Insulating heat-conducting glue, superconducting aluminum-based copper-clad plate and preparation method of insulating heat-conducting glue

Abstract

The invention relates to the technical field of heat-conducting glue and copper-clad plates, in particular to insulating heat-conducting glue, a superconducting aluminum-based copper-clad plate and a preparation method of the insulating heat-conducting glue. The insulating heat-conducting adhesive comprises the following raw material components in parts by weight: 8-10 parts of modified epoxy resin, 2-3 parts of nitrile rubber, 70-75 parts of filler, 5-6 parts of a curing agent, 0.1-0.3 part of an antioxidant and 10-15 parts of an organic solvent, wherein the molecular weight of the modified epoxy resin is 28000-32000. The insulating heat-conducting adhesive disclosed by the invention is good in flexibility, compactness and heat resistance and high in heat conductivity coefficient, and has excellent thermal property, electrical property and mechanical property and good reliability when being used in a superconducting copper-clad plate.

Description

Technical Field

[0001] The present invention relates to the technical field of thermally conductive adhesives and copper-clad laminates, and in particular to an insulating thermally conductive adhesive, a superconducting aluminum-based copper-clad laminate, and a preparation method of the insulating thermally conductive adhesive. Background Art

[0002] Aluminum-based copper-clad laminates (ACLs) are a type of sheet material made from electronic fiberglass cloth or other reinforcing materials impregnated with resin or a single resin as an insulating adhesive layer, coated on one or both sides with copper foil, and then hot-pressed. These materials are known as copper-clad aluminum laminates. As the substrate material used in printed circuit board (PCB) manufacturing, ACLs primarily provide interconnection, insulation, and support for the PCB, significantly impacting signal transmission speed, energy loss, and characteristic impedance within the circuit. The performance, quality, processability, manufacturing level, manufacturing cost, and long-term reliability and stability of a PCB depend heavily on the ACLs. Furthermore, as a core heat dissipation component, their thermal conductivity and structural stability directly determine the reliability and service life of electronic equipment.

[0003] Thermally conductive adhesives, as thermal interface materials for copper-clad laminates (CCLs), play a key role in filling the gap between devices and heat sinks and improving thermal conductivity. Traditional epoxy-based thermally conductive adhesives are brittle due to their high crosslink density and are prone to cracking when subjected to thermal stress or mechanical impact. For example, the insulating layer of conventional aluminum-based CCLs utilizes a prepreg reinforced with glass fiber cloth. Its rigid structure is susceptible to delamination or fracture due to stress concentration during three-dimensional processing. Furthermore, existing technologies often utilize fillers of a single particle size, which easily agglomerate to form pores and have poor compatibility with the matrix, resulting in discontinuous thermal conduction paths and low thermal conductivity. Furthermore, the interfacial bonding between the filler and the matrix is weak, leading to severe phonon scattering, further reducing the effective thermal conductivity. Furthermore, existing technologies generally utilize a single curing system, resulting in poor temperature resistance and prone to softening, failure, and delamination under high temperature and high pressure. This further accelerates the thermal decomposition of the CCL colloid, directly impacting the reliability and service life of electronic equipment. Therefore, the development of a new insulating thermally conductive adhesive is expected to address these issues. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an insulating thermally conductive adhesive, a superconducting aluminum-based copper-clad laminate and a preparation method of the insulating thermally conductive adhesive. The insulating thermally conductive adhesive prepared by the present invention has good flexibility, density, heat resistance, high thermal conductivity, is suitable for superconducting copper-clad laminates, and has excellent overall performance.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: One aspect of the present invention provides an insulating thermally conductive adhesive comprising the following raw materials, measured by weight: 8-10 parts of a modified epoxy resin, 2-3 parts of a nitrile rubber, 70-75 parts of a filler, 5-6 parts of a curing agent, 0.1-0.3 parts of an antioxidant, and 10-15 parts of an organic solvent. The modified epoxy resin has a molecular weight of 28,000-32,000. The present invention utilizes a high-molecular-weight epoxy resin as the primary resin raw material, which not only improves the material's heat resistance, chemical resistance, and strength, but also enhances its bonding strength with copper foil and aluminum sheet, improving the product's flexibility and facilitating product processing, preventing product abnormalities such as chipping and cracking during processing. Furthermore, the use of a high-molecular-weight modified epoxy resin prevents cracking and other issues even when the filler ratio is increased, resulting in a high thermal conductivity.

