JP2007245541A - Lithographic printing plate material and method for manufacturing lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithographic printing plate material excellent in printability, on-machine developing properties and printing wear, and a method for manufacturing a lithographic printing plate using it. <P>SOLUTION: The lithographic printing plate material having an image forming layer comprising at least one selected from a hot-melt particle and a microcapsule and a water-soluble resin on a hydrophilic substrate, is characterized in that a water solution with 10 mass% at 25°C has a viscosity of 50×10<SP>-3</SP>Pa s to 1,000×10<SP>-3</SP>Pa s. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate material and a method for producing a lithographic printing plate using the lithographic printing plate material.

  In recent years, in synchronization with the spread of computers for printing data, CTP technology for directly inputting images to a PS plate using a semiconductor laser via a computer based on digital image data is also simplified in process and cost. Has been attracting attention. In view of dealing with environmental problems and reducing office space, development of so-called processless CTP technology that does not require processing with a developer (no need for an automatic developing machine) is remarkable. As a processless CTP technique, a lithographic printing plate material in which a heat-sensitive layer containing heat-fusible particles dispersed by a hydrophilic resin is laminated on a hydrophilic support for lithographic printing plate printing (see Patent Documents 1 and 2) A lithographic printing plate material having an image forming layer containing microcapsules on a hydrophilic support for a lithographic printing plate (see Patent Document 3) is disclosed.

  In recent years, the printing industry has been required to perform various types of printing in a short time, and lithographic printing plate materials are required to have good on-press developability and high-speed printing suitability. Under high speed printing, printing durability generally decreases and the amount of dampening water supplied to the printing plate tends to increase. For this reason, it is necessary for the future processless planographic printing plate material to have a balance between good on-machine developability, high printing durability, and good printability.

For the purpose of achieving both on-press developability and printing durability, it has been disclosed to select a hydrophilic resin in the image forming layer that has both the crosslinkability of the exposed area and the hydrophilic property (patent) In the current printing industry, there is a problem that sufficient performance cannot be secured.
Japanese Patent No. 293888397 Japanese Patent No. 293897 JP 2004-50745 A JP-A-9-171250

  The present invention has been made in view of the above problems, and an object of the present invention is to produce a lithographic printing plate material having excellent printability, excellent on-press developability and printing durability, and a lithographic printing plate using the same. It is to provide a method.

  The above object of the present invention can be achieved by the following constitution.

1. A lithographic printing plate material having, on a hydrophilic support, an image forming layer containing at least one selected from heat-meltable particles and microcapsules and a water-soluble resin, wherein the water-soluble resin is 25 ° C A lithographic printing plate material, wherein the 10% by mass aqueous solution is from 50 × 10 ⁻³ Pa · s to 1000 × 10 ⁻³ Pa · s.

  2. A method for producing a lithographic printing plate, comprising developing the lithographic printing plate material described in 2.1 by supplying dampening water and ink on a cylinder of a printing machine.

  According to the present invention, it is possible to provide a lithographic printing plate material having excellent printability, excellent on-press developability and printing durability, and a method for producing a lithographic printing plate using the same.

  Hereinafter, although the best mode for carrying out the present invention will be described, the present invention is not limited to these.

