Patent ID: 8809451

Claim:
A polymer obtained by polycondensation of a fluorinated dicarboxylic acid derivative of the general formula (M-1) or an acid anhydride of the fluorinated dicarboxylic acid with a polyfunctional compound having two to four reactive groups corresponding in reactivity to carbonyl moieties of the fluorinated dicarboxylic acid derivative or acid anhydride: AOCF 2 C-Q-CF 2 COA′ (M-1) where Q represents a divalent organic group having a substituted or unsubstituted aromatic ring; each of CF 2 COA and CF 2 COA′ is bonded to a carbon atom of the aromatic ring; wherein the aromatic ring may be substituted with one or more of the following a fluorine atom, a chlorine atom, a hydroxyl group, an amino group, a nitro group, a cyano group, a hydroxycarbonyl group, a C 1 -C 6 straight, branched or cyclic alkyl group (whose hydrogen atom may be substituted with a hydroxyl group or a fluorine atom), a C 1 -C 6 straight, branched or cyclic alkoxy group or a C 1 -C 6 straight, branched or cyclic alkoxycarbonyl group; A and A′ each independently represent a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a C 1 -C 6 straight, branched or cyclic alkoxy group or a C 6 -C 10 aryloxy group; and each of A and A′ may form an active ester moiety together with a CO group in the formula.