Patent ID: 9283697
Filing Date: 2016-03-15
CPC Classification: B29B,B29C,B29K,B29L,B65D,Y10T

Claim Text:
1. A method of forming a foamed preform including: forming a non-foamed preform by injecting and filling a molten resin imbibing an inert gas in a mold cavity while applying hold pressure in the mold cavity, and heating said non-foamed preform; wherein the hold pressure is set so that the weight reduction ratio is not larger than 5%, and the non-foamed preform is obtained by injecting and filling a molten resin imbibing an inert gas in a metal mold cavity maintaining the hold pressure therein, followed by solidification by cooling; wherein weight reduction ratio=((M wherein the hold pressure is pressure caused directly by addition of the molten resin to the mold cavity.