JP2007206600A - Photosensitive lithographic printing plate material and plate making method using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate material, which is suitable for exposure by a laser beam in a range of 350 nm to 450 nm in an emission wavelength, which has a good safe writability, and also which is superior in printing durability, linearity and printing performance, and to provide a plate making method using the same. <P>SOLUTION: On a support having a hydrophilic surface, the photosensitive lithographic printing plate material has at least (A) a spectral sensitization agent, (B) a polymerizable ethylenically unsaturated double bond-containing compound, (C) a hexaaryl biimidazole, (D) a thiol compound, and (E) a photosensitive layer containing a photopolymerizable composition including a polymer bonding material. The photopolymerizable composition includes (A) a compound of a defined structure as the spectral sensitization agent, and (B) an ethylenically unsaturated double bond-containing compound with an urethane bond in a molecule as the polymerizable ethylenically unsaturated double bond-containing compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In recent years, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread, and in printing plate preparation technology for offset printing, directivity is determined according to digitized image information. A so-called CTP system that scans a high laser beam and directly records it on a photosensitive lithographic printing plate has been developed, and its practical application is progressing.

  Among these, in the field of printing that requires a relatively high printing durability, it is known to use a negative photosensitive lithographic printing plate material having a polymerization type photosensitive layer containing a polymerizable compound. (For example, refer to Patent Documents 1 and 2.) In particular, a technique has been proposed for achieving high sensitivity by introducing a titanocene compound into a photopolymerization initiator (see, for example, Patent Document 3).

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

  And, a high-power and small-sized blue-violet laser with a wavelength of 390 to 430 nm can be easily obtained, and by developing a photosensitive lithographic printing plate suitable for this laser wavelength, a bright room has been developed. (For example, see Patent Documents 4, 5 and 6.) In addition, a printing plate material containing biimidazole in a photosensitive layer with improved safe light property under a yellow light is known (see, for example, Patent Documents 7 and 8).

However, these printing plate materials still have insufficient printing durability, and the so-called linearity differs between the size of dots (halftone dots) based on image output data and the size of dots (halftone dots) on the printing plate. In addition, there was a problem that the scumming recovery property was slow when the printing was resumed after the printing was once stopped after printing, and the printing performance was insufficient.
JP-A-1-105238 JP-A-2-127404 Japanese Patent No. 2764288 JP 2000-35673 A JP 2000-98605 A JP 2001-264978 A JP 2001-194882 A JP 2002-214784 A

  The present invention has been made in view of the above problems, and its purpose is suitable for exposure with laser light having an emission wavelength in the range of 350 nm to 450 nm, and has good safelight properties, printing durability, It is an object of the present invention to provide a photosensitive lithographic printing plate material excellent in linearity and printing performance and a plate making method using the same.

  The above-described problems of the present invention are solved by the following means.

  1. On a support having a hydrophilic surface, at least (A) a spectral sensitizer, (B) a polymerizable ethylenically unsaturated double bond-containing compound, (C) a hexaarylbiimidazole, (D) a thiol compound, and (E) In a photosensitive lithographic printing plate material having a photosensitive layer containing a photopolymerizable composition containing a polymer binder, the photopolymerizable composition has the general formula (1) as (A) a spectral sensitizer. And (B) an ethylenically unsaturated double bond-containing compound having a urethane bond in the molecule as a polymerizable ethylenically unsaturated double bond-containing compound. Sex lithographic printing plate material.

(In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms, or an optionally substituted alkyl group having 1 to 1 carbon atoms. 20 alkyl groups, C1-C12 alkoxy groups, or

Represents. R ₆ and R ₇ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkenyl group, or a substituent. Represents a good saturated hydrocarbon group, aromatic group or heteroaromatic group. R ₆ and R ₇ may be combined with an alkyl group having 1 to 20 carbon atoms, an alkenyl group, or an alkyl group or alkenyl group which may have a substituent to form a ring. R ₈ and R ₉ each represent an alkyl group having 2 to 10 carbon atoms, an alkyl group that may have a substituent having 2 to 10 carbon atoms, or an aryl group having 5 to 10 carbon atoms. Further, two adjacent R _{1 to} R ₉ , R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ , R ₆ and R ₇ , R ₃ and R ₈ ( R ₉ ), R ₅ and R ₉ (R ₈ ) may be combined with one or a combination of two or more to form a ring. )
2. 2. The photosensitive lithographic printing plate material as described in 1 above, wherein the ethylenically unsaturated double bond-containing compound having a urethane bond in the molecule is a compound represented by the general formula (2).

(Where Q is

Represents. R represents an alkyl group, a hydroxyalkyl group or an aryl group. R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or an alkoxyalkyl group, and R ₃ represents a hydrogen atom, a methyl group or an ethyl group. X ₁ represents a saturated hydrocarbon group, an aromatic hydrocarbon residue having 6 to 24 carbon atoms, or an alkyl group residue having an aromatic hydrocarbon group. X ₂ represents a saturated hydrocarbon residue having 2 to 8 carbon atoms. D ₁ and D ₂ are saturated hydrocarbon residues and may form a ring together with the nitrogen atom. In the case of forming a ring with a nitrogen atom, (b) of Q is included in the ring as a divalent or trivalent coupler. Z represents a hydrogen atom, a saturated hydrocarbon group having 1 to 3 carbon atoms, or a —C _k H _2k O—CONH (X ₁ —NHCOO) _b —X ₂ (—OOC—C (R ₃ ) ═CH ₂ ) group. . a represents an integer of 0 to 4, b represents 0 or 1, and k represents an integer of 1 to 12. m represents 2, 3 or 4 depending on the valence of Q, and n represents an integer of 1 to m. )
3. 3. The photosensitive lithographic printing plate material as described in 1 or 2 above, which has at least a photosensitive layer and an oxygen blocking layer containing polyvinyl alcohol as a main component on a support having a hydrophilic surface.

