Patent ID: 8338543

Claim:
A thermoplastic vulcanizate elastomer obtained by dynamic vulcanization of a heterophasic polyolefin composition (I) in presence of at least: (i) an alkenyl-substituted alkoxysilane grafting agent; and (ii) water; wherein said heterophasic polyolefin composition (I) has a flexural modulus of at most 150 MPa, and comprises: (a) 5-40% of a propylene homopolymer insoluble in xylene at ambient temperature in an amount of more than 90%, or a copolymer of propylene with ethylene and/or C4-C10 alpha-olefin(s), containing 90% or more of propylene, and being insoluble in xylene at ambient temperature in an amount of more than 80%; and (b) 60-95% of an elastomeric fraction of one or more copolymer(s) of ethylene, said copolymer(s) containing from 15% to less than 40% by weight of ethylene, and being soluble in xylene at ambient temperature in an amount of more than 70%, said thermoplastic vulcanizate elastomer having compression set values from 45 to 65%, a ratio of elongation at break to compression set values over 10 and hardness shore A values below 90.