Sulfonic group-containing, maleic acid-based, water-soluble copolymer aqueous solution and powder obtained by drying the aqueous solution

Abstract

Provided is a copolymer aqueous solution which exerts a high calcium carbonate-deposition suppressing ability even under high hardness condition, has excellent storage stability, and suppresses coloring of a detergent to yellow even when used as a detergent raw material. The water-soluble copolymer aqueous solution includes a water-soluble copolymer and hydrogen peroxide as essential components, in which: the water-soluble copolymer at least includes, as its structure, a structural unit originating from a monoethylenic unsaturated dicarboxylic acid (or dicarboxylate) monomer having 4 to 6 carbon atoms or its anhydride (a) at 30 to 60 mol %, a structural unit originating from a monoethylenic unsaturated monocarboxylic acid (or monocarboxylate) monomer having 3 to 8 carbon atoms (b), and a structural unit originating from a monoethylenic unsaturated monomer having a sulfonic (or sulfonate) group (c); the water-soluble copolymer has a weight average molecular weight of 1,000 or more and 50,000 or less; the water-soluble copolymer aqueous solution has a weight ratio of the hydrogen peroxide of 10 ppm to 50,000 ppm with respect to a solid content of the water-soluble copolymer aqueous solution; and the water-soluble copolymer aqueous solution has a weight ratio of water of 33% to 99%.