Patent GB-378074-A (GB)
Title: Improvements in the treatment of artificial filaments and the like
IPC: D01F2/28
Filed: 1931-05-06
Abstract: <PICT:0378074/IV/1> <PICT:0378074/IV/2> <PICT:0378074/IV/3> A liquid having a solvent, softening, or swelling action is applied to artificial threads, yarns, ribbons, and like filamentary materials which are submitted to stretching in such manner that the stretching force is applied at points where there is little or no weakening of the materials.  The softening liquid is preferably applied and removed between the points where the stretching force is applied.  If desired the filaments may be stretched in a number of stages either continuously or with intermediate rewinding.  The invention is applicable to materials of cellulose acetate, or nitrate, or other cellulose ester, or of ethyl, benzyl, or other ether of cellulose, or of regenerated cellulose from viscose, nitrocellulose, cuprammonium, or other cellulose solutions.  The softening agent may be applied diluted with water, alcohols, hydrocarbons, or ethers, and then concentrated by heat or air current.  The softening effect is enhanced by the application of heat.  Removal of the softening agent is effected by evaporation or washing.  As shown in Fig. 1, filaments 10 from a dry spinning machine 11 pass round a stretching roller 12 which dips into a trough 13 containing softening liquid.  The roller 12 may rotate faster than the speed of extrusion so as to stretch the filaments.  The filaments then pass over roller 15 dipping in washing liquid to a second stretching roller 16 round which they are wrapped and from which they pass to a cap-spinning device 18.  If desired the filaments may be wrapped round roller 15 which then acts as a stretching roller and roller 16 may be dispensed with.  In this case, the nature of the washing liquid must be such that the filaments lose their softened state before coming into full contact with the roller. As shown in Fig. 2, threads 21 are drawn from bobbins 22 over and under tension bars 24 through a reed 25 to a roller 26, provided with nip-rollers 27, and dipping into a slowly acting softening liquid 14. The threads pass to rollers 28, 29 rotating faster than rollers 26, 27, the softening liquid being removed by the light contact of roller 15 which dips into washing liquid 20. The threads are then drawn over a drying plate 30 and pass to bobbins 34.  If desired roller 26 may be provided with three nip-rollers in which case the threads need pass only round the upper part of roller 26.  When using a softening liquid with rapid action, it is preferable to apply it after the threads have left the first stretching device and it may be applied by sprinkling or by a moistened roller.  As shown in Fig. 5, warp threads 47 from a beam 48 pass through a reed 49 and between nip rollers 12 which act as the first stretching device.  They pass over a roller 44 moistened with softening liquid which is removed by a heavy spray of washing liquid 50 as they reach the stretching roller 16.  As shown in Fig. 6, the filaments are washed before they reach the second stretching roller 16 by a stream of water or other liquid in a trough 57.  After the first stretching, the filaments may be stretched in a similar manner in further stages between which there may be rest periods which may be provided by passing the filaments in looped paths round faller rollers.  Specifications 277,089, 323,790, [both in Class 2 (ii), Cellulose &c.], and 359,971 are referred to.