JP5255221B2 - Processless photosensitive lithographic printing plate - Google Patents

Description

  The present invention relates to a lithographic printing plate having a plastic film as a support, and having a hydrophilic layer and an image forming layer in this order on the support. In particular, a processless photosensitive printing plate that can be developed with water after forming an image on the image forming layer, or is mounted on a printing machine after image formation and removes non-image areas by supplying ink and dampening water to the plate surface. About.

  With the digitization of the plate making system, there is an increasing demand for a printing plate suitable for a computer-to-plate system (referred to as a CTP system) that directly outputs data formatted on a computer screen to a planographic printing plate. In particular, a processless photosensitive lithographic printing plate that can be developed with water or developed on a printing press from a development system that uses special chemicals normally used in conventional printing plates near a digital device, or a thermal phase. Non-photosensitive processless printing plates that have no development process using transfer or ink jet are drawing attention.

  The processless photosensitive printing plate and the CTP system using the processless printing plate do not use special developing chemicals, so there is no processing chemical cost or the waste liquid processing cost is reduced and the environmental load is reduced. With the advantages of Further, the film support printing system is advantageous in that it can be supplied in rolls and is lighter and easier to handle than a printing plate on an aluminum support.

  As these CTP systems, for example, a wax-coated printing plate having a melting point of 60 ° C. or higher is melted with a thermal head or a high-power near-infrared semiconductor laser, and the image forming layer is crosslinked by heat. A method of reacting and removing a non-crosslinked portion on water or a printing machine, or a method of printing an oleophilic substance in an image form on the surface of a printing plate with an ink jet head is known.

  Moreover, the non-image part (hydrophilic part) of the printing plate by these methods is, for example, a three-dimensional image having a porosity of 30 to 80% as disclosed in JP-A-9-99662 (Patent Document 1). A network structure, or a two-layer structure in which a chain colloidal silica is coated on a colloidal silica layer having an average particle diameter of 20 nm as disclosed in JP-A-2006-82321 (Patent Document 2) Alternatively, as disclosed in Japanese Patent Application Laid-Open No. 2000-158839 (Patent Document 3), a method of applying polyacrylic acid and colloidal silica on a support at a certain ratio is disclosed.

  However, the method using a thermal head and the method using an ink jet head do not require a development process, so there is no need to use a dedicated developing machine or developing chemicals, and the handling is simple and space-saving. Since a resolution image cannot be obtained, it cannot be used for a high-definition image.

  Furthermore, a hydrophilic layer, a photopolymerization layer, and a transparent cover film are formed on the metal support, and image exposure is performed on the cover film, and then the photopolymerization layer in the non-image area is peeled off together with the cover film. The method is shown. (Patent Document 4)

  According to this method, since the photocrosslinking reaction by the photopolymerization layer is used, an image with higher resolution can be obtained as compared with a method using a thermal head or an inkjet head. Moreover, since development is performed by peeling off the film, a developing machine or a processing agent is not used.

  However, the peeled film becomes a waste as it is, and further, if the film itself is damaged at the time of peeling, there is a problem that the peeling becomes incomplete. Furthermore, the method disclosed here has no problem in the adhesion between the metal support and the hydrophilic layer, but the plastic support has sufficient strength to withstand the printing of the hydrophilic polymer. It was difficult to bond with.

  In recent years, with the remarkable progress of semiconductor lasers, near-infrared laser light sources of 750 to 1100 nm can be easily used, and photosensitive materials and photosensitive lithographic printing plates corresponding to the laser beams have attracted attention. . When a photosensitive layer having light of this wavelength as a photosensitive region is used, a photosensitive layer having no sensitivity in the visible light region can be formed, and thus it can be handled under white light. However, in order to obtain a photosensitive layer that is sensitive to light in such a wavelength range, near infrared absorption that absorbs light of 750 to 1100 nm in order to increase the decomposition of the photopolymerization initiator or photoacid generator in the wavelength range. It is necessary to use a dye, and in such a system, it is particularly difficult to form an image and adhere the image to the hydrophilic layer.

  Examples of the photopolymerizable composition having photosensitivity to near-infrared light and capable of being developed with water or on-machine development include the method described in JP-A No. 2003-215801 (Patent Document 5). . According to this method, a photosensitive layer is applied to an aluminum support whose surface has been hydrophilized, or a hydrophilic layer is provided on a film support, and a phenyl group substituted with a vinyl group on the side chain is provided thereon. Cationic water-soluble polymer or water-soluble polymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonate group, a photopolymerization initiator or an acid generator, and a near red that sensitizes this to the wavelength range By applying a photosensitive layer characterized by containing an outer absorption dye, unexposed portions are removed by exposure with a near infrared laser of 750 to 1100 nm and subsequent water development, and an oleophilic image portion, and A non-image portion of the hydrophilic layer can be formed. As the hydrophilic layer provided on the film support, for example, a hydrophilic layer can be formed by using a (meth) acrylate polymer having a hydroxyalkyl group described in JP-B-49-2286. A composition containing a hydrophilic layer obtained by curing an acrylamide polymer described in Japanese Patent No. 83902 with aldehydes, a water-soluble melamine resin described in JP-A-62-280766, polyvinyl alcohol, and a water-insoluble inorganic powder. A hydrophilic layer obtained by curing, a hydrophilic layer having an onium group described in JP-A-10-296895, and a crosslinked hydrophilic polymer having a Lewis base moiety described in JP-A-11-311861 are polyvalent metal ions. Is obtained by three-dimensionally cross-linking a cross-linked hydrophilic polymer by interaction with polyvalent metal ions. The hydrophilic layer or the like containing a hydrophilic resin and a water dispersible filler are mentioned.

  According to the method of Patent Document 5, water development is possible, or development processing itself is unnecessary, and the optical system is contaminated by ablation residue, for example, as in the method of removing the image forming layer by ablation of a semiconductor laser. There is no problem that causes In addition, a high-definition image can be formed as compared with a method of dissolving wax or a printing plate using ink jet.

