Thermal insulation aluminum profile and preparation method thereof

Abstract

The application discloses a kind of heat insulation aluminum profile and preparation method thereof, belong to aluminum profile preparation technical field.The application is by electrostatic spraying heat insulation coating on the surface of aluminum profile, coating with epoxy resin as matrix, separate aluminum profile from outside environment, improve the corrosion resistance and heat insulation performance of aluminum profile;Compared with ordinary nano ATO, the prepared modified nano ATO is better compatible with epoxy resin matrix, the agglomeration phenomenon is obviously reduced, can greatly enhance the heat insulation performance of coating;The prepared modifier can significantly enhance the flame retardance and heat resistance of coating, also can promote the curing of epoxy resin, and graft on nano ATO, stable performance, not easy to fall off;Therefore, the aluminum profile prepared by the application has excellent heat insulation and corrosion resistance, and the coating sprayed on the surface of aluminum profile has stable and efficient flame retardance and heat resistance, and has important application value in the field of aluminum profile preparation technology.

Description

Technical Field

[0001] This invention belongs to the field of aluminum profile technology, specifically, it relates to a heat-insulating aluminum profile and its preparation method. Background Technology

[0002] Currently, building energy consumption accounts for 28-30% of my country's total energy consumption, and windows and doors account for 50% of building energy consumption. Therefore, the key to building energy conservation is to reduce the energy consumption of windows and doors. Common types of building windows and doors on the market include aluminum alloy windows and doors, plastic windows and doors, steel windows and doors, wooden windows and doors, and other types. Among them, aluminum alloy windows and doors are made of aluminum alloy profiles, which are a type of aluminum profile.

[0003] Aluminum profiles are metallic materials made primarily of aluminum through various processes such as casting, extrusion, and surface treatment, resulting in specific shapes and specifications. Based on composition, aluminum profiles can be divided into pure aluminum profiles and aluminum alloy profiles; based on application, they can be categorized into architectural aluminum profiles and industrial aluminum profiles. Architectural aluminum profiles are favored for their high performance, light weight, aesthetic appeal, good light transmission, durability, easy recycling and high reuse rate, and lack of environmental pollution. Due to their excellent performance, they are widely used in outdoor doors and balcony windows. However, aluminum is a metal with good thermal conductivity but relatively poor thermal insulation. Therefore, the focus and direction of aluminum alloy door and window technology development is to improve thermal insulation performance.

[0004] Currently, the common method to improve the thermal insulation performance of aluminum profiles is to spray coatings on their surface to isolate them from the external environment and prevent them from being directly heated, thereby improving their thermal insulation performance. However, existing coatings have poor heat resistance, and prolonged exposure to sunlight outdoors can easily lead to a decline in their performance and affect their service life. Moreover, common organic polymer coatings have poor flame retardant properties and are flammable materials. Therefore, it is urgent to solve these problems to meet the higher demands of the aluminum profile technology field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a heat-insulating aluminum profile and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a heat-insulating aluminum profile includes the following steps:

[0008] A1. After wiping the surface of the aluminum profile with acetone, immerse it in a hexadecyltrimethylammonium bromide aqueous solution (4% by mass) to degrease the surface and obtain a degreased aluminum profile.

[0009] A2. Spray micro-etching solution onto the surface of the degreased aluminum profile, clean it, dry it, and then put it into an oxidation tank for anodizing. After oxidation, wash it with water and dry it to obtain the pretreated aluminum profile.

[0010] A3. Apply heat-insulating coating to the surface of the pre-treated aluminum profile using electrostatic spraying. After spraying, place it in a curing chamber for curing. Once curing is complete, allow it to cool naturally to room temperature to obtain the heat-insulating aluminum profile.

[0011] Further, in step A2, the micro-etching solution is prepared by mixing hydrochloric acid, phosphoric acid, triethanolamine, diamine bicarbonate and water in a mass ratio of 1:1-3:2-5:1-4:20-30.

[0012] By degreasing and micro-etching the surface of aluminum profiles, the oxide film on the surface can be removed, and a microporous structure can be formed on the surface of the aluminum profiles to facilitate the adhesion of the sprayed coating during subsequent spraying. Then, anodizing produces a more uniform oxide film, which improves the corrosion resistance of the aluminum profile substrate. Finally, by using electrostatic spraying, a smooth and uniform coating can be obtained, and the utilization rate of the coating is high, saving costs.

