Magnesium oxide formed by decomposition is a good refractory material, which can also help improve the fire resistance of synthetic materials. At the same time, the water vapor it emits can also be used as a smoke suppressant. Magnesium hydroxide is recognized as an excellent flame retardant with triple functions of flame retardance, smoke suppression and filling in the rubber and plastic industry. Widely used in rubber, chemical, building materials, plastics and electronics, unsaturated polyester and paint, coatings and other polymer materials. In particular, it is used for coating of wind deflectors for mines, PVC core conveyor belts, flame-retardant aluminum-plastic panels, flame-retardant tarpaulins, PVC wire and cable materials, cable sheaths for mines, flame-retardant, smoke-suppression and anti-static properties of cable accessories. It can replace aluminum hydroxide and has excellent flame retardant effect. Compared with similar inorganic flame retardants, magnesium hydroxide has better smoke suppression effect. Magnesium hydroxide has no harmful substances emitted during production, use and disposal, and can also neutralize acidic and corrosive gases generated during combustion. When used alone, the dosage is generally 40% to 60%.
Why can magnesium hydroxide flame retardant be widely used?
At present, there is a large amount of aluminum hydroxide in China. However, as the processing temperature of the polymer increases, aluminum hydroxide is liable to decompose and reduce the flame retardant effect. Magnesium hydroxide has the following advantages over aluminum hydroxide:
1. The thermal decomposition temperature of magnesium hydroxide reaches 340 ° C, which is 100 ° C higher than aluminum hydroxide, which is conducive to the improvement of plastic processing temperature, accelerates the extrusion speed, improves the plasticization effect, shortens the molding time, and has a high surface gloss. Surface defects will be generated, and at the same time, it has a strong peel strength.
2. Uniform particle size distribution, good compatibility with the substrate, and small impact on the mechanical properties of the product.
3. Magnesium oxide formed after the combustion and dehydration of magnesium hydroxide is a high-strength and high heat-resistant material, which can be used as a protective wall to isolate fire sources and toxic and harmful gases. Quickly neutralize the acid gases SO2, NOx, CO2, etc. generated during the plastic combustion process.
4. Magnesium hydroxide has high decomposition ability, high flame retardant efficiency, strong smoke suppression ability, low hardness, and low friction to the equipment, which helps to extend the life of the equipment.
5, the price is low, magnesium hydroxide is half the price of aluminum hydroxide, the filling amount is large, which can greatly reduce the cost of the product.
Flame retardant mechanism of magnesium hydroxide flame retardant:
Magnesium hydroxide decomposes when heated (340-490 degrees) and absorbs the heat of the surface of the combustible to flame retardant effect; at the same time, a large amount of water is released to dilute the oxygen on the surface of the combustible, and the active magnesium oxide formed by the decomposition adheres to the surface of the combustible and further prevents The burning progressed. Magnesium hydroxide not only does not produce any harmful substances in the entire flame retardant process, but its decomposition products can also absorb a large amount of harmful gases and fumes generated by the combustion of polymers such as rubber and plastic while being flame retardant. The incompletely burned melting residue is an emerging environmentally friendly inorganic flame retardant, which eliminates smoke and stops molten droplets while stopping combustion quickly.