JPH0263579A - Method of repairing pearl painting - Google Patents

Abstract

PURPOSE:To easily repair the color base of pearl painting by removing foreign matter form the surface of a color base coated film, then applying a color base paint again on this surface and forcibly evaporating the solvent contained in this paint. CONSTITUTION:After the foreign matter is chipped away from the surface of the color base coated film, the color base paint is applied on this surface and the solvent contained in the paint is forcibly evaporated. A mica base paint and clear paint are applied by wet on wet application on the surface in this state. The surface of the color base coated film is dried in this way and the pearl coated film is formed without mingling of this coated film and the mica base coated film with each other. The repair in a production line is, therefore, possible without degrading brightness of reflectivity and the productivity of the pearl painting is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for repairing pearl coating applied to, for example, automobile bodies, and facilitates repair of coating defects.

(Prior Art) In recent years, in the painting of automobile bodies, there has been a demand for improved anti-corrosion performance as well as diversification of paint colors, and this has become one of the important factors responsible for the development of the automobile industry. For example, multicolor coating (so-called two-tone coating), pearl coating according to the present invention, etc. are examples thereof.

The conventionally known pearl coating has a coating film structure as shown in FIG. That is, after applying the electrodeposition coating 0, which is an undercoat, to the steel plate 9 constituting the outer panel of the automobile, the intermediate coating 1 is applied. Electrodeposition coating equipment 0 is a coating applied for the purpose of improving the rust prevention ability of the steel plate 9, and usually includes a degreasing process to remove oil and dust attached to the surface of the steel plate, and a degreasing process to improve the adhesion between the electrodeposition paint and the steel plate. After applying a chemical conversion treatment process to form an oxide film on the surface of the steel plate in order to maintain the surface of the steel plate, the car body is painted using a so-called dipping coating method in which the car body is completely immersed, and then dried. On the other hand, the intermediate coating device 1 is the electrodeposition coating device 0.
Similarly, it is applied for the purpose of improving the rust prevention ability of the steel plate 9, maintaining adhesion with the top coat, and improving the smoothness of the top coat, and is usually applied with an electrostatic coating gun, Particularly in recent years, in order to improve coating efficiency, paint is mainly applied to the exterior of the vehicle body using a rotary atomizing electrostatic paint gun and then dried.

In this manner, with the undercoat 0 and intermediate coat 1 applied, sanding is performed to remove foreign matter from the surface of the intermediate coat and to smooth the surface. This sanding is generally known as water sanding, which is a method that uses water, and dry sanding, which is a method that does not use water. are selected accordingly.

As shown in FIG. 9, the color base paint 12 is applied to the workpiece on which the intermediate coating film has been formed in the first 1-coating process (color base coating process 1) and dried (color base drying process 2). . Then, in a second two-coating process, mica base paint 13 (mica base coating process 6) and clear paint 14 (clear coating process 7) are applied onto this color base coating film without a drying process (hereinafter referred to as wet coating). After applying (referred to as on-wet painting), both paints 13,1
By drying 4 at the same time (mica base and clear drying step 8), the pearl coating is completed.

The color base paint 12 is a paint made of pigment and resin, and is a paint film that exhibits the color felt when pearl coating is visually observed. Furthermore, the mica-based paint 13 is a paint that does not contain any pigment and is made of mica flakes and resin, and constitutes a coating film in which the light incident on the pearl coating film is diffusely reflected by the mica flakes. These mica pieces cause a unique diffused reflection that is different from the aluminum pieces contained in conventional so-called metallic paints, thereby giving the automobile body a beautiful appearance. Further, the clear paint 14 is a paint made only of resin, which prevents deterioration of the paint film due to ultraviolet rays and the like, and provides a pearlescent luster. These color base paints 1 and 2, mica base paint 13, and clear paint 14 are usually applied with an electrostatic paint gun, and, like the intermediate paint, in recent years, in order to improve the coating efficiency, rotary atomization has been applied. A coating method using a chemical metering gun is often used.

