Passivation solution for hot-dip galvanized workpiece, and preparation method and use method thereof

Abstract

The invention relates to the field of coating materials, and discloses a passivation solution for a hot-dip galvanized workpiece as well as a preparation method and a use method.The passivation solution is prepared from organic pottery clay, titanium dioxide, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicon resin, a silane coupling agent, a coloring agent, filler, an auxiliary and water. The problem of light pollution in areas with high illumination intensity can be effectively solved, workpieces and vegetation in natural scenic areas are organically fused to form beautiful scenery lines, and the technical problems of high cost and weak corrosion resistance of green coatings caused by the fact that green towers are achieved by coating green paint at present can be effectively solved. And the pole tower is green, attractive and good in economic benefit.

Description

Technical Field

[0001] This invention relates to the field of coating materials, and more specifically to a passivation liquid, its preparation method, and its application method. Background Technology

[0002] In my country, traditional hot-dip galvanizing is used for corrosion protection of power transmission lines, resulting in a silvery-white appearance for the towers. While surface oxidation is slow in high-altitude environments, it easily causes light pollution under sunlight and blends poorly with the surrounding natural environment in areas with abundant vegetation. Therefore, research on color-coating for galvanized towers is needed. Domestic and international research on color-coating technologies for metal alloy layers focuses on colored galvanizing and VCI bimetallic coatings. Different processes exhibit significant differences in their corrosion protection mechanisms and effects. Colored galvanizing technology is still immature and remains in the laboratory stage; the corrosion protection performance of bimetallic coatings is difficult to guarantee.

[0003] Passivation treatment belongs to chemical conversion coating technology. It involves altering the surface state of a metal through chemical or electrochemical means, causing the electrode potential of the metal surface to jump in the positive direction, resulting in a corrosion-resistant passivated state and a certain degree of corrosion resistance. This thin film is called a passivation film. Passivation treatment of galvanized parts can significantly improve their corrosion resistance and also enhance their appearance, providing a better decorative effect. However, there is currently no existing technology for passivating outdoor galvanized iron towers to address the light pollution problem associated with this type of tower. Therefore, it is necessary to develop a passivation solution specifically designed for this type of outdoor galvanized iron tower. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a passivation solution and its application method. Zinc-plated parts passivated using the passivation solution provided by this invention exhibit low gloss, effectively solving the problem of light pollution in areas with strong sunlight.

[0005] To achieve the above objectives, the first aspect of the present invention provides a passivation solution for hot-dip galvanized workpieces, wherein the passivation solution comprises organic clay, titanium dioxide, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, silane coupling agent, colorant, filler, additives and water. Specifically, based on the total amount of the passivation solution, the concentration of the organic clay is 5-15 g / L, the concentration of the titanium dioxide is 1-13 g / L, the concentration of the ethylene-vinyl acetate copolymer emulsion is 100-220 g / L, the concentration of the waterborne epoxy silicone resin is 10-35 g / L, the concentration of the silane coupling agent is 0.2-3.5 g / L, and the concentration of the colorant is 10-60 g / L.

[0006] A second aspect of the present invention provides a method for preparing the passivation solution described in the first aspect of the present invention, wherein the preparation method includes: The titanium dioxide and silane coupling agent are mixed to obtain the modified material; The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, colorant, and filler are mixed evenly to obtain a mixture. Then, additives and water are added to the mixture to obtain a passivation solution.

[0007] A third aspect of the present invention provides a method for using the passivation solution described in the second aspect of the present invention, wherein the method comprises: immersing the workpiece to be treated in the passivation solution for 10-30 seconds, and then drying it.

[0008] The passivation solution provided by this invention can effectively solve the light pollution problem in areas with high light intensity. The workpiece can be organically integrated with the vegetation of natural scenic areas to form a beautiful landscape. In addition, it can also effectively reduce the current light pollution and achieve green and beautiful towers with good economic benefits.

[0009] The passivation solution provided by this invention can be prepared in batches at low cost, and its appearance can be military green, which blends very well with the outdoor environment. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the appearance of a military-green passivated steel plate component after galvanizing using the present invention. Detailed Implementation

[0011] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] The terms “first”, “second”, etc. are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. The objects distinguished by “first”, “second”, etc. are usually of the same class and the number of objects is not limited. For example, the first object can be one or more.

