JPH0714670B2 - Process for producing photosensitive lithographic printing plate support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for producing a photosensitive lithographic printing plate support, and in particular, the anodic oxide film is modified to improve the contamination of non-image areas. The present invention relates to a method for producing a lithographic printing plate support made of an aluminum plate.

[Conventional technology]

Conventionally, a lithographic printing plate has a so-called PS plate in which a photosensitive composition is applied in a thin layer on an aluminum plate, but the above-mentioned aluminum plate is usually a mechanical method such as a brush grain method or a ball grain method or It is subjected to a surface-roughening treatment such as an electrochemical method such as an electrolytic grain method or a method combining both methods, and after the surface is made satin-finished, it is etched with an aqueous solution of acid or alkali, and further anodized. After that, a hydrophilic treatment is optionally applied to form a support for a lithographic printing plate, and a photosensitive layer is provided on the support to obtain a PS plate (photosensitive lithographic printing plate). This PS plate is usually subjected to image exposure, development, correction and gumming steps to obtain a lithographic printing plate, which is attached to a printing machine for printing.

However, the above PS plate is exposed to light and developed, and the non-image area of the lithographic printing plate obtained is irreversibly adsorbed by the substance contained in the photosensitive layer and contaminates the non-image area. There is a problem that it is difficult to distinguish the image part from the non-image part, or the correction marks are clearly left and the plate surface becomes uneven, and when the degree of the correction becomes severe, the plate becomes dirty and cannot be used as a printing plate.

In order to improve this, conventionally, a method of immersing an anodized aluminum support surface in an aqueous alkali metal silicate solution as described in U.S. Pat.No. 3,181,461, U.S. Pat.No. 3,860,426. A method of subbing hydrophilic cellulose containing a water-soluble metal salt, or a method of subbing sodium arylsulfonate as described in British Patent No. 2,098,627 has been proposed. . By performing such a treatment, it is possible to prevent the above-mentioned non-image portion from being contaminated and prevent "smudge" from occurring on the printed matter. There was a drawback with the new problem of decreasing to 50-80%.

Further, conventionally, a method of providing a thin layer of trihydroxybenzolcarboxylic acid as described in JP-B-44-6410 on the surface of an aluminum support which is mechanically or electrolytically grained, or JP-B-41- A method of providing a thin layer of melitic acid as described in JP 14337, or a method of providing a thin layer of phosphonic acid and its derivative as described in JP-B-388907. It is known to apply it, and I tried to apply this method to an anodized aluminum plate, but there was a new problem that the stain on the non-image area was markedly worse than when the above treatment was not applied. . In particular, such a problem tends to become more prominent as the time from the production of the PS plate to the plate-making process (storage time) becomes longer.

Further, the conventional lithographic printing plate has a problem that stains occur because the ink adhering to the non-image area is not rapidly removed.

Thus, the lithographic printing plate that does not cause contamination of the non-image area has low printing durability, and the lithographic printing plate that does not cause deterioration of printing durability tends to have significant contamination of the non-image area. It was very difficult to satisfy at the same time.

[Object of the Invention]

Therefore, an object of the present invention is to provide a lithographic printing plate that is less likely to cause contamination in the non-image area, does not cause stains in the non-image area of the printed matter, and can obtain a lithographic printing plate with no reduction in printing durability. The purpose is to provide a support.

[Structure of Invention]

The present inventors have completed the present invention as a result of intensive studies to achieve the above object. According to the present invention, at least one surface of an aluminum plate is roughened, and then anodized, and then the anodic oxide film is dissolved in an acidic aqueous solution containing 0.01% by weight or more of carboxylic acid in an amount of 1 to 30% by weight of the total amount of the film. And a method for producing a support for a photosensitive lithographic printing plate.

