Surface sealing coating for antibacterial stainless steel colored film and sealing treatment method thereof

Abstract

The invention belongs to the technical field of metal surface treatment, and discloses a surface sealing coating for an antibacterial stainless steel coloring film and a sealing treatment method of the surface sealing coating. The surface sealing coating comprises the following raw materials in parts by weight: 30-50 parts of matrix resin, 15-25 parts of corrosion inhibition filler, 5-10 parts of an adhesion promoter, 20-30 parts of a solvent, 2-5 parts of an auxiliary agent and 5-20 parts of an organosilicon quaternary ammonium salt antibacterial agent. Wherein the matrix resin is epoxy modified acrylic resin; the corrosion inhibition filler is selected from at least one of modified strontium aluminum phosphate and nano silicon dioxide. According to the invention, the epoxy modified acrylic resin is used as matrix resin, and has high adhesiveness of epoxy and weather resistance of acrylic acid; environment-friendly corrosion inhibition filler strontium aluminum phosphate is compounded with nano silicon dioxide, so that corrosion inhibition ions are released when the coating is damaged, and pitting corrosion is inhibited; meanwhile, by slowly releasing the organosilicon quaternary ammonium salt compound, adhesion and breeding of bacteria are effectively hindered.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal surface treatment, and particularly relates to a surface sealing coating for antibacterial stainless steel coloring film and a sealing treatment method thereof. BACKGROUND

[0002] Stainless steel coloring technology is a mature special surface technology with wide application prospect. After chemical coloring or electrolytic coloring, the surface of stainless steel forms colorful coloring film of different colors. However, the oxidation film obtained by chemical coloring or electrolytic coloring has the defects of poor wear resistance and poor stain resistance. In order to make the coloring film bright in color and excellent in performance, sealing treatment is required. The existing technology usually adopts electrolytic sealing and hot water sealing treatment method, or double sealing method, which can effectively improve the wear resistance and stain resistance of the coloring film. However, the stainless steel coloring film sealed by such methods only blocks the micropores in the stainless steel coloring layer, and does not reduce the color of the stainless steel coloring layer due to the absorption of pollutants by the micropores in use. However, it does not have antibacterial function. SUMMARY

[0003] In view of the above problems existing in the prior art, the purpose of the present application is to provide a surface sealing coating for antibacterial stainless steel coloring film and a sealing treatment method thereof.

[0004] To solve the above problems, the present application provides the following technical scheme: In a first aspect, the present application provides a surface sealing coating for antibacterial stainless steel coloring film, which comprises the following raw materials in parts by weight: 30-50 parts of base resin, 15-25 parts of corrosion inhibition filler, 5-10 parts of adhesion promoter, 20-30 parts of solvent, 2-5 parts of auxiliary agent and 5-20 parts of organosilicon quaternary ammonium salt antibacterial agent.

[0005] In an embodiment of the present application, the base resin is an epoxy modified acrylic resin.

[0006] In an embodiment of the present application, the epoxy modified acrylic resin is prepared by graft copolymerization of epoxy resin, methyl methacrylate and acrylic acid.

[0007] In an embodiment of the present application, the epoxy resin is selected from epoxy resin E-51.

[0008] In an embodiment of the present application, the residual amount of epoxy groups of the epoxy modified acrylic resin is ≤5%.

[0009] In an embodiment of the present application, the corrosion inhibition filler is selected from at least one of modified strontium aluminum phosphate and nano silicon dioxide.

[0010] In an embodiment of the present application, the corrosion inhibitor filler is selected from a compound of modified strontium aluminum phosphate and nano-silica.

[0011] In an embodiment of the present application, the compound ratio of the modified strontium aluminum phosphate and nano-silica is 4:1.

[0012] In an embodiment of the present application, the strontium aluminum phosphate is surface treated by a silane coupling agent.

[0013] In an embodiment of the present application, the silane coupling agent is selected from KH-560.

[0014] In an embodiment of the present application, the D50 of the modified strontium aluminum phosphate is ≤3 μm.

[0015] In an embodiment of the present application, the particle size of the nano-silica is 10-30 nm.

[0016] In an embodiment of the present application, the particle size of the nano-silica is 20 nm.

[0017] In an embodiment of the present application, the adhesion promoter is selected from a compound of γ-glycidoxypropyltrimethoxysilane and titanate coupling agent.

[0018] In an embodiment of the present application, the compound ratio of the γ-glycidoxypropyltrimethoxysilane and titanate coupling agent is 2:1.

[0019] In an embodiment of the present application, the titanate coupling agent is selected from TMC-201.

