JP2008292910A - Photosensitive lithographic printing plate material for water development and method for producing lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate material for water development which can be developed with water and excels in running properties in development processing with water, and a method for producing a lithographic printing plate using the same. <P>SOLUTION: The photosensitive lithographic printing plate material for water development has on a support a photosensitive layer containing (A) a photopolymerization initiator, (B) a binder, (C) a polymerizable compound containing an ethylenically unsaturated bond and (D) a sensitizing dye and has a protective layer containing polyvinyl alcohol on the photosensitive layer, wherein the photosensitive layer contains a water-soluble high molecular compound as the binder (B) and at least one of the photosensitive layer and the protective layer contains a preservative. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive lithographic printing plate material used in a so-called computer-to-plate (hereinafter referred to as “CTP”) system, and in particular, exposure with a laser beam having a wavelength of 350 to 450 nm. The present invention relates to a photosensitive lithographic printing plate material suitable for the above and a method for producing a lithographic printing plate using the same.

  In recent years, CTP recording digital image data directly on a photosensitive printing plate with a laser light source has been developed and is being put to practical use in the technology for producing printing plates for offset printing.

  Among these, in the field of printing that requires relatively high printing durability, it is necessary to use a printing plate material having a negative photosensitive layer having an image recording layer containing a polymerizable compound on an aluminum support. Are known.

  On the other hand, as a photosensitive lithographic printing plate for CTP which records digital data with a laser, for example, photopolymerization containing titanocene which is a polymerization initiator described in JP-A-9-80750 and JP-A-10-101719 and a specific dye. Those having a photosensitive layer are known. However, since these photosensitive lithographic printing plates use a relatively long-wavelength visible light source as a light source, it is necessary to perform plate-making work for preparing the printing plate under a safe light of a dark red light. There was a demand for being able to handle under a brighter yellow light (lighting room).

  In addition, high-power and small-sized lasers such as blue-violet lasers having emission wavelengths at short wavelengths can be obtained relatively easily, and by developing photosensitive lithographic printing plates suitable for these laser wavelengths, The use of a photopolymerization type photosensitive lithographic printing plate material corresponding to laser exposure in the 350 nm to 450 nm region has been proposed (see, for example, Patent Document 1).

  However, these printing plate materials require a wet development process such as an alkaline aqueous solution after exposure.

  On the other hand, as a printing plate material used in the CTP system, there is a printing plate material that does not require a development treatment with a processing solution containing a special agent (for example, alkali, acid, solvent, etc.) and can be applied to a conventional printing press. For example, there is known a printing plate material called a processless type printing plate material that is developed at an initial stage of printing on a printing press and does not require a development step after image exposure.

  As a processless type printing plate material, for example, a photosensitive lithographic printing plate material in which a photopolymerization type photosensitive layer has a water-soluble binder resin and a non-image area is removed by dampening water on a printing machine is known. (See Patent Documents 2 and 3).

Such a photosensitive lithographic printing plate material can be developed only with water, and development with an alkaline developer having a high pH is not required. However, when such a photosensitive lithographic printing plate material is processed with a large amount of printing plate material using water as a developer, a lot of sludge, soot, etc. are generated in the water used as the developer. There were problems such as seemingly causing stains on the printing plate.
JP 2003-21901 A JP 2006-328661 A JP 2006-343745 A

  An object of the present invention is to provide a photosensitive lithographic printing plate material for water development, which can be developed with water and has excellent running characteristics of the development treatment with water, and a method for producing a lithographic printing plate using the same. is there.

The above object of the present invention is achieved by the following configurations.
1. On the support, (A) a photopolymerization initiator, (B) a binder, (C) a polymerizable ethylenic double bond-containing compound and (D) a sensitizing dye-containing photosensitive layer, In the photosensitive lithographic printing plate material for water development having a protective layer containing polyvinyl alcohol on the photosensitive layer, the photosensitive layer contains a water-soluble polymer as the binder (B), and the photosensitive layer and the photosensitive layer A photosensitive lithographic printing plate material for water development, wherein at least one of the protective layers contains a preservative.
2. 2. The photosensitive lithographic printing plate material for water development according to 1, wherein the preservative is an isothiazoline derivative.
3. 3. The water development according to 1 or 2, wherein the (C) polymerizable ethylenic double bond-containing compound is a reaction product of the following compounds (C1), (C2) and (C3): Photosensitive lithographic printing plate material.
(C1) a compound containing at least one ethylenic double bond and one hydroxyl group in the molecule (C2) a diisocyanate compound (C3) a diol compound having a tertiary amine structure in the molecule, or an intramolecular 3. A compound having one secondary amine structure and one hydroxyl group 4. The photosensitive lithographic printing plate material for water development according to any one of 1 to 3, wherein the water-soluble polymer compound is a polymer compound having vinylpyrrolidone as a constituent monomer unit.
5. A method for preparing a lithographic printing plate, comprising subjecting the photosensitive lithographic printing plate material for water development described in 5.1 to 4 to image exposure, heat treatment, and development treatment with water in this order.
A method for producing a lithographic printing plate, characterized in that the lithographic printing plate obtained by the method for producing a lithographic printing plate described in 6.5 is further treated with a plate surface protective agent containing a water-soluble resin and a surfactant.
7). The method for preparing a lithographic printing plate as described in 5 or 6, wherein the image exposure is performed by a laser having an emission wavelength of 370 nm or more and 420 nm or less.

  According to the above-described configuration of the present invention, the photosensitive lithographic printing plate material for water development and the lithographic printing plate using the same can be developed with water, have excellent printing durability, and have excellent running characteristics of development processing with water. A manufacturing method can be provided.

  The present invention is described in detail below.

  The present invention has a photosensitive layer containing (A) a photopolymerization initiator, (B) a binder, (C) an ethylenically unsaturated bond-containing compound and (D) a sensitizing dye on a support, In the photosensitive lithographic printing plate material for water development having a protective layer containing polyvinyl alcohol on the photosensitive layer, the photosensitive layer contains a water-soluble binder resin as the binder (B), and the photosensitive layer and the protective layer At least one layer contains a preservative.

  In the present invention, by incorporating a preservative in the photosensitive layer or the protective layer, development with water is possible, the printing durability is excellent, and the running characteristics of the development processing with water are excellent. Printing plate material can be provided.

  In the present invention, at least one of the photosensitive layer and the protective layer contains a preservative.

  The preservative according to the present invention is a compound having a bactericidal and antifungal action and a mixture thereof. Examples of the preservative include parabens (methyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate), benzoic acid. And salts thereof (for example, sodium benzoate), sorbic acid and its salts (for example, potassium sorbate), propionic acid and its salts (for example, sodium propionate), ethanol, benzyl alcohol, cresol, chlorocresol, isothiazolinone compounds ( For example, a mixture of chloromethylisothiazolinone / methylisothiazolinone), 2-bromo-2-nitropropane-1,3-diol, and 1,2-benzisothiazol-3 (2H) -one. An antiseptic can be added to prevent mold generation. Among these, isothiazolinone compounds are preferable, and a mixture of chloromethylisothiazolinone / methylisothiazolinone is particularly preferable.

  The content of the preservative is preferably 0.001% by mass to 3% by mass and particularly preferably 0.01% by mass to 1.5% by mass with respect to the photosensitive layer or the protective layer.

  A photosensitive layer and a protective layer containing a preservative can be obtained by adding a preservative to a coating solution for forming the photosensitive layer and the protective layer, coating the photosensitive layer and the protective layer, and drying.

  The photosensitive layer and protective layer according to the present invention will be described below.

(Photosensitive layer)
((A) polymerization initiator)
The polymerization initiator according to the present invention is capable of initiating polymerization of an ethylenic double bond-containing compound that can be polymerized by image exposure. Examples of the polymerization initiator include titanocene compounds and monoalkyltriaryl borate compounds. Iron arene complex compounds, polyhalogen compounds, and biimidazole compounds are preferably used, and among these, biimidazole compounds are particularly preferably used.

  A biimidazole compound is a derivative of biimidazole, and examples thereof include compounds described in JP-A No. 2003-295426.

  In the present invention, a hexaarylbiimidazole (HABI, triaryl-imidazole dimer) compound can be preferably used as the biimidazole compound.

  Processes for the production of HABIs are described in DE 1,470,154 and their use in photopolymerizable compositions is described in EP 24,629, EP 107,792, US 4,410,621, EP 215,453 and DE 3, 211 and 312.

