Composite material as well as preparation method and application thereof

Abstract

The invention discloses a composite material as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The composite material comprises the following components in parts by weight: 10-50 parts of epoxy resin; 10-20 parts of vegetable oleic acid; 1-3 parts of sulfur; 70-90 parts of a modified heat-conducting filler; the modified heat-conducting filler is obtained by modifying a heat-conducting filler through a double-bond-terminated silane coupling agent; the vegetable oleic acid comprises at least one of eleostearic acid, linolenic acid, linoleic acid, soybean oleic acid, oleic acid, ricinoleic acid and undecylenic acid. The composite material disclosed by the invention not only has the characteristics of high thermal conductivity and excellent electrical insulation performance, but also has good hot working performance and recycling capability, and shows a wide application prospect in the fields of high-thermal-conductivity green electronic packaging materials, electrical insulation coatings and sustainable composite materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, and in particular to a composite material and a preparation method and application thereof. BACKGROUND

[0002] At present, electronic devices are increasingly developing towards high integration and high power density, which puts forward higher requirements for thermal management materials. Not only should the thermal management materials have excellent thermal conductivity and insulation performance, but also should meet key indicators such as sustainability, green environmental protection and recyclability. Traditional thermal interface materials are mainly based on petroleum-based epoxy resin, which is combined with inorganic thermal conductive fillers. Although the traditional thermal interface materials have certain performance, they have defects such as large interfacial thermal resistance, high brittleness, non-renewable resources and the like, and are difficult to adapt to the development trend of green manufacturing. SUMMARY

[0003] The present application aims to overcome the deficiencies of the prior art and provides a composite material and a preparation method and application thereof. The composite material has the characteristics of high thermal conductivity and excellent electrical insulation performance, and also has good thermal processing performance and recyclability, and has broad application prospects in the fields of high-thermal-conductivity green electronic packaging materials, electrical insulation coatings and sustainable composite materials.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0005] In a first aspect, the present application provides a composite material comprising the following components by weight:

[0006] epoxy resin 10-50 parts; vegetable fatty acid 10-20 parts; sulfur 1-3 parts; modified thermal conductive filler 70-90 parts; the modified thermal conductive filler is obtained by modifying the thermal conductive filler with end double bond silane coupling agent;

[0007] The vegetable fatty acid includes at least one of tung oil acid, linolenic acid, linoleic acid, soybean oil acid, oleic acid, ricinoleic acid and undecylenic acid.

[0008] In the present application, the double bond in the molecule of vegetable oil acid reacts with sulfur under the action of heat to generate a dynamic polysulfide bond network, so that the polymer has certain reversible reconstruction ability while meeting the mechanical and thermal properties, realizing thermal processing recovery. The three-dimensional cross-linked structure of epoxy resin provides overall mechanical stability, and the high polarization of sulfur element enhances the electrical insulation properties of the system. More importantly, after the surface modification of the double bond silane coupling agent, the heat-conducting filler can be covalently grafted by participating in the reverse vulcanization reaction of sulfur, significantly enhancing the interfacial bonding force between the filler and the matrix and reducing the interfacial thermal resistance, thereby forming a stable and efficient heat conduction path. Therefore, the present application constructs a multi-dimensional heat conduction channel through the reverse vulcanization cross-linking strategy, while realizing the reversible regulation of the network structure of the material, so that the composite material has excellent thermal conductivity, electrical insulation performance, thermal processing performance and recyclable ability.

[0009] Preferably, the D50 particle size of the heat-conducting filler is 30-120 μm.

[0010] Preferably, the modification method of the modified heat-conducting filler is: stirring the dried heat-conducting filler in an ethanol solution containing a terminal double bond silane coupling agent, and then drying.

[0011] Preferably, the mass of the terminal double bond silane coupling agent is 1-2% of the mass of the heat-conducting filler.

[0012] Preferably, the epoxy resin includes at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic type epoxy resin, and alicyclic epoxy resin.

[0013] More preferably, the epoxy resin includes bisphenol S type epoxy resin and phenolic type epoxy resin, and the weight ratio of the bisphenol S type epoxy resin and the phenolic type epoxy resin is (70-90):(10-30).

[0014] The present application is advantageous in improving the heat resistance and Tg of the composite material by compounding two kinds of epoxy resins with different properties.

[0015] Preferably, the heat-conducting filler includes at least one of boron nitride, aluminum nitride, aluminum oxide, diamond, and aluminum hydroxide.

[0016] Preferably, the terminal double bond silane coupling agent includes at least one of 3-methacryloyloxypropyl trimethoxysilane, allyl trimethoxysilane, and vinyl triethoxysilane.

