A modified PTFE coating and a method for preparing the same, a modified PTFE coating

Abstract

This invention relates to a modified PTFE coating and its preparation method, and to the field of coating technology. By weight, the modified PTFE coating comprises the following components: 8-12 parts PTFE coating and 0.3-0.8 parts filler. Based on existing PTFE coatings, this invention prepares a modified PTFE coating by incorporating specific fillers. The modified PTFE coating formed by this modified PTFE coating exhibits excellent resistance to alkali corrosion and scale prevention, providing a new approach for long-term scale prevention in tunnel engineering materials and possessing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of liquid silicone coating technology, and more particularly to a modified PTFE coating and its preparation method, and a modified PTFE coating layer. Background Technology

[0002] Drainage pipes in tunnel engineering are exposed to various scale-forming ions, such as calcium carbonate. 2+ CO3 2- HCO3 - These ions will form calcite scale, which adheres to the inner wall of the drainage pipe, gradually developing and eventually completely blocking it. This severely affects the service life of the tunnel drainage system and poses a threat to the structural safety of the tunnel. Because tunnel drainage pipes are difficult to inspect after construction, many engineers fail to realize that the appearance of tunnel cracks and water leakage is caused by high water pressure resulting from blocked drainage pipes and the inability of groundwater to drain properly. Compared with HVAC pipes and water and oil pipelines, the blockage of tunnel drainage pipes is often more severe. Since the tunnel lining material is Portland cement, groundwater seeps into the concrete and enters the drainage system, carrying a large number of scale-forming ions. At the same time, due to the hydration process of cement, the groundwater flowing into the tunnel drainage system creates a high pH environment conducive to calcite scale formation, promoting calcite scale formation while also causing corrosion and pollution to the pipes. Therefore, it is necessary to adopt scale-inhibiting technologies and materials to prevent calcite scale formation, delay alkaline corrosion, improve the service life of the tunnel drainage system, and ensure traffic safety. Commonly used chemical and physical anti-scaling methods are complex and ineffective. To solve the problem of scale buildup and blockage in tunnel drainage pipes, applying a protective coating with anti-scaling and anti-corrosion properties to the inner wall of the drainage pipe is an effective method.

[0003] Studies have shown that surface fouling is significantly reduced with decreasing surface energy. Many researchers have achieved self-cleaning and anti-fouling effects on coating surfaces by introducing fluorine and silicon elements. These coatings are characterized by low surface energy, high hydrophobicity, and certain lubricity. Among them, polytetrafluoroethylene (PTFE) is renowned for its excellent chemical inertness, solvent resistance, thermal stability, mechanical properties, and antifouling properties. Fluorine atoms in the PTFE layer molecules firmly bind the CC backbone to the inner layer, forming a low surface energy protective layer, giving PTFE significant hydrophobicity and lipophilicity. However, reducing the surface energy of the coating also reduces the affinity between liquids and solids, which in turn leads to limited chemical bonds within the matrix and weaker adhesion to the underlying substrate. Simultaneously, these coatings themselves are also soft and lack wear resistance. In tunnel engineering, the internal coating of pipes is prone to softening over time, and the surface of pipes with functional coatings is susceptible to varying degrees of damage. When the coating is damaged, the defective area often provides a favorable corrosive environment, leading to further peeling of the inner coating and pipe corrosion. Modifying PTFE for different application scenarios to meet usage requirements has become a research hotspot in recent years. Summary of the Invention

[0004] To address the above problems, this invention provides a modified PTFE coating and its preparation method, as well as a modified PTFE coating layer.

[0005] In a first aspect, the present invention provides a modified PTFE coating, wherein the modified PTFE coating comprises the following components in parts by weight:

[0006] 8-12 parts of PTFE coating and 0.3-0.8 parts of filler;

[0007] The method for preparing the filler includes the following steps:

[0008] ZrO2 was added to an anhydrous ethanol solution containing hydroxyethylidene diphosphonic acid, and then ultrasonically dispersed to obtain the first mixed solution.

[0009] The first mixed solution was dried until it was completely evaporated to obtain an intermediate.

[0010] The intermediate and an ethyl acetate solution containing lecithin were mixed to obtain a second mixed solution;

[0011] The second mixed solution was evaporated under reduced pressure until the solvent was completely evaporated, thus obtaining the filler.

[0012] Further, by weight, the modified PTFE coating comprises the following components:

[0013] 10 parts PTFE coating and 0.5 parts filler.

