JP2006247856A - Aluminum plate support for photosensitive lithographic printing plate material, method for manufacturing aluminum plate support and photosensitive lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate material with excellent printout properties, resistance to plate wear and smear proofness during printing, and an aluminum plate support for a photosensitive lithographic printing plate material and its manufacturing method. <P>SOLUTION: The method for manufacturing the aluminum plate support for a photosensitive lithographic printing plate material features the procedures to roughen/anodize the surface of the support, then make it hydrophilic, treat it with silicate of soda, and treat it with an aqueous solution containing a polyvinyl phosphonic acid. Finally, the method dries the aluminum plate support at 150 to 230°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive lithographic printing plate material, an aluminum plate support used therefor, and a method for producing the same.

  2. Description of the Related Art In recent years, CTP (computer to plate) systems that record digital image data directly on a printing plate material with a laser light source have become widespread in the technology for producing printing plates for offset printing.

  In addition, as a printing plate material used in these CTP systems, a printing plate that can be applied to a conventional printing machine without requiring a developing treatment with a processing solution containing a special agent (for example, alkali, acid, solvent, etc.). For example, a phase change type printing plate material that does not require development processing at all, a printing plate material that is processed with water or a substantially neutral processing liquid mainly composed of water, on a printing press There are known printing plate materials called chemical-free type printing plate materials and processless type printing plate materials, such as printing plate materials that are developed at an initial stage of printing and do not require a development step.

  As these processless type printing plate materials, on-press development type printing plate materials that remove non-image portions of the image forming layer on a printing machine are known, and image exposure has been performed using these printing plate materials. A plate making method is known in which dampening water and printing ink are supplied from a dampening water supply roller and printing ink supply roller of a printing machine to the printing plate material, and development is performed on the printing machine (for example, Patent Document 1, 2).

  Further, as the on-press development type printing plate material, for example, as disclosed in Japanese Patent No. 2938397 and Japanese Patent No. 2938398, thermoplastic fine particles and water-soluble binder on the hydrophilic layer or aluminum grain. A printing plate material provided with a heat-sensitive image forming layer containing a photothermal conversion material, or a printing plate material in which a photothermal conversion material is contained in a hydrophilic layer and an image is formed by the heat generated by the photothermal conversion material is known ( For example, see Patent Document 3.)

  Among these, in the field of printing that requires a relatively high printing durability, it is known to use a printing plate material having an aluminum plate as a support and an image recording layer thereon.

  As the aluminum plate, a surface subjected to roughening treatment and anodizing treatment is generally used. However, there are problems such as damage to small spots or stains when performing a large amount of printing. there were. For the purpose of improving these problems, for example, as a printing plate material using an aluminum plate support described in JP-A-2000-255177, the surface of the aluminum grain support has a specific average height made of boehmite. A printing plate material is known in which protrusions are formed and a polymerizable photosensitive layer is provided thereon.

  Further, a printing plate material using an aluminum support that has been subjected to a specific roughening treatment, anodized, and then hydrophilized with polyvinylphosphonic acid (see, for example, Patent Document 4), an aluminum support, and A printing plate material (see, for example, Patent Document 5) in which an intermediate layer containing polyvinylphosphonic acid is provided between photosensitive layers is known.

However, a method of developing an exposed printing plate material on a printing press using these on-press development type printing plate materials does not require a special wet development process, and a high-definition image can be obtained. However, there are cases in which stains may occur after contact with the dampening water supply roller of the printing plate, there are cases where the number of waste paper used before printing is printed out, and the printing durability is insufficient. there were.
JP 9-211182 A JP 2002-219881 A JP 2003-231374 A JP 2002-103834 A JP 2003-57831 A

  An object of the present invention is to provide a photosensitive lithographic printing plate material which is excellent in printability, printing durability, and anti-staining property during printing, and an aluminum plate support for the photosensitive lithographic printing plate material and the production thereof. Is to provide a method.

  The object of the present invention is achieved by the following constitution.

(Claim 1)
A photosensitive lithographic printing plate comprising a roughening treatment and an anodizing treatment, followed by a sodium silicate treatment as a hydrophilic treatment, a treatment with an aqueous solution containing polyvinylphosphonic acid, and then drying at 150 to 230 ° C. A method for producing an aluminum plate support for materials.

(Claim 2)
An aluminum plate support for a photosensitive lithographic printing plate material produced by the method for producing an aluminum plate support for a photosensitive lithographic printing plate material according to claim 1.

(Claim 3)
A photosensitive lithographic printing plate material comprising an image forming layer on the aluminum plate support for the photosensitive lithographic printing plate material according to claim 2.

(Claim 4)
The photosensitive lithographic printing plate material according to claim 3, wherein the image forming layer is a heat-sensitive image forming layer.

