JP2011079279A - Support for lithographic printing plate and lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support for a lithographic printing plate which is excellent in an inking property without deteriorating printing durability and anti-scumming property, and to provide a lithographic printing plate material which has aptitude to laser drawing, enables chemical-free developing, and is excellent in inking property. <P>SOLUTION: In the support for a lithographic printing plate, an intermediate layer located between a plastic film substrate and a hydrophilic layer contains a polymer latex, a gelatin and a crosslinking agent, wherein the amount of the polymer latex is 10-100 mass% based on the amount of the gelatin. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate support having a hydrophilic layer on a plastic film substrate. The present invention also relates to a lithographic printing plate material using such a lithographic printing plate support.

  As a lithographic printing plate support, an aluminum plate having a roughened surface such as a PS plate and having an anodized film is widely used. On the other hand, a lithographic printing plate material using a paper or film as a support. Is widely used. One example of such a lithographic printing plate material is a lithographic printing plate material that utilizes silver salt diffusion transfer development (DTR development). In this lithographic printing plate material, exposed silver halide crystals are chemically developed by DTR development to form black silver to form hydrophilic non-image areas, while unexposed silver halide crystals are contained in a developer. The silver salt complexing agent becomes a silver salt complex and diffuses to the physical development nuclei on the surface, causing physical development to form an image area mainly composed of ink-accepting physical development silver. A lithographic printing plate material using a flexible substrate such as a plastic film is cheaper and easier to handle than an aluminum support, and in particular, a plate making system using a CTP (computer to plate) system. Is preferably used because it can be accommodated in an exposure apparatus very compactly as a roll-shaped lithographic printing plate material.

  An example of providing a hydrophilic layer on the surface of a plastic film substrate without using an aluminum support is, for example, a hydrophilic resin layer made of a (meth) acrylate-based polymer having a hydroxyalkyl group described in JP-B-49-2286. A hydrophilic layer composed of a urea resin and a pigment described in JP-B-56-2938, a hydrophilic layer obtained by curing an acrylamide polymer described in JP-A-48-83902 with aldehydes, A hydrophilic layer obtained by curing a composition containing a water-soluble melamine resin, polyvinyl alcohol and water-insoluble inorganic powder described in JP-A-62-280766, side described in JP-A-8-184967 A hydrophilic layer obtained by curing a water-soluble polymer containing a repeating unit having an amidino group in the chain, and JP-A-8-27208 A hydrophilic layer containing a hydrophilic (co) polymer described in Japanese Patent Publication No. H11, and cured with a hydrolyzed tetraalkyl orthosilicate, a hydrophilic layer having an onium group described in JP-A-10-296895, A hydrophilic layer obtained by three-dimensionally cross-linking a crosslinked hydrophilic polymer having a Lewis base moiety described in JP-A No. 11-311861 by interaction with a polyvalent metal ion, described in JP-A No. 2000-122269 Examples thereof include a hydrophilic layer containing a hydrophilic resin and a water-dispersible filler.

  Furthermore, JP 2000-158839 A (Patent Document 1) discloses that a hydrophilic layer containing a water-soluble polymer having a carboxyl group such as polyacrylic acid is formed on a film support, resulting in good ink detachability. Is shown. However, these conventionally known lithographic printing plate materials using a hydrophilic layer are not sufficiently satisfactory in the printing durability of the image area and the ground stain resistance of the non-image area, and the lithographic printing plate which improves this problem As a material, the present applicant disclosed in Japanese Patent Application No. 2009-70880 a lithographic printing plate material in which an intermediate layer containing gelatin and a crosslinking agent is provided between a support and hydrophilicity. However, when this intermediate layer is used, there is a case in which the ink inking property is lowered.

  On the other hand, as described above, there is a demand for a printing plate having a flexible support such as a plastic film. However, a lithographic printing plate using a silver salt diffusion transfer method (DTR method) uses a highly alkaline solution as a developer. Therefore, development processing is complicated, liquid property management of the processing solution is troublesome, and there is a problem in maintaining stable quality. Against this background, there is a strong demand for processless printing plates that do not require development processing, or printing plates that are capable of chemical-free development processing in which the developer does not substantially contain an alkali agent. There are great expectations for chemical-free printing plates.

  Up to now, as processless printing plates, those using an ink jet method or a thermal transfer method, and methods using an ablation method, a heat fusion type, and a microcapsule type using a laser beam Can be mentioned. Although these methods have a problem that the image quality is inferior to the method using laser light described below, these methods are preferable because a lithographic printing plate can be most easily produced. On the other hand, as a method using a laser beam, as for an ablation method, for example, JP-A-8-507727, JP-A-6-186750, JP-A-6-199064, JP-A-7-314934, Examples thereof include those described in Kaihei 10-58636 and JP-A-10-244773. Examples of the heat fusion type include heat described in Japanese Patent No. 2938397, Japanese Patent Application Laid-Open No. 2001-88458, Japanese Patent Application Laid-Open No. 2001-39047, Japanese Patent Application Laid-Open No. 2004-50616, Japanese Patent Application Laid-Open No. 2004-237592, and the like. And those utilizing a method of fusing the heat-fusible fine particles. With respect to the microcapsule type, light is applied to the microcapsules or fine particles as seen in JP2002-29162A, JP2002-46361A, JP2002-137562A, JP2004-66482A, and the like. This is a type in which a material having a polymerizable function is used and these are cured by photopolymerization. However, even in the case of a lithographic printing plate using these various methods, there is a common problem that when the support having the intermediate layer and the hydrophilic layer described above is used on a plastic film substrate, the ink deposition property is not sufficient. It was.

  JP 2003-215801 A (Patent Document 2), JP 2008-230205 A (Patent Document 3), JP 2008-238505 A (Patent Document 4), JP 2008-250198 A (Patent Document 5). ) Is a photopolymerization type lithographic printing plate material capable of chemical-free development, and a lithographic printing having a photosensitive layer using an anionic copolymer having a vinyl group bonded to the side chain via a phenyl group A plate material is disclosed. However, the copolymer copolymer that enables such chemical-free development is more hydrophilic than the alkali-soluble polymer used in the conventionally known alkali development type lithographic printing plate. For this reason, when a support having an intermediate layer and a hydrophilic layer on a plastic film substrate is used as a support for a lithographic printing plate material capable of such chemical-free development, there is a problem that ink inking property is lowered. Was particularly prominent and improvement was sought. Further, when a copolymer having a phenyl group with a vinyl group substituted on the side chain and a sulfonic acid group was used as the copolymer, the decrease in ink adhesion was particularly remarkable.

