JP2001347768A - Base plate for lighographic printing, manufacturing method thereof as well as processing and printing method employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base plate for lithographic printing plate, excellent in developing property on a machine, high in sensitivity and resistance to printing, and reduced in the deterioration in resistance to printing contamination as well as ink repelling property, and the manufacturing method thereof as well as processing and printing method employing the base plate. SOLUTION: The base plate is provided on an aluminum substrate having an anodized film with a hydrophilic layer containing heat melting hydrophobic thermoplastic polymer grain and hydrophilic binder polymer while micro pores having the diameter of 6-12 nm and average pore interval of 10-30 nm exist in the anodized film. The anodized film, in which the pores having such diameters and average pore intervals exist, is formed by processing the aluminum substrate by the sulfuric acid of 200-500 g/l and, thereafter, the hydrophilic layer is provided thereon to manufacture the base plate. The base plate for lithographic printing is exposed to laser beam and is attached to a printing press or the same is attached at first to the printing press and, thereafter, is exposed to the laser beam on the printing press whereby processing and printing can be effected as. it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor for a computer-to-plate system which does not require development, a method for producing the same, and a plate making and printing method using the same. More specifically, it is possible to record an image by infrared scanning exposure based on a digital signal, and the recorded image can be directly attached to a printing machine and printed without going through a conventional developing process using a liquid. The present invention relates to a possible lithographic printing plate precursor, a method for producing the same, and a plate making and printing method using the same.

[0002]

2. Description of the Related Art Numerous studies have been made on lithographic printing plate precursors for computer-to-plate systems, which have been remarkably progressing in recent years. Among them, as an aim of further streamlining the process and solving the problem of waste liquid treatment, development-free lithographic printing plate precursors that can be mounted on a printing machine and printed without exposure processing have been studied after exposure, Various methods have been proposed. One promising method is a lithographic printing plate precursor in which a hydrophilic layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder polymer is used as an image forming layer.
This method utilizes the fact that when heat is applied to the hydrophilic layer, the hydrophobic thermoplastic polymer particles are fused and the surface of the hydrophilic layer is converted into an lipophilic image area.

[0003] One of the methods for eliminating the processing step is to mount an exposed printing plate precursor on a cylinder of a printing machine and supply a dampening solution and ink while rotating the cylinder. There is a method called on-press development for removing a non-image portion of a plate master. In other words, the printing plate precursor is mounted on a printing machine as it is after exposure, and the processing is completed in a normal printing process. A lithographic printing plate precursor suitable for such on-press development has a photosensitive layer that is soluble in fountain solution and ink solvent, and is suitable for development on a printing machine placed in a bright room. It is required to have a light room handling property.

For example, Japanese Patent No. 2,938,397 discloses a lithographic printing plate precursor in which a photosensitive layer in which fine particles of a thermoplastic hydrophobic polymer are dispersed in a hydrophilic binder polymer is provided on a hydrophilic support. Have been. According to this publication, in the lithographic printing plate precursor, an image is formed by exposing the particles of the thermoplastic hydrophobic polymer by heat with infrared laser exposure, and then the plate is mounted on a printing press cylinder,
It is described that on-press development can be carried out with fountain solution and / or ink. However, in such a method of forming an image by simply coalescing by heat, although good on-press developability is exhibited, the printing durability is low because the adhesive strength between the aluminum support and the image is weak and further the image strength is low. Performance becomes insufficient. JP-A-9-127683 and WO99-
No. 10186 also describes that a printing plate is produced by on-press development after the thermoplastic fine particles are united by heat, but similarly, the adhesion between the aluminum support and the image is weak, and the image strength is also low. However, there is a problem that the printing durability is insufficient.

In order to sufficiently enhance the adhesive force between the photosensitive layer and the support, a phosphoric acid anodic oxide film having micropores having a large diameter is used as a surface treatment of the support for the purpose of enhancing the anchor effect of the photosensitive layer. It is known to use.
Certainly, according to this method, the adhesion between the photosensitive layer and the support is improved. However, since the barrier film is thick and the electrolysis voltage becomes extremely high, more power is required and at the same time, it is difficult to form a uniform film. I will. Furthermore, since the phosphoric acid electrolyte itself causes eutrophication of the river, it is necessary to sufficiently treat the waste liquid. However, this requires a great deal of cost and labor. Currently rarely used.

On the other hand, as a method of increasing the micropores to the same size as the phosphoric acid anodic oxide film by using a commonly used sulfuric acid electrolyte and obtaining the same adhesion as phosphoric acid, the resistance of the charge solution is increased to increase the electrochemical resistance. A method of expanding the pores is known. That is, the sulfuric acid concentration is 50 to 180 g /
This is a method in which anodic oxidation is performed under the condition that the temperature is reduced to about 1 liter and the electrolysis temperature is reduced to about 0 ° C. However, even under such conditions, the micropores are not as large as the phosphoric acid anodic oxide film, and the electrolysis voltage is very high like the phosphoric acid anodic oxide film, requiring a lot of power. There is a problem that it is difficult to form a uniform film, and a current concentration portion called burn occurs at an edge portion to deteriorate surface quality.

