Halogen-free flame retardants of phosphite esters have the following properties:
Flame retardancy and antioxidant synergy: Some phosphites have both flame retardancy and antioxidant functions. For instance, when triphenyl phosphite (TPP) is used in combination with halogen-based flame retardants, it can simultaneously exert flame retardancy and antioxidant effects, and also has light stabilizing functions.
Thermal stability and chemical stability: Phosphite ester flame retardants are not prone to decomposition at high temperatures and have good thermal stability. Meanwhile, the P-O bonds in its molecular structure have a tendency to transform into PO bonds, making the molecule itself tend to be stable and providing impetus for subsequent reactions.
Water resistance and moisture resistance: Due to the low hygroscopicity and low smoke emission of phosphorus, phosphite ester flame retardants usually have good water resistance and moisture resistance.
Compatibility and processability: Phosphite ester flame retardants have good compatibility with polymer materials and are easy to process. For instance, tris (dipropylene glycol) phosphite (P430) is a phosphorus-containing polyhydroxyl reactive flame retardant. Its terminal hydroxyl group can cross-link with isocyanate (TDI), demonstrating unique hot-melt re-curing properties and permanent flame retardancy. Moreover, it can also enhance the adhesion between foam and fabric.
Performance advantages in specific application fields: Phosphite ester flame retardants exhibit excellent flame retardant effects in fabrics such as polyurethane foam plastics, non-woven fabrics, and artificial leather. For instance, tris (dipropylene glycol) phosphite does not contain phenol, bisphenol A or nonylphenol, and has halogen-free reactive flame retardant properties. It is widely used in polyurethane foam, which can prevent the core from burning and resist yellowing, and exert a significant halogen-free flame retardant synergistic effect.
