A high-thermal-conductivity, high-insulation and high-Tg bio-based epoxy composite material, a preparation method and application thereof

Abstract

The present application relates to a kind of high thermal conductivity, high insulation and high Tg biological epoxy composite material and its preparation method and application.The raw material components of the biological epoxy composite material include epoxy vanillin dimer, epoxy vegetable oil, curing agent, modified thermal conductive particle filler and diluent, by using biological epoxy vanillin dimer instead of bisphenol A type epoxy resin, raw material is widely available, green and environmentally friendly, and rigid epoxy vanillin dimer is matched with flexible epoxy vegetable oil, further combined with modified thermal conductive particle filler etc., to prepare biological composite material with high glass transition temperature, excellent thermal conductivity and insulation performance, has wide application prospect in thermal interface material field, especially in the application of third-generation semiconductor high-power inverter.

Description

Technical Field

[0001] This invention belongs to the field of bio-based composite materials, specifically relating to a bio-based epoxy composite material with high thermal conductivity, high insulation and high Tg, its preparation method and application. Background Technology

[0002] Epoxy resins are widely used in various industries due to their excellent mechanical strength, chemical stability, and dimensional stability. Bisphenol A (BPA) type epoxy resins, prepared by glycidylation of bisphenol A and epichlorohydrin, occupy the majority of the market share; E44 and E51 are representative BPA type resins. However, the non-renewable nature of raw materials and the potential health hazards of BPA structure have forced the search for bio-based epoxy resins.

[0003] Bio-based epoxy resins synthesized from vegetable oils, starch, cellulose, and their derivatives have been extensively studied and have made some progress in recent years. However, from the perspective of industrial chain integrity and product application, bio-based epoxy resins currently do not have a price advantage. Developing high-value, multifunctional, and high-performance bio-based epoxy composite materials is therefore of practical significance. For example, Chinese patent document CN116444462A discloses an isovanthanin bio-based epoxy resin monomer, and the resulting bio-based epoxy resin polymer material has a low curing processing temperature and good heat resistance (initial decomposition temperature ~300.8℃). Summary of the Invention

[0004] In view of the shortcomings and problems in the prior art, the present invention aims to provide a high thermal conductivity, high insulation and high Tg bio-based epoxy composite material, its preparation method and application.

[0005] The first objective of this invention is to provide a bio-based epoxy composite material with high thermal conductivity, high insulation, and high Tg, mainly composed of the following raw materials: epoxy vanillin dimer, epoxy vegetable oil, curing agent, modified thermally conductive particle filler, and diluent, wherein the curing agent is a curing agent containing rigid groups, and the structural formula of the epoxy vanillin dimer is as follows:

[0006]

[0007] The present invention utilizes epoxy vanillin dimer, which has a structure similar to that of bisphenol A epoxy resin, and epoxy vegetable oil to react and prepare bio-based epoxy composite materials, avoiding the hazards of bisphenol A epoxy resin and promoting the development of bio-based epoxy resins.

[0008] The epoxy vanillin dimer in this invention is obtained by coupling vanillin to form a dimer, followed by glycidylation. Specifically, vanillin, ferrous sulfate, and sodium persulfate are first used as raw materials to prepare the dimer through a coupling reaction at 80°C; then, the dimer is mixed with epichlorohydrin and TBAB (tetrabutylammonium bromide) at 80°C for polymerization; and finally, sodium hydroxide aqueous solution and TBAB are added at room temperature to carry out a ring-closure reaction. In one specific embodiment, 6 g vanillin (39.5 mmol), 0.2 g FeSO4·7H2O (0.72 mmol), and 5 g Na2S2O8 (21.0 mmol, 0.53 equiv) were mixed in 400 mL of water and stirred at 80 °C for 30 min. After filtration, the precipitate was collected, washed three times with hot water at 80 °C, and dried to obtain vanillin dimer. Then, 4 g vanillin dimer (13.2 mmol), 24.5 g epichlorohydrin (0.265 mol), and 0.4 g TBAB (tetrabutylammonium bromide, 1.2 mmol) were stirred at 80 °C for 2 h. Subsequently, sodium hydroxide aqueous solution (5 M, 10.6 mL) and 0.4 g TBAB (1.2 mmol) were added to the reaction solution at room temperature, and the reaction was continued for 1 h to close the ring. Finally, the solvent was removed by freeze drying, and the product was washed several times with deionized water and dried to obtain epoxy vanillin dimer.

