Composite phase change heat-conducting interface material with insulation and efficient heat dissipation performance and preparation process of composite phase change heat-conducting interface material

Abstract

The invention discloses a composite phase change heat conduction interface material with insulation and efficient heat dissipation performance and a preparation process thereof. The composite phase change heat conduction interface material is prepared from, by mass, 40%-60% of a phase change functional matrix, 30%-50% of an insulation heat conduction enhancing system, 3%-8% of a structure supporting and compatibility modifier and 0.5%-2% of an antioxidant. Through dual-scale filler compounding and organic and inorganic interface modification, the heat-conducting property of the material is remarkably improved, meanwhile, the excellent insulating property is guaranteed, sufficient phase change latent heat is maintained, collaborative optimization of insulating, heat-conducting and phase change properties is achieved, the multi-performance requirements of high-power electronic devices for interface materials can be met, and the application prospect is wide. The supporting effect of the modified polyimide micro powder is chemically bonded with an interface, so that the material has no liquid loss after phase change, can still keep better shape integrity and quality stability even after long-term cold and hot circulation, and can adapt to the environmental change in the long-term use process of electronic devices.

Description

Technical Field

[0001] This invention relates to the field of composite phase change thermally conductive interface materials, specifically to a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation performance, and its preparation process. Background Technology

[0002] Thermally conductive phase change materials are thermally conductive interface materials that can change from a solid to a liquid state above a certain formulation design temperature. They are also known as phase change thermally conductive materials. Thermally conductive phase change materials are heat-enhancing polymers designed to minimize the thermal resistance between power-consuming electronic devices and the heat sinks connected to them. This low thermal resistance channel allows the heat sink to achieve optimal performance. Thermally conductive phase change materials have strong interfacial wetting ability and can greatly fill the gaps between the interfaces above the phase change temperature, effectively eliminating air between the interfaces.

[0003] Existing composite phase change materials mostly use paraffin or polyethylene glycol as the phase change matrix. Although they have a certain latent heat storage capacity, their thermal conductivity is generally ≤0.3W / m・K, resulting in high interfacial thermal resistance. This makes them unsuitable for the rapid heat dissipation requirements of high-power devices. Some solutions improve thermal conductivity by adding metal fillers, but at the expense of insulation performance. The composite system has poor compatibility and stability. To balance insulation and thermal conductivity, some technologies use inorganic insulating fillers such as boron nitride and alumina. However, due to the large difference in surface energy between the organic phase change matrix and the inorganic fillers, filler agglomeration and interfacial separation are prone to occur, leading to rapid decay of the material's thermal conductivity. Furthermore, liquid loss is likely after the phase change, resulting in insufficient structural stability and inadequate adaptability to aging. Composite phase change thermal conductive interface materials are subjected to long-term cold and hot cycling environments from -40℃ to 85℃, where the organic phase change matrix is ​​prone to oxidative degradation, leading to the decay of latent heat of phase change and a short service life. Therefore, there is a particular need for a composite phase change thermal conductive interface material and its preparation process that combines insulation and efficient heat dissipation performance. Summary of the Invention

[0004] The purpose of this invention is to provide a composite phase change thermally conductive interface material and its preparation process that combine insulation and high-efficiency heat dissipation performance in order to solve the above-mentioned problems, and to overcome the defects of the prior art, as detailed below.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation performance, characterized in that it is composed of the following components by mass percentage: 40% to 60% phase change functional matrix, 30% to 50% insulation and thermal conductivity enhancement system, 3% to 8% structural support and compatibility modifier, and 0.5% to 2% antioxidant.

[0007] Preferably, the phase change functional matrix is ​​a mixture of polyethylene glycol and fatty acid ester, wherein the molecular weight of the polyethylene glycol is 4000-6000, the fatty acid ester is butyl stearate or methyl palmitate, and the mass ratio of polyethylene glycol to fatty acid ester is 8:2-9:1.

[0008] Preferably, the mass ratio of polyethylene glycol to fatty acid ester is 8.5:1.5.

[0009] Preferably, the insulation and thermal conductivity enhancement system is a dual-scale composite filler of micron-sized boron nitride and nano-sized alumina, wherein the particle size of the micron-sized boron nitride is 5μm-20μm, the particle size of the nano-sized alumina is 50nm-100nm, and the mass ratio of micron-sized boron nitride to nano-sized alumina is 3:1-5:1.

