Application of Modified UF Resin for Plywood Manufacturing

The authors made an experiment to bond plywood veneer using modified UF resin.They observed how the bonding performance of the resin could be influenced by the pH value,wheat flour addition and plywood assembly time.The authors found that following a decrease in pH,the bonding strength for the plywood,after both pre-pressing and hot-pressing,was improved,but the curing time and work life of the resin was reduced,and formaldehyde emission decreased.The quantity of flour greatly affected the viscosity of the UF resin,while increasing the flour was harmful for the bonding strength and formaldehyde emission,though it might improve the prepressing bonding strength.The most effective parameters were pH 4.5 and the addition of 20% flour.