Further, Japanese Patent Application Laid-Open No. 8-48020 discloses that
A method is described in which a lipophilic thermosensitive layer is provided on a porous hydrophilic support, exposed to infrared laser, and the lipophilic thermosensitive layer is fixed to a substrate by heat. However, a lipophilic film has poor on-press developability, and there is a problem in that the residue of the lipophilic heat-sensitive layer adheres to an ink roller or printed matter.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithographic printing plate precursor that overcomes the above-mentioned disadvantages of the prior art.
An object of the present invention is to provide a manufacturing method thereof and a plate making and printing method using the same. By selecting the support conditions of the present invention, the pore density,
The pore diameter can be increased to increase the adhesion. That is, a lithographic printing plate precursor having good on-press developability, high sensitivity, and high printing durability, and having little deterioration in printing stains and ink dispensing properties, a method for producing the same, and a plate making using the same. And a printing method.

[0009]

As a result of intensive studies, this object is achieved by the following constitution of the present invention comprising a heat-reactive hydrophilic layer and a support having improved adhesion. That is, the present invention is as follows. (1) On an aluminum support having an anodized film,
A lithographic printing plate precursor having a hydrophilic layer containing hydrophobic thermoplastic polymer particles and a hydrophilic binder polymer that is melted by heat, wherein the diameter of micropores present in the anodized film is 6 to 12 nm, and An original plate for a lithographic printing plate, wherein the average pore interval is 10 to 30 nm. (2) The lithographic printing plate precursor as described in (1) above, further comprising a water-soluble overcoat layer on the hydrophilic layer. (3) The lithographic printing plate precursor as described in (1) or (2) above, further comprising an undercoat layer between the support and the hydrophilic layer. (4) The lithographic printing plate precursor as described in any of (1) to (3) above, wherein at least one of the hydrophilic layer, the overcoat layer, and the undercoat layer contains a photothermal conversion agent.

(5) Anodizing an aluminum support with an aqueous solution of sulfuric acid having a concentration of 200 to 500 g / liter to form a micropore having a diameter of 6 to 12 nm and an average pore interval of 10 to 30 nm on the support. Forming an anodic oxide film in which is present, and providing a hydrophilic layer containing hydrophobic thermoplastic polymer particles and a hydrophilic binder polymer melted by heat on the aluminum support on which the anodic oxide film is formed. Manufacturing method of lithographic printing plate precursor. (6) The temperature of the processing solution in the anodic oxidation treatment is 40 to 6
(5) The method for producing a lithographic printing plate precursor according to the above (5), wherein the temperature is 5 ° C.

(7) On an aluminum support having an anodized film, there is provided a hydrophilic layer containing hydrophobic thermoplastic polymer particles which are melted by heat and a hydrophilic binder polymer. Have a diameter of 6 to 12 nm and an average pore spacing of 10 to 3
The lithographic printing plate precursor characterized in that it is 0 nm is image-exposed with a laser beam and is attached to a printing machine as it is for printing, or after being attached to a printing machine, is exposed to a laser beam on a printing machine and is exposed as it is. A method for making a lithographic printing plate and printing, characterized by printing.

[0012]

Embodiments of the present invention will be described below in detail. [Aluminum support] The aluminum support used in the present invention is a dimensionally stable metal containing aluminum as a main component, and is made of aluminum or an aluminum alloy. In addition to a pure aluminum plate, it is selected from an alloy plate containing aluminum as a main component and containing a trace amount of a different element, or a plastic film or paper on which aluminum (alloy) is laminated or evaporated. In addition, Tokiko Sho 4
A composite sheet in which an aluminum sheet is bonded on a polyethylene terephthalate film as described in JP-A-8-18327 may be used. In the following description, the above-mentioned supports made of aluminum or an aluminum alloy are collectively used as aluminum supports.

The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium and the like. The content of the foreign element in the alloy is 10% by weight or less. It is. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and is conventionally known and used, for example, JIS.
A 1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. can be used as appropriate. The thickness of the aluminum substrate used in the present invention is about 0.1 mm to 0.6 mm. This thickness can be appropriately changed according to the size of the printing press, the size of the printing plate, and the user's request.
The aluminum substrate is appropriately subjected to a substrate surface treatment described below.

