Highly heat-conductive insulating resin composition, highly heat-conductive insulating film, and method for producing the same

Abstract

The application relates to the technical field of heat-conducting materials, in particular to a high-heat-conducting insulating resin composition, a high-heat-conducting insulating film and a preparation method thereof. The high-heat-conducting insulating resin composition comprises the following components in parts by weight: 40-80 parts of epoxy resin and 20-60 parts of heat-conducting fillers; wherein the heat-conducting fillers comprise a composite material of tabular corundum and cubic boron nitride, cubic boron arsenide and flaky hexagonal boron nitride. The high-heat-conducting insulating resin composition is constructed by using heat-conducting fillers with different particle sizes in the forms of flakes and spherical particles to form a complete heat-conducting network; the heat-conducting coefficient of the designed epoxy resin-heat-conducting filler system is high, the system shows high heat conduction and good insulation, and the system can overcome the defects of poor mechanical properties and poor heat resistance of traditional heat-conducting films.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductive materials, and in particular to a high thermal conductive insulating resin composition, a high thermal conductive insulating film and a preparation method thereof. Background Art

[0002] In recent years, microelectronics integration and assembly technologies have advanced rapidly. Electronic devices and components have become increasingly miniaturized and multifunctional, leading to a dramatic increase in operating frequencies. Heat generated during operation rapidly accumulates, causing ambient temperatures to rise continuously. If this accumulated heat cannot be dissipated promptly, it will significantly impact the reliability of the devices and components, shortening their service life. Therefore, to ensure the smooth and efficient operation of devices and components, timely heat dissipation has become a pressing issue in the field of microelectronics packaging. Currently, the most common approach is to use thermally conductive materials with high thermal conductivity to dissipate heat in a timely manner, thereby ensuring the proper operation of equipment. Among these, polymer-based thermally conductive composite materials are the most widely used due to their excellent processability and low cost.

[0003] Epoxy resin is the most commonly used polymer matrix due to its excellent electrical insulation, thermal, and mechanical properties, as well as its simple molding process, low viscosity, and minimal shrinkage during curing. However, epoxy resin has a low thermal conductivity (0.18W / mK), and thermally conductive fillers are often added to improve the thermal conductivity of the composite material. There are two main approaches to improving the thermal conductivity of thermally conductive films: 1) adjusting the molecular structure of the epoxy resin polymer itself to reduce defects such as molecular and lattice vibration disharmony to achieve high crystallinity or orientation, ultimately reducing phonon scattering; and 2) filling the epoxy resin with highly thermally conductive particles such as boron nitride, silicon nitride, and aluminum nitride, with boron nitride being the most commonly used filler.

[0004] Chinese patent application CN 109280332 A discloses a boron nitride / epoxy resin thermally conductive and insulating composite material. The invention patent application describes surface modification of boron nitride using a silane coupling agent. The modified flaky hexagonal boron nitride powder and cubic boron nitride powder are then filled into epoxy resin in a specific ratio. The resulting composite material exhibits improved thermal conductivity, but the improvement remains limited.

[0005] To further enhance the thermal conductivity of composite materials, Chinese patent publication number CN 111500019 A discloses a highly thermally conductive, insulating epoxy resin material based on BN-Al2O3 modification and its preparation method. By surface-modifying the BN-Al2O3 and grafting epoxy groups onto it, the BN-Al2O3 can be incorporated into the epoxy resin's molecular chain. This enhances the compatibility and dispersibility of the nano-Al2O3 and BN with the epoxy resin, imparting excellent insulating and thermal conductivity to the epoxy resin. However, the introduction of excessive organic reagents during surface modification results in chemical contamination, making the process less environmentally friendly. Furthermore, the thermal conductivity of the modified composite material is only 0.542 to 0.815 W / mK. Summary of the Invention

[0006] The present invention aims to overcome the defect of low thermal conductivity of the thermal conductive filler-epoxy resin system dominated by boron nitride in the prior art due to imperfect thermal conductive network construction, and at the same time overcome the shortcomings of poor mechanical properties and heat resistance of traditional thermal conductive films. A high thermal conductive insulating resin composition, a high thermal conductive insulating film and a preparation method thereof are provided to overcome the above-mentioned defects.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A high thermal conductivity insulating resin composition comprises the following components in parts by weight: 40 to 80 parts of epoxy resin and 20 to 60 parts of thermal conductive filler; wherein the thermal conductive filler comprises a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and flaky hexagonal boron nitride.

