Patent ID: 6022501
Filing Date: 2000-02-08
Classification: A01N

Abstract:
An improved process to make aqueous microcapsules containing a water-immiscible active ingredient having a polyamide, polyester or polyamide/polyester shell wall, the improvement which comprises incorporating free carboxylic acid groups in said shell wall by adding excess polyacid halide during shell wall formation by:(a) providing an aqueous solution comprising an emulsifier;(b) dispersing, with agitation, in the aqueous solution, a water-immiscible solution comprising a polyacid halide and a water-immiscible active ingredient to form an emulsion; and(c) adding, with agitation, to the emulsion of step (b), a polyamine, a polyol or a mixture thereof, provided that the ratio of acid halide groups to amino and/or hydroxy groups is about 2:1 to less than about 5:1 and further provided that said shell wall formation occurs essentially in the absence of a diisocyanate, a polyisocyanate, a diisocyanate prepolymer or a polyisocyanate prepolymer.