Polyolefin compositions

A process for producing a polyolefin composition comprising:

• polymerizing olefins in at least two sequential polymerization stages with each subsequent polymerization stage being conducted in the presence of the polymeric material formed in the immediately preceding polymerization stage thereby producing the polyolefin composition comprising:
• comprising, in percent by weight referred to the sum of component 1) and 2):
• 1) 75-85 wt % of a propylene homopolymer or copolymer of propylene with at least one of ethylene and C4-C10 α-olefin(s), the homopolymer or copolymer having melting temperature equal to or higher than 150° C., and
• 2) 15-25% of a copolymer of ethylene with at least one C4-C10 α-olefin containing from 20 to 30% of said C4-C10 α-olefin;
• said composition having
• (i) a value of MFR at 230° C., 2.16 kg of from 5 to 10 g/10 min,
• (ii) a total content of ethylene of from 10 to 20%,
• (iii) a total content of C4-C10 α-olefin of from 2 to 8%,
• (iv) a ratio XStot/XSm of the total fraction soluble in xylene at room temperature to the fraction soluble in xylene at room temperature of the component (1) of from 5 to 15, and
• (v) a value XSIVtot of the intrinsic viscosity of the total fraction soluble in xylene at room temperature of 1.5 dl/g.