A high-hardness, corrosion-resistant aluminum curtain wall panel and its preparation method

Abstract

This invention relates to the field of aluminum plate surface treatment technology, specifically to a high-hardness, corrosion-resistant curtain wall aluminum plate and its preparation method, comprising the following processes: S1. Anodizing: Anodizing an aluminum plate in an electrolyte solution; the electrolyte solution includes sulfuric acid, boric acid, cerium sulfate, and polymethyl methacrylate; S2. Sealing treatment: Sealing the aluminum plate in a sealing solution under negative pressure; S3. Encapsulation treatment: Immersing the aluminum plate in a sealing solution to obtain the curtain wall aluminum plate. This invention uses sulfuric acid, boric acid, cerium sulfate, and polymethyl methacrylate as electrolyte components for anodizing, reducing the solubility of the oxide film, alleviating corrosion at defects in the aluminum plate, allowing aluminum ions to accumulate on the aluminum plate surface, attracting anions, reducing reaction resistance, inhibiting the large-scale generation of oxygen, and generating a high-thickness oxide film on the aluminum plate surface. This improves the uniformity and density of the oxide film, enhancing its corrosion resistance, wear resistance, and microhardness, thus improving the hardness and corrosion resistance of the resulting curtain wall aluminum plate.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for aluminum curtain wall panels, specifically to a high-hardness, corrosion-resistant aluminum curtain wall panel and its preparation method. Background Technology

[0002] Aluminum is the most abundant metallic element in the Earth's crust, possessing excellent ductility and electrical and thermal conductivity. Aluminum alloys exhibit low density, high electrical resistance, high electrical conductivity, high thermal conductivity, and excellent corrosion resistance. Due to the superior comprehensive physical and chemical properties of aluminum and its alloys, they have important applications in numerous industries such as cookware, power, construction, electronics, shipbuilding, and aerospace. Aluminum and its alloys readily form an oxide film several nanometers thick on their surface in air. This oxide film prevents further oxidation of the aluminum alloy matrix by oxygen, thus providing aluminum and its alloys with a certain degree of corrosion resistance under natural conditions. Curtain walls are the exterior cladding of buildings, requiring a certain degree of flexibility relative to the main structure. To reduce building weight, aluminum panels are often used as curtain wall materials. However, the naturally formed oxide film on aluminum panels is generally amorphous, relatively thin, and has poor mechanical strength. In highly corrosive environments or when this oxide film is damaged, the aluminum alloy surface will be further corroded, failing to meet the protection requirements for aluminum and its alloys. Therefore, we propose a high-hardness, corrosion-resistant aluminum curtain wall panel and its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide a high-hardness, corrosion-resistant aluminum curtain wall panel and its preparation method, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing high-hardness corrosion-resistant aluminum curtain wall panels, comprising the following processes:

[0005] S1. Anodizing: An aluminum plate is used as the anode and pure aluminum as the cathode, and the plates are placed in an electrolyte to perform anodizing. The electrolyte includes the following components: sulfuric acid, boric acid, cerium sulfate, and polymethyl methacrylate.

[0006] S2. Sealing treatment: The aluminum plate obtained in step S1 is placed in a sealing liquid and sealed under negative pressure. The sealing liquid includes the following components: nickel acetate, accelerator, complexing agent, passivating agent and dust suppressant.

[0007] S3. Sealing treatment: The aluminum plate obtained in step S2 is placed in a sealing liquid, dipped, and dried to obtain a curtain wall aluminum plate; the sealing liquid includes the following components: silica sol, waterborne polysiloxane, waterborne polyurethane, and graphene oxide.

[0008] Furthermore, the aluminum plate is a 7075 aluminum plate, comprising the following mass fractions: Zn: 5.3–5.6%, Mg: 2.1–2.9%, Cu: 1.50–2.0%, Cr: 0.18–0.23%, Ni: 0.5–1.0%, Si < 0.05%, Fe < 0.07%, Mn < 0.25%, Ti < 0.06%; total other impurities ≤ 0.15%, individual impurities ≤ 0.05%, and the balance is Al.

[0009] Furthermore, the S1. anodizing process also includes a pretreatment, specifically:

[0010] (1) Heat treatment:

[0011] Solution treatment: Place the aluminum plate in a furnace, heat it to 475℃, hold it for 24 hours, remove it, quench it, and cool it to room temperature;

[0012] Annealing: Heat to 110℃ and hold for 8 hours; heat to 150℃ and hold for 8 hours, then remove and air cool.

[0013] (2) Pretreatment:

[0014] Sand with 800#, 1200#, and 2000# sandpaper in sequence, remove oil with acetone for 30-50 seconds, and then rinse with water;

[0015] Alkaline washing: Immerse in a mixed solution of sodium hydroxide and sodium carbonate at 60-70℃ for 1-7 minutes; wash with water; the mass concentration of sodium hydroxide in the mixed solution is 35-40 g / L and the mass concentration of sodium carbonate is 15-20 g / L.

[0016] Pickling: Immerse in nitric acid solution for 30-60 seconds; wash with water; dry with nitrogen; the mass concentration of nitric acid solution is 10-20%.

