For Class B1 rigid foam insulation boards, adding 10–14 parts of red phosphorus flame retardant can reduce the FIGRA value to below 100 W/s while maintaining a closed-cell rate of over 87%. Compared to aluminum hydroxide-based systems, this results in annual savings of approximately $20,000 to $30,000 in flame retardant costs. Silver-coated red phosphorus is available in both powder and paste forms, making it suitable for both manual and continuous production lines.
As yellow phosphorus prices navigate a period of post-decline volatility, our latest market analysis explores how shifting raw material costs are triggering a critical industry 'shakedown' for downstream phosphorus-based flame retardants.
Inorganic flame retardants such as ATH and MDH require high loading levels in TPU to achieve the required flame retardancy rating; however, high loading levels severely degrade the material’s mechanical properties and flexibility. Through nano-blending strategies—such as the physical barrier effect of nano-clay layers and the carbonization mechanism of expandable graphite—it is possible to enhance flame retardancy while reducing the amount of inorganic additives, thereby providing an alternative to phosphorus-based flame retardants for TPU.