Heat-conducting adhesive tape and preparation method thereof

Abstract

The invention relates to the technical field of heat-conducting materials, and discloses a heat-conducting adhesive tape and a preparation method thereof, and the heat-conducting adhesive tape comprises the following components: 50-70% by mass of a base material; the mass fraction of the heat-conducting filler is 10%-20%, and the size of the heat-conducting filler is 1-10 [mu] m; the functional molecule accounts for 5%-10% by mass; the mass fraction of the molecular bridging agent is 1%-5%, and the heat-conducting filler is one or more of graphene, fullerene or carbon nanotubes. The graphene, the fullerene, the heat-conducting molecular chain and the amino silane are combined for use, so that an efficient heat-conducting network is constructed, and the heat conductivity is remarkably improved. The particle size of graphene and the content of fullerene are optimized, the dispersity of the filler is enhanced, and the heat flow conduction effect is improved. The bridging effect of amino silane effectively reduces the interface thermal resistance and improves the heat flow transfer efficiency, and meanwhile, by optimizing the base material ratio and surface modification, the flexibility and high-temperature resistance of the adhesive tape are improved, and the adhesive tape is suitable for various high-temperature heat dissipation applications.

Description

Technical Field

[0001] The invention relates to the technical field of thermal conductive materials, in particular to a thermal conductive tape and a preparation method thereof. Background Art

[0002] Thermally conductive tapes are widely used in electronic devices, automobiles, and other fields that require heat dissipation. Their core function is to effectively conduct heat generated by the equipment through heat conduction to prevent the equipment from overheating. The thermal conductivity of existing thermally conductive tapes usually depends on filler materials, such as graphite, metal powder, and carbon nanotubes. Although these fillers have improved thermal conductivity to a certain extent, the dispersion of the fillers and the interfacial thermal resistance are still the key factors affecting the overall performance. Fillers with larger particle sizes or unevenly dispersed fillers can easily lead to interruptions in the thermal conduction path and increase in interfacial thermal resistance, which in turn affects the smooth conduction of heat flow.

[0003] The stability of thermally conductive tapes in high temperature environments is often limited, especially traditional materials are prone to aging or thermal expansion effects during long-term high-temperature use, resulting in thermal conductivity degradation. Such tapes are difficult to meet the requirements of modern high-power electronic products for long-term stable heat dissipation. For some electronic devices, thermally conductive tapes are required to have not only high thermal conductivity, but also good high-temperature stability.

[0004] Existing thermal conductive tapes usually ignore the balance between flexibility and high temperature resistance. Although traditional tapes can provide certain thermal conductivity, the rigidity of the substrate limits their application effect on complex surfaces, especially in application scenarios that require high flexibility and high heat dissipation efficiency. The performance of traditional tapes cannot fully meet the needs. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a thermally conductive tape and a preparation method thereof, which solve the problems of the prior art thermally conductive tape in terms of thermal conductivity, interface thermal resistance, high temperature resistance and flexibility.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A thermally conductive tape comprises the following components: Base material: 50% to 70% by mass; Thermal conductive filler: The mass percentage is 10% to 20%, and the size is 1 μm to 10 μm; Functional molecules: 5% to 10% by mass; Molecular bridging agent: The mass percentage is 1% to 5%.

[0007] Preferably, the thermally conductive filler is one or more of graphene, fullerene or carbon nanotube.

[0008] Preferably, the functional molecules are one or more of heat-conducting molecular chains or superconducting molecules.

[0009] Preferably, the molecular bridging agent is one or more of aminosilane or carboxyl polymer.

[0010] A method for preparing a thermally conductive tape comprises the following steps: S1. Weigh the substrate, thermal conductive filler, functional molecule and molecular bridging agent in proportion; S2. The raw material is added to an appropriate solvent and uniformly dispersed by an ultrasonic-assisted dispersion method; S3. The dispersed solution is subjected to desolventizing treatment to obtain a uniform tape slurry; S4. The tape slurry is applied to the metal substrate and hot pressed at a temperature of 100°C to 180°C; S5. The formed tape is cooled and cut into desired shapes.

[0011] Preferably, the frequency of the ultrasonic assisted dispersion in step S2 is 20kHz to 40kHz, and the power is 200W to 500W.

[0012] Preferably, in step S2, the solvent is N,N-dimethylformamide.

[0013] Preferably, the hot pressing temperature in step S4 is 120° C. to 180° C., and the pressing time is 5 minutes to 15 minutes.

[0014] Preferably, in step S4, the pressing pressure used during hot pressing is 5 MPa to 10 MPa.

[0015] Preferably, in step S4, the coating thickness of the tape slurry is 0.1 mm to 0.5 mm.

[0016] The present invention provides a thermal conductive tape and a preparation method thereof, which has the following beneficial effects: 1. The present invention uses a combination of graphene and fullerene, with heat-conducting molecular chains and aminosilane as molecular bridging agents, to construct an efficient heat-conducting network. Through this technical solution, the effect of significantly improving thermal conductivity is achieved. Compared with the technical solutions in the prior art that rely solely on graphene or fillers, the present invention solves the problems of uneven filler dispersion and excessive interface thermal resistance, and achieves more efficient heat conduction.

[0017] 2. The present invention optimizes thermal conductivity by precisely controlling the combination of graphene particle size and fullerene content. Compared with the prior art solution of using large-particle graphene, the present invention enhances the dispersibility of fillers by refining the particle size range, solves the defects of uneven dispersion of large-particle fillers and discontinuous heat flow conduction paths, and significantly improves the thermal conductivity of the tape.

