JPS5855503A - Aluminum coated steel plate for printing plate - Google Patents

Abstract

PURPOSE:To obtain the titled steel plate which can be used as a substitute of an Al plate, is inexpensive and can attain to conserve material resources and energy, by coating an Al film on the surface of a steel plate at a specific thickness by a powder coating method. CONSTITUTION:An Al film is coated on one surface or both surfaces of a steel plate at a thickness of 15-100mum by a powder coating method to obtain an Al coated steel plate for a printing plate. As the powder coating method, either one of methods, that is, a method an Al powder is adhered to the steel plate by an electrophoretic method or a method wherein the dried Al powder is coated on the surface of the steel plate which is preliminarily plated with iron and adhered under pressure and heating, is employed. By this method, the Al film which is free from pinholes and can assure close adhesiveness required in reuse due to re-polishing can be obtained. When the thicknss of this Al film is the lower limit or less, a large amount of pinholes are formed and, when exceeds the upper limit or more, the close adhesiveness is slightly lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum-coated steel plate that can be used as a substitute for the aluminum plate conventionally used as a plate material for lithographic printing.

The process of making a lithographic plate consists of two steps: pre-treatment of the plate surface, application of a photosensitive liquid, printing, development, and post-treatment of the plate surface, and the 28th plate (the plate that has been given photosensitivity) is pretreated by the photosensitive material manufacturer in advance. A photosensitive liquid coating process was carried out, but among these steps, the plate surface pretreatment increased the @7ft area of the photosensitive film.
The purpose of this treatment is to strengthen the printing durability of the image area of the printing plate and improve the water retention of the non-1aii area, and currently the most effective anodizing treatment is usually performed.

Zinc or aluminum was used as the material for planography and 28 plates, but aluminum has poor lipophilicity and high hydrophilicity compared to zinc, so sharp lines can be obtained, and due to the difference in specific gravity and low cost, Currently, Al i=tsu^ is mainly used. However, due to recent resource conservation, energy conservation, and the rapid rise in the price of non-ferrous metals,
There has been an increasing demand to reduce the price while guaranteeing the same surface quality as the five-plate printing plate, and for example, used printing plates are being polished and recycled two or three times. Demand for further price reductions is becoming increasingly strong.

The present invention is intended to meet these demands, and is characterized by applying pure alunnicum or aluminum alloy to one or both sides of a steel plate (in the case of both sides, with the same or different thickness) using a powder method. When the coating thickness is 15 to 100M and the film thickness is 20μ or more, it is preferable to pre-plate the steel plate with zinc.Aluminum obtained in this way Coated steel sheets not only have a low cost per unit area, but are also effective in saving resources and energy.Furthermore, the surface quality is free of pinholes, and the adhesion of the aluminum film is extremely good, making it comparable to aluminum sheets. Therefore, the above-mentioned anodic oxidation as a plate surface pretreatment can be performed extremely effectively, and since the base material is a steel plate that has high strength and can be used with magnets, it is easy to perform reprocessing work by polishing. Film thickness up to 100〇
This has the advantage that the number of times of polishing can be increased from 1 to 2 times with conventional Al and Aluminum alloy coating 〇Generally known methods for producing aluminum coated steel sheets include the melting method, organic aluminum vapor phase decomposition method, vacuum evaporation method, and cladding method. However, the melting method has the problem of pinholes or surface smoothness due to the wave pattern at the interface, the vapor phase method and vacuum evaporation method have the problem of thin film thickness and high manufacturing cost, and the clad method also has the same problem. However, the problem of high cost remains, and there are many problems that need to be solved in order to apply the present invention.

In the present invention, a powder method is used instead of these methods. This is because it is easy to eliminate pinholes in the aluminum film, and it is possible to use an ultra-thick pure aluminum or aluminum alloy film as thick as 100 mm. The thickness guarantees the adhesion of the aluminum film and can be easily and inexpensively obtained, pure Al2-U or aluminum alloy can be easily coated, and there is a hard and brittle alloy layer at the interface between the steel plate and aluminum. This is due to the fact that it does not require any production and therefore has very good workability.

As an aluminum coating method using this powder method,
A method in which aluminum powder is applied to a steel plate by electrophoresis, then crimped and heated; A method in which dry aluminum powder is applied to the surface of a steel plate pre-plated with iron, crimped and heated; Inhibitor for aluminum and iron or iron At the same time, a water slurry of powdered aluminum is applied, dried, compressed, and heated, or aluminum or aluminum alloy is coated on the surface of the steel plate, which has been previously electroplated with zinc to a thickness of 0.01 to 0.3S. There are known methods in which powder is applied and then heated, rolled, reheated, or rolled, heated, rolled, and reheated.

