Modified nano-aluminum powder, preparation method therefor, epoxy resin coating having functions of being electrically and thermally conductive and preparation method therefor

Abstract

The present application belongs to the technical field of coatings, and specifically relates to a modified nano-aluminum powder, a preparation method therefor, an epoxy resin coating having functions of being electrically and thermally conductive and a preparation method therefor. The epoxy resin coating of the present application comprises a component A and a component B, wherein the component A comprises the following components in parts by weight: 27-51 parts of a waterborne epoxy resin, 2-6 parts of modified nano-aluminum powder, 1-3 parts of active flake graphite, 10-20 parts of a solvent, 6-14 parts of a diluent, 0.1-0.3 part of a defoamer, and 0.1-0.3 part of a leveling agent, and the component B comprises the following component in parts by weight: 5-15 parts of a curing agent. Raw materials of the modified nano-aluminum powder comprise the following components in parts by weight: 2-6 parts of a nano-aluminum powder and 1-4 parts of an ionic liquid, the ionic liquid being 1-methylimidazolium tetrafluoroborate or 1-ethyl-3-methylimidazolium dicyanamide. The present application solves the problem in the prior art of poor electrical conductivity and thermal conductivity of epoxy resin coatings.

Description

Modified nano-aluminum powder, preparation method thereof, and epoxy resin coating with electrically and thermally conductive function and preparation method thereof

[0001] The present application claims priority to the Chinese patent application No. 202410739452.5, filed on June 7, 2024, and entitled "Epoxy resin coating with electrically and thermally conductive function and preparation method thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application belongs to the technical field of coatings, and particularly relates to a modified nano-aluminum powder, a preparation method thereof, and an epoxy resin coating with electrically and thermally conductive function and a preparation method thereof. BACKGROUND

[0003] In recent years, semiconductor technology has been advancing at an astonishing rate, which has driven electronic devices to develop in the direction of lighter weight, miniaturization, integration, higher power and higher frequency. With the significant increase in power density of electronic devices, the electrostatic sensitivity and heat density are continuously increasing, which seriously affects the normal operation of electronic devices. In order to solve this problem, it is particularly crucial to apply electrically and thermally conductive coatings to electronic devices. However, traditional single-component coatings have limitations in terms of electrical conductivity, and the internal current of electronic devices is difficult to dissipate quickly, resulting in local temperature rise due to charge accumulation, which seriously affects the performance and service life of electronic devices and has the risk of causing major safety accidents. In view of this, the development of new electrically and thermally conductive coatings to meet the growing demand for charge transmission and heat dissipation has become a focus of scientific research.

[0004] The commonly used electrically and thermally conductive coatings at the present stage are mainly additive type, i.e., a mixture of electrically conductive fillers, insulating film formers, additives and solvents. The main preparation method is to uniformly mix the electrically conductive fillers and the insulating film formers, and then coat them on the surface of an object, so as to use the electrically conductive fillers to conduct current and produce anti-static effect, and at the same time, to build a heat transfer channel to produce heat conduction effect. For example, nano-copper is used as an electrically conductive filler to prepare an electrically and thermally conductive coating in combination with a polyurethane system. Although the coating has good electrically and thermally conductive properties, it cannot solve the problem of oxidation and agglomeration of the surface of nano-copper. Or traditional carbon-based materials such as graphite and carbon black are used as electrically conductive fillers to prepare an electrically and thermally conductive coating in combination with a high molecular polymer, but the addition amount of the carbon-based fillers in the coating is too large, which seriously affects the performance of the coating. SUMMARY

[0005] The present application aims to provide a modified nano-aluminum powder, a preparation method thereof, and an epoxy resin coating with electrically and thermally conductive function and a preparation method thereof. The epoxy resin coating with electrically and thermally conductive function provided by the present application solves the problem of poor electrical conductivity and thermal conductivity of the epoxy resin coating in the related art.

[0006] To achieve the above object, the technical scheme provided by the present application is as follows:

[0007] The present application provides a modified nano-aluminum powder, raw materials including the following components by weight: nano-aluminum powder 2-6 parts, ionic liquid 1-4 parts;

[0008] The ionic liquid is 1-methyl imidazole tetrafluoroborate or 1-ethyl-3-methyl imidazole dicyanamide salt.

[0009] Preferably, the particle size of the nano-aluminum powder is 50-80 nm.

