JP4997201B2 - Preparation method of lithographic printing plate - Google Patents

Description

  The present invention relates to a method for preparing a lithographic printing plate. More specifically, the present invention relates to a method for producing a lithographic printing plate suitable for suppressing re-deposition of the plate surface of the development removal component and obtaining good printing performance.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image forming layer) is provided on a hydrophilic support has been widely used. Usually, after exposing the lithographic printing plate precursor through an original image such as a lithographic film, the image forming layer corresponding to the image portion is left, and the unnecessary image forming layer corresponding to the non-image portion is adjusted to pH 12 or more. The lithographic printing plate is obtained by dissolving and removing with a strong alkaline developer or an organic solvent-containing developer and exposing the surface of the hydrophilic support to form a non-image area.

  In the conventional lithographic printing plate preparation process, after the exposure, a step of dissolving and removing unnecessary image forming layers with a developer or the like is necessary. To simplify such additional wet processing, Is listed as one of the issues. In particular, disposal of the waste liquid discharged with high pH alkaline development processing has become a major concern for the entire industry in recent years due to consideration for the global environment. It is more strongly desired to be able to develop with an aqueous solution.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Therefore, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

When the simplified plate making operation as described above is performed in a printing environment, the image forming layer after exposure may be covered in the bright room of the printing environment before development. There is a need for an imaging layer and a light source that can be handled under the light.
As such a laser light source, a solid-state laser such as a semiconductor laser and a YAG laser that emits infrared light having a wavelength of 760 to 1200 nm is extremely useful because a high-power and small-sized laser can be obtained at low cost. A UV laser can also be used.

  From the background as described above, it is now more strongly desired than ever to adapt both the simplification of the plate making operation and the digitization.

On the other hand, for example, in Patent Document 1, a lithographic printing plate precursor in which an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support is used as a gum solution. A plate making method for development is described. In this plate making method, the lithographic printing plate precursor is subjected to image exposure using an infrared laser to form an image by fusing hydrophobic thermoplastic polymer particles, and then the unexposed portion is removed with a gum solution. By developing.
However, the method of developing a lithographic printing plate precursor using image formation by thermal fusion of such fine particles with a gum solution has very good developability but low sensitivity and printing durability, and is unexposed. Since the removed fine particles are likely to aggregate and settle in the developer, there has been a problem that the development removal component reattaches to the plate surface after the development treatment and ink stains occur on the printed matter.

Patent Document 2 discloses a lithographic printing plate precursor comprising a photosensitive layer containing (i) a hydrophilic support and (ii) a radical polymerizable ethylenically unsaturated monomer, a radical polymerization initiator and an infrared absorbing dye. A method for processing a lithographic printing plate precursor is described in which an uncured portion of the photosensitive layer is removed with a gum solution after imagewise exposure with an external laser. Patent Document 3 describes a method for developing a lithographic printing plate precursor comprising curing a radical polymerization type photosensitive layer by infrared laser exposure and removing an unexposed portion with an aqueous developer having a pH of 2 to 10. . These use radical polymerization for image formation and have high sensitivity, but because no polymer particles are used in the photosensitive layer, the developability is poor, and the halftone dots in the shadow area are poor, resulting in poor halftone dot reproducibility. was there.
In Patent Document 4, a radical polymerization image forming layer containing polymer binder particles containing a unit having a cyano group in the side chain and a unit having a polyalkylene oxide segment in the side chain is imaged by an infrared laser or the like. A method for preparing a lithographic printing plate is described which comprises exposing to light and developing with an aqueous solution having a pH of about 5 to about 14 or on-press development.
However, the above technique still has the problem that the polymer particles after removal of development aggregate and settle in the processing liquid and re-adhere to the plate surface after the development processing to cause ink stains on the printed matter.

European Patent No. 1342568 International Publication No. 05/111727 Pamphlet US Pat. No. 6,902,865 U.S. Pat. No. 7261998

  Accordingly, an object of the present invention is to provide a method for preparing a lithographic printing plate suitable for suppressing re-deposition of the plate surface of the development-removed component and obtaining good fine line reproducibility while maintaining good developability. It is in.

As a result of various studies to solve the above-mentioned problems, the present inventor contains, as polymer particles in the image forming layer, a repeating unit having a polyalkylene oxide segment in the side chain and a repeating unit having a cyano group in the side chain. The present inventors have found that the above-mentioned problems can be solved by using polymer fine particles to be used and using an aqueous solution containing carbonate ions and hydrogen carbonate ions as a treatment liquid.
That is, the present invention is as follows.

(1) A method for preparing a lithographic printing plate comprising an image forming layer comprising a polymer fine particle containing a repeating unit having a polyalkylene oxide segment in a side chain and a repeating unit having a cyano group in a side chain on a support A method for preparing a lithographic printing plate comprising the following steps (a) and (b):
(A) A step of exposing the lithographic printing plate precursor imagewise.
(B) A step of developing the exposed lithographic printing plate precursor with an aqueous solution of pH 8.5 to 10.5 containing carbonate ions and hydrogen carbonate ions.
(2) The method for preparing a lithographic printing plate as described in (1) above, wherein the aqueous solution used in the developing step (b) further contains a water-soluble polymer compound.
(3) The method for preparing a lithographic printing plate as described in (2) above, wherein the water-soluble polymer compound is gum arabic or starch.
(4) The method for preparing a lithographic printing plate as described in any one of (1) to (3) above, wherein the aqueous solution used in the developing step (b) further contains a surfactant.
(5) The lithographic printing plate as described in any one of (1) to (4) above, wherein the developing step (b) is performed using an automatic processor having a rubbing member. Method.
(6) The method for preparing a lithographic printing plate as described in any one of (1) to (5) above, wherein the development step (b) is continuously performed twice or more.
(7) After the developing step (b), the method further includes (c) a step of washing the developed lithographic printing plate precursor surface with water, as described in any one of (1) to (6) above. A method for preparing a lithographic printing plate.
(8) The method for preparing a lithographic printing plate as described in any one of (1) to (7) above, wherein the aqueous solution used in the developing step (b) is repeatedly used through a filter. (9) The image forming layer further contains (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound, and the exposure step (a) is performed by laser irradiation. The method for producing a lithographic printing plate according to any one of (1) to (8) above.
(10) The lithographic printing plate as described in (9) above, wherein (A) the sensitizing dye is a water-soluble cyanine dye, and (B) the polymerization initiator is a water-soluble onium salt. Manufacturing method. (11) The lithographic printing plate precursor has a protective layer on the image forming layer, and the protective layer contains 10 to 50% by mass of anion-modified polyvinyl alcohol in the total solid content of the protective layer. The method for producing a lithographic printing plate according to any one of (1) to (10) above.
(12) The lithographic printing plate precursor includes an undercoat layer between the support and the image forming layer, and the undercoat layer contains a compound having a substrate adsorptive group and a crosslinkable group in the molecule. The method for producing a lithographic printing plate according to any one of the above (1) to (11), which is characterized in that
(13) The method for preparing a lithographic printing plate as described in any one of (1) to (12) above, wherein the support is an anodized support using phosphoric acid.
(14) The method for preparing a lithographic printing plate as described in any one of (1) to (13) above, wherein the support is a support hydrophilized using polyvinylphosphonic acid. .

  According to the present invention, after image exposure, it is not necessary to use a high pH alkaline development treatment, and while maintaining good developability in a processing solution close to neutrality, it is possible to suppress the plate surface re-adhesion of the development removal component, In addition, a method for producing a lithographic printing plate suitable for obtaining good fine line reproducibility can be provided.

[Plate making method]
In the method for producing a lithographic printing plate of the present invention, after imagewise exposure, removal (development) of the unexposed portion of the image forming layer is performed using an aqueous solution containing carbonate ions and hydrogen carbonate ions (hereinafter also referred to as a processing solution). It is characterized by performing.
The processing liquid preferably contains a water-soluble polymer compound or a surfactant, and in particular, by containing a water-soluble polymer compound, desensitization of the non-image area after removing the image forming layer simultaneously with development. Processing can be performed.

(Processing liquid)
The treatment liquid used in the method for producing a lithographic printing plate of the present invention is an aqueous solution having a pH of 8.5 to 10.5 containing carbonate ions and hydrogen carbonate ions. In order for carbonate ions and bicarbonate ions to be present in the developer, carbonate and bicarbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more. The pH of the treatment liquid needs to be in the above range. When the pH is less than 8.5, the developability of the non-image area is lowered.

  1-20 mass% is preferable with respect to the mass of alkaline aqueous solution, and, as for the total amount of carbonate and hydrogencarbonate, 3-15 mass% is more preferable, and 4-12 mass% is the most preferable. If the total amount is 1% by mass or more, developability and processing capacity do not decrease, and if it is 20% by mass or less, it becomes difficult to form precipitates and crystals, and further, it becomes difficult to gel during neutralization during waste liquid treatment, Does not interfere with waste liquid treatment.

  Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the non-image area photosensitive layer, another alkali agent such as an organic alkali agent may be supplementarily used together. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. These other alkali agents are used alone or in combination of two or more.

  Examples of the water-soluble polymer compound used in the aqueous solution in the development process of the present invention include soybean polysaccharide, starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, Examples include polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like. .

  A preferable acid value of the water-soluble polymer compound is 0 to 3.0 meq / g.

  As said soybean polysaccharide, what is known conventionally can be used, for example, there is Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  Examples of the starch include candy starch, potato starch, tapioca starch, wheat starch and corn starch, and these modified starches and starch derivatives. As modified starch, what is shown by the following general formula (III) is preferable.

  In formula (III), the degree of etherification (degree of substitution) is in the range of 0.05 to 1.2 per glucose unit, n represents an integer of 3 to 30, and m represents an integer of 1 to 3.

  The modified starch can be produced by, for example, a method in which starch is decomposed with an acid or an enzyme in the range of 5 to 30 glucose residues per molecule and oxypropylene is added in an alkali.

  As starch derivatives, roasted starch such as British gum, enzyme-modified dextrins such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, pregelatinized starch such as modified pregelatinized starch and non-modified pregelatinized starch, Esterified starch such as phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch and carbamic acid starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl Starch, etherified starch such as dialkylamino starch, methylol cross-linked starch, hydroxyalkyl cross-linked starch, phosphoric acid cross-linked starch, cross-linked starch such as dicarboxylic acid cross-linked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer, starch Polyacetic acid Nyl copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylic acid ester copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, starch polypropylene copolymer Starch graft polymers such as polymers are preferred.

  Among the water-soluble polymer compounds, soybean polysaccharides, starch, gum arabic, dextrin, carboxymethyl cellulose, polyvinyl alcohol and the like are preferable. More preferably, gum arabic or starch is used.

  Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the treatment liquid is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

The treatment liquid of the present invention may contain a surfactant (anionic, nonionic, cationic, amphoteric, etc.).
Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates , Sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid compounds Glyceryl sulfate ester salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene -Partial saponification products of maleic anhydride copolymer, partial saponification products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, aromatic sulfonates, aromatic substituted polyoxyethylene sulfonic acid Examples include salts. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, polyethylene glycol adducts of aromatic compounds, fatty acid ethylene oxide adducts, and polyhydric alcohol fatty acid esters. Ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene Oxide) block copolymer, etc., polyhydric alcohol type glycerol fatty acid ester, pentaerythritol Fatty acid esters, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the treatment liquid of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.

  The amphoteric surfactant used in the present invention is a compound having an anionic site and a cationic site in the same molecule, as is well known in the field of surfactants, and includes amino acids, betaines, amine oxides. Amphoteric surfactants such as systems are included. As the amphoteric surfactant used in the treatment liquid according to the present invention, a compound represented by the following formula <1> and a compound represented by the following formula <2> are preferable.

In formula <1>, R8 represents an alkyl group, R9 and R10 each represent a hydrogen atom or an alkyl group, R11 represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion.
In formula <2>, R18, R19 and R20 each represent a hydrogen atom or an alkyl group. However, not all of R18, R19 and R20 are hydrogen atoms.

In the above formula <1>, the alkyl group represented by R8, R9 or R10 and the alkylene group represented by R11 may be linear or branched, and may have a linking group in the chain. Moreover, it may further have a substituent. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <1>, when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in an aqueous developer. In this case, it is improved by adding a solubilizing agent such as an organic solvent such as alcohol, but when the total carbon number becomes too large, the surfactant cannot be dissolved within the proper mixing range. There is a case. Therefore, the total number of carbon atoms of R8 to R11 is preferably 8 to 25, and more preferably 11 to 21.

In the above formula <2>, the alkyl group represented by R18, R19 or R20 may be linear or branched, may have a linking group in the chain, and further has a substituent. You may do it. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <2>, when the total carbon number is increased, the hydrophobic portion is increased and it is difficult to dissolve in an aqueous developer. In this case, it is improved by adding a solubilizing agent such as an organic solvent such as alcohol, but when the total carbon number becomes too large, the surfactant cannot be dissolved within the proper mixing range. There is a case. Therefore, the total number of carbon atoms of R18 to R20 is preferably 8 to 22, and more preferably 10 to 20.

  The total carbon number of the amphoteric surfactant may be affected by the material used for the photosensitive layer, particularly the properties of the binder. In the case of a binder having a high degree of hydrophilicity, those having a relatively small total carbon number are preferred, and when the binder used has a low degree of hydrophilicity, those having a large total carbon number tend to be preferred.

  Surfactants can be used alone or in combination. The content of the surfactant in the treatment liquid is preferably 0.01 to 10% by mass, and more preferably 0.01 to 5% by mass.

  In addition to the above, the treatment liquid of the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, organic solvent, inorganic acid, inorganic salt, and the like.

  As the wetting agent, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin and the like are preferably used. The wetting agent may be used alone or in combination of two or more. Generally, the wetting agent is used in an amount of 0.1 to 5% by weight based on the total weight of the treatment liquid.

Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benztriazole derivatives Amiding anidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1, 1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used. It is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization.
The content of the preservative is an amount that exhibits a stable effect on bacteria, mold, yeast, and the like, and varies depending on the type of bacteria, mold, yeast, but 0.01 to 4 relative to the treatment solution. A range of mass% is preferred.

Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.
A chelating agent is selected that is stably present in the treatment liquid and does not impair the printability. The content is preferably 0.001 to 1.0 mass% with respect to the treatment liquid.

As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.
The content of the antifoaming agent is preferably in the range of 0.001 to 1.0% by mass with respect to the treatment liquid.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content of the organic acid is preferably 0.01 to 0.5% by mass with respect to the treatment liquid.

  Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). And xylene), halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), and polar solvents.

  Polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether , Propylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.) , (Acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene Glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the treatment liquid contains an organic solvent, the concentration of the solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content of the inorganic salt is preferably 0.01 to 0.5% by mass with respect to the treatment liquid.

  The development processing of the present invention is preferably carried out using an automatic processor equipped with a rubbing member. Further, the development processing of the present invention can be preferably carried out by an automatic processor equipped with a supply means such as the processing liquid of the present invention. Examples of the automatic processor include an automatic processor described in JP-A No. 2006-235227 and the like that performs rubbing while conveying a lithographic printing plate precursor after image recording. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

The rotating brush roll that can be preferably used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness of the lithographic printing plate precursor support.
As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, a metal or plastic grooved material in which brush materials are implanted in a row, such as those described in JP-A-58-159533, JP-A-3-100554, or JP-A-62-167253 A brush roll can be used in which the core is radially wound around a plastic or metal roll with no gap.
Examples of brush materials include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylics such as polyacrylonitrile and poly (meth) acrylate). , And polyolefin-based synthetic fibers such as polypropylene and polystyrene). For example, fiber diameters of 20 to 400 μm and hair lengths of 5 to 30 mm can be suitably used. .
The outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec.

