JPH04148992A - Preparation of support for planographic printing - Google Patents

Abstract

PURPOSE:To provide the title support excellent in printing durability and made possible in the development due to an aqueous developing solution by treating the surface of an aluminum plate with an alkaline solution having a specific pH range to form a hydrated oxide film and subjecting the aluminum plate having the hydrated oxide film to anodic oxidation in a sulfuric acid electrolyte. CONSTITUTION:It is pref. to subject an aluminum plate to graining prior to providing a hydrated oxide film. The hydrated oxide film can be formed by immersing the aluminum plate in an alkaline solution having pH 8-12. No film is obtained in the short-time treatment of the aluminum plate in an acidic solution and, therefore, no close adhesiveness is obtained. In order to prepare a support having good close adhesiveness, the aluminum plate is pref. treated under a condition of pH8-12 and temp. 50-100 deg.C. Continuously, by subjecting the surface of the aluminum plate having the hydrated oxide film thus provided thereto to anodic oxidation in sulfuric acid, an anodic oxide film is provided on the hydrated oxide film. Succeedingly, hydrophilizing treatment is applied to the surface of the anodic oxide film of the aluminum plate thus treated. In this hydrophilizing treatment, a method for immersing the aluminum plate in a JIS No.3 sodium silicate aqueous solution is generally employed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a support for a lithographic printing plate, and more specifically, it relates to a method for producing a support for a lithographic printing plate, and more specifically, it relates to a method for producing a support for a lithographic printing plate. The present invention relates to a method for producing a support for a lithographic printing plate that has adhesiveness, high sensitivity, and high printing durability.

(Prior art) In the printing industry, photosensitive lithographic printing plates (PS plates) have become the mainstream of printing plates because they are extremely easy to handle and contribute to labor savings in the platemaking and printing process. It is widely used in general commercial printing, newspaper printing, form printing, paper carton printing, etc.

Recently, there has been an increasing demand for further labor-saving and speeding up of the plate-making and printing process, and new plate-making systems and automation systems have been proposed. A photosensitive lithographic printing plate with excellent properties is desired. For example, conventionally, when forming an image on a photosensitive planographic printing plate, the original film is vacuum-adhered to the photosensitive planographic printing plate and light is irradiated.
Recently, a method of forming an image by directly enlarging and projecting a microfilmed original onto a photosensitive lithographic printing plate has begun to be put into practical use. In addition, a method of forming an image by scanning and exposing the photosensitive layer on a photosensitive lithographic printing plate directly with visible light or ultraviolet light from a laser such as an argon ion laser is beginning to be put into practical use.

However, in order to form an image using the new exposure method as described above, much higher sensitivity than the conventional method is required. In addition to this demand for improved sensitivity, improvements regarding developing processing solutions are also desired.

In other words, conventional processing solutions have mainly been based on organic solvents, but there are issues with the labor and safety environment, processing costs, and
Recently, there has been a demand for an aqueous developing solution.

In order to obtain a highly sensitive photosensitive lithographic printing plate, it is necessary that the photosensitive layer in the image area strongly adheres to the support surface and that the lithographic printing plate has high printing durability, and that the non-image area after development is or stain resistant is required.

In order to strengthen the adhesion between the photosensitive layer and the support, a method of anodizing the support in phosphoric acid (Japanese Patent Publication No. 46-26
No. 521, JP-A No. 62-99198, JP-A No. 55-1
2877, Special Publication No. 54-37522)
, a method of anodic oxidation in a mixed acid of phosphoric acid and sulfuric acid (Japanese Patent Application Laid-open No.
5-28400, Japanese Patent Application Laid-open No. 53-2103,
U.S. Patent No. 4.049°504, British Patent Section 1.24
No. 0.577, etc.), a method of anodizing in phosphoric acid and then further anodizing in an organic acid (e.g., polyvinylposponic acid or phytic acid) (JP-A-57-89)
497, Japanese Patent Application Laid-open No. 57-89498, the specification of U.S. Pat. Anodic oxidation method in sulfuric acid or boric acid
-193298, Japanese Patent Publication No. 46-431.23, etc.) are known. Additionally, a method of anodizing in a phosphoric acid compound (e.g., Na3PO4, NaH2PO4, Na3PO4, etc.) (Japanese Patent Application Laid-Open No. 60-56073,
JP-A-59-15644 and JP-A-60-52596) or a combination of these methods are well known. However, since all of these methods use phosphorus compounds, eutrophication of the drainage system is unavoidable, which can cause red tide and putrefaction of lake water.
Since this is unfavorable from an environmental standpoint, there has been a desire to develop an alternative solution, that is, a solution that does not contain phosphorus compounds and can be used for anodic oxidation.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a device that has extremely high sensitivity applicable to the above-mentioned new exposure method, has excellent printing durability, and can be developed with an aqueous developer; Another object of the present invention is to provide a method for producing a support for a lithographic printing plate that provides a lithographic printing plate with excellent printability.