  Preferred derivatives are, for example, 2,4,5,2 ′, 4 ′, 5′-hexaphenylbiimidazole, 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetraphenylbiimidazole. Imidazole, 2,2'-bis (2-bromophenyl) -4,5,4 ', 5'-tetraphenylbiimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,5,4' , 5'-tetraphenylbiimidazole, 2,2'-bis (2-chlorophenyl) -4,5,4 ', 5'-tetrakis (3-methoxyphenyl) biimidazole, 2,2'-bis (2- Chlorophenyl) -4,5,4 ', 5'-tetrakis (3,4,5-trimethoxyphenyl) -biimidazole, 2,5,2', 5'-tetrakis (2-chlorophenyl) -4,4 ' -Bis (3,4-dimethyl) Xylphenyl) biimidazole, 2,2'-bis (2,6-dichlorophenyl) -4,5,4 ', 5'-tetraphenylbiimidazole, 2,2'-bis (2-nitrophenyl) -4,5 , 4 ', 5'-tetraphenylbiimidazole, 2,2'-di-o-tolyl-4,5,4', 5'-tetraphenylbiimidazole, 2,2'-bis (2-ethoxyphenyl) -4,5,4 ', 5'-tetraphenylbiimidazole and 2,2'-bis (2,6-difluorophenyl) -4,5,4', 5'-tetraphenylbiimidazole, The compound can be obtained as a commercial product.

  The content of the biimidazole compound is preferably 0.05% by mass to 20.0% by mass and particularly preferably 1.0% by mass to 10.0% by mass with respect to the photosensitive layer. The content ratio of the compound represented by the general formula (1) and the biimidazole compound (pigment / biimidazole (mass ratio)) is preferably 0.01 to 20, and particularly preferably 0.1 to 10.

  Examples of titanocene compounds include compounds described in JP-A-63-41483 and JP-A-2-291. More preferred specific examples include bis (cyclopentadienyl) -Ti-di-chloride, bis (Cyclopentadienyl) -Ti-bis-phenyl, bis (cyclopentadienyl) -Ti-bis-2,3,4,5,6-pentafluorophenyl, bis (cyclopentadienyl) -Ti-bis -2,3,5,6-tetrafluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4,6-trifluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,6 -Difluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4-difluorophenyl, bis (methylcyclopentadienyl) -Ti-bis- , 3,4,5,6-pentafluorophenyl, bis (methylcyclopentadienyl) -Ti-bis-2,3,5,6-tetrafluorophenyl, bis (methylcyclopentadienyl) -Ti-bis -2,6-difluorophenyl (IRUGACURE 727L: manufactured by Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,6-difluoro-3- (py-1-yl) phenyl) titanium (IRUGACURE 784: Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,4,6-trifluoro-3- (pyridin-1-yl) phenyl) titanium bis (cyclopentadienyl) -bis (2, 4,6-trifluoro-3- (2-5-dimethylpy-1-yl) phenyl) titanium and the like It is below.

  Examples of the monoalkyl triaryl borate compound include compounds described in JP-A-62-150242 and JP-A-62-143044, and more preferable specific examples include tetra-n-butylammonium / n-butyrate. Linaphthalen-1-yl-borate, tetra-n-butylammonium / n-butyl-triphenyl-borate, tetra-n-butylammonium / n-butyl-tri- (4-tert-butylphenyl) -borate, tetra-n -Butylammonium n-hexyl rootri- (3-chloro-4-methylphenyl) -borate, tetra-n-butylammonium n-hexyl rootri- (3-fluorophenyl) -borate and the like.

  Examples of the iron arene complex compound include compounds described in JP-A-59-219307. More preferred specific examples include η-benzene- (η-cyclopentadienyl) iron hexafluorophosphate, η-cumene. -(Η-cyclopentadienyl) iron hexafluorophosphate, η-fluorene- (η-cyclopentadienyl) iron hexafluorophosphate, η-naphthalene- (η-cyclopentadienyl) iron hexafluorophosphate, η- Examples include xylene- (η-cyclopentadienyl) iron hexafluorophosphate, η-benzene- (η-cyclopentadienyl) iron tetrafluoroborate.

  As the polyhalogen compound, a compound having a trihalogenmethyl group, a dihalogenmethyl group or a dihalomethylene group is preferably used, and in particular, the halogen compound represented by the following general formula (1) and the above group is substituted with an oxadiazole ring. A compound is preferably used.

  Among these, a halogen compound represented by the following general formula (2) is particularly preferably used.

Formula (1) R ¹ —CY ₂ — (C═O) —R ²
In the formula, R ¹ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an acyl group, an alkylsulfonyl group, an arylsulfonyl group, an iminosulfonyl group, or a cyano group. R ² represents a monovalent substituent. R ¹ and R ² may be bonded to form a ring. Y represents a halogen atom.

Formula (2) CY ₃ — (C═O) —X—R ³
In the formula, R ³ represents a monovalent substituent. X represents —O— or —NR ⁴ —. R ⁴ represents a hydrogen atom or an alkyl group. R ³ and R ⁴ may be bonded to form a ring. Y represents a halogen atom. Among these, those having a polyhalogenacetylamide group are particularly preferably used.

  A compound in which a polyhalogen methyl group is substituted on the oxadiazole ring is also preferably used. Furthermore, oxadiazole compounds described in JP-A Nos. 5-34904 and 8-240909 are also preferably used.

  In addition, any polymerization initiator can be used in combination. For example, J. et al. Carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo, diazo compounds, halogen compounds, and photoreductive dyes as described in Chapter 5 of “Light Sensitive Systems” by J. Kosar Etc. More specific compounds are disclosed in British Patent 1,459,563.

  That is, as the polymerization initiator that can be used in combination, the following can be used.

  Benzoin derivatives such as benzoin methyl ether, benzoin-i-propyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4′-bis (dimethyl) Benzophenone derivatives such as amino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-i-propylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; N-methylacridone, N-butylacridone and the like In addition to α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone and uranyl compounds, JP-B-59-1281, 61-9621 and JP-A-60-60104 Triazine derivatives; organic peroxides described in JP-A-59-1504 and JP-A-61-243807; JP-B-43-23684, JP-A-44-6413, JP-A-44-6413, JP-A-47-1604, and US patents Diazonium compounds described in US Pat. No. 3,567,453; organic azide compounds described in US Pat. Nos. 2,848,328 and 2,852,379 and 2,940,853; O-quinonediazides described in JP-A Nos. 13109, 38-18015 and 45-9610; JP-B-55-39162, JP-A-59-14023 and “Macromolecules”, Vol. 10, 1307 Various onium compounds described on page 1977; azo compounds described in JP-A-59-142205 Compound: JP-A-1-54440, European Patents 109,851, 126,712 and “Journal of Imaging Science (J. Imag. Sci.)”, Vol. 30, 174 (1986) (Oxo) sulfonium organoboron complexes described in Japanese Patent Application Nos. 4-56831 and 4-89535; “Coordination Chemistry Review”, 84, 85-277 (1988) ) And transition metal complexes containing a transition metal such as ruthenium described in JP-A-2-182701; 2,4,5-triarylimidazole dimer described in JP-A-3-209477; carbon tetrabromide, JP Organic halogen compounds described in JP-A-59-107344, etc.

  The content of the polymerization initiator according to the present invention (total amount of polymerization initiator) is preferably 0.05% by mass to 20.0% by mass, particularly 1.0% by mass to 10.0% by mass with respect to the photosensitive layer. preferable.

((B) binder)
The binder according to the present invention can carry the constituent components contained in the photosensitive layer, and the photosensitive layer contains a water-soluble polymer compound as the binder.

(Water-soluble polymer compound)
The water-soluble polymer compound is a compound having a solubility in water (g number dissolved in water 100 at 25 ° C.) of 0.1 or more and a molecular weight (mass average) of 500 or more.

  Examples of water-soluble polymer compounds include polyvinyl alcohols having various saponification degrees, polymers of hydroxystyrene and copolymers thereof, polyamide resins, copolymers of polyvinylpyrrolidone and vinylpyrrolidone, polyethylene oxide, polyethyleneimine, and polyacrylic. Examples include acid amide, corn starch, mannan, pectin, agar, dextran, pullulan, glue, hydroxymethylcellulose, alginic acid, carboxymethylcellulose, sodium polyacrylate, and the like.

