JP4333312B2 - Photosensitive planographic printing plate processing method and plate surface protective agent - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a processing method and a plate surface protective agent for a photosensitive lithographic printing plate, and in particular, a plate surface protection processing method for a lithographic printing plate after exposing and developing a photopolymerization type photosensitive lithographic printing plate, and a plate surface protection used in the processing method. It relates to a treating agent.

  In the field of printing today, an offset printing method using a photosensitive lithographic printing plate is widely used. In general, in this offset printing method, a photosensitive lithographic printing plate is image-exposed and then developed, and an image portion that receives printing ink and a non-image portion that receives water and does not receive printing ink are printed on the printing plate. Formed on top and used for printing. In this process, the developed printing plate is treated with a plate surface protective agent in order to protect the surface of the printing plate mainly after the above development and before printing or during printing. ing.

  The purpose of processing with this plate surface protective agent is mainly to maintain the hydrophilicity of the non-image area during the period from development to printing, and rewriting, erasing, etc. of the image area performed before development and printing. This prevents image smudges caused by adhesion of fingerprints, oils and fats, dust, etc. that occur during the handling of the printing plate in the process of attaching to the printing press, and prevents scratches. For example, it is possible to prevent contamination due to oxidation of the image area.

  Conventionally, as a plate surface protecting agent for a lithographic printing plate, generally gum arabic, cellulose gum or an aqueous solution of a water-soluble polymer having a carboxyl group in the molecule is used.

  In addition, a plate surface protective agent containing phosphoric acid-modified starch is described in JP-A-62-11693, and a plate surface protective agent containing carboxyalkylated starch is described in JP-A-62-27595. A plate surface protecting agent containing starch modified with its derivatives (including phosphonic acid) is known (see Patent Document 1).

  Also, a plate surface protective agent containing a specific polyoxyethylene group-containing activator (see Patent Document 2), a plate surface protective agent containing a hydrocarbon having a specific structure (see Patent Document 3), or a soybean polysaccharide and an aldehyde compound Is known, and it is known that these plate surface protecting agents contain a phosphonic acid compound as a chelating agent.

  On the other hand, the support of the photosensitive lithographic printing plate is required to have excellent hydrophilicity, water retention, and adhesiveness with the photosensitive layer from the viewpoint of printability. An aluminum plate that has been subjected to a roughening treatment called graining is used. As a developer of a printing plate material using an aluminum plate as a support, a developer containing a silicate is used for pH buffering, hydrophilicity, etc., but when a large number of printing plate materials are processed, In some cases, sludge was generated that would cause smudging during printing.

  On the other hand, as a photosensitive layer, a photosensitive layer containing a polymerizable ethylenic double bond-containing compound is known, and a polymerization type photosensitive lithographic printing plate provided on an aluminum plate support has a sensitivity. It is known that it can be advantageously used from the viewpoint of printing durability.

However, a polymerization type photosensitive lithographic printing plate using an aluminum plate as a support is excellent in printing durability as described above. However, when a large number of sheets are developed by an ordinary automatic processor, it is not particularly effective when printing is resumed. In some cases, the image portion is likely to be stained, and the use of the above-mentioned plate surface protective agent is insufficient to solve these problems.
Japanese Unexamined Patent Publication No. Sho 62-11663 Japanese Patent Laid-Open No. 11-265074 JP-A-11-288106 JP 2003-182256 A

  An object of the present invention is to provide a post-processing method after development and a plate surface protective agent used for the post-processing, which prevents the non-image area from being smeared when resuming printing during printing using a polymerization type photosensitive lithographic printing plate. There is to do.

The object of the present invention is achieved by the following constitution.
(Claim 1)
After exposing and developing a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing a polymerizable ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support (A) A lithographic printing process comprising treating with a plate surface protective agent containing a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more, and then heating at 50 ° C. to 200 ° C. Plate processing method.
(Claim 2)
2. The method for processing a photosensitive lithographic printing plate according to claim 1, wherein the (B) phosphonic acid compound having a molecular weight of 2000 or more is a polyvinyl phosphonic acid compound.
(Claim 3)
2. The method for processing a photosensitive lithographic printing plate according to claim 1, wherein the (B) phosphonic acid compound having a molecular weight of 2000 or more is a phosphonic acid-modified starch.
(Claim 4)
The developer used for the development processing is a developer containing a surfactant having an oxyalkylene group and having a silicate content of 0 to 0.1% (SiO ₂ mass conversion). The processing method of the photosensitive lithographic printing plate of Claim 1 thru | or 3.
(Claim 5)
After exposing and developing a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing a polymerizable ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support A plate surface protecting agent for a photosensitive lithographic printing plate, comprising: (A) a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more.

  According to the configuration of the present invention, a post-development post-processing method and a plate surface protecting agent used for the post-treatment are provided that prevent the non-image area from being smeared when resuming printing when printing using a polymerization type photosensitive lithographic printing plate. it can.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to a specific plate surface protection comprising (A) a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more after developing a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer. It is a post-processing method after development characterized in that it is processed with an agent and then heated at 50 ° C. to 200 ° C.

  The present invention uses a plate surface protective agent containing a phosphonic acid compound having a different molecular weight as a plate surface protective agent, and heat treatment is performed at a specific temperature. This is intended to prevent the non-image area from becoming dirty.

  The phosphonic acid compound of the present invention is a compound containing a phosphonic acid group and a derivative group thereof and a salt thereof. The derivative group means, for example, a phosphonate group or an ester group.

  In the present invention, when the phosphonic acid compound is a polymer, the molecular weight means a number average molecular weight.

((A) phosphonic acid compound having a molecular weight of less than 2000)
(A) Phosphonic acid compounds having a molecular weight of less than 2000 include nitrilotris-methylene-phosphonic acid compounds such as aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), triethylenetetraminehexa (Methylene phosphonic acid), alkane polyamines such as hydroxyethylethylenediamine tri (methylene phosphonic acid), polymethylene phosphonic acid compounds, phosphonoalkane polycarboxylic acid compounds, hydroxyalkane phosphonic acid compounds such as 1-hydroxyethane-1,1-diphosphonic acid (Including these sodium salts, potassium salts and ammonium salts) are preferably used.

  A phosphonic acid compound having a molecular weight of less than 2000 preferably has a molecular weight of 1000 or less, and more preferably 500 or less. That is, an embodiment having a combination of a phosphonic acid compound having a molecular weight of 500 or less and a phosphonic acid compound having a molecular weight of 2000 or more is particularly preferred.

