Process for the production of dry-spun hollow polyacrylonitrile fibers and filaments

摘要

Hollow acrylonitrile fibres and filaments are prepared by dry spinning the spinning dope through a nozzle having loop-shaped nozzle orifices, the solution having a viscosity equivalent to at least 120 falling ball seconds, measured at 80 DEG C., or at least 75 falling ball seconds, measured at 100 DEG C., wherein the nozzle orifice area of the profiling nozzle is smaller than 0.2 mm2 and the maximum width of the sides of the loop-shaped nozzle is 0.1 mm and the overlap between the two ends of the sides of the loop-shaped nozzle forms an angle of from 10 DEG to 30 DEG measured from the center of the nozzle and wherein the spinning air acts on the filaments in a transverse direction to the filament take-off and the air direction forms an angle of from 80 DEG to 100 DEG with a straight line passing through the opening between the sides.