JPH11314240A - Apparatus and method for producing resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent generation of a flow pattern in a molded product wherein an embossed mark part is formed on a plate-shaped main body part made of a resin having a fine metal powder mixed therewith. SOLUTION: An injection-molded product wherein an embossed mark part 4 is formed to a plate-shaped main body part 3 made of a resin having a fine metal powder mixed therewith is produced. An injection mold 1 has a film gate 5. The length of the embossed mark part 4 is set to L and the width of the film gate 5 is set to G so that G>L/10 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus and a method for manufacturing a resin molded product.

[0002]

2. Description of the Related Art Molding a resin molded product by injection molding has been actively performed. Of these types of resin molded products, those used as covers for other articles are generally constituted by a plate-shaped main body. In addition, a logo mark, that is, an embossed mark portion is integrally formed on such a main body portion for the purpose of decoration.

In order to further enhance the decorativeness of the resin molded product in which the raised mark portion is formed, a fine metal powder or the like is mixed into the resin to form the surface of the molded product. Is known to have a metallic finish.

[0004]

However, when a resin molded product in which the embossed mark is integrally formed on the plate-shaped main body is molded by injection molding, the flow direction of the resin during the injection molding is increased. A flow pattern generally called a flow mark or a weld line often occurs on the surface of the main body on the downstream side of the embossed mark along the line. When such a flow pattern occurs, the appearance of the product surface is significantly impaired. This flow pattern is, in particular, by mixing fine metal powder and the like in the resin as described above,
It is known that such a phenomenon occurs remarkably when the fluidity of the resin during injection molding is reduced.

Accordingly, the present invention is to provide a molded article having a resin plate-shaped main body in which fine metal powder is mixed and having an embossed mark formed thereon, so that generation of a flowing pattern can be effectively prevented. With the goal.

[0006]

According to the present invention, there is provided an apparatus for manufacturing an injection-molded article in which an embossed mark is formed on a resin-made plate-shaped main body in which fine metal powder is mixed. An apparatus for performing an injection molding includes a film gate in a mold for injection molding, wherein the length of the raised mark portion is L, and the width of the film gate is G, and G> L / 10. is there.

In addition, the method of the present invention is used for manufacturing an injection-molded article in which a raised mark portion having a length L is formed in a resin-made plate-shaped main body into which fine metal powder is mixed. A film gate having a width G and G> L /
A film gate 10 is formed, and a resin is injected from the film gate into a mold.

That is, according to the present invention, when manufacturing an injection-molded product in which a raised mark portion is formed in a resin-made plate-shaped main body portion mixed with fine metal powder, a mold having a film gate is used. When the length of the embossed mark portion is L and the width of the film gate is G, G> L / 10, so that the main body portion on the downstream side of the embossed mark along the flow direction of the resin during injection molding. This is based on the finding that the flow pattern is less likely to be generated on the surface of the.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a state in which a resin molded product 2 is molded inside a molding die 1.

The resin molded article 2 is formed by integrally forming an embossed mark portion 4 on a plate-shaped main body portion 3, and the surface of the resin molded product 2 is mixed with fine metal powder into resin as a molding material. It is finished in metallic tone. As a resin that can be finished in such a metallic tone, for example, a reinforced polyamide resin in which a layered silicate is uniformly dispersed at a molecular level in a polyamide resin is exemplified. As the layered silicate, for example, it is preferable to use a swellable fluoromica mineral.

The molding die 1 has a film gate 5 for injecting resin into the die. Then, when the resin is injected from the film gate 5 without taking any countermeasure at the time of molding, as shown in FIG. 1, on the downstream side of the raised mark portion 4 along the flow direction of the resin at the time of injection. There is a high possibility that the flow pattern 6 is noticeably generated on the surface of the main body 3.

However, according to the present invention, when the size of the plate-shaped main body 3 in the resin molded product 2 is about 500 × 600 mm, the length of the raised mark 4 is L, and the width of the film gate 5 is If G> L / 10, the occurrence of the flow pattern 6 can be significantly reduced.
The reason is not clear, and the present invention has been made based on findings supported by experiments.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG.
A box-shaped resin molded product having a m-shaped plate-shaped main body 3 was molded.

The resin used is a nanocomposite nylon 6 in which a swellable fluoromica mineral, which is a layered silicate, is uniformly dispersed at the molecular level as a reinforcing agent in a nylon 6 resin.
(M2350, manufactured by Unitika Ltd.) 100 parts by weight of aluminum powder having an average particle diameter of 50 μm and a thickness of 0.02 μm, that is, an aspect ratio of 2500 (manufactured by Sumitomo Color Co., Ltd., E
PC-8E-340) in an amount of 1 part by weight.

Using this resin, that is, a reinforced polyamide resin, a resin temperature of 250 ° C., a mold temperature of 80 ° C., and an injection pressure of 10 ° C.
Under a condition of 0 MPa, a film gate 5 having a predetermined thickness
The molded article 2 was injection-molded while changing the width G of the molded article 2 in various ways.

In the first example, the raised mark portion 4
Length L is 300 mm, and width G of film gate 5 is
10 mm, 30 mm, 50 mm, 100 mm, 450
mm. Then, when the condition of G> L / 10 was not satisfied and the gate widths G were 10 mm and 30 mm, a noticeable flow pattern 6 occurred. However, G>
The gate width G satisfying the condition of L / 10 is 50 mm.
In the above case, no noticeable flow pattern occurred.

In the second example, the raised mark 4
Was 50 mm in length L. And film gate 5
Is 10 mm, 30 m, as in the case of the first example.
m, 50 mm, 100 mm, and 450 mm.
In this case, for all gate widths G, G> L / 1
The condition of 0 was satisfied, and no noticeable flow pattern occurred.

[0018]

As described above, according to the present invention, when manufacturing an injection-molded article in which a raised mark portion having a length L is formed on a resin-made plate-shaped main body portion mixed with fine metal powder, A film gate having a width of G and G> L / 10 is formed in a mold for injection molding, and the resin is injected from the film gate into the mold. The generation of a flow pattern on the surface of the main body on the downstream side of the embossed mark along the flow direction can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a method for manufacturing a resin molded product according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molding die 2 Resin molded product 3 Main part 4 Embossed mark part 5 Film gate

Claims (2)

[Claims] 1. An apparatus for manufacturing an injection-molded product having an embossed mark formed on a resin-made plate-shaped main body into which fine metal powder is mixed, wherein a film is formed in an injection-molding mold. A gate having a length L,
An apparatus for manufacturing a resin molded product, wherein G> L / 10, where G is the width of the film gate. 2. A method for manufacturing an injection-molded article in which a raised mark portion having a length L is formed in a resin-made plate-shaped main body portion into which fine metal powder is mixed, the method comprising: A method for producing a resin molded product, comprising: forming a film gate having a width G and satisfying G> L / 10 in a mold, and injecting a resin from the film gate into the mold.