A high-brightness aluminum alloy sealing agent and its sealing process

Abstract

This invention discloses a high-gloss aluminum alloy sealing agent and its sealing process. The high-gloss aluminum alloy sealing agent comprises, by weight, 100-120 parts of an ethylene-acrylic acid emulsion with a grafting rate of 18-22; 25-35 parts of filler; 10-15 parts of diluent; 2-4 parts of film-forming aid; and 10-20 parts of deionized water. The high-gloss aluminum alloy sealing agent not only improves the corrosion resistance of the aluminum alloy, but also, to meet decorative aesthetic requirements, the sealed surface of the aluminum alloy possesses a high-gloss finish, resulting in a smooth and textured surface.

Description

Technical Field

[0001] This invention relates to the field of aluminum profile surface treatment technology, and in particular to a high-brightness aluminum alloy sealing agent and its sealing process. Background Technology

[0002] Aluminum profiles, due to their excellent thermal ductility and ease of processing, are widely used in emerging fields such as aerospace, construction, and solar energy. When heat-treated aluminum profiles are placed in air, a dense aluminum oxide film forms on their surface with oxygen, providing a certain degree of corrosion resistance. However, because the protective layer formed in the natural environment is too thin and its corrosion resistance is insufficient, it cannot meet the corrosion resistance requirements of some aluminum alloys that need to be used in long-term high-temperature, high-salinity environments. Therefore, surface treatment of aluminum alloys is necessary to improve their corrosion resistance. Anodizing is a method that uses an acidic electrolyte such as sulfuric acid as the anode, a platinum or lead plate as the cathode, and applies direct current, causing a protective film to form on the surface of the aluminum alloy anode, thus providing corrosion resistance.

[0003] After anodizing, aluminum alloy profiles have a thin film of 1-20 μm thickness, composed of aluminum oxide, aluminum sulfate, etc., forming on their surface. Without electrophoresis, the porous structure of this film makes the aluminum alloy susceptible to corrosion. In this case, a sealing process can be performed, using an organic coating to seal the loose pores. Sealing, unlike electrophoresis, does not require an electric current, allowing the organic material to directly penetrate the oxide film's pores. Therefore, the composition of the organic material used for sealing differs from that used in electrophoresis.

[0004] Existing sealing agents often use numerous additives, have poor corrosion resistance, require multiple sealing cycles, and lack a high-gloss finish. Previously, inorganic nickel acetate was used as a sealing agent, which was simpler and more convenient than using organic agents. However, for aluminum alloys requiring high surface properties, inorganic sealing cannot meet the requirements for high corrosion resistance. Using organic agents for sealing significantly improves the salt spray resistance of aluminum alloys. Summary of the Invention

[0005] The purpose of this invention is to provide an aluminum alloy sealing agent and its sealing process, which not only improves the corrosion resistance of aluminum alloy, but also, in order to meet the decorative appearance requirements, gives the aluminum alloy surface a high gloss, smooth surface, and texture.

[0006] To achieve the above objectives, the present invention provides a high-brightness aluminum alloy sealing agent, characterized in that it comprises the following raw materials by weight: 100-120 parts of ethylene-acrylic acid emulsion with a grafting rate of 18-22; 25-35 parts of filler; 10-15 parts of diluent; 2-4 parts of film-forming aid; and 10-20 parts of deionized water.

[0007] Furthermore, by weight, it contains the following raw materials: 100-115 parts of ethylene-acrylic acid emulsion with a grafting rate of 18-22; 25-35 parts of filler; 10-15 parts of diluent; 2-4 parts of film-forming aid; and 10-20 parts of deionized water.

[0008] Furthermore, the preparation method of the ethylene-acrylic acid emulsion includes the following steps:

[0009] Step 1: Add 40-50 parts of polyethylene wax to 80-100 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.5-1 parts of surfactant and 0.5-0.8 parts of initiator to maintain the temperature at 50-80℃.