[0009] In some embodiments, the epoxy bio-based composite material raw material components, by weight, include 30-50 parts of epoxy vanillin dimer, 0-20 parts of epoxy vegetable oil, 5-30 parts of curing agent, 10-80 parts of modified thermally conductive particle filler, and 10-30 parts of diluent; preferably, it includes 40-50 parts of epoxy vanillin dimer, 10-20 parts of epoxy vegetable oil, 5-30 parts of curing agent, 10-50 parts of modified thermally conductive particle filler, and 10-30 parts of diluent.

[0010] In some embodiments, the epoxidized vegetable oil is at least one or more of epoxidized soybean oil, epoxidized castor oil, epoxidized tung oil, epoxidized linseed oil, and epoxidized palm oil.

[0011] In some embodiments, the curing agent is at least one or more selected from phenolic epoxy resin curing agents, acid anhydride curing agents, polyamine curing agents, and polyamide curing agents containing rigid groups. For example, it may be a phenolic epoxy resin curing agent; an acid anhydride curing agent, polyamine curing agent, or polyamide curing agent containing a rigid aliphatic ring or benzene ring structure, etc.

[0012] In some embodiments, the diluent is at least one or more of acetone, butanone, toluene, dichloromethane, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0013] In some embodiments, the modified thermally conductive particle packing in this invention is a thermally conductive particle packing modified with a silane coupling agent. Specifically, the thermally conductive particles are added to a silane coupling agent solution for hydrolysis modification, followed by washing and drying.

[0014] In some embodiments, the silane coupling agent is at least one or more of KH-550, KH-560 and KH-580.

[0015] In some embodiments, the thermally conductive particles are at least one or more of boron nitride, aluminum nitride, aluminum oxide, silicon carbide, or synthetic diamond.

[0016] Another object of the present invention is to provide a method for preparing the above-mentioned high thermal conductivity, high insulation and high Tg bio-based epoxy composite material, which, in some embodiments, includes the following steps:

[0017] (1) Weigh out epoxy vanillin dimer, epoxy vegetable oil, curing agent, modified thermally conductive particle filler and diluent; stir and mix evenly and degas to obtain bio-based epoxy resin solution;

[0018] (2) The above-mentioned bio-based epoxy resin solution is poured into a mold and pre-cured at 50-90℃ for 0.5-2 hours to volatilize the diluent. Then, it is cured at 120-160℃ for 12-36 hours to obtain a bio-based epoxy composite material. Specifically, the curing time can be adjusted according to the type and amount of diluent added. For example, it can be pre-cured at 50℃, 60℃, 70℃, 80℃, or 90℃ for 0.5 hours, 1 hour, 1.5 hours, or 2 hours, etc., and then cured at 120℃, 130℃, 140℃, 150℃, or 160℃ for 12 hours, 18 hours, 24 hours, 30 hours, or 36 hours, etc.

[0019] Another object of the present invention is to provide the application of the above-mentioned high thermal conductivity, high insulation and high Tg bio-based epoxy composite material in the field of thermal interface materials.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention uses bio-based epoxy vanillin dimer instead of bisphenol A type epoxy resin. The raw materials are widely available, environmentally friendly, and align with the concept of sustainable development. The rigid epoxy vanillin dimer is combined with flexible epoxy vegetable oil, and further incorporated with modified thermally conductive particle fillers, to prepare a bio-based composite material with a high glass transition temperature, excellent thermal conductivity, and insulation properties. This material has broad application prospects in the field of thermal interface materials, particularly in the application of third-generation semiconductor high-power inverters. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. Preferred embodiments of the invention are shown in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of the present invention will be achieved.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] Unless otherwise specified, all reagents used in the following examples are commercially available; and all methods used in the following examples are conventional methods.

