All-organic epoxy resin composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of functional composite materials, and particularly relates to an all-organic epoxy resin composite material as well as a preparation method and application thereof. The method comprises the following steps: S1, heating, melting and blending epoxy resin and phenolic hydroxyl polyphenyl ether to obtain a composite system; s2, adding a curing agent and a catalyst into the composite system, heating, stirring, reacting, vacuumizing, defoaming, casting the obtained mixed solution into a mold, curing, cooling and demolding to obtain the all-organic epoxy resin composite material. The heat conductivity coefficient of the obtained composite material is improved by 44.2% compared with that of pure epoxy resin, and the thermal expansion coefficient is reduced by 32.8%. The method is mild in condition, short in technological process, low in energy consumption and suitable for large-scale production, an innovative thought and an effective strategy are provided for development of a high-performance all-organic electronic packaging material, and silicon-free and ceramic-free all-organic upgrading of the packaging field is expected to be promoted.

Description

Technical Field

[0001] This invention belongs to the field of functional composite materials technology, and particularly relates to an all-organic epoxy resin composite material, its preparation method and application. Background Technology

[0002] Electronic packaging materials are an indispensable component of integrated circuits and power devices, undertaking important functions such as sealing and bonding, support and protection, thermal conductivity, and insulation. Based on substrate type, existing packaging systems mainly include metal-based packaging materials, ceramic-based packaging materials, and polymer-based packaging materials. Among these, polymer-based packaging materials have become the fastest-growing and most widely used electronic packaging materials due to their lightweight, low cost, ease of processing, low moisture absorption, and excellent insulation properties.

[0003] Among polymer encapsulation materials, epoxy resin is widely used in electronic packaging and high-performance fiber composite materials due to its advantages such as high bonding strength, low curing shrinkage, good chemical corrosion resistance, high heat resistance, wide availability of raw materials and low price. It is currently the most technologically mature resin material with the highest market share, and it has almost "defined" the current industry standard for molding compounds.

[0004] However, epoxy resins have a low intrinsic thermal conductivity and a high coefficient of thermal expansion. With the advancement of 5G / 6G communication technologies, electronic components are developing towards higher frequencies, higher power, and higher integration. Traditional epoxy encapsulation materials face the dual challenges of "heat dissipation bottleneck" and "thermal mismatch," making it increasingly difficult to meet the encapsulation requirements of advanced electronic devices.

[0005] To overcome this limitation, the common industrial strategy is to add a high proportion of inorganic fillers (such as SiO2, AlN, Al2O3, BN, Si3N4, etc.) to epoxy resin. For example, Chinese patent CN202511027234.X improves the heat resistance, glass transition temperature, and reduces the coefficient of thermal expansion of the material by adding high amounts of silica, lamellar aluminum nitride, and lamellar alumina. However, high filling of inorganic powders often leads to increased system viscosity, making it difficult to fill micro-gaps, and the weak interfacial bonding between inorganic powders and resin can easily cause increased brittleness and decreased reliability. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an all-organic epoxy resin composite material, its preparation method, and its application, which improves the thermal conductivity of the epoxy resin composite material while reducing its thermal expansion properties.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing an all-organic epoxy resin composite material, the method comprising: S1, heating and melting epoxy resin and phenolic hydroxyl polyphenylene ether to obtain a composite system; S2, adding a curing agent and a catalyst to the composite system, heating and stirring to react, and then degassing under vacuum, casting the resulting mixture into a mold, curing, cooling and demolding to obtain the all-organic epoxy resin composite material.

[0008] Furthermore, a nano-aramid fiber dispersion is also added to the composite system; S1 specifically includes: S11, heating and melting epoxy resin and phenolic hydroxyl polyphenylene ether to obtain a polyphenylene ether / epoxy resin blend solution; S12, adding nano-aramid fibers to acetone and strongly ultrasonically dispersing them to obtain a nano-aramid fiber dispersion; S13, adding the nano-aramid fiber dispersion dropwise to the polyphenylene ether / epoxy resin blend solution, magnetically stirring at room temperature, and then evaporating the acetone to obtain the composite system.

