An insulating heat-conducting adhesive, a superconducting aluminum-based copper-clad plate and a preparation method of the insulating heat-conducting adhesive

Abstract

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

Description

Technical Field

[0001] This invention relates to the field of thermally conductive adhesives and copper-clad laminates, specifically to an insulating thermally conductive adhesive, a superconducting aluminum-based copper-clad laminate, and a method for preparing the insulating thermally conductive adhesive. Background Technology

[0002] Aluminum-based copper-clad laminate (CCL) is a plate-like material made by impregnating electronic fiberglass cloth or other reinforcing materials with resin or single resin as an insulating adhesive layer, covering one or both sides with copper foil, and then hot-pressing it. As a substrate material in printed circuit board (PCB) manufacturing, CCL primarily serves to interconnect, insulate, and support the PCB. It significantly impacts signal transmission speed, energy loss, and characteristic impedance. The performance, quality, manufacturability, manufacturing level, manufacturing cost, and long-term reliability and stability of the PCB largely depend on the CCL. Furthermore, as a core heat dissipation component, its thermal conductivity and structural stability directly determine the reliability and lifespan of electronic equipment.

[0003] Thermally conductive adhesives, as the thermal interface material for copper-clad laminates (CCLs), play a crucial role in filling the gaps between devices and heat sinks and improving heat transfer efficiency. Traditional epoxy resin-based thermally conductive adhesives are brittle due to their high cross-linking density, making them prone to cracking under thermal stress or mechanical impact. For example, the insulating layer of conventional aluminum-based CCLs uses fiberglass-reinforced prepregs, whose rigid structure is susceptible to delamination or fracture due to stress concentration during three-dimensional machining. Furthermore, existing technologies often use fillers of a single particle size, which easily agglomerate to form pores and have poor compatibility with the matrix, resulting in discontinuous thermal conductivity pathways and low thermal conductivity. Simultaneously, the weak interfacial bonding between the filler and the matrix leads to severe phonon scattering, further reducing the effective thermal conductivity. In addition, existing technologies generally employ a single curing system, resulting in poor temperature resistance; they are prone to softening failure and delamination under high temperature and pressure, which further accelerates the thermal decomposition of the CCL adhesive, directly affecting the reliability and lifespan of electronic devices. Therefore, developing a novel insulating and thermally conductive adhesive holds promise for solving these problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an insulating thermally conductive adhesive, a superconducting aluminum-based copper-clad laminate, and a method for preparing the insulating thermally conductive adhesive. The insulating thermally conductive adhesive prepared by the present invention has good flexibility, density, heat resistance, and high thermal conductivity, making it suitable for use in superconducting copper-clad laminates, and exhibiting excellent overall performance.

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

[0006] The application provides an insulating heat-conducting adhesive, which comprises the following components in parts by weight: modified epoxy resin 8-10 parts, butyronitrile rubber 2-3 parts, filler 70-75 parts, curing agent 5-6 parts, antioxidant 0.1-0.3 parts, and organic solvent 10-15 parts, wherein the molecular weight of the modified epoxy resin is 28000-32000.

[0007] According to a further technical scheme, the preparation method of the modified epoxy resin comprises the following steps: performing chain extension reaction on bisphenol A type epoxy resin and bisphenol A under the condition of a catalyst, monitoring the molecular weight in real time through GPC, terminating the reaction when the molecular weight reaches the required molecular weight, then mixing with maleic anhydride end-capped polyether sulfone, adding an initiator, and obtaining the modified epoxy resin after the reaction.

[0008] Further, the use amount of the bisphenol A is 0.8-1.2 times the molar amount of the bisphenol A type epoxy resin; the catalyst is triethanolamine or tetrabutylammonium bromide, and the use amount is 0.3-0.5% of the total mass of the bisphenol A type epoxy resin; the chain extension reaction is performed at a temperature of 120-140 DEG C for 2-4 hours; the use amount of the maleic anhydride end-capped polyether sulfone is 0.3-0.5 times the molar amount of the bisphenol A type epoxy resin; the initiator is benzoyl peroxide, and the use amount is 0.5-1% of the total mass of the bisphenol A type epoxy resin; and the reaction is performed at a temperature of 80-120 DEG C for 3-5 hours.

