Chromium-free surface passivation treatment liquid and application thereof

Abstract

The invention belongs to the technical field of metal surface treatment, and provides chromium-free surface passivation treatment liquid and application thereof. The chromium-free surface passivation treatment liquid comprises the following components in percentage by weight: 30-70% of a silane hydrolysis solution, 4-7% of non-volatile organic acid, 5-25% of water-based resin, 1-5% of a water-soluble antirust agent, 0.1-2% of fluoride, 0.1-3% of an auxiliary agent and the balance of water, preparing a silane hydrolysis solution, namely mixing an organic silane coupling agent and an inorganic alkali solution, and sequentially performing hydrolysis and vacuum distillation to remove alcohol, so as to obtain the silane hydrolysis solution; the organosilane coupling agent comprises a first group and a second group, the first group comprises one or more of an epoxy group, an amino group, a vinyl group and a methacryloyloxy group, and the second group comprises one or more of a methoxy group, an ethyoxyl group and an acetoxy group. The chromium-free surface passivation treatment liquid provided by the invention is low in VOC content, and is more environment-friendly and safer.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and in particular to a chromium-free surface passivation liquid and its application. Background Technology

[0002] Freshly galvanized sheets are electrochemically reactive and prone to oxidation and corrosion during transportation and storage, leading to unnecessary material loss. Traditionally, the galvanizing industry used hexavalent chromium passivation solutions to treat fresh galvanized sheets, giving them excellent corrosion resistance. However, due to serious health and environmental (HS&E) issues, hexavalent chromium passivation solutions have been banned and are gradually being replaced by environmentally friendly passivation products. Among these, chromium-free passivation products based on silane technology have been widely used in the galvanizing industry. However, an inherent problem with current silane chromium-free passivation products is that the main byproduct of the hydrolysis of silane coupling agents is alcohol solvents (methanol or ethanol), which are classified as volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). These alcohol solvents are not removed in the current product manufacturing process. In addition, volatile acetic acid is often used as a catalyst in the silane hydrolysis process, and acetic acid is also classified as a VOC. These substances all contribute to a high VOC / HAP content in the final silane passivation product. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a chromium-free surface passivation solution and its application. The chromium-free surface passivation solution provided by this invention for galvanizing production lines has extremely low VOC / HAP content, making it more environmentally friendly and safer; this passivation solution can form a dense film on the galvanized sheet surface and has excellent corrosion resistance and comprehensive performance.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a chromium-free surface passivation treatment liquid, comprising the following components by weight percentage: The composition consists of 30-70% silane hydrolysis solution, 4-7% non-volatile organic acid, 5-25% water-based resin, 1-5% water-soluble rust inhibitor, 0.1-2% fluoride, 0.1-3% additives, and the remainder is water. The preparation method of the silane hydrolysis solution includes the following steps: A solution of an organosilane coupling agent and an inorganic base is mixed and then subjected to hydrolysis and vacuum distillation in sequence to obtain the silane hydrolysis solution. The solid content of the silane hydrolysis solution is 10-30%; The organosilane coupling agent comprises a first group and a second group, wherein the first group comprises one or more of an epoxy group, an amino group, a vinyl group, and a methacryloyloxy group, and the second group comprises one or more of a methoxy group, an ethoxy group, and an acetoxy group.

[0005] Preferably, the organosilane coupling agent includes one or more of (γ-aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and vinyltriacetoxysilane.

[0006] Preferably, the inorganic base is an alkali metal hydroxide and / or an alkaline earth metal hydroxide, wherein the alkali metal hydroxide includes one or more of potassium hydroxide, sodium hydroxide and lithium hydroxide, and the alkaline earth metal hydroxide includes magnesium hydroxide; The pH value of the inorganic base solution is 9-12.

[0007] Preferably, the temperature of the vacuum distillation is 30~80℃ and the vacuum degree is 50~200 Torr.

[0008] Preferably, the non-volatile organic acid includes one or more of oxalic acid, citric acid, and tannic acid.

[0009] Preferably, the waterborne resin includes one or more of waterborne acrylic resin, waterborne epoxy resin, waterborne polyurethane resin, waterborne silicone resin, waterborne fluorinated resin, and waterborne hyperbranched polymer.

