POLY(ETHYLENE TEREPHTHALATE) STAPLE FIBRE WITH IMPROVED DYEING CHARACTERISTICS

摘要

ABSTRACT OF THE DISCLOSUREPoly(ethylene terephthalate) filaments of enhanceddyeability, low boil-off shrinkage (even in as-spun condition),good thermal stability over a large temperature range, anduseful as texturing feed yarns and/or as hard yarns requiringno further drawing are prepared by spinning at a withdrawalspeed (V in yards/minute) of at least about 5500 yards/minuteand with a polymer temperature (Tp) measured (in °C) in thefilter pack at a point 50-100 mils above the center of thespinneret plate ofwherein (L) and (D) are the length and diameter (in mils) ofthe spinneret capillary and (w) is the throughput (in pounds/hour) per capillary. The filaments are characterized by along period spacing above 300 .ANG. in their as-spun condition,and, whether in as-spun condition or after heat-treatment, bya low skin-core value as measured by a differential birefrin-gence in relation to their stress measured at 20% extension(which correlates approximately with the spinning speed), alarge crystal size, and low amorphous orientation. Thecontinuous filament yarns may be draw-textured to providetextured yarns which also show enhanced dyeability. The staplefiber yarns also have very useful properties as compared withconventional staple yarns. A preferred process of spinningat these extremely high speeds is characterized by the use ofa spinneret with capillary-dimensions that produce high shearas the polyester is extruded and is applicable also to copoly-esters, whose filaments show a similar low skin-core in relationto their stress at 20% extension, the precise values for copoly-mers being different from the relationship for poly(ethyleneterephthalate).