[0025] The structural formulas of the epoxy vanillin dimers used in the following examples and comparative examples are as follows:

[0026] It is obtained by using vanillin as a raw material, which is obtained by coupling reaction to obtain dimer and then further glycidylating.

[0027] Specifically, 6g vanillin (39.5mmol), 0.2g FeSO4·7H2O (0.72mmol) and 5g Na2S2O8 (21.0mmol, 0.53equiv) were mixed in 400mL of water, stirred at 80℃ for 30min, filtered, and the precipitate was collected. The precipitate was washed three times with hot water at 80℃ and then dried to obtain vanillin dimer.

[0028] Then, 4 g of vanillin dimer (13.2 mmol), 24.5 g of epichlorohydrin (0.265 mol), and 0.4 g of TBAB (1.2 mmol) were stirred at 80 °C for 2 h. Subsequently, sodium hydroxide aqueous solution (5 M, 10.6 mL) and 0.4 g of TBAB (1.2 mmol) were added to the reaction solution at room temperature, and the reaction was continued for 1 h to close the ring. Finally, the solvent was removed by freeze drying, and the product was washed several times with deionized water and dried to obtain epoxy vanillin dimer.

[0029] Example 1

[0030] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0031] Step 1: Take 50 parts by weight of epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified boron nitride filler and 20 parts of acetone, mix them evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0032] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0033] Example 2

[0034] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0035] Step 1: Take 50 parts of rigid epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified aluminum nitride filler and 20 parts of acetone according to the weight ratio, stir and mix evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0036] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0037] Example 3

[0038] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0039] Step 1: Take 50 parts of rigid epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified alumina filler and 20 parts of acetone according to the weight ratio. Mix them evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0040] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0041] Example 4

[0042] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0043] Step 1: Take 50 parts of rigid epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified artificial diamond filler and 20 parts of acetone according to the weight ratio. Mix them evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0044] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0045] Example 5

[0046] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0047] Step 1: Take 50 parts of rigid epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified silicon carbide filler and 20 parts of acetone according to the weight ratio. Mix them evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0048] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0049] Comparative Example 1

[0050] An epoxy composite material, the preparation method of which includes the following steps:

[0051] Step 1: Take 50 parts by weight of epoxy E44 resin, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of KH-560 modified boron nitride filler and 20 parts of acetone, mix them evenly with a mixer and degas to obtain an epoxy resin solution.

[0052] Step 2: Pour the above epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain a bio-based epoxy composite material.

[0053] Comparative Example 2

[0054] An epoxy bio-based composite material, the preparation method of which includes the following steps:

[0055] Step 1: Take 50 parts of rigid epoxy vanillin dimer, 10 parts of flexible epoxy castor oil, 30 parts of phenolic modified amine curing agent, 50 parts of unmodified boron nitride filler and 20 parts of acetone according to the weight ratio, stir and mix evenly with a mixer and degas to obtain a bio-based epoxy resin solution.

[0056] Step 2: Pour the above bio-based epoxy resin solution into a mold and pre-cur it at 50°C for 1 hour to evaporate the diluent. Then, cure it at 120°C for 24 hours to obtain the bio-based epoxy composite material.

[0057] Performance testing:

[0058] Thermal conductivity: The thermal diffusivity α,m of the implementation case and the control case was tested using a NETZSCH LFA467 laser scattering thermal conductivity meter from Germany. 2 / s, using the water displacement method and an electronic balance to test the bulk density ρ of the material, g / cm³. 3 According to the formula

[0059] λ=α×ρ×Cp

[0060] Calculate the thermal conductivity λ of the composite material, W / (m·K).

[0061] Insulation strength: The insulation strength of the test cases and comparative cases were determined using the Chroma 19073 tester from Taiwan, China.

