POLYISOCYANATE MIXTURES, A PROCESS FOR THEIR PREPARATION ANDTHEIR USE AS CROSS-LINKING AGENTS IN COATING COMPOSITIONS

摘要

The present invention relates to polyisocyanate mixtures having a) an average isocyanate functionality of at least 4.1, b) a (cyclo)aliphatically bound isocyanate group content (calculated as NCO, molecular weight = 42) of 12.0 to 20.5% by weight, c) a chemically incorporated carboxyl group content (calculated as COOH, molecular weight = 45) of 0.01 to 5.0% by weight and d) an ethylene oxide unit content arranged within terminal or lateral polyether chains of 0 to 10% by weight (calculated as C2H4O, molecular weight = 44). The present invention also relates to a process for the preparation of these polyisocyanate mixtures and to their use as cross-linking agents in aqueous coating compositions containing water soluble or dispersible binders or binder components.