Coating material for heat dissipation aluminum pipe and preparation process of coating material

Abstract

The invention relates to the technical field of paint coatings, in particular to a coating material for a heat dissipation aluminum pipe and a preparation process thereof.The coating material for the heat dissipation aluminum pipe achieves unification of heat conduction, heat radiation, corrosion prevention and surface self-maintenance performance through reasonable design and synergistic integration of organic silicon modified acrylic resin and multiple functional components; wherein the modified composite inorganic nano filler is composed of a boron nitride nanosheet with high thermal conductivity and electrical insulation, nano aluminum oxide and a small amount of graphene oxide, a continuous and stable three-dimensional heat conduction path is formed in a resin matrix, and the conduction efficiency of heat in the thickness direction of the coating is effectively improved; meanwhile, the coating modified silicon carbide micro powder and the rare earth doped oxide have excellent heat radiation capacity in the infrared band, heat on the surface of the aluminum pipe can be efficiently radiated into the environment in the form of electromagnetic waves, and therefore the overall heat dissipation effect is remarkably enhanced under the condition that convection is limited, the two mechanisms of heat conduction and radiation supplement each other, and the heat dissipation efficiency is improved. And the performance bottleneck of a single heat dissipation path is broken through.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint coating, in particular to a coating material for heat dissipation aluminum pipe and a preparation process thereof. BACKGROUND

[0002] With the development of refrigeration equipment such as air conditioners and heat exchangers towards high efficiency and energy saving, heat dissipation aluminum heat exchange pipes are widely used due to their light weight and good thermal conductivity. However, aluminum pipes face problems such as limited heat dissipation efficiency, surface corrosion and dust accumulation during long-term operation, especially under natural convection or low wind speed conditions. Simply relying on the thermal conductivity of the metal body cannot meet the rapid heat dissipation demand. Traditional coatings focus on a single function, such as corrosion prevention or insulation, lack of systematic design of heat conduction and thermal radiation synergy mechanism, and poor compatibility between fillers and resin matrix, which can easily lead to uneven dispersion, high interfacial thermal resistance, insufficient coating adhesion, and difficulty in achieving long-term stable heat dissipation performance.

[0003] In addition, existing heat dissipation coatings often ignore environmental adaptability and service life. Ordinary organic coatings have limited weather resistance and are prone to aging and failure in hot and humid or salt-containing environments. While the addition of corrosion inhibitors often cannot provide long-term protection due to premature release or incompatibility with the resin system. At the same time, dust and oil accumulation on the surface of the coating will significantly reduce the heat exchange efficiency, but composite coatings with self-cleaning and high-efficiency heat dissipation functions are still relatively scarce. Therefore, it is urgent to develop a multifunctional coating material that integrates high thermal conductivity, strong infrared radiation, intelligent corrosion prevention and surface self-maintenance, and through reasonable component design and interface regulation, to achieve the synergistic improvement of aluminum pipe heat dissipation performance and durability. SUMMARY

[0004] Technical problems to be solved In view of the above-mentioned shortcomings of the prior art, the present application provides a coating material for heat dissipation aluminum pipe and a preparation process thereof, which can effectively solve the problem of single function of the existing heat dissipation coating, and cannot simultaneously have high heat dissipation and corrosion resistance.

[0005] Technical scheme

[0006] To achieve the above purpose, the present application is realized by the following technical scheme: A coating material for heat dissipation aluminum pipe, the composition of the coating material for heat dissipation aluminum pipe comprises: silicone modified acrylic resin, modified composite inorganic nano filler, coated modified silicon carbide powder, modified rare earth oxide and corrosion inhibition microcapsule; The silicone modified acrylic resin is prepared by reaction of methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate and silane coupling agent KH-570 as main raw materials; The modified composite inorganic nano filler is prepared by modifying the composite inorganic nano filler with silane coupling agent KH-550; The coated modified silicon carbide powder is prepared by modifying silicon carbide powder as raw material; The modified rare earth oxide is prepared by modifying yttrium oxide, lanthanum oxide and cerium dioxide as raw material; The corrosion inhibition microcapsule is prepared by coating molybdate / phosphate corrosion inhibitor components with urea-formaldehyde prepolymer solution.

[0007] Further, the preparation steps of the organic silicon modified acrylic resin are as follows: Step A, 35-45 parts by weight of methyl methacrylate, 30-40 parts by weight of butyl acrylate, 5-10 parts by weight of hydroxyethyl methacrylate, 2-3 parts by weight of hexafluorobutyl methacrylate, 3-5 parts by weight of acrylic acid, 5-6 parts by weight of silane coupling agent KH-570 and 0.8-1.2 parts by weight of azobisisobutyronitrile are mixed, stirred at a stirring speed of 300-400 r / min for 15 min, and the obtained product is marked as monomer component; Step B, 40-60 parts by weight of dimethylbenzene is poured into a flask, deoxygenated by nitrogen, stirred at a stirring speed of 300-500 r / min, heated to 85℃, and the above-mentioned monomer component is added dropwise within 3 h, 0.3-0.5 parts by weight of azobisisobutyronitrile is added after 2 h of incubation, and the obtained product is the organic silicon modified acrylic resin after 1 h of continuous incubation.

[0008] Further, the composite inorganic nano filler is prepared by mixing boron nitride nanosheet, nano alumina powder and graphene oxide at a weight ratio of 6:3:1.

