Roylance, Abrams, Berdo & Farley
Formation of microcapsules by interfacial cross-linking, microcapsules produced, and microcapsular dispersion
 Pressure-rupturable, oil-containing microcapsules are produced by admixing a water-immiscible, oily material containing an oil-soluble, non-polymeric polyfunctional isocyanate cross-linking agent, and an aqueous solution of a polymeric emulsifying agent in the form of a water-soluble polymer containing recurring --NH.sub.2 or .dbd.NH groups or a water-soluble natural gum containing recurring hydroxy groups. An oil-in-water emulsion is formed containing the isocyanate dispersed in the form of microscopic emulsion droplets in the aqueous continuous phase containing the emulsifying agent, and a solid capsule wall is formed by the cross-linking of the emulsifying agent by the isocyanate. Emulsions utilizing the natural polymeric emulsifying agents preferably contain a viscosity lowering agent in the form of a urea-formaldehyde or alkali metal periodate in order to obtain a higher solids coat weight while at an efficient coating viscosity. 
Champion International Corporation
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Y10T B01J Y10T B41M Y10S Y10T
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Cheng H. Anthony E.
Chang Vassiliades