Thermoplastic Polyurethane Flame Retardant Composition

The patent employs a composite flame retardant system combining metal hydroxides (Al(OH)3, Mg(OH)2), phosphorus-containing compounds (phosphates, phosphonates), and nitrogen-containing compounds (melamine, cyanuric acid). This multi-component composite approach creates synergistic effects where each component contributes to flame retardancy through different mechanisms (endothermic decomposition, radical scavenging, char formation), achieving adequate flame protection while reducing the overall filling level required compared to single-component systems, thereby preserving mechanical properties

The patent optimizes the particle size parameters of the metal hydroxides and other solid fillers to improve processability. By controlling particle size distribution and using appropriately sized particles, the composition achieves adequate flow properties and processability during manufacturing while maintaining the necessary flame retardant filling levels. The synergistic flame retardant system also allows for reduced total filler content, further improving processing characteristics

The patent uses phosphorus-containing compounds as intermediary substances that work synergistically with nitrogen-containing flame retardants. The phosphorus compounds promote char formation and stabilize the flame retardant mechanism, reducing the reliance on nitrogen-containing compounds and thereby minimizing the release of toxic gases like HCN and nitrogen oxides while maintaining adequate flame protection. The phosphorus-nitrogen synergy allows for reduced nitrogen content in the formulation