A method for preparing a hydrophobic, corrosion-resistant waterborne feve fluorocarbon coating with high adhesion

Abstract

The application is a preparation method of a hydrophobic, corrosion-resistant water-based FEVE fluorocarbon coating with high adhesion. The method comprises the following steps: in the first step, perfluorooctyltriethoxysilane (FAS13), vinyl ether and glycidyl methacrylate (GMA) are added to deionized water for mixing, and a dispersion is obtained by ultrasonic dispersion; in the second step, the dispersion of the first step is added to a high-pressure reaction kettle, and NaHCO3 and an initiator are then added; CTFE monomers are then added, and the system is reacted at 40-70 DEG C for 6-9h under mechanical stirring to obtain a composite latex particle dispersion; the dispersion obtained in the second step is coated on a substrate, and dried at room temperature to obtain a water-based FEVE fluorocarbon coating. The application not only has better emulsification effect, but also endows the system with more superior performance, such as hydrophobicity and thermal stability, and provides a new idea for the multifunctional development of water-based FEVE resin.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water-based coating preparation, and particularly relates to a preparation method of water-based FEVE fluorocarbon paint with high adhesion, hydrophobicity and corrosion resistance. BACKGROUND

[0002] Water-based FEVE fluorocarbon emulsion is widely used in the ship and bridge industries due to its good weather resistance, chemical resistance, water resistance and environmental affinity. However, due to the inherent structural defects of water-based FEVE fluorocarbon paint, there is still a large gap in adhesion, hydrophobicity, organic corrosion resistance and corrosion resistance compared with solvent-based FEVE fluorocarbon paint. Therefore, how to further improve the related performance of water-based FEVE fluorocarbon paint is an important problem to be solved. Physical modification is the most commonly used method in the field of water-based FEVE coating modification at present.

[0003] At present, physical modification is still the most common and economical choice in coating modification systems. However, although this modification method can improve the performance of the coating, it has problems such as poor stability and poor compatibility. For a long time, small molecule emulsifiers such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) or their derivatives have been used in the emulsion polymerization of FEVE in industry. Related research results show that these fluorine-containing surfactants have high biological metabolic stability and potential biological toxicity, which is due to the presence of a perfluoro straight-chain hydrocarbon longer than C8 in their structure, so their environmental friendliness is weak. At the same time, the small molecule emulsifier cannot be removed in time after the reaction, which will reduce the water resistance and adhesion of the paint. In recent years, the research on amphiphilic oligomers as emulsifiers has gradually risen, and some silanes with special structures have amphiphilic properties in the hydrolysis and condensation process, so they are used as stabilizers at the oil-water interface. This oligomer emulsifier overcomes the shortcomings of traditional small molecule emulsifiers, reduces environmental pollution without reducing the original performance, and improves the performance of the coating in some aspects. Li et al. prepared a water-based organic-inorganic hybrid fluorocarbon coating with excellent transparency, ultraviolet resistance and thermal stability using polysiloxane precursor (MTES) as a stabilizer, but the hydrophobicity (water contact angle of only 95°) and corrosion resistance of the prepared coating were not satisfactory (Appl. Surf. Sci. 602 (2022) 154334). Therefore, it is still a great challenge to simply and efficiently prepare multifunctional water-based FEVE fluorocarbon paint using green chemical modification methods. SUMMARY

[0004] The application aims at the current technical limitations, and provides a preparation method of water-based FEVE fluorocarbon coating with hydrophobic, corrosion-resistant and high adhesion performance.

