JP3468490B2 - Painting masking method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating parting masking method for forming a parting groove in a resin molded part so as to prevent paint from adhering to the inside of the parting part when coating a resin part. The present invention relates to a masking method for a paint closeout, in which a masking jig can be easily and surely attached to an object to be painted, and a clear paint cutout line can be set at the back of a cut groove without blurring the boundary of the masking. It is a thing.

[0002]

2. Description of the Related Art For example, resin bumpers for automobiles are usually painted in the color of the vehicle body. In this case, for example, around the air intake port of the bumper or the lamp mounting portion,
In some cases, the material is masked so that the paint does not adhere to the surface, and then the coating is applied to leave the surface of the material as it is.

As an example of such a masking method,
In Japanese Patent Laid-Open No. 5-200337, a heat-resistant film laminated on the surface side of a bumper having an opening is brought into close contact with the peripheral edge of the opening of the bumper by blowing or sucking air, and then the film is bumped by a cutter. There is disclosed a method of masking the peripheral portion of the opening of the bumper by cutting around the opening of the bumper.

Further, as shown in FIGS. 3 (a) and 3 (b), a parting groove 101 is formed in advance around the coating-prohibited portion 100a of the resin bumper 100 where the paint is not desired to adhere, and the parting groove 101 is formed. A method for preventing the paint from adhering to the coating prohibited portion 100a by attaching the masking jig 102 to the bumper 100 by locking the flange 102b of the resin masking jig 102 to 101 and applying the coating in this state. Is also in practical use.

[0005]

However, in the masking method described in the above publication, a vacuum pump or a compressed air pump for bringing the resin film into close contact with the surface side including the opening of the bumper, and the film around the opening of the bumper. Not only does it require a cutter that heat-welds and cuts, increasing the size of the equipment and increasing equipment costs, but the resin film is adhered to the bumper surface using the opening, so it is not the peripheral area of the opening. Has the drawback that it cannot be applied to.

On the other hand, in the masking method in which the resin masking jig 102 is fitted into the locking groove 101 of the bumper 100, the jig can be mounted easily and the masking work time can be shortened, but the masking jig 102 and the bumper 100 are not required. There is a drawback that the state of close contact with is not always good.

That is, the resin bumper 100 is usually molded from a resin material such as PP (polypropylene) or urethane by injection molding or RIM molding (reaction injection molding). Since it is necessary to provide a gradient, the angle θ between the side surface of the parting groove 101 and the front surface of the coating prohibited portion 100a cannot be set to 90 ° or less.

On the other hand, regarding the masking jig 102,
Since the actual bumper 100 is used for raising, the main body 102a of the masking jig 102 and the flange 10
The angle formed by 2b is also formed to be the same as θ.

Therefore, when the masking jig 102 is set on the bumper 100, the flange portion 102b becomes parallel to the side surface of the parting groove 102, and the flange portion 102b is formed.
It cannot be said that a slight gap is generated between the tip of the and the side wall of the parting groove 101, and some paint mist does not enter. In such a case, the painted surface and the masking surface (painted Since it is not possible to make the boundary line with the forbidden part) clear, that is, the parting line, in the case of coating with a high required level of quality, there is no choice but to perform tape masking instead of such a masking jig 102. However, there is a problem that the working time is greatly increased and the cost is increased, and solving these problems has been a problem in the conventional masking method using a masking jig.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional coating masking method, and the masking work is easy and requires no working time without using a complicated device. It is an object of the present invention to provide a masking method capable of obtaining a clear parting line.

[0011]

According to a first aspect of the present invention, there is provided a masking method for parting a paint of a resin molded part, wherein a main part of a masking jig is provided in a parting groove formed around a coating prohibited part of the resin molded part. The angle formed by the main body of the masking jig and the flange when setting the parting line for the paint by preventing the paint from adhering to the prohibited part by locking the flanges that extend from the edge opposite each other. Is 70 ° or less, and the tip portions of the flange portions that extend in opposition to each other are elastically deformed outward and locked in the cut-out groove so that the tip portion of the flange portion is closely adhered to the side surface of the cut-out groove. The present invention is characterized in that the cut line is set at the back of the cut groove, and the structure of such a masking method for paint cutoff is used as means for solving the above-mentioned conventional problems.

Further, in the embodiment of the masking method for parting off the coating of the resin molded part according to the present invention, as described in claim 2, the masking jig flange portion of the parting groove is locked so that the parting off the coating is completed. The depth of the groove side surface on the side where the line is formed is 4 to 5 mm, the bottom width of the parting groove is 2 to 3 mm, and the extension length of the masking jig flange portion from the jig body portion is 3.5. To 4.5 mm. Furthermore, as described in claim 3, the distance from the tip of the flange portion of the masking jig to the bottom surface of the parting groove can be 0.5 mm or more.

