JP2008233820A - Support for lithographic printing plate, manufacturing method of lithographic printing plate, and photosensitive lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a support for a lithographic printing plate which has high water retention and excellent printing durability, as regards a film support which has a hydrophilic layer having hydrophilic surface as the film support and uses the hydrophilic layer as the no-image part of a printing plate. <P>SOLUTION: The support for the lithographic printing plate, which has, on a plastic film base, an undercoat layer containing self-emulsifying isocyanate and a water-dispersible polyurethane and the hydrophilic layer, containing a water-soluble polymer and colloidal silica, in mass proportion of 3:1 to 1:5 thereupon. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate film support using a plastic film support provided with a specific undercoat layer, further provided with a hydrophilic layer, and using the hydrophilic layer as a non-image part of a printing plate. . Further, as a method for forming an image on such a hydrophilic layer, an ink jet recording method, a thermal transfer method, and a photopolymerization method are applied, and a method for producing a lithographic printing plate excellent in printability and photosensitivity are used. It relates to lithographic printing plate materials.

  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, paper or film is used as a support, and silver halide is used as a support. As a lithographic printing plate material using the silver salt diffusion transfer method (DTR method) used, particularly a lithographic printing plate material having a physical development nucleus on a silver halide emulsion layer, for example, US Pat. No. 3,728,114, 4,134,769, 4,160,670, 4,336,321, 4,501,811, 4,510,228, 4,621 , 041 and the like are widely used. In these lithographic printing plate materials, 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 developed. The silver salt complexing agent in the liquid is converted into 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 support such as a film is cheaper and easier to handle than an aluminum support, and particularly in a plate making system using the CTP method, an exposure apparatus. As a laser image setter, the printing plate material can be stored in the apparatus very compactly, for example, as a roll-shaped lithographic printing plate material.

  However, the lithographic printing plate material using the flexible support as described above is inferior in water retention of the non-image area at the time of printing as compared with the case of an aluminum support such as a PS plate, and easily causes scumming. In addition, since there is a problem with the printing durability of the image portion, it is often used under limited printing conditions such as a small number of copies to a medium number of copies.

  For example, Japanese Patent Application Laid-Open No. 2001-75237 (Patent Document 1) describes a method for improving adhesiveness with a support when a hydrophilic layer is provided on the film support. According to this, a lithographic printing plate using the above silver salt diffusion transfer system is disclosed by a film support provided with an undercoat layer containing a self-emulsifiable isocyanate compound having an ethylene oxide repeating unit and two or more isocyanate groups. However, in this method, the adhesion between the water-soluble polymer layer mainly composed of gelatin and the support is good, but the hydrophilicity of the water-soluble polymer layer mainly composed of gelatin which becomes a non-image part as a printing plate Since the water-retaining property is inferior to that of the aluminum support surface of the PS plate, the above problems have occurred.

  Examples of providing a hydrophilic layer on the surface of the support include, for example, a hydrophilic resin layer made of a (meth) acrylate-based polymer having a hydroxyalkyl group described in Japanese Patent Publication No. 49-2286, and Japanese Patent Publication No. 56-2938. A hydrophilic layer composed of the urea resin and the pigment described above, a hydrophilic layer obtained by curing an acrylamide polymer described in JP-A-48-83902 with aldehydes, and JP-A-62-280766. A hydrophilic layer obtained by curing a composition containing the water-soluble melamine resin, polyvinyl alcohol and water-insoluble inorganic powder described above, and a repeating unit having an amidino group in the side chain described in JP-A-8-184967. A hydrophilic layer obtained by curing a water-soluble polymer, a hydrophilic (co) polymer described in JP-A-8-272087, A hydrophilic layer cured with a solvated tetraalkyl orthosilicate, a hydrophilic layer having an onium group described in JP-A-10-296895, and a crosslinked hydrophilic group having a Lewis base moiety described in JP-A-11-311861 A hydrophilic layer obtained by three-dimensionally cross-linking a hydrophilic polymer by interaction with a polyvalent metal ion, a hydrophilic layer containing a hydrophilic resin and a water-dispersible filler described in JP-A No. 2000-122269, and the like. However, the water retention of the hydrophilic layer obtained in any of the systems did not reach the level of the PS plate, and it was a support that was liable to cause soiling.

  In JP-A-2000-158839 (Patent Document 2), a hydrophilic layer containing a water-soluble polymer having a carboxyl group such as polyacrylic acid and colloidal silica in a specific ratio is formed on a film support, and the ink is removed. The result of good releasability is shown. However, water-soluble polymers such as polyacrylic acid gradually dissolve in the dampening liquid during printing, and the hydrophilic layer swells, causing the hydrophilic layer to peel off or the image part to peel off depending on the printing conditions. There was a problem. Furthermore, when compared with the printing performance of the PS plate, the water retention was clearly inferior.

  Japanese Patent Application Laid-Open No. 2004-167773 (Patent Document 3) discloses a lithographic printing plate material in which a hydrophilic layer and an image forming layer are provided on a substrate, and the styrene copolymer or acrylic copolymer is formed on the substrate surface. A printing plate material having an undercoat layer mainly composed of a polymer is disclosed. It is described that the hydrophilic layer described in this specification has a porous structure made of colloidal silica or the like. Similarly, Japanese Patent Application Laid-Open No. 9-99662 (Patent Document 4) also describes a porous hydrophilic layer formed by agglomeration of fine particles such as vapor phase method silica. All of these had the property that ink at the time of printing easily entered the inside of the porous pores, and scumming was liable to occur. In addition, the undercoat layer described in any specification has a problem that the adhesiveness with such a hydrophilic layer is not sufficient and an image portion is lost during printing.

  As described above, there is a demand for a printing plate having a flexible support such as a film in a printing plate using the CTP method, but a lithographic printing plate using a silver salt diffusion transfer method (DTR method). The development processing is complicated, the liquid property management of the processing solution is troublesome, and there is a problem in maintaining stable quality. Under these circumstances, processless printing plates that do not require development processing, or chemical-free printing plates that do not use chemicals and that can be developed with water, are eagerly desired, especially flexible, processless or chemical-free printing plates. The expectation for is great.

  To date, processless printing plates generally use the ink jet method or thermal transfer method, and methods that use the ablation method, heat fusion type, and micro methods that use laser light. Capsule type and peeling type are known. Examples of using the ink jet method or the thermal transfer method include systems described in the above-mentioned Patent Documents 2, 3 and 4. 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 utilizing laser light, for example, JP-A-8-507727, JP-A-6-186750, JP-A-6-199064, JP-A-7-314934, JP-A-10-58636, The thing described in 244773 gazette is mentioned. Problems with the ablation method include contamination of the optical system due to debris generated by ablation and the need to provide a special cleaning mechanism for removing the ablation debris. In addition, since it takes time for exposure, the productivity is inferior. 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. 2004-237582, and the like. However, there are problems such as low sensitivity and poor adhesion to the support, causing problems in printing durability. It is done. With respect to the microcapsule type, light can be 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. Since a high-sensitivity photopolymerization system is used, the sensitivity is good, but it is necessary to remove the photosensitive layer by applying ink after spreading dampening water over the entire plate surface during on-press development. However, it is not always easy to remove the photosensitive layer in the humidification mechanism of various printing presses, and depending on the type of printing press, it may be difficult to remove the photosensitive layer, resulting in a problem of background contamination. .

