POLYESTER FIBER HAVING HONEYCOMB-LIKE STRUCTURE AND ITS PREPARATION

PURPOSE:The titled fibers, having pores with a specific diameter, in the form of a honeycomb on the surface thereof, the feeling resembling that of the natural fibers and improved heat insulating properties and touch, by drawing undrawn polyester fibers in the presence of heated steam, and treating the drawn fibers with an alkali. CONSTITUTION:A polyester, e.g. polyethylene terephthalate, is melt extruded through a spinneret by an extruder to give undrawn fibers, which are then oiled, wound around feed rollers, and drawn between the feed rollers and draw rollers with heated steam to afford drawn fibers. The resultant drawn fibers are dipped in an aqueous solution of sodium hydroxide, and treated under boiling to give the aimed fibers having pores with a diameter >=0.1mu on the surface thereof in the form of a honeybomb. The total draw ratio is preferably 85% or more based on the maximal draw ratio.