(Means for Solving the Problems) An object of the present invention is to improve the surface of an aluminum plate from p118 to 1
Production of a support for a lithographic printing plate characterized by treating with an alkaline solution in step 2 to form a hydrated oxide film, and then anodizing the aluminum plate having the hydrated oxide film in a sulfuric acid electrolyte. This is accomplished by a method.

The present invention will be explained in detail below.

The aluminum plate used in the lithographic printing plate support of the present invention may be pure aluminum commonly used for lithographic printing plates, or aluminum plate containing metals such as silicon, copper, manganese, magnesium, chromium, zinc, and nickel. Examples include aluminum alloys. Its shape may be sheet-like.

Before applying the hydrated oxide film, the aluminum plate should be grained according to conventional methods by brush (mechanical) graining, chemical graining, electrolytic graining, or a combination thereof. preferable.

A hydrated oxide film is provided on the surface of the aluminum plate treated in this way. By forming the hydrated oxide film before anodizing, it is possible to increase the adhesion between the support and the photosensitive layer described below.

This hydrated oxide film can be formed by immersing an aluminum plate in an alkaline solution having a pH of 8 to 12.

When immersed in an acidic solution, the film cannot be broken down even after a short treatment, and therefore adhesion cannot be obtained. Treatment with a neutral solution may not provide good adhesion, but it requires an immersion time of at least 5 minutes, which is disadvantageous in terms of industrial production. With short processing time,
In order to obtain good adhesion, it is preferable to treat with an alkaline solution, but if the solution is p+ (13 or more), the aluminum substrate will be severely etched and dissolved, making it impossible to form a uniform water use film.However, for a short time, It is possible to form a film with excellent adhesion by processing at low temperature (for example, 50°C for 15 seconds), but it has the drawback of lacking stability.Therefore, it has good adhesion suitable for the purpose of the present invention. 5 on p148-12 to create a support with
It is preferable to process at a temperature of 0°C to OOoC.

Examples of the alkaline agent used in the above solution include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide, ammonia, triethanolamine, Amines such as jetanolamine and monoethanolamine are used.

Further, if necessary, a surfactant such as saponin that improves surface wettability may be contained.

The processing time is appropriately selected from the range of 5 seconds to 100 seconds.

The surface of the aluminum plate provided with the hydrated oxide film is then anodized in sulfuric acid to form an anodic oxide film on the hydrated oxide film.

The sulfuric acid electrolyte used for this anodization has a sulfuric acid concentration of 50 to
300g/f and Aj? 3 “As an ion,
It is preferable that it contains 3 to 15 g/12.

Further, it is preferable to perform anodization at a temperature of 20 to 70°C, and the current density is preferably 3 to 2 OA/dm2,
Electrolysis time is 5 seconds to obtain an oxide film of desired thickness.
300 seconds is preferred. Furthermore, the thickness of the anodic oxide film is preferably 0.1 to 5 μm.

The surface of the anodic oxide film of the aluminum plate thus treated is subsequently subjected to a hydrophilic treatment. As for such hydrophilic treatment, it is known whether it is a method of immersion in JISS No. sodium silicate aqueous solution or a general method.
Known methods such as treatment with potassium fluorozirconate as shown in US Pat. No. 63, polyvinylphosphonic acid as shown in US Pat.

A photosensitive composition is coated on the aluminum support thus obtained to a dry film thickness of about 0.5 to 5 g/m, and a photosensitive layer is provided on the support. A lithographic printing plate is obtained.

