Patent GB-1393351-A (GB)
Title: Method for producing mixed filaments
IPC: D01F8/04
Filed: 1973-02-15
Abstract: 1393351 Mixed filaments; fibrillation KANEBO KK 15 Feb 1973 [24 Feb 1972] 7527/73 Heading B5B [Also in Division D1] Mixed filaments are made by simultaneously spinning a polyester and a polyamide through a common spinneret to give mixed filaments comprising (a) polyester/polyamide multi-segment filaments, in each of which the polyester is divided by the polyamide into at least 3 segments, and (b) single component polyester filaments, the mixed filaments satisfying the following requirements: (i) the multi-segment filaments form from 40 to 70% by weight of the total weight of the mixed filaments; (ii) the polyamide content of each of the multi-segment filaments is less than 30% by weight; (iii) the polyamide forms radially divergent thin layers of even thickness, as viewed in cross-section of the multi-segment filaments, and (iv) a polyester segment in the multi-segment filament has a denier of less than 1 and the single component polyester filament has a denier of more than 2; drawing the spun mixed filaments; and then false twisting the drawn mixed filsments to fibrillate the multi-segment filaments. Preferably the polyamide content of the multisegments and the polyamide content of the multi-segment filaments is less than 25% by weight. The multi-segment filaments may contain 3 to 8 polyester segments, especially 3 to 6, and may have the cross-section shown in any one of Figs. 1-5. (Figs. 1 and 2, only are shown). The polyester segment in the multi-segment filament may have a denier of less than 0À7 and the single component polyester filament may have a denier of 3 to 10. The preferred polyester is polyethylene terephthalate and preferred polyamides are hexamethylene adipamide and e-polycaproamide. The mixed filaments may be spun using the spinneret of Fig. 6. A part of the molten polyester is extruded from inner orifices 5 through supply chamber 2 and passage 3 and the molten polyamide is extruded from channels 8 through a supply chamber 1, passage 6 and reservoir 7. The two polymers are bonded together at the inlet of conduit 9 and spun from an orifice 111, through conduit 9. A part of the remaining polyester is spun from an orifice 111 through supply chamber 2, passage 4 and conduit 9, Figs. 7 and 8 (not reproduced), illustrate the internal construction of the spinneret. Mixed filaments are produced consisting of three multi-segment filaments in which the polyester is divided into four segments by four radially divergent thin layers of polyamide and three single component polyester filaments. On false twisting, the segments in the multisegment filaments are separated into fibrils and the single component polyester filaments and the fibrillated segments become entangled to form the mixed filaments. In an example the filaments are drawn to 3À6 times their original length on a draw pin at 105 C. and wound up while being contacted with a metal plate at 165 C. for about 0À1 sec. to give the drawn yarn which is then false twisted to induce fibrillation, fed through a metal tube heater at 215 C. and taken out at 60 m./min. through a spindle rotating at 200,000 r.p.m. and wound up at 55 m./min.