  A photosensitive lithographic printing plate material having excellent printing performance, printing durability, and anti-staining property during printing, and an aluminum plate support for the photosensitive lithographic printing plate material therefor, and a method for producing the same Can be provided.

  Hereinafter, the present invention will be described in detail.

  The feature of the present invention is that the aluminum plate support for a photosensitive lithographic printing plate material (also simply referred to as an aluminum plate support) is subjected to a surface roughening treatment and anodizing treatment, and a sodium silicate treatment as a hydrophilic treatment. The treatment is carried out with an aqueous solution containing polyvinylphosphonic acid, followed by a post-treatment of drying at a high temperature of 150 to 230 ° C. That is, it is characterized by a combination of sodium silicate treatment, polyvinylphosphonic acid treatment, and high-temperature drying treatment at 150 to 230 ° C. As a result, the polyvinylphosphonic acid is fused to the aluminum plate, and the adhesion with the image forming layer is improved. In addition, the number of non-image areas that can be removed during on-press development increases with sodium silicate treatment alone, and contamination becomes worse.

(Aluminum plate support and surface treatment)
The aluminum plate support of the present invention is a pure aluminum plate or an aluminum alloy plate. Various aluminum alloys can be used, for example, alloys of aluminum such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, etc., and various rolling methods. The aluminum plate manufactured by can be used. In addition, recycled aluminum plates obtained by rolling recycled aluminum ingots such as scrap materials and recycled materials that are becoming popular in recent years can also be used.

  Prior to roughening (graining treatment), the aluminum plate support of the present invention is preferably subjected to a degreasing treatment in order to remove rolling oil on the surface. As the degreasing treatment, a degreasing treatment using a solvent such as trichrene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. An alkaline aqueous solution such as caustic soda can also 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 support. In this case, the substrate is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof and desmutted. It is preferable to perform the treatment.

  Next, a roughening process is performed. Examples of the roughening method include a mechanical method and a method of etching by electrolysis. In the present invention, AC electrolytic surface roughening treatment in an electrolytic solution mainly composed of hydrochloric acid is preferable, but mechanical surface roughening treatment and electrolytic surface roughening treatment mainly composed of nitric acid may be performed prior to this.

The mechanical roughening method 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 a bristle having a diameter of 0.2 to 0.8 mm, and for example, volcanic ash particles having a particle size of 10 to 100 μm on water. While supplying the uniformly dispersed slurry, 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 pressure from a nozzle, and causing the surface to collide obliquely with the support surface. Can do. Further, for example, a sheet coated with abrasive particles having a particle diameter of 10 to 100 μm on the support surface so as to exist 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 transferring the rough surface pattern of the sheet by applying the pressure together.

After roughening by the above mechanical roughening method, it is preferable to immerse in an aqueous solution of acid or alkali in order to remove the abrasive, the formed aluminum scraps, etc. that have digged into the surface of the support. 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 surface preferably 0.5 to 5 g / m ^2. 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.

The electrolytic surface-roughening treatment mainly composed of nitric acid 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 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 surface 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, aluminum ions, and the like can be added to the electrolytic solution.

After the electrolytic surface-roughening treatment mainly composed of nitric acid, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum hydroxide and the like 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 amount of aluminum dissolved on the surface is preferably 0.5 to ² g / m ² . Further, it is preferable to carry out a neutralization treatment by immersing in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof after immersing with an alkaline aqueous solution.

In the AC electrolytic surface roughening treatment in an electrolytic solution mainly composed of hydrochloric acid, the hydrochloric acid concentration is 5 to 20 g / l, preferably 6 to 15 g / l. The current density is 15 to 120 A / dm ² , preferably 20 to 90 A / dm ² . The quantity of electricity was 400~2000C / dm ^2, preferably 500~1200C / dm ^2. The frequency is preferably in the range of 40 to 150 Hz. The temperature of the electrolytic solution can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, aluminum ions, and the like can be added to the electrolytic solution.

After the electrolytic surface roughening treatment is performed in the electrolytic solution mainly containing hydrochloric acid, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum hydroxide and the like 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 amount of aluminum dissolved on the surface is preferably 0.5 to ² g / m2. Further, 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.

  The arithmetic average roughness (Ra) of the surface of the obtained aluminum support on the image forming layer side is preferably 0.4 to 0.7 μm, and is controlled by a combination of hydrochloric acid concentration, current density and electric quantity in the roughening treatment. be able to.

