JP2013205737A - Photosensitive planographic printing plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive planographic printing plate material having a small decrease in sensitivity even if stored over a long period of time.SOLUTION: There is provided a photosensitive planographic printing plate material having a photo-curable photosensitive layer including at least a photopolymerization initiator, a compound having a polymerizable double bond group and a sensitizing dye on a hydrophilic support surface, wherein the photo-curable photosensitive layer is obtained by applying an aqueous coating liquid prepared by mixing dispersion particles of the photopolymerization initiator and dispersion particles of the sensitizing dye onto the support.

Description

  The present invention relates to a photosensitive lithographic printing plate material having a photocurable photosensitive layer on the surface of a hydrophilic support. More specifically, the present invention relates to a photosensitive lithographic printing plate material which is suitable for chemicalless development containing substantially no alkali agent and has excellent storage stability.

  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. A possible system is being developed. 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. As a result, various plate setters equipped with various lasers and photosensitive lithographic printing plate materials suitable for them 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 the normal CTP method, the photosensitive lithographic printing plate material is laser-exposed and the non-image area 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. The costs associated with the purchase and waste liquid treatment impose a great burden on the user. In addition, the pH and temperature of the alkaline developer must be carefully controlled, and handling is extremely complicated. there were.

  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. Further, JP 2003-215801 A (Patent Document 2), JP 2008-265297 A (Patent Document 3) 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 is disclosed.

  Such a photosensitive lithographic printing plate material contains a photopolymerization initiator, a sensitizing dye, a photocrosslinking agent, and the like. Among them, the sensitizing dye is used for giving sensitivity to light having a wavelength of a laser for forming an image portion of the photosensitive lithographic printing plate or for increasing the sensitivity. For example, cyanine dyes disclosed in JP2011-186367A (Patent Document 4), coumarins disclosed in JP-A-8-29973 (Patent Document 5), and sensitizing dyes described in JP200142524A (Patent Document 6). It is disclosed. However, photosensitive lithographic printing plates using these sensitizing dyes are not sufficiently stable over time, and as time passes, decomposition of the sensitizing dye proceeds or aggregation occurs in the photosensitive layer. There has been a need for improvement due to a decrease in sensitivity caused by long-term storage.

JP-A-5-27437 JP 2003-215801 A JP 2008-265297 A JP 2011-186367 A JP-A-8-29973 JP 2001-42524 A

  An object of the present invention is to provide a photosensitive lithographic printing plate material which is suitable for chemicalless development substantially free of an alkali agent and has excellent storage stability.

The above-described problems of the present application are solved by the following invention.
A photosensitive lithographic printing plate material having a photocurable photosensitive layer containing at least a photopolymerization initiator, a compound having a polymerizable double bond group and a sensitizing dye on the surface of a hydrophilic support, A photosensitive lithographic printing plate characterized in that an optical layer is provided by applying an aqueous coating solution prepared by mixing a dispersion of a photopolymerization initiator and a dispersion of a sensitizing dye on a support. material.

  According to the present invention, it is possible to provide a photosensitive lithographic printing plate material which is suitable for chemicalless development substantially free of an alkali agent and has excellent storage stability.

Hereinafter, the present invention will be described in detail.
The photosensitive lithographic printing plate of the present invention has a photocurable photosensitive layer containing at least a photopolymerization initiator, a compound having a polymerizable double bond group, and a sensitizing dye on the surface of a hydrophilic support. The support is made of paper, a synthetic or semi-synthetic polymer film, a metal plate such as aluminum, iron, etc. that can withstand lithographic printing, and has a hydrophilicity that allows the surface to become a non-image area during printing. Can be used. The surface of the substrate can also be coated on one or both sides with one or more polymer films or metal thin films. The surface of these base materials can be surface-treated in order to improve adhesion with the coating layer.

  Particularly preferably used base materials are paper coated with a polyolefin polymer on both sides or one side, a polyester film, a polyester film whose surface is hydrophilized, an aluminum plate subjected to a surface treatment, and the like. These substrates may contain pigments for preventing halation and solid fine particles for improving surface properties. The substrate may be light transmissive so that backside exposure is possible. Moreover, the base material may have an undercoat layer. In that case, for example, an aqueous undercoat composition containing an epoxy compound described in JP-A-60-213942 is exemplified. In order to provide the substrate surface with a hydrophilicity that can be a non-image area during printing, it is preferable to provide a hydrophilic layer described later on the substrate.

