JP2008298938A - Positive photosensitive lithographic printing plate material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photosensitive lithographic printing plate material which retains good developability and has excellent printing durability. <P>SOLUTION: The positive photosensitive lithographic printing plate material has a lower image forming layer containing an alkali-soluble resin, an acid decomposable compound and an acid generator on an aluminum support, and has an upper image forming layer containing an alkali-soluble resin on the lower image forming layer, wherein the lower image forming layer contains a copolymer containing a repeating unit represented by general formula (1) as the alkali-soluble resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate material having a positive-type image forming layer used in a so-called computer-to-plate (hereinafter referred to as “CTP”) system, and more particularly to a near-infrared laser. The present invention relates to a positive photosensitive lithographic printing plate material capable of forming an image by exposure.

  2. Description of the Related Art In recent years, in printing plate preparation techniques for offset printing, a number of CTP systems that directly expose a lithographic printing plate precursor with a laser light source based on digital image data and record the image have been developed and put into practical use.

  In particular, the development and popularization of so-called thermal CTP systems, CTP systems that record with near-infrared light, with the increase in output, size, and price of solid-state lasers and semiconductor lasers having emission wavelengths in the near-infrared region It's amazing.

  As a lithographic printing plate material for an infrared laser, a recording layer containing (A) an aqueous alkali-soluble resin having a phenolic hydroxyl group such as cresol novolak resin described in WO 97/39894 and (B) an infrared absorber There is known a positive planographic printing plate precursor having:

  In this positive type lithographic printing original plate, the association state of the cresol novolak resin is changed by the action of heat generated by the infrared absorber in the exposed area, resulting in a difference in solubility (dissolution rate difference) from the unexposed area. Is used to develop and form an image. However, since the difference in dissolution rate is small, there is a problem that the development latitude is narrow.

  In order to solve the above problem, an infrared absorber described in Japanese Patent No. 3644002 and JP-A-7-285275, and a compound that is activated by the generated heat to generate an acid, such as an onium salt, a quinonediazide compound, There has been proposed a lithographic printing plate material using a technique in which a triazine compound and a compound that decomposes with an acid, for example, a compound that decomposes with an acid having a ketal group, coexist.

  Further, a lithographic printing plate material using a compound that absorbs light and generates heat and having two photosensitive layers is known (see Patent Document 1).

However, in these lithographic printing plate materials, there is a problem that if the printing durability is improved, the developability of the non-image area is lowered, and high printing durability can be obtained while maintaining good developability. Was difficult.
JP 11-218914 A

  An object of the present invention is to provide a positive photosensitive lithographic printing plate material that maintains good developability and is excellent in printing durability.

The above object of the present invention is achieved by the following configurations.
1. A positive photosensitive material having an image forming layer lower layer containing an alkali-soluble resin, an acid-decomposable compound and an acid generator on an aluminum support, and an image forming layer upper layer containing an alkali-soluble resin on the image forming layer lower layer. A lithographic printing plate material, wherein the lower layer of the image-forming layer contains a copolymer containing a repeating unit represented by the following general formula (1) as the alkali-soluble resin: Printing plate material.

(In the formula, A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, X represents an alkylene group, and Y represents a carboxyl group or a group having a base thereof, a sulfo group or a salt thereof, a phosphonoxy group, a dialkylphospho group. Represents a nonoxy group, a trialkoxysilyl group, or an alkyldialkoxysilyl group.)
2. 2. The positive photosensitive lithographic printing plate material according to 1, wherein X is an ethylene group.

  With the above-described configuration of the present invention, there is no deterioration in the removability of the image forming layer from the support in the non-image area at the time of development, positive photosensitivity that maintains good developability and has excellent printing durability. Lithographic printing plate materials can be provided.

  Hereinafter, the present invention will be described in more detail.

  The present invention is a positive photosensitive lithographic printing plate material having an image forming layer lower layer (hereinafter also simply referred to as a lower layer) containing an alkali-soluble resin, an acid-decomposable compound and an acid generator on an aluminum support. , A positive photosensitive lithographic printing plate material having an image-forming layer upper layer (hereinafter also referred to simply as an upper layer) containing an alkali-soluble resin on the lower layer, wherein the lower layer is the above general formula ( It contains a copolymer containing the repeating unit represented by 1).

  In the positive photosensitive lithographic printing plate material having at least two image forming layers, the present invention contains the specific alkali-soluble resin in the lower layer of the image forming layer, thereby maintaining high sensitivity and printing durability. A positive photosensitive lithographic printing plate material having excellent properties can be provided.

(Aluminum support)
The aluminum support according to the present invention is a pure aluminum plate or an aluminum alloy plate.

  Various aluminum alloys can be used, for example, alloys of aluminum and metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, etc. An aluminum plate produced by the method can be used. In addition, a recycled aluminum plate obtained by rolling recycled aluminum ingots such as scrap materials and recycled materials that are becoming popular in recent years can also be used.

  The aluminum support according to the present invention preferably has a roughened surface in order to enhance water retention when used in printing.

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

  Next, a roughening process is performed. Examples of the roughening method include a mechanical method and a method of etching by electrolysis. In the present invention, AC electrolytic surface roughening treatment in an electrolytic solution mainly composed of hydrochloric acid is preferable, but prior to that, mechanical surface roughening treatment and electrolytic surface roughening treatment mainly composed of nitric acid may be performed.

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

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

The electrolytic surface-roughening treatment mainly composed of nitric acid can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 20 to 100 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of nitric acid in the electrolytic solution is preferably 0.1 to 5% by mass. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, aluminum ions, and the like can be added to the electrolytic solution.

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

In the AC electrolytic surface roughening treatment in an electrolytic solution mainly composed of hydrochloric acid, the hydrochloric acid concentration is 5 to 20 g / l, preferably 6 to 15 g / l. The current density is 15 to 120 A / dm ² , preferably 20 to 90 A / dm ² . The quantity of electricity was 400~2000C / dm ^2, preferably 500~1200C / dm ^2. The frequency is preferably in the range of 40 to 150 Hz. The temperature of the electrolytic solution can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, aluminum ions, and the like can be added to the electrolytic solution.

After the electrolytic surface roughening treatment is performed in the above-described electrolytic solution mainly composed of hydrochloric acid, it is preferably immersed in an aqueous solution of acid or alkali in order to remove aluminum scraps on the surface. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an alkaline aqueous solution. The amount of aluminum dissolved on the surface is preferably 0.5 to ² g / m2. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  The arithmetic average roughness (Ra) of the surface on the photosensitive layer side of the obtained aluminum support is preferably 0.4 to 0.6 μm, and is controlled by a combination of hydrochloric acid concentration, current density, and electric quantity in the roughening treatment. I can do it.

