Patent ID: 8378032

Claim:
An elastoplastic polyolefin composition comprising, in percent by weight: (A) 20-35% of a copolymer of propylene with 1 to 5% of at least one comonomer selected from ethylene and CH 2 ═CHR alpha-olefins where R is a 2-8 carbon alkyl; (B) 65-80% of a copolymer of ethylene and propylene containing from 57 to 75% of ethylene; a fraction XS soluble in xylene at room temperature comprising an intrinsic viscosity [η] of 3.5 to 7 dl/g; a weight ratio B/XS of at most 1.4, where B is the content of copolymer component (B), and B and XS both refer to the content with respect to the total weight of (A)+(B); and a total quantity of copolymerized ethylene from 30% to 60 wt %, wherein the elastoplastic polylefin composition is produced using a stereospecific Ziegler-Natta catalyst supported on a magnesium dihalide where components (A) and (B) are prepared in separate subsequent stages, operating in each stage, except the first stage, in the presence of the polymer formed and the catalyst used in the preceding stage; and the composition has a melt flow rate of 0.01 to 10 g/10 min., a Shore D value of at most 35, a Shore A value of at most 90, a Flexural Modulus of at most 200 MPa, an elongation at break of higher than 400%, and a fraction soluble in xylene at room temperature of 40 to 70%.