An aluminum alloy with surface-loaded bio-based antibacterial components and its preparation method

Abstract

This invention relates to the field of metal surface treatment technology, and more particularly to an aluminum alloy with a surface loaded with bio-based antibacterial components and its preparation method. The aluminum alloy is prepared by the following steps: anodizing the treated aluminum alloy to obtain an aluminum alloy with a nanotube pore structure; immersing the obtained nanotube pore structure anodic aluminum layer in a silane coupling agent solution for activation treatment to obtain a surface-activated aluminum alloy; immersing the surface-activated aluminum alloy in an epoxy resin solution containing antibacterial components and allowing it to stand for 10–12 hours, then removing the aluminum alloy and curing it at 70–75°C for 2–3 hours to obtain the aluminum alloy. The aluminum alloy prepared by this invention simultaneously loads two antibacterial components, palmatine and magnolol, onto the anodic oxide film layer, which synergistically produce a better inhibitory effect on fungi and bacteria.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and in particular to an aluminum alloy with a surface loaded with bio-based antibacterial components and its preparation method. Background Technology

[0002] Antibacterial functionalization of aluminum alloy surfaces does not alter the microstructure and elemental composition of the aluminum alloy itself; it only modifies the surface for antibacterial purposes. Compared to preparing alloy-type aluminum alloys, the biggest advantage of aluminum alloy surface modification is that it can directly modify already formed aluminum alloys, and the process is simple, making it the most commonly chosen method for antibacterial functionalization of aluminum alloys. As an inorganic metal material, the most common surface modification method for aluminum alloys is still coating them with an antibacterial coating. Dogan prepared Ag and Zn-supported zeolite using an ion exchange method, then mixed the antibacterial zeolite into vinyl acetate varnish, and coated it onto aluminum foil to obtain a 6-10 mm thick antibacterial coating, which showed good antibacterial effects against Escherichia coli. Zhang Weili et al. used the sol-gel method, mixing TiO2 into tetrabutyl titanate to prepare a sol, and then prepared a dense TiO2 antibacterial film on the aluminum alloy surface, exhibiting certain antibacterial activity. Antibacterial coating of aluminum alloy surfaces is currently a widely used method, simple and convenient, but coating aging and peeling can easily lead to poor long-term antibacterial efficacy. Furthermore, anodizing of aluminum alloy surfaces is a very mature surface treatment process that can produce a dense oxide film. The uniform and regular nanopores on the surface become excellent sites for functional ion deposition. Many functionalizations of aluminum alloy surfaces are achieved through a two-step method: first, surface anodizing is performed, and then a layer of effective active ingredients is deposited. Antibacterial functionalization of aluminum alloy surfaces can also be achieved through this two-step method. Tomioka et al. used anodizing to form AAO on the surface of aluminum alloys, and then filled the pores of the AAO surface with silver thiosulfate complexes to prepare aluminum alloy products with good antibacterial properties. This method of preparing aluminum alloys allows for a wide range of choices of antibacterial ingredients, but it is not suitable for irregularly shaped aluminum alloy components. In addition, anodizing can produce very regular nanoporous structures, but particle deposition does not require such regular pore structures, so the anodizing method is too complex and energy-intensive.

[0003] Coptis chinensis, the dried rhizome of the Ranunculaceae plant Coptis chinensis Franch., is named for its beaded, yellow rhizome. It is a commonly used antibacterial and antiviral traditional Chinese medicine. Coptis chinensis has a broad antibacterial spectrum, exhibiting inhibitory effects against Gram-positive and Gram-negative bacteria, various types of influenza viruses, and fungi. Its main components are isoquinoline alkaloids, with berberine being the most abundant, followed by palmatine. Palmatine, berberine, epiberberine, and coptisine are all isoquinoline alkaloids found in Coptis chinensis, with similar molecular weights but different structures. The order of activity against Staphylococcus aureus is berberine, coptisine > palmatine, epiberberine; the order of activity against Escherichia coli is coptisine > berberine > epiberberine > palmatine. Bamatin is the second most abundant alkaloid component in Coptis chinensis, but it has the lowest antibacterial activity, and its practicality needs further development.