[0005] The technical scheme of the application is as follows:

[0006] A preparation method of a water-based FEVE fluorocarbon coating with hydrophobic, corrosion-resistant and high adhesion performance, comprising the following steps:

[0007] In the first step, perfluorooctyltriethoxysilane (FAS13), compound A and GMA are added to deionized water for mixing, and ultrasonic dispersion is performed for 10-40 min to obtain dispersion liquid B;

[0008] In the first step, perfluorooctyltriethoxysilane (FAS13), compound A and GMA are added to deionized water for mixing, and ultrasonic dispersion is performed for 10-40 min to obtain dispersion liquid B;

[0009] The compound A is one or more of the vinyl ethers;

[0010] The vinyl ether is specifically isobutyl vinyl ether (IBVE), hydroxybutyl vinyl ether (HBVE), propyl vinyl ether (NPVE) or diethylene glycol monovinyl ether (DIVE);

[0011] In the second step, the dispersion liquid B of the first step is added to a high-pressure reaction kettle, and then NaHCO3 and an initiator are added; then CTFE monomer is added under an oxygen-free state, and the system is reacted at 40-70 DEG C for 6-9 h under mechanical stirring to obtain P(CTFE-co-IBVE-co-GMA)@PFSQ composite latex particle dispersion liquid C;

[0012] In the second step, the dispersion liquid B of the first step is added to a high-pressure reaction kettle, and then NaHCO3 and an initiator are added; then CTFE monomer is added under an oxygen-free state, and the system is reacted at 40-70 DEG C for 6-9 h under mechanical stirring to obtain P(CTFE-co-IBVE-co-GMA)@PFSQ composite latex particle dispersion liquid C;

[0013] The initiator is one or more of water-soluble initiators potassium persulfate (KPS), ammonium persulfate (APS), azobisdimethylaminoformamidine hydrochloride (AIBA), and azobisdimethylimidazoline hydrochloride (AIBI).

[0014] In the third step, the dispersion liquid C obtained in the second step is coated on a substrate, and dried at room temperature for 12-36 hours to obtain a water-based FEVE fluorocarbon coating layer; the coating layer has a thickness of 40-60 microns.

[0015] The substrate is specifically a glass sheet, tinplate, leather, fabric, or steel plate.

[0016] In each 5*5 cm 2 of the substrate, 15-20 grams of the dispersion liquid is coated.

[0017] The present application has the following beneficial effects:

[0018] In the present application, FAS13 precursor is used as an emulsifier for the first time, which not only improves the emulsification effect, but also greatly improves the hydrophobicity of the coating layer (water contact angle is increased from 69° to 131°) compared with the previous work of the research group; the chemical adsorption layer of GMA and the substrate improves the adhesion of the coating layer (lap shear strength with the substrate is increased from 0.47 MPa to 0.92 MPa). The synergistic effect of the two improves the integrity of the coating layer, and greatly improves the corrosion resistance of the coating layer (the simulation impedance is increased by 3 times). The present application shows great potential in the development of multifunctional water-based FEVE coating layer. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The FT-IR spectrum obtained in Examples 3, 5-7 is shown in the figure;

[0020] Figure 2 The particle size distribution histogram of FEVEG2F y obtained in Examples 3, 5-7 is shown in the figure;

[0021] Figure 3 The lap shear strength diagram of FEVEG x coating obtained in Examples 1-4 is shown in the figure;

[0022] Figure 4 The lap shear strength diagram of FEVEG2F y coating obtained in Examples 3, 5-7 is shown in the figure;

[0023] Figure 5 The water contact angle diagram of FEVEG2F y coating obtained in Examples 3, 5-7 is shown in the figure;

[0024] Figure 6 The water contact angle diagram of FEVEG2F yNyquist plot of the coating. Detailed Implementation

[0025] Example 1:

[0026] The specific steps for preparing an aqueous fluorocarbon coating are as follows:

[0027] First, sodium dodecyl sulfate (SDS) (0.289 g, 1 mmol) and IBVE (4.000 g, 40 mmol) were added to 60 ml of deionized water and mixed. The mixture was then ultrasonically dispersed for 30 min to obtain dispersion A.

