to separate out above a concentration of 5 wt in the polyetherpolyols mentioned as a result of adding these polyesterpolyols the physical and mechanical properties of the purs are affected positively without the negative properties of polyesterpolyols being detectable the use of these esters which are compatible with polyetherpolyols enables targeted optimisation of the properties of polyurea polyurethanes according to the invention since polyol mixtures can be used which contain between 0 and 100 of ethers and correspondingly between 100 and 0 of esters preferably 70 to 95 wt of ethers and 5 to 30 wt of esters another advantage is that transparent materials can be prepared with these types of polyol mixtures in any of these compositions compounds for use as component b are industrially readily accessible polyisocyanates such as diisocyanatodiphenylmethane toluene diisocyanate and mixtures of these with partially carbodiimidised isocyanates in pre extended form with an nco content of 5 to 30 wt polyethers or polyesters or mixtures with the structure described under components a1 and a2 which have a hydroxyl functionality of 2 to 2 5 are used for pre extension purposes compounds for use as component c are ethanediol diethylene glycol butanediol methylpropanediol propylene glycol triethanolamine glycerol diaminoethyltoluylene or mixtures of these compounds compounds for use as component d are optionally water and or a physical blowing agent e g r 134a a mixture of hydrofluoroalkanes catalysts and optionally incorporated.