GB613164A - Improvements in or relating to the production of artificial filaments - Google Patents

Abstract

<PICT:0613164/IV(a)/1> Artificial filamentary materials are obtained by extruding a solution of a filament-forming material in a volatile solvent through a spinning jet into a spinning chamber, setting the filaments in a mist of droplets of an extractant liquid which dissolves the volatile solvent, and removing volatile solvent from the spinning chamber through an opening in the vicinity of the spinning jet by suction produced by a jet of aspirating liquid which is a solvent for and absorbs the volatile solvent. Most of the solvent and extractant liquid are dissolved by the jet and removed, while the air may be returned to the spinning chamber in the vicinity of the spray device through which the mist of droplets is introduced. Spinning speeds of more than 300 metres per minute may be attained. The filament-forming material may be cellulose acetate dissolved in acetone, and the filaments may be extruded into a mist of water droplets. The acetone vapours may be removed by an aspirating jet formed by a stream of water forced through a nozzle under pressure. The spinning solution, the water to be sprayed into the chamber, and the water forming the aspirating jet, may all be heated. Instead of acetone, there may be used ethyl ether-alcohol mixtures, di-chlor-methane, or carbon disulphide, as the volatile solvent, and instead of water there may be used methanol or hexane as the liquid for the mist and aspirating jet. Other cellulose esters or ethers may be used instead of cellulose acetate. As shown in Fig. 1, artificial filaments are obtained by extrusion of spinning-solution from nozzle 10 in the closed spinning chamber 4. The filaments 11 leave the chamber through orifice 18. Spray nozzles 13 form a mist of water or other extractant liquid and the falling spray p collects in a well 16. A tapered neck 17 prevents liquid from falling through the orifice. Solvent-laden air is aspirated from the top of the chamber through pipe 25 by means of a jet 27 which discharges water or other liquid under pressure through a constriction into pipe 29. To enable the pressure in chamber 4 to be adjusted, a pipe 30 with valve 31 connects pipe 29 to the lower end of the chamber. Liquid from pipe 29 is removed through valve 32. Specification 581,354 is referred to.