JPS6034814A - Pattern coating method of synthetic resin product - Google Patents

Abstract

PURPOSE:To foam an even pattern paints layer without the difference in level on the surface of a pattern-portion by a method in which after a pattern has been printed on the cavity surface of a mold with first paints, the upper surface of said pattern in the cavity is further coated with second paints in the method of wet on wet. CONSTITUTION:A stamp 16 is arranged at a specified position in the cavity 13 of a female mold 11 constituting a mold 10 for-resin molding. A sponge material 18 is pushed onto the cavity surface of the female mold 11, introducing compressed air into a housing 19 by opening a partition valve 27. Consequently, the paints contained in the sponge material 18 is transferred onto the female mold 11 and a pattern 28 is printed. Next, this upper surface is coated with the paints different from said paints in the method of wet on wet by a coating gun. Accordingly, at the paints surface being in contact with the female mold 11, a first coat 28 and a second coat 30 have no gap therebetween, and are molded continuously without the difference in level. The first coat 28 and the second coat 30 applied in the method of wet on wet are cured as one coat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for painting synthetic resin products, particularly to an improvement in a method for painting a pattern in which the paint color is partially different.

BACKGROUND OF THE INVENTION Recent automotive bumpers are shifting from metal bumpers to resin bumpers. This is because bumpers made of synthetic resin have elasticity and are excellent in protecting the vehicle body in the event of a minor collision, as well as increasing the degree of freedom in shaping. There is a tendency for resin bumpers to be colored to improve their decorative properties, and a so-called mold coating method has been proposed as a coloring method that completes painting at the same time as molding the resin product. . This coating method involves spraying paint onto the cavity surface of a resin mold to form a paint film, and then injecting the resin material to complete the modeling and painting of the resin product at the same time. however,
Even with this coating method, if a pattern is to be painted, an arbitrary pattern can be obtained by using a masking member 3 such as tape, paper, or a jig on the coating film 2 of the resin product 1, as shown in FIG. Masking was applied as shown, and the second paint was further applied to the areas that were not covered using Paint 4.

For this reason, a masking process and one culm of painting are still required, resulting in poor work efficiency. In addition, in addition to the masking member, a coating booth and a coating machine are required, so there is a problem in that equipment costs and material costs are high. Furthermore, there is a problem that a difference in level occurs between the first coating film 2 and the second coating film 5.

The present invention has been made by focusing on these conventional problems, and is a synthetic resin product that can be easily and quickly pattern-painted at low cost! The purpose of this is to provide a coating method in which a paint is applied to the inside of a mold for molding a synthetic resin product, a resin material is injected, and the surface of the resin product is coated at the same time as the resin product is molded.
After printing an arbitrary pattern on the cavity surface of the mold with the first paint, a second paint is further applied wet-on-wet into the cavity to create a flat pattern with no steps on the surface of the pattern. It is designed to form a paint layer.

The method of the present invention will be explained in detail below based on an embodiment shown in the drawings.

FIG. 2 shows a resin mold for carrying out the pattern coating method of the present invention. This mold 10 includes a female mold 11 and a male mold 1.
2 constitute a sealed cavity 13, and a resin material is injected into the cavity 13 from the resin injection port 14 of the male mold 12 to mold a resin product. Furthermore, the mold 10 is configured to create an environment suitable for molding the resin material within the cavity 13. For example, using polyurethane as the resin material, reaction index molding (RI)
In the case of M), the mold 10 has a built-in cooling pipe (not shown) so that the temperature can be controlled to adjust the polymerization reaction. The urethane production reaction is extremely exothermic, and to control this intense reaction heat, cooling water is passed through the cooling pipe. However, the heat of reaction causes the paint applied to the cavity 13 to harden and adhere to the surface of the resin product. The solvent or moisture volatilized from the paint is released from the gas vent hole (not shown) in the mold 10 along with other gases. If the resin is another thermosetting resin and needs to be heated, the mold 10 has a built-in heating device, and the heat cures the paint at the same time.

FIG. 3 also shows an apparatus for printing paint onto the female mold 11 of the mold 10 described above.

This printing device 15 consists of a movable stamp 16 for impregnating the paint and a paint supply device 17 for impregnating the stamp 16 with the paint. The stamp 16 is made up of a spongy material/sponge body 18 containing paint and a housing 19 that surrounds and elastically supports it, and the sponge body 18 is pushed out of the housing 19 by introducing compressed air into the housing 19. It is set in. Here, the sponge body 18 forming a desired pattern shape is adhered to and reinforced by a reinforcing plate 20, and is movably attached to the housing 19 via a spring 21. On the other hand, a pressure supply source (not shown) is connected to the housing 19 and is provided so that compressed air can be introduced by operating a gate valve 27. Therefore, normally the spring 21
The sponge body 18 drawn into the interior of the sponge body 9 is pushed out of the housing 19 at the same time as the compressed air is introduced, and is pressed against the object to be coated, thereby transferring the impregnating paint thereon.

The paint supply device f17 includes a paint tank 22 that stores a certain amount of paint to be used, a circulation path 23 and a circulation pump 24 that take out the paint in the tank 22 from the lower part and return it to the upper part. The circulation path 23 has an opening 25 in which the stamp 16 is fitted, and forms a closed circulation cycle when the stamp 16 is fitted. The opening 25 of the circulation path 23 is intersected by the housing 19 of the stamp 16, and has a frontage shape that corresponds to the bottom shape of the housing 19 and has approximately the same size. For example, when the bottom of the housing 19 is formed into a slope as in this embodiment, the opening 25 is formed by a corresponding slope.