  4). A plate making method in which the photosensitive lithographic printing plate material according to any one of 1 to 3 is subjected to image exposure with a laser beam having an oscillation wavelength of 350 to 440 nm, heated to 100 to 130 ° C., and then developed with an alkaline aqueous solution. The method for making a photosensitive lithographic printing plate material according to claim 1, wherein the development is carried out with an alkaline developer having a pH of 11 to 12.6 that does not contain an organic solvent.

  According to the configuration of the present invention, a photosensitive lithographic printing plate material suitable for exposure with a laser beam having an emission wavelength in the range of 350 nm to 450 nm, having good safe light properties, and excellent printing durability, linearity and printing performance, and A plate making method using the same can be provided.

The photosensitive lithographic printing plate material of the present invention comprises, on a support having a hydrophilic surface, at least (A) a spectral sensitizer, (B) a polymerizable ethylenically unsaturated double bond-containing compound, (C) hexa In a photosensitive lithographic printing plate material having a photosensitive layer containing a photopolymerizable composition comprising an arylbiimidazole, (D) a thiol compound, and (E) a polymer binder, the photopolymerizable composition comprises ( A) a compound containing the compound represented by the general formula (1) as a spectral sensitizer and (B) an ethylene having a urethane bond (—NHCOO—) in the molecule as a polymerizable ethylenically unsaturated double bond-containing compound. In the following, the present invention and components thereof will be described in detail.

((A) Spectral sensitizer)
The spectral sensitizer according to the present invention increases the sensitivity of the polymerization initiator with respect to image exposure. In the present invention, at least the compound represented by the general formula (1) is used as the spectral sensitizer. It is contained in the photopolymerizable composition which concerns on.

  The spectral sensitizer according to the present invention is preferably a compound that absorbs light having a wavelength in the emission wavelength region of the recording light source. Specifically, a compound having an absorption maximum from 350 nm to 450 nm is preferable, and a compound having an absorption maximum from 350 to 410 nm is more preferable.

(In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms, or an optionally substituted alkyl group having 1 to 1 carbon atoms. 20 alkyl groups, C1-C12 alkoxy groups, or

Represents. R ₆ and R ₇ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkenyl group, or a substituent. Represents a good saturated hydrocarbon group, aromatic group or heteroaromatic group. R ₆ and R ₇ may be combined with an alkyl group having 1 to 20 carbon atoms, an alkenyl group, or an alkyl group or alkenyl group which may have a substituent to form a ring. R ₈ and R ₉ each represent an alkyl group having 2 to 10 carbon atoms, an alkyl group that may have a substituent having 2 to 10 carbon atoms, or an aryl group having 5 to 10 carbon atoms. Further, two adjacent R _{1 to} R ₉ , R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ , R ₆ and R ₇ , R ₃ and R ₈ ( R ₉ ), R ₅ and R ₉ (R ₈ ) may be combined with one or a combination of two or more to form a ring. )
Hereinafter, preferred specific examples of the spectral sensitizer according to the present invention will be given. The present invention is not limited to these.

  In the present invention, in addition to the spectral sensitizer represented by the general formula (1), spectral sensitizers having different chemical structures may be used in combination. Specific examples of spectral sensitizers that can be used in combination include optical brighteners described in JP2003-295426A, spectral sensitizers described in JP2003-211901, and general formulas described in JP2003-21895A. A compound having a structure represented by (I), a compound having a structure represented by general formula (I) in JP-A-2003-21894, and a spectral sensitizer having a specific structure in JP-A-2002-351072 Spectral sensitizer having a specific structure of JP-A No. 2002-351071, SPECTRAL SENSITIZER having a specific structure (pyrrolopyrrole ring) of JP-A No. 2002-351655, Spectral sensitization of JP-A No. 2002-268239 Sensitizer, spectral sensitizer of JP 2002-268238 A, spectral sensitizer of JP 2002-268204 A, general formula of JP 2002-221790 A A compound having a structure represented by I), a compound having a structure represented by general formula (I) in JP-A No. 2002-202598, a carbazole-based spectral sensitizer in JP-A No. 2001-042524, No. 2000-309724, No. 2000-258910, No. 2000-206690, Naphtho [1,8-b, c] furan-5-one derivative, Examples thereof include merocyanine dyes disclosed in Japanese Utility Model Laid-Open No. 2000-147763, and carbonyl compounds disclosed in Japanese Patent Application Laid-Open No. 2000-098605.

  In addition to the above exemplified spectral sensitizers, examples of preferable spectral sensitizers that can be used in combination include, for example, cyanine, merocyanine, porphyrin, spiro compound, ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, Phenothiazine, acridine, azo compound, diphenylmethane, triphenylmethane, triphenylamine, coumarin derivative, quinacridone, indigo, styryl, pyrylium compound, pyromethene compound, pyrazolotriazole compound, benzothiazole compound, barbituric acid derivative, thiobarbitur An acid derivative, a keto alcohol borate complex, etc. can also be mentioned.

  The addition amount of the spectral sensitizer according to the present invention in the photosensitive layer is arbitrary, but is preferably in the range of 0.1 to 20% by mass with respect to the total mass of the photosensitive layer. Furthermore, it is preferably 0.8 to 15% by mass. More specifically, when the composition of the photosensitive lithographic printing plate material is used, an addition amount in which the absorbance of the reflection spectrum using an integrating sphere at the laser wavelength to be used is in the range of 0.2 to 2.0 is preferable. More preferably, the addition amount is an absorbance of 0.3 to 1.2.

  These spectral sensitizers may be used alone or in combination of two or more.