  JP-A-2005-305852 (Patent Document 6) discloses that a gelatin and a specific amount of gelatin are contained in an undercoat layer located between a plastic film substrate and a hydrophilic layer for the purpose of improving coating failure and on-press developability. A lithographic printing plate provided with an undercoat layer containing a hardener is described. However, sufficient ink fillability was not obtained. Japanese Patent Application Laid-Open No. 2005-161863 (Patent Document 7) and Japanese Patent Application Laid-Open No. 2006-56185 (Patent Document 8) disclose a first undercoat layer containing a polymer latex on a plastic film substrate and a second layer containing gelatin. A support for a lithographic printing plate having an undercoat layer and a hydrophilic layer has been disclosed, but sufficient ink deposition properties were not obtained.

JP 2000-158839 A JP 2003-215801 A JP 2008-230205 A JP 2008-238505 A JP 2008-250198 A JP 2005-305852 A JP 2005-161863 A JP 2006-56185 A

  An object of the present invention is to provide a support for a lithographic printing plate that is excellent in ink adherence without deterioration in printing durability and background stain resistance during printing. Another object of the present invention is to provide a lithographic printing plate material that has suitability for laser drawing, can be developed chemically, and has excellent ink deposition properties.

The above object of the present invention has been achieved by the following invention.
(1) A lithographic printing plate support containing a hydrophilic layer on a plastic film substrate, wherein an intermediate layer located between the plastic film substrate and the hydrophilic layer is a polymer latex, gelatin and a crosslinking agent A support for a lithographic printing plate, wherein the amount of the polymer latex is from 10 to 100% by mass based on the amount of gelatin.
(2) On the hydrophilic layer of the lithographic printing plate support described in (1) above, a copolymer having a phenyl group and a sulfonic acid group substituted with a vinyl group in the side chain, a photopolymerization initiator, and an increase A lithographic printing plate material having a photosensitive layer containing a dye-sensitive material.

  According to the present invention, it is possible to provide a lithographic printing plate support having excellent ink depositing properties without deteriorating the printing durability and background stain resistance during printing. Further, it is possible to provide a lithographic printing plate material that is capable of chemical-free development and excellent in ink deposition properties.

  As the plastic film substrate that the lithographic printing plate support of the present invention has, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, Typical examples include cellulose nitrate, and polyethylene terephthalate and polyethylene naphthalate are particularly preferably used.

  The lithographic printing plate support of the present invention has a hydrophilic layer on a plastic film substrate, and an intermediate layer located between the plastic film substrate and the hydrophilic layer comprises a polymer latex, gelatin and a crosslinking agent. And the amount of the polymer latex is 10 to 100% by mass with respect to the amount of gelatin. In the Japanese Patent Application No. 2009-70880, the applicant of the present application is a lithographic printing plate material capable of obtaining sufficient performance for both the printing durability of the image area and the soil resistance of the non-image area, and between the plastic film substrate and the hydrophilic layer. Filed a lithographic printing plate material having an intermediate layer containing gelatin. However, when a hydrophilic layer or a photosensitive layer is coated on an intermediate layer containing gelatin, there are cases where sufficient ink depositing properties cannot be obtained. Therefore, as a result of intensive studies, the present inventor has found that sufficient ink setting properties can be obtained by setting the amount of polymer latex to 10 to 100% by mass with respect to the amount of gelatin. In other words, the excellent effect of the present invention described above is that the amount of polymer latex contained in the intermediate layer is within the above range, so that diffusion and transfer of low molecular components of gelatin when a hydrophilic layer or photosensitive layer is applied on the intermediate layer. Is not expected to reach the photosensitive layer, and it is presumed that sufficient ink deposition properties can be obtained.

  The amount of polymer latex contained in the intermediate layer of the present invention is 10 to 100% by mass with respect to the amount of gelatin, but a more preferable amount of polymer latex is 30 to 50% by mass with respect to the amount of gelatin. When the amount of the polymer latex is less than 10% by mass, sufficient ink depositability cannot be obtained. This is presumed to be because the low molecular component of gelatin causes diffusion transfer of low molecular components of gelatin. Further, even if the amount of the polymer latex exceeds 100% by mass, sufficient ink depositability cannot be obtained. This is presumed that even when the amount of the polymer latex is large, the intermolecular interaction of gelatin in the intermediate layer is lowered, and diffusion transfer of low molecular components of gelatin occurs.

  As the polymer latex used in the intermediate layer in the present invention, various known latexes such as a homopolymer and a copolymer can be used. Homopolymers include vinyl acetate, vinyl chloride, styrene, methyl acrylate, methyl methacrylate, butyl acrylate, methacrylonitrile, butadiene, isoprene, acrylonitrile, etc., and copolymers include ethylene butadiene, styrene butadiene, acrylonitrile, Butadiene, styrene / p-methoxystyrene, styrene / vinyl acetate, vinyl acetate / vinyl chloride, vinyl acetate / diethyl maleate, methyl methacrylate / acrylonitrile, methyl methacrylate / butadiene, methyl methacrylate / styrene, methyl methacrylate / vinyl acetate, methyl methacrylate・ Vinylidene chloride, methyl acrylate / acrylonitrile, methyl acrylate / butadiene, methyl acrylate / styrene, methyl Acrylate-vinyl acetate, acrylic acid-butyl arylate, methyl acrylate-vinyl chloride, butyl acrylate-styrene and the like. Among these, an anionic polymer latex is preferable, and a polymer latex having a carboxyl group is preferably used. Examples of the polymer latex containing a carboxyl group include carboxyl-modified styrene / butadiene latex, carboxyl-modified acrylonitrile / butadiene latex, and carboxyl-modified methyl methacrylate / butadiene.

  Since the intermediate layer of the present invention contains gelatin, the polymer latex is preferably an emulsion dispersed in an aqueous medium, and the average particle diameter is preferably 0.01 to 1.0 μm, more preferably. 0.05 to 0.2 μm. This emulsion may be obtained by dispersing a polymer latex in an aqueous medium as it is, but an emulsion produced by emulsion polymerization is particularly desirable.

  A preferred range for the solids coverage of the intermediate layer of the present invention is between 1 g and 50 g per square meter, a more preferred range is between 2 g and 25 g per square meter, and the most preferred range is from 3 g per square meter. Between 15 g. If the coating amount of the solid content of the intermediate layer is small, the ground stain resistance of the non-image area may deteriorate or the printing durability of the image area may deteriorate. In addition, if the solid layer coating amount of the intermediate layer is excessive, the printing durability of the image area may be deteriorated.