[0010] Step 2: Slowly add 15 parts of acrylic monomer, and the solution will change from colorless and transparent to slightly milky white;

[0011] Step 3: After the addition is complete, add 1-2 parts buffer, 1-2 parts stabilizer, 0.5-1 part ammonia, and then add an appropriate amount of 45-55% NaOH to adjust the pH to 7-8, thus obtaining a semi-transparent white ethylene acrylic emulsion.

[0012] Furthermore, the molecular weight of the polyethylene wax is 800-1000;

[0013] Optionally, the surfactant is either sodium dodecyl sulfate or sodium dodecyl sulfonate.

[0014] Optionally, the initiator is any one of potassium persulfate, ammonium persulfate, and sodium persulfate.

[0015] Optionally, the buffer is any one of sodium bicarbonate, potassium dihydrogen phosphate, and sodium acetate.

[0016] Optionally, the stabilizer is polyvinyl alcohol;

[0017] Optional, in step two, the acrylic monomer is added dropwise over 20 minutes.

[0018] Furthermore, the filler is a mixture of equal masses of titanium dioxide and basic magnesium carbonate; the diluent is ethanol; and the film-forming aid is propylene glycol ethyl ether or propylene glycol butyl ether.

[0019] Furthermore, the preparation method involves dissolving polyethylene acrylic acid in deionized water; then adding a film-forming aid and stirring until homogeneous; and finally adding a diluent and a filler.

[0020] The present invention also provides a high-brightness aluminum alloy sealing process, characterized in that the high-brightness aluminum alloy sealing agent is used.

[0021] Furthermore, the following steps are included:

[0022] S1 Hanging Material: Grind off the oxide film on the edges of the hanging rod to expose the white area. If there is dead paint attached to the hanging rod, remove the dead paint. Check whether the quality of the aluminum alloy substrate meets the requirements, and fix the substrate that meets the requirements to the hanging rod.

[0023] S2 Low-Temperature Polishing: The substrate is immersed in a sulfuric acid aqueous solution;

[0024] S3 First water wash: The substrate is rinsed with an acidic aqueous solution;

[0025] S4 Alkaline Etching: The substrate is immersed in an aqueous sodium hydroxide solution;

[0026] S5 Secondary water wash, in which the substrate is rinsed with an acidic aqueous solution;

[0027] S6 neutralization, the substrate is soaked in sulfuric acid aqueous solution;

[0028] S7 involves three water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0029] S8 oxidation, using an aqueous sulfuric acid solution for anodic oxidation.

[0030] S9 involves four water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0031] S10 sealing is performed using any of the high-brightness aluminum alloy sealing agents described in claims 1-6;

[0032] S11 involves five water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0033] S12 drain.

[0034] Furthermore, in the S2 polishing process, the concentration of the sulfuric acid aqueous solution is 140-190 g / L, and the immersion time is 1-5 min;

[0035] Optionally, the first wash, the second wash, the third wash, the fourth wash, and the fifth wash are each independently rinsed with deionized water at pH 2-3.

[0036] Preferably, in the S4 alkaline etching process, the concentration of the sodium hydroxide aqueous solution is 50-80 g / L, and the Al concentration in the solution is controlled. 3+ <120g / L, solution temperature 45-60℃, soaking time 30s-15min;

[0037] Optionally, in the S6 neutralization step, the concentration of the sulfuric acid aqueous solution is 140-250 g / L, and the soaking time is 2-5 min;

[0038] Optionally, in S8 anodizing, the concentration of the sulfuric acid aqueous solution is 140-190 g / L, the solution temperature is controlled at 18-22℃, the voltage is 15-18V, and the current is 100-150 A / m. 2 The energizing time is 20-37 minutes, and an oxide film with a thickness of 1-20 μm is formed on the surface of the substrate;

[0039] Optionally, in the S10 sealing process, the groove contains the high-brightness aluminum alloy sealing agent, and the temperature is 45-65℃;

[0040] Optionally, S12 dewatering uses an acidic solution with pH = 4-6.