[0004] Mold is extremely resilient. Mold spores are ubiquitous in the atmosphere, and once conditions are right, they can rapidly grow and reproduce, attaching to material surfaces, accelerating corrosion, and shortening material lifespan. The corrosive effects of mold vary depending on the environment. Stoica et al. immersed 304 stainless steel in disinfectant and a mixture of disinfectant and fungal suspension, and the corrosion results were different. The filamentous structure of mold allows it to better adhere to metal surfaces, forming a complete biofilm. Therefore, *Aspergillus niger* corrodes carbon steel less than yeast. Furthermore, the synergistic effect of fungi and disinfectants increases the solution conductivity, and the corrosion potential shifts positively with increasing immersion time. The dense oxide film formed on aluminum alloy surfaces gives them good corrosion resistance and is often used as a lightweight structural material in important fields. Once the oxide film on aluminum alloy surfaces breaks, corrosion in the broken areas will accelerate. For aluminum alloy materials exposed to humid and hot environments, mold readily adheres to the surface, forming a biofilm. The uneven distribution of mold film on the material surface and the metabolic products it produces can accelerate the damage of the oxide film to some extent, thus shortening the service life of aluminum alloy materials.

[0005] Based on the above, this invention proposes an aluminum alloy with surface-loaded bio-based antibacterial components and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to provide an aluminum alloy with a surface loaded with bio-based antibacterial components and its preparation method.

[0007] To achieve the above objectives, the present invention provides an aluminum alloy with a surface loaded with bio-based antibacterial components, wherein the aluminum alloy is prepared by the following steps:

[0008] (1) Use 1000# to 2000# sandpaper to polish the aluminum alloy surface step by step, and rinse with anhydrous ethanol after polishing;

[0009] (2) The treated aluminum alloy is subjected to anodizing treatment. The specific conditions and parameters of the anodizing are as follows: the anodizing solution is a 25% phosphoric acid aqueous solution, the anodizing voltage is 60V, and the time is 15-20min. After the aluminum alloy is anodized, an aluminum alloy with a nanotube pore structure is obtained.

[0010] (3) Add silane coupling agent to 90% ethanol to prepare a silane coupling agent solution with a volume fraction of 15-17%. The anodic aluminum oxide layer with nanotube pore structure obtained in step (2) is immersed and activated by the silane coupling agent solution for 15-20 min to obtain a surface-activated aluminum alloy.

[0011] (4) Take epoxy resin and silane coupling agent and mix them evenly at a mass ratio of 10:1 to 2 to form an epoxy resin liquid. Then add antibacterial components to make the epoxy resin liquid contain 260 to 300 g / L of antibacterial components. Stir evenly and immerse the surface-activated aluminum alloy in the epoxy resin liquid and let it stand for 10 to 12 hours. Then take out the aluminum alloy and place it at 70 to 75°C for 2 to 3 hours to cure, thus obtaining the aluminum alloy.

[0012] Preferably, the epoxy resin is magnolol-based epoxy resin.

[0013] Preferably, the magnolol-based epoxy resin is prepared by the following method: magnolol, epichlorohydrin, and benzyltriethylammonium chloride are mixed in a molar ratio of 20:1:2 and reacted under reflux at 80°C for 3 hours while maintaining a nitrogen atmosphere. Subsequently, an aqueous solution containing 40.0% sodium hydroxide by mass is added dropwise, and the reaction continues for 1 hour. After the reaction is completed, the resin is subjected to filtration, extraction, separation, and rotary evaporation in sequence, and then dried in a vacuum oven at 55-60°C until constant weight is obtained.

[0014] Preferably, the antibacterial component is berberine alkaloid, including one of berberine, coptisine, palmatine, and epiberberine.

[0015] Preferably, the antibacterial ingredient is Bamatin, CAS number 102321-59-5, with a purity greater than 98%.

[0016] Preferably, the silane coupling agent in step (3) is a silane coupling agent containing a mercapto group.

[0017] Preferably, the thiol-containing silane coupling agent includes one of 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0018] Preferably, the mercapto-containing silane coupling agent is 3-mercaptopropyltriethoxysilane.

