Magnesium Hydroxide (MH), the molecular formula is Mg(oH)2, the relative molecular mass is 58.33. White powder with hexagonal amorphous flake crystals. Magnesium hydroxide is decomposed into magnesium oxide water by heating. The initial decomposition temperature is 340℃. When it reaches 430℃, the decomposition speed is accelerated. At 490℃, the decomposition is complete. The decomposition endothermic energy is 0.” kJ/g (44.8kJ/ mol). The raw materials for producing magnesium hydroxide flame retardant are natural mineral raw materials liquid raw materials. The mineral raw materials are mainly magnesium-containing non-metallic minerals, including brucite, magnesite, dolomite, etc.; the liquid raw materials are seawater, Salt lake brine, mainly underground brine.

Magnesium hydroxide, as a flame retardant filler for polymer-based composite materials, has been used in plastics, rubber cables. The flame retardant mechanism of magnesium hydroxide is considered to be:

1) It has a much larger heat capacity than polymers, so it can absorb a lot of heat before it is decomposed by heat.

2) A large amount of water released by thermal decomposition (the dehydration amount is 30.9%) absorbs a lot of heat (about 1370J/g), thereby reducing the actual temperature of the flame on the surface of the polymer material, slowing its degradation rate, generating combustible gases The amount is reduced.

3) A large amount of water vapor released during the decomposition process can cover the flame, reduce the oxygen concentration in the air on the combustion surface dilute the flammable gas.

4) Mgo produced after decomposition is a good refractory material, covering the surface of the polymer to block heat conduction heat radiation, thereby improving the ability of the polymer to resist flame, play a role in isolating air preventing combustion; the highly active MgO layer Adsorbs many substances (including free radicals carbon), can promote the carbonization of polymer materials, promote the rapid formation of a carbonized layer during combustion.