High-temperature-resistant heat-conducting epoxy potting material and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant heat-conducting epoxy potting material and a preparation method thereof, and the high-temperature-resistant heat-conducting epoxy potting material comprises the following components in parts by mass: 100 parts by mass of epoxy resin based on the parts by mass of epoxy resin; 100 to 110 parts by mass of a curing agent; 0.6 to 0.8 part by mass of an accelerant; 400-550 parts by mass of a thermally conductive filler; 15 to 30 parts by mass of a toughening agent; wherein the epoxy resin is selected from at least one of novolac epoxy resin and low-viscosity epoxy resin; the low-viscosity epoxy resin is selected from at least one of low-viscosity ring group glycidyl ester type three-functionality epoxy resin and low-viscosity ring group glycidyl ether epoxy resin; the heat-conducting filler is selected from at least one of aluminum oxide, aluminum nitride, boron nitride and magnesium oxide. The use temperature of the high-temperature-resistant heat-conducting epoxy resin potting material prepared by the technical scheme can reach 180 DEG C, and the high-temperature-resistant heat-conducting epoxy resin potting material is good in heat conductivity and toughness, has relatively good mechanical strength, can be used for a long time at the temperature of (-55)-180 DEG C, and can be used for packaging windings and power devices.

Description

Technical Field

[0001] The present invention relates to but is not limited to the technical field of material technology, and in particular to a high temperature resistant thermal conductive epoxy potting material and a preparation method thereof. Background Art

[0002] Thermally conductive potting compound is a sealing material with good thermal conductivity. It is mainly used to fill the gaps between electronic components and devices, while providing a heat conduction path to ensure that the temperature of the device is stable during operation.

[0003] The thermal conductive potting glue currently used mainly includes three categories: epoxy resin, polyurethane and silicone. The advantage of the first two is that they have good bonding performance to the substrate, but the disadvantage is that the temperature is low. If used in high-power power supplies, relays, sensors or electronic appliances that need to be used at higher temperatures, the potting material will be decomposed and lose elasticity over a long period of time; silicone thermal conductive potting glue has high temperature resistance and linear expansion, but poor bonding ability to the substrate, but almost no bonding strength. Obviously, the existing thermal conductive potting glue has the problem of difficulty in balancing high temperature resistance and bonding strength. Summary of the invention

[0004] Purpose of the present invention: In order to solve the above technical problems, the embodiment of the present invention provides a high temperature resistant thermally conductive epoxy potting material and a preparation method thereof, so as to solve the problem that the existing thermally conductive potting glue is difficult to balance high temperature resistance and adhesion.

[0005] Technical solution of the present invention: In a first aspect, an embodiment of the present invention provides a high temperature resistant thermally conductive epoxy potting material, wherein the components of the high temperature resistant thermally conductive epoxy potting material include, by mass:

[0006] Based on the mass percentage of epoxy resin, 100 mass percentages of epoxy resin;

[0007] 100-110 parts by mass of a curing agent;

[0008] 0.6-0.8 mass parts of accelerator;

[0009] 400-550 parts by mass of thermally conductive filler;

[0010] 15 to 30 parts by weight of a toughening agent;

[0011] The epoxy resin is selected from at least one of a phenolic epoxy resin and a low-viscosity epoxy resin; the low-viscosity epoxy resin is selected from at least one of a low-viscosity cyclopentyl glycidyl ester trifunctional epoxy resin and a low-viscosity cyclopentyl glycidyl ether epoxy resin;

[0012] The thermal conductive filler is selected from at least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide.

[0013] Optionally, in the high temperature resistant thermal conductive epoxy potting material as described above,

[0014] In the epoxy resin, the phenolic epoxy resin has a large number of rigid groups and a large cross-linking density, so that the use temperature of the prepared thermal conductive epoxy potting material is at least greater than 150°;

[0015] Based on the requirements for fluidity of high temperature resistant thermal conductive epoxy potting materials in the preparation process, F-51 and F-54 brands of phenolic epoxy resin are selected, TDE-85 brand of low viscosity cyclic glycidyl ester type trifunctional epoxy resin is selected, and CER-170 brand of low viscosity cyclic glycidyl ether is selected.