[0013]

In the masking method for parting off the coating of the resin molded part according to the present invention, the masking jig extends from the edge of the main body portion so as to face each other and is locked in the parting groove formed in the resin molded part. Since the angle between the flange and the masking jig body is 70 ° or less,
Simply attach the masking jig to the parting groove of the resin molded part, and the masking jig will not fall off from the resin molded part that is the object to be coated, and the tip of the flange will elastically deform to completely adhere to the side surface of the parting groove. It is possible to prevent the blurring of the parting line due to invasion of paint mist and to make the parting line sharper without performing complicated masking processing with a complicated device or masking tape. Very good effect.

In a masking method according to a second aspect of the present invention, which is a masking method for parting a paint of a resin molded part, a masking jig flange portion of a parting groove is locked to form a parting line for coating. The depth of the side surface of the groove is 4 to 5 mm, the bottom width of the parting groove is 2 to 3 mm, and the extension length of the flange from the masking jig body is 3.5 to 4 mm. Since it is set to 0.5 mm, the paint parting line is set in the back of the parting groove, so even if the parting line becomes a little unclear, it will be difficult to see from the outside, and it is possible to prevent deterioration of the commercial property. It is possible to increase the adhesion of the masking jig to the parting groove, and more effectively prevent the jig from falling off and blurring the parting line.

Also, in the coating parting masking method according to the third aspect of the present invention, the distance from the tip of the flange of the masking jig to the bottom surface of the parting groove is 0.5 mm or more. The paint does not bridge with the bottom part of the parting groove, and it is possible to prevent the coating film from peeling off when the masking jig is removed from the resin molded part that is the object to be coated.

[0016]

According to the masking method for parting off the coating of the resin molded part according to the present invention, the extension angle of the flange portion of the masking jig which is locked in the parting groove formed in the resin molded part is 70.
The adhesive strength of the masking jig is improved by this, the invasion of the paint mist to the back side of the masking jig is prevented, and the coating parting line becomes clear. In this case, as an embodiment, as described in claims 2 to 3, the depth and width of the parting groove formed in the resin molded part,
It is desirable that the extension length of the masking jig flange portion be made larger than that of the conventional one, and that the distance from the tip of the flange portion of the masking jig to the bottom of the parting groove be a predetermined value or more.

That is, in a preferred embodiment, the depth of the parting groove, that is, the depth of the groove side surface on the side where the masking jig flange is locked to form the coating parting line is set to 4.
The range of ~ 5mm is that the depth of the groove side surface is 4
If the width of the bottom of the groove is less than 2 mm or if the width of the bottom of the groove is less than 2 mm, the parting part of the coating becomes easy to see, and if the parting line becomes unclear, the appearance of the coating deteriorates and the depth of the groove side surface becomes 5 mm. This is because when the width exceeds the groove width and when the groove bottom width exceeds 3 mm, the paint does not reach the bottom of the parting groove and the coating film is apt to be insufficient on the groove bottom. Moreover, the extension length of the masking jig flange is 3.5 to 4.5 mm.
The reason is that if the length of the flange is less than 3.5, the coating parting line is formed near the surface of the object to be coated (resin molded part), so the coating parting part is easily visible. As a result, the coating appearance tends to deteriorate, and sufficient adhesion to the groove side surface cannot be obtained. Conversely, when it exceeds 4.5 mm, the flange tip and the parting groove bottom are related in relation to the parting groove depth. This is due to the fact that a bridge of paint is formed between them and the paint easily peels off when the masking jig is removed.

Also in the embodiment, the distance from the tip of the flange portion of the masking jig to the bottom of the parting groove is 0.5.
If the distance is less than 0.5 mm, a bridge of paint is likely to be formed between the tip of the flange and the bottom of the parting groove, and the paint peels off when the masking jig is removed. Because it becomes easier.

In the present invention, the angle formed by the masking jig main body portion and the flange portion is set to 70 ° or less. When the angle exceeds 70 °, sufficient adhesion cannot always be obtained. It depends.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

Example of the Present Invention FIG. 1 (a) is a sectional view showing a masking procedure of a resin bumper for an automobile as an example of a coating masking method according to the present invention.

A parting groove 2 is formed around the paint-inhibited portion 1a of the bumper 1 shown in the drawing. The size of the parting groove 2 will be described later as shown in an enlarged view in FIG. 1 (b). The depth d1 of the side where the flange part 3b of the masking jig 3 is locked to form the coating parting line, that is, the side of the coating prohibited part 1a is set to 4 mm, and the bottom width w1 is set to 2 mm. Further, a draft angle is formed in the parting groove 2 in consideration of die cutting at the time of molding, and the angle α of the groove side surface with respect to the bumper front surface is 93 °.

On the other hand, the masking jig 3 is made of resin, and as shown in FIG. 1 (b), the main body portion having a shape substantially corresponding to the shape of the coating prohibited portion 1a of the bumper 1. 3a and a flange portion 3b extending from an end edge portion of the main body portion 3a, and an extension angle β of the flange portion 3b.
Is 70 ° and the extension length f1 is 3.5 mm.