  The rotating direction of the rotating brush roll may be the same or opposite to the conveying direction of the lithographic printing plate precursor. However, when two or more rotating brush rolls are used, at least one rotating brush roll is used. Preferably, the rotating brush rolls rotate in the same direction, and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the image forming layer in the unexposed area. It is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  In the method for preparing a lithographic printing plate of the present invention, a method in which the development step (b) is continuously performed twice or more is also preferable. As a specific method for continuously performing such development processing twice or more, the development processing is performed twice using an automatic processor (see FIG. 2) including only the developing section having the rubbing member as described above. A method of repeating the above (in this case, two or more automatic processors may be connected), a method of using an automatic processor having a plurality of developing units equipped with a rubbing member as described above, etc. Can be mentioned.

As another preferred embodiment of the method for producing a lithographic printing plate of the present invention, a water washing step can be performed following the development step using the processing solution of the present invention. By carrying out the above-described continuous development and water washing steps, re-deposition of the plate surface of the development removal component is further suppressed.
The water used in the water washing step of the present invention can be any water such as general tap water, well water, ion-exchanged water, and distilled water. However, tap water and well water are preferable from the economical viewpoint. It is preferable that the water used in the washing step is always fresh water or reused by circulating the water used in the washing step through a filter as described later.

  As the processing solution of the present invention, a fresh solution may always be used, but it is preferable to repeatedly use the processing solution after the development processing by circulating it through a filter.

Any filter can be used for the processing solution used in the development step and the water washing step of the present invention and the filter used for filtering water as long as the image forming layer removing component mixed in each solution can be filtered. As a material for the filter, polyester resin, polypropylene resin, polyethylene resin, cellulose resin, cotton, or the like is preferably used. In addition, as the form, a filter that is accommodated in the form of a cartridge in a housing as a replaceable filter is preferable. The cartridge is made of, for example, a filter paper made of cellulose fiber, processed with an epoxy resin for reinforcing the strength and preventing the fiber from coming off, and a pleat type molded into a pleat shape to increase the filtration area. The adsorbent is housed in a depth type or a plastic case such as polyethylene that is rolled up so that a gentle density gradient can be obtained from the center tube, or is mainly composed of resin, cellulose, glass fiber and water-absorbing polymer An adsorption type in which an adsorbent such as activated carbon is supported on the prepared media is preferable. The adsorbent was selected from silica gel, activated carbon, activated aluminum, molecular sieve, clay and superabsorbent fiber, calcium carbonate, calcium sulfate, potassium permanganate, sodium carbonate, potassium carbonate, sodium phosphate and active metal. Materials and ion exchangers used for various filters can be used.
As available filters, cartridge filters “TCW type”, “TCP type”, “TCS type” manufactured by ADVANTEC are preferably used.
The mesh diameter of the filter is preferably 5 to 500 μm, more preferably 10 to 200 μm, and still more preferably 20 to 100 μm.

  The developing solution and the desensitizing treatment are simultaneously performed using the processing solution of the present invention, followed by a drying treatment. Moreover, when the water washing process is performed after the image development process using the processing liquid of this invention, it is also possible to perform the desensitization process of the non-image part by a gum solution further after that.

  By supplying the gum solution to the plate surface after the water washing step, the non-image area can be sufficiently desensitized. In this desensitization step, an aqueous solution containing a water-soluble polymer compound among general gum solution and the above-described treatment solution of the present invention is used. In the latter case, it is preferable in view of the apparatus structure to use a liquid having basically the same composition as the processing liquid of the present invention used in the development processing step. This means that the processing liquid of the present invention charged in the tank of the developing unit and the liquid charged in the tank of the desensitizing unit are the same. It does not mean that the composition changes due to contamination of the original plate components, further evaporation of water or dissolution of carbon dioxide. As a result, it is possible to make common the charge liquid and replenisher used in each process. Furthermore, a cascade system in which the necessary amount of the replenisher for the developing unit is supplied by overflowing the circulating liquid of the desensitizing unit can be adopted.

The gum solution used for the desensitization process after the water washing process in this invention is demonstrated.
The desensitizing agent used in the gum solution is preferably gum arabic, and an aqueous solution of about 15 to 20% by mass of gum arabic can be used as the gum solution. In addition to gum arabic, various water-soluble resins are used as a desensitizing agent. For example, water-soluble polysaccharides extracted from dextrin, steravic, structan, alginates, polyacrylates, hydroxyethylcellulose, polyvinylpyrrolidone, polyacrylamide, methylcellulose, hydroxypropylcellulose, hydroxymethylcellulose, carboxyalkylcellulose salts, soybean okara In addition, pullulan or pullulan derivatives and polyvinyl alcohol are also preferable.

  Furthermore, as modified starch derivatives, roasted starch such as British gum, enzyme-modified dextrins such as enzyme dextrin and shardinger dextrin, oxidized starch shown in solubilized starch, alpha-modified starch such as modified pregelatinized starch and non-modified pregelatinized starch Esterified starch such as phosphate starch, fat starch, sulfate starch, nitrate starch, xanthate starch and carbamic acid starch, carboxyalkyl starch, hydroxyalkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamyl Etherified starch such as ethyl starch and dialkylamino starch, methylol crosslinked starch, hydroxyalkyl crosslinked starch, phosphoric acid crosslinked starch, crosslinked starch such as dicarboxylic acid crosslinked starch, starch polyacrylamide copolymer, starch polyacrylic acid copolymer, starch Vinyl acetate copolymer, starch polyacrylonitrile copolymer, chaotic starch polyacrylic acid ester copolymer, chaotic starch vinyl polymer copolymer, starch polystyrene maleic acid copolymer, starch polyethylene oxide copolymer, starch Starch graft polymers such as polypropylene copolymers are preferred.

  Natural polymer compounds include starches such as candy starch, potato starch, tapioca starch, wheat starch and corn starch, carrageenan, laminaran, seaweed mannan, funari, Irish moss, agar and algae such as sodium alginate. , Plant mucilage such as troroaoy, mannan, quince seed, pectin, tragacanth gum, karaya gum, xanthine gum, guar bin gum, locust bin gum, carob gum, benzoin gum, homopolysaccharides such as dextran, glucan, levan and saxino glucan and santang gum Proteins such as microbial mucilage such as hetropolysaccharide, glue, gelatin, casein and collagen are preferred.

  Two or more water-soluble resins can be used in combination, and can be contained in the gum solution in an amount of preferably 1 to 50% by mass, more preferably 3 to 30% by mass.

  The gum solution may contain a pH adjuster, surfactant, preservative, antifungal agent, lipophilic substance, wetting agent, chelating agent, antifoaming agent and the like in addition to the above desensitizing agent.

  The gum solution is advantageously used in a pH range of 3 to 12, and therefore a pH adjuster is generally added. In order to adjust the pH to 3 to 12, generally, a mineral acid, an organic acid or an inorganic salt is added to the gum solution and adjusted. The addition amount is 0.01-2 mass%. For example, the mineral acid includes nitric acid, sulfuric acid, phosphoric acid, metaphosphoric acid and the like. Examples of the organic acid include acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, levulinic acid, phytic acid, organic phosphonic acid, polystyrene sulfonic acid, and amino acids such as glycine, α-alanine, and β-alanine. Inorganic salts include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, nickel sulfate, sodium hexametaphosphate, sodium tripolyphosphate, and the like. You may use together 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

Examples of the surfactant contained in the gum solution include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, α-olefin sulfonic acid salts, dialkyl sulfosuccinic acid salts, alkyl diphenyl ether disulfonic acid salts, linear alkyl benzene sulfonic acid salts, branched Chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurate, disodium N-alkylsulfosuccinate monoamide Salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxy Ethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene Examples thereof include alkyl phenyl ether phosphate esters, saponification products of styrene-maleic anhydride copolymers, partial saponification products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, alkyl naphthalene sulfonates, α-olefin sulfonates, and alkyl diphenyl ether disulfonates are particularly preferably used.

  As the cationic surfactant, alkylamine salts, quaternary ammonium salts and the like are used.

  As the amphoteric surfactant, alkyl carboxybetaines, alkyl imidazolines, alkylaminocarboxylic acids and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial esters, sorbitan fatty acid partial esters , Pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters , Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanol Mido, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamine, triethanolamine fatty acid ester, trialkylamine oxide, polypropylene glycol molecular weight 200-5000, trimethylolpropane, glycerin or sorbitol poly Examples include adducts of oxyethylene or polyoxypropylene, and acetylene glycols. Fluorine-based and silicon-based nonionic surfactants can also be used in the same manner.

  Two or more surfactants can be used in combination. The amount used is not particularly limited, but a preferable range is 0.01 to 20% by mass, preferably 0.05 to 10% by mass based on the total mass of the gum solution.

  As the preservative, known preservatives used in the fields of fiber, wood processing, food, medicine, cosmetics, agricultural chemicals and the like can be used. For example, quaternary ammonium salts, monohydric phenol derivatives, dihydric phenol derivatives, polyhydric phenol derivatives, imidazole derivatives, pyrazolopyrimidine derivatives, monovalent naphthols, carbonates, sulfone derivatives, organotin compounds, cyclopentane derivatives, phenyl derivatives , Phenol ether derivatives, phenol ester derivatives, hydroxylamine derivatives, nitrile derivatives, naphthalenes, pyrrole derivatives, quinoline derivatives, benzothiazole derivatives, secondary amines, 1,3,5 triazine derivatives, thiadiazole derivatives, anilide derivatives, pyrrole derivatives , Halogen derivatives, dihydric alcohol derivatives, dithiols, cyanic acid derivatives, thiocarbamic acid derivatives, diamine derivatives, isothiazole derivatives, monohydric alcohols, saturated aldehydes, Japanese monocarboxylic acid, saturated ether, unsaturated ether, lactone, amino acid derivative, hydantoin, cyanuric acid derivative, guanidine derivative, pyridine derivative, saturated monocarboxylic acid, benzenecarboxylic acid derivative, hydroxycarboxylic acid derivative, biphenyl, hydroxamic acid derivative , Aromatic alcohols, halogenophenol derivatives, benzenecarboxylic acid derivatives, mercaptocarboxylic acid derivatives, quaternary ammonium salt derivatives, triphenylmethane derivatives, hinokitiol, furan derivatives, benzofuran derivatives, acridine derivatives, isoquinoline derivatives, arsine derivatives, thiocarbamine Acid derivatives, phosphate esters, halogenobenzene derivatives, quinone derivatives, benzenesulfonic acid derivatives, monoamine derivatives, organophosphate esters, piperazine derivatives , Phenazine derivatives, pyrimidine derivatives, thiophanate derivatives, imidazoline derivatives, isoxazole derivatives, known preservatives such as ammonium salt derivatives can be used. Particularly preferred preservatives include pyridinethiol-1-oxide salts, salicylic acid and its salts, 1,3,5-trishydroxyethylhexahydro-S-triazine, 1,3,5-trishydroxymethylhexahydro-S- Examples include triazine, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, and 2-bromo-2-nitro-1,3-propanediol. In addition, it is preferable to use two or more kinds of preservatives together so as to be effective against various molds and bacteria. A preferable content is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, but 0.01 to 4% by mass with respect to the gum solution. The range of is preferable.

  The gum solution can also contain a lipophilic substance. Preferred lipophilic substances include organic carboxylic acids having 5 to 25 carbon atoms such as oleic acid, lanolinic acid, valeric acid, nonylic acid, capric acid, myristic acid, palmitic acid, castor oil and the like. Lipophilic substances can be used alone or in combination of two or more. The lipophilic substance contained in the gum solution is in the range of 0.005 to 10% by mass, more preferably 0.05 to 5% by mass, based on the total mass.

  In addition, glycerin, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin, polyoxyethylene, etc. are used as a wetting agent if necessary in the gum solution Can be added. The wetting agent may be used alone or in combination of two or more. A preferable amount of the wetting agent is 0.1 to 5% by mass.

  A chelate compound may be added to the gum solution. The gum solution is usually marketed as a concentrated solution, and is used by diluting with tap water, well water or the like at the time of use. Calcium ions contained in the diluted tap water and well water may adversely affect printing and may cause the printed matter to become dirty. Therefore, the above disadvantages can be eliminated by adding a chelate compound. . Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, its potassium salt, its sodium salt; diethylenetriaminepentaacetic acid, its potassium salt, its sodium salt; triethylenetetraminehexaacetic acid, its potassium salt, its sodium salt, hydroxyethylethylenediaminetrimethyl Acetic acid, potassium salt, sodium salt; nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium Examples thereof include organic phosphonic acids such as salts and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents. A rate agent is selected that is stably present in the gum solution composition and does not impair the printability. The content is suitably 0.001 to 1.0 mass% with respect to the gum solution.

  The gum solution can also contain an antifoaming agent, and a silicon antifoaming agent is particularly preferred. Among them, an emulsified dispersion type and a solubilized type can be used. The preferred content is in the range of 0.001 to 1.0 mass% with respect to the gum solution.

  The gum solution may be prepared as an emulsified dispersion type, an organic solvent is used as its oil phase, and it may be made into a solubilized type (emulsified type) with the aid of a surfactant as described above. .

The organic solvent is preferably an organic solvent having a solubility in water at 20 ° C. of 5% by mass or less and a boiling point of 160 ° C. or more. For example, phthalic acid diester agents such as dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, etc. Aliphatic dibasic acid esters such as butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di (2-ethylhexyl) sebacate, dioctyl sebacate, for example, epoxidized triglycerides such as epoxidized soybean oil, The freezing point of phosphoric acid esters such as cresyl phosphate, trioctyl phosphate, trischlorl phosphate, and benzoic acid esters such as benzyl benzoate is 15 ° C. or lower. Boiling point at one atmosphere include 300 ° C. or more plasticizers.

  Examples of other alcohols include 2-octanol, 2-ethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, and benzyl alcohol. Examples of glycols include ethylene glycol isoamyl ether, ethylene glycol monophenyl ether, ethylene glycol benzyl ether, ethylene glycol hexyl ether, and octylene glycol.

  Odor is particularly mentioned as a condition when selecting the compound. A preferable range of the amount of these solvents used is 0.1 to 5% by mass of the desensitizing agent, and a more preferable range is 0.5 to 3% by mass. Two or more solvents can be used in combination.

  In addition to the above-mentioned gum solution, gum solutions described in EP 1342568B1 and EP 1788444A1 may be suitably used.

  The gum solution is prepared by preparing a water phase at a temperature of 40 ° C. ± 5 ° C., stirring at high speed, slowly dropping the prepared oil phase into the water phase, stirring sufficiently, and then emulsifying and dispersing through a pressure type homogenizer. The

  The remaining component of the gum solution is water. It is advantageous for transportation that the gum solution is a concentrated solution with a reduced water content and is diluted with water at the time of use. In this case, the degree of concentration is appropriate such that each component does not cause separation or precipitation.

  The temperature of the processing solution in the development step of the present invention, the water in the washing step, and the gum solution in the desensitization step can be used separately at any temperature, but is preferably in the range of 10 to 50 ° C.

  In the present invention, a drying step can be optionally provided after each step. In particular, it is preferably provided in the last step of the automatic processor, and more preferably provided between the water washing step and the desensitization step. This drying step is generally performed by spraying drying air at an arbitrary temperature after removing most of the processing liquid at the roller nip.

Prior to the above development processing, the lithographic printing plate precursor is exposed through a transparent original image having a line image, a halftone dot image or the like, or imagewise exposed by laser beam scanning or the like using digital data. Examples of light sources suitable for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal hydrado lamps, strobes, ultraviolet rays, infrared rays, and laser beams. A laser beam is particularly preferable, and examples thereof include solid-state lasers and semiconductor lasers that emit infrared light of 760 to 1200 nm, ultraviolet semiconductor lasers that emit light of 250 to 420 nm, argon ion lasers that emit visible light, and FD-YAG lasers. Among these, from the viewpoint of simplification of plate making, a laser emitting infrared rays that can be operated under white light or yellow light is preferable.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 μs, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . A multi-beam laser device is preferably used to shorten the exposure time.