However, according to the method of Patent Document 5, when 10,000 or more sheets are printed, the ink gradually adheres to the hydrophilic portion of the non-image portion, and eventually causes printing stains. It was.
JP-A-9-99662 JP 2006-82321 A JP 2000-158839 A JP 7-325394 A JP 2003-215801 A

  The object of the present invention is to develop a processless photosensitive lithographic printing plate in which a hydrophilic layer is provided on a film support and a photosensitive layer on the film support. Without providing a processless photosensitive lithographic printing plate with good printing durability.

1) A water-soluble polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group and an acetoacetoxy group on a plastic film support, and an epoxy compound and an oxazoline as a crosslinking agent for crosslinking the water-soluble polymer A cationic water-soluble polymer having a hydrophilic layer containing a compound selected from a compound, an isocyanate compound, and a hydrazide compound, and further having a phenyl group substituted with a vinyl group on the side chain, or vinyl on the side chain A processless photosensitive lithographic printing plate comprising a water-soluble polymer having a phenyl group and a sulfonic acid group substituted with a group, and a photosensitive layer containing a photopolymerization initiator or a photoacid generator.
2) The water-soluble polymer having at least one functional group selected from the carboxyl group, amino group, hydroxyl group and acetoacetoxy group is a polymer represented by the following general formula (I): ) Processless photosensitive lithographic printing plate as described.

(In the 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 is a carboxyl group, amino group, hydroxyl group, acetoacetoxy as a reactive group. (Repeating unit having a group selected from the group is represented. Repeating unit B represents a repeating unit having a hydrophilic group necessary for making the copolymer water-soluble.)
3) The processless photosensitive lithographic printing plate as described in 1) or 2) above, wherein the photosensitive layer has a near infrared absorbing dye that absorbs light of 700 to 1100 nm.

  In the processless photosensitive lithographic printing plate provided with a hydrophilic layer on a film support and a photosensitive layer thereon according to the present invention, water development or development on a printing press is possible, and printing stains do not occur, It is possible to provide a processless photosensitive lithographic printing plate having good printing durability.

  The water-soluble polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group and an acetoacetoxy group used in the processless photosensitive lithographic printing plate of the present invention will be described. Specifically, the hydrophilic polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group, and an acetoacetoxy group is a water-soluble polymer represented by the following general formula (I). In the present invention, water-soluble means that 0.5 g or more is dissolved in 1 L of water.

  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 is a repeating unit having a group selected from a carboxyl group, an amino group, a hydroxyl group, and an acetoacetoxy group as a reactive group. The repeating unit B is a repeating unit having a hydrophilic group necessary for making the copolymer water-soluble.

The water-soluble polymer represented by the above general formula (I) needs to contain a reactive group in the molecule for allowing a crosslinking reaction to proceed efficiently with a crosslinking agent described later. Such reactive groups include carboxyl groups, hydroxyl groups, acetoacetoxy groups, amino groups or amino acid hydrochlorides, sulfates, phosphates, perchlorates, or organic acid salts such as acetates and citric acids. Can be mentioned. 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, Carboxyl group-containing monomers such as maleic acid monoalkyl ester, fumaric acid monoalkyl ester, 4-carboxystyrene, acrylamide-N-glycolic acid and their salts, allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl Methacrylate, 2-diethylaminoethyl acrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylamide, 4-aminostyrene, 4-aminomethylstyrene, N, N-dimethyl -N- (4-vinylbenzyl) amine, amino group-containing monomers such as N, N-diethyl-N- (4-vinylbenzyl) amine, 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, etc. Nitrogen heterocycle-containing monomer, (meth) acrylamides such as N-methylolacrylamide, 4-hydroxyphenylacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, glycerol mono Examples thereof include hydroxyalkyl (meth) acrylates such as methacrylate and acetoacetoxyethyl methacrylate, but are not limited to these examples.

  In the above general formula (I), X, which is the ratio of the repeating unit A in the copolymer, is preferably in the range of 1 to 40. Below this range, the water resistance is maintained even if the crosslinking reaction proceeds. If this range is not exceeded, the effect of introduction of the repeating unit B for imparting water solubility described below is reduced, and the affinity of the hydrophilic layer for water is reduced, which is not preferable.

  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-dimethylaminopro Methacrylamide, 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 preferred water-soluble polymers in the present invention are shown below.

  The average molecular weight of the water-soluble polymer is preferably 5,000 to 500,000, and more preferably 10,000 to 200,000. When the molecular weight is lower than this, the hydrophilic layer dissolves or peels off when it comes into contact with water. On the other hand, if it exceeds this range, the viscosity of the coating liquid becomes high and uniform coating becomes impossible.

The coating amount of these hydrophilic polymers is preferably 0.5 to 5 g / m ^2, more preferably 0.5 to 3 g / m ² .

  Examples of the crosslinking agent used in the hydrophilic layer of the processless photosensitive lithographic printing plate of the present invention include an epoxy compound, a compound having an oxazoline group, and a compound having an isocyanate group. The epoxy compound used in the present invention is preferably soluble in water, methanol or ethanol, and preferably has a hydrophilic group and two or more epoxy groups in the molecule. Preferred examples of the compound are given below.

  These compounds are sold by Nagase ChemteX Corporation under the trade name “Denacol” and can be easily obtained.

  In order for the crosslinking reaction to proceed efficiently between the epoxy compound as described above and the water-soluble polymer, a carboxyl group or an amino group is particularly preferable as the reactive group contained in the water-soluble polymer.

  As the oxazoline compound, a compound containing two or more of the following groups as substituents in the molecule is preferable. Examples of commercially available compounds include various grades provided by Nippon Shokubai Co., Ltd. under the trade name “Epocross”. These compounds are preferably used. In order for the crosslinking reaction to proceed efficiently between the oxazoline compound and the water-soluble polymer, a carboxyl group is particularly preferred as the reactive group contained in the water-soluble polymer.

