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CN-122011806-A - Preparation method of flaky magnesium hydroxide flame retardant

CN122011806ACN 122011806 ACN122011806 ACN 122011806ACN-122011806-A

Abstract

The invention discloses a preparation method of a sheet magnesium hydroxide flame retardant, which belongs to the technical field of inorganic material preparation, and comprises 2 steps of precipitation synthesis and epoxy coating, wherein the particle size distribution of the sheet magnesium hydroxide flame retardant is 0.022-0.034 mu m, D 50 is 0.591-0.608 mu m, D 90 is 1.398-1.749 mu m, the sheet magnesium hydroxide flame retardant is added into EVA in an additive amount of 40wt%, the limiting oxygen index of the EVA is raised to 31.1-32.0%, and the vertical combustion grade of UL94 can reach V-1.

Inventors

  • LIU CHUNXIAO
  • CUI CUNLI
  • TONG YANXIA

Assignees

  • 山东艾科高分子材料有限公司

Dates

Publication Date
20260512
Application Date
20260414

Claims (5)

  1. 1. A preparation method of a flaky magnesium hydroxide flame retardant is characterized in that: The preparation method of the flaky magnesium hydroxide flame retardant comprises 2 steps of synthesis by a precipitation method and epoxy coating; The method comprises the steps of synthesizing by a precipitation method, putting magnesium salt, a pH buffering agent, a morphology control agent, a dispersing agent and deionized water into a reaction kettle, stirring and dissolving completely, heating to a reaction temperature, dropwise adding ammonia water under constant-temperature stirring, controlling the dropwise adding speed to ensure that the pH value of a reaction system is stabilized at 9.8-10.3, continuously stirring until the reaction is complete after the dropwise adding is finished, discharging, and filtering, washing and drying to obtain a sheet magnesium hydroxide flame retardant primary product; The pH buffer is a mixture of 2,4, 6-tris (aminocaproate) -1,3, 5-triazine and triethanolamine borate; The morphology control agent is one or a mixture of two of succinic acid dihydrazide and 2, 3-dihydroxysuccinic acid dihydrazide according to any mass ratio; the dispersing agent is one or a mixture of two of sodium polymethacrylate and ammonium polymethacrylate in any mass ratio; And (3) epoxy coating, namely placing E20 epoxy resin, methylated hexamethylol melamine resin and ethylene glycol monobutyl ether into a dispersion reaction kettle, stirring and dissolving completely, adding a sheet magnesium hydroxide flame retardant primary product, heating to a reaction temperature after strong dispersion is uniform, adding diethylenetriamine under low-speed dispersion, cooling to room temperature after the curing reaction is complete, discharging, filtering, washing and drying to obtain the sheet magnesium hydroxide flame retardant.
  2. 2. The method for preparing the flaky magnesium hydroxide flame retardant according to claim 1, wherein: the magnesium salt is one or a mixture of more than two of magnesium nitrate, magnesium chloride and magnesium sulfate in any mass ratio.
  3. 3. The method for preparing the flaky magnesium hydroxide flame retardant according to claim 1, wherein: the mass ratio of the 2,4, 6-tri (amino caproyl) -1,3, 5-triazine to the triethanolamine borate is 13-37:45.
  4. 4. The method for preparing the flaky magnesium hydroxide flame retardant according to claim 1, wherein: The mass concentration of the ammonia water is 6-15wt%; The magnesium salt, the pH buffering agent, the morphology control agent, the dispersing agent, the deionized water the mass ratio of the ammonia water is 35-115:3-11:2-10:1-6:290-880:110-540.
  5. 5. The method for preparing the flaky magnesium hydroxide flame retardant according to claim 1, wherein: The mass ratio of the E20 epoxy resin to the methylated hexamethylol melamine resin to the ethylene glycol monobutyl ether to the flaky magnesium hydroxide flame retardant primary product to the diethylenetriamine is 20-80:1-10:500-1200:150-330:2-11.

