Method of obtaining a gas-introduced fiber-reinforced resin injection molding

Abstract

The present invention is directed to a method of obtaining a gas-introduced fiber-reinforced resin injection molding and to a molding obtained by the method. According to the present invention, there can be obtained a lightweight gas-introduced fiber-reinforced resin injection molding containing glass fibers or like fibers having excellent rigidity and strength and improved surface properties. The method includes the steps of: injecting into a die a molten resin obtained through the plasticization of a molding material; and introducing gas into the molten resin, the molding material comprising fiber-containing thermoplastic resin pellets which contain reinforcing fibers having a length of 2 mm to 100 mm, the reinforcing fibers accounting for 5% to 70% by weight of the molding material, the die including a movable die capable of advancing into and retracting from the internal cavity of the die, wherein after the injection of the molten resin into the die cavity is started, the movable die is retracted to a position where the die cavity assumes a volume corresponding to the molding, and gas is introduced into the molten resin filling the die cavity.

Dependencies are inferred from the claim text.