BINDER FOR SECONDARY BATTERY, BINDER RESIN COMPOSITION FOR SECONDARY BATTERY, ELECTRODE FOR SECONDARY BATTERY, AND SECONDARY BATTERY

The present application relates to a binder for a secondary battery. The binder includes a first copolymer unit including a carboxyl group-containing acrylic monomer and at least one of an acrylic acid derivative monomer and a substituted or unsubstituted styrene and a second copolymer unit including a residue of a polymer azo initiator. A mass ratio of the second copolymer unit relative to a total mass of the first copolymer unit and the second copolymer unit is 10 mass % to 40 mass %.