The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2012
Filed:
Nov. 09, 2010
Herbert Gartner, Baden-Baden, DE;
Jorg Harren, Baesweiler, DE;
Marc Hager, Haguenau, FR;
Harald Plochinger, Buhl, DE;
Daniel Fricker, Roeschwoog, FR;
Hans-peter Kohler, Buhlertal, DE;
Sabine Auernig, Lauf, DE;
Herbert Gartner, Baden-Baden, DE;
Jorg Harren, Baesweiler, DE;
Marc Hager, Haguenau, FR;
Harald Plochinger, Buhl, DE;
Daniel Fricker, Roeschwoog, FR;
Hans-Peter Kohler, Buhlertal, DE;
Sabine Auernig, Lauf, DE;
Evonik Stockhausen GmbH, Krefeld, DE;
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.