[0014] Furthermore, the PTFE coating includes product model Dongyue DF-331Z; the weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is (1.5-2.5):(0.3-0.8).

[0015] Furthermore, the weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is 2:0.5, and the weight percentage of hydroxyethylidene diphosphonic acid in the anhydrous ethanol solution is 3-8 wt%.

[0016] Furthermore, the weight percentage of hydroxyethylidene diphosphonic acid in the anhydrous ethanol solution is 5 wt%.

[0017] Furthermore, the drying operating conditions include a drying temperature of 55–65°C.

[0018] Furthermore, the weight ratio of the intermediate to the lecithin is (2-3):(0.3-0.8).

[0019] Further, the weight ratio of the intermediate to the lecithin is 2.5:0.5, and the weight percentage of lecithin in the ethyl acetate solution is 0.3-0.8 wt%. The working conditions for the vacuum evaporation include: temperature of 45-55℃, pressure of -0.1 MPa, and time of 1-2 h.

[0020] In a second aspect, the present invention provides a method for preparing the modified PTFE coating according to any one of the first aspects, the method comprising the following steps:

[0021] The filler is obtained;

[0022] The filler and PTFE coating are stirred and mixed to obtain the modified PTFE coating.

[0023] Thirdly, the present invention provides a modified PTFE coating, wherein the modified PTFE coating is prepared by using the modified PTFE coating described in any one of the first aspects or by using the preparation method described in any one of the second aspects.

[0024] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art:

[0025] This invention provides a modified PTFE coating and its preparation method, as well as a modified PTFE coating layer. Based on existing PTFE coatings, this invention prepares a modified PTFE coating by incorporating specific fillers. The modified PTFE coating formed by this modified PTFE coating exhibits excellent resistance to alkali corrosion and scale prevention capabilities, providing a new approach for long-term scale prevention in tunnel engineering materials and possessing broad application prospects. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a scanning electron microscope image of HEDP / ZrO2 in this invention.

[0029] Figure 2 This is a scanning electron microscope image of the LE-encapsulated ZrO2 / HEDP composite material in this invention.

[0030] Figure 3 The images show the infrared spectra of the Lecithin, ZrO2 / HEDP / lecithin, and ZrO2 / HEDP samples used in this invention.

[0031] Figure 4 These are the test results from the thermogravimetric analyzer used in this invention.

[0032] Figure 5 The results of the wettability test analysis of the coating in this invention are shown.

[0033] Figure 6 These are the adhesion performance test results of the coating in this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0036] In a first aspect, the present invention provides a modified PTFE coating, wherein the modified PTFE coating comprises the following components in parts by weight:

[0037] 8-12 parts of PTFE coating and 0.3-0.8 parts of filler;

[0038] The method for preparing the filler includes the following steps:

[0039] ZrO2 was added to an anhydrous ethanol solution containing hydroxyethylidene diphosphonic acid, and then ultrasonically dispersed to obtain the first mixed solution.

[0040] The first mixed solution was dried until it was completely evaporated to obtain an intermediate.

[0041] The intermediate and an ethyl acetate solution containing lecithin were mixed to obtain a second mixed solution;

[0042] The second mixed solution was evaporated under reduced pressure until the solvent was completely evaporated, thus obtaining the filler.

[0043] This invention provides a modified PTFE coating. Based on existing PTFE coatings, this invention prepares a modified PTFE coating by incorporating specific fillers. The modified PTFE coating formed by this modified PTFE coating exhibits excellent resistance to alkali corrosion and scale prevention capabilities, providing a new approach for long-term scale prevention in the field of tunnel engineering materials and possessing broad application prospects.

[0044] In this invention, "LE" means lecithin and "HEDP" means hydroxyethylidene diphosphonic acid.

[0045] In some specific embodiments, the modified PTFE coating comprises the following components, by weight:

[0046] 10 parts PTFE coating and 0.5 parts filler.

[0047] In some specific embodiments, the PTFE coating includes product model Dongyue DF-331Z; the weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is (1.5-2.5):(0.3-0.8).

[0048] In some specific embodiments, the weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is 2:0.5, and the weight percentage of hydroxyethylidene diphosphonic acid in the anhydrous ethanol solution is 3-8 wt%.

[0049] In some specific embodiments, the weight percentage of hydroxyethylidene diphosphonic acid in the anhydrous ethanol solution is 5 wt%.

[0050] In some specific embodiments, the drying operating conditions include a drying temperature of 55–65°C.

[0051] In some specific embodiments, the weight ratio of the intermediate to the lecithin is (2-3):(0.3-0.8).