Following the roughening treatment, an anodizing treatment is performed to form an anodized film. The anodizing method according to the present invention is preferably carried out using sulfuric acid or an electrolytic solution mainly composed of sulfuric acid as the electrolytic solution. The concentration of sulfuric acid is preferably 5 to 50% by mass, particularly preferably 10 to 35% by mass. The temperature is preferably 10 to 50 ° C. The treatment voltage is preferably 18V or more, and more preferably 20V or more. Current density is preferably 1~30A / dm ^2. Quantity of electricity is preferably from 200~600C / dm ^2.

The formed anodic oxidation coating amount is preferably ² to 6 g / m ² , and preferably 3 to 5 g / m ² . The anodic oxidation coating amount is obtained by, for example, immersing an aluminum plate in a chromic phosphate solution (produced by dissolving 85% phosphoric acid solution: 35 ml, chromium oxide (IV): 20 g in 1 L of water), dissolving the oxide coating, It is calculated | required from the mass change measurement etc. before and after melt | dissolution of the coating. Micropores are generated in the anodized film, and the density of the micropores is preferably 400 to 700 / μm ^{2, and} more preferably 400 to 600 / μm ² .

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

<Hydrophilic treatment>
The aluminum support is preferably subjected to a hydrophilization treatment after these treatments in terms of sensitivity and the like.

  Hydrophilization treatment is not particularly limited, but water-soluble resins such as phosphonic acids having amino groups such as polyvinylphosphonic acid, polyvinyl alcohol and derivatives thereof, carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, sulfonic acid Polymers and copolymers having a group in the side chain, polyacrylic acid, a water-soluble metal salt (for example, zinc borate), or a primer coated with a yellow dye, an amine salt, or the like can be used.

  Furthermore, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-5-304358 is covalently used. It is preferable to perform a hydrophilic treatment with an aqueous solution containing polyvinylphosphonic acid.

  The treatment is not limited to a coating method, a spray method, a dip method, or the like, but a dip method is suitable for making the equipment inexpensive. In the case of a dip type, it is preferable to treat polyvinylphosphonic acid with a 0.05 to 3% aqueous solution. The treatment temperature is preferably 20 to 90 ° C., and the treatment time is preferably 10 to 180 seconds. After the treatment, it is preferable to perform a squeegee treatment or a water washing treatment in order to remove the excessively laminated polyvinylphosphonic acid. Furthermore, it is preferable to perform a drying process.

  As drying temperature, 40-180 degreeC is preferable, More preferably, it is 50-150 degreeC. The drying treatment is preferable because the adhesion to the lower layer and the function as a heat insulating layer are improved, and the chemical resistance and sensitivity are improved.

  The thickness of the hydrophilic treatment layer is preferably from 0.002 to 0.1 μm, more preferably from 0.005 to 0.05 μm from the viewpoints of adhesiveness, heat insulation, and sensitivity.

(Image formation layer lower layer)
The lower layer of the image forming layer according to the present invention is a layer provided on the aluminum support and contains an alkali-soluble resin, an acid-decomposable compound and an acid generator.

(Alkali-soluble resin)
The alkali-soluble resin according to the present invention is a resin that dissolves in an aqueous potassium hydroxide solution having a pH of 13 at 25 g at 0.1 g / l or more.

  The lower layer according to the present invention contains a copolymer containing at least a repeating unit represented by the general formula (1) as an alkali-soluble resin.

  In general formula (1), A represents a hydrogen atom and an alkyl group having 1 to 4 carbon atoms, X represents an alkylene group, Y represents a carboxyl group or a group having a base thereof, a sulfo group or a salt thereof, or a phosphonoxy group. Represents a dialkylphosphonoxy group, a trialkoxysilyl group, and an alkyldialkoxysilyl group.

  Examples of the alkyl having 1 to 4 carbon atoms represented by A include a methyl group, an ethyl group, a propyl group, and a butyl group, and a methyl group is particularly preferable.

  Examples of the alkylene group represented by X include a methylene group, an ethylene group, a propylene group, and a butylene group, and an ethylene group is particularly preferably used. Examples of the carboxyl group represented by Y or a group having a base thereof include a carboxyl group, a cation base of a carboxyl group, an alkoxy group having a carboxyl group, a cation base of a carboxyl group, and an aryloxy group. Although the specific example of a compound containing the repeating unit represented by General formula (1) is shown, it is not limited to these.

  The repeating unit represented by the general formula (1) is preferably contained in the copolymer in an amount of 1 to 20 mol%, more preferably 1 to 5 mol%.

  The content of the repeating unit of the general formula (1) contained in the lower layer of the image forming layer is preferably 0.001 to 0.01 mmol / g.

  As Y contained in the repeating unit represented by the general formula (1), a sulfo group is preferable. In addition, when Y is an acid group, it is particularly preferable to exist in the form of a salt.

  Other copolymer components of the copolymer according to the present invention include, for example, acrylic esters, methacrylic esters, acrylamides, methacrylamides, vinyl esters, styrenes, acrylic acid, methacrylic acid, acrylonitrile, Known monomer components such as maleic anhydride, maleic imide, and lactones may be mentioned.

  Specific examples of acrylates that can be used include methyl acrylate, ethyl acrylate, (n- or i-) propyl acrylate, (n-, i-, sec- or t-) butyl acrylate, amyl acrylate, 2 -Ethylhexyl acrylate, dodecyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 5-hydroxypentyl acrylate, cyclohexyl acrylate, allyl acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, glycidyl acrylate, benzyl Acrylate, methoxybenzyl acrylate, chlorobenzyl acrylate, 2- (p-hydroxyphenyl) ethyl acetate Rate, furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, chlorophenyl acrylate, sulfamoyl phenyl acrylate, and the like.

  Specific examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, (n- or i-) propyl methacrylate, (n-, i-, sec- or t-) butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, Dodecyl methacrylate, chloroethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 5-hydroxypentyl methacrylate, cyclohexyl methacrylate, allyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, glycidyl methacrylate, methoxybenzyl methacrylate, chloro Benzyl methacrylate, 2- (p-hydroxyphenyl) ethyl methacrylate Rate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, chlorophenyl methacrylate, sulfamoylphenyl methacrylate and the like.

  Specific examples of acrylamides include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, N-benzylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, and N-tolylacrylamide. N- (p-hydroxyphenyl) acrylamide, N- (sulfamoylphenyl) acrylamide, N- (phenylsulfonyl) acrylamide, N- (tolylsulfonyl) acrylamide, N, N-dimethylacrylamide, N-methyl-N- Examples include phenylacrylamide, N-hydroxyethyl-N-methylacrylamide, N- (p-toluenesulfonyl) acrylamide and the like.