[0006] According to a further technical solution, the preparation method of the modified epoxy resin is as follows: bisphenol A epoxy resin and bisphenol A are subjected to a chain extension reaction under catalyst conditions, and the molecular weight is monitored in real time by GPC. When the molecular weight reaches the desired molecular weight, the reaction is terminated, and then maleic anhydride-terminated polyethersulfone is added and mixed evenly, an initiator is added, and the modified epoxy resin is obtained after the reaction is completed.

[0007] Furthermore, the amount of bisphenol A used is 0.8-1.2 times the molar amount of the bisphenol A epoxy resin; the catalyst is triethanolamine or tetrabutylammonium bromide, and the amount used is 0.3-0.5% of the total mass of the bisphenol A epoxy resin; the temperature of the chain extension reaction is 120-140°C, and the time is 2-4 hours; the amount of the maleic anhydride-terminated polyethersulfone used is 0.3-0.5 times the molar amount of the bisphenol A epoxy resin; the initiator is benzoyl peroxide, and the amount used is 0.5-1% of the total mass of the bisphenol A epoxy resin; the reaction temperature is 80-120°C, and the time is 3-5 hours.

[0008] Specifically, bisphenol A epoxy resin and bisphenol A are mixed in a molar ratio of 1:0.8-1.2, 0.3-0.5% of a catalyst triethanolamine or tetrabutylammonium bromide is added, a chain extension reaction is carried out at 120-140° C. for 2-4 hours, and the molecular weight is monitored in real time by GPC. When the molecular weight reaches about 25,000, 0.5-0.8% of mercaptopropionic acid is added to terminate the reaction, and then 0.3-0.5 times the molar amount of bisphenol A epoxy resin and maleic anhydride-terminated polyethersulfone are added and mixed evenly, 0.5-1% of benzoyl peroxide is added, and the mixture is reacted at 80-120° C. for 3-5 hours to obtain the modified epoxy resin.

[0009] The present invention introduces repeating units into the main chain by reacting epoxy groups with the hydroxyl / epoxy groups of the chain extender bisphenol A through a ring-opening addition reaction, gradually increasing the molecular weight. Then, through free radical copolymerization / ring-opening grafting, the flexible chain segment (maleic anhydride-terminated polyethersulfone) is embedded into the epoxy main chain, reducing the crosslinking density and enhancing the flexibility of the epoxy resin.

[0010] According to a further technical solution, the filler is a composition with a mass ratio of magnesium oxide to aluminum oxide of 7-8:8-9. The filler in this technical solution adopts a variety of composite materials, especially magnesium oxide, which can greatly improve the thermal conductivity of the material.

[0011] Preferably, the magnesium oxide has a particle size D50 of 5 μm; the aluminum oxide is a composite of aluminum oxides of varying particle sizes and shapes, with spherical aluminum oxide with a D50 of 5 μm accounting for 65-80%, spherical aluminum oxide with a D50 of 2 μm accounting for 5-10%, and α-alumina with a D50 of 5 μm accounting for 15-25%. Magnesium oxide is an insulating material with high thermal conductivity. Its proper addition to fillers can significantly improve the thermal conductivity of the colloid. By utilizing different fillers of varying particle sizes and shapes, the present invention achieves a high packing density and maximizes the filler content, significantly improving not only thermal conductivity but also rigidity and creep resistance, resulting in excellent mechanical properties and low cost.

[0012] According to a further technical solution, the curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 1.8-2.5:1. After diaminodiphenyl sulfone (DDS) cures the epoxy, the curing system has high heat resistance, yellowing resistance and chemical stability, and can maintain stability in a high temperature environment, so that the glass transition temperature Tg point of the material is higher, but the brittleness of the cured product is relatively large. Dicyandiamide (Dicy) as a curing agent can make the epoxy resin undergo a cross-linking reaction at a relatively low curing temperature. After curing the epoxy, it can improve the solvent resistance and chemical corrosion resistance of the material, improve the light resistance of the material, and make the material have better weather resistance and UV resistance. The present invention adopts a dual curing agent combined technology, which can effectively reduce the temperature of the cross-linking reaction, and the resulting material has better high temperature stability, chemical resistance, weather resistance and high pressure resistance.