[0062] Glass transition temperature: Different samples were studied and analyzed using a TA-Q200 differential scanning calorimeter manufactured by TA Instruments, Inc.

[0063] Mechanical properties: The samples were tested using a UTM 5000 universal testing machine from Shenzhen Sansi Company. Each sample was tested five times according to ASTM D638-03 standard.

[0064] The test results are shown in Table 1.

[0065] Table 1 Performance comparison of the embodiments and comparative examples

[0066]

[0067] As shown in Table 1, the bio-based rigid epoxy vanillin dimer exhibits superior mechanical properties, glass transition temperature, thermal conductivity, and insulation properties compared to traditional petroleum-based bisphenol A epoxy resin. The epoxy vanillin dimer uses a biphenyl structure, and the hydroxyl groups on the benzene ring more readily form intermolecular hydrogen bonds. During curing, the hard segments of the polymer network aggregate, making it easier to form regular molecular chain segments, thus resulting in superior mechanical properties compared to traditional petroleum-based resins. The difference in thermal conductivity is determined by the properties of the thermally conductive particles themselves. Comparing Example 1 and Comparative Example 2, it can be seen that the particles modified with the silane coupling agent KH-560 are more uniformly dispersed in the resin, forming a continuous thermally conductive network after curing. Therefore, the modified thermally conductive particles have better thermal conductivity than the unmodified particles. Furthermore, the more regular molecular chain segments reduce phonon scattering. Therefore, comparing Example 1 and Comparative Example 1, the bio-based epoxy composite material shows significantly improved thermal conductivity, and other properties are also improved.

[0068] In summary, the bio-based epoxy composite material of the present invention, which has high thermal conductivity, high insulation and high Tg, has broad application prospects in thermal interface materials, especially in the field of semiconductor packaging.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high thermal conductivity, high insulation, and high Tg bio-based epoxy composite, characterized in that, The raw material components of the bio-based epoxy composite material include: 30-50 parts of epoxy vanillin dimer, 10-20 parts of epoxy vegetable oil, 5-30 parts of curing agent, 10-80 parts of modified thermally conductive particle filler and 10-30 parts of diluent. The curing agent is a curing agent containing rigid groups; The structural formula of the epoxy vanillin dimer is as follows: ； The epoxidized vegetable oil is at least one or more of epoxidized soybean oil, epoxidized castor oil, epoxidized tung oil, epoxidized linseed oil, and epoxidized palm oil; The modified thermally conductive particle packing is a thermally conductive particle packing modified with a silane coupling agent.

2. The bio-based epoxy composite material according to claim 1, characterized in that, The curing agent is at least one or more of the following: phenolic epoxy resin curing agents, acid anhydride curing agents, polyamine curing agents, and polyamide curing agents containing rigid groups.

3. The bio-based epoxy composite of claim 1, wherein, The diluent is at least one or more of acetone, butanone, toluene, dichloromethane, N,N-dimethylformamide, and N,N-dimethylacetamide.

4. The bio-based epoxy composite material according to claim 1, characterized in that, The silane coupling agent is at least one or more of KH-550, KH-560 and KH-580.

5. The bio-based epoxy composite material according to claim 1, characterized in that, The thermally conductive particles are at least one or more of boron nitride, aluminum nitride, aluminum oxide, silicon carbide, or synthetic diamond.

6. A method for preparing a high thermal conductivity, high insulation, and high Tg bio-based epoxy composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Weigh the epoxy vanillin dimer, epoxy vegetable oil, curing agent, modified thermally conductive particle filler and diluent; stir and mix evenly and degas to obtain a bio-based epoxy resin solution; (2) The above bio-based epoxy resin solution is poured into a mold and pre-cured at 50-90℃ for 0.5-2h to volatilize the diluent, and then cured at 120-160℃ for 12-36h to obtain the bio-based epoxy composite material.

7. The application of the high thermal conductivity, high insulation and high Tg bio-based epoxy composite material according to any one of claims 1-5 in the field of thermal interface materials.

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