Abstract: Pressure-rupturable, oil-containing microcapsules are produced by admixing a water-immiscible, oily material containing an oil-soluble, cross-linking agent, which is either a polyfunctional isocyanate or an orthoester of a group IV element with an aqueous solution of an emulsifying agent comprising starch having ether-linked aralkyl groups, to cross-link the emulsifier and form a capsule wall at the oil/water interface of the resulting oil-in-water emulsion around the oil droplets. The emulsifying agent is the sole co-reactant for the oil-soluble cross-linking agent.

Abstract: Opacifying agents of improved structural integrity and light scattering ability are disclosed. These agents are composed of hollow, substantially spherical agglomerates having discontinuous walls composed of solid, spherical microparticles. The microparticles are produced by admixing an aqueous, partially condensed aldehyde condensation product with an oily non-solvent material and an emulsifying agent to produce a water-in-oil emulsion. Polymerization acid catalyst is then admixed with the emulsion to produce the discrete, substantially spherical and opaque, solid microparticles. After inverting the emulsion to oil-in-water form and adding oil-soluble resin adhesive, elevated temperature is used to cure the adhesive while evaporatively removing residual oily non-solvent. This yields improved agglomerate opacifying agents of high physical stability.

Abstract: Microcapsules having controlled structural integrity are produced by a process which involves admixing a thermosetting condensation polymer-containing oily solution and a polymer-containing aqueous solution and causing a chemical reaction between the polymers at the resulting oil/water interface. The so-formed microcapsules have excellent water resistance and may be employed in the formation of opacifying agents in coatings and particularly in paint films.

Abstract: Microcapsules having controlled structural integrity are produced by a process which involves admixing a thermosetting condensation polymer-containing oily solution and a polymer-containing aqueous solution and causing a chemical reaction between the polymers at the resulting oil/water interface. The microcapsules are activated and cured to provide opacifiers having excellent water resistance and may be employed as opacifying agents in coatings and particularly in paint films.