  The gelatin contained in the intermediate layer of the present invention preferably has an average molecular weight of 30,000 or more, more preferably 70,000 to 150,000. Examples include alkaline gelatin from cow bone or cow skin, acidic gelatin using pork skin, and modified gelatin (eg, phthalated gelatin). Impurities contained in these gelatins (eg, calcium ions, Examples thereof include gelatin in which salts such as sodium ions and chloride ions, lipids, nucleic acids and degradation products thereof, aldehydes, and the like are reduced by purification or desalting treatment. Two or more kinds of gelatins may be used in combination in the intermediate layer of the present invention.

  The intermediate layer of the present invention contains a crosslinking agent. Examples of the crosslinking agent include various known compounds. Specific examples include epoxy compounds, aziridine compounds, oxazoline compounds, isocyanate compounds and derivatives thereof, aldehyde compounds such as formalin, methylol compounds, hydrazide compounds, and the like. Particularly preferred crosslinking agents are epoxy compounds.

  As the epoxy compound, a compound having two or more epoxy groups in the molecule is preferably used. Specific examples of preferred epoxy compounds are shown below.

  Specific examples of preferable compounds as the aziridine compound are shown below.

  As the oxazoline compound, a compound containing two or more groups represented by the following general formula (1) as a substituent in the molecule is preferable, and various commercially available compounds are provided, for example, from Nippon Shokubai Co., Ltd. under the trade name Epocross. Various grades of compounds are preferably used.

  As the isocyanate compound, a compound that is stable in water is preferable, and a so-called self-emulsifiable isocyanate compound or a blocked isocyanate compound is preferably used. Examples of self-emulsifying isocyanate compounds include Japanese Patent Publication No. 55-7472 (US Pat. No. 3,996,154) and Japanese Patent Laid-Open No. 5-222150 (US Pat. No. 5,252,696). Self-emulsifiable isocyanate as described in JP-A-9-71720, JP-A-9-328654, JP-A-10-60073, and the like.

  Examples of aldehyde compounds and methylol compounds such as formaldehyde and glyoxal include formaldehyde, glyoxal, and various N-methylol compounds as shown below.

  Specific examples of compounds that can be preferably used as the hydrazide compound are shown below.

  There is a preferred range for the ratio of various crosslinking agents and gelatin as described above. The crosslinking agent is preferably used in the range of 1 to 40 parts by mass with respect to 100 parts by mass of gelatin.

  Further, the intermediate layer of the present invention in which the amount of polymer latex is 10 to 100% by mass with respect to the amount of gelatin may be an intermediate layer having a gelatin dissolution rate of 0 to 10% by mass by containing the crosslinking agent. Preferably, it is 0 to 5% by mass.

The dissolution rate of the gelatin of the present invention was determined by finely cutting a support having an intermediate layer coated on a plastic film substrate, preparing a total of 100 cm ^{2 of} this piece, and placing it in 10 ° C. pure water at 25 ° C. The mixture was stirred for 1 minute with SHAKING BATHS manufactured by Nippon Genetics Co., Ltd., and this liquid was collected. The amount of gelatin dissolved in the liquid was quantified using an ultraviolet / visible absorption spectrum measuring apparatus (V-560 manufactured by UShiO). Is required.

  The intermediate layer of the lithographic printing plate material of the present invention can contain inorganic fine particles. Examples of these inorganic fine particles include colloidal silica, titanium dioxide particles, alumina particles (for example, aluminum oxide hydrate, aluminum hydroxide), zeolite, and other metal oxide particles. These inorganic fine particles may be subjected to a surface treatment on the particle surface.

  The constitution of the hydrophilic layer of the present invention preferably contains a water-soluble polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group and an acetoacetoxy group, inorganic fine particles and a crosslinking agent.

  Examples of the water-soluble polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group, and an acetoacetoxy group contained in the hydrophilic layer of the lithographic printing plate support of the present invention include, for example, polyvinyl alcohol, hydroxy Water-soluble polymers having a hydroxyl group such as ethyl cellulose and hydroxypropyl cellulose, water-soluble polymers having a carboxyl group such as polyacrylic acid, polystyrene-maleic acid copolymer, polyvinyl acetate-crotonic acid copolymer, carboxymethyl cellulose, and Examples thereof include water-soluble polymers having an amino group such as polyethyleneimine and polyallylamine.

  The hydrophilic layer of the present invention particularly preferably contains a polymer represented by the general formula (2), and by using the polymer, a lithographic printing plate particularly excellent in printing durability and ink landing property of an image area. A material is obtained.

  In the formula, X represents mass% of repeating units in the polymer composition, and represents an arbitrary numerical value from 1 to 40. The repeating unit A represents a repeating unit having a group selected from a carboxyl group, an amino group, a hydroxyl group, and an acetoacetoxy group as a reactive group, and the repeating unit B has a hydrophilic group necessary for making the polymer water-soluble. Represents a unit.

  It is important that the water-soluble polymer represented by the general formula (2) contains a reactive group in the molecule for allowing a crosslinking reaction to proceed efficiently with a crosslinking agent described later. Such reactive groups include carboxyl groups, amino groups, hydroxyl groups, and acetoacetoxy groups. In order to obtain a water-soluble polymer having such a reactive group in the molecule, it is preferable to incorporate various monomers having a reactive group in a copolymerized form. As monomers corresponding to the repeating unit A represented by the general formula (2), acrylic acid, methacrylic acid, 2-carboxylethyl acrylate, 2-carboxylethyl methacrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid , Maleic acid monoalkyl ester, fumaric acid monoalkyl ester, 4-carboxylstyrene, carboxyl-containing monomers such as acrylamide-N-glycolic acid and their salts, allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylamino Ethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylamide, 4-amino Amino group-containing monomers such as tylene, 4-aminomethylstyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-vinylbenzyl) amine, 4-vinylpyridine , Nitrogen-containing heterocycle-containing monomers such as 2-vinylpyridine and N-vinylimidazole, (meth) acrylamides such as N-methylolacrylamide and 4-hydroxyphenylacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2 -Hydroxypropyl (meth) acrylates such as hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and glycerol monomethacrylate, and acetoacetoxy methacrylate, and the like, are not limited thereto.

  In the above general formula (2), X, which is the ratio of the repeating unit A in the copolymer, is 1 to 40, and if it is less than this range, sufficient film strength may not be obtained even if the crosslinking reaction proceeds. If it is more than this range, the effect of introducing the repeating unit B for imparting water solubility described below is lessened, and the affinity of the hydrophilic layer for water may be lowered.