((B) Addition-polymerizable ethylenic double bond-containing compound (hereinafter sometimes referred to simply as (B))
The (B) addition-polymerizable ethylenic double bond-containing compound of the present invention is an ethylenic double bond-containing compound that can be polymerized by image exposure, and the polymerizable composition according to the present invention includes the (B) polymerization. It is characterized by including an ethylenically unsaturated double bond-containing compound having a urethane bond (-NHCOO-) in the molecule as a possible ethylenically unsaturated double bond-containing compound. As the ethylenically unsaturated double bond-containing compound having a urethane bond in the molecule, compounds having various structures can be used, but it is preferable to contain a compound represented by the above general formula (2).

(Where Q is

Represents. R represents an alkyl group, a hydroxyalkyl group or an aryl group. R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or an alkoxyalkyl group, and R ₃ represents a hydrogen atom, a methyl group or an ethyl group. X ₁ represents a saturated hydrocarbon group, an aromatic hydrocarbon residue having 6 to 24 carbon atoms, or an alkyl group residue having an aromatic hydrocarbon group. X ₂ represents a saturated hydrocarbon residue having 2 to 8 carbon atoms. D ₁ and D ₂ are saturated hydrocarbon residues and may form a ring together with the nitrogen atom. In the case of forming a ring with a nitrogen atom, (b) of Q is included in the ring as a divalent or trivalent coupler. Z represents a hydrogen atom, a saturated hydrocarbon group having 1 to 3 carbon atoms, or a —C _k H _2k O—CONH (X ₁ —NHCOO) _b —X ₂ (—OOC—C (R ₃ ) ═CH ₂ ) group. . a represents an integer of 0 to 4, b represents 0 or 1, and k represents an integer of 1 to 12. m represents 2, 3 or 4 depending on the valence of Q, and n represents an integer of 1 to m. )
In the general formula (2), examples of the aromatic hydrocarbon residue represented by X ₁ include a phenylene group, a tolyl group, a xylene group, an alkyldiphenyl group, and a naphthyl group. Among these, a xylene group is preferable.

  Hereinafter, preferred specific examples of the compound containing an ethylenically unsaturated double bond having a urethane bond in the molecule according to the present invention are shown below. The present invention is not limited to these.

  In the present invention, addition-polymerizable ethylenic double bond-containing compounds having various structures can be used in combination with the addition-polymerizable ethylenic double bond-containing compound.

  Addition-polymerizable ethylenic double bond-containing compounds that can be used in combination include general radical-polymerizable monomers and a plurality of addition-polymerizable ethylenic double bonds in the molecule generally used for UV curable resins. Polyfunctional monomers and polyfunctional oligomers can be used. The compound is not limited, but preferred examples include 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glycerol acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, tetrahydro Furfuryloxyhexanolide acrylate, acrylate of ε-caprolactone adduct of 1,3-dioxane alcohol, monofunctional acrylic acid esters such as 1,3-dioxolane acrylate, or these acrylates as methacrylate, itaconate, crotonate, maleate Methacrylic acid, itaconic acid, crotonic acid, maleic acid esters such as ethylene glycol diacrylate , Triethylene glycol diacrylate, pentaerythritol diacrylate, hydroquinone diacrylate, resorcin diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, dipentylate of hydroxypentylate neopentyl glycol, Diacrylate of neopentyl glycol adipate, Diacrylate of ε-caprolactone adduct of neopentyl glycol hydroxypivalate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1, Ε-caprolactone adduct of 3-dioxane diacrylate, tricyclodecane dimethylol acrylate, tricyclodecane dimethylol acrylate Difunctional acrylic acid esters such as diglycidyl ether diacrylate of 1,6-hexanediol, or methacrylic acid, itaconic acid, crotonic acid, maleic acid ester in which these acrylates are replaced with methacrylate, itaconate, crotonate, maleate, For example, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dipentaerythritol Ε-caprolactone adduct of hexaacrylate, pyrogallol triacrylate Polyfunctional acrylic acid esters such as propionic acid / dipentaerythritol triacrylate, propionic acid / dipentaerythritol tetraacrylate, hydroxypivalylaldehyde-modified dimethylolpropane triacrylate, or these acrylates with methacrylate, itaconate, crotonate, Examples thereof include methacrylic acid, itaconic acid, crotonic acid, and maleic acid ester instead of maleate.

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

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

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

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

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

(Polymerization initiator)
The polymerization initiator has a function of initiating a polymerization reaction of a compound that can be polymerized by image exposure, and as a polymerization initiator according to the present invention, various polymerization initiators that are generally used in the past are used. However, it is characterized by containing at least a hexaarylbiimidazole compound.

[(C) hexaarylbiimidazole compound]
Next, the hexaarylbiimidazole compound contained as a photopolymerization initiator according to the present invention will be described.

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

  In the present invention, it is essential to contain a hexaarylbiimidazole (HABI, triaryl-imidazole dimer) compound.

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

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

  The amount of HABI photoinitiator is typically in the range of 0.01-30% by weight, preferably 0.5-20% by weight, based on the total weight of the non-volatile components of the photosensitive composition.

  The ratio of the biimidazole compound to the compound represented by the general formula (1) is preferably 0.5% by mass to 15% by mass, and particularly preferably 1.5% by mass to 8% by mass.

(Chain transfer agent)
A chain transfer agent is a compound added to a polymerization reaction system for the purpose of adjusting the degree of polymerization of a polymer, etc., and has a function of changing the type of chain transfer body in the course of a chain polymerization reaction. .

  The chain transfer agent according to the present invention is preferably a radical chain transfer agent as described in EP 107792 in order to promote or control the polymerization reaction of the polymerizable compound according to the present invention. Specific examples of preferable radical chain transfer agents include thiol compounds.

  In the present invention, at least a thiol compound is contained in the polymerizable composition (photosensitive composition) according to the present invention. Sensitivity can be improved by containing the thiol compound.

[(D) Thiol Compound]
The thiol compound according to the present invention is a compound that gives hydrogen to an imidazole radical formed by cleavage of biimidazole, becomes a radical, and has radical polymerization initiation ability, and is known as a hydrogen donating compound. It has been.