[0010] Preferably, the micron-sized boron nitride has a particle size of 10 μm, the nano-sized alumina has a particle size of 80 nm, and the mass ratio of micron-sized boron nitride to nano-sized alumina is 4:1.

[0011] Preferably, the structural support and compatibility modifier is polyimide micro powder modified with silane coupling agent KH-550, and the amount of silane coupling agent KH-550 is 1% to 3% of the mass of polyimide micro powder.

[0012] Preferably, the amount of the silane coupling agent KH-550 is 1.5% to 2.5% of the mass of the polyimide micro powder.

[0013] Preferably, the antioxidant is hindered phenolic antioxidant 1010 and 1076, and the mass percentage of the antioxidant is 1% to 1.5%.

[0014] A method for preparing a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation properties further includes the following steps:

[0015] Step S1, Packing Pretreatment:

[0016] Micron-sized boron nitride and nano-sized alumina were dried in a vacuum drying oven at 120℃-130℃ for 4 to 6 hours, and then mixed with silane coupling agent KH-550 in a high-speed mixer at a speed of 1500r / min-2000r / min and a temperature of 60℃-80℃ for 15 to 20 minutes to obtain a pretreated insulating and thermally conductive filler.

[0017] Step S2, Preparation of phase change matrix:

[0018] Polyethylene glycol, fatty acid esters, and antioxidants are added to a reaction vessel and stirred for 30 to 40 minutes at a temperature of 70℃-90℃ and a speed of 500 to 800 r / min. Modified polyimide micro powder is then added, and stirring continues for another 20 to 30 minutes to obtain a phase change functional matrix.

[0019] Step S3, Preparation of composite slurry:

[0020] Pretreated insulating and thermally conductive fillers are gradually added to the phase change functional matrix. The mixture is first stirred at a speed of 300 r / min to 500 r / min for 20 minutes, and then ultrasonically dispersed at a power of 300 W to 500 W for 30 to 40 minutes to obtain a composite slurry.

[0021] Step S4, Molding and Curing:

[0022] The composite slurry is poured into a mold and degassed for 20 to 30 minutes under a vacuum of ≤-0.095MPa. Then, it is cured in a segmented temperature-controlled oven: kept at 80℃ for 4 to 5 hours, then heated to 100℃ and kept at 100℃ for 6 to 8 hours. After cooling, it is demolded to obtain the finished product.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention significantly improves the thermal conductivity of materials by combining dual-scale fillers and modifying the interface between organic and inorganic materials, while ensuring excellent insulation performance and maintaining sufficient latent heat of phase change. This achieves synergistic optimization of insulation, thermal conductivity and phase change performance, which can meet the multi-performance requirements of interface materials for high-power electronic devices.

[0025] 2. The modified polyimide micro powder of this invention provides support and interfacial chemical bonding, preventing liquid loss after phase change. Even after long-term thermal cycling, it can maintain good shape integrity and quality stability, making it adaptable to environmental changes during long-term use of electronic devices. Detailed Implementation

[0026] Unless the context clearly indicates otherwise, nouns without quantifiers and nouns modified by “the” include singular and plural indicators of persons / kinds.

[0027] As used in the specification and claims, the terms “comprising,” “including,” “having,” “may,” “containing,” and variations thereof are open transitional phrases, terms, or words that require the presence of a specified ingredient / step and allow the presence of other ingredients / steps. However, such a description should be interpreted as also describing the composition or method as consisting of the ingredients / steps listed “by” and “substantially by,” which allows only the specified ingredient / step and any unavoidable impurities that may arise therefrom to be present, and excludes other ingredients / steps.

[0028] The numerical values ​​in the specification and claims of this application should be understood to include the same numerical values ​​when reduced to the same number of significant figures and numerical values ​​that differ from the stated values ​​by less than the experimental error of conventional measurement techniques used to determine the stated values ​​of the type described in this application.

[0029] All ranges disclosed herein include the indicated endpoints and can be combined independently (e.g., the range “2 g to 10 g” includes the endpoints 2 g and 10 g, as well as all intermediate values).

[0030] The terms “about” and “approximately” can be used to include any numerical value that may vary without altering its fundamental function. When used with a range, “about” and “approximately” also disclose a range defined by the absolute values ​​of its two endpoints; for example, “about 2 to about 4” also discloses a range of “2 to 4”. Typically, the terms “about” and “approximately” can refer to ±10% of the indicated number. However, for temperature, the term “approximately” refers to ±1°C.

