Environment-friendly phosphorus-free and heavy metal-free ceramic modifier and preparation method thereof

Abstract

This invention relates to the field of chemical technology, specifically to an environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method. The environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method include the following steps: modifying a silane coupling agent by adding tetradecyltrimethylammonium bromide; hydrolyzing the modified silane coupling agent; cooling the reaction vessel and adding a phosphorus-free metal surface treatment agent and citric acid; pressurizing and cooling while adjusting the pH value; adding EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mixing, and restoring to room temperature and pressure. This invention, by replacing the metal surface treatment agent component in the ceramic coating agent from a phosphating agent to phosphorus-free hexafluorozirconic acid or fluorozirconic acid, achieves the passivation effect of the ceramic coating agent without adding phosphorus and heavy metals, thus protecting the environment, reducing pollution, and achieving an environmentally friendly and green effect.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to an environmentally friendly, phosphorus-free, and heavy metal-free ceramic agent and its preparation method. Background Technology

[0002] With the development of industrial manufacturing, metal pipes or sheets are frequently used in various fields. However, metal surfaces are prone to corrosion if not maintained. Therefore, it is necessary to treat metal surfaces exposed to the external environment. Existing metal surface treatment processes generally involve coating, with different effects depending on the coating material, such as heat resistance, corrosion resistance, and antistatic properties. Current processes for coating corrosion-resistant metal surfaces often involve applying a passivating agent to the metal surface to passivate it and achieve corrosion resistance.

[0003] Traditional ceramic coating agents are mostly phosphating agents. While phosphating agent production technology is mature, it easily causes phosphorus pollution and contains significant amounts of metals such as chromium, nickel, and zinc. Industrially, ten metals are classified as heavy metals: copper, lead, zinc, tin, nickel, cobalt, antimony, mercury, cadmium, and bismuth. If these heavy metals from phosphating agents are directly released into the land without treatment, they will cause widespread soil pollution. Furthermore, if the metal materials coated with phosphating agents are not properly recycled and are discarded into the natural environment, they will cause significant pollution. Therefore, an environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent is needed to solve these problems. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide an environmentally friendly, phosphorus-free, and heavy metal-free ceramic agent and its preparation method.

[0005] An environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method, specifically including the following steps:

[0006] S1: Modify the silane coupling agent by adding tetradecyltrimethylammonium bromide.

[0007] Add the silane coupling agent to a stirred container, then add sufficient tetradecyltrimethylammonium bromide to a dropper. Install the dropper on the stirred container, start the stirred container, and stir the silane coupling agent at a low speed. At the same time, add tetradecyltrimethylammonium bromide to the silane coupling agent through the dropper. Then turn off the dropper to obtain a mixed solution. Under stirring, add anhydrous ethanol to the mixed solution, then heat the stirred container in a water bath and maintain a constant temperature for 2-3 hours to obtain the modified silane coupling agent.

[0008] S2: Hydrolyzed modified silane coupling agent

[0009] In a hydrolysis container, deionized water and anhydrous ethanol are poured in sequentially, with a volume ratio of 1:0.8-1. The deionized water and anhydrous ethanol are stirred evenly at a speed of 50-100 r / min using a stirring rod. Then, the modified silane coupling agent is slowly poured in and stirred continuously for 5-10 min. At this point, the solution becomes clear. Stirring is stopped, and the solution is allowed to stand for 30-40 min to obtain the hydrolyzed modified silane coupling agent.

[0010] S3: Apply cold compress to the reaction vessel and add phosphorus-free metal surface treatment agent and citric acid.

[0011] Add an ice-water mixture to the reaction vessel to lower the temperature of the inner wall of the reaction vessel to 15-18℃. Store deionized water in a cold storage room and cool it down. Using a temperature sensor and controller installed on the inner wall of the reaction vessel, turn on the water pump in the cold storage room to transport the deionized water in the cold storage room to the reaction vessel through an insulated pipe. Turn on the stirrer to stir the deionized water. Then add the phosphorus-free metal surface treatment agent and citric acid and continue stirring.

[0012] S4: Pressurize, cool, and adjust pH.

[0013] Open the pressurized air inlet valve to pressurize the reaction vessel, then add ammonia water to the reaction vessel while stirring, adjust the pH value in the reaction vessel to dissolve citric acid, and then lower the temperature of the reaction vessel through an ice-water bath.

[0014] S5: Add EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mix, and restore to room temperature and pressure.

[0015] EDTA-4Na is added to the reaction vessel using a high-pressure injection pump and stirred until the solid is completely dissolved. Then, ammonia is added to the reaction vessel to adjust the pH value, followed by the addition of hydrolyzed modified silane coupling agent. The mixture is stirred until homogeneous, and the reaction vessel is brought back to room temperature and pressure. The mixture is then stirred with a stirrer until the solution in the reaction vessel becomes clear and transparent, thus obtaining a phosphorus-free and heavy metal-free ceramic agent.

