| 摘要 |
PURPOSE:To obtain the titled compound having specific physical properties, high crystallinity, high perfectness of the crystal, and high degree of acetylation, by depolymerizing cellulose triacetate with an acid catalyst, and crystallizing the product to high crystallinity. CONSTITUTION:For example, a cellulose triacetate having high molecular weight and high degree of acetylation and obtained by conventional homogeneous acetylation process, is dissolved in acetic acid solution, and depolymerized with concentrated sulfuric acid catalyst. The obtained cellulose triacetate having low molecular weight and high degree of acetylation is dissolved in e.g. acetone, and a polar solvent such as methanol is added slowly to the solution to obtain a cellulose acetate having high crystallinity, low molecular weight, a number average polymerization degree of 10-50, free hydroxyl group content of <=3.2%, and a crystallinity of >=35%, and exhibiting an X-ray diffraction pattern with CuKalpha1 ray having three peaks at 8.4 deg., 10.4 deg. and 13.2 deg. of the diffraction angle 2theta, and the half width of each peak of <=0.7 deg. in terms of 2theta.
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