JP2014224845A - Photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate in which an image part having sufficient printing durability can be formed without decreasing development stability.SOLUTION: The photosensitive lithographic printing plate includes a hydrophilic layer and a photopolymerizable photosensitive layer, at least in this order on an aluminum support, various plastic film supports, a paper support laminated with various plastics, or the like; and more particularly, chemical-less development can be performed on the photosensitive lithographic printing plate. The hydrophilic layer comprises a gelatin binder and inorganic fine particles treated with a silane coupling agent having a primary amino group.

Description

  The present invention relates to a photosensitive lithographic printing plate having at least a hydrophilic layer and a photopolymerizable photosensitive layer in this order on a support, and more particularly to a photosensitive lithographic printing plate capable of chemicalless development.

  In recent years, computer-to-plate (CTP) technology that directly outputs digital data formatted on a computer screen to a lithographic printing plate has been developed along with the digitization of the plate making system, and various plates equipped with various lasers as output machines. The development of setters and photosensitive lithographic printing plates compatible with these is being actively pursued. As such an output machine, an output machine using various lasers such as a blue-violet semiconductor laser (violet laser), a helium neon laser, a red LED, a near infrared laser, an infrared laser, and an argon laser is preferably used.

  As a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer corresponding to such various lasers, for example, JP-A-9-134007 discloses a radically polymerizable compound having an ethylenically unsaturated bond and photosensitization. A photosensitive lithographic printing plate containing a dye and a polymerization initiator is disclosed. JP-A-5-5988, JP-A-5-194619, JP-A-2000-98603 and the like disclose an organic boron anion and Combinations with pigments are disclosed, and JP-A-4-31863, JP-A-6-43633, etc. disclose combinations of pigments with s-triazine compounds, and JP-A-7-20629. JP-A-7-271029 discloses a combination of a resole resin, a novolac resin, an infrared absorber and a photoacid generator. No. -21252, JP-A-11-231535, etc. disclose a combination of a specific polymer, a photoacid generator and a near-infrared sensitizing dye. A photosensitive lithographic printing plate using a polymer having a phenyl group substituted with a vinyl group in the chain is disclosed. JP-A-2005-274695 and JP-A-2007-25220 disclose photosensitive lithographic printing plates having a photopolymerizable photosensitive layer corresponding to a violet laser light source.

  On the other hand, as an important problem or demand that has been highlighted with the spread of the CTP method, there are various points related to development processing. In normal CTP, a photosensitive lithographic printing plate is exposed to a laser image, and then a non-image area is eluted with a developer containing a strong alkali agent, and is subjected to printing through a water washing and gumming process. However, such an alkaline developer is harmful to the human body, and sufficient care and management are required for its handling and storage. In addition, the purchase cost and the cost related to waste liquid treatment impose a great burden on the user. In addition, the pH and temperature of the alkaline developer must be managed with great care. Handling is complicated and it is always difficult to obtain reproducible results in the plate making process.

  There has been proposed a photosensitive composition that avoids the use of such an alkaline developer and can be developed with water or the like. For example, in Japanese Patent Laid-Open No. 5-27437 (Patent Document 1), an aqueous photosensitive composition containing a carboxyl group-containing resin, an amine compound, a photopolymerizable unsaturated compound, a photopolymerization initiator and water is used for the production of printed circuits. Use is disclosed. JP-A 2003-215801 (Patent Document 2) uses a photosensitive composition using an anionic water-soluble polymer having a polymerizable double bond group in the side chain as a binder polymer for a photosensitive lithographic printing plate. Is disclosed. However, when the above-described photosensitive composition is developed with water using an automatic developing machine, the generation of sludge that accumulates in the water developer becomes significant, and when the sludge re-adheres to the non-image area, printing is performed. In some cases, the image may become smudged, and if it adheres again to the image area, the image may be lost during printing, and improvement in development stability has been demanded.

  As a method for solving the above-mentioned problem, for example, JP 2011-209354 A (Patent Document 3) discloses an underwater emulsion in which a photopolymerization initiator and a compound having a polymerizable double bond group are emulsified and dispersed in water. A method of use is disclosed, and in the emulsion in water, a photopolymerization initiator is contained in the dispersed phase. In such a system, the problem of smudges during printing when developing with water or the like using the automatic processor described above has been solved, but the printing durability is still insufficient depending on the printing conditions, and micro-images are missing. May occur or the ink density in the image area may decrease during printing, and improvements have been demanded.

  On the other hand, as a technology capable of achieving both hydrophilicity capable of avoiding ink stains in non-image areas and printing durability, Japanese Patent Application Laid-Open No. 2008-265297 (Patent Document 4) discloses a water-soluble polymer on a support. A photosensitive lithographic printing plate containing a cross-linking agent that crosslinks the water-soluble polymer and colloidal silica and having a hydrophilic layer in which the ratio of the water-soluble polymer and colloidal silica is specified is disclosed, and further, JP 2009-226596 A (Patent Document 5) discloses a photosensitive lithographic printing plate in which the hydrophilic layer contains at least a water-soluble polymer and inorganic fine particles, and the film surface pH value of the hydrophilic layer is 7.0 or more. In addition, as a lithographic printing plate containing a water-soluble resin in a hydrophilic layer, Japanese Patent Application Laid-Open No. 2005-3503 (Patent Document 6) discloses inorganic fine particles such as metal oxide fine particles and colloidal silica in a hydrophilic layer serving as a non-image portion. And a lithographic printing plate containing a water-soluble resin such as a polysaccharide. JP-A-2006-306031 (Patent Document 7) discloses a lithographic printing plate in which a water-soluble polymer and an alkoxide compound are coated on a support. Is disclosed.

JP-A-5-27437 JP 2003-215801 A JP 2011-209354 A JP 2008-265297 A JP 2009-226596 A Japanese Patent Laying-Open No. 2005-3503 JP 2006-306031 A

  An object of the present invention is to provide a photosensitive lithographic printing plate capable of forming an image portion capable of obtaining sufficient printing durability without deteriorating development processing stability.

  A photosensitive lithographic printing plate having at least a hydrophilic layer and a photopolymerizable photosensitive layer in this order on a support, wherein the hydrophilic layer is treated with a gelatin binder and a silane coupling agent having a primary amino group. A photosensitive lithographic printing plate comprising inorganic fine particles.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive lithographic printing plate in which the image part which can obtain sufficient printing durability without reducing development processing stability can be provided can be provided.

1 is an example of a plate making apparatus for developing the photosensitive lithographic printing plate of the present invention.

  The present invention will be described in detail below.

