Patent ID: 8722808

Claim:
A polyolefin composition comprising, in percent by weight: A) 10-50% of a copolymer of propylene with at least one comonorner selected from ethylene and CH 2 ═CHR alpha-olefins, wherein R is a C 2 -C 8 alkyl, the copolymer or propylene comprising from 1 to 8% of the at least one comonomer; B) 50-90% of a blend of copolymers (b I )and (b II ), wherein copolymer (b I ) is an ethylene copolymer comprising from 18% to 40% of ethylene and (i) propylene, (ii) CH 2 ═CHR alpha-olefin(s), wherein R is a C 2 -C 8 alkyl, or (iii) a combination thereof, optionally with minor amount of a diene, and copolymer (b II ) is an ethylene/propylene copolymer comprising 55% to 85% of ethylene, optionally with minor amounts of a diene, with copolymers (b I ) and (b II ) being in a weight ratio of (b I )/(b II ) from 0.2 to 2; wherein the polyolefin composition is produced in a polymerization process in the presence of a stereospecific Ziegler-Natta catalyst supported on a magnesium dihalide, and comprises the copolymer (b I ) in an amount of 15% or more with respect to a total weight of (A)+(B), a weight ratio C 2 II /C 2 I of a content C 2 II of ethylene in the copolymer (b Il ) to a content C 2 I of ethylene in copolymer (b I ) is at least 1.8, and an intrinsic viscosity [η] of a fraction XS soluble in xylene at room temperature, referred to as a total weight of (A)+(B), is at least 2 dl/g, and the polyolefin composition has a flexural modulus equal to or lower than 150 MPa according to ISO 178 and a xylene soluble content within the range of 40 to 65% of the total weight of (A) plus (B); and wherein the weight ratio of (b II )/(A) is greater than or equal to 1.2.