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The production of plywood from impregnated veneers allows a wood-based product protected in the entire cross-section to be obtained. The conducted research was focused on the properties of veneers impregnated with a mixture of potassium carbonate and urea, such as pH, wettability, colour change and surface roughness. In addition, the properties of plywood produced with melamineurea-formaldehyde resin, such as the shear strength and formaldehyde emission, were the subject of research as well. It was found that the impregnated veneers were characterized by an increased pH, increased wettability, a completely different colour and unchanged surface roughness. Moreover, the impregnation of the veneers caused a decrease in the bonding quality of the plywood and a reduction in formaldehyde emissions from the finished product. It can be concluded that the melamine-urea-formaldehyde adhesive is more suitable for the production of fire-resistant plywood than the urea-formaldehyde adhesive. [ABSTRACT FROM AUTHOR]

It was determined how the impregnation of birch veneers with a mixture of potassium carbonate and urea affected the fire protection properties, shear strength, modulus of elasticity and modulus of rigidity of plywood glued with PF and UF resin. Veneers were impregnated by soaking in aqueous fire retardant solutions with concentrations of 20% and 30%. Measurements of mass loss, burned area and time of ignition showed the fire protection provided to be very effective. Impregnation did not significantly affect the modulus of elasticity or modulus of rigidity of the plywood. Impregnation caused a decrease in bonding quality, especially in the case of plywood with UF resin soaked in water. For the samples with PF resin, both immersed and boiled in water, impregnation had less impact on the shear strength: its values exceeded 1 N/mm2, thus meeting the requirements of EN 314-2. [ABSTRACT FROM AUTHOR]

The study investigates the properties of lightweight (350-550 kg/m³) particleboardsmade using wood or rape particles and with veneers applied to their surfaces. Their suitability for the production of furniture and elements of interior design isdiscussed. Panels with veneer on their faces were made using a "one shot" pressing cycle. It was found that rape particles may be used for the production of lightweight particleboards, and that they are a good alternative to wood chips. Particleboards made of rape straw, covered with beech veneer during the pressing cycle in order to strengthen their subsurface layers, have better properties than the corresponding wood-chip-based particleboards. However, all the boards, throughout the whole density range, meet the requirements for P2 boards, i.e. boards intended for interior decoration and furniture production (MOR 11 N/mm², MOE 1600 N/mm²,IB 0.35 N/mm² according to EN 312). [ABSTRACT FROM AUTHOR]