JP3376912B2 - Processing method of photosensitive lithographic printing plate - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for processing a photosensitive lithographic printing plate which is exposed by a laser.

[0002]

2. Description of the Related Art In recent years, a plate-making system (CTP system) which directly outputs edited digital data input to a computer onto a photosensitive lithographic printing plate by a laser scanning line has come to a stage of practical use. By omitting the intermediate process by this system, it became possible to greatly rationalize the plate making process. As the plate material used here, a photopolymer-based plate material using a photopolymerizable photosensitive material is advantageous in view of easiness of handling, waste liquid, and the like. However, since the photopolymer-based photosensitive material has poor adhesion to the support,
Depending on the plate making and printing conditions, there was a problem that the printing durability was extremely poor. In order to avoid this, as a part of the treatment process, a heat treatment step at about 100 ° C. after laser exposure is often incorporated. However, this process requires the equipment to be at a high temperature, making it difficult to perform unattended operation at night, etc., and it is necessary to have an operator even after the treatment is complete until the equipment is cooled down. Therefore, this is one of the purposes of the CTP system. It goes against the rationalization. On the other hand, it is also known that the photopolymer plate material is exposed and developed and then post-exposed.

[0003]

However, according to the study by the present inventors, even when post-exposure is performed, printing durability and developing property (staining property) before and after storage depend on the type of plate material and the type of developing solution. Turned out to be inadequate. That is, the present invention is a photopolymer-type photosensitive lithographic printing plate, a processing method for providing a printing plate having stable printing durability before and after storage and other excellent printing performance without heating after exposure. To provide.

[0004]

As a result of intensive studies, the present inventor has found that the above problems can be solved by exposing a photosensitive lithographic printing plate under specific conditions to laser exposure and development, and then exposing the entire surface. I found it. That is, the gist of the present invention is to provide a photopolymerizable photosensitive layer having a film thickness of 1.2 to 4 g / m ² and a film thickness of 2 to 8 on a support having a center line average roughness (Ra) of 0.35 μm or more.
A photosensitive lithographic printing plate comprising a protective layer of g / m ² sequentially laminated, after laser exposure, developed with a developer containing an alkali metal silicate, and then exposed over the entire surface. It lies in the method of processing the printing plate.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The photosensitive lithographic printing plate used in the processing method of the present invention comprises a support having a hydrophilic surface and a photopolymerizable photosensitive photosensitive layer and a protective layer as an oxygen barrier layer, which are sequentially laminated.

As the support, metal, plastic, paper or the like is used, but an aluminum support is particularly preferably used. When an aluminum plate is used as the support, surface treatment such as graining treatment, anodic oxidation treatment and, if necessary, pore sealing treatment is performed. A known method can be applied to these treatments.

Examples of the graining method include a mechanical method and an electrolytic etching method. Examples of mechanical methods include a ball polishing method, a brush polishing method, a liquid homing polishing method, and a buff polishing method. Electrolytic etching is generally performed in acidic electrolyte. As the electrolytic solution, one mainly containing hydrochloric acid or nitric acid is preferable, and chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, etc. may be added to the electrolytic solution if necessary. You can also

The conditions of electrolytic etching are selected depending on the kind of electrolytic solution, but normally applied voltage is 1 to 50 V,
Preferably 5 to 40 V, current density is 10 to 200 A / d
m ² , preferably 20 to 150 A / dm ² , and the current used can be either alternating current or direct current, but alternating current is more preferred. The frequency of the alternating current is 1
To 400 Hz, preferably 20 to 100 Hz, and the electrolyte temperature is 10 to 50 ° C., preferably 15 to 40.
℃.

The above-mentioned various graining methods can be used alone or in combination depending on the composition of the aluminum material and the like.
The centerline average roughness (Ra) according to the standard must be 0.35 μm or more. When Ra is smaller than this, it is difficult to secure sufficient printing durability. The upper limit of Ra is usually 1.0 μm or less. In the case of electrolytic etching, the temperature, time, voltage, current density, electrolytic solution type, concentration, etc. are adjusted appropriately to obtain Ra.
Can be within the above range. The electrolytically roughened aluminum support is optionally desmutted. The desmutting treatment uses an acid or alkali aqueous solution. Examples of the above acid include sulfuric acid, nitric acid,
Hydrochloric acid, phosphoric acid, chromic acid, etc. are included, and examples of the alkali include sodium hydroxide, potassium hydroxide, potassium tertiary phosphate, sodium aluminate, sodium metasilicate, etc. Among them, alkali is used. Preferably. The treatment method may be any method such as a method of immersing in the above aqueous solution of acid or alkali, or a spray method. When the above is carried out in an aqueous solution of alkali, since the etching treatment agent and impurities such as dissolved smut remain on the aluminum surface, sulfuric acid, nitric acid, hydrochloric acid,
It is preferable to perform neutralization treatment with an acid such as phosphoric acid or chromic acid, or a mixed acid thereof. The treatment method may be any method such as dipping or spraying.

