Short duration hot seal for anodized metal surfaces

US5935656A · kind A · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Torsten Koerner · Goldkronach, DE
• Josef Kresse · Rommerskirchen, DE
• Wolf-Achim Roland · Solingen, DE
• Juergen Lindener · Goldkronach, DE

Key dates

• Filing date: Apr 20, 1998
• Grant date: Aug 10, 1999
• Expiry date: Apr 20, 2018

Classification

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

Abstract

A process for sealing anodized metal surfaces is characterized by bringing the anodized metal into contact with an aqueous solution at a temperature from 75.degree. C. to the boiling point of the solution for a time equal to from 0.5 to 2 minutes per micrometer of anodized layer thickness. The solution contains: a) from 0.0001 to 5 g/l of one or more alkali metal and/or alkaline earth metal ions and b) from 0.0005 to 0.5 g/l of one or more organic acids selected from: polycarboxylic acids with from 3 to 6 carboxyl groups; phosphonic acids; and/or polyphosphinocarboxylic acids, the solution containing a greater amount of metal ions of group a) than is needed to insure complete neutralization of the acids of group b).