[0041] The ethylene-acrylic emulsion used in this invention introduces short-chain polyethylene wax during the polymerization of acrylic monomers via solution grafting, providing ethylene chains. The addition of ethylene chains increases the functionality of the acrylic resin. The coating formulated from the polymerized ethylene-acrylic emulsion has the advantages of acid and alkali resistance and corrosion resistance, and can be used as an anti-corrosion coating for metals. After use, the neutral salt spray resistance of the metal reaches 1500h.

[0042] In the preparation process of ethylene-acrylic acid emulsion, polyethylene wax emulsifies and reacts directly with acrylic acid monomers in water to generate ethylene-acrylic acid emulsion, with a high grafting rate (18-22%); the reaction can be carried out without sealing conditions and pressure, and the equipment requirements are low; and there is no need to introduce ethylene gas, so the process is simple and safe.

[0043] The high-brightness aluminum alloy sealing agent of this invention does not require the addition of other additives. The high-brightness aluminum alloy prepared according to the high-brightness aluminum alloy sealing process of this invention has a high-brightness effect, and the hardness of the coating film is 4H-5H, as determined according to GB / T 6739-1996; the adhesion grade of the coating film is 0-1, as determined according to GB / T 1720-79(89); corrosion resistance: the withstand time is greater than or equal to 1500h under the test temperature of 35±2℃ and the neutral salt spray concentration of 5±1wt%. It significantly improves the corrosion resistance of the material, and the paint film has high adhesion and is not easy to peel off, thus making it more suitable for high-corrosion, high-strength, and high-pressure environments, expanding the application field of aluminum profiles. Attached Figure Description

[0044] Figure 1 This is a diagram showing the effect of the sealing agent obtained in this invention on anodized films. Detailed Implementation

[0045] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0046] The following testing methods are included:

[0047] The method for measuring the grafting rate of acrylic acid involves extracting polyethylene acrylic acid powder with acetone for 20-24 hours, dissolving 0.5g in hot xylene, then neutralizing with sodium hydroxide-ethanol solution, using phenolphthalein as an indicator, and back-tapping excess alkali with hydrochloric acid. Finally, the grafting rate is measured.

[0048] The formula for calculating the grafting rate is as follows:

[0049] (Molar amount of sodium hydroxide - molar amount of hydrochloric acid) * 70.06 / 0.5 * 100%.

[0050] Coating thickness: Measured according to GB 1764-79.

[0051] Hardness of the coating: determined according to GB / T 6739-1996.

[0052] The adhesion of the coating was determined according to GB / T 1720-79(89).

[0053] Salt spray resistance test: Refer to GB / T 10125-2012 and use the neutral salt spray test.

[0054] Acid resistance (accelerated copper sulfate) test: The test shall be conducted in accordance with GB / T 10125-2012.

[0055] Example 1: Preparation of ethylene-acrylic acid emulsion:

[0056] The preparation process of ethylene-acrylic acid emulsion includes the following steps:

[0057] Step 1: Add 40-50 parts of polyethylene wax to 80-100 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.5-1 parts of surfactant and 0.5-0.8 parts of initiator to maintain the temperature at 50-80℃.

[0058] Step 2: Begin slowly adding 15 parts of acrylic monomer, adding the acrylic monomer over 20 minutes; the solution changes from white and transparent to slightly milky white;

[0059] Step 3: After the addition is complete, add 1-2 parts buffer, 1-2 parts stabilizer, 0.5-1 part ammonia, and then add an appropriate amount of 45-55% NaOH to adjust the pH to 7-8, thus obtaining a semi-transparent white ethylene acrylic emulsion.

[0060] In this embodiment, the polyethylene wax has a molecular weight of 800-1000. It was purchased from Rushan Beihua New Material Technology Co., Ltd. A low molecular weight is beneficial for the high grafting rate of acrylic acid and also for emulsification.

