GB976336A - Wet spinning artificial filaments - Google Patents

Abstract

976,336. Wet spinning artificial filaments. CELANESE CORPORATION OF AMERICA. March 15, 1961 [March 21, 1960], No. 9427/61. Heading B5B. In the production of artificial filaments, particularly cellulose triacetate filaments, by extruding a solution of a filament-forming material through a multiholed spinneret into a liquid coagulant having a swelling effect on the material and stretching the filaments formed during their passage through the coagulant, there is applied to the bundle of filaments leaving the coagulant a tension which is continuously or from time to time measured and maintained within a range predetermined to yield a product having a " tensile factor " approximately or actually the maximum possible under the spinning conditions. The " tensile factor " is defined as the product of the tenacity in grams per denier and the square root of the percentage elongation at break. The spinneret may have more than 1000 orifices and the tension applied to the bundle of filaments leaving the coagulant may be maintained within the range of 160 to 300 milligrams per filament. Before applying the tension the proportion of adherent coagulant carried by the filaments may be reduced to about 250% of the weight of the filaments, e.g. by friction applied by a member controlling the tension, or more coagulant may thereafter be squeezed from the filament by means of pairs of squeeze rolls to further reduce the proportion carried by them to between 100 and 200% by weight of the filaments. Coagulant may thereafter be evaporated from the filaments while they are in a tensionless condition. As shown in Fig. 1, the spinning solution is extruded through the spinneret 12 in the spin pot 11 into coagulant supplied to spin pot 11 through a sparger 14 supporting glass balls 16 which smooth out the flow of coagulant. From the spin pot the freshly formed filaments 17 and coagulant travel up the spinning column 18 and spent coagulant overflows into the head-box 19 from which it drains away through outlet 20. The filament bundle 17 passes first over a saddle guide 21 (Figs. 1 and 2), then over pins 22 to 24 and a tensiometer 25. The filament bundle 17, along with one or more similar bundles 26 from adjacent spinning positions, then passes successively between squeeze roll pairs 27-28, 29-30, 31-32 and 33-34. The filament tow leaving the roll pair 33-34 passes through air jet 35 where it is opened and partially dried and then passes through oven 36 where drying is completed in tensionless state. Finally the filaments are cut into staple fibre 38 by centrifugal cutter 37. Pins 22 to 24 and saddle guide 21 are adjustably mounted in the slots 40 of a plate 41 hinged at 42 to the wall of head-box 19 and held by spring clip 43. Specification 881,856 is referred to.