((B) phosphonic acid compound having a molecular weight of 2000 or more)
(B) As phosphonic acid compounds having a molecular weight of 2000 or more, polyvinylphosphonic acid, phosphonic acid-modified starch in which phosphonic acid (derivative) is ester-bonded to the hydroxyl group of glucose, phosphonic acid-modified polyvinyl alcohol, phosphonic acid-modified cellulose, phosphonic acid derivative poly Examples thereof include compounds containing a phosphonic acid group or a phosphonic acid ester group in the main chain or side chain of the polymer, such as acrylic acid.

  Among these, it is particularly preferable to use a polyvinylphosphonic acid compound and a phosphonic acid-modified starch.

  As content of the said phosphonic acid compound, it is preferable to exist in 0.001-5 mass% with respect to a plate surface protective agent. Furthermore, it is still more preferable to use in 0.01-0.3 mass%.

  The plate surface protective agent of the present invention is preferably pH 2-7 from the viewpoints of removability at the time of printing of the plate surface protective agent, safety during processing, storage stability, etc., but most preferably 2-5. .

  As post-processing after development of a lithographic printing plate, there are so-called washing water, an aqueous solution containing a surfactant and called a rinse solution, a method using an aqueous solution called a finisher or a protective gum solution containing gum arabic or starch derivatives and the like. is there. The plate surface protective agent of the present invention may be any of these post-treatment aqueous solutions.

  The post-treatment used in the present invention can be used in various combinations, for example, development → water washing → rinse solution treatment containing a surfactant, development → water washing → finish liquid treatment, etc. Therefore, it is preferable that the rinse liquid and the finisher liquid are less fatigued. Furthermore, a countercurrent multistage process using a rinse liquid or a finisher liquid is also a preferred embodiment.

  These post-processing are generally performed using an automatic developing machine including a developing unit and a post-processing unit. The post-treatment liquid is used by a method of spraying from a spray nozzle or a method of immersing and conveying in a treatment tank filled with the treatment liquid. In addition, a so-called disposable processing method in which treatment is performed with a substantially unused post-treatment liquid can also be applied.

  The lithographic printing plate obtained by such processing is loaded on an offset printing machine and used for printing a large number of sheets.

  In this invention, it is the most preferable aspect to contain the said phosphonic acid compound in a protective gum liquid.

[Protective gum solution]
The protective gum solution is an aqueous solution containing a hydrophilic polymer compound, and it is preferable to add an acid or a buffer to remove the alkaline component of the developer. Further, a surfactant, a chelating agent, a lubricant, a preservative, and a solubilizing agent are added. An agent or the like can be added.

  As the hydrophilic polymer, any hydrophilic polymer that can be conventionally used in a gum solution can be preferably used. For example, gum arabic, fiber derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose etc.) and modified products thereof, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, polyacrylamide and copolymers thereof, vinyl methyl ether / maleic anhydride copolymer Examples thereof include a polymer, a vinyl acetate / maleic anhydride copolymer, and a styrene / maleic anhydride copolymer.

  Surfactants that can be used include anionic surfactants and / or nonionic surfactants. For example, anionic surfactants 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, alkyl naphthalene sulfone. Acid salts, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, polyoxyethylene aryl ether sulfonates, polyoxyethylene naphthyl ether sulfonates, N-methyl-N-oleyl taurine sodium salts N-alkylsulfosuccinic acid monoamido disodium salts, petroleum sulfonates, nitrated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, Rualkyl nitrates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ethers Phosphate ester salts, polyoxyethylene alkylphenyl ether phosphate ester salts, partially saponified products of styrene-maleic anhydride copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalenesulfonate formalin condensates Etc. Among these, dialkyl sulfosuccinates, alkyl sulfate esters, and alkyl naphthalene sulfonates are particularly preferably used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene aryl ethers, polyoxyethylene naphthyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxy Propylene alkyl ether, glycerin fatty acid partial ester, sorbitan fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol mono fatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid moiety Esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylenated ester List oils, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, etc. It is done. Of these, polyoxyethylene alkylphenyl ethers, polyoxyethylene-polyoxypropylene block polymers and the like are preferably used.

  Fluorine-based and silicone-based anions and nonionic surfactants can also be used. Two or more of these surfactants can be used in combination. For example, two or more different from each other can be used in combination. For example, a combination of two or more different anionic surfactants or a combination of an anionic surfactant and a nonionic surfactant is preferable. Although the usage-amount of the said surfactant does not need to specifically limit, Preferably it is 0.01-20 mass% of a post-processing liquid.

  In addition to the above components, the protective gum solution may contain a polyhydric alcohol, an alcohol and an aliphatic hydrocarbon as necessary. Among the polyhydric alcohols, preferred specific examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, sorbitol and the like. Examples of the alcohol include propyl alcohol, butyl alcohol, and pen. Examples include alkyl alcohols such as tanol, hexanol, heptanol, and octanol, and alcohols having an aromatic ring such as pendyl alcohol, phenoxyethanol, and phenylaminoethyl alcohol.

  Examples of the aliphatic hydrocarbon include n-hexanol, methyl amyl alcohol, 2-ethylbutanol, n-heptanol, 3-heptanol, 2-octanol, 2-ethylhexanol, nonanol, 3,5,5-trimethylhexanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, heptadecanol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2,4 -Hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol and the like. The content of these lubricants is suitably 0.1 to 50% by mass, more preferably 0.5 to 3.0% by mass in the composition.

  The protective gum solution used in the present invention is generally advantageously used in the acidic range of pH 3-6. In order to adjust the pH to 3 to 6, it is generally adjusted by adding a mineral acid, an organic acid, an inorganic salt or the like to the protective gum solution. The addition amount is preferably 0.01 to 2% by mass. Examples of mineral acids include nitric acid, sulfuric acid, phosphoric acid, and metaphosphoric acid.

  Examples of the organic acid include citric acid, acetic acid, succinic acid, malonic acid, p-toluenesulfonic acid, tartaric acid, malic acid, lactic acid, levulinic acid, phytic acid, and organic phosphonic acid. Further, examples of the inorganic salt include magnesium nitrate, primary sodium phosphate, secondary sodium phosphate, nickel sulfate, sodium hexamethanoate, sodium tripolyphosphate, and the like. You may use together at least 1 sort (s) or 2 or more types, such as a mineral acid, an organic acid, or an inorganic salt.

  Antiseptic | preservative, an antifoamer, etc. can be added to the protective gum liquid used for this invention.

  For example, as a preservative, phenol or a derivative thereof, formalin, imidazole derivative, sodium dehydroacetate, 4-isothiazolin-3-one derivative, benzoisothiazolin-3-one, benztriazole derivative, amiding anidine derivative, quaternary ammonium salt, pyridine, Examples thereof include derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, and oxazine derivatives.

