Improvements in the treatment of filamentary and other products

摘要

Artificial yarns, filaments, threads, and the like are subjected while in warp formation to a stretching operation applied to the warp as a whole. Stretching is facilitated by treatment of the material with a softening agent which increases their plasticity. The process is particularly applicable to warps of cellulose acetate or other cellulose ester or ether. The warp may proceed to or from a beam or a creel of packages and it may be stretched by passing over or round rollers or between nip rollers rotating at different speeds. If desired the warp may be subjected to several stages of stretching either during a single travel or with intermediate reeling. Between successive stretching stages the warp may pass round faller-rollers which adjust the tension and maintain the threads in position. Softening agents may be incorporated in the spinning solutions, or the filaments may be immersed in the swelling agent which may be in liquid or vapour form. The filaments may be treated with the softening agent when wound on perforated supports, the agent being sucked or forced through the package. The softening agent may be aqueous dioxane, acetone, acetic acid, lactic acid, ethyl lactate, ethers of glycol, phenols, acetins, aldehydes, diacetone alcohol, thiocyanates, or zinc chloride. As shown in the drawing, yarns from a creel of packages 1, preferably large cheeses, are carried through a reed 2, over roller 3, and thence between pairs of nip rollers 4 immersed in a bath 5 containing softening fluid. The several pairs of nip rollers may each exert a stretch upon the yarns, or two pairs only may be immersed so as to apply only one stage of stretching. From the last pair of nip rollers the filaments are carried out of the softening bath and sprayed with washing fluid. Specifications 277,089, 323,790, 336,217, [all in Class 2 (ii), Cellulose &c.], and 370,430 are referred to. The Provisional Specification describes also a process of stretching in stages with one or more intermediate rest periods in which the softened threads are relieved of the stretching tension while retaining their plasticity.