JPH061090A - Manufacture of aluminum supporting body for planographic printing plate - Google Patents

Abstract

PURPOSE:To provide a supporting body wherein it is not necessary to worry about corrosion of process equipments caused by use of acidic aqueous solution, installation of large scale waste water disposal facility and safety of workers, a membrane with a high hardness having abrasion resistance and scratch resistance is provided, and stain and scumming do not occur on non-image parts at offset printing. CONSTITUTION:After a sheet-like or web-like support body consisting of aluminum or aluminum alloy is roughened mechanically, chemically and/or electrochemically, a hydrophilic membrane is formed by physical evaporation. In that case, for the hydrophilic membrane, aluminum oxide membrane is preferable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aluminum support for a lithographic printing plate, and more specifically, it imparts various properties to a roughened aluminum support as a lithographic printing plate. The present invention relates to a method for forming a film for

[0002]

2. Description of the Related Art Lithographic printing is a printing method that utilizes the fact that water and oil do not mix in terms of physical properties, and is a plate surface consisting of a water-receptive non-image area and an ink-receptive image area on one plane. Is formed, and when water is supplied to the plate surface and water is retained in the non-image portion, and ink is further supplied to the plate surface, the ink is retained only in the image portion. Is a technique for printing on paper after transferring it to a blanket. BACKGROUND ART Conventionally, as a photosensitive material for producing a lithographic printing plate used for lithographic printing, there is a so-called "PS plate", which is a plate-shaped support made of aluminum or an aluminum alloy (hereinafter, particularly distinguished description). Is abbreviated as an aluminum support unless necessary) is coated with a photosensitive composition, and the photosensitive plate surface of the PS plate is exposed to a desired image at the time of its use. , The exposed portion is dissolved with water or an organic solvent or a mixture thereof to form a non-image portion, and the non-exposed portion maintains the property of not being dissolved in the above solution, forming an image portion, and in a negative PS plate, The non-exposed portion is dissolved by the solution to form a non-image portion, and the exposed portion maintains the property of not being dissolved in the solution to form an image portion to form a printing plate surface. A. As described above, the non-image portion of the printing plate surface is the portion where the layer of the photosensitive composition is removed, and is therefore the aluminum surface itself of the support. Therefore, the surface of the aluminum support is required to retain water when forming a non-image portion, and therefore the property of retaining water (water retention) is generally improved by roughening or the like. Further, aluminum is a relatively soft material, which is inferior in wear resistance and corrosion resistance, so when it is used as a support for a lithographic printing plate, it is usually subjected to the above-mentioned surface roughening treatment and, if necessary, a solution of an acid or an alkali. And then anodized to form a hard film.

As the method for roughening the surface of the aluminum support, for example, a wire brush graining method, a brush graining method, a sand blasting method, and a ball graining method are used as a mechanical surface roughening method. As a chemical method, an alkali etching method is used, and as an electrochemical surface roughening method, a method of roughening by direct current or alternating current in an aqueous solution of nitric acid, hydrochloric acid and its salt is used. Further, the method of roughening by combining both direct current and alternating current, which is disclosed in JP-A-54-63902, can also be used.

After the surface of the aluminum support is roughened, it is anodized in order to improve the wear resistance and corrosion resistance of the surface as described above. This anodizing treatment has conventionally been performed by anodizing in an aqueous solution of sulfuric acid, phosphoric acid or the like using an aluminum support as an anode and using an alternating or direct current. For example, US Pat. No. 42116.
No. 19 describes an example of forming an anodized film of 0.5 to 10 g / m ^{2 on} the surface of a roughened aluminum support using sulfuric acid as an electrolytic solution. The anodic oxide film formed by using this sulfuric acid as an electrolytic solution is generally an amorphous film, and a relatively thick film can be obtained, but the resistance to alkaline solution is low and the film is corroded when plate making with an alkaline solution as a developing solution. As a result, the abrasion resistance of the surface of the aluminum support is deteriorated, and scumming during printing is likely to occur.
Further, in US Pat. No. 3,511,661, there are 42 to 8
An example of anodic oxidation in a 5% strength phosphoric acid aqueous solution is described. Oxidized layer obtained by anodizing in phosphoric acid aqueous solution is more resistant to alkali than oxide layer obtained by anodizing in sulfuric acid aqueous solution, and it is less likely to cause stain during development. However, it has the drawback of poor resistance to scratches. Roughened aluminum support having an anodized layer obtained by anodizing using the above sulfuric acid or phosphoric acid is desired to further improve the wear resistance and corrosion resistance of the surface. There is.

