Patent GB-370017-A (GB)
Title: Improvements in or relating to the production of artificial textile materials
IPC: D01F2/28
Filed: 1931-01-01
Abstract: <PICT:0370017/IV/1> <PICT:0370017/IV/2> <PICT:0370017/IV/3> <PICT:0370017/IV/4> Artificial filaments, yarns, or threads ar reduced in denier to a regular or irregular extent at regular or irregular intervals along their length, by treatment with a softening agent or otherwise bringing into a softened condition, for example, as by heating, and then applying stretch thereto. The products obtained are similar to those made according to the process of Specification 321,762, [Class 2 (ii), Cellulose &c.], in which reduction in denier at intervals is effected during the manufacture of the filaments &c. The softening agent may be applied to the whole length of the filaments which are then subjected to an intermittent stretching force in the manner described in the prior case; or the filaments may be softened at intervals and then subjected to a continuous stretching force or to an intermittent stretching force which may or may not coincide in phase with the softened portions of the filaments. The intermittent softening may be obtained either by the intermittent application of the softening medium as by intermittently immersing a length of the filaments in a bath of the softening liquid, or alternatively by protecting certain portions of the filaments by the application of resists or reserves or by means of protective clips, these latter methods being preferred if short spacings are desired. The means for applying the softening medium may comprise reciprocating or oscillating members actuated by cams, cranks, eccentrics, &c., or the filaments may be similarly displaced so as to make contact with wicks, pads, etc.; or rotary members with arms regularly or irregularly disposed and regularly or irregularly driven may be similarly employed both for the application of softening medium and also reserves or resists; or these may be applied by splashing. In all cases the actuating means may operate in a regular or irregular manner.  Softening and stretching may be continuous operations, or the filaments may first be softened and then carried through the stretching apparatus.  For filaments of cellulose acetate and other cellulose derivatives, suitable softening agents are aqueous acetone, aqueous dioxane, and acetic acid; and the softening action may be assisted by heat as by the use of glycerine heated to 160 DEG  C. With regenerated cellulose filaments, Schweitzer's reagent, zinc chloride solution, and sulphuric acid are suitable softening agents.  Suitable reserves or resists are mineral oil with acetone or dioxane, paraffin wax with acetic acid, and varnishes with glycerine.  The filaments to be treated may be of regular denier, or they may be irregular filaments such as are produced in the process of Specification 321,762 above referred to, and in such cases the further drawingdown may follow as a continuous p  operation and it may be arranged to take place at the points of reduced denier so as to enhance the effect.  The filaments to be treated may contain substances adapted to facilitate softening or stretching of the filaments, for instance, cellulose acetate &c. filaments may have a content of plasticizers.  The filaments of variable denier may be twisted into threads having low, medium, or high twist, and they may be combined with other filaments, yarns, etc.; and they may be combined with other filaments of the same varying denier in such a manner that the variations are coincident. The residues of softening agent may be removed by washing or by evaporation in which case the filament may be allowed an extended air-run. As shown, filaments 5, Fig. 1, from a spinning cell 6 or some other source are passed under guides 9, 10 depending in a bath 12 of softening liquid and then round rollers 13, 14 between which is a reciprocating member 17 actuated by a cam 19 so as intermittently to stretch the thread, the slack produced by the stretching being taken up by the increased peripheral speed of the second roller 14. In order to reduce the consumption of softening liquid, the guides 9, 10 may be intermittently raised as by a cam 22.  In another form the thread 23, Fig. 2, is intermittently withdrawn from contact with a wick 26 carrying the softening liquid by means of a rotating member 28 having arms 29 for engaging the thread, and the thread is then passed round rollers 25, 30 the second of which has a higher peripheral speed so as to stretch the softened portions of the thread.  In a further form particularly applicable for the treatment of a large number of threads 45, Fig. 4, drops of softening liquid are projected irregularly on to the threads by means of a rotating brush 48 supplied with liquid from a tank 49 and moving in contact with a blade 50; the threads pass on to pairs of stretching rollers 47, 52.  In Fig. 3 is illustrated the manner of applying a resist to threads 32 proceeding from a spinning cell 33 to a device for intermittently stretching the threads, comprising a pair of guides 34, 35 oscillated by a crank 38, and thereafter under a rotating arm 42 which depresses the threads on to a wick carrying a resist.  The threads after being wound on a bobbin 41 are treated according to the method described above.