[0017] In the above technical solution, the aluminum plate contains the metallic element nickel, which can undergo a eutectic reaction with aluminum to generate the high-melting-point phase Al3Ni, characterized by high hardness. Nickel preferentially precipitates during post-metallurgical solidification, inhibiting grain boundary movement in molten aluminum and hindering grain growth, thus refining the grains. Simultaneously, as a hard and brittle stable phase in the aluminum plate, it hinders dislocation movement, effectively improving the hardness and tensile strength of the aluminum plate. After casting and cooling, the aluminum plate undergoes solution treatment at 475℃ for 24 hours followed by water quenching and aging treatment at 110℃ for 8 hours and then at 150℃ for 8 hours. This process clarifies the grain boundary structure, refines the Al3Ni phase, and induces the precipitation, growth, and transformation of the MgZn2 phase into the η phase, discontinuously distributed along the grain boundaries. This increases the number and size of the precipitated phases, resulting in a more uniform microstructure and inhibiting crack initiation. The resulting aluminum alloy plate exhibits high hardness, strength, and corrosion resistance, and also possesses superior electrochemical properties, improving the subsequent anodizing process.

[0018] As the nickel content increases, the content of the hard and brittle Al3Ni phase also increases. A large amount of eutectic aggregates at the grain boundaries, gradually increasing in size and thickening the grain boundaries. While increasing hardness, this reduces the strength, elongation, and corrosion resistance of the aluminum alloy sheet. Before anodizing, the aluminum sheet undergoes surface pretreatment to reduce surface roughness, remove surface contaminants, and activate the surface to promote the orderly progress of the anodizing process.

[0019] Furthermore, the S1. anodizing includes the following process:

[0020] An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution at a temperature of 15–35°C and a current density of 1–4 A / dm³. 2 Under these conditions, oxidize for 18–28 min;

[0021] The electrolyte comprises the following components by weight: 160–200 g / L sulfuric acid, 5–10 g / L boric acid, 30–50 g / L cerium sulfate, and 3–5 g / L polymethyl methacrylate.

[0022] In the above technical solution, (1) the electrolyte uses sulfuric acid and boric acid as a mixed acid. Boric acid can reduce the solubility of sulfuric acid in the oxide film, improve the uniformity of the oxide film produced by anodizing, increase its density, and effectively improve the corrosion resistance, wear resistance and microhardness of the oxide film. (2) The electrolyte contains polymethyl methacrylate, an organic compound that preferentially adsorbs onto the surface defects of the aluminum plate. This prevents the oxidation reaction to a certain extent, prevents oxygen atoms from preferentially forming an oxide film at the defects, alleviates the solution corrosion of the oxide film by the electrolyte, makes the oxide film more uniform overall, and reduces the surface roughness. It can generate electrostatic attraction with aluminum ions on the surface of the aluminum plate and provide electrons to its pore orbitals, so that polymethyl methacrylate forms a stable chemical adsorption on the metal surface, combines with aluminum ions, reacts to form a stable complex, and adheres to the surface of the aluminum plate, thereby increasing the thickness and hardness of the oxide film. During anodizing, the transfer of aluminum ions into the electrolyte is hindered, causing them to accumulate on the aluminum plate surface. Electrostatic attraction of anions from the electrolyte further enhances the conductivity at the interface, reducing the reaction resistance and lowering the voltage required for anodizing. This contributes to increased hardness and thickness of the oxide film, reduced porosity, and improved film quality. Furthermore, it reduces heat release, mitigating the effects of Joule heating on the oxide film. This allows the anodizing process to be performed under a wider temperature range and higher current density. Simultaneously, the regulating effect of anions on the current suppresses the excessive generation of oxygen upon temperature increase, reducing its erosive effect on the oxide film. (3) Rare earth elements (cerium sulfate) are also added to the electrolyte, which ionizes more anions, reduces the resistance of the electrolyte, improves the efficiency of ion current, and thickens the barrier layer of the oxide film; it can also promote the generation of water from excess O2- in the system, reduce the production of oxygen, and utilize the surface activity of polymethyl methacrylate to reduce interfacial tension, promote the overflow of oxygen, further reduce the number and size of pores in the oxide film, improve the thickness and density of the oxide film, and improve the corrosion resistance and surface hardness of the finished aluminum plate.

[0023] Furthermore, the S2. sealing process includes the following steps:

[0024] The aluminum plate obtained in step S1 (hereinafter referred to as aluminum plate S1) is placed in a sealing liquid at 65-80℃, sealed, and treated under a negative pressure of 0.1Mpa for 20-30 minutes.

[0025] The sealing solution comprises the following components by weight: 1.62–2.63 g / L nickel acetate, 5–10 g / L accelerator 2-hydroxytriethylamine, 1–2 g / L complexing agent sodium lactate, 0.1–0.5 g / L passivating agent hydrogen peroxide, and 0.5–1.0 g / L ash suppressant polyethylene glycol (PEG). The pH of the system is adjusted to 5.5–6.3 using dilute acetic acid.

[0026] In the above technical solution, the sealing process includes hydrolysis and hydration. Acetate is a weak acid conjugate acid, which readily hydrolyzes, making the solution weakly alkaline. This causes nickel ions to precipitate as hydroxide, which is deposited together with hydrated alumina to achieve sealing. The negative pressure process improves the deposition efficiency of both processes, enhancing the quality of the resulting sealing layer. This results in a denser structure, fewer surface defects, and better protection against corrosive media, giving the S2 aluminum plate superior corrosion resistance.

[0027] Furthermore, the S3. sealing process includes the following steps:

[0028] The aluminum plate obtained in step S2 (hereinafter referred to as aluminum plate S2) is placed in a sealing liquid at 15-35℃ and immersed for 10-30 seconds; then it is taken out, blown dry, and placed at 70-90℃ to dry for 25-35 minutes.

[0029] The sealing solution comprises the following components by weight: 85–112 g / L silica sol, 85–113 g / L aqueous polysiloxane, 129–170 g / L aqueous polyurethane, 1–5 g / L graphene oxide, and has a pH of 8.5–9.5.

[0030] Graphene oxide: particle size 0.5-1.0 mm, thickness 0.8-1.2 nm, sourced from Shanghai Naio Nanotechnology Co., Ltd.