[0009] Specifically, the bisphenol A type epoxy resin and bisphenol A are mixed according to a molar ratio of 1:0.8-1.2, 0.3-0.5% of the catalyst triethanolamine or tetrabutylammonium bromide is added, chain extension reaction is performed at 120-140 DEG C for 2-4 hours, the molecular weight is monitored in real time through GPC, 0.5-0.8% of mercaptopropionic acid is added to terminate the reaction when the molecular weight reaches about 25000, then 0.3-0.5 times the molar amount of the bisphenol A type epoxy resin of maleic anhydride end-capped polyether sulfone is added to mix uniformly, 0.5-1% of benzoyl peroxide is added, and the reaction is performed at 80-120 DEG C for 3-5 hours, thereby obtaining the modified epoxy resin.

[0010] The application introduces the repeating unit into the main chain by ring-opening addition reaction of the epoxy group with the hydroxyl group / epoxy group of the chain extender bisphenol A, gradually increases the molecular weight, then embeds the flexible chain segment (maleic anhydride-terminated polyether sulfone) into the epoxy main chain through free radical copolymerization / open ring grafting, reduces the crosslinking density, and enhances the flexibility of the epoxy resin.

[0011] According to a further technical solution, the filler is a composition of magnesium oxide and aluminum oxide with a mass ratio of 7-8:8-9. In the technical solution, the filler adopts a plurality of composite materials, and in particular, the use of magnesium oxide can greatly improve the thermal conductivity of the material.

[0012] Preferably, the particle size D50 of the magnesium oxide is 5 microns; the aluminum oxide is a composition of different particle sizes and different shapes of aluminum oxide, wherein the spherical aluminum oxide with a D50 of 5 microns accounts for 65-80%, the spherical aluminum oxide with a D50 of 2 microns accounts for 5-10%, and the alpha-aluminum oxide with a D50 of 5 microns accounts for 15-25%. Magnesium oxide is an insulating material with high thermal conductivity, and the addition of the filler can significantly improve the thermal conductivity of the glue. The present application uses different fillers with different particle sizes and different shapes, so that the packing density of the filler is large and the filling amount is maximized. Not only can the thermal conductivity be significantly improved, but also the rigidity and creep resistance can be enhanced, the mechanical properties are excellent, and the cost is low.

[0013] According to a further technical solution, the curing agent is a mixture of diamino diphenyl sulfone and dicyandiamide with a mass ratio of 1.8-2.5:1. After the epoxy is cured by diamino diphenyl sulfone (DDS), the curing system has high heat resistance, yellowing resistance and chemical stability, can maintain stability at high temperature environment, makes the glass transition temperature Tg point of the material higher, but the brittleness of the cured product is larger. As a curing accelerator, dicyandiamide (Dicy) can make the epoxy resin crosslink at a relatively low curing temperature. After the epoxy is cured, the material has high solvent resistance and chemical corrosion resistance, and high light resistance, so that the material has better weather resistance and ultraviolet resistance. The present application adopts a double curing agent combination technology, which can effectively reduce the temperature of the crosslinking reaction, and the obtained material has high temperature stability, chemical resistance, weather resistance and high pressure resistance.

[0014] According to a further technical solution, the antioxidant is a mixture of V-992B and UV-1050 with a mass ratio of 1:1-3; and the organic solvent is dimethylformamide. V-992B is an epoxy resin high-temperature system design that can inhibit molecular oxidation degradation at high temperature and reduce the risk of yellowing. UV-1050, also known as an anti-yellowing additive, has strong ultraviolet absorption capacity in the full wave band and can resist high-temperature oxidation. In the technical solution, the combination of the two can maximize the yellowing resistance of the material at a temperature below 200℃.