  Furthermore, as a monomer for giving the repeating unit B in the general formula (2), vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, 2- Sulfonic acid group-containing monomers such as acrylamido-2-methylpropanesulfonic acid and their salts, Phosphoric acid group-containing monomers such as vinylphosphonic acid and their salts, dimethyl diallyl ammonium chloride, acrylic acid-2- (trimethylammonio) Ethyl ester, methacrylic acid-2- (trimethylammonio) ethyl ester, acrylic acid-2- (triethylammonio) ethyl ester, methacrylic acid-2- (triethylammonio) ethyl ester, (3-acrylamidopropyl) trime Quaternary ammonium salts such as ruammonium chloride, N, N, N-trimethyl-N- (4-vinylbenzyl) ammonium chloride, acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N (Meth) acrylamides such as N, diethylacrylamide, N-isopropylmethacrylamide, methacrylic acid methoxydiethylene glycol monoester, methacrylic acid methoxypolyethylene glycol monoester, methacrylic acid polypropylene glycol monoester , N-vinyl pyrrolidone, N-vinyl caprolactam and the like, but are not limited thereto. These water-soluble monomers may be used alone to constitute the repeating unit B, or any two or more of them may be used. Specific examples of preferable water-soluble polymers in the present invention are shown below. In the present invention, water-soluble means that 0.5 g or more of a water-soluble polymer is dissolved in 1 L of water.

  Examples of the inorganic fine particles preferably used for the hydrophilic layer in the present invention include colloidal silica, titanium dioxide particles, alumina particles (for example, aluminum oxide hydrate, aluminum hydroxide), zeolite, particles made of other metal oxides, and the like. It is done. These inorganic fine particles may be subjected to a surface treatment on the particle surface. Particularly preferred inorganic fine particles in the present invention are colloidal silica and titanium dioxide particles, and particularly excellent ink deposition properties are obtained.

  The colloidal silica preferably used in the present invention is a spherical shape, needle shape, irregular shape, or a necklace shape in which spherical particles are continuous, preferably having an average particle diameter measured by a light scattering system particle size distribution meter of 5 to 200 nm. Silica sols having various shapes and particle diameters and stably dispersed in water are preferably used. As such materials, various colloidal silicas are provided, for example, under the name of Snowtex from Nissan Chemical Industries, Ltd., and as a spherical silica sol, Snowtex XS (particle diameter 4 to 6 nm), Snowtex S (particle diameter 8) To 11 nm), Snowtex 20 (particle size 10 to 20 nm), Snowtex XL (particle size 40 to 60 nm), Snowtex YL (particle size 50 to 80 nm), Snowtex ZL (particle size 70 to 100 nm), Snowtex As an acidic type silica sol from which MP-2040 (particle diameter: 200 nm) and sodium salt on the surface have been removed, Snowtex OXS, OS and the like can be preferably used. Examples of the needle-like or amorphous silica sol include Snowtex UP, OUP and Fine Cataloid F-120 available from JGC Catalysts and Chemicals. Examples of the necklace-shaped silica sol include Snowtex PS-S (particle diameter 80 to 120 nm), PS-M (particle diameter 80 to 150 nm), and PS-SO and PS-MO which are acidic types thereof.

  The titanium dioxide particles preferably used in the present invention are preferably spherical particles having an average particle diameter of 10 to 800 nm, and the production method includes a chlorine method and a sulfuric acid method, such as anatase type, rutile type and bulcalite type. However, preferably, rutile type titanium dioxide is surface-treated with an inorganic substance. Inorganic treatment on the surface of titanium dioxide includes alumina treatment, silica treatment, zirconia treatment, zinc treatment, tin treatment, antimony treatment, and the like, and each oxide is used. Among these, silica treatment, zirconia treatment, and zinc treatment are preferable, and silica treatment and zirconia treatment are particularly preferable. These inorganic treatments may be composite treatments, and examples include composite treatment of silica and alumina, composite treatment of zirconia and alumina, and composite treatment of silica, zirconia and alumina. Such titanium dioxide particles are, for example, from Sakai Chemical Industry Co., Ltd. R-11P (particle diameter 200 nm), R-21 (particle diameter 200 nm), R-61N (particle diameter 260 nm), R-5N (particle diameter 250 nm). ), R-45M (particle diameter 290 nm), A-110 (particle diameter 150 nm), A-190 (particle diameter 150 nm), from Ishihara Sangyo Co., Ltd. TTO-55A (particle diameter 30-50 nm), TTO-55D ( The particle diameter is 30-50 nm).

  As the inorganic fine particles contained in the hydrophilic layer, each kind of inorganic fine particles may be used alone, or different kinds of inorganic fine particles may be mixed and used in various proportions. The content of the inorganic fine particles as described above is preferably in the range of 0.1 to 10 parts by mass, particularly preferably in the range of 0.5 to 5 parts by mass with respect to 1 part by mass of the water-soluble polymer described above. is there.

  There is a preferred range for the dry weight of the hydrophilic layer, specifically, the dry weight of the hydrophilic layer is between 0.1 g and 10 g per square meter, and the preferred range is 0.2 g to 5 g per square meter. The most preferred range is between 0.3 g and 2 g per square meter.

  The hydrophilic layer of the present invention preferably contains a crosslinking agent, and the same group of compounds as the crosslinking agent that can be contained in the intermediate layer described above can be used. Particularly preferred crosslinking agents are epoxy compounds.

  The hydrophilic layer of the present invention can contain a surfactant, a pH adjuster and the like in addition to the water-soluble polymer, inorganic fine particles, and crosslinking agent described above.

  An image can be formed on the lithographic printing plate support of the present invention by the following known methods, but the present invention is not limited to these methods.

  An ink receptive image layer is formed by depositing an ink receptive material on the hydrophilic layer in an image form by a known ink jet method. The ink receiving material is a water-resistant material, and may be a thermosetting material or a photocurable material that is cured by heat or light after hot melt or image formation.

  Examples of thermosetting materials include halogenated bisphenol, resorcin, bisphenol F, tetrahydroxyphenyl ethane, novolac, polyhydroxy compound, polyglycol, glycerin triether, polyolefin, epoxidized soybean oil, vinylcyclohexene dioxide, epoxidation Combinations of soybean oil with organic acids or anhydrides (eg, phthalic acid, maleic acid, sebacic acid or anhydride), or organic peroxides (eg, benzoyl peroxide or phthaloid peroxide), diallyl orthophthalate, Diallyl isophthalate or diallyl chlorate, or a combination thereof with an organic oxide (eg, benzoyl peroxide or phthaloid peroxide), N-methyl-N'-methyloluron ethyl ether, N-methyl-N -Methyloluron methyl ether, N-ethyl-N'-methyloluron methyl ether, tetramethylolurea, N-methyl-N, N ', N'-trimethylolurea, N-ethyl-N, N', N'- Trimethylol urea, N, N'-diethyl-N, N'-dimethylol urea, mono and polymethylol melamine, p-methylol phenol, phenol, o-methylol phenol, 2,4-dimethylol phenol or 2,6- Mention may be made of combinations of dimethylolphenol and formaldehyde, aniline resins, xylene resins, unsaturated polyester resins, and furan resins.