  As a system belonging to the peeling type, for example, as described in JP-A-7-191457, JP-A-7-325394, JP-A-10-3166, etc., a photopolymerizable photosensitive layer is formed on a hydrophilic layer. Examples thereof include a method of forming an image comprising a photosensitive layer cured on a hydrophilic layer by providing a layer, adhering the receptor sheet after exposure, and transferring an unexposed portion onto the receptor sheet. In this method, it is considered that it is difficult to remove a fine shadow portion halftone dot portion, and the disadvantage is that the removal of the photosensitive layer on the hydrophilic layer becomes insufficient and soiling is likely to occur.

  Since processless printing plates using laser light as described above generally require high energy for image formation, a near infrared semiconductor laser is used as a light source for exposure. Moreover, most of them use an aluminum plate as a support. On the other hand, a processless printing plate in which a hydrophilic layer is formed on a film support and a heat-meltable fine particle (wax or the like) layer is provided thereon is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-50616 and 2004. -237592 (patent document 5). By using a film as a printing material, the plate material is stored in a roll shape, so that the exposure apparatus is small and compact, and has the advantage that the handling and cost of the plate material are greatly improved. However, there are various problems in terms of quality performance. According to these published patent publications, the hydrophilic layer is composed of hydrophilic fine particles such as colloidal silica and montmorillonite, and the image is a wax that is heat-sealed. There were problems of poor printing durability and relatively low sensitivity due to insufficient adhesion at the interface of the layers.

JP 2003-215801 A (Patent Document 6) uses a cationic or anionic water-soluble polymer in which a vinyl group is bonded to a side chain via a phenyl group as a water-developable photosensitive composition. Further, it is disclosed that a water-developable printing plate can be produced by forming this on a substrate having a hydrophilic surface. In this case, as a substrate having a hydrophilic surface, a silicate-treated aluminum plate or a film support provided with a hydrophilic undercoat layer is exemplified. However, in any combination, scumming is caused under various printing conditions. It was difficult to satisfy both the properties of prevention and printing durability at the same time, and it was necessary to study materials and structures for further optimization. An object of the present invention is to carry out further studies and find an optimum support for achieving both the prevention of scumming and printing durability.
JP 2001-75237 A JP 2000-158839 A JP 2004-167773 A JP-A-9-99662 Japanese Patent Application Laid-Open No. 2004-237592 JP 2003-215801 A

  The present invention relates to a support for a lithographic printing plate having a hydrophilic layer having a hydrophilic surface with a plastic film as a base, and utilizing this hydrophilic layer as a non-image part of a printing plate, and has high water retention, Another object is to provide a lithographic printing plate support having good printing durability. Furthermore, it is to provide a lithographic printing plate production method and a photosensitive lithographic printing plate material excellent in printability by adapting three types of ink jet recording method, thermal transfer method and photopolymerization method.

The object of the present invention is to have a subbing layer containing a self-emulsifiable isocyanate and a water-dispersible polyurethane on a plastic film substrate, on which a water-soluble polymer and colloidal silica are mixed at a mass ratio of 3: 1 to 1: Basically, this is achieved by using a lithographic printing plate support having a hydrophilic layer comprising 5 and further carrying out the following items (1) to (3).
(1) A method for producing a lithographic printing plate, comprising depositing an image-forming material imagewise on the lithographic printing plate support by an ink jet method to form an oleophilic image layer on a part of the surface of the hydrophilic layer.
(2) After the thermal transfer layer of the thermal transfer sheet having the thermal transfer layer on the sheet is adhered to the surface of the hydrophilic layer of the lithographic printing plate support, a thermal head or laser light is applied from the sheet side. A method for producing a lithographic printing plate, wherein a thermal transfer layer corresponding to the heated portion is transferred onto the hydrophilic layer by imagewise heating to form an oleophilic image layer.
(3) A photosensitive lithographic printing plate material in which a photocurable photosensitive layer is provided on the surface of the hydrophilic layer of the lithographic printing plate support is used.

  According to the present invention, a support for a lithographic printing plate having water retention equivalent to that of a PS plate and having good printing durability is provided. Furthermore, a lithographic printing plate production method and a photosensitive lithographic printing plate material excellent in printability are provided by adapting three types of ink jet recording method, thermal transfer method and photopolymerization method.

  Hereinafter, the present invention will be described in detail. Typical examples of the plastic film substrate include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, and cellulose nitrate. Polyethylene terephthalate and polyethylene naphthalate are preferably used.

  The self-emulsifiable isocyanate compound used in the present invention means a compound having an ethylene oxide repeating unit and two or more isocyanate groups, such as JP-B-55-7472 (US Pat. No. 3,996,154), Self-emulsifying isocyanates as described in JP-A-5-222150 (US Pat. No. 5,252,696), JP-A-9-71720, JP-A-9-328654, JP-A-10-60073, etc. Point to. Specifically, for example, a polyisocyanate having an isocyanurate structure of a cyclic trimer skeleton formed from an aliphatic or alicyclic diisocyanate in a molecule, or a polyisocyanate having a burette structure, a urethane structure or the like in the molecule. A very preferable example is a polyisocyanate compound having a structure obtained by adding a polyethylene glycol or the like having one terminal etherification to only a part of the polyisocyanate group as a base polyisocyanate. A method for synthesizing an isocyanate compound having such a structure is described in the above publication. As a specific example of such an isocyanate compound, a polyisocyanate based on cyclic trimerization using hexamethylene diisocyanate or the like as a starting material is commercially available. For example, deyuranate WB40 or Asahi Kasei Kogyo Co., Ltd. It is available under names such as WX1741.

  In the isocyanate compound as described above, since the ethylene oxide repeating unit is directly bonded to the hydrophobic base polyisocyanate, an emulsion in which the polyisocyanate portion is separated from the aqueous layer in water is formed, and the polyethylene oxide portion is It has a self-emulsifying function to stabilize the emulsion. Because of this, isocyanate groups that react with water and deactivated continue to exist stably even in water, so even when added to an aqueous coating solution, the pot life is long. In the film formation process in which the moisture in the film evaporates, the emulsion state is quickly destroyed, and the crosslinking reaction proceeds quickly by diffusing into the film.

  In the self-emulsifiable isocyanate compound, the length of the ethylene oxide repeating unit is preferably about 5 to 50 repeating units. If it is less than this, the self-emulsifying property is poor and it is difficult to show a stable emulsifying property in an aqueous solution, and if it has 50 or more repeating units, it tends to crystallize and become a solid, which is not preferred. Furthermore, the isocyanate content in the self-emulsifiable isocyanate compound is preferably in the range of 8 to 25% by mass.

