METHOD AND APPARATUS FOR STRETCHING FIBER BY USING PRESSURIZED STEAM, AND METHOD FOR PRODUCING ACRYLIC PRECURSOR FIBER BUNDLE FOR CARBON FIBER

PROBLEM TO BE SOLVED: To provide a method for stretching a fiber, which is capable of suppressing the formation of fluffs even if performing high magnitude stretching, obtaining a fiber of a thin-fineness, and obtaining a fiber bundle having a large total fineness, etc., and especially suitable for actually producing an acrylic precursor fiber bundle for carbon fibers, and a stretching apparatus using pressurized steam. SOLUTION: The method for controlling the temperature of the fiber bundle introduced into a stretching bath, and the water content, pressure, and temperature of the pressurized steam so as to condense the pressurized steam supplied into the stretching bath of the stretching apparatus using pressurized steam on the surface of the fiber bundle introduced into the stretching bath and stretch the fibers by the plastisizing effect of the condensed water formed on the surface of the fiber bundle, and the stretching apparatus using pressurized steam, which is capable of controlling them are provided. COPYRIGHT: (C)2008,JPO&INPIT