Fiber bundle for artificial hair, and process for its production

Abstract

To provide a fiber bundle for artificial hair which has a well balanced combination of properties such as bulkiness, yarn separability, weaving efficiency and hot water-curling efficiency. The fiber bundle for artificial hair is a fiber bundle obtained by crimping fibers (A) having a flexural rigidity of from 0.7 to 2.5 gf·cm 2 as measured by the KES method and has a crimp wave shape satisfying the following formula: 1 mm≦R≦20 mm wherein R is the distance between the top and the bottom of the crimp wave shape. Further, in the fiber bundle for artificial hair, the fibers (A) are vinyl chloride fibers obtained by melt-spinning a vinyl chloride resin composition.

1 . A fiber bundle for artificial hair, which is a fiber bundle obtained by crimping fibers (A) having a flexural rigidity of from 0.7 to 2.5 gf·cm 2  as measured by the KES method and which has a crimp wave shape satisfying the following formula:
   1 mm≦R≦20 mm   
     wherein R is the distance between the top and the bottom of the crimp wave shape. 
   
   
       2 . The fiber bundle for artificial hair according to  claim 1 , wherein the fibers (A) have a fineness of monofilament of from 20 to 100 decitex. 
   
   
       3 . The fiber bundle for artificial hair according to  claim 1 , wherein the fibers (A) are vinyl chloride fibers obtained by melt-spinning a vinyl chloride resin composition. 
   
   
       4 . The fiber bundle for artificial hair according to  claim 3 , wherein the vinyl chloride resin composition comprises a vinyl chloride resin and from 0.5 to 10 parts by mass, per 100 parts by mass of the vinyl chloride resin, of a chlorinated vinyl chloride resin. 
   
   
       5 . The fiber bundle for artificial hair according to  claim 4 , which further contains a thermal stabilizer. 
   
   
       6 . The fiber bundle for artificial hair according to  claim 5 , wherein the thermal stabilizer is at least one member selected from the group consisting of a Ca—Zn type thermal stabilizer, a hydrotalcite type thermal stabilizer, a tin type thermal stabilizer and a zeolite type thermal stabilizer. 
   
   
       7 . The fiber bundle for artificial hair according to  claim 1 , wherein the cross-sectional shape of the fibers (A) is a Y-shape, a H-shape, a U-shape, a C-shape or a X-shape. 
   
   
       8 . The fiber bundle for artificial hair according to  claim 1 , wherein the crimping is gear-crimping. 
   
   
       9 . The fiber bundle for artificial hair according to  claim 1 , which is for head decoration. 
   
   
       10 . A braid using the fiber bundle for artificial hair as defined in  claim 9 . 
   
   
       11 . A process for producing a fiber bundle for artificial hair comprising:
 (a) mixing a vinyl chloride resin composition comprising a vinyl chloride resin and a thermal stabilizer,   (b) melt-spinning the vinyl chloride resin composition from a spinneret at a spinneret temperature of from 160 to 190° C.,   (c) stretching the melt-spun fibers (A) in an atmosphere at a stretching temperature of from 90 to 120° C. at a stretching ratio of from 200 to 400%.   (d) subjecting the stretched fibers (A) to thermal relaxing treatment in an atmosphere of air at a temperature of from 110 to 140° C. until the entire length of the fibers becomes from 60 to 95% of the length before the treatment, and   (e) gear-crimping the fibers (A) treated for thermal relaxing, at a gear surface temperature of from 30 to 100° C. at a crimping rate of from 0.5 to 10 m/min, wherein (a) to (e) occur sequentially.   
   
   
       12 . The fiber bundle for artificial hair according to  claim 5 , wherein the thermal stabilizer is at least one member selected from the group consisting of a Ca—Zn thermal stabilizer, a hydrotalcite thermal stabilizer, a tin thermal stabilizer and a zeolite thermal stabilizer. 
   
   
       13 . The fiber bundle for artificial hair as defined in  claim 9 , in the form of a braid.