Phosphazene flame retardant
HPCTP, a cyclic phenoxyphosphazene, is a thermally and hydrolytically stable phosphorus-nitrogen flame retardant with favourable electrical properties. Phosphazenes show higher heat distortion temperature compared to aromatic bisphosphates.
HPCTP is designed for use in PC and PC/ABS resins (transparent and coloured applications, including LED). It is effective in PC/ABS at 12-15 wt.%, providing a UL94 V-0 rating, while the oxygen index can reach 33%.
Besides use in PC(/ABS), HPCTP also shows good flame retardancy in epoxy resin. When used in benzoxazine resin glass cloth laminate, the mass fraction is 10% and the flame retardancy can reach a V-0 rating, while the parallel breakdown voltage is 47KV. If used in polythene, the oxygen index of the polythene can reach 30-33.