JP2011209354A - Photosensitive composition, photosensitive lithographic printing plate material, and method of manufacturing the photosensitive lithographic printing plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-developable photosensitive composition having high sensitivity, excellent storage stability, high image quality, and excellent processability while being reduced in generation of sludge, which is derived from the photosensitive composition, in an exhausted developer even after continuous development; and a photosensitive lithographic printing plate material using the photosensitive composition and exhibiting excellent image quality and processing stability.SOLUTION: The photosensitive lithographic printing plate material uses the photosensitive composition, which is an emulsion in water prepared by emulsifying and dispersing a photopolymerization initiator (A) and a compound (B) having a polymerizable double bond group under the presence of a water-soluble polymer (C) having a sulfonate group and an anionic surfactant (D).

Description

  The present invention relates to a photosensitive composition developable with water, a photosensitive lithographic printing plate material using the same, and a method for producing a photosensitive lithographic printing plate material. In particular, high-sensitivity, excellent storage stability, high-quality, photosensitive composition with excellent processability due to reduced generation of sludge derived from the photosensitive composition in the development fatigue solution even if development processing continues. And a photosensitive lithographic printing plate material excellent in image quality and processing stability using the same and a method for producing the same.

  There are various fields of application as a photosensitive composition utilizing photopolymerization. For example, in applications such as photoresists and lithographic printing plates, development processing using an organic solvent or a strong alkaline reagent has recently been developed with water or the like. This is a very favorable trend from the viewpoint of environmental protection because the development of a possible system has been carried out, the handling of chemicals and equipment relating to development is easy. Especially in relation to lithographic printing plates, in recent years, computer-to-plate (CTP) technology has been developed to output directly on a printing plate without outputting it on film based on digital data produced on a computer. Various plate setters equipped with various lasers and photosensitive lithographic printing plate materials suitable for them have been actively developed. Important problems or requests that have been raised with the spread of the CTP method include various points related to development processing. In the normal CTP method, the photosensitive lithographic printing plate material is laser-exposed, the non-image area is eluted with an alkaline developer, and is subjected to water washing and gumming processes for printing. Alkaline developers are harmful to the human body, and their care and management are required for their handling and storage. Furthermore, the purchase cost and the cost associated with waste liquid treatment place a great burden on the user. In addition, the pH, temperature, etc. must be carefully managed as the liquidity of the alkaline developer. The handling is complicated and it has been difficult to always 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. For example, JP-A-5-27437 (Patent Document 1) discloses an aqueous photosensitive composition containing a carboxyl group-containing resin, an amine compound, a photocurable unsaturated compound, a photopolymerization initiator, and water. . However, in such a system, when an aqueous solution or an aqueous dispersion of the photosensitive composition is used as a coating liquid and a film is formed on a support and used in a dry film state, it is not suitable for storage over a long period of time. The developability deteriorated, or the film softened in a high humidity atmosphere, blocking occurred, or the photopolymerization initiator to be used decomposed over time, resulting in a decrease in sensitivity or loss of sensitivity.

  Alternatively, JP-A-2002-174898 (Patent Document 2) discloses a photosensitive composition dispersed in water using a urethane oligomer having a polyoxyalkylene structure. In this case, a photosensitive composition film excellent in flexibility can be obtained, but there is a problem that blocking tends to occur during storage in a high humidity atmosphere.

  Further, JP 2003-215801 A (Patent Document 3), JP 2008-265297 A (Patent Document 4) and the like disclose a cationic or anionic water-soluble polymer having a polymerizable double bond group in the side chain. A photosensitive composition that can be developed with water and a photosensitive lithographic printing plate material using the same are disclosed. In such a system, the storage stability problem as in the case of the above two examples does not occur, and a stable photosensitive composition that does not cause a change in sensitivity and does not easily cause blocking is provided. As a point, it had a problem of processing stability and a problem related to image quality. That is, regarding the processing stability, if the development processing with water is continued, the generation of sludge derived from the constituents of the photosensitive composition in the development fatigue liquid becomes remarkable. Filters installed in the circulatory system are clogged in a short period of time, the frequency of filter replacement increases, and various problems such as sludge sticking to the surface of the photosensitive composition film and causing image defects have occurred. It was. Furthermore, regarding the image quality, when the photosensitive composition is applied and dried, the compatibility between the water-soluble binder polymer and the hydrophobic photopolymerization initiator and other photosensitive components is poor, sometimes resulting in phase separation, Since a non-uniform film was formed, there was a problem that a uniform image quality was not given. In such a case, not only image quality but also high sensitivity has not been achieved, and improvement has been demanded.

JP-A-5-27437 JP 2002-174898 A JP 2003-215801 A JP 2008-265297 A

  Regarding the photosensitive composition that can be developed with water, the generation of sludge derived from the photosensitive composition in the development fatigue liquid was reduced even if the development process was continued with high sensitivity, excellent storage stability, and high image quality. To provide a photosensitive composition excellent in processability, a photosensitive lithographic printing plate material excellent in image quality and processing stability using the same, and a method for producing a photosensitive lithographic printing plate material.

  (A) Emulsification in water by emulsifying and dispersing a photopolymerization initiator and (B) a compound having a polymerizable double bond group in the presence of (C) a water-soluble polymer having a sulfonate group and (D) an anionic surfactant. An object of the present invention is a photosensitive lithographic printing plate material having a photosensitive composition and a photocurable photosensitive layer provided by applying and drying a coating liquid containing the photosensitive composition on a support. Is essentially resolved.

  It is a photosensitive composition that can be developed with water, and has high sensitivity, excellent storage stability, high image quality, and even if development processing is continued, generation of sludge derived from the photosensitive composition is reduced in the development fatigue solution. In addition, a photosensitive composition excellent in processability and a photosensitive lithographic printing plate material excellent in image quality and processing stability using the same are provided.

