Current practice and recent commercial developments in flame retardancy of polyamides

This review presents the currently used or promising flame retardant systems for the aliphatic polyamides. The largest applications are in electrical parts, with smaller usage in automotive and textiles. A polycyclic chlorohydrocarbon, DECHLORANE PLUS, is employed in low smoke formulations. Decabromodiphenyl ether has major use in polyamide 6. Alternative brominated additives include decabromodiphenylethane, polybrominated phenylindane, polymeric dibromophenylene oxide, polybrominated polystyrene and oligomeric glycidyl ethers of tetrabromobisphenol A, and polypentabromobenzyl acrylate. In non-reinforced polyamide 6, melamine cyanurate is effective. With glass reinforcements, some melamine pyro- or polyphosphates are useful. Polyamide 6 can be flame retarded with high loadings of magnesium hydroxide. Stabilized and coated red phosphorus is used in Europe and the Far East. A recent development is the use of aluminum dialkylphosphinate. In textile fiber, there has been some development of a built-in phosphinate. Polyamide fabric can be flame retarded with a thioureaformaldehyde resin finish.