JPS6034810A - Mold for resin molding used for mold coating process - Google Patents

Abstract

PURPOSE:To cause a parting line not to deviate by a method in which the beads for parting line which project into the cavity at the mold surface of a mold for resin molding and define the boundary of coating, is provided, and masking is achieved along this beads for parting line. CONSTITUTION:The beads for parting line project into the cavity 12 in the female mold 10 of molds. These beads for parting line constitute a part of a masking jig defining the parting line of coating, dividing a coating part from a noncoating part, and function as the guide for setting the masking jig. These beads 14 for parting are formed with the slope having a draft and height necessary for setting the masking jig 15 at the side of noncoating range at the boundary between a coating range and a noncoating range. As the masking jig 15 is formally fitted into the beads for parting, the mist of paint does not invade into the masking position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin molding mold suitable for use when molding and painting are performed simultaneously and two-tone painting is performed in the production of resin molded products.

Recently, bumpers for automobiles are mainly made of resin, which has high elasticity and absorbs shock, in order to improve the car body protection function in the event of a light collision and increase the degree of freedom in shaping.

There is a tendency for resin bumpers to be colored in order to enhance their decorative effect, and the method of applying this color by painting provides a higher aesthetic appearance than the method of directly mixing pigments into the bumper material resin. It is liked because it can be done.

In addition, rather than painting the entire surface in a negative color, exposing a portion of the resin material or painting it in a different color to achieve two-tone painting is being considered because it provides a better aesthetic effect. Of course, the same is true not only for synthetic resin molded products for automobiles, but also for two-tone painting of synthetic resin molded products that are widely used in electrical appliances and other industrial products.

Two-tone painting in the so-called molding method, in which the mold surface of a resin mold is preliminarily coated, a material resin is injected into the cavity of the mold, and molding and painting are performed simultaneously is carried out as follows. In other words, in this two-tone coating method, as shown in FIGS. 1 and 2, a jig 3 such as masking tape or paper or metal fittings is installed on the inner surface of the cavity of a resin mold 1. After masking the remaining portion with the resin material color and spraying paint over it to form a paint film 2 on the inner surface of the cavity of the mold 1, the material resin is injected into the cavity to mold and paint the resin product. At the same time, it is completed. Of course, when injecting the resin, the masking jig 3 is removed and the mold 1 is sufficiently clamped. According to this method, a paint film is not formed in the area where the masking jig 3 was installed and the base resin color remains, so a two-tone finish can be achieved.

However, this painting method has a problem in that the masking work is not easy. That is, when tape or paper is used as the masking jig 3, it is easy to bend, and unless it is carefully pasted by the worker's hand, beautiful parting lines (
Since the boundary line between the painted surface and the non-painted surface cannot be obtained, the masking work requires a considerable amount of effort, and since it is difficult to reuse the tape, etc., it becomes disposable, resulting in high costs.

Furthermore, when using a reusable metal masking jig, it is difficult to bring it into close contact with the mold without any gaps, so there is a risk that paint may enter the masking area and disturb the parting line.

The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a resin mold that can easily and quickly perform masking without disturbing the parting line. In the mold coating method, in which a resin material is injected into the cavity of a resin mold coated with a coating material to form and paint a resin product at the same time, the surface of the resin mold protrudes into the cavity and is coated with paint. A parting bead defining a boundary is provided, and masking is performed along the parting bead.

Hereinafter, the configuration of the present invention will be explained in detail based on an embodiment shown in the drawings and FIG.

FIG. 3 shows a cross-sectional view of an old model of the resin mold according to the present invention. In this mold, a female mold 10 and a male mold 11 constitute a sealed cavity 12, and a resin material is injected into the cavity 12 from a resin injection port 13 of the male mold 11 to mold a resin product. . The mold is configured to create an environment suitable for molding the resin material within the cavity 12. For example, although not shown, reaction injection molding (RIM) is performed using polyurethane as the resin material.
) In order to regulate the polymerization reaction, the mold has a built-in cooling pipe so that the temperature can be controlled. The urethane production reaction is extremely exothermic, and to control this intense reflected heat, cooling water is passed through the cooling pipe. However, this reaction heat causes the paint applied to the cavity 12 to harden.
Adheres to the surface of resin molded products. Further, the solvent, water, etc. that volatilize from the paint are released from the gas vent hole (not shown) of the mold along with the gas etc. generated during resin molding.

