Patent ID: 7772325

Claim:
A dynamically cross-linked thermoplastic elastomer composition obtained from dynamic cross-linking of a composition comprising: (A) 10 to 50 parts by weight of a crystalline polyolefin, (B) 50 to 90 parts by weight of a modified butyl rubber composition containing a modified butyl rubber modified by reacting, to butyl rubber, (a) a compound containing, in the molecule thereof, a nitroxide free radical stable at an ordinary temperature in the presence of oxygen, (b) a radical initiator and (c) a bifunctional or higher functional radical polymerizable monomer, and (C) 0.01 to 15 parts by weight of a cross-linking agent, wherein said dynamic cross-linking is carried out at a temperature higher than the melting point of the polyolefin (A) and under a condition of shear.