JP2537523B2 - Two-ton coating method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a two-tone painting method for painting the lower part of a vehicle body of an automobile in a color different from the color of the entire vehicle body.

[Prior Art] Conventionally, in a method of coating a vehicle body of an automobile, so-called two-tone coating, in which a lower portion of the vehicle body is coated with a color different from the color of the entire vehicle body, is generally well known.

In the case of applying this two-tone coating, conventionally, the entire vehicle body is first subjected to the ordinary coating in which the intermediate coating and the top coating are sequentially applied after the electrodeposition coating as the undercoat is performed, and after the normal coating step is finished, Two-tone coating is applied only to the lower part of the vehicle body by using a paint of a predetermined color different from the top coating color which is the overall color of the vehicle body. Therefore, in this case, as shown in FIG. 4, the coating film of the two-tone coating portion includes the electrodeposition coating film 33 that directly covers the steel plate 32 that forms the vehicle body, the intermediate coating film 35, and the entire body color. Top coat 36
And a two-tone paint film 38
The thicknesses of 33, 35, 36 and 38 are combined to obtain a predetermined film thickness.

Then, when performing the two-tone painting, the two-tone painting is performed by overspraying the portion 3 other than the lower portion 31a of the vehicle body.
Prior to two-tone painting, masking 37 is applied to the entire color portion 31b other than the lower part 31a of the vehicle body prior to two-tone painting, in order to prevent adhesion to the top coating film of 1b (overall color portion). I am trying.

[Problems to be Solved by the Invention] However, the whole color part 31b of the vehicle body is a two-tone painted part 3
Since the area is considerably larger than 1a and the shape is complicated, the masking 37 becomes very large-scaled, and it takes time to construct and remove the masking 37, which causes a problem of high cost.

To solve this problem, after electrodeposition coating is applied to the entire vehicle body, a two-tone paint is applied to the lower part of the vehicle body during intermediate coating using a two-tone paint, and a masking is applied to the lower part of the vehicle body, and then a paint of the entire body color It is conceivable that the vehicle body may be divided into the entire color portion and the two-tone coating portion by performing a relatively simple masking that partially covers only the lower portion of the vehicle body by applying the top coating with.

However, in this case, since the coating film of the two-tone coating portion is composed of only two coating films of the electrodeposition coating film and the two-tone coating film (intermediate coating film), the predetermined thickness is set. Therefore, the so-called chipping resistance, which prevents the base steel plate from being scratched by collision of foreign matter, is reduced, and the coating film on the lower part of the vehicle body may be damaged by stone spattering while the vehicle is running. There is a problem that the base steel sheet is liable to rust at an early stage relatively easily because of scratching and tearing.

[Object of the Invention] The present invention has been made in order to solve the above-mentioned problems and uses a two-tone urethane coating capable of obtaining a thicker coating film thickness on the lower part of a vehicle body than a conventional coating composition. By applying coating, a two-tone coating method that can secure the coating thickness of this two-tone coating part and maintain chipping resistance, and also simplify masking at the time of coating and reduce coating cost. The purpose is to provide.

[Means for Solving the Problems] Therefore, the present invention provides a two-tone coating method for painting the lower part of the body of an automobile in a color different from the color of the entire body, after applying electrodeposition coating to the entire body. Urethane coating is applied only to the lower part of the vehicle body, then intermediate coating is applied to at least parts other than the lower part of the vehicle body, and then overcoating is applied to parts other than the lower part of the vehicle body. Is.

[Effect of the Invention] According to the present invention, in the two-tone coating method of coating the lower part of the vehicle body with a color different from the color of the entire vehicle body, only the lower part of the vehicle body is subjected to electrodeposition coating after applying the electrodeposition coating to the entire vehicle body. Since urethane coating with a relatively large coating thickness is applied, the thickness of the electrodeposition coating and this urethane coating are combined to obtain a predetermined coating thickness sufficient to secure sufficient chipping resistance. be able to.

