A fractionable elastic polypropylene which has an inherent viscosity of 1.5-9, exhibits no yield point, has a tensile set not exceeding 150% and contains about 10 to 80% by weight of a diethyl ether-soluble fraction having an inherent viscosity exceeding 1.50. This polypropylene is a direct reaction...http://www.google.fr/patents/US4335225?utm_source=gb-gplus-shareBrevet US4335225 - Elastomeric polypropylene