Following the roughening treatment, an anodizing treatment is performed to form an anodized film. The anodizing method according to the present invention is preferably carried out using sulfuric acid or an electrolytic solution mainly composed of sulfuric acid as the electrolytic solution. The concentration of sulfuric acid is preferably 5 to 50% by mass, particularly preferably 10 to 35% by mass. The temperature is preferably 10 to 50 ° C. The treatment voltage is preferably 18V or more, and more preferably 20V or more. Current density is preferably 1~30A / dm ^2. Quantity of electricity is preferably from 200~600C / dm ^2.

The amount of the anodized coating formed is preferably 1 to 6 g / m ² , more preferably ² to 3 g / m ² . The anodic oxidation coating amount is obtained by, for example, immersing an aluminum plate in a phosphoric acid chromic acid solution (manufactured by dissolving 85% phosphoric acid solution: 35 ml, chromic anhydride: 20 g in 1 L of water), dissolving the oxide film, It is calculated | required from the mass change measurement etc. before and after melt | dissolution of the coating. Micropores are generated in the anodized film, and the density of the micropores is preferably 400 to 700 / μm ^{2, and} more preferably 400 to 600 / μm ² .

  The anodized support is subjected to sodium silicate treatment, followed by polyvinylphosphonic acid treatment, and then dried at 150 to 230 ° C. The sodium silicate treatment is, for example, immersion treatment at 50 to 90 ° C. for 10 to 60 seconds with JIS No. 3 sodium silicate 1 to 2%. This treatment can impart hydrophilicity to the surface. Next, the sodium silicate remaining in the micropores of the anodized film is washed out with water or hot water.

  Processing with the aqueous solution containing the polyvinyl phosphonic acid which concerns on this invention after that is making the said anodized surface of the aluminum plate support body contact the aqueous solution containing polyvinyl phosphonic acid.

  The polyvinyl phosphonic acid according to the present invention is a vinyl polymer having a phosphonic group, preferably having a number average molecular weight of 5,000 to 40,000, particularly preferably 10,000 to 25,000. As content of the said polyvinylphosphonic acid, it is preferable to exist in 0.05-0.6 mass% with respect to aqueous solution. Furthermore, it is still more preferable to use in the range of 0.1-0.4 mass%.

  Examples of the treatment with an aqueous solution containing polyvinylphosphonic acid include, but are not limited to, a coating method, a spray method, a dip method, and the like. As this treatment, a dip type is suitable for making the equipment inexpensive. In the case of a dip type, it is preferable to treat with a 0.1 to 0.4 mass% aqueous solution of polyvinylphosphonic acid. The treatment temperature is preferably 20 to 90 ° C. and the treatment time is preferably 10 to 180 seconds.

  After the aqueous solution containing polyvinylphosphonic acid is brought into contact with the support, squeeze treatment or water washing treatment may be performed in order to remove excessively laminated polyvinylphosphonic acid.

  After these treatments, drying is performed at 150 to 230 ° C. Drying at 150 to 230 ° C. means that the temperature of the support surface is within this range. The surface temperature can be measured with a commercially available non-contact surface thermometer. The drying time is preferably 10 to 100 seconds, particularly preferably 20 to 50 seconds. The heating method for drying may be drying using hot air, or using a quartz heater or a far infrared heater.

  Although it is conceivable to carry out the polyvinyl phosphonic acid treatment without carrying out the sodium silicate treatment, the polyvinyl phosphonic acid dissolves as printing is repeated after the on-press development, which often causes stains. The sodium silicate treatment is essential in the present invention because this contamination can be suppressed.

(Image forming layer that can be developed on-machine)
The on-press developable image forming layer according to the present invention is a dampening solution or a dampening solution and a printing ink at the time when the image forming layer is subjected to a printing process after image exposure, without passing through a development process. Thus, the image forming layer that is a non-image part at the time of printing is removed, and an image forming layer that can form a printable image can be formed, and the effect of the present invention is particularly large in the case of a thermal image forming layer. .

  The heat-sensitive image forming layer is a layer capable of forming an image by image exposure, and is a heat-sensitive image forming layer capable of forming an image by heat generation of a layer containing a photothermal conversion material that converts image exposure light into heat. The layer containing the photothermal conversion material may be the image forming layer according to the present invention, or may be a hydrophilic layer or another layer adjacent to the heat sensitive image forming layer.

  As the heat-sensitive image forming layer, a so-called negative image forming layer in which the image forming layer in the exposed portion is changed in a direction to be fixed on the hydrophilic layer by heat is preferably used.

  Examples of the image forming layer in which the exposed portion is changed in a direction to be fixed on the hydrophilic layer by heat include, for example, a hydrophilic layer before exposure and from a hydrophilic layer to a hydrophobic layer by heat. And an image forming layer containing a hydrophobized precursor that can be changed. Examples of the hydrophobizing precursor include thermoplastic hydrophobic particles such as heat-melting particles or heat-fusible particles, microcapsules enclosing a hydrophobic substance, blocked isocyanate compounds, such as hydrophilicity (water-soluble or water-soluble by heat). Polymers that change from (swellable) to hydrophobic, specifically, for example, polymers containing aryl diazosulfonate units disclosed in JP-A-2000-56449. Examples of the thermoplastic hydrophobic particles include heat-fusible particles and heat-fusible particles described later.

