PREPARATION OF WATER INSOLUBLE FINE PARTICLE INCLUDING WATER SOLUBLE SOLID FINE PARTICLE

摘要

PURPOSE:To prepare a water insoluble solid fine particle in good efficiency, by a method wherein a water soluble solid fine particle is used as a core substance and encapsulated by a capsule wall comprising a water insoluble film forming substance. CONSTITUTION:A water soluble solid fine particle A such as fluoroglucine is kneaded along with a film forming substance B (e.g., polyethylene) which is melted at a temp. equal to and less than the m.p. of the fine particle A and solid at a room temp. under a temp. condition of the m.p. of the substance or more - the m.p. of the fine particle A or less. The obtained kneaded substance is added to and dispersed in a viscous liquid medium C such as silicone oil while a temp. is held to the m.p. or more of the substance B and to the m.p. or less of the fine particle A and the dispersed product is quenched to a temp. of the m.p. or less of the substance B to solidify the substance B and to form a capsule wall. The obtained cooled treated substance is treated by filtration to recover an encapulated solid fine particle which is in turn dried to obtain a product. In this case, as the medium C, one having no affinity with respect to the fine particle A and the substance B is used.