  First, an emulsion in water in which (A) a photopolymerization initiator and (B) a compound having a polymerizable double bond group are emulsified and dispersed in water will be described. It is known that a photopolymerization initiator and a compound having a polymerizable double bond group are generally water-insoluble compounds. In the present invention, any compound is basically used as long as it is insoluble in water. Can do. Specific examples of the compounds will be described in detail later. In the present invention, water-insoluble means that the solubility in water at 25 ° C. (the number of grams with respect to 100 g of water) is less than 0.1. In the present invention, it is important that these compounds are emulsified and dispersed in water. In order to stably and uniformly emulsify and disperse, (C) a water-soluble polymer having a sulfonate group and (D) an anionic interface The presence of an active agent is essential. In order to emulsify and disperse the photopolymerization initiator and the compound having a polymerizable double bond group in water, a solution is prepared using an organic solvent that can dissolve or disperse both, and a water-soluble polymer having a sulfonate group and A method of emulsifying and dispersing in the presence of an anionic surfactant is preferred. However, when the compound having a polymerizable double bond group is a liquid and the photopolymerization initiator is dissolved in this and the mixture of both is liquid, the mixture of both is emulsified without using an organic solvent. It is also possible to disperse. As a method for emulsifying and dispersing, a method in which an oily substance containing a photopolymerization initiator and a compound having a polymerizable double bond group is dispersed in water under high-speed stirring, shaking, or other high shear stress is preferable. Commercially available devices such as a homomixer and a homogenizer can be preferably used as the device used for the above.

  The organic solvent that can be used above means an organic solvent that is liquid at room temperature and can dissolve or disperse the photopolymerization initiator and the compound having a polymerizable double bond group. Examples of the organic solvent that can be used in the present invention include a volatile organic solvent and a nonvolatile organic solvent. 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 emulsion in water. In the case of using a non-volatile organic solvent, it is preferable that the non-volatile organic solvent exhibits a flash point higher than 50 ° C. and the countermeasures as a dangerous substance can be reduced in normal handling.

  Examples of the solvent that can be preferably used in the present invention as the above volatile organic solvent include lower alkanol acetates such as ethyl acetate, propyl acetate and butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl acetate. Ethylene glycol acetates such as ether, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, hydrocarbons such as hexane, cyclohexane, heptane, aromatics such as benzene, toluene, xylene, etc. Of these, ethyl acetate can be most preferably used for various reasons described later.

  Nonvolatile organic solvents that can be used in the present invention 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, Examples include diarylethane, chlorinated paraffin, alcohol solvent, phenol solvent, ether solvent, monoolefin solvent, epoxy solvent and the like. 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.

  Nonvolatile organic solvents such as the above exemplified compounds exhibit a flash point higher than 50 ° C., and the countermeasures as dangerous substances can be reduced in normal handling. Therefore, the photopolymerization initiator and polymerizable double bond group of the present invention can be reduced. It is not necessary to dare to remove from the emulsified and dispersed emulsion in water, and it is possible to prepare a photosensitive lithographic printing plate material to be described later using a coating solution containing these compounds.

  However, as the emulsion in water in which the photopolymerization initiator and the compound having a polymerizable double bond group that can be most preferably used in the present invention are emulsified and dispersed, the emulsion in water uses ethyl acetate. In the underwater emulsion, the underwater emulsion comprising both an anionic surfactant described later and a water-soluble polymer having a sulfonate group can be most stably produced, and is emulsified even when exposed to a temperature higher than room temperature. This is extremely preferable because the dispersion state is kept stable. In addition, since ethyl acetate has high volatility, it can be easily removed from the emulsion in water simply by placing it under heating or reduced pressure. The emulsion in water after distillation of the ethyl acetate is in a solid dispersion state. It is extremely preferable because it forms a photosensitive composition that is more stable than a state containing an organic solvent such as ethyl acetate.

  Examples of the anionic surfactant (D) that can be used in the present invention include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, alkyl such as sodium dioctylsulfosuccinate, sodium lauryl sulfate and sodium stearyl sulfate. Sulfates, higher alcohol sulfates such as sodium octyl alcohol sulfate, sodium lauryl alcohol sulfate, ammonium lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkyl benzenes such as sodium dodecylbenzene sulfonate Alkyl alcohols such as sulfonates, sodium butyl naphthalene sulfonate, sodium isopropyl naphthalene sulfonate Tarene sulfonates, 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 adducts of sodium lauryl ether sulfate, polyethylene oxide adducts of lauryl ether ammonium sulfate Polyethylene oxide adducts of alkyl ether sulfates such as polyethylene oxide adduct of lauryl ether sulfate triethanolamine, polyethylene oxide adducts of alkyl phenyl ether sulfates such as polyethylene oxide adduct of sodium nonylphenyl ether sulfate, lauryl Alkyl ethers such as polyethylene oxide adducts of sodium ether phosphate And polyethylene oxide adducts of phosphate, polyethylene oxide adducts of alkyl phenyl ether phosphate salts of polyethylene oxide adducts of nonyl phenyl ether sodium phosphate and the like. Of these, sodium dioctyl sulfosuccinate, alkyl naphthalene sulfonates and polyethylene oxide adducts of alkyl ether sulfates are particularly preferred because they form the most stable emulsions in water.

  There exists a preferable range about the quantity contained in the emulsion in water of the anionic surfactant used in this invention. The emulsion in water of the photosensitive composition of the present invention contains a photopolymerization initiator and a compound having a polymerizable double bond group emulsified and dispersed, but when an organic solvent such as ethyl acetate is used. It is preferable that the ratio of the optimal anionic surfactant with respect to 100 parts by mass of this emulsified dispersion is contained in the range of 0.5 to 50 parts by mass in the state of containing this and not being distilled off. When added at a ratio outside this range, the dispersion state of the emulsion may become unstable and cause aggregation and precipitation.

