Abstract: The theoretical researches on urea-formaldehyde resin and its practice in wood industry were reviewed in detail. With application of nuclear magnetic resonance in structure researching of urea-formaldehyde resin, minor structural differences can be clearly distinguished. Effects of reaction condition in urea-formaldehyde resin production, especially during the acid stage, on the formaldehyde emission were discussed. Modes of modification of urea-formaldehyde resin were listed. Their properties after modification were also studied.

Key words: urea-formaldehyde resin, low formaldehyde emission