JP4714650B2 - Photopolymerization type photosensitive lithographic printing plate precursor - Google Patents

Description

  The present invention relates to a negative photopolymerization type photosensitive lithographic printing plate precursor that can be directly drawn with a laser beam, and particularly to a negative type photopolymerization type photosensitive lithographic printing plate precursor suitable for high-definition AM screen printing and FM screen printing. About.

Conventionally, a lithographic printing plate is a photosensitive lithographic printing plate having a constitution in which a photosensitive resin layer is provided on a support having a hydrophilic surface, usually after surface exposure (mask exposure) via a lithographic film, It was obtained by a plate making method in which non-image areas were removed with a developer. However, with recent digitization technology, a computer toe that directly exposes the plate without using a lith film by scanning the plate with highly directional light such as laser light according to the digitized image information. Plate (CTP) technology has been developed, and photosensitive lithographic printing plates adapted to this have been developed.
Examples of the photosensitive lithographic printing plate suitable for exposure with laser light include a photosensitive lithographic printing plate using a polymerizable photosensitive layer. This is because the polymerizable photosensitive layer can be easily increased in sensitivity as compared with other conventional photosensitive layers by selecting a photopolymerization initiator or a polymerization initiator system (hereinafter also simply referred to as an initiator or an initiator system).

However, since the photosensitive lithographic printing plate as described above is drawn with a laser beam, the edge of the image depends on the shape of the energy distribution of the laser beam, and an insufficiently polymerized region is formed due to an insufficient exposure amount. . For this reason, the sharpness of the image edge is impaired, leading to a decrease in resolution. In addition, such poorly polymerized image edges have poor removal due to the alkali concentration of the developer and the state of the developing brush in the development processing step, and the in-plane variation in the halftone dot area of the plate making plate is increased. It was.
Furthermore, since such a printing plate uses a support having irregularities formed on the surface by electrolytic treatment or brushing to ensure hydrophilicity as a support, it is further caused by scattering of reflected light during laser exposure. The image quality and sharpness are impaired, and the reproducibility of the shadow part is greatly reduced.

  On the other hand, in recent years, the demand for high-definition AM screen printing and FM screen printing has increased in the CTP technology, and the resolution of the planographic printing plate precursor has become an important performance.

  An FM (Frequency Modulation) screen is one in which minute halftone dots of about 20 microns are randomly arranged regardless of the screen angle and the number of lines, and density gradation is expressed by the density of halftone dots per unit area. This FM screen print has the following characteristics: no interference moire or rosette pattern occurs, no tone jump occurs in a halftone area near a halftone dot area ratio of 50%, and halftone dots are small, so there is little overlap between halftone dots. The reproduced color looks vivid.

  An AM (Amplitude Modulation) screen is a screen in which halftone dots are regularly arranged at an angle with respect to the FM screen and the density gradation is expressed by the size of the halftone dots per unit area. A typical AM screen in Japan has 175 lines per inch. On the other hand, what uses a screen line number of 200 lines or more is generally called high definition.

  Features of high-definition printed materials include a reduction in moire and rosetta patterns, an improvement in image texture, a sense of existence, and an improvement in reproducibility of details.

  However, a photosensitive material that reduces the reproducibility of a shadow part, such as a lithographic printing plate precursor using the above polymerizable photosensitive layer, provides a printing plate suitable for FM screen and high-definition AM screen printing. In this case, it was difficult to reproduce a very small halftone dot.

Patent Document 1 discloses a photosensitive printing plate having a support having a surface to which a functional group capable of causing an addition reaction by a radical is bonded by a covalent bond, and a photopolymerizable photosensitive layer provided on the surface. A photosensitive printing plate is disclosed in which the photopolymerizable photosensitive layer contains a photoinitiator and a sensitizer having an absorption wavelength of 400 to 1000 nm, and the bonding of the addition-reactive functional group to the support surface is an organic silicone. It is described that it is preferable to use a compound as a raw material.
However, although the technique disclosed in Patent Document 1 can provide a plate material suitable for high-definition AM screen printing and FM screen printing, a phenomenon called dot loss in which halftone dots become thin occurs or an automatic processor is provided. It has been found that there is room for improvement, such as development reproducibility being impaired by the pressure of the developed developing brush, and so-called brush pressure dependency.
Japanese Patent Laid-Open No. 7-159983

  Therefore, the object of the present invention is to suppress dot loss and brush pressure dependency, enable excellent halftone dot reproducibility, and also enable generation of waste during development processing and reduction of aluminum elution into the developer. In particular, a negative photopolymerization type photosensitive lithographic printing plate precursor suitable for high-definition AM screen printing and FM screen printing is provided.

  The present invention is as follows.

  (1) An intermediate layer containing a metal oxide obtained by hydrolysis and polycondensation of an organometallic compound or an inorganic metal compound is provided on a hydrophilic support, and the following formula (1) ( A negative photopolymerizable photosensitive lithographic printing plate precursor comprising a photopolymerizable photosensitive layer containing a binder polymer having the structural unit represented by 3) and a protective layer containing a water-soluble resin.

In the formula, each of R ₁ and R ₂ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ₃ represents a substituted alkyl group having 1 to 6 carbon atoms substituted with a hydroxyl group, and X represents _{-COOH, -CO-W} 1 -L represents a functional group selected from 1 -COOH and -SO ₃ H, _{W 1} represents an oxygen atom, a sulfur atom or -NH- group, _{L 1} is a divalent organic group Y represents —CO—O—CH ₂ —CH═CH ₂ group, —CO—W ₂ —L ₂ —O—CO—CR ₄ ═CH ₂ group, and W ₂ represents oxygen atom, sulfur atom or —NH— group, L ₂ represents a divalent organic group, R ₄ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, W ₃ represents an oxygen atom, a sulfur atom or a —NH— group. , _{R 5} is an alkyl group having an alkyl group having 1 to 18 carbon atoms, an alicyclic structure having from 5 to 20 carbon atoms A group having an aromatic ring prime 6-20.
(2) The negative photopolymerizable photosensitive lithographic plate according to (1), wherein the intermediate layer containing the metal oxide contains an organosilicone compound having a functional group capable of causing addition polymerization by radicals. A printing plate master.
(3) The negative photopolymerizable photosensitive lithographic printing plate precursor as described in (1) above, wherein the photopolymerizable photosensitive layer contains the following components (i) to (v):
(I) a sensitizing dye having an absorption maximum in a wavelength range of 350 nm to 450 nm,
(Ii) hexaarylbiimidazole compound,
(Iii) an addition polymerizable compound having an ethylenically unsaturated double bond,
(Iv) The binder polymer according to (1), and (v) at least one selected from 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzoimidazole, and a compound represented by the following formula (4) Compound.

In the formula, R ₆ represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms, or a group having an aromatic ring having 6 to 20 carbon atoms. X represents an oxygen atom, a sulfur atom or —N (R ₇ ) —, wherein R ₇ is a linear or branched alkyl group having 1 to 18 carbon atoms, or an alkyl having an alicyclic structure having 5 to 20 carbon atoms. A group or a group having an aromatic ring having 6 to 20 carbon atoms is shown.

  The photopolymerization type photosensitive lithographic printing plate precursor of the present invention suppresses dot loss and brush pressure dependency, and enables excellent halftone dot reproducibility, that is, extremely fine halftone dot reproducibility. Further, the generation of residue of the photosensitive layer component during development processing is reduced. Furthermore, the amount of aluminum eluted into the developer is small, thereby reducing the production of aluminum hydroxide and improving the maintainability of the automatic processor.

Hereinafter, the present invention will be described in more detail. The present invention relates to the negative type photopolymerization type photosensitive lithographic printing plate precursor described in the above (1) to (3), but in this specification, other matters are also described for reference. To do.
(Photosensitive layer)
The photosensitive layer in the lithographic printing plate precursor according to the invention must contain the (D) binder polymer having the structural unit represented by the above formulas (1) to (3). It is desirable to contain a sensitizing dye having a maximum absorption in a wavelength range of 350 to 450 nm, (B) a polymerization initiator, (C) a polymerizable compound, and (E) a mercapto compound.
Hereinafter, the components of the photosensitive layer will be described in detail.

(A) Sensitizing dye The photosensitive layer of the present invention may contain a sensitizing dye corresponding to the wavelength of the exposure light source.
First, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described. Examples of such a sensitizing dye include merocyanine dyes represented by the following general formula (V), benzopyrans and coumarins represented by the following general formula (VI), and fragrances represented by the following general formula (VII). And anthracenes represented by the following general formula (VIII).

(In the formula, A represents an S atom or NR ₆ , R ₆ represents a monovalent non-metallic atomic group, Y represents a basic nucleus of the dye in cooperation with the adjacent A and the adjacent carbon atom. A non-metallic atomic group, X ₁ and X ₂ each independently represent a monovalent non-metallic atomic group, and X ₁ and X ₂ may combine with each other to form an acidic nucleus of the dye.)

(In the formula, = Z represents a carbonyl group, a thiocarbonyl group, an imino group or an alkylidene group represented by the partial structural formula (1 ′), and X ₁ and X ₂ have the same meanings as in the general formula (V). R _{7 to} R ₁₂ each independently represents a monovalent nonmetallic atomic group.)

(In the formula, Ar ₃ represents an aromatic group or a heteroaromatic group which may have a substituent, and R ₁₃ represents a monovalent non-metallic atomic group. More preferable R ₁₃ represents an aromatic group or It is a heteroaromatic group, and Ar ₃ and R ₁₃ may be bonded to each other to form a ring.)

(In the formula, X ₃ , X ₄ and R _{14 to} R ₂₁ each independently represent a monovalent non-metallic atomic group, and more preferable X ₃ and X ₄ are electron donating groups having a negative Hammett's substituent constant. .)

