JP2014186106A - Method of manufacturing photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a photosensitive lithographic printing plate having sufficient sensitivity and good printing durability even when exposed under low temperature environment, and good printing contamination resistance even after long-term storage.SOLUTION: There is provided a method of manufacturing a photosensitive lithographic printing plate containing (A) a (meth)acrylate compound having a molecular weight of less than 500 and equivalent of (meth)acrylate of less than 150, (B) a compound having two or more (meth)acryloyl groups in a molecule having the molecular weight of 500 to 5000, and (C) a photoinitiator, including coating a support having a hydrophilic surface with an aqueous photosensitive layer coating liquid obtained by emulsifying and dispersing the (A) to (C) in water.

Description

  The present invention relates to a method for producing a photosensitive lithographic printing plate in which a photosensitive layer coating solution is coated on a support having a hydrophilic surface.

  There are various fields of application as a photosensitive composition utilizing photopolymerization, but in particular in the field related to photosensitive lithographic printing plates, in recent years it has not been possible to output on a film based on digital data produced on a computer. Computer-to-plate (CTP) technology for direct output on a printing plate has been developed, and various plate setters equipped with various lasers as output machines and photosensitive lithographic printing plates suitable for these have been actively developed.

  Important issues or requests that have been raised with the spread of the CTP method include various points related to development processing. In a normal CTP method, a photosensitive lithographic printing plate is laser-exposed, and a non-image portion is eluted with an alkaline developer, and is subjected to printing through a water washing and gumming process. However, alkaline developers are harmful to the human body, and sufficient care and management are required for their handling and storage. In addition, purchase costs and costs associated with waste liquid treatment place a great burden on the user. In addition, alkaline developers must be carefully handled, with careful control of the pH and temperature of the developer. Was cumbersome.

  There has been proposed a photosensitive composition that avoids the use of such an alkaline developer and can be developed with water or the like. For example, 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. . JP-A 2003-215801 (Patent Document 2) uses a photosensitive composition using an anionic water-soluble polymer having a polymerizable double bond group in the side chain as a binder polymer for a photosensitive lithographic printing plate. Is disclosed. However, when the photosensitive layer obtained from the photosensitive composition described above is developed with water or the like using an automatic developing machine, the generation of sludge that accumulates in the aqueous developer becomes significant, and the sludge becomes a photosensitive composition coating. An image defect may occur on the surface, and improvement has been demanded.

  As a method for solving the above-mentioned problem, for example, JP 2011-209354 A (Patent Document 3) discloses a compound having a photopolymerization initiator and a polymerizable double bond group as a water-soluble polymer having a sulfonate group. A method of using an emulsion in water emulsified and dispersed in the presence of an anionic surfactant as a photosensitive layer coating solution is disclosed. In such a system, the above-mentioned problem of image defects due to sludge is solved, and a photosensitive lithographic printing plate having good storage stability can be obtained. However, a photosensitive lithographic printing plate produced using the emulsion in water as a photosensitive layer coating solution does not have sufficient sensitivity when exposed in a low temperature environment, specifically under a condition lower than 10 ° C., or When printing using a lithographic printing plate that has been stored for a long period of time, such as insufficient printing durability, printing stains may occur depending on the printing conditions. It was very difficult to obtain a photosensitive lithographic printing plate.

  On the other hand, Japanese Patent Application Laid-Open No. 9-95517 (Patent Document 4) describes a method for improving sensitivity and developability by combining an ethylenically unsaturated bond-containing compound and a compound having a urethane bond. JP-A-65210 (Patent Document 5) discloses a (meth) acrylate compound containing a urethane group having a molecular weight of 800 or less in the photosensitive layer, an alkylene oxide moiety in the linking group, and an ethylenically unsaturated double bond. The technology of a photosensitive lithographic printing plate is described that contains a (meth) acrylate compound having two of the above, and achieves both high printing durability and developability and does not cause printing stains.

JP-A-5-27437 JP 2003-215801 A JP 2011-209354 A JP-A-9-95517 JP 2006-65210 A

  The present invention is a photosensitive lithographic printing plate having sufficient sensitivity and good printing durability even when exposed in a low temperature environment, and having good printing stain resistance even after long-term storage. It is an object of the present invention to provide a method for producing a photosensitive lithographic printing plate from which can be obtained.

The above-described problems of the present application have been solved by the following invention.
(1) (A) a (meth) acrylate compound having a molecular weight of less than 500 and an equivalent weight of (meth) acrylate lower than 150, (B) a molecular weight of 500 to 5000, and two or more (meta) in one molecule The aqueous photosensitive layer coating solution obtained by emulsifying and dispersing (A) to (C) in water containing at least a compound having an acryloyl group, and (C) a photopolymerization initiator, has a hydrophilic surface. A method for producing a photosensitive lithographic printing plate to be coated on a support having the same.

  According to the present invention, a photosensitive lithographic printing plate having sufficient sensitivity and good printing durability even when exposed in a low-temperature environment, and having good printing stain resistance even after long-term storage. It is possible to provide a method for producing a photosensitive lithographic printing plate from which can be obtained.

  Hereinafter, the present invention will be described in detail.