  As the water-soluble polymer compound, a polymer compound having a nonionic hydrophilic group is particularly preferably used.

  The molecular weight is preferably in the range of 1,000 to 100,000, particularly preferably in the range of 1,000 to 50,000 in terms of printing durability and image reproducibility.

  The photosensitive layer according to the present invention may contain a compound other than the water-soluble polymer compound as a binder, but the proportion of the water-soluble polymer compound in the binder is 80 to 100 with respect to the total binder. % By mass is preferable, and 90 to 100% is particularly preferable.

  The content of the binder is preferably 10% by mass to 95% by mass, and particularly preferably 30% by mass to 90% by mass with respect to the photosensitive layer.

  Examples of the binder that can be used in combination include polyvinyl butyral resin, polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, shellac, and other natural resins.

(High molecular compound having nonionic hydrophilic group)
The nonionic hydrophilic group of the polymer compound having a nonionic hydrophilic group is a group or bond that exhibits hydrophilicity without being ionized in water. For example, an alcoholic hydroxyl group, an aromatic hydroxyl group, an acid Examples include an amide group, a sulfonamide group, a thiol group, a pyrrolidone group, a polyoxyethylene group, a polyoxypropylene group, and a sugar residue.

  As the polymer compound having a nonionic hydrophilic group, a compound containing 30% by mass or more of the nonionic hydrophilic group is particularly preferable from the viewpoint of developability.

  The compound containing a nonionic hydrophilic group is preferably an oligomer or polymer having a mass average molecular weight of 1,000 to 50,000 in terms of developability and image reproducibility. Examples thereof include polymers obtained by polymerizing one or more unsaturated monomers having a functional group in the side chain, polyvinyl alcohol polymers, cellulose polymers that are polysaccharides, and glucose polymers.

  For example, as an unsaturated monomer having an amide group in the side chain, an amidation monomer of unsubstituted or substituted (meth) acrylamide, itaconic acid, fumaric acid, maleic acid or the like, N-vinylacetamide, N- Examples include vinylformamide and N-vinylpyrrolidone.

  More specific examples of unsubstituted or substituted (meth) acrylamide include (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N- Diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, diacetone (meth) acrylamide, methylol (meth) acrylamide, methoxymethyl (meth) acrylamide, butoxymethyl (meth) ) Acrylamide, propyl (meth) acrylamide, (meth) acryloylmorpholine, and the like.

  Further, in the case of an amidation monomer of a dibasic acid such as itaconic acid, a monoamide in which one carboxyl group is amidated, a diamide in which both carboxyl groups are amidated, and further one carboxyl group is amidated, An amide ester in which the other carboxyl group is esterified may be used.

  Examples of unsaturated monomers having a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and monomers obtained by adding ethylene oxide or propylene oxide to these (meth) acrylates. And methylol (meth) acrylamide, and methoxymethyl (meth) acrylamide and butoxymethyl (meth) acrylamide which are condensates of methylol (meth) acrylamide and methyl alcohol or butyl alcohol.

  The description such as “(meth) acryl”, “(meth) acrylate”, “(meth) acryloyl” means acryl or methacryl, acrylate or methacrylate, acryloyl or methacryloyl, respectively.

  The polyvinyl alcohol polymer will be described in more detail. A polymer obtained by completely or partially hydrolyzing a homopolymer or copolymer of a fatty acid vinyl monomer such as vinyl acetate or vinyl propionate, and a partial formalization or acetalization of this polymer. Examples include butyralized polymers.

  A compound containing 30% by mass or more of a nonionic hydrophilic group may have a crosslinkable functional group that reacts with a crosslinking agent. Specific examples of the crosslinkable functional group vary depending on the type of the crosslinking agent to be used, but nonionic ones are preferable, and examples thereof include a hydroxyl group, an isocyanate group, a glycidyl group, and an oxazoline group. In order to introduce these crosslinkable functional groups, unsaturated monomers having these functional groups, such as unsaturated monomers having a hydroxyl group described above, glycidyl (meth) acrylate, etc. as other unsaturated monomers having a glycidyl group ( What is necessary is just to copolymerize with a meth) acrylate monomer.

  In order to further improve the effect of the present invention, the compound containing 30% by mass or more of the nonionic hydrophilic group is other than the unsaturated monomer having the nonionic hydrophilic group and the unsaturated monomer having a crosslinkable functional group. In addition, other copolymerizable unsaturated monomers can be copolymerized.

  Examples of other copolymerizable unsaturated monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate, and methoxy (C1 to C50). ) Ethylene glycol (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, isopolonyl (meth) acrylate, adamantyl (meth) acrylate, cyclohexyl ( (Meth) acrylate, styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, and α-olefin (C4 to C30).

  Reaction described in “Crosslinking agent handbook” (Tosuke Kaneko, Junzo Yamashita, Taiseisha, 1981) as a crosslinking agent used to crosslink a compound containing 30% by mass or more of a nonionic hydrophilic group A combination of a crosslinking agent and a functional group can be selected.

  For example, known polyhydric alcohol compounds that react with a hydroxyl group, a glycidyl group, or an amide group as the crosslinkable functional group in a compound containing 30% by mass or more of a nonionic hydrophilic group as a crosslinking agent, Carboxylic acid compounds and their anhydrides, polyvalent glycidyl compounds (epoxy resins), polyvalent amine compounds, polyamide resins, polyvalent isocyanate compounds (including block isocyanates), oxazoline resins, amino resins And glyoxal.

  Among the crosslinking agents described above, various curing agents for epoxy resins such as various polyvalent glycidyl compounds (epoxy resins), oxazoline resins, amino resins, polyvalent amine compounds, and polyamide resins are known in terms of developability and printability. And glyoxal are preferred.

  Examples of amino resins include known melamine resins, urea resins, benzoguanamine resins, glycoluril resins, and modified resins of these resins, such as carboxy-modified melamine resins. In order to accelerate the crosslinking reaction, tertiary amines are used in combination with the above-described glycidyl compounds, and acidic compounds such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, and ammonium chloride are used in combination with amino resins. May be. When the photosensitive resin composition is heated with hot air, heated with a roller, heated with a laser, or the like, these crosslinking agents react to crosslink with a compound containing 30% by mass or more of a nonionic hydrophilic group.

In the present invention, among the water-soluble polymer compounds, polymer compounds having vinylpyrrolidone as a constituent monomer unit are particularly preferably used, and examples thereof include the following.
1. Vinylpyrrolidone-vinyl acetate copolymer (60/40) mass average molecular weight 34000
Product name: Lubiscol 64, manufactured by BASF Japan, VP / VA = 60 mol% / 40 mol% copolymer Vinylpyrrolidone-1 / butene copolymer (90/10) Mass average molecular weight 17000
Product Name: GANEX P-904 LC ISP chemicals
3. Vinylpyrrolidone-glycidyl methacrylate copolymer (70/30) mass average molecular weight 10,000
((C) Polymerizable, ethylenic double bond-containing compound)
The (A) polymerizable ethylenic double bond-containing compound of the present invention is a compound having an ethylenic double bond that can be polymerized by a photopolymerization initiator in a photosensitive layer that has been image-exposed.

In the present invention, it is preferable to use reaction products of the following compounds (C1) to (C3) as the polymerizable ethylenic double bond-containing compound.
(C1) a compound containing at least one ethylenic double bond and one hydroxyl group in the molecule (C2) a diisocyanate compound (C3) a diol compound having a tertiary amine structure in the molecule, or an intramolecular Compound having a secondary amine structure and one hydroxyl group each as C1 includes, for example, 2-hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, 2-hydroxypropyl methacrylate.

  C2 is a compound having two isocyanate groups. Examples of the (C2) diisocyanate compound include 1,3-bis (1-isocyanato-1-methylethyl) benzene (2 mol), 1,3-diisocyanate. Examples thereof include natobenzene, 1,3-diisocyanato-4-methylbenzene, and 1,3-di (isocyanatomethyl) benzene.

  Examples of C3 include Nn-butyldiethanolamine, N-methyldiethanolamine, 1,4-di (2-dihydroxyethyl), N-ethyldiethanolamine, and the like.

  As the reaction product, a compound represented by the following general formula (A) is particularly preferably used.

In general formula (A), R ¹ represents a hydrogen atom or a methyl group. X ¹ represents a divalent aliphatic group. X ² represents a divalent hydrocarbon group having an aromatic ring. X ³ represents a divalent substituent having a tertiary amine structure.

