| abstract |
Described herein is a method for producing a coating system on a substrate, including producing a cured basecoat film on the substrate by applying a pigmented aqueous basecoat material to the substrate and subsequently curing the basecoat material, wherein the basecoat material includes a polyether-based reaction product which is preparable by reaction ofn (a) at least one cyclic tetracarboxylic dianhydride having an aliphatic, aromatic or araliphatic radical X which bridges the two anhydride groups,n nwithn (b) at least one polyether of a general structural formula (II) nn n n n n n n n n n in whichn R is a C 3 to C 6 alkylene radical and n is selected such that the polyether (b) possesses a number-average molecular weight of 500 to 5000 g/mol, and wherein components (a) and (b) are used in the reaction in a molar ratio of 0.7/2.3 to 1.6/1.7 and a resulting reaction product possesses an acid number of 5 to 80 mg KOH/g. |