Increasing the durability, value and performance of European timbers by thermal treatment with reactive vegetable oils
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ECOTAN is a European funded project consisting of eight partners from the UK and The Netherlands (see partners). The principal objective of this project is to develop a commercial process for treating wood with a reactive vegetable oil.  The project started in April 2003 and will run for two years.

This project will generate the knowledge and innovative processing methods needed to optimise the treatment of wood with a novel reactive vegetable oil. Laboratory trials have demonstrated the potential of the treatment, with a major breakthrough being achieved through the use of elevated temperatures. This provides a combination of chemical and thermal wood modification processes.   

The process may be split into four key stages:

  • Wood is impregnated with the reactive vegetable oil using a vacuum pressure technique.
  • The impregnated wood is heated in this or another better-suited or cheaper vegetable oil at just above 100 °C until the major part of the water is “cooked” out of the wood.
  • Then the wood is heated in the oil to about 200 °C. At this temperature the reactive oil reacts with the wood and at the same time thermal modification of the wood takes place. This is also the start of the cross-linking process
  • Finally the remaining free oil needs to be removed from the wood and the surface needs to become clean. In this stage further oxidative cross-linking of the oil can take place.

The demand for dimensionally stable, durable timber is increasing across Europe. Traditionally, tropical timber species have been used to meet these needs. The use of modification processes, such as in this project, will allow European softwood species to be treated and used for higher end-value markets. The project partnership will look at various timber species, with treated material aimed at specific end-uses well known to the consortium. This will allow a thorough technical evaluation of the developing commercial process, with the potential of ultimately leading to commercially modified timber using reactive vegetable oils.