kg / m ³ , or porosity 20-70%
4. The lithographic printing plate precursor as described in any one of 1 to 3 above, which is a substrate having a hydrophilic film.

8. The average opening diameter of large undulations on the substrate is 3
The lithographic printing plate precursor as described in any one of 1 to 3 above, wherein

9. 9. The lithographic printing plate precursor as described in any one of 1 to 8 above, wherein the hydrophilic film is an anodized film.

10. 10. The lithographic printing plate precursor as described in 9 above, which has an anodized film amount of 3.2 g / m ² or more.

11. The surface pore size of the anodized film is 40
11. The lithographic printing plate precursor as described in 9 or 10 above, which is not more than nm.

12. 12. The lithographic printing plate precursor as described in any one of 9 to 11 above, wherein the anodic oxide film is subjected to sealing treatment.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. Here,% means mass% unless otherwise specified.

[Image-Forming Layer] The image-forming layer of the present invention contains hydrophobic polymer fine particles which coalesce by heat, a photothermal conversion agent, and a compound which is insoluble in water and has fluidity at 50 ° C.
It is characterized in that it is a lipophilic image forming layer containing no hydrophilic binder resin.

Such hydrophobic polymer particles are preferably thermoplastic hydrophobic polymer particles having a solidification temperature of 35 ° C. or higher, and more preferably 50 ° C. or higher. There is no particular upper limit to the solidification temperature of the thermoplastic hydrophobic polymer particles, but this temperature must be sufficiently lower than the decomposition point of the polymer particles. When the polymer particulates are raised above the solidification temperature, they fuse and coalesce to form hydrophobic agglomerates in the imaging layer. Therefore, these parts become insoluble in water or an aqueous liquid and become ink receptive.

Specific examples of the hydrophobic polymer forming the hydrophobic polymer fine particles used in the present invention include ethylene, styrene, vinyl chloride, methyl (meth) acrylate, ethyl (meth) acrylate, vinylidene chloride and acrylonitrile. Mention may be made of homopolymers or copolymers containing monomers such as, vinylcarbazole or mixtures thereof. Among them, polystyrene and polymethylmethacrylate are particularly preferable.

The weight average molecular weight of the polymer constituting the hydrophobic polymer fine particles of the present invention is 5,000 to 1,000,000.
00, the particle size of the fine particles is preferably 0.01 to 50 μm, more preferably 0.05 to 10 μm, and most preferably 0.05 to 2 μm.

The hydrophobic polymer fine particles of the present invention may have a heat-reactive functional group. As the heat-reactive functional group, an ethylenically unsaturated group that performs a polymerization reaction (for example, an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, etc.), an isocyanate group that performs an addition reaction, or a block thereof and its reaction partner A functional group having a certain active hydrogen atom (for example, an amino group, a hydroxyl group, a carboxyl group, etc.), an epoxy group that also undergoes an addition reaction, and an amino group, a carboxyl group or a hydroxyl group that is a reaction partner thereof, and a carboxyl group that performs a condensation reaction. And a hydroxyl group or an amino group, an acid anhydride that performs a ring-opening addition reaction with an amino group or a hydroxyl group, and a diazonium group that thermally decomposes to react with a hydroxyl group and the like. However, it may be a functional group that performs any reaction as long as a chemical bond is formed.

The polymer fine particles having a heat-reactive functional group used in the image forming layer of the present invention include acryloyl group, methacryloyl group, vinyl group, allyl group, epoxy group, amino group, hydroxyl group, carboxyl group and isocyanate. Mention may be made of those having a group, an acid anhydride and a group protecting them. The introduction of these functional groups into the polymer fine particles may be carried out at the time of polymerization, or by using a polymer reaction after the polymerization.

When introduced at the time of polymerization, it is preferable to emulsion-polymerize or suspension-polymerize these monomers having a heat-reactive functional group. If desired, a monomer having no heat-reactive functional group may be added as a copolymerization component.

Specific examples of the monomer having such a functional group include allyl methacrylate, allyl acrylate, vinyl methacrylate, vinyl acrylate, glycidyl methacrylate, glycidyl acrylate, 2-
Isocyanate Blocked isocyanate with ethyl methacrylate or its alcohol, Blocked isocyanate with 2-isocyanate ethyl acrylate or its alcohol, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid , Methacrylic acid, maleic anhydride, 2
Functional acrylates, bifunctional methacrylates, etc. may be mentioned, but are not limited thereto.

Examples of the monomer which does not have a heat-reactive functional group and is copolymerizable with these monomers include styrene, alkyl acrylate, alkyl methacrylate,
Examples thereof include acrylonitrile and vinyl acetate, but are not limited to these as long as they are monomers having no heat-reactive functional group.

The polymer reaction used when the introduction of the heat-reactive functional group is carried out after the polymerization is, for example, WO96-34.
The polymer reaction described in Japanese Patent No. 316 can be mentioned.

The coagulation temperature of these polymer fine particles having a thermoreactive functional group is preferably 70 ° C. or higher, more preferably 100 ° C. or higher from the viewpoint of stability over time.

The amount of the above hydrophobic polymer fine particles added to the image forming layer is 50% of the solid content of the image forming layer in terms of solid content.
The above is preferable, and 60% or more is further preferable. Within this range, good image formation can be achieved and good printing durability can be obtained.

The image forming layer of the present invention may contain a photothermal conversion agent for converting light into heat in order to enhance sensitivity. The photothermal conversion agent may be any substance that absorbs infrared rays, especially near infrared rays (wavelength 700 to 2000 nm), and various pigments, dyes, and metal fine particles can be used.

For example, Japanese Patent Laid-Open No. 2001-162960,
JP-A No. 11-235883, Journal of the Printing Society of Japan, 38 pages, 35-40 pages (2001), and JP-A 2001-21306.
Pigments, dyes and fine metal particles described in No. 2 are preferably used.

Carbon black is particularly preferred as the pigment. As the metal fine particles, Si, Al, Ti, V, C
r, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr,
Mo, Ag, Au, Pt, Pd, Rh, In, Sn,
Examples thereof include fine particles of W, Te, Pb, Ge, Re and Sb alone or an alloy thereof, or oxides or sulfides thereof. Among them, Re, Sb, Te, Au, Ag, Cu, G
e, Pb and Sn are more preferable, and Ag, Au, Cu,
Sb, Ge and Pb are particularly preferred. The dyes exemplified below are particularly preferable as the dye. However, it is not limited to these.

[0038]

[Chemical 1]

[0039]

[Chemical 2]

[0040]

[Chemical 3]

[0041]

[Chemical 4]

When the photothermal conversion agents of pigments and dyes are added to the image forming layer, the addition ratio is 0.1% of the solid content of the image forming layer.
-50% is preferable, and 3-25% is more preferable. When the metal fine particles are used as the photothermal conversion agent, it is preferably 5% or more of the solid content of the image forming layer, and more preferably 1%.
Used at 0% or more. Good sensitivity is obtained within these ranges.

As the compound which is insoluble in water and has fluidity at 50 ° C., which is contained in the image forming layer of the present invention, for example, ester of acid and polyhydric alcohol or polybasic acid and alcohol or phenol is used. Can be mentioned. A compound having a molecular weight of 1,000 or less is preferable, and specific compounds include 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, and trimethylolpropane. Tris (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate,
Dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, 1,3-butanediol dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate Methacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, bis [p- (3-methacryloyloxy-2-hydroxypropoxy) phenyl] dimethylmethane, bis- [p-
(Methacryloyloxyethoxy) phenyl] dimethylmethane, ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, penta Erythritol diitaconate, sorbitol tetritaconate, tributyl phosphate, trioctyl phosphate,
Examples thereof include tricresyl phosphate.

In the conventional image-forming layer of the type in which hydrophobic polymer particles are combined by heat, hydrophilic binder resins such as gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and its sodium salt, cellulose acetate, alginic acid are used. sodium,
Vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, polymethacrylic acids and their salts, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxy Propyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and hydrates. Hydrolyzed polyvinyl acetate with a degree of decomposition of at least 60%, preferably at least 80% , Polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers, methacrylamide homopolymers and copolymers, N-methylol acrylamide homopolymers and copolymers, etc., but in the present invention, instead of the above, By using a compound which is insoluble in water and has fluidity at 50 ° C., a lipophilic image forming layer is formed. It is presumed that high printing durability can be obtained because the lipophilic image forming layer exhibits good ink receptivity even during imprinting. Further, the lipophilic image forming layer also prevents the image forming layer and the overcoat layer from being mixed with each other during application of the overcoat layer to deteriorate lipophilicity.

The amount of the above water-insoluble and fluid compound added is preferably 3 to 30% of the solid content of the image forming layer, and 5 to 2%.
0% is more preferable. Within this range, good on-press developability and printing durability can be obtained.

If desired, various compounds may be added to the image forming layer of the present invention. For example, after the image exposure, in order to distinguish the image part and the non-image part,
A compound that generates an acid or a radical by heat and a dye that changes color by the acid or the radical can be contained.

As the compound which generates an acid or a radical by heat, for example, US Pat. No. 3,729,313,
No. 4,058,400, No. 4,058,401, No. 4,460,154 and No. 4,921,827, diallyliodonium salts and triallylphosphonium salts, US Pat. No. 3,987, 037, 4,476,2
No. 15, No. 4,826,753, No. 4,619,99
No. 8, No. 4,696,888, No. 4,772,534
No. 4, No. 4,189,323, No. 4,837,128
No. 5,364,734, No. 4,212,970, and the like, and halomethyl-1--3-triazine compounds and halomethyloxadiazole compounds.

As the dye which changes color by an acid or a radical, various dyes such as diphenylmethane type, triphenylmethane type, thiazine type, oxazine type, xanthene type, anthraquinone type, iminoquinone type, azo type and azomethine type dyes are effective. Used.

As a specific example, brilliant green,
Ethyl violet, methyl green, crystal violet, basic fuchsine, methyl violet 2
B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, congo fred, benzopurpurin 4B, α-naphthyl red, nile blue 2B, nile blue A, methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [made by Orient Chemical Industry Co., Ltd.], oil scarlet # 308 [Orient Chemical Industry Co., Ltd.]
Made], Oil Red OG [Orient Chemical Industry Co., Ltd.
Made], Oil Red RR [Orient Chemical Industry Co., Ltd.]
], Oil Green # 502 [produced by Orient Chemical Industry Co., Ltd.], Spiron Red BEH Special [produced by Hodogaya Chemical Industry Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-
4-p-diethylaminophenyliminonaphthoquinone,
2-Carbostearylamino-4-p-dihydrooxyethylamino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4-p-diethylamino Dyes such as phenylimino-5-pyrazolone, p, p ', p "hexamethyltriaminotriphenylmethane (leuco crystal violet), Pergascrip
Examples include leuco dyes such as Blue SRB (manufactured by Ciba Geigy).

A suitable addition amount of the compound generating an acid or radical and the dye discolored by the acid or radical is 0.01 to 10% with respect to the solid content of the image forming layer.

A small amount of a thermal polymerization inhibitor can be added to the image forming layer of the present invention in order to prevent unnecessary thermal polymerization during preparation or storage of the image forming layer coating solution. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,
4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-)
Butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The amount of the thermal polymerization inhibitor added is about 0.01 based on the weight of the entire composition.
-5% is preferable.

If necessary, a higher fatty acid such as behenic acid or behenic acid amide or a derivative thereof is added in order to prevent polymerization inhibition by oxygen, and the surface of the image forming layer is dried in the drying process after coating. May be unevenly distributed. The amount of the higher fatty acid or its derivative added is about 0.1 to about the solid content of the image forming layer.
About 10% is preferred.

Inorganic fine particles may be added to the image forming layer of the present invention. Examples of the inorganic fine particles include silica, alumina,
Suitable examples include magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, and mixtures thereof. These are used for strengthening the film even if it is not light-heat convertible and for strengthening the interfacial adhesion by roughening the surface. be able to.

The average particle size of the inorganic fine particles is 5 nm to 10 μm.
Those having a thickness of 10 nm to 1 μm are more preferable. When the particle size is within this range, both the resin particles and the metal particles of the photothermal conversion agent are stably dispersed in the hydrophilic binder resin, the film strength of the image forming layer is sufficiently retained, and the hydrophilicity that prevents printing stains is excellent. It is possible to form a non-image portion.

Such inorganic fine particles can be easily obtained as a commercial product such as a colloidal silica dispersion. The content of the inorganic fine particles in the image forming layer is preferably 1.0 to 70% of the total solid content of the image forming layer, and more preferably 5.0 to 70%.
50%.

