| abstract |
A polyacrylonitrile fiber manufacturing method that includes, in this order, a spinning step, a pre-drawing step, a drying step, and a post-drawing step that includes any of the following drying and drawing steps (a)-(c): (a) a step for performing drawing in mid-air, where the temperature of the thread from the thread separation point on a hot roll to the initial thread-connection point on the next roll is at least 130ºC; (b) a step for drawing where the distance from the thread separation point on a hot roll to the initial thread-connection point on the next roll is no greater than 20cm; and (c) a step in which post-drawing is performed in a hot-plate drawing zone where a hot plate is disposed between two rolls; that of these two rolls, the one that is disposed in a front position within the hot-plate drawing zone is a pre-heated hot roll; the hot plate is positioned so that the thread-connection starting point of the thread and the hot plate is no greater than 30cm from the thread separation point on the pre-heated hot roll, and drawing is performed with the surface speed of the pre-heated hot roll set to at least 100m/min. |