  As the isocyanate compound, a compound that is stable in water is preferable, and a so-called self-emulsifiable isocyanate compound or a blocked isocyanate compound is preferably used. Examples of the self-emulsifiable isocyanate compound include Japanese Patent Publication No. 55-7472 (US Pat. No. 3,996,154), Japanese Patent Laid-Open No. 5-222150 (US Pat. No. 5,252,696), It refers to a self-emulsifiable isocyanate as described in the specifications of JP-A-9-71720, JP-A-9-328654, JP-A-10-60073, and the like. Specifically, for example, a polyisocyanate having an isocyanurate structure of a cyclic trimer skeleton formed from an aliphatic or alicyclic diisocyanate in the 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 specification. Specific examples of such isocyanate compounds are commercially available in which polyisocyanates by cyclic trimerization using hexamethylene diisocyanate or the like as a starting material are used as base polyisocyanates. For example, deyuranate WB40 or WX1741 is available from Asahi Kasei Corporation. Is available under the name Examples of the blocked isocyanate compound include bisulfite, alcohols, lactams, oximes, and active methylenes as shown in, for example, the specifications of JP-A-4-184335 and JP-A-6-175252. Blocked blocked isocyanates are preferably used. In order for the crosslinking reaction to proceed efficiently between the isocyanate compound and the water-soluble polymer, the reactive group contained in the water-soluble polymer is particularly preferably a hydroxyl group or an amino group.

  Examples of compounds that can be preferably used as hydrazide compounds are shown below. In order for the crosslinking reaction to proceed efficiently between the hydrazide compound and the water-soluble polymer, an active methylene group such as an acetoacetoxy group is particularly preferable as the reactive group contained in the water-soluble polymer. .

  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. Any of the various crosslinking agents described above is preferably used, but a particularly preferred crosslinking agent is an epoxy compound.

  The hydrophilic layer is produced by applying and drying a coating liquid of a composition composed of the above-described elements on a support. As the coating method, various known methods can be used, and examples thereof include bar coater coating, curtain coating, blade coating, air knife coating, roll coating, spin coating, and dip coating. Regarding the thickness of the photosensitive layer itself when used as a lithographic printing plate, it is preferably formed on the support with a dry thickness in the range of 0.3 μm to 10 μm, and more preferably in the range of 0.5 μm to 5 μm. This is preferable for improving the printability.

  The hydrophilic layer may contain a dye or a pigment in order to block light other than during exposure or prevent halation. Furthermore, by adding inorganic fine particles such as titanium oxide and silicon dioxide, irregularities can be made on the surface to improve the adhesion of the image area or improve the hydrophilicity of the non-image area.

  Furthermore, in order to sufficiently crosslink the cross-linking agent and the water-soluble polymer of the present invention, it is 12 hours to 1 at a temperature of 40 ° C. to 100 ° C., preferably 45 ° C. to 80 ° C., before applying the photosensitive layer. It is preferable to store for a week, preferably 1 day to 5 days.

  Next, the photosensitive layer used in the present invention will be described. The photosensitive layer of the processless photosensitive lithographic printing plate of the present invention has a cationic water-soluble polymer having a phenyl group substituted with a vinyl group on the side chain (hereinafter referred to as polymer A) or a vinyl group substituted on the side chain. A water-soluble polymer having a phenyl group and a sulfonic acid group (hereinafter referred to as polymer B). Hereinafter, the polymer A will be described in detail.

  The cationic group in the polymer A is a group selected from organic onium groups such as an ammonium group, a sulfonium group, a phosphonium group, an iodonium group, an oxonium group, and the like, and among these, a quaternary ammonium group is most preferable.

  The above-mentioned polymer having an organic onium group introduced therein is disclosed in JP-B-55-13020, JP-A-55-22766, JP-A-11-153589, JP-A-2000-103179, US Pat. No. 4,693,958, and JP-A-5. , 512, 418, can be synthesized using a conventionally known chemical reaction. That is, a monomer containing a desired organic onium group is subjected to a polymerization reaction, or a trivalent N atom, a divalent S atom or a trivalent P atom introduced into a polymer chain constituting the polymer is usually used. The method of introduce | transducing an organic onium group by alkylation reaction of these is mentioned. Furthermore, the nucleophilic substitution reaction between a nucleophilic reagent such as amines, sulfides, and phosphines and a polymer chain-like leaving group (for example, sulfonate esters or halides) results in the polymer main chain or side chain. A method of introducing an organic onium group is also mentioned.

  The phenyl group substituted with a vinyl group in the polymer A is a group that can contribute to a photopolymerization reaction or a photocrosslinking reaction by the action of a photopolymerization initiator or a photoacid generator. The phenyl group substituted with a vinyl group is preferably introduced into the polymer via an appropriate linking group. In this case, the linking group is not particularly limited, and includes any group, atom, or a combination thereof. Further, the vinyl group and the phenyl group may have a substituent. More specifically, the polymer into which a phenyl group substituted with a vinyl group is introduced has a group represented by the following general formula (II) in the side chain.

In the formula, R ₁ , R ₂ and R ₃ may be the same or different, and each is a hydrogen atom, a halogen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group. A group selected from a group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group The alkyl group and aryl group constituting these groups are a halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, hydroxy group, alkoxy group , Aryloxy group, alkylthio group, arylthio group, alkylamino Group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group and the like. Among these groups, those in which R ₁ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (for example, a methyl group, an ethyl group, etc.) and R ₂ and R ₃ are hydrogen atoms are particularly preferable.

In the formula, R ₄ is hydrogen atom, halogen atom, carboxyl group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkylamino group, A group selected from an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group. The alkyl group and aryl group constituting these groups are halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group. , An alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group and the like.

In the formula, m ₁ represents an integer of 0 to 4, p represents an integer of 0 or 1, and q ₁ represents an integer of ₁ to 4.

In the formula, L ₁ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, or a polyvalent linking group consisting of an atom group selected from a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom. Represent. Specific examples include groups composed of the structural units exemplified below and the heterocyclic groups shown below. These groups may be used alone or in any combination of two or more.

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

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

The case where an organic onium group such as a quaternary ammonium group forming a cationic group is contained in any atomic group constituting the linking group L ₁ is particularly preferably used. In the case where such an organic onium group is not contained in the linking group, it is necessary to separately include a repeating unit having an organic onium group in the repeating unit constituting the main chain.