[0009] The inventors of this application selected different thermally conductive fillers with different morphologies to construct a thermally conductive system. Tabular corundum has a spherical particle structure, cubic boron nitride has a nanosheet structure, cubic boron arsenide has a spherical particle structure, and hexagonal boron nitride has a scaly structure. By blending spherical particles with flakes, the flakes are oriented horizontally to create a horizontal heat conduction path. Spherical particles fill the gaps between the fillers, completing the horizontal heat conduction network and acting as a bridge to create a vertical heat conduction path. This results in a comprehensive thermally conductive system in both horizontal and vertical directions.

[0010] Furthermore, cubic boron nitride, as the most commonly used thermal conductive filler, has the advantages of high thermal conductivity and stable heat transfer, but it is relatively brittle and prone to cracking or breaking during use, affecting the stability and durability of the thermal conductive system. Therefore, compounding cubic boron nitride with plate-shaped corundum can solve this problem of cubic boron nitride. In addition, by pre-combining the plate-shaped corundum with cubic boron nitride, one of the flakes and one of the spherical particles are fused into one, reducing the interface impedance between different thermal conductive materials, and achieving uniform distribution of the plate-shaped corundum and cubic boron nitride in the thermal conductive system, achieving a three-dimensional dispersed distribution of the thermal conductive system, avoiding local concentration phenomena such as overlapping of flakes and adhesion of particles; at the same time, it helps to build a diversified thermal conductive system, which is beneficial to the dispersion and stability of thermal conductive materials.

[0011] In this way, the uniform distribution of plate-shaped corundum enables its high compressive strength, high toughness and high crack resistance to drive the uniform increase of the compressive and crack resistance of the entire heat conduction system, making it less likely to collapse in a certain place.

[0012] Furthermore, the ratio of thermally conductive filler to epoxy resin should be such that the filler is evenly coated by the epoxy resin. The addition of thermally conductive filler improves the thermal conductivity of the composition. However, excessive amounts of filler will prevent the epoxy resin from evenly coating the filler, resulting in an inhomogeneous composition. Therefore, maintaining a ratio of 40-80 parts epoxy resin to 20-60 parts thermally conductive filler yields a composition with excellent and uniform thermal conductivity.

[0013] In summary, by selecting a variety of thermally conductive fillers with different morphologies and fusing one of the flake-shaped particles with one of the spherical particles into one, a uniform thermally conductive system with thermally conductive pathways in both horizontal and vertical directions and diversified structures can be constructed, which greatly improves the thermal conductivity of the composition. At the same time, the mechanical properties of the prepared composition are significantly improved due to the presence of plate-shaped corundum.

[0014] Preferably, the average particle size of the plate-shaped corundum is 1-3 μm, the average particle size of the cubic boron nitride is 100-400 nm, the average particle size of the cubic boron arsenide is 100-300 nm, and the average particle size of the flaky hexagonal boron nitride is 5-15 μm.

[0015] Further preferably, the average particle size of the plate-like corundum is 1-3 μm, the average particle size of the cubic boron nitride is 200-400 nm, the average particle size of the cubic boron arsenide is 150-300 nm, and the average particle size of the flaky hexagonal boron nitride is 5-15 μm.

[0016] Further preferably, the average particle size of the plate-shaped corundum is 2 μm, the average particle size of the cubic boron nitride is 300-350 nm, the average particle size of the cubic boron arsenide is 200-300 nm, and the average particle size of the hexagonal boron nitride is 10-15 μm.

