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.
1)Stop action of thermal de-composite chain reaction under gas phase (Radical trap effect)
2)Sealing action against oxygen under gas phase (Air sealing effect)
3)The formation of carbonaceous char under the solid phase (Air sealing and adiabatic effect)
The above reactions are considered to be as follow;
Examples of Antimony Trioxide Mixture
Type of Polymers
Typical Data (phr)
UL-94(1.6mm)
LOI
PVC
100 phr
DINP
50
Sb2O3
3
V-0
30.4
PE
100 phr
TBA*
15
Sb2O3
5
V-2
26.3
PP
100 phr
DBDPO
20
Sb2O3
10
V-0
26.4
PS
100 phr
DBDPO
10
Sb2O3
10
V-0
27.4
ABS
100 phr
TBA*
24
Sb2O3
10
V-0
33.3
PBT
100 phr
TBA*
16
Sb2O3
7
V-0
27.8
PUR
100 phr
DBDPO
12
Sb2O3
3
V-0
30.7
*Br content, including 50-70% TBA derivative and Oligomer type
Above data is an example of measurements, but are not standards or warranties of performance.