Henkel Kommanditgesellschaft Auf Aktien

Juergen Lindener

Loert De Riese-Meyer

Wolf-Achim Roland

Dieter Brodalla

Christine Schroeder

Torsten Koerner

Volker Sander

Josef Kresse

Willi Wuest

Peter Kuhm

Willi Buchmeier

Juergen Foell

Loert D Meyer

Short duration hot seal for anodized metal surfaces

Method of compacting anodized metals with lithium and

Method for electrolytic coloring of aluminum surfaces using alternating

Electrolyte additive for a colorant bath for coloring aluminum and

Substituted diphenols, phenyl ethers containing two oxygen atoms attached to a benzene nucleus, and naphthols are more practically effective than previously known additives in stabilizing tin (II) salts, in electrolyte solutions useful for coloring anodized aluminum by electrolysis therein, against oxidation to tin(IV) by reaction with ambient oxygen. Preferred additives include 2-tert-butyl-1,4-dihydroxybenzene, methylhydroquinone, trimethylhydroquinone, 4-hydroxynaphthalene-2,7-disulfonic acid, and p-hydroxyanisole. If p-toluenesulfonic acid or napthalene sulfonic acid are also used in the electrolyte, the throwing power can be greatly improved.

Process for dyeing anodized aluminum

Undesirable greenish tinges that normally result when coloring anodized aluminum by AC electrolysis in solutions of silver salts can be avoided by adding to the electrolytes an appropriate amount of p-toluenesulfonic acid and/or its salts. The coloring solution may also contain (i) sulfuric acid, (ii) alkali metal, ammonium and/or alkaline earth metal salts of sulfuric acid and/or (iii) alkali metal, ammonium and/or alkaline earth metal acetates.

Process for coloring anodized aluminum by AC electrolysis

Growing community of inventors

Duesseldorf, Germany

Juergen Lindener