[0013] Furthermore, the heat-insulating coating is prepared through the following steps:

[0014] Bisphenol epoxy resin, modified nano-ATO, curing accelerator, ultraviolet absorber and leveling agent are added to a high-speed mixer and mixed for 15 minutes to ensure that all components are fully and evenly mixed. Then, the mixture is poured into a twin-screw extruder for melt blending and extrusion. After discharge, the material is cooled to room temperature by cold roller pressing, and then pulverized at high speed and passed through a 200-mesh sieve to obtain a heat insulation coating.

[0015] Furthermore, the raw materials are as follows by weight: 60-80 parts bisphenol epoxy resin, 10-20 parts modified nano ATO, 0.5-1.5 parts curing accelerator, 4-6 parts ultraviolet absorber, and 2-4 parts leveling agent.

[0016] Furthermore, the curing accelerator is one of 2-methylimidazole and 3-methylimidazole.

[0017] Furthermore, the ultraviolet absorber is one of ultraviolet absorber UV-531 and ultraviolet absorber UV-326.

[0018] Furthermore, the leveling agent is one of benzoin, hydrogenated castor oil, cellulose acetate butyrate, and epoxidized soybean oil.

[0019] The resulting heat-insulating coating uses epoxy resin as a matrix, which can effectively isolate aluminum profiles from the external environment, improve the heat insulation performance of aluminum profiles, and also endow the coating with excellent corrosion resistance; the addition of ultraviolet absorbers can improve the coating's resistance to photoaging.

[0020] Furthermore, the modified nano-ATO is prepared through the following steps:

[0021] B1. Add nano-ATO to ethanol, stir, ultrasonically disperse evenly, add silane coupling agent KH-560, mix evenly, react at 55℃ for 6h, filter, wash 2-3 times with anhydrous ethanol, dry, and obtain pre-modified nano-ATO.

[0022] B2. Add N,N-dimethylformamide (DMF) and pre-modified nano-ATO to a flask, sonicate for 15 min to disperse evenly, add modifier, slowly heat to 95℃, turn on magnetic stirring (1200 r / min), stir for 6 h, then stop heating, let stand, and after the temperature in the reaction flask drops to 30℃, filter, wash 3-4 times with anhydrous ethanol, freeze dry to obtain modified nano-ATO.

[0023] Furthermore, in step A1, the ratio of nano-ATO, ethanol, and KH-560 is 1g:100mL:4.5g.

[0024] Furthermore, in step A2, the ratio of DMF, pre-modified nano-ATO, and modifier is 100mL:1g:5.5g.

[0025] Nano-ATO exhibits good infrared blocking properties. Pre-modifying nano-ATO with KH-560 by attaching epoxy groups allows it to undergo a ring-opening reaction with the amino groups on the modifier, resulting in modified nano-ATO. The modified nano-ATO is then grafted with a modifier through chemical bonding, forming an organic layer on its surface. This improves the surface hydrophobicity of the nano-ATO and enhances the interfacial compatibility between the nano-ATO and the epoxy resin matrix. This promotes uniform dispersion of the modified nano-ATO in the matrix, reduces agglomeration, and allows the modified nano-ATO to fully exert its performance, significantly enhancing the thermal insulation properties of the coating. Furthermore, the nano-ATO grafting modifier effectively prevents modifier migration and exudation, ensuring the longevity of all performance characteristics.

[0026] Furthermore, the modifier is prepared through the following steps:

[0027] S1. In a three-necked flask equipped with a stirring and reflux apparatus, phosphorus oxychloride, pentaerythritol, and toluene were stirred until homogeneous. Nitrogen gas was introduced, and the reaction temperature was controlled at 70°C. After reacting for 4 hours, the temperature was raised to 110°C, and the reaction was refluxed until no hydrogen chloride gas was produced. The reaction was then completed. The mixture was cooled to room temperature, washed with dichloromethane, and the solvent was removed by vacuum distillation. The mixture was then dried under vacuum to obtain intermediate 1. The ratio of phosphorus oxychloride, pentaerythritol, and toluene was 32.4 g: 13.6 g: 100 mL.