  The photocurable photosensitive layer of the present invention contains a sensitizing dye as a compound for sensitizing a photopolymerization initiator described later. As the sensitizing dye, cyanine dyes described in JP-A No. 2011-186367, JP-A Nos. 7-271284 and 8-29973 are disclosed as compounds that increase the sensitivity in the wavelength region of 400 to 430 nm. Coumarin compounds described in JP-A-9-230913, JP-A-2001-42524, etc., JP-A-8-262715, JP-A-8-272096, Carbomerocyanine dyes described in JP-A-9-328505, etc., JP-A-4-194857, JP-A-6-295061, JP-A-7-84863, JP-A-8-220755, Aminobenzylidene ketone color as described in Kaihei 9-80750, JP-A-9-236913, etc. JP-A-4-184344, JP-A-6-301208, JP-A-7-225474, JP-A-7-5585, JP-A-7-281434, JP-A-8-6245, etc. Examples include pyromethine dyes described, styryl dyes described in JP-A-9-80751, and (thio) pyrylium compounds. Of these, cyanine dyes, coumarin compounds or (thio) pyrylium compounds are preferred.

  The photocurable photosensitive layer of the present invention is provided by coating an aqueous coating solution prepared by mixing a dispersion of a photopolymerization initiator and a dispersion of a sensitizing dye on a support. The aqueous coating liquid is a liquid medium component in which water accounts for 50% by mass or more, preferably 80% by mass. As long as the effect of the present invention is not impaired, the liquid medium may contain an organic solvent that is compatible with water, but the organic solvent that dissolves the photopolymerization initiator and the sensitizing dye may not contain substantially. preferable.

  In the present invention, a photopolymerization initiator and a sensitizing dye are separately prepared as dispersions and mixed to prepare a coating solution for the photocurable photosensitive layer. The dispersion method for producing the dispersion of the sensitizing dye is not particularly limited, and a bead mill, a ball mill, a mortar, or the like can be used. The particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 1 μm. Alternatively, a sensitizing dye may be dissolved in an organic solvent in advance to prepare an emulsion in water, and the organic solvent may be removed from the emulsion by distillation to prepare a dispersion in which fine particles are dispersed in water. The preparation of the dispersion using the emulsion in water will be described in detail later.

  1-50 mass% is preferable with respect to a photoinitiator, and, as for content of the sensitizing dye in a photocurable photosensitive layer, 2-20 mass% is more preferable.

  As the photopolymerization initiator contained in the photocurable photosensitive layer of the present invention, conventionally known compounds can be used. For example, trihaloalkyl-substituted compounds (for example, s-triazine compounds and oxadiazole derivatives as trihaloalkyl-substituted nitrogen-containing heterocyclic compounds, trihaloalkylsulfonyl compounds), organic boron salts, hexaarylbiimidazoles, titanocene compounds, thios Examples thereof include compounds and organic peroxides. Among these photopolymerization initiators, trihaloalkyl-substituted compounds and organic boron salts are particularly preferably used. More preferably, a combination of a trihaloalkyl-substituted compound and an organic boron salt is used. High sensitivity can be achieved by combining trihaloalkyl-substituted compounds and organic boron salts, and since the radical species generated by using these in combination can be stabilized, sensitivity can be further improved. Is preferred.

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

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

  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 in the photocurable photosensitive layer as described above is preferably 1 to 50% by mass and more preferably 5 to 30% by mass with respect to the compound having a polymerizable double bond group described later.

  The compound having a polymerizable double bond group contained in the photocurable photosensitive layer of the present invention is a polymer compound having a polymerizable double bond group or a low molecular compound having a polymerizable double bond group. From the viewpoint of photopolymerization efficiency, it is preferable to use a polymer compound having a double bond group and a low molecular compound having a polymerizable double bond group in combination.

