The preparation of electrophoretic ink microcapsules by using urea formaldehyde oligomer

In the process of preparing electrophoretic ink microcapsules by in-situ polymerization, oligomers instead of traditional prepolymers ( hydroxymethyl urea and dihydroxymethyl urea) of urea,formaldehyde were used as monomers of reaction, because oligomers are more likely to be adsorbed on the surface of oil phase droplets. The general problems of in-situ polymerization such as coagulating, sticking, coarse surface, low productivity etc. have been solved. The properties of viscosity and surface activity of urea-formaldehyde oligomers were studied, as well as their relationship with the encapsulation efficiency of microcapsules. The electrophoretic ink microcapsules were prepared successfully by this method.