(Hydrophilic binder)
The lithographic printing plate material of the present invention contains a water-soluble resin in its image forming layer. As a characteristic of a preferable water-soluble resin, a 10% by mass aqueous solution at 25 ° C. has a viscosity of 50 × 10 ⁻³ Pa · s to 1000 × 10 ⁻³ Pa · s. The inventor has accumulated research and found that the viscosity of a water-soluble resin in an aqueous solution correlates with the on-press developability, printing durability, and printability of a lithographic printing plate material. The mechanism of the correlation is not clear, but when the image forming layer is applied and dried, the water-soluble resin around the heat-meltable particles and microcapsules suppresses the close proximity of the heat-meltable particles and microcapsules due to the viscosity. Presumed to be uniformly dispersed. That is, when the viscosity of the 10% by weight aqueous solution of the hydrophilic binder is 50 × 10 ⁻³ Pa · s or less, the viscosity of the image forming layer coating liquid at the time of coating and drying of the image forming layer becomes low, and the heat-meltable particles and macrocapsules Aggregation tends to proceed, and the on-press developability and printability are likely to deteriorate. On the other hand, if it exceeds 1000 × 10 ⁻³ Pa · s, the on-press developability deteriorates because the solubility of the water-soluble resin in the dried image forming layer is low. In addition, the viscosity of the water-soluble resin fluctuates in synchronism with the heat-melting characteristics, and the water-soluble resin inhibits the fusion of the heat-meltable particles and the microcapsule reaction during image exposure. There is a decline.

  As the hydrophilic binder used in the present invention, for example, those having a hydrophilic group such as hydroxyl group, carboxyl group, hydroxyethyl group, hydroxypropyl group, amino group, aminoethyl group, aminopropyl group, carboxymethyl group are preferable.

  Specific hydrophilic binders include gum arabic, casein, gelatin, starch derivatives, carboxymethyl cellulose and their Na salts, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids And salts thereof, polymethacrylic acids and salts thereof, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypropyl methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxy Homopolymers and copolymers of butyl methacrylate, homopolymers and copolymers of hydroxybutyl acrylate, poly Tylene glycols, hydroxypropylene polymers, polyvinyl alcohols, and homopolymers and copolymers of hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, N-methylol acrylamide having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight Etc.

  It is preferable that 2-40 mass% of hydrophilic polymers are contained in a thermosensitive layer, and it is more preferable that 3-30 mass% is contained.

In the present invention, in order that the 10 mass% aqueous solution at 25 ° C. has a viscosity of 50 × 10 ⁻³ Pa · s to 1000 × 10 ⁻³ Pa · s, it can be achieved by appropriately selecting the molecular weight of the above-described resin. .

(Microcapsule)
In the present invention, the image forming layer contains at least one selected from microcapsules and heat-meltable particles and a water-soluble resin.

  The microcapsule encapsulating the lipophilic compound having a thermoreactive group of the present invention (hereinafter also simply referred to as a thermoreactive compound), which is preferably used as the microcapsule according to the present invention, has a microcapsule via the thermoreactive group. It is good also as a structure which can react between capsules, and it is good also as a structure which can react with the low molecular compound contained as a hydrophilic resin or other additive added in the heat sensitive layer. Alternatively, two or more types of microcapsules may have a heat-reactive group capable of reacting with each other to allow the microcapsules to react with each other.

  The microcapsules encapsulating the heat-reactive compound of the present invention include a microcapsule containing a heat-reactive compound in the microcapsule, a heat-reactive compound introduced into the outer wall of the microcapsule, and a heat-reactive property In which the compound is introduced into the outer wall of the microcapsule at the same time.

  The above-mentioned thermally reactive group may be any functional group that undergoes any reaction as long as a chemical bond is formed, but an ethylenically unsaturated group that undergoes a radical polymerization reaction (for example, acryloyl group, methacryloyl group, vinyl). Groups, allyl groups, etc.), cationically polymerizable groups (eg, vinyl groups, vinyloxy groups, etc.), isocyanate groups that perform addition reactions or their block bodies, epoxy groups, vinyloxy groups, and active hydrogen atoms that are reaction partners thereof. Functional group (for example, amino group, hydroxyl group, carboxyl group, etc.), carboxyl group that performs condensation reaction, hydroxyl group or amino group that is the reaction partner, acid anhydride that performs ring-opening addition reaction, and reaction partner An amino group, a hydroxyl group, etc. can be mentioned as a suitable thing. Hereinafter, the lipophilic compound having a thermally reactive functional group will be described in more detail.

