| abstract |
Dual cure coating compositions having a resin solids content of 40 to 80 wt. %, said resin solids content consisting of n (a) 30 to 90 wt. % of at least one hydroxy-functional polyester urethane having olefinic double bonds, n (b) 0 to 60 wt. % of at least one binder other than the polyester urethane (a) and/or at least one reactive diluent, and n (c) 10 to 50 wt. % of at least one cross-linking agent for hydroxy-functional components (a) and optionally (b), n wherein the at least one polyester urethane (a) has a number average molecular mass of 1000 to 5000 and a hydroxyl value of 80 to 250 mg KOH/g, contains olefinic double bonds corresponding to an olefinic double bond equivalent weight of 250 to 2000 and is obtainable by the reaction, which proceeds with consumption of all isocyanate groups, of a component (a1) containing at least one isocyanate group and at least one olefinic double bond with a non-aromatic polyester polyol (a2) having a calculated molecular mass of 600 to 1400, an acid value of 0 to 30 mg KOH/g and a hydroxyl value of 250 to 600 mg KOH/g at a calculated hydroxyl functionality of 4.5 to 10, and wherein the sum of weight percentages of components (a) to (c) is 100 wt. %. |