Tetrafluoroethylene, isobutylene, carboxylic copolymers

Claim 1

A COPOLYMER COMPRISING IN COPOLYMERIZED FORM (A) 53-67 PERCENT BY WEIGHT TETRAFLUOROETHYLENE; (B) 32-44 PERCENT BY WEIGHT ISOBUTYLENE; AND (C) 0.01-12 PERCENT BY WEIGHT OF A POLYMERIZABLE COMPOUND SELECTED FROM THE CLASS CONSISTING OF: (1) AN UNSATURATED ALIPHATIC CARBOXYLIC ACID OF AT MOST 10 CARBON ATOMS WHEREIN THE UNSATURATION IS MONOETHYLENIC AND WHICH CAN CONTAIN UP TO ONE SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE AND CARBOXYL; (2) AN UNSATURATED ALICYCLIC HYDROCARBONCARBOXYLIC ACID OF AT MOST 10 CARBON ATOMS WHEREIN THE UNSATURATION IS MONOETHYLENIC; (3) A TERTIARY LOWER ALKYL ESTER OF CLASSES (1) AND (2) WHEREIN THE TOTAL CARBON ATOM CONTENT IS AT MOST 10 ATOMS; (4) A CYCLIC ANHYDRIDE OF AN UNSATURATED HYDROCARBONDICARBOXYLIC ACID OF AT MOST 10 CARBON ATOMS WHEREIN THE UNSATURATION IS MONOETHYLENIC; (5) AN UNSATURATED ALIPHATIC PHOSPHONIC ACID OF AT MOST 10 CARBON ATOMS WHEREIN THE UNSATURATION IS MONOETHYLENIC AND WHICH CAN CONTAIN UP TO ONE SUBSTITUENT SELECTED FROM THE GROUP CONSISTING OF CHLORINE AND BROMINE; (6) A MONO- ESTHER OF CLASS (5), AND (7) A DI-ESTER OF CLASS (5), WHEREIN THE ESTER MOIETIES OF CLASSES (6) AND (7) ARE OF THE GROUP CONSISTING OF LOWER ALKYL, BENZYL AND PHENYL AND CAN EACH CONTAIN SUBSTITUENTS SELECTED FROM THE GROUP CONSISTING OF CHLORINE AND BROMINE, THE TOTAL CARBON CONTENT BEING NOT MORE THAN 18 CARBON ATOMS.