[0016] Further, step S1 involves adding tetradecyltrimethylammonium bromide to the silane coupling agent to modify it, specifically including the following steps:

[0017] S1.1: Add the silane coupling agent to the stirred container, then add sufficient tetradecyltrimethylammonium bromide to the dropper. Install the dropper on the stirred container, start the stirred container, and stir the silane coupling agent at a low speed of 50-100 r / min. At the same time, add tetradecyltrimethylammonium bromide to the silane coupling agent at a rate of 1-3 mL / s through the dropper until the volume ratio of the added tetradecyltrimethylammonium bromide to the silane coupling agent is 1:1-1.5. Then turn off the dropper to obtain a mixed solution.

[0018] S1.2: Under a stirring environment of 50-100 r / min, add anhydrous ethanol with a volume ratio of 1:1-1.5 to the mixed solution. Then, heat the temperature of the stirring container to 70-80℃ in a water bath and maintain this temperature for 2-3 hours to obtain the modified silane coupling agent.

[0019] Further, step S3 involves cooling the reaction vessel and adding a phosphorus-free metal surface treatment agent and citric acid, specifically including the following steps:

[0020] S3.1: Add an ice-water mixture to the reaction vessel and keep the ice-water mixture warm for 5-10 minutes to reduce the temperature of the inner wall of the reaction vessel to 12-18°C, and then drain the ice-water mixture.

[0021] S3.2: Store deionized water in a cold storage room and cool it down to 12-18℃ through the cold storage room;

[0022] S3.3: When the temperature sensor installed on the inner wall of the reaction vessel detects that the temperature of the inner wall of the reaction vessel has dropped to 12-18℃, the controller will turn on the water pump in the cold storage compartment to transport the deionized water in the cold storage compartment to the reaction vessel through the heat preservation pipe.

[0023] S3.4: Turn on the stirrer and stir the deionized water at a speed of 50-100 r / min. Then, slowly add 20-25 parts of 2-2.5 g / L of phosphorus-free metal surface treatment agent while stirring, and then add 1-2 parts of citric acid. Continue stirring at a speed of 50-100 r / min.

[0024] Furthermore, after step S3.3 is completed, deionized water in the cold storage room is introduced into the reaction vessel. If the pressure sensor in the cold storage room detects that the pressure in the cold storage room is lower than the threshold, the water pump in the cold storage room will be shut off by the controller.

[0025] Because ammonia is volatile, appropriately lowering the temperature can make the ammonia less reactive and slow down its evaporation.

[0026] When the temperature sensor installed on the inner wall of the reaction vessel detects that the temperature of the inner wall of the reaction vessel has dropped to 12-18℃, the controller will turn on the water pump in the cold storage compartment to transport the deionized water in the cold storage compartment to the reaction vessel through the heat-insulated pipe. Once the temperature of the inner wall of the reaction vessel drops to the required temperature, the deionized water can be automatically transported into the reaction vessel without the need for manual temperature measurement and addition of deionized water. This automates and makes the preparation process more intelligent, saving labor costs.

[0027] Subsequently, deionized water from the cold storage compartment is pumped into the reaction vessel. If the pressure sensor in the cold storage compartment detects that the pressure inside the cold storage compartment is lower than the threshold, the water pump in the cold storage compartment will be shut off by the controller.

[0028] Further, step S4, pressurizing, cooling, and adjusting the pH value, specifically includes the following steps:

[0029] S4.1: Open the pressurization inlet valve to pressurize the reaction vessel and increase the pressure inside the reaction vessel to 130-135 kPa;

[0030] S4.2: Add ammonia water to the reaction vessel using a high-pressure injection pump, and maintain the stirring speed at 50-100 r / min using a stirrer to adjust the pH in the reaction vessel to 4.5-5, at which point the citric acid will dissolve;

[0031] S4.3: Then, the temperature of the reaction vessel is lowered to 12-18°C by an ice-water bath, and stirring is continued while maintaining this temperature.

[0032] Further, step S5 involves adding EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mixing them, and restoring the reaction to room temperature and pressure. This specifically includes the following steps:

[0033] S5.1: Add 2-4 parts of EDTA-4Na to the reaction vessel using a high-pressure injection pump, and stir for 2-4 minutes until the solid is completely dissolved;

[0034] S5.2: After adding EDTA-4Na, the pH value in the reaction vessel decreases. Then, ammonia water with a molar ratio of 1:0.5-1 to EDTA-4Na is added to the reaction vessel to adjust the pH value in the reaction vessel to 5-5.5.

[0035] S5.3: Add 1-2 parts of hydrolyzed modified silane coupling agent and stir with a stirrer for 1-3 minutes;

[0036] S5.4: Heat to room temperature in a water bath, then reduce the pressure in the reaction vessel to atmospheric pressure using a pressure reducing valve, and stir for 20-25 minutes until the solution becomes clear and transparent to obtain a phosphorus-free and heavy metal-free ceramic agent.

