Thermal interface material based on vinyl imidazole ionic liquid as well as preparation method and application of thermal interface material

Abstract

The invention provides a thermal interface material based on vinyl imidazole ionic liquid as well as a preparation method and application of the thermal interface material. The thermal interface material is prepared from the following raw materials: the vinyl imidazole ionic liquid, a heat-conducting filler subjected to surface treatment by a silane coupling agent, an initiator and a cross-linking agent. The thermal interface material is based on the vinyl imidazole ionic liquid and the heat-conducting filler, the limitation of a traditional thermal interface material base body is broken through, dispensing can be achieved, no solvent is needed in the preparation process, the adverse effect of solvent residues on the performance of a chip when the thermal interface material is applied to the chip subsequently can be avoided, and the thermal interface material has ideal interface bonding strength; the heat conduction effect is remarkable and stable, the heat stability is good, the material can be well attached to an interface, the problems of stress concentration, cracks and the like are not prone to occurring, and the material can be widely applied to the heat conduction and heat dissipation fields of aerospace, advanced energy, electronic information, military industry and the like.

Description

Technical Field

[0001] This invention belongs to the field of thermal interface materials technology, specifically relating to a thermal interface material based on vinylimidazole ionic liquid, its preparation method, and its application. Background Technology

[0002] The rapid development of the integrated circuit industry is driving the rapid progress of the electronics and information industry. As electronic devices become smaller and more integrated, the power density of chips is increasing rapidly, placing higher demands on the thermal conductivity, mechanical compliance, and long-term stability of thermal interface materials. Traditional organic polymer-based thermal interface materials, such as silicone and epoxy resin-based thermal interface materials, generally suffer from problems such as limited thermal conductivity, low interfacial adhesion, poor interfacial contact, elastic modulus mismatch, and poor aging stability.

[0003] Polyionic liquids possess unique physicochemical properties, such as low vapor pressure, high thermal stability, strong interfacial adhesion, good electrical conductivity, and tunable physicochemical properties, and have attracted widespread attention in the field of thermal interface materials in recent years. Adding thermally conductive fillers to polyionic liquids to prepare thermal interface materials is an effective method. Thermally conductive gels fill the tiny gaps between electronic components and heat sinks, eliminating air, a poor conductor of heat, thereby forming continuous thermally conductive channels and significantly improving the efficiency of heat transfer from the heat source to the heat sink. The matrix material for thermally conductive gels is generally silicone oil or organosilicon resin; this invention uses polyionic liquids to replace traditional organosilicon systems to prepare novel thermally conductive gels.

[0004] CN118667278A discloses a thermal interface material comprising the following volume percentages of raw materials: 1%-100% polyionic liquid and 0%-99% thermally conductive filler; wherein the polyionic liquid is a polyvinylimidazole ionic liquid. In this invention, the thermal interface material is obtained directly using polyvinylimidazole ionic liquid as a raw material. However, the preparation process requires the use of organic solvents, resulting in solvent residues in the final product, which can adversely affect chip performance when applied to chips.

[0005] Therefore, it is hoped that new thermal interface materials can be developed in this field to solve the above-mentioned technical problems and avoid affecting chip performance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a thermal interface material based on vinylimidazole ionic liquid, its preparation method, and its application. The thermal interface material of the present invention is based on vinylimidazole ionic liquid and thermally conductive filler, breaking through the limitations of traditional thermal interface material matrices. Furthermore, it allows for dispensing and eliminates the need for solvents during preparation, thus avoiding the adverse effects of solvent residues on chip performance when subsequently applied to chips.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] On one hand, the present invention provides a thermal interface material based on vinylimidazole ionic liquid, wherein the raw materials for preparing the thermal interface material include the following components: vinylimidazole ionic liquid, thermally conductive filler surface-treated with silane coupling agent, initiator and crosslinking agent.

[0009] The thermal interface material provided by this invention possesses ideal interfacial bonding strength and good adhesion performance, excellent elongation at break, significant and stable thermal conductivity, and good thermal stability. It can operate normally over a wide temperature range and can be widely used in thermal management and heat dissipation fields such as aerospace, advanced energy, electronic information, and military industries. Since no solvent is used in the preparation of the thermal interface material of this invention, it does not contain residual solvents introduced by the preparation method, thus avoiding any adverse effects of solvent residues on chip performance when subsequently applied to chips.

