PARTICULATE POLYMERIC COMPOSITIONS AND THEIR PRODUCTION

摘要

2102128 9220441 PCTABS00017 Encapsulated particles comprise a core surrounded by a coacervate coating that comprises a low critical solution temperature polymer and a water removal depressant for the temperature of reversible insolubilisation of that polymer. The composition is either in the form of dry particles or is an aqueous dispersion at a temperature below the temperature of reversible insolubilisation of the polymer in the absence of the depressant but above the temperature of insolubilisation in the presence of the depressant. The coating dissolves when the composition is mixed with water. The composition is made by forming a dispersion of the core particles in a solution of the polymer, heating the solution to cause it to precipitate as a coacervate, and then adding the depressant. The composition can be an aqueous dispersion or dry particles.