The anodizing treatment is carried out by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution and electrolyzing with an aluminum plate as an anode. Since the anodizing condition varies depending on the type of electrolyte used, it cannot be generally stated. For example, an aqueous solution of 1 to 50% by weight of sulfuric acid and / or phosphoric acid or the like is used as the electrolyte, and the electrolyte temperature is 5 to 70 ° C. Current density 1-20
A / dm ² , voltage 1 to 100 V, electrolysis time 1 second to 5 minutes. Alternatively, the method of electrolyzing at high current density in sulfuric acid described in US Pat. No. 1,412,768 can be used. Among these, the one using an electrolytic solution containing sulfuric acid is the most excellent in terms of stain resistance during printing and wide water width. The amount of anodized film formed is 1
-50 mg / dm ² is suitable, and preferably 10-4.
It is 0 mg / dm ² .

After the anodizing treatment, a sealing treatment may be performed if necessary. Sealing treatment is boiling water treatment, steam treatment,
Specific examples include sodium silicate treatment and dichromate aqueous solution treatment. Further, the aluminum support is subjected to undercoating treatment with an aqueous solution of a resin having a cationic quaternary ammonium group, a water-soluble polymer compound such as polyvinylphosphonic acid, starch and cellulose, and a metal salt such as fluorinated zirconic acid. You can also

The photopolymerizable photosensitive layer of the photosensitive lithographic printing plate according to the invention usually contains a polymer binder, an addition-polymerizable compound having at least one ethylenically unsaturated double bond and a photopolymerization initiator. The photopolymerizable composition is applied onto the support that has been subjected to the above treatment and dried to form.

In the present invention, the addition-polymerizable compound having at least one ethylenically unsaturated double bond (hereinafter abbreviated as "ethylenic compound") means that the photopolymerizable composition has been exposed to actinic rays. In this case, a compound having an ethylenic double bond that undergoes addition polymerization by the action of a photopolymerization initiator and is cured, for example, a monomer having an ethylenically unsaturated double bond, or a side chain or main chain It is a polymer having an ethylenically unsaturated double bond. In addition, what is meant by the monomer in the present invention is a concept facing a so-called polymer substance. Therefore, it includes dimers, trimers and oligomers in addition to the narrowly defined monomers.

Examples of the monomer having an ethylenically unsaturated double bond include unsaturated carboxylic acids; esters of aliphatic polyhydroxy compounds and unsaturated carboxylic acids; aromatic polyhydroxy compounds and unsaturated carboxylic acids. ester;
Examples thereof include esters obtained by an esterification reaction of an unsaturated carboxylic acid with a polyvalent carboxylic acid and a polyvalent hydroxy compound such as an aliphatic polyhydroxy compound and an aromatic polyhydroxy compound. The ester of the aliphatic polyhydroxy compound and the unsaturated carboxylic acid, ethylene glycol diacrylate, triethylene glycol diacrylate, trimethylol propane triacrylate, trimethylol ethane triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, Acrylic esters such as pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and glycerol acrylate, methacrylic acid esters in which acrylates of these exemplified compounds are replaced by methacrylates, and similarly itaconate is replaced. Itaconic acid ester, crotonic acid ester replaced with crotonate There are maleic acid esters in which instead of the maleate.

Examples of the ester of an aromatic polyhydroxy compound and an unsaturated carboxylic acid include hydroquinone diacrylate, hydroquinone dimethacrylate, resorcin diacrylate, resorcin dimethacrylate and pyrogallol triacrylate.

The ester obtained by the esterification reaction of an unsaturated carboxylic acid with a polyvalent carboxylic acid and a polyvalent hydroxy compound is not necessarily a single substance, but representative specific examples include acrylic acid, phthalic acid and Condensates of ethylene glycol; condensates of acrylic acid, maleic acid and diethylene glycol; condensates of methacrylic acid, terephthalic acid and pentaerythritol; condensates of acrylic acid, adipic acid, butanediol and glycerin.