Aluminum-coated steel sheet for printing plate making according to the present invention: /) The manufacturing method may be any of the above methods, but the important thing is that the surface quality of the aluminum-coated steel sheet obtained by such a method is the same as that of an aluminum plate, and there are no pinholes. There is no such thing, and the extremely thick coating increases the number of reuses due to re-polishing. For this purpose, it is necessary to be able to provide an extremely thick coating that guarantees aluminum M adhesion. Other than the method of pre-coating the steel plate with zinc, the limit aluminum thickness that guarantees the adhesion of the aluminum film is at most 25111@l, and if the thickness is greater than this, the method of pre-coating the steel plate with zinc is preferable. 0 The reason for this is that when the plate material is attached to the printing press cylinder, both ends of the plate are bent at an acute angle and fixed, and it is important that no cracks occur in the aluminum film at this time. To prevent this, the thickness of the aluminum film should be 20 or more, especially 25. It is necessary to pre-coat with zinc if the coating thickness is at least 15-1 and the maximum thickness is preferably adjusted to 100/ill.

This is because when the aluminum thickness is less than 15 pkm, there are many pinholes, and when it is more than ioom, the aluminum film adhesion is slightly reduced.

Hereinafter, the aluminum-coated steel plate for printing plate making of the present invention will be specifically explained with reference to examples. ,
Electrochemically plated with 0.057 m of zinc under the conditions of pickling (Kit, room temperature, 10 seconds immersion) and water washing followed by plating solution: zinc sulfate 240 f/l, chloride y-v-
= Rim l 5 fil Al2 sulfate 30 f/l, sodium acetate 15 f/j Licorice 1 f/1% pH 4, temperature 30°C Current density: 3 A/dj Aluminum powder suspended on this zinc pre-coated steel plate A liquid (a liquid in which 8 f of aluminum powder of 10 fK320 mesh or less of distilled water was suspended) was coated with a roll coater. This was dried at 150°C for 10 minutes, then 4
After heating to 50° C. for 2 minutes, rolling was performed by 5% using a rolling mill. Finally, final heating was performed at 550° C. for 10 seconds. The aluminum coating thickness of the obtained steel plate was 30, 55, 70.94
It was a lie. These have no bulges at all, and have good bending workability, even down to the close contact surface. PSM+ was manufactured using these aluminum plated steel plates and 8 aluminum plates (plate thickness 0.25 mm) as comparative materials. All substrates were first degreased with alkaline, polished with permiston polishing agent, washed with water, desmutted with Sakaki OH in step 5, and then
% nitric acid and then anodized (3-target) with a voltage of 70 V in a bath containing 11 um of 5×NaOH phosphate. Next, a conventionally known photosensitive liquid was applied using a roll coater and dried to produce 28 plates.

After each of these plates was exposed, they were developed with a toe developer, and 50,000 copies were printed using each plate. All have printing durability, water retention,
It was also good in #note resistance. Next, the aluminum on the surface was removed by 8-fine polishing for recycling treatment, and anodized again using the same method as described above (3-28 plates were produced after the target was removed, and 50,000 plates were stamped after exposure and development. It was confirmed that all of them had good printing durability, water retention, and rust resistance.

The results of repeating this operation and checking the possible number of playbacks are shown in Table 1 below.

For powder method aluminized steel sheets, the number of recycles increased in proportion to the aluminum coating thickness, and at 30-μm, the number of recycles was 1, but at 55 μm thick, it was 3 times, and at 70 μm thick, it was 5 times.
It was possible to regenerate eight times at 941k1m. On the other hand,
The aluminum plate used as a comparative material was tested 2 to 3 times. This is because aluminum is soft and easily scratched during the recycling process, and shape defects are likely to occur. In this respect, aluminum-plated steel plates that use steel plates as the base material are endowed with strength, so
There were no shape defects such as bends, and since magnets could be used, the recycling process was much easier than with aluminum plates.

Patent applicant: Kawasaki Steel Corporation

Claims (1)

[Scope of Claims] (An aluminum coated steel plate for printing plate making, characterized in that one or both sides of the steel plate is coated with an aluminum film with a thickness of 15 to 100 mm by a 1' powder method. ■ The Al 2= The aluminum-coated steel plate for printing plate making according to claim 1, wherein the steel plate is pre-galvanized before being coated with aluminum when the thickness is 20 mm or more.