X ¹ is, for example, —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) —, —CH (CH ₃ ) CH ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ CH _2. CH ₂ -, but are mentioned _{-CH 2 CH 2 -, - CH} 2 CH (CH 3) -, - CH (CH 3) CH 2 - is preferred.

Examples of X ² include the following structures X2-1 to X2-10, and X2-3, X2-4, X2-7, X2-9, and X2-10 are preferable.

Examples of X ³ include the structures of X3-1 to X3-10, and X3-1, X3-2, X3-5, and X3-9 are preferable.

Examples of the compound represented by the general formula (A) include the following compounds.

  Polymerizable, ethylenic double bond-containing compounds include general radical polymerizable monomers, polyfunctional compounds having a plurality of addition-polymerizable ethylenic double bonds in the molecule generally used for UV curable resins. Monomers and polyfunctional oligomers can be used in combination.

  These compounds are not limited, but preferred examples include 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glycerol acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, Monofunctional acrylic acid esters such as tetrahydrofurfuryloxyhexanolide acrylate, acrylate of ε-caprolactone adduct of 1,3-dioxane alcohol, 1,3-dioxolane acrylate, or these acrylates as methacrylate, itaconate, crotonate, Methacrylic acid instead of maleate, itaconic acid, crotonic acid, maleic acid ester such as ethylene glycol Chryrate, triethylene glycol diacrylate, pentaerythritol diacrylate, hydroquinone diacrylate, resorcinol diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, diacrylate of hydroxypivalate neopentyl glycol, neo Diacrylate of pentyl glycol adipate, diacrylate of ε-caprolactone adduct of neopentyl glycol hydroxypivalate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1,3 -Ε-caprolactone of dioxane diacrylate, tricyclodecane dimethylol acrylate, tricyclodecane dimethylol acrylate Additives, bifunctional acrylates such as diglycidyl ether diacrylate of 1,6-hexanediol, or methacrylic acid, itaconic acid, crotonic acid, malein in which these acrylates are replaced with methacrylate, itaconate, crotonate, maleate Acid esters such as trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, Ε-caprolactone adduct of dipentaerythritol hexaacrylate, pyrogallol tria Relate, polyfunctional acrylic acid ester acid such as propionic acid / dipentaerythritol triacrylate, propionic acid / dipentaerythritol tetraacrylate, hydroxypivalylaldehyde-modified dimethylolpropane triacrylate, or these acrylates with methacrylate, itaconate, crotonate, Examples thereof include methacrylic acid, itaconic acid, crotonic acid, and maleic acid ester instead of maleate.

  Prepolymers can also be used as described above. Examples of the prepolymer include compounds as described below, and a prepolymer obtained by introducing acrylic acid or methacrylic acid into an oligomer having an appropriate molecular weight and imparting photopolymerizability can be preferably used. These prepolymers may be used singly or in combination of two or more, and may be used by mixing with the above-mentioned monomers and / or oligomers.

  Examples of prepolymers include adipic acid, trimellitic acid, maleic acid, phthalic acid, terephthalic acid, hymic acid, malonic acid, succinic acid, glutaric acid, itaconic acid, pyromellitic acid, fumaric acid, glutaric acid, pimelic acid, Polybasic acids such as sebacic acid, dodecanoic acid, tetrahydrophthalic acid, and ethylene glycol, propylene glycol, diethylene glycol, propylene oxide, 1,4-butanediol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, trimethylol Polyester obtained by introducing (meth) acrylic acid into a polyester obtained by combining polyhydric alcohols such as propane, pentaerythritol, sorbitol, 1,6-hexanediol, 1,2,6-hexanetriol Chlorates such as bisphenol A, epichlorohydrin, (meth) acrylic acid, and epoxy acrylates in which (meth) acrylic acid is introduced into an epoxy resin such as phenol novolac, epichlorohydrin, (meth) acrylic acid, such as ethylene glycol, adipine Acid / tolylene diisocyanate / 2-hydroxyethyl acrylate, polyethylene glycol / tolylene diisocyanate / 2-hydroxyethyl acrylate, hydroxyethylphthalyl methacrylate / xylene diisocyanate, 1,2-polybutadiene glycol / tolylene diisocyanate / 2-hydroxyethyl acrylate , Trimethylolpropane, propylene glycol, tolylene diisocyanate, 2-hydroxyethyl acrylate In addition, urethane acrylates in which (meth) acrylic acid is introduced into urethane resin, for example, silicone resin acrylates such as polysiloxane acrylate, polysiloxane diisocyanate, 2-hydroxyethyl acrylate, etc., and (meth) acryloyl in oil-modified alkyd resins Examples thereof include prepolymers such as alkyd-modified acrylates having introduced groups and spirane resin acrylates.

  The photosensitive layer according to the present invention includes a phosphazene monomer, triethylene glycol, isocyanuric acid EO (ethylene oxide) modified diacrylate, isocyanuric acid EO modified triacrylate, dimethylol tricyclodecane diacrylate, trimethylolpropane benzoic acid benzoic acid. Addition-polymerizable oligomers and prepolymers having monomers such as esters, alkylene glycol type acrylic acid-modified, urethane-modified acrylates, and structural units formed from the monomers can be contained.

  Furthermore, examples of the ethylenic monomer that can be used in combination with the present invention include phosphate ester compounds containing at least one (meth) acryloyl group. The compound is not particularly limited as long as it is a compound in which at least part of the hydroxyl group of phosphoric acid is esterified and has a (meth) acryloyl group.

  In addition, JP-A-58-212994, 61-6649, 62-46688, 62-48589, 62-173295, 62-187092, 63- 67189, JP-A-1-244891, and the like. Further, “11290 Chemical Products”, Chemical Industry Daily, p. 286-p. 294, “UV / EB Curing Handbook (raw material)”, Kobunshi Publishing Co., p. The compounds described in 11 to 65 can also be suitably used in the present invention. Of these, compounds having two or more acrylic groups or methacryl groups in the molecule are preferred in the present invention, and those having a molecular weight of 10,000 or less, more preferably 5,000 or less are preferred.

  In addition, acrylates or alkyl acrylates described in JP-A-1-105238 and JP-A-2-127404 can be used.

  The content of the polymerizable (B) polymerizable ethylenic double bond-containing compound according to the present invention in the photosensitive layer is preferably 0.5% by mass to 15.0% by mass with respect to the photosensitive layer. 0-8.0 mass% is preferable.

(Sensitizing dye)
The photosensitive layer according to the present invention contains a sensitizer. Examples of the sensitizer include cyanine, merocyanine, porphyrin, spiro compound, ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, phenothiazine, acridine, acridone, azo compound, diphenylmethane, triphenylmethane, triphenylamine, and coumarin derivatives. Quinacridone, indigo, styryl, pyrylium compound, pyromethene compound, pyrazolotriazole compound, benzothiazole compound, barbituric acid derivative, thiobarbituric acid derivative, ketoalcohol borate complex, and the like.

  Examples of the coumarin derivatives include B-1 to B-22 coumarin derivatives of JP-A-8-129258, D-1 to D-32 coumarin derivatives of JP-A 2003-21901, and JP-A 2002. No. 1-363206, 1 to 21 coumarin derivatives, JP 2002-363207 A to 40 coumarin derivatives, JP 2002-363208 A to 34 coumarin derivatives, JP 2002-363209 A, Examples thereof include 1 to 56 coumarin derivatives and can be preferably used.

  Examples of other sensitizing dyes that can be preferably used include, for example, JP-A No. 2000-98605, JP-A No. 2000-147663, JP-A No. 2000-206690, JP-A No. 2000-258910, and JP-A No. 2000-309724. And spectral sensitizers described in JP-A No. 2001-042524, JP-A No. 2002-202598, and JP-A No. 2000-221790.

  In the present invention, a sensitizing dye having an absorption maximum wavelength of 370 to 420 nm is preferably used.

(Mercapto compound)
The photosensitive layer according to the present invention preferably contains a mercapto compound from the viewpoint of sensitivity and sensitivity fluctuation prevention.