The constituent elements and components of the lithographic printing plate precursor used in the present invention are described below.
[Lithographic printing plate precursor]
The lithographic printing plate precursor used in the present invention has an image forming layer containing specific polymer particles on a support, and after exposure, the processing liquid of the present invention is supplied to remove unexposed portions. It can be formed. In the present invention, “having an image forming layer on a support” does not deny the presence of an optional layer such as a protective layer, an undercoat layer, an intermediate layer, and a backcoat layer provided as desired.

(Image forming layer)
<Polymer fine particles>
In the lithographic printing plate precursor according to the present invention, image formation of polymer fine particles (hereinafter also referred to as polymer particles of the present invention) containing a repeating unit having a polyalkylene oxide segment in the side chain and a repeating unit having a cyano group in the side chain It is characterized by including in a layer.

  The polymer particles of the present invention are particles comprising a polymer having a number average molar mass (Mn) of preferably about 10,000 to about 250,000, more preferably 25,000 to 200,000, The diameter is preferably from about 0.01 μm to about 1 μm, more preferably from about 100 nm to about 700 nm, and even more preferably from about 150 nm to about 250 nm.

  The polymer used in the polymer particles of the present invention may be an addition polymer or a condensation polymer. Addition polymers can be prepared from, for example, acrylate and methacrylate esters, acrylic and methacrylic acid, methyl methacrylate, allyl acrylate and allyl methacrylate, acrylamide and methacrylamide, acrylonitrile and methacrylonitrile, styrene, hydroxystyrene, or combinations thereof. it can. Suitable condensation polymers include polyurethanes, epoxy resins, polyesters, polyamides, and phenolic polymers including phenol / formaldehyde and pyrogallol / acetone polymers.

  The polymer includes a hydrophobic backbone that includes structural units having pendant groups attached thereto. The hydrophobic main chain may be all carbon atoms as in the case where the polymer is a copolymer derived from a combination of ethylenically unsaturated monomers, and the hydrophobicity as in the case where the polymer is formed by a condensation reaction or the like. The sex backbone may contain heteroatoms.

  The polymer includes a repeating unit having a cyano group in a side chain. As this monomer unit, (meth) acrylonitrile, methyl cyanoacrylate, ethyl cyanoacrylate, or a combination thereof is preferable. Of these, (meth) acrylonitrile is particularly preferred. The term “(meth) acrylonitrile” as used herein refers to acrylonitrile or methacrylonitrile, or a combination of acrylonitrile and methacrylonitrile.

  The polymer is also characterized by including a repeating unit containing a poly (alkylene oxide) segment in the side chain. The poly (alkylene oxide) segment can be, for example, an oligomer or polymer containing blocks consisting of alkylene oxide building blocks. The side chain with this poly (alkylene oxide) segment is generally predominantly a poly (alkylene oxide) segment, or two or more such segments, but contains a linking group and a terminal group with the main chain. You can also.

The alkylene oxide constituent unit is a (C1-C6) alkylene oxide group, more typically a (C1-C3) alkylene oxide group. For example, the poly (alkylene oxide) segment can comprise linear or branched alkylene oxide groups of 1 to 3 carbon atoms, these groups can be represented by — [CH ₂ O—], — [CH ₂ CH ₂ O-],-[CH (CH ₃ ) O-],-[CH ₂ CH ₂ CH ₂ O-],-[CH (CH ₃ ) CH ₂ O-],-[CH ₂ CH (CH ₃ ) O-], or any of the foregoing. Among _{these, - [CH 2 CH 2 O} -], - [CH 2 CH (CH 3) O-] is more preferably constituent units _{of, - [CH 2 CH 2 O-} ] That oxide is more preferable.

  The poly (alkylene oxide) segment typically comprises a total of about 5 to about 150 alkylene oxide building units. Generally, the number average molar mass (Mn) of the poly (alkylene oxide) segment is from about 300 to about 10,000, more preferably from about 500 to about 5,000, more preferably from about 1,000 to about 3 ,. 000.

One example of a suitable pendant group comprising a poly (alkylene oxide) segment is a pendant group of —C (═O) O — [(CH ₂ ) _x O—] _y R, where x is 1 to 3 , Y is from about 5 to about 150, and R is a suitable end group. Suitable end groups R are, for example, alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, t-butyl, n-pentyl, isopentyl. , Neopentyl, n-hexyl, isohexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, cyclopentyl, and cyclohexyl.

A specific example of a suitable pendant group comprising a poly (alkylene oxide) segment is a pendant group of —C (═O) O— [CH ₂ CH ₂ O—] _y CH ₃ , wherein y is about 10 To about 100, and more preferably y is from about 25 to about 75, and even more preferably, y is from about 40 to about 50.

  The polymer may also include repeat units derived from other suitable polymerizable monomers or oligomers. For example, acrylate esters, methacrylate esters, styrene, hydroxystyrene, acrylic acid, methacrylic acid, methacrylamide, or any combination of the foregoing are preferred. Particularly suitable are repeating units derived from styrene, methacrylamide, methyl methacrylate, allyl methacrylate. More specifically, a repeating unit having an unsubstituted or substituted pendant phenyl group directly bonded to the main chain is useful. Substituted phenyl groups include, for example, 4-methylphenyl, 3-methylphenyl, 4-methoxyphenyl, 4-cyanophenyl, 4-chlorophenyl, 4-fluorophenyl, 4-acetoxyphenyl, and 3,5-dichlorophenyl. Such repeating units can be derived, for example, from styrene or substituted styrene monomers.

  The polymer preferably contains about 70 mol% to about 99.9 mol% of repeating units having a cyano group, and more preferably about 75 mol% to about 95 mol% of the whole repeating units. The repeating unit containing a poly (alkylene oxide) segment in the side chain is preferably contained in an amount of about 0.1 mol% to about 5 mol%, more preferably about 0.5 mol% to about 2 mol%. When other repeating units such as styrene and acrylamide are included, the range is preferably about 0 mol% to about 30 mol%, more preferably about 2 mol% to about 20 mol%, More preferably from 5 mol% to about 15 mol%.

Specific examples of the polymer include: i) a repeating unit having a cyano group in the side chain; ii) a repeating unit having a poly (alkylene oxide) segment in the side chain; and iii) directly bonded to the hydrophobic main chain. A random copolymer comprising a repeating unit having an unsubstituted or substituted phenyl group in the side chain can be exemplified.
More specifically, i) a repeating unit of — [CH ₂ C (R) (C≡N) —]; ii) a repeating unit of — [CH ₂ C (R) (PEO) —] (in the above formula, PEO represents the side chain of —C (═O) O— [CH ₂ CH ₂ O—] _y CH ₃ , y is about 25 to about 75); and iii) — [CH ₂ CH (Ph) — ] (In the above formula, each R independently represents —H or —CH ₃ , and Ph represents a phenyl group).
More specifically, a random copolymer of about 70 to about 99.9 mole% in the total repeating units in the polymer _{- [CH 2 C (R)} (C≡N) -] have; repeat units in the random copolymer about 0.1 to about 5 mole% in total is _{- [CH 2 C (R)} (PEO) -] in there; random copolymers from about 2 to about 20 mole% in total repeating units in the polymer form - [CH It is a random copolymer with ₂ CH (Ph)-].

  The polymer is typically a random copolymer obtained by radical copolymerization of a mixture of two or more monomers. In a typical preparation, two or more monomers, a monomer that is a precursor of a repeating unit having a cyano group in the side chain, and a precursor of a repeating unit that includes a poly (alkylene oxide) segment in the side chain A mixture containing at least another monomer (more suitably called “macromer”) is copolymerized. As used herein, the phrases “mixture of monomers” and “combination of monomers” include mixtures or combinations of one or more polymerizable monomers and / or polymerizable macromers.

In one example, the polymer is a suitable monomer / macromer, such as:
A) Acrylonitrile, methacrylonitrile, or combinations thereof (ie (meth) acrylonitrile);
B) A poly (alkylene glycol) ester of acrylic or methacrylic acid, such as poly (ethylene glycol) methyl ether acrylate, poly (ethylene glycol) methyl ether methacrylate, or combinations thereof (ie, poly (ethylene glycol) methyl ether (meta ) Acrylate); and C) can optionally be formed by polymerization of monomers such as styrene, acrylamide, methacrylamide and the like, or combinations or mixtures of suitable monomers.

Precursors useful as monomers or macromers B) are, for example, polyethylene glycol monomethacrylate, polyethylene glycol monoacrylate, polyethylene glycol methyl ether methacrylate, polyethylene glycol ethyl ether methacrylate, polyethylene glycol butyl ether methacrylate, polyethylene glycol methyl ether acrylate, polyethylene glycol ethyl ether. Acrylate, polyethylene glycol phenyl ether acrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, polypropylene glycol methyl ether methacrylate, polypropylene glycol ethyl ether methacrylate, polypropylene glycol buty Ether methacrylate, polypropylene glycol hexyl ether methacrylate, polypropylene glycol octyl ether methacrylate, (polyethylene glycol / polypropylene glycol) methyl ether methacrylate, or mixtures thereof.
The term “(meth) acrylate” as used herein in connection with polymerizable macromers includes acrylate or methacrylate macromers, or a combination of acrylate and methacrylate macromers. The phrase “alkyl ether” with respect to macromers refers to lower alkyl ethers, generally (C1-C6) linear or branched saturated alkyl ethers such as methyl ether or ethyl ether.

  Suitable monomers that can be used as optional monomer C) are, for example, acrylic acid, methacrylic acid, acrylate esters, methacrylate esters, such as methyl methacrylate, allyl methacrylate, hydroxyethyl methacrylate, styrene, hydroxystyrene, methacrylamide, or Including any combination of the foregoing. Particularly suitable are styrene or methacrylamide or monomers derived therefrom. Specific examples of suitable monomers are styrene, 3-methylstyrene, 4-methylstyrene, 4-methoxystyrene, 4-acetoxystyrene, α-methylstyrene, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, n-hexyl. Acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, n-pentyl methacrylate, neo-pentyl methacrylate, cyclohexyl methacrylate, n-hexyl methacrylate, 2-ethoxyethyl methacrylate, 3-methoxypropyl methacrylate , Allyl methacrylate, vinyl acetate, vinyl butyrate, methyl vinyl ketone, butyl vinyl ketone, vinyl fluoride, vinyl chloride, vinyl bromide, maleic anhydride, maleimi , Including N- phenylmaleimide, N- cyclohexyl maleimide, N- benzyl maleimide, and mixtures thereof.

  For example, the polymer can be prepared by radical polymerization. Radical polymerization is well known to those skilled in the art and is described, for example, in Macromolecules Vol. 2, 2nd edition, edited by H.G. Elias, Chapters 20 and 21 of Plenum, New York, 1984. Useful free radical initiators are peroxides such as benzoyl peroxide, hydroperoxides such as cumyl hydroperoxide, and azo compounds such as 2,2′-azobis-isobutyronitrile (V-601). Chain transfer agents such as dodecyl mercaptan can be used to control the molecular weight of the compound.

Specific examples of the polymer include about 55 to about 90 weight percent (meth) acrylonitrile; about 5 to about 15 weight percent poly (ethylene glycol) alkyl ether (meth) acrylate; and about 5 to about 30 weight percent Of styrene.
More specifically, from a combination of monomers consisting of about 55 to about 90 weight percent acrylonitrile; about 5 to about 15 weight percent poly (ethylene glycol) methyl ether methacrylate; and about 5 to about 30 weight percent styrene. A derivatized copolymer.

  In general, a solvent suitable for radical polymerization is selected which is inert to the reactants and does not have a particularly adverse effect on the reaction. For example, esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and acetone; alcohols such as methanol, ethanol, isopropyl alcohol, and butanol; ethers such as dioxane and tetrahydrofuran; And mixtures thereof.

  The polymer particles are preferably prepared in a hydrophilic medium (water or a mixture of water and alcohol). A hydrophilic medium can facilitate the formation of particles dispersed in a solvent. Furthermore, it may be desirable to carry out the polymerization in a solvent system that does not completely dissolve the monomers that are precursors of repeating units that provide hydrophobic character to the polymer backbone, such as acrylonitrile or methacrylonitrile. For example, it can be synthesized in a water / alcohol mixture, such as a mixture of water and n-propanol.

All monomers / macromers and polymerization initiator can be added directly to the reaction medium, and the polymerization reaction proceeds at an appropriate temperature determined by the selected polymerization initiator. Alternatively, a macromer containing a poly (alkylene oxide) segment can be added first to the reaction solvent and the monomer can be added slowly after the temperature rise. The initiator can be added to the monomer mixture, to the macromer solution, or both.

  While the preparation of the polymer has been described with respect to monomers and macromers that can be used to form copolymers, the invention is limited to the use of copolymers formed by the polymerization of a mixture of two or more monomers. is not. The polymer can be formed by other routes apparent to those skilled in the art, for example by modification of the precursor polymer. For example, the polymer can be prepared as a graft copolymer, such as when a poly (alkylene oxide) segment is grafted onto a suitable polymeric precursor. Such grafting can be performed, for example, by anionic, cationic, nonionic, or free radical grafting methods.

  In one example, by copolymerizing a suitable combination of polymerizable monomers to produce a graftable copolymer and then grafting a functional group comprising a poly (alkylene oxide) segment onto the graftable copolymer. The polymer can be prepared. For example, graft copolymers can be prepared by reacting a hydroxy-functional or amine-functional polyethylene glycol monoalkyl ether with a polymer having co-reactive groups including acid chloride, isocyanate, and anhydride groups. Other methods for preparing graft copolymers suitable for use include those described in US Pat. No. 6,582,882.

<Other binder polymers>
In addition to the polymer particles of the present invention, the imaging layer may optionally include one or more other binder polymers. Typical examples are water-soluble or water-dispersible polymers such as cellulose derivatives: eg carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose; polyvinyl alcohol; polyacrylic acid; polymethacrylic acid; polyvinylpyrrolidone; Polylactide, polyvinylphosphonic acid; synthetic copolymers such as copolymers of alkoxy polyethylene glycol acrylate or methacrylate, such as methoxy polyethylene glycol acrylate or methacrylate, and monomers such as methyl methacrylate, methyl acrylate, butyl methacrylate, butyl acrylate, or allyl methacrylate; and these It is a mixture of

The other binder polymer preferably contains a crosslinkable site. The crosslinkable site is preferably an ethylenically unsaturated group. For example, by containing allyl methacrylate as a copolymerization component, a polymer containing an ethylenically unsaturated group can be obtained. Another method of introducing an ethylenically unsaturated group into the binder polymer is to prepare a copolymer containing methacrylic acid as a copolymerization component and then introduce an epoxy group-containing compound such as glycidyl methacrylate by a polymer reaction. More preferred. A polymer obtained by partially modifying polyvinyl alcohol as described in EP 1788431A2 with methacrylic anhydride or isocyanate group-containing ethyl methacrylate is also preferably used.
The content of the other binder polymer is preferably 0% by mass to about 50% by mass, and more preferably about 1% by mass to about 30% by mass in the total solid content of the image forming layer.

  The total amount of the above-described polymer particles of the present invention and the other binder polymer is preferably about 10% by weight to about 80% by weight, more preferably about 20% by weight to about 50% by weight in the total solid content of the image forming layer. %, Most preferably from about 30% to about 40% by weight. By containing the polymer particles of the present invention and other binder polymer in this amount in the image forming layer, the image forming layer can be made soluble or dispersible in the processing liquid according to the present invention.

A typical image forming mechanism of the image forming layer according to the present invention includes (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound. The aspect which forms is mentioned.
Hereinafter, each component contained in the image forming layer according to the present invention (hereinafter also referred to as a photosensitive layer) will be sequentially described.

