Injection molded articles with improved surface characteristics, production of same and apparatus therefor
AssigneeAsahi-Dow Limited
InventorsAkihiro Wada, Kichiya Tazaki, Tamotsu Tahara, Hiroshi Suzuki, Yukihisa Mizutani
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Abstract
In injection molding thermoplastic resin compositions containing reinforcing materials and/or fillers, high quality molded articles superior in surface gloss and exhibiting substantially no surface defect can be obtained, by employing a technical measure, in which only superficial layer of the inner wall surface of the mold is selectively heated, by high-frequency induction heating, to a temperature above the heat distortion temperature of the thermoplastic resin composition employed prior to injection molding and cooling and solidifying the resin.
Claims3
A method of injection molding thermoplastic resins or thermoplastic resins containing reinforcing material and/or fillers comprising:
- heating selective inner surface areas of a metal mold by high-frequency induction heating to a temperature above the heat distortion temperature of the resin;
- injecting molten resin into the mold, thereby flowing the molten resin composition adjacent to the inner surface area of the mold to form a skin layer consisting substantially of only the resin;
- and
- cooling the mold, opening the mold, and removing a molded article.
Dependencies are inferred from the claim text.