JPS5824189B2 - Method of painting articles with unpainted parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for painting an article whose surface has a portion that must be avoided.

In the case of painted surfaces such as those mentioned above, masking is performed prior to painting in order to hide the unpainted parts.

Masking paper, masking tape, etc. are generally applied as a masking process, but if the unpainted area is small or has a complicated shape, it is difficult and time consuming to apply it.

Another method is to apply a masking agent that forms a film when dry to the unpainted areas, but it is attacked by the heat of the drying oven and the solvent of the paint, making it difficult to peel off after painting is completed.

Furthermore, the above-mentioned masking paper, masking tape, and masking agent in the form of a film must all be peeled off after painting is completed, but this peeling must be done manually, which poses a problem in terms of work efficiency.

As shown in FIG. 1W, when the shape of the article to be coated is complex and the end surface A of the convex portion is left uncoated, it is quite difficult to apply the masking agent, and the masking agent often drips to the side surface.

Therefore, after painting the entire surface of the article, the end faces of the convex parts are polished using a cutting tool or a puff, but this polishing process inevitably leaves some flakes on the edges of the end faces, so it is necessary to remove the flakes. Further work is required.

In view of the above-mentioned points, the present invention provides a coating method that is easy to automate and incorporates masking and removal steps that are easy to process and have excellent safety for articles whose end faces of convex portions are not coated.

As shown in FIG. 1, an article W is set in a concave jig 1 made of an elastic material such as urethane resin, and a core mold 2 also made of an elastic material is stuffed into the recess of the article W. In this way, only the non-painted surface A of the jig 1 is exposed, flush with the surface of the jig 1.

Then, the screen 3 is aligned and stacked on the surface of the jig 1 as shown in FIG. 3, and a masking agent such as polyvinyl alcohol is applied with a roller, blade, brush, or the like.

After the masking agent has dried, the core mold 2 is taken out, the concave jig 1 is removed, and the article W is painted (spraying method or dipping method is possible), and then the masking film is applied, although the paint film is not attacked. The main idea is to remove the masking film by immersing it in a liquid that can dissolve the masking film, thereby revealing the base of the article W in its traces.

In the case of baking paint, the coating is applied while the masking agent is only partially dry, and the baking treatment is carried out before the masking film is eluted.

The masking agent should be chosen to be easily soluble in water, hot water, alcohol aqueous solution, caustic soda aqueous solution, etc., taking into account the non-polluting nature and cost of the removal treatment solution.For example, a masking agent containing 5 to 10% surfactant is selected. Hinyl alcohol is excellent.

This material dries to form a soft film, and it is difficult for paint to adhere to the film.

The melt can be easily removed by soaking it in hot water at around 70℃ for about 10 minutes.

As mentioned above, according to the method of the present invention, the masking treatment before painting and the removal of the masking film after painting are easy.In particular, since the masking film is removed by immersing it in a liquid and dissolving it, it can be easily removed during the automatic painting process. It is effective in completely automating the painting process.

Then, the article W to be painted is exposed only to the non-painted surface A using the concave jig 1 and the core mold 2, and then the masking agent is applied using the screen 3. It can be applied accurately and easily only to the non-painted surface A.

Since the concave jig 1 and the core mold 2 are molded from an elastic material such as urethane resin, some molding errors of the article W to be coated can be absorbed.

In addition, the contact with the screen 3 becomes softer, which also serves to prevent damage to the screen.

[Brief explanation of drawings]

Figure 1 is a perspective view of the article to be coated, L-shaped jig, core mold, and screen. Figure 2 is a perspective view of the jig with the article to be coated and the screen overlaid on it. Figure 3 is a perspective view of the article to be coated. A vertical cross-sectional view of a screen overlaid on a jig. W is the article to be painted, A is its non-painted surface, 1 is the concave jig, 2
is a core type, and 3 is a screen.

Claims (1)

[Claims] 1. An article whose convex end faces must be painted is set in a concave jig made of an elastic material, and a core mold made of an elastic material is stuffed into the concave part of the article, so that only the unpainted surface is left on the surface of the concave jig. Align it to the same level as the jig surface and look through it, overlap the screen on the jig surface, apply a masking agent to the non-painted surface, and after the masking agent dries, remove the concave jig and core mold and paint the item. A method for painting an article having an unpainted part, characterized in that the masking film is removed by immersing it in a liquid that does not attack the paint film but dissolves the masking film, thereby revealing the base material in its traces.