Flame retardant is a kind of additive that can prevent the ignition or flame propagation of polymer materials. According to its use method, it can be divided into additive type and reactive type. Additive flame retardant is added into materials in the process of plastic processing, which is mostly used in thermoplastic plastics. Reactive flame retardants are chemically bonded to the polymer molecular chain as monomers in the process of polymer synthesis. They are mostly used in thermosetting plastics. Some reactive flame retardants can also be used as additive flame retardants.