(A) Sensitizing dye For example, a sensitizing dye having a maximum absorption at 350 to 450 nm, a sensitizing dye having a maximum absorption at 500 to 600 nm, and an infrared absorber having a maximum absorption at 750 to 1400 nm are added to the photosensitive layer. By doing so, it is possible to provide a high-sensitivity lithographic printing plate precursor corresponding to a 405 nm violet laser, a 532 nm green laser, and a 803 nm IR laser, which are usually used in the industry.
First, a sensitizing dye having a maximum absorption in the wavelength region of 350 to 450 nm will be described. Examples of such a sensitizing dye include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, anthracenes, and the like.

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

In general formula (IV), A represents an aromatic ring group or a heterocyclic group which may have a substituent, and X represents an oxygen atom, a sulfur atom or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represent a monovalent nonmetallic atomic group, and A and R ₁ and R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be formed.

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

A in the general formula (IV) represents an aromatic ring group or a heterocyclic group which may have a substituent, and the aromatic ring or heterocyclic ring which may have a substituent in the general formula (IV) And the same as the substituted or unsubstituted aryl group and the substituted or unsubstituted aromatic heterocyclic residue described in R ₁ , R ₂ and R ₃ in FIG.

  Specific examples of such sensitizing dyes include compounds described in JP-A-2007-58170, [0047 to [0053].

  Furthermore, sensitizing dyes represented by the following general formulas (V) to (VII) can also be used.

In formula (V), R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In the formula (VI), R ^{15 to} R ³² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

In formula (VII), R ¹ , R ² and R ³ each independently represents a halogen atom, an alkyl group, an aryl group, an aralkyl group, an —NR ⁴ R ⁵ group or an —OR ⁶ group, and R ⁴ , R ⁵ And R ⁶ each independently represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and k, m and n each represents an integer of 0 to 5.

JP-A-2007-171406, JP-A-2007-206216, JP-A-2007-206217, JP-A-2007-225701, JP-A-2007-225702, JP-A-2007-316582, JP-A-2007-328243 The sensitizing dyes described in 1) can also be preferably used.
A preferable addition amount of a sensitizing dye having an absorption maximum in a wavelength region of 350 nm to 450 nm is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts per 100 parts by mass of the total solid content of the photosensitive layer. It is in the range of part by weight, most preferably 0.2 to 10 parts by weight.

Subsequently, a sensitizing dye having a maximum absorption in a wavelength range of 750 to 1400 nm that is preferably used in the present invention will be described in detail.
Such a sensitizing dye includes an infrared absorber and is highly sensitive to infrared laser irradiation (exposure) in an electronically excited state. Electron transfer, energy transfer, and heat generation (photothermal conversion function) associated with the electronically excited state. It is estimated that these act on the polymerization initiator coexisting in the photosensitive layer to cause a chemical change in the polymerization initiator to generate radicals. In any case, the addition of a sensitizing dye having a maximum absorption at 750 to 1400 nm is particularly suitable for plate making directly drawn with an infrared laser beam having a wavelength of 750 to 1400 nm, and the conventional lithographic printing plate precursor Compared with this, high image forming properties can be exhibited.

  The infrared absorber is preferably a dye or pigment having an absorption maximum in a wavelength region of 750 nm to 1400 nm.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as 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, etc. Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In the general 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, a nitrogen 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 1 to 1 carbon atom containing a hetero atom. 12 hydrocarbon groups are shown. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se. X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl 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, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and charge neutralization is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a hexagonal salt, in view of the storage stability of the photosensitive layer coating solution. Fluorophosphate ions and aryl sulfonate ions. In addition, the thing which does not contain a halogen ion as a counter ion is especially preferable.

In the present invention, it is preferable to use a water-soluble cyanine dye as the sensitizing dye.
Examples of the water-soluble cyanine dye include those described in JP-A-2004-351823, and a hydrophilic group in the molecule includes a sulfonic acid group and / or a salt thereof, a phosphonic acid group and / or a salt thereof, It preferably has at least one selected from a carboxylic acid group and / or a salt thereof, and a hydroxyl group.
Of these, it is more preferable that the molecule has two or more sulfonic acid groups and / or salts thereof, phosphonic acid groups and / or salts thereof, and the counter ion is an inorganic ion.

  Although the specific example of the water-soluble cyanine dye suitable for this invention is shown below, it is not limited to these.

  Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology", published by CMC Publishing, 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 other polymer-bonded dyes. 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, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. 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. Within this preferred particle size range, excellent dispersion stability of the pigment in the photosensitive layer can be obtained, and a uniform photosensitive layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  The infrared absorber may be added to the same layer as other components, or another layer may be provided and added thereto.

  From the viewpoint of uniformity in the photosensitive layer and durability of the photosensitive layer, the infrared absorbent is 0.01 to 50% by mass, preferably 0.1 to 10% by mass, based on the total solid content constituting the photosensitive layer. In the case of, it is particularly preferably 0.5 to 10% by mass, and in the case of a pigment, particularly preferably 0.1 to 10% by mass.

(B) Polymerization initiator
The photosensitive layer of the present invention contains a polymerization initiator (hereinafter also referred to as an initiator compound). The initiator compound is a compound that undergoes a chemical change through the action of electron transfer, energy transfer, heat generation, etc. caused by the electronic excitation state of the sensitizing dye, and generates at least one selected from radicals, acids, and bases. is there. Hereinafter, radicals, acids, and bases generated in this way are simply referred to as active species. When the initiator compound is not present or when only the initiator compound is used alone, practically sufficient sensitivity cannot be obtained. As one mode in which a sensitizing dye and an initiator compound are used in combination, they can be used as a single compound by an appropriate chemical method (such as linking a sensitizing dye and an initiator compound through a chemical bond). It is.

  Usually, many of these initiator compounds are considered to generate active species through the initial chemical processes represented by the following (1) to (3). (1) Reductive decomposition of the initiator compound based on the electron transfer reaction from the electronically excited state of the sensitizing dye to the initiator compound, (2) Electron transfer from the initiator compound to the electronically excited state of the sensitizing dye (3) decomposition of the initiator compound from the electronically excited state based on energy transfer from the electronically excited state of the sensitizing dye to the initiator compound. In many cases, it is ambiguous as to which type (1) to (3) each individual initiator compound belongs, but in the present invention, a very high increase can be achieved by combining any of these types of initiator compounds. A feeling effect is obtained.

  As the initiator compound in the present invention, those known among those skilled in the art can be used without limitation. Specifically, for example, trihalomethyl compounds, carbonyl compounds, organic peroxides, azo compounds, azide compounds, metallocene compounds can be used. , Hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, oxime ester compounds, onium salt compounds, and iron arene complexes. Among these, at least one selected from the group consisting of hexaarylbiimidazole compounds, onium salts, trihalomethyl compounds, and metallocene compounds is preferable, and hexaarylbiimidazole compounds are particularly preferable. Two or more polymerization initiators may be used in combination as appropriate.

Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B Nos. 45-37377 and 44-86516, such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5. '-Tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) -4 , 4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) biimidazole, 2,2 ' -Bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5,5'-tetraf Nilbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.
The hexaarylbiimidazole compound is particularly preferably used in combination with a sensitizing dye having a maximum absorption at 350 to 450 nm.

  The onium salt suitably used in the present invention (in the present invention, functions as an ionic polymerization initiator, not as an acid generator) is represented by the following general formulas (RI-I) to (RI-III). Onium salt.

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include an alkyl group having 1 to 12 carbon atoms and a carbon number. C2-C12 alkenyl group, C2-C12 alkynyl group, C6-C12 aryl group, C1-C12 alkoxy group, C6-C12 aryloxy group, halogen atom, C1-C1 12 alkylamino groups, C2-C12 dialkylamino groups, C1-C12 alkylamide groups or arylamide groups, carbonyl groups, carboxyl groups, cyano groups, sulfonyl groups, C1-C12 thioalkyl groups And a thioaryl group having 6 to 12 carbon atoms. Z ₁₁ ^- represents a monovalent anion, specifically a halogen ion, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, thiosulfonate ion, a sulfate ion Can be mentioned. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion and sulfinate ion are preferable from the viewpoint of stability.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 1 carbon atoms. 12 alkyl groups, alkenyl groups having 2 to 12 carbon atoms, alkynyl groups having 2 to 12 carbon atoms, aryl groups having 6 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, aryloxy groups having 6 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C2-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 6 to 12 carbon atoms. Z ₂₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, sulfate ions, and carboxylate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoint of stability and reactivity.

In the formula (RI-III), R ₃₁ , R ₃₂ and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents a group. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Examples of the substituent include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, Aryloxy group having 6 to 12 carbon atoms, halogen atom, alkylamino group having 1 to 12 carbon atoms, dialkylamino group having 2 to 12 carbon atoms, alkylamide group or arylamide group having 1 to 12 carbon atoms, carbonyl group, carboxyl Group, a cyano group, a sulfonyl group, a thioalkyl group having 1 to 12 carbon atoms, and a thioaryl group having 6 to 12 carbon atoms. Z ₃₁ ^- represents a monovalent anion. Specific examples include halogen ions, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, thiosulfonate ions, sulfate ions, and carboxylate ions. Among these, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.
The onium salt is particularly preferably used in combination with an infrared absorber having a maximum absorption at 750 to 1400 nm.

  In addition, JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, JP 2007-316582, JP 2007-328243. Can be preferably used.

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

<(C) Polymerizable compound>
The polymerizable compound (C) that can be used in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably two or more. It is chosen from the compound which has. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or copolymers thereof, and mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyamine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or Also suitable are substitution reaction products of unsaturated carboxylic acid esters or amides having a leaving substituent such as a tosyloxy group with monofunctional or polyfunctional alcohols, amines or thiols. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomer.

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

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

Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59-5241, Those having an aromatic skeleton described in Kaihei 2-226149, those containing an amino group described in JP-A-1-165613, and the like are also preferably used.
The aforementioned ester monomers can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B-54-21726.

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

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

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, and JP-B-2-16765, JP-B-58-49860, JP-B-56-17654, Urethane compounds having an ethylene oxide skeleton described in JP-B-62-39417 and JP-B-62-39418 are also suitable. Further, by using addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238, It is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

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

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

In the present invention, the polymerizable compound (C) is preferably used in the range of 5 to 80% by mass, and more preferably 25 to 75% by mass with respect to the nonvolatile component in the image forming layer.
In addition, the use method of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. Depending on the case, a layer configuration / coating method such as undercoating or overcoating can be carried out.

<Other ingredients>
(1) Surfactant In the image forming layer of the present invention, a surfactant can be used to promote developability and improve the coated surface.
Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants.

  The nonionic surfactant used for this invention is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  The anionic surfactant used in the present invention is not particularly limited, and conventionally known anionic surfactants can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

The cationic surfactant used in the present invention is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.
The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known amphoteric surfactants can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. These surfactants can also be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Moreover, the fluorine-type surfactant described in Unexamined-Japanese-Patent No. 62-170950, 62-226143, and 60-168144 is also mentioned suitably.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the image forming layer.

(2) Colorant In the image forming layer in the invention, a dye having a large absorption in the visible light region can be used as an image colorant. 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 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI 42555), Methyl Violet (CI 42535), Ethyl Violet, Rhodamine B (CI 45170B), Malachite Green (CI 42000), Methylene Blue (CI 522015), etc. And dyes described in No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.
When a colorant is used, it is easy to distinguish between an image portion after image formation and a non-image portion.
A suitable addition amount of the colorant is 0.01 to 10% by mass with respect to the total solid content of the image forming layer.

(3) Print-out agent To the image forming layer in the invention, a compound that changes color by an acid or a radical can be added in order to produce a print-out image.
As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Red, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachite Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Industry Co., Ltd.], Oil Pink # 312 [Made by Orient Chemical Co., Ltd.], Oil Red 5B [Made by Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orientation] Industrial Co., Ltd.], Oil Red OG [Orient Chemical Industry Co., Ltd.], Oil Red RR [Orient Chemical Industry Co., Ltd.], Oil Green # 502 [Orient Chemical Industry Co., Ltd.], Spiron Red BEH Special [Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p-diethylamino Phenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1 -Β-naphthyl-4-p Dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

  A suitable addition amount of the dye that changes color by an acid or a radical is preferably 0.01 to 10% by mass with respect to the solid content of the image forming layer.

(4) Polymerization inhibitor In the image forming layer of the present invention, a small amount of a thermal polymerization inhibitor is added to the image forming layer in order to prevent unnecessary thermal polymerization of the polymerizable compound during the production or storage of the image forming layer. It is preferable to add.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-thiobis (3-methyl-6-t- (Butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), and N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the image forming layer.

(5) Higher fatty acid derivatives and the like In the image forming layer in the present invention, a higher fatty acid derivative such as behenic acid and behenic acid amide is added to prevent polymerization inhibition due to oxygen, and the drying process after coating is performed. May be unevenly distributed on the surface of the image forming layer.
The amount of the higher fatty acid derivative added is preferably about 0.1 to about 10% by mass with respect to the total solid content of the image forming layer.

(6) Plasticizer The image forming layer in the invention may contain a plasticizer in order to improve developability.
Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in.
The plasticizer content is preferably about 30% by mass or less based on the total solid content of the image forming layer.

(7) Inorganic fine particles The image forming layer in the present invention may contain inorganic fine particles in order to improve the strength of the cured film and the developability.
Suitable inorganic fine particles include, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof. These can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like.
The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 μm to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the image forming layer, sufficiently retains the film strength of the image forming layer, and hardly causes stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 40% by mass or less, and more preferably 30% by mass or less, based on the total solid content of the image forming layer.

(8) Low molecular weight hydrophilic compound The image forming layer in the invention may contain a low molecular weight hydrophilic compound because it improves developability without reducing printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid and salts thereof, alkylsulfamic acid and the like Organic sulfamic acids and their salts, organic sulfuric acids and their salts such as alkyl sulfuric acid and alkyl ether sulfuric acid, organic phosphonic acids and their salts such as phenylphosphonic acid, tartaric acid, sulphate , Citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids and the like.
Among these, organic sulfonic acids, organic sulfamic acids, and organic sulfates such as sodium and lithium salts of organic sulfuric acid are preferably used.

  Specific examples of organic sulfonates include sodium normal butyl sulfonate, sodium isobutyl sulfonate, sodium sec-butyl sulfonate, sodium tert-butyl sulfonate, sodium normal pentyl sulfonate, and sodium 1-ethylpropyl sulfonate. Sodium hexyl sulfonate, sodium 1,2-dimethylpropyl sulfonate, sodium 2-ethylbutyl sulfonate, sodium cyclohexyl sulfonate, sodium normal heptyl sulfonate, sodium normal octyl sulfonate, sodium tert-octyl sulfonate, normal Sodium nonyl sulfonate, sodium allyl sulfonate, sodium 2-methylallyl sulfonate, sodium benzene sulfonate Sodium p-toluenesulfonate, sodium p-hydroxybenzenesulfonate, sodium p-styrenesulfonate, dimethyl-5-sulfonate sodium isophthalate, disodium 1,3-benzenedisulfonate, 1,3,5-benzenetri Trisodium sulfonate, sodium p-chlorobenzenesulfonate, sodium 3,4-dichlorobenzenesulfonate, sodium 1-naphthylsulfonate, sodium 2-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, 1,5-naphthyldisulfone Examples thereof include disodium acid, disodium 2,6-naphthyldisulfonate, trisodium 1,3,6-naphthyltrisulfonate, and lithium salt exchangers thereof.

  Specific examples of the organic sulfamate include sodium normal butyl sulfamate, sodium isobutyl sulfamate, sodium tert-butyl sulfamate, sodium normal pentyl sulfamate, sodium 1-ethylpropyl sulfamate, sodium normal hexyl sulfamate, Examples include sodium 1,2-dimethylpropylsulfamate, sodium 2-ethylbutylsulfamate, sodium cyclohexylsulfamate, and lithium salt exchangers thereof.

