Expandable Graphite in Fire-Resistant Coatings: Formulation and Key Performance Factors

Expandable graphite is a primary intumescent ingredient for many fire-resistant coating systems. When heated, flakes expand, forming a thick char layer that insulates the substrate and slows heat transfer. That expanded char also reduces oxygen diffusion and helps suppress flame propagation.

Key performance parameters to evaluate when selecting expandable graphite for coatings include expansion ratio (measured under defined test conditions), expansion onset temperature, particle size and flake integrity, ash and acid residues, and dispersion behavior in the coating matrix. Particle size affects coating smoothness and application properties; finer fractions may improve surface finish but require careful dispersion to avoid viscosity increase.

Compatibility testing with binders (epoxy, acrylic, alkyd, water-based systems) and other additives is essential. Formulators should request multi-lot COA, PSD charts, and small pilot samples to run film formation, adhesion, and fire-rating tests (e.g., ASTM or EN standards relevant to the market).

Our team has resumed work after the holiday break and is ready to support technical validation and sample supply. Contact us to request technical datasheets, expansion charts, or pilot samples.