Patent ID: 8394497
Filing Date: 2013-03-12
Classification: B01J,Y10T

Abstract:
1. A process for microencapsulating a substance, wherein the process comprises the steps of: A. mixing a first amount of a film-forming, cross-linkable, hydrolyzed polymer and an organic, nonpolar solvent for the polymer, wherein the solvent is not a solvent for particles of the substance; B. agitating the mixture to form a solution of the polymer in the solvent; C. adding particles of the substance to the solution under conditions of continuing agitation, wherein the substance particles are dispersed in the solution; D. inducing a phase separation of the solution, wherein the polymer is separated from the solution and a film-like sheath of the polymer is formed and coated on each substance particle; and E. adding a second amount of a polyisocyanate cross-linking agent to the solution under conditions of continuing agitation, the mass of said second amount being greater than the mass of said first amount, wherein the film-like sheath on each substance particle cross-links and hardens around each substance particle, whereby the microencapsulated substance particles have improved impermeability to moisture as compared to substance particles that are microencapsulated using other film-forming polymers.