[0010] Preferably, the water-soluble rust inhibitor includes one or more of rare earth compounds, vanadium compounds, and phosphorus-containing compounds, wherein the rare earth compounds include one or more of cerium compounds, lanthanum compounds, and samarium compounds, and the phosphorus-containing compounds include one or more of dihydrogen phosphate and 1-hydroxy-ethane-1,1-diphosphonic acid.

[0011] Preferably, the fluoride comprises one or more of transition metal fluorides and fluorosilicic acid; Fluorides of the transition metals include fluorozirconic acid and / or fluorotitanic acid.

[0012] Preferably, the additives include wetting agents, leveling agents, defoamers, and wax emulsions; Based on the weight percentage of the silane hydrolysis solution, the chromium-free surface passivation treatment solution contains 0.01% wetting agent, 0.1% leveling agent, 0.005% defoamer, and 2% wax emulsion.

[0013] This invention also provides the application of the chromium-free surface passivation solution described above in the protection of zinc plates.

[0014] This invention provides a chromium-free surface passivation treatment solution.

[0015] The chromium-free surface passivation solution provided by this invention has an extremely low VOC content, improving its environmental friendliness and safety. Simultaneously, the hydrolyzed silane molecules undergo a cross-linking reaction with the water-based resin, forming a dense protective film that gives it excellent corrosion resistance and overall performance. Detailed Implementation

[0016] This invention provides a chromium-free surface passivation treatment liquid, comprising the following components by weight percentage: The composition consists of 30-70% silane hydrolysis solution, 4-7% non-volatile organic acid, 5-25% water-based resin, 1-5% water-soluble rust inhibitor, 0.1-2% fluoride, 0.1-3% additives, and the remainder is water. The preparation method of the silane hydrolysis solution includes the following steps: A solution of an organosilane coupling agent and an inorganic base is mixed and then subjected to hydrolysis and vacuum distillation in sequence to obtain the silane hydrolysis solution. The solid content of the silane hydrolysis solution is 10-30%; The organosilane coupling agent comprises a first group and a second group, wherein the first group comprises one or more of an epoxy group, an amino group, a vinyl group, and a methacryloyloxy group, and the second group comprises one or more of a methoxy group, an ethoxy group, and an acetoxy group.

[0017] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0018] By weight percentage, the chromium-free surface passivation solution provided by this invention comprises 30-70% silane hydrolysis solution, preferably 30%, 35%, 40%, 45%, 50%, 54%, 55%, 60%, 65%, or 70%. In this invention, the solid content of the silane hydrolysis solution is 10-30%, preferably 10%, 15%, 20%, 24%, 25%, or 30%.

[0019] In this invention, the method for preparing the silane hydrolysis solution includes the following steps: A solution of an organosilane coupling agent and an inorganic base is mixed and then subjected to hydrolysis and vacuum distillation in sequence to obtain the silane hydrolysis solution.

[0020] In this invention, the organosilane coupling agent comprises a first group and a second group. The first group includes one or more of an epoxy group, an amino group, a vinyl group, and a methacryloxy group. The second group includes one or more of a methoxy group, an ethoxy group, and an acetoxy group. Preferably, the organosilane coupling agent has the structural formula R'(CH2) in this invention. nSiR3, where R' represents a first group and R represents a second group, and n = 0, 1, 2, or 3. In this invention, the organosilane coupling agent preferably comprises one or more of (γ-aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and vinyltriacetoxysilane, with (γ-aminopropyl)trimethoxysilane being more preferred.

[0021] In this invention, the inorganic base is preferably an alkali metal hydroxide and / or an alkaline earth metal hydroxide, wherein the alkali metal hydroxide preferably includes one or more of potassium hydroxide, sodium hydroxide, and lithium hydroxide, and more preferably sodium hydroxide; the alkaline earth metal hydroxide preferably includes magnesium hydroxide. In this invention, the inorganic base can stabilize the stability of the silane hydrolysis solution obtained by vacuum distillation.

[0022] In this invention, the pH value of the inorganic base solution is preferably 9 to 12, and more preferably 9, 10, 11 or 12.

[0023] In this invention, the preferred mass ratio of the organosilane coupling agent to the inorganic base solution is 180:430.