A sealing member 26 made of an elastic material is attached to the entire circumference of the opening 25 to prevent paint from leaking.

The paint drawn out from the paint tank 22 by the circulation pump 24 comes into contact with the sponge body 18 of the stamp 16 forming a part of the circulation path 23 while flowing through the circulation path 23, and infiltrates the sponge body. The paint pump 24 stops driving when the stamp 16 is separated from the opening 25 of the circulation path 23 and returns the paint to the tank 22. Moreover, a normal pipe is sufficient for the portion of the circulation path 23 except for the opening 25 and its vicinity.

Pattern painting is carried out as follows using the resin molding mold 10 and printing device 15 configured in this manner.

First, as shown in FIG. 4(a), the stamp 16 is applied to the opening 25 of the circulation path 23 of the paint supply device 17 to seal the circulation path 23, and then the circulation pump 24 is operated. The paint flowing through the circulation path 23 comes into contact with the sponge body 18 of the stamp 16 and soaks into it. When the sponge body 18 of the stamp 16 is sufficiently soaked with paint, the stamp 16 is removed from the circulation path 23 of the paint supply device 17. At this time, the circulation pump 24 stops driving, returns the paint to the tank 22, and prepares for the next operation.

Next, as shown in FIG. 4(b), a stamp 16 is placed at a predetermined position in the cavity 13 of the female mold 11 constituting the resin mold 10. Then, gate valve 2
7 is opened to introduce compressed air into the housing 19, and the sponge body 18 is pressed against the cavity surface of the female mold 11.

Then, the paint contained in the sponge body 18 is transferred to the female mold 11.
The pattern is printed. At this time, the sponge body 18
Since the housing 19 surrounding the masking jig functions as a masking jig, a beautiful and clear parting line can be obtained. Thereafter, the stamp 16 is again installed in the circulation path 23 of the paint supply device 17 and immersed in the circulating paint, in preparation for the next operation. Of course, it goes without saying that an appropriate amount of mold release agent is applied to the mold 10 prior to printing the paint.

Next, as shown in FIG. 4(C), a paint different from the first paint film 28 printed on the surface constituting the cavity 13 of the female mold 12 is wet-on using a paint gun 29. - Paint wet. The second coating film 30 obtained by this coating covers the first coating film 28 and is applied to the female mold 1.
It is formed over the entire surface constituting the cavity 13 of 1.

Therefore, the first coating film 28 on the surface in contact with the female mold 11
and the second coating film 30 are formed continuously without any gaps or steps. Moreover, the first coating HIA2B and the second coating film 30 applied wet-on-wet are cured as one coating film. Although not shown, the second coating 1!30
It is not necessary to cover the entire area of the first coating film 28. It is sufficient to form the second Al15!30 so as to overlap at least near the periphery of the first coating l1128. Also,
Formation of the second coating 30 may rely on a printing method similar to that used for the first' coating 28.

Thereafter, the female mold 11 and the male mold 12 are combined and clamped, and the resin material 31 is injected into the cavity 13 from the resin injection port 14. Then, it is heated m degrees υ'Jllll so as to cause a predetermined polymerization reaction or curing reaction to form a resin product. The material resin 31 does not fill the original cavity 13, but instead forms a second coating film 30 formed on the surface of the female mold 11.
and the male mold 12 to fill the gap.

Therefore, the material resin 31 is the first one on the surface side. 2nd coating pA
The resin product 32 is cured together with 28°30. That is, the coating of the resin product 32 molded within the mold 10 is completed at the same time as the modeling. After the molding is completed, the resin molded product 32 is removed from the mold 10. This resin molded product 32
For example, automotive resin bumper L-capture...l, f-+
Mid-term break IQ1 /7'l W Spring Resistance AEA101L' It is obtained with the surface coated with the desired pattern.

As is clear from the above explanation, the pattern coating method of the present invention applies a
After printing an arbitrary pattern on the cavity surface of the mold using the above paint, a second paint is applied wet-on-wet into the cavity to form a flat pattern paint layer with no steps on the surface of the pattern area. After the resin material is formed, a resin material is injected and a pattern is painted on the surface of the resin product at the same time as the resin product is molded. Therefore, the masking work and the painting work after resin molding, as well as the jigs and tools necessary for these works, are required.
No equipment is required, and pattern painting can be done quickly and easily at low cost. Further, according to this pattern coating method, automation is possible because there is no masking work that requires skill, and since the coating is repeated within the mold, there is no difference in level between the different coating films that make up the pattern.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional pattern coating method for synthetic resin products, and FIGS. 2 and 3 are schematic cross-sectional views of a resin mold and printing apparatus used in the pattern coating method for synthetic resin products according to the present invention. Schematic sectional view of FIG. 4(a)-(
e) is an explanatory diagram showing the working state of the pattern coating method for synthetic resin products according to the present invention. 10... Mold, 11... Female mold, 12... Male mold, 13... Cavity, 15... Printing device, 1
6... Stamp, 28... First coating film, 30...
2nd coating film, 31...Material resin, 32...Resin product. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] In a coating method in which a paint is applied to the cavity of a mold for molding a synthetic resin product, a resin material is injected, and the surface of the resin product is painted at the same time as the resin product is molded. A synthetic resin product characterized in that after printing on the surface, a second paint is applied wet-on-wet into the cavity to form a flat patterned paint layer with no steps on the surface of the patterned area. How to paint a pattern.