  The heat-meltable particles are particles made of a material that has a low viscosity when melted, and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink landing sensitivity is lowered.

  Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, peroxide groups and the like. Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide and the like can be added. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used.

  Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed.

  Further, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches or the like is improved.

  The hot-melt particles are preferably dispersible in water, and the average particle diameter is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle diameter is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible particles is applied on the porous hydrophilic layer described later, the heat-fusible particles become pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause scumming. When the average particle size of the heat-meltable particles is larger than 10 μm, the resolution is lowered.

  Moreover, the composition of the inside and the surface layer of the heat-meltable particle may be continuously changed, or may be coated with a different material. As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used. As content of the heat-meltable particle | grains in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is still more preferable.

  The heat-fusible particles include thermoplastic hydrophobic polymer particles, and there is no specific upper limit for the softening temperature of the polymer particles, but the temperature should be lower than the decomposition temperature of the polymer particles. preferable. The weight average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.

  Specific examples of the polymer that constitutes the polymer particles include, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene, and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- ( (N-methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl such as polymer Ester (co) polymer, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof. Of these, (meth) acrylic acid esters, (meth) acrylic acid (co) polymers, vinyl ester (co) polymers, polystyrene, and synthetic rubbers are preferably used.

  The heat-fusible particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 10 μm from the viewpoint of on-press developability and sensitivity. 3 μm. Further, the composition of the heat fusible particles may vary continuously between the inside and the surface layer, or may be coated with a different material. As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used. As content of the thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is still more preferable.

  Examples of the microcapsule include microcapsules enclosing a hydrophobic material described in JP-A Nos. 2002-2135 and 2002-19317. The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and still more preferably 0.5 to 3 μm.

[Blocked isocyanate compound]
The blocked isocyanate compound is obtained by reacting an isocyanate compound with a blocking agent described below. The blocked isocyanate compound that can be used in the image forming layer is preferably an aqueous dispersion of a compound as described later. Good on-press developability can be obtained by coating and forming from an aqueous dispersion.

[Isocyanate compound]
As the isocyanate compound, aromatic polyisocyanate [diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), polyphenylpolymethylene polyisocyanate (crude MDI), naphthalene diisocyanate (NDI), etc.]; aliphatic polyisocyanate [1,6 -Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), etc.]; Alicyclic polyisocyanate [isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, etc.]; [Xylylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), etc.]; , Isocyanurate groups, carbodiimide groups, oxazolidine group-containing modified compounds, etc.); and the urethane prepolymer and the like with these polyisocyanates with terminal isocyanate groups consisting of active hydrogen-containing compound having a molecular weight of 50 to 5,000. Further, polyisocyanate compounds described in JP-A-10-72520 can also be preferably used. Of the above, tolylene diisocyanate is particularly preferred because of its fast reactivity.

[Blocking agent]
A well-known thing can be used as a blocking agent of an isocyanate group. For example, alcohol blocking agents such as methanol and ethanol, phenol blocking agents such as phenol and cresol, formaldoxime, acetoaldoxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, cyclohexanone oxime, acetoxime, diacetyl monooxime, benzophenone oxime, etc. Oxime blocking agents, acid amid blocking agents such as acetanilide, ε-caprolactam, γ-butyrolactam, active methylene blocking agents such as dimethyl malonate and methyl acetoacetate, mercaptan blocking agents such as butyl mercaptan, succinic acid imide Imide blocking agents such as maleic imide, imidazole blocking agents such as imidazole and 2-methylimidazole, ureas such as urea and thiourea Examples include blocking agents, carbamic acid blocking agents such as phenyl N-phenylcarbamate, amine blocking agents such as diphenylamine and aniline, and imine blocking agents such as ethyleneimine and polyethyleneimine. Among these, it is particularly preferable to use an oxime blocking agent.

  The content of the blocking agent is preferably such that the active hydrogen group in the blocking agent is 1.0 to 1.1 equivalents relative to the isocyanate group of the isocyanate compound. When used in combination with an additive having a hydrogen group, the active hydrogen group, which is the sum of the blocking agent and other additives having an active hydrogen group, is contained in an amount of 1.0 to 1.1 equivalents relative to the isocyanate group. It is preferable to make it. If it is less than 1.0, unreacted isocyanate groups remain, and if it exceeds 1.1, the blocking agent and the like are excessive, which is not preferable.