  Specific examples of methacrylamides include methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-butylmethacrylamide, N-benzylmethacrylamide, N-hydroxyethylmethacrylamide, N -Phenylmethacrylamide, N-tolylmethacrylamide, N- (p-hydroxyphenyl) methacrylamide, N- (sulfamoylphenyl) methacrylamide, N- (phenylsulfonyl) methacrylamide, N- (tolylsulfonyl) methacrylamide N, N-dimethylmethacrylamide, N-methyl-N-phenylmethacrylamide, N- (p-toluenesulfonyl) methacrylamide, N-hydroxyethyl-N-methylmethacrylamide and the like.

  Specific examples of lactones include pantoyl lactone (meth) acrylate, α- (meth) acryloyl-γ-butyrolactone, and β- (meth) acryloyl-γ-butyrolactone.

  Specific examples of maleic imides include maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide and the like.

  Specific examples of vinyl esters include vinyl acetate, vinyl butyrate, vinyl benzoate and the like.

  Specific examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, propyl styrene, cyclohexyl styrene, chloromethyl styrene, trifluoromethyl styrene, ethoxymethyl styrene, acetoxymethyl styrene, methoxy styrene, dimethoxy styrene. Chlorostyrene, dichlorostyrene, bromostyrene, iodostyrene, fluorostyrene, carboxystyrene and the like.

  Specific examples of acrylonitriles include acrylonitrile and methacrylonitrile.

  Among these monomer components, acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, acrylic acid, methacrylic acid, acrylonitriles, maleic imides having 20 or less carbon atoms are particularly preferably used. Etc.

  Among these, a copolymer containing acrylonitrile and methacrylic acid esters is particularly preferably used.

  The content of the copolymer according to the present invention relative to the lower layer of the image forming layer is preferably 60% by mass or more, more preferably 65% by mass or more, particularly preferably 70% by mass or more from the viewpoint of sensitivity and development latitude.

  The molecular weight of the copolymer according to the present invention is preferably 2000 or more in terms of sensitivity and development latitude in terms of mass average molecular weight (Mw), more preferably in the range of 50,000 to 100,000, particularly preferably. 10,000 to 50,000.

  The copolymer according to the present invention may be used alone or in combination of two or more.

  The copolymer according to the present invention can be obtained by general radical reaction polymerization. That is, a monomer having a double bond, which is a precursor of the repeating unit represented by the general formula (1), another copolymer component, and a radical polymerization initiator such as azobisisobutylnitrile in a reaction solvent. It can be obtained by carrying out the polymerization reaction by heating.

  As the alkali-soluble resin, in addition to the copolymer of the present invention, other alkali-soluble resins may be used in combination as long as the effects of the present invention are not impaired.

  Examples of other alkali-soluble resins include resins having phenolic hydroxyl groups, acrylic resins, and acetal resins.

(Acid generator)
The acid generator according to the present invention is a compound that generates an acid upon image exposure.
Examples of the acid generator include salts of polyhalogen compounds, diazonium, phosphonium, sulfonium, and iodonium such as BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , SiF ₆ ²⁻ , ClO ₄ ⁻ , organic halogen compounds, and orthoquinone-di And azidosulfonyl chloride.

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

Formula (2) R ¹ —C (X) ₂ — (C═O) —R ²
In general formula (2), R ¹ represents a bromine atom, a chlorine atom, an alkyl group, an aryl group, an acyl group, an alkylsulfonyl group, an arylsulfonyl group, an iminosulfonyl group, or a cyano group. R ² represents a hydrogen atom or a monovalent organic substituent. R ¹ and R ² may combine to form a ring. X represents a bromine atom or a chlorine atom.

Among the compounds represented by the general formula (2), those in which R ¹ is a bromine atom or a chlorine atom are preferably used in terms of sensitivity.

The monovalent organic substituent represented by R ² is not particularly limited, but —R ² represents —O—R ³ or —NR ⁴ —R ³ (R ³ represents a hydrogen atom or a monovalent organic substituent). , R ⁴ represents a hydrogen atom or an alkyl group).

Also in this case, in particular, those in which R ¹ is a bromine atom or a chlorine atom are preferably used from the viewpoint of sensitivity.

  Further, among these compounds, compounds having at least one acetyl group selected from a tribromoacetyl group, a dibromoacetyl group, a trichloroacetyl group and a dichloroacetyl group in the molecule are preferable. Further, from the viewpoint of synthesis, at least one selected from a tribromoacetoxy group, a dibromoacetoxy group, a trichloroacetoxy group and a dichloroacetoxy group, which is obtained by reacting a monovalent or polyvalent alcohol with the corresponding acid chloride. Tribromoacetylamide group, dibromoacetylamide group, trichloroacetylamide group and dichloroacetyl obtained by the reaction of a compound having an acetoxy group or a monovalent or polyvalent primary amine with the corresponding acid chloride. A compound having at least one acetylamide group selected from amide groups is particularly preferred. Further, compounds having a plurality of these acetyl groups, acetoxy groups, and acetamide groups are also preferably used.

  These compounds can be easily synthesized under the conditions of ordinary esterification or amidation reaction.

  A typical synthesis method of the polymerization initiator of the present invention represented by the general formula (2) uses acid chlorides such as tribromoacetic acid chloride, dibromoacetic acid chloride, trichloroacetic acid chloride, dichloroacetic acid chloride corresponding to each structure. In this reaction, a derivative such as alcohol, phenol or amine is esterified or amidated.

  Alcohols, phenols, and amines used in the above reaction are arbitrary, for example, monovalent alcohols such as ethanol, 2-butanol, 1-adamantanol, diethylene glycol, trimethylolpropane, dipentaerythritol, etc. Polyhydric alcohols Phenols such as phenol, pyrogallol, naphthol, monovalent amines such as morpholine, aniline, 1-aminodecane, polyvalent amines such as 1,2-dimethylpropylenediamine, 1,12-dodecanediamine, etc. Can be mentioned.

  Examples of the compound represented by the general formula (2) are listed below.

  The content of the acid generator is preferably 0.1% by mass to 30% by mass and particularly preferably 1% by mass to 15% by mass with respect to the lower layer in terms of sensitivity and handleability in a bright room.

(Acid-decomposable compound)
The acid-decomposable compound according to the present invention is a compound that can be decomposed in the lower layer by an acid generated from an acid generator by image exposure.

  Specifically, for example, it is described in the specifications of JP-A-48-89003, 51-120714, 53-133429, 55-12995, 55-126236, and 56-17345. Compounds having a C—O—C bond, compounds having a Si—O—C bond described in the specifications of JP-A-60-37549 and JP-A-60-121446, JP-A-60- Other acid-decomposable compounds described in the specifications of Nos. 3625 and 60-10247 may be mentioned.