[0031] Unless otherwise expressly stated, the percentage of elements shall be considered as the weight percentage of the alloy.

[0032] This disclosure may relate to temperatures for certain method steps. It should be noted that these parameters generally refer to the temperature set by the heat source (such as a furnace), and not necessarily the temperature that the heated material must reach.

[0033] The following description is intended to disclose the present invention and to enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious modifications will be apparent to those skilled in the art. The basic principles of the invention defined in the following description can be used in other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0034] The present invention provides a technical solution: a composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation performance, which is composed of the following components by mass percentage: 40% to 60% phase change functional matrix, 30% to 50% insulation and thermal conductivity enhancement system, 3% to 8% structural support and compatibility modifier, and 0.5% to 2% antioxidant.

[0035] Furthermore, the phase change functional matrix is ​​a mixture of polyethylene glycol and fatty acid esters, with the polyethylene glycol having a molecular weight of 4000-6000 and the fatty acid esters being butyl stearate or methyl palmitate, and the mass ratio of polyethylene glycol to fatty acid esters being 8:2-9:1.

[0036] Furthermore, the mass ratio of polyethylene glycol to fatty acid ester is 8.5:1.5.

[0037] Furthermore, the insulation and thermal conductivity enhancement system is a dual-scale composite filler of micron-sized boron nitride and nano-sized alumina. The particle size of micron-sized boron nitride is 5μm-20μm, and the particle size of nano-sized alumina is 50nm-100nm. The mass ratio of micron-sized boron nitride to nano-sized alumina is 3:1-5:1.

[0038] Furthermore, the micron-sized boron nitride has a particle size of 10 μm, the nano-sized alumina has a particle size of 80 nm, and the mass ratio of micron-sized boron nitride to nano-sized alumina is 4:1.

[0039] Furthermore, the structural support and compatibility modifier is polyimide micro powder modified with silane coupling agent KH-550, and the amount of silane coupling agent KH-550 is 1% to 3% of the mass of polyimide micro powder.

[0040] Furthermore, the amount of silane coupling agent KH-550 used is 1.5% to 2.5% of the mass of polyimide micro powder.

[0041] Furthermore, the antioxidants are hindered phenolic antioxidants 1010 and 1076, with an antioxidant mass percentage of 1% to 1.5%.

[0042] A method for preparing a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation properties further includes the following steps:

[0043] Step S1, Packing Pretreatment:

[0044] Micron-sized boron nitride and nano-sized alumina were dried in a vacuum drying oven at 120℃-130℃ for 4 to 6 hours, and then mixed with silane coupling agent KH-550 in a high-speed mixer at a speed of 1500r / min-2000r / min and a temperature of 60℃-80℃ for 15 to 20 minutes to obtain a pretreated insulating and thermally conductive filler.

[0045] Step S2, Preparation of phase change matrix:

[0046] Polyethylene glycol, fatty acid esters, and antioxidants are added to a reaction vessel and stirred for 30 to 40 minutes at a temperature of 70℃-90℃ and a speed of 500 to 800 r / min. Modified polyimide micro powder is then added, and stirring continues for another 20 to 30 minutes to obtain a phase change functional matrix.

[0047] Step S3, Preparation of composite slurry:

[0048] Pretreated insulating and thermally conductive fillers are gradually added to the phase change functional matrix. The mixture is first stirred at a speed of 300 r / min to 500 r / min for 20 minutes, and then ultrasonically dispersed at a power of 300 W to 500 W for 30 to 40 minutes to obtain a composite slurry.

[0049] Step S4, Molding and Curing:

[0050] The composite slurry is poured into a mold and degassed for 20 to 30 minutes under a vacuum of ≤-0.095MPa. Then, it is cured in a segmented temperature-controlled oven: kept at 80℃ for 4 to 5 hours, then heated to 100℃ and kept at 100℃ for 6 to 8 hours. After cooling, it is demolded to obtain the finished product.