[0017] The scaly hexagonal boron nitride flakes, with a particle size close to the thickness of the cured film, penetrate the film and significantly improve the thermal conductivity of the thermally conductive film. The smaller cubic boron nitride and cubic boron arsenide particles, at their respective sizes, can fill the gaps in the system to the greatest extent possible, reducing the interfacial thermal resistance between the resin and the powder, thereby improving thermal conductivity.

[0018] Among them, the molecular particle sizes of cubic boron nitride and cubic boron arsenide are both nanometer-scale, while the molecular particle sizes of plate-like corundum and flaky hexagonal boron nitride are both micrometer-scale. Combining nanometer-scale and micrometer-scale particles can construct a multi-level three-dimensional structure. Nanometer-scale particles are beneficial to improving the interfacial activity and reactivity of the material, while micrometer-scale particles have a larger surface area. This multi-level structure is beneficial to improving the thermal conductivity coefficient of the thermal conductive system. In addition, after blending thermal conductive fillers of different particle sizes, their respective advantages can be brought into play. The large specific surface area and reactivity of nanometer-scale particles and the high mechanical strength of micrometer-scale particles can be utilized. The large specific surface area and reactivity help to improve the interaction between the thermal conductive system and the epoxy resin and increase the contact area with the epoxy resin, while the high mechanical strength can improve the structural stability of the thermal conductive system. The combination of the two synergistically enhances the overall thermal conductivity of the resin composition.

[0019] In addition, in order to meet the plate-shaped corundum particle size required for the film production of the present invention, it is necessary to purchase finished products on the market and perform fine processing to obtain small particles with an average particle size of 1 to 3 μm. The use of large particles will lead to difficulties in film formation and poor flatness of the obtained film.

[0020] Preferably, the composite material of plate-like corundum and cubic boron nitride is obtained by using plate-like corundum with a larger particle size as a core and cubic boron nitride with a smaller particle size as a shell.

[0021] Tabular corundum has stronger resistance to compression and cracking. The composite material made with it as the core has both high resistance to compression and cracking. The core will not break and cause the collapse of the entire core-shell structure, which can ensure further reinforcement of the thermal conductive system structure.

[0022] Preferably, the cubic boron nitride is modified from dopamine hydrochloride.

[0023] After the sheet-shaped hexagonal boron nitride is penetrated through the heat conduction system, the cubic boron nitride, as another sheet-shaped filler, has a larger specific surface area, and thus when being fused with the epoxy resin, the common problem between the inorganic filler and the organic matter, i.e. the poor compatibility problem, is prone to occur. After the dopamine hydrochloride is used to modify the cubic boron nitride, the nanometer polydopamine is generated on the surface of the cubic boron nitride, the B atoms and the N atoms of the cubic boron nitride alternately form a hexagonal ring grid structure, and the specific surface area of the cubic boron nitride nanosheet is very large, so it is easy to interact with the benzene ring structure of the polydopamine through the π-π bond conjugation and the van der Waals force, so that the polydopamine is firmly combined on the surface of the cubic boron nitride. The polydopamine molecule has good compatibility with the epoxy resin, and can help the cubic boron nitride to be fused with the epoxy resin to obtain a uniform composition.

[0024] Further, when the core-shell structure of the tabular corundum and the cubic boron nitride is formed, the compatibility of the cubic boron nitride and the epoxy resin is more important, and thus it is crucial to use the modification to enhance the fusion of the cubic boron nitride and the epoxy resin.

[0025] Preferably, the mass ratio between the cubic boron nitride and the tabular corundum in the tabular corundum and cubic boron nitride composite material is 1:(0.1-0.5).

[0026] Preferably, the mass ratio between the tabular corundum and cubic boron nitride composite material, the cubic boron arsenide and the sheet-shaped hexagonal boron nitride is (1:1:2)-(3:3:2).

[0027] Preferably, the high-thermal-conductivity insulating resin composition further comprises 1-4 parts of a curing agent.

