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
Patent
1998-04-29
2000-02-29
Silbaugh, Jan H.
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
2643288, 26432813, 425130, 293120, B28B 722
Patent
active
060305673
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an improvement in a process for producing a sandwich-shaped synthetic resin-molded article, and in particular, to a process for producing a sandwich-shaped synthetic resin-molded article comprised of a core and an outer layer which covers the core, comprising a first step of injecting an outer layer forming material into a forming cavity in a mold through a gate, a second step of injecting a core forming material to flow into the outer layer forming material present within the gate and the cavity and to allow the outer layer and core forming materials to flow within the cavity, and a third step of pushing the core and outer layer forming materials having a double structure existing within the gate into the cavity by the outer layer forming material, thereby molding the core and the outer layer.
BACKGROUND ART
There is such a conventionally known producing process disclosed in Japanese Patent Application Laid-open No.6-328509. In this case, the maximum value of an injection speed V.sub.2 of the core forming material at the second step is set to be lower than the maximum value of an injection speed V.sub.1 of the outer layer forming material at the first step.
In a producing process of such type, while the outer layer forming material is flowing within the cavity, the core forming material is allowed to flow into the outer layer forming material. However, after a front portion of the outer layer forming material in a flowing direction reaches a terminal end of the cavity to stop its flowing, it is difficult to allow the core forming material to flow into the front portion of the outer layer forming material in the flowing direction.
If the injection speed is set as in the prior art under such a circumstance, the following problem is liable to arise: The front portion of the core forming material in the flowing direction has not yet flown into the front portion of the outer layer forming material in the flowing direction at a time point when the front portion of the outer layer forming material in the flowing direction reaches near the terminal end of the cavity. Due to this, it is impossible to allow the core forming material to flow into the front portion of the outer layer forming material in the flowing direction and hence, it is impossible to produce a synthetic resin-molded article having a sandwich structure over the whole thereof.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a producing process of the above-described type, wherein the core forming material can be reliably allowed to flow into the front portion of the outer layer forming material in the flowing direction, thereby producing a synthetic resin-molded article having a sandwich structure over the whole thereof.
To achieve the above object, according to the present invention, there is provided a process for producing a sandwich-shaped synthetic resin-molded article comprised of a core and an outer layer which covers the core, the process comprising a first step of injecting an outer layer forming material into a forming cavity in a mold through a gate at an injecting speed V.sub.1, a second step of injecting a core forming material at an injection speed V.sub.2 higher than the injection speed V.sub.1, while injecting the outer layer forming material at the injection speed V.sub.1, in order to allow the core forming material to flow into the outer layer forming material present within the gate and the cavity and to allow the outer layer and core forming materials to flow within the cavity, the injection speed of the outer layer forming material being then reduced to be lower than the injection speed V.sub.1, while the injection speed V.sub.2 is maintained, and a third step of injecting the outer layer forming material at an injection speed V.sub.3 equal to or lower than a final injection speed of the outer layer forming material at the second step, and pushing the core and outer layer forming materials having a double structure and existing withi
REFERENCES:
patent: 4120922 (1978-10-01), Lemelson
patent: 4174413 (1979-11-01), Yasuike et al.
patent: 4366110 (1982-12-01), Morita et al.
patent: 4550043 (1985-10-01), Beck
patent: 5059361 (1991-10-01), Da Re
patent: 5178805 (1993-01-01), Yokota
patent: 5423673 (1995-06-01), Sawae et al.
Honda Giken Kogyo Kabushiki Kaisha
Mason Suzanne E.
Silbaugh Jan H.
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