Patent GB-375424-A (GB)
Title: Improvements in the production of artificial threads, ribbons and like materials
IPC: D01F2/28
Filed: 1931-03-27
Abstract: <PICT:0375424/IV/1> <PICT:0375424/IV/2> <PICT:0375424/IV/3> In the production or treatment of artificial filaments, threads, ribbons, films, and similar materials containing organic derivatives of cellulose, the materials are stretched while in a plastic state by drawing them through a body of liquid moving so as to exert a drag upon them.  The cellulose derivative may be an acetate, formate, propionate, butyrate, nitro-acetate, or other ester, or a methyl, ethyl, benzyl, or other ether, or a mixed ether, or an ether-ester. The spinning solution may contain high-boiling solvents and plasticizers.  It is preferable to effect coagulation in such manner that the filaments emerge in a more or less plastic state.  The coagulating medium may contain solvents or swelling agents. Paraffin, petroleum, toluene, nitrobenzene, hexachlorethane, castor oil, sesame oil, or olein may be employed as coagulating medium as an alternative to an aqueous medium.  When the movement of the coagulating bath produces the desired drag, the effect may be increased by the use of substances of high viscosity such as sulphuric acid, sulphuric esters, sulphonated compounds, starch, sulphite cellulose waste lye, sucrose, molasses, glucose, lactose, mannitol, dulcitol, and glycerol.  It is preferable to extrude the spinning solution into a zone of liquid which is stationary or nearly so, the filaments passing to a region where the liquid flows in counter-current. The direction and velocity of the liquid may be controlled by the shape of the containing vessel, or by the provision of baffles, or channels, or by introducing or removing liquid at various points in the path of the filaments.  The spinning vessel may be in the form of a Y, extrusion of the filaments taking place in one limb where the coagulant is at rest or moving in the direction of extrusion, and a counter-current of liquid flowing through the other two limbs.  If desired separate vessels for extrusion and treatment with the counter-current of liquid may be employed. The counter-flow may be produced by the use of sufficient head of liquid, by pumps, injectors, or ejectors, and some of the liquid may be continuously circulated.  If desired the counter-current may be set in operation only after the commencement of spinning. Filaments of varying denier may be obtained by intermittently varying the velocity of flow of the coagulant.  The process is also applicable to filaments and other materials obtained by dry spinning processes, and also to fully formed materials.  In the latter case, the materials are treated with a swelling agent and this treatment may be carried out continuously with the stretching process.  The swelling or softening agent may be acetone or other ketone, butyl acetate, ethyl lactate, diethyl tartrate, ethers and esters of glycols, dioxane, dibutyl tartrate, diacetone alcohol, phenol, thiocyanates, or zinc chloride.  At least part of the tension required to draw the filaments through the counter-current of liquid may be applied by means of a liquid flowing in the direction of travel of the filaments.  The process may be associated with processes of delustring, metallizing, dyeing, sizing, weighting, and saponifying, and with processes for producing hollow filaments.  As shown in Fig. 4, filaments 12 extruded from nozzle 11 are drawn upwardly through a counter-current of coagulating medium in the vessel 10.  Liquid enters through pipe 14 and through an injector device 23.  The main body of liquid passes down funnel 13 and finally out through pipe 15 which is constructed as an ejector which induces a flow of liquid through the cone 17 and pipe 20.  A baffle-plate 21 prevents a turbulent flow in the cone 17.  As shown in Fig. 8, threads are unwound from a bobbin 27 and passed upwardly through the opening 15 in the vessel 10.  Liquid enters through pipe 14 and issues through the opening 15.  The threads are brought to a plastic condition either by the stretching liquid or by treatment with a softening liquid prior to their entry into the vessel 10. As shown in Fig. 9, filaments 36 issue from a dry spinning cell 35, pass round the roller 37 and round another roller 28 where they are sprayed with softening liquid.  They are then passed through a tube 31, where they meet a counter-current of liquid, round a draw roller 33 sprayed with washing liquid, and on to a collecting device.  Specifications 177,868, 179,234, 318,467, 326,777, 334,838, 334,853, 338,490, [all in Class 2 (ii), Cellulose &c.], 340,324, 340,325, 340,436, 341,148, 341,388, 341,897, 343,062, 343,949, 346,678, 346,793, and 371,343 are referred to.