Process for preparing microcapsules

摘要

A process for the preparation of microcapsules having a wall membrane made of a polyurethane urea resin, which includes steps of mixing an oily solution and an aqueous solution, passing the resulting mixed solution through a clearance between an inner cylinder and an outer cylinder which are rotated relative to each other to form an oil-in-water type emulsion, and then forming a wall membrane on droplets of the resulting emulsion. In a preferred embodiment, the clearance between the inner cylinder and the outer cylinder is preferably in the range of 0.05 to 5 mm, more preferably 0.1 to 2 mm. The retention time of the emulsion in the clearance portion is in the range of 0.02 seconds or more, preferably 0.2 seconds or more. The inner and outer cylinders are in the form of column, optionally conical in part thereof.