GB787563A - Improvements in or relating to the production and treatment of artificial and other filamentary materials - Google Patents

Abstract

<PICT:0787563/IV (a)/1> In a process in which filamentary material passes up and out of a substantially vertical tube up which liquid is also flowing, the material, after it has left the tube and before it makes contact with any other object, is caused to pass in an arc of a circle over and in contact with a rotating stripping roller; the arc may be of 5-90 degrees and especially 10-70 degrees. Adherent liquid is thereby removed from the material. The stripping roller may be positively driven or it may be freely mounted and caused to rotate by the friction of the filamentary material passing in contact with it. Its peripheral speed preferably does not exceed the rate of travel of the filamentary material and may with advantage be slightly or even considerably lower. Thus the peripheral speed of the roller may be about 60-98 per cent of the rate of travel of the filaments, the lower roller speeds being preferred for filamentary material of denier over about 500, such as tow. A freely mounted roller may be braked in order to maintain its peripheral speed below the rate of travel of the material. As shown in relation to a wet-spinning apparatus, spinning solution is pumped through the feed-pipe 12 to the spinning jet 11 mounted axially in the extrusion chamber 6 directly below and about 2-3 inches from the flared lower end of the lower section 8 of the setting tube 7. A coagulating liquid is fed through the inlets 13 into the chamber 6 and flows through the gauze 14, which eliminates turbulence, past the jet 11, and into and up the setting tube 7, at the top of which it overflows through the orifice 10 into the colector head 15, which it leaves by the run-off 16. The filaments so formed travel up the setting tube 7, in which they are coagulated, and from the orifice 10 at the upper end of the setting tube they pass, now in the form of a yarn 21, over the stripping roller 2 to the godet 3 with an associated skew idler roller 4, by means of which they are drawn out of the setting tube. As the yarn passes over the stripping roller 2 much of the coagulating liquid carried by it is transferred from the yarn to the roller, from which it falls off on to the inclined upper section 19 of the guide member 18 carried by a supporting fin 17. The liquid then flows down the guide member until it enters the collector head 16. The godet 3 runs at such a rate that the filaments are stretched before they are fully set. From the godet the yarn passes in a zig-zag path over and under alternate members of the set of friction fingers 5, where it loses more coagulating liquid. The stripping roller 2 may be a smooth cylindrical phosphor-bronze roller provided with driving means (not shown), by means of which it can be driven at a peripheral speed from 60 to 100 per cent that of the godet 3, or a light freely running roller, which may be braked. The relative positions of the axis of the setting tube 7, the stripping roller 2 and the godet 3 are such that the yarn passing from the orifice 10 to the godet 3 contacts the stripping roller over an arc of about 45-50 degrees. The method may be applied in wet-spinning processes in which a cellulose acetate filamentary material is set by a coagulant comprising aqueous diethylene glycol diacetate, or in which an acetone solution of cellulose acetate is extruded into aqueous acetone or an acetic acid solution of cellulose acetate is extruded into aqueous acetic acid containing a high concentration of an alkali-metal acetate. Specifications 695,559, 720,187, 736,636, 787,556, 787,557, 787,558, 787,560, 787,561 and 787,562 are referred to.