CROSSLINKED IONICALLY CONDUCTING RESIN, AND IONICALLY CONDUCTING POLYMER MEMBRANES, BINDERS AND FUEL CELLS, MADE BY USING THE RESIN

The crosslinkable ion conductive resin comprises a crosslinkable polyether ketone having a repeating unit represented by the formula (1), wherein Ar 1 and Ar 2 have two or more aromatic rings, at least two of which are bivalent groups linked by an alkylene bond; hydrogen in an aromatic ring may be substituted with halogen, an alkyl group having 1 to 10 carbon atoms, a halogenated hydrocarbon group or a protonic acid group; the above alkylene is a group having 1 to 10 carbon atoms in which carbon atoms linked to an aromatic ring of at least one side are bonded to at least one hydrogen; X and Y respectively represent a protonic acid group selected from a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a sulfonimide group and an alkyl sulfonate group having 1 to 10 carbon atoms, or a group of a metal salt thereof; x and y are an integer of 0 to 4; x+y is at least not less than 1; and a and b are an integer of not less than 1. The polymer membrane and the binder using the aforementioned resin are suitable for use in a fuel cell.