  The method for introducing a phenyl group substituted with a vinyl group into the polymer is not particularly limited. For example, JP-B-49-34041, JP-A-6-105353, JP-A-2000-181062, and JP-A-2000-187322. Any method as shown in a publication or the like may be used. In these cases, when a polymer as a precursor is synthesized in advance, a repeating unit having an organic onium group is introduced in the form of a copolymer, or a polymerizable unsaturated bonding group is introduced into the precursor polymer. In form, it is necessary to form an organic onium group, such as by the method described above.

  Specific examples of monomers that can constitute the precursor of the polymer A include allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl methacrylate, 2-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylamide, 3-dimethylaminopropyl methacrylamide, 4-aminostyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-vinylbenzyl) ) Amino group-containing monomers such as amines 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 , ( -Vinylbenzyl) Quaternary phosphonium salt monomers such as trimethylphosphonium bromide, Tertiary sulfonium salt monomers such as dimethyl-2-methacryloyloxyethylsulfonium methosulfate, 2-chloromethylstyrene, 4-chloromethylstyrene, 4-bromomethyl Examples include, but are not limited to, halogenated alkyl group-containing monomers such as styrene, 2-chloroethyl acrylate, and 2-chloroethyl methacrylate.

  Further, the polymer A may constitute a copolymer with any other monomer, and the monomer constituting the copolymer may be water-soluble or water-insoluble. Specific examples of water-soluble monomers include 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 Carboxyl group-containing monomers such as monoalkyl esters, 4-carboxystyrene, acrylamide-N-glycolic acid and their salts, phosphoric acid group-containing monomers such as vinylphosphonic acid and their salts, allylamine, diallylamine, 2-dimethylaminoethyl Acrylate, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacryl Amino group-containing monomers such as amide, 4-aminostyrene, 4-aminomethylstyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-benzylbenzyl) amine, and the like; Nitrogen-containing heterocycle-containing monomers such as quaternary ammonium salts, 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, N-vinylcarbazole and the like, and quaternary ammonium salts thereof, acrylamide, methacrylamide, N, N -(Meth) acrylamides such as dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N-isopropylmethacrylamide, diacetoneacrylamide, N-methylolacrylamide, 2-hydroxyethyl methacrylate, 2-hydroxy Propyl Examples include hydroxyalkyl (meth) acrylates such as acrylate, 2-hydroxypropyl methacrylate, and glycerol monomethacrylate, alkyleneoxy group-containing (meth) acrylates of methacrylic acid, N-vinylpyrrolidone, and N-vinylcaprolactam. It is not limited. These water-soluble monomers may be used alone or in combination of any two or more.

  In order to optimize water developability and improve the strength of the image area, it is also preferable to form a copolymer with any water-insoluble monomer. Examples of these include styrene, 4- Styrene derivatives such as methylstyrene, 4-hydroxystyrene, 4-acetoxystyrene, 4-chloromethylstyrene, 4-methoxystyrene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl methacrylate, n-hexyl methacrylate Alkyl (meth) acrylates such as 2-ethylhexyl methacrylate, cyclohexyl acrylate, dodecyl methacrylate, aryl (meth) acrylates such as phenyl methacrylate, benzyl methacrylate, or arylalkyl (meth) acrylate , Acrylonitrile, methacrylonitrile, phenylmaleimide, vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate and other vinyl esters, methyl vinyl ether, vinyl ether such as butyl vinyl ether, and others, acryloyl Examples include various monomers such as morpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol, vinyltrimethoxysilane, and glycidyl methacrylate. A copolymer composed of any combination of these can be used as the polymer A.

  The polymer A of the present invention is particularly preferably a case where a phenyl group substituted with a vinyl group is bonded to the main chain via a cationic group. Arbitrary atomic groups constituting a linking group for bonding a phenyl group substituted with a vinyl group to the main chain include an organic onium group such as a quaternary ammonium group forming a cationic group. The case is most preferable. In this case, since the number of phenyl groups substituted with vinyl groups contained in the polymer is directly proportional to the number of organic onium groups, the vinyl groups contained in the polymer were substituted in order to improve sensitivity. Both phenyl groups can be satisfied simultaneously. The unit structure of the polymer in the case where the phenyl group substituted with the vinyl group as described above is bonded to the master through a cationic group can be specifically represented by the following general formula (III).

In the formula, A ₁ ⁺ represents an organic onium group selected from organic onium groups such as an ammonium group, a sulfonium group, a phosphonium group, an iodonium group, an oxonium group, and n ₁ and n ₂ each represents 0 or 1. When A ₁ ⁺ is an iodonium group, n ₁ = n ₂ = 0, when A ₁ ⁺ is a sulfonium group, n ₁ = 1 and n ₂ = 0, and when it is an ammonium group or a phosphonium group, n ₁ = N ₂ = 1.

In the formula, R ₅ and R ₆ may be the same or different, and are each an alkyl group (for example, a methyl group, an ethyl group, an isopropyl group, a cyclohexyl group, a benzyl group, etc.) or an aryl group (for example, These groups may be substituted, and examples of the substituent in this case include a halogen atom, a carboxyl group, a sulfo group, a nitro group, a cyano group, an amide group, Amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group , Alkylsulfonyl group, arylsulfonyl group and the like. Further, R ₅ and R ₆ may be a group containing a phenyl group substituted by a vinyl group represented by the general formula (III).

In the formula, R ₇ , R ₈ and R ₉ may be the same or different and have the same meanings as R ₁ , R ₂ and R ₃ in the general formula (II), respectively. Among these groups, those in which R ₇ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (for example, a methyl group, an ethyl group, etc.) and R ₈ and R ₉ are hydrogen atoms are particularly preferable. R ₁₀ has the same meaning as R ₄ in formula (II). L ₂ and L ₃ are each independently an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, or a polyvalent group consisting of an atom group selected from a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom. Specifically, it is synonymous with L < ₁ > in the said general formula (II). m ₂ represents an integer of 0 to 4, p ₂ represents an integer of 0 or 1, when p ₂ is 0 q ₂ represents 1, if p ₂ is 1 q ₂ is 1 to 4 Represents an integer.