[0037] Furthermore, the silane coupling agent in step S1 is vinyltriethoxysilane, and the phosphorus-free metal surface treatment agent in step S3 is hexafluorozirconic acid or fluorozirconic acid.

[0038] Furthermore, in step S5, the ambient temperature range is 20-25℃, and the ambient pressure range is 100-101KPa.

[0039] An environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent is prepared by the above-mentioned preparation method of the environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent.

[0040] The beneficial effects are: 1. By replacing the metal surface treatment agent component in the ceramic coating agent with phosphoric acid or fluorozirconic acid that does not contain phosphorus, the present invention ensures the passivation effect of the ceramic coating agent without adding phosphorus and heavy metal elements, thus achieving the effect of protecting the environment, reducing pollution, and being environmentally friendly and green.

[0041] 2. In the preparation step of this invention, ammonia water is added to adjust the pH value of the reaction vessel to 4.5-5. Citric acid can act as a complexing agent in the process, so it is easy to flocculate in the solution and not easy to dissolve. The reaction vessel after adjusting the pH value can dissolve citric acid more quickly. Moreover, a neutral to slightly acidic environment is less likely to cause citric acid to flocculate than an acidic environment, so that the final precipitant is less likely to be affected by the flocculation of citric acid and thus its performance is not affected.

[0042] 3. In the preparation step, the present invention involves cooling and pressurization. Since ammonia is volatile, appropriately lowering the temperature can make the ammonia less active and slow down the volatilization effect. Furthermore, the saturated vapor pressure of ammonia is about 130 kPa, which is higher than the 100 kPa of atmospheric pressure. Therefore, it is easy to volatilize under atmospheric pressure. Pressurization is also carried out to further prevent volatilization and ensure that the adjusted pH value will not change again due to the volatilization of ammonia. This allows citric acid and EDTA-4Na to dissolve completely, ensuring the performance of the final ceramic agent.

[0043] 4. This invention modifies the silane coupling agent by using tetradecyltrimethylammonium bromide. Currently, when applying a ceramic agent to the metal surface to passivate the metal and achieve corrosion resistance, an anti-corrosion coating is usually applied next. Existing anti-corrosion coatings often contain clay as a filler. However, clay has poor hydrophilicity and is difficult to bond with the ceramic agent. The ceramic agent modified by tetradecyltrimethylammonium bromide can modify the clay in the anti-corrosion coating, resulting in better adhesion between the ceramic agent and the anti-corrosion coating applied to the metal surface. This facilitates the application of the anti-corrosion coating after applying the ceramic agent to the metal surface.

[0044] 5. This invention uses a temperature sensor and controller to automatically deliver deionized water into the reaction vessel once the temperature of the inner wall of the reaction vessel drops to the required temperature, eliminating the need for manual temperature measurement and addition of deionized water. This automates and enhances the intelligence of the preparation process, saving labor costs. Attached Figure Description

[0045] Figure 1 The flowchart illustrates the preparation method of the environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent used in the embodiments of the present invention.

[0046] Figure 2 The table below shows the composition and conditions of the environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent used in the embodiments of the present invention.

[0047] Figure 3 This is a table showing the experimental data from a comparative neutral salt spray test of the present invention.

[0048] Figure 4 The table shows the experimental results of the coating effect of acrylic metallic paint in the comparative example of the present invention. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1

[0051] An environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method, such as Figures 1-2 As shown, the specific steps include:

[0052] S1: Modify the silane coupling agent by adding tetradecyltrimethylammonium bromide.

[0053] Add the silane coupling agent, specifically vinyltriethoxysilane, to the stirred container. Then, add sufficient tetradecyltrimethylammonium bromide to the dropper. Install the dropper on the stirred container and start the stirred container. Stir the vinyltriethoxysilane at a low speed of 50 r / min. At the same time, add tetradecyltrimethylammonium bromide to the vinyltriethoxysilane at a rate of 1 mL / s through the dropper until the volume ratio of the added tetradecyltrimethylammonium bromide to vinyltriethoxysilane is 1:1. Then, turn off the dropper to obtain a mixed solution.

[0054] Under stirring conditions of 50 r / min, anhydrous ethanol with a volume ratio of 1:1 to the mixed solution was added. Then, the temperature inside the stirring container was heated to 80°C in a water bath and maintained at this temperature for 2 hours to ensure that tetradecyltrimethylammonium bromide and vinyltriethoxysilane were thoroughly mixed in the ethanol solvent, thus obtaining the modified silane coupling agent.

[0055] S2: Hydrolyzed modified silane coupling agent

[0056] In a hydrolysis container, deionized water and anhydrous ethanol are added sequentially, with a volume ratio of 1:1. The deionized water and anhydrous ethanol are stirred evenly at a speed of 50 r / min using a stirring rod. Then, the modified silane coupling agent is slowly poured in. At the beginning of the addition of the modified silane coupling agent, the solution will show stratification due to the presence of aqueous and organic phases. After stirring for 5 minutes to mix evenly, ethanol is used as the solvent, and the solution no longer separates into layers and becomes clear. Stirring is stopped, and the solution is allowed to stand for 30 minutes to obtain the hydrolyzed modified silane coupling agent.