[0010] The present application also provides a preparation method of the modified nano-aluminum powder described in the above scheme, including the following steps:

[0011] A1, after Soxhlet extraction and reflux, the nano-aluminum powder is dried, washed to neutral pH value, and suction filtered to obtain a pretreated nano-aluminum powder;

[0012] A2, the ionic liquid is dispersed in ethanol to obtain a dispersion liquid;

[0013] A3, the pretreated nano-aluminum powder is added to the dispersion liquid, mixed, and suction filtered to obtain the modified nano-aluminum powder.

[0014] Preferably, the particle size of the nano-aluminum powder is 50-80 nm.

[0015] The present application also provides a modified nano-aluminum powder, including nano-aluminum powder and 1-methyl imidazole tetrafluoroborate or 1-ethyl-3-methyl imidazole dicyanamide salt coated on the surface of the nano-aluminum powder.

[0016] Preferably, the particle size of the nano-aluminum powder is 50-80 nm.

[0017] The present application also provides an epoxy resin paint with electrically and thermally conductive functions, including component A and component B;

[0018] The component A includes active flake graphite and modified nano-aluminum powder; the modified nano-aluminum powder is the modified nano-aluminum powder described in the above scheme or the modified nano-aluminum powder obtained by the preparation method described in the above scheme;

[0019] The component B includes a curing agent.

[0020] Preferably, the component A includes the following components by weight: water-based epoxy resin 27-51 parts, modified nano-aluminum powder 2-6 parts, active flake graphite 1-3 parts, solvent 10-20 parts, diluent 6-14 parts, defoaming agent 0.1-0.3 parts, and leveling agent 0.1-0.3 parts;

[0021] The component B comprises the following components by weight: curing agent 5-15 parts.

[0022] Preferably, the raw material of the active flake graphite comprises the following components by weight: flake graphite 1-3 parts and surfactant 0.5-2 parts.

[0023] Preferably, the fixed carbon content of the flake graphite is ≥99.9wt%.

[0024] Preferably, the particle size of the flake graphite is 0.05-1.5mm.

[0025] Preferably, the surfactant comprises sodium dodecyl sulfonate or tetradecyl trimethyl ammonium bromide.

[0026] Preferably, the preparation method of the active flake graphite comprises the following steps:

[0027] B1, adding flake graphite and surfactant into water, oscillating, suction filtering, washing, and obtaining cleaned flake graphite;

[0028] B2, adding the cleaned flake graphite into sodium hydroxide solution, stirring, suction filtering, washing until the pH value is neutral, adding nitric acid solution, stirring, suction filtering, washing until the pH value is neutral, and drying, to obtain the active flake graphite.

[0029] Preferably, the mass fraction of the sodium hydroxide solution is 2%-8%.

[0030] Preferably, the mass fraction of the nitric acid solution is 5%-15%.

[0031] Preferably, in step B1, when oscillating, water bath oscillation is adopted, the temperature of the water bath oscillation is 30-40℃, and the time is 20-40min.

[0032] Preferably, in step B2, when stirring, heating to a micro-boiling state of the system, and the stirring time is 10-30min.

[0033] Preferably, the epoxy equivalent weight of the waterborne epoxy resin is 400-800g / eq, and the solid content is 45%-55%.

[0034] Preferably, the solvent comprises one of ethanol, isopropyl alcohol and n-butanol.

[0035] Preferably, the diluent comprises one of ethanol, acetone and benzyl glycidyl ether.

[0036] Preferably, the defoaming agent is one of coconut diethanolamide, cyanuric chloride melamine and lauryl acid polyoxyethylene ether.

[0037] Preferably, the leveling agent is dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether.

[0038] Preferably, the curing agent is polyamide 651 curing agent or triethanolamine.

[0039] The application also provides a preparation method of the epoxy resin coating with the electrically and thermally conductive function as described in the above scheme, comprising the following steps:

[0040] S1, adding modified nano-aluminum and active flake graphite into ethanol, mixing, drying to obtain a premix, adding water-based epoxy resin to the premix, ball milling to obtain a mixture;

[0041] S2, mixing the mixture, component B and the remaining other components in component A to obtain an epoxy resin coating.

[0042] Preferably, in step S1, the ball milling is performed at a speed of 1000-1500 r / min for 0.5-1.5 h.

[0043] The application provides a modified nano-aluminum powder. The surface of the nano-aluminum powder is modified by ionic liquid, which can effectively avoid the agglomeration and deposition of the nano-aluminum powder and alleviate the problem of easy oxidation of the nano-aluminum powder. When the modified nano-aluminum powder is applied to an epoxy resin coating, it can promote the curing of the epoxy resin, enhance the interfacial bonding performance with the high polymer material, and thus improve the electrical conductivity and thermal conductivity of the epoxy resin coating and endow the epoxy resin coating with excellent electrically and thermally conductive performance.