[0028] In the second step, 64g of dispersion A from the first step was added to a high-pressure reactor, followed by the addition of NaHCO3 (0.400g, 5mmol) and KPS (0.060g, 0.2mmol). The high-pressure reactor was then sealed and deoxygenated with nitrogen gas at 0.3MPa for 30 minutes. The reactor was then degassed and the pressure reduced to 10... -2 A vacuum was achieved by removing oxygen from the atmosphere below a certain pressure (mbar). Then, CTFE monomer (15,000 g) was added using a double weighing method (i.e., weighing the weight difference before and after the addition of CTFE gas). All polymerization processes were carried out in a 250 mL high-pressure reactor equipped with a rupture disc (3000 psi), pressure gauge, inlet and outlet valves, and a mechanical stirrer. The reactor was pressurized with nitrogen at 20 bar to check its seal. The entire reaction was carried out at 60°C with continuous stirring (200 rpm) for 8 hours. After the reaction was complete, the reactor was cooled and degassed to obtain an aqueous fluorocarbon emulsion (FEVE).

[0029] The third step involves further ultrasonically dispersing the obtained emulsion for 40 minutes, thoroughly cleaning the glass substrate with alcohol and alkaline detergent respectively, rinsing with deionized water, and drying. The ultrasonically treated latex particles are then coated onto the dried glass slide using a drop-coating method and dried at 60°C for 24 hours to obtain a coating with a thickness of 50±2μm.

[0030] The adhesion properties of the FEVE coating are as follows Figure 4 As shown, its lap shear strength and maximum tensile force are 0.493 MPa and 151.6 N, respectively.

[0031] Example 2:

[0032] The specific steps for preparing an aqueous fluorocarbon coating are as follows:

[0033] First step, sodium dodecyl sulfate (0.289 g, 1 mmol), IBVE (4.000 g, 40 mmol), GMA (0.736 g, 10 mmol) were added to 60 ml of deionized water and mixed while being dispersed using ultrasound for 30 min to obtain dispersion A;

[0034] Second step, 64 g of dispersion A from the first step was added to a high-pressure reactor, and NaHCO3(0.400 g, 5 mmol), KPS (0.060 g, 0.2 mmol) were added separately. After the high-pressure reactor was sealed, it was deoxygenated with 0.3 MPa of nitrogen for 30 min, then the high-pressure reactor was degassed and reduced to 10 -2 mbar to exclude oxygen to achieve a vacuum state. CTFE monomer (15.000 g) was added by the double weighing method (i.e. the difference in weight before and after the addition of CTFE gas was weighed). All polymerization processes were carried out in a 250 mL high-pressure reactor equipped with a bursting disc (3000 psi), a pressure gauge, inlet and outlet valves, and a mechanical stirring paddle. The high-pressure reactor was pressurized with 20 bar of nitrogen to check the sealing of the high-pressure reactor. The entire reaction was carried out at 60°C under continuous stirring (stirring rate of 200 rpm) for 8 h. After the reaction was completed, the high-pressure reactor was cooled and degassed to obtain an aqueous fluorocarbon emulsion (FEVEG1).

[0035] Third step, the obtained emulsion was further ultrasonically dispersed for 40 min, the glass sheet substrate was thoroughly cleaned with alcohol and alkaline detergent, rinsed with deionized water and dried. The ultrasonically treated latex particles were coated on the dried glass sheet by drop coating method, and dried at 60°C for 24 h to obtain a coating layer with a thickness of 50 ± 2 pm.

[0036] The adhesion properties of the FEVEG1 coating layer are shown in Table 1, and the lap shear strength and tensile maximum force are 0.693 MPa and 217.2 N, respectively. Figure 3

[0037] Example 3:

[0038] An aqueous fluorocarbon coating was prepared according to the following specific steps:

[0039] First step, sodium dodecyl sulfate (0.289 g, 1 mmol), IBVE (4.000 g, 40 mmol), GMA (1.472 g, 10 mmol) were added to 60 ml of deionized water and mixed while being dispersed using ultrasound for 30 min to obtain dispersion A;