  Examples of the support of the photosensitive lithographic printing plate of the present invention include an aluminum support, various plastic film supports, and a paper support laminated with various plastics. Among them, a plastic film support which is a material having flexibility and less deformation due to tension and a paper support laminated with various plastics are preferably used. Preferred plastic film supports include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose nitrate, polyolefin resin-coated paper, etc. Typical examples include polyethylene terephthalate and polyethylene naphthalate.

  The surface of these supports may be subjected to a surface treatment in order to improve adhesion with a hydrophilic layer or a backing layer provided as necessary. Examples of such surface treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. As a further surface treatment, an undercoat layer may be provided on the support in order to enhance adhesion with the hydrophilic layer provided on the support.

  The hydrophilic layer of the photosensitive lithographic printing plate of the present invention contains inorganic fine particles treated with a gelatin binder and a silane coupling agent having a primary amino group.

  In the hydrophilic layer of the present invention, gelatin is used as a binder polymer. By using gelatin, it is possible to obtain a hydrophilic layer having sufficient film strength that can withstand printing because the bonding between inorganic fine particles becomes strong while maintaining high hydrophilicity.

  The gelatin used in the present invention is a kind of derived protein, and is not particularly limited as long as it is called gelatin produced from collagen. Preferably, it shows a pale, transparent, tasteless and odorless appearance. Further, gelatin for photographic emulsions is more preferable because physical properties such as viscosity and gel jelly strength in an aqueous solution are within a certain range.

  The hydrophilic layer of the present invention preferably contains a gelatin crosslinking agent.

  A conventionally known compound can be used as a crosslinking agent for gelatin. For example, formaldehyde, N-methylol compounds (for example, N-methylol urea, N-methylol melamine, N-methylol ethylene urea, and initial condensates thereof), dialdehydes (for example, glyoxal, glutaraldehyde, succinaldehyde, etc.), various types Epoxy compounds (eg glycerol polyglycidyl ether, sorbitol polyglycidyl ether), activated vinyl compounds (eg bis (vinylsulfonyl) methane, bis (vinylsulfonylmethyl) ether), quinones (eg p-quinone), s- Examples include triazine (such as 2,4-dichloro-6-hydroxy-s-triazine). Among these, an activated vinyl compound is preferable, and among them, a crosslinking agent having at least two vinylsulfonyl groups in the molecule is particularly preferable.

  The crosslinking agent for gelatin is preferably 0.5 to 30% by mass with respect to the solid content of gelatin. More preferably, it is 0.8-20 mass%.

  In order to sufficiently crosslink the gelatin in the hydrophilic layer, for example, under the conditions of 30 to 60 ° C., preferably 40 to 50 ° C., between the formation of the hydrophilic layer and the application of the photopolymerizable photosensitive layer. It is preferable to apply a heating treatment for 0.5 to 10 days, preferably 1 to 7 days. Such a heating process exposes the hydrophilic layer by a development process after exposure, and even if it is subjected to printing as a non-image part at the time of printing, it is natural that printability is sufficient, but also from the viewpoint of scratch resistance. Performance can be realized.

  The hydrophilic layer of the present invention may contain a hydrophilic polymer other than gelatin. Examples of hydrophilic polymers other than gelatin include those obtained from algae such as starches, seaweed mannan, agar and sodium alginate, mannan, pectin, tragacanth gum, caraya gum, xanthine gum, guarbin gum, locust bin gum, gum arabic Plant mucilage such as dextran, glucan, xanthan gum, homopolysaccharide such as levan, microbial mucilage such as succinoglucan, pullulan, curdlan and heteropolysaccharide such as xanthan gum, protein such as casein and collagen, chitin And derivatives thereof. Semi-natural products (semi-synthetic products) include cellulose derivatives, modified gums such as carboxymethyl guar gum, cultured starches such as dextrin, processed starches such as oxidized starches and esterified starches. . On the other hand, as synthetic products, polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl isobutyl ether, polyacrylate, polyacrylate Acrylic ester partial saponification products, polymethacrylic acid salts, polyacrylic acid derivatives such as polyacrylamide and polymethacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer Styrene / maleic acid copolymer, styrene / crotonic acid copolymer, and the like.

  The content of the hydrophilic polymer other than gelatin is preferably 20% by mass or less, more preferably 10% by mass or less, based on the solid content of gelatin.

  The content of the hydrophilic binder in the hydrophilic layer (content of the hydrophilic binder including gelatin) has a preferable content ratio with respect to the sum of the inorganic fine particles described later, and is 5 to the total solid content of the inorganic fine particles. The content is preferably 50% by mass, more preferably 10 to 40% by mass. If it exceeds 50% by mass, the packing density of the inorganic fine particles is lowered and sufficient hydrophilicity cannot be imparted, and the soil resistance and the anti-glare property may be lowered. On the other hand, if it is less than 5% by mass, the handling property of the coating liquid may be lowered, or cracks may occur after the formation of the hydrophilic layer.

  The hydrophilic layer of the present invention contains inorganic fine particles treated with a silane coupling agent having a primary amino group. The silane coupling agent having a primary amino group in the present invention is a silane coupling agent having both a tri- or dialkoxysilane structure and a primary amino group structure. Examples of the silane coupling agent used in the present invention are shown below.

  3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropyltri-t-butoxysilane, 3- (2-aminoethylamino) propyltriethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethylamino) propyltris (2-methoxyethoxy) silane, 3-aminopropyldiethoxymethylsilane, N-methyl-3-aminopropyl Triethoxysilane.

  The inorganic fine particles to be treated with the silane coupling agent are preferably highly reactive with the silane coupling agent, and natural silica such as quartz, sand, and novaculite, synthetic silica such as wet method silica and silica aerogel, kaolin and mica. , Natural silicates such as talc, wollastonite, asbestos, synthetic silicates such as calcium silicate, aluminum silicate, alumina, hydrated alumina, aluminum hydroxide, titanium dioxide, potassium titanate, zircon oxide, boric acid Aluminum, zinc oxide, iron oxide, magnesium oxide, etc. can be mentioned. Moreover, even if it is a carbonate, sulfate or phosphate of an alkaline earth metal such as calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, calcium phosphate, etc. Those subjected to a surface treatment with alumina can be preferably used because of their reactivity with the silane coupling agent. Among these, titanium dioxide, aluminum hydroxide, and barium sulfate surface-treated with silica and alumina are preferable.

  The method of treating these inorganic fine particles with a silane coupling agent may be either a dry method or a wet method, but more preferably a wet method. That is, a method of adjusting the slurry by introducing inorganic fine particles into an aqueous solution to which the silane coupling agent has been added in advance, or a method of adding a silane coupling agent to a slurry in which inorganic fine particles are dispersed in water is preferable. The addition amount of the silane coupling agent can be arbitrarily selected. However, if the amount is too small, the effect cannot be sufficiently obtained. If the amount is too large, the inorganic fine particles tend to aggregate, so that the handling property of the hydrophilic layer coating liquid is lowered. Usually, it is preferable to add in the range of 0.01 to 2% by mass with respect to the solid content of the fine particles.

