Anti-stick processing aids and use thereof in the production of water-absorbing particles

US11680184B2 · kind B2 · utility

Assignee

• Evonik Superabsorber LLC · US

Inventors

• Christoph Loick · Duisburg, DE
• Scott J. Smith · Greensboro, US
• Anne Ix-Mund · Kerken, DE
• Nicolaas De Bruin · Krefeld, DE
• Laurent Wattebled · Düsseldorf, DE
• Michael M. Azad · Reidsville, US
• Frank Loeker · Krefeld, DE

Key dates

• Filing date: Jul 24, 2015
• Grant date: Jun 20, 2023
• Expiry date: Oct 16, 2035

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J2220/68
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention relates to an anti-stick processing aid for use in a process for producing water-absorbing polymers, comprising the steps of:i) mixing (α1) 0.1 to 99.999% by weight of polymerizable, ethylenically unsaturated monomers containing acid groups, or salts thereof, (α2) 0 to 70% by weight of monomers copolymerizable with (α1), (α3) 0.001 to 10% by weight of crosslinkers, (α4) 0 to 30% by weight of polymers, (α5) 0 to 80% by weight of water, and (α6) 0 to 20% by weight of assistants, (ii) free-radical polymerization with crosslinking to form a hydrogel polymer, (iii) drying the hydrogel polymer, (iv) grinding and sieving the hydrogel polymer, (v) surface postcrosslinking the hydrogel polymer and (vi) drying and finishing the water-absorbing polymer, wherein the anti-stick processing aid is used before and/or in steps (iii).