Described is an aqueous binder mixture consisting essentially of an aqueous solution and/or dispersion of a combination of a) at least one urethane-group-containing isocyanate prepolymer with blocked isocyanate groups which, in the presence of component b), is soluble and/or dispersible in water and b) a polyamine comprising at least one (cyclo)aliphatic polyamine with at least two primary and/or secondary amino groups. Also described is the use of the aqueous binder mixture in the production of coatings on heat-resistant substrates.
