Carbon nanofiber, dispersion liquid and composition thereof

Patent metadata

Field	Value
Publication number	US-9321650-B2
Application number	US-201214238578-A
Country	US
Kind code	B2
Filing date	Oct 1, 2012
Priority date	Sep 30, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

The carbon nanofiber has a content of oxygen controlled in a range of 8% by mass to 20% by mass and excellent dispersibility in polar solvents by means of an oxidization treatment carried out on a raw material of the carbon nanofiber. The above-described oxidization treatment is preferably carried out at 100° C. or higher using an mixed acid of nitric acid and sulfuric acid in which the nitric acid concentration is in a range of 10% by mass to 30% by mass. A carbon nanofiber dispersion liquid is obtained by dispersing the above-described carbon nanofiber in a polar solvent, and a carbon nanofiber composition contains the above-described dispersion liquid and a binder component.

First claim

The invention claimed is:

1. A carbon nanofiber having a content of oxygen generated by an oxidization treatment is in a range of 8% by mass to 20% by mass,
wherein the content of oxygen is controlled in a range of 8% by mass to 20% by mass by carrying out the oxidization treatment at 100° C. or higher using an mixed acid of nitric acid and sulfuric acid in which a nitric acid concentration ratio is in a range of 10% by mass to 30% by mass, and
the carbon nanofiber used in the oxidization treatment has 98% or more of a color transmittance in toluene.

2. The carbon nanofiber according to claim 1 , wherein a fiber diameter is in a range of 1 nm to 100 nm, an aspect ratio is 5 or more, and a spacing of [002] planes in a graphite layer, which is measured using X-ray diffraction, is 0.35 nm or less.

3. The carbon nanofiber according to claim 1 , wherein, when the carbon nanofiber is made into a compact, a volume resistance value of the compact is 1.0 Ω·cm or less.

4. The carbon nanofiber according to claim 2 , wherein, when the carbon nanofiber is made into a compact, a volume resistance value of the compact is 1.0 Ω·cm or less.

5. The carbon nanofiber according to claim 1 , wherein a fiber diameter is in a range of 5 nm to 50 nm, an aspect ratio of the fiber is in a range of 10 to 1000, a spacing of [002] planes in a graphite layer, which is measured using X-ray diffraction, is in a range of 0.337 nm to 0.345 nm, a volume resistance value of a compact is 0.5 Ω·cm or less when the carbon nanofiber is made into the compact, and a peak quantitative value of a C—O bond is in a range of 2% to 5% when an XPS analysis is carried out on the carbon nanofiber.

6. A carbon nanofiber dispersion liquid obtained by dispersing the carbon nanofiber according to claim 1 in one or more dispersion media selected from polar solvents.

7. A composition comprising:
the carbon nanofiber dispersion liquid according to claim 6 ; and a binder component.

8. A composition comprising:
0.5% by mass to 8% by mass of the carbon nanofiber according to claim 1 ;
32% by mass to 94.5% by mass of a polar solvent; and
5% by mass to 60% by mass of a binder component.

9. A conductive coated film formed using the composition according to claim 7 .

Assignees

• Mitsubishi Materials Corp

Inventors

• Hagiwara Masahiro
• Sakaya Osamu

Classifications

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• D01F9/12 Primary

  Carbon filaments; Apparatus specially adapted for the manufacture thereof · CPC title

• D06M11/55 Primary

  with sulfur trioxide; with sulfuric acid or thiosulfuric acid or their salts · CPC title

• D06M11/64

  with nitrogen oxides; with oxyacids of nitrogen or their salts (with pernitric acids or their salts D06M11/50) · CPC title

• Y10T428/2918

  including free carbon or carbide or therewith [not as steel] · CPC title