High temperature paper containing aramid component

Abstract

Provided is a paper structure comprised of cellulose pulp fiber, a polymeric binder, and an aramid component comprised of aramid fiber and/or fibrid. The paper structure can also comprise multiple layers of different composition, but at least one layer must comprise the aramid component and polymeric binder.

What is claimed is:  
     
         1 . A paper structure comprised of cellulosic pulp fiber, a polymeric binder, and an aramid component comprised of aramid fiber and/or aramid fibrid.  
     
     
         2 . A paper structure comprised of two outside layers and at least one inside layer, with the two outside layers being comprised of substantially cellulosic pulp fiber, and the inside layer being the paper structure of  claim 1 .  
     
     
         3 . The paper structure of  claim 1 , wherein the polymeric binder is comprised of polyvinyl alcohol.  
     
     
         4 . The paper structure of  claim 1 , wherein the aramid component is comprised of a mixture of aramid fiber and aramid fibrid.  
     
     
         5 . The paper structure of  claim 2 , wherein the polymeric binder is comprised of polyvinyl alcohol.  
     
     
         6 . The paper structure of  claim 2 , wherein the aramid component is comprised of a mixture of aramid fiber and aramid fibrid.  
     
     
         7 . The paper structure of  claim 2 , wherein the outside layers further comprise a minor amount of synthetic fiber.  
     
     
         8 . A paper structure comprised of two outside layers comprised of substantially cellulosic pulp fiber, and at least two inside layers comprised of cellulosic pulp, a polymeric binder and an aramid component comprised of aramid fiber and/or aramid fibrid.  
     
     
         9 . A process for making the paper structure of  claim 1 , which comprises utilizing a cylinder machine with at least three different cylinders, the process comprising feeding a stock composition comprised substantially of cellulosic pulp fiber to the cylinders corresponding to the outer layers, such that the two outside layers of the resulting paper structure are comprised of substantially cellulosic pulp fibers, and 
 with the other cylinder being fed a stock solution comprised of cellulosic pulp fiber, aramid fiber, aramid fibrid, and a polymeric binder, such that the inner layer of the paper structure is comprised of the cellulosic pulp fiber, aramid fiber, aramid fibrid, and polymeric binder.    
     
     
         10 . The process of  claim 9 , wherein five cylinders are employed, with the cylinders corresponding to the outside layers of the paper structure being fed stock solutions comprised substantially of cellulosic pulp fiber, and the three inner cylinders being fed solutions comprised of cellulosic pulp fiber, aramid fiber, aramid fibrid, and a polymeric binder.  
     
     
         11 . The process of  claim 9 , wherein the polymeric binder in the stock solution fed to the cylinder corresponding to the inner layer is comprised of polyvinyl alcohol.  
     
     
         12 . A high temperature transformer paper comprised of the paper structure of  claim 1 .  
     
     
         13 . A high temperature transformer paper comprised of the paper structure of  claim 2 .  
     
     
         14 . A high temperature transformer paper comprised of the paper structure of  claim 3 .  
     
     
         15 . A transformer comprised of the paper of  claim 1 .  
     
     
         16 . A transformer comprised of the paper of  claim 2 .  
     
     
         17 . A transformer comprised of the paper of  claim 4 .  
     
     
         18 . A transformer comprised of the paper of  claim 8.