  The aqueous photosensitive layer coating solution used in the method for producing a photosensitive lithographic printing plate of the present invention comprises (A) a (meth) acrylate compound having a molecular weight of less than 500 and an (meth) acrylate equivalent of less than 150, (B) A compound having a molecular weight of 500 to 5000 and having two or more (meth) acryloyl groups in one molecule and (C) a photopolymerization initiator, and emulsifying the (A) to (C) in water It can be obtained by dispersing. In addition, in (A), the equivalent of (meth) acrylate and the (meth) acrylate compound mean an equivalent of acrylate and / or methacrylate, and an acrylate compound or a methacrylate compound, respectively. The same applies to the (meth) acryloyl group of (B).

  About the (meth) acrylate compound (hereinafter referred to as compound A of the present invention) which (A) has a molecular weight of less than 500 and an equivalent weight of (meth) acrylate lower than 150, contained in the aqueous photosensitive layer coating solution of the present invention. explain. The equivalent of the (meth) acrylate of the compound A of the present invention is a value obtained by dividing the molecular weight of the compound A by the number of (meth) acryloyl groups contained in one molecule of the compound A. The compound A of the present invention is a compound having an equivalent weight lower than 150 and a molecular weight of less than 500, and the number of (meth) acryloyl groups that the compound A has in one molecule is preferably 2 to 6.

  The following are preferred examples of Compound A of the present invention, but are not limited thereto. In addition, together with the structural formula of the compound, the (meth) acrylate equivalent and the molecular weight of the compound are also described.

  The aqueous photosensitive layer coating solution used in the present invention comprises (B) a compound having a molecular weight of 500 to 5000 and having two or more (meth) acryloyl groups in one molecule in addition to the above-described compound A of the present invention. (Hereinafter referred to as Compound B of the present invention). Examples of the compound B of the present invention include epoxy (meth) acrylate compounds and urethane (meth) acrylate compounds.

  As an epoxy (meth) acrylate compound, a reaction product obtained by reacting an epoxy compound with an unsaturated monocarboxylic acid, or a reaction product obtained by reacting an epoxy oligomer with an unsaturated monocarboxylic acid and further adding a polybasic acid anhydride. Thing etc. are mentioned. Examples of the epoxy oligomer used here include bisphenol A type epoxy oligomer, bisphenol S type epoxy oligomer, novolak type epoxy oligomer, polyfunctional epoxy oligomer, etc., and unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, and cinnamic acid. And sorbic acid. Examples of the polybasic acid anhydride include maleic acid anhydride, and these epoxy (meth) acrylate compounds are preferably compounds having the following structural formula.

In the formula, A represents a phenylene group, and L represents a divalent linking group. Examples of L include —CH ₂ —, —S—, —SO ₂ —, —O—, —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, phenylene, and the like. A valent linking group may be combined. n represents an integer of 2 to 10. R represents a hydrogen atom or a methyl group. Examples of the compound B of the present invention having the above structural formula are shown below. The molecular weight of the compound is also shown.

  The compound B contained in the aqueous photosensitive layer coating solution of the present invention may be a urethane (meth) acrylate compound having a urethane bond. The urethane (meth) acrylate compound that can be used in the present invention has at least one urethane bond represented by the following structural formula in the molecule. Moreover, what has 2 or more of (meth) acryloyl groups in a molecule | numerator is preferable, Furthermore, the urethane (meth) acrylate compound which has 2-6 urethane bonds and 4-10 (meth) acryloyl groups is preferable.

  Specific examples of Compound B having a urethane bond that can be used in the present invention are shown below. The molecular weight of the compound is also shown.

  The content of Compound A and Compound B of the present invention contained in the aqueous photosensitive layer coating solution of the present invention is such that the total of Compound A and Compound B of the present invention is the total solid content contained in the aqueous photosensitive layer coating solution. It is preferable that it is 10-25 mass% with respect to 15-20 mass%. The ratio of the compound A to the compound B of the present invention is preferably such that the mass ratio of the compound A: the compound B is in the range of 10:90 to 90:10, more preferably 50:50 to 80:20. If the ratio of compound B is lower than this range, the printing durability may be slightly lowered. If the ratio of compound B is higher than this range, the printing stain resistance in long-term storage may be lowered.

  The aqueous photosensitive layer coating solution of the present invention contains (C) a photopolymerization initiator together with the above-described compounds A and B of the present invention.

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

  The photo-initiator trihaloalkyl-substituted compound is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or tribromomethyl group in the molecule. Examples of the compound in which a group is bonded to a nitrogen-containing heterocyclic group include s-triazine derivatives and oxadiazole derivatives, or a trihaloalkyl in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group Examples include sulfonyl compounds.

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

  The organoboron anion constituting the organoboron salt is represented by the following general formula 1.

In the formula, each of R ₁ , R ₂ , R ₃ and R ₄ 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 ₁ , R ₂ , R ₃ and R ₄ is an alkyl group and the other substituent is an aryl group.

  Examples of the cation constituting the organic boron salt include alkali metal ions and onium compounds, but onium salts are preferred, for example, ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and triarylalkyls. Examples thereof include phosphonium salts such as phosphonium salts. Examples of particularly preferred organic boron salts are shown below.

  The content of the photopolymerization initiator contained in the aqueous photosensitive layer coating solution is the polymerizable compound contained in the aqueous photosensitive layer coating solution of the present invention (herein, the polymerizable compound is the compound A or compound B of the present invention). And a polymer compound having a polymerizable unsaturated bond group and an acidic group (and its base) such as a carboxyl group and a sulfo group, which will be described later, contribute to the photopolymerization reaction or the photocrosslinking reaction by the action of the photopolymerization initiator. The range of 1 to 50% by mass is preferable, and the range of 5 to 30% by mass is more preferable, based on the sum of the compounds having a polymerizable unsaturated bond group.