[0018] 3. The present invention enhances the interfacial bonding force between the filler and the substrate through the bridging effect of aminosilane, thereby effectively reducing the interfacial thermal resistance. Compared with the solution using a lower molecular bridge agent in the prior art, the aminosilane used in the present invention is moderate, optimizes the interfacial bonding force, solves the problem of excessive interfacial thermal resistance, and significantly improves the heat flow transfer efficiency.

[0019] 4. The present invention ensures the flexibility and high temperature resistance of the tape by optimizing the ratio and surface modification of the polymer substrate. In the prior art, the flexibility and thermal stability of the substrate are often not balanced. The solution of the present invention successfully solves this problem, making the tape not only have excellent thermal conductivity, but also can be used stably in high temperature environments, and is suitable for a variety of high temperature heat dissipation applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure is a schematic flow chart of the steps for preparing the thermally conductive tape of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The embodiment of the present invention provides a thermally conductive tape, comprising the following components: Substrate: polyurethane / polysiloxane copolymer, with a mass percentage of 50% to 70%; Thermally conductive filler: one or more of graphene, fullerene or carbon nanotube, with a mass fraction of 10% to 20% and a size of 1 μm to 10 μm; Functional molecules: one or more of thermal conductive molecular chains or superconducting molecules, accounting for 5% to 10% by mass; Molecular bridging agent: one or more of aminosilane or carboxyl polymer, accounting for 1% to 5% by mass.

[0023] Please refer to the attached Figure 1 As part of this application, an embodiment of the present invention also provides a method for preparing a thermally conductive tape, comprising the following steps: S1. Weigh the substrate, thermal conductive filler, functional molecule and molecular bridging agent in proportion; S2. The raw material is added to an appropriate solvent and uniformly dispersed by an ultrasonic-assisted dispersion method; S3. The dispersed solution is subjected to desolventizing treatment to obtain a uniform tape slurry; S4. The tape slurry is applied to the metal substrate and hot pressed at a temperature of 100°C to 180°C; S5. The formed tape is cooled and cut into desired shapes.

[0024] To further illustrate the specific implementation of the present invention, several examples are provided below, which show how the ratios and preparation processes of different substrates, thermal conductive fillers, functional molecules and molecular bridging agents affect the performance of thermal conductive tapes. The examples show the preparation method of the present invention and the final product of the tape, which can clearly demonstrate the feasibility and effectiveness of the technical solution involved in the present invention. Example 1: The formula includes: base material: polyurethane / polysiloxane copolymer: 62%; thermal conductive filler: graphene: 16%; functional molecule: thermal conductive molecular chain: 8%; molecular bridging agent: aminosilane: 4%; solvent: N,N-dimethylformamide: 10%.

[0025] Steps and process parameters: First, put 62% of the polyurethane / polysiloxane copolymer into an appropriate amount of N,N-dimethylformamide and stir until completely dissolved. The solubility is 35g / 100mL. Add 16% of graphene and use ultrasonic treatment (power 400W, frequency 30kHz) for 40 minutes. At this time, ensure that the graphene is completely dispersed to avoid agglomeration. Add 8% of the thermal conductive molecular chain and continue stirring for 20 minutes to ensure that the molecular chain is evenly distributed in the solution. Add 4% of aminosilane, stir at 200r / min, and continue stirring for 30 minutes to allow the aminosilane to fully react with the substrate and enhance the interfacial bonding force. Apply the mixture to a stainless steel substrate with a coating thickness of 0.2mm. Hot press at 120°C, a pressure of 6MPa, and a hot pressing time of 8 minutes. After cooling, cut into the required size.

[0026] Through this step, the interface bonding force between the substrate and the thermal conductive filler is optimized, avoiding the problems of uneven filler distribution and excessive interface thermal resistance in the traditional technology. This embodiment can effectively improve the thermal conductivity and is particularly suitable for heat dissipation of high-power electronic products.

[0027] Example 2: The formula includes: base material: polyurethane / polysiloxane copolymer: 60%; thermal conductive filler: graphene: 18%; functional molecule: fullerene: 6%; molecular bridging agent: carboxyl polymer: 3%; solvent: N,N-dimethylformamide: 13%.

[0028] Steps and process parameters: Add 60% of polyurethane / polysiloxane copolymer to N,N-dimethylformamide with a solubility of 25g / 100mL and stir until completely dissolved. Add 18% of graphene and use ultrasonic treatment (power 300W, frequency 25kHz) for 35 minutes. Add 6% of fullerene and continue stirring for 20 minutes to ensure that the fullerene is evenly distributed. Add 3% of carboxyl polymer, stir at a rate of 250r / min, and stir for 30 minutes to ensure that the carboxyl polymer reacts fully with the filler. Apply the mixture to an aluminum alloy substrate with a coating thickness set to 0.15mm. Perform hot pressing, set the temperature to 150°C, the pressure to 8MPa, and the hot pressing duration to 6 minutes. After cooling to room temperature, cut into standard sizes.

[0029] This embodiment improves the synergistic effect between the thermal conductive molecular chain and the filler by introducing fullerene and carboxyl polymer. Compared with the traditional thermal conductive tape, this combination not only enhances the thermal conductivity, but also optimizes the high temperature stability of the material, solving the problems of easy degradation of the substrate and discontinuous heat conduction path in the prior art.

