Carbon nano tube and graphite mixed heat-conducting coating for heat dissipation of power control cabinet and coating process of carbon nano tube and graphite mixed heat-conducting coating

Abstract

The invention discloses a carbon nanotube and graphite mixed heat-conducting coating for heat dissipation of a power control cabinet and a coating process. The heat-conducting coating is prepared from the following raw material components: carbon nanotubes, graphite powder, epoxy resin, a plasticizer, a curing agent and a dispersing agent. The invention has the beneficial effects of excellent heat dissipation performance, enhanced adhesive force, significantly improved high temperature resistance, improved long-term stability of equipment, environmental protection and energy saving.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal conductive coatings, in particular to a carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in a power control cabinet and a coating process thereof. Background Art

[0002] With the development of high power density and miniaturization of power control cabinets, heat dissipation has become a key design issue. The electronic components inside the power control cabinet often generate high heat due to long-term high-power load operation. If heat is not dissipated in a timely and effective manner, the excessive temperature of the equipment may cause electronic component failure, system instability, and even equipment failure. Therefore, the heat dissipation design of the power control cabinet is crucial to its performance and reliability.

[0003] Existing power control cabinet cooling solutions mostly use traditional cooling methods such as air cooling, heat sinks, or heat pipes. However, these methods generally have the following defects:

[0004] Low heat dissipation efficiency: Traditional heat dissipation methods cannot effectively meet the heat dissipation requirements under high power density and high load conditions;

[0005] Size and noise issues: Air-cooled heat sinks are usually large and produce loud noise under high load;

[0006] Difficult to maintain: The heat dissipation device is complicated to maintain and clean, and is easily affected by dust and dirt;

[0007] Carbon nanotubes (CNTs) and graphite, as new thermal conductive materials, have attracted widespread attention in the field of electronic component heat dissipation due to their excellent thermal conductivity. CNTs have extremely strong thermal conductivity, and graphite powder can not only enhance thermal conductivity but also regulate the fluidity of the coating and reduce the agglomeration of thermal conductive fillers. However, how to efficiently apply these materials to coatings and ensure their stability is a major challenge in existing technologies. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a carbon nanotube and graphite mixed thermal conductive coating for power control cabinet heat dissipation, including the following raw material components: carbon nanotubes, graphite powder, epoxy resin, plasticizer, curing agent, and dispersant.

[0009] A carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in power control cabinets, comprising, by weight: 6-8g carbon nanotubes; 34-36g graphite powder; 39-41g epoxy resin; 3-5g plasticizer; 5-7g curing agent; and 1-3g dispersant. The ratio of carbon nanotubes to graphite is typically 7:35.

[0010] As a further supplement to the technical solution, the thermal conductive coating comprises, by weight: 7 g of carbon nanotubes; 35 g of graphite powder; 40 g of epoxy resin; 4 g of plasticizer; 6 g of curing agent; and 2 g of dispersant.

[0011] As a further supplement to the technical solution, the carbon nanotubes are multi-walled carbon nanotubes.

[0012] As a further supplement to the present technical solution, the graphite powder is graphite powder with a particle size of less than 10 μm.

[0013] As a further supplement to this technical solution, the plasticizer is dibutyl phthalate.

[0014] As a further supplement to this technical solution, the curing agent is tetrahydrofuran.

[0015] As a further supplement to this technical solution, the dispersant is polyvinyl alcohol.

[0016] A coating process for a carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in a power control cabinet comprises the following steps:

[0017] Step 1: Surface treatment;

[0018] Before coating, the PCBs and other important electrical components inside the power control cabinet must be surface treated to ensure they are free of oil, dust, and other impurities to ensure coating adhesion and uniformity. The cleaned PCBs must be dried, usually at a temperature of 50°C to 60°C for 10-15 minutes to ensure no moisture remains on the surface. Once the surface is clean and dry, the coating process can proceed to the next step.

[0019] Step 2: Mix ingredients and stir;

[0020] First, according to the predetermined formula, the raw materials of carbon nanotubes, graphite powder, epoxy resin, plasticizer, curing agent and dispersant are prepared;

[0021] When mixing, carbon nanotubes and graphite powder should be added to the epoxy resin matrix and mixed using a high shear mixer. The stirring speed and time should be adjusted according to the specific coating requirements, usually 3000 rpm and a stirring time of 10-15 minutes.