[0017] Preferably, the composite material includes the following components by weight:

[0018] Epoxy resin 10-30 parts; vegetable oil acid 10-15 parts; sulfur 1-3 parts; modified heat-conducting filler 75-85 parts.

[0019] In a second aspect, the present application further provides a method for preparing a composite material, comprising the following steps:

[0020] Mixing the epoxy resin, the vegetable acid, the sulfur and the modified thermal conductive filler to obtain a mixture; and then hot-pressing the mixture to obtain the composite material.

[0021] Preferably, the hot-pressing temperature is 170-180℃, and the hot-pressing time is 2-6h.

[0022] In a third aspect, the present application further provides an application of the composite material in green electronic packaging material, electrical insulation coating and sustainable composite material.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] (1) In the present application, the raw material is the vegetable acid from a biological source, which replaces the traditional petroleum-based curing agent and meets the concept of green environmental protection.

[0025] (2) In the present application, the raw material introduces the petroleum by-product sulfur, which not only realizes the high-value utilization of sulfur, but also plays a role in toughening and cross-linking the thermal conductive powder.

[0026] (3) The material of the present application obtains a network through reverse vulcanization reaction and epoxy-carboxylic acid reaction mode, which not only solves the problems of difficult dispersion and easy agglomeration of the thermal conductive filler, but also obtains the characteristics of recyclable and reworkable of the polymer network through the reverse vulcanization of the disulfide bond. DETAILED DESCRIPTION

[0027] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples, but the protection scope and implementation mode of the present application are not limited thereto.

[0028] In the following examples, the materials and reagents used, unless otherwise specified, are commercially available reagents and materials.

[0029] Example 1

[0030] The present embodiment discloses a composite material, which comprises the following components by weight:

[0031] Epoxy resin 10 parts; vegetable acid 10 parts; sulfur 2 parts; modified thermal conductive filler 80 parts. Among them, the epoxy resin is bisphenol A type epoxy resin (Balin Petrochemical, E44 type), the vegetable acid is undecylenic acid, and the thermal conductive filler is aluminum nitride.

[0032] The modification method of the modified heat-conductive filler is as follows: the heat-conductive filler is added into an ethanol solution containing a terminal double bond silane coupling agent (the mass concentration of the terminal double bond silane coupling agent in the ethanol solution is 5 wt%), after heating and stirring at 60°C for 8 hours, the modified heat-conductive filler is obtained by filtering and drying. The terminal double bond silane coupling agent is 3-methacryloyloxypropyl trimethoxysilane, and the mass of the terminal double bond silane coupling agent is 1% of the mass of the heat-conductive filler.

[0033] The modification principle is as follows:

[0034]

[0035] The embodiment also discloses a preparation method of the composite material, which comprises the following steps:

[0036] (1) mixing the epoxy resin, the vegetable acid, the sulfur and the modified heat-conductive filler, then uniformly mixing the mixture by a ball mill, and obtaining a mixed material after degassing.

[0037] (2) hot-pressing the mixed material at 180°C for 2 hours to obtain the composite material.

[0038] Example 2

[0039] The embodiment discloses a composite material, which comprises the following components in parts by weight:

[0040] The epoxy resin is 10 parts, the vegetable acid is 10 parts, the sulfur is 2 parts, and the modified heat-conductive filler is 80 parts. The epoxy resin is bisphenol A type epoxy resin (Baliny Petrochemical, E44 type), the vegetable acid is oleic acid, and the heat-conductive filler is boron nitride. The method for modifying the heat-conductive filler is the same as that in Example 1.

[0041] The embodiment also discloses a preparation method of the composite material, which comprises the following steps:

[0042] (1) mixing the epoxy resin, the vegetable acid, the sulfur and the modified heat-conductive filler, then uniformly mixing the mixture by a ball mill, and obtaining a mixed material after degassing.

[0043] (2) hot-pressing the mixed material at 180°C for 6 hours to obtain the composite material.

[0044] Example 3

[0045] The difference between the composite material and Example 1 is that the composite material comprises the following components in parts by weight:

[0046] The epoxy resin is 10 parts, the vegetable acid is 10 parts, the sulfur is 2 parts, and the modified heat-conductive filler is 80 parts. The epoxy resin is bisphenol A type epoxy resin (Baliny Petrochemical, E44 type), the vegetable acid is ricinoleic acid, and the heat-conductive filler is diamond.

[0047] The modification method of the modified heat-conductive filler is different from that of Example 1 in that the terminal double-bond silane coupling agent is allyltrimethoxysilane.