  In the present invention, at least one undercoat layer is provided on a plastic film substrate using a water-dispersible polyurethane resin together with the self-emulsifiable isocyanate compound. Examples of water dispersible polyurethane resins include self-emulsifying polyurethane resins. As the self-emulsifying polyurethane resin, those having a hydrophilic group such as a sulfonic acid group, a carboxy group, a hydroxyl group, and a polyethyleneoxy group in the polyurethane structure are preferable, and commercially available various polyurethane emulsions are preferably used. Examples of commercially available products include various hydran series from Dainippon Ink Industries, Ltd., various permarine series from Sanyo Chemical Industries, Ltd., and the like.

The content of the self-emulsifiable isocyanate compound in the undercoat layer is suitably in the range of ^{1mg / m 2 ~10g / m 2} , preferably in the range from ^{1mg / m 2 ~1g / m 2} . The self-emulsifiable isocyanate compound is used in the range of 0.1 to 200% by mass, preferably in the range of 1 to 50% by mass with respect to the water-dispersible polyurethane resin described above.

  In the undercoat layer, inorganic fine particles such as colloidal silica having a particle size corresponding to the thickness of the undercoat layer (in the range of about 0.01 to 3 μm, which is about several times the thickness of the undercoat layer) It may contain polymer beads and the like. When the undercoat layer is a single layer, the film thickness (dry film thickness) is preferably formed in the range of 0.01 μm to 1 μm. If the film thickness is less than this, the effect as an undercoat layer may not be obtained, and if it is formed with a thickness exceeding 1 μm, adverse effects such as deterioration of the curl property of the film may be observed. is there.

  The coating and drying of a single undercoat layer containing a self-emulsifiable isocyanate compound and a water-dispersible polyurethane resin can be carried out before or after stretching of the film, or off-line in the film production process. In either case, good adhesion can be obtained. From the viewpoint of productivity, it is preferable to apply and dry the undercoat layer before stretching the film. Usually, heat treatment is performed after stretching in the film formation process, but there is no problem with heat treatment conditions even if the heat treatment is performed in the range of room temperature to about a few hundred degrees or 250 ° C. exceeding 200 ° C. .

  The support of the present invention has a hydrophilic layer comprising a water-soluble polymer and colloidal silica in a mass ratio of 3: 1 to 1: 5 on the undercoat layer. The hydrophilic layer containing colloidal silica used in the present invention will be described. Colloidal silica as used herein refers to various shapes such as a spherical shape, a needle shape, an indefinite shape, or a necklace shape in which spherical particles are connected, with an average particle diameter of 5 to 200 nm measured by a light scattering system particle size distribution meter. A silica sol having a particle size and stably dispersed in water is 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 Catalyst Kasei Kogyo Co., Ltd. Examples of the necklace-like 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.

  As such colloidal silica contained in the hydrophilic layer, each type of colloidal silica may be used alone, or different types of colloidal silica may be mixed and used in various proportions. In particular, necklace-like silica with good film-forming properties is preferred, and in combination with this, the use of spherical colloidal silica with various particle sizes increases the coating strength of the hydrophilic layer and allows the non-image area to be ground under printing conditions. An effective and preferred system is obtained to prevent soiling.

  In the present invention, the hydrophilic layer needs to contain a water-soluble polymer. The water-soluble polymer is preferably a system that does not cause aggregation of the colloidal silica when mixed with the above-mentioned various colloidal silicas, and maintains a uniform dispersion state. And a system in which the water-soluble polymer does not cause phase separation, forms a uniform film, and does not generate a porous structure. It is important that the water-soluble polymer functions to prevent the porous structure due to colloidal silica and to prevent the ingress of ink during printing by filling the gaps between particles. Water-soluble polymers can be used.

  Examples of water-soluble polymers that can be used in the present invention include polyacrylamide, polyvinyl pyrrolidone, polyvinyl alcohol, modified starch, and modified cellulose. Furthermore, as the most preferable water-soluble polymer, a polymer represented by the following general formula I can be mentioned because it gives a homogeneous film when used by mixing with colloidal silica.

  In the above formula, X represents mass% of repeating units in the copolymer composition, and represents any numerical value from 1 to 40. The repeating unit A represents a repeating unit having a carboxyl group or an amino group as a reactive group. The repeating unit B represents a repeating unit having a hydrophilic group necessary for making the copolymer water-soluble.

  When the water-soluble polymer represented by the above general formula I is used after adding a cross-linking agent described later, a reactive group for efficiently proceeding a cross-linking reaction between the water-soluble polymer and such a cross-linking agent. Is preferably carried out in the molecule of the water-soluble polymer. Furthermore, it is also preferable to use a crosslinking reaction that contributes to adhesion at the interface between the undercoat layer and the hydrophilic layer. That is, since the undercoat layer contains a self-emulsifiable isocyanate compound, the water-soluble polymer in the hydrophilic layer reacts with the isocyanate group or the amino group generated by the decomposition thereof and the crosslinking agent in the hydrophilic layer. However, it is very preferable to cause a cross-linking reaction with the undercoat layer to express good adhesiveness. Particularly preferred examples of the reactive group contained in the water-soluble polymer in such a hydrophilic layer include a carboxyl group or an amino group. 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 I, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid, maleic acid Monoalkyl esters, monoalkyl esters of fumaric acid, 4-carboxystyrene, carboxyl-containing monomers such as acrylamide-N-glycolic acid and their salts, allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylamide, 4-aminostyrene, 4- Amino group-containing monomers such as minomethylstyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-vinylbenzyl) amine, 4-vinylpyridine, 2-vinyl Examples thereof include nitrogen-containing heterocyclic-containing monomers such as pyridine and N-vinylimidazole, but are not limited to these examples.

  In the above general formula I, X, which is the proportion of the repeating unit A in the copolymer, is in the range of 1 to 40. Below this range, even if the crosslinking reaction proceeds, the water resistance cannot be exerted, and if it is above this range, the effect of introduction of the repeating unit B for imparting water solubility described below is reduced, and the hydrophilic layer with respect to water Affinity may be reduced.

  Furthermore, as the monomer for giving the repeating unit B in the general formula I, vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, 2-acrylamide- Sulfo group-containing monomers such as 2-methylpropanesulfonic acid and salts thereof, phosphate group-containing monomers such as vinylphosphonic acid and salts thereof, dimethyldiallylammonium chloride, 2-trimethylammonium chloride, 2-trimethylammonium chloride Ethyl methacrylate, 2-triethylammonium ethyl acrylate chloride, 2-triethylammonium ethyl methacrylate chloride, 3-trimethylammonium propylacrylamide chloride, 3-dimethylaminopropyl Pyrmethacrylamide, quaternary ammonium salts such as 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 A, or any two or more kinds may be used. Examples of preferable water-soluble polymers in the present invention are shown below.

