Method for melt spinning polyester filaments

摘要

A melt-extrusion process is disclosed for reducing the birefringence variability of melt-spun yarn made at high pack throughputs. It involves extruding polymer at an average mass-flow rate through a first group of orifices (defined by specific location in the spinnerette), that is greater than the mass-flow rate of polymer through a second group of orifices (also defined by location in the spinnerette). It is preferred that a spinnerette be used in which the dimensions of the orifices differ from group to group in a defined manner.