Plastic and nonmetallic article shaping or treating: processes – With severing – removing material from preform mechanically,... – Simultaneous severing and shaping – or severing while work...
Reexamination Certificate
1995-04-24
2001-02-06
Ortiz, Angela (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With severing, removing material from preform mechanically,...
Simultaneous severing and shaping, or severing while work...
C264S266000
Reexamination Certificate
active
06183680
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a multilayer molded article which comprises a core layer of a thermoplastic resin and a skin material which is laminated on the core layer.
2. Description of the Related Art
A large number of plastic molded articles are used in many fields including the automobile and domestic electric appliance fields because of their low costs, free moldability and light weight. However, they have some drawbacks that they have poor appearance and cool feeling and they tend to be easily flawed. Then, it is highly desired to impart decoration and soft feeling to the plastic molded articles. Hitherto, many attempts have been made to provide a compound which satisfies such desires. But, it is difficult to produce a resin molded article having improved surface properties while maintaining the free moldability and strength from a single material, and at present, a multilayer molded article comprising a combination of plural materials which have different functions is generally used.
Many proceses are known for the production of a multilayer molded article. For example, Japanese Patent Kokai Publication No. 13859/1976 discloses a process comprising preforming a skin material by, for example, thermoforming, placing the preformed skin material in a mold, supplying a core resin melt and then integrating the two together. This process requires many molding steps and much apparatus. In addition, since each apparatus and each molding method has its own technical problems, much work and expense are necessary to produce a final product.
As disclosed in Japanese Patent Publication No. 19132/1975, another process molds a multilayer molded article using a single mold having a vacuum molding function and core resin supplying means. But, this process is no better than the above process.
To overcome the drawbacks of the above two processes, Japanese Patent Kokai Publication No. 63461/1978 discloses a process comprising placing an unpreformed skin material in a mold and then integrating the skin material and the core resin. Though this process is economical, tension of the skin material is controlled only in one direction and not in other directions, the skin material tends to be wrinkled, so that this process can produce only a simple shape article but not a deep draw molded article.
As proposed in Japanese Patent Publication No. 24807/1988, a multilayer molded article can be produced by clamping edges of a skin material between a female mold and a skin material-fixing frame, preforming the skin material, supplying a melt of a thermoplastic resin as a core material and then molding the resin. However, this process is not necessarily satisfactory for molding a large size article, in particular, having a complicated shape.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a process for producing a multilayer molded article, which process solves the problems of the conventional molding processes.
Another object of the present invention is to provide a process for producing a multilayer molded article having good appearance without wrinkles or breakage of the skin material.
A further object of the present invention is to provide a process for producing a multilayer molded article which process can simplify the production steps and produce the article economically.
According to the present invention, there is provided a process for producing a multilayer molded article comprising a core layer and a skin material laminated thereon, which process comprises the steps of:
providing a skin material between a pair of upper and lower molds,
supplying a thermoplastic resin melt between said skin material and one of said molds,
closing the molds to press and form said resin melt while holding edges of said skin material with pins provided on a skin material-fixing frame which moves along an outer peripheral wall of one of said upper and lower molds, and
cooling said molds and removing said multilayer molded article from the molds.
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Hara Takahisa
Mathubara Sigeyoshi
Matsumoto Masahito
Usui Nobuhiro
Birch & Stewart Kolasch & Birch, LLP
Ortiz Angela
Sumitomo Chemical Company Limited
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