Aluminum pigments for water-based paints


Dr. Andrea Fetz
Global Head Technical Marketing Automobile Coatings



It’s not only car bodies that need paint – there are also the rims and wheel caps, and even on the inside there are a large number of silver-coated parts such as door handles and decorative elements in the cockpit or on the dashboard. In view of the efforts made by the automotive industry to be more sustainable – think CO2 fleet consumption – there is an increasing demand for environmentally friendly water-based paints. Dr. Andrea Fetz, Global Head Technical Marketing Automobile Coatings, describes the aluminum pigment requirements for water-based paints.

"What are the requirements that have to be taken into account when developing aluminum pigments for water-based paints?"

Aluminum reacts with water, which can cause gas to form and have an extremely negative impact on the effect of the paint. But there are two ways to stop this reaction. Either you mix additives into the binding agent to prevent water from reaching the pigment surface. Or you can coat each individual pigment with silicate. Our HYDROMIC and HYDROXAL E aluminum pigments use the first option, whereas our HYDROLAN aluminum pigments use the second. The silicate layer makes for significantly more robust products. This means that coated aluminum pigments offer our customers more freedom when formulating their water-based paints and more variety in terms of applications. We specifically recommend our HYDROLANplus pigments for very demanding formulations. 

"A closer look at the markets shows that ECKART has already reached an extremely high level of innovation with its aluminum pigments for water-based paints. Where will your journey take you next?"

We have indeed made huge advancements in terms of our pigment systems for water-based paints. Nevertheless, our customers are always presenting us with new challenges. For example, we might have to further optimize the wetting of the aluminum pigments or adapt them precisely to the customer’s system. Customers often approach us with the wish to expand certain functionalities, such as the shelf life of refinish paints or gassing stability. And we are frequently faced with new regulatory requirements that change the requirements profile for water-based paints and the corresponding aluminum pigments. All these issues require even more innovative products, which we develop within the scope of “customizing.” This means that we test the pigments that we develop in our customers’ water-based paints to achieve the very best results.

"Autonomous driving is being hailed as the traffic concept of the future. Is this a promising market for ECKART’s aluminum pigments?"

Autonomous driving is a huge issue for everyone, and for silver metallic colors in particular, it is a real challenge. Experts were of the opinion that these color shades were not suitable for vehicle coatings because the metallic particles are not permeable to radar waves. However, the coating must be permeable to these waves to a certain extent so that the sensors that are mounted behind the bumpers can reliably detect the vehicle’s surroundings. Our research has shown that metallic coatings are in fact a viable option for autonomous vehicles. 

"So this is a breakthrough?"

You could call it that, yes! Ultimately, it all comes down to the formulation – and therefore also the particle size and pigment coating. We developed initial formulation concepts where the visual and aesthetic properties are not inferior to traditional silver metallic paints. Then we tested the radar permeability of these concepts and the results were positive. We reduced the proportion of aluminum pigments in these formulations and swapped them for our SYMIC Opaque and LUXAN pigments, which are based on synthetically produced fluorophlogopite or glass and are treated with our innovative coating process. This turns them into pearlescent pigments with unique lustrous effects. 

"How has the industry reacted to your concepts?"

The reactions have been very positive! We are also collaborating with paint, plastics, and automobile manufacturers on this very issue.



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