(Problem to be Solved by the Invention) However, in the conventional pearl coating described above, when a coating defect such as adhesion of foreign matter is found on the color base coating film 12, the foreign matter at the defective site is removed. Afterwards, it was necessary to apply the color base paint again and dry it using heating means such as a simple light bulb, which is what is called spot repair. This spot repair requires a drying process of 20 minutes at approximately 140°C, similar to the normal drying process.
It was not possible to do this on the production line, so the vehicle body was held outside the production line. In addition, under process conditions where it is not possible to secure an off-line space for holding the car body, as shown in FIG.
After the foreign matter on the surface was removed (defective area polishing step 3), it was again put into the regular topcoating step, and repainting was performed from the first topcoat step.

The reason for drying the color base paint 12, which is a correction paint, is that after applying the color base paint,
If the mica base paint 13 is applied by wet-on-wet painting without drying the paint, the boundary between the color base paint layer and the mica base paint layer will mix with each other, resulting in a decrease in image clarity after pearl coating is completed. This is because such a problem occurs.

Therefore, the conventional pearl coating method has the disadvantage that productivity is significantly reduced when coating defects occur in the color base coating film. In addition, so-called double spot repairs require highly skilled skills in order to match the colors and ensure that the quality of the painted appearance at the border exceeds a predetermined value, and there is a problem in that the degree of freedom for the operator is small. .

The present invention has been made in view of the drawbacks and problems associated with the above-mentioned conventional techniques, and an object of the present invention is to easily repair the color base of pearl coating without impeding productivity.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a step of polishing a defective area of removing foreign matter on the surface of the color base coating film after applying a color base paint to the surface of the workpiece and drying it; The method includes a color base re-applying step of reapplying the color base paint to the area from which the foreign matter has been removed, and a forced solvent evaporation step of forcibly evaporating the solvent contained in the color base paint. This is a method for repairing pearl coating by applying a mica-based paint containing particles and a clear paint, and then drying the mica-based paint and the clear paint at the same time.

(Function) In the present invention configured as described above, the color base paint is applied after foreign matter on the surface of the color base paint film is scraped and removed, the solvent contained in the paint is forcibly evaporated, and the mica is applied in this state. Since the base paint and the clear paint are applied by wet-on-wet painting, the surface of the color base paint film dries, and the paint film and the mica base paint film form a pearly paint film without mixing with each other.

Therefore, repairs can be made within the production line without deteriorating image clarity, and the productivity of pearl coating is improved.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a process diagram of the top coating process showing a pearl coating repair method according to an embodiment of the present invention, and FIGS.
FIG. 4 is a perspective view showing the color base re-applying step shown in FIG. 1, and FIG.
FIG. 6 is a perspective view showing the forced evaporation process of the solvent, and FIG. 6 is a partially sectional perspective view showing the structure of the coating film after the pearl coating shown in FIG. 1 is completed.

The pearl coating in this example is applied to the exterior coating of a car body such as a boat, and the above-mentioned undercoat and intermediate coating are applied, and then the sanding is applied to the intermediate coating, and then the top coating described later is applied. It is expected that this will be carried out. However, it goes without saying that the present invention is not limited to painting the outer panels of a vehicle body as shown in this embodiment, and can be applied to parts painting, bumper painting, and the like.

As shown in FIG. 1, the top coating process of this embodiment includes regular processes such as color base coating process 1, color base drying process 2, mica base coating process 6, clear coating process 7, mica base and clear drying process 8, and defective The color base repair process includes a partial polishing process 3, a color base recoating process 4, and a forced solvent evaporation process 5.

Color base coating step 1 is carried out in a coating booth maintained at a predetermined wind speed, temperature and humidity, and the vehicle body transported by a coating conveyor is passed through a plurality of automatically rotating atomizing electrostatic coating guns ( Most of the outer panels of the vehicle body are painted using a so-called bell paint gun, and the remaining parts are sprayed, for example, by a painting robot using pre-taught movements.