[0019] Preferably, the silane coupling agent in step (4) is an epoxy silane coupling agent.

[0020] Preferably, the epoxy silane coupling agent includes one of 3-glycidyl etheroxypropyltriethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldimethoxysilane, and 3-glycidyl etheroxypropylmethyldiethoxysilane.

[0021] Preferably, the epoxy silane coupling agent is 3-glycidoxypropyltrimethoxysilane.

[0022] Preferably, the aluminum alloy is a 7-series aluminum alloy.

[0023] The present invention also provides the use of the aluminum alloy with the surface loaded with bio-based antibacterial components in the preparation of antibacterial surgical instruments.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The aluminum alloy prepared by this invention simultaneously loads two antibacterial components, palmatine and magnolol, on the anodic oxide film layer. The two components work synergistically to produce a better inhibitory effect on fungi and bacteria. Among them, magnolol, as one of the components of epoxy resin, has a stable complex structure that makes the prepared antibacterial surface layer have better heat resistance and moisture resistance, making its antibacterial effect more durable.

[0026] 2. The raw materials for this invention are abundant and reasonably priced in China, which means that there are no high cost restrictions on its large-scale production; at the same time, aluminum alloys are simple and the overall production cost is not high, which is conducive to large-scale industrial production. Detailed Implementation

[0027] Example 1

[0028] The preparation steps are as follows:

[0029] (1) Take magnolol, epichlorohydrin and benzyltriethylammonium chloride in a molar ratio of 20:1:2 and react them under reflux at 80°C for 3 hours while maintaining a nitrogen atmosphere. Then, add an aqueous solution containing 40.0% sodium hydroxide dropwise and continue the reaction for 1 hour. After the reaction is completed, filter, extract, separate the liquid and evaporate the liquid in sequence. Place the solution in a vacuum oven at 55-60°C and dry it to constant weight to obtain magnolol-based epoxy resin for later use.

[0030] (2) Use 1000# to 2000# sandpaper to polish the surface of 7075 aluminum alloy step by step, and rinse with anhydrous ethanol after polishing;

[0031] (3) The treated aluminum alloy is subjected to anodizing treatment. The specific conditions and parameters of the anodizing are as follows: the anodizing solution is a 25% phosphoric acid aqueous solution, the anodizing voltage is 60V, and the time is 15min. After the aluminum alloy is anodized, an aluminum alloy with a nanotube pore structure is obtained.

[0032] (4) Add 3-mercaptopropyltriethoxysilane to 90% ethanol to prepare a silane coupling agent solution with a volume fraction of 15%. The anodic aluminum oxide layer with nanotube pore structure obtained in step (3) is immersed and activated by the silane coupling agent solution for 20 min to obtain a surface-activated aluminum alloy.

[0033] (5) Take magnolol epoxy resin and 3-glycidoxypropyltrimethoxysilane and mix them evenly at a mass ratio of 10:1 to form an epoxy resin liquid. Then add Bamatin to make the epoxy resin liquid contain 260g / L of Bamatin. Stir evenly and immerse the surface-activated aluminum alloy in the epoxy resin liquid and let it stand for 10h. Then take out the aluminum alloy and place it at 70℃ for 3h to cure, thus obtaining the aluminum alloy.

[0034] Example 2

[0035] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0036] (1) Take magnolol, epichlorohydrin and benzyltriethylammonium chloride in a molar ratio of 20:1:2 and react them under reflux at 80°C for 3 hours while maintaining a nitrogen atmosphere. Then, add an aqueous solution containing 40.0% sodium hydroxide dropwise and continue the reaction for 1 hour. After the reaction is completed, filter, extract, separate the liquid and evaporate the liquid in sequence. Place the solution in a vacuum oven at 55-60°C and dry it to constant weight to obtain magnolol-based epoxy resin for later use.

[0037] (2) Use 1000# to 2000# sandpaper to polish the surface of 7075 aluminum alloy step by step, and rinse with anhydrous ethanol after polishing;

[0038] (3) The treated aluminum alloy is subjected to anodizing treatment. The specific conditions and parameters of the anodizing are as follows: the anodizing solution is a 25% phosphoric acid aqueous solution, the anodizing voltage is 60V, and the time is 20min. After the aluminum alloy is anodized, an aluminum alloy with a nanotube pore structure is obtained.

