Process for reducing the amount of fluorinated surfactant in aqueous fluoropolymer dispersions

US6825250B2 · kind B2 · utility

Assignee

• 3M INNOVATIVE PROPERTIES COMPANY · US

Inventors

• Rebekka Epsch · Berlin, DE
• Klaus Hintzer · Woodbury, US
• Gernot Lohr · Altötting, DE
• Werner Schwertfeger · Altötting, DE

Key dates

• Filing date: May 5, 2003
• Grant date: Nov 30, 2004
• Expiry date: May 5, 2023

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L27/12
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The present invention provides a process of reducing the amount of fluorinated emulsifier in an aqueous fluoropolymer dispersion by contacting the aqueous fluoropolymer dispersion with an anion exchange resin in a non-fixed resin bed, the process comprising:(a) mixing the aqueous fluoropolymer dispersion with an effective amount of a surfactant so as to stabilize the fluoropolymer dispersion while being contacted with the anion exchange resin;(b) contacting the aqueous fluoropolyrner dispersion with an anion exchange resin by agitating the aqueous fluoropolymer dispersion with an effective amount of anion exchange resin for a time of less than 4 hours to reduce the amount of fluorinated emulsifier in the aqueous fluoropolymer dispersion to a desired level; and(c) separating the anion exchange resin from the aqueous fluoropolymer dispersion.