  These compounds have a small hydrophobic part structure and almost no surface-active action, and are clearly distinguished from the above-mentioned surfactants in which long-chain alkyl sulfonates and long-chain alkyl benzene sulfonates are used favorably. .

  As the organic sulfate, a compound represented by the following general formula (iii) is particularly preferably used.

In the general formula (iii), R represents an alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group, m represents an integer of 1 to 4, and X represents sodium, potassium or lithium.

  R is preferably a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, or an aryl group having 20 or less carbon atoms. Can be mentioned. These groups may further have a substituent. In that case, examples of the substituent that can be introduced include linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, and those having 2 to 12 carbon atoms. Examples include an alkenyl group, an alkynyl group having 2 to 12 carbon atoms, a halogen atom, and an aryl group having 20 or less carbon atoms.

  Preferred examples of the compound represented by the general formula (iii) include sodium oxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, dioxyethylene Ethylene-2-ethylhexyl ether lithium sulfate, sodium trioxyethylene-2-ethylhexyl ether sulfate, sodium tetraoxyethylene-2-ethylhexyl ether sulfate, sodium dioxyethylene hexyl ether sulfate, sodium dioxyethylene octyl ether sulfate, dioxyethylene Examples include sodium lauryl ether sulfate. Of these, the most preferred compounds include sodium dioxyethylene-2-ethylhexyl ether sulfate, potassium dioxyethylene-2-ethylhexyl ether sulfate, and lithium dioxyethylene-2-ethylhexyl ether sulfate.

The addition amount of the low molecular weight hydrophilic compound to the image forming layer is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and further preferably 2 to 8% by total solid content of the image forming layer. % By mass. Within this range, good developability and printing durability can be obtained.
A low molecular weight hydrophilic compound may be used independently and may be used in mixture of 2 or more types.

(9) Grease-sensitizing agent In the lithographic printing plate precursor according to the invention, a phosphonium compound can be added as a oil-sensitizing agent to the image forming layer and / or the protective layer in order to improve the inking property. As a suitable phosphonium compound, a compound represented by the following general formula (iv) described in JP-A-2006-297907 or a general formula (v) described in JP-A-2007-50660 can be given.

In the general formula (iv), R _{1 to} R ₄ each independently have an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aryloxy group, which may have a substituent, Represents an alkylthio group, a heterocyclic group or a hydrogen atom; At least two of R _{1 to} R ₄ may be bonded to form a ring. X ⁻ represents a counter anion.

In the general formula (v), Ar _{1 to} Ar ₆ each independently represents an aryl group or a heterocyclic group, L represents a divalent linking group, X ⁿ⁻ represents an n-valent counter anion, n Represents an integer of 1 to 3, and m represents a number satisfying nxm = 2. Here, as the aryl group, phenyl group, naphthyl group, tolyl group, xylyl group, fluorophenyl group, chlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, dimethoxyphenyl group, methoxycarbonylphenyl group, dimethylaminophenyl A group and the like are preferable. Examples of the heterocyclic group include a pyridyl group, a quinolyl group, a pyrimidinyl group, a thienyl group, and a furyl group. L represents a divalent linking group. 6-15 are preferable and, as for carbon number in a connection group, More preferably, it is C6-C12. Preferred examples of X ⁿ⁻ include halide anions such as Cl ⁻ , Br ⁻ and I ⁻ , toluenesulfonate, naphthalene-1,7-disulfonate, naphthalene-1,3,6-trisulfonate, and 5-benzoyl. Examples include sulfonate anions such as -4-hydroxy-2-methoxybenzene-4-sulfonate, carboxylate anions, sulfate ester anions, PF ₆ ⁻ , BF ₄ ⁻ , and perchlorate anions. Of these, a sulfonate anion is particularly preferable.

  Specific examples of the phosphonium compound represented by the general formula (iv) or (v) are shown below.

  In addition to the phosphonium compound, a nitrogen-containing compound is also preferable as the sensitizer. Preferable nitrogen-containing compounds include compounds having the structure of the following general formula (I).

In the formula, R _{1 to} R ₄ each independently represents a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aralkyl group, heterocyclic group or hydrogen atom. At least two of R _{1 to} R ₄ may be bonded to form a ring. X ⁻ is an anion, and PF ₆ ⁻ , BF ₄ ⁻ , or an organic sulfone having a substituent selected from an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, and a heterocyclic group Indicates an acid anion.
That nitrogen-containing compound of the present invention, at least one amine salt is a hydrogen atom R ₁ to R _4, may be a quaternary ammonium salt R ₁ to R ₄ is not any hydrogen atom and the following general formula (II ) Imidazolinium salts represented by the following general formula (III), benzimidazolinium salts represented by the following general formula (III), pyridinium salts represented by the following general formula (IV), and quinolinium salts represented by the following general formula (V) Good.

In the above formula, R ₅ and R ₆ represent a substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, cycloalkyl group, alkoxy group, aryl group, aralkyl group, heterocyclic group or hydrogen atom. X ⁻ is an anion as described above, and includes PF ₆ ⁻ , BF ₄ ⁻ , or a substituent selected from an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aralkyl group, and a heterocyclic group. It has an organic sulfonate anion.

  Among these, quaternary ammonium salts and pyridinium salts are preferably used.

  Specific examples of quaternary ammonium salts are shown below.

  Specific examples of pyridinium salts are shown below.

  The addition amount of the sensitizing agent to the image forming layer or the protective layer is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass in the solid content of each layer. % Is most preferred. Within these ranges, good ink fillability can be obtained.

(10) Co-sensitizer In the image recording layer of the present invention, a known compound called a chain transfer agent or a co-sensitizer having an action of further improving sensitivity or suppressing polymerization inhibition by oxygen is used. May be added.

  Examples of such compounds include amines such as MR Sander et al., “Journal of Polymer Society”, Vol. 10, page 3173 (1972), Japanese Examined Patent Publication No. 44-20189, Japanese Unexamined Patent Publication No. 51-82102, Japanese Unexamined Patent Publication No. 52-134692, JP-A-59-138205, JP-A-60-84305, JP-A-62-18537, JP-A-64-33104, Research Disclosure 33825, and the like. In particular, N, N-dialkylaniline derivatives such as triethanolamine, N-phenylglycine, N-phenylaspartic acid, and p-dimethylaminobenzoic acid ethyl ester, p-formyldimethylaniline, p-methylthiodimethylaniline, etc. Is mentioned.

  Another example of acting as a chain transfer agent is a group of compounds having SH, PH, SiH, GeH in the molecule. These can donate hydrogen to low-activity radical species to generate radicals, or can be oxidized and then deprotonated to generate radicals.

  In the image recording layer of the present invention, in particular, thiol compounds (for example, 2-mercaptobenzimidazoles, 2-mercaptobenzthiazoles, 2-mercaptobenzoxazoles, 3-mercaptotriazoles, 5-mercaptotetrazoles, etc.) Can be preferably used as a chain transfer agent.

  Of these, thiol compounds represented by the following general formula (VI) described in JP-A No. 2006-091479 are particularly preferably used. By using this thiol compound as a chain transfer agent, it avoids odor problems and sensitivity reduction due to evaporation from the image recording layer and diffusion to other layers, and it has excellent storage stability and high sensitivity and high printing durability. A lithographic printing plate precursor is obtained.

  In general formula (VI), R represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and A has a carbon atom together with an N = CN moiety. It represents an atomic group that forms a membered ring or a six-membered heterocyclic ring, and A may further have a substituent.

  More preferably, those represented by the following general formula (VIA) or general formula (VIB) are used.

  In general formulas (VIA) and (VIB), R represents a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent, and X represents a hydrogen atom, a halogen atom, It represents an alkoxyl group that may have a substituent, an alkyl group that may have a substituent, or an aryl group that may have a substituent.

  Specific examples include 1-methyl-2-mercaptobenzimidazole, 1-propyl-2-mercaptobenzimidazole, 1-hexyl-2-mercaptobenzimidazole, 1-hexyl-2-mercapto-5-chlorobenzimidazole. 1-pentyl-2-mercaptobenzimidazole, 1-octyl-2-mercaptobenzimidazole, 1-octyl-2-mercapto-5-methoxybenzimidazole, 1-cyclohexyl-2-mercaptobenzimidazole, 1-phenyl-2 -Mercaptobenzimidazole, 1-phenyl-2-mercapto-5-methylsulfonylbenzimidazole, 1- (p-tolyl) -2-mercaptobenzimidazole, 1-methoxyethyl-2-mercaptobenzimidazole, 1- Til-2-mercaptonaphthimidazole, 1-methyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-butyl-2-mercapto-5-phenyl-1,3,5-triazole, 1- Heptyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-phenyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-benzyl-2-mercapto-5-phenyl- 1,3,5-triazole, 1-phenethyl-2-mercapto-5-phenyl-1,3,5-triazole, 1-cyclohexyl-2-mercapto-5-phenyl-1,3,5-triazole, 1 -Phenethyl-2-mercapto-5- (3-fluorophenyl) -1,3,5-triazole, 1-phenethyl-2-mercapto-5- (3 Trifluoromethylphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (p-tolyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (4 -Methoxyphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5- (p-trifluoromethylphenyl) -1,3,5-triazole, 1-benzyl-2-mercapto-5 (3,5-dichlorophenyl) -1,3,5-triazole, 1-phenyl-2-mercapto-5- (p-tolyl) -1,3,5-triazole, 1-phenyl-2-mercapto-5 (4-methoxyphenyl) -1,3,5-triazole, 1- (1-naphthyl) -2-mercapto-5-phenyl-1,3,5-triazole, 1- (4-bromopheny ) -2-mercapto-5-phenyl-1,3,5-triazole, 1- (4-trifluorophenyl) -2-mercapto-5-phenyl-1,3,5-triazole, 6-bromo-2 -Mercapto-benzimidazole, etc.

  The amount of the sensitizer or chain transfer agent used is preferably 0.01 to 20% by mass, more preferably 0.1 to 15% by mass, based on the total solid content of the image forming layer. More preferably, it is 1.0-10 mass%.

<Formation of image forming layer>
The image forming layer in the invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent, and applying and drying the coating solution.
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-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. A solvent is used individually or in mixture. The solid content concentration of the coating solution is preferably 1 to 50% by mass.

  The image forming layer in the present invention forms a multi-layered image forming layer by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents and repeating a plurality of coatings and dryings. It is also possible.

Although the coating amount (solid content) of the image forming layer on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film properties of the image forming layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

(Protective layer)
The lithographic printing plate precursor according to the invention preferably includes a protective layer (overcoat layer) on the image forming layer.
In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has functions such as preventing scratches in the image forming layer and preventing ablation during high-illuminance laser exposure.
Hereinafter, components constituting the protective layer will be described.

  Usually, the exposure processing of a lithographic printing plate is carried out in the atmosphere. The image forming reaction in the image forming layer caused by the exposure process can be inhibited by low molecular compounds such as oxygen and basic substances present in the atmosphere. The protective layer prevents low molecular compounds such as oxygen and basic substances from entering the image forming layer, and as a result, suppresses the image formation inhibiting reaction in the atmosphere. Therefore, the property desired for the protective layer is to reduce the permeability of low-molecular compounds such as oxygen, and furthermore, the transparency of light used for exposure is good, and the adhesiveness with the image forming layer is excellent. In addition, it can be easily removed in the development process after exposure. The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Examined Patent Publication No. 55-49729.

As a material used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used. Specifically, for example, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, polyacrylic acid, polyacrylamide, partially saponified product of polyvinyl acetate, ethylene-vinyl alcohol copolymer, water-soluble cellulose derivative, gelatin, Examples thereof include water-soluble polymers such as starch derivatives and gum arabic, and polymers such as polyvinylidene chloride, poly (meth) acrylonitrile, polysulfone, polyvinyl chloride, polyethylene, polycarbonate, polystyrene, polyamide, and cellophane.
These may be used in combination of two or more as required.

  A relatively useful material among the above materials includes water-soluble polymer compounds having excellent crystallinity. Specifically, water-soluble acrylic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl imidazole, and polyacrylic acid, gelatin, gum arabic, and the like are suitable. Among these, water can be applied as a solvent, and at the time of printing Polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl imidazole are preferable from the viewpoint that they are easily removed by the fountain solution. Among them, polyvinyl alcohol (PVA) gives the best results for basic properties such as oxygen barrier properties and development removability.

The polyvinyl alcohol that can be used in the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains a substantial amount of an unsubstituted vinyl alcohol unit having the required water solubility. Similarly, a part may contain other copolymerization components. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Polyvinyl alcohol having various degrees of polymerization having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, etc. at the polymer chain end is also preferably used.
Among these, anion-modified polyvinyl alcohol is most preferable because of good dispersion stability in the developer of the present invention. This anion-modified polyvinyl alcohol is preferably contained in an amount of 10 to 50% by mass, more preferably 20 to 40% by mass, based on the total solid content of the protective layer.

Preferred examples of these polyvinyl alcohols include compounds having a hydrolysis of 71 to 100 mol% and a polymerization degree of 300 to 2400. Specifically, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, manufactured by Kuraray Co., Ltd. PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8, and the like.
Moreover, as modified polyvinyl alcohol, KL-318, KL-118, KM-618, KM-118, SK-5102, CKS-50 having an anion-modified site, C-318 having a cation-modified site, C- 118, CM-318, M-205, M-115 having terminal thiol modification sites, MP-103, MP-203, MP-102, MP-202 having terminal sulfide modification sites, ester modification with higher fatty acids Examples thereof include HL-12E and HL-1203 having a site at the end, and R-1130, R-2105, R-2130 having a reactive silane-modified site.

The protective layer preferably contains an inorganic layered compound, that is, a compound that is an inorganic compound, has a layered structure, and has a flat plate shape. By using such an inorganic layered compound in combination, the oxygen barrier property is further increased, and the film strength of the protective layer is further improved and scratch resistance is improved, and the matte property can be imparted to the protective layer. it can.
Examples of the inorganic layered compound include, for example, the formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [where A is Li, K, Na, Ca, Mg, organic cation] Any one of B and C is any one of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, and zirconium phosphate represented by the formula: 3MgO · 4SiO · H ₂ O.

Among the mica compounds, natural mica includes muscovite, soda mica, phlogopite, biotite, and sericite. Further, as the synthetic mica, non-swelling mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li Tenniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , Montmorillonite Na or Li Hectorite (Na, Li) _1/8 Mg Swellable mica such as _2/5 Li _1/8 (Si ₄ O ₁₀ ) F ₂ can be used. Synthetic smectite is also useful.

Among the mica compounds, fluorine-based swellable mica, which is a synthetic layered compound, is particularly useful. That is, swellable clay minerals such as mica, montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, and metal atom substitution in the lattice is other than Significantly greater than viscous minerals. As a result, the lattice layer has a shortage of positive charges, and in order to compensate for this, organic cations such as Li ⁺ , Na ⁺ , Ca ²⁺ , Mg ²⁺ , amine salts, quaternary ammonium salts, phosphonium salts and sulfonium salts are provided between the layers. Adsorbs cations. These layered compounds swell with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have a strong tendency and are useful in the present invention. In particular, swellable synthetic mica is preferably used from the viewpoint of availability and uniformity of quality.

The shape of the layered compound is a flat plate, and from the viewpoint of diffusion control, the thinner the better, the larger the plane size as long as it does not hinder the smoothness of the coated surface or the transmittance of actinic rays. . Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle diameter of the layered compound, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. When the particle diameter is smaller than 0.3 μm, the suppression of permeation of oxygen and moisture is insufficient, and the effect cannot be sufficiently exhibited. On the other hand, if it is larger than 20 μm, the dispersion stability in the coating solution is insufficient, resulting in a problem that stable coating cannot be performed. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having such a large aspect ratio are contained in the protective layer, the coating film strength is improved, and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

Next, an example of a general dispersion method when a layered compound is used for the protective layer will be described.
First, 5 to 10 parts by mass of the swellable laminar compound mentioned above as a preferred laminar compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion containing 5 to 10% by mass of the inorganic layered compound dispersed by the above method is highly viscous or gelled, and has very good storage stability.
When preparing a coating solution for a protective layer using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of kinds of inorganic layered compounds are used in combination, it is preferable that the total amount of these inorganic layered compounds is compatible with the above-described mass ratio.

