JPS58171925A - Foamed resin molded body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molded article made by heating and foaming resin beads such as expandable polypropylene in a mold.

Resin beads containing a foaming agent are filled into a mold, the foaming agent is decomposed by heating it, the beads are expanded by the generation of organic gas or N2 gas, etc., and each expanded bead is Foamed resin molded articles, which are formed by bringing them into close contact at their interfaces to form a single shape, are lightweight and have excellent heat insulation, heat retention, and impact resistance, so they are used in various materials.

The characteristics of such foamed resin molded products are mainly determined by the material resin, but using the same resin, to improve strength, it is necessary to lower the foaming ratio, and conversely, to increase volume and reduce weight, it is necessary to use foaming. Just increase the magnification.

However, the upper limit of the expansion ratio is usually about 45 times, and there is inevitably a limit. Therefore, even if the material only needs to be bulky, it is necessary to use more foamable resin beads than necessary.

In view of the above-mentioned conventional problems, the present inventors have created the present invention to effectively solve the problems. To provide a foamed resin molded article having a volume of .

In order to achieve such an object, the present invention provides a structure in which the foamed resin beads constituting the foamed resin molded article have a
The gist is that it encloses bulking substances such as paper powder or inorganic fillers.

An example of the implementation of the present invention will be described in detail below based on the accompanying drawings.

FIG. 1 shows a mold for producing the entire molded article of the present invention, and the mold 1 consists of upper and lower hollow molds 2.3.
3 is divided into two hollow parts 4a and 4b by partition plates 2a and 3a, and a steam inlet vibe 5 is attached to the hollow part 4a, and a steam outlet vibe 6 is attached to the hollow part 4b, respectively. . Then, a molding cavity 7 is formed between the lower surface of the upper mold 2 and the upper surface of the lower mold 3, and the cavity 7 and the hollow parts 4a, 4b are communicated with each other through holes 8..., and superheated steam is sent into the hollow part 4a. Steam enters the cavity 7 through the hole 8, and steam that has entered the cavity 7 exits through the hole 8 into the hollow portion 4b. And upper mold 2
is equipped with a pipe 9.9 for injection of foamed resin beads that faces Capity 7.

In the above, for example, polypropylene beads 10 containing a foaming agent and paper powder 11 as a bulking material are described.
were mixed at a weight ratio of 60:40 and filled into the cavity 7 from the injection pipe 9, and as shown in FIG. 2, paper powder 11.
... should intervene.

Next, the valve of the steam inlet vibe 5 is opened, and the mold 2.3
Superheated steam of about 120C is introduced into the hollow part 4a of the hole 8.
This superheated steam is sent into the cavity 7 via... and heated for about 3 minutes. Then, the foaming agent within the beads 10 decomposes and generates N2 gas, etc., and the beads 10 expand accordingly.

As a result, as shown in FIG. 3, the foamed polypropylene beads 10a come into close contact with each other with their boundary surfaces 12, and the paper powder 11 is enveloped by this boundary surface 12. Therefore, the volume of the foamed molded product increases by the amount of the paper powder 11.

Also, at this time, the paper powder 11... is the foamed beads 10a.
Beads 10a are embedded between...
The bonding strength of ... is also improved.

In the above embodiments, the foamable resin beads are made of polypropylene, but the present invention is not limited to this, and various resins such as polystyrene or polyethylene can be used.

However, considering that polypropylene has superior heat resistance, oil resistance, chemical resistance, and impact resistance compared to other resins, as well as low heat shrinkage and good dimensional stability, foamed polypropylene beads are preferred. can be said to be optimal. Furthermore, the substance to be mixed into the beads as a bulking substance is not limited to paper powder, but may also be an inorganic filler or the like, as long as it is available at a low cost. In addition, when it is necessary to maintain strength while increasing volume, it is possible to mix paper powder or other material coated with an adhesive onto the surface of the beads, so that when foamed, the bulking material also acts as a binder. Just do it.

As is clear from the above description, according to the present invention, a bulking material such as paper powder is heated together with foamable resin beads in a mold, and the paper powder is wrapped in the mutually close boundary surfaces of the foamed beads. Therefore, the volume can be increased without significantly increasing the expansion ratio, and its production can be done by simply mixing inexpensive paper powder etc. with the foamable beads.
It has many advantages such as not requiring any special pressurizing means.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a mold for producing a foamed resin molded article according to the present invention, and FIG. 2 is a diagram showing the state inside the cavity before foaming. , FIG. 3 is a diagram of the structure of the molded product after foaming. In the drawing, 10 is a resin bead, 10a is a foamed resin bead, 11 is a filler material, and 12 is a boundary surface. Patent applicant: Honda Motor Co., Ltd. Agent: Tokyo Seat Co., Ltd. Patent attorney: Yoichi Shimoda Patent attorney: Kunihiko Ohashi

Claims (1)

[Claims] A foamed resin molded article characterized in that a bulking substance is wrapped between the mutually intimate interfaces of foamed resin beads.