Filtration method and production process of cellulose nanofiber dispersion

Patent metadata

Field	Value
Publication number	US-10850218-B2
Application number	US-201615772126-A
Country	US
Kind code	B2
Filing date	Nov 2, 2016
Priority date	Nov 2, 2015
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A cellulose nanofiber with little contaminants and a high transparency is provided. A filtration method of a cellulose nanofiber dispersion including a step of filtering a cellulose nanofiber dispersion under elevated or reduced pressure by at least one of the filtration processes: (A) a filtration process using a filter aid; (B) a filtration process using a filter media selected from the group consisting of a metal porous filter media, an inorganic material porous filter media, and a polymer porous filter media; and (C) a filtration process using both the filter aid and the filter media.

First claim

The invention claimed is:

1. A filtration method of a cellulose nanofiber dispersion comprising a step of filtering a cellulose nanofiber dispersion under elevated or reduced pressure by at least one process selected from:
(A) a filtration process using a filter aid;
(B) a filtration process using a filter media selected from the group consisting of a metal porous filter media, an inorganic material porous filter media, or a polymer porous filter media; or
(C) a filtration process using both the filter aid and the filter media, to produce a cellulose nanofiber dispersion from which contaminants are removed,
wherein the filter aid comprises a granular material having an average particle size of 1 to 150 μm.

2. The method according to claim 1 , wherein the filter aid comprises diatomaceous earth.

3. The method according to claim 1 , wherein the filter aid comprises powdered cellulose.

4. The method according to claim 1 , wherein the metal porous filter media comprises a metal filter having an average pore size of 3 to 20 μm.

5. The method according to claim 1 , wherein the polymer porous filter media comprises a polymer porous filter media having an average pore size of 6 μm or more.

6. The method according to claim 1 , wherein the polymer porous filter media comprises a polymer porous filter media having an average pore size of 8 μm or less.

7. The method according to claim 1 , comprising depositing two or more precoat layers containing the filter aid.

8. A process for producing a cellulose nanofiber dispersion comprising the step of filtering according to claim 1 .

9. A filtration method of a cellulose nanofiber dispersion comprising a step of filtering a cellulose nanofiber dispersion under elevated or reduced pressure by at least one process selected from:
(A) a filtration process using a filter aid;
(B) a filtration process using a filter media selected from the group consisting of a metal porous filter media, an inorganic material porous filter media, or a polymer porous filter media; or
(C) a filtration process using both the filter aid and the filter media, to produce a cellulose nanofiber dispersion from which contaminants are removed,
wherein the filter aid comprises diatomaceous earth or powdered cellulose.

10. The method according to claim 9 , wherein the metal porous filter media comprises a metal filter having an average pore size of 3 to 20 μm.

11. The method according to claim 9 , wherein the polymer porous filter media comprises a polymer porous filter media having an average pore size of 6 μm or more.

12. The method according to claim 9 , wherein the polymer porous filter media comprises a polymer porous filter media having an average pore size of 8 μm or less.

13. The method according to claim 9 , comprising depositing two or more precoat layers containing the filter aid.

14. A process for producing a cellulose nanofiber dispersion comprising the step of filtering according to claim 9 .

Assignees

• Jujo Paper Co Ltd

Inventors

• Nakayama Takeshi
• Sato Shinji
• Yamaguchi Masato
• Takaichi Satoshi

Classifications

• D21H11/18

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• B01D2239/1241

  Particle diameter · CPC title

• D21C9/18

  De-watering (de-watering in general F26B); {Elimination of cooking or pulp-treating liquors from the pulp}(D21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B) · CPC title

• B01D2239/1216

  Pore size · CPC title