  Preferred examples of the compound having a radically polymerizable unsaturated group include a compound having at least one, preferably two or more, ethylenically unsaturated bonds such as acryloyl group, methacryloyl group, vinyl group and allyl group. . Such a compound group is widely known as a monomer or a crosslinking agent for a photopolymerizable or thermopolymerizable composition in the industrial field, and can be used without any particular limitation in the present invention. . The chemical form is a monomer, a prepolymer, that is, a dimer, a trimer, an oligomer, a polymer or a copolymer, or a mixture thereof.

  Examples of the compound having a radically polymerizable unsaturated group suitable for the present invention include compounds described in JP-A No. 2001-277740 as a compound having a polymerizable unsaturated group. Representative compound examples include trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, Dipentaerythritol di (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, adduct of trimethylolpropane diacrylate and xylylene diisocyanate, copolymer of allyl methacrylate (for example , Allyl methacrylate / methacrylic acid copolymer, allyl methacrylate / ethyl methacrylate copolymer, allyl methacrylate / butyl methacrylate copolymer Etc.), and the like. However, it is not limited to these examples.

  Examples of the compound having a vinyloxy group suitable for the present invention include compounds described in JP-A-2002-29162. Specific examples include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,3-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trimethylolethane trivinyl ether, hexane. Diol divinyl ether, 1,4-cyclohexanediol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, ethylene glycol diethylene vinyl ether, triethylene glycol Coal diethylene vinyl ether, ethylene glycol dipropylene vinyl ether, trimethylolpropane triethylene vinyl ether, trimethylolpropane diethylene vinyl ether, pentaerythritol diethylene vinyl ether, pentaerythritol triethylene vinyl ether, pentaerythritol tetraethylene vinyl ether, 1,2-bis (vinyloxymethoxy) Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,4-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3 , 5-tris {2- (vinyloxy) ethyloxy} benzene, 4,4′-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5 -Bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, 2,5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane, 2,2-bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane and the like. It is not limited to these.

  As the compound having an epoxy group suitable for the present invention, a compound having two or more epoxy groups is preferable, and a glycidyl ether compound obtained by reaction of a polyhydric alcohol or a polyhydric phenol with epichlorohydrin or a prepolymer thereof. Furthermore, a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate can be used.

  Preferable specific examples include glycerin polyglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether and the like. Polyglycidyl ethers of bisphenols or polyphenols or hydrogenated products thereof, for example, diglycidyl ether of hydrogenated bisphenol A, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, diglycidyl ether of bisphenol A, or epichlorohydrin Polyaddition, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether or epichlorohydrin polyadduct of halogenated bisphenol A, diglycidyl ether or epichlorohydrin polyaddition of biphenyl type bisphenol And glycidyl etherified products of novolak resins are also preferred. Further, methyl methacrylate / glycidyl methacrylate copolymer, ethyl methacrylate / glycidyl methacrylate copolymer and the like are also preferable.

  Commercially available products of the above compounds include, for example, Epicoat 1001 (molecular weight: about 900, epoxy equivalent: 450 to 500), Epicoat 1002 (molecular weight: about 1600, epoxy equivalent: 600 to 700), Epicoat 1004 (about 1060, epoxy equivalent 875-975), Epicoat 1007 (molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009 (molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010 (molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100L (epoxy equivalent) 4000), Epicoat YX31575 (epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195XL, ESCN-195XF, and the like.

  Suitable isocyanate compounds for the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diisocyanate, Examples include hexamethylene diisocyanate, cyclohexyl diisocyanate, and compounds obtained by blocking these with alcohol or amine.

Suitable amine compounds for the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, polyethyleneimine and the like.
Examples of the compound having a hydroxyl group suitable for the present invention include a compound having a terminal methylol group, a polyhydric alcohol such as pentaerythritol, and bisphenol / polyphenols.

  Examples of the compound having a carboxyl group suitable for the present invention include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid.

