6-position highly acetylated cellulose diacetate and process for producing the same
AssigneeDaicel Chemical Industries, Ltd.
InventorAkihiro Higuchi
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Abstract
Disclosed is a cellulose diacetate comprising a 6-position highly acetylated cellulose diacetate having a 6-percent viscosity of 40 to 600 mPa·s, and having a total degree of acetyl substitution of DSt and a degree of acetyl substitution at the 6-position of DS6, wherein DSt and DS6 satisfy following Conditions (1) and (2): 2.0≦DSt<2.6 (1) 0.400≧(DS6/DSt)≧0.531−0.088×DSt (2) The 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.
Claims9
A cellulose diacetate comprising a 6-position highly acetylated cellulose diacetate having a 6-percent viscosity of 45 to 200 mPa·s, and having a total degree of acetyl substitution of DSt and a degree of acetyl substitution at the 6-position of DS6, wherein DSt and DS6 satisfy the following Conditions (1) and (2):
- 2.0≦DSt<2.6 (1)
- 0.400≧(DS6/DSt)≧0.531−0.088×DSt (2).
A process for the production of a cellulose diacetate, comprising the step of:
- hydrolyzing a cellulose triacetate having a total degree of acetyl substitution of 2.6 or more in acetic acid, in the presence of an acetylation catalyst in an amount of 0.56 to 8.44 parts by weight to 100 parts by weight of the cellulose triacetate and in the presence of water in an amount of 22 percent by mole or more and less than 50 percent by mole relative to the amount of the acetic acid, at a temperature of from 40° C. to 90° C., to give a cellulose diacetate comprising a 6-position highly acetylated cellulose diacetate having a 6-percent viscosity of 45 to 200 mPa·s, and having a total degree of acetyl substitution of DSt and a degree of acetyl substitution at the 6-position of DS6, wherein DSt and DS6 satisfy the following Conditions (1) and (2):
- 2.0≦DSt<2.6 (1)
- 0.400≧(DS6/DSt)≧0.531−0.088×DSt (2).
Dependencies are inferred from the claim text.