THERMOPLASTIC ELASTOMER COMPOSITION, FOAM MADE FROM THE SAME, AND PROCESS FOR PRODUCING FOAM

摘要

A thermoplastic elastomer composition which has a three-dimensional network structure not attributable to chemical crosslinking and is excellent in elastic recovery and flexibility; and a foam which has a high percentage of closed cells, has an even cell shape, and is excellent in elastic recovery, flexibility, and surface appearance. The thermoplastic elastomer composition is obtained by mixing (1) an EPDM, (2) a crystalline polyethylene resin, (3) a block copolymer comprising a crystalline ethylene polymer block and a block with which the EPDM is more compatible than the crystalline polyethylene resin, and an antioxidant in a given proportion and melt-kneading the mixture with a pressure kneader. The foam is obtained by adding both 1 part by weight of a wetting agent and a foaming agent to 100 parts by weight of the thermoplastic elastomer composition, mixing them with stirring, and then extrusion-foaming the resultant mixture.