[0028] The application also provides a preparation method of the high-thermal-conductivity insulating resin composition, which comprises the following steps:

[0029] S1, dispersing the cubic boron nitride in anhydrous ethanol, adding a dopamine hydrochloride solution under stirring, reacting at 50-70℃ for 12-24h, and then filtering after centrifugation to obtain modified cubic boron nitride;

[0030] S2, dispersing the modified cubic boron nitride in water, adding a tabular corundum dispersion under stirring, and then filtering after high-speed stirring to obtain a tabular corundum and cubic boron nitride composite material;

[0031] S3, uniformly stirring the epoxy resin, the tabular corundum and cubic boron nitride composite material, the cubic boron arsenide, the hexagonal boron nitride and heating, cooling to room temperature, adding a curing agent, uniformly stirring, grinding, vacuum filtering, uniformly stirring again, and then obtaining a film liquid, i.e. the high-thermal-conductivity insulating resin composition.

[0032] The inventors of this application modified cubic boron nitride and then combined it with plate-like corundum to create a preliminary premixed composite material. This premixed composite material was then simply mixed and heated with cubic boron arsenide, flake hexagonal boron nitride, and epoxy resin to produce a highly thermally conductive insulating resin composition. This entire solution requires minimal equipment, can be completed without specialized equipment, and is cost-effective, making it easily applicable and widely adopted.

[0033] Preferably, the stirring is performed under vacuum.

[0034] Vacuum mixing removes air bubbles and gas from the mixture during the mixing process, ensuring a more uniform mixture and reducing the impact of air pores and bubbles on the composition. It also improves the fluidity of the mixed components, resulting in a more uniform and stable composition.

[0035] More preferably, the vacuum degree of vacuum stirring is -95KPa.

[0036] Preferably, in step S3, the pore size of the filter used for filtration is 100 μm.

[0037] A filtration pore size that is too small will result in the resin component being unable to be filtered completely, so keeping it at 100μm can achieve the desired filtration effect, that is, the resin composition obtained by compounding the thermal conductive filler and the resin can be filtered smoothly, and the powder with a particularly large particle size (greater than 100μm) can be screened out in this process.

[0038] Preferably, in step S3, the heating temperature is 50-60°C.

[0039] More preferably, the heating temperature is 55°C.

[0040] The present invention also provides a high thermal conductivity insulating film obtained by thermally curing the high thermal conductivity insulating resin composition or the high thermal conductivity insulating resin composition prepared by the above method.

[0041] The high thermal conductivity insulating resin composition was evenly coated on a polytetrafluoroethylene plate and placed in a vacuum drying oven for curing to obtain a high thermal conductivity insulating film. The performance of the obtained high thermal conductivity insulating film was characterized and it was found that its thermal conductivity coefficient could reach 6.30W / mK and the thermal diffusion coefficient was 3.42m 2 / s, and has good insulation properties, which can meet the current actual production needs.

[0042] Therefore, the present invention has the following beneficial effects:

[0043] (1) The high thermal conductivity insulating resin composition proposed in the present invention utilizes flaky and spherical granular thermal conductive fillers of different particle sizes to construct a complete thermal conductive network. The designed epoxy resin-thermal conductive filler system has a high thermal conductivity coefficient and exhibits high thermal conductivity and good insulation properties.

[0044] (2) The present invention is designed to pre-compound plate-shaped corundum and cubic boron nitride, which can effectively reduce the interface impedance between different thermal conductive materials, realize the three-dimensional dispersed distribution of the thermal conductive system, and avoid local concentration phenomena such as overlapping of sheets and adhesion of particles; at the same time, it helps to construct a diversified thermal conductive system, which is beneficial to the dispersion and improvement of the stability of the thermal conductive material; the introduced plate-shaped corundum can improve the mechanical properties and heat resistance of the thermal conductive film.

[0045] (3) The present invention is designed to compound micron-scale and nano-scale thermal conductive fillers. Combining nano-scale and micron-scale particles can construct a multi-level three-dimensional structure. The combination of the two can synergistically enhance the overall thermal conductivity of the resin composition.

