GB758442A - Improvements in cellulose acetate textile materials - Google Patents

Abstract

Textile materials are made up, at least in part, of thermoplastic fibres which consist wholly of fibres of cellulose triacetate having a sticking temperature of at least 220 DEG C., the textile materials thus having a safe ironing temperature of at least 200 DEG C. The sticking temperature is defined as the lowest temperature at which a heated iron, after standing for 10 seconds on a fabric of the cellulose acetate, causes the fabric to stick to its surface. Cellulose triacetate fibres as obtained directly by melt spinning, dry spinning, or wet spinning methods have a sticking temperature of about 200 DEG C. Such fibres, or fabrics, yarns, or other textile materials containing them may be subjected to a dry or wet heat treatment at such a temperature and for such a period of time as is sufficient to effect the required elevation of the sticking temperature. The heat treatment may be carried out at a temperature of 170-225 DEG C. for 15 seconds. Lower temperatures may be used when the heating is carried out in the presence of wet steam or water under pressure, e.g. temperatures between 120 DEG and 160 DEG C. may be used. At 160 DEG C. the time of treatment may be 5 seconds and at 120 DEG C. it may be 1-2 minutes. During the treatment, the textile material may be allowed to shrink freely or under some constraint, or shrinking may be prevented by keeping the material under tension. The treatment may be applied to batches of material or to a continuously running fabric or yarn. Yarns may be treated while travelling round thread-storage thread-advancing reels. The heat may be applied by means of a molten mixture of salts or a molten metal alloy or by means of heated plates, heated rolls, or infra-red heating devices. A fabric may be subjected to the heat treatment by pressing it against a polished or engraved plate so that it is at the same time given a glazed or patterned effect. The treatment may be applied to cellulose triacetate yarns which have been obtained by further acetylation of highly stretched acetone-soluble cellulose acetate yarn. Fabrics containing such stretched yarns may be subjected to further acetylation and then to the heat treatment. Such cellulose triacetate yarns may be subjected to dry heat at temperatures up to 285 DEG C. without undue tendency to shrink. The treated materials have good dimensional stability at high temperatures, e.g. at 230 DEG C., as well as high safe ironing temperature. In an example, cellulose triacetate filaments made by a melt-spinning process are formed into yarns. A hank of this yarn is subjected to a current of air heated to 180 DEG C. for 10 minutes and another is subjected to a current of air at 190-200 DEG C. for 5 minutes under conditions such that they can shrink freely. In both cases, fabric woven from the treated yarn has a safe ironing temperature of about 235 DEG C. The treated yarns have a high degree of dimensional stability. In another example, a fabric woven from a yarn of cellulose triacetate and having a safe ironing temperature of 180 DEG C. is held on a stenter while air at 215-220 DEG C. is blown on to it from both sides for 20 seconds. After this treatment the fabric has a safe ironing temperature of 240 DEG C. Specifications 443,707, 443,773, 448,816, 448,817, 448,917, [all in Group IV], 687,414, 719,853, 719,860, 721,674, 726,900, 731,930 and 748,772 are referred to.