Polymers of propene consist of from 50 to 99.9% by weight of an isotactic propene copolymer (A′) and from 0.1 to 50% by weight of a propene homopolymer or a propene copolymer (B′), where a) the propene copolymer (A′) consists of from 80 to 99.9 mol % of propene and from 0.1 to 20 mol % of ethene and/or a C4-C12-1-olefin, at least 80% of all propene diads are isotactic meso diads, the propene copolymer (A′) has a proportion (XS) of material soluble in xylene at 20° C. which satisfies the inequality (1) (XS) 1.9×10−11(TM)6.34+180 MPa  (2),  where in both inequalities (1) and (2) TM is the melting point in ° C., and b) the propene homopolymer or the propene copolymer (B′) consists of from 80 to 100 mol % of propene and from 0 to 20 mol % of ethene and/or a C4-C12-1-olefin, at least 55% of all regioregular propene diads are isotactic meso diads, an enthalpy of fusion &Dgr;Hm of less than 50 J/g is observed in the DSC measurement of (B′) and no crystalline ex sequences are detectable.