[0024] In this invention, the hydrolysis temperature is preferably 20~40℃, more preferably 30℃, and the hydrolysis time is preferably 0.5~2h. In this invention, the hydrolysis is preferably carried out in a reactor.

[0025] After hydrolysis, the present invention preferably performs vacuum distillation directly without any further treatment. In this invention, the vacuum distillation temperature is preferably 30-80℃, specifically 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, or 80℃; the vacuum degree is preferably 50-200 Torr, specifically 50 Torr, 60 Torr, 70 Torr, 80 Torr, 90 Torr, 100 Torr, 110 Torr, 120 Torr, 130 Torr, 140 Torr, 150 Torr, 160 Torr, 170 Torr, 180 Torr, 190 Torr, or 200 Torr. In this invention, the vacuum distillation time is preferably 8-12 hours, more preferably 10 hours; the vacuum distillation is preferably carried out under stirring conditions. In this invention, vacuum distillation can remove small molecule alcohols produced by the hydrolysis of organosilane coupling agents, ultimately reducing the alcohol content of the chromium-free surface passivation treatment solution, making it more environmentally friendly.

[0026] In this invention, the methanol (R3OH) content in the silane hydrolysis solution is preferably ≤200ppm.

[0027] In this invention, the reaction formula for the hydrolysis of the organosilane coupling agent is as follows: R'(CH2)n SiR3 + 3H2O → 3R3OH + R'(CH2) n Si(OH)3.

[0028] The chromium-free surface passivation solution provided by this invention comprises 4-7% non-volatile organic acid by weight percentage, specifically preferably 4%, 4.5%, 5%, 5.5%, 6%, 6.4%, 6.5%, or 7%. In this invention, the non-volatile organic acid preferably includes one or more of oxalic acid, citric acid, and tannic acid, more preferably oxalic acid. Compared to acetic acid, the non-volatile organic acid in this invention is non-volatile, making the chromium surface passivation solution more environmentally friendly and safer.

[0029] The chromium-free surface passivation solution provided by this invention comprises 5-25% aqueous resin by weight percentage, specifically preferably 5%, 7%, 10%, 12%, 15%, 18%, 20%, 22%, or 25%. In this invention, the aqueous resin preferably comprises one or more of aqueous acrylic resin, aqueous epoxy resin, aqueous polyurethane resin, aqueous silicone resin, aqueous fluorinated resin, and aqueous hyperbranched polymer, more preferably a mixture of aqueous acrylic resin and aqueous polyurethane resin; the mass ratio of the aqueous acrylic resin to the aqueous polyurethane resin in the mixture is preferably 7:5. In one specific embodiment of this invention, the aqueous acrylic resin is preferably UC8600 acrylic resin purchased from Opaldi. In this invention, the aqueous polyurethane resin is preferably PU8059 polyurethane resin purchased from Bolino. In this invention, the silane molecules in the silane hydrolysis solution and the aqueous resin crosslink to form a dense, highly water-resistant hybrid film on the zinc plating layer. This film provides the zinc layer with excellent corrosion resistance and other comprehensive properties.

[0030] The chromium-free surface passivation solution provided by this invention comprises 1-5% water-soluble rust inhibitor by weight percentage, specifically preferably 1%, 1.35%, 1.5%, 1.65%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. In this invention, the water-soluble rust inhibitor preferably comprises one or more of rare earth compounds, vanadium compounds, and phosphorus-containing compounds. In this invention, the rare earth compounds preferably comprise one or more of cerium compounds, lanthanum compounds, and samarium compounds. In this invention, the vanadium compounds preferably comprise one or more of vanadium(2,4-glutaric acid)oxide (IV), sodium metavanadate, and potassium metavanadate. In this invention, the cerium compounds preferably comprise one or more of cerium tartrate, cerium nitrate, and cerium tetrasulfate. In this invention, the lanthanum compounds preferably comprise one or more of lanthanum 4-hydroxycinnamate, lanthanum nitrate, and lanthanum chloride. In this invention, the samarium compounds preferably comprise one or more of samarium(III) nitrate, samarium(III) chloride, and samarium sulfate. In this invention, the phosphorus-containing compound preferably includes one or more of dihydrogen phosphate and 1-hydroxy-ethane-1,1-diphosphonic acid, more preferably dihydrogen phosphate. In this invention, the dihydrogen phosphate preferably includes one or more of sodium dihydrogen phosphate, potassium dihydrogen phosphate, and ammonium dihydrogen phosphate, more preferably ammonium dihydrogen phosphate. In a specific embodiment of this invention, the water-soluble rust inhibitor preferably includes vanadium bis(2,4-glutaric acid) oxide (IV) and ammonium dihydrogen phosphate, wherein the mass ratio of vanadium bis(2,4-glutaric acid) oxide (IV) to ammonium dihydrogen phosphate is preferably 0.35~0.45:1~1.2, specifically preferably 0.35:1 or 0.45:1.2.

