JP2005275230A - Photosensitive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared sensitive composition having stable chemical resistance and a large development latitude and providing a positive photosensitive lithographic printing plate for an infrared laser having high printing durability of dots. <P>SOLUTION: The infrared sensitive composition contains (A) a resin having a definite maleimide structure as a structural unit, (B) a surfactant having an HLB of <10, (C) a surfactant having an HLB of ≥10 and (D) an infrared absorbent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention mainly relates to a composition constituting a photosensitive layer used in a positive lithographic printing plate whose solubility in an alkaline aqueous solution is changed by infrared exposure, and more specifically, an infrared laser beam is generated based on a digital signal from a computer or the like. The present invention relates to a photosensitive composition that can be used for a positive lithographic printing plate capable of direct plate making by scanning, so-called direct plate making.

  In recent years, the development of lasers has been remarkable. In particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared region to the infrared region have been increasing in output and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.

  A positive lithographic printing plate material for an infrared laser, which uses an infrared laser having a light emitting region in the above infrared region as an exposure light source, comprises an alkaline aqueous solution-soluble binder resin and an IR dye that absorbs light and generates heat. It is a lithographic printing plate material that is an essential component. When the infrared laser is exposed to the infrared laser positive lithographic printing plate material, an IR dye or the like in the infrared laser positive lithographic printing plate material is bonded to the binder resin in a non-exposed portion (image portion). The interaction acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin. On the other hand, in the exposed area (non-image area), the IR dye or the like absorbs light and generates heat, so that the interaction between the IR dye or the like and the binder resin is weakened. Therefore, at the time of development, the exposed portion (non-image portion) is dissolved in the alkaline developer, and a lithographic printing plate is formed. However, in such a positive lithographic printing plate material for infrared laser, compared with a positive lithographic printing plate material made by UV exposure, a resin having high solubility in an alkaline developer must be used as a binder resin. Therefore, since the chemical resistance is low and the resistance to the plate cleaner used when the ink adheres during printing is low, the photosensitive composition is eluted when the plate surface is wiped with the cleaner.

For this reason, in order to improve chemical resistance, Patent Document 1 and the like describe a photosensitive composition comprising a photosensitive layer containing a polymer having a specific structural unit, and the chemical resistance described above can be improved to some extent. Has been reported. However, such positive photosensitive lithographic printing plates for infrared lasers have a problem that the printing durability of small halftone dots at the highlight portion is particularly poor.
Further, the development stability (development latitude) depending on the use conditions is insufficient, and in particular, there is a problem that excessive development with a high concentration developer occurs.

US Pat. No. 6,475,692

  The object of the present invention is to overcome the drawbacks of the above-mentioned conventional techniques, and to provide a positive lithographic printing plate precursor for infrared laser having a certain chemical resistance, a wide development latitude, and a high small dot printing durability. It is to provide an infrared-sensitive composition.

一般式（１）中、Ｒ₁〜Ｒ₃は任意の置換基を表す。 As a result of diligent research, the present inventor has found that a photosensitive composition contains a polymer having a special structural unit and a surfactant having an HLB defined in a certain range, thereby achieving the above-described object. I found.
Specifically, (A) a resin having a structural unit represented by the general formula (1), (B) a surfactant of less than HLB 10, (C) a surfactant of HLB 10 or more, and (D) an infrared absorber, It is an infrared sensitive photosensitive composition containing this.

In general formula (1), R < ₁ > -R < ₃ > represents arbitrary substituents.

  Although the operation of the present invention is not clear, it is presumed as follows. Chemical resistance and strength (hardness) are improved by the properties of the polymer having the structural unit of the general formula (1) introduced. Further, by combining with two kinds of surfactants that define HLB, the effect of improving the small dot printing durability can be obtained.

  With the photosensitive composition of the present invention, a photosensitive lithographic printing plate having a certain chemical resistance, a wide development latitude, and excellent small-point printing durability can be obtained.

一般式（１）中、Ｒ₁〜Ｒ₃は任意の置換基を表す。
以下、本発明の感光性組成物について詳細に説明する。 The photosensitive composition of the present invention comprises (A) a resin having a structural unit represented by the general formula (1) (hereinafter, sometimes referred to as a specific structural unit-containing polymer), and (B) a surfactant having an HLB less than 10. (C) HLB10 or more surfactant and (D) infrared absorber.

In general formula (1), R < ₁ > -R < ₃ > represents arbitrary substituents.
Hereinafter, the photosensitive composition of the present invention will be described in detail.

[(A) Specific structural unit-containing polymer]
The specific structural unit-containing polymer specifically refers to a polymer having a structural unit represented by the following general formula (1).

In the general formula (1), R ₁ represents an arbitrary substituent. R ₁ is preferably hydrogen; unsubstituted or optionally substituted (C ₆ -C ₁₂ ) aryl; unsubstituted or optionally substituted (C ₁ -C ₁₂ ) alkyl; unsubstituted or optionally substituted (C ₃ -C ₁₀ ) cycloalkyl; an unsubstituted or optionally substituted arylsulfonamido group; or an unsubstituted or optionally substituted sulfonamido group. The optional substituent in each group is preferably one or more substituents selected from halogen, alkyl, —NO ₂ and —OH. Particularly preferably R ₁ is hydrogen, phenyl, cyclohexyl or hydroxyphenyl.

In the general formula (1), R ₂ and R ₃ also represent an arbitrary substituent. Preferably, R ₂ and R ₃ are independently hydrogen, halogen, (C ₁ -C ₄ ) Selected from the group consisting of alkyl and phenyl. Particularly preferably, R ₂ and R ₃ are both hydrogen.

  The (A) specific structural unit-containing polymer may be a homopolymer of a polymerizable monomer containing the structural unit represented by the general formula (1). It may be a copolymer with a compound having a saturated bond and not having the structural unit represented by the general formula (1). In this case, the copolymer may have any structure such as a block body, a random body, or a graft body, and is a compound having a structural unit represented by the general formula (1) with respect to the copolymer. As a copolymerization ratio, 10-90 mol% is preferable, 20-70 mol% is more preferable, 35-60 mol% is especially preferable.