  As other additives for the protective layer, for example, glycerin, dipropylene glycol, propionamide, cyclohexanediol, sorbitol and the like are added in an amount corresponding to several mass% with respect to the water-soluble or water-insoluble polymer to give flexibility. be able to. Moreover, well-known additives, such as a water-soluble (meth) acrylic polymer and a water-soluble plasticizer, can be added for improving the physical properties of the film.

Further, the protective layer in the present invention is formed by using a protective layer coating solution as described later. This coating solution is used for improving the adhesion with the image forming layer and the stability over time of the coating solution. Known additives may be added.
That is, the protective layer coating solution includes an anionic surfactant, a nonionic surfactant, a cationic surfactant, and a fluorosurfactant for improving coating properties, specifically, sodium alkyl sulfate, alkyl sulfonic acid. Anionic surfactants such as sodium; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ether can be added. The addition amount of the surfactant can be 0.1 to 100% by mass with respect to the water-soluble or water-insoluble polymer.

  In order to improve the adhesion with the image area, for example, JP-A-49-70702 and UK Patent Application No. 1303578 include a hydrophilic polymer mainly composed of polyvinyl alcohol, an acrylic emulsion, It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass of a water-insoluble vinylpyrrolidone-vinyl acetate copolymer and laminating the mixture on an image forming layer. Any of these known techniques can be used in the present invention.

  Furthermore, other functions can be imparted to the protective layer. For example, by adding a colorant (for example, a water-soluble dye) that is excellent in the transparency of infrared rays used for exposure and that can efficiently absorb light of other wavelengths, safe light is not caused. Suitability can be improved.

The protective layer is formed by applying and drying a protective layer coating solution prepared by dispersing or dissolving the protective layer component in a solvent on the image forming layer.
The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water.

The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied.
Specifically, for example, when the protective layer is formed, a blade coating method, an air knife coating method, a gravure coating method, a roll coating coating method, a spray coating method, a dip coating method, a bar coating method, or the like is used.

The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.02 to 3 g / ^{m 2,} more preferably in the range of 0.05 to 1 g / ^{m 2,} and most preferably 0. The range is 1 to 0.4 g / m ² .

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

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

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

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Moreover, the transfer method which transfers an uneven | corrugated shape with the roll which provided the unevenness | corrugation in the rolling stage of aluminum can also be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A No. 54-63902.

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

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

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is. However, in order to further improve the adhesiveness with the upper layer, hydrophilicity, dirt resistance, heat insulation and the like. If necessary, the surface of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365 may be enlarged or sealed, and the surface may be immersed in an aqueous solution containing a hydrophilic compound. A hydrophilic treatment or the like can be appropriately selected and performed. Of course, the enlargement process and the sealing process are not limited to those described above, and any conventionally known methods can be performed. For example, as the sealing treatment, in addition to the vapor sealing, a single treatment with fluorinated zirconic acid, a treatment with sodium fluoride, and a vapor sealing with addition of lithium chloride are possible.

  The sealing treatment used in the present invention is not particularly limited, and a conventionally known method can be used. Among them, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and hot water. Sealing treatment is preferred. This will be described in detail below.

<1> Sealing treatment with an aqueous solution containing an inorganic fluorine compound As the inorganic fluorine compound used for the sealing treatment with an aqueous solution containing an inorganic fluorine compound, a metal fluoride is preferably exemplified.
Specifically, for example, sodium fluoride, potassium fluoride, calcium fluoride, magnesium fluoride, sodium fluoride zirconate, potassium fluoride zirconate, sodium fluoride titanate, potassium fluoride titanate, zircon fluoride Ammonium acid, ammonium fluorinated titanate, fluorinated zirconic acid, fluorinated titanic acid, hexafluorosilicic acid, nickel fluoride, iron fluoride, fluorinated phosphoric acid, and ammonium fluorinated phosphate. Of these, sodium fluorinated zirconate, sodium fluorinated titanate, fluorinated zirconic acid, and fluorinated titanic acid are preferable.

  The concentration of the inorganic fluorine compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, from the viewpoint of sufficiently sealing the micropores of the anodized film. Further, in terms of stain resistance, it is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  It is preferable that the aqueous solution containing the inorganic fluorine compound further contains a phosphate compound. When the phosphate compound is contained, the hydrophilicity of the surface of the anodized film is improved, so that the developability and stain resistance can be improved.

Suitable examples of the phosphate compound include phosphates of metals such as alkali metals and alkaline earth metals.
Specifically, for example, zinc phosphate, aluminum phosphate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, monoammonium phosphate, monopotassium phosphate, monosodium phosphate, dihydrogen phosphate Potassium, dipotassium hydrogen phosphate, calcium phosphate, sodium ammonium hydrogen phosphate, magnesium hydrogen phosphate, magnesium phosphate, ferrous phosphate, ferric phosphate, sodium dihydrogen phosphate, sodium phosphate, hydrogen phosphate Disodium, lead phosphate, diammonium phosphate, calcium dihydrogen phosphate, lithium phosphate, phosphotungstic acid, ammonium phosphotungstate, sodium phosphotungstate, ammonium phosphomolybdate, sodium phosphomolybdate, sodium phosphite , Tripolyphosphate Potassium, and sodium pyrophosphate. Of these, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate are preferable.
The combination of the inorganic fluorine compound and the phosphate compound is not particularly limited, but the aqueous solution contains at least sodium zirconate fluoride as the inorganic fluorine compound and contains at least sodium dihydrogen phosphate as the phosphate compound. Is preferred.

  The concentration of the phosphate compound in the aqueous solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of improving developability and stain resistance. In terms of solubility, it is preferably 20% by mass or less, and more preferably 5% by mass or less.

The ratio of each compound in the aqueous solution is not particularly limited, but the mass ratio of the inorganic fluorine compound and the phosphate compound is preferably 1/200 to 10/1, and preferably 1/30 to 2/1. Is more preferable.
The temperature of the aqueous solution is preferably 20 ° C. or higher, more preferably 40 ° C. or higher, preferably 100 ° C. or lower, more preferably 80 ° C. or lower.
The aqueous solution preferably has a pH of 1 or more, more preferably has a pH of 2 or more, preferably has a pH of 11 or less, and more preferably has a pH of 5 or less.
The method for sealing with an aqueous solution containing an inorganic fluorine compound is not particularly limited, and examples thereof include an immersion method and a spray method. These may be used alone or in combination, or may be used in combination of two or more.
Of these, the dipping method is preferred. When the treatment is performed using the dipping method, the treatment time is preferably 1 second or longer, more preferably 3 seconds or longer, and preferably 100 seconds or shorter, and 20 seconds or shorter. More preferred.

<2> Sealing treatment with water vapor Sealing treatment with water vapor includes, for example, a method in which pressurized or normal pressure water vapor is contacted with the anodized film continuously or discontinuously.
The temperature of the water vapor is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 105 ° C. or lower.
The water vapor pressure is preferably in the range (1.008 × 10 ^{5 to} 1.043 × 10 ⁵ Pa) from (atmospheric pressure−50 mmAq) to (atmospheric pressure + 300 mmAq).
Further, the time for which the water vapor is contacted is preferably 1 second or longer, more preferably 3 seconds or longer, 100 seconds or shorter, more preferably 20 seconds or shorter.

<3> Sealing treatment with hot water Examples of the sealing treatment with hot water include a method in which an aluminum plate on which an anodized film is formed is immersed in hot water.
The hot water may contain an inorganic salt (for example, phosphate) or an organic salt.
The temperature of the hot water is preferably 80 ° C. or higher, more preferably 95 ° C. or higher, and preferably 100 ° C. or lower.
Further, the time of immersion in hot water is preferably 1 second or longer, more preferably 3 seconds or longer, more preferably 100 seconds or shorter, and even more preferably 20 seconds or shorter.

  As the hydrophilization treatment, as described in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734 There is an alkali metal silicate method. In this method, the support is subjected to immersion treatment or electrolytic treatment with an aqueous solution such as sodium silicate. In addition, a method of treating with potassium fluoride zirconate described in JP-B 36-22063, a method of treating with polyacrylic acid as described in US Pat. No. 3,136,636, US Pat. And a method of treating with polyvinylphosphonic acid as described in US Pat. Nos. 3,276,868, 4,153,461 and 4,689,272. Among these, alkali metal silicate treatment and polyvinylphosphonic acid treatment are preferable, and polyvinylphosphonic acid treatment is more preferable.

  When using a support having insufficient surface hydrophilicity such as a polyester film as the support in the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. The hydrophilic layer includes at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A No. 2001-199175. An hydrophilic layer formed by applying a coating solution containing an oxide or hydroxide colloid, or an organic hydrophilic matrix obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A No. 2002-79772 A hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion consisting of hydrolysis and condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a surface containing a metal oxide A hydrophilic layer made of an inorganic thin film is preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

Moreover, when using a polyester film etc. as a support body in this invention, it is preferable to provide an antistatic layer in the hydrophilic layer side of a support body, the opposite side, or both sides. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles and a matting agent are dispersed as described in JP-A No. 2002-79772 can be used.

  The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the image forming layer, good printing durability and good stain resistance can be obtained.

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

(Back coat layer)
After surface treatment is performed on the support or after an undercoat layer (described later) is formed, a backcoat layer can be provided on the back surface of the support, if necessary.
As the back coat layer, for example, an organic polymer compound described in JP-A-5-45885, an organometallic compound or an inorganic metal compound described in JP-A-6-35174 is hydrolyzed and polycondensed. A coating layer made of the obtained metal oxide is preferable. Of these, the use of silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ is inexpensive. It is preferable in that it is easily available.

(Undercoat layer)
In the planographic printing plate precursor used in the present invention, an undercoat layer can be provided between the image forming layer and the support, if necessary.
Since the undercoat layer tends to cause the image forming layer to peel off from the support in the unexposed area, the developability is improved. In addition, in the case of infrared laser exposure, since the undercoat layer functions as a heat insulating layer, the heat generated by exposure does not diffuse to the support and can be used efficiently, so that the sensitivity can be increased. There is.

  Specific examples of the undercoat layer compound include a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, and JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group as described in 1 are mentioned suitably.

The compound used for the undercoat layer preferably has adsorptivity to the support surface. The presence or absence of adsorptivity to the support surface can be determined by the following method, for example.
A coating night is prepared by dissolving the test compound in a readily soluble solvent, and the coating night is coated and dried on the support so that the coating amount after drying is 30 mg / m ² . Next, after the support coated with the test compound is sufficiently washed with an easily soluble solvent, the residual amount of the test compound that has not been removed by washing is measured to calculate the support adsorption amount. Here, the measurement of the remaining amount may be performed by directly quantifying the amount of the remaining compound or by quantifying the amount of the test compound dissolved in the cleaning liquid. The compound can be quantified by, for example, fluorescent X-ray measurement, reflection spectral absorbance measurement, liquid chromatography measurement and the like. The compound having the support adsorptivity is a compound that remains at 1 mg / m ² or more even after the washing treatment as described above.

In order to give the compound used for the undercoat layer the adsorptivity to the support surface, it can be carried out by introducing a substrate adsorptive group (hereinafter also simply referred to as an adsorptive group). The adsorptive group is a substance (for example, metal, metal oxide) present on the support surface, or a functional group (for example, hydroxy group) and a chemical bond (for example, ionic bond, hydrogen bond, coordinate bond, intermolecular). It is a functional group that can cause binding by force. The adsorptive group is preferably an acid group or a cationic group.
The acid group preferably has an acid dissociation constant (pKa) of 7 or less. Examples of the acid group include a phenolic hydroxy group, a carboxyl group, —SO ₃ H, —OSO ₃ H, —PO ₃ H ₂ , —OPO ₃ H ₂ , —CONHSO ₂ —, —SO ₂ NHSO ₂ , —COCH _2. COCH ₃ is mentioned. Among them, -OPO ₃ H _2, and _-PO 3 _{H 2} are particularly preferred. These acid groups may be metal salts.
The cationic group is preferably an onium group. Examples of the onium group include an ammonium group, a phosphonium group, an arsonium group, a stibonium group, an oxonium group, a sulfonium group, a selenonium group, a stannonium group, and an iodonium group. Among these, an ammonium group, a phosphonium group, and a sulfonium group are preferable, an ammonium group and a phosphonium group are more preferable, and an ammonium group is most preferable.

  Preferable examples of the monomer having an adsorptive group used when synthesizing a polymer compound suitable as a compound for the undercoat layer include compounds represented by the following general formula (U1) or general formula (U2). .

In general formulas (U1) and (U2), R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms.
R ¹ , R ² , and R ³ are each independently preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Are more preferable, and a hydrogen atom or a methyl group is most preferable. R ² and R ³ are particularly preferably a hydrogen atom.
Z is a functional group adsorbed on the surface of the support and contains the adsorptive group.

L represents a single bond or a divalent linking group.
L is a divalent aliphatic group (alkylene group, substituted alkylene group, alkenylene group, substituted alkenylene group, alkynylene group, substituted alkynylene group), divalent aromatic group (arylene group, substituted arylene group) or divalent Or an oxygen atom (—O—), a sulfur atom (—S—), an imino (—NH—), a substituted imino (—NR—, R is an aliphatic group, an aromatic group Or a heterocyclic group) or a combination with carbonyl (—CO—).

The divalent aliphatic group may have a cyclic structure or a branched structure. The number of carbon atoms in the divalent aliphatic group is preferably 1 to 20, more preferably 1 to 15, and most preferably 1 to 10. The divalent aliphatic group is preferably a saturated aliphatic group rather than an unsaturated aliphatic group. Furthermore, the divalent aliphatic group may have a substituent, and examples of the substituent include a halogen atom, a hydroxy group, an aromatic group, and a heterocyclic group.
The number of carbon atoms of the divalent aromatic group is preferably 6 to 20, more preferably 6 to 15, and most preferably 6 to 10. In addition, the divalent aromatic group may have a substituent, and examples of the substituent include a halogen atom, a hydroxy group, an aliphatic group, an aromatic group, and a heterocyclic group.
The divalent heterocyclic group preferably has a 5-membered or 6-membered ring as a heterocycle. In addition, another heterocyclic ring, an aliphatic ring, or an aromatic ring may be condensed with the heterocyclic ring. The divalent heterocyclic group may have a substituent, and examples of the substituent include a halogen atom, a hydroxy group, an oxo group (═O), a thioxo group (═S), and an imino group (═NH). , Substituted imino groups (= N—R, R represents an aliphatic group, aromatic group or heterocyclic group), an aliphatic group, an aromatic group, or a heterocyclic group.

L is preferably a divalent linking group containing a plurality of polyoxyalkylene structures. The polyoxyalkylene structure is more preferably a polyoxyethylene structure. In other words, L preferably contains — (OCH ₂ CH ₂ ) _n — (n is an integer of 2 or more).
In General Formula (U1), X represents an oxygen atom (—O—) or imino (—NH—). X is preferably an oxygen atom.
In general formula (U2), Y represents a carbon atom or a nitrogen atom. When Y is a nitrogen atom and L is linked to Y to form a quaternary pyridinium group, Z itself is adsorbable, so Z is not essential, and Z may be a hydrogen atom.

  The example of the typical compound represented by general formula (U1) or general formula (U2) below is shown.