Description

Preparation method of flaky magnesium hydroxide flame retardant Technical Field The invention relates to a preparation method of a flaky magnesium hydroxide flame retardant, belonging to the technical field of inorganic material preparation. Background Magnesium hydroxide is a white odorless solid, is hardly dissolved in water, and is used as a novel inorganic environment-friendly functional material, and the magnesium hydroxide has application potential in the aspects of preparing flame retardants, water treatment agents, medicine antacids, historical relics protection and the like. When the magnesium hydroxide is used as a flame retardant, the particle size of the magnesium hydroxide is used as the most important influencing factor, so that the mechanical property and the flame retardant property of the high polymer material are influenced. Compared with common micron-sized magnesium hydroxide, the nano magnesium hydroxide has the remarkable advantages that the nano size and the high specific surface area of the nano magnesium hydroxide can increase the contact area between the nano magnesium hydroxide and a flame retardant material, the flame retardant effect is improved, especially the nano-sized flaky magnesium hydroxide can achieve the same or even better flame retardant effect under the condition of lower addition amount due to the higher specific surface area, so that the use amount of the material is reduced, the production cost is reduced, the consumption of resources is reduced, better dispersibility of the flaky magnesium hydroxide is easy to obtain, smaller mechanical property loss is generated, and the damage of the magnesium hydroxide flame retardant to the mechanical property of a matrix material is reduced relatively. In general, compared with micron-sized magnesium hydroxide, the nanoscale flaky magnesium hydroxide has smaller particle size, better morphology and less filling quantity, has the volume effect, the surface effect, the quantum size effect and the like of a nano material, and has remarkable effect in the aspect of strengthening the performance of a high polymer material. Therefore, the nano flaky magnesium hydroxide flame retardant has wide application prospect, and the preparation and modification technology of the nano flaky magnesium hydroxide flame retardant is paid attention to and is widely studied. Chinese patent CN116284996A discloses a preparation method of a hexagonal flaky magnesium hydroxide flame retardant, which comprises the following steps of respectively and simultaneously adding a precipitant and a magnesium chloride solution into a vertical ultrasonic tubular reactor for precipitation reaction to obtain magnesium hydroxide precipitate and a hydrothermal modifier for hydrothermal reaction in a microwave stirring kettle type reactor to obtain the magnesium hydroxide flame retardant, wherein the ultrasonic tubular reactor is a lower inlet and upper outlet type magnesium chloride solution (magnesium ions), the molar ratio of the precipitant (hydroxyl ions) to the magnesium chloride solution is 2:1, the linear speed of the tail end of a stirring blade in the microwave stirring kettle type reactor is 0.5-1.5 m/s, and the hydrothermal reaction time is 30-120 min. The hexagonal flaky magnesium hydroxide flame retardant obtained by the patent has good particle size and morphology, but can be obtained by a hydrothermal process, the hydrothermal synthesis equipment is complex and expensive, the conditions are relatively harsh, and the current industrialized implementation is difficult. Chinese patent CN120057960A discloses a synthesis method and flame-retardant application of hexagonal flaky magnesium hydroxide, which comprises the steps of dissolving mineralizer, crystal form control agent and magnesium chloride in water according to a proportion, putting a certain amount of mixed solution into a high-pressure reaction kettle for hydrothermal reaction, taking out cooled solution from the high-pressure reaction kettle after the reaction is finished, filtering and separating white products, and grinding a dried sample to obtain pure magnesium hydroxide powder. The patent still utilizes hydrothermal reaction to obtain hexagonal flaky magnesium hydroxide with good particle size and morphology, short plates exist in industrialized implementation, and according to the flame retardant property test data disclosed in the patent, the addition amount of the hexagonal flaky magnesium hydroxide in EVA reaches 50wt%, the oxygen index can only reach about 30, and the flame retardant grade can only reach V-2 grade of UL-94. The preparation method of the nanoscale flaky magnesium hydroxide still has the outstanding problems of harsh synthesis method conditions, difficult industrialization, poor flame retardant property and the like, so the development of the preparation method of the nanoscale flaky magnesium hydroxide high-efficiency flame retardant which is easy to industrialize and