炭素繊維およびその前駆体の製造方法並びに油剤付着方法

Japanese Patent JP4875238

B2

PROBLEM TO BE SOLVED: To provide a method of producing precursor fibers for carbon fibers that has excellent step-passing properties with reduced yarn breakage and occurrence of fluffing in the firing step, a method of applying finishing oil to the fibers and carbon fibers of high strength. SOLUTION: The method for applying the finishing oil is carried out in the production of the precursor fibers for carbon fibers and the finishing oil is applied in an emulsion form in which the finishing oil is emulsified and the half of the average particle diameter D2 of the emulsion particles is made larger than the radius of the pore D1 in the fiber to be finished (D1