  Suitable acid anhydrides for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  A known method can be applied as a method for microencapsulating the lipophilic compound having the thermoreactive group. For example, as a method for producing microcapsules, US Pat. No. 2,800,547, US Pat. No. 2,800,498, a method using coacervation, British Patent No. 990443, US Pat. No. 3,287,154 No. 38-19574, Japanese Patent Publication No. 42-446, Japanese Patent Publication No. 42-711, a method by an interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304. US Pat. No. 4,996,669, US Pat. No. 3,796,669, an isocyanate polyol wall material, US Pat. No. 3,914,511, an isocyanate wall material, US Pat. No. 4,001,140 , US Pat. No. 4,087,376, US A method using a urea-formaldehyde-based or urea-formaldehyde-resorcinol-based wall forming material found in Japanese Patent No. 4089802, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose found in US Pat. No. 4,025,445 In Situ Method by Monomer Polymerization as Seen Japanese Patent Publication Nos. 36-9163 and 51-9079, British Patent No. 930422, US Pat. No. 3,111,407, Spray Drying Method, British Patent No. 952807 and British Patent No. 967074, such as electrolytic dispersion cooling.

  A preferable microcapsule wall of the microcapsule used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane.

  In the microencapsulation method, a protective colloid of a microcapsule solution is used as necessary. As the protective colloid, natural or synthetic hydrophilic polymers such as gelatin, gum arabic, casein, carboxymethylcellulose, starch, polyvinyl alcohol and the like are used. The amount of the protective colloid used is preferably 5 to 20% by mass of the solid content of the microcapsule dispersion. These protective colloids have an action of promoting on-press developability of the lithographic printing plate precursor.

  The amount of the microcapsule added to the heat sensitive layer is preferably 50% by mass or more, more preferably 60% by mass or more, based on the solid content of the heat sensitive layer. Within this range, good sensitivity, printing durability and printability can be obtained.

(Hot-melting particles)
In the present invention, the image forming layer contains at least one selected from hot-melt particles and microcapsules and a water-soluble resin.

As the heat-melting substance constituting the above-mentioned heat-fusible fine particles, a substance having a melting point of 60 ° C. or more and 150 ° C. or less and a viscosity at melting of 20 × 10 ⁻³ Pa · s or less is preferably used.

  Specifically, paraffin wax, polyolefin wax, polyethylene wax, polypropylene wax, microcrystalline wax, fatty acid wax, fatty acid ester wax, Fischer-Tropsch wax, amide wax, rosin modified phenol resin, terpene modified phenol resin. Coumarin-indene resin can be used.

  Of these, carnauba wax, which is a fatty acid ester wax, is preferable because it has a low viscosity at the time of heat melting and a high hardness at room temperature, and therefore has excellent laser exposure sensitivity, resolution, and image durability.

  As a method for making the heat-meltable substance into fine particles, a known method can be used, and a macroencapsulation method can be mentioned.

  As the thermoplastic resin constituting the heat fusion fine particles, those having a softening point of 40 ° C. or higher and 120 ° C. or lower and a melting point of 60 ° C. or higher and 150 ° C. or lower are suitably used.

  Specifically, diene polymers such as polypropylene, polybutadiene, polyisoprene, ethylene-butadiene copolymer, synthetic rubbers such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, Examples include (meth) acrylic acid ester copolymers, polystyrene, polyvinyl chloride, polyesters, polyurethanes and the like, which contain methyl methacrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile and the like as constituent components.

Among these, the copolymer of (meth) acrylic acid ester-styrene is particularly excellent in laser exposure sensitivity, resolution, and image durability in that it has a high thermal melting behavior (thermal responsiveness) and high hardness.
As a method for making the thermoplastic resin into fine particles, a known method can be used, and examples thereof include an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a gas phase polymerization method.

  The average particle size of the heat-fusible particles is preferably 0.01 to 2 μm, more preferably 0.1 to 1.0 μm. If it is smaller than this range, water developability and developability using dampening water and / or printing ink on the printing press deteriorate, and if it exceeds this range, laser exposure sensitivity and image durability deteriorate. It can be seen.

