| 摘要 |
PURPOSE:To perform polymerization under gentle conditions and to obtain safely a water-absorptive resin having a high water absorptivity, by polymerizing acrylic acid of a specified degree of neutralization with the aid of a sulfur- containing reducing agent and treating the product with an oxidizing agent. CONSTITUTION:Acrylic acid neutralized with a monovalent cation to a degree of neutralization of 30-100% is polymerized with the aid of a sulfur-containing reducing agent, and the product is treated with an oxidizing agent. Sodium hydroxide is desirable as a neutralizing agent used for neutralizing acrylic acid from the viewpoint of economy, safety and the water absorption performance of the obtained water-absorptive resin. Examples of said sulfur-containing reducing agents include sulfites, hydrogensulfites, thiosulfates and dithionites. Examples of said oxidizing agents include peroxodisulfates such as sodium peroxodisulfate and potassium peroxodisulfate.
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