  The treatment time and temperature when treating the inorganic fine particles with the silane coupling agent depend on the type of silane coupling agent and inorganic fine particles used, but the treatment time is approximately 1 to 5 hours, and the treatment temperature is 20 to 70. It is preferable to carry out in the range of ° C. In addition, the inorganic fine particle slurry that has been treated with the silane coupling agent may be filtered to take out only the inorganic fine particles, but may be used as the hydrophilic layer coating liquid in the state of the slurry.

  Titanium dioxide preferably used as the inorganic fine particles to be treated with the silane coupling agent may be either a rutile type or an anatase type, and the production method may be either a sulfuric acid method or a chlorine method. You may use them individually or in mixture. Furthermore, from the viewpoint of dispersion stability and other functionalities, those subjected to surface treatment with silica or alumina may be used. Examples of commercially available titanium dioxide include SR-1, R-650, R-5N, R-7E, R-3L, A-110, and A-190 from Sakai Chemical Industry Co., Ltd. ) From Taipei R-580, R-930, A-100, A-220, CR-58, Titanium Industry Co., Ltd., Kronos KR-310, KR-380, KA-10, KA -20 etc., Teica Co., Ltd., Titanics JR-301, JR-600A, JR-800, JR-701 etc., DuPont Co., Ltd. Taipure R-900, R-931 etc. are mentioned.

  Aluminum hydroxide mixes bauxite, which is an ore containing alumina, with caustic soda or sodium aluminate solution, extracts the alumina component under high temperature and high pressure conditions, separates and removes red mud as a dissolution residue from the extract, A clarified sodium aluminate solution is obtained. Thereafter, seeds can be added to the solution to crystallize aluminum hydroxide, and the obtained aluminum hydroxide can be pulverized. Various grades of aluminum hydroxide are commercially available from Showa Denko Co., Ltd. as “Hijilite”, and any grade can be used in the present invention.

  As barium sulfate, it is preferable to use precipitated barium sulfate produced by adding a sulfate aqueous solution to a barium chlorine solution and chemically precipitating. The precipitated barium sulfate surface-treated with silica and alumina is commercially available from Sakai Chemical Industry Co., Ltd. as “Variace B-30 Series”, and various particle sizes are commercially available. Can do.

  The hydrophilic layer of the present invention may contain inorganic fine particles that have not been treated with a silane coupling agent having a primary amino group, but 100 mass with respect to the solid content of the inorganic fine particles treated by the above method. % Or less is preferable, and more preferably 50% by mass or less.

  The particle size distribution of the inorganic fine particles contained in the hydrophilic layer has peaks in at least two places of a range of 0.2 μm or more and less than 0.6 μm and a range of 0.6 μm or more and less than 1.5 μm. When the distribution frequency of the inorganic fine particles existing in the range of less than 6 μm is fx and the distribution frequency of the inorganic fine particles existing in the range of 0.6 μm or more and less than 1.5 μm is fy, the fx / fy ratio is 1.5 or more. The distribution frequency fy is preferably 25% or more. The fx / fy ratio is preferably 2.0 or more. The upper limit is desirably less than 3.5. As a result, a photosensitive lithographic printing plate having excellent printing durability and stain resistance can be obtained. In the above-mentioned range, for example, when a plurality of peaks are present in the range of 0.2 μm or more and less than 0.6 μm, the distribution frequency fx may be obtained with the higher peak. In the case where the height of the recess between two peaks is 60% or more of the higher peak, it is regarded as one peak in the present invention.

  The particle size distribution is a volume-based particle size distribution, which is an index indicating what kind of particle size the sample particle group to be measured is and what ratio is constituted by a generally known method. Can be measured. For example, a sieving method, a Coulter method (Coulter principle), a dynamic light scattering method, an image analysis method, a laser diffraction scattering method, etc. are known as the measuring method. In the present invention, the particle size to be measured and reproducibility are known. From the viewpoint of operability and the like, a laser diffraction / scattering method is preferably used. For example, it can be measured by LA-920 (laser diffraction / scattering type particle size distribution measuring apparatus) manufactured by Horiba, Ltd. The distribution frequency can be obtained as a distribution of the existence ratio for each size (particle diameter) based on the measurement result.

  The particle size distribution and distribution frequency can be determined by measuring the inorganic fine particles dispersed in the coating solution, or by measuring the inorganic fine particles in a solution in which the dried coating film of the applied hydrophilic layer is redissolved with alkali. Can be sought. As will be described later, in the present invention, two or more kinds of inorganic fine particles can be used in combination. However, in the laser diffraction scattering method preferably used in the present invention, the light intensity distribution pattern is obtained from the Fraunhofer diffraction theory and the Mie scattering theory. Therefore, a refractive index specific to the object is required, and it is difficult to accurately measure the particle size distribution and distribution frequency of a coating liquid containing two or more kinds of inorganic fine particles having different refractive indexes. However, in such a case, the particle size distribution and distribution frequency of each individual inorganic fine particle are measured in advance, and two or more kinds of inorganic fine particles are obtained by multiplying the obtained measurement result as a coefficient by the addition ratio in the coating liquid. The particle size distribution and distribution frequency of the coating liquid used in combination can be determined.

  As long as the inorganic fine particles contained in the hydrophilic layer are inorganic fine particles having the particle size distribution as described above, one kind of fine particles may be used. However, when two or more kinds are used in combination, the particle size distribution as described above can be obtained relatively easily. Therefore, it is preferable. Among them, it is preferable to use a combination of inorganic fine particles having an average primary particle size of 0.1 μm or more and less than 0.6 μm and inorganic fine particles having an average primary particle size of 0.6 μm or more and less than 2.0 μm. Inorganic fine particles may be further used in combination with three or four types. The amount of inorganic fine particles added is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total solid content of the hydrophilic layer. The upper limit is desirably 95% by mass.

  Regarding the dry solid content coating amount of the hydrophilic layer of the present invention, it is preferably formed in the range of 1 to 20 g per square meter in terms of dry mass. If it is less than this range, the printing durability is lowered, and if it is more, printing stains are likely to occur.

  Next, the photopolymerizable photosensitive layer which the photosensitive lithographic printing plate of the present invention has will be described. In the present invention, the photopolymerizable photosensitive layer preferably contains a compound having a polymerizable double bond group and a photopolymerization initiator. More preferably, the photopolymerizable photosensitive layer preferably has a layer formed by applying and drying an aqueous coating solution containing at least an emulsion of the above compound in water. Thereby, excellent development processing stability can be obtained.