[0028] Phosphorus oxychloride and pentaerythritol undergo an esterification reaction, with phosphorus oxychloride in excess, to give intermediate 1; the specific reaction process is shown below:

[0029]

[0030] S2. At room temperature and under nitrogen protection, 2-aminobenzimidazole, intermediate 1, triethylamine, and toluene were mixed in a three-necked flask equipped with a stirrer. After stirring until homogeneous, the temperature of the reaction system was raised to 60°C and maintained for 4 hours. After the reaction was complete, the mixture was filtered, and part of the solvent was removed by rotary evaporation. Then, it was purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 4:3). The eluent was removed by rotary evaporation to obtain intermediate 2. The ratio of 2-aminobenzimidazole, intermediate 1, triethylamine, and toluene was 13.3 g: 31.3 g: 15 mL: 100 mL.

[0031] The amino group on 2-aminobenzimidazole undergoes nucleophilic substitution with the chloro group of intermediate 1. By controlling the molar ratio of the two to be close to 1:1 and with intermediate 1 in slight excess, only one -Cl group on intermediate 1 participates in the reaction. Triethylamine removes the hydrogen chloride generated in the reaction to obtain intermediate 2. The specific reaction process is shown below:

[0032]

[0033] S3. In a three-necked flask equipped with a stirrer, intermediate 2, hydroquinone, triethylamine, and toluene are mixed and stirred until homogeneous. The mixture is then slowly heated to 70°C and reacted for 6 hours. Once the reaction is complete, triethylamine hydrochloride is removed by filtration, and some of the solvent is removed by vacuum distillation. The mixture is then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate in a volume ratio of 3:2). The eluent is removed by rotary evaporation to obtain intermediate 3. The ratio of intermediate 2, hydroquinone, triethylamine, and toluene is 39.3 g: 13.1 g: 15 mL: 100 mL.

[0034] Triethylamine acts as an acid-binding agent to remove the hydrogen chloride generated in the reaction. Intermediate 2 undergoes a substitution reaction with hydroquinone. By controlling the molar ratio of the two to be close to 1:1 and with a slight excess of hydroquinone, only one phenolic hydroxyl group on the hydroquinone participates in the reaction, yielding intermediate 3. The specific reaction process is shown below:

[0035]

[0036] S4. Mix intermediate 3 and toluene, and add them to a three-necked round-bottom flask equipped with a thermometer, a magnetic stirring system, and a spherical condenser. Under ice-water bath conditions, add formaldehyde solution (28% by mass) dropwise, and stir continuously for 45 min. Then add ethylenediamine, control the reaction temperature at 65℃, and reflux for 8 h. After the reaction is complete, cool to room temperature, remove the solvent by rotary evaporation, add toluene and deionized water to separate the layers, take the upper organic phase, wash it successively with saturated sodium carbonate, saturated sodium bicarbonate, and saturated brine, separate the upper organic phase, and dry it to obtain the modifier. The ratio of intermediate 3, toluene, formaldehyde solution, and ethylenediamine is 47.6 g: 100 mL: 20 mL: 8.4 g.

[0037] Intermediate 3 reacts with ethylenediamine. By controlling the molar ratio of the two to be close to 1:1 and with ethylenediamine in slight excess, the modifier is obtained. The specific reaction process is shown below:

[0038]

[0039] The prepared modifier molecule contains an amino group at one end, which can chemically bond with the pre-modified nano-ATO, improving the stability of the modifier molecule. In addition, the modifier molecule also contains spirocyclic phosphate, benzimidazole, and benzoxazine structures. Among them, spirocyclic phosphate has good flame retardant effect and has a stable six-membered heterocyclic structure. During combustion, the pentaerythritol skeleton forms a char protective layer, inhibiting further combustion of the matrix. The introduced benzimidazole is a nitrogen-rich heterocyclic ring with good thermal stability. When exposed to fire, it releases flame-retardant gas to dilute the oxygen concentration around the pyrolysis zone. At the same time, as the flame-retardant nitrogen gas volatilizes, it carries most of the heat, further improving the flame retardant performance of the matrix. Moreover, the pyridine nitrogen in the benzimidazole structure can react with the highly reactive epoxy groups in the epoxy resin, promoting the curing of the epoxy resin and forming a cross-linked three-dimensional network macromolecular polymer in the epoxy resin matrix, improving the performance of the epoxy resin matrix. Finally, the introduced benzoxazine can enhance the heat resistance of the matrix.

