| 摘要 |
Microcapsules containing a polar solvent solution or dispersion are prepared by dispersing the polar solvent solution or dispersion in a non-polar liquid containing dissolved polymeric material which is caused to precipitate and deposit around the dispersed polar solvent droplets by the addition of a second non-polar liquid which is miscible with the first but in which the polymeric material is insoluble. Suitable polymeric materials include ethyl cellulose (preferred), cellulose nitrate, cellulose acetatebutyrate, polystyrene and polystyrene copolymers, natural and synthetic rubbers, polyvinyl chloride, polyvinylidene chloride, vinyl acetate-vinyl chloride copolymers, polyethylene, polypropylene, polybutene, polyisobutylene, polyvinyl fluoride and alkyd resins. The encapsulated material may be an aqueous solution or dispersion of a dye, adhesive or chemical reagent. The capsules may be separated or partially separated from the non-polar liquid e.g. by filtration or decantation and may be insolubilized and hardened e.g. by spring-drying or by washing successively with liquids of decreasing solvent capacity for the polymer. The separated or unseparated capsules may be used to form a coating on a substrate e.g. by spraying, in particular to form sheet record materials (see Group VIII).
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