[0031] Polymethyl methacrylate: molecular weight 10,000, sourced from Taicang Kaida Plastic Raw Materials Co., Ltd.;

[0032] Polyethylene glycol: PEG1000, sourced from Haian Petrochemical Plant, Jiangsu Province;

[0033] Silica sol: Nano silica sol, in which the silica particles have a diameter of 20-50 nm, sourced from Guangdong Huierte Nanotechnology Co., Ltd.;

[0034] Waterborne polysiloxane: SJ-230A, sourced from Zongyang Sanjin Pigment Co., Ltd.;

[0035] Furthermore, waterborne polyurethane is prepared by the following process:

[0036] (1) Preparation of pentaerythritol trienoic acid ester:

[0037] Take pentaerythritol, pyridine carboxylic acid, and toluene, stir and mix for 8-15 min, add polymerization inhibitor and catalyst in sequence, heat to 115-125℃, and reflux for 3.8-4.5 h; filter, wash the filtrate with 5% sodium hydroxide solution, neutralize to pH neutral, wash the organic phase with water, and distill under reduced pressure to obtain pentaerythritol trienoate.

[0038] (2) Synthesis of waterborne polyurethane:

[0039] In a nitrogen atmosphere, tetrafluorobutylene glycol and polytetrahydrofuran ether glycol were mixed, and isophorone diisocyanate and dimethylolpropionic acid were added. N,N-dimethylacetamide solvent and dibutyltin dilaurate catalyst were added, and the mixture was reacted at a constant temperature of 70-80℃ for 100-150 min.

[0040] Cool to 50–60°C, add pentaerythritol trienoate and hydroxyethyl methacrylate, and react for 55–65 min; cool to 30–37°C, add (3-mercaptopropyl)triethoxysilane, and react for 150–200 min; add triethylamine to neutralize; add deionized water and stir vigorously for 35–45 min.

[0041] Acetone can be added to adjust the viscosity of the system during the reaction, and the acetone is removed by vacuum distillation after the reaction.

[0042] Furthermore, the molar ratio of pentaerythritol, pyridine carboxylic acid, polymerization inhibitor, and catalyst is 1:(3.0~3.1):(0.03~0.08):(1~5);

[0043] The pyridine carboxylic acid is one or a mixture of two of pyridine 5-vinylcarboxylate and 3-ethylene-1H-pyrrolo[2,3-B]pyridine-2-carboxylic acid, wherein the molar ratio of the mixture is 1:(0.5~2.0);

[0044] The polymerization inhibitor is 1,4-hydroquinone;

[0045] The catalysts are EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) and DMAP (4-dimethylpyridine) in a mass ratio of 2:1.

[0046] Furthermore, the waterborne polyurethane has a solid content of 30% and includes the following components by weight: 2.0 parts tetrafluorobutanediol, 40 parts polytetrahydrofuran ether diol, 25 parts isophorone diisocyanate, 4.5 parts dimethylolpropionic acid, 0.6 to 3.3 parts pentaerythritol trimenoate, 0.9 to 3.9 parts hydroxyethyl methacrylate, and 6.53 parts (3-mercaptopropyl)triethoxysilane.

[0047] In the above technical solution, graphene oxide, with its ultra-high specific surface area, is added as a filler to the sealing liquid system. This effectively blocks the penetration of corrosive media into the aluminum plate S2 within the sealed layer, delaying its corrosion. Furthermore, the presence of zinc oxide in the graphene oxide provides secondary passivation to the oxide film in the aluminum plate S2, maintaining its integrity and protective properties. The nano-silica surface of the silica sol and the molecular chains of waterborne polysiloxanes and waterborne polyurethanes all contain hydroxyl groups, which can react with the surface hydroxyl groups in the graphene oxide to undergo dehydration condensation, increasing the crosslinking degree of the sealed layer, improving its strength and shielding ability, and enhancing its water resistance and corrosion resistance. The water-based nature of the sealing liquid provides excellent permeability and wettability, enabling it to cover and repair surface defects in the aluminum plate S1, improving the wear resistance and scratch resistance of the manufactured curtain wall aluminum panel, and ensuring and enhancing its corrosion resistance.

[0048] In a sealing liquid system, polytetrahydrofuran ether diol reacts with isophorone diisocyanate, introducing chain extenders tetrafluorobutylene glycol and dimethylolpropionic acid, followed by grafting with pentaerythritol trimenoate and hydroxyethyl methacrylate, and end-capping with (3-mercaptopropyl)triethoxysilane to obtain waterborne polyurethane. Pentaerythritol trimenoate is obtained by esterification of pentaerythritol with pyridine-containing carboxylic acids (pyridine 5-vinylcarboxylate, 3-ethylene-1H-pyrrolo[2,3-B]pyridine-2-carboxylic acid). In the waterborne polyurethane system, the introduction of tetrafluorobutylene glycol and pentaerythritol trimenoate into the reaction backbone of polytetrahydrofuran ether diol and isophorone diisocyanate improves the heat resistance and slip properties of the sealing layer, the adhesion strength with aluminum plate S2, and increases the crosslinking density of the sealing liquid system, thereby further improving the mechanical properties, water resistance, and corrosion resistance of the prepared sealing layer.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] 1. The high-hardness corrosion-resistant aluminum curtain wall panel and its preparation method of the present invention use sulfuric acid, boric acid, cerium sulfate and polymethyl methacrylate as electrolyte components for anodizing. Sulfuric acid and boric acid form a mixed acid system, which reduces the solubility of sulfuric acid in the oxide film. Polymethyl methacrylate preferentially adsorbs onto the surface defects of the aluminum panel, alleviating corrosion at the defects and causing aluminum ions to accumulate on the surface of the aluminum panel. This attracts anions in the electrolyte, reduces the reaction resistance, and inhibits the large-scale generation of oxygen, thereby generating a high-thickness oxide film on the surface of the aluminum panel. It also improves the uniformity and density of the oxide film produced by anodizing, effectively improving the corrosion resistance, wear resistance and microhardness of the oxide film, resulting in a curtain wall aluminum panel with better hardness and corrosion resistance.

