Graphene anti-corrosion heat-dissipation coating and preparation method thereof

Abstract

The invention relates to the technical field of graphene coatings, in particular to a graphene anti-corrosion heat dissipation coating and a preparation method thereof.The graphene anti-corrosion heat dissipation coating comprises a component A and a component B. The component A comprises, by weight, 50-70 parts of base resin, 10-20 parts of spherical silicon carbide, 5-20 parts of graphene slurry, 5-30 parts of anti-corrosion filler, 0-2 parts of dispersing agent, 0-2 parts of defoaming agent and 0-25 parts of diluent; comprising a component B curing chain extender. The invention has the following advantages: the curing agent composed of PPG, PCL, DETDA and MOCA is blended to generate a plurality of cross-linking reactions with matrix resin, so that the cured coating has excellent compactness, stability and mechanical properties; according to the present invention, the graphene slurry is subjected to gas phase synthesis, the graphene is uniformly dispersed, has characteristics of large sheet diameter and less layer number, and is well dispersed in the matrix resin to form the staggered and attached sheet-shaped barrier network, such that the invasion of the corrosion medium is blocked through the labyrinth effect, the coating compactness is enhanced, the corrosion resistance of the coating material is improved, the salt fog resistance of the coating material is up to 2000 h, and the resistance to 5% NaCl, 5% HSO5 and 5% NaOH is up to 90 days.

Description

Technical Field

[0001] The invention relates to the technical field of graphene coatings, in particular to a graphene anti-corrosion and heat dissipation coating and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry, the number of power equipment and communication equipment has increased dramatically. However, the economic losses caused by material corrosion in my country each year account for about 3.34% of the GDP of that year. The corrosion problem seriously affects industrial production and economic benefits. At the same time, the equipment is highly intensive, and a large number of precision devices are concentrated in small-volume equipment. Long-term high-temperature environment is easy to damage the devices and accelerate aging, which seriously affects the normal operation and service life of the equipment.

[0003] As an emerging two-dimensional material, graphene has excellent properties such as thin layer, large specific surface area, high thermal conductivity, and high strength. After being compounded with resin materials, it can significantly improve the strength and anti-corrosion thermal conductivity of the material. However, due to the π-π interaction between graphene, it is very easy to agglomerate and difficult to directly compound with resin. Even if it is dispersed in the resin, it is in a disordered state. Although it can shield and block the invasion of corrosive media, it limits the formation of thermal conductivity pathways. Traditional coatings have obvious deficiencies in anti-corrosion and heat dissipation performance and cannot meet the protection and heat dissipation needs of modern equipment. Therefore, it is of great practical significance to develop a coating with excellent anti-corrosion and heat dissipation properties. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a graphene anti-corrosion heat dissipation coating and a preparation method thereof, which effectively solves the deficiencies of the prior art.

[0005] In order to achieve the above-mentioned object, an embodiment of one aspect of the present invention provides a graphene anti-corrosion heat dissipation coating, comprising component A and component B, wherein component A comprises the following components by weight: 50-70 parts of base resin, 10-20 parts of spherical silicon carbide, 5-20 parts of graphene slurry, 5-30 parts of anti-corrosion filler, 0-2 parts of dispersant, 0-2 parts of defoaming agent and 0-25 parts of diluent; The B component is a curing chain extender containing PPG, DETDA and MOCA.

[0006] Preferably, the base resin is a polyurethane resin prepared by polycondensation of MDI-50 and PPG / PCL at 80° C., and the prepolymer -NCO / -OH molar ratio is 8:1.

[0007] Preferably, the spherical silicon carbide is prepared by the following steps: a. Carbon spheres were prepared by hydrothermal carbonization of glucose; b. Carbon spheres and silicon powder react at a molar ratio of 2:1 in argon at 1800°C; c. After oxidation decarburization at 750℃, spherical particles were obtained by classification.

[0008] Preferably, any of the above schemes is that the graphene slurry is a gas phase synthesis product, with a sheet diameter of ≥10 μm and a number of layers of ≤5.

[0009] Preferably, in any of the above schemes, the content of PPG in the B component is 70-80 parts by mass, DETDA is 15-20 parts by mass, and MOCA is 5-10 parts by mass.

[0010] Preferably, any of the above schemes is that the anti-corrosion filler is a mixture of titanium dioxide and mica powder in a ratio of 1:1.

