THERMOPLASTIC ELASTOMER COMPOSITION FOR CORE-BACK SYSTEM FOAM INJECTION MOLDING AND FOAM INJECTION MOLDING METHOD USING THE SAME

摘要

The thermoplastic elastomer composition of the presentinvention comprises a thermoplastic elastomer which includes anethylene.cndot. .alpha. -olefin copolymer and a crystalline polyethyleneresin,wherein the crystalline polyethylene resin constitutes athree--dimensional network structure in a matrix formed by the ethylene.cndot..alpha. --olefin copolymer, an organic or inorganic blowing agent and anucleating agent, wherein the thermoplastic elastomer has a melt flowrate of 5 g/10 min or more at a temperature of 230°C and a load of 10kg, and a melt tension of 3.0 gf or more at a temperature of 210°Cand a pulling rate of 2 m/min. Also the foam injection molding methodof the present invention is a method comprising of injecting theabove-mentioned composition into a cavity space of a metal mold andthen expanding the cavity space to foam by opening the metal mold ata mold opening rate of 0.05 to 0.4 mm/sec.