JPH0240261A - Multicolor painting method - Google Patents

Abstract

PURPOSE:To allow multicolor painting with one time of a finish coating stage and to improve productivity and coated surface by sticking a masking member onto an intermediate coated film and applying a base paint thereto, then stripping the coating and applying a clear paint thereon from above. CONSTITUTION:A vehicle body with which an electrodeposition painting stage ends is transported to an intermediate coating stage 1 to improve the adhesive property and weatherability of finish coated films 11, 12. The vehicle body coated with the intermediate paint is then transported to a drying device where the body is dried under the conditions of 140 deg.CX20 minutes holding. The vehicle body is transported to a masking member sticking stage 3 where the masking member 19 formed to an N shape is stuck to the prescribed position of the vehicle body. The vehicle body is then transported to a finish coating booth where a metallic base paint of a baking type paint is sprayed to the vehicle body surface by an electrostatic painter, etc. The masking member 19 is stripped and the clear paint is applied thereon from above. The vehicle body is transported to a drying device where the body is dried under the conditions of 140 deg.CX20 minutes holding. The steps of a character part 14 are substantially annihilated in the finish coated films 11, 12 with which the drying ends.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a multicolor coating method for drawing letters, patterns, etc. on the surface of a workpiece using different colors of the coating film, which reduces the number of coating processes and improves productivity. It's what I made.

(Prior art) Conventional multi-color painting methods include what is generally called two-tone painting, and what is known as a painting in which letters, etc. are locally drawn. So-called stripe tape, which is printed on a thin plate-like member made of synthetic resin such as polyester, is also used, but this is expensive due to the production process and is difficult to attach to the exterior panels of automobiles. There is a risk of theft after being stolen, and in recent years, multicolor painting has been developed that uses coatings of different colors to draw letters, etc.

As shown in Figure 6, such multi-colored painting
and the color of the character part 14 are changed,
The coating film structure is as shown in FIG. 7th
In the diagram (Δ), one electrodeposited coating film applied on the steel plate 8 as a workpiece, an intermediate coating film 10 applied on the electrocoated coating film 9, and two coats and one bake type top coating. It is composed of a first base coating film 15, a first clear coating film 16, and a second base coating film 17 and a second clear coating film 18,
After applying the first top coat 15°16 on the intermediate coat 10 and drying it, a masking member (not shown) in the shape of the letters rNJ shown in Fig. 6 is pasted at a predetermined position. This coating is obtained by applying a second topcoat 17, 18 from above, drying and then removing the masking member. Moreover, what is shown in FIG. 7(B) is an electrodeposition coating film 9 applied on a steel plate 8, which is a workpiece, similarly to the coating film described above, and an intermediate coating applied on the electrodeposition coating film 9. film 10 and a first base coating film 15 of 2-coat, 1-bake type topcoat paint.
, a first clear coating film 16, a second base coating film 17, and a second clear coating film 18. In this case, the shape of the masking member is the same as the reference numeral 13 shown in FIG.
Therefore, the color of the letter "N" after coating is the color of the first top coat 15 in FIG. 7(A), while the color of the letter "N" in FIG. 7(B) is The color is that of the second top coat 17.

Here, the two-coat one-bake type top coat is composed of a base paint that contains aluminum powder or mica flakes and is made of pigment, resin, and solvent, and a clear paint that does not contain pigment and is made of resin and solvent. This refers to a type of top coat paint in which both paints are dried simultaneously after being sprayed without a drying process.

(Problem to be solved by the invention) However, in such a conventional multi-color painting method,
It is necessary to perform the top coating process and drying process twice,
The disadvantage is that productivity decreases. In addition, a large level difference occurs on the surface of the paint film after coating is completed (normally, the base coat is 15 μm thick, the clear coat is 35 μm, and the total level difference is 50 μm).
Moreover, the end surface of the clear coating film shown in Fig. 7 is sharp,
It is also unfavorable in terms of appearance.

The present invention has been made in view of the drawbacks and problems associated with the prior art described above, and an object of the present invention is to provide multi-color coating with good productivity and good appearance.

(Means for Solving the Problems) In order to achieve the above object, the present invention applies two coats after pasting a masking member formed in a predetermined shape on the intermediate coat film that has been applied to the surface of the workpiece and dried. After applying the base paint of the 1-bake type top coat, peeling off the masking member, and spraying the clear paint of the top coat,
This is a multicolor coating method in which the base paint and the clear paint are dried at the same time.