  Next, (C) a water-soluble polymer having a sulfonate group, which is another element contained in the emulsion in water of the photosensitive composition, will be described. As described above, an emulsion in water containing a photopolymerization initiator and a compound having a polymerizable double bond group is emulsified and dispersed using an anionic surfactant, so that the emulsion dispersion state is stable even when exposed to a certain high temperature. It was found that the emulsion dispersion stability was further improved by adding a water-soluble polymer having a sulfonate group to this system. In particular, the size of dispersed particles in water of an emulsion in water is significantly reduced by the addition of a water-soluble polymer having such a sulfonate group, and dispersed in the form of extremely fine droplets and fine particles. Alternatively, when a photosensitive lithographic printing plate material described later does not occur, the water-soluble polymer having the sulfonate group functions as a good binder polymer, and a photopolymerization initiator and a polymerizable Forms a homogeneous film containing a compound having a double bond group, so that developability with water is good, no sludge is generated even if development processing is continued, image quality is excellent, and sensitivity does not change over time. It has been found that a photosensitive lithographic printing plate material having high sensitivity can be obtained.

  The water-soluble polymer having a sulfonate group that can be used for such purposes is a water-soluble polymer having a substituent in which the sulfonic acid group is a salt neutralized with an arbitrary base, and can be preferably used in the present invention. Bases include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and amines such as ammonia, triethylamine, tributylamine, monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, diethylamino Ethanol, methylaminoethanol, ethylaminoethanol, n-butyldiethanolamine, t-butyldiethanolamine, or tetramethylammonium hydroxide, tetraethylammonium carbonate as a quaternary ammonium base Various bases such as doloxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, choline, phenyltrimethylammonium hydroxide, benzyltrimethylammonium hydroxide are preferably used for the purpose of neutralizing the sulfonic acid group. be able to.

  The water-soluble polymer having a sulfonate group that can be most preferably used in the present invention is a polymer obtained by polymerizing a monomer having a sulfonate group having a structure represented by the following chemical formula.

In the formula, L ₁ represents a linking group composed of any atom or group which may not be present, and represents an oxygen atom, a sulfur atom, an optionally substituted linear or branched alkylene group, an arylene group, —NH—, — The group which consists of COO-, -CONH-, -CO-, and these arbitrary combinations is represented. R ₁ represents a hydrogen atom or a methyl group. A ⁺ represents a cation.

  Examples of monomers having such a sulfonate group include alkali metal salts of vinyl sulfonic acid and amine salts thereof, quaternary ammonium salts, alkali metal salts of styrene sulfonic acid and amine salts thereof, quaternary ammonium salts, and acrylamide-2-methyl. Alkali metal salt of propane sulfonic acid and its amine salt, quaternary ammonium salt, Alkyl metal salt of allyl sulfonic acid and its amine salt, quaternary ammonium salt, Alkali metal salt of methallyl sulfonic acid and its amine salt, quaternary ammonium Preferred examples include salts, alkali metal salts of methacrylic acid 3-sulfopropyl ester, amine salts thereof, and quaternary ammonium salts. The alkali metal salt here is sodium salt, potassium salt and lithium salt, and the amine salt is amine, ammonia, triethylamine, tributylamine, monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, diethylaminoethanol, methyl Amines such as aminoethanol, ethylaminoethanol, n-butyldiethanolamine, t-butyldiethanolamine, or quaternary ammonium salts are tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetra Butylammonium hydroxide, choline, phenyltrimethylammonium hydroxide, benzyltrimethylammonium It means salts formed with arm hydro key side.

  As the water-soluble polymer having a sulfonate group that can be most preferably used in the present invention, a polymer obtained by polymerizing the above monomers having various sulfonate groups individually or in combination of several kinds may be used. As a more preferable example of the water-soluble polymer, a copolymer polymer obtained by combining the monomer having the sulfonate group with the following various copolymerization monomers is more preferable.

  Examples of the copolymerizable monomer that can be used for the above purpose include, for example, styrene derivatives such as styrene, 4-methylstyrene, 4-acetoxystyrene, 4-methoxystyrene, methyl (meth) acrylate, and ethyl (meth). Various alkyl (meth) acrylates such as acrylate and butyl (meth) acrylate, or monomers having a nitrogen-containing heterocycle such as 4-vinylpyridine, 2-vinylpyridine, N-vinylimidazole, N-vinylcarbazole, or 4 As monomers having a quaternary ammonium base, 4-vinylbenzyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, dimethylaminopropylacrylamido Quaternized product of methyl chloride, quaternized product of N-vinylimidazole with methyl chloride, 4-vinylbenzylpyridinium chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, dimethylacrylamide, diethylacrylamide, N-isopropyl Acrylamide, methacrylamide derivatives such as acrylamide, diacetone acrylamide, N-methylol acrylamide, N-methoxyethyl acrylamide, 4-hydroxyphenyl acrylamide, acrylonitrile, methacrylonitrile, phenylmaleimide, hydroxyphenylmaleimide, vinyl acetate, chloroacetic acid Vinyl, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate Vinyl esters such as methyl vinyl ether and butyl vinyl ether, and various other monomers such as N-vinyl pyrrolidone, acryloyl morpholine, tetrahydrofurfuryl methacrylate, vinyl chloride, vinylidene chloride, allyl alcohol and vinyl trimethoxysilane. It can be used as a polymerization monomer. The proportion of these copolymerization monomers in the copolymer polymer is less than 90% by mass at the maximum relative to the total, and in the copolymer polymer of the monomer having a sulfonate group contained in the copolymer The occupying ratio is preferably 10% by mass or more. More preferably, even when these copolymer monomers are included, the ratio to the whole is less than 70% by mass at the maximum, and the ratio of the monomer having a sulfonate group to the copolymer polymer is 30% by mass. When it is at least%, the solubility of the binder polymer in water is good, which is preferable.

  Among the above copolymer monomers, particularly preferred examples are mentioned. When the water-soluble polymer having a sulfonate group that can be used in the present invention has a structure that is hydrophobic to some extent, the ink transportability of the photosensitive lithographic printing plate material containing the water-soluble polymer is improved. It is mentioned as a preferable effect. That is, examples of copolymer monomers for imparting a hydrophobic structure to the water-soluble polymer having a sulfonate group include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl ( (Meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, c-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Various (meth) acrylic acid esters such as benzyl (meth) acrylate can be used very preferably.

  Examples of the water-soluble polymer having the sulfonate group that can be preferably used in the present invention are shown below. The numerical value in the figure represents the copolymer composition ratio (mass ratio).