  The polymer compound having a polymerizable double bond group will be described. The polymer compound having a polymerizable double bond group is a polymer compound formed by an arbitrary repeating unit, and a polymer compound in which a polymerizable double bond group is bonded to a side chain through an arbitrary linking group. It is. Among them, a polymer compound having a vinyl group as a reactive double bond group is preferably used, and a polymer compound in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via an arbitrary linking group is particularly preferably used. It is done. Further, in order to enable development with an alkaline developer or a neutral developer, it is preferable to introduce a carboxyl group, a sulfonic acid group, a quaternary ammonium group, or the like linked to the main chain via an arbitrary linking group. However, a polymer compound having a sulfonic acid group can be preferably used because of its high developability. The sulfonic acid 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 sulfonic acid group substituted with a vinyl group may be independently bonded to the main chain, or the phenyl group and sulfonic acid group substituted with a vinyl group share part or all of the linking group. You may combine in the form to do.

  In the phenyl group substituted by the vinyl group, the phenyl group may be substituted, and the vinyl group is a halogen atom, 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 double bond group of the present invention may be a polymer comprising only a repeating unit having a phenyl group in which a vinyl group is substituted on the side chain and a repeating unit having a sulfonic acid group. As long as it does not interfere with the effects of the present invention, it may be a polymer into which another repeating unit is further introduced. 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 double bond group of this invention 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.

  Preferred examples of the polymer compound having a polymerizable double bond group of the present invention are shown below, but the present invention is not limited to these examples. The numbers in the exemplified structural formulas represent the mass% of each repeating unit in the copolymer total composition of 100 mass%.

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

  Next, the low molecular weight compound having a polymerizable double bond group used in the present invention will be described. In this case, any low molecular compound having a polymerizable double bond group can be preferably used as long as it is a compound that undergoes polymerization by radicals generated by photolysis of the photopolymerization initiator. Furthermore, when a compound having two or more polymerizable double bond groups in the molecule is used, a crosslinked product is formed as a result of polymerization by radicals. Therefore, a negative photosensitive lithographic printing plate material is used. 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 group Polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. are also used in the same way as various oligomers introduced with That.

  The photocurable photosensitive layer of the present invention preferably contains a silane coupling agent. A photosensitive lithographic plate using a support provided with a hydrophilic layer on a substrate, which is a preferred embodiment of the present invention, can be obtained when the photocurable photosensitive layer contains a silane coupling agent. The printing plate material is particularly preferable because the printing durability is improved without deterioration of the background stain resistance, the anti-screening property, the ink detachment property, and the like.

  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.

  As a quantity of the silane coupling agent which a photocurable photosensitive layer contains, 0.2-20 mass% is preferable with respect to the compound which has a polymerizable double bond group which a photocurable photosensitive layer contains, 0.5 10 mass% is more preferable.

  In the photocurable photosensitive layer 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. Such a polymerization inhibitor makes it possible to prolong the lifetime of the sensitivity maintenance time (pot life) in the coating solution state used when the photocurable photosensitive layer is applied. 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 photocurable photosensitive layer.

  The coating solution for the photocurable photosensitive layer of the present invention contains a dispersion of the photopolymerization initiator described above. The dispersion of the photopolymerization initiator can be prepared in the same manner as the dispersion of the sensitizing dye. Further, a compound that is soluble in an organic solvent such as a photopolymerization initiator and a low-molecular compound having a polymerizable double bond group is dissolved in the organic solvent, and then an emulsion in water is produced. A dispersion in which fine particles are dispersed in water may be prepared and used.

  In producing a dispersion of a sensitizing dye, an emulsion in water, a dispersion of a photopolymerization initiator, and an emulsion in water, a dispersant can be used to improve dispersion efficiency and dispersion stability. As the dispersant, an anionic surfactant is preferably used. In particular, when preparing an underwater emulsion of a photopolymerization initiator, by emulsifying and dispersing in water in the presence of an anionic surfactant, an underwater emulsion that can be stably maintained in an emulsified dispersion state even when exposed to a certain high temperature is obtained. . 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, sodium octyl alcohol sulfate, and lauryl. Sodium alcohol sulfate, higher alcohol sulfates such as ammonium lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, sodium butylnaphthalene sulfonate, Alkylnaphthalene sulfonates such as sodium isopropyl naphthalene sulfonate, Alkyl diphenyl ether disulfonates such as sodium ruether disulfonate, alkyl phosphate esters such as sodium lauryl phosphate and sodium stearyl phosphate, polyethylene oxide adduct of sodium lauryl ether sulfate, polyethylene oxide adduct of ammonium lauryl ether sulfate, triethanol lauryl ether sulfate Polyethylene oxide adducts of alkyl ether sulfates such as polyethylene oxide adducts of amines, polyethylene oxide adducts of alkyl phenyl ether sulfates such as polyethylene oxide adducts of sodium nonylphenyl ether sulfate, polyethylene oxides of sodium lauryl ether phosphate Polyethylene oxide adducts of alkyl ether phosphates such as 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 preferable because of the most improved dispersion stability.