  Examples of photo-curing substances include unsaturated polyesters (examples of dibasic acids: maleic anhydride, fumaric acid, itaconic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydro anhydride Phthalic acid, isophthalic acid, terephthalic acid, trimellitic anhydride and pyromellitic anhydride; examples of polyhydric alcohols: ethylene glycol, propylene glycol, 2,3-butanediol, 1,3-butanediol, neopentyl glycol, 1 , 4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, glycerol trimethylolpropane, polyethylene glycol, polypropylene glycol); and acrylate or methacrylate monomers or oligomers (eg, methoxy) Ethylene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypolyethylene glycol methacrylate, 2-hydroxydodecyl methacrylate, 2-hydroxydodecyl acrylate, triethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol methacrylate, Polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene Glycol dimethacrylate, 2,2-bis (4-methacryloxydiethoxyphenyl) propane, diethylene glycol diacrylate, polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol Diacrylate, polypropylene glycol diacrylate, 2,2'-bis (4-acryloxypropyoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylol Ethanetrimethacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, trimethylolmethane triacrylate, trimethylol group And ropandiacrylate monococonut oil fatty acid ester, tetramethylol methane tetraacrylate, dibromoneopentyl glycol dimethacrylate, and 2,3-dibromopropyl acrylate). The photocurable material is generally used with a photopolymerization initiator. Examples of the photopolymerization initiator include aromatic ketones such as benzophenone, acetophenones, diketones, and acyloxime esters.

  Formation of the oleophilic image layer by the thermal transfer method can be performed, for example, as follows. The heat-sensitive transfer layer of a heat-sensitive transfer sheet comprising a heat-sensitive transfer layer provided on a substrate is adhered to the hydrophilic layer surface of the lithographic printing plate support of the present invention. Next, the substrate is heated imagewise by a thermal head, and the thermal transfer layer corresponding to the heated portion is transferred onto the hydrophilic layer. Thereby, an oleophilic layer comprising a heat-sensitive transfer layer is formed on a part of the surface of the hydrophilic layer. Of course, a laser beam can be used instead of the thermal head. As the material of the heat-sensitive transfer layer of the heat-sensitive transfer sheet, a material that can be melted by heating and transferred to the image receiving layer is used. The heat-sensitive transfer layer is composed of a resin and an inorganic pigment that are melted by heating, and a dye is added as necessary. Examples of the resin include paraffin wax, natural rosin, higher fatty acid ester, polyamide, ethylene / vinyl acetate copolymer, polyester, acrylic resin such as polyacrylic acid ester, polyvinyl chloride, etc. Examples of inorganic pigments Examples thereof include silica, calcium carbonate, carbon black, titanium white and the like.

  Also, a known photopolymerizable photosensitive layer is coated on the hydrophilic layer, and after exposure, the unexposed part is developed with a chemical-free developer, or removed with a moistening liquid on the printing press. It is also preferable to form an image layer. As the polymer used in such a photosensitive layer, there is a polymer having a polymerizable double bond in the molecule, and a system using a polymer having a polymerizable double bond in the side chain as a polymer having a polymerizable double bond in the molecule. Is preferred. As a system that provides a photo-curable photosensitive layer that can be developed with a chemical-free developing solution according to the present invention or removed with a dampening solution or the like on a printing machine to form an image layer, A monomer having a phenyl group substituted with a vinyl group as a monomer having a bond, and a monomer having a sulfonic acid group in the structure as a water-soluble group-containing monomer (for example, 3-sulfopropyl methacrylate, 4-sulfostyrene, 4- A copolymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonic acid group, which contains a sulfo-n-butylmethacrylamide, sulfo-tert-butylacrylamide, etc.) as a copolymerization component. Is a salt (eg sodium salt, potassium salt, triethylammonium salt, lithium salt, tetramethylammonium salt) ) May be in the form. This polymer has a sulfonic acid group in the structure to enhance water solubility, so that the developer has a pH value in the range of 4.0 or more and less than 10.0, and is a chemical-free developer substantially free of an alkali agent. A method of developing with a printer (hereinafter also referred to simply as water development), or a method of developing on a printing machine by mounting an exposed plate after exposure on a printing machine (hereinafter referred to as on-machine development) Is also possible. Further, by having a phenyl group having a vinyl group substituted on the side chain as a polymerizable double bond, high sensitivity can be achieved.

  The phenyl group substituted with a vinyl group in the side chain of the copolymer is a vinyl group substituted on an aromatic ring such as a benzene ring or a naphthalene ring, and the vinyl group is a halogen atom, a carboxyl group, or a sulfo group. , A nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group and the like, and the aromatic ring may have a substituent. Since such a polymer is firmly bonded to the hydrophilic layer of the lithographic printing plate support of the present invention, image peeling or dissolution due to physical stress during printing is extremely unlikely and thus improved. Ink fillability is preferable because it can be maintained until completion even in long run printing over a large number of copies. The phenyl group substituted with a vinyl group is specifically represented by the following general formula (3).

In the formula, R ₁₁ , R ₁₂ and R ₁₃ may be the same or different, and each is a hydrogen atom, halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. A group selected from a group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group The alkyl group and aryl group constituting these groups are a halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, hydroxy group, alkoxy group , Aryloxy group, alkylthio group, arylthio group, al It may be substituted with a killamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group or the like. Among these groups, those in which R ₁₁ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (for example, a methyl group, an ethyl group, etc.) and R ₁₂ and R ₁₃ are hydrogen atoms are particularly preferable.

In the formula, R ₁₄ represents a hydrogen atom, a halogen atom, a carboxyl group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, A group selected from an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group. The alkyl group and aryl group constituting these groups are halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group. , An alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group and the like.

In the formula, m ₁ represents an integer of 0 to 4, and p ₁ represents an integer of 0 or 1. L ₁ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom or a polyvalent linking group comprising a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom group.

Examples of the heterocyclic ring constituting L ₁ include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thia Triazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline A nitrogen-containing heterocycle such as a ring and a quinoxaline ring, a furan ring, a thiophene ring, and the like, and these heterocycles may have a substituent.

  When the polyvalent linking group described above has a substituent, examples of the substituent include a halogen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkenyl group, and an alkynyl group. Group, hydroxy group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group and the like.

  Specific examples of the copolymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonic acid group in the present invention are shown below.