Examples of other ethylenic compounds include:
Urethane acrylates such as addition reaction between tolylene diisocyanate and hydroxyethyl acrylate; Epoxy acrylates such as addition reaction between diepoxy compound and hydroxyethyl acrylate; Acrylamides such as ethylene bis acrylamide; Acrylic acid such as diacrylic phthalate Esters; vinyl group-containing compounds such as divinyl phthalate are useful.

Examples of the above-mentioned polymer having an ethylenically unsaturated double bond in the main chain include a polyester obtained by a polycondensation reaction of an unsaturated divalent carboxylic acid and a dihydroxy compound, and an unsaturated divalent carboxylic acid. There are polyamides and the like obtained by polycondensation reaction with diamine. As the polymer having an ethylenically unsaturated double bond in the side chain, a divalent carboxylic acid having an unsaturated bond in the side chain, for example, itaconic acid, prohylidene succinic acid, ethylidene malonic acid, etc. and dihydroxy or diamine compound, etc. There is a condensation polymer with. Further, a polymer having a functional group having a reactive activity such as a hydroxy group or a methyl halide group in its side chain, for example, polyvinyl alcohol, poly (2-hydroxyethyl methacrylate), polyepichlorohydrin, etc. and acrylic acid, methacrylic acid, croton. A polymer obtained by a polymer reaction with an unsaturated carboxylic acid such as an acid can also be preferably used.

Of the above-mentioned ethylenic compounds, acrylic acid ester or methacrylic acid ester monomers are particularly preferably used. Furthermore, among the ethylenic compounds,
Examples of the monomer having an ethylenically unsaturated double bond other than the above include a phosphoric acid ester compound having at least one (meth) acryloyl group, and a photopolymerizable photosensitive composition containing the same is used. In particular, the effect of the present invention is more remarkably exhibited when this is combined with an aluminum support anodized using an electrolytic solution containing sulfuric acid.

The phosphoric acid ester compound having at least one (meth) acryloyl group is not particularly limited as long as it is a phosphoric acid ester and has at least one (meth) acryloyl group in its structure. More specifically, examples include those represented by the following general formula (I).

[0021]

[Chemical 2]

(In the general formula (I), R ¹ represents a hydrogen atom or a methyl group, Q represents a divalent alkylene chain having 1 to 25 carbon atoms, n represents an integer of 1 to 2, and m represents In the formula (I), n is preferably 1, and Q is preferably 1 to 10, particularly 1 to 4 carbon atoms. When the phosphoric acid ester compound is included, 1 out of all ethylenic compounds
-50% by weight is preferred.

Next, the photopolymerization initiator will be described. As the photopolymerization initiator, any one that can initiate the polymerization of the compound having at least one ethylenically unsaturated double bond can be used. In particular, any one can be suitably used as long as it has photosensitivity to light rays in the visible region. Among these, examples of the activator that generates an active radical by inducing some action with the photoexcited sensitizer include, for example, hexaarylbiimidazoles, titanocene compounds, halogenated hydrocarbon derivatives, diaryl iodonium salts, organic peroxides. An oxide etc. can be mentioned. Of this,
A system using hexaarylbiimidazoles or a titanocene compound is preferable because of good sensitivity, storability, adhesion of the coating film to the substrate and the like.

Various hexaarylbiimidazoles can be used, for example, 2,
2'-bis (o-chlorophenyl) -4,4 ', 5
5'-tetra (p-fluorophenyl) biimidazole, 2,2'-bis (o-bromophenyl) -4,
4 ', 5,5'-tetra (p-iodophenyl) biimidazole, 2,2'-bis (o-chlorophenyl)-
4,4 ', 5,5'-Tetra (p-chloronaphthyl) biimidazole, 2,2'-bis (o-chlorophenyl)
-4,4 ', 5,5'-Tetra (p-chlorophenyl)
Biimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (p-chloro-p-
Methoxyphenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) biimidazole, 2,
2'-bis (o-chlorophenyl) -4,4 ', 5
5'-tetra (o, p-dibromophenyl) biimidazole, 2,2'-bis (o-bromophenyl) -4,
4 ', 5,5'-tetra (o, p-dichlorophenyl)
Examples thereof include biimidazole and 2,2′-biso, p-dichlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole. These biimidazoles can be used in combination with other types of biimidazoles, if necessary. Biimidazoles are described, for example, in Bull. Chem. Soc. Japan,
33, 565 (1960) and J. Org. Che
m, 36 [16] 2262 (1971).