[0013] Furthermore, the term "and / or" in the specification and claims is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0014] In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0015] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0016] The first aspect of the present invention provides a passivation solution for hot-dip galvanized workpieces, wherein the passivation solution comprises organic clay, titanium dioxide, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, silane coupling agent, colorant, filler, additives and water; Specifically, based on the total amount of the passivation solution, the concentration of the organic clay is 5-15 g / L, the concentration of the titanium dioxide is 1-13 g / L, the concentration of the ethylene-vinyl acetate copolymer emulsion is 100-220 g / L, the concentration of the waterborne epoxy silicone resin is 10-35 g / L, the concentration of the silane coupling agent is 0.2-3.5 g / L, and the concentration of the colorant is 10-60 g / L.

[0017] Preferably, based on the total amount of the passivation solution, the concentration of the organic clay is 10-15 g / L, the concentration of the titanium dioxide is 8-12 g / L, the concentration of the ethylene-vinyl acetate copolymer emulsion is 180-220 g / L, the concentration of the waterborne epoxy silicone resin is 28-32 g / L, the concentration of the silane coupling agent is 2-3.5 g / L, and the concentration of the colorant is 45-55 g / L.

[0018] Based on the total amount of the passivation solution, the concentration of the organic clay can be 5 g / L, 7 g / L, 9 g / L, 11 g / L, 13, 15 g / L, or any value between any two of these numbers; the titanium dioxide is generally nano-titanium dioxide, and its concentration can be 1 g / L, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 13 g / L, or any value between any two of these numbers; the concentration of the ethylene-vinyl acetate copolymer emulsion can be 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 220 g / L, or any value between any two of these numbers. The concentration of the waterborne epoxy silicone resin can be any value, such as 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, or any value between any two of these values; the concentration of the silane coupling agent can be any value, such as 0.2 g / L, 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L, 3 g / L, 3.5 g / L, or any value between any two of these values; the concentration of the colorant can be any value, such as 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 55 g / L, 60 g / L, or any value between any two of these values.

[0019] Preferably, the colorant is iron oxide green or / or phthalocyanine green.

[0020] Preferably, the titanium dioxide is rutile. Rutile titanium dioxide has a more stable structure, lower photocatalytic activity on its surface, and is less likely to react with ultraviolet light, moisture, and chemicals in the air, thus providing better protection for the substrate and making it particularly suitable for outdoor use.

[0021] Preferably, the additives include defoamers, penetrants, neutralizers, drying agents, dispersants, and leveling agents.

[0022] Based on the total amount of the passivation solution, the concentration of the defoamer is 0.3-2 mL / L, the concentration of the penetrant is 0.5-3 mL / L, the concentration of the neutralizer is 3-15 g / L, the concentration of the drying agent is 12-25 g / L, the concentration of the dispersant is 1-5 g / L, and the concentration of the leveling agent is 3-15 g / L.

[0023] Preferably, based on the total amount of the passivation solution, the concentration of the defoamer is 0.3-0.8 mL / L, the concentration of the penetrant is 0.5-1.5 mL / L, the concentration of the neutralizer is 3-8 g / L, the concentration of the drying agent is 12-20 g / L, the concentration of the dispersant is 1-3 g / L, and the concentration of the leveling agent is 3-8 g / L.

[0024] The concentration of the defoamer can be 0.3 mL / L, 0.5 mL / L, 0.8 mL / L, 1 mL / L, 1.5 mL / L, 2 mL / L, or any value between any two of these numbers.

[0025] The concentration of the penetrant can be 0.5 mL / L, 1 mL / L, 1.5 mL / L, 2 mL / L, 2.5 mL / L, 3 mL / L, or any value between any two of these numbers.

[0026] The role of the neutralizing agent is to ensure that the resin system is a stable and workable water-based system. The concentration of the neutralizing agent can be 3g / L, 5g / L, 8g / L, 10g / L, 12g / L, 15g / L, or any value between any two of these numbers.

