Vandfortyndbart belægningsmiddel på basis af polyacrylater og polyisocyanater

A water-dilutable coating agent, its preparation and use are disclosed. The coating agent contains A) 40 to 95 % by weight of at least one OH group-containing binder as an aqueous dispersion of a polymer resin or of a mixture of polymer resins on the basis of olefinically unsaturated compounds. The polymer resin or said mixture have in average a hydroxyl number from 10 to 300, a numeric average of the molar mass (Mn) from 500 to 200 000 and a content of acid functionalities lower than 80 mEqu and/or a content of ethylene oxide units lower than 150 mEqu, with respect to 100 g solid resin. When acid functionalities and ethylene oxide units are both available, the sum of the acid functionalities and of the ethylene oxide units is comprised between 1 and 200 mEqu, and the acid functionalities are if required at least partially neutralised. The coating agent also contains B) 60 to 5 % by weight of one or several polyisocyanates with more than one free isocyanate group which are liquid at room temperature, if required after admixture of one or several organic solvents, the percentages by weight of A) and B) relating to the content of solid resin and adding up to 100 % by weight, and C) if required one or several additional binders, usual pigments, fillers and/or lacquer-usual additives and auxiliary substances.