Abstract: The present invention provides a cation exchange resin, and a cation exchange membrane and an electrolyte membrane for a fuel cell using the same. The cation exchange resin comprises a divalent hydrophobic unit; and a divalent hydrophilic unit having divalent hydrophilic groups which are repeated via carbon-carbon bond. The divalent hydrophilic groups being composed of one aromatic ring, or being composed of a plurality of aromatic rings which are bonded to each other via a divalent hydrocarbon group, a divalent silicon-containing group, a divalent nitrogen-containing group, a divalent phosphorus-containing group, a divalent oxygen-containing group, a divalent sulfur-containing group, or carbon-carbon bond, and at least one of the aromatic rings having a cation exchange group; wherein the hydrophobic unit and the hydrophilic unit are bonded to each other via carbon-carbon bond.

Abstract: A cation exchange resin having improved chemical properties and mechanical properties, and a cation exchange membrane and an electrolyte membrane for a fuel cell using the same are provided. A cation exchange resin is used, the cation exchange resin comprising: a divalent hydrophobic unit; and a divalent hydrophilic unit having divalent hydrophilic groups which are repeated via carbon-carbon bond, the divalent hydrophilic groups being composed of one aromatic ring, or being composed of a plurality of aromatic rings which are bonded to each other via a divalent hydrocarbon group, a divalent silicon-containing group, a divalent nitrogen-containing group, a divalent phosphorus-containing group, a divalent oxygen-containing group, a divalent sulfur-containing group, or carbon-carbon bond, at least one of the aromatic rings having a cation exchange group; wherein the hydrophobic unit and the hydrophilic unit are bonded to each other via carbon-carbon bond.