Multifilament yarn having novel configuration and a method for producing the same

摘要

A polyester yarn composed of a plurality of individual fibrous materials such as endless filaments or fibers. Each of these fibrous material is provided with cross-sectional thicker portions, thinner cross sectional portions and intermediate thickness-size portions randomly distributed along the axial direction thereof in a particular condition of distribution of cross-sections of these fibrous material. The above-mentioned polyester yarn involved a textured yarn applied to a drawn polyester multifilament yarn having the above-mentioned basic condition. To produce the polyester yarn according to the present invention, it is the basic condition that the undrawn polyester multifilament yarn should be drawn under a condition of a drawing ratio below a natural draw ratio of undrawn filaments of said undrawn multifilament yarn and a drawing temperature above a crystallizing initiating temperature of said undrawn filaments.