A matte aluminum alloy sealing agent and its sealing process

Abstract

This invention discloses a matte aluminum alloy sealing agent and its sealing process. The matte aluminum alloy sealing agent comprises the following raw materials by weight: 60-80 parts of polyethylene acrylic acid with a grafting rate of 18-22; 10-15 parts of diluent; 15-20 parts of filler; 1-2 parts of film-forming aid; and 120-145 parts of deionized water. The matte aluminum alloy sealing agent not only improves the corrosion resistance of the aluminum alloy, but also, to achieve a decorative appearance, gives the treated aluminum alloy surface a matte luster, resulting in a luxurious and textured surface.

Description

Technical Field

[0001] This invention relates to the field of aluminum profile surface treatment technology, and in particular to a matte 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 matte 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 surface of the aluminum alloy treated by this process a matte luster, making the surface luxurious and textured.

[0006] To achieve the above objectives, the present invention provides a matte aluminum alloy sealing agent, characterized in that it comprises the following raw materials by weight: 60-80 parts of polyethylene acrylic acid with a grafting rate of 18-22; 10-15 parts of diluent; 15-20 parts of filler; 1-2 parts of film-forming aid; and 120-145 parts of deionized water.

[0007] Further, 60-80 parts of polyethylene acrylic acid with a grafting rate of 18-22; 10-15 parts of diluent; 15-19 parts of filler; 1-2 parts of film-forming aid; 120-145 parts of deionized water.

[0008] Furthermore, the polyethylene acrylic acid is a solid powder, and the preparation method includes the following steps:

[0009] Step 1: Add 50-60 parts of polyethylene wax to 40-50 parts of butyl acetate, stir to dissolve, and then add 0.1-0.2 parts of initiator;

[0010] Step 2: Slowly add 10 parts of acrylic monomer dropwise. The solution will start to turn white. After the addition is complete, add 0.1-0.2 parts of initiator. The white precipitate in the solution at this point is polyethylene acrylic acid.

[0011] Step 3: Filter off the clear liquid on top of the solution, and vacuum dry the white precipitate at the bottom to obtain polyethylene acrylic powder.

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

[0013] Optionally, the initiator is either potassium persulfate or ammonium persulfate.

[0014] Optional, slowly drip in 10 parts of acrylic monomer over 14-16 minutes.

[0015] Furthermore, the diluent is propylene glycol; the filler is a mixture of graphite and ferrous oxide in equal mass; and the film-forming aid is hexadecyl alcohol ester or dodecyl alcohol ester.

[0016] 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 filler.

[0017] The present invention also provides a matte aluminum alloy sealing process, characterized in that the aforementioned matte aluminum alloy sealing agent is used.

[0018] Furthermore, the following steps are included:

[0019] 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.

[0020] S2 polishing: The substrate is immersed in an aqueous sulfuric acid solution;

[0021] S3 First water wash: The substrate is rinsed with an acidic aqueous solution;

[0022] S4 Alkaline Etching: The substrate is immersed in an aqueous sodium hydroxide solution;

[0023] S5 Secondary water wash, in which the substrate is rinsed with an acidic aqueous solution;

[0024] S6 neutralization, the substrate is soaked in sulfuric acid aqueous solution;

[0025] S7 involves three water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0026] S8 oxidation, using an aqueous sulfuric acid solution for anodic oxidation.

[0027] S9 involves four water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0028] S10 sealing is performed using any of the matte aluminum alloy sealing agents described in claims 1-6;

[0029] S11 involves five water washes, in which the substrate is rinsed with an acidic aqueous solution;

[0030] S12 drain.

[0031] 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;

[0032] 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.

[0033] 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;

[0034] 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;

[0035] 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 to 37 minutes, and an oxide film with a thickness of 1 to 20 μm or more is formed on the surface of the substrate.