  Examples of the compound having one or more polymerizable unsaturated bonds and not having the structural unit represented by the general formula (1) include methyl acrylate, ethyl acrylate, propyl acrylate, and acrylic acid. Butyl, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate Acrylates such as glycidyl acrylate, benzyl acrylate, methoxybenzyl acrylate and tetrahydroacrylate: aryl acrylates such as phenyl acrylate and furfuryl acrylate: methyl Tacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, amyl methacrylate hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3-hydroxy Methacrylic acid esters such as propyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate: aryl methacrylates such as phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate G: Acrylamide or derivatives thereof include N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, Nt-butylacrylamide, N-heptylacrylamide, N-octylacrylamide, N-cyclohexylacrylamide N-alkylacrylamides such as N-benzylacrylamide: N-phenylacrylamide, N-tolylacrylamide, N-nitrophenylacrylamide, N-naphthylacrylamide, N-arylacrylamides such as N-hydroxyphenylacrylamide: N, N -Dimethylacrylamide, N, N-diethylacrylamide, N, N-dibutylacrylamide, N, N-dibutylacrylamide, N, N-diisobuty N, N-dialkylacrylamides such as acrylamide, N, N-diethylhexylacrylamide, N, N-dicyclohexylacrylamide: N-methyl-N-phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, N-2-acetamide N, N-arylacrylamides such as ethyl-N-acetylacrylamide: methacrylamide or derivatives thereof include N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, Nt N-alkylmethacrylamides such as N-butylmethacrylamide, N-ethylhexylmethacrylamide, N-hydroxyethylmethacrylamide, N-cyclohexylmethacrylamide: N-aryl methacrylamides such as chloramide and N-naphthyl methacrylamide: N, N-dialkyl methacrylamides such as N, N-diethyl methacrylamide, N, N-dipropyl methacrylamide and N, N-dibutyl methacrylamide : N, N-diarylmethacrylamides such as N, N-diphenylmethacrylamide: N-hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N-phenylmethacrylamide Methacrylamide derivatives: Allyl compounds such as allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl palmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, allyloxyethanol: hex Sil vinyl ether, octyl vinyl ether, dodecyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethyl Aminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl Vinyl ethers such as ether: vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl methoxyacetate, vinyl butoxy acetate, vinyl phenyl acetate, vinyl acetoacetate Vinyl esters such as vinyl lactate, vinyl-β-phenylbutyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate: methyl styrene, dimethyl styrene, Trimethyl styrene, ethyl styrene, diethyl styrene, isopropyl styrene, butyl styrene, hexyl styrene, cyclohexyl styrene, Dodecylstyrene, benzylstyrene, chloromethylstyrene, trifluoromethylstyrene, ethoxymethylstyrene, acetoxymethylstyrene, methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene, chlorostyrene, dichlorostyrene, trichlorostyrene, tetrachlorostyrene , Such as pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro-3-trifluoromethylstyrene: butyl crotonate, hexyl crotonate Crotonic acid esters such as crotonic acid and glycerin monocrotonate: Dialkyl itaconate such as dimethyl itaconate, diethyl itaconate and dibutyl itaconate S: dimethyl maleate: Other, N- vinylpyrrolidone, N- vinyl pyridine, acrylonitrile, methacrylonitrile, and the like. These compounds may be used individually by 1 type, and may use 2 or more types together.

  Of these compounds, (meth) acrylic acid esters, (meth) acrylamides, and (meth) acrylonitriles are preferable.

  In the present specification, the description called (meth) acrylate means acrylate and methacrylate, and the description called (meth) acrylic acid means acrylic acid and methacrylic acid. The description referred to as (meth) acrylonitrile means acrylonitrile and methacrylonitrile, and (meth) acrylamide means acrylamide and methacrylamide.

  The molecular weight of the copolymer is preferably 500 to 1,000,000, particularly preferably 2,000 to 250,000 in terms of weight average molecular weight.

[(B) Surfactant less than HLB10, (C) Surfactant greater than HLB10]
In the photosensitive composition according to the present invention, a “surfactant having an HLB less than 10” (hereinafter sometimes referred to as a lipophilic surfactant) and a “surfactant having an HLB of 10 or more” (hereinafter referred to as a hydrophilic interface). It may be necessary to contain an active agent). Preferably, the HLB range of the new oily surfactant is 3 to 9, more preferably 5 to 8.5. Moreover, as a range of HLB of a hydrophilic surfactant, Preferably, HLB is 11-18, More preferably, it is 12-16.
Here, HLB means hydrophilicity-lipophilic balance (hydrophilic-lipophilic balance), and the smaller the number, the stronger the lipophilicity, and the larger the number, the stronger the fresh water.

  As the surfactant used in the present invention, any of anionic, cationic, nonionic, and the like can be used. Particularly preferable examples include nonionic surfactants, such as ether type, ester type, Examples include amino ether type, ether ester type, and alkanolamide type. Specifically, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene / oxypropylene block copolymer, polyethylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol Fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, alkyl alkanolamide, polyoxyethylene alkylamino ether, pentaerythritol fatty acid ester, polyethylene glycol, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene Polyoxypropylene ether derivative, polyoxyp Pyreneglyceryl ether, methoxypolyethylene glycol, glycerol borate fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene glycerol borate fatty acid ester, polyoxyethylene fatty acid alkanolamide, polyglycerin fatty acid ester, propylene glycol fatty acid ester, polyoxyethylene sorbit Examples include fatty acid esters, polyoxyethylene phytosterol, polyoxyethylene phytostanol, polyoxyethylene vegetable oil, polyoxyethylene lanolin, polyoxyethylene lanolin alcohol, polyoxyethylene beeswax derivatives, and polyoxyethylene alkylphenyl formaldehyde condensates. Among these, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene / polyoxypropylene block polymer, polyoxyethylene sorbit fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol, polyoxyethylene are preferable. Examples include glycerin fatty acid ester, polyethylene glycol fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid ester, pentaerythritol fatty acid ester, propylene glycol fatty acid ester, and polyglycerin fatty acid ester.

  More preferred are polyoxyethylene alkyl ether, polyoxyethylene sorbit fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyglycerin fatty acid ester, polyethylene glycol, polyethylene glycol fatty acid ester, especially polyoxyethylene sorbit fatty acid ester, polyethylene glycol fatty acid ester An ester is preferred. Even if the above-mentioned surfactants are of the same type, for example, the HLB differs depending on the number of repeating oxyethylene repeating units. Therefore, select those having an HLB of less than 10 and those having an HLB of 10 or more. Combined. For example, as a compound of less than HLB10, tetraoleic acid polyoxyethylene sorbite, distearic acid sorbitan ester, distearic acid polyethylene glycol (300) ester, oleyl polyoxyethylene (2) ether, and the like can be mentioned. Examples include, but are not limited to, polyethylene stearate polyethylene glycol (400) ester, tridodecyl polyoxyethylene (6) ether, trioleic acid polyoxyethylene (20) sorbitan ester, and the like.