[0046] (4) The present invention prepares a high thermal conductivity insulating resin composition by simple mixing and heating. The entire solution has low dependence on equipment and is low in cost, and is easy to be widely promoted and applied.

[0047] (5) The high thermal conductivity insulating film proposed in the present invention is obtained by thermally curing a high thermal conductivity insulating resin composition, has good thermal conductivity and insulation properties, and can be widely used in the field of microelectronic integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a comparison diagram of the high thermal conductivity insulating film in a cracked state;

[0049] Figure 2 This is a comparison chart of the high thermal conductivity insulation film in a non-cracked state. DETAILED DESCRIPTION

[0050] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0051] [Example]

[0052] Example 1

[0053] In this embodiment, the average particle size of plate-shaped corundum is 2 μm, the average particle size of cubic boron nitride is 320 nm, the average particle size of cubic boron arsenide is 275 nm, and the average particle size of flaky hexagonal boron nitride is 12 μm.

[0054] S1. Disperse cubic boron nitride in anhydrous ethanol, add 2 g / L dopamine hydrochloride solution under stirring, react at 60° C. for 12 h, centrifuge and filter to obtain modified cubic boron nitride.

[0055] S2. Disperse 1 g of modified cubic boron nitride in water, add 250 mL of a 2 g / L plate-shaped corundum dispersion while stirring, and stir under a vacuum of -95 kPa at 2000 r / min for 6 h. Filter to obtain a composite material of plate-shaped corundum and cubic boron nitride. The above ratio can be scaled up or down to obtain the desired amount of composite material.

[0056] S3. Stir 60g of bisphenol A epoxy resin, 10g of a composite material of plate-like corundum and cubic boron nitride, 10g of cubic boron arsenide, and 20g of hexagonal boron nitride under vacuum at 55°C and -95KPa for 1h. After cooling to room temperature, add 1g of dicyandiamide curing agent, stir for 20min, grind, filter, and stir for another 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0057] S4. Evenly apply the high thermal conductive insulating resin composition onto a polytetrafluoroethylene plate, place the plate in a vacuum drying oven at 80° C. and dry for 6 hours to solidify it into a thermal conductive insulating film.

[0058] Example 2

[0059] This embodiment is basically the same as embodiment 1, except that:

[0060] S2. Disperse 1 g of modified cubic boron nitride in water, add 150 mL of a 2 g / L plate-shaped corundum dispersion while stirring, and stir under a vacuum of -95 kPa at 2000 r / min for 6 h. Filter to obtain a composite material of plate-shaped corundum and cubic boron nitride. Scale up or down the above ratio to obtain the desired amount of composite material.

[0061] Example 3

[0062] This example is essentially the same as Example 1, except that: S2: 1 g of modified cubic boron nitride was dispersed in water, 50 mL of a 2 g / L plate-shaped corundum dispersion was added with stirring, and the mixture was stirred at 2000 rpm under a vacuum of -95 kPa for 6 h. The plate-shaped corundum and cubic boron nitride composite material was filtered. The above ratio was scaled up or down to produce the desired amount of composite material.

[0063] Example 4

[0064] This embodiment is basically the same as embodiment 1, except that:

[0065] S3. Stir 60g of bisphenol A epoxy resin, 6g of a composite material of plate-like corundum and cubic boron nitride, 9g of cubic boron arsenide, and 25g of flaky hexagonal boron nitride in a vacuum at 55°C and -95KPa for 1h. After cooling to room temperature, add 1g of dicyandiamide curing agent, stir for 20min, grind, filter, and stir for another 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0066] Example 5

[0067] This embodiment is basically the same as embodiment 1, except that:

[0068] S3. Stir 60g of bisphenol A epoxy resin, 15g of a composite material of plate-like corundum and cubic boron nitride, 15g of cubic boron arsenide, and 10g of flaky hexagonal boron nitride at 55°C and -95KPa in a vacuum atmosphere for 1h. After cooling to room temperature, add 1g of dicyandiamide curing agent, stir for 20min, grind, filter, and stir for another 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0069] Example 6

