High-thermal-conductivity epoxy resin composition and use thereof in to-220f packages

Abstract

The present invention relates to the technical field of electronic packaging materials, and in particular to a high-thermal-conductivity epoxy resin composition and a use thereof in TO-220F packages. The raw materials of the epoxy resin composition comprise in percentage by weight: 1-10% of an epoxy resin, 3-10% of a phenolic resin, 0.02-4% of a curing accelerator, 0-8% of an additive, and the balance of an inorganic filler. The inorganic filler comprises at least spherical crystalline silicon dioxide. The thermal conductivity of the epoxy resin composition is 2.0 W / m·K or more. In the present invention, by adding the spherical crystalline silicon dioxide to an epoxy molding compound, an electronic component packaging material of the present invention exhibits excellent thermal conductivity. The improvement not only meets the heat dissipation requirements in high-power application scenarios, but also effectively prolongs the service life of electronic components and reduces the failure rate caused by overheating. The obtained product can meet the use requirements of TO-220F packages.

Description

High thermal conductivity epoxy resin composition and its application in TO-220F packaging Technical Field

[0001] This invention relates to the field of electronic packaging materials technology, and in particular to a high thermal conductivity epoxy resin composition and its application in TO-220F packaging. Background Technology

[0002] In recent years, with the rapid advancement of technology and the increasing demand for high-performance, high-reliability electronic components across various industries, fully encapsulated electronic components (such as the TO-220F and TO-3PF series) have gained widespread recognition and application in numerous fields due to their superior electrical insulation properties. Especially in industries such as automotive manufacturing, industrial automation control, and high-end consumer product design, these components, with their excellent packaging technology and stable operating performance, have become key factors in improving the overall performance and lifespan of products.

[0003] However, with the continuous deepening and expansion of technological applications, especially in applications involving high power density, high efficiency conversion, and harsh operating environments, the limitations of traditional epoxy encapsulation materials in terms of thermal conductivity have gradually become apparent. In these scenarios, effectively managing and efficiently dissipating heat to ensure the continuous and stable operation of electronic components without performance degradation or damage due to overheating has become a pressing technical challenge. Therefore, the industry has proposed more stringent thermal conductivity requirements for epoxy encapsulation materials used in fully encapsulated electronic components.

[0004] Chinese patent application CN118240515A discloses a resin composition for electronic packaging. The modified resin with a specific structure effectively reduces the stress of the entire system. Combined with a suitable stress-relieving agent, it not only significantly reduces the modulus and stress level of the entire resin composition but also has minimal impact on water absorption, Tg, and adhesion. The resin composition maintains ultra-low stress at both high and low temperatures, without cracking, delamination, or other failures. Chinese patent application CN110066491A discloses an epoxy resin composition, its preparation method, and its uses. It uses silica A, silica B, and silica C as crystalline silica, and silica D as molten silica. The resulting epoxy resin composition has advantages such as strong applicability, low cost, low water absorption, high fluidity, and high reliability. After encapsulation, the product exhibits characteristics such as no pore defects, no delamination, and good filling, improving the yield of rectifier bridge type component packaging. Chinese patent CN114685938A discloses an epoxy resin composition for electronic packaging and its preparation method. The filler selected includes spherical alumina and crystalline silicon dioxide to improve the thermal conductivity of the material. However, alumina is expensive and has high implementation costs, making it unsuitable for TO-220F packaging.

[0005] However, these existing technologies have not effectively improved the thermal conductivity of epoxy resin molding compounds. There is an urgent need to provide an epoxy resin product with high thermal conductivity that can meet the requirements of TO-220F encapsulation. Summary of the Invention

[0006] To address the technical problem that existing epoxy molding compounds have limited thermal conductivity while TO-220F encapsulation requires high thermal conductivity materials, resulting in a mismatch between the two, the first aspect of this invention provides a high thermal conductivity epoxy resin composition. The epoxy resin composition, by weight percentage, comprises: 1-10% epoxy resin, 3-10% phenolic resin, 0.02-4% curing accelerator, 0-8% additives, and the remainder being inorganic fillers.

[0007] Preferably, the inorganic filler comprises at least spherical crystalline silica.

[0008] More preferably, the mass ratio of the epoxy resin to the inorganic filler is (2-10):(75-90).

