Patent ID: 7989542

Claim:
A process for producing a foamed thermoplastic elastomer composition, which comprises the steps of: (1) heating dynamically at least the following components (A), (B), (C) and (D), thereby producing an intermediate product: (A) 100 parts by weight of an ethylene-α-olefin random copolymer rubber, which contains at least an ethylene unit and an α-olefin unit having 3 to 10 carbon atoms, and has hardness-A defined in JIS K-6253 of 98 or smaller; (B) 5 to 130 parts by weight of a propylene homopolymer, or a random or block copolymer of propylene with ethylene and/or an α-olefin having 4 to 10 carbon atoms, said homopolymer and said copolymer containing 50 to 100% by weight of a propylene unit, wherein the total amount of all units contained therein is 100% by weight; (C) 5 to 150 parts by weight of a mineral oil softener; and (D) 0.01 to 20 parts by weight of a crosslinking agent; (2) melt-kneading at least said intermediate product with 1 to 50 parts by weight of a polypropylene resin (E), which contains 0.05 to 25% by weight of the following first propylene polymer component (E1) and 75 to 99.95% by weight of the following second propylene polymer component (E2), and has an intrinsic viscosity of 0.5 to 4 dl/g and a molecular weight distribution of 1 to 10, wherein the total amount of the first propylene polymer component (E1) and the second propylene polymer component (E2) is 100% by weight: (E1) a first propylene polymer component which has an intrinsic viscosity of 7 to 10 dl/g; and (E2) a second propylene polymer component which has an intrinsic viscosity of 0.5 to 4 dl/g; wherein each of the component (E1) and the component (E2) is a homopolymer of propylene; thereby producing a thermoplastic elastomer composition; and (3) melt-kneading at least said thermoplastic elastomer composition with (F) 0.5 to 20 parts by weight of a foaming agent.