[0030] Example 3: The formula includes: base material: polyurethane / polysiloxane copolymer: 64%; thermal conductive filler: graphene: 14%; functional molecule: thermal conductive molecular chain: 10%; molecular bridging agent: aminosilane: 3%; solvent: N,N-dimethylformamide: 9%.

[0031] Steps and process parameters: First, dissolve 64% of the polyurethane / polysiloxane copolymer in N,N-dimethylformamide with a solubility of 30g / 100mL and stir until completely dissolved. Add 14% of graphene and use ultrasonic treatment (power 350W, frequency 30kHz) for 45 minutes to ensure that the graphene is completely dispersed in the solution. Add 10% of the thermal conductive molecular chain and continue stirring for 30 minutes to evenly distribute the molecular chains. Add 3% of aminosilane, stir at a rate of 250r / min, and stir for 45 minutes to enhance the bonding between the filler and the substrate. Apply the solution to the metal substrate with a coating thickness of 0.3mm. Perform hot pressing molding with the temperature set to 140°C, the pressure set to 7MPa, and the hot pressing time set to 7 minutes. Cool and cut into the required size.

[0032] This embodiment improves the dispersion effect of graphene by optimizing the solvent and ultrasonic treatment conditions, effectively avoiding the problem of filler aggregation. While enhancing thermal conductivity, combined with the use of aminosilane bridging agent, the problem of excessive interface thermal resistance is solved, ensuring smoother heat flow transfer and improving the overall performance of the tape.

[0033] Example 4: The formula includes: base material: polyurethane / polysiloxane copolymer: 58%; thermal conductive filler: graphene: 20%; functional molecule: thermal conductive molecular chain: 8%; molecular bridging agent: aminosilane: 5%; solvent: N,N-dimethylformamide: 9%.

[0034] Steps and process parameters: Add 58% of polyurethane / polysiloxane copolymer to N,N-dimethylformamide and dissolve until completely transparent with a solubility of 33g / 100mL. Add 20% of graphene and use ultrasonic treatment (power 450W, frequency 35kHz) for 50 minutes to ensure that the graphene is fully dispersed. Add 8% of thermal conductive molecular chains and continue stirring for 40 minutes to ensure that the thermal conductive molecular chains are evenly distributed. Add 5% of aminosilane, stir at 250r / min, and continue stirring for 50 minutes to ensure that the aminosilane reacts with the filler and substrate. Apply the mixed solution on the aluminum alloy substrate, and the coating thickness is controlled at 0.25mm. Perform hot pressing, set the temperature to 160℃, the pressure to 8MPa, and the continuous hot pressing time to 10 minutes. After cooling, cut to the required size.

[0035] This embodiment ensures a significant improvement in thermal conductivity and avoids filler agglomeration through optimized ultrasonic treatment and ultra-high graphene content. The addition of aminosilane enhances the bonding force between the filler and the substrate, solves the defect of excessively high interface thermal resistance in the prior art, and improves the overall stability and thermal conduction efficiency of the thermal conductive tape.

[0036] Example 5: The formula includes: base material: polyurethane / polysiloxane copolymer: 65%; thermal conductive filler: graphene: 12%; functional molecule: fullerene: 10%; molecular bridging agent: carboxyl polymer: 3%; solvent: N,N-dimethylformamide: 10%.

[0037] Steps and process parameters: First, mix 65% of the polyurethane / polysiloxane copolymer with N,N-dimethylformamide, set the solubility to 28g / 100mL, and stir until completely dissolved. Add 12% of graphene and use ultrasonic treatment (power 400W, frequency 30kHz) for 45 minutes to ensure that the graphene is evenly dispersed. Add 10% of fullerene and stir for 30 minutes to ensure that the molecules are evenly distributed. Add 3% of the carboxyl polymer, stir at 250r / min, and continue stirring for 45 minutes to ensure that the carboxyl polymer reacts fully with the filler and substrate. The solution is evenly coated on the aluminum substrate with a coating thickness of 0.2mm. Perform hot pressing, set the temperature to 150°C, the pressure to 9MPa, and the hot pressing time to 8 minutes. Cool to room temperature and cut into the desired shape and size.

[0038] In order to further verify the superiority of the present invention, the following comparative examples are used to compare the differences in thermal conductivity, preparation process, etc. between the prior art and the thermally conductive tape of the present invention. By setting up different comparison groups, we compare the thermally conductive tape of the present invention with the conventional thermally conductive tape commonly found on the market to demonstrate the advantages of the present invention. The comparative experiment is helpful to evaluate the technical advantages of the present invention in practical applications and its improvement effects.

[0039] Comparative Example 1: Comparison based on fine-tuning of graphene content.

[0040] The formula includes: polyurethane / polysiloxane copolymer: 60%; graphene: 14%; thermal conductive molecular chain: 8%; aminosilane: 4%; N,N-dimethylformamide: 14%.

[0041] Comparative Example Steps and Process Parameters: Add 60% of polyurethane / polysiloxane copolymer to N,N-dimethylformamide and stir until completely dissolved, with a solubility of 32g / 100mL. Add 14% of graphene and use ultrasonic treatment (power 350W, frequency 30kHz) for 40 minutes. This step is similar to Example 1, but the graphene content is reduced by 2%, so that the filler concentration is low. Add 8% of thermal conductive molecular chains and continue stirring for 25 minutes to ensure that the molecular chains are evenly distributed. Add 4% of aminosilane, stir at a rate of 200r / min, and stir for 30 minutes. Apply the mixture to a stainless steel substrate with a coating thickness of 0.2mm. Hot pressing is performed at 120°C, a pressure of 6MPa, and a hot pressing time of 8 minutes. After cooling, cut into the desired size.

