Modification of Magnesium Hydroxide Introduction
In the production process of HFFR/LSZH compounds, If using un-modified magnesium hydroxide, since its strong polarity and large surface energy, it is easy to re-aggregate during the process when it is used as a flame retardant. At the same time, the magnesium hydroxide powder is hydrophilic, the water can not be completely removed after drying, and it has poor compatibility when added to the polymer material system. Therefore, it is necessary to add a pair of powder modifiers in the process of preparing ultrafine magnesium hydroxide powder to improve the surface activity of the particles, to improve the fluidity and compatibility, and finally improve the performance of magnesium hydroxide in flame-retardant products.
Below are the methods of modification of magnesium hydroxide flame retardant.
- Ultra-fine nano particle
The ultra-fineness of magnesium hydroxide is to pulverize the magnesium hydroxide powder, and take appropriate measures to reduce the particle size as much as possible, or even reach the nanometer level, increase the contact area between the flame retardant and the polymer matrix, and strengthen the magnesium hydroxide. The affinity with the polymer improves the compatibility between the two, achieving the purpose of reducing the dosage and improving the flame retardant efficiency. After the magnesium hydroxide is ultra-fine, it has little wear on the equipment. It can be widely used in polypropylene, polyethylene, polyvinyl chloride, high impact polystyrene, and ABS resin, etc.
- Surface modification of magnesium hydroxide
Due to the ultra-fine magnesium hydroxide, although the contact area with the polymer matrix is increased, its specific surface area is increased. At the same time, it has strong polarity, has a positive charge on the surface, is hydrophilic, and is easy to agglomerate. It has poor compatibility with polymer materials, so it is necessary to use powder modifiers to do surface treatment of magnesium hydroxide. The organic coating on its surface reduces surface energy, improves the activity of ultrafine magnesium hydroxide, and increases its dispersibility in the product, improves the strength and toughness, as well as the flame retardant performance.