Intumescent Flame Retardant Coating

Intumescent FR coatings contain a three-component system: acid source (ammonium polyphosphate, APP at 20–40%), carbon source (pentaerythritol or starch at 10–20%), and blowing agent (melamine at 10–20%) in acrylic or PU binder at total add-on of 100–200 g/m². Upon exposure to flame at 250–300°C, the system undergoes endothermic decomposition, releasing water and NH₃ while forming a multi-cellular carbonaceous char 10–50× original thickness. Char insulates substrate and reduces heat release rate by 60–80% (cone calorimeter, ISO 5660). FR performance meets EN 13501 Class B and NFPA 701 after 20 home laundering cycles at 40°C.