Extensible fibers and nonwovens made from large denier splittable fibers

Abstract

The present invention provides fibers (e.g. for nonwovens) that have high elongation to break at moderate to low fiber diameters. This is accomplished by spinning splittable multicomponent fibers under appropriate conditions to produce large diameter, low orientation fibers which can then be split into smaller segments that maintain the properties of the parent fiber. Thus, fibers are produced having elongations significantly higher than if a fiber of that same size had been spun directly.

What is claimed is:  
     
         1 . A splittable composite fiber comprising at least two thermoplastic resin components, wherein said composite fiber has a diameter ≧40 microns, wherein said composite fiber is capable of being split into at least two fibers each having a diameter ≦30 microns, and wherein said split fibers have greater elongation to break values than fibers of the same size that are obtained by direct spinning.  
     
     
         2 . The split fibers obtained by splitting the splittable composite fiber of  claim 1 .  
     
     
         3 . The splittable composite fiber of  claim 1  wherein the at least two thermoplastic resin components are selected from the group consisting of polyolefins, polyesters, polyamides, and copolymers and mixtures thereof.  
     
     
         4 . The splittable composite fiber of  claim 3  wherein the at least two thermoplastic resin components comprise polypropylene as a first component and polyethylene as a second component.  
     
     
         5 . A nonwoven web comprising the splittable composite fibers of  claim 1 .  
     
     
         6 . A nonwoven web comprising the splittable composite fibers of  claim 4 .  
     
     
         7 . A laminate comprising the nonwoven web of  claim 5 .  
     
     
         8 . A disposable absorbent article comprising the nonwoven web of  claim 5 .  
     
     
         9 . A disposable absorbent article comprising the laminate of  claim 7   
     
     
         10 . The splittable composite fiber of  claim 1  wherein said fiber has a cross-section selected from the group consisting of side by side, segmented pie, hollow segmented pie, segmented ribbon, tipped multilobal, and mixtures thereof.  
     
     
         11 . The splittable composite fiber of  claim 10  wherein said fiber cross-section is selected from the group consisting of segmented pie, hollow segmented pie, and mixtures thereof.  
     
     
         12 . The splittable composite fiber of  claim 11  wherein said fiber cross-section is a hollow segmented pie.  
     
     
         13 . The splittable composite fiber of  claim 1  wherein the fiber has a shape selected from the group consisting of round, elongated, multilobal, and mixtures thereof.  
     
     
         14 . The splittable composite fiber of  claim 13  wherein said fiber shape is round.  
     
     
         15 . The splittable composite fiber of  claim 14  wherein said fiber cross-section is hollow segmented pie.  
     
     
         16 . The splittable composite fiber of  claim 15  wherein the at least two thermoplastic resin components comprise polypropylene as a first component and polyethylene as asecond component.  
     
     
         17 . The split fibers obtained by splitting the splittable composite fiber of  claim 4 .  
     
     
         18 . The split fibers obtained by splitting the splittable composite fiber of  claim 12 .  
     
     
         19 . The split fibers of  claim 2  wherein said split fibers are obtained from the splittable composite fiber by a process selected from the group consisting of stretching, hydroentangling, needling, aqueous treatment, chemical treatment, thermal treatment, and mixtures thereof.  
     
     
         20 . The nonwoven web of  claim 5  wherein said nonwoven is bonded by a process selected from the group consisting of thermal point bonding, through-air bonding, hydroentangling, ultrasonic bonding, and mixtures thereof.