Preparation method of an epoxy resin-filled melamine carbide foam / molybdenum disulfide electronic component packaging material

Abstract

The present invention discloses a preparation method of an epoxy resin-filled carbonized melamine foam / molybdenum disulfide electronic component packaging material, belonging to the field of new material technology. The epoxy resin-filled carbonized melamine foam / molybdenum disulfide material in the present invention contains 95 wt% of epoxy resin and 5 wt% of carbonized melamine foam / molybdenum disulfide wave-absorbing agent; the preparation method of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent includes the following steps: carbonizing melamine foam to obtain carbonized melamine foam, and then mixing it with a molybdenum source and sulfur source precursor solution, reacting to obtain the carbonized melamine foam / molybdenum disulfide wave-absorbing agent. In the carbonized melamine foam / molybdenum disulfide, the carbonized melamine foam with a three-dimensional network structure provides an ideal path for phonon and electron transmission. 1T / 2H-molybdenum disulfide grows in-situ on the surface of the carbonized melamine foam, resulting in a reduction in the direct reflection of electromagnetic waves and effectively improving the poor impedance.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and particularly to a method for preparing an electronic component packaging material of epoxy resin filled with carbonized melamine foam / molybdenum disulfide. Background Art

[0002] Packaging materials play a crucial role in ensuring the long-term stable operation of electronic devices. With the advent of the 5G era, electronic components are gradually developing towards miniaturization and precision, resulting in a significant reduction in the heat dissipation space of these electronic components. In addition, the proliferation of useless electromagnetic waves also has an irreversible impact on precision electronic devices. To solve these problems, there is an urgent need to design multifunctional packaging materials with excellent thermal conductivity and electromagnetic protection capabilities.

[0003] Ceramic materials such as aluminum nitride and alumina are usually used to construct a thermal conduction network to improve the thermal conductivity of the packaging polymer matrix. A large number of research has been carried out on improvement schemes in directions such as changing the particle size, orientation, and interfacial interaction of these materials. However, when constructing a thermal conduction network, a relatively large filler filling amount is usually required, which conflicts with the lightweight requirements of highly integrated electronic devices. Moreover, the electromagnetic protection ability of electronic components using these ceramic materials is poor. Therefore, it is of great significance to design and develop packaging composite materials with low filling, high thermal conductivity, and electromagnetic protection performance.

[0004] Epoxy resin has attracted much attention in the field of electronic packaging due to its excellent corrosion resistance, high mechanical properties, and low electrical conductivity. However, with the continuous miniaturization of high-power devices, how to improve the limited thermal conductivity of epoxy resin has become a major challenge. In addition, the wave-transmitting characteristics of epoxy resin are not conducive to protecting precision electronic devices from harmful electromagnetic wave interference.

[0005] Carbon nanomaterials have attracted much attention because of their low density and excellent physical and chemical properties, which can enhance the thermal conductivity and electromagnetic interference resistance of the epoxy resin matrix at the same time. However, when constructing a thermal conduction and conduction network, an excessive filling amount is still an inevitable problem for these one-dimensional and two-dimensional carbon nanomaterials. Moreover, the excessive electrical conductivity will also limit their application in some insulating devices. Therefore, how to select materials and structure construction to achieve lightweight, good thermal conductivity, and electromagnetic protection performance is the current problem and challenge. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method of an epoxy resin-filled melamine carbide foam / molybdenum disulfide electronic component packaging material. In the present invention, a melamine carbide foam / molybdenum disulfide wave absorber is filled in an epoxy resin matrix by a vacuum impregnation method. In the melamine carbide foam / molybdenum disulfide, the melamine carbide foam with a three-dimensional network structure provides an ideal path for phonon and electron transmission. 1T / 2H-molybdenum disulfide grows in-situ on the surface of the melamine carbide foam, resulting in a reduction in direct reflection of electromagnetic waves and effectively improving the poor impedance.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention: Provide an epoxy resin-filled melamine carbide foam / molybdenum disulfide material, which contains 95 wt% of epoxy resin and 5 wt% of melamine carbide foam / molybdenum disulfide wave absorber;

[0009] The preparation method of the melamine carbide foam / molybdenum disulfide wave absorber includes the following steps: carbonize the melamine foam to obtain melamine carbide foam, and then mix it with a molybdenum source sulfur source precursor solution and react to obtain the melamine carbide foam / molybdenum disulfide wave absorber.

