JPS59363A - Method for painting resin parts of vehicle - Google Patents

Abstract

PURPOSE:To carry out the titled painting in good productivity and in a satisfiable design in a line separate from the painting line of a vehicle body, in a super-solid painting method of vehicle resin parts, by successively painting an under coat painting surface with solid paints having high and low covering forces and baking the same. CONSTITUTION:For example, one component type liquid urethane paint is at first blown to an urethane resin bamper in a painting line separated from that of a vehicle body general part and baked to complete under coat painting. In the next step, the surface of said parts is polished according to necessity and preparatory work such as masking is carried out. Subsequently, a solid paint is blown over the all surface of the aforementioned under coat painting surface to sufficiently cover the under coat painting surface. The paint used in this painting hase same color or a same color type with the vehicle body general part but is extremely high in covering force, poor in transparent feeling and comprises a so called solid paint containing not metal powder or mica and, as the paint resin, acryl-modified urethane resin is used from the point of view of weatherability. After painting, solid paint low in covering force and high in transparency is applied to the surface thereof and both coating surfaces are simultaneously baked and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION The disclosed technology belongs to the technical field of painting resin bumpers and the like of automobiles with a transparent appearance.

Therefore, this invention relates to a super solid coating method for coating resin parts such as automobile resin pumps, in which an undercoat is applied and then a transparent topcoat with low hiding power is applied. After applying the undercoat, dry sanding, water sanding, etc. are performed as necessary, and then a solid paint with a large adhesion force and no transparency is applied to a predetermined thickness, and then a layer of hiding power is applied to the surface of the solid paint. This invention relates to a method for painting resin parts for vehicles, in which a small transparent solid paint is applied to a predetermined film thickness, and finally both coated surfaces are baked simultaneously so that the super solid coated surface is 1q.

As is well known, vehicles such as automobiles have many metal parts for protection of mechanical parts and safety for passengers, and there are especially many metal parts in external shrines. Painting is applied to improve appearance, but in recent years, aesthetics have become even more desirable, and so-called super solid paints, solid paints and aflare paints, which have a sense of transparency, have been developed. It's starting to get hired.

On the other hand, resin parts are being replaced and installed in large numbers due to conditions such as saving resources, saving energy, and reducing costs to 1. For example, there is also a need for safety in automobiles, such as a bumper that can be moved. The conventional metal plated bumpers have been replaced by urethane elastomer bumpers.

Therefore, it has become desirable to paint general metal car body parts and resin parts in the same color from the viewpoint of appearance, but if the base is metal or resin, there are differences in painting techniques, for example, in terms of the presence or absence of antiseptic function. As a result, there are various problems,
In particular, there were many obstacles to the above-mentioned super solid coating that could not be put into practical use easily.

In other words, since vehicle painting technology originally developed to suit metal panels, etc., it is usually 3 coats 1 to 1 coat. While it can be done using a 3-layer formation method called the 3-beak method, which includes an undercoat and an intermediate coat,
Resin parts do not require anti-corrosion treatment and have poor heat resistance, while metal parts have poor compatibility, potentially making it impossible to paint them at the same time when they are integrally attached to the vehicle body.

Therefore, resin parts are generally separated from the car body and painted on a separate line, and due to mismatched materials, they are not painted at the same time, making it difficult to paint the car body and resin parts in the same color.

In particular, urethane paints and super solid paints for polypropylene bumpers, which have been widely used in recent years, have been a bottleneck in painting the same color.

As mentioned above, since intermediate coating is not required for resin parts, the general body of the car will have a transparent appearance with intermediate coating and top coating.
While other techniques are used, it is necessary to achieve this with only the top coat, which is basically extremely difficult, and even if it were possible, the top coat would have to be thin in order to exhibit the same transparency as the general car body. In some cases, there is a risk that a defect known to those skilled in the art, so-called sagging, where the undercoat paint color can be seen through the topcoat may occur, and if the paint film is made thicker to counter this, sagging and pinholes will form, resulting in poor coating. There was a problem.

Therefore, in reality, resin parts are painted with solid paint without transparency, and when the car body is painted with super solid paint, there is an unsatisfactory lack of color consistency, which reduces the design quality and reduces commercial value. connected to benefits. Ta.

On the other hand, even if super solid painting is applied to resin parts using the 3-coat, 3-bake method, there are disadvantages in that the number of man-hours is large, the work is complicated, and the cost is high.