  Examples of the thiol compound include alkylthiol derivatives, hydroxyalkylthiol derivatives, mercaptobenzothiazole derivatives, mercaptobenzimidazole derivatives, mercaptobenzoxazole derivatives, mercaptotriazole derivatives, and mercaptotetrazole derivatives.

  As the thiol compound, a compound represented by the following general formula (RCT) is preferably used.

In the general formula (RCT), X represents a sulfur, nitrogen or oxygen atom. However, in the case of a nitrogen atom, NH is represented. Y ₁ , Y ₂ and Y ₃ each independently represent a nitrogen or carbon atom. Z represents a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group, and n represents an integer of 0 to 5.

  The content of the compound represented by the general formula (RCT) is preferably 0.1% by mass to 2.5% by mass and particularly preferably 0.15% by mass to 1.0% by mass with respect to the photosensitive layer. . Moreover, 0.1 mass%-2.5 mass% are preferable with respect to the compound represented by General formula (1), and 0.15 mass%-0.8 mass% are especially preferable.

  Hereinafter, preferred specific examples of the thiol compound according to the present invention are shown. The present invention is not limited to these.

((E) polymer binder)
The polymer binder according to the present invention has a function of retaining each component contained in the photosensitive composition or the photosensitive layer.

  Examples of the polymer binder used in the present invention include acrylic polymers, polyvinyl butyral resins, polyurethane resins, polyamide resins, polyester resins, epoxy resins, phenol resins, polycarbonate resins, polyvinyl butyral resins, polyvinyl formal resins, shellacs, and others. Natural resins can be used. Two or more of these may be used in combination.

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

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

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

  Furthermore, in the polymer binder of the present invention, monomers described in the following (1) to (14) can be used as other copolymerization monomers.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  The vinyl polymer can be produced by ordinary solution polymerization. It can also be produced by bulk polymerization or suspension polymerization. The polymerization initiator is not particularly limited, and examples thereof include azobis-based radical generators such as 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (2-methylbutyro). Nitrile) and the like. Moreover, the usage-amount of these polymerization initiators is 0.05-10.0 mass parts normally with respect to 100 mass parts of whole monomers used for forming a copolymer (preferably 0.1-5 mass). Part). Examples of the solvent used for the solution polymerization include ketone-based, ester-based, and aromatic-based organic solvents, among which toluene, ethyl acetate, benzene, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, and the like. In general, a good solvent for an acrylic polymer is used, and a solvent having a boiling point of 60 to 120 ° C. is particularly preferable. In the case of solution polymerization, the above solvent is used, and the reaction temperature is usually 40 to 120 ° C. (preferably 60 to 110 ° C.) and the reaction time is usually 3 to 10 hours (preferably 5 to 8 hours). it can. After completion of the reaction, the solvent is removed to obtain a copolymer. Further, the double bond introduction reaction described later can be carried out without removing the solvent.

  The molecular weight of the resulting copolymer can be adjusted by adjusting the solvent used and the reaction temperature. The solvent, reaction temperature, and the like used to obtain the desired molecular weight copolymer can be appropriately determined depending on the monomer used. Moreover, the molecular weight of the copolymer obtained can also be adjusted by mixing a specific solvent with the said solvent. Examples of such solvents include mercaptans (eg, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, etc.), carbon tetrachloride (eg, carbon tetrachloride, butyl chloride, propylene chloride). Etc.). The ratio of mixing these solvents with the solvent used in the above reaction can be appropriately determined depending on the monomer, solvent, reaction conditions, etc. used in the reaction.

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

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

  A known method can be used for the addition reaction of a compound having a (meth) acryloyl group and an epoxy group in the molecule to a carboxyl group present in the molecule of the vinyl copolymer. For example, the reaction temperature is 20 to 100 ° C., preferably 40 to 80 ° C., particularly preferably at the boiling point (under reflux) of the solvent used, and the reaction time is 2 to 10 hours, preferably 3 to 6 hours. Can do. Examples of the solvent to be used include those used in the polymerization reaction of the vinyl copolymer. In addition, after the polymerization reaction, the solvent can be used as it is for the introduction reaction of the alicyclic epoxy group-containing unsaturated compound without removing the solvent. The reaction can be performed in the presence of a catalyst and a polymerization inhibitor as necessary.

  Here, the catalyst is preferably an amine-based or ammonium chloride-based material, and specifically, the amine-based material is triethylamine, tributylamine, dimethylaminoethanol, diethylaminoethanol, methylamine, ethylamine, n-propylamine. , Isopropylamine, 3-methoxypropylamine, butylamine, allylamine, hexylamine, 2-ethylhexylamine, benzylamine, and the like, and ammonium chloride-based substances include triethylbenzylammonium chloride and the like.

  When using these as a catalyst, what is necessary is just to add in 0.01-20.0 mass% with respect to the alicyclic epoxy group containing unsaturated compound to be used. In addition, as polymerization inhibitors, hydroquinone, hydroquinone monomethyl ether, tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone, methyl hydroquinone, p-benzoquinone, methyl-p-benzoquinone, tert-butyl-p-benzoquinone 2,5-diphenyl-p-benzoquinone and the like, and the amount used is 0.01 to 5.0% by mass with respect to the alicyclic epoxy group-containing unsaturated compound to be used. The progress of the reaction may be determined by measuring the acid value of the reaction system and stopping the reaction when the acid value becomes zero.

  A known method can be used for the addition reaction of a compound having a (meth) acryloyl group and an isocyanate group in the molecule to a hydroxyl group present in the molecule of the vinyl polymer. For example, the reaction temperature is usually 20 to 100 ° C., preferably 40 to 80 ° C., particularly preferably at the boiling point (under reflux) of the solvent used, and the reaction time is usually 2 to 10 hours, preferably 3 to 6 hours. It can be carried out. Examples of the solvent to be used include solvents used in the polymerization reaction of the polymer copolymer. Further, after the polymerization reaction, the solvent can be used as it is for the introduction reaction of the isocyanate group-containing unsaturated compound without removing the solvent. The reaction can be performed in the presence of a catalyst and a polymerization inhibitor as necessary. Here, the catalyst is preferably a tin-based or amine-based substance, and specific examples include dibutyltin laurate and triethylamine.

