Patent ID: 9365973
Filing Date: 2016-06-14
CPC Classification: C08B,D21C,D21H

Claim Text:
1. A method for producing cellulose nanofibers, the method comprising the steps of: (A) subjecting pulp to hydrolysis treatment and subsequent kraft cooking to prepare dissolving kraft pulp; (B) oxidizing the dissolving kraft pulp in water using an oxidizing agent in the presence of (1) an N-oxyl compound and (2) a compound selected from the group consisting of a bromide, an iodide and a mixture thereof, to produce oxidized cellulose; (C) defibrating and dispersing the oxidized cellulose to produce cellulose nanofibers, wherein acid hydrolysis treatment is not carried out between steps (A) and (B); and (D) performing a viscosity-reducing treatment of oxidized cellulose, between the steps (B) and (C), wherein the viscosity-reducing treatment is selected from the group consisting of ultraviolet irradiation, oxidative decomposition using hydrogen peroxide and ozone, hydrolysis with acid, hydrolysis with alkali, and combinations thereof.