  The compound used for the undercoat layer preferably has a hydrophilic group. Examples of the hydrophilic group include a hydroxy group, a carboxyl group, a carboxylate group, a hydroxyethyl group, a polyoxyethyl group, a hydroxypropyl group, a polyoxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, an ammonium group, Preferred examples include an amide group, a carboxymethyl group, a sulfo group, and a phosphoric acid group. Of these, a sulfo group exhibiting high hydrophilicity is preferable.

Specific examples of the monomer having a sulfo group include methallyloxybenzenesulfonic acid, allyloxybenzenesulfonic acid, allylsulfonic acid, vinylsulfonic acid, p-styrenesulfonic acid, methallylsulfonic acid, acrylamide t-butylsulfonic acid, Examples include 2-acrylamido-2-methylpropanesulfonic acid, sodium salt of (3-acryloyloxypropyl) butylsulfonic acid, and amine salt. Among these, 2-acrylamido-2-methylpropanesulfonic acid sodium salt is preferable from the viewpoint of hydrophilic performance and synthetic handling.

  The compound used for the undercoat layer preferably has a crosslinkable group. The crosslinkable group can improve the adhesion to the image area. In order to impart crosslinkability to the compound used in the undercoat layer, a crosslinkable functional group such as an ethylenically unsaturated bond is introduced into the side chain of the polymer compound, or the polar substituent of the polymer compound is countercharged. Or a compound having an ethylenically unsaturated bond can be introduced by forming a salt structure.

  Examples of polymers having an ethylenically unsaturated bond in the side chain are polymers of esters or amides of acrylic acid or methacrylic acid, wherein the ester or amide residue (R of —COOR or —CONHR) is ethylenic. Mention may be made of polymers having unsaturated bonds.

Examples of the residue (the R) having an ethylenically unsaturated _{bond, -CH = CH 2, -C (} CH 3) = CH 2, - (CH 2) n CR 1 = CR 2 R 3, - ( ^{_{CH 2 O) n CH 2 CR}} 1 = CR 2 R 3, - (CH 2 CH 2 O) n CH 2 CR 1 = CR 2 R 3, - (CH 2) n NH-CO-O-CH 2 CR 1 ^{_{= CR 2 R 3, - (}} CH 2) n -O-CO-CR 1 = CR 2 R 3, and _{(CH 2 CH 2 O) 2} -X ( ^wherein, R 1 to R ³ are each a hydrogen atom Represents a halogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkoxy group or an aryloxy group, and R ¹ and R ² or R ³ may be bonded to each other to form a ring. Represents an integer of 1 to 10. X represents a dicyclopentadienyl residue. Can be mentioned.
Specific examples of the ester residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ (described in Japanese Patent Publication No. 7-21633), —CH. _{2 CH 2 O-CH 2 CH} = CH 2, -CH 2 C (CH 3) = CH 2, -CH 2 CH = CH-C 6 H 5, -CH 2 CH 2 OCOCH = CH-C 6 H 5, _{-CH 2 CH 2 NHCOO-CH 2} CH = CH 2, and _CH 2 _CH (wherein, X represents a dicyclopentadienyl residue.) 2 O-X and the like.
Specific examples of the amide residue include —CH═CH ₂ , —C (CH ₃ ) ═CH ₂ , —CH ₂ CH═CH ₂ , —CH ₂ CH ₂ O—Y (wherein Y is a cyclohexene residue) the _{represented), -. CH 2 CH 2} OCO-CH = CH 2 and the like.
As the monomer having a crosslinkable group of the polymer compound for the undercoat layer, an ester or amide of acrylic acid or methacrylic acid having the crosslinkable group is preferable.

  The content of the crosslinkable group in the undercoat layer compound (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1. 0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol. Within this range, both good sensitivity and dirtiness and good storage stability can be obtained.

  Preferred compounds for the undercoat layer in the present invention include compounds having a substrate adsorptive group and a crosslinkable group. Such a compound includes a compound obtained by polymerizing at least a monomer having an adsorptive group and a monomer having a crosslinkable group.

The polymer compound for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000, and a number average molar mass of 1000 or more is preferable. More preferably, it is ˜250,000. The polydispersity (mass average molar mass / number average molar mass) is preferably 1.1 to 10.
The polymer compound for the undercoat layer may be any of a random polymer, a block polymer, a graft polymer and the like, but is preferably a random polymer.

The undercoat compound may be used alone or in combination of two or more.
The undercoat layer coating solution is obtained by dissolving the above undercoat compound in an organic solvent (for example, methanol, ethanol, acetone, methyl ethyl ketone, etc.) and / or water.
The undercoat layer coating solution may contain an infrared absorber.
Various known methods can be used as a method of applying the undercoat layer coating solution to the support. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
The coating amount (solid content) of the undercoat layer is preferably from 0.1 to 100 mg / m ² , and more preferably from ¹ to 30 mg / m ² .

  The lithographic printing plate produced as described above is mounted on a plate cylinder of a printing press, and a large number of printed materials can be provided by supplying dampening water and printing ink.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

<Glossary of Chemical Substances Used in the Synthesis of Polymer Particles of the Present Invention and Image Forming Layer Coating Solutions> BYK 336: Modified dimethylpolysiloxane copolymer available from Byk-Chemie USA Inc. (Wallingford, Connecticut) DESMODUR N100: aliphatic polyisocyanate resin based on hexamethylene diisocyanate available from Bayer Corp. (Milford, Connecticut)
ELVACITE 4026: 10% 2-butanone solution of hyperbranched poly (methyl methacrylate) available from Lucite International, Inc. (Cordova, Tennessee) Hydroxypropylcellulose: hydroxypropylcellulose from Wako Pure Chemical Industries 2% aqueous solution 1,000-4,000 cP
Mercapto-3-triazole: Mercapto-3-triazole-1H, 2,4 available from PCAS (Paris, France)
PEGMA: 50% by weight aqueous solution of poly (ethylene glycol) methyl ether methacrylate available from Sigma-Aldrich Corp. (St. Louis, Missouri), average Mn-2080
・ SARTOMER 355: Ditrimethylolpropane tetraacrylate available from Sartomer Japan ・ Urethane acrylate: 80% 2-butanone solution of urethane acrylate obtained by reaction of DESMODUR N100 with hydroxyethyl acrylate and pentaerythritol triacrylate ・ V- 601: Wako Pure Chemical Industries 2,2'-azobis (dimethyl 2-methylpropanoate)

<Synthesis of Polymer Fine Particle 1 of the Present Invention>
A mixture of 54 g n-propanol and 16 g deionized water was placed in a 250 mL flask, heated to 70 ° C., purged with a steady stream of N ₂ gas, and stirred with a mechanical stirrer.

  Prepare a mixture of 54 g n-propanol, 16 g deionized water, 10 g PEGMA, 4.5 g styrene, 40.5 g acrylonitrile and 0.32 g V-601 in a separate beaker, and then add this mixture to 30 It was added dropwise to the 250 mL flask over a period of minutes. After 2.5 hours, 0.16 g of V-601 was added to the reaction mixture. The polymerization reaction was carried out for another 2 hours. The obtained polymer solution contained 21% by mass of polymer fine particles 1.

When the particle size of the obtained polymer fine particle 1 was measured using a laser diffraction / scattering particle size distribution analyzer LA-910 manufactured by Horiba, ma (average diameter of area distribution) was 364 nm, mv (volume distribution) The average diameter of the distribution (the center of gravity of the distribution) was 440 nm.

Moreover, when molecular weight was measured in the tetrahydrofuran using gel permeation chromatography, _Mw (mass mean molar mass) was 129,000.

<Synthesis of Polymer Fine Particle 2 of the Present Invention>
A mixture of 54 g n-propanol and 16 g deionized water was charged into a 250 mL flask, which was heated to 70 ° C., purged with a steady stream of N ₂ gas, and mechanically stirred. Stir. Prepare a mixture of 54 g n-propanol, 16 g deionized water, 10 g PEGMA, 6.75 g styrene, 38.25 g acrylonitrile, and 0.48 g V-601 in a separate beaker and Added dropwise to a 250 mL flask over 30 minutes. After 2.5 hours, 0.16 g of V-601 was added to the reaction mixture. The polymerization reaction lasted for a total of 19 hours. The resulting polymer solution contained 24% by weight solids polymer particles 2.

<Synthesis of Polymer Fine Particle 3 of the Present Invention>
A mixture of 54 g n-propanol and 16 g deionized water was placed in a 250 mL flask, heated to 70 ° C., purged with a steady stream of N ₂ gas, and stirred with a mechanical stirrer. Prepare a mixture of 54 g n-propanol, 16 g deionized water, 10 g PEGMA, 13.5 g styrene, 31.5 g acrylonitrile and 0.48 g V-601 in a separate beaker, It was added dropwise to the 250 mL flask over a period of minutes. After 2.5 hours, 0.16 g of V-601 was added to the reaction mixture. The polymerization reaction was carried out for another 2 hours. The obtained polymer solution contained 21.7% by mass of polymer fine particles 3.
When the particle size of the obtained polymer fine particles 3 was measured by the above method, ma = 617 nm and mv = 670 nm were obtained.

<Synthesis of Polymer Fine Particle 4 of the Present Invention>
A solution of 20 g PEGMA dissolved in a mixture of 190 g deionized water and 200 g n-propanol is placed in a 1000 mL four-necked flask until slightly refluxed under N ₂ atmosphere ( Heat slowly (~ 73 ° C). To this was added a mixture of styrene (9 g), acrylonitrile (81 g) and V-601 (0.7 g) over 2 hours. After 6 hours, additional V-601 (0.5 g) was added. The temperature was raised to 80 ° C. Subsequently, V-601 was added twice more (each 0.35 g) every 3 hours. The total reaction time was 19 hours. The conversion to copolymer was> 98% by weight, based on measurement of percent non-volatile content. The mass ratio of PEGMA / styrene / acrylonitrile was 10: 9: 81 and the n-propanol / water ratio was 50:50. Residual acrylonitrile in the solution was 0.08% by mass based on measurement by ¹ H-NMR.
When the particle size and molecular weight of the obtained polymer fine particles 4 were measured by the above method, ma = 188 nm, mv = 225 nm, and Mw = 19.3 million.

<Synthesis of Polymer Fine Particle 5 of the Present Invention>
A solution of 20 g PEGMA dissolved in a mixture of 74.8 g deionized water and 241.4 g n-propanol was placed in a 1000 mL four-necked flask until slightly refluxed under N ₂ atmosphere ( (76 ° C.) Slowly heated. To this was added a mixture of styrene (20 g), acrylonitrile (70 g) and V-601 (0.7 g) over 2 hours. After 6 hours, additional V-601 (0.5 g) was added. The temperature was raised to 80 ° C. Subsequently, V-601 was added twice more (each 0.35 g) every 3 hours. The total reaction time was 19 hours. The conversion to copolymer was> 98% by weight, based on measurement of percent non-volatile content. The mass ratio of PEGMA / styrene / acrylonitrile was 10:20:70, and the n-propanol / water ratio was 76:24. The residual acrylonitrile in the solution was 0.5% by mass based on measurement by ¹ H-NMR.

<Synthesis of Polymer Fine Particle 6 of the Present Invention>
A mixture of 50 g water and 2.5 g PEGMA was placed in a 250 mL three neck flask equipped with a magnetic stirrer, temperature controller, addition funnel and N ₂ inlet and heated to 70 ° C. with stirring.
To this was added a first monomer containing 2.1 g of methacrylonitrile, followed by 0.05 g of ammonium persulfate. The mixture was stirred for about 30 minutes at 70 ° C. and an additional 0.05 g ammonium persulfate was added. A second monomer mixture containing 17 g methacrylonitrile, 13 g n-propanol and 1.9 g styrene was added slowly over 2 hours. 0.05 g of ammonium persulfate was added and the mixture was stirred at 70 ° C. overnight (˜20 hours). The obtained polymer solution contained 13.7% by mass of polymer fine particles 6.
When the particle size and molecular weight of the obtained polymer fine particles 6 were measured by the above method, ma = 282 nm, mv = 371 nm, the molecular weight showed a distribution having two peaks, and Mw = 12.3 million, It was 68.3 million.

<Synthesis of Polymer Fine Particle 7 of the Present Invention>
Add a mixture of 0.05 g ammonium persulfate, 10 g water and 10 g n-propanol to a 50 mL three-necked flask equipped with a magnetic stirrer, addition funnel and N ₂ inlet with 1.25 g PEGMA Heated to 70 ° C. under N ₂ atmosphere. A solution containing 1.0 g styrene and 4.0 g methacrylonitrile was slowly added to the three-necked flask via the addition funnel over 1.5 hours with stirring and the temperature was maintained at about 70 ° C. After 5 hours, an additional 0.04 g of ammonium persulfate was added. The reaction was stirred at 70 ° C. overnight (˜20 hours). The obtained polymer solution contained 15.6% by mass of polymer fine particles 7.
When the particle size and molecular weight of the obtained polymer fine particle 7 were measured by the above method, ma = 423 nm, mv = 724 nm, the molecular weight showed a distribution having two peaks, and Mw = 57,000, It was 716,000.

<Synthesis of Comparative Polymer Fine Particle 1>
A mixture of 15 g PEGMA, 48 g water and 192 g 1-propanol was placed in a 500 mL flask and heated to 80 ° C. In a separate beaker, 66.9 g styrene and 0.48 g V-601 were mixed and a portion of this solution (12 g) was added to the mixture in the flask. The mixture became cloudy within about 10 minutes. Subsequently, the remaining solution was added to the flask over 30 minutes. After further 3 hours, the obtained polymer solution contained 25% by mass of polymer fine particles 1 for comparative example.
When the particle size and molecular weight of the obtained polymer fine particles 1 for Comparative Example were measured by the above-described methods, ma = 268 nm, mv = 335 nm, and Mw = 15.7 thousand.

<Synthesis of Comparative Polymer Fine Particle 2>
A mixture of 54 g n-propanol and 16 g deionized water was placed in a 250 mL flask, heated to 70 ° C., purged with a steady stream of N ₂ gas, and stirred with a mechanical stirrer. Separated from 54 g of n-propanol, 16 g of deionized water, 0.8 g of Pionine A-41C (manufactured by Takemoto Yushi Co., Ltd.), 6.75 g of styrene, 38.25 g of acrylonitrile and 0.48 g of V-601 Prepared in a beaker and added dropwise to the 250 mL flask over 30 minutes. After 2.5 hours, 0.16 g of V-601 was added to the reaction mixture. The polymerization reaction was carried out for a total of 19 hours. The resulting polymer solution contained 22.5% by weight of comparative polymer fine particles 2.

<Synthesis of other binder polymer 2>
2-butanone (384.1 g) and 8.5 g of PEGMA were placed in a 1 L four-necked flask under N ₂ atmosphere and heated to 80 ° C. To this, a mixture of allyl methacrylate (38.0 g) and V-601 (0.3 g) was added at 80 ° C. over 90 minutes. After the addition was completed, an additional 0.13 g of V-601 was added. Thereafter, 0.13 g of V-601 was added two more times. The polymer conversion based on percent nonvolatiles was> 98% by weight.
When the molecular weight of the other binder polymer 2 obtained was measured by the above method, it was Mw = 45,000.

[Examples 1 to 33 and Comparative Examples 1 to 15]
<Preparation of lithographic printing plate precursor (1)>
(1) Production of support (1) In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, degreasing is performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution. After the treatment, the aluminum surface was grained with three bundle-planted nylon brushes having a bristle diameter of 0.3 mm and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm. Washed well. This plate was etched by being immersed in a 25 mass% aqueous sodium hydroxide solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying. An aqueous solution (containing 0.5% by mass of aluminum ions) was used as an electrolytic solution to provide a 2.5 g / m ² direct current anodized film at a current density of 15 A / dm ² , and then washed and dried.
Further, water vapor at 100 ° C. was changed to 1.033.
Next, sealing was performed by spraying this plate on the anodic oxide film for 8 seconds under a pressure of 15 mass% sulfuric acid × 10 ⁵ Pa.
Then, in order to ensure the hydrophilic property of a non-image part, the silicate process was performed for 6 second at 75 degreeC using 2.5 mass% 3 sodium silicate aqueous solution. The adhesion amount of Si was 10 mg / m ² . Then, it washed with water and the support body (1) was obtained. The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support (1) so that the dry coating amount is 20 mg / m ² , and a support having an undercoat layer. Was made.

