Post-treatment of polyurea microcapsules
AssigneeStauffer Chemical Company
InventorHerbert B. Scher
Life of this patent
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Abstract
Post-treatment of microcapsules having polyurea walls with ammonia or amines to reduce the residual isocyanate level and modify permeability of the microcapsule wall. Flowable formulations of the polyurea microcapsules then can be stored at pH values below 8 without generating carbon dioxide from the reaction of residual isocyanate groups with water.
Claims9
Method of reducing residual isocyanate level in polyurea microcapsules comprising post-treatment of said polyurea microcapsules with an excess of ammonia or an amine.
In the process of microencapsulation of core material by interfacial polymerization of an organic isocyanate intermediate, the improvement comprising post-treating formed polyurea microcapsules with an excess of ammonia or an amine.
Improved polyurea microcapsules having reduced residual isocyanate levels and modified permeability of the microcapsule wall prepared by post-treatment of the formed polyurea microcapsules with an excess of an amine or ammonia.
Dependencies are inferred from the claim text.