Silica based ion-exchanged pigments: fulfilling the demand for non-toxic environment friendly anti-corrosion pigment products

David J.Kent; Timothy E.Fletcher, Grace GmbH & Co.KG, UK

In the mid 1980’s pigments based on ion-exchanged silica products became available as a novel approach to the challenge of finding non-toxic, environment friendly alternatives to the established anti-corrosive pigment technologies. In the beginning the main target was the replacement of toxic materials such as Red Lead and Chromate VI based products. Now more than 20 years on these products have become established as the most promising replacements to chromates, enabling the coil-coatings industry for example to produce primers compliant with forthcoming European regulations.

More recently environmental concerns have led to heavy metal based materials including Zinc compounds becoming key targets for replacement. Ion-exchanged silica based pigments used alone or in combination with other inhibitor materials have become increasingly established in alternative formulations for a wide variety of protective, industrial and maintenance applications.This paper examines the success of these products based on proven performance and driven also by legislation regulating the use of the more traditional toxic and/or environmentally damaging materials.

The latest developments with respect to products and formulations are also discussed. Alongside improved cost-efficiency, the key focus of these developments has been on improved performance in higher solids and water-borne formulations, as well as reduced dependency on specific formulation components to provide a greater degree of freedom to the formulator.