Process for producing a resin product having a bent hollow portion and a core usable for the same process
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsYuji Tanaka, Kiyoshi Tanada
Life of this patent
Estimating the term…
Abstract
A core for producing a molded resin product having a bent hollow portion, including two-forked and multi-forked products used as parts for automobiles, and a process for producing the aforesaid resin product having a bent hollow portion by using said core.
Claims11
A core for producing a resin product having a bent hollow portion, which comprises a skeletal structure of a flexible metal tube or pipe, an elastomer provided on said skeletal structure, and a low-melting point alloy sealed within a hollow interior of said flexible metal tube or pipe, said low-melting point alloy being melted to increase flexibility of said core and solidified to add rigidity to said core;
- said flexible metal tube or pipe having such a high retention of shape that the core is not substantially deformed at least by resin flow pressure during molding, and such a high flexibility that, at the time of withdrawal of the core, the core is deformed in accordance with the shape of the molded resin product and does not injure the molded resin product and that the bending or unbending force of the core is 50 kg or less;
- and
- said elastomer is a member selected from the group consisting of a natural rubber, a silicone rubber, a fluororubber, a urethane rubber and a butadiene rubber, and having such properties that said elastomer is not adhesive and does not flow at the molding temperature of the resin product when the core is drawn out.
A process for producing a resin product having a bent hollow portion, comprising the steps:
- (1) providing a flexible core;
- (2) sealing a low-melting point alloy inside a hollow interior of said flexible core;
- (3) forming a coating on an external surface of said flexible core with an elastomer, said elastomer being non-adhesive to a resin used to form said resin product;
- (4) heating said flexible core to melt said low-melting point alloy;
- (5) preforming said flexible core into a desired shape corresponding to said bent hollow portion of the resin product;
- (6) cooling said flexible core;
- (7) installing said flexible core into a mold;
- (8) applying said resin into said mold to form said resin product, said resin directly contacting said elastomer coating on the external surface of the flexible core, said elastomer remaining on said flexible core and not flowing at a molding temperature of said resin product;
- (9) removing said resin product from said mold;
- (10) reheating said flexible core to melt said low melting point alloy;
- and
- (11) withdrawing said flexible core from said resin product, such that said elastomer is removed with said core.
A process for producing a resin product having a bent hollow portion, comprising the steps:
- (1) heating a flexible core to melt a low-melting point alloy sealed inside a hollow interior of said flexible core;
- (2) preforming said flexible core into a desired shape corresponding to said bent hollow portion of the resin product;
- (3) cooling said flexible core;
- (4) installing said flexible core into a mold;
- (5) applying said resin into said mold to form said resin product, said resin directly contacting an elastomer coating on an external surface of said flexible core, said elastomer coating remaining on said flexible core and not flowing at a molding temperature of said resin product;
- (6) removing said resin product form said mold;
- (7) reheating said flexible core to melt said low melting point alloy;
- and
- (8) withdrawing said flexible core form said resin product, such that said elastomer coating is removed with said core.
Dependencies are inferred from the claim text.