Study on preparation and fire-retardant mechanism analysis of intumescent flame-retardant coatings

An intumescent flame-retardant coating was prepared by unsaturated polyester resin and epoxy resin as two-component matrix resins, ammonium polyphosphate (APP) as acid source, melamine (Mel) as the blowing agent and pentaerythritol (PER) as carbon agent, expandable graphite as synergistic agent, adding titanium dioxide (TiO₂), solvent and other assistants. Results showed that such a coating had excellent physical-chemical properties. When the thickness of the coating on the wood matrix reached 2.0 mm, the limit of fire-endurance could get to 210 min. And the various component thermal characteristics, decompose processes and interactions of the flame-retardant coating system were investigated by DSC and TGA. The contribution of phosphorus to the formation of the final charring layer and their morphological structures was studied by SEM, XRD and FTIR. On the basis, the flame-retardant mechanism of the intumescent flame-retardant coating was systematically investigated.