A ring structure in which an N atom, an S atom, a P atom, or the like forming an organic onium group represented by A ₁ ⁺ is combined with a group arbitrarily selected from R ₅ , R _6, L ₂ , and L ₃ (For example, a pyridinium ring, 2-quinolium ring, morphonium ring, piperidinium ring, pyrrolidinium ring, tetrahydrothiophenium ring, etc.) may be formed. These ring structures are halogen atoms, carboxyl groups, sulfo groups, nitro groups, cyano groups, amide groups, amino groups, alkyl groups, aryl groups, alkenyl groups, alkynyl groups, hydroxy groups, alkoxy groups, aryloxy groups, alkylthio groups. , Arylthio group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group and the like.

  In the polymer A of the present invention, in addition to the polymer having a repeating unit in which a phenyl group substituted with a vinyl group as described above is bonded to the main chain through a cationic group, the vinyl group is substituted. A polymer having a repeating unit in which the phenyl group is bonded to the main chain directly or via a linking group containing no cationic group and a repeating unit having a cationic group can also be used.

  Examples of the polymer A in the present invention are shown below, but the present invention is not limited to these examples. The numbers in the exemplified structural formulas represent the mass% of each repeating unit in the copolymer total composition of 100 mass%.

  There exists a preferable range about the ratio for which each repeating unit which comprises the polymer A of this invention accounts in all the polymers. As described above, when the phenyl group substituted with the vinyl group is bonded to the main chain via a cationic group, the repeating unit may be in the range of 10% by mass to 80% by mass of the total polymer composition. Particularly preferred.

  In the case of a polymer comprising a repeating unit in which a phenyl group substituted by a vinyl group is bonded to the main chain directly or via a linking group not containing a cationic group and a repeating unit having a cationic group, a vinyl group In the case of a repeating unit having a substituted phenyl group, it is particularly preferably in the range of 5% by mass to 50% by mass. The proportion of the repeating unit having a cationic group is preferably in the range of 30% by mass to 95% by mass, and particularly preferably in the range of 50% by mass to 90% by mass. If the repeating unit having a cationic group is not 30% by mass or more, sufficient water solubility cannot be obtained, and if it is 90% by mass or less, sufficient image formation cannot be achieved.

  There is a preferred range for the molecular weight of the polymer A of the present invention, the weight average molecular weight is preferably in the range of 1,000 to 1,000,000, and more preferably in the range of 10,000 to 300,000. The polymer A in this invention may be used individually by 1 type, and may mix and use arbitrary 2 or more types.

  Next, the polymer (polymer B) having a phenyl group substituted with a vinyl group in the side chain and a sulfonic acid group will be described in detail.

  The polymer B of the present invention is a polymer in which a phenyl group substituted with a vinyl group and a sulfonic acid group are bonded to the main chain either directly or via an arbitrary linking group. These linking groups are not particularly limited, and include any group, atom, or a combination thereof. The phenyl group and the sulfonic acid group substituted with the vinyl group may be independently bonded to the main chain, or the phenyl group substituted with the vinyl group and the sulfonic acid group share part or all of the linking group. You may combine in the form to do.

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

  More specifically, the polymer B of the present invention has groups represented by the following general formulas (IV) and (V) in the side chain.

In the formula, R ₁₁ , R ₁₂ , and R ₁₃ may be the same or different, and are respectively synonymous with R ₁ , R ₂ , and R _{3 in the} general formula (II). ₁₄ has the same meaning as in the general formula (II). L ₄ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, or a polyvalent linking group consisting of a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom group; Is synonymous with L ₁ in formula (II). m ₁ represents an integer of 0 to 4, p ₃ represents an integer of 0 or 1, and q ₃ represents an integer of 1 to 4.

Among the groups represented by the above general formula, those in which R ₁₁ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (methyl group, ethyl group, etc.) and R ₁₂ and R ₁₃ are hydrogen atoms are preferred. . The linking group L ₄ preferably contains a heterocyclic ring, and q ₃ is preferably 1 or 2.

In the formula, L ₅ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom, or a polyvalent linking group consisting of a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom group, Specifically, it is synonymous with L ₁ in the general formula (II). Further, L ₅ may share part or all of L _{4 in} the general formula (IV).

In the formula, X ⁺ represents a cation having a charge necessary for neutralizing the sulfoanion. Specific examples of such cations include inorganic ions such as alkali metal ions, alkaline earth metal ions and transition metal ions (for example, sodium, potassium, calcium, magnesium, barium and zinc), organic ammonium ions (for example, ammonium, Triethylammonium, pyridinium, tetra-n-butylammonium, etc.), iodonium ions (eg, phenyliodonium, etc.), sulfonium ions (eg, triphenylsulfonium, etc.), diazonium ions, etc. Among these, alkali metal ions or organic ammonium ions are included. Particularly preferred.

  The method for introducing a phenyl group substituted with a vinyl group in the polymer is not particularly limited. However, when a monomer having a phenyl group substituted with a vinyl group is polymerized, the vinyl group also reacts to form a gel. It is anticipated that this will occur. Therefore, it is particularly preferable to synthesize a precursor polymer having no phenyl group substituted with a vinyl group, and then introduce a phenyl group substituted with the vinyl group by a conventionally known polymer reaction.

  The method for introducing a sulfonic acid group into the polymer is not particularly limited, and a monomer having the sulfonic acid group may be copolymerized, or a precursor polymer having no sulfonic acid group is synthesized, Thereafter, the sulfonic acid group may be introduced by a conventionally known polymer reaction.

  The polymer B of the present invention may be a polymer composed only of the above-described repeating unit having a phenyl group substituted with a vinyl group on the side chain and a repeating unit having a sulfonate group, or the effects of the present invention. As long as the above is not hindered, a polymer in which another repeating unit is further introduced may be used. Further, it may be a copolymer with another monomer, and specific examples of such a monomer include all the water-soluble monomers and water-insoluble monomers exemplified for the polymer A. One type may be used, or two or more types may be used.

  Examples of the polymer B of the present invention are shown below, but the present invention is not limited to these examples. The numbers in the exemplified structural formulas represent the mass% of each repeating unit in the copolymer total composition of 100 mass%.

  The mass average molecular weight of the polymer B of the present invention is preferably in the range of 1,000 to 1,000,000, and more preferably in the range of 10,000 to 300,000. The polymer B in this invention may be used individually by 1 type, and may mix and use arbitrary 2 or more types.