  More preferable examples of the water-soluble polymer having a sulfonate group include a polymer having a polymerizable double bond group in the side chain. In this case, in the photosensitive lithographic printing plate material containing the binder polymer, a cross-linked structure is efficiently formed by photopolymerization in the image area (exposed area), so that a printing plate having extremely excellent printing durability is obtained. Therefore, it can be used very preferably. The proportion of the polymerizable double bond group introduced into these side chains in the copolymer polymer may be such that the proportion of the monomer having a sulfonate group in the copolymer polymer is 10% by mass or more. It can be introduced at any ratio. However, when the proportion of the monomer having a sulfonate group in the copolymer polymer is 30% by mass or more, the solubility of the binder polymer in water is preferable.

  Examples of the water-soluble polymer having the sulfonate group having a polymerizable double bond group in the side chain that can be preferably used in the present invention are shown below. The numerical value in the figure represents the copolymer composition ratio (mass ratio).

  As the most preferable example of the water-soluble polymer having a sulfonate group having a polymerizable double bond group in the side chain, for example, as described in JP-A-2008-265297, a sulfonate group and a heterocyclic ring are used. And polymers having both phenyl groups with vinyl groups attached to the side chains. Examples of such most preferred water-soluble polymers are shown below. The numerical value in the figure represents the copolymer composition ratio (mass ratio).

  There is a preferred range in the ratio of the water-soluble polymer as described above in the present invention to the emulsion in water containing the photopolymerization initiator and the compound having a polymerizable double bond group. When the water-soluble polymer is 100 parts by mass, a preferable range in which the photopolymerization initiator is included is 1 part by mass to 50 parts by mass, and a more preferable range is 3 parts by mass to 40 parts by mass. Furthermore, the preferable range in which the compound which has a polymerizable double bond group is contained is 10 mass parts-100 mass parts, More preferably, it is the range of 20 mass parts-60 mass parts. However, in the specific method for producing an underwater emulsion shown below, the water-soluble polymer is prepared by first preparing an underwater emulsion using a part of the water-soluble polymer. It is also preferable to add a functional polymer.

  A specific method for producing an emulsion in water in which a photopolymerization initiator of the present invention and a compound having a polymerizable double bond group are dispersed will be described. Using the organic solvent such as ethyl acetate described above, a solution in which a photopolymerization initiator and a compound having a polymerizable double bond group described later are dissolved or dispersed is prepared. When this is added to the water containing the anionic surfactant and the water-soluble polymer, the mixture is emulsified and dispersed using a known stirrer capable of high-speed shearing, such as a homomixer or a homogenizer. An emulsion in water in which a photopolymerization initiator and a compound having a polymerizable double bond group are dissolved can be prepared. Alternatively, regardless of the combination or the order of addition, the water-soluble polymer having a sulfonate group and the anionic surfactant were added regardless of the combination of the components in any order. If it is emulsified and dispersed in a state, the finally obtained emulsion in water finally shows similar characteristics. Furthermore, in any case, the emulsification dispersion method can be carried out by a batch method, or the emulsification dispersion can be continuously carried out in a state of flowing through the piping system by a continuous method. Moreover, regarding temperature, it is preferable to stir in the range of 0 degreeC to 70 degreeC.

  The emulsion of the compound having a photopolymerization initiator and a polymerizable double bond group dispersed as described above may be removed by removing the volatile organic solvent by further heating. Is possible. When the emulsified dispersion state is unstable, the dispersion may be agglomerated in such a heating distillation process. However, in the present invention, the emulsion in water may be placed in such a distillation process. It has been found that a stable emulsified dispersion state can be maintained.

  In the above distillation step, the volatile organic solvent may be distilled off by heating, but it is more preferable to distill off the organic solvent under reduced pressure. In general, the photopolymerization initiator that can be used in the present invention often decomposes when heated for a long time. When heating is performed, the temperature is preferably 70 ° C. or less and within a few hours within a short time. Heating is preferred. Therefore, when ethyl acetate is used as the volatile organic solvent, it can be distilled off at a temperature of 70 ° C. or lower, and it can be distilled off at a lower temperature by further reducing the pressure, which is extremely preferable. It is preferable to distill off the volatile organic solvent under the pressure of 70% to 5% of the atmospheric pressure as a standard as the above-mentioned decompression condition. The distilled organic solvent is preferably cooled and recovered in a separate container. By measuring the amount of the organic solvent recovered at this time, the amount of the volatile organic solvent in the underwater emulsion can be determined.

  Next, the photopolymerization initiator (A) used in the present invention will be described. Examples of photopolymerization initiators that can be used in the present invention include (a) aromatic ketones, (b) aromatic onium salt compounds, (c) organic peroxides, (d) hexaarylbiimidazole compounds, e) ketoxime ester compounds, (f) azinium compounds, (g) active ester compounds, (h) metallocene compounds, (i) trihaloalkyl-substituted compounds, and (j) organoboron compounds.

  (A) Preferred examples of aromatic ketones include compounds having a benzophenone skeleton or a thioxanthone skeleton described in “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” JPFOUASSIER, JFRABEK (1993), P. 77 to P. 177. Α-thiobenzophenone compounds described in JP-B-47-6416, benzoin ether compounds described in JP-B-47-3981, α-substituted benzoin compounds described in JP-B-47-22326, and JP-B-47. Benzoin derivatives described in JP-A-236364, aroylphosphonic acid esters described in JP-A-57-30704, dialkoxybenzophenones described in JP-B-60-26483, JP-B-60-26403, Benzoin ethers described in JP-A-62-181345 and JP-A-2-211452 P-di (dimethylaminobenzoyl) benzene, a thio-substituted aromatic ketone described in JP-A-61-194062, an acylphosphine sulfide described in JP-B-2-9597, and JP-B-2-9596 And the thioxanthones described in JP-B-63-61950 and the coumarins described in JP-B-59-42864.

  (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 Japanese Patent Publication No. 52-14277, Japanese Patent Publication No. 52-14278, Japanese Patent Publication No. 52-14279, and the like.