[0040] The beneficial effects of this invention are:

[0041] 1. The aluminum profile obtained by the present invention can form a microporous structure on the surface of the aluminum profile by degreasing and micro-etching, which facilitates the improvement of the adhesion of the sprayed coating during subsequent spraying.

[0042] 2. Electrostatic spraying of heat-insulating coating on the surface of aluminum profiles. The coating uses epoxy resin as a base to isolate the aluminum profiles from the external environment, thereby improving the corrosion resistance and heat insulation performance of the aluminum profiles.

[0043] 3. The modified nano-ATO obtained has better compatibility with epoxy resin matrix and significantly reduced agglomeration compared with ordinary nano-ATO, which can greatly enhance the thermal insulation performance of the coating.

[0044] 4. The prepared modifier can significantly enhance the flame retardancy and heat resistance of the coating, promote the curing of epoxy resin, and is grafted onto nano-ATO, exhibiting stable performance and not easily falling off.

[0045] Therefore, the aluminum profiles prepared by this invention have excellent heat insulation and corrosion resistance, and the coatings sprayed on the surface of the aluminum profiles have stable and efficient flame retardancy and heat resistance, which has important application value in the field of aluminum profile preparation technology. Detailed Implementation

[0046] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] Preparation of modifiers:

[0049] S1. In a three-necked flask equipped with a stirring and reflux apparatus, 32.4 g of phosphorus oxychloride, 13.6 g of pentaerythritol and 100 mL of toluene were stirred evenly, nitrogen gas was introduced, and the reaction temperature was controlled at 70 °C. After reacting for 4 h, the temperature was raised to 110 °C and refluxed until no hydrogen chloride gas was produced. The reaction was then completed, cooled to room temperature, washed with dichloromethane, the solvent was removed by vacuum distillation, and dried under vacuum to obtain intermediate 1.

[0050] S2. At room temperature and under nitrogen protection, 13.3 g of 2-aminobenzimidazole, 31.3 g of intermediate 1, 15 mL of triethylamine, and 100 mL of toluene were mixed in a three-necked flask equipped with a stirrer. After stirring until homogeneous, the temperature of the reaction system was raised to 60 °C and maintained for 4 h. After the reaction was completed, the mixture was filtered, and part of the solvent was removed by rotary evaporation. Then, it was purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 4:3). The eluent was removed by rotary evaporation to obtain intermediate 2.

[0051] S3. In a three-necked flask equipped with a stirrer, 39.3 g of intermediate 2, 13.1 g of hydroquinone, 15 mL of triethylamine and 100 mL of toluene were mixed and stirred until homogeneous. The mixture was then slowly heated to 70 °C and reacted for 6 h. After the reaction was complete, the triethylamine hydrochloride was removed by filtration, and some of the solvent was removed by vacuum distillation. The mixture was then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 3:2). The eluent was removed by rotary evaporation to obtain intermediate 3.

[0052] S4. Mix 47.6 g of intermediate 3 with 100 mL of toluene and add it to a three-necked round-bottom flask equipped with a thermometer, a magnetic stirring system and a spherical condenser. Under ice-water bath conditions, add 20 mL of formaldehyde solution (28% by mass) dropwise and stir continuously for 45 min. Then add 8.4 g of ethylenediamine and control the reaction temperature at 65 °C. Reflux for 8 h until the reaction is complete. Cool to room temperature and remove the solvent by rotary evaporation. Add toluene and deionized water to separate the layers. Take the upper organic phase and wash it successively with saturated sodium carbonate, saturated sodium bicarbonate and saturated brine. Separate the upper organic phase and dry it to obtain the modifier.

[0053] Example 2

[0054] Preparation of modifiers:

[0055] S1. In a three-necked flask equipped with a stirring and reflux apparatus, 64.8 g of phosphorus oxychloride, 27.2 g of pentaerythritol and 200 mL of toluene were stirred evenly, nitrogen gas was introduced, and the reaction temperature was controlled at 70 °C. After reacting for 4 h, the temperature was raised to 110 °C and refluxed until no hydrogen chloride gas was produced. The reaction was then completed, cooled to room temperature, washed with dichloromethane, the solvent was removed by vacuum distillation, and dried under vacuum to obtain intermediate 1.

