| abstract |
PURPOSE:To obtain the title composite particles contg. homogeneously a useful substance and whose particle size is uniform and shape is regular, by bringing a soln. of a useful substance into contact with specified swellable synthetic resin particles to swell said particles and drying the particles. CONSTITUTION:A soln. is obtd. by dissolving a useful substance, e.g., a dyestuff when composite particles obtd. are used as a coloring filler for plastics, a photochromic compd. when it is used as photochromic particles and a dyestuff when it is used as a toner for electrophotography (e.g., a blue color No.403) (A) in a solvent (e.g., isopropanol) (B). This soln. is brought into contact with a swellable synthetic resin particle which is swollen 1.01-100-fold, pref. 3-20-fold when brought into contact with the component B and hose particle size is 0.1-100mum in a non-swollen state (e.g., polymethyl methacrylate-divinylbenzene crosslinked particles) (C) to penetrate a soln. of component A into the component C and to swell the component C and thereafter the component B is removed by drying. |