[0051] The specific steps are as follows: Micron-sized boron nitride and nano-sized alumina are dried in a vacuum drying oven at 120℃-130℃ for 4-6 hours. Then, they are mixed with silane coupling agent KH-550 in a high-speed mixer at a speed of 1500-2000 r / min and a temperature of 60℃-80℃ for 15-20 minutes to obtain a pretreated insulating and thermally conductive filler. Polyethylene glycol, fatty acid esters, and antioxidants are added to a reaction vessel and stirred for 30-40 minutes at a temperature of 70℃-90℃ and a speed of 500-800 r / min. Modified polyimide micropowder is then added, followed by... Continue stirring for 20-30 minutes to obtain the phase change functional matrix. Gradually add pretreated insulating and thermally conductive filler to the phase change functional matrix. First, stir at a speed of 300-500 r / min for 20 minutes, then use ultrasonic dispersion with a power of 300W-500W for 30-40 minutes to obtain a composite slurry. Pour the composite slurry into a mold and degas for 20-30 minutes under a vacuum degree ≤-0.095MPa. Then, cure in stages at controlled temperature in an oven: keep at 80℃ for 4-5 hours, then raise the temperature to 100℃ and keep at 6-8 hours. Cool and demold to obtain the finished product.

[0052] Example 1

[0053] A composite phase change thermally conductive interface material that combines insulation and efficient heat dissipation properties is composed of the following components by mass percentage:

[0054] Phase change functional matrix: 45g polyethylene glycol with a molecular weight of 6000, 5g butyl stearate, mass ratio 9:1, total proportion 50%;

[0055] Insulation and thermal conductivity enhancement system: 35g of micron-sized boron nitride with a particle size of 10μm and 8.75g of nano-sized alumina with a particle size of 80nm, with a mass ratio of 4:1 and a total proportion of 43.75%;

[0056] Structural support and compatibility modifier: 5g of 3μm polyimide micropowder modified with 2% silane coupling agent KH-550, accounting for 5% of the total composition;

[0057] Antioxidants: 10100.6g antioxidant and 10760.65g antioxidant, accounting for 1.25% of the total.

[0058] A method for preparing a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation properties further includes the following steps:

[0059] Step S1, Packing Pretreatment:

[0060] 35g of micron-sized boron nitride and 8.75g of nano-sized alumina were dried in a vacuum drying oven at 125℃ and -0.095MPa for 5 hours, and the moisture content was measured to be 0.08%. 0.1g of silane coupling agent KH-550 was added and mixed in a high-speed mixer at 1800r / min and 70℃ for 18 minutes to obtain the pretreated filler. Infrared spectroscopy showed that the coupling agent coating was successful.

[0061] Step S2, Preparation of phase change matrix:

[0062] Add 45g of polyethylene glycol and 5g of butyl stearate to the reactor and stir at 80℃ and 600r / min for 35 minutes; add 0.6g of antioxidant 1010 and 0.65g of antioxidant 1076 and stir for 10 minutes; add 5g of modified polyimide micro powder and continue stirring for 25 minutes to obtain a phase change functional matrix with uniform appearance and no particle agglomeration.

[0063] Step S3, Preparation of composite slurry:

[0064] The pretreated filler was added to the phase change functional matrix in 5 batches, with 9.75 g added each time. The mixture was stirred at 400 r / min for 20 minutes. It was then dispersed using 400 W ultrasonic waves for 35 minutes. The filler dispersion was measured to be 3 μm by a laser particle size analyzer, and there was no agglomeration, thus obtaining the composite slurry.

[0065] Step S4, Molding and Curing:

[0066] Pour the slurry into a 50mm×50mm×2mm polytetrafluoroethylene mold, degas under vacuum at -0.098MPa for 25 minutes; keep warm at 80℃ for 4.5 hours, and at 100℃ for 7 hours; after cooling to room temperature, demold to obtain the finished product.

[0067] Performance testing:

[0068] Thermal conductivity: tested using the hot wire method, 2.2 W / m·K;

[0069] Volume resistivity: measured with a high-resistivity meter, 6.2 × 10¹ 4 Ω・cm;

[0070] Phase change characteristics: Differential scanning calorimetry was used for testing. The phase change temperature was 52℃ and the latent heat of phase change was 208 J / g.

[0071] Cyclic stability: After 500 cycles of thermal cycling from -40℃ to 85℃, the latent heat of phase change decay rate is 3.1%, the mass loss rate is 2.0%, and the deformation is 4.5%.

