Method of making an aqueous dispersion of fluoropolymers

US6794550B2 · kind B2 · utility

Assignee

• 3M INNOVATIVE PROPERTIES COMPANY · US

Inventors

• Klaus Hintzer · Woodbury, US
• Gernot Lohr · Altötting, DE
• Albert Killich · Altötting, DE
• Werner Schwertfeger · Altötting, DE

Key dates

• Filing date: Aug 28, 2001
• Grant date: Sep 21, 2004
• Expiry date: Oct 27, 2022

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S526/911
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The invention provides a process for removing steam-volatile fluorinated emulsifiers in their free acid form, from aqueous fluoropolymer dispersions. The process comprises adding a nonionic emulsifier, to the aqueous fluoropolymer dispersion and, at a pH-value of the aqueous fluoropolymer dispersion below 5, removing steam-volatile fluorinated emulsifier by distillation until the concentration of steam-volatile fluorinated emulsifier in the dispersion reaches the desired value.