  A preferable addition amount is an amount that exerts a stable effect on bacteria, molds, yeasts, etc., and varies depending on the type of bacteria, molds, yeasts, but 0.01% with respect to the plate surface protective agent at the time of use. The range of ˜4% by mass is preferable, and it is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization. As the antifoaming agent, a silicon antifoaming agent is preferable. Among them, emulsification dispersion type and solubilization can be used. Preferably the range of 0.01-1.0 mass% is optimal with respect to the protection gum liquid at the time of use.

  Further, a chelate compound may be added. Preferred chelate compounds include, for example, ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, sodium salt thereof; ethylenediamine disuccinic acid, potassium salt thereof. Triethylenetetramine hexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid, potassium salt thereof, sodium salt thereof: nitrilotriacetic acid, sodium salt thereof; 1-hydroxyethane-1,1-diphosphone Acids, potassium salts, sodium salts; organic phosphonic acids or phosphonoalkanetricarboxylic acids such as aminotri (methylenephosphonic acid), potassium salts, sodium salts, etc. It can be mentioned. An organic amine salt is also effective in place of the sodium salt and potassium salt of the chelating agent. These chelating agents are selected so that they are stably present in the gum solution composition and do not impair the printability. The addition amount is suitably 0.001 to 1.0 mass% with respect to the gum solution at the time of use.

  In addition to the above components, a sensitizer can be added as necessary. For example, hydrocarbons such as turpentine oil, xylene, toluene, low heptane, solvent naphtha, kerosene, mineral spirit, petroleum fraction having a boiling point of about 120 ° C to about 250 ° C, such as dibutyl phthalate, dihebutyl phthalate, di-n-octyl Phthalic acid diester agents such as phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, dilauryl phthalate, butyl benzyl phthalate, such as dioctyl adipate, butyl glycol adipate, dioctyl azelate, dibutyl sebacate, di ( 2-ethylhexyl) aliphatic dibasic acid esters such as sebacate and dioctyl sebacate, epoxidized triglycerides such as epoxidized soybean oil, such as tricresyl phosphate, trioctylfolate Feto, phosphoric acid esters such as tris chloroethyl phosphate, for example, freezing point, such as benzoic acid esters of benzyl benzoate and at 15 ℃ below boiling point at one atmosphere include 300 ° C. or more plasticizers.

  In addition, caproic acid, enanthic acid, caprylic acid, helargonic acid, capric acid, undecyl acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoserine Saturated fatty acids such as acid, serotic acid, heptacosanoic acid, montanic acid, melicinic acid, lactelic acid, isovaleric acid, and acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, celetic acid, nillic acid, buteticidin Examples also include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, sardine acid, talylic acid and licanoic acid.

  More preferably, it is a fatty acid that is liquid at 50 ° C., more preferably 5 to 25 carbon atoms, and most preferably 8 to 21 carbon atoms. These sensitizers can be used alone or in combination of two or more. A preferable range for the amount used is 0.01 to 10% by mass of the gum, and a more preferable range is 0.05 to 5% by mass. The sensitizers as described above may be prepared by emulsifying and dispersing the gum as an oil phase, or may be solubilized with the help of a solubilizer.

In the present invention, the solid content concentration of the protective gum solution is preferably 5 to 30 g / l. The film thickness of the protective gum can be controlled by the conditions of the squeeze means of the self-machine. In the present invention, the coating amount of the protective gum is preferably 1 to 10 g / m ² from the viewpoint of processing stability and drying efficiency.

  In the present invention, the time from the end of application of the protective gum solution to the start of drying is preferably 3 seconds or less from the viewpoint of ink deposition. More preferably 2 seconds or less.

(Heating method)
In the present invention, it is treated with a plate surface protective agent and then heated at 50 to 200 ° C. “50 ° C. to 200 ° C.” means that the plate to be treated is 50 ° C. to 200 ° C. or is present in an atmosphere of 50 ° C. to 200 ° C.

  In the present invention, the effect of hydrophilization is particularly great when the heating temperature is in the range of 50 ° C to 200 ° C.

  The heating time is preferably 1 to 5 seconds. In the present invention, as a heating method, a known heating method such as a warm air heater or a far infrared heater can be used.

[Developer]
As the developer and the replenisher used for development in the processing method of the present invention, an alkaline solution containing silicic acid, phosphoric acid, carbonic acid, boric acid, phenols, saccharides, oximes, fluorinated alcohols and the like is used.

  An alkaline aqueous solution having a pH higher than 8.5 and lower than 13.0 is preferable. More preferably, the pH is 8.5-12. Among these, as weakly acidic substances such as phenols, saccharides, oximes and fluorinated alcohols, those having a dissociation index (pKa) of 10.0 to 13.2 are preferable. Such an acid is selected from those described in IONISATION CONSTANTS OF ORGANIC ACIDS IN AQUEOUS SOLUTION published by Pergamon Press, and specifically, salicylic acid (13.0), 3-hydroxy-2-naphthoate, and the like. Acid (12.84), catechol (12.6), gallic acid (12.4), sulfosalicylic acid (11.7), 3,4-dihydroxysulfonic acid (12.2), 3, 4-dihydroxybenzoic acid (11.94), 1,2,4-trihydroxybenzene (11.82), hydroquinone (11.56), pyrogallol (11.34), o-cresol (10) .33), resorsonol (11.27), p-cresol (10.2) ), M-cresol (phenol having a phenolic hydroxyl group, such as the 10.09) and the like.

  As the saccharide, a non-reducing sugar that is stable even in an alkali is preferably used. Such non-reducing sugars are saccharides that do not have a free aldehyde group or ketone group and do not exhibit reducing properties, and are trehalose-type oligosaccharides in which reducing groups are bonded to each other, and glycosides in which a reducing group of saccharides and non-saccharides are bonded. These are classified into sugar alcohols reduced by hydrogenation of the body and saccharides, both of which are preferably used in the present invention.

  Trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides include alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, durisit and allozulcit.

  Furthermore, maltitol obtained by hydrogenation of a disaccharide and a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide are preferably used. Furthermore, 2-butanone oxime (12.45), acetoxime (12.42), 1.2-cycloheptanedione oxime (12.3), 2-hydroxybenzaldehyde oxime (12.10), dimethyl Oximes such as glyoxime (11.9), ethanediamide dioxime (11.37) and acetophenone oxime (11.35) such as 2,2,3,3-tetrafluoropropanol-1 (12) .74), trifluoroethanol (12.37), trichloroethanol (12.24), and the like.

  In addition, aldehydes such as pyridine-2-aldehyde (12.68) and pyridine-4-aldehyde (12.05), adenosine (12.56), inosine (12.5), guanine ( 12.3), nucleic acid-related substances such as cytosine (12.2), hypoxanthine (12.1), xanthine (11.9), diethylaminomethylsulfonic acid (12.32), 1-amino-3,3,3-trifluorobenzoic acid (12.29), isopropylidenedisulfonic acid (12.10), 1,1-ethylidene diphosphonic acid (11.54), 1,1 Ethylidene disulfonic acid-1-hydroxy (11.52), benzimidazole (12.86), thiobenzamide (12.8), picoline thioamide (12.55), val Include the weak acid, such as vine acid (the same 12.5).