[0011] In order to achieve the above-mentioned object, an embodiment of another aspect of the present invention provides a method for preparing a graphene anti-corrosion heat dissipation coating, comprising a base resin preparation step, a spherical silicon carbide preparation step, and a curing chain extender preparation step; The base resin preparation step comprises: S1: Weigh 200g of MDI-50 into a three-necked flask equipped with a thermometer and a condensation reflux device, place the three-necked flask in a magnetic stirring oil bath, and preheat to 50-55℃; S2: Then accurately weigh PPG (40g) and PCL (60g) which have been dried in a blast drying oven at 120℃ for 2h and cooled to 50-55℃, inject them into a three-necked flask through a syringe and mix with MDI-50, heat to 80℃ for reaction, and use the acetone-di-n-butylamine method to determine the reaction time and the -NCO content of the prepolymer. Stop the reaction when the molar ratio of -NCO / -OH in the prepolymer reaches 8; S3: After the reaction is completed, the device is dismantled, and the prepolymer is taken out and sealed for standby use; The spherical silicon carbide preparation steps include: S1: Glucose was used as the organic carbon source, and a glucose aqueous solution was prepared at a concentration of 1 mol / L, and aluminum hexametaphosphate was added at 3% of the mass of the organic carbon source, and the mixture was stirred to obtain a mixed solution; S2: placing the mixed solution into a reactor, performing a hydrothermal reaction at a heating rate of 10°C / min, and finally achieving a reaction temperature of 230°C. After 4 hours of reaction, carbon spheres were obtained, and the obtained carbon spheres were washed with ethanol and dried. S3: Mix the carbon spheres and silicon powder in a molar ratio of 2:1, and in a high-purity argon environment, initially heat to 900°C at 10°C / min, keep warm for 2 hours, then heat to 1800°C at 3°C / min, keep warm for 2 hours, and finally cool to room temperature at 4°C / min to obtain a reaction product; S4: The reaction product is oxidized at 750°C for 4 hours for decarburization treatment. The decarburized powder is dispersed in water at a concentration of 15 g / L. After settling for 5 minutes, the upper layer of liquid is collected and dried to obtain spherical silicon carbide material with uniform particle size distribution. The curing chain extender preparation step comprises: S1: Weigh 200g PPG and put it into a forced air drying oven at 120℃ for 2h, then weigh 74g dry PPG and mix it with 18.8g MOCA and add 0.7g DETDA and mix well; S2: Then place it in a forced air drying oven at 110°C for 45 minutes to dry MOCA and dissolve it in PPG. After taking it out, stir it with a glass rod to mix it evenly, which is used as component B.

[0012] The present invention has the following advantages: 1. The graphene anti-corrosion heat dissipation coating and its preparation method, by mixing the curing agent composed of PPG, PCL, DETDA and MOCA, produces multiple cross-linking reactions with the matrix resin, so that the cured coating has excellent density, stability and mechanical properties. At the same time, the gas-phase synthesized graphene slurry is used, and its graphene is evenly dispersed, large in diameter, and few in number. It can be well dispersed in the matrix resin to form a staggered and attached sheet barrier network, which uses the maze effect to block the invasion of corrosive media, enhance the density of the coating, and improve the anti-corrosion performance of the coating. The coating has a salt spray resistance of up to 2000h, and a resistance to 5% NaCl, 5% H2SO4, and 5% NaOH of up to 90 days.

[0013] 2. The graphene anti-corrosion heat dissipation coating uses spherical silicon carbide with excellent thermal conductivity, corrosion resistance and wear resistance as gap filling material to fill the gaps between graphene sheets, so that the disordered graphene sheets are linked by spherical silicon carbide to form a heat conduction path, which can effectively conduct the heat from the base surface out through the path. The temperature reduction on the heat sink can reach up to 9°C, which has a good heat dissipation effect.

[0014] 3. The graphene anti-corrosion and heat dissipation coating has excellent corrosion resistance and heat dissipation effects. It can not only meet the use requirements of various fields such as power equipment and communication equipment, but also has a long service life. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0016] A graphene anti-corrosion heat dissipation coating, which is a two-component system, including component A and component B, wherein component A includes the following components by weight: 50-70 parts of base resin, 10-20 parts of spherical silicon carbide, 5-20 parts of graphene slurry, 5-30 parts of anti-corrosion filler, 0-2 parts of dispersant, 0-2 parts of defoamer and 0-25 parts of diluent; The B component is a curing chain extender containing PPG, DETDA and MOCA.

