Technics and Properties of Plywood Manufacture with Modified Urea-Formaldehyde Resin

In this study, urea-formaldehyde resin was modified and used to bond three-ply plywood. The effect of hot press parameters on properties of plywood bonded by the modified urea-formaldehyde resin adhesive was investigated by an L(43) experimental design. The optimum technical parameters of hot press were obtained. Conclusions were as follows: (1) After modification, the free formaldehyde content of the urea-formaldehyde resin and the formaldehyde emission of resulting plywood were reduced by 74% and 70%, respectively; (2) The optimum technical parameters were 140°C of hot-pressing temperature, 80s/mm of hot-pressing time, 300g/m2 of glue content, and 0.8% of curing agent; (3) Under the optimum technical parameters, the bond strength and the formaldehyde emission of the plywood was 1.17MPa and 0.47mg/L, respectively.