Patent GB-1313767-A (GB)
Title: Synthetic complex conjugate filament and process of manufacturing the same
IPC: D01D5/30
Filed: 1970-03-24
Abstract: 1313767 Synthetic complex conjugate filaments TORAY INDUSTRIES Inc 24 March 1970 [26 March 1969] 14207/70 Heading B5B [Also in Divisions C3 and D1] A synthetic complex conjugate filament for use in the manufacture of a composite filament having crimp potential comprises a plurality of spaced composite filamentary segments extending along the filament length, each of said segments being composed of at least two filamentary components consisting of synthetic polymers differing from each other in shrinking property (which may be thermal shrinkage or solvent shrinkage) and disposed in an eccentric core-in-sheath type or side-by-side type filamentary form, and a synthetic polymeric filamentary bonding component bonding said composite filamentary segments into a filament body by filling up the spaces between said composite filamentary segments. In the case of the core-in-sheath structure, the core components in the composite filamentary segments may consist essentially of the same polymeric material as that of the bonding component and the sheath components may have a removal rate lower than that of the bonding component with respect to solvents effective for removing said bonding component; in the case of the side-by-side structure each of the filamentary components in the composite filamentary segments may have a removal rate lower than that of the bonding component with respect to the said solvents. With either corein-sheath or side-by-side type complex conjugate filaments, at least one of the filamentary components in the composite filamentary segment may be a polyamide, polyester, polyolefin or acrylic polymer; where polyesters are used, the materials of all of the filamentary components may comprise polyesters differing from each other. The bonding component may consist essentially of a polyamide or a polyester or of polystyrene or a copolymer of styrene with another monomer copolymerizable therewith, suitably a copolymer soluble in trichloroethylene, tetrachloroethylene, benzene, toluene, xylene, tetrachloromethane, dimethyl acetamide, dimethyl sulphoxide or dimethyl formamide. The composite filamentary segments may have a denier not exceeding 2À0; where the segments have a circular cross-section their denier preferably should not exceed 0À8, and where they have an irregularly shaped crosssection their denier preferably should not exceed 1À2. In the case of the last-mentioned type, at least one segment in the composite filamentary segment may have a straight surface in cross-section, and the cross-section of the composite filamentary segment may have at least one area the boundary of which comprises two straight lines meeting at a point; the preferred cross-section is trilobal. The complex conjugate filaments may be made by a process comprising the following steps which are carried out in a melt-spinning pack; (1) producing a plurality of composite synthetic polymer melt streams disposed apart from each other, each of said streams being prepared by independently supplying two component streams of a melt of polymers having shrinking properties differing from one another to the spinning pack and bringing the component streams in contact with one another in an eccentric core-in-sheath or side-by-side arrangement with only limited mixing thereof at their interface, (2) bonding together the composite streams with a bonding stream of melt of fibre-forming synthetic polymer differing from said component polymers of said composite stream into a complex conjugate stream by bringing said composite streams in contact with said bonding streams and filling up the spaces between said composite streams by said bonding stream, with only limited mixing thereof at their interface, and (3) extruding said complex conjugate stream through an orifice of the spinneret plate of said spinning pack and cooling and solidifying said extruded complex conjugate stream to form a complex conjugate filament. A synthetic composite filament with crimp potential made from the complex conjugate filament either by dissolving out the bonding component, with a suitable solvent, or by reacting it with a solution of a reagent in which it is converted to soluble reaction products. Thus. a polyester bonding component may be removed by treatment with an aqueous alkali metal hydroxide, or a polyamide component by treatment with aqueous hydrogen chloride solution. In an example, a complex composite filament having a cross-section as shown in Fig. 2 is prepared from constituents X, Y and Z. X consists of a polyethylene terephthalate type copolyester containing 49 mol. per cent of isophthalic acid as an acid component and having an intrinsic viscosity of 0À85 (determined in orthochlorophenol at 25 C.) and 0À5% by weight of titanium dioxide powder, Y consists of a polyethylene terephthalate having an intrinsic viscosity of 0À75 and 0À5% of titanium dioxide powder and Z consists of polystyrene and 1% by weight of polyethylene glycol having a molecular weight of about 20,000. The complex conjugate filament is formed by simultaneously melt spinning the constituents X, Y and Z in the ratio 20 : 50 : 30 at a temperature of 285 C. using the spinning pack 6 shown in Fig. 1. The constituents X, Y and Z in molten condition are fed to the spinning pack 6 through the inlets 3, 4 and 5 and metered through the filter beds 7, 8 and 9 on their way to the spinneret 10. The X streams pass through the ducts 11, and meet the Y streams in the zones 12. Both streams then pass through the ducts in the form of composite streams in which the X stream is eccentrically embedded in the Y stream. The composite XY stream then meets the Z stream in the zones 14, the XY composite streams then pass through the ducts 15 embedded in the Z stream. The XYZ composite streams are then united in the chambers 16 to form a complex conjugate stream in which four XY composite streams are embedded in the Z constituent stream symmetrically with respect to the axis of the complex conjugate stream, as shown in Fig. 2. The complex conjugated streams are then extruded through the spinneret orifices 17. The melt extruded complex composite filaments are cooled and solidified by passage through a spinning chimney maintained at a temperature of 30 C. and thereafter drawn at a draw ratio of 2À6 and a temperature of 90 C., the denier of the resulting complex composite filaments being 5À2. The Z constituent was dissolved out of the filaments by immersing them in tetrachloromethane and the "core-in-sheath" type composite filaments each having the cross-section shown in Fig. 3 thereby obtained, the X component "core" being eccentrically disposed in the Y component "sheath".