[0044] The application also provides a preparation method of the modified nano-aluminum powder as described in the above scheme. The preparation method provided by the application is simple in steps and easy to operate.

[0045] The application also provides a modified nano-aluminum powder comprising nano-aluminum powder and 1-methylimidazole tetrafluoroborate or 1-ethyl-3-methylimidazole dicyanamide salt coated on the surface of the nano-aluminum powder. After the ionic liquid is blended with the nano-aluminum powder, the hydrated anion and cation are coated on the surface of the nano-aluminum powder by physical adsorption under the influence of the electronic effect of the imidazole group and dicyandiamide without forming a chemical bond with the nano-aluminum powder, and the nano-aluminum powder is coated by the ionic liquid film formed by itself. The modified nano-aluminum powder can effectively avoid the agglomeration and deposition of the nano-aluminum powder and alleviate the problem of easy oxidation of the nano-aluminum powder.

[0046] The application further provides an epoxy resin coating with electrically conductive and thermally conductive functions.

[0047] The application further provides a preparation method of the epoxy resin coating with electrically conductive and thermally conductive functions. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the application will be further described in detail below with reference to the drawings and specific embodiments. Obviously, the drawings described below are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0049] Fig. 1 is an SEM image of the modified nano-aluminum powder in Example 1;

[0050] Fig. 2 is an SEM image of the active flake graphite in Example 1;

[0051] Fig. 3 is an SEM image of the cleaned nano-aluminum powder in Comparative Example 1;

[0052] Fig. 4 is an SEM image of the cleaned flake graphite in Comparative Example 1;

[0053] Fig. 5 is an NMR spectrum of the modified nano-aluminum powder in Example 1; 1s The enlarged image of the characteristic peak;

[0054] In the figure, the red line is the modified nano-aluminum powder, and the black line is the nano-aluminum powder. DETAILED DESCRIPTION

[0055] The application provides a modified nano-aluminum powder, the raw materials including the following components by weight: 2-6 parts of nano-aluminum powder, 1-4 parts of ionic liquid.

[0056] The ionic liquid is 1-methyl imidazole tetrafluoroborate or 1-ethyl-3-methyl imidazole dicyanamide.

[0057] In the present application, the particle size of the nano-aluminum powder is preferably 50-80 nm.

[0058] The present application also provides a preparation method of the modified nano-aluminum powder described in the above scheme, comprising the following steps:

[0059] A1, after the nano-aluminum powder is extracted by Soxhlet extraction and reflux, it is dried, washed to neutral pH, and suction filtered to obtain a pretreated nano-aluminum powder;

[0060] A2, the ionic liquid is dispersed in ethanol, and mixed uniformly to obtain a dispersion liquid;

[0061] A3, the pretreated nano-aluminum powder is added to the dispersion liquid, mixed, and suction filtered to obtain the modified nano-aluminum powder.

[0062] In the present application, the particle size of the nano-aluminum powder is preferably 50-80 nm.

[0063] The present application also provides a modified nano-aluminum powder, comprising nano-aluminum powder and 1-methylimidazole tetrafluoroborate or 1-ethyl-3-methylimidazole dicyanamide salt coated on the surface of the nano-aluminum powder.

[0064] In the present application, the particle size of the nano-aluminum powder is preferably 50-80 nm.

[0065] The present application also provides an epoxy resin coating with electrically conductive and thermally conductive functions, comprising component A and component B;

[0066] The component A comprises active flake graphite and modified nano-aluminum powder; the modified nano-aluminum powder is the modified nano-aluminum powder described in the above scheme or the modified nano-aluminum powder obtained by the preparation method described in the above scheme;

[0067] The component B comprises a curing agent.

[0068] The epoxy resin coating with electrically conductive and thermally conductive functions provided by the present application comprises component A; the component A preferably comprises the following components by weight: 27-51 parts of water-based epoxy resin, 2-6 parts of modified nano-aluminum powder, 1-3 parts of active flake graphite, 10-20 parts of solvent, 6-14 parts of diluent, 0.1-0.3 parts of defoaming agent, and 0.1-0.3 parts of leveling agent.

[0069] In the present application, the raw material of the active flake graphite preferably comprises the following components by weight: 1-3 parts of flake graphite and 0.5-2 parts of surfactant.

[0070] In the present application, the fixed carbon content of the flake graphite is preferably ≥99.9wt%.

[0071] In the present application, the particle size of the flaky graphite is preferably 0.05-1.5 mm.