[Graining treatment] Examples of the graining method include mechanical graining, chemical etching, and electrolytic grain disclosed in JP-A-56-28893. Furthermore, an electrochemical graining method in which the aluminum surface is electrochemically grained in a hydrochloric acid or nitric acid electrolyte, a wire brush graining method in which the aluminum surface is scratched with a metal wire, and a ball graining method in which the aluminum surface is grained with a polishing ball and an abrasive. Alternatively, a mechanical graining method such as a brush grain method for graining the surface with a nylon brush and an abrasive can be used, and the above graining methods can be used alone or in combination. Among them, a method for producing a surface roughness usefully used in the present invention is an electrochemical method of chemically graining in a hydrochloric acid or nitric acid electrolyte, and a suitable anode electricity quantity is 100 C / dm ^{2 to} 400 C. / Dm ² . More specifically, in an electrolytic solution containing 0.1 to 50% hydrochloric acid or nitric acid, the temperature is 20 to 80 ° C., the time is 1 second to 30 minutes, and the electricity at the time of anode is 100 C / dm ^{2 to} 400 C / d.
It is preferable to perform electrolysis under the condition of m ² .

The grained aluminum substrate is chemically etched with an acid or an alkali. When an acid is used as an etching agent, it takes time to destroy a fine structure, which is disadvantageous in applying the present invention industrially. However, it can be improved by using an alkali as an etching agent. Alkali agents suitably used in the present invention are sodium hydroxide, sodium carbonate,
Sodium aluminate, sodium metasilicate, sodium phosphate,
The preferred ranges of concentration and temperature are 1 to 50% and 20 to 100 ° C, respectively, using potassium hydroxide, lithium hydroxide or the like.
It is.

After the etching, pickling is performed to remove dirt (smut) remaining on the surface. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borofluoric acid and the like are used. In particular, as a method for removing the smut after the electrochemical surface-roughening treatment, it is preferable to use a method described in JP-A-53-12739.
A method of contacting with sulfuric acid of 15 to 65% by weight at a temperature of ９０90 ° C. and a method of alkali etching described in JP-B-48-28123 are exemplified.

[Anodizing treatment] The anodizing treatment of the present invention is applied to the aluminum substrate treated as described above. In the anodizing treatment, sulfuric acid is used as a main component of the electrolytic bath. At this time, the electrolyte may contain at least components normally contained such as an Al alloy plate, an electrode, tap water, and groundwater. Further, the second and third components (Na, K, Mg, L
i, Ca, Ti, Al, V, Cr, Mn, Fe, Co,
Metal ions such as Ni, Cu, Zn and the like, cations such as ammonium ion, nitric acid, carbonic acid, chlorine, phosphoric acid, fluorine,
Anions such as sulfurous acid, titanium, silicic acid, borate ions)
May be added at a concentration of 0 to 10000 ppm or less. In the present invention, the conditions of the anodic oxidation treatment require that the concentration of sulfuric acid in the treatment liquid be 200 to 500 g / l, preferably 250 to 450 g / l, and more preferably 270 to 400 g / l. If the concentration is lower than 200 g / liter, the dissolution rate of the anodic oxide film by the electrolytic solution decreases, and the pore density cannot be obtained to have sufficient adhesion, and the necessary anchor effect cannot be exhibited. On the other hand, when the concentration is higher than 500 g / liter, the dissolution rate approaches the formation rate of the film, so that a high current density and long-time electrolysis are required to obtain a sufficient film thickness, so that more electric power is required. Is needed,
Further, since the amount of dissolution on the film surface is large, the density of the film is lowered, and a hard surface which is hardly worn and which is required by a lithographic printing plate cannot be obtained.

The above-mentioned treatment with the sulfuric acid aqueous solution is carried out at 35 to 70
Can be carried out in a temperature range of 40 ° C.
Within the range, the adhesion of the photosensitive layer can be improved, which is preferable. When the temperature of the electrolytic solution is lower than 35 ° C., the dissolution rate of the anodic oxide film is reduced as in the case where the sulfuric acid concentration is low, and the necessary anchor effect cannot be exhibited. Conversely, when the temperature of the electrolytic solution is higher than 70 ° C., as in the case where the concentration of sulfuric acid is high, the dissolution rate approaches the film formation rate, so that the production efficiency decreases, which is not preferable. The amount of the film formed is 1.0 to 5.0 g.
/ M ² is preferred. Further, the current density in the above-described anodizing treatment can be performed in a normal range, for example, in a range of 1 to 50 A / dm ² . By selecting the above-mentioned appropriate formation conditions, an anodic oxide film having a pore diameter of 6 to 12 nm as viewed from the surface and an average pore interval of 10 to 30 nm can be obtained. The average pore spacing is particularly preferably from 15 to 25 nm.

[Hydrophilic treatment] After the anodizing treatment of the present invention,
If necessary, the surface of the substrate is subjected to a hydrophilic treatment with silicate, polyvinylphosphonic acid, or the like. The film is S
The amount of i or P is 1.5 to 40 mg / m ² , more preferably 4 to 30 mg / m ² . The adhesion amount due to the treatment can be measured by fluorescent X-ray analysis. In the above-mentioned hydrophilic treatment, the alkali metal silicate or polyvinylphosphonic acid is contained in an amount of 0.01 to 30% by weight, preferably 2 to 30% by weight.
The aluminum substrate on which the anodized film is formed is immersed in an aqueous solution having a weight of 15% and a pH of 10 to 13 at 25 ° C, for example, at 15 to 80 ° C for 0.5 to 120 seconds.