[0061] In this embodiment, the surfactant is either sodium dodecyl sulfate or sodium dodecyl sulfonate.

[0062] In this embodiment, the initiator is any one of potassium persulfate, ammonium persulfate, and sodium persulfate. The initiator enables the grafting reaction between polyethylene wax and acrylic monomer.

[0063] In this embodiment, the buffer is any one of sodium bicarbonate, potassium dihydrogen phosphate, and sodium acetate. The buffer is used to regulate the reaction equilibrium.

[0064] In this embodiment, the stabilizer is polyvinyl alcohol.

[0065] The ethylene-acrylic acid emulsion prepared in this embodiment has at least the following beneficial effects:

[0066] 1. In this embodiment, the ethylene-acrylic acid emulsion preparation process involves the direct reaction of polyethylene wax emulsification with acrylic acid monomers in water to generate ethylene-acrylic acid emulsion. The grafting rate is high (18-22), and the reaction can be carried out without pressure, resulting in low equipment requirements. Furthermore, it does not require the introduction of ethylene gas, making the process simple and safe.

[0067] 2. This preparation process uses emulsion polymerization. Because the directly synthesized ethylene-acrylic acid emulsion has high corrosion resistance, it can be used as a metal anti-corrosion coating. When the semi-transparent white ethylene-acrylic acid emulsion is immersed in metal for 3-4 seconds and then dried, a salt spray test is conducted; the time for white and red rust to appear is as long as approximately 1500 hours.

[0068] Multiple experiments were conducted using the ethylene-acrylic acid emulsion preparation process described in this embodiment. The following section selects several experimental groups and control groups to further illustrate the beneficial effects of the ethylene-acrylic acid emulsion preparation process described in this embodiment.

[0069] Experimental Group 1

[0070] Step 1: Add 40 parts of polyethylene wax with a molecular weight of 800-1000 to 80 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.5 parts of surfactant and 0.5 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfate and the initiator is potassium persulfate.

[0071] Step 2: Begin slowly adding 15 parts of acrylic monomer, with the acrylic monomer added over 20 minutes; the solution changes from white and transparent to slightly milky white.

[0072] Step 3: After the addition is complete, add 1 part buffer, 1 part stabilizer, 0.5 parts ammonia, and then add an appropriate amount of 50% NaOH to adjust the pH to 7-8, thus obtaining a translucent white ethylene-acrylic acid emulsion. The buffer is sodium bicarbonate.

[0073] Step 4: Immerse the metal in the ethylene-acrylic emulsion for 3-4 seconds, then dry it and conduct a salt spray test to observe the time it takes for the metal to develop white and red rust.

[0074] Experimental Group 2

[0075] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfate and the initiator is potassium persulfate.

[0076] Step 2: Begin slowly adding 15 parts of acrylic monomer, with the acrylic monomer added over 20 minutes; the solution changes from white and transparent to slightly milky white.

[0077] Step 3: After the addition is complete, add 1.5 parts buffer, 1.5 parts stabilizer, and 0.75 parts ammonia. Then add an appropriate amount of 50% NaOH to adjust the pH to 7-8, thus obtaining a translucent white ethylene-acrylic acid emulsion. The buffer is sodium bicarbonate.

[0078] Step 4: Immerse the metal in the ethylene-acrylic emulsion for 3-4 seconds, then dry it and conduct a salt spray test to observe the time it takes for the metal to develop white and red rust.

[0079] Experimental Group 3

[0080] Step 1: Add 50 parts of polyethylene wax with a molecular weight of 800-1000 to 100 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 1 part of surfactant and 0.8 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfate and the initiator is potassium persulfate.

[0081] Step 2: Begin slowly adding 15 parts of acrylic monomer, with the acrylic monomer added over 20 minutes; the solution changes from white and transparent to slightly milky white.