  The mercapto compound is a compound having a mercapto group. For example, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercapto-4-methyl-5-acetylthiazole, 2-mercapto-4 -Methylthiazole, 1-methyl-2-mercaptoimidazole, 2-mercapto-4,5-dimethylthiazole, 2-mercapto-5-acetylthiazole, 1-methyl-2-mercaptobenzimidazole, 1-methyl-2-mercapto Examples include -4-methyl-5-acetylimidazole, 2-mercaptooxazole, 2-mercaptobenzoxazole, and 2-mercapto-2-imidazoline.

  The content of the mercapto compound is preferably from 0.01 to 5% by weight, particularly preferably from 0.1 to 1% by weight, based on the photosensitive layer.

(Various additives)
In the photosensitive layer according to the present invention, in addition to the above-described components, in order to prevent unnecessary polymerization of the ethylenic double bond monomer that can be polymerized during the production or storage of the photosensitive lithographic printing plate material, It is desirable to add a polymerization inhibitor.

  Suitable polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol) 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine cerium salt, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5) -Methylbenzyl) -4-methylphenyl acrylate and the like.

  The addition amount of the polymerization inhibitor is preferably about 0.01% to about 5% with respect to the mass of the total solid content of the photosensitive layer. If necessary, higher fatty acid derivatives such as behenic acid and behenic acid amide may be added to prevent polymerization inhibition due to oxygen, or it may be unevenly distributed on the surface of the photosensitive layer during the drying process after coating. Good. The amount of the higher fatty acid derivative added is preferably about 0.5% to about 10% of the total composition.

  Moreover, a coloring agent can also be used and a conventionally well-known thing can be used conveniently as a coloring agent including a commercially available thing. Examples include those described in the revised new edition “Pigment Handbook”, edited by Japan Pigment Technology Association (Seikodo Shinkosha), Color Index Handbook, and the like.

  Examples of the pigment include black pigment, yellow pigment, red pigment, brown pigment, purple pigment, blue pigment, green pigment, fluorescent pigment, and metal powder pigment. Specifically, inorganic pigments (titanium dioxide, carbon black, graphite, zinc oxide, Prussian blue, cadmium sulfide, iron oxide, and lead, zinc, barium and calcium chromates) and organic pigments (azo-based, thioindigo) , Anthraquinone, anthanthrone, and triphendioxazine pigments, vat dye pigments, phthalocyanine pigments and derivatives thereof, quinacridone pigments, and the like.

  Among these, it is preferable to select and use a pigment having substantially no absorption in the absorption wavelength region of the spectral sensitizing dye corresponding to the exposure laser to be used. In this case, an integrating sphere at the laser wavelength to be used is used. It is preferable that the reflection absorption of the used pigment is 0.05 or less. Moreover, as an addition amount of a pigment, 0.1-10 mass% is preferable with respect to solid content of the said composition, More preferably, it is 0.2-5 mass%.

  From the viewpoints of pigment absorption in the above-mentioned photosensitive wavelength region and visible image properties after development, violet pigments and blue pigments are preferably used. Such as, for example, cobalt blue, cerulean blue, alkali blue lake, phonatone blue 6G, Victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue first sky blue, indanthrene blue, indico, dioxane violet, iso Violanthrone Violet, Indanthrone Blue, Indanthrone BC and the like can be mentioned. Among these, phthalocyanine blue and dioxane violet are more preferable.

  In addition, the photosensitive layer can contain a surfactant as a coating property improving agent as long as the performance of the present invention is not impaired. Of these, fluorine-based surfactants are preferred.

  In order to improve the physical properties of the cured film, additives such as an inorganic filler, a plasticizer such as dioctyl phthalate, dimethyl phthalate, and tricresyl phosphate may be added. These addition amounts are preferably 10% or less of the total solid content.

  The photosensitive layer according to the present invention can be provided by applying and drying a photosensitive layer coating solution containing the components contained in the photosensitive layer on a support. Solvents used in preparing the photosensitive layer coating solution include, for example, alcohol: polyhydric alcohol derivatives such as sec-butanol, isobutanol, n-hexanol, benzyl alcohol, diethylene glycol, triethylene glycol, and tetraethylene glycol. 1,5-pentanediol, ethers: propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ketones, aldehydes: diacetone alcohol, cyclohexanone, methylcyclohexanone, esters: lactic acid Preferred examples include ethyl, butyl lactate, diethyl oxalate, and methyl benzoate.

The amount attached on the support of the photosensitive layer according to the present invention, be 0.1g / m ² ~10g / m ² are preferred especially ^{0.5g / m 2 ~5g / m 2} , sensitivity, preservability From the viewpoint of

(Protective layer)
The photosensitive layer according to the present invention has a protective layer containing polyvinyl alcohol thereon (on the side opposite to the support).

  This protective layer has an oxygen blocking function and contains polyvinyl alcohol.

  As the polyvinyl alcohol, those having a saponification degree of 80 mol% or more can be preferably used.

  Among these, those having a saponification degree of 90 mol% or more can be preferably used.

  The content of polyvinyl alcohol in the protective layer is preferably 50% by mass to 100% by mass, and particularly preferably 70% by mass to 95% by mass.

  It is preferable that polyvinyl pyrrolidone coexists in the protective layer.

  In addition to the above two polymers, polysaccharides, polyethylene glycol, gelatin, glue, casein, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, hydroxyethyl starch, gum arabic, sucrose octaacetate, ammonium alginate, sodium alginate, polyvinylamine Water-soluble polymers such as polyethylene oxide, polystyrene sulfonic acid, polyacrylic acid, and water-soluble polyamide can also be used in combination.

  In the protective layer according to the present invention, the peeling force between the photosensitive layer and the protective layer is preferably 35 mN / mm or more, more preferably 50 mN / mm or more, and further preferably 75 mN / mm or more. Preferred examples of the protective layer composition include those described in Japanese Patent Application No. 8-161645.

  Peeling force is measured by applying a predetermined width of adhesive tape with a sufficiently large adhesive force on the protective layer and peeling it with the protective layer at an angle of 90 degrees with respect to the plane of the photosensitive lithographic printing plate material. Can be obtained.

  The protective layer can further contain a surfactant, a matting agent and the like as required. The protective layer composition is dissolved in a suitable solvent, applied onto the photosensitive layer and dried to form a protective layer. The main component of the coating solvent is particularly preferably water or alcohols such as methanol, ethanol, i-propanol.

  The thickness of the protective layer is preferably from 0.1 to 5.0 μm, particularly preferably from 0.5 to 3.0 μm.

(Support)
The support according to the present invention is a plate or film capable of carrying a photosensitive layer, and preferably has a hydrophilic surface on the side where the photosensitive layer is provided.

  Examples of the support according to the present invention include a metal plate such as aluminum, stainless steel, chromium and nickel, or a laminate obtained by laminating or vapor-depositing the above metal thin film on a plastic film such as a polyester film, a polyethylene film and a polypropylene film. .

  Moreover, although what hydrophilized the surface, such as a polyester film, a vinyl chloride film, a nylon film, etc. can be used, an aluminum support body is used preferably.

  In the case of an aluminum support, pure aluminum or an aluminum alloy is used.

  Various aluminum alloys can be used as the support, and for example, alloys of metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum are used. . Further, the aluminum support having a roughened surface is used for water retention.

  In the case of using an aluminum support, it is preferable to perform a degreasing treatment in order to remove the rolling oil on the surface prior to roughening (graining treatment). As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is generated on the surface of the support. In this case, the substrate is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof and desmutted. It is preferable to perform the treatment. Examples of the roughening method include a mechanical method and a method of etching by electrolysis.

  The mechanical roughening method used is not particularly limited, but a brush polishing method and a honing polishing method are preferable.

  The electrochemical surface roughening method is not particularly limited, but a method of electrochemical surface roughening in an acidic electrolyte is preferable.

  As the electrochemical surface roughening treatment, an AC electrolytic surface roughening treatment in an electrolytic solution containing hydrochloric acid is preferably used.

  The arithmetic average roughness (Ra) of the roughened surface is preferably 0.2 μm or more and 0.8 μm or less.

  That is, as a support, dyeing is formed by a process including electrochemical treatment in an aqueous solution containing hydrochloric acid, and the arithmetic average roughness (Ra) of this rough surface is 0.2 μm or more, A support having a size of 0.8 μm or less is particularly preferred.

  The arithmetic average roughness (Ra) in the present invention is defined by ISO4287.

  That is, the arithmetic average roughness (Ra) is obtained by extracting a portion of the measured length lr from the roughness curve in the direction of the center line, and setting the X axis in the direction of the extracted portion and the Y axis in the direction of the vertical magnification y = Z. When expressed by (x), the value obtained by the following formula is expressed in micrometers (μm).