  (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 ' Tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethylphenyl) -4, Examples include 4 ', 5,5'-tetraphenylbiimidazole.

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

  Examples of (f) azinium salt compounds include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, JP-B-46. The compound group which has NO bond as described in -42363 gazette etc. can be mentioned.

  (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. be able to.

  (H) Examples of metallocene compounds include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. And titanocene compounds described in JP-A-1-304453 and iron-arene complexes described in JP-A-1-152109. Specific titanocene compounds include, for example, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3. , 4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti -Bis-2,4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4-difluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-T -Bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3- (pyr-1-yl) -phen-1-yl, etc. Can do.

  (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 Specification, U.S. Pat. No. 3,987,037, U.S. Pat. No. 4,189,323, JP-A-61-151644, JP-A-63-298339, JP-A-4-69661 And trihalomethyl-s-triazine compounds described in JP-A-11-153859, JP-A-54-74728, JP-A-55-77742, JP-A-60-138539, 2-Trihalomethyl-1,3 described in JP-A-61-143748, JP-A-4-362644, JP-A-11-84649, etc. 4- oxadiazole derivatives. 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 include JP-A-8-217813, JP-A-9-106242, JP-A-9-18885, JP-A-9-188686, JP-A-9-188710. Organoboron ammonium compounds described in JP-A-6-175561, JP-A-6-175564, JP-A-6-157623, and the like. Organoboron iodonium compounds described in JP-A-6-175553, JP-A-6-175554, etc., Organoboron phosphonium compounds described in JP-A-9-188710, JP-A-6-348011, JP-A-7- 128785, JP-A-7-140589, JP-A-7-292 14 JP, organic boron transition metal coordination complex compound described in JP-A-7-306527 Patent Publication, and the like. Examples of the counter anion described in JP-A-62-143044 and JP-A-5-194619 include cationic dyes containing an organic boron anion.

  The above photopolymerization initiators may be used alone or in any combination of two or more. As the photopolymerization initiator related to the present invention, an organic boron salt is particularly preferably used. More preferably, an organic boron salt and a trihaloalkyl-substituted compound (for example, an s-triazine compound, an oxadiazole derivative, or a trihaloalkylsulfonyl compound as a trihaloalkyl-substituted nitrogen-containing heterocyclic compound) are used in combination. One of the merits of using these is that the sensitivity as the resulting photosensitive composition is increased, and the sensitivity and printing durability as a photosensitive lithographic printing plate material using the same are improved. In addition, an important merit is that the emulsion in water of the photosensitive composition according to the present invention can be produced very stably. This is due to the fact that the organic boron salt and the trihaloalkyl-substituted compound are readily soluble in various organic solvents and can exist stably in an emulsified dispersion state and a solid dispersion state in the presence of the anionic surfactant.

  The organic boron anion constituting the organic boron salt is represented by the following general formula I.

In the formula, each of R ₂ , R ₃ , R ₄ and R ₅ may be the same or different, and represents an alkyl group, aryl group, aralkyl group, alkenyl group, alkynyl group, cycloalkyl group or heterocyclic group. To express. Of these, it is particularly preferred that one of R ₂ , R ₃ , R ₄ and R ₅ is an alkyl group and the other substituent is an aryl group.

  In the above-mentioned organoboron anion, a cation that forms a salt is simultaneously present. Examples of the cation in this case include alkali metal ions, onium ions, and cationic sensitizing dyes. Onium salts include ammonium, sulfonium, iodonium and phosphonium compounds.

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

  In the present invention, a trihaloalkyl-substituted compound can be used as a photopolymerization initiator that can achieve higher sensitivity when used with an organic boron salt. 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.

  Next, (B) the compound having a polymerizable double bond group contained in the emulsion in water of the photosensitive composition of the present invention will be described. The 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 the photodecomposition of the photopolymerizable initiator. Furthermore, when a compound having two or more polymerizable double bond groups in the molecule is used, a crosslinked product is generated as a result of polymerization by radicals. When constituted, it forms a cross-linked hard image part film, so that it can be used very preferably to give a printing plate excellent in printing durability and ink transferability. Examples of 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 diacrylate. Polyfunctional acrylic monomers such as trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, etc., or acryloyl group, methacryloyl Polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. are also used as various oligomers with introduced groups It is.

  In the photosensitive composition concerning this invention, it is preferable to contain the compound which sensitizes the above-mentioned photoinitiator together. 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 No. 2001-42524 and the like, carbomerocyanine dyes described in JP-A-8-262715, JP-A-8-272096, JP-A-9-328505, and the like, JP-A-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, 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. Examples of cyanine dyes that can be preferably used are shown below.

  Examples of preferred coumarin compounds are shown below.

  Examples of preferred (thio) pyrylium compounds are shown below.

  In particular, as sensitizing dyes in a long wavelength region such as near infrared light, cyanine dyes, porphyrins, spiro compounds, ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, phenothiazine, polyene, azo compounds, diphenylmethane, triphenyl Examples include methane, polymethine acridine, coumarin, ketocoumarin, quinacridone, indigo, styryl, squarylium compounds, (thio) pyrylium compounds, and further, European Patent No. 568,993 and US Patent No. 4,508,811. The compounds described in the specification and US Pat. No. 5,227,227 can also be used.

  Examples of preferable sensitizing dyes corresponding to near-infrared light in the long wavelength range are shown below.

  As other elements constituting the photosensitive composition of the present invention, various colorants are preferably added for the purpose of enhancing the visibility of the image. As a colorant added for such purposes, an aqueous dispersion of a color pigment can be most preferably used. As an example of an aqueous dispersion of such a pigment, any material in which various colored pigments such as black, blue, red, green and yellow are dispersed in water in the presence of various water-soluble dispersants can be used. . 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 for dispersing such 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 contained in the range of 1-30 mass parts with respect to 100 mass parts of water-soluble polymers which have the above-mentioned sulfonate group as a ratio contained in the photosensitive composition of this invention. It is preferable.

