Abstract: Effects of preparation technology of urea-formaldehyde resin modified with melamine(MUF)on property of plywood were studied.Results showed that formaldehyde emission of plywood conformed to E1 degree(≤1.5 mg/L) when formaldehyde/urea molar ratio was 1.1:1 and F/U molar ratio in weak acid stage was lower than 1.6:1.The bond strength of plywood using MUF resin in which content of melamine was beyond 3% did not satisfy to the requirement of type Ⅱ plywood (0.7 MPa).It was possible to decrease formaldehyde emission and improve bonding strength by adding 1% isocyanate curing agent in curing stage.Plywood,decorative plywood and blockboard manufactured with this MUF resin conformed to E1 degree required by standard.

Key words: urea-formaldehyde resin, melamine, formaldehyde emission, hardener, plywood