Calcined muscovite mica tape backed with fibre glass fabric
Mica tapes for fire-resistant cables are reinforced with high temperature resistant silicone resin. The resin is there to ensure mica cohesion and mica adhesion to its support. All together the various components offer effective fire resistance with zero halogen emission.
In the particular case of muscovite, the ore is heat treated at a temperature of around 450°C in order to take out the water of crystallization and by doing so, stabilize its mechanical properties.
Once treated, muscovite mica paper is a better electrical insulator than phlogopite mica paper. So muscovite mica paper will be chosen in the case of applications where dielectric strength is favoured to high temperature.