[0022] After mixing is complete, add the plasticizer and curing agent and continue stirring to ensure uniform distribution; finally, add the dispersant to further ensure the stability and uniformity of the coating and avoid sedimentation or stratification of the material during use;

[0023] Step 3: spraying operation;

[0024] The prepared paint then enters the spraying process. Using automatic spraying equipment, the paint is evenly sprayed onto the surface of the PCB and other electronic components that require heat dissipation. To ensure uniformity of the coating, a pneumatic spray gun should be used. The distance between the spray gun and the PCB should be kept between 15-25 cm and the spray pressure should be 2-3 bar.

[0025] During the spraying process, select the appropriate coating mode, usually a multi-layer spraying mode; after the first spraying, wait for the coating to dry for about 10 minutes before spraying a second time until the coating reaches the desired thickness; the thickness of each layer of paint should be controlled between 30μm and 50μm; after each spraying, ensure that the coating is even and free of bubbles to avoid missing or re-coating;

[0026] Step 4: UV curing;

[0027] The settings of the curing equipment should be adjusted according to the thickness and type of coating. Generally, the curing time is 10-30 seconds and the curing power is 1500W. The wavelength of the UV lamp should be selected between 250nm and 300nm. The ambient temperature during the curing process should also be controlled between 20℃ and 25℃.

[0028] Step 5: Cooling and curing effect detection;

[0029] During cooling, the coated components are placed at room temperature to cool naturally, which usually takes 10 to 15 minutes to ensure the stability of the coating. After cooling, the coating quality needs to be tested.

[0030] Step 6: Environmental adaptability test;

[0031] The test mainly includes high temperature and high humidity, low temperature and low humidity, salt spray, and ultraviolet radiation environment simulation;

[0032] High temperature and high humidity test: Place the coated component in an environment of 75°C and 90% relative humidity for 48 hours to observe changes in the coating, such as peeling, discoloration, and aging.

[0033] Low temperature and low humidity test: Expose the coating to a low temperature environment of -20°C for 24 hours to check for cracks and shedding of the coating;

[0034] Salt spray test: Expose the coating to a salt spray environment to test its corrosion resistance and ensure the coating's performance in a humid environment;

[0035] Ultraviolet radiation test: simulates the effects of long-term ultraviolet radiation on the coating to ensure the coating's UV resistance and prevent fading or performance degradation due to ultraviolet radiation;

[0036] Step 7: Quality inspection and packaging;

[0037] All coatings that pass the test will enter the quality inspection and packaging stage. The quality inspection mainly includes appearance inspection, coating thickness measurement, adhesion test, thermal conductivity test, high temperature resistance test, etc. to ensure that the quality of each batch of coatings meets the standards.

[0038] When packaging, the coated components must be carefully packaged to avoid damage during transportation or coating damage. Packaging materials should be environmentally friendly cartons, plastic bags, etc. to ensure that the product is not contaminated by the outside world. Product information, including model, production batch, and instruction manual, must be clearly marked on the product packaging box.

[0039] After packaging is completed, the product will enter the storage and transportation stage; the storage temperature should be controlled between 15℃ and 25℃, and the relative humidity should be controlled at around 50% to maintain the stability of the coating.

[0040] Its beneficial effect lies in its superior heat dissipation performance: due to the use of a mixed coating of carbon nanotubes and graphite, this product has a significantly higher thermal conductivity than traditional coatings, which can more efficiently conduct heat away from high-power electronic components, significantly improving the heat dissipation effect. Especially under high-power loads, it can effectively prevent equipment from overheating, avoiding failures or shortened equipment lifespan caused by excessive temperatures.

[0041] Enhanced Adhesion: The epoxy resin and specific additive formula used in this product significantly improves the adhesion of the coating. This means that the coating will not peel or fail under long-term high-temperature and high-load conditions, improving the stability and long-term performance of the equipment.

[0042] Significantly improved high-temperature resistance: The coating of this invention can withstand higher temperatures, which means the coating will not lose its thermal conductivity or undergo physical degradation in high-temperature environments. Compared with traditional coatings, this product has better high-temperature resistance and is suitable for electronic equipment in extreme operating environments, especially in high-temperature applications such as power equipment.

[0043] Improves long-term equipment stability: By significantly improving heat dissipation, adhesion, and high-temperature resistance, this product effectively enhances the stability of power control cabinets and other electronic equipment under long-term high-load operation. It also reduces equipment failures caused by large temperature differences and overheating, thereby extending the service life of the equipment.

