Antimony trioxide itself has no flame retardant function, however, when it is used together with halogenated compounds, the synergistic effect of the mixture creates the flame retardant properties.
Antimony trioxide reacts with halogenated compound and creates the chemical compounds, which generate the flame retardant function, through the following process.
- Stop action of thermal de-composite chain reaction under gas phase (Radical trap effect)
- Sealing action against oxygen under gas phase (Air sealing effect)
- The formation of carbonaceous char under the solid phase (Air sealing and adiabatic effect)
The above reactions are considered to be as follow;