Aluminum hydroxide (chemical) Al (OH) 3 is an aluminum hydroxide. It is a kind of alkali, which is also known as aluminic acid (H3AlO3) because it shows certain acidity, but the actual reaction with alkali is a kind of aluminate, so it is usually considered as a hydrated Dialuminate (HAlO2. H2O). Molecular formula: Al (OH) 3, Al2O3. 3H2O or H3AlO3 molecular weight: 78. The relative density is 2.42, and the moth hardness is 3. It has the characteristics of innocuity, tasteless, good dispersity, high whiteness and low iron content. It is called ATH for short. ATH is decomposed by heat and dehydration, and 1967.2J/KJ is absorbed. It can effectively inhibit the temperature rise and thermal degradation of polymers. The thermal decomposition of aluminum hydroxide releases a large amount of water vapor to dilute combustible gases and inhibit the spread of combustion. At the same time, the high temperature resistant Al2O3 produces a dense protective layer on the surface of the polymer, blocking air and preventing further diffusion of the flame. High temperature Al2O3 can promote carbonization, adsorption of solid particles and inhibition of smoke production.
Alpha aluminum hydroxide is white powder, with a relative density of 2.42 and Mohs hardness of 3. It has the characteristics of non-toxic, tasteless, good dispersibility, high whiteness and low iron content. The use of aluminum hydroxide is very wide, and its use is shown in the following aspects: artificial marble fillers, flame retardant fillers of vinyl chloride paste, epoxy resin, unsaturated polyester resin and other plastic products; catalyst and catalyst carrier; Toothpaste filler; paper filler and coating agent; high purity glass special filler for integrated circuit and optics, high purity aluminum salt filler and fiber post-processing AIDS.
Aluminum hydroxide (a-Al2O3. 3H2O), called ATH, is widely used as a halogen free flame retardant for synthetic materials after super refinement. It can be used in combination with various organic flame retardants to produce synergistic effect and improve the flame retardancy and physical and mechanical strength of the material. ATH is decomposed by heat and dehydration, and its heat absorption reaches 1967.2J/kg. It can effectively inhibit the temperature rise and thermal degradation of polymers. ATH decomposes a large amount of water vapor to dilute flammable gases and inhibit combustion. The tightly packed ATH double layer crystal structure can capture hydroxyl radicals initiating polymer combustion and break off the chain reaction. After ATH dehydration, a high temperature and compact Al2O3 protective film is formed on the polymer surface, and the air is isolated to prevent flame propagation. High temperature and compact Al2O3 protective film can also promote polymer carbonization, adsorb solid particles and suppress smoke generation.
Alpha hydroxide is one of the largest inorganic flame retardants in the world at present. It has three functions of flame retardancy, smoke elimination and filling. It has no two pollution during combustion. It does not produce toxic and corrosive gases, and absorbs and releases steam. It has the property of flame retardant and self extinguishing. It not only has good dispersion in polyolefin, but also is easy to produce synergistic effect with other additives. In addition, because of the existence of crystalline water, it can also make polymer products endow antistatic function and improve the strength and toughness of polymer.
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