When polymer fine particles having a heat-reactive group are used in the image forming layer of the present invention, a compound which initiates or accelerates these reactions may be added if necessary. Examples of the compound that initiates or accelerates the reaction include compounds that generate a radical or a cation by heat, and examples thereof include a lophine dimer, a trihalomethyl compound, a peroxide, an azo compound, a diazonium salt or a diphenyliodonium salt. And an onium salt, an acylphosphine, an imidosulfonate, and the like.

These compounds account for 1% of the solid content of the image forming layer.
It can be added in the range of up to 20%. Preferably 3
It is in the range of -10%. Within this range, a good reaction initiation or acceleration effect can be obtained without impairing the on-press developability.

The image forming layer of the present invention is prepared by dissolving each of the necessary components described above in a solvent to prepare a coating solution and applying the solution onto the image forming layer. As the solvent used here, ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2.
-Propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N,
N-dimethylformamide, tetramethylurea, N-
Examples thereof include methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone, toluene and water, but are not limited thereto. These solvents are used alone or as a mixture. The solid content concentration of the coating liquid is preferably 1 to 50%.

The coating liquid for the image forming layer of the present invention contains a surfactant for improving the coating property, such as JP-A-62-17.
Fluorine-based surfactants such as those described in No. 0950 can be added. The preferable addition amount is 0.01 to 1% of the total solids of the image forming layer, and more preferably 0.0.
5 to 0.5%.

The dry coating amount of the image forming layer of the present invention varies depending on the use, but is generally preferably 0.5 to 5.0 g / m ² . When the coating amount is less than this range, the apparent sensitivity is high, but the film characteristics of the image forming layer which functions as an image recording are deteriorated. Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating and roll coating.

[Overcoat Layer] The lithographic printing plate precursor of the invention has an overcoat layer containing a water-soluble resin on the image forming layer. With this overcoat layer,
Ablation of the image forming layer during exposure is prevented.

As the water-soluble resin used in the overcoat layer of the present invention, a film formed by coating and drying has a film-forming ability. Specifically, polyvinyl acetate (provided that the hydrolysis rate is 65% or more) is used. ), Acrylic acid homopolymers or copolymers and their alkali metal salts or amine salts, methacrylic acid homopolymers or copolymers and their alkali metal salts or amine salts, acrylamide homopolymers and copolymers, polyhydroxy Ethyl acrylate, N
-Vinylpyrrolidone homopolymer and copolymer, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, 2-acrylamido-2-methyl-1-
Homopolymers or copolymers of propanesulfonic acid and their alkali metal salts or amine salts, gum arabic, fibrin derivatives (for example, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.) and their modified products, white dextrin, pullulan , Enzyme-decomposed etherified dextrin and the like. In addition, two or more kinds of these resins may be mixed and used depending on the purpose.

The overcoat layer may contain at least one fine particle selected from a hydrophobic polymer fine particle and a microcapsule which are coalesced by heat.
By containing such fine particles, printing durability can be further improved.

As the hydrophobic polymer fine particles which are incorporated by heat in the overcoat layer of the present invention, the above-mentioned hydrophobic polymer fine particles suitable for the image forming layer are also suitable.

Microcapsules suitable for the overcoat layer of the present invention are preferably microcapsules containing a compound having a thermoreactive functional group. Suitable heat-reactive functional groups include the same heat-reactive functional groups described above that can be preferably used in the hydrophobic polymer fine particles for the image forming layer of the present invention.

Examples of the compound having a heat-reactive functional group include a polymerizable unsaturated group, a hydroxyl group, a carboxyl group, a carboxylato group or an acid anhydride, an amino group, an epoxy group, and an isocyanate group or a block thereof. Mention may be made of compounds having at least one selected functional group.

As the compound having a polymerizable unsaturated group,
At least one ethylenically unsaturated bond, such as an acryloyl group, a methacryloyl group, a vinyl group or an allyl group.
A compound having one, preferably two or more is preferable, and such a group of compounds is widely known in the industrial field, and in the present invention, these can be used without particular limitation. In chemical form, these are monomers, prepolymers, that is, dimers, trimers and oligomers, mixtures thereof, or copolymers thereof.

Examples include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), their esters and amides, preferably unsaturated carboxylic acids and fats. Esters with group polyhydric alcohols and amides with unsaturated carboxylic acids and aliphatic polyhydric amines are mentioned. Further, an addition reaction product of an unsaturated carboxylic acid ester or unsaturated carboxylic acid amide having a nucleophilic substituent such as a hydroxyl group, an amino group, a mercapto group, and a monofunctional or polyfunctional isocyanate or an epoxide, and a monofunctional Alternatively, a dehydration condensation reaction product with a polyfunctional carboxylic acid is also suitably used.
Further, an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an isocyanate group or an epoxy group,
Monofunctional or polyfunctional alcohols, addition reaction products with amines and thiols, and unsaturated carboxylic acid esters or amides having a leaving group such as a halogen group or a tosyloxy group, and monofunctional or polyfunctional alcohols, amines. And substitution products with thiols are also suitable. Another preferable example is a compound in which the above unsaturated carboxylic acid is replaced with unsaturated phosphonic acid or chloromethylstyrene.

Specific examples of the polymerizable compound which is an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,
3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane tris (acryloyloxypropyl) ether, trimethylolethane Triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate,
Pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate,
Examples thereof include sorbitol pentaacrylate, sorbitol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer and the like.

Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol. Dimethacrylate, hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3- Methacryloyloxy-2 Hydroxypropoxy) phenyl]
Examples thereof include dimethyl methane and bis- [p- (methacryloyloxyethoxy) phenyl] dimethyl methane.

As the itaconic acid ester, ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate,
Examples thereof include 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, and sorbitol tetritaconate.

As the crotonic acid ester, ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate,
Examples thereof include sorbitol tetradicrotonate. Examples of the isocrotonic acid ester include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. As maleic acid ester, ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate,
Examples thereof include sorbitol tetramalate.

Examples of other esters include, for example, Japanese Examined Patent Publication No. 46-27926, Japanese Examined Patent Publication No. 51-47334,
Aliphatic alcohol esters described in JP-A-57-196231, JP-A-59-5240, and JP-A-59-
5241, those having an aromatic skeleton described in JP-A-2-226149, those containing an amino group described in JP-A-1-165613, and the like.

Specific examples of the amide monomer of an aliphatic polyvalent amine compound and an unsaturated carboxylic acid include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Diethylenetriamine tris acrylamide, xylylene bis acrylamide, xylylene bis methacrylamide, etc. can be mentioned. Examples of other preferable amide-based monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

Further, urethane-based addition-polymerizable compounds produced by addition reaction of isocyanate and hydroxyl group are also suitable, and specific examples thereof include, for example, Japanese Examined Patent Publication No.
In a molecule obtained by adding an unsaturated monomer having a hydroxyl group represented by the following formula (I) to a polyisocyanate compound having two or more isocyanate groups in one molecule described in JP-A-8-41708, Examples thereof include urethane compounds containing one or more polymerizable unsaturated groups.

General formula (I) CH ₂ ═C (R ¹ ) COOCH ₂ CH (R ² ) OH (wherein R ¹ and R ² represent H or CH ₃ ).

Further, a urethane acrylate as described in JP-A-51-37193, JP-B-2-32293 and JP-B-2-16765, and JP-B-58-4.
9860, Japanese Patent Publication No. 56-17654, Japanese Patent Publication No. 62-
Urethane compounds having an ethylene oxide skeleton described in 39417 and JP-B-62-39418 are also preferred.

Further, radical-polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909 and JP-A-1-105238 are preferable. Can be mentioned as.

Other preferable examples include polyester acrylates and epoxies as described in JP-A-48-64183, JP-B-49-43191 and JP-A-52-30490. Examples thereof include polyfunctional acrylates and methacrylates such as epoxy acrylates obtained by reacting a resin with (meth) acrylic acid. Also, Japanese Patent Publication No. 46-43946,
Specific unsaturated compounds described in JP-B-1-40337 and 1-40336, vinylphosphonic acid compounds described in JP-A-2-25493, and the like can also be mentioned as preferable examples. Further, in some cases, a compound containing a perfluoroalkyl group described in JP-A-61-22048 is also suitably used. Furthermore, Journal of Japan Adhesion Society, Vol. 20, No. 7, pp. 300-308 (198
Those introduced as photocurable monomers and oligomers in 4 years) can also be preferably used.

Suitable epoxy compounds include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, bisphenols or polyphenols or hydrogenated products thereof. Examples thereof include polyglycidyl ether.

Suitable isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexane phenylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, or alcohols thereof. Alternatively, a compound blocked with an amine can be used.

Suitable amine compounds include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine and polyethyleneimine.

Examples of suitable compounds having a hydroxyl group include compounds having a terminal methylol group, polyhydric alcohols such as trimethylolpropane and pentaerythritol, bisphenols and polyphenols.

Preferred compounds having a carboxyl group include aromatic polycarboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polycarboxylic acids such as adipic acid.

Suitable compounds having a hydroxyl group or a carboxyl group include, in addition to the above compounds, for example, JP-B-54.
-19773, 55-34929, 57-43.
It is also possible to use the compound known as the binder for the existing PS plate described in JP-A-890.

Suitable acid anhydrides include pyromellitic acid anhydride, benzophenonetetracarboxylic acid anhydride and the like.

A preferred copolymer of ethylenically unsaturated compounds is a copolymer of allyl methacrylate. Examples thereof include allyl methacrylate / methacrylic acid copolymers, allyl methacrylate / ethyl methacrylate copolymers, allyl methacrylate / butyl methacrylate copolymers.

The diazo resin is preferably a diazodiphenylamine / formalin condensation resin hexafluorophosphate or an aromatic sulfonate.

As a method of microencapsulation, a known method can be applied. For example, as a method for producing microcapsules, US Pat.
No. 458, method utilizing coacervation, British Patent 990443, US Pat. No. 3,287,154.
Nos. 38-19574, 42-446, and 42-711, the interfacial polymerization method, US Pat. Nos. 3,418,250 and 3,660,304, the method by polymer precipitation, US Pat. No. 3,796,669. Urea-formaldehyde-based or urea formaldehyde-resorcinol-based found in U.S. Pat. Nos. 4,001,140,4087,376 and 4,089,802. Method of using wall forming materials, US Patent 402
No. 5445, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, Japanese Patent Publication No. 36-9163, No. 51-9079, in-situ method by monomer polymerization, British Patent 9304.
No. 22, U.S. Pat. No. 3,111,407, spray drying method, British Patents 952807, 967074.
However, the method is not limited to these.

The preferred microcapsule wall used in the present invention has three-dimensional cross-linking and has a property of being swollen by a solvent. From this point of view, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, or a mixture thereof, and particularly preferably polyurea and polyurethane. A compound having a thermoreactive functional group may be introduced into the microcapsule wall.

The average particle size of the above microcapsules is
0.01 to 20 μm is preferable, 0.05 to 2.0 μm
Is more preferable, and 0.10 to 1.0 μm is particularly preferable. If the average particle size is too large, the resolution will be poor, and if it is too small, the stability over time will be poor.

In such microcapsules, the capsules may or may not be coalesced by heat. The point is that, among the microcapsule-encapsulated substances, those that exude to the surface of the capsule, the wall of the microcapsule, or the outside of the microcapsule may cause a chemical reaction by heat. It may react with the added water-soluble resin or the added low molecular weight compound. In addition, two or more types of microcapsules may be provided with functional groups capable of thermally reacting with different functional groups, so that the microcapsules may react with each other. Therefore, it is preferable for image formation that the microcapsules are melted and coalesced by heat, but it is not essential.

From the viewpoint of further improving printing durability, the amount of the above-mentioned hydrophobic polymer particles and / or microcapsules added to the overcoat layer is preferably 50% or more, and more preferably 60% or more. More preferable.

The overcoat layer of the present invention may contain a photothermal conversion agent. As a suitable photothermal conversion agent,
The photothermal conversion agent which can be used for an image forming layer can be mentioned. Among them, a dye having a water-soluble group is more preferable. As a specific example, the photothermal conversion agents IR-1 to IR-11 described above.
But is not limited to these.

In the present invention, the optical density of the overcoat layer at the exposure wavelength is preferably lower than the optical density of the image forming layer at the same wavelength. Under this optical density condition, a good image can be formed on the image forming layer.

Further, for the purpose of ensuring coating uniformity, a nonionic surfactant such as polyoxyethylene nonylphenyl ether or polyoxyethylene dodecyl ether is added to the overcoat layer in the case of coating with an aqueous solution. be able to.

The dry coating amount of the overcoat layer was 0.1.
˜2.0 g / m ² is preferred. Within this range, good ablation can be prevented without impairing the on-press developability.

