JPH04277054A - Masking sheet for two-color coating and usage thereof - Google Patents

Abstract

PURPOSE:To eliminate parting inferiority by preventing the generation of the blister caused by the bubble of a solvent generated around a masking sheet even when one process of baking and curing is omitted by volatilizing the residual solvent through a vent hole 12 by peeling off the release sheet of the masking sheet after the coating with a next color to perform baking and curing even when the solvent remains on the coated surface of the first color because the baking and curing of coating material having the first color is performed at low temp. in conformity with a primer at the time of two-color coating. CONSTITUTION:A masking sheet 9 for two-color coating is constituted of a sheet like masking base material 10 having an adhesive 14 applied to the rear thereof and the release paper 15 bonded to the surface thereof and vent holes 12 for evaporating a solvent from a coated surface of a first color are perforated in the masking base material 10 in a dispersed state.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention applies a primer, a first paint color, and a second paint color to an object to be painted, such as a urethane bumper for an automobile, and when baking and curing the paint, the first
This invention relates to a masking sheet for two-color painting that is attached to areas where the paint color is exposed, and a method for using the same in two-color painting.

0002

[Prior Art] Fig. 6 shows a method in which a urethane bumper 1 as shown in Fig. 4 is coated with a primer 2, and then a paint 3 of a first color is applied.
and a conventional process for performing two-tone color painting using the paint 5 of the second color. That is, the urethane bumper 1 (A in the same figure) is coated with the primer 2 (B in the same figure) and baked and hardened at 80°C. Next, apply paint 3 of the first color (C
), bake hardened at 120°C. Furthermore, a masking tape 4 is applied to the area where the first paint 3 is to be exposed (D in the same figure), and a second paint 5 is applied (E in the same figure) and baked and cured at 120°C. Finally, by peeling off the masking tape 4 (FIG. F), the first paint color is exposed and the urethane bumper 1 is made into a two-tone color.

0003

In other words, the baking hardening process is required three times in total for each coating, and the processing time is correspondingly increased. Therefore, in order to omit the bake hardening process,
If you attempt to bake and harden Primer 2 and the first color paint together at 80°C, which is compatible with Primer 2, the solvent will leak onto the surface of the first color, which was treated at a lower temperature. There are remaining issues. In this state, when the second paint color is applied and cured by baking, the residual solvent of the first paint 3 bubbles up from around the masking tape 4 during the process, as shown in FIG. 5A. When the first paint 3 is transferred to the second paint 5, the second paint 5 bulges or bulges around it. Therefore, if the masking tape 4 is peeled off after completion of baking and hardening, a poor cutoff, or so-called burr, will occur, as shown in FIG. 5B.

[0004] In view of these points, the present invention improves the coating quality during two-color coating in which a primer with a relatively low baking hardening temperature is applied prior to sequentially applying two-color coatings to the object to be coated. An object of the present invention is to provide a masking sheet capable of shortening the baking processing time without impairing the process. Another object is to provide a method of using this masking sheet.

[0005]

[Means for Solving the Problems] In order to achieve this purpose, the masking sheet for two-color painting according to the present invention includes a sheet-like masking base material coated with an adhesive on the back side, and an adhesive adhesive on the surface of this base material. The masking substrate, which is composed of a release paper and coated with an adhesive, has vent holes dispersed therein for evaporating the solvent from the coating surface of the first coating color to which the back side of the substrate is bonded. It is characterized by being perforated with.

[0006] Prior to sequentially applying the first and second paint colors to the object to be painted using such a masking sheet for two-color painting, a primer having relatively low baking hardening temperature characteristics is applied. The method used when performing two-color painting is to apply a primer to the object to be painted, apply a paint of the first paint color including the first paint color, and apply a paint of the first paint color that is compatible with this paint color. Baked and cured at a temperature lower than the temperature and compatible with the primer, a masking sheet is pasted on the first paint color, and a second paint color is further painted, and after this painting, the release paper of the masking sheet is removed. It is peeled off and cured by baking at a temperature compatible with the second color paint.
After this baking hardening, the masking base material of the masking sheet is peeled off.

[0007]

[Operation] When the release paper is removed after the masking sheet of the second color is applied to the masking sheet pasted on the first color, the final color will be removed during the baking hardening process of the second color. Residual solvent evaporates through the vents in the masking substrate that is removed.

