HETEROPHASIC POLYOLEFIN COMPOSITIONS HAVING IMPROVED TENSILE PROPERTIES

摘要

Polyolefin composition comprising, in percent by weight: A) 50-75% of a blend of polymers (PP) and (ECI), wherein (PP) is selected from the group consisting of: (i) propylene homopolymers; (ii) copolymers of propylene; (iii) combinations of said homopolymers (i) and copolymers (ii); (EC1) is a copolymer of ethylene and propylene or CH2=CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical, or a copolymer of ethylene, propylene and the said CH2=CHR alpha-olefin(s), containing from 20 to 35%, of ethylene; and B) 25-50% of a copolymer (ECII) of ethylene and propylene or CH2=CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical,or a copolymer of ethylene, propylene and the said CH2=CHR alpha-olefin(s), containing from 40 to 60% of ethylene; in which composition the copolymer component (ECI) is present in amounts from 23 to 45% with respect to the total weight of (A),and the intrinsic viscosity [?tot] of the fraction XS soluble in xylene at room temperature, referred to the total weight of (A) + (B), is of 3.5 dl/g or more.