The bark of indigenous coniferous wood, which in most cases is still considered a waste product in the wood industry, is often simply incinerated at sawmills or at best used as garden mulch. Frédéric Pichelin and his team at Bern University of Applied Sciences (BFH) in Biel/Bienne, however, deem the extraction of tannin from indigenous coniferous barks to offer tremendous potential. "We're working on an additional stage in the cascading use of wood products to utilize the abundance of bark material," explains Pichelin. "This opens up new sources of income for sawmills and downstream industries through renewable resources," he adds.
Although tannin extracts are already used to make wood adhesives, these mostly come from the barks of tropical timber species. The research team in Biel/Bienne has now succeeded in developing a two-stage aqueous extraction process to obtain impressively pure tannins from native spruce bark to which water can be added to produce adhesives that should be suitable for panel production.
The research team also sees great potential for the tannin extracts in developing composite materials for 3D printing. It is focusing above all on printable construction and design materials that are based entirely or predominantly on wood and bark. "The number of possible applications for bark extracts is huge," says Pichelin. "It remains to be seen where all this will actually lead, but Switzerland definitely mustn't miss the boat," he stresses. And who knows, perhaps the next LIGNA will be a major port of call.