A method for producing a carbon fiber precursor treatment agent, an aqueous solution of a carbon fiber precursor treatment agent, a carbon fiber precursor, and a carbon fiber.

摘要

PROBLEM TO BE SOLVED: To suitably improve the effect of suppressing fusion between fibers and heat resistance in a flame-resistant treatment step of a carbon fiber precursor in a treatment agent for a carbon fiber precursor. A treatment agent for a carbon fiber precursor containing a smoothing agent, wherein the smoothing agent contains a sulfur-containing diester compound shown in Chemical formula 1 below. .. (Chemical 1) (In Ka 1, a, b: 1 to 10 integers. R 1 , R 2 : Residues obtained by removing hydroxy groups from a saturated alcohol having 17 to 32 carbon atoms, or residues obtained by removing a hydroxy group from an alkylene oxide adduct of a saturated alcohol having 17 to 32 carbon atoms. ) [Selection diagram] None