JPS6362795A - Production of support for planographic printing plate - Google Patents

Abstract

PURPOSE:To impart high printing durability and, at the same time, to make a non-image part hard to be contaminated, by a method wherein aluminum hydrate is formed to at least one surface of an aluminum plate to which said blasting is applied and the surface thereof is subsequently treated with silicate before being subjected to anodic oxidation treatment. CONSTITUTION:Aluminum hydrate is formed to an aluminum plate having a roughened surface by steam treatment, the immersion treatment in water at 60-100 deg.C or the immersion treatment in a dilute alkali solution at 60-100 deg.C to enhance the effect of hydrophilicity imparting treatment due to silicate performed thereafter. After silicate treatment, anodic oxidation treatment is further applied to said aluminum plate to obtain a support for a planographic printing plate having a surface forming a strong close bonding strength with an image part. The silicate treatment is performed by forming a silicate layer by an immersion method using alkali metal silicate, for example, sodium silicate or alkaline earth metal silicate treatment. When the photosensitive layer of a PS plate (Pre-Sensitized Plate) is provided on the support for the planographic printing plate thus obtained, a photosensitive planographic printing plate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a support for a lithographic printing plate, and in particular to a support for a lithographic printing plate made of an anodized aluminum plate having an improved hydrophilic layer. It's about the body.

[Conventional technology]

Conventionally, lithographic printing plates include so-called PS plates in which a photosensitive composition is coated in a thin layer on an aluminum plate, but the above aluminum plate is usually processed using a mechanical method such as the Brassdalein method or the Pallgrain method. The surface is roughened by an electrochemical method such as the electrolytic grain method, or a combination of both, and the surface is made into a matte finish.Then, the surface is etched with an aqueous solution of acid or alkali, and then anodized. After the treatment, a hydrophilic treatment is performed as desired to obtain a support for a planographic printing plate, and a photosensitive layer is provided on this support to obtain a PS plate (photosensitive planographic printing plate). This PS
The plate is usually subjected to imagewise exposure, development, correction, and gumming steps to form a lithographic printing plate, which is then mounted on a printing press and printed.

However, in the lithographic printing plate mentioned above, two of the positive effects
Substances contained in the photosensitive layer irreversibly adsorb to the non-image areas of the lithographic printing plate obtained by imagewise exposure and development of the third plate, contaminating the non-image areas. There have been problems in which it is difficult to identify the image area, and traces of correction remain clearly, resulting in an uneven plate surface, and if the degree of damage becomes severe, it becomes smudged, making it impossible to use it as a printing plate.

To remedy this, a method of immersing an anodized aluminum support surface in an alkali metal silicate as described in U.S. Pat. No. 3,181,461, U.S. Pat. No. 3,860 Hydrophilic cellulose priming methods containing water-soluble metal salts, as described in GB 2,098.626, or sodium arylsulfonate priming methods, as described in British Patent No. 2,098.627. Methods such as the law have been proposed. By performing such processing, it is possible to prevent the above-mentioned contamination of the non-image area and prevent "stains" from occurring on the printed matter, but on the other hand, the printing durability of the printed matter may be reduced if the above treatment is not applied The drawback was that it was accompanied by a new problem: a reduction of 30 to 80% of the case.

In addition, in order to improve the above-mentioned drawbacks caused by the presence of the anodic oxide film, JP-A-54-128453 and JP-A-55-28400 disclose that aluminum in the electrolyte that forms the anodic oxide film is Ion concentration 10-25
A method is disclosed in which the anodic oxidation is carried out to a significantly high value of g/12 or in a mixed electrolyte of sulfuric acid and phosphoric acid. . However, with this method, scale tends to form, a large amount of sludge (A I (DH) 3) is generated during waste liquid treatment, and it takes a lot of effort to control the acid concentrations of both sulfuric acid and phosphoric acid, which impairs production suitability. It had the disadvantage of being inferior. Furthermore, when anodic oxidation is performed at a high current density, a non-uniform anodic oxide film, so-called "scorch", may be formed due to significant film growth.

Furthermore, since the acid concentration in the electrolytic solution is low, the porosity of the formed anodic oxide film is significantly reduced, resulting in insufficient adhesion to the photosensitive layer, resulting in a reduction in rigidity to 80-90%.

The present inventors proposed a method for solving the above problem in a patent application filed in 1983-
It was proposed in No. 120675. That is, anodization treatment is performed, followed by hydrophilization treatment with metal silicate, and then water vapor or water at 60 to 100 °C or 60 to 100 °C
This is a method for producing a lithographic printing plate support which is treated with a dilute alkaline solution at .degree.

