A molar ratio of formaldehyde to urea in UF resins was selected within a range of 1:1.17. The properties of the UF resin are given Table 1. The amount of UF resin (oven-dry, solid wood basis) is presented in Table 2. Ammonium chloride 2% (dry resin basis) as a resin hardener, and wax solution 2% (dry solid wood basis) to improve the water resistance of all MDF panels were used.