Sulfate ester modified cellulose nanofibers and method for producing cellulose nanofibers

Patent metadata

Field	Value
Publication number	US-11535682-B2
Application number	US-201816477957-A
Country	US
Kind code	B2
Filing date	Jan 16, 2018
Priority date	Jan 16, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

Sulfate ester modified cellulose nanofibers having an average fiber diameter in the range of 1 nm to 500 nm, and having sulfate ester modified hydroxyl groups on surfaces of the cellulose nanofibers. A method of producing cellulose nanofibers that are nanosized, that have a high crystallinity degree, and that have large aspect ratios, the method being a chemical method that does not require any physical pulverization, that is energy-saving, and that can be performed under mild reaction conditions. A method of producing modified cellulose nanofibers including modifying the surfaces of the cellulose nanofibers through esterification or urethanization. A method of producing cellulose nanofibers includes impregnating cellulose with a fibrillation solution containing dimethylsulfoxide, at least one carboxylic acid anhydride selected from acetic anhydride and propionic anhydride, and sulfuric acid to fibrillate the cellulose.

First claim

The invention claimed is:

1. Cellulose nanofibers, which have an average fiber diameter in the range of 1 nm to 500 nm, and which have sulfate ester modified hydroxyl groups on surfaces of the cellulose nanofibers,
wherein the cellulose nanofibers have a sulfur content of from 1.3 wt % to 35 wt %,
wherein a viscosity of an aqueous dispersion of the cellulose nanofibers of 0.3 wt % aqueous dispersion of the cellulose nanofibers, at 25° C., number of revolutions 2.6 rpm, is from 500 mPa·s to 25,000 mPa·s, and
wherein a thixotropy index (TI value) (2.6 rpm/26 rpm) of the 0.3 wt % aqueous dispersion of the cellulose nanofibers at 25° C. is from 3 to 30.

2. Cellulose nanofibers, which have an average fiber diameter in the range of 1 nm to 500 nm, and which have sulfate ester modified hydroxyl groups on surfaces of the cellulose nanofibers,
wherein the cellulose nanofibers have a sulfur content of from 1.3 wt % to 35 wt %, and
wherein a TI value (2.6 rpm/26 rpm) of the 0.3 wt % aqueous dispersion of the cellulose nanofibers at 25° C. is from 3 to 30.

3. Cellulose nanofibers, which have an average fiber diameter in the range of 1 nm to 500 nm, and which have sulfate ester modified hydroxyl groups on surfaces of the cellulose nanofibers,
wherein the cellulose nanofibers have a sulfur content of from 1.3 wt % to 35 wt %, and
wherein a viscosity of an aqueous dispersion of the cellulose nanofibers of 0.3 wt % aqueous dispersion of the cellulose nanofibers, at 25° C., number of revolutions 2.6 rpm, is from 500 mPa·s to 25,000 mPa·s.

Assignees

• Kri Inc
• Yokogawa Electric Corp

Inventors

• Lin Lianzhen
• Hori Masanori
• Maruta Ayako

Classifications

• C08B15/00

  Preparation of other cellulose derivatives or modified cellulose {, e.g. complexes} · CPC title

• C08B7/00 Primary

  Preparation of cellulose esters of both organic and inorganic acids {(rendering cellulose suitable for esterification C08B1/02)} · CPC title

• C08L1/10

  Esters of organic acids {, i.e. acylates} · CPC title

• C08L1/04 Primary

  Oxycellulose; Hydrocellulose {, e.g. microcrystalline cellulose} · CPC title

• C08B5/14 Primary

  Cellulose sulfate · CPC title