Modification method: Under the condition of constant temperature 80℃, the modifier (2%) solution dispersed in anhydrous ethanol and magnesium hydroxide are mixed into slurry in the ratio of 1:1.5 and modified for 2h. After modification, filtering, drying at 135℃ and grinding to get modified magnesium hydroxide powder.
Modifier: titanate coupling agent CS-201, CS-311, phosphorus-containing organic flame retardant cresol diphenyl phosphate, dimethyl phosphite, dosage 2%, modified 2h.
Testing and characterization: infrared spectroscopy, thermogravimetry, electron microscopy and particle size, and the fabricated modified magnesium hydroxide was added into EVA as flame retardant to test the material properties.
magnesium hydroxide modification method
At present, it is common to make the surface chemical modification is the most common modification method of magnesium hydroxide, including thousand method modification, wet method modification and online modification. Dry modification process is simple, but the modification effect is not ideal; wet modification effect is better, but there is a modifier with the loss of water, the problem of rising costs; online modification in the powder preparation process in addition to effectively control its agglomeration, but also can shorten the process, saving production costs. This paper is a wet modification of magnesium hydroxide with silane coupling agent vinyltriethoxysilane (A-151) as a modifier.
Surface modification methods, surface chemical modification, dry modification, wet modification, in-line modification
Commonly used surface modifiers mainly include: surface modifier, organophosphate coupling agent, polymeric coating agent.
Modification effect: titanate coupling agent CS-201, CS-311 and organic flame retardant cresol diphenyl phosphate, dimethyl phosphite modified MH can all play a role in reducing particle agglomeration and improving particle size dispersion, the best effect is titanate coupling agent CS-311. organic flame retardant cresol diphenyl phosphate modified MH can improve the heat resistance and mass retention of magnesium hydroxide at high temperature. Titanate coupling agent CS-311 modified magnesium hydroxide is the best compatibility with EVA resin, greatly improve the elongation at break; cresol diphenyl phosphate modified modified magnesium hydroxide flame retardant effect is the best.