Further, in order to prevent the non-image area from being contaminated and scummed when the offset printing is performed, conventionally, after the anodizing treatment, the hydrophilic treatment is further required. For this hydrophilic treatment, a method of immersing the roughened aluminum support surface having an anodized layer in an aqueous solution of an alkali metal silicate or 5
It was usual to carry out hydrophilic treatment by a method such as "sealing treatment" in a steam atmosphere of 0 to 300 ° C and 90 Torr or more.

[0006]

However, since an acid such as sulfuric acid or phosphoric acid is used for the anodizing treatment as described above, corrosion of process equipment, necessity of large-scale waste liquid treatment equipment, and work There were problems such as concerns about the safety of workers.

The object of the present invention is to solve the above problems and eliminate the need for concern about corrosion of process equipment due to the use of an acidic aqueous solution, the necessity of large-scale waste liquid treatment equipment, and the safety of workers. A support that imparts a high-hardness film with abrasion resistance and scratch resistance, and does not require additional hydrophilic treatment such as sealing treatment, and that does not stain or stain the non-image area in offset printing. It is to provide a method for producing a support for a lithographic printing plate capable of obtaining

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a sheet-shaped or web-shaped support made of aluminum or an aluminum alloy is mechanically, chemically and / or electrochemically roughened. It has been clarified that the above object can be achieved by a method for producing an aluminum support for a lithographic printing plate, which comprises forming a hydrophilic film by a physical vapor deposition method after chemical conversion treatment. In this case, the hydrophilic film is preferably an aluminum oxide film.

The physical vapor deposition method is PVD (Pyhsical vapor dep).
Oscillation method, which is generally classified into three types: a vacuum deposition method, a sputtering method, and an ion plating method. Among them, the vacuum vapor deposition method includes ordinary vapor deposition method, reactive vapor deposition method, laser vapor deposition method, ion beam vapor deposition method, electron beam vapor deposition method, molecular beam epitaxy (MBE) method,
Electrolytic vapor deposition and the like are included. The sputtering method includes an ordinary sputtering method, a reactive sputtering method, a high frequency sputtering method, a reactive high frequency (RF) sputtering method, a hollow cathode sputtering method, an ion beam sputtering method and the like. The ion plating method includes Mattox method, reactive ion plating method, hollow cathode discharge (HCD) method, reactive HCD method, activated reactive vapor deposition (ARE) method, high frequency ion plating method, cluster ion plating method. , Arc discharge type ion plating method, etc. are included. In the present invention, the method can be appropriately selected from the above methods. In the present invention, a hard film and a hydrophilic film are formed on the roughened aluminum plate by the physical vapor deposition method. Examples of the hydrophilic coating in the present invention include an aluminum oxide coating, a silicon oxide coating, a titanium oxide coating, and the like, and the hydrophilic coating is not limited to these. Among these, the aluminum oxide film is most preferable. The thickness of the hydrophilic film to be formed is generally 10 μm or less, but it is preferably 2 μm or less in terms of performance as a lithographic printing plate support. With the support having a hydrophilic film obtained by this physical vapor deposition method, scratch resistance and printing durability are good in offset printing without conventional anodizing treatment and additional hydrophilic treatment, and further non-image It is possible to obtain a printing plate which is free from stains and scumming of parts.

Aluminum plates used in the present invention include pure aluminum and aluminum alloy plates. Various aluminum alloys can be used, and for example, aluminum alloys with metals such as silicon, iron, copper, manganese, magnesium, chromium, zinc, bismuth, and nickel are used. The aluminum plate may be in the form of a sheet or a web, and it is also possible to use a laminate of paper, plastic, or other metal with the surface of the aluminum being aluminum in view of the constitution of the material. The aluminum plate should not cause a dimensional change when it is mounted on a printing machine as a printing plate. For example, a plate made of aluminum alone generally has a thickness of 0.1 to 0.5 mm. What is used.