[0040] ​Second step, 64 g of dispersion A from first step was added to a high pressure reactor, followed by the addition of NaHC03(0.400 g, 5 mmol), KPS (0.060 g, 0.2 mmol). The high pressure reactor was sealed and deoxygenated with 0.3 MPa of nitrogen for 30 min. Then, the high pressure reactor was degassed and reduced to 10 -2 mbar to remove oxygen to vacuum. CTFE monomer (15.000 g) was added by the double weighing method (i.e. the difference between the weight before and after the addition of CTFE gas). All polymerization processes were carried out in a 250 mL high pressure reactor equipped with a rupture disc (3000 psi), a pressure gauge, inlet and outlet valves, and a mechanical stirring paddle. The high pressure reactor was pressurized with 20 bar of nitrogen to check the sealing of the high pressure reactor. The whole reaction was carried out at 60 °C for 8 h under continuous stirring (stirring rate of 200 rpm). After the completion of the reaction, the high pressure reactor was cooled and degassed to obtain the aqueous FEVE fluorocarbon emulsion (FEVE G2).

[0041] Third step, the obtained emulsion was further sonicated for 40 min, the glass sheet substrates were thoroughly cleaned with alcohol and alkaline detergent, rinsed with deionized water and dried. The sonicated latex particles were coated on the dried glass sheets by drop coating method, and dried at 60 °C for 24 h to obtain the coating layer with a thickness of 50 ± 2 pm.

[0042] The FEVE G2 was tested by Fourier transform infrared spectroscopy (FTIR) using a German Tensor-27 spectrometer, and the results are shown in Figure 1 The absorption peaks at 2856 cm -1 and 2919 cm -1 are the stretching vibration peaks of saturated C-H bonds (-CH3and -CH2). The strong absorption peak at 1730 cm -1 is the stretching vibration of carbonyl (C=0) in GMA. The absorption peak at 854 cm -1 is due to the bending vibration of epoxy group (-CH(O)CH-), while the sharp absorption peak at 1282 cm -1 represents the stretching vibration peak of C-O in GMA. The strong absorption peak at 1115 cm -1 in the figure is derived from the stretching vibration of C-F in P(CTFE-co-IBVE). In addition, the particle size and its distribution of the FEVE G2 emulsion were tested by dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are shown in Figure 2 The particle size of the emulsion is 459 nm, and the distribution index is 0.121, indicating that the FEVE G2 emulsion has good stability. The adhesion properties of the FEVE G2 coating layer are as follows Figure 3The lap shear strength and tensile maximum force of the FEVEG2 coating were 0.823 MPa and 254.3 N, respectively, as shown. The hydrophobicity of the FEVEG2 coating was tested by measuring the contact angle with water, which was only 69°, as shown. Figure 5 The anticorrosion ability of the FEVEG2 coating was tested by a CHI-660E electrochemical workstation from Shanghai Chenhua, and the test results are shown in Table 2. Figure 6 The simulated impedance of the FEVEG2 coating was 3.1 x 10 6 Ω·cm 2 .

[0043] Example 4:

[0044] A waterborne fluorocarbon coating was prepared according to the following specific steps:

[0045] In the first step, sodium dodecyl sulfate (0.289 g, 1 mmol), IBVE (4.000 g, 40 mmol), and GMA (2.208 g, 15 mmol) were added to 60 ml of deionized water and mixed while being ultrasonically dispersed for 30 min to obtain dispersion A.