The purpose of this invention is to solve the technical problem of super solid coating for vehicle resin parts based on the above-mentioned prior art, and to achieve high productivity and good design while performing the coating separately from the general vehicle body. An excellent coating for vehicle resin parts that is completely satisfactory, can be cost-effective, and can match the color tone of the vehicle body, and is beneficial to the field of resin parts that is the most popular in the vehicle industry. The purpose is to provide a method.

The structure of the present invention in accordance with the above-mentioned purpose is to apply super solid painting to the car body, but to apply resin parts on a separate painting line from the car body-crotch area, and then apply a predetermined undercoat to the resin parts. After that, air polishing and water polishing are performed as necessary to bring out good adhesion to the surface, and when good adhesion is obtained, pigment it! A solid paint with a relatively high margin and low transparency is sprayed with a concealing film thickness of 25μ or less compared to the undercoat, and the film thickness after drying is 15 to 25μ, and then the same color as the solid paint is applied. , use a highly transparent solid paint with a relatively low pigment concentration of at least the same color as above, and bake with a film thickness of 1 after drying.
The gist of this is that a technical measure was taken in which the spray paint was applied so that the thickness was 5 to 40 microns, and then both were baked and dried at the same time to form a transparent super solid coating.

Next, a detailed explanation of the present invention will be as follows.

The target resin part is a urethane resin bumper for an automobile, and the bumper, which has been injection molded in a predetermined manner, is painted in the next super solid painting process on a separate painting line from the car body-crotch area.

First, in the first step, a one-component urethane paint is used and the film thickness after drying is 15~
Spray to about 45μ, then 10 to 120°
Baking is performed in step C to complete the undercoating.

Next, if there are defects such as contamination formed on the paint film for the resin part that has been painted with the undercoat, #
300~#1200Pi! Dry sand the surface using sandpaper with a fine grain size to ensure adhesion of the top coat.

In this case, it goes without saying that this work to guarantee the quality is not necessary if the quality is guaranteed through inspection or the like.

Then, the painted surface is cleaned and preparatory work such as masking for the next step is performed as appropriate.

Next, the following solid paint is sprayed on the surface of the above undercoat paint using an air spray gun or an electrostatic air spray gun.
μ, that is, the undercoat surface is sufficiently or substantially hidden.

Therefore, although the paint used for the solid painting is the same color or the same color as the car body and crotch, it has a much stronger hiding power, is less transparent, and does not contain metal powder or mica. The pigment is organic or inorganic (mainly inorganic for solids), and the paint resin is an acrylic-modified urethane resin in consideration of weather resistance.

In this case, the acrylic modified urethane resin may be the same as the resin of the solid paint for the uppermost layer coating, but if they are likely to be compatible when coated over and over again, it is desirable to select incompatible resins.

In addition, as the thinner used for the paint, low boiling point Al T1 is used so that the wet part of the paint dries as quickly as possible after spraying.
-Use methanol as a refill, and to further prevent compatibility,
It is desirable to add an appropriate surface tension modifier.

Next, 1 to 10 minutes after the above solid coating, the top surface of the coating (A) is sprayed with an air spray gun or an electrostatic air spray gun, so that the pigment concentration is relatively low, the transparency is large, and the hiding film thickness is 60μ or more. Baked dry film thickness 15 to 40
Blow 1 so that it becomes μ.

In this case, the solid paint has the same color as the underlying solid paint, and the pigment is organic or the inorganic resin is urethane.

Then, care should be taken to select an abrasive quality that avoids I-J compatibility with the lower part.

In addition, Shinno uses a high-boiling point solvent, such as h-rubitol acetate, in order to obtain a good texture.

Furthermore, the compatibility and weather resistance of the additives for the surface conditioner should be taken into consideration as described above.

After the above-mentioned overcoat and 7-minute off-time, the 2-component type paint was heated to 10-120°C.
Bake dry for 10 to 45 minutes to obtain a transparent super solid coating.

It goes without saying that the embodiments of the present invention are not limited to the above-mentioned embodiments; for example, extensions and ornaments can be applied in addition to resin part numbers and bumpers, and the paint may be epoxy amine-based or dispersed. In addition, a two-component type with a baking temperature controlled from room temperature to 120°0 is good, and in addition, water-resistant water sanding paper is used for the undercoating process, and inorganic pigments are used for solid paints. It is possible to use toluene, xylene, acid-resistant ethyl as the thinner, and use a rotary electrostatic atomizer for spraying.