[0016] Optionally, in the high temperature resistant thermal conductive epoxy potting material as described above,

[0017] The epoxy resin curing agent includes at least one of the following: an amine curing agent, an acid anhydride curing agent, and an imidazole curing agent;

[0018] Wherein, the amine curing agent includes: one of dicyandiamide, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, and diphenylmethane;

[0019] The anhydride curing agent is selected from at least one of the following: liquid anhydride of methyl tetracyanophthalic anhydride and methyl nadic anhydride, which is used to prepare a fluid thermal conductive epoxy potting material; wherein the kinematic viscosity of the high temperature resistant thermal conductive epoxy potting material is 1000-5000cps;

[0020] The imidazole curing agent is used to cure epoxy resin alone, or as an accelerator for a selected curing agent.

[0021] Optionally, in the high temperature resistant thermal conductive epoxy potting material as described above,

[0022] When the imidazole curing agent is used as the curing agent, at least one of 2-ethyl and 4-methylimidazole is selected;

[0023] When the imidazole curing agent is used as an accelerator, at least one of 2-ethyl, 4-methylimidazole, benzene ring modified imidazole, melamine modified imidazole and triisocyanate modified imidazole is selected.

[0024] Optionally, in the high temperature resistant thermal conductive epoxy potting material as described above,

[0025] The selection principles of the thermal conductive filler include:

[0026] Based on the uniformity, isotropy and potting application requirements of the prepared thermally conductive epoxy potting material, it is required to select a thermally conductive filler with insulating properties;

[0027] Based on the principle of safety, non-toxic thermal conductive fillers are selected.

[0028] Optionally, in the high temperature resistant thermal conductive epoxy potting material as described above,

[0029] The toughening agent can be selected from at least one of epoxy toughening agents and non-epoxy toughening agents;

[0030] Among them, for epoxy toughening agents, Qishi toughening agent is selected as the toughening agent for epoxy resin;

[0031] As for the non-epoxy toughening agent, at least one of polyether polyurethane, hydroxyl-terminated liquid polybutadiene rubber and carboxyl-terminated liquid polybutadiene rubber is selected as the toughening material for the epoxy resin.

[0032] In a second aspect, an embodiment of the present invention further provides a method for preparing a high temperature resistant thermally conductive epoxy potting material, which is used to prepare a high temperature resistant thermally conductive epoxy potting material as described in any one of the above items, comprising:

[0033] Step 1, selecting materials for each group used to prepare high temperature resistant thermal conductive epoxy potting material;

[0034] Step 2, dividing the components into component A and component B;

[0035] Step 3, preparing component A and component B respectively;

[0036] Step 4, mix component A and component B in proportion, and put them into a vacuum oven with a vacuum degree of 0.009 MPa at (65±5)° C. for 1 hour to ensure that the acetone is completely volatilized;

[0037] Step 5, clean the product to be potted and preheat it at (100±2)℃ for about 1 hour, then cool it down to 80±2℃ and inject the potting material into the product;

[0038] Step 6, baking and curing: (100±5)℃ / 2h+(150±5)℃ / 2h+(180±5)℃ / 3h;

[0039] Step 7: After curing is completed, the product is naturally cooled down to room temperature along with the oven and then taken out;

[0040] The mass ratio of each component in component A is: epoxy resin: toughening agent: thermal conductive filler = 100: 15-30: 400-550; the mass ratio of each component in component B is: curing agent: accelerator = 100: 0.6-0.8;

[0041] The mass ratio of component A to component B is 100:100-110.

[0042] Optionally, in the method for preparing the high temperature resistant thermally conductive epoxy potting material as described above, the preparation method of component A in step 3 comprises:

[0043] Step 31, heat the phenolic epoxy resin and the low-viscosity epoxy resin at (60-80)° C. for 1 hour to reduce their viscosity;

[0044] Step 32, alumina powder and nano aluminum nitride powder of different particle sizes are mixed in a ratio of 100:7, and then KH550 silane coupling agent and acetone are added, the addition amount of KH550 silane coupling agent is 5% of the mass fraction of the thermal conductive filler, and the addition amount of acetone is 100ml / 100g, and then the thermal conductive filler, coupling agent, acetone, toughening agent and epoxy resin are mixed according to the ratio, and stirred at a speed of 5000 rpm for 30 minutes with a high-speed disperser, and then the mixed filler and resin are placed in a vacuum oven with a vacuum degree of 0.009MPa at 80°C for 1 hour to obtain component A.