Examples of the photosensitive layer used in the present invention include a photodimerizable photosensitive layer and a photopolymerizable photosensitive layer.

Photodimerizable photosensitive layer The photocrosslinkable polymers used in the photodimerizable photosensitive layer include maleimide groups, cinnamyl groups, cinnamoyl groups, cinnamylidene groups, cinnamylidene acetyl groups, chalcone groups, etc. in the side chains or main chains. Examples include polymers with

As a polymer having a maleimide group in the side chain,
No. 2'-988 (corresponding U.S. Pat. No. 4.079041)
Publications, German Patent No. 2.626.769, European Patent No. 21.019, European Patent No. 3.552, German Patent No. 2.626.769, European Patent No. 3.552, German Patent No. Die Angewan
dteMakromolekulare Chemie
) 115 (1983), pages 163 to 181 of the following - Shipman (■): (wherein R1 and R2 each independently represent an alkyl group having up to 4 carbon atoms, or R1 and R
2 may be taken together to form a 5- or 6-membered carbon ring. ) A polymer having a maleimide group in its side chain,
JP-A-49-1.28991, JP-A No. 491, 28992
No. 49-128993, No. 50-5376, No. 5(]-5377, No. 505379, No. 50-53
No. 78, No. 50-5380, No. 51-5298, No. 53-5299, No. 53-5300, No. 5C1-5
No. 0107, No. 5i-47940, No. 52-1390
7, German Patent No. 50-45076, German Patent No. 52-121700, German Patent No. 50-10884, German Patent No. 50-45087, German Patent No. 2.349.948, German Patent No. 2.616.276
The following - Mariner (II) (in the formula,
R3 represents an aromatic group, and R4 represents a hydrogen atom, a halogen atom, an alkyl group or a cyano group. ) Polymers having a maleimide group in the side chain can be mentioned. The average molecular weight of these polymers is 1000 or more, preferably 30,000 to 500,000. Furthermore, these polymers have an average of two or more maleimide groups per molecule in their side chains.

Making these polymers having maleimide groups in their side chains soluble or swellable in alkaline water can be achieved by including acid groups in the polymers.

Specific examples of acid groups include carboxylic acid, sulfonic acid, phosphoric acid, phosphonic acid, alkali metal salts and ammonium salts thereof, and those with a pKa of 6 to 1 that dissociate with alkaline water.
2 acid group, specifically, SO□NHCO--CONH
CO--302NIiCOO-It is also possible to copolymerize one to three types of monomers having these acid groups with a monomer having a maleimide group. These acid group-containing monomers and maleimide group-containing monomers are mixed, for example, at 10
/90-50150, preferably 20/80"-40
A photocrosslinkable polymer can be easily obtained by copolymerizing at a ratio of /60 (mole ratio).

The acid value of maleimide polymers having acid groups is 30 to 300.
The range is preferably from 50 to 250, more preferably from 50 to 250. Preferable monomers having an acid group that can be copolymerized include vinyl monomers having a carboxyl group such as acrylic acid and methacrylic acid, maleic anhydride, itaconic anhydride, and the like.

Among the polymers containing these acid groups, Die-Angebandte Macromolecule Chemie
Angewandteλ(akromolekular
e Chemie) 1.28 (1984) 71-91
Copolymers of Il-C2-(methacryloyloxy)ethyl)-2,3-dimethylmaleimide and methacrylic acid or acrylic acid, as described on page 1, are useful. Furthermore, by copolymerizing a vinyl monomer as a third component during the synthesis of this copolymer, it is possible to easily synthesize a multicomponent copolymer according to the purpose. For example, flexibility can be imparted to the copolymer by using, as the third component vinyl monomer, an alkyl methacrylate or alkyl acrylate whose homopolymer has a glass transition point below room temperature.

Among other photocrosslinkable polymers having a cinnamyl group, a cinnamoyl group, a cinnamylidene group, a cinnamylidene acetyl group, a chalcone group, etc. in the side chain or main chain, those having photosensitive main chains, such as U.S. Pat. No. 3.030.208 No. 3.45
There are photosensitive polyesters described in the specifications of No. 3.237 and No. 3.622.320. The above polyesters are prepared by condensing a suitable polycarboxylic acid, or a lower alkyl ester of a suitable polycarboxylic acid, or a chloride with a suitable polyhydric alcohol in the presence of an esterification catalyst.

