METHOD FOR MANUFACTURING ACRYLONITRILIC FIBER BUNDLE AND METHOD FOR MANUFACTURING CARBON FIBER BUNDLE

The present invention has an object of providing a drawing method that has excellent process passability when the acrylonitrile fiber bundle is subjected to pressurized steam drawing particularly at high drawing ratio or at high speed. The present invention is a method for manufacturing an acrylonitrile fiber bundle, the method including the step of: drawing a fiber bundle with pressurized steam under a pressurized steam atmosphere using a pressurized steam drawing device A, the fiber bundle including a yarn spun from a spinning solution containing an acrylonitrile copolymer, the pressurized steam drawing device A having at least two zones of a preheating zone (1) provided on a fiber bundle introduction side and a heating/drawing zone (2) provided on a fiber bundle extraction side, and a sealing zone (3B) having a sealing member and separating the two zones, a pressure P1 (MPa), a pressure P2 (MPa), a difference between P2 and P1, that is, ΔP = P2 - P1, and a residence time t (sec) satisfying a relationship 1.0 ≤ ΔP/t ≤ 10, wherein the pressure P1 is a pressure in the preheating zone (1), the pressure P2 is a pressure in the heating/drawing zone (2), and the residence time t is a residence time of the fiber bundle in the sealing zone (3B), a minimum load temperature T1 (°C) of the fiber bundle (7) before being introduced into the pressurized steam drawing device (1) and a temperature T2 (°C) in the preheating zone (1) satisfying a relationship T1 - 20 ≤ T2 < T1.