Heterophasic polypropylene with improved stiffness/impact balance

A heterophasic polypropylene composition comprising:

• (A) 70 to 90 wt % of a crystalline isotactic propylene homopolymer matrix having a pentad concentration as determined by 13C-NMR spectroscopy of more than 96 mol % and a matrix melt flow rate (MFRM) as determined at 230° C. and 2.16 kg load according ISO 1133 in the range of 0.5 to 50 g/10 min,
• (B) 10 to 30 wt % of a predominantly amorphous propylene copolymer with 32 to 50 wt % of ethylene and/or an α-olefin with 4-10 carbon atoms, being present in the composition as dispersed particles, and
• (C) 0 to 5.0 wt % of a crystalline ethylene copolymer with an α-olefin with 3-10 carbon atoms being present in the composition as inclusions of the dispersed particles of (B),
• (D) 0 to 1.0 wt % of an alpha nucleating agent for the α- and/or γ-phase of isotactic polypropylene,
• said composition being further characterized by a total melt flow rate (MFRT) as determined at 230° C. and 2.16 kg load according ISO 1133 in the range of 0.5 to 45 g/10 min, a fraction soluble in xylene (XCS) determined at 25° C. according ISO 16152 in the range of 11 to 27 wt %, and ratio of MFRT/MFRM of ≥1.0, and
• wherein said composition has a crystalline polypropylene content with a melting point (Tm1) from DSC analysis according ISO 11357 in the range of 160 to 170° C. whereby the associated melting enthalpy (Hm1) is in the range of 70 to 100 J/g and optionally a crystalline polyethylene content with a melting point (Tm2) from DSC analysis according ISO 11357 in the range of 105 to 130° C. whereby the associated melting enthalpyl (Hm2) is less than 7.0 J/g.