[0008]

[Embodiment] Fig. 1 shows a masking sheet 9 according to an embodiment of the present invention, which includes a sheet-like masking base material 10 made of PVC having a normal thickness of, for example, 0.04 mm and having an adhesive 11 applied to the back side. , a synthetic resin release paper 15 coated with an adhesive 14 and pasted on the surface of the masking base material 10
It is composed of. As shown in FIG. 2, the masking base material 10 is provided with ventilation holes 12 for evaporating the solvent, each having a diameter of about 1 mm, for example, at a density of about 10 to 15 holes/cm@2. Adhesive 11 is adhesive 1 of release paper 15
It is selected so that the adhesive force is stronger than that of 4. The masking base material 10 can also be formed into a tape shape and wound around a roller, and then rewound and cut into a required length when used.

Next, the case where the masking sheet 9 thus constructed is used for two-tone color painting of the urethane bumper 1 as shown in FIG. 4 will be described with reference to FIG. 3. First, apply primer 2 to urethane bumper 1 (A in the same figure).
(B in the same figure). Next, the paint 3 of the first color is applied widely to the first color portion 3a to be painted with the first color (C in the same figure). After the coating, it is baked and hardened at a temperature lower than 120°C, which is suitable for paint 3, and 80°C, which is suitable for primer 2. A masking sheet 9 is pasted on the first painted portion 3a (D in the same figure). Then, the area to be painted with the second color is painted with the paint 5, and at this time, the surface of the masking sheet 9 is also painted (E in the same figure). After this coating, the release paper 15 of the masking sheet 9 is peeled off (FIG. F). Since the adhesive force of this release paper is set to be weaker than that of the masking base material 10, the masking base material 10 is not peeled off.

[0010] Subsequently, the coating material 5 of the second color is baked and cured at a temperature of 120° C. (FIG. G). During this process, the solvent remaining on the painted surface of the first color paint 3 due to baking hardening at a low temperature evaporates through the ventilation holes 12 of the masking sheet 9 and escapes from its surroundings. Since the masking base material 10 is attached, the surface of the first painted portion 3a is protected. Therefore, after this baking hardening, the masking base material 1 of the masking sheet 9
By peeling off the 0 (H in the same figure), the first
The painted portion 3a is exposed.

The present invention can be applied to various objects to be coated with two-tone coating after coating with polypropylene bumpers or other polymers that are baked and hardened at relatively low temperatures.

0012

As described above, according to the masking sheet of the present invention, when performing two-color painting, by baking and curing the paint of the first paint color at a low temperature, compromising the primer,
Even if solvent remains on the painted surface of the first color, after applying the next color, the release paper of the masking sheet is removed and baked to harden, allowing the residual solvent to volatilize through the ventilation holes of the masking base material. . As a result, even if one step of baking hardening is omitted, blistering caused by solvent bubbles will not occur around the masking sheet, and there will be no defective parting. In other words, even if the bake hardening process is omitted, the coating film can be thickened.
Paint quality can also be improved. There is no problem of peeling of the masking sheet due to blisters, etc., and since the masking sheet base does not require particularly strong adhesive strength, staining of the coating film due to the adhesive can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a masking sheet according to an embodiment of the present invention.

FIG. 2 is a perspective view of the base material of the same masking sheet.

FIG. 3 is a diagram illustrating a two-color painting process using the same masking sheet.

FIG. 4 is a cross-sectional view of a urethane bumper painted in the same two-color painting process.

FIG. 5 is a diagram illustrating problems in the conventional two-color painting process.

FIG. 6 is a diagram illustrating a painting process using a conventional two-color painting masking sheet.

[Explanation of symbols]

1 Urethane bumper 2 Primer 3 First paint 5 Second paint 9 Masking sheet 10 Masking base material 11, 14 Adhesive 12 Ventilation hole 15 Release paper

Claims (2)

[Claims] Claim 1: A primer, a paint of a first paint color, and a paint of a second paint color are sequentially applied to an object to be painted, and when the paint is baked and cured, a second paint is attached to the painted surface of the first paint color. A masking sheet for color painting is composed of a sheet-like masking base material whose back surface is coated with an adhesive, and a release paper adhered to the surface of this base material, and the masking base material coated with the adhesive is The masking sheet for two-color painting is characterized in that vent holes are perforated in a dispersed state for evaporating the solvent from the painted surface of the first painted color to which the back surface of the base material is adhered. Claim 2: A claim for performing two-color painting by applying a primer having a relatively low bake-hardening temperature characteristic before sequentially applying the first and second paint colors to the object to be painted. The method for using the masking sheet for two-color painting according to Item 1, wherein the object to be painted is coated with a primer, and the first paint color is applied to the object including the first paint color, and Baking and curing at a temperature lower than the temperature compatible with the color paint and compatible with the primer, pasting the masking sheet on the first paint color part, and further painting with a second paint color, and After this coating, the release paper of the masking sheet is peeled off, and the second coating color is baked and cured at a temperature suitable for the paint, and after this baking and curing, the masking base material of the masking sheet is peeled off. How to use a masking sheet for painting.