Conductive paste, conductive film, and method for producing conductive film

Patent metadata

Field	Value
Publication number	US-12305054-B2
Application number	US-201917604713-A
Country	US
Kind code	B2
Filing date	May 29, 2019
Priority date	May 29, 2019
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

Provided is a technique for a conductive paste having high conductivity and low cost. The conductive paste includes a conductive filler, a polymer, and a solvent, wherein the conductive filler includes co-continuous fibrous carbon having a three-dimensional network structure in which carbon is branched.

First claim

The invention claimed is:

1. A method for producing a conductive film, comprising:
crushing co-continuous fibrous carbon having a three-dimensional network structure in which the fibrous carbon is branched, at least a portion of the crushed co-continuous fibrous carbon having a fiber diameter of 10 nm to 200 nm, a fiber length of 300 nm to 2 μm, and a secondary particle size of 1 μm to 50 μm, the co-continuous fibrous carbon being comprised of carbonized cellulose fibers;
mixing the crushed co-continuous fibrous carbon, a polymer, and a solvent to obtain a conductive paste;
printing the conductive paste on a substrate; and
drying the conductive paste to remove the solvent to obtain the conductive film,

wherein crushing the co-continuous fibrous carbon comprises impregnating the co-continuous fibrous carbon with a solvent and then crushing the co-continuous fibrous carbon impregnated with the solvent.

2. A method for producing a conductive film, comprising:
carbonizing cellulose fibers to obtain co-continuous fibrous carbon having a three-dimensional network structure in which the fibrous carbon is branched;
crushing the co-continuous fibrous carbon, at least a portion of the crushed co-continuous fibrous carbon having a fiber diameter of 10 nm to 200 nm, a fiber length of 300 nm to 2 μm, and a secondary particle size of 1 μm to 50 μm;
mixing the crushed co-continuous fibrous carbon, a polymer, and a solvent to obtain a conductive paste;
printing the conductive paste on a substrate; and
drying the conductive paste to remove the solvent to obtain the conductive film,

wherein crushing the co-continuous fibrous carbon comprises impregnating the co-continuous fibrous carbon with a solvent and then crushing the co-continuous fibrous carbon impregnated with the solvent.

3. The method as recited in claim 2 , wherein prior to carbonizing the cellulose fibers:
freezing a dispersing liquid containing the cellulose fibers; and
drying the frozen dispersing liquid containing the cellulose fibers so as to separate the cellulose fibers from the dispersion liquid.

Assignees

• Nippon Telegraph & Telephone

Inventors

• Nohara Masaya
• Minowa Hironobu
• Iwata Mikayo
• Taguchi Hiroaki
• Komatsu Takeshi

Classifications

• H01B5/14

  comprising conductive layers or films on insulating-supports · CPC title

• H01B1/24 Primary

  the conductive material comprising carbon-silicon compounds, carbon or silicon · CPC title

• C09D11/104

  Polyesters · CPC title

• C09D11/037

  characterised by the pigment · CPC title

• B41M7/009

  using thermal means, e.g. infrared radiation, heat · CPC title