GB719853A - Improvements in or relating to the production of artificial fibres - Google Patents

Abstract

<PICT:0719853/IV (a)/1> <PICT:0719853/IV (a)/2> Artificial filaments are produced from fusible filament-forming material, preferably in powdered form, by urging the solid material against one side of a plate having one or more spinning orifices and heated by passing an electric current through it, so that the material is fused on the surface of the plate, drawing the fused material away through the orifices and continuously supplying fresh solid material to the plate. The filament-forming material may be a cellulose ester such as cellulose acetate, propionate, acetopropionate or acetobutyrate, a cellulose ether, such as ethyl or benzyl cellulose, or a polymer such as polyethylene, polystyrene, polyhexamethylene-heptamethylene urea, a 4.4-polyurethane obtained from tetramethylene diamine and the dichloroformic ester of 1.4 butanediol, or mixtures of substances such as 50 per cent. cellulose acetate and 50 per cent. polyhexamethylene adipamide, or 90 per cent. cellulose acetate and 10 per cent. cellulose propionate. These materials are preferably supplied in the form of a powder the particle size of which is of the same order as the diameter of the spinning orifices, e.g. 0.025 inch. The powdered material may be urged against the heated plate by means of a tamper or by rotating vanes. As shown in Fig. 2, the jet plate 35 with orifices 41 is secured between two heat-resisting electrically insulating slabs 36, 37 and is supplied with electric current from a low-voltage source by heavy copper leads 42. Powdered material contained in the bin 50 is urged against the heated plate by a tamper 29 operating in a well 38 in the upper slab 36. The tamper is connected to the rod 21 by a slot and pin assembly 25, 26 so that if material is supplied to the well faster than it is being drawn away from the plate and the well becomes full of powder, the tamper will no longer be raised by the rod 21 which is actuated from a motor through an eccentric, and thus material is supplied substantially at the rate at which it is being used. The tamper may be in the form of a long bar, and a number of such units may be arranged in line and their rods 21 driven from a common shaft. In the arrangement shown in Fig. 6 the plate 35 with orifices 41 is again clamped between slabs 114, 115 and supplied with electric current through leads 42, but the powdered material from container 122 is urged against the plate by vanes 129 on a member 126, which rotates in the well 125. The shaft 127 is driven from the main shaft 132 through a slot and pin connection 133, 134 which permits the shaft 127 to rise if powdered material collects above the plate, and when this occurs the cone 130 on shaft 127 rises and cuts off the supply of powdered material from the container 122. The filaments produced may be drawn away from the orifices under their own weight or by a draw roller, and any desired reduction in denier may then be obtained.