GB459353A - Improvements in and relating to the manufacture of artificial silk - Google Patents

Abstract

<PICT:0459353/IV/1> <PICT:0459353/IV/2> Artificial silk particularly that from cuprammonium cellulose solution, is obtained by extruding the spinning solution through comparatively narrow spinneret holes within a bath containing a strongly acting precipitating liquid, a tubular member open at each end being arranged within the bath concentrically about the extruded filaments, and fresh precipitating liquid being forced by means of nozzles through the tubular member from the spinneret head side. The liquid stream issuing from the bath nozzles sets up intensive circulation of the precipitating liquid through the tubular member, into the open bath, and back into the tubular member. The tubular member may be cylindrical or conical. Stretching of the filaments is produced if the tube tapers in the direction of filament travel, owing to the acceleration of the flow of liquid. If the tube widens in the direction of the filament travel, stretching occurs owing to the increased friction of the liquid on the filaments. As shown in Fig. 1, the spinning pipe 1 with nozzle 2 can be swung into the spinning bath 3. Fresh precipitating liquid enters through nozzles 6 arranged in a ring around the spinning nozzle and is forced through the cone 7 together with the filaments 8 and through outlet 9. The filaments pass around the idly running roller 10 dipping into the coagulating liquid and capable of being readily moved by the filaments. The roller 10 is mounted in overhanging manner and is capable of being swung into position. The conical member is provided with a bulge 11 enabling it to be disposed securely on a yoke 12, 13. The proportion of fresh precipitating liquid issuing from the nozzles 6 to the quantity of already used liquid flowing into the conical member can be adjusted by varying the annular clearance between the end of the cone and the wall of the bath. If desired the roller 10 may be positively driven. As shown in Fig. 2, the spinning nozzle 21 is surrounded by the vertical conical member 23 provided with a ring 24 which can be swung about the pin 25. Fresh precipitating liquid is forced into the chamber 27, then through nozzles 28 and then through the conical tube 23. The liquid flows over the top edge of the tube into the spinning bath 26 and then again into the lower end of the tube. Excess liquid passes to the overflow device 29.