[0020] In an embodiment of the present application, the solvent is selected from at least one of propylene glycol methyl ether acetate, dimethylbenzene.

[0021] In an embodiment of the present application, the solvent is selected from a compound of propylene glycol methyl ether acetate and dimethylbenzene.

[0022] In an embodiment of the present application, the compound ratio of the propylene glycol methyl ether acetate and dimethylbenzene is 3:1.

[0023] In an embodiment of the present application, the boiling point of the solvent is 120-160°C.

[0024] In an embodiment of the present application, the volatilization rate of the solvent is 0.6 times that of n-butyl acetate.

[0025] In an embodiment of the present application, the solvent used is an environmentally friendly low-volatility solvent.

[0026] In an embodiment of the present application, the auxiliary agent is selected from at least one of a dispersing agent, a defoaming agent, a leveling agent.

[0027] In one embodiment of this application, the dispersant is selected from modified polycarboxylate polymers.

[0028] In one embodiment of this application, the dispersant is selected from BYK-190.

[0029] In one embodiment of this application, the weight ratio of the dispersant to nano-silica is 1:5.

[0030] In one embodiment of this application, the defoamer is selected from polyether-modified siloxane.

[0031] In one embodiment of this application, the defoamer is selected from BYK-024.

[0032] In one embodiment of this application, the leveling agent is selected from fluorinated modified acrylates.

[0033] In one embodiment of this application, the leveling agent is selected from TEGO Glide 410.

[0034] In one embodiment of this application, the weight ratio of defoamer to leveling agent is 1:1.5-4.

[0035] In one embodiment of this application, the organosilicon quaternary ammonium salt antibacterial agent is selected from at least one of 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride and 3-(triethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0036] Secondly, this application provides a method for preparing a surface sealing coating for an antibacterial stainless steel colored film, comprising the following steps: S1. Add the matrix resin and solvent to the reaction vessel and stir to disperse; S2. Add corrosion inhibitor and adhesion promoter to the mixed solution obtained in S1, and shear and disperse until the fineness is ≤20μm; S3. Add dispersant, leveling agent and defoamer to the mixed solution obtained in S2 stepwise to disperse and defoam, and obtain the initial coating. S4. Add the organosilicon quaternary ammonium salt antibacterial agent to the initial coating and stir evenly to obtain the surface sealing coating of the antibacterial stainless steel colored film.

[0037] Thirdly, this application provides a method for sealing treatment using a surface sealing coating of antibacterial stainless steel colored film, comprising the following steps: The surface sealing coating is brushed onto the surface of the stainless steel colored film and baked at 80-100℃ for 20-40 minutes to form a film.

[0038] In one embodiment of this application, the baking temperature is 90°C.

[0039] In one embodiment of this application, the baking time is 30 minutes.

[0040] In one embodiment of this application, the surface roughness Ra of the membrane is ≤0.2μm.

[0041] In one embodiment of this application, the thickness of the membrane is 30-50 μm.

[0042] Compared with the prior art, the present invention has the following beneficial effects: (1) This application slowly releases organosilicon quaternary ammonium salt compounds, which adsorb onto the surface of bacteria with negative charges, disrupting their electrolyte balance and causing the bacteria to die due to cell wall damage, thereby hindering bacterial attachment and growth. (2) This application uses epoxy-modified acrylic resin as the matrix resin, which combines the high adhesion of epoxy and the weather resistance of acrylic. (3) This application uses environmentally friendly corrosion-inhibiting filler strontium aluminum phosphate combined with nano silica to release corrosion-inhibiting ions when the coating is damaged, thereby inhibiting pitting corrosion; (4) This application adopts a low-temperature curing process, which is simple to construct, and the surface sealing coating of the antibacterial stainless steel coloring film will not cover the original color of the stainless steel coloring film. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0045] The epoxy-modified acrylic resin used in the following examples is obtained by graft copolymerization of epoxy resin E-51 with methyl methacrylate (MMA) and acrylic acid (AA), with an epoxy group residual rate of ≤5%, to ensure a balance between weather resistance and adhesion.

[0046] The modified strontium aluminum phosphate (D50≤3μm) used in the following examples was prepared by surface treatment of strontium aluminum phosphate with silane coupling agent KH-560.