  The aqueous photosensitive layer coating solution used in the method for producing a photosensitive lithographic printing plate of the present invention contains at least the above-described compounds A and B of the present invention and a photopolymerization initiator, and emulsifies and disperses them in water. Can be obtained at

  When compound A and compound B of the present invention and a photopolymerization initiator are contained and emulsified and dispersed in water, these compounds are emulsified and dispersed in water in the presence of an anionic surfactant. It is preferable because an emulsion in water that can stably maintain an emulsified and dispersed state even when exposed to a certain high temperature is obtained. Examples of such anionic surfactants include higher fatty acid salts such as sodium laurate, sodium stearate, and sodium oleate, alkyl sulfates such as sodium dialkylsulfosuccinate, sodium lauryl sulfate, and sodium stearyl sulfate, and octyl alcohol sulfate. Higher alcohol sulfates such as sodium, sodium lauryl alcohol sulfate, ammonium lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkyl benzene sulfonates such as sodium dodecylbenzene sulfonate, butyl naphthalene sulfone Alkyl naphthalene sulfonates such as sodium acid and sodium isopropyl naphthalene sulfonate Alkyl diphenyl ether disulfonates such as sodium didiphenyl 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 ammonium lauryl ether sulfate, trilauryl ether sulfate Polyethylene oxide adducts of alkyl ether sulfates such as polyethylene oxide adduct of ethanolamine, polyethylene oxide adducts of alkyl phenyl ether sulfates such as polyethylene oxide adduct of sodium nonylphenyl ether sulfate, polyethylene of sodium lauryl ether phosphate Polyethylene oxide of alkyl ether phosphates such as oxide adducts De adducts, and 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 dialkyl sulfosuccinate, alkyl naphthalene sulfonates and polyethylene oxide adducts of alkyl ether sulfates are particularly preferred because they form the most stable emulsions in water.

  Further, by adding a polymer compound having a polymerizable unsaturated bond group, which will be described later, and an acidic group (and its base) such as a carboxyl group or a sulfo group to this system, the emulsion dispersion stability is further improved, which is preferable. . The polymer compound may be added during the emulsification dispersion of the photopolymerization initiator or the compounds A and B of the present invention, or may be added after the emulsification dispersion. The dispersion particle diameter of the emulsion in water is remarkably reduced and is dispersed in the form of extremely fine droplets and fine particles, so that problems such as sedimentation or levitation over time are suppressed, which is more preferable. Furthermore, it is also possible to preferably perform a part of the polymer compound at the time of dispersion to prepare an underwater emulsion, and further add the polymer compound after a stable emulsion is prepared.

  In order to emulsify and disperse the photopolymerization initiator, the compound A of the present invention, and the compound B of the present invention in water, a solution is prepared using an organic solvent capable of dissolving or dispersing these compounds and mixed with water. In addition, it is possible to emulsify and disperse using the above-described anionic surfactant, a polymerizable unsaturated bond group, and a polymer compound having an acidic group (and its base) such as a carboxyl group or a sulfo group. From the viewpoint of the pot life of the photosensitive photosensitive layer coating solution. However, when the compound A of the present invention and the compound B of the present invention are liquid and the photopolymerization initiator is dissolved in this and the mixture of both is liquid, both of them can be used without using an organic solvent. It is also possible to emulsify and disperse the mixture in water. In preparing the aqueous photosensitive layer coating solution of the present invention, the photopolymerization initiator, the compound A of the present invention, and the compound B of the present invention are separately emulsified and dispersed, and the emulsified dispersion is mixed to prepare. Alternatively, they can be emulsified and dispersed after mixing them.

  As an organic solvent that can be used for emulsification and dispersion, an organic solvent that is liquid at room temperature and can dissolve or disperse the photopolymerization initiator, the compound A of the present invention, and the compound B of the present invention can be used. Examples of organic solvents that can be used in the present invention include volatile organic solvents and non-volatile organic solvents. When a volatile organic solvent is used, it is preferable to remove the volatile organic solvent from the produced emulsion in water by heating or leaving it. In the case of using a non-volatile organic solvent, the non-volatile organic solvent exhibits a flash point higher than 50 ° C., and the countermeasure as a dangerous substance may be reduced in normal handling, which is preferable.

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

  In the present invention, the organic solvent used for emulsifying and dispersing the photopolymerization initiator, the compound A of the present invention, and the compound B of the present invention is more preferably a volatile organic solvent. In this case, the emulsion in water can be most stably produced, and it is preferable because the emulsified dispersion state is kept stable even when exposed to a temperature higher than room temperature. As the volatile organic solvent, ethyl acetate is particularly preferable. Since ethyl acetate is highly volatile, it can be easily removed from the emulsion in water simply by placing it under heating or reduced pressure. The emulsion in water after the distillation of ethyl acetate is in a solid dispersion state, such as ethyl acetate. This is extremely preferable because it forms a coating solution that is more stable than a state containing a solvent.

  Next, the production method for emulsifying and dispersing the photopolymerization initiator of the present invention, the compound A of the present invention, and the compound B of the present invention in water will be described with specific examples.

