Usability of Particles Made from Lesser-Used European Wood Species Mixed with Spruce Particles in the Particleboard Core Layer.

The effects of produced wood particles from three wood species-alder, birch, and larch-added in various amounts in the particle mixture consisting of spruce particles and three tested wood species in a particleboard core layer on selected physical and mechanical properties of particleboard were studied. In a laboratory, 16 mm thick three-layer urea-formaldehyde (UF)-bonded particleboards were produced at 5.23 MPa, 240 °C, and with a 10 s/mm pressing factor. Two particleboard surface layers consisted of fine spruce particles. In the particleboard core layer, spruce particles were combined with particles from alder, birch, and larch. The tested particleboards containing alder, birch, and larch were characterized by approximately identical thickness swelling and they met the requirements of the conventional values stated by major particleboard manufacturers of 8-10%. The tested particleboard in all variations met the minimum strength value P2 particleboard in three-point bending, which is conventionally set at 11.0 MPa. The tested particleboard also exceeded the required values of modulus of elasticity in bending and internal bond strength. Analysis of the relationships demonstrated by the density profile confirmed that all three investigated wood species are usable in a mixture of core particles of high-quality particleboard in the recommended amounts (10, 15, 20%).