The hydro thermo mechanical densification process depends considerably from the parameters temperature, conditioning time and pressing time. A Master thesis examines their impact to mechanical properties. Due to resource issues, the economic utilization of fast grown and low value wood has currently received a lot of attention. Viscoelastic thermal compression (VTC) is a densification process for veneers that takes advantage of lignin glass transition at elevated temperatures. This patented process takes place in a specially equipped hot press with heating,
cooling and steam boiler components. The process consists of a conditioning phase by steaming the hybrid poplar veneers, the compression phase and a cooling phase in order to solidify the lignin. The experimental design of the current study comprised different treatment combinations of conditioning time, compression rate and compression time, and evaluation of the modulus of elasticity in bending (MOE), modulus of rupture (MOR), shear strength parallel to the grain and glueability with different loading rates. The results show that increasing conditioning time elevates MOE, MOR and shear strength. The rate of compression did not show a significant trend and compression time improves MOR and MOE. Shear strength was not
influenced in any systematic trend. An optimal phenol formaldehyde solid resin loading rate in the range of 50 g/m2 and 70 g/m2 could be identified.