Patent ID: 8709390

Claim:
A composition comprising a hydroxyethylcellulose having hydroxyethyl groups that are non-uniformly distributed on the cellulose backbone, wherein the hydroxyethylcellulose has an unsubstituted trimer ratio (U3R) greater than 0.21 and a hydroxyethyl molar substitution in a range of about 1.3 to about 5.0, wherein the hydroxyethylcellulose composition is produced by the method comprising the steps of: A) mixing and reacting a cellulose, water, and a base reagent in an organic solvent to form a first base reagent cellulose mixture, wherein the molar ratio of water to anhydroglucose (AGU) is in a range of about 5 to 35, and wherein either (a) the molar ratio of base reagent to AGU is greater than 1.6, or (b) the molar ratio of base reagent to AGU is less than 0.4: B) (i) when (a) is used from Step A, an amount of an acid is then added to reduce the base reagent concentration so that the molar ratio of base reagent to AGU is greater than or equal to 0.6, thereby forming a second base reagent cellulose mixture, or (ii) when (b) is used from Step A, an amount of ethylene oxide is then added and reacted to form an intermediate hydroxyethylcellulose product with a hydroxyethyl molar substitution of less than 1.3, followed by additional base reagent to adjust the molar ratio of base reagent to AGU to be greater than 1.0 to form a base reagent hydroxyethylcellulose mixture: and C) adding to the second base reagent cellulose mixture from B(i) or to the base reagent hydroxyethylcellulose mixture from B(ii) an amount of ethylene oxide and reacting to form the final hydroxyethylcellulose composition.