  These acidic substances may be used alone or in combination of two or more. Among these acidic substances, preferred are silicic acid, phosphoric acid, carbonic acid, sulfosalicylic acid, salicylic acid and sugar alcohols and saccharose of non-reducing sugars, especially silicic acid, D-sorbitol, saccharose, and reduced water candy in an appropriate pH range. It is preferable that it has a buffering action and is inexpensive.

  The proportion of these acidic substances in the developer is preferably from 0.1 to 30% by mass, and more preferably from 1 to 20% by mass.

  As the base to be combined with these acids, sodium hydroxide, ammonium, potassium and lithium are preferably used.

  These alkali agents are used alone or in combination of two or more.

  Other examples include potassium silicate, sodium silicate, lithium silicate, ammonium silicate, potassium metasilicate, sodium metasilicate, lithium metasilicate, ammonium metasilicate, tripotassium phosphate, trisodium phosphate, trilithium phosphate, triammonium phosphate, phosphoric acid. Dipotassium, disodium phosphate, dilithium phosphate, diammonium phosphate, potassium carbonate, sodium carbonate, lithium carbonate, ammonium carbonate, potassium bicarbonate, sodium bicarbonate, lithium bicarbonate, ammonium bicarbonate, potassium borate, sodium borate, boric acid Lithium, ammonium borate and the like can be mentioned and may be added in the form of a preformed salt.

  Again, sodium hydroxide, ammonium, potassium and lithium can be added to the pH adjustment. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used in combination.

The developer used in the present invention preferably contains no silicate, or has a silicate concentration of 0.1% by mass or less in terms of SiO ₂ concentration in terms of preventing sludge generation.

  The developer may contain various surfactants such as nonion, anion, cation and amphoteric.

  In addition, the effect of the present invention is greatly preferred when the development processing is carried out with a developer containing no silicate and containing a nonionic surfactant.

  In the present invention, even if the developer does not contain silicate, the degree of hydrophilization is greater than that of the conventional plate surface protective solution, and the effect of preventing stains is great.

  Examples of the nonionic surfactant include 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 mono fatty 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, fat Acid diethanol amides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, anionic surfactants such as trialkylamine oxides. Of the surfactants listed above, those having polyoxyethylene can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene, polyoxybutylene, and these surfactants are also included. The

  Examples of anionic, cationic, and amphoteric surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid ester salts, linear alkyl benzene sulfonic acid salts, branched chain alkyl benzenes Sulfonates, alkylnaphthalenesulfonates, alkylphenoxypolyoxyethylenepropylsulfonates, polyoxyethylenealkylsulfophenylether salts, N-methyl-N-oleyl taurine sodium salt, N-alkylsulfosuccinic acid monoamide disodium salts , Petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate esters, alkyl sulfate esters, polyoxyethylene alkyl ether sulfate ester Salts, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styrylphenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ether phosphate esters, polyoxyethylene alkylphenyl Anionic surfactants such as ether phosphate ester salts, saponified saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, naphthalene sulfonate formalin condensates, Cationic surfactants such as alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, carboxybetaines, aminocarboxylic acids, sulfo Betaines, amino acid esters, amphoteric surfactants such as imidazolines, and the like, which may be used combination of a plurality of ones.

  The addition amount of the surfactant is preferably 0.2 to 30% by mass, more preferably 0.3 to 15% by mass with respect to the developer composition.

As described above, the developer does not contain silicate as an alkali, or the concentration of silicate is preferably 0.1% by mass or less in terms of SiO ₂ concentration, but further has an oxyalkylene group. A developer containing a surfactant is preferred in order to exhibit the effects of the present invention.

  The surfactant having the oxyalkylene group is preferably the following compound A, compound B or compound C.

  Compound A: An anionic surfactant containing a polyoxyethylene group in which the molecular weight of the saturated alkyl group in the hydrophobic group portion is 25% or less of the molecular weight of the entire hydrophobic group.

Compound _{B: R 1 -O- (C 3} H 6 O) m - (C 2 H 4 O) n -H
[Wherein, R ₁ represents an alkyl group which may have a substituent or an aryl group which may have a substituent, m represents an integer of 1 to 3, and n represents an integer of 2 to 30. . ]
Compound C: A nonionic surfactant containing a polyoxyethylene group in which the molecular weight of the saturated alkyl group in the hydrophobic group portion is 25% or less of the molecular weight of the entire hydrophobic group.

  Specific examples of these are shown below.

  The developing solution in the present invention is not only an unused solution used at the start of development, but also a replenishing solution is replenished in order to correct the activity of the solution that decreases due to the processing of the PS plate. Contains retained liquid (so-called running liquid). The replenisher therefore needs to have a higher activity (alkali concentration) than the developer, so the pH of the replenisher may exceed 13.0.

  Various surfactants, organic solvents, development stabilizers, reducing agents, and the like can be added to the developer and replenisher as necessary.

(Photopolymerization initiator)
The photopolymerization initiator used in the photosensitive layer of the photosensitive lithographic printing plate according to the present invention is a compound capable of initiating polymerization of a polymerizable ethylenic double bond-containing compound in the photosensitive layer by image exposure. Examples thereof include bromine compounds having a structure represented by the formula (1) or (2), titanocene compounds, monoalkyltriaryl borate compounds, iron arene complex compounds, and the like.

Formula _{(1) R 2 -CBr 2 -} (C = O) -R 3
In the formula, R ₂ represents a hydrogen atom, a bromine atom, an alkyl group, an aryl group, an acyl group, an alkylsulfonyl group, an arylsulfonyl group, or a cyano group. R ₃ represents a monovalent substituent. R ₂ and R ₃ may be bonded to form a ring.

Formula (2) CBr ₃ — (C═O) —X—R ₄
R ₄ represents a monovalent substituent. X represents —O— or —NR ₅ —. R ₅ represents a hydrogen atom or an alkyl group. R ₄ and R ₅ may be bonded to form a ring.

