Antimony trioxide is the application of the earliest flame retardants, suitable for epoxy, polyurethane, neoprene, polystyrene, polyvinyl chloride, polyester, etc, when used alone, dosage wants big, flame retardant poor effect (unless flame retardant content non-halogen), when R. H X and halogen hydrates (when) and there is good coordination effect, flame retardant effect obviously improved.