Improvements in the manufacturing of artificial filamentary materials

摘要

In wet-spinning, the freshly formed filaments are given a preliminary wash by alternately passing them several times round a pair of skew rollers at least one of which is partly immersed in a washing liquid, one or both the rollers having a pressure roller bearing thereon above the surface of the washing liquid. The process is particularly useful in the wet-spinning of an acetone solution of cellulose acetate into an aqueous solution of diethylene glycol diacetate as coagulant, one passage of the filaments through such a bath before collection being sufficient to reduce the content of coagulant to below 30 per cent (calculated on the dry weight of the filaments), whereby individual filaments have no tendency to adhere together. Filaments may be passed through a succession of such baths, e.g. 15-25 baths each containing a pair of skew rollers round which the yarn passes 3-10 turns, such washing treatment lasting about 5 mins. and reducing the content of diethylene glycol diacetate to less than 1.5 per cent. When a succession of washing baths are used, each may be supplied continuously with fresh water, or only the last few baths may have a fresh water supply which then flows through the other baths in counter current. Alternatively, after passage through a single washing bath according to the invention, the filaments may be wound up in a centrifugal box, and the cake formed, preferably still in the box, either soaked several times for 30 minutes a time in water below 40 DEG C., or washed in running water. As shown, filaments spun from the jet 2 are drawn up the setting tube 7 by godet 13, which may be fluted, entrained liquid being removed by pigtail guide 12 and inverted funnel 11 into the collecting head 10. The filaments then pass several times round the pair of skew rollers 18 partly immersed in the washing bath 14. Resting on the first roller 18 is a pressure roller 19 carried by supporting arms 20 which are freely pivoted to a bracket 21 attached to the bath. Specifications 720,187, 787,556, 787,557, 787,558, 787,559, 787,562 and 787,564 are referred to.