[0045] Optionally, in the method for preparing the high temperature resistant thermally conductive epoxy potting material as described above, the preparation method of component B in step 3 is:

[0046] Step 33, mix the curing agent and the accelerator according to a certain proportion, and stir them evenly to obtain component B.

[0047] Beneficial effects of the present invention: A high temperature resistant thermally conductive epoxy potting material and a preparation method thereof provided by an embodiment of the present invention, by dividing the components used for preparing the high temperature resistant thermally conductive epoxy potting material into component A and component B, and reasonably setting the mass ratio of each component in component A, the mass ratio of each component in component B, and the mass ratio of component A to component B; by reasonably selecting materials for each component (wherein the epoxy resin is selected from at least one of a phenolic epoxy resin and a low viscosity epoxy resin; the low viscosity epoxy resin is selected from at least one of a low viscosity cyclopentyl glycidyl ester type trifunctional epoxy resin and a low viscosity cyclopentyl glycidyl ether epoxy resin; and the conductive The thermal filler is selected from at least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide). A thermally conductive epoxy potting material with high temperature resistance is prepared by the above-mentioned material selection. Its operating temperature can reach 180°C, and it can be used for a long time at (-55)°C to 180°C. The thermal conductivity can reach 2.3W / m·K, and it can be used for the packaging of windings and power devices. In addition, the high temperature resistant thermally conductive epoxy potting material has small shrinkage, good dimensional stability, a wide operating temperature range, high mechanical strength, low hygroscopicity, good processability, and good crack resistance, insulation and flow properties, which can meet the potting requirements of windings and electronic components. DETAILED DESCRIPTION

[0048] To make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0049] The above background technology has already explained the application of thermal conductive potting adhesive in electronic components and equipment; however, the existing thermal conductive potting adhesive has the problem of being difficult to balance high temperature resistance and adhesion.

[0050] In order to solve the above problems, an embodiment of the present invention provides a high-temperature resistant thermally conductive epoxy potting material and a preparation method thereof. The high-temperature resistant thermally conductive epoxy potting material prepared by the preparation method provided by the present invention can be used for potting of electronic components and motor windings. Its operating temperature can reach 180°C, and its thermal conductivity can reach 2.3W / m·K. At the same time, it has good crack resistance, insulation and flow properties.

[0051] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0052] The embodiment of the present invention provides a high temperature resistant thermally conductive epoxy potting material, and the components of the high temperature resistant thermally conductive epoxy resin potting material may include: epoxy resin, curing agent, accelerator, thermal conductive filler, toughening agent and other components. Based on the mass fraction of epoxy resin, the above components, in mass fraction, specifically include:

[0053] 100 parts by mass of epoxy resin;

[0054] 100-110 parts by mass of a curing agent;

[0055] 0.6-0.8 mass parts of accelerator;

[0056] 400-5508 parts by mass of thermally conductive filler;

[0057] 15 to 308 parts by mass of a toughening agent;

[0058] It should be noted that the epoxy resin in the embodiment of the present invention is selected from at least one of a phenolic epoxy resin and a low-viscosity epoxy resin; the low-viscosity epoxy resin is selected from at least one of a low-viscosity cyclopentyl glycidyl ester type trifunctional epoxy resin and a low-viscosity cyclopentyl glycidyl ether epoxy resin;

[0059] The thermally conductive filler in the embodiment of the present invention is selected from at least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide.

[0060] The main component characteristics of the high temperature resistant thermal conductive epoxy potting material provided by the embodiment of the present invention are described in detail as follows:

[0061] 1. Epoxy resin:

[0062] The potting material provided in the embodiment of the present invention is required to have the characteristics of high operating temperature, high thermal conductivity, good toughness, high mechanical strength and good dimensional stability. Therefore, the selection principle of epoxy resin should be to select epoxy resin with high temperature resistance, low viscosity and good toughness.

