CARBON FIBER PRECURSOR FIBER BUNDLE AND PRODUCTION METHOD FOR CARBON FIBER BUNDLE

PROBLEM TO BE SOLVED: To provide a method capable of stably manufacturing a carbon fiber precursor fiber bundle having a high quality from which a carbon fiber bundle having a high performance and a high quality is obtained.SOLUTION: A production method for a polyacrylonitrile base carbon fiber precursor fiber bundle, wherein in spinning a spinning solution prepared by dissolving a polyacrylonitrile base polymer in a solvent to obtain a carbon fiber precursor fiber bundle, the spinning solution is filtrated in advance to spinning by means of a filter medium composed of fibers having a nominal filtration precision of 3 to 10 μm and an average diameter of 0.1 to 5 μm on the conditions that an average linear velocity of the spinning solution immediately before introducing the spinning solution into the filter medium and a linear velocity change rate calculated from an average linear velocity of the spinning solution in the filter medium satisfy a predetermined equation and that a retention time of the spinning solution in the filter medium resides in a predetermined range.SELECTED DRAWING: None 【課題】高性能かつ高品位な炭素繊維束が得られる高い品質の炭素繊維前駆体繊維束を安定して製造できる方法を提供すること。【解決手段】ポリアクリロニトリル系重合体が溶媒に溶解されてなる紡糸溶液を紡糸して炭素繊維前駆体繊維束を得るに際し、紡糸に先立ち、公称ろ過精度が３〜１０μｍであって、平均直径が０．１〜５μｍの繊維により構成されるフィルターろ材を用いて、フィルターろ材進入直前の紡糸溶液の平均線速度とフィルターろ材内における紡糸溶液の平均線速度から計算される線速度変化率が所定の式を満たし、かつフィルターろ材内における滞留時間が所定の範囲の条件でろ過をする、ポリアクリロニトリル系炭素繊維前駆体繊維束の製造方法である。【選択図】なし