[0009] Further, the preparation method of the modified composite inorganic nano filler is as follows: 3-5 parts by weight of silane coupling agent KH-550 is dispersed in 400-500 parts by weight of 80% mass fraction ethanol aqueous solution, hydrolyzed by stirring, 100 parts by weight of composite inorganic nano filler is added, and ultrasonic dispersion is carried out at a power of 300 W for 30 min, then it is placed in a reflux reactor at a temperature of 80-90℃ for 2-4 h, filtered, washed with anhydrous ethanol for 3-5 times, and vacuum dried at a temperature of 60℃ until constant weight, and the obtained product is the modified composite inorganic nano filler.

[0010] Further, the preparation steps of the coated modified silicon carbide powder are as follows: Step 1, 45-50 parts by weight of silicon carbide powder is placed in a flask, 150 parts by weight of 5% mass fraction hydrochloric acid solution is added, stirred and refluxed at a temperature of 85℃ for 24 h, filtered, dried at a temperature of 105℃ until constant weight, ground through a 325 mesh sieve, and the obtained product is marked as purified silicon carbide powder; Step 2, 45-50 parts by weight of purified silicon carbide powder is placed in a flask, 50 parts by weight of anhydrous ethanol and 1 part by weight of polyethylene glycol are added, and then ultrasonic dispersion is carried out at a power of 300 W for 30 min. Stirring reflux is carried out at a temperature of 80℃ for 5 h. After filtration, it is washed with deionized water for 3-5 times, and then dried at a temperature of 70℃ until the weight is constant. After grinding through a 325 mesh sieve, the obtained is coated modified silicon carbide powder.

[0011] Further, the preparation steps of the modified rare earth oxide are: Step I, yttrium oxide, lanthanum oxide and cerium dioxide are mixed according to a weight ratio of 17:3:1. Then, 100 parts by weight of the mixture is dispersed in 400-500 parts by weight of anhydrous ethanol, and the obtained is denoted as a dispersion component; Step II, 2-4 parts by weight of silane coupling agent KH-550 is added to the dispersion component. Ultrasonic dispersion is carried out at a power of 300 W for 1 h, and then reflux reaction is carried out at a temperature of 85℃ for 2-3 h. After suction filtration, it is washed with anhydrous ethanol for 3-5 times, and then vacuum dried at a temperature of 60℃ until the weight is constant. The obtained is the modified rare earth oxide.

[0012] Further, the preparation steps of the corrosion inhibition microcapsule are: Step A, 5-6 parts by weight of urea is added to 10-12 parts by weight of formaldehyde solution with a mass fraction of 37%. After stirring and dissolving, triethanolamine is added dropwise to adjust the pH value to 9. After heating to 70℃ and maintaining for 1 h, the obtained is denoted as a urea-formaldehyde prepolymer solution; Step B, 13-14 parts by weight of sodium molybdate and 6-7 parts by weight of zinc phosphate are poured into 30-35 parts by weight of deionized water. After stirring at a stirring speed of 400-500 r / min for 30 min, the obtained is denoted as a molybdate / phosphate corrosion inhibitor component; Step C, 100 parts by weight of cyclohexane and 1-2 parts by weight of emulsifier OP-10 are poured into a flask. After stirring at a stirring speed of 400-500 r / min for 30 min, it is poured into the above-mentioned molybdate / phosphate corrosion inhibitor component. After high-speed shearing emulsification at a stirring speed of 8000-10000 r / min for 5 min, the obtained is denoted as a water-in-oil microemulsion; Step D, the water-in-oil microemulsion is heated to 55-60℃, and then 10 parts by weight of the urea-formaldehyde prepolymer solution is added. After adjusting the pH value to 4.0-4.5 with 10% hydrochloric acid solution, it is maintained for 3-4 h. Then, it is cooled to room temperature and the microcapsule is collected by filtration. After washing with cyclohexane, anhydrous ethanol and deionized water for 3 times, respectively, it is vacuum dried at a temperature of 40-50℃ for 12 h. The obtained is the corrosion inhibition microcapsule.

[0013] A preparation process of a coating material for a heat dissipation aluminum pipe, the preparation process is: S1, 10-15 parts by weight of xylene and 5-8 parts by weight of butyl acetate are added to 40-50 parts by weight of silicone-modified acrylic resin, and after stirring and mixing, 15-20 parts by weight of modified composite inorganic nano filler, 5-8 parts by weight of coated modified silicon carbide powder, and 3-6 parts by weight of modified rare earth oxide are added, and after mixing and dispersing, the obtained is denoted as the base component; S2, the base component is ground through a three-roll grinder for 2-3 passes and then passed through an 800-mesh sieve, followed by adding 1-3 parts by weight of corrosion-inhibiting microcapsules, 0.5-0.9 parts by weight of a leveling agent, 0.3-0.6 parts by weight of a defoaming agent, and 0.5-0.9 parts by weight of silane coupling agent KH-560, stirring uniformly, adjusting the viscosity to 30-60 mPa·s with xylene, and continuing to stir and passing through a 100-mesh sieve to obtain the coating material for the heat dissipation aluminum pipe.

[0014] Further, the stirring and mixing method in S1 is stirring at a stirring speed of 300-400 r / min for 15 min, and the mixing and dispersing method in S1 is first stirring at a stirring speed of 800-1000 r / min for 30 min, and then high-speed dispersing at a stirring speed of 2000-3000 r / min for 60 min.

[0015] Further, the stirring and mixing method in S1 is stirring at a stirring speed of 300-400 r / min for 15 min, and the mixing and dispersing method in S1 is first stirring at a stirring speed of 800-1000 r / min for 30 min, and then high-speed dispersing at a stirring speed of 2000-3000 r / min for 60 min.