In addition, the urethane coating is performed using a urethane coating of a predetermined color different from the overall color of the vehicle body, masking is applied to the lower portion of the vehicle body after the urethane coating, and then at least a portion other than the lower portion of the vehicle body is intermediately coated. Since the overcoating is applied by using the paint of the entire color after applying the above, the masking can be relatively simple to partially cover only the lower part of the vehicle body. As a result, it is possible to greatly simplify the masking work and removal work and reduce the coating cost, as compared with the conventional technique in which large-scale masking is applied to parts other than the lower part of the vehicle body.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the vehicle body 1 of the automobile to which the coating method according to the embodiment of the present invention is applied is subjected to two-tone painting in which the lower portion 1a of the vehicle body is painted in a color different from the color of the entire vehicle body. There is.

The car body 1 is painted by the following painting process,
As a result, it has a coating film structure as shown in FIG.

(1) First Step: Electrodeposition Coating First, the vehicle body 1 is immersed in an electrodeposition tank to be subjected to electrodeposition coating as an undercoat over the entire surface of the vehicle body 1, and a steel plate 2 forming the vehicle body 1 is coated with an electrodeposition coating 3 Apply directly.

(2) Second step: urethane coating After the electrodeposition coating 3 is dried, a urethane paint of a predetermined color different from the overall color of the vehicle body 1 is used to lower the vehicle body 1a.
Apply urethane coating on only the. That is, the lower part of the vehicle body
A urethane coating film 4 is formed on the electrodeposition coating film 3 of 1a.

At this time, the urethane coating is applied even slightly above the two-tone color portion 1a to be separately painted in two-tone color in order to reliably prevent the unpainted portion from being left unpainted at the coating boundary portion. Further, the urethane paint can obtain a thicker coating film thickness than that of a normal paint, and the thickness of the electrodeposition coating film 3 and the urethane coating film 4 are combined to ensure sufficient chipping resistance. The thickness of the urethane coating film 4 is adjusted so that a predetermined film thickness sufficient for the above can be obtained.

(3) Third step: Masking After the urethane coating film 4 is sufficiently dried, a masking 7 is applied to the two-tone color portion 1a as shown by a broken line in the figure, and the paint is applied at the time of intermediate coating and top coating in the subsequent step. Are prevented from adhering to the two-tone color portion 1a.

The masking 7 is the lower part 1a of the vehicle body (two-tone color part)
Only the part that covers only the lower part 1a
It can be applied very easily compared to conventional masking that covers 1b (entire color part).

(4) Fourth step: intermediate coating After the above masking 7 is applied, intermediate coating is applied to the entire color portion 1b by spraying, and the electrodeposited coating 3 of the overall color portion 1b and the two-tone color portion 1a are slightly coated. An intermediate coating film 5 is formed on the urethane coating film 4 protruding.

(5) Fifth Step: Topcoating After the intermediate coating film 5 is sufficiently dried, a topcoat coating is applied to the entire color portion 1b by spraying with a paint of a predetermined overall color, and the above intermediate coating is applied. An overcoat coating film 6 is formed on the coating film 5.

(6) Sixth Step: Masking Removal After drying the top coat film 6, the masking 7 is removed. As described above, the masking 7 of this embodiment is a relatively simple one that partially covers only the lower part 1a of the vehicle body, and this masking 7 can be easily removed.

As described above, according to the present embodiment, in the two-tone painting method for the vehicle body 1 of the automobile, after the entire vehicle body 1 is subjected to the electrodeposition coating, the urethane paint of a predetermined color different from the entire color of the vehicle body 1 is applied. Since the urethane coating with a relatively large coating thickness is applied only to the lower part 1a of the vehicle body, the thickness of the electrodeposition coating 3 and the thickness of this urethane coating 4 are combined to provide sufficient chipping resistance. It is possible to obtain a predetermined coating film thickness sufficient to secure the property.

Then, after the urethane coating is applied, a masking 7 is applied to the lower body 1a, and then a portion 1b other than the lower body 1a is applied.
On the other hand, after applying the intermediate coating, the top coating is applied using the paint of the entire color.
Is a relatively simple one that partially covers only the lower part 1a of the vehicle body. As a result, it is possible to greatly simplify the masking construction and removal work and reduce the coating cost, as compared with the conventional case where large-scale masking is applied to the portion 1b other than the vehicle body lower part 1a.