[0010] Preferably, the cation of the vinylimidazole ionic liquid is selected from any one or a combination of at least two of the following cations: (1-acetonitrile-3-vinylimidazole), (1-ethyl-3-vinylimidazole), (1-butyl-3-vinylimidazole), (1-octyl-3-vinylimidazole), (1-dodecyl-3-vinylimidazole), (1-(2-(ethoxy)ethyl)-3-vinylimidazole), (1-(2-(2-ethoxyethoxy)ethyl)-3-vinylimidazole), (1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazole).

[0011] Preferably, the anion of the vinylimidazolium ionic liquid is selected from any one of the following anions: bis(trifluoromethanesulfonyl)imide anion, trifluoromethanesulfonic acid anion, tetrafluoroborate anion, hexafluorophosphate anion, chloride ion, or bromide ion.

[0012] In this invention, the vinylimidazole ionic liquid has the following structure:

[0013]

[0014] in Selected from The wavy line represents the connection site of the functional group;

[0015] Selected from Cl - or Br - .

[0016] Preferably, the vinylimidazolium ionic liquid is 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-vinyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-vinylimidazolium tetrafluoroborate, 1-dodecyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, or 1-(2-(ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0017] Preferably, the silane coupling agent is selected from any one or a combination of at least two of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, vinyltriethoxysilane, vinyltritert-butylperoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, bis-[3-(triethoxysilyl)propyl]tetrasulfide, γ-ureapropyltriethoxysilane, γ-isocyanate-propyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane quaternary ammonium salt, and tridecafluorooctyltrimethoxysilane.

[0018] Preferably, the thermally conductive filler is selected from one or a combination of at least two of the following: metallic thermally conductive fillers, ceramic thermally conductive fillers, or carbon thermally conductive fillers.

[0019] Preferably, the metallic thermally conductive filler is selected from any one or a combination of at least two of liquid metal, gold, silver, copper or aluminum.

[0020] Preferably, the ceramic thermally conductive filler is selected from any one or a combination of at least two of aluminum nitride, aluminum oxide, zinc oxide, or boron nitride.

[0021] Preferably, the carbon-based thermally conductive filler is selected from any one or a combination of at least two of silicon carbide, graphene, or carbon nanotubes.

[0022] Preferably, the volume ratio between the vinylimidazolium ionic liquid and the thermally conductive filler is 1:(1-99), such as 1:1, 1:3, 1:5, 1:8, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, 1:80, 1:85, 1:90, 1:95, or 1:99, etc., preferably 1:(2-10).

[0023] In this invention, the raw materials for preparing the thermal interface material include an initiator.

[0024] Preferably, the initiator is any one or a combination of at least two of the following: azobisisobutyronitrile, methyl azobisisobutyrate, azobis(2-methylpropionitrile), diisopropyl azodicarbonate, azodicarbonamide, dicumyl peroxide, tert-butyl peroxide, hydrogen peroxide, lauric acid peroxide, benzoyl peroxide, dibenzoyl peroxide, tert-butyl peroxide (2-ethylhexanoate), ammonium persulfate / sodium bisulfite, 2-hydroxy-2-methyl-1-phenylpropanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, and ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

[0025] Preferably, the volume ratio of the vinylimidazole ionic liquid to the initiator is 1000:(1-100), for example, 1000:0.1, 1000:0.5, 1000:0.8, 1000:1, 1000:3, 1000:5, 1000:10, 1000:20, 1000:30, 1000:35, 1000:40, 1000:50, 1000:55, 1000:60, 1000:65, 1000:70, 1000:80, 1000:85, 1000:90, 1000:95, 1000:100, etc., preferably 1000:(1-10).

[0026] In this invention, the raw materials for preparing the thermal interface material include a crosslinking agent.

[0027] Preferably, the crosslinking agent is any one or a combination of at least two of N,N'-methylenebisacrylamide, maleimide, hexamethylene diisocyanate, triisocyanate, glycidyl acrylate, polyethylene glycol diacrylate, neopentyl glycerol triacrylate, pentaerythritol tetraacrylate, divinylbenzene, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, terephthalic acid diacrylate, bisphenol A diacrylate, diethylenetriamine, or ethylene glycol dimethacrylate, and more preferably N,N'-methylenebisacrylamide or polyethylene glycol diacrylate.

[0028] Preferably, the volume ratio of the vinylimidazolium ionic liquid to the crosslinking agent is 1000:(1-100), for example, 1000:0.1, 1000:0.5, 1000:0.8, 1000:1, 1000:3, 1000:5, 1000:10, 1000:20, 1000:30, 1000:35, 1000:40, 1000:50, 1000:55, 1000:60, 1000:65, 1000:70, 1000:80, 1000:85, 1000:90, 1000:95, 1000:100, etc., preferably 1000:(1-10).

