Method for preparing nanocellulose

Patent metadata

Field	Value
Publication number	US-11193239-B2
Application number	US-201816151801-A
Country	US
Kind code	B2
Filing date	Oct 4, 2018
Priority date	Apr 6, 2018
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

A method according to the present disclosure may includes preparing a urea solution by dissolving urea in distilled water, adding phosphoric acid to the urea solution, adding pulp to the solution in which urea and phosphoric acid are dissolved, heating the solution such that the urea and the phosphoric acid each react with the pulp and preparing nanocellulose by washing the pulp which is completely reacted, and then grinding the pulp, in which a weight of the phosphoric acid is 10 to 50% based on a weight of the pulp.

First claim

What is claimed is:

1. A method for preparing nanocellulose, the method comprising:
preparing a urea solution by dissolving urea in distilled water;
adding phosphoric acid to the urea solution to form a solution;
adding pulp to the solution in which the urea and the phosphoric acid are dissolved;
heating the solution such that the urea and the phosphoric acid each react with the pulp; and
preparing nanocellulose by washing the pulp which is completely reacted in a washing process, and then grinding the pulp,
wherein the preparing of the urea solution includes dissolving the urea by heating at 30° C. to 80° C., and a mixing ratio of distilled water and the urea added is a weight ratio of 1:1 to 1:3,
wherein a weight of the phosphoric acid is 10% to 50% based on a weight of the pulp,
wherein the heating of the solution is to form a carbamate group and an ester group by reacting the urea and the phosphoric acid with a hydroxyl group,
wherein the urea reacts with the hydroxyl group (—OH) of the pulp to form the carbamate group (—CONH 2 ),
wherein a phosphoric acid group reacts with the carbamate group (—CONH 2 ) to form the ester group, and
wherein the carbamate group continuously reacts with the phosphoric acid group to form an anionic functional group.

2. The method of claim 1 , wherein the heating of the solution such that the urea and the phosphoric acid each react with the pulp is performed at a temperature of 100° C. to 250° C.

3. The method of claim 1 , wherein the nanocellulose has an average diameter of 50 nm or less.

4. The method of claim 3 , wherein the nanocellulose has an average length of 2 μm or more.

Assignees

• Lg Electronics Inc

Inventors

• Lee Misun
• Kang Eunseck
• Park Koun
• Lee Dongwook
• Jung Kyungho

Classifications

• D21B1/14

  Disintegrating in mills · CPC title

• C08B1/003

  Preparation of cellulose solutions, i.e. dopes, with different possible solvents, e.g. ionic liquids (solutions used in the manufacture of monocomponent artificial filaments or cellulose or derivatives thereof D01F2/02) · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• D21H11/18 Primary

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• D21D1/00

  Methods of beating or refining; Beaters of the Hollander type (knotter screens D21F) · CPC title