[0044] Environmental protection and energy saving: This product adopts ultraviolet light curing technology, which has a faster curing speed and saves energy consumption compared with the thermal curing process of traditional coatings. At the same time, it reduces the use of traditional heat dissipation devices (such as air cooling and heat sinks), reduces the size of the equipment and noise pollution, and meets the requirements of modern energy conservation and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1This is the product experimental data obtained by the formula of the present invention. DETAILED DESCRIPTION

[0046] In order to make the technical solution more clear to those skilled in the art, Figure 1 The technical solution of the present invention is described in detail:

[0047] A carbon nanotube and graphite hybrid thermally conductive coating for power control cabinet heat dissipation includes the following raw materials: Carbon nanotubes (CNTs): used to improve the thermal conductivity of the coating. Multi-walled carbon nanotubes (MWCNTs) are selected, which have extremely strong thermal conductivity.

[0048] Graphite powder: used to enhance thermal conductivity and improve the fluidity of the coating. Graphite powder with a particle size of less than 10 μm should be used.

[0049] Epoxy resin: As a matrix material, it plays a bonding role and ensures that the thermal conductive filler is evenly distributed in the coating.

[0050] Plasticizer: adjusts the viscosity of the coating and improves coating performance.

[0051] Curing agent: ensures the curing of epoxy resin and improves the mechanical strength and temperature resistance of the coating.

[0052] Dispersant: Ensure that carbon nanotubes and graphite powder are evenly dispersed in the resin matrix to prevent agglomeration.

[0053] A carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in power control cabinets comprises, by weight: 6-8g carbon nanotubes; 34-36g graphite powder; 39-41g epoxy resin; 3-5g plasticizer; 5-7g curing agent; and 1-3g dispersant. The ratio of carbon nanotubes to graphite is usually 7:35.

[0054] Preferably, the thermal conductive coating is calculated by weight as follows: carbon nanotubes 7g; graphite powder 35g; epoxy resin 40g; plasticizer 4g; curing agent 6g; dispersant 2g. The experimental data is shown in Figure 1 ;

[0055] Experimental Data Analysis: Thermal Conductivity: The coating of this invention shows a 35.15% improvement in thermal conductivity compared to conventional coatings. The combination of carbon nanotubes and graphite significantly enhances thermal conductivity, effectively dissipating heat generated by electronic components to an external cooling system, thereby enhancing heat dissipation and ensuring stable operation of the device under high power loads.

[0056] Adhesion: The coating's adhesion is improved by 49.34%, significantly ensuring that the coating resists peeling or failure under high temperatures and prolonged use. This superior adhesion makes the coating more durable, making it particularly suitable for electronic devices subject to long-term, high-intensity use, and reduces the frequency of maintenance and coating replacement.

[0057] High-temperature resistance: The coating of this invention has a 23.88% higher high-temperature resistance than traditional coatings. This enables the product to operate stably at higher temperatures, avoiding the problem of coating degradation caused by high temperatures, making it particularly suitable for use in power equipment in extreme environments.

[0058] Average Temperature Difference: The coating significantly reduces temperature differences within equipment, reducing thermal stress caused by large temperature differences. Compared to traditional coatings, the temperature difference is reduced by 33.12%, thereby improving equipment stability and reliability.

[0059] Preferably, the plasticizer is dibutyl phthalate.

[0060] Preferably, the curing agent is tetrahydrofuran.

[0061] Preferably, the dispersant is polyvinyl alcohol.

[0062] A coating process for a carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in a power control cabinet comprises the following steps:

[0063] Step 1: Surface treatment;

[0064] Before coating, the PCBs and other important electrical components inside the power control cabinet must be surface treated to ensure they are free of oil, dust, and other impurities to ensure coating adhesion and uniformity. Common surface treatment methods include ultrasonic cleaning and chemical cleaning. Ultrasonic cleaning involves immersing the PCB in a cleaning solution, using high-frequency sound waves to remove surface oil and dirt. Chemical cleaning uses acidic or alkaline solutions to clean and activate the surface, allowing for better coating adhesion. Cleaning time and temperature must be strictly controlled at every step to avoid surface damage or degradation of material properties due to improper handling.

[0065] After cleaning, the PCB board needs to be dried, usually in an environment with a temperature of 50℃ to 60℃ for 10-15 minutes to ensure that there is no moisture left on the board surface. After the surface is clean and dry, it enters the next step of the coating process.

