What is the Effect of Magnesium Hydroxide on Halogen-free Flame Retardants?
There are many kinds of halogen-free flame retardants, which can be divided into inorganic and organic flame retardants. It can be divided into magnesium-aluminum, phosphorus, nitrogen, phosphorus-nitrogen, silicon, antimony, boron, molybdenum and expandable graphite. At present, halogen-free flame retardants are mainly phosphorus (phosphine) esters (including halogenated derivatives), zinc borate, aluminum hydroxide, magnesium hydroxide flame retardant, red phosphorus and antimony trioxide.
As an important product, magnesium hydroxide halogen-free flame retardant has the advantages of non-toxic, smoke-suppressing, non-volatile, heat-resistant the important products, has the advantages of non-toxicity, smoke suppression, non-volatile, good heat resistance and no corrosion waste gas. Magnesium hydroxide has been widely used in the flame retardant grade of polymer compounds because of its high decomposition reaction heat and high efficiency.
With the increasing attention to environmental protection, low-toxic, low-smoke, non-corrosive inorganic halogen-free flame retardants are popular. Magnesium hydroxide is a kind of inorganic additive flame retardant. compared with aluminum hydroxide, the thermal decomposition temperature is higher (aluminum hydroxide is about 220℃, while Mg (oh)2 is at 350~400℃), which can be used for flame retardant of engineering plastics with processing temperature higher than 250℃, and also promotes the carbon formation of polymers, and the smoke suppression is very significant.
What is the effect of magnesium hydroxide on halogen-free flame retardants?
The following conclusions were drawn from experiments:
The flame-retardant function of untreated or treated Mg (OH)2, which accounts for 65% of the total mass of composite data in the 1)PP, generally reaches UL94V-0 grade, the oxygen index is close to 30%, and the smoke suppression effect is appropriate and significant.
2) although participating Mg (oh)2 in the PP can reach a good flame retardant effect, because its high increase makes it have an appropriate degree of influence on the mechanical function of the polymer, especially the elongation decreases by more than 90%.
3) surface modified Mg (oh)2 improved the PP apparent function and mechanical function; its effect was related to the variety of coupling agents. the rare earth coupling agent was mainly able to improve the elongation of composite data and the impact strength of cantilever beam notched; while the main function of calcium stearate coupling agent was to improve the tensile strength and tortuous strength of composite data.
the effect of Mg (oh)2 4) different sources on PP function is also different, and not necessarily the higher the purity, the better the effect.
5) for the same Mg (oh)2, the advantage of dry treatment is in improving the tensile strength and tortuous strength of the data; while the advantage of wet treatment is in improving the elongation of the data and the impact strength of the cantilever beam gap; from the point of view of process, equipment demand, dry treatment has a significant advantage over wet treatment.