[0082] Step 3: After the addition is complete, add 2 parts buffer, 2 parts stabilizer, 1 part ammonia, and then add an appropriate amount of 50% NaOH to adjust the pH to 7-8, thus obtaining a translucent white ethylene-acrylic acid emulsion. The buffer is sodium bicarbonate.

[0083] Step 4: Immerse the metal in the ethylene-acrylic emulsion for 3-4 seconds, then dry it and conduct a salt spray test to observe the time it takes for the metal to develop white and red rust.

[0084] Experimental Group 4

[0085] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfonate and the initiator is ammonium persulfate.

[0086] Step 2: Begin slowly adding 15 parts of acrylic monomer, with the acrylic monomer added over 20 minutes; the solution changes from white and transparent to slightly milky white.

[0087] Step 3: After the addition is complete, add 1.5 parts buffer, 1.5 parts stabilizer, and 0.75 parts ammonia. Then add an appropriate amount of 50% NaOH to adjust the pH to 7-8, thus obtaining a translucent white ethylene-acrylic acid emulsion. The buffer is potassium dihydrogen phosphate.

[0088] Step 4: Immerse the metal in the ethylene-acrylic emulsion for 3-4 seconds, then dry it and conduct a salt spray test to observe the time it takes for the metal to develop white and red rust.

[0089] Experimental Group 5

[0090] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and maintain the temperature at 50-80℃; the surfactant is sodium dodecyl sulfonate and the initiator is sodium persulfate.

[0091] Step 2: Begin slowly adding 15 parts of acrylic monomer, with the acrylic monomer added over 20 minutes; the solution changes from white and transparent to slightly milky white.

[0092] Step 3: After the addition is complete, add 1.5 parts buffer, 1.5 parts stabilizer, and 0.75 parts ammonia. Then add an appropriate amount of 50% NaOH to adjust the pH to 7-8, thus obtaining a translucent white ethylene acrylic emulsion. The buffer is sodium acetate.

[0093] Step 4: Immerse the metal in the ethylene-acrylic emulsion for 3-4 seconds, then dry it and conduct a salt spray test to observe the time it takes for the metal to develop white and red rust.

[0094] Comparison Group 1

[0095] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 1000-8000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfonate and the initiator is potassium persulfate.

[0096] Step 2: Slowly add 15 parts of acrylic monomer over 20 minutes; separate the white granular suspension, which is found to be insoluble in water and cannot be tested.

[0097] Comparison Group 2

[0098] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is OP-10 and the initiator is potassium persulfate.

[0099] Step 2: Slowly add 15 parts of acrylic monomer over 20 minutes; separate the white granular suspension, which is found to be insoluble in water and cannot be tested.

[0100] Comparison Group 3

[0101] Step 1: Add 45 parts of polyethylene wax with a molecular weight of 800-1000 to 90 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.75 parts of surfactant and 0.75 parts of perinitiator, and keep the temperature at 50-80℃; the surfactant is sodium dodecyl sulfate and the initiator is potassium persulfate.

[0102] Step 2: Slowly add 15 parts of acrylic monomer over 10 minutes. If the acrylic monomer is added too quickly, it will clump together and form a white, waxy hard solid, preventing the reaction from proceeding.

[0103] Table 1. Comparison of components and experimental phenomena in each experimental group and control group.

[0104]

[0105]

[0106] According to the experimental results in Table 1, the ethylene-acrylic acid emulsion prepared by the process of this invention has the advantages of acid and alkali resistance and corrosion resistance. It can be used as an anti-corrosion coating for metals. After use, the neutral salt spray resistance of the metal reaches 1500h.

[0107] 2. Comparing control groups 1 and 2 with the five experimental groups, it is evident that only low molecular weight polyethylene wax can react with acrylic acid monomers to form ethylene-acrylic acid emulsions, which is beneficial for high grafting rates of acrylic acid and emulsification. Furthermore, there are specific requirements for the choice of surfactant; using OP-10 as an emulsifier cannot dissolve ethylene-acrylic acid in water.