[0016] Beneficial effects

[0017] The present application provides a coating material for heat dissipation aluminum pipe and a preparation process thereof, compared with the prior art, the present application has the following beneficial effects: The coating material for heat dissipation aluminum pipe in the present application realizes the unity of heat conduction, heat radiation, corrosion resistance and surface self-maintenance performance through the reasonable design and synergistic integration of silicone-modified acrylic resin and various functional components; wherein the modified composite inorganic nano filler is composed of boron nitride nanosheet, nano alumina and a small amount of graphene oxide which are high thermal conductivity and electrically insulated, forming a continuous and stable three-dimensional heat conduction path in the resin matrix, effectively improving the conduction efficiency of heat along the thickness direction of the coating; at the same time, the coated modified silicon carbide powder and rare earth doped oxide have excellent heat radiation ability in the infrared band, which can efficiently radiate the heat on the surface of the aluminum pipe to the environment in the form of electromagnetic waves, thereby significantly enhancing the overall heat dissipation effect under the condition of limited convection, and the two mechanisms of heat conduction and radiation complement each other, breaking through the performance bottleneck of single heat dissipation path.

[0018] In terms of corrosion prevention, corrosion-inhibiting microcapsules are introduced into the system as additives. Their shells are made of urea-formaldehyde resin, and the interiors are loaded with a composite corrosion inhibitor of molybdate and phosphate. When the coating has local defects due to mechanical damage or environmental erosion, the microcapsules can release corrosion-inhibiting ions as needed, forming a dense passivation film in situ on the aluminum substrate surface, effectively blocking the electrochemical corrosion reaction. This "release-on-demand" mechanism not only prolongs the protection time, but also avoids the problem of premature loss of traditional corrosion inhibitors or adverse interactions with the resin system, thereby achieving long-term and precise corrosion inhibition.

[0019] Furthermore, each inorganic functional filler is modified by silane coupling agent or polymer coating, which significantly improves its interfacial compatibility and dispersion stability with the organosilicon-modified acrylic resin matrix. The resin itself is incorporating fluorinated monomers and carboxyl / hydroxyl functional groups, which not only endow the coating with low surface energy to achieve hydrophobic and antifouling effects, but also enhance its adhesion to the aluminum tube substrate. Through multi-level synergy of molecular design, filler modification and process control, the entire system enables the coating to maintain good workability and film formation while possessing multiple functions such as efficient heat dissipation, durable corrosion protection and surface self-cleaning, providing a comprehensive and high-performance surface protection solution for the reliable operation of aluminum heat exchange components under complex working conditions. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The present invention will be further described below with reference to embodiments.

[0022] Example 1

[0023] This embodiment provides a coating material for heat dissipation aluminum pipes. The coating material for heat dissipation aluminum pipes comprises: organosilicon-modified acrylic resin, modified composite inorganic nanofiller, coated modified silicon carbide micropowder, modified rare earth oxide, and corrosion-inhibiting microcapsules. The organosilicon-modified acrylic resin is prepared by reacting methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate and silane coupling agent KH-570 as the main raw materials. The preparation steps of the organosilicon-modified acrylic resin are as follows: Step A: Weigh 35 parts by weight of methyl methacrylate, 30 parts by weight of butyl acrylate, 5 parts by weight of hydroxyethyl methacrylate, 2 parts by weight of hexafluorobutyl methacrylate, 3 parts by weight of acrylic acid, 5 parts by weight of silane coupling agent KH-570 and 0.8 parts by weight of azobisisobutyronitrile and mix them. Stir at 300 r / min for 15 min. The result is recorded as the monomer component. Step B: Pour 40 parts by weight of xylene into a flask, purge with nitrogen to remove oxygen, stir and heat to 85°C at a stirring speed of 300 r / min, add the above monomer components dropwise over 3 hours, keep warm for 2 hours, then add 0.3 parts by weight of azobisisobutyronitrile, and continue to keep warm for 1 hour. The resulting product is silicone-modified acrylic resin.

[0024] The modified composite inorganic nanofiller was prepared by modifying the composite inorganic nanofiller with silane coupling agent KH-550; The composite inorganic nanofiller is prepared by mixing boron nitride nanosheets, nano-alumina powder and graphene oxide in a weight ratio of 6:3:1.

[0025] The preparation method of the modified composite inorganic nanofiller is as follows: Weigh 3 parts by weight of silane coupling agent KH-550 and disperse it in 400 parts by weight of 80% ethanol aqueous solution. After stirring and hydrolyzing, add 100 parts by weight of composite inorganic nanofiller and ultrasonically disperse it at 300W for 30min. Then, reflux it at 80℃ for 2h. After filtration, wash it 3 times with anhydrous ethanol and vacuum dry it at 60℃ to constant weight. The result is the modified composite inorganic nanofiller.

[0026] The coated modified silicon carbide micro powder is prepared by modifying silicon carbide micro powder as raw material; The preparation steps of the coated modified silicon carbide micro powder are as follows: Step 1: Weigh 45 parts by weight of silicon carbide micro powder and place it in a flask. Add 150 parts by weight of 5% hydrochloric acid solution and stir and reflux at 85°C for 24 hours. After filtration, dry at 105°C to constant weight. Grind through a 325-mesh sieve. The resulting product is called purified silicon carbide micro powder. Step 2: Weigh 45 parts by weight of purified silicon carbide micro powder and place it in a flask. Add 50 parts by weight of anhydrous ethanol and 1 part by weight of polyethylene glycol. Then, ultrasonically disperse the powder at 300W for 30 minutes. Stir and reflux at 80℃ for 5 hours. After filtration, rinse the powder three times with deionized water. Dry the powder at 70℃ until constant weight. Grind the powder through a 325-mesh sieve to obtain the coated modified silicon carbide micro powder.