[0027] The role of the drier is to ensure the rapid formation of the organosilicon network, which is enriched on the coating surface to provide long-lasting weather resistance, water repellency and surface feel. The concentration of the drier can be 12 g / L, 14 g / L, 16 g / L, 18 g / L, 20 g / L, 25 g / L and any value between any two of them.

[0028] The role of dispersants is to prevent colorants and fillers from settling and clumping, and to ensure that the color and performance of the formulation are uniform and stable. Their concentration can be 1 g / L, 2 g / L, 3 g / L, 5 g / L, or any value between any two of them.

[0029] The function of leveling agents is to effectively reduce surface tension, provide excellent leveling, wetting and anti-cratering capabilities, and usually also bring slip and scratch resistance. Their concentration can be 3g / L, 5g / L, 8g / L, 10g / L, 12g / L, 15g / L and any value between any two of them.

[0030] This application does not specify the specific types of defoamers, penetrants, neutralizers, driers, dispersants, and leveling agents; any commonly used in the field may be used. For example, the defoamer may be JFC, the penetrant may be (DMEA), the neutralizer may be a water-based resin drier, the leveling agent may be modified polydimethylsiloxane, and the dispersant may be sodium polyacrylate.

[0031] Preferably, based on the total amount of the ethylene-vinyl acetate copolymer emulsion, its solid content is 50-60 wt.%, and the number average molecular weight of the ethylene-vinyl acetate copolymer in the ethylene-vinyl acetate copolymer emulsion is 50,000-60,000 g / mol. The number average molecular weight of the ethylene-vinyl acetate copolymer affects the film-forming properties of the passivation solution, and thus affects the corrosion resistance, wear resistance, and other properties of the passivation film. The zinc-plated workpiece treated with the passivation solution prepared in this application exhibits excellent corrosion resistance.

[0032] Preferably, the filler is calcium carbonate, and the concentration of calcium carbonate is 50-100 g / L based on the total amount of the passivation solution. Calcium carbonate is a rigid particle that is uniformly dispersed in the resin crosslinking network, effectively improving the hardness and scratch resistance of the coating. It can also withstand a certain amount of friction, thus enhancing the wear life of the coating. The concentration of calcium carbonate can be 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, or any value between any two of these values.

[0033] The passivation solution provided by this invention does not contain any heavy metal elements such as chromium ions (Cr), cadmium (Cd), lead (Pb), and mercury (Hg), and at the same time eliminates the introduction of persistent organic pollutants such as polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs), thereby eliminating the potential pollution risks to the environment caused by the passivation process at the source and making it environmentally friendly.

[0034] A second aspect of the present invention provides a method for preparing the passivation solution described in the first aspect of the present invention, wherein the preparation method includes: The titanium dioxide and silane coupling agent are mixed to obtain the modified material; The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, colorant, and filler are mixed evenly to obtain a mixture. Then, additives and water are added to the mixture to obtain a passivation solution.

[0035] Preferably, the step of adding additives and water includes: adding a neutralizer, a dispersant, and a leveling agent to the mixture, mixing it evenly, and then adding the defoamer, penetrant, drier, and water.

[0036] In this application, when preparing the passivation solution, nano-titanium dioxide is first mixed with a silane coupling agent to modify the nano-titanium dioxide. Through the "bridging" effect of the silane coupling agent, the functional groups (such as alkoxy groups) at one end will chemically react or firmly bind with the hydroxyl groups (-OH) on the surface of the nano-titanium dioxide, while the organic functional groups at the other end are compatible with the subsequently added organic matrix (such as resin, plastic, coating), thereby enhancing the synergistic effect of the physical barrier and chemical corrosion protection of the passivation film.

[0037] A third aspect of the present invention provides a method for using the passivation solution described in the second aspect of the present invention, wherein the method comprises: immersing the workpiece to be treated in the passivation solution for 10-30 seconds, and then drying it.

[0038] This invention does not have special requirements for the drying method; commonly used drying methods in the field, such as air drying and oven drying, are all acceptable. The passivation solution provided by this invention does not require high-temperature treatment during use and has a short treatment time. After passivation treatment, the workpiece surface forms a conversion film layer with a natural green tone and low gloss (matte) characteristics, which significantly enhances the visual harmony between the workpiece (such as an overhead power transmission line tower) and the surrounding natural landscape. Especially in areas with high light intensity, its low reflectivity effectively suppresses light pollution and enhances its practical value.

