JPH08156007A - Forming of resin molding and resin holding - Google Patents

Abstract

PURPOSE: To cause a mixing ratio to change partially in the case different types of material are mixed to form a resin molding. CONSTITUTION: A rubber material comprising a rubber ingredient containing a magnetic material and a resin material comprising polypropylene 21 as a main material are mixed, and this mixture is injected into a molding chamber 13. Then before being cured, the rubber ingredient is attracted by a magnet part 11a. Thus it is possible to change the mixing ratio of the materials easily in the cross-section structure of a resin bumper. The surface of the bumper is composed of a hard thin film layer 21 as a main material, so that it is hard and almost scrath-free, and as a whole, the bumper is of a soft resin contain ing a large amount of the rubber ingredient 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a resin molded product formed by molding a rubber material and a resin material, and a resin molded product formed by the molding method.

[0002]

2. Description of the Related Art In recent years, resin bumpers made of a resin material have been used in automobiles. Since the resin bumper is required to have impact resistance, it is molded by mixing rubber materials. On the other hand, it is known that the resin material is colored in advance and coating after molding is omitted, but in the case of a metallic color, compatibility between the aluminum powder to be mixed and the rubber material is poor,
When mixed and molded as it is, the gloss decreases.

Therefore, conventionally, as shown in FIGS. 3 and 4, the surface layer 1 is molded with a resin material mixed with aluminum powder, and the inner layer 2 is molded with a resin material mixed with a rubber material. And a resin bumper 3 having a sandwich structure was manufactured.

[0004]

The above-mentioned conventional resin bumper has the following problems. Since it has a sandwich structure, the thickness of the inner layer mixed with the rubber material is small and the impact resistance is poor. In the case of the surface layer mixed with aluminum powder, it has to be made thinner than the case of a single layer, so that a difference in the flow rate partially occurs when filling in the mold,
As shown in Fig. 5, aluminum powder 4
The orientation changes, and a so-called weld pattern occurs.

The present invention has been made in view of the above problems, and when a resin molded product is molded by mixing different materials, it is easy to partially change the mixing ratio. The purpose is to provide a method.

[0006]

In order to achieve the above object, the invention according to claim 1 is a method for molding a resin molded article which is formed by molding a rubber material and a resin material. A magnetic material is included in one of the material and the resin-based material, and the contained product and the other are mixed and filled in a mold, and the contained product is attracted in a predetermined direction by magnetic force before molding and molded. There is.

The invention according to claim 2 is based on claim 1.
In the method for molding a resin-molded article described in (1), the magnetic material is contained in the rubber-based material, and aluminum powder is mixed with the resin-based material for molding. Furthermore, in the invention according to claim 3, in a resin molded product formed by molding a rubber-based material and a resin-based material, a magnetic material is included in the rubber-based material, and the contained product and the resin-based material are Is mixed and filled in a mold, and before being cured, the contained product is attracted in a predetermined direction by magnetic force, and a thin film layer of a resin-based material having a small mixing ratio of the rubber-based material is formed on the surface of the resin-molded product. It is formed and configured.

[0008]

In the invention according to claim 1 configured as described above, the magnetic material is contained in one of the rubber-based material and the resin-based material to be mixed, and the magnetic material is mixed and filled in the mold and cured. When a magnetic force is applied before with a magnet or the like, the side containing the magnetic material is attracted to the side of the magnet, so that the attracted side is a layer having a large amount of the component and the opposite side is a layer having a small amount of the component. In the invention according to claim 2 configured as described above, since the rubber-based material contains the magnetic material, a layer containing a large amount of the rubber-based material is formed on the magnet side, and the rubber-based material is A resin layer containing a large amount of aluminum powder is formed on the side opposite to the attracted side.

Further, in the invention according to claim 3 configured as described above, the magnetic material is contained in the rubber material, the resin material is mixed with the magnetic material, and the mixture is filled in the mold before being cured. By attracting the rubber-based material with a magnetic force, a resin layer having a small mixing ratio of the rubber-based material is formed on one surface side.
That is, a thin film layer of a resin material having a low mixing ratio of the rubber material is formed on the surface of the resin molded product.

