Urea-formaldehyde (UF) adhesive resins for wood

Urea-formaldehyde (UF) resins are the most important type of adhesive resins for the production of wood based panels. They convince by their high reactivity and good performance in the production and by their low price, however they lack in water resistance of the hardened resin owing to the reversibility of the aminomethylene link and hence the susceptibility to hydrolysis. This need can be overcome by introducing other components like melamine to the UF resin molecules. The former problem of subsequent formaldehyde emission can be considered as solved owing to the decrease of the content of formaldehyde in the resins during the last two decades. Modern laboratory test methods enable a deep insight into the chemical structure and the gelling and hardening behaviour of the resins. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.