Further, the present invention, at least one surface of the aluminum plate is subjected to a roughening treatment, then anodizing treatment, further carboxylic acid 0.
After dissolving the anodic oxide film in an acidic aqueous solution containing 01 wt% or more by 1 to 30 wt% of the total amount of the film, on the anodic oxide film,
A support for a photosensitive lithographic printing plate, comprising a hydrophilic layer containing a compound having at least one group selected from the group consisting of a hydroxyl group, a carboxyl group and a sulfonic acid group and an amino group or a salt thereof. It is a body manufacturing method.

Hereinafter, the present invention will be described in detail step by step.

(Aluminum Plate) The aluminum plate used in the present invention is a plate-shaped body such as pure aluminum containing aluminum as a main component or an aluminum alloy containing a slight amount of foreign atoms. Such foreign atoms include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of these foreign atoms is generally 10% by weight or less. Aluminum which is suitable for the support of the present invention is pure aluminum, but completely pure aluminum is difficult to produce due to the kneading technology, and therefore it is preferable that it contains as few foreign atoms as possible. As described above, the aluminum plate applied to the present invention is not specified in its composition, and conventionally known and officially used materials can be appropriately used. The thickness of the aluminum plate used in the present invention is approximately 0.1 mm to 0.5 mm.
The degree is appropriate.

(Roughening treatment) Prior to anodizing the aluminum plate, a degreasing treatment with a surfactant or an alkaline aqueous solution and a graining treatment for removing rolling oil on the surface are optionally carried out.

The graining treatment method includes a method of mechanically roughening the surface, a method of electrochemically melting the surface, and a method of chemically selectively melting the surface. As a method for mechanically roughening the surface, a known method called a hole polishing method, a brush polishing method, a blast polishing method, a buff polishing method or the like can be used. Further, as an electrochemical surface-roughening method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can be used.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment, if necessary.

(Anodic oxidation treatment) As the electrolyte used for the anodizing treatment of the aluminum plate, any electrolyte can be used as long as it forms a porous oxide film, and generally, sulfuric acid, phosphoric acid, oxalic acid, chromic acid or the like. The mixed acid is used, and the electrolyte and the concentration thereof are appropriately determined depending on the kind of the electrolyte. The treatment conditions for anodic oxidation cannot be unconditionally specified because it varies depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C, and the current density is 5 to 5.
A range of 60 A / dm ² , voltage of 1 to 100 V, and electrolysis time of 10 seconds to 50 minutes is suitable.

The amount of the anodized film is preferably 0.1 to 10 g / m ^2, but more preferably 1 to 6 g / m ² .

(Carboxylic Acid) The carboxylic acid used in the present invention may be any carboxylic acid as long as it chemically dissolves the anodized film as an aqueous solution. For example formic acid, acetic acid, propionic acid,
Oxalic acid, malonic acid, succinic acid, tartaric acid and the like can be used, and among the above-mentioned carboxylic acids, preferred acids are malonic acid, succinic acid, oxalic acid, formic acid and acetic acid.

Further, each of the above-mentioned carboxylic acids may simultaneously contain two or more kinds.

(Dissolution of anodized film) As described above, the anodized aluminum plate is subsequently treated with an acidic aqueous solution containing a carboxylic acid to form an oxidized film in an amount of 1 to 30% by weight, preferably 2 to 20% by weight of the total amount of the film. Dissolve. The dissolved amount of the anodized film is measured by a gravimetric method as shown in the following formula.

W _A : Total anodic oxide coating amount (g / m ² ), S: Sample area (m ² ), m ₁ : Sample weight before treatment (g), m ₂ : Sample weight after treatment (g), coating When the amount of dissolution is less than 1% by weight, the effect of preventing contamination of the non-image area by the components of the photosensitive layer is hardly obtained, and when it exceeds 30% by weight, the abrasion resistance of the non-image area is significantly reduced.

The treatment temperature can be arbitrarily selected from normal temperature to the boiling point, but in order to obtain a desired oxide film dissolution amount in a short time, it is better to carry out the treatment at a higher temperature.

It is suitable that the acidic aqueous solution containing carboxylic acid contains 0.01% by weight or more, preferably 0.1% by weight or more of carboxylic acid, and if it is less than 0.01% by weight, the effect of the present invention cannot be obtained.