[0009] Furthermore, the curing agent is at least one of methyltetrahydrophthalic anhydride (MTHPA), methylhexahydrophthalic anhydride (MHHPA), and methylnadic anhydride (MNA); the amount of the curing agent is 60-85 wt% of the epoxy resin; and the catalyst is 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), with an amount of 0.5-3 wt% of the epoxy resin.

[0010] Furthermore, the amount of phenolic hydroxyl polyphenylene ether used is 5 to 30 wt% of epoxy resin; the amount of nano-aramid fiber used is 0.1 to 0.4 wt% of epoxy resin.

[0011] Furthermore, S11 specifically includes: stirring at 200–800 r / min at 80–120 °C for 4–8 h. Preferably, the heating temperature is 90–100 °C, the stirring speed is 400–500 r / min, and the reaction time is 5–6 h. The strong ultrasonic dispersion time in S12 is 1–2 h.

[0012] Furthermore, S13 specifically includes: magnetic stirring at room temperature for 1–4 hours; and evaporation of acetone by drying at 40–60 °C for 4–12 hours. Preferably, the magnetic stirring at room temperature is 1–2 hours, and the drying time for evaporating acetone is 6–8 hours.

[0013] Further, S2 specifically includes: after adding the curing agent and catalyst, reacting with magnetic stirring at 60–90 °C for 10–30 min. Preferably, the heating temperature is 70–80 °C, and the magnetic stirring is performed for 10–15 min. As a preferred embodiment, degassing is performed at -0.085–0.095 MPa and 70–80 °C for 10–20 min.

[0014] Furthermore, S2 also includes: cleaning the mold with anhydrous ethanol, sealing the small holes on the mold with vacuum grease after drying, then spraying a release agent and drying at 80 ℃ for 20-30 min; transferring the mixture into the mold, and after curing and cooling, demolding to obtain the all-organic epoxy resin composite material.

[0015] The present invention also provides an all-organic epoxy resin composite material prepared by the above-mentioned method for preparing all-organic epoxy resin composite material.

[0016] This invention also provides an application of the above-mentioned all-organic epoxy resin composite material in the field of electronic packaging materials.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Using epoxy resin as raw material, a low-loss polyphenylene ether / epoxy resin blend solution was prepared by melt blending with phenolic hydroxyl polyphenylene ether resin; and using polyphenylene ether / epoxy resin as matrix, it was combined with nano-aramid fibers prepared by chemical pyrolysis to prepare a fully organic epoxy resin composite material of nano-aramid fibers / polyphenylene ether / epoxy resin with low thermal expansion and high thermal conductivity.

[0018] (2) Compared with the traditional approach of reducing the coefficient of thermal expansion by "high content of inorganic filler", the present invention can effectively reduce the coefficient of thermal expansion of composite material by introducing only a small amount of low thermal expansion nano-aramid fiber, and effectively improve the performance sacrifice problem of "high filler-high brittleness", while taking into account both dimensional stability and mechanical toughness.

[0019] (3) The preparation method provided by the present invention has mild reaction conditions, low production cost and environmental protection. The all-organic composite material obtained also has good heat resistance and mechanical strength, and has great application potential in the field of electronic packaging materials. Attached Figure Description

[0020] Figure 1 SEM images of cross sections of nano-aramid fibers and nano-aramid fiber / polyphenylene ether / epoxy resin composite materials provided in embodiments of the present invention; Figure 2 A graph showing the average coefficient of thermal expansion of the nano-aramid fiber / polyphenylene ether / epoxy resin composite material provided in the embodiments of the present invention; Figure 3 The graph shows the thermal conductivity values ​​of the nano-aramid fiber / polyphenylene ether / epoxy resin composite material provided in the embodiments of the present invention. Detailed Implementation

[0021] This invention provides an all-organic epoxy resin composite material, its preparation method, and its application. The preparation method of the all-organic epoxy resin composite material includes: S1, heating and melting epoxy resin and phenolic hydroxyl polyphenylene ether to obtain a composite system; S2, adding a curing agent and a catalyst to the composite system, heating and stirring to react, and then degassing under vacuum. The resulting mixture is then cast into a mold, cured, cooled, and demolded to obtain the all-organic epoxy resin composite material.

