Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reexamination Certificate
1996-11-07
2001-01-30
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C264S328800, C293S120000
Reexamination Certificate
active
06180042
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a molded article of a synthetic resin and particularly, to a process for producing a molded article of a synthetic resin, including a first construction portion having a sandwich structure including a core and an outer layer covering the core, and a second construction portion connected to the first construction portion and having a single-layer structure.
2. Description of the Related Art
For example, a bumper for an automobile vehicle is conventionally known as such a synthetic resin molded article having a sandwich structure as described above (for example, see Japanese Patent Application Laid-open No. 4-267114).
In this known bumper, a pulverized material derived from a recovered bumper of a synthetic resin is used as a core forming material for the bumper. This is effective for enabling the recovered bumper to be reutilized, thereby providing a reduction in industrial waste, a resources saving and a preservation of environment.
To promote the reutilization of the recovered bumper, it is required to increase the amount of core forming material derived from the recovered bumper, which is used in a bumper to be produced.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a process for producing a synthetic resin molded article of the above-described type, which is capable of meeting the above requirement.
To achieve the above object, according to the present invention, there is provided a process for producing a molded article of a synthetic resin including a first construction portion having a sandwich structure comprised of a core and an outer layer covering the core, and a second construction portion integrally formed with the first construction portion and having a single-layer structure, the process comprising: a first step of injecting an outer layer forming material into a molding cavity through a gate in a metal mold; a second step of injecting a core forming material to allow the core forming material to flow into the outer layer forming material existing in the gate and the cavity and to allow the outer layer and core forming materials to flow into the cavity, thereby advancing the formation of the first construction portion; a third step of allowing a front portion of the core forming material in a flowing direction to break through a front portion of the outer layer forming material in the flowing direction and allowing the core forming material to flow into the cavity, thereby advancing the formation of the second construction portion under advancement of the formation of the first construction portion; and a fourth step of pushing the outer layer and core forming materials of a double structure existing within the gate into the cavity by the outer layer material, thereby completing the formation of the first and second construction portion.
With this method, the amount of use of the core forming material derived from the recovered bumper can be increased by selecting the bumper as the synthetic resin molded article and a non-conspicuous bumper lower edge as the second construction portion. In addition, it is possible to mass-produce such a synthetic resin molded article of a high quality including first and second construction portions.
The synthetic resin molded article is not limited to the bumper and may be a cowl top garnish, wherein the second construction portion thereof is a portion located below a bonnet. In this case, the outer layer of the first construction portion is conspicuous and requires a weather resistance. Therefore, PP (polypropylene) containing a weather resistant stabilizer is used as the outer layer forming material. Only PP is used as the core forming material.
The above and other objects, features and advantages of the invention will become apparent from the following description of a preferred embodiment taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4174413 (1979-11-01), Yasuike et al.
patent: 5059361 (1991-10-01), Da Re′
patent: 5374178 (1994-12-01), Nakayama
patent: 5433910 (1995-07-01), Mukai et al.
patent: 5645786 (1997-07-01), Okada et al.
patent: 37 11 079 (1988-10-01), None
patent: 2087299A (1982-05-01), None
patent: 63-000055 (1988-01-01), None
patent: 4-267114 (1992-09-01), None
patent: 321621 (1997-12-01), None
Makuta Minoru
Ohgane Hitoshi
Takeuchi Atsushi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
McDowell Suzanne E.
Silbaugh Jan H.
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