Polyolefin thermoplastic silicone elastomers employing radical cure

Polyolefin thermoplastic elastomers are disclosed which are prepared by; (I) mixing (A) a thermoplastic resin comprising more than 50 percent by volume of a polyolefin resin, said thermoplastic resin having a softening point of 23 DEG C to 300 DEG C; (B) a silicone base comprising (B') 100 parts by weight of a diorganopolysiloxane gum having a plasticity of at least 30 and having an average of at least 2 alkenyl groups per molecule, and optionally, (B'') up to 200 parts by weight of a reinforcing filler, the weight ratio of said silicone base to said polyolefin thermoplastic resin is from 35:65 to 85:15; (C) a radical initiator, present in an amount sufficient to cure said diorganopolysiloxane gum (B'); and (II) dynamically vulcanizing said diorganopolysiloxane gum, wherein at least one property of the thermoplastic elastomer selected from tensile strength or elongation is at least 25% greater than the respective property for a corresponding simple blend wherein said diorganopolysiloxane gum is not cured and said thermoplastic elastomer has an elongation of at least 25%.