[0022] Preferably, the composite system also incorporates a nano-aramid fiber dispersion, with the following technical route: using epoxy resin as the matrix, phenolic hydroxyl polyphenylene ether is introduced for melt blending modification to obtain a polyphenylene ether / epoxy blend system with high toughness and good heat resistance; aramid fibers are exfoliated into nano-aramid fibers using a controlled chemical pyrolysis process and uniformly dispersed in the polyphenylene ether / epoxy matrix; after vacuum degassing and curing, a fully organic epoxy resin composite material is obtained, specifically a nano-aramid fiber / polyphenylene ether / epoxy resin fully organic composite material. In this invention, the presence of weakly polar polyphenylene ether weakens the polarity of the epoxy resin crosslinking network, and the low thermal expansion nano-aramid fibers have strong interaction forces with the resin matrix, which can restrict their molecular chain movement and inhibit their thermal expansion. Furthermore, the one-dimensional rod-like structure of the nano-aramid fibers can overlap in the matrix to form thermally conductive pathways, constructing efficient phonon transport channels and endowing the material with excellent thermal conductivity. The thermal conductivity of the resulting composite material is increased by 44.2% compared to pure epoxy resin, while the coefficient of thermal expansion is reduced by 32.8%. The present invention features mild conditions, a short process flow, and low energy consumption, making it suitable for large-scale production. It provides innovative ideas and effective strategies for the development of high-performance all-organic electronic packaging materials, and is expected to drive the packaging field towards an all-organic upgrade that is "silicon-free and ceramic-free".

[0023] The present invention will now be described in detail with reference to specific embodiments. The embodiments given in this section are merely illustrative and should not be construed as limiting the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0025] In some embodiments of the present invention, the selected aramid fiber is a commercially available micron-sized para-aramid fiber, which has the characteristics of high strength, high modulus, high heat resistance, insulation, and low thermal expansion. It can be chemically pyrolyzed into nano-aramid fibers (ANFs). The resulting nano-aramid fibers not only retain many advantages of aramid fibers but also possess the high surface activity of nanomaterials, enabling them to generate strong interaction forces with the polymer matrix, restricting the movement of polymer molecular chains and suppressing their thermal expansion effect. Therefore, the present invention uses them as fillers in composites with polyphenylene ether / epoxy blends to reduce the coefficient of thermal expansion of the blend resin.

[0026] The epoxy resin used in this embodiment of the invention is preferably a bisphenol A type epoxy resin, and more specifically, the selected bisphenol A type epoxy resin is E51. The phenolic hydroxyl polyphenylene ether resin selected in this embodiment of the invention is SA90. SA90 is a low molecular weight polyphenylene ether resin with good compatibility with epoxy resin, exhibiting extremely low dielectric loss. It can weaken the polarity of the epoxy resin molecular chain, thereby reducing its dielectric loss. Furthermore, its molecular chain has flexibility, which is beneficial for improving the mechanical properties of the epoxy resin. The curing agent used in this embodiment of the invention is at least one of methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride, and the catalyst used is 2,4,6-tris(dimethylaminomethyl)phenol.

[0027] Preferably, the method for preparing nano-aramid fibers using chemical pyrolysis in this embodiment of the invention includes: taking an appropriate amount of para-aramid fibers and ultrasonically dispersing them in acetone, soaking them for one day to remove impurities, and drying them for later use; sequentially adding 1 g of dried para-aramid fibers, 1 g of KOH, and 500 mL of DMSO to a 1000 mL beaker, turning on magnetic stirring, setting the speed to 600 r / min, and magnetically stirring at room temperature for 3 days to obtain a bright red solution, namely, nano-aramid fiber / DMSO dispersion; adding an equal volume of deionized water to the nano-aramid fiber / DMSO dispersion, adjusting the stirring speed to 1000 r / min, and rapidly stirring to precipitate the nano-aramid fibers, then filtering under reduced pressure to obtain semi-dry nano-aramid fibers; then dispersing the nano-aramid fibers obtained in the previous step in 200 mL of acetone, filtering under reduced pressure and repeatedly washing to remove impurities and solvents, and collecting the nano-aramid fibers after vacuum drying at room temperature for later use.

