| abstract |
Improved anionic water dispersible polyurethanes are disclosed. Polyurethane-urea polymers in aqueous dispersion are obtained by chain extending an NCO-containing prepolymer in aqueous medium. The NCO-containing prepolymer is prepared by reacting a polyisocyanate with an active hydrogen-containing compound such as a polyol and dimethylolpropionic acid (DMPA) to form a pre-prepolymer and to this is added a diamine monomer containing a pendant aliphatic, to form the prepolymer which is then dispersed in water and chain extended. The improved anionic water dispersible polyurethane polymers of the invention form excellent coatings and adhesives. |