[0039] The method of use provided by this invention is simple in process, requires widely available and easily accessible raw materials, and has significant cost-effectiveness. Its ease of operation lays a solid industrial foundation for its widespread application in the field of galvanized metal protection.

[0040] The present invention will be described in detail below through examples. Unless otherwise specified, all reagents or instruments used in the following examples are commercially available conventional products. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply.

[0041] GU values ​​are tested according to the ISO 2813 method; The neutral salt spray test was conducted using the ISO 3768 method.

[0042] The workpiece substrate is a steel plate with a thickness of 5mm, a length of 12cm and a width of 8cm.

[0043] Nano titanium dioxide (rutile type), particle size 50nm; Ethylene-vinyl acetate copolymer emulsion, solid content 54.5 wt.%, wherein the number average molecular weight of the ethylene-vinyl acetate copolymer is 50,000-60,000 / mol, purchased from Sichuan Weihua Chemical Co., Ltd., model VAE705; The waterborne epoxy silicone resin was purchased from Shenzhen Weiteli Environmental Protection Materials Co., Ltd., model V2401. Silane coupling agent, purchased from Sinopharm Group, model KH-570; Polyether-modified silicone defoamer, purchased from the company, model D-001; Penetrant, purchased from Nantong Dexin Chemical Co., Ltd., model JFC; Dimethylethanolamine (DMEA) was purchased from Maclean's, analytical grade. The drying agent, model DMP-30, was purchased from Shandong Maofa Chemical Co., Ltd. Modified polydimethylsiloxane, purchased from Guangdong Zhongtai Lianhua New Materials Co., Ltd., model AG-217; Sodium polyacrylate, purchased from Guangdong Zhongtai Lianhua New Materials Co., Ltd., model AG-22.

[0044] Example 1 S1. Prepare raw materials according to 1L passivation solution. The components and contents are as follows: 5g organic clay, 100g ethylene-vinyl acetate copolymer emulsion (VAE705 emulsion), 1g nano titanium dioxide (rutile type), 50g calcium carbonate; 10g waterborne epoxy silicone resin, 0.25g silane coupling agent, 10, 0.5mL, penetrant (JFC) 1mL, neutralizing agent dimethylethanolamine (DMEA) 5g, drying agent 15g, dispersant sodium polyacrylate 2g, leveling agent modified polydimethylsiloxane 5g, and the balance is deionized water.

[0045] S2, mix nano-titanium dioxide (rutile type) and silane coupling agent for 1 hour to obtain modified material; S3. The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, iron oxide green, and calcium carbonate are mixed evenly to obtain a mixture. Then, the polyether modified silicone defoamer, penetrant, neutralizing agent dimethylethanolamine (DMEA), drying agent, dispersant sodium polyacrylate, and leveling agent modified polydimethylsiloxane are added to the mixture, and deionized water is added to make up to 1L to obtain a passivation solution.

[0046] Example 2 S1. Prepare raw materials according to 1L passivation solution. The components and contents are as follows: 7g organic clay, 120g ethylene-vinyl acetate copolymer emulsion (VAE705 emulsion), 4g nano titanium dioxide (rutile type), 60g calcium carbonate; 15g waterborne epoxy silicone resin, 1g silane coupling agent, 20g iron oxide green, 0.6mL polyether modified silicone defoamer, 1.2mL penetrant (JFC), 6g neutralizing agent dimethylethanolamine (DMEA), 18g drying agent, 2.5g dispersant sodium polyacrylate, 7g leveling agent modified polydimethylsiloxane, and the balance is deionized water.

[0047] S2, mix nano-titanium dioxide (rutile type) and silane coupling agent for 1 hour to obtain modified material; S3. The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, iron oxide green, and calcium carbonate are mixed evenly to obtain a mixture. Then, the polyether modified silicone defoamer, penetrant (JFC), neutralizer dimethylethanolamine (DMEA), drying agent, dispersant sodium polyacrylate, and leveling agent modified polydimethylsiloxane are added to the mixture, and deionized water is added to make up to 1L to obtain a passivation solution.