  As another element constituting the photosensitive composition of the present invention, a polymerization inhibitor is preferably added in order to prevent a curing reaction in the dark due to thermal polymerization, for long-term storage. Polymerization inhibitors preferably used for such purposes include hydroquinones, catechols, naphthols, cresols and other compounds having various phenolic hydroxyl groups, quinone compounds, 2,2,6,6-tetramethylpiperidine- N-oxyls, N-nitrosophenylhydroxylamine salts and the like are preferably used. In this case, the polymerization inhibitor is preferably used in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the photopolymerizable composition of the present invention.

  Examples of the support for forming the photosensitive lithographic printing plate material using the emulsion in water of the photosensitive composition of the present invention include various plastic films and aluminum plates. Typical examples of the plastic film support include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, and cellulose nitrate. In particular, polyethylene terephthalate and polyethylene naphthalate are preferably used. These films are preferably subjected to hydrophilic treatment on the surface of the film before providing a layer using the photosensitive composition according to the present invention on the surface.

  Examples of such hydrophilic treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. It is also preferable to provide a layer containing various water-soluble polymers on the film as a further hydrophilic treatment. For example, it is preferable to form a hydrophilic layer composed of a water-soluble polymer, colloidal silica and a crosslinking agent described in JP-A-2008-250195 on the film. Further, an undercoat layer may be provided in advance on the film in order to enhance the adhesiveness with the provided hydrophilic layer. As the undercoat layer, a layer containing a hydrophilic resin as a main component is effective. Examples of hydrophilic resins include gelatin, gelatin derivatives (for example, phthalated gelatin), hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, ethyl hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene oxide, xanthan, cationic hydroxyethyl cellulose, polyvinyl alcohol, A hydrophilic resin such as polyacrylamide is preferred. Particularly preferred are gelatin and polyvinyl alcohol. By forming the film support and the hydrophilic layer through such an undercoat layer, printing durability under long run printing conditions over a large number of copies is preferably used.

  When an aluminum plate is used as the support, an aluminum plate that is roughened and has an anodized film is preferably used. Furthermore, an aluminum plate whose surface is silicate-treated can also be preferably used. Alternatively, an aluminum plate having the above hydrophilic layer formed on the surface can also be used.

  In order to prepare a photosensitive lithographic printing plate material using the support as described above and the emulsion in water of the photosensitive composition of the present invention, the emulsion in water of the photosensitive composition of the present invention is used. It is necessary to provide a photocurable photosensitive layer by applying the coating solution contained on the support. The photocurable photosensitive layer is preferably formed on the support surface or the support surface via the hydrophilic layer. Regarding the dry solid content coating amount of the photocurable photosensitive layer itself in this case, it is preferably formed with a dry solid content coating amount in the range of 0.3 g to 10 g per square meter in dry mass, and further 0.5 g to 3 g. This range is extremely preferable in order to exhibit good resolution, ensure printing durability of fine line images and fine dot images, and at the same time greatly improve ink transportability.

  In the photosensitive lithographic printing plate material of the present invention, it is also preferable to further provide a protective layer on the photocurable photosensitive layer comprising the photosensitive composition of the present invention. The protective layer prevents the entry of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that inhibit the image formation reaction caused by exposure in the photocurable photosensitive layer into the photocurable photosensitive layer. It has a preferable effect of further improving the exposure sensitivity. 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, the transmission of light used for exposure is not substantially inhibited. It is desirable that it has excellent adhesiveness and can be easily removed in the development step after exposure. In the photosensitive lithographic printing plate material of the present invention, it is possible to simultaneously remove the unexposed portion of the protective layer and the photocurable photosensitive layer in the course of water development. The feature is that it is not necessary. Furthermore, when the polymer contained in the photo-curable photosensitive layer as described above is water-soluble, it absorbs moisture in the atmosphere and causes blocking, or causes a problem such as sensitivity change during storage. However, it is possible to solve such problems of blocking and sensitivity change by providing a protective layer on the photocurable photosensitive layer. In addition, in particular, when performing scanning exposure using a semiconductor laser or the like, a photocurable photosensitive layer having particularly high sensitivity is required. 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, but among these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. There is a preferred range for the coating amount of dry solids when applying such a protective layer, and it is preferable to form a dry solids coating amount on the photosensitive layer in the range of 0.1 g to 10 g per square meter in dry mass. Furthermore, the range of 0.2 g to 2 g is preferable. The protective layer is coated and dried on the photocurable photosensitive layer using various known coating methods.

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

  In the present invention, water used for water development has a pH in the range of 7 ± 2, and may contain pure water or various inorganic and organic ionic compounds. Sodium, potassium, calcium, magnesium Water containing ions and the like may be used. Alternatively, various surfactants known in water may be contained. Further, water may contain solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, propylene glycol, methoxyethanol, and polyethylene glycol as various alcohols. Alternatively, development by adding various commercially available gum solutions during water development can also be preferably used for the purpose of protecting the plate surface from fingerprint stains and the like.

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

(Examples 1-3 and Comparative Examples 1-4 of the photosensitive composition)
As a photopolymerization initiator, 2 parts of an organoboron salt represented by BC-6 and 1.5 parts of a trihaloalkyl-substituted compound represented by T-4 were weighed, and trimethylolpropane trimethyl compound was further prepared as a compound having a polymerizable double bond group. 6 parts of acrylate was added, and 200 parts of ethyl acetate was added and dissolved. To this solution, 0.6 part of a cyanine dye represented by S-38 as a sensitizer was further added and dissolved.

  On the other hand, 300 parts of ion-exchanged water was taken, and as shown in Table 1, in Examples 1 to 3, SP-2, SP-6 and SP-13 were respectively used as water-soluble polymers having a sulfonate group according to the present invention. 20 parts of each were added, and further 3 parts of OTP (sodium dialkylsulfosuccinate) as an anionic surfactant was added and dissolved. As Comparative Example 1, a system in which 3 parts of an anionic surfactant was added without adding the water-soluble polymer having a sulfonate group according to the present invention was prepared. In Comparative Example 2, 20 SP-2 was used as the water-soluble polymer. In addition, a system in which no anionic surfactant was added was prepared. Further, in Comparative Examples 3 and 4, a system using 20 parts of sodium polyacrylate was prepared instead of the water-soluble polymer having a sulfonate group according to the present invention, and in Comparative Example 3, an anionic surfactant was not added. A system was prepared, and in Comparative Example 4, a system to which 3 parts of an anionic surfactant was added was prepared.