  The value of Ra can be measured using, for example, a commercially available contact roughness meter such as SE1700α (manufactured by Kosaka Laboratory Ltd.).

  The concentration of hydrochloric acid in the AC electrolytic surface roughening treatment in an electrolytic solution containing hydrochloric acid is preferably 0.03 to 3% by mass.

  After the surface is roughened by the electrochemical surface roughening method, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum scraps on the surface. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution.

The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  The mechanical surface roughening method and the electrochemical surface roughening method may each be used alone for roughing, or the mechanical surface roughening method followed by the electrochemical surface roughening method. You may roughen.

  Following the roughening treatment, an anodic oxidation treatment can be performed. There is no restriction | limiting in particular in the method of the anodizing process which can be used in this invention, A well-known method can be used. By performing the anodizing treatment, an oxide film is formed on the support.

  The anodized support may be sealed as necessary. These sealing treatments can be performed using known methods such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.

  Furthermore, after performing these treatments, water-soluble resins such as polyvinylphosphonic acid, polymers and copolymers having sulfonic acid groups in the side chain, polyacrylic acid, water-soluble metal salts (for example, zinc borate) or Also suitable are those coated with a yellow dye, amine salt or the like. Further, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A No. 5-304358 is covalently used.

(Application)
The above photosensitive layer coating solution can be coated on a support by a conventionally known method and dried to prepare a photosensitive lithographic printing plate material.

  Examples of coating methods for the coating liquid include air doctor coater method, blade coater method, wire bar method, knife coater method, dip coater method, reverse roll coater method, gravure coater method, cast coating method, curtain coater method and extrusion coater method. I can list them.

  The drying temperature of the photosensitive layer is preferably in the range of 60 to 160 ° C., more preferably 80 to 140 ° C., and particularly preferably 90 to 120 ° C.

(Preparation method of lithographic printing plate)
In the lithographic printing plate preparation method of the present invention, the above-described photosensitive lithographic printing plate material for water development is subjected to image exposure, heat treatment, and development treatment with water in this order.

(Image exposure)
As a light source used for image exposure according to the present invention, it is preferable to use laser light having an emission wavelength of 370 to 420 nm.

As a light source for exposing the photosensitive lithographic printing plate of the present invention, for example, a He—Cd laser (441 nm), a combination of Cr: LiSAF and SHG crystal (430 nm) as a solid laser, KNbO ₃ as a semiconductor laser system, a ring A resonator (430 nm), AlGaInN (350 nm to 450 nm), an AlGaInN semiconductor laser (commercially available InGaN semiconductor laser 400 to 410 nm) and the like can be mentioned.

  Laser exposure is suitable for direct writing without using a mask material because light exposure can be performed in the form of a beam according to image data.

  When a laser is used as a light source, it is easy to reduce the exposure area to a very small size, and high-resolution image formation is possible.

  Laser scanning methods include cylindrical outer surface scanning, cylindrical inner surface scanning, and planar scanning. In the cylindrical outer surface scanning, laser exposure is performed while rotating a drum around which the recording material is wound, and the rotation of the drum is the main scanning and the movement of the laser light is the sub scanning. In cylindrical inner surface scanning, a recording material is fixed to the inner surface of the drum, a laser beam is irradiated from the inside, and a main scanning is performed in the circumferential direction by rotating a part or all of the optical system. Sub scanning is performed in the axial direction by linearly moving all of them in parallel with the drum axis. In plane scanning, a laser beam main scan is performed by combining a polygon mirror, a galvanometer mirror, and an fθ lens, and a sub-scan is performed by moving a recording medium. Cylindrical outer surface scanning and cylindrical inner surface scanning are easier to increase the accuracy of the optical system and are suitable for high-density recording.

In the present invention, image exposure is preferably performed with a plate surface energy (energy on the plate material) of 10 mJ / cm ² or more, and the upper limit is 500 mJ / cm ² . More preferably, it is 10-300 mJ / cm < ² >. For this energy measurement, for example, a laser power meter PDGDO-3W manufactured by OphirOptics can be used.

(Heat treatment)
The heat treatment according to the present invention is a treatment for heating the plate material after exposure and before development, and is performed to promote radical polymerization initiated imagewise by the above-described image exposure. As a heat treatment method, a method of putting in a temperature-controllable treatment tank such as a circulating thermostat for a certain period of time, conveyance equipment such as a belt conveyor and a conveyance roller, and a heating unit such as an infrared heater and a hot air heater There is a method of overheating while conveying the plate.

  Specifically, a heating device equipped with a transport facility such as a Wisconsin oven can be used for the method of overheating while transporting the plate, and a heating facility is provided at the plate insertion port of an automatic processor used for development processing. Things can be used. As such an automatic developing apparatus, a commercially available automatic developing machine for a photopolymer CTP plate can be used.

  As heating conditions, it is preferable to perform heating for 5 seconds to 2 minutes under the condition that the temperature of the plate reaches 80 to 160 degrees in the final stage of the heat treatment. More preferably, heating is performed for 7 seconds to 1 minute under the condition that the temperature reaches 85 to 130 degrees.

  The temperature of the plate at the final stage of the heat treatment can be confirmed by the temperature displayed on the thermo label after a commercially available thermo label or the like is attached to the back of the plate and the heat treatment is performed.

(Development with water)
The development with water according to the present invention is a means for removing the non-image area by washing the plate with well water, tap water, etc., and an additive such as a surfactant or a water-soluble resin is added to the water for development. The method which does not add substantially is pointed out. Here, “substantially not add” means that no additive exceeding 1% by mass is added. Further, the components in the non-image area of the plate material are eluted in the developing water by the development process, but these components are not regarded as additives.

  As a means for stably and efficiently developing with water, it is preferable to use a commercially available automatic developing machine for a photopolymer CTP plate, and usually use water in a developing tank containing an alkaline developer.

(Plate protectant)
The plate surface protective agent according to the present invention contains a water-soluble resin and a surfactant.

  In the lithographic printing plate preparation method of the present invention, it is preferable that the printing plate material is subjected to image exposure, heat treatment, and development treatment with water, and then treated with a plate surface protective agent.

  Examples of water-soluble resins include gum arabic, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, polyacrylamide and copolymers thereof, vinyl methyl ether / Examples thereof include a maleic anhydride copolymer, a vinyl acetate / maleic anhydride copolymer, and a styrene / maleic anhydride copolymer. The content of these water-soluble resins is suitably 0.1 to 50% by mass, more preferably 0.5 to 3.0% by mass in the composition.

  In addition, examples of the surfactant according to the present invention include an anionic surfactant and a nonionic surfactant. For example, anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfones. Acid salts, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, polyoxyethylene aryl ether sulfonates, polyoxyethylene naphthyl ether sulfonates, N-methyl-N-oleyl taurine sodium salts N-alkylsulfosuccinic acid monoamido disodium salts, petroleum sulfonates, nitrated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, Rualkyl nitrates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ethers Phosphate ester salts, polyoxyethylene alkylphenyl ether phosphate ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalenesulfonate formalin condensates Etc. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, and alkyl naphthalene sulfonates are particularly preferably used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene aryl ethers, polyoxyethylene naphthyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxy Propylene alkyl ether, glycerin fatty acid partial ester, sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol mono fatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid moiety Esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylenated ester List oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, etc. It is done. Of these, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used. Fluorine-based and silicon-based anions and nonionic surfactants can also be used.

  Examples of preferable surfactants include surfactants added to the lithographic printing plate surface protective agents described in JP-A Nos. 2004-167903, 2004-230650, and 2005-43393. .

  Two or more of these surfactants can be used in combination. For example, two or more different from each other can be used in combination. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable. Although the usage-amount of the said surfactant does not need to specifically limit, Preferably it is 0.01-20 mass% of a post-processing liquid.

  The pH of the plate surface protective agent according to the present invention is preferably from 3.0 to 9.0.

  When using in the acidic range pH 3-6, it adjusts by adding a mineral acid, an organic acid, an inorganic salt, etc. in aqueous solution. The addition amount is preferably 0.01 to 2% by mass. Examples of mineral acids include nitric acid, sulfuric acid, phosphoric acid, and metaphosphoric acid.

  Examples of the organic acid include citric acid, acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, tartaric acid, malic acid, lactic acid, levulinic acid, phytic acid, and organic phosphonic acid.