(Photothermal conversion material)
The heat-sensitive layer of the present invention preferably contains a converted photothermal conversion agent material that absorbs electromagnetic waves and generates heat. Examples of the photothermal conversion agent include infrared absorbing dyes, pigments, metals, and metal oxides.

  Examples of infrared absorbing dyes include organic dyes such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, which are general infrared absorbing dyes. Examples thereof include compounds, phthalocyanine-based, naphthalocyanine-based, azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes.

  Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-280750, JP-A-1-293342, JP-A-2-2074, JP-A-3-26593, 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, 7 -43851, 7-102179, JP-A-2001-117201, and the like. These can be used alone or in combination of two or more.

  Examples of the pigment include carbon, graphite, metal, metal oxide and the like.

  As carbon, furnace black or acetylene black is particularly preferable. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.

  As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.

  As the metal, any metal can be used as long as the particle diameter is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less. The shape may be any shape such as a spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.

As the metal oxide, a material that is black in the visible light region or a material that is conductive or that is a semiconductor can be used. Examples of the material exhibiting black color in the visible light region include black iron oxide (Fe ₃ O ₄ ) and black mixed metal oxides containing two or more of the aforementioned metals. The metal oxide is a black complex metal oxide composed of two or more kinds of metal oxides. Specifically, it is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. These can be produced by the methods disclosed in JP-A-8-27393, 9-25126, 9-237570, 9-241529, and 10-231441. The composite metal oxide that can be used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, have good photothermal conversion efficiency. These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better. However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better.

Examples of materials that have conductivity or are semiconductors include reduced Sb-doped SnO ₂ (ATO), Sn-added In ₂ O ₃ (ITO), TiO ₂ , and TiO ₂ . Examples thereof include TiO (titanium oxynitride, generally titanium black). Further, it is also possible to use those obtained by coating the core material _{(BaSO 4, TiO 2, 9Al} 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) in these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.

  A particularly preferable embodiment of the photothermal conversion material is that the infrared absorbing dye and the metal oxide are black complex metal oxides composed of two or more metal oxides.

  The content of these photothermal conversion agents in the image forming layer is preferably 1 to 20% by mass.

(Hydrophilic support)
Next, the hydrophilic support used in the present invention will be described.
As the hydrophilic support that can be used in the present invention, an aluminum substrate made of aluminum or an aluminum alloy (hereinafter also referred to as aluminum) is used because of the relationship between specific gravity and rigidity. Various aluminum alloys can be used. For example, an alloy of a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum is used. The thickness of the aluminum substrate is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

  The aluminum substrate used in the present invention is more preferably one that has been subjected to any of the known roughening treatment, anodizing treatment, or surface hydrophilization treatment, that is, aluminum grain. The aluminum grain may be produced by any method, but one of the production methods for obtaining the surface shape defined in the present invention is the method disclosed in JP-A-10-869. Can do.

  The aluminum substrate according to the present invention is preferably subjected to a degreasing treatment in order to remove the rolling oil on the surface prior to roughening (graining treatment). As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is generated on the surface of the aluminum base material. In this case, it is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof. It is preferable to perform a desmut treatment.

Examples of the roughening method include a mechanical method and a method of etching by electrolysis. The mechanical roughening method used is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The roughening by the brush polishing method is, for example, by rotating a rotating brush using brush bristles having a diameter of 0.2 to 0.8 mm, and watering, for example, volcanic ash particles having a particle size of 10 to 100 μm on the surface of the aluminum substrate. While supplying the slurry dispersed uniformly, the brush can be pressed. The roughening by honing polishing is performed by, for example, uniformly dispersing volcanic ash particles having a particle size of 10 to 100 μm in water, injecting the pressure from a nozzle and injecting it obliquely to the surface of the aluminum base material. be able to. Also, for example, abrasive particles having a particle diameter of 10 to 100 μm are present on the surface of the aluminum substrate at a density of 2.5 × 10 ³ to 10 × 10 ³ particles / cm ² at intervals of 100 to 200 μm. Roughening can also be performed by laminating the coated sheets and transferring the rough surface pattern of the sheet by applying pressure.