As the titanocene compound, various compounds can be used, for example, JP-A-59-1523.
It can be appropriately selected and used from various titanocene compounds described in JP-A-96 and JP-A-61-151197. More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-
Ti-bis-2,3,4,5,6-pentafluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,3,5,6, -tetrafluorophen-1-yl, Di-cyclopentadienyl-Ti-bis-2,4
6-trifluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-di-fluorophenyl-
1-yl, di-cyclopentadienyl-Ti-bis-
2,4-di-fluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6
-Tetrafluorophen-1-yl, di-methylcyclopentadienyl-Ti-bis-2,6-difluorophen-1-yl, di-cyclopentadienyl-Ti-bis-2,6-difluoro-3 -(Pyr-1-yl) -phen-1-yl etc. can be mentioned.

Next, the sensitizer of the photopolymerization initiator will be described. The sensitizer in the present invention means a compound capable of effectively generating an active radical upon irradiation with visible light when coexisting with the above-mentioned activator. Examples of typical sensitizers include, for example, U.S. Pat. No. 3,479,18.
No. 5, such as leuco crystal violet and triphenylmethane leuco dyes such as leucomalachite green, photoreducing dyes such as erythrosine and eosin Y, US Pat. No. 3,549,367. , U.S. Pat. No. 3,652,275, and other aminophenyl ketones such as Michler's ketone and aminostyryl ketone, U.S. Pat. No. 3,844,7.
Β-diketones shown in US Pat. No. 90, indanones found in US Pat. No. 4,162,162,
Ketocoumarins disclosed in JP-A-52-112681, aminostyrene derivatives and aminophenylbutadiene derivatives disclosed in JP-A-59-56403, and US Pat. No. 4,594,310. Aminophenyl heterocycles, US Pat. No. 4,966,83
Jurolidine heterocycles shown in Japanese Patent No.
Examples include the pyrromethene dyes disclosed in JP-A-241338.

Further, the photopolymerization initiator used in the present invention may optionally contain 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 3-mercapto 1,2,4-triazole,
The photopolymerization initiation ability can be further enhanced by adding a hydrogen donating compound such as N-phenylglycine or N, N-dialkylbenzoic acid alkyl ester. Of these, particularly preferred are compounds having a mercapto group such as 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole and 3-mercapto 1,2,4-triazole.

Next, the polymer binder will be described. This is a component that imparts film forming ability and viscosity adjusting ability, and an alkali-soluble polymer binder, particularly a polymer binder having a carboxyl group in the molecule, is preferably used. Specific examples of the polymer binder having a carboxyl group in the molecule include (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, maleic acid,
(Meth) acrylonitrile, styrene, vinyl acetate, vinylidene chloride, maleimide or other homopolymers or copolymers,
Other examples include polyethylene oxide, polyvinylpyrrolidone, polyamide, polyurethane, polyester, polyether, polyethylene terephthalate, acetyl cellulose, polyvinyl butyral and the like. Among them, a copolymer containing at least one kind of (meth) acrylic acid ester and (meth) acrylic acid as a copolymerization component is preferable. The preferred acid value of the polymer binder having a carboxyl group in the molecule is 10 to 250, and the preferred weight average molecular weight (hereinafter abbreviated as Mw) is 5,000 to 50.
In many cases.

These polymer binders preferably have an unsaturated bond in their side chains, and particularly preferably have at least one unsaturated bond represented by the following general formula (II).

[0030]

[Chemical 3]

(In the formula, R ² represents a hydrogen atom or a methyl group. R ^{3 to} R ⁴ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, Sulfo group, nitro group, cyano group, optionally substituted alkyl group, optionally substituted aryl group, optionally substituted alkoxy group, optionally substituted Optionally substituted aryloxy group, optionally substituted alkylamino group, optionally substituted arylamino group, optionally substituted alkylsulfonyl group, or substituent Represents an arylsulfonyl group which may have
Represents an oxygen atom, a sulfur atom, an imino group, or an alkylimino group. )

The substituent such as an alkyl group which may have a substituent is not particularly limited as long as the reactivity of the carbon-carbon double bond is not extremely reduced, but it is usually a halogen atom, an alkyl group or phenyl. Group, cyano group, nitro group, alkoxy group, alkylthio group, dialkylamino group, or the like. Among these, those in which R ² is a hydrogen atom or a methyl group and R ³ and R ⁴ are each independently a hydrogen atom, a lower alkyl group, an alkoxy group, a dialkylamino group, or a cyano group are more preferable.