[0051] 2. The high-hardness corrosion-resistant aluminum curtain wall panel and its preparation method of the present invention improve the deposition efficiency of nickel hydroxide and hydrated aluminum oxide in the sealing process by using negative pressure, thereby improving the quality of the sealing layer, resulting in a dense structure, fewer surface defects, better blocking effect against the intrusion of corrosive media, and superior corrosion resistance of the aluminum curtain wall panel.

[0052] 3. The high-hardness corrosion-resistant aluminum curtain wall panel and its preparation method of the present invention involve reacting polytetrahydrofuran ether diol with isophorone diisocyanate, introducing chain extenders tetrafluorobutylene glycol and dimethylolpropionic acid, grafting with pentaerythritol trienoate and hydroxyethyl methacrylate, and end-capping with 3-mercaptopropyltriethoxysilane. The resulting waterborne polyurethane is mixed with silica sol, waterborne polysiloxane, waterborne polyurethane, and graphene oxide as a sealing liquid system. Dehydration condensation occurs between silanol groups, increasing the crosslinking degree of the prepared sealing layer, improving its strength and shielding ability, and enhancing the mechanical properties, water resistance, and corrosion resistance of the sealing layer. The resulting aluminum curtain wall panel exhibits excellent corrosion resistance. Detailed Implementation

[0053] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0054] The aluminum plate is 7075 aluminum plate, containing the following mass fraction composition: Zn: 5.36%, Mg: 2.43%, Cu: 1.78%, Cr: 0.183%, Ni: 0.81%, Si < 0.05%, Fe < 0.07%, Mn < 0.25%, Ti < 0.06%; the total of other impurities is ≤ 0.15%, the individual impurity is ≤ 0.05%, and the balance is Al.

[0055] Before use, it undergoes pretreatment, the specific process being:

[0056] (1) Heat treatment:

[0057] Solution treatment: Place the aluminum plate in a furnace, heat it to 475℃, hold it for 24 hours, remove it, quench it, and cool it to room temperature;

[0058] Annealing: Heat to 110℃ and hold for 8 hours; heat to 150℃ and hold for 8 hours, then remove and air cool.

[0059] (2) Pretreatment:

[0060] Sand with 800#, 1200#, and 2000# sandpaper in sequence, remove oil with acetone for 30-50 seconds, and then rinse with water;

[0061] Alkaline washing: Immerse in a mixed solution of sodium hydroxide and sodium carbonate at 65°C for 3 minutes; wash with water; the mass concentration of sodium hydroxide in the mixed solution is 38 g / L and the mass concentration of sodium carbonate is 18 g / L.

[0062] Pickling: Immerse in nitric acid solution for 40 seconds; wash with water; dry with nitrogen; the mass concentration of nitric acid solution is 15%.

[0063] Graphene oxide: particle size 0.5-1.0 mm, thickness 0.8-1.2 nm, sourced from Shanghai Naio Nanotechnology Co., Ltd.

[0064] Polymethyl methacrylate: molecular weight 10,000, sourced from Taicang Kaida Plastic Raw Materials Co., Ltd.;

[0065] Polyethylene glycol: PEG1000, sourced from Haian Petrochemical Plant, Jiangsu Province;

[0066] Silica sol: Nano silica sol, in which the silica particles have a diameter of 20-50 nm, sourced from Guangdong Huierte Nanotechnology Co., Ltd.;

[0067] Waterborne polysiloxane: SJ-230A, sourced from Zongyang Sanjin Pigment Co., Ltd.

[0068] Example 1

[0069] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 15℃, with a current density of 1A / dm³. 2 Under the conditions, oxidize for 18 min;

[0070] The electrolyte comprises the following components by weight: 160 g / L sulfuric acid, 5 g / L boric acid, 30 g / L cerium sulfate, and 3 g / L polymethyl methacrylate;

[0071] S2. Sealing treatment: Place the aluminum plate obtained in step S1 into a sealing liquid at 65℃, seal it, and treat it under a negative pressure of 0.1Mpa for 20 minutes;

[0072] The sealing solution comprises the following components by weight: 1.62 g / L nickel acetate, 5 g / L accelerator 2-hydroxytriethylamine, 1 g / L complexing agent sodium lactate, 0.1 g / L passivating agent hydrogen peroxide, and 0.5 g / L ash suppressant polyethylene glycol PEG. The pH of the system is adjusted to 6.3 using dilute acetic acid.

[0073] S3. Sealing treatment:

[0074] (1) Preparation of pentaerythritol trienoic acid ester:

[0075] Take 13.6 g pentaerythritol, 48.6 g pyridine carboxylic acid, and 50 mL toluene, stir and mix for 8 min, then add 0.33 g polymerization inhibitor 1,4-hydroquinone and 1.07 g catalyst DMAP sequentially, heat to 115 °C, and reflux for 3.8 h; filter, wash the filtrate with 5% sodium hydroxide solution, neutralize to pH neutral, wash the organic phase with water, and distill under reduced pressure to obtain pentaerythritol trienoic acid ester; the pyridine carboxylic acid is a mixture of pyridine 5-vinylcarboxylate 149 and 3-ethylene-1H-pyrrolo[2,3-B]pyridine-2-carboxylic acid 188 in a molar ratio of 1:0.5;

[0076] (2) Synthesis of waterborne polyurethane:

[0077] In a nitrogen atmosphere, 2.0 g of tetrafluorobutylene glycol and 40 g of polytetrahydrofuran ether glycol were mixed, 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added, along with 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate. The mixture was kept at 70 °C for 100 min.