  The underwater emulsion is prepared using a Mizuho Kogyo Co., Ltd. tabletop vacuum emulsifier PVQ-1D, which is equipped with a homomixer in an airtight container and capable of distilling the solvent while heating under reduced pressure. Went. The rotation speed of the homomixer was set to 5000 rpm. Introduce into the vacuum emulsifier the photopolymerization initiator prepared above, an ethyl acetate solution in which a compound having a polymerizable double bond group and a sensitizer are dissolved, and an aqueous solution in which a water-soluble polymer and an anionic surfactant are dissolved. The mixture was emulsified and dispersed by high-speed stirring with a homomixer at room temperature. A part of the sample was taken out from the emulsion in water obtained by stirring for 10 minutes, diluted with distilled water, and using a particle size distribution measuring device (Laser diffraction / scattering type particle size distribution measuring device LA-910 manufactured by Horiba, Ltd.). The particle size of the emulsion in water was measured immediately after dispersion. Furthermore, after stirring was continued for 10 minutes, the system was brought into a reduced pressure state using an aspirator, the temperature was raised to 50 ° C. under a reduced pressure condition of 20% of atmospheric pressure, and ethyl acetate was distilled off under reduced pressure. From the amount of ethyl acetate recovered by the cooler, it was confirmed that all the ethyl acetate used was distilled from the dispersion. The particle diameters after distilling off ethyl acetate are also summarized in Table 2.

  The emulsions in water obtained in Examples 1 to 3 were in a state in which fine particles comprising a photopolymerization initiator, a compound having a polymerizable double bond group and a sensitizer were stably emulsified even after distillation of ethyl acetate. However, in Comparative Example 1, the average particle size of the fine particles increased after the distillation of ethyl acetate, and some precipitates were observed at the bottom of the container. In Comparative Examples 2 to 4, the emulsion aggregated when the ethyl acetate was distilled off.

(Examples 4 to 6 and Comparative Example 5 of photosensitive lithographic printing plate material)
Using the emulsion in water obtained by distilling off ethyl acetate obtained in Examples 1 to 3, a coating liquid for producing a photosensitive lithographic printing plate material was prepared by further adding a colorant. As a colorant, a commercially available aqueous pigment dispersion (High Micron K Blue 7361 manufactured by Mikuni Color Co., Ltd.) in which a blue pigment is dispersed in water was used. The aqueous pigment dispersion used was obtained by dispersing a phthalocyanine pigment using a dispersant that is a water-soluble polymer. The dispersant was added to the phthalocyanine pigment in an amount of about 20%. The solid concentration was about 20%. A coating solution which is a blue photosensitive composition uniformly dispersed by adding 20 parts of the above-mentioned Hi-micron K blue to the total amount of the emulsion in water obtained in each of Examples 1 to 3. Was made.

  An anodized aluminum plate having a thickness of 0.3 mm and subjected to a silicate treatment using sodium silicate was used as a support. By applying and drying on the aluminum plate using the coating solution obtained above, a photocurable photosensitive layer was formed, and Examples 4 to 6 of photosensitive lithographic printing plate materials were prepared. The photocurable photosensitive layer was applied using a wire bar so that the dry weight was 1.6 g per square meter. Drying was performed by heating for 10 minutes in a dryer at 80 ° C.

  For comparison, a photosensitive composition solution was prepared using the following comparative photosensitive composition formulation 1. This solution is characterized in that it is a homogeneous solution in which an anionic surfactant and distilled water are not added to the emulsion in water of the photosensitive composition used in Example 3 above. When Himicron K Blue, which is an aqueous pigment dispersion used in Example 1 above, was added to this formulation, no coating solution was prepared because the pigment dispersion aggregated. For this reason, a commercially available solvent-based pigment dispersion prepared by adding about 20 parts of an organic solvent-soluble dispersant to the pigment using a phthalocyanine blue pigment as an organic solvent as a pigment dispersion and dispersing the pigment. 20 parts is added to the following comparative photosensitive composition formulation 1 using DHI Co., Ltd. MHI Blue # 454) and stirred to prepare a comparative coating solution that is a uniformly dispersed blue photosensitive composition. did. A photocurable photosensitive layer was formed by applying and drying on the above-mentioned aluminum plate using the obtained comparative coating solution, and Comparative Example 5 of a photosensitive lithographic printing plate material was produced. The photocurable photosensitive layer was applied using a wire bar so that the dry weight was 1.6 g per square meter. Drying was performed by heating for 10 minutes in a dryer at 80 ° C.

(Comparative photosensitive composition formulation 1)
Binder polymer (SP-13) 20 parts Trimethylolpropane triacrylate 6 parts Photopolymerization initiator (BC-6) 2 parts Photopolymerization initiator (T-4) 1.5 parts Sensitizing dye (S-38) 0. 6 parts ethyl acetate 300 parts

The photosensitive lithographic printing plate materials of Examples 4 to 6 and Comparative Example 5 thus obtained were used using an image setter PT-R4000 for thermal plate (drawing apparatus equipped with a 830 nm laser) manufactured by Dainippon Screen Mfg. Co., Ltd. The exposure was performed by adjusting the exposure amount irradiated to the plate surface to 160 mJ / cm ² . The exposed photosensitive lithographic printing plate material was developed under various conditions using ion-exchanged water and water containing no other additives.

(Developability test)
Using the sample exposed as described above, the developability test was performed as follows. The development was performed using an automatic developing device P-1310T manufactured by Mitsubishi Paper Industries. The development temperature is set to two conditions of 25 ° C. and 30 ° C., and the processing time is set to three conditions of 10 seconds, 15 seconds, and 20 seconds at each temperature, and the elution property of the non-image area (the remaining film is completely removed) The case where it disappeared was evaluated as ◯, the case where a slight residual film was observed was evaluated as Δ, and the case where a residual film was clearly generated and the dissolution was poor was evaluated as ×). The results are summarized in Table 3.

