Electroconductive aramid paper

Abstract

This invention relates to aramid papers, and a process for making such papers, the papers comprising 5 to 65 parts by weight aramid fiber, 30-90 parts by weight aramid fibrids, and 1-20 parts by weight of conductive filler, based on the total weight of the aramid fiber, fibrids, and filler; the papers having an apparent density of not more than 0.43 g/cm 3 and a tensile index not less than 60 Nm/g.

1 . Aramid paper comprising 5 to 65 parts by weight aramid fiber, 30-90 parts by weight aramid fibrids, and 1-20 parts by weight of conductive filler, based on the total weight of the aramid fiber, fibrids, and filler, the paper having an apparent density of not more than 0.43 g/cm 3  and a tensile index not less than 60 Nm/g.  
   
   
       2 . The aramid paper of  claim 1 , wherein the conductive filler is carbon fiber.  
   
   
       3 . The aramid paper of  claim 1 , wherein the aramid fiber is poly (metaphenylene isophtalamide) fiber.  
   
   
       4 . The aramid paper of  claim 2 , wherein the aramid fiber is poly (metaphenylene isophthalamide) fiber.  
   
   
       5 . A process for making aramid paper comprising the steps of: 
 a) forming an aqueous dispersion of 5 to 65 parts by weight aramid fiber, 30-90 parts by weight aramid fibrids, and 1-20 parts by weight of conductive filler, based on the total weight of the aramid fiber, fibrids, and filler,    b) blending the dispersion to form a slurry,    c) draining the aqueous liquid from the slurry to yield a wet paper composition,    d) drying the wet paper composition,    e) heat treating the paper at or above the glass transition temperature of the polymer in the aramid fibrids without consolidation of the paper.    
   
   
       6 . The process of  claim 5  wherein the water is drained from the second slurry via a screen or wire belt.