Production of high strength hollow rayon fibers

Abstract From the Canadian patent

Abstract of the Disclosure, High strength hollow rayon fibers or filaments which will recover their hollow configuration after being immersed in water and subsequently dried are provided by an in-line process whereby a viscose solution containing a blowing agent is extruded into an aqueous acid coagulating bath of relatively high acid concentration. The conditions of the process result in hollow filaments that are substantially irreversible since they remain hollow and do not collapse even after repeated washing and drying cycles. The hollow filaments also possess high strength nearly equivalent to that of high wet modulus rayon fibers. Modifiers may be employed in achieving this effect, …