In the general formulas (V) to (VIII), preferred examples of the monovalent nonmetallic atomic group represented by X ₁ to X ₄ and R ₆ to R ₂₁ include a hydrogen atom, an alkyl group (for example, a methyl group, Ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, hexadecyl group, octadecyl group, eicosyl group, isopropyl group, isobutyl group , S-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group, 2-norbornyl group, chloromethyl group , Bromomethyl group, 2-chloroethyl group, trifluoromethyl group, methoxymethyl group, methoxy ester Toxiethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N-cyclohexylcarbamoyloxyethyl Group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbonylethyl group, allyloxycarbonylbutyl group, chloro Phenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, -Methyl-N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfa Moylpropyl group, N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methyl Phosphonatobutyl group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonatoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group P-methylbenzyl group , Cinnamyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc.), aryl group ( For example, phenyl group, biphenyl group, naphthyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group , Acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylaminophenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl Phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group, cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl group, phosphonatophenyl group, etc.), heteroaryl group (for example, thiophene, thiathrene) , Furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indoyl, indazole, purine, quinolidine, isoquinoline, phthalazine , Naphthyridine, quinazoline, cynoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthroline, phthalazine, phenalzadi , Phenoxazine, furazane, phenoxazine, etc.), alkenyl group (eg, vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group, etc.), alkynyl group (eg, ethynyl group) 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group, etc.), halogen atom (-F, -Br, -Cl, -I), hydroxyl group, alkoxy group, aryloxy group, mercapto group, alkylthio group, arylthio group Alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino group, N-alkyl-N-arylamino group, Acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcal Vamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group, N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy group, arylsulfoxy group, acylthio group, acylamino group, N- Alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-arylureido group, N ′, N′-diarylureido group, N '-Alkyl-N'-arylureido group, N-alkylureido group, N-arylureido group, N'-alkyl-N-alkylureido group, N'-alkyl-N-arylureido group, N', N ' -Dialkyl-N-alkylureido groups, N ', N'-dialkyl-N-arylurees Group, N′-aryl-N-alkylureido group, N′-aryl-N-arylureido group, N ′, N′-diaryl-N-alkylureido group, N ′, N′-diaryl-N-aryl Ureido group, N′-alkyl-N′-aryl-N-alkylureido group, N′-alkyl-N′-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl- N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl group , Alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-al Rucarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group , Sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N-alkylsulfinamoyl group, N, N-dialkylsulfina Moyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfur group Famoyl group, N-a A reelsulfamoyl group, an N, N-diarylsulfamoyl group, an N-alkyl-N-arylsulfamoyl group, a phosphono group (—PO ₃ H ₂ ) and a conjugate base group thereof (hereinafter referred to as a phosphonate group), Dialkyl phosphono group (—PO ₃ (alkyl) ₂ ), diaryl phosphono group (—PO ₃ (aryl) ₂ ), alkylaryl phosphono group (—PO ₃ (alkyl) (aryl)), monoalkyl phosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonate group), monoarylphosphono group (—PO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as arylphosphonate) referred to as group), phosphonooxy group (-OPO ₃ H ₂₎ and its conjugated base group (hereinafter referred to as phosphonophenyl group , Dialkyl phosphonooxy group _{(-OPO 3 (alkyl) 2)} , diaryl phosphonooxy group _{(-OPO 3 (aryl) 2)} , alkylaryl phosphonooxy group _{(-OPO 3 (alkyl) (aryl} )), mono Alkylphosphonooxy group (—OPO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkylphosphonateoxy group), monoarylphosphonooxy group (—OPO ₃ H (aryl)) and its conjugate base Groups (hereinafter referred to as arylphosphonatooxy groups), cyano groups, nitro groups, and the like. Among the above substituents, hydrogen atoms, alkyl groups, aryl groups, halogen atoms, alkoxy groups, and acyl groups are particularly preferred. preferable.

  Examples of the basic nucleus of the dye formed together with A adjacent to Y in the general formula (V) and the adjacent carbon atom include 5-, 6-, and 7-membered nitrogen-containing or sulfur-containing heterocycles. A 5- or 6-membered heterocyclic ring is preferable.

Examples of nitrogen-containing heterocycles include L. G. Brooker et al. , J. et al. Am. Chem. Soc. 73, 5326-5358 (1951). Any of those known to constitute a basic nucleus in the merocyanine dyes described in the literature and the references can be suitably used. Specific examples include thiazoles (for example, thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4,5- Di (p-methoxyphenylthiazole), 4- (2-thienyl) thiazole, etc.), benzothiazoles (for example, benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-chlorobenzothiazole, 7- Chlorobenzothiazole, 4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzo Cheer , 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-di Oxymethylenebenzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzothiazole, 6-dimethylaminobenzothiazole, 5-ethoxycarbonylbenzothiazole, etc.), naphthothiazoles (for example, naphtho [1,2] thiazole, naphtho [2 , 1] thiazole, 5-methoxynaphtho [2,1] thiazole, 5-ethoxynaphtho [2,1] thiazole, 8-methoxynaphtho [1,2] thiazole, 7-methoxynaphtho [1,2] thiazole, etc.) , Chianafuteno 7 ′, 6 ′, 4,5-thiazole (for example, 4′-methoxythianaphtheno-7 ′, 6 ′, 4,5-thiazole, etc.), oxazole (for example, 4-methyloxazole, 5-methyloxazole) 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, etc.), benzoxazoles (benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole) , 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 6-methoxybenzoxazole, 5-methoxybenzoxazole, 4-ethoxybenzoxazole, 5-chloro Benzoki Sol, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), naphthoxazoles (eg, naphtho [1,2] oxazole, naphtho [2,1] oxazole, etc.), selenazoles (eg, , 4-methylselenazole, 4-phenylselenazole, etc.), benzoselenazoles (for example, benzoselenazole, 5-chlorobenzoselenazole, 5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselena) Sol etc.), naphthoselenazoles (eg naphtho [1,2] selenazole, naphtho [2,1] selenazole etc.), thiazolines (eg thiazoline, 4-methylthiazoline etc.), 2-quinolines (eg Quinoline, 3-methyl Norin, 5-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-chloroquinoline, 8-chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), 4 -Quinolines (eg, quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-methylquinoline, etc.), 1-isoquinolines (eg, isoquinoline, 3,4-dihydroisoquinoline, etc.), 3-isoquinolines (eg, , Isoquinoline, etc.), benzimidazoles (eg, 1,3-diethylbenzimidazole, 1-ethyl-3-phenylbenzimidazole, etc.), 3,3-dialkylindolenins (eg, 3,3-dimethylindolenin, 3,3,5, -trimethylindolenine, 3,3,7,- Trimethylindolenine etc.), 2-pyridines (eg pyridine, 5-methylpyridine etc.), 4-pyridine (eg pyridine etc.) and the like.

Examples of the sulfur-containing heterocycle include a dithiol partial structure in dyes described in JP-A-3-296759.
Specific examples include benzodithiols (for example, benzodithiol, 5-t-butylbenzodithiol, 5-methylbenzodithiol, etc.), naphthodithiols (for example, naphtho [1,2] dithiol, naphtho [2,1] Dithiol etc.), dithiols (for example, 4,5-dimethyldithiols, 4-phenyldithiols, 4-methoxycarbonyldithiols, 4,5-dimethoxycarbonylbenzodithiols, 4,5-ditrifluoromethyldithiol, 4 , 5-dicyanodithiol, 4-methoxycarbonylmethyldithiol, 4-carboxymethyldithiol and the like.

  As mentioned above, for the sake of convenience, the description used in the description of the heterocyclic ring has conventionally used the name of the heterocyclic mother skeleton, but when forming the basic skeleton partial structure of the sensitizing dye, for example, in the case of the benzothiazole skeleton It is introduced in the form of an alkylidene-type substituent with one degree of unsaturation, such as a 3-substituted-2 (3H) -benzothiazolidene group.

  Among the sensitizing dyes having an absorption maximum in the wavelength range of 350 nm to 450 nm, a dye more preferable from the viewpoint of high sensitivity is a dye represented by the following general formula (IX).

(In General Formula (IX), A represents an aromatic ring or a hetero ring which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represents a hydrogen atom or a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be.)

General formula (IX) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, substituted or non-substituted It represents a substituted aryl group, a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxyl group, and a halogen atom.

Preferable examples of R ₁ , R ₂ and R ₃ will be specifically described. Examples of preferable alkyl groups include linear, branched, and cyclic alkyl groups having 1 to 20 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, Butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, octadecyl, eicosyl, isopropyl, isobutyl, s-butyl, Examples thereof include t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, cyclopentyl group and 2-norbornyl group. Of these, linear alkyl groups having 1 to 12 carbon atoms, branched alkyl groups having 3 to 12 carbon atoms, and cyclic alkyl groups having 5 to 10 carbon atoms are more preferable.

As the substituent of the substituted alkyl group, a monovalent nonmetallic atomic group excluding a hydrogen atom is used. Preferred examples include halogen atoms (—F, —Br, —Cl, —I), hydroxyl groups, and alkoxy groups. , Aryloxy group, mercapto group, alkylthio group, arylthio group, alkyldithio group, aryldithio group, amino group, N-alkylamino group, N, N-dialkylamino group, N-arylamino group, N, N-diarylamino Group, N-alkyl-N-arylamino group, acyloxy group, carbamoyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, N, N-dialkylcarbamoyloxy group, N, N-diarylcarbamoyloxy group N-alkyl-N-arylcarbamoyloxy group, alkylsulfoxy , Arylsulfoxy group, acylthio group, acylamino group, N-alkylacylamino group, N-arylacylamino group, ureido group, N′-alkylureido group, N ′, N′-dialkylureido group, N′-aryl Ureido group, N ′, N′-diarylureido group, N′-alkyl-N′-arylureido group, N-alkylureido group, N-arylureido group, N′-alkyl-N-alkylureido group, N ′ -Alkyl-N-arylureido group, N ', N'-dialkyl-N-alkylureido group, N', N'-dialkyl-N-arylureido group, N'-aryl-N-alkylureido group, N ' -Aryl-N-arylureido group, N ', N'-diaryl-N-alkylureido group, N', N'-diaryl-N- Lilleureido group, N'-alkyl-N'-aryl-N-alkylureido group, N'-alkyl-N'-aryl-N-arylureido group, alkoxycarbonylamino group, aryloxycarbonylamino group, N-alkyl -N-alkoxycarbonylamino group, N-alkyl-N-aryloxycarbonylamino group, N-aryl-N-alkoxycarbonylamino group, N-aryl-N-aryloxycarbonylamino group, formyl group, acyl group, carboxyl Group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group, N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N, N-diarylcarbamoyl group, N-alkyl-N-arylcarbamoyl Group, alkyl Sulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfo group (—SO ₃ H) and its conjugate base group (hereinafter referred to as sulfonate group), alkoxysulfonyl group, aryloxysulfonyl group, sulfinamoyl group, N -Alkylsulfinamoyl group, N, N-dialkylsulfinamoyl group, N-arylsulfinamoyl group, N, N-diarylsulfinamoyl group, N-alkyl-N-arylsulfinamoyl group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group, N-arylsulfamoyl group, N, N-diarylsulfamoyl group, N-alkyl-N-arylsulfamoyl group, phosphono group (-PO ₃ H ₂₎ and its conjugated base group (hereinafter, phosphorylase Onato referred to as group), dialkyl phosphono group _{(-PO 3 (alkyl) 2)} , diaryl phosphono group _{(-PO 3 (aryl) 2)} , alkyl aryl phosphono group _{(-PO 3 (alkyl) (aryl} )) , Monoalkyl phosphono group (—PO ₃ H (alkyl)) and its conjugate base group (hereinafter referred to as alkyl phosphonate group), monoaryl phosphono group (—PO ₃ H (aryl)) and its conjugate base group (Hereinafter referred to as aryl phosphonate group), phosphonooxy group (—OPO ₃ H ₂ ) and its conjugate base group (hereinafter referred to as phosphonateoxy group), dialkyl phosphonooxy group (—OPO ₃ (alkyl)) _2), diaryl phosphonooxy group (-OPO ₃ (aryl) _2), alkylaryl phosphonooxy group (-OP ₃ (alkyl) (aryl)), monoalkyl phosphonooxy group (-OPO ₃ H (alkyl)) and its conjugated base group (hereinafter referred to as alkyl phosphonophenyl group), monoaryl phosphonooxy group (-OPO ₃ H (aryl)) and its conjugate base group (hereinafter referred to as arylphosphonatooxy group), cyano group, nitro group, aryl group, heteroaryl group, alkenyl group, and alkynyl group.