  In addition to the above, as described in JP-A-62-251740 and JP-A-3-208514, in order to widen the stability of processing with respect to development conditions or to improve the coating property. Nonionic surfactants, amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane-based compounds as described in EP950517, JP-A-11 A fluorine-containing monomer copolymer as described in JP-A-288093 and a fluorine-based surfactant as described in JP-A-62-170950 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.). The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany. These surfactants are similarly used in combination with those having an HLB of less than 10 and those having an HLB of 10 or more.

  In the photosensitive composition according to the present invention, if the content of the surfactant of less than HLB 10 is too small, the development latitude tends to be small, and if it is too large, the development latitude tends to be small. Preferably it is 0.5 to 20%, More preferably, it is 1 to 10% or more, Most preferably, it is 2 to 8%. Moreover, if the content of the surfactant of HLB10 or higher is too small, a sufficient development preventing effect (film slipping preventing effect) of the unexposed area (image area) cannot be obtained, and if it is too large, the development latitude tends to be small. Therefore, it is preferably 0.05 to 15% or more, more preferably 0.1 to 10% or more, and particularly preferably 0.15 to 8%. The content ratio of low HLB, that is, lipophilic surfactant and high HLB, that is, hydrophilic surfactant is preferably 40: 1 to 1:10, more preferably 30: 1 to 1: 5. Yes, particularly preferably 20: 1 to 1: 1.

[(D) Infrared absorber]
The infrared absorber contained in the photosensitive composition according to the present invention has a light absorption region in the infrared region of 700 nm or more, preferably 750 to 1200 nm, and has a light / heat conversion ability by light in this wavelength region. Refers to the substance to be expressed. Specifically, various dyes or pigments that absorb light in the wavelength range and generate heat can be used.

  As the dye, commercially available dyes, for example, known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, Examples thereof include oxonol dyes, diimonium dyes, aminium dyes, and croconium dyes.

  Preferred dyes include, for example, cyanine dyes described in JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59- 48187, JP-A 59-73996, JP-A 60-52940, JP-A 60-63744, etc., naphthoquinone dyes, JP-A 58-112792, etc. And cyanine dyes described in British Patent 434,875.

Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924 Trimethine thiapyrylium salts described in JP-A Nos. 57-142645 (US Pat. No. 4,327,169), JP-A Nos. 58-181051, 58-220143, 59-41363, 59- 84248, 59-84249, 59-146063, 59-146061, pyrylium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 And the pyrylium compounds disclosed in JP-B-5-13514 and JP-A-5-19702 are also preferably used. .
Another example of a preferable dye is a near-infrared absorbing dye described in U.S. Pat. No. 4,756,993 as formulas (I) and (II).

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Further, the dyes represented by the following general formulas (a) to (e) are preferable because they are excellent in photothermal conversion efficiency. Particularly, the cyanine dye represented by the following general formula (a) is the photosensitive lithographic printing plate according to the present invention. Is most preferable because it gives high interaction with the alkali-soluble resin and is excellent in stability and economy.

In formula (a), X ¹ represents a hydrogen atom, a halogen atom, -NPh _2, X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a carbon atom having 1 to 12 carbon atoms including a hetero atom. Indicates a hydrogen group. Here, the hetero atom represents N, S, O, a halogen atom, or Se.

In the above formula, Xa ^- has Za described later ^- is defined as for, Ra represents a hydrogen atom, an alkyl group, ant - represents a group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom . R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, if the sulfo group in any of R ¹ to R ⁸ is substituted, Za ^- is not necessary. Preferred Za ⁻ is halogen ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, and sulfonate ion, particularly preferably perchloric acid, from the storage stability of the photosensitive layer coating solution. Ions, hexafluorophosphate ions, and aryl sulfonate ions.

Specific examples of the cyanine dye represented by formula (a) that can be suitably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A-2001-133969. And those described in paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

Next, compounds represented by formula (b) are shown.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents are bonded to each other to form a ring structure. Also good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Ni ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, This represents a substituent selected from an oxy group or an amino group, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in the general formula (b), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. From the viewpoint of the effect.

  Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.

Next, compounds represented by the general formula (c) are shown.

In the general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group. Represents a thio group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a) ^- it is synonymous.

In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

Next, compounds represented by the general formula (d) are shown.

In the general formula (d), R ²⁹ to R ³¹ each independently represents a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represents an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ A ring may be bonded to each other, and when there are a plurality of R ³³ or R ³⁴ , R ³³ or R ³⁴ may be bonded to each other to form a ring. X ² and X ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group, and at least one of X ² and X ³ represents a hydrogen atom or an alkyl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ⁻ represents a counter anion and has the same meaning as Za ⁻ in the general formula (a).

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

Next, compounds represented by the general formula (e) are shown.

In the general formula (e), R ^{35 to} R ⁵⁰ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxyl group which may have a substituent. , A carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, an amino group, and an onium salt structure. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein are IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements can be mentioned, among which copper, magnesium, iron, zinc, cobalt, aluminum, titanium, and vanadium are preferable.

  In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

  Examples of the pigment include commercially available pigments or color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), and The pigments described in “Printing Ink Technology” published by CMC (published in 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and polymer-bonded pigments. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isotopic pigments Indolinone pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, and carbon black can be used.

  These pigments may be used without surface treatment or may be used after surface treatment. As the surface treatment method, a method of surface coating of resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate) to the pigment surface Etc. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the particle diameter of the pigment is less than 0.01 μm, it is not preferable from the viewpoint of stability of the dispersion in the coating solution, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the photosensitive layer.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Dispersers include ultrasonic dispersers, sand mills, attritors, par mills, super mills, ball mills, impellers, desperzers, KD mills, colloid mills, Dynatrons, three-rollers Lumil, pressure kneader and the like. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  These pigments or dyes are 0.01 to 50% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.5 to 10% by weight, based on the total solids constituting the photosensitive layer. In this case, it is particularly preferably added at a ratio of 0.1 to 10% by weight. When the amount of pigment or dye added is less than 0.01% by weight, the sensitivity tends to be low. When the amount exceeds 50% by weight, the uniformity of the photosensitive layer and the photosensitive layer There is a risk of adversely affecting durability.