[0072] The specific steps are as follows: 35g of micron-sized boron nitride and 8.75g of nano-sized alumina were dried in a vacuum drying oven at 125℃ and -0.095MPa for 5 hours, and the moisture content was measured to be 0.08%; 0.1g of silane coupling agent KH-550 was added, and the mixture was mixed in a high-speed mixer at 1800r / min and 70℃ for 18 minutes to obtain the pretreated filler. Infrared spectroscopy showed that the coupling agent coating was successful. 45g of polyethylene glycol and 5g of butyl stearate were added to the reaction vessel and stirred at 80℃ and 600r / min for 35 minutes; 0.6g of antioxidant 1010 and 0.65g of antioxidant 1076 were added and stirred for 10 minutes. Add 5g of modified polyimide micro powder and continue stirring for 25 minutes to obtain a phase change functional matrix with uniform appearance and no particle agglomeration. Add 9.75g of pretreated filler to the phase change functional matrix in 5 batches, stirring at 400r / min for 20 minutes each time. Disperse the filler using 400W ultrasonic for 35 minutes. The filler dispersion is measured to be 3μm by a laser particle size analyzer, with no agglomeration, to obtain a composite slurry. Pour the slurry into a 50mm×50mm×2mm polytetrafluoroethylene mold and degas under vacuum at -0.098MPa for 25 minutes. Keep warm at 80℃ for 4.5 hours and at 100℃ for 7 hours. Demold after cooling to room temperature to obtain the finished product.

[0073] Example 2

[0074] A composite phase change thermally conductive interface material that combines insulation and efficient heat dissipation properties is composed of the following components by mass percentage:

[0075] Phase change functional matrix: 50g polyethylene glycol with a molecular weight of 4000, 5g methyl palmitate, mass ratio 10:1, total proportion 55%;

[0076] Insulation and thermal conductivity enhancement system: 28g of micron-sized boron nitride with a particle size of 5μm and 7g of nano-sized alumina with a particle size of 50nm, with a mass ratio of 4:1 and a total proportion of 35%;

[0077] Structural support and compatibility modifier: 8g of 2μm polyimide micropowder modified with 1.5% silane coupling agent KH-550, accounting for 8% of the total content;

[0078] Antioxidants: 10100.5g antioxidant and 10761.5g antioxidant, accounting for 2% of the total.

[0079] A method for preparing a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation properties further includes the following steps:

[0080] Step S1, Packing Pretreatment:

[0081] Micron-sized boron nitride and nano-sized alumina were dried under vacuum at 120℃ and -0.09MPa for 4 hours, with a moisture content of 0.09%. 0.12g of silane coupling agent KH-550 was added, and the mixture was stirred at 1500r / min and 60℃ for 15 minutes to obtain the pretreated filler.

[0082] Step S2, Preparation of phase change matrix:

[0083] Polyethylene glycol and methyl palmitate were stirred at 70°C and 500 r / min for 40 minutes; 0.5 g of antioxidant 1010 and 1.5 g of antioxidant 1076 were added and stirred for 10 minutes; 8 g of modified polyimide micro powder was added and stirred for another 30 minutes to obtain the phase change functional matrix.

[0084] Step S3, Preparation of composite slurry:

[0085] The pretreated filler was added to the phase change functional matrix in four batches, with 8.75 g added each time. The mixture was stirred at 300 r / min for 20 minutes and then dispersed using 300 W ultrasonic waves for 40 minutes to obtain the composite slurry.

[0086] Step S4, Molding and Curing:

[0087] Pour the slurry into a 50mm×50mm×2mm polytetrafluoroethylene mold, degas under vacuum at -0.095MPa for 30 minutes, keep warm at 80℃ for 5 hours, keep warm at 100℃ for 8 hours, and then demold after cooling to room temperature to obtain the finished product.

[0088] Performance testing

[0089] Thermal conductivity: tested using the hot wire method, 1.8 W / m·K;

[0090] Volume resistivity: measured with a high-resistivity meter, 8.5 × 10¹ 4 Ω・cm;

[0091] Phase change characteristics: Differential scanning calorimetry was used to test the phase change temperature at 46℃ and the latent heat of phase change at 195 J / g.

[0092] Cyclic stability: After 500 cycles of heating and cooling from -40℃ to 85℃, the latent heat of phase change decay rate is 4.2%, the mass loss rate is 2.7%, and the deformation is 6.8%.