  An organic solvent such as ethyl acetate as described above is used to prepare a solution in which the photopolymerization initiator, the compound A of the present invention, and the compound B of the present invention are dissolved or dispersed. When this is added to water containing an anionic surfactant or a polymer compound having a polymerizable unsaturated bond group and an acidic group (and its base) such as a carboxyl group or a sulfo group, a homomixer or homogenizer An aqueous photosensitive layer coating solution can be prepared by emulsifying and dispersing using a known stirring device capable of high-speed shearing. To the organic solvent, other water-insoluble compounds contained in the coating solution for coating the photosensitive layer of the present invention may be added, and the water used as the dispersion medium may contain other components contained in the coating solution. A water-soluble compound may be added. Moreover, the emulsification dispersion method can be carried out in a batch manner, or can be carried out continuously in a state of flowing through the piping system in a continuous manner, and in that case, the emulsification dispersion is carried out in a temperature range of 0 to 70 ° C. Is preferred.

  The polymer compound having a polymerizable unsaturated bond group and an acidic group (and its base) that can be used in the photosensitive layer of the invention will be described. This polymer compound is a polymer compound formed by an arbitrary repeating unit, and is a polymer compound in which a polymerizable unsaturated bond group is bonded to a side chain through an arbitrary linking group. Among them, a polymer compound having a vinyl group as a polymerizable unsaturated bond group is preferably used, and a polymer compound in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via an arbitrary linking group is particularly preferably used. It is done. In addition, in order to enable development with an alkaline developer or a neutral developer, an acidic group (and its base) such as a carboxyl group or a sulfo group linked to the main chain via an arbitrary linking group is introduced. However, a polymer compound having a sulfo group can be preferably used because of its high developability. The sulfo group may form a salt (for example, sodium salt, potassium salt, lithium salt, ammonium salt, etc.). These linking groups are not particularly limited, and include any group, atom, or a combination thereof. The phenyl group and the sulfo 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 sulfo group share part or all of the linking group. You may combine with.

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

  The polymer compound in which the phenyl group substituted with the vinyl group of the present invention is bonded to the main chain directly or through an arbitrary linking group has, in detail, one having a group represented by the following general formula 2 in the side chain. preferable.

In the formula, R ₅ , R ₆ and R ₇ may be the same or different and are each a hydrogen atom, halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. Group, aryl group, alkoxy group, aryloxy group, alkylsulfanyl group, arylsulfanyl group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group An alkyl group and an aryl group constituting these groups are 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, a hydroxy group, Alkoxy group, aryloxy group, alkylsulfanyl group, It may be substituted with a reelsulfanyl group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, or the like. Among these groups, those in which R ₅ and R ₆ are hydrogen atoms and 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.) are particularly preferable.

In the formula, R ₈ is hydrogen atom, halogen atom, carboxyl group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkoxy group, aryloxy group, alkylsulfanyl group, arylsulfanyl group, alkylamino. And a group selected from a 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 halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group. , Alkoxy groups, aryloxy groups, alkylsulfanyl groups, arylsulfanyl groups, alkylamino groups, arylamino groups, acyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups, arylsulfonyl groups, etc. good.

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.

The linking group L ₁ preferably includes a heterocyclic ring. 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 And a nitrogen-containing heterocycle such as a ring and a quinoxaline ring, a furan ring, a thiophene ring, and the like. 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, alkylsulfanyl group, arylsulfanyl group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, etc. It is done.

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

  The polymer compound having a polymerizable unsaturated bond group and an acidic group (and its base) is a polymer comprising only a repeating unit having a phenyl group having a vinyl group substituted on the side chain and a repeating unit having a sulfo group. Alternatively, a polymer into which another repeating unit is introduced may be used as long as the effects of the present invention are not hindered. Further, it may be a copolymer with another monomer, and such a monomer may be used alone or two or more of them may be used.

  Moreover, the high molecular compound which has a polymerizable unsaturated bond group and an acidic group (and its base) can introduce | transduce arbitrary substituents into the terminal of a polymer principal chain by using a chain transfer agent. Specifically, linear alkane thiols, particularly linear alkane thiols substituted with silicon atoms bonded to alkoxy groups or halogen atoms, are preferably used because they can be used at the time of polymerization as a chain transfer agent. Can do. Examples of such chain transfer agents include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrichlorosilane, 3-mercaptopropyldichloromethylsilane, 4 -Mercaptobutyltrimethoxysilane, 4-mercaptobutyldimethoxymethylsilane, 4-mercaptobutyltriethoxysilane, 4-mercaptobutyltrichlorosilane, 4-mercaptobutyldichloromethylsilane, and the like. May be bonded via an oxygen atom by hydrolytic condensation to form a siloxane bond.

  Although the preferable example of the high molecular compound which has a polymerizable unsaturated bond group and acidic group (and its base) of this invention is shown below, this 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 weight average molecular weight of the polymer compound having a polymerizable unsaturated bond group and an acidic group (and its base) that can be used in the present invention is preferably in the range of 1,000 to 1,000,000, more preferably 50,000 to 600,000. It is especially preferable that it is in the range. Further, the polymer compound in the present invention may be used alone or in a mixture of two or more kinds.

  In order to improve various properties as the photosensitive layer of the photosensitive lithographic printing plate, an arbitrary additive as described below may be added to the aqueous photosensitive layer coating solution of the present invention.

