Patent ID: 8992728
Filing Date: 2015-03-31
Classification: C08B,C08L,D21C,D21H,Y10S,Y10T

Abstract:
1. A cellulose nanofiber production method, comprising: (1) dispersing native cellulose in a neutral reaction solution comprising 0.1 to 4 mmol/l of 2,2,6,6-tetramethyl-1-piperidine-N-oxyl and 1 to 10 mmol/l of sodium chlorite, (2) adding 1 mmol/l or less of sodium hypochlorite to the neutral reaction solution directly after step (1), (3) oxidizing the native cellulose in the neutral reaction solution to obtain an oxidized cellulose after step (2), (4) recovering the oxidized cellulose from the neutral reaction solution by purifying the oxidized cellulose by rinsing and filtration after step (3), and (5) dispersing the oxidized cellulose in a medium to obtain a cellulose nanofiber dispersion after step (4), wherein the amount of the native cellulose in the neutral reaction solution is 5% or less based on the weight of the neutral reaction solution, the cellulose nanofiber obtained by step (5) has a maximum fiber diameter of 1000 nm or less, a number average fiber diameter of 2 to 150 nm and an average degree of polymerization of 600 or more, the neutral reaction solution comprises at least one buffer selected from the group consisting of phosphate buffer, an acetate buffer, a citrate buffer, a borate buffer, a tartrate buffer and a tris buffer, and step (5) comprises a mechanical defibration treatment.