In order to increase the flame resistance of polymer materials, they are mainly used in polymer materials such as plastics, rubber, fibers and so on. Most of these materials can be burned. Plastics, in particular, must be used in transportation, construction, electrical equipment, aviation, space flight and so on. It is urgent to solve the problem of its anti-combustion. The use of flame retardants should generally meet the following conditions: do not reduce the physical properties of polymer materials, such as heat resistance, mechanical strength, electrical properties; decomposition temperature should not be too high, but can not be decomposed at processing temperature; good durability; good weather resistance; low price.

Generally speaking, organic flame retardant has a good affinity. In plastics, bromine flame retardant occupies an absolute advantage in organic flame retardant system. Although there are many "criticisms" on environmental protection, it has been difficult to replace other flame retardant systems.

Among non-halogen flame retardants, red phosphorus is a better flame retardant, which has the advantages of low additive, high flame retardant efficiency, low smoke, low toxicity and wide use. Red phosphorus is compounded with inorganic flame retardants such as aluminium hydroxide and expansive graphite to form composite phosphorus/magnesium, phosphorus/aluminium, phosphorus/graphite and other non-halogen flame retardants, which can be used as flame retardants. The volume of plastic products is greatly reduced, thus improving the processing performance and physical and mechanical properties of plastic products. However, ordinary red phosphorus is easy to oxidize and absorb moisture in the air, easy to cause dust explosion, transport difficulties, poor compatibility with polymer materials and other defects, the application scope is limited. In order to make up for this deficiency, the encapsulation process of microcapsules can be used to make it into red phosphorus microcapsules. Microencapsulated red phosphorus not only overcomes the inherent drawbacks of red phosphorus, but also has high efficiency and low smoke. It does not produce toxic gases in processing. Its dispersibility, physical, mechanical properties, thermal stability and flame retardancy are improved and improved.