High toughness propylene polymer compositions

Claim 1

A composition having a melt flow between about 0.5 and about 30 dg/min (ASTM D1238-Condition L), and a high notched impact value, said composition being obtained by blending in the absence of a peroxide 50-96% by weight of an impact-improved propylene-ethylene copolymer, 2 to 45% by weight of a high density ethylene homopolymer, 2-45% by weight of a linear low density ethylene copolymer and 0 to 30% by weight of a rubber selected from the group consisting of ethylene-propylene rubber and ethylene-propylene-diene monomer rubber, wherein: (a) said impact-improved propylene-ethylene copolymer has a melt flow (ASTM D1238-Condition L) of about 0.5 to 30 dg/min and an elastomeric propylene-ethylene copolymer content of 5-50% by weight, the copolymer fraction having an ethylene content of 30-95% by weight, which propylene-ethylene copolymer is the product of sequential polymerization of propylene and a propylene-ethylene mixture over a titanium halide-containing coordination catalyst; (b) said high density ethylene homopolymer has a density in the range from 0.941 to 0.965 g/cc and a melt index (ASTM D1238 Cond. E) in the range from 0 to 20 dg/min; (c) said linear low density ethylene copolymer is the product of polymerization of ethylene with up to 15 mole percent of at least one C 3 -C 8 alpha olefin monomer over a transition metal-based coordination catalyst and which has a density in the range from 0.912 to 0.935 g/cc and a melt index (ASTM D 1238-Condition E) in the range from 0.1 to 16; and (d) the weight ratio of high density ethylene homopolymer to linear low density ethylene copolymer is between 80:20 and 20:80.