Splittable multicomponent polyester fibers

Abstract

Mechanically divisible multicomponent fibers are disclosed having at least a first component comprised of poly(lactic acid) polymer and at least a second component comprised of an aromatic polyester. The multicomponent fibers are particularly useful in the manufacture of nonwoven structures, and in particular nonwoven structures used as synthetic suede.

That which is claimed:  
     
         1 . A splittable multicomponent fiber comprising: 
 at least one polymer component comprising a poly(lactic acid) polymer; and    at least one polymer component comprising an aromatic polyester polymer, wherein said multicomponent fiber is dissociable by mechanical means.    
     
     
         2 . The fiber of  claim 1 , wherein said multicomponent fiber is dissociable into a plurality of poly(lactic acid) microfilaments and aromatic polyester microfilaments.  
     
     
         3 . The fiber of  claim 1 , wherein said aromatic polyester polymer comprises a polymer selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, polyethylene napthalate, and copolymers and mixtures thereof.  
     
     
         4 . The fiber of  claim 1 , wherein said aromatic polyester is poly(ethylene terephthalate).  
     
     
         5 . The fiber of  claim 1 , wherein said fiber is selected from the group consisting of pie/wedge fibers, segmented round fibers, segmented oval fibers, segmented rectangular fibers, segmented ribbon fibers, and segmented multilobal fibers.  
     
     
         6 . The fiber of  claim 5 , wherein said fiber is a pie/wedge fiber.  
     
     
         7 . The fiber of  claim 1 , wherein the weight ratio of said poly(lactic acid) polymer component to said aromatic polyester polymer component ranges from about 80/20 to about 20/80.  
     
     
         8 . The fiber of  claim 7 , wherein the weight ratio of said poly(lactic acid) polymer component to said aromatic polyester polymer component is about 65:35 to about 35:65.  
     
     
         9 . The fiber of  claim 1 , wherein said fiber is selected from the group consisting of continuous filaments, staple fibers, and meltblown fibers.  
     
     
         10 . The fiber of  claim 9 , wherein said fiber is a staple fiber.  
     
     
         11 . The fiber of  claim 1 , wherein said multicomponent fiber is dissociable by mechanical operations selected from the group consisting of impinging the multicomponent fiber with high pressure water, carding the multicomponent fiber, crimping the fiber, and drawing the multicomponent fiber.  
     
     
         12 . The fiber of  claim 1 , wherein said aromatic polyester polymer is poly(ethylene terephthalate), the weight ratio of said poly(lactic acid) polymer component to said poly(ethylene terephthalate) polymer component is from about 65:35 to about 35:65, and the fiber has a pie/wedge configuration.  
     
     
         13 . A fiber bundle comprising a plurality of aliphatic polyester microfilaments and aromatic polyester microfilaments, said microfilaments originating from a common multicomponent fiber.  
     
     
         14 . The fiber bundle of  claim 13 , wherein said microfilaments are prepared by mechanically dissociating aliphatic polyester and aromatic polyester components of said multicomponent fiber.  
     
     
         15 . The fiber bundle of  claim 13 , wherein said aliphatic polyester microfilaments comprise poly(lactic acid).  
     
     
         16 . The fiber bundle of  claim 13 , wherein said aliphatic polyester microfilaments and said aromatic polyester microfilaments are receptive to dyeing with disperse dye to provide a uniformly dyed fiber bundle.  
     
     
         17 . The fiber bundle of  claim 13 , wherein said aromatic polyester microfilaments are formed of a polymer selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, polyethylene napthalate, and copolymers and mixtures thereof.  
     
     
         18 . The fiber bundle of  claim 17 , wherein said aromatic polyester is poly(ethylene terephthalate).  
     
     
         19 . The fiber bundle of  claim 18 , wherein said microfilaments have an average size ranging from about 0.05 to about 1.5 denier.  
     
     
         20 . The fiber bundle of  claim 13 , wherein said fiber bundle comprises about 8 to about 48 aliphatic polyester and aromatic polyester microfilaments.  
     
     
         21 . The fiber bundle of  claim 13 , wherein said fiber bundle is in the form of staple fiber.  
     
     
         22 . A yarn comprising the fiber bundle of  claim 13 .  
     
     
         23 . A microfilament comprising poly(lactic acid), said microfilament having an average size ranging from about 0.05 to about 1.5 denier and a tenacity ranging from about 1.0 to about 5.5 gpd tenacity.  
     