  Examples of the titanocene compound include compounds described in JP-A-63-41483 and JP-A-2-291. More preferred specific examples include bis (cyclopentadienyl) -Ti-di-chloride. , Bis (cyclopentadienyl) -Ti-bis-phenyl, bis (cyclopentadienyl) -Ti-bis-2,3,4,5,6-pentafluorophenyl, bis (cyclopentadienyl) -Ti -Bis-2,3,5,6-tetrafluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4,6-trifluorophenyl, bis (cyclopentadienyl) -Ti-bis-2 , 6-difluorophenyl, bis (cyclopentadienyl) -Ti-bis-2,4-difluorophenyl, bis (methylcyclopentadienyl) -Ti-bi -2,3,4,5,6-pentafluorophenyl, bis (methylcyclopentadienyl) -Ti-bis-2,3,5,6-tetrafluorophenyl, bis (methylcyclopentadienyl) -Ti -Bis-2,6-difluorophenyl (IRUGACURE 727L: manufactured by Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,6-difluoro-3- (py-1-yl) phenyl) titanium (IRUGACURE784) : Ciba Specialty Chemicals), bis (cyclopentadienyl) -bis (2,4,6-trifluoro-3- (pyridin-1-yl) phenyl) titanium bis (cyclopentadienyl) -bis ( 2,4,6-trifluoro-3- (2-5-dimethylpy-1-yl) phenyl) titanium And the like.

  Examples of the monoalkyltriaryl borate compound include compounds described in JP-A-62-154024 and JP-A-62-143044. More preferred specific examples include tetra-n-butylammonium n-butyl. -Trinaphthalen-1-yl-borate, tetra-n-butylammonium n-butyl-triphenyl-borate, tetra-n-butylammonium n-butyl-tri- (4-tert-butylphenyl) -borate, tetra-n- Examples include butylammonium n-hexyl-tri- (3-chloro-4-methylphenyl) -borate and tetra-n-butylammonium n-hexyl-tri- (3-fluorophenyl) -borate.

  Examples of the iron arene complex compound include compounds described in JP-A-59-219307, and more preferable specific examples include η-benzene- (η-cyclopentadienyl) iron hexafluorophosphate, η- Cumene- (η-cyclopentadienyl) iron hexafluorophosphate, η-fluorene- (η-cyclopentadienyl) iron hexafluorophosphate, η-naphthalene- (η-cyclopentadienyl) iron hexafluorophosphate, η -Xylene- (η-cyclopentadienyl) iron hexafluorophosphate, η-benzene- (η-cyclopentadienyl) iron tetrafluoroborate and the like.

  In addition, any photopolymerization initiator can be used in combination. For example, J. et al. Carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo, diazo compounds, halogen compounds, and photoreductive dyes as described in Chapter 5 of “Light Sensitive Systems” by J. Kosar Etc. More specific compounds are disclosed in British Patent 1,459,563.

  That is, the following can be used as a photopolymerization initiator that can be used in combination.

  Benzoin derivatives such as benzoin methyl ether, benzoin-i-propyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4′-bis (dimethyl) Benzophenone derivatives such as amino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-i-propylthioxanthone; anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; N-methylacridone, N-butylacridone and the like In addition to α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone and uranyl compounds, JP-B-59-1281, 61-9621 and JP-A-60-60104 Triazine derivatives; organic peroxides described in JP-A-59-1504 and JP-A-61-243807; JP-B-43-23684, JP-A-44-6413, JP-A-44-6413, JP-A-47-1604, and US patents Diazonium compounds described in US Pat. No. 3,567,453; organic azide compounds described in US Pat. Nos. 2,848,328 and 2,852,379 and 2,940,853; O-quinonediazides described in JP-A Nos. 13109, 38-18015 and 45-9610; JP-B-55-39162, JP-A-59-14023 and “Macromolecules”, Vol. 10, 1307 Various onium compounds described on page 1977; azo compounds described in JP-A-59-142205 Compound: JP-A-1-54440, European Patents 109,851, 126,712 and “Journal of Imaging Science (J. Imag. Sci.)”, Vol. 30, 174 (1986) (Oxo) sulfonium organoboron complexes described in Japanese Patent Application Nos. 4-56831 and 4-89535; "Coordination Chemistry Review", 84, 85-277 (1988) ) And transition metal complexes containing a transition metal such as ruthenium described in JP-A-2-182701; 2,4,5-triarylimidazole dimer described in JP-A-3-209477; carbon tetrabromide, JP Organic halogen compounds described in JP-A-59-107344, etc. And the like.

  When laser light is used as the light source, a sensitizing dye is preferably added to the photosensitive layer. It is preferable to use a dye having an absorption maximum wavelength in the vicinity of the wavelength of the light source.

  Examples of compounds for wavelength sensitization from visible light to near infrared include cyanine, phthalocyanine, merocyanine, porphyrin, spiro compound, ferrocene, fluorene, fulgide, imidazole, perylene, phenazine, phenothiazine, polyene, azo compound, diphenylmethane, triphenyl Ketone alcohol borate complexes such as methane, polymethine acridine, coumarin, coumarin derivatives, ketocoumarin, quinacridone, indigo, styryl, pyrylium compounds, pyromethene compounds, pyrazolotriazole compounds, benzothiazole compounds, barbituric acid derivatives, thiobarbituric acid derivatives, etc. Further, European Patent No. 568,993, U.S. Pat. Nos. 4,508,811, 5,227,227, JP-A-2001-125255, JP-A-11- Compounds described in such Patent 71,969 are also used.

  Specific examples of the combination of the photopolymerization initiator and the sensitizing dye include combinations described in JP-A Nos. 2001-125255 and 11-271969.

  Although the compounding quantity of these photoinitiators is not specifically limited, Preferably, it is 0.1-20 mass parts with respect to 100 mass parts of compounds which can be addition-polymerized or bridge | crosslinked. The mixing ratio of the photopolymerization initiator and the sensitizing dye is preferably in the range of 1: 100 to 100: 1 in terms of molar ratio.

(Polymerizable ethylenic double bond-containing compound)
The polymerizable ethylenic double bond-containing compound according to the present invention is a compound that can be polymerized by image exposure, and is a radically polymerizable monomer, an ethylenic double bond that can be polymerized in a molecule used in an ultraviolet curable resin. Polyfunctional monomers having a plurality of bonds and polyfunctional oligomers can be used.

  The compound is not limited, but preferred examples include 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glycerol acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, tetrahydro Furfuryloxyhexanolide acrylate, acrylate of ε-caprolactone adduct of 1,3-dioxane alcohol, monofunctional acrylic acid esters such as 1,3-dioxolane acrylate, or these acrylates as methacrylate, itaconate, crotonate, maleate Methacrylic acid, itaconic acid, crotonic acid, maleic acid esters such as ethylene glycol diacrylate , Triethylene glycol diacrylate, pentaerythritol diacrylate, hydroquinone diacrylate, resorcin diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, dipentylate of hydroxypentylate neopentyl glycol, Diacrylate of neopentyl glycol adipate, Diacrylate of ε-caprolactone adduct of neopentyl glycol hydroxypivalate, 2- (2-hydroxy-1,1-dimethylethyl) -5-hydroxymethyl-5-ethyl-1, Ε-caprolactone adduct of 3-dioxane diacrylate, tricyclodecane dimethylol acrylate, tricyclodecane dimethylol acrylate Difunctional acrylic acid esters such as diglycidyl ether diacrylate of 1,6-hexanediol, or methacrylic acid, itaconic acid, crotonic acid, maleic acid ester in which these acrylates are replaced with methacrylate, itaconate, crotonate, maleate, For example, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dipentaerythritol Ε-caprolactone adduct of hexaacrylate, pyrogallol triacrylate Polyfunctional acrylic acid esters such as propionic acid / dipentaerythritol triacrylate, propionic acid / dipentaerythritol tetraacrylate, hydroxypivalylaldehyde-modified dimethylolpropane triacrylate, or these acrylates with methacrylate, itaconate, crotonate, Examples thereof include methacrylic acid, itaconic acid, crotonic acid, and maleic acid ester instead of maleate.