[0056] S2. At room temperature and under nitrogen protection, 26.6 g of 2-aminobenzimidazole, 62.6 g of intermediate 1, 30 mL of triethylamine, and 200 mL of toluene were mixed in a three-necked flask equipped with a stirrer. After stirring until homogeneous, the temperature of the reaction system was raised to 60 °C and maintained for 4 h. After the reaction was completed, the mixture was filtered, and part of the solvent was removed by rotary evaporation. Then, it was purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 4:3). The eluent was removed by rotary evaporation to obtain intermediate 2.

[0057] S3. In a three-necked flask equipped with a stirrer, 78.6 g of intermediate 2, 26.2 g of hydroquinone, 30 mL of triethylamine and 200 mL of toluene were mixed and stirred until homogeneous. The mixture was then slowly heated to 70 °C and reacted for 6 h. After the reaction was complete, the triethylamine hydrochloride was removed by filtration, and some of the solvent was removed by vacuum distillation. The mixture was then purified by column chromatography (using a mixed solvent of benzene and ethyl acetate as the eluent, with a volume ratio of 3:2). The eluent was removed by rotary evaporation to obtain intermediate 3.

[0058] S4. Mix 95.2g of intermediate 3 and 200mL of toluene, and add the mixture to a three-necked round-bottom flask equipped with a thermometer, a magnetic stirring system, and a spherical condenser. Under ice-water bath conditions, add 40mL of formaldehyde solution (28% by mass) dropwise, and stir continuously for 45min. Then add 16.8g of ethylenediamine, control the reaction temperature at 65℃, and reflux for 8h. After the reaction is complete, cool to room temperature, remove the solvent by rotary evaporation, add toluene and deionized water to separate the layers, take the upper organic phase, wash it successively with saturated sodium carbonate, saturated sodium bicarbonate, and saturated brine, separate the upper organic phase, and dry it to obtain the modifier.

[0059] Example 3

[0060] Preparation of modified nano-ATO:

[0061] B1. Add 1g of nano-ATO to 100mL of ethanol, stir, and ultrasonically disperse evenly. Add 4.5g of silane coupling agent KH-560, mix evenly, react at 55℃ for 6h, filter, wash 3 times with anhydrous ethanol, and dry to obtain pre-modified nano-ATO.

[0062] B2. Add 100 mL of N,N-dimethylformamide and 1 g of pre-modified nano-ATO to a flask, sonicate for 15 min to disperse evenly, add 5.5 g of the modifier prepared in Example 1, slowly heat to 95 °C, turn on magnetic stirring (1200 r / min), stir for 6 h and then stop heating, let stand, and after the temperature in the reaction flask drops to 30 °C, filter, wash 3 times with anhydrous ethanol, freeze dry to obtain modified nano-ATO.

[0063] Example 4

[0064] Preparation of modified nano-ATO:

[0065] B1. Add 2g of nano-ATO to 200mL of ethanol, stir, and ultrasonically disperse evenly. Add 9.0g of silane coupling agent KH-560, mix evenly, react at 55℃ for 6h, filter, wash twice with anhydrous ethanol, and dry to obtain pre-modified nano-ATO.

[0066] B2. Add 200 mL of N,N-dimethylformamide and 2 g of pre-modified nano-ATO to a flask, sonicate for 15 min to disperse evenly, add 11.0 g of the modifier prepared in Example 2, slowly heat to 95 °C, turn on magnetic stirring (1200 r / min), stir for 6 h and then stop heating, let stand, and after the temperature in the reaction flask drops to 30 °C, filter, wash 4 times with anhydrous ethanol, freeze dry to obtain modified nano-ATO.

[0067] Example 5

[0068] Preparation of heat-insulating coatings:

[0069] 60g of bisphenol epoxy resin (epoxy value 0.56), 10g of modified nano-ATO prepared in Example 3, 0.5g of 2-methylimidazole, 4g of UV absorber UV-531 and 2g of benzoin were added to a high-speed mixer and mixed for 15 minutes to ensure that all components were fully and evenly mixed. The mixture was then poured into a twin-screw extruder for melt blending and extrusion. After discharge, the mixture was cooled to room temperature by cold roller pressing, pulverized at high speed and passed through a 200-mesh sieve to obtain a heat-insulating coating.