As a polymer binder containing a carboxyl group in the molecule and further having an unsaturated bond in the side chain, a polymer bond having a carboxyl group in the molecule as described in Japanese Patent Application No. 9-346144. A compound obtained by reacting a part of the carboxyl group of the agent with an epoxy group-containing unsaturated compound can be mentioned.

Examples of the epoxy group-containing unsaturated compound include glycidyl (meth) acrylate, allyl glycidyl ether, α-ethyl glycidyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl asocrotonate, itaconic acid monoalkyl ester monoglycidyl ester. Examples thereof include aliphatic epoxy group-containing unsaturated compounds such as fumaric acid monoalkyl ester monoglycidyl ester and maleic acid monoalkyl ester monoglycidyl ester, and alicyclic epoxy group-containing unsaturated compounds represented by the following structures.

[0035]

[Chemical 4]

(In each general formula, R ⁸ represents a hydrogen atom or a methyl group. R ⁹ represents a divalent aliphatic saturated hydrocarbon group having 1 to 6 carbon atoms.) Although the main components of the polymerizable composition have been described in detail, their preferable use ratio is
Among the photopolymerization initiators, the sensitizer is preferably 0.01 to 20 parts by weight, particularly preferably 0.05 to 10 parts by weight, and the activator is preferably 0.1 to 100 parts by weight of the ethylenic compound. 80 parts by weight, particularly preferably 0.5 to 50 parts by weight, the polymer binder is preferably 10 to 400 parts by weight,
It is particularly preferably in the range of 20 to 200 parts by weight.

The photopolymerizable composition may further contain other substances in addition to the above-mentioned constituents, depending on the purpose of use. For example, thermal polymerization inhibitors such as hydroquinone, p-methoxyphenol, and 2,6-di-t-butyl-p-cresol; coloring agents composed of organic or inorganic dyes and pigments; dioctyl phthalate, didodecyl phthalate, tricresyl. Plasticizers such as phosphates, sensitivity improving agents such as tertiary amines and thiols, and other additives such as dye precursors can also be added.

The above-mentioned various additives are preferably added in an amount of 2 parts by weight or less of the thermal polymerization inhibitor, 20 parts by weight or less of the colorant, 40 parts by weight or less of the plasticizer, and the dye precursor, relative to 100 parts by weight of the ethylenic compound. It is generally in the range of 30 parts by weight or less. The photopolymerizable composition described above is diluted with an appropriate solvent, coated on the support and dried to form a photosensitive layer. As a coating method, dip coating,
Coating rod, spinner coat, spray coat,
It can be applied by a known method such as roll coating. The coating film thickness is 1.2 to 4 g / m as a dry film thickness.
^{When the} thickness is less than ² , the storage stability is deteriorated (sensitivity is lowered, defective during development), and when it is thick, the sensitivity is insufficient and the effect of the present invention is not sufficiently exerted. It is preferably 1.2 to 3.5 g / m ² . The drying temperature is preferably 30 to 150 ° C, particularly preferably 40 to 110 ° C.

On the upper layer of the photopolymerizable photosensitive layer in the photosensitive lithographic printing plate of the present invention, a protective layer is provided as an oxygen blocking layer for preventing the polymerization inhibiting action by oxygen. The protective layer usually contains a water-soluble polymer binder and includes various known water-soluble polymer compounds, and specific examples thereof include water-soluble polymer compounds such as polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide and cellulose. Can be mentioned. The weight average molecular weight of the water-soluble polymer is 1000
It is about 300,000. Of these, polyvinyl alcohol having a particularly high oxygen gas barrier property is preferable.

These water-soluble polymers are used alone or as a mixture, and a surfactant is preferably added for the purpose of improving the coating property on the photosensitive layer. As a coating method, it is possible to apply by a well-known coating method like the photosensitive layer. The coating film thickness needs to be ² to 7 g / m ² as a dry film thickness. If it is thinner than this, the sensitivity is insufficient, and if it is thick, the storability is deteriorated, and defective defects during development due to sensitivity decrease occur. Occurs, and the effect of the present invention is not fully exhibited.
The drying temperature is generally 30 to 110 ° C, preferably 40 to 70 ° C.

