BINDER COMPOSITION FOR NONAQUEOUS SECONDARY BATTERY ELECTRODES, SLURRY COMPOSITION FOR NONAQUEOUS SECONDARY BATTERY ELECTRODES, ELECTRODE FOR NONAQUEOUS SECONDARY BATTERIES, AND NONAQUEOUS SECONDARY BATTERY

A binder composition for a non-aqueous secondary battery electrode contains a polymer X dissolved in water. The polymer X is water-soluble and has a total proportional content of a conjugated diene monomer unit and an alkylene structural unit of not less than 25.0 mass% and not more than 58.0 mass%.