  There is a preferred range for the solubility of the aforementioned polymers A and B of the present invention in water. That is, 0.5 g or more of the polymer is preferably dissolved in 100 ml of ion-exchanged water at 25 ° C., more preferably 2.0 g or more.

  The photosensitive composition of the present invention can be used by mixing any known various binder resins in addition to the polymer A or B described above. The binder resin in this case is not particularly limited, and specifically, a polymer arbitrarily constituted from the monomers exemplified above, polyvinylphenol, phenol resin, polyhydroxybenzal, gelatin, polyvinyl alcohol, carboxymethylcellulose, etc. Cellulose resin, polyimide resin, and the like. These binder resins are preferably water-soluble, and are water-soluble binder resins using at least one or more water-soluble monomers as exemplified above, and water-soluble binder resins such as gelatin, polyvinyl alcohol, and carboxymethyl cellulose. Is preferred.

  In the photosensitive composition using the polymer A or B of the present invention, the phenyl group in which the vinyl group in the polymer is substituted in the exposed portion is crosslinked by the action of the photopolymerization initiator or photoacid generator. On the other hand, in the unexposed area, the water solubility becomes extremely high by introducing a cationic group or a sulfonate group. Accordingly, the unexposed area is removed by water development, while the exposed area is improved in image strength and hydrophobicity, so that it has stable water development suitability and high resolution can be obtained. The processless photosensitive lithographic printing plate of the present invention exhibits the effect that the ink acceptability to the image area, which has been difficult with the conventional water development type lithographic printing plate, is remarkably improved and the printing durability is excellent.

  Preferred between the ionicity of the polymer used in the hydrophilic layer of the processless photosensitive lithographic printing plate of the present invention and the polymer A (cationic) and polymer B (anionic) used in the photosensitive layer. There are combinations. That is, a photosensitive layer using an anionic polymer B for a hydrophilic layer using an anionic polymer, and a cationic polymer A for a photosensitive layer using a hydrophilic layer using a cationic polymer. And the elution property of a non-image part becomes favorable.

  In the prior art, it has been known that the similar polymerization activity of the styrene monomer is extremely low compared to the photopolymerization of the (meth) acrylate monomer by the radical generator. For example, reference is made to page 46 of Takahiro Tsunoda, “Photosensitive Resin”, published by the Printing Society Publishing Department, 1975. However, the present invention has found that a photosensitive composition capable of high-sensitivity and water-development can be obtained by using a polymer having a phenyl group substituted with a vinyl group which is a styrene type. It is. An important effect of the present invention is that crosslinking can be performed without being affected by oxygen in the air. Furthermore, it has been found that a photosensitive composition capable of high-sensitivity and water development can be obtained by using a photoacid generator.

  The photosensitive composition of the present invention contains a photopolymerization initiator or a photoacid generator in combination with the polymer A or B described above. 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 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 (j) organoboron compounds, and the like.

(A) Preferred examples of aromatic ketones include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” J.P.FOUASSIER, J.F.RABEK (1993), P.A. 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 organic peroxides include almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. For example, 3,3 ′, 4,4′-tetra (tert-butyl) Peroxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-hexylperoxycarbonyl) benzophenone, 3, 3 ', 4,4'-tetra (tert-octylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (cumylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra ( p-Isopropylcumylperoxycarbonyl) benzophenone, di-tert-butyldiperoxyisophthalate, etc. Tel systems are preferred.

(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'-teto Phenylbiimidazole, 2,2′-bis (o-methylphenyl) -4,4 ′, 5,5′-tetraphenylbiimidazole, 2,2′-bis (o-trifluoromethylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

(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-62-2623, 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.

(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.

  The organoboron anion constituting the organoboron salt is represented by the following general formula (VI).

In the formula, each of R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ may be the same or different, and represents an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group or heterocyclic group. Represent. Of these, it is particularly preferred that one of R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ is an alkyl group and the other substituent is an aryl group.

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

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

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

  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 achieve 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.

  The photopolymerization initiator and photoacid generator may be used alone or in any combination of two or more. Further, any photopolymerization initiator and any photoacid generator can be used in combination. The content of the photopolymerization initiator and the photoacid generator is preferably in the range of 1 to 100% by mass, more preferably in the range of 1 to 40% by mass, based on the amount of either the polymer A or B.

  As another preferable element constituting the photosensitive layer in the present invention, a polymerizable monomer having a polymerizable unsaturated bond group in the molecule can be exemplified. The polymerizable unsaturated bond group represents an ethylenically unsaturated double bond group that can contribute to a photopolymerization reaction or a photocrosslinking reaction by the action of a photopolymerization initiator or a photoacid generator. In particular, it is preferable to use a polyfunctional polymerizable monomer having two or more polymerizable unsaturated bond groups in the molecule. Examples of such polymerizable monomers include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trisacryloyloxyethyl isocyanurate, tripropylene. Polyfunctional acrylate monomers such as glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, etc., polyfunctional methacrylate monomers obtained by replacing acrylates of these exemplified compounds with methacrylates, and itaconic acid ester monomers , Crotonic acid ester monomers, maleic acid ester monomers, and the like.

  Examples of other polymerizable monomers include styrene derivatives. The styrene derivative is preferably a compound having two or more vinylphenyl groups in the molecule. For example, 1,4-divinylbenzene, 1,4-diisopropenylbenzene, 1,4-bis (4-vinylbenzyloxy) benzene, 1,2,3-tris (4-vinylbenzyloxy) benzene, 3,5-tris (4-vinylbenzyloxy) benzene, 2,2-bis [4- (4-vinylbenzyloxy) phenyl] propane, 1,1,2,2-tetrakis [4- (4-vinylbenzyl) Oxy) phenyl] ethane, α, α, α ′, α′-tetrakis [4- (4-vinylbenzyloxy)] p-xylene, 1,2-bis (4-vinylbenzylthio) ethane, 1,4- Bis (4-vinylbenzylthio) butane, bis [2- (4-vinylbenzylthio) ethyl] ether, 2,5-bis (4-vinylbenzylthio) -1,3,4-thiadiazole, 2 4,6-tris (4-vinylbenzylthio) -1,3,5-triazine, N, N-bis (4-vinylbenzyl) -N-methylamine, N, N, N ′, N′-tetrakis ( 4-vinylbenzyl) -1,2-diaminoethane, N, N, N ′, N′-tetrakis (4-vinylbenzyl) p-phenylenediamine, maleic acid bis (4-vinylbenzyl) ester, and the like.

