The method of magnesium hydroxide modification is divided into dry method and wet method, we mainly look at the dry method modified magnesium hydroxide knowledge today. The so-called dry modification technology is to add the dry magnesium hydroxide to the appropriate amount of inert solvent, and make it and the surface modifier mixed for surface organic, mixed sufficiently after drying or other treatment, will get the modified magnesium hydroxide.
Generally commonly used modifier is coupling agent, inert solvent can be used toluene, xylene, solvent gasoline or petroleum ether. Coupling agent can effectively reduce the apparent viscosity of the composite system, improve the fluidity of the system, polypropylene and modified nano-magnesium hydroxide interface adhesion has been strengthened material tensile properties and impact strength has been increased substantially, and thus the flame retardant properties have been improved.
Can also be used silane-based surface modifier of magnesium hydroxide surface modification, to a certain extent to improve the dispersion and compatibility of magnesium hydroxide in EVA system, improve the flame retardant properties of the composite material. Silane coupling agent is a kind of low molecular silicone compound with special structure, the effect of improving the strength and heat resistance of polymer materials is more prominent, because the R in the silane coupling agent with specific functional groups, so different polymers need to choose different coupling agent to wrap magnesium hydroxide, titanate coupling agent can give the polymer material better overall performance, namely, good fluidity at processing temperature and use temperature The titanate coupling agent can give the polymer material better comprehensive performance, namely good fluidity under processing temperature and high strength and toughness under using temperature, which is more significant to improve the impact resistance, due to the strong water absorption of magnesium hydroxide, the surface humidity is high, to choose the moisture-resistant monoalkoxy pyrophosphate titanate is good.
The magnesium hydroxide and other flame retardants or flame retardant synergists through a certain method of organic combination, can significantly increase the flame retardant temperature, increase the heat absorption, reduce the amount of filling, so as to improve the flame retardant efficiency, play its comprehensive flame retardant effect. Dry modification process is low cost, but the modification effect is not as good as the wet process modification effect, wet modification has the problem of modifier loss and high cost.