[0063] According to the above principles, the epoxy resin is selected from at least one of a phenolic epoxy resin and a low-viscosity epoxy resin; wherein the low-viscosity epoxy resin is selected from at least one of a low-viscosity cyclopentyl glycidyl ester type trifunctional epoxy resin and a low-viscosity cyclopentyl glycidyl ether epoxy resin.

[0064] Since the phenolic epoxy resin has a large number of rigid groups and a large cross-linking density, the thermally conductive epoxy potting material prepared can have a higher operating temperature; for example, the operating temperature is at least greater than 150°.

[0065] Considering the processability of the potting material, that is, the requirement for fluidity of the potting material in the preparation process, the epoxy resin is preferably F-51 and F-54 brand phenolic epoxy resin. The F-51 and F-54 brand phenolic epoxy resins are viscous liquids at room temperature. After being heated to a certain temperature (70°C to 80°C), the viscosity of the resin decreases, which is conducive to the preparation and construction of the potting material.

[0066] The low-viscosity cyclic glycidyl ester type trifunctional epoxy resin is preferably TDE-85 brand, and the low-viscosity cyclic glycidyl ether is preferably CER-170 brand.

[0067] 2. Curing agent and accelerator

[0068] Commonly used curing agents for epoxy resins include at least one of the following: amine curing agents, anhydride curing agents, imidazole curing agents, and the like.

[0069] The amine curing agent includes one of the following: dicyandiamide, metaphenylenediamine, 4,4'-diaminodiphenyl sulfone, and diphenylmethane; these amine curing agents can improve the heat resistance of the thermally conductive potting material.

[0070] Anhydride curing agents have the characteristics of long service life, basically no irritation to the skin, slow curing reaction, small heat release, low shrinkage, high heat resistance of the product, excellent mechanical strength and electrical properties of the product. The anhydride curing agent is selected from at least one of the following: methyl tetracyanophthalic anhydride, methyl nadic anhydride and other liquid anhydrides. The above anhydride curing agents have the advantages of low viscosity and good processability, and can be made into potting materials with good fluidity. It should be noted that the kinematic viscosity of the high temperature resistant thermal conductive epoxy potting material in the embodiment of the present invention is 1000-5000cps.

[0071] Imidazole curing agents can cure epoxy resins alone, or they can be used as accelerators for other curing agents. For example, when dicyandiamide or anhydride curing agents are used to cure phenolic epoxy resins, imidazole curing agents are used as accelerators.

[0072] In one implementation, when an imidazole curing agent is used as a curing agent, at least one of 2-ethyl and 4-methylimidazole is selected.

[0073] In another implementation, when the imidazole curing agent is used as the accelerator, at least one of 2-ethyl, 4-methylimidazole, benzene ring modified imidazole, melamine modified imidazole and triisocyanate modified imidazole is selected.

[0074] In the following embodiments of the present invention, anhydride curing agents and imidazole curing agents are selected as accelerators for illustration.

[0075] 3. Thermally conductive filler

[0076] Thermal conductive filler is a solid that is completely different in structure from epoxy resin. Filler plays a significant role in improving certain physical properties of epoxy resin products and reducing costs.

[0077] Considering that commonly used thermally conductive fillers include carbon powder, graphene, aluminum oxide, beryllium oxide, aluminum nitride, boron nitride and magnesium oxide, etc. Since beryllium oxide is highly toxic, it is not selected for safety reasons. Carbon powder and graphene are conductive, and the thermal conductivity of graphene is directional, while the thermally conductive epoxy potting material is usually liquid and filled in various parts of the sample. The performance of the potting material is usually required to be uniform and isotropic, and the potting material is usually used to pot windings and electronic components. Therefore, the potting material is generally required to have excellent insulation properties. Based on the above requirements, the thermally conductive filler in the embodiment of the present invention can select at least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide.

[0078] 4. Toughening agent

[0079] The toughening agent used for the epoxy resin may be at least one of an epoxy toughening agent and a non-epoxy toughening agent.