The developer used in the present invention is an aqueous solution containing an alkali metal silicate. As the alkali metal silicate, potassium silicate, sodium silicate, lithium silicate,
There are potassium metasilicate, sodium metasilicate, etc., and other inorganic alkalis such as potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium triphosphate, sodium diphosphate, sodium carbonate, potassium carbonate, sodium bicarbonate, etc. Agent and an alkaline agent such as an organic amine compound such as trimethylamine, diethylamine, isopropylamine, n-butylamine, monoethanolamine, diethanolamine and triethanolamine may be used in combination.

The developer of the present invention preferably further contains a surfactant. As the surfactant used in the developer of the present invention, for example, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether and other polyoxyethylene alkyl ethers, polyoxyethene "octylphenyl ether, poly Polyoxyethylene alkyl allyl ethers such as oxyethylene nonyl phenyl ether, polyoxyethylene alkyl esters such as polyoxyethylene stearate, sorbitan monolaurate, sorbitan monostearate, sorbitan distearate, sorbitan monooleate, sorbitan Sorbitan alkyl esters such as sesquioleate and sorbitan trioleate, glycerol monostearate,
Nonionic surfactants such as monoglyceride alkyl esters such as glycerol monooleate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, sodium butylnaphthalenesulfonate, sodium pentylnaphthalenesulfonate, sodium hexylnaphthalenesulfonate, octylnaphthalenesulfonate Alkylnaphthalene sulfonates such as sodium,
Alkyl sulfates such as sodium lauryl sulfate, alkyl sulfonates such as sodium dodecyl sulfonate, anionic surfactants such as sulfosuccinate ester salts such as sodium dilauryl sulfosuccinate; alkyl betaines such as lauryl betaine and stearyl betaine Although amphoteric surfactants such as amino acids can be used, anionic surfactants such as alkylnaphthalene sulfonates are particularly preferable.

These surfactants can be used alone or in combination. The content of these surfactants in the developer is preferably 0.1 to 5% by weight in terms of active ingredient. The developer referred to in the present invention means not only an unused liquid used at the start of development but also a PS
A replenisher is replenished in order to correct the activity of the solution which is lowered by the treatment of the plate, and the solution contains the solution whose activity is maintained (so-called running solution).

The developer referred to in the present invention is actually PS.
It refers to the one that is in the state of processing the plate. In addition to the above components, the developer of the present invention may contain the following components, if desired. For example, benzoic acid, phthalic acid, p-
Ethylbenzoic acid, pn-propylbenzoic acid, p-isopropylbenzoic acid, pn-butylbenzoic acid, pt-butylbenzoic acid, pt-butylbenzoic acid, p-2-hydroxyethylbenzoic acid, decanoic acid, salicylic acid, 3- Organic carboxylic acids such as hydroxy-2-naphthoic acid; isopropyl alcohol,
Organic solvents such as benzyl alcohol, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, propylene glycol and diacetone alcohol; other than these, chelating agents, reducing agents, dyes, pigments, water softeners, preservatives and the like can be mentioned.

The exposure light source used in the processing method of the present invention is a laser, specifically, a helium cadmium laser,
Examples thereof include an argon ion laser, a YAG laser, a helium neon laser and the like. According to the processing method of the present invention, after the laser exposure, it is developed with the above-mentioned developing solution without heat treatment. The development is performed by a known method such as dip development and spray development.

In the processing method of the present invention, after this development processing,
Furthermore, it is characterized in that the entire surface is exposed (post-exposure).
The light source is not particularly limited, but for example,
Carbon arc, high pressure mercury lamp, xenon lamp, metal
Ride lamp, fluorescent lamp, tungsten lamp, halo
Examples include Gen lamps. Emitted from these light sources
When the wavelength of the light is limited by a filter etc.
possible. Also, the exposure amount after that is not particularly limited.
No effect, the larger the effect, the more efficient the plate process
Meaning 10 mJ / cm²1000 mJ / c or more
m ²The following are preferred.

