JPH0819533B2 - Method for manufacturing aluminum coating material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum or aluminum alloy (hereinafter simply referred to as "aluminum") coating material for forming which has been subjected to a base treatment. More specifically, the present invention relates to a method for producing an aluminum coating material that is used for producing an aluminum cap or the like and is suitable for forming such as drawing or punching.

[0002]

^2. Description of the Related Art Conventionally, aluminum coating materials for forming and processing have been manufactured by applying a size coat of ² to 7 g / m ² to a degreased aluminum base plate and then applying a clear varnish or the like. After adding a film (top coat), it was often commercialized as an aluminum cap or the like by a cap forming drawing process. In this case, the purpose of applying the size coat is to prevent the coating film formed by coating on the size coat from becoming brittle during the molding process, resulting in the peeling of the coating film. However, since this size coating method requires baking in an oven, it is a disadvantageous method in terms of cost and productivity as compared with chemical conversion treatment.

As the size coat for the molding process, a modified vinyl type resin, an epoxy ester type resin or a vinyl chloride type vinyl acetate type resin is used so as to withstand severe deformation processing conditions such as molding drawing. However, the adhesion between the aluminum base plate and the topcoat coating film is not always perfect at present.

[0004] On the other hand, the problems of the peeling of the top coat due to the severe drawing process have not been solved in the phosphoric acid chromate treatment and the undercoat treatment for forming a zirconium-containing polymer film which are currently in practical use. Therefore, an object of the present invention is to improve the adhesion between the aluminum base plate and the topcoat coating film by chemical conversion treatment without using a conventional size coat which is a base treatment having disadvantages in terms of cost and productivity. An object of the present invention is to provide a method for manufacturing an aluminum coating material which is strong and does not cause peeling of the top coat during forming and drawing.

[0005]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned objects, the inventors of the present invention applied a combination of a phosphoric acid chromate treatment and a zirconium-containing chemical conversion treatment as an undercoat treatment to an aluminum base plate. By forming a film, it was found that the adhesion strength of the topcoat coating film at the time of forming and drawing can be greatly improved and peeling can be completely prevented, and the present invention has been completed.

That is, according to the present invention, (1) the surface of an aluminum material is treated with chromium as a base treatment.
After chemical conversion treatment with liquid, chemical conversion treatment with zirconium-containing liquid
The feature is that the coating is applied to form a film.
A method of manufacturing an aluminum coating material, and (2) continuous processing of coil foam
The manufacturing method according to (1) is provided.

The underlying film formed in the present invention contains a predetermined amount of chromium ions. An example of such a film is a phosphoric acid chromate film, which can be obtained by degreasing an aluminum material, washing it with water, treating it with a commercially available phosphoric acid chromate treating agent, forming it on the surface, and drying it. In this case, the amount of chromium ions attached to the film is 3
If it is less than mg / m ² , a uniform surface film may not be obtained and the adhesion may be uneven. Also, when the amount of chromium ions increases, the adhesion of the coating film improves, but if it becomes too large, the coating hardens, the coating cracks during molding, and the adhesiveness deteriorates. It also causes deterioration. Therefore, it is preferable not to exceed 100 mg / m ² .

Next, in the present invention, a predetermined amount of zirconium ions is contained in the undercoat. The zirconium-containing base coating, separately from the chromium-containing primer film, is formed on top of it. The zirconium coating is generally formed using water soluble compounds such as ammonium zirconium carbonate and alkali metal or ammonium salts of fluorozirconates. Examples of the zirconium-containing polymer containing a carboxyl group include polyacrylic acid, polyvinyl alcohol, hydroxy ether of cellulose, maleic anhydride of ethylene and zirconium salt of polyvinyl pyrrolidine and polyvinyl methyl ether, and zirconium in a dispersed particle type polymer. There are also acrylic copolymer latices containing. This polymer is applied to the surface of an aluminum material in a state of being dissolved in an aqueous solvent,
After that, it is dried by a heating device such as an oven. When such a zirconium-containing undercoat is applied to a chromium-containing undercoat, it can be dipped into the porous film structure found in the dry film of the previously treated chromate film and penetrate into the aluminum base plate.

The zirconium ions thus permeated into the chromate film are then dried to embed the porous part of the chromate film with, for example, a film of zirconium polymer to strengthen the film itself and to form an aluminum base plate. It increases the coating adhesion. Here, the zirconium content in the coating is 0.5
It is desirable that the amount is 50 mg / m ² or more and 50 mg / m ² or less. If it is less than 0.5 mg / m ² , the porous portion of the chromate film cannot be sufficiently filled, and therefore it is an addition. Further, if it exceeds 50 mg / m ² , the zirconium film becomes too thick, and the film is cracked during molding and the effect is weakened.