[0052] In some specific embodiments, the weight ratio of the intermediate to the lecithin is 2.5:0.5, and the weight percentage of lecithin in the ethyl acetate solution is 0.3-0.8 wt%. The working conditions for the vacuum evaporation include: temperature of 45-55°C, pressure of -0.1 MPa, and time of 1-2 h.

[0053] In some specific embodiments, the weight percentage of lecithin in the ethyl acetate solution is 0.3-0.8 wt%, preferably 0.5 wt%; the working conditions for the vacuum evaporation include: a temperature of 45-55°C, preferably 50°C; a pressure of -0.1 MPa; and a time of 1-2 h, preferably 1 h.

[0054] In some specific embodiments, the preparation method of the above-mentioned LE-encapsulated ZrO2 / HEDP composite material includes the following steps:

[0055] First, 2g of ZrO2 was weighed and added to 10g of anhydrous ethanol solution containing 5wt% HEDP. The mixture was then ultrasonically dispersed for approximately 10 minutes to form a homogeneous solution. The solution was then placed in a vacuum drying oven at 60°C until completely evaporated, yielding an intermediate. Next, 2.5g of the intermediate was mixed with 100g of ethyl acetate solution containing 0.5wt% lecithin and transferred to a round-bottom flask. The mixture was rotary evaporated at 50°C and -0.1MPa for 1 hour to completely evaporate the organic solvent, yielding the LE-encapsulated ZrO2 / HEDP composite material.

[0056] Secondly, based on the same inventive concept, the present invention provides a method for preparing the modified PTFE coating according to any one of the first aspects, the method comprising the following steps:

[0057] The filler is obtained;

[0058] The filler and PTFE coating are stirred and mixed to obtain the modified PTFE coating.

[0059] Thirdly, the present invention provides a modified PTFE coating, wherein the modified PTFE coating is prepared by using the modified PTFE coating described in any one of the first aspects or by using the preparation method described in any one of the second aspects.

[0060] It should be noted that, unless otherwise specified or specifically described, the modified PTFE coating and its preparation method provided in the embodiments of the present invention, as well as the raw material components involved in the modified PTFE coating, can be directly purchased from commercially available products or made in-house according to existing preparation methods; at the same time, unless otherwise specified or specifically described, the operation steps involved in the preparation method can be carried out according to existing processes.

[0061] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0062] Example 1

[0063] This example provides a packing material, and the preparation method of the packing material includes the following steps:

[0064] First, 2g of ZrO2 was weighed and added to 10g of anhydrous ethanol solution containing 5wt% HEDP. The solution was then ultrasonically dispersed for approximately 10 minutes to form a homogeneous solution. The solution was then placed in a vacuum drying oven at 60°C until completely evaporated, yielding an intermediate. Next, 2.5g of the intermediate was mixed with 100g of ethyl acetate solution containing 0.5wt% lecithin and transferred to a round-bottom flask. The mixture was rotary evaporated at 50°C and -0.1MPa for 1 hour to completely evaporate the organic solvent, yielding the filler material.

[0065] Example 2

[0066] This example provides a filler and its preparation method, which differs from Example 1 only in that the weight ratio of ZrO2 and hydroxyethylidene diphosphonic acid is 1.5:0.3, and the weight ratio of the intermediate and lecithin is 2:0.3.

[0067] Example 3

[0068] This example provides a filler and its preparation method, which differs from Example 1 only in that the weight ratio of ZrO2 and hydroxyethylidene diphosphonic acid is 2.5:0.8, and the weight ratio of the intermediate and lecithin is 3:0.8.

[0069] Example 4

[0070] This example provides a modified PTFE coating, which, by weight, comprises the following components:

[0071] 10 parts PTFE coating and 0.5 parts filler;

[0072] The PTFE coating product mentioned is Dongyue DF-331Z;

[0073] The packing material used is the one obtained in Example 1.

[0074] The preparation method of the above-mentioned modified PTFE coating includes the following steps: mixing and dispersing 10g of PTFE solution with 0.5g of filler evenly to form a modified PTFE coating.

[0075] Test case

[0076] This example demonstrates the performance of the modified PTFE coating of Example 4 obtained by applying the filler obtained in Example 1 to a commercially available PTFE (polytetrafluoroethylene) coating solution (product model: Dongyue DF-331Z).