     
         24 . The microfilament of  claim 23 , wherein said poly(lactic acid) microfilament is a continuous filament.  
     
     
         25 . A yarn comprising the poly(lactic acid) microfilament of  claim 23 .  
     
     
         26 . A fabric comprising a plurality of splittable multicomponent fibers comprising at least one polymer component comprising a poly(lactic acid) polymer and at least one polymer component comprising an aromatic polyester polymer, wherein said multicomponent fibers are dissociable by mechanical means.  
     
     
         27 . A fabric comprising a plurality of poly(lactic acid) microfilaments and aromatic polyester microfilaments.  
     
     
         28 . The fabric of  claim 27 , wherein at least some of said poly(lactic acid) microfilaments and said aromatic polyester microfilaments originate from a common multicomponent fiber.  
     
     
         29 . The fabric of  claim 28 , wherein at least some of said poly(lactic acid) microfilaments and said aromatic polyester microfilaments are prepared by mechanically dissociating poly(lactic acid) components and aromatic polyester components of said multicomponent fiber.  
     
     
         30 . The fabric of  claim 26  or  27 , wherein said fabric is selected from the group consisting of nonwoven fabrics, woven fabrics, and knit fabrics.  
     
     
         31 . The fabric of  claim 26  or  27 , wherein said fabric is a nonwoven fabric selected from the group consisting of wet-laid nonwoven fabrics, dry-laid nonwoven fabrics, and direct-laid nonwoven fabrics.  
     
     
         32 . The fabric of  claim 26  or  27 , wherein said fabric is a dry-laid nonwoven fabric.  
     
     
         33 . The fabric of  claim 26  or  27 , wherein said fabric is a hydroentangled dry-laid nonwoven fabric.  
     
     
         34 . The fabric of  claim 26  or  27 , wherein said fabric further comprises a disperse dye.  
     
     
         35 . A product comprising the fabric of  claim 27 , selected from the group consisting of synthetic suede and filtration media.  
     
     
         36 . The product of  claim 35 , wherein said product is synthetic suede.  
     
     
         37 . A method for producing uniformly dyeable microfilament fibers, said method comprising: 
 extruding a plurality of multicomponent fibers comprising at least one polymer component comprising a poly(lactic acid) polymer and at least one polymer component comprising an aromatic polyester polymer; and    mechanically separating said multicomponent fibers to form a fiber bundle comprising a plurality of poly(lactic acid) microfilaments and aromatic polyester microfilaments.    
     
     
         38 . The method of  claim 37 , further comprising the step of disperse dyeing said poly(lactic acid) microfilaments and said aromatic polyester microfilaments simultaneously.  
     
     
         39 . The method of  claim 38 , further comprising the step of forming a yarn of said microfilaments prior to said dyeing step.  
     
     
         40 . A method for producing fabric, said method comprising: 
 extruding a plurality of multicomponent fibers comprising at least one polymer component comprising a poly(lactic acid) polymer and at least one polymer component comprising an aromatic polyester polymer;    forming a fabric from said multicomponent fibers; and    mechanically separating said multicomponent fibers to form a plurality of poly(lactic acid) microfilaments and aromatic polyester microfilaments, said separating step occurring prior to, during, or after said fabric forming step.    
     
     
         41 . The method of  claim 40 , further comprising the step of forming a yarn of said multicomponent fibers following said extrusion step and prior to said fabric forming step.  
     
     
         42 . The method of  claim 40 , wherein said step of forming a fabric comprises forming a woven fabric, forming a knit fabric, or forming a nonwoven fabric.  
     
     
         43 . The method of  claim 40 , further comprising after said extruding step the steps of: 
 forming a tow from a plurality of said multicomponent fibers;    drawing said tow;    crimping said fibers;    chopping said drawn tow into staple fibers; and    carding said crimped staple fibers to form a carded fiber web.    
     
     
         44 . The method of  claim 43 , further comprising the step of bonding said carded fiber web to form a unitary nonwoven fabric.  
     
     
         45 . The method of  claim 44 , wherein said bonding step is selected from the group consisting of needle punching and hydroentangling.  
     
     
         46 . The method of  claim 44 , wherein said separating step occurs simultaneously with at least one of said drawing step, crimping step, chopping step, carding step and bonding step.  
     
     
         47 . The method of  claim 40 , wherein said separating step occurs prior to said fabric forming step.  
     
     
         48 . The method of  claim 40 , wherein said separating step occurs after said fabric forming step.