GB397509A - Improvements in or relating to the production of artificial filaments or like extruded materials - Google Patents

Abstract

Artificial filaments are stretched continuously with production, the stretching force being prevented wholly or partly from extending back to the liquid filaments at the point of extrusion by a tensioning device or devices applied initially at points which are successively brought closer to the point of extrusion. In this manner stretching of the filaments when in a condition too weak to withstand the shock of the initial application of the tensioning means may be effected. If desired, tensioning devices more remote from the extrusion orifices may be removed after a tension device nearer to the extrusion orifices has been brought into action. The tensioning devices may be rod or freely mounted rollers, and in the case of dry spinning, they may be disposed at intervals along the whole path of the filaments through the evaporative atmosphere or within a range where the filaments contain more than 50 per <PICT:0397509/IV/1> <PICT:0397509/IV/2> <PICT:0397509/IV/3> <PICT:0397509/IV/4> cent of solvent. As shown in Fig. 1, filaments 14 are extruded downwardly from a nozzle 13 in a casing 10 through which passes a counter-current of evaporative medium, and pass out of the casing to a withdrawal roller 17 rotating at a greater peripheral speed than the rate of extrusion. They are further stretched by a roller 18 and then wound by the cap spinning device 19. Within the casing are a number of fixed rods 27 and movable rods 28, 33, the latter being operated by handles 31, 32. When spinning is started the tension rods are in the inoperative position. The movable rod 33 is then pushed into contact with the filaments, and the rods 28 are subsequently brought into action so as to apply the tension at points which approach successively closer to the p point of extrusion. As shown in Figs. 2 and 3, a number of rods are disposed on opposite sides of the filaments and pivoted so that they may be brought into contact with the filaments and constitute tensioning devices. The rods are jointed together and are operated simultaneously by the handle 50. They are so mounted that the rods more remote from the nozzle contact with the filaments before those nearer to the nozzle and when the rods nearest to the nozzle are in operation, those remote therefrom are moved out of contact with the filaments. If desired, the filaments may be lubricated before coming into contact with the tensioning devices. The stationary rods 27, shown in Fig. 1, may be hollow in construction and supplied with lubricant which passes through perforations 41 as shown in Fig. 1a and an absorbent fabric coating 42 to the filaments contacting therewith. The device may be used in dry or wet spinning processes for the production of threads of cellulose acetate, nitrate, or other cellulose ester, ethyl cellulose or other cellulose ether, or regenerated cellulose threads from viscose, cuprammonium or cellulose nitrate solutions.