[0077] 1) The coating preparation process includes the following steps: 1) Mix 10g of PTFE solution with 0.5g of filler and disperse evenly to form a modified PTFE coating. 2) Disperse the commercially available PTFE (polytetrafluoroethylene) coating evenly and spray it with a spray gun at a high temperature of 60℃. The spraying pressure is 0.5±0.05MPa and the spraying height is 15±0.5cm. The pure coating is marked as PTFE. The modified coating from step 1) is sprayed onto the surface of the PE substrate using the same method and marked as a modified PTFE coating. Finally, the sprayed coating is heated at 60℃ for 12h to form a cured coating with a thickness of 60±3μm.

[0078] 2) The QCMD wafer sensor fabrication process includes the following steps: The QCMD wafer sensor model is AC5AP14. Pure PTFE and modified PTFE coatings are sprayed onto the wafer surface using the same spraying method as the coating preparation. The prepared wafer coating surfaces are then subjected to alkaline corrosion by contacting a 0.1 mol / L NaOH solution at 24°C and 50% humidity for 28 days. These results are recorded as "modified PTFE after corrosion" (i.e., QCMD wafer sensor with modified PTFE coating) and "PTFE after corrosion" (i.e., QCMD wafer sensor with pure PTFE coating), respectively.

[0079] 3) Scanning electron microscopy was used to analyze the morphology and elemental distribution of calcium carbonate in the filler particles (i.e., LE-encapsulated ZrO2 / HEDP composite material) and the coating surface. Fourier transform infrared spectroscopy was used to characterize the surface properties of the filler. Thermogravimetric analysis was used to confirm the encapsulation of ZrO2 / HEDP by lecithin. The anti-scaling performance of the modified PTFE coating was tested using a dissipative quartz crystal microbalance. The coating thickness was tested using an ultrasonic coating thickness gauge. The slow-release performance and durability of the modified coating were tested using an immersion method. The corrosion resistance was tested using an electrochemical workstation (CHI760F). The adsorption strength of the coating was tested using a cross-cut adhesion tester according to ISO2409-1992 at an environment of 24℃ and 50% relative humidity.

[0080] The test results are as follows:

[0081] Compared to lecithin-encapsulated HEDP / ZrO2 ( Figure 2 ), Figure 1 The HEDP / ZrO2 filler in this material has a significantly smaller diameter, is granular, and loosely distributed. It consists of two different material structures, with HEDP particles dotting the surface of spherical ZrO2 particles. For example... Figure 2 As shown, after lecithin encapsulates HEDP / ZrO2, the particle volume increases, and they accumulate in an irregular bubble shape, exhibiting a distinct lecithin membrane structure. The surface of the lecithin membrane reveals that the internally encapsulated HEDP / ZrO2 structure presents as granular protrusions, structurally confirming the successful encapsulation of HEDP / ZrO2 by lecithin. Elemental analysis of the samples shows that the prepared HEDP / ZrO2 is uniformly distributed, a prerequisite for the successful encapsulation of both substances by LE. The internal elements of the lecithin membrane structure after LE encapsulation possess characteristics of both HEDP and ZrO2, further confirming the successful encapsulation of HEDP / ZrO2 by LE.

[0082] The infrared spectra of Lecithin (pure lecithin), ZrO2 / HEDP / lecithin (LE-encapsulated ZrO2 / HEDP composite material), and ZrO2 / HEDP samples are shown in the figure. Figure 3 In b, the bands are 1710, 2910, and 2950-3050 cm. -1 These belong to the stretching vibrations of C=O in the -CO-O- group, the stretching vibrations of -CH2-, and the asymmetric bending vibrations of -C=CH, respectively. Figure 3 These three sets of peaks can be observed in a and c, but... Figure 3 It cannot be observed in b. Figure 3 c shows 920-1120 and 1430-1490cm -1The strong and broad absorption peaks at these locations are attributed to the asymmetric bending vibrations of the P-(OH)2 and -CH3 bonds in HEDP, respectively. These two sets of peaks can be observed in Figures b and c, but... Figure 3 Not observable in a. FTIR confirmed the assembly of ZrO2 / HEDP / lecithin.