  The catalyst is preferably added in the range of 0.01 to 20.0 mass% with respect to the compound having a double bond to be used. In addition, as polymerization inhibitors, hydroquinone, hydroquinone monomethyl ether, tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone, methyl hydroquinone, p-benzoquinone, methyl-p-benzoquinone, tert-butyl-p-benzoquinone 2,5-diphenyl-p-benzoquinone and the like, and the amount used is usually 0.01 to 5.0% by mass with respect to the isocyanate group-containing unsaturated compound to be used. The progress of the reaction may be determined by determining the presence or absence of an isocyanato group in the reaction system using an infrared absorption spectrum (IR), and stopping the reaction when the absorption disappears.

  The above-mentioned vinyl polymer having a carboxyl group and a polymerizable double bond in the side chain used in the present invention is preferably 50 to 100% by mass and 100% by mass in the total polymer binder. More preferred.

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

(Various additives)
In addition to the above-described components, the photosensitive composition according to the present invention is used to prevent unnecessary polymerization of an ethylenic double bond monomer that can be polymerized during the production or storage of a photosensitive lithographic printing plate. It is desirable to add a polymerization inhibitor. Suitable polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol) 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine cerium salt, 2-t-butyl-6- (3-t-butyl-2-hydroxy-5) -Methylbenzyl) -4-methylphenyl acrylate and the like.

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

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

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

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

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

  Moreover, the said composition can contain surfactant as a coating property improving agent in the range which does not impair the performance of this invention. Of these, fluorine-based surfactants are preferred.

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

  Moreover, as a solvent used when preparing the photosensitive composition of the photopolymerizable photosensitive layer according to the present invention, for example, in the case of alcohol: polyhydric alcohol derivatives, sec-butanol, isobutanol, n-hexanol, Benzyl alcohol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, ethers: propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ketones, aldehydes: diacetone Preferable examples include alcohol, cyclohexanone, methylcyclohexanone, and esters: ethyl lactate, butyl lactate, diethyl oxalate, methyl benzoate and the like.

  Although the photosensitive composition according to the present invention has been described above, the photosensitive lithographic printing plate according to the present invention is prepared by mixing and preparing the above-mentioned compositions so as to have the above ratios, and coating the mixture on an aluminum support. It is constituted by.

(Protective layer: oxygen barrier layer)
It is preferable to provide a protective layer on the upper side of the photosensitive layer according to the present invention.

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

  In this invention, it can apply suitably for the photosensitive lithographic printing plate material which has a protective layer which has polyvinyl alcohol as a main component.

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

  When a protective layer is provided on the photosensitive lithographic printing plate of the present invention, the peeling force between the photosensitive layer and the protective layer is preferably 35 mN / mm or more, more preferably 50 mN / mm or more, and even more preferably 75 mN / mm or more. is there. Preferred examples of the protective layer composition include those described in Japanese Patent Application No. 8-161645.

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

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

  When providing a protective layer, the thickness is preferably from 0.1 to 5.0 μm, particularly preferably from 0.5 to 3.0 μm.

(Support)
The photosensitive composition according to the present invention is coated on a support to constitute a photosensitive lithographic printing plate.In the present invention, as the support, an aluminum support having a hydrophilic surface is used. Pure aluminum or aluminum alloy may be used.

  Various aluminum alloys can be used as the support, and for example, alloys of metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum are used. .

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

  As a roughening method used in the present invention, roughening is performed by electrolysis, but before that, roughening can be performed by, for example, a mechanical method.

The mechanical roughening method used is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The roughening by the brush polishing method is, for example, by rotating a rotating brush using a bristle having a diameter of 0.2 to 0.8 mm, and for example, volcanic ash particles having a particle size of 10 to 100 μm on water. While supplying the uniformly dispersed slurry, the brush can be pressed. The roughening by honing polishing is performed by, for example, uniformly dispersing volcanic ash particles having a particle size of 10 to 100 μm in water, injecting pressure from a nozzle, and causing the surface to collide obliquely with the support surface. Can do. Further, for example, abrasive particles having a particle size of 10 to 100 μm are applied to the support surface so as to be present at a density of 2.5 × 10 ³ to 10 × 10 ³ particles / cm ² at intervals of 100 to 200 μm. Roughening can also be performed by laminating the sheets and applying a pressure to transfer the rough surface pattern of the sheet.

After the surface is roughened by the mechanical surface roughening method, it is preferable to immerse in an aqueous solution of acid or alkali in order to remove the abrasive that has digged into the surface of the support, formed aluminum scraps, and the like. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an aqueous alkali solution such as sodium hydroxide. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. After the immersion treatment with an alkaline aqueous solution, it is preferable to carry out a neutralization treatment by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

In the present invention, as a roughening method, roughening by electrolysis is performed. In this method, the surface is electrochemically roughened in an acidic electrolytic solution, and the acidic electrolytic solution has an effective value of 30 A in a hydrochloric acid or nitric acid solution having a concentration of 0.4% by mass to 2.8% by mass. / dm ² or more 100A / dm ² or less at a current density of 10 seconds to 120 seconds, performing electrolytic graining. The concentration of hydrochloric acid or nitric acid is more preferably 1% by mass or more and 2.3% by mass or less. Current density is more preferably 30A / dm ² or more 80A / dm ² or less, further preferably 40A / dm ² or more 75A / dm ² or less.

