JPS6231976B

PURPOSE:To obtain capsules the walls of which are made of coacervate drops without requiring a cooling process and a hardening process for water insolubilization by adding an aq. dispersion of an amphoteric hydrophobic resin having an isoelectric point to an aq. soln. of an ionic surfactant contg. a hydrophobic substance emulsification dispersed, followed by pH change. CONSTITUTION:An about 3-100mu size solid or liquid hydrophobic substance, e.g. pharmaceuticals is emulsification dispersed in an aq. soln. of an anionic (or cationic) surfactant to form an aq. dispersion. The dispersion is then made alkaline (or acidic in case of a cationic surfactant), and to the alkaline dispersion is added an aq. dispersion of an amphoteric hydrophobic resin having an isoelectric point, e.g. amphoteric polystyrene latex having NH2 and carboxyl groups introduced. By lowering the pH of this system to about 4-7 (or raising it to 9-10 in case of a cationic surfactant), complex coacervation takes place, forming thick microcapsules each consisting of a hydrophobic substance nucleus and a resin dispersion coacervate film. The capsules are dried to obtain products.