Hydroxypropyl-cellulose microcapsules contg oils - obtd by emulsifying crosslinking agent-oil solution in aq hydroxypropyl-cellulose soln

摘要

Oil-contg. microcapsules esp. for pressure sensitive copying paper are prepd. by (a) preparing an aqs. soln. of (I) a hydroxypropylcellulose contg. reactive OH groups, and having a decreasing water solubility as the temp. increases; (b) preparing a soln. of (II) an oil soluble crosslinking agent for I in (III) an oil; (c) emulsifying the oil soln. in the aqs. soln. to form an emulsion contg. droplets of the oil soln.; (d) heating the emulsion to a temp. above the pptn. temp. of (I), so that (I) precipitates over the droplets to form solid microcapsule walls; and (e) maintaining the emulsion at this temp. until the microcapsule walls become insoluble in water and (III). Micro-encapsulation is effected easily due to the low viscosity of the wall-forming polymer (I); wall thickness being easily controlled.