Abstract: A stretch yarn includes a multifilament including fibers having a coiled crimping form in a fiber axial direction, wherein a coil diameter distribution of crimping in the fiber has two or more groups, a ratio of a maximum group average value to a minimum group average value of the coil diameter (a maximum group average value/a minimum group average value) is less than 3.00, and a cross section of the fibers constituting the multifilament is an eccentric core-sheath cross section.

Abstract: A fiber material combines both stretchability and wear resistance, has a uniform and bump- and streak-free outer appearance, and has a smooth, delicate texture. The eccentric core-sheath composite fiber is characterized in that in the cross-section of a composite fiber composed of two different polymers, an A-component is completely covered by a B-component, a ratio S/D, or the minimum thickness S of the thickness of the B-component covering the A-component to a fiber diameter D, is 0.01 to 0.1, and a perimeter of a portion of fiber, where the thickness is 1.05 times or less the minimum thickness S, is at least one third of the perimeter of the fiber overall.

Abstract: A sea-islands type composite fiber includes an island component that is a polymer having moisture absorbability; a ratio (T/R) of a thickness T of an outermost layer to a diameter R of the fiber in a transverse cross section of the fiber of 0.05 to 0.25; and a moisture absorption rate difference (?MR) after a hot water treatment of 2.0 to 10.0%, wherein the thickness of an outermost layer is a difference between a radius of the fiber and a radius of a circumscribed circle formed by connecting apexes of the island components disposed in an outermost circle, and represents a thickness of a sea component in the outermost layer.