Heterophasic propylene copolymers with stiffness/impact/flowability balance

Abstract

Heterophasic propylene copolymer (HECO) comprising: (a) a polypropylene matrix comprising: (a1) a first propylene homopolymer fraction (PPH1) with a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of >200 to 500 g/10 min, (a2-1) a second propylene homopolymer fraction (PPH2) with a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of >30 to ≦200 g/10 min or, (a2-2) a second propylene homopolymer fraction (PPH2) with a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of >5 to ≦30 g/10 min and, (a3-1) a third propylene homopolymer fraction (PPH3) with a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of 0.03 to ≦5 g/10 min, if the second propylene homopolymer fraction is fraction (a2-1) or, (a3-2) a third propylene homopolymer fraction (PPH3) with a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of >30 to ≦200 g/10 min, if the second propylene homopolymer fraction is fraction (a2-2), wherein the polypropylene matrix has a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of 30 to 500 g/10 min and a xylene cold soluble fraction determined at 23° C. according to ISO 6427 in the range of 0.5 to <2.0 wt %, (b) an elastomeric propylene copolymer dispersed in said matrix, wherein (i) said heterophasic propylene copolymer has a melt flow rate MFR2 (230° C.) measured according to ISO 1133 in the range of 25 to 200 g/10 min and, (ii) as the amorphous phase (AM) of the cold soluble fraction (XCS) of the heterophasic propylene copolymer has an intrinsic viscosity measured according to ISO 1628-1 (at 135° C. in tetraline) of ≧2.0 dl/g, and a process for its preparation.

Dependencies are inferred from the claim text.