  The photopolymerizable photosensitive layer of the lithographic printing plate material of the present invention is suitable for laser drawing, and after exposure, the unexposed portion is developed with a chemical-free developer. Alternatively, for the purpose of forming an image layer by removing with a dampening liquid or the like on a printing machine, a photopolymerization initiator and a copolymer having a phenyl group and a sulfonic acid group substituted with a vinyl group in the side chain, and A photosensitive layer containing a sensitizing dye is extremely preferable. As a photoinitiator used for this invention, arbitrary compounds can be used if it is a compound which can generate | occur | produce a radical by irradiation of light or an electron beam.

  Examples of the photopolymerization initiator that can be used in the present invention include organic boron salt compounds, aromatic onium salt compounds, organic peroxides, hexaarylbiimidazole compounds, trihaloalkyl-substituted compounds, aromatic ketones, and the like. Particularly preferred photopolymerization initiators are organic boron salt compounds.

  Examples of the organic boron salt compounds include JP-A-8-217813, JP-A-9-106242, JP-A-9-188865, JP-A-9-188686, JP-A-9-188710, and the like. Organoboron ammonium compounds described in JP-A-6-175561, JP-A-6-175564, JP-A-6-157623, and the like, and JP-A-6-175553 Organoboron iodonium compounds described in JP-A-6-175554, etc., organoboron phosphonium compounds described in JP-A-9-188710, JP-A-6-348011, JP-A-7-128785, etc. JP-A-7-140589, JP-A-7-292014 Distribution, organic boron transition metal coordination complex compound described in JP-A-7-306527 Patent Publication, and the like. Examples of the counter anion described in JP-A-62-143044 and JP-A-5-194619 include cationic dyes containing an organic boron anion.

  Examples of aromatic onium salt compounds include aromatic onium salts of N, P, As, Sb, Bi, O, S, Se, Te or I. Examples of such aromatic onium salt compounds include compounds exemplified in Japanese Patent Publication No. 52-14277, Japanese Patent Publication No. 52-14278, Japanese Patent Publication No. 52-14279, and the like.

  Examples of organic peroxides include almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. For example, 3,3 ′, 4,4′-tetra (tert-butylperoxycarbonyl) ) Benzophenone, 3,3 ′, 4,4′-tetra (tert-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-hexylperoxycarbonyl) benzophenone, 3,3 ′, 4,4'-tetra (tert-octylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra (cumylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (p-isopropyl) Peryl ester such as cumylperoxycarbonyl) benzophenone, di (tert-butyldiperoxy) isophthalate System is preferred.

  Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, such as 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) ) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2 , 2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5 ′ Tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethylphenyl) -4, Examples include 4 ', 5,5'-tetraphenylbiimidazole.

  Specific examples of the trihaloalkyl-substituted compound are compounds having at least one trihaloalkyl group such as a trichloromethyl group and a tribromomethyl group in the molecule, and US Pat. No. 3,954,475, U.S. Pat.No. 3,987,037, U.S. Pat.No. 4,189,323, JP-A 61-151644, JP-A 63-298339, JP-A 4-69661, Trihalomethyl-s-triazine compounds described in JP-A-11-1553859, JP-A-54-74728, JP-A-55-77742, JP-A-60-138539, JP-A-61 No. 143748, JP-A-4-362644, JP-A-11-84649, etc. Oxadiazole derivatives, and the like. Moreover, the trihaloalkyl sulfonyl compound as described in Unexamined-Japanese-Patent No. 2001-290271 etc. which this trihaloalkyl group couple | bonded with the aromatic ring or the nitrogen-containing heterocyclic ring through the sulfonyl group is mentioned.

  Preferable examples of aromatic ketones include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FUOASSIER, J.A. F. RABEK (1993), P.A. 77-P. 177, a compound having a benzophenone skeleton or a thioxanthone skeleton, an α-thiobenzophenone compound described in JP-B-47-6416, a benzoin ether compound described in JP-B-47-3981, and JP-B-47-22326 Α-substituted benzoin compounds described in JP-A No. 47-23664, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, and JP-B-60-26483 Dialkoxybenzophenones, benzoin ethers described in JP-B-60-26403, JP-A-62-181345, p-di (dimethylaminobenzoyl) benzene described in JP-A-2-211452, A thio-substituted aromatic group described in JP-A-61-194062 Ton, an acylphosphine sulfide described in JP-B-2-9597, an acylphosphine described in JP-B-2-9596, a thioxanthone described in JP-B-63-61950, and JP-B-59-42864 Can be mentioned.

  The photopolymerization initiator used in the present invention includes compounds known as photoacid generators. As the photoacid generator, any compound can be used as long as it is a compound capable of decomposing by irradiation with light or electron beam and generating a strong acid such as hydrochloric acid or sulfonic acid or an acid such as Lewis acid. Examples of photoacid generators that can be used in the present invention include (k) aromatic diazonium salt compounds, (l) p-valic acid-o-nitrobenzyl ester, benzenesulfonic acid-o-nitrobenzyl ester, o- Sulfonic acid ester derivatives such as nitrobenzyl esters, (m) 9,10-dimethoxyanthracene-2-sulfonic acid-4-nitrobenzyl ester, pyrogallol trismethanesulfonate, naphthoquinonediazide-4-sulfonic acid esters, (n) Sulfones such as dibenzylsulfone and 4-chlorophenyl-4'-methoxyphenyldisulfone, (o) phosphate ester derivatives and (p) U.S. Pat. No. 3,332,936, JP-A-2-83638, JP 11-322707 A, JP 2000-1469 A, etc. And the like sulfonyl diazomethane compounds described.

  The organic boron salt compound which is a particularly preferable photopolymerization initiator in the present invention is composed of an organic boron salt, and the organic boron anion constituting the organic boron salt is represented by the following general formula (4).

In the formula, each of R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ may be the same or different, and represents an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group or heterocyclic group. To express. Among these, it is particularly preferable that one of R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ is an alkyl group and the other substituent is an aryl group.

  In the above-mentioned organoboron anion, a cation that forms a salt is simultaneously present. Examples of the cation in this case include alkali metal ions, onium ions, and cationic sensitizing dyes. Examples of onium salts include ammonium, sulfonium, iodonium and phosphonium compounds. When a salt of an alkali metal ion or onium compound and an organic boron anion is used, photosensitivity in the wavelength range of light absorbed by the dye is imparted by adding a sensitizing dye separately. Further, when an organic boron anion is contained as a counter anion of the cationic sensitizing dye, photosensitivity is imparted according to the absorption wavelength of the sensitizing dye. However, in the latter case, it is preferable to further contain an organic boron anion as a counter anion of the alkali metal or onium salt.