[0057] S3: Apply cold compress to the reaction vessel and add phosphorus-free metal surface treatment agent and citric acid.

[0058] Add an ice-water mixture to the reaction vessel and keep the mixture warm for 5 minutes to reduce the temperature of the inner wall of the reaction vessel to 15°C. Then drain the ice-water mixture.

[0059] Deionized water is stored in a cold storage room and cooled to 15°C using the cold storage room.

[0060] Turn on the stirrer and stir the deionized water at a speed of 50 r / min. Then, slowly add 22 parts of 2 g / L hexafluorozirconic acid and 1 part of citric acid while stirring. Continue stirring at a speed of 50 r / min.

[0061] S4: Pressurize, cool, and adjust pH.

[0062] Open the pressurization valve to pressurize the reaction vessel and increase the pressure inside the reaction vessel to 130 kPa. Since the saturated vapor pressure of ammonia is about 130 kPa, which is greater than the atmospheric pressure of 100 kPa, it is easy to volatilize under atmospheric pressure. Pressurization is used to prevent volatilization.

[0063] Ammonia water is added to the reaction vessel using a high-pressure injection pump, and the stirring speed is maintained at 50 r / min using a stirrer to adjust the pH of the reaction vessel to 4.5, at which point the citric acid dissolves.

[0064] The reaction vessel temperature was then lowered to 15°C using an ice-water bath, and stirring was continued at this temperature to prevent ammonia from evaporating.

[0065] S5: Add EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mix, and restore to room temperature and pressure.

[0066] Add 2 parts of EDTA-4Na to the reaction vessel using a high-pressure injection pump and stir for 4 minutes until the solid is completely dissolved.

[0067] After adding EDTA-4Na, the pH value in the reaction vessel decreased. Then, ammonia water with a molar ratio of 1:1 to EDTA-4Na was added to the reaction vessel to adjust the pH value in the reaction vessel to 5.5. Then, 1 part of hydrolyzed modified silane coupling agent was added and stirred for 2 minutes with a stirrer.

[0068] The solution is heated to 20°C in a water bath, and then the pressure inside the reaction vessel is reduced to 101 kPa using a pressure reducing valve. The mixture is stirred for 20 minutes until the solution becomes clear and transparent, thus obtaining a phosphorus-free and heavy metal-free ceramic agent.

[0069] Example 2

[0070] An environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method, such as Figures 1-2 As shown, the specific steps include:

[0071] S1: Modify the silane coupling agent by adding tetradecyltrimethylammonium bromide.

[0072] Add the silane coupling agent, specifically vinyltriethoxysilane, to the stirred container. Then, add sufficient tetradecyltrimethylammonium bromide to the dropper. Install the dropper on the stirred container and start the stirred container. Stir the vinyltriethoxysilane at a low speed of 50 r / min. At the same time, add tetradecyltrimethylammonium bromide to the vinyltriethoxysilane at a rate of 1 mL / s through the dropper until the volume ratio of the added tetradecyltrimethylammonium bromide to vinyltriethoxysilane is 1:1.5. Then, turn off the dropper to obtain a mixed solution.

[0073] Under a stirring environment of 100 r / min, anhydrous ethanol with a volume ratio of 1:1 to the mixed solution is added. Then, the temperature inside the stirring container is heated to 80°C in a water bath and maintained at this temperature for 2 hours to ensure that tetradecyltrimethylammonium bromide and vinyltriethoxysilane are thoroughly mixed in the ethanol solvent, thus obtaining a modified silane coupling agent. When applying a ceramic coating to a metal surface to passivate the metal and achieve corrosion resistance, an anti-corrosion coating is usually applied next. Existing anti-corrosion coatings often contain clay as a filler; however, clay has poor hydrophilicity and is difficult to bond with the ceramic coating. The ceramic coating modified by tetradecyltrimethylammonium bromide can modify the clay in the anti-corrosion coating, resulting in better adhesion between the ceramic coating and the anti-corrosion coating on the metal surface, making it easier to apply the anti-corrosion coating after applying the ceramic coating to the metal surface.

[0074] S2: Hydrolyzed modified silane coupling agent

[0075] In a hydrolysis container, deionized water and anhydrous ethanol are poured in sequentially, with a volume ratio of 1:0.8. The deionized water and anhydrous ethanol are stirred evenly at a speed of 100 r / min using a stirring rod. Then, the modified silane coupling agent is slowly poured in. At the beginning of the addition of the modified silane coupling agent, the solution will show stratification due to the presence of aqueous and organic phases. After stirring for 5 minutes to mix evenly, ethanol is used as the solvent, and the solution no longer separates into layers and becomes clear. Stirring is stopped, and the solution is allowed to stand for 40 minutes to obtain the hydrolyzed modified silane coupling agent.

[0076] S3: Apply cold compress to the reaction vessel and add phosphorus-free metal surface treatment agent and citric acid.

