JPS5912757B2 - Aluminum partial coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, as a method for painting patterned recesses provided on the surface of a metal plate, as shown in FIG. Concave part b in etc.
After forming the paint c, the paint c is poured into the recesses b, or the entire surface is painted and then the paint on the convex parts d is removed.
Alternatively, the process of removing the paint takes a long time and requires skill, resulting in poor productivity and a high rate of product failure.

Moreover, if the depth of the recess is shallow or the area is wide,
There is a drawback that partial painting is not possible or a desired coating cannot be obtained. The present invention eliminates the drawbacks of such conventional methods and forms an anodized film on the entire surface of an aluminum material easily and accurately without requiring any skill, yet forming a partially coated area protected from external contact. Then, after sealing the pores to form a non-conductive oxide film, the non-conductive oxide film is partially removed using an etching solution according to the pattern, and a predetermined depth of 10 mm is placed in the removed recess. The method is characterized in that the metal base is exposed and then electrodeposition coating is applied to the metal base within the recessed portion by electrophoresis. Next, embodiments of the present invention will be described in detail.

First, an aluminum material, for example, a plate-shaped keliminium, is immersed in an electrolytic solution and anodized on the entire surface to form an anodized film, and then a so-called sealing process is performed to transform the oxide film into a non-conductive oxide film. Apply until.

The pore sealing treatment is carried out by a conventional method, for example, using boiling water using a pore sealant containing cobalt acetate or the like or steam pressure. After that, for example, a photosensitive chemical-resistant resin is applied to the entire upper surface of the oxide film, a predetermined pattern is printed on it by photosensitization, and the unexposed areas are then dissolved and removed with a solvent to achieve the predetermined oxidation. Expose the film part. Next, add this to 25
The exposed oxide film is dissolved and removed using an etching solution, for example, an alkaline solution such as caustic soda, and the aluminum surface is exposed in the removed recess. Instead of the above-mentioned photosensitive method, for example, a predetermined pattern is partially printed on the upper surface of the entire 30 oxide film using a chemical-resistant ink using a screen process method, and the oxide film portions that are not exposed by the ink are printed as described above. The aluminum base is then dissolved and removed using an alkaline solution, and the aluminum surface is exposed on the bottom surface of the recess that has been removed. If this alkaline solution immersion is carried out for a desired long time, the exposed 35 aluminum surface can be corroded and a deep concave aluminum surface can be formed on the metal plate surface. After performing such alkali immersion treatment, the protective film remaining on the entire surface as shown in Table 3, ie, the photosensitive film or chemical-resistant ink, is removed by immersion in a nitric acid aqueous solution or the like, and then washed with water.

In this way, an aluminum plate 1 is obtained as shown in FIG. 2, the surface of which is partially comprised of a non-conductive oxide film 1a and a partially conductive metal surface 1b having a predetermined pattern. .

The metal background surface 1b of each pattern is preferably a concave etched surface clearly formed with an appropriate depth 2 as shown in FIG. 3, and generally, as shown in FIG. As shown in FIG. A processed product with concave portions on the surface of the metal plate is obtained.As shown below, the aluminum plate 1, which has been partially formed with a non-conductive and conductive surface, is electrodeposited by electrophoresis. One example of its implementation is as follows: After the aluminum plate is sufficiently washed with water, it is inserted into an electrodeposition tank in which a water-soluble acrylic resin paint has been dissolved, and this is connected to an anode. Direct current 10 between the cathode plate in the tank
Apply 0 to 200 V and immerse for 1 to 2 minutes at a bath temperature of 20 to 30°C.

After that, take it out, wash off the excess paint with water, and bake it to dry. In this electrodeposition process, the charged paint particles in the bath migrate and adhere only to the metal surface recesses 1b, which are made up of conductive patterns of a predetermined shape, on the surface of the aluminum plate 1, and the non-conductive oxide film Since it does not adhere to the part 1a at all, a partially coated product as shown in Figs. 5 and 6 is obtained in which the electrodeposited coating 3 is automatically deposited on the pattern recessed part 1b exactly in accordance with the surface of the metal pattern. I can't stand it. Thus,
Since the present invention is such a partial electrodeposition coating, it is understood that accurate partial coating can be obtained even if the recess 1b is deep, has a large area, or has a deformed surface such as a curved surface. be done. Further, since the electrodeposition coating time is usually about 1 to 2 minutes, a predetermined partial coating can be obtained in an extremely short period of time. Since this electrodeposition coating 3 is applied inside the recess 1b, the surface of the aluminum, that is, the oxide film 1
It shall not protrude outward from the a side, and will be protected from damage and peeling due to contact from the outside. As described above, according to the present invention, an anodized film is formed on the surface of aluminum, and then a sealing treatment is applied to this to form a non-conductive oxide film, and then the non-conductive oxide film is partially patterned. Accordingly, since it is removed with an etching liquid, the metal base of a predetermined concavity is exposed in the removal recess, and then electrodeposition coating is applied to the metal base within the recess by electrophoresis. , Electrodeposition coating of a predetermined shape is automatically and accurately obtained in the recess according to the pattern of the metal background, and the electrodeposition coating does not protrude from the surface of the aluminum oxide film, so it is similar to electrodeposition coating on the surface. It has the effect of providing a good partially electrodeposited product that is free from external contact and damage.

[Brief explanation of drawings]

Figure 1 is a perspective view of a partially painted product by the conventional method, Figure 2 is a perspective view of a product treated by this method after etching, Figure 3 is a cross-sectional view taken along the - line in Figure 2, and Figure 4 is another example. 5 is a cross-sectional view of the third
6 shows an enlarged sectional view of a part of the product corresponding to FIG. 4. FIG. 1... Aluminum plate, 1a... Oxide film part, 1b... Metal skin part, 2...
Depth, 3...Electrodeposition coating.

Claims (1)

[Claims] 1 An anodized film is formed on the entire surface of the aluminum material, and then a sealing treatment is applied to this to make it a non-conductive oxide film, and then the non-conductive oxide film is partially removed using an etching solution according to the pattern. A partial coating method for aluminum, characterized in that a metal base of a predetermined depth is exposed in the removed recess, and then electrodeposition coating is applied to the metal base in the recess by electrophoresis.