〔Layer structure〕
The photosensitive layer of the photosensitive lithographic printing plate using the photosensitive composition of the present invention can be used in any of a single layer structure, a phase separation structure, and a multilayer structure.
As the monolayer type photosensitive layer, for example, the photosensitive layer described in JP-A-7-285275, WO 97/39894 pamphlet, and as the phase separation type photosensitive layer, for example, the photosensitive layer described in JP-A-11-44956, Examples of the multi-layer type photosensitive layer include those described in JP-A-11-218914, US Pat. No. 6,352,812 B1, US Pat. No. 6,352,811 B1, US Pat. No. 6,358,669 B1, US Pat. Although it can be used as a layer, it is not limited to these.
In the case of a multilayer structure, the components (A) to (D) relating to the photosensitive composition of the present invention are not limited to the lower layer and the uppermost layer, and may be contained in any layer. (A) and (D) components, a photosensitive layer containing the components (B) and (C) in the uppermost layer, or a photosensitive layer containing the components (A) to (D) only in the uppermost layer. In addition, Preferably, although the form of having (B), (C) (D) component in an uppermost layer and (A) component in a lower layer is mentioned, it is not limited to these.

[Other ingredients]
Various additives can be further added to the photosensitive composition according to the present invention as necessary.
For example, in addition to (A) an aqueous alkali-soluble resin other than a resin having a specific structural unit, another alkali-soluble resin can be contained in the photosensitive composition as necessary. In this case, the other alkali-soluble resin is not particularly limited, but a novolac resin is preferable.

  Examples of the novolak resin include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p -Any of mixing, m- / o-mixing and o- / p-mixing.) Mixed formaldehyde resins are mentioned. These may be used alone or in combination of two or more.

  These novolak resins preferably have a weight average molecular weight of 1,500 or more and a number average molecular weight of 300 or more. More preferably, the weight average molecular weight is 3,000 to 300,000, the number average molecular weight is 500 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

Preferable alkali-soluble resins other than the novolak resin include those having the acidic groups listed in the following (1) to (6) in the main chain and / or side chain of the polymer.
(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R)
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR, —SO ₂ NHSO ₂ R, —CONHSO ₂ R]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )
In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent.

  Among the alkali-soluble resins having an acidic group selected from the above (1) to (6), an alkali-soluble resin having (1) a phenol group, (2) a sulfonamide group, and (3) an active imide group is preferable, An alkali-soluble resin having (1) a phenol group or (2) a sulfonamide group is most preferred from the viewpoint of sufficiently ensuring solubility in an alkaline developer, development latitude, and film strength.

As alkali-soluble resin which has an acidic group chosen from said (1)-(6), the following can be mentioned, for example.
(1) Examples of the alkali-soluble resin having a phenol group include a condensation polymer of phenol and formaldehyde, a condensation polymer of m-cresol and formaldehyde, a condensation polymer of p-cresol and formaldehyde, m− / p. A novolak resin such as a condensation polymer of mixed cresol and formaldehyde, a condensation polymer of phenol and cresol (any of m-, p-, or m- / p-mixing) and formaldehyde, and pyrogallol and acetone Can be mentioned. Furthermore, the copolymer which copolymerized the compound which has a phenol group in a side chain can also be mentioned. Alternatively, a copolymer obtained by copolymerizing a compound having a phenol group in the side chain can also be used.

  Examples of the compound having a phenol group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenol group.

(2) As an alkali-soluble resin having a sulfonamide group, for example, a polymer composed of a minimum constituent unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Among them, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule is preferable. For example, the following general formula (i) to general formula ( and a compound represented by v).

[Wherein, X ¹ and X ² each independently represent —O— or —NR ⁷ . R ¹ and R ⁴ each independently represents a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , and R ¹⁶ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group, or aralkylene group that may have a substituent. . R ³ , R ⁷ and R ¹³ each independently represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ¹⁷ each independently represents a C 1-12 alkyl group, cycloalkyl group, aryl group or aralkyl group which may have a substituent. R ⁸ , R ¹⁰ and R ¹⁴ each independently represent a hydrogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each independently represent a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ¹ and Y ² each independently represent a single bond or CO. ]

  Among the compounds represented by the general formula (i) to the general formula (v), in the multilayer photosensitive lithographic printing plate prepared using the photosensitive composition of the present invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

(3) As an alkali-soluble resin having an active imide group, for example, a polymer composed of a minimum constituent unit derived from a compound having an active imide group as a main constituent can be mentioned. Examples of the compound as described above include compounds each having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule.

  Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) As an alkali-soluble resin having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.
(5) As the alkali-soluble polymer having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and a polymerizable unsaturated group in the molecule is a main structural unit. Can be mentioned.
(6) As an alkali-soluble resin having a phosphate group, for example, a minimum structural unit derived from a compound having at least one phosphate group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

  The minimum structural unit having an acidic group selected from the above (1) to (6) that constitutes the alkali-soluble resin used in the uppermost layer of the photosensitive lithographic printing plate is not particularly limited to one type, and is the same Two or more minimum structural units having an acidic group, or two or more minimum structural units having different acidic groups copolymerized may be used.

  The copolymer preferably contains 10 mol% or more of a compound having an acidic group selected from (1) to (6) to be copolymerized, and is contained in an amount of 20 mol% or more. Those are more preferred. If it is less than 10 mol%, the development latitude tends to be insufficiently improved.

  Examples of the monomer component to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the monomers listed in (m1) to (m12) below. However, it is not limited to these.

(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.
(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  The alkali-soluble resin in the present invention is preferably a polymerizable monomer having a phenolic hydroxyl group or a homopolymer or copolymer of a polymerizable monomer having an active imide group, and particularly m-aminosulfonylphenyl methacrylate, N- ( A homopolymer or copolymer of a polymerizable monomer having a sulfonamide group such as p-aminosulfonylphenyl) methacrylamide or N- (p-aminosulfonylphenyl) acrylamide is preferred. The weight average molecular weight is preferably 2,000 or more and the number average molecular weight is 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. . In the present invention, when the alkali-soluble resin is a resin such as a phenol formaldehyde resin or a cresol aldehyde resin, the weight average molecular weight is 500 to 20,000, and the number average molecular weight is preferably 200 to 10,000. .

  These alkali-soluble resins may be used alone or in combination of two or more, and are 30 to 99% by weight, preferably 40 to 95% by weight, particularly preferably 50 to 90% in the total solid content of the heat-sensitive layer. Used in an amount of addition by weight. When the addition amount of the alkali-soluble resin is less than 30% by weight, the durability of the heat-sensitive layer deteriorates. When the addition amount exceeds 99% by weight, “(A) an alkaline aqueous solution-soluble resin having a urea bond in the side chain” "Is reduced, the chemical resistance is lowered, which is not preferable.

  In addition, in order to adjust the solubility of the photosensitive layer, when other onium salts, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, polyfunctional amine compounds, etc. are added, development of an alkali water-soluble polymer (alkali-soluble resin) is performed. It is preferable to add a so-called dissolution inhibitor that improves the dissolution inhibition function in the liquid, and among them, onium salts, o-quinonediazide compounds, sulfonic acid alkyl esters and the like are thermally decomposable, and in a state where they are not decomposed, alkali-soluble resins It is preferable to use a substance that substantially lowers the solubility in terms of improving the solubility of the image area in the developer.

  Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 5,041,358, No. 4,491,628, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

  Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. As the quaternary ammonium salt, quaternary ammonium salts represented by (1) to (10) in [Chemical Formula 5] and [Chemical Formula 6] described in JP-A-2002-229186 are preferable.

  The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. The compounds described in pages 339 to 352 of “Light-sensitive systems” by John Coley (John Wiley & Sons. Inc.) can be used, and in particular, o-quinonediazide reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. The sulfonic acid esters or sulfonic acid amides are preferred. Further, benzoquinone (1,2) -diazidosulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in US Pat. Nos. 3,046,120 and 3,188,210 Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

  The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, particularly preferably the total solid content of the photosensitive layer. Is in the range of 1-2% by weight. These compounds can be used alone, but may be used as a mixture of several kinds.

  The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

  Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.

  Moreover, as an additive used for the uppermost layer of the photosensitive lithographic printing plate, cyclic acid anhydrides, phenols, and organic acids can be used in combination for the purpose of improving sensitivity. In addition, surfactants, image colorants, and plasticizers described later can also be used in the photosensitive composition of the present invention.

Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, Maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 “-Trihydroxytriphenylmethane, 4,4 ′, 3”, 4 ”-tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.
The proportion of the cyclic acid anhydride, phenols, and organic acids in the photosensitive layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by mass.

  In addition to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group described in JP-A-8-276558, and the inventors previously proposed. A crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 can be appropriately added depending on the purpose.

Further, a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644, and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the photosensitive layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the photosensitive layer.

  Furthermore, a plasticizer is added to the uppermost layer of the photosensitive lithographic printing plate, if necessary, in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

(Coating solvent and coating method)
The photosensitive composition of the present invention can be prepared by dissolving in a solvent and coating on a suitable support. Further, depending on the purpose, a protective layer, a resin intermediate layer, a backcoat layer and the like, which will be described later, can be formed in the same manner.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.

The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.
In addition, the coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but in general, the coating amount after drying is preferably 0.5 to 5.0 mg / m ² , An amount of 0.6 to 2.0 mg / m ² is more preferable.

  Various methods can be used to apply the image recording layer (photosensitive layer) coating solution. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating. , Roll coating and the like. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the photosensitive film deteriorate.

[Create lithographic printing plate]
(Support)
The support used in the photosensitive lithographic printing plate produced from the photosensitive composition of the present invention is a dimensionally stable plate-like material that satisfies the required physical properties such as strength and flexibility. If it is, there will be no restriction | limiting in particular, For example, paper, paper (for example, polyethylene, polypropylene, polystyrene, etc.) laminated, metal plate (for example, aluminum, zinc, copper, etc.), plastic film (for example, cellulose diacetate) , Cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic on which the above metals are laminated or vapor-deposited Such as film .

As the support applicable to the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. 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 at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution 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, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, 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. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. 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, phosphoric 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 treatment conditions for anodization vary depending on the electrolyte used, and thus 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 / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image part of the lithographic printing plate is easily damaged, and the ink adheres to the damaged part during printing. So-called “scratch dirt” is likely to occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

(Undercoat layer)
As described above, the photosensitive composition of the present invention can be coated on a support to form a photosensitive layer to produce a photosensitive lithographic printing plate, but if necessary, between the support and the lower layer. An undercoat layer can be provided. By providing this undercoat layer, the undercoat layer between the support and the photosensitive layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, there is an advantage that high sensitivity can be achieved. Further, since the photosensitive layer according to the present invention is located on the exposed surface or in the vicinity thereof even when the undercoat layer is provided, the sensitivity to the infrared laser is favorably maintained.

  In the unexposed area, the photosensitive layer itself that is impermeable to the alkali developer functions as a protective layer for the undercoat layer, so that the development stability is good and the image is excellent in discrimination. In the exposed area, the components of the photosensitive layer whose dissolution-inhibiting ability has been released are quickly dissolved and dispersed in the developer. Since the undercoat layer itself, which is adjacent to the support, is made of an alkali-soluble polymer, it has good solubility in a developer, for example, even when a developer with reduced activity is used. It is considered that this undercoat layer is useful because it dissolves rapidly without the formation of a film and the like and contributes to the improvement of developability.

  Various organic compounds are used as the primer layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent Organic phosphonic acids such as naphthyl phosphonic acid, alkyl phosphonic acid, glycero phosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, phenyl phosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

  Furthermore, an undercoat layer containing at least one compound selected from the group of organic polymer compounds having a structural unit represented by the following formula is also preferred.

R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group, and R ¹² and R ¹³ each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, —OR ^14. , -COOR ¹⁵ , -CONHR ¹⁶ , -COR ¹⁷ or -CN, or R ¹² and R ¹³ may be bonded to form a ring, and R ^{14 to} R ¹⁷ are each independently an alkyl group or Represents an aryl group, X represents a hydrogen atom, a metal atom, or NR ¹⁸ R ¹⁹ R ²⁰ R ²¹ , and R ^{18 to} R ²¹ each independently represent a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl. Represents a group, or R ¹⁸ and R ¹⁹ may combine to form a ring, and m represents an integer of 1 to 3.