[0042] Difference: Compared with Example 1, the graphene content of this comparative example is reduced by 2%. In this comparative example, the graphene content is lower than that of Example 1, which may lead to poor dispersion of the thermal conductive filler and may affect the thermal conductivity of the tape. This comparative experiment is intended to compare the effect of graphene content on the thermal conductivity of the tape, highlighting the innovation of the present invention of improving thermal conductivity by adding an appropriate amount of graphene.

[0043] Comparative Example 2: Comparison of fullerene removal.

[0044] The formula includes: polyurethane / polysiloxane copolymer: 62%; graphene: 18%; aminosilane: 4%; N,N-dimethylformamide: 16%.

[0045] Comparative example steps and process parameters: 62% of polyurethane / polysiloxane copolymer is dissolved in N,N-dimethylformamide with a solubility of 30g / 100mL. Add 18% of graphene and use ultrasonic treatment (power 350W, frequency 30kHz) for 45 minutes to ensure that the graphene is fully dispersed. Add 4% of aminosilane, stir at a rate of 250r / min, and stir for 30 minutes. Evenly apply the solution to the metal substrate with a coating thickness of 0.25mm. Perform hot pressing molding with a set temperature of 130°C, a pressure of 7MPa, and a hot pressing time of 6 minutes. Cool and cut into the required size.

[0046] Difference: Compared with Example 2, this comparative example removes fullerene and only retains components such as graphene and aminosilane. Fullerene, as a functional molecule, has a significant effect on improving thermal conductivity. Removing fullerene will reduce the thermal conductivity path of the tape and reduce thermal conductivity. This comparative experiment is used to verify the contribution of fullerene to the overall thermal conductivity of the thermally conductive tape.

[0047] Comparative Example 3: reducing the dosage of aminosilane.

[0048] The formula includes: polyurethane / polysiloxane copolymer: 62%; graphene: 16%; thermal conductive molecular chain: 8%; aminosilane: 2%; N,N-dimethylformamide: 12%.

[0049] Comparative example steps and process parameters: 62% of the polyurethane / polysiloxane copolymer was dissolved in N,N-dimethylformamide with a solubility of 30g / 100mL. 16% of graphene was added and ultrasonic treatment (power 350W, frequency 30kHz) was used for 40 minutes. 8% of the thermal conductive molecular chain was added and stirring was continued for 30 minutes. The proportion of aminosilane was reduced to 2%, and stirring was continued at 250r / min for 30 minutes to ensure that the aminosilane was well bonded to the filler and the substrate. The mixture was applied to the metal substrate with a coating thickness of 0.2mm. Hot pressing was performed with the temperature set to 120°C, the pressure to 6MPa, and the hot pressing time to 7 minutes. After cooling, it was cut into the desired size.

[0050] Difference: This comparative experiment reduces the proportion of aminosilane from 4% to 2%. As a molecular bridging agent, aminosilane is used to enhance the bonding force between the filler and the substrate and reduce the interfacial thermal resistance. Reducing the amount of aminosilane may result in insufficient interfacial bonding and increased interfacial thermal resistance, thus affecting the thermal conductivity. This comparative experiment is used to verify the key role of aminosilane in improving the thermal conductivity of thermal conductive tapes.

[0051] Comparative Example 4: Removing the heat-conducting molecular chains.

[0052] The formula includes: polyurethane / polysiloxane copolymer: 65%; graphene: 12%; fullerene: 8%; aminosilane: 5%; N,N-dimethylformamide: 10%.

[0053] Comparative example steps and process parameters: 65% of the polyurethane / polysiloxane copolymer was dissolved in N,N-dimethylformamide with a solubility of 28g / 100mL. 12% of graphene was added and ultrasonic treatment (power 450W, frequency 35kHz) was used for 50 minutes. 8% of fullerene was added and stirring was continued for 30 minutes to ensure that the fullerene was evenly distributed. The proportion of aminosilane was set to 5%, stirring was continued at 250r / min for 40 minutes. The mixture was evenly coated on an aluminum alloy substrate with a coating thickness of 0.25mm. Hot pressing was performed at a temperature of 150°C, a pressure of 9MPa, and a hot pressing time of 8 minutes. Cut into the required size after cooling.

[0054] Difference: This comparative example removes the thermal conductive molecular chain, leaving only graphene, fullerene and aminosilane. The thermal conductive molecular chain improves the efficiency of the heat conduction path through its molecular structure, and its removal may lead to a decrease in the thermal conduction efficiency. This comparative experiment aims to verify the contribution of the thermal conductive molecular chain in improving the thermal conductivity of the tape and highlight its unique role in the multi-component design.

[0055] Comparative Example 5: Adjusting the graphene particle size.

[0056] The formula includes: polyurethane / polysiloxane copolymer: 62%; graphene: 16%; thermal conductive molecular chain: 8%; aminosilane: 4%; N,N-dimethylformamide: 10%.

