COMPOSITION FOR LITHIUM ION SECONDARY BATTERY SEPARATOR, TWO-PART COMPOSITION FOR LITHIUM ION SECONDARY BATTERY SEPARATOR, METHOD OF PRODUCING SEPARATOR FOR LITHIUM ION SECONDARY BATTERY, AND METHOD OF PRODUCING LITHIUM ION SECONDARY BATTERY

Provided are a composition for a lithium ion secondary battery separator containing: a liquid medium; and 40 mass % or less of a first compound including a function-displaying functional group and having a molecular weight of 50,000 or less, and having a surface tension of 15 mN/m to 30 mN/m, and a two-part composition for a lithium ion secondary battery separator including: a first liquid containing a first compound and first liquid medium; and a second liquid containing a second compound and second liquid medium, wherein the first compound includes a function-displaying functional group and has a molecular weight of 50,000 or less, the second compound is reactive with the first compound and has a molecular weight of 50,000 or less, and the first and second liquids each contain the corresponding compound in a proportion of 40 mass % or less and have a surface tension of 15 mN/m to 30 mN/m.