  Furthermore, compounds having a Si—N bond described in the specification of JP-A-62-222246, carbonate esters described in the specification of JP-A-62-251743, and JP-A-62-2 The ortho carbonate ester described in the specification of No. 209451, the ortho titanate ester described in the specification of JP-A No. 62-280842, and the specification of JP-A No. 62-280842 are described. Orthosilicate esters, acetals and ketals described in the specification of JP-A No. 2000-221676, compounds having a C—S bond described in the specification of JP-A No. 62-244038, Phenolphthalein, cresolphthalein and phenolsulfophthalein described in Kaikai 2005-91802 were protected with heat or acid-decomposable groups. Such compounds, and the like.

  Among these, compounds having at least one acetal or ketal group are preferred from the viewpoint of improving reaction efficiency with acid, that is, sensitivity and development latitude.

Also in terms of sensitivity and developability of the _{balance, - (CH 2 CH 2 O} ) n- group (n is an integer of 2 to 5) include compounds having the. Among these compounds, compounds having an ethyleneoxy group chain number n of 3 or 4 are preferred.

The - (CH ₂ CH ₂ O) dimethoxycyclohexane Specific examples of the compound having an n- group, benzaldehyde and the substituted derivatives thereof, diethylene glycol, triethylene glycol, produce condensation of any of tetraethylene glycol and pentaethylene glycol Things.

  Preferable compounds of the acid decomposition compound according to the present invention include compounds represented by the following general formula (ADC-1).

(In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be bonded to each other through a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group to form a ring.)
More preferred is a compound of the following general formula (ADC-2).

(In the formula, R ₅ and R ₆ may be bonded to each other by a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group to form a ring. R ₇ is an alkylene group, a cycloalkylene group or an arylene group. And n and m are integers of 1 or more.)
In the present invention, the content of the acid-decomposing compound is preferably 0.5 to 50% by mass, particularly preferably 1 to 30%, based on the total solid content of the composition forming the lower layer, in terms of sensitivity and printing durability. % By mass.

  The acid decomposition compound may be used alone or in combination of two or more. The acid-decomposable compound of the present invention may be used in the upper layer of the image forming layer.

  Specific examples are given below, but the present invention is not limited thereto.

(Image forming layer upper layer)
The upper layer of the image forming layer according to the present invention contains an alkali-soluble resin. As described above, the alkali-soluble resin is a resin that dissolves in an aqueous potassium hydroxide solution having a pH of 13 or more in an amount of 0.1 g / l.

  As the alkali-soluble resin contained in the upper layer, a resin having a phenolic hydroxyl group, an acetal resin, a urethane resin, or the like can be used.

  Examples of the resin having a phenolic hydroxyl group include a copolymer and a novolak resin according to the present invention.

  Among these, as a resin used for the upper layer, a novolak resin and the copolymer according to the present invention are preferable, and a novolak resin is particularly preferable.

(Novolac resin)
The novolac resin is a resin obtained by condensing phenols with aldehydes. Phenols used in the synthesis of the novolak resin that can be used in the present invention include phenol, m-cresol, p-cresol, m- / p-mixed cresol, phenol and cresol (m-, p-, or m- / p-mixture), phenols such as pyrogallol, isopropylphenol, t-butylphenol, t-amylphenol, hexylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isopropyl Examples thereof include substituted phenols such as cresol, t-butylcresol, and t-amylresole.

  On the other hand, examples of aldehydes include aliphatic and aromatic aldehydes such as formaldehyde, acetaldehyde, acrolein, and crotonaldehyde. Preferred is formaldehyde or acetaldehyde, and most preferred is formaldehyde.

  Among the above combinations, preferably phenol-formaldehyde, m-cresol-formaldehyde, p-cresol-formaldehyde, m- / p-mixed cresol-formaldehyde, phenol / cresol (m-, p-, o-, m- / Any of p-mixing, m- / o-mixing and o- / p-mixing.) Mixed-formaldehyde.

  Particularly preferred is cresol (m-, p-mixed) -formaldehyde.

  These novolak resins preferably have a weight average molecular weight of 1,000 or more and a number average molecular weight of 200 or more. More preferably, the weight average molecular weight is 1500 to 300,000, the number average molecular weight is 300 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. Particularly preferably, the weight average molecular weight is 2,000 to 10,000, the number average molecular weight is 500 to 10,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 5. .

  As a method for producing a novolak resin, for example, as described in “New Experimental Chemistry Course [19] Polymer Chemistry [I]” (1993, Maruzen Publishing), Item 300, phenol and substituted phenols (for example, xylenol) , Cresols, etc.) in a solvent using acid as a catalyst together with an aqueous formaldehyde solution to dehydrate and condense phenol, the o-position or p-position of the substituted phenol component, and formaldehyde. After dissolving the novolak resin thus obtained in an organic polar solvent, an appropriate amount of a nonpolar solvent is added and left for several hours, whereby the novolak resin solution is separated into two layers. By concentrating only the lower layer of the separated solution, a novolak resin with a concentrated molecular weight can be produced.

  A novolac resin may be used independently and may use 2 or more types together. By combining two or more kinds, it is possible to effectively use different characteristics such as film strength, alkali solubility, solubility in chemicals, and interaction with a photothermal conversion substance, which is preferable.

(Acetal resin)
The acetal resin that can be used in the present invention can be synthesized by a method in which polyvinyl alcohol is acetalized with an aldehyde and the remaining hydroxy group is reacted with an acid anhydride.

  Examples of the aldehyde used herein include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentylaldehyde, hexylaldehyde, glyoxylic acid, N, N-dimethylformamide di-n-butyl acetal, bromoacetaldehyde, chloroacetaldehyde, 3-hydroxy- Examples include n-butyraldehyde, 3-methoxy-n-butyraldehyde, 3- (dimethylamino) -2,2-dimethylpropionaldehyde, cyanoacetaldehyde and the like.

(Polyurethane resin)
Examples of the polyurethane resin that can be used in the present invention include alkali developer-soluble polyurethane resins containing 0.4 meq / g or more of carboxyl groups described in JP-A-5-281718 and JP-A-11-352691.

  Specifically, it is a polyurethane resin having as a basic skeleton a structural unit represented by a reaction product of a diisocyanate compound and a diol compound having a carboxyl group. As the diol compound, a diol compound having no carboxyl group is preferably used in combination for the purpose of adjusting the carboxyl group content and controlling the physical properties of the polymer.

  The thickness of the upper layer according to the present invention is preferably 0.01 μm to 3.0 μm, particularly preferably 0.05 μm to 2.0 μm.

(Visible paint)
The upper layer and the lower layer according to the present invention preferably contain a colorant as a visible paint. Examples of the colorant include oil-soluble dyes and basic dyes including salt-forming organic dyes.

  Particularly preferred are those that change color tone by reacting with free radicals or acids. “Color tone changes” includes both a change from colorless to colored color tone and a change from colored to colorless or different colored tone. Preferred dyes are those that change color tone by forming a salt with an acid.