[0029] Preferably, the raw materials for preparing the thermal interface material also include additives.

[0030] Preferably, the additives include one or a combination of at least two of the following: dispersants, wetting agents, flow aids, coupling agents, stabilizers, anti-aging agents, thixotropic agents, thickeners, toughening agents, or other additives.

[0031] Preferably, the dispersant comprises any one or a combination of at least two of the following: alkylsilane coupling agents, aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, polyether-modified polysiloxane, polycarboxylate dispersants, quaternary ammonium salt surfactants, or sulfosuccinate surfactants.

[0032] Preferably, the wetting agent or flow aid includes any one or a combination of at least two of the following: polydimethylsiloxane, modified polyether polyol, polyethylene glycol and its ether derivatives, phosphate ester wetting agents, silicone oil modified leveling agents, and nonionic surfactants.

[0033] Preferably, the coupling agent comprises any one or a combination of at least two of γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, isocyanate-functionalized silane, 3-mercaptopropyltrimethoxysilane, octadecyltrimethoxysilane, or allyltrimethoxysilane.

[0034] Preferably, the stabilizer or anti-aging agent includes hindered phenolic antioxidants, phosphite antioxidants, ultraviolet absorbers, and peroxide decomposition inhibitors;

[0035] Preferably, the thixotropic agent or thickener includes any one or a combination of at least two of bentonite, fumed silica, polyamide wax, and polyurethane rheology modifier.

[0036] Preferably, the toughening agent includes any one or a combination of at least two of the following: carboxylated nitrile rubber, polyacrylate rubber, maleic anhydride-grafted ethylene propylene rubber, block copolymer thermoplastic elastomer, hydroxyl-terminated polyether polyol, polycarbonate polyol, and acrylate core-shell toughening agent.

[0037] Preferably, the other additives include any one or a combination of at least two of the following: aluminum hydroxide, antimony trioxide, phosphate ester flame retardants, color modifiers, or polysiloxane release agents.

[0038] On the other hand, the present invention provides a method for preparing a thermal interface material based on vinylimidazole ionic liquid as described above, the preparation method comprising the following steps:

[0039] (1) Mix vinylimidazolium ionic liquid with crosslinking agent and initiator to obtain ionic liquid mixture;

[0040] (2) Add the thermally conductive filler that has been surface-treated with silane coupling agent to the ionic liquid mixture obtained in step (1), mix evenly, add optional additives, and obtain a mixture;

[0041] (3) The mixture obtained in step (2) is cured to obtain the thermal interface material based on vinylimidazolium ionic liquid.

[0042] In this invention, vinylimidazole ionic liquid is used as a raw material to prepare thermal interface materials. No solvent is needed in the entire preparation process, and no solvent removal is required after product preparation. Moreover, the performance of the product when applied to chips will not be affected by residual solvent.

[0043] Preferably, the mixing time in step (1) is 1-3 hours, for example, 1 hour, 1.3 hours, 1.5 hours, 1.8 hours, 2 hours, 2.3 hours, 2.5 hours, 2.8 hours or 3 hours.

[0044] Preferably, the mixing in step (2) is carried out by mechanical stirring or ultrasonic dispersion.

[0045] Preferably, the mixing in step (2) is carried out under stirring, the stirring time is 1-20 min, for example 1 min, 3 min, 5 min, 8 min, 10 min, 12 min, 15 min, 18 min or 20 min, and the stirring rate is 200-3000 r / min, for example 200 r / min, 220 r / min, 250 r / min, 280 r / min or 300 r / min.

[0046] Preferably, the curing temperature in step (3) is 60-100℃, for example 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, and the curing time is 2-5h, for example 2h, 3h, 4h or 5h.

[0047] In this invention, after curing in step (3), the cured sample is demolded and can be further polished, cut, patched or pressed, or directly cured at the interface bonding area.

[0048] On the other hand, the present invention provides a thermally conductive and heat-dissipating material, which includes the thermal interface material as described above.

[0049] On the other hand, the present invention provides the application of the thermal interface material or the thermally conductive and heat dissipation material as described above in a chip.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The thermal interface material provided by this invention has ideal interfacial bonding strength, significant and stable thermal conductivity, and good thermal stability, making it suitable for thermal management of high-power devices. The obtained thermal interface material forms a three-dimensional network structure, which improves its adhesion and mechanical stability. In practical applications, it can fit well with the interface and is not prone to stress concentration and cracking, ensuring effective heat transfer over a long period of time. The ionic liquid component endows the material with good thermal stability. The preparation process is simple and easy to industrialize, and it can be widely used in thermal conduction and heat dissipation fields such as aerospace, advanced energy, electronic information, and military industries.

