Flame-retardant Mechanism of Magnesium Hydroxide

When the magnesium hydroxide is heated in 340?-490?, it will decompose and assimilate the heat on the surface of inflamer. Therefore, it plays a role of inflaming retarding. At the same time, it will releases large quantities of moisture to attenuate oxygen gas on the surface of inflamer. And then, it will generate the active magnesium oxide. This active magnesium oxide will stick to surface of inflamer, it can further prevent burning.

In the second place, during the whole inflaming retarding process, not only it won’t produce any hazardous substance, but also it can absorb large amounts of smoke and noxious gas produced by burning plastics, rubber and other macromolecule. The active magnesium oxide can constantly absorb the residues which did not be burned completely. Therefore, the combustion can be stop, and it can eliminate smoke and molten drop. So, it is a kind of rising environmental inorganic flame retardant.

According to the chemical component, the fire retardant can be divided into the organic flame retardant and the inorganic flame retardant. And the organic flame retardant can be divided into two series: halogenated and phosphor. Because the the organic flame retardant exists some defects, such as smoke, high toxicity and so on. It is replaced by inorganic flame retardant step by step.

The main breeds of inorganic flame retardant are magnesium hydroxide, aluminium hydroxide, jewellers putty, antimony oxides, molybdenum oxide, red phosphorus, zinc borate, ammonium molybdate and so on. Among these, the magnesium hydroxide and aluminium hydroxide can take a part in padding besides inflaming retarding, because they has large heat absorption. What’s more, the H2O they produced can not cut off from the air. After the decomposed, the oxide they produced is heat resisting material. In addition, they never produces corrosive gas and smoke, and have the characteristics of non-toxic, non-volatile, effect lasting and so on.

At present, the dosage of aluminium hydroxide is larger in domestic. With the temperature of high polymer processing increasing, the aluminium hydroxide is easy to disintegrate and reduce flame retardant efficiency. Therefore, the magnesium hydroxide is replacing aluminium hydroxide gradually. Compared with aluminium hydroxide, the magnesium hydroxide has a lot of advantages.