Pad-steam dyeing of polyacrylonitrile tows padded in nip of squeeze rollers

Claim 1

A PROCESS FOR DYEING A TOW OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF POLYACRYLONITRILE AND A COPOLYMER OF WHICH ARCYLONITRILE IS THE MAIN COMPONENT, WHICH CONSISTS ESSENTIALLY OF MOVING THE TOW IN A CONTINUOUS MANNER AND IN IMMEDIATE SUCCESSION (A) THROUGH A BATH IN THE NIP OF, AND DIRECTLY THROUGH, A PAIR OF SQUEESING ROLLERS, WHICH BATH IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF AN AQUEOUS SOLUTION OF A WATER-SOLUBLE BASIC DYESTUFF AND AN AQUEOUS DISPERSION OF A DISPERSION DYESTUFF; (B) THROUGH A PAIR OF SQUEEZING, PRESSURE SEALING ROLLERS, (C) THROUGH SUBSTANTIALLY SATURATED STEAM UNDER SUPERATMOSPHERIC PRESSURE AT ABOUT 105* TO 140*C. FOR A PERIOD OF ABOUT ONE TO TWO MINUTES, AND (D) BETWEEN A SECOND PAIR OF SWUEEZING, PRESSURE SEALING ROLLERS, BOTH PAIRS OF PRESSURE-SEALING ROLLERS SEALING THE SUBSTANTIALLY SATURATED STEAM IN A CHAMBER THROUGH WHICH SAID TOW IS MOVED, WHEREBY THE TOW IS UNIFORMLY DYED THROUGHOUT AND THE DUESTUFF IS FIXED THEREON.