[0036] Optionally, in the S10 sealing process, the groove contains the matte aluminum alloy sealing agent, and the temperature is 45-65℃;

[0037] Optionally, S12 dewatering uses an acidic solution with pH = 4-6.

[0038] The polyethylene acrylic acid used in this invention is synthesized by grafting low molecular weight polyethylene wax with acrylic acid. This process allows for the synthesis of polyethylene acrylic acid under simple environmental conditions, without requiring high temperature and pressure. The formulation is simple and the operation is convenient. This method overcomes the harsh conditions of requiring ethylene gas to be introduced into the acrylic acid solution under high temperature and pressure, simplifying the process. In the preparation of polyethylene acrylic acid, the use of low molecular weight polyethylene wax significantly increases the grafting rate of acrylic acid (18-22%). A selected co-solvent makes the polyethylene acrylic acid powder soluble in water at room temperature, which can be used to prepare a metal plating sealant. In the neutral salt spray test of the metal plating sealant, it can reach approximately 1500 hours, far exceeding existing technologies, demonstrating excellent metal sealant performance. It can also be used to prepare anti-corrosion coatings, exhibiting good corrosion resistance. In the preparation of polyethylene acrylic acid, butyl acetate is used as a solvent during the grafting reaction. This solvent is safe and non-toxic, overcoming the disadvantages of petroleum ether being flammable and explosive.

[0039] The matte aluminum alloy sealing agent of this invention does not require the addition of other additives. The matte aluminum alloy prepared according to the matte aluminum alloy sealing process of this invention has a matte 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

[0040] Figure 1 This is a diagram showing the effect of the sealing agent obtained in this invention on anodized films. Detailed Implementation

[0041] 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.

[0042] The following testing methods are included:

[0043] 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.

[0044] The formula for calculating the grafting rate is as follows:

[0045] (Molar amount of sodium hydroxide - molar amount of hydrochloric acid) * 70.06 / 0.5 * 100%.

[0046] Coating thickness: Measured according to GB 1764-79.

[0047] Hardness of the coating: determined according to GB / T 6739-1996.

[0048] The adhesion of the coating was determined according to GB / T 1720-79(89).

[0049] Salt spray resistance test: Refer to GB / T 10125-2012 and use the neutral salt spray test.

[0050] Acid resistance (accelerated copper sulfate) test: The test shall be conducted in accordance with GB / T 10125-2012.

[0051] Example 1: Preparation of poly(acrylic acid)

[0052] This embodiment provides a process for preparing low molecular weight polyethylene wax and acrylic acid to synthesize polyethylene acrylic acid, including the following steps:

[0053] Step 1: Add 50-60 parts of polyethylene wax to 40-50 parts of butyl acetate, stir to dissolve, and then add 0.1-0.2 parts of initiator;

[0054] Step 2: Slowly add 10 parts of acrylic acid monomer dropwise. The solution will start to turn white. After the addition is complete, add 0.1-0.2 parts of initiator. The white precipitate in the solution at this point is the polyvinyl acrylic acid. Adding the initiator a second time is beneficial for the full reaction.

[0055] Step 3: Filter off the supernatant of the solution, filter under reduced pressure with ethanol to obtain white solid polyethylene acrylic acid, and dry to obtain polyethylene acrylic acid powder.

[0056] Step 4: Take 20-30g of polyethylene acrylic powder, add it to 200ml of water, heat it to 80℃, and then add 2-3g of co-solvent to obtain a polyethylene acrylic solution.

[0057] In this embodiment, the molecular weight of the polyethylene wax is 800-1000, and the low molecular weight is beneficial to the high grafting rate of acrylic acid.

[0058] In step two of this embodiment, 10 parts of acrylic monomer are slowly dripped in over 14-16 minutes.

[0059] In this embodiment, the initiator is either potassium persulfate or ammonium persulfate, and the initiator enables the grafting reaction between polyethylene wax and acrylic monomer.