[0108] 3. Compared with the other five experimental groups, it can be seen that acrylic monomer should not be added too quickly, otherwise it will clump together and form a white waxy hard solid, which will prevent the reaction from proceeding.

[0109] Example 2: Preparation of high-brightness aluminum alloy sealing agent

[0110] A high-brightness aluminum alloy sealing agent was prepared using the ethylene-acrylic acid emulsion prepared in Experiment Group 1.

[0111] According to the dosage in Table 2, add the ethylene acrylic emulsion to deionized water at 45-60℃. Maintain the temperature at 45-60℃, add propylene glycol ethyl ether, then add ethanol and titanium dioxide + basic magnesium carbonate (mass ratio 1:1).

[0112] Table 2. Raw material usage (parts by weight) for high-brightness aluminum alloy sealant.

[0113]

[0114] Example 3: Preparation of high-brightness aluminum alloy sealing agent

[0115] The materials are shown in Table 2. The ethylene-acrylic acid emulsion was prepared in Experimental Group 1.

[0116] The preparation method is the same as in Example 2.

[0117] Example 4: Preparation of high-brightness aluminum alloy sealing agent

[0118] The materials are shown in Table 2. The ethylene-acrylic acid emulsion was prepared in Experimental Group 1, with the film-forming aid propylene glycol ethyl ether replaced by propylene glycol butyl ether.

[0119] The preparation method is the same as in Example 2.

[0120] Example 5: Preparation of high-brightness aluminum alloy sealing agent

[0121] The materials are shown in Table 2. The ethylene-acrylic acid emulsion was prepared in Experimental Group 2, with the film-forming aid propylene glycol ethyl ether replaced by propylene glycol butyl ether.

[0122] The preparation method is the same as in Example 2.

[0123] Example 6: Preparation of high-brightness aluminum alloy sealing agent

[0124] The materials are shown in Table 2. The ethylene-acrylic acid emulsion was prepared in Experimental Group 2, with the film-forming aid propylene glycol ethyl ether replaced by propylene glycol butyl ether.

[0125] The preparation method is the same as in Example 2.

[0126] Example 7: Preparation of high-brightness aluminum alloy sealing agent

[0127] The materials are shown in Table 2. The ethylene-acrylic acid emulsion was prepared in Experimental Group 2.

[0128] The preparation method is the same as in Example 2.

[0129] Comparative Example 1:

[0130] The materials are shown in Table 2. Other details are the same as in Example 2.

[0131] The preparation method is the same as in Example 2.

[0132] Comparative Example 2

[0133] Materials are shown in Table 2. Other aspects are the same as in Example 2, except that a commercially available hot alkaline aqueous solution of ethylene-acrylic acid (grafting rate 14%) is used instead of the ethylene-acrylic acid emulsion.

[0134] The preparation method is the same as in Example 2.

[0135] Example 8: High-brightness aluminum alloy sealing process

[0136] S1 Hanging Material: Grind off the oxide film on the edge of the hanging rod to expose the white area. If there is dead paint on the hanging rod, remove the dead paint. Check whether the quality of the aluminum alloy substrate (select AA10 aluminum alloy profile) meets the requirements, and fix the substrate that meets the requirements on the hanging rod.

[0137] S2 polishing: The substrate is immersed in a sulfuric acid aqueous solution; the concentration of the sulfuric acid aqueous solution is 140-190 g / L, and the immersion time is 1-5 min;

[0138] S3 Single water wash: The substrate is rinsed with an acidic aqueous solution (pH=2-3);

[0139] S4 Alkaline Etching: The substrate is immersed in an aqueous sodium hydroxide solution; the concentration of the sodium hydroxide solution is 50-80 g / L, and the alkaline concentration in the solution is controlled.3+ <120g / L, solution temperature 45-60℃, soaking time 30s-15min;

[0140] S5 secondary water washing involves rinsing the substrate with an acidic aqueous solution (pH = 2-3);

[0141] S6 neutralization involves immersing the substrate in a sulfuric acid aqueous solution; the concentration of the sulfuric acid aqueous solution is 140-250 g / L, and the immersion time is 2-5 min.