  When such a water-soluble polymer is used, there is a preferred ratio of colloidal silica, and the mass ratio of water-soluble polymer to colloidal silica is in the range of 3: 1 to 1: 5. If the water-soluble polymer is contained in the hydrophilic layer in a ratio exceeding 3: 1 compared to colloidal silica, the adhesion to the oleophilic image formed from the ink jet method, thermal transfer method and photo-curing photosensitive layer described later is reduced. The printing durability may be reduced during printing. In addition, when the ratio of the water-soluble polymer to colloidal silica is 1: 5 or less, the adhesion to the oleophilic image is good and the printing durability is sufficient, but the printing ink component is adsorbed in the gap between the colloidal silica particles. Doing so may easily cause scumming. It is also preferable that the water-soluble polymer is cross-linked and water-resistant with a cross-linking agent, which will be described later, but even if no cross-linking agent is added, if the water-soluble polymer is included within the above range, good printability is obtained. Can be shown.

  Examples of the crosslinking agent added to the hydrophilic layer according to the present invention for crosslinking the water-soluble polymer include various known compounds. Specifically, an epoxy compound, an aziridine compound, and an isocyanate compound are preferable examples. Hereinafter, specific examples of such crosslinking agents will be described with chemical formulas.

  As the epoxy compound, a compound having two or more epoxy groups in the molecule and water-soluble is preferably used. These epoxy compounds are relatively stable in water under neutral to weakly acidic conditions, and when a coating liquid for forming a hydrophilic layer is prepared, the coating liquid has a long life and is extremely advantageous in continuous production. . Examples of preferred epoxy compounds are shown below.

  Examples of preferred compounds as aziridine compounds are shown below.

  As the isocyanate compound, a compound that is stable in water is preferable, and the self-emulsifiable isocyanate compound and the blocked isocyanate compound described above are preferably used. Examples of the blocked isocyanate compound include blocks blocked with bisulfite, alcohols, lactams, oximes, active methylenes, etc., as disclosed in, for example, JP-A-4-184335 and JP-A-6-175252. Isocyanates are preferably used.

  There is a preferred range for the ratio of the various cross-linking agents and the water-soluble polymer 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 the water-soluble polymer, and if it is 1 part by mass or less, the crosslinking water resistance is insufficient, and the hydrophilic layer is peeled off during printing. There is a case. On the other hand, when 40 parts by mass or more is used, the affinity of the hydrophilic layer for water decreases, which may cause soiling.

  There is a preferred range for the solid content coating amount of the hydrophilic layer, and it is preferably formed on the support in the range of 0.5 g to 20 g per square meter in dry mass. Dirt is likely to occur, and cracks may easily occur in the coating film when applied over 20 g per square meter. The most preferred range is from 1 g to 5 g per square meter.

  It is also preferable to add other inorganic fine particles to the hydrophilic layer in addition to the above elements. For example, by adding various grades of silicia obtained from Fuji Silysia Chemical Co., Ltd. as porous microparticles of μm size, favorable effects such as improvement of hydrophilicity and prevention of blocking of the hydrophilic layer can be obtained. Alternatively, the same preferable effect can be obtained by adding crystalline aluminosilicate known as zeolite, smectite (montmorillonite or the like), talc or the like as layered clay mineral fine particles. When these porous silica fine particles, zeolite, or layered clay mineral fine particles are added and used, there is a preferable ratio to colloidal silica, which is 1 to 50 parts by mass with respect to 100 parts by mass of colloidal silica. If the addition amount is less than this, the effect is difficult to recognize, and if it is added in excess of 50 parts by mass, the smoothness of the coating film is impaired and the image quality is lowered, which may be undesirable.

  An important point in comparison with the prior art is that a hydrophilic layer obtained by the present invention as described above is formed on a plastic film substrate provided with a specific undercoat layer related to the present invention, which will be described later. When each of the ink jet recording method, thermal transfer method and photopolymerization method is applied, the adhesion between the image area and the support becomes extremely good, resulting in high printing durability and good water retention, that is, generation of soiling. One point is prevention. In the prior art, when a hydrophilic layer free from scumming is formed on a plastic film substrate, there is a problem that sufficient adhesiveness with the substrate cannot be secured and printing durability is lowered. A feature of the present invention is that it is possible to achieve both water retention and printing durability by forming a highly hydrophilic hydrophilic layer having the above-described configuration on a plastic film substrate provided with a specific undercoat layer. It is a feature.

  An image can be formed on the lithographic printing plate support of the present invention by the following ink jet recording system, thermal transfer system and photopolymerization system, but is not limited to these methods.

  Examples thereof include a method in which an image forming material is attached in an image-like manner by a known ink jet method to form an oleophilic image layer on a part of the surface of the hydrophilic layer. 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 A combination of soybean oil with an organic acid or anhydride (eg, phthalic acid, maleic acid, sebacic acid or anhydride), or an organic peroxide (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′— Mechi Alluron 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, glycerin trimethylolpropane, polyethylene glycol, polypropylene glycol); and acrylate or methacrylate monomers or oligomers (eg, methoxydi) Tylene 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 Recall 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 Ethane trimethacrylate, trimethylol propane triacrylate, trimethylol ethane triacrylate, trimethylol methane triacrylate, trimethylol prop Diacrylate mono coconut fatty acid ester, tetramethylolmethane tetraacrylate, dibromo neopentyl 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 on a film is adhered to the hydrophilic layer surface of the lithographic printing plate support of the present invention. Next, the film side 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 And silica, calcium carbonate, carbon black, titanium white and the like.

  It is also preferable to form an image layer by coating a known photocurable photosensitive layer on the hydrophilic layer, and after exposure, the unexposed portion is removed by water development or dampening water on a printing machine. I can do it. The photosensitive layer may be any material that can be used as a photosensitive layer of a photosensitive lithographic printing plate. Such a photosensitive layer is generally composed of a photopolymerization initiator and a compound having a polymerizable double bond in the molecule. A system using a polymer having a heavy bond is preferred. In particular, as a system for providing a photosensitive layer developable with water, for example, a photosensitive layer described in JP-A No. 2003-215801 is a preferable system. Namely, a photosensitive water-containing polymer having a phenyl group substituted with a vinyl group in the side chain and a cationic group or a water-soluble polymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonate group A system using the composition as a photosensitive layer is a preferred example. Examples of such preferred polymers are shown below.

  A particularly preferred photosensitive layer according to the present invention contains a polymer having both a sulfonic acid group and a phenyl group to which a vinyl group is bonded via a linking group containing a hetero ring in the side chain. The phenyl group having a vinyl group bonded thereto via a linking group containing a heterocycle has a group represented by the following general formula II in the side chain.

In the formula, Z represents a linking group containing a heterocycle, and R ₁ , R ₂ , and R ₃ are a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group. A group, an aryl group, an alkoxy group, an aryloxy group, and the like, and these groups may be substituted with an alkyl group, an amino group, an aryl group, an alkenyl group, a carboxy group, a sulfo group, a hydroxy group, or the like. R ₄ represents a group or an atom that can be substituted with a hydrogen atom. n represents 0 or 1, m represents an integer of 0 to 4, and k represents an integer of 1 to 4. Examples of the heterocyclic group include a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, a tetrazole ring, an isoxazole ring, an oxazole ring, an oxadiazole ring, an isothiazole ring, a thiazole ring, a thiadiazole ring, a thiatriazole ring, and an 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 ring, quinoxaline ring, etc. A nitrogen-containing heterocyclic ring, a furan ring, a thiophene ring, and the like, and a substituent may be bonded to these heterocyclic rings. Examples of the group represented by the general formula II are shown below, but are not limited to these examples.