[0060] The co-solvent is any one of sodium salicylate, p-aminobenzoic acid, nicotinamide, and acetamide. The co-solvent enables the polyethylene acrylic powder to dissolve in water.

[0061] It also includes a method for measuring the grafting rate of acrylic acid, in which polyethylene acrylic powder is extracted with acetone for 20-24 hours, 0.5g is dissolved in hot xylene, then neutralized with sodium hydroxide-ethanol solution, phenolphthalein is used as an indicator, excess alkali is back-titrated with hydrochloric acid, and finally the grafting rate is measured.

[0062] Multiple experiments were conducted using the preparation process of low molecular weight polyethylene wax and acrylic acid to synthesize polyethylene acrylic acid as described in this embodiment. The following section selects several experimental groups and control groups to further illustrate the beneficial effects of the preparation process of low molecular weight polyethylene wax and acrylic acid to synthesize polyethylene acrylic acid as described in this embodiment.

[0063] Experimental Group 1

[0064] Add 50 parts of polyethylene wax with a molecular weight of 800-1000 to 40 parts of butyl acetate, stir to dissolve, and then add 0.1 parts of initiator (potassium persulfate, the same below); then slowly add 10 parts of acrylic monomer over 15 minutes, the solution begins to turn white, and after the addition is complete, add another 0.1 parts of initiator; at this point, the white precipitate in the solution is polyethylene acrylic acid; filter out the upper clear liquid of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0065] Experimental Group 2

[0066] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0067] Experimental Group 3

[0068] Add 60 parts of polyethylene wax with a molecular weight of 800-1000 to 50 parts of butyl acetate, stir to dissolve, and then add 0.2 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.2 parts of initiator; at this point, the white precipitate in the solution is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0069] Experimental Group 4

[0070] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0071] Experimental Group 5

[0072] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0073] Comparison Group 1

[0074] Add 55 parts of polyethylene wax with a molecular weight of 1000-8000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; at this point, the white precipitate in the solution is polyethylene acrylic acid; filter out the upper clear liquid of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder.

[0075] Comparison Group 2

[0076] Add 40 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0077] Comparison Group 3

[0078] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 35 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0079] Comparison Group 4

[0080] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of petroleum ether, stir to dissolve, and then add 0.15 parts of initiator; then slowly add 10 parts of acrylic monomer dropwise over 15 minutes, the solution begins to turn white, and after the dropwise addition is complete, add another 0.15 parts of initiator; the white precipitate in the solution at this point is polyethylene acrylic acid; filter out the supernatant of the solution, and vacuum dry the lower white precipitate to obtain polyethylene acrylic acid powder, and measure the grafting rate of acrylic acid.

[0081] Comparison Group 5

[0082] Add 55 parts of polyethylene wax with a molecular weight of 800-1000 to 45 parts of butyl acetate, stir to dissolve, and then add 0.15 parts of initiator; then add 10 parts of acrylic monomer rapidly over 7-8 minutes. The solution begins to turn white. After the addition is complete, add another 0.15 parts of initiator. However, if the acrylic acid is added too quickly, it will clump together and form a white waxy hard solid, and the reaction cannot continue.

[0083] Table 1. Comparison of components and experimental phenomena in each experimental group and control group.

[0084]

[0085] According to the experimental results in Table 1:

[0086] 1. Comparing groups one through three with the five experimental groups, it is evident that using low molecular weight polyethylene wax to graft acrylic acid significantly increases the grafting rate of acrylic acid; the grafting rate in experimental groups one through five was 18-22%. Polyethylene acrylic acid produced using high molecular weight polyethylene wax is insoluble in water, limiting its application environment; using too little polyethylene wax will generate excess polyacrylic acid impurities, forming a mixed powder with the polyethylene acrylic acid, resulting in a mixed powder that is insoluble in water, further limiting its application environment.

