Hydrophilic thickening agent and method of producing same

摘要

Provide is a cross-linked polymer which is a polymer of a water-soluble ethylenically unsaturated monomer, the cross-linked polymer being cross-linked by a water-soluble crosslinking agent. An aqueous liquid with a pH of 6.8 to 7.0 consisting of water and 1.0% by mass of the cross-linked polymer has an equilibrium compliance at 25° C. of 5.2×10−4 to 1.0×10−1 (1/Pa), while an aqueous liquid with a pH of 6.8 to 7.0 consisting of water and 0.2% by mass of a corresponding cross-linked polymer has a viscosity at 25° C. of 200 mPa·s or more.

主权项

1. A cross-linked polymer which is a polymer of a water-soluble ethylenically unsaturated monomer, the cross-linked polymer being cross-linked by a water-soluble crosslinking agent,
wherein an aqueous liquid with a pH of 6.8 to 7.0 consisting of water and 1.0% by mass of the cross-linked polymer has an equilibrium compliance at 25° C. of 5.2×10−4 to 1.0×10−1 (1/Pa), while an aqueous liquid with a pH of 6.8 to 7.0 consisting of water and 0.2% by mass of the cross-linked polymer has a viscosity at 25° C. of 200 mPa·s or more, wherein the water-soluble ethylenically unsaturated monomer consists of at least one compound selected from the group consisting of acrylic acid and a salt thereof, methacrylic acid and a salt thereof, 2-acrylamide-2-methylpropane sulfonic acid and a salt thereof, acrylamide, methacrylamide, and N,N-dimethylacrylamide, and wherein the water-soluble crosslinking agent comprises a water-soluble sucrose allyl ether, and wherein an amount of the water-soluble crosslinking agent is in a range of 0.1 to 2.0% by mass with respect to the water-soluble ethylenically unsaturated monomer.