[0142] S7 involves three water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate.

[0143] S8 oxidation is performed using an aqueous sulfuric acid solution at a concentration of 140-190 g / L. The solution temperature is controlled at 18-22℃, the voltage at 15-18V, and the current at 100-150 A / m. 2 The energizing time is 20-37 minutes, and an oxide film with a thickness of 1-20 μm is formed on the surface of the substrate;

[0144] S9 involves four water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate.

[0145] S10 sealing is performed using the high-brightness aluminum alloy sealing agent prepared above; the temperature is 45-65℃.

[0146] S11 involves five water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate;

[0147] S12 drainage: Use an acidic solution with pH = 4-6.

[0148] The result is a high-brightness aluminum alloy material. The test results are shown in Table 3.

[0149] Table 3. Results data obtained in Example 8

[0150]

[0151] As can be seen, the high-gloss aluminum alloy material obtained in this embodiment exhibits a high-gloss surface film with a coating thickness greater than 10 μm, ranging from 11 to 13 μm. The coating hardness is 4-5H, making it resistant to scratches from hard objects. It demonstrates high adhesion, resistance to neutral salt spray (generally around 1000 hours is considered salt spray resistance, but in this embodiment it exceeds 1500 hours, showing even better performance), and acid resistance exceeding 72 hours, demonstrating even better performance. Comparative Example 1, with a lower filler dosage, resulted in a duller aluminum alloy material with a coating thickness less than 10 μm. Its adhesion was slightly inferior, and it was not resistant to neutral salt spray. While it possessed some acid resistance, it was less effective than that of the present invention. Comparative Example 2 used a commercially available alkaline aqueous solution of ethylene-acrylic acid (grafting rate 14%). The resulting aluminum alloy material had a certain gloss on its surface, but it was far from achieving a high-gloss effect. The coating thickness was less than 10 μm. The coating hardness was 3H, making it easily scratched by hard objects. It had poor adhesion, was not resistant to neutral salt spray, and had some acid resistance, but it was worse than the acid resistance of the present invention.

[0152] See Figure 1 . Figure 1 This describes the effect of the sealing agent on the anodic oxide film in this embodiment, sealing the anodic oxide pores and preventing further corrosion. A smooth, transparent film is formed on the surface, as shown by the horizontal bar, producing a high-gloss effect.

[0153] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A high-brightness aluminum alloy sealing agent, characterized in that, The product contains the following ingredients by weight: 100-120 parts of ethylene-acrylic acid emulsion with a grafting rate of 18-22; 25-35 parts of filler; 10-15 parts of diluent; 2-4 parts of film-forming aid; and 10-20 parts of deionized water. The method for preparing the ethylene-acrylic acid emulsion with a grafting rate of 18-22 includes the following steps: Step 1: Add 40-50 parts of polyethylene wax to 80-100 parts of deionized water, heat to 50-80℃, and after the polyethylene wax melts and the water separates into layers, add 0.5-1 parts of surfactant and 0.5-0.8 parts of initiator to maintain the temperature at 50-80℃. Step 2: Slowly add 15 parts of acrylic monomer, and the solution will change from colorless and transparent to slightly milky white; Step 3: After the addition is complete, add 1-2 parts buffer, 1-2 parts stabilizer, 0.5-1 part ammonia, and then add an appropriate amount of 45-55% NaOH to adjust the pH to 7-8, thus obtaining a semi-transparent white ethylene acrylic emulsion. The molecular weight of the polyethylene wax is 800-1000; The surfactant is either sodium dodecyl sulfate or sodium dodecyl sulfonate. The initiator is any one of potassium persulfate, ammonium persulfate, and sodium persulfate; The stabilizer is polyvinyl alcohol.