[0013] According to a further technical solution, the antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:1-3; the organic solvent is dimethylformamide. V-992B epoxy resin is designed for high-temperature systems, inhibiting molecular oxidative degradation at high temperatures, reducing the risk of yellowing. UV-1050, also known as an anti-yellowing additive, has strong absorption capacity across the entire UV spectrum and is resistant to high-temperature oxidation. This technical solution maximizes the material's resistance to yellowing within temperatures up to 200°C by combining these two.

[0014] Another aspect of the present invention provides a method for preparing the above-mentioned insulating thermally conductive adhesive, comprising the following steps: (1) Pour half of the organic solvent into a stainless steel barrel according to the ratio, then pour in the curing agent and start stirring until the solution is completely transparent and clear; (2) Pour the other half of the organic solvent into the mixing tank according to the ratio, add the modified epoxy resin and nitrile rubber in turn, cover the tank, and start stirring until dissolved; (3) Pour the clarified liquid from step (1) into the glue mixing tank from step (2), cover the tank, and start stirring for more than 1 hour until glue is formed; (4) Pour the glue obtained in step (3) into the disperser, adjust the speed, add the filler once while stirring, and then start high-speed shear stirring and stir for more than 1.5 hours; (5) The slurry obtained in step (4) is introduced into a grinder for grinding, wherein the mixing tank pipe is connected to the grinder feed port, the grinder feed port is connected to a 10000GS magnetic filter, the grinder outlet is filtered with a 150 mesh polyester mesh, the receiving barrel is covered with a layer of 150 mesh filter mesh, and after filtering, the material is introduced into a storage tank for standby use; (6) Seal the glue ground in step (5), stir at high speed for 4-5 hours, then reduce the speed and stir for 8-10 hours. During the stirring process, place a 10000GS magnetic rod in the barrel; the magnetic rod can absorb metal impurities in the material and improve the stability of the material; (7) The glue that has fully reacted in step (6) is vacuumized to obtain the product.

[0015] Furthermore, in step (3), the stirring speed is 500 rpm; in step (4), the speed is adjusted to 200-300 rpm, the high-speed shear speed is 700-800 rpm, and the temperature is ≤70°C; in step (5), the grinding machine speed is 800-1200 r / min, grinding is performed 2-3 times, and the grinding machine cavity temperature is 60-80°C.

[0016] Another aspect of the present invention provides an insulating thermally conductive adhesive film, wherein the insulating thermally conductive adhesive obtained above is supplied to a coating head glue tank, and a coating device is used to apply the glue to the release film with a scraper using a release film as a carrier. The thickness of the scraped glue is adjusted by the gap of the scraper to adjust the thickness to 30 μm. The insulating thermally conductive adhesive is baked in an oven from low temperature to high temperature to a semi-cured film state, and then cut into sheets.

[0017] Another aspect of the present invention provides a superconducting aluminum-based copper-clad laminate comprising a cured insulating thermally conductive adhesive film having a thickness of 30 μm. The superconducting aluminum-based copper-clad laminate is obtained by stacking two layers of the insulating thermally conductive adhesive film and laminating them with copper foil and aluminum plate.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses modified high molecular weight epoxy resin as the main resin, which has good flexibility and can improve the material's ability to resist elastic deformation and cracking; the filler is a variety of composite fillers with different particle sizes and shapes, and the materials are stacked and embedded with each other to maximize the filling amount, high packing density, and good compactness, which can improve the material's thermal conductivity, high pressure resistance and mechanical properties; the use of dual curing agents fully utilizes the advantages of both, improving the material's high temperature stability, chemical resistance, weather resistance and high pressure resistance.

