| abstract |
A process for the preparation of bichromal spheres comprising (I) preparing monochromal spheres by the aggregation and coalescence of an emulsion resin with a first colorant and inorganic salt; (ii) contacting the resulting monchromal spheres with an oxidizing agent, followed by a polymerization with a vinyl monomer and a free radical initiator; (iii) forming a of the resulting monochromal spheres on a substrate; and (iv) subjecting the resulting monochromal spheres to a vapor thermal deposition with a second colorant dissimilar than the first colorant to thereby coat one hemisphere of each of said monochromal spheres thereby resulting in bichromal spheres with dissimilar colors. |