Antimony trioxide is a white crystalline powder with a melting point of 655°C and a boiling point of 1550°C. It is soluble in concentrated hydrochloric acid, sulfuric acid, alkali solutions and hot tartaric acid solutions. Slightly soluble in water, dilute nitric acid and dilute sulfuric acid, it is mainly used as a pigment, flame retardant, mordant, catalyst, and can also be used to synthesize antimony salts.
Antimony trioxide is a widely used flame retardant:
Antimony trioxide is the earliest used flame retardant, often combined with other When flame retardants and smoke suppressants are used together, synergistic effects can be produced between each component. In the early stages of combustion, antimony trioxide first melts, forming a protective film on the surface of the material to isolate the air, and reduces the combustion temperature through internal endothermic reactions. Antimony trioxide is vaporized at high temperatures and dilutes the oxygen concentration in the air, thereby acting as a flame retardant. In fact, antimony trioxide is a commonly used flame retardant synergist.
Antimony trioxide is a widely used additive flame retardant, suitable for general flame retardant of polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyester, epoxy resin, polyurethane and other plastics. fuel. When used alone, the flame retardant effect is low. When used together with phosphate esters, chlorine-containing compounds (such as chlorinated paraffins, polychlorinated biphenyls, perchlorcyclodecane, etc.), and bromine-containing compounds (such as hexabromobiphenyl, hexabromobenzene) , has a good synergistic effect, and the flame retardant efficiency is significantly improved. When antimony trioxide is used together with chloride or bromide, antimony chloride or antimony bromide is generated. They are reactive and volatile substances. In the solid state, they can promote the movement of halogens and the formation of carbides. In the gaseous state, they can Capturing free radicals, these reactions contribute to flame retardancy. Often, zinc oxide, sodium hydroxide, etc. are used as synergists of brominated flame retardants in plastic fire protection systems.