[0046] In the second step, 64 g of dispersion A from the first step was added to a high-pressure reaction kettle, and NaHCO3 (0.400 g, 5 mmol) and KPS (0.060 g, 0.2 mmol) were added separately. After the high-pressure kettle was sealed, it was deoxygenated with 0.3 MPa of nitrogen for 30 min, and then the high-pressure reaction kettle was degassed and depressurized to 10 -2 mbar to exclude oxygen to achieve a vacuum state. CTFE monomer (15.000 g) was added by the twice weighing method (i.e., the difference in weight before and after the addition of CTFE gas). All polymerization processes were carried out in a 250 mL high-pressure reaction kettle equipped with a bursting disc (3000 psi), a pressure gauge, inlet and outlet valves, and a mechanical stirring paddle. The high-pressure reaction kettle was pressurized with 20 bar of nitrogen to check the sealing of the high-pressure reaction kettle. The entire reaction was carried out at 60°C under continuous stirring (stirring rate of 200 rpm) for 8 h. After the reaction was completed, the high-pressure kettle was cooled and degassed to obtain an aqueous FEVE fluorocarbon emulsion (FEVEG3).

[0047] In the third step, the obtained emulsion was further ultrasonically dispersed for 40 min, and the glass sheet substrate was thoroughly cleaned with alcohol and alkaline detergent, rinsed with deionized water, and dried. The ultrasonically treated latex particles were coated on the dried glass sheet by drop coating, and the coating was dried at a constant temperature of 60°C for 24 h to obtain a coating with a thickness of 50 ± 2 μm.

[0048] The adhesion properties of the FEVEG3 coating are shown in Table 3. Figure 3The lap shear strength and tensile maximum force are 0.910 MPa and 281.8 N, respectively. Through Examples 2-4, we can see that the adhesion of the coating is improved from 0.69 MPa to 0.91 MPa as the GMA content increases, which indicates that GMA can greatly improve the adhesion of the coating to the substrate. This is because the epoxy groups in GMA can form a chemical adsorption layer with the substrate, which can improve the adhesion of the coating to the substrate. However, due to the presence of hydrophilic groups in GMA and vinyl ether, this will affect the hydrophobicity and corrosion resistance of the coating.

[0049] Example 5:

[0050] A water-based fluorocarbon coating was prepared, and the specific steps were as follows:

[0051] In the first step, FAS13 (0.510 g, 1 mmol), IBVE (4.000 g, 40 mmol), and GMA (1.472 g, 15 mmol) were added to 60 ml of deionized water and mixed while being ultrasonically dispersed for 30 min to obtain dispersion A;

[0052] In the second step, 64 g of dispersion A from the first step was added to a high-pressure reaction kettle, and NaHCO3 (0.400 g, 5 mmol) and KPS (0.060 g, 0.2 mmol) were added separately. After the high-pressure kettle was sealed, it was deoxygenated with 0.3 MPa of nitrogen for 30 min, then the high-pressure reaction kettle was degassed and reduced to 10 -2 mbar to exclude oxygen and achieve a vacuum state. CTFE monomer (15.000 g) was added by the double weighing method (i.e., the difference in weight before and after the addition of CTFE gas). All polymerization processes were carried out in a 250 mL high-pressure reaction kettle equipped with a bursting disc (3000 psi), a pressure gauge, inlet and outlet valves, and a mechanical stirring paddle. The high-pressure reaction kettle was pressurized with 20 bar of nitrogen to check its sealing. The entire reaction was carried out at 60°C with continuous stirring (stirring rate of 200 rpm) for 8 h. After the reaction was completed, the high-pressure kettle was cooled and degassed to obtain a water-based FEVE fluorocarbon emulsion (FEVEG2F1).

[0053] In the third step, the obtained emulsion was further ultrasonically dispersed for 40 min, and the glass substrate was thoroughly cleaned with alcohol and alkaline detergent, then washed with deionized water and dried. The ultrasonically treated latex particles were coated on the dried glass substrate by drop coating, and dried at 60°C for 24 h to obtain a coating with a thickness of 50±2 μm.