Next, an experimental example based on the above embodiment will be shown.

Resin parts Black urethane resin bumper undercoat for passenger cars Undercoat after cleaning treatment Flexene #60
After baking 0 Gray E, spray with an air spray gun DeVilbiss JGA 502#777 with a film thickness of 30μ, drying process, baking at 100°C for 20 minutes, dry air sanding, lightly air sanding with a #600 dry sanding machine, and wipe the back end with gas wiping solid. Layering M (1) Spray the next slow red type A paint with an air spray gun DeVilbis JG A 502#777 with a baking dry film thickness of 15 to 20 μm.

(2) 5 minutes after applying the above Film after baking and drying continuous light system B paint Air spray with a thickness of 25-35μ Gun Devil Bilbis JGA502# Spray 1 at 777.

Baking drying Flashco A time 7 minutes 120'0
Bake for 40 minutes () and dry.

Car body assembly When installed on a car body painted super solid (red) on a separate painting line, the bumper was also sufficiently transparent, and the car body color transparency and aesthetic layered paint (11th place was PWC) Regarding the above experimental example For comparison! Therefore, the following comparative experiment was conducted.

<Comparative experiment example 1> Resin parts Same bumper undercoat as the experiment example Same paint as the experiment example Dry sanding Same dry sanding solid paint as the experiment example including white gas wiping Next, bake continuous light system coating C and dry film thickness 35 ~ 4
0μ design, spraying with air spray gun #777, baking drying, 120°C14 after flash time.
0 minute burn-in car body assembly When the bumper was assembled onto a car body painted super solid (red) on a separate paint line, the bumper lacked transparency and did not match aesthetically with the car body, creating a sense of discomfort.

(Units are PWC) Comparative Experiment Example 2> Regarding resin parts, undercoating and dry sanding - Same as Comparative Experiment Example 1, and the pigment used in the previous example was used for paint, and the thinner was used for paint B. A solid paint with a dry film thickness of 30 to 35 μm was sprayed with spray gun #777, baked at 120°C for 40 minutes, and after drying, a part of the painted surface was air-polished again using the above-mentioned method. After dry sanding and wiping with white gas using the same method as above, it was baked and dried using the coating B of the experimental example described above, and after drying, it was sprayed 4 times with a spray gun #777 at a 35μ setting 61. It was baked at 120'C for 140 minutes and dried.

When the completed Bamba that had been dried in this way was assembled on a car body painted super solid (red) on a separate painting line, it had a transparent appearance and did not feel strange.

However, compared to the above-mentioned experimental example of this invention, there is more painting in one step, so the number of man-hours is about 1.7 times greater, and the amount of paint used is about twice as much, which increases time and cost accordingly. It became clear that

According to other experimental examples, when spraying only a transparent paint with poor hiding properties, a coating thickness of 50 μm or less causes flaking, while a coating thickness of 45 to 50 μm or more causes sagging or sagging. It has been found that pinhole defects occur.

As described above, according to the present invention, the excellent effect that super solid painting of resin parts of a vehicle can basically be performed reliably on a separate line from the car body painting is achieved.

Also, unlike the car body, super solid painting is not done using the 3-piece 1-3 bake painting method, which requires less man-hours and less paint, which means less work, less work, and less management. , 'It also has the excellent effect of improving work efficiency and reducing costs.

In addition, there is no sagging or pinhole formation on the painted surface, so there is no reduction in commercial value or product defects.

Thus, by spraying a non-transparent solid paint with great concealing ability onto the undercoat surface of the resin component, the effect of reliably concealing the undercoat surface can be achieved.

Furthermore, by spraying a highly transparent solid paint with low hiding ability onto the painted surface with high hiding ability, a transparent painted surface can be obtained.

In addition, by baking and drying after both coatings, both functions are fixed at the same time, producing an excellent effect of creating a super solid painted surface.

Claims (1)

[Claims] In the super solid painting and J painting methods, a transparent top coat is applied after the undercoat is applied to vehicle resin parts, and then baked on. A vehicle resin characterized in that a paint is applied, then a solid paint with low hiding power is applied to the solid painted surface, and both coated surfaces are simultaneously baked and dried to obtain a super solid paint. How to paint parts.