Bitumen is widely used as a basis for roofing products. It has excellent functional properties for this application, but it is made from petroleum, just like the widely used polymers APP and SBS. In addition, the quality of the bitumen supply varies greatly, partly because a number of European bitumen factories (including those in Rotterdam and Antwerp) have closed down.
Lignin as the basis
In DISCOVER 2, researchers from Wageningen Food & Biobased Research looked for environmentally friendly alternatives for existing bitumen-based roofing materials. Side streams from the pulp and paper industry and the agro-food industry were examined in particular. One of the usable alternative raw materials turned out to be lignin. This natural glue has already proven to be a suitable renewable alternative to bitumen for use in asphalt.
The key bottleneck was mixing the lignin and the other necessary biobased components into a homogeneous mass. By using physical and chemical modification technology, this was successfully achieved. “A crucial step,” says Richard Gosselink, expert leader of Wageningen Food & Biobased Research. “Thanks to this project, we have gained a good understanding of the mixing process.” This technological knowledge is also being used in another ongoing project entitled 100% biobased bitumen for asphalt. Gosselink: “Asphalt needs a different hardness than roofing, so a different composition of biobased components is needed.”
Wageningen Food & Biobased Research is now orienting itself on possible partners for the next step on the road to 100% bio-based roofing products: the making of a prototype. According to researcher Ted Slaghek, the prototype should be ready within three years. He expects that it should be possible to scale up the technology so that a fully-fledged bio-based alternative can come onto the market within six to seven years. “The market is showing great interest. Roofing manufacturers are looking for environmentally friendly alternatives for their existing products.”
The DISCOVER 2 project is a follow-up to an earlier project within the Circular and Biobased Performance Materials (CBPM) programme. It is co-funded by the Top Sector Chemicals (ChemistryNL).
For more information, please visit the website of Wageningen University & Research (WUR).