Independence from fossil resources is not a matter of one big discovery but of many small steps. Researchers at the Fraunhofer Institute have succeeded in taking such a step. They can now produce a paint primer based on lignin, a by-product of paper production and the production of bioethanol. Compared with petrochemical raw materials the primer has a significantly improved CO2 balance.
Bio-binder for primer formulation
In the development of alternatives to petrochemicals, lignin has often attracted the attention of scientists. Due to its challenging properties though, such efforts have had limited success. For example, the chemical composition of lignin depends on its source (soft wood, hard wood, straw) whether it comes from paper production and is mixed with other substances or is a by-product of biofuel. Accordingly, the production of a substance with consistent properties is highly complex. "Most previous approaches were based on producing lignin monomeric starting materials, which always have the same properties. Due to the different composition of the starting material, this is quite complex," explains Yvonne Wilke from Fraunhofer IFAM. "We took a different approach by standardizing and modifying the whole substance. This gives us a raw material that we can say is always the same within certain limits." The experts at Fraunhofer IFAM then used the standardized mixture as raw material for binders for primer formulations. The result is a primer with properties such as corrosion protection, adhesion or applicability comparable to primers based on petrochemicals.
Primers made of plant residues
Especially when both manufacturers and end users call for sustainable products such bio-based solutions are particularly interesting. In the automotive industry, for example, the carbon footprint is an important selling point. Using bio-based primers and paints, this can be significantly improved. And since the lignin-based primer of the Fraunhofer IFAM has comparable properties to those of conventional primers, no compromise would have to be made in terms of quality.
"Independence from fossil fuels is a tremendous goal. Especially considering the number of products that are still based on fossil fuels," says Wilke. "With our project, we've been able to take a step in the right direction and to show that lignin is a real alternative in the manufacture of primers and adhesives. That it brings us a bit closer to independence from petrochemicals as well."