  Prepolymers can also be used as described above. Examples of the prepolymer include compounds as described below, and a prepolymer obtained by introducing acrylic acid or methacrylic acid into an oligomer having an appropriate molecular weight and imparting photopolymerizability can be preferably used.

  These prepolymers may be used alone or in combination of two or more, and may be used by mixing with the above-mentioned monomers and / or oligomers.

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

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

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

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

  In the present invention, it is preferable to use an addition-polymerizable ethylenic double bond-containing monomer containing a tertiary amino group in the molecule. Although there is no particular limitation on the structure, a tertiary amine compound having a hydroxyl group modified with glycidyl methacrylate, methacrylic acid chloride, acrylic acid chloride or the like is preferably used. Specifically, polymerizable compounds described in JP-A-1-165613, 1-203413, and 1-197213 are preferably used.

  Furthermore, in the present invention, a reaction product of a polyhydric alcohol containing a tertiary amino group in the molecule, a diisocyanate compound, and a compound containing an ethylenic double bond capable of addition polymerization with a hydroxyl group in the molecule is used. It is preferable.

  Examples of the polyhydric alcohol containing a tertiary amino group in the molecule include triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, Nn-butyldiethanolamine, N-tert-butyldiethanolamine, N, N-di (hydroxyethyl) aniline, N, N, N ′, N′-tetra-2-hydroxypropylethylenediamine, p-tolyldiethanolamine, N, N, N ′, N′-tetra-2-hydroxyethylethylenediamine, N, N-bis (2-hydroxypropyl) aniline, allyldiethanolamine, 3- (dimethylamino) -1,2-propanediol, 3-diethylamino-1,2-propanediol, N, N-di (n-propyl) Amino-2,3-propanediol, N, N-di iso- propyl) amino-2,3-propanediol, 3- (N-methyl--N- benzylamino) -1,2-propane diol, and the like, but is not limited thereto.

  Examples of the diisocyanate compound include butane-1,4-diisocyanate, hexane-1,6-diisocyanate, 2-methylpentane-1,5-diisocyanate, octane-1,8-diisocyanate, 1,3-diisocyanate methyl-cyclohexanone. 2,2,4-trimethylhexane-1,6-diisocyanate, isophorone diisocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene- Examples include 2,5-diisocyanate, tolylene-2,6-diisocyanate, 1,3-di (isocyanatomethyl) benzene, 1,3-bis (1-isocyanato-1-methylethyl) benzene, and the like. Limited to Not. Examples of the compound containing an ethylenic double bond capable of addition polymerization with a hydroxyl group in the molecule include compounds such as MH-1 to MH-13, but are not limited thereto. Preferable examples include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxypropylene-1,3-dimethacrylate, 2-hydroxypropylene-1-methacrylate-3-acrylate, and the like.

  These reactions can be carried out in the same manner as a method for synthesizing urethane acrylate by a reaction of a normal diol compound, diisocyanate compound, and hydroxyl group-containing acrylate compound.

Specific examples of reaction products of polyhydric alcohols containing a tertiary amino group in the molecule, diisocyanate compounds, and compounds containing an ethylenic double bond capable of addition polymerization with a hydroxyl group in the molecule are shown below. .
M-1: reaction product of triethanolamine (1 mol), hexane-1,6-diisocyanate (3 mol), 2-hydroxyethyl methacrylate (3 mol) M-2: triethanolamine (1 mol), isophorone Reaction product of diisocyanate (3 mol) and 2-hydroxyethyl acrylate (3 mol) M-3: Nn-butyldiethanolamine (1 mol), 1,3-bis (1-isocyanate-1-methylethyl) Reaction product of benzene (2 mol), 2-hydroxypropylene-1-methacrylate-3-acrylate (2 mol) M-4: Nn-butyldiethanolamine (1 mol), 1,3-di (isocyanatomethyl) ) Reaction of benzene (2 mol), 2-hydroxypropylene-1-methacrylate-3-acrylate (2 mol) Product M-5: Reaction product of N-methyldiethanolamine (1 mol), tolylene-2,4-diisocyanate (2 mol), 2-hydroxypropylene-1,3-dimethacrylate (2 mol) An acrylate or an alkyl acrylate described in JP-A-1-105238 and JP-A-2-127404 can be used.

(Polymer binder)
The polymer binder in the present invention can hold each component in the polymerization type photosensitive layer in the photosensitive layer, and is an acrylic polymer, polyvinyl butyral resin, polyurethane resin, polyamide resin, polyester resin, epoxy resin, Phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, shellac, and other natural resins can be used. Two or more of these may be used in combination.

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

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

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

  Furthermore, the monomer etc. as described in following 1) -14) can be used for a polymer binder as another copolymerization monomer.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  Specific examples of the compound containing both an unsaturated bond and an epoxy group in the molecule include glycidyl acrylate, glycidyl methacrylate, and an epoxy group-containing unsaturated compound described in JP-A No. 11-271969.

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

  Further, the acid value of the polymer binder is preferably in the range of 10 to 150, more preferably in the range of 30 to 120, and the use in the range of 50 to 90 balances the polarity of the entire photosensitive layer. From the viewpoint of taking, it is particularly preferable, and this can prevent aggregation of the pigment in the photosensitive layer coating solution.

  The polymerization type photosensitive layer of the present invention may have an oxygen blocking layer thereon. For the oxygen barrier layer, a water-soluble polymer capable of forming a film having low oxygen permeability is used. Specifically, it contains polyvinyl alcohol and polyvinyl pyrrolidone. Polyvinyl alcohol has an effect of suppressing permeation of oxygen, and polyvinyl pyrrolidone has an effect of ensuring adhesion with an adjacent photosensitive layer.

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

(Aluminum plate support)
The aluminum plate support used in the present invention is an aluminum plate or an aluminum alloy plate.

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

  The aluminum plate support that can be used in the photosensitive lithographic printing plate of the present invention and the processing method of the present invention is subjected to a degreasing treatment to remove the rolling oil on the surface prior to roughening (graining treatment). It is preferable. As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is generated on the surface of the support. It is preferable to perform the treatment.