  Further, examples of the inorganic salt include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, nickel sulfate, sodium hexamethanoate, sodium tripolyphosphate, and the like. You may use together at least 1 sort (s) or 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

  When used in the basic region pH 8 to 9, a water-soluble organic base or inorganic base can be added to adjust the pH. A water-soluble organic base is preferred, and examples include triethanolamine, diethanolamine, and ethanolamine.

  Moreover, antiseptic | preservative, an antifoamer, etc. can be added to a plate surface protective agent.

  For example, as a preservative, phenol or a derivative thereof, o-phenylphenol, p-chlorometacresol, hydroxybenzoic acid alkyl ester, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benzoisothiazoline-3- ON, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, derivatives of pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives and the like. A preferable addition amount is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the type of bacteria, molds, yeasts, but 0.01% with respect to the plate surface protective agent at the time of use. The range of ˜4% by mass is preferable, and it is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization. As the antifoaming agent, a silicon antifoaming agent is preferable. Among them, emulsification dispersion type and solubilization can be used. Preferably the range of 0.01-1.0 mass% is optimal.

  A chelate compound may be further added to the plate surface protective agent. Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, sodium salt thereof; ethylenediamine disuccinic acid, potassium salt thereof. Triethylenetetramine hexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid, potassium salt thereof, sodium salt thereof: nitrilotriacetic acid, sodium salt thereof; 1-hydroxyethane-1,1-diphosphone Acids, potassium salts, sodium salts; organic phosphonic acids or phosphonoalkanetricarboxylic acids such as aminotri (methylenephosphonic acid), potassium salts, sodium salts, etc. It can be mentioned.

  An organic amine salt is also effective in place of the sodium salt and potassium salt of the chelating agent. These chelating agents are selected so that they are stably present in the gum solution composition and do not impair the printability. The addition amount is suitably 0.001 to 1.0% by mass.

  In addition to the above components, a sensitizer can be added as necessary. For example, hydrocarbons such as turpentine oil, xylene, toluene, low heptane, solvent naphtha, kerosene, mineral spirit, petroleum fraction having a boiling point of about 120 ° C to about 250 ° C, such as dibutyl phthalate, dihebutyl phthalate, di-n-octyl Phthalic acid diester agents such as phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, such as dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di ( 2-ethylhexyl) aliphatic dibasic acid esters such as sebacate and dioctyl sebacate, epoxidized triglycerides such as epoxidized soybean oil, such as tricresyl phosphate, trioctylfolate Feto, phosphoric acid esters such as tris chloroethyl phosphate, for example, freezing point, such as benzoic acid esters of benzyl benzoate and at 15 ℃ below boiling point at one atmosphere include 300 ° C. or more plasticizers.

  Furthermore, caproic acid, enanthic acid, caprylic acid, helargonic acid, capric acid, undecyl acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoserine Saturated fatty acids such as acid, serotic acid, heptacosanoic acid, montanic acid, melicinic acid, lactelic acid, isovaleric acid, and acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, celetic acid, nillic acid, buteticidin Examples also include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, sardine acid, talylic acid and licanoic acid. More preferably, it is a fatty acid that is liquid at 50 ° C., more preferably 5 to 25 carbon atoms, and most preferably 8 to 21 carbon atoms. These sensitizers can be used alone or in combination of two or more. A preferable range for the amount used is 0.01 to 10% by mass, and a more preferable range is 0.05 to 5% by mass.

  The treatment with the plate surface protective agent is a method of removing excess plate surface protective agent with a roller after dipping into a treatment tank containing the plate surface protective agent, after supplying the plate surface protective agent to the plate surface by spraying, showering, etc. Examples thereof include a method of removing excess plate surface protective agent with a roller and the like, and a method of applying on a lithographic printing plate with a sponge infiltrated with a plate surface protective agent.

  A preferred embodiment of the processing with the plate surface protective agent is that the plate surface protective solution is put into a finisher processing section of an automatic processor for a photopolymer CTP plate which is generally commercially available, and processed continuously with the heating step and the developing step described above. The method of performing is preferable.

(printing)
The lithographic printing plate material of the present invention is subjected to printing after image exposure. As a printing machine, a general lithographic offset printing machine using fountain solution as described above can be used. Printing paper, printing ink, fountain solution, etc. used for printing are not particularly limited.

  In recent years, in the printing industry, from the viewpoint of environmental protection, inks that do not use petroleum-based volatile organic compounds (VOC) have been developed and are widely used as printing inks. It is particularly large when using the printing ink.

  These inks are preferably inks containing soybean oil.

  The ink containing soybean oil is usually a mixture of organic / inorganic pigments, binder resin, soybean oil, high boiling petroleum solvent, and other additives such as plasticizers, stabilizers, drying agents, thickeners, It may contain a dispersant, a filler, and the like.

  Inks that are preferably used for printing of the present invention include inks certified by the American Soybean Association (ASA) with a soy seal certification system.

  As soybean oil, known soybean oil can be used, and edible soybean oil (refined soybean oil) certified by Japanese Agricultural Standards is particularly preferably used.

  The preferred amount of soybean oil to be added varies depending on the type of ink, but is 20 to 50% by mass for sheet-fed ink and foam ink, 7 to 20% by mass for off-ring heat set ink, and 40 to 50 mass for black ink for newspaper ink. %, 30 to 40% by mass for color ink, and 20 to 30% by mass for business foam ink.

  As organic / inorganic pigments, disazo yellow, brilliant carmine 6B, phthalocyanine blue, lake red C, carbon black, titanium oxide, calcium carbonate and the like can be used.

  As binder resin, natural or processed resin such as rosin, copal, dammar, shellac, cured rosin, rosin ester, phenol resin, rosin modified phenol resin, 100% phenol resin, maleic acid resin, alkyd resin, petroleum resin, vinyl resin Acrylic resin, polyamide resin, epoxy resin, amino alkyd resin, polyurethane resin, amino blast resin and the like are preferable.

  Inks containing soybean oil are sold by ink manufacturers and can be easily obtained. For example, Naturalis 100 (Naturalith) sheet-fed ink, WebWorld Advan off-wheel ink, <above, Dainippon Ink Chemical Industry Co., Ltd.>, TK High Unity SOY Sheetfed Ink, TK High Echo SOY Sheetfed Ink, CK Win Echo SOY Sheetfed Ink, WD Super Leo Echo SOY Off Wheel Ink, WD Leo Echo SOY Off Wheel Ink, SCRSOY Business Form inki <above, Toyo Ink Co., Ltd.>, Soyselvo sheet-fed ink <Tokyo Ink Co., Ltd.> and the like.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the examples, “parts” represents “parts by mass” unless otherwise specified.
Example 1
[Production of support]
Using a JIS A 1050 aluminum plate having a thickness of 0.30 mm and a width of 1030 mm, the treatment was continuously performed as follows.

(A) The aluminum plate was etched by spraying at a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. to dissolve the aluminum plate by 0.3 g / m ² . Thereafter, washing with water was performed by spraying.

  (B) A desmut treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (including 0.5% by mass of aluminum ions), and then washed with water by spraying.

(C) An electrochemical surface roughening treatment was continuously performed using an alternating voltage of 60 Hz. The electrolytic solution at this time contains 1.1% by mass of hydrochloric acid, 0.5% by mass of aluminum ions, and 0.5% by mass of acetic acid. The temperature was 21 ° C. The AC power source was subjected to electrochemical surface roughening treatment using a sine wave alternating current having a time TP of 2 msec until the current value reached a peak from zero, using a carbon electrode as a counter electrode. The current density was an effective value of 50 A / dm ² and the energization amount was 900 C / dm ² . Then, water washing by spraying was performed.

  (D) A desmut treatment was performed for 10 seconds with a phosphoric acid concentration 20 mass% aqueous solution (containing 0.5 mass% of aluminum ions) at a temperature of 60 ° C., followed by water washing by spraying.

  (E) An anodizing apparatus of an existing two-stage feed electrolytic treatment method (first and second electrolysis unit length 6 m, first feed unit length 3 m, second feed unit length 3 m, first and second feed electrode lengths 2.4 m each ) Was used to perform anodization at a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions) at a temperature of 38 ° C. Thereafter, washing with water was performed.

