Method for preparing ultra-fine denier polyester filament yarn

The invention relates to a preparation method for super fine denier Terylene filament. The method adopts adopts cross air flow cooling process, to successfully produce a super fine denier terylene filament with monofilament size of 0.2 to 0.5 d.p.f. through adjusting calm zone height, adding a slow cooler and utilizing improved spin-spraying hole arrangement mode and oiling way during spinning process. The Terylene filament has sound spinnability and outstanding physical characteristics and processing performance.