[0028] Example 1 Add 60 g of epoxy resin to a reaction flask and preheat it to 80 °C until it reaches a fluid state. Increase the temperature to 100 °C and add 6 g of phenolic hydroxyl polyphenylene ether (PPE). Turn on the magnetic stirrer at 400–500 r / min and maintain the temperature for 5–6 h until the PPE is completely melted and the system is homogeneous and transparent. Cool to 80 °C, add 51 g of curing agent MHHPA and 0.6 g of catalyst DMP-30, and maintain the stirring speed at 400–500 r / min for 15 min. Then, place the mixture in an 80 °C vacuum drying oven and degas at -0.085–-0.095 MPa for 10–15 min. Pour the mixture into a stainless steel mold preheated to 80 °C, pre-cur at 80 °C for 1 h, then increase the temperature to 140 °C for 6 h. Allow it to cool naturally to room temperature and demold to obtain fully cured PPE / epoxy resin, denoted as S1.

[0029] Example 2 5 g of phenolic hydroxyl polyphenylene ether and 50 g of epoxy resin were added to a reaction flask. The reaction flask was placed on a magnetic stirrer at 100 ℃ and the speed was set to 400-500 r / min. The mixture was stirred at a constant speed for 5-6 h until the polyphenylene ether was completely melted, resulting in a polyphenylene ether / epoxy resin blend. 0.05 g of nano-aramid fiber was weighed and added to 10 mL of acetone. The mixture was then strongly ultrasonically dispersed for 1 h to obtain a nano-aramid fiber dispersion. The nano-aramid fiber dispersion was added dropwise to the polyphenylene ether / epoxy resin blend and mixed magnetically at room temperature for 1 h. The reaction flask was then placed in a 60 ℃ forced-air drying oven and kept at this temperature for 8 h to remove all acetone. Subsequently, the reaction flask was placed on an 80 °C magnetic stirrer, and 42.5 g MHHPA and 0.5 g DMP-30 were added. The stirring speed was maintained at 400–500 r / min for 15 min. Then, the mixture was placed in an 80 °C vacuum drying oven and degassed at -0.085–-0.095 MPa for 10–15 min. The mixture was poured into a mold and cured according to the program of “80 °C / 1 h + 140 °C / 6 h”. After cooling to room temperature, the mixture was demolded to obtain the all-organic epoxy resin composite material of the present invention, specifically a fully cured nano-aramid fiber / polyphenylene ether / epoxy resin composite material, denoted as S2.

[0030] Example 3 The difference between Example 3 and Example 2 is that the amount of nano-aramid fiber added is 0.1 g, while the rest of the steps are the same as in Example 2, and the resulting product is denoted as S3.

[0031] Example 4 The difference between Example 4 and Example 2 is that the amount of nano-aramid fiber added is 0.2 g, while the rest of the steps are the same as in Example 2, and the resulting product is denoted as S4.

[0032] Example 5 6 g of phenolic hydroxyl polyphenylene ether and 60 g of epoxy resin were added to a reaction flask. The flask was placed on a magnetic stirrer at 100 °C and the speed was set to 400–500 r / min. The mixture was stirred at a constant speed for 5–6 h until the polyphenylene ether was completely melted, resulting in a polyphenylene ether / epoxy resin blend. 0.24 g of nano-aramid fibers were added to 10 mL of acetone and strongly ultrasonically dispersed for 1 h to obtain a nano-aramid fiber dispersion. The nano-aramid fiber dispersion was added dropwise to the polyphenylene ether / epoxy resin blend and mixed magnetically at room temperature for 1 h. The reaction flask was then placed in a 60 °C forced-air drying oven and kept at this temperature for 8 h to evaporate the acetone. Subsequently, the reaction flask was placed on an 80 ℃ magnetic stirrer, and 36.0 g of MNA and 0.6 g of DMP-30 were added. The stirring speed was set to 400-500 r / min, and the mixture was magnetically stirred for 15 min. Then, the mixture was placed in an 80 ℃ vacuum drying oven and degassed at -0.085 to -0.095 MPa for 10-15 min. The mixture was poured into a mold, pre-cured at 100 ℃ for 1 h, then heated to 130 ℃ for 3 h, and then heated to 160 ℃ for 3 h. After cooling to room temperature, the mixture was demolded to obtain S5.

