“Surface treatments are needed that do not alter the visual impression but enhance resistance“
We spoke to Dr Gerhard Grüll, head of department at Holzforschung Austria, about sustainability and other drivers of innovation in wood coatings. Interview by Bettina Hoffmann
What technologies do you see improving most in comparison? Where have you seen the biggest step up in performance in the last few years?
Dr Gerhard Grüll: I was very impressed by new wood products with UV curing coatings including excimer curing. Customers on wood products markets want to have surfaces that look and feel like uncoated wood. Gloss and wet look may be perceived as unnatural. At the same time, these products must fulfil very high requirements regarding resistance and durability. Surface treatments of wood are needed that do not alter the visual impression but enhance resistance significantly. This sounds like a miracle, but recent product developments delivered very matt surfaces and coatings without wet look. With polymer coating films, this can yield the required look and resistance and we have seen new products of high quality. I mentioned UV and excimer coatings in the beginning because the matting effects that can be achieved with excimer lamps in combination with UV curing coating systems are impressive and at the same time durable against chemicals and polishing.
Great emphasis is on products made from renewable raw materials and here, new binder technologies are emerging. Any pathway to achieve renewable raw materials sourcing must be acknowledged but at the same time they must have a sound and honest concept. In product development, never forget and start thinking of end of life scenarios and circular economy from cradle to cradle. We must start considering carbon footprint and sustainability as performance criteria.
Other than sustainability, what factors are driving your R&D activities?
Grüll: Sustainability is not an end in itself – this means that sustainability always forms the foundation of development for us, but is not the development goal in itself. This is always the customer’s requirement for the performance of the binders. In this context, we increasingly rely on renewable raw materials, which help us to achieve the primary performance goal. In the field of radical curing systems for UV and electron beam curing, systems with good cross-linking density are in demand. They offer good protection against aqueous and greasy media as well as mechanical resilience. We have made great progress here in recent years, with a bio-based content of up to 86%, and continue to work intensively on the topic.
Aqueous systems currently still often have the disadvantage of drying or hardening too slowly or are too soft for industrial applications. With the steadily growing market for these systems, one must also keep an eye on the needs of high-performance applications, which are often significantly higher than those in the DIY sector. We have recognised this requirement and developed a hybrid resin which develops the necessary hardness and scratch resistance without becoming brittle. And it also offers very fast drying for high throughput rates in production. Thanks to the targeted selection of raw materials, we are also able to offer a bio-based content of 90 % in this new development. The first generation of these binders is currently ready for the market, and further generations will certainly follow.
This interview is part of the Expert Voices section of the June issue of the European Coatings Journal.
