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US 12,491,495 B2Granted
Method for preparing super absorbent polymer
AssigneeLG Chem, Ltd.
InventorsHyungki Yoon, Young Jae Hur, Jin Hyuck Ju, Taebin Ahn, Dong Hoon Park, Kwangin Shin, Jae Soon Kim
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Abstract
The present disclosure relates to a method for preparing a super absorbent polymer. More specifically, it relates to a method for preparing a super absorbent polymer capable of preparing a super absorbent polymer in which the residual monomer content and the extractable content are simultaneously reduced by adding a reducing agent capable of a redox reaction with a thermal polymerization initiator before drying the hydrogel polymer.
Claims10
A method for preparing a super absorbent polymer, comprising:
- preparing a monomer composition containing an acrylic acid-based monomer having acidic groups in which at least one of the acidic groups is neutralized, an internal cross-linking agent, and a thermal polymerization initiator;
- preparing a hydrogel polymer by cross-linking polymerization of the monomer composition;
- mixing the hydrogel polymer with a reducing agent in an amount of 10 parts by weight to 100 parts by weight based on 100 parts by weight of the thermal polymerization initiator;
- chopping the hydrogel polymer;
- forming a base resin by drying and pulverizing the hydrogel polymer after the chopping;
- and
- forming a surface cross-linked layer on at least a part of a surface of the base resin by further cross-linking the surface of the base resin in the presence of a surface cross-linking agent,
- wherein the reducing agent comprises at least one selected from the group consisting of sulfoxylates and metabisulfites.
5 more elements
Dependencies are inferred from the claim text.