GB387918A - An improved process for producing artificial filaments with uniform shrinkage - Google Patents

Abstract

Freshly spun artificial silk is dried on perforated or permeable bobbins or spools after covering the outer surfaces of the windings with water-tight, air-impermeable jackets, the drying being effected solely from the interior and progressing from the interior to the outer layers. The inner and middle layers thus dry and shrink first, allowing the outer layers room within which to shrink as the drying proceeds. The process may be applied to freshly spun artificial silk after completion of the usual wet treatments such as washing, desulphurizing and bleaching. To obtain uniform shrinkage it is preferred to respool the dried yarn in such manner that the layers which previously were on the inside of the package become the outer layers of the new package which is moistened and then dried in the same manner as before. If desired the yarn may be twisted during the rewinding process. The air- and liquid-tight covering may be a thick wrapping of cloth. Preferably, the yarn is rewound slackly on to the second spool so as to allow the yarn to contract more easily. Yarn treated by the double drying operation with intermediate respooling is shown to be uniformly and fully shrunk to a similar extent as yarns which have been dried in skeins. When subsequently tensioned, moistened, and again dried, it shows a small and uniform extension.