Prior to painting, the masking jig 3 having the above-described shape and dimensions is attached to the bumper 1 by engaging its flange portion 3b with the parting groove 2 of the bumper 1 as shown by a virtual line in the drawing. , The painting prohibited section 1a
Hide. At this time, the flange portion 3 of the masking jig
As described above, since the angle β formed by the jig main body portion 3a is 70 °, b is elastically deformed outward when locked in the parting groove 2, and as a result, the side surface of the parting groove 2 is formed. The setting force for the masking jig 3 is increased, and the masking jig 3 is prevented from falling off the bumper 1.

When the bumper 1 with the masking jig 3 mounted thereon was painted, the paint was prevented from adhering to the paint-inhibited portion 1a, and the portion could be left as it was as the material background. At this time, since the flange portion 3b of the masking jig 3 is firmly adhered to the side surface of the parting groove 2 by elastic deformation, it is possible to completely prevent the paint mist from entering the back surface side of the masking jig 3 I was able to get a good paint line. Further, since the distance between the bottom surface of the parting groove 2 of the bumper 1 and the tip of the flange portion 3b of the masking jig 3 is 0.5 mm (d1 -f1),
The paint does not bridge between the bottom surface of the parting groove 2 and the flange portion 3b, and the bumper 1 of the masking jig 3
The paint did not peel off when it was removed.

Comparative Example In order to confirm the effect of the coating masking method according to the present invention, a resin bumper having a conventional cutout groove is masked using a conventional masking jig, and then the above-mentioned steps are performed. The same coating as the example was applied.

That is, FIGS. 2A and 2B are sectional views showing the dimensions of the parting groove and the shape of the masking jig in the conventional masking method.
00, the size of the parting groove 101 is set to a depth d2 of 2 mm on the side where the flange part 102b of the masking jig 102 is locked and the coating parting line is formed. The bottom surface width w2 and the angle θ of the groove side surface with respect to the bumper front surface are 2 mm as in the above embodiment.
And 93 °.

On the other hand, regarding the masking jig 102,
The extension length f2 of the flange portion 102b is formed to be 1.5 mm, and the extension angle of the flange portion 102b is equal to the angle θ and is 93 °.

After the masking jig 102 having the above-described shape is mounted on the bumper 100, the same coating as that in the above-mentioned embodiment is performed. As a result, although the paint can be prevented from adhering to the coating prohibited portion 100a, the masking jig 102 is prevented. Since a slight amount of paint mist entered through the minute gap G formed between the flange portion 102b and the side wall of the parting groove 2, it was not possible to obtain a clear paint parting line.

[Brief description of drawings]

FIG. 1 (a) is a cross-sectional explanatory view showing the shapes of an automotive resin bumper and a masking jig used in an example of a coating masking method according to the present invention. (B) It is an expanded sectional view showing the part near the parting groove of the bumper shown in FIG. 1 (a).

FIG. 2 (a) is a cross-sectional explanatory view showing the shapes of a conventional automotive resin bumper and a masking jig used as comparative examples. (B) It is an expanded sectional view showing the part near the parting groove of the bumper shown in FIG. 2 (a).

FIG. 3 (a) is a cross-sectional explanatory view showing a conventional masking procedure for an automobile resin bumper. (B) It is an expanded sectional view which shows the vicinity of the parting groove of the bumper shown in FIG. 3 (a).

[Explanation of symbols]

1 Bumper (resin molded parts) 1a Painting prohibited section 2 parting groove 3 Masking jig 3a main body 3b Flange part

Front page continuation (72) Inventor Kiyoshi Koyanagi 2-55-3 Futatsunuma, Yoshikawa-shi, Saitama Seiyaku Kogyo Co., Ltd. (72) Hiroaki Kato 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Sanko Co., Ltd. (56) Reference JP-A-7-88429 (JP, A) JP-A-8-127894 (JP, A) Actual exploitation Sho-57-169478 (JP, U) Actual exploitation Sho-62-190661 ( (58) Fields surveyed (Int.Cl. ⁷ , DB name) B05D 1/32 B05B 15/04 102

Claims (3)

(57) [Claims] 1. A paint applied to a coating-prohibited portion by locking flanges extending from the end edge of the main body portion of the masking jig so as to face each other in a parting groove formed around the coating-prohibited portion of the resin molded part. When setting the paint parting line by preventing the adhesion of the paint, the angle between the body of the masking jig and the flange should be 7
The end portions of the flange portions, which are 0 ° or less and extend opposite to each other, are elastically deformed outwardly and locked in the cutout groove so that the tip portion of the flange portion is closely adhered to the side surface of the cutout groove. A masking method for coating parting of resin molded parts, which is characterized in that it is set inside the parting groove. 2. The depth of the groove side face on the side where the coating parting line is formed by locking the flange of the parting groove masking jig is 4 to 5 mm, and the bottom width of the parting groove is 2 to 3 mm. 2. The masking method for parting off painting of a resin molded part according to claim 1, wherein the extension length of the masking jig flange portion from the jig main body portion is 3.5 to 4.5 mm. 3. The mask for coating parting of a resin molded part according to claim 1 or 2, wherein the distance from the tip of the flange of the masking jig to the bottom surface of the parting groove is 0.5 mm or more. Method.