抄録
Ammonium polyphosphate forms II, V, and VI have been prepared by new preparation processes using ammonium orthophosphate, urea and/or phosphorus pentaoxide as starting materials. The preparation processes are very useful for a large scale preparation in a factory. These crystal phases of APP showed flame retardant effect to organic polymer materials. The order of flame retardation effect among the phases was V > II > VI ≥ I.