[0093] The specific steps are as follows: Micron-sized boron nitride and nano-sized alumina are vacuum dried at 120℃ and -0.09MPa for 4 hours, with a moisture content of 0.09%. 0.12g of silane coupling agent KH-550 is added, and the mixture is stirred at 1500r / min and 60℃ for 15 minutes to obtain the pretreated filler. Polyethylene glycol and methyl palmitate are stirred at 70℃ and 500r / min for 40 minutes. 0.5g of antioxidant 1010 and 1.5g of antioxidant 1076 are added, and the mixture is stirred for 10 minutes. 8g of modified... Polyimide micro powder was stirred for another 30 minutes to obtain a phase change functional matrix. Pretreated filler was added to the phase change functional matrix in four batches, 8.75 g each time, and stirred at 300 r / min for 20 minutes. The mixture was then ultrasonically dispersed at 300 W for 40 minutes to obtain a composite slurry. The slurry was poured into a 50 mm × 50 mm × 2 mm polytetrafluoroethylene mold and degassed under vacuum at -0.095 MPa for 30 minutes. The mold was then heated at 80 °C for 5 hours and at 100 °C for 8 hours. After cooling to room temperature, the mold was removed to obtain the finished product.

[0094] Example 3

[0095] A composite phase change thermally conductive interface material that combines insulation and efficient heat dissipation properties is composed of the following components by mass percentage:

[0096] Phase change functional matrix: 48g of polyethylene glycol with a molecular weight of 5500 and 4g of methyl palmitate, with a mass ratio of 12:1 and a total proportion of 52%. Polyethylene glycol with a molecular weight of 5500 is selected to meet the thermal management requirements of electronic devices in the medium temperature range. The reduced proportion of methyl palmitate can improve the hardness of the material after phase change and reduce the risk of deformation.

[0097] Insulation and thermal conductivity enhancement system: 32g of micron-sized boron nitride with a particle size of 15μm and 8g of nano-sized alumina with a particle size of 70nm, with a mass ratio of 4:1 and a total proportion of 40%; the micron-sized boron nitride particle size is increased to 15μm to enhance the continuity of the thermal conductivity path, and the nano-sized alumina is selected with a particle size of 70nm to balance the dispersibility and thermal conductivity assistance effect.

[0098] Structural support and compatibility modifier: 5g of 4μm polyimide micropowder modified with 2.2% silane coupling agent KH-550, accounting for 5%; the micropowder particle size is slightly increased to further enhance the structural support effect, and the amount of coupling agent is adjusted to 2.2% to optimize the bonding strength between organic and inorganic interfaces;

[0099] Antioxidants: Antioxidant 1010 0.8g, antioxidant 1076 0.2g, total proportion 1%; adjust the antioxidant compounding ratio, increase the amount of macromolecular antioxidant 1010, and improve the material's anti-aging ability under long-term high temperature environment.

[0100] A method for preparing a composite phase change thermally conductive interface material that combines insulation and high-efficiency heat dissipation properties further includes the following steps:

[0101] Step S1, Packing Pretreatment:

[0102] 32g of boron nitride with a particle size of 15μm and 8g of alumina with a particle size of 70nm were dried in a vacuum drying oven at 128℃ and -0.092MPa for 5.5 hours to ensure that the surface moisture of the large-particle boron nitride was fully removed. 0.11g of silane coupling agent KH-550 was added, calculated as 2.2% of the mass of polyimide micro powder, and mixed in a high-speed mixer at 1700r / min and 75℃ for 17 minutes. The speed and temperature were adjusted to meet the coating requirements of the large-particle filler to obtain a pretreated insulating and thermally conductive filler. Scanning electron microscopy showed that the coupling agent coating on the filler surface was uniform and there was no obvious agglomeration.

[0103] Step S2, Preparation of phase change matrix:

[0104] 48g of polyethylene glycol (molecular weight 5500) and 4g of methyl palmitate were added to a reactor and stirred for 38 minutes at 85℃ and 650r / min. Increasing the temperature and speed promoted the melting and mixing of high molecular weight polyethylene glycol and methyl palmitate. 0.8g of antioxidant 1010 and 0.2g of antioxidant 1076 were added, and stirring was continued for 12 minutes to extend the antioxidant dispersion time and ensure uniformity. Subsequently, 5g of modified polyimide micropowder was added and stirred for 28 minutes to obtain the phase change functional matrix. The matrix appeared as a uniform milky white fluid with no visible particles.

