| abstract |
A process for producing a polyolefin thermoplastic elastomer composition having superior rubbery elasticity, mechanical properties, etc. and also having improved processing fluidity, workability, etc. comprises (i) blendingn (A) 40 to 80% by weight of an ethylene-propylene copolymer rubber and/or an ethylene-propylene-diene terpolymer, as a soft segment component; and (B) 60 to 20% by weight of a crystalline ethylene-propylene block copolymer having an ethylene content of at least 5% by weight and a melt flow index of 0.5 to 30 g/10 minutes and/or a crystalline ethylene-propylene random copolymer having an ethylene content of at least 1.5% by weight and a melt flow index of 0.5 to 30 g/10 minutes, as a hard segment; together with [based upon 100 parts by weight of the total of (A) and (B)],n (C) 0.3 to 5 parts by weight of an organosilane; (D) 0.1 to 3 parts by weight of an organo radical-generator having a half-life period for one minute at a temperature of 170°C or higher; (E) 0 to 5 parts by weight of white carbon, and (F) 0 to 100 parts by weight of an extender oil; followed by (ii) subjecting the resulting the resulting blend to dynamic partial cross-linking. |