  In preparation of an emulsion in water of a sensitizing dye or a photopolymerization initiator, the emulsion dispersion stability is further improved by adding the above-described polymer compound having a polymerizable double bond group and a sulfonate group. Since the polymer compound is water-soluble, it may be added during emulsification dispersion of the sensitizing dye or photopolymerization initiator, or may be added after emulsification dispersion. The dispersion particle diameter in water is remarkably reduced and dispersed in the form of extremely fine droplets and fine particles, which is more preferable because problems such as sedimentation or levitation over time can be suppressed. 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 a sensitizing dye or photopolymerization initiator in water, a sensitizing dye or photopolymerization initiator and, if necessary, a low molecular compound having a polymerizable double bond group in either of the former two. In addition, a solution using an organic solvent capable of dissolving or dispersing them is prepared and mixed with water, and then an anionic surfactant or a polymerizable double bond group and a sulfonate group are added. A method in which a molecular compound is added and emulsified and dispersed is preferred. However, when the low molecular weight compound having a polymerizable double bond group is a liquid and the photopolymerization initiator is dissolved in the liquid and the mixture of both is liquid, the mixture of the two is used without using an organic solvent. Can be emulsified and dispersed in water. Moreover, you may produce separately the emulsion in water of the low molecular compound which has a sensitizing dye, a photoinitiator, and a polymerizable double bond group, respectively.

  The organic solvent that can be used in the emulsification dispersion may be any organic solvent that is liquid at room temperature and can dissolve or disperse the sensitizing dye or the photopolymerization initiator. 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 and 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 sensitizing dye or the photopolymerization initiator 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, a method for producing an underwater emulsion in which the sensitizing dye or the photopolymerization initiator of the present invention is dispersed will be specifically described.

  A solution in which the sensitizing dye or the photopolymerization initiator is dissolved or dispersed is prepared using the organic solvent such as ethyl acetate. A known stirring device capable of high-speed shearing such as a homomixer or a homogenizer when added to water containing an anionic surfactant or a polymer compound having a polymerizable double bond group and a sulfonate group An emulsified solution in water can be prepared by emulsifying and dispersing the composition. The organic solvent may contain other water-insoluble compounds contained in the coating solution for coating the photocurable photosensitive layer of the present invention, and the water used as the dispersion medium may be contained in the coating solution. Other water soluble compounds 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. An aqueous coating solution for coating the photocurable photosensitive layer of the present invention is prepared by mixing the dispersion of the photopolymerization initiator and the dispersion of the sensitizing dye separately prepared as described above.

  As other elements constituting the photocurable photosensitive layer of the photosensitive lithographic printing plate material of the present invention, various colorants are preferably added for the purpose of improving visibility. As a colorant added for such purposes, an aqueous dispersion of a color pigment can be most preferably used. Examples of water-based dispersions of such pigments include various, black, blue, red, green, yellow, and other pigments that do not act as sensitizing dyes dispersed in water in the presence of various water-soluble dispersants. The material is usable. In particular, carbon black, phthalocyanine blue, phthalocyanine green, and the like as pigments are particularly preferred because they are readily available and relatively easy to disperse in water. Examples of dispersants that can be used to disperse these pigments in water include water-soluble nonionic surfactants having an oxyethylene group such as polyethylene glycol and polypropylene glycol, polyacrylic acid, and polyvinylpyrrolidone. , Polystyrene-maleic acid half ester copolymer, polystyrene-maleic acid copolymer, and other various water-soluble polymers. Such a dispersant is preferably contained in a range of 5 to 50 parts by mass with respect to 100 parts by mass of the color pigment. Furthermore, when using a color pigment, it is preferable that it is contained in 1-30 mass parts with respect to 100 mass parts of compounds which have a polymerizable double bond.