[0047]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Synthesis of polymer binder-1 Methyl methacrylate / isobutyl methacrylate / isobutyl acrylate / methacrylic acid = 35/20 /
Copolymer of 10/35 mol% (charge ratio), Mw = 7
200 parts by weight (hereinafter abbreviated as "stem resin-1"), 75 parts by weight of the following alicyclic epoxy group-containing unsaturated compound, p-
2.5 parts by weight of methoxyphenol, 8 parts by weight of tetrabutylammonium chloride, and 800 parts by weight of propylene glycol monomethyl ether acetate were added to the reaction vessel, and the mixture was stirred and reacted in air at 110 ° C. for 24 hours to give a polymer binder-1. (Oxidation 60, unsaturated group reacts with 60% of the whole methacrylic acid component of the trunk resin-1) to obtain a solution.

[0049]

[Chemical 5]

Synthesis of Polymer Binder-2 α-Methylstyrene / acrylic acid copolymer (trade name “SCX-690” manufactured by Johnson, oxidation 240,
Mw = 15,000) 855 parts by weight, the following alicyclic epoxy-containing unsaturated compound 490 parts by weight, p-methoxyphenol 1.3 parts by weight, tetraethylammonium chloride 4.3 parts by weight, propylene glycol monomethyl ether acetate 1800 Add 12 parts by weight to the reaction vessel,
Polymer binder with stirring reaction at 0 ° C for 15 hours in air
2 (oxidation about 170, unsaturated group reacts with about 50% of the whole methacrylic acid component of SCX-690) to obtain a solution.

[0051]

[Chemical 6]

Support-1 An aluminum plate was degreased with 3% sodium hydroxide, and this was degreased in a 18.0 g / l nitric acid bath at 25 ° C. and 80 A / dm ^2.
Etching at a current density of 15 seconds and then at 50 ° C for 1 second.
% Sodium hydroxide aqueous solution for 5 seconds, and then neutralized for 5 seconds at 25 ° C. 10% nitric acid aqueous solution.
After washing with water, anodization was performed in a 30% sulfuric acid bath at 30 ° C. and 10 A / dm ² for 16 seconds, followed by washing with water and drying to obtain Ra of 0.55.
A support-1 of μm was obtained.

Support-2 Aluminum plate was degreased with 3% sodium hydroxide, and this was degreased in a 11.5 g / l hydrochloric acid bath at 25 ° C. and 80 A / dm ^2.
Etching at a current density of 11 seconds and then at 50 ° C for 1 second.
% Sodium hydroxide aqueous solution for 5 seconds, and then neutralized for 5 seconds at 25 ° C. 10% nitric acid aqueous solution.
After washing with water, anodization was performed in a 30% sulfuric acid bath at 30 ° C. under the conditions of 10 A / dm ² for 16 seconds, followed by washing with water and drying to obtain Ra of 0.63.
A support-2 of μm was obtained.

Support-3 (Comparative Support) Ra was determined in the same manner as in Support-1, except that the etching conditions in the nitric acid bath were changed to a current density of 40 A / dm ² and an etching time of 5 seconds. A support-3 of 0.3 μm was obtained.

Production of Photosensitive Lithographic Printing Plates 1 to 9 The following photopolymerizable composition coating liquid was applied to the above-mentioned Supports 1, 2 or 3 using a bar coater and dried. On top of this,
A polyvinyl alcohol aqueous solution was applied and dried to form a protective film, and photosensitive planographic printing plates-1 to 9 were prepared. The dry film thickness of each is shown in Table 1.

Photopolymerizable composition coating liquid Ethylenic monomer shown in Table-1 Total 55 parts by weight Polymeric binder shown in Table-1 45 parts by weight Compound of the following structure (A) 2.0 parts by weight The following structure (B) Titanocene compound 10 parts by weight 2-mercaptobenzothiazole 5.0 parts by weight N, N-dimethylbenzoic acid ethyl ester 10 parts by weight Copper phthalocyanine pigment 3.0 parts by weight Cyclohexanone 1090 parts by weight

[0057]

[Chemical 7]

[0058]

[Chemical 8]

[0059]

[Table 1]

Abbreviations in the column of ethylenic monomer in Table 1 indicate the following, respectively. 1: PM-2 manufactured by Nippon Kayaku Co., Ltd.

[0061]

[Chemical 9] 2: Shin-Nakamura Chemical Co., Ltd. UA-306H

[0062]

[Chemical 10] 3: DPHA manufactured by Nippon Kayaku Co., Ltd.