[Aluminum Substrate] As the lithographic printing plate precursor of the present invention, an aluminum substrate which has been roughened and has a hydrophilic film is used. Hereinafter, such an aluminum substrate will be described in detail.

The aluminum plate used as a raw material for the aluminum substrate of the present invention is a dimensionally stable metal whose main component is aluminum, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, or a plastic film or paper on which aluminum or an aluminum alloy is laminated or vapor-deposited can be used. Further, a composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-B-48-18327 can be used.

As a method of manufacturing the above aluminum plate,
For example, a DC casting method, a method in which soaking and / or annealing treatment is omitted from the DC casting method, and a continuous casting method can be mentioned. In the following description, the above-mentioned substrates made of aluminum or aluminum alloy will be generically referred to as aluminum substrates.

The different elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium, and the content of the different elements in the alloy is 10% or less. is there. In the present invention, it is preferable to use a pure aluminum plate, but since completely pure aluminum is difficult to produce due to refining technology,
You may use the thing containing a little foreign element. As described above, the aluminum plate applied to the present invention is not specified in its composition, and is made of a conventionally publicly known material described in Aluminum Handbook 4th Edition (Light Metals Association (1990)), for example, JIS. A 1050, J
IS A 1100, JIS A 3103, JIS
A 3005 and the like can be appropriately used.

The aluminum plate used in the present invention has a thickness of about 0.1 to 0.6 mm. This thickness can be appropriately changed according to the size of the printing machine, the size of the printing plate, and the wishes of the user. The surface treatment described below is appropriately applied to the aluminum plate.

Generally, an aluminum substrate for a lithographic printing plate includes a degreasing process for removing rolling oil adhering to the aluminum plate, a pre-roughening process such as a desmutting process for dissolving smut on the surface of the aluminum plate, and an aluminum plate. It is manufactured through a roughening treatment step of roughening the surface of.

After the above treatment, the aluminum plate of the present invention is further provided with a hydrophilic film having a specific thermal conductivity.
Further, if necessary, an acid / alkali treatment step, a sealing treatment step, and a hydrophilic treatment step are performed to form a substrate for a lithographic printing plate precursor. Further, if necessary, an undercoat layer may be provided after forming the substrate for a lithographic printing plate precursor.

The production method including the surface-roughening treatment of the present invention may be a continuous method or an intermittent method, but it is industrially preferable to use the continuous method. Hereinafter, each surface treatment step will be described in detail.

<Pre-roughening Treatment> The aluminum plate is subjected to dissolution treatment using an alkaline aqueous solution such as caustic soda to remove strong dirt and natural oxide film, and the residual alkali components after the dissolution treatment are removed. In order to neutralize, it is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, collomic acid, or a mixed acid thereof to carry out the neutralization treatment. If necessary, in order to remove oils and fats, rust, dust and the like on the surface of the aluminum plate, solvent degreasing with trichlene, thinner or the like, or emulsion degreasing treatment with an emulsion of kerosene, triethanol or the like may be carried out. It is particularly preferable that the type and composition of the acid used in the neutralization treatment are matched to those of the acid used in the electrochemical graining treatment in the next step.

<Roughening treatment> The roughening treatment of the aluminum plate surface is carried out by various methods. For example, there may be mentioned a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, a method of chemically selectively dissolving the surface, and a combination of these methods.

As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. As a chemical method, Japanese Patent Laid-Open No.
A method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in 4-31187 is suitable. Further, as an electrochemical graining method, there is a method of performing alternating current or direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid.
Also, an electrolytic surface roughening method using a mixed acid as disclosed in JP-A-54-63902 can be used. Among these, electrochemical surface roughening treatment using an aqueous solution containing hydrochloric acid as an electrolytic solution is particularly preferable.

In the case of the electrochemical graining treatment using an electrolytic solution mainly containing hydrochloric acid, the average opening diameter is 0.01 to several μm.
m, a small pit having a depth-to-average opening diameter ratio of 0.1 to 0.5 is formed, and at the same time, the average opening diameter is several μm to several tens of μ.
Since a double structure having a large m undulation is likely to be formed, a roughened shape desired for stain resistance and printing durability can be obtained. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid and the like can be added to the electrolytic solution, and acetic acid is particularly preferable.

In the electrochemical graining treatment, the applied voltage is preferably 1 to 50V, more preferably 5 to 30V. Current density (peak value) is 5 to 200 A / dm ²
Is preferred, and 20 to 150 A / dm ² is more preferred. Electricity is 10 to 2000C in total for all processing steps
/ Dm ² is preferable, and 200 to 1000 C / dm ² is more preferable. The temperature is preferably 10 to 60 ° C., and 15 to 4
5 ° C. is more preferable. The frequency is preferably 10 to 200 Hz, more preferably 40 to 150 Hz.

The hydrochloric acid concentration is preferably 0.1 to 5%, and the current waveform used for electrolysis is appropriately selected according to the desired roughening shape such as sine wave, rectangular wave, trapezoidal wave, sawtooth tooth, etc. Square waves are preferred.

The aluminum plate subjected to the electrochemical surface roughening treatment is immersed in an acid or alkali aqueous solution for surface etching treatment in order to remove surface smut and the like and to control the rough surface pit shape. Done. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid,
It includes hydrochloric acid and the like, and examples of the alkali include sodium hydroxide, potassium hydroxide and the like. Among these, it is preferable to use an aqueous alkali solution, and use an aqueous solution of 0.05 to 40% of the alkali at 20 to 90 ° C.
It is preferable to perform the treatment at the solution temperature of 5 seconds to 5 minutes, and after surface etching with the alkaline aqueous solution with the alkaline aqueous solution, immersing it in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof. Sum processing is performed.

As the electrolytic device used in the surface roughening treatment step, known electrolytic devices such as a vertical type, a flat type and a radial type can be used, but the radial type as described in JP-A-5-195300 is used. An electrolysis device is particularly preferred.

FIG. 1 is a schematic view of a radial type electrolysis device preferably used in the present invention. In FIG. 1, in the radial type electrolysis apparatus, an aluminum plate 11 is wound around a radial drum roller 12 arranged in a main electrolysis tank 21, and main electrodes 13a and 13b connected to an AC power source 20 in a conveying process.
Electrolyzed by. The acidic aqueous solution 14 passes from the solution supply port 15 through the slit 16 to the solution passage 17 between the radial drum roller 12 and the main poles 13a and 13b.
Is supplied to.

Then, the aluminum plate 11 treated in the main electrolytic bath 21 is subjected to electrolytic treatment in the auxiliary anode bath 22. In this auxiliary anode tank 22, the auxiliary anode 18 is the aluminum plate 1
1, and the acidic aqueous solution 14 is supplied so as to flow between the auxiliary anode 18 and the aluminum plate 11. The current flowing through the auxiliary electrode is the thyristor 19a.
And 19b.

The main electrodes 13a and 13b can be selected from carbon, platinum, titanium, niobium, zirconium, stainless steel, an electrode used for a fuel cell cathode, etc., but carbon is particularly preferable. As the carbon, generally commercially available impermeable graphite for chemical devices, resin-containing graphite and the like can be used. The auxiliary anode 18 can be selected from known oxygen generating electrodes such as ferrite, iridium oxide, platinum, or platinum clad or plated on a valve metal such as titanium, niobium, or zirconium.

The supply direction of the hydrochloric acid-containing aqueous solution passing through the main electrolytic bath 21 and the auxiliary anode bath 22 may be parallel to that of the aluminum plate 11 or may be a counter. The relative flow rate of the hydrochloric acid-containing aqueous solution to the aluminum plate is 10 to 100.
It is preferably 0 cm / sec.

One or more AC power sources can be connected to one electrolysis device. Also, two or more electrolysis devices may be used, and the electrolysis conditions in each device may be the same or different. Further, after the electrolytic treatment is completed, it is preferable to perform draining with a nip roller and washing with water by spraying in order to prevent the treatment liquid from being taken out to the next step.

Further, in the above-mentioned surface roughening treatment, for example, the conductivity of the hydrochloric acid-containing aqueous solution (i) and (ii) Based on the concentrations of hydrochloric acid and aluminum ions determined from the propagation velocity of sound waves and (iii) temperature, hydrochloric acid and water were added while adjusting the addition amount, and a hydrochloric acid-containing aqueous solution of the same amount as the addition volume of hydrochloric acid and water was added. It is preferable to keep the concentration of the hydrochloric acid-containing aqueous solution constant by overflowing the electrolytic solution from the electrolysis device and discharging it.

Further, in the present invention, a pause time of 0.2 to 10 seconds is provided in the course of the electrochemical graining treatment in the hydrochloric acid-containing electrolytic solution, and the electrochemical graining treatment is performed once. It is an essential requirement that the amount of electricity is less than 100 C / dm ² . When the electrochemical surface roughening treatment is carried out in a plurality of times as described above, when the rest time is less than 0.2 seconds and the amount of electricity in the electrochemical surface roughening treatment exceeds 100 C / dm ^2. However, it is not possible to suppress the formation of coarse pits having an opening diameter of more than 20 μm, and if the pause time exceeds 10 seconds, it takes too much time to manufacture the aluminum substrate, and the productivity deteriorates.

The above-described electrochemical graining treatment using an aqueous solution containing hydrochloric acid as an electrolytic solution may be used in combination with mechanical graining treatment or electrochemical graining treatment under different conditions.

The mechanical surface roughening treatment is preferably carried out before the electrochemical surface roughening treatment and prior to the dissolution treatment using the alkaline aqueous solution. The method of mechanical surface roughening treatment is not particularly limited, but brush polishing and honing polishing are preferable.
In brush polishing, for example, a cylindrical brush having bristles of 0.2 to 1 mm in diameter is rotated, and a slurry in which an abrasive is dispersed in water is supplied to the contact surface and pressed against the surface of an aluminum plate to roughen the surface. Perform processing. In the honing polishing, a slurry in which an abrasive is dispersed in water is injected from a nozzle under pressure, and the slurry is made to collide obliquely with the surface of an aluminum plate for roughening treatment. Further, mechanical roughening treatment can also be performed by laminating a sheet which has been roughened in advance on the surface of the aluminum plate and applying pressure to transfer the roughened surface pattern.

When performing the mechanical surface roughening treatment, the solvent degreasing treatment or the emulsion degreasing treatment can be omitted.

Examples of the electrochemical graining treatment under different conditions include an electrochemical graining treatment mainly containing nitric acid. The acidic aqueous solution containing nitric acid as a main component may be one that is used for an electrochemical roughening treatment using a usual direct current or alternating current. For example, one or more nitric acid compounds such as aluminum nitrate, sodium nitrate, and ammonium nitrate are added to a nitric acid aqueous solution having a nitric acid concentration of 5 to 15 g / l at a concentration from 0.01 g / l to saturation. be able to. Metals and the like contained in aluminum alloys such as iron, copper, manganese, nickel, titanium, magnesium and silicon may be dissolved in the acidic aqueous solution containing nitric acid as a main component.

The acidic aqueous solution containing nitric acid as a main component contains, among others, nitric acid, an aluminum salt, and a nitrate.
And, aluminum ion is 1 to 15 g / l, preferably 1 to 10 g / l, and ammonium ion is 10 to 300.
It is preferable to use a product obtained by adding aluminum nitrate and ammonium nitrate to a nitric acid aqueous solution having a nitric acid concentration of 5 to 15 g / l so that the concentration becomes ppm. The aluminum ions and ammonium ions spontaneously increase during the electrochemical graining treatment. The liquid temperature at this time is preferably 10 to 95 ° C, and more preferably 40 to 80 ° C.

In the lithographic printing plate precursor of the invention which has been subjected to the above-mentioned roughening treatment, the average opening diameter of the small pits having the roughened shape is preferably 0.01 to 3 μm. More preferably 0.05
˜2 μm, particularly preferably 0.05 to 1.0 μm. If it is less than 0.01 μm, satisfactory stain resistance and printing durability cannot be ensured during printing. On the other hand, if it exceeds 3 μm, the printing durability is deteriorated.

The ratio of the average depth of the small pits to the average opening diameter is preferably 0.1 to 0.5. It is more preferably 0.1 to 0.3, and particularly preferably 0.15 to 0.2. If it is less than 0.1, the stain resistance and printing durability during printing deteriorate, while if it exceeds 0.5, the stain resistance deteriorates.

The average opening diameter of the undulations having a roughened shape is preferably 3 to 20 μm. More preferably 3 to 17 μm
And particularly preferably 4 to 10 μm. If it is less than 3 μm, the stain resistance and printing durability during printing deteriorate. On the other hand, 20μ
If it exceeds m, there arises a problem that the stain resistance is deteriorated.

