Patent ID: 10355280

Abstract:
A manufacturing method which includes: (1) an alkali cellulose reaction step wherein a mixed solvent having a mixing ratio (a mass ratio) of an alcohol having a carbon number of 3 or less and water of 75:25 to 95:5 is used, and the concentration of the base to the water is 25 to 40 mass %; (2) an etherification reaction step wherein a reaction is carried out under an excess base of 0.2 to 0.5 moles per unit of an anhydroglucose of the cellulose; (3) a neutralization step wherein acid is added to adjust the pH of the reaction mixture to 6.0 to 8.0; and (4) a heating step wherein the mixed solvent is removed, and a base is added to adjust the pH of the reaction mixture to 8.0 to 9.0, and then a heat treatment is performed at 40 to 70° C. for 30 to 120 minutes.