The above-mentioned embodiment (hereinafter, referred to as the first embodiment).
Was a two-tone urethane coating, and the coating on the lower part of the vehicle body 1a consisted of only two layers, an electrodeposition coating 3 and a urethane coating 4. Can be composed of three layers.

 The second embodiment of the present invention will be described below.

First step: electrodeposition coating First, as in the case of the first embodiment, electrodeposition coating is applied to the entire vehicle body, and as shown in FIG.
12 is covered with electrodeposition coating 13.

Second step: urethane coating After the electrodeposition coating 13 is dried, urethane coating is applied only to the lower part 11a of the vehicle body to form the urethane coating 14 on the electrodeposition coating 13.

-Third step: intermediate coating After the urethane coating film 14 is sufficiently dried, an intermediate coating is applied to the entire vehicle body using a paint of a predetermined color different from the overall color of the vehicle body. That is, on the urethane coating film 14 that covers the lower portion 11a of the vehicle body, and the portion 11b other than the lower portion 11a of the vehicle body.
An intermediate coating film 15 is formed on the electrodeposition coating 13 of.

Fourth Step: Masking After the intermediate coating film 15 is dried, the same masking 17 as in the first embodiment is applied to the lower part 11a (two-tone color portion) of the vehicle body as shown by the broken line in the figure.

Fifth step: Topcoating After the masking 17 is applied, a topcoat is applied to the portion 11b other than the lower part 11a of the vehicle body using a paint of a predetermined overall color, and the topcoating 15 is overcoated. The film 16 is formed.

-Sixth step: removal of masking After the top coating film 16 is dried, the masking 17 is removed.

As described above, according to the present embodiment, after the electrodeposition coating is applied to the entire vehicle body, the urethane coating is applied only to the lower portion 11a of the vehicle body, and then the two-tone intermediate coating is applied to the entire vehicle body. Therefore, the coating film on the lower part 11a of the vehicle body is formed of three layers. As a result, compared to the case of the first embodiment in which the coating film is formed of two layers, the coating film on the lower part 11a of the vehicle body can be made thicker, and early rusting due to chipping causes a problem. It is possible to improve the sex.

Further, in the second embodiment, the normal dry type urethane paint is used for the urethane coating in the second step. In the case of this dry type urethane paint, when applying it on the urethane coating film in the subsequent process, in order to ensure adhesion with the coating film in the subsequent process, the urethane coating should be applied prior to the coating in the subsequent process. The membrane needs to be thoroughly dried. For this reason,
There is a drawback that the cycle time of the painting process becomes long.

This problem can be solved by using a wet type urethane paint instead of the dry type urethane paint. In the case of this wet-type urethane paint, even if the urethane coating film is in an undried state and coating is performed in a subsequent step, sufficient adhesion between the coating films can be ensured. Therefore, since the drying process is not required, the cycle time of the coating process can be shortened.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a car body steel sheet and a coating film shown by cutting the car body of FIG. 2 along the line “X”-“X” in order to explain the two-tone coating method according to the first embodiment of the present invention. Explanatory drawing, FIG. 2 is a side view of a car body painted by the two-tone painting method according to the first embodiment of the present invention, and FIG. 3 is a side view of the two-tone painting method according to the second embodiment of the present invention. FIG. 4 is a cross-sectional explanatory view of a vehicle body steel sheet and a coating film, and FIG. 4 is a cross-sectional explanatory diagram of a vehicle body steel sheet and a coating film for explaining a conventional two-tone coating method. 1 …… Car body, 1a, 11a …… Bottom body, 1b, 11b ……
Parts other than the lower part of the car body, 3,13 …… Electrodeposition coating, 4,14 …… Urethane coating, 5,15 …… Intermediate coating, 6,16 …… Top coating.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Yoshizaki 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Corporation (56) References JP-A-60-58270 (JP, A) JP-A-61 -93873 (JP, A) JP-A-61-167477 (JP, A)

Claims (1)

(57) [Claims] 1. A two-tone coating method for painting a lower part of a vehicle body with a color different from the color of the entire vehicle body. Apply a urethane coating of a predetermined color different from the overall color of the vehicle, then apply an intermediate coating to at least the parts other than the lower part of the vehicle body, and then apply the intermediate color to the parts other than the lower part of the vehicle body. A two-tone painting method characterized by applying a top coat.