  Examples of the compound having a polymerizable double bond group include a high molecular compound having a polymerizable double bond group or a low molecular compound having a polymerizable double bond group. The layer preferably contains a high molecular compound having a polymerizable double bond group and a low molecular compound having a polymerizable double bond group.

  The polymer compound having a polymerizable double bond group is a polymer compound formed by an arbitrary repeating unit, and is a polymer compound in which a polymerizable double bond group is bonded to a side chain through an arbitrary linking group. is there. Among them, a polymer compound having a vinyl group as a polymerizable double bond group is preferably used, and a polymer compound in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via an arbitrary linking group is particularly preferably used. It is done. In addition, it is preferable to introduce a carboxyl group, a sulfo group, a quaternary ammonium group, or the like linked to the main chain via an arbitrary linking group, but among them, a polymer compound having a sulfo group is preferably used because of its high developability. be able to. The sulfo group may form a salt (for example, sodium salt, potassium salt, lithium salt, ammonium salt, etc.). These linking groups are not particularly limited, and include any group, atom, or a combination thereof. The phenyl group and sulfo group substituted with a vinyl group may be independently bonded to the main chain, or the phenyl group substituted with a vinyl group and the sulfo group share part or all of the linking group. You may combine with.

  In the phenyl group substituted by the vinyl group, the phenyl group may be substituted, and the vinyl group is a halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. , An aryl group, an alkoxy group, an aryloxy group and the like may be substituted.

  With respect to the polymer compound having a polymerizable double bond group, for example, JP 2012-203131, JP 2012-208152, JP 2012-208331, JP 2012-208332, JP 2013. -20103 and the like, and can be used in the present invention. Although the specific example is shown below, it is not limited to these.

  The polymer compound having a polymerizable double bond group preferably has a weight average molecular weight in the range of 1,000 to 1,000,000, more preferably in the range of 50,000 to 600,000. In the present invention, the polymer compound having a polymerizable double bond group may be used alone or in combination of two or more kinds.

  Next, the low molecular weight compound having a polymerizable double bond group used in the present invention will be described. The low molecular compound having a polymerizable double bond group in this case can be preferably used as long as it is a compound that undergoes polymerization by radicals generated by photolysis of a photopolymerization initiator. Furthermore, when a low molecular weight compound having two or more polymerizable double bond groups in the molecule is used, a crosslinked product is formed as a result of polymerization by radicals, so that a photosensitive lithographic printing plate is formed. In this case, since a crosslinked hard image portion film is formed, a printing plate having excellent printing durability and ink carrying properties can be obtained, which can be used very preferably. Examples of low molecular weight compounds having a polymerizable double bond group that can be used for such purposes include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and tetraethylene glycol. Polyfunctional acrylic monomers such as diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and the like, or an acryloyl group, Polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. are similarly used as various oligomers having a methacryloyl group. It is use. The weight average molecular weight of the low molecular weight compound having a polymerizable double bond group is preferably less than 1000.

  As the photopolymerization initiator contained in the photopolymerizable photosensitive layer of the present invention, conventionally known compounds can be used. For example, trihaloalkyl-substituted compounds (for example, s-triazine compounds and oxadiazole derivatives as trihaloalkyl-substituted nitrogen-containing heterocyclic compounds, trihaloalkylsulfonyl compounds), organic boron salts, hexaarylbiimidazoles, titanocene compounds, thios Examples thereof include compounds and organic peroxides. Among these photopolymerization initiators, trihaloalkyl-substituted compounds and organic boron salts are particularly preferably used. More preferably, a combination of a trihaloalkyl-substituted compound and an organic boron salt is used. A combination of a trihaloalkyl-substituted compound and an organic boron salt is preferable because sensitivity can be further improved.

  The trihaloalkyl-substituted compound that is a photopolymerization initiator is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. Preferred examples include the trihaloalkyl group. S-triazine derivatives and oxadiazole derivatives may be mentioned as compounds in which is bonded to a nitrogen-containing heterocyclic group, or trihaloalkylsulfonyl in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group Compounds.

  Particularly preferred examples of compounds in which a trihaloalkyl group is bonded to a nitrogen-containing heterocyclic group and trihaloalkylsulfonyl compounds are shown below.

  Preferred specific examples of the organic boron salt that is a photopolymerization initiator are shown below.

  Further, the photosensitive layer of the present invention preferably contains a compound for sensitizing the above-mentioned photopolymerization initiator. As compounds that increase the sensitivity in the wavelength region of 400 to 430 nm, cyanine dyes, coumarin compounds described in JP-A-7-271284, JP-A-8-29973, etc., JP-A-9-230913, Carbazole compounds described in JP-A-2001-42524 and the like, carbomerocyanine dyes described in JP-A-8-262715, JP-A-8-272096, JP-A-9-328505, and the like. It is described in Kaihei 4-194857, JP-A-6-295061, JP-A-7-84863, JP-A-8-220755, JP-A-9-80750, JP-A-9-236913, etc. Aminobenzylidene ketone dyes, JP-A-4-184344, JP-A-6-301208, The pyromethine dyes described in Kaihei 7-225474, JP-A-7-5585, JP-A-7-281434, JP-A-8-6245, etc., and JP-A-9-80751 Styryl dyes or (thio) pyrylium compounds. Of these, cyanine dyes, coumarin compounds or (thio) pyrylium compounds are preferred.

  As described above, the photosensitive layer of the present invention is a layer formed by applying and drying an aqueous coating solution containing at least an emulsion in water of a compound having a photopolymerization initiator and a polymerizable double bond group. Is preferred. In preparing an emulsion in water containing the above-mentioned components, a photopolymerization initiator and a compound having a polymerizable double bond group are emulsified and dispersed in water in the presence of an anionic surfactant, so that they are exposed to a certain high temperature. However, it is preferable because an underwater emulsion capable of stably maintaining an emulsified dispersion state can be obtained. In addition, it is preferable from the viewpoint of storage stability of the coating liquid that a photopolymerization initiator, a compound having a polymerizable double bond group, and a sensitizing dye are emulsified and dispersed in water in the presence of an anionic surfactant.