[0052] The raw materials for preparing the thermal interface material in this invention do not contain solvents, so there is no need to remove solvents after product preparation, and the product will not be affected by residual solvents when applied to chips. Attached Figure Description

[0053] Figure 1 The diagram shows the structure of the prepared thermal interface material, where 1 is the thermal interface material, 11 is the polyionic liquid, 12 is the high thermal conductivity filler, and 13 is the crosslinking agent.

[0054] Figure 2 Flowchart of the preparation method of vinylimidazolium polyionic liquid thermal interface material;

[0055] Figure 3 The 1H NMR spectrum of 1-vinyl-3-1-(2-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1;

[0056] Figure 4 Here are SEM images of the thermal interface material obtained in Example 1;

[0057] Figure 5 A photograph of the torsional bending material obtained in Example 1;

[0058] Figure 6 The results show the interfacial adhesion strength between the thermal interface material and different substrates obtained in Example 1.

[0059] Figure 7 The image shows the tensile curve of the thermal interface material obtained in Example 1.

[0060] Figure 8 This is a coverage map of Example 1. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] In the following examples, the thermal conductivity was tested according to the standard test method of ASTM E 1461 for determining thermal diffusivity by flash method. The tensile properties were tested according to the national standard GB / T 1040.3-2006. The interfacial bond strength was tested according to the national standard GB / T 7124-2008. The interfacial thermal resistance was tested by FDTR method. The samples were subjected to thermal shock test, with the temperature alternating every 15 minutes from -55℃ to 125℃. The coverage was observed after 100 temperature shocks.

[0063] Example 1

[0064] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, the specific steps include:

[0065] (1) Weigh out 30 parts by volume of 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.15 parts of polyethylene glycol diacrylate (Maclean, MKL-P816109) (0.5% of ionic liquid), 0.15 parts of tert-butyl peroxide (2-ethylhexanoic acid), and 70 parts of alumina modified with silane coupling agent (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0066] (2) The 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, polyethylene glycol diacrylate and tert-butyl peroxide (2-ethylhexanoic acid) from step (1) are mixed in a glass bottle and stirred on a long shaft mixer at a stirring speed of 100 rpm to obtain an ionic liquid mixture.

[0067] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 5 min to obtain the mixture.

[0068] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 85°C, and the curing time to 4 hours. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0069] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 1.7 W / (m·K), and its interfacial thermal resistance was 1.95 mm. 2• K / W, tensile strength is 0.65 MPa, elongation at break is 43%, bond strength with glass sheet is 1.01 MPa, and coverage after aging is 90%.

[0070] The 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1 was prepared by the following method: 0.45 mol of thionyl chloride solvent and 90 mL of chloroform were mixed and slowly added over 60 minutes to a mixed solution of triethylene glycol monomethyl ether (0.45 mol), pyridine (0.3 mol), and chloroform (200 mL). The mixture was stirred and refluxed in an oil bath at 100 °C for 4 hours, resulting in a yellow, turbid liquid mixture. This mixture was washed four times with pure water, dried over MgSO4, and distilled under reduced pressure at 60 °C to remove chloroform. The crude product was purified under reduced pressure to give 2-[2-(2-methoxyethoxy)ethoxy]ethyl chloride, which was an orange, transparent liquid. Next, equimolar amounts of 2-[2-(2-methoxyethoxy)ethoxy]ethyl chloride and N-vinylimidazolium were stirred and reacted at 100 °C for 72 h. After the reaction was completed, the mixture was washed with diethyl ether to remove unreacted impurities. After drying, it was subjected to ion exchange with an equimolar amount of lithium bis(trifluoromethanesulfonate)imide in aqueous solution. After the exchange was completed, the mixture was separated and dried to obtain 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonate)imide salt.

[0071] Figure 3 The NMR characterization results are for 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1, with deuterated chloroform as the solvent.

[0072] Figure 4 The image shows the SEM image of the thermal interface material obtained in Example 1. It can be seen that the filler is well dispersed and there is no obvious agglomeration, indicating that the filler is uniformly dispersed.

[0073] Figure 5 The image shows a torsion and bending photograph of the thermal interface material obtained in Example 1; it can be seen that the prepared thermal interface material has good flexibility.