The temperature at which the electrolytic surface-roughening method is performed is not particularly limited, but is preferably in the range of 5 ° C. to 80 ° C., more preferably in the range of 10 ° C. to 60 ° C. The applied voltage is not particularly limited, but is preferably performed by applying a voltage in the range of 1 to 50 volts, and more preferably in the range of 10 to 30 volts. Quantity of electricity is not particularly limited, it is preferable to use a range of 5000 C / dm ^2, still preferably selected from the range of 100~2000c / dm ^2.

  If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

After the surface is roughened by the electrolytic surface roughening method, it is preferably immersed in an acid or alkaline aqueous solution in order to remove aluminum scraps on the surface. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

Following the electrolytic surface roughening treatment, an anodic oxidation treatment can be performed. There is no restriction | limiting in particular in the method of the anodizing process which can be used in this invention, A well-known method can be used. By performing the anodizing treatment, an oxide film is formed on the support. For the anodizing treatment, a method of electrolyzing an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% as an electrolytic solution at a current density of 1 to 10 A / dm ² is preferably used. A method of electrolysis at a high current density in sulfuric acid described in Japanese Patent No. 1,412,768, a method of electrolysis using phosphoric acid described in Japanese Patent No. 3,511,661, chromic acid, Examples thereof include a method using a solution containing one or more oxalic acid, malonic acid and the like. The formed anodic oxidation coating amount is suitably 1 to 50 mg / dm ² , preferably 10 to 40 mg / dm ² . The anodized coating amount is obtained by, for example, immersing an aluminum plate in a chromic phosphate solution (85% phosphoric acid solution: 35 ml, prepared by dissolving 20 g of chromium (IV) oxide in 1 L of water) to dissolve the oxide film, It is obtained from mass change measurement before and after dissolution of the coating on the plate.

  In the present invention, the support is preferably treated with a sodium silicate solution having a temperature of 20 ° C. or more and 50 ° C. or less after the anodizing treatment. The temperature is preferably 20 ° C. or higher and 50 ° C. or lower, and more preferably 20 ° C. or higher and 45 ° C. or lower. If it is less than 20 ° C., it may become dirty and recovery may be worsened. Further, if it is higher than 50 ° C., the printing durability may be deteriorated. The concentration of sodium silicate is not particularly limited, but is preferably 0.01% or more and 35% or less, and more preferably 0.1% or more and 5% or less.

  In the present invention, the support is preferably treated with a polyvinylphosphonic acid solution having a temperature of 20 ° C. or more and 70 ° C. or less after the anodizing treatment. The temperature is preferably 20 ° C. or higher and 70 ° C. or lower, and more preferably 30 ° C. or higher and 65 ° C. or lower. If it is less than 20 ° C., it may become dirty and recovery may be worsened. On the other hand, if it is higher than 70 ° C., the printing durability may be deteriorated. The concentration of the polyvinylphosphonic acid solution is not particularly limited, but is preferably 0.01% or more and 35% or less, and more preferably 0.1% or more and 5% or less.

(Application)
The prepared photosensitive composition (photopolymerizable photosensitive layer coating solution) can be coated on a support by a conventionally known method and dried to prepare a photosensitive lithographic printing plate material. Examples of coating methods for the coating liquid include air doctor coater method, blade coater method, wire bar method, knife coater method, dip coater method, reverse roll coater method, gravure coater method, cast coating method, curtain coater method and extrusion coater method. I can list them.

  If the drying temperature of the photosensitive layer is low, sufficient printing durability cannot be obtained. If the drying temperature is too high, not only marangoni is produced but also fogging of a non-image area is caused. The preferable drying temperature range is preferably 60 to 160 ° C, more preferably 80 to 140 ° C, and particularly preferably 90 to 120 ° C.

(Image recording method)
As a light source for recording an image on the photosensitive lithographic printing plate according to the present invention, it is preferable to use a laser beam having an emission wavelength of 350 to 450 nm.

  As a light source for exposing the photosensitive lithographic printing plate of the present invention, for example, a He-Cd laser (441 nm), a combination of Cr: LiSAF and SHG crystal (430 nm) as a solid laser, KNbO3 as a semiconductor laser system, ring resonance Examples include a vessel (430 nm), AlGaInN (350 nm to 450 nm), an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm), and the like.

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

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

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

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

(Developer)
The exposed portion of the photosensitive layer on which the image has been recorded is cured. By developing this with an alkaline developer, the unexposed areas are removed and image formation becomes possible. As such a developer, a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium, ammonium; dibasic sodium phosphate, potassium, ammonium; sodium bicarbonate, potassium, ammonium; sodium carbonate, potassium, ammonium; sodium bicarbonate, potassium, ammonium An alkali developer using an inorganic alkaline agent such as sodium borate, potassium, ammonium; sodium hydroxide, potassium, ammonium and lithium;

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

  These alkali agents are used alone or in combination of two or more. In addition, an organic solvent such as an anionic surfactant, an amphoteric surfactant or an alcohol can be added to the developer as required, and a developer containing an anionic surfactant is particularly preferably used. it can.

(Other additives)
In addition to the above, the following additives can be added to the developer in order to improve development performance. For example, neutral salts such as NaCl, KCl and KBr described in JP-A-58-75152, complexes such as [Co (NH ₃ )] ₆ Cl ₃ described in JP-A-59-121336, JP-A-56-142258 Amphoteric polymer electrolytes such as vinylbenzyltrimethylammonium chloride and sodium acrylate copolymers described in No. 59, organometallic surfactants containing Si, Ti, etc. described in JP-A-59-75255, JP-A-59-84241 And organic boron compounds described in the above-mentioned item.

  The photosensitive lithographic printing plate material of the present invention is image-exposed with a laser beam having an emission wavelength in the wavelength range of 350 to 450 nm and developed with an alkaline developer having a pH of 11 to 12.6 containing an anionic surfactant. Is a preferred embodiment.

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

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

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

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

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the examples, “parts” represents “parts by mass” unless otherwise specified.