[0048] Example 4

[0049] Different from Example 1 is that the composite material comprises the following components in parts by weight:

[0050] Epoxy resin 10 parts; vegetable acid 10 parts; sulfur 2 parts; modified heat-conductive filler 80 parts. Among them, the epoxy resin is bisphenol A type epoxy resin (Baliny Petrochemical, E44 type), the vegetable acid is tung oil acid, and the heat-conductive filler is aluminum oxide.

[0051] The modification method of the modified heat-conductive filler is different from that of Example 1 in that the terminal double-bond silane coupling agent is vinyltriethoxysilane.

[0052] Example 5

[0053] Different from Example 1 is that the composite material comprises the following components in parts by weight:

[0054] Epoxy resin 10 parts; vegetable acid 10 parts; sulfur 2 parts; modified heat-conductive filler 80 parts. Among them, the epoxy resin is bisphenol A type epoxy resin (Baliny Petrochemical, E44 type), the vegetable acid is tung oil acid, and the heat-conductive filler is aluminum oxide.

[0055] Example 6

[0056] Different from Example 1 is that the epoxy resin comprises bisphenol S type epoxy resin (Zhi Lun New Material Technology (Xi'an) Co., Ltd., ZLF-160H) and phenolic type epoxy resin (Hongchang Electronic Material Co., Ltd., GEBR558K75), and the weight ratio of the bisphenol S type epoxy resin and the phenolic type epoxy resin is 70:30.

[0057] Example 7

[0058] Different from Example 1 is that the epoxy resin comprises bisphenol S type epoxy resin (Zhi Lun New Material Technology (Xi'an) Co., Ltd., ZLF-160H) and phenolic type epoxy resin (Hongchang Electronic Material Co., Ltd., GEBR558K75), and the weight ratio of the bisphenol S type epoxy resin and the phenolic type epoxy resin is 90:10.

[0059] Comparative Example 1

[0060] Different from Example 1 is that no sulfur is added in the composite material.

[0061] Comparative Example 2

[0062] The difference from Example 1 is that in the modification method of the modified heat-conducting filler, equal mass of KH-560 is used instead of 3-methacryloxypropyltrimethoxysilane.

[0063] Comparative Example 3

[0064] The difference from Example 1 is that in the composite, equal mass of methyltetrahydrophthalic anhydride is used instead of undecylenic acid.

[0065] Comparative Example 4

[0066] The difference from Example 1 is that the composite comprises the following components by weight:

[0067] Epoxy resin 10 parts; vegetable oil acid 10 parts; sulfur 0.5 parts; modified heat-conducting filler 80 parts.

[0068] Comparative Example 5

[0069] The difference from Example 1 is that the composite comprises the following components by weight:

[0070] Epoxy resin 10 parts; vegetable oil acid 10 parts; sulfur 4 parts; modified heat-conducting filler 80 parts.

[0071] Comparative Example 6

[0072] The difference from Example 1 is that the composite comprises the following components by weight:

[0073] Epoxy resin 10 parts; vegetable oil acid 10 parts; sulfur 2 parts; modified heat-conducting filler 65 parts.

[0074] Comparative Example 7

[0075] The difference from Example 1 is that the composite comprises the following components by weight:

[0076] Epoxy resin 10 parts; vegetable oil acid 10 parts; sulfur 2 parts; modified heat-conducting filler 95 parts.

[0077] Comparative Example 8

[0078] The difference from Example 1 is that in the composite, equal mass of 1,3-propanedithiol is used instead of sulfur.

[0079] Performance detection

[0080] The composite materials prepared in the above examples and comparative examples are respectively subjected to the following performance detection.

[0081] 1. Tensile strength: tested according to GB / T 1040.1-2018 method.

[0082] 2. Thermal conductivity: tested according to ASTM D5470-17(2024) method.

[0083] 3. Voltage resistance test: the voltage resistance performance of the composite material is tested by Taiwan Chroma 19073.

[0084] 4. Recyclability: the sample is sheared and then hot-pressed again, and the temperature and time of the second hot-pressing are the same as before hot-pressing; the performance of the composite material after three recycling hot-pressing processes is tested.

[0085] The above test results are shown in Tables 1 and 2.

[0086] Table 1: Performance test results of samples

[0087]

[0088] Table 2: Performance test results of samples after three recycling

[0089]

[0090] According to Examples 1-5 in Table 1, under the same addition amount of modified thermal conductive filler, the mechanical properties of the composite material are not much different, and the difference in thermal conductivity is determined by the thermal conductivity of the powder itself. The composite material described in the application has excellent thermal conductivity and electrical insulation performance.