[0072] In the present application, the surfactant preferably includes sodium dodecyl sulfonate or tetradecyl trimethyl ammonium bromide.

[0073] In the present application, the preparation method of the active flaky graphite preferably includes the following steps:

[0074] B1, adding flaky graphite and surfactant into water, oscillating, suction filtering, washing, obtaining cleaned flaky graphite;

[0075] B2, adding the cleaned flaky graphite into sodium hydroxide solution, stirring, suction filtering, washing until the pH value is neutral, adding nitric acid solution, stirring, suction filtering, washing until the pH value is neutral, drying, obtaining the active flaky graphite.

[0076] In the present application, the mass fraction of the sodium hydroxide solution is preferably 2%-8%.

[0077] In the present application, the mass fraction of the nitric acid solution is preferably 5%-15%.

[0078] In the present application, in step B1, when oscillating, water bath oscillation is preferably adopted, the temperature of the water bath oscillation is preferably 30-40℃, and the time is preferably 20-40 min.

[0079] In the present application, in step B2, when stirring, the system is preferably heated to be slightly boiling, and the stirring time is preferably 10-30 min.

[0080] In the present application, the epoxy equivalent of the waterborne epoxy resin is preferably 400-800 g / eq, and the solid content is preferably 45%-55%.

[0081] In the present application, the solvent preferably includes one of ethanol, isopropyl alcohol and n-butanol.

[0082] In the present application, the diluent preferably includes one of ethanol, acetone and benzyl glycidyl ether.

[0083] In the present application, the defoaming agent is preferably one of coconut diethanolamide, cyanuric chloride melamine and lauryl polyoxyethylene ether.

[0084] In the present application, the leveling agent is preferably dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether.

[0085] The epoxy resin coating with electrically conductive and thermally conductive functions provided in the present application includes component B; the component B preferably includes the following components by weight: 5-15 parts of curing agent.

[0086] In the present application, the curing agent is preferably a polyamide 651 curing agent or triethanolamine.

[0087] The present application also provides a preparation method of the epoxy resin coating with the electrically and thermally conductive function as described in the above scheme, comprising the following steps:

[0088] S1, adding modified nano-aluminum and active flake graphite into ethanol, mixing, drying to obtain a premix, adding water-based epoxy resin to the premix, ball milling to obtain a mixture;

[0089] S2, mixing the mixture, component B and the remaining other components in component A to obtain an epoxy resin coating.

[0090] In the present application, in step S1, when ball milling, the rotation speed is preferably 1000-1500 r / min, and the time is preferably 0.5-1.5 h.

[0091] In order to further illustrate the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application below, but they should not be understood as limitations to the protection scope of the present application.

[0092] In the specific embodiments and comparative examples of the present application, unless otherwise specified, the epoxy equivalent weight of the water-based epoxy resin is 500±10 g / eq, and the solid content is 50±1%; the particle size of the nano-aluminum powder is 50 nm; the fixed carbon content of the flake graphite is 99.9 wt%, and the particle size is 1 mm.

[0093] Example 1

[0094] A preparation method of an epoxy resin coating with an electrically and thermally conductive function, comprising the following steps:

[0095] S1, adding 6 parts of modified nano-aluminum powder and 3 parts of active flake graphite into ethanol, mixing uniformly, vacuum drying at 120℃ to obtain a premix, adding 27 parts of water-based epoxy resin to the premix, ball milling at a rotation speed of 1300 r / min for 0.5 h to obtain a mixture;

[0096] S2, mixing the mixture, 10 parts of triethanolamine, 15 parts of ethanol, 10 parts of benzyl glycidyl ether, 0.1 parts of lauric acid polyoxyethylene ether and 0.1 parts of dipropylene glycol monomethyl ether uniformly to obtain an epoxy resin coating;

[0097] The preparation method of the modified nano-aluminum powder comprises the following steps:

[0098] A1, soxhlet extraction of 6 parts of nano-aluminum powder with acetone, reflux for 5 min, vacuum drying at 70℃, washing with deionized water until the pH value is neutral, using ether to filter 3 times, vacuum drying at 40℃, to obtain the pretreated nano-aluminum powder;

[0099] A2, 4 parts of 1-ethyl-3-methyl imidazole dicyan ammonium salt is dispersed in ethanol, mixed uniformly to obtain a dispersion liquid;

[0100] A3, adding the pretreated nano-aluminum powder into the dispersion liquid, ultrasonic mixing for 1h, vacuum filtering for 3h at 35℃, to obtain the modified nano-aluminum powder;

[0101] The preparation method of the active flake graphite comprises the following steps:

