Patent ID: 8741490

Claim:
A thickening agent for an alkaline battery, which comprises (A) a crosslinked polymer comprising, as essential constituent units, (a1) a water-soluble vinyl monomer and/or (a2) a vinyl monomer being converted into (a1) by hydrolysis, (b) a hydrolyzable crosslinking agent undergoing alkaline hydrolysis, and (c) a non-hydrolyzable crosslinking agent not undergoing alkaline hydrolysis, wherein (b) and (c) each has a content of 0.05% to 1% by weight based on the weight of (A), and which satisfies Requirements (1) to (3) described below: Requirement (1): the weight ratio (b)/(c) between (b) and (c) is from 1.0 to 5.0; Requirement (2): the solution (S1) described below has a viscosity of 25 to 100 Pa·s at 25° C.; Solution (S1): a solution obtained by mixing 98 parts by weight of an aqueous 40% by weight potassium hydroxide solution and 2 parts by weight of the thickening agent for an alkaline battery and stirring the mixture to form a uniform solution and allowing the solution to stand at 25° C. for 24 hours, Requirement (3): the solution (S2) described below shows a syneresis rate of 6.5% by weight or less; Solution (S2): a solution obtained by mixing 100 parts by weight of an aqueous 35% by weight potassium hydroxide solution, 2 parts by weight of the thickening agent for an alkaline battery, and 200 parts by weight of a zinc powder and stirring the mixture to form a uniform solution and allowing the solution to stand at 25° C. for 24 hours.