After roughening by the above-mentioned mechanical roughening method, it is preferable to immerse in an aqueous solution of acid or alkali in order to remove the abrasive that has digged into the surface of the aluminum substrate, formed aluminum scraps and the like. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an aqueous alkali solution such as sodium hydroxide. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. After the immersion treatment with an alkaline aqueous solution, it is preferable to carry out a neutralization treatment by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

Although the electrochemical surface roughening method is not particularly limited, a method of electrochemical surface roughening in an acidic electrolyte is preferable. As the acidic electrolytic solution, an acidic electrolytic solution usually used in an electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolytic solution is preferably used. As the electrochemical surface roughening method, for example, methods described in Japanese Patent Publication No. 48-28123, British Patent No. 896,563 and Japanese Patent Laid-Open No. 53-67507 can be used. This roughening method can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C.

When electrochemical surface roughening is performed using a nitric acid-based electrolyte as the electrolyte, it can be generally performed by applying a voltage in the range of 1 to 50 volts, but is selected from the range of 10 to 30 volts. Is preferred. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 20 to 100 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of nitric acid in the electrolytic solution is preferably 0.1 to 5% by mass. 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.

When a hydrochloric acid-based electrolyte is used as the electrolyte, it can be generally applied by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 2 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of ^{100~5000c / dm 2, 100~2000c / dm} 2, and more preferably selected from the range of 200~1000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of hydrochloric acid in the electrolytic solution is preferably 0.1 to 5% by mass.

After the surface is roughened by the electrochemical surface roughening method, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum scraps on the surface. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  The mechanical surface roughening method and the electrochemical surface roughening method may each be used alone for roughing, or the mechanical surface roughening method followed by the electrochemical surface roughening method. You may roughen.

Following the roughening treatment, anodizing treatment is preferably performed. There is no restriction | limiting in particular in the method of the anodizing process which can be used in this invention, A well-known method can be used. By performing the anodizing treatment, an oxide film is formed on the aluminum substrate. For the anodizing treatment, a method of electrolyzing an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% as an electrolytic solution at a current density of 1 to 10 A / dm ² is preferably used. A method of electrolysis at a high current density in sulfuric acid described in Japanese Patent No. 1,412,768, a method of electrolysis using phosphoric acid described in US Pat. No. 3,511,661, chromium Examples thereof include a method using a solution containing one or more acids, oxalic acid, malonic acid and the like. The formed anodic oxidation coating amount is suitably 1 to 50 mg / dm ² , preferably 10 to 40 mg / dm ² . The anodized coating amount is obtained by, for example, immersing an aluminum plate in a chromic phosphate solution (85% phosphoric acid solution: 35 ml, prepared by dissolving 20 g of chromium (IV) oxide in 1 L of water) to dissolve the oxide film, It is obtained from mass change measurement before and after dissolution of the coating on the plate.

  The anodized aluminum base material may be subjected to sealing treatment as necessary. These sealing treatments can be performed using known methods such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.

  Further, after these treatments, as a hydrophilization treatment, a water-soluble resin such as polyvinylphosphonic acid, a polymer or copolymer having a sulfonic acid group in the side chain, polyacrylic acid, a water-soluble metal salt ( For example, zinc borate) or a primer coated with a yellow dye, an amine salt or the like is also suitable.

  Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A No. 5-304358 is covalently used.

(Coating of heat sensitive layer)
In the present invention, the heat-sensitive layer is usually formed by dissolving each of the above components in a solvent and applying the solution on the hydrophilic layer. Solvents used here include 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, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, it is not limited to this. These solvents are used alone or in combination. The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass. The coating, the coating amount of the hydrophilic layer obtained after drying (solid content) may be varied depending on the use, in the range of ^{0.1g / m 2 ~10g / m 2} , preferably 0.5 g / m ² ~ The range is 5 g / m ² . If the amount is too small, the printing durability is lowered. Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

(Plate making method)
The lithographic printing plate of the present invention can be exposed using a laser light source. Available laser light sources include semiconductor lasers, LEDs, helium neon lasers, YAG lasers, carbon dioxide lasers, and the like.

