| 摘要 |
1,198,956. Making microcapsules. NATIONAL CASH REGISTER CO. 7 Jan., 1969 [29 Jan., 1968], No. 947/69. Heading B8C. [Also in Division C3] Microcapsules are produced by dispersing in an aqueous solution of poly vinyl alcohol a solution in a water-immiscible liquid of an alkylene glycol cyclic borate ester and keeping the dispersion agitated for a time sufficient to allow the formation of a complex between the polymer and the ester at the liquid-liquid interface which encapsulates the dispersed droplets. The coatings may subsequently be hardened, e.g. by treatment with a transition metal salt, e.g. vanadyl sulphate. Preferred esters are those of the general formula in which each R is a hydrogen atom or a C 1-7 alkyl group, at least one R being alkyl. A phase separation inducing agent, e.g. sodium, magnesium or ammonium sulphate or gum arabic, may be included in the aqueous phase to assist capsule formation. Numerous core materials (i.e. the water-immiscible liquid in which the borate ester is dissolved) are mentioned, including animal, vegetable, mineral and synthetic oils. |
