Method for evaluating cellulose nanofiber dispersion

Patent metadata

Field	Value
Publication number	US-11092587-B2
Application number	US-201615550882-A
Country	US
Kind code	B2
Filing date	Feb 16, 2016
Priority date	Feb 17, 2015
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

Herein provided are methods for evaluating cellulose nanofiber dispersions, comprising the steps of: (1) preparing a cellulose nanofiber dispersion; (2) adding a color material into the cellulose nanofiber dispersion; and (3) observing the cellulose nanofiber dispersion to which a colored pigment has been added with a light microscope. The methods allow for easy evaluation of whether or not agglomerates of cellulose nanofibers exist in cellulose nanofiber dispersions, which cannot be visually determined.

First claim

The invention claimed is:

1. A method for evaluating whether or not agglomerates of cellulose nanofibers exist in a cellulose nanofiber dispersion, which cannot be visually determined, comprising the steps of:
(1) preparing a cellulose nanofiber dispersion;
(2) adding a color pigment into the cellulose nanofiber dispersion; and
(3) observing the cellulose nanofiber dispersion to which the color pigment has been added with a light microscope to determine whether or not agglomerates of cellulose nanofibers exist in a cellulose nanofiber dispersion, which cannot be visually determined, wherein the colored pigment is less transparent to light during observation with a light microscope.

2. The method of claim 1 , wherein the colored pigment has an average particle size of 10 μm or less.

3. The method of claim 1 , wherein the step (2) comprises adding a dispersion of a colored pigment to the cellulose nanofiber dispersion.

4. The method of claim 1 , further comprising the step of:
(4) determining the cellulose nanofiber (CNF) dispersion index as follows:
1) sandwich the dispersion between two glass plates to form a film having a thickness of 0.15 mm; observe the film with a microscope to measure the major axes of agglomerates; and classify the agglomerates as follows:
agglomerates having a size of 100 to 150 μm: large particles; agglomerates having a size of 50 to 100 μm: medium-sized particles; agglomerates having a size of 20 to 50 μm: small particles; and
2) calculate the CNF dispersion index by the equation below:
CNF dispersion index=(the number of large particles×64+the number of medium-sized particles×8+the number of small particles×1)÷ 2.

5. The method of claim 1 , wherein the agglomerates of cellulose nanofibers in a cellulose nanofiber dispersion are identified as a bright field.

Assignees

• Jujo Paper Co Ltd

Inventors

• Nakatani Takeshi
• Sato Shinji
• Kimura Koji

Classifications

• G01N21/84

  Systems specially adapted for particular applications · CPC title

• G01N1/30 Primary

  Staining; Impregnating {; Fixation; Dehydration; Multistep processes for preparing samples of tissue, cell or nucleic acid material and the like for analysis} · CPC title

• C08J3/05 Primary

  from solid polymers · CPC title

• C08L21/00

  Compositions of unspecified rubbers · CPC title

• A61K8/731

  Cellulose; Quaternized cellulose derivatives · CPC title