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US 3,939,109 AGranted
Polyamic-acids prepared from 3,3,4,4-benzhydrol tetracarboxylic dianhydride
AssigneeGulf Research & Development Company
InventorsWalter P. Barie, Jr., Anatoli Onopchenko, Johann G. D. Schulz
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Abstract
A novel polyamic acid intermediate composition in a polar, aprotic solvent and the corresponding fully condensed polyimide are prepared from 3,3',4,4'-benzhydrol tetracarboxylic dianhydride and a diamine having at least two carbon atoms such as bis(4-aminophenyl)ether.
Claims7
A polyamic acid having the general formula ##SPC4##
- where the carbonyl groups are independently in the 3-, 4- and 3'-, 4'- positions respectively, wherein n is greater than about 10 up to about 1000 and R is a divalent organic radical having at least two carbon atoms with each nitrogen atom chemically bonded to different carbon atoms of said R radical.
Dependencies are inferred from the claim text.