(Production of support)
An aluminum plate (material 1050, tempered H16) having a thickness of 0.3 mm was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water. This degreased aluminum plate was neutralized by dipping in a 10% aqueous hydrochloric acid solution maintained at 25 ° C. for 1 minute, and then washed with water. Next, the aluminum plate was subjected to electrolytic surface roughening with an alternating current for 60 seconds under conditions of 25 ° C. and a current density of 100 A / dm ^{2 in} a 0.3% by mass nitric acid aqueous solution, and then kept at 60 ° C. Desmutting treatment was performed for 10 seconds in a 5% aqueous sodium hydroxide solution. The surface-roughened aluminum plate subjected to desmut treatment was anodized in a 15% sulfuric acid solution at 25 ° C., a current density of 10 A / dm ² , and a voltage of 15 V for 1 minute, and further 3 mass% polyvinylphosphonic acid. A support was prepared by hydrophilizing at 75 ° C. At this time, the center line average roughness (Ra) of the surface was 0.65 μm.

(binder)
Acrylic resin (PA-1): Methacrylic acid / methyl methacrylate / ethyl methacrylate copolymer (15:30:55 methacrylic acid / methyl methacrylate / ethyl methacrylate) in 20.0% by weight of 2-butanone Solution containing mass ratio, Tg: 101 ° C., acid value: 98 mg KOH / g, molecular weight (Mw): 35,000) (Preparation of photosensitive lithographic printing plate material 1)
On the above support, the photopolymerization photosensitive layer coating solution shown in Table 1 below was applied with a wire bar so that it would be 1.6 g / m ² when dried, dried at 90 ° C. for 2 minutes, and then on the photosensitive layer. The oxygen barrier layer coating solution having the following composition is applied with an applicator so that the coating solution is 1.8 g / m ² when dried, and dried at 75 ° C. for 1.5 minutes to have an oxygen barrier layer on the photosensitive layer. A photosensitive lithographic printing plate sample 1 was prepared.

  (Photopolymerizable photosensitive layer coating solution 1)

(Oxygen barrier layer coating solution 1)
Polyvinyl alcohol (AL-06: manufactured by Nippon Synthetic Chemical Co., Ltd.) 89.5 parts polyvinyl pyrrolidone (Rubitec K-30: manufactured by BASF Corp.) 10.0 parts Surfactant (Surfinol 465: manufactured by Nissin Chemical Industry Co., Ltd.) 0. 5 parts Water 900 parts (Image formation, development processing)
The produced photosensitive lithographic printing plate material 1 uses a plate setter (MAKO4: manufactured by ECRM) equipped with a light source having a laser of 405 ± 5 nm and 60 mW, and the area ratio of the image part and the non-image part is 1 : Exposure energy so as to be 9: Image exposure with a resolution of 50 μJ / cm ² , 2400 dpi (dpi represents the number of dots per inch or 2.54 cm) (the exposure pattern is a 100% image area and 175 LPI) Halftone dots (98, 96, 94, 92, 90, 85, 80, 75, 70, 60, 50, 40, 30, 20, 15, 10, 8, 6, 5, 4, 3, 2, 1% Square dot)).

Next, a preheating portion that is heated so that the plate surface temperature is 105 to 130 ° C., a pre-water washing portion that removes the oxygen blocking layer before development, a developing portion filled with a developer having the following composition, and the developer attached to the plate surface are removed. 50 ml / m ² with a CTP automatic processor (PHW32-V: manufactured by Technigraph) equipped with a gum solution (GW-3: manufactured by Mitsubishi Chemical Co., Ltd., twice diluted) for protecting the washing section and the image area. Thus, the replenisher was replenished to obtain a lithographic printing plate. The plate surface temperature during actual plate making was 110 ° C. The time during which the photosensitive lithographic printing plate is in contact with the developer is defined as the development time, and the development time using the automatic processor is 25 seconds.

(Developer Examples)
A developer having the following composition was prepared.
Developer D. R. -1 (1000ml aqueous solution formulation)
The following compound P-1 3.0 mass%
Chelating agent (Dissolvin Na2-S manufactured by Akzo Novell) 0.5% by mass
Potassium hydroxide The remaining component of the addition amount to the following pH is water pH 12.1

  The photosensitive lithographic printing plate materials 2 to 25 were prepared in the same manner as the photosensitive lithographic printing plate material 1 with the sensitizing dye changed to D-2 to D-25.

  The photosensitive lithographic printing plate material 26 was prepared in the same manner as the photosensitive lithographic printing plate material 1 by changing the initiator to I-2 and the coinitiator to O-1.

  The photosensitive lithographic printing plate materials 27 to 62 were prepared in the same manner as the photosensitive lithographic printing plate material 1 by changing the monomers to L-2 to L-37.

[Linearity evaluation]
The halftone dots of the lithographic printing plate obtained by the development were measured with X-rite Dot (manufactured by X-rite).

  If the halftone dot area ratio after development becomes extremely larger than the exposure area, the halftone dots in the shadow area will be easily crushed, making adjustments difficult during plate-making and printing. The dot reproducibility is better as the dot area is larger than the exposure area and as close to the exposure area as possible.

  A dot area ratio of 50% or more and less than 60% was evaluated as ◯, 60% or more and less than 68% as Δ, 68% or more as less than 50% as ×.

[Evaluation of chemical resistance]
The lithographic printing plate obtained by the above development is coated with a printing press (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), printing ink (soybean oil ink “Naturalis 100” manufactured by Dainippon Ink & Chemicals, Inc.). Using a dampening solution (Tokyo ink Co., Ltd. H liquid SG-51 concentration 1.5%), wipe the image with a PS sponge showing an ultra plate cleaner every 500 sheets for 1 minute, and 3% halftone dot of printed matter The number of printed sheets when 3% halftone dots were missing more than half was used as an indicator of chemical resistance. The larger the number of printed sheets, the better the chemical resistance.