[0031] The chromium-free surface passivation solution provided by this invention comprises 0.1-2% fluoride by weight, preferably 0.1%, 0.5%, 1%, 1.1%, 1.5%, or 2%. In this invention, the fluoride preferably comprises one or more of transition metal fluorides and fluorosilicic acid. In this invention, the transition metal fluoride preferably comprises fluorozirconic acid and / or fluorotitanic acid, more preferably fluorotitanic acid.

[0032] The chromium-free surface passivation solution provided by this invention comprises 0.1-3% by weight of additives, preferably including wetting agents, leveling agents, defoamers, and wax emulsions. Specifically, the wetting agent is preferably one or more of anionic, cationic, and nonionic wetting agents; the leveling agent is preferably one or more of anionic, cationic, and nonionic leveling agents; the defoamer is preferably one or more of anionic, cationic, and nonionic defoamers; and the wax emulsion is preferably one or more of anionic, cationic, and nonionic wax emulsions. Based on the weight percentage of the silane hydrolysis solution, the chromium-free surface passivation solution contains 0.01% wetting agent, 0.1% leveling agent, 0.005% defoamer, and 2% wax emulsion. In one specific embodiment of the present invention, the wetting agent is preferably JC002 purchased from Jihechang Company; the leveling agent is preferably JC7518 purchased from Jihechang Company; the defoamer is preferably CN4913 purchased from Qingnan Company; and the wax emulsion is preferably DHX50501E purchased from Dinghengxin Company.

[0033] By weight percentage, the chromium-free surface passivation solution provided by this invention comprises the balance being water. In this invention, the water is preferably deionized water.

[0034] In this invention, the pH value of the chromium-free surface passivation treatment solution is preferably 4.5 to 6.0.

[0035] In this invention, the preparation method of the chromium-free surface passivation solution preferably includes the following steps: A silane hydrolysis solution is mixed with water, and the pH of the system is adjusted to 4-5 using a non-volatile organic acid. Then, a fluoride, a water-soluble rust inhibitor, a water-based resin, and additives are added sequentially to obtain the chromium-free surface passivation treatment solution. In this invention, after adding the fluoride, water-soluble rust inhibitor, water-based resin, and additives, stirring is preferably also included. This invention does not specifically limit the stirring speed and time, as long as the system is mixed uniformly.

[0036] This invention also provides the application of the chromium-free surface passivation solution described above in the protection of galvanized sheets.

[0037] In this invention, the galvanized sheet is preferably a galvanized alloy sheet, and the galvanized alloy sheet is preferably a galvanized sheet, a galvanized aluminum-magnesium sheet, or an aluminum-zinc sheet.

[0038] In this invention, when the chromium-free surface passivation solution is applied to the protection of galvanized sheets, it preferably includes the following steps: The galvanized sheet is cleaned to obtain a clean galvanized sheet; The chromium-free surface passivation solution is applied to the clean galvanized sheet and then dried to protect the galvanized sheet.

[0039] In this invention, the cleaning process preferably includes sequentially performing an alkaline degreasing agent cleaning and a tap water rinse. The alkaline degreasing agent cleaning time is preferably 15 seconds. The tap water rinsing time is preferably 15 seconds. The drying process is preferably performed using hot air.

[0040] In this invention, the preferred application methods are scraping, rolling, dipping, or spraying. This invention does not specifically limit the amount of the applied chromium-free surface passivation solution; it can be set according to actual needs.

[0041] In this invention, the preferred drying temperature is 90°C. The drying time is not specifically limited, as long as it is sufficient to dry the chromium-free surface passivation solution.

