Paper comprising polybenzazole or precursor thereof

Abstract

The invention relates to a paper comprising at least one of a fiber, pulp, fibril, floc, and fibrid having a polybenzazole structure with a repeating unit of formula (I) and/or (II) or its precursor structure with a repeating unit of formula (III): wherein Ar 1 and Ar 2 are independently a para or meta aromatic group having 4 to 12 carbon atoms, X and Y are the same or different and selected from O, S, and NH; and n is 0 or 1, and wherein the paper is free or essentially free of non-extractable phosphorus compound. The paper is particularly suitable for making an electrical insulation material, a honeycomb structure, or a constructive material.

1 . A paper comprising at least one of a fiber, pulp, fibril, floc, and fibrid having a polybenzazole structure with a repeating unit of formula (I) and/or (II) 
       
         
           
           
               
               
           
         
         or its precursor structure with a repeating unit of formula (III): 
       
       
         
           
           
               
               
           
         
         wherein Ar 1  and Ar 2  are independently a para or meta aromatic group having 4 to 12 carbon atoms, X and Y are the same or different and selected from O, S, and NH; and n is 0 or 1, and wherein the paper is free or essentially free of non-extractable phosphorus compound. 
       
     
     
         2 . The paper of  claim 1  obtainable by polymerizing about equimolar amounts of monomers having the formula ClOOC—Ar 1 —COOCl and 
       
         
           
           
               
               
           
         
         wherein Ar 1  and Ar 2  are independently a para or meta aromatic group having 4 to 12 carbon atoms, X and Y are the same or different and selected from O, S, and NH; and n is 0 or 1, to the precursor structure containing the repeating unit of formula (III), 
       
       
         
           
           
               
               
           
         
         wherein Ar 1 , Ar 2 , X, Y and n have the previously given meanings, optionally followed by cyclising the precursor structure to the polybenzazole structure with the repeating unit of formula (I) and/or (II) 
       
       
         
           
           
               
               
           
         
       
       wherein Ar 1 , Ar 2 , X, and Y have the previously given meanings, in a fluid which is free or essentially free from phosphoric acid. 
     
     
         3 . The paper of  claim 1  wherein at least part of XH and/or YH is functionalized. 
     
     
         4 . The paper of  claim 1  having a grammage from 1 to 16 g/m 2 . 
     
     
         5 . The paper of  claim 1  comprising a mixture of at least one of fiber, pulp, fibril, floe, and fibrid having the polybenzazole structure of formula (I) and/or (II), or the polybenzazole precursor structure of formula (III), and PPTA fibrid. 
     
     
         6 . A method for making the paper of  claim 1  comprising polymerizing about equimolar amounts of monomers having the formula ClOOC—Ar 1 —COOCl and 
       
         
           
           
               
               
           
         
         wherein Ar 1  and Ar 2  are independently a para or meta aromatic group having 4 to 12 carbon atoms, X and Y are the same or different and selected from O, S, and NH; and n is 0 or 1, to a precursor structure containing the repeating unit expressed by formula (III) 
       
       
         
           
           
               
               
           
         
         wherein Ar 1 , Ar 2 , X, Y and n have the previously given meanings, optionally followed by cyclising under heating in an inert atmosphere the precursor structure to a polybenzazole structure having a repeating unit of formula (I) and/or (II) 
       
       
         
           
           
               
               
           
         
         wherein Ar 1 , Ar 2 , X, and Y have the previously given meanings, in a fluid which is free or essentially free from phosphoric acid, followed by making a fiber, pulp, fibril, floc, or fibrid from the precursor or from the polybenzazole structure, followed by making the paper thereof by a conventional papermaking process optionally followed by one or more of a calendering step, heating step, drying step, and functionalization step. 
       
     
     
         7 . The method according to  claim 6  wherein at least part of the XH and/or YH groups of Ar 2  are functionalized by treating the monomer and/or the precursor structure and/or the polybenzazoe structure with a functionalizing agent. 
     
     
         8 . A method for making the paper of  claim 1  comprising polymerizing about equimolar amounts of monomers having the formula ClOOC—Ar 1 —COOCl and 
       
         
           
           
               
               
           
         
         wherein Ar 1  and Ar 2  are independently a para or meta aromatic group having 4 to 12 carbon atoms, X and Y are the same or different and selected from O, S, and NH; and n is 0 or 1, to a precursor having the repeating unit of formula (III) 
       
       
         
           
           
               
               
           
         
         wherein Ar 1 , Ar 2 , X, Y and n have the previously given meanings, in a fluid which is free or essentially free from phosphoric acid, followed by making a fiber, pulp, fibril, floe, or fibril from the precursor, followed by making the paper thereof in a conventional papermaking process, optionally followed by one or more of a calendering step, heating step, drying step, and functionalization step. 
       
     
     
         9 . The method according to  claim 7  wherein the paper obtained is heated under an inert atmosphere at a temperature allowing cyclization of the polybenzazole precursor having formula (III) to the polybenzazole comprising the structure of formula (I) and/or (II). 
     
     
         10 . The method according to  claim 8  wherein at least part of the XH and/or YH groups of Ar 2  are functionalized by treating the monomer and/or the precursor structure and/or the polybenzazoe structure with a functionalizing agent. 
     
     
         11 . A method for making the paper of  claim 6  comprising applying a conventional papermaking process further using at least one of fiber, pulp, fibril, floc, and fibrid having the structure IV 
       
         
           
           
               
               
           
         
         wherein the Ar 1  moieties have independently the previously given meaning. 
       
     
     
         12 . An electrical insulation material comprising the paper of  claim 1 . 
     
     
         13 . An electrical insulation material, a honeycomb structure, or a constructive material comprising as a component the paper of  claim 1 .