GB415054A - Improvements in textile yarns and the manufacture thereof - Google Patents

Abstract

415,054. Yarns. BRITISH CELANESE, Ltd., 22, Hanover Square, London, and SOWTER, P. F. C., c/o British Celanese, Ltd., Spondon, near Derby. Feb. 15, 1933, No. 4631. [Class 120 (iii).] A composite yarn comprises a fibrous component consisting of continuous filaments all or some of which have been converted into fibrous lengths, and a continuous thread, which is completely surrounded by the fibrous component. The continuous thread may consist of continuous filaments. The yarn may be produced by stretching a continuous filament yarn doubled with a yarn of greater length, so that the continuous filament yarn is broken into fibrous lengths, and the longer yarn straightens out ; the breaking is preferably effected by passing the composite yarn through rollers rotating at differing speeds. The final yarn may be twisted to assist in the covering of the core by the fibres. The breaking may be facilitated by arranging that the component of the composite yarn to be broken is weaker than the continuous component ; or the composite yarn may be treated with a softening agent, the resistance of the two yarns to softening differing by reason of their differing twist, or by giving one yarn a preliminary treatment e.g. with an oil, so that it resists the softening agent. Alternatively, the extensibilities of the two components may be made different e.g. by adding oils or pigments to the spinning solution the extensibility may be reduced, whereas by adding high boiling point solvents and/or decreasing the draw-down it is increased. A specially strong material may be used for the continuous thread e.g. one containing filaments which have been stretched beyond their elastic limit. It may be arranged that the stretch requisite to break one component yarn into fibrous lengths is sufficient to stretch the continuous component beyond its elastic limit but without breaking it, whereby its strength is increased. A suitable stretching bath for cellulose acetate contains 47-53 per cent dioxane in water, the stretching run being 20-100 feet; other suitable stretching baths for cellulose acetate are described in Specification 397,137, and for regenerated cellulose in Specification 415,055. The components may be doubled after breakage of the filaments of one component, e.g. the two components may be led separately into a softening bath at different speeds, and drawn out together so that the slower fed yarn is stretched to breaking point, both yarns being collected and twisted, if desired, after the broken filament yarn has passed over a sharp edge or abrasive material to cut and /or lift the fibres to impart a woolly appearance. In order to enhance the woolly appearance, the yarn, after removal of the softening agent by evaporation or washing, may undergo a shrinkage treatment e.g. as in Specification 380,504, [Group IV], after which the yarn may be slackly wound. As an alternative to breaking by stretching, the yarn may be passed over abrading or cutting means.