  The organic boron salt used in the present invention is a salt containing the organic boron anion represented by the general formula (4) shown above, and alkali metal ions and onium compounds are preferably used as cations forming the salt. The Particularly preferable examples of the onium salt with an organic boron anion include ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Specific examples of particularly preferred organic boron salts are shown below.

  In the present invention, a trihaloalkyl-substituted compound can be used as a photopolymerization initiator that can be used with an organic boron salt to realize higher sensitivity and higher contrast. Specifically, the trihaloalkyl-substituted compound is a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. As a preferable example, the trihaloalkyl group is a nitrogen-containing complex. Examples of the compound bonded to the ring group include s-triazine derivatives and oxadiazole derivatives, or trihaloalkylsulfonyl compounds in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocycle via a sulfonyl group. .

  Particularly preferred specific examples of trihaloalkyl-substituted nitrogen-containing heterocyclic compounds and trihaloalkylsulfonyl compounds are shown below.

  The said photoinitiator may be used independently and may be used in arbitrary 2 or more types of combination. The content of the photopolymerization initiator is preferably in the range of 1 to 100 parts by mass, more preferably in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the polymer containing a monomer having a polymerizable double bond as a copolymerization component. Particularly preferred.

  The sensitizing dye contained in the photopolymerizable photosensitive layer of the lithographic printing plate material of the present invention sensitizes the aforementioned photopolymerization initiator to the absorption maximum wavelength of the sensitizing dye. This makes it possible to cope with exposure by various lasers (for example, a blue-violet semiconductor laser and a near infrared laser). And when the said photoinitiator is an organic boron salt, it has the characteristic that the sensitivity with respect to various laser beams becomes very high by combining with this sensitizing dye. The sensitizing dye specifically sensitizes the decomposition of the photopolymerization initiator in a wavelength range of 380 to 1300 nm, and includes various cationic dyes, anionic dyes, and merocyanine as neutral dyes having no charge. , Coumarin, xanthene, thioxanthene, azo dyes and the like can be used. Specific examples of the sensitizing dye according to the present invention are shown below.

  When the sensitizing dye of the present invention is compatible with a blue-violet semiconductor laser (violet laser), a system in which light in the wavelength region of 380 to 430 nm is made photosensitive is particularly preferable, and the sensitizing dye absorbs in such a wavelength region. Particularly preferred specific examples used for such purposes are shown below.

  When the near-infrared laser is used as the sensitizing dye of the present invention, a system that imparts sensitivity to light in the wavelength region of 750 to 1100 nm is particularly preferable, and the sensitizing dye needs to have absorption in such a wavelength region. Particularly preferred specific examples used for such purposes are shown below.

  The above sensitizing dyes may be used alone or in any combination of two or more. The content of the sensitizing dye is preferably in the range of 0.1 to 50 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer containing a monomer having a polymerizable double bond as a copolymerization component. The range of is particularly preferable.

  Addition of a colorant can also be preferably performed as another element constituting the photopolymerizable photosensitive layer. As a colorant, it is used for the purpose of enhancing the visibility of the image area after exposure and development processing, and various kinds of carbon black, phthalocyanine dye, triarylmethane dye, anthraquinone dye, azo dye, etc. Dyes and pigments can be used.

  About the element which comprises a photopolymerizable photosensitive layer, in addition to the above-mentioned element, other elements can be additionally contained for various purposes. For example, it is also preferable to add inorganic fine particles or organic fine particles for the purpose of preventing blocking of the photosensitive layer.

  There is a preferred range for the dry coating amount of the photopolymerizable photosensitive layer, and it is preferably formed in the range of 0.2 g to 5 g per square meter in dry mass, and the most preferred range is 0.5 g to 3 g per square meter. Range.

  The lithographic printing plate material of the present invention may have a protective layer on the photosensitive layer as viewed from the support, and in the photopolymerizable photosensitive layer, a factor that promotes deactivation of radical species generated by laser exposure. A protective layer with the ability to further block oxygen in water is preferable. Especially when the laser light source of the exposure machine is a violet laser, a sufficient amount of energy cannot be obtained with a commercially available light source. Is particularly preferred. It is preferable to use a water-soluble polymer compound having relatively excellent crystallinity for the protective layer, and specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl alcohol / vinyl phthalate copolymer. Examples thereof include water-soluble polymers such as polymers, vinyl acetate / crotonic acid copolymers, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide, and these can be used alone or in combination. . Of these, the use of polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100% and a polymerization repeating unit in the range of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC made by Kuraray Co., Ltd. , PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA -420, PVA-613, L-8 and the like.

  The content of the polyvinyl alcohol in the protective layer is preferably 50% by mass or more, more preferably 70% by mass or more in terms of solid content.

  Polyvinyl alcohol, other water-soluble polymers, various organic compounds, and inorganic compounds may be added to the protective layer of the present invention. A surfactant may be added for the purpose of improving the coating property for coating on the photopolymerizable photosensitive layer.

  The dry mass of the protective layer of the present invention is selected in consideration of fogging, adhesion and scratch resistance in addition to oxygen barrier properties and development removability, but is preferably between 0.1 g and 3 g per square meter.

  In the lithographic printing plate material development processing method of the present invention, the exposed portion of the photosensitive layer undergoes a photopolymerization reaction, so that it remains as an image (image portion), and the unexposed portion swells or develops due to the development processing. By being dissolved, the hydrophilic layer is exposed on the surface (non-image area), and a lithographic printing plate is obtained.

  As a layer structure of this lithographic printing plate material, in addition to a layer structure in which an intermediate layer, a hydrophilic layer, and a photosensitive layer are provided in this order on the upper part of a plastic film substrate, for example, on the upper part of the photosensitive layer (with the support on the bottom). A protective layer may be provided, or a back layer may be provided on the back side of the plastic film substrate (the surface opposite to the photosensitive layer surface when viewed from the substrate).

  As a development processing method of the lithographic printing plate material of the present invention, there is a chemicalless development substantially containing no alkali agent. This development is a method using a neutral developer (chemicalless developer) having a developer pH value in the range of 4.0 or more and less than 10.0, and a more preferable pH value of the developer is 4.0 or more. It is less than 8.0. Moreover, as long as the pH value is within the above range, other additives may be contained. Examples of such additives include ethanol, isopropanol, n-butyl cellosolve, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, benzyl alcohol and the like. It is possible to add various organic solvents or surfactants such as anionic, cationic and nonionic surfactants. The amount of the additive varies depending on the type and purpose of the additive, but is preferably 10 parts by mass or less, more preferably 3 parts by mass or less with respect to 100 parts by mass of water. Furthermore, a commercially available printing plate surface protecting solution or a printing plate fountain solution can be used. This processing method may include, for example, a water washing step after the development step.