[0010]

As described above, according to the present invention, it is possible to partially change the distribution ratio of the material in the resin molded product by attracting the magnetic material contained in one of the different materials to be mixed. A molding method of a molded product can be provided.

According to the second aspect of the present invention, it is possible to form a layer containing a large amount of rubber material on one surface while containing a large amount of aluminum powder on the other surface. Further, according to the invention of claim 3, there is provided a resin molded product in which a large amount of a rubber-based material is concentrated on one surface side and a thin film layer of a resin-based material having a small mixing ratio of the rubber-based material is formed on the other surface side. be able to. According to these, it is possible to easily form a layer in which the mixing ratio of the resin material and the rubber material is different inside the resin molded product, and the layer thickness can be easily adjusted according to the mixing ratio of the original resin material and the rubber material. It can be thin or thick.

When the resin molded product is a resin bumper, a resin layer containing a small amount of a rubber material is formed on the surface layer, so that only the surface is hard and is not easily scratched. Also, if you want to maintain the overall thickness,
The thinner the surface layer is, the thicker the rubber material is and the more the impact resistance is increased. On the other hand, in order to maintain impact resistance, it is also possible to make the layers containing a large amount of rubber-based material the same in thickness and thin only the surface layer, in which case the overall thickness can be reduced.
Further, since the layers are not thinly formed as in the conventional case, it is difficult to cause a partial difference in the flow rate when filling the mold, and a weld pattern does not occur. In addition, it is easy to form a thin film layer of a rubber-based material, and it is useful in surface slipping processing and the like.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional structure of a mold used in a method for molding a resin molded product according to an embodiment of the present invention, and FIG. 2 shows a sectional structure of a resin bumper to be molded. In the figure, a mold 10 is composed of a convex core mold 11 and a concave cavity mold 12. Core type 11
Has an electromagnet portion 11a inside along the molding surface so that magnetic lines of force penetrate through the molding surface when electricity is applied from the outside. In other words, the N pole or the S pole is mounted so as to face the molding surface. In this embodiment, the electromagnet portion 11a is provided on the core die 11 side, but it may be provided on the cavity die 12 side if necessary, and further, it may be attached outside the die. You can also do it. In any case, it may be arranged so that the magnetic force lines pass through the molding surface in the direction in which the component containing the magnetic material is desired to be drawn. Of course, not only electromagnets but also heat-resistant permanent magnets can be used.

On the other hand, in the cavity mold 12, there is formed a resin injection path 12a which opens to the molding surface. The injection path 12a becomes the gate portion 12a1 at the opening and the liner portion 12a2 at the other path. There is. Molding chamber 13 formed between core mold 11 and cavity mold 12
Is the shape of the resin bumper 20 in this embodiment, holds the core mold 11 and the cavity mold 12 by an injection molding machine (not shown), fills the molten resin through the injection passage 12a, and after curing, The resin bumper 20 which is a resin molded product is taken out by opening 11 and 12. These molds 11 and 12 are basically the same as the molds for performing ordinary resin molding, and the mold shape and injection path are appropriately determined according to the molded product.

The molten resin filled through the injection passage 12a is a resin material containing polypropylene 21 mainly mixed with aluminum powder 22, and a rubber component 23 containing a magnetic material.
It is constituted by mixing with a rubber-based material consisting of. In this embodiment, the magnetic material is contained on the rubber material side which is the rubber component 23. However, the magnetic material may be contained on the resin material side as required. Also,
Polypropylene 21 is used as the resin material, but the material can be changed according to the purpose of use of the resin molded product. Furthermore, regarding resin-based materials and rubber-based materials,
The material is not necessarily limited to one type, and other types of materials may be mixed.

Next, the molding procedure of this embodiment will be described. The core mold 11 and the cavity mold 12 are set in the resin molding machine, and the molds 11 and 12 are closed to fill the molding chamber 13 with the molten resin obtained by mixing the resin material and the rubber material through the injection passage 12a. To do. Since the resin bumper 20 is formed of a single layer, the molding chamber 13 has a sufficient thickness, the molten resin is smoothly filled at the time of filling, and a large difference does not occur in the partial flow velocity. Therefore, the aluminum powder 22
There is no weld pattern in which the direction of is locally changed.

