Method of recycling carbon fiber

Patent metadata

Field	Value
Publication number	US-11976387-B2
Application number	US-202117322141-A
Country	US
Kind code	B2
Filing date	May 17, 2021
Priority date	Jul 9, 2020
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

An embodiment is a method of recycling carbon fibers that includes: preparing a carbon fiber reinforced plastic formed product that includes a carbon fiber reinforced plastic containing a carbon fiber and a resin; thermally decomposing or dissolving the resin in the carbon fiber reinforced plastic formed product by a first heating process or a first dissolving process; and winding while drawing the carbon fiber from the carbon fiber reinforced plastic formed product after the first heating process or the first dissolving process. The winding further includes thermally decomposing or dissolving a residue of the resin attached to the carbon fiber by a second heating process or a second dissolving process and adding a sizing agent to the carbon fiber after the second heating process or the second dissolving process.

First claim

What is claimed is:

1. A method of recycling carbon fibers, the method comprising:
preparing a carbon fiber reinforced plastic formed product that includes a carbon fiber reinforced plastic containing a carbon fiber and a resin;
thermally decomposing or dissolving the resin in the carbon fiber reinforced plastic formed product by a first heating process or a first dissolving process; and
winding while drawing the carbon fiber from the carbon fiber reinforced plastic formed product after the first heating process or the first dissolving process,
wherein the winding further includes thermally decomposing or dissolving a residue of the resin attached to the carbon fiber by a second heating process or a second dissolving process and adding a sizing agent to the carbon fiber after the second heating process or the second dissolving process.

2. The method according to claim 1 ,
wherein the carbon fiber is stripped upstream while the carbon fiber is wound downstream, and the residue of the resin is removed by the second heating process or the second dissolving process and subsequently the sizing agent is added after the carbon fiber is stripped and before the carbon fiber is wound.

3. The method according to claim 1 ,
wherein the resin in the carbon fiber reinforced plastic formed product is thermally decomposed by the first heating process.

4. The method according to claim 3 ,
wherein the first heating process is performed using superheated steam.

5. The method according to claim 3 ,
wherein the first heating process has a temperature of 400° C. to 500° C.

6. The method according to claim 1 ,
wherein the residue of the resin attached to the carbon fiber is thermally decomposed by the second heating process.

7. The method according to claim 6 ,
wherein the second heating process is performed using superheated steam.

8. The method according to claim 6 ,
wherein the second heating process has a temperature of 500° C. to 600° C.

9. The method according to claim 1 ,
wherein the carbon fiber is drawn to apply a tensile force of 4 to 5 MPa to the carbon fiber.

10. The method according to claim 1 ,
wherein the carbon fiber reinforced plastic formed product is a tank.

Assignees

• Toyota Motor Co Ltd

Inventors

• Watanabe Toshio
• Takayama Terufumi

Classifications

• D01F9/24 Primary

  from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08J5/042

  with carbon fibres · CPC title

• D01D10/0409

  on bobbins · CPC title

• D01F13/04

  of synthetic polymers · CPC title

• C08J2363/00

  Characterised by the use of epoxy resins; Derivatives of epoxy resins · CPC title