Water dilutable binding agent composition useful for multilayer coatings for automobiles, comprises hydroxy functional polyurethane urea resin of defined characteristics and polyether polyol

摘要

A water dilutable binding agent composition comprises a hydroxy functional polyurethane urea resin of defined characteristics and a polyether polyol. A water dilutable binding agent composition (I) comprises: (A) a water dilutable hydroxyfunctional polyurethane urea resin having a urea group content(-NHCONH-) of 10-300 mmoles per 100 g solid, a urethane content (-NHCOO-) of 20-300 mmoles per 1100 g solid, an OH number of 20-250 and a number average molecular weight of 1000-20,000 g/mol and (B) 2.0-25 wt.% (w.r.t. (A) solids) of a polyether polyol having a molecular weight of 400-5000 g/mole. (A) is prepared by mixing (A1) a hydroxyfunctional compound having a number average mol. wt. of 360-8000 g/mole, (A2) a polyisocyanate and (A3) compound having a group that is reactive to isocyanate and an ionic or ion forming group, reaction of the resulting NCO group containing polyurethane prepolymer with (A4) a hydroxyfunctional monoamine and optionally a polyol in an amount such that the resulting polyurethane has the required hydroxyl number and urea and urethane group content with at least partial neutralization of the ionic groups of the resulting polyurethane before or after addition of (A4) and transfer of the resulting product to the aqueous phase. An Independent claim is included for a pigment paste having a pigment-binding agent weight ratio of 0.3:1-20:1 and optionally containing water, organic solvent and/or conventional additives.