Phosphorus and Nitrogen Flame Retardants (PFRs and NFRs)

Phosphorus and nitrogen flame retardants, abbreviated as PFRs and NFRs, are more eco-friendly than halogenated fire retardants. During the combustion process, the PFRs produce phosphoric anhydride or phosphoric acid, which can facilitate the dehydration and carbonization of combustible materials. Then, the production of inflammable gases can be prevented or reduced.

The PFRs are halogen-free flame retardants. Additionally, the combustible materials are covered with glass-like melts during the pyrogenic decomposition of phosphoric anhydride. In this way, the oxidation process is accelerated to form carbon dioxide and then provide a fire-retardant effect.

The NFRs are also non-halogenated flame retardants. The nitrogen compounds can react with combustible materials to facilitate the cross-linking of polymer chains, and then lower the decomposition temperature of combustible materials. The non-flammable gas produced can dilute the inflammable gases.