In recent years, an output machine equipped with a blue semiconductor laser having a transmission wavelength of 400 to 430 nm has been developed. This output machine has a maximum energy amount of about several hundred μJ / cm ² , and the photosensitive material used is required to have high sensitivity. In the present invention, a photosensitive lithographic printing plate corresponding to this output machine can be obtained by combining the following sensitizing dye with the aqueous photosensitive layer coating solution.

  The content of the sensitizing dye is preferably in the range of 0.01 to 3% by mass, more preferably in the range of 0.5 to 1.5% by mass with respect to the photopolymerization initiator.

  As other elements constituting the photosensitive layer of the photosensitive lithographic printing plate of the present invention, various colorants are preferably added for the purpose of enhancing the visibility of the image. For this purpose, an aqueous dispersion of a color pigment can be most preferably used as a colorant added to the aqueous photosensitive layer coating solution. 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 to disperse these pigments in water include water-soluble nonionic surfactants having an oxyethylene group such as polyethylene glycol and polypropylene glycol, polyacrylic acid, and polyvinylpyrrolidone. Styrene-maleic acid half ester copolymer, styrene-maleic acid copolymer, and other various water-soluble polymer compounds. Such a dispersant is preferably contained in a range of 5 to 50 parts by mass with respect to 100 parts by mass of the color pigment. Furthermore, when using a color pigment, it is preferable that it is contained in 0.5-30 mass parts with respect to 100 mass parts of compounds which have a polymerizable unsaturated bond group.

  The aqueous photosensitive layer coating solution of the present invention preferably contains a silane coupling agent. Excellent printing durability can be obtained when the photosensitive layer contains a silane coupling agent. The silane coupling agent is not particularly limited as long as the purpose is achieved, and any silane coupling agent can be used. For example, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxy Silane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, styryltrimethoxysilane, styryltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane , Vinyltris (3-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimeth Sisilane, 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyl Trimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -amino Propylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane 3-isocyanatopropyltriethoxysilane and the like. Among them, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltri Particularly preferred are trialkoxysilanes such as ethoxysilane. In addition, a silane coupling agent may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The amount of the silane coupling agent contained in the aqueous photosensitive layer coating solution is preferably in the range of 0.05 to 20% by mass with respect to the compound having a polymerizable unsaturated bond group contained in the coating solution. Preferably it is the range of 0.1-10 mass%.

  In the aqueous photosensitive layer coating solution used in the present invention, a polymerization inhibitor can be added in order to extend the sensitivity maintaining time (pot life) in the coating solution state. 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 added 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 photosensitive layer.

  In the present invention, the dry solid content coating amount of the photosensitive layer itself is preferably formed with a dry solid content coating amount in the range of 0.3 to 10 g per square meter in dry mass, and further in the range of 0.5 to 3 g. It is extremely preferable to exhibit good resolution and to ensure the printing durability of fine line images and fine dot images, and at the same time to greatly improve the ink transportability.

  In the method for producing a photosensitive lithographic printing plate of the present invention, the aqueous photosensitive layer coating solution described above is coated on a support having a hydrophilic surface. When an aluminum plate is used as the support, it is preferable that the surface of the aluminum plate is roughened and hydrophilized by anodizing. Moreover, when a support body is various plastic films, it is preferable that the surface of this plastic film is hydrophilized by providing the following hydrophilic layer.

  The hydrophilic layer preferably contains a water-soluble polymer compound. Examples of the water-soluble polymer compound include gelatin, polyvinyl alcohol, starch, cellulose derivatives, polyacrylic acid derivatives, polyvinyl pyrrolidone and the like, and preferred are gelatin and polyvinyl alcohol.

  As the gelatin, any gelatin can be used as long as it is made from animal collagen, but gelatin made from collagen made from pork skin, cowhide or cow bone is preferred. Further, the type of gelatin is not particularly limited, but lime-processed gelatin, acid-processed gelatin, gelatin derivatives (for example, JP-B Nos. 38-4854, 39-5514, 40-12237, and 42-26345). U.S. Pat.Nos. 2,525,753, 2,594,293, 2,614,928, 2,763,639, 3,118,766, 3,132,945, 3,186,843, 3,332,553, British Patents 861,414, The gelatin derivatives described in No. 1033189 etc. can be used alone or in combination. Further, the gelatin jelly strength (based on PAGI method, Bloom type jelly strength meter) is preferably 150 g or more, particularly preferably 200 g or more.

  As the polyvinyl alcohol, as long as it contains a substantial amount of an unsubstituted vinyl alcohol unit capable of imparting the hydrophilicity necessary for application of the aqueous photosensitive layer coating solution of the present invention, a part thereof is ester, ether, and It may be substituted with acetal. Similarly, a part may contain other copolymerization components. Specific examples of the polyvinyl alcohol include those having a hydrolysis degree of 71 to 100% and a polymerization degree of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA -203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-405, PVA-420, PVA-613 Etc. Examples of the copolymer include 88-100% hydrolyzed polyvinyl acetate or propionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof.

  In addition, when using gelatin or polyvinyl alcohol, other water-soluble polymer compounds can be used in combination. Examples of such water-soluble polymers include natural products such as starch, seaweed mannan, agar, and algae such as sodium alginate, mannan, pectin, tragacanth gum, karaya gum, xanthine gum, guarbin gum, locust bin gum, gum arabic. Plant mucilage such as dextran, glucan, xanthan gum, homopolysaccharide such as levan, microbial mucilage such as heteropolysaccharide such as succinoglucan, pullulan, curdlan and xanthan gum, protein such as glue, casein and collagen , Chitin and derivatives thereof. Semi-natural products (semi-synthetic products) include cellulose derivatives, modified gums such as carboxymethyl guar gum, cultured starches such as dextrin, processed starches such as oxidized starches and esterified starches. . On the other hand, the synthetic products include polyacrylic acid derivatives, polyacrylic acid ester partial saponification products, polymethacrylic acid salts, and polyacrylic acid derivatives such as polyacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, Examples thereof include vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer, styrene / crotonic acid copolymer, and the like.