[0074] Figure 6 The results of the interfacial bonding strength between the thermal interface material obtained in Example 1 and different substrates show that the bonding strength between the thermal interface material and glass, silicon, aluminum, copper, etc. is above 0.8 MPa, indicating good interfacial bonding strength.

[0075] Figure 7 The image shows the tensile curve of the thermal interface material obtained in Example 1; it can be seen that the obtained thermal interface material has low modulus and good elongation at break.

[0076] Figure 8 The figure shows the coverage of Example 1. The figure is an X-ray image of the bonding effect between a 1cm×1cm silicon wafer and the sample. The effect in the figure shows that the coverage is good.

[0077] Example 2

[0078] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, its preparation method includes the following steps:

[0079] (1) Weigh out 40 parts by volume of 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.15 parts of tert-butyl peroxide (2-ethylhexanoic acid), 0.2 parts of polyethylene glycol diacrylate (0.5% of ionic liquid), and 60 parts of alumina modified with silane coupling agent (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0080] (2) The 1-vinyl-3-1-(2-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, polyethylene glycol diacrylate and azobisisobutyronitrile from step (1) are mixed in a glass bottle and stirred on a long shaft mixer for 1 hour to obtain an ionic liquid mixture.

[0081] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 5 min to obtain the mixture.

[0082] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 85°C, and the curing time to 4 hours. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0083] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 1.3 W / (m·K), and its interfacial thermal resistance was 2.15 mm. 2 • K / W, tensile strength is 0.33 MPa, elongation at break is 112%, bond strength with glass sheet is 1.58 MPa, and coverage after aging is 89%.

[0084] Example 3

[0085] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, its preparation method includes the following steps:

[0086] (1) Weigh out 50 parts by volume of 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.15 parts of tert-butyl peroxide (2-ethylhexanoic acid), 0.25 parts of polyethylene glycol diacrylate (0.5% of ionic liquid), and 50 parts of alumina modified with silane coupling agent (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0087] (2) The 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, polyethylene glycol diacrylate and tert-butyl peroxide (2-ethylhexanoic acid) from step (1) are mixed in a glass bottle and stirred on a long shaft mixer for 1 hour to obtain an ionic liquid mixture.

[0088] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 5 min to obtain the mixture.

[0089] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 85°C, and the curing time to 4 hours. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0090] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 0.8 W / (m·K), and its interfacial thermal resistance was 2.33 mm. 2 • K / W, tensile strength is 0.18 MPa, elongation at break is 192%, bond strength with glass sheet is 1.85 MPa, and coverage after aging is 91%.

[0091] Example 4

[0092] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, its preparation method includes the following steps:

[0093] (1) Weigh out 30 parts of 1-vinyl-3-methylimidazolium tetrafluoroborate (CAS No.: 143314-16-3), 0.15 parts of tert-butyl peroxide (2-ethylhexanoate), 0.15 parts of polyethylene glycol diacrylate (0.5% of ionic liquid), and 70 parts of alumina with a particle size D50 of 6.1 μm by volume.

[0094] (2) Mix 1-vinyl-3-methylimidazolium tetrafluoroborate, 0.15 parts of tert-butyl peroxide (2-ethylhexanoate) and polyethylene glycol diacrylate in a glass bottle and mix them by rotating and stirring on a long shaft mixer for 1 hour to obtain an ionic liquid mixture.

[0095] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 5 min to obtain the mixture.

[0096] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 85°C, and the curing time to 4 hours. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0097] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 1.3 W / (m·K), and its interfacial thermal resistance was 1.98 mm. 2 • K / W, tensile strength is 0.35 MPa, elongation at break is 105%, bond strength with glass sheet is 1.40 MPa, and coverage after aging is 90%.

[0098] Example 5

[0099] The difference from Example 1 is the addition of 0.5 parts of vinyltriethoxysilane; all other raw materials and preparation steps are the same. The mixing effect is more uniform and better than that of Example 1. The thermal interface material prepared in this example was tested for thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity is 1.7 W / (m·K), and its interfacial thermal resistance is 1.90 mm. 2 The tensile strength (K / W) is 0.62 MPa, the elongation at break is 45%, the bond strength with the glass sheet is 1.02 MPa, and the coverage after aging is 91%. This indicates that the introduction of additives such as silane coupling agents has a certain promoting effect on the bonding of the organic and inorganic interfaces.

