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.