[0009] Preferably, the particle size D50 of the spherical crystalline silica is 15-40 μm; more preferably, it is 20 μm.

[0010] Preferably, the maximum particle size of the spherical crystalline silica is 50-90 μm; more preferably, it is 75 μm.

[0011] Preferably, the amount of spherical crystalline silica added to the epoxy resin composition is 40-90 wt%; more preferably, it is 70-88 wt%.

[0012] This invention introduces spherical crystalline silica into an epoxy resin composition, significantly improving the material's thermal conductivity. It is speculated that the unique crystal structure of the spherical crystalline silica allows for efficient heat transfer within the material, thus significantly increasing the overall thermal conductivity of the encapsulation material. When this high thermal conductivity filler is uniformly dispersed in the epoxy encapsulation material, it forms a highly efficient thermally conductive network, enabling rapid heat transfer from the component's interior to the external environment. Further limiting the particle size (D50) of the spherical crystalline silica to 15-40 μm and the maximum particle size to 50-90 μm improves the microstructure of the epoxy encapsulation material. During the filling process, these tiny spherical particles fill the voids in the material, reducing thermal resistance and further improving thermal conductivity. Simultaneously, their presence also inhibits stress accumulation within the material, improving the processing performance of the epoxy resin composition.

[0013] Preferably, the inorganic filler may further include conventional crystalline silica, wherein the mass ratio of conventional crystalline silica to spherical crystalline silica is (1.2-2):1.

[0014] Note: The main difference between conventional crystalline silica and spherical crystalline silica in this invention is that conventional crystalline silica has sharp edges, while spherical crystalline silica is processed and polished by physical means to remove the sharp edges.

[0015] More preferably, the particle size D50 value of the conventional crystalline silica is 15-40 μm; even more preferably, it is 25-35 μm.

[0016] More preferably, the maximum particle size of the conventional crystalline silica is 100-240 μm; even more preferably, it is 160-200 μm.

[0017] The conventional crystalline silica and spherical crystalline silica mentioned are commercially available, such as those from Jiangsu Lianrui New Materials Co., Ltd.

[0018] Preferably, the epoxy resin has a structural formula that is a combination of one or more compounds as shown in Formula I and Formula II;

[0019] Formula I: Where n is selected from 1, 2, or 3;

[0020] Formula II: Where m is selected from 1, 2 or 3.

[0021] The compounds shown in Formula I and Formula II are all commercially available, including but not limited to the following sources.

[0022] Formula I: Supplier: Changchun Artificial Resin Factory, Product Model: CNE-195LL.

[0023] Formula II: Supplier: DIC Epoxy (Malaysia) Sdn. Bhd., Product Model: HP-7200.

[0024] More preferably, the epoxy resin includes at least the compound shown in Formula II, wherein the compound shown in Formula II is added to the epoxy resin composition in an amount of 2-6.5 wt%.

[0025] More preferably, the epoxy resin comprises a compound of compounds shown in Formula I and Formula II.

[0026] Preferably, the compound shown in Formula I is added to the epoxy resin composition in an amount of 1-7 wt%.

[0027] Preferably, the structural formula of the phenolic resin is: Where x is selected from 1, 2 or 3.

[0028] The phenolic resin can be commercially available, including but not limited to: Shandong Shengquan New Material Co., Ltd., product model PF8013. This invention preferably uses a high-viscosity phenolic resin to meet the processing requirements of TO-220F, avoiding porosity problems during part processing.

[0029] Preferably, the amount of phenolic resin added to the epoxy resin composition is 4-7 wt%.

[0030] The present invention selects epoxy resin and phenolic resin with specific structures, which can be well matched with silica fillers with specific morphology and particle size, so that the thermal conductivity of the final epoxy resin composition is increased to more than 2.0 W / m·K.

[0031] The curing accelerator may include triphenylphosphine-benzoquinone adduct, triphenylphosphine, imidazole compounds, etc.; preferably, the curing accelerator includes at least one of triphenylphosphine-benzoquinone adduct and triphenylphosphine; more preferably, the curing accelerator includes triphenylphosphine-benzoquinone adduct.

[0032] This invention allows for flexible selection of additives based on downstream packaging requirements. Examples of additives include coupling agents, colorants, release agents, toughening agents, stress modifiers, flame retardants, lubricants, antistatic agents, and UV absorbers.