[0054] The FEVEG2F1 was tested by Fourier Transform Infrared Spectroscopy (FTIR) using a German Tensor-27 spectrometer, and the results are shown in Figure 1. Figure 1shown, 2856 cm -1 and 2919 cm -1 The strong absorption peak at 1730 cm -1 is the stretching vibration of carbonyl (C=O) in GMA. The absorption peak at 854 cm -1 is due to the bending vibration of epoxy group (-CH(O)CH-), while the sharp absorption peak at 1282 cm -1 represents the stretching vibration of C-O in GMA. The strong absorption peak at 1115 cm -1 in the figure is derived from the stretching vibration of C-F in P(CTFE-co-IBVE), while the absorption peak at 1080 cm -1 is caused by the stretching vibration of Si-O-Si in PFSQ. In addition, the particle size and its distribution of the FEVEG2F1 emulsion were tested by dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are shown in Figure 2 . The particle size of the emulsion is 501.3 nm, and the distribution index is 0.145, indicating that the FEVEG2F1 emulsion has good stability. The adhesion performance of the FEVEG2F1 coating is shown in Figure 3 , and the lap shear strength and tensile maximum force are 0.906 MPa and 283.7 N, respectively. The hydrophobicity of the FEVEG2F1 coating is shown in Figure 5 , and the contact angle with water is 97°. The corrosion resistance of the FEVEG2F1 coating is shown in Figure 6 , and the simulated impedance is 6.5 x 10 6 Ω·cm 2 .

[0055] Example 6:

[0056] Preparation of a water-based fluorocarbon coating, the specific steps are as follows:

[0057] First, FAS13 (1.020 g, 1 mmol), IBVE (4.000 g, 40 mmol), GMA (1.472 g, 15 mmol) were added to 60 ml of deionized water and mixed, and dispersed by ultrasonic wave for 30 min to obtain dispersion A;

[0058] Second, 64 g of dispersion A in the first step was added to a high-pressure reaction kettle, and then NaHCO3 (0.400 g, 5 mmol), KPS (0.060 g, 0.2 mmol) were added respectively. After the high-pressure kettle was closed, it was deoxygenated with 0.3 MPa of nitrogen for 30 min, and then the high-pressure reaction kettle was degassed, and the pressure was reduced to 10 -2A vacuum was achieved by removing oxygen from the atmosphere below mbar. CTFE monomer (15,000 g) was added using a double weighing method (i.e., weighing the weight difference before and after the addition of CTFE gas). All polymerization processes were carried out in a 250 mL high-pressure reactor equipped with a rupture disc (3000 psi), pressure gauge, inlet and outlet valves, and a mechanical stirrer. The reactor was pressurized with nitrogen at 20 bar to check its seal. The entire reaction was carried out at 60°C with continuous stirring (200 rpm) for 8 hours. After the reaction was complete, the reactor was cooled and degassed to obtain an aqueous FEVE fluorocarbon emulsion (FEVEG2F2).

[0059] The third step involves further ultrasonically dispersing the obtained emulsion for 40 minutes, thoroughly cleaning the glass substrate with alcohol and alkaline detergent respectively, rinsing with deionized water, and drying. The ultrasonically treated latex particles are then coated onto the dried glass slide using a drop-coating method and dried at 60°C for 24 hours to obtain a coating with a thickness of 50±2μm.

[0060] Fourier transform infrared (FTIR) spectroscopy was performed on FEVEG2F2 using a German Tensor-27 spectrometer. The results are as follows: Figure 1 As shown, 2856cm -1 and 2919cm -1 The absorption peak at 1730 cm⁻¹ is due to the stretching vibration of saturated CH bonds (-CH₃ and -CH₂). -1 The strong absorption peak at 854 cm⁻¹ is due to the stretching vibration of the carbonyl group (C=O) in GMA. -1 The absorption peak at 1282 cm⁻¹ is due to the bending vibration of the epoxy group (-CH(O)CH⁻), while the peak at 1282 cm⁻¹ is due to the bending vibration of the epoxy group (-CH(O)CH⁻). -1 The sharp absorption peak at 1115 cm⁻¹ represents the stretching vibration peak of CO in GMA. (See figure 1115 cm⁻¹) -1 The strong absorption peak at 1080 cm⁻¹ originates from the stretching vibration of CF in P(CTFE-co-IBVE), while the peak at 1080 cm⁻¹... -1 The absorption peak at that point is caused by the stretching vibration of Si-O-Si in PFSQ. Furthermore, the particle size and distribution of the FEVEG2F2 emulsion were measured using a dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are as follows: Figure 2 As shown in the figure, the emulsion has a particle size of 609.3 nm and a distribution index of 0.061, indicating that the FEVEG2F2 emulsion has good stability. The adhesion properties of the FEVEG2F2 coating are as follows: Figure 4 As shown, its lap shear strength and maximum tensile force are 0.970 MPa and 303.3 N, respectively. The hydrophobicity of the FEVEG2F2 coating is as follows: Figure 5 As shown, its contact angle with water is 123°. The corrosion resistance of the FEVEG2F2 coating is as follows:Figure 6 The simulated impedance is 1.05 x 10 7 Ω·cm 2 .