  For example, Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Co., Ltd.), Patent Pure Blue (Sumitomo Sangoku Chemical Co., Ltd.), Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Violet, Methyl Triphenylmethane series represented by green, erythrosin B, pacific fuchsin, malachite green, oil red, m-cresol purple, rhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, cyano-p-diethylaminophenylacetanilide, etc. , Diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based pigments that change from colored to colorless or different colored tones And the like to.

  On the other hand, examples of the color changing agent that changes from colorless to colored include leuco dyes and, for example, triphenylamine, diphenylamine, o-chloroaniline, 1,2,3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis. -Dimethylaminodiphenylamine, 1,2-dianilinoethylene, p, p ', p "-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p', p"- Primary or secondary typified by triamino-o-methyltriphenylmethane, p, p'-bis-dimethylaminodiphenyl-4-anilinononaphthylmethane, p, p ', p "-triaminotriphenylmethane These compounds can be used alone or in combination of two or more. It can be used. In addition, particularly preferred dyes are Victoria Pure Blue BOH, an Oil Blue # 603.

  As the upper colorant, it is preferable to use a dye having an absorption maximum wavelength of less than 800 nm, particularly less than 600 nm.

  These dyes can be added to the printing plate material 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 upper layer or the lower layer.

(Development accelerator)
The lower layer or the upper layer according to the present invention may contain a compound having a low molecular weight acidic group for the purpose of improving solubility, if necessary.

  Examples of the acidic group include acidic groups having a pKa value of 7 to 11, such as a thiol group, a phenolic hydroxyl group, a sulfonamide group, and an active methylene group. The addition amount is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the lower layer.

(Development inhibitor)
The lower layer or the upper layer according to the present invention may contain various dissolution inhibitors for the purpose of adjusting solubility. As the dissolution inhibitor, a disulfone compound or a sulfone compound as disclosed in JP-A-11-119418 is preferably used, and as a specific example, it is preferable to use 4,4′-bishydroxyphenylsulfone. The addition amount is preferably 0.05 to 20% by mass, more preferably 0.5 to 10% by mass with respect to each layer.

  In addition, a development inhibitor can be contained for the purpose of enhancing dissolution inhibiting ability. The development inhibitor according to the present invention forms an interaction with the alkali-soluble resin, substantially lowers the solubility of the alkali-soluble resin in a developing solution in an unexposed area, and There is no particular limitation as long as the interaction is weakened and can be soluble in the developer, but quaternary ammonium salts, polyethylene glycol compounds and the like are particularly preferably used.

  The quaternary ammonium salt is not particularly limited, and examples thereof include tetraalkylammonium salts, trialkylarylammonium salts, dialkyldiarylammonium salts, alkyltriarylammonium salts, tetraarylammonium salts, cyclic ammonium salts, and bicyclic ammonium salts. .

  The addition amount of the quaternary ammonium salt is preferably 0.1 to 50% by mass and more preferably 1 to 30% by mass with respect to the total solid content of the upper layer from the viewpoint of the effect of suppressing development and film forming properties. preferable.

(Sensitivity improver)
The upper layer and the lower layer according to the present invention may contain cyclic acid anhydrides, phenols, and organic acids for the purpose of improving sensitivity.

  Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, 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.

  Further, examples of organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphoric esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid Acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbine An acid etc. are mentioned. The proportion of the cyclic acid anhydride, phenols and organic acids in the composition is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 10%. % By mass.

  Also, alcohol compounds in which at least one trifluoromethyl group described in JP-A-2005-99298 is substituted at the α-position can be used. This compound has the effect of improving the solubility in an alkali developer by improving the acidity of the α-position hydroxyl group due to the electron-withdrawing effect of the trifluoromethyl group.

(Back coat layer)
In the printing plate material of the present invention, a backcoat layer may be provided on the back surface of the support in order to suppress elution of the anodized film of aluminum during the development process. By providing a backcoat layer, it is preferable because development sludge is suppressed, the developer replacement period is shortened, and the amount of replenisher is reduced. Preferred embodiments of the backcoat layer include (a) a metal oxide obtained by hydrolysis and polycondensation of an organic metal compound or an inorganic metal compound, (b) a colloidal silica sol, and (c) an organic polymer compound.

  Examples of the (a) metal oxide used in the back coat layer include silica (silicon oxide), titanium oxide, boron oxide, aluminum oxide, zirconium oxide, and a composite thereof. The metal oxide in the backcoat layer used in the present invention is a so-called hydrolytic and polycondensation reaction of an organic metal compound or an inorganic metal compound in water and an organic solvent with a catalyst such as acid or alkali. It is obtained by applying a sol-gel reaction liquid to the back surface of the support and drying it. Examples of the organic metal compound or inorganic metal compound used here include metal alkoxide, metal acetylacetonate, metal acetate, metal oxalate, metal nitrate, metal sulfate, metal carbonate, metal oxychloride, and metal chloride. And condensates obtained by partially hydrolyzing them to form oligomers.

(Coating drying)
The upper layer and the lower layer of the lithographic printing plate material of the present invention can be formed by usually dissolving each of the above components in a solvent and sequentially applying the solution on a support. As the solvent used here, the following coating solvents can be used. These solvents are used alone or in combination.

(Coating solvent)
For example, n-propanol, isopropyl alcohol, n-butanol, sec-butanol, isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 2-ethyl-1-butanol 1-pentanol, 2-pentanol, 3-pentanol, n-hexanol, 2-hexanol, cyclohexanol, methylcyclohexanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 4-methyl 2-pentanol, 2-hexyl alcohol, benzyl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1,5-pentane glycol, dimethyltriglycol, fluoro Furyl alcohol, hexylene glycol, hexyl ether, 3-methoxy-1-butanol, 3-methoxy-3-methylbutanol, butylphenyl ether, ethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono Propyl ether, propylene glycol monobutyl ether, propylene glycol phenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, methyl carbitol, ethyl Carbitol, ethyl carbitol acetate Butyl carbitol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol dimethyl ether, diacetone alcohol, acetophenone, cyclohexanone, methylcyclohexanone, acetonyl acetone, isophorone, methyl lactate, ethyl lactate, butyl lactate, propylene carbonate , Phenyl acetate, acetic acid-sec-butyl, cyclohexyl acetate, diethyl oxalate, methyl benzoate, ethyl benzoate, γ-butyllactone, 3-methoxy-1-butanol, 4-methoxy-1-butanol, 3-ethoxy- 1-butanol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-ethyl-1-pentanol, 4-ethoxy-1-pentanol, 5-methoxy-1-hex Nord, 3-hydroxy-2-butanone, 4-hydroxy-2-butanone, 4-hydroxy-2-pentanone, 5-hydroxy-2-pentanone, 4-hydroxy-3-pentanone, 6-hydroxy-2-pentanone, Examples include 4-hydroxy-3-pentanone, 6-hydroxy-2-hexanone, 3-methyl-3-hydroxy-2-pentanone, methyl cellosolve (MC), and ethyl cellosolve (EC).

