Process for the production of a superabsorbent polymer

US8198385B2 · kind B2 · utility

Assignee

• Evonik Stockhausen GmbH · US

Inventors

• Herbert Gartner · Baden-Baden, DE
• Jorg Harren · Baesweiler, DE
• Marc Hager · Bischwiller, FR
• Harald Plochinger · Bühl, DE
• Daniel Fricker · Rœschwoog, FR
• Hans-Peter Kohler · Bühlertal, DE
• Sabine Auernig · Achern, DE

Key dates

• Filing date: Nov 9, 2010
• Grant date: Jun 12, 2012
• Expiry date: Feb 3, 2031

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08K5/175
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to process for the preparation of a superabsorbent polymer comprising the steps of a) subjecting an aqueous monomer mixture containing at least one α,β-ethylenically unsaturated monomer; at least one monomer bearing at least two α,β-ethylenically unsaturated groups; iron ions in an amount of 0.1 to 3 wppm based on the total weight of the aqueous monomer mixture; and at least one chelating agent in an amount to provide a mol ratio of chelating agent to iron ion of 0.8 to 4.0 to free radical polymerization in an reactor to obtain a super-absorbent polymer; and b) recovering the superabsorbent polymer, whereby if the process is continuous and is run in an agitated reactor the upper limit of the mol ratio of chelating agent to iron ion is 4.0 for a throughput of total reaction mixture through the reactor of at most 1.3 kg/h per liter reactor volume.