Introduction Flame Retardants

Inorganic flame retardants works physically, which has low efficiency and large amount of addition. It has a certain impact on the performance of materials. However, due to the low price it can be used in low-end products with low requirements of performance, such as plastics PE, PVC, etc. Take aluminum hydroxide (ATH) as an example.It will undergo dehydration and decomposition after being heated up to 200 ℃. The decomposition process absorbs heat and water evaporation, so as to inhibit the temperature rise of the material, reduce the temperature of the material surface, slow down the speed of thermal cracking reaction. At the same time, water vapor can dilute the oxygen concentration and prevent combustion.The alumina produced by decomposition is attached to the material surface, which can further inhibit the spread of fire.

Organic halogen flame retardants mainly adopt chemical way. Its efficiency is high and the addition is samll with good compatibility with polymers. They are widely used in electronic castings, printed circuit boards and other electrical components. However, they will emit toxic and corrosive gases, which has certain safety and environmental protection problems. Brominated flame retardants(BFRs) are mainly kind halogenated flame retardants. The other one is chloro-series fire retardants(CFRs). Their decomposition temperature is similar to that of polymer materials. When polymers are heated and decomposed, BFRs also begin to decompose, enter the gas phase combustion zone together with thermal decomposition products, inhibit the reaction and prevent flame propagation. At the same time, the released gas covers the surface of the material to block and dilute the oxygen concentration, and finally slow down the combustion reaction until it is terminated. In addition, BFRs are usually used in combination with antimony oxide(ATO). ATO itself does not have flame retardancy, but can act as a catalyst to accelerate the decomposition of bromine or chlorine.

Organic phosphorus flame retardants(OPFRs) works both physically and chemically, with high efficiency and the advantages of low toxicity, durability and high cost performance. In addition, it can also improve the processing fluidity of the alloy, provide plasticizing function and excellent performance.With the higher requirements of environmental protection, OPFRs are gradually replacing BFRs as mainstream products.

Although the addition of FR can not make the material fully resist the fire, it can effectively avoid the "flash burn" phenomenon, reduce the occurrence of fire and win valuable escape time for people in the fire scene. The strengthening of national requirements for flame retardant technology also makes the development prospect of FRs more broad.