Composite fiber and method for forming the same

Abstract

A composite fiber is provided. The composite fiber includes a first region and a second region. The component of the first region includes a coloring agent and a resin. The component of the second region includes a crosslinked thermoplastic polymer and the crosslinked thermoplastic polymer includes gel particles with an average particle size no more than 1000 nm. A method for forming the composite fiber is also provided.

What is claimed is: 
     
         1 . A composite fiber, comprising:
 a first region, wherein the components of the first region comprise a resin; and   a second region, wherein the components of the second region comprise a crosslinked thermoplastic polymer;   wherein the crosslinked thermoplastic polymer comprises gel particles with an average particle size no larger than 1000 nm.   
     
     
         2 . The composite fiber as claimed in  claim 1 , wherein the components of the first region further comprise a coloring agent. 
     
     
         3 . The composite fiber as claimed in  claim 2 , wherein the weight percentage of the coloring agent in the components of the first region is ≦12 wt %. 
     
     
         4 . The composite fiber as claimed in  claim 1 , wherein the first region and the second region are connected through a van der Waals force. 
     
     
         5 . The composite fiber as claimed in  claim 1 , wherein the resin comprises polyester resin, polyamide resin, polyolefin resin, or a copolymer of the aforementioned resins. 
     
     
         6 . The composite fiber as claimed in  claim 1 , wherein the thermoplastic polymer is ethylene vinyl alcohol copolymer (EVOH), and the mole percentage of ethylene is 25˜50%. 
     
     
         7 . The composite fiber as claimed in  claim 1 , wherein the components of the second region are formed of 96˜99.79 wt % of the thermoplastic polymer, 0.1˜1.5 wt % of a crosslinking agent, 0.1˜1.5 wt % of a dispersant, and 0.01˜1 wt % of a crosslinking initiator. 
     
     
         8 . The composite fiber as claimed in  claim 7 , wherein the crosslinking agent is triallyl ester compound, triallyl amine compound, or a combination thereof. 
     
     
         9 . The composite fiber as claimed in  claim 8 , wherein the triallyl ester compound comprises triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), triallyl trimesate (TAM), or a combination thereof, and the triallyl amine compound comprises triallyl amine, triallyl-ammoniumcyanurate, or a combination thereof. 
     
     
         10 . The composite fiber as claimed in  claim 7 , wherein the dispersant comprises C 15-38  alkyl, C 15-38  ester, or a mixture thereof. 
     
     
         11 . The composite fiber as claimed in  claim 7 , wherein the crosslinking initiator comprises benzoyl peroxide, dicumyl peroxide, azobisisobutyronitrile, or a combination thereof. 
     
     
         12 . The composite fiber as claimed in  claim 1 , wherein the shear force (melt viscosity (η)×shear rate) of the components of the second region is 120˜20 Pa·s×4000˜12000 s −1  at 190˜220° C. 
     
     
         13 . The composite fiber as claimed in  claim 1 , wherein in a cross section of the composite fiber, the ratio of the areas of the first region and the second region is 10:90˜90:10. 
     
     
         14 . The composite fiber as claimed in  claim 1 , wherein in a cross section of the composite fiber, at least a portion of the second region is located at the outer peripheral portion of the cross section. 
     
     
         15 . The composite fiber as claimed in  claim 13 , wherein in a cross section of the composite fiber, the first region is a core portion and the second region is a shell portion. 
     
     
         16 . A method for forming a composite fiber, comprising:
 blending 96˜99.79 wt % of a thermoplastic polymer, 0.1˜1.5 wt % of a crosslinking agent, 0.1˜1.5 wt % of a dispersant to form a mixture;   adding 0.01˜1 wt % of a crosslinking initiator to the mixture and performing kneading to form a crosslinked thermoplastic polymer;   stranding and granulating the crosslinked thermoplastic polymer to form a crosslinked modified particle; and   performing a composite melt-spinning to the crosslinked modified particle and a resin.   
     
     
         17 . The method for forming the composite fiber as claimed in  claim 16 , wherein the thermoplastic polymer is ethylene vinyl alcohol copolymer (EVOH), and the mole percentage of ethylene is 25˜50%. 
     
     
         18 . The method for forming the composite fiber as claimed in  claim 16 , wherein the crosslinking agent comprises triallyl ester compound, triallyl amine compound, or a combination thereof. 
     
     
         19 . The method for forming the composite fiber as claimed in  claim 18 , wherein the triallyl ester compound comprises triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), triallyl trimesate (TAM), or a combination thereof, and the triallyl amine compound comprises triallyl amine, triallyl-ammoniumcyanurate, or a combination thereof. 
     
     
         20 . The method for forming the composite fiber as claimed in  claim 16 , wherein the kneading time is 1˜10 minutes, and the kneading temperature is 170˜230° C. 
     
     
         21 . The method for forming the composite fiber as claimed in  claim 16 , wherein the kneading is performed by using a twin-screw kneading machine. 
     
     
         22 . The method for forming the composite fiber as claimed in  claim 21 , wherein a rotating speed of the screw is 200˜300 rpm.