JP2008175873A - Photosensitive lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate material suitable for exposure with laser light of which the emission wavelength is particularly in a range of 350-450 nm, having high sensitivity and excellent in dot reproducibility. <P>SOLUTION: The photosensitive lithographic printing plate material has, on a support, a photosensitive layer containing (A) a polymerization initiator, (B) a polymerizable compound containing an ethylenic double bond, (C) a sensitizing dye and (D) a polymer binder, wherein the photosensitive layer contains a compound represented by the general formula (1): Q-(I)<SB>n</SB>(wherein I represents formula I<SB>1</SB>or I<SB>2</SB>) and contains a biimidazole compound as the polymerization initiator (A). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photosensitive lithographic printing plate material used in a computer-to-plate system (hereinafter referred to as CTP), and more particularly to a photosensitive lithographic printing plate material suitable for exposure with a laser beam having a wavelength of 350 to 450 nm.

  In recent years, CTP recording digital image data directly on a photosensitive lithographic 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, as described in JP-A-1-105238 and JP-A-2-127404, a polymerization type containing a polymerizable compound is used. It is known to use a negative photosensitive lithographic printing plate material having a photosensitive layer.

  Furthermore, there is known a printing plate material capable of image exposure with a laser having a wavelength of 390 nm to 430 nm, which has improved safe light properties from the viewpoint of handleability of the printing plate.

  And, a high-power and small-sized blue-violet laser with a wavelength of 390 to 430 nm can be easily obtained, and by developing a photosensitive lithographic printing plate suitable for this laser wavelength, a bright room has been developed. (For example, see Patent Documents 1, 2, and 3.)

  Furthermore, a printing plate material containing biimidazole in the photosensitive layer with improved safelight properties under yellow light is known, and it is further known that the photosensitive layer contains a specific thiol compound (Patent Document 4). reference).

However, these printing plate materials also have problems such as insufficient sensitivity, and characters may be crushed when there are missing characters, maintaining high sensitivity and good dot reproducibility. It was difficult to keep.
JP 2000-35673 A JP 2000-98605 A JP 2001-264978 A JP-A-1-279903

  An object of the present invention is to provide a photosensitive lithographic printing plate material that is particularly suitable for exposure with laser light having an emission wavelength in the range of 350 nm to 450 nm, has high sensitivity, and is excellent in halftone dot reproducibility.

The above object of the present invention is achieved by the following means.
1. Photosensitive having a photosensitive layer containing (A) a polymerization initiator, (B) a polymerizable ethylenic double bond-containing compound, (C) a sensitizing dye, and (D) a polymer binder on a support. A lithographic printing plate material, wherein the photosensitive layer contains a compound represented by the following general formula (1), and (A) a biimidazole compound as a polymerization initiator.

Formula (1) Q- (I) _n
[Wherein, I represents I ₁ or I ₂ below.

Q represents an n-valent substituent. n represents an integer of 2 to 4. R ₁ and R ₂ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ₃ represents an alkyl group having 1 to ₃ carbon atoms. R ₄ represents a monovalent substituent. m represents an integer of 0 to 4. R ₅ represents an alkyl group having 1 to 3 carbon atoms. ]
2. 2. The photosensitive lithographic printing plate material according to 1, wherein the photosensitive layer contains 0.1 to 10% by mass of the compound represented by the general formula (1) with respect to the photosensitive layer.
3. The photosensitive lithographic printing plate material according to 1 or 2, wherein the photosensitive layer contains 2.0 to 7.0% by mass of the polymerization initiator (A) with respect to the photosensitive layer.

  With the above configuration of the present invention, it is possible to provide a photosensitive lithographic printing plate material that is particularly suitable for exposure with a laser beam having an emission wavelength in the range of 350 nm to 450 nm, has high sensitivity, and has excellent dot reproducibility.

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  The present invention relates to a photosensitive layer containing (A) a polymerization initiator, (B) a polymerizable ethylenic double bond-containing compound, (C) a sensitizing dye, and (D) a polymer binder on a support. In the photosensitive lithographic printing plate material, the photosensitive layer contains a compound represented by the general formula (1), and (A) a biimidazole compound as a polymerization initiator.

  In the present invention, particularly by using the compound represented by the general formula (1) and using biimidazole as a polymerization initiator, it is suitable for exposure with a laser beam having an emission wavelength in the range of 350 nm to 450 nm and has high sensitivity. Thus, a photosensitive lithographic printing plate material having excellent dot reproducibility can be provided.