  Alternatively, a polymerizable oligomer having radical polymerizability can be preferably used instead of the above polymerizable monomer. For example, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, and the like can be used in the same manner as the polymerizable monomer as various oligomers into which acryloyl group and methacryloyl group are introduced.

  Among the photosensitive layer compositions of the processless photosensitive printing plate of the present invention described above, a photosensitive composition using the polymer B is particularly preferable in that the strength of the image area is particularly excellent. When the photosensitive composition comprising the polymer B is used as a lithographic printing plate, the lithographic printing is particularly suitable for printing on a printing press without performing a development process and having excellent printing durability. You can get the original version.

  As sensitizing dyes at 700 to 900 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.

  Specific examples of sensitizing dyes that can be preferably used are shown below, but the present invention is not limited thereto. Sensitizing dyes corresponding to near-infrared light in the vicinity of 700 to 1100 nm are shown below.

  There is a preferable range for the content of the sensitizing dye as described above, and it is preferable to add in the range of 1 to 300 mg per square meter of the photosensitive layer of the processless photosensitive lithographic printing plate, and further, per square meter of the photosensitive layer. It is particularly preferable to add in the range of 5 to 200 mg.

  The photosensitive layer of the processless photosensitive lithographic printing plate of the present invention is preferably subjected to addition of other components for various purposes in addition to the components described above. In particular, it is preferable to add various polymerization inhibitors for the purpose of preventing thermal polymerization or thermal crosslinking of the polymerizable unsaturated bonding group and improving the long-term storage stability. As the polymerization inhibitor in this case, compounds having various phenolic hydroxyl groups such as hydroquinones, catechols, naphthols, and cresols, quinone compounds, and the like are preferably used, and hydroquinone is particularly preferably used. In this case, the addition amount of the polymerization inhibitor is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymer.

  As another element constituting the photosensitive layer of the processless photosensitive lithographic printing plate, a colorant can also be preferably added. As the colorant, it is used for the purpose of enhancing the visibility of the image area after exposure and development processing, such as carbon black, phthalocyanine dye, triarylmethane dye, anthraquinone dye, azo dye, etc. These dyes and pigments can be used, and it is preferably used in the range of 0.005 parts by mass to 0.5 parts by mass with respect to 1 part by mass of the polymer.

  About the element which comprises the photosensitive layer of a processless photosensitive lithographic printing plate, in addition to the above-mentioned element, other elements can be added and added for various purposes. For example, inorganic fine particles or organic fine particles are preferably added for the purpose of preventing blocking of the photosensitive composition or improving the sharpness of an image after development.

  The photosensitive layer of the processless photosensitive lithographic printing plate is prepared by applying and drying a coating liquid composed of the above-described elements on a support. As the coating method, various known methods can be used, and examples thereof include bar coater coating, curtain coating, blade coating, air knife coating, roll coating, spin coating, and dip coating. Regarding the thickness of the photosensitive layer itself when used as a lithographic printing plate, it is preferably formed on the support with a dry thickness in the range of 0.5 μm to 10 μm, and more preferably in the range of 1 μm to 5 μm. Is preferable in order to greatly improve.

  Suitable plastic film supports used as the support of the lithographic printing plate of the present invention include, for example, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, and propion. Examples include acid cellulose, cellulose butyrate, and cellulose nitrate. The surface of these plastic films is subjected to various hydrophilization treatments for the purpose of improving the adhesion with the photosensitive layer and imparting water retention to the non-image area. Such hydrophilic treatment includes chemical treatment, discharge treatment, glow discharge treatment, flame treatment, ultraviolet treatment, high-frequency treatment, active plasma treatment, laser treatment, and other surface treatments, and a hydrophilic layer is coated on the surface. The method etc. are mentioned, You may implement these processes in combination. When used as a lithographic printing application, printing durability is required, so the hydrophilic surface must be firmly bonded to the plastic film. For this reason, a method is particularly preferred in which after the chemical and physical surface treatment is applied to the plastic film, a hydrophilic layer that does not dissolve or swell in water is applied to increase the bonding force.

  The processless photosensitive lithographic printing plate material having the photosensitive layer formed on the support as described above is subjected to contact exposure or laser scanning exposure, and then a pattern is formed by removing an unexposed portion with a developer. Is done. The exposed portion is cross-linked, so that the solubility in a developing solution is lowered and an image portion is formed.

  The processless photosensitive lithographic printing plate material of the present invention is characterized in that it can be developed with water. The developer used for water development is substantially free of an alkali agent unlike a strong alkali developer (usually exceeding pH 10) which contains a large amount of an alkali agent generally used in the past. Therefore, the pH of the developer used in the water development of the present invention is 10 or less, preferably pH 9.5 or less, and more preferably pH 9 or less. The lower limit of pH is about 3. The developer used in the water development of the present invention is such that water accounts for 70% by mass or more, more preferably 80% by mass or more of the total developer, and other additives include ethanol, isopropanol, and n-butyl cellosolve. Further, various organic solvents such as ethylene glycol, diethylene glycol, triethylene glycol, glycerin and benzyl alcohol, or anionic, cationic and nonionic surfactants can be added. Furthermore, a commercially available printing plate surface protecting solution or a printing dampening solution can also be used.

  Next, typical synthesis examples of the water-soluble polymer used in the hydrophilic layer of the present invention will be given, but other exemplified compounds can be easily synthesized by referring to the same method or a conventionally known method as described above. I can do it. The method for synthesizing the polymer of the photosensitive layer can be synthesized according to the synthesis example described in JP-A-2003-215301.