  Examples of the roughening method include a mechanical method and a method of etching by electrolysis.

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

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

The electrochemical surface roughening method is not particularly limited, but a method of electrochemical surface roughening in an acidic electrolyte is preferable. As the acidic electrolytic solution, an acidic electrolytic solution usually used in an electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolytic solution is preferably used. As the electrochemical surface roughening method, for example, methods described in Japanese Patent Publication No. 48-28123, British Patent No. 896,563 and Japanese Patent Laid-Open No. 53-67507 can be used. This roughening method can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000c / dm ^2. The temperature at which the roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C.

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

When a hydrochloric acid-based electrolyte is used as the electrolyte, it can be generally applied by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 2 to 30 volts. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably 100~2000c / dm ^2, and more and more preferably selected from the range of 200~1000c / dm ^2. The temperature at which the electrochemical roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of hydrochloric acid in the electrolytic solution is preferably 0.1 to 5% by mass. If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

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

  The mechanical surface roughening method and the electrochemical surface roughening method may each be used alone for roughening, or the mechanical surface roughening treatment method followed by the electrochemical surface roughening method may be used for roughening. You may face it.

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

  The anodized support may be sealed as necessary. These sealing treatments can be carried out using known methods such as hot water treatment, boiling water treatment, steam treatment, alkali metal silicate or sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, ammonium acetate treatment, etc. it can.

  Furthermore, after performing these treatments, a treatment for coating the support surface with polyvinylphosphonic acid can be performed. The coating treatment is not limited to a coating method, a spray method, a dip method, or the like, but a dip method is suitable for making the equipment inexpensive. In the case of a dip type, it is preferable to treat polyvinylphosphonic acid with a 0.05 to 3% aqueous solution. The treatment temperature is preferably 20 to 90 ° C., and the treatment time is preferably 10 to 180 seconds.

After the treatment, it is preferable to perform a squeegee treatment or a water washing treatment in order to remove the excessively laminated polyvinylphosphonic acid. Furthermore, it is preferable to perform a drying process. As a drying temperature, 20-95 degreeC is preferable. Coverage of polyvinylphosphonic acid of the aluminum support surface of the present invention is preferably from 3 to 15 mg / m ^2, further 3.5~10mg / m ² is preferred. Various combinations of polyvinyl phosphonic acid aqueous solution concentration, treatment temperature, and treatment time can be used to obtain a desired coating amount.

(exposure)
Examples of the light source for exposure of the photosensitive lithographic printing plate in the present invention include a laser, a light emitting diode, a xenon lamp, a xenon flash lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a tungsten lamp, a high-pressure mercury lamp, and an electrodeless light source. Can be mentioned.

  In the case of batch exposure, a mask material in which a negative pattern of a desired exposure image is formed with a light-shielding material may be superimposed on the photopolymerization type photosensitive layer and exposed.

  When using an array-type light source such as a light-emitting diode array, or when controlling exposure of a light source such as a halogen lamp, metal halide lamp, or tungsten lamp with an optical shutter material such as liquid crystal or PLZT, digital Exposure is possible and preferable. In this case, direct writing can be performed without using a mask material.

  Laser exposure is suitable for direct writing without using a mask material because light exposure can be performed in the form of a beam according to image data. When a laser is used as a light source, it is easy to reduce the exposure area to a very small size, and high-resolution image formation is possible.

(Preparation of photosensitive lithographic printing plate material 1)
Although a synthesis example, a support body preparation example, and an example are specifically shown below, embodiments of the present invention are not limited thereto. In the examples, “parts” represents “parts by mass” unless otherwise specified.

(Binder synthesis)
(Synthesis of acrylic copolymer 1)
In a three-necked flask under a nitrogen stream, 30 parts of methacrylic acid, 50 parts of methyl methacrylate, 20 parts of ethyl methacrylate, 500 parts of isopropyl alcohol and 3 parts of α, α'-azobisisobutyronitrile are placed in a nitrogen stream. The mixture was reacted for 6 hours in an oil bath at 0 ° C. Then, after refluxing at the boiling point of isopropyl alcohol for 1 hour, 3 parts of triethylammonium chloride and 25 parts of glycidyl methacrylate were added and reacted for 3 hours to obtain an acrylic copolymer 1. The weight average molecular weight measured using GPC was about 35,000, and the glass transition temperature (Tg) measured using DSC (differential thermal analysis) was about 85 ° C.

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

(Preparation of lithographic printing plate material) On the support, a photopolymerizable photosensitive layer coating solution 1 having the following composition was applied with a wire bar so as to be 1.5 g / m ² at the time of drying. It dried for minutes and obtained the photopolymerization photosensitive layer application | coating sample.

(Photopolymerizable photosensitive layer coating solution 1)
Addition-polymerizable ethylenic double bond-containing monomer: M-3 (above) 25.0 parts Addition-polymerizable ethylenic double bond-containing monomer: NK ester 4G
(Polyethylene glycol dimethacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.) 25.0 parts Polymerization initiator T-1 2.0 parts Polymerization initiator T-2 2.0 parts Polymerization initiator BR22 1.0 part Polymerization initiator BR43 1.0 Parts Spectral sensitizing dye D-1 1.5 parts Spectral sensitizing dye D-2 1.5 parts Acrylic copolymer 1 40.0 parts N-phenylglycine benzyl ester 4.0 parts Phthalocyanine pigment (MHI454: Gokoku dye) 6.0 parts 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (Sumilyzer GS: manufactured by Sumitomo 3M) 0.5 parts Fluorosurfactant (F-178K; manufactured by Dainippon Ink & Co., Ltd.) 0.5 part Methyl ethyl ketone 80 parts Cyclohexanone 820 parts Photosensitive lithographic printing plate having tomographic coating solution 1 coated with an applicator so as to have a dry weight of 1.8 g / m ² , dried at 75 ° C. for 1.5 minutes, and having an oxygen blocking layer on the photosensitive layer Material 1 was produced.

(Oxygen barrier layer coating solution 1)
Polyvinyl alcohol (GL-05: Nippon Synthetic Chemical Co., Ltd.) 89 parts Water-soluble polyamide (P-70: Toray Industries, Inc.) 10 parts Surfactant (Surfinol 465: Nissin Chemical Industry Co., Ltd.) 0.5 parts Water 900 (Production of photosensitive lithographic printing plate material 2)
A photosensitive lithographic printing plate material 2 was prepared in the same manner as described above except that the photopolymerizable photosensitive layer coating solution 1 was changed to the following photopolymerizable photosensitive layer coating solution 2.

