Synergy with Antimony Trioxide

Figure 4.27 Mechanism for endothermic antimony trioxide (ATO) synergy with halogen flame retardants.

Antimony trioxide has a synergistic effect with most halogenated FRs. It is also used in plasticized PVC because of its synergy with chlorine. Antimony oxide should not be used if translucency is required. In some cases ferric oxide is used in its place, for similar physical properties but improved electrical properties. It has been shown by extensive research to be non-carcinogenic. For polymers apart from PVC. a 50% replacement of antimony trioxide is possible with virtually all polymer systems. In particular with both plain and glass-reinforced nylons, excellent flame retardation can be achieved with a suitable combination of zinc sulphide and melamine cyanurate, eliminating both halogens and antimony trioxide. 

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