... fireproofing additive in expansive fireretardant coating and fire retardan Ammonium polyphosphate(APP) :a. molecular formula: NH4PO3n, n50, b. ... water-solubility less than 2g/100ml. c. excellent fire retardant effect: ... an essential fireproofing additive in expansive fireretardant coating and fire retardants, used in architecture, shipping, cable field ...