[0105] Step S3, Preparation of composite slurry:

[0106] Pretreated insulating and thermally conductive filler was added to the phase change functional matrix in six separate additions of 6.67g each time to reduce the amount added at one time and avoid agglomeration of large-diameter filler particles. The mixture was first stirred at 450r / min for 20 minutes, and then ultrasonically dispersed for 38 minutes with a power of 450W to increase the ultrasonic power and time, thereby breaking up any weak agglomerations that might form from the large-diameter filler particles, resulting in a composite slurry. The filler dispersion in the slurry was measured to be 4.2μm using a laser particle size analyzer, which met the requirement of no agglomeration.

[0107] Step S4, Molding and Curing:

[0108] The composite slurry was poured into a 60mm×60mm×1.5mm polytetrafluoroethylene mold and degassed for 28 minutes under a vacuum of -0.096MPa. Then it was placed in an oven and cured using segmented temperature control: 80℃ for 4.8 hours, then the temperature was raised to 100℃ for 7.5 hours, and the holding time was finely adjusted to ensure that the thin material was fully cured. After cooling to room temperature, it was demolded to obtain a thin composite phase change thermally conductive interface material. The finished product had a smooth surface without cracks or bubbles.

[0109] Performance testing:

[0110] Thermal conductivity: Tested using the hot wire method, the thermal conductivity reaches 2.0 W / m·K due to the more continuous heat conduction path formed by the large-particle boron nitride, which meets the heat dissipation requirements of medium and high power electronic devices.

[0111] Volume resistivity: Measured using a high-resistivity meter, the result is 7.8 × 10¹ 4 Ω・cm, excellent insulation performance, suitable for high-voltage electronic scenarios;

[0112] Phase change characteristics: The phase change temperature is 56℃, which is suitable for medium-temperature working environments such as automotive electronics. The latent heat of phase change is 198J / g, which is sufficient.

[0113] Cyclic stability: After 500 cycles of heating and cooling from -40℃ to 85℃, due to the increased dosage of antioxidant 1010, the latent heat of phase change decay rate is only 2.9%, the mass loss rate is 1.8%, and the deformation is 5.2%. The structural and performance stability is outstanding, meeting the requirements for long-term outdoor or harsh environments.

[0114] The specific steps are as follows: 32g of micron-sized boron nitride (15μm particle size) and 8g of nano-sized alumina (70nm particle size) are placed in a vacuum drying oven at 128℃ and -0.092MPa for 5.5 hours to ensure sufficient removal of surface moisture from the large-particle boron nitride; 0.11g of silane coupling agent KH-550 is added, calculated as 2.2% of the mass of polyimide micro powder, and mixed in a high-speed mixer at 1700r / min and 75℃ for 17 minutes. The speed and temperature are adjusted to suit the coating requirements of the large-particle filler, resulting in... Pre-treated insulating and thermally conductive filler; scanning electron microscopy showed that the coupling agent coating on the filler surface was uniform and without obvious agglomeration. 48g of polyethylene glycol (molecular weight 5500) and 4g of methyl palmitate were added to the reactor and stirred for 38 minutes at 85℃ and 650 rpm. Increasing the temperature and speed promoted the melting and mixing of high molecular weight polyethylene glycol and methyl palmitate. 0.8g of antioxidant 1010 and 0.2g of antioxidant 1076 were added, and stirring continued for 12 minutes to extend the antioxidant dispersion time and ensure uniformity. Then, 5g of [unspecified ingredient] was added... Modified polyimide micropowder was stirred for 28 minutes to obtain a phase change functional matrix. The matrix appeared as a uniform milky white fluid with no visible particles. Pretreated insulating and thermally conductive filler was added to the phase change functional matrix in six separate additions of 6.67 g each time to reduce the amount added at one time and avoid agglomeration of large-diameter filler particles. The mixture was first stirred at 450 r / min for 20 minutes, followed by ultrasonic dispersion treatment with 450 W for 38 minutes. Increasing the ultrasonic power and time broke up any weak agglomerations that might form from large-diameter filler particles, resulting in a composite slurry. The slurry was then inspected using a laser particle size analyzer. The filler dispersion in the slurry was measured to be 4.2 μm, meeting the requirement of no agglomeration. The composite slurry was poured into a 60 mm × 60 mm × 1.5 mm polytetrafluoroethylene mold and degassed for 28 minutes under a vacuum of -0.096 MPa. Then it was placed in an oven and cured by segmented temperature control: 80℃ for 4.8 hours, then heated to 100℃ for 7.5 hours, with fine-tuning of the holding time to ensure that the thin material was fully cured. After cooling to room temperature, it was demolded to obtain a thin composite phase change thermally conductive interface material. The surface of the finished product was smooth and free of cracks and bubbles.