Among the groups represented by the general formula II, preferred ones exist. That is, it is preferable that R ₁ and R ₂ are hydrogen atoms and R ₃ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.). Furthermore, as the linking group, those containing a thiadiazole ring are preferred, and those wherein k is 1 or 2 are preferred.

  The sulfonic acid group simultaneously contained in the polymer composition is a sulfonic acid group bonded to the main chain through a linking group as shown in the following general formula III, and the sulfonic acid group is neutralized by an arbitrary base. And those in the form of salts are preferred.

  In the above general formula III, the linking group L represents any atom or group that connects the main chain and the sulfonic acid group, and is preferably an alkylene group, an arylene group, or the like. Examples of the base B that forms a salt with a sulfonic acid group include inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide, various amines, and quaternary compounds such as tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and choline. An ammonium base or the like is preferably used.

  There is a preferred range for the ratio of the phenyl group to which a cationic group or a sulfonic acid group and a vinyl group are bonded in the polymer composition contained in the photosensitive layer. The repeating unit having a cationic group or a sulfonic acid group is preferably in the range of 40% by mass to 90% by mass in the polymer composition. When the content is less than this, the polymer becomes insoluble in water, and the water developing or printing machine is used. The above development may not be possible. On the other hand, when the content is 90% by mass or more, the photocurability is insufficient and sufficient printing durability may not be obtained.

  There is a more preferred base as a base for neutralizing the sulfonic acid group. It is a tertiary amine having a hydroxyl group, and specific examples include dimethylaminoethanol, diethylaminoethanol, triethanolamine, n-butyldiethanolamine, and t-butyldiethanolamine. By using a polymer obtained by neutralizing the sulfonic acid group using these bases, the water developability or on-press developability of the polymer becomes very good, which is extremely preferable for preventing the occurrence of background stains.

  There is a preferred range for the molecular weight of the polymer, and the weight average molecular weight is preferably in the range of 5000 to 200,000. If the molecular weight is less than this, the printing durability is unsatisfactory, and the molecular weight exceeding 200,000 is applied. In some cases, the viscosity of the coating liquid becomes too high, making uniform coating difficult. The most preferred molecular weight range is between tens of thousands and 100,000.

  In the polymer composition, various repeating units can be introduced in addition to the above repeating units having a cationic group or a sulfonic acid group and a vinyl group depending on the purpose. For example, as a hydrophilic monomer, acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid, maleic acid monoalkyl ester, fumaric acid monoalkyl Carboxyl group-containing monomers such as esters, 4-carboxystyrene, acrylamide-N-glycolic acid and salts thereof, phosphate group-containing monomers such as vinylphosphonic acid and salts thereof, allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylate Amino group-containing monomers such as 4-aminostyrene, 4-aminomethylstyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-vinylbenzyl) amine And quaternary ammonium salts thereof, nitrogen-containing heterocycle-containing monomers such as 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole and N-vinylcarbazole, and quaternary ammonium salts thereof, acrylamide, methacrylamide, N, (Meth) acrylamides such as N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N-isopropylmethacrylamide, diacetoneacrylamide, N-methylolacrylamide, 4-hydroxyphenylacrylamide, 2- Hydroxyethyla Relate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, hydroxyalkyl (meth) acrylates such as glycerol monomethacrylate, methacrylic acid methoxydiethylene glycol monoester, methacrylic acid methoxypolyethylene glycol monoester, methacrylic acid Examples include, but are not limited to, alkyleneoxy group-containing (meth) acrylates such as polypropylene glycol monoester, N-vinylpyrrolidone, and N-vinylcaprolactam. These water-soluble monomers may be used alone or in combination of any two or more.

  Alternatively, as a hydrophobic monomer, styrene derivatives such as styrene, 4-methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-chloromethylstyrene, 4-methoxystyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate , N-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate, alkyl (meth) acrylates such as dodecyl methacrylate, aryl (meth) acrylates such as phenyl methacrylate, benzyl methacrylate, or arylalkyl (meth) acrylates , Acrylonitrile, methacrylonitrile, phenylmaleimide, hydroxyphenylmaleimide, vinyl acetate, chlorovinegar Vinyl esters such as vinyl, vinyl propionate, vinyl butyrate, vinyl stearate and vinyl benzoate, vinyl ethers such as methyl vinyl ether and butyl vinyl ether, acryloylmorpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol And various monomers such as vinyltrimethoxysilane and glycidyl methacrylate. A copolymer composed of any combination thereof and containing the sulfonic acid group and the vinyl group in the repeating unit at the same time can be used as the polymer in the present invention. When such a repeating unit other than the sulfonic acid group and vinyl group is contained in the polymer, the proportion in the polymer is preferably limited to 50% by mass or less of the whole, and when introduced in a proportion higher than this, Is not preferable because it may hinder both the prevention of soiling and the printing durability, which are the object of the present invention.

  Examples of preferred polymers in the present invention are shown below, but are not limited to these examples. In the formula, the number represents the mass% of each repeating unit in the polymer.

  The photocurable photosensitive layer according to the present invention contains a photopolymerization initiator together with the polymer. 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 photopolymerization initiators that can be used in the present invention include (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, e) ketoxime ester compounds, (f) azinium compounds, (g) active ester compounds, (h) metallocene compounds, (i) trihaloalkyl-substituted compounds, and (j) organoboron compounds.

  (A) Preferred examples of aromatic ketones include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” J.P.FOUASSIER, J.F.RABEK (1993), p. 77-P. 177, a compound having a benzophenone skeleton or a thioxanthone skeleton, an α-thiobenzophenone compound described in Japanese Patent Publication No. 47-6416, a benzoin ether compound described in Japanese Patent Publication No. 47-3981, and Japanese Patent Publication No. 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, JP-A A thio-substituted aromatic ketone described in JP-A-61-194062, The acylphosphine sulfide described in JP-B-2-9597, the acylphosphine described in JP-B-2-9596, the thioxanthone described in JP-B-63-61950, and described in JP-B-59-42864 Of coumarins.

  (B) Examples of aromatic onium salts include N, P, As, Sb, Bi, O, S, Se, Te, or I aromatic onium salts. Examples of such aromatic onium salts include compounds exemplified in JP-B Nos. 52-14277, 52-14278, and 52-14279.

  (C) Examples of the organic peroxide 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 ′ -Peroxide esters such as tetra (p-isopropylcumylperoxycarbonyl) benzophenone and di-tert-butyldiperoxyisophthalate are preferred. Arbitrariness.

  (D) Examples of hexaarylbiimidazole include lophine dimers described in JP-B Nos. 45-37377 and 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) -4,4 ′, 5 Examples include 5′-tetraphenylbiimidazole.

  (E) Examples of ketoxime esters include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentane- 3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3-p-toluenesulfonyloxyiminobutan-2-one, 2- And ethoxycarbonyloxyimino-1-phenylpropan-1-one.