The acidic aqueous solution preferably depends on the amount of carboxylic acid dissolved.
The pH is preferably 5 or lower, more preferably pH 3 or lower.

The temperature and processing time of the processing liquid cannot be uniquely determined due to the type of processing liquid and restrictions from the processing equipment, but generally the temperature is 30 to 100 ° C, and the processing time is in the range of 1 second to 5 minutes. Is.

The treatment method may be any method as long as the acidic aqueous solution is brought into contact with the oxide film, for example, a spray method or a dipping method.

(Hydrophilic layer) In a preferred embodiment of the present invention, after the treatment with the acidic aqueous solution as described above, a hydroxyl group as described in JP-A-60-149491 and JP-A-60-232998 is used. A hydrophilic layer containing a compound having at least one group selected from the group consisting of a carboxyl group and a sulfonic acid group and an amino group or a salt thereof (hereinafter referred to as a hydrophilic compound) is provided on the anodized film. .

Specific examples of the hydrophilic compound include amino acids such as aminoacetic acid, lysine, threonine, serine, aspartic acid, parahydrocyphenylglycine, dihydroxyethylglycine, anthranilic acid, and tryptophan.
Aliphatic aminosulfonic acids such as sulfamic acid and cyclohexylsulfamic acid and their sodium salts, potassium salts, ammonium salts, monoethanolamine, diethanolamine, trimethanolamine, tripropanolamine, triethanolamine and their hydrochlorides, Oxalates and phosphates are useful. Among these, triethanolamine, triethanolamine hydrochloride and dihydroxyethylglycine are most useful.

The hydrophilic compound as described above is a suitable solvent, for example, water,
A coating solution is prepared by dissolving it in alcohol such as methanol at a concentration of 0.001 to 10% by weight. At this time, it is appropriate that the pH after coating is in the range of 1 to 13. The temperature of the coating solution is
A range of 10 to 50 ° C is suitable.

As a coating method, any method such as dip coating, spin coating, spray coating and curtain coating may be used. The coating amount is 1 to 100 mg / m ² at a coverage after drying is preferred, more preferably from 5 to 50 mg / m ^2. When the coating amount is less than 1 mg / m ² , the effect of preventing stains on the non-image area becomes less effective.On the other hand, when it is more than 100 mg / m ² , the adhesion between the photosensitive layer and the support deteriorates, and Only lithographic printing plates with low power can be obtained.

Further, before or after providing this hydrophilic layer, U.S. Pat.
It can also be treated with an aqueous solution of an alkali metal silicate (eg sodium silicate) as described in No. 461.

(Photosensitive layer) By providing a conventionally known photosensitive layer on the thus obtained lithographic printing plate support, a photosensitive lithographic printing plate can be obtained. The lithographic printing plate thus obtained has excellent performance.

As the composition of the photosensitive layer, any composition can be used as long as the solubility or swelling property in a developing solution changes before and after exposure. The representative ones will be described below.

As a positive-working photosensitive diazo compound, Japanese Patent Publication No.
Most preferred are esters of benzoquinone-1,2-diazidesulfonic acid chloride and polyhydroxyphenyl described in JP-A-28403 or esters of naphthoquinone-1,2-diazidesulfonic acid chloride and pyrogallol-acetone resin. It is a thing. Other relatively suitable o-
Examples of quinonediazide compounds include U.S. Patent No. 3,046,120.
And benzoquinone-1,2-diazide sulfonic acid chloride or naphthoquinone-1,2-diazide sulfonic acid chloride described in U.S. Pat. No. 3,188,210 and phenol formaldehyde resin.

Although the o-quinonediazide compound alone constitutes the photosensitive layer, a resin soluble in alkaline water may be used in combination as a binder. As the resin soluble in alkaline water, there are novolac resins such as phenol formaldehyde resin, cresol formaldehyde resin, pt-butylphenol formaldehyde resin,
Examples include phenol-modified xylene resin and phenol-modified xylene / mesitylene resin. Other useful alkaline water-soluble resins include polyhydroxystyrene, copolymers of polyhalogenated hydroxystyrenated (meth) acrylic acid and other vinyl compounds.

