Patent GB-1287945-A (GB)
IPC: D01D5/30
Filed: 1969-10-02
Abstract: 1287945 Conjugate filaments ASAHI KASEI KOGYO KK 2 Oct 1969 [2 Oct 1968 1 Nov 1968 (2)] 48582/69 Heading B5B Conjugate (side-by-side) filaments in which the boundary lines between the polymeric components thereof are highly and minutely irregular both when the filaments are viewed in crosssection and in longitudinal sections parallel to the filament axis are produced by feeding two or more molten fibre-forming synthetic organic thermoplastic polymers differing from one another in chemical composition and/or physical properties into a spinneret assembly or spinning head (Fig. 1) through separate inlets 1, 2, communicating with passageways 3 and 4 in which the streams of polymer melts contact one another. The contacting streams of polymer melts then pass through the ducts 5 which are packed with a particulate solid material which retains sufficient mechanical strength at the temperature if the polymer melts, and is chemically inert with respect to the polymers at the melt temperatures. The diameter of the particles is suitably 0À2 to 2 mm. and the height of the packings in the ducts 5 is over 5 mm. The passage of the polymer melts through the columns or layers of packing in the ducts distorts the interfacial surfaces between the polymer melts in a minute and highly irregular manner. The associated streams of polymer melts then pass through the conical passageway 6 and are extruded through the orifices 7 of the spinneret plate E in the form of conjugate filaments which are cooled and solidified in the usual manner. The particulate packing material may be metal or glass balls, sand, or powdered common salt. Alternatively the packing material may consist of wires piled lengthwise and breadthwise successively to form a checkered lattice structure, or may consists of a roll of glass wool held in place by wire gauze. Polymers which may be used for forming the filaments include polyamides, polyesters, polyolefins, polyvinyl chloride, polyvinyl alcohol, polyacetals, polyureas, polyurethanes, polyethers; polycarbonates, polyoxymethylenes, polyformals, and polyimides. The appearance of cross-sections of typical twocomponent conjugate filaments of the invention may be as shown in Fig. 3. The structure of the filaments may be such that when a cross-section of a filament is cut with a straight line which gives a maximum number of cross-points with the boundary between the polymers, the number of cross-points is more than 5; the length of the longest segment formed by two adjacent crosspoints is less than half the length of the said straight line; and two boundary lines at any two cross-sections one cm. apart from each other in one filament have different numbers of cross points, when cut by respective straight lines which give maximum number of cross points or, when two such boundary lines have the same number of cross-points, the lengths of the corresponding segments between two adjacent cross-points differ by more than 3% on average. Filaments so made may be stretched, e.g. by passing over a hot plate at 140‹C. at a draw ratio of 3À5 to 4, whereby fine crimps are immediately developed, or in water at 100‹ C., at a draw ratio of 8.