  As the solvent used for coating, it is preferable to select solvents having different solubility with respect to the alkali-soluble polymer used in the upper layer and the alkali-soluble polymer used in the lower layer. In other words, after applying the lower layer and then applying the upper heat-sensitive layer adjacent to it, if a solvent capable of dissolving the lower layer alkali-soluble polymer is used as the uppermost coating solvent, mixing at the layer interface is ignored. In an extreme case, it may become a uniform single layer rather than a multilayer. In this way, when mixing occurs at the interface between two adjacent layers, or when they are compatible with each other and behave like a uniform layer, the effects of the present invention due to having two layers may be impaired, which is not preferable. . For this reason, the solvent used for applying the upper heat-sensitive layer is preferably a poor solvent for the alkali-soluble polymer contained in the lower layer.

  In order to suppress mixing at the upper and lower layer interface, high-pressure air is blown from a slit nozzle installed substantially at right angles to the running direction of the web, or a roll (such as steam) supplied with a heating medium such as steam ( A method of drying the solvent very quickly after coating the second layer can be used by applying thermal energy as conduction heat from the lower surface of the web from the heating roll) or combining them.

  As a method of partially compatibility between the two layers at a level where the effects of the present invention are sufficiently exhibited, a method using the above-mentioned difference in solvent solubility, and drying the solvent very quickly after the second layer is applied In any method, the degree can be adjusted.

  The concentration of the above components (total solid content including additives) in the solvent when applying each layer is preferably 1 to 50% by mass.

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

  The drying temperature of the photosensitive layer is preferably in the range of 60 to 160 ° C, more preferably 80 to 140 ° C, and particularly preferably 90 to 120 ° C. In addition, an infrared radiation device can be installed in the drying device to improve drying efficiency.

  After the photosensitive layer is applied on a support and dried, an aging treatment may be performed to stabilize the performance. The aging treatment may be performed continuously with the drying zone or may be performed separately. The aging treatment may be used as a step of bringing a compound having an OH group into contact with the surface of the upper layer described in JP-A-2005-17599. In the aging process, by penetrating and diffusing a compound having a polar group typified by water from the surface of the formed photosensitive layer, the interaction with water is improved in the photosensitive layer, and heating is performed. Thus, the cohesive force can be improved, and the characteristics of the photosensitive layer can be improved.

  The temperature condition in the aging process is desirably set so that the compound to be diffused vaporizes more than a certain amount, and water is a typical example of the substance to be permeated and diffused. Any compound having a hydroxyl group, a carboxyl group, a ketone group, an aldehyde group, an ester group or the like can be suitably used. Such a compound is preferably a compound having a boiling point of 200 ° C. or lower, more preferably a compound having a boiling point of 150 ° C. or lower, preferably a boiling point of 50 ° C. or higher, more preferably 70 ° C. or higher. It is. The molecular weight is preferably 150 or less, and more preferably 100 or less.

(Active agent)
In the present invention, the upper layer and the lower layer are described in JP-A Nos. 62-251740 and 3-208514 in order to improve the coatability and to increase the stability of processing with respect to development conditions. Nonionic surfactants, amphoteric surfactants as described in JP-A-59-121044, JP-A-4-13149, and siloxane compounds as described in EP950517 Fluorine-containing monomer copolymers as described in JP-A-62-170950, JP-A-11-288093, and Japanese Patent Application No. 2001-247351 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 amphoteric activators 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.).

  As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable. 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. The proportion of the nonionic surfactant and amphoteric surfactant in the total solid content of the lower layer or upper layer is preferably 0.01 to 15% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.8. It is 05-0.5 mass%.

<Exposure development>
The lithographic printing plate material produced as described above is usually subjected to image exposure and development treatment and used as a lithographic printing plate.

  As a light source of light used for image exposure, a light source having a light emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable. Image exposure uses a commercially available setter for CTP, based on digitally converted data, after exposure with an infrared laser (830 nm), by processing such as development, an image is formed on the surface of the aluminum plate support, Can be provided as a lithographic printing plate.

  The exposure apparatus used in the plate making method is not particularly limited as long as it is a laser beam method, and any of a cylindrical outer surface (outer drum) scanning method, a cylindrical inner surface (inner drum) scanning method, and a flat (flat bed) scanning method may be used. However, in order to increase productivity by low-illumination long-time exposure, an outer drum type that is easy to be multi-beamed is preferably used, and an outer drum type exposure apparatus including a GLV modulation element is particularly preferable.

  In the exposure step, it is preferable to use a laser exposure recording apparatus equipped with a GLV modulation element to make it multichannel in order to improve the productivity of the lithographic printing plate. As the GLV modulation element, one that can divide a laser beam into 200 channels or more is preferable, and one that can divide a laser beam into 500 channels or more is more preferable. The laser beam diameter is preferably 15 μm or less, more preferably 10 μm or less. The laser output is preferably 10 to 100 W, more preferably 20 to 80 W. The drum rotation speed is preferably 20 to 300 rpm, and more preferably 30 to 200 rpm.

(Developer)
The developer and replenisher that can be applied to the lithographic printing plate material of the present invention have a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5.

As the developer (hereinafter referred to as a developer including a replenisher), a conventionally known alkaline aqueous solution can be used. For example, sodium hydroxide, ammonium, potassium and lithium are preferably used as the base. These alkali agents are used alone or in combination of two or more. Other examples include potassium silicate, sodium silicate, lithium silicate, ammonium silicate, potassium metasilicate, sodium metasilicate, lithium metasilicate, ammonium metasilicate, tripotassium phosphate, trisodium phosphate, trilithium phosphate, triammonium phosphate, phosphoric acid. Dipotassium, disodium phosphate, dilithium phosphate, diammonium phosphate, potassium carbonate, sodium carbonate, lithium carbonate, ammonium carbonate, potassium bicarbonate, sodium bicarbonate, lithium bicarbonate, ammonium bicarbonate, potassium borate, sodium borate, boric acid Lithium, ammonium borate and the like can be mentioned and may be added in the form of a preformed salt. Again, sodium hydroxide, ammonium, potassium and lithium can be added to the pH adjustment. 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 also used in combination. Most preferred are potassium silicate and sodium silicate. The concentration of silicate is ₂ to 4% by mass in terms of SiO ₂ concentration. Further, the molar ratio of SiO ₂ to alkali metal M (SiO ₂ / M) is more preferably in the range of 0.25 to ₂ .

  The developing solution referred to in the present invention is not only an unused solution used at the start of development, but also replenished to correct the activity of the solution that decreases due to processing of the infrared laser heat-sensitive lithographic printing plate material. The liquid is replenished and the liquid whose activity is maintained (so-called running liquid) is included.

  Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting developability, dispersing development residue, and improving ink affinity of the printing plate image area.