[0027] Modified rare earth oxides are prepared by modifying yttrium oxide, lanthanum oxide and cerium dioxide as raw materials; The preparation steps of the modified rare earth oxides are as follows: Step I: Weigh yttrium oxide, lanthanum oxide and cerium dioxide in a weight ratio of 17:3:1 and mix them. Then weigh 100 parts by weight of the mixture and disperse it in 400 parts by weight of anhydrous ethanol. The result is recorded as the dispersed component. Step II: Add 2 parts by weight of silane coupling agent KH-550 to the dispersion component, ultrasonically disperse at 300W for 1 hour, reflux at 85℃ for 2 hours, filter, wash 3 times with anhydrous ethanol, and vacuum dry at 60℃ to constant weight. The result is the modified rare earth oxide.

[0028] Corrosion-inhibiting microcapsules were prepared by coating molybdate / phosphate corrosion inhibitor components with a urea-formaldehyde prepolymer solution. The preparation steps of the corrosion-inhibiting microcapsules are as follows: Step A: Add 5 parts by weight of urea to 10 parts by weight of formaldehyde solution with a mass fraction of 37%, stir to dissolve, add triethanolamine dropwise to adjust the pH value to 9, heat to 70°C and keep the reaction at this temperature for 1 hour. The resulting solution is called urea-formaldehyde prepolymer solution. Step B: Weigh 13 parts by weight of sodium molybdate and 6 parts by weight of zinc phosphate and pour them into 30 parts by weight of deionized water. Stir at 400 r / min for 30 min. The resulting product is recorded as the molybdate / phosphate corrosion inhibitor component. Step C: Pour 100 parts by weight of cyclohexane and 1 part by weight of emulsifier OP-10 into a flask, stir at 400 r / min for 30 min, then pour in the above molybdate / phosphate corrosion inhibitor component, and emulsify at 8000 r / min for 5 min. The resulting product is called water-in-oil microemulsion. Step D: After heating the water-in-oil microemulsion to 55°C, add 10 parts by weight of urea-formaldehyde prepolymer solution. Adjust the pH value to 4.0 with 10% hydrochloric acid solution and keep the reaction at this temperature for 3 hours. Then cool to room temperature and filter to collect the microcapsules. Wash them three times in sequence with cyclohexane, anhydrous ethanol and deionized water, and then vacuum dry them at 40°C for 12 hours. The resulting microcapsules are corrosion-inhibiting microcapsules.

[0029] A preparation process for a coating material for heat dissipation aluminum pipes, the preparation process is as follows: S1. Add 10 parts by weight of xylene and 5 parts by weight of butyl acetate to 40 parts by weight of silicone-modified acrylic resin. Stir at 300 r / min for 15 min, then add 15 parts by weight of modified composite inorganic nanofiller, 5 parts by weight of coated modified silicon carbide micro powder, and 3 parts by weight of modified rare earth oxide. Stir at 800 r / min for 30 min, then disperse at 2000 r / min for 60 min. The resulting product is recorded as the base material component. S2. After grinding the base material components twice with a three-roll mill, pass them through an 800-mesh sieve. Then add 1 part by weight of corrosion-inhibiting microcapsules, 0.5 parts by weight of leveling agent, 0.3 parts by weight of defoamer, and 0.5 parts by weight of silane coupling agent KH-560. Stir at a stirring speed of 400 r / min for 30 min, then add xylene to adjust the viscosity to 30 mPa·s. Stir at the original stirring speed for 10 min and pass through a 100-mesh sieve. The resulting coating material for heat dissipation aluminum pipes is the coating material.

[0030] Example 2

[0031] This embodiment provides a coating material for heat dissipation aluminum pipes. The coating material for heat dissipation aluminum pipes comprises: organosilicon-modified acrylic resin, modified composite inorganic nanofiller, coated modified silicon carbide micropowder, modified rare earth oxide, and corrosion-inhibiting microcapsules. The organosilicon-modified acrylic resin is prepared by reacting methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate and silane coupling agent KH-570 as the main raw materials. The preparation steps of the organosilicon-modified acrylic resin are as follows: Step A: Weigh 45 parts by weight of methyl methacrylate, 40 parts by weight of butyl acrylate, 10 parts by weight of hydroxyethyl methacrylate, 3 parts by weight of hexafluorobutyl methacrylate, 5 parts by weight of acrylic acid, 6 parts by weight of silane coupling agent KH-570 and 1.2 parts by weight of azobisisobutyronitrile and mix them. Stir at a stirring speed of 400 r / min for 15 min. The result is recorded as the monomer component. Step B: Pour 60 parts by weight of xylene into a flask, purge with nitrogen to remove oxygen, stir and heat to 85°C at a stirring speed of 500 r / min, add the above monomer components dropwise over 3 hours, keep warm for 2 hours, then add 0.5 parts by weight of azobisisobutyronitrile, and continue to keep warm for 1 hour. The resulting product is silicone-modified acrylic resin.

[0032] The modified composite inorganic nanofiller was prepared by modifying the composite inorganic nanofiller with silane coupling agent KH-550; The composite inorganic nanofiller is prepared by mixing boron nitride nanosheets, nano-alumina powder and graphene oxide in a weight ratio of 6:3:1.

