This presentation will focus on various aspects of various aspects of urea-formaldehyde (UF) resin

​

adhesives to reduce formaldehyde emission, including hydrolysis of UF resin, lowering

​

formaldehyde/urea (F/U) mole ratio, modification of UF resins, or UF resin penetration into wood

​

cell wall. As well known, the formaldehyde is emitted from wood-based composite panels bonded

​

with UF resins by its hydrolysis, reversible reactions to the synthesis reactions of UF resin. I

​

n order to reduce the formaldehyde emission, one of the most promising ways is to reduce F/U

​

mole ratio for UF resin synthesis. However, lowering F/U mole ratio provide lower emission at the

​

expense of the loss of some mechanical properties. Thus, various ways of modifying UF resins

​

have been attempted such as addition of scavengers or isocyanate resin. In addition, the UF resin

​

penetration into wood cell wall is important to achieve a good adhesion in reconstituted wood

​

composites, which will be covered by this presentation.