[0015] Another aspect of the present application provides a preparation method of the above-mentioned insulating and heat-conducting adhesive, comprising the following steps:

[0016] (1) According to the proportion, pour half of the organic solvent into a stainless steel barrel, then pour the curing agent, start stirring, and stop until the solution is completely transparent and clear;

[0017] (2) According to the proportion, pour the other half of the organic solvent into the glue mixing tank, add the modified epoxy resin and nitrile rubber in turn, cover the tank cover, and start stirring until dissolved;

[0018] (3) Pour the clear solution of step (1) into the glue mixing tank of step (2), cover the tank cover, and start stirring for more than 1 hour until the glue water is formed;

[0019] (4) Pour the glue water obtained in step (3) into a dispersing machine, adjust the speed, add the filler and antioxidant in turn while stirring, and then start high-speed shearing stirring and stir for more than 1.5 hours;

[0020] (5) The slurry obtained in step (4) is introduced into a grinding machine for grinding, wherein the glue mixing tank pipeline is connected to the feeding port of the grinding machine, the feeding port of the grinding machine is connected to a 10000GS magnetic filter, the outlet of the grinding machine is filtered with a 150 mesh polyester screen gauze, and a layer of 150 mesh filter gauze is covered on the outlet of the receiving barrel. After filtration, the material is introduced into the storage tank for use;

[0021] (6) The glue water of step (5) is sealed and stirred at high speed for 4-5 hours, and then the stirring speed is reduced for 8-10 hours. A 10000GS magnetic bar is placed in the barrel during the stirring process; The magnetic bar can absorb metal impurities in the material and improve the stability of the material;

[0022] (7) The glue water of step (6) is vacuumized, and the insulating and heat-conducting adhesive is obtained.

[0023] Further, the stirring speed in step (3) is 500 rpm; the adjusting speed in step (4) is 200-300 rpm, the high-speed shearing speed is 700-800 rpm, and the temperature is ≤70℃; in step (5), the grinding machine rotates at 800-1200 r / min, and the grinding is performed 2-3 times, and the cavity temperature of the grinding machine is 60-80℃.

[0024] Another aspect of the present application provides an insulating and heat-conducting adhesive film. The above-mentioned insulating and heat-conducting adhesive is supplied to the glue tank of the coating head, and the glue is coated on the release film by the coating equipment. The thickness of the glue is adjusted by the gap of the scraper, and the thickness is adjusted to 30μm. The insulating and heat-conducting adhesive is baked from low temperature to high temperature in the oven to form a semi-cured film, and then cut into a sheet to obtain the insulating and heat-conducting adhesive film.

[0025] Yet another aspect of the present application provides a superconducting aluminum-based copper-clad plate comprising the cured insulating heat-conductive adhesive film described above, wherein the thickness of the insulating heat-conductive adhesive film is 30 μm. The superconducting aluminum-based copper-clad plate is obtained by laminating two layers of the insulating heat-conductive adhesive film described above with a copper foil and an aluminum plate.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The present application uses modified high molecular weight epoxy resin as the main resin, which has good flexibility and can improve the material's resistance to elastic deformation and breaking; the filler is selected from a plurality of composite fillers with different particle sizes and shapes, which are stacked and embedded in each other to maximize the filling amount, increase the bulk density and improve the material's thermal conductivity, high pressure resistance and mechanical properties; the use of dual curing agents takes full advantage of both and improves the material's high temperature stability, chemical resistance, weather resistance and high pressure resistance.

[0028] The present application mixes and stirs in multiple steps, uses a magnetic rod to remove metal impurities in the material during preparation, and uses multiple grinding to fully disperse the fillers in the epoxy resin, prevent caking and sedimentation, and eliminate air bubbles by vacuumizing. The obtained insulating heat-conductive adhesive has good dispersibility, flexibility, compactness, high thermal conductivity, is suitable for making insulating heat-conductive adhesive film and copper-clad plate, has good thermal and electrical properties, excellent mechanical properties, and can meet the material performance requirements of superconducting aluminum-based copper-clad plate in printed circuit boards. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. The described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] The raw materials used in the following examples and comparative examples of the present application are as follows:

[0031] Bisphenol A type epoxy resin (E-51, supplier: Dow Chemical); butyl nitrile rubber (XL2740, supplier: Hengshui Enrui Rubber and Plastic); bisphenol A (BPA, supplier: Dow Chemical); mercaptopropionic acid (supplier: Dow Chemical); benzoyl peroxide (BPO, supplier: Arkema); maleic anhydride-terminated polyether sulfone (PES-MA, supplier: Solvay); magnesium oxide (supplier: China Magnesium Industry); aluminum oxide (supplier: China Aluminum Industry); diamino diphenyl sulfone (DDS, supplier: Suzhou Yunfeng); dicyandiamide (Dicy, supplier: Merck); dimethylformamide (supplier: Merck); V-992B (supplier: Gade Chemical); UV-1050 (supplier: Nanjing Jingtianwei Chemical).

[0032] The method is a conventional method unless otherwise specified, and the raw material can be obtained from a public commercial channel unless otherwise specified.

[0033] Example 1

[0034] Preparation method of modified epoxy resin: Bisphenol A type epoxy resin and bisphenol A were mixed in a molar ratio of 1:0.8, 0.3% of catalyst triethanolamine or tetrabutylammonium bromide was added, chain extension reaction was carried out at 140℃ for 4h, and the molecular weight was monitored in real time by GPC, when the molecular weight reached about 25000, 0.5% of mercaptopropionic acid was added to terminate the reaction, then 0.3 times the molar amount of maleic anhydride-terminated polyether sulfone of bisphenol A type epoxy resin was added and mixed uniformly, 0.5% of benzoyl peroxide was added, and reaction was carried out at 80℃ for 3h to obtain the modified epoxy resin, and the molecular weight was detected as 28500.

[0035] Example 2

[0036] Preparation method of modified epoxy resin: Bisphenol A type epoxy resin and bisphenol A were mixed in a molar ratio of 1:1, 0.4% of catalyst triethanolamine or tetrabutylammonium bromide was added, chain extension reaction was carried out at 130℃ for 3h, and the molecular weight was monitored in real time by GPC, when the molecular weight reached about 25000, 0.6% of mercaptopropionic acid was added to terminate the reaction, then 0.4 times the molar amount of maleic anhydride-terminated polyether sulfone of bisphenol A type epoxy resin was added and mixed uniformly, 0.7% of benzoyl peroxide was added, and reaction was carried out at 100℃ for 4h to obtain the modified epoxy resin, and the molecular weight was detected as 29500.

[0037] Example 3

[0038] The preparation method of the modified epoxy resin comprises the following steps: mixing bisphenol A type epoxy resin and bisphenol A according to a molar ratio of 1:1.2, adding 0.5% of a catalyst triethanolamine or tetrabutylammonium bromide, carrying out chain extension reaction at 120°C for 3h, and monitoring the molecular weight in real time through GPC; when the molecular weight reaches about 25000, adding 0.8% of mercaptopropionic acid to terminate the reaction, then adding 0.5 times of the molar amount of maleic anhydride of the bisphenol A type epoxy resin to cap the polyether sulfone, mixing uniformly, adding 1% of benzoyl peroxide, and reacting at 120°C for 5h to obtain the modified epoxy resin, and the molecular weight of the modified epoxy resin is 31000.

[0039] Example 4

[0040] The insulating and heat-conducting adhesive comprises the following raw material components in parts by weight: 8 parts of the modified epoxy resin obtained in Example 1, 2 parts of nitrile rubber, 70 parts of fillers, 5 parts of a curing agent, 0.1 part of an antioxidant, and 10 parts of dimethylformamide, wherein,

[0041] The fillers are a composition of magnesium oxide and aluminum oxide in a mass ratio of 7:8, the particle size D50 of the magnesium oxide is 5μm, the spherical aluminum oxide with D50 of 5μm accounts for 65%, the spherical aluminum oxide with D50 of 2μm accounts for 10%, and the α-aluminum oxide with D50 of 5μm accounts for 25%; the curing agent is a mixture of diamino diphenyl sulfone and dicyandiamide in a mass ratio of 1.8:1; and the antioxidant is a mixture of V-992B and UV-1050 in a mass ratio of 1:1.