It is known that this surface treatment preserves the hydrophilic characteristics of the metal silicate and also strengthens the adhesion. However, the printing durability fluctuates widely depending on the printing conditions (there was a drawback that the printing durability was inferior to a substrate that had not been subjected to hydrophilic treatment using a metal silicate.Also, there was a method of applying a hydrophilic substance to the surface) JP-A No. 53-109705 proposes forming a hydrophilic intermediate layer before forming the anodic oxide film, but with this method, the formation of the parent layer on the surface is insufficient and the printing durability is also low. There is a tendency for it to be slightly inferior.

[Purpose of the invention]

An object of the present invention is to provide a support for a lithographic printing plate that does not reduce printing durability and is resistant to staining in non-image areas.

[Structure of the invention]

The present inventors have made intensive studies to achieve the above object, and as a result, have come up with the present invention. In other words, the present invention provides a method for processing an aluminum plate after graining, at least one side of the surface of the aluminum plate. This method of producing a support for a lithographic printing plate is characterized in that a hydrate of aluminum is formed on the surface of the aluminum hydrate, and then the surface thereof is subjected to a silicate treatment, and then anodization treatment is performed.

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

The aluminum plate used in the present invention is a plate-shaped body made of pure aluminum whose main component is aluminum or an aluminum alloy containing a trace amount of foreign atoms. This foreign atom is
These include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the alloy composition has a content of at most 10% by weight or less. Aluminum suitable for the present invention is pure aluminum, but
Since completely pure aluminum is difficult to produce due to smelting technology, it is preferable to use aluminum that contains as few foreign atoms as possible. In addition, if the aluminum alloy has the above-mentioned content,
It can be said that it is a material applicable to the present invention.

As described above, the composition of the aluminum plate applied to the present invention is not specified; conventionally known and publicly used materials can be used as appropriate.

The thickness of the aluminum plate used in the present invention is approximately 0.
．． It is about 1 mm to 0.5 mm. Prior to the graining treatment, in order to remove rolling oil from the surface of the aluminum plate, a degreasing treatment using a surfactant or an alkaline aqueous solution is performed, if desired. Thereafter, the aluminum plate is subjected to a graining treatment.

Graining treatment methods include a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically. As a method for mechanically roughening the surface, known methods such as ball polishing, brush polishing, blast polishing, puff polishing, etc. can be used.

Further, as an electrochemical surface roughening method, there is a method in which alternating current or direct current is used in a hydrochloric acid or nitric acid electrolyte.

Furthermore, a method combining the two can also be used, as disclosed in Japanese Patent Application Laid-Open No. 54-63902.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment as required.

After this, a treatment for forming an aluminum hydrate, which is a feature of the present invention, is performed. This hydrate formation can be carried out by steam, water at 60 to 100°C, or dipping in a dilute alkaline solution at 60 to 100°C;
Treatment with water is preferred. Through these treatments, aluminum hydrates (boehmite or payerite) are formed on the aluminum surface, which enhances the effect of the subsequent hydrophilic treatment with silicate (increases the amount of adsorption), and further improves the effect of the subsequent anodic oxidation. Through the treatment, a lithographic printing plate support having a surface that forms strong adhesion with the image area is obtained. When carrying out the treatment with water vapor, the temperature is preferably 100 to 120°C. Further, the pH of the dilute alkaline solution is preferably in the range of 7.5 to 12.5, and any alkaline agent may be used within this pH range. Typical alkali agents include M(OH)-, M
(CO3),,,M (CO,C00),,,M (B
Hydroxide, carbonate, acetate, etc. represented by the general formula of O*), 15Mm (P(]+) are used (where M represents ammonia, an alkali metal, and an alkaline earth metal. Also, n and m is an integer from 1 to 3).

Furthermore, alkaline acid salts such as sodium gluconate, sodium tartrate, and potassium tartrate can also be used, and organic amines such as ethanolamine can also be used.

In the case of treatment with water or a dilute alkaline solution, if the treatment liquid temperature is lower than 60° C., sufficient effects cannot be obtained even if the treatment is carried out for a long time, and only printing plates with low printing durability can be obtained. Therefore,
The treatment temperature is 60 to 100°C, and when using a dilute alkaline aqueous solution, the temperature is slightly lower, i.e. 60 to 80°C.
°C is preferred.

