Epoxy Intumescent Fire-Protective Materials: An Overview of Key Components and Their Effect on Coating Properties

Abstract Intumescent (thermally expanding) coatings are among the most effective, technologically advanced, and aesthetically viable solutions for fireproofing steel and wooden structures. When exposed to fire, these coatings undergo a series of complex chemical transformations, culminating in the formation of a low-thermal-conductivity charred foam layer. This process is driven by the thermo-oxidative degradation of a carefully engineered formulation. In addition to typical components—such as blowing agents and char-forming compounds—the polymeric binder is critical. It serves a dual role: first, as the medium facilitating the thermo-oxidative reactions, and second, as the structural matrix for the expanded char formed during initial intumescence. To regulate decomposition and supress active combustion, flame retardants are integrated into the formulation. This review examines the fundamental operating principles of fire-protective intumescent coatings and surveys the range of binders and flame retardants employed in their compositions.