(Compound represented by the general formula (1))
In the formula, I represents the following I ₁ or I ₂ .

Q represents an n-valent substituent. n represents an integer of 2 to 4. R ₁ and R ₂ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ₃ represents an alkyl group having 1 to ₃ carbon atoms. R ₄ represents a monovalent substituent. m represents an integer of 1 to 4. R ₅ represents an alkyl group having 1 to 3 carbon atoms.

As the divalent to tetravalent substituent represented by Q, a group bonded to I ₁ or I ₂ via a carbon atom, an oxygen atom, or a nitrogen atom can be used.

  Examples of the divalent substituent include an alkylene group having 1 to 12 carbon atoms, an alkylene group having a substituent having 1 to 12 carbon atoms, and the following groups.

  As a trivalent substituent,

  As a tetravalent substituent,

Is mentioned.

  Of these, Q according to the present invention is particularly preferably a divalent or trivalent substituent in terms of sensitivity and halftone dot reproducibility, and has a saturated hydrocarbon group having 1 to 6 carbon atoms and an ethylene oxide chain. Is preferred.

Examples of the alkyl group for R ₁ and R ₂ include a methyl group, an ethyl group, and a propyl group, and a mail group is preferable. As R ₁ and R ₂ , it is a preferred embodiment that R ₁ and R ₂ are both hydrogen atoms.

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ₃ include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

  Among these, a methyl group is particularly preferably used.

Examples of the monovalent substituent for R ₄ include a halogen atom, a methyl group, an ethyl group, and an ester group. R ₄ is preferably m = 0.

R ₅ represents the same alkyl group as R ₃ .

  The compound represented by the general formula (1) is obtained by an esterification reaction between a mercap group-containing carboxylic acid and a polyhydric alcohol having a structure represented by Q. The esterification reaction itself is known and may be reacted according to a conventional method to give an ester. The conditions for the esterification reaction are not particularly limited, and conventionally known reaction conditions are appropriately selected.

  Specific examples of the compound represented by the general formula (1) according to the present invention are shown below, but are not limited thereto.

  The content of the compound represented by the general formula (1) according to the present invention with respect to the photosensitive layer is preferably 0.1% by mass to 10.0% by mass, particularly 0.15% by mass to 1.0% by mass. Is preferred.

  Moreover, the ratio of content with a biimidazole compound is a ratio with a preferable ratio of 1: 65-1: 5 as a ratio of the compound of general formula (1): biimidazole compound.

((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. In the present invention, the photosensitive layer contains a biimidazole compound as a polymerization initiator. .

  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.

  As a polymerization initiator, other polymerization initiators may be included in addition to the biimidazole compound.

  Examples of these polymerization initiators include titanocene compounds, monoalkyltriaryl borate compounds, iron arene complex compounds, and polyhalogen compounds.

  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 (11) 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 (12) is particularly preferably used.

Formula (11) 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 (12) 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 0.1% by mass to 20% by mass and preferably 0.5% by mass to 15% with respect to the polymerizable ethylenically unsaturated bond-containing compound. Mass% is particularly preferred.

  Moreover, as content with respect to a photosensitive layer, 1 mass%-10 mass% are preferable, and 2 mass%-6 mass% are especially preferable.

((B) Polymerizable, ethylenic double bond-containing compound)
The polymerizable (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 polymerization initiator in the image-exposed photosensitive layer.

In the present invention, as the polymerizable ethylenic double bond-containing compound, the reaction products of the following compounds (C1) to (C3) are particularly preferably used.
(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.

Examples of C2 include 1,3-bis (1-isocyanato-1-methylethyl) benzene (2 mol), 1,3-diisocyanatobenzene, 1,3-diisocyanate-4-methylbenzene, 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 (2) is particularly preferably used.

In general formula (2), R ¹ represents a hydrogen atom or a methyl group. X ¹ represents a divalent aliphatic group. X ² represents a divalent hydrocarbon group or a divalent aliphatic 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 (3) include the following compounds.

  (B) As the polymerizable ethylenic double bond-containing compound, there are a plurality of general radical polymerizable monomers and a plurality of ethylenic double bonds capable of addition polymerization in a molecule generally used for ultraviolet curable resins. The polyfunctional monomers and polyfunctional oligomers possessed 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.

