Elastomeric multicomponent fibers, nonwoven webs and nonwoven fabrics

Abstract

A bonded web of multi-component strands that include a first polymeric component and a second polymeric component is capable of overcoming a number of problems associated with nonwoven webs including both stickiness and blocking. The first polymeric component and second polymeric component are arranged in substantially distinct zones extending longitudinally along at least a portion of a length of the strands which make up the web with the second component containing a zone constituting at least a portion of the peripheral surface of the strand. The first polymeric component also has an elasticity which is greater than that of the second polymer component. A process producing elastomeric spunbonded nonwoven fabrics which utilizes the activation by incremental stretching of the strands is also provided.

1 . A method for producing an elastic nonwoven fabric, comprising: 
 incrementally stretching a nonwoven web in at least one direction to activate the elastic properties of the nonwoven web and to form the elastic nonwoven fabric,    wherein the nonwoven web comprises a plurality of multicomponent strands having first and second polymer components longitudinally coextensive along the length of the strands, said first component comprising an elastomeric polymer, and said second polymer component comprising a polymer less elastic than the first polymer component wherein least a portion of the multicomponent strands has a trilobal or tipped trilobal configuration.    
     
     
         2 . The method according to  claim 1 , wherein the nonwoven web is formed by: 
 melt spinning a plurality of multicomponent strands having first and second polymer components longitudinally coextensive along the length of the strands, said first component comprising an elastomeric polymer, and said second polymer component comprising a non-elastomeric polymer;    forming the multicomponent strands into a nonwoven web; and    bonding or intertwining the strands to form a coherent bonded nonwoven web.    
     
     
         3 . The method according to  claim 1 , wherein the step of incrementally stretching the web comprises stretching the fabric so that portions of the multicomponent strands are stretch-activated and become elastic, while other portions of the strands are not stretch-activated and are substantially less elastic.  
     
     
         4 . The method according to  claim 1 , wherein the incrementally stretching the web comprises stretching the fabric so that substantially all of the multicomponent strands are stretch-activated and become elastic.  
     
     
         5 . The method according to  claim 1 , wherein the incrementally stretching the web comprises incrementally stretching the web in both the machine direction and in the cross-machine direction.  
     
     
         6 . The method according to  claim 1 , wherein the incrementally stretching the web comprises directing the web through at least one pair of interdigitating stretching rollers.  
     
     
         7 . The method according to  claim 5 , wherein the directing the web through interdigitating stretching rollers includes forming narrow, spaced apart longitudinally extending stretch-activated elastic zones in the fabric, separated by intervening longitudinally extending non-activated zones that are substantially less elastic.  
     
     
         8 . The method according to  claim 1 , wherein the incrementally stretching the web comprises directing the web through a first pair of interdigitating stretching rollers to stretch activate at a first portion of the web and subsequently directing the web through a second pair of interdigitating stretching rollers to stretch activate a second portion of the non-activated strands within the web.  
     
     
         9 . The method according to  claim 1 , wherein the incrementally stretching the web further comprises impinging fluid onto the surface of the web.  
     
     
         10 . The method according to  claim 9 , wherein the fluid is either water or air.  
     
     
         11 . The method according to  claim 1 , wherein the first polymer component comprises an elastomeric polyurethane, elastomeric polyethylene, elastomeric polypropylene, styrene block copolymers or blends thereof, and the second polymer component comprises a polyolefin that is less elastic than the first component.  
     
     
         12 . The method according to  claim 10  wherein the second polymer component is polypropylene, polyethylene, or a blend thereof.  
     
     
         13 . The method according to  claim 2 , wherein the melt spinning comprises arranging the first and second polymer components in the strand cross-section to form a sheath/core configuration, and wherein the step of incrementally stretching includes forming corrugations in both the sheath and the core of the strands.  
     
     
         14 . The method according to  claim 2 , wherein the melt spinning comprises arranging the first and second polymer components in the strand cross-section to form the polymer components in a segmented pie configuration, and wherein the step of incrementally stretching includes either splitting the first and second polymer components apart from one another or forming serpentines or other non-linear, random textures of the less elastic components down the length of the strand.  
     
     
         15 . The method according-to  claim 2 , wherein the melt spinning comprises arranging the first and second polymer components in the strand cross-section to form polymer components in a tipped multilobal configuration, and wherein the step of incrementally stretching includes either splitting the first and second polymer components apart from one another or forming crimps down the length of the strand.  
     
     
         16 . The method according to  claim 1 , wherein at least a portion of the multicomponent strands has a sheath/core configuration.  
     
     
         17 .- 30 . (canceled)