On the other hand, the treatment time is 60-100
In either case of treatment with water at 100°C or dilute aqueous alkaline solution at 60 to 100°C, a time of 10 seconds or more is appropriate, and a range of 10 seconds to 2 minutes is particularly preferred.

After forming an aluminum hydrate through such treatment, U.S. Pat.
As described in the specifications of Japanese Patent Publication No. 81.461, silicate eyebrows are formed by dipping with an alkali metal silicate, for example, sodium silicate, or
-194095 is carried out.

This aluminum plate is then subjected to an anodizing treatment. Any electrolyte that forms a porous oxide film can be used as the electrolyte for anodizing, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used - these electrolytes The concentration of is determined as appropriate depending on the type of electrolyte. The processing conditions for anodic oxidation vary depending on the electrolyte used, so they cannot be definitively specified, but generally the electrolyte temperature is 1 to 80% by weight solution, and the liquid temperature is 5 to 80% by weight.
70℃, current density 5-60 people/dm', voltage 1-10
0) It is appropriate if the electrolysis time is in the range of 10 seconds to 50 minutes.

The amount of the anodic oxide film is preferably in the range of 0.1 to 10 g/m', but more preferably in the range of 1 to 6 g/m'.

On the lithographic printing plate support obtained in this way,
23rd edition (Pre-3ensitized Plate
A photosensitive lithographic printing plate can be obtained by providing a conventionally known photosensitive layer as a photosensitive layer (abbreviation for ``(abbreviation)''), and the lithographic printing plate obtained by plate-making processing this plate has excellent performance. ing.

As the composition for the above-mentioned photosensitive layer, any composition can be used as long as its solubility or swelling property in a developer changes before and after exposure. The typical ones will be explained below.

■ As a positive-acting photosensitive diazo compound,
Ester of benzoquinone-1,2-diazide sulfonic acid chloride and polyhydroxyphenyl or ester of naphthoquinone-1,2-diazide sulfonic acid chloride and pyrogallol-acetone resin described in Publication No. 3-28-403 is the most preferred. Other relatively suitable 0-quinonediazide compounds include U.S. Pat. Nos. 3.046.120 and 3.188.210.
Benzoquinone-1,2 described in each specification of No.
- diazidesulfonic acid chloride or naphthoquinone - esters of 1°2-diazidesulfonic acid chloride and phenol formaldehyde resin.

Furthermore, polymer compounds having orthocarboxylic acid ester repeating units that are decomposed by acid as described in JP-A-56-17345, JP-A-60-102
Compounds containing silyl ester groups that are decomposed by acids as described in Publication No. 47 or JP-A-60-37
549.60-121446, a composition combining a compound containing a silyl ester group that decomposes and decomposes with an acid and a compound that generates an acid upon irradiation with light, and U.S. Pat. No. 3.849 Compounds containing ○-nitrocarbinol ester groups as described in No. 137 are useful.

The above-mentioned compound or composition constitutes the photosensitive layer by itself, but it is used together with a resin of this type as a binder, which is soluble in alkaline water. Examples of resins soluble in alkaline water include novolac resins having this property, such as phenol formaldehyde resin, cresol formaldehyde resin, pt-butylphenol-formaldehyde resin, phenol-modified xylene resin, and phenol-modified xylene/mesitylene resin. be.

Other useful alkaline water-soluble resins include polyhydroxystyrene, polyhalogenated hydroxystyrene (
Mention may be made of copolymers of meth)acrylic acid and other vinyl compounds. O in a composition comprising such an O-quinonediazide compound and a resin soluble in alkaline water.
- The amount of the quinonediazide compound is within the range of 10 to 50% by weight, and the ratio is usually about 20 to 40% by weight.

In addition, a cyclic acid anhydride, a dye as an image coloring agent, and other desired extenders (builers) can be appropriately added to the composition comprising the 0-quinonediazide compound in order to increase the sensitivity.

■A photosensitive composition consisting of a diazo resin and a binder.

As a negative-acting photosensitive diazo compound, US Patent No. 2.
Diphenylamine, which is a reaction product of the diazonium salt disclosed in No. 063.631 and No. 2.667, 415, and an organic condensing agent containing a reactive carbonyl group such as aldol or acetal. A condensation product of p-diazonium salt and formaldehyde (so-called photosensitive diazo resin) is preferably used. Other useful fused diazo compounds are U.S. Pat. No. 3.679.419, British Pat.
It is disclosed in each specification of No. 26. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts,
Therefore, it can be applied from an aqueous solution. These water-soluble diazo compounds can also be prepared by the method disclosed in British Patent No. 1.280.885: I-Aromatic or fatty compounds having one or more phenolic hydroxyl groups, sulfonic acid groups or both. It is also possible to use a substantially water-insoluble photosensitive diazo resin which is a reaction product of the reaction with a group compound.