[0017] As an optional technical solution of the present invention, the base resin is a polyurethane resin, which is formed by condensation of MDI-50 and PPG / PCL at 80° C., and the prepolymer -NCO / -OH molar ratio is 8:1.

[0018] As an optional technical solution of the present invention, the spherical silicon carbide is prepared by the following steps: a. Carbon spheres were prepared by hydrothermal carbonization of glucose; b. Carbon spheres and silicon powder react at a molar ratio of 2:1 in argon at 1800°C; c. After oxidation decarburization at 750℃, spherical particles were obtained by classification.

[0019] As an optional technical solution of the present invention, the graphene slurry is a gas phase synthesis product, with a sheet diameter of ≥10 μm and a layer number of ≤5 layers.

[0020] As an optional technical solution of the present invention, the content of PPG in the B component is 70-80 parts by mass, DETDA is 15-20 parts by mass, and MOCA is 5-10 parts by mass.

[0021] As an optional technical solution of the present invention, the anti-corrosion filler is a 1:1 compound of titanium dioxide and mica powder.

[0022] A method for preparing a graphene anti-corrosion heat dissipation coating, comprising a base resin preparation step, a spherical silicon carbide preparation step, and a curing chain extender preparation step; The base resin preparation step comprises: S1: Weigh 200g of MDI-50 into a three-necked flask equipped with a thermometer and a condensation reflux device, place the three-necked flask in a magnetic stirring oil bath, and preheat to 50-55℃; S2: Then accurately weigh PPG (40g) and PCL (60g) which have been dried in a blast drying oven at 120℃ for 2h and cooled to 50-55℃, inject them into a three-necked flask through a syringe and mix with MDI-50, heat to 80℃ for reaction, and use the acetone-di-n-butylamine method to determine the reaction time and the -NCO content of the prepolymer. Stop the reaction when the molar ratio of -NCO / -OH in the prepolymer reaches 8; S3: After the reaction is completed, the device is dismantled, and the prepolymer is taken out and sealed for standby use; The spherical silicon carbide preparation steps include: S1: Glucose was used as the organic carbon source, and a glucose aqueous solution was prepared at a concentration of 1 mol / L, and aluminum hexametaphosphate was added at 3% of the mass of the organic carbon source, and the mixture was stirred to obtain a mixed solution; S2: placing the mixed solution into a reactor, performing a hydrothermal reaction at a heating rate of 10°C / min, and finally achieving a reaction temperature of 230°C. After 4 hours of reaction, carbon spheres were obtained, and the obtained carbon spheres were washed with ethanol and dried. S3: Mix the carbon spheres and silicon powder in a molar ratio of 2:1, and in a high-purity argon environment, initially heat to 900°C at 10°C / min, keep warm for 2 hours, then heat to 1800°C at 3°C / min, keep warm for 2 hours, and finally cool to room temperature at 4°C / min to obtain a reaction product; S4: The reaction product is oxidized at 750°C for 4 hours for decarburization treatment. The decarburized powder is dispersed in water at a concentration of 15 g / L. After settling for 5 minutes, the upper layer of liquid is collected and dried to obtain spherical silicon carbide material with uniform particle size distribution. The curing chain extender preparation step comprises: S1: Weigh 200g PPG and put it into a forced air drying oven at 120℃ for 2h, then weigh 74g dry PPG and mix it with 18.8g MOCA and add 0.7g DETDA and mix well; S2: Then place it in a forced air drying oven at 110°C for 45 minutes to dry MOCA and dissolve it in PPG. After taking it out, stir it with a glass rod to mix it evenly, which is used as component B. Example

[0023] Step 1: Take the following raw materials by weight percentage: stir 110g base resin, 1g BYK-163 dispersant, 1g BYK-054, and 38g diluent at a speed of 500r / min for 15min until uniform, then gradually add 12g titanium dioxide, 10g graphene slurry, and 28g spherical silicon carbide at a speed of 800r / min and stir for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating. Example

