Patent ID: 11898276
Assignee: FORMOSA PLASTICS CORPORATION, U.S.A.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC D | IPC D

Claim 12:
13. A method of forming a carbon fiber, comprising:
performing a spinning process to a dope to obtain an as-spun fiber, wherein the dope comprises a polyacrylonitrile copolymer;
performing a first drawing operation to the as-spun fiber to obtain a filament tow;
oiling the filament tow to obtain a filament with oil by using a finishing oil, wherein a surface tension (a) and a particle size (R) of the finishing oil satisfy following equation: 20<σ+(R/2)0.5<60, the surface tension is in a range of 30 mN/m to 70 mN/m, and the finishing oil has a particle size of 10 nm to 500 nm;
performing a compacting drying process to the filament with oil, thereby obtaining a first filament;
performing a second drawing operation to the first filament, thereby obtaining a second filament; and
performing a firing process to the second filament, thereby obtaining the carbon fiber, wherein the firing process includes a stabilization treatment and a carbonization treatment.