| abstract |
A water-dilutable coating agent, a process for preparing the same and its use are disclosed. The coating agent contains A) 40 to 95 % by weight of a film-forming, OH group-containing polyurethane resin or a mixture of such resins, available as an aqueous dispersion. The polyurethane resin or said mixture has in average a hydroxyl number from 25 to 250, a urethane group content from 2 to 20 % by weight, with respect to the solid resin, a numeric average of the molar mass (Mn) from 1 000 to 100 000 and, with respect to 100 g solid resin, a content of acid functionalities lower than 80 mEqu and/or a content of ethylene oxide units lower than 150 mEqu. When acid functionalities and ethylene oxide units are both present, the sum of acid functionalities and ethylene oxide units is comprised between 1 to 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 by 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. |