Multicomponent fibers and microdenier fabrics prepared by fibrillation thereof

Abstract

Multicomponent fibers and fabrics made therefrom are provided. The fibers include a multilobal sheath fiber component surrounding a core fiber component, wherein the fibers can be fibrillated to provide a plurality of intertwined microdenier fiber components. Methods of providing such fabrics are also disclosed.

1 . A multicomponent fiber comprising: a contiguous core fiber component completely enwrapped by a multilobal sheath fiber component such that the sheath fiber component forms the entire outer surface of the multicomponent fiber, wherein the core fiber component and the lobes of the multilobal sheath fiber component are each microdenier sized, and wherein the multicomponent fiber is configured to fibrillate into a plurality of intertwined microdenier fiber components when mechanical energy is introduced to the multicomponent fiber. 
     
     
         2 . The multicomponent fiber of  claim 1 , wherein the multilobal sheath has from 3 to about 18 lobes. 
     
     
         3 . The multicomponent fiber of  claim 1 , wherein the core is solid. 
     
     
         4 . The multicomponent fiber of  claim 1 , wherein the core has a cross-sectional shape selected from the group consisting of circular, rectangular, square, oval, triangular, and multilobal. 
     
     
         5 . The multicomponent fiber of  claim 1 , where at least one of the core fiber component and the sheath fiber component comprises a polymer selected from the group consisting of: polyesters; polyamides; copolyetherester elastomers; polyolefins; polyurethanes; polyvinylidene fluoride; polyacrylates; cellulose esters; liquid crystalline polymers; and mixtures thereof. 
     
     
         6 . The multicomponent fiber of  claim 1 , wherein at least one of the core fiber component and the sheath fiber component comprises a polymer selected from the group consisting of nylon 6; nylon 6/6; nylon 6,6/6; nylon 6/10, nylon 6/11; nylon 6/12; and mixtures thereof. 
     
     
         7 . The multicomponent fiber of  claim 1 , wherein the core component comprises an elastomer. 
     
     
         8 . The multicomponent fiber of  claim 7 , wherein the elastomer is selected from the group consisting of styrene-butadiene rubber, butadiene rubber, polyisoprene, polyisoprene-polystyrene copolymer, polychloroprene, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, butyl rubber, ethylene-propylene rubber, silicone rubber, chlorosulfonated polyethylene, polyacrylate rubber, fluorocarbon rubber, chlorinated polyethylene rubber, epichlorhydrin rubber, ethylene-vinylacetate copolymer, and urethane rubber. 
     
     
         9 . The multicomponent fiber of  claim 1 , wherein the core fiber component comprises from about 10% to about 90% by volume of the multicomponent fiber. 
     
     
         10 . The multicomponent fiber of  claim 1 , wherein the core fiber component comprises from about 20% to about 80% by volume of the multicomponent fiber. 
     
     
         11 . The multicomponent fiber of  claim 1 , wherein the volume ratio of core fiber component to multilobal sheath fiber component is about 25:75, about 50:50, or about 75:25. 
     
     
         12 . The multicomponent fiber of  claim 1 , wherein the multilobal sheath fiber component has a lower viscosity than the core fiber component. 
     
     
         13 . The multicomponent fiber of  claim 1 , wherein the sheath fiber component comprises a non-elastomeric thermoplastic polymer. 
     
     
         14 . The multicomponent fiber of  claim 13 , wherein the non-elastomeric thermoplastic polymer is selected from the group consisting of polyesters, polyamides, polyolefins, polyurethanes, polyacrylates, cellulose esters, liquid crystalline polymers, and mixtures thereof. 
     
     
         15 . A nonwoven fabric comprising a plurality of intertwined microdenier fiber components, the intertwined microdenier fiber components being in the form of fibrillated multicomponent fibers that included a contiguous core fiber component completely enwrapped by a multilobal sheath fiber component such that the sheath fiber component forms the entire outer surface of the multicomponent fiber prior to fibrillation, wherein the core fiber component and the lobes of the multilobal sheath fiber component are each microdenier sized. 
     
     
         16 . The nonwoven fabric of  claim 15 , where at least one of the core fiber component and the multilobal sheath fiber component comprises a polymer selected from the group consisting of: polyesters; polyamides; copolyetherester elastomers; polyolefins; polyurethanes; polyvinylidene fluoride; polyacrylates; cellulose esters; liquid crystalline polymers; and mixtures thereof. 
     
     
         17 . The nonwoven fabric of  claim 15 , wherein at least one of the core fiber component and the multilobal sheath fiber component comprises a polymer selected from the group consisting of nylon 6; nylon 6/6; nylon 6,6/6; nylon 6/10, nylon 6/11; nylon 6/12; and mixtures thereof. 
     
     
         18 . The nonwoven fabric of  claim 15 , wherein the core fiber component is an elastomer. 
     
     
         19 . The nonwoven fabric of  claim 18 , wherein the elastomer is selected from the group consisting of styrene-butadiene rubber, butadiene rubber, polyisoprene, polyisoprene-polystyrene copolymer, polychloroprene, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, butyl rubber, ethylene-propylene rubber, silicone rubber, chlorosulfonated polyethylene, polyacrylate rubber, fluorocarbon rubber, chlorinated polyethylene rubber, epichlorhydrin rubber, ethylene-vinylacetate copolymer, and urethane rubber. 
     
     
         20 . The nonwoven fabric of  claim 15 , wherein the multilobal sheath has 3 to about 18 lobes. 
     
     
         21 . The nonwoven fabric of  claim 15 , wherein the fabric exhibits a moisture vapor permeability of at least about 18,000 g/sq. m/day. 
     