  When using the above water-soluble polymer compounds other than gelatin and polyvinyl alcohol, it is preferably 100% by mass or less, more preferably 60% by mass or less, and 30% by mass with respect to gelatin and polyvinyl alcohol. The following is more preferable.

  The hydrophilic layer preferably contains an inorganic filler, and the content of the water-soluble polymer compound contained in the hydrophilic layer is preferably 5 to 30% by mass with respect to 100 parts by mass of the total inorganic filler. It is more preferable if it is ˜25 mass%. When the content of the water-soluble polymer compound exceeds 30% by mass, the filler filling density is lowered and sufficient hydrophilicity cannot be imparted, and the soil resistance and the anti-netting property may be lowered in some cases. On the other hand, if it is less than 5% by mass, the handling property of the coating liquid may be lowered, or cracks may occur after the formation of the hydrophilic layer.

  Examples of the inorganic filler contained in the hydrophilic layer include calcium carbonate, magnesium carbonate, zinc oxide, titanium dioxide, barium sulfate, aluminum hydroxide, zinc hydroxide, colloidal silica, pore silica, and kaolin. Titanium dioxide, barium sulfate, and aluminum hydroxide are preferred. Moreover, it is preferable not to use silicon-containing compounds such as colloidal silica, fine pore silica, and kaolin, and the content of these silicon-containing compounds should be 5% by mass or less based on the total inorganic filler in the hydrophilic layer. It is preferably 3% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

  Titanium dioxide preferably used as the inorganic filler may be either a rutile type or an anatase type, and the production method is not limited to either the sulfuric acid method or the chlorine method. You may use them individually or in mixture. Furthermore, from the viewpoint of dispersion stability and other functionality, it is possible to selectively use those subjected to various surface treatments. Examples of commercially available titanium dioxide include SR-1, R-650, R-5N, R-7E, R-3L, A-110, and A-190 from Sakai Chemical Industry Co., Ltd. ) From Taipei R-580, R-930, A-100, A-220, CR-58, Titanium Industry Co., Ltd., Kronos KR-310, KR-380, KA-10, KA -20 etc., Teica Co., Ltd., Titanics JR-301, JR-600A, JR-800, JR-701 etc., DuPont Co., Ltd. Taipure R-900, R-931 etc. are mentioned.

  As barium sulfate, it is preferable to use precipitated barium sulfate produced by adding a sulfate aqueous solution to a barium chlorine solution and chemically precipitating. Precipitated barium sulfate is commercially available, for example, as “Variace” from Sakai Chemical Industry Co., Ltd., having various particle diameters or surface-treated ones, but any of them can be used in the present invention.

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

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

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

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

  The inorganic filler contained in the hydrophilic layer may be one type of filler as long as it is an inorganic filler having the above particle size distribution, but when two or more types are used in combination, the above particle size distribution can be obtained relatively easily. Therefore, it is preferable. Among them, it is preferable to use a combination of an inorganic filler having an average primary particle size of 0.1 μm or more and less than 0.6 μm and an inorganic filler having an average primary particle size of 0.6 μm or more and less than 2.0 μm. You may use an inorganic filler in combination with 3 types and 4 types further. The addition amount of the inorganic filler is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total solid content of the hydrophilic layer.

  The hydrophilic layer preferably contains a hardener. As the hardener used, for example, melamine resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinyl sulfone and the like can be suitably used, but a particularly preferred hardener is divinyl sulfone. The compounding amount of the hardener is preferably 5 to 35% by mass, more preferably 10 to 25% by mass, based on the solid content of the water-soluble polymer compound. As for the method of adding the hardener, there are a method of adding it when producing the coating liquid of the hydrophilic layer, a method of adding it in-line immediately before coating, and any method may be used.

  In order to sufficiently crosslink the hydrophilic layer, for example, 0.5 to 0.5 at a temperature of 30 to 60 ° C., preferably 40 to 50 ° C., between the formation of the hydrophilic layer and the application of the aqueous photosensitive layer coating solution. It is preferable to perform a heating treatment for 10 days, preferably 1 to 7 days. Even if the hydrophilic layer is exposed by the development process after the exposure by such a heating process and is subjected to printing as a non-image part at the time of printing, it is natural as printability, but it is sufficient in terms of scratch resistance. Performance can be expressed.

  The dry solid content of the hydrophilic layer is preferably in the range of 1 to 15 g per square meter, and more preferably in the range of 2 to 10 g for securing water retention and printing durability.

  Examples of the various plastic films used as the support include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, and cellulose nitrate. Typical examples include polyethylene terephthalate and polyethylene naphthalate. Further, before the hydrophilic layer described above is provided, it is preferable that the surface of the film support is subjected to a hydrophilic treatment. Examples of the hydrophilic treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. Is mentioned. As a further hydrophilic treatment, an undercoat layer may be provided on the support in order to enhance adhesion with the hydrophilic layer provided on the support.

