Application of flame retardant

The flame retardant can not only retard the flame, but also prevent smoke, no droppings and toxic gases,


Scope of application:


Flame retardant mechanism of thermosetting plastics, thermoplastics, synthetic rubber, coatings, building materials and other industries, fire retardant or fire retardant: functional additives endowed with flame retardant properties of flammable polymers; It is mainly suitable for mortar and cement component products with flame retardant demand to delay or prevent the combustion of buildings. It is difficult to ignite because of the increase of ignition time and self extinguishing. The fabric can achieve strong flame retardancy after soaking in this product.


Flame retardants exert their flame retardancy through several mechanisms, such as endothermic effect, covering effect, inhibition of chain reaction, asphyxiation effect of non combustible gas, etc. Most of the flame retardants achieve the purpose of flame retardancy through several mechanisms.


Endothermic effect


The heat released by any combustion in a short time is limited. If part of the heat released by the fire source can be absorbed in a short time, the flame temperature will be reduced, the heat radiated to the combustion surface and acting on the cracking of vaporized combustible molecules into free radicals will be reduced, and the combustion reaction will be inhibited to a certain extent. At high temperature, the flame retardant has a strong endothermic reaction, which can absorb part of the heat released by combustion, reduce the temperature of the surface of the fuel, effectively inhibit the generation of combustible gas and prevent the spread of combustion. The flame retardant mechanism of flame retardant is to increase the heat capacity of polymer to absorb more heat before reaching the thermal decomposition temperature, so as to improve its flame retardant performance. This kind of flame retardants give full play to their heat absorption characteristics when combined with water vapor, and improve their own flame retardancy.


Covering effect


After adding flame retardants in combustible materials, flame retardant can form glass or stable foam covering at high temperature, and isolate oxygen, which has the function of heat insulation, oxygen isolation and preventing flammable gas from escaping outward, so as to achieve the purpose of flame retardancy. For example, organic phosphorus flame retardant can produce more stable cross-linked solid substance or carbonized layer when heated. On the one hand, the formation of carbonization layer can prevent the polymer from further pyrolysis, on the other hand, it can prevent the thermal decomposition products from entering the gas phase to participate in the combustion process.


Inhibitory chain reaction


According to the chain reaction theory of combustion, free radicals are needed to maintain combustion. The flame retardant can act on the gas phase combustion zone to capture the free radicals in the combustion reaction, so as to prevent the spread of flame, reduce the flame density in the combustion zone, and finally reduce the combustion reaction speed until the end. When the polymer is decomposed by heat, the flame retardant also volatilizes. At this time, the halogen-containing flame retardant and thermal decomposition products are in the gas-phase combustion zone at the same time, the flame retardant can capture the free radicals in the combustion reaction, so as to prevent the spread of the flame, reduce the flame density in the combustion zone, and finally reduce the combustion reaction speed until the end.


Asphyxiation of incombustible gases


When the flame retardant is heated, it decomposes into incombustible gas and dilutes the concentration of combustible gas decomposed from combustible to below the lower limit of combustion. At the same time, it can also dilute the oxygen concentration in the combustion zone to prevent the combustion and achieve the flame retardant effect.