[0077] Add an ice-water mixture to the reaction vessel and keep the mixture warm for 5 minutes to reduce the temperature of the inner wall of the reaction vessel to 15°C. Then drain the ice-water mixture.

[0078] Deionized water is stored in a refrigerator and cooled to 15°C. Because ammonia is volatile, lowering the temperature appropriately can make the ammonia less reactive and slow down its evaporation.

[0079] If the temperature sensor installed on the inner wall of the reaction vessel detects that the temperature of the inner wall of the reaction vessel has dropped to 15°C, the controller will turn on the water pump in the cold storage compartment to transport the deionized water in the cold storage compartment to the reaction vessel through the heat-insulated pipe. Once the temperature of the inner wall of the reaction vessel drops to the required temperature, the deionized water can be automatically transported to the reaction vessel without the need for manual temperature measurement and addition of deionized water. This automates and makes the preparation process more intelligent, saving labor costs.

[0080] Subsequently, deionized water from the cold storage compartment is introduced into the reaction vessel. If the pressure sensor in the cold storage compartment detects that the pressure inside the cold storage compartment is lower than the threshold, the water pump in the cold storage compartment will be shut off by the controller.

[0081] Turn on the stirrer and stir the deionized water at a speed of 50 r / min. Then, slowly add 25 parts of 2.5 g / L hexafluorozirconic acid and 2 parts of citric acid while stirring. Continue stirring at a speed of 50 r / min.

[0082] S4: Pressurize, cool, and adjust pH.

[0083] Open the pressurization valve to pressurize the reaction vessel and increase the pressure inside the reaction vessel to 130 kPa. Since the saturated vapor pressure of ammonia is about 130 kPa, which is greater than the atmospheric pressure of 100 kPa, it is easy to volatilize under atmospheric pressure. Pressurization is used to prevent volatilization.

[0084] Ammonia water is added to the reaction vessel using a high-pressure injection pump, and the stirring speed is maintained at 50 r / min using a stirrer to adjust the pH of the reaction vessel to 4.5, at which point the citric acid dissolves.

[0085] The reaction vessel temperature was then lowered to 15°C using an ice-water bath, and stirring was continued at this temperature to prevent ammonia from evaporating.

[0086] S5: Add EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mix, and restore to room temperature and pressure.

[0087] Add 4 parts of EDTA-4Na to the reaction vessel using a high-pressure injection pump and stir for 4 minutes until the solid is completely dissolved.

[0088] After adding EDTA-4Na, the pH value in the reaction vessel decreased. Then, ammonia water with a molar ratio of 1:1 to EDTA-4Na was added to the reaction vessel to adjust the pH value in the reaction vessel to 5.5. Then, 2 parts of hydrolyzed modified silane coupling agent were added and stirred for 2 minutes with a stirrer.

[0089] The solution is heated to 20°C in a water bath, and then the pressure inside the reaction vessel is reduced to 100 kPa using a pressure reducing valve. The mixture is stirred for 20 minutes until the solution becomes clear and transparent, thus obtaining a phosphorus-free and heavy metal-free ceramic agent.

[0090] Example 3

[0091] An environmentally friendly, phosphorus-free, and heavy metal-free ceramic coating agent and its preparation method, such as Figures 1-2 As shown, the specific steps include:

[0092] S1: Modify the silane coupling agent by adding tetradecyltrimethylammonium bromide.

[0093] Add the silane coupling agent, specifically vinyltriethoxysilane, to the stirred container. Then, add sufficient tetradecyltrimethylammonium bromide to the dropper. Install the dropper on the stirred container and start the stirred container. Stir the vinyltriethoxysilane at a low speed of 100 r / min. At the same time, add tetradecyltrimethylammonium bromide to the vinyltriethoxysilane at a rate of 3 mL / s through the dropper until the volume ratio of the added tetradecyltrimethylammonium bromide to vinyltriethoxysilane is 1:1.5. Then, turn off the dropper to obtain a mixed solution.

[0094] Under a stirring environment of 100 r / min, anhydrous ethanol with a volume ratio of 1:1.5 to the mixed solution is added. Then, the temperature inside the stirring container is heated to 70°C in a water bath and maintained at this temperature for 3 hours to ensure that tetradecyltrimethylammonium bromide and vinyltriethoxysilane are thoroughly mixed in the ethanol solvent, thus obtaining a modified silane coupling agent. When applying a ceramic coating to a metal surface to passivate the metal and achieve corrosion resistance, an anti-corrosion coating is usually applied next. Existing anti-corrosion coatings often contain clay as a filler; however, clay has poor hydrophilicity and is difficult to bond with the ceramic coating. The ceramic coating modified with tetradecyltrimethylammonium bromide can modify the clay in the anti-corrosion coating, resulting in better adhesion between the ceramic coating and the anti-corrosion coating on the metal surface, making it easier to apply the anti-corrosion coating after applying the ceramic coating to the metal surface.