[0047] The nano-silica used in the following examples has a particle size of 10-30 nm, preferably 20 nm. Example 1

[0048] A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 40 parts epoxy-modified acrylic resin, 16 parts modified strontium aluminum phosphate, 4 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, 2.4 parts TEGO Glide 410, and 7 parts 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0049] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0050] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm. Example 2

[0051] A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 45 parts epoxy-modified acrylic resin, 12 parts modified strontium aluminum phosphate, 3 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, 2.4 parts TEGO Glide 410, and 7 parts 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0052] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0053] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm. Example 3

[0054] A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 35 parts epoxy-modified acrylic resin, 20 parts modified strontium aluminum phosphate, 5 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, 2.4 parts TEGO Glide 410, and 7 parts 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0055] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0056] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0057] Comparative Example 1 A surface sealing coating, by weight fraction, comprises the following raw materials: The composition includes 47 parts epoxy-modified acrylic resin, 16 parts modified strontium aluminum phosphate, 4 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, and 2.4 parts TEGO Glide 410.

[0058] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to a reaction vessel according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain a surface sealing coating.

[0059] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0060] Comparative Example 2 A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 40 parts epoxy-modified acrylic resin, 10 parts modified strontium aluminum phosphate, 10 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, 2.4 parts TEGO Glide 410, and 7 parts 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0061] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0062] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0063] Comparative Example 3 A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 44 parts of epoxy-modified acrylic resin, 16 parts of modified strontium aluminum phosphate, 6 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of TMC-201, 15 parts of propylene glycol methyl ether acetate, 5 parts of xylene, 0.8 parts of BYK-190, 0.8 parts of BYK-024, 2.4 parts of TEGO Glide 410, and 7 parts of 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0064] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0065] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0066] Comparative Example 4 A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 40 parts of pure acrylic resin, 16 parts of modified strontium aluminum phosphate, 4 parts of nano silica, 6 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts of TMC-201, 15 parts of propylene glycol methyl ether acetate, 5 parts of xylene, 0.8 parts of BYK-190, 0.8 parts of BYK-024, 2.4 parts of TEGO Glide 410, and 7 parts of 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0067] Its preparation method is as follows: Pure acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0068] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0069] Comparative Example 5 A surface sealing coating for an antibacterial stainless steel colored film, comprising the following raw materials by weight fraction: The composition includes 40 parts epoxy-modified acrylic resin, 4 parts modified strontium aluminum phosphate, 16 parts nano silica, 6 parts γ-glycidyl etheroxypropyltrimethoxysilane, 3 parts TMC-201, 15 parts propylene glycol methyl ether acetate, 5 parts xylene, 0.8 parts BYK-190, 0.8 parts BYK-024, 2.4 parts TEGO Glide 410, and 7 parts 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride.

[0070] Its preparation method is as follows: Epoxy-modified acrylic resin, propylene glycol methyl ether acetate, and xylene were added to the reactor according to the weight ratio and stirred to disperse. Then, modified strontium aluminum phosphate, nano silica, γ-glycidyl etheroxypropyltrimethoxysilane, and TMC-201 were added and dispersed at high speed until the fineness was ≤20μm. Then, BYK-190, TEGO Glide 410, and BYK-024 were added stepwise. First, the mixture was dispersed at high speed to form a uniform system, and then degassed at low speed to obtain the initial coating. Finally, 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride was added to the initial coating and stirred evenly.

[0071] A sealing coating is brushed onto the surface of the stainless steel colored film and baked at 90°C for 30 minutes to form a film, ensuring that the sealing film is free of pinhole defects and that the surface roughness Ra of the sealing film is ≤0.2μm.

[0072] The sealing films prepared in the above examples and comparative examples (with a thickness of 40 μm) were subjected to the following performance tests: The hardness of the film was tested according to GB / T6739-1996 "Determination of Hardness of Coatings by Pencil Test"; The adhesion of the film was tested according to GB / T 9286-1998 "Cross-cut test of paint and varnish films"; The impact resistance of the film was tested according to GB / T 4893.9-2013 "Tests on the physical and chemical properties of coatings on furniture surfaces - Part 9: Test of impact resistance". The antibacterial properties of the membrane against Escherichia coli were tested according to GB / T 21510-2008 "Test Method for Antibacterial Properties of Nano-Inorganic Materials"; Corrosion resistance tests were conducted in accordance with GB / T 2423.17-2024 "Environmental Testing - Part 2: Test Methods - Test Ka: Salt Spray".

[0073] The specific test results are shown in Table 1.

