Method for making polyimides

Abstract

A method is provided for making polyimides resulting from aromatic organic dianhydride and organic diamine interaction in the presence of an alkali metal salt of an oxygenated phosphorus compound.

What I claim as new and desire to secure by Letters Patent of the United States is: 
     
       1. A method for making polyimides which comprises (1) effecting reaction between a C.sub.(6-30) aromatic organic dianhydride and a C.sub.(2-20) organic diamine in the presence of an effective amount of an alkali metal salt of an oxygenated phosphorus compound, selected from the group consisting of orthophosphates, dihydrogen orthophosphates, hypophosphates, pyrophosphates, metaphosphates, orthophosphites, .[.and.]. arylphosphonates and .Iadd.arylphosphinates, .Iaddend.and   (2) recovering the resulting polyetherimide from the mixture of (1).   
     
     
       2. A method in accordance with claim 1 where the aromatic organic dianhydride has the formula, ##STR6## where R is a divalent aromatic organic radical having from 6-13 carbon atoms. 
     
     
       3. A method in accordance with claim 1, where the organic diamine has the formula,   H.sub.2 NR.sup.1 NH.sub.2,     where R 1  is a divalent organic radical selected from R radicals, alkylene radicals having from 2-20 carbon radicals, cyclo alkylene radicals and C.sub.(2-8) alkylene terminated polydiorganosiloxane radicals.   
     
     
       4. A method in accordance with claim 1, where the reaction is effected in the presence of organic solvent. 
     
     
       5. A method in accordance with claim 1, where the reaction is effected under melt conditions. 
     
     
       6. A method in accordance with claim 2, where the organic dianhydride has the formula, ##STR7## 
     
     
       7. A method in accordance with claim 3, where the organic diamine is meta-phenylenediamine. 
     
     
       8. A method in accordance with claim 3, where the organic diamine is para-phenylenediamine. 
     
     
       9. A method in accordance with claim 1, where the alkali metal salt is monosodium hypophosphite. 
     
     
       10. A method in accordance with claim 1, where the alkali metal salt is sodium phenylphosphite. 
     
     
       11. A method in accordance with claim 1, where the alkali metal salt is potassium phenylphosphite. .Iadd.12. A method in accordance with claim 1, where the alkali metal salt is potassium phenylphosphinate. .Iaddend. .Iadd.13. A method in accordance with claim 1, where the alkali metal salt is sodium phenylphosphinate. .Iaddend.