  Specific examples of the alkyl group in these substituents include the above-described alkyl groups, and specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, a tolyl group, a xylyl group, a mesityl group, and a cumenyl group. , Chlorophenyl group, bromophenyl group, chloromethylphenyl group, hydroxyphenyl group, methoxyphenyl group, ethoxyphenyl group, phenoxyphenyl group, acetoxyphenyl group, benzoyloxyphenyl group, methylthiophenyl group, phenylthiophenyl group, methylamino Phenyl group, dimethylaminophenyl group, acetylaminophenyl group, carboxyphenyl group, methoxycarbonylphenyl group, ethoxyphenylcarbonyl group, phenoxycarbonylphenyl group, N-phenylcarbamoylphenyl group, phenyl group Cyanophenyl group, sulfophenyl group, sulfonatophenyl group, phosphonophenyl phenyl group, phosphonophenyl phenyl group and the like.

As the preferred heteroaryl group as R ₁ , R ₂ and R ₃ , a monocyclic or polycyclic aromatic ring containing at least one of nitrogen, oxygen and sulfur atoms is used, and examples of particularly preferred heteroaryl groups are as follows. Is, for example, thiophene, thiathrene, furan, pyran, isobenzofuran, chromene, xanthene, phenoxazine, pyrrole, pyrazole, isothiazole, isoxazole, pyrazine, pyrimidine, pyridazine, indolizine, isoindolizine, indolizine, indazole, indazole, Purine, quinolidine, isoquinoline, phthalazine, naphthyridine, quinazoline, sinoline, pteridine, carbazole, carboline, phenanthrine, acridine, perimidine, phenanthrolin, phthalazine, phenalazine, phenoxazine, flaza And phenoxazine and the like, and these may be further benzo-fused or may have a substituent.

Examples of preferable alkenyl groups as R ₁ , R ₂ and R ₃ include vinyl group, 1-propenyl group, 1-butenyl group, cinnamyl group, 2-chloro-1-ethenyl group and the like, and alkynyl Examples of the group include ethynyl group, 1-propynyl group, 1-butynyl group, trimethylsilylethynyl group and the like. Examples of G ₁ in the acyl group (G ₁ CO—) include a hydrogen atom, and the above alkyl group and aryl group. Of these substituents, halogen atoms (—F, —Br, —Cl, —I), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, N-alkylamino groups, N, N— Dialkylamino group, acyloxy group, N-alkylcarbamoyloxy group, N-arylcarbamoyloxy group, acylamino group, formyl group, acyl group, carboxyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, N-alkylcarbamoyl group N, N-dialkylcarbamoyl group, N-arylcarbamoyl group, N-alkyl-N-arylcarbamoyl group, sulfo group, sulfonate group, sulfamoyl group, N-alkylsulfamoyl group, N, N-dialkylsulfamoyl group Group, N-arylsulfa Yl group, N-alkyl-N-arylsulfamoyl group, phosphono group, phosphonate group, dialkyl phosphono group, diaryl phosphono group, monoalkyl phosphono group, alkyl phosphonate group, monoaryl phosphono group, aryl phosphine group Examples include an onato group, a phosphonooxy group, a phosphonateoxy group, an aryl group, and an alkenyl group.

  On the other hand, examples of the alkylene group in the substituted alkyl group include divalent organic residues obtained by removing any one of the hydrogen atoms on the alkyl group having 1 to 20 carbon atoms. Can include linear alkylene groups having 1 to 12 carbon atoms, branched chains having 3 to 12 carbon atoms, and cyclic alkylene groups having 5 to 10 carbon atoms.

Specific examples of preferred substituted alkyl groups as R ₁ , R ₂ and R ₃ obtained by combining the substituent with an alkylene group include chloromethyl, bromomethyl, 2-chloroethyl, trifluoromethyl, methoxy Methyl group, methoxyethoxyethyl group, allyloxymethyl group, phenoxymethyl group, methylthiomethyl group, tolylthiomethyl group, ethylaminoethyl group, diethylaminopropyl group, morpholinopropyl group, acetyloxymethyl group, benzoyloxymethyl group, N -Cyclohexylcarbamoyloxyethyl group, N-phenylcarbamoyloxyethyl group, acetylaminoethyl group, N-methylbenzoylaminopropyl group, 2-oxoethyl group, 2-oxopropyl group, carboxypropyl group, methoxycarbo Nylethyl group, allyloxycarbonylbutyl group, chlorophenoxycarbonylmethyl group, carbamoylmethyl group, N-methylcarbamoylethyl group, N, N-dipropylcarbamoylmethyl group, N- (methoxyphenyl) carbamoylethyl group, N-methyl- N- (sulfophenyl) carbamoylmethyl group, sulfobutyl group, sulfonatobutyl group, sulfamoylbutyl group, N-ethylsulfamoylmethyl group, N, N-dipropylsulfamoylpropyl group, N-tolylsulfamoylpropyl group N-methyl-N- (phosphonophenyl) sulfamoyloctyl group, phosphonobutyl group, phosphonatohexyl group, diethylphosphonobutyl group, diphenylphosphonopropyl group, methylphosphonobutyl group, methylphosphonatobu Group, tolylphosphonohexyl group, tolylphosphonatohexyl group, phosphonooxypropyl group, phosphonateoxybutyl group, benzyl group, phenethyl group, α-methylbenzyl group, 1-methyl-1-phenylethyl group, p -Methylbenzyl group, cinnamyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallyl group, 2-methylpropenylmethyl group, 2-propynyl group, 2-butynyl group, 3-butynyl group, etc. Can be mentioned.

Specific examples of preferred aryl groups as R ₁ , R ₂ and R ₃ include those in which 1 to 3 benzene rings form a condensed ring, and those in which a benzene ring and a 5-membered unsaturated ring form a condensed ring. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, an indenyl group, an acenaphthenyl group, and a fluorenyl group, and among these, a phenyl group and a naphthyl group are more preferable. .

Specific examples of preferred substituted aryl groups as R ₁ , R ₂ and R ₃ include those having a monovalent non-metallic atomic group excluding a hydrogen atom as a substituent on the ring-forming carbon atom of the aryl group. It is done. Examples of preferred substituents include the aforementioned alkyl groups, substituted alkyl groups, and those previously shown as substituents in the substituted alkyl group. Preferred examples of such a substituted aryl group include biphenyl group, tolyl group, xylyl group, mesityl group, cumenyl group, chlorophenyl group, bromophenyl group, fluorophenyl group, chloromethylphenyl group, trifluoromethylphenyl group. Hydroxyphenyl group, methoxyphenyl group, methoxyethoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, methylthiophenyl group, tolylthiophenyl group, ethylaminophenyl group, diethylaminophenyl group, morpholinophenyl group, acetyloxyphenyl group, Benzoyloxyphenyl group, N-cyclohexylcarbamoyloxyphenyl group, N-phenylcarbamoyloxyphenyl group, acetylaminophenyl group, N-methylbenzoylaminophenyl group, carbo Cyphenyl group, methoxycarbonylphenyl group, allyloxycarbonylphenyl group, chlorophenoxycarbonylphenyl group, carbamoylphenyl group, N-methylcarbamoylphenyl group, N, N-dipropylcarbamoylphenyl group, N- (methoxyphenyl) carbamoylphenyl group N-methyl-N- (sulfophenyl) carbamoylphenyl group, sulfophenyl group, sulfonatophenyl group, sulfamoylphenyl group, N-ethylsulfamoylphenyl group, N, N-dipropylsulfamoylphenyl group, N-tolylsulfamoylphenyl group, N-methyl-N- (phosphonophenyl) sulfamoylphenyl group, phosphonophenyl group, phosphonatophenyl group, diethylphosphonophenyl group, diphenylphosphono Enyl group, methylphosphonophenyl group, methylphosphonatophenyl group, tolylphosphonophenyl group, tolylphosphonatophenyl group, allyl group, 1-propenylmethyl group, 2-butenyl group, 2-methylallylphenyl group, 2- Examples thereof include a methylpropenylphenyl group, a 2-propynylphenyl group, a 2-butynylphenyl group, and a 3-butynylphenyl group.

Next, A in the general formula (IX) will be described. A represents an aromatic ring or a hetero ring which may have a substituent. Specific examples of the aromatic ring or hetero ring which may have a substituent include R ₁ and R in the general formula (IX) similar to those described in ₂ and R ₃ can be exemplified.

The sensitizing dye represented by the general formula (IX) of the present invention includes an acidic nucleus as shown above, an acidic nucleus having an active methylene group, a substituted or unsubstituted aromatic ring or heterocyclic ring. These can be synthesized by referring to Japanese Patent Publication No. 59-28329.

  Preferred specific examples (D1) to (D76) of the compound represented by formula (IX) are shown below. In addition, an isomer with a double bond connecting an acidic nucleus and a basic nucleus is not limited to either isomer.

Details of the usage such as which structure of these sensitizing dyes are used, whether they are used alone or in combination of two or more, and how much is added, can be appropriately set according to the performance design of the final photosensitive material. .
For example, the compatibility with the photosensitive composition layer can be enhanced by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film physical properties of the photosensitive layer when used in a lithographic printing plate precursor. It is. The photosensitivity and resolution of the photosensitive layer and the physical properties of the exposed film are greatly affected by the absorbance at the light source wavelength, and thus the addition amount of the sensitizing dye is appropriately selected in consideration of these.

  However, for example, for the purpose of curing a thick film having a thickness of 5 μm or more, the degree of curing may be increased by lower absorbance. When used as a lithographic printing plate used in a relatively thin film thickness, the addition amount of the sensitizing dye is such that the absorbance of the photosensitive layer of the present invention is in the range of 0.1 to 1.5, preferably from 0.25. It is preferable to set so as to be in the range of 1. Usually, it is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, and most preferably 0.2 to 10% by mass with respect to the total solid content of the photosensitive layer.

(B) Polymerization initiator The polymerization initiator used in the present invention includes trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, and organic boron compounds. , Disulfone compounds, oxime ester compounds, and onium salt compounds. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable.

