Aqueous, two-component polyurethane compositions containing OH-functional polydimethylsiloxanes

摘要

The present invention relates to aqueous, two-component compositions containing A) hydroxyl-containing polydimethylsiloxanes having number average molecular weights of 400 to 3000 and an average OH functionality of >=1.8, and containing at least one structural unit of formula I) wherein R is an aliphatic, linear or branched C₁ to C₂₀ radical, R¹ is a linear or branched hydroxyalkyl radical having 2 to 10 carbon atoms and R² is either hydrogen or a linear or branched hydroxyalkyl radical having 2 to 10 carbon atoms, B) addition polymers containing hydroxyl groups and having a number average molecular weight M_n of 500 to 50,000, a hydroxyl number of 16.5 to 264 mg KOH/g solid resin, an acid number of 0 to 150 mg KOH/g solid resin and a chemically bound carboxylate and/or sulphonate group content of 5 to 417 milliequivalents per 100 g of polymer solids, and C) polyisocyanates. The present invention also relates to coatings, adhesives or sealants obtained from these compositions.