Low solution viscosity cellulose triacetate and its applications thereof
AssigneeEastman Chemical Company
InventorsTim Joseph Fredercik, Darryl Aubrey Godfrey
Life of this patent
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Abstract
The invention relates to low solution viscosity cellulose triacetate and methods of making thereof. The invention also relates to films prepared from the low solution viscosity cellulose triacetate and articles containing the low solution viscosity cellulose triacetate.
Claims30
A cellulose triacetate having an average degree of acetyl substitution of from about 2.5 to about 3.0, an intrinsic viscosity of from about 1.6 to about 2.2 dl/g as measured in N-methylpyrrolidone at 65° C., and a solution viscosity as measure by ASTM D 1343-91/intrinsic viscosity ratio less than or equal to about 22.
The cellulose triacetate product produced by the process comprising
- (a) contacting dissolving grade cellulose with an acetylating catalyst and acetylating solvent to produce a mixture, wherein the catalyst is uniformly distributed throughout the mixture, wherein the amount of acetylating catalyst is from 0.5 to 5 weight parts per 100 weight parts cellulose, to produce a cellulose activate;
- and
- (b) reacting the cellulose activate with an acetylating agent in the presence of the acetylating catalyst and acetylating solvent,
- thereby producing a cellulose acetate having a solution viscosity as measured by ASTM D 1343-91/intrinsic ratio less than or equal to about 22.
The cellulose triacetate product produced by the process comprising
- (a) contacting dissolving grade cellulose containing hemicellulose impurities with an acetylating catalyst and acetylating solvent for a sufficient amount of time to break down at least about 50% of the hemicellulose impurities, wherein the amount of acetylating catalyst is from 0.5 to 5 weight parts per 100 weight parts cellulose, to produce a cellulose activate;
- and
- (b) reacting the cellulose activate produced in step (a) with an acetylating agent in the presence of the acetylating catalyst and the acetylating solvent,
- thereby producing a cellulose acetate having a solution viscosity as measured by ASTM D 1343-91/intrinsic ratio less than or equal to about 22.
Dependencies are inferred from the claim text.