  Examples of the hexaarylbiimidazole polymerization initiator include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, for example, 2,2′-bis (o-chlorophenyl) -4,4 ′. , 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p- Dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5 5 ' Tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

  The trihalomethyl compound is preferably trihalomethyl-s-triazine, 2,4,6-tris (trichloromethyl) -s-triazine, 2-methoxy-4,6-bis (trichloromethyl) -s-triazine, 2- Trimethyl compounds described in JP-A-58-29803 such as amino-4,6-bis (trichloromethyl) -s-triazine, 2- (P-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine and the like. Examples thereof include s-triazine derivatives having a halogen-substituted methyl group.

  Examples of the onium salt include onium salts represented by the following general formula (III).

In general formula (III), R ¹¹ , R ¹² and R ¹³ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferable substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms.
Z ⁻ represents a counter ion selected from the group consisting of halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, carboxylate ion, and sulfonate ion, preferably perchlorate ion, hexa Fluorophosphate ions, carboxylate ions, and aryl sulfonate ions.

As the titanocene compound, for example, known compounds described in JP-A Nos. 59-152396 and 61-151197 can be appropriately selected and used.
Specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5, 6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2, 4,6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,4-difluoro Phen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2, 3, 5, 6 Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophen-1-yl, bis (cyclopentadienyl) -bis [2,6-difluoro-3- ( Pyr-1-yl) phenyl] titanium and the like.

  Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone and other benzophenone derivatives, 2,2-dimethoxy- 2-phenylacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, α-hydroxy-2-methylphenylpropanone, 1-hydroxy-1-methylethyl- (p-isopropylphenyl) ketone, 1- Hydroxy-1- (p-dodecylphenyl) ketone, 2-methyl- (4 ′-(methylthio) phenyl) -2-morpholino-1-propanone, 1,1,1-trichloromethyl- (p-butylphenyl) Acetophenone derivatives such as ketones, thioxanthone derivatives such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, p- Examples thereof include benzoic acid ester derivatives such as ethyl dimethylaminobenzoate and ethyl p-diethylaminobenzoate.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A.

The polymerization initiator in the present invention is suitably used alone or in combination of two or more.
The amount of the polymerization initiator used in the photosensitive layer in the present invention is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the photosensitive layer. More preferably, it is 1.0 mass%-10 mass%.

(C) Polymerizable compound The polymerizable compound used in the photosensitive layer in the invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and preferably has at least one terminal ethylenically unsaturated bond. Is selected from compounds having two or more. Such a compound group is widely known in the industrial field, and these can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of monomers of esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, isocyanuric acid ethylene oxide (EO) Examples include modified triacrylates and polyester acrylate oligomers.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  Further, urethane-based addition polymerizable compounds produced by using an addition reaction of isocyanate and hydroxyl group are also suitable. Specific examples thereof include, for example, one molecule described in JP-B-48-41708. A vinyl urethane compound containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxyl group represented by the following general formula (B) to a polyisocyanate compound having two or more isocyanate groups Etc.

_{CH 2 = C (R 4)} COOCH 2 CH (R 5) OH (B)
(However, R ₄ and R ₅ represent H or CH _3. )

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount, etc. can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. Further, different functional numbers and different polymerizable groups (for example, acrylic acid ester, methacrylic acid ester, styrenic compound, vinyl ether type). A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the selection and use method of the polymerizable compound is an important factor for the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.) For example, the compatibility may be improved by using a low-purity compound or using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass, based on the total solid content of the photosensitive layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

(D) Binder polymer In this invention, a binder polymer is contained in the photosensitive layer.
As the binder polymer, an organic polymer that is soluble or swellable in alkaline water is used because it must be dissolved in an alkaline developer as well as a film-forming agent for the photosensitive layer. That is, it is a polymer that is soluble or swellable in alkaline water, and thus can be removed by applying pressure, such as a brush, as necessary by alkaline development.

  The binder polymer used in the present invention is a binder polymer having a structural unit represented by the following formulas (1) to (3).

In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ₃ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyl group, a halogen atom, 1 represents a substituted alkyl group having 1 to 6 carbon atoms substituted with an amino group, a methoxy group or a carboxyl group, and X represents a functional group selected from —COOH, —CO—W ₁ —L ₁ —COOH and —SO ₃ H. W ₁ represents an oxygen atom, a sulfur atom or a —NH— group, L 1 represents a divalent organic group, Y represents a —CO—O—CH ₂ —CH═CH ₂ group, —CO—W ₂ —. L ₂ —O—CO—CR ₄ ═CH ₂ represents a group, W ₂ represents an oxygen atom, sulfur atom or —NH— group, L ₂ represents a divalent organic group, and R ₄ represents a hydrogen atom or carbon. 1 represents an alkyl group of 1 to 6, and W ₃ represents an oxygen atom, a sulfur atom or —NH— represents a group, and R ₅ represents an alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms, or a group having an aromatic ring having 6 to 20 carbon atoms.

Specific examples of the structural units represented by the formulas (1) to (3) are described below, but are not limited thereto.
Specific examples of the repeating unit represented by the formula (1) include the structures shown below.

  Specific examples of the repeating unit represented by the formula (2) include the structures shown below.

Specific examples of the repeating unit represented by the formula (3) include methyl (meth) acrylate, ethyl (meth) acrylate, isobutyl (meth) acrylate, normal butyl (meth) acrylate, isopropyl (meth) acrylate, cyclohexyl (meth) ) Acrylates, n-hexyl (meth) acrylates, adamantyl (meth) acrylates, benzyl (meth) acrylates, phenethyl (meth) acrylates, and other alkyl or aryl (meth) acrylates, and (meth) acrylates represented by the following formula: Can be mentioned.
In the following, preferred substituents for R include methyl group, ethyl group, isopropyl group, n-butyl group, t-butyl group, cyclohexyl group, phenethyl group, benzyl group, and n-hexyl group.

In order to maintain the developability of the photopolymerization type photosensitive layer, the binder polymer used preferably has an appropriate molecular weight and acid value, and has a mass average molecular weight of 5,000 to 300,000 and an acid value of 0.5 to 200. The high molecular weight polymer is particularly preferable. Here, the acid value refers to the number of mg of potassium hydroxide necessary to neutralize free fatty acids contained in 1 g of a sample. The acid value is more preferably 5.0 to 180, and particularly preferably 10 to 150.
The ratio of the total amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (3) to the structural unit having an ethylenically unsaturated double bond represented by the formula (2) is: The mass ratio is preferably 0.1 to 3.0, more preferably 0.1 to 2.0, and most preferably 0.1 to 1.0.
As long as the combination satisfies the above molecular weight, acid value, and double bond amount, the mixing ratio of the structural units represented by the formulas (1), (2), and (3) may be any combination. good. If it is the range which satisfies these, you may further add structural units other than the structural unit represented by Formula (1)-(3).

  These binder polymers can be contained in an arbitrary amount in the photosensitive layer, but are generally 90% by mass or less, preferably 10 to 90% by mass in terms of formed image strength and the like. More preferably, it is 30-80 mass%.

In the present invention, a polymer that is soluble or swellable in alkaline water other than the above-mentioned polymer can be used, or the above-mentioned polymer and another polymer can be mixed and used.
Examples of other organic polymer polymers that are polymers soluble or swellable in alkaline water include various polymers. When water development is desired, for example, water-soluble organic polymer polymers are used. Examples of such an organic polymer include addition polymers having a carboxylic acid group in the side chain, such as JP 59-44615, JP-B 54-34327, JP-B 58-12577, JP-B 54-. No. 25957, JP 54-92723, JP 59-53836, JP 59-71048, ie, methacrylic acid copolymer, acrylic acid copolymer, itacon Cyclic acid anhydrides for acid copolymers, crotonic acid copolymers, maleic acid copolymers, partially esterified maleic acid copolymers, acidic cellulose derivatives having a carboxylic acid group in the side chain, and addition polymers having a hydroxyl group Products, polyvinyl pyrrolidone, polyethylene oxide, and alcohol-soluble polyamide or 2,2-bis- (4-hydride) that can increase the strength of the cured film Kishifeniru) - and a polyether of propane and epichlorohydrin.
Furthermore, JP-B-7-120040, JP-B-7-120041, JP-B-7-120042, JP-B-8-12424, JP-A-63-287944, JP-A-63-287947, JP-A-1 Polyurethane resins described in JP-A Nos. -271741 and JP-A No. 11-352691 can also be used in the application of the present invention.

  In order to maintain the developability of the photosensitive layer, the binder polymer used preferably has an appropriate molecular weight and acid value, and is a high molecular weight polymer having a mass average molecular weight of 5,000 to 300,000 and an acid value of 20 to 200. Is particularly preferred.

(E) Mercapto compound The photosensitive layer of the present invention preferably contains a mercapto compound having a mercapto group. (E) Mercapto compounds are effective in improving sensitivity.

  In the present invention, it is preferable to use at least one compound selected from 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole, and a mercapto compound represented by the following formula (4).

In the formula, R ₆ represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms, or a group having an aromatic ring having 6 to 20 carbon atoms. X represents an oxygen atom, a sulfur atom or —N (R ₇ ) —, R ₇ represents a linear alkyl group having 1 to 18 carbon atoms or a branched alkyl group, and an alkyl group having an alicyclic structure having 5 to 20 carbon atoms. Or the group which has a C6-C20 aromatic ring is shown.

  Preferable examples of the compound represented by the formula (4) include the following compounds.

The mercapto compound represented by the formula (4) can be synthesized by a known method such as the method described in JP-A-5-124991. A commercially available product may also be used.
The addition amount of the mercapto compound is generally 0.5 to 20% by mass, preferably 1 to 15% by mass, and more preferably 1 to 10% by mass with respect to all components constituting the photosensitive layer.

(F) Other additives It is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization in the photosensitive layer during the production or storage of the lithographic printing plate precursor. Suitable thermal polymerization inhibitors include haloid quinone, 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-tert-butylphenol), N-nitrosophenylhydroxylamine primary cerium salt, N-nitrosophenylhydroxylamine aluminum salt and the like.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01% by mass to about 5% by mass with respect to the total solid content constituting the photosensitive layer.
If necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide is added to the photosensitive layer of the present invention in order to prevent polymerization inhibition due to oxygen, and the photosensitive layer is subjected to drying after coating. The surface may be unevenly distributed. The addition amount of the higher fatty acid derivative or the like is preferably about 0.5% by mass to about 10% by mass with respect to the total solid content constituting the photosensitive layer.
Further, for the purpose of coloring the photosensitive layer, a colorant may be added. Examples of the colorant include phthalocyanine pigments (CIPigment Blue 15: 3, 15: 4, 15: 6, etc.), azo pigments, pigments such as carbon black and titanium oxide, ethyl violet, crystal violet, azo dye, anthraquinone. There are dyes and cyanine dyes. The addition amount of the colorant is preferably about 0.5% by mass to about 20% by mass of the total solid content of the photosensitive layer. In addition, in order to improve the physical properties of the cured film, an additive such as an inorganic filler or a plasticizer such as dioctyl phthalate, dimethyl phthalate, or tricresyl phosphate may be added. These addition amounts are preferably 10% by mass or less based on the total solid content of the photosensitive layer.

