Application on Intrinsically Phosphorous Flame Retardant Waterborne Polyurethane and Intumescent Fire-Proofing Coatings

Five different components phosphorus-containing intrinsically flame retardant waterborne polyurethanes (FPU) were synthesized by combining FR-6 reacted with toluene diisocynate (TDI) and poly (propylene glycol) (PPG). Based on the FPU emulsion matrix, ammonium polyphosphate (APP), poly dipentaerythritol (DPER), melamine (MEL) as intumescent flame retardant system were added for preparing steel structure fire-proofing waterborne coatings. FT-IR, TGA, mechanical properties, cone calorimeter, back temperature, SEM, char strength and XPS, were used to characterize the properties of polyurethane film and coatings. The research show that the maximum thermal decomposition rate of the polyurethane film and coatings decreases with the increase of the FR-6 content. The residual char is improved at 800℃. The tensile strength increases, while the elongation at break has the opposite tendency. The heat release rate of the coating is lowest, and the char strength is the maximum, and the back stable temperature is 185.7 ℃ at 15% FR-6 combined. At the same time, the XPS comfirms that more N and P elements left can improve the fire resistance of fire-proofing coating.