| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a cellulose acetate that enables a cellulose acetate optical film, which expresses optical properties when stretched, to achieve excellent stretchability and excellent optical properties after being stretched. <P>SOLUTION: A cellulose diacetate for a retardation film has a total degree of substitution of acetyl groups of 2.27-2.56, and is characterized by having a degree of dispersion (Mw/Mn) of more than 3.0 but 7.5 or less, a degree of substitution at the 6-position of 0.65-0.85, a half width of the distribution of the degree of acetylation of 1.0-2.3, and a viscosity-average polymerization degree of 182-213. It is preferable that the cellulose diacetate for a retardation film have a 6% viscosity of 120-230 mPa s and a weight average molecular weight (Mw) of 205,000-235,000. <P>COPYRIGHT: (C)2011,JPO&INPIT |
