The present invention relates to isocyante prepolymers containing ether and ester groups, having an isocyanate content of 1.9% to 25% by weight and based on the reaction product ofA) a polyisocyanate component containing at least one organic polyisocyanate having an average molecular weight of 168 to 1000,B) an organic polyhydroxyl component containing at least one polyhydroxyl compound containing ether and ester groups, having an average hydroxyl functionality of 2 to 3 and an average hydroxyl number of 40 to 90 and based on the esterification products ofi) polyether polyols having an average hydroxyl number of 200 to 600 withii) from 25 to 67 equivalent-%, based on the hydroxyl groups of component (i) and the carboxyl groups of component (ii), of an organic carboxylic acid component containing at least one organic monocarboxylic acid or a mixture of at least one organic monocarboxylic acid with up to 20 carboxyl equivalent-%, based on all the carboxylic acids, of polybasic organic carboxylic acids.The present invention also relates to a process for the preparation of these isocyanate prepolymers containing ether and ester groups and to their as binders or binding components in low solvent or solvent-free polyurethane coating compositions, sealing compositions or casting compositions.