In addition to the above, the following additives can be added to the developer and replenisher, such as NaCl, KCl, KBr, etc. described in JP-A-58-75152. Salt, a complex such as [Co (NH ₃ )] ₆ Cl ₃ described in JP-A-59-121336, a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A-56-142258 And amphoteric polymer electrolytes, organometallic surfactants containing Si, Ti and the like described in JP-A-59-75255, organoboron compounds described in JP-A-59-84241, and the like.

  The developer and replenisher may further contain a preservative, a colorant, a thickener, an antifoaming agent, a hard water softening agent, and the like as necessary.

  In addition, it is advantageous in terms of transportation that the developer and the replenisher are concentrated solutions having a water content less than that in use and are diluted with water during use. The degree of concentration in this case is suitably such that each component does not separate or precipitate, but it is preferable to add a solubilizer if necessary. As the solubilizer, so-called hydrotropes such as toluenesulfonic acid, xylenesulfonic acid and alkali metal salts thereof described in JP-A-6-32081 are preferably used.

(Non-silicate developer)
For application to the development of the lithographic printing plate material of the present invention, a so-called “non-silicate developer” which does not contain an alkali silicate and contains a non-reducing sugar and a base can also be used. When this developer is used to develop the lithographic printing plate precursor, the surface of the recording layer is not deteriorated and the thickness of the recording layer can be maintained in a good state. In addition, the lithographic printing plate precursor 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.

  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 of a saccharide is bonded to a non-saccharide. 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.

  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 from the viewpoint of promoting high concentration and availability.

(Processing method)
As a plate making method for producing a printing plate from the planographic printing plate material of the present invention, it is preferable to use an automatic processor.

  The automatic processor used in the present invention is preferably provided with a mechanism for automatically replenishing a replenisher with a required amount in a developing bath, and preferably provided with a mechanism for discharging a developer exceeding a certain amount, Preferably, a mechanism for automatically replenishing a required amount of water to the developing bath is provided, preferably a mechanism for detecting plate passing is provided, and preferably the processing area of the plate based on detection of plate passing A mechanism for controlling the replenishment amount and / or replenishment timing of the replenisher and / or water to be replenished preferably based on detection of the plate and / or estimation of the processing area is provided. A mechanism for controlling the temperature of the developer, preferably a mechanism for detecting the pH and / or conductivity of the developer, preferably a pH and / or developer. Or electric Mechanism for controlling the replenishment amount and / or replenishment timing of replenishment solution and / or water tries to refill the original is given in degrees.

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

  The positive lithographic printing plate material developed with the developer having the above composition is washed with water, a rinse solution containing a surfactant, etc., and a finisher or protective gum solution mainly composed of gum arabic or starch derivatives. Processed. For the post-treatment of the positive-type planographic printing plate material of the present invention, these treatments can be used in various combinations. For example, post-development-water-wash-surfactant-containing rinse treatment or development-water-wash-finisher solution The treatment by is preferable because there is little fatigue of the rinsing liquid and finisher liquid.

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

(Burning process)
The printing plate obtained by making a plate is subjected to a burning treatment as desired in order to obtain a higher printing durability lithographic printing plate.

  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 subjected to the burning treatment can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound or the like was used. In some cases, 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.

(Wrapping material-slip paper)
In the lithographic printing plate material of the present invention, after applying and drying the surface layer, in order to prevent mechanical shock during storage or to reduce unnecessary shock during transportation, a slip sheet is inserted between the printing plates, Storage, storage, transportation, etc. are preferably performed. Various slip sheets can be selected and used as appropriate.

  In general, a low-cost raw material is often selected for the interleaving paper in order to suppress material costs. For example, paper using 100% wood pulp, paper using synthetic pulp mixed with wood pulp, In addition, paper having a low density or high density polyethylene layer on the surface thereof can be used. In particular, a paper that does not use a synthetic pulp or a polyethylene layer has a low material cost, so that a slip sheet can be produced at a low cost.

Among the specifications of the slip sheets described above, preferable specifications include a basis weight of 30 to 60 g / m ² , a smoothness of 10 to 100 seconds according to a Beck smoothness measuring method defined in JIS 8119, and a moisture content of JIS 8127. It is 4 to 8% and density is 0.7 to 0.9 g / cm ³ according to the specified moisture content measurement method. In order to absorb the residual solvent, it is preferable that at least the surface in contact with the photosensitive layer is not laminated with a polymer or the like.

(printing)
Printing can be performed using a general lithographic printing machine.

  In recent years, the printing industry has been screaming for environmental protection, and in printing inks, inks that do not use petroleum-based volatile organic compounds (VOC) have been developed and are becoming popular. This is particularly noticeable when the printing inks are used. Examples of environmentally friendly printing inks include soybean oil ink “Naturalis 100” manufactured by Dainippon Ink and Chemicals, VOC zero ink “TK Hi-Echo NV” manufactured by Toyo Ink, and process ink “Soyselbo” manufactured by Tokyo Ink. It is done.

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

“Preparation of support 1”
A 0.3 mm thick aluminum plate (material 1050, tempered H16) was degreased with a 5% aqueous sodium hydroxide solution maintained at 65 ° C. for 1 minute, washed with water, and maintained at 25 ° C. 10 It was immersed in a 1% aqueous sulfuric acid solution for 1 minute, neutralized, and further washed with water. The aluminum plate was subjected to electrolytic surface roughening with an alternating current in a 1.0% by mass nitric acid aqueous solution at a temperature of 25 ° C., a current density of 10 A / dm ² , and a treatment time of 60 seconds.

Next, desmutting is performed in a 5% aqueous sodium hydroxide solution at a temperature of 60 ° C. for 10 seconds, and then anodizing is performed in a 20% sulfuric acid solution at a temperature of 20 ° C., a current density of 3 A / dm ² , and a processing time of 1 minute. Went. Then, it was immersed in 1% ammonium acetate aqueous solution kept at 80 ° C. for 30 seconds, washed with water and dried at 80 ° C. for 3 minutes. Further, the substrate 1 was dipped in an aqueous solution (concentration: 0.1% by mass) of carboxymethyl cellulose (hereinafter abbreviated as CMC) kept at 85 ° C. for 30 seconds, and then dried at 80 ° C. for 5 minutes to prepare a support 1.

(Synthesis of novolac resin)
A 300 ml separable flask was charged with 3.48 g of phenol, 45.84 g of metacresol, 30.56 g of paracresol, 32.1 g of formalin (37% aqueous solution) and 0.16 g of oxalic acid, and placed in an oil bath at 110 ° C. for 3 hours. The reaction was conducted by heating and stirring, and the product was dried under reduced pressure to obtain a novolak resin. The weight average molecular weight of the resin thus obtained was 3700.