[0033] The preparation method of the modified composite inorganic nanofiller is as follows: Five parts by weight of silane coupling agent KH-550 were dispersed in 500 parts by weight of 80% ethanol aqueous solution. After stirring and hydrolysis, 100 parts by weight of composite inorganic nanofiller were added and ultrasonically dispersed at 300W for 30 minutes. Then, the mixture was refluxed at 90℃ for 4 hours. After filtration, the mixture was washed five times with anhydrous ethanol and vacuum dried at 60℃ to constant weight. The resulting product was the modified composite inorganic nanofiller.

[0034] The coated modified silicon carbide micro powder is prepared by modifying silicon carbide micro powder as raw material; The preparation steps of the coated modified silicon carbide micro powder are as follows: Step 1: Weigh 50 parts by weight of silicon carbide micro powder and place it in a flask. Add 150 parts by weight of 5% hydrochloric acid solution and stir and reflux at 85°C for 24 hours. After filtration, dry at 105°C to constant weight. Grind through a 325-mesh sieve. The resulting product is called purified silicon carbide micro powder. Step 2: Weigh 50 parts by weight of purified silicon carbide micro powder and place it in a flask. Add 50 parts by weight of anhydrous ethanol and 1 part by weight of polyethylene glycol. Then, ultrasonically disperse the powder at 300W for 30 minutes. Stir and reflux at 80℃ for 5 hours. After filtration, rinse 5 times with deionized water. Dry the powder at 70℃ until constant weight. Grind the powder through a 325-mesh sieve to obtain the coated modified silicon carbide micro powder.

[0035] Modified rare earth oxides are prepared by modifying yttrium oxide, lanthanum oxide and cerium dioxide as raw materials; The preparation steps of the modified rare earth oxides are as follows: Step I: Weigh yttrium oxide, lanthanum oxide and cerium dioxide in a weight ratio of 17:3:1 and mix them. Then weigh 100 parts by weight of the mixture and disperse it in 500 parts by weight of anhydrous ethanol. The result is recorded as the dispersed component. Step II: Add 4 parts by weight of silane coupling agent KH-550 to the dispersion component, ultrasonically disperse at 300W for 1 hour, reflux at 85℃ for 3 hours, filter, wash 5 times with anhydrous ethanol, and vacuum dry at 60℃ to constant weight. The result is the modified rare earth oxide.

[0036] Corrosion-inhibiting microcapsules were prepared by coating molybdate / phosphate corrosion inhibitor components with a urea-formaldehyde prepolymer solution. The preparation steps of the corrosion-inhibiting microcapsules are as follows: Step A: Add 6 parts by weight of urea to 12 parts by weight of formaldehyde solution with a mass fraction of 37%, stir to dissolve, add triethanolamine dropwise to adjust the pH value to 9, heat to 70°C and keep the reaction at this temperature for 1 hour. The resulting solution is called urea-formaldehyde prepolymer solution. Step B: Weigh 14 parts by weight of sodium molybdate and 7 parts by weight of zinc phosphate and pour them into 35 parts by weight of deionized water. Stir at 500 r / min for 30 min. The resulting product is recorded as the molybdate / phosphate corrosion inhibitor component. Step C: Pour 100 parts by weight of cyclohexane and 2 parts by weight of emulsifier OP-10 into a flask, stir at 500 r / min for 30 min, then pour in the above molybdate / phosphate corrosion inhibitor component, and emulsify at 10000 r / min for 5 min. The resulting product is called water-in-oil microemulsion. Step D: After heating the water-in-oil microemulsion to 60°C, add 10 parts by weight of urea-formaldehyde prepolymer solution. Adjust the pH value to 4.5 with 10% hydrochloric acid solution and keep the reaction at this temperature for 4 hours. Then cool to room temperature and filter to collect the microcapsules. Wash them three times in sequence with cyclohexane, anhydrous ethanol and deionized water, and then vacuum dry them at 50°C for 12 hours. The resulting microcapsules are corrosion-inhibiting microcapsules.

[0037] A preparation process for a coating material for heat dissipation aluminum pipes, the preparation process is as follows: S1. Add 15 parts by weight of xylene and 8 parts by weight of butyl acetate to 50 parts by weight of silicone-modified acrylic resin. Stir at 400 r / min for 15 min, then add 20 parts by weight of modified composite inorganic nanofiller, 8 parts by weight of coated modified silicon carbide micro powder, and 6 parts by weight of modified rare earth oxide. Stir at 1000 r / min for 30 min, then disperse at 3000 r / min for 60 min. The resulting mixture is recorded as the base material component. S2. Grind the base material components three times using a three-roll mill and then pass them through an 800-mesh sieve. Next, add 3 parts by weight of corrosion-inhibiting microcapsules, 0.9 parts by weight of leveling agent, 0.6 parts by weight of defoamer, and 0.9 parts by weight of silane coupling agent KH-560. Stir at a stirring speed of 500 r / min for 30 min, then add xylene to adjust the viscosity to 60 mPa·s. Stir at the original stirring speed for 20 min and pass the mixture through a 100-mesh sieve. The resulting coating material is for heat dissipation aluminum pipes.