[0033] Preferably, the additive includes at least one of a coupling agent, a colorant, and a release agent; the amount of the additive added to the epoxy resin composition is 0.1-3 wt%.

[0034] To further balance the high thermal conductivity and processing performance of the epoxy resin composition, more preferably, the additives include coupling agents, colorants and release agents in a mass ratio of 1:(1-1.5):(1.4-2).

[0035] Preferably, the coupling agent comprises one or more of 3-(glycidoxypropyl)trimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

[0036] More preferably, the coupling agent comprises one or more combinations of 3-(glycidyloxypropyl)trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

[0037] More preferably, the coupling agent comprises 3-(glycidyloxypropyl)trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane in a weight ratio of 1:1:1.

[0038] The release agent may be listed as a natural wax or a synthetic wax.

[0039] Preferably, the natural wax includes one or more of carnauba wax, candelilla wax, wood wax, beeswax, paraffin wax, and their derivatives.

[0040] Preferably, the synthetic wax includes one or more combinations of polyethylene wax, polypropylene wax, polyester wax, and polyurethane wax.

[0041] More preferably, the release agent comprises natural wax, and more preferably carnauba wax.

[0042] In some embodiments, the pigment may be exemplified as carbon black.

[0043] In some preferred embodiments, the epoxy resin composition has a thermal conductivity of 2.0 W / m·K or higher.

[0044] More preferably, the epoxy resin composition satisfies one or more of the following conditions a to c:

[0045] a. Thermal conductivity is 2.2-2.5 W / m·K;

[0046] b. The gelation time is 20-40 seconds, and the test conditions are 175℃;

[0047] c. The spiral flow length is 10-20 inches, and the test conditions are curing at 175°C for 90 seconds.

[0048] More preferably, the epoxy resin composition simultaneously satisfies conditions a to c.

[0049] A second aspect of the present invention provides a method for preparing a high thermal conductivity epoxy resin composition, wherein the preparation steps of the epoxy resin composition include:

[0050] 1) Pulverize the epoxy resin and phenolic resin separately, package and seal the powders for later use;

[0051] 2) Mix all raw materials except epoxy resin and phenolic resin, add the pulverized epoxy resin and phenolic resin, and mix evenly;

[0052] 3) The material obtained in step 2) is compounded, extruded, and cooled to obtain an epoxy resin composition product.

[0053] In some preferred embodiments, the preparation steps of the epoxy resin composition include:

[0054] 1) Epoxy resin and phenolic resin were pulverized separately under low temperature conditions, and the powders were packaged, sealed, and stored at low temperature for later use.

[0055] 2) Under low temperature conditions, inorganic fillers, curing accelerators and additives are added to a high-speed mixer in batches and mixed. Then, pulverized epoxy resin and phenolic resin are added and mixed evenly.

[0056] 3) Transfer the material obtained in step 2) to an extruder for mixing and extrusion, cool and then crush to obtain an epoxy resin composition product.

[0057] Preferably, step 1) involves pulverizing the resin using a resin pulverizer.

[0058] Preferably, the low temperature conditions in steps 1) and 2) are both below 25°C, more preferably 10-20°C, and most preferably 15°C.

[0059] In some embodiments, the extruder includes a single-screw extruder or a twin-screw extruder; preferably, the extruder is a twin-screw extruder.

[0060] Preferably, the extrusion temperature is 90-120°C, more preferably 95-105°C.

[0061] Preferably, the epoxy resin composition product is stored in a sealed environment at a low temperature below 5°C.

[0062] A third aspect of the present invention provides an application of a high thermal conductivity epoxy resin composition, which is used in the field of electronic packaging, and is particularly suitable for TO-220F packaging.

