Ingredient for secondary cell separator coating material, secondary cell separator coating material, secondary cell separator, method for producing secondary cell separator, and secondary cell

An ingredient for a secondary cell separator coating material comprising:

• a water-soluble polymer having a repeating unit derived from methacrylamide and a repeating unit derived from a carboxy group-containing vinyl monomer without having a repeating unit derived from acrylamide, wherein
• the carboxy group-containing vinyl monomer is methacrylic acid;
• a content ratio of the repeating unit derived from the methacrylamide is more than 80% by mass and 97% by mass or less, and
• a content ratio of the repeating unit derived from the carboxy group-containing vinyl monomer is 3% by mass or more and 10% by mass or less with respect to the total amount of the water-soluble polymer;
• a weight average molecular weight of the water-soluble polymer is 20000 or more and 90000 or less;
• and
• a glass transition temperature of the water-soluble polymer is 200° C. or more.