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

In addition, diazo resins described in British Patent No. 1.312.925 are also preferred.

Such diazo resins are used together with binders. Preferred binders are organic polymers having an acid value of 10 to 200, and specific examples include copolymers containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential polymerization component, such as U.S. Pat. .123
．． 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, ternary or acrylic acid or methacrylic acid and optionally further copolymerizable monomers as described in No. 276. Quaternary copolymers, acrylic acid or methacrylic acid, acrylic acid or Copolymer of methacrylic acid and, if necessary, other copolymerizable monomers, JP-A-5
A monomer having an aromatic hydroxyl group at the end as described in No. 4-98614 (for example, N-(4-hydroxyphenyl) methacrylamide), acrylic acid or methacrylic acid, and optionally Copolymer with at least one other copolymerizable monomer, JP-A-56-
Copolymers of alkyl acrylates or methacrylates, acrylonitrile or methacrylonitrile, and unsaturated carboxylic acids as described in US Pat. No. 4,144 are included. Also acidic polyvinyl alcohol derivatives,
Acidic cellulose derivatives are also useful.

l ■ Composition consisting of a polymer compound containing a -CH=CH-C- group in the main chain or side chain of the polymer Polyester containing -CH=CH-C- as a photosensitive group in the main chain or side chain of the polymer Products based on photosensitive polymers such as polyamides, polycarbonates, etc., such as U.S. Pat. No. 3,030.208,
3.707.373 and 3.453□237
Compounds such as those described in the specifications of the No. 1); those derived from (2-probelidene) malonic acid compounds such as cinnamylidene malonic acid and difunctional glycols and whose main component is diphotosensitive polyesters. (For example, U.S. Patent No. 2
．． 956.878 and 3,173.787); silica of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose and the like; Dermic acid esters (e.g., U.S. Pat. No. 2,690.966, U.S. Pat. No. 2,752.3)
72, 2.732.301, etc.). These compositions may also contain sensitizers, stabilizers, plasticizers, pigments, dyes, and the like.

■ So-called photopolymerizable compositions that cause a polymerization reaction when irradiated with active light. For example, compositions comprising an addition polymerizable unsaturated compound having two or more terminal ethylene groups and a photopolymerization initiator as described in U.S. Pat. There is. - The compound that dimerizes and the compound that undergoes a polymerization reaction upon irradiation with actinic rays can further contain a resin as a binder, a sensitizer, a thermal polymerization inhibitor, a dye, a plasticizer, and the like.

The coating liquid for forming the photosensitive layer contains the above components,
For example, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 2-
Methoxyethyl acetate, 2-ethoxyethyl acetate, dimethylformamide, methanol, ethanol, n-propanol, 1-propanol, methylene chloride, ethylene dioxide, trichloroethane, monochlorobenzene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetic acid Methyl, ethyl acetate, acetic acid n
It is prepared by dissolving it in an organic solvent such as -propyl, isopropyl acetate, n-butyl acetate, ester such as methylaluminum acetate, or a mixed solvent thereof. The amount ratio of solid components in the coating liquid is about 0.1 to about 25% by weight,
More preferably 1 to 15% by weight or more.

The prepared coating solution is applied onto the aluminum plate treated as described above by various coating methods such as doctor coating, roller coating, 1:''-1' coating, and dip coating. Drying can also be done by applying conventional techniques, and is carried out in an atmosphere at a temperature ranging from room temperature to high temperature, for example from 20° C. to 150° C. After drying, the photosensitive layer has a weight of about 0.1 to 7 g/
m', and a more preferable amount is 0.5 to 4 g/m'.

The photosensitive lithographic printing plate thus obtained is imagewise exposed to light from a light source containing actinic radiation such as a carbon arc lamp, xenon lamp, mercury lamp, tungsten lamp, metal halide lamp, etc., and a suitable developer, such as the photosensitive composition described above, is applied to the photosensitive lithographic printing plate. When the photosensitive layer of item (1) is developed with an aqueous alkali solution such as potassium silicate, it becomes a lithographic printing plate.