[Formation of photosensitive layer]
When coating the photosensitive layer, the above components are dissolved in a solvent to prepare a coating solution. Solvents used here include acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, ethylene dichlorite, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether. , Acetylacetone, cyclohexanone, diacetone alcohol, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether acetate, 3-methoxypropanol, methoxymethoxyethanol, diethylene glycol monomethyl ether, di Ethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate-3-methoxypropyl acetate, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, methyl lactate, lactic acid There are organic solvents such as ethyl. A solvent can be used individually or in mixture.
The density | concentration of the solid content in a coating solution is 1-50 mass% normally.

  In addition, a surfactant can be added to improve the coating surface quality.

The coverage of the photosensitive layer in the weight after drying is generally about 0.1 to about 10 g / m ^2, preferably from 0.3 to 5 g / m ^2, more preferably 0.5 to 3 g / m ^2.

[Protective layer]
The lithographic printing plate precursor according to the invention is provided with a protective layer containing a water-soluble resin. The protective layer also functions as an oxygen blocking layer that blocks diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer used in the present invention preferably has an oxygen permeability A at 25 ° C. and 1 atm of 1.0 ≦ A ≦ 20 (mL / m ² · day). When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably in the range of 1.5 ≦ A ≦ 12 (mL / m ² · day), more preferably 2.0 ≦ A ≦ 8.0 (mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and in the development step after exposure. It is desirable that it can be easily removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, or an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of the polyvinyl alcohol include those having a hydrolysis rate of 71 to 100 mol% and a polymerization repeating unit of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the thicker the film thickness, the higher the oxygen barrier property, which is advantageous in terms of sensitivity. The molecular weight of the polymer compound such as polyvinyl alcohol (PVA) can be in the range of 2000 to 10 million, preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the polymer compound to give flexibility. Also, sodium alkyl sulfate, sodium alkyl sulfonate Anionic surfactants such as: amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers are added to the polymer compound by several mass% be able to. The thickness of the protective layer is suitably 0.5 to 5 μm, particularly 1 to 3 μm.

  In addition, adhesion to the photosensitive layer and scratch resistance are extremely important in handling the lithographic printing plate precursor. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

The coating amount of the protective layer is a dry weight, generally 0.1 to 10 g / m ^2, preferably from 0.5 to 5 g / m ^2.

[Support]
The support used for the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. In the present invention, a pure aluminum plate is preferable, but completely pure aluminum is difficult to manufacture in terms of refining technology, and therefore may contain a slightly different element. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to roughening the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used and cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  After the anodizing treatment, the surface of the aluminum plate is subjected to a hydrophilic treatment as necessary. The hydrophilization treatment is described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in each specification of No.272.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

[Middle layer]
The intermediate layer in the present invention contains (i) a metal oxide obtained by hydrolysis and polycondensation of an organometallic compound or an inorganic metal compound, and in addition, (ii) colloidal silica sol and (iii) A form containing a molecular compound is preferred. The intermediate layer may further contain a plasticizer.

  Examples of the metal oxide used for the intermediate layer include silica (silicon oxide), titanium oxide, boron oxide, aluminum oxide, zirconium oxide, and composites thereof. The metal oxide in the intermediate layer used in the present invention is a so-called sol obtained by hydrolyzing an organic metal compound or an inorganic metal compound in water and an organic solvent with a catalyst such as an acid or alkali, and causing a condensation polymerization reaction. -It obtains by apply | coating a gel reaction liquid to the back surface of a support body, and drying. Examples of the organic metal compound or inorganic metal compound used here include metal alkoxide, metal acetylacetonate, metal acetate, metal oxalate, metal nitrate, metal sulfate, metal carbonate, metal oxychloride, and metal chloride. And condensates obtained by partially hydrolyzing them to form oligomers.

The metal alkoxide is represented by a general formula of M (OR) _n (M is a metal element, R is an alkyl group, and n is an oxidation number of the metal element). For example, Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ , Al (OCH ₃ ) ₃ , Al (OC _2). H ₅ ) ₃ , Al (OC ₃ H ₇ ) ₃ , Al (OC ₄ H ₉ ) ₃ , B (OCH ₃ ) ₃ , B (OC ₂ H ₅ ) ₃ , B (OC ₃ H ₇ ) ₃ , B ( _{OC 4 H 9) 3, Ti} (OCH 3) 4, Ti (OC 2 H 5) 4, Ti (OC 3 H 7) 4, Ti (OC 4 H 9) 4, Zr (OCH 3) 4, Zr ( OC ₂ H ₅ ) ₄ , Zr (OC ₃ H ₇ ) ₄ , Zr (OC ₄ H ₉ ) _{4 and the} like are used. Other examples include alkoxides such as Ge, Li, Na, Fe, Ga, Mg, P, Sb, Sn, Ta, and V. Further, mono-substituted silicon such as CH ₃ Si (OCH ₃ ) ₃ , C ₂ H ₅ Si (OCH ₃ ) ₃ , CH ₃ Si (OC ₂ H ₅ ) ₃ , C ₂ H ₅ Si (OC ₂ H ₅ ) ₃ Alkoxides are also used. Examples of the metal acetylacetonate include Al (COCH ₂ COCH ₃ ) ₃ and Ti (COCH ₂ COCH ₃ ) ₄ . Examples of metal oxalates include K ₂ TiO (C ₂ O ₄ ) ₂ , and examples of metal nitrates include Al (NO ₃ ) ₃ and ZrO (NO ₃ ) ₂ .2H ₂ O. Examples of metal sulfates include Al ₂ (SO ₄ ) ₃ , (NH ₄ ) Al (SO ₄ ) ₂ , KAl (SO ₄ ) ₂ , NaAl (SO ₄ ) ₂ , and examples of metal oxychlorides include Si _2. Examples of OCl ₆ , ZrOCl ₂ , and chloride include AlCl ₃ , SiCl ₄ , ZrCl ₂ , and TiCl ₄ .

  These organic metal compounds or inorganic metal compounds can be used alone or in combination of two or more.

Moreover, in this invention, it is preferable that an intermediate | middle layer contains the organosilicone compound which has a functional group which can raise | generate addition polymerization by a radical. By including the organosilicone compound, the balance between the adhesion between the intermediate layer and the photosensitive layer and the generation of debris during development processing is further improved.
When the functional group capable of causing addition polymerization by radicals is represented as R ₁ , the organosilicone compound has the following formula (1):
R ₁ Si (OR ₂ ) ₃ (1)
(Wherein, —OR ₂ is a hydrolyzable alkoxy group or —OCOCH ₃ group).

R ₁ is not particularly limited. For example, CH ₂ = CHCOO- (CH ₂ ) _3- , CH ₂ = C (CH ₃ ) COO- (CH ₂ ) _3- , CH ₂ = CH-C (= CH ₂ )-, CH ₂ = CH-S0 ₂ NH- (CH ₂ ) _3- ,

CH ₂ = CH-, HC≡C-, CH ₃ C≡C-,

_{CH 2 = CHCH 2 O-, CH} 2 = CHCOO- (CH 2) 4 -, CH 2 = C (CH 3) COO- (CH 2) 4 -, CH 2 = C (CH 3) COO- (CH 2 ) _5- , CH ₂ = CHCH _2- , HO-CH ₂ -C≡C-, CH ₃ CH ₂ CO-C≡C-, CH ₂ = CHS- (CCH ₂ ) _3- , CH ₂ = CHCH ₂ O -(CH ₂ ) ₂ -SCH _2- , CH ₂ = CHCH ₂ S- (CH ₂ ) ₃ -S-, (CH ₃ ) ₃ -CCO-C≡C-, CH ₂ = CHCH ₂ NH- (CH ₂ ) _3- , (CH ₂ = CH) ₂ -N- (CH ₂ ) ₂ -SCH _2- ,

Etc.

Specific examples of the organic silicone compound represented by the above formula (1) used in the present invention include the following.
CH ₂ = CH-Si (OCOCH ₃ ) ₃ , CH ₂ = CH-Si (OC ₂ H ₅ ) ₃ , CH ₂ = CHSi (OCH ₃ ) ₃ , CH ₂ = CHCH ₂ Si (OC ₂ H ₅ ) ₃ , CH ₂
= CHCH ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₂ = CHCOO- (CH ₂ ) ₃ -Si (OCH ₃ ) ₃ , CH ₂ = CHCOO- (CH ₂ ) ₃ -Si (OC ₂ H ₅ ) ₃
, CH ₂ = C (CH ₃ ) COO- (CH ₂ ) ₃ -Si (OCH ₃ ) ₃ , CH ₂ = C (CH ₃ ) COO- (CH ₂ ) ₃ -Si (OC ₂ H ₅ ) ₃ , CH ₂ = C (CH ₃ ) COO- (CH ₂ ) ₄ -Si (OCH ₃ ) ₃ , CH ₂ = C (CH ₃ ) COO- (CH ₂ ) ₅ -Si (OCH ₃ ) ₃ , CH ₂ = CHCOO- (CH ₂ ) ₄ -Si (OCH ₃ ) ₃ ,

CH ₂ = CH-SO ₂ NH- (CH ₂ ) ₃ -Si (OCH ₃ ) ₃ ,

HC≡C-Si (OC ₂ H ₅ ) ₃ , CH ₃ C≡C-Si (OC ₂ H ₅ ) ₃ ,

CH ₂ = CHCH ₂ O-Si (OCH ₃ ) ₃ , (CH ₂ = CHCH ₂ O) ₄ Si, HO-CH ₂ -C≡C-Si (OC ₂ H ₅ ) ₃ , CH ₃ CH ₂ CO-C ≡C-Si (OC ₂ H ₅ ) ₃ , CH ₂ = CHS- (CH ₂ ) ₃ -Si (OCH ₃ ) ₃ , CH ₂ = CHCH ₂ O- (CH ₂ ) ₂ -SCH ₂ -Si (OCH ₃ ) ₃ , CH ₂ = CHCH ₂ S- (CH ₂ ) ₃ -S-Si (OCH ₃ ) ₃ , (CH ₃ ) ₃ CCO-C ≡ C-Si (OC ₂ H ₅ ) ₃ , (CH ₂ = CH ) ₂ N- (CH ₂ ) ₂ -SCH ₂ -Si (OCH ₃ ) ₃ ,

_{CH 3 COCH = C (CH 3} ) -O-Si (OCH 3) 3.

