Henkel Corporation

Michael Petschel

Mervet S Boulos

David C Montrose

Michael L Sienkowski

Robert W Miller

Equations have been developed to predict the amount of sludge formed during, and the values of several other characteristics of, zinc phosphating processes. Using these equations, novel compositions that achieve low sludge without sacrificing other characteristics of good zinc phosphate coatings have been discovered.

Sludge reducing zinc phosphating process and composition

An aqueous solution of manganese phosphate and phosphoric acid, preferably with little or no content of any material conventionally recognized as an accelerator or of any divalent metal ions other than manganese and iron, forms a good quality paint undercoating phosphate conversion coating on metal substrates, particularly on steel and galvanized steel substrates, when contacted by spraying or immersion with the substrates at a temperature of 54.degree.-65.degree. C. for a time of 0.5-5 minutes.

Moderate temperature manganese phosphate conversion coating composition

An aqueous solution of manganese phosphate and phosphoric acid, preferably with little or no content of any material conventionally recognized as an accelerator or of any divalent metal ions other than manganese and iron, forms a good quality paint undercoating phosphate conversion coating on metal substrates, particularly on steel and galvanized steel substrates, when contacted by spraying or immersion with the substrates at a temperature of 54.degree.-65.degree. C. for a time of 2-5 minutes.

The following water soluble materials are all satisfactory internal accelerators for otherwise conventional zinc phosphate conversion coating solutions: reducing sugars, starch, urea, and poly{acrylates and methacrylates}. Concentrates including these ingredients and otherwise conventional constituents of zinc phosphate conversion coating compositions, except for excluding conventional accelerators other than nitrate, are stable in composition during storage, unlike most conversion coating compositions containing conventional accelerators. Thus concentrates according to the invention are practical single-package concentrates that can be made into working phosphating compositions by dilution with water only.

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Rochester Hills, MI, United States of America

Michael Petschel