  Regarding the dry solid content coating amount of the photocurable photosensitive layer of the present invention, it is preferably formed in the range of 0.3 to 10 g per square meter by dry mass, and more preferably in the range of 0.5 to 3 g. It is more preferable for achieving a high resolution and ensuring the printing durability of a fine line image or a fine halftone dot image, and at the same time greatly improving the ink transportability. Arbitrary additives may be added to the coating solution used for coating the photocurable photosensitive layer in order to improve various properties as a photosensitive lithographic printing plate material.

  In the photosensitive lithographic printing plate material of the present invention, it is also preferable to further provide a protective layer on the above-described photocurable photosensitive layer. 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, the effect which prevents the photocurable photosensitive layer surface from a damage | wound is also anticipated. 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. 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 such an unexposed portion of the protective layer and the photocurable photosensitive layer in the course of chemicalless development. It is the feature that it is not necessary to provide. Furthermore, since the polymer contained in the photocurable photosensitive layer as described above is water-soluble, it absorbs moisture in the atmosphere and causes blocking, or causes problems such as sensitivity change during storage. In some cases, such a problem of blocking or sensitivity change can be improved 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 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 photocurable photosensitive layer using various known coating methods.

  The hydrophilic layer preferably contains gelatin as a resin binder. As the gelatin used for the hydrophilic layer, 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, 3,186,846, 3,332,553, British Patents 861,414, 1031189 etc.) can be used alone or in combination. The gelatin strength (PAGI method, by Bloom jelly strength meter) is preferably 150 g or more, particularly preferably 200 g or more.

  The hydrophilic layer can further contain another water-soluble polymer as a resin binder. 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, caraya gum, xanthine gum, guarbin gum, locust bin gum, gum arabic, etc. Vegetative mucilage, dextran, glucan, xanthan gum, homopolysaccharides such as levan, microbial mucilage such as succinoglucan, pullulan, curdlan, and heteropolysaccharide such as xanthan gum, glue, unmodified seratin, casein and collagen And proteins such as 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, synthetic products include polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl-modified polyvinyl alcohol, modified polyvinyl alcohols such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, polyacrylates, and polyacrylate ester partial saponified products. , Polymethacrylic acid derivatives and polymethacrylic acid derivatives such as polymethacrylic acid salts and polyacrylamides, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, vinylpyrrolidone / vinyl acetate copolymer, carboxyvinyl polymer, styrene / maleic acid copolymer Examples thereof include a polymer and a styrene / crotonic acid copolymer. The amount of these water-soluble polymers used is preferably 30% by mass or less based on gelatin.

  The hydrophilic layer preferably contains an inorganic filler, and the content of the resin binder contained in the hydrophilic layer is preferably 5 to 30% by mass, and 10 to 25% by mass with respect to 100 parts by mass of the total inorganic filler. % Is more preferable. If it exceeds 30% by mass, the filler filling density is lowered and sufficient hydrophilicity cannot be imparted, and the soil resistance and the net resistance may be lowered. On the other hand, if it is less than 5% by mass, the handling property of the coating solution may be lowered, or cracking 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 hydrophilic layer preferably contains a crosslinking agent. As the crosslinking agent to be 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 crosslinking agent is divinyl sulfone. The blending amount of the crosslinking agent is preferably 5 to 35% by mass, more preferably 10 to 25% by mass, based on the solid content of the hydrophilic binder. As for the method of adding the crosslinking agent, there are a method of adding the hydrophilic layer coating liquid when it is manufactured, a method of adding it in-line immediately before coating, and the like.

  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 photocurable photosensitive layer. 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.

  When applying an undercoat layer, a hydrophilic layer, a photocurable photosensitive layer, a protective layer, etc. in the photosensitive lithographic printing plate material of the present invention, a coating solution of a composition comprising the above-described elements on a substrate Is applied and dried. Various known methods can be used as the coating method, and examples thereof include bar coater coating, curtain coating, blade coating, air knife coating, roll coating, spin coating, and dip coating.