[0070] Example 6

[0071] Preparation of heat-insulating coatings:

[0072] 70g of bisphenol epoxy resin (epoxy value 0.56), 15g of modified nano-ATO prepared in Example 4, 1g of 3-methylimidazole, 5g of UV absorber UV-326 and 3g of epoxidized soybean oil were added to a high-speed mixer and mixed for 15 minutes to ensure that all components were fully mixed and uniform. The mixture was then poured into a twin-screw extruder for melt blending and extrusion. After discharge, the mixture was cooled to room temperature by cold roller pressing, and then pulverized at high speed and passed through a 200-mesh sieve to obtain a heat insulation coating.

[0073] Example 7

[0074] Preparation of heat-insulating coatings:

[0075] 80g of bisphenol epoxy resin (epoxy value 0.56), 20g of modified nano-ATO prepared in Example 4, 1.5g of 3-methylimidazole, 6g of UV absorber UV-326 and 4g of epoxidized soybean oil were added to a high-speed mixer and mixed for 15 minutes to ensure that all components were fully mixed and uniform. The mixture was then poured into a twin-screw extruder for melt blending and extrusion. After discharge, the mixture was cooled to room temperature by cold roller pressing, and then pulverized at high speed and passed through a 200-mesh sieve to obtain a heat insulation coating.

[0076] Example 8

[0077] Preparation of thermally insulated aluminum profiles:

[0078] A1. After wiping the surface of the aluminum profile with acetone, immerse it in a hexadecyltrimethylammonium bromide aqueous solution (4% by mass) to degrease the surface and obtain a degreased aluminum profile.

[0079] A2. Spray micro-etching solution onto the surface of the degreased aluminum profile, clean it, dry it, and then put it into an oxidation tank for anodizing. After oxidation, wash it with water and dry it to obtain the pretreated aluminum profile.

[0080] A3. Electrostatic spraying was applied to the surface of the pretreated aluminum profile. The heat-insulating coating prepared in Example 7 was sprayed. The compressed air pressure was 0.5 MPa, the electrostatic spraying voltage was 40 KV, and the distance between the spray gun and the workpiece was 150 mm. After spraying, the profile was placed in a curing chamber for curing. The curing temperature was 200°C and the curing time was 1 hour. After curing, the profile was allowed to cool naturally to room temperature to obtain the heat-insulating aluminum profile.

[0081] The micro-etching solution is prepared by mixing hydrochloric acid, phosphoric acid, triethanolamine, diamine bicarbonate and water in a mass ratio of 1:3:5:4:30.

[0082] Comparative Example 1

[0083] The modified nano-ATO in Example 7 was replaced with the same mass of ordinary nano-ATO, and the remaining steps were the same as in Example 7 to obtain the coating.

[0084] Comparative Example 2

[0085] Use commercially available heat insulation coatings.

[0086] Examples 5, 6, and 7, and Comparative Examples 1 and 2, were subjected to the following performance tests according to different testing standards:

[0087] The adhesion of the samples before and after standing at 160℃ for 12 hours was determined according to the national standard GB / T 9286-2021 "Cross-cut test method for paints and varnishes".

[0088] The acid and alkali resistance was determined according to the national standard GB / T 1763 "Determination of Chemical Resistance of Coatings".

[0089] The fire resistance time and mass loss of the samples were determined before and after 180 days of storage at room temperature using the national standard GB 12441-2005 "Decorative Fire Retardant Coatings".

[0090] Thermal conductivity was determined according to the national standard GB / T 10294 (the lower the coefficient, the better the thermal insulation performance).

[0091] The measurement results are shown in the table below:

[0092]

[0093] As can be seen from the table above, the coating prepared in the embodiments of the present invention has excellent heat insulation, flame retardancy, heat resistance and corrosion resistance, and its performance is stable over a long period of time. Spraying it on the surface of aluminum profiles can significantly enhance the performance of aluminum profiles and has important application value in the field of aluminum profile preparation technology.