  There is on-press development as a development processing method of the lithographic printing plate material of the present invention. This method is a system in which a plate after exposure is mounted on a printing machine and development is performed on the printing machine without going through the above-described development process. On-press development is performed by using a photopolymerizable photosensitive layer in an unexposed area as a blanket. There are a method of transferring and transferring to a printing paper or the like through a blanket, a method of dissolving or dispersing a photopolymerizable photosensitive layer in an unexposed portion in a moistening liquid via a roll for moisturizing liquid, and the like.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples as well as the effects.

<Intermediate layer>
The following intermediate layer is applied on a plastic film substrate having a thickness of 100 μm with a wire bar, dried for 10 minutes with a dryer at 50 ° C., and the dried product is further heated with a dryer at 40 ° C. for 2 days. went. In addition, the sample from which the dry mass from which an intermediate | middle layer differs was changed by changing the kind of wire bar (it describes in Table 1).

<Intermediate layer prescription>
Gelatin Co., Ltd. NP3000 MW 3000 molecular weight about 120,000 10 parts by weight Polymer latex Nippon A & L Co., Ltd. Smartex listed in Table 1 Cross-linking agent H-9 1 part by weight ion-exchanged water 100 parts by weight pH adjuster (sodium hydroxide) Adjust pH to 5.0 with aqueous solution or sulfuric acid solution)

  In addition, among the intermediate | middle layer application | coating samples of Table 1, the comparison A is a sample which has not provided said polymer latex.

<Hydrophilic layer>
On the above intermediate layer coated sample (surface of the intermediate layer), the following hydrophilic layer formulation is applied with a wire bar so that the dry mass is 1.5 g (per square meter), and a 50 ° C. dryer is applied. And dried for 10 minutes to obtain a lithographic printing plate support of the present invention and comparative.

<Hydrophilic layer formulation>
Water-soluble polymer WP-4 1 part by mass Inorganic fine particle Nissan Chemical Co., Ltd. Snowtex PS-M (particle size 80-150 nm)
1.5 parts by mass Crosslinker H-9 0.5 parts by mass pH adjuster (pH adjusted to 4.0 with aqueous sodium hydroxide or sulfuric acid)
10 parts by mass of ion exchange water

<Photosensitive layer>
Application of a photopolymerizable photosensitive layer on the lithographic printing plate support (hydrophilic layer surface) so that the dry weight is 1.5 g (per square meter) with a wire bar in the following photosensitive layer formulation. And drying for 10 minutes in a dryer at 70 ° C. Further, the protective layer is coated on the photosensitive layer so that the dry weight is 1.5 g (per square meter) with a wire bar according to the following protective layer formulation. Coating was performed, and drying was performed for 10 minutes in a dryer at 70 ° C., and the lithographic printing plate material of the present invention and a comparison were obtained.

<Photosensitive layer formulation>
Polymer SP-1 1 part by weight Photopolymerization initiator BC-6 0.1 part by weight Photopolymerization initiator T-4 0.1 part by weight Sensitizing dye S-14 0.05 part by weight Colorant Victoria Blue 0.2 Part by mass Acetone 5 parts by mass Ethanol 5 parts by mass Tetrahydrofuran 10 parts by mass

<Protective layer prescription>
PVA105 (polyvinyl alcohol manufactured by Kuraray Co., Ltd.) 1 part by mass Ion-exchanged water 20 parts by mass

<Exposure test>
The obtained lithographic printing plate material was exposed to an image at an exposure amount of 100 μJ / m ² using an external drum type plate setter (Mitsubishi Paper Co., Ltd. VIPLAS) equipped with a 405 nm violet laser.

<Development method>
The lithographic printing plate material drawn above was immersed in ion-exchanged water adjusted to 30 ° C. for 15 seconds, and lightly rubbed with a cellulose sponge to remove unexposed portions.

<Gelatin dissolution rate>
The gelatin dissolution rate was determined by finely cutting a support having an intermediate layer coated on a plastic film substrate, preparing a total of 100 cm ^{2 of} this piece, putting it in 30 ml of 10 ml of pure water, The mixture was stirred for 1 minute with SHAKING BATHS manufactured by the same company, and this liquid was collected, and the amount of gelatin dissolved in the liquid was quantified using an ultraviolet / visible absorption spectrum measuring device (US-O V-560). . This value is shown in Table 1.

<Ink fillability>
Using the printing machine Heidelberg KORD (trademark of offset printing machine manufactured by Heidelberg), BestOne black N ink (manufactured by T & K TOKA Co., Ltd.) and a commercially available PS plate moisturizer (Astro Mark III manufactured by Nikken Chemical Co., Ltd.) 20000 sheets were printed, and ink inking properties at the initial printing and at the end of printing were evaluated according to the following criteria. The results are shown in Table 1.
Initial printing ○: The number of sheets reaching 90% of the reflection density value of the 1000th sample is less than 20 sheets Δ: The number of sheets reaching 90% of the reflection density value of the 1000th sample is 20 sheets or more and less than 50 sheets × : When the number of sheets reaching 90% of the reflection density value of the 1000th sample is 50 or more, ○: The reflection density at the end of printing is 90% or more of the reflection density of the 1000th sample Δ: At the end of printing The reflection density at 80% or more and less than 90% of the reflection density of the 1000th sample x: The reflection density at the end of printing is less than 80% of the reflection density of the 1000th sample

  Further, the printing durability and soil resistance were examined under the printing conditions described above. The printing durability was observed with a 50 × magnifier on the 20000th printed matter for defects in the 5% halftone dot image area. As for the soil resistance, the non-image portion of the 2000th printed material was visually observed. As a result, all of the lithographic printing plate support and the lithographic printing plate material of Comparative A to I and Inventions 1 to 15 had good printing durability and stain resistance.

  From the results shown in Table 1, it can be seen that the present invention can provide a lithographic printing plate support and a lithographic printing plate material that are excellent in ink deposition without lowering the printing durability and stain resistance during printing.

Claims (2)

  A support for a lithographic printing plate comprising a hydrophilic layer on a plastic film substrate, wherein the intermediate layer located between the plastic film substrate and the hydrophilic layer contains a polymer latex, gelatin and a crosslinking agent. A support for a lithographic printing plate, wherein the amount of the polymer latex is from 10 to 100% by mass based on the amount of the gelatin.   On the hydrophilic layer of the lithographic printing plate support according to claim 1, a copolymer having a phenyl group and a sulfonic acid group each having a vinyl group substituted on a side chain, a photopolymerization initiator, and a sensitizing dye. A lithographic printing plate material having a photosensitive layer.