[0080] In one embodiment, for epoxy toughening agents, Qishi toughening agent is selected as one of the toughening agents for epoxy resin; the Qishi toughening agent molecule contains active groups, which react with the Mars groups in the epoxy resin to form an "island structure" with the CC dispersed phase as the "island" and the connecting phase epoxy resin as the "sea", thereby achieving the purpose of toughening.

[0081] In another embodiment, for non-epoxy toughening agents, at least one of polyether polyurethane, hydroxyl-terminated liquid polybutadiene rubber and carboxyl-terminated liquid polybutadiene rubber is selected as the toughening material of epoxy resin. Among them, hydroxyl-terminated liquid polybutadiene rubber has low viscosity, aging resistance and low temperature resistance, and can improve the toughness and dimensional stability of epoxy resin at low temperatures and improve the temperature shock resistance of epoxy resin. Carboxyl-terminated liquid polybutadiene rubber has excellent cold resistance and elasticity, good adhesion, water resistance and dielectric properties, and can improve the temperature shock resistance and water resistance of epoxy resin.

[0082] 5. Coupling agent

[0083] Coupling agent: In the embodiment of the present invention, a silane coupling agent is selected as the coupling agent.

[0084] Based on the high temperature resistant thermally conductive epoxy potting material provided by the above embodiment of the present invention, the embodiment of the present invention further provides a method for preparing the high temperature resistant thermally conductive epoxy potting material, which is used to prepare the high temperature resistant thermally conductive epoxy potting material provided by any of the above embodiments, and the preparation method comprises:

[0085] Step 1, selecting materials for each group used to prepare high temperature resistant thermal conductive epoxy potting material;

[0086] Step 2, dividing the components into component A and component B;

[0087] Step 3, preparing component A and component B respectively;

[0088] Step 4, mix component A and component B in proportion, and put them into a vacuum oven with a vacuum degree of 0.009 MPa at (65±5)° C. for 1 hour to ensure that the acetone is completely volatilized.

[0089] Step 5: Clean the product to be potted and preheat it at (100±2)℃ for about 1 hour, then cool it to 80±2℃ and inject the potting material into the product.

[0090] Step 6, baking and curing: (100±5)℃ / 2h+(150±5)℃ / 2h+(180±5)℃ / 3h.

[0091] Step 7: After curing is completed, the product is naturally cooled to room temperature along with the oven before being taken out.

[0092] In the embodiment of the present invention, the mass ratio of each component in component A is: epoxy resin: toughening agent: thermal conductive filler = 100: 15-30: 400-550; the mass ratio of each component in component B is: curing agent: accelerator = 100: 0.6-0.8; and the mass ratio of component A to component B is 100: 100-110.

[0093] In one implementation of the embodiment of the present invention, the preparation method of component A in step 3 includes:

[0094] Step 31, keeping the phenolic epoxy resin and the low-viscosity epoxy resin at (60-80)° C. for 1 hour to reduce their viscosity;

[0095] Step 32, alumina powder and nano aluminum nitride powder of different particle sizes are mixed in a ratio of 100:7, and then KH550 silane coupling agent and acetone are added, the addition amount of KH550 silane coupling agent is 5% of the mass fraction of the thermal conductive filler, and the addition amount of acetone is 100ml / 100g, and then the thermal conductive filler, coupling agent, acetone, toughening agent and epoxy resin are mixed according to the ratio, and stirred at a speed of 5000 rpm for 30 minutes with a high-speed disperser, and then the mixed filler and resin are placed in a vacuum oven with a vacuum degree of 0.009MPa at 80°C for 1 hour to obtain component A.

[0096] In addition, the preparation method of component B in step 3 is:

[0097] Step 33, mix the curing agent and the accelerator according to a certain proportion, and stir them evenly to obtain component B.