The surface of the aluminum plate may be subjected to a degreasing treatment for removing rolling oil on the surface, if necessary, prior to the roughening treatment. The surface of the aluminum plate is roughened in order to improve water retention and adhesion with a layer of a photosensitive material coated thereon. As the surface roughening method, the above-mentioned method, that is, the mechanical surface roughening method, the chemical surface roughening method, the electrochemical surface roughening method, or a combination thereof can be used. The thus roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment, if necessary. When the electrochemical surface roughening method is used, it is usual to carry out desmutting treatment with phosphoric acid, sulfuric acid, chromic acid, etc., if necessary.

A hydrophilizing film is formed on the roughened aluminum plate by the physical vapor deposition method described above. In the present invention, thereafter, the conventional anodic oxidation treatment and additional hydrophilic treatment are not required. However, of course, such hydrophilic treatment may be performed. This additional hydrophilizing treatment is carried out by dipping in an aqueous solution of an alkali metal silicate, for example, sodium silicate, as described in US Pat. Nos. 2,714,066 and 3,181,461. Under hydrophilic cellulose (eg, carboxymethyl cellulose, etc.) containing a water soluble metal salt (eg, zinc acetate, etc.) as described in US Pat. No. 3,860,426. A coating layer can also be provided. The PS plate (Pre-sensing plate) was placed on the support for lithographic printing plate thus obtained.
A photosensitive layer that is conventionally known as a photosensitive layer (abbreviated as itized Plate) can be provided to obtain a photosensitive lithographic printing plate.

The photosensitive composition for these photosensitive layers includes
For example, (1) a diazo compound represented by a condensate of p-diazophenylamine and paraformaldehyde, which is soluble in a water-soluble or water-insoluble organic solvent, preferably a water-insoluble organic solvent is used. Examples of preferable diazo compounds include fluorocaprylate and 5-nitroorthotoluenesulfonate, which are condensates of p-diazodiphenylamine and paraformaldehyde. Such a diazo compound is used alone to prepare a resist, but is also used with a binder such as a shellac or a copolymer compound containing hydroxyethyl acrylate. (2) o
-Quinonediazide compounds, particularly preferably o-naphthoquinonediazidesulfonic acid ester, o-naphthoquinonediazidecarboxylic acid ester, o-naphthoquinonediazidesulfonic acid amide and the like are used. Such o-
The quinonediazide compound is used alone in the preparation of a resist, but it is used as a mixture with an alkali-soluble resin such as a novolac type phenol resin. (3) A photosensitive azide compound, for example, an aromatic azide compound in which an azide group is bonded to an aromatic ring directly or through a carbonyl group or a sulfonyl group. Preferred aromatic azide compounds are compounds containing one or more groups such as azidophenyl, azidostyryl, azidobenzal and azidocinnamoyl. These photosensitive azide compounds are also used together with the binder. A preferable binder is an alkali-soluble resin (for example, a novolac type phenol resin or a vinyl copolymer containing polyacrylic acid). (4)
Polymeric compounds containing cinnamic acid groups, eg US Pat. No. 3,0
30,208, 3,707,373 and 3,4
Photosensitive resin containing as a main component a photosensitive resin composed of a (2-propylidene) malonic acid compound such as cinnamylidene malonic acid and a bifunctional glycol compound as described in each specification of No. 53,237. Etc. are mentioned as a suitable photosensitive composition. An excellent lithographic printing plate can be prepared by coating these photosensitive compositions, if necessary, with a thermal polymerization inhibitor, a plasticizer and a pigment on the aluminum support according to the above-mentioned production method of the present invention.