[0061] Example 7:

[0062] A water-based fluorocarbon coating was prepared according to the following specific steps:

[0063] In the first step, FAS13 (1.530 g, 1 mmol), IBVE (4.000 g, 40 mmol), and GMA (1.472 g, 15 mmol) were added to 60 ml of deionized water and mixed while being dispersed by ultrasonic waves for 30 min to obtain dispersion A;

[0064] In the second step, 64 g of dispersion A from the first step was added to a high-pressure reaction kettle, and NaHCO3 (0.400 g, 5 mmol) and KPS (0.060 g, 0.2 mmol) were added separately. After the high-pressure kettle was sealed, it was deoxygenated with 0.3 MPa of nitrogen for 30 min, and then the high-pressure reaction kettle was degassed and reduced to 10 -2 mbar to exclude oxygen to achieve a vacuum state. CTFE monomer (15.000 g) was added by the double weighing method (i.e., the difference in weight before and after the addition of CTFE gas was measured). All polymerization processes were carried out in a 250 mL high-pressure reaction kettle equipped with a bursting disc (3000 psi), a pressure gauge, inlet and outlet valves, and a mechanical stirring paddle. The high-pressure reaction kettle was pressurized with 20 bar of nitrogen to check the sealing of the high-pressure reaction kettle. The entire reaction was carried out at 60°C under continuous stirring (stirring rate of 200 rpm) for 8 h. After the reaction was completed, the high-pressure kettle was cooled and degassed to obtain a water-based FEVE fluorocarbon emulsion (FEVE G2F3).

[0065] In the third step, the obtained emulsion was further ultrasonically dispersed for 40 min, and the glass sheet substrate was thoroughly cleaned with alcohol and alkaline detergent, rinsed with deionized water, and dried. The ultrasonically treated latex particles were coated on the dried glass sheet by drop coating, and dried at 60°C for 24 h to obtain a coating layer with a thickness of 50 ± 2 μm.

[0066] The FEVE G2F3 was subjected to Fourier infrared spectroscopy (FTIR) testing using a German Tensor-27 spectrometer, and the results are shown in Figure 1 -1 2856 cm -1 and 2919 cm -1 The strong absorption peak at 1730 cm -1 is the stretching vibration of the carbonyl group (C=O) in GMA. The absorption peak at 854 cmThe absorption peak at 1282 cm -1 represents the stretching vibration peak of C-O in GMA. The strong absorption peak at 1115 cm -1 in the figure is due to the stretching vibration of C-F in P(CTFE-co-IBVE), while the absorption peak at 1080 cm -1 is caused by the stretching vibration of Si-O-Si in PFSQ. In addition, the particle size and its distribution of the FEVEG2F3 emulsion were tested by a dynamic light scattering particle size analyzer (XinSanSi, Shenzhen, China), and the results are shown in Figure 2 . The particle size of the emulsion is 673.4 nm, and the distribution index is 0.041, indicating that the FEVEG2F3 emulsion has good stability. The adhesion performance of the FEVEG2F3 coating is shown in Figure 5 , and the lap shear strength and tensile maximum force are 0.963 MPa and 301.7 N, respectively. The hydrophobicity of the FEVEG2F3 coating is shown in Figure 5 , and the contact angle with water is 131°. The corrosion resistance of the FEVEG2F3 coating is shown in Figure 6 , and the simulated impedance is 1.12×10 7 Ω·cm 2 .