[0094] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a heat-insulating aluminum profile, characterized in that, Includes the following steps: A1. After wiping the surface of the aluminum profile with acetone, immerse it in an aqueous solution of hexadecyltrimethylammonium bromide to degrease the surface and obtain a degreased aluminum profile. A2. Spray micro-etching solution onto the surface of the degreased aluminum profile, clean it, dry it, and then put it into an oxidation tank for anodizing. After oxidation, wash it and dry it to obtain the pretreated aluminum profile. A3. Electrostatic spraying is applied to the surface of the pretreated aluminum profile to apply a heat-insulating coating. After spraying, the coating is cured, and after curing, it is allowed to cool naturally to obtain a heat-insulating aluminum profile. The modifier is prepared through the following steps: S1. After stirring phosphorus oxychloride, pentaerythritol and toluene evenly, nitrogen gas was introduced and the reaction was carried out at 70°C for 4 hours. Then the temperature was raised to 110°C and the reaction was refluxed until no hydrogen chloride gas was produced. The reaction was then completed, cooled to room temperature, washed, distilled under reduced pressure, and dried to obtain intermediate 1. S2. At room temperature and under nitrogen protection, 2-aminobenzimidazole, intermediate 1, triethylamine and toluene were mixed and stirred evenly. The mixture was then kept at 60°C for 4 hours. After the reaction was completed, the mixture was filtered, rotary evaporated, purified by column chromatography, and rotary evaporated again to obtain intermediate 2. S3. Mix intermediate 2, hydroquinone, triethylamine and toluene and stir evenly. React at 70°C for 6 hours. After the reaction is complete, filter, distill under reduced pressure, purify by column chromatography, and rotary evaporate to obtain intermediate 3. S4. Mix intermediate 3 and toluene, add formaldehyde solution dropwise, and stir continuously for 45 min. Then add ethylenediamine and reflux at 65 °C for 8 h. After the reaction is complete, cool to room temperature, rotary evaporate, add toluene and deionized water to separate the layers, take the upper organic phase, wash, separate the upper organic phase, dry, and obtain the modifier. The heat-insulating coating mentioned in step A3 is prepared through the following steps: Bisphenol epoxy resin, modified nano ATO, curing accelerator, ultraviolet absorber and leveling agent are mixed, then poured into a twin-screw extruder for melt blending and extrusion, cooled, crushed and sieved to obtain heat insulation coating; The modified nano-ATO is prepared through the following steps: B1. Add nano-ATO to ethanol, stir, ultrasonically disperse evenly, add silane coupling agent KH-560, mix evenly, react at 55℃ for 6h, filter, wash, and dry to obtain pre-modified nano-ATO. B2. Add N,N-dimethylformamide and pre-modified nano-ATO to a flask, sonicate for 15 min to disperse evenly, add modifier, slowly heat to 95℃, turn on magnetic stirring, stir for 6 h, then stop heating, let stand, filter, wash, and dry to obtain modified nano-ATO.

2. The method for preparing a heat-insulating aluminum profile according to claim 1, characterized in that, In step S1, the ratio of phosphorus oxychloride, pentaerythritol, and toluene is 32.4 g: 13.6 g: 100 mL.

3. The method for preparing a heat-insulating aluminum profile according to claim 1, characterized in that, In step S2, the ratio of 2-aminobenzimidazole, intermediate 1, triethylamine, and toluene is 13.3g:31.3g:15mL:100mL.

4. The method for preparing a heat-insulating aluminum profile according to claim 1, characterized in that, In step S3, the ratio of intermediate 2, hydroquinone, triethylamine, and toluene is 39.3g:13.1g:15mL:100mL.

5. The method for preparing a heat-insulating aluminum profile according to claim 1, characterized in that, In step S4, the ratio of intermediate 3, toluene, formaldehyde solution, and ethylenediamine is 47.6g:100mL:20mL:8.4g.

6. The method for preparing a heat-insulating aluminum profile according to claim 1, characterized in that, The raw materials are as follows by weight: 60-80 parts bisphenol epoxy resin, 10-20 parts modified nano ATO, 0.5-1.5 parts curing accelerator, 4-6 parts ultraviolet absorber, and 2-4 parts leveling agent.

7. A heat-insulating aluminum profile, characterized in that, Prepared according to the method according to any one of claims 1-6.

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