3. Inorganic or mineral flame retardants

3.1 Mechanisms of action

The number of mineral compounds used as RF that can decompose with heat is relatively small (table 2 ). They must decompose endothermically in a relatively low temperature range, between 150°C and 500°C, which is not very common for minerals. The intensity of decomposition enthalpy is therefore a key parameter in their performance. Even so, very high incorporation rates may be required to pass reaction to fire tests (up to 70% by mass in some cases).

These RFs must be compatible with polymer forming processes, and in particular must not decompose at the temperature of mixing with the polymer melt in processes such as extrusion or injection for thermoplastics. These compounds...