[0098] The high temperature resistant heat conductive epoxy potting material and the preparation method thereof provided by the embodiment of the present invention are as follows: the components used for preparing the high temperature resistant heat conductive epoxy potting material are divided into component A and component B, and the mass ratio of each component in component A, the mass ratio of each component in component B, and the mass ratio of component A to component B are reasonably set; by reasonably selecting materials for each component (wherein, the epoxy resin is selected from at least one of a phenolic epoxy resin and a low viscosity epoxy resin; the low viscosity epoxy resin is selected from at least one of a low viscosity cyclopentyl glycidyl ester type trifunctional epoxy resin and a low viscosity cyclopentyl glycidyl ether epoxy resin; and the thermal conductive filler is selected from At least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide). A thermally conductive epoxy potting material with high temperature resistance is prepared by the above material selection. The use temperature of the thermally conductive epoxy potting material can reach 180°C, and it can be used for a long time at (-55)°C to 180°C. The thermal conductivity can reach 2.3W / m·K, and it can be used for the packaging of windings and power devices. In addition, the high temperature resistant thermally conductive epoxy potting material has small shrinkage, good dimensional stability, a wide operating temperature range, high mechanical strength, low hygroscopicity, good processability, and good crack resistance, insulation and flow properties, which can meet the potting requirements of windings and electronic components.

[0099] The following is a schematic illustration of the implementation of the method for preparing the high temperature resistant thermally conductive epoxy potting material provided by the embodiment of the present invention through a specific implementation example.

[0100] Implementation Example 1:

[0101] This implementation example provides a method for preparing a high-temperature resistant thermally conductive epoxy potting material, requiring that the prepared high-temperature resistant thermally conductive epoxy potting material has high-temperature resistance and its operating temperature can reach 180°C, thermal conductivity, good toughness, good mechanical strength, and can be used for a long time at (-55)°C to 180°C, and can be used for the packaging of windings and power devices.

[0102] In order to ensure that the performance of the high temperature resistant thermal conductive epoxy resin potting material meets the above requirements, this implementation example adopts the following technical solutions:

[0103] First, the components of the potting material prepared in the implementation example are divided into two components A and B, wherein component A (mass ratio) includes: epoxy resin: toughening agent: thermal conductive filler = 100: 15-30: 400-550; component B (mass ratio) includes: curing agent: accelerator = 100: 0.6-0.8.

[0104] The ratio (mass ratio) of component A to component B is 100:100-110.

[0105] The epoxy resins are phenolic epoxy resins and low-viscosity epoxy resins;

[0106] The phenolic epoxy resin is selected from one or both of F-51 and F-54 phenolic epoxy resins.

[0107] The low viscosity epoxy resin is selected from one or both of TDE-85 and CER170.

[0108] The curing agent is a liquid anhydride curing agent. The liquid anhydrides that can be selected include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride and dodecenylsuccinic anhydride. The curing agent can be one or more of them.

[0109] The toughening agent is selected from one or more of polyether polyurethane, hydroxyl-terminated liquid polybutadiene rubber, and carboxyl-terminated liquid polybutadiene rubber.

[0110] The thermal conductive filler is selected from one or more of alumina powder, nano-aluminum nitride powder, boron nitride powder, and silicon carbide powder, and the filler particle size is (400-600) mesh. The thermal conductive filler used needs to be activated.

[0111] The accelerator is selected from one or more of 2-ethyl, 4-methylimidazole, benzene ring modified imidazole, melamine modified imidazole and triisocyanate modified imidazole.

[0112] The preparation method of the above-mentioned coolant-resistant epoxy resin potting material provided by the present invention comprises the following steps:

[0113] Step 1, keeping the phenolic epoxy resin and the low-viscosity epoxy resin at (60-80)° C. for 1 hour to reduce their viscosity;

[0114] Step 2, alumina powder and nano aluminum nitride powder of different particle sizes are mixed in a ratio of 100:7, and then KH550 silane coupling agent and acetone are added, the addition amount of KH550 silane coupling agent is 5% of the mass fraction of the thermal conductive filler, and the addition amount of acetone is 100ml / 100g, and then the thermal conductive filler, coupling agent, acetone, toughening agent and epoxy resin are mixed according to the ratio, and stirred at a speed of 5000 rpm for 30 minutes with a high-speed disperser, and then the mixed filler and resin are placed in a vacuum oven with a vacuum degree of 0.009MPa at 80°C for 1 hour to obtain component A.