[0067] According to Examples 3, 5-7, we can see that the contact angle of the coating is improved from 69° to 131°, which indicates that the hydrophobicity of the coating is greatly improved. This is because the network structure formed by the condensation of FAS13 can intertwine with the molecular chains of GMA, CTFE and IBVE, thereby blocking the contact of corrosive media (water, inorganic particles, organic media, etc.) with the substrate, and the improvement of the corrosion resistance of the coating is also due to this reason.

[0068] In summary, we successfully prepared a water-based FEVE fluorocarbon coating using a fluorosilane oligomer emulsion. The chemical adsorption layer formed by the epoxy groups introduced by GMA with the substrate can greatly improve the adhesion of the coating. In addition, the emulsifier fluorosilane oligomer can also condense to form a network, which can intertwine with the ternary molecular chain, effectively block the penetration of corrosive media, not only improve the hydrophobicity of the coating, but also improve the corrosion resistance of the coating. This work provides a simple method for preparing a hydrophobic, corrosion-resistant and high-adhesion coating.

[0069] The details of the present application are well known in the art.

Claims

1.A method for preparing a hydrophobic, corrosion-resistant, water-based FEVE fluorocarbon coating with high adhesion, characterized in that the method comprises the following steps: Step 1: adding perfluorooctyltriethoxysilane FAS13, compound A and GMA into deionized water, mixing and dispersing with ultrasonic waves for 10-40 min to obtain dispersion B; wherein 0.5-1.5 g of FAS13, 4-6 g of compound A and 0.5-1.5 g of GMA are added per 60 mL of deionized water; the compound A is one or more of vinyl ethers; Step 2: adding the dispersion B of Step 1 into a high-pressure reaction kettle, then adding NaHCO 3 and an initiator, respectively, and then adding CTFE monomers under an oxygen-free condition, and reacting the system under mechanical stirring at 40-70 ℃ for 6-9 h to obtain P(CTFE-co-IBVE-co-GMA)@PFSQ composite latex particle dispersion C; wherein the mass ratio of dispersion B to NaHCO 3 is 1:0.001-0.010; the mass ratio of the initiator to NaHCO 3 is 0.1-0.5:1; and the mass ratio of CTFE to NaHCO 3 is 25-45:1; Step 3: coating the dispersion C obtained in Step 2 on a substrate and drying at room temperature for 12-36 h to obtain a water-based FEVE fluorocarbon coating. 2.The method for preparing a hydrophobic, corrosion-resistant, water-based FEVE fluorocarbon coating with high adhesion according to claim 1, characterized in that in Step 1, the vinyl ether is isobutyl vinyl ether, hydroxybutyl vinyl ether, propyl vinyl ether or diethylene glycol monovinyl ether. 3.The method for preparing a hydrophobic, corrosion-resistant, water-based FEVE fluorocarbon coating with high adhesion according to claim 1, characterized in that in Step 2, the initiator is one or more of water-soluble initiators potassium persulfate, ammonium persulfate, azobisdimethylamidino hydrochloride and azobisdimethylimidazoline hydrochloride. The substrate is specifically a glass sheet, tinplate, leather, fabric or steel plate. 5.The method for preparing a hydrophobic, corrosion-resistant, water-based FEVE fluorocarbon coating with high adhesion according to claim 1, characterized in that the coating thickness is 40-60 μm. ​ ​ ​ ​ 4. The method of making a hydrophobic, corrosion resistant, high adhesion, waterborne FEVE fluorocarbon coating of claim 1 characterized by ​ ​

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