  (F) Examples of azinium salt compounds are described in JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, JP-B-46-42363, etc. And a group of compounds having the N—O bond.

  (G) Examples of active ester compounds include imide sulfonate compounds described in JP-B-62-2223, etc., and active sulfonates described in JP-B-63-14340, JP-A-59-174831, etc. Can do.

  (H) Examples of metallocene compounds include those described in JP-A Nos. 59-152396, 61-151197, 63-41484, 2-249, and 2-4705. Examples thereof include titanocene compounds and iron-arene complexes described in JP-A-1-304453 and JP-A-1-152109. Specific titanocene compounds include, for example, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3. , 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti -Bis-2,4,6-trifluorophen-1-yl, dicyclopentadienyl-Ti-2,6-di-fluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2 , 4-di-fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl- Examples include i-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3- (pyr-1-yl) -phen-1-yl, and the like. be able to.

  (I) Specific examples of the trihaloalkyl-substituted compound include compounds having at least one trihaloalkyl group such as a trichloromethyl group and a tribromomethyl group in the molecule. US Pat. No. 3,954,475 No. 3,987,037, No. 4,189,323, JP-A Nos. 61-151644, 63-298339, No. 4-69661, No. 11-15359, etc. Trihalomethyl-s-triazine compounds described in JP-A Nos. 54-74728, 55-77742, 60-138539, 61-143748, 4-362644, 11-11 And 2-trihalomethyl-1,3,4-oxadiazole derivatives described in Japanese Patent No. 84649. Moreover, the trihaloalkylsulfonyl 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.

  (J) Examples of the organic boron salt compound are described in JP-A-8-217813, JP-A-9-106242, JP-A-9-188865, JP-A-9-188686, JP-A-9-188710, and the like. Organic boron ammonium compounds, organic boron sulfonium compounds and organic boron oxosulfonium compounds described in JP-A-6-175561, JP-A-6-175564, JP-A-6-157623, etc., JP-A-6-175553, Organoboron iodonium compounds described in JP-A-6-175554, etc., organoboron phosphonium compounds described in JP-A-9-188710, etc., JP-A-6-348011, JP-A-7-128785, JP-A-7-140589. No. 7, 7-292014, 7-306527, etc. Coordination complex compounds. Moreover, cationic dyes containing an organic boron anion as the counter anion described in JP-A-62-143044 and JP-A-5-194619 can be mentioned.

  In addition, when the photocurable photosensitive layer of the present invention is adapted to ultraviolet light near 405 nm, (d) hexaarylbiimidazole, (h) metallocene compound, (i) trihaloalkyl-substituted compound, (j) organic Boron salt compounds are particularly preferred.

  Moreover, when making the photocurable photosensitive layer of this invention respond | correspond to near-infrared-infrared light of 750 nm or more, (i) a trihaloalkyl substituted compound and (j) an organic boron salt compound are especially preferable.

  The above photopolymerization initiators may be used alone or in any combination of two or more. In particular, it is preferable to use a combination of (i) a trihaloalkyl-substituted compound and (j) an organic boron salt compound because the sensitivity is greatly improved. The content of the photopolymerization initiator in the photocurable photosensitive layer is preferably in the range of 1 to 100% by mass and more preferably in the range of 1 to 40% by mass with respect to the water-soluble polymer.

  For the photopolymerization initiator related to the present invention, an organic boron salt is particularly preferably used. More preferably, an organic boron salt and a trihaloalkyl-substituted compound (for example, an s-triazine compound, an oxadiazole derivative or a trihaloalkylsulfonyl compound as a trihaloalkyl-substituted nitrogen-containing heterocyclic compound) are used in combination.

  The organoboron anion constituting the organoboron salt is represented by the following general formula IV.

In the formula, R ₅ , R ₆ , R ₇ and R ₈ may be the same or different and each represents an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group or heterocyclic group. To express. Of these, it is particularly preferred that one of R ₅ , R ₆ , R ₇ and R ₈ 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. 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 IV shown above, and alkali metal ions and onium compounds are preferably used as cations forming the salt. 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. 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 examples of trihaloalkyl-substituted nitrogen-containing heterocyclic compounds and trihaloalkylsulfonyl compounds are shown below.

  In the photocurable photosensitive layer according to the present invention, a compound having a sensitivity peak in the vicinity of 400 to 430 nm or 750 to 1100 nm, having absorption in this wavelength region, and sensitizing the above-mentioned photopolymerization initiator. It is preferable to contain it together. Examples of the compound capable of increasing the sensitivity in the vicinity of 400 to 430 nm include carbazole compounds described in JP-A-9-230913 and JP-A-2001-42524, JP-A-8-262715, and JP-A-8-272096. Carbomerocyanine dyes described in JP-A-9-328505, JP-A-4-194857, JP-A-6-295061, JP-A-7-84863, JP-A-8-220755, JP-A-9-80750. Aminobenzylidene ketone dyes described in JP-A-9-236913, JP-A-4-184344, JP-A-6-301208, JP-A-7-271284, JP-A-8-29973, etc. Coumarin dyes, JP-A-7-225474, JP-A-7-5585, JP-A-7-281434, JP-A-8-62 No. 5 Piromechin dyes described, for example, in JP, various sensitizers may be a preferably used, such as styryl dyes described, for example, in JP-A-9-80751 JP. In combination with the organic boron salt, a pyrylium compound or a thiopyrylium compound is particularly preferable.

  As sensitizing dyes at 750 to 1100 nm, cyanine, phthalocyanine, merocyanine, coumarin, porphyrin, spiro compound, ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, phenothiazine, polyene, azo compound, diphenylmethane, triphenylmethane, polymethine acridine, Examples include coumarin, ketocoumarin, quinacridone, indigo, styryl, squarylium compound, and pyrylium compound, and further described in European Patent No. 0,568,993, US Patent Nos. 4,508,811, and 5,227,227. These compounds can also be used.

  Although the specific example of the sensitizing dye which can be used preferably is shown below, this invention is not limited to these. Sensitizing dyes corresponding to ultraviolet light in the vicinity of 400 to 430 nm are shown below.

  Sensitizing dyes corresponding to near infrared light in the vicinity of 750 to 1100 nm are shown below.

  In the present invention, the photopolymerizable composition may contain a polyfunctional monomer as a compound having a polymerizable double bond in the molecule, in addition to a polymer having a polymerizable double bond in the side chain. Examples of such polyfunctional monomers include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene glycol. Polyfunctional (acrylic) monomers such as diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, or various polymers having acryloyl group or methacryloyl group introduced as polyester (meth) acrylate, urethane (meta ) Acrylates, epoxy (meth) acrylates and the like are used in the same manner.

  In addition, as an element constituting the photocurable photosensitive layer, various kinds of dyes and pigments are added for the purpose of enhancing the visibility of images, and inorganic fine particles or organic fine particles are used for the purpose of preventing blocking of the photosensitive composition. It is also preferably carried out.

  In order to prevent the curing reaction in the dark due to thermal polymerization, a polymerization inhibitor is preferably added to the photocurable photosensitive layer for long-term storage. As the polymerization inhibitor preferably used for such purposes, various known phenol compounds can be used.