[0078] Cool to 50℃, add 0.6g pentaerythritol trimenoate and 3.9g hydroxyethyl methacrylate, and react for 55min; cool to 30℃, add 6.53g (3-mercaptopropyl)triethoxysilane, and react for 150min; add triethylamine to neutralize; add deionized water, adjust the solid content of the system to 30%, and stir vigorously for 35min;

[0079] (3) Sealing treatment:

[0080] The aluminum plate obtained in step S2. is placed in a 15°C sealing liquid and immersed for 10 seconds; then removed, dried, and placed at 70°C for 25 minutes.

[0081] The sealing solution comprises the following components by weight: 85 g / L silica sol, 85 g / L aqueous polysiloxane, 129 g / L aqueous polyurethane, 1 g / L graphene oxide, and has a pH of 8.5.

[0082] Example 2

[0083] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 25℃, with a current density of 2A / dm³. 2 Under the conditions, oxidize for 25 minutes;

[0084] The electrolyte comprises the following components by weight: 180 g / L sulfuric acid, 7 g / L boric acid, 40 g / L cerium sulfate, and 4 g / L polymethacrylic acid;

[0085] S2. Sealing treatment: Place the aluminum plate obtained in step S1 into a sealing liquid at 72℃, seal it, and treat it under a negative pressure of 0.1Mpa for 25min;

[0086] The sealing solution comprises the following components by weight: 2.13 g / L nickel acetate, 6 g / L accelerator 2-hydroxytriethylamine, 1.5 g / L complexing agent sodium lactate, 0.3 g / L passivating agent hydrogen peroxide, and 0.8 g / L ash suppressant polyethylene glycol PEG. The pH of the system is adjusted to 5.9 using dilute acetic acid.

[0087] S3. Sealing treatment:

[0088] (1) Preparation of pentaerythritol trienoic acid ester:

[0089] Take 13.6 g pentaerythritol, 51.9 g pyridine carboxylic acid, and 50 mL toluene, stir and mix for 10 min, then add 0.33-0.88 g of polymerization inhibitor 1,4-hydroquinone and 1.07-5.35 g of catalyst DMAP sequentially, heat to 120 °C, and reflux for 4 h; filter, wash the filtrate with 5% sodium hydroxide solution, neutralize to pH neutral, wash the organic phase with water, and distill under reduced pressure to obtain pentaerythritol trienoic acid ester;

[0090] The mixture contains pyridine carboxylic acid 149 of 5-vinylcarboxylic acid and 188 of 3-ethylene-1H-pyrrolo[2,3-B]pyridine-2-carboxylic acid in a molar ratio of 1:1.2;

[0091] (2) Synthesis of waterborne polyurethane:

[0092] In a nitrogen atmosphere, 2.0 g of tetrafluorobutylene glycol and 40 g of polytetrahydrofuran ether glycol were mixed, and 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added. 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate were added, and the mixture was reacted at a constant temperature of 75 °C for 120 min.

[0093] Cool to 55℃, add 1.9g pentaerythritol trimenoate and 2.4g hydroxyethyl methacrylate, and react for 60min; cool to 34℃, add 6.53g (3-mercaptopropyl)triethoxysilane, and react for 180min; add triethylamine to neutralize; add deionized water, adjust the solid content of the system to 30%, and stir vigorously for 40min;

[0094] (3) Sealing treatment:

[0095] The aluminum plate obtained in step S2. is placed in a 25°C sealing liquid and immersed for 20 seconds; then removed, dried, and placed at 80°C for 30 minutes.

[0096] The sealing solution comprises the following components by weight: 98 g / L silica sol, 99 g / L aqueous polysiloxane, 150 g / L aqueous polyurethane, 3 g / L graphene oxide, and has a pH of 9.0.

[0097] Example 3

[0098] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 35℃, with a current density of 4A / dm³. 2 Under the conditions, oxidize for 28 minutes;

[0099] The electrolyte comprises the following components by weight: 200 g / L sulfuric acid, 10 g / L boric acid, 50 g / L cerium sulfate, and 5 g / L polymethyl methacrylate;

[0100] S2. Sealing treatment: Place the aluminum plate obtained in step S1 into an 80℃ sealing liquid, seal it, and treat it under a negative pressure of 0.1Mpa for 30 minutes;

[0101] The sealing solution comprises the following components by weight: 2.63 g / L nickel acetate, 10 g / L accelerator 2-hydroxytriethylamine, 2 g / L complexing agent sodium lactate, 0.5 g / L passivating agent hydrogen peroxide, and 1.0 g / L ash suppressant polyethylene glycol PEG. The pH of the system is adjusted to 5.5 using dilute acetic acid.

[0102] S3. Sealing treatment:

[0103] (1) Preparation of pentaerythritol trienoic acid ester:

[0104] Take 13.6 g pentaerythritol, 54.0 g pyridine carboxylic acid, and 50 mL toluene, stir and mix for 15 min, then add 0.88 g polymerization inhibitor 1,4-hydroquinone and 5.35 g catalyst DMAP sequentially, heat to 125 °C, and reflux for 4.5 h; filter, wash the filtrate with 5% sodium hydroxide solution, neutralize to pH neutral, wash the organic phase with water, and distill under reduced pressure to obtain pentaerythritol trienoic acid ester;

[0105] (2) Synthesis of waterborne polyurethane:

[0106] In a nitrogen atmosphere, 2.0 g of tetrafluorobutylene glycol and 40 g of polytetrahydrofuran ether glycol were mixed, 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added, along with 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate. The mixture was kept at 80 °C for 150 min.

