Charmor is Perstorp's brand of micronized polyols used for producing high performance intumescent coatings. The Charmor products serve as the carbon donor in intumescent coatings, which in conjunction with a blowing agent and acid source produce a char layer when exposed to fire. This Char layer protects the underlying substrate, limiting structural damage and facilitating the evacuation of the impacted structures.
Overall, intumescent coatings work as follows:
- The thermoplastic coating film melts when exposed to the heat of fire, allowing further chemical reactions to take place in the soft matrix.
- The acid donor (ammonium polyphosphate) decomposes to form polyphosphoric acid.
- Polyphosphoric acid reacts with Charmor to form an inorganic/organic ester
- The blowing agent (melamine) releases gases causing the ester to create a foam that forms the insulating barrier which adheres to the substrate
- The ester decomposes to form a tough carbon matrix