Nonwoven webs manufactured from additive-loaded multicomponent filaments

Abstract

Multicomponent filaments for manufacturing a hydrophilic nonwoven web in which each filament has a sheath and a core enclosed within the sheath that includes a concentration of an additive, such as a surfactant. Additive removed from an external surface of the sheath is replaced by additive migrating outwardly from the sheath. Additive migrating outwardly from the core into the sheath, which initially either includes a smaller additive concentration than the core or lacks additive, serves to replenish additive transferred from the sheath to the external surface.

1 . A nonwoven web comprising a plurality of multicomponent filaments, each of the multicomponent filaments comprising: 
 a sheath region including a first melt-processable polymer; and    a core region encased within said sheath region, said core region including a second melt-processable polymer and a first additive distributed at a first concentration in said second melt-processable polymer, said first additive migrating outwardly from said core region into said sheath region.    
   
   
       2 . The nonwoven web of  claim 1  wherein said first melt-processable polymer includes a second concentration of said first additive, said second concentration being less than said first concentration to produce a concentration gradient.  
   
   
       3 . The nonwoven web of  claim 2  wherein said first concentration of said first additive ranges from about 5% by weight to about 10% by weight and said second concentration of said first additive is less than about 3% by weight.  
   
   
       4 . The nonwoven web of  claim 1  wherein said first melt-processable polymer includes a second concentration of a second additive differing in chemical composition from said first additive.  
   
   
       5 . The nonwoven web of  claim 1  wherein said first concentration of said first additive ranges from about 5% by weight to about 10% by weight.  
   
   
       6 . The nonwoven web of  claim 1  wherein said first additive is a surfactant selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a non-ionic surfactant.  
   
   
       7 . The nonwoven web of  claim 1  wherein said sheath region and said core region are concentrically arranged.  
   
   
       8 . The nonwoven web of  claim 1  wherein said core region has an eccentric arrangement with said sheath region.  
   
   
       9 . The multicomponent filament of  claim 1  further comprising a plurality of core regions within said sheath region, at least one of said core regions including said first additive.  
   
   
       10 . The multicomponent filament of  claim 1  wherein said sheath region has an external surface and a portion of at least said first additive is chemically active at said external surface, after outward migration has occurred.  
   
   
       11 . A method of manufacturing a nonwoven web, comprising: 
 heating a first thermoplastic polymer to a flowable state;    heating a second thermoplastic polymer to a flowable state;    adding a first concentration of a first additive to the first thermoplastic polymer;    combining the first and second thermoplastic polymers to form a plurality of multicomponent filaments each having a sheath region including the second thermoplastic polymer and a core region including the first thermoplastic polymer and the first additive; and    collecting the plurality of multicomponent filaments to form a nonwoven web.    
   
   
       12 . The method of  claim 11  further comprising: 
 adding a second concentration of the first additive to the sheath region, the second concentration being smaller than the first concentration.    
   
   
       13 . The method of  claim 11  further comprising: 
 adding a second concentration of a second additive to the sheath region.