  Examples of anionic surfactants used for emulsification and dispersion include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, alkyl sulfates such as sodium dialkylsulfosuccinate, sodium lauryl sulfate and sodium stearyl sulfate, and octyl. Sodium alcohol sulfate, sodium lauryl alcohol sulfate, higher alcohol sulfates such as ammonium lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, Alkyl naphthalene sulfones such as sodium butyl naphthalene sulfonate and sodium isopropyl naphthalene sulfonate Salts, alkyl diphenyl ether disulfonates such as sodium alkyl diphenyl ether disulfonate, alkyl phosphate esters such as sodium lauryl phosphate and sodium stearyl phosphate, polyethylene oxide adduct of sodium lauryl ether sulfate, polyethylene oxide adduct of ammonium lauryl ether sulfate, lauryl ether Polyethylene oxide adducts of alkyl ether sulfates such as polyethylene oxide adduct of triethanolamine sulfate, polyethylene oxide adducts of alkyl phenyl ether sulfates such as polyethylene oxide adduct of sodium nonylphenyl ether sulfate, sodium lauryl ether phosphate Polyether of alkyl ether phosphate such as polyethylene oxide adduct Alkylene oxide adducts, and polyethylene oxide adducts, and the like alkyl phenyl ether phosphate polyethylene oxide adduct of nonyl phenyl ether sodium phosphate. Of these, sodium dialkylsulfosuccinate, alkyl naphthalene sulfonates, and polyethylene oxide adducts of alkyl ether sulfates are particularly preferable because of the most improved dispersion stability.

  In addition, the dispersion stability of the emulsion in water is further improved by adding the above-described polymer compound having a polymerizable double bond group and a sulfo group that forms a salt to the system and emulsifying and dispersing. Since the polymer compound is water-soluble, it may be added at the time of emulsification dispersion for preparing an emulsion in water, or may be added after emulsification dispersion. Since the dispersed particle diameter is remarkably reduced and dispersed in the form of extremely fine droplets and fine particles, problems such as sedimentation or levitation over time are suppressed, which is more preferable. Furthermore, a part of the polymer compound may be used at the time of dispersion to prepare a dispersion, and after the stable dispersion is prepared, the polymer compound may be preferably added.

  The dispersion method for emulsifying and dispersing is not particularly limited, and any disperser such as a rotary disperser, a media mill such as a bead mill or a ball mill, an ultrasonic disperser, or a kneader can be used. A commercially available apparatus such as a homogenizer or a sand grinder can be preferably used.

  In preparing an emulsion in water, a compound having a photopolymerization initiator and a polymerizable double bond group is dissolved in advance in an organic solvent, or a photopolymerization initiator and a polymerizable double bond group are previously dissolved in an organic solvent. It is preferable to prepare an emulsion by the above-described dispersion method after dissolving the compound having a sensitizing dye and the sensitizing dye. The organic solvent that can be used may be any organic solvent that is liquid at room temperature and can dissolve or disperse a compound having a polymerizable double bond group, a photopolymerization initiator, or a sensitizing dye. Examples of organic solvents include volatile organic solvents and non-volatile organic solvents. When a volatile organic solvent is used, it is preferably removed from the system by heating or leaving the volatile organic solvent from the produced dispersion. In the case of using a non-volatile organic solvent, the non-volatile organic solvent exhibits a flash point higher than 50 ° C., which may reduce countermeasures as a dangerous substance in normal handling, which is preferable.

  Specific examples of the volatile organic solvent include, for example, acetates of lower alkanols such as ethyl acetate, propyl acetate and butyl acetate, ethylene glycol acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate. , Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, hydrocarbons such as hexane, cyclohexane and heptane, and aromatics such as benzene, toluene and xylene, etc., and ethyl acetate is most preferably used.

  Nonvolatile organic solvents include phosphoric acid esters, phthalic acid esters, acrylic acid esters, methacrylic acid esters and other carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, alkylated naphthalenes, diarylethanes, chlorinated paraffins, Examples include alcohol solvents, phenol solvents, ether solvents, monoolefin solvents, and epoxy solvents. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl olefinate, diethylene glycol benzoate, dioctyl sebacate, Dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isoamylbiphenyl, chlorinated paraffin, diisopropylnaphthalene, 1,1'-ditolylethane, monoisopropylbiphenyl, diisopropylbiphenyl, 2,4-ditertiaryamylphenol, N, N-dibutyl-2-butoxy-5-tertiaryoctylaniline, hydroxy Ikikosan ethylhexyl esters, high boiling point solvent such as polyethylene glycol.

  More preferably, the organic solvent used when preparing the emulsion in water is a volatile organic solvent. In this case, it is preferable because an underwater emulsion having the most stable dispersion state can be produced and the dispersion state can be kept stable even when exposed to a temperature higher than room temperature. As the volatile organic solvent, ethyl acetate is particularly preferable. Since ethyl acetate is highly volatile, it can be distilled off simply by placing it under heating or under reduced pressure. The emulsion in water after distillation of ethyl acetate is in a solid dispersion state and contains an organic solvent such as ethyl acetate. This is extremely preferable because it forms an aqueous coating solution that is more stable than the state. In the present invention, the aqueous coating solution means that water accounts for 50% by mass or more as a liquid medium component in the coating solution, and more preferably 80% by mass or more.

  As other elements constituting the photopolymerizable photosensitive layer of the photosensitive lithographic printing plate of the present invention, various colorants are preferably added for the purpose of improving visibility. As a colorant added for such purpose, an aqueous dispersion of a color pigment can be most preferably used. Examples of water-based dispersions of such pigments include various, black, blue, red, green, yellow, and other pigments that do not act as sensitizing dyes dispersed in water in the presence of various water-soluble dispersants. The material is usable. In particular, carbon black, phthalocyanine blue, phthalocyanine green, and the like as pigments are particularly preferred because they are readily available and relatively easy to disperse in water. Examples of dispersants that can be used to disperse these pigments in water include water-soluble nonionic surfactants having an oxyethylene group such as polyethylene glycol and polypropylene glycol, polyacrylic acid, and polyvinylpyrrolidone. , Polystyrene-maleic acid half ester copolymer, polystyrene-maleic acid copolymer, and other various water-soluble polymers. Such a dispersant is preferably contained in a range of 5 to 50 parts by mass with respect to 100 parts by mass of the color pigment. Furthermore, when using a color pigment, it is preferable that it is contained in 0.5-30 mass parts with respect to 100 mass parts of compounds which have a polymerizable double bond group.

  Regarding the dry solid content coating amount of the photopolymerizable photosensitive layer, it is preferably formed in the range of 0.3 to 10 g per square meter by dry mass, and further preferably in the range of 0.5 to 3 g. In addition, the printing durability of fine line images and fine dot images is ensured, and at the same time, the ink transportability is greatly improved. Arbitrary additives may be added to the aqueous coating solution used for coating the photopolymerizable photosensitive layer in order to improve coating properties and various properties as a lithographic printing plate.

