Sea-islands type composite fiber having excellent moisture absorbability, false twist yarn, and fiber structure

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 (ΔMR) 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.

1 .- 17 . (canceled) 
     
     
         18 . A sea-islands type composite fiber comprising:
 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 (ΔMR) 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.   
     
     
         19 . The sea-islands type composite fiber according to  claim 18 , wherein the thickness T of an outermost layer is 500 to 3,000 nm. 
     
     
         20 . The sea-islands type composite fiber according to  claim 18 , wherein the island component has a diameter r of 10 to 5,000 nm in the transverse cross section of the fiber. 
     
     
         21 . The sea-islands type composite fiber according to  claim 18 , wherein the island component is disposed to 2 to 100 circles in the transverse cross section of the fiber. 
     
     
         22 . The sea-islands type composite fiber according to  claim 18 , comprising a ratio (r1/r2) of a diameter r1 of the island component disposed to pass through a center of the transverse cross section of the fiber to a diameter r2 of other island components of 1.1 to 10.0. 
     
     
         23 . The sea-islands type composite fiber according to  claim 18 , wherein a shape of a center side of the island component disposed in an outermost circle in the transverse cross section of the fiber is non-circular. 
     
     
         24 . The sea-islands type composite fiber according to  claim 18 , comprising a composite ratio (a weight ratio) of the sea component/the island component of 50/50 to 90/10. 
     
     
         25 . The sea-islands type composite fiber according to  claim 18 , wherein the polymer having moisture absorbability is at least one polymer selected from the group consisting of a polyetherester, a polyether amide, and a polyetherester amide containing a polyether as a copolymerization component. 
     
     
         26 . The sea-islands type composite fiber according to  claim 25 , wherein the polyether is at least one polyether selected from the group consisting of polyethylene glycol, polypropylene glycol, and polybutylene glycol. 
     
     
         27 . The sea-islands type composite fiber according to  claim 25 , wherein the polyether has a number average molecular weight of 2,000 to 30,000 g/mol. 
     
     
         28 . The sea-islands type composite fiber according to  claim 25 , wherein a copolymerization ratio of the polyether is 10 to 60% by weight. 
     
     
         29 . The sea-islands type composite fiber according to  claim 25 , wherein the polyetherester contains an aromatic dicarboxylic acid and an aliphatic diol as main components, and contains the polyether as a copolymerization component. 
     
     
         30 . The sea-islands type composite fiber according to  claim 25 , wherein the polyetherester contains an aromatic dicarboxylic acid and an aliphatic diol as main components, and contains the polyether and an alkylene oxide adduct of a bisphenol represented by Formula (1) below as copolymerization components: 
       
         
           
           
               
               
           
         
       
       wherein m and n are integers of 2 to 20 and m+n is 4 to 30. 
     
     
         31 . The sea-islands type composite fiber according to  claim 29 , wherein the aliphatic diol is 1,4-butanediol. 
     
     
         32 . The sea-islands type composite fiber according to  claim 18 , wherein the sea component is a cation dyeable polyester. 
     
     
         33 . A false twist yarn comprising a twist of two or more of the sea-islands type composite fiber according to  claim 18 . 
     
     
         34 . A fiber structure comprising the sea-islands type composite fiber according to  claim 18  in at least a part of the fiber structure. 
     
     
         35 . A fiber structure comprising the false twist yarn according to  claim 33  in at least a part of the fiber structure.