A melamine salt of pentaerythritol phosphate showed to be an effective PIN FR in polypropylene, with less toxic fire gases than neat PP. Phosphoric acid, pentaerythritol and melamine were react-ed at 4:1:3 ratio, then extruder mixed into polypropylene at 0 – 25%. With 20% loading UL94-V0 (4 mm) was achieved, LOI was increased by 72%, peak heat release rate was reduced by 82% and toxicity of combustion gases (FED: fractional effective dose) was reduced by 39% (compared to neat PP). The fire performance tests were repeat-ed after one year, with the same results, showing that the PIN FR is stable in the PP compound.
“Combustion toxicity of polypropylene containing melamine salt of pentae-rythritol phosphate with high efficiency and stable flame retardancy performance”, G. Makhlouf et al., Process Safety and Environmental Protec-tion (2020), https://doi.org/10.1016/j.psep.2020.04.012