[0100] Example 6

[0101] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2As shown, the specific steps include:

[0102] (1) Weigh out 20 parts by volume of 1-butyl-3-vinylimidazolium tetrafluoroborate (CAS No.: 1033461-44-7), 0.1 parts of N,N'-methylenebisacrylamide, 0.15 parts of azobisisobutyronitrile, and 80 parts of alumina modified with silane coupling agent (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0103] (2) The 1-butyl-3-vinylimidazolium tetrafluoroborate, azobisisobutyronitrile and N,N'-methylenebisacrylamide from step (1) are mixed in a glass bottle and stirred on a long shaft mixer at a stirring speed of 2000 rpm for 2 hours to obtain an ionic liquid mixture.

[0104] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 3000 rpm for 10 min to obtain the mixture.

[0105] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 100℃, and the curing time to 2h. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0106] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 2.5 W / (m·K), and its interfacial thermal resistance was 2.85 mm. 2 • K / W, tensile strength is 1.1 MPa, elongation at break is 21%, bond strength with glass sheet is 0.8 MPa, and coverage after aging is 80%.

[0107] Example 7

[0108] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, the specific steps include:

[0109] (1) Weigh out 30 parts by volume of 1-dodecyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt (purchased from Moni Chemical Technology Co., Ltd.), 0.15 parts of N,N'-methylenebisacrylamide, 0.15 parts of azobisisobutyronitrile, and 70 parts of silane coupling agent modified alumina (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0110] (2) The 1-dodecyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, azobisisobutyronitrile and N,N'-methylenebisacrylamide from step (1) are mixed in a glass bottle and stirred on a long shaft mixer at a stirring speed of 2000 rpm for 3 h to obtain an ionic liquid mixture.

[0111] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 20 min to obtain the mixture.

[0112] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 60°C, and the curing time to 5 hours. After cooling, a polyionic liquid-based thermal interface material is obtained.

[0113] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 1.6 W / (m·K), and its interfacial thermal resistance was 1.99 mm. 2 • K / W, tensile strength is 0.58 MPa, elongation at break is 45%, bond strength with glass sheet is 0.96 MPa, and coverage after aging is 86%.

[0114] Example 8

[0115] This embodiment provides a thermal interface material, the structural schematic diagram of which is shown below. Figure 1 As shown, 1 is the thermal interface material, 11 is the polyionic liquid, and 12 is the thermally conductive filler. The preparation process is as follows: Figure 2 As shown, the specific steps include:

[0116] (1) Weigh out 10 parts by volume of 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.15 parts of N,N'-methylenebisacrylamide, 0.15 parts of benzoyl peroxide, and 90 parts of alumina modified with silane coupling agent (Jiangsu Lianrui New Materials, modified silane coupling agent: vinyltriethoxysilane) with a particle size D50 of 6.1 μm.

[0117] (2) The 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, benzoyl peroxide and N,N'-methylenebisacrylamide from step (1) are mixed in a glass bottle and stirred on a long shaft mixer at a stirring speed of 2000 rpm for 2 h to obtain an ionic liquid mixture.

[0118] (3) Add the silane coupling agent modified alumina to the ionic liquid mixture obtained in step (2), add zirconium beads, and stir in a mixer at a speed of 2000 rpm for 10 min to obtain the mixture.

[0119] (4) Pour the mixture obtained in step (3) into a specific mold, place it in an oven, set the oven temperature to 100℃, and the curing time to 4h. After cooling, the polyionic liquid-based thermal interface material is obtained.

[0120] The thermal interface material prepared in this embodiment was tested for its thermal conductivity, tensile properties, and adhesive properties. Its thermal conductivity was 2.6 W / (m·K), and its interfacial thermal resistance was 3.14 mm. 2 • K / W, tensile strength is 1.3 MPa, elongation at break is 18%, bond strength with glass sheet is 0.44 MPa, and coverage after aging is 76%.

[0121] Example 9

[0122] The difference from Example 1 is that the silane coupling agent used for modifying alumina is vinyltrimethoxysilane; all other raw materials and preparation steps are the same. The material prepared in this comparative example was tested and found to have a thermal conductivity of 1.7 W / (m·K) and an interfacial thermal resistance of 1.97 mm. 2 • K / W, tensile strength is 0.66 MPa, elongation at break is 42%, bond strength with glass sheet is 0.99 MPa, and coverage after aging is 90%.

