Disclosed is a composition comprising at least one polyol component (a) having an OH group content of 3% to 15% by weight relative to the total weight of the polyol component, and at least one isocyanate component (b) having an isocyanate group content of 5% to 15% by weight relative to the total weight of the isocyanate component. The polyol component (a) comprises at least one OH group-containing polyurethane prepolymer that is the product of a reaction between at least one compound a1. of the general formula (I) HO—R1—X—R2—OH  (I) and at least one di- or polyisocyanate a2. The isocyanate component (b) comprises at least one di- or polyisocyanate-terminated polylactone prepolymer. The composition can be used as erosion-resistant coating material.