[0042] The preparation method comprises the following steps:

[0043] (1) according to the proportion, pour half of the organic solvent into a stainless steel barrel, then pour in the curing agent, start stirring (300rpm), and the solution is completely transparent and clear;

[0044] (2) according to the proportion, pour the other half of the organic solvent into the glue mixing tank, add the modified epoxy resin and nitrile rubber in turn, cover the tank cover, start stirring (300rpm) until dissolved;

[0045] (3) pour the clear solution of step (1) into the glue mixing tank of step (2), cover the tank cover, start stirring (500rpm) for more than 1h, and the glue water is obtained;

[0046] (4) pour the glue water obtained in step (3) into a dispersing machine, adjust the speed, add the fillers and the antioxidant in turn while stirring (300rpm), and then start high-speed shearing stirring (700rpm, temperature below 70°C) for more than 1.5h;

[0047] (5) The slurry obtained in step (4) is introduced into a grinder (800-1200 r / min) for grinding, wherein the glue mixing tank pipeline is connected to the grinder inlet, the grinder inlet is connected to a 10000GS magnetic filter, the grinder outlet is filtered with a 150 mesh polyester screen gauze, and the receiving barrel is covered with a layer of 150 mesh filter gauze. After filtration, the material is introduced into a storage tank for use. The grinding is performed twice, and the grinder is filled with zirconia beads with a particle size of 1.6 mm;

[0048] (6) The glue obtained in step (5) is sealed and stirred at high speed (600 rpm) for 4-5 h, and then the stirring speed is reduced (200 rpm) for 8-10 h. During the stirring process, a 10000GS magnetic bar is placed in the barrel to remove metal impurities in the glue;

[0049] (7) The glue obtained in step (6) is vacuumized.

[0050] Example 5

[0051] An insulating and heat-conducting glue, by weight, comprises the following raw material components: 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,

[0052] The filler is a composition of magnesium oxide and aluminum oxide with a mass ratio of 7:9. The particle size D50 of the magnesium oxide is 5 μm. In the aluminum oxide, 70% is spherical aluminum oxide with a D50 of 5 μm, 8% is spherical aluminum oxide with a D50 of 2 μm, and 22% is α-aluminum oxide with a D50 of 5 μm. The curing agent is a mixture of diamino diphenyl sulfone and dicyandiamide with a mass ratio of 2:1. The antioxidant is a mixture of V-992B and UV-1050 with a mass ratio of 1:2. The preparation method is the same as that of Example 4.

[0053] Example 6

[0054] An insulating and heat-conducting glue, by weight, comprises the following raw material components: 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,

[0055] The filler is a composition of magnesium oxide and aluminum oxide with a mass ratio of 8:9. The particle size D50 of the magnesium oxide is 5 μm. In the aluminum oxide, 80% is spherical aluminum oxide with a D50 of 5 μm, 5% is spherical aluminum oxide with a D50 of 2 μm, and 15% is α-aluminum oxide with a D50 of 5 μm. The curing agent is a mixture of diamino diphenyl sulfone and dicyandiamide with a mass ratio of 2.5:1. The antioxidant is a mixture of V-992B and UV-1050 with a mass ratio of 1:3. The preparation method is the same as that of Example 4.

[0056] Comparative Example 1

[0057] The preparation method of the modified epoxy resin is as follows: the bisphenol A type epoxy resin is mixed with bisphenol A at a molar ratio of 1:1.2, 0.3% of a catalyst triethanolamine or tetrabutylammonium bromide is added, chain extension reaction is carried out at 140°C for 4h, and the molecular weight is monitored in real time by GPC, when the molecular weight reaches about 28000, 0.5% of mercaptopropionic acid is added to terminate the reaction, and the modified epoxy resin is obtained, and the molecular weight is detected as 28400.