[0123] Comparative Example 1

[0124] The difference from Example 1 is that no crosslinking agent was added; all other raw materials and preparation steps were the same. Testing showed that the material prepared in this comparative example had a thermal conductivity of 1.6 W / (m·K), a tensile strength of 0.51 MPa, an elongation at break of 28%, an adhesion strength to the glass sheet of 0.68 MPa, and a coverage rate of 83% after aging. Compared to Example 1, the thermal conductivity and mechanical properties of the material significantly decreased, indicating that the addition of the crosslinking agent plays an important role in improving the material's performance.

[0125] Comparative Example 2

[0126] The difference from Example 1 is that the ionic liquid is pre-polymerized, and then a thermally conductive pad is prepared by solution method according to the method reported in patent CN118667278A. The thermal conductivity of the prepared thermally conductive pad is 1.6 W / (m·K), and the interfacial thermal resistance is 3.80 mm. 2The thermal conductivity (K / W) is 0.63 MPa, the tensile strength is 45%, the elongation at break is 45%, the adhesion strength to the glass sheet is 0.95 MPa, and the coverage after aging is 82%. This indicates that the solvent-free method used in this invention to prepare the thermally conductive gel can achieve a lower interfacial thermal resistance than the solvent-based method for preparing thermally conductive pads, effectively improving thermal conductivity and interfacial adhesion.

[0127] Comparative Example 3

[0128] The difference from Example 1 is that no initiator was added; all other raw materials and preparation steps were the same. Testing showed that the material prepared in this comparative example could not be cured, indicating that the initiator plays a crucial role in the polymerization reaction, promoting the polymerization of the vinylimidazole ionic liquid.

[0129] Comparative Example 4

[0130] The difference from Example 1 is that the alumina used in this comparative example was not treated with a silane coupling agent. After mixing in a mixer, agglomerated alumina lumps were obtained, meaning that the material could not be flowed after mixing in the mixer and could not be used for the next dispensing process.

[0131] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the thermal interface material, its preparation method, and its application. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A thermal interface material based on vinylimidazole ionic liquid, characterized in that, The raw materials for preparing the thermal interface material include the following components: vinylimidazolium ionic liquid, thermally conductive filler surface-treated with silane coupling agent, initiator, and crosslinking agent.

2. The thermal interface material according to claim 1, characterized in that, The cation of the vinylimidazolium ionic liquid is selected from any one or a combination of at least two of the following cations: (1-acetonitrile-3-vinylimidazolium), (1-ethyl-3-vinylimidazolium), (1-butyl-3-vinylimidazolium), (1-octyl-3-vinylimidazolium), (1-dodecyl-3-vinylimidazolium), (1-(2-(ethoxy)ethyl)-3-vinylimidazolium), (1-(2-(2-ethoxyethoxy)ethyl)-3-vinylimidazolium), (1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium); The anion of the vinylimidazolium ionic liquid is selected from any one of the following anions: bis(trifluoromethanesulfonyl)imide anion, trifluoromethanesulfonic acid anion, tetrafluoroborate anion, hexafluorophosphate anion, chloride ion, or bromide ion. Preferably, the vinylimidazolium ionic liquid is 1-(2-(2-(2-ethoxyethoxy)ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-vinyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-vinylimidazolium tetrafluoroborate, 1-dodecyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt, or 1-(2-(ethoxy)ethyl)-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide salt.

3. The thermal interface material according to claim 1 or 2, characterized in that, The silane coupling agent is selected from any one or a combination of at least two of the following: γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropyltriethoxysilane, vinyltriethoxysilane, vinyltriethoxysilane, vinyltritert-butylperoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, bis-[3-(triethoxysilyl)propyl]tetrasulfide, γ-ureapropyltriethoxysilane, γ-isocyanate-propyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane quaternary ammonium salt, and tridecafluorooctyltrimethoxysilane. Preferably, the thermally conductive filler is selected from one or a combination of at least two of the following: metallic thermally conductive fillers, ceramic thermally conductive fillers, or carbon-based thermally conductive fillers. Preferably, the metallic thermally conductive filler is selected from any one or a combination of at least two of liquid metal, gold, silver, copper, or aluminum; Preferably, the ceramic thermally conductive filler is selected from any one or a combination of at least two of aluminum nitride, aluminum oxide, zinc oxide, or boron nitride; Preferably, the carbon-based thermally conductive filler is selected from any one or a combination of at least two of silicon carbide, graphene, or carbon nanotubes; Preferably, the volume ratio between the vinylimidazole ionic liquid and the thermally conductive filler is 1:(1-99), more preferably 1:(2-10).