  Regarding the thickness of the photosensitive layer itself when used as a lithographic printing plate material, it is preferably formed on the hydrophilic layer with a dry thickness in the range of 0.5 μm to 10 μm, and more preferably in the range of 0.6 μm to 3 μm. Is extremely preferable for exhibiting good resolution and greatly improving printing durability. For the photosensitive layer, a solution in which the above-described various elements are mixed is prepared, and is coated on the hydrophilic layer and dried using various known coating methods.

  In order to use a material having a photocurable photosensitive layer and a hydrophilic layer formed on a support having a specific undercoat layer as described above as a printing plate, adhesion exposure or laser scanning exposure is applied thereto. Since the solubility in water is reduced by crosslinking the exposed portion, pattern formation is performed by eluting the unexposed portion with water.

  In the present invention, the water used for water development may include pure water or various inorganic and organic ionic compounds, or water containing sodium, potassium, calcium, magnesium ions, or the like. good. Moreover, when using dampening water for on-press development on a printing press, various commercially available dampening water can be used, and it is preferable to use pH within the range of about 4-10. Further, water may contain solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, methoxyethanol, and polyethylene glycol as various alcohols. Alternatively, development using various commercially available gum solutions can also be preferably used for the purpose of protecting the plate surface from fingerprint stains and the like.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples. In addition, the number of parts and percentage in an Example are based on mass.

(Example 1 and Comparative Examples 1-3)
Various lithographic printing plate supports having different undercoat layers were evaluated.

(Undercoat layer used in Examples)
Asahi Kasei Kogyo Co., Ltd. as a self-emulsifiable isocyanate compound in a solution obtained by diluting a water-dispersed polyurethane emulsion (Permarin UA-310, manufactured by Sanyo Chemical Industries, Ltd.) to a solid content concentration of 10% on a polyester film having a thickness of 100 μm. A solution obtained by adding a compound obtained as deuranate WB40-80 to 20% of the solid content of the polyurethane emulsion was applied to form an undercoat layer having a dry thickness of 0.5 μm. The undercoat layer was subjected to evaluation after coating and drying, followed by heating in a dryer at 40 ° C. for 24 hours.

(Undercoat layer used in Comparative Example 1)
On the same 100 μm thick polyester film as described above, a solution of vinylidene chloride latex (manufactured by Asahi Kasei Kogyo Co., Ltd., L536B, vinylidene chloride ratio 90% or more, hydroxyl group-modified latex) was applied to form an undercoat layer having a dry thickness of 0.5 μm. The undercoat layer was subjected to evaluation after coating and drying, followed by heating in a dryer at 40 ° C. for 24 hours.

(Undercoat layer used in Comparative Example 2)
A terpolymer copolymer latex (Tg = 75 ° C.) solution of styrene / glycidyl methacrylate / butyl acrylate = 60/39/1 is applied on a polyester film having a thickness of 100 μm as described above, and a dry thickness of 0.5 μm is subtracted. A layer was formed. The undercoat layer was subjected to evaluation after coating and drying, followed by heating in a dryer at 40 ° C. for 24 hours.

(Undercoat layer used in Comparative Example 3)
A water-dispersible polyester resin (Pesresin A-515G, manufactured by Takamatsu Yushi Co., Ltd.) solution was applied on the same 100 μm thick polyester film as above to form an undercoat layer having a dry thickness of 0.5 μm. The undercoat layer was subjected to evaluation after coating and drying, followed by heating in a dryer at 40 ° C. for 24 hours.

(Hydrophilic layer)
Using the polyester film having the above various undercoat layers, a hydrophilic layer represented by the following formulation is formed thereon, and the corresponding lithographic printing plate supports of Example 1 and Comparative Examples 1 to 3 are obtained. It was. The hydrophilic layer was applied using a wire bar so that the dry weight was 2 g per square meter. Drying was performed by heating for 20 minutes with a dryer at 80 ° C. The sample was further heated in a dryer at 40 ° C. for 3 days.

(Hydrophilic layer coating formulation)
10 g of water-soluble polymer (A-5 in chemical formula 3) solution (10% concentration)
Colloidal silica (Snowtex PS-M manufactured by Nissan Chemical Industries, Ltd.) (20% solution)
10g
Epoxy crosslinking agent (E-3 in chemical formula 4) 0.2 g
10g of pure water

(Adhesion evaluation)
About the lithographic printing plate support of Example 1 and Comparative Examples 1 to 3 prepared above, the adhesion of the hydrophilic layer to the plastic film substrate was evaluated as follows. As a water resistance test, each support was immersed in water kept at 30 ° C. for 24 hours, taken out, and rubbed strongly with a sponge to examine whether the hydrophilic layer was peeled off. The case where it did not exfoliate was set as (circle), and the case where it peeled even a little was set as x. As an alkali resistance test, it was similarly immersed in a 0.1 N aqueous sodium hydroxide solution for 24 hours, taken out, and rubbed strongly with a sponge under running water to examine whether the hydrophilic layer was peeled off. The case where it did not exfoliate was set as (circle), and the case where it peeled even a little was set as x. As a solvent resistance test, dimethylformamide was used, soaked in this solvent for 1 hour, taken out, and rubbed strongly with a sponge under running water to examine whether the hydrophilic layer was peeled off. The case where it did not exfoliate was set as (circle), and the case where it peeled even a little was set as x. As a tape adhesion test, a 5 mm square grid-like scratch was attached to the surface of the hydrophilic layer side of the support with a cutter knife, and when the cellophane (registered trademark) was adhered, it was peeled off at once. The case where peeling occurred was rated as x, and the case where peeling was not observed was marked as o. The evaluation results are summarized in Table 1. The support obtained in Example 1 showed good results in all items.

(Example 2 and Comparative Examples 4 to 6)
Evaluation was performed on a lithographic printing plate using a photocurable photosensitive layer. Using the support obtained in Example 1, the photosensitive layer shown below was provided on the support to prepare a photosensitive lithographic printing plate material of Example 2. Further, the same photosensitive layer was provided on the support prepared in Comparative Examples 1 to 3 to prepare photosensitive lithographic printing plate materials of Comparative Examples 4 to 6, respectively.

(Photo-curable photosensitive layer)
On the lithographic printing plate support, a coating solution having the following formulation was applied to form a photocurable photosensitive layer. The photocurable photosensitive layer was applied using a wire bar so that the dry weight was 1 g per square meter. Drying was performed by heating for 10 minutes with a dryer at 80 ° C.

(Photocurable photosensitive layer coating formulation)
Polymer (SP-8) solution (25% concentration) 4g
Photopolymerization initiator (BC-6) 0.1g
Photopolymerization initiator (T-2) 0.05g
Sensitizing dye (S-38) 0.03g
Victoria Blue (coloring dye) 0.02g
Dioxane 9g
1g of ethanol

(Exposure test)
The photosensitive lithographic printing plate material provided with the photosensitive layer on the lithographic printing plate support produced as described above was subjected to an exposure test as follows. The exposure is carried out using a PT-R4000 (manufactured by Dainippon Screen Mfg. Co., Ltd.) equipped with an 830 nm laser used for an aluminum printing plate, and in order to perform drawing using this apparatus, the above is performed on a 0.24 mm aluminum plate. These samples were laminated using a double-sided tape so that the photosensitive layer was on the surface. The exposure energy was set to be about 50 mJ / cm ² on the film surface, and drawing was performed at a drum rotation speed of 1000 rpm. As a test image, a halftone dot pattern corresponding to 2400 dpi and 175 lines and a 10 to 100 μm thin line were output, and the resolution evaluation described later was performed.