[0095] S2: Hydrolyzed modified silane coupling agent

[0096] In a hydrolysis container, deionized water and anhydrous ethanol are added sequentially, with a volume ratio of 1:1. The deionized water and anhydrous ethanol are stirred evenly at a speed of 50 r / min using a stirring rod. Then, the modified silane coupling agent is slowly poured in. At the beginning of the addition of the modified silane coupling agent, the solution will show stratification due to the presence of aqueous and organic phases. After stirring for 5 minutes to mix evenly, ethanol is used as the solvent, and the solution no longer separates into layers and becomes clear. Stirring is stopped, and the solution is allowed to stand for 30 minutes to obtain the hydrolyzed modified silane coupling agent.

[0097] S3: Apply cold compress to the reaction vessel and add phosphorus-free metal surface treatment agent and citric acid.

[0098] Add an ice-water mixture to the reaction vessel and keep the mixture warm for 5 minutes to lower the temperature of the inner wall of the reaction vessel to 18°C. Then drain the ice-water mixture.

[0099] Deionized water is stored in a refrigerator and cooled to 18°C. Because ammonia is volatile, lowering the temperature appropriately can make the ammonia less reactive and slow down its evaporation.

[0100] If the temperature sensor installed on the inner wall of the reaction vessel detects that the temperature of the inner wall of the reaction vessel has dropped to 18°C, the controller will turn on the water pump in the cold storage compartment to transport the deionized water in the cold storage compartment to the reaction vessel through the heat-insulated pipe. Once the temperature of the inner wall of the reaction vessel drops to the required temperature, the deionized water can be automatically transported into the reaction vessel without the need for manual temperature measurement and addition of deionized water. This automates and makes the preparation process more intelligent, saving labor costs.

[0101] Subsequently, deionized water from the cold storage compartment is introduced into the reaction vessel. If the pressure sensor in the cold storage compartment detects that the pressure inside the cold storage compartment is lower than the threshold, the water pump in the cold storage compartment will be shut off by the controller.

[0102] Turn on the stirrer and stir the deionized water at a speed of 100 r / min. Then, slowly add 20 parts of 2.5 g / L hexafluorozirconic acid and 1 part of citric acid while stirring. Continue stirring at a speed of 100 r / min.

[0103] S4: Pressurize, cool, and adjust pH.

[0104] Open the pressurization valve to pressurize the reaction vessel and increase the pressure inside the reaction vessel to 135 kPa. Since the saturated vapor pressure of ammonia is about 135 kPa, which is greater than the atmospheric pressure of 100 kPa, it is easy to volatilize under atmospheric pressure. Pressurization is used to prevent volatilization.

[0105] Ammonia water is added to the reaction vessel using a high-pressure injection pump, and the stirring speed is maintained at 50 r / min using a stirrer to adjust the pH of the reaction vessel to 4.5, at which point the citric acid dissolves.

[0106] The temperature of the reaction vessel was then lowered to 18°C ​​using an ice-water bath, and stirring was continued at this temperature to prevent ammonia from evaporating.

[0107] S5: Add EDTA-4Na and the hydrolyzed modified silane coupling agent to the reaction vessel, mix, and restore to room temperature and pressure.

[0108] Add 2 parts of EDTA-4Na to the reaction vessel using a high-pressure injection pump and stir for 4 minutes until the solid is completely dissolved.

[0109] After adding EDTA-4Na, the pH value in the reaction vessel decreased. Then, ammonia water with a molar ratio of 1:1 to EDTA-4Na was added to the reaction vessel to adjust the pH value in the reaction vessel to 5.5. Then, 1 part of hydrolyzed modified silane coupling agent was added and stirred for 2 minutes with a stirrer.

[0110] The solution is heated to 25°C in a water bath, and then the pressure inside the reaction vessel is reduced to 101 kPa using a pressure reducing valve. The mixture is stirred for 20 minutes until the solution becomes clear and transparent, thus obtaining a phosphorus-free and heavy metal-free ceramic agent.

[0111] Comparative Example 1

[0112] Compared with Example 1, this comparative example uses a commercially available phosphating agent, specifically YJ-730 iron-based three-in-one cleaning agent sold by Wenzhou Yijing Cleaning Agent Co., Ltd.

[0113] The ceramic coating agent obtained in Example 1, the commercially available phosphating agent in Comparative Example 1, the ceramic coating agent obtained in Comparative Example 2, and the ceramic coating agent obtained in Comparative Example 3 were used to form a film on the surface of metal plates, and their corrosion resistance was tested. The specific process was as follows: the surface of the steel plate was polished, and pickled with a mixed acid solution of 10% HNO3, 2.5% H3PO4, and 1.5% H2SO4 by volume. The steel plate was immersed in the mixed acid solution for 2 minutes, and then washed twice with deionized water. The steel plate was then immersed in the ceramic coating agent prepared in Example 1, the commercially available phosphating agent in Comparative Example 1, the ceramic coating agent prepared in Comparative Example 2, and the ceramic coating agent prepared in Comparative Example 3, respectively, to obtain the film-forming steel plates, which were labeled as Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, and neutral salt spray tests were conducted on them respectively.

