JPH0474067B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for improving the appearance of resin molded products.

[Problems to be solved by the conventional technology/invention] Welds and uneven gloss (hereinafter also collectively referred to as appearance defects) generally occur in resin molded products. This occurs in areas where fluid resins flow from different directions and collide with each other in the mold during molding, and often occurs in resin molded products with complex shapes such as lattice shapes.

In particular, this appearance defect becomes a problem in the case of resin molded products used as automobile bumpers as shown in FIG. That is, in the resin molded product, in order to improve the design, the color of the grid portion 1 provided at the top and front part of the bumper is set to black, etc.
The color of the bumper part 2 is often the same color as the car body or a different color from both the lattice part 1 and the body. Therefore, after molding a molded product using resin colored black etc., only the bumper part 2 is colored. Generally, a method is adopted in which the grid portion 1 is left as an unpainted portion by painting. In that case, the resin molded product should be painted as a pre-treatment for partial painting of only the bumper part 2.
This is done in the process of applying TCE (trichlorethylene) steam cleaning to the entire molded product, masking the lattice part 1, and then applying a top coat to the bumper. A problem often arises in that many appearance defects become even more noticeable.

Therefore, it is conceivable to apply colored coating to the lattice portions to improve the appearance defects, but in that case, it is necessary to mask the bumper portions, which have a large surface area, resulting in the problem of complicating the process.

The present invention has been made as a result of repeated research in view of the above-mentioned points, and an object of the present invention is to provide a method for improving the appearance of a resin molded product that does not require masking around a portion that requires improvement in appearance.

[Means for Solving the Problems] The present invention provides a method for painting a resin bumper, in which a colored resin is molded and then colored coating is applied to a part of the bumper, leaving an unpainted part of the bumper. Appearance of a resin bumper having a part with a complicated shape such as a lattice part, wherein the colored part is applied to the bumper with the part being an unpainted part, and then a clear coating is applied to the unpainted part. Regarding improvement methods.

[Example] Hereinafter, the method of the present invention will be explained by taking as an example a resin molded product for a bumper used in an automobile, etc., as shown in FIG.

In FIG. 1, a resin molded product 3 is an integrally molded product consisting of a lattice portion 1 and a bumper portion 2, and is used as a bumper for an automobile. Such a resin molded article 3 is produced using a colored resin such as a polypropylene resin, a polybutylene terephthalate resin, a polycarbonate resin, or the like to which a pigment such as black is added. The obtained resin molded product 3 in black or other colors is entirely subjected to TCE steam cleaning as a pretreatment for painting the bumper part 2, and then the grid part 1 is masked, and then the bumper part 2 is subjected to primer painting, top coating, and baking. The masking of the grating portion 1 is removed. In this state, appearance defects such as welds and uneven gloss remain on the surface of the lattice portion 1. Therefore, if you apply clear coating to the grid part 1,
The appearance defects can be made less noticeable.

As the paint for clear coating used in the present invention,
There are no particular restrictions as long as it is a clear coating for resin.
For example, urethane resin clear coating (for example, Olefix P1000 (product name, manufactured by Asahipen Co., Ltd.))
etc. can be mentioned.

In addition, there are no particular restrictions on the method and thickness of the clear coating, and for example, the coating thickness after drying may be 5 to 30 μm using a method such as air spraying.
It can be done to a certain extent.

The clear coating can be performed without masking the bumper portion 2, and even if some of the clear coating paint adheres to the bumper portion 2, no appearance defects will occur.

As described above, according to the method of the present invention, appearance defects can be made less noticeable by clear coating, and unnecessary labor such as masking, which complicates the process, can be prevented.

[Effects of the Invention] According to the method of the present invention, by applying a clear coating, it is possible to improve the appearance of a resin molded product without masking the area around the area where appearance defects need to be improved. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a resin molded product to which the method of the present invention is applied. Reference numbers in the drawings: 1... Lattice part, 2... Bumper part, 3... Resin molded product.

Claims (1)

[Scope of Claims] 1. A resin bumper coating method in which a colored resin is molded and then a colored coating is applied to a part and an unpainted part is left, wherein the bumper has a complex structure such as a lattice part. 1. A method for improving the appearance of a resin bumper, which has a shaped part, and the bumper is coated with the colored paint while the part is treated as an unpainted part, and then a clear coat is applied to the unpainted part.