[0070] This embodiment is basically the same as embodiment 1, except that:

[0071] S3. Stir 80g of bisphenol A epoxy resin, 5g of a composite material of plate-like corundum and cubic boron nitride, 5g of cubic boron arsenide, and 10g of flaky hexagonal boron nitride at 55°C and -95KPa in a vacuum for 1h. After cooling to room temperature, add 1g of dicyandiamide curing agent, stir for 20min, grind, filter, and stir for another 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0072] Example 7

[0073] This embodiment is basically the same as embodiment 1, except that:

[0074] S3. Stir 70g of bisphenol A epoxy resin, 7.5g of a composite material of plate-like corundum and cubic boron nitride, 7.5g of cubic boron arsenide, and 15g of flaky hexagonal boron nitride at 55°C and -95KPa in a vacuum atmosphere for 1h. After cooling to room temperature, add 1g of dicyandiamide curing agent, stir for 20min, grind, filter, and stir for another 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0075] Example 8

[0076] This embodiment is basically the same as embodiment 1, except that:

[0077] S3. 50g of bisphenol A epoxy resin, 12.5g of a composite material of plate-like corundum and cubic boron nitride, 12.5g of cubic boron arsenide, and 25g of flaky hexagonal boron nitride were stirred at 55°C and -95KPa under vacuum for 1h. After cooling to room temperature, 1g of dicyandiamide curing agent was added. After stirring for 20min, the mixture was ground and filtered, and then stirred for 15min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0078] Example 9

[0079] This example is substantially the same as Example 1, except that:

[0080] S3, 40 g of bisphenol a epoxy resin, 15 g of a composite material of tabular corundum and cubic boron nitride, 15 g of cubic boron arsenide, 30 g of flaky hexagonal boron nitride were stirred at 55°C under -95 KPa vacuum for 1 h, 1 g of dicyandiamide curing agent was added after cooling to room temperature, and the mixture was stirred for 20 min, ground, suction filtered, and then stirred for 15 min to obtain a film liquid, i.e., a high-thermal-conductivity insulating resin composition.

[0081] Example 10

[0082] This example is substantially the same as Example 1, except that:

[0083] In this example, the average particle diameter of the tabular corundum was 1 μm, the average particle diameter of the cubic boron nitride was 360 nm, the average particle diameter of the cubic boron arsenide was 120 nm, and the average particle diameter of the flaky hexagonal boron nitride was 8 μm.

[0084] Example 11

[0085] This example is substantially the same as Example 1, except that:

[0086] In this example, the average particle diameter of the tabular corundum was 3 μm, the average particle diameter of the cubic boron nitride was 320 nm, the average particle diameter of the cubic boron arsenide was 180 nm, and the average particle diameter of the flaky hexagonal boron nitride was 15 μm.

[0087] Comparative Example 1

[0088] This comparative example is substantially the same as Example 1, except that:

[0089] S3, 60 g of bisphenol a epoxy resin, 40 g of a composite material of tabular corundum and cubic boron nitride were stirred at 55°C under -95 KPa vacuum for 1 h, 1 g of dicyandiamide curing agent was added after cooling to room temperature, and the mixture was stirred for 20 min, ground, suction filtered, and then stirred for 15 min to obtain a film liquid, i.e., a high-thermal-conductivity insulating resin composition.

[0090] Comparative Example 2

[0091] This comparative example is substantially the same as Example 1, except that: S3, 60 g of bisphenol a epoxy resin, 10 g of a composite material of tabular corundum and cubic boron nitride, 30 g of cubic boron arsenide were stirred at 55°C under -95 KPa vacuum for 1 h, 1 g of dicyandiamide curing agent was added after cooling to room temperature, and the mixture was stirred for 20 min, ground, suction filtered, and then stirred for 15 min to obtain a film liquid, i.e., a high-thermal-conductivity insulating resin composition.

