Liquid crystal polyester fibers and method for producing same

Abstract

Provided are liquid crystal polyester fibers having a running tension variable width (R) of 5 cN or less and an oil component deposition rate of 3.0 wt % or less. Also provided is a method for producing liquid crystal polyester fibers whereby solid-phase polymerization is performed after applying inorganic particles (A) and phosphoric acid compound (B) to yarn obtained by melt spinning of liquid crystal polyester. Further provided is a mesh textile formed from the liquid crystal polyester fibers. By means of the liquid crystal polyester fibers, method for producing the same, and mesh textile, step transition and product yield during the weaving steps are excellent in that there is little scum and there is little variation of the running tension during the weaving steps.

1 . A liquid crystalline polyester fiber exhibiting a running tension fluctuation range (R) of 5 cN or less and an oil adhesion rate of 3.0 wt % or less. 
     
     
         2 . The liquid crystalline polyester fiber according to  claim 1 , wherein an amount of scum associated with the fiber is 0.01 g or less for 100,000 m of fiber generated at a rate of 400 m/min. 
     
     
         3 . The liquid crystalline polyester fiber according to  claim 1  whose strength is 12.0 cN/dtex or more. 
     
     
         4 . The liquid crystalline polyester fiber according to  claim 1 , wherein a half width of an endothermic peak (Tm 1 ) observed when measured under a condition of heating from 50° C. at a temperature elevation rate of 20° C./min in differential calorimetry is 15° C. or higher. 
     
     
         5 . The liquid crystalline polyester fiber according to  claim 1  which is a monofilament. 
     
     
         6 . The liquid crystalline polyester fiber according to  claim 1  which is composed of a single polymer component. 
     
     
         7 . The liquid crystalline polyester fiber according to  claim 1 , wherein the liquid crystalline polyester is composed of the following structural units (I), (II), (III), (IV), and (V) 
       
         
           
           
               
               
           
         
       
     
     
         8 . A method of producing a liquid crystalline polyester fiber comprising subjecting a yarn prepared by melt spinning a liquid crystalline polyester to a solid-phase polymerization after applying inorganic particles (A) and a phosphate-based compound (B) to said yarn. 
     
     
         9 . The method according to  claim 8 , further comprising cleaning said liquid crystalline polyester fiber after said solid-phase polymerization. 
     
     
         10 . The method according to  claim 9 , further comprising carrying out a high temperature heat treatment at a temperature of an endothermic peak temperature (Tm 1 ) of said liquid crystalline polyester fiber after said cleaning +10° C. or higher. 
     
     
         11 . The method according to  claim 8 , wherein said inorganic particles (A) are one or more selected from silica and silicates. 
     
     
         12 . The method according to  claim 8 , wherein said phosphate-based compound (B) comprises any of compounds represented by Formulae (1) to (3) or a combination thereof, and satisfies Conditions 1 to 4: 
       
         
           
           
               
               
           
         
         Condition 1: R 1  and R 2  represent a hydrocarbon group; 
         Condition 2: M 1  represents an alkali metal; 
         Condition 3: M 2  represents a group selected from an alkali metal, a hydrogen atom, a hydrocarbon group and a hydrocarbon group containing an oxygen atom(s); 
         Condition 4: n represents an integer of 1 or more. 
       
     
     
         13 . A mesh woven fabric comprising said liquid crystalline polyester fiber according  claim 1 . 
     
     
         14 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 2 . 
     
     
         15 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 3 . 
     
     
         16 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 4 . 
     
     
         17 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 5 . 
     
     
         18 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 6 . 
     
     
         19 . A mesh woven fabric comprising said liquid crystalline polyester fiber according to  claim 7 .