Aqueous polyurethane and polyurethane/poly(meth)acrylate hybrid dispersions

Abstract

The present invention relates a process of the present invention for the preparation of an aqueous composition comprising a polyurethane carrying COOH groups and/or salt groups thereof, comprises the steps of (i) reacting at least one first polyisocyanate (A1) with at least one polyol carrying at least one COOH group (BX) and optionally at least one first polyol carrying no COOH group (B1) to form a first composition (C1), (ii) treating the first composition (C1) obtained in step (i) with at least one second polyol carrying no COOH group (B2), and optionally with at least one second polyisocyanate (A2), to form a second composition (C2), and (iii) optionally treating the second composition (C2) obtained in step (ii) with at least one third-polyisocyanate (A3), to form a third composition (C3), wherein step (i) is stopped at a reaction index in the range of 0.05 to 0.94, wherein reaction index=reaction rate×[mol initial NCO groups of all A1/(mol initial OH groups of all BX and, if present, mol initial OH groups of all B1)] (formula 1) wherein reaction rate=1 minus (mol NCO groups of C1/mol initial NCO groups of all A1), and to an aqueous composition comprising a polyurethane carrying COOH groups and/or salt groups thereof obtainableby this process, to a process for the preparation of an aqueous composition comprising a polyurethane/poly(meth)acrylate hybrid polymer using the aqueous composition comprising a polyurethane carrying COOH groups and/or salt groups thereof of the present invention, to aqueous compositions comprising a polyurethane/poly(meth)acrylate hybrid polymer obtainable by the this process, to coating compositions comprising the aqueous composition comprising a polyurethane carrying COOH groups and/or salt groups thereof or the aqueous compositions comprising a polyurethane/poly(meth)acrylate hybrid polymer, and to substrates coated with these coating compositions.

Dependencies are inferred from the claim text.