Ept elastomers

Claim 1

Elastomers of the ethylene-propylene-termonomer type consisting essentially of (a) a first principal fraction of low molecular weight comprising from about 30% to about 85% by weight (referred to the total weight of elastomers) of molecular fractions having: an intrinsic viscosity distribution extending from about 0.2 to about 3, an average intrinsic viscosity between about 0.8 and about 1.5, an average propylene content of between about 36% and about 52% by weight, and a termonomer content of between about 0% and about 5% by weight; (b) a second principal fraction of high molecular weight comprising from about 70% to about 15% by weight (referred to the total weight of elastomers) of molecular fractions having: an intrinsic viscosity distribution extending from about 3 to about 15, an average intrinsic viscosity between about 3.5 and about 7, an average propylene content of between about 26% and about 32% by weight, and a termonomer content of between about 0% and about 5% by weight; and (c) less than about 5% by weight (referred to the total weight of elastomers) of molecular fractions having a propylene content of less than about 25% by weight and a crystallization temperature of more than 35° C.; said termonomer being a linear nonconjugated diene; said elastomers having a wide bimodal distribution of the molecular weights; and each of the two said principal fractions having a wide distribution of the molecular weights, a propylene and ethylene content which is different from that of the other principal fraction, and a distribution of propylene and ethylene which is very narrow (± 2%) around the average value contemplated for the fraction.