GB744319A - Improvements in the spinning of artificial filamentary materials - Google Patents

Abstract

<PICT:0744319/IV(a)/1> <PICT:0744319/IV(a)/2> An apparatus for wetspinning filamentary materials comprises a spinning chamber into which coagulating liquid is supplied and in which is fixed an upwardly facing spinning head, incapable of movement during spinning, carrying a multi - orifice spinning jet, and a smooth-walled spinning tube extending upwardly from the chamber through which the filament bundle and coagulating liquid leave the spinning chamber and the diameter of which nowhere exceeds the diameter of the filament bundle by more than one inch at the same level. As shown in Fig. 2, the spinning chamber comprises a cylinder 12 and a cover 13, a spinning head 23 supplied with spinning solution through a conduit 17 being mounted therein. A multi-orifice jet 20 is attached to the spinning head by a fitting 24 which also clamps in place a filter unit 19. Coagulating liquid is supplied through a conduit 25 to a distributing chamber formed between the spinning chamber and a plate 27 extending between the head 23 and cylinder 12. The distributing chamber comprises also a plate 28 carried by a collar 29 attached to the conduit 17 and extending to near the wall of the cylinder 12, the plate 28 being separated from the plate 27 by a cylindrical coaxial tube 31. The coagulating liquid enters the spinning chamber through apertures 32 in the tube 31 and apertures 33 provided in the plate 27 concentric with the cylinder 12. The spinning tube 37 extends through a gasket 38 in the cover 13 and abuts an extension tube 35, between which and the spinning jet 20 extends a cylindrical foraminiferous screen 34. The tube 37 has two cylindrical portions 41, 43 connected by a tapered portion 42, the upper cylindrical portion 43 extending into a cylindrical chamber 45 into which a further supply of coagulating liquid is admitted and from which the filament bundle 22 and coagulating liquid leave through a cylindrical tube 49. The coagulating liquid is supplied to the chamber 45 through a conduit 46 and an annular chamber 47 partitioned into two portions connected by apertures 48, the lower portion having apertures 481 communicating with the chamber 45. The diameter of the tubes 37 and 49 may at no point exceed the diameter of the filament bundle by more than half an inch. The minimum diameter of the tapered tube 42 may be from 0.5 to 0.84 times the maximum diameter of the tube. The diameter of the jet face in inches may be equal to that of the adjacent tube end and may lie between the limits 0.25+(N/186\sB 0.5) 1/2 , where N is the number of orifices in the jet. The flow of coagulating liquid through the tube 37, expressed in cubic centimetres per minute, may be from 2N to 4N, subject to a minimum of 372(d - 0.25)2, where d is the largest diameter of the tube 37. The spinning solution may be a solution of cellulose acetate, cellulose butyrate, cellulose propionate, cellulose acetatepropionate or cellulose acetate-butyrate in acetone/water mixtures, diacetone alcohol, nitromethane, acetic acid, methyl acetate or methyl ethyl ketone, or methylene chloride or ethylene chloride alone or in admixture with alcohol. The coagulating liquid may be aqueous or non-aqueous and may contain acetone, diacetone alcohol, acetic acid, formic acid, ethyl lactate, zinc chloride, sodium thiocyanate, methylene chloride, ethylene chloride or a mixture of methylene and ethylene chlorides. The spun yarns may be saponified in known manner. Specifications 709,599 and 728,778 are referred to.