Intumescent-flame protection

Intumescent Coatings

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

Composition of an intumescent flame retardant system:

1. "Carbon" donors (e.g. poly alcohols such as starch, pentaerythrite)
2. Acid donors (e.g. ammonium polyphosphate)
3. 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 polyalcohols)

4. Gas formation by the propellant (e.g. melamine)

5. Foaming of the mixture

6. Solidification through cross-linking reactions

The picture below shows how the foam looks in the end. This coating expanded from a 1 mm layer to a 100 mm foam.