  When the metal alkoxide is used, the molar ratio of the metal alkoxide to the organosilicone compound is suitably 0.05 to 200, preferably 0.2 to 100, more preferably 1 as the ratio with the organosilicone compound. ~ 40. At this ratio, the effect of reducing the generation of debris during development processing is further enhanced. In addition, adhesion to the photosensitive layer is increased, and printing durability and halftone dot reproducibility are improved. Examples of means for obtaining the ratio include sol-gel reaction control (leaving organicity), adjustment of the mixing ratio of metal alkoxide and organosilicone compound, adjustment by additives (organic polymer, plasticizer), and the like.

  On the other hand, organic and inorganic acids and alkalis are used as the catalyst. Examples include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, hydrofluoric acid, phosphoric acid, phosphorous acid and other inorganic acids, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid , Fluoroacetic acid, bromoacetic acid, methoxyacetic acid, oxaloacetic acid, citric acid, oxalic acid, succinic acid, malic acid, tartaric acid, fumaric acid, maleic acid, malonic acid, ascorbic acid, benzoic acid, 3,4-dimethoxybenzoic acid Substituted benzoic acid, phenoxyacetic acid, phthalic acid, picric acid, nicotinic acid, picolinic acid, pyrazine, pyrazole, dipicolinic acid, adipic acid, p-toluic acid, terephthalic acid, 1,4-cyclohexene-2,2-dicarboxylic acid Acids, erucic acid, lauric acid, n-undecanoic acid, organic acids such as ascorbic acid, alkali metals and alkaline earths Genus hydroxide, ammonia, ethanolamine, diethanolamine, and alkali such as triethanolamine. In addition, sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, and phosphate esters, such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl acid, phenylphosphonic acid Organic acids such as phenylphosphinic acid, phenyl phosphate, and diphenyl phosphate can also be used. These catalysts can be used alone or in combination of two or more. The catalyst is preferably from 0.001 to 10% by mass, more preferably from 0.05 to 5% by mass, based on the starting metal compound. If the amount of the catalyst is less than this range, the start of the sol-gel reaction is delayed, and if it is more than this range, the reaction proceeds rapidly and often gels immediately, so that the coating operation may not be performed stably. is there.

In order to initiate the sol-gel reaction, an appropriate amount of water is further required, and the preferred amount of addition is preferably 0.05 to 50 times the amount of water required to completely hydrolyze the starting metal compound. More preferably, it is 0.5 to 30 times mol. If the amount of water is less than this range, the hydrolysis is difficult to proceed, and if it is more than this range, the reaction is difficult to proceed because the raw material is diluted. A solvent is further added to the sol-gel reaction solution. Any solvent may be used as long as it dissolves the starting metal compound and dissolves or disperses the sol-gel particles produced by the reaction, such as lower alcohols such as methanol, ethanol, propanol, and butanol, acetone, methyl ethyl ketone, diethyl ketone, and the like. Ketones are used. In addition, mono- or dialkyl ethers and acetates of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol can be used for the purpose of improving the coating surface quality of the intermediate layer. Of these solvents, lower alcohols that are miscible with water are preferred. The sol-gel reaction solution is prepared with a solvent at a concentration suitable for coating. However, if the total amount of the solvent is added to the reaction solution from the beginning, the raw material is diluted, making it difficult for the hydrolysis reaction to proceed.
Therefore, a method of adding a part of the solvent to the sol-gel reaction solution and adding the remaining solvent when the reaction proceeds is preferable.

The sol-gel reaction proceeds by mixing a metal oxide raw material, water, a solvent, and a catalyst. The progress of the reaction depends on the type, composition ratio, temperature and time of the reaction, and affects the film quality after film formation. In particular, since the influence of the reaction temperature is large, it is preferable to control the temperature during the reaction. In addition to the above-mentioned essential components, a compound containing a hydroxyl group, an amino group or an active hydrogen in the molecule may be added to the sol-gel reaction solution in order to appropriately adjust the sol-gel reaction. These compounds include polyethylene glycol, polypropylene glycol, their block copolymers, and their monoalkyl ethers or monoalkyl aryl ethers, various phenols such as phenol and cresol, copolymerization with polyvinyl alcohol and other vinyl monomers. Examples thereof include acids having hydroxyl groups such as coalesce, malic acid and tartaric acid, aliphatic and aromatic amines, formaldehyde and dimethylformaldehyde. Furthermore, an organic polymer compound can be added in order to improve and solubilize the affinity of the coating solution dried product to the organic solvent.

  Examples of (iii) organic polymer compounds in the intermediate layer include polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl phenol, polyvinyl halogenated phenol, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyamide, polyurethane, polyurea, polyimide. Polycarbonate, epoxy resin, phenol novolac, or resole phenols and aldehyde or ketone condensation resin, polyvinylidene chloride, polystyrene, silicone resin, active methylene, phenolic hydroxyl group, sulfonamide group, carboxyl group and other alkali-soluble groups Examples thereof include acrylic copolymers and binary or ternary or higher copolymer resins thereof. Particularly preferred compounds are specifically phenol novolac resins or resole resins, such as phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol-modified xylene, tert-butylphenol, octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl, p-Cl), bromophenol (m-Br, p-Br), salicylic acid, furo Examples thereof include novolak resins and resole resins condensed with formaldehyde such as loglucinol, and further condensed resins of the above phenolic compounds and acetone.

Examples of other suitable polymer compounds include copolymers having a molecular weight of usually 10,000 to 200,000 having monomers shown in the following (1) to (12) as structural units.
(1) Acrylamides, methacrylamides, acrylic esters, methacrylic esters and hydroxystyrenes having an aromatic hydroxyl group, such as N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide O-, m- and p-hydroxystyrene, o-, m- and p-hydroxyphenyl acrylate or methacrylate, (2) acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl Acrylate or 2-hydroxyethyl methacrylate, (3) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, acrylate acrylate (Substituted) acrylic esters such as chill, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N-dimethylaminoethyl acrylate, (4) methyl methacrylate, methacryl Ethyl acetate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl (Substituted) methacrylate esters such as methacrylate and N-dimethylaminoethyl methacrylate,

(5) Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacryl Amide, N-hydroxyethylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N Acrylamide or methacrylate such as ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide (6) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether, (7) vinyl acetate, vinyl chloroacetate, vinyl butyrate, benzoic acid Vinyl esters such as vinyl; (8) styrenes such as styrene, methyl styrene and chloromethyl styrene; (9) vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone and phenyl vinyl ketone; and (10) ethylene. , Olefins such as propylene, isobutylene, butadiene, isoprene,

(11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc. (12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, Acrylamides such as N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) naphthyl] acrylamide, N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) Methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonyl) Echi ) Methacrylamides such as methacrylamide, and acrylic esters such as o-aminosulfonylphenyl acrylate, m-aminosulfonylphenyl acrylate, p-aminosulfonylphenyl acrylate, 1- (3-aminosulfonylphenylnaphthyl) acrylate, etc. Unsaturated sulfonamides such as methacrylic esters such as o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3-aminosulfonylphenylnaphthyl) methacrylate .

  These materials preferably have a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 60,000. Specifically, the addition amount is suitably 1 to 200% by mass relative to the starting metal compound. -100 mass% is preferable, and 5-50 mass% is especially most preferable. When the addition amount is larger than this, the original hydrophilicity of the sol-gel is deteriorated, and the stain resistance in printing is deteriorated.

  Furthermore, a plasticizer is added together with the above organic polymer compound in order to prevent a trouble with dust during manufacturing and coating due to the flaking of the dried liquid of the coating liquid and to obtain a stable coating surface quality. It is preferable. Examples of the plasticizer in the intermediate layer used in the present invention include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl. Glycolate, butyl phthalyl butyl glycolate, diisobutyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, diallyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate Rate, triethylene glycol dicaprylate, trioctyl trimellitate, dioctyl adipate, diocty Azelate, dibutyl sebacate, dioctyl sebacate, methyl acetylricinoleate, dimethyl malate, diethyl malate, dibutyl malate, dioctyl malate, dibutyl fumarate, dioctyl fumarate, adipic acid-propylene glycol ester, adipic acid-1 , 3 Butylene glycol ester, glycerol triacetate, glycerol tributyrate, cellulose acetate phthalate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, trischloroethyl phosphate, trisdichloropropyl phosphate, mono-2, 3-dichloropropyl-bis-2,3-dibromopropyl phosphate, triphenylphos Phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, diphenyl monoorthoxenyl phosphate, octyl diphenyl phosphate, triphenyl phosphite, trilauryl trithiophosphite, trischloroethyl phosphate, trilauryl phosphate, Trisnonyl phenyl phosphite, trisdinonyl phenyl phosphite, dibutyl hydrogen phosphite, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, octyl acid phosphate, dioctyl phosphate, isodecyl acid phosphate, monoisodecyl phosphate, tridecanol Acid phosphate is effective. Of these, those having a boiling point of 250 ° C. or higher at 760 mm Hg are particularly effective. Moreover, in order not to deteriorate the soiling property due to adhesion of the lipophilic substance at the time of plate making, those having a hydrophilicity as high as possible are preferable. The plasticizer is added in such a range that the intermediate layer is not sticky, but it is suitably 1 to 100% by weight, particularly preferably 5 to 30% by weight, based on the starting metal compound. When the addition amount is more than 100% by mass, the hydrophilicity of the non-image area after development is deteriorated, and the stain resistance in printing is deteriorated.

In the intermediate layer, (ii) colloidal silica sol may be added for the purpose of preventing hydrophilic deterioration. (Ii) Examples of colloidal silica sols include colloidal solutions of ultrafine particles of silicic acid using water, methanol, ethanol, isopropyl alcohol, butanol, xylene, dimethylformamide, or the like as a dispersion medium. A methanol dispersion medium is particularly preferred. The size of the dispersoid particles is preferably 1 to 100 μm, particularly preferably 10 to 50 μm. When the thickness is 100 μm or more, the uniformity of the coating film is deteriorated due to the unevenness of the surface.
Further, the content of silicic acid is preferably 5 to 80% by mass, and those having a hydrogen ion concentration that is not particularly in the neutral range (pH 6 to 8) are more preferable in terms of stability. Particularly preferred is the acidic range.
Silica sol can also be used in combination with other fine particles such as alumina sol or lithium silicate. These further improve the hardening properties of the sol-gel coating film. Specifically, the addition amount is 30% by mass or more and 300% by mass or less, more preferably 30% by mass to 200% by mass, and most preferably 50% by mass to 100% by mass with respect to the starting metal compound. . If the amount added is larger than this, the film properties deteriorate and it becomes difficult to apply uniformly. On the other hand, if the amount added is less than this, the effect of preventing hydrophilic deterioration cannot be obtained.