[0063] The TO-220F package is a through-hole package designed for high-power transistors and small-to-medium scale integrated circuits. The metal tab (heat sink) of the TO-220F package is in close contact with the internal structure of the device, effectively transferring internally generated heat to the external environment. This design allows the device to maintain a lower operating temperature in high-power applications, thereby improving its stability and reliability. However, the current TO-220F package still lags behind the TO-220AC package in terms of heat dissipation performance. This invention, by adding spherical crystalline silicon dioxide to the epoxy molding compound, endows the packaging material with superior thermal conductivity. This improvement not only meets the heat dissipation requirements of high-power applications but also effectively extends the lifespan of electronic components and reduces the failure rate caused by overheating, showing broad application prospects. Beneficial effects:

[0064] This invention provides a high thermal conductivity epoxy resin composition, its preparation method, and its application in TO-220F packaging, which has the following advantages:

[0065] (1) Improved thermal conductivity: By adding spherical crystalline silicon dioxide to the epoxy encapsulation material, the electronic component packaging material of the present invention exhibits excellent thermal conductivity. This improvement not only meets the heat dissipation requirements in high-power application scenarios, but also effectively extends the service life of electronic components and reduces the failure rate caused by overheating.

[0066] (2) Optimized material structure: This invention optimizes the internal structure of epoxy encapsulation materials by precisely controlling the amount and dispersion of spherical crystalline silica. This optimization enables the material to maintain high thermal conductivity while also possessing good mechanical and processing properties, providing greater convenience for the manufacturing and packaging of electronic components.

[0067] (3) Improved production efficiency: Due to the excellent flowability and moldability of epoxy molding compounds with added spherical crystalline silica, the packaging efficiency of electronic components can be significantly improved in actual production. This not only reduces production costs but also shortens the product production cycle, resulting in positive economic benefits.

[0068] (4) Expanding Application Areas: Due to its excellent thermal conductivity and insulation properties, the electronic component packaging material of this invention has shown broad application prospects in various fields such as automobiles, industry, and consumer goods. It is particularly suitable for high-power, high-heat-dissipation scenarios such as TO-220F packaging, where this material will play an even more important role and promote the rapid development of related industries.

[0069] (5) Meets mass production requirements: This invention uses specific epoxy resin, phenolic resin and spherical crystalline silica as raw materials to significantly improve the thermal conductivity of the material; the raw materials are readily available and the formula is simple, the process is simple and the operation is simple, which can meet the requirements of mass production. Detailed Implementation

[0070] Note: Unless otherwise specified, all raw materials used in this invention are commercially available.

[0071] Example

[0072] Examples 1-3

[0073] Examples 1-3 respectively provide a high thermal conductivity epoxy resin composition, its preparation method, and its application in TO-220F encapsulation.

[0074] The formulation of the epoxy resin composition is shown in Table 1; the values ​​in Table 1 are the amount of raw materials added, and the unit is weight percentage.

[0075] Table 1 Formulations of the epoxy resin compositions in Examples 1-3

[0076] Note: In Table 1, / represents not added.

[0077] The sources of the raw materials in Table 1 are as follows.

[0078] Formula I: Supplier: Changchun Artificial Resin Factory, Product Model: CNE-195LL.

[0079] Formula II: Supplier: DIC Epoxy (Malaysia) Sdn. Bhd., Product Model: HP-7200.

[0080] Phenolic resin: Shandong Shengquan New Material Co., Ltd., product model PF8013.

[0081] Spherical crystalline silica: maximum particle size 75 μm, particle size D50 value 20 μm, specific surface area 2.5 m². 2 / g; sourced from Jiangsu Lianrui New Materials Co., Ltd.

[0082] Conventional crystalline silica: maximum particle size 180um, particle size D50 value 29um; sourced from Jiangsu Lianrui New Materials Co., Ltd.

[0083] Spherical fused silica: maximum particle size 75µm, particle size D50 value 20µm; sourced from Jiangsu Lianrui New Materials Co., Ltd.

[0084] Triphenylphosphine-benzoquinone adduct: specifically triphenylphosphine-1,4-benzoquinone adduct, CAS number 5405-63-0.

[0085] Brazilian carnauba wax: Supplier: NIKKO FINE Co., Ltd., product model: Nikko carnauba.

[0086] Carbon black: Supplier: Mitsubishi Chemical Corporation, product model MA600.

[0087] The preparation steps of the epoxy resin composition include:

[0088] 1) Use a resin pulverizer to pulverize epoxy resin and phenolic resin separately, and control the operating temperature at 15℃; then package and seal them, and store them at low temperature for later use.