〔Effect of the invention〕

The lithographic printing plate using the aluminum support obtained by the present invention has a remarkable effect that it has higher printing durability and is less likely to stain in non-image areas than a substrate that has been subjected to conventional hydrophilic treatment using silicate treatment. is obtained. Conventionally, lithographic printing plates with high printing durability tend to stain in non-image areas, and conversely, lithographic printing plates with less staining in non-image areas have low printing durability, so it is possible to improve both of these properties at the same time. This was considered extremely difficult.

However, the lithographic printing plate using the aluminum support according to the present invention has excellent properties not previously available, such as high printing durability and resistance to staining of non-image areas.

[Example] Hereinafter, the present invention will be described in more detail using Examples. Note that "%" in the examples indicates "% by weight" unless otherwise specified.

Example I The surface of a JIS 1050 aluminum sheet was grained with a rotating nylon brush using a vamisu water suspension as an abrasive. At this time, the surface roughness (center line average roughness) is 0.
It was 5μ. After washing with water, add 10% caustic soda solution to 70%
The aluminum surface was etched by immersing it in a solution heated to a temperature of 6 g/'m' so that the amount of dissolved aluminum was 6 g/'m'.

After washing with water, immerse it in a 30% nitric acid aqueous solution for 1 minute. Electrolytic surface treatment was performed for 20 seconds using the power waveform described above, and the surface was washed by immersing it in a solution of 30% nitric acid at 50° C., followed by washing with water.

Furthermore, in a 20% sulfuric acid aqueous solution, the weight of the anodized film was 3.
The substrate CA) was anodized using direct current so as to have a surface density of 0 g/m'', washed with water, and dried to prepare a substrate CA).

Substrate [A] was treated with No. 3 sodium silicate solution 2.5%, 70°C, 3
A substrate CBI on which a silicate layer film was formed by immersion for 0 seconds was prepared.

Substrate [A] was immersed in No. 3 sodium silicate, and then immersed in boiling water for 30 seconds to prepare substrate CC).

Further, after electrolytic surface roughening and acid cleaning, No. 3 sodium silicate immersion treatment and anodization treatment were performed to obtain a substrate [D], and comparative samples (AE to (Dl) were prepared.

Next, pre-treatment A for No. 3 sodium silicate immersion treatment of the substrate [D].
Samples of this example were prepared using boiling water and a triethanol aqueous solution.

Substrate [E] was treated with boiling water for 30 seconds, substrate [F] was treated with boiling water for 15 minutes, and substrate (Gl) was treated with triethanol aqueous solution 0°1'VOβ% 60°C for 2 minutes. ] to CG] were provided with the following photosensitive layers so that the coating weight after drying was 2.5 g/m'.

Composition Nistil compound of naphthoquinone-1,2-diazide-5-sulfonyl chloride, pyrogallol, and acetone resin 0.75 g (as described in Example 1 of U.S. Pat. No. 3.635.709) Talesol novolac resin 2 .00 g Oil Blue #603 (manufactured by Orient Chemical) 0.04 g ethylene dichloride 16 g 2-methoxyethyl acetate 12 g After exposure for 50 seconds using a 3KW metal halide lamp from a distance,
Silicic acid (IJ) with a molar ratio of SiO□/Na2O of 1.74
The film was developed with a 5.26% aqueous solution of U.M. (pH=12.7).

After developing in this manner, the film was thoroughly washed with water and gummed, and then printed using a conventional procedure. Table 1 shows the results of examining the staining of the non-image area and printing durability at this time. Substrate (E), [
F] and [G] are examples of the present invention, and substrates [A] and [B]
, (C), [D] are comparative examples.

As shown in the results in Table 1, the samples prepared by the manufacturing method of the present invention were superior in stain resistance in non-image areas and had excellent printing durability compared to the comparative example. Furthermore, the method of the present invention was found to be effective in preventing the plate surface from becoming stained even when the plates were left overnight without any treatment.

* Difficulty in staining non-image areas: Transfer stains of ink to non-image areas on printed matter or blankets after printing 1,000 sheets or more were evaluated using the following criteria.

O: There is no stain on the printed matter or the blanket.

O△...The blanket is stained, but the printed matter is not stained.

△...Blanket is dirty and some stains appear on printed matter.

×...The blanket gets dirty and the printed matter gets very dirty.

Claims (1)

[Claims] A support for a lithographic printing plate, characterized in that aluminum hydrate is formed on at least one surface of a grained aluminum plate, the surface is treated with a silicate, and then anodized. How the body is manufactured.