Patent GB-1258759-A (GB)
IPC: D01D5/30
Filed: 1968-12-23
Abstract: 1,258,759. Stockings. KANEGAFUCHI BOSEKI K.K. 23 Dec., 1968 [21 Dec., 1967 (2); 9 Oct., 1968], No. 61062/68. Heading A3V. [Also in Divisions B5 and Dl]  A crimpable self-adhesive composite filament from which stockings may be made comprises at least two thermoplastic polymeric components differing in shrinkability which extend uniformly and continuously along the longitudinal axis of the filament and each of which continuously occupies a part of the peripheral surface of the filament, one component occupying from 5 to 30%, especially 5-20% of the peripheral surface area of the filament and being interposed into and bonded with the other component(s) in a wedge-shape, (Fig. 4), keyhole shape (Fig. 5) or modified wedge (Fig. 8) or keyhole shape (Fig. 9) as viewed in section, the length 1 of said wedge as so viewed being the same as or longer than its maximum width W (Fig. 4), or W' (Fig. 5). Preferably the length of the wedge is more than 1.5 times its width, and the volume occupied by the wedge-forming component is from 5 to 50% of the total volume of the filament. A filament having three components, A, B, and C is preferred, one of which C, has a latent adhesivity as compared with the other two and is that interposed into and bonded into the other two components in a wedge-shape, keyhole shape or modified wedge shape or keyhole shape, the other components A and B having different shrinkabilities. Desirably, the wedge-forming component has a softening and adhesion-commencement temperature at least 5C, and especially at least 10C, lower than that of the other components. Preferably, the wedge forming component and another component are nylon-6 and a copolymer of nylon-6 with polyhexamethylene isophthalamide respectively, or vice versa. Examples 1-3 and 6 and 7 illustrate the use of polyamide components; Example 4 the use of polyester and polyesterether components. Such filaments may be made by flowing two independent spinning materials, which may be the same or different, in opposite directions to each other in two ducts each connected to a common conduit and interposing a thin layerlike stream of another spinning material different from the above mentioned spinning materials between the two spinning material streams at the combined portion in such manner that the longitudinal direction of the cross-section of the thin layer is perpendicular to the direction of the opposite streams and that the thin layer is so positioned that one side of the layer-like stream is in contact with one side-wall of the duct, but the other side thereof is not in contact with the other sidewall of the duct, and then extruding the thus combined spinning materials through the conduit from an orifice. When the two independent streams are the same, a two-component composite filament can be obtained; when they are different, a three-component composite filament results. Thus by using a latent adhesive component as the thin layer-like stream, a two-or three component filament having latent adhesivity can be obtained. The extruded filaments are drawn at ambient or elevated temperature. A suitable spinneret for the process is disclosed in Specification 1,258,760. Figs. 4 and 5 and 6 and 7 (not reproduced) show two component filaments according to the invention, and Figs. 8 and 9 show three component filaments of the invention. The wedge or keyhole shaped component preferably comprises a polymer having high dyeability or latent adhesivity. Two component filaments so made have reduced latent adhesivity and reduced crimpability. Filaments having good crimpability and reduced latent adhesivity, which are especially suitable for making stretchable ladies' stockings, are obtained using a three component filament as in Figs. 8 and 9, consisting of two components having different heat shrinkabilities for providing crimpability and a third component having latent adhesivity. Adhesivity may be induced in the component having latent adhesivity by heat-treatment, especially using saturated steam. In making run-resistant stockings by selfadhesion of the filaments, the stockings are dyed, subjected to crimp-developing treatment and the filaments adhered during post boarding of the stockings, by heating for 10-60 sees., with saturated steam, suitably at 110-130C, under tension caused by the shrinking of the filaments.