[0057] Comparative example steps and process parameters: Dissolve 62% of polyurethane / polysiloxane copolymer with N,N-dimethylformamide with a solubility of 35g / 100mL and stir until completely dissolved. Add 16% of graphene and treat with ultrasonic wave (power 350W, frequency 30kHz) for 45 minutes. The graphene particle size used in this comparison is 10μm, which is larger than the 5μm in the embodiment. Add 8% of thermal conductive molecular chains and stir for 30 minutes to ensure uniform distribution of molecules. Add 4% of aminosilane, stir at 250r / min, and continue stirring for 40 minutes. Apply the mixture to a metal substrate with a coating thickness of 0.2mm. Perform hot pressing molding with the temperature set to 130°C, the pressure to 7MPa, and the hot pressing time for 7 minutes. After cooling, cut into the desired size.

[0058] Difference: Compared with the graphene particle size of 1μm to 5μm in the embodiment, this comparative example uses a larger graphene particle size (10μm). A larger particle size may lead to poor dispersion of graphene and affect thermal conductivity. The purpose of this comparative experiment is to verify the effect of particle size on filler dispersion and thermal conductivity, highlighting the optimized design of graphene particle size in the present invention.

[0059] In order to verify the performance of the thermally conductive tape of the present invention, the present invention has carried out a series of test experiments. These experiments include testing of multiple factors such as thermal conductivity, thickness, and hot pressing process of the tape to evaluate the impact of different preparation conditions on the final product. Through the test experiments, the technical effects of the present invention can be objectively presented, and the improvement effect of the preparation method on thermal conductivity can be verified. The experimental data will provide a reliable scientific basis for the technical solution of the present invention, ensuring its feasibility and superiority in practical applications.

[0060] Experiment 1: Effect of graphene content on thermal conductivity.

[0061] Experimental description: The main purpose of this experiment is to compare the effect of graphene content on thermal conductivity in Example 1 and Comparative Example 1. By testing the thermal conductivity of thermally conductive tapes with different graphene contents, the role of graphene as a thermally conductive filler is evaluated.

[0062] Experimental steps: Sample preparation: According to the formula of Example 1 and Comparative Example 1, prepare tape samples respectively. Take a certain mass of polyurethane / polysiloxane copolymer, add it to N,N-dimethylformamide and dissolve it to ensure complete dissolution. Add a corresponding proportion of graphene, which is 16% according to Example 1 and 14% for Comparative Example 1. The graphene is evenly dispersed in the solution by ultrasonic treatment (power 350W, frequency 30kHz, treatment time 40 minutes). Add thermal conductive molecular chains and aminosilane, and stir until the solution is uniform. Apply the mixed solution to a stainless steel substrate with a coating thickness of 0.2mm. The coated sample is hot pressed, the temperature is set to 120°C, the pressure is 6MPa, and the hot pressing time is 8 minutes. After cooling, cut the tape sample according to the required size to ensure that the sample size is consistent for easy testing.

[0063] Thermal conductivity test: Thermal conductivity test was performed using a heat flow meter (Thermal Conductivity Tester). The size of each sample was set to 5mm×5mm to ensure a stable test environment. The test temperature range was set to 25℃ to 150℃. The thermal conductivity of the samples was tested to compare the effects of different graphene contents.

[0064] Data Recording and Analysis: Record the thermal conductivity of each test sample at different temperatures.

[0065] By comparing the experimental data, the contribution of graphene content to the thermal conductivity of the tape was evaluated.

[0066] Experimental data: Table 1: Comparison of thermal conductivity data in Experiment 1: It can be seen from the experimental results that the increase in graphene content significantly improves the thermal conductivity of the tape. In Example 1, the content of graphene is 16%, and its thermal conductivity shows higher values ​​at all temperature points compared to 14% in Comparative Example 1. This shows that the increase of graphene as a thermally conductive filler can effectively improve the thermal conductivity of the tape. According to the mechanism of heat conduction, graphene has a higher thermal conductivity, and its two-dimensional structure can provide a more continuous and efficient heat conduction path. Through ultrasonic treatment, the dispersion of graphene is optimized, and the contact between fillers is closer, thereby reducing the interfacial thermal resistance and enhancing the overall thermal conductivity.

[0067] In addition, as a nanoscale thermal conductive material, the size and distribution state of graphene have an important influence on thermal conductivity. By increasing the proportion of graphene in Example 1, the thermal conductivity path is more fully constructed compared to Comparative Example 1. As we know, the thermal conductivity of graphene is affected by its particle size, dispersibility and interfacial bonding with the substrate. Experimental data show that 16% of graphene content provides a stronger thermal conductivity path compared to 14%, while also reducing the possible agglomeration of fillers, thereby ensuring smooth conduction of heat flow.

[0068] Finally, these experimental data further verify the direct effect of graphene content on the thermal conductivity of thermally conductive tape. We compared the thermal conductivity of different graphene contents through the heat flow meter used in the experiment, and clearly showed the improvement in thermal conductivity brought about by the increase in graphene content. This finding provides a basis for selecting the appropriate filler amount in practical applications, especially in high-power electronic products or application scenarios that require efficient heat dissipation.

[0069] Experiment 2: Effect of removing fullerenes on thermal conductivity.

[0070] Experimental description: The purpose of this experiment is to verify the contribution of fullerene in improving thermal conductivity by removing fullerene. As a functional molecule, fullerene can play a significant role in the thermal conductivity path. This experiment compares Example 2 with Comparative Example 2 to evaluate the effect of removing fullerene on the thermal conductivity of the tape.

