Flame retardants in commercial use or development for polyolefins

Polyolefins, used widely in electrical applications, roofing, and automotive parts, have a high heat of combustion and tend to burn with substantial fuel evolution and little char. Since the polyolefins can usually accept high loadings of solid additives, aluminum hydroxide and magnesium hydroxide have found use. At lower loadings, vapor-phase-active flame retardants of the halogen-antimony oxide type have proved useful; older chlorinated types are still in use, and both old and new bromine compounds are widely employed in polyolefins. Much effort has been expended on intumescent phosphorus-based additives and there are some newer ones which show promise.