[0107] Cool to 60℃, add 3.3g pentaerythritol trimenoate and 0.9g hydroxyethyl methacrylate, and react for 65min; cool to 37℃, add 6.53g (3-mercaptopropyl)triethoxysilane, and react for 200min; add triethylamine to neutralize; add deionized water, adjust the solid content of the system to 30%, and stir vigorously for 35-45min.

[0108] (3) Sealing treatment:

[0109] The aluminum plate obtained in step S2. is placed in a 35°C sealing liquid and immersed for 30 seconds; then removed, dried, and placed at 90°C for 35 minutes.

[0110] The sealing solution comprises the following components by weight: 112 g / L silica sol, 113 g / L aqueous polysiloxane, 170 g / L aqueous polyurethane, 5 g / L graphene oxide, and pH 9.5.

[0111] Comparative Example 1

[0112] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 15℃, with a current density of 1A / dm³. 2 Under the conditions, oxidize for 18 min;

[0113] The electrolyte comprises the following components by weight: 160 g / L sulfuric acid, 5 g / L boric acid, 30 g / L cerium sulfate, and 3 g / L tartaric acid;

[0114] The other steps are the same as in Example 1, and the aluminum curtain wall panel is obtained.

[0115] Comparative Example 2

[0116] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 15℃, with a current density of 1A / dm³. 2 Under the conditions, oxidize for 18 min;

[0117] The electrolyte comprises the following components by weight: 160 g / L sulfuric acid, 5 g / L boric acid, and 3 g / L tartaric acid;

[0118] The other steps are the same as in Example 1, and the aluminum curtain wall panel is obtained.

[0119] Comparative Example 3

[0120] S1. Anodizing: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution, and the electrolyte temperature is 15℃, with a current density of 1A / dm³. 2 Under the conditions, oxidize for 18 min;

[0121] The electrolyte comprises the following components by weight: 160 g / L sulfuric acid and 5 g / L boric acid;

[0122] The other steps are the same as in Example 1, and the aluminum curtain wall panel is obtained.

[0123] Comparative Example 4

[0124] S2. Sealing treatment: Place the aluminum plate obtained in step S1 into a sealing liquid at 65°C and treat for 20 minutes;

[0125] The sealing solution comprises the following components by weight: 1.62 g / L nickel acetate, 5 g / L accelerator 2-hydroxytriethylamine, 1 g / L complexing agent sodium lactate, 0.1 g / L passivating agent hydrogen peroxide, and 0.5 g / L ash suppressant polyethylene glycol PEG. The pH of the system is adjusted to 6.3 using dilute acetic acid.

[0126] The other steps are the same as in Comparative Example 3, and the aluminum curtain wall panel is obtained.

[0127] Comparative Example 5

[0128] (2) Synthesis of waterborne polyurethane:

[0129] In a nitrogen atmosphere, 2.0 g of tetrafluorobutylene glycol and 40 g of polytetrahydrofuran ether glycol were mixed, 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added, along with 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate. The mixture was kept at 70 °C for 100 min.

[0130] Cool to 50℃, add 0.6g pentaerythritol triacrylate and 3.9g hydroxyethyl methacrylate, and react for 55min; cool to 30℃, add 6.53g (3-mercaptopropyl)triethoxysilane, and react for 150min; add triethylamine to neutralize; add deionized water, adjust the solid content of the system to 30%, and stir vigorously for 35min;

[0131] (3) Sealing treatment:

[0132] The aluminum plate obtained in step S2. is placed in a 15°C sealing liquid and immersed for 10 seconds; then removed, dried, and placed at 70°C for 25 minutes.

[0133] The sealing solution comprises the following components by weight: 85 g / L silica sol, 85 g / L aqueous polysiloxane, 129 g / L aqueous polyurethane, 1 g / L graphene oxide, and has a pH of 8.5.

[0134] The other steps are the same as in Comparative Example 4, and the aluminum curtain wall panel is obtained.

[0135] Comparative Example 6

[0136] (2) Synthesis of waterborne polyurethane:

[0137] In a nitrogen atmosphere, 2.0 g of 1,4-butanediol and 40 g of polytetrahydrofuran ether diol were mixed, 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added, along with 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate. The mixture was kept at 70 °C for 100 min.

[0138] Cool to 50℃, add 4.4g of hydroxyethyl methacrylate, and react for 55min; cool to 30℃, add 6.53g of (3-mercaptopropyl)triethoxysilane, and react for 150min; add triethylamine to neutralize; add deionized water, adjust the solid content of the system to 30%, and stir vigorously for 35min.

[0139] (3) Sealing treatment:

[0140] The aluminum plate obtained in step S2. is placed in a 15°C sealing liquid and immersed for 10 seconds; then removed, dried, and placed at 70°C for 25 minutes.

[0141] The sealing solution comprises the following components by weight: 85 g / L silica sol, 85 g / L aqueous polysiloxane, 129 g / L aqueous polyurethane, 1 g / L graphene oxide, and has a pH of 8.5.

[0142] The other steps are the same as in Comparative Example 4, and the aluminum curtain wall panel is obtained.