((C) sensitizing dye)
The photosensitive layer according to the present invention contains (C) a sensitizing dye. In the present invention, a sensitizing dye having an absorption maximum in the wavelength range of 350 to 450 nm is preferably used as the sensitizing dye.

  The sensitizing dye having an absorption maximum in the wavelength range of 350 to 450 nm is not particularly limited in terms of structure. Polyene, azo compound, diphenylmethane, triphenylmethane, polymethine acridine, coumarin, coumarin derivatives, ketocoumarin, quinacridone, indigo, styryl, pyrylium compounds, pyromethene compounds, pyrazolotriazole compounds, benzothiazole compounds, stilbenes, distyrylbenzenes, Distyrylbiphenyls, divinylstilbenes, triazinylaminostilbenes, stilbenyltriazoles, stilbenylnaphthotriazoles, bis Triazolestilbenes, benzoxazoles, bisphenylbenzoxazoles, stilbenylbenzoxazoles, bis-benzoxazoles, furans, benzofurans, bis-benzimidazoles, diphenylpyrazolines, diphenyloxa Diazoles, naphthalimides, xanthenes, carbostyrils, pyrenes and 1,3,5-triazinyl-derivatives, barbituric acid derivatives, thiobarbituric acid derivatives, etc., and dye groups such as ketoalcohol borate complexes, Any of them can be used as long as the absorption maximum satisfies the requirement.

  Specifically, Japanese Patent Application Laid-Open Nos. 2002-296664, 2002-268239, 2002-268238, 2002-268204, 2002-221790, 2002-202598, 2001 -042524, JP-A 2000-309724, JP-A 2000-258910, JP-A 2000-206690, JP-A 2000-147763, JP-A 2000-098605, JP-A 2003-295426, etc. However, the present invention is not limited to this. Coumarin derivatives and distyrylbenzenes are particularly preferred.

((D) polymer binder)
The polymer binder according to the present invention is capable of supporting the components contained in the photosensitive layer on a support. Examples of the polymer binder include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, Polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, shellac, and other natural resins can be used. Two or more of these may be used in combination.

  A vinyl copolymer obtained by copolymerization of acrylic monomers is preferred. Furthermore, the copolymer composition of the polymer binder is preferably a copolymer of (a) a carboxyl group-containing monomer, (b) a methacrylic acid alkyl ester, or an acrylic acid alkyl ester.

  Specific examples of the carboxyl group-containing monomer include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride and the like. In addition, carboxylic acids such as phthalic acid and 2-hydroxymethacrylate half ester are also preferable.

  Specific examples of alkyl methacrylates and alkyl esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate. , Decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, acrylic In addition to unsubstituted alkyl esters such as decyl acid, undecyl acrylate and dodecyl acrylate, cyclic alkyl esters such as cyclohexyl methacrylate and cyclohexyl acrylate Substituted alkyl esters such as benzyl methacrylate, 2-chloroethyl methacrylate, N, N-dimethylaminoethyl methacrylate, glycidyl methacrylate, benzyl acrylate, 2-chloroethyl acrylate, N, N-dimethylaminoethyl acrylate, and glycidyl acrylate Also mentioned.

  Further, in the polymer binder, monomers described in the following (1) to (14) can be used as copolymerization monomers.

  1) Monomers having an aromatic hydroxyl group, such as o- (or p-, m-) hydroxystyrene, o- (or p-, m-) hydroxyphenyl acrylate and the like.

  2) Monomers having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N-methylol acrylamide, N-methylol methacrylamide, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 5-hydroxypentyl methacrylate , 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, N- (2-hydroxyethyl) acrylamide, N- (2-hydroxyethyl) methacrylamide, hydroxyethyl vinyl ether and the like.

  3) A monomer having an aminosulfonyl group, such as m- (or p-) aminosulfonylphenyl methacrylate, m- (or p-) aminosulfonylphenyl acrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p -Aminosulfonylphenyl) acrylamide and the like.

  4) Monomers having a sulfonamide group, such as N- (p-toluenesulfonyl) acrylamide, N- (p-toluenesulfonyl) methacrylamide and the like.

  5) Acrylamide or methacrylamides such as acrylamide, methacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N- (4-nitrophenyl) acrylamide, N-ethyl-N- Phenylacrylamide, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide and the like.