[0019] The present invention comprises multiple steps of mixing and stirring. During the preparation process, a magnetic rod is used to remove metal impurities in the material. Multiple grinding is performed to completely disperse the filler in the epoxy resin to prevent agglomeration and sedimentation. Air bubbles are eliminated by vacuuming. The obtained insulating thermally conductive adhesive has good dispersibility, flexibility, and density, and a high thermal conductivity coefficient. It is suitable for making insulating thermally conductive adhesive films and copper-clad laminates, has good thermal and electrical properties, and excellent mechanical properties, and can meet the material performance requirements of superconducting aluminum-based copper-clad laminates in printed circuit boards. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The raw materials used in the following examples and comparative examples of the present invention are as follows: Bisphenol A epoxy resin (E-51, supplier: Dow Chemical); nitrile rubber (XL2740, supplier: Hengshui Enrui Rubber & Plastic); bisphenol A (BPA, supplier: Dow Chemical); mercaptopropionic acid (supplier: Dow Chemical); benzoyl peroxide (BPO, supplier: Arkema); maleic anhydride-terminated polyethersulfone (PES-MA, supplier: Solvay); magnesium oxide (supplier: China Magnesium Industry); aluminum oxide (supplier: Aluminum Corporation of China); diaminodiphenyl sulfone (DDS, supplier: Suzhou Yunfeng); dicyandiamide (Dicy, supplier: Merck); dimethylformamide (supplier: Merck); V-992B (supplier: Gaide Chemical); UV-1050 (supplier: Nanjing Jingtianwei Chemical).

[0022] Unless otherwise specified, the methods are conventional methods, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0023] Example 1 Preparation method of modified epoxy resin: bisphenol A epoxy resin and bisphenol A are mixed in a molar ratio of 1:0.8, 0.3% of a catalyst triethanolamine or tetrabutylammonium bromide is added, and a chain extension reaction is carried out at 140°C for 4 hours. The molecular weight is monitored in real time by GPC. When the molecular weight reaches about 25,000, 0.5% of mercaptopropionic acid is added to terminate the reaction, and then 0.3 times the molar amount of bisphenol A epoxy resin and maleic anhydride-terminated polyethersulfone are added and mixed evenly. 0.5% of benzoyl peroxide is added, and the mixture is reacted at 80°C for 3 hours to obtain a modified epoxy resin, and its molecular weight is detected to be 28,500.

[0024] Example 2 Preparation method of modified epoxy resin: bisphenol A epoxy resin and bisphenol A are mixed in a molar ratio of 1:1, 0.4% of a catalyst triethanolamine or tetrabutylammonium bromide is added, and a chain extension reaction is carried out at 130°C for 3 hours. The molecular weight is monitored in real time by GPC. When the molecular weight reaches about 25,000, 0.6% of mercaptopropionic acid is added to terminate the reaction. Then, 0.4 times the molar amount of bisphenol A epoxy resin is added with maleic anhydride-terminated polyethersulfone, mixed evenly, 0.7% of benzoyl peroxide is added, and the mixture is reacted at 100°C for 4 hours to obtain a modified epoxy resin. The molecular weight thereof is detected to be 29,500.

[0025] Example 3 Preparation method of modified epoxy resin: bisphenol A epoxy resin and bisphenol A are mixed in a molar ratio of 1:1.2, 0.5% of a catalyst triethanolamine or tetrabutylammonium bromide is added, and a chain extension reaction is carried out at 120°C for 3 hours. The molecular weight is monitored in real time by GPC. When the molecular weight reaches about 25,000, 0.8% of mercaptopropionic acid is added to terminate the reaction, and then 0.5 times the molar amount of bisphenol A epoxy resin and maleic anhydride-terminated polyethersulfone are added and mixed evenly. 1% benzoyl peroxide is added and the mixture is reacted at 120°C for 5 hours to obtain a modified epoxy resin, and its molecular weight is detected to be 31,000.

