Wound Yard Body of Water Absorbent Polyester Fiber and Method for Manufacturing Same

Abstract

A wound yarn body of a water-absorbent polyester fiber having a water absorbency under JIS L1907: 2010 falling-drop method after being washed 30 times under JIS L0217: 1995 103 C method of 5 seconds or less, the wound yarn body being characterized in that the deposition amount of white powder containing a cyclic oligomer that is the decomposition product of polyester constituting the water-absorbent polyester fiber is less than 0.3 wt %; and a method for manufacturing the wound yarn body that includes a process for applying alkali reduction to a polyester fiber containing 0.005-1 wt % of an element S at reduction rate of a 0.6-9% against the polyester fiber.

1 : A wound yarn body of a water absorbent polyester fiber having water absorbency as determined by the falling-drop method of JIS L1907:2010 after washing 30 times according to Method 103 C of JIS L0217:1995 of 5 seconds or less; wherein the adhered amount of a white powder containing a cyclic oligomer that is a decomposition product of the polyester that composes the water absorbent polyester fiber is less than 0.3% by weight. 
     
     
         2 : The wound yarn body according to  claim 1 , wherein the water absorbent polyester fiber contains 0.005% by weight to 1% by weight of elemental S and 95 mol % or more of the repeating units of the polyester is ethylene terephthalate. 
     
     
         3 : The wound yarn body according to  claim 1 , wherein a terminal carboxylic acid linear oligomer component represented by the following formula (1): 
       
         
           
           
               
               
           
         
       
       (wherein n is an integer of 3 to 10) is present on the surface of the water absorbent polyester fiber, and among the terminal carboxylic acid linear oligomer components, the terminal carboxylic acid linear oligomer component in which n=4 is contained in an amount equivalent to the concentration as internal standard of 2 μg/ml to 15 μg/ml. 
     
     
         4 : The wound yarn body according to  claim 1 , wherein the wound amount of the water absorbent polyester fiber is 0.5 kg to 4 kg per single wound yarn body. 
     
     
         5 : The wound yarn body according to  claim 1 , wherein the water absorbent polyester fiber is a false twisted yarn. 
     
     
         6 : The wound yarn body according to  claim 1 , wherein the water absorbent polyester fiber does not have needle loop-shaped crimps. 
     
     
         7 : A method for manufacturing the wound yarn body according to  claim 2 , comprising a step for carrying out alkali reduction on the polyester fiber containing 0.005% by weight to 1% by weight of elemental S at a reduction rate of 0.6% to 9% with respect to the polyester fiber. 
     
     
         8 : The method according to  claim 7 , wherein a chelating agent is used in combination in the step for carrying out alkali reduction and an oligomer dispersant is further used in combination during soaping and neutralization.