Foamable olefin thermoplastic elastomer compositions and foamed products thereof

摘要

Disclosed is a foamable olefin thermoplastic elastomer composition comprising (A) a partially crosslinked thermoplastic elastomer composition, (B) long-chain branch-containing polypropylene and (C) a foaming agent. The partially crosslinked thermoplastic elastomer composition (A) is obtained by dynamically heat-treating a mixture in the presence of organic peroxide, said mixture comprising specific proportions of a peroxide-crosslinking type olefin copolymer rubber (a), which is an ethylene/ alpha -olefin copolymer rubber composed of ethylene, an alpha -olefin of 3 to 20 carbon atoms and optionally a nonconjugated diene, and a peroxide-decomposition type olefin plastic (b), which is an alpha -olefin (co)polymer containing a specific amount of an alpha -olefin of 3 to 20 carbon atoms and having a specific MFR. Also disclosed is a foamed product obtained by heating the foamable olefin thermoplastic elastomer composition. From the foamable olefin thermoplastic elastomer composition, a foamed product having an expansion ratio of at least 2 times, being free from surface roughening caused by defoaming, being soft to the touch and showing excellent heat resistance and weathering resistance can be produced with high productivity through simplified steps.