The total amount of chromium and zirconium is 4 to
130 mg / m ² is preferred. If it is less than 4 mg / m ² , the coating on the aluminum surface will be non-uniform, and if it exceeds 130 mg / m ² , the coating will be thick and the drawing ratio during molding will decrease. Therefore, when the total amount of chromium and zirconium is within the above range, the coating becomes insoluble in water or solvent, and thus excellent corrosion resistance and coating adhesion as a base treatment can be improved.

After forming a film by such a base treatment, a top coat is formed thereon by a usual method. The aluminum coating material treated as described above is characterized in that it is continuous in coil form.What kind of application is used for processing such as tearing and redrawing as well as forming and drawing of caps etc. Can also be applied to. The aluminum coating material obtained in this way is
It has good surface slipperiness, excellent corrosion resistance, good heat resistance, and can prevent slip scratches in the subsequent top varnish process. In addition, even if it is printed directly on an aluminum plate, ink adheres. It also has the characteristic that it has good properties.

[0012]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Example Using an aluminum material for a cap as a treatment target, treatment was performed under the following conditions, and then coating was performed. First, aluminum material for caps (JIS A1100P-H
No. 24, thickness 0.25 mm) was spray degreased with 2% Rydrin 322 (manufactured by Nippon Paint), then washed with water and dried. Then, it was immersed in a mixed bath of Alodin 401-45 (chromium phosphate solution, manufactured by Nippon Paint Co., Ltd., formulation B) at 30 ° C., followed by washing with water and drying to form a porous chromate film on the surface of the aluminum material. Furthermore, 10 g of polyacrylic acid and 60 g of ammonium zirconium carbonate were added to 1 liter of water and stirred and diluted, and a solution (formulation C) was applied onto the phosphoric acid chromate film with a roll coater at a temperature of 25 ° C. and dried at 220 ° C. for 10 seconds. Then, a chemical conversion treatment as a base treatment was performed. The above steps were carried out by a continuous method using an aluminum material of coil form.

The sample having the film thus formed was coated as follows, and the following two items were tested. This is Experiment No.1.

(1) Coating Test 1 (Peeling Strength) The aluminum material manufactured according to the above procedure was cut into a rectangle (thickness 0.25 mm × width 10 mm × length 50 mm) and epoxyphenol was applied to the surface subjected to the chemical conversion treatment. Two sheets of the resin-based paint were prepared, two coated surfaces were faced to each other, a polyamide hot-melt film was sandwiched between them, and heat-treated at 250 ° C. for 10 minutes, and then the T-type peel strength was measured. For comparison, conventional size coat (Kansai Paint, XJ-C119F, 180 ° C x 10 minutes baking)
Sample (Experiment No. 2, formulation A), sample only subjected to phosphoric acid chromate treatment (Experiment No. 3, formulation B), and sample subjected to chemical conversion treatment of only zirconium-containing acrylic acid polymer (experimental) No. 4, formulation C) were prepared, and their T-type peel strengths were also measured in the same manner as above. The results are shown in Table 1.

(2) Coating test 2 (presence or absence of peeling of the top coat after cap molding) For an aluminum material subjected to the above-mentioned base treatment (base treatment materials having the prescriptions of the base treatment materials 1 to 4 shown in Table 1). A top coat (manufactured by Kansai Paint Co., Ltd., 58-L344, epoxy phenolic resin, baked at 190 ° C. for 10 minutes) was applied, and a cap was formed with a drawing ratio of 2.0 (punch system 33 mmφ, blank system 66 mmφ). The presence or absence of peeling of the cap side surface of the cap, which was subjected to the most severe forming and drawing process, was visually judged, and the results are shown in Table 1.

From Table 1, the conventional size coat (Experiment No.
2), chromate phosphate alone treatment (Experiment No. 3), and zirconium-containing polymer alone treatment (Experiment No. 4), compared with the conventional aluminum surface treatment methods, the aluminum coating material of the present invention (Experiment No. 1) Has a high T-type peel strength, and no peeling of the topcoat is seen after cap molding.

[0017]

[Table 1]

[0018]

The aluminum coating material obtained by the production method of the present invention has a coating adhesion between an aluminum substrate and a topcoat which is significantly higher than that of conventional aluminum chromate or zirconium salt alone treatment. It is improved and can effectively prevent the peeling of the topcoat coating film after drawing after forming, and has industrially remarkable effects, and has a great industrial utility value. In addition, according to the method for producing an aluminum coating material of the present invention, the adhesion of the coating film is extremely excellent without using a size coat, which is problematic in terms of productivity and production cost. An aluminum coated plate can be obtained.
Further, according to the method of the present invention, the continuous chemical conversion treatment of the aluminum material of the coil foam can be performed.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C23C 22/56

Claims (2)

[Claims] 1. Aluminum or aluminum as a base treatment
The surface of the aluminum alloy material was subjected to chemical conversion treatment with a chromium-containing liquid.
Then, chemical conversion treatment with a zirconium-containing liquid to form a film,
Aluminum characterized by painting on it or
Manufacturing method of aluminum alloy coating material. 2. A continuous process of coil form.
The manufacturing method according to claim 1, wherein: