A propylene polymer composition comprising: A) from 81 wt % to 91 wt % of a propylene ethylene copolymer containing from 1.0 wt % to 3.5 wt % of ethylene derived units having a fraction soluble in xylene at 25° C. comprised between 10 wt % and 3 wt %; and a melt flow rate ranging from 5 to 50 g/10 min; B) from 9 wt % to 19 wt %, of a copolymer of propylene and ethylene with from 21.0 wt % to 31.0 wt % of ethylene derived units; the sum A)+B) being 100; the composition having an melt flow rate ranging from 20 to 35 g/10 min; the xylene soluble fraction to 25° C. ranging from 13.0 wt % to 25.0 wt % and the intrinsic viscosity of the fraction soluble in xylene at 25° C. ranging from 0.7 dl/g to 1.9 dl/g.