  Further, a surfactant may be added to the intermediate layer for the purpose of improving the coated surface state.

  Furthermore, higher fatty acids such as behenic acid, behenic acid amide, stearic acid, stearic acid amide, alkenyl succinic anhydride, higher fatty acid amide, wax, dimethylsiloxane, polyethylene powder, etc. are added to the intermediate layer as a lubricant. May be.

The coating amount of the intermediate layer is preferably in the range of 2~1000mg / m ^2, more preferably preferably 5 to 200 mg / m ^2, and most preferably 10 to 50 mg / m ^2. Various methods can be applied as a method of coating the intermediate layer on the support, but the most preferable method for securing the above coating amount is a method of coating and drying in a solution.

[Back coat]
After the surface treatment is applied to the support or the intermediate layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

[Plate making method]
Next, the plate making method of the lithographic printing plate precursor according to the invention will be described in detail. The above-described lithographic printing plate precursor is subjected to image exposure and then developed with an alkaline aqueous solution. Below, the developing solution used for the plate making method of this invention is demonstrated.

(Developer)
The developer used in the plate making method of the lithographic printing plate precursor according to the present invention is not particularly limited. For example, a developer containing an inorganic alkali salt and a surfactant and usually having a pH of 11.0 to 12.7. Preferably used.

  The inorganic alkali salt can be used as appropriate. For example, sodium hydroxide, potassium, ammonium, lithium, sodium silicate, potassium, ammonium, lithium, tribasic sodium phosphate, potassium, ammonium Inorganic alkaline agents such as sodium carbonate, potassium, ammonium, sodium hydrogen carbonate, potassium, ammonium, sodium borate, potassium, and ammonium. These may be used alone or in combination of two or more.

When silicate is used, developability can be achieved by adjusting the mixing ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali oxide M ₂ O (M represents an alkali metal or ammonium group). Can be easily adjusted. Among the alkaline aqueous solutions, those having a mixing ratio (SiO ₂ / M ₂ O: molar ratio) of the silicon oxide SiO ₂ and the alkali oxide M ₂ O of 0.5 to 3.0 are preferable, and 1.0 to 2 0.0 is preferred. The addition amount of SiO ₂ / M ₂ O is preferably 1 to 10% by mass, more preferably 3 to 8% by mass, and most preferably 4 to 7% by mass with respect to the mass of the alkaline aqueous solution. When the concentration is within the above range, developability and processing ability are not deteriorated, precipitation and crystals are not generated, gelation does not occur during neutralization at the time of waste liquid, and waste liquid processing is not hindered.

  In addition, an organic alkali agent may be supplementarily used for the purpose of delicate adjustment of the alkali concentration and supplementing the solubility of the photosensitive layer. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These alkali agents are used alone or in combination of two or more.

The surfactant can be used as appropriate. For example, nonionic surfactants having a polyoxyalkylene ether group, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate Nonionic surfactants such as sorbitan alkyl esters such as sorbitan distearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, and monoglyceride alkyl esters such as glycerol monostearate and glycerol monooleate; Alkyl benzene sulfonates such as sodium acetate, sodium butyl naphthalene sulfonate, sodium pentyl naphthalene sulfonate, sodium hexyl naphthalene sulfonate Anionic interfaces such as alkyl naphthalene sulfonates such as sodium, sodium octyl naphthalene sulfonate, alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, and sulfosuccinate esters such as sodium dilauryl sulfosuccinate Activators: Alkyl betaines such as lauryl betaine and stearyl betaine, amphoteric surfactants such as amino acids, and the like can be mentioned. Particularly preferred are nonionic surfactants having a polyoxyalkylene ether group.

  As the surfactant containing a polyoxyalkylene ether group, one having a structure of the following general formula (VIV) is preferably used.

R ₄₀ —O— (R ₄₁ —O) _pH (VI)

In the formula, R ₄₀ is an alkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, or a heteroaromatic ring group having 4 to 15 carbon atoms (in addition, the substituent is 1 to 20 carbon atoms). An alkylene group, a halogen atom such as Br, Cl, or I, an aromatic hydrocarbon group having 6 to 15 carbon atoms, an aralkyl group having 7 to 17 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkyl group having 2 to 20 carbon atoms An alkoxy-carbonyl group and an acyl group having 2 to 15 carbon atoms.), R ₄₁ represents an alkylene group having 1 to 100 carbon atoms, and p represents an integer of 1 to 100. Each of these groups may have a substituent, and examples of the substituent include an alkyl group having 1 to 20 carbon atoms and an aromatic hydrocarbon group having 6 to 15 carbon atoms.

  In the definition of the above formula (VI), specific examples of the “aromatic hydrocarbon group” include phenyl group, tolyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group and the like, and “heteroaromatic ring” Specific examples of `` group '' include furyl group, thionyl group, oxazolyl group, imidazolyl group, pyranyl group, pyridinyl group, acridinyl group, benzofuranyl group, benzothionyl group, benzopyranyl group, benzooxazolyl group, benzoimidazolyl group, etc. It is done.

In addition, the part of (R ₄₁ —O) p in the formula (VI) may be two or three groups within the above range. Specific examples include random or block combinations of ethyleneoxy and propyleneoxy groups, ethyleneoxy and isopropyloxy groups, ethyleneoxy and butyleneoxy groups, ethyleneoxy groups and isobutylene groups, and the like. . In the present invention, the surfactant having a polyoxyalkylene ether group is used alone or in combination, and it is effective to add 1 to 30% by mass, preferably 2 to 20% by mass in the developer. If the addition amount is small, the developability may be deteriorated. On the other hand, if the amount is too large, the development damage becomes strong and the printing durability of the printing plate may be deteriorated.

  Examples of the nonionic surfactant having a polyoxyalkylene ether group represented by the above formula (VI) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and polyoxyethylene stearyl ether. Polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether and polyoxyethylene naphthyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene methyl phenyl ether, polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether Kind.

  Surfactants can be used alone or in combination.

  The pH of the developer used in the plate-making method of the present invention is usually 11.0 to 12.7, preferably 11.5 to 12.5, from the viewpoint of damage during image formation and development of the exposed area.

Moreover, it is preferable that the electrical conductivity of the developing solution used by this invention is 3-30 mS / cm. If it is lower than normal, the elution of the photosensitive layer component on the surface of the aluminum plate support becomes difficult, and printing may be accompanied by stains. Conversely, if the range is exceeded, the salt concentration is high, so the elution of the photosensitive layer This is because the speed becomes extremely slow and a residual film may be formed in the unexposed area. Particularly preferred conductivity is in the range of 5-20 mS / cm.

(Exposure and development processing)
The lithographic printing plate precursor in the present invention is, for example, a carbon arc lamp, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a halogen lamp, a helium cadmium laser, an argon ion laser, an FD / YAG laser, a helium neolaser, An image can be formed on the surface of the aluminum plate support by image exposure with a conventionally known actinic ray such as a semiconductor laser (350 nm to 600 nm) and then developing with a developer. As the exposure light source, a laser of 350 to 600 nm is preferable.
In order to increase the curing rate of the photosensitive layer after image exposure and before development, a heating process may be performed at a temperature of 50 ° C. to 140 ° C. for 1 second to 5 minutes. When the heating temperature is in the above range, there is an effect of increasing the curing rate, and there is no residual film due to dark polymerization in the unexposed area.

  When a protective layer is provided on the photosensitive layer of the lithographic printing plate precursor according to the invention, using a developer, a method of simultaneously removing the protective layer and removing the unexposed portion of the photosensitive layer, Alternatively, a method is known in which the protective layer is first removed with water or warm water, and then the unexposed photosensitive layer is removed by development. These water or warm water can contain a preservative described in JP-A-10-10754, an organic solvent described in JP-A-8-278636, and the like.

  The developer used for developing the lithographic printing plate precursor according to the invention preferably contains a nonionic surfactant having a polyoxyalkylene ether group.

  The development of the lithographic printing plate precursor in the present invention with the developer is carried out by immersing the exposed lithographic printing plate precursor in the developer at a temperature of about 0 to 60 ° C., preferably about 15 to 40 ° C., according to a conventional method. For example, rubbing with a brush.

Further, when developing using an automatic developing machine, the developing solution becomes fatigued according to the amount of processing, so that the processing capability may be restored using a replenishing solution or a fresh developing solution. The lithographic printing plate precursor thus developed is usually washed with water, interface, as described in JP-A Nos. 54-8002, 55-1115045, 59-58431, etc. It is post-treated with a rinsing solution containing an active agent and the like, a desensitizing solution containing gum arabic, starch derivatives and the like. In the present invention, these treatments can be used in various combinations for the post-treatment of the lithographic printing plate precursor.
The printing plate obtained by the above treatment can be improved in printing durability by post-exposure treatment or heating treatment such as burning according to the method described in JP-A-2000-89478.
The planographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

Hereinafter, although an example and a comparative example explain the present invention in detail, the present invention is not limited to these. In addition, Example 1 and 2 shall be read as "reference example."

[Example 1]
Fabrication of support (1) Support 1: Anodized aluminum support Using a 1S aluminum plate with a thickness of 0.30 mm using a nylon suspension of No. 8 nylon brush and 800 mesh Pamiston, and its surface is grained And washed well with water. After etching by dipping in 10% by mass sodium hydroxide at 70 ° C. for 60 seconds, washed with running water, neutralized with 20% by mass nitric acid, and washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass aqueous nitric acid solution using a sinusoidal alternating current under the condition of V _A = 12.7 V at an anode time electricity of 300 coulomb / dm ² . The surface roughness was measured and found to be 0.45 μm (Ra indication). Subsequently, after being immersed in a 30% by weight sulfuric acid aqueous solution at 55 ° C. and desmutted for 2 minutes, a cathode was placed on a grained surface in a 20% by weight sulfuric acid aqueous solution at 33 ° C., and a current density of 5 A / dm ^2. And anodized for 50 seconds. The amount of the anodized film was 2.6 g / m ² . This was designated as Support 1.

2) Support 2: Support having an intermediate layer The following intermediate layer coating solution 1 was applied to the support 1 using a bar coater so as to have a dry coating amount of 30 mg / m ^2, and at 150 ° C. for 5 seconds. It dried and the support body 2 was obtained.

Intermediate layer coating solution 1
Tetraethyl silicate 16.0 parts by weight Methanol 5.0 parts by weight Phosphoric acid aqueous solution (85%) 2.5 parts by weight Pure water 16.0 parts by weight

  When the above components were mixed and stirred, heat was generated in about 30 minutes. After reacting by stirring for 60 minutes, the intermediate layer coating solution 1 was prepared by adding the following solution.

