Elastomeric polypropylene

摘要

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 product and thus need not be separated into its component parts to be a useful elastomer. Also described is the diethyl ether-soluble polypropylene fraction of the direct reaction product which has about 0.5% to about 5% isotactic crystallinity and exhibits birefringence when a film formed from said fraction is viewed under crossed Nicol prisms in a polarizing microscope at about 25 DEG C. or is stretched between crossed polarizing sheets at about 25 DEG C. The diethyl ether-soluble fraction itself is a useful elastomeric material.