  The dissociation temperature of the blocking agent is preferably 80 to 200 ° C, more preferably 80 to 160 ° C, and particularly preferably 80 to 130 ° C.

[Polyol]
The blocked isocyanate compound is preferably a polyol adduct obtained by further adding a polyol. By containing a polyol, the storage stability of the blocked isocyanate compound can be improved. Further, the image strength when heated to form an image is improved, and the printing durability is improved.

  Examples of the polyol include ethylene glycol, propylene glycol, triethylene glycol, glycerin, trimethylol methane, trimethylol propane, pentaerythritol, neopentyl glycol, 1,6-hexylene glycol, butanediol, hexamethylene glycol, xylylene glycol, Polyhydric alcohols such as sorbitol and sucrose, polyether polyols obtained by addition polymerization of these polyhydric alcohols or polyamines with ethylene oxide or propylene oxide, or both, polytetramethylene ether polyols, polycarbonate polyols, poly Caprolactone polyols and the above polyhydric alcohols, for example, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, seba A vinyl monomer is grafted onto polyester polyols, polybutadiene polyols, acrylic polyols, castor oil, polyether polyols or polyester polyols obtained by reacting with polybasic acids such as acid, fumaric acid, maleic acid and azelaic acid. And polymer polyols and epoxy-modified polyols obtained by the above method.

  Among these, ethylene glycol, propylene glycol, triethylene glycol, glycerin, trimethylol methane, trimethylol propane, pentaerythritol, neopentyl glycol, 1,6-hexylene glycol, butanediol, hexamethylene glycol, xylylene glycol Polyol having a molecular weight of 50 to 5,000 such as sorbitol can be preferably used, and a low molecular weight polyol having a molecular weight of about 50 to 500 can be particularly preferably used.

  The preferred content of the polyol is in such a range that the hydroxyl group in the polyol is 0.1 to 0.9 equivalent to the isocyanate group of the isocyanate compound. In this range, the storage stability of the blocked isocyanate compound is particularly good. improves.

[Blocking method]
As a method for blocking an isocyanate compound, for example, the isocyanate compound is heated to about 40 to 120 ° C. in an inert gas atmosphere under anhydrous conditions, and a predetermined amount of the blocking agent is dropped and mixed while stirring, followed by stirring. There is a method of reacting over several hours while continuing. At this time, any solvent can be used. Moreover, a well-known catalyst, for example, an organometallic catalyst, a tertiary amine, a metal salt catalyst, etc. can also be used.

  Examples of the organometallic catalyst include stannous catalysts such as stannous octoate, dibutyltin diacetate, and dibutyltin dilaurate, and lead-based catalysts such as lead 2-ethylhexanoate. Examples of the tertiary amine include triethylamine. N, N-dimethylcyclohexylamine, triethylenediamine, N, N′-dimethylpiperazine, diazabicyclo [2.2.2] -octane, etc., as the metal salt catalyst, for example, cobalt naphthenate, calcium naphthenate, naphthene Examples include lead acid lithium oxide. The usage-amount of these catalysts is 0.001-2 mass parts normally with respect to 100 mass parts of polyisocyanate compositions, Preferably it is 0.01-1 mass part.

  In the case where the blocked isocyanate compound is also a compound with a polyol, the blocking agent and the polyol are reacted with the isocyanate compound. After the isocyanate compound and the polyol are reacted first, the remaining isocyanate group and the blocking agent are reacted with each other. Alternatively, after the isocyanate compound and the blocking agent are reacted first, the remaining isocyanate group and the polyol may be reacted.

  The average molecular weight of the blocked isocyanate compound is preferably 500 to 2,000, more preferably 600 to 1,000 in terms of weight average molecular weight. Within this range, the balance between reactivity and storage stability becomes good.

[Production of water dispersion]
The blocked isocyanate compound obtained as described above can be made into an aqueous dispersion by, for example, adding a surfactant and water, and vigorously mixing and stirring using a homogenizer or the like.

  Examples of surfactants include anionic surfactants such as sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium dodecyl diphenyl ether disulfonate, sodium succinate dialkyl ester sulfonate, polyoxyethylene alkyl ester, polyoxyethylene alkyl aryl, and the like. Nonionic surfactants such as ether, or alkylbetaine type salts such as lauryl betaine and stearyl betaine salts, both amino acid types such as lauryl-β-alanine, lauryl di (aminoethyl) glycine, and octyldi (aminoethyl) glycine Surfactant etc. can be mentioned. These can be used alone or in combination of two or more. Of these, nonionic surfactants are preferred.

  The solid content of the blocked isocyanate compound aqueous dispersion is preferably 10 to 80% by mass. As addition amount of surfactant, it is preferable that it is 0.01-20 mass% in solid content of an aqueous dispersion. When an organic solvent is used for the blocking reaction of the isocyanate compound, the organic solvent can be removed after forming an aqueous dispersion.