[0058] Comparative Example 2

[0059] An insulating and heat-conducting adhesive, which is different from Example 4 in that the epoxy resin used is a bisphenol A type epoxy resin.

[0060] Comparative Example 3

[0061] An insulating and heat-conducting adhesive, which is different from Example 4 in that the modified epoxy resin used is obtained by the method of Comparative Example 1.

[0062] Comparative Example 4

[0063] An insulating and heat-conducting adhesive, which is different from Example 4 in that there is no magnesium oxide in the filler used.

[0064] Comparative Example 5

[0065] An insulating and heat-conducting adhesive, which is different from Example 4 in that the filler used is a combination of magnesium oxide and alpha-alumina.

[0066] Comparative Example 6

[0067] An insulating and heat-conducting adhesive, which is different from Example 4 in that the curing agent used is DDS.

[0068] Comparative Example 7

[0069] An insulating and heat-conducting adhesive, which is different from Example 4 in that the curing agent used is Dicy.

[0070] The insulating and heat-conducting adhesives prepared in Examples 4-6 and Comparative Examples 2-7 above are first prepared into insulating and heat-conducting adhesive films by the following method: the insulating and heat-conducting adhesive is supplied to a coating head tank, and the adhesive is coated onto a release film using a coating device with a doctor blade, the thickness of the adhesive is adjusted by the gap of the doctor blade, and the thickness is adjusted to 30μm, the insulating and heat-conducting adhesive is baked in an oven from low temperature to high temperature to a semi-cured film state, and then cut into a sheet shape to obtain, and the mechanical properties of the insulating and heat-conducting adhesive film are detected. Then two layers of insulating and heat-conducting adhesive film are combined with copper foil and aluminum plate at 180°C and 500PSI to obtain superconducting aluminum-based copper-clad plate, and the related properties are detected, and the results are shown in Tables 1 and 2.

[0071] Table 1 Performance test results of sample of example 4-6

[0072]

[0073] Table 2 Performance test results of sample of comparative example 2-7

[0074]

[0075] From the test results of table 1 and table 2, it can be seen that the insulation heat conductive adhesive film prepared by using the formulation and preparation method of the present application has excellent mechanical properties and anti-aging properties, and after being used for copper-clad plate, the overall performance is excellent, especially the thermal conductivity is high, and the heat resistance and pressure resistance are good. In comparative example 2, the used epoxy resin is not modified, so the mechanical properties of the insulation heat conductive adhesive film are poor, which affects other properties to some extent; in comparative example 3, the epoxy resin is modified without introducing a flexible segment, so the mechanical properties are slightly poor; in comparative example 4, magnesium oxide is not used as the filler, although the mechanical properties are not greatly affected, the thermal conductivity is too low; in comparative example 5, the filler is only α-aluminum oxide, and the particle size and shape are single, so the packing density is relatively small, which seriously affects the electrical properties; in comparative examples 6 and 7, the use of a single curing agent not only affects the physical properties such as temperature resistance and weather resistance, but also affects the pressure resistance.

[0076] In summary, the modified high molecular weight epoxy resin is used as the main resin, and different particle size, different shape and multiple varieties of composite fillers, double curing agents, antioxidants and other raw materials are used, so that the insulation heat conductive adhesive obtained has good dispersibility, flexibility and compactness, high thermal conductivity, is suitable for making insulation heat conductive adhesive film and copper-clad plate, has good thermal and electrical properties, excellent mechanical properties, and can meet the material performance requirements of superconducting aluminum-based copper-clad plate in printed circuit board.

[0077] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones, which should be covered in the technical solution range claimed by the present application.