[0063]

[Chemical 11]

(Examples 1 to 7 and Comparative Examples 1 to 6)
Argon laser (light intensity)
130 μJ / cm ², Wavelength 488 nm) inner drum type
Scanning exposure was performed. Photosensitive plane exposed as above
Plate printing plates -1 to 9 are processed with automatic processor HL-860X (Mitsubishi
Development process using the developer shown in Table-2.
It made sense. The temperature of the developer is 30 ° C, and the transport speed is 60c.
m / min.

Then, a part of the above printing plate was post-exposed with a mercury lamp (150 mJ / cm ² ) according to Table-2. The obtained printing plate was put on a printing machine (Roland RP-1) to perform a printing durability test. The printing durability was evaluated in the state of 2% small dots in the image area after printing 100,000 sheets (◯: 80% or more reproduction, ×: reproduction rate less than 80%).

Further, after the preparation of the photosensitive lithographic printing plates-1 to 9 and after a lapse of half a year, the same plate making was carried out and a printing durability test was conducted. At that time, the dampening water was forcibly squeezed to stain the entire surface, and then the water was supplied again, and the stain resistance was evaluated by the number of prints required until the stain was recovered (○: less than 20 sheets, ×: 20).
More than one).

[0067]

[Table 2]

[0068] * Developer-1 (pH = 10.8)   Potassium silicate (JIS A potassium silicate) 3% by weight   Perex NBL (manufactured by Kao Corporation) 5% by weight     (Sodium alkylnaphthalene sulfonate; content 35%)   92% by weight of water Developer-2 (pH = 11.0)   Sodium carbonate 0.5% by weight   Perex NBL (manufactured by Kao Corporation) 5% by weight     (Sodium alkylnaphthalene sulfonate; content 35%)   Water 94.2% by weight

[0069]

According to the present invention, since it is possible to omit the post-exposure heating, the printing plate making process by CTP is not impaired and the printing durability and stain resistance after storage are good. This makes it possible to secure stable printing performance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI G03F 7/09 501 G03F 7/09 501 7/11 501 7/11 501 (56) Reference JP-A-9-236911 (JP, JP, 236911 A) JP 54-18305 (JP, A) JP 5-100438 (JP, A) JP 6-273923 (JP, A) JP 10-48839 (JP, A) JP 10 -10719 (JP, A) JP-A-9-244233 (JP, A) JP-A-5-72735 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F ^7/ 00- 7/42

Claims (8)

(57) [Claims] 1. The center line average roughness (Ra) is 0.35 μm.
A photosensitive lithographic printing plate obtained by sequentially laminating a photopolymerizable photosensitive layer having a film thickness of 1.2 to 4 g / m ^{2 and} a protective layer having a film thickness of ^{2 to} 7 g / m ² on the above support was subjected to laser exposure. Then, a method for processing a photosensitive lithographic printing plate is characterized by developing with a developer containing an alkali metal silicate, and then exposing the entire surface. 2. The thickness of the photopolymerizable photosensitive layer is 1.2 to 3.5.
The method for treating a photosensitive lithographic printing plate according to claim 1, wherein the method is g / m ² . 3. The method for treating a photosensitive lithographic printing plate as claimed in claim 1, wherein the support is an aluminum support which has been anodized by using an electrolytic solution containing sulfuric acid. 4. The photosensitive lithographic printing plate as claimed in claim 1, wherein the photopolymerizable photosensitive layer contains a phosphoric acid ester compound having at least one (meth) acryloyl group. Processing method. 5. The method for treating a photosensitive lithographic printing plate according to claim 4, wherein the phosphoric acid ester compound having a (meth) acryloyl group is a compound represented by the following general formula (I). [Chemical 1] (In the general formula (I), R ¹ represents a hydrogen atom or a methyl group, Q represents a divalent alkylene chain having 1 to 25 carbon atoms, n represents an integer of 1 to 2, m represents 1 or 2) Is shown.) 6. A mercury lamp is used as a light source for overall exposure after development.
A photosensitive lithographic printing plate according to any one of claims 1 to 5.
Processing method. 7. The method according to claim 6, wherein the mercury lamp is a high pressure mercury lamp.
Photosensitive lithographic printing How to process the plate. 8. The total exposure amount after development is 10 to 10
00 mJ / cm ² The method according to any one of claims 1 to 7, wherein
Method for processing the photosensitive lithographic printing plate described above.