  The image forming layer may contain a water-soluble material, and examples of the water-soluble material include the following materials.

[Water-soluble polymer compound]
Examples of the water-soluble material contained in the image forming layer include known water-soluble polymer compounds that dissolve in an aqueous solution having a pH of 4 to 10.

  Specific examples include resins such as polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, polyacrylic acid, polyacrylate, polyacrylamide, and polyvinylpyrrolidone. Of these, polysaccharides, polyacrylic acid, polyacrylates, polyacrylamide, and polyvinylpyrrolidone are preferable.

  As polysaccharides, starches, celluloses, polyuronic acids, pullulan, chitosan, or derivatives thereof can be used, and cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and carboxymethyl cellulose. The sodium salt and ammonium salt are more preferable. The polyacrylic acid, polyacrylate, and polyacrylamide preferably have a molecular weight of 3,000 to 1,000,000, and more preferably 5,000 to 500,000.

  Of these, polyacrylates such as sodium polyacrylate are most preferred. The polyacrylate is highly effective as a hydrophilic treatment agent for the hydrophilic layer, and can improve the hydrophilicity of the surface of the hydrophilic layer that appears when the image forming layer is developed on the machine.

[oligosaccharide]
As a water-soluble material, an oligosaccharide can be contained in addition to the water-soluble polymer compound described above. Examples of the oligosaccharide include raffinose, trehalose, maltose, galactose, sucrose, and lactose, and trehalose is particularly preferable.

[Other materials that can be contained in the image forming layer]
The image forming layer can contain an infrared absorbing dye as a photothermal conversion material. As the content of the infrared absorbing dye, it is necessary to consider the balance with the printing press contamination during on-press development depending on the degree of coloring of the dye with visible light. as, 0.001 g / m ² or more, preferably less than 0.2 g / m ^2, more preferably less than 0.05 g / m ^2. Needless to say, it is preferable to use a dye that is less colored with visible light.

  The image forming layer can contain a surfactant. Si-based or F-based surfactants can be used, but it is particularly preferable to use a surfactant containing Si element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass, based on the entire hydrophilic layer (solid content as the coating solution).

(Photothermal conversion material)
The photosensitive lithographic printing plate material of the present invention preferably has a layer containing a photothermal conversion material as described above, and examples of the photothermal conversion material include those described below. The layer containing the photothermal conversion material may be an image forming layer, or may be a hydrophilic layer or a layer adjacent to the image forming layer. Examples of the photothermal conversion material include infrared absorbing dyes or pigments.

(Infrared absorbing dye)
Examples of infrared absorbing dyes include organic compounds such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, and naphthalocyanine dyes. , Azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. Specifically, JP-A-63-139191, JP-A-1-33547, 1-160683, 1-280750, 1-293342, 2-2074, 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, 2004-345257, 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.

  Any metal can be used as long as it is a fine particle having a particle size of 0.5 μm or less, preferably 100 nm or less, and 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. 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 further improved. It becomes good. 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. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste). An average primary particle size of less than 0.01 is not preferable because dispersion becomes difficult. A dispersing agent can be appropriately used for the dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles. Although the kind of dispersing agent is not specifically limited, it is preferable to use Si type surfactant containing Si element.

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.

  The addition amount of these photothermal conversion materials is 0.1 to 50% by mass, preferably 1 to 30% by mass, and more preferably 3 to 25% by mass with respect to the layer containing the material.

  Examples of light sources for image exposure include lasers, light emitting diodes, xenon lamps, xenon flash lamps, halogen lamps, carbon arc lamps, metal halide lamps, tungsten lamps, high pressure mercury lamps, and electrodeless light sources. When using an array-type light source such as a light-emitting diode array, or when controlling exposure of a light source such as a halogen lamp, metal halide lamp, or tungsten lamp with an optical shutter material such as liquid crystal or PLZT, digital Exposure is possible and preferable. In this case, direct writing can be performed without using a mask material.

  Laser exposure is suitable for direct writing without using a mask material because light exposure can be performed in the form of a beam in accordance with image data. When a laser is used as a light source, it is easy to reduce the exposure area to a very small size, and high-resolution image formation is possible.

  Laser scanning methods include cylindrical outer surface scanning, cylindrical inner surface scanning, and planar scanning. In cylindrical outer surface scanning, laser exposure is performed while rotating a drum around which the recording material is wound, and the rotation of the drum is used as main scanning, and the movement of laser light is used as sub scanning. In cylindrical inner surface scanning, a recording material is fixed to the inner surface of a drum, a laser beam is irradiated from the inside, and a main scanning is performed in the circumferential direction by rotating part or all of the optical system. Is linearly moved parallel to the axis of the drum to perform sub-scanning in the axial direction. In plane scanning, a laser beam main scan is performed by combining a polygon mirror, a galvanometer mirror, and an fθ lens, and a sub-scan is performed by moving a recording medium. Cylindrical outer surface scanning and cylindrical inner surface scanning are easier to increase the accuracy of the optical system and are suitable for high-density recording.