[0010] Preferably, the carbonization treatment is to heat to 800 °C at a rate of 5 °C / min under a protective atmosphere and hold for 2 h.

[0011] Preferably, in the molybdenum source sulfur source precursor solution, the molybdenum source is sodium molybdate and the sulfur source is L-cysteine.

[0012] More preferably, the mass ratio of the sulfur source to the molybdenum source in the molybdenum source sulfur source precursor solution > 1.1, and the concentration of the sulfur source in the molybdenum source sulfur source precursor solution is 2.1 - 4.3 mg / mL.

[0013] Preferably, the temperature of the reaction is 180 °C and the time is 24 h.

[0014] Under the reaction conditions of the present invention, a layer of molybdenum disulfide can grow on the surface of the melamine carbide foam.

[0015] During the reaction process, excessive L-cysteine will adsorb on the surface of the initial molybdenum disulfide crystal, resulting in incomplete sulfidation of molybdenum disulfide, leading to the residual lattice oxygen and the formation of sulfur vacancies in its structure, thereby causing lattice distortion and inducing the formation of the 1T phase, obtaining 1T / 2H-phase molybdenum disulfide. The requirements for the addition amounts of the sulfur source and the molybdenum source are strict during this reaction process. If the ratio of the two is less than 1.1, it is impossible to form 1T / 2H-phase molybdenum disulfide well.

[0016] The second technical solution of the present invention: provide a preparation method of the above-mentioned epoxy resin-filled melamine carbide foam / molybdenum disulfide material, comprising the following steps:

[0017] Fill the epoxy resin into the melamine carbide foam / molybdenum disulfide absorbent by vacuum impregnation to obtain the epoxy resin-filled melamine carbide foam / molybdenum disulfide material.

[0018] Preferably, the temperature of the vacuum impregnation is 120 °C, the pressure is 1 Pa, and the time is 6 h.

[0019] The third technical solution of the present invention: provide an application of the above-mentioned epoxy resin-filled melamine carbide foam / molybdenum disulfide material in the field of electronic component packaging materials.

[0020] The technical principle of the present invention is as follows:

[0021] The three-dimensional structure of melamine carbide foam can enable the establishment of high thermal conductivity and conductive networks under extremely low filling amounts. Different from the anisotropic distribution of other one-dimensional and two-dimensional carbon materials filled in epoxy resin, the three-dimensional interconnected carbon skeleton provides an ideal isotropic pathway for heat and electron transport. Therefore, this three-dimensional carbon structure with low density, uniform size, and directionality shows great potential in the application of the thermal conductivity of low-loading epoxy resin-based composites. However, for electromagnetic wave absorption, due to the high conductivity of melamine carbide foam resulting in poor impedance, a single carbon skeleton is prone to directly reflect electromagnetic waves. Therefore, improving the impedance of the composite material by introducing molybdenum disulfide with a low dielectric constant is the key to reducing the direct reflection of electromagnetic waves and enhancing the electromagnetic wave absorption ability of the composite material.