As the alkali metal silicate used in the present invention, sodium silicate, potassium silicate, lithium silicate and the like are used. Hydroxides used to increase the pH of the aqueous alkali metal silicate solution include sodium hydroxide, potassium hydroxide, and lithium hydroxide. Incidentally, an alkaline earth metal salt or a Group IVB metal salt may be added to the above-mentioned treatment liquid. Alkaline earth metal salts include nitrates such as calcium nitrate, strontium nitrate, magnesium nitrate, barium nitrate, sulfate, hydrochloride, phosphate, acetate, oxalate,
And water-soluble salts such as borate. Group IVB metal salts include titanium tetrachloride, titanium trichloride, potassium titanium fluoride, titanium potassium oxalate, titanium sulfate, titanium tetraiodide, zirconium chloride, zirconium dioxide, zirconium oxychloride, zirconium tetrachloride, and the like. be able to.

The alkaline earth metal salts or Group IVB metal salts can be used alone or in combination of two or more. The preferred range of these metal salts is 0.01 to 10
% By weight, and a more preferred range is 0.05 to 5.0% by weight. Also, silicate electrodeposition as described in U.S. Pat. No. 3,658,662 is effective. Further, JP-B-46-27481 and JP-A-52-5
No. 8602 and Japanese Patent Application Laid-Open No. 52-30503 are also useful in combination with a support provided with electrolytic grains and a surface treatment combining the above-described anodic oxidation treatment and hydrophilic treatment.

[Hydrophilic undercoat layer] The following hydrophilic undercoat layer can be provided on the aluminum substrate treated as described above, if necessary. Primed with a water-soluble resin, for example, polyvinylphosphonic acid, polymers and copolymers having sulfonic acid groups in side chains, polyacrylic acid, water-soluble metal salts (eg, zinc borate), yellow dyes, amine salts, etc. Those are also suitable. Examples of the organic compound used for the organic (resin) undercoat layer include phosphonic acids having an amino acid such as carboxymethylcellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid.
Optionally substituted phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid,
Organic phosphonic acids such as methylene diphosphonic acid and ethylene diphosphonic acid, organic phosphoric acids such as phenylphosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent, Good organic phosphinic acids such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochlorides of amines having a hydroxyl group such as hydrochloride of triethanolamine. , But may be used as a mixture of two or more.

This organic undercoat layer can be provided by the following method. That is, a method in which a solution obtained by dissolving the above organic compound in water or an organic solvent such as methanol, ethanol, or methyl ethyl ketone or a mixed solvent thereof is applied to an aluminum substrate and dried to form a solution, and water or methanol, ethanol, methyl ethyl ketone, or the like. An aluminum substrate is immersed in a solution obtained by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the organic compound, and then washed with water and dried to form an organic undercoat layer. Is the way. In the former method, a solution of the above organic compound having a concentration of 0.005 to 10% by weight can be applied by various methods. For example, any method such as bar coater coating, spin coating, spray coating, and curtain coating may be used. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight, and the immersion temperature is 20 to 90 ° C.
Preferably, the temperature is 25 to 50 ° C., and the immersion time is 0.1 second to
20 minutes, preferably 2 seconds to 1 minute.

The solution used for this may be a basic substance such as ammonia, triethylamine or potassium hydroxide, hydrochloric acid,
The pH is adjusted with an acidic substance such as phosphoric acid,
2 can be used. Further, a yellow dye can be added for improving the tone reproducibility of the lithographic printing plate precursor. The coating amount of the organic undercoat layer after drying is 2 to 20.
0 mg / m ² is suitable, preferably 5 to 10 mg / m ^2.
m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same is true even if it is larger than 200 mg / m ² . Also, the aluminum support is
A surface treatment such as a dipping treatment in an aqueous solution of potassium fluorozirconate, phosphate or the like may be further performed on the way.

The hydrophilic layer serving as the image forming layer of the present invention contains hydrophobic thermoplastic polymer particles which are melted by heat and a hydrophilic binder polymer.

Examples of the hydrophilic binder polymer include a hydroxyl group, a hydroxyethyl group, a hydroxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, an amide group, a carboxyl group, a carboxymethyl group,
It is selected from polymers having a hydrophilic group such as a carboxylate group.

Specific examples of the hydrophilic binder polymer include gum arabic, casein, gelatin, starch derivatives,
Carboxymethylcellulose and its sodium salt,
Cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, hydroxyethyl acrylate Homopolymers and copolymers, hydroxypropyl 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 the degree of hydrolysis is at least 0 wt%, preferably at least 8
0% by weight of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide, homopolymers and polymers of methacrylamide,
Examples thereof include homopolymers and copolymers of N-methylolacrylamide.

The amount of the hydrophilic binder polymer added to the hydrophilic layer is preferably 5 to 40% by weight based on the solid content of the hydrophilic layer.
0-30% by weight is more preferred. Within this range, good on-press developability and film strength can be obtained.

