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ECJ spoke to Dr Markus Lettau, Head of R&D at Auro, about the performance of bio-based coatings. Interview by Bettina Hoffmann

For which type of application do you currently see the performance of bio-based coatings improving most?

Dr Markus Lettau: When I look at our own developments at Auro, we have made the greatest progress in the field of water-based paints and glazes. The increase in performance here is to be found in the availability of new bio-based binders that did not previously exist for use in bio-based paints. We are now in a position to develop products at the same technical level as in the conventional sector.

From our point of view, the weaker area is currently facade coatings, but this may also be due to the fact that we have only just begun to develop new products here and have not yet exhausted the full potential of available raw materials.

In the field of DIY products, which we serve at Auro, the raw materials portfolio has expanded considerably in recent years with regard to bio-based raw materials. It is conceivable, however, that the area of UV-curing systems or heavy corrosion protection still has some catching up to do in terms of bio-based raw materials, since no comprehensive solutions are available here yet or special solutions have to be replaced.

In the field of decorative coatings for wood and walls, however, a great deal has happened in the past, so that a large number of additives, from dispersants to defoamers, are now available as bio-based variants. In addition, it can be seen that the industry has clearly recognised the trend towards bio-based raw materials and is now in a state of upheaval.

What new sustainable components have you seen recently? What would be high on your wish list?

Lettau: The new sustainable components that could be seen at the European Coatings Show 2023 range from partially bio-based binders to one or the other sustainable additive. Often there are no 100 % bio-based products on the market yet, but one finds more and more bio-based additives for the formulation of paints and coatings. While products advertised as sustainable at the last ECS were often not really bio-based, but rather “only solvent-free”, they are now really bio-based where they say bio-based. The industry has clearly recognised the trend! We see that the pool of available raw materials is constantly growing.

We ourselves would like to see more bio­based additives from all areas, from dispersants to defoamers, in or-der to achieve more freedom in formulation development. Often, the one available bio-based product is not compatible with the rest of the system and thus cannot always be replaced one to one by a second one. Thus, unavailability can also be decisive for us as a natural paint manufacturer for the overall development of a new product.