JP2001293745A - Resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molded article high in strength, reduced in weight and having the degree of freedom of a shape by the insert molding of a light and strong strand material. SOLUTION: The resin molded article is formed by inserting the strand material 1, which is obtained by solidifying a bundle comprising a large number of continuous fibers having strength higher than that of a molding resin 2 being a matrix by a resinous binder, in the part requiring necessary strength of the resin and molding the whole. As a fiber constituting the strand material, a glass fiber, a carbon fiber, a metal fiber or the like is used. The strand material is preferably positioned at the terminal part of a rib because it is not moved during molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product obtained by insert-molding a strand material in which fibers are bundled at a site requiring strength, and more particularly to, for example, a front end carrier and an instrument panel of an automobile. The present invention relates to a high-strength and lightweight resin molded product that can be used.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining a high-strength resin molded product, there has been a method of insert-molding an iron plate.
However, this method has a drawback that the weight of the insert is extremely heavy because the insert is an iron plate. Further, since the insert product is an iron plate, there are restrictions on the insert portion, shape, and the like, which is not practical. Even if an attempt is made to use a lightweight metal material to reduce the weight, it becomes very expensive, and there has been a problem that it cannot be adopted from the viewpoint of economy.

[0003] Further, conventionally, a resin front end carrier of an automobile is made of GMT (Glass Mat Thermopl).
astic). This involves cutting a mat-shaped material, in which long fibers of glass are impregnated with a thermoplastic resin, into a predetermined size, applying heat to make it into a molten state, setting it in a molding die, and pressing it to produce a product by compression molding. Is what you do. In this case, the strength of the product can be increased by adding a large amount of glass, but the material cost is increased, and the process is complicated and the cost is increased. Furthermore, since it is formed by pressing, there is a problem that a shape that can be formed is limited and a complicated molded product cannot be produced.

In order to impart a new function to the front end carrier, it is necessary to form a complicated shape, and it is difficult to produce the front end carrier by compression molding. Therefore, injection molding with a long fiber glass-containing resin material has been receiving attention for the purpose of high strength, light weight, and low cost. However, even in this injection molding, even if a long fiber is contained in the resin and fed, the fiber is broken or cut in a screw cylinder or the like in the middle thereof, and eventually, a molded article containing the long fiber in the resin is obtained. Therefore, a molded article having high impact strength cannot be obtained. Thus, there is a limit in strength only by injection molding of a long fiber glass-containing resin material.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-strength, light-weight and low-cost device by partially reinforcing a portion requiring strength. Another object of the present invention is to provide a resin molded product using an insert having a degree of freedom in shape.

[0006]

According to the present invention, there is provided, as a means for solving the above-mentioned problems, a resin molded product described in each of the claims. In the resin molded product according to the first aspect, a high-strength, lightweight resin molded product can be obtained by insert-molding a strand material in which a number of continuous fibers having a higher elongation strength than the base material are bundled and fixed. .
In addition, since it is insert molding, it is possible to mold a complicated shape. In the resin molded product according to the second aspect, since the strand material fixes the bundle of fibers with the resin binder, the base material and the resin binder fixing the strand material melt during the molding of the resin molded product. , Resulting in an integrated structure. As a result, a molded article having higher strength can be obtained. The resin molded product according to the third aspect specifies the material of the fiber constituting the strand material, and has substantially the same operation and effect as the resin molded product according to the first or second aspect.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resin molded product according to an embodiment of the present invention will be described with reference to the drawings. 1 (a), 1 (b) and 1 (c) show a resin molded product according to an embodiment of the present invention, wherein 1 is a strand material, 2 is a molding resin as a base material, and the strength is reinforced. The strand material 1 is insert-molded in each of the parts to be formed to obtain a resin molded product. In this case, the strand material 1 is inserted into a molding die, and a resin is injected and injected into the molding die.
To be integrated. The strand material 1 is conveniently located at the end of the rib without moving during molding. In FIG. 1 (a), the strand material 1 is located at the end of the central rib, and FIG. In FIG. 1, they are arranged at three places at each end of the T-shaped section, and in FIG. 1C, they are arranged at the central protruding part. Note that the strand material 1 does not necessarily need to be located at the end, and may be arranged at a predetermined location inside the end. However, in this case, the strand material 1 is not moved during molding. Need to be retained.
In addition, the strand material 1 can be softened, bent, or the like so that the strand material 1 can be laid at a desired place, so that a desired place can be reinforced even with a complicated shape.

The strand material 1 is formed by bundling a large number of continuous fibers and hardening them with a resin binder. As the fibrous material, glass fiber, carbon fiber, metal fiber, or the like is used, and a material having higher elongation strength than the molding resin as the base material is preferable. As the resin binder, for example, a resin material having a lower melting point than the molding resin as a base material, such as a polypropylene resin, is preferable. In this case, in the insert molding, the resin binder is melted by the heat of the molding resin to form a strand. The material 1 and the molding resin 2 are bonded and integrated.

FIG. 2 (a) is a graph comparing the flexural modulus of the resin molded product when the strand material 1 is not used and when it is used, and FIG. 2 (b) is a graph comparing the flexural strengths thereof. It is. Test piece shape is 210mm × 2
A test piece measuring 0 mm × 3 mm and measuring bending elastic modulus and bending strength is a strand material having a diameter of about 2 mm obtained by bundling about 2000 continuous glass fibers having a diameter of 13 μm and hardening with a polypropylene resin as shown in FIG. As shown in FIG. 4 (b), two inserts were inserted on the left and right sides and molded from a polypropylene material. The comparison of the effect of this strand material is 8
The test was performed at a temperature of 0 ° C. From these graphs, it can be seen that the resin molded product with the strand material improved by about 1.3 times in the bending elastic modulus and about 1.5 times in the bending strength as compared with the case without the strand material. You can see what was measured. As described above, in the resin molded product obtained by insert-molding the strand material 1, the strength is remarkably improved, and the weight can be reduced because a heavy material is not used.

FIG. 3 shows a case where the strand material 1 is used as a resin carrier for a front end of an automobile, and the strand material 1 is insert-molded in a portion for reinforcing the strength, and this portion is indicated by oblique lines. The resin molded product of the present invention can be applied not only to the front end carrier of the automobile but also to various large resin molded products such as instrument panels and cockpits, as well as to various resin molded products requiring strength. It is possible.

[Brief description of the drawings]

1 (a), 1 (b) and 1 (c) are perspective views showing the positions of inserts of a strand material in three cases of a resin molded product containing a strand material according to an embodiment of the present invention.

FIG. 2 is a graph comparing the strength of a resin molded product without a strand material and the strength of a resin molded product with a strand material of the present invention, wherein (a) is the flexural modulus and (b) is the flexural strength. It is a comparative graph.

FIG. 3 is a perspective view of an example in which the present invention is applied to a resin carrier of a front end of an automobile.

4A and 4B are diagrams illustrating (a) a test piece and (b) a strand material used for testing the graph of the measurement results shown in FIG. 2;

[Explanation of symbols]

 1: Strand material 2: Molding resin

Claims (3)

[Claims] 1. A resin molded product obtained by inserting a strand material in which a large number of continuous fibers having a strength higher than that of a base material are bundled and fixed and inserting the strand material into a portion requiring strength, and performing resin molding. 2. The resin molded article according to claim 1, wherein the strand material is formed by solidifying a bundle of a large number of fibers with a resin binder. 3. The resin molded article according to claim 1, wherein the fiber is made of glass, carbon, or metal.