[0102] B1, adding 3 parts of flake graphite and 2 parts of sodium dodecyl sulfonate into water, water bath oscillation for 40 min at 38℃, vacuum filtering, washing with water for 3 times, washing with ether once, drying to obtain the cleaned flake graphite;

[0103] B2, adding the cleaned flake graphite into a 6% sodium hydroxide solution, heating to a micro-boiling state, stirring for 10 min, cooling to room temperature, vacuum filtering, repeatedly washing with distilled water until the pH value is neutral, adding a 6% nitric acid solution, heating to a micro-boiling state, stirring for 10 min, cooling to room temperature, vacuum filtering, repeatedly washing with distilled water until the pH value is neutral, vacuum drying at 120℃, to obtain the active flake graphite.

[0104] Example 2

[0105] The preparation method of the epoxy resin coating with the electrically and thermally conductive function comprises the following steps:

[0106] S1, adding 6 parts of modified nano-aluminum powder and 3 parts of active flake graphite into ethanol, mixing uniformly, vacuum drying at 120℃ to obtain a premix, adding 51 parts of water-based epoxy resin into the premix, ball milling at a speed of 1300r / min for 0.5h to obtain a mixture;

[0107] S2, mixing the mixture, 15 parts of triethanolamine, 20 parts of ethanol, 14 parts of benzyl glycidyl ether, 0.3 parts of lauric acid polyoxyethylene ether and 0.3 parts of dipropylene glycol monomethyl ether to obtain the epoxy resin coating;

[0108] The preparation method of the modified nano-aluminum powder and the active flake graphite is the same as that of example 1.

[0109] Example 3

[0110] A preparation method of an epoxy resin coating with electrically conductive and thermally conductive functions, comprising the following steps:

[0111] S1, 2 parts of modified nano-aluminum powder and 1 part of active flake graphite are added into ethanol, uniformly mixed, vacuum dried at 120 DEG C, to obtain a premix, 27 parts of water-based epoxy resin are added into the premix, ball milled at a speed of 1300 r / min for 0.5 h to obtain a mixture;

[0112] S2, the mixture, 5 parts of triethanolamine, 10 parts of ethanol, 6 parts of benzyl glycidyl ether, 0.1 part of lauric acid polyoxyethylene ether and 0.1 part of dipropylene glycol monomethyl ether are uniformly mixed to obtain an epoxy resin coating;

[0113] The preparation method of the modified nano-aluminum powder comprises the following steps:

[0114] A1, 2 parts of nano-aluminum powder are Soxhlet extracted with acetone, refluxed for 5 min, vacuum dried at 70 DEG C, washed with deionized water until the pH value is neutral, filtered with ether for 3 times, vacuum dried at 40 DEG C to obtain pretreated nano-aluminum powder;

[0115] A2, 1 part of 1-ethyl-3-methyl imidazole dicyan ammonium salt is dispersed in ethanol to obtain a dispersion;

[0116] A3, the pretreated nano-aluminum powder is added into the dispersion, ultrasonically mixed for 1 h, vacuum filtered for 3 h at 35 DEG C to obtain modified nano-aluminum powder;

[0117] The preparation method of the active flake graphite comprises the following steps:

[0118] B1, 1 part of flake graphite and 0.5 part of sodium dodecyl sulfonate are added into water, water-bathed and oscillated at 38 DEG C for 40 min, vacuum filtered, washed with water for 3 times, washed with ether once, and dried to obtain cleaned flake graphite;

[0119] B2, the cleaned flake graphite is added into a 6% sodium hydroxide solution, heated to a slightly boiling state, stirred for 10 min, cooled to room temperature, vacuum filtered, repeatedly washed with distilled water until the pH value is neutral, a 6% nitric acid solution is added, heated to a slightly boiling state, stirred for 10 min, cooled to room temperature, vacuum filtered, repeatedly washed with distilled water until the pH value is neutral, vacuum dried at 120 DEG C to obtain active flake graphite.

[0120] Example 4

[0121] A preparation method of an epoxy resin coating with electrically conductive and thermally conductive functions, comprising the following steps:

[0122] S1, by weight parts, 2 parts of modified nano-aluminum powder and 3 parts of active flake graphite are added into ethanol, mixed uniformly, vacuum dried at 120℃, to obtain a premix, 27 parts of water-based epoxy resin is added into the premix, ball milled at a speed of 1300r / min for 0.5h, to obtain a mixture;

[0123] S2, the mixture, 10 parts of triethanolamine, 15 parts of ethanol, 10 parts of benzyl glycidyl ether, 0.1 parts of lauric acid polyoxyethylene ether and 0.1 parts of dipropylene glycol monomethyl ether are mixed uniformly, to obtain an epoxy resin coating;

[0124] Among them, the preparation method of modified nano-aluminum powder and active flake graphite is the same as that of example 1.

