Aqueous urethane resins and coating compositions having enhanced humidity resistance

摘要

Aqueous dispersions of urethane polymers are disclosed that provide water-based coating compositions with good adhesion following humidity exposure. The polyurethane is made from a first and a second polyisocyanate, the first polyisocyanate having at least one open carbon chain greater than six carbon atoms in length between two isocyanate groups, preferably at least eight carbon atoms in length. The dispersion is particularly useful as a binder resin in coating compositions having pigments that normally have a detrimental effect on adhesion.