[0066] Step 2: Mix ingredients and stir;

[0067] First, according to a predetermined formula, carbon nanotubes, graphite powder, epoxy resin, plasticizer, curing agent, and dispersant are prepared. The ratio of each ingredient significantly impacts the coating's performance, particularly the ratio of carbon nanotubes to graphite. The typical ratio is 7:35. Epoxy resin, the primary matrix, provides strength and adhesion to the coating. The epoxy resin accounts for approximately 40% of the total coating weight, while the plasticizer accounts for approximately 4%.

[0068] When mixing, carbon nanotubes and graphite powder should be added to the epoxy resin matrix and mixed using a high shear mixer. The stirring speed and time should be adjusted according to the specific coating requirements, usually 3000 rpm and a stirring time of 10-15 minutes.

[0069] After mixing is complete, add the plasticizer and curing agent and continue stirring to ensure uniform distribution; finally, add the dispersant to further ensure the stability and uniformity of the coating and avoid sedimentation or stratification of the material during use;

[0070] Step 3: spraying operation;

[0071] The prepared paint then enters the spraying process. Using automatic spraying equipment, the paint is evenly sprayed onto the surface of the PCB and other electronic components that require heat dissipation. To ensure uniformity of the coating, a pneumatic spray gun should be used. The distance between the spray gun and the PCB should be kept between 15-25 cm and the spray pressure should be 2-3 bar.

[0072] During the spraying process, select the appropriate coating mode, usually a multi-layer spraying mode; after the first spraying, wait for the coating to dry for about 10 minutes before spraying a second time until the coating reaches the predetermined thickness; the thickness of each layer of paint should be controlled between 30μm and 50μm; after each spraying, ensure that the coating is uniform and free of bubbles to avoid missing or re-coating; at the same time, maintain a constant temperature and humidity during the spraying process, usually controlled at 25°C and 60% relative humidity, which helps to improve the adhesion and uniformity of the coating.

[0073] Step 4: UV curing;

[0074] After spraying, the coating needs to be cured by UV light to ensure its stability and durability. UV curing is a method of using ultraviolet light to cause a cross-linking reaction in the photosensitive resin in the coating, which can cure the coating in a relatively short period of time. The settings of the curing equipment should be adjusted according to the thickness and type of the coating; generally, the curing time is 10-30 seconds and the curing power is 1500W; the wavelength of the UV lamp should be selected between 250nm and 300nm; the ambient temperature during the curing process should also be controlled between 20℃ and 25℃;

[0075] Step 5: Cooling and curing effect detection;

[0076] During cooling, the coated component is placed at room temperature to cool naturally, which usually takes 10 to 15 minutes to ensure the stability of the coating. After cooling, the coating quality needs to be inspected. The main test items include: adhesion, hardness, thermal conductivity, high temperature resistance, etc. Adhesion testing is usually performed using the scratch method to ensure that the coating does not fall off in high temperature or vibration environments. Hardness testing is performed using a Mohs hardness tester to ensure that the coating surface has sufficient hardness and wear resistance. Thermal conductivity testing uses a thermal conductivity tester to ensure that the thermal conductivity of the coating meets the design requirements. High temperature resistance is tested through thermal cycling testing to ensure that the coating will not age or degrade in high temperature environments.

[0077] Step 6: Environmental adaptability test;

[0078] To ensure the long-term stability and applicability of the product in different environments, the coating of the present invention needs to pass environmental adaptability tests. The tests mainly include high temperature and high humidity, low temperature and low humidity, salt spray, and ultraviolet radiation environment simulation;

[0079] High temperature and high humidity test: Place the coated component in an environment of 75°C and 90% relative humidity for 48 hours to observe changes in the coating, such as peeling, discoloration, and aging.

[0080] Low temperature and low humidity test: Expose the coating to a low temperature environment of -20°C for 24 hours to check for cracks and shedding of the coating;

[0081] Salt spray test: Expose the coating to a salt spray environment to test its corrosion resistance and ensure the coating's performance in a humid environment;

[0082] Ultraviolet radiation test: simulates the effects of long-term ultraviolet radiation on the coating to ensure the coating's UV resistance and prevent fading or performance degradation due to ultraviolet radiation;

[0083] Step 7: Quality inspection and packaging;

[0084] All coatings that pass the test will enter the quality inspection and packaging stage. The quality inspection mainly includes appearance inspection, coating thickness measurement, adhesion test, thermal conductivity test, high temperature resistance test, etc. to ensure that the quality of each batch of coatings meets the standards.

