Patent ID: 8519054

Claim:
Thermoset polyolefin elastomer obtained by static curing with water a silane-grafted thermoplastic heterophasic polyolefin composition (I) having a flexural modulus equal to or lower than 150 MPa, and comprising: (a) 5-40 weight % of a propylene homopolymer insoluble in xylene at ambient temperature in an amount of more than 90%, or a copolymer of propylene with at least one of ethylene and C 4 -C 10 alpha-olefin(s), containing at least 90% of propylene, and being insoluble in xylene at ambient temperature in an amount of more that 80% (component a); (b) 60-95 weight % of a composition of copolymers of ethylene with at least one of propylene and C 4 -C 10 alpha-olefin(s), comprising: (1) a first elastomeric copolymer containing from 15 to 32% by weight of ethylene, and having solubility in xylene at ambient temperature greater than 50% by weight, the intrinsic viscosity of the xylene soluble fraction ranging from 3.0 to 5.0 dl/g; and (2) a second elastomeric copolymer containing more than 32% up to 45% by weight of ethylene, and having solubility in xylene at ambient temperature greater than 80% by weight, the intrinsic viscosity of the xylene soluble fraction ranging from 4.0 to 6.5 dl/g; the (1)/(2) weight ratio ranging from 1:5 to 5:1, said thermoset polyolefin elastomer having a compression set value of from 30 to 65%, a ratio of elongation at break to compression set values of above 8, and hardness shore A values below 90.