After the molten resin is filled and before being cured, the electromagnet portion 11a is energized. When the electromagnet portion 11a is energized, the rubber component 23 containing the magnetic material in the molding chamber 13 becomes
Be attracted to. That is, as shown in FIG.
In the cross section of the resin bumper 20, the rubber component 23 is attracted to the side in contact with the core mold 11, and the rubber component 23 is large in the distribution ratio of the resin. That is, a layer having a large mixing ratio of the rubber material is formed on the side in contact with the core mold 11, and a layer having a large mixing ratio of the resin material is formed on the side in contact with the cavity mold 12. At this time, in the drawing, the thickness of the layer in which the mixing ratio of the resin material is large on the side of the cavity mold 12 is exaggeratedly drawn. In reality, a thin film layer of polypropylene 21 containing almost no rubber component 23 is formed, and only the surface is hard, and the rubber component 23 as a whole makes the resin bumper 20 soft and large in impact resistance.

The compatibility between the aluminum powder 22 and the rubber component 23 is not good, but when the rubber component 23 is drawn toward the core mold 11, the aluminum powder 22 is relatively pushed toward the cavity mold 12 side and gathers on the surface. The gloss does not deteriorate.
By the way, Japanese Patent Laid-Open No. 62-198423 discloses a technique of attracting a magnetic material with an electromagnet and collecting it on one side of a resin material. The technique disclosed in the publication simply involves adding a magnetic material to a resin material, and the magnetic material is brought closer to one surface side to improve the color developability on the other surface side. That is,
This is a technology for gathering magnetic materials in a single resin layer.

On the other hand, in the present invention, there is a big difference in that different kinds of materials are further divided so that the mixing ratio of the materials is appropriate. In particular, the film thickness of one of the materials can be easily reduced to a level that cannot be obtained by ordinary resin molding, that is, from the injection molding level to the coating level. Thus, the rubber component 2 containing the magnetic material
The rubber-based material composed of 3 and a resin-based material mainly composed of polypropylene 21 are mixed and injected into the molding chamber 13, and the rubber-based material is attracted by the electromagnet portion 11a before being cured. In, it is possible to easily change the mixing ratio of the materials. Here, a hard thin film layer mainly composed of polypropylene 21 is formed on the surface, and the surface is hard and is not easily scratched.
It becomes a soft resin bumper 20 with many.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a mold used in a method for molding a resin molded product according to an embodiment of the present invention.

FIG. 2 is a sectional view of a resin bumper.

FIG. 3 is a perspective view of a conventional resin bumper.

FIG. 4 is a sectional view of a conventional resin bumper.

FIG. 5 is an explanatory diagram showing a generation state of a weld pattern in a conventional resin bumper.

[Explanation of symbols]

 10 ... Mold 11 ... Core type 11a ... Electromagnet part 12 ... Cavity type 13 ... Molding chamber 20 ... Resin bumper 21 ... Polypropylene 22 ... Aluminum powder 23 ... Rubber component

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Claims (3)

[Claims] 1. A method of molding a resin molded product formed by molding a rubber-based material and a resin-based material, wherein one of the rubber-based material and the resin-based material contains a magnetic material and A method for molding a resin molded product, characterized in that the other product is mixed and filled in a mold, and before being cured, the contained product is attracted in a predetermined direction by magnetic force. 2. The resin molding method according to claim 1, wherein the rubber material contains the magnetic material, and the resin material is mixed with aluminum powder. How to mold the product. 3. A resin molded product formed by molding a rubber-based material and a resin-based material, wherein the rubber-based material contains a magnetic material, and the product containing the magnetic material is mixed with the resin-based material. It is characterized in that it is filled in a mold, and before being hardened, the contained product is attracted in a predetermined direction by a magnetic force, and a thin film layer of a resin material having a small mixing ratio of the rubber material is formed on the surface of the resin molded product. Molded resin products.