[0071] Experimental steps: Sample preparation: According to the formula of Example 2 and Comparative Example 2, samples were prepared respectively. The fullerene content in Example 2 is 6%, while the fullerene is removed in Comparative Example 2, and the other components remain unchanged. Take a certain amount of polyurethane / polysiloxane copolymer, add it to an appropriate amount of N,N-dimethylformamide to dissolve, and ensure complete dissolution. Add fullerene (Example 2) or skip adding fullerene (Comparative Example 2). Ultrasonic treatment (power 350W, frequency 30kHz, treatment time 45 minutes) is used to ensure uniform distribution of graphene and thermal conductive molecular chains. Add aminosilane and stir evenly to ensure sufficient chemical reaction. The coating thickness is set to 0.25mm to ensure uniform coating. The coated sample is hot pressed, the temperature is set to 150°C, the pressure is 8MPa, and the hot pressing time is 6 minutes. After cooling is completed, cut the tape sample and keep the size consistent for testing.

[0072] Thermal conductivity test: Use a heat flow meter to test the thermal conductivity of the samples. Ensure that the sample size is consistent during the test. The test temperature range is set at 50°C to 100°C. By testing the thermal conductivity of the samples, compare the effect of the presence or absence of fullerene on the thermal conductivity. Measure the thermal conductivity of each sample to ensure data consistency.

[0073] Data recording and analysis: Compare experimental data and record the difference in thermal conductivity of samples with and without fullerenes. Combine temperature and heat flow tests to analyze the role of fullerenes in improving thermal conductivity paths.

[0074] Table 2: Data comparison of the effect of fullerene on thermal conductivity The experimental results show that the addition of fullerene significantly improves the thermal conductivity of the thermally conductive tape. In Example 2, the introduction of fullerene makes the thermal conductivity higher than that of Comparative Example 2 at all temperature points. After removing fullerene, the decrease in thermal conductivity shows that fullerene, as a functional molecule, plays an important role in improving the efficiency of thermal conduction. This result verifies the unique function of fullerene in the thermal conduction path, which enhances the connection between the filler and the substrate through intermolecular interactions and promotes the rapid conduction of heat.

[0075] The molecular structure of fullerene has high thermal conductivity. By forming a synergistic effect with graphene and other thermally conductive fillers, a more efficient thermal conductive network is constructed. The introduction of fullerene allows heat to be transferred with higher efficiency at the microscopic level. This molecular chain enhancement effect no longer exists when fullerene is removed, resulting in a significant decrease in thermal conductivity. Compared with traditional tapes that rely solely on graphene or other fillers, the unique contribution of fullerene provides more heat conduction channels for the thermal path, thereby improving the overall thermal conductivity.

[0076] When analyzing the mechanism of fullerene action, we can see the role of fullerene's special molecular structure in thermal conductivity. It forms a tight thermal bridge with other fillers through the intermolecular π-π stacking effect, ensuring that the heat flow can flow quickly. The experimental results also show that the introduction of fullerene can not only improve the thermal conductivity efficiency, but also maintain stable thermal conductivity at high temperatures. After removing fullerene, the decrease in thermal conductivity reflects the importance of this molecule to heat flow conduction, further proving the key role of fullerene in thermal conductive tapes.

[0077] Experiment 3: Effect of aminosilane dosage on thermal conductivity.

[0078] Experimental description: This experiment aims to explore the effect of aminosilane content on the thermal conductivity of thermally conductive tape. As a molecular bridging agent, aminosilane can enhance the bonding force between the filler and the substrate, thereby reducing the interfacial thermal resistance and improving the thermal conduction effect. By comparing the amount of aminosilane used in Example 3 and Comparative Example 3, its effect on thermal conductivity is evaluated.

[0079] Experimental steps: Sample preparation: Prepare the tape according to the formula of Example 3 and Comparative Example 3. The aminosilane content in Example 3 is 3%, and the aminosilane content in Comparative Example 3 is 2%. Take an appropriate amount of polyurethane / polysiloxane copolymer and dissolve it in N,N-dimethylformamide to ensure complete dissolution. Add graphene and thermal conductive molecular chains, and use ultrasonic treatment (power 350W, frequency 30kHz, treatment time 40 minutes) to ensure uniform dispersion. According to the different aminosilane contents, 3% (Example 3) and 2% (Comparative Example 3) of aminosilane are added respectively, and stirred until the reaction is complete. The mixed solution is applied to an aluminum alloy substrate, and the coating thickness is controlled at 0.2mm. Hot pressing is performed at 150°C, the pressure is 8MPa, and the hot pressing time is set to 7 minutes. After the sample is cooled, it is cut into the required size to ensure sample consistency.

[0080] Thermal conductivity test: Use a heat flow meter to test the thermal conductivity of the sample, and the test temperature range is set to 50℃ to 100℃. Measure the thermal conductivity of each sample to ensure the accuracy of the test.

[0081] Data recording and analysis: Record the thermal conductivity data of Example 3 and Comparative Example 3 at different temperatures.

[0082] Analyze the effect of aminosilane dosage on the thermal conductivity of the tape.

[0083] Table 3: Data comparison of the effect of aminosilane dosage on thermal conductivity Through the analysis of experimental data, we found that the amount of aminosilane used has a significant effect on the thermal conductivity of the tape. In Example 3, the content of aminosilane is 3%, and at each temperature point, its thermal conductivity is significantly higher than the 2% aminosilane content in Comparative Example 3. This shows that increasing the amount of aminosilane appropriately can significantly improve the thermal conductivity of the tape. As a molecular bridging agent, aminosilane can form a tighter chemical bond between the filler and the substrate, reduce the interfacial thermal resistance, and thus improve the thermal conductivity.

