Thermoplastic polyurethanes containing polytetrahydrofuran

Thermoplastic polyurethanes based on polytetrahydrofuran, wherein the polytetrahydrofuran a mixture (i) is having a number average molecular weight between 1200 g / mol and 1500 g / mol and being greater in the mixture, the weight proportion of polytetrahydrofurans having a degree of polymerisation of less than or equal to 14 as 21 wt .-% based on the total weight of polytetrahydrofurans contained in the mixture, and less in the mixture, the weight proportion of polytetrahydrofurans having a degree of polymerization of greater than 40 than 40 wt .-% based on the total weight of the contained in the mixture polytetrahydrofurans.