<Formation of Hydrophilic Film> The aluminum substrate of the present invention has a thermal conductivity of 0.05 on the aluminum plate which has been subjected to the surface roughening treatment as described above and, if necessary, other treatments.
It is characterized in that a hydrophilic film of 0.5 W / mK is provided.

The hydrophilic film has a thermal conductivity of 0.05 in the film thickness direction.
W / (m · K) or more, preferably 0.08 W /
(M · K) or more, and 0.5 W / (m · K) or less, preferably 0.3 W / (m · K) or less, and more preferably 0.2 W / (m · K). ) Below.
Thermal conductivity in the film thickness direction is 0.05 to 0.5 W / (mK)
Then, the heat generated in the image forming layer due to the exposure of the laser beam can be prevented from diffusing into the substrate. As a result, the sensitivity is increased, the efficiency of heat fusion of the fine particles is increased, the image strength is improved, and the printing durability can be improved.

The thermal conductivity in the film thickness direction of the hydrophilic film specified in the present invention will be described below. Various methods have been reported so far for measuring the thermal conductivity of thin films. 19
In 1986, ONO et al. Reported the thermal conductivity in the planar direction of a thin film using a thermograph. An attempt to apply the AC heating method to the measurement of thermophysical properties of thin films has also been reported.
The origin of the AC heating method can be traced back to the report of 1863, but in recent years, various measurement methods have been proposed by developing a heating method using a laser and combining with a Fourier transform. A device using the laser angstrom method is actually commercially available. In all of these methods, the thermal conductivity in the plane direction (in-plane direction) of the thin film is obtained.

However, when considering the heat conduction of a thin film, heat diffusion in the depth direction is an important factor. It is said that the thermal conductivity of a thin film is not isotropic as reported variously, and particularly in the case of the present invention, it is extremely important to directly measure the thermal conductivity in the film thickness direction. From such a viewpoint, a method using a thermocomparator is a method using Lambropo as an attempt to measure the thermophysical properties of the thin film in the film thickness direction.
ulos et al. (J. Appl. Phys., 66.
(9) (1 November 1989)) and He
by Nager et al. (APPLIED OPTICS,
Vol. 32, No. 1 (1 January 199
3)). Furthermore, in recent years, Hashimoto et al. Reported a method for measuring the thermal diffusivity of a polymer thin film by temperature wave thermal analysis applying Fourier analysis (Net.
su Sokutei, 27 (3) (2000)).

The thermal conductivity in the film thickness direction of the hydrophilic film defined in the present invention is measured by the method using the above thermo-comparator. Hereinafter, the above method will be described in detail, but the basic principle of the above method will be described with reference to Lambpropo described above.
It is described in detail in the article by ulos et al. and the article by Henager et al. The apparatus used in the above method is
It is not limited to the following device.

FIG. 2 is a schematic diagram of a thermocomparator 30 that can be used for measuring the thermal conductivity in the film thickness direction of the hydrophilic film of the lithographic printing plate precursor according to the present invention. The method using a thermocomparator is greatly affected by the contact area with the thin film and the state (roughness) of the contact surface. Therefore, it is important to make the tip of the thermocomparator 30 in contact with the thin film as small as possible. For example, a chip (wire material) 31 made of oxygen-free copper and having a minute tip with a radius r ₁ = 0.2 mm is used.

This chip 31 is fixed to the center of a constantan reservoir 32, and the periphery of the reservoir 32 is
An oxygen-free copper heating jacket 34 having an electric heater 33 is fixed. The heating jacket 34 is heated by the electric heater 33, and the output of the thermocouple 35 mounted inside the reservoir 32 is fed back to the reservoir 3
When the temperature is controlled to be 60 ± 1 ℃, the chip 31 becomes 60
Heated to ± 1 ° C. On the other hand, radius 10 cm, thickness 10 m
A heat sink 36 made of oxygen-free copper of m is prepared, and a metal substrate 38 having a film 37 to be measured is placed on the heat sink 36. The temperature of the surface of the heat sink 36 is measured using a contact thermometer 39.

After the thermo-comparator 30 is set in this way, the tip of the heated chip 31 is brought into close contact with the surface of the film 37. Thermo comparator 30
Is attached, for example, to the tip of a dynamic micro hardness tester instead of an indenter and is driven up and down.
The chip 31 hits the surface of and is pressed until a load of 0.5 mN is applied. As a result, the variation in the contact area between the film 37 to be measured and the chip 31 can be minimized.

When the heated chip 31 is brought into contact with the film 37, the tip temperature of the chip 31 decreases, but reaches a steady state at a certain constant temperature. This is because the amount of heat given to the chip 31 from the electric heater 33 through the heating jacket 34 and the reservoir 32 and the amount of heat diffused from the chip 31 to the heat sink 36 through the metal base 38 are balanced. At this time, the tip temperature, the heat sink temperature, and the reservoir temperature are respectively recorded as the tip temperature recorder 40,
Heat sink temperature recorder 41 and reservoir temperature recorder 4
Record using 2.

The relationship between each of the above temperatures and the thermal conductivity of the film is expressed by the following equation (1).

[0139]

[Equation 1]

However, the symbols in the above equation (1) are as follows. T _t : chip tip temperature, T _b : heat sink temperature, T
_r : reservoir temperature, K _tf : film thermal conductivity, K ₁ : reservoir thermal conductivity, K ₂ : chip thermal conductivity (400 W / in the case of oxygen-free copper)
(M · K)), the case without the K ₄ :( coating) metal substrate thermal conductivity, r _1: the tip end curvature radius, A _2: contact area between the reservoir and the chip, A _3: a chip and the film Contact area, t: film thickness, t ₂ : contact thickness (≈0)

By changing the film thickness (t), each temperature (T _t , T
By measuring and plotting _b and T _r ), the slope of the above formula (1) can be obtained and the film thermal conductivity (K _tf ) can be obtained. That is, this slope is, as is clear from the above formula (1), the reservoir thermal conductivity (K ₁ ), the tip radius of curvature (r ₁ ), the film thermal conductivity (K _tf ), and the contact between the chip and the film. It is a value determined by the area (A ₃ ),
Since K ₁ , r ₁ and A ₃ are known values, the value of K _tf can be obtained from the slope.

The present inventors determined the thermal conductivity of the anodic oxide film (Al ₂ O ₃ ) provided on the aluminum substrate using the above measuring method. The temperature was measured while changing the film thickness, and the thermal conductivity of Al ₂ O ₃ obtained from the slope of the resulting graph was 0.69 W / (m · K). This is in good agreement with the results of the above-mentioned Lambropoulos et al. This result shows that the thermophysical property value of the thin film is the bulk thermophysical property value (the thermal conductivity of the bulk Al ₂ O ₃ is 2
It also shows that it is different from 8 W / (mK).

When the above method is used for measuring the thermal conductivity in the film thickness direction of the hydrophilic film of the lithographic printing plate precursor of the present invention, the tip of the chip is made fine and the pressing load is kept constant, A surface roughened for a lithographic printing plate is also preferable because it is possible to obtain a consistent result. It is preferable that the value of the thermal conductivity is measured at a plurality of different points on the sample, for example, 5 points, and the average value thereof is obtained.

The film thickness of the hydrophilic film is preferably 0.1 μm or more, and 0.3 μm, in terms of scratch resistance and printing durability.
m or more is more preferable, and 0.6 μm or more is particularly preferable. From the viewpoint of manufacturing cost, in view of the fact that a large amount of energy is required to provide a thick film, it is 5 μm or less. Preferably 3 μm
The thickness is more preferably below, and particularly preferably 2 μm or below.

The hydrophilic film of the present invention has a density of 1000 from the viewpoint of the effect on the heat insulating property, the film strength and the stain resistance during printing.
It is preferably ˜3200 kg / m ³ .

As a method for measuring the density, for example, from the weight measurement by the Mason method (the anodic oxide film weight method by dissolving the chromic acid / phosphoric acid mixture solution) and the film thickness obtained by observing the cross section by SEM, It can be calculated by a formula.

Density (kg / m ³ ) = (weight of hydrophilic film per unit area / film thickness)

The density of the formed hydrophilic film is 1000 kg / m.
^If it is less than ³ , the film strength will be low, which may adversely affect the image forming properties and printing durability, and the stain resistance during printing will also deteriorate. If it exceeds 3200 kg / m ³ , sufficient heat insulation cannot be obtained, and the effect of improving sensitivity decreases.

In the present invention, the porosity of the hydrophilic film is 20.
˜70% is preferable, 30 to 60% is more preferable, and 40 to 50% is particularly preferable.
If the porosity of the hydrophilic film is less than 20%, the thermal diffusion to the aluminum substrate cannot be sufficiently suppressed, and the effects of increasing the sensitivity and improving the printing durability are insufficient. When the porosity exceeds 70%, the problem of stains on the non-image area is likely to occur.

The method for providing the hydrophilic film is not particularly limited, and an anodic oxidation method, a vapor deposition method, a CVD method, a sol-gel method, a sputtering method, an ion plating method, a diffusion method or the like can be appropriately used. Alternatively, a method of applying a solution in which hollow particles are mixed with a hydrophilic resin or a sol-gel solution can be used.

Among them, it is most preferable to use a treatment for forming an oxide by an anodizing method, that is, an anodizing treatment. The anodizing treatment can be performed by a method conventionally used in this field. Specifically, when a direct current or an alternating current is applied to the aluminum plate in an aqueous solution or a non-aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., alone or in combination of two or more. An anodized film, which is a hydrophilic film, can be formed on the surface of the aluminum plate.

The conditions of the anodizing treatment cannot be unconditionally determined because they vary depending on the electrolytic solution used, but generally the electrolytic solution concentration is 1 to 80%, the liquid temperature is 5 to 70 ° C., and the current density is 0. Appropriately, 0.5 to 60 A / dm ² , voltage 1 to 200 V, and electrolysis time 1 to 1000 seconds.

Among these anodizing treatments, the method of anodizing treatment at a high current density in a sulfuric acid electrolytic solution described in British Patent No. 1,412,768 and US Pat. No. 3,511,511 The method described in No. 661, in which phosphoric acid is used as an electrolytic bath and anodizing treatment is preferable. Also,
It is also possible to perform a multi-stage anodizing treatment such as anodizing in sulfuric acid and further anodizing in phosphoric acid.

In the present invention, the anodic oxide film preferably has a sensitivity of 3.2 g / m ² or more, more preferably 4.0 g / m ² or more, and more preferably 5 g / m ² or more.
It is particularly preferably at least g / m ² , and considering that a large amount of energy is required to form a thick film, it is preferably at most 50 g / m ² ,
and more preferably at g / m ² or less, and particularly preferably 20 g / m ² or less.

On the surface of the anodic oxide film, fine recesses called micropores are formed uniformly distributed. The diameter density of the micropores present in the anodized film is
It can be adjusted by appropriately selecting the processing conditions. By increasing the diameter density of the micropores, the thermal conductivity in the film thickness direction of the anodized film is 0.05 to 0.5W.
It can be / (m · K).

Further, by increasing the micropore diameter density of the anodized film, the density becomes 1000 to 3200 kg.
/ M can ³ to be.

In the present invention, it is preferable to carry out a pore widening treatment for expanding the pore diameter of the micropores after the anodizing treatment for the purpose of lowering the thermal conductivity and density or increasing the porosity. In the pore widening treatment, the aluminum substrate having the anodized film formed thereon is immersed in an acid aqueous solution or an alkaline aqueous solution to dissolve the anodized film and expand the pore size of the micropores. In the pore widening treatment, the dissolved amount of the anodized film is preferably 0.01 to 2
0 g / m ^2, more preferably 0.1-5 g / m ^2, particularly preferably at a range of a 0.2~4g / m ^2.

The pore diameter of the micropores is preferably 0 to 40 nm from the viewpoint of print stains and on-machine development. The thickness is more preferably 15 nm or less, and particularly preferably 7 nm or less. Within this range, good print stain and on-press developability can be obtained. Further, from the viewpoint of sensitivity and printing durability, the pore diameter at a position 0.4 μm lower from the surface is 7 to 200 n.
m is preferred. The thickness is more preferably 15 to 100 nm, and particularly preferably 30 to 100 nm. Within this range, good heat insulation can be obtained, and the effects of improving sensitivity and printing durability can be obtained.

When an acid aqueous solution is used for the pore widening treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid or a mixture thereof. The concentration of the aqueous acid solution is preferably 10 to 1000 g / l, and 20 to
More preferably, it is 500 g / l. The temperature of the aqueous acid solution is preferably 10 to 90 ° C, more preferably 30 to 70 ° C. The immersion time in the acid aqueous solution is 1 to
It is preferably 300 seconds, more preferably 2 to 100 seconds.

