Patent GB-611136-A (GB)
Title: Production of slivers of artificial staple fibres
IPC: D01D5/26
Filed: 1946-04-23
Abstract: <PICT:0611136/IV(a)/1> <PICT:0611136/IV(a)/2> A sliver of artificial staple fibre in which the staple fibres overlap and are staggered longitudinally is formed by a process comprising the formation of a composite of filament-forming material and other material, both being in a flowable condition and being immiscible and retaining their separate identity, continuously feeding the said composite through a spinneret, the component parts of the mixture being so disposed uniformly throughout the composite so as to present bodies of each material to the individual orifices at frequent intervals, the bodies of the said other material filling the orifices to the temporary exclusion of the filament-forming material and after passage through the orifices separating said other material from the filament-forming material.  The process is equally applicable to wet-, dry-or melt-spinning.  For example, in the wet-spinning of viscose in which the viscose may be the dispersed phase of the composite, the continuous phase may be a light mineral oil or naphtha which will rise to the surface of the coagulating bath and be drawn off, or carbon disulphide which will collect at the bottom of the tank.  The composite is maintained in a tank 15, Fig. 1, provided with a stirrer 16 and is pumped to a spinneret 11 under the surface of a conventional coagulating medium 12 in a tank 13.  The coagulable particles of viscose 20 are shown in Fig. 2 approaching and passing through the extrusion orifices and being formed into filaments 20a. The non-coagulable liquid 21 is shown interrupting the flow of the viscose particles.  A similar situation obtains when the viscose forms the continuous phase and the other liquid is the dispersed phase.  The staple fibres formed are uneven in length.  To ensure a uniform action of the coagulating bath and to hold the fibres loosely together during coagulation they are confined laterally in a perforated tube 25 in the bath.  If the spinneret and tank are rotated relatively a twist is given to the sliver; to achieve this the tank may be p  mounted upon a turntable 27.  Fresh coagulating solution may be added through a pipe 30 and excess removed by the pipe 31.  The sliver is supported on a perforated diaphragm 32 so that it does not foul the open end of the pipe 31.  The process may be worked continuously, although as shown in Fig. 1, it is necessary to remove the sliver periodically from the tank.  Two disperse phases may be employed, for example, casein in aqueous sodium hydroxide and zein dissolved in ethyl alcohol and mixed with light coal-tar naphtha or a heavy chlorinated product in which both are insoluble.  In the dry-spinning of cellulose acetate, the solvent (acetone) may be allowed to evaporate and solidify the cellulose acetate, the other material being a waxy hydrocarbon which may be removed by a solvent. In the melt-spinning of nylon or "Vinyon" (Registered Trade Mark) the thermoplastic filament-forming substance may be allowed to solidify and the other material, which may be a plastic waxy hydrocarbon may be removed by a solvent.