Title:
HOLLOW MOLDED BODY
Document Type and Number:
Japanese Patent JP3387956
Kind Code:
B2
Abstract:
PURPOSE: To obtain a boss-like hollow molded body having large outer diameter wherein generation of sink mark on the rear face of the boss is restrained without regulated by thickness of a plane part by gradually changing the base shape of the boss with a curved face which is in contact with the surface of the outer periphery of the boss and a plane part of an attaching part of boss and providing a hollow in the boss.
CONSTITUTION: In a hollow molded body having a boss-like shape to be obtained by injecting thermoplastic resin, the base shape of the boss is gradually changed by a curved face where the surface of the outer periphery of the boss and a plane part of an attaching part of boss are in contact with each other, and a hollow is provided in the boss. In making the hollow molded body, a mold is formed into a predetermined shape and melted resin is injected into it. Thereafter, gas is injected into the melted resin from a gas inlet so as to form a hollow. As the hollow is kept in a pressured state until the melted resin is cooled and solidified, sink mark on the rear face of the base of the boss after cooling is restrained. Thereafter, the pressure in the hollow is made to be atmospheric pressure and the mold is opened so as to take out the product.
Inventors:
Kenichi Narita
Kenji Kohno
Kenji Kohno
Application Number:
JP6792393A
Publication Date:
March 17, 2003
Filing Date:
March 26, 1993
Export Citation:
Assignee:
Mitsubishi Engineering-Plastics Corporation
International Classes:
B29C45/00; B29C45/17; B29D22/00; B29L22/00; (IPC1-7): B29C45/00
Domestic Patent References:
| JP3258516A | ||||
| JP4246517A | ||||
| JP4259530A |
Attorney, Agent or Firm:
Takahisa Yamamoto
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