  In the photosensitive lithographic printing plate of the present invention, it is also preferable to further provide a protective layer on the photosensitive layer obtained by applying the aqueous photosensitive layer coating solution. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer to further improve exposure sensitivity in the atmosphere. It has a favorable effect of improving. Furthermore, an effect of preventing the photosensitive layer surface from scratches is also expected. Therefore, the properties desired for such a protective layer are low permeability of low molecular weight compounds such as oxygen and excellent mechanical strength, and further, transmission of light used for exposure is not substantially inhibited, and adhesion to the photosensitive layer. It is desirable that it is excellent in that it can be easily removed in the development process after exposure. In the photosensitive lithographic printing plate of the present invention, it is possible to simultaneously remove such a protective layer and an unexposed portion of the photosensitive layer in the course of water development, so that it is not particularly necessary to provide a protective layer removing step. Is a feature. Furthermore, since the polymer contained in the photosensitive layer as described above is water-soluble, moisture in the atmosphere may be absorbed and blocking may occur. However, by providing a protective layer above the photosensitive layer, Such blocking can be eliminated. In addition, when performing scanning exposure using a semiconductor laser or the like, a 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.

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

  As a coating method for coating the undercoat layer, hydrophilic layer, photosensitive layer, protective layer, etc. in the photosensitive lithographic printing plate of the present invention, various known methods can be used. For example, bar coater coating, curtain coating, etc. Examples thereof include coating, blade coating, air knife coating, roll coating, spin coating, and dip coating.

The light source used for exposure for forming an image pattern on the photosensitive lithographic printing plate obtained by the production method of the present invention includes a carbon arc, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a low pressure mercury lamp, a deep UV lamp, a xenon lamp, and a metal halide. Lamps, tungsten lamps, halogen lamps, excimer UV lamps, LED lamps, various fluorescent lamps (white fluorescent lamps, black lights, chemical lights, etc.) can be used. Highly preferred. Examples of the laser light source include a blue-violet semiconductor laser (violet laser), an argon laser, a helium / neon laser, a red LED, a near infrared laser, and an infrared laser. Among them, GaN having a wavelength region of 390 to 430 nm is preferably used from the viewpoint of productivity and image definition. The scanning method may be any of an internal drum system, an external drum system, a planar scanning system, etc., but an internal drum system is preferred. The laser intensity at the plate surface is preferably set to 1~600μJ / cm ^2, particularly preferably in the 30~400μJ / cm ^2.

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

  On the other hand, when the polymer compound having a polymerizable unsaturated bond group has an acid group that is not neutralized such as a carboxyl group or a sulfo group, the developer preferably contains an alkaline agent. Alkaline agents include sodium silicate, potassium silicate, lithium silicate, ammonium silicate, sodium metasilicate, potassium metasilicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, diphosphoric acid Inorganic alkali salts such as sodium, sodium triphosphate, dibasic ammonium phosphate, tribasic ammonium phosphate, sodium borate, potassium borate, ammonium borate, or monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine , Diisopropylamine, monobutylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, etc. Is, they were added, can be used as an alkaline developing solution by adjusting to pH9 above. In addition, it is preferable to add the activator or the like used as the neutral developer to the alkali developer to improve the developability.

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this Example. In addition, unless otherwise indicated, the number of parts and percentage in an Example are mass references | standards.

<Preparation of Comparative Example and Photosensitive Planographic Printing Plate of the Present Invention>
On a polyethylene terephthalate film having a thickness of about 200 μm, a hydrophilic layer coating solution having the following composition was applied by a slide hopper coating method. At that time, the moisture application amount was set in advance to be 35 g / m ² . Immediately after coating, the coating film was gelled with cold air of 1 to 5 ° C., and then dried using a dry air set at 50 ° C. After drying, it was placed in a thermo-hygrostat adjusted to 40 ° C. and 40% RH and heated for 7 days.

<Hydrophilic layer coating solution>
Gelatin (jelly strength 210 g) 1.2 parts Inorganic filler 1: Titanium dioxide 4.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size ≈ 0.3 μm, relative refractive index ≈ 2.04)
Inorganic filler 2: 1.6 parts of barium sulfate (B35, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size≈0.3 μm, relative refractive index≈1.23)
Inorganic filler 3: 0.4 parts of aluminum hydroxide (H42, manufactured by Showa Denko KK, average primary particle size ≈ 1.0 μm, relative refractive index ≈ 1.24)
Dispersant (acrylic acid copolymerized metal salt, 10% solution) 1.0 part Surfactant (POE nonylphenyl ether sulfate, 10% solution) 0.4 part Hardener (divinylsulfone, 5% solution) The total amount was 35 parts with 0 parts water.

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

Solution A having the following composition was prepared.
<Solution A>
Total amount of Compound A and Compound B 6 parts Organoboron salt (BC-7) 2 parts Trihaloalkyl-substituted compound (T-8) 1.5 parts Sensitizing dye (VS-1) 0.05 parts 3-Acryloxypropyl Trimethoxysilane 0.08 parts Ethyl acetate 200 parts

Solution B having the following composition was prepared.
<Solution B>
Water-soluble polymer (SP-2) Average molecular weight 80,000 20 parts Perex OTP (sodium dialkylsulfosuccinate: manufactured by Kao Corporation) 5 parts Ion-exchanged water 300 parts

  Combination of (meth) acrylate compound used as compound A and (meth) acrylate compound used as compound B, (meth) acrylate compound used as compound A in the combination, and (meth) acrylate used as compound B The mass ratio of the compounds is shown in Table 1.

