Influence of the formaldehyde content of waterbased melamine formaldehyde resins on physical properties of Scots pine impregnated therewith

This paper presents a systematical approach to the properties of wood impregnated with different waterbased melamine resins, to provide a basis for further research. Therefore, ten commercially available methylated melamine formaldehyde resins with increasing ratios of melamine to formaldehyde have been compared in respect of their influence in dimension stabilisation, sorption behaviour, formaldehyde emissions, and water repellency of the treated wood. The dimension stabilisation caused by resin molecules that penetrated the wooden cell wall correlated with the molar mass of the resins used for impregnation. The changes in the sorption isotherms were attributed to a bulking effect. Formaldehyde emissions during and after curing increased with an increasing ratio of formaldehyde to melamine in the resins.