Moreover, as a suitable undercoat layer component in the present invention, there can be mentioned a polymer compound having a component having an acid group and a component having an onium group, as described in JP-A No. 2000-241962. Specific examples include a copolymer of a monomer having an acid group and a monomer having an onium group. An acid group having an acid dissociation index (pKa) of 7 or more is preferred as the acid group, and more preferably —COOH, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , — CONHSO ₂ — or —SO ₂ NHSO ₂ —, particularly preferably —COOH. Specific examples of the monomer having an acid group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, itaconic acid, maleic acid, maleic anhydride, and styrene having the acid group. Preferred as the onium salt is an onium group composed of Group V or Group VI atoms, more preferably an onium salt composed of nitrogen, phosphorus or sulfur atoms, and particularly preferably an onium salt composed of nitrogen atoms. Salt. Specific examples of the monomer having an onium salt include styrene having a substituent containing an onium group such as a methacrylate having an ammonium group in the side chain, a methacrylamide, a substituent containing an onium group such as a quaternary ammonium group, and the like. It is done.
Furthermore, compounds such as those described in JP-A-2000-108538 can be used as necessary.

These undercoat layers can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution in which the above organic compound is dissolved in the above organic solvent or a mixed solvent thereof to adsorb the above compound, then washed with water or the like and dried to provide an undercoat layer. In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material. The coating amount of the undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. Moreover, even if it is larger than 200 mg / m ^2, it is the same.

  The lithographic printing plate according to the present invention forms an image by heat. Specifically, direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, infrared lamp exposure, and the like are used, but a semiconductor that emits infrared light having a wavelength of 700 to 1200 nm. Exposure by a solid high-power infrared laser such as a laser or a YAG laser is suitable.

The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy applied to the recording material is preferably 10 to 500 mJ / cm ² .

  The developer that can be applied to the lithographic printing plate prepared from the photosensitive composition of the present invention has a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. It is a liquid. A conventionally known alkaline aqueous solution can be used as the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base or containing an alkali silicate by mixing a silicon compound with a base. Another more preferable developer, which is an aqueous solution called “silicate developer” having a pH of 12 or more, does not contain an alkali silicate, and contains a non-reducing sugar (an organic compound having a buffering action) and a base. Silicate developer ".

In the former, the aqueous solution of alkali metal silicate is represented by the ratio of silicon oxide SiO ₂ which is a component of silicate to alkali metal oxide M ₂ O (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]. ) And the density, the developing property can be adjusted. For example, as disclosed in JP-A-54-62004, the molar ratio of SiO ₂ / Na ₂ O is 1.0 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5), and an aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4 mass% is disclosed in JP-B-57-7427. As described, [SiO ₂ ] / [M] is 0.5 to 0.75 (ie, [SiO ₂ ] / [M ₂ O] is 1.0 to 1.5), and SiO ₂ The developer is based on gram atoms of all alkali metals present in the developer. A manner containing potassium at least 20%, aqueous solution of an alkali metal silicate is preferably used.

  In addition, a so-called “non-silicate developer” that does not contain an alkali silicate and contains a non-reducing sugar and a base is applied to the development of a lithographic printing plate material prepared from the photosensitive composition of the present invention. Is more preferable. When the lithographic printing plate material is developed using this developer, the surface of the photosensitive layer is not deteriorated and the inking property of the photosensitive layer can be maintained in a good state. In addition, the lithographic printing plate material generally has a narrow development latitude and a large change in the image line width due to the developer pH, but the non-silicate developer contains a non-reducing sugar having a buffering property that suppresses fluctuations in pH. Therefore, it is more advantageous than the case where a developing processing solution containing silicate is used. Furthermore, since non-reducing sugars are less likely to contaminate conductivity sensors, pH sensors and the like for controlling liquid activity compared to silicates, non-silicate developers are advantageous in this respect as well. Further, the effect of improving discrimination is remarkable. This is presumably because the contact (penetration) with the developer which is important in the present invention is mild, and the difference between the exposed and unexposed areas is likely to occur.

  The non-reducing sugar is a saccharide that does not have a free aldehyde group or a ketone group and does not exhibit reducibility, and is a trehalose-type oligosaccharide in which reducing groups are bonded to each other, or a glycoside in which a reducing group and a non-saccharide are bonded to each other. And sugar alcohols reduced by hydrogenation of saccharides and sugars, both of which can be suitably used in the present invention. In the present invention, non-reducing sugars described in JP-A-8-305039 can be preferably used.

  Examples of the trehalose type oligosaccharides include saccharose and trehalose. Examples of the glycoside include alkyl glycosides, phenol glycosides, and mustard oil glycosides. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, zulsiit, allozulcit and the like. . Further, maltitol hydrogenated to disaccharide maltose, reduced form obtained by hydrogenation of oligosaccharide (reduced water candy), and the like are preferable. Among these non-reducing sugars, trehalose-type oligosaccharides and sugar alcohols are preferable, and among them, D-sorbitol, saccharose, reduced syrup, etc. are preferable in that they have a buffering action in an appropriate pH region and are inexpensive.

  These non-reducing sugars may be used alone or in combination of two or more. The content of the non-reducing sugar in the non-silicate developer is preferably 0.1 to 30% by mass, and more preferably 1 to 20% by mass. If the content is less than 0.1% by mass, a sufficient buffering effect tends to be not obtained, and if it exceeds 30% by mass, it is difficult to achieve high concentration and the cost tends to increase.

  Examples of the base used in combination with the non-reducing sugar include conventionally known alkali agents such as inorganic alkali agents and organic alkali agents. Examples of the inorganic alkaline agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, Examples thereof include sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate.

  Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanol. Examples include amine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine.

  The said base may be used individually by 1 type, and may use 2 or more types together. Among these bases, sodium hydroxide and potassium hydroxide are preferable. In the present invention, as the non-silicate developer, a non-reducing sugar alkali metal salt as a main component can be used instead of the non-reducing sugar and the base.

  In addition, an alkaline buffer composed of a weak acid other than the non-reducing sugar and a strong base can be used in combination with the non-silicate developer. The weak acid preferably has a dissociation constant (pKa) of 10.0 to 13.2, and can be selected from, for example, those described in Ionization Constants of Organic Acidsin Aqueous Solution published by Pergmon Press.

  Specifically, alcohols such as 2,2,3,3-tetrafluoropropanol-1, trifluoroethanol and trichloroethanol, pyridine-2-aldehyde (, aldehydes such as pyridine-4-aldehyde (and the like) , Salicylic acid, 3-hydroxy-2-naphthoic acid, catechol, gallic acid, sulfosalicylic acid, 3,4-dihydroxysulfonic acid, 3,4-dihydroxybenzoic acid, hydroquinone (11.56), pyrogallol, o-, m Compounds having a phenolic hydroxyl group such as-, p-cresol, resorsonol, oximes such as acetoxime, 2-hydroxybenzaldehyde oxime, dimethylglyoxime, ethanediamide dioxime, acetophenone oxime, adenosine, inosine, guanine, cytosine, hypoxanthine , Ki Nucleic acid-related substances such as Nchin, other, diethylaminomethyl acid, benzimidazole, and the like barbituric acid is preferably exemplified.

