Patent ID: 7939600

Claim:
A binder for an electric double layer capacitor electrode, comprising a polymer: wherein the polymer comprises a monomeric unit obtained by polymerizing a compound represented by the following formula (1) in a total amount of 60% or more by weight: CH 2 ═CR 1 —COOR 2 (1) in which R 1 represents a hydrogen atom or a methyl group and R 2 represents an alkyl group or a cycloalkyl group; wherein the polymer has a crosslinkable functional group which is a combination of an epoxy group and a sulfonic acid group or a salt thereof; and wherein the total amount of the monomer having the crosslinkable functional group is from 0.1 to 10% by weight in the whole of the monomers, whereby said polymer can give a polymer film having a tensile stress of 2 MPa or less when the film is elongated at the ratio of 100% and having the elongation at break of 450% or more.