[0085] When packaging, the coated components must be carefully packaged to avoid damage during transportation or coating damage. Packaging materials should be environmentally friendly cartons, plastic bags, etc. to ensure that the product is not contaminated by the outside world. Product information, including model, production batch, and instruction manual, must be clearly marked on the product packaging box.

[0086] After packaging is completed, the product will enter the storage and transportation stage; the storage temperature should be controlled between 15℃ and 25℃, and the relative humidity should be controlled at around 50% to maintain the stability of the coating.

[0087] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Any changes that may be made to certain parts thereof by those skilled in the art all reflect the principles of the present invention and fall within the scope of protection of the present invention.

Claims

1. A carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in power control cabinets, characterized in that: The method comprises the following raw material components: carbon nanotubes, graphite powder, epoxy resin, plasticizer, curing agent and dispersant.

2. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 1, characterized in that: Calculated by weight: 6-8g carbon nanotubes; 34-36g graphite powder; 39-41g epoxy resin; 3-5g plasticizer; 5-7g curing agent; 1-3g dispersant; wherein the ratio of carbon nanotubes to graphite is usually 7:

35.

3. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 2, characterized in that: The thermal conductive coating comprises, by weight, 7 g of carbon nanotubes, 35 g of graphite powder, 40 g of epoxy resin, 4 g of plasticizer, 6 g of curing agent, and 2 g of dispersant.

4. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 3, characterized in that: The carbon nanotubes are multi-walled carbon nanotubes.

5. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 3, characterized in that: The graphite powder is graphite powder with a particle size of less than 10 μm.

6. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 3, characterized in that: The plasticizer is dibutyl phthalate.

7. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation of a power control cabinet according to claim 3, characterized in that: The curing agent is tetrahydrofuran.

8. The carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in a power control cabinet according to claim 3, characterized in that: The dispersant is polyvinyl alcohol.

9. A coating process for a carbon nanotube and graphite mixed thermal conductive coating for heat dissipation in a power control cabinet according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Surface treatment; Before coating, the PCB boards and other important electrical components inside the power control cabinet must be surface treated to ensure that the surface is free of oil, dust, and other impurities to ensure the adhesion and uniformity of the coating. The cleaned PCB boards need to be dried, usually at a temperature of 50°C to 60°C for 10-15 minutes to ensure that there is no moisture left on the board surface. After the surface is cleaned and dried, it enters the next step of the coating process; Step 2: Mix ingredients and stir; First, according to the predetermined formula, the raw materials of carbon nanotubes, graphite powder, epoxy resin, plasticizer, curing agent and dispersant are prepared; When mixing, carbon nanotubes and graphite powder should be added to the epoxy resin matrix and mixed using a high shear mixer. The stirring speed and time should be adjusted according to the specific coating requirements, usually 3000 rpm and a stirring time of 10-15 minutes. After mixing is complete, add the plasticizer and curing agent and continue stirring to ensure uniform distribution; finally, add the dispersant to further ensure the stability and uniformity of the coating and avoid sedimentation or stratification of the material during use; Step 3: spraying operation; The prepared paint then enters the spraying process. Using automatic spraying equipment, the paint is evenly sprayed onto the surface of the PCB and other electronic components that require heat dissipation. To ensure uniformity of the coating, a pneumatic spray gun should be used. The distance between the spray gun and the PCB should be kept between 15-25 cm and the spray pressure should be 2-3 bar. During the spraying process, select the appropriate coating mode; after the first spraying, wait for the coating to dry for about 10 minutes before spraying a second time until the coating reaches the predetermined thickness; the thickness of each layer of paint should be controlled between 30μm and 50μm; after each spraying, ensure that the coating is even and free of bubbles to avoid missing or re-coating; Step 4: UV curing; Step 5: Cooling and curing effect detection; When cooling, place the coated component at room temperature to cool naturally, which usually takes 10 to 15 minutes to ensure the stability of the coating; After cooling, the coating quality needs to be tested; Step 6: Environmental adaptability test; Step 7: Quality inspection and packaging; When packaging, the coated components must be carefully packaged to avoid damage during transportation or coating damage; packaging materials should be cartons and plastic bags that meet environmental standards to ensure that the products are not contaminated by the outside world; Product information, including model, production batch, and instruction manual, must be marked on the product packaging; After packaging is completed, the product will enter the storage and transportation stage; the storage temperature should be controlled between 15℃ and 25℃, and the relative humidity should be controlled at around 50% to maintain the stability of the coating.

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