Patent ID: 11905354
Assignee: LG CHEM, LTD.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC C  D | IPC C  D

Claim 0:
1. A method of preparing an acrylonitrile-based copolymer for a carbon fiber, the method comprising:
preparing a reaction solution including a monomer mixture and an organic solvent, wherein the monomer mixture comprises a sulfonate-based monomer represented by Chemical Formula 1, a carboxylic acid-based monomer, and an acrylonitrile-based monomer; and
subjecting the reaction solution to polymerization,
wherein the polymerization comprises:
primary polymerization of the reaction solution at a first temperature; and
secondary polymerization of the reaction solution at a second temperature higher than the first temperature,

wherein the monomer mixture comprises 0.55 to 1.6 mol % of the sulfonate-based monomer represented by Chemical Formula 1 based on a total molar amount of the monomer mixture:, wherein, in Chemical Formula 1,
R is hydrogen or a C1 to C3 linear alkyl group,
L is a C1 to C3 linear alkylene group, and
X is an alkali metal.