Patent GB-400938-A (GB)
Title: Improved fabrics and other materials and their manufacture
IPC: D06M11/38
Filed: 1932-04-27
Abstract: By subjecting to a saponification treatment filaments, yarns, fabrics, and other materials made of cellulose acetate or other organic esters of cellulose, of which some parts or components have been stretched to an extent different from that of other parts or components, products are obtained which are particularly adapted to give colour effects since saponification proceeds to a different extent according as the stretching has been greater or less; and the differential colour effects so produced may be associated with differential lustre effects since the extent to which the materials have been stretched determines the nature of the effect produced when the materials are subjected to a delustring treatment which may be applied before, during, or subsequent to the saponification treatment.  The differentially stretched kinds of yarn &c. associated in the fabric &c. may be of the same cellulose ester; alternatively, in order to obtain on saponification additional effects due to other causes, use may be made of differences in spinning conditions, in the acidyl value of the cellulose ester, and in the nature of the ester group attached to the cellulose.  The differential stretching of the filaments, yarns, &c. may take place during manufacture as by varying the amount of the draw-down during spinning or by employing different sizes of spinning-jet orifices; or the differential stretching may be effected after manufacture, certain of the yarns to be used in a fabric being stretched beyond the elastic limit in the dry state or when wetted with a softening liquid, the stretching being carried out on the travelling threads as in Specification 323,790, [Class 2 (ii), Cellulose &c.], or in the form of hanks &c. as in Specification 277,089, [Class 2 (ii), Cellulose &c.], or in stages as in Specification 370,430 or in warp formation as in Specification 371,461.  In a woven fabric, one type of yarn may constitute the weft, and another type the warp, or alternatively both types may be in the warp or weft or both; and the fabric may contain other types of artificial yarns, or wool, cotton, silk, &c., for example, the warp may be of cotton, viscose, &c. yarn and the weft of threads some of which are of normal type and some have been stretched to 50-100 per cent of their original length.  The process may, however, be carried out by stretching differentially sections along the length of the filament, yarn, &c. as by the method of Specification 371,910, the intermittent stretching taking place on the untwisted thread or on a thread with medium or high twisting; and the threads may be twisted after the stretching operation.  Woven fabrics made from the intermittently stretched and saponified threads exhibit a streaky and mottled effect.  The stretching to which the threads are subjected may be such that certain of the filaments are ruptured so that the product resembles a spun yarn, as described in Specification 397,137. The threads may contain natural or other artificial textiles, and they may be doubled, for example, by the method of Specification 370,040.  The saponification treatment is preferably carried out so that substantially no saponification occurs on one type of filament; it may be carried out with aqueous saponifying media, or the saponifying agent may be applied in vapour form according to Specification 313,971, [Class 2 (ii), Cellulose &c.], or in methyl or ethyl alcohol, glycol, glycerine, &c. as described in Specifications 125,153 and 313,404, [both in Class 2 (ii), Cellulose &c.], and it may be applied to threads &c. while travelling as described in Specifications 316,521 and 318,468, [both in Class 2 (ii), Cellulose &c.].  Dyeing and saponification may take place in the same bath. Specifications 343,953 and 375,424 also are referred to.