[0026] Example 4 An insulating thermally conductive adhesive comprises the following raw material components, calculated by weight: 8 parts of the modified epoxy resin obtained in Example 1, 2 parts of nitrile rubber, 70 parts of filler, 5 parts of curing agent, 0.1 part of antioxidant, and 10 parts of dimethylformamide, wherein: The filler is a composition of magnesium oxide and aluminum oxide in a mass ratio of 7:8, and the particle size D50 of the magnesium oxide is 5 μm; the aluminum oxide is 65% spherical aluminum oxide with a D50 of 5 μm, 10% spherical aluminum oxide with a D50 of 2 μm, and 25% α-alumina with a D50 of 5 μm; the curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 1.8:1; the antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:1.

[0027] The preparation method comprises the following steps: (1) Pour half of the organic solvent into a stainless steel barrel according to the ratio, then pour in the curing agent, start stirring (300 rpm) until the solution is completely transparent and clear; (2) Pour the other half of the organic solvent into the mixing tank according to the ratio, add the modified epoxy resin and nitrile rubber in sequence, cover the tank, and start stirring (300 rpm) until dissolved; (3) Pour the clarified liquid from step (1) into the glue mixing tank from step (2), cover the tank, and start stirring (500 rpm) for more than 1 hour until glue is formed; (4) Pour the glue obtained in step (3) into the disperser, adjust the speed, add the filler at a time while stirring (300 rpm), and then start high-speed shear stirring (700 rpm, temperature below 70°C) and stir for more than 1.5 hours; (5) The slurry obtained in step (4) is introduced into a grinder for grinding (800-1200 r / min), wherein the mixing tank pipe is connected to the grinder feed port, the grinder feed port is connected to a 10000GS magnetic filter, the grinder outlet is filtered with a 150 mesh polyester mesh, the receiving barrel is covered with a layer of 150 mesh filter mesh, and after filtering, the material is introduced into a storage tank for standby use and ground twice. The grinder is filled with zirconia beads with a particle size of 1.6 mm; (6) Seal the glue ground in step (5), stir at high speed (600 rpm) for 4-5 hours, then reduce the speed (200 rpm) and stir for 8-10 hours. During the stirring process, place a 10000GS magnetic rod in the barrel to remove metal impurities in the glue; (7) The glue that has fully reacted in step (6) is vacuumized to obtain the product.

[0028] Example 5 An insulating thermally conductive adhesive comprises the following raw material components, calculated by weight: 9 parts of the modified epoxy resin obtained in Example 2, 2.5 parts of nitrile rubber, 72 parts of filler, 5.5 parts of curing agent, 0.2 parts of antioxidant, and 12 parts of dimethylformamide, wherein: The filler is a composition of magnesium oxide and aluminum oxide in a mass ratio of 7:9, with the magnesium oxide having a particle size D50 of 5 μm. The aluminum oxide comprises 70% spherical aluminum oxide with a D50 of 5 μm, 8% spherical aluminum oxide with a D50 of 2 μm, and 22% α-alumina with a D50 of 5 μm. The curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 2:1. The antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:2. The preparation method is the same as in Example 4.

[0029] Example 6 An insulating thermally conductive adhesive comprises the following raw material components, calculated by weight: 10 parts of the modified epoxy resin obtained in Example 3, 3 parts of nitrile rubber, 75 parts of filler, 6 parts of curing agent, 0.3 parts of antioxidant, and 15 parts of dimethylformamide, wherein: The filler is a composition of magnesium oxide and aluminum oxide in a mass ratio of 8:9, with the magnesium oxide having a particle size D50 of 5 μm. The aluminum oxide comprises 80% spherical aluminum oxide with a D50 of 5 μm, 5% spherical aluminum oxide with a D50 of 2 μm, and 15% α-alumina with a D50 of 5 μm. The curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 2.5:1. The antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:3. The preparation method is the same as in Example 4.

[0030] Comparative Example 1 Preparation method of modified epoxy resin: bisphenol A epoxy resin and bisphenol A are mixed in a molar ratio of 1:1.2, 0.3% of a catalyst triethanolamine or tetrabutylammonium bromide is added, and a chain extension reaction is carried out at 140°C for 4 hours. The molecular weight is monitored in real time by GPC. When the molecular weight reaches about 28,000, 0.5% of mercaptopropionic acid is added to terminate the reaction, thereby obtaining a modified epoxy resin, the molecular weight of which is detected to be 28,400.

