Propylene homopolymers, wherein, in their separation according to tacticity by first dissolving the polymers in boiling xylene, then cooling the solution to 25° C. at a cooling rate of 10° C./h and then, with ascending temperature, separating the propylene homopolymers into fractions of different tacticity, either one or more of the conditions that i) the fraction of propylene homopolymers which remains undissolved on heating the cooled propylene homopolymer solution to 112° C. is greater than 20% by weight or ii) the fraction of propylene homopolymers which remains undissolved on heating the cooled propylene homopolymer solution to 117° C. is greater than 8% by weight or iii) the fraction of propylene homopolymers which remains undissolved on heating the cooled propylene homopolymer solution to 122° C. is greater than 1% by weight, are satisfied.