[0042] In this invention, the thickness of the dry film formed by the chromium-free surface passivation treatment solution is preferably 0.5~1.2µm, specifically preferably 0.5µm, 0.6µm, 0.7µm, 0.8µm, 0.9µm, 1.0µm, 1.1µm or 1.2µm.

[0043] The following detailed description of the chromium-free surface passivation solution and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0044] Example 430g of deionized water (adjusted to pH ~9 with sodium hydroxide) was placed in a 20L reactor and slowly reacted with 180g of (3-aminopropyl)trimethoxysilane at about 30°C for 2h. Then, the mixture was slowly stirred at about 40°C and 50 Torr pressure for 10h to remove methanol, yielding a silane hydrolysis solution with a solid content of 24%.

[0045] The alcohol content in the silane hydrolysis solution before and after vacuum distillation was determined using gas chromatography-mass spectrometry (GC-MS), and the relative concentration of alcohol was determined by comparison with the conventional standard addition method of known standards using GC-MS. Before vacuum distillation, the methanol content in the silane hydrolysis solution was approximately 24%; after 10 hours of vacuum distillation, the residual methanol in the obtained silane hydrolysis solution was less than 200 ppm, and the silane hydrolysis solution was clear and transparent.

[0046] Other raw materials are sourced from: acrylic resin: UC8600 (product of Oubodi Company); polyurethane resin: PU8059 (product of Bolino Company); wetting agent: JC002 (product of Jihechang Company); leveling agent: JC7518 (product of Jihechang Company); defoamer: CN4913 (product of Qingnan Company); wax emulsion: DHX50501E (product of Dinghengxin Company).

[0047] Table 1 lists the formulations of chromium-free surface passivation solutions based on silane hydrolysis solutions.

[0048] Table 1. Formulation of Chromium-Free Surface Passivation Solution (by weight percentage)

[0049] Example 7 The difference from Example 6 is that the organosilane coupling agent (3-aminopropyl)trimethoxysilane used to prepare the silane hydrolysis solution is replaced with (3-aminopropyl)triethoxysilane, and the other operations are the same as in Example 6.

[0050] Comparative Example 1 XAF-200, a commercial chromium-free surface passivation solution (product of Shanghai Xingsai'er Surface Materials Co., Ltd.), uses a traditional silane hydrolysis solution and does not remove alcohol; the acid used is acetic acid. Therefore, the product has a relatively high VOC content.

[0051] Comparative Example 2 In Example 6, the silane hydrolysis solution was replaced with an aminosilane polymer hydrolysis solution, model FD-7252, purchased from Anhui Boiling Point New Materials Co., Ltd. (characteristics: low VOC content, environmentally friendly and safe).

[0052] The passivation solution prepared above was subjected to solution stability testing. The test conditions were incubation at 40℃ for 2 weeks (14 days), followed by observation of the solution state. In addition, the VOC value of the prepared passivation solution was calculated. Table 2 lists the solution stability test results and the corresponding calculated VOC values.

[0053] Table 2. Stability test results and calculated VOC values ​​of chromium-free surface passivation solution.

[0054] As can be seen from Table 2, the treatment solution obtained in Comparative Example 2 was unstable, so no further performance tests were conducted.

[0055] The chromium-free surface passivation solutions obtained in Examples 1-7 and Comparative Example 1, as well as the products of the comparative examples, were applied as follows: A galvanized (GI) sample (10cm × 15cm) was sprayed with an alkaline degreasing agent at 55℃ for 15 seconds, rinsed with tap water for 15 seconds, and dried with hot air. On the cleaned surface, the prepared chromium-free surface passivation solution (Table 1) was spread downwards using a #3 squeegee. Using an automatic discharge drying oven, with the plate temperature (PMT) set to 90℃, the resulting dry film thickness was approximately 1μm.

