Electrolytic copper foil, and negative electrode for lithium ion secondary battery, lithium ion secondary battery, copper clad laminated board and printed wiring board using the electrolytic copper foil

摘要

The tensile strength measured using each cut copper foil obtained by cutting the electrolytic copper foil from one end in the width direction to the other at 100 mm intervals satisfies the following requirements (I) to (III). -Requirement (I): The average value of the tensile strength of each of the cut copper foils in the normal state is 400 MPa or more and 650 MPa or less. -Requirement (II): The dispersion σ ² of the tensile strength of each of the cut copper foils in a normal state is 18 [MPa] ² or less. -Requirement (III): The average value of the tensile strength of each of the cut copper foils in a state after being heat-treated at 150°C for 1 hour is 350 MPa or more.