POLYOLEFINIC COMPOSITIONS

摘要

A polymer composition comprising (percent by weight): a) 57%-74%, of a crystalline propylene polymer having an amount of isotactic pentads (mmmm), measured by 13C-MNR on the fraction insoluble in xylene at 25° C., higher than 97.5 molar % and a polydispersity index ranging from 5 to 10; b) 8 to 15%, of an elastomeric copolymer of ethylene and propylene, the copolymer having an amount of recurring units deriving from ethylene ranging from 30 to 50%, and being partially soluble in xylene at ambient temperature; the polymer fraction soluble in xylene at ambient temperature having an intrinsic viscosity value ranging from 2.5 to 3.5 dl/g; and c) 18-28%, of ethylene homopolymer having an intrinsic viscosity value ranging from 1.5 to 4 dl/g; said composition having a value of melt flow rate ranging from 35 to 60 g/10 min, and the amount of hexane extractables lower than 4.0 wt %.