| 摘要 |
Particles of active substance are encapsulated by spraying them with a thermoplastic silicone copolymer in solution in an organic solvent or in an aqueous dispersion or emulsion and removing the solvent or water by drying with hot air. The spraying/drying process employed is, for example, the Wurster process. The copolymer employed can be made up of a succession of polydiorganosiloxane segments or blocks and of organic segments or blocks (polyesters, polyethers, polyurethanes, polystyrenes, and the like). It can also be a polydiorganosiloxane grafted with organic chains. The active substance is in the form of particles with a particle size of between 50 mu m and 5 mm. It may be a catalyst, a perfume, a colorant, a cosmetic product, a medication, a plant-protection product, plant seeds, and the like. The invention is especially useful for controlling the release of active substance in an aqueous medium. |
