JPS61227869A - Electrostatic coating method for plastic automobile body part - Google Patents

Abstract

PURPOSE:To obtain a high-quality coated surface at low cost by electrostatically coating the boundary part between the main body of a metallic automobile body and the parts a plastic automobile body and electrostatically coating both automobile body and the pat in one step before the paint is dried. CONSTITUTION:When a plastic automobile body part is electrostatically coated while the part is attached to a metallic automobile body, an electrostatic paint is firstly coated on the boundary part between the metallic automobile body B and the plastic automobile body part S to form a continuous film F over the region extending from the surface of the metallic automobile body B to the surface of the plastic automobile body part S and then automobile body B and the plastic automobile body part S are electrostatically coated in one step before the continuous film F is dried. Since the electric resistance per unit volume of the continuous coated film F before dried is low, the surface of the automobile body part S is charged at the same potential as the surface of the metallic automobile body B through the continuous coated film and electrostatically coated under almost the same conditions as the metallic automobile body. Consequently, a high-quality coated surface is obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a resin car body in which resin car body parts can be electrostatically painted at the same time as the metal car body body while the resin car body parts are attached to the metal car body body. 'Relating to electrostatic coating methods for parts.

(Prior art) Automobile body bodies are manufactured using metal panel materials. In some cases, a resin sight shield S is attached thereto as a resin vehicle body part. When painting the body of a white motor vehicle, an undercoat is applied by electrodeposition, and then an intermediate and top coat is applied by electrostatic.

In electrostatic painting, the object to be coated, the automobile body, is used as an anode, and the paint spraying device is used as a cathode, and a high negative voltage is applied to it to create an electrostatic field between the two poles, and the sprayed paint particles are negatively charged.
This is a method of efficiently adsorbing paint to the object to be coated, which is the opposite polarity, and is widely used for painting automobile bodies, etc. due to its high coating efficiency. When painting a car body B having resin car body parts S as described above by electrostatic painting, the resin car body parts S are attached to the metal car body main body B, and these parts are electrostatically coated. When electrostatically painting at the same time in a paint booth, the resin car body part S receives more paint than the metal car body part B due to the difference in charge rate between the metal car body part B and the resin car body part S. The problem was that it was difficult to put on.

Therefore, in the past, the resin car body part S and the metal car body main body B were painted separately, and after each was painted, the resin car body part S was attached to the car body main body B, or they were painted at the same time. In some cases, the resin car body parts S are not undercoated by electrodeposition, but are coated with conductive brimer paint in advance on the resin car body parts S.

(Problems to be Solved by the Invention) However, as described above, painting the car body and resin car body parts separately not only increases painting costs, but also paints of the same color. Even if they are used, differences in hue inevitably occur, making it impossible to obtain high quality products. Also, even if the undercoating is done separately,
Not only was there a problem in that the color and texture of the paint applied to the car body and the paint applied to the resin parts did not match, but it also led to an increase in painting costs.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to electrostatically paint a metal car body body and a resin car body part at the same time to obtain a high-quality painted surface. purpose.

(Means for Solving the Problems) The present invention for achieving the above object provides that, after attaching a resin car body part to a metal car body, at least a boundary between the metal car body main body and the resin car body part A continuous coating film is formed from the surface of the metal car body part to the surface of the resin car body part by applying electrostatic paint to the part, and before the continuous coating film dries, the car body part and the resin part are coated with electrostatic paint. This is an electrostatic coating method for resin car body parts, characterized in that the resin car body parts are electrostatically painted in one body.

(Function) When electrostatic paint is applied to the boundary between the metal car body body and the resin car body parts to form a continuous coating film over these surfaces, the electrostatic paint film will disappear before it dries. However, since the electrical resistance per unit volume is very low, the surface of the resin car body parts is charged to the same potential as the surface of the metal car body through the continuous coating film, and the metal It becomes possible to perform electrostatic painting under almost the same conditions as for the car body itself.

(Example) Hereinafter, the electrostatic coating method for resin car body parts of the present invention will be described with reference to the drawings.

FIG. 3 is an enlarged cross-sectional view not showing the rear panel R and the sight shield S attached to the rear panel R that constitute the automobile body B shown in FIG. After finishing the glossy panel,
It is formed by welding various metal panels such as body side and floor main.