  The laser-exposed lithographic printing plate material is directly attached to a cylinder of a printing machine. The lithographic printing plate material is supplied with dampening water and printing ink via a roller of the printing press, and is developed by peeling off the image forming layer portion not irradiated with laser with dampening water / printing ink. .

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.
Example 1
<< Manufacture of support (hydrophilic support) >>
The molten metal of JIS A1050 alloy containing 99.5 mass% or more of aluminum and Fe 0.30 mass%, Si 0.10 mass%, Ti 0.02 mass%, and Cu 0.013 mass% was subjected to cleaning treatment and cast. In the cleaning process, a degassing process was performed to remove unnecessary gases such as hydrogen in the molten metal, and a ceramic tube filter process was performed. The casting method was a DC casting method. The solidified 500 mm thick ingot was chamfered 10 mm from the surface and homogenized at 550 ° C. for 10 hours so as not to coarsen the intermetallic compound. Next, after hot rolling at 400 ° C. and intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, cold rolling was performed to obtain an aluminum rolled plate having a plate pressure of 0.30 mm. By controlling the roughness of the rolling roll, the centerline average surface roughness Ra after cold rolling was controlled to 0.2 μm. Then, it applied to the tension leveler in order to improve planarity.

Next, a surface treatment was carried out to make a lithographic printing plate material support. First, in order to remove the rolling oil on the surface of the aluminum plate, degreasing treatment was carried out with a 10% by mass sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were carried out with a 30% by mass sulfuric acid aqueous solution at 50 ° C. for 30 seconds. Next, in order to improve the adhesion between the support and the heat-sensitive layer and to provide water retention to the non-image area, a so-called graining treatment was performed to roughen the surface of the support. An aqueous solution containing 1% by mass of nitric acid and 0.5% by mass of aluminum nitrate is kept at 45 ° C., and an aluminum web is allowed to flow in the aqueous solution, while an indirect power feeding cell has a current density of 20 A / dm ² and a duty ratio of 1: 1. Electrolytic graining was performed by applying an anode side electric quantity of 240 C / dm ² in an alternating waveform. Thereafter, etching treatment was carried out with a 10% by mass sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were carried out with a 30% by mass sulfuric acid aqueous solution at 50 ° C. for 30 seconds. Furthermore, in order to improve wear resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. An anodization of 2.5 g / m ² by using a 20% by weight sulfuric acid aqueous solution as an electrolyte at 35 ° C. and carrying out an aluminum web through the electrolyte and performing an electrolytic treatment at a direct current of 14 A / dm ² by an indirect power supply cell. A film was prepared. Thereafter, a silicate treatment was performed to ensure hydrophilicity as a non-image portion of the printing plate. The treatment was carried in such a way that a No. 3 sodium silicate 1.5 mass% aqueous solution was kept at 70 ° C. so that the contact time of the aluminum web was 15 seconds, and further washed with water. The adhesion amount of Si was 10 mg / m ² . The center line surface roughness Ra of the support produced as described above was 0.25 μm.

<< Production of Image Forming Layer and Production of Planographic Printing Plate Materials 1-6 >>
On the support obtained by the above method, the following image forming layer coating solutions 1 to 6 are coated with a wire bar, dried in an oven at 70 ° C. for 60 seconds, and the dry coating amount of the image forming layer is 1.0 g. / M ² of lithographic printing plate materials 1 to 67 were prepared. In addition, the viscosity of the water-soluble resin in the table was measured as follows. First, the solid content was adjusted to 10% by mass and measured with a B-type viscometer at 25 ° C.

  In addition, the aqueous dispersion (solid content 20 mass%) of the microcapsule A used in Table 1 was prepared as follows.

