Hebei Messi Biology Co., Ltd. said that there are currently two production processes for magnesium hydroxide. One is refined from Qinghai Salt Lake brine, which has high purity and few impurities. The second is made from selected natural brucite ore through advanced production technology. The purity of the product is not as good as the former, and the molecular formula is Mg(OH)2. Brucite single crystals are in the shape of thick plates, often in the form of flake aggregates, and sometimes in the form of fibrous aggregates, called Nemalite or brucite asbestos. The color is white to light green, and those containing manganese or iron are reddish-brown. The color change of brucite depends on the content of mixed materials. For example, variants containing iron and manganese impurities appear yellow or brownish-red. The cleavage surface has a pearlescent luster, the fresh crystal surfaces and fracture surfaces have a glassy luster, and the fiber brucite has a silky luster.
The Mohs hardness of magnesium hydroxide is 2.5, the specific gravity is 2.3-2.6, and the refractive index is 1.56. It begins to decompose at 330°C, producing magnesium oxide and water. The decomposition rate is fastest at 430°C, and the decomposition is completed at 490°C. Soluble in acid and ammonium salt solution, insoluble in water and ethanol. Magnesium hydroxide not only has flame retardant effect but also smoke suppression function. It has many properties better than aluminum hydroxide and is an environmentally friendly inorganic flame retardant. Magnesium hydroxide and aluminum hydroxide decompose to absorb a large amount of heat and produce water, which can insulate the air. After decomposition, the oxides are high-temperature resistant substances, so the two flame retardants can not only play a flame retardant role, but also It can play a filling role and has the characteristics of not producing corrosive halogen gas and harmful gas, non-volatile, long-lasting effect, non-toxic, smoke-free, and non-drip.
Magnesium hydroxide has the following advantages over aluminum hydroxide:
① The thermal decomposition temperature of magnesium hydroxide reaches 330°C, which is 100°C higher than aluminum hydroxide, so it is beneficial to increase the plastic processing temperature, speed up the extrusion speed, and shorten the molding time;
② Magnesium hydroxide has strong neutralizing ability with acids and can quickly neutralize acidic gases SO2, NOx, CO2, etc. produced during the burning process of plastics;
③The enthalpy of the decomposition reaction of magnesium hydroxide becomes high and the heat absorbed is large, which is beneficial to absorbing the heat of combustion and improving the flame retardant efficiency;
④ Magnesium hydroxide has strong smoke suppression ability, low hardness, and low friction on equipment, which helps to extend the life of production equipment.
Application of magnesium hydroxide in rubber plastics
Magnesium hydroxide or activated magnesium hydroxide is widely used as an excellent flame retardant and filler for polymer materials such as PE, PP, PVC, ABS, PS, HIPS, PA, PBT, unsaturated polyester, epoxy resin, rubber, etc. In electronics, unsaturated polyester and paints, coatings and other polymer materials, especially for mining air duct coating cloth, PVC whole core conveyor belt, flame retardant rubber sheet, tarpaulin, PVC wire and cable materials, mining It can replace aluminum hydroxide in the fields of flame retardancy, smoke elimination and antistatic for cable sheaths and cable accessories and has excellent flame retardant effects.
The modified magnesium hydroxide independently developed and produced by Hebei Meixi Biological Co., Ltd. uses specific modifiers and surface modification treatment of magnesium hydroxide through specific process technology. The modified magnesium hydroxide is more evenly dispersed in the resin matrix, thereby making the physical and chemical properties of rubber and plastic products more superior. And the company can modify various types of magnesium hydroxide according to customer requirements to meet the different needs of customers.