Process for forming a high loft, nonwoven web exhibiting excellent recovery

Abstract

A process for forming a high loft, nonwoven web exhibiting excellent recovery.

We claim: 
     
         1 . A process for forming a high loft, nonwoven web, comprising the steps of:
 a) introducing a molten polymer to a die having a plurality of nozzles;   b) emitting said molten polymer through said plurality of nozzles to form a plurality of filaments;   c) using air streams to facilitate movement and drawing of said plurality of filaments;   d) directing said filaments towards a pair of moving surfaces located at a distance of from between about 10 cm to about 150 cm from said plurality of nozzles, and said pair of moving surfaces forming a convergent passage having an entry and an exit;   e) depositing said plurality of filaments into said entry of said convergent passage;   f) routing said plurality of filaments through said convergent passage from said entry to said exit and between said pair of moving surfaces in a machine direction to form a 3-dimensional structure with said filaments transformed into fibers oriented in the x, y and z directions; and   g) bonding said 3-dimensional structure to form a high loft, nonwoven web having a thickness of less than about 250 millimeters and a basis weight ranging from between about 50 g/m 2  to about 3,000 g/m 2 , and a vertical cross-section of said high loft, nonwoven web, when taken parallel to said machine direction, exhibiting a plurality of snugly stacked, approximately V, U or C-shaped structures, with each V, U or C-shaped structure having an apex facing in said machine direction, and said high loft, nonwoven web having a recovery value ranging from between about 20% to about 99% after being compressed under a pressure of 0.25 psi for a time period of 30 minutes.   
     
     
         2 . The process of  claim 1  wherein said 3-dimensional structure is bonded using thermal bonding, through air bonding, oven bonding, chemical bonding, wet bonding, mechanical bonding or hydro-mechanical bonding. 
     
     
         3 . The process of  claim 1  further comprising adding an additive to said high loft, nonwoven web downstream of said bonding. 
     
     
         4 . The process of  claim 4  wherein said additive is a superabsorbent. 
     
     
         5 . The process of  claim 1  further comprising spraying an additive onto said high loft, nonwoven web downstream of said bonding. 
     
     
         6 . The process of  claim 5  wherein said additive is a fire retardant. 
     
     
         7 . The process of  claim 1  further comprising drying said high loft, nonwoven web downstream of said bonding. 
     
     
         8 . The process of  claim 1  further comprising cooling said high loft, nonwoven web downstream of said bonding. 
     
     
         9 . The process of  claim 8  wherein said high loft, nonwoven web is cooled to room temperature. 
     
     
         10 . A process for forming a high loft, nonwoven web, comprising the steps of:
 a) introducing a molten polymer to a die having a plurality of nozzles;   b) emitting said molten polymer through said plurality of nozzles to form a plurality of filaments;   c) using air streams to facilitate movement and drawing of said plurality of filaments;   d) directing said filaments towards first and second rotatable drums having a nip formed therebetween, said first and second rotatable drums located at a distance of from between about 10 cm to about 150 cm from said plurality of nozzles, and said first and second rotatable drums forming a convergent passage having an entry and an exit;   e) depositing said plurality of filaments into said entry of said convergent passage;   f) routing said plurality of filaments through said convergent passage from said entry to said exit and between said nip formed by said first and second rotatable drums in a machine direction to form a 3-dimensional structure with said filaments transformed into fibers oriented in the x, y and z directions; and   g) thermally bonding said 3-dimensional structure to form a high loft, nonwoven web having a thickness of less than about 250 millimeters and a basis weight ranging from between about 50 g/m 2  to about 3,000 g/m 2 , and a vertical cross-section of said high loft, nonwoven web, when taken parallel to said machine direction, exhibiting a plurality of snugly stacked, approximately V, U or C-shaped structures, with each V, U or C-shaped structure having an apex facing in said machine direction, and said high loft, nonwoven web having a recovery value ranging from between about 30% to about 95% after being compressed under a pressure of 0.25 psi for a time period of 30 minutes.   
     
     
         11 . The process of  claim 10  further comprising adding an additive to said high loft, nonwoven web downstream of said bonding. 
     
     
         12 . The process of  claim 10  further comprising immersing said high loft, nonwoven web in a liquid solution containing an additive. 
     
     
         13 . The process of  claim 10  further comprising spraying an additive onto said high loft, nonwoven web downstream of said bonding. 
     
     
         14 . The process of  claim 10  further comprising drying said high loft, nonwoven web downstream of said bonding. 
     
     
         15 . The process of  claim 10  further comprising cooling said high loft, nonwoven web downstream of said bonding to room temperature. 
     
     
         16 . A process for forming a high loft, nonwoven web, comprising the steps of:
 a) introducing a molten polymer to a die having a plurality of nozzles;   b) emitting said molten polymer through said plurality of nozzles to form a plurality of filaments;   c) using air streams to facilitate movement and drawing of said plurality of filaments;   d) directing said filaments towards first and second conveyor belts having an opening formed therebetween, said first and second conveyor belts located at a distance of from between about 10 cm to about 150 cm from said plurality of nozzles, and said first and second conveyor belts forming a convergent passage having an entry and an exit;   e) depositing said plurality of filaments into said entry of said convergent passage;   f) routing said plurality of filaments through said convergent passage from said entry to said exit and between said opening formed by said first and second conveyor belts in a machine direction to form a 3-dimensional structure with said filaments transformed into fibers oriented in the x, y and z directions; and   g) thermally bonding said 3-dimensional structure to form a high loft, nonwoven web having a thickness of less than about 250 millimeters and a basis weight ranging from between about 50 g/m 2  to about 3,000 g/m 2 , and a vertical cross-section of said high loft, nonwoven web, when taken parallel to said machine direction, exhibiting a plurality of snugly stacked, approximately V, U or C-shaped structures, with each V, U or C-shaped structure having an apex facing in said machine direction, and said high loft, nonwoven web having a recovery value ranging from between about 40% to about 90% after being compressed under a pressure of 0.25 psi for a time period of 30 minutes.   
     
     
         17 . The process of  claim 16  further comprising adding an additive to said high loft, nonwoven web downstream of said bonding. 
     
     
         18 . The process of  claim 16  further comprising spraying an additive onto said high loft, nonwoven web downstream of said bonding. 
     
     
         19 . The process of  claim 16  further comprising drying said high loft, nonwoven web downstream of said bonding. 
     
     
         20 . The process of  claim 16  further comprising cooling said high loft, nonwoven web downstream of said bonding.