  In the photosensitive lithographic printing plate of the present invention, it is also preferable to further provide a protective layer on the above-mentioned photopolymerizable photosensitive layer. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer to further improve exposure sensitivity in the atmosphere. It has a favorable effect of improving. Furthermore, an effect of preventing the photosensitive layer surface from scratches is also expected. Therefore, the properties desired for such a protective layer are low permeability of low molecular weight compounds such as oxygen and excellent mechanical strength, and further, light transmission used for exposure is not substantially inhibited, and a photopolymerizable photosensitive layer. It is desirable that it is excellent in adhesion to the surface and can be easily removed in the development step after exposure. In the photosensitive lithographic printing plate of the present invention, it is possible to simultaneously remove the unexposed portion of the protective layer and the photopolymerizable photosensitive layer in the process of chemicalless development. It is the feature that it is not necessary to provide. Furthermore, since the polymer contained in the photopolymerizable photosensitive layer as described above is water-soluble, it absorbs moisture in the atmosphere and causes blocking, and may cause problems such as sensitivity change during storage. However, such a problem of blocking or sensitivity change can be improved by providing a protective layer on the photosensitive layer. In addition, particularly when performing scanning exposure using a semiconductor laser or the like, the photosensitive layer is required to have particularly high sensitivity. In such a case, since the sensitivity is further increased by providing a protective layer, it can be particularly preferably applied.

  Such a device relating to the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic are used. Water-soluble polymers such as acids are known, and among these, using polyvinyl alcohol as a main component gives the best results for 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. There is a preferred range for the amount of dry solids applied when applying such a protective layer, and it is preferably formed on the photosensitive layer at a dry solids content in the range of 0.1 to 10 g per square meter. The range of 0.2-2g is preferable. The protective layer is coated and dried on the photopolymerizable photosensitive layer using various known coating methods.

  When applying the hydrophilic layer of the present invention, a photopolymerizable photosensitive layer provided on the upper layer, a protective layer, and the like, a coating liquid of a composition composed of the above-described elements is applied on a support. Made by drying. As the coating method, various known methods can be used, and examples thereof include bar coater coating, slide hopper coating coating, curtain coating, blade coating, air knife coating, roll coating, spin coating, and dip coating. it can.

  The light source used for exposure for forming an image pattern on the photosensitive lithographic printing plate of the present invention includes carbon arc, high pressure mercury lamp, ultra high pressure mercury lamp, low pressure mercury lamp, deep UV lamp, xenon lamp, metal halide lamp, tungsten lamp, halogen A lamp, an excimer UV lamp, an LED lamp, various fluorescent lamps (white fluorescent lamp, black light, chemical light, etc.) can be used, but scanning exposure with a laser is very preferable in terms of plate making efficiency. Examples of the laser light source include a blue-violet semiconductor laser (violet laser), an argon laser, a helium neon laser, a red LED, a near infrared laser, and an infrared laser. Among them, GaN having a wavelength region of 390 to 430 nm is preferably used from the viewpoint of productivity and image definition. The scanning method may be any of an internal drum system, an external drum system, a planar scanning system, etc., but an internal drum system is preferred.

  The developer in the development processing of the photosensitive lithographic printing plate of the present invention may contain an activator or an alkali agent as necessary for the purpose of improving the image quality and shortening the development time. In the case where the compound having a polymerizable double bond group has an acidic group such as a carboxyl group or a sulfo group, and the acidic group is in the form of a metal salt or an ammonium salt in the photosensitive layer, it will be described later. It is possible to develop with a developer that does not substantially contain the alkaline agent, that is, a neutral developer having a pH of less than 9. In particular, when the compound having a polymerizable double bond group has a neutralized salt of a sulfo group, good developability can be obtained, and elution with pure water is possible. In the case where sufficient solubility cannot be obtained even with a neutralized sulfo group salt, an activator can be added to the neutral developer for the purpose of improving developability. Nonionic properties such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, monoglyceride alkyl esters, alkylbenzene sulfonates, alkyl naphthalene sulfonic acids Anionic surfactants such as salts, alkyl sulfates, alkyl sulfonates, sulfosuccinate esters, amphoteric surfactants such as alkyl betaines, amino acids, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol And water-soluble organic solvents such as diacetone alcohol.

  The development is usually carried out by a known development method such as immersion development, spray development, brush development, ultrasonic development, etc., preferably at a temperature of about 10 to 60 ° C., more preferably about 15 to 45 ° C. for 5 seconds to It takes about 10 minutes. At that time, the protective layer provided as necessary on the photosensitive layer may be removed in advance with water or the like, or may be removed during development.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited by this description. In the following description, “%” and “part” are based on mass unless otherwise specified.

<Preparation of photosensitive lithographic printing plate 1>
A hydrophilic layer coating solution 1 having the following composition was applied on a polyethylene terephthalate film having a thickness of about 200 μm by a slide hopper coating method. At that time, the application was performed in advance such that the moisture application amount was 40 g / m ² . Immediately after coating, the coating film was gelled with cold air of 1 to 5 ° C., and then dried using a dry air set at 50 ° C. After drying, the hydrophilic layer was completed by putting it in a thermo-hygrostat adjusted to 40 ° C. and 40% RH and heating for 7 days.

<Hydrophilic layer coating solution 1>
10% alkali-treated gelatin aqueous solution 12.0 parts Inorganic fine particle slurry 1 (described below) 20.0 parts Surfactant: Polyoxyethylene lauryl ether sodium acetate 0.4 part (Daiichi Kogyo Seiyaku Co., Ltd. Neo Haitenol) ECL-45 10% solution)
Hardener (divinylsulfone, 5% solution) 4.0 parts The pH was adjusted to 7.0 with 1N sulfuric acid, and the total amount was adjusted to 40 parts by mass with water.

<Inorganic fine particle slurry 1>
An inorganic fine particle slurry was prepared with the following composition.
Water 13.0 parts Inorganic fine particles 1: Titanium dioxide 4.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle diameter≈0.3 μm,
Relative refractive index ≒ 2.04)
Inorganic fine particles 2: Barium sulfate (silica alumina surface treatment) 1.6 parts (B35, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle diameter ≈ 0.3 μm,
Relative refractive index ≒ 1.23)
Inorganic fine particles 3: Aluminum hydroxide 0.4 parts (H42, Showa Denko KK, average primary particle size ≈ 1.0 μm,
Relative refractive index ≒ 1.24)
Dispersant (acrylic acid copolymerized metal salt, 10% solution) 1.0 part

  Regarding the particle size distribution and distribution frequency of the inorganic fine particles contained in the inorganic fine particle slurry 1, the inorganic fine particles 2 and 3 contained in the inorganic fine particle slurry 1 are not added, and the inorganic fine particles 1 exist alone in the slurry. A liquid is prepared, and a slurry in which the inorganic fine particles 2 and 3 are present alone in the slurry is prepared in the same manner, and the particle size distribution and distribution frequency of each inorganic fine particle are measured by a laser diffraction / scattering type particle size distribution measuring apparatus. (LA920, manufactured by HORIBA, Ltd.), and the particle size distribution and distribution frequency of the hydrophilic layer coating solution 1 described above are calculated by multiplying the particle size distribution of each obtained single dispersion by the addition ratio as a coefficient. did. As a result, the distribution frequency fx of inorganic fine particles existing in the range of 0.2 μm or more and less than 0.6 μm is 64.8%, and the distribution frequency fy of inorganic fine particles existing in the range of 0.6 μm or more and less than 1.5 μm is It was 30.1% and fx / fy was 2.15.

