POLYAMIDE FIBERS COMPOSED OF THE POLYAMIDE AND METHODS FOR PRODUCING THEREOF

1304865 Polyamide composite and other filaments KANEGAFUCHI BOSEKI KK 26 Aug 1970 [27 Aug 1969 4 Dec 1969 13 April 1970 21 April 1970 23 April 1970 26 May 1970] 41092/70 Heading B5B [Also in Division C3] Polyamide composed of at least 95 wt. per cent of units where n is 3 or 4 (see Division C3) are spun into fibres alone or as a component of a side-by-side or sheath and core bicomponent fibre. Fibre formation and properties are described with particular emphasis being given to: (a) Drawing a melt spun polymer until the double refractive index is at least 0À07 using, e.g., a pin or plate, at temperatures up to 200‹ C., at a higher draw ratio than is usual for nylon 6 or 66, e.g. 3À6 to 6À0 for 0À25 mm. filaments taken up at 600 m./min. (b) Overcoming sticking of fibres during (a) by (i) incorporating a compound containing a polymethylene group of at least 8 C atoms in the polyamide, e.g. a paraffinic hydrocarbon, an ethylene polymer or nylon 11, 12, 610 or 612; (ii) drawing without winding up after spinning; or (iii) crystallizing the filament as much as possible before taking up, e.g., by passing the just extruded filament through a cooling zone maintained at T 1 ‹C. according to the relationship 30+5n#T 1 #200-5n, and (c) further heat treatment of drawn filaments to improve the modulus. Composite filaments formed using the polyamides as one component may have one of thecross-sections shown in Figs. 1 to 11. The composite filament may be of triangular crosssection. Specified second components are polyamides, polyesters, polyethers and polyolefins, e.g. nylons 4, 6, 66 and 61, polymetaxylylene adipamide, poly-paraxylylene or -bis-(cyclohexylene) methane decanamide, polyethylene terephthalate or oxybenzoate and poly-tetramethylene or -dimethylcyclohexylene terephthalate. The polyamide desirably forms at least part of the surface to obtain the benefit of its antistatic properties.