Method for producing powdered cationic water-soluble polymer compound, sludge dewatering agent, and sludge dewatering method

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a powdery cationic water-soluble polymer compound with a high molecular weight from a monomer mixture containing 97 mol% of a quaternary ammonium group-containing cationic acrylate monomer and a quaternary ammonium group-containing cationic methacrylate monomer in a predetermined ratio, a sludge dehydrating agent comprising the polymer compound, and a method for dehydrating sludge.SOLUTION: The method for producing a powdery cationic water-soluble polymer compound having a theoretical cation equivalent value of 5.0 meq./g and a 0.5% salt viscosity of 10-30 mPa s (25°C) comprises: subjecting a monomer mixture containing a quaternary ammonium group-containing cationic acrylate monomer (A), a quaternary ammonium group-containing cationic methacrylate monomer (B), and another monomer (C) to aqueous solution polymerization; cutting the resulting copolymer to 10 mm; and drying, wherein the monomer mixture is prepared so as to satisfy a total monomer [monomer (A)+(B)+(C)] concentration of 70 mass%, a monomer (A)/(B) ratio of 7-9 (molar ratio), and a [monomer (A)+(B)]/(total monomer) ratio of 97-100 (mol%).