[Dirt on non-image area]
The lithographic printing plate obtained by the development treatment in the same manner as described above was coated with a printing machine (DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), coated paper, printing ink (soybean oil ink manufactured by Dainippon Ink & Chemicals, Inc.) Naturalis 100 ") and dampening water (Tokyo ink Co., Ltd. H liquid SG-51 density 1.5%). The non-image portion of the 1000th printed material was observed visually or with a magnifying glass to confirm the number of fine spots, and evaluated according to the following rank.

  When there were 3 or more fine spots of 100 microns or more in the range of 10 cm × 10 cm, it was inappropriate as a printed material and was evaluated as “x”.

  When 0 to 2 fine dot stains of 100 microns or more were observed in the range of 10 cm × 10 cm and 100 micron or less fine dot stains were observed, it was usable as a printed material and evaluated as Δ.

  Those without fine dot stains were excellent as printed materials and were evaluated as “Good”.

[Safelight evaluation]
Immediately after irradiating light of 240 lx which combined fluorescent lamp F40W / 35 (product made from GE) with V50 (product made from Encapslite), changing the irradiation time in the environment of 23 degreeC50%, the produced photosensitive material, Exposure energy: 50 μJ / cm ² , image exposure at a resolution of 2400 dpi (exposure pattern is 100% image area and 175 LPI dots (98, 96, 94, 92, 90, 85, 80, 75, 70, 60, 50, 40, 30, 20, 15, 10, 8, 6, 5, 4, 3, 2, 1% square dots)). Thereafter, development was carried out in the same manner as described above, and the halftone dot percentage of the halftone dot portion of the obtained lithographic printing plate image was measured with a halftone dot area measuring device (X-rite Dot model: manufactured by CCD5 Centrax Ltd).

  Based on a sample without safelight irradiation, the maximum time during which a halftone dot variation within ± 2.0% of the standard can be maintained was defined as a safelight allowable time.

  The results of the above various evaluations are summarized in Tables 2 to 4.

  As is apparent from Tables 2 to 4, the lithographic printing plate material according to the present invention is suitable for exposure with a laser beam having an emission wavelength in the range of 350 nm to 450 nm, has good safe light properties, and printing durability. It can be seen that the linearity and the printing performance are excellent.

Claims (4)

On a support having a hydrophilic surface, at least (A) a spectral sensitizer, (B) a polymerizable ethylenically unsaturated double bond-containing compound, (C) a hexaarylbiimidazole, (D) a thiol compound, and (E) In a photosensitive lithographic printing plate material having a photosensitive layer containing a photopolymerizable composition containing a polymer binder, the photopolymerizable composition has the general formula (1) as (A) a spectral sensitizer. And (B) an ethylenically unsaturated double bond-containing compound having a urethane bond in the molecule as a polymerizable ethylenically unsaturated double bond-containing compound. Sex lithographic printing plate material.

(In the formula, R _{1 to} R ₅ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms, or an optionally substituted alkyl group having 1 to 1 carbon atoms. 20 alkyl groups, C1-C12 alkoxy groups, or

Represents. R ₆ and R ₇ are each independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group that may have a substituent having 1 to 20 carbon atoms, an alkenyl group, or a substituent. Represents a good saturated hydrocarbon group, aromatic group or heteroaromatic group. R ₆ and R ₇ may be combined with an alkyl group having 1 to 20 carbon atoms, an alkenyl group, or an alkyl group or alkenyl group which may have a substituent to form a ring. R ₈ and R ₉ each represents an alkyl group having 2 to 10 carbon atoms, an alkyl group which may have a substituent having 2 to 10 carbon atoms, or an aryl group having 5 to 10 carbon atoms. Further, two adjacent R _{1 to} R ₉ , R ₁ and R ₂ , R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R ₅ , R ₆ and R ₇ , R ₃ and R ₈ ( R ₉ ), R ₅ and R ₉ (R ₈ ) may be combined with one or a combination of two or more to form a ring. ) The photosensitive lithographic printing plate material according to claim 1, wherein the compound containing an ethylenically unsaturated double bond having a urethane bond in the molecule is a compound represented by the general formula (2).

(Where Q is

Represents. R represents an alkyl group, a hydroxyalkyl group or an aryl group. R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or an alkoxyalkyl group, and R ₃ represents a hydrogen atom, a methyl group or an ethyl group. X ₁ represents a saturated hydrocarbon group, an aromatic hydrocarbon residue having 6 to 24 carbon atoms, or an alkyl group residue having an aromatic hydrocarbon group. X ₂ represents a saturated hydrocarbon residue having 2 to 8 carbon atoms. D ₁ and D ₂ are saturated hydrocarbon residues and may form a ring together with the nitrogen atom. In the case of forming a ring with a nitrogen atom, (b) of Q is included in the ring as a divalent or trivalent coupler. Z represents a hydrogen atom, a saturated hydrocarbon group having 1 to 3 carbon atoms, or a —C _k H _2k O—CONH (X ₁ —NHCOO) _b —X ₂ (—OOC—C (R ₃ ) ═CH ₂ ) group. . a represents an integer of 0 to 4, b represents 0 or 1, and k represents an integer of 1 to 12. m represents 2, 3 or 4 depending on the valence of Q, and n represents an integer of 1 to m. ) 3. The photosensitive lithographic printing plate material according to claim 1, comprising at least a photosensitive layer and an oxygen blocking layer containing polyvinyl alcohol as a main component on a support having a hydrophilic surface. The plate making which image-exposes the photosensitive lithographic printing plate material as described in any one of Claims 1-3 with the laser beam of the oscillation wavelength of 350-440 nm, heats to 100-130 degreeC, and develops it with alkaline aqueous solution after that. A method for making a photosensitive lithographic printing plate material, comprising developing with an alkaline developer having a pH of 11 to 12.6 which does not contain an organic solvent.