Polyurethane dispersions for coating with barrier features

摘要

Preparing water-dispersible polyurethane, comprises reacting together 5-60 wt.% of a difunctional polyisocyanate containing polyisocyanate component, 20-90 wt.% of an aromatic structure containing polyol-, polythiol- and/or polyamine-component, 1-15 wt.% of a hydrophilic component, of which compounds exhibit at least one isocyanate-reactive group in addition to at least one hydrophilic group, 1-40 wt.% of a hydrophobic component and 0-25 wt.% of further isocyanate-functional- and/or isocyanate-reactive components. Independent claims are included for: (1) a water-dispersible polyurethane obtained by the above process; (2) producing aqueous dispersion containing water-dispersible polyurethane, comprising dispersing the obtained product in water after the reaction of the components, where before, during or after the dispersion in water, a chain extension is carried out by reaction with compounds of isocyanate-functional- and/or isocyanate-reactive component and/or deprotonation of acid groups by adding a neutralizing agent; (3) a polyurethane dispersion obtained by the above process; (4) a binder combination comprising water-dispersible polyurethane and/or polyurethane dispersion; and (5) a coating obtained by using binder combination.