[0115] In this step, the addition of acetone allows the coupling agent to fully contact the filler, improves the fluidity of component A during preparation, ensures that the filler and the epoxy resin are evenly mixed, and ensures that the components of the potting material are uniform and stable. In addition, since acetone has a low boiling point (56.5°C) and is volatile, it can be quickly separated from component A by vacuuming and heating during the preparation of component A, without affecting the performance of the potting material.

[0116] Step 3, mixing the curing agent and the accelerator in proportion and stirring evenly to obtain component B.

[0117] Step 4, mix component A and component B in proportion, and put them into a vacuum oven with a vacuum degree of 0.009 MPa at (65±5)° C. for 1 hour to ensure that the acetone is completely volatilized.

[0118] Step 5: Clean the product to be potted and preheat it at (100±2)℃ for about 1 hour, then cool it to 80±2℃ and inject the potting material into the product.

[0119] Step 6, baking and curing: (100±5)℃ / 2h+(150±5)℃ / 2h+(180±5)℃ / 3h.

[0120] Step 7: After curing is completed, the product is naturally cooled to room temperature along with the oven before being taken out.

[0121] The coolant-resistant epoxy resin potting material prepared in the embodiment of the present invention can be used for potting electronic components, windings, etc., and is particularly suitable for potting electrical products with an ambient temperature of (-55)°C to 180°C.

[0122] Implementation Example 2:

[0123] According to the working conditions of the potting material, the performance assessment of the potting material mainly examines thermal conductivity, impact strength, resistance to cold and hot shocks and insulation resistance.

[0124] 1. Thermal conductivity test: Use the Ante 2022 thermal conductivity tester and static method to test the thermal conductivity.

[0125] 2. Impact strength is measured and calculated according to GB / T 1843-2008.

[0126] 3. Thermal shock resistance The Navy Hex rod method was used to test thermal shock resistance, with -55°C, 10 minutes, 120°C, 10 minutes as one cycle, and a total of 10 cycles were performed to observe whether the surface of the sample was cracked.

[0127] 4. Insulation resistance test: in accordance with GB / T 15022.2-2007 "Resin-based active composites for electrical insulation Part 2: Test methods" 5.6.1.

[0128] 5. Electrical strength: in accordance with 5.6.3 of GB / T 15022.2-2007 “Resin-based active composites for electrical insulation Part 2: Test methods”.

[0129] Table 1 Ratio of raw materials

[0130]

[0131] Table 2 Performance of coolant resistant epoxy potting material

[0132]

[0133]

[0134] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A high temperature resistant thermal conductive epoxy potting material, characterized in that: The components of the high temperature resistant thermal conductive epoxy potting material include, by mass: Based on the mass percentage of epoxy resin, 100 mass percentages of epoxy resin; 100-110 parts by mass of a curing agent; 0.6-0.8 mass parts of accelerator; 400-550 parts by mass of thermally conductive filler; 15 to 30 parts by weight of a toughening agent; The epoxy resin is selected from at least one of a phenolic epoxy resin and a low-viscosity epoxy resin; the low-viscosity epoxy resin is selected from at least one of a low-viscosity cyclopentyl glycidyl ester trifunctional epoxy resin and a low-viscosity cyclopentyl glycidyl ether epoxy resin; The thermal conductive filler is selected from at least one of the following: aluminum oxide, aluminum nitride, boron nitride and magnesium oxide.

2. The high temperature resistant thermally conductive epoxy potting material according to claim 1, characterized in that: In the epoxy resin, the phenolic epoxy resin has a large number of rigid groups and a large cross-linking density, so that the use temperature of the prepared thermal conductive epoxy potting material is at least greater than 150°; Based on the requirements for fluidity of high temperature resistant thermal conductive epoxy potting materials in the preparation process, F-51 and F-54 brands of phenolic epoxy resin are selected, TDE-85 brand of low viscosity cyclic glycidyl ester type trifunctional epoxy resin is selected, and CER-170 brand of low viscosity cyclic glycidyl ether is selected.

