JPS60255174A - Multicolor painting method - Google Patents

Abstract

PURPOSE:To improve the finished appearance of the overcoat film at a dusted part by coating a solvent on the dusted part before the lower-layer coated film is baked, and then forming an upper-layer coated film in different colors. CONSTITUTION:When a lower-layer coated film is formed by coating a paint in the first color on the undercoated film on a material to be painted, a solvent is coated on the dusted part around the lower-layer coated film, and then the lower-layer coated film is baked. A paint in the second color is subsequently coated, and baked to form an upper-layer coated film. Accordingly, the dust is dissolved partially and flattened, and the ruggedness of the dusted part is reduced to the utmost to improve the finished appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a multicolor coating method. More specifically, the present invention relates to a method for improving the appearance and finish quality of the upper layer coating at a portion corresponding to the dust portion of the lower layer coating.

[Prior Art] When painting automobile bodies, multicolor painting such as two-tone painting is performed.

Such multi-colored painting is, for example, as shown in FIG.
The first color paint is applied on the base coat 11 (2) provided on the object to be painted (1) and baked to form a lower coat film (3), and then on the base coat film (2). This is done by applying a second color paint so as to partially overlap the lower layer coating (3) and baking it to form the upper layer coating (4).

In this case, when the first color paint is applied on the base paint film (2), the dust (5) of the first color paint spreads and adheres to the periphery of the uniform bottom paint film (3).

When this is baked as it is to form the upper layer coating film (4), the appearance finish quality of the upper layer coating film (4a) on the dust part (6),
For example, skin and image clarity will deteriorate. This is because the unevenness of the dust part (6) affects the surface condition of the upper coating II (41), and the dust of the first color paint (5)
Due to the difference in properties (e.g. solvent resistance, coefficient of thermal expansion, etc.) between the dust (5) and the base coat III (21), dust (5) and the upper layer of the base coat III (21) This is because there is a difference in the surface condition of the coating 1ll (4).

[Object of the Invention] An object of the present invention is to eliminate the drawbacks of the prior art described above and to improve the quality of the external finish of the upper coating film in the dust area.

[Structure of the Invention] The present invention provides a multi-color coating system in which an upper layer coating film of a different color from the lower layer coating film is formed on top of the lower coating film, in which a solvent is applied to the dust part before baking the lower layer coating film. The present invention relates to a multicolor painting method characterized by:

[Embodiment] In the method of the present invention, when the first color paint is applied on the base coat on the object to be coated to form the lower coat, a solvent is applied to the dust area around the lower coat. Then, after baking the lower coating film, a second color paint is applied and baking to form the upper coating film.

By applying a solvent to the dust part before baking the lower coating film, the dust is partially dissolved and flattened, and as a result, the unevenness of the dust part is made as small as possible. Furthermore, the dissolved dust paint (first color paint) penetrates into the entire base paint film of the dust part, resulting in a uniform surface condition of the base paint film of the dust part, and the surface of the upper layer paint film. It will no longer have any negative effects. As a result of the above-mentioned effects, it is possible to obtain a multi-colored paint film in which the appearance finish quality of the upper layer paint film in the portion corresponding to the dust portion is the same as that in other portions.

The solvent applied to the dust portion is not particularly limited as long as it can dissolve the dust of the first color paint. Usually, the thinner of the first color paint is preferably used.

It is preferable to apply the solvent when the lower layer coating is in a substantially completely wet coating state. As the application method, an appropriate method such as a spray method or a brush coating method is adopted.

In the present invention, except for applying a solvent, the method of forming the lower layer coating, the masking method, the method of forming the upper layer coating, etc. may be the same as conventional methods.

In the above, the present invention was mainly explained using a two-tone coating as an example, but the present invention is not limited to such Example-3-, and the present invention is not limited to such example-3. It can be applied to three-color coatings that provide a film and multi-color coatings.

[Example 1] Next, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Example: Polybutadiene-based electrodeposition paint on a 0.8 AW thick dull steel plate treated with zinc phosphate chemical grain! Electric @ Painted, 170℃
This was baked for 25 minutes to form an electrodeposited coating film with a thickness of 20 mm, which was used as a test piece.

A black melamine-alkyd resin paint was applied to half of the test piece to a thickness of 25 mm after drying, and then paint thinner (30 parts by weight of alcohol-based solvent, 601 parts of ester-based solvent) was applied to the dust area. and 10 parts by weight of an aromatic hydrocarbon solvent) was applied, allowed to stand for 3 minutes, and then baked at 100° C. for 20 minutes to form a first color underlayer coating.

-4 Next, apply red melamine-alkyd resin paint to one half of the test piece so that it overlaps with a part of the lower coating film, and heat it to 140°C.
This was baked for 20 minutes to form an upper coating film of the second color with a thickness of 30 A1 m.

In the obtained upper layer coating, the skin and image clarity of the area corresponding to the dust area did not change at all compared to other areas.

Comparative Example In the example, two-tone painting was performed in the same manner as in the example except that no solvent was applied to the dust part.

In the resulting upper layer coating, the skin and image clarity of the area corresponding to the dust area were clearly inferior to other areas.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a coating film in conventional multicolor coating. (Main symbols in the drawings) (a: Base coat (3): Lower coat (4): Upper coat (5): Dust (6): Dust section Patent applicant Daihatsu Motor Co., Ltd. 7-

Claims (1)

[Claims] 1 A multicolor coating system in which an upper layer coating film of a different color from the lower layer coating film is formed on top of the lower coating film, characterized in that a solvent is applied to the dust part before baking the lower layer coating film. Painting method.