[0024] Step 1: Take the following raw materials by weight percentage: 110g base resin, 1g BYK-163 dispersant, 1g BYK-054 at a speed of 500r / min, 28g diluent, stir for 15min until uniform, then gradually add 12g titanium dioxide, 20g graphene slurry, 28g spherical silicon carbide at a speed of 800r / min and stir for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating. Example

[0025] Step 1: Take the following raw materials by weight percentage: stir 110g base resin, 1g BYK-163 dispersant, 1g BYK-054, and 18g diluent at 500r / min for 15min until uniform, then gradually add 12g titanium dioxide, 30g graphene slurry, and 28g spherical silicon carbide at 800r / min for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating. Example

[0026] Step 1: Take the following raw materials by weight percentage: stir 110g base resin, 1g BYK-163 dispersant, 1g BYK-054, and 8g diluent at 500r / min for 15min until uniform, then gradually add 12g titanium dioxide, 40g graphene slurry, and 28g spherical silicon carbide at 800r / min for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating.

[0027] Comparative Example 1: Step 1: Take the following raw materials by weight percentage: stir 110g base resin, 1g BYK-163 dispersant, 1g BYK-054, and 48g diluent at 500r / min for 15min until uniform, then gradually add 12g titanium dioxide and 28g spherical silicon carbide at 800r / min for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating.

[0028] Comparative Example 2: Step 1: Take the following raw materials by weight percentage: stir 110g base resin, 1g BYK-163 dispersant, 1g BYK-054, and 46g diluent at a speed of 500r / min for 15min until uniform, then gradually add 12g titanium dioxide and 30g graphene slurry at a speed of 800r / min and stir for 45min to obtain premix A component; Step 2: Weigh 100 g of the prepared component A and mix with 4.6 g of component B, stir and ripen for 15 minutes to obtain the graphene anti-corrosion heat dissipation coating.

[0029] Performance Testing The coatings prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were applied to tinplates of composite specifications to prepare test specimens that met the specifications. The samples were tested for salt spray resistance in accordance with the reference standard GB / T1771-2007. The materials were applied to heat sinks and the surface temperature was measured under a 78°C heating environment. The temperature was compared with that of bare heat sinks without coating, and the temperature reduction was calculated to characterize the heat dissipation effect. The test results are as follows: From the test results, it can be seen that Examples 1-3 all have good anti-corrosion and heat dissipation properties. Based on the large specific surface area, high strength and high thermal conductivity of graphene and the bridging of spherical silicon carbide in the base resin to form a maze effect and a thermal conductive path, the integrated anti-corrosion and heat dissipation functions are achieved. In Implementation 4, after adding too much graphene slurry, filler agglomeration and poor dispersion occurred, which made it difficult to apply the coating to form a uniform film. Therefore, it can be determined that graphene as a filler also has an addition threshold, and exceeding this value will greatly affect the material performance. Comparison of Comparative Examples 1-2 shows that graphene as a thermally conductive filler can improve the heat dissipation performance of the material, but the effect is not ideal. After spherical silicon carbide is used as a bridge, the formation of a thermal conductive path greatly improves the heat dissipation performance of the material.

[0030] In summary, by mixing the curing agent composed of PPG, PCL, DETDA and MOCA, a variety of cross-linking reactions are produced with the matrix resin, so that the cured coating has excellent density, stability and mechanical properties. At the same time, the use of gas-phase synthetic graphene slurry, the graphene is evenly dispersed, the flake diameter is large, and the number of layers is small. It can be well dispersed in the matrix resin to form a staggered and attached sheet barrier network, which uses the maze effect to block the invasion of corrosive media, enhance the density of the coating, and improve the anti-corrosion performance of the coating. The coating has a salt spray resistance of up to 2000h, and is resistant to 5% NaCl, 5% H2SO4, and 5% NaOH for 90 days. By using spherical silicon carbide with excellent thermal conductivity, excellent corrosion resistance and wear resistance as a gap filling material, the gaps between graphene sheets are filled, and the disordered graphene sheets are linked through spherical silicon carbide to form a heat conduction path, which can effectively conduct the heat of the base surface out through the path. The maximum temperature reduction on the heat sink can reach 9°C, which has a good heat dissipation effect and excellent corrosion resistance and heat dissipation effect. It can not only meet the use requirements of various fields such as power equipment and communication equipment, but also has a long service life.