(Function) In the present invention configured as described above, the masking member is pasted on the intermediate coating film, peeled off as soon as the base paint is applied, and the clear paint is applied over it. Multicolor painting is possible with a single overcoating process, and the clear coating film that forms the coating surface becomes smooth, resulting in a good appearance.

(Example) Hereinafter, an example of the present invention will be described as being applied to painting an automobile body with reference to the drawings.

FIG. 1 is a process diagram showing the steps of a multicolor coating method according to an embodiment of the present invention, FIG. 2 is a front view showing a coating film painted by a multicolor coating method according to an embodiment of the present invention, and FIG. The figure is a cross-sectional view taken along the line ■-■ in Figure 2, and Figure 4 is a cross-sectional view explaining changes in the coating film structure of the same example, and is common to the conventional multicolor coating shown in Figures 6 and 7. The same parts are given the same reference numerals.

First, as shown in FIG. 1, the multicolor coating method of this embodiment includes an electrodeposition coating process which is an undercoat coating process (not shown), an intermediate coating process 1, a drying process 2 of the intermediate coating paint, The process consists of a masking member adhesion process 3, a metallic base coating process 4 for the top coat, a masking member peeling process 5, a clear coating process 6 for the top coat, and a drying process 7 for the top coat. In the electrodeposition coating process, oil and dust adhering to the outer panel of the automobile body (work 8) are removed, and the surface of the steel plate is pretreated to oxidize to form a phosphoric acid film, and then paint is applied using a dipping method. This is the process of adhering approximately 15 μm1 on the vertical surface of the car body.
The film thickness is about 20 μm horizontally.

The main purpose of this electrodeposition coating is to prevent rust on the steel plates that make up the outer panels of the car body.For outer panels other than steel plates, such as synthetic resin, the electrodeposition coating process can be omitted. It is possible.

After this electrodeposition paint is applied, it is dried at a high temperature (180'
CX held for 20 minutes).

The car body that has undergone the electrodeposition coating process is transported to a sealing process, in which the joints of the parts forming the grooves of the car body are sealed in order to prevent water from entering the interior of the car and to prevent rust. Further, this car body is transported to an intermediate coating process 1, where an intermediate coating is applied in an intermediate coating booth. The intermediate coat 10 is a paint that is applied to improve the adhesion of the top coat 11 and 12 as well as weather resistance, and is necessarily a paint that has a constant color regardless of the color of the top coat. It is a membrane, and the inside of the membrane is gray.

However, with the high brightness top coat that has been developed in recent years,
In some cases, an intermediate paint colored in a predetermined color is used.

The car body is coated with intermediate paint at the intermediate painting booth.
It is transported to a drying device and dried under conditions of 140'C x 20 minutes hold. As shown in FIG. 4, the dry intermediate coating film 10 has a thickness of about 20 to 30 μm.

As is clear from the cross-sectional view of FIG. 3, the intermediate coating film 10 used in this example appears on the outer surface only through the clear coating film 12, and ultraviolet rays passing through the clear coating film 12 The composition is such that the intermediate coating film 10 does not deteriorate due to such factors. That is, the composition is as shown in Table 1, with isophthalic acid linear polyester resin having excellent weather resistance as the main component.

(Margin below) Table 1 Composition ratio (%) (Removal oil 1) Isophthalic acid linear polyester 2) Melamine 3) Epoxy 45.7 16.6 3.0 H material 1) Titanium oxide 2) Ultrafine pigment 20 .0 4.8 Additive 1) Surface conditioner 2) Others 1.4 0.5 Solvent 1) Aromatic hydrocarbon 2) Alcohol 3) Ester 6°8 0.7 0.5 Total 100.0% Next , the vehicle body is transported to a masking member adhesion step 3, and if painting is to be done in the shape of the letter rNJ as shown in FIG. 2, the masking member 19 formed in the shape of this rNJ is
Attach it to the specified position on the vehicle body. This masking member 19 may be a so-called adhesive tape coated with an adhesive on one side, and the letters rNJ can be easily formed by press-molding the outer shape 1. However, the adhesive applied to one masking member has a low surface tension, so even if clear paint is applied from above, the paint film 12
It is necessary to select materials that have less impact on

The vehicle body to which the masking member 19 has been pasted in this manner is transported to a topcoating booth, and is first coated with a 2-coat, 1-bake type metallic base paint (metallic base coating step 4). The color of this base paint varies depending on the specifications of the vehicle body, and is sprayed onto the surface of the vehicle body using an electrostatic coating device or the like having a color changing device. After applying the base paint, the masking member 1 is
9 is peeled off, masking member peeling step 5), and then a clear paint is applied thereon (clear coating step 6). This clear paint is also applied by an electrostatic coating device. The time from applying the base paint to applying the clear paint is usually around 4 minutes.If this value cannot be ensured depending on the process conditions, add acid to the base paint or add solvent to the clear paint as appropriate. All you have to do is choose. For example, if the interval between application of the base paint and application of the clear paint is short, the boiling point of the solvent mixed in the base paint may be lowered.