[0029] The hydrophobic thermoplastic polymer particles used in the hydrophilic layer of the present invention preferably have a solidification temperature of 35 ° C or higher, and more preferably 50 ° C or higher. There is no particular upper limit on the solidification temperature of the thermoplastic hydrophobic polymer particles used in the present invention, but this temperature must be sufficiently lower than the decomposition point of the polymer particles. When the polymer particles are raised above the coagulation temperature, they fuse and coalesce to form hydrophobic agglomerates in the hydrophilic layer. Therefore, these portions become insoluble in water or an aqueous liquid and become ink-receptive.

Specific examples of the hydrophobic polymer constituting the hydrophobic thermoplastic polymer particles used in the hydrophilic layer of the present invention include, for example, ethylene, styrene, vinyl chloride, methyl (meth) acrylate, and ethyl (meth) acrylate. , Vinylidene chloride, acrylonitrile, vinylcarbazole, and other homopolymers or copolymers of monomers or mixtures thereof. Among them, polystyrene and polymethyl methacrylate are particularly preferable.

The weight average molecular weight of the hydrophobic thermoplastic polymer particles used in the hydrophilic layer of the present invention is from 5,000 to 1,000.
It may be in the range of 0,000.

The hydrophobic thermoplastic polymer particles of the present invention have a particle size of 0.01 to 50 μm, more preferably 0.05 to 10 μm.
m, and most preferably from 0.05 to 2 μm.

The amount of hydrophobic thermoplastic polymer particles contained in the hydrophilic layer is preferably between 20 and 65% by weight of the hydrophilic layer solids, and more preferably between 25 and 55% by weight.
And most preferably between 30 and 45% by weight.

The hydrophilic layer of the present invention may contain a crosslinking agent, if necessary. Suitable crosslinking agents include low molecular weight compounds having a methylol group, such as melamine-formaldehyde resin, hydantoin-formaldehyde resin, thiourea-formaldehyde resin, and benzoguanamine-formaldehyde resin.

The hydrophilic layer of the present invention can contain a photothermal conversion agent that absorbs infrared rays and generates heat to improve sensitivity. As such a photothermal conversion agent, 700 to 12
Any light absorbing substance having an absorption band in at least a part of 00 nm may be used, and various pigments, dyes and metal fine particles can be used.

Examples of the type of the pigment include a black pigment, a brown pigment, a red pigment, a violet pigment, a blue pigment, a green pigment, a fluorescent pigment, a metal powder pigment, and a polymer-bound dye. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelated azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments And quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like.

These pigments may be used without surface treatment, or may be used after surface treatment. The method of surface treatment is a method of surface coating a hydrophilic resin or lipophilic resin,
A method of attaching a surfactant, a method of bonding a reactive substance (for example, silica sol, alumina sol, a silane coupling agent, an epoxy compound, an isocyanate compound, and the like) to the surface of the pigment are considered. The above surface treatment method,
It is described in "Properties and Applications of Metallic Soaps" (Koshobo), "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986). Among these pigments, those that absorb infrared rays are preferred because they are suitable for use in lasers that emit infrared rays. As such a pigment absorbing infrared rays, carbon black is preferable. The particle size of the pigment is preferably in the range of 0.01 μm to 1 μm, and more preferably in the range of 0.01 μm to 0.5 μm.

Examples of the dye include commercially available dyes and literatures (for example, “Near-Infrared Absorbing Dyes” in “Dye Handbook” edited by The Society of Synthetic Organic Chemistry, 1975, “Kagaku Kogyo”, May 1986, pp. 45-51). Known dyes described in "Development and Market Trend of Functional Dyes in the 90's", Chapter 2, Section 2.3 (1990), or patents can be used.
Specifically, azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes,
Infrared absorbing dyes such as carbonium dyes, quinone imine dyes, polymethine dyes and cyanine dyes are preferred.

Further, for example, Japanese Patent Application Laid-Open No. 58-12524
No. 6, JP-A-59-84356, JP-A-60-787
No. 87, etc .;
173696, JP-A-58-181690, methine dyes described in JP-A-58-194595, and the like;
JP-A-58-112793, JP-A-58-22479
No. 3, JP-A-59-48187, JP-A-59-739
No. 96, JP-A-60-52940, JP-A-60-63
744, etc .; squarylium dyes described in JP-A-58-112792; cyanine dyes described in British Patent 434,875; and dyes described in U.S. Pat. No. 4,756,993. And cyanine dyes described in U.S. Pat. No. 4,973,572, and dyes described in JP-A-10-268512.