In addition, when using other thermosetting resins that require heating, the mold has a built-in heating device, and the heat cures the paint at the same time.

A female part 10 of the mold is provided with a parting bead 14 that projects into the cavity 12.

This parting bead 14 functions as a part of a masking jig that separates a painted part from a non-painted part and forms a parting line for painting, and also functions as a guide for installing a masking jig 15. On the other hand, this parting bead 14 is
Since it protrudes into the tee 12 and forms a groove in the resin molded product, it is not preferable to make it protrude more than necessary. therefore,
This parting bead 14 is formed to protrude to a height necessary for installing a masking jig 15 on the non-painting area side of the boundary between the painting area and the non-painting area. It should be noted that the bead 14 is formed on a sloped surface in consideration of the removal of the resin molded product.

The masking jig 15 installed along the above-mentioned parting bead 14 is like a lid that straddles the beads 14 on both sides and covers the tops of these and the unpainted part between them. The masking jig 15 of this embodiment has a parting bead 1
It has legs 16 that are inserted between the legs 16, and is made of synthetic resin or metal and has a flat plate shape. Of course, the masking jig 15 may have any shape as long as it can be installed along the parting bead 14.

Two-tone painting is carried out as follows using the resin mold constructed in this way.

First, a release agent is applied to the mold. The mold release agent is wiped off so that an appropriate amount remains. Next, female mold 1 of this mold
Masking jig 15 using parting bead 14 at 0
Set up. Then, paint of a designated color is applied to the entire inner surface of the mold from above this masking jig 15. After applying the paint, remove the masking jig 15 and remove the male mold 1.
1 and the female mold 10 and tighten them. Thereafter, raw resin is injected from the resin injection port 13 of the male die 11 until the cavity 12 is filled. At this time, the material resin is injected into the gap between the coating film 17 formed on the surface of the female mold 10 and the male mold 11 and fills the gap, so that it hardens together with the coating film 17 to form a resin product 19. becomes.

In addition, in the area to which the paint 17 is not applied, that is, the area 18 covered by the masking jig 15, the material color itself appears on the product surface. For this reason, the resin molded article 19 molded in the mold is completed with two-tone painting at the same time as modeling. For example, in the case of this embodiment applied to a resin bumper for an automobile, the coating is performed as shown in FIG. 4.

In addition, in the painting process, the masking jig 15 is fitted into the parting bead 14, so there is almost no intrusion of paint mist into the masking area, and even if it adheres to the outer surface of the parting bead 14, the molding will not be completed. Since it stays in the groove 20 of the product 19, there is no problem in terms of appearance.

As is clear from the above description, the present invention is directed to the resin used in the mold coating method, in which a resin material is injected into the cavity of a resin mold coated with a desired paint to simultaneously mold and paint a resin product. A parting bead that protrudes into the cavity and defines the coating boundary is provided on the mold surface of the mold, and masking is performed along this parting bead, so that the masking jig and the parting L'-do are easily connected. Masking can be performed without creating any gaps. Therefore, there is no infiltration of paint mist into the masking surface, and it is possible to obtain a two-tone coating with beautiful parting lines without any disturbance. Further, since the parting line is formed by the parting bead, it is always constant even if it does not depend on a skilled worker. Further, since a masking jig can be installed along this parting bead, even if the masking jig is made of metal or synthetic resin, it can be easily masked by simply fitting it, making it possible to speed up and automate the masking work.

[Brief explanation of the drawings] Fig. 1 is a work process diagram of a conventional two-tone painting method, Fig. 2 is a cross-sectional view showing the masking state when two-tone painting is performed in a mold coating method using a conventional mold,
FIG. 3 shows resin acid IQ-...mold female mold according to the present invention,
11... Mold male mold, 12... Cavity, 14
...Big brother cutting bead, 15...Masking jig. Patent applicant Nissan Motor Co., Ltd. Agent Patent attorney 8 1) Miki'A! , 2nd v!
A 3 3rd-4th WIJ

Claims (1)

[Claims] Painting protrudes into the cavity on the mold surface of the resin mold used in the mold coating method, in which a resin material is injected into the cavity of the resin mold coated with a desired paint to simultaneously mold and paint the resin product. A mold for resin molding, characterized in that a parting pea is provided to define the boundary of the parting pea, and masking is performed along the parting pea.