In this way, the base paint and clear paint, which have been coated over each other in a so-called wet-on-wet manner without a drying step, are transported to a drying device and dried under conditions of 140'C x 20 minutes. In this drying process, the viscosity of the clear paint decreases rapidly just before the crosslinking reaction occurs, and the clear paint flows so as to alleviate the step difference in the adhesion mark of the masking member 19 that has occurred in the base paint. Therefore, in the top coat film 11, 12 that has finished drying, the step difference in the character portion 14 has almost disappeared, and the top coat film 11, 12 is suitable in terms of appearance.

According to the multi-color painting method of this embodiment, letters in the color of the intermediate paint are formed on the car body surface after painting is completed, and can be done in a single top-coating process. A coating with good weather resistance can also be obtained.

FIG. 5 is a cross-sectional view illustrating changes in a coating film painted by a multicolor coating method according to another embodiment of the present invention, and is a cross-sectional view of the first embodiment and the conventional example shown in FIGS. 6 and 7. Common parts are given the same reference numerals.

In this embodiment, the color of the character portion 14 shown in FIG. 2 is set to a desired color, and 1. An intermediate coating 10 having the composition shown in Table 1 is applied, and a top coating 20 is locally applied using wet-on-wet with this coating. The top coat 20 is preferably a solid paint, and preferably a paint containing polyester resin as a main component. The intermediate coat 10 and top coat 20 thus applied are dried simultaneously in a drying step 2, and after a masking member 19 is pasted on the top coat 20, the top coat 20 is placed in the top coat booth as in the first embodiment. A two-coat, one-bake top coat of 11.12° is applied.

Therefore, in the coating film of this example configured in this way, the color of the character portion 14 becomes a desired color, for example, the color of the character portion 1
It becomes possible to select a color corresponding to the color of the coating film around 13 of 4.

In this embodiment, a specific example in which a multicolor painting method is applied to the outer panel of a vehicle body is described, but the present invention is not limited to this, and may be applied to, for example, parts attached to a vehicle body. The present invention can be applied not only to steel plate materials but also to bumpers made of synthetic resin, for example.

Furthermore, the masking member can be formed into a shape as shown in FIG. 7(B) and can be painted in multiple colors according to the present invention.

(Effects of the Invention) As described above, according to the present invention, the masking member is pasted on the intermediate coating film, and after the base paint is applied, it is peeled off, and the clear paint is applied on top of it. , it is possible to paint in multiple colors in a single overcoating process, and the clear coating film forming the coating surface becomes smooth, resulting in good appearance. Therefore, the productivity of multi-color painting is improved and an excellent painted surface can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the steps of a multicolor coating method according to an embodiment of the present invention, FIG. 2 is a front view showing a coating film painted by a multicolor coating method according to an embodiment of the present invention, and FIG. The figure is a sectional view taken along the line ■-■ in Fig. 2, Fig. 4 is a sectional view illustrating changes in the coating film structure of the same embodiment, and Fig. 5 is a multicolor coating according to another embodiment of the present invention. 6 and 7 are a front view and a cross-sectional view taken along the vu-vu line showing the paint film painted by the conventional multicolor painting method. 1... Intermediate coating process, 2, 7... Drying process, 3.
... Masking member adhesion process, 4... Metallic base painting process, 5... Masking member peeling process, 6... Clear coating process, 8... Steel plate (work) 9.
... Den@paint film, 10... Intermediate paint film, 11.15.1
7... Base coating film, 12.16.18... Clear coating film, 19... Masking member. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] After pasting a masking member formed into a predetermined shape on the intermediate coating film that has been applied to the work surface and dried, 2 coats 1
A multicolor coating method comprising applying a base paint of a bake-type top coat, peeling off the masking member, spraying a clear paint of the top coat, and drying the base paint and the clear paint at the same time.