An emerging mineral-based composite flame retardant coating: Preparation and enhanced fireproof performance

Abstract An emerging composite flame retardant has been prepared by sodium modification of natural mineral rectorite (REC), and waterborne intumescent fire retardant coating (IFR-Na-REC) containing sodium-modified rectorite (Na-REC) was successfully fabricated. The flame retardancy, morphology, structure, chemical composition and mechanical property of the intumescent coating were in detail investigated. The results showed that Na-REC could greatly promote the heat insulation effect of waterborne intumescent coatings. The temperature of the backside of steel plate for the IFR-Na-REC coating with 10% Na-REC was recorded to be 202 °C after 60 min of fire test, 24 °C lower than that of the control coating, and the flame retardant time reached up to 119 min. The enhanced fireproof performance could be attributed to the increased adhesion of the coating to the substrate and the formation of ceramic-like protective layer between rectorite and components in intumescent coating, which acted as a fire barrier to protect the internal matrix. Our work could offer a more benign approach to the general production of composite flame retardant coatings for fire protection.