[0033] Example 6 The difference between Example 6 and Example 5 is that the curing agent used is MTHPA, the amount of curing agent is 48 g, and the curing procedure is to first pre-cure at 80 °C for 1 h, then heat to 120 °C for 2 h, and then heat to 140 °C for 4 h. The remaining steps are the same as in Example 5, and the resulting product is denoted as S6.

[0034] Example 7 The difference between Example 7 and Example 5 is that the curing agents used are MHHPA and MTHPA, the amount of curing agent used is 48 g, the mass ratio of MHHPA and MTHPA is 1:1, the curing procedure is to first pre-cure at 80 °C for 1 h, then heat to 120 °C for 2 h, and then heat to 140 °C for 4 h. The remaining steps are the same as in Example 5, and the resulting product is denoted as S7.

[0035] Example 8 The difference between Example 8 and Example 5 is that the curing agents used are MHHPA and MNA, the amount of curing agent used is 48 g, the mass ratio of MHHPA and MNA is 1:1, and the remaining steps are the same as in Example 5. The resulting product is denoted as S8.

[0036] The flexural mechanical properties, heat resistance, thermal expansion properties, and thermal conductivity of Examples 1 to 8 and the epoxy resin samples were tested, and the test results are shown below.

[0037] Figure 1These are SEM images of cross-sections of nano-aramid fibers and the nano-aramid fiber / polyphenylene ether / epoxy resin composite material from the examples. Figure 1 (a) is a SEM image of the cross-section of nano-aramid fiber and Figure 1 (b) SEM image of the cross-section of the nano-aramid fiber / polyphenylene ether / epoxy resin composite material. Figure 1 (b) It can be seen that the nano-aramid fibers are firmly embedded in the polyphenylene ether / epoxy resin blend and the two phases have good interfacial contact.

[0038] Table 1 shows the test results of flexural mechanical properties and heat resistance properties of the embodiments of the present invention and epoxy resin and polyphenylene ether / epoxy resin blends.

[0039] The test results above show that the flexural strength, flexural modulus, and heat resistance (characterized by dynamic thermomechanical analysis) of the samples in Examples 1-8 are continuously improved. Among them, Example 8 shows the best comprehensive performance, with its flexural strength and flexural modulus reaching 158.4 MPa and 3.81 GPa, respectively, which are 21.8% and 20.2% higher than those of epoxy resin. Its glass transition temperature is also increased to 164 ℃, showing better heat resistance.

[0040] Figure 2 These are the test results of the average thermal expansion coefficient of epoxy resin in Examples 1-8; the test conditions were: 30 ℃~180℃, under N2 atmosphere, with a heating rate of 5 ℃ / min. The samples were cuboid in shape, with length, width, and thickness of 25 mm, 5 mm, and 5 mm, respectively. Figure 2 Compared with pure epoxy resin, the coefficients of thermal expansion in Examples 1-8 all showed a decreasing trend, with the coefficient of thermal expansion in Example 8 decreasing to 65.3 ppm / K, which is about 31% and 32.8% lower than that in Example 1 and epoxy resin, respectively. The experimental results show that nano-aramid fibers can effectively suppress the thermal expansion of the resin matrix. The composite material prepared by this invention has excellent dimensional stability, can reduce the thermal stress of the encapsulated components, and ensure the normal operation of electronic products.

[0041] Figure 3 The results are the thermal conductivity test results of Examples 1-8 and epoxy resin, using a NETZSCH LFA447 laser thermal conductivity meter from Germany. Figure 3 The thermal conductivity of Examples 1-8 is continuously improved. Among them, the thermal conductivity of Example 8 reaches 0.248 W / m·K, which is 44.2% higher than that of epoxy resin.