The metal car body body B thus formed is carried into the car body painting process shown in FIG. In this painting process, first, oil adhering to the car body B is completely removed in a degreasing process 1, and then an oxidation treatment is performed to form chemically stable inorganic eyes on the surface of the steel plate. This chemical conversion treatment activates the surface of the steel sheet and imparts antirust properties, thereby improving the adhesion of the coating film. The above degreasing process and chemical conversion treatment process 1
After the pretreatment consisting of is completed, an undercoat 2 is usually applied by electrodeposition, and the undercoat surface is baked and hardened 3 in a drying oven. Next, in a step indicated by reference numeral 4, the undercoat surface is wiped to remove unevenness in the coating, and dust and the like adhering to the vehicle body B are wiped off (dust removal wipe).

The resin vehicle body parts S are attached to the vehicle body B with the undercoating completed in this manner using screws D or the like.

After the installation of the resin car body parts S is completed, electrostatic painting is performed to form a coating surface for the intermediate coating.The paint used for this electrostatic coating is sprayed and In the continuous coating film forming step indicated by reference numeral 5 in the figure, the spray is mainly applied to the boundary between the vehicle body B and the resin vehicle body part S. As a result, a continuous coating film F is formed over the surface of the vehicle body B and the surface of the resin vehicle body component S. The paint for electrostatic coating that forms this continuous coating film F contains a solvent in a wet state before drying, so the electrical resistance per unit volume is about 10 to 10"Ωcm, which is extremely high. Therefore, before this continuous coating film F dries, if the object to be coated, the car body B, is placed in the electrostatic coating booth where the intermediate coating 6 is applied and electrostatic coating is performed, the electrical resistance will increase. The surfaces of the resin car body part S and the car body body B have almost the same potential through the continuous coating film F which is in a very low state.

Therefore, in the intermediate coating process 6, the surface of the vehicle body B made of a steel plate and the surface of the vehicle body part S made of resin are electrostatically coated under substantially the same conditions. After completing the intermediate coating in this way,
The object to be coated is placed in a drying oven and the intermediate coated film surface is dried and cured (7).

Next, in order to perform topcoat coating 0, as in the case of intermediate coating 6, before putting the object to be coated into the electrostatic coating booth for topcoating, spray the paint used for electrostatic coating. It is sprayed mainly on the boundary between the car body B and the resin car body part S to form a continuous coating film F over the surface of the car body B and the resin car body part S (Step 9). . Incidentally, before this step 9, blanking and masking 8 are performed on non-painted areas. Then, before this continuous coating film F dries, the object to be coated is put into an electrostatic coating booth for topcoating, and a topcoat coating is performed.

When applying this top coat, the surface of the car body B and the surface of the resin car body parts S are at almost the same potential as in the case of the intermediate coat, so each of them is kept static under the same conditions. Electrical coating is applied. As a result, when the top coating film is baked, the coating film formed on each surface becomes uniform in color, coating surface, etc., and a high-quality coating is achieved.

(Effects of the Invention) As described above, according to the present invention, after a resin car body part is attached to a metal car body main body, at least the boundary between the metal car body main body and the resin car body part is fixed. An electric paint is applied to form a continuous coating film from the surface of the metal car body body to the surface of the resin car body part, and before the continuous coating film dries, the car body body and the resin car body part are coated. Since the and are electrostatically coated in one piece, it is now possible to electrostatically coat resin car body parts at the same time as the car body, which not only greatly reduces painting costs, but also
Since electrostatic painting is performed at the same time, the color of the coating surface formed on the resin car body parts and the coating surface H are uniform with the car body itself, making it possible to form a high-quality coating surface. You can get results.

[Brief Description of the Drawings] Fig. 1 is a process diagram showing a painting process according to an embodiment of the electrostatic coating method of the present invention, and Fig. 2 is a perspective view showing an example of resin car body parts attached to a car body body. , FIG. 3 is an enlarged sectional view showing a state in which the resin car body parts are attached to the car body main body. B...Metal car body body, S...Resin car body parts, 5
．． 9...Continuous coating film formation process, 6...Intermediate coating process, 10...Top coating process. Patent applicant Nissan Motor Co., Ltd. = 9- ・)? Peng's late Qfuji

Claims (1)

[Claims] After attaching the resin car body parts to the metal car body, an electrostatic paint is applied to the boundary between the metal car body and the resin car body parts to remove the resin car body parts from the surface of the metal car body. A resin-made vehicle, characterized in that a continuous coating film is formed over the surface of the vehicle body, and before the continuous coating film dries, the vehicle body body and the resin vehicle body parts are electrostatically coated as one body. Electrostatic painting method for car body parts.