JPS606778B2 - Manufacturing method for automotive interior parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing interior parts for automobiles, and particularly relates to a method for producing interior parts for automobiles that are resistant to discoloration even after long-term use and have a relatively strong skin. It is.

For door trims, instrument/guts, head consoles, armrests, sun/sizers, and other various interior parts for automobiles, a foam layer is generally applied to the surface of a reinforcing core material such as a board formed into the shape of the product. It is made up of laminated skin layers.

Incidentally, as passenger cars have become more popular in recent years, there has been a demand for the designs and materials of the above-mentioned interior parts to have a more luxurious feel, and on the other hand, there has also been a demand for them to be provided at low cost and in large quantities.
The texture of these interior items is mainly determined by the material of the skin layer, and the materials that make up this skin layer have conventionally been, for example, ABS resin sheets, vinyl chloride sheets, or sheet materials containing appropriate proportions of these materials. Because of its use, it had the disadvantage of lacking in feel and texture. In addition, the process of manufacturing a product using the above-mentioned sheet involves forming the sheet into a product shape by vacuum forming, etc., and then combining this sheet with a reinforcing core material that has been previously formed into the same product shape as above by press-forming, etc. They are set in both male and female foam molds, foamed resin is injected into these molds, and both molds are brought together to form a foam layer between them, and then trimmed and welded as necessary. However, such a manufacturing method requires a large number of processing steps, and when manufacturing products with complex shapes, large wrinkles tend to form on the surface due to misalignment of the sheet during foam molding, causing a decrease in yield.

On the other hand, recently, interior parts have been developed in which a delicate skin layer is integrally formed on the surface of the foam molded product by appropriately adjusting the foaming conditions of the foamable resin. Since it is easy to peel off in a state where the epidermal layer is peeled off, it cannot be used in areas that require physical strength, and its uses are naturally limited.

Here, the present applicant has proposed a novel method for manufacturing interior parts that attempts to solve all of the above-mentioned conventional problems.

This method involves coating the surface of at least one of the male and female molds with a resin solution that changes color when exposed to light and solidifying it to form a skin layer. This method is made by injecting and foaming a foamable resin inside the L. This method can significantly reduce the number of manufacturing steps compared to the conventional method using sheet materials, and also causes problems such as wrinkles in the skin layer. It was possible to improve the yield by eliminating the problem, and it also had the advantage of being excellent in feel and texture and not discoloring even when exposed to light. However, on the other hand, the skin layer of interior parts manufactured by this method has to be relatively thin because non-yellowing urethane resin liquid tends to drip when applied and is difficult to apply thickly. Therefore, there is a problem that the strength as a skin layer is slightly inferior.

However, even if it were possible to apply a thick layer of non-yellowing urethane resin liquid to improve strength, the resin liquid is relatively expensive, which would increase the cost of the final product, which would be undesirable. It was invented in light of the background of The purpose of this invention is to provide a method for manufacturing the same.

In other words, ``This invention includes a first step of applying a non-yellowing urethane resin liquid to the surface of at least one of the male and female molds, and a step of applying a powdered thermoplastic resin on the resin liquid applied. a second step of electrostatically applying the powdered thermoplastic resin, a third step of forming a continuous film by heating and dissolving the applied thermoplastic resin in powder form, and a step of foaming the coated thermoplastic resin in the mold. This method is characterized by comprising a fourth step of injecting and foaming a synthetic resin liquid.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a process diagram showing the manufacturing method according to the present invention, and each process will be explained below with reference to the diagram.

The manufacturing method according to the present invention consists of four steps shown in FIGS. 1A to 1D. In other words, in the first step, Figure 1A
As shown in , a non-yellowing urethane resin liquid 2 colored in a desired color is applied to the surface of at least one of the male and female molds (in this figure, the mold surface of the female mold 1). The coating may be carried out by spray coating, for example, as shown in the figure, and the thickness of the coating may be 10 to 40 mm.
degree is preferred. Next, in the second step, as shown in Figure B', after the resin liquid layer 3 has been appropriately solidified or gelled, a powdered thermoplastic resin, such as a urethane resin, is electrostatically applied. do.

At this time, the thickness of the powder resin layer 5 is preferably about 40 to 300 µm, and is applied as uniformly as possible. Next, in the third step, as shown in FIG. 1C, the applied powder resin layer 5 is heat-dissociated to form a continuous film 6.

The powder fat layer 5 may be heated, for example, by introducing the female mold 1 into a suitable heating furnace 7 (for example, an electric furnace). In the fourth step, as shown in Figure ○, the male mold 8 is placed opposite the female mold 1 on which the continuous coating 6 has been formed, and the foamed birch resin liquid 9 is injected into the space created between the two. For example, a urethane-based foaming resin liquid 9 is used.Next, if the male and female molds 198 are released after being left for a predetermined period of time, the desired result is obtained as shown in Figure i. It is molded in the shape of L and has a surface layer 3a made of a non-yellowing urethane resin liquid, and a backing layer formed by dissolving and solidifying the powdered thermoplastic resin 4 below the skin layer 3a. It is possible to obtain a final product Q with a day a.Since both the skin layer 38 and the backing layer 6a are made of urethane, they have extremely high affinity. Therefore, the final product obtained by this method is The skin is extremely rutted, and has the characteristics of flexibility, excellent light resistance and low-temperature properties, and a good feel and appearance.On the other hand, in terms of ease of manufacture, conventional This method is much simpler than the method using a sheet material, and since powder coating technology is used to form the backing layer 6a, the thickness of the backing layer 6a can be easily increased. Moreover, the price of the powdered resin 4 which is to become the backing layer 6a is much cheaper than the yellowing urethane resin liquid 2 which is to become the skin layer 3a.
Compared to the case where the thickness of the skin layer 3a is increased without providing the skin layer 3a to make the skin strong, the purpose of the aircraft can be achieved at a lower cost. As is clear from the above explanation, the method of this invention applies
A first step of applying a non-denaturing urethane resin liquid, a second step of electrostatically applying a powdered thermoplastic resin onto the applied resin liquid, and a second step of electrostatically applying a powdered thermoplastic resin onto the applied This is because it consists of a third step of heating and dissolving the thermoplastic resin to form a continuous film, and a fourth step of injecting and foaming a foaming resin solution into the mold formed by forming the film. , it is possible to inexpensively produce a final product with a skin that is relatively tough and does not change color even when exposed to light.

[Brief explanation of drawings]

1A to 1E are process diagrams showing the manufacturing method according to the present invention. 1...Female mold, 2... Trout yellowing urethane resin liquid,
4... Powdered thermoplastic resin, 6... Continuous coating, 7... Heating furnace, 8... Male mold, 9... Foaming resin liquid. Figure 1

Claims (1)

[Claims] 1. A first step of applying a non-yellowing urethane resin liquid to the surface of at least one of the male and female molds, and electrostatically applying a powdered thermoplastic resin onto the resin liquid applied. a second step of heating and dissolving the applied powder thermoplastic resin to form a continuous film;
A method for manufacturing interior parts for automobiles, comprising a fourth step of injecting and foaming a foamable resin liquid into the mold formed by forming the coating.