Antimony compounds can also be added to the material of low smoke flame retardant cable. Antimony compounds are not flame retardants per se, but a kind of flame retardant synergist, which is often used in combination with halides. At high temperature, antimony trioxide reacts with halides to generate antimony trihalide or antimony oxyhalide, and its flame retardant principle is gas-phase flame retardant principle: antimony trihalide vapor can stay in the combustion zone for a long time, which can dilute flammable gases, and the density of antimony trihalide vapor is high, covering the polymer surface, which can play the role of heat insulation and oxygen isolation, which is very effective for inhibiting the combustion of materials; The decomposition of antimony oxyhalide is an endothermic reaction, which can effectively reduce the temperature and decomposition rate of flame retardant materials; The surface effect of liquid and solid antimony trihalide particles can reduce the flame energy; Antimony trihalide can promote the carbonization reaction of condensed phase, and relatively delay the thermal decomposition and oxidative decomposition of materials that generate combustible gas, and the generated carbon layer can prevent combustible gas from escaping into the flame zone and protect the underlying materials from being destroyed.