A two-component coating system, containing (A) a polyisocyanate prepolymer having polyether groups bonded through allophanate groups, and (B) a mixture of polyamines in which (B1) at least 75 mol % of all NH groups originate from an amino-functional polyaspartic acid ester of the general formula (I): wherein, X represents an n-valent organic radical which is obtained by removing the primary amino groups from an n-valent polyamine; R1 and R2 independently of one another, represent organic radicals that are inert towards isocyanate groups under the reaction conditions; and n represents an integer of at least 2; and (B2) not more than 25 mol % of all NH groups originate from a cycloaliphatic diamine or aromatic diamine, and also (C) optionally a further polyisocyanate.