| 摘要 |
Microcapsules containing water and dissolved compounds (first aqueous phase) in a solid cover of a polymer material are formed by (a) emulsifying the aqueous material or hydrophibic component in a soln. of a polymer, the solvent for the polymer being immiscible with water, and having a b.p. below 100 degrees C, (b) emulsifying the formed emulsion in an aqueous soln. of a hydrophilic colloid (second aqueous phase), and (c) removing the solvent for the polymer from the system by evaporation, as in BE.634,668. The improvement comprises preventing the transfer of a dissolved compound from the first aqueous phase to the second aqueous phase by dissolving the compound in the second aqueous phase at the same or a higher concentration than present in the first aqueous phase. The microcapsules are suitable for encapsulating materials such as catalysts for chemical reactions, develops for use in silver halide photography, pH-controlling compounds, leuco dyes, diazonium componds, or couplers for diazonium compounds. The present modified process prevents the transfer of dissolved compounds from the first aqueous phase to the second aqueous phase. In this manner, the concentrations of dissolved compounds in the first aqueous phase is held constant, so that the aqueous soln. which is encapsulated has a definite concentration. |
