Apparatus and methods for producing split spunbond filaments

Abstract

A spunbonding apparatus capable of producing multicomponent spunbond filaments. The spunbonding apparatus includes a spunbonding apparatus comprises a spinneret discharging multicomponent filaments and a filament-drawing device applying a first force that is effective to attenuate the filaments. A force applicator stationed between the spinneret and the filament-drawing device is operative for applying a second force to the filaments that promotes filament splitting. Splitting may occur before the filaments enter the filament-drawing device, within the filament-drawing device, and/or after discharge from the filament-drawing device.

1 . A spunbonding apparatus comprising: 
 a spinneret adapted to discharge a plurality of multicomponent filaments that move in a downwardly direction away from said spinneret, each of the multicomponent filaments having at least two polymer regions;    a filament-drawing device positioned below said spinneret, said filament-drawing device adapted to pneumatically attenuate the multicomponent filaments;    a force applicator directing an air stream impinging the multicomponent filaments between said spinneret and said filament-drawing device, said air stream effective to divide at least some of the multicomponent filaments into the at least two polymer regions to form smaller filaments; and    a collector for collecting the smaller filaments.    
   
   
       2 . The spunbonding apparatus of  claim 1  wherein said force applicator includes an air knife directing said air stream at an impingement angle greater than 0° and less than 180° relative to the multicomponent filaments.  
   
   
       3 . The spunbonding apparatus of  claim 1  further comprising: 
 a first driven roller contacting the multicomponent filaments; and    a second driven roller spaced from said first driven roller, said second driven roller contacting the multicomponent filaments, and said air stream impinging the multicomponent filaments between said first driven roller and said second driven roller.    
   
   
       4 . The spunbonding apparatus of  claim 3  wherein said force applicator includes an air knife directing said air stream at the multicomponent filaments between said first driven roller and said second driven roller.  
   
   
       5 . The spunbonding apparatus of  claim 4  wherein said air stream intersects the multicomponent filaments at an impingement angle greater than 0° and less than 180° relative to the multicomponent filaments between said first driven roller and said second driven roller.  
   
   
       6 . A spunbonding apparatus comprising: 
 a spinneret adapted to discharge a plurality of multicomponent filaments that move in a downwardly direction away from said spinneret, each of the multicomponent filaments having at least two polymer regions;    a filament-drawing device positioned below said spinneret, said filament-drawing device adapted to pneumatically attenuate the multicomponent filaments;    a force applicator including a first roller contacting the plurality of multicomponent filaments between said spinneret and said filament-drawing device, said first roller effective to divide at least some of the multicomponent filaments into the at least two polymer regions to form smaller filaments; and    a collector for collecting the smaller filaments.    
   
   
       7 . The spunbonding apparatus of  claim 6  wherein said first roller is driven, and said force applicator further includes a second roller spaced from said first driven roller, said second roller being driven and contacting the multicomponent filaments.  
   
   
       8 . The spunbonding apparatus of  claim 7  wherein said first roller is separated from said second roller in a direction perpendicular to the downwardly direction in which the multicomponent filaments are moving.  
   
   
       9 . The spunbonding apparatus of  claim 7  wherein said first roller is separated from said second roller in a direction parallel to the downwardly direction in which the multicomponent filaments are moving.  
   
   
       10 . A method of forming a spunbond nonwoven web, comprising: 
 forming a plurality of multicomponent filaments each having at least two polymer regions;    pneumatically attenuating the multicomponent filaments;    applying a dividing force to the moving plurality of multicomponent filaments effective for dividing the at least two polymer regions of at least some of the filaments to provide smaller filaments; and    collecting the smaller filaments to form the spunbond nonwoven web.    
   
   
       11 . The method of  claim 10  wherein applying the dividing force further comprises: 
 acting with the second force on the moving plurality of multicomponent filaments along a line perpendicular to the first force.    
   
   
       12 . The method of  claim 10  wherein the plurality of multicomponent filaments travel in a downward direction, and applying the dividing force further comprises: 
 directing an air stream toward the multicomponent filaments at an angle that is less than 180° and greater than 0° relative to the downward direction.    
   
   
       13 . The method of  claim 10  wherein applying the dividing force further comprises: 
 intersecting the multicomponent filaments with at least one roller to apply the dividing force.    
   
   
       14 . The method of  claim 10  wherein applying the dividing force further comprises: 
 intersecting the multicomponent filaments with a plurality of rollers rotating at different angular velocities to apply the dividing force.    
   
   
       15 . The method of  claim 10  wherein applying the dividing force further comprises: 
 intersecting the multicomponent filaments with a plurality of rollers rotating at a uniform angular velocity to apply the dividing force.    
   
   
       16 . The method of  claim 10  wherein the filaments are substantially attenuated before the dividing force is applied.  
   
   
       17 . The method of  claim 16  further comprising: 
 quenching the filaments with a flow of cooling air before the dividing force is applied.