[0092] Comparative Example 3

[0093] This comparative example is basically the same as Example 1, except that:

[0094] S3. Stir 60 g of bisphenol A epoxy resin, 10 g of a composite material of plate-like corundum and cubic boron nitride, and 30 g of flaky hexagonal boron nitride at 55°C and -95 KPa in a vacuum atmosphere for 1 h. After cooling to room temperature, add 1 g of dicyandiamide curing agent, stir for 20 min, grind, filter, and stir for another 15 min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0095] Comparative Example 4

[0096] This comparative example is basically the same as Example 1, except that:

[0097] Cancel S2 compounding; S3, 60 g of bisphenol A epoxy resin, 6.7 g of plate-shaped corundum, 3.3 g of cubic boron nitride, 10 g of cubic boron arsenide, and 20 g of flaky hexagonal boron nitride were stirred at 55°C and -95 KPa under vacuum for 1 h. After cooling to room temperature, 1 g of dicyandiamide curing agent was added. After stirring for 20 min, the mixture was ground and filtered, and then stirred for another 15 min to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

[0098] Comparative Example 5

[0099] This comparative example is basically the same as Example 1, except that the modification step of S1 is omitted and compounding is performed directly.

[0100]

Performance test

[0101] 1. The influence of different proportions of cubic boron nitride and tabular corundum

[0102] In order to verify the effect of the addition ratio of plate-shaped corundum nanocrystals on the thermal stability and compressive strength of the formed high thermal conductivity insulating film, the high thermal conductivity insulating films prepared in Examples 1 to 3 were applied to a double-sided copper-clad laminate vacuum hot pressing experiment (the upper and lower copper foils were 0.3 mm and 0.8 mm oxygen-free copper, respectively, and the hot pressing time was uniformly 1 hour). The copper-clad carrier substrate after hot pressing was scanned with an ultrasonic scanner to determine whether the high thermal conductivity insulating film in the middle was cracked. The hot pressing results are as follows:

[0103] Table 1 Hot pressing results of Example 1

[0104]

[0105] Table 2 Hot pressing results of Example 2

[0106]

[0107]

[0108] Table 3 Hot pressing results of Example 3

[0109]

[0110] The results of Tables 1 to 3 show that Figures 1-2 The cracking effect of the membrane is clearly visible. The uncracked membrane is smooth and flat without gaps. However, the membrane is prone to severe cracking under high temperature and high pressure, which shortens the membrane's service life. When the mass ratio of cubic boron nitride to plate-shaped corundum is 1:0.5, the high thermal conductivity insulating film exhibits better thermal stability and compressive resistance, ensuring that the membrane does not crack at 190°C and 2.5MPa.

[0111] 2. The influence of different ratios of thermal conductive fillers

[0112] After determining the optimal ratio of cubic boron nitride and tabular corundum, we investigated the effect of the thermally conductive filler ratio on the high thermal conductivity insulating film. The films obtained in Examples 1, 4, and 5 were tested for thermal conductivity, thermal diffusivity, and insulation properties. The results are shown in Table 4.

[0113] Table 4 Test results of films with different thermal conductive filler ratios

[0114]

[0115] From the data in the table, we can see that as the total proportion of plate-like corundum and cubic boron nitride in the system increases, the thermal conductivity and thermal diffusivity of the film gradually decrease. This is related to the fact that the thermal conductivity of plate-like corundum itself is not as good as that of boron nitride. Its addition is mainly to improve the mechanical properties and heat resistance of the film.

[0116] 3. The influence of different ratios of filler and epoxy resin

[0117] After determining the optimal ratio of thermally conductive filler, we then explored the effects of different filler-to-resin ratios on the high thermal conductivity insulating film. The films obtained in Examples 1 and 6-9 were tested for thermal conductivity, thermal diffusivity, and insulation properties. The results are shown in Table 5.

