LIGNIN AND LIGNINSULFONATE IN NONCONVENTIONAL BONDING - AN OVERVIEW

Recent developments in using lignin and ligninsulfonates as a binder in woodbased panels have been reviewed. Special consideration has been given to the Pedersen process, and to the use of ligninsulfonates as co-reactant in phenolic and aminoplastic adhesives. Stress has also been put on the use of ligninsulfonates in combination with tannin. Ligninsulfonates can be used up to about 15% without any significant deterioration of the mechanical properties or the swelling behavior for the production of particleboards of the type V100. Higher amounts of tannin can be substituted by ligninsulfonates for the production of particleboards of the type V20. The strength properties of particleboards bonded with lignin-tannin systems depend not only on the binder level but also on the pressing conditions and after treatments. Methods for activation of self-bonding properties of wood were discussed. Areas for further research work were highlighted.