<Photopolymerizable photosensitive layer>
On the hydrophilic layer obtained above, the following photosensitive layer coating solution was applied so that the solid content was 1.5 g / m ^2, and dried for 10 minutes in a drier at 75 ° C. after coating.

<Photosensitive layer coating solution>
Liquid compositions A and B having the following compositions were prepared.

<Liquid composition A>
300 parts of ion-exchanged water Polymer compound having a polymerizable double bond group (1-2 / weight average molecular weight 200,000)
20.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 5.0 parts (Perex OT-P: manufactured by Kao Corporation)
Colorant (Pigment Blue 15) 0.2 part

<Liquid composition B>
Trimethylolpropane triacrylate 6.0 parts Organic boron salt (3-2) 2.0 parts Trihaloalkyl-substituted compound (2-10) 1.5 parts 3-acryloxypropyltrimethoxysilane 0.5 parts Sensitizing dye ( Chemical Formula 4) 0.05 part 200 parts of ethyl acetate was added and dissolved.

  Liquid composition A was put into a vacuum emulsification apparatus PVQ-1D (manufactured by Mizuho Kogyo Co., Ltd.) and the rotation speed of the homomixer was set at 5000 rpm, and then liquid composition B was put into the vacuum emulsification apparatus at room temperature. Emulsification and dispersion were performed by high-speed stirring for 20 minutes using a homomixer. Thereafter, the inside of the vacuum emulsification apparatus was decompressed using an aspirator, the temperature was raised to 50 ° C. under a decompression condition of 20% of atmospheric pressure, and ethyl acetate was distilled off under reduced pressure to obtain a photosensitive layer coating solution. From the amount of ethyl acetate collected in the cooler, it was confirmed that all the ethyl acetate used was distilled off from the emulsion in water.

<Protective layer>
A coating solution is prepared according to the following protective layer formulation, coated on the photosensitive layer so that the solid content is 1.5 g / m ² , and then dried for 10 minutes in a 75 ° C. drier after coating. A sex lithographic printing plate 1 was obtained.

<Protective layer prescription>
Polyvinyl alcohol PVA-102 (manufactured by Kuraray Co., Ltd.) 1 part Surfactant (POE nonylphenyl ether sulfate, 10% solution) 0.4 part Ion-exchanged water 9 parts

<Preparation of photosensitive lithographic printing plate 2>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 2 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, photosensitive lithographic printing plate 2 was obtained.

<Inorganic fine particle slurry 2>
After adding 0.001 part of 3-aminopropyltriethoxysilane to the inorganic fine particle slurry 1, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 3>
In the preparation of the above-described photosensitive lithographic printing plate 1, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 3 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, photosensitive lithographic printing plate 3 was obtained.

<Inorganic fine particle slurry 3>
After 0.01 parts of 3-aminopropyltriethoxysilane was added to the inorganic fine particle slurry 1, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 4>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 4 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 4 was obtained.

<Inorganic fine particle slurry 4>
After adding 0.1 part of 3-aminopropyltriethoxysilane to the inorganic fine particle slurry 1, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 5>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 5 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 5 was obtained.

<Inorganic fine particle slurry 5>
After 0.01 parts of 3- (2-aminoethylamino) propyltrimethoxysilane is added to the inorganic fine particle slurry 1, the mixture is stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles are treated with a silane coupling agent. Went.

<Preparation of photosensitive lithographic printing plate 6>
In the production of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 6 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 6 was obtained.

<Inorganic fine particle slurry 6>
After 0.01 part of 3- (2-aminoethylamino) propyltriethoxysilane is added to the inorganic fine particle slurry 1, the mixture is stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles are treated with a silane coupling agent. Went.

<Preparation of photosensitive lithographic printing plate 7>
In the production of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 7 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 7 was obtained.

<Inorganic fine particle slurry 7>
After 0.01 parts of 3-aminopropyldiethoxymethylsilane was added to the inorganic fine particle slurry 1, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 8>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 8 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 8 was obtained.

<Inorganic fine particle slurry 8>
After 0.01 parts of N-methyl-3-aminopropyltriethoxysilane is added to the inorganic fine particle slurry 1, the mixture is stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles are treated with a silane coupling agent. It was.

<Preparation of photosensitive lithographic printing plate 9>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 9 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 9 was obtained.

<Inorganic fine particle slurry 9>
After 0.01 part of 3-acryloxypropyltriethoxysilane was added to the inorganic fine particle slurry 1, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 10>
In the preparation of the photosensitive lithographic printing plate 1 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 10 shown below was used instead of the inorganic fine particle slurry 1 contained in the hydrophilic layer coating liquid 1. Thus, a photosensitive lithographic printing plate 10 was obtained.

<Inorganic fine particle slurry 10>
An inorganic fine particle slurry was prepared with the following composition.
Water 13.0 parts Inorganic fine particles 1: Titanium dioxide 6.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd.)
Dispersant (acrylic acid copolymerized metal salt, 10% solution) 1.0 part

<Preparation of photosensitive lithographic printing plate 11>
In the production of the photosensitive lithographic printing plate 10 described above, the same procedure as in the photosensitive lithographic printing plate 1 was used except that the inorganic fine particle slurry 11 shown below was used instead of the inorganic fine particle slurry 10 contained in the hydrophilic layer coating liquid. A photosensitive lithographic printing plate 11 was obtained.

<Inorganic fine particle slurry 11>
After 0.01 parts of 3-aminopropyltriethoxysilane was added to the inorganic fine particle slurry 10, the mixture was stirred at 40 ° C. for 2 hours, and the dispersed inorganic fine particles were treated with a silane coupling agent.

<Preparation of photosensitive lithographic printing plate 12>
In preparing the photosensitive lithographic printing plate 1 described above, the photosensitive lithographic printing plate 1 was used in the same manner as the photosensitive lithographic printing plate 1 except that the hydrophilic layer coating solution 2 shown below was used instead of the hydrophilic layer coating solution 1. A lithographic printing plate 12 was obtained.