[0143] Comparative Example 7

[0144] (2) Synthesis of waterborne polyurethane:

[0145] In a nitrogen atmosphere, 2.0 g of 1,4-butanediol and 40 g of polytetrahydrofuran ether diol were mixed, 25 g of isophorone diisocyanate and 4.5 g of dimethylolpropionic acid were added, along with 300 mL of solvent N,N-dimethylacetamide and 0.2 g of catalyst dibutyltin dilaurate. The mixture was kept at 70 °C for 100 min.

[0146] Add triethylamine to neutralize; add deionized water to adjust the solid content of the system to 30%, and stir vigorously for 35 minutes;

[0147] (3) Sealing treatment:

[0148] The aluminum plate obtained in step S2. is placed in a 15°C sealing liquid and immersed for 10 seconds; then removed, dried, and placed at 70°C for 25 minutes.

[0149] The sealing solution comprises the following components by weight: 85 g / L silica sol, 85 g / L aqueous polysiloxane, 129 g / L aqueous polyurethane, with a pH of 8.5.

[0150] The other steps are the same as in Comparative Example 4, and the aluminum curtain wall panel is obtained.

[0151] The above process is a small-scale laboratory test and can be scaled up proportionally.

[0152] experiment

[0153] The aluminum curtain wall panels obtained in Examples 1-3 and Comparative Examples 1-7 were used to prepare samples, and their performance was tested and the test results were recorded:

[0154] The thickness of the oxide film in the sample was detected using a digital eddy current thickness gauge.

[0155] The hardness of the oxide film in the sample was tested using a Vickers hardness tester under a load of 0.98 N, and the load was unloaded after 15 seconds.

[0156] A film thickness profiler was used to detect the roughness of the oxide film in the sample by moving a probe on the surface of the oxide film in the sample.

[0157] Using a platinum electrode as the auxiliary electrode, a saturated calomel electrode as the reference electrode, and a 3.5% sodium chloride solution as the corrosion medium, an electrochemical workstation was used to test the polarization curve of the oxide film in the sample. The scan rate was 1 mV / s, and the corrosion current density of the oxide film in the sample was obtained by Tafel extrapolation.

[0158] Table 1:

[0159] Oxide film Thickness (μm) Hardness (HV) Roughness (μm) <![CDATA[Corrosion current density (μA / cm 2 )]]> Example 1 34.3 412.6 0.516 <![CDATA[6.14×10 -3 ]]> Example 2 37.9 446.2 0.472 <![CDATA[3.86×10 -3 ]]> Example 3 41.4 407.0 0.621 <![CDATA[1.77×10 -3 ]]> Comparative Example 1 30.1 387.5 0.667 <![CDATA[9.44×10 -3 ]]> Comparative Example 2 28.5 351.6 0.929 <![CDATA[3.67×10 -2 ]]> Comparative Example 3 27.4 330.4 1.257 <![CDATA[8.94×10 -2 ]]>

[0160] The roughness of aluminum plate S2 was detected by moving a probe across the oxide film surface of the sample using a film thickness profiler.

[0161] Using GB / T 19746-2018 as the reference standard, the samples were placed in a salt spray environment with a test water temperature of 28℃, an exposure temperature of 70℃, a relative humidity of 80%RH, an immersion time of 10 min, and an exposure time of 50 min. The corrosion solution consisted of 2.45% NaCl + 0.52% MgCl2 + 0.12% CaCl2 + 0.41% Na2SO4, and the pH was adjusted to 8 with NaOH solution. The corrosion cycle was 32 days.

[0162] Table 2:

[0163] Aluminum plate S2 Roughness before corrosion (μm) Roughness (μm) after 32 days of corrosion <![CDATA[Corrosion 32d weight loss rate (mg / cm 2 )]]> Example 1 0.413 1.024 1.17 Example 2 0.397 0.983 1.02 Example 3 0.454 1.011 1.06 Comparative Example 1 0.589 1.075 1.21 Comparative Example 2 0.743 1.126 1.26 Comparative Example 3 0.769 1.152 1.32 Comparative Example 4 0.821 1.247 1.43

[0164] The mechanical properties of the sealing layer in the specimen were tested using a universal testing machine. The sealing layer specimen was dumbbell-shaped with a diameter of 30 mm × 4 mm and a tensile rate of 50 mm / min.

[0165] The adhesion of the sealing layer of the sample was tested using the cross-cut adhesion test method with GB / T 9286 as the reference standard.

[0166] Using GB / T 1736 as a reference standard, the sample was placed in a 5.0 wt% NaCl solution, and the time for the sealing layer to bubble and the time for the sample to rust were recorded as the corrosion time.

[0167] Table 3:

[0168]

[0169]

[0170] Based on the data in the table above, the following conclusions can be clearly drawn:

[0171] The aluminum curtain wall panels obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-7. The test results show that...

[0172] Compared with the comparative examples, the aluminum curtain wall panels obtained in Examples 1-3 have a longer corrosion resistance time; the oxide film has better hardness, roughness, thickness and corrosion current density data; aluminum plate S2 has lower roughness before corrosion, roughness after 32 days of corrosion and weight loss rate after 32 days of corrosion; the sealing layer has better mechanical properties and adhesion data; this fully demonstrates that the present invention has achieved improved corrosion resistance of the prepared aluminum curtain wall panels and has higher hardness.

[0173] Compared with Example 1, in Comparative Example 1, the polyacrylic acid in the electrolyte was replaced with an equal mass of tartaric acid; in Comparative Example 2, the polyacrylic acid in the electrolyte was replaced with an equal mass of tartaric acid, and the component cerium sulfate was removed; in Comparative Example 3, the components polyacrylic acid and cerium sulfate were removed from the electrolyte. Under acidic conditions, the hydroxyl and carboxyl groups of tartaric acid are difficult to dissociate to form oxygen anions, and their complexing ability for aluminum ions is very weak. The lack of rare earth ions leads to the deterioration of the thickness and roughness of the oxide film, as well as the hardness and corrosion current density of the aluminum plate S1.

