| 摘要 |
1334203 Microcapsules NATIONAL CASH REGISTER CO 20 March 1972 [29 March 1971] 12880/72 Heading B8C Microcapsules having a solid or liquid core surrounded by a polymer mantle are prepared by establishing an agitated 3-phase system having a continuous phase of a hydrophobic liquid vehicle, a discontinuous phase consisting of particles or droplets of the material to be encapsulated and a second discontinuous phase consisting of dispersed droplets of a solution of a hydrophobic copolymer of ethylene and vinyl acetate in which from 38 to 55% of the acetate groups have been hydrolysed to alcohol groups, either the solvent of the said solution being immiscible with the said vehicle or the said vehicle having dissolved therein a phaseseparating material. The polymer deposits around the dispersed core material to form liquid walled capsules the walls of which may be solidified, e.g. by reaction with a di- or polyisocyanate, a diacid chloride or an alkali oxide. Suitable phase-separating materials include polybutadiene, polybutene, polydimethyl siloxane, cotton seed, linseed and soya oils, mineral oils and halogenated mineral oils. The process is especially suitable for encapsulating polar materials such as aqueous solutions, hydroxy and polyhydroxy compounds and aqueous solutions thereof, solids such as methylene blue, starch, methyl cellulose and gelatine, glycols, formamide, amines and carbonates. |
