METHOD AND DEVICE FOR PREPARING FIBRES FROM POLYMER SOLUTIONS

摘要

1409530 Spinning fibres CESKOSLOVENSKA AKADEMIE VED 20 Dec 1972 [22 Dec 1971] 58731/72 Heading B5B A solution 1 of a polymer is extruded through a spinneret 2 into a spinning shaft 4, inside which the gas 6 is at a lower pressure than the external atmospheric pressure, the lower end of the shaft being placed in a bath 5 of coagulation liquid so that the liquid rises inside the lower part of the shaft 6. The gas is advantageously preheated and circulates through the shaft via an inlet 8 and an outlet 9. The liquid level is maintained at constant height in the shaft by placing the mouth of the pipe 7. leading to a vacuum pump, at the desired height, the valve (12), Fig. 2 (not shown), opening and closing according to the liquid level. Any liquid passing the valve is separated from the gas stream and returned to the coagulation bath. Solvent vapour is separated from the gas stream by condensation, Fig. 3 (not shown), or adsorption on charcoal. The gas 6 in the shaft may be heated to a higher temperature than the liquid in the lower part of the shaft, which may in turn be cooled to a lower temperature than the rest of the coagulation liquid. This may be done by heating and cooling jackets, or infra-red heating. The shaft may be square, circular or elliptical in cross-section. The spun fibre is drawn off via roller 10. The apparatus may be used for spinning bi-component fibres, using a split spinneret. The solution 1 may be polyacrylonitrile in ethylene carbonate, dimethyl formamide, 65% nitric acid, aqueous zinc chloride, or sodium thiocyanate, polyvinyl chloride in cyclohexanene, chlorinated P.V.C. in acetone-alcohol, cellulose triacetate in methylene chloride, cellulose acetobutyrate in acetone, or cellulose diacetate in acetone-alcohol.