  6) Monomers containing fluorinated alkyl groups such as trifluoroethyl acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octafluoropentyl acrylate, octafluoropentyl methacrylate, heptadecafluorodecyl methacrylate, N- Butyl-N- (2-acryloxyethyl) heptadecafluorooctylsulfonamide and the like.

  7) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether and the like.

  8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate and the like.

  9) Styrenes such as styrene, methyl styrene, chloromethyl styrene and the like.

  10) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.

  11) Olefins such as ethylene, propylene, i-butylene, butadiene, isoprene and the like.

  12) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine and the like.

  13) Monomers having a cyano group, such as acrylonitrile, methacrylonitrile, 2-pentenenitrile, 2-methyl-3-butenenitrile, 2-cyanoethyl acrylate, o- (or m-, p-) cyanostyrene.

  14) A monomer having an amino group, such as N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, polybutadiene urethane acrylate, N, N-dimethylaminopropyl acrylamide, N, N-dimethylacrylamide, acryloylmorpholine, Ni-propylacrylamide, N, N-diethylacrylamide and the like.

  Further, other monomers that can be copolymerized with these monomers may be copolymerized.

  Furthermore, the polymer binder is preferably a vinyl polymer having a carboxyl group and a polymerizable double bond in the side chain. For example, an unsaturated bond-containing vinyl copolymer obtained by addition-reacting a compound having a (meth) acryloyl group and an epoxy group in the molecule to a carboxyl group present in the molecule of the vinyl copolymer. Is also preferred as a polymer binder.

  Specific examples of the compound containing both an unsaturated bond and an epoxy group in the molecule include glycidyl acrylate, glycidyl methacrylate, and an epoxy group-containing unsaturated compound described in JP-A No. 11-271969. In addition, an unsaturated bond-containing vinyl copolymer obtained by adding a compound having a (meth) acryloyl group and an isocyanate group in the molecule to a hydroxyl group present in the molecule of the vinyl polymer is also high. Preferred as a molecular binder. Compounds having both an unsaturated bond and an isocyanate group in the molecule include vinyl isocyanate, (meth) acrylic isocyanate, 2- (meth) acryloyloxyethyl isocyanate, m- or p-isopropenyl-α, α'-dimethylbenzyl. Isocyanates are preferred, and (meth) acrylic isocyanate, 2- (meth) acryloyloxyethyl isocyanate and the like can be mentioned.

  The vinyl polymer having a carboxyl group and a polymerizable double bond in the side chain is preferably 50 to 100% by mass, and more preferably 100% by mass in the total polymer binder.

  The content of the polymer binder in the photosensitive layer is preferably in the range of 10 to 90% by mass, more preferably in the range of 15 to 70% by mass, and the use in the range of 20 to 50% by mass from the viewpoint of sensitivity. Particularly preferred.

(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.

  Examples of the solvent used in preparing the photosensitive layer coating solution for the photosensitive layer according to the present invention include, for example, alcohol: polyhydric alcohol derivatives, sec-butanol, isobutanol, n-hexanol, benzyl alcohol, Diethylene glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, ethers: propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ketones, aldehydes: diacetone alcohol, cyclohexanone Preferred examples include methylcyclohexanone and esters: ethyl lactate, butyl lactate, diethyl oxalate, methyl benzoate and the like.

  Although the photosensitive layer coating solution has been described above, the photosensitive layer according to the present invention is formed by coating on a support using the photosensitive layer.

Photosensitive layer according to the present invention as the amount per on the ^{support, 0.1g / m 2 ~10g / m} 2 are preferred, especially 0.5g / m ² ~5g / m ² is preferred.

(Protective layer (oxygen barrier layer))
A protective layer can be provided on the upper side of the photosensitive layer according to the present invention, if necessary.

  This protective layer (oxygen barrier layer) is preferably highly soluble in a developer (described below, generally an aqueous alkali solution) described below, and specific examples include polyvinyl alcohol and polyvinyl pyrrolidone. Polyvinyl alcohol has an effect of suppressing permeation of oxygen, and polyvinyl pyrrolidone has an effect of ensuring adhesion with an adjacent photosensitive layer.

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

  When a protective layer is provided on the photosensitive lithographic printing plate of 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 even more preferably 75 mN / mm or more. is there. Preferred examples of the protective layer composition include those described in Japanese Patent Application No. 8-161645.

  In the present invention, the peeling force is obtained by applying an adhesive tape having a predetermined width on the protective layer and having a sufficiently large adhesive force, and peeling it together with the protective layer at an angle of 90 degrees with respect to the plane of the photosensitive lithographic printing plate material. It can be determined by measuring the force.