・ Methanol 1984 parts by mass ・ 1-Methoxy-2-propanol 100 parts by mass

(Preparation of photopolymerization type photosensitive lithographic printing plate precursor)
A photosensitive composition (1) having the following composition was applied onto the support 2 using a bar coater, and then dried at 90 ° C. for 1 minute to form a photosensitive layer. The mass of the photosensitive layer after drying was 1.35 g / m ² .

Photosensitive composition (1)
Ethylenically unsaturated bond-containing compound (A1) 1.0 part by weight Polymer binder (B1) 2.0 part by weight Sensitizing dye (D32) 0.15 part by weight Photopolymerization initiator (C1) 0.12 part by weight ε -Phthalocyanine (F1) dispersion 0.02 parts by mass Sensitization aid (G1) 0.5 parts by mass Fluorine nonionic surfactant Megafac F-780F
(Dainippon Ink & Chemicals, Inc.) 0.02 parts by mass Methyl ethyl ketone 26.0 parts by mass Propylene glycol monomethyl ether 26.3 parts by mass

On this photosensitive layer, a protective layer coating aqueous solution having the following composition was coated with a bar coater so that the dry coating weight was 2.5 g / m ² and dried at 120 ° C. for 1 minute to obtain a lithographic printing plate precursor. .

Protective layer coating aqueous solution composition Polyvinyl alcohol (saponification degree 95 mol%, polymerization degree 500) 75.0 parts by weight Polyvinylpyrrolidone (molecular weight 50,000) 18.0 parts by weight Polymer (hereinafter SP-1) 2.0 parts by weight Rubis Cole VA64W (50% aqueous solution, manufactured by BASF) 1.2 parts by weight Nonionic surfactant Piion D230 (manufactured by Takemoto Yushi) 2.0 parts by weight Nonionic surfactant Emarex 710 (manufactured by Nippon Emulsifier) 1.8 parts by weight

[Example 2]
A photosensitive lithographic printing plate precursor was obtained in the same manner as in Example 1 except that the intermediate layer coating solution 1 of Example 1 was changed to the following intermediate layer coating solution 2.

Intermediate layer coating solution 2
Tetraethyl silicate 4.0 parts by weight Compound 1 (below) 1.2 parts by weight Compound 2 (below) 11.0 parts by weight Methanol 5.0 parts by weight Phosphoric acid aqueous solution (85%) 2.5 parts by weight

  When the above components were mixed and stirred, heat was generated in about 30 minutes. After reacting by stirring for 60 minutes, the intermediate layer coating solution 1 was prepared by adding the following solution.

・ Methanol 2000 parts by mass ・ 1-Methoxy-2-propanol 100 parts by mass

Example 3
A photosensitive lithographic printing plate precursor was obtained in the same manner as in Example 2, except that the photosensitive composition (1) of Example 2 was changed to the following photosensitive composition (2).

Photosensitive composition (2)
Ethylenically unsaturated bond-containing compound (PELEX6661-O manufactured by DEGUSSA)
1.69 parts by mass Polymer binder (compound 3 below, mass average molecular weight = 80,000) 1.87 parts by mass Sensitizing dye (compound D76 below) 0.13 parts by mass Hexaarylbiimidazole photopolymerization initiator (black gold) 0.46 parts by mass ε-phthalocyanine (F1 below) dispersion (25% by mass methyl ethyl ketone dispersion) 1.70 parts by mass mercapto compound (compound SH-1 below) 0.34 parts by mass Fluorine-based Nonionic surfactant MegaFuck F-780F
(Dainippon Ink Chemical Co., Ltd.) 0.03 parts by mass Cuperon AL (Wako Pure Chemical Industries, Ltd. polymerization inhibitor)
Tricresyl phosphate 10% by weight solution 0.12 parts by weight Methyl ethyl ketone 27.0 parts by weight Propylene glycol monomethyl ether 26.7 parts by weight

Example 4
A photosensitive lithographic printing plate precursor was obtained in the same manner as in Example 3 except that the intermediate layer dry coating amount of Example 3 was changed to 100 mg / m ² .

[Comparative Example 1]
A photosensitive lithographic printing plate precursor was obtained in the same manner as in Example 1, except that the intermediate layer coating in Example 1 was omitted.

[Comparative Example 2]
A photosensitive lithographic printing plate precursor was obtained in the same manner as in Example 3 except that the intermediate layer coating in Example 3 was omitted.

[Comparative Example 3]
In Example 3, photosensitization was performed in the same manner as in Example 3 except that the following polymer binder (Compound 4, mass average molecular weight = 80,000) was used instead of the polymer binder (Compound 3) of the photosensitive composition. A sex lithographic printing plate precursor was obtained. This photosensitive composition is designated as photosensitive composition (3).

[Comparative Example 4]
In the above Comparative Example 3, a photosensitive lithographic printing plate was obtained in the same manner as in Comparative Example 3, except that the intermediate layer coating was omitted.

(Evaluation of halftone dot reproducibility)
The above photosensitive lithographic printing plate precursor is cut into a size of 700 mm on the top and 500 mm in width, and then loaded into a Violet semiconductor laser setter Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) manufactured by FUJIFILM Electronic Imaging Ltd. With an exposure amount of cm ² and a resolution of 2438 dpi, a 1% to 10% halftone dot was drawn at 1% intervals with an FM screen manufactured by Fuji Photo Film Co., Ltd. and TAFFETA 20. The plate after exposure is automatically sent to the connected automatic processor LP1250PLX (with brush), heated at 100 ° C. for 10 seconds, washed off with the protective layer, and subsequently developed at 28 ° C. for 20 seconds. It was. The developed plate was washed with a rinse bath and then sent to a gumming bath. The plate after gumming was discharged after drying with hot air to obtain a planographic printing plate on which a flat net was drawn. Here, a developer obtained by diluting a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water was used. As the gum solution, FP-2W manufactured by Fuji Photo Film Co., Ltd. diluted twice with water was used. The area ratio of halftone dots of the obtained lithographic printing plate was measured using CC-dot, and an average value of 1% to 5% was calculated. The results are shown in Table 1.

(Evaluation of adhesion of photosensitive layer components in automatic processor processing)
After the photosensitive lithographic printing plate is cut into a size of 800 mm on the top and 1030 mm in width, it is heated with an automatic processor LP1250PLX (with brush) at 100 ° C. for 10 seconds, and then the protective layer is washed away with water, followed by 28 ° C. Developed for 20 seconds. The developed plate was rinsed in a rinse bath and sent to a gumming bath. The plate after gumming was discharged after drying with hot air to obtain a planographic printing plate on which a flat net was drawn. Here, a developer obtained by diluting a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water was used. As the gum solution, FP-2W manufactured by Fuji Photo Film Co., Ltd. diluted twice with water was used. The presence or absence of the photosensitive layer component on the non-image area of the obtained lithographic printing plate was visually evaluated. The results are shown in Table 1.

(Evaluation of sediment accumulation in the developing tank of automatic processor)
After the photosensitive lithographic printing plate is cut to a size of 800 mm on the top and 1030 mm in width, it is heated with an automatic processor LP1250PLX (with brush) at 100 ° C. for 10 seconds, and then the protective layer is washed away with water and subsequently at 28 ° C. Developed for 20 seconds. The developed plate was rinsed in a rinse bath and sent to a gumming bath. The plate after gumming was discharged after drying with hot air to obtain a planographic printing plate on which a flat net was drawn. Here, a developer obtained by diluting a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water was used. As the gum solution, FP-2W manufactured by Fuji Photo Film Co., Ltd. diluted twice with water was used. This treatment was performed for 7 days at 200 plates / day. After the treatment, the self-propelled machine was stopped for 1 day, and then the developer was extracted and the amount of sediment deposited on the bottom of the developing tank was visually evaluated. The results are shown in Table 1.

(Measurement of aluminum elution amount in developer)
In the sediment deposition evaluation in the above-mentioned automatic developing machine developer tank, the developer was collected from the developer tank at the stage of 50 plate processing, and a plasma emission analyzer (ICPS-1000IV type, manufactured by Shimadzu Corporation) was used. Quantified. The results are shown in Table-1.

  From the above results, it can be seen that the lithographic printing plate precursor of the present invention suppresses dot loss and brush pressure dependency, has excellent halftone dot reproducibility, and reduces the generation of debris during development processing.

Claims (3)

An intermediate layer containing a metal oxide obtained by hydrolysis and polycondensation of an organometallic compound or an inorganic metal compound is provided on a hydrophilic support, and the following formulas (1) to (3) are provided on the intermediate layer. A negative photopolymerization type photosensitive lithographic printing plate precursor comprising a photopolymerizable photosensitive layer containing a binder polymer having the structural unit shown, and a protective layer containing a water-soluble resin.
In the formula, each of R ₁ and R ₂ independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ₃ represents a substituted alkyl group having 1 to 6 carbon atoms substituted with a hydroxyl group, and X represents _{-COOH, -CO-W} 1 -L represents a functional group selected from 1 -COOH and -SO ₃ H, _{W 1} represents an oxygen atom, a sulfur atom or -NH- group, _{L 1} is a divalent organic group Y represents —CO—O—CH ₂ —CH═CH ₂ group, —CO—W ₂ —L ₂ —O—CO—CR ₄ ═CH ₂ group, and W ₂ represents oxygen atom, sulfur atom or —NH— group, L ₂ represents a divalent organic group, R ₄ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, W ₃ represents an oxygen atom, a sulfur atom or a —NH— group. , _{R 5} is an alkyl group having an alkyl group having 1 to 18 carbon atoms, an alicyclic structure having from 5 to 20 carbon atoms A group having an aromatic ring prime 6-20.   2. The negative photopolymerizable photosensitive lithographic printing plate precursor according to claim 1, wherein the intermediate layer containing a metal oxide contains an organosilicone compound having a functional group capable of causing addition polymerization by radicals. The negative photopolymerizable photosensitive lithographic printing plate precursor as claimed in claim 1, wherein the photopolymerizable photosensitive layer contains the following components (i) to (v).
(I) a sensitizing dye having an absorption maximum in a wavelength range of 350 nm to 450 nm,
(Ii) hexaarylbiimidazole compound,
(Iii) an addition polymerizable compound having an ethylenically unsaturated double bond,
(Iv) the binder polymer according to claim 1, and (v) at least one selected from 2-mercaptobenzothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazole and a compound represented by the following formula (4): Compound.
In the formula, R ₆ represents a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, an alkyl group having an alicyclic structure having 5 to 20 carbon atoms, or a group having an aromatic ring having 6 to 20 carbon atoms. X represents an oxygen atom, a sulfur atom or —N (R ₇ ) —, wherein R ₇ is a linear or branched alkyl group having 1 to 18 carbon atoms, or an alkyl having an alicyclic structure having 5 to 20 carbon atoms. A group or a group having an aromatic ring having 6 to 20 carbon atoms is shown.