[0022] Molybdenum disulfide has a large surface area, adjustable structure, and excellent electrical properties, and usually exhibits a stable trigonal prism 2H phase. However, this structure shows semiconductor characteristics, narrow interlayer spacing, insufficient active sites, and basal plane inertness, resulting in limited dielectric loss of electromagnetic waves. Therefore, while improving the impedance matching of carbon materials, it is also crucial to consider the electromagnetic wave absorption ability of molybdenum disulfide itself. On this basis, through defect engineering, preferential exposure of active planes, and phase engineering, the inherent structure and properties of 2H-molybdenum disulfide have been improved. In particular, phase engineering shows that through the control of the preparation method, the 2H phase can undergo lattice distortion and transform into a metastable octahedral 1T phase. Compared with 2H-molybdenum disulfide, metallic 1T-molybdenum disulfide has more basal plane / edge active sites, resulting in a greatly enhanced dielectric loss ability of molybdenum disulfide. Therefore, by using 1T / 2H-molybdenum disulfide to modify the three-dimensional carbon skeleton and vacuum impregnating the epoxy resin in the composite material, a dual-functional electronic component packaging material with excellent thermal conductivity and electromagnetic wave absorption properties can be obtained.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] In the present invention, the carbonized melamine foam / molybdenum disulfide wave-absorbing agent is filled in the epoxy resin matrix by a vacuum impregnation method. Among them, the epoxy resin serves as the matrix, providing mechanical properties, moisture resistance and corrosion resistance for the encapsulation material. In the carbonized melamine foam / molybdenum disulfide, the carbonized melamine foam with a three-dimensional network structure provides an ideal path for phonon and electron transmission, ensuring that the composite material still has effective heat conduction and conduction paths at a relatively low filling amount. 1T / 2H-molybdenum disulfide grows in-situ on the surface of the carbonized melamine foam, resulting in a reduction in direct reflection of electromagnetic waves and effectively improving the poor impedance. In addition, a large number of lattice oxygen, sulfur vacancies and 1T phases in 1T / 2H-molybdenum disulfide lead to an enhancement of dipole polarization and conduction loss capabilities, further improving the dielectric loss ability of the composite material.

[0025] The combination of the two materials in the present invention generates more interfaces, enhancing the interfacial polarization ability. At the same time, a large amount of scattering of electromagnetic waves at the interfaces increases the loss paths, causing more dissipation of electromagnetic waves. Therefore, after only 5% of the carbonized melamine foam / molybdenum disulfide is filled, the epoxy resin encapsulation material realizes the synchronous enhancement of heat conduction and electromagnetic wave absorption performance, and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 Macrophotograph of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent prepared in Example 1.

[0028] Figure 2 Scanning electron microscope image of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent prepared in Example 1.

[0029] Figure 3 Transmission electron microscope image of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent prepared in Example 1.

[0030] Figure 4 High-resolution transmission electron microscope image of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent prepared in Example 1.

[0031] Figure 5 Scanning electron microscope image of the carbonized melamine foam / molybdenum disulfide wave-absorbing agent prepared in Example 2.

[0032] Figure 6Scanning electron micrograph of the melamine carbide foam / molybdenum disulfide absorbent prepared in Example 3. Detailed Description of the Invention

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing particular embodiments and are not intended to limit the present invention.

[0034] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention.

[0036] Regarding the terms "comprising", "including", "having", "containing", etc. used in the present invention, they are all open-ended terms, meaning including but not limited to.

[0037] Unless otherwise specified, "room temperature" in the present invention is calculated as 20 - 30 °C.

[0038] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0039] Example 1

[0040] Preparation of epoxy resin filled melamine carbide foam / molybdenum disulfide material:

[0041] 1) Preparation of melamine carbide foam / molybdenum disulfide absorbent

[0042] a) Wash the melamine foam in an ethanol / deionized water solution with a mass fraction of 1:1 for 16 h; dry the washed melamine foam in a forced-air drying oven at 70 °C for 24 h; then transfer the dried melamine foam to a tubular furnace, heat it to 800 °C at a rate of 5 °C / min under an argon atmosphere, hold for 2 hours and then cool to room temperature to obtain the melamine carbide foam.

[0043] b) Immerse 0.1 g of carbonized melamine foam into 70 mL of deionized aqueous solution containing 0.1 g of sodium molybdate and 0.15 g of L-cysteine for 12 h, then transfer it to a 100 mL hydrothermal reactor and react at 180 °C for 24 h. Take it out, soak and wash the generated carbonized melamine foam / molybdenum disulfide composite material with ethanol and deionized water three times, 12 h each time, and then remove the residual deionized water by freeze-drying to obtain the carbonized melamine foam / molybdenum disulfide absorbent.