Further, US Pat.
No. 938 is also preferably used, and substituted arylbenzo (thio) pyrylium salts described in U.S. Pat. No. 3,881,924;
No. 42645, trimethinethiapyrylium salts, JP-A-58-181051, JP-A-58-220143, JP-A-59-41363, JP-A-59-84248, and JP-A-59-84248.
No. 84249, No. 59-146063, No. 59-14
No. 6061, pyranium compounds described in JP-A-59-216146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and Japanese Patent Publication No. 5-135514, 5-1-1970
No. 2, a pyrylium compound, Eporin III-178, Epolite III-130 manufactured by Eporin,
Epolite III-125 and the like are also preferably used. Some specific examples are shown below.

[0041]

Embedded image

[0042]

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The above-mentioned organic photothermal conversion agent can be added up to 30% by weight in the hydrophilic layer. Preferably 5
The content is 25% by weight, particularly preferably 7 to 20% by weight. Within this range, good sensitivity is obtained.

In the hydrophilic layer of the present invention, fine metal particles can be used as a photothermal conversion agent. Most of the metal fine particles are light-heat converting and self-heating, but preferred metal fine particles include Si, Al, Ti, V, Cr, and M.
n, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo,
Ag, Au, Pt, Pd, Rh, In, Sn, W, T
e, Pb, Ge, Re, and Sb alone or as an alloy, or fine particles of oxides or sulfides thereof. Among the metals constituting these metal fine particles, preferred metals are those which are liable to be coalesced by heat at the time of light irradiation, and have a melting point of about 1000 ° C. or less and have absorption in the infrared, visible or ultraviolet region, for example, Re, Sb, Te, Au, A
g, Cu, Ge, Pb and Sn. Particularly preferred are metal fine particles having a relatively low melting point and a relatively high absorbance to infrared rays, for example, Ag, Au, C
Among u, Sb, Ge and Pb, the most preferred elements include Ag, Au and Cu.

Further, for example, Re, Sb, Te, Au, A
g, Cu, Ge, Pb, Sn and other low melting point metal particles and self-heating metal particles such as Ti, Cr, Fe, Co, Ni, W and Ge. It may be made of a light-to-heat conversion material. Also, Ag,
It is also preferable to use a combination of a metal-type micro-piece and a metal-type micro-piece having a particularly large light absorption when made into a micro-piece such as Pt or Pd.

The size of these particles is preferably 10 μm.
m, more preferably 0.003 to 5 μm, particularly preferably 0.01 to 3 μm. The finer the particle, the lower the coagulation temperature, that is, the higher the light sensitivity in the heat mode, which is advantageous. However, it is difficult to disperse the particles.
Above μm, the resolution of the printed matter deteriorates.

When metal fine particles are used as the light-to-heat conversion agent, the amount added is 10% by weight or more of the solid content of the hydrophilic layer, preferably 20% by weight or more, particularly preferably 30% by weight or more. If it is less than 10% by weight, the sensitivity will be low.

The photothermal conversion agent may contain an undercoat layer adjacent to the hydrophilic layer or a water-soluble overcoat layer described later. By at least one of the hydrophilic layer, the undercoat layer and the overcoat layer contains a photothermal conversion agent,
Infrared absorption efficiency is increased, and sensitivity can be improved.

Various compounds other than the above may be added to the hydrophilic layer of the present invention, if necessary. For example, a polyfunctional monomer can be added to the hydrophilic layer matrix to further improve the printing durability. For example, to make it easy to distinguish between an image part and a non-image part after image formation,
Dyes having large absorption in the visible light region can be used as colorants for images. Specifically, Oil Yellow #
101, oil yellow # 103, oil pink # 31
2. Oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (all manufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue, crystal violet (CI42555), methyl Violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI
42000), methylene blue (CI52015), etc.
And dyes described in JP-A-62-293247. Further, pigments such as phthalocyanine pigments, azo pigments, and titanium oxide can also be suitably used. The amount of addition is 0.01 to 10% by weight based on the total solid content of the hydrophilic layer coating solution.

Further, a plasticizer may be added to the hydrophilic layer of the present invention, if necessary, to impart flexibility and the like to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate,
Dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, and the like are used.

The hydrophilic layer of the present invention is applied on the hydrophilic layer by dissolving each of the necessary components described above in a solvent to prepare a coating solution.
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-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyl lactone, toluene, water and the like,
It is not limited to this. These solvents are used alone or as a mixture. The solid content concentration of the coating solution is preferably 1 to 50% by weight.

The coating amount (solid content) of the hydrophilic layer on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.5 to 5.0 g / m ² . When the coating amount is smaller than this range, the apparent sensitivity is increased, but the film characteristics of the hydrophilic layer that performs the function of image recording are reduced. Various methods can be used as a method of applying. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating,
Examples include blade coating and roll coating.

The hydrophilic layer coating solution according to the present invention may contain a surfactant for improving coating properties, for example, a surfactant described in
A fluorinated surfactant as described in JP 170950 can be added. A preferable addition amount is 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight of the total solid content of the hydrophilic layer.