[0089] 2) Add the inorganic filler, curing accelerator, coupling agent, release agent and color powder to the high-speed mixer in batches and mix them. The operating temperature is controlled at 15℃. Then add the crushed epoxy resin and phenolic resin and mix them evenly.

[0090] 3) Transfer the material obtained in step 2) to a twin-screw extruder, mix and extrude at 100°C, cool and then pulverize to obtain the epoxy resin composition product.

[0091] The resulting epoxy resin composition should be stored at a low temperature (below 5°C) for later use.

[0092] Performance testing methods

[0093] Referring to the method of GB / T 40564-2021, the gelation time, spiral flow length and thermal conductivity of the epoxy resin compositions prepared in Examples 1-3 were tested, and the test results are shown in Table 2.

[0094] The test conditions for spiral flow length were curing at 175℃ for 90 seconds and gelation time were also tested at 175℃.

[0095] Performance test results

[0096] The test results of the epoxy resin compositions obtained in Examples 1-3 are shown in Table 2.

[0097] Table 2 Performance test results of the epoxy resin compositions in Examples 1-3

[0098] As shown in Table 2, replacing spherical molten silica with spherical crystalline silica in the epoxy resin composition effectively improves the thermal conductivity of the epoxy molding compound. Selecting an addition amount of 86% spherical crystalline silica further enhances the material's thermal conductivity while maintaining suitable gelation time and spiral flow length. The epoxy resin compositions obtained in Examples 2 and 3 of this invention exhibit higher thermal conductivity than most similar products from the same industry, meeting the requirements for TO-220F encapsulation.

Claims

1. A high thermal conductivity epoxy resin composition, characterized in that, The raw materials of the epoxy resin composition, by weight percentage, include: 1-10% epoxy resin, 3-10% phenolic resin, 0.02-4% curing accelerator, 0-8% additives, and inorganic fillers to make up the balance. The inorganic filler includes at least spherical crystalline silicon dioxide; The epoxy resin composition has a thermal conductivity of 2.0 W / m·K or higher.

2. The high thermal conductivity epoxy resin composition according to claim 1, characterized in that, The spherical crystalline silica has a particle size D50 value of 15-40 μm and a maximum particle size of 50-90 μm.

3. The high thermal conductivity epoxy resin composition according to claim 2, characterized in that, The amount of spherical crystalline silica added to the epoxy resin composition is 40-90 wt%.

4. The high thermal conductivity epoxy resin composition according to claim 1, characterized in that, The epoxy resin has a structural formula that is a combination of one or more compounds as shown in Formula I and Formula II below; Formula I: Where n is selected from 1, 2, or 3; Formula II: Where m is selected from 1, 2 or 3.

5. The high thermal conductivity epoxy resin composition according to claim 4, characterized in that, The epoxy resin comprises a compound of the compounds shown in Formula I and Formula II.

6. The high thermal conductivity epoxy resin composition according to claim 4, characterized in that, The structural formula of the phenolic resin is: Where x is selected from 1, 2 or 3.

7. The high thermal conductivity epoxy resin composition according to claim 1, characterized in that, The additives include coupling agents, colorants, and release agents in a mass ratio of 1:(1-1.5):(1.4-2); The additive is added to the epoxy resin composition in an amount of 0.5-3 wt%.

8. The high thermal conductivity epoxy resin composition according to claim 7, characterized in that, The epoxy resin composition satisfies one or more of the following conditions a to c: a. Thermal conductivity is 2.2-2.5 W / m·K; b. The gelation time is 20-40 seconds, and the test conditions are 175℃; c. The spiral flow length is 10-20 inches, and the test conditions are curing at 175°C for 90 seconds.

9. A method for preparing a high thermal conductivity epoxy resin composition according to any one of claims 1 to 8, characterized in that, The preparation steps include: 1) Epoxy resin and phenolic resin were pulverized separately under low temperature conditions, and the powders were packaged, sealed, and ready for use. 2) Mix the raw materials except epoxy resin and phenolic resin under low temperature conditions, add the pulverized epoxy resin and phenolic resin, and mix evenly; 3) The material obtained in step 2) is compounded, extruded, and cooled to obtain an epoxy resin composition product; The low-temperature conditions for both steps 1) and 2) are below 25°C.

10. The use of a high thermal conductivity epoxy resin composition according to any one of claims 1 to 8 in TO-220F encapsulation.

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