(Synthesis of acid-decomposable compound 1)
58 g of 1,1-dimethoxycyclohexane, 85 g of diethylene glycol, 194 mg of p-toluenesulfonic acid and 200 ml of toluene were mixed and reacted for 11 hours while stirring at 120 ° C. After completion of the reaction, methanol and reaction solvent produced by the reaction were removed, washed with 200 ml of water, washed with 400 ml of 1% sodium hydroxide aqueous solution, and then washed with saturated saline until neutral. The obtained compound was dehydrated with anhydrous potassium carbonate and then distilled under reduced pressure to obtain acid-decomposable compound 1.

(Synthesis of copolymer)
Copolymers C1 to C13 shown in Table 1 were synthesized using the monomers shown in Table 1. The numerical values in the table represent the molar ratio of monomers.

(Method of synthesizing copolymer)
In a 100 ml three-necked flask equipped with a stirrer, a condenser tube and a dropping funnel, the monomers described in Table 1 are added so as to have a total molar ratio of 9 g, and 20 g of N, N-dimethylacetamide is added. The mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of “V-65 (2,2′-azobis (2,4 dimethylvaleronitrile))” (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was kept under a nitrogen stream for 2 hours while maintaining at 65 ° C. Stir. The same amount of the same monomer as above, and a mixture of 20 g of N, N-dimethylacetamide and 0.15 g of “V-65” were added dropwise to the reaction mixture through a dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, 40 g of methanol was added to the mixture, cooled, and the resulting mixture was poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was removed by filtration and dried. A white solid as a copolymer was obtained.

(Preparation of lithographic printing plate materials)
A lower layer-1 coating solution having the following composition is coated on the support 1 with a wire bar so that the dry mass becomes 0.8 g / m ² and dried in a 95 ° C. atmosphere for 90 seconds to obtain a lithographic printing plate material 1 It was.

On the lower layer of the lithographic printing plate material 1, an upper layer-1 coating solution having the following composition is applied with a wire bar so that the dry mass is 0.8 g / m ^2, and is dried in an atmosphere at 95 ° C. for 90 seconds. Material 2 was obtained.

On the lower layer of the lithographic printing plate material 1, an upper layer-2 coating solution having the following composition is applied with a wire bar so that the dry mass becomes 0.8 g / m ^2, and is dried in a 95 ° C. atmosphere for 90 seconds. Material 3 was obtained.

  Lithographic printing plate materials 4 to 16 were obtained in the same manner as the lithographic printing plate material 3 except that the lower layer and upper layer coating solutions were changed to those shown in Table 1.

(Lower layer-1 coating solution)
Infrared absorber (IR25) 1 part by weight Acid generator ((III) -1) 3 parts by weight Acid-decomposable compound 1 20 parts by weight Novolak resin 76 parts by weight Propylene glycol monomethyl ether 700 parts by weight Methyl ethyl ketone 300 parts by weight (Lower layer-2 Coating liquid)
Infrared absorber (IR25) 1 part by weight Acid generator ((III) -1) 3 parts by weight Acid-decomposable compound 1 20 parts by weight Novolak resin 11 parts by weight Copolymer (C1) shown in Table 1 65 parts by weight Propylene glycol monomethyl 700 parts by mass of ether 300 parts by weight of methyl ethyl ketone (lower layer-3-14 coating solution)
The copolymer of Lower layer-2 was prepared in the same manner as Lower layer-2 except that the copolymer was changed as shown in Table 2.

(Upper layer-1 coating solution)
Novolac resin KNC-1 (m / p = 6/4, molecular weight 4880: manufactured by Sumitomo Bakelite Co., Ltd.) 88.0 parts by mass Infrared absorbing dye 6.0 parts by mass Visible agent: Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.5 parts by mass Fluorosurfactant: Megafac F-178K (Dainippon Ink Chemical Co., Ltd.)
1.0 part by mass Solvent: methyl ethyl ketone / 1-methoxy-2-propanol (1/2)
903.0 parts by mass (upper layer-2 coating solution)
Novolak resin KNC-1 (m / p = 6/4, molecular weight 4880: manufactured by Sumitomo Bakelite Co., Ltd.) 23.0 parts by mass Copolymer (C1) shown in Table 1 65.0 parts by mass Infrared absorbing dye 6.0 parts by mass Visible paint agent: Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.) 0.5 parts by mass Fluorosurfactant: MegaFac F-178K (Dainippon Ink Chemical Co., Ltd.)
1.0 part by mass Solvent: methyl ethyl ketone / 1-methoxy-2-propanol (1/2)
903.0 parts by mass

(Exposure, development)
PTR-4300 manufactured by Dainippon Screen Mfg. Co., Ltd. is used as the lithographic printing plate materials 1-16, the drum rotation speed is 1000 rpm, the laser output is 100 mJ / cm ² , and the resolution is 1200 dpi (dpi is a dot per 2.54 cm) 3% dot, 50% dot, and solid image were exposed. The exposed plate was subjected to development processing at 30 ° C. for 15 seconds using a developing solution of an automatic developing machine (manufactured by Raptor 85 Thermal GLUNZ & JENSEN) and PD-1 (Kodak Polychrome).

<Evaluation>
(Developability)
The non-image area of the developed printing plate was measured using a densitometer (X-Rite 528). Set the measurement color to cyan and measure the density. A concentration of 0.40 or less is a practical range.

(Print life)
The planographic printing plate material was printed under the following conditions. The printing plate material was attached to the plate cylinder as it was after exposure, and printed using the same printing sequence as the PS plate. For evaluation of printing durability, a 3% halftone image was observed with a magnifying glass, and the stage where 30% of the dots disappeared as the end point of printing durability.

Printing machine: DAIYA F-1 manufactured by Mitsubishi Heavy Industries, Ltd.
Printing paper: Kinmari SW
Printing speed: 9,000 sheets / hour Dampening solution: 2% by weight aqueous solution of Astro Mark 3 (manufactured by Nikken Chemical Laboratory) Ink: (TK High Unity Red, manufactured by Toyo Ink)
The results are shown in Table 2. From Table 2, it can be seen that the planographic printing plate material of the present invention has good developability and sufficient printing durability.

Claims (2)

A positive photosensitive material having an image forming layer lower layer containing an alkali-soluble resin, an acid-decomposable compound and an acid generator on an aluminum support, and an image forming layer upper layer containing an alkali-soluble resin on the image forming layer lower layer. A lithographic printing plate material, wherein the lower layer of the image forming layer contains a copolymer containing a repeating unit represented by the following general formula (1) as the alkali-soluble resin: Printing plate material.

(In the formula, A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, X represents an alkylene group, and Y represents a carboxyl group or a group having a base thereof, a sulfo group or a salt thereof, a phosphonoxy group, a dialkylphospho group. Represents a nonoxy group, a trialkoxysilyl group, or an alkyldialkoxysilyl group.) 2. The positive photosensitive lithographic printing plate material according to claim 1, wherein X is an ethylene group.