[0125] Example 5

[0126] The difference between this embodiment and example 1 is that in this embodiment, the preparation method of modified nano-aluminum powder comprises the following steps:

[0127] A1, using acetone to Soxhlet extract 6 parts of nano-aluminum powder, reflux for 5min, vacuum dried at 70℃, washed with deionized water until the pH value is neutral, filtered with diethyl ether for 3 times, vacuum dried at 40℃, to obtain pretreated nano-aluminum powder;

[0128] A2, 4 parts of 1-methylimidazole tetrafluoroborate are dispersed in ethanol, mixed uniformly, to obtain a dispersion;

[0129] A3, the pretreated nano-aluminum powder is added into the dispersion, ultrasonic mixed for 1h, vacuum filtered for 3h at 35℃, to obtain modified nano-aluminum powder.

[0130] Example 6

[0131] A preparation method of an epoxy resin coating with electrically and thermally conductive functions, comprising the following steps:

[0132] S1, by weight parts, 6 parts of modified nano-aluminum powder and 3 parts of active flake graphite are added into ethanol, mixed uniformly, vacuum dried at 120℃, to obtain a premix, 27 parts of water-based epoxy resin is added into the premix, ball milled at a speed of 1300r / min for 0.5h, to obtain a mixture;

[0133] S2, the mixture, 10 parts of polyamide 651 curing agent, 15 parts of ethanol, 10 parts of benzyl glycidyl ether, 0.1 parts of lauric acid polyoxyethylene ether and 0.1 parts of dipropylene glycol monomethyl ether are mixed uniformly, to obtain an epoxy resin coating;

[0134] Among them, the preparation method of modified nano-aluminum powder and active flake graphite is the same as that of example 1.

[0135] Comparative example 1

[0136] The difference between the present comparative example and Example 1 is that in the present comparative example, the modified nano-aluminum powder is replaced by an equal amount of cleaned nano-aluminum powder, and the active flake graphite is replaced by an equal amount of washed flake graphite.

[0137] The preparation method of the cleaned nano-aluminum powder comprises the following steps: Soxhlet extraction of 6 parts of nano-aluminum powder with acetone, refluxing for 5 min, vacuum drying at 70°C, washing with deionized water until the pH value is neutral, and extracting with diethyl ether for 3 times, vacuum drying at 40°C to obtain the cleaned nano-aluminum powder.

[0138] The preparation method of the washed flake graphite comprises the following steps: adding 3 parts of flake graphite into water, water bath oscillation at 38°C for 40 min, vacuum filtration, washing with water for 3 times, washing with diethyl ether once, and air drying to obtain the washed flake graphite.

[0139] Comparative Example 2

[0140] The difference between the present comparative example and Example 1 is that in the present comparative example, the modified nano-aluminum powder and the active flake graphite are not added, and 9 parts of cleaned flake graphite are added.

[0141] The preparation method of the washed flake graphite comprises the following steps: adding 9 parts of flake graphite into water, water bath oscillation at 38°C for 40 min, vacuum filtration, washing with water for 3 times, washing with diethyl ether once, and air drying to obtain the washed flake graphite.

[0142] Comparative Example 3

[0143] The difference between the present comparative example and Example 1 is that in the present comparative example, the modified nano-aluminum powder and the active flake graphite are not added, and 9 parts of cleaned nano-aluminum powder are added.

[0144] The preparation method of the cleaned nano-aluminum powder comprises the following steps: Soxhlet extraction of 9 parts of nano-aluminum powder with acetone, refluxing for 5 min, vacuum drying at 70°C, washing with deionized water until the pH value is neutral, extracting with diethyl ether for 3 times, and vacuum drying at 40°C to obtain the cleaned nano-aluminum powder.

[0145] Experimental Example 1 Microstructure Analysis

[0146] The modified nano-aluminum powder prepared in Example 1, the active flake graphite, the cleaned nano-aluminum powder prepared in Comparative Example 1, and the washed flake graphite are characterized by SEM. The SEM image of the modified nano-aluminum powder is shown in FIG. 1, the SEM image of the active flake graphite is shown in FIG. 2, the SEM image of the cleaned nano-aluminum powder is shown in FIG. 3, and the SEM image of the washed flake graphite is shown in FIG. 4.

