Abstract: The performance of eggshell (CES) as an innovative environmentally friendly biofiller intumescent flame retardant coating was studied. Three flame retardant additives, namely ammonium polyphosphate II, pentaerythritol and melamine, were mixed with flame retardant filler and acrylic resin binder to make the intumescent flame retardant coating.The fire performance of the coating was tested by flame surface diffusion test, flame spread test, thermogravimetric analysis test and bond strength test. The test results showed that the test pieces of B, C, D and E did not show flame surface diffusion when exposed to flame. Eggshell biofillers with a mass fraction of 5.0% and 2.5% were added to coatings B and E, respectively, which improved fire resistance due to charring. The total flame propagation indices of the test pieces D and E were 4.5 and 5.0, respectively, showing excellent flame retardancy. The fire retardant coating has good water resistance, thermal stability and bond strength, and has good fireproof performance.

Key words: acrylic resin, chicken eggshell, bio-filler; intumescent coating