3. The high temperature resistant thermally conductive epoxy potting material according to claim 1, characterized in that: The epoxy resin curing agent includes at least one of the following: an amine curing agent, an acid anhydride curing agent, and an imidazole curing agent; Wherein, the amine curing agent includes: one of dicyandiamide, m-phenylenediamine, 4,4'-diaminodiphenyl sulfone, and diphenylmethane; The anhydride curing agent is selected from at least one of the following: liquid anhydride of methyl tetracyanophthalic anhydride and methyl nadic anhydride, which is used to prepare a fluid thermal conductive epoxy potting material; wherein the kinematic viscosity of the high temperature resistant thermal conductive epoxy potting material is 1000-5000cps; The imidazole curing agent is used to cure epoxy resin alone, or as an accelerator for a selected curing agent.

4. The high temperature resistant thermally conductive epoxy potting material according to claim 3, characterized in that: When the imidazole curing agent is used as the curing agent, at least one of 2-ethyl and 4-methylimidazole is selected; When the imidazole curing agent is used as an accelerator, at least one of 2-ethyl, 4-methylimidazole, benzene ring modified imidazole, melamine modified imidazole and triisocyanate modified imidazole is selected.

5. The high temperature resistant thermally conductive epoxy potting material according to claim 1, characterized in that: The selection principles of the thermal conductive filler include: Based on the uniformity, isotropy and potting application requirements of the prepared thermally conductive epoxy potting material, it is required to select a thermally conductive filler with insulating properties; Based on the principle of safety, non-toxic thermal conductive fillers are selected.

6. The high temperature resistant thermally conductive epoxy potting material according to claim 1, characterized in that: The toughening agent can be selected from at least one of epoxy toughening agents and non-epoxy toughening agents; Among them, for epoxy toughening agents, Qishi toughening agent is selected as the toughening agent for epoxy resin; As for the non-epoxy toughening agent, at least one of polyether polyurethane, hydroxyl-terminated liquid polybutadiene rubber and carboxyl-terminated liquid polybutadiene rubber is selected as the toughening material for the epoxy resin.

7. A method for preparing a high temperature resistant thermally conductive epoxy potting material, characterized in that: Used to prepare a high temperature resistant thermal conductive epoxy potting material as claimed in any one of claims 1 to 6, comprising: Step 1, selecting materials for each group used to prepare high temperature resistant thermal conductive epoxy potting material; Step 2, dividing the components into component A and component B; Step 3, preparing component A and component B respectively; Step 4, mix component A and component B in proportion, and put them into a vacuum oven with a vacuum degree of 0.009 MPa at (65±5)° C. for 1 hour to ensure that the acetone is completely volatilized; Step 5, clean the product to be potted and preheat it at (100±2)℃ for about 1 hour, then cool it down to 80±2℃ and inject the potting material into the product; Step 6, baking and curing: (100±5)℃ / 2h+(150±5)℃ / 2h+(180±5)℃ / 3h; Step 7: After curing is completed, the product is naturally cooled down to room temperature along with the oven and then taken out; The mass ratio of each component in component A is: epoxy resin: toughening agent: thermal conductive filler = 100: 15-30: 400-550; the mass ratio of each component in component B is: curing agent: accelerator = 100: 0.6-0.8; The mass ratio of component A to component B is 100:100-110.

8. The method for preparing the high temperature resistant thermal conductive epoxy potting material according to claim 7, characterized in that: The preparation method of component A in step 3 comprises: Step 31, keeping the phenolic epoxy resin and the low-viscosity epoxy resin at (60-80)° C. for 1 hour to reduce their viscosity; Step 32, alumina powder and nano aluminum nitride powder of different particle sizes are mixed in a ratio of 100:7, and then KH550 silane coupling agent and acetone are added, the addition amount of KH550 silane coupling agent is 5% of the mass fraction of the thermal conductive filler, and the addition amount of acetone is 100ml / 100g, and then the thermal conductive filler, coupling agent, acetone, toughening agent and epoxy resin are mixed according to the ratio, and stirred at a speed of 5000 rpm for 30 minutes with a high-speed disperser, and then the mixed filler and resin are placed in a vacuum oven with a vacuum degree of 0.009MPa at 80°C for 1 hour to obtain component A.

9. The method for preparing the high temperature resistant thermal conductive epoxy potting material according to claim 7, characterized in that: The preparation method of component B in step 3 is: Step 33, mix the curing agent and the accelerator according to a certain proportion, and stir them evenly to obtain component B.

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