In the lithographic printing plate precursor according to the present invention, a water-soluble overcoat layer can be provided on the hydrophilic layer in order to prevent contamination of the hydrophilic layer surface with lipophilic substances. The water-soluble overcoat layer used in the present invention can be easily removed at the time of printing and contains a resin selected from water-soluble organic polymer compounds. As the water-soluble organic polymer compound used here, a film formed by coating and drying has a film-forming ability, specifically, polyvinyl acetate (having a hydrolysis rate of 65% or more), polyacrylic Acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal salt or amine Salt, polyacrylamide and its copolymer, polyhydroxyethyl acrylate, polyvinylpyrrolidone and its copolymer, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamide-2-methyl-
1-propanesulfonic acid and its alkali metal salt or amine salt, poly-2-acrylamido-2-methyl-1
-Propanesulfonic acid copolymers and alkali metal salts or amine salts thereof, gum arabic, cellulose derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof,
Examples include white dextrin, pullulan, and enzymatically degraded etherified dextrin. Further, according to the purpose, two or more of these resins can be used in combination.

The above-mentioned water-soluble or water-dispersible photothermal conversion agent may be added to the overcoat layer. Furthermore, in the case of aqueous solution application, a nonionic surfactant such as polyoxyethylene nonylphenyl ether and polyoxyethylene dodecyl ether can be added to the overcoat layer in order to ensure uniformity of application. . The dry coating amount of the overcoat layer is 0.1 to 2.0
g / m ² is preferred. Within this range, excellent contamination of the hydrophilic layer surface with lipophilic substances such as fingerprints can be prevented without impairing the on-press developability.

The lithographic printing plate precursor of the present invention forms an image by heat. Specifically, direct image-like recording using a thermal recording head or the like, scanning exposure using an infrared laser, high-intensity flash exposure such as a xenon discharge lamp, or infrared lamp exposure is used. Semiconductors that emit infrared light having a wavelength of 700 to 1200 nm are used. Exposure with a solid-state high-output infrared laser such as a laser or a YAG laser is preferable. The lithographic printing plate precursor of the present invention, which has been image-exposed, can be mounted on a printing press without further processing, and can be printed in a usual procedure using ink and fountain solution. Further, as described in Japanese Patent No. 2938398, these lithographic printing plate precursors are mounted on a printing press cylinder, exposed to a laser mounted on the printing press, and then exposed to a fountain solution and / or Alternatively, it is also possible to carry out on-press development with ink. These lithographic printing plate precursors can also be used for printing after development using water or an appropriate aqueous solution as a developing solution.

[0057]

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

[Preparation of Support] (1) Supports 1 to 7 (and Supports 1 to 3 for Comparative Example) An aluminum plate made of a material 1050 having a thickness of 0.24 mm and 10
After immersing in 70% sodium hydroxide at 70 ° C. for 60 seconds for etching, the substrate was washed with running water, neutralized with 20% HNO ₃ , and washed with water. This was conducted in a 1% aqueous nitric acid solution at a current density of 20 A / dm ² using a rectangular wave current of 60 Hz.
Electrolytic surface roughening was performed at an anode charge of 70 C / dm ² .
After washing with water, it was immersed in a 25% aqueous sodium hydroxide solution at 30 ° C. for 3 seconds to perform etching. After washing with running water, it was immersed in a 30% sulfuric acid aqueous solution and desmutted at 55 ° C. for 20 seconds. Next, it was anodized under the conditions shown in Table 1 below, and then washed with water. The anodizing treatment was performed under a current density condition of 20 A / dm ² , and the amount of each anodized film was adjusted to 2.7 g / m ² by adjusting the electrolysis time.

No. 3 sodium silicate (SiO ₂ = 28 to
(2.5% by weight of 30%, Na ₂ O = 9 to 10%, Fe = 0.02% or less), pH = 11.2, 70 ° C. for 13 seconds, followed by washing with water.

[Method of Measuring Pore Diameter and Pore Interval] Hitachi S-
Observation was performed at 150,000 times with a 900 scanning electron microscope. The pore diameter was visually read from the obtained image, and the average value of 20 pores was determined to be the pore diameter. Regarding the pore spacing, first, attention is paid to one pore, the distance from the center to each center from the closest pore to the sixth closest pore is measured, and the average of the measured values is obtained. An average value was similarly obtained for each of the 10 pores, and the 10 values thus obtained were further averaged to obtain a pore interval.

[0061]

[Table 1]

Examples 1 to 7 and Comparative Examples 1 to 3 A hydrophilic layer coating solution prepared as described below was coated on an aluminum support shown in Table 1 at a coating solution amount of 30 g / m ² , And dried for 60 seconds at a dry coating amount of 1.0 g /
m ² of a hydrophilic layer was provided.

(Preparation of Hydrophilic Layer Coating Solution) Polystyrene dispersed in water with a nonionic surfactant (Tg 110 ° C.,
To 5 g of a 20% by weight dispersion having an average particle diameter of 80 nm, 0.02 g of polyoxyethylene nonylphenyl ether and 15.5 g of water were added, and finally, 5% by weight of polyvinyl alcohol (PVA205 manufactured by Kuraray Co., Ltd.) was stirred. 5 g of aqueous solution are added.

