Verfahren zur Herstellung von multilobalen Hochdenier-Filamenten aus thermotropischen Flüssigkristallpolymeren

摘要

The present invention discloses and claims a novel process for the formation of high denier as-spun and heat-treated multilobal filaments of a thermotropic liquid crystalline polymer. Preferred embodiments include process for the formation of as-spun and heat treated octalobal monofilaments of a few wholly aromatic polyesters and polyesteramides. The process involves (a) heating of a thermotropic liquid crystalline polymer to above its melting transition temperature; (b) passing said molten polymer through an extrusion chamber equipped with an extrusion capillary having a multilobal cross-section to form a multilobal filament; and (c) winding the filament at a suitable draw-down. The filaments so formed are of at least 50 denier per filament (dpf) and feature essentially uniform molecular orientation across their cross-section. In a final optional step, the filaments are heat treated in stages to form filaments exhibiting excellent tensile properties. Both as-spun and heat-treated filaments feature remarkably good tensile properties comparable to those of round filaments. Most importantly, the multilobal filaments of this invention feature much superior adhesion properties than the conventional round filaments.