Patent ID: 6239213
Filing Date: 2001-05-29
Classification: C08G,C09D

Abstract:
A process for the preparation of an aqueous polyurethane dispersion which comprises preparing an isocyanate terminated carboxyl group containing prepolymer by preparing a solution of a polyol in an organic solvent, adding a compound containing an ionizable group to the solution, wherein the ionizable group is an organic compound containing at least one active hydrogen, at least one group capable of salt formation and is selected from compounds having the formula,(HO).sub.m R(COOH).sub.nwherein R represents a straight or branched hydrocarbon containing 1 to 12 carbon atoms, and m and n represent values between 1 and 3, heating the mixture to a temperature ranging between 40.degree. C. and 120.degree. C., adding an isocyanate to the mixture, and stirring the mixture for a period ranging between 1 and 16 hours, neutralizing the mixture with a base, cooling the mixture to ambient temperature and dispersing the mixture in water to obtain the dispersion.