On the hydrophilic layer thus prepared, an overcoat layer coating solution having the following composition was applied in an amount of 10 g / m ^2.
And dried at 100 ° C. for 60 seconds to prepare a lithographic printing plate precursor having an overcoat layer having a dry coating weight of 0.5 g / m ² .

(Coating Solution for Overcoat Layer) Polyacrylic acid (weight average molecular weight: 20,000) 1 g 20% by weight ethanol dispersion of carbon black stabilized with a nonionic surfactant 2.5 g 26.5 g methanol

The lithographic printing plate precursor thus obtained was used as a trend setter (830 W of 40 W, manufactured by Creo Corporation, Canada).
m, a plate setter equipped with a semiconductor laser) and exposed with energy of 40 mJ / cm ² . The exposed plate was directly mounted on a Harris Aurelia printing press without any further processing, and printing was performed using a fountain solution containing a 10% by volume aqueous solution of isopropyl alcohol containing an etchant and ink. Table 2 shows the results.

[0067]

[Table 2]

From the above results, the lithographic printing plate precursor according to the present invention was able to obtain a plate having high printing durability without deteriorating the stain resistance.

Examples 8 to 14 and Comparative Examples 4 to 6 Instead of the polystyrene fine particles used in the hydrophilic layers of Examples 1 to 7 and Comparative Examples 1 to 3, polymethyl methacrylate fine particles (Tg 90 ° C., average particle diameter 90 nm) ) And 0.4 g of an infrared absorbing dye (IR-11). Except for this, lithographic printing plate precursors were prepared in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 3. The lithographic printing plate precursor thus obtained was exposed and printed in the same manner as in Example 1. As a result, as shown in Table 3, the lithographic printing plate precursor of the present invention was able to obtain a printed matter free of dirt.

[0070]

[Table 3]

[0071]

According to the present invention, an on-press development type lithographic printing plate precursor that can be mounted on a printing press as it is after exposure and has good on-press developability overcoming the disadvantages of the prior art. There is obtained a lithographic printing plate precursor having good stain resistance and high printing durability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/09 501 G03F 7/09 501 7/11 7/11 (72) Inventor Hisashi Hotta Haibara-gun, Shizuoka 4,000 Kawajiri, Yoshida-cho F-term in Fujisha Shin Film Co., Ltd. (Reference) 2H025 AA01 AA12 AB03 AC08 AD01 AD03 CC20 DA02 DA18 DA20 DA36 2H084 AA14 AA17 AA38 CC05 2H096 AA07 BA16 CA03 CA05 CA20 EA04 LA16 2A114 AAA A21 A21 BA10 DA03 DA04 DA08 DA11 DA34 DA42 DA43 DA44 DA46 DA48 DA50 DA52 DA53 DA56 DA64 DA75 DA79 EA01 EA03 EA05 EA08 FA01 FA06 FA18 GA09

Claims (7)

[Claims] 1. A lithographic printing plate precursor comprising, on an aluminum support having an anodic oxide film, a hydrophilic layer containing hydrophobic thermoplastic polymer particles melted by heat and a hydrophilic binder polymer, wherein the anodic oxidation A lithographic printing plate precursor characterized in that the micropores present in the coating have a diameter of 6 to 12 nm and an average pore spacing of 10 to 30 nm. 2. The lithographic printing plate precursor according to claim 1, further comprising a water-soluble overcoat layer on the hydrophilic layer. 3. The lithographic printing plate precursor according to claim 1, further comprising an undercoat layer between the support and the hydrophilic layer. 4. The lithographic printing plate precursor according to claim 1, wherein at least one of the hydrophilic layer, the overcoat layer and the undercoat layer contains a photothermal conversion agent. 5. Anodizing an aluminum support with an aqueous solution of sulfuric acid having a concentration of 200 to 500 g / l to form micropores having a diameter of 6 to 12 nm and an average pore interval of 10 to 30 nm on the support. A lithographic plate comprising: forming an existing anodic oxide film; and providing a hydrophilic layer containing hydrophobic thermoplastic polymer particles and a hydrophilic binder polymer melted by heat on the aluminum support on which the anodic oxide film is formed. Manufacturing method of printing plate precursor. 6. The method for producing a lithographic printing plate precursor according to claim 5, wherein the temperature of the processing solution in the anodic oxidation treatment is 40 to 65 ° C. 7. An aluminum support having an anodized film, comprising a hydrophilic layer containing hydrophobic thermoplastic polymer particles that are melted by heat and a hydrophilic binder polymer, wherein a micropore existing in the anodized film is provided. The diameter is 6 to 12 nm, and the average pore spacing is 10 to 30 n.
m, the image of the lithographic printing plate precursor is image-exposed with a laser beam and mounted on a printing machine for printing, or after being mounted on the printing machine, exposed on a printing machine with a laser beam and printed as it is. Plate making and printing method for lithographic printing plate.