Silicone Bonded Mica Sheet

What Silicone Does for Mica

85% to 90% premium mica or phlogopite is impregnated with 10% to 15% high-temperature silicone resin to create silicone resin-bonded mica sheets. The mica is thermally cured at temperatures between 150°C and 200°C after being shaped into sheet material and completely impregnated with resin. The silicone resin enables the cured material to maintain exceptional flexibility, in contrast to the stiff thermosetting polymers utilised in traditional mica sheets. This material has good thermal and electrical conductivity and is sufficiently soft to be folded, wrapped, and moulded into gaskets without splitting.

Where Flexibility Wins

Curved surfaces and enclosed areas are suitable for this grade. It protects engine compartments, wraps coils and cables, acts as a heat barrier in electric car battery packs and fits into furnace shells that are inaccessible to rigid boards. Because the silicone binder increases chemical resistance to oils, solvents, and mild acids, silicone-bonded phlogopite mica sheets can be used continuously at temperatures as high as 700°C. Because of its considerable dielectric strength at high temperatures (often 18 to 23 kV/mm) and low thermal conductivity (0.2 to 0.6 W/mK), it provides both thermal and electrical insulation. Rolls that are 25 to 50 meters long and 500 to 1000 mm wide are used in most wrapping and die-cutting operations.

A Few Practical Notes

The bonding agent is one crucial aspect of storage. The sheets should be maintained level or loosely rolled and out of direct sunlight because silicone deteriorates when exposed to UV radiation and tight creases might weaken the connection. The material can be strengthened with fibreglass fabric and put through procedures like die-cutting and machining when tear resistance is crucial. We always give the same advice to customers who ask about this variety of flexible sheets: handle the bonding layer carefully because it is the source of the material's flexibility, and store them at temperatures between 15°C and 30°C and a relative humidity of 30% to 60% (aiming for a shelf life of about 24 months).