[0031] Comparative Example 2 An insulating thermally conductive adhesive, which differs from Example 4 in that the epoxy resin used is bisphenol A epoxy resin.

[0032] Comparative Example 3 An insulating thermally conductive adhesive, which differs from Example 4 in that the modified epoxy resin used is obtained by the method of Comparative Example 1.

[0033] Comparative Example 4 An insulating thermally conductive adhesive, which differs from Example 4 in that the filler used does not contain magnesium oxide.

[0034] Comparative Example 5 An insulating thermally conductive adhesive, which differs from Example 4 in that the filler used is a composition of magnesium oxide and α-aluminum oxide.

[0035] Comparative Example 6 An insulating thermally conductive adhesive, which differs from Example 4 in that the curing agent used is DDS.

[0036] Comparative Example 7 An insulating thermally conductive adhesive, which differs from Example 4 in that the curing agent used is Dicy.

[0037] The insulating thermally conductive adhesives prepared in Examples 4-6 and Comparative Examples 2-7 were first prepared into insulating thermally conductive adhesive films according to the following method: The insulating thermally conductive adhesive was supplied to a coating head tank. Using a coating device, the adhesive was applied to the release film using a scraper. The thickness of the applied adhesive was adjusted by the scraper gap to a thickness of 30 μm. The insulating thermally conductive adhesive was then oven-baked from low to high temperatures until it reached a semi-cured film state. The films were then cut into sheets, and the mechanical properties of the films were tested. The two layers of insulating thermally conductive adhesive films were then laminated with copper foil and aluminum plate at 180°C and 500 PSI to produce superconducting aluminum-based copper-clad laminates. The relevant properties were tested, as shown in Tables 1 and 2.

[0038] Table 1 Performance test results of samples of Examples 4-6

[0039] Table 2 Performance test results of samples of Comparative Examples 2-7

[0040] The test results in Tables 1 and 2 demonstrate that the insulating and thermally conductive adhesive film prepared using the formulation and preparation method of the present invention exhibits excellent mechanical properties and aging resistance. When applied to copper-clad laminates, it exhibits excellent overall performance, particularly high thermal conductivity, and good heat and pressure resistance. However, in Comparative Example 2, due to the unmodified epoxy resin, the insulating and thermally conductive adhesive film exhibits poor mechanical properties, which in turn impacts other properties to some extent. In Comparative Example 3, due to the lack of a flexible segment during epoxy resin modification, its mechanical properties are slightly inferior. In Comparative Example 4, while magnesium oxide is omitted as a filler, mechanical properties are minimally impacted, but thermal conductivity is excessively low. In Comparative Example 5, the aluminum oxide filler consists solely of α-alumina, with a uniform particle size and shape, resulting in a relatively low bulk density, significantly impacting electrical performance. In Comparative Examples 6 and 7, the use of a single curing agent not only impacts physical properties such as heat resistance and weather resistance, but also impacts pressure resistance.

[0041] In summary, the present invention uses a modified high molecular weight epoxy resin as the main resin, combined with composite fillers of different particle sizes and shapes, dual curing agents, antioxidants and other raw materials, to obtain an insulating thermally conductive adhesive with good dispersibility, flexibility, and density, and a high thermal conductivity coefficient. It is suitable for the production of insulating thermally conductive adhesive films and copper-clad laminates, has good thermal and electrical properties, and excellent mechanical properties, and can meet the material performance requirements of superconducting aluminum-based copper-clad laminates in printed circuit boards.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or some technical features can be replaced by equivalents, which should all be included in the scope of the technical solutions requested for protection in this application.

Claims

1. An insulating thermally conductive adhesive, characterized in that: The insulating thermal conductive adhesive comprises the following raw material components by weight: 8-10 parts of modified epoxy resin, 2-3 parts of nitrile rubber, 70-75 parts of filler, 5-6 parts of curing agent, 0.1-0.3 parts of antioxidant, and 10-15 parts of organic solvent. The molecular weight of the modified epoxy resin is 28,000-32,000.