[0115] Those skilled in the art should understand that the embodiments of the present invention shown in the above description are merely examples and do not limit the present invention. The object of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been shown and explained in the embodiments. Without departing from the stated principles, the implementation of the present invention can have any variations or modifications. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. These specific embodiments are merely explanations of this application and are not limitations thereof. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of this application.

Claims

1. A composite phase change thermally conductive interface material possessing both insulation and high-efficiency heat dissipation properties, characterized in that, It is composed of the following components by mass percentage: 40%–60% phase change functional matrix, 30%–50% insulation and thermal conductivity enhancement system, 3%–8% structural support and compatibility modifier, and 0.5%–2% antioxidant.

2. The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 1, characterized in that: The phase change functional matrix is ​​a mixture of polyethylene glycol and fatty acid esters. The polyethylene glycol has a molecular weight of 4000-6000, and the fatty acid ester is butyl stearate or methyl palmitate. The mass ratio of polyethylene glycol to fatty acid ester is 8:2-9:

1.

3. The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 2, characterized in that: The mass ratio of polyethylene glycol to fatty acid ester is 8.5:1.

5.

4. The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 1, characterized in that: The insulation and thermal conductivity enhancement system is a dual-scale composite filler of micron-sized boron nitride and nano-sized alumina. The particle size of the micron-sized boron nitride is 5μm-20μm, and the particle size of the nano-sized alumina is 50nm-100nm. The mass ratio of micron-sized boron nitride to nano-sized alumina is 3:1-5:

1.

5. A composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 4, characterized in that: The micron-sized boron nitride has a particle size of 10 μm, the nano-sized alumina has a particle size of 80 nm, and the mass ratio of micron-sized boron nitride to nano-sized alumina is 4:

1.

6. The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 1, characterized in that: The structural support and compatibility modifier is polyimide micro powder modified with silane coupling agent KH-550, and the amount of silane coupling agent KH-550 is 1% to 3% of the mass of polyimide micro powder.

7. A composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties as described in claim 6, characterized in that: The amount of the silane coupling agent KH-550 is 1.5% to 2.5% of the mass of the polyimide micro powder.

8. The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties according to claim 1, characterized in that: The antioxidants are hindered phenolic antioxidants 1010 and 1076, and the mass percentage of the antioxidants is 1% to 1.5%.

9. A method for preparing a composite phase change thermally conductive interface material possessing both insulation and high-efficiency heat dissipation properties, characterized in that, The composite phase change thermally conductive interface material with both insulation and high-efficiency heat dissipation properties, applied to any one of claims 1-8, further includes the following steps: Step S1, Packing Pretreatment: Micron-sized boron nitride and nano-sized alumina were dried in a vacuum drying oven at 120℃-130℃ for 4 to 6 hours, and then mixed with silane coupling agent KH-550 in a high-speed mixer at a speed of 1500r / min-2000r / min and a temperature of 60℃-80℃ for 15 to 20 minutes to obtain a pretreated insulating and thermally conductive filler. Step S2, Preparation of phase change matrix: Polyethylene glycol, fatty acid esters and antioxidants are added to a reaction vessel and stirred for 30 to 40 minutes at a temperature of 70℃-90℃ and a speed of 500 r / min-800 r / min. Modified polyimide micro powder is then added and stirring is continued for 20 to 30 minutes to obtain a phase change functional matrix. Step S3, Preparation of composite slurry: Pretreated insulating and thermally conductive filler is gradually added to the phase change functional matrix. First, the mixture is stirred at a speed of 300 r / min-500 r / min for 20 minutes, and then ultrasonically dispersed at a power of 300 W-500 W for 30 minutes-40 minutes to obtain a composite slurry. Step S4, Molding and Curing: The composite slurry is poured into a mold and degassed for 20 to 30 minutes under a vacuum of ≤-0.095MPa. Then, it is cured in a segmented temperature-controlled oven: kept at 80℃ for 4 to 5 hours, then heated to 100℃ and kept at 100℃ for 6 to 8 hours. After cooling, it is demolded to obtain the finished product.