Ethylene/acrylate copolymer and the poly norbornene are designated as the base thermoplasticity elastomer

摘要

Compositions comprising a mixture of 20 to 70 parts by weight of polynorbornane, 80 to 30 parts by weight of a crystalline olefin-based polymer and a quantity of plasticizer for polynorbornane sufficient to lower its glass transition temperature to the range of rubbers. The crystalline olefin-based polymer is a polymer or mixture of polymers comprising 5 to 100 weight per cent of a copolymer of ethylene and at least one alkyl acrylate the group of which contains 1 to 8 carbon atoms, said copolymer having a melt flow rate between 0.1 and 20 dg/min, and 0 to 95 weight per cent of a copolymer of ethylene and at least one α-olefin containing at least 3 to 10 carbon atoms, said copolymer having a density between 0.89 and 0.93, a crystallinity between 15 and 50 % and a melt flow rate between 0.5 and 15 dg/min. The composition of the invention is prepared by mixing a mixture of polynorbornane, plasticizer, ethylene/acrylate copolymer, crosslinking system and, if necessary, ethylene/α-olefin copolymer, at a sufficient temperature and for a sufficient length of time to crosslink the polynorbornane.