2. The insulating thermally conductive adhesive according to claim 1, characterized in that: The modified epoxy resin is prepared by: subjecting bisphenol A epoxy resin and bisphenol A to a chain extension reaction under catalyst conditions, monitoring the molecular weight in real time through GPC, terminating the reaction when the molecular weight reaches a desired molecular weight, then uniformly mixing with maleic anhydride-terminated polyethersulfone, adding an initiator, and obtaining the modified epoxy resin after the reaction is completed.

3. The insulating thermally conductive adhesive according to claim 2, characterized in that: The amount of bisphenol A used is 0.8-1.2 times the molar amount of the bisphenol A epoxy resin; the catalyst is triethanolamine or tetrabutylammonium bromide, and the amount used is 0.3-0.5% of the total mass of the bisphenol A epoxy resin; the temperature of the chain extension reaction is 120-140°C, and the time is 2-4 hours; the amount of the maleic anhydride-terminated polyethersulfone used is 0.3-0.5 times the molar amount of the bisphenol A epoxy resin; the initiator is benzoyl peroxide, and the amount used is 0.5-1% of the total mass of the bisphenol A epoxy resin; the reaction temperature is 80-120°C, and the time is 3-5 hours.

4. The insulating thermally conductive adhesive according to claim 1, characterized in that: The filler is a composition with a mass ratio of magnesium oxide to aluminum oxide of 7-8:8-9.

5. The insulating thermally conductive adhesive according to claim 4, characterized in that: The particle size D50 of the magnesium oxide is 5 μm; the aluminum oxide is a composition of aluminum oxides of different particle sizes and shapes, wherein spherical aluminum oxide with a D50 of 5 μm accounts for 65-80%, spherical aluminum oxide with a D50 of 2 μm accounts for 5-10%, and α-alumina with a D50 of 5 μm accounts for 15-25%.

6. The insulating thermally conductive adhesive according to claim 1, characterized in that: The curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 1.8-2.5:

1.

7. The insulating thermally conductive adhesive according to claim 1, characterized in that: The antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:1-3; and the organic solvent is dimethylformamide.

8. The method for preparing an insulating thermally conductive adhesive according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) Pour half of the organic solvent into a stainless steel barrel according to the ratio, then pour in the curing agent and start stirring until the solution is completely transparent and clear; (2) Pour the other half of the organic solvent into the mixing tank according to the ratio, add the modified epoxy resin and nitrile rubber in turn, cover the tank, and start stirring until dissolved; (3) Pour the clarified liquid from step (1) into the glue mixing tank from step (2), cover the tank, and start stirring for more than 1 hour until glue is formed; (4) Pour the glue obtained in step (3) into the disperser, adjust the speed, add the filler once while stirring, and then start high-speed shear stirring and stir for more than 1.5 hours; (5) The slurry obtained in step (4) is introduced into a grinder for grinding, wherein the mixing tank pipe is connected to the grinder feed port, the grinder feed port is connected to a 10000GS magnetic filter, the grinder outlet is filtered with a 150 mesh polyester mesh, the receiving barrel is covered with a layer of 150 mesh filter mesh, and after filtering, the material is introduced into a storage tank for standby use; (6) Seal the glue ground in step (5), stir at high speed for 4-5 hours, then reduce the speed and stir for 8-10 hours. Place a 10000GS magnetic rod in the barrel during the stirring process. (7) The glue that has fully reacted in step (6) is vacuumized to obtain the product.

9. The method for preparing an insulating thermally conductive adhesive according to claim 8, characterized in that: In step (3), the stirring speed is 500 rpm; in step (4), the speed is adjusted to 200-300 rpm, the high-speed shear speed is 700-800 rpm, and the temperature is ≤70°C; in step (5), the grinder speed is 800-1200 r / min, grinding is performed 2-3 times, and the grinder chamber temperature is 60-80°C.

10. A superconducting aluminum-based copper-clad laminate, characterized in that: The superconducting aluminum-based copper-clad laminate comprises an insulating thermally conductive adhesive film obtained by curing the insulating thermally conductive adhesive according to any one of claims 1 to 7; the thickness of the insulating thermally conductive adhesive film is 30 μm.

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