Method for producing expandable graphite intercalation compounds using phosphoric acids, and graphite foil

US6645456B2 · kind B2 · utility

Assignee

• SGL Technik GmbH · DE

Inventors

• Oswin Öttinger · Meitingen, DE
• Hubert Malik · Meitingen, DE

Key dates

• Filing date: Jan 25, 2001
• Grant date: Nov 11, 2003
• Expiry date: May 6, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B32/225
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method for producing expandable graphite intercalation compounds uses a thermal polyphosphoric acid which is added to an intercalation agent or to graphite. Preferably, the thermal polyphosphoric acid is used in a mixture with red, fuming nitric acid. Products produced from the graphite intercalation compounds through the expanded graphite stage, such as graphite foils, graphite laminates or graphite seals, have a comparatively high fluid tightness, are relatively resistant to oxidative attack, and can have comparatively high strengths. A further advantage is a good handling ability of the thermal polyphosphoric acids. A graphite foil is also provided.