Novel Polyvinyl Sulfonic Acid, Production Method Thereof, and Use Thereof

摘要

The present invention relates to polyvinyl sulfonic acid comprising a vinyl sulfonic acid unit represented by a specific general formula (1), wherein the molar amount of sulfonic acid groups derived from vinyl sulfonic acid monomers with respect to the molar amount of total monomer units is 50.0 to 98.0 mol %, and the polyvinyl sulfonic acid has an absorbance of 0.1 or greater (aqueous solution: 0.2 mass %, cell length: 10 mm) in a wavelength range of 255 to 800 nm.