| 摘要 |
PURPOSE:To obtain microspherical cellulose acetate powder in good efficiency, by mixing an organic solvent solution of cellulose acetate with an aqueous medium containing a dispersant, a surfactant and an antifoaming agent by agitation and evaporating the solvent by heating. CONSTITUTION:An organic solvent solution of cellulose acetate is mixed by agitation with an aqueous medium containing a dispersant, a surfactant, and an antifoaming agent under a condition such that the peripheral speed of the tips of impellers is 450m/min or above and the agitator speed is 2,000rpm for 10sec or longer, and the aqueous medium containing the formed suspended particles is heated to vaporize the organic solvent. In this way, microspherical cellulose acetate powder of an average particle diameter of 2-37mu can be obtained. The degree of substitution of the cellulose acetate used is preferably 1.2-3.0. Cellulose acetate of a degree of substitution of 1.2 or below requires a long saponification time, which is disadvantageous from the economical viewpoint. The degree of polymerization is suitably 80-360. |
