Process and apparatus for making a sheet of aramid fibers using a foamed medium

Abstract

The present invention relates to a method for forming a non-woven fibrous web comprised of aramid fibers and aramid fibrid which comprises forming a foam furnish by agitating the fibers and fibrid in a foamed medium, and passing the foam furnish onto a screen and defoaming the furnish. In effectively agitating the aramid fibers in the foamed medium, the agitating means is mounted for displacement within the foamed medium and includes a convex leading surface facing in the direction of displacement. The leading surface includes upper and lower portions converging in the direction of displacement to form a generally convex leading surface and driving means for displacing the agitating means in the direction of displacement for dispersing and mutually separating the aramid fibers within the foamed medium.

1 - 21 . (canceled)  
     
     
         22 . A non-woven, fibrous web prepared by a method comprising: 
 (i) forming a foam furnish by agitating aramid fibers in a foamed medium, the furnish also containing aramid fibrid, with an apparatus comprising agitating means mounted for displacement within the foamed medium and including a leading surface facing in a direction of displacement, the leading surface including upper and lower portions converging in the direction of displacement to form a generally convex leading surface: and driving means for displacing the agitating means in the direction of displacement for dispersing and mutually separating the fibers within the foamed medium: and    (ii) passing the foam furnish onto a screen and defoaming the furnish to form the web with the web exhibiting substantially no fiber directionality.    
     
     
         23 . The non-woven web of  claim 22 , wherein the amount of fibrid comprises 30% or less by weight of the web.  
     
     
         24 . The non-woven web of  claim 22 , wherein the amount of fibrid comprises 25% or less by weight of the web.  
     
     
         25 . (canceled)  
     
     
         26 . (canceled)  
     
     
         27 . The non-woven web of  claim 22 , wherein the aramid fibers are comprised of fibers at least one inch in length.  
     
     
         28 . The non-woven web of  claim 22 , wherein the aramid fibers are comprised of fibers at least one and one-half inch in length.  
     
     
         29 . The non-woven web of  claim 22 , wherein the web is further comprised of synthetic and/or metal fibers.  
     
     
         30 . The non-woven web of  claim 22 , wherein the web is further comprised of cellulosic fibers.  
     
     
         31 . The non-woven web of  claim 22 , wherein the web is further comprised of inorganic fibers.