The flame retardant can be classified into a halogen-based flame retardant, a phosphorus-based flame retardant, a nitrogen-based flame retardant, a phosphorus-halogen flame retardant, and a phosphorus-nitrogen flame retardant according to the flame retardant element contained therein.
During the pyrolysis process, the halogenated flame retardant decomposes X and HX which capture and transmit combustion radicals. HX can dilute the combustible gas generated during the cracking of combustible materials and block the contact of combustible gas with air.
Phosphorus-based flame retardants produce phosphoric anhydride or phosphoric acid during combustion, which promotes dehydration and charring of combustibles and prevents or reduces the generation of combustible gases. Phosphoric anhydride also forms a glass-like melt on the surface of the combustible material during pyrolysis, which causes it to oxidize to form carbon dioxide, which acts as a flame retardant.
In the nitrogen-based flame retardant, a nitrogen compound and a combustible substance act to promote cross-linking to form charcoal, reduce the decomposition temperature of the combustible material, and generate a non-combustible gas, thereby functioning to dilute the combustible gas.
Phosphorus-halogen flame retardant and phosphorus-nitrogen flame retardant mainly achieve the flame retardant effect through the synergistic effect of phosphorus-halogen and phosphorus-nitrogen, and have the dual effects of phosphorus-halogen and phosphorus-nitrogen, and the flame retardant effect is better. .