The Effect of Treatment with Fire Retardant on Properties of Birch Veneer and Manufactured Fire-Resistant Plywood

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.