4. The thermal interface material according to any one of claims 1-3, characterized in that, The initiator is any one or a combination of at least two of the following: azobisisobutyronitrile, methyl azobisisobutyrate, azobis(2-methylpropionitrile), diisopropyl azodicarbonate, azodicarbonamide, dicumyl peroxide, tert-butyl peroxide, hydrogen peroxide, lauric acid peroxide, benzoyl peroxide, dibenzoyl peroxide, tert-butyl peroxide (2-ethylhexanoate), ammonium persulfate / sodium bisulfite, 2-hydroxy-2-methyl-1-phenylpropanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, or ethyl 2,4,6-trimethylbenzoylphenylphosphonate. Preferably, the volume ratio of the vinylimidazole ionic liquid to the initiator is 1000:(1-100), more preferably 1000:(1-10).

5. The thermal interface material according to any one of claims 1-4, characterized in that, The crosslinking agent is any one or a combination of at least two of N,N'-methylenebisacrylamide, maleimide, hexamethylene diisocyanate, triisocyanate, glycidyl acrylate, polyethylene glycol diacrylate, neopentyl glycerol triacrylate, pentaerythritol tetraacrylate, divinylbenzene, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, terephthalate diacrylate, bisphenol A diacrylate, diethylenetriamine, or ethylene glycol dimethacrylate, and is more preferably N,N'-methylenebisacrylamide or polyethylene glycol diacrylate; Preferably, the volume ratio of the vinylimidazole ionic liquid to the crosslinking agent is 1000:(1-100), more preferably 1000:(1-10).

6. The thermal interface material according to any one of claims 1-5, characterized in that, The raw materials for preparing the thermal interface material also include additives; Preferably, the additives include one or a combination of at least two of the following: dispersants, wetting agents, flow aids, coupling agents, stabilizers, anti-aging agents, thixotropic agents, thickeners, toughening agents, or other additives; Preferably, the dispersant comprises any one or a combination of at least two of the following: alkylsilane coupling agents, aminopropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, polyether-modified polysiloxane, polycarboxylate dispersants, quaternary ammonium salt surfactants, or sulfosuccinate surfactants. Preferably, the wetting agent or the flow aid comprises any one or a combination of at least two of the following: polydimethylsiloxane, modified polyether polyol, polyethylene glycol and its ether derivatives, phosphate ester wetting agents, silicone oil modified leveling agents, and nonionic surfactants. Preferably, the coupling agent comprises any one or a combination of at least two of γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, isocyanate-functionalized silane, 3-mercaptopropyltrimethoxysilane, octadecyltrimethoxysilane, or allyltrimethoxysilane; Preferably, the stabilizer or anti-aging agent includes hindered phenolic antioxidants, phosphite antioxidants, ultraviolet absorbers, and peroxide decomposition inhibitors; Preferably, the thixotropic agent or thickener includes any one or a combination of at least two of bentonite, fumed silica, polyamide wax, and polyurethane rheology modifier; Preferably, the toughening agent includes any one or a combination of at least two of the following: carboxylated nitrile rubber, polyacrylate rubber, maleic anhydride-grafted ethylene propylene rubber, block copolymer thermoplastic elastomer, hydroxyl-terminated polyether polyol, polycarbonate polyol, and acrylate core-shell toughening agent. Preferably, the other additives include any one or a combination of at least two of the following: aluminum hydroxide, antimony trioxide, phosphate ester flame retardants, color modifiers, or polysiloxane release agents.

7. A method for preparing a thermal interface material based on vinylimidazole ionic liquid according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Mix vinylimidazolium ionic liquid with crosslinking agent and initiator to obtain ionic liquid mixture; (2) Add the thermally conductive filler that has been surface-treated with silane coupling agent to the ionic liquid mixture obtained in step (1), mix evenly, add optional additives, and obtain a mixture; (3) The mixture obtained in step (2) is cured to obtain the thermal interface material based on vinylimidazolium ionic liquid.

8. The preparation method according to claim 7, characterized in that, The mixing time in step (1) is 1-3 hours; Preferably, the mixing in step (2) is performed by mechanical stirring or ultrasonic dispersion; Preferably, the mixing in step (2) is carried out under stirring, the stirring time is 1-20 min, and the stirring rate is 200-3000 r / min; Preferably, the curing temperature in step (3) is 60-100℃ and the curing time is 2-5h.

9. A thermally conductive and heat-dissipating material, characterized in that, The thermally conductive and heat-dissipating material includes the thermal interface material according to any one of claims 1-8.

10. The application of the thermal interface material according to any one of claims 1-6 or the thermally conductive and heat-dissipating material according to claim 9 in a chip.

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