[Coating liquid for undercoat layer (1)]
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Methanol 55.24g
・ Water 6.15g

(3) Formation of image forming layer After the image forming layer coating liquid (1) having the following composition was bar coated on the undercoat layer, it was oven dried at 100 ° C. for 60 seconds, and the dry coating amount was 1.0 g / m ² . An image forming layer was formed.
As shown in Table 1, the image forming layer coating solution (1) is mixed and stirred immediately before coating, as shown in Table 1, with respect to 10.467 g of the following photosensitive solution (1). It was prepared by.

[Photosensitive solution (1)]
-Other binder polymer (1) below 0.240g
・ The following infrared absorber (1) 0.030 g
・ The following polymerization initiator (A) 0.162 g
・ Polymerizable compound (tris (acryloyloxyethyl) isocyanurate)
(NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Pionine A-20 (Takemoto Yushi Co., Ltd.) 0.055g
・ Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
・ The following fluorosurfactant (1) 0.008g
・ Methyl ethyl ketone 1.091g
・ 1-methoxy-2-propanol 8.609g

(3) Formation of Protective Layer After the protective layer coating solution (1) having the following composition was bar-coated on the image forming layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m ² . A protective layer was formed to obtain a lithographic printing plate precursor (1).

[Coating liquid for protective layer (1)]
-1.5 g of the following inorganic layered compound dispersion (1)
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
-Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd., saponification degree: 81.5 mol%,
Degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

-Preparation of inorganic layered compound dispersion (1)-
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

<Preparation of lithographic printing plate precursor (2)>
(1) Production of Support (2) An aluminum plate that has been subjected to electrochemical surface roughening in the production of support (1) is prepared by using 2.5M phosphoric acid as an electrolyte, voltage 50V, and maximum current density 2A. in / dm ² to provide a DC anodic oxide film of 1.5 g / ^{m 2,} washed with water and dried.
Then, 100 degreeC water vapor | steam was sprayed on said anodic oxide film for 15 second by the pressure of 1.033 * 10 < ⁵ > Pa, and the sealing process was performed.
Then, it was immersed in a polyacrylic acid aqueous solution with a liquid temperature of 25 ° C. and 1.0 mass% for 8 seconds, washed with water and dried to obtain a support (2).

(2) Formation of undercoat layer, image forming layer and protective layer A lithographic plate except that the image forming layer coating solution (1) was changed to the image forming layer coating solution (2) described below using the support (2). In the same manner as in the case of the printing plate precursor (1), an undercoat layer, an image forming layer and a protective layer were provided to obtain a lithographic printing plate precursor (2).
As shown in Table 1, the image forming layer coating solution (2) was mixed and stirred immediately before coating, as shown in Table 1, with respect to 87.19 g of the following photosensitive solution (2). It was prepared by.

[Photosensitive solution (2)]
-Other binder polymer 2 3.97g
・ Urethane acrylate 2.48g
-0.32 g of the following polymerization initiator (B)
・ The following infrared absorber (2) 0.13 g
・ Mercapto-3-triazole 1.00g
・ BYK336 0.60g
・ Hydroxypropylcellulose 3.31 g
・ N-propanol 61.97 g
・ Water 13.41g

<Preparation of lithographic printing plate precursor (3)>
(1) Production of Support (3) The polyacrylic acid treatment in the production of the support (2) was changed to a polyvinylphosphonic acid treatment. That is, the aluminum plate that had been subjected to the treatment before the polyacrylic acid treatment in the production of the support (2) was immersed in a polyvinylphosphonic acid aqueous solution at a liquid temperature of 50 ° C. and 0.4 mass% for 10 seconds, washed with water, It dried and obtained the support body (3).

(2) Formation of image forming layer The following image forming layer coating solution (3) was applied to the support (3) without providing an undercoat layer, followed by oven drying at 90 ° C. for 90 seconds and a dry coating amount of 1.5 g. / to obtain a lithographic printing plate precursor (3) an image forming layer m ² are provided. The lithographic printing plate precursor (3) was not provided with a protective layer.

[Image forming layer coating solution (3)]
-Polymer fine particles of the present invention described in Table 1 13.79 g
・ Urethane acrylate 2.48g
・ ELVACITE 4026 3.31g
・ 0.32 g of the above polymerization initiator (B)
・ The above infrared absorbing agent (2) 0.13 g
・ Mercapto-3-triazole 0.18g
・ BYK336 0.60g
・ Hydroxypropylcellulose 3.30g
・ SARTOMER 355 0.33g
・ N-propanol 62.42g
・ Water 13.37g

<Exposure>
The lithographic printing plate precursors (1) to (2) were exposed with a Luxel PLANETTER T-6000III equipped with an infrared semiconductor laser under the conditions of an outer drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi.
On the other hand, the lithographic printing plate precursor (3) was exposed with a Trendsetter 3244VX manufactured by Creo Corporation equipped with an infrared semiconductor laser under the conditions of an output of 10 W and an outer drum rotating speed of 150 rpm and a resolution of 2400 dpi. The exposure image includes a solid image and a fine line image, respectively.

<Development processing>
In Examples 1 to 29 and Comparative Examples 1 to 15, the exposed original plate was developed using the automatic developing apparatus shown in FIG. In FIG. 1, development in the developing unit 14, washing in the washing unit 16, washing in the desensitization processing unit 18, desensitization in the developer, washing water and desensitizing solution as shown in Table 1 below. It was performed using.
The developer was passed through a cartridge filter “TCW-75N-PPS” (mesh diameter: 75 μm) manufactured by ADVANTEC and circulated using a pump.

In Examples 30 to 33, the exposed original plate was developed using an automatic developing apparatus shown in FIG. 2 and then dried with a drier. In Examples 30 and 32, this automatic developing device was used alone, and in Examples 31 and 33, two units were connected.
Table 1 below shows the developers used.

<Evaluation>
The plate surface re-adhesiveness and fine line reproducibility of the development-removed component by the above development treatment were evaluated in the following manner. The evaluation results are shown in Table 1.

(1) Plate surface re-adhesiveness of development removal component The surface of the lithographic printing plate after the above development treatment was visually observed, and the degree of re-deposition of the removal component of the image forming layer was evaluated by the following index.
A: Very good with no reattachment of removed components.
B: Although a slight removal component is observed, it can be easily removed with a waste cloth or the like and is at an acceptable level.
C: Many removed components, and cannot be easily removed by wiping with a waste cloth.
D: Re-adhesion of removed components is extremely large and inferior.

(2) Fine line reproducibility The developed lithographic printing plate was attached to the plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) Printing was started by supplying dampening water and ink by the standard automatic printing start method of LITHRONE 26, and printing was performed on 100 sheets of Tokishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.

  As a method for evaluating whether or not the non-image area image forming layer is removed according to the desired image in the development process, an exposed fine line image (white fine lines (in the image area from 5 μm to 50 μm) The thickness of the thin white line that is reproduced by visually observing the printed matter of the 100th sheet, indicating how thick the white thin line can be reproduced on the printing paper by changing the thickness of the thin line non-image portion)) I evaluated it. That is, a smaller value indicates that a finer fine line is well developed, and a preferable result is shown. The results are shown in Table 1.

  From the results of Table 1, in any of Examples 1 to 33 using the method for preparing a lithographic printing plate of the present invention, lithographic printing excellent in fine line reproducibility was successfully prevented from re-adhering the plate surface of the development removal component. It turns out that a plate is obtained.

[Composition of processing solution used in development process]
<Treatment liquid 1 (pH: 9.7)>
8329.8g of water
Sodium carbonate 130g
Sodium bicarbonate 70g
New Call B13 500g
(Nippon Emulsifier Co., Ltd. Polyoxyethylene β-naphthyl ether)
Gum arabic 250g
700g of hydroxyalkylated starch (Nissho Chemical: Penon JE66)
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3diol 0.1g
2-Methyl-4-isothiazolin-3-one 0.1g

<Treatment liquid 2 (pH: 9.5)>
9109.8g of water
Sodium carbonate 200g
Sodium bicarbonate 140g
Pionein D3110 450g
150g of cellulose
Enzymatic degradation dextrin (Nissho Chemical: Amycol) 600g
Citric acid 40g
20g of primary ammonium phosphate
Propylene glycol 80g
2-Bromo-2-nitropropane-1,3diol 0.1g
2-Methyl-4-isothiazolin-3-one 0.1g

<Treatment liquid 3 (pH: 9.5)>
8150g of water
Sodium carbonate 160g
Sodium bicarbonate 160g
Pionein C157K (100% conversion) 500g
Polyvinylpyrrolidone (Nippon Catalyst: Polyvinylpyrrolidone) 850g
180g sodium hexametaphosphate

<Treatment solution 4 (pH: 9.9)>
9379.8g of water
Sodium carbonate 130g
Sodium bicarbonate 70g
New Call B13 500g
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3diol 0.1g
2-Methyl-4-isothiazolin-3-one 0.1g

<Aqueous solution 1 of comparative example (pH: 7.0)>
9379.8g of water
New Call B13 500g
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3diol 0.1g
2-Methyl-4-isothiazolin-3-one 0.1g

<Aqueous solution 2 of comparative example (pH: 11.9)>
8498.8g of water
Potassium carbonate 17g
KOH (48%) 14g
New Call B13 500g
Gum arabic 250g
700g of hydroxyalkylated starch (Nissho Chemical: Penon JE66)
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3diol 0.1g
2-Methyl-4-isothiazolin-3-one 0.1g

[Water quality of the washing water used in the washing process]
<Fresh water>: Always use new tap water. (No reuse)
<Circulating water>: Reused water circulated using a pump. Once used for water washing, it is reused after passing through a cartridge filter “TCW-75N-PPS” (mesh diameter: 75 μm) manufactured by ADVANTEC.

[Gum solution for desensitizing process]
A gum solution “FN-6” manufactured by FUJIFILM Corporation is diluted with an equal amount of tap water.

[Examples 34 to 48 and Comparative Examples 16 to 30]
<Preparation of lithographic printing plate precursor (4)>
The photosensitive solution (1) in the preparation of the lithographic printing plate precursor (1) was changed to a photosensitive solution (4) having the following composition, and the polymer fine particle dispersion of the present invention was 1. A lithographic printing plate precursor (4) was obtained in the same manner as in the preparation of the lithographic printing plate precursor (1) except that 50 g was used as described in Table 2.

[Photosensitive solution (4)]
・ The following polymerization initiator (1) 0.18 g
-The following sensitizing dye (1) (absorption maximum wavelength; 359 nm) 0.06 g
・ Other binders (1) 0.54g
・ Polymerizable compound (Aronix M-315, manufactured by Toa Gosei Co., Ltd.) 0.45 g
・ Royco Crystal Violet 0.20g
・ Thermal polymerization inhibitor 0.01g
(N-nitrosophenylhydroxylamine aluminum salt)
・ Pionine A-20 (Takemoto Yushi Co., Ltd.) 0.05 g
-Fluorosurfactant (1) 0.001g
・ Methyl ethyl ketone 3.50g
・ 1-Methoxy-2-propanol 8.00 g

<Exposure>
The lithographic printing plate precursor (4) was image-exposed with a FFEI Violet semiconductor laser plate setter Vx9600 (with an InGaN-based semiconductor laser (with an emission wavelength of 405 nm ± 10 nm / output 30 mW)). The image was drawn with a resolution of 2438 dpi and an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., with a plate surface exposure of 0.05 mJ / cm ² .
The exposure image includes the solid image and the fine line image.

<Development processing and evaluation>
When the development processing and evaluation shown in Table 2 were performed in the same manner as in Examples 1 to 33, the results shown in Table 2 were obtained. From the results of Table 2, in any of Examples 34 to 48 using the method for preparing a lithographic printing plate of the present invention, lithographic printing excellent in fine line reproducibility was successfully prevented from reattaching the plate surface of the development removal component. It turns out that a plate is obtained.

It is a figure which shows the structure of the automatic image development apparatus of the lithographic printing plate precursor concerning this invention. FIG. 2 is a diagram illustrating a configuration of an automatic developing apparatus having only a developing unit according to the present invention.

Explanation of symbols

(Figure 1)
DESCRIPTION OF SYMBOLS 12 Printing plate precursor 14 Developing part 16 Washing part 18 Desensitizing process part 20 Drying part 24 Developing tank 141,142 Brush roll (rubbing member)
200 Pre-processing unit (Fig. 2)
DESCRIPTION OF SYMBOLS 1 Rotating brush roll 2 Receiving roll 3 Conveying roll 4 Conveying guide plate 5 Spray pipe 6 Pipe line 7 Filter 8 Feed plate 9 Discharge plate 10 Developer tank 11 Circulation pump 12 Printing plate precursor

Claims (14)

A method for preparing a lithographic printing plate having an image forming layer comprising a polymer fine particle containing a repeating unit having a polyalkylene oxide segment in a side chain and a repeating unit having a cyano group in a side chain on a support, the following steps: A method for preparing a lithographic printing plate comprising (a) and (b).
(A) A step of exposing the lithographic printing plate precursor imagewise.
(B) A step of developing the exposed lithographic printing plate precursor with an aqueous solution of pH 8.5 to 10.5 containing carbonate ions and hydrogen carbonate ions.   The method for producing a lithographic printing plate according to claim 1, wherein the aqueous solution used in the developing step (b) further contains a water-soluble polymer compound.   The method for preparing a lithographic printing plate according to claim 2, wherein the water-soluble polymer compound is gum arabic or starch.   The method for preparing a lithographic printing plate according to any one of claims 1 to 3, wherein the aqueous solution used in the developing step (b) further contains a surfactant.   The method of preparing a lithographic printing plate according to any one of claims 1 to 4, wherein the developing step (b) is performed using an automatic processor having a rubbing member.   The method for preparing a lithographic printing plate according to any one of claims 1 to 5, wherein the developing step (b) is continuously performed twice or more.   The lithographic printing plate preparation according to any one of claims 1 to 6, further comprising (c) a step of washing the developed lithographic printing plate precursor surface with water after the developing step (b). Method.   The method for preparing a lithographic printing plate according to any one of claims 1 to 7, wherein the aqueous solution used in the developing step (b) is repeatedly used through a filter.   2. The image forming layer further comprises (A) a sensitizing dye, (B) a polymerization initiator, and (C) a polymerizable compound, and the exposure step (a) is performed by laser irradiation. The preparation method of the lithographic printing plate as described in any one of -8.   The method for preparing a lithographic printing plate according to claim 9, wherein (A) the sensitizing dye is a water-soluble cyanine dye, and (B) the polymerization initiator is a water-soluble onium salt.   The lithographic printing plate precursor has a protective layer on the image forming layer, and the protective layer contains 10 to 50% by mass of anion-modified polyvinyl alcohol in the total solid content of the protective layer. The method for producing a lithographic printing plate according to any one of 10 to 10.   The lithographic printing plate precursor has an undercoat layer between the support and the image forming layer, and the undercoat layer contains a compound having a substrate adsorptive group and a crosslinkable group in the molecule. The method for producing a lithographic printing plate according to any one of claims 1 to 11.   The method for preparing a lithographic printing plate according to any one of claims 1 to 12, wherein the support is an anodized support using phosphoric acid. The method for preparing a lithographic printing plate according to any one of claims 1 to 13, wherein the support is a support hydrophilized using polyvinylphosphonic acid.

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