  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.

  When providing a protective layer, the thickness 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.

  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.

(Image exposure)
As a light source for recording an image on the photosensitive lithographic printing plate material of the present invention, it is preferable to use a laser beam having an emission wavelength of 370 to 440 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.

(Developer)
The exposed portion of the photosensitive layer subjected to image exposure is cured. This is preferably developed with an alkaline developer to remove unexposed portions and form an image.

  As such a developer, a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium, ammonium; dibasic sodium phosphate, potassium, ammonium; sodium bicarbonate, potassium, ammonium; sodium carbonate, potassium, ammonium; sodium bicarbonate, potassium, ammonium An alkali developer using an inorganic alkaline agent such as sodium borate, potassium, ammonium; sodium hydroxide, potassium, ammonium and lithium;

  Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, mono-i-propylamine, di-i-propylamine, tri-i-propylamine, butylamine, monoethanolamine, diethanolamine, triethanolamine, Organic alkali agents such as mono-i-propanolamine, di-i-propanolamine, ethyleneimine, ethylenediamine, and pyridine can also be used.

  These alkali agents are used alone or in combination of two or more. In addition, an organic solvent such as an anionic surfactant, an amphoteric surfactant or alcohol can be added to the developer as necessary.

  Alkaline developers can also be prepared from developer concentrates such as granules and tablets.

  The developer concentrate may be evaporated to dryness once it is made into a developer, but preferably the materials are mixed by adding a small amount of water without adding water when mixing a plurality of materials. A method of concentrating with is preferable. The developer concentrates are disclosed in JP-A-51-61837, JP-A-2-109042, JP-A-2-109043, JP-A-3-39735, JP-A-5-142786, JP-A-6-266062, and JP-A-7. Granules and tablets can be obtained by a well-known method described in No. 13341 or the like. Further, the developer concentrate may be divided into a plurality of parts having different material types, material mixing ratios, and the like.

  The alkaline developer and its replenisher may further contain preservatives, colorants, thickeners, antifoaming agents, hard water softeners, and the like as necessary.

(Automatic processor)
It is advantageous to use an automatic processor for developing the photosensitive lithographic printing plate material. The automatic developing machine is preferably provided with a mechanism for automatically replenishing the required amount of the developing replenisher to the developing bath, and preferably provided with a mechanism for discharging the developer exceeding a certain amount, preferably the developing bath. Is provided with a mechanism for automatically replenishing the required amount of water, preferably a mechanism for detecting plate passing is provided, preferably a mechanism for estimating the processing area of the plate based on detection of plate passing. Preferably, a mechanism for controlling the replenishment amount and / or replenishment timing of the replenisher and / or water to be replenished based on the detection of the printing plate and / or the estimation of the processing area is provided. Is provided with a mechanism for controlling the temperature of the developer, preferably a mechanism for detecting the pH and / or conductivity of the developer, preferably based on the pH and / or conductivity of the developer. Trying to replenish The amount of replenisher supplied and / or water and / or mechanism for controlling the replenishment timing is given that. The developer concentrate preferably has a function of once diluting and stirring with water. When there is a rinsing step after the development step, the rinsing water after use can be used as dilution water for the concentrate of the development concentrate.

  The automatic processor may have a pretreatment unit that immerses the plate in the pretreatment liquid before the development step. The pretreatment unit is preferably provided with a mechanism for spraying the pretreatment liquid on the plate surface, and preferably provided with a mechanism for controlling the temperature of the pretreatment liquid to an arbitrary temperature of 25 to 55 ° C. Is provided with a mechanism for rubbing the plate surface with a roller-like brush. Water or the like is used as the pretreatment liquid.

(Post-processing)
The lithographic printing plate material developed with an alkaline developer is subjected to post-processing with a washing water, a rinse solution containing a surfactant, a finisher mainly composed of gum arabic or starch derivatives, or a protective gum solution. . These treatments can be used in various combinations. For example, the treatment with a rinsing solution containing development->washing-> surfactant or the development->washing-> finisher solution is preferable because of less fatigue of the rinse solution and the finisher solution. Furthermore, a countercurrent multistage process using a rinse liquid or a finisher liquid is also a preferred embodiment.