This color base paint 12 is typically applied to a film thickness of 20 μm. Here, when painting the color base, a method to prevent surface flow defects (so-called sagging) of the paint while ensuring the film thickness is to arrange the electrostatic painting gun in multiple stages and gradually increase the film thickness at each stage. There is a way to increase this. According to such a coating method, the solvent contained in the color base paint naturally evaporates to some extent between each stage, thereby making it possible to prevent surface flow.

After completing the color base coating step 1, the vehicle body is guided into a drying device at a predetermined interval. This drying device is a hot air drying device using butane gas or the like as fuel, and the drying zone is usually divided into a dawn zone on the inlet side and a convection zone on the outlet side.

The daylight zone is a zone where a shielding plate is provided between the hot air heated by butane gas and the car body, and the car body is heated by radiant heat from the shielding plate, and the hot air is not blown directly onto the car body. It is possible to prevent dust from adhering to the painted surface before drying. The surface of the coating film on the car body that has passed through this daylight zone is cured to some extent, and further crosslinked and cured in the convection zone where hot air circulates within the drying device. This convection zone has better drying efficiency than the dawn zone, and is a suitable drying zone for painted surfaces where there is no risk of dust or the like adhering.

After completing the color base coating process 1 and color base drying process 2 as described above, the vehicle body is transported to an inspection process (not shown) by a coating conveyor.

In the inspection step, the dried color base coating film 12 is inspected for coating defects, and areas that fail are checked.

In this embodiment, the repair process is provided on the conveyor between this inspection process and the mica base coating process 6, which will be described later. In this repair process, first remove the foreign matter 15, which is the paint defect, using a knife 16 (see Figure 2).
The surface of this repaired area is polished with sandpaper 17 (see FIG. 3) to make it flat (defect area polishing step 3). The defective portion polishing step 3 is a step of repairing only the defective portions checked in the inspection step. The sandpaper 17 is
It is preferable to use a fine material of 4400 or more.

A color base paint 12a is applied to the smoothed area after polishing the defective area (see FIG. 4). Normally, when the color base paint 12a forms the paint film 12 after drying, the pigment and resin constituting the paint film are approximately 70 to 8
0%, and the remainder is a solvent. This solvent is mixed to improve the dispersibility of the pigment in the resin component and to reduce the viscosity of the paint to a certain extent and improve painting workability. A solvent is used. Therefore, if left at room temperature for a long time, most of the solvent will evaporate, but this will cause new dust to adhere to the painted surface and cause paint defects again. After this color base re-applying step 4, a step is provided to evaporate the solvent for strong purpose.

Specifically, as shown in FIG. 5, evaporation of the solvent is promoted by blowing dehumidified and dust-removed air 19 onto the repaired area.

The pressure of this air 19 is 2 to 3 kg/cJ.
Moderately suitable. All of these repair processes are carried out on the coating conveyor, that is, within the production line, and can be carried out in a short period of time without requiring a particularly large space. Furthermore, since this repair work does not completely cure the color base paint 12a but evaporates the solvent, it can be easily carried out by any skilled person who can perform color base coating work. .

FIG. 7 is a perspective view showing another embodiment of the present invention. In this embodiment, heated air 20 is blown instead of the air 19 of the first embodiment, and the evaporation rate of the solvent is further increased. It was designed to improve the performance. As this air heating means, it is sufficient to use, for example, a household hair dryer 21 or the like.

Vehicle bodies with paint defects on the color base coating film 12 undergo the above repair process, and vehicle bodies with no defects are forwarded from the color base drying process 2 to the second top coating process, which is mica base coating. It is carried into a coating process 6 and a clear coating process 7. Both coating steps 6 and 7 are
The painting booth in which the color base coating step 1 was performed may be used again, or a different painting booth may be used, and the method of handling the vehicle body may be suitably selected depending on the production volume and the like. In other words, if the space of the painting factory is small and you want to reduce equipment costs, one painting booth and drying device can be used for the first topcoating process of the color base coating process 1 and the mica base coating process for the second topcoating process. It may also be used in the clear coating steps 6 and 7.