[0014]

【Example】

(Example-1) The surface of a JIS 1050 aluminum sheet was grained with a rotating nylon brush using a Pumisu water suspension as an abrasive. At this time, the surface roughness (centerline average roughness) was 0.5 μm. 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 surface dissolved was 5 g / m ² . After washing with water, soak in 30% nitric acid aqueous solution for 1 minute, and
Voltage 23% at anode and 12V at cathode
By using a rectangular alternating wave of (Japanese Unexamined Patent Publication No. 52-77702).
(Current waveforms described in the examples of the publication), electrolytic etching is carried out at an anode-time electric quantity of 160 coulomb / dm ² .
It was immersed in a solution of 30% sulfuric acid at 50 ° C. for desmutting and then washed with water. Next, by irradiating a CO ₂ laser on the aluminum plate which has been roughened in a vacuum to oxidize the aluminum oxide film on the roughened aluminum plate, an aluminum substrate (A) is obtained.
Got Laser power is 70W, vacuum degree is 1 during processing
0 ^-4 Torr, aluminum substrate temperature was 250 ° C., the thickness of the aluminum oxide film was 1 [mu] m.

Example 2 An aluminum oxide film was formed on the aluminum plate subjected to the same surface roughening treatment as in Example 1 by a sputtering method in an Ar + O ₂ gas atmosphere to form an aluminum substrate (B). Obtained. The gas pressure was 10 ^-2 Torr and the thickness of the aluminum oxide film was 1 μm.

Comparative Example-1 The same roughened aluminum plate as in Example-1 was treated with an aqueous sulfuric acid solution (concentration: 150 g /
Anodized film in an aluminum substrate (C).
Got An anodized film was formed to obtain an aluminum substrate (C). Current density of 2 A / dm ^{2 for} anodizing treatment
The thickness of the anodized film was 1 μm using a direct current of

Next, the coating amount after drying the following photosensitive solution is
Each of the aluminum substrates (A), (B), and (C) was coated so as to have a concentration of 2.5 g / m ^2, and a photosensitive layer was provided to prepare a lithographic printing plate. (Photosensitive solution) Esters of naphthoquinone-1,2-diazide-5-sulfonyl chloride and pyrogallol-acetone resin (described in Example 1 in the specification of US Pat. No. 3,635,709). ) 0.90 g cresol novolac resin 2.00 g phthalic anhydride 0.20 g 2- (p-butoxyphenyl) -4,6-bis (trichloromethyl-S-triazine 0.02 g oil-soluble dye (C142595) 0.03 g Ethylene chloride 15 g Methyl cellosolve 12 g The PS plate thus prepared was exposed through a transparent positive film in a vacuum frame from a distance of 1 m by a metal halide lamp of 3 kw for 50 seconds, and then SiO.
Development was performed with a 5.26% aqueous solution of sodium silicate (pH = 12.7) having a molar ratio of ₂ / Na ₂ O of 1.74. After the development as described above, the contamination degree and scratch resistance of the non-image area were examined. The printing durability of the offset printing machine was also examined. Evaluation method for non-image area contamination Judgment is made by the difference between the reflection optical density of the non-image area and the reflection optical density of the support surface immediately before coating the photosensitive layer. Evaluation method of scratch resistance Judgment was made based on the degree of the surface of the non-image portion after the non-image portion was reciprocated 350 times with alumina polishing paper using a Suga test machine abrasion tester (NUS-ISO-1 type). The results are shown in Table 1.

[0018]

[Table 1]

[0019]

Effects of the Invention According to the method for producing a lithographic printing plate aluminum support of the present invention, (1) a lithographic printing plate support having improved scratch resistance and printing durability can be obtained. (2) A lithographic printing plate support with improved non-image area contamination and background stains can be obtained without the need for additional hydrophilic treatment. (3) Corrosion of process equipment due to anodizing treatment, necessity of large-scale waste liquid treatment equipment, support for lithographic printing plate excellent in performance without using an acidic aqueous solution which is concerned about safety of workers can get.

Claims (2)

[Claims] 1. A sheet-shaped or web-shaped support made of aluminum or an aluminum alloy is mechanically, chemically and / or electrochemically roughened, and then a hydrophilic film is formed thereon by physical vapor deposition. A method for producing an aluminum support for a lithographic printing plate, which comprises forming the aluminum support. 2. The method for producing an aluminum support for a lithographic printing plate according to claim 1, wherein the hydrophilic film is an aluminum oxide film.