| Résumé : |
Corrosion is a process where a refined metal, such as aluminum or iron or alloys such as steel, undergoes degradation. In scientific terms, corrosion is an electrochemical process leading to oxidation of the metal and returning it to its natural state, such as iron being converted to iron oxides.
Electrochemical reactions eat away at the underlying metal substrate, sometimes degrading it to such an extent that it creates aesthetic, mechanical, or structural failures. The economic impact of corrosion is enormous. In a recent report, corrosion was estimated to cost the global economy more than $2.5 trillion annually, or approximately 3.4% of global gross domestic product (GDP).1 Preventing corrosion is clearly an important goal, and paints and coatings play an important role in this never-ending battle. Coatings applied to metal substrates can have a variety of purposes, including the enhancement of aesthetics such as gloss and color, or various functional purposes such as thermal insulation, sound dampening, or antimicrobial properties.
However, in many cases the most important role of a coating on a metal substrate is protection of the metal surface from the environmental effects that lead to corrosion. Waterborne direct-to-metal (DTM) coatings are just one category of coatings designed to protect metal substrates.
We begin by considering the science behind the corrosion process and the methods by which a coating can prevent corrosion. Then we will examine what is meant by direct-to-metal and how the term “DTM coating” is typically discussed in the industry, followed by a description of one-component (1K) DTM coatings based on acrylic latex polymers, which are the most common type of waterborne DTM coatings. We will also discuss principles of formulating waterborne acrylic DTMs for maximum performance over metal substrates.
Finally, we will present a twopart, roundtable Q&A, where industry experts discuss the current trends and technology advances. |
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Waterborne direct-to-metal coatings in COATINGS TECH, Vol. 19, N° 6 (07/2022)