  To the developer and replenisher, various surfactants and organic solvents are added as necessary for the purpose of promoting and suppressing developability, dispersing development residue, or improving ink affinity of the printing plate image area. it can. As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acid, antifoaming agent, hard water, if necessary. Softeners and the like can be added.

  The lithographic printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. Thereafter, these processes can be used in various combinations as a post-process when used as a printing plate.

Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of developer can be obtained without replacing the developer in the developer tank for a long time. It is known that PS plates can be processed. This replenishment method is also preferably applied in the present invention. Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area.
Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment of the printing plate precursor according to the present invention, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution can also be applied.

  In the photosensitive lithographic printing plate according to the present invention, an image portion unnecessary for the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming (for example, a film edge of an original film) If there is a mark, the unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, leaving it for a predetermined time, and then washing with water. As described in JP-A-59-174842, a method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to make a lithographic printing plate with a higher printing durability, if desired, Burning process is performed.
In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). The In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.
[Examples 1 to 3, Comparative Examples 1 and 2]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to a surface of an aluminum plate, it is mechanically rotated by a roller-like nylon brush. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to carry out an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

(C) Desmut treatment A desmut treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform is electrochemically roughened using a carbon electrode as the counter electrode, using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(F) Desmut treatment Desmut treatment by spraying was performed with a 15% by weight aqueous solution of sulfuric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkaline etching treatment An aluminum plate is etched by spraying at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, and the aluminum plate is dissolved at 0.10 g / m ² , so The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid at a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

<Support A>
The steps (a) to (j) were sequentially performed, and the support A was produced so that the etching amount in the step (e) was 3.4 g / m ² .
<Support B>
A support B was prepared by sequentially performing the steps except for omitting the steps (g), (h), and (i) among the above steps.

<Support C>
A support C was prepared by sequentially performing the steps except that the steps (a), (g), (h), and (i) were omitted.
<Support D>
Except for omitting the process of the above step (a) and (d) (e) (f ) performs the steps in turn, supported as total amount of electricity is 450C / dm ² in step (g) Body D was prepared.
The following supports A, B, C and D were then subjected to the following hydrophilic treatment and undercoating treatment.

(K) Alkali metal silicate treatment An aluminum support obtained by anodizing treatment was immersed in a treatment layer of a 1 mass% aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silica. Acid salt treatment (silicate treatment) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

<Support E>
An aluminum plate having a thickness of 0.24 mm was degreased with an aqueous solution of sodium hydroxide, and this was electropolished in a 20% hydrochloric acid bath to obtain a grained plate having a center line average roughness (Ra) of 0.5 μm. . Then, this grained plate was anodized in a 20% sulfuric acid bath at a current density of 2 A / dm ² to form an oxide film of 2.7 g / m ² , washed with water and dried to provide an aluminum support. Body E was obtained.

[Undercoating]
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying was 15 mg / m ² .

(Undercoat liquid)
・ The following polymer compound (I or II) 0.3 g
・ Methanol 100g
・ Water 1g

(Formation of photosensitive layer)
Next, the lower layer coating solution A having the following composition was applied to the support with the undercoat layer obtained above with a wire bar, and then dried in a drying oven at 140 ° C. for 50 seconds to obtain a coating amount of 0.85 g. / M ² .
The top layer coating solution B having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying at 140 ° C. for 60 seconds was performed to obtain positive photosensitive lithographic printing plates of Examples 1 to 3 and Comparative Examples 1 and ² at a total coating amount of 1.07 g / m ² .

<Coating liquid A for lower layer>
-Resin having specific structural units (A) listed in Table 1. 2.13 g
・ Cyanine dye X (the following structure) 0.134 g
・ Bis-p-hydroxyphenylsulfone 0.126 g
・ Tetrahydrophthalic anhydride 0.19g
・ 0.008 g of p-toluenesulfonic acid
・ 2-methoxy-4- (N-phenylamino) benzenediazonium ・ hexafluorophosphate 0.032 g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
-Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.) 0.023g
・ Γ-Butyrolactone 13.16g
・ Methyl ethyl ketone 25.39g
・ 1-methoxy-2-propanol 12.95 g

<Coating solution B for top layer>
・ Surfactant 1 less than HLB 10 listed in Table 1 0.04 g
-HLB10 or higher surfactant 2 listed in Table 1 0.01 g
M-cresol / p-cresol novolak resin (molar ratio 60:40, weight average molecular weight 5,000) 0.341 g
・ Cyanine dye P (the following structure) 0.019 g
・ The following structural polymer Q / MEK 30% solution (the following structure) 0.14 g
・ Quaternary ammonium salt R (the following structure) 0.004g
・ Methyl ethyl ketone 2.63g
・ 1-methoxy-2-propanol 5.27g

[Examples 4 to 6, Comparative Examples 3 and 4]
The coating liquid C having the following composition was applied to a support with an undercoat layer obtained by the same method as in Examples 1 to 4 with a wire bar. After coating, drying was performed at 140 ° C. for 60 seconds to obtain positive photosensitive lithographic printing plates of Examples 4 to 6 and Comparative Examples 3 and 4, with a total coating amount of 1.80 g / m ² .

<Coating liquid C>
・ Surfactant 1 with less than 10 HLB listed in Table 1 0.025 g
-HLB10 or higher surfactant 2 listed in Table 1 0.025g
-Resin having specific structural unit (A) listed in Table 1 0.75 g
-M-cresol / p-cresol novolac resin (molar ratio 60:40, weight average molecular weight 5,000) 0.25 g
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
・ Cyanine dye P (structure shown below) 0.017g
・ Victoria Pure Blue (Dye with BOH counter anion as 1-naphthalenesulfonic acid anion) 0.015 g
・ Γ-Butyllactone 10g
・ Methyl ethyl ketone 10g
1-methoxy-2-propanol 1g

[Examples 7 to 9, Comparative Examples 5 and 6]
The coating liquid D having the following composition was applied to a support with an undercoat layer obtained by the same method as in Examples 1 to 4 with a wire bar. After coating, drying was performed at 150 ° C. for 100 seconds to obtain positive photosensitive lithographic printing plates of Examples 7 to 9 and Comparative Examples 5 and 6, with a total coating amount of 1.40 g / m ² .

