JPS5847974B2 - Simultaneously molded products using different raw materials - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a simultaneous molding product made of different raw materials, which is made by using different raw materials made of two or more types of expandable thermoplastic resin particles and integrally fused and molded without mixing the respective raw materials. trying to get something.

In conventional foam molded products, when some parts require strength or some parts require chemical resistance,
Products manufactured by separately molding foamed molded products using raw materials made of two or more types of expandable thermoplastic resin particles of different materials, and then forming a single foamed molded product by means such as fitting or adhesion. However, there are various problems such as poor integrity due to adhesives coming off, and the fact that each molded item must be assembled by adhesives etc. during manufacturing, which is time consuming. Improvements were also requested.

Therefore, in this invention, it is possible to solve the above-mentioned conventional problems, and its structure is made of a raw material made of two or more types of expandable thermoplastic resin particles of different materials. Different types of raw materials are molded simultaneously without mixing, and their boundary parts are fused together, and the bubbles are almost regular at the boundary where the hard foam molded part goes to the softer foam molded part. It is characterized by being molded so that it has a parallel orientation.

Next, embodiments of the present invention will be illustrated below with reference to the drawings.

A shows the entire foam molded product, and 1 and 2 are foam molded parts made of raw materials made of expandable thermoplastic resin particles of different materials, and both parts 1 and 2 are made of a mixture of different raw materials. They are molded at the same time without any overlapping, and their boundary portions 3 are fused together.

In particular, among the foam molded parts 1 and 2 made of different materials, the hard foam molded part is formed with good orientation in which the air bubbles at the boundary part 3 toward the softer foam molded part are arranged in parallel in a substantially regular manner. will be done.

For example, if part 1 is made of foamed polystyrene resin and part 2 is made of foamed polyolefin resin (for example, foamed polyethylene resin), the foamed part 1 side, which is the hard side after foam molding, This provides good alignment at the boundary.

If the above-mentioned dissimilar raw materials are reversed at the portions 1 and 2, the orientation at the boundary portion on the side of the portion 2 will be improved, although not shown.

In each of these examples, expanded polystyrene resin is inexpensive but has no oil resistance, so both are molded simultaneously so that expanded polyolefin resin is formed in areas that require oil resistance, and the boundaries between them are The portions 3 are fused together, and at the boundary portion, the air bubbles at the boundary where the hard foam molded portion 1 side goes to the softer foam molded portion 2 side are arranged approximately regularly in parallel to improve orientation. As a result, even if the above-mentioned dissimilar raw materials are made of different materials, which are known to have problems in mutual retention, their mutual retention is further strengthened, making them suitable for use as packaging materials for machine parts, for example, and other uses. used.

Regarding different materials, as mentioned above, this is a simultaneous molded product made of different materials with different materials, but after foam molding, the hard foam molded part and the softer foam molded part are not compatible with each other. The method differs depending on the material and expansion ratio (expansion ratio of the particles after pre-foaming), etc., and can be carried out by combining various materials and expansion ratios.

In the case of Fig. 1 (Fig. 2), the molding method for obtaining a simultaneous molded product using different materials having the above-mentioned configuration is to The parts are divided into candy-like shapes using a large number of pins or comb-like objects, or partitioned from the beginning by partition members forming cylinders, and different types of raw materials are filled into the partitioned mold cavities, and after filling, the parts are heated during heating. When the partition member is retreated from the mold cavity, the air bubbles in the hard foamed part enter the softer foamed part, and the air bubbles are arranged almost regularly in parallel, forming a foamed part made of different raw materials. In addition to the above-mentioned molding method, a predetermined area of the mold cavity is partitioned off with a partition member like the one described above that can be freely entered and exited, and the mold cavity other than the predetermined area that has been partitioned is first The raw material on the side that will become the hard foam molded part 1 is partitioned, and while the raw material is heated and expanded and the fusion is completed, the partitioning force, which is the predetermined area described above, is applied to the side that will become the soft foam molded part 2. When the raw material is filled and the partition member is removed after filling, the raw material that will become the soft foamed part has not yet been heated, but the raw material that will become the hard foamed part has already been heated. As thermal expansion is progressing, the bubbles on the hard side of the boundary part enter into the soft side, and the bubbles are arranged in parallel almost regularly, and the raw material on the soft foam molding part side is transferred to the η mouth. By heating, foam molded parts made of different raw materials can be fused together and shaped.

In the above case, the hard foam molded part 1 is foamed polystyrene and the soft foam molded part 2 is foamed polyolefin such as foamed polyethylene, so the foam molded part 2 can partially impart oil resistance to the molded product. Become.

Depending on the application, it is also possible to use raw materials opposite to those described above.

Of course, it is also possible to combine other raw materials with different materials depending on the purpose.

In addition, in the above-mentioned simultaneous molded product made of different raw materials according to the present invention, in addition to having a border at approximately the center of the molded product as shown in FIG. 1 (FIG. 2), a corner part and a fourth As shown in the figure, the boundary portion may be determined as appropriate depending on the use and type of the foamed article, such as the portion into which the legs of the packaged object B are inserted.

As described above, according to the present invention, two or more types of raw materials of different materials are made of expandable thermoplastic resin particles, and the different types of raw materials are molded at the same time without being mixed with each other, so that the boundary between them is They are fused together, and the bubbles at the boundary between the hard foam molded part and the softer foam molded part become almost regular, resulting in good bubble orientation. Even with dissimilar raw materials that are known to have problems in their ability to retain each other, their ability to retain each other is further strengthened, their integrity is enhanced, and the strength is far greater than that of conventional combination products.

Therefore, the wall thickness can be reduced accordingly.

As for molded products, the boundaries between different types of raw materials are clear, and there are a wide variety of molded products that are adapted to the functions required depending on their use, such as those that require partial reinforcement, those that require chemical resistance, and other partially This means that products with added value can be easily provided.

Furthermore, the above-mentioned device according to the present invention can save the labor of separately molding and assembling the components during manufacture, and thus can contribute to cost reduction.

[Brief explanation of drawings]

The figures illustrate an embodiment of the present invention, and FIG. 1 is a collapsed view, FIG. 2 is an enlarged flat view of the main part, and FIGS. 3 and 4 are cross-sectional views with modified boundary parts. be. A... Entire foam molded product, 1, 2...
Foam molded parts of foam molded products using different raw materials, 3...
...Boundary part.

Claims (1)

[Claims] 1 Consisting of raw materials made of two or more types of expandable thermoplastic resin particles having different materials, the different types of raw materials are simultaneously molded without mixing, and their boundary parts are fused together, and The boundary part is made of different materials, characterized in that the hard foamed part is molded so that the bubbles at the boundary towards the softer foamed part are oriented in a substantially regular arrangement. Simultaneously molded product.