[0118] Table 5 Test results of membranes with different filler ratios

[0119]

[0120]

[0121] The data in the table show that increasing the filler dosage significantly improves the film's various properties. When the filler-to-resin ratio is greater than 2:3, the film's various properties reach a high level. As the filler dosage continues to increase, film performance continues to improve.

[0122] 4. Impact of thermal network construction

[0123] The films obtained in Example 1 and Comparative Examples 1 to 5 were tested for thermal conductivity, thermal diffusivity and insulation properties. The results are shown in Table 6.

[0124] Table 6 Test results of membranes with different thermal conductivity networks

[0125]

[0126] From the data in the table, it can be seen that comparative examples 1 to 3 lack cubic boron arsenide and / or flake hexagonal boron nitride. Without flake hexagonal boron nitride, the film lacks the most critical thermal conductive support material, and its performance is greatly reduced, especially the thermal conductivity.

[0127] Comparing the data from Example 1 with Comparative Example 4 reveals that when plate-shaped corundum and cubic boron nitride are added directly to the bisphenol A epoxy resin without pre-compounding, performance declines, with both thermal conductivity and thermal diffusivity decreasing compared to pre-mixed addition. This is due to the overlapping of flakes and adhesion of particles during the mixing process, which leads to localized concentration and reduced dispersion of the thermally conductive filler. Furthermore, the uneven distribution and adhesion of filler at various locations prevents optimal performance of different fillers, preventing optimal synergy between fillers of different morphologies and particle sizes, leading to performance degradation.

[0128] In summary, the premixing of tabular corundum and cubic boron nitride, as well as the intermixing of different fillers with varying particle sizes, is essential for achieving a complete thermal network. The resulting high-thermal-conductivity insulating film exhibits a highly complete thermal network, achieving both high thermal conductivity, high insulation, and high stability.

Claims

1. A high thermal conductive insulating resin composition, characterized in that: The invention comprises the following components in parts by weight: 40-80 parts of epoxy resin, 20-60 parts of thermally conductive filler, and 1-4 parts of curing agent; wherein the thermally conductive filler comprises a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and flaky hexagonal boron nitride; the cubic boron nitride is modified with dopamine hydrochloride; The average particle size of the plate-like corundum is 1-3 μm, the average particle size of the cubic boron nitride is 100-400 nm, the average particle size of the cubic boron arsenide is 100-300 nm, and the average particle size of the flaky hexagonal boron nitride is 5-15 μm; The mass ratio of cubic boron nitride to plate-like corundum in the composite material of plate-like corundum and cubic boron nitride is 1:(0.1-0.5); the mass ratio of the composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and flaky hexagonal boron nitride is (1:1:2)-(3:3:2).

2. The highly thermally conductive insulating resin composition according to claim 1, wherein The composite material of plate-shaped corundum and cubic boron nitride is obtained by combining plate-shaped corundum with a larger particle size as a core and cubic boron nitride with a smaller particle size as a shell.

3. The method for preparing the highly thermally conductive insulating resin composition according to any one of claims 1 to 2, wherein: The following steps are involved: S1. Dispersing cubic boron nitride in anhydrous ethanol, adding dopamine hydrochloride solution under stirring, reacting at 50-70°C for 12-24 hours, centrifuging and filtering to obtain modified cubic boron nitride; S2. Dispersing the modified cubic boron nitride in water, adding the plate-like corundum dispersion under stirring, stirring at high speed, and filtering to obtain a composite material of plate-like corundum and cubic boron nitride; S3. Heat and stir epoxy resin, a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and flaky hexagonal boron nitride until uniform. After cooling to room temperature, add a curing agent, stir until uniform, grind, filter, and stir again to obtain a membrane liquid, i.e., a high thermal conductive insulating resin composition.

4. The method according to claim 3, characterized in that In step S3, the pore size of the filter used for filtration is 100 μm.

5. A high thermal conductivity insulating film, characterized in that: The invention is obtained by thermally curing the high thermal conductive insulating resin composition according to any one of claims 1 to 2 or the high thermal conductive insulating resin composition prepared by the method according to any one of claims 3 to 4.

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