Tobias Moss, Budenheim, presented a new liquid organic phosphorus PIN FR for rigid polyurethane foam, to be commercialised in 2022. The liquid form, soluble in the foam polyol, ensures compatibility with existing processes and machinery and good dispersion. Use at c. 2% loading ensures UL 94 HB (horizontal burn self-extinguishing). Foaming (bubble size) and foam ageing are comparable or better than with TCPP (chlorinated FR, current standard FR for PUR foam). Budenheim also offer a solid APP (ammonium polyphosphate) formulation for foams, achieving UL 94 HB at 5% loading. The solid formulation poses challenges of deposition and redispersion during storage and increases viscosity, posing difficulties for processing, requiring further additives such as stabilisers. The solid and liquid formulations show synergies in combination, including in flexible PUR foams.