Material-efficient production of lightweight three-layer particleboards from low-grade hardwood assortments with variable wood species content

In two sub-studies, lightweight, three-layer particleboards with a raw density of 650 kgm-3 were produced from defined particle mixtures of the wood species Betula pendula, Fagus sylvatica, Alnus glutinosa and Populus spp. Particleboards with densities of 600 kgm-3 and 550 kgm-3 were also produced for selected particleboard mixtures. In addition, three-layer particleboards were produced with surface layer particles from Picea abies and core layer particles from not debarked branch wood of Tilia cordata with a bulk density of 600 kgm-3 . Urea-formaldehyde resin was used as the binder in each case. The mechanicaltechnological properties of the particleboards were evaluated using standardized test methods. The moduli of elasticity, the internal bond strengths and the surface soundness of all the particleboards produced met the requirements of EN 312 for type P2 particleboards. Only the limit value for bending strength was slightly undercut by the particleboards with a bulk density of 550 kgm-3 . Overall, it was possible to produce standardcompliant, lightweight particleboards from wood species mixtures of low-grade hardwood assortments.