Sea-island-type composite fiber, and fiber product including sea-island-type composite fiber

Abstract

A fiber is a sea-island-type composite fiber in which the primary constituent component of the sea section is an aromatic polyester, the moisture absorption/desorption parameter ΔMR is at least 2.0%, and a diagram obtained by connecting the center of gravity of the islands positioned on the outermost periphery of the fiber cross-sectional surface with line segments is a regular polygon having the center of gravity as an apex. A polyester fiber having superior quality with no splitting of the fiber surface caused by dispersion of stress generated due to volume expansion of the fibers when absorbing moisture, no dyeing irregularity or fuzzing when used in a woven or knitted fabric, and no reduction in moisture absorption due to hot-water processing.

1 - 4 . (canceled) 
     
     
         5 . A sea-island-type composite fiber comprising an aromatic polyester as a main constituent component of a sea part,
 wherein the fiber has a moisture absorption/release parameter ΔMR of 2.0% or more, and a figure obtained by connecting centroids of island parts disposed on an outermost periphery in a transverse section of the fiber with line segments is a regular polygon having the centroids as vertexes.   
     
     
         6 . The fiber according to  claim 5 , wherein a number of the island parts disposed on the outermost periphery in the transverse section of the fiber is an odd number. 
     
     
         7 . The fiber according to  claim 5 , wherein a ratio C/L of a radius of curvature C (μm) of a side on a fiber surface side of an outer periphery of an island part among the island parts disposed on the outermost periphery in the transverse section of the fiber to a radius L (μm) of a circumscribed circle including the island parts disposed on the outermost periphery in the transverse section of the fiber is 0.50 to 0.90. 
     
     
         8 . A fiber product comprising the sea-island-type composite fiber according to  claim 5 . 
     
     
         9 . The fiber according to  claim 6 , wherein a ratio C/L of a radius of curvature C (μm) of a side on a fiber surface side of an outer periphery of an island part among the island parts disposed on the outermost periphery in the transverse section of the fiber to a radius L (μm) of a circumscribed circle including the island parts disposed on the outermost periphery in the transverse section of the fiber is 0.50 to 0.90. 
     
     
         10 . A fiber product comprising the sea-island-type composite fiber according to  claim 6 . 
     
     
         11 . A fiber product comprising the sea-island-type composite fiber according to  claim 7 .