[0087] 2. Compared with the five experimental groups, the use of butyl acetate as a solvent in the grafting reaction process shows that the solvent is safe and non-toxic, overcoming the disadvantages of petroleum ether being flammable and explosive, and also improving the grafting rate of acrylic acid.

[0088] 3. Compared with the five experimental groups, it can be seen that the 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.

[0089] Example 2: Preparation of matte aluminum alloy sealing agent

[0090] A matte aluminum alloy sealing agent was prepared using the polyethylene acrylic powder prepared in Experiment Group 1.

[0091] According to the dosage in Table 2, dissolve the polyethylene acrylic powder in deionized water at a temperature of about 45°C, then add hexadecyl alcohol ester and stir evenly. Finally, add propylene glycol and a mixture of graphite and ferrous oxide (1:1 mass ratio).

[0092] Table 2. Raw material usage (parts by weight) for matte aluminum alloy sealant.

[0093]

[0094] Example 3: Preparation of matte aluminum alloy sealing agent

[0095] The materials are shown in Table 2. The polyethylene acrylic powder was prepared in Experimental Group 1, and the film-forming aid was hexadecyl alcohol ester.

[0096] The preparation method is the same as in Example 2.

[0097] Example 4: Preparation of matte aluminum alloy sealing agent

[0098] The materials are shown in Table 2. The polyethylene acrylic powder was prepared in Experimental Group 1, and the film-forming aid was dodecyl alcohol ester. The preparation method was the same as in Example 2.

[0099] Example 5: Preparation of matte aluminum alloy sealing agent

[0100] The materials are shown in Table 2. The polyethylene acrylic powder was prepared in Experimental Group 2, and the film-forming aid was hexadecyl alcohol ester.

[0101] The preparation method is the same as in Example 2.

[0102] Example 6: Preparation of matte aluminum alloy sealing agent

[0103] The materials are shown in Table 2. The polyethylene acrylic powder was prepared in Experimental Group 2, and the film-forming aid was hexadecyl alcohol ester. The preparation method was the same as in Example 2.

[0104] Example 7: Preparation of matte aluminum alloy sealing agent

[0105] The materials are shown in Table 2. The polyethylene acrylic powder was prepared in Experimental Group 2, and the film-forming aid was dodecyl alcohol ester.

[0106] The preparation method is the same as in Example 2.

[0107] Comparative Example 1:

[0108] The materials are shown in Table 2. Same as Example 2, but without filler.

[0109] The preparation method is the same as in Example 2.

[0110] Comparative Example 2

[0111] The materials are shown in Table 2. Similar to Example 2, the polyvinyl acrylic acid prepared in this invention was replaced with a commercially available hot alkaline aqueous solution of ethylene acrylic acid (grafting rate 14%).

[0112] The preparation method is the same as in Example 2.

[0113] Example 8: Matte Aluminum Alloy Sealing Process

[0114] 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.

[0115] 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;

[0116] S3 Single water wash: The substrate is rinsed with an acidic aqueous solution (pH=2-3);

[0117] 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;

[0118] S5 secondary water washing involves rinsing the substrate with an acidic aqueous solution (pH = 2-3);

[0119] 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.

[0120] S7 involves three water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate.

[0121] 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. 2The energizing time is 20 to 37 minutes, and an oxide film with a thickness of 1 to 20 μm or more is formed on the surface of the substrate.

[0122] S9 involves four water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate.

[0123] S10 sealing is performed using the matte aluminum alloy sealing agent prepared above; the temperature is 45-65℃.

[0124] S11 involves five water washes, using an acidic aqueous solution (pH = 2-3) to rinse the substrate;

[0125] S12 drainage: Use an acidic solution with pH = 4-6.

[0126] The resulting material is a matte aluminum alloy. The test results are shown in Table 3.

