▎ 摘　　要

NOVELTY - Preparing high thermal conductivity insulating graphene comprises (i) obtaining uniformly dispersed graphene oxide slurry through high-energy and high-shear dispersion; (ii) forming a silane coupling agent reaction solution; (iii) pumping the graphene oxide slurry into the acid and alkali-resistant reaction kettle is equipped with stirring and jacket temperature control functions and stirring; (iv) maintaining pH and temperature; (iv) maintaining pH and temperature; (v) pumping all magnesium salts into the reactor; (vi) reacting; (vii) preparing the filter cake; (viii) reacting; (ix) cooling and reducing; (x) reacting; (xi) cooling; (xii) filtering; (xiii) converting magnesium hydroxide into magnesium oxide; (xiv) obtaining sintered aluminum-magnesium oxide; and (xv) coating the sintered aluminum-magnesium oxide alumina/magnesium-aluminum spinel/magnesium oxide using the graphene powder, pulverizing, ball milling continuously, stirring continuously, heating and drying. USE - The method is useful for preparing high thermal conductivity insulating graphene is useful in light emitting diode, phenolic resin, producing a printed circuit board, light emitting diode lamp housing and the polypropylene compound (all claimed) and for polymer materials and graphene which is useful in electronic component. ADVANTAGE - The method: provides high heat-conducting insulating graphite with high thermal conductivity with controllable performance by gradually reacts the preparation-layer agent multi-layer of magnesium-aluminum spinel ceramic as main coating graphene powder; and is economical and suitable for mass production. DETAILED DESCRIPTION - Preparing high thermal conductivity insulating graphene comprises (i) taking graphene oxide as a raw material, dispersing it in deionized water, and obtaining a uniformly dispersed graphene oxide slurry through high-energy and high-shear dispersion; (ii) dissolving soluble aluminum salt, magnesium salt and alkali in deionized water to obtain an acid-base solution, and stirring and mixing silane coupling agent, deionized water, acetic acid and ethanol to form a silane coupling agent reaction solution; (iii) pumping the graphene oxide slurry into the acid and alkali-resistant reaction kettle is equipped with stirring and jacket temperature control functions, stirring continuously, providing a pH sensor and a temperature sensor in the kettle and pumping the alkaline solution to reach a pH of 6-9, where the temperature in the reaction kettle is 20-40℃; (iv) stirring continuously, pumping aluminum salt and alkali solution continuously and maintaining pH and temperature constant by adjusting the flow rate of aluminum salt and alkali solution, so that pH is between 6 and 9 until all aluminum salt is pumped into the reaction kettle; (iv) stirring continuously, while continuing to pump aluminum salt and alkali solution and maintaining pH and temperature constant by adjusting the flow rate of aluminum salt and alkali solution, so that pH is between 6 and 9 until all aluminum salt is pumped into the reaction kettle; (v) stirring continuously while continuing to pump magnesium salt and alkaline solution, maintaining pH constant by adjusting the flow rate of magnesium salt and alkaline solution between 6 and 9 until all magnesium salts are pumped into the reactor; (vi) stirring continuously, heating up to 80-90℃, and reacting continuously for 1-3 hours to obtain the reacted slurry; (vii) filtering and dehydrating the slurry to obtain a filter cake, adding the filter cake back into the reaction kettle, adding deionized water, stirring, cleaning, filtering, dehydrating for 3 times, obtaining the filter cake after cleaning, and preparing the filter cake after cleaning into the reorganized graphene reaction slurry with deionized water; (viii) pumping the graphene reaction slurry into the autoclave until the liquid level of the autoclave is 50% of the volume of the autoclave, heating to 200-350℃ at autogenous pressure of 2-20 MPa and reacting for 10-60 minutes; (ix) cooling the autoclave to less than 90℃ and reducing the autogenous pressure to normal pressure to obtain the slurry after the pressurized reaction; and (x) pumping the graphene reaction slurry into the autoclave until the liquid level of the autoclave is 50% of the volume of the autoclave, heating to 200-350℃ at autogenous pressure of 2-20 MPa, and reacting for 10-60 minutes. INDEPENDENT CLAIMS are also included for: High thermal conductivity insulating graphene, prepared by coating multi-layer nano-ceramic film and multi-layer silane coupling agent by the graphene surface of nano thickness to carry out modification, and being provided with alumina layer near the bottom of described graphene, and the thickness of described alumina oxide layer is less than 1nm, the middle layer in each layer outside the graphene includes a magnesium-aluminum spinel layer with thickness of 1-3 nm and the outermost layer outside the graphene is a layer of magnesium oxide and magnesium hydroxide, and the thickness of the outermost layer is less than 1 nm; and Application of high thermal conductivity insulating graphene to the composite of light emitting diode and phenolic resin, when the added volume content of the high thermal conductivity insulating graphene is 25%, the thermal conductivity is higher than 3W/mK, and the resistivity is ≮108 Ω.m, when the high thermal conductivity insulating graphene is compounded with epoxy resin to produce a printed circuit board, when the added volume content of the high thermal conductivity insulating graphene is 30%, the thermal conductivity is higher than 3.5W/mK, and the resistivity is not lower than 1010Ω.m, when the high thermal conductivity insulating graphene is applied to the light emitting diode lamp housing and the polypropylene compound and when the added volume content of the high thermal conductivity insulating graphene is 30%, the thermal conductivity is not less than 3W/mK, and the resistivity is ≮ 108Ω.m.