Surface modified bi-component polymeric fiber

Abstract

The present invention provides a bicomponent fiber having increased surface roughness. The fiber includes a first polymer and a composite, wherein the composite forms a layer which forms at least a portion of the fiber's surface. The composite is formed by a second polymer and a filler, where an average particle size of the filler can be greater than a thickness of the layer formed by the composite. The fibers can have a round, oval, trilobal, triangular, dog-boned, flat or hollow shape and a symmetrical or asymmetrical sheath/core or side-by-side configuration. When the fiber has a sheath/core configuration, the composite can form the sheath, and the average particle size of the filler can be greater than the thickness of the sheath.

1 . A bicomponent fiber having increased surface roughness comprising: 
 a first polymer; and    a composite comprising a second polymer and a filler, wherein the composite forms a layer that forms at least a portion of the fiber's surface, and wherein an average particle size of the filler is greater than a thickness of the layer formed by the composite.    
     
     
         2 . The bicomponent fiber of  claim 1 , wherein the bicomponent fiber has a sheath/core configuration, the sheath comprising the composite, the core comprising the first polymer, and wherein a thickness of the sheath is less than an average particle size of the filler.  
     
     
         3 . The bicomponent fiber of  claim 1 , wherein the first polymer is selected from the group consisting of a polyolefin, a di-block, tri-block or multi-block elastomeric copolymer, a polyurethane, a polyamide, a polyester, or combinations thereof.  
     
     
         4 . The bicomponent fiber of  claim 3 , wherein the di-block, tri-block, or multi-block elastomeric copolymer is selected from the group consisting of styrene-isoprene-styrene, styrene-butadiene-styrene, styrene-ethylene/butylene-styrene, styrene-ethylene/propylene-styrene, or combinations thereof.  
     
     
         5 . The bicomponent fiber of  claim 1 , wherein the first polymer comprises a polyolefin.  
     
     
         6 . The bicomponent fiber of  claim 5 , wherein the polyolefin is a homogenously branched polyolefin.  
     
     
         7 . The bicomponent fiber of  claim 5 , wherein the polyolefin is derived from at least one monomer selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, butadiene, cyclohexene, dicyclopentadiene, styrene, toluene, alpha-methylstyrene, or combinations thereof.  
     
     
         8 . The bicomponent fiber of  claim 1 , wherein the composite comprises an elastomeric polymer.  
     
     
         9 . The bicomponent fiber of  claim 8 , wherein the elastomeric polymer is selected from the group consisting of a homogenously branched polyolefin, a di-block, tri-block or multi-block elastomeric copolymer, a polyurethane, a polyamide, a polyester, or combinations thereof.  
     
     
         10 . The bicomponent fiber of  claim 9 , wherein the polyolefin is derived from at least one monomer selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, butadiene, cyclohexene, dicyclopentadiene, styrene, toluene, alpha-methylstyrene, or combinations thereof.  
     
     
         11 . The bicomponent fiber of  claim 1 , wherein the filler is selected form the group consisting of silica, alumina, calcium carbonate, silicon dioxide, a clay, or combinations thereof.  
     
     
         12 . The bicomponent fiber of  claim 1 , wherein the filler comprises calcium carbonate.  
     
     
         13 . The bicomponent fiber of  claim 1   1 , wherein the filler is coated with a compatibilizer.  
     
     
         14 . The bicomponent fiber of  claim 13 , wherein the compatibilizer is stearic acid.  
     
     
         15 . The bicomponent fiber of  claim 1 , wherein the composite comprises from about 1 to about 20 weight percent of the fiber.  
     
     
         16 . The bicomponent fiber of  claim 15 , wherein the composite comprises from about 5 to about 15 weight percent of the fiber.  
     
     
         17 . The bicomponent fiber of  claim 1 , wherein the filler comprises from about 1 to about 25 weight percent of the composite.  
     
     
         18 . The bicomponent fiber of  claim 1 , wherein the filler comprises from about 3 to about 15 weight percent of the composite.  
     
     
         19 . The bicomponent fiber of  claim 1 , wherein the average particle size of the filler ranges from about 0.1 to about 20 microns.  
     
     
         20 . The bicomponent fiber of  claim 1 , wherein a ratio of the average particle size of the filler to the composite layer thickness is greater than 1 and less than 2.  
     
     
         21 . The bicomponent fiber of  claim 20 , wherein a ratio of the average particle size of the filler to the composite layer thickness is from 1.2 to 1.8.  
     
     
         22 . The bicomponent fiber of  claim 1 , wherein a particle size distribution of the filler is less than 3.0.  
     
     
         23 . The bicomponent fiber of  claim 22 , wherein a particle size distribution of the filler is less than 2.0.  
     
     
         24 . The bicomponent fiber of  claim 1:   wherein a ratio of a filler particle center to center distance (L) to the average particle size (d) of the filler 
 a) is between about 3 and about 6 when the average particle size is less than 1 micron, or  
 b) is between about 2 and about 4 when the average particle size of the filler is 1 micron or greater;  
   wherein the center to center distance (L) is calculated as equal to (0.8/α av ) 1/2 d, where aav is the ratio of particle volume percentage to the polymer matrix volume percentage.    
     
     
         25 . The bicomponent fiber of  claim 1 , wherein the fiber is elastic.  
     
     
         26 . The bicomponent fiber of  claim 1 , wherein the fiber is crosslinked.  
     
     
         27 . An article comprising the fiber of  claim 1 .  
     
     
         28 . A method of forming a bicomponent fiber comprising: 
 blending a first polymer and a filler to form a composite;    coextruding under thermal bonding conditions a second polymer and the composite to form the bicomponent fiber;    wherein the second polymer forms the polymeric core and the composite forms a layer that forms at least a portion of a surface of the fiber; and    wherein an average particle size of the filler is greater than a thickness of the composite layer.    
     
     
         29 . The method of  claim 28  wherein the coextruding comprises forming a fiber having a round, oval, trilobal, triangular, dog-boned, flat or hollow shape and a symmetrical or asymmetrical sheath/core or side-by-side configuration.  
     
     
         30 . The method of  claim 29  wherein the bicomponent fiber has a round shape and a sheath/core configuration.  
     
     
         31 . In a method for manufacturing a bicomponent fiber by coextruding under thermal bonding conditions (a) a first polymer, and (b) a second polymer which forms a layer which forms at least a portion of the fiber's surface, the improvement comprising: 
 blending a filler with the second polymer to form a composite;    wherein the average particle size of the filler is greater than a thickness of the layer formed by the composite.    
     
     
         32 . A bicomponent fiber comprising a composite comprising a polymer and a filler wherein a composite forms a layer that forms at least a portion of the fiber's surface, and wherein an average particle size of the filler is greater than a thickness of the layer formed by the composite.