[0174] Compared with Comparative Example 3, the sealing process of Comparative Example 4 eliminated the negative pressure process; the surface roughness data of aluminum plate S2 increased and the corrosion resistance decreased.

[0175] Compared with Comparative Example 4, the sealing treatment of Comparative Example 5 replaced pentaerythritol trimenoate with pentaerythritol triacrylate; the sealing treatment of Comparative Example 6 removed the pentaerythritol trimenoate component and replaced tetrafluorobutanediol with 1,4-butanediol; in the sealing treatment process of Comparative Example 7, the waterborne polyurethane was prepared from 1,4-butanediol, polytetrahydrofuran ether diol, isophorone diisocyanate, and dimethylolpropionic acid; the mechanical properties and adhesion data of the sealing layer decreased, and the corrosion resistance time of the sample in salt water became shorter.

[0176] In summary, the settings of the anodizing, sealing, and closure processes and the components used in this application can improve the corrosion resistance of the manufactured aluminum curtain wall panels.

[0177] 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.

[0178] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel, characterized in that: Including the following processes: S1. Anodizing: An aluminum plate is used as the anode and pure aluminum as the cathode, and the plates are placed in an electrolyte to perform anodizing. The electrolyte includes sulfuric acid, boric acid, cerium sulfate, and polymethyl methacrylate. S2. Sealing treatment: The aluminum plate obtained in step S1 is placed in a sealing liquid and sealed under negative pressure. The sealing liquid includes nickel acetate, accelerator, complexing agent, passivating agent and dust suppressant. S3. Sealing treatment: The aluminum plate obtained in step S2 is placed in a sealing liquid, dipped, and dried to obtain a curtain wall aluminum plate; the sealing liquid includes silica sol, waterborne polysiloxane, waterborne polyurethane and graphene oxide; The waterborne polyurethane is prepared by the following process: (1) Preparation of pentaerythritol trienoic acid ester: Take pentaerythritol, pyridine carboxylic acid, and toluene, stir and mix for 8-15 min, then add polymerization inhibitor and catalyst in sequence, heat to 115-125℃, and reflux for 3.8-4.5 h to obtain pentaerythritol trienoic acid ester; (2) Synthesis of waterborne polyurethane: In a nitrogen atmosphere, tetrafluorobutylene glycol and polytetrahydrofuran ether glycol were mixed, and isophorone diisocyanate and dimethylolpropionic acid were added. Solvent and catalyst were added, and the mixture was reacted at a constant temperature of 70-80°C for 100-150 min. Cool to 50–60°C, add pentaerythritol trienoate and hydroxyethyl methacrylate, and react for 55–65 min; cool to 30–37°C, add (3-mercaptopropyl)triethoxysilane, and react for 150–200 min; add triethylamine to neutralize; add deionized water and stir vigorously for 35–45 min. The pyridine carboxylic acid is one or a mixture of two of pyridine 5-vinylcarboxylate and 3-ethylene-1H-pyrrolo[2,3-B]pyridine-2-carboxylic acid, with a molar ratio of 1:(0.5 to 2.0).

2. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 1, characterized in that: The S1. anodizing process includes the following steps: An aluminum plate is used as the anode, and pure aluminum is used as the cathode. The plates are placed in an electrolyte solution at a temperature of 15–35°C and a current density of 1–4 A / dm³. 2 Under these conditions, oxidize for 18–28 minutes.

3. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 2, characterized in that: The electrolyte comprises the following components by weight: 160–200 g / L sulfuric acid, 5–10 g / L boric acid, 30–50 g / L cerium sulfate, and 3–5 g / L polymethyl methacrylate.

4. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 1, characterized in that: The S2 sealing process includes the following steps: The aluminum plate obtained in step S1 is placed in a sealing liquid at 65-80℃, sealed, and treated under a negative pressure of 0.1 MPa for 20-30 minutes.

5. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 4, characterized in that: The sealing solution comprises the following components by weight: 1.62–2.63 g / L nickel acetate, 5–10 g / L accelerator 2-hydroxytriethylamine, 1–2 g / L complexing agent sodium lactate, 0.1–0.5 g / L passivating agent hydrogen peroxide, and 0.5–1.0 g / L ash suppressant polyethylene glycol (PEG). The pH of the system is adjusted to 5.5–6.3 using dilute acetic acid.

6. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 1, characterized in that: The S3 sealing process includes the following steps: The aluminum plate obtained in step S2 is placed in a sealing liquid at 15-35℃ and immersed for 10-30 seconds; then removed, dried, and placed at 70-90℃ for 25-35 minutes.

7. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 6, characterized in that: The sealing liquid comprises the following components by weight: 85–112 g / L silica sol, 85–113 g / L aqueous polysiloxane, 129–170 g / L aqueous polyurethane, 1–5 g / L graphene oxide, and has a pH of 8.5–9.

5.

8. The method for preparing a high-hardness, corrosion-resistant aluminum curtain wall panel according to claim 1, characterized in that: The aluminum plate is a 7075 aluminum plate with the following mass fraction composition: Zn: 5.3-5.6%, Mg: 2.1-2.9%, Cu: 1.50-2.0%, Cr: 0.18-0.23%, Ni: 0.5-1.0%, Si < 0.05%, Fe < 0.07%, Mn < 0.25%, Ti < 0.06%; the total of other impurities is ≤ 0.15%, the individual impurity is ≤ 0.05%, and the balance is Al.

9. A high-hardness corrosion-resistant aluminum curtain wall panel prepared by the method of any one of claims 1-8.

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