As a light source used for exposure for forming an image pattern on the photosensitive lithographic printing plate material of the present invention, 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, a metal halide lamp, a tungsten lamp, Although a halogen lamp, excimer UV lamp, LED lamp, various fluorescent lamps (white fluorescent lamp, black light, chemical light, etc.) can be used, scanning exposure with a laser is very preferable in terms of plate making efficiency. Examples of the laser light source include a blue-violet semiconductor laser (violet laser), an argon laser, a helium / neon laser, a red LED, a near infrared laser, and an infrared laser. Among them, GaN having a wavelength region of 390 to 430 nm is preferably used from the viewpoint of productivity and image definition. The scanning method may be any of an internal drum system, an external drum system, a planar scanning system, etc., but an internal drum system is preferred. The laser intensity at the plate surface is preferably set to 1~600μJ / cm ^2, particularly preferably in the 30~400μJ / cm ^2.

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

  On the other hand, when the compound having a polymerizable double bond has an acid group that is not neutralized such as a carboxyl group or a sulfo group, the developer preferably contains an alkali 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.

  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 1-5)
A hydrophilic layer coating solution having the following composition was applied on a polyethylene terephthalate film having a thickness of about 200 μm by a slide hopper coating method. At that time, the 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, the substrate having a hydrophilic surface was completed by putting it in a thermo-hygrostat adjusted to 40 ° C. and 40% RH and heating for 7 days.

<Hydrophilic layer coating solution>
Gelatin (alkali-treated gelatin made from bovine bone ossein) 1.2 parts Titanium dioxide 4.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd.)
1.6 parts of barium sulfate (B35, manufactured by Sakai Chemical Industry Co., Ltd.)
0.4 parts of aluminum hydroxide (H42, Showa Denko KK)
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.

<Preparation of photocurable photosensitive layer coating solution>
Liquid compositions A to C having the following compositions were prepared.
<Liquid composition A>
Ion-exchanged water 100 parts Water-soluble polymer (SP-2) 5.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 3.0 parts (Perex OT-P: manufactured by Kao Corporation)
Colorant (Pigment Blue 15) 0.2 part

<Liquid composition B>
Trimethylolpropane triacrylate 6.0 parts Photopolymerization initiator (BC-7) 2.0 parts Trihaloalkyl-substituted compound (T-8) 1.5 parts 3-acryloxypropyltrimethoxysilane 0.5 parts Ethyl acetate 200 Part was added and dissolved.

<Liquid composition C>
Ion-exchanged water 200 parts Sensitizing dye in Table 1 0.05 part Water-soluble polymer (SP-2) 15.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 2.0 parts (Perex OT-P: Kao ( Made by Co., Ltd.)
The sensitizing dye was added in advance after finely reducing the particle size to 1 μm or less with a ball mill.

  A Mizuho Kogyo Co., Ltd. tabletop vacuum emulsifier PVQ-1D, which is equipped with a homomixer in an airtight container and capable of distilling off the solvent while heating under reduced pressure, was used for producing the emulsion in water. Liquid composition A is charged into a vacuum emulsifier and the rotational speed of the homomixer is set to 5000 rpm. Liquid composition B is charged into the vacuum emulsifier and emulsified and dispersed by high-speed stirring of the homomixer at room temperature for 20 minutes. went. Thereafter, the inside of the vacuum emulsification apparatus was decompressed using an aspirator, the temperature was raised to 50 ° C. under a decompression condition of 20% of atmospheric pressure, and ethyl acetate was distilled off under reduced pressure to obtain a dispersion of a photopolymerization initiator. . 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. Thereafter, the liquid composition C, which is a dispersion of sensitizing dyes, was put into a vacuum emulsifier, and stirred for 1 minute with a homomixer to obtain a photocurable photosensitive layer coating solution.

  The photocurable photosensitive layer coating solution obtained above was applied onto the hydrophilic layer of the support and dried to form a photocurable photosensitive layer. 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 an oven at 80 ° C.

  Further, the following protective layers were respectively applied on the photocurable photosensitive layer so that the dry thickness was 1.5 μm, and dried for 10 minutes in a dryer at 75 ° C., and the photosensitive lithographic printing plates of Examples 1 to 5 Obtained material.

