Flame retardant mechanism of magnesium hydroxide, an inorganic flame retardant

　　When magnesium hydroxide is heated at 340℃-490℃, it will decompose and absorb the heat on the surface of the combustor, thus playing the role of flame retardant.

　　At the same time, a large amount of water will be released to dilute the surface of the combustion oxygen, the decomposition of the active magnesium oxide will adhere to the surface of the fuel, further prevent combustion.

　　Second, in the process of the flame retardant type magnesium hydroxide is not only does not produce any harmful substances, and the product of the decomposition of magnesium hydroxide in flame retardant effect at the same time, also can absorb plastic and rubber polymer smoke and harmful gas, such as active magnesium oxide can be constantly absorbing incomplete combustion melting residues, and then make the burning soon stopped and eliminate smoke and prevent drop, is a new kind of environmentally friendly inorganic flame retardants.

　　Flame retardants can be divided into organic flame retardants and inorganic flame retardants according to their chemical composition.

　　Organic flame retardants are divided into halogen and phosphorus series.

　　Organic flame retardants are gradually replaced by inorganic flame retardants due to their defects such as high smoke and high toxicity of decomposition products.

　　The main varieties of inorganic flame retardants are magnesium hydroxide, aluminum hydroxide, tin oxide, antimony oxide, molybdenum oxide, red phosphorus, zinc borate, ammonium molybdate and so on.

　　Of magnesium hydroxide and aluminum hydroxide for decomposition heat absorption capacity is big, and the generated H2O can have the effect of the air, after decomposition generated oxide is high temperature resistant material, magnesium hydroxide and aluminum hydroxide so these two kinds of flame retardants in addition to have the effect of flame retardant, also can have the effect of filling, and have no corrosive halogen gas and harmful gas, smokeless, non-toxic, do not drop, non-volatile, long-term effect, etc.

　　At present, the domestic amount of aluminum hydroxide is more, but with the increase of processing temperature of high polymer, aluminum hydroxide is prone to decomposition, reduce the effect of flame retardant.

　　Therefore, magnesium hydroxide syndrome gradually replaces aluminum hydroxide.

　　Compared with aluminum hydroxide, magnesium hydroxide has the following advantages:

　　The decomposition temperature of magnesium hydroxide is 100℃ higher than that of aluminum hydroxide, reaching 330℃, which is more helpful to improve the processing temperature of plastics, accelerate the extrusion speed and shorten the molding time.

　　The decomposition energy of magnesium hydroxide is high, which is helpful to absorb combustion heat and improve flame retardant efficiency.

　　Magnesium hydroxide and acid have strong neutralization ability, which can quickly neutralize the acidic gas CO2, SO2, NOX, etc. produced in the combustion process of plastics.