Abstract: A flame-retardant coating was prepared by using of urea-formaldehyde resin (UF) or pure acrylic emulsion resin (PEA), melamine polyphosphate (MPOP), melamine (MEL), and pentaerythritol (PER). The thermal stability and flame-retardant mechanism of the flame retardant coating were investigated by thermogravimetric analysis. The flame-retardant properties of the wood coated with this flame retardant coating were evaluated by cone calorimetry and limited oxygen index. Compared with UF/MPOP system, PEA/MPOP exhibited better flame-retardant properties, higher thermal stabilities, and stronger smoke suppression, and its limited oxygen index value was increased by 9.4 %. Moreover, its heat release rate, total heat release rate and rate of flue gas were reduced due to the integrated carbon layer formed on the surface of the wood.

Key words: urea-formaldehyde resin, pure acrylic emulsion, instumescent flame-retardant coating, flame retardant mechanism