Synthetic bast of linear polymeric thermoplastic material
<PICT:0864488/IV (a)/1> A synthetic bast-like material consisting of a flat, irregularly folded and at least partly agglutinated tubular filament is made by extruding a molten linear high polymeric thermoplastic material through an annular orifice in a spinneret, maintaining a slight superatmospheric gas pressure inside the tubular filament so formed, passing the filament, while still not completely hardened, through a cooling liquid and round a deflector therein, so as to flatten it, and withdrawing the filament under tension. Preferably the polymeric thermoplastic material melts between 100 DEG -300 DEG C. and is a polyamide or polyester. As shown, a spinneret 1 having an annular orifice 2 is fitted with a gas supply pipe 3 through which an inert gas, e.g. nitrogen, can be fed into the emerging tubular filament 4, which passes into cooling bath 5 and then under deflector rod 6 and over rod 7, being thereby flattened and folded by the action of the withdrawal tension exerted by the driven rollers 8. The filament is then stretched, preferably continuously with the spinning process, or subsequently as a separate process, in known manner, and wound up. The melt may be pigmented, or the final product may be dyed. The Provisional Specification refers also to the use, as a deflector, of a narrow passage exerting a squeezing and folding action on the tubular filament, or of a pair of rollers so constructed that irregular folding and creasing take place. Specification 533,307 is referred to.