  For the preparation of the aqueous photosensitive layer coating solution, a tabletop vacuum emulsifier PVQ-1D manufactured by Mizuho Kogyo Co., Ltd. is used. And made. The rotation speed of the homomixer was set to 5000 rpm. The solution A and the solution B prepared above were introduced into a vacuum emulsification apparatus, and emulsified and dispersed by high-speed stirring for 20 minutes using a homomixer at room temperature. Thereafter, 0.2 parts of Pigment Blue 15 as a colorant was added and stirred, and the inside of the vacuum emulsifier was depressurized with an aspirator, and the temperature was raised to 50 ° C. under a depressurization condition of 20% of atmospheric pressure, and ethyl acetate was added. Distilled under reduced pressure. From the amount of ethyl acetate collected in the cooler, it was confirmed that all the ethyl acetate used was distilled off from the emulsion in water. Thus, an aqueous photosensitive layer coating solution was prepared.

  A photosensitive layer was formed by applying and drying the aqueous photosensitive layer coating solution on the hydrophilic layer obtained by applying the hydrophilic layer coating solution. The 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 an oven at 80 ° C.

Further, the following protective layers were respectively applied on the photosensitive layer so as to have a dry mass of 2 g / m ² and dried in a dryer at 75 ° C. for 10 minutes. A sex lithographic printing plate was obtained.

<Protective layer prescription>
Polyvinyl alcohol PVA-105 (manufactured by Kuraray Co., Ltd.) 1 part by mass Ion-exchanged water 9 parts by mass

<Exposure / Development>
About each of the photosensitive lithographic printing plates of the present inventions 1 to 13 and Comparative Examples 1 to 6 obtained above, images were exposed in a 5 ° C. environment with a blue-violet semiconductor laser emitting at 405 nm (output 120 mW). Thereafter, the plate was immersed in ion exchange water at 25 ° C. for 15 seconds, the surface having the photosensitive layer / protective layer was rubbed and developed with cellulose sponge, and then dried to obtain a printing plate. The image exposed at this time is an image having a negative positive fine line with a resolution of 2450 dpi and 50 μm, and the exposure energy at which the line widths of the negative positive fine lines after development are matched is obtained as an appropriate exposure value. Described.

<Print stain resistance>
For each of the above-described photosensitive lithographic printing plates of the present inventions 1 to 13 and Comparative Examples 1 to 6, after carrying out forced heating at 40 ° C. for 10 days, the image was exposed in an environment of 5 ° C., and the above development processing In the same manner as described above, development and drying were performed to obtain a printing plate. The printing press plate obtained in this way uses the offset sheet-fed press Heidelberg QM46 as the printing press, New Champion F Gross Purple (S) manufactured by DIC Corporation as the printing ink, and ( Printing was performed using a 0.5% dilution of Astro Mark III manufactured by Nikken Chemical Laboratory. As evaluation, the non-image part of the printing paper surface at the time of printing 8000 sheets was observed carefully, and it determined using the following evaluation criteria. The results are shown in Table 1.
(Double-circle): The stain | pollution | contamination of a non-image part is not seen at all.
○: A thin stain is seen in a part of the non-image area.
Δ: The entire non-image portion is slightly stained.
X: The whole paper surface is dirty.

<Print durability>
For each of the photosensitive lithographic printing plates of the present inventions 1 to 13 and Comparative Examples 1 to 6, after exposing the image in an environment of 5 ° C., development and drying were performed in the same manner as in the development processing to obtain a printing plate. Obtained. The printing press plate obtained in this way uses the offset sheet-fed press Heidelberg QM46 as the printing press, New Champion F gloss ink N made by DIC as the printing ink, and as the dampening solution as Co., Ltd. Printing was performed using a 1% dilution of Astro Mark III manufactured by Nikken Chemical Laboratory. In the plate finishing, a gauge film was used, and the standard 200 μm was set to 300 μm (+100 μm). As an evaluation, the printing paper surface at the start and the printing paper surface at the time of printing 20,000 sheets are compared, and the attenuation factor of the highlight halftone dot portion and the fine defect in the solid portion are 25 times magnifier. And carefully observed and judged using the following evaluation criteria. The results are shown in Table 1.
A: Almost no change is observed in the highlight part and the solid part.
◯: Slight attenuation (attenuation rate of less than 10%) is observed at the highlight portion.
However, no defects are observed in the solid part.
Δ: A clear attenuation (attenuation rate of 10% or more) is observed in the highlight portion.
However, no defects are observed in the solid part.
X: The highlight part is attenuated by 50% or more.
Or abnormalities such as defects are observed in the solid portion.

  From the above results, according to the present invention, it is possible to obtain a photosensitive lithographic printing plate having good printing durability with no reduction in sensitivity in a low-temperature environment and free from printing stains even after long-term storage. I understand.

Claims (1)

  (A) a (meth) acrylate compound having a molecular weight of less than 500 and an equivalent of (meth) acrylate lower than 150, (B) a molecular weight of 500 to 5000, and two or more (meth) acryloyl groups in one molecule A support having a hydrophilic surface, the aqueous photosensitive layer coating solution obtained by emulsifying and dispersing (A) to (C) in water containing at least a compound having (C) a photopolymerization initiator A method for producing a photosensitive lithographic printing plate to be coated thereon.