[0039] (4) Add 3-mercaptopropyltriethoxysilane to 90% ethanol to prepare a silane coupling agent solution with a volume fraction of 17%. The anodic aluminum oxide layer with nanotube pore structure obtained in step (3) is immersed and activated by the silane coupling agent solution for 15-20 min to obtain a surface-activated aluminum alloy.

[0040] (5) Take magnolol epoxy resin and 3-glycidoxypropyltrimethoxysilane and mix them evenly at a mass ratio of 10:2 to form an epoxy resin liquid. Then add Bamatin to make the epoxy resin liquid contain 280g / L of Bamatin. Stir evenly and immerse the surface-activated aluminum alloy in the epoxy resin liquid and let it stand for 12h. Then take out the aluminum alloy and place it at 75℃ for 2h to cure, thus obtaining the aluminum alloy.

[0041] Example 3

[0042] Weigh the specific raw materials according to Table 1. The preparation steps are as follows:

[0043] (1) Take magnolol, epichlorohydrin and benzyltriethylammonium chloride in a molar ratio of 20:1:2 and react them under reflux at 80°C for 3 hours while maintaining a nitrogen atmosphere. Then, add an aqueous solution containing 40.0% sodium hydroxide dropwise and continue the reaction for 1 hour. After the reaction is completed, filter, extract, separate the liquid and evaporate the liquid in sequence. Place the solution in a vacuum oven at 55-60°C and dry it to constant weight to obtain magnolol-based epoxy resin for later use.

[0044] (2) Use 1000# to 2000# sandpaper to polish the surface of 7075 aluminum alloy step by step, and rinse with anhydrous ethanol after polishing;

[0045] (3) The treated aluminum alloy is subjected to anodizing treatment. The specific conditions and parameters of the anodizing are as follows: the anodizing solution is a 25% phosphoric acid aqueous solution, the anodizing voltage is 60V, and the time is 20min. After the aluminum alloy is anodized, an aluminum alloy with a nanotube pore structure is obtained.

[0046] (4) Add 3-mercaptopropyltriethoxysilane to 90% ethanol to prepare a silane coupling agent solution with a volume fraction of 17%. The anodic aluminum oxide layer with nanotube pore structure obtained in step (3) is immersed and activated by the silane coupling agent solution for 20 min to obtain a surface-activated aluminum alloy.

[0047] (5) Take magnolol epoxy resin and 3-glycidoxypropyltrimethoxysilane and mix them evenly at a mass ratio of 10:1.5 to form an epoxy resin liquid. Then add Bamatin to make the epoxy resin liquid contain 300g / L of Bamatin. Stir evenly and immerse the surface-activated aluminum alloy in the epoxy resin liquid and let it stand for 12h. Then take out the aluminum alloy and place it at 75℃ for 3h to cure, thus obtaining the aluminum alloy.

[0048] Comparative Example 1

[0049] Unlike Example 3, no antibacterial ingredient, Bamatin, was added; the remaining preparation steps were the same as in Example 3.

[0050] Comparative Example 2

[0051] Unlike Example 3, the added antibacterial component is berberine, CAS number 2086-83-1, with a purity greater than 98%. The remaining preparation steps are the same as in Example 3.

[0052] Comparative Example 3

[0053] Unlike Example 3, the added antibacterial component was berberine, CAS number 3486-66-6, with a purity greater than 98%. The remaining preparation steps were the same as in Example 3.

[0054] Comparative Example 4

[0055] Unlike Example 3, a common epoxy resin was used, and magnolol was added to the epoxy resin solution in step (5) at a concentration of 500 g / L. The remaining preparation steps were the same as in Example 3.

[0056] Comparative Example 5

[0057] The difference from Example 3 is that the types of silane coupling agents used in steps (4) and (5) are interchanged. The remaining preparation steps are the same as in Example 3.