The mica base coating step 6 and clear coating step 7 are as follows:
This is done by so-called wet-on-wet painting, in which mica-based paint is applied by an automatic electrostatic painting gun in the first stage installed in the painting booth, and then clear is applied at predetermined intervals by an automatic electrostatic painting gun in the second stage. Paint is applied. The automatic electrostatic painting guns installed in these 1st and 2nd stages are devices for coating most of the outer skin of the car body, and parts that are not painted by the automatic electrostatic painting guns can be repainted by a painting robot, for example. It is meant to be done. In this respect, it is similar to the color-based painting described above. Therefore, if an automatic color change device is added to the automatic electrostatic painting gun to change the paint for each vehicle body, it will be possible to apply one coat as described above. Processing using a booth becomes possible.

The mica base coating film 13 and clear coating film 14 coated by wet-on-wet coating in this manner are dried by a drying device similar to the color base drying device. The vehicle body that has been completely coated with the final top coat is transported to a final inspection process (not shown), where the final paint defects are inspected.

Next, the operation of this embodiment will be explained.

After finishing the color base coating step 1 of the regular process, a vehicle body in which a paint defect is found in the inspection step is transported to a repair step, and after removing foreign matter 15 on the surface of the color base coating film 12 by scraping it off, a color base paint 12a is applied. Air 19 is sprayed onto this applied area to forcibly evaporate the solvent contained in the paint 12a, and in this state, the mica base paint 13 and clear paint 14 are applied by wet-on-wet painting, so that the surface of the color base paint film 12 is After drying, the coating film 12
A pearl coating film is formed without mixing the mica base coating film 13 and the mica base coating film 13 with each other.

Therefore, repairs can be made within the production line without deteriorating image clarity, and the productivity of pearl coating is improved.

In addition, this repair work can be carried out by any worker who is skilled in color-based spraying.
This has the effect of increasing the degree of freedom for the worker.

(Effects of the Invention) As described above, according to the present invention, defects in a color base paint film can be repaired by the steps of removing foreign matter on the surface of the color base paint film and reapplying the color base paint to the defective area. The method consists of a step of forcibly evaporating the solvent contained in the color base paint, and the mica base paint and clear paint are applied over the color base paint, so that the color base paint film and the mica base paint film do not overlap with each other. A pearl coating film is formed without mixing with each other. Therefore, repairs can be made within the production line without deteriorating image clarity, and the productivity of pearl coating is improved, which has a great practical effect.

[Brief explanation of the drawing]

Fig. 1 is a process diagram of a seven-coat painting process showing a pearl coating repair method according to an embodiment of the present invention, Figs. FIG. 8 is a cross-sectional view showing a coating film constituting the outer panel of a vehicle body, and FIG. 9 is a process diagram showing a conventional pearl coating repair method. Fig. 1 1... Color base coating process, 2... Color base drying process, 3... Defect area polishing process, 4... Color base re-coating process, 5... Solvent forced evaporation process, 6... Mica base coating process, 7... Clear coating process, 8... Mica base, clear drying process, 9...
Steel plate (work), 15...Painting defect (foreign object). Figure 8

Claims (1)

[Claims] After applying the color base paint to the work surface and drying it, a defect site polishing step of removing foreign matter on the surface of the color base paint film, and a color base reapplying step of reapplying the color base paint to the site from which the foreign matter was removed; and a forced solvent evaporation step of forcibly evaporating the solvent contained in the color base paint, and after applying the mica base paint containing mica flakes on the color base paint film and applying the clear paint, A method of repairing pearl paint by drying mica-based paint and clear paint at the same time.