Acting principle: formation of a voluminous, insulating protective layer through carbonization and simultaneous foaming

Composition of an intumescent flame retardant system:

  • "Carbon" donors (e.g. poly alcohols such as starch, pentaerythrite)
  • Acid donors (e.g. ammonium polyphosphate)
  • Propellants (e.g. melamine)
 
Processes of intumescent mechanism:
1. Softening of the binder/polymer (e.g. PP)
2. Release of an inorganic acid (e.g. ammonium polyphosphate)
 
3. Carbonization (e.g. of poly alcohols)
 
4. Gas formation by the propellant (e.g. melamine)
 
5. Foaming of the mixture
6. Solidification through cross-linking reactions