Further details of the photosensitive layer comprising the o-quinonediazide compound and its developer are described in US Pat. No. 4,259,434.

 A photosensitive composition comprising a diazo resin and a binder.

As a negative-working photosensitive diazo compound, US Pat.
Diphenylamine-p-diazonium salt and formaldehyde, which are reaction products of the diazonium salt disclosed in each of 3,631 and 2,667,415 and an organic condensing agent containing a reactive carbonyl group such as aldol and acetal. Condensation products (so-called photosensitive diazo resins) with and are preferably used. Other useful fused diazo compounds are U.S. Patent No. 3,679,419, British Patent No. 1,312,925, 1,3
It is disclosed in each specification of No. 312,926. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from aqueous solutions. Also, these water-soluble diazo compounds are reacted with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups or both by the method disclosed in British Patent No. 1,280,885, The reaction product, a substantially water-insoluble photosensitive diazo resin, can also be used.

It can also be used as a reaction product with a hexafluorophosphate salt or a tetrafluoroborate salt as described in JP-A-56-121031.

In addition, the diazo resin described in US Pat. No. 1,312,925 is also preferable.

Such a diazo resin is used together with a binder. A preferred binder is an organic polymer having an acid value of 10 to 200, and specific examples thereof include a copolymer containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as an essential polymerization component, for example, U.S. Pat. Tertiary or quaternary with 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, acrylic acid or methacrylic acid and optionally other copolymerizable monomers as described in US Pat. Original copolymer, JP-A-53-12
No. 0903, the terminal is a hydroxy group, and acrylic acid or methacrylic acid esterified with a group containing a dicarboxylic acid ester residue, acrylic acid or methacrylic acid, and optionally other Copolymer with a monomer capable of copolymerization, a monomer having an aromatic hydroxyl group at the terminal as described in JP-A-54-98614 (for example, N- (4-hydroxyphenyl) methacrylamide) Etc.), acrylic acid or methacrylic acid, and optionally a copolymer with at least one other copolymerizable monomer, alkyl acrylates or methacrylates as described in JP-A-56-4144. , Acrylonitrile or methacrylonitrile, and an unsaturated carboxylic acid copolymer. Further, acidic polyvinyl alcohol derivatives and acidic cellulose derivatives are also useful.

A composition comprising a compound which undergoes dimerization upon irradiation with actinic rays. For example, polyvinyl cinnamate, polyvinyl cinnamoyl ethyl ether, polyethylene cinnamate acrylate and copolymers thereof, polyethyl cinnamate methacrylate and copolymers thereof, polyvalavinylphenyl cinnamate and copolymers thereof, polyvinyl benzal acetophenone And derivatives thereof, polyvinyl cinnamylidene acetate and derivatives thereof, allyl acrylate prepolymers and derivatives thereof, derivatives of polyester resins composed of paraphenylenediacrylic acid and polyhydric alcohol, and described in, for example, U.S. Pat.No. 3,030,208. There are such compounds as mentioned above.

A so-called copolymer composition that causes a polymerization reaction upon irradiation with actinic rays. For example, there is a composition comprising an addition-polymerizable unsaturated compound having two or more terminal ethylene groups described in US Pat. Nos. 2,760,863 and 3,060,023 and a photopolymerization initiator.

A resin, a sensitizer, a thermal polymerization inhibitor, a dye, a plasticizer and the like can be further added to the compound that dimerizes and the compound that undergoes a polymerization reaction upon irradiation with actinic rays as binders.

The photosensitive composition as described above is usually applied as a solution of water, an organic solvent, or a mixture thereof on the support according to the present invention and dried to prepare a photosensitive lithographic printing plate.

A suitable coating amount of the photosensitive composition is generally about 0.1 to about 5.0 g / m ² , and more preferably about 0.5 to about 3.0 g / m ² .