On the other hand, when an alkaline aqueous solution is used for the pore widening treatment, it is preferable to use at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The alkaline aqueous solution preferably has a pH of 10 to 13.
It is more preferably from 1.5 to 13.0. The temperature of the alkaline aqueous solution is preferably 10 to 90 ° C., and 30
More preferably, it is -50 ° C. The immersion time in the alkaline aqueous solution is preferably 1 to 500 seconds, and 2 to 1
More preferably, it is 00 seconds.

Further, the hydrophilic film may be an inorganic film provided by a sputtering method, a CVD method or the like in addition to the above-mentioned anodic oxide film. Examples of the compound forming the inorganic film include oxides, nitrides, silicides, borides, and carbides. Further, the inorganic film may be composed of only a single compound, or may be composed of a mixture of compounds.

Specific examples of the compound constituting the inorganic film include aluminum oxide, silicon oxide, titanium oxide,
Zirconium oxide, hafnium oxide, vanadium oxide,
Niobium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, chromium oxide; aluminum nitride, silicon nitride, titanium nitride, zirconium nitride, hafnium nitride, vanadium nitride, niobium nitride, tantalum nitride, molybdenum nitride. , Tungsten nitride, chromium nitride, silicon nitride, boron nitride; titanium silicide,
Zirconium silicide, hafnium silicide, vanadium silicide, niobium silicide, tantalum silicide, molybdenum silicide, tungsten silicide, chromium silicide; titanium boride, zirconium boride, hafnium boride, vanadium boride, boride Niobium, tantalum boride, molybdenum boride, tungsten boride, chromium boride; aluminum carbide, silicon carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, chromium carbide Is mentioned.

<Sealing Treatment> In the present invention, in order to improve the stain resistance and the on-press developability of the lithographic printing plate substrate of the present invention obtained by providing the hydrophilic film as described above, Sealing treatment may be performed. The sealing treatment used in the present invention can be carried out by a conventionally known method, but in order to achieve both sensitivity, printing durability and stain resistance, and on-press developability, it is necessary to use the fine pores of the sealing treatment film. The opening diameter is 0-40 in the surface layer
nm, 7 to 200 nm at a position 0.4 μm below the surface layer
Is preferred.

The sealing treatment used in the present invention is described in JP-A-4-176690 and Japanese Patent Application No. 10-1068.
The sealing treatment of the anodized film with pressurized steam or hot water described in Japanese Patent No. 19 (JP-A No. 11-301135) is mentioned. Also, silicate treatment, dichromate aqueous solution treatment, nitrite treatment, ammonium acetate treatment, electrodeposition sealing treatment, triethanolamine treatment, barium carbonate treatment, hot water treatment containing a trace amount of phosphate. It can also be carried out using a known method such as. Among them, particularly preferable is an average particle size of 8 to 800 nm described in Japanese Patent Application No. 2001-9871.
A sealing treatment using particles of

The pore-sealing treatment using particles has an average particle size of 8 to 8
00 nm, preferably 10-500 nm average particle size, more preferably 10-150 nm average particle size. Within this range, there is little risk that particles will enter the inside of the micropores present in the hydrophilic film, the effect of high sensitivity can be sufficiently obtained, and the adhesiveness with the image forming layer will be sufficient, resulting in printing durability. Will be excellent. The thickness of the particle layer is preferably 8 to 800 nm, and 10 to 50 nm.
More preferably, it is 0 nm.

The particles used in the present invention have a thermal conductivity of 6
It is preferably 0 W / (m · K) or less, and 40 W /
It is more preferably (m · K) or less, and 0.3 to 10
It is particularly preferably W / (m · K) or less. When the thermal conductivity is 60 W / (m · K) or less, the thermal diffusion to the aluminum substrate is sufficiently suppressed, and the effect of increasing the sensitivity is sufficiently obtained.

As the method for providing the particle layer, for example, dipping treatment with a solution, spraying treatment, coating treatment,
Electrolytic treatment, vapor deposition treatment, sputtering, ion plating, thermal spraying, plating and the like can be mentioned, but not limited thereto.

For the electrolytic treatment, direct current or alternating current can be used. Examples of the waveform of the alternating current used for the electrolytic treatment include a sine wave, a rectangular wave, a triangular wave, and a trapezoidal wave. The frequency of the alternating current is preferably 30 to 200 Hz, and more preferably 40 to 120 Hz, from the viewpoint of the cost of manufacturing the power supply device. When a trapezoidal wave is used as the waveform of the alternating current, the time tp until the current reaches the peak from 0 is 0.1 to 2 mse.
c is preferable, and 0.3 to 1.5 msec is more preferable. If the tp is less than 0.1 msec, the impedance of the power supply circuit influences, a large power supply voltage is required when the current waveform rises, and the equipment cost of the power supply may increase.

As hydrophilic particles, Al ₂ O ₃ and Ti are used.
It is preferable to use O ₂ , SiO ₂ and ZrO ₂ alone or in combination of two or more kinds. The electrolytic solution is obtained, for example, by suspending the hydrophilic particles in water or the like so that the content of the hydrophilic particles is 0.01 to 20% of the whole. In order to positively or negatively charge the electrolytic solution, for example, sulfuric acid may be added to adjust the pH. For the electrolytic treatment, for example, direct current is used, an aluminum plate is used as a cathode, and the above electrolytic solution is used.
The condition is 00 seconds. According to this method, it is possible to easily close the mouth of the micropore existing in the anodized film while leaving a void inside the micropore.

As another method of sealing treatment, carboxymethyl cellulose; dextrin; gum arabic; phosphonic acids having an amino group such as 2-aminoethylphosphonic acid; phenylphosphonic acid which may have a substituent and naphthylphosphone Acids, organic phosphonic acids such as alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid, ethylenediphosphonic acid; phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid and the like, which may have a substituent Phosphoric acid ester; Organic phosphinic acid such as optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid; Amino acids such as glycine and β-alanine;
There is also a method of providing a layer of a compound selected from a hydrochloride of an amine having a hydroxy group such as a hydrochloride of triethanolamine.

Further, the sealing treatment may be carried out by applying a silane coupling agent having an unsaturated group. Examples of the silane coupling agent include N-3- (acryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, (3-acryloxypropyl) dimethylmethoxysilane, (3-acryloxypropyl) methyldimethoxy. Silane, (3-acryloxypropyl) trimethoxysilane, 3- (N-allylamino) propyltrimethoxysilane, allyldimethoxysilane, allyltriethoxysilane, allyltrimethoxysilane, 3-
Butenyltriethoxysilane, 2- (chloromethyl) allyltrimethoxysilane, methacrylamidopropyltriethoxysilane, N- (3-methacryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, (methacryloxymethyl) Dimethylethoxysilane, Methacryloxymethyltriethoxysilane, Methacryloxymethyltrimethoxysilane, Methacryloxypropyldimethylethoxysilane, Methacryloxypropyldimethylmethoxysilane, Methacryloxypropylmethyldiethoxysilane, Methacryloxypropylmethyldimethoxysilane, Methacryloxypropyl Methyltriethoxysilane, methacryloxypropylmethyltrimethoxysilane, methacryloxypropyltris (methoxyethoxy) si Emissions, methoxy dimethylvinylsilane, 1-methoxy-3- (trimethylsiloxy) butadiene, styrylethyltrimethoxysilane, 3- (N-
Styrylmethyl-2-aminoethylamino) -propyltrimethoxysilane hydrochloride, vinyldimethylethoxysilane, vinyldiphenylethoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, O
-(Vinyloxyethyl) -N- (triethoxysilylpropyl) urethane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri-t-butoxysilane, vinyltriisopropoxysilane, vinyltriphenoxysilane, vinyltris (2-methoxyethoxy) ) Silane and diallylaminopropylmethoxysilane. Of these, a silane coupling agent having a methacryloyl group or an acryloyl group, which has a fast unsaturated group reactivity, is preferable.

Other than that, the sol-gel coating treatment described in JP-A-5-50779,
-246171, coating treatment of phosphonic acids, JP-A-6-234284, JP-A-6-191173 and JP-A-6-23056.
Japanese Patent Laid-Open No. 6-262872, Japanese Patent Laid-Open No. 6-262872, Japanese Patent Laid-Open No. 6-262872.
The coating treatment described in JP-A-297875, the method of anodizing treatment described in JP-A-10-109480, Japanese Patent Application No. 10-252078 (Japanese Patent Application Laid-Open No. 2000-81704) and Japanese Patent Application Flat 1
0-253411 (JP-A-2000-89466)
Dip treatment method, etc.
Either method may be used.

<Hydrophilic surface treatment> In the present invention, the lithographic printing plate substrate of the present invention obtained by providing the hydrophilic film as described above is further treated with an aqueous solution containing one or more hydrophilic compounds. It is preferable to perform hydrophilic surface treatment by dipping.

A method of treating with an alkali metal silicate (alkali metal silicate) described in US Pat. Nos. 2,714,066 and 3,181,461, JP-B-36-22063. Japanese Patent Application Laid-Open No. 9-24 / 1994, a method of treating with potassium fluorozirconate described in US Pat. No. 4,153,461, and a method of treating with polyvinylphosphonic acid described in US Pat. No. 4,153,461.
No. 4227, a method of treating with an aqueous solution containing a phosphate and an inorganic fluorine compound;
The method of treating with an aqueous solution containing titanium and fluorine described in JP-A-252078 and JP-A-10-263411 is mentioned. Among them, the method of treating with an alkali metal silicate and the method of treating with polyvinylphosphonic acid are preferable.

Examples of the alkali metal silicate used in the method of treating with an alkali metal silicate include sodium silicate, potassium silicate, and lithium silicate.

The method of treatment with an alkali metal silicate is as follows:
For example, the alkali metal silicate concentration is 0.01 to 30.
%, Preferably 0.01 to 10%, more preferably 0.
The aluminum substrate provided with the above-mentioned particle layer is added to an aqueous solution of an alkali metal silicate having a pH of 05 to 3% at 25 ° C of 10 to 13 at 4 to 80 ° C, preferably 0.5 to 1
A method of immersing for 20 seconds, more preferably for 2 to 30 seconds may be mentioned. Alkali metal silicate concentration, pH,
Processing conditions such as temperature and processing time can be appropriately selected. If the pH of the aqueous alkali metal silicate solution is lower than 10, the solution tends to gel, and if the pH is higher than 13, the particle layer and the anodic oxide film may be dissolved.

In the above hydrophilic treatment, if necessary,
In order to adjust the pH of the alkali metal silicate aqueous solution to a high level, a hydroxide can be added. Examples of the hydroxide include sodium hydroxide, potassium hydroxide and lithium hydroxide.

If necessary, an alkaline earth metal salt and / or Group 4 (IVA
A group) metal salt may be added. Examples of alkaline earth metal salts include alkaline earth metal nitrates (eg, calcium nitrate, strontium nitrate, magnesium nitrate, barium nitrate), sulfates, hydrochlorides, phosphates, acetates, oxalates, and borates. Water-soluble salts such as acid salts can be mentioned. Examples of the Group 4 (Group IVA) metal salt include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, potassium potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride oxide, zirconium dioxide, zirconium oxychloride. , Zirconium tetrachloride. The alkaline earth metal salt and the Group 4 (Group IVA) metal salt may be used alone or in combination of two or more kinds. The amount of these metal salts used is preferably 0.01 to
It is 10%, and more preferably 0.05 to 5.0%.

The aqueous solution used in the method for treating with polyvinylphosphonic acid has, for example, a polyvinylphosphonic acid concentration of 0.01 to 10%, preferably 0.1 to 5%, more preferably 0.2 to 2.5%. The temperature is 10 ° C to 70 ° C, preferably 30 ° C to 60 ° C. The hydrophilic treatment can be carried out by immersing the aluminum substrate provided with the particle layer in the aqueous solution, for example, for 0.5 seconds to 10 minutes, preferably for 1 second to 30 seconds.

Treatment with an aqueous solution of potassium zirconium fluoride is preferably carried out by treating the substrate with an aqueous solution of potassium zirconium fluoride having a concentration of 0.1 to 10%, more preferably 0.5 to 2%, preferably at 30 to 80 ° C. , Preferably 6
It is performed by immersing for 0 to 180 seconds.

In the phosphate / inorganic fluorine compound treatment, the phosphate compound concentration is preferably 5 to 20%, the inorganic fluorine compound concentration is 0.01 to 1%, and the pH is preferably 3.
An aluminum substrate, preferably 20
~ 100 ° C, more preferably 40 to 80 ° C, preferably 2 to 300 seconds, more preferably 5 to 30 seconds.