[0114] The test temperature was set at 25°C and the humidity at 96%. A salt solution containing 5% sodium chloride and a pH of 6.5 was sprayed using a spray device, allowing the salt spray to settle onto the steel plates used in Examples 1, 1, 2, and 3. The surface corrosion status was observed and recorded in a table, as follows: Figure 3 As shown, the corrosion resistance of the phosphating agent prepared by this invention is not much different from that of commercially available phosphating agents, and it also has the advantages of being free of phosphorus and heavy metals.

[0115] Comparative Example 2

[0116] Compared with Example 1, Comparative Example 2 differs in that the silane coupling agent is not modified, and the hydrolyzed modified silane coupling agent is replaced with an equal amount of silane coupling agent.

[0117] Comparative Example 3

[0118] Compared to Example 1, tetradecyltrimethylammonium bromide was replaced with an equal amount of tetradecyltrimethylammonium chloride, otherwise the same as in Example 1.

[0119] The ceramic coating agent obtained in Example 1, the commercially available phosphating agent in Comparative Example 1, the ceramic coating agent obtained in Comparative Example 2, and the ceramic coating agent obtained in Comparative Example 3 were used to form films on steel plates. Specifically, the steel plate surface was polished, and the plates were pickled with a mixed acid solution containing 10% HNO3, 2.5% H3PO4, and 1.5% H2SO4 by volume. The steel plates were immersed in the mixed acid solution for 2 minutes, then removed and washed twice with deionized water. The steel plates were then immersed in the ceramic coating agent prepared in Example 1. Steel plates with film-forming properties were obtained by mixing the commercially available phosphating agent of Comparative Example 1, the ceramic coating agent prepared in Comparative Example 2, and the ceramic coating agent prepared in Comparative Example 3. These plates were labeled as Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Commercially available acrylic metallic paint was applied to the surfaces of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. Specifically, the commercially available acrylic anti-rust paint was RAL-7035 acrylic metallic paint sold by Shanghai Caizhen Industrial Co., Ltd. The coating effect of the acrylic metallic paint was observed and recorded in a table, as follows: Figure 4 As shown, the modified silane coupling agent obtained by the present invention exhibits better adhesion to acrylic metallic paint.

[0120] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing an environmentally friendly, phosphorus-free, heavy metal-free vitrification agent, characterized by, Specifically comprising the following steps: S1: adding tetradecyl trimethyl ammonium bromide to the silane coupling agent to modify the silane coupling agent The silane coupling agent is added to the stirring container, and then tetradecyl trimethyl ammonium bromide is added to the dropping device. The dropping device is installed on the stirring container, the stirring container is started to stir the silane coupling agent at low speed, and then tetradecyl trimethyl ammonium bromide is added to the silane coupling agent through the dropping device. Then, the dropping device is closed to obtain a mixed solution. In the stirring environment, anhydrous ethanol is added to the mixed solution, and then the stirring container is heated by a water bath. Then, the temperature is kept constant for 2-3 hours to obtain a modified silane coupling agent. The silane coupling agent is vinyl triethoxysilane; S2: hydrolysis of the modified silane coupling agent In the hydrolysis container, deionized water and anhydrous ethanol are poured in sequence, wherein the volume ratio of deionized water to anhydrous ethanol is 1:0.8-1. The deionized water and anhydrous ethanol are stirred uniformly at a speed of 50-100 r / min, and then the modified silane coupling agent is slowly poured in. The stirring is continued for 5-10 min, at which time the solution becomes clear. The stirring is stopped, and the solution is left to stand for 30-40 min to obtain the hydrolyzed modified silane coupling agent; S3: cold reaction container and add non-phosphorus metal surface treatment agent and citric acid An ice water mixture is added to the reaction container to reduce the temperature of the inner wall of the reaction container to 12-18℃. The deionized water is stored in a refrigeration chamber, and the deionized water in the refrigeration chamber is transported to the reaction container through a heat preservation pipeline by opening the water pump of the refrigeration chamber and the temperature sensor and controller installed on the inner wall of the reaction container. The stirrer is turned on to stir the deionized water, and then the non-phosphorus metal surface treatment agent and citric acid are added. The stirring is continued, and the non-phosphorus metal surface treatment agent is hexafluorozirconic acid or fluorozirconic acid; S4: pressurization and temperature reduction and pH adjustment The pressurization inlet valve is opened to pressurize the reaction container. Ammonia is added to the reaction container while stirring to adjust the pH value in the reaction container. The citric acid is dissolved, and then the temperature of the reaction container is reduced by an ice water bath; S5: add EDTA-4Na and hydrolyzed modified silane coupling agent to the reaction container and mix and restore normal temperature and pressure EDTA-4Na is added to the reaction container by a high-pressure injection pump. The stirring is continued until the solid is completely dissolved. Ammonia is added to the reaction container to adjust the pH value. The hydrolyzed modified silane coupling agent is added. The stirring is uniform. The reaction container is restored to normal temperature and pressure. The solution in the reaction container becomes clear and transparent by stirring until the solution in the reaction container becomes clear and transparent. A non-phosphorus and non-heavy metal taming agent is obtained.