The photosensitive lithographic printing plate thus obtained is subjected to imagewise exposure with a light source containing an actinic ray such as a carbon arc lamp, a xenon lamp, a mercury lamp, a tungsten lamp, a metal halide lamp, and the like, and developed to obtain a lithographic printing plate.

(Effects of the Invention) A lithographic printing plate obtained by exposing and developing a photosensitive lithographic printing plate using the support obtained by the practice of the present invention has a negative type and a positive type in which the non-image area is contaminated. In addition, the image portion and the non-image portion can be easily identified in the correction process, and the correction mark does not occur, so that the printed matter is not stained by the correction mark. Moreover, the printing durability is high.

Furthermore, the aluminum support obtained by the practice of the present invention has a whiter surface than conventional ones, is excellent in plate inspection property, and is also excellent in ink stain recovery power.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples. In addition, "%" in the examples means "% by weight" unless otherwise specified.

[Example 1] The surface of a JIS1050 aluminum sheet was grained with a rotating nylon brush using a pumice-water suspension as an abrasive.
At this time, the surface roughness (centerline average roughness) was 0.5 μ. After washing with water, a 10% aqueous sodium hydroxide solution was immersed in a solution heated to 70 ° C., and etching was performed so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, it was immersed in a 30% aqueous solution of nitric acid for 1 minute for neutralization, and thoroughly washed with water. After that, in a 0.7% aqueous nitric acid solution, a short-wave alternating waveform having a voltage of 13 V for the anode and a voltage of 6 V for the cathode was used (the power supply waveform described in the example of JP-A-52-77702). After electrolytic surface roughening for 2 seconds, the surface was washed by immersing it in a 20% sulfuric acid solution at 50 ° C. and then washing with water.

Furthermore, the weight of the anodic oxide film is 3.0 g / m ^{2 in} 20% sulfuric acid aqueous solution.
So that it is anodized using direct current and washed with water,
It was dried to prepare a substrate (I).

An aqueous solution containing 1% oxalic acid (pH about 1.
0), about 10% of the total amount of anodic oxide film at 80 ° C (about 0.3g / m ² )
Was soaked that it was dissolved and subjected to etching treatment. Then, it was washed with water and dried.

The support [A] thus prepared was coated with a photosensitive solution having the following composition so that the coating weight after drying was 2.5 g / m ² to form a photosensitive layer.

The photosensitive lithographic printing plate made in this way was passed through a transparent positive film in a vacuum baking frame at a distance of 1 m for 3K.
After exposure for 50 seconds with a W metal halide lamp, the SiO ₂ / Na ₂ O molar ratio of sodium silicate of 1.74
It was developed with a 5.26% aqueous solution (pH = 12.7).

Then, after thoroughly washing with water to check the contamination of the non-image area, a part of the image area was erased with a commercially available erasing liquid, washed thoroughly with water, gummed, and printed by a conventional procedure. At this time, the generation of stains on the erased portion and the printing durability were examined. Furthermore, after ink is applied to the entire surface of the lithographic printing plate, the number of prints until a clean printed matter with no stain on the non-image area is obtained when printing is started by the usual procedure (hereinafter, ink stain recovery Called).

The above results are shown in Table 1.

[Comparative Example 1] A substrate [I] of Example 1 was prepared without carrying out an oxalic acid aqueous solution treatment, a support [A] was prepared, a photosensitive layer was provided in the same manner as in Example 1, and printing was performed in the same manner as in Example 1. I went to. The results are shown in Table 1.

Example 2 The substrate [I] of Example 1 was dissolved in an aqueous solution containing 1% formic acid (pH about 1.0) at 80 ° C. so that about 10% of the total amount of anodized film (about 0.3 g / m ² was dissolved). A support [B] was prepared by dipping, etching, washing with water and drying, a photosensitive layer was provided in the same manner as in Example 1, and printing was performed in the same manner as in Example 1. The results are shown in Table 1. Indicated.

[Comparative Example 2] The substrate [I] of Example 1 was treated with an aqueous solution (pH 1 or less) containing only about 1% of sulfuric acid at 80 ° C to form an anodized film of about 10% of the total amount.
Immersion treatment to dissolve, washing with water and drying, support [B]
It was created.