<Hydrophilic layer coating solution 2>
10% alkali-treated gelatin aqueous solution 12.0 parts 3-aminopropyltriethoxysilane 0.01 part After stirring at 40 ° C. for 2 hours, the following composition was added.
Inorganic fine particle slurry 1 20.0 parts Surfactant: Polyoxyethylene lauryl ether sodium acetate 0.4 part (Daiichi Kogyo Seiyaku Co., Ltd. Neo Haitenol ECL-45 10% solution)
Hardener (divinylsulfone, 5% solution) 4.0 parts The pH was adjusted to 7.0 with 1N sulfuric acid, and the total amount was adjusted to 40 parts by mass with water.

<Preparation of photosensitive lithographic printing plate 13>
In the preparation of the photosensitive lithographic printing plate 1 described above, the photosensitive lithographic printing plate 1 was used in the same manner as the photosensitive lithographic printing plate 1 except that the hydrophilic layer coating solution 3 shown below was used instead of the hydrophilic layer coating solution 1. A lithographic printing plate 13 was obtained.

<Hydrophilic layer coating solution 3>
Acrylamide / acrylic acid copolymer 10% solution 12.0 parts (molar ratio of acrylamide and acrylic acid 95: 5, average molecular weight 50,000)
Inorganic fine particle slurry 3 20.0 parts Surfactant: Polyoxyethylene lauryl ether sodium acetate 0.4 part (Daiichi Kogyo Seiyaku Co., Ltd. Neo Haitenol ECL-45 10% solution)
Hardener (ethylene glycol diglycidyl ether) 4.0 parts 1N sodium hydroxide was used to adjust the pH to 5.0, and the total amount was adjusted to 40 parts by mass with water.

<Preparation of photosensitive lithographic printing plate 14>
In the production of the photosensitive lithographic printing plate 1 described above, the photosensitive lithographic printing plate 1 was used in the same manner as the photosensitive lithographic printing plate 1 except that the hydrophilic layer coating solution 4 shown below was used instead of the hydrophilic layer coating solution 1. A lithographic printing plate 14 was obtained.

<Hydrophilic layer coating solution 4>
10% polyvinyl alcohol aqueous solution 12.0 parts (saponification degree 88%, average molecular weight 150,000)
Inorganic fine particle slurry 3 20.0 parts Surfactant: Polyoxyethylene lauryl ether sodium acetate 0.4 part (Daiichi Kogyo Seiyaku Co., Ltd. Neo Haitenol ECL-45 10% solution)
Hardener (Boric acid) 4.0 parts The total amount was 40 parts by mass with water.

  Each of the photosensitive lithographic printing plates 1 to 14 obtained above was subjected to the following evaluation.

<Exposure / Development>
For the photosensitive lithographic printing plates 1 to 14 obtained above, a test chart image was exposed using a blue-violet semiconductor laser emitting at 405 nm (output 60 mW) as an exposure light source and a plate surface exposure energy set to 200 μJ / cm ² . . Thereafter, water is poured into the developing tank 22 and the rinsing tank 23 of the photosensitive material processing apparatus 9 shown in FIG. 1, and the photosensitive lithographic printing plate M is inserted from the introduction guide 10 so that the photosensitive layer is on the upper side of the drawing. Processed. The developing tank 22 was provided with a scrub roller 33 having a diameter of 42 mm in the latter half of the processing step (position 4/5 from the entrance side with respect to the length in which the developer is immersed), and the water temperature was 30 ° C. In the rinsing tank 23, normal temperature water was washed by showering on the front and back of the photosensitive lithographic printing plate M, and then dried by blowing hot air of 40 ° C. The development processing conditions were set so that the rotation speed of the scrub roller 33 was 150 (rpm) and the conveyance speed of the photosensitive lithographic printing plate M was 11 (mm / second). The scrub roller 33 was rotated in the same direction as the conveying direction of the photosensitive lithographic printing plate M, and the contact pressure between the scrub roller 33 and the photosensitive lithographic printing plate M was set to 0.3 kg / 10 cm.

For each of the photosensitive lithographic printing plates 1 to 14, the photosensitive lithographic printing plate was processed in an amount of 20 m ² / L with respect to the volume of water charged into the developing layer 22, and the throughput was 0 m ² / L. Visual evaluation and printing evaluation of the following plate-making products were performed on the sample at the initial stage of the processing test and the sample at the end of the processing test when the processing amount was 20 m ² / L.

<Visual evaluation of platemaking>
For each of the photosensitive lithographic printing plates 1 to 14, as a result of visual evaluation of the plate-making product at the initial stage of the processing test and at the end of the processing test, sludge adheres to the non-image area in any printing plate at the initial stage of the processing test. There was no residue of the photosensitive layer. Table 1 shows the results of evaluation of the plate-making product at the end of the treatment test according to the following evaluation criteria.
○: Sludge is not seen in the plate-making product.
X: Sludge adheres to the plate-making product.

<Evaluation of printing durability>
With respect to each of the photosensitive lithographic printing plates 1 to 14, 30,000 sheets were printed on the plate at the initial stage of the processing test and at the end of the processing test under the following conditions. Table 1 shows the printing results.
Printing machine: RYOBI660H
Ink: T & K TOKA Corporation Super Tech GT Black SOYA (MZ)
Humidifier: Astro Mark III 2% by Nikken Chemical Research Co., Ltd.
Table 1 shows the results of evaluating the printed matter on which 30,000 sheets were printed according to the following evaluation criteria.
A: No change is seen in the printed image from the start of printing up to 30,000 sheets.
A: A change is observed at a halftone dot with an area ratio of less than 5%, but there is no omission at a halftone dot portion with an area ratio of 5% or more, and no decrease in ink density is observed.
(Triangle | delta): The missing | missing has generate | occur | produced in the halftone dot part whose area ratio is 5% or more, or the fall of the ink density of an image part is seen.
X: Missing occurs at a halftone dot portion having an area ratio of 5% or more, and a decrease in ink density in the image portion is observed.

  As can be seen from Table 1, according to the present invention, a photosensitive lithographic printing plate capable of forming an image portion capable of obtaining sufficient printing durability without deteriorating development processing stability can be obtained.

DESCRIPTION OF SYMBOLS 1 Developing part 2 Rinse part 3 Drying part 6 Drying mechanism 7 Exposure apparatus 9 Photosensitive material processing apparatus 10 Introduction guide 11 Introduction roller 22 Developing tank 23 Rinse tank 33 Scrub roller 35 Diaphragm roller 41 Pump 46 Waste liquid tank M Photosensitive lithographic printing plate

Claims (1)

  A photosensitive lithographic printing plate having at least a hydrophilic layer and a photopolymerizable photosensitive layer in this order on a support, wherein the hydrophilic layer is treated with a gelatin binder and a silane coupling agent having a primary amino group. A photosensitive lithographic printing plate comprising inorganic fine particles.