GB787558A - Improvements in the production of artificial filamentary materials - Google Patents

Abstract

<PICT:0787558/IV (a)/1> In the wet-spinning of artifical filaments wherein the filaments are drawn from the spinneret through a narrow tube through which coagulating liquid flows, the filaments are drawn through and out of the tube by a godet which makes contact with the filaments at intervals along their length. The godet may comprise a fluted roller having flutes parallel to its axis, the flutes and lands being approximately equal in width and the edges of the lands being rounded off slightly. As shown, filaments are spun upwardly from the jet 2 in coagulating bath 1 supplied with coagulating liquid through pipe 4 and gauze 6, which prevents turbulence. Coagulating liquid passes up tube 7 and is collected in collector head 10, whilst excess liquid adhering to the filaments is removed by pigtail guide 13 and drains over inverted funnel 12 into the collector head 10, as described in Specification 787,556. The filaments are drawn out of the tube and stretched by fluted roller 14, which may be associated with a skew idler roller (not shown) which may or may not be fluted. The filaments are then passed round skew rollers 17 in washing bath 18. The invention is of particular value in the extrusion of acetone solutions of cellulose acetate into aqueous solutions of diethylene glycol diacetate or of aqueous acetone, but may be used in other wet-spinning processes, e.g. in the wet-spinning of acetic acid solutions of cellulose acetate, using as coagulant aqueous acetic acid containing a high concentration of a salt such as an alkali metal acetate. Specifications 720,187, 787,557, 787,559, 787,560 and 787,561 also are referred to.