GB651980A - Improved process and device for the continuous manufacture of artificial threads - Google Patents

Abstract

<PICT:0651980/IV (a)/1> Artificial threads are produced and subjected to a succession of treatments with liquids in a continuous manner; in each of the wet treatments, the freshly formed, untwisted thread is led upwardly in a substantially vertical path and is wetted, on this upward path, in a region where the thread is free from contact with any guide or supporting member, with a treatment liquid which is directed on to the thread at the upper portion of said path against the direction of movement of the thread and which in its fall forms a liquid-cylinder surrounding the ascending thread. After the thread has left the primary coagulation bath, it may be led in a number of ascending and descending lengths, the substantially vertically ascending portions being treated with the liquids necessary for after-treatment. The process is particularly suitable for the production of threads from viscose or cuprammonium cellulose solutions and the treatments may include further coagulation, neutralizing, removal of copper, desulphurizing and bleaching. The wetting vessel or other device from which the treatment liquid is applied to the thread should be arranged so that it is not touched by the thread. If desired, the thread may proceed continuously from the after-treatment devices to a drying device and may then be wound on bobbins or other collecting devices. Alternatively the wet-treated thread may be collected in cake or bobbin form and then dried and processed further in such form. Stretching may be effected before or between the various wet treatments, or during the drying. After the thread has been dried, it may be wound and twisted on a ring-twisting bobbin. This may be rotated at a peripheral speed about that of spinning, so as to facilitate threading-up, and then at a higher speed to give the thread the required twist. As shown in Fig. 1, a thread 4 of artificial filaments from spinneret 1 emerges from coagulating bath 26 and passes substantially vertically upwards to pulley 5 round which it passes several times, the various turns being separated by means of inclined guide-pulley 6. The thread then passes downwardly into tank 27, round guide-roller 7, and vertically upwards to pulley 10. At the p upper part of the upward path of the thread, the latter is bathed with liquid from the device 30 which is adjusted so that its nozzle surrounds the thread without touching it. The liquid descends along the upwardly-moving thread and is collected in tank 27. The thread passes from pulley 10 to tank 28. It then continues its ascending and descending paths and is successively treated with different liquids from devices 31-34. The thread then passes several times between the heated metal conical roller 19 and guide roller 18 until it is dried. The form of the roller 19 allows for shrinking during drying. The spacing of the windings of the thread on pulleys 5-13 and on roller 19 may be varied by adjusting the inclination of rollers 6 and 18. The dry thread is then wound on a ring twisting device driven by motor 25. The motor may be operated at two speeds, one for threading-up, and the other for effecting twisting with winding. A centrifugally-operated slip clutch 23 to facilitate threading-up is provided. In an example, viscose is extruded into sulphuric acid solution containing zinc and sodium sulphates. The preliminarily coagulated thread obtained is stretched between pulleys 5 and 10 and treated with warm dilute sulphuric acid from the device 30. The regenerated cellulose thread is then washed with hot water from pipe 31 and with sodium sulphide from pipe 32. It is washed with hot water from pipe 33, and then treated with an emulsion containing 2 per cent of a partially saponified fat. The thread is then dried on drum 19 heated to 125 DEG C., and wound and twisted. If desired, the upward direction of the thread during the wet treatments may deviate very slightly from the truly vertical but it should not deviate more than 5 degrees. Where mixing of two treatment liquids is admissible, two treatments may be effected in a single ascending path of the thread. In another example, a viscose rayon thread consisting of a large number of elementary filaments, and suitable for making a tyre cord, is produced and submitted in continuous manner to fixing, desulphurizing, washing, and sizing treatments. Specification 584,070 is referred to.