Examples of the phosphate used in the present invention include phosphates of metals such as alkali metals and alkaline earth metals. Specifically, for example, zinc phosphate,
Aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, potassium dihydrogenphosphate, dipotassium hydrogenphosphate, calcium phosphate, phosphorus Sodium ammonium hydrogen hydride,
Magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, disodium hydrogen phosphate, lead phosphate, diammonium phosphate, dihydrogen phosphate Calcium, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate;
Examples include sodium phosphite, sodium tripolyphosphate, and sodium pyrophosphate. Among them, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate and dipotassium hydrogen phosphate are preferable.

Suitable examples of the inorganic fluorine compound used in the present invention include metal fluorides. Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium hexafluorozirconium, potassium hexafluorozirconium, sodium hexafluorotitanate, potassium hexafluorotitanate, hexafluorozirconium oxyhydroxide , Hexafluorotitanium hydrogen acid, hexafluorozirconium ammonium, hexafluorotitanate ammonium, hexafluorosilicic acid, nickel fluoride, iron fluoride, fluorophosphoric acid, and ammonium fluorophosphate.

The aqueous solution used for the phosphate / inorganic fluorine compound treatment may contain one kind or two or more kinds of phosphate and inorganic fluorine compound, respectively.

In the present invention, in addition to the above aqueous solution,
Suitable compounds include compounds having a sulfonic acid group and sugar compounds.

The compounds having a sulfonic acid group include aromatic sulfonic acids, their formaldehyde condensates, their derivatives, and their salts.

Examples of the aromatic sulfonic acid include phenol sulfonic acid, catechol sulfonic acid, resorcinol sulfonic acid, benzene sulfonic acid, toluene sulfonic acid, lignin sulfonic acid, naphthalene sulfonic acid, acenaphthene-5-sulfonic acid and phenanthrene-2. -Sulfonic acid, benzaldehyde-2 (or 3) -sulfonic acid, benzaldehyde-2,4 (or 3,5) -disulfonic acid, oxybenzyl sulfonic acids, sulfobenzoic acid, sulfanilic acid, naphthoic acid, and taurine. Of these, benzenesulfonic acid, naphthalenesulfonic acid, and ligninsulfonic acid are preferable. Further, formaldehyde condensates of benzenesulfonic acid, naphthalenesulfonic acid and ligninsulfonic acid are also preferable. Furthermore, they may be used as sulfonates. Examples thereof include sodium salt, potassium salt, lithium salt, calcium salt and magnesium salt. Of these, sodium salts and potassium salts are preferable.

The pH of the aqueous solution containing the compound having a sulfonic acid group is preferably 4 to 6.5, and sulfuric acid,
The pH range can be adjusted using sodium hydroxide, ammonia or the like.

The saccharide compounds include monosaccharides and sugar alcohols thereof, oligosaccharides, polysaccharides and glycosides.

Examples of monosaccharides and sugar alcohols thereof include trioses such as glycerol and sugar alcohols thereof; tetrose such as threose and erythritol and sugar alcohols thereof; pentoses such as arabinose and arabitol and sugar alcohols thereof; glucose. , Sorbitol and other hexoses and their sugar alcohols; D
-Glycero-D-galactoheptose, D-glycero-
Heptose such as D-galactoheptitol and its sugar alcohols; Octose such as D-erythro-D-galactooctitol and its sugar alcohols; Nonose such as D-erythro-L-gluco-nonulose and its sugar alcohols Is mentioned.

Examples of oligosaccharides include disaccharides such as saccharose, trehalose and lactose; and trisaccharides such as raffinose.

Examples of the polysaccharides include amylose, arabinan, cyclodextrin and cellulose alginate.

In the present invention, the "glycoside" refers to a compound in which a sugar moiety and a non-sugar moiety are bound via an ether bond or the like. Glycosides can be classified by the non-sugar moiety. For example, alkyl glycosides, phenol glycosides, coumarin glycosides, oxycoumarin glycosides, flavonoid glycosides, anthraquinone glycosides, triterpene glycosides, steroid glycosides, mustard oil glycosides Can be mentioned.

Examples of the sugar moiety include the above-mentioned monosaccharides and sugar alcohols thereof; oligosaccharides and polysaccharides. Among them, monosaccharides and oligosaccharides are preferable, and monosaccharides and disaccharides are more preferable.

Examples of preferred glycosides include the following formula (I)
The compound represented by

[0196]

[Chemical 5]

In the above formula (I), R represents 1 to 2 carbon atoms.
Represents a straight chain or branched group of 0, an alkyl group, an alkenyl group or an alkynyl group.

Examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, Dodecyl group,
Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group may be mentioned, and these may be linear or branched, and cyclic alkyl It may be a group.

Examples of the alkenyl group having 1 to 20 carbon atoms include an allyl group and a 2-butenyl group, which may be linear or branched and may be cyclic. It may be an alkenyl group.

Examples of the alkynyl group having 1 to 20 carbon atoms include a 1-pentynyl group, which may be linear or branched, and a cyclic alkynyl group. It may be.

Specific compounds represented by the above formula (I) include, for example, methyl glucoside, ethyl glucoside, propyl glucoside, isopropyl glucoside, butyl glucoside, isobutyl glucoside, n-hexyl glucoside, octyl glucoside, capryl glucoside, Examples include decyl glucoside, 2-ethylhexyl glucoside, 2-pentylnonyl glucoside, 2-hexyl decyl glucoside, lauryl glucoside, myristyl glucoside, stearyl glucoside, cyclohexyl glucoside, and 2-butynyl glucoside. These compounds are glucosides, which are a type of glycoside, in which the hemiacetal hydroxyl group of glucose is bound to another compound in an ether form, and obtained by, for example, a known method of reacting glucose with alcohol be able to. Some of these alkyl glucosides are found in German He
Trade name GLUCOPO by Nkel
N), which is commercially available and can be used in the present invention.

Other examples of preferred glycosides include saponins, rutin trihydrate, hesperidin methylchalcone, hesperidin, naridin hydrate, phenol-β-D-glucopyranoside, salicin, 3 ',
5,7-methoxy-7-rutinoside may be mentioned.

The pH of the aqueous solution containing the saccharide compound is 8
It is preferably -11 and can be adjusted to the above pH range using potassium hydroxide, sulfuric acid, carbonic acid, sodium carbonate, phosphoric acid, sodium phosphate and the like.

An aqueous solution of a compound having a sulfonic acid group is
The concentration is preferably 0.02 to 0.2%. The immersion temperature is preferably 60 to 100 ° C. Immersion time is 1
It is preferably ˜300 seconds, more preferably 10 to 100 seconds.

Further, the aqueous solution of the saccharide compound has a concentration of 0.
It is preferably 5 to 10%. Immersion temperature is 40-70
It is preferably in ° C. The immersion time is preferably 2 to 300 seconds, more preferably 5 to 30 seconds.

After being immersed in an aqueous solution containing these hydrophilic compounds, the substrate is washed with water or the like and dried.

By the hydrophilic surface treatment described above, the sensitivity (improvement in printing durability in the case of a negative type photosensitive layer) improved by the pore widening treatment after the anodizing treatment and the print stain such as deterioration of ink repellency which occurs in exchange. The problem goes away.
That is, due to the increase in the pore diameter, it becomes difficult to remove the ink during printing, especially when the printing machine is stopped and the lithographic printing plate is left on the printing machine and then restarted (deterioration of ink-repelling property). However, when the hydrophilic surface treatment is applied, the above problems are alleviated.

<Undercoat Layer> In the present invention, if necessary, before providing an image forming layer writable by infrared laser exposure on the thus obtained lithographic printing plate substrate of the present invention. For example, a water-soluble metal salt such as zinc borate or an inorganic undercoat layer such as a phosphate described in JP-A-62-19494, or the following organic undercoat layer may be provided.

Examples of the organic undercoat layer include those disclosed in Japanese Patent Laid-Open No.
No. 0-149491, a compound having at least one amino group and at least one group selected from the group consisting of a carboxyl group and a salt group thereof, and a sulfo group and a salt group thereof. A layer comprising a compound selected from the group consisting of compounds having at least one amino group and at least one hydroxy group and salts thereof, which are described in JP-A-60-232998.
Examples thereof include a layer formed of a polymer compound having in the molecule at least one kind of monomer unit having a sulfo group described in JP-A-59-101651.

Specific organic compounds used in the organic undercoat layer include, for example, amino acids such as glycine, p-hydroxyphenylglycine, dihydroxyethylglycine, β-alanine, lysine and aspartic acid, and their sodium salts and potassium. Salts, salts such as ammonium salts, aliphatic aminosulfonic acids such as sulfamic acid and cyclohexylsulfamic acid and salts thereof such as sodium salts, potassium salts and ammonium salts, monoethanolamine,
Amine having a hydroxyl group such as diethanolamine, triethanolamine, and tripropanolamine, and salts thereof such as hydrochloride, oxalate, and phosphate, p-styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, Allyl sulfonic acid, methallyl sulfonic acid, ethylene sulfonic acid or a polymer or copolymer containing a salt thereof as a monomer unit, further,
Carboxymethyl cellulose; Dextrin; Gum arabic; Polyacrylic acid; Phosphonic acids having an amino group such as 2-aminoethylphosphonic acid; Phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid which may have a substituent Acids, methylenediphosphonic acid, organic phosphonic acids such as ethylenediphosphonic acid;
Organic phosphoric acid such as phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid, glycerophosphoric acid which may have a substituent; phenylphosphinic acid which may have a substituent,
Examples thereof include organic phosphinic acids such as naphthylphosphinic acid, alkylphosphinic acid, and glycerophosphinic acid. These may be used alone or in combination of two or more.

The organic undercoat layer is provided by applying a solution prepared by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, methyl ethyl ketone or the like, or a mixed solvent thereof onto an aluminum plate and drying it. The concentration of the solution in which the above organic compound is dissolved is 0.005
It is preferably 10%. The coating method is not particularly limited, and any method such as bar coater coating, spin coating, spray coating and curtain coating can be used.

The coating amount of the organic undercoat layer after drying is 2 to 20.
It is preferably 0 mg / m ² , and 5 to 100 mg / m ^2.
Is more preferable. Within the above range, printing durability will be better.

<Backcoat Layer> When the aluminum substrate obtained as described above is used as a lithographic printing plate precursor, the back surface (image forming layer is provided so that the image forming layer is not scratched even when stacked). A coating layer made of an organic polymer compound (hereinafter, also referred to as “back coat layer”) may be provided on the surface not provided) as necessary.

The main component of the back coat layer is a saturated copolyester resin having a glass transition point of 20 ° C. or higher,
It is preferable to use at least one resin selected from the group consisting of a phenoxy resin, a polyvinyl acetal resin and a vinylidene chloride copolymer resin.

The saturated copolymerized polyester resin comprises a dicarboxylic acid unit and a diol unit. Examples of the dicarboxylic acid unit include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, tetrabromophthalic acid and tetrachlorophthalic acid; adipic acid, azelaic acid, succinic acid, oxalic acid, suberic acid and sebacic acid. And saturated aliphatic dicarboxylic acids such as malonic acid and 1,4-cyclohexanedicarboxylic acid.

The back coat layer further comprises a dye or pigment for coloring, a silane coupling agent for improving adhesion to the substrate, a diazo resin containing a diazonium salt, an organic phosphonic acid, an organic phosphoric acid, a cationic A polymer, a wax usually used as a slip agent, a higher fatty acid, a higher fatty acid amide, a silicone compound composed of dimethylsiloxane, a modified dimethylsiloxane, a polyethylene powder and the like can be appropriately contained.

The thickness of the back coat layer may basically be 0.01 to 8 μm as long as it does not scratch the image forming layer described later even if there is no interleaving paper. When the thickness is less than 0.01 μm, it is difficult to prevent scratches on the image forming layer when the planographic printing plate precursors are stacked and handled. When the thickness exceeds 8 μm, during printing,
The back coat layer may swell due to chemicals used around the lithographic printing plate, the thickness may change, and the printing pressure may change to deteriorate the printing characteristics.

Various methods can be used for providing the backcoat layer on the back surface of the aluminum substrate. For example, a method in which the components for the back coat layer are dissolved in a suitable solvent and applied as a solution, or an emulsified dispersion is applied and then dried; a film previously formed into an adhesive or a substrate with heat. And a method of forming a molten coating with a melt extruder and then laminating it to a substrate. The most preferable method for ensuring a suitable thickness is a method in which the components for the backcoat layer are dissolved in a suitable solvent to form a solution, which is then applied and dried. In this method, an organic solvent as described in JP-A No. 62-251739 can be used alone or in combination as a solvent.

In the production of the lithographic printing plate precursor, either the back coat layer on the back side or the image forming layer on the front side may be provided on the substrate first, or both may be provided at the same time.

