SEPARATOR, SECONDARY BATTERY, ELECTROCHEMICAL DEVICE, AND ELECTRIC DEVICE

A separator includes a base film and an organic coating disposed on one surface of the base film. The organic coating contains a first polymer and a second polymer. A melting point T of the first polymer satisfies 60° C.≤T≤100° C., and a swelling degree D of the second polymer during placement in an electrolyte solution at 60° C. for 24 h satisfies D≤30%.