WATER-ABSORBING RESIN MANUFACTURING METHOD

摘要

The method for manufacturing a water-absorbing resin, by reversed phase suspension polymerization, includes the following: a step (1) in which, in a petroleum-derived hydrocarbon dispersion medium, in the presence of a dispersant, a slurry containing primary particles of a polymer is obtained by polymerization through dispersion of a first aqueous solution containing partially neutralized product A of a water-soluble unsaturated ethylene monomer having an acid radical in the molecule thereof; and a step (2) in which a slurry wherein the primary particles are agglomerated is obtained by polymerization through addition of a second aqueous solution, containing partially neutralized product B of a water-soluble unsaturated ethylene monomer having an acid radical in the molecule thereof, to the slurry obtained in step (1). The molar degree of neutralization X of partially neutralized product A is set higher than molar degree of neutralization Y of partially neutralized product B, and the difference between molar degree of neutralization X and molar degree of neutralization Y is set at 5% or greater. The dispersant used is at least one of a surfactant and a polymeric dispersant. The water-absorbing resin manufactured by the present method reduces odor originating in the dispersing medium and odor generated over time after absorption of liquid, etc.