[0074] Table 1 ; As shown in Table 1, compared with Comparative Examples 2-5, the epoxy-modified acrylic resin and modified strontium aluminum phosphate / nano silica composites provided excellent adhesion, hardness, and impact resistance. The epoxy groups in the epoxy-modified acrylic resin can form chemical bonds with the hydroxyl groups on the metal surface, and the polar groups in the epoxy-modified acrylic resin can form dipole-dipole interactions with the metal surface, improving adhesion. The acrylic resin portion also provides good weather resistance. The epoxy-modified acrylic resin can also form strong interfacial bonds with the filler, improving hardness. Nano silica makes a significant contribution to adhesion, hardness, impact resistance, and corrosion resistance, but needs to be added in appropriate amounts.

[0075] Compared with Examples 1-3, Comparative Examples 1 and 4, and Comparative Examples 2, 3, and 5, the modified strontium aluminum phosphate to nano-silica weight ratio of 4:1 exhibits better corrosion resistance. Comparing Example 1 with Comparative Example 4, it is evident that epoxy-modified acrylic resin has better corrosion resistance than pure acrylic resin. The corrosion resistance of Example 2 is lower than that of Example 1, indicating that an excessively high matrix resin content and an excessively low corrosion inhibitor content are detrimental to improving corrosion resistance. Compared with Comparative Example 1, Example 1 has zero antibacterial activity, but other properties are essentially the same as in Example 1, indicating that the antibacterial agent has little impact on other properties.

[0076] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A surface sealing coating for an antibacterial stainless steel colored film, characterized in that, By weight, it includes the following ingredients: 30-50 parts matrix resin, 15-25 parts corrosion inhibitor filler, 5-10 parts adhesion promoter, 20-30 parts solvent, 2-5 parts additives and 5-20 parts organosilicon quaternary ammonium salt antibacterial agent; The matrix resin is an epoxy-modified acrylic resin; The corrosion inhibitor filler is selected from at least one of modified strontium aluminum phosphate and nano silica.

2. The surface sealing coating for the antibacterial stainless steel colored film according to claim 1, characterized in that, The adhesion promoter is selected from a compound of γ-glycidyl etheroxypropyltrimethoxysilane and titanate coupling agent; The solvent is selected from at least one of propylene glycol methyl ether acetate and xylene; The additive is selected from at least one of dispersants, defoamers, and leveling agents.

3. The surface sealing coating for the antibacterial stainless steel colored film according to claim 1, characterized in that, The epoxy-modified acrylic resin is obtained by graft copolymerization of epoxy resin with methyl methacrylate and acrylic acid, and the residual amount of epoxy groups in the epoxy-modified acrylic resin is ≤5%.

4. The surface sealing coating for the antibacterial stainless steel colored film according to claim 1, characterized in that, The corrosion inhibitor filler is selected from a compound of modified strontium aluminum phosphate and nano silica; The ratio of the modified strontium aluminum phosphate to nano silica is 4:1; The strontium aluminum phosphate is surface-treated with a silane coupling agent.

5. The surface sealing coating for the antibacterial stainless steel colored film according to claim 2, characterized in that, The ratio of the γ-glycidyl etheroxypropyltrimethoxysilane to the titanate coupling agent is 2:1; The titanate coupling agent is selected from TMC-201.

6. The surface sealing coating for the antibacterial stainless steel colored film according to claim 2, characterized in that, The solvent is selected from a compound of propylene glycol methyl ether acetate and xylene; The ratio of propylene glycol methyl ether acetate to xylene is 3:

1.

7. The surface sealing coating for the antibacterial stainless steel colored film according to claim 6, characterized in that, The solvent has a boiling point of 120-160℃; The solvent has an evaporation rate 0.6 times that of n-butyl acetate.

8. A method for preparing the surface sealing coating of the antibacterial stainless steel colored film according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Add the matrix resin and solvent to the reaction vessel and stir to disperse; S2. Add corrosion inhibitor and adhesion promoter to the mixed solution obtained in S1, and shear and disperse until the fineness is ≤20μm; S3. Add dispersant, leveling agent and defoamer to the mixed solution obtained in S2 stepwise to disperse and defoam, and obtain the initial coating. S4. Add the organosilicon quaternary ammonium salt antibacterial agent to the initial coating and stir evenly to obtain the surface sealing coating of the antibacterial stainless steel colored film.

9. A method for sealing the surface of an antibacterial stainless steel colored film using a surface-sealing coating according to any one of claims 1-7, characterized in that, Includes the following steps: The surface sealing coating is brushed onto the surface of the stainless steel colored film and baked at 80-100℃ for 20-40 minutes to form a film.

10. A method for sealing the surface of the antibacterial stainless steel colored film according to claim 9, characterized in that, The baking temperature is 90℃; the baking time is 30 minutes; and the surface roughness Ra of the membrane is ≤0.2μm.