[0044] 2) Prepare epoxy resin filled carbonized melamine foam / molybdenum disulfide material

[0045] Place the carbonized melamine foam / molybdenum disulfide absorbent with a mass ratio of 1:19 and bisphenol A epoxy resin (purchased from Changshu Jiafa Chemical Co., Ltd., JY257) premixed with a curing agent in a mold, transfer it to a vacuum drying oven, and mold it at 120 °C and 1 Pa for 6 h to obtain the epoxy resin filled carbonized melamine foam / molybdenum disulfide material.

[0046] Use an Agilent N5244A vector network analyzer to measure the electromagnetic parameters of the epoxy resin filled carbonized melamine foam / molybdenum disulfide material in Example 1. The minimum reflection loss value of the product appears at 3.9 mm, which is -64.8 dB, and the effective absorption bandwidth is 5.44 GHz. The maximum effective absorption bandwidth of this material is 8.48 GHz at 3.3 mm, which can cover the entire X and Ku bands. The thermal conductivity of the product is measured by the transient hot wire method to be 0.41 W / m·K.

[0047] Figure 1 Macroscopic photograph of the carbonized melamine foam / molybdenum disulfide absorbent prepared for Example 1. From Figure 1 it can be seen that the fabricated composite material can be placed independently on the flower due to its light weight and low density.

[0048] Figure 2 Scanning electron microscope image of the carbonized melamine foam / molybdenum disulfide absorbent prepared for Example 1. From Figure 2 it can be seen that molybdenum disulfide grows uniformly on the surface of the carbonized melamine foam.

[0049] Figure 3 Transmission electron microscope image of the carbonized melamine foam / molybdenum disulfide absorbent prepared for Example 1. From Figure 3 it is observed that the interlayer spacing of molybdenum disulfide is 0.9 nm.

[0050] Figure 4 High-resolution transmission electron microscope image of the carbonized melamine foam / molybdenum disulfide absorbent prepared for Example 1. From Figure 4It can be observed that there is a coexisting distribution of the 1T / 2H phase in molybdenum disulfide.

[0051] Example 2

[0052] The difference from Example 1 is only that step 1) b) is modified to:

[0053] Immerse 0.1 g of carbonized melamine foam in 70 mL of deionized aqueous solution containing 0.15 g of sodium molybdate and 0.225 g of L-cysteine for 12 h, then transfer it to a 100 mL hydrothermal reaction kettle and react at a temperature of 180 °C for 24 h. Take it out, soak and wash the generated carbonized melamine foam / molybdenum disulfide composite material with ethanol and deionized water 3 times, 12 h each time, and then remove the residual deionized water by freeze-drying to obtain a carbonized melamine foam / molybdenum disulfide absorbent.

[0054] The electromagnetic parameters of the epoxy resin-filled carbonized melamine foam / molybdenum disulfide material in Example 2 were measured using an Agilent N5244A vector network analyzer. The minimum reflection loss value of the product appears at 3.5 mm, which is -30.7 dB, and the effective absorption bandwidth is 6.32 GHz. The thermal conductivity of the product was measured by the transient hot wire method to be 0.39 W / m·K.

[0055] Figure 5 SEM image of the carbonized melamine foam / molybdenum disulfide absorbent prepared for Example 2. From Figure 5 It can be seen that compared with Example 1, the growth content of molybdenum disulfide in this example increases.

[0056] Example 3

[0057] The difference from Example 1 is only that step 1) b) is modified to:

[0058] Immerse 0.1 g of carbonized melamine foam in 70 mL of deionized aqueous solution containing 0.2 g of sodium molybdate and 0.3 g of L-cysteine for 12 h, then transfer it to a 100 mL hydrothermal reaction kettle and react at a temperature of 180 °C for 24 h. Take it out, soak and wash the generated carbonized melamine foam / molybdenum disulfide composite material with ethanol and deionized water 3 times, 12 h each time, and then remove the residual deionized water by freeze-drying to obtain a carbonized melamine foam / molybdenum disulfide absorbent.