  In the case where development processing is required, a method of developing the photosensitive lithographic printing plate material using an automatic processor is an embodiment.

  Printing can be performed using a general lithographic printing machine. In recent years, the printing industry has been screaming for environmental protection, and in printing inks, inks that do not use petroleum-based volatile organic compounds (VOC) have been developed and are becoming popular. This is particularly noticeable when the printing inks are used. Environmentally friendly printing inks include soybean oil ink “Naturalis 100” manufactured by Dainippon Ink & Chemicals, Inc., VOC zero ink “TK Hi-Echo NV” manufactured by Toyo Ink, and process ink “Soyselbo” manufactured by Tokyo Ink. Can be mentioned.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the examples, “parts” represents “parts by mass” unless otherwise specified.

[Preparation of substrate]
(Preparation of substrate 1)
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm was immersed in a 5% by mass aqueous sodium hydroxide solution at 50 ° C., dissolved so that the dissolved amount became 2 g / m ² , and washed with water. Then, it was immersed in a 10% by mass aqueous nitric acid solution at 25 ° C. for 30 seconds, neutralized and then washed with water. Next, this aluminum plate was subjected to an electrolytic surface roughening treatment with an electrolytic solution containing hydrochloric acid 10 g / L and aluminum 0.5 g / L using a sinusoidal alternating current at a current density of 60 A / dm ² .

The distance between the electrode and the sample surface at this time was 10 mm. The electrolytic surface-roughening treatment was performed in 12 steps, and the amount of electricity processed at one time (when anode) was 80 C / dm ^2, and the amount of electricity treated was 960 C / dm ² (when anode). Further, a pause time of 1 second was provided between each surface roughening treatment.

After electrolytic surface roughening, the surface is immersed in a 10% by mass phosphoric acid aqueous solution maintained at 50 ° C. and etched so that the amount of dissolution including the smut of the roughened surface becomes 1.2 g / m ² , and washed with water. did. Next, anodization was performed in a 20% sulfuric acid aqueous solution so that the amount of electricity was 250 C / dm ² under a constant voltage condition of 20 V, followed by washing with water. Next, after squeezing the surface water after washing with water, it was immersed in a 2% by weight No. 3 sodium silicate aqueous solution maintained at 85 ° C. for 30 seconds, washed with water, and then washed with 0.4% by weight polyvinyl phosphonic acid at 60 ° C. It was immersed for 30 seconds and washed with water. The surface was squeezed and immediately heat treated at 180 ° C. for 50 seconds to obtain a substrate 1.

  The average roughness of the substrate 1 was 0.55 μm as measured using SE1700α (Kosaka Laboratory Ltd.).

  Substrates 2 to 8 were produced by changing the sodium silicate treatment, polyvinylphosphonic acid treatment and heat treatment conditions after the anodizing treatment of the substrate 1 as shown in Table 1.

[Preparation of photosensitive printing plate material]
(Printing plate material 1)
The following image forming layer coating solution was applied onto the aluminum substrate obtained in the above production example using a wire bar and dried at 55 ° C. for 3 minutes. The dry weight of the image forming layer was 0.6 g / m ² . Subsequently, the printing plate material 1 was produced by performing the aging process for 24 hours at 45 degreeC.

Hydrophobized precursor: thermoplastic fine particles (acrylonitrile / styrene / alkyl acrylate / methacrylic acid copolymer, emulsion: iodosol GD87B, manufactured by NSC Japan, average particle size 90 nm, Tg 60 ° C., solid content 45 mass%) 00
Water-soluble resin (sodium polyacrylate, Aqualic DL522, manufactured by Nippon Shokubai Co., Ltd., solid content: 30% by mass) 1.67
Infrared absorbing dye (ADS830WS, manufactured by American Dye Source, 1 mass% aqueous solution) 50.00
Pure water 28.33
The solid content concentration (% by mass) of the image forming layer coating solution was 10.0%.

(Printing plate material 2)
The following heat-sensitive layer coating solution containing a microcapsule solution was bar-coated on the aluminum substrate obtained in the above production example, and then dried in an oven at 100 ° C. for 60 seconds. A printing plate material 2 of m ² was produced.