[0147] A comparison of Figures 1 and 3 shows that the agglomeration phenomenon of nano-aluminum powder is significantly reduced after modification. A comparison of Figures 2 and 4 shows that, compared with the cleaned flake graphite, the activated flake graphite exposes simple graphite crystal sheets, which is conducive to the bonding of active sites and can effectively reduce contact resistance and contact thermal resistance.

[0148] Experimental Example 2: X-ray photoelectron spectroscopy analysis

[0149] The modified nano-aluminum powder prepared in Example 2 was characterized by XPS. Figure 5 shows the N... 1s The magnified image of the characteristic peaks shows that the red line represents the modified nano-aluminum powder and the black line represents the nano-aluminum powder. As shown in Figure 5, the modified nano-aluminum powder has a characteristic peak at 398.4 eV, which indicates that the modified nano-aluminum powder was successfully prepared in Example 2.

[0150] Experiment Example 3: Electrical and Thermal Conductivity Tests

[0151] The epoxy resin coatings prepared in Examples 1-6 and Comparative Examples 1-3 were sprayed onto the sample stage and cured at 100°C for 2.5 h to form a 35 μm coating. The electrical conductivity and thermal conductivity of the coatings were then tested as follows:

[0152] ① Conductivity: The conductivity was tested using a surface volume resistivity tester (model HEST-200) at an ambient temperature of 23℃ and a relative humidity of 50%. The test voltage was 10VDC and the test time was 1min.

[0153] ② Thermal conductivity: The thermal conductivity was tested using an interface material thermal resistance and thermal conductivity measuring instrument (model LW-9389) at an ambient temperature of 23℃ and a relative humidity of 50%.

[0154] The test results are shown in Table 1 below.

[0155] Table 1 Test Results

[0156] A comparison between Example 1 and Comparative Example 1 shows that the addition of modified nano-aluminum powder and active flake graphite to the epoxy resin coating improves the electrical and thermal conductivity of the epoxy resin coating more effectively than the cleaned nano-aluminum powder and cleaned flake graphite. A comparison between Example 1 and Comparative Examples 2-3 shows that the epoxy resin coating prepared using modified nano-aluminum powder and active flake graphite exhibits better electrical and thermal conductivity than epoxy resin coatings with a single filler type. This is mainly attributed to the fact that the addition of modified nano-aluminum powder effectively fills the numerous gaps between the large planar flakes of the active flake graphite crystals, forming a three-dimensional structure of "active flake graphite layer - modified nano-aluminum powder - active flake graphite layer," creating a continuous "transfer bridge" structure internally, significantly enhancing the charge and heat transfer capabilities.

[0157] Comparing Example 1 and Example 5 shows that, compared with 1-methylimidazole tetrafluoroborate, the use of 1-ethyl-3-methylimidazole dicyanamide salt to modify nano-aluminum powder can further improve the conductive and thermal conductive properties of the epoxy resin coating. This is because the anion and cation of 1-ethyl-3-methylimidazole dicyanamide salt can both bond with the epoxy resin, have a potential role in promoting curing, can effectively increase the affinity of the filler and the epoxy base material, reduce the electrical and thermal resistance of the interface contact, and improve the conductive and thermal conductive properties of the coating.

[0158] Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A modified nano-aluminum powder, characterized in that, The raw material comprises the following components in parts by weight: 2-6 parts of nano-aluminum powder and 1-4 parts of ionic liquid; The ionic liquid is 1-methyl imidazole tetrafluoroborate or 1-ethyl-3-methyl imidazole dicyanamide.

2. The modified nano-aluminum powder of claim 1, wherein, The nano-aluminum powder has a particle size of 50-80 nm.

3. The method of claim 1, wherein the modified nano-aluminum powder is prepared by the steps of: The method comprises the following steps: ​ A1. After Soxhlet extraction and reflux, the nano-aluminum powder is dried, washed to neutral pH, and filtered to obtain pre-processed nano-aluminum powder; A2. The ionic liquid is dispersed in ethanol and mixed to obtain a dispersion liquid; A3. The pre-processed nano-aluminum powder is added to the dispersion liquid, mixed, and filtered to obtain the modified nano-aluminum powder.

4. The production method according to claim 3, characterized by, The nano-aluminum powder has a particle size of 50-80 nm.

5. A modified nano-aluminum powder, characterized in that, The active flake graphite comprises nano-aluminum powder and 1-methyl imidazole tetrafluoroborate or 1-ethyl-3-methyl imidazole dicyanamide coated on the surface of the nano-aluminum powder.