[0031] 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 graphene anti-corrosion heat dissipation coating, characterized in that: It is a two-component system, including component A and component B, wherein component A includes the following components by weight: 50-70 parts of base resin, 10-20 parts of spherical silicon carbide, 5-20 parts of graphene slurry, 5-30 parts of anticorrosive filler, 0-2 parts of dispersant, 0-2 parts of defoamer and 0-25 parts of diluent; The B component is a curing chain extender containing PPG, DETDA and MOCA.

2. The graphene anti-corrosion heat dissipation coating according to claim 1, characterized in that: The base resin is a polyurethane resin, which is prepared by polycondensation of MDI-50 and PPG / PCL at 80° C., and the prepolymer -NCO / -OH molar ratio is 8:

1.

3. The graphene anti-corrosion heat dissipation coating according to claim 2, characterized in that: The spherical silicon carbide is prepared by the following steps: a. Carbon spheres were prepared by hydrothermal carbonization of glucose; b. Carbon spheres and silicon powder react at a molar ratio of 2:1 in argon at 1800°C; c. After oxidation decarburization at 750℃, spherical particles were obtained by classification.

4. The graphene anti-corrosion heat dissipation coating according to claim 3, characterized in that: The graphene slurry is a gas phase synthesis product, with a sheet diameter of ≥10 μm and a layer number of ≤5 layers.

5. The graphene anti-corrosion heat dissipation coating according to claim 4, characterized in that: The content of PPG in the B component is 70-80 parts by mass, DETDA is 15-20 parts by mass, and MOCA is 5-10 parts by mass.

6. The graphene anti-corrosion heat dissipation coating according to claim 5, characterized in that: The anti-corrosion filler is a mixture of titanium dioxide and mica powder in a ratio of 1:

1.

7. A method for preparing a graphene anti-corrosion heat dissipation coating, used for preparing the graphene anti-corrosion heat dissipation coating according to any one of claims 1 to 6, characterized in that: The method comprises the steps of preparing a base resin, preparing a spherical silicon carbide and preparing a curing chain extender; The base resin preparation step comprises: S1: Weigh 200g of MDI-50 into a three-necked flask equipped with a thermometer and a condensation reflux device, place the three-necked flask in a magnetic stirring oil bath, and preheat to 50-55℃; S2: Then accurately weigh PPG (40g) and PCL (60g) which have been dried in a blast drying oven at 120℃ for 2h and cooled to 50-55℃, inject them into a three-necked flask through a syringe and mix with MDI-50, heat to 80℃ for reaction, and use the acetone-di-n-butylamine method to determine the reaction time and the -NCO content of the prepolymer. Stop the reaction when the molar ratio of -NCO / -OH in the prepolymer reaches 8; S3: After the reaction is completed, the device is dismantled, and the prepolymer is taken out and sealed for standby use; The spherical silicon carbide preparation steps include: S1: Glucose was used as the organic carbon source, and a glucose aqueous solution was prepared at a concentration of 1 mol / L, and aluminum hexametaphosphate was added at 3% of the mass of the organic carbon source, and the mixture was stirred to obtain a mixed solution; S2: placing the mixed solution into a reactor, performing a hydrothermal reaction at a heating rate of 10°C / min, and finally achieving a reaction temperature of 230°C. After 4 hours of reaction, carbon spheres were obtained, and the obtained carbon spheres were washed with ethanol and dried. S3: Mix the carbon spheres and silicon powder in a molar ratio of 2:1, and in a high-purity argon environment, initially heat to 900°C at 10°C / min, keep warm for 2 hours, then heat to 1800°C at 3°C / min, keep warm for 2 hours, and finally cool to room temperature at 4°C / min to obtain a reaction product; S4: The reaction product is oxidized at 750°C for 4 hours for decarburization. The decarburized powder is dispersed in water at a concentration of 15 g / L. The upper layer of liquid is collected after settling for 5 minutes and dried to obtain spherical silicon carbide material with uniform particle size distribution. The curing chain extender preparation step comprises: S1: Weigh 200g PPG and put it into a forced air drying oven at 120℃ for 2h, then weigh 74g dry PPG and mix it with 18.8g MOCA and add 0.7g DETDA and mix well; S2: Then place it in a forced air drying oven at 110°C for 45 minutes to dry MOCA and dissolve it in PPG. After taking it out, stir it with a glass rod to mix it evenly, which is used as component B.