Adhesives and insulating foams from softwood bark tannins
In collaboration with its European partners, VTT Technical Research Centre of Finland developed tannin extraction from softwood bark. This process creates at least 130kg of crude tannin powder from one tonne of dry wood bark, leaving 87% of the original bark mass available for incineration.
Tannin can be extracted from bark using hot water, after which the extract is dried into a powder. Drying the water extract into powder may not be necessary if the tannin is extracted near the site where glued wood products are manufactured.
In industrial use, tannin could be used to replace fossil chemicals in adhesives and insulating foams. Softwood bark tannins could be well suited for adhesive production for the manufacturing of wood products at sawmills. It could also enhance the fire resistance of insulating foams.
Click here for source (VTT Technical Research Centre of Finland)