35.4 g of water
Microcapsule liquid 9.0g
0.24 g of acid precursor
Synthesis of microcapsule solution As oil phase components, 4.5 g of bis (vinyloxyethyl) ether of bisphenol A, an adduct of trimethylolpropane and xylylene diisocyanate (Takenate D-110N manufactured by Mitsui Takeda Chemical Co., Ltd., micro Capsule wall material) 5 g, Millionate MR-200 (Nippon Polyurethane Co., Ltd. aromatic isocyanate oligomer, microcapsule wall material) 3.75 g, infrared absorbing dye 1.5 g, Pionine A41C (Takemoto Yushi Co., Ltd. surfactant) 0.1 g was dissolved in 18.4 g of ethyl acetate. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA205 (Kuraray polyvinyl alcohol) was prepared. The oil phase component and the aqueous phase component were emulsified at 12000 rpm for 10 minutes using a homogenizer. 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, and the mixture was stirred for 30 minutes while being cooled with water, and further at 65 ° C. for 3 hours. The microcapsule solution thus obtained had a solid content concentration of 24% by mass and an average particle size of 0.3 μm.

  Printing plate materials of Examples 1 to 6 and Comparative Examples 1 and 2 described in Table 2 were prepared by combining the base material of Table 1 and the printing plate materials 1 and 2 described above.

[Exposure and printing of photosensitive printing plate materials]
The printing plate material was wound around and fixed to an external exposure drum with the image forming layer facing outside. A laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm is used for exposure, and the exposure energy is 400 mJ / cm ² for the printing plate material 1 and 2400 dpi (dpi represents the number of dots per inch, that is, 2.54 cm). An image was formed with 175 lines.

  The exposed image was a non-image portion having a width of 2 cm on the lower side, a solid band having a width of 2 cm on the non-image portion, and a halftone dot image having a whole surface of 50%.

  As a printing machine, DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd. was used. There were a total of five rollers in contact with the plate cylinder, watering roller: 1 and ink roller: 4, and the arrangement was as shown in FIG. In FIG. 1, roller A is a watering roller, rollers B, C, D, and E are ink rollers, and A, B, C, and A are applied to the printing plate material mounted on the plate cylinder 1 when the plate cylinder 1 rotates. Touch in order of D and E. The appropriate nip width of each roller is as shown below.

Roller A: 5mm
Roller B: 4mm
Roller C: 4mm
Roller D: 4mm
Roller E: 3mm
Prior to printing, the relationship between the nip width of each roller and the rotation angle of the adjusting screw was examined.

[Evaluation]
For printing evaluation, coated paper, fountain solution: 2% by mass of Astro Mark 3 (manufactured by Nikken Chemical Laboratories) and ink (manufactured by Toyo Ink Co., Ltd., Toyo King High Unity M Red) were used. The fountain solution supply amount and the ink supply amount were set to be the same as those for PS plate printing (standard setting). The sequence of printing and printing is printed at the timing when the plate cylinder is rotated, the watering roller is brought into contact with the plate cylinder and then rotated three times, and then the ink roller is brought into contact (simultaneously four) and rotated three times. The sequence was such that paper was sent, cylinderd and printed.

  Printing evaluation was performed by attaching an exposed plate to the plate cylinder. The results are shown in Table 2.

(On-machine developability-printability)
Up to 1 to 200 printed materials were observed after printing, and printing performance was evaluated. The number of printed sheets in which a non-image area was not stained, a solid density was 1.5 or more, and no halftone dot image was 50% was measured and used as an index for on-press developability.
.

(Print stains)
The number of sheets in which the non-image area was easily stained during printing was obtained.

(Print life)
175 LPI (LPI represents the number of lines per inch, that is, 2.54 cm), and the point at which the 5% dot was reduced to 3% was evaluated as the end point.

  From the results in Table 2, it can be seen that the photosensitive lithographic printing plate material of the present invention is excellent in all of printing performance, printing stain, and printing durability.

It is a partial schematic diagram of the printing machine used in the examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plate cylinder 2 Exposed lithographic printing plate material A Dampening water supply roller B Ink supply roller C Ink supply roller D Ink supply roller E Ink supply roller

Claims (4)

A photosensitive lithographic printing plate comprising a roughening treatment and an anodizing treatment, followed by a sodium silicate treatment as a hydrophilic treatment, a treatment with an aqueous solution containing polyvinylphosphonic acid, and then drying at 150 to 230 ° C. A method for producing an aluminum plate support for materials. An aluminum plate support for a photosensitive lithographic printing plate material produced by the method for producing an aluminum plate support for a photosensitive lithographic printing plate material according to claim 1. A photosensitive lithographic printing plate material comprising an image forming layer on the aluminum plate support for the photosensitive lithographic printing plate material according to claim 2. The photosensitive lithographic printing plate material according to claim 3, wherein the image forming layer is a heat-sensitive image forming layer.

Images