Biocomponent fibers and textiles made therefrom

Abstract

A bicomponent sheath core fiber is used to make a polymeric non-woven material having textile qualities. The sheath is an oriented polymer and the core is a polymer that flows or melts at a temperature lower than the melting point of the sheath. Non-woven mats are made of these fibers by treating the mat so that the core material melts, flows, and bonds to adjacent fibers in the non-woven mat. The non-woven material may have the qualities of a synthetic leather.

What is claimed is:  
     
         1 . A polymeric sheath core fiber, comprising: 
 a sheath material disposed about the periphery of a core material, the sheath material having a first melting point, and the core material comprising a material having a second melting point or a glass transition temperature at least about 10° C. less than the first melting point.    
     
     
         2 . The polymeric sheath core fiber of  claim 1 , wherein the sheath comprises an oriented semicrystalline polymer.  
     
     
         3 . The polymeric sheath core fiber of  claim 1 , wherein the second melting point or glass transition temperature is greater than about 35° C.  
     
     
         4 . The polymeric sheath core fiber of  claim 1 , wherein the diameter of the fiber is at least about 20 micrometers.  
     
     
         5 . The polymeric sheath core fiber of  claim 1 , wherein the sheath material selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.  
     
     
         6 . The polymeric sheath core fiber of  claim 1 , wherein the core material is selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.  
     
     
         7 . The polymeric sheath core fiber of  claim 1 , wherein the sheath comprises oriented polypropylene and the core is selected from polyethylene and a copolymer of ethylene and vinyl acetate.  
     
     
         8 . The polymeric sheath core fiber of  claim 1 , wherein the sheath comprises oriented polyethyleneterephthalate and the core is selected from a copolymer of an acid a glycol with ethylene terephthalate.  
     
     
         9 . A method of forming a polymeric non-woven textile, comprising: 
 providing a sheath core fiber having a sheath disposed about the periphery of a core, the fiber having a cross sectional shape, the sheath comprising an oriented semicrystalline polymer having a first melting point and the core comprising a material having a second melting point or a glass transition temperature at least 10° C. lower than the first melting point;    cutting the sheath core fiber to lengths of at least about 5 millimeters;    entangling the fibers to form a fiber mat; and    heating the fiber mat to melt the material in the core.    
     
     
         10 . The method of  claim 9  wherein the cutting step produces a fiber end that has a cross sectional shape that is the same as the cross sectional shape of the fiber.  
     
     
         11 . The method of  claim 9 , wherein the entangling step is done by hydroentangling.  
     
     
         12 . The method of  claim 9 , wherein the entangling step is done by needle punching.  
     
     
         13 . The method of  claim 9 , wherein the sheath material selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.  
     
     
         14 . The method of  claim 9 , wherein the core material is selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.  
     
     
         15 . A polymeric non-woven mat, comprising a sheath core fiber having a sheath material disposed about the periphery of a core material, the sheath material having a first melting point, and the core material comprising a material having a second melting point or a glass transition temperature at least about 10° C. less than the first melting point.  
     
     
         16 . The non-woven mat of  claim 15 , wherein the sheath comprises an oriented semicrystalline polymer.  
     
     
         17 . The non-woven mat of  claim 15 , wherein the diameter of the fiber is about 20 micrometers.  
     
     
         18 . The non-woven mat of  claim 15 , wherein the length of the fiber is at least about 5 millimeters.  
     
     
         19 . The non-woven mat of  claim 15 , further comprising one or more filler materials selected from the group of polyester, nylon, acrylic, wool, cotton, viscose, and silk.  
     
     
         20 . The non-woven mat of  claim 15 , wherein the sheath material is selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.  
     
     
         21 . The non-woven mat of  claim 15 , wherein the core material is selected from the group of homopolymers and copolymers of polyethylene, polypropylene, polymethylpentene, polytetrafluorethylene, polyamide, polyester, polyethylene oxide, polyoxymethylene, and cellulose acetate.