Rehap recently published results on the development of extracting tannin from softwood bark and the upscaling at Bio Base Europe Pilot Plant (BBEPP). Continued studies reveal further innovations.

The project, working closely with the team at BBEPP, have recently performed and evaluated tests on the hot water extraction of tannin from softwood bark and found that the best technique for doing so was using decantation (separating mixtures by removing a liquid layer free from precipitate) combined with centrifugation (separating the mixture through spinning).
This technique was successfully scaled-up at BBEPP to make 150Kg of tannin solution which was sent to partners Foresa for further modification.

Foresa, a producer of formaldehyde and resins, is currently carrying out laboratory tests with tannin samples sent by VTT, Technical Research Centre of Finland Ltd, in order to eventually develop, validate and up-scale products suitable for application in the targeted final bioproducts.

Foresa have been creating boards, also known as wooden panels for later use in the green construction industry, from the resin (a substance of plant origin) from tannin. These wooden panels are manufactured to be free of phenol, a very toxic adhesive in binding wood, and replaced with tannin resins. All resins need additives or catalysts to start the reaction, however these products are quality controlled to ensure their concentration in the wood is very low.

Once the resin has been tested to ensure it has no bad properties in it, Foresa will clarify the process, for example, the amount of glue, catalyst and additives as well as the time and temperature of press.

Once all the processes have been defined, Foresa will manufacture thousands of wooden panels before they are validated to be applied for construction of industrialised composite for green buildings.