[0056] The performance of the chromium-free surface passivation solutions obtained in Examples 1-7 and the comparative products was tested as follows: 1) Corrosion resistance: 72hr neutral salt spray test (GB / T 10125-2012), and the area of ​​white rust on the board surface was observed after the test; 2) Damp heat resistance (GB / T 1740-2007): Damp heat test conditions were 50℃ / 95%Rh / 120hr, and the color difference change value (ΔE) of the board surface was measured after the test; 3) Yellowing resistance: The test conditions were baking at 200℃ for 20min, and the color difference change value (ΔE) of the board surface was measured after baking; 4) Coating properties (GB / T 9286-1998): Electrostatic powder coating is used, with curing conditions of 200℃ for 20 minutes. After curing, the adhesion of the coating film to the passivation plate is tested using the cross-cut adhesion test; grade 0 indicates that the coating film does not peel off. 5) Fingerprint resistance: Vaseline is applied to the passivation plate surface, and after 20 minutes, the Vaseline is wiped off. The color difference value change (ΔE) of the plate surface is measured. 6) Solvent resistance: The solvent is MEK. A 10mm cotton swab is used to wipe the plate back and forth 10 times at a 45° angle and a pressure of 500g. The plate surface ΔE is then measured.

[0057] The results are shown in Table 3.

[0058] Table 3 Performance Test Results

[0059] Table 3 shows that Examples 5, 6 and 7 provide performance comparable to currently commercially available silane passivation products (Comparative Example 1), but are more environmentally friendly and safer.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A chromium-free surface passivation treatment liquid, characterized in that, Includes the following components by weight percentage: The composition consists of 30-70% silane hydrolysis solution, 4-7% non-volatile organic acid, 5-25% water-based resin, 1-5% water-soluble rust inhibitor, 0.1-2% fluoride, 0.1-3% additives, and the remainder is water. The preparation method of the silane hydrolysis solution includes the following steps: A solution of an organosilane coupling agent and an inorganic base is mixed, and then subjected to hydrolysis and vacuum distillation to remove the alcohol, thereby obtaining the silane hydrolysis solution. The solid content of the silane hydrolysis solution is 10-30%; The organosilane coupling agent comprises a first group and a second group, wherein the first group comprises one or more of an epoxy group, an amino group, a vinyl group, and a methacryloyloxy group, and the second group comprises one or more of a methoxy group, an ethoxy group, and an acetoxy group.

2. The chromium-free surface passivation solution according to claim 1, characterized in that, The organosilane coupling agent includes one or more of (γ-aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and vinyltriacetoxysilane.

3. The chromium-free surface passivation solution according to claim 1, characterized in that, The inorganic base is an alkali metal hydroxide and / or an alkaline earth metal hydroxide, wherein the alkali metal hydroxide includes one or more of potassium hydroxide, sodium hydroxide, and lithium hydroxide; and the alkaline earth metal hydroxide includes magnesium hydroxide. The pH value of the inorganic base solution is 9-12.

4. The chromium-free surface passivation solution according to claim 1, characterized in that, The vacuum distillation temperature is 30~80℃, and the vacuum degree is 50~200 Torr.

5. The chromium-free surface passivation solution according to claim 1, characterized in that, The non-volatile organic acids include one or more of oxalic acid, citric acid, and tannic acid.

6. The chromium-free surface passivation solution according to claim 1, characterized in that, The waterborne resin includes one or more of the following: waterborne acrylic resin, waterborne epoxy resin, waterborne polyurethane resin, waterborne silicone resin, waterborne fluorinated resin, and waterborne hyperbranched polymer.

7. The chromium-free surface passivation solution according to claim 1, characterized in that, The water-soluble rust inhibitor includes one or more of rare earth compounds, vanadium compounds, and phosphorus-containing compounds. The rare earth compounds include one or more of cerium compounds, lanthanum compounds, and samarium compounds. The phosphorus-containing compounds include one or more of dihydrogen phosphate and 1-hydroxy-ethane-1,1-diphosphonic acid.

8. The chromium-free surface passivation solution according to claim 1, characterized in that, The fluorides include one or more of transition metal fluorides and fluorosilicic acids; Fluorides of the transition metals include fluorozirconic acid and / or fluorotitanic acid.

9. The chromium-free surface passivation solution according to claim 1, characterized in that, The additives include wetting agents, leveling agents, defoamers, and wax emulsions; Based on the weight percentage of the silane hydrolysis solution, the chromium-free surface passivation treatment solution contains 0.01% wetting agent, 0.1% leveling agent, 0.005% defoamer, and 2% wax emulsion.

10. The application of the chromium-free surface passivation solution according to any one of claims 1 to 9 in the protection of zinc plates.

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