Henkel Kommanditgesellschaft Auf Aktien

Dieter Brodalla

Willi Wuest

Willi Buchmeier

Juergen Lindener

Loert De Riese-Meyer

Winfried Kirchhoff

Werner Huppertz

Georg Wagner

James W Costello

Karl-Heinz Munk

Helmut Blum

Rainer Osberghaus

Juergen Foell

Christine Schroeder

Frantisek Jost

Harald Bossek

Harald Wennemann

Wolfgang Riedel

Herbert Leiter

Hans J Goehausen

Roland Geissler

Andreas Buhl

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

A process and circuitry for the electrolytic coloring of an anodized article of aluminum or aluminum alloy in a coloring bath containing at least one metal salt for coloring the article. The process comprises applying to the coloring bath a controllable, asymmetrical and substantially sinusoidal a.c. voltage of substantially constant frequency. The sinusoidal a.c. voltage is obtained from a voltage source supplying a symmetrical sinusoidal a.c. voltage and at least one of the two current paths is divided into two parallel main lines and fed to electrical components whereby the amplitude level of the positive half wave and the amplitude level of the negative half wave and the ratio of the amplitude level of the positive half wave to the amplitude level of the negative half wave of the a.c. voltage applied to the coloring bath are made variable and adjustable independently of one another, adjusting the positive half wave and the negative half wave to the desired values, and recombining the main lines to form the a.c. voltage applied to the coloring bath.

Circuitry for the electrolytic coloring of anodized aluminum surfaces

In the process of sealing decorative anodized aluminum oxide coatings in hot aqueous solutions, superior results are obtained when the sealing solutions contain 1-phosphonopropane-1,2,3-tricarboxylic acid, 1,1-diphosphonopropane-2,3-dicarboxylic acid, and/or alkali metal and/or alkanolamine salts of these acids. The presence of these acids or their salts prevents the formation of bloom and allows shorter sealing times with equivalent quality, and the addition of as little as 1 ppm of aluminum ions to such solutions also prevents iridescence.

Process for sealing 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

Process for the electrolytic coloring of anodized aluminum surfaces

A process for the electrolytic coloring of anodized surfaces of aluminum or aluminum alloys using alternating current or direct current superimposed on alternating current, the electrolytic coloring being carried out with an electrolyte which contains cationic organic dyes and, optionally, conducting salts.

Electrolytic coloring of anodized aluminum

Liquid phosphate-free single phase degreasing compositions for aluminum surfaces containing one or more builders, sequestrants and surfactants in aqueous alkaline solution, particularly containing alkali metal and/or ammonium carbonate, alkali metal and/or ammonium hydrogen carbonate, one or more acrylic polymers, optionally one or more other complexing agents which complement or partly replace the acrylic polymers, one or more anionic or nonionic surfactants, optionally other active substances and/or auxiliaries of the type normally used in degreasing compositions and water.

Liquid, phosphate-free single phase degreasing compositions

A process and composition for producing colorless, cold-sealed, anodized aluminum or aluminum alloy surfaces. The composition comprises an aqueous solution containing nickel ions and a solution of at least one azo or azo metal dye, the colors imparted by the nickel ions and dye offsetting each other.

Colorless sealing layers for anodized aluminum surfaces

Preservatives for aluminum surfaces in the form of a polymer dispersion based on an acid-group-containing acrylate copolymer which is cross-linked with divalent metal salts, which contains plasticizers and surfactants, and which, optionally, contains oxidized polyethylene and/or a copolymer of styrene and maleic acid anhydride. The preservatives are suitable for the preserving aftertreatment of aluminum, particularly electrolytically oxidized aluminum.

Method and composition for preserving aluminum surfaces

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Duesseldorf, Germany

Dieter Brodalla