[0083] The thermal stability of each component and the compound was tested using a thermogravimetric analyzer, and the results are as follows: Figure 4 As shown, the decomposition temperature of HEDP is 169.6℃~343.7℃ (range I), as... Figure 4 As shown, the decomposition temperature of lecithin is 230.5–490.1℃ (range II). Compared with pure lecithin, the lecithin / ZrO2 intermediate has a slope peak at 449.8℃, where the slope peak at 449.8℃ corresponds to… Figure 4 The slope peak at 387.9℃ is due to lecithin being coated on the ZrO2 surface in a film-like state, which alters the heat-receiving area and thus changes the decomposition temperature range. Furthermore, compared to pure lecithin, Figure 4 A new decomposition temperature range of 512.5–555.1℃ influenced by ZrO2 was added, with a slope peak at 535.8℃, corresponding to which... Figure 4 The decomposition temperature range is 493.2–573.7℃ (range III), with a slope peak of 517.5℃. The above analysis shows that HEDP mainly decomposes in temperature range I, while lecithin mainly decomposes in temperature range II. This thermal stability confirms the successful encapsulation of HEDP / ZrO2 by lecithin.

[0084] 4) Coating wettability test analysis: The inner wall coating of the drainage pipe will come into contact with groundwater during actual use. Groundwater may penetrate the tiny pores, cracks, and defects on the coating surface, reaching the drainage pipe substrate and causing corrosion and scaling. Therefore, the coating needs to be hydrophobic. The typical contact angle of PTFE varies within the range of 90-108°, classifying it as a hydrophobic material. This experiment tested the contact angle of the PTFE coating before and after the addition of slow-release filler, and also tested the change in the contact angle of the PTFE coating after 28 days of alkaline corrosion with a 1 mol / L sodium hydroxide solution at 24℃ and 50% humidity. Figure 5As shown, the initial contact angle of the PTFE coating was 107.8°, which decreased to 96.5° after alkaline corrosion. The initial contact angle of the PTFE coating with slow-release filler was 109.1°, which slightly decreased to 107.8° after alkaline corrosion. Compared with the pure PTFE coating, the addition of slow-release filler resulted in a rougher surface structure, thus improving the initial contact angle. Although PTFE is chemically inert, alkaline corrosion causes structural changes and aging on the PTFE surface. Simultaneously, the weakened adhesion between the PTFE coating and the PE substrate damages the coating's integrity, reducing its hydrophobicity. The incorporation of ZrO2 in the filler effectively improves the strength and hardness of the PTFE coating, enhancing its alkali resistance. Lecithin reduces the surface tension of the PTFE coating, allowing it to better bond with the PE surface and enhancing its adhesion. Therefore, the PTFE coating with slow-release filler exhibits a smaller change in contact angle after alkaline corrosion, enabling it to maintain its hydrophobicity in alkaline environments for extended periods.

[0085] 5) Coating adhesion performance test: The adhesion of the coating was tested using the cross-cut adhesion test, with a blade cutting speed of 30 mm / s. The results are as follows: Figure 6 As shown, from Figure 6 As can be seen, the coating adhesion is good, with no peeling at the edges and intersections of the scribed lines. The pure PTFE coating exhibits peeling, covering an area of ​​approximately xx%. This is because the choline and glycerophosphate in LE increase the adhesion of PTFE to the PE substrate, making the coating denser.

[0086] 6) Analysis of Coating Anti-fouling Performance Based on QCM-D: Quartz crystal microbalance dissipation (QCMD) can non-invasively monitor the interface between the sensor and the surrounding medium, detailing interfacial mass deposition, conformational evolution, solvation, and viscoelasticity. This method is widely used in research on nanoparticle deposition, vesicle fusion, interfacial bonding and adsorption, phase transition, and reaction kinetics. Test results show that before alkaline corrosion, the frequency change value of modified PTFE eventually stabilized at approximately -45.89 Hz, with an adsorbed mass of approximately 344.91 ng / cm², while the frequency change value of pure PTFE stabilized at approximately -63.41 Hz, with an adsorbed mass of approximately 476.58 ng / cm². Compared with pure PTFE, the anti-fouling performance of modified PTFE improved by approximately 38.18%. After alkaline corrosion, the frequency change value of modified PTFE stabilized at approximately -48.49 Hz, with an adsorbed mass of approximately 364.45 ng / cm², and the anti-fouling ability decreased by 5.67% compared to before alkaline corrosion. After alkaline corrosion, the frequency of pure PTFE changed continuously in three stages, reaching a value of -85.25 Hz by 13 hours. Compared with before corrosion, its anti-scaling ability decreased by approximately 34.44%, and compared with modified PTFE, the anti-scaling ability was about 75.81% lower. This shows that the addition of filler not only improves the anti-scaling ability but also maintains excellent anti-scaling performance after alkaline corrosion. PTFE coatings themselves have strong resistance to alkaline corrosion; however, after alkaline corrosion, the anti-scaling performance of pure PTFE coatings decreases significantly. This may be because long-term alkaline environments can cause the coating to detach