  At this time, in the anodizing device, the current from the power source flows to the first power supply electrode provided in the first power supply unit, flows to the plate-like aluminum via the electrolytic solution, An oxide film is formed on the surface, passes through the electrolytic electrode provided in the first power feeding portion, and returns to the power source.

On the other hand, the current from the power source flows to the second power feeding electrode provided in the second power feeding portion, similarly flows to the plate-like aluminum via the electrolytic solution, and an oxide film is formed on the surface of the plate-like aluminum by the second electrolysis portion. Although the amount of electricity fed from the power source to the first feeding unit and the amount of electricity fed from the power source to the second feeding unit are the same, the feeding current density on the oxide film surface in the second feeding unit is about It was 25 A / dm ² . In the second power feeding unit, power is fed from the oxide film surface of 1.35 g / m ² . The final oxide film amount was 2.7 g / m ² . Furthermore, after spray water washing, it was immersed in 0.4 mass% polyvinylphosphonic acid solution for 30 seconds, and was hydrophilized. The temperature was 85 ° C. Thereafter, it was washed with spray water and dried with an infrared heater.

  At this time, the center line average roughness (Ra) of the surface was 0.65 μm.

(Preparation of photosensitive lithographic printing plate material)
On the support, a photopolymerizable photosensitive layer coating solution 1 having the following composition was applied with a wire bar so as to have a dry weight of 1.5 g / m ² , and dried at 95 ° C. for 1.5 minutes. A sample was obtained.

Further, on the photopolymerized photosensitive layer coating sample, an oxygen barrier layer coating solution having the following composition was coated with a wire bar so that the drying rate became 2.0 g / m ² and dried at 65 ° C. for 3 minutes. A photosensitive lithographic printing plate material sample having an oxygen blocking layer was prepared.

(Photopolymerizable photosensitive layer coating solution 1)
Compound containing ethylenic double bond (NK Oligo U-4HA: Shin-Nakamura Chemical Co., Ltd.)
5.0 parts ethylenic double bond-containing compound (NK ester 3G: Shin-Nakamura Chemical Co., Ltd.)
25.0 parts Ethylenic double bond-containing compound (Denacol Acrylate DA314: Nagase ChemteX Corporation) 25.0 parts N-carboxymethylacridone 4.0 parts 2,2′-bis (2-chlorophenyl)- 4,4 ′, 5,5′-tetraphenylbisimidazole 3.0 parts 2-mercaptobenzothiazole 0.3 part Poly (vinyl pyrrolidone / vinyl acetate copolymer) VA64 (manufactured by BASF)
20.0 parts Polyvinylpyrrolidone Rubytec K30 (manufactured by BASF) 20.0 parts Acetylene surfactant (Surfinol 465; manufactured by Air Products) 0.5 part Phthalocyanine pigment dispersion MHI # 454 (manufactured by Gokoku Dye) 0 parts Preservative 1 1.0 part Water 450 parts Ethanol 450 parts (Oxygen barrier coating liquid)
Polyvinyl alcohol (GL-05: manufactured by Nippon Synthetic Chemical Co., Ltd.) 74 parts Polyvinylpyrrolidone (PVP K-30: manufactured by APS Japan) 10 parts Polyethyleneimine (Lupazole WF: manufactured by BASF) 5 parts Surfactant (Surfinol) 465: manufactured by Nissin Chemical Industry Co., Ltd.) 0.5 part water 900 part (preservative 1 composition)
5-chloro-2-methyl-4-isothiazolin-3-one 1.2 parts 2-methyl-4-isothiazolin-3-one 0.4 parts magnesium chloride 1.0 part magnesium nitrate 22.4 parts water 75 parts above Using a plate setter News (manufactured by ECRM) equipped with a light source of 405 nm in an environment of yellow safety light, the photosensitive lithographic printing plate material prepared by the method of 1,200 dpi (dpi is 2.54 cm per 2.54 cm) The image exposure was performed with an exposure setting value (exposure value) of 200 with a line number of 100 LPI.

  After the exposure, the film was developed using an automatic developing machine raptor polymer (manufactured by Grunz & Jensen) for photopolymer plates in an environment of yellow safety light. As processing conditions, the conveyance speed is 60 cm / min, the preheat temperature is set to 110 ° C. when measured with the thermolabel attached to the back side of the plate at the conveyance speed, the pre-washing is running water, and the developing tank is a tap water. Water was added to adjust the temperature to 28 ° C., the rinsing tank was made to be running water, and a finisher solution having the following composition was placed in the finisher layer.

(Finisher composition)
Water 100 parts Benzyl alcohol 1 part Ethylene glycol 1 part Polyoxyethylene naphthyl ether (oxyethylene average number n = 13) 1 part Dioctyl sulfosuccinate sodium salt 0.5 part Arabic gum 2 parts Monobasic ammonium phosphate 0.05 Part Citric acid 0.05 part Ethylenediaminetetraacetate tetrasodium salt 0.05 part The prepared lithographic printing plate was coated with a printing machine (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.) and printed ink (Toyo Ink Co., Ltd.) When printing was performed using Toyo King Hi-Echo M Red) and dampening water (Tokyo Liquid, Inc. H liquid SG-51 concentration 1.5%), a good printed product could be obtained.

In addition, the photosensitive lithographic printing plate produced under the same conditions was subjected to a running treatment experiment for a total of 5 days with a treatment of 20 m ² in terms of area per day under the above conditions. During this time, the water in the developing tank was only replenished with the reduced amount due to evaporation and removal, and the processing solution in the automatic developing machine was left as it was for 5 days. The water in the developing tank was kept in a good state with no syrup or odor.
(Example 2)
In Example 1, the preservative 1 was removed from the photopolymerizable photosensitive layer coating solution 1, and 1 part of the preservative 1 was added to the oxygen barrier layer coating solution instead. As a result, the produced lithographic printing plate showed the same printability as in Example 1, and the water in the developing tank was in a good state with no elutriation or off-flavor even after 5 days of running test. Was kept.
(Example 3)
In Example 1, 1 part of the preservative 1 was also added to the oxygen barrier layer coating solution, and the others were carried out in the same manner. As a result, the produced lithographic printing plate showed printability similar to that in Example 1, and running. After the processing experiment, even after 10 days of standing, the water in the developing tank was kept in a good state without the occurrence of chickenpox and off-flavor.
(Comparative Example 1)
In Example 1, the preservative 1 was removed from the photopolymerizable photosensitive layer coating solution 1 and the others were carried out in the same manner. As a result, the produced lithographic printing plate showed the same printability as in Example 1, but the running treatment experiment Thereafter, after standing for 5 days, the occurrence of chickenpox was observed in the water in the developing tank, and at the same time a rotten odor was observed.

Claims (7)

On the support, (A) a photopolymerization initiator, (B) a binder, (C) a polymerizable ethylenic double bond-containing compound and (D) a sensitizing dye-containing photosensitive layer, In the photosensitive lithographic printing plate material for water development having a protective layer containing polyvinyl alcohol on the photosensitive layer, the photosensitive layer contains a water-soluble polymer as the binder (B), and the photosensitive layer and the photosensitive layer A photosensitive lithographic printing plate material for water development, wherein at least one of the protective layers contains a preservative. The photosensitive lithographic printing plate material for water development according to claim 1, wherein the preservative is an isothiazoline derivative. The (C) polymerizable ethylenic double bond-containing compound is a reaction product of the following compounds (C1), (C2) and (C3): Photosensitive lithographic printing plate material for water development.
(C1) a compound containing at least one ethylenic double bond and one hydroxyl group in the molecule (C2) a diisocyanate compound (C3) a diol compound having a tertiary amine structure in the molecule, or an intramolecular Having a secondary amine structure and one hydroxyl group The water-soluble photosensitive lithographic printing plate material according to any one of claims 1 to 3, wherein the water-soluble polymer compound is a polymer compound having vinylpyrrolidone as a constituent monomer unit. A method for preparing a lithographic printing plate, comprising subjecting the photosensitive lithographic printing plate material for water development according to claims 1 to 4 to image exposure, heat treatment, and development treatment with water in this order. A method for preparing a lithographic printing plate, wherein the lithographic printing plate obtained by the method for preparing a lithographic printing plate according to claim 5 is further treated with a plate surface protective agent containing a water-soluble resin and a surfactant. The lithographic printing plate preparation method according to claim 5 or 6, wherein the image exposure is performed by a laser having an emission wavelength of 370 nm or more and 420 nm or less.