Synthesis example 1
Example of synthesis of hydrophilic polymer (A-5) In a 1 L four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen introduction tube, 80 g of acrylamide and 20 g of acrylic acid were weighed, and 100 g of ethanol and 450 g of pure water were added. Added and dissolved. On a water bath adjusted to 60 ° C., 0.4 g of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as a polymerization initiator to initiate polymerization. Since the temperature of the system rose after the polymerization started, cold water was added to keep the internal temperature at 70 ° C., and stirring was continued at this temperature for 4 hours. The obtained copolymer solution was used for evaluation without purification. Other related water-soluble polymers were synthesized by the same synthesis method.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to these Examples as well as an effect.

  A coating solution for the hydrophilic layer having the following composition was prepared. Next, the coating solution was applied onto a polyethylene terephthalate film having a thickness of 0.10 mm and having a gelatin undercoat layer, and dried so as to have a dry thickness of 1.0 μm. This was put into a thermostat kept at 50 ° C. for 2 days to be crosslinked.

<Hydrophilic layer coating liquid 1>
Hydrophilic polymer (described in Table 1) 10.0 parts by mass (solid content)
Cross-linking agent (described in Table 1) 2.0 parts by mass (solid content)
Ethanol 10.0 mass parts It adjusted to 100g with water. The pH of the coating solution was adjusted to 4.0 using 1N sodium hydroxide and 1N sulfuric acid. The hydrophilic polymers and crosslinking agents used are listed in Table 1. In Table 1, Epocros WS-500 and Epocros WS-700 are oxazoline type crosslinking agents manufactured by Nippon Shokubai Co., Ltd., and Duranate WS40-100 is an isocyanate type crosslinking agent manufactured by Asahi Kasei Corporation.

A coating solution of a photosensitive composition having the following composition was prepared, and then the coating solution was applied on the hydrophilic layer in Table 1 so that the dry thickness was 1.0 μm, and dried at 70 ° C. for 2 minutes to obtain a sample. Was made.
<Coating liquid A>
Polymer A (CP-1) 3.0 parts by mass photopolymerization initiator (BC-6) 0.5 parts by mass photopolymerization initiator (T-4) 0.25 parts by mass sensitizing dye (S-4) 0 .1 part by weight Basic Blue 7 0.1 part by weight 1,3-dioxolane 25.0 parts by weight water 25.0 parts by weight

  A coating solution identical to the above coating solution was prepared except that the polymer used in the photosensitive layer was changed to polymer B (SP-1). This was applied and dried in the same manner as the coating liquid A. The produced comparative examples and samples of the present invention are shown in Table 1. Furthermore, the following composition was prepared as a coating liquid C, coated and dried under the same conditions as the coating liquid A and the coating liquid B, and samples were prepared as shown in Table 1.

<Coating liquid C>
Polymer (Polymer-1) 3.0 parts by mass Photopolymerization initiator (Polymerization initiator-1) 0.5 parts by mass Sensitizing dye (S-4) 0.1 parts by mass Basic blue 7 0.1 parts by mass Methyl ethyl ketone 25 0.0 parts by mass

The above sample is wound around a photosensitive drum, exposed to a test pattern of 2400 dpi and 175 lines with a laser beam having a wavelength of 830 nm and a spot diameter of 20 μm at an exposure energy of 120 mJ / cm ² , and then immersed in water at 25 ° C. for 15 seconds. The photosensitive layer was rubbed with a cellulose sponge, developed and dried. At this time, it was evaluated whether an image remained. The criteria for the remaining state of the image are as follows: ◯: the image portion remains clean Δ: a part of the image portion is missing ×: the entire image portion is removed. Further, the contact angle of the non-image area with water was measured. The lower the contact angle with water, the higher the wettability of the surface with water. As a result, the ink in the non-image area does not come close at the time of printing. The results are shown in Table 1.

  As can be seen from Table 1, in the sample of the comparative example, the image portion is removed or the contact angle with water is high. On the other hand, in the sample of the present invention, the image part remains intact and the contact angle of the non-image part is low. As a result, the lithographic printing plate of the present invention has good wettability of the non-image area with water while adhering the image area to the hydrophilic layer.

  The sample of Example 1 was subjected to a printing test using an H234C (Hamada Printing Machinery Co., Ltd.) offset printer. The dampening solution used was 1% of Toho Etch solution, and the ink used was New Champion Ink H (Dainippon Ink Chemical Co., Ltd.). Printing was carried out up to 20000 sheets, and printing durability was evaluated based on the following criteria for the number of printed sheets when the image was faint and for printing stains on the non-image area when printing 20000 sheets. ○: No printing stains occur. In addition, there is no dirt on the blanket. ◯: The printed material was not stained, but the blanket was stained. (Triangle | delta): Blanket stain | pollution | contamination generate | occur | produced at the time of printing 10000 sheets, and print stain | fouling generate | occur | produced slightly at the time of printing 20000 sheets. Δ ×: Print stain occurred when printing 10,000 sheets. X: Print stains occurred on the printed material when printing 1000 sheets. The results are shown in Table 2.

  As can be seen from Table 2, the non-image portion of the sample of the comparative example is stained or the image portion is blurred by about several thousand sheets, whereas the sample of the present invention has a blurred image portion even when printing 10,000 sheets or more. I didn't do it.

Claims (2)

  On a plastic film support, a water-soluble polymer having at least one functional group selected from a carboxyl group, an amino group, a hydroxyl group and an acetoacetoxy group, and an epoxy compound, an oxazoline compound as a crosslinking agent for crosslinking the water-soluble polymer, A cationic water-soluble polymer having a hydrophilic layer containing a compound selected from an isocyanate compound and a hydrazide compound, and further having a phenyl group substituted with a vinyl group on the side chain, or a vinyl group on the side chain A processless photosensitive lithographic printing plate comprising a water-soluble polymer having a substituted phenyl group and a sulfonic acid group, and a photosensitive layer containing a photopolymerization initiator or a photoacid generator. The water-soluble polymer having at least one functional group selected from the carboxyl group, amino group, hydroxyl group and acetoacetoxy group is a polymer represented by the following general formula (I): Processless photosensitive lithographic printing plate.

(In the 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 is a carboxyl group, amino group, hydroxyl group, acetoacetoxy as a reactive group. (Repeating unit having a group selected from the group is represented. Repeating unit B represents a repeating unit having a hydrophilic group necessary for making the copolymer water-soluble.)