     
         22 . The nonwoven fabric of  claim 15 , wherein the fabric exhibits a tongue tear strength of at least about 5 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         23 . The nonwoven fabric of  claim 15 , wherein the fabric exhibits a grab tensile strength in the machine direction of at least about 120 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         24 . The nonwoven fabric of  claim 15 , wherein the fabric exhibits a grab tensile strength in the cross-machine direction of at least about 60 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         25 . The nonwoven fabric of  claim 15 , wherein the fabric has a machine direction or cross-machine direction stretch and recovery characterized by a minimum stretch of at least about 5%. 
     
     
         26 . The nonwoven fabric of  claim 15 , wherein the fabric has a stretch of greater than about 30%. 
     
     
         27 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 30% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 10 seconds after the dead weight is removed. 
     
     
         28 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 30% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 10 seconds after the dead weight is removed. 
     
     
         29 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 1 hour after the dead weight is removed. 
     
     
         30 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 1 hour after the dead weight is removed. 
     
     
         31 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 24 hours after the dead weight is removed. 
     
     
         32 . The nonwoven fabric of  claim 15 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 24 hours after the dead weight is removed. 
     
     
         33 . The nonwoven fabric of  claim 15 , wherein the fabric is prepared from multicomponent, multilobal fibers comprising a polyester sheath fiber component and wherein the fabric has a burst strength from about 20 to about 60 PSI. 
     
     
         34 . The nonwoven fabric of  claim 15 , wherein the fabric is prepared from multicomponent, multilobal fibers comprising a nylon-6 sheath fiber component and wherein the fabric has a burst strength from about 60 to about 120 PSI. 
     
     
         35 . A method of producing a nonwoven fabric in the form of a web suitable for use in forming a nonwoven article, comprising:
 spinning a set of multicomponent fibers comprising a contiguous core fiber component completely enwrapped by a multilobal sheath fiber component such that the sheath fiber component forms the entire outer surface of the multicomponent fiber, wherein the core fiber component and the lobes of the multilobal sheath fiber component are each microdenier sized;   positioning said set of multicomponent fibers onto a web;   fibrillating the multicomponent fibers positioned on the web by introduction of mechanical energy to the set of multicomponent fibers, the fibrillating step causing the lobes of the multilobal sheath fiber component to separate from and expose the core fiber component and intertwine with the core fiber component to form a web of entangled fiber components.   
     
     
         36 . The method of  claim 35 , where at least one of the core fiber component and the multilobal sheath fiber component comprises a polymer selected from the group consisting of: polyesters; polyamides; copolyetherester elastomers; polyolefins; polyurethanes; polyvinylidene fluoride; polyacrylates; cellulose esters; liquid crystalline polymers; and mixtures thereof. 
     
     
         37 . The method of  claim 35 , wherein at least one of the core fiber component and the multilobal sheath fiber component comprises a polymer selected from the group consisting of nylon 6; nylon 6/6; nylon 6,6/6; nylon 6/10, nylon 6/11; nylon 6/12; and mixtures thereof. 
     
     
         38 . The method of  claim 35 , wherein the core fiber component is an elastomer. 
     
     
         39 . The method of  claim 38 , wherein the elastomer is selected from the group consisting of styrene-butadiene rubber, butadiene rubber, polyisoprene, polyisoprene-polystyrene copolymer, polychloroprene, acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, butyl rubber, ethylene-propylene rubber, silicone rubber, chlorosulfonated polyethylene, polyacrylate rubber, fluorocarbon rubber, chlorinated polyethylene rubber, epichlorhydrin rubber, ethylene-vinylacetate copolymer, and urethane rubber. 
     
     
         40 . The method of  claim 35 , wherein the multilobal sheath has 3 to about 18 lobes. 
     
     
         41 . The method of  claim 35 , further comprising generating a fabric from the web of entangled fiber components. 
     
     
         42 . The method of  claim 41 , where the fabric exhibits a moisture vapor permeability of at least about 18,000 g/sq. m/day. 
     
     
         43 . The method of  claim 41 , wherein the fabric exhibits a tongue tear strength of at least about 5 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         44 . The method of  claim 41 , wherein the fabric exhibits a grab tensile strength in the machine direction of at least about 120 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         45 . The method of  claim 41 , wherein the fabric exhibits a grab tensile strength in the cross-machine direction of at least about 60 lbs for a fabric with a basis weight of 135 gsm. 
     
     
         46 . The method of  claim 41 , wherein the fabric has a machine direction or cross-machine direction stretch and recovery characterized by a minimum stretch of at least about 5%. 
     
     
         47 . The method of  claim 41 , wherein the fabric has a stretch of greater than about 30%. 
     
     
         48 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 30% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 10 seconds after the dead weight is removed. 
     
     
         49 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 30% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 10 seconds after the dead weight is removed. 
     
     
         50 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 1 hour after the dead weight is removed. 
     
     
         51 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 1 hour after the dead weight is removed. 
     
     
         52 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 100 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 24 hours after the dead weight is removed. 
     
     
         53 . The method of  claim 41 , wherein a 1″×6″ piece of the fabric with a basis weight of 150 g/m 2  has a recovery of at least about 80% when the fabric length is measured before a dead weight of 3 pounds is hung from the piece of fabric and 24 hours after the dead weight is removed. 
     
     
         54 . The method of  claim 41 , wherein the fabric is prepared from multicomponent, multilobal fibers comprising a polyester sheath fiber component and wherein the fabric has a burst strength from about 20 to about 60 PSI. 
     
     
         55 . The method of  claim 41 , wherein the fabric is prepared from multicomponent, multilobal fibers comprising a nylon-6 sheath fiber component and wherein the fabric has a burst strength from about 60 to about 120 PSI.