Patent GB-1035831-A (GB)
Title: Production of multi-component artificial filaments and multi-component artificial yarns
IPC: D01D5/32
Filed: 1963-02-27
Abstract: 1,035,831. Making composite artificial filaments and yarns. CELANESE CORPORATION OF AMERICA. Feb. 27, 1963 [March 7, 1962], No. 7848/03. Heading B5B. In spinning multi-component filamentary material by extruding different filament-forming liquids under pressure, the liquids, each under constant pressure are fed to one or more spinnerets in a single stream from a junction where they meet in a conduit in which they are maintained in laminar flow to prevent them from mixing. As illustrated in Fig. 1 (not shown), an apparatus 10 for producing a threecomponent filament or yarn comprises three separate low-pressure drop chambers or headers 12, 14 and 16 from which separate conduits 18, 20 and 22 lead to a common juncture point 24 to form a common conduit 26, which ultimately feeds a filament-forming spinneret 28. Between the junction 24 and the spinneret 28 are disposed a throttle valve 30 and a two-way valve 32. A second spinneret 34 communicates with two-way valve 32 through conduit 36. Filament-forming liquids A, B and C are introduced at constant predetermined flow rates into chambers 12, 14 and 16 by metering pumps 38, 40 and 42 respectively. The liquids are maintained at constant pressures within the chambers by means of the surge tanks 44, 46 and 48 which are fitted with spring-loaded pistons 50, 52 and 54 and communicate with the chambers 12, 14 and 16 by means of ducts 56, 58 and 59 respectively. When all three chambers are to be maintained at the same pressure a single surge tank communicating with the three chambers may be employed. The surge tank or tanks may be provided with weighted pistons or a constant head tank may be used to maintain the pressure constant. In the operation of the apparatus the magnitude of the constant pressure in each header is so adjusted, having regard to the cross-section and length of the conduit leading from each chamber, that the flow of the liquid stream flowing through each conduit is laminar or of streamline character and not turbulent. If a multi-component or conjugate filament is desired, the common stream is fed through a spinneret 28 having a single orifice. On the other hand, in order to obtain a multi-component yarn or bundle of filaments from a single spinneret, a spinneret 60 (Fig. 6, not shown) having a number of orifices 70 is substituted for the spinneret 28 and the common stream is fed therethrough so that the liquids A, B and C pass through the orifices in the corresponding zones A, B and C respectively. All the filaments thus formed are collected together thereby forming a three-component yarn. The denier of the multicomponent filament or multi-component yarn is controlled by adjustment of the throttle valve 30. A number of conduits may communicate with each of the chambers 12, 14 and 16 so that a corresponding number of spinnerets 28 or 60 may each be supplied with the liquids A, B and C. In order that the pressures in the chambers may remain unaltered when the spinnerets 28 or 60 are substituted by another spinneret, the two-way valve 32 is turned so that the common stream of spinning liquids is temporarily diverted to the dummy spinneret 34 which offers resistance to the flow of the common stream equal to that offered by spinnerets 28 or 60. The relative proportions of the components in the multi-component filament or yarn are controlled by adjustment of the relative pumping rates of the metering pumps 38, 40 and 42. As illustrated in Fig. 5 (not shown) filament-forming liquid A is introduced into conduit 62 by metering pump 64 and filamentforming liquid B is introduced through conduit 66 into the centre of the stream of liquid A by metering pump 68. The rate of introducing the liquids is controlled to be sufficiently low to ensure that their flow is non-turbulent so that liquid A forms a sheath stream about the core stream of liquid B. The common sheath and core stream is fed through filters 61 to spinneret 60 (Figs. 5 and 6, not shown). The core stream extrudes from that portion of each orifice 70 nearest the centre of the spinneret and the sheath stream from the remaining portion of each orifice. The apparatus illustrated in Fig. 5 (not shown) may be modified so that the liquid flowing through the conduit 62 consists of a core stream and two or more concentric sheath streams.