[0084] The mechanism of action of aminosilane molecular bridging agent is closely related to its molecular structure. It forms chemical bonds with the filler surface through siloxy groups, improves the dispersion of the filler, and reduces the interfacial thermal resistance. This effect is more obvious at higher aminosilane concentrations. A higher aminosilane content can enhance the heat conduction path at the interface, allowing heat flow to pass more smoothly, thereby improving thermal conductivity. In the experiment, when the aminosilane content was 3%, the intermolecular interaction force and the bonding force between the filler and the substrate were effectively enhanced.

[0085] For comparative example 3 with a lower aminosilane content, although the interfacial bonding force is enhanced, there is still a high interfacial thermal resistance, which directly affects the thermal conduction efficiency. It can be seen that the adjustment of the amount of aminosilane has an important influence on the thermal conductivity. Too low an amount of aminosilane cannot fully optimize the interface structure, resulting in the thermal conductivity failing to reach the optimal level. The experimental results further verify the key role of aminosilane as a bridging agent in improving the thermal conductivity of the tape.

[0086] Experiment 4: Effect of heat-conducting molecular chains on thermal conductivity.

[0087] Experimental description: This experiment aims to study the effect of thermal conductive molecular chains on the thermal conductivity of the tape. As a thermal conductive auxiliary agent, the thermal conductive molecular chain not only enhances thermal conduction, but also provides auxiliary support for the thermal conduction path between the filler and the substrate. This experiment evaluates the contribution of thermal conductive molecular chains to thermal conductivity by comparing the presence or absence of thermal conductive molecular chains in Example 4 and Comparative Example 4.

[0088] Experimental steps: Sample preparation: Samples were prepared according to the formulas of Example 4 and Comparative Example 4. The content of the thermally conductive molecular chain in Example 4 was 10%, while Comparative Example 4 removed the thermally conductive molecular chain and only used graphene, fullerene and aminosilane. The polyurethane / polysiloxane copolymer was added to N,N-dimethylformamide and stirred until completely dissolved. Graphene and fullerene were added to the solution, and ultrasonic treatment (power 400W, frequency 30kHz, treatment time 50 minutes) was used to ensure uniform dispersion. 10% thermally conductive molecular chain (Example 4) was added or the thermally conductive molecular chain (Comparative Example 4) was omitted and stirred until the reaction was uniform. Finally, aminosilane was added to ensure sufficient bridging between the filler and the substrate. The solution was coated on an aluminum alloy substrate, and the coating thickness was controlled to be 0.25 mm. Hot pressing was performed at 140°C, the pressure was set to 7MPa, and the hot pressing time was 8 minutes. After the sample was cooled, it was cut into the required size to ensure consistent size.

[0089] Thermal conductivity test: Use a heat flow meter to test the thermal conductivity of the sample, and the test temperature range is set to 50℃ to 100℃. Measure the thermal conductivity of each sample, record the data and ensure the stability of the test.

[0090] Data recording and analysis: Record the thermal conductivity data of Example 4 and Comparative Example 4 at different temperatures.

[0091] The thermal conductivity of the two is compared, and the contribution of the introduction of thermal conductive molecular chains to the thermal conductivity of the tape is analyzed.

[0092] Table 4: Data comparison of the effect of thermal conductive molecular chains on thermal conductivity From the experimental results, the addition of thermally conductive molecular chains significantly improves the thermal conductivity of the thermally conductive tape. The content of thermally conductive molecular chains in Example 4 is 10%, and at each test temperature, the thermal conductivity is generally higher than that of the tape without thermally conductive molecular chains in Comparative Example 4. This result shows that the thermally conductive molecular chain plays a vital role in improving the efficiency of thermal conduction. It not only provides more transfer channels for heat flow, but also promotes the efficient flow of heat by enhancing intermolecular interactions.

[0093] The mechanism of action of the thermal conductive molecular chain can be explained at the molecular level. The thermal conductive molecular chain is usually composed of molecules with high thermal conductivity, which can form a stable heat conduction network with other thermal conductive fillers through interactions such as π-π stacking and hydrogen bonding. Due to the characteristics of its molecular structure, the thermal conductive molecular chain provides a low thermal resistance, continuous conduction path for heat flow, which plays a significant role in improving the efficiency of thermal conduction. After removing the thermal conductive molecular chain, the heat conduction path between the fillers will become discontinuous, and the conduction efficiency of the heat flow will be significantly reduced, resulting in a decrease in thermal conductivity.

[0094] Further analysis shows that the introduction of thermal conductive molecular chains not only enhances the conduction path of heat flow, but also enhances the overall stability of the material. In the experiment, with the increase in the content of thermal conductive molecular chains, the heat flow transfer rate and thermal conductivity both showed a trend of gradual improvement. This change is directly related to the efficient heat transfer characteristics of the thermal conductive molecular chains. In contrast, in Comparative Example 4 where the thermal conductive molecular chains are removed, although graphene and fullerene still provide thermal conductivity, the lack of the help of thermal conductive molecular chains results in the interruption of the conduction path of the heat flow, and the thermal conductivity cannot reach the ideal level. Experiment 5: Effect of graphene particle size on thermal conductivity.

[0095] Experimental description: This experiment aims to explore the effect of graphene particle size on the thermal conductivity of thermally conductive tape. The experiment evaluates the effect of particle size on thermal conductivity by comparing Example 5 (using graphene with smaller particle size) and Comparative Example 5 (using graphene with larger particle size). The particle size of graphene has an important influence on its dispersibility and thermal conductivity. This experiment will help confirm the role of particle size on the overall thermal conductivity of the tape.

