| 摘要 |
PURPOSE:To prepare the title minute particles by covering the surface of mother particles with daughter particles uniformly by stirring mother particles and daughter particles, which have been previously disintegrated with a jet mill and have each specified number average particle size, in an air stream at high speed. CONSTITUTION:Mother particles having 1-200mum number average particle size and daughter particles for forming a covering layer having <=1/5 number aver age particle size of the mother particles are prepd. and the mother particles and/or the daughter particles are disintegrated previously with a jet mill. Then, the disintegrated mother particles and/or the daughter particles are stirred at high speed in an air stream. Thus, minute particles formed to microcapsules are produced by covering the surface of the mother particles with a layer of the daughter particles. Suitable jet mill is a jet mill, 'Jet-O-Mizer(R)', etc., and suitable pressure of the high pressure air to be used during the disintegration is pref. 3-10kg/cm<2>. |