6. The modified nano-aluminum powder of claim 5, wherein, The nano-aluminum powder has a particle size of 50-80 nm.

7. An epoxy resin coating having an electrically and thermally conductive function, characterized by The method comprises the following steps: The component A comprises active flake graphite and modified nano-aluminum powder; the modified nano-aluminum powder is the modified nano-aluminum powder of any one of claims 1-2, the modified nano-aluminum powder obtained by the preparation method of any one of claims 3-4, or the modified nano-aluminum powder of any one of claims 5-6; The component B comprises a curing agent.

8. The epoxy resin paint having an electrically and thermally conductive function according to claim 7, characterized by, The component A comprises the following components in parts by weight: 27-51 parts of water-based epoxy resin, 2-6 parts of modified nano-aluminum powder, 1-3 parts of active flake graphite, 10-20 parts of solvent, 6-14 parts of diluent, 0.1-0.3 parts of defoaming agent, and 0.1-0.3 parts of leveling agent; The component B comprises the following components in parts by weight: 5-15 parts of curing agent.

9. The epoxy resin paint having an electrically and thermally conductive function according to claim 8, characterized by, The raw material of the active flake graphite comprises the following components in parts by weight: 1-3 parts of flake graphite and 0.5-2 parts of surfactant.

10. The epoxy resin paint having an electrically and thermally conductive function according to claim 9, characterized by, The fixed carbon content of the flake graphite is ≥99.9 wt%.

11. The epoxy resin paint having an electrically and thermally conductive function according to claim 9 or 10, characterized by, The particle size of the flake graphite is 0.05-1.5 mm.

12. The epoxy resin paint having an electrically and thermally conductive function according to claim 9, characterized by, The surfactant comprises sodium dodecyl sulfonate or tetradecyl trimethyl ammonium bromide.

13. The epoxy resin paint having an electrically and thermally conductive function according to claim 9, characterized by, The method for preparing the active flake graphite comprises the following steps: B1. Flake graphite and surfactant are added to water, oscillated, filtered, and washed to obtain cleaned flake graphite; B2. The cleaned flake graphite is added to a sodium hydroxide solution, stirred, filtered, washed to neutral pH, added to a nitric acid solution, stirred, filtered, washed to neutral pH, and dried to obtain the active flake graphite.

14. The epoxy resin paint having an electrically and thermally conductive function according to claim 13, characterized by, The mass fraction of the sodium hydroxide solution is 2-8%.

15. The epoxy resin paint having an electrically and thermally conductive function according to claim 13 or 14, characterized by, The mass fraction of the nitric acid solution is 5-15%.

16. The epoxy resin paint having an electrically and thermally conductive function according to claim 13, characterized by, In step B1, the oscillation is performed by water bath oscillation, and the water bath oscillation is performed at a temperature of 30-40°C for 20-40 min.

17. The epoxy resin paint having an electrically and thermally conductive function according to claim 13 or 16, characterized by, In step B2, the stirring is performed by heating the system to a slightly boiling state, and the stirring time is 10-30 min.

18. The epoxy resin paint having an electrically and thermally conductive function according to claim 8, characterized by, The water-based epoxy resin has an epoxy equivalent weight of 400-800 g / eq and a solid content of 45-55%.

19. The epoxy resin paint having an electrically and thermally conductive function according to claim 8 or 18, characterized by, The solvent comprises one of ethanol, isopropyl alcohol, and n-butanol.

20. The epoxy resin paint having an electrically and thermally conductive function according to claim 8 or 18, characterized by, The diluent comprises one of ethanol, acetone, and benzyl glycidyl ether.

21. The epoxy resin paint having an electrically and thermally conductive function according to claim 8 or 18, characterized by, The defoaming agent is one of coconut diethanolamide, cyanuric chloride melamine and laureate polyoxyethylene ether.

22. The epoxy resin paint having an electrically and thermally conductive function according to claim 8 or 18, characterized by, The leveling agent is dipropylene glycol monomethyl ether or dipropylene glycol monobutyl ether.

23. The epoxy resin paint having an electrically and thermally conductive function according to claim 8, characterized by, The curing agent is polyamide 651 curing agent or triethanolamine.

24. The method of producing the epoxy resin paint having electrically and thermally conductive functions according to any one of claims 7 to 23, characterized by, The method comprises the following steps: S1, adding modified nano-aluminum and active flake graphite into ethanol, mixing, drying to obtain a premix, adding water-based epoxy resin to the premix, ball milling to obtain a mixture; S2, mixing the mixture, component B and the remaining other components in component A to obtain an epoxy resin coating.

25. The method of claim 24, wherein, In step S1, when ball milling, the rotating speed is 1000-1500 r / min, and the time is 0.5-1.5 h.

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