(Photopolymerizable photosensitive layer coating solution 2)
Addition-polymerizable ethylenic double bond-containing monomer: M-3 (above) 25.0 parts Addition-polymerizable ethylenic double bond-containing monomer: NK ester 4G
(Polyethylene glycol dimethacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.) 25.0 parts Polymerization initiator T-3 4.0 parts Polymerization initiator BR22 1.0 part Polymerization initiator BR43 1.0 part Spectral sensitizing dye D-3 0 parts Acrylic copolymer 1 40.0 parts N-phenylglycine benzyl ester 4.0 parts Phthalocyanine pigment (MHI454: manufactured by Gokoku Dye Co., Ltd.) 6.0 parts 2-t-butyl-6- (3-t-butyl -2-Hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (Sumilyzer GS: manufactured by Sumitomo 3M) 0.5 part Fluorosurfactant (F-178K; manufactured by Dainippon Ink & Co.) 0.5 part Methyl ethyl ketone 80 parts Cyclohexanone 820 parts (Preparation of photosensitive lithographic printing plate material 3)
The photosensitive lithographic printing plate was prepared in the same manner as the photosensitive lithographic printing plate material 1 except that the spectral sensitizing dye of the photopolymerizable photosensitive layer coating solution 1 was changed to D-5 and D-7. Material 3 was produced.

(Developer example formulation)
(Developers / developer replenishers used in Example 1 are as follows)
《Developer formulation》
Potassium carbonate 2.5g / L
Potassium bicarbonate 5.0g / L
Surfactant A 50.0 g / L
Ethylenediaminetetraacetic acid 0.5g / L
Potassium hydroxide The following pH level The remaining component is water. pH: 11.4
<Development replenisher formulation>
Potassium carbonate 2.5g / L
Potassium bicarbonate 5.0g / L
Surfactant A 50.0 g / L
Ethylenediaminetetraacetic acid 0.5g / L
Potassium hydroxide The following pH level The remaining component is water. pH: 12.4
(Developers / developer replenishers used in Examples 2, 3, 5 and Comparative Examples 1-5)
The surfactant / developer replenisher surfactant A in Example 1 was changed to the surfactant in Table 1.

(Developer / developer replenisher used in Example 4 is as follows)
<< Developer Formula 2 >>
Potassium silicate aqueous solution (SiO ₂ 26 mass%, K ₂ O 13.5 mass%) 40.0 g / L
Ethylenediaminetetraacetic acid 0.5g / L
Surfactant A 40.0 g / L
Potassium hydroxide The following pH level The remaining component is water. pH: 12.3
<Development replenisher formulation 2>
Potassium silicate aqueous solution (SiO ₂ 26 mass%, K ₂ O 13.5 mass%) 40.0 g / L
Ethylenediaminetetraacetic acid 0.5g / L
Surfactant A 40.0 g / L
Potassium hydroxide The following pH level The remaining component is water. pH: 12.7
(Gum solution (finisher solution) formulation)
<< Plate surface protector Example 1 (1L aqueous solution formulation) >>
White dextrin 5.0% by mass
Hydroxypropyl etherified starch 10.0% by mass
1st Ammon Phosphate 0.1% by mass
Sodium dilauryl succinate 0.15% by mass
Polyoxyethylene naphthyl ether 0.5% by mass
Sodium dodecylbenzenesulfonate 0.3% by mass
Ethylene glycol 1.0% by mass
Ethylenediaminetetraacetic acid disodium 0.05 mass%
Ethylparaben 0.05% by mass
Phosphonic acid compound A 0.5% by mass
Phosphonic acid compound D 0.5% by mass
About Examples 2-4 and Comparative Examples 1-5, what changed the phosphonic acid compound into the compound of Table 1 was used.

(Examples 1-5, Comparative Examples 1-5)
Examples 1-5 and Comparative Examples 1-5 were implemented using the said photosensitive lithographic printing plate materials 1, 2, and 3 as shown in Table 1.

  When photosensitive planographic printing plate materials 1 and 2 are used, 2400 dpi (dpi represents the number of dots per 2.54 cm) using a CTP exposure apparatus (Tigercat: manufactured by ECRM) equipped with an FD-YAG laser light source Image exposure (exposure pattern used 100% image area, 175 LPI, 50% square dots).

  When the photosensitive printing plate material 3 was used, the same image exposure was performed using a plate setter (Tiger Cat: a modified product manufactured by ECRM) provided with a light source having a laser of 408 nm and 30 mW output.

Next, it is equipped with a pre-rinsing part for removing the oxygen blocking layer before development, a developing part filled with a developer having the following composition, a washing part for removing the developer adhering to the plate surface, and the above-mentioned gum solution for protecting the image area. Development was carried out at 400 m ² using a CTP automatic developing machine (PHW32-U: manufactured by Technology) such that the area ratio of the image area to the non-image area was 2: 8. The developer was replenished to about 60 ml / m ² .

(Stop dirt)
The printing plate obtained by developing the plate after processing 400 m ² with an automatic processor is applied to a printing machine (DAIYA, 1F-1 manufactured by Mitsubishi Heavy Industries, Ltd.), coated paper, dampening water (etched by Tokyo Ink Co., Ltd.) Liquid SG-51, density 1.5%), ink (VOC zero ink “TK Hi-Echo SOY1” manufactured by Toyo Ink Co., Ltd.) was used for printing, and when 5,000 printing plates used for this printing were printed, The printing machine was once stopped and left for 1 hour, and then printing was restarted. After printing 100 sheets, fine dot-like stains generated on the printed matter were evaluated by the number within 100 cm ² . 20 or less is a good range.

  The results are shown in Table 1. It can be seen from Table 1 that the processing method of the present invention improves the occurrence of smudges after resuming printing.

Claims (5)

After exposing and developing a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing a polymerizable ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support (A) A lithographic printing process comprising treating with a plate surface protective agent comprising a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more, and then heating at 50 to 200 ° C. Plate processing method. 2. The method for processing a photosensitive lithographic printing plate according to claim 1, wherein the (B) phosphonic acid compound having a molecular weight of 2000 or more is a polyvinyl phosphonic acid compound. 2. The method for processing a photosensitive lithographic printing plate according to claim 1, wherein the (B) phosphonic acid compound having a molecular weight of 2000 or more is a phosphonic acid-modified starch. The developer used for the development processing is a developer containing a surfactant having an oxyalkylene group and having a silicate content of 0 to 0.1% (SiO ₂ mass conversion). The processing method of the photosensitive lithographic printing plate of Claim 1 thru | or 3. After exposing and developing a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer containing a polymerizable ethylenic double bond-containing compound, a photopolymerization initiator, and a polymer binder on an aluminum plate support A plate surface protecting agent for a photosensitive lithographic printing plate, comprising: (A) a phosphonic acid compound having a molecular weight of less than 2000 and (B) a phosphonic acid compound having a molecular weight of 2000 or more.