[0059] The electromagnetic parameters of the epoxy resin-filled melamine cyanurate foam / molybdenum disulfide material of Example 2 were measured using an Agilent N5244A vector network analyzer, and the minimum reflection loss value of the product was found to be -8.0 dB at 3.5 mm. The thermal conductivity of the product was measured by the transient hot wire method to be 0.35 W / m·K.

[0060] Figure 6 It is the scanning electron microscope image of the melamine cyanurate foam / molybdenum disulfide absorbent prepared in Example 3. From Figure 6 it can be seen that, compared with Example 2, the growth content of molybdenum disulfide in this example is further increased.

[0061] Comparative Example 1

[0062] The difference from Example 1 is only that the epoxy resin mixed with the curing agent is directly placed in a mold, transferred to a vacuum drying oven, and molded at 120 °C and 1 Pa for 6 h to obtain an epoxy resin sample.

[0063] It was measured that the thermal conductivity of the epoxy resin sample was 0.17 W / m·K, and the minimum reflection loss value was -1.6 dB.

[0064] Comparative Example 2

[0065] The difference from Example 1 is only that the melamine cyanurate foam / molybdenum disulfide absorbent in step 2) is replaced with an equal mass of the melamine cyanurate foam in a) of step 1) to obtain an epoxy resin-filled melamine cyanurate foam material.

[0066] It was measured that the thermal conductivity of the epoxy resin-filled melamine cyanurate foam material was 0.47 W / m·K, the minimum reflection loss value appeared at 2.3 mm and was -13.3 dB, and the effective absorption bandwidth was 4.77 GHz.

[0067] Comparative Example 3

[0068] The difference from Example 1 is only that the mass of L-cysteine in b) of step 1) is adjusted to 0.1 g.

[0069] It was measured that the thermal conductivity of the epoxy resin-filled melamine cyanurate foam / 2H-molybdenum disulfide material was 0.43 W / m·K, the minimum reflection loss value appeared at 3.1 mm and was -29.8 dB, and the effective absorption bandwidth was 5.18 GHz.

[0070] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An epoxy resin-filled melamine carbide foam / molybdenum disulfide material, characterized in that, The material contains 95 wt% of epoxy resin and 5 wt% of carbonized melamine foam / molybdenum disulfide microwave absorber; The preparation method of the carbonized melamine foam / molybdenum disulfide microwave absorber includes the following steps: carbonize the melamine foam to obtain carbonized melamine foam, and then mix it with a molybdenum source sulfur source precursor solution, and react to obtain the carbonized melamine foam / molybdenum disulfide microwave absorber; In the molybdenum source sulfur source precursor solution, the molybdenum source is sodium molybdate and the sulfur source is L-cysteine; In the molybdenum source sulfur source precursor solution, the mass ratio of the sulfur source to the molybdenum source > 1.1, and the concentration of the sulfur source in the molybdenum source sulfur source precursor solution is 2.1 - 4.3 mg / mL.

2. The epoxy resin-filled melamine carbide foam / molybdenum disulfide material according to claim 1, wherein, The carbonization treatment is to heat to 800 °C at a rate of 5 °C / min under a protective atmosphere and hold for 2 h.

3. The epoxy resin-filled melamine carbide foam / molybdenum disulfide material according to claim 1, wherein The temperature of the reaction is 180 °C and the time is 24 h.

4. A method for preparing the epoxy resin-filled melamine carbide foam / molybdenum disulfide material according to any one of claims 1 to 3, characterized in that, Including the following steps: Fill the epoxy resin into the carbonized melamine foam / molybdenum disulfide microwave absorber by vacuum impregnation to obtain the epoxy resin-filled carbonized melamine foam / molybdenum disulfide material.

5. The preparation method according to claim 4, characterized in that, The temperature of the vacuum impregnation is 120 °C, the pressure is 1 Pa, and the time is 6 h.

6. Use of the epoxy resin-filled carbonized melamine foam / molybdenum disulfide material according to any one of claims 1 - 3 in the field of electronic component packaging materials.

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