  These post-processing are generally performed using an automatic developing machine including a developing unit and a post-processing unit. As the post-treatment liquid, a method of spraying from a spray nozzle or a method of immersing and conveying in a treatment tank filled with the treatment liquid is used. A method is also known in which a fixed amount of a small amount of washing water is supplied to the plate surface after development, and the waste liquid is reused as dilution water for the developer stock solution. In such automatic processing, processing can be performed while each replenisher is replenished with each replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable treatment method in which treatment is performed with a substantially unused post-treatment liquid is also applicable. The lithographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

  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.

(Synthesis of acrylic copolymer 1)
A three-necked flask under a nitrogen stream is charged with 30 parts of methacrylic acid, 50 parts of methyl methacrylate, 20 parts of ethyl methacrylate, 500 parts of isopropyl alcohol and 3 parts of α, α'-azobisisobutyronitrile. The mixture was reacted for 6 hours in an oil bath at 0 ° C. Then, after refluxing at the boiling point of isopropyl alcohol for 1 hour, 3 parts of triethylammonium chloride and 25 parts of glycidyl methacrylate were added and reacted for 3 hours to obtain an acrylic copolymer 1. The weight average molecular weight measured using GPC was about 35,000, and the glass transition temperature (Tg) measured using DSC (differential thermal analysis) was about 85 ° C. (Solid content 20% solution)
(Preparation of support) An aluminum plate (material 1050, tempered H16) having a thickness of 0.3 mm was immersed in a 5% sodium hydroxide aqueous solution kept at 65 ° C., degreased for 1 minute, and then washed with water. did. This degreased aluminum plate was neutralized by dipping in a 10% aqueous hydrochloric acid solution maintained at 25 ° C. for 1 minute, and then washed with water. Next, the aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds under conditions of 25 ° C. and a current density of 100 A / dm ^{2 in} a 0.3% by mass nitric acid aqueous solution, and then kept at 60 ° C. Desmutting treatment was performed for 10 seconds in a 5% aqueous sodium hydroxide solution. The surface-roughened aluminum plate subjected to desmut treatment was anodized in a 15% sulfuric acid solution at 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute, and further 3 mass% polyvinylphosphonic acid. A support was prepared by hydrophilizing at 75 ° C.

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

(Preparation of photosensitive lithographic printing plate material 1)
On the above support, the following photopolymerization photosensitive layer coating solution 1 is applied with a wire bar so that the dry photopolymerization photosensitive layer coating liquid 1 becomes 1.6 g / m ² , dried at 90 ° C. for 2 minutes, and then on the photosensitive layer with the following composition: Photosensitive lithographic printing having an oxygen barrier layer on the photosensitive layer, coated with an applicator so that the oxygen barrier layer coating solution is 1.8 g / m ² when dried and dried at 75 ° C. for 1.5 minutes. A plate material 1 was produced.

(Photopolymerization photosensitive layer coating solution 1)
(A) 2,2′-bis (2-chlorophenyl) -4,5,4 ′, 5′-tetraphenylbisimidazole 4 parts (B) -1 The following compound M-1 (propylene glycol monomethyl having a solid content of 50%) Ether acetate solution) 72 parts (B) -2 dipentaerythritol hexaacrylate 10 parts (B) -3 tetraethylene glycol dimethacrylate 5 parts (C) Dye-1 6 parts below (D) acrylic copolymer 1 (solid) 160 parts (E) Compound (1) -1 0.3 part of the above general formula (1) Pigment dispersion Copper phthalocyanine pigment (MHI # 454 (solid content 35) % Methyl ethyl ketone dispersion): Mikuni Color Co., Ltd.) 14 parts Surfactant Edaplan LA4 1: MUNZING CHEMIE GMBH Co., Ltd.
0.1 part Solvent 1 methyl ethyl ketone 200 parts Solvent 2 propylene glycol monomethyl ether 530 parts (oxygen barrier coating liquid)
Polyvinyl alcohol (AL-06: manufactured by Nippon Synthetic Chemical Co., Ltd.) 89.5 parts Polyvinylpyrrolidone (Rubitec K-30: manufactured by BASF Corp.) 10.0 parts Surfactant (Surfinol 465: manufactured by Nissin Chemical Industry Co., Ltd.) 5 parts Water 900 parts

(Evaluation of planographic printing plate materials)
(sensitivity)
The photosensitive lithographic printing plate material was exposed at 2400 dpi (dpi represents the number of dots per 2.54 cm) using a plate setter (NewsCTP: manufactured by ECRM) equipped with a light source of 405 nm and 60 mW. .