<Coating liquid D>
・ Surfactant 1 with less than 10 HLB listed in Table 1 0.025 g
-HLB10 or higher surfactant 2 listed in Table 1 0.025g
-Resin having a specific structural unit (A) listed in Table 1 2.072 g
・ Cyanine dye P (structure shown below) 0.052g
・ Ethyl violet 6-naphthalenesulfonic acid 0.078g
・ Methyl ethyl ketone 25.30g

[Evaluation of photosensitive planographic printing plate]
Next, the performance evaluation of the positive photosensitive lithographic printing plates of Examples 1 to 9 and Comparative Examples 1 to 6 was performed. The evaluation test was conducted on the sample stored at 25 ° C. for 14 days after the photosensitive layer was applied.

(Evaluation of development latitude)
The obtained positive photosensitive lithographic printing plates of Examples 1 to 9 and Comparative Examples 1 to 6 were drawn in a test pattern image on a Trend setter 800 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm. (Exposure) was performed.
Next, a solution in which carbon dioxide gas was blown into the developer DT-2R manufactured by Fuji Photo Film Co., Ltd. in water (1: 9) until the electrical conductivity reached 37 mS / cm, and a finisher manufactured by Fuji Photo Film Co., Ltd. Using a PS processor LP-940HII manufactured by Fuji Photo Film Co., Ltd., in which a FG-1 aqueous dilution (1: 1) solution was charged, development was performed at a developing time of 12 seconds while maintaining the solution temperature at 30 ° C. Thereafter, an appropriate amount of DT-2R diluted with water (1: 9) was added to the developer, the conductivity was adjusted to 39 mS / cm, and the plate on which the test pattern was drawn in an image was developed as before. Further, the electrical conductivity was increased by 2 mS / cm, and this operation was continued until a film loss due to image development was observed remarkably.

In the developed plates of Examples and Comparative Examples after development, the plates developed with each conductivity were checked with a magnifier of 50 times to see whether there was any stain or coloring due to poorly developed non-image area residual film. The conductivity of the developer that could be developed was determined. Next, the electric conductivity at the limit at which the reduction of the developed film is maintained to such an extent that the printing durability is not substantially affected, specifically, the image density of the solid portion before development is measured by GRETAG reflection densitometer D196 (manufactured by GretagMacbeth). And the conductivity of the developer having a solid portion having an image density of 0.10 or more less than this image density was determined.
The development latitude was defined as the electric conductivity of the developer that was able to be developed satisfactorily and the limit of electric conductivity at which the reduction of the developed film was maintained to such an extent that it did not substantially affect printing durability. As a result, for Examples 1 to 9, a sufficiently wide development latitude was obtained.

(Evaluation of chemical resistance)
To the positive photosensitive lithographic printing plates of Examples 1 to 9 and Comparative Examples 1 to 6, a cleaner liquid (Fuji Photo Film Co., Ltd .: “Plate Cleaner CL2”) was dropped. The concentration change of the dripping part after 1 minute was compared visually. As a result, about Examples 1-9, the result without a problem in chemical resistance was obtained.

(Small dot printing durability)
The obtained positive photosensitive lithographic printing plates of Examples 1 to 9 and Comparative Examples 1 to 6 were 175 lpi / 2400 dpi / 2 at a beam strength of 10.0 W and a drum rotation speed of 250 rpm on a Trendsetter 3244 manufactured by Creo. % Halftone dot test pattern was drawn (exposure), and the plate exposed under the above conditions was diluted with a developer DT-2 manufactured by Fuji Photo Film Co., Ltd. (with a conductivity of 43 mS / cm). ) And Fuji Photo Film Co., Ltd. Finisher-FP-2W (diluted 1: 1) and Fuji Photo Film Co., Ltd. PS Processor-LP-940H, and the liquid temperature was adjusted to 30 ° C. Development was carried out with a keeping development time of 12 seconds. Then, it printed with the Heidel KOR-D machine. Table 1 shows the number of prints that produced a normal printed matter.

(A) Resin
(1): Methacrylic acid / N-phenylmaleimide / methacrylamide (molar ratio 15/50/35, weight average molecular weight 3000)
(2): Methacrylic acid / N-cyclohexylmaleimide / methacrylamide (molar ratio 15/50/35, weight average molecular weight 5000)
(3): Methacrylic acid / N-phenylmaleimide / N-methoxymethylmethacrylamide (molar ratio 20/45/35, weight average molecular weight 7000)
(4): Methacrylic acid / N-cyclohexylmaleimide / N-methoxymethylmethacrylamide (molar ratio 25/40/35, weight average molecular weight 10000)
Surfactant 1
1-a: GO-4: polyoxyethylene sorbit tetraoleate (manufactured by Nikko Chemicals)
Surfactant 2
2-a: MYS-25: Polyethylene glycol monostearate (Nikko Chemicals)
2-b: MYS-10: Polyethylene glycol monostearate (manufactured by Nikko Chemicals)

  As described above, the infrared-sensitive composition containing (A) a resin having a structural unit represented by the general formula (1) of the present invention, (B) a surfactant of less than HLB10, and (C) a surfactant of HLB10 or more. Thus, a photosensitive lithographic printing plate having a wide development latitude and excellent chemical resistance and printing durability was obtained (Examples 1 to 9). On the other hand, in the case of using the infrared-sensitive photosensitive composition lacking any of the components (A) to (C), all exhibited low small dot printing durability (Comparative Examples 1 to 6).

Claims (2)

(A) Sensation containing a resin having a structural unit represented by the general formula (1), (B) a surfactant of less than HLB10, (C) a surfactant of HLB10 or more, and (D) an infrared absorber. Infrared photosensitive composition.

In general formula (1), R < ₁ > -R < ₃ > represents arbitrary substituents. (A) In the general formula (1), R ₁ is hydrogen; unsubstituted or optionally substituted (C ₆ -C ₁₂ ) aryl; unsubstituted or optionally substituted (C ₁ -C ₁₂ ) alkyl; An unsubstituted or optionally substituted (C ₃ -C ₁₀ ) cycloalkyl; an unsubstituted or optionally substituted arylsulfonamido group; or an unsubstituted or optionally substituted sulfonamido group, R ₂ and R ₃ are independently hydrogen, halogen, (C ₁ -C ₄₎ alkyl, and is selected from the group consisting of phenyl, claim 1 infrared-sensitive photosensitive composition.