[0048] Example 3 S1. Prepare raw materials according to 1L passivation solution. The components and contents are as follows: 9g organic clay, 150g ethylene-vinyl acetate copolymer emulsion (VAE705 emulsion), 6g nano titanium dioxide (rutile type), 75g calcium carbonate; 20g waterborne epoxy silicone resin, 1.5g silane coupling agent, 30g iron oxide green, 0.8mL polyether modified silicone defoamer, 1.5mL penetrant (JFC), 8g neutralizing agent dimethylethanolamine (DMEA), 18g drying agent, 3g dispersant sodium polyacrylate, 8g leveling agent modified polydimethylsiloxane, and the balance is deionized water.

[0049] S2, mix nano-titanium dioxide (rutile type) and silane coupling agent to obtain modified material; S3. The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, iron oxide green, and calcium carbonate are mixed evenly to obtain a mixture. Then, the polyether modified silicone defoamer, penetrant (JFC), neutralizer dimethylethanolamine (DMEA), drying agent, dispersant sodium polyacrylate, and leveling agent modified polydimethylsiloxane are added to the mixture, and deionized water is added to make up to 1L to obtain a passivation solution.

[0050] Example 4 S1. Prepare raw materials according to 1L passivation solution. The components and contents are as follows: 11g organic clay, 180g ethylene-vinyl acetate copolymer emulsion (VAE705 emulsion), 8g nano titanium dioxide (rutile type), 90g calcium carbonate; 25g waterborne epoxy silicone resin, 2g silane coupling agent, 40g iron oxide green, 1mL polyether modified silicone defoamer, 2mL penetrant (JFC), 10g neutralizing agent dimethylethanolamine (DMEA), 20g drying agent, 3.5g dispersant sodium polyacrylate, 10g leveling agent modified polydimethylsiloxane, and the balance is deionized water.

[0051] S2, mix nano-titanium dioxide (rutile type) and silane coupling agent to obtain modified material; S3. The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, iron oxide green, and calcium carbonate are mixed evenly to obtain a mixture. Then, the polyether modified silicone defoamer, penetrant (JFC), neutralizer dimethylethanolamine (DMEA), drying agent, dispersant sodium polyacrylate, and leveling agent modified polydimethylsiloxane are added to the mixture, and deionized water is added to make up to 1L to obtain a passivation solution.

[0052] Example 5 S1. Prepare raw materials according to 1L passivation solution. The components and contents are as follows: 13g organic clay, 200g ethylene-vinyl acetate copolymer emulsion (VAE705 emulsion), 10g nano titanium dioxide (rutile type), 100g calcium carbonate; 30g waterborne epoxy silicone resin, 2.5g silane coupling agent, 50g iron oxide green, 1.5mL polyether modified silicone defoamer, 3mL penetrant (JFC), 12g neutralizing agent dimethylethanolamine (DMEA), 21g drying agent, 4g dispersant sodium polyacrylate, 12g leveling agent modified polydimethylsiloxane, and the balance is deionized water.

[0053] S2, mix nano-titanium dioxide (rutile type) and silane coupling agent to obtain modified material; S3. The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, iron oxide green, and calcium carbonate are mixed evenly to obtain a mixture. Then, the polyether modified silicone defoamer, penetrant (JFC), neutralizer dimethylethanolamine (DMEA), drying agent, dispersant sodium polyacrylate, and leveling agent modified polydimethylsiloxane are added to the mixture, and deionized water is added to make up to 1L to obtain a passivation solution.

[0054] Test case Prepare multiple Q355 steel plates to be processed, and then hot-dip galvanize them according to the conventional galvanizing process. The specific process flow is as follows: The Q355 steel plate to be processed is first pickled to remove rust, then washed with water, then coated with flux, then dried, then hot-dip galvanized, and finally cooled to obtain a galvanized steel plate. The specific operations in the hot-dip galvanizing process can be carried out using methods commonly used in the field, which are existing technologies and will not be described in detail here.