[0091] From the comparison of Example 1 and Comparative Example 1, it can be seen that Example 1 introduces sulfur into the polymer network, and the sulfur undergoes a reverse vulcanization ring-opening polymerization reaction with unsaturated olefins at high temperature. The polymer network has a dynamic disulfide bond, so it still has performance comparable to that of the material prepared for the first time after three recycling hot-pressing processes. However, no sulfur is added in Comparative Example 1, and no reverse vulcanization reaction occurs. Only unsaturated olefin polymerization and carboxylic acid-epoxy ring-opening reaction occur in the system at high temperature. The polymer network does not have a dynamic bond, and recycling and reprocessing are poor.

[0092] From the comparison of Example 1 and Comparative Example 2, it can be seen that Comparative Example 2 uses KH-560 modified thermal conductive powder. The thermal conductive powder and the polymer network are difficult to form effective chemical crosslinking during the curing process, resulting in poor thermal conductivity and a large loss in performance of the composite material after three recycling processes.

[0093] From the comparison of Example 1 and Comparative Example 3, it can be seen that Comparative Example 3 uses methyltetrahydrophthalic anhydride, which is a conventional curing agent in the epoxy resin field. Reverse vulcanization ring-opening polymerization occurs between sulfur and the thermal conductive powder, but only chain entanglement occurs in the epoxy resin network, so the overall performance is weak, and the performance decreases significantly after three recycling processes.

[0094] From the comparison of Example 1 and Comparative Examples 4-7, it can be seen that if the amount of sulfur or modified heat-conductive filler is too large or too small, the performance of the composite material will be affected to some extent. Therefore, only by controlling the amount of sulfur and modified heat-conductive filler within the range of the present application, can the composite material have excellent thermal conductivity, electrical insulation performance, thermal processing performance and recyclability.

[0095] From the comparison of Example 1 and Comparative Example 8, it can be seen that in Example 1, sulfur is introduced into the polymer network, and the sulfur undergoes a reverse vulcanization ring-opening polymerization reaction with unsaturated olefins at high temperature, and the polymer network has dynamic disulfide bonds, so that after three times of hot-pressing recycling, the material still has performance comparable to that of the material prepared for the first time. However, in Comparative Example 8, 1,3-propanedithiol is used instead of sulfur, and no reverse vulcanization reaction occurs, and only unsaturated olefin polymerization and carboxylic acid-epoxy ring-opening reactions occur in the system at high temperature, and the polymer network does not have dynamic bonds, resulting in poor recycling and reprocessing.

[0096] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and do not limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A composite material, characterized in that The composition comprises the following components in parts by weight: 10-50 parts of epoxy resin; 10-20 parts of vegetable oleic acid; 1-3 parts of sulfur; 70-90 parts of modified thermally conductive filler; the modified thermally conductive filler is obtained by modifying the thermally conductive filler with a terminal double-bond silane coupling agent; The plant oleic acid includes at least one of eleostearic acid, linolenic acid, linoleic acid, soybean oleic acid, oleic acid, ricinoleic acid, and undecylenic acid.

2. The composite material according to claim 1, wherein The D50 particle size of the thermal conductive filler is 30-120 μm.

3. The composite material according to claim 1, wherein The modification method of the modified thermal conductive filler is as follows: the dried thermal conductive filler is stirred and modified in an ethanol solution containing a terminal double-bond silane coupling agent, and then dried.

4. The composite material according to claim 3, wherein The mass of the double-bond-terminated silane coupling agent is 1-2% of the mass of the thermal conductive filler.

5. The composite material according to claim 1, wherein The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, novolac epoxy resin, and alicyclic epoxy resin.

6. The composite material according to claim 5, wherein The epoxy resin includes bisphenol S epoxy resin and novolac epoxy resin, and the weight ratio of the bisphenol S epoxy resin to the novolac epoxy resin is (70-90): (10-30).

7. The composite material according to claim 1, wherein The thermally conductive filler includes at least one of boron nitride, aluminum nitride, aluminum oxide, diamond, and aluminum hydroxide.

8. The composite material according to claim 1, wherein The double-bond-terminated silane coupling agent includes at least one of 3-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, and vinyltriethoxysilane.

9. A method for preparing the composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The epoxy resin, vegetable oil acid, sulfur and modified thermal conductive filler are uniformly mixed to obtain a mixture; and the mixture is then hot-pressed to obtain a composite material.

10. Use of the composite material according to any one of claims 1 to 8 in green electronic packaging materials, electrical insulation coatings, and sustainable composite materials.

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