| abstract |
Disclosed is a 6-position highly acetylated cellulose diacetate which has a 6-percent viscosity of 40 to 600 mPa·s and a total degree of acetyl substitution of DSt and a degree of acetyl substitution at the 6-position of DS6, in which DSt and DS6 satisfy following Conditions (1) and (2): 2.0 ≤ DSt < 2.6 0.400 ≥ DS 6 / DSt ≥ 0.531 - 0.088 × DSt n The 6-position highly acetylated cellulose diacetate is usable typically as a starting material for cellulose acylates of different acyl groups, which have a high total degree of acyl substitution, have superior optical properties, and usable typically as photographic materials and optical materials. |