Short-term heat-sealing of anodized metal surfaces with surfactant-containing solutions

US6059897A · kind A · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Torsten Koerner · Goldkronach, DE
• Josef Kresse · Rommerskirchen, DE

Key dates

• Filing date: Nov 30, 1998
• Grant date: May 9, 2000
• Expiry date: Nov 30, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25D11/246
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Process for post-sealing anodized metal surfaces, characterized in that the anodized metal is contacted with an aqueous solution for a period of between 0.5 and 2 minutes per micrometer of anodized coating thickness, which solution is at a temperature of between 75.degree. C. and its boiling point and has a pH of from 5.5 to 8.5 and which contains: PA1 (a) a total of 0.0004 to 0.05 g/l of one or more cationic, anionic or non-ionic surfactants; and PA1 (b) a total of 0.0005 to 0.5 g/l of one or more organic acids selected from cyclic polycarboxylic acids having 3 to 6 carboxyl groups and/or phosphonic acids. Non-ionic surfactants are preferred as the surfactants while polyphosphinocarboxylic acids are preferred as the acids. Alkali and/or alkaline earth metal cations, preferably Li and/or Mg ions, are optionally present in quantities of 0.0001 to 5 g/l.