[Plate making and printing] The planographic printing plate precursor of the invention is image-formed by heat. Specifically, direct image-like recording with a thermal recording head, scanning exposure with an infrared laser, high-illuminance flash exposure with a xenon discharge lamp, infrared lamp exposure, or the like is used.
Exposure with a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits 0 nm infrared is suitable.

The lithographic printing plate precursor of the present invention, which has been imagewise exposed, can be mounted on a printing machine without further treatment and can be printed by a usual procedure using ink and fountain solution. In addition, these planographic printing plate precursors are disclosed in Japanese Patent No. 29383.
As described in No. 98, after mounting on the plate cylinder of a printing machine, it is exposed by a laser mounted on the printing machine, and then fountain solution and / or ink is added to perform on-press development. It is possible. Further, these lithographic printing plate precursors can also be used for printing after development using water or a suitable aqueous solution as a developing solution.

[0222]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Production Example of Aluminum Substrate Using a JIS 1050 aluminum plate having a thickness of 0.24 mm, pretreatment, surface roughening treatment, hydrophilic film formation treatment, and if necessary posttreatment were carried out in this order, and the planographic printing plate of the embodiment was prepared. An aluminum substrate used as a printing plate precursor was produced. Up to the roughening treatment, any one of the following A to I was performed, and the hydrophilic film forming treatment and the post-treatment were performed by the method described in the production example of each substrate.

<Roughening Treatments A, B and C> An aluminum plate was immersed in a 1% sodium hydroxide aqueous solution kept at 50 ° C. and subjected to a dissolution treatment so that the amount of dissolution would be 2 g / m ² . . After washing with water, it was immersed for 10 seconds in an aqueous solution having the same composition as the electrolytic solution used in the subsequent electrochemical graining treatment for neutralization treatment, and then washed with water.

Next, this aluminum substrate material was subjected to electrochemical roughening treatment divided into a plurality of times with a current density of 50 A / dm ² and a sine wave alternating current, with a rest period interposed. Table 1
The electrolytic solution composition, the amount of electricity processed per time, the number of times of electrolytic treatment, and the dwell time are shown. After the electrochemical graining treatment,
It is immersed in a 1% sodium hydroxide aqueous solution kept at 50 ° C., alkali-dissolved so that the amount of dissolution becomes 2 g / m ² , washed with water, and then 10 times in a 10% sulfuric acid aqueous solution kept at 25 ° C. It was immersed for 2 seconds for neutralization, and then washed with water.

[0226]

[Table 1]

<Roughening treatment D> The aluminum plate is heated to 50 ° C.
Dipped in 10% aqueous sodium hydroxide solution for 20 seconds,
After degreasing and etching, rinse with running water, then 25
% Aqueous solution of sulfuric acid for 20 seconds for neutralization and washing with water. Then, using a 1% hydrochloric acid aqueous solution (containing 0.5% of aluminum ion), a trapezoidal rectangular wave having a frequency (60) of 2 msec and a duty ratio of 1: 1 while the current value reaches a peak from 0. With a carbon electrode as a counter electrode, the average current density at the time of aluminum anode was 27 A / dm ² (the ratio of the current density at the time of anode and cathode of aluminum was 1: 0.9.
5), average electricity quantity at aluminum anode 350C / dm ²
The electrolytic surface-roughening treatment was performed at 20 ° C. Then
Sodium hydroxide 26%, Aluminum ion 6.5%
Using an aqueous solution, etching treatment by spraying was performed at a liquid temperature of 45 ° C. so that the total etching amount including smut was 0.7 g / m ² . Subsequently, desmutting treatment was carried out by spraying treatment at 60 ° C. for 10 seconds with a 25% nitric acid aqueous solution (containing 0.3% of aluminum ions).

<Roughening Treatment E> After roughening the surface of the aluminum plate with a nylon brush having a bristle diameter of 0.72 mm and a bristle length of 80 mm and an aqueous suspension of pumicetone having an average particle diameter of about 15 to 35 μm, Washed well with water. Next, it was immersed in a 10% aqueous sodium hydroxide solution at 70 ° C. for 30 seconds for etching, washed with running water, neutralized with a 20% aqueous nitric acid solution, and washed with water. The aluminum plate thus mechanically roughened was further subjected to the following electrochemical roughening.

The hydrochloric acid concentration was 7.5 g / l, and the solution temperature was 3 in an aqueous hydrochloric acid solution prepared by adding aluminum chloride to hydrochloric acid so that the aluminum ion concentration became 5 g / l.
AC electrolysis was performed by applying an alternating current to the aluminum plate subjected to the mechanical roughening at 5 ° C. using the radial cell shown in FIG. As the alternating current, commercial alternating current with a frequency of 60 Hz can be used to convert current and current by using an induction voltage regulator and a transformer.
A sine wave generated by adjusting the voltage was used.
The total amount of electricity when the aluminum plate is the anode is 50 C / dm
² and Qc / Qa in one cycle of the alternating current is 0.
It was 95.

Regarding the concentrations of hydrochloric acid and aluminum ions in the above hydrochloric acid aqueous solution, the relationship between the temperature, the conductivity, and the ultrasonic wave propagation velocity, and the concentrations of hydrochloric acid and aluminum ions was obtained. Concentrated hydrochloric acid having a concentration of 35% and water were added to the inside of the electrolytic cell main body from the circulation tank so that the sound wave propagation velocity reached a predetermined value, and the excess hydrochloric acid aqueous solution was overflowed to keep it constant. Next, an alkaline solution containing 5% and 0.5% of sodium hydroxide and aluminum ion, respectively, and having a liquid temperature of 45 ° C. was used as a treatment liquid, and the dissolution amount of the roughened surface of the aluminum plate was 0. It was 1 g / m ^2, and the surface such that the dissolution amount 0.05 g / m ² of the surface on the opposite side was subjected to etching treatment.

[0231] Sulfuric acid and aluminum ions were added to both sides of the etched aluminum plate by 300 times, respectively.
Desmutting treatment was performed by spraying a sulfuric acid aqueous solution containing g / l and 5 g / l at a liquid temperature of 50 ° C.

<Roughening treatment F> After the roughening treatment A, a 1% nitric acid aqueous solution (containing 0.5% of aluminum ion) was further used to measure the time (TP ) Is a trapezoidal rectangular wave having a frequency of 60 msec for 2 msec and a duty ratio of 1: 1 and an average current density of 27 A / dm ² at the time of an aluminum anode with a carbon electrode as a counter electrode (a ratio of the current density at the time of an anode of aluminum to that of a cathode 1: 0.9
5), average electricity quantity at aluminum anode 350C / dm ²
So that the electrolytic graining treatment was performed at 50 ° C. using the radial cell shown in FIG. Then, using a 26% sodium hydroxide and 6.5% aluminum ion aqueous solution, the total etching amount including smut is 0.2 g / 45 ° C. at a liquid temperature of 45 ° C.
It was etched by spraying such that m ^2. Subsequently, desmutting treatment was carried out by spraying treatment at 60 ° C. for 10 seconds with a 25% nitric acid aqueous solution (containing 0.3% of aluminum ions).

Production of Substrates 1 to 6 Each of the roughened substrates A to F was subjected to a sulfuric acid concentration of 170 g / l (containing 0.5% of aluminum ion), a liquid temperature of 40 ° C., and a current density using an anodic oxidation apparatus. 30 A / dm ²
Was anodized for 20 seconds and washed with water. Next, it was immersed in an aqueous solution of sodium hydroxide having a pH of 13 at a liquid temperature of 30 ° C. for 70 seconds and then washed with water. Next, colloidal silica (Snowtex ST-N manufactured by Nissan Chemical Industries, Ltd., particle size of about 2)
(0 nm) was immersed in a 1% aqueous solution at 70 ° C. for 14 seconds and then washed with water. Next, add 7% to 2.5% sodium silicate No. 3.
Substrates 1 to 6 were manufactured by immersing at 0 ° C. for 14 seconds and then washing with water.

Production of Substrate 7 An aluminum plate subjected to surface roughening treatment E was anodized at a current density of 12 A / dm ² for 2 minutes in a 50 g / l solution of oxalic acid at 30 ° C., and washed with water to obtain 4 g. / M ²
The anodic oxide film of was produced. Next, pH 13, liquid temperature 50 ℃
It was immersed in the aqueous sodium hydroxide solution for 2 minutes and then washed with water. Next, add 2.5% sodium silicate 1 at 70 ° C.
After soaking for 4 seconds, the substrate 7 was manufactured by washing with water.

Manufacture of Substrate 8 An aluminum plate subjected to the surface roughening treatment E is treated with sulfuric acid concentration 170
g / l (containing 0.5% aluminum ion), liquid temperature 3
It was anodized at 0 ° C. and a current density of 5 A / dm ^{2 for} 70 seconds, and washed with water. Next, it was immersed in a sodium hydroxide aqueous solution having a pH of 13 and a liquid temperature of 30 ° C. for 30 seconds, and then washed with water.
Next, the substrate 8 was manufactured by performing sodium silicate treatment and washing with water in the same manner as in Manufacturing Example 7.

Production of Substrates 9 to 13 Except that the anodizing time of Production Example 5 using the substrate subjected to the surface roughening treatment E was changed to 12 seconds, 16 seconds, 24 seconds, 44 seconds and 90 seconds, In the same manner as in Production Example 5, each of the substrates 9
~ 13 were produced.

Production of Substrate 14 Substrate 14 was produced in the same manner as in Example 5 for producing substrate 5, except that the immersion treatment of the colloidal silica aqueous solution was not carried out.

Production of Substrate 15 Anodizing was performed on the substrate subjected to the roughening treatment E using an electrolytic solution having a sulfuric acid concentration of 100 g / l and an aluminum ion concentration of 5 g / l at a liquid temperature of 51 ° C. and a current density of 30 A / dm ^2. It was treated and washed with water to form a 2 g / m ² anodized film. Next, sulfuric acid concentration 170g / l, aluminum ion concentration 5
Liquid temperature 40 ° C, current density 30A using g / l electrolyte
/ Dm ² for anodic oxidation and the total oxide film amount is 4.0 g /
It was adjusted to m ² and washed with water to form an anodized film. Next, the substrate 15 was manufactured by immersing in a 2.5% aqueous solution of No. 3 sodium silicate at a liquid temperature of 70 ° C. for 14 seconds and then washing with water.

Production of Substrate 16 Anodizing was performed on the substrate subjected to the surface roughening treatment E using an electrolytic solution having a sulfuric acid concentration of 170 g / l and an aluminum ion concentration of 5 g / l at a liquid temperature of 43 ° C. and a current density of 30 A / dm ^2. It was treated and washed with water to form a 2 g / m ² anodized film. Next, phosphoric acid 120g / l, aluminum ion concentration 5g
/ L electrolyte solution, liquid temperature 40 ℃, current density 18A /
It was anodized at dm ² and washed with water. Next, the substrate 16 was manufactured by immersing it in a 2.5% aqueous solution of No. 3 sodium silicate at a liquid temperature of 70 ° C. for 14 seconds and then rinsing with water.

Table 2 shows the roughened shape of the aluminum substrate and the physical property values of the hydrophilic film obtained in the above Production Example. The measuring method of each physical property value is as follows. The density was measured by the method described above.

<Measurement Method of Large Waviness Average Opening Diameter, Small Pit Average Opening Diameter, and Ratio of Small Pit Average Depth to Small Pit Average Opening Diameter> For all values, SEM photographs of the surface of the aluminum substrate were taken. Measured. For the average opening diameter d ₂ (μm) of the large swell, 1000 times the SEM
Using the photograph, the major axis and the minor axis of each undulation whose contour can be clearly discriminated are measured, and the average is taken as the undulation opening diameter, and the sum of the large undulation opening diameters measured in the SEM photograph is measured. It was calculated by dividing the number of large swells made by 50.
As the SEM, T-20 manufactured by JEOL Ltd. was used.

For the measurement of the average opening diameter d ₁ (μm) of the small pits, a SEM photograph with a magnification of 30,000 was used, and the same method as for the opening diameter with a large undulation was used. The SEM used in this case was Hitachi S-900.

The ratio h / d ₁ of the average depth h (μm) of the small pits and the average opening diameter d ₁ (μm) of the small pits is 3
It was measured using a SEM photograph of 0000 times and measured 50
The average value of several points was used.

<Method for measuring thermal conductivity in the film thickness direction of hydrophilic film>
First, in addition to the aluminum substrates 1 to 16 of the present invention and the substrates 1 to 5 for comparative examples, two types of aluminum substrates having different hydrophilic film thicknesses from these substrates were prepared. Aluminum substrates having different film thicknesses were produced by the same method as the aluminum substrate shown in the production example except that the anodic oxidation time was set to 0.5 times and 2 times, respectively.