[0038] Example 3

[0039] This embodiment provides a coating material for heat dissipation aluminum pipes. The coating material for heat dissipation aluminum pipes comprises: organosilicon-modified acrylic resin, modified composite inorganic nanofiller, coated modified silicon carbide micropowder, modified rare earth oxide, and corrosion-inhibiting microcapsules. The organosilicon-modified acrylic resin is prepared by reacting methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate and silane coupling agent KH-570 as the main raw materials. The preparation steps of the organosilicon-modified acrylic resin are as follows: Step A: Weigh 40 parts by weight of methyl methacrylate, 35 parts by weight of butyl acrylate, 8 parts by weight of hydroxyethyl methacrylate, 3 parts by weight of hexafluorobutyl methacrylate, 4 parts by weight of acrylic acid, 6 parts by weight of silane coupling agent KH-570 and 1 part by weight of azobisisobutyronitrile and mix them. Stir at a stirring speed of 400 r / min for 15 min. The result is recorded as the monomer component. Step B: Pour 50 parts by weight of xylene into a flask, purge with nitrogen to remove oxygen, stir and heat to 85°C at a stirring speed of 400 r / min, add the above monomer components dropwise over 3 hours, keep warm for 2 hours, then add 0.4 parts by weight of azobisisobutyronitrile, and continue to keep warm for 1 hour. The resulting product is silicone-modified acrylic resin.

[0040] The modified composite inorganic nanofiller was prepared by modifying the composite inorganic nanofiller with silane coupling agent KH-550; The composite inorganic nanofiller is prepared by mixing boron nitride nanosheets, nano-alumina powder and graphene oxide in a weight ratio of 6:3:1.

[0041] The preparation method of the modified composite inorganic nanofiller is as follows: Four parts by weight of silane coupling agent KH-550 were dispersed in 450 parts by weight of 80% ethanol aqueous solution. After stirring and hydrolysis, 100 parts by weight of composite inorganic nanofiller were added and ultrasonically dispersed at 300W for 30 minutes. Then, the mixture was refluxed at 85℃ for 3 minutes. After filtration, the mixture was washed four times with anhydrous ethanol and vacuum dried at 60℃ to constant weight. The resulting product is the modified composite inorganic nanofiller.

[0042] The coated modified silicon carbide micro powder is prepared by modifying silicon carbide micro powder as raw material; The preparation steps of the coated modified silicon carbide micro powder are as follows: Step 1: Weigh 48 parts by weight of silicon carbide micro powder and place it in a flask. Add 150 parts by weight of 5% hydrochloric acid solution and stir and reflux at 85°C for 24 hours. After filtration, dry at 105°C to constant weight. Grind through a 325-mesh sieve. The resulting product is called purified silicon carbide micro powder. Step 2: Weigh 48 parts by weight of purified silicon carbide micro powder and place it in a flask. Add 50 parts by weight of anhydrous ethanol and 1 part by weight of polyethylene glycol. Then, ultrasonically disperse the powder at 300W for 30 minutes. Stir and reflux at 80℃ for 5 hours. After filtration, rinse 4 times with deionized water. Dry the powder at 70℃ to constant weight. Grind the powder through a 325-mesh sieve to obtain the coated modified silicon carbide micro powder.

[0043] Modified rare earth oxides are prepared by modifying yttrium oxide, lanthanum oxide and cerium dioxide as raw materials; The preparation steps of the modified rare earth oxides are as follows: Step I: Weigh yttrium oxide, lanthanum oxide and cerium dioxide in a weight ratio of 17:3:1 and mix them. Then weigh 100 parts by weight of the mixture and disperse it in 450 parts by weight of anhydrous ethanol. The result is recorded as the dispersed component. Step II: Add 3 parts by weight of silane coupling agent KH-550 to the dispersion component, ultrasonically disperse at 300W for 1 hour, reflux at 85℃ for 3 hours, filter, wash 4 times with anhydrous ethanol, and vacuum dry at 60℃ to constant weight. The result is the modified rare earth oxide.

[0044] Corrosion-inhibiting microcapsules were prepared by coating molybdate / phosphate corrosion inhibitor components with a urea-formaldehyde prepolymer solution. The preparation steps of the corrosion-inhibiting microcapsules are as follows: Step A: Add 5 parts by weight of urea to 11 parts by weight of formaldehyde solution with a mass fraction of 37%, stir to dissolve, add triethanolamine dropwise to adjust the pH value to 9, heat to 70°C and keep the reaction at this temperature for 1 hour. The resulting solution is called urea-formaldehyde prepolymer solution. Step B: Weigh 13 parts by weight of sodium molybdate and 7 parts by weight of zinc phosphate and pour them into 33 parts by weight of deionized water. Stir at 500 r / min for 30 min. The resulting product is recorded as the molybdate / phosphate corrosion inhibitor component. Step C: Pour 100 parts by weight of cyclohexane and 2 parts by weight of emulsifier OP-10 into a flask, stir at 500 r / min for 30 min, then pour in the above molybdate / phosphate corrosion inhibitor component, and emulsify at 9000 r / min for 5 min. The resulting product is called water-in-oil microemulsion. Step D: After heating the water-in-oil microemulsion to 58°C, add 10 parts by weight of urea-formaldehyde prepolymer solution. Adjust the pH value to 4.3 with 10% hydrochloric acid solution and keep the reaction at this temperature for 4 hours. Then cool to room temperature and filter to collect the microcapsules. Wash them three times in sequence with cyclohexane, anhydrous ethanol and deionized water, and then vacuum dry them at 45°C for 12 hours. The resulting microcapsules are corrosion-inhibiting microcapsules.