Claims

1. An insulating heat-conductive paste, characterized by, The insulating and heat-conducting glue comprises the following components by weight: modified epoxy resin 8-10 parts, nitrile rubber 2-3 parts, filler 70-75 parts, curing agent 5-6 parts, antioxidant 0.1-0.3 parts, and organic solvent 10-15 parts; the molecular weight of the modified epoxy resin is 28000-32000; The preparation method of the modified epoxy resin comprises the following steps: chain extension reaction of bisphenol A type epoxy resin and bisphenol A under the condition of a catalyst, real-time monitoring of the molecular weight by GPC, termination of the reaction when the molecular weight reaches the required value, mixing of the modified epoxy resin with maleic anhydride end-capped polyether sulfone, addition of an initiator, and obtaining of the modified epoxy resin after the reaction; the amount of the bisphenol A is 0.8-1.2 times the molar amount of the bisphenol A type epoxy resin; the chain extension reaction is carried out at a temperature of 120-140℃ for 2-4 hours; and the amount of the maleic anhydride end-capped polyether sulfone is 0.3-0.5 times the molar amount of the bisphenol A type epoxy resin; The filler is a composition of magnesium oxide and aluminum oxide in a mass ratio of 7-8:8-9; the aluminum oxide is a composition of aluminum oxide with different particle sizes and shapes, wherein spherical aluminum oxide with a D50 of 5μm accounts for 65-80%, spherical aluminum oxide with a D50 of 2μm accounts for 5-10%, and α-aluminum oxide with a D50 of 5μm accounts for 15-25%; The curing agent is a mixture of diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 1.8-2.5:1; 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.

2. The insulating and heat-conducting adhesive according to claim 1, wherein The catalyst is triethanolamine or tetrabutylammonium bromide, and the amount of the catalyst is 0.3-0.5% of the total mass of the bisphenol A type epoxy resin; the initiator is benzoyl peroxide, and the amount of the initiator is 0.5-1% of the total mass of the bisphenol A type epoxy resin; the reaction temperature is 80-120℃, and the reaction time is 3-5 hours.

3. The insulating and heat-conducting adhesive according to claim 1, wherein The particle size D50 of the magnesium oxide is 5μm.

4. A method for preparing an insulating and thermally conductive adhesive as described in any one of claims 1-3, characterized in that, The preparation method comprises the following steps: (1) according to the proportion, pour half of the organic solvent into a stainless steel barrel, then pour in the curing agent, start stirring, and stop when the solution is completely transparent and clear; (2) according to the proportion, pour the other half of the organic solvent into a glue mixing tank, then add the modified epoxy resin and nitrile rubber in sequence, cover the tank cover, and start stirring until the solution is dissolved; (3) pour the clear solution of step (1) into the glue mixing tank of step (2), cover the tank cover, and start stirring for more than 1 hour until the glue water is obtained; (4) pour the glue water obtained in step (3) into a dispersing machine, adjust the rotating speed, add the filler and antioxidant in sequence while stirring, and then start high-speed shearing stirring and stir for more than 1.5 hours; (5) introduce the slurry obtained in step (4) into a grinding machine for grinding, wherein the glue mixing tank pipeline is connected to the feeding port of the grinding machine, the feeding port of the grinding machine is connected to a 10000GS magnetic filter, the outlet of the grinding machine is filtered with 150-mesh polyester screen gauze, the tank opening is covered with a layer of 150-mesh filter gauze, and the material is introduced into a storage tank after filtration for later use. (6) The glue of step (5) is sealed and stirred at high speed for 4-5 h, and then stirred at low speed for 8-10 h. A 10000 GS magnetic force rod is placed in the barrel during the stirring process; (7) The glue of step (6) is vacuumized, and the glue is obtained.

5. The method for preparing an insulating and thermally conductive adhesive according to claim 4, characterized in that, The stirring speed in step (3) is 500 rpm; the adjusting speed in step (4) is 200-300 rpm, the high-speed shearing speed is 700-800 rpm, and the temperature is ≤70℃; the speed of the grinder in step (5) is 800-1200 r / min, the grinding is performed for 2-3 times, and the temperature of the cavity of the grinder is 60-80℃.

6. A superconducting aluminum-based copper clad sheet characterized by, The superconducting aluminum-based copper-clad plate comprises the insulating and heat-conducting glue film after the insulating and heat-conducting glue of any one of claims 1-3 is cured; and the thickness of the insulating and heat-conducting glue film is 30 μm.

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