[0042] The test results above show that, compared with epoxy resin, the samples obtained in Examples 1-8 exhibit significantly improved heat resistance, flexural mechanical properties, and thermal conductivity, while their coefficient of thermal expansion is significantly reduced. Among them, Example 8 demonstrates the best overall performance. Unlike the traditional "high-content inorganic filler" approach, this invention achieves the preparation of a fully organic epoxy composite material with low thermal expansion and high thermal conductivity by introducing only a low content of organic filler. This overcomes the bottleneck of the difficulty in simultaneously achieving "low thermal expansion" and "high toughness," providing a novel approach for the development of high-performance epoxy encapsulation materials.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and the above technical features can be combined in an appropriate manner. These improvements, modifications and combinations should all be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an all-organic epoxy resin composite material, characterized in that, The method includes: S1. Epoxy resin and phenolic hydroxyl polyphenylene ether are heated and melt-blended to obtain a composite system; S2. Add curing agent and catalyst to the composite system in sequence, heat and stir to react, and then degas under vacuum. Cast the resulting mixture into a mold, cure, cool and demold to obtain the all-organic epoxy resin composite material.

2. The method for preparing the all-organic epoxy resin composite material according to claim 1, characterized in that, The composite system also includes a nano-aramid fiber dispersion; S1 specifically includes: S11. Epoxy resin and phenolic hydroxyl polyphenylene ether are heated and melted together to obtain a polyphenylene ether / epoxy resin blend solution; S12. Add nano-aramid fibers to acetone and disperse them by strong ultrasonication to obtain a nano-aramid fiber dispersion. S13. The nano-aramid fiber dispersion is added dropwise to the polyphenylene ether / epoxy resin blend solution, magnetically stirred at room temperature, and then the acetone is evaporated to obtain the composite system.

3. The method for preparing the all-organic epoxy resin composite material according to claim 1, characterized in that, The curing agent is at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride; the amount of the curing agent is 60-85 wt% of the epoxy resin. The catalyst is 2,4,6-tris(dimethylaminomethyl)phenol, and the amount used is 0.5 to 3 wt% of the epoxy resin.

4. The method for preparing the all-organic epoxy resin composite material according to claim 2, characterized in that, The amount of phenolic hydroxyl polyphenylene ether used is 5 to 30 wt% of epoxy resin; the amount of nano-aramid fiber used is 0.1 to 0.4 wt% of epoxy resin.

5. The method for preparing the all-organic epoxy resin composite material according to claim 2, characterized in that, S11 specifically includes: stirring at a temperature of 80–120 °C and a rotation speed of 200–800 r / min for 4–8 h; The strong ultrasonic dispersion time in S12 is 1 to 2 hours.

6. The method for preparing the all-organic epoxy resin composite material according to claim 2, characterized in that, Specifically, S13 includes: magnetic stirring at room temperature for 1 to 4 hours; and evaporation of acetone by drying at 40 to 60 °C for 4 to 12 hours.

7. The method for preparing the all-organic epoxy resin composite material according to claim 1, characterized in that, S2 specifically includes: after adding curing agent and catalyst, reacting with magnetic stirring at 60-90 ℃ for 10-30 min, and then degassing at -0.085 to -0.095 MPa and 70-80 ℃ for 10-20 min.

8. The method for preparing the all-organic epoxy resin composite material according to claim 1, characterized in that, S2 also includes: cleaning the mold with anhydrous ethanol, sealing the small holes on the mold with vacuum grease after drying, then spraying a release agent and drying at 80 ℃ for 20-30 min; transferring the mixture into the mold, and after curing and cooling, demolding to obtain the all-organic epoxy resin composite material.

9. An all-organic epoxy resin composite material prepared by the method for preparing all-organic epoxy resin composite materials according to claims 1 to 8.

10. The application of the all-organic epoxy resin composite material according to claim 9 in the field of electronic packaging materials.

Images