[0045] A preparation process for a coating material for heat dissipation aluminum pipes, the preparation process is as follows: S1. Add 13 parts by weight of xylene and 7 parts by weight of butyl acetate to 45 parts by weight of silicone-modified acrylic resin. Stir at 400 r / min for 15 min, then add 18 parts by weight of modified composite inorganic nanofiller, 7 parts by weight of coated modified silicon carbide micro powder, and 5 parts by weight of modified rare earth oxide. Stir at 900 r / min for 30 min, then disperse at 3000 r / min for 60 min. The resulting product is recorded as the base material component. S2. After grinding the base material components three times with a three-roll mill, pass them through an 800-mesh sieve. Then add 2 parts by weight of corrosion-inhibiting microcapsules, 0.7 parts by weight of leveling agent, 0.5 parts by weight of defoamer, and 0.7 parts by weight of silane coupling agent KH-560. Stir at a stirring speed of 500 r / min for 30 min, then add xylene to adjust the viscosity to 45 mPa·s. Stir at the original stirring speed for 15 min and pass through a 100-mesh sieve. The resulting coating material for heat dissipation aluminum pipes is the coating material.

[0046] Comparative Example 1 The coating material and its preparation process for heat dissipation aluminum pipes provided in this comparative example are generally the same as those in Example 1. The main difference is that the modified composite inorganic nanofiller in Example 1 is replaced with coated modified silicon carbide micropowder in this comparative example.

[0047] Comparative Example 2 The coating material and its preparation process for heat dissipation aluminum pipes provided in this comparative example are generally the same as those in Example 1. The main difference is that the modified silicon carbide micro powder in Example 1 is replaced with modified rare earth oxides.

[0048] Comparative Example 3 The coating material and its preparation process for heat dissipation aluminum pipes provided in this comparative example are generally the same as those in Example 1. The main difference is that the corrosion-inhibiting microcapsules in Example 1 are replaced with modified composite inorganic nanofillers.

[0049] Performance testing The coating materials for heat dissipation aluminum tubes prepared in Examples 1-3 and Comparative Examples 1-3 were labeled as Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. The performance of Examples 1-3 and Comparative Examples 1-3 was then tested. The specific testing methods and items are as follows: 1. The thermal conductivity of Examples 1-3 and Comparative Examples 1-3 was tested according to GB / T10295-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Heat Flow Meter Method", and the data obtained are recorded in Table 1. 2. The infrared emissivity of Examples 1-3 and Comparative Examples 1-3 was tested according to the standard GJB 2502.2-2006 "Test Methods for Thermal Control Coatings of Spacecraft", and the data obtained are recorded in Table 1; 3. The salt spray corrosion resistance time of Examples 1-3 and Comparative Examples 1-3 was tested according to the standard GB / T10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test". The data obtained are recorded in Table 1. 4. Examples 1-3 were soaked in solutions of different concentrations. After soaking for 12 hours, the release rate of molybdate ions was measured, and the data were recorded in Table 2.

[0050] Table 1 Performance Test Table

[0051] Table 2. Molybdate ion release rate

[0052] As shown in Table 1, the coating materials for heat dissipation aluminum pipes prepared in Examples 1-3 have superior heat dissipation and corrosion resistance compared to the comparative examples. This indicates that by adding modified composite inorganic nanofillers, coated modified silicon carbide micropowder, modified rare earth oxides, and corrosion-inhibiting microcapsules to the raw materials for preparing the coating materials for heat dissipation aluminum pipes, the present invention can improve the heat dissipation performance and durability of the coating materials, and has excellent promotional value.

[0053] As shown in Table 2, the corrosion-inhibiting microcapsules remain intact under neutral conditions with almost no leakage, while they rapidly rupture and release their contents under acidic conditions. This ensures that the corrosion inhibitor can reach the corrosion point in a timely manner and provide corrosion protection for the metal surface.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coating material for heat dissipation aluminum pipes, characterized in that, The coating material for the heat dissipation aluminum pipe comprises: organosilicon-modified acrylic resin, modified composite inorganic nanofiller, coated modified silicon carbide micropowder, modified rare earth oxide, and corrosion-inhibiting microcapsules. The organosilicon-modified acrylic resin is prepared by reacting methyl methacrylate, butyl acrylate, hydroxyethyl methacrylate and silane coupling agent KH-570 as the main raw materials. The modified composite inorganic nanofiller is prepared by modifying the composite inorganic nanofiller with silane coupling agent KH-550; The coated modified silicon carbide micro powder is prepared by modifying silicon carbide micro powder as raw material; The modified rare earth oxides are prepared by modifying yttrium oxide, lanthanum oxide and cerium dioxide as raw materials; The corrosion-inhibiting microcapsules were prepared by coating the molybdate / phosphate corrosion inhibitor components with a urea-formaldehyde prepolymer solution.

2. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The preparation steps of the organosilicon-modified acrylic resin are as follows: Step A: Weigh 35-45 parts by weight of methyl methacrylate, 30-40 parts by weight of butyl acrylate, 5-10 parts by weight of hydroxyethyl methacrylate, 2-3 parts by weight of hexafluorobutyl methacrylate, 3-5 parts by weight of acrylic acid, 5-6 parts by weight of silane coupling agent KH-570 and 0.8-1.2 parts by weight of azobisisobutyronitrile and mix them. Stir at a stirring speed of 300-400 r / min for 15 min. The result is recorded as the monomer component. Step B: Pour 40-60 parts by weight of xylene into a flask, purge with nitrogen to remove oxygen, stir and heat to 85°C at a stirring speed of 300-500 r / min, add the above monomer components dropwise over 3 hours, keep warm for 2 hours, then add 0.3-0.5 parts by weight of azobisisobutyronitrile, and continue to keep warm for 1 hour. The resulting product is silicone-modified acrylic resin.

3. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The composite inorganic nanofiller is prepared by mixing boron nitride nanosheets, nano-alumina powder and graphene oxide in a weight ratio of 6:3:

1.

4. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The preparation method of the modified composite inorganic nanofiller is as follows: Weigh 3-5 parts by weight of silane coupling agent KH-550 and disperse it in 400-500 parts by weight of 80% ethanol aqueous solution. After stirring and hydrolyzing, add 100 parts by weight of composite inorganic nanofiller and ultrasonically disperse it at 300W for 30 minutes. Then, reflux it at 80-90℃ for 2-4 hours. After filtration, wash it 3-5 times with anhydrous ethanol and vacuum dry it at 60℃ to constant weight. The result is the modified composite inorganic nanofiller.

5. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The preparation steps of the coated and modified silicon carbide micro powder are as follows: Step 1: Weigh 45-50 parts by weight of silicon carbide micro powder and place it in a flask. Add 150 parts by weight of 5% hydrochloric acid solution and stir and reflux at 85°C for 24 hours. After filtration, dry at 105°C to constant weight. Grind through a 325-mesh sieve. The resulting product is called purified silicon carbide micro powder. Step 2: Weigh 45-50 parts by weight of purified silicon carbide micro powder and place it in a flask. Add 50 parts by weight of anhydrous ethanol and 1 part by weight of polyethylene glycol, and then ultrasonically disperse it at 300W for 30 minutes. Stir and reflux at 80℃ for 5 hours. After filtration, rinse with deionized water 3-5 times, dry at 70℃ to constant weight, and grind it through a 325-mesh sieve to obtain coated modified silicon carbide micro powder.

6. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The preparation steps of the modified rare earth oxide are as follows: Step I: Weigh yttrium oxide, lanthanum oxide and cerium dioxide in a weight ratio of 17:3:1 and mix them. Then weigh 100 parts by weight of the mixture and disperse it in 400-500 parts by weight of anhydrous ethanol. The result is recorded as the dispersed component. Step II: Add 2-4 parts by weight of silane coupling agent KH-550 to the dispersion component, ultrasonically disperse at 300W for 1 hour, then reflux at 85℃ for 2-3 hours, filter, wash with anhydrous ethanol 3-5 times, and vacuum dry at 60℃ to constant weight. The result is the modified rare earth oxide.

7. The coating material for heat dissipation aluminum pipes according to claim 1, characterized in that, The preparation steps of the corrosion-inhibiting microcapsules are as follows: Step A: Add 5-6 parts by weight of urea to 10-12 parts by weight of formaldehyde solution with a mass fraction of 37%, stir to dissolve, add triethanolamine dropwise to adjust the pH value to 9, heat to 70℃ and keep the reaction at this temperature for 1 hour. The resulting solution is called urea-formaldehyde prepolymer solution. Step B: Weigh 13-14 parts by weight of sodium molybdate and 6-7 parts by weight of zinc phosphate and pour them into 30-35 parts by weight of deionized water. Stir at a stirring speed of 400-500 r / min for 30 min. The resulting product is recorded as the molybdate / phosphate corrosion inhibitor component. Step C: Pour 100 parts by weight of cyclohexane and 1-2 parts by weight of emulsifier into a flask, stir at a stirring speed of 400-500 r / min for 30 min, then pour in the above molybdate / phosphate corrosion inhibitor component, and emulsify at a high speed of 8000-10000 r / min for 5 min. The resulting product is called water-in-oil microemulsion. Step D: Heat the water-in-oil microemulsion to 55-60℃, add 10 parts by weight of urea-formaldehyde prepolymer solution, adjust the pH value to 4.0-4.5 with 10% hydrochloric acid solution, and keep the reaction at this temperature for 3-4 hours. Then cool to room temperature and filter to collect the microcapsules. Wash them three times in sequence with cyclohexane, anhydrous ethanol and deionized water, and then vacuum dry them at 40-50℃ for 12 hours. The resulting corrosion-inhibiting microcapsules are the microcapsules.

8. The preparation process of a coating material for heat dissipation aluminum pipes according to any one of claims 1-7, characterized in that, The preparation process is as follows: S1. Add 10-15 parts by weight of xylene and 5-8 parts by weight of butyl acetate to 40-50 parts by weight of silicone-modified acrylic resin, stir and mix well, then add 15-20 parts by weight of modified composite inorganic nanofiller, 5-8 parts by weight of coated modified silicon carbide micro powder, and 3-6 parts by weight of modified rare earth oxides. The mixture is then dispersed and the resulting product is recorded as the base material component. S2. Grind the base material components 2-3 times using a three-roll mill and then pass them through an 800-mesh sieve. Next, add 1-3 parts by weight of corrosion-inhibiting microcapsules, 0.5-0.9 parts by weight of leveling agent, 0.3-0.6 parts by weight of defoamer, and 0.5-0.9 parts by weight of silane coupling agent KH-560. After stirring evenly, add xylene to adjust the viscosity to the preset value. Continue stirring and pass the mixture through a 100-mesh sieve to obtain the coating material for heat dissipation aluminum pipes.

9. The preparation process of a coating material for heat dissipation aluminum pipes according to claim 8, characterized in that, The mixing method in S1 is to stir at a stirring speed of 300-400 r / min for 15 min. The dispersing method in S1 is to first stir at a stirring speed of 800-1000 r / min for 30 min, and then disperse at a high speed of 2000-3000 r / min for 60 min.

10. The preparation process of a coating material for heat dissipation aluminum pipes according to claim 8, characterized in that, The method for mixing evenly in S2 is to stir at a stirring speed of 400-500 r / min for 30 min, and the method for continuing to stir in S2 is to stir at the original stirring speed for 10-20 min.

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