Examples of these photocrosslinkable polymers solubilized in alkaline water include the following.

Namely, as described in JP-A-60-191244, the main chain has a photodimerizable unsaturated double bond adjacent to the aromatic nucleus, the side chain has a carboxyl group, and the terminal has a hydroxyl group. Chain extenders having two or more functional groups in the molecule that can react with hydroxyl groups, such as diisocyanate compounds, diphenyl terephthalate, etc., are added to the polyester prepolymer.
The photosensitive polymer obtained by reacting diphenyl carbonate, terephthaloyl bis(N-caprolactam), etc. has an unsaturated double bond in the main chain that can be photodimerized adjacent to an aromatic nucleus, and a hydroxyl group at the end. Examples include photosensitive polymers in which carboxyl groups are introduced into side chains by reacting pyromellitic dianhydride or cyclobenkune tetracarboxylic dianhydride as a chain extender with polyester prepolymers or polyurethane prepolymers having I can do it.

Furthermore, photosensitive polymers having an acid value of 20 to 200 and soluble or swellable in alkaline water and having a photodimerizable functional group in the side chain and a carboxyl group in the side chain can be mentioned. These photosensitive polymers are disclosed in Japanese Patent Application Laid-Open No. 62-175729.
No., JP-A-62-175730, JP-A-63-254
No. 43, JP-A-63-218944, JP-A-63-2
It is described in each publication of No. 1.8945.

Note that the photocrosslinkable polymer used in the present invention includes:
It is desirable to use a molecular weight of 1,000 or more, preferably 10,000 to 500,000, particularly preferably 20,000 to 300,000.

The amount of the photocrosslinkable polymer added to the photodimerizable photosensitive layer is 10 to 99% by weight, preferably 50 to 90% by weight.
It is.

A sensitizer may be used in the photodimerizable photosensitive layer used in the present invention. As such a sensitizer, 300
Triplet sensitizers are preferred which have an absorption maximum in the range above nmJU that allows practically sufficient light absorption.

Such sensitizers include benzophenone derivatives, benzanthrone derivatives, quinones, aromatic nitro compounds,
Examples include naphthothiazoline derivatives, benzothiazoline derivatives, thioxanthones, naphthothiazole derivatives, ketocoumarin compounds, penzothiazole derivatives, naphthofuranone compounds, pyrylium salts, thiapyrylium salts, and the like. Specifically, Michler's ketone, N, N'-diethylaminobenzophenone, benzanthrone, (3
-Methyl-1,3-diaza-1,9-benz) anthrone picramide, 5-dil-roacenaphthene, 2-chlorothioxanthone, 2-isopropylthioxanthone, dimethylthiogysanthone, methylthioxanthone-1-ethylcarboxylate, 2-Nitrofluorene, 2-dibenzoylmethylene-3-methylnaphthothiapurine, 3
, 3-carbonyl-bis(7-dinithylaminocoumarin), 2.4.6-driphenyldiapyrylium perchlorate, 2-(p-chlorobenzoyl)naphthothiazole, and the like. The amount of these sensitizers added is about 1 to 20% by weight of the photosensitive layer, more preferably 3 to 20% by weight.
10% by weight is appropriate.

The photodimerizable photosensitive layer used in the present invention may further contain a binder, if necessary, and is usually added as appropriate to the linear organic polymer. Specific examples of binders include chlorinated polyethylene, chlorinated polypropylene, polyacrylic acid alkyl esters, copolymers of acrylic acid alkyl esters and at least one monomer such as acrylonitrile, vinyl chloride, styrene, butadiene, polyamides, Examples include methyl cellulose, polyvinyl formal, polyvinyl butyral, methacrylic acid copolymers, acrylic acid copolymers, and itaconic acid copolymers.

In some cases, for the purpose of coloring the photosensitive layer, a dye or a pigment, a pH indicator as a print-out agent, etc. may be added.

