Abstract: A masterbatch composition comprising (percent by weight): A) 50%-90% of a crystalline polypropylene component comprising: AI) from 25% to 75% of a fraction having a melt flow rate MFRI of from 0.1 to 10 g/10 min.; and AII) from 75% to 25% of a fraction having a melt flow rate value MFRII equal to or lower than 100 g/10 min.; wherein the ratio MFRI/MFRII is from 5 to 60; and B) 10%-50% of a copolymer component of ethylene and at least one C3-C10 ?-olefin, containing from 15% to 50% of ethylene; said masterbatch composition having a value of the intrinsic viscosity [?] of the fraction soluble in xylene at room temperature equal to or higher than 3.5 dl/g, is added to polyolefin materials to obtain final compositions suitable for injection molding.

Abstract: Catalyst components for the polymerization of olefins CH2?CHR, wherein R is hydrogen or a hydrocarbon radical having 1–12 carbon atoms, comprising Mg, Ti, Cl, OR groups, where R is a C1–C10 alkyl group optionally containing heteroatoms, and an ether having two or more ether groups, characterized by the fact that the Mg/Ti weight ratio is lower than 3 from 2 to 6.5 the Cl/Ti weight ratio is from 1.5 to 6, the OR/Ti weight ratio is from 0.5 to 3.5 and at least 50% of the Titanium atoms are in a valence state lower than 4. The said catalyst components allow the preparation of ethylene copolymers with a low content of xylene soluble fractions.