Wire enamel based on amide-imide hydantoin polymers

Abstract

Amide-imide-hydantoin polymers are prepared from trimellitic anhydride, a diisocyanate and reacting the isocyanate terminated amide-imide with a glycine derivative of the formula ##STR1## WHERE R is aromatic, R 1 are the same or different and are hydrogen or alkyl, R 2 is dialkylamino, alkoxy or aroxy and x is an integer from 2 to 4. A portion of the trimellitic anhydride can be replaced by a dicarboxylic acid, a dianhydride or a tribasic acid. The products are soluble in cresol type solvent.

What is claimed is: 
     
       1. An amide-imide-hydantoin polymer wherein the recurring hydantoin units are 5 to 95% of the total linkages and the amide groups are 20 to 80% of the total number of the amide and imide groups, the recurring hydantoin units having the formula: ##STR4## wherein the symbol Ar represents an aromatic hydrocarbon radical or an aromatic hydrocarbon radical carrying a substituent group selected from the class consisting of halo, nitro, alkyl, alkoxy, dialkylamino, acyl, carbalkoxy or cyano; the symbol Y represents .Iadd.the residue of the reaction product of trimellitic anhydride and a diisocyanate having the formula OCN-Z-NCO where Z represents .Iaddend.a radical as defined for Ar or is an alkylene radical of 4 to 10 carbon atoms, an oxyalkylene radical of 4 to 10 carbon atoms or a thioalkylene radical of 4 to 10 carbon atoms; the symbol R 1  represents hydrogen or an alkyl radical, and wherein the said hydantoin units are formed by reacting (A) a glycine derivative of the formula ##STR5## wherein R 2  is a dialkylamino, alkoxy or aryloxy radical and x is an integer from 2 to 4, with (B) a preformed amide-imide prepolymer having terminal isocyanate groups, said prepolymer having been prepared by reacting (1) trimellitic anhydride or (2) a mixture of trimellitic anhydride with a dicarboxylic acid or carboxylic acid dianhydride or tricarboxylic acid with (a) a diisocyanate, or (b) a diisocyanate and up to about 15 equivalent percent of an organic titanate.   
     
     
       2. A polymer according to claim 1 wherein 20 to 60% of the total linkages are recurring hydantoin units. 
     
     
       3. A polymer according to claim 1 wherein 30 to 95% of the total linkages are recurring hydantoin units. 
     
     
       4. A polymer according to claim 1 wherein 30 to 70% of the total number of amide and imide groups are amide groups. 
     
     
       5. A polymer according to claim 1 wherein the reaction between the trimellitic anhydride and the diisocyanate is carried out in the absence of solvent and a cresylic solvent of phenol is added as a solvent to the prepolymer thus formed and the glycine derivative is converted to hydantoin units in the presence of said added solvent and prepolymer. 
     
     
       6. A polymer according to claim 1 wherein Ar and Y are both hydrocarbon and the diisocyanate is an aromatic diisocyanate. 
     
     
       7. A polymer according to claim 6 prepared from reactants comprising (1) .[.0.95.]. .Iadd.0.85 .Iaddend.to 1.05 moles of diisocyanate, (2) 0.05 to 0.95 mole of glycine derivative, (3) 0.95 to 0.01 mole of trimellitic anhydride, (4) 0.0 to 0.3 mole of dicarboxylic acid, (5) 0.0 to 0.3 mole of carboxylic dianhydride and (6) 0.0 to 0.05 mole of tricarboxylic acid, (7) 0.0 to 0.06 mole of organic titanate, the total of (2), (3), (4), (5) and (6) being from 1.05 to 0.95 moles. 
     
     
       8. A polymer according to claim 7 wherein the trimellitic anhydride is 100% of the total of (3), (4), (5) and (6). 
     
     
       9. A polymer according to claim 7 wherein the trimellitic anhydride is 99.9-.[.9.60.]..Iadd.60.Iaddend.% of the total moles of (3), (4), (5) and (6). 
     
     
       10. A polymer according to claim 7 wherein the trimellitic anhydride is 60-100% of the total of (3), (4), (5) and (6). 
     
     
       11. A polymer according to claim 10 wherein the trimellitic anhydride is present in an amount of 0.05-0.6 mole. 
     
     
       12. A polymer according to claim 10 in which the amount of (6) is 0. 
     
     
       13. A polymer according to claim 10 wherein all R 1  groups are hydrogen. 
     
     
       14. A polymer according to claim 13 wherein the starting glycine derivative is methylene bis (N-phenylglycine lower alkyl ester). 
     
     
       15. A polymer according to claim 13 wherein Y and Ar are both methylene bis (phenyl). 
     
     
       16. A wire enamel composition containing the product of claim 2 in a solvent. 
     
     
       17. A product according to claim 16 wherein the solvent is a cresol solvent. 
     
     
       18. A product according to claim 17 wherein the solvent also includes an aromatic hydrocarbon. 
     
     
       19. A wire enamel composition containing the product of claim 1 in a solvent. 
     
     
       20. An electrical conductor coated with the product of claim 1. 
     
     
       21. The process of preparing the product of claim 1 comprising heating a glycine derivative of the formula ##STR6## with a preformed amide-imide prepolymer having terminal isocyanate groups. 
     
     
       22. A process according to claim 21 wherein there is included a small amount of an organic titanate as a reactant. 
     
     
       23. A product according to claim 1 wherein the polymer contains at least 30% of the total linkages as recurring hydantoin units and the polymer is modified by containing titanate linkages. 
     
     
       24. A process according to claim 21, including the steps of forming said preformed amide-imide prepolymer by (a) reacting the trimellitic anhydride and diisocyanate in the absence of a solvent, (b) adding a cresylic solvent or phenol as a solvent to the prepolymer thus formed and converting the glycine derivative to hydantoin in the presence of said added solvent and prepolymer. 
     
     
       25. A polymer according to claim 10 wherein the trimellitic anhydride is present in an amount of 0.4-0.5 mole.