Synthesis And Applications Of P, N-series Flame Retardants

The composite materials are widely used nowadays and their safety are much more concerned. At the same time the needs of flame retarded materials and flame retardant grows rapidly. Though the classical halide fire retarding agents have good performance, most of them give out heavy smoke with poisonous gas when burning. The flame retardant is developing toward high effective, no halogen, and light smoke in next years.The intumescent flame retardant is composed by acid source, carbon source and gas source. The fire retarding elements are Nitrogen and Phosphorous. When the flame retarded materials composed by these compounds are burned, the intumescent layer can insulate thermal, inhibit smoke and prevent producing molten drop, so the flame retarding performance is high.The Tripolycyanamide(melamine) salt(including melamine phosphate. melamine pyrophosphate and melamine cyanurate )is consisted of acid source and gas source and their fire retarding performance is high .These compounds have been widely used abroad and have not been produced in our country yet.In this paper, melamine phosphate and melamine cyanurate were prepared in solvent. The effect of reaction temperature, time, and material ratio on each reaction was discussed. The content of P in melamine phosphate and the retained acid in melamine cyanurate were analyzed. The TGA spectra of the two compounds were made.Melamine pyrophosphate can synthesized by three means:(l) prepared by pyrophosphoric acid and melamine in low temperature. (2) prepared by pyrophosphate and melamine in acid. (3) prepared in solid phase. Each of the results is analyzed and the optimum preparing technology is chosen. At last, the solid phase synthesis is determined as the best way to produce melamine pyrophosphate.All of the compounds above mentioned have been successfully applied in practical production. Most of them, to select a optimum equipment is the key toproduce melamine pyrophosphate. The scaling effect on their quality and yield is little.The implemental experiments were studied when those compounds are used in material such as Nylon 66, Nylon 6,PET and other polymers. The results shows that MR MPY, MCA are indeed excellent flame retardant.