Process for producing stable emulsion of polymer

摘要

There is provided a process for preparing a stable polymer emulsion characterized by polymerizing a radical-polymerizable monomer having unsaturated bond by using a water-soluble catalyst in an aqueous medium and in the presence of a water-soluble polymer containing chemically bonded monomeric units of methacrylic acid or its salt and monomeric units of ethylenically unsaturated sulfonic acid or its salt, said polymerization being conducted at a pH of 4 or lower.