GB390530A - Improvements in the spinning of artificial fibres by dry methods - Google Patents

Abstract

Artificial filaments, yarns, threads, straws, tapes, ribbons, or like products are obtained by extrusion into a co-current of evaporative medium which is constrained by means of hoods, plates, or like collecting or constraining devices surrounding the spinning nozzle to flow in the same direction as the filaments, past and through the immediate vicinity of the nozzle. The constraining device may be of cylindrical, conical, or bell shape. The spinning cell itself may be of such shape as to constitute a constraining device surrounding the nozzle. The whole or a definite proportion of the evaporative medium may be constrained to pass through the vicinity of the nozzle, and the evaporative medium may be introduced into the cell in the vicinity of the nozzle. Apparatus similar to that described in the parent Specifications may be employed provided that the inlet and outlet for the evaporative medium are interchanged. The quantity of evaporative medium passing through the cell may be controlled by valves. The spinning solution and the evaporative medium may be heated, and the collector devices provided with heating means. The spinning jet may be of the disc, ring, or line type; it may take the form of a trough-shaped annulus with arrangements for air flow through the centre of the annulus. The process may be applied to the spinning of cellulose acetate or other cellulose ester or of ethyl cellulose or other cellulose ether. As shown in Fig. 1, filaments 14 are extruded from a nozzle 13 and passed downwardly through the spinning cell 10. A current of evaporative medium is introduced into the upper part of the cell from a <PICT:0390530/IV/1> <PICT:0390530/IV/2> <PICT:0390530/IV/3> <PICT:0390530/IV/4> <PICT:0390530/IV/5> <PICT:0390530/IV/6> <PICT:0390530/IV/7> <PICT:0390530/IV/8> perforated annular pipe 24 and passed downwardly through the cell to a draw-off pipe situated at the bottom. A tube 36 fitting in a diaphragm 37 constrains the evaporative medium to flow past and through the immediate vicinity of the nozzle. The cell is heated by pipes 34 through which steam, hot water, or other medium is caused to flow. Fig. 2 shows a ring jet 40 in the form of an annular trough 41 clamped to a member 42, the filaments being extruded from a ring of orifices at the bottom of the trough 41. The jet is surrounded by a collector device 43 in the form of a double cone. Figs. 3 and 4 show a line jet 45 and a slotted diaphragm 48 which causes evaporative medium to pass in the neighbourhood of the jet. The whole of the air current may be introduced through the pipe 46, or if desired some of it may be introduced through pipe 49. As shown in Fig. 5, a proportion of the downward current is constrained by the cone 52 to pass in the vicinity of the nozzle, but some of it passes down the cell through the spaces between the arms of the supporting bracket 53. Fig. 6 shows a spinning cell with a narrow neck 57 which constitutes the device for constraining the evaporative medium to pass in the vicinity of the nozzle. As shown in Fig. 7, the spinning solution is passed through a heating bath and after leaving the bath is insulated until it reaches the nozzle 13. The spinning nozzle 13 is situated within a cowl 65 to which evaporative medium is supplied by means of a flexible supply pipe 66. Fig. 8 shows a cylindrical cowl 70 surrounding the nozzle and provided with a heating coil 71. Specification 203,092, [Class 2 (ii), Cellulose &c.], is referred to.