Next, three types of aluminum substrates differing only in film thickness were subjected to measurement by the apparatus shown in FIG. 2, and the thermal conductivity in the film thickness direction of the hydrophilic film was calculated by the above mathematical formula (1). The measurement was performed at five different points on the sample, and the average value was used.

Here, the film thickness of the hydrophilic film was obtained by observing the cross section of the hydrophilic film using SEM T-20 manufactured by JEOL Ltd., measuring the film thickness at 50 locations, and using the average value thereof.

<Method of Measuring Pore Diameter of Anodized Film Micropores> The pore diameter of the anodized film micropores was measured with respect to the surface pore diameter and the pore diameter at a depth of 0.4 μm from the surface layer. For the surface pore size, bend the anodized film surface, and for the 0.4 μm pore size from the surface layer, bend the anodized aluminum substrate, and then bend the side surface of the cracked part (usually a fracture surface). ) Was observed using an ultra high resolution SEM (Hitachi S-900).
The observation was performed at a relatively low accelerating voltage of 12 V and at a magnification of 150,000 times without performing a vapor deposition process for imparting conductivity. For both pore diameters, the average value of the measured values obtained by randomly extracting 50 pores was used. The standard deviation error was less than ± 10% in both cases.

<Porosity Measuring Method> The porosity of the anodized film was determined by the following formula. Porosity (%) = {1- (oxide film density / 3.98)} x
100 Here, 3.98 is the density (g / cm ³ ) of aluminum oxide according to the Chemical Handbook.

[0249]

[Table 2]

Production Example of Fine Particles <Production of Polymer Fine Particles> A 1000 ml four-necked flask was equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen introducing tube, and a reflux condenser, and nitrogen gas was introduced to deoxidize it. While adding 350 cc of distilled water, the mixture was heated until the internal temperature reached 80 ° C.
As a dispersant, 3.0 g of sodium dodecyl sulfate was added to 1.5
g, and ammonium persulfide as an initiator 0.4
5 g, then glycidyl methacrylate 45.
A mixture of 0 g and 45.0 g of styrene was added dropwise from the dropping funnel over about 1 hour. After the dropping was completed, the reaction was continued for 5 hours, and then unreacted monomers were removed by steam distillation.
Then, the mixture was cooled and adjusted to pH 6 with aqueous ammonia, and finally pure water was added so that the nonvolatile content became 15% to obtain an aqueous dispersion of fine polymer particles. The particle size distribution of the high polymer particles had a maximum value at a particle size of 60 nm.

Here, the particle size distribution is determined by taking an electron micrograph of the polymer particles, measuring 5000 particle sizes of the particles in total on the photo, and observing from the maximum value of the obtained particle size measurement values to 0.
The space was divided into 50 on a logarithmic scale, and the appearance frequency of each particle size was plotted and obtained. Regarding non-spherical particles, the particle size value of spherical particles having the same particle area as the particle area on the photograph was defined as the particle size.

<Production of Microcapsules> 30 g of an adduct of trimethylolpropane and xylylenediisocyanate as an oil phase component (D-110N manufactured by Takeda Pharmaceutical Co., Ltd.),
Epicoat 1001 (produced by Yuka Shell Epoxy Co., Ltd.) 3
0 g, photothermal conversion agent (IR-26 described herein) 8 g,
Crystal Violet Lactone 0.5g, Anionic Surfactant Pionin A41C (Takemoto Yushi) 0.5g
Was dissolved in 90 g of ethyl acetate. PV as the water phase component
180 g of a 4% aqueous solution of A205 (manufactured by Kuraray) was prepared. Oil phase component and water phase component 1 using a homogenizer
It was emulsified at 0000 rpm. Then, 120 g of water was added, and the mixture was stirred at room temperature for 30 minutes and further at 40 ° C. for 3 hours. The thus obtained microcapsule solution had a solid content concentration of 18% and an average particle size of 200 nm.

Examples 1 to 4 and Comparative Examples 1 to 4 Bar coating was performed on the aluminum substrate of No. 1 using the coating solutions 1 and 2 of the following image forming layers as shown in Table 3 and then dried in an oven at 70 ° C. for 60 seconds to give a dry coating amount of 0.6 g / m 2. ^Two image forming layers were prepared.

[0254] (Image forming layer coating liquid 1)     Polymer fine particles (as solid content) 5.0 g     Light-to-heat conversion agent (IR-11 described in this specification) 1.0 g     Pentaerythritol tetraacrylate 1.0g     Methanol 16.0g     Water 24.0g

[0255] (Image forming layer coating liquid 2)     Polymer fine particles (as solid content) 5.0 g     Light-to-heat conversion agent (IR-11 described in this specification) 1.0 g     Pentaerythritol tetraacrylate 0.2g     Polyacrylic acid (weight average molecular weight 25,000) 0.8g     Methanol 16.0g     Water 24.0g

Further, the following overcoat layer coating solutions 1 to 4 were bar-coated in the combinations shown in Table 3 and then dried in an oven at 60 ° C. for 120 seconds, and the dry coating amount of the overcoat layer was 0. It was 0.3 g / m ² .

[0257] (Overcoat layer coating liquid 1)     Carboxymethyl cellulose (weight average molecular weight 20,000) 5.0 g     Water 50.0g

[0258] (Overcoat layer coating liquid 2)     Polymer fine particles (as solid content) 4.0 g     Polyacrylic acid (weight average molecular weight 25,000) 1.0 g     Photothermal conversion agent (IR-11 described in the present specification) 0.1 g     Water 50.0g

[0259] (Overcoat layer coating liquid 3)     Microcapsules (as solid content) 4.0 g     Polyacrylic acid (weight average molecular weight 25,000) 1.0 g     Photothermal conversion agent (IR-11 described in the present specification) 0.1 g     Water 50.0g

[0260] (Overcoat layer coating liquid 4)     Microcapsules (as solid content) 4.0 g     Polyacrylic acid (weight average molecular weight 25,000) 1.0 g     Light-to-heat conversion agent (IR-11 described in the specification) 1.5 g     Water 50.0g

The lithographic printing plate precursor thus obtained was output by a Creo Trendsetter 3244VFS equipped with a water-cooled 40W infrared semiconductor laser with an output of 9W.
External drum rotation speed 105 rpm, plate energy 200
After exposure under the conditions of mJ / cm ² and resolution of 2400 dpi, the printing machine SO manufactured by Heidelberg was used without processing.
After attaching to the RM cylinder and supplying dampening water,
Printing was performed by supplying ink. Each of the printing plate precursors had good on-press developability. Table 3 shows the presence or absence of ablation and the number of printable sheets by observation of the plate surface after exposure.

[0262]

[Table 3]

From the above results, the printing plate precursor using the lipophilic image forming layer containing no hydrophilic binder resin has higher durability than the printing plate precursor using the image forming layer containing the hydrophilic binder resin. It can be seen that higher printing durability can be obtained by using an overcoat layer containing fine particles. It can also be seen that the overcoat layer prevents the occurrence of ablation and also prevents the deterioration of printing durability, which is presumed to be the result of image destruction due to ablation.

Examples 5 to 20 A lithographic printing plate precursor was prepared in the same manner as in Example 1 except that the aluminum substrate of Example 1 was replaced with the substrate shown in Table 4. Then, when exposed and printed in the same manner as in Example 1, each of the printing plate precursors exhibited good on-press developability, and good printed matter free from stains was obtained. Table 4 shows the number of on-press development sheets, the number of printing durability sheets, and the number of sheets left unpaid.

Here, the on-press development sheet number is the number of printing sheets required for complete on-press development and represents the difficulty of on-press development property. The number of sheets left unpaid is the amount of printing paper required until a good printed matter without stain is obtained when printing is restarted after stopping the printing machine and leaving the printing plate on the plate cylinder for 1 hour at room temperature. This is the number of sheets, and represents the degree of stain resistance of the printing plate.

[0266]

[Table 4]

From the above results, it was found that the lithographic printing plate precursor according to the invention had good on-press developability, high printing durability and good stain resistance. In all of Examples 5 to 20, no ablation occurred during exposure.

[0268]

According to the present invention, after infrared scanning exposure based on a digital signal, it can be mounted on a printing machine as it is without performing any processing, and printing can be performed. It is possible to provide a heat-sensitive lithographic printing plate precursor that has good printing properties and is excellent in stain resistance during printing, such as ink removal properties.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a radial type cell for electrochemical graining treatment that is preferably used for manufacturing an aluminum substrate of a lithographic printing plate precursor according to the invention.

FIG. 2 is a schematic diagram of a thermocomparator that can be used for measuring the thermal conductivity in the film thickness direction of the hydrophilic film of the lithographic printing plate precursor according to the invention.

[Explanation of symbols]

11 Aluminum plate 12 radial drum roller 13a, 13b Main pole 14 Acidic aqueous solution 15 Solution supply port 16 slits 17 Solution passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 21 Main electrolyzer 22 Auxiliary anode tank 30 thermo comparator 31 chips 32 reservoir 33 Electric heater 34 Heating jacket 35 thermocouple 36 heat sink 37 film 38 Metal substrate 39 Contact thermometer 40 tip temperature recorder 41 Heat sink temperature recorder 42 Reservoir temperature recorder

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C25D 11/18 301 C25D 11/18 301A C25F 3/04 C25F 3/04 A G03F 7/00 503 G03F 7 / 00 503 7/004 521 7/004 521 F-term (reference) 2H025 AA04 AA12 AB03 AC08 AD01 BH03 CC11 DA03 DA18 DA31 2H084 AA13 AE05 AE06 BB02 BB13 CC05 2H096 AA06 BA01 CA03 EA04 2H114 AA04 AA10 AA11 AA14 AA22 AA24 AA27 AA30 BA01 BA10 DA04 DA43 DA46 DA47 DA49 DA52 DA74 EA01 EA02 FA06 FA07 FA10 FA16 GA08 GA09

Claims (12)

[Claims] 1. A surface-roughened aluminum substrate having a hydrophilic film, containing fine particles of a hydrophobic polymer which are combined by heat, a photothermal conversion agent, and a compound which is insoluble in water and has fluidity at 50 ° C. A lithographic printing plate precursor having a lipophilic image forming layer containing no hydrophilic binder resin and further having an overcoat layer containing a water-soluble resin thereon. 2. The lithographic printing plate precursor according to claim 1, wherein the overcoat layer contains at least one fine particle selected from a hydrophobic polymer fine particle and a microcapsule which are coalesced by heat. 3. The overcoat layer contains a photothermal conversion agent, and the optical density at the exposure wavelength of the overcoat layer is lower than the optical density at the exposure wavelength of the image forming layer. Original plate for lithographic printing plate described in. 4. The substrate is subjected to electrochemical graining treatment in an aqueous solution containing hydrochloric acid and has a thermal conductivity of 0.05 to 0.5 W.
4. The lithographic printing plate precursor according to claim 1, which is a substrate having a hydrophilic film of / mK. 5. The substrate is subjected to electrochemical graining treatment in an aqueous solution containing hydrochloric acid, and has a density of 1000 to 3200 kg.
/ M ³ , or a substrate having a hydrophilic film having a porosity of 20 to 70%, The lithographic printing plate precursor as claimed in any one of claims 1 to 3. 6. The substrate has a surface-roughened small pit having an average opening diameter of 0.01 to 3 μm and an average depth of the small pit to the average opening diameter of 0.1 to 0.5. The lithographic printing plate precursor according to any one of claims 1 to 3, which is a substrate having a hydrophilic film having a conductivity of 0.05 to 0.5 W / mK. 7. The substrate has a roughened surface with small pits having an average opening diameter of 0.01 to 3 μm and an average depth of the small pits to the average opening diameter of 0.1 to 0.5. Is 100
0~3200kg / m ^3, or lithographic printing plate precursor as claimed in any of claims 3 to porosity characterized in that it is a substrate having a hydrophilic film 20 to 70%. 8. The average opening diameter of the large waviness of the substrate is 3 to.
It is 20 micrometers, It is characterized by the above-mentioned.
The lithographic printing plate precursor as described in any one of 1. 9. The lithographic printing plate precursor as claimed in claim 1, wherein the hydrophilic film is an anodized film. 10. The lithographic printing plate precursor as claimed in claim 9, wherein the amount of anodized film is 3.2 g / m ² or more. 11. The pore diameter of the surface layer of the anodized film is 40 n.
It is m or less, Claim 9 or Claim 10 characterized by the above-mentioned.
The lithographic printing plate precursor described in. 12. The lithographic printing plate precursor as claimed in claim 9, wherein the anodized film is sealed.