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
1995-02-09
2001-03-20
Ortiz, Angela (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
C264S328700
Reexamination Certificate
active
06203744
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing a molded article of a thermoplastic resin. In particular, the present invention relates to a method for effectively producing a molded article which consists of a thermoplastic resin or comprises a thermoplastic resin core and a skin material layer thereon without the deterioration of appearance.
2. Description of the Related Art
In the production of a molded article of a thermoplastic resin, various improvements have been proposed to improve quality of the molded articles and increase production efficiency. For example, Japanese Patent Kokai Publication No. 101322/1984 discloses supply of a resin melt through a resin conduit formed in a wall of a mold attached to a lower platen, namely a lower mold. Japanese Patent Kokai Publication No. 31929/1985 discloses supply of a resin melt through a resin conduit formed in a wall of a lower mold and closing the mold at a specific timing. However, both methods cannot completely prevent uneven gloss or small wrinkles which are so-called cold marks around the resin conduit having an opening on an inner wall of the mold. To suppress the formation of the cold marks, it may be contemplated to increase a resin temperature and/or a mold temperature. However, a time period from the finish of molding to the removal of the molded article from the mold becomes longer, so that a molding cycle is prolonged and in turn the productivity is worsened.
A multilayer molded article having a skin layer on the thermoplastic resin molded article to improve ornamental properties and functions of the article is widely used in various fields such as automobile interior panels or electric appliances. One of the methods for producing such multilayer molded article is disclosed in Japanese Patent Kokai Publication No. 235613/1989. In the conventional methods for producing the multilayer molded article including this method, since a high temperature resin melt is continuously supplied from a position close to the skin material, a part of the skin material is subjected to the high temperature for a longer time than other parts and then deteriorated and deformed so that various defects such as crush, unevenness or breakage of the skin material appear.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a method for producing a molded article of a thermoplastic resin having no or little cold marks.
Another object of the present invention is to provide a method for producing a multilayer molded article comprising a thermoplastic resin core and a skin material without damaging the skin material.
According to a first aspect of the present invention, there is provided a method for producing a molded article of a thermoplastic resin, comprising providing upper and lower molds having a product part-molding section and a non-product part-molding section, supplying a melt of a thermoplastic resin in a cavity of said molds through a resin melt passage which is formed in a wall of one of said molds and has an opening for supplying said melt in said non-product part-molding section when a clearance of said cavity is larger than a thickness of a finally produced article, closing the molds to effect press molding, cooling the molds.
According to a second aspect of the present invention, there is provided a method for producing a multilayer molded article comprising a resin core and a skin material provided on said resin body, which method comprises providing upper and lower molds having a product part-molding section and a non-product part-molding section, placing a skin material between said upper and lower molds, supplying a resin melt in a space defined by said skin material and one of said upper and lower molds through a resin melt passage which is formed in a wall of said one mold and has an opening for supplying said melt in said non-product part-molding section when a clearance of said cavity is larger than a thickness of a finally produced article, closing the molds to effect press molding, and cooling the molds.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 2666230 (1954-01-01), Sherman
patent: 4076788 (1978-02-01), Ditto
patent: 4091057 (1978-05-01), Weber
patent: 4184835 (1980-01-01), Talbot
patent: 0107431 (1984-05-01), None
patent: 0333198 (1989-09-01), None
patent: 333198 (1989-09-01), None
patent: 2329434 (1977-05-01), None
patent: 2154499 (1985-09-01), None
patent: 59-101322 (1984-06-01), None
patent: 60-031929 (1985-02-01), None
patent: 1-235613 (1989-09-01), None
patent: 3-236917 (1991-10-01), None
Hara Takahisa
Hieda Kazuo
Matsumoto Masahito
Matubara Shigeyoshi
Usui Nobuhiro
Birch & Stewart Kolasch & Birch, LLP
Ortiz Angela
Sumitomo Chemical Company Limited
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