(Preparation of aqueous dispersion of microcapsule A (solid content: 20% by mass))
As an oil phase component, 4.5 g of vinyloxy compound (the following structure), an adduct of trimethylolpropane and xylylene diisocyanate (Takenate D-110N, microcapsule wall material manufactured by Mitsui Takeda Chemical Co., Ltd.), Millionate MR- 200 (Japan polyurethane aromatic isocyanate oligomer, microcapsule wall material) 3.75 g, infrared absorbing dye A (following structure) 1.5 g, Pionine A41C (Takemoto Yushi Co., Ltd. anionic surfactant) 0.1 g Dissolved in 18.4 g of ethyl acetate. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA205 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) was prepared. Using a homogenizer (Excel Auto Homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd.), the oil phase component and the aqueous phase component were stirred and emulsified for 30 minutes at a rotational speed of 10,000 rpm. Thereafter, a solution obtained by dissolving 0.38 g of tetraethylenepentamine (pentafunctional amine, microcapsule wall cross-linking agent) in 26 g of water was added, followed by stirring at 65 ° C. for 3 minutes while cooling with water. The obtained microcapsule dispersion was filtered with a 5 μm filter cloth, and water was added to adjust the solid content to 20% by mass to prepare an aqueous dispersion of microcapsule A (solid content 20% by mass). . The obtained microcapsules A had an average particle size of 0.07 μm.

The lithographic printing plate materials 1 to 6 thus obtained were subjected to an image including a flat screen step chart at a plate surface energy of 200 mJ / cm ^{2 using} a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser. After exposure under the conditions of 2400 dpi (dpi represents the number of dots per 2.54), it is attached to a cylinder of a printing machine DAIYA1F manufactured by Mitsubishi Heavy Industries, Ltd. without developing, and fountain solution {ASTROMARK 3 ( 2% by weight aqueous solution} manufactured by Nikken Chemical Laboratory Co., Ltd., followed by ink {High Unity Red MZ (manufactured by Toyo Ink Manufacturing Co., Ltd.)} and paper {OK Topcoat Plus 104.7 g / m ² (Made by Nippon Paper Industries Co., Ltd.)} was supplied for printing.

<Evaluation of printability>
The following (a) to (c) are evaluated, and the results are shown in Table 2.

(A) On-machine developability The reflection density at the non-image portion of the printed material is measured from the printing and the number of sheets required until the numerical value becomes 0.09 or less is defined as the on-machine developability. The smaller this value, the better the on-press developability.

(B) Printing durability Printing was performed at a printing speed of 12,000 sheets / hour by changing the printing paper to high-quality paper Kimari SW127.97 g / m ² . The number of sheets until unevenness occurs in a 50% flat screen image of printed matter is defined as the strength of printing durability. The larger this value, the better the printing durability.

(C) Blanket stain The reflection density of the blanket corresponding to the non-image area of the printed material after 10,000 sheets of printing was measured. The smaller this value, the better the stain resistance.

From Table 2, it can be seen that when the viscosity of the water-soluble resin is 50 to 1000 × 10 ⁻³ Pa · s, excellent printing durability and excellent on-press developability and blanket contamination are obtained.

  According to the present invention, a lithographic printing plate material excellent in on-press developability, printing durability and stain resistance and a plate making method thereof are provided by appropriately selecting the viscosity of the water-soluble resin used in the image forming layer. it can.

Claims (2)

A lithographic printing plate material having, on a hydrophilic support, an image forming layer containing at least one selected from heat-meltable particles and microcapsules and a water-soluble resin, wherein the water-soluble resin is 25 ° C A lithographic printing plate material, wherein the 10% by mass aqueous solution is from 50 × 10 ⁻³ Pa · s to 1000 × 10 ⁻³ Pa · s. A method for producing a lithographic printing plate, comprising developing the lithographic printing plate material according to claim 1 by supplying dampening water and ink on a cylinder of a printing press.