  As the exposure pattern, original image data having a 100% image portion, a 50% halftone dot image portion, a Times New Rohman font, a size of 3 to 10 points, and a letter without alphabetic capital letters and lowercase letters was used.

  Next, a preheating section set at 105 ° C., a pre-water washing section for removing the oxygen blocking layer, a developing solution having the following composition are filled, and the developing section whose temperature is adjusted to 30 ° C. and the developing solution adhering to the plate surface are removed. Developed with a CTP automatic processor (Raptor Polymer 85: Glunz & Jensen) equipped with a processing unit for gum washing (GW-3: manufactured by Mitsubishi Chemical Co., Ltd., twice diluted) for protecting the water washing part and the image line part, A lithographic printing plate was obtained.

(Developer composition (aqueous solution containing the following additives))
A Potassium silicate 8.0 parts New Coal B-13SN: Nippon Emulsifier Co., Ltd. 3.0 parts Water 89.0 parts Caustic potash pH = 12.0 100% recorded on the plate surface of the lithographic printing plate In the image area, the exposure energy when the reflection density based on the grained surface of the non-image area is 95% or more as compared with the reflection density of the photosensitive layer before development is used as recording energy, and is used as an index of sensitivity. The reflection densitometer used was D-196 manufactured by Gretag Macbeth. The smaller the recording energy, the higher the sensitivity.

(Evaluation of halftone dot reproducibility)
The lithographic printing plate obtained by the above development is coated with a printing machine (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), printing ink (soybean oil ink “Naturalis 100” manufactured by Dainippon Ink & Chemicals, Inc.). And fountain solution (Tokyo Ink Co., Ltd. H liquid SG-51 concentration 1.5%) was printed 1000 sheets, and the halftone dot on the plate was measured with X-rite Dot (manufactured by X-rite). . A dot area ratio of 50% or more and less than 60% was evaluated as ◯, 60% or more and less than 68% as Δ, 68% or more as less than 50% as ×.

(Preparation of photosensitive lithographic printing plate materials 2-17)
Except for changing the general formula (1) compound (1) -1 of the photosensitive lithographic printing plate material 1 to (1) -2 to (1) -17, respectively, Produced.

  Further, as a comparative material, the compound of the general formula (1) (1) -1 of the photosensitive lithographic printing plate material 1 is changed to the following compound (3) -1 to form a photosensitive lithographic plate in the same process as the printing plate material 1. A photosensitive lithographic printing plate material 18 was prepared.

(Preparation of photosensitive lithographic printing plate materials 19 to 24)
Photosensitive lithographic printing plate materials 19 to 24 were prepared in the same manner as photosensitive lithographic printing plate material 1 using photopolymerized photosensitive layer coating solutions 19 to 24 having the compositions shown in Table 2 below. Evaluation similar to the above was performed about the photosensitive lithographic printing plate materials 2-24. The results are shown in Table 3.

  It can be seen from Table 3 that the photosensitive lithographic printing plate material using the photosensitive composition of the present invention has high sensitivity and excellent halftone dot reproducibility. (Numbers without units in the table represent parts by mass)

Claims (3)

Photosensitive having a photosensitive layer containing (A) a polymerization initiator, (B) a polymerizable ethylenic double bond-containing compound, (C) a sensitizing dye, and (D) a polymer binder on a support. A lithographic printing plate material, wherein the photosensitive layer contains a compound represented by the following general formula (1), and (A) a biimidazole compound as a polymerization initiator.
Formula (1) Q- (I) _n
[Wherein, I represents I ₁ or I ₂ below.

Q represents an n-valent substituent. n represents an integer of 2 to 4. R ₁ and R ₂ represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ₃ represents an alkyl group having 1 to ₃ carbon atoms. R ₄ represents a monovalent substituent. m represents an integer of 0 to 4. R ₅ represents an alkyl group having 1 to 3 carbon atoms. ] The photosensitive lithographic printing plate material according to claim 1, wherein the photosensitive layer contains 0.1 to 10% by mass of the compound represented by the general formula (1) with respect to the photosensitive layer. The photosensitive lithographic printing plate material according to claim 1, wherein the photosensitive layer contains the polymerization initiator (A) in an amount of 2.0 to 7.0% by mass with respect to the photosensitive layer.