[0096] Experimental steps: Sample preparation: Samples were prepared according to the formulas of Example 5 and Comparative Example 5. The graphene particle size used in Example 5 was 1 μm to 5 μm, while the graphene particle size used in Comparative Example 5 was 10 μm. First, the polyurethane / polysiloxane copolymer was added to N,N-dimethylformamide and stirred until completely dissolved. According to the graphene of different particle sizes, the corresponding graphene powder was added. Example 5 used graphene with a particle size of 1 μm to 5 μm, while Comparative Example 5 used graphene with a particle size of 10 μm. The graphene was ultrasonically treated (power 350 W, frequency 30 kHz, treatment time 45 minutes) to ensure uniform dispersion of the graphene. Heat-conducting molecular chains and aminosilane were added to ensure that the components were fully mixed. The mixed solution was applied to an aluminum alloy substrate with a coating thickness of 0.25 mm. Hot pressing was performed at 140°C, the pressure was 7 MPa, and the hot pressing time was 8 minutes. After cooling was completed, the tape sample was cut according to the standard size.

[0097] Thermal conductivity test: Each sample is tested for thermal conductivity using a heat flow meter, with the test temperature range set at 50°C to 100°C. The thermal conductivity of each sample will be measured at different temperatures to ensure consistent test conditions.

[0098] Data recording and analysis: Record the thermal conductivity of Example 5 and Comparative Example 5 at each test temperature. Analyze the effect of particle size on the thermal conductivity of the tape, and verify the contribution of particle size to thermal conductivity through data comparison.

[0099] Table 5: Data comparison of the effect of graphene particle size on thermal conductivity Through the analysis of the experimental data, it is obvious that the graphene with smaller particle size (1 μm to 5 μm) is better than the graphene with larger particle size (10 μm) in thermal conductivity. The small particle size graphene in Example 5 shows higher thermal conductivity at each test temperature. This shows that the graphene with smaller particle size performs better in dispersibility and can more effectively form a continuous heat conduction channel in the substrate, thereby improving the heat conduction efficiency.

[0100] The effect of graphene particle size on thermal conductivity can be explained from its dispersibility and the continuity of the thermal conduction path. Smaller particle size means that graphene can be more evenly distributed in the solution, avoiding the agglomeration of large-particle graphene. Although larger graphene particles (such as 10μm particle size) have higher thermal conductivity, they tend to aggregate into lumps during the dispersion process, which leads to discontinuity of the heat conduction path, thereby affecting the heat transfer efficiency. In contrast, smaller-particle graphene can form a more stable network with other thermally conductive fillers and substrates, reducing heat loss.

[0101] From the perspective of molecular dynamics, the two-dimensional structure of graphene has a great contribution to thermal conductivity. Graphene with small particle size not only enhances the contact area between the substrate and the filler, but also reduces the interfacial thermal resistance, further optimizing the heat conduction path. In the experiment, the addition of graphene with smaller particle size in Example 5 improves the heat conduction efficiency by enhancing the dispersibility and network connection between the fillers. The experimental results not only show the key role of particle size in thermal conductivity, but also further verify the advantages of graphene as a thermally conductive filler, especially its application potential in the design of thermally conductive materials.

[0102] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A thermally conductive tape, characterized in that: Includes the following components: Substrate: 50% to 70% by mass; Thermal conductive filler: The mass percentage is 10% to 20%, and the size is 1μm to 10μm; Functional molecules: 5% to 10% by mass; Molecular bridging agent: The mass percentage is 1% to 5%.

2. A thermally conductive tape according to claim 1, characterized in that: The thermal conductive filler is one or more of graphene, fullerene or carbon nanotube.

3. A thermally conductive tape according to claim 1, characterized in that: The functional molecules are one or more of heat-conducting molecular chains or superconducting molecules.

4. The thermally conductive tape according to claim 1, characterized in that: The molecular bridging agent is one or more of aminosilane or carboxyl polymer.

5. A method for preparing a thermally conductive tape, characterized in that: A thermally conductive adhesive tape as claimed in any one of claims 1 to 4, comprising the following steps: S1. Weigh the substrate, thermal conductive filler, functional molecule and molecular bridging agent in proportion; S2. The raw material is added to an appropriate solvent and uniformly dispersed by an ultrasonic-assisted dispersion method; S3. The dispersed solution is subjected to desolventizing treatment to obtain a uniform tape slurry; S4. The tape slurry is applied to the metal substrate and hot pressed at a temperature of 100°C to 180°C; S5. The formed tape is cooled and cut into desired shapes.

6. The method for preparing a thermally conductive tape according to claim 5, characterized in that: The frequency of the ultrasonic wave-assisted dispersion in step S2 is 20kHz to 40kHz, and the power is 200W to 500W.

7. The method for preparing a thermally conductive tape according to claim 5, characterized in that: In step S2, the solvent is N,N-dimethylformamide.

8. The method for preparing a thermally conductive tape according to claim 5, characterized in that: The hot pressing temperature in step S4 is 120° C. to 180° C., and the pressing time is 5 minutes to 15 minutes.

9. The method for preparing a thermally conductive tape according to claim 5, characterized in that: In the step S4, the pressing pressure used during hot pressing is 5 MPa to 10 MPa.

10. The method for preparing a thermally conductive tape according to claim 5, characterized in that: In the step S4, the coating thickness of the tape slurry is 0.1 mm to 0.5 mm.

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