[Example 3] A support [C] was prepared by coating the support [A] of Example 1 with a dry layer of lysine, which is an organic compound, at 10 mg / m ² as a hydrophilic layer. A photosensitive layer was provided in the same manner as in Example 1, and printing was performed in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3] The substrate [I] of Example 1 was not treated with an aqueous carboxylic acid solution, and a hydrophilic layer similar to that of Example 3 was provided to prepare a support [C]. A photosensitive layer was provided in the same manner as in Example 1, and printing was performed in the same manner as in Example 1. The results are shown in Table 1.

From the results in Table 1, it can be seen that the support according to the method of the present invention has improved stains on the non-image areas and stains on the correction marks as compared with the support of the comparative example. Also, it can be seen that the ink stain recovery power is also excellent. Further, there is no decrease in printing durability.

Further, as an unexpected result, it was found that the effect of particularly reducing the contamination of the non-image area can be obtained by providing the hydrophilic layer after the method of the present invention.

Similar effects were obtained with malonic acid, succinic acid, and acetic acid.

[Example 4] The support [A] of [Example 1] was coated with a photosensitive solution having the following composition and dried to form a photosensitive layer. The dry coating amount of the photosensitive layer is 2.
It was 0 g / m ² .

Photosensitive liquid The photosensitive lithographic printing plate made in this way is passed through a transparent negative film in a vacuum baking frame from a distance of 1 m for 3K.
After exposure for 50 seconds using a W metal halide lamp, development was performed with a developing solution having the following composition, and gumming was performed with an aqueous solution of gum arabic to obtain a lithographic printing plate.

Developer After the contamination of the non-image area was examined, the printing evaluation was performed in the same manner as in [Example 1].

The results are shown in Table 2.

[Comparative Example 4] A substrate [1] of [Example 1] (support without oxide film treatment) was provided with a photosensitive layer in the same manner as in [Example 4], and printing evaluation was performed in the same manner.

The results are shown in Table 2.

As can be seen from Table 2, according to the method of the present invention, good results were obtained even in the case of the negative photosensitive layer.

Further, the same effect was obtained by using malonic acid, succinic acid, or acetic acid instead of oxalic acid as the treatment liquid for the oxide film to dissolve the oxide film.

Claims (6)

[Claims] 1. An aluminum plate is roughened on at least one side thereof, and then anodized, and then carboxylic acid is reduced to 0.
A method for producing a support for a photosensitive lithographic printing plate, which comprises dissolving an anodized film in an acidic aqueous solution containing not less than 01% by weight in an amount of 1 to 30% by weight of the total amount of the film. 2. The method for producing a photosensitive lithographic printing plate support according to claim 1, wherein the carboxylic acid is an aliphatic monocarboxylic acid or an aliphatic dicarboxylic acid. 3. The carboxylic acid is oxalic acid, malonic acid, succinic acid, formic acid or acetic acid.
A method for producing a support for a photosensitive lithographic printing plate as described in the item. 4. An aluminum plate is roughened on at least one side and then anodized, and further carboxylic acid is reduced to 0.
After dissolving the anodic oxide film in an acidic aqueous solution containing 01 wt% or more by 1 to 30 wt% of the total amount of the film, on the anodic oxide film,
A support for a photosensitive lithographic printing plate, comprising a hydrophilic layer containing a compound having at least one group selected from the group consisting of a hydroxyl group, a carboxyl group and a sulfonic acid group and an amino group or a salt thereof. Body manufacturing method. 5. The method for producing a photosensitive lithographic printing plate support according to claim 4, wherein the carboxylic acid is an aliphatic monocarboxylic acid or an aliphatic dicarboxylic acid. 6. The method according to claim 4 or 5, wherein the carboxylic acid is oxalic acid, malonic acid, succinic acid, formic acid or acetic acid.
A method for producing a support for a photosensitive lithographic printing plate as described in the item.