[0058] Performance Evaluation

[0059] Fungal inhibition performance test: The antifungal performance was tested using the mold test method. The specific steps of the antifungal performance test are as follows: (1) Clean the aluminum alloy sample with alcohol and distilled water, place it on a clean bench for later use, and then sterilize it with a UV sterilizing lamp. (2) Spray all sample surfaces evenly with a sprayer containing Aspergillus niger spore suspension. (3) Place all samples after spraying the spore suspension into a constant temperature incubator for incubation. The temperature of the constant temperature incubator is set to 28℃, and the incubation time is 14 days. At the same time, the humidity is kept above 90%. During the incubation process, the mold growth on the sample surface is observed regularly. After the incubation is completed, the area A of the moldy area on the sample surface and the sample surface area B are measured. The antifungal R is calculated according to formula (1): R=(BA) / B×100%. The specific results are shown in Table 1.

[0060] Bacterial inhibition performance test: 100 μL of Escherichia coli (ATCC8099) bacterial solution (10 5A CFU / mL solution was added dropwise to the surface of the aluminum alloy sample and placed in a biochemical incubator at 37°C for 1 hour. Then, the sample was washed with 900 μL of sterile phosphate-buffered saline (PBS). 100 μL of the washing solution was then evenly added dropwise to a nutrient agar plate, which was placed in an incubator at 37°C for 24 hours. Finally, the antibacterial rate of the sample was calculated based on the number of remaining colonies on the agar plate. The specific results are shown in Table 1.

[0061] Antibacterial stability test: The aluminum-based alloy samples of Example 3 and Comparative Examples 4 and 5 were placed in an environment with 85% humidity and 85°C for 10 hours, and then the antibacterial performance was tested again according to the above method. The specific results are shown in Table 2.

[0062] Table 1

[0063]

[0064] Table 2

[0065]

[0066]

[0067] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. An aluminum alloy surface loaded with a bio-based antimicrobial ingredient, characterized in that, The aluminum alloy is prepared by the following steps: (1) Use 1000# to 2000# sandpaper to polish the aluminum alloy surface step by step, and rinse with anhydrous ethanol after polishing; (2) The treated aluminum alloy is subjected to anodizing treatment. The specific conditions and parameters of the anodizing are as follows: the anodizing solution is a 25% phosphoric acid aqueous solution, the anodizing voltage is 60V, and the time is 15~20min. After the aluminum alloy is anodized, an aluminum alloy with a nanotube pore structure is obtained. (3) Add 3-mercaptopropyltriethoxysilane to 90% ethanol to prepare a silane coupling agent solution with a volume fraction of 15~17%. The anodic aluminum oxide layer with nanotube pore structure obtained in step (2) is immersed and activated by the silane coupling agent solution for 15~20 min to obtain a surface-activated aluminum alloy. (4) Take epoxy resin and 3-glycidoxypropyltrimethoxysilane and mix them evenly at a mass ratio of 10:1~2 to form an epoxy resin solution. Then add antibacterial components to make the epoxy resin solution contain 260~300g / L of antibacterial components. Stir evenly and immerse the surface-activated aluminum alloy in the epoxy resin solution and let it stand for 10~12h. Then take out the aluminum alloy and place it at 70~75℃ for 2~3h to cure, thus obtaining the aluminum alloy. The antibacterial component is Parmatin, CAS number 102321-59-5, and its purity is high. The epoxy resin is 98%; the epoxy resin is magnolol-based epoxy resin; the magnolol-based epoxy resin is prepared by the following method: magnolol, epichlorohydrin and benzyltriethylammonium chloride are mixed in a molar ratio of 20:1:2 and reacted under reflux at 80°C for 3 hours, with a nitrogen atmosphere maintained during the process. Then, an aqueous solution containing 40.0% sodium hydroxide by mass is added dropwise, and the reaction is continued for 1 hour. After the reaction is completed, the mixture is filtered, extracted, separated, and rotary evaporated in sequence, and then dried in a vacuum oven at 55~60°C to constant weight to obtain the final product.

2. The aluminum alloy of claim 1, wherein, The aluminum alloy is a 7-series aluminum alloy.

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