<Protective layer coating solution>
Polyvinyl alcohol PVA-103 (manufactured by Kuraray Co., Ltd.) 1.0 part Ion exchange water 9.0 parts

(Comparative Examples 1-5)
A photocurable photosensitive layer coating solution having the following composition was prepared. This was coated on the hydrophilic layer of the support with a wire bar so that the solid content was 1.6 g / m ² and dried at 50 ° C. for 2 minutes. On top of that, the protective layer coating solution having the above composition was applied onto the photocurable photosensitive layer so that the dry thickness was 1.5 μm, and dried in a dryer at 75 ° C. for 10 minutes. Comparative Examples 1 to 5 A photosensitive lithographic printing plate material was obtained.

<Organic solvent-based photocurable photosensitive layer coating solution>
Trimethylolpropane triacrylate 6.0 parts Photopolymerization initiator (BC-7) 2.0 parts Trihaloalkyl-substituted compound (T-8) 1.5 parts Sensitizing dyes in Table 1 0.05 parts 3-Acryloxypropyl Trimethoxysilane 0.5 part Polymer (SP-2) 20.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 5.0 parts (Perex OT-P: manufactured by Kao Corporation)
Colorant (Pigment Blue) 0.2 part 1,3-dioxolane 300 parts

(Comparative Examples 6 to 10)
<Preparation of photocurable photosensitive layer coating solution>
Liquid compositions D and E having the following compositions were prepared.
<Liquid composition D>
Ion-exchanged water 300 parts Water-soluble polymer (SP-2) 20.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 5.0 parts (Perex OT-P: manufactured by Kao Corporation)
Colorant (Pigment Blue 15) 0.2 part

<Liquid composition E>
Trimethylolpropane triacrylate 6.0 parts Photopolymerization initiator (BC-7) 2.0 parts Trihaloalkyl-substituted compound (T-8) 1.5 parts 3-acryloxypropyltrimethoxysilane 0.5 parts Table 1 Sensitizing dye 0.05 part 200 parts of ethyl acetate was added and dissolved.

  Liquid composition D is charged into vacuum emulsifier PVQ-1D and the rotation speed of the homomixer is set to 5000 rpm. Liquid composition E is charged into the vacuum emulsifier and stirred at high speed for 20 minutes at room temperature. Emulsion dispersion was performed. Thereafter, the inside of the vacuum emulsification apparatus is decompressed using an aspirator, the temperature is raised to 50 ° C. under a decompression condition of 20% of atmospheric pressure, and ethyl acetate is distilled off under reduced pressure to obtain a photocurable photosensitive layer coating solution. . From the amount of ethyl acetate collected in the cooler, it was confirmed that all the ethyl acetate used was distilled off from the emulsion in water.

  The photocurable photosensitive layer coating solution obtained above was applied in the same manner as in Examples 1 to 5, and a protective layer was provided in the same manner as in Examples 1 to 5 to obtain photosensitive lithographic printing plate materials of Comparative Examples 6 to 10. It was.

<Exposure / Development>
The photosensitive lithographic printing plate material obtained above, while changing the exposure energy using the emitted blue-violet semiconductor laser (output 120 mW) to the exposure light source 405nm from 50μJ / cm ² by ^{10μJ / cm 2, 300μJ / cm} 2 A negative positive image of 50 μm was exposed as a test chart image at a resolution of 2450 dpi. After the exposure, the plate was immersed in 30 ° C. ion exchange water for 15 seconds, and the surface having the photocurable photosensitive layer / protective layer was rubbed and developed with cellulose sponge, and then dried to prepare a printing plate. The exposure energy at which the thickness of the negative line and the positive line of the printing plate coincided with each other was determined as the optimum exposure value.

<Storage stability>
The light-sensitive lithographic printing plate obtained above is shielded from light and stored at 40 ° C. and 50% relative humidity for 2 weeks, 4 weeks, 6 weeks, and 8 weeks. The exposure value was determined. Table 1 shows the optimum exposure value after the storage.

  From the above results, it can be seen that the present invention can provide a photosensitive lithographic printing plate material whose photosensitivity does not change even after long-term storage.

Claims (1)

  A photosensitive lithographic printing plate material having a photocurable photosensitive layer containing at least a photopolymerization initiator, a compound having a polymerizable double bond group and a sensitizing dye on the surface of a hydrophilic support, A photosensitive lithographic printing plate characterized in that an optical layer is provided by applying an aqueous coating solution prepared by mixing a dispersion of a photopolymerization initiator and a dispersion of a sensitizing dye on a support. material.