Thick-and-thin fibers and products therefrom

Abstract

Disclosed is a thick-and-thin fiber or fibers, wherein the fineness thereof changes gradually and periodically along the longitudinal direction thereof, and is characterized by (a) the thick-and-thin recurring length of five to 500 millimeters, (b) the thick-and-thin ratio of four to 50, (c) the average fineness of 0.05 to 2000 deniers, and (d) almost constant cross section areas at both the thick and the thin portions, respectively. Also disclosed is a thick-and-thin staple fiber or fibers formed therefrom by cutting the thick-and-thin fibers at a predetermined interval. Additionally, disclosed is a fabric made of the thick-and-thin fibers or staple fibers as a component thereof. Disclosed is a method to produce the thick-and-thin fibers comprising (1) a step wherein molten fiber forming polymer is extruded through spinneret holes at a constant throughput, (2) a step wherein the extruded filaments run through a short gaseous gap whose length is in the range of 0.1 to 6 millimeters before they plunge into liquid for the abrupt solidification by cooling, (3) a step wherein the solidified undrawn filaments are touched by at least one vibrating substance before being withdrawn at a constant speed, (4) a step wherein the undrawn filaments are drawn by some roller systems, and (5) a step wherein the drawn filaments are thermally set.