[0055] Each galvanized steel sheet was immersed in the passivation solution prepared in Examples 1-5, passivated for 10 seconds, and then dried to obtain the passivated galvanized workpiece.

[0056] The corrosion resistance and gloss of the passivated galvanized workpieces were tested respectively, and the results are shown in Table 1.

[0057] Table 1

[0058] As can be seen from the table, the galvanized workpieces treated with the passivation solution provided by the present invention have excellent corrosion resistance and low gloss (matte, low GU value), making them very suitable for outdoor use under strong sunlight. In particular, the passivation solution prepared in Example 5, after 108 hours of neutral salt spray test, showed a white rust area percentage of less than 5% and a GU value of only about 11.

[0059] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and all fall within the protection scope of the present invention. Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A passivation solution, characterized in that, The passivation solution comprises organic clay, titanium dioxide, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, silane coupling agent, colorant, filler, additives and water; Specifically, based on the total amount of the passivation solution, the concentration of the organic clay is 5-15 g / L, the concentration of the titanium dioxide is 1-13 g / L, the concentration of the ethylene-vinyl acetate copolymer emulsion is 100-220 g / L, the concentration of the waterborne epoxy silicone resin is 10-35 g / L, the concentration of the silane coupling agent is 0.2-3.5 g / L, and the concentration of the colorant is 10-60 g / L.

2. The passivation solution according to claim 1, wherein, Based on the total amount of the passivation solution, the concentration of the organic clay is 10-15 g / L, the concentration of the titanium dioxide is 8-12 g / L, the concentration of the ethylene-vinyl acetate copolymer emulsion is 180-220 g / L, the concentration of the waterborne epoxy silicone resin is 28-32 g / L, the concentration of the silane coupling agent is 2-3.5 g / L, and the concentration of the colorant is 45-55 g / L.

3. The passivation solution according to claim 1 or 2, wherein, The additives include defoamers, penetrants, neutralizers, drying agents, dispersants, and leveling agents.

4. The passivation solution according to claim 3, wherein, Based on the total amount of the passivation solution, the concentration of the defoamer is 0.3-2 mL / L, the concentration of the penetrant is 0.5-3 mL / L, the concentration of the neutralizer is 3-15 g / L, the concentration of the drying agent is 12-25 g / L, the concentration of the dispersant is 1-5 g / L, and the concentration of the leveling agent is 3-15 g / L. Preferably, based on the total amount of the passivation solution, the concentration of the defoamer is 0.3-0.8 mL / L, the concentration of the penetrant is 0.5-1.5 mL / L, the concentration of the neutralizer is 3-8 g / L, the concentration of the drying agent is 12-20 g / L, the concentration of the dispersant is 1-3 g / L, and the concentration of the leveling agent is 3-8 g / L.

5. The passivation solution according to claim 1 or 2, wherein, Based on the total amount of the ethylene-vinyl acetate copolymer emulsion, its solid content is 50-60 wt.%, and the number average molecular weight of the ethylene-vinyl acetate copolymer in the ethylene-vinyl acetate copolymer emulsion is 50,000-60,000 g / mol.

6. The passivation solution according to claim 5, wherein, The filler is calcium carbonate, and the concentration of calcium carbonate is 50-100 g / L based on the total amount of the passivation solution.

7. The passivation solution according to claim 1 or 2, wherein, The colorant is iron oxide green and / or phthalocyanine green; and / or, The titanium dioxide is rutile.

8. A method for preparing the passivation solution according to any one of claims 1-7, characterized in that, The preparation method includes: The titanium dioxide and silane coupling agent are mixed to obtain the modified material; The modified material, organic clay, ethylene-vinyl acetate copolymer emulsion, waterborne epoxy silicone resin, colorant, and filler are mixed evenly to obtain a mixture. Then, additives and water are added to the mixture to obtain a passivation solution.

9. The preparation method according to claim 8, wherein, The step of adding additives and water includes: adding neutralizer, dispersant, and leveling agent to the mixture, mixing well, and then adding defoamer, penetrant, drying agent, and water.

10. A method of using the passivation solution according to claim 8 or 9, characterized in that, The method of use includes immersing the workpiece to be treated in the passivation solution for 10-30 seconds, and then drying it.

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