[0127] Table 3. Results data obtained in Example 8

[0128]

[0129] As can be seen, the matte aluminum alloy material obtained in this embodiment has a matte 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 exhibits 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 (generally 24-48 hours is considered acid resistance, but in this embodiment it reaches >72 hours, showing even better performance). Comparative Example 1, without filler, produces an aluminum alloy material with no matte surface; its adhesion is slightly lower, it is not resistant to neutral salt spray, and while it has some acid resistance, it is inferior to the acid resistance of this 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 slightly matte surface, but it was far from achieving the matte effect of the present invention. The coating thickness was less than 10 μm. The coating 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.

[0130] 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 barred portion, producing a matte finish.

[0131] 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 matte aluminum alloy sealing agent, characterized in that, By weight, it contains the following raw materials: 60-80 parts of polyethylene acrylic acid with a grafting rate of 18-22; 10-15 parts of diluent; 15-20 parts of filler; 1-2 parts of film-forming aid; and 120-145 parts of deionized water. The polyethylene acrylic acid with a grafting rate of 18-22 is a solid powder, and its preparation method includes the following steps: Step 1: Add 50-60 parts of polyethylene wax to 40-50 parts of butyl acetate, stir to dissolve, and then add 0.1-0.2 parts of initiator; Step 2: Slowly add 10 parts of acrylic monomer dropwise. The solution will start to turn white. After the addition is complete, add 0.1-0.2 parts of initiator. The white precipitate in the solution at this point is polyethylene acrylic acid. Step 3: Filter off the clear liquid on the top layer of the solution, and vacuum dry the white precipitate at the bottom layer to obtain polyethylene acrylic powder; The molecular weight of the polyethylene wax is 800-1000; The initiator is either potassium persulfate or ammonium persulfate. The 10 parts of acrylic monomer were slowly dripped in over 14-16 minutes.

2. The matte aluminum alloy sealing agent as described in claim 1, characterized in that, 60-80 parts of polyethylene acrylic acid with a grafting rate of 18-22; 10-15 parts of diluent; 15-19 parts of filler; 1-2 parts of film-forming aid; 120-145 parts of deionized water.

3. The matte aluminum alloy sealing agent as described in claim 1, characterized in that, The diluent is propylene glycol; the filler is a mixture of equal masses of graphite and ferrous oxide; and the film-forming aid is hexadecyl alcohol ester or dodecyl alcohol ester.

4. The matte aluminum alloy sealing agent as described in claim 1, characterized in that, The matte aluminum alloy sealing agent is prepared by dissolving polyethylene acrylic acid in deionized water; then adding a film-forming aid and stirring evenly; and finally adding a diluent and filler.

5. A matte aluminum alloy sealing process, characterized in that, The matte aluminum alloy sealing agent according to any one of claims 1-4 was used.

6. The matte aluminum alloy sealing process as described in claim 5, 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 polishing: The substrate is immersed in an aqueous sulfuric acid 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 matte aluminum alloy sealing agent; S11 involves five water washes, in which the substrate is rinsed with an acidic aqueous solution; S12 drains water.

7. The matte aluminum alloy sealing process as described in claim 6, 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.

8. The matte aluminum alloy sealing process as described in claim 6, 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.

9. The matte aluminum alloy sealing process as described in claim 6, characterized in that, In S4 alkaline etching, the concentration of the sodium hydroxide aqueous solution is 50-80 g / L, controlling the Al concentration in the solution. 3+ <120g / L, solution temperature 45-60℃, soaking time 30s-15min.

10. The matte aluminum alloy sealing process as described in claim 6, characterized in that, In step S6, the concentration of the sulfuric acid aqueous solution is 140-250 g / L, and the soaking time is 2-5 min.

11. The matte aluminum alloy sealing process as described in claim 6, characterized in that, 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 to 37 minutes, and an oxide film with a thickness of 1-20 μm or more is formed on the surface of the substrate.

12. The matte aluminum alloy sealing process as described in claim 6, characterized in that, In the S10 sealing process, the groove contains the matte aluminum alloy sealing agent, and the temperature is 45-65℃.

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