(Resolution evaluation)
As a resolution evaluation when processing using the developer described above, a case where a 10 μm fine line and a 1% halftone dot are clearly reproduced is indicated by ○, and these are partially missing, but 20 μm The case where the above fine line and the halftone dot of 2% or more were clearly reproduced was indicated by Δ, and the case where the reproducibility was less than this was indicated by ×. The results are summarized in Table 4. In Comparative Example 5, the coated surface of the photocurable photosensitive layer is not uniform, and there is an uneven skin-like unevenness at a pitch of about 20 μm, which adversely affects the image quality. Further, the sensitivity to the exposure amount is not sufficient, and the reproducibility of fine lines There was a bad result. In Examples 4 to 6, the coated surface of the photocurable photosensitive layer was uniform and the sensitivity was sufficient to give a high-resolution image.

(Printability test)
In order to perform normal offset printing using samples developed at 30 ° C. for 15 seconds, among the samples after the previous development processing, the printing press uses Ryobi 560, and the printing ink is black ink for offset printing. The hygroscopic liquid used was a 1% aqueous solution of the water absorbing liquid for offset printing Akwa Unity WKK manufactured by Toyo Ink Mfg. Co., Ltd. As printability evaluation, the printing durability was measured using a microscope (Omron Co., Ltd. CCD scope VC4500-PC) for every 10,000 sheets from the start of printing to 50,000 sheets. A case where a fine halftone dot portion having a 20 μm fine line and a halftone dot area ratio of 2% is reproduced on the printed material is indicated by ◯, a case where it is partially covered is indicated by Δ, and a case where it is almost completely omitted is indicated by ×. The ink transportability was measured using a reflection densitometer for each 10,000 printed matter. The results are summarized in Table 5. In addition, about the soiling at the time of printing, it did not recognize about all the tested samples. In Comparative Example 5, the image line was not uniform, and the sensitivity to the exposure amount was insufficient, which contributed to the printing durability.

(Water development processing running test)
Using each photosensitive lithographic printing plate on which drawing was performed as described above, an automatic developing device PD-912-M (manufactured by Dainippon Screen Mfg. Co., Ltd.) for an aluminum printing plate (PS plate) was used as an automatic development processing device. Development processing was performed. Ion exchange water adjusted to 30 ° C. was introduced into the developing tank, and the developing time was set to 15 seconds. The photosensitive lithographic printing plate material was adjusted so that the photocurable photosensitive layer in most non-image areas was removed by rubbing the surface of the photosensitive lithographic printing plate material weakly with a Molton roll in the developing tank. After rubbing development with a Molton roll, excess water on the surface of the photosensitive lithographic printing plate material was squeezed out by two squeezing rolls at the outlet of the developing tank. Subsequently, the surface was shower-washed in a water rinsing tank, and finally dried with warm air. In this development processing process, as water development property evaluation, (A) Presence / absence of sludge on the developing tank outlet squeeze roll, (B) Presence / absence of sludge sedimentation in the water development tank, (C) Treated photosensitive lithographic plate Four evaluation items were evaluated: presence or absence of sludge on the printing plate surface, and (D) presence or absence of a development residual film on the processed photosensitive lithographic printing plate. The evaluation was conducted by continuously passing the photosensitive lithographic printing plate materials of Examples 6 and Comparative Example 5 through an A3 size 100-plate automatic developing device. For the evaluation item (A), the case where sludge adheres to the developing tank outlet squeeze roll was evaluated as x, and the case where it did not occur was evaluated as ◯. As for the evaluation item (B), the case where the sedimentation of the sludge was remarkable was evaluated as x, and the state where the sludge was not generated and was uniformly dispersed was evaluated as ◯. For the evaluation item (C), the case where sludge adhesion was observed on the 100th plate was marked with x, and the case where adhesion was not recognized was marked with ○. For the evaluation item (D), the case where a developed residual film was observed on the 100th plate was rated as x, and the case where it was not recognized was marked as ◯. The results are summarized in Table 6.

  In Table 6, since the photosensitive lithographic printing plate of Example 6 had no sludge and no developed residual film in the running test, the previous printability test was conducted again on the 100th plate. Good printability was exhibited with no smudges. The photosensitive lithographic printing plate of Comparative Example 5 was not subjected to the printability test because a clear development residual film was generated in the running test.

(Storage stability test)
The photosensitive lithographic printing plate materials produced in Examples 4 to 6 were left in a humidifier adjusted to a relative humidity of 85% at 35 ° C. for 2 weeks. At that time, a polyester film having a thickness of 100 μm was placed on the surface of the photocurable photosensitive layer of each photosensitive lithographic printing plate material and allowed to stand to observe whether or not blocking occurred. In all of the photosensitive lithographic printing plate materials taken out in Examples 4 to 6, no blocking was observed. Furthermore, exposure was performed under the conditions described above, and a developability test was performed. The same results as the previous results were obtained, and the results of the resolution evaluation were the same, so changes were observed in the storage stability test. A good result was obtained.

  A photosensitive composition suitable for forming a photosensitive lithographic printing plate material that can be developed with water, a resist for preparing a printed wiring board, a color filter, a phosphor pattern, and the like is provided.

Claims (3)

  (A) Emulsification in water by emulsifying and dispersing a photopolymerization initiator and (B) a compound having a polymerizable double bond group in the presence of (C) a water-soluble polymer having a sulfonate group and (D) an anionic surfactant. A photosensitive composition.   A photosensitive lithographic printing plate material comprising a photocurable photosensitive layer provided by applying a coating liquid containing the photosensitive composition according to claim 1 on a support.   Use ethyl acetate to dissolve the photopolymerization initiator and the compound having a polymerizable double bond group, add an anionic surfactant and a water-soluble polymer having a sulfonate group, and add it to water under high shear. A method for producing a photosensitive lithographic printing plate material, comprising: dispersing an emulsion in water of a photosensitive composition; applying a coating solution containing the emulsion in water on a support; and drying.