Posted on 15/05/2023 in Fire Safety 2023
PIN FR synergies in polyamide

Fire performance synergies are shown between phosphorus PIN flame retardant and different PIN mineral additives. The well-recognised PIN phosphorus flame retardant DEPAL  (aluminium diethyl phosphinate) was tested in injection molded polyamide 6 alone (15%) or with combinations of four different PIN minerals (1 to 5%): magnesium hydroxide (MDH), ammonium polyphosphate, high molecular weight siloxane, boehmite (aluminium oxide hydroxide mineral), zinc borate. Fire performance, mechanical properties and densities of a total of sixteen different formulations were tested. Neat polyamide was UL 94 V-2 and GWI 750°C, but achieved UL 94 V-0 (1.5 mm) and GWI 960°C with DEPAL only. LOI was around 25% higher with DEPAL only (compared to neat polyamide) but was doubled with some synergist combinations, in particular with MDH. Smoke density with DEPAL only was around half that with neat polyamide, but could be significantly further reduced by inclusion of synergists. Similarly, carbon monoxide emissions, reduced by DEPAL alone, were further reduced with synergists. Combinations of DEPAL with MDH, and with MDH plus other synergists offer high LOI and achieve the low smoke density requirement of the EU railway standard R22-EN45545.

“Investigation of the Fire Performance of Polyamide 6‑Based Composites with Halogen-free Flame Retardants and Synergistic Materials”, T. Uysalman et al., CS Omega 2022, 7, 33, 28885–28895

Share This