Method for recovering fluorinated emulsifiers

US6642415B1 · kind B1 · utility

Assignee

• 3M INNOVATIVE PROPERTIES COMPANY · US

Inventors

• Stephan Führer · Burgkirchen an der Alz, DE
• Klaus Hintzer · Woodbury, US
• Gernot Lohr · Altötting, DE
• Werner Schwertfeger · Altötting, DE

Key dates

• Filing date: Apr 12, 2002
• Grant date: Nov 4, 2003
• Expiry date: Apr 12, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C02F2103/38
• WIPO field: Environmental technology
• WIPO sector: Chemistry

Abstract

Fluorinated emulsifiers, in particular, perfluorooctanoic acid are bound to anionic exchange resins for the purification of aqueous effluent from the production of fluoropolymers. Said emulsifiers may be quantitatively eluted from the exchanger with a water-miscible organic solvent, containing a small amount of ammonia. It is of advantage to distil off the ammonia containing solvent, recycle the emulsifier to a further polymerization and recycle the ammoniacal solvent for elution. Addition of alkalis improves the elution efficiency.