(Printability test)
Ryobi 560 offset sheet-fed printing press is used as the printing machine, Daikoku Ink Chemical Industries' Dicure High Bright (ultraviolet curable UV ink) ink is used as the printing ink, and the fountain solution is a commercially available PS. The plate moistening liquid Toho Etch was diluted to 1% and used. The number of printed sheets was up to 40,000, and printing evaluation items were evaluated using the number of printed sheets until the minute halftone dots and fine lines in the test image started to disappear. The reason for using the ultraviolet curable UV ink in the evaluation is due to the background that printing durability against such UV ink is often poor and improvement in printing durability is required. Water retention was evaluated as ◯ when there was no scumming through printing, △ when scumming occurred in the initial or later stage of printing, and x when scumming was recognized throughout.

  The results of evaluation as described above are summarized in Table 2.

  As can be seen from Table 2, in Example 2, there were no problems with 40,000 printed materials. However, in any comparative example, the printing durability was at most about 20,000 sheets, and the difference in the support. It was a result.

(Examples 3-5 and Comparative Examples 7-10)
In the following hydrophilic layer coating liquid formulation, a support was similarly prepared and tested by changing the presence or absence of a crosslinking agent and the ratio of colloidal silica and water-soluble polymer. The hydrophilic layer was applied using a wire bar so that the dry weight was 2 g per square meter. Drying was performed by heating for 20 minutes with a dryer at 80 ° C.
(Hydrophilic layer coating formulation)
Water-soluble polymer (S-1) solution (10% concentration) In Table 3, X (g)
Colloidal silica (Snowtex 20 manufactured by Nissan Chemical Industries, Ltd.)
(20% solution) In Table 3, Y (g)
Cross-linking agents Table 3
10g of pure water

  Table 4 shows the results of the adhesion evaluation performed in the same manner as in Example 1. Examples 3 to 5 all gave good results, but Comparative Examples 7 to 10 all had poor adhesion.

  Furthermore, using the supports prepared in Examples 3 to 5 and Comparative Examples 7 to 10, the photocurable photosensitive layer coating liquid used in Example 2 was applied onto the support and dried, thereby photosensitive lithographic printing. A plate material was prepared. Exposure and printing tests were performed in the same manner as in Example 2, and the results shown in Table 5 were obtained.

(Examples 6-8 and Comparative Examples 11-14)
A test was conducted on the production of a lithographic printing plate using an ink jet recording system.

  An ink image was formed in an image-like manner on the lithographic printing plate support produced in Examples 3 to 5 using a commercially available inkjet printer, and Examples 6 to 8 were obtained. As a comparison, an ink image was formed in an image-like manner on the lithographic printing plate support produced in Comparative Examples 7 to 10 to be Comparative Examples 11 to 14. As the ink, an ink having a composition of 100 parts by mass of ethylene glycol dimethacrylate and 5 parts by mass of diethoxyacetophenone was used. From the formed ink image, a 5 kW xenon lamp was irradiated for 5 minutes from a distance of 20 cm to cure the ink image to form an image layer. As a result, a lithographic printing plate was obtained. A printability test was performed in the same manner as in Example 2, and the results shown in Table 6 were obtained.

Example 9
A test was conducted on a method for producing a lithographic printing plate using a thermal transfer system.

(Hydrophilic layer)
Using a 100 μm thick polyester film having an undercoat layer of Example 1, a hydrophilic layer represented by the following formulation was formed thereon to obtain a lithographic printing plate support. The hydrophilic layer was applied using a wire bar so that the dry weight was 2 g per square meter. Drying was performed by heating for 20 minutes with a dryer at 80 ° C.

(Hydrophilic layer coating formulation)
20 g of water-soluble polymer (A-5 in chemical formula 2) solution (10% concentration)
Colloidal silica (Snowtex PS-MO manufactured by Nissan Chemical Industries, Ltd.)
(20% solution) 10g
Cross-linking agent (E-4 in chemical formula 4) 0.2 g
10g of pure water

  A heat-sensitive transfer layer composed of an ethylene / vinyl acetate copolymer and carbon black was formed on one surface of a polyester film having a thickness of 3 μm with a layer thickness of 2 μm to obtain a heat-sensitive transfer sheet. Next, the image forming substrate and the thermal transfer sheet are stacked so that the hydrophilic layer and the thermal transfer layer of the thermal transfer sheet are in close contact with each other, are attached to the thermal printer, the printer is operated, and the thermal head is operated. The heat-sensitive transfer sheet was partially heated, and the heat-sensitive transfer layer was transferred onto the lithographic printing plate support to form an image-like lipophilic layer. As a result, a lithographic printing plate was obtained. A printability test was conducted in the same manner as in Example 2, and 40,000 sheets of good printing durability and good water retention were obtained in the same manner.

    According to the present invention, since a plastic sheet having a hydrophilic surface with a film as a support is provided, it can be used as various printing plates and printing sheets. It can also be used as an ink jet recording medium or a thermal recording medium.

Claims (6)

  It has an undercoat layer containing a self-emulsifiable isocyanate and a water-dispersible polyurethane resin on a plastic film substrate, and further contains a water-soluble polymer and colloidal silica in a mass ratio of 3: 1 to 1: 5. A lithographic printing plate support having a hydrophilic layer.   The lithographic printing plate support according to claim 1, wherein the hydrophilic layer contains a crosslinking agent for crosslinking the water-soluble polymer. The lithographic printing plate support according to claim 1 or 2, wherein the water-soluble polymer is a polymer represented by the following general formula I.

(In the above formula, X represents mass% of the repeating unit in the copolymer composition, and represents any numerical value from 1 to 40. The repeating unit A has a carboxyl group or an amino group as a reactive group. (Repeating unit B represents repeating unit having a hydrophilic group necessary for making the copolymer water-soluble)   A method for producing a lithographic printing plate, comprising: depositing an image-forming material imagewise on the lithographic printing plate support according to claim 1 by an inkjet method to form an oleophilic image layer on a part of the surface of the hydrophilic layer. .   The thermal transfer layer of the thermal transfer sheet having the thermal transfer layer on the sheet is adhered to the surface of the hydrophilic layer of the lithographic printing plate support according to claim 1, and then a thermal head or A method for producing a lithographic printing plate, wherein a thermal transfer layer corresponding to the heated portion is transferred onto the hydrophilic layer by imagewise heating with laser light to form an oleophilic image layer.   A photosensitive lithographic printing plate material comprising a photocurable photosensitive layer provided on the surface of the hydrophilic layer of the lithographic printing plate support according to claim 1.