Furthermore, a plasticizer or the like may be added to the photodimerization type photosensitive layer. As the plasticizer, phthalic acid dialkyl esters such as dibutyl phthalate and dibutyl phthalate, oligoethylene glycol alkyl esters, phosphate ester plasticizers, and the like can be used.

Photopolymerizable photosensitive layer The polymerizable compound having an ethylenically unsaturated bond in the photopolymerizable composition used for the photopolymerizable photosensitive layer refers to a compound having at least one ethylenically unsaturated bond in its chemical structure. It has chemical forms such as monomers, prepolymers, dimers, trimers and other oligomers, mixtures thereof, and copolymers thereof.

Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyhydric amine compounds, and the like.

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid,
These include maleic acid.

Salts of unsaturated carboxylic acids include the alkali metal salts of the aforementioned acids, such as the sodium and potassium salts.

Specific examples of esters of aliphatic polyhydric alcohol compounds and unsaturated carboxylic acids include acrylic esters, such as ethylene glycol diacrylate, triethylene glycol diacrylate, 3-butanediol diacrylate, tetramethylene glycol diacrylate, Propylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerys lithium diacrylate,
Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate,
Examples include polyester acrylate oligomers.

Examples of methacrylic acid esters include tetramethylene glycol dimethacrylate, I-lyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethyl glycol dimethacrylate, 1,3-butanediol dimethacrylate, and pentaerythritol dimethacrylate. methacrylate, pentaerythritol trimethacrylate,
Dipentaerythritol dimethacrylate, sorbitol trimethacrylate-1, sorbitol tetramethacrylate, bis-[p(3-methacryloxy-2-hydroxypropoxy) phenylfudimethylmethane, bis[
Examples include p(methacryloxyethoxy)phenylfudimethylmethane. Examples of itaconic acid esters include ethylene glycol shiitaconate, propylene glycol shiitaconate, 1,3-butanediol shiitaconate, 1,4-butanediol shiitaconate, tetramethylene glycol shiitaconate, and pentaerythritol shiitaconate. , sorbitol tetrataconate, etc. As the crotonic acid ester, ethyl
Examples include non-griny dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, sorbitol tetramaletone, and the like. Isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, sorbitol tetraisocrotonate, and the like.

Examples of maleic esters include ethylene glycol simarate, triethylene glycol simarate, pentaerythritol simarate, sorbitol tetramaleate, and the like. Furthermore, mixtures with the aforementioned esters may also be mentioned.

Specific examples of amides of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, and 1,6-hexamethylene bis-methacryl. Amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide, and the like.

As another example, the following general formula (1
Examples include vinyl urethane compounds containing two or more polymerizable vinyl groups in one molecule to which a vinyl monomer containing a hydroxyl group as shown in 111) is added.

C1(2=C(R5)COOCI(2CH(R6)OH
(III) (However, R5 and R6 represent a hydrogen atom or a methyl group.) Examples of the photopolymerization initiator used in the photopolymerizable photosensitive layer include those disclosed in U.S. Pat. No. 2,367,660. Vicinal polyketaldonyl compounds, U.S. Patent No. 2.3
67,661 and 2.367,670, U.S. Patent No. 2.4
48.828, aromatic acyloin compounds substituted with a hydrocarbon at the α-position as disclosed in U.S. Pat. No. 2,722.512, U.S. Pat. No. 046.127 and No. 2.
951.758, the triarylimidazole dimer/p-aminophenyl ketone combination disclosed in U.S. Pat. 870.5
Benzothiazole compounds disclosed in U.S. Patent No. 24, benzothiazole compounds/trihalomethyl-5 disclosed in U.S. Pat. No. 4,239,850
-) Riazine compounds and U.S. Patent No. 3.751.25
The acridine and phenazine compounds disclosed in U.S. Pat. No. 9, the oxadiazole compounds disclosed in U.S. Pat. Approximately 0.5 based on weight
It ranges from % to about 15% by weight, preferably from 2 to 10% by weight.