2. The high-brightness aluminum alloy sealing agent as described in claim 1, characterized in that, The product contains the following ingredients by weight: 100-115 parts of ethylene-acrylic emulsion with a grafting rate of 18-22; 25-35 parts of filler; 10-15 parts of diluent; 2-4 parts of film-forming aid; and 10-20 parts of deionized water.

3. The high-brightness aluminum alloy sealing agent according to claim 1, characterized in that, The buffer is any one of sodium bicarbonate, potassium dihydrogen phosphate, and sodium acetate.

4. The high-brightness aluminum alloy sealing agent according to claim 1, characterized in that, In step two, the acrylic monomer is added dropwise over 20 minutes.

5. The high-brightness aluminum alloy sealing agent as described in claim 1, characterized in that, The filler is a mixture of equal masses of titanium dioxide and basic magnesium carbonate; the diluent is ethanol; and the film-forming aid is propylene glycol ethyl ether or propylene glycol butyl ether.

6. The high-brightness aluminum alloy sealing agent as described in claim 1, characterized in that, The preparation method involves dissolving ethylene-acrylic acid emulsion in deionized water; then adding a film-forming aid and stirring until homogeneous; and finally adding a diluent and a filler.

7. A high-brightness aluminum alloy sealing process, characterized in that, The high-brightness aluminum alloy sealing agent according to any one of claims 1-6 was used.

8. The high-brightness aluminum alloy sealing process as described in claim 7, characterized in that, Includes the following steps, S1 Hanging Material: Grind off the oxide film on the edges of the hanging rod to expose the white area. If there is dead paint attached to the hanging rod, remove the dead paint. Check whether the quality of the aluminum alloy substrate meets the requirements, and fix the substrate that meets the requirements to the hanging rod. S2 Low-Temperature Polishing: The substrate is immersed in a sulfuric acid aqueous solution; S3 First water wash: The substrate is rinsed with an acidic aqueous solution; S4 Alkaline Etching: The substrate is immersed in an aqueous sodium hydroxide solution; S5 Secondary water wash, in which the substrate is rinsed with an acidic aqueous solution; S6 neutralization, the substrate is soaked in sulfuric acid aqueous solution; S7 involves three water washes, in which the substrate is rinsed with an acidic aqueous solution; S8 oxidation, using an aqueous sulfuric acid solution for anodic oxidation. S9 involves four water washes, in which the substrate is rinsed with an acidic aqueous solution; S10 sealing, using the aforementioned high-brightness aluminum alloy sealing agent; S11 involves five water washes, in which the substrate is rinsed with an acidic aqueous solution; S12 drain.

9. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, In the S2 polishing process, the concentration of the sulfuric acid aqueous solution is 140-190 g / L, and the immersion time is 1-5 min.

10. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, The first, second, third, fourth, and fifth water washes are each independently performed using an acidic aqueous solution with a pH of 2-3.

11. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, In the S4 alkaline etching process, the concentration of the sodium hydroxide aqueous solution is 50-80 g / L, and the Al concentration in the solution is controlled. 3+ <120g / L, solution temperature 45-60℃, soaking time 30s-15min.

12. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, In the S6 neutralization step, the concentration of the sulfuric acid aqueous solution is 140-250 g / L, and the soaking time is 2-5 min.

13. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, In the S8 anodizing process, the concentration of the sulfuric acid aqueous solution is 140-190 g / L, the solution temperature is controlled at 18-22℃, the voltage is 15-18V, and the current is 100-150 A / m. 2 The energizing time is 20 to 37 minutes, forming an oxide film with a thickness of 1 to 20 μm on the surface of the substrate.

14. The high-brightness aluminum alloy sealing process as described in claim 8, characterized in that, In the S10 sealing process, the groove contains the high-brightness aluminum alloy sealing agent, and the temperature is 45-65℃.

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