2. A method for preparing an environmentally friendly, non-phosphorus, and non-heavy metal sealer according to claim 1, characterized in that, The step S1 of adding tetradecyl trimethyl ammonium bromide to the silane coupling agent to modify the silane coupling agent specifically comprises the following steps: S1.1: Add silane coupling agent into the stirring container, then add enough tetradecyl trimethyl ammonium bromide into the dropping device, install the dropping device on the stirring container, start the stirring container, and stir the silane coupling agent at a low speed of 50-100 r / min, while adding tetradecyl trimethyl ammonium bromide into the silane coupling agent through the dropping device at a speed of 1-3 mL / s, until the volume ratio of the added tetradecyl trimethyl ammonium bromide to the silane coupling agent is 1:1-1.5, then close the dropping device to obtain a mixed solution; S1.2: In the stirring environment at a speed of 50-100 r / min, add anhydrous ethanol into the mixed solution at a volume ratio of 1:1-1.5, then heat the temperature in the stirring container to 70-80℃ through a water bath pot, and keep the temperature, and constant temperature stirring for 2-3 h to obtain a modified silane coupling agent.

3. A method for preparing an environmentally friendly phosphorus-free and heavy metal-free tanning agent according to claim 1, characterized in that, The step S3 cools the reaction container and adds a non-phosphorus metal surface treatment agent and citric acid, and specifically includes the following steps: S3.1: Add an ice-water mixture into the reaction container, and perform heat preservation treatment on the ice-water mixture for 5-10 min, reduce the temperature of the inner wall of the reaction container to 12-18℃, and then discharge the ice-water mixture; S3.2: Store deionized water in a refrigeration chamber, and cool the deionized water in the refrigeration chamber to 12-18℃ through the refrigeration chamber; S3.3: When the temperature sensor installed on the inner wall of the reaction container detects that the temperature of the inner wall of the reaction container is reduced to 12-18℃, the water pump of the refrigeration chamber is started through the controller, and the deionized water in the refrigeration chamber is transported into the reaction container through the heat preservation pipeline; S3.4: Turn on the stirrer to stir the deionized water at a speed of 50-100 r / min, then slowly add 20-25 parts of 2-2.5 g / L non-phosphorus metal surface treatment agent and 1-2 parts of citric acid under stirring, and keep the stirring speed at 50-100 r / min for continuous stirring.

4. The method according to claim 3, wherein the method is characterized by, After the step S3.3 is completed, the deionized water in the refrigeration chamber is transported into the reaction container, and when the pressure sensor in the refrigeration chamber detects that the pressure in the refrigeration chamber is lower than a threshold value, the water pump of the refrigeration chamber is turned off through the controller.

5. The method according to claim 1, wherein the method is characterized by, The step S4 pressurizes, cools and adjusts the pH value, and specifically includes the following steps: S4.1: Open the pressurization air inlet valve to pressurize the reaction container, and increase the pressure in the reaction container to 130-135 KPa; S4.2: Add ammonia water into the reaction container through a high-pressure injection pump, and keep the stirring speed at 50-100 r / min through the stirrer, and adjust the pH value in the reaction container to 4.5-5; S4.3: Then reduce the temperature of the reaction container to 12-18℃ through an ice-water bath, and keep the temperature for continuous stirring.

6. The method according to claim 1, wherein the method is characterized by, The step S5 adds EDTA-4Na and hydrolyzed modified silane coupling agent into the reaction container, mixes and restores normal temperature and pressure, and specifically includes the following steps: S5.1: Add 2-4 parts of EDTA-4Na into the reaction container through a high-pressure injection pump, and stir for 2-4 min until the solid is completely dissolved; S5.2: After adding EDTA-4Na, the pH value in the reaction vessel is reduced, and then ammonia water is added into the reaction vessel at a molar ratio of 1:0.5-1 with EDTA-4Na, so as to adjust the pH value in the reaction vessel to 5-5.5; S5.3: 1-2 parts of the hydrolyzed modified silane coupling agent are added again, and stirred by the stirrer for 1-3 min; S5.4: heated to room temperature by water bath, and then the air pressure in the reaction vessel is reduced to normal pressure by the pressure reducing valve, and stirred by the stirrer for 20-25 min until the solution becomes clear and transparent, to obtain the phosphorus-free and heavy metal-free tanning agent.

7. The method according to claim 6, wherein the method is characterized by, The room temperature range in step S5 is 20-25°C, and the normal pressure range is 100-101 KPa.

8. An eco-friendly, phosphorus-free, heavy metal-free vitrification agent, characterized by, It is prepared by the preparation method of the environment-friendly phosphorus-free and heavy metal-free tanning agent according to any one of claims 1-7.

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