Examples of the alkaline water-soluble or swellable and film-formable polymer used in the photopolymerizable photosensitive layer include benzyl (meth)acrylate/(meth)acrylate as described in Japanese Patent Publication No. 59-44615. Acrylic acid/other addition-polymerizable vinyl monomer copolymers as necessary;
Methacrylic acid/methyl methacrylate (or ethyl methacrylate) copolymer as described in Japanese Patent Publication No. 54-34327: Others: Japanese Patent Publication No. 58-1.2577, Japanese Patent Publication No. 51-25957, Japanese Patent Publication No. 51-25957, 54-92723
(Meth)acrylic acid copolymer as described in each publication; Allyl (meth)acrylate/(meth)acrylic acid as described in JP-A No. 59-53836/as required Other addition-polymerizable vinyl monomer copolymers include those obtained by adding pentaerythritol triacrylate to the maleic anhydride copolymer described in JP-A-5971048 through half-esterification, and vinyl methacrylate-1~/ - in polymers such as methacrylic acid/other addition-polymerizable vinyl monomer copolymers as required
Cool(,-PO,)I2,-3 O3H1-8O□
NH2,302N11CO- group, acid value 50-20
0 acidic vinyl copolymers can be mentioned.

In particular, benzyl (meth)acrylate/(meth)acrylic acid/other addition-polymerizable vinyl monomer copolymers and allyl (meth)acrylate/as required
(Meth)acrylic acid/other addition-polymerizable vinyl monomer copolymers as required are suitable.

These high molecular weight polymers can be used alone or as a mixture of two or more types. The molecular weight of the high molecular weight polymer is
Although it can take a wide range of values depending on the type of polymer, it is generally from 5,000 to 1,000,000, preferably from 10,000 to 500,000. The amount of the polymer used is 10 to 90% by weight, preferably 30% by weight based on the total photopolymerizable composition.
~85% by weight.

Furthermore, it is preferable to incorporate a thermal polymerization inhibitor and an antioxidant into the photopolymerizable and photodimerizable photosensitive layer, such as hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, Useful examples include t-butylcatechol, benzoquinone, 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), and 2-mercaptobenzimidazole. It is mentioned as something.

'' The two photopolymerizable and photodimerizable photosensitive layers contain a photosensitive composition composed of the above-mentioned components, for example, 2-methoxyethanol, 2-methoxyethyl acetate, methyl cellosolve, propylene glycol monomethyl ether, 3-methoxy propatool, 3-methoxyethyl acetate,
Dissolved in a suitable solvent such as acetone, methyl ethyl ketone, ethylene dichloride, methyl lactate, ethyl lactate, methanol, dimethyl formamide, ethanol, methyl cellosolve acetate-1, etc. alone or in a mixed solvent of an appropriate combination thereof, and coated on the support. It is formed by setting. The coating amount is about 0.1 g/I to about 1 g/I after drying.
Appropriate range is 0g/rrr, preferably 0.5~
5 g/mr.

Furthermore, in addition to the above-mentioned photopolymerizable and photodimerizable photosensitive layer, a photosensitive layer made of a diazo resin or a photosensitive layer made of a ○-quinonediazide resin may be provided on the lithographic printing plate support of the present invention. .

In the present invention, an intermediate layer may be provided as necessary for the purpose of increasing the adhesion between the support and the photosensitive layer, preventing the photosensitive layer from remaining after development, or preventing halation. good. In order to improve adhesion, the intermediate layer is generally made of a diazo resin or a phosphoric acid compound that adsorbs to aluminum, for example. Further, the intermediate layer made of a highly soluble substance so that no photosensitive layer remains after development is generally made of a highly soluble polymer or a water-soluble polymer. Additionally, for antihalation purposes, the interlayer typically includes dyes and UV absorbers.

The thickness of the intermediate layer is arbitrary, and it must be thick enough to perform a uniform bond-forming reaction with the upper photosensitive layer when exposed to light. Generally, a dry solid coating rate of about 1 to 100 .mu./rd is good, and a coating rate of 5 to 40 .mu./rd is especially good.

The intermediate layer contains a sensitizer, diazo stabilizer,
Various compounds such as polymeric binders, antihalation agents, surfactants, etc. can be used.

In addition, in order to prevent negative effects such as decreased sensitivity and deterioration of storage stability due to oxygen, a removable transparent cover sheet is further provided on the photosensitive layer of the photosensitive lithographic printing plate used in the present invention, or an oxygen permeable It is also possible to provide a coating layer of a waxy material with low viscosity, a water-soluble or alkali-soluble polymer, or the like.

A printing plate can be obtained by imagewise exposing and developing the photosensitive lithographic printing plate of the present invention according to a conventional method.

The exposure light source used at that time is carbon arc,
A general-purpose light source including ultraviolet rays and visible light having a wavelength of 180 nm or more can be suitably used, such as a high-pressure mercury lamp, a xenon lamp, a metallolide lamp, an argon ion laser, a helium cadmium laser, and a krypton laser.

Further, as a developer, dilute alkaline water, preferably 10
Dilute alkaline water containing up to 96 volumes of organic solvent is used.

As alkaline compounds for the dilute alkaline water, inorganic compounds such as caustic soda, caustic potash, lithium hydroxide, sodium silicate, and sodium bicarbonate, and organic compounds such as ammonia and monoethanolamine are used. Further, as the water-soluble solvent for dilute alkaline water, isopropyl alcohol, benzyl alcohol, ethyl cellosolve, diacetone alcohol, etc. can be used. Such a developer may contain a surfactant, a dye, a salt for suppressing swelling, and a salt that corrodes the base metal.

(Effects of the Invention) A lithographic printing plate using the lithographic printing plate support of the present invention has extremely high sensitivity applicable to new exposure methods, has excellent printing durability, and can be developed with an aqueous developer. Furthermore, the adhesion of the photosensitive layer is strong and printability is excellent.

Example 2 A suspension of 0% pumice and water was applied to the surface of an aluminum plate, and the surface was mechanically grained with a rotating nylon brush. The surface roughness was 0.15 μm. Continuing, 5
% NaOH aqueous solution for 50° CIO seconds, and then immersed in a 60° Cl2O% H2SO4 aqueous solution for neutralization.

The aluminum plate thus obtained was treated with H2SO4
Using ρ) II, 3. Solution adjusted to 5, p
1] 6 ion exchange water, pH 8,9°1 using KOH
．． 0,11. ．． 12. Add the solution adjusted to 13 to +00°C.
After soaking for 30 seconds, 170 g/(!H2So4 and 8
g/IAl2'' in an electrolyte containing ions, 30'
Anodized at a current density of C110A/dm2, the surface was
A coating of g/ni' was provided. Next, after immersing in an aqueous solution of JISS No. 2.5% sodium silicate at 70'C for 10 seconds, a photosensitive composition (1) having the following composition was applied at a dry weight of 1.0 g/r.
It was applied so that it became d.

Photosensitive composition ■ N-C2-(methacryloyloxy)ethyl)-2,3-dimethylmaleimide/methacrylic acid-65/35 (molar ratio) copolymer
5g sensitizer below
0.3g Propylene glycol monomethyl ether methyl ethyl ketone 50g Defensor-MCF-323 (manufactured by Dainippon Ink & Chemicals @) 0.03
g Oil Blue #603 (manufactured by Orient Kagaku Kogyo ■) 0.07g The thus obtained photosensitive lithographic printing plate was exposed to 10 counts of light using an eye rotary printer with a Fuji Photo Film step guide in close contact with it. Developing was carried out at 25°C for 50 seconds using developer solution (1) having the following composition. the result,
A good image could be formed.

Furthermore, this photosensitive lithographic printing plate was exposed and developed as follows. A transparent negative film obtained by reducing the size of character lines on a 35mm film was enlarged 6 times using a projection exposure machine equipped with a mercury lamp light source (SA, PP', manufactured by Dainippon Screen Manufacturing Co., Ltd.). After projecting and exposing the photosensitive planographic printing plate for 20 seconds, it was developed using developer solution (3).

As a result, it was possible to form good character lines.

Developer I After development processing, on the surface, Apply commercially available tape. hand, A test was conducted to peel off the photoresist film.

The result The results are shown in the table below.

From the table above, it can be seen that a lithographic printing plate with good adhesion can be obtained by processing for a short time (30 seconds) at pH 8 to 12.

Claims (1)

[Claims] A lithographic printing plate characterized by treating the surface of an aluminum plate with an alkaline solution having a pH of 8 to 12 to form a hydrated oxide film, and then anodizing the aluminum plate having the hydrated oxide film in a sulfuric acid electrolyte. Method for manufacturing a support for