METHOD FOR PRODUCING HIGHLY COLORING SYNTHETIC FIBER YARN

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a highly coloring synthetic fiber yarn capable of suppressing fiber surface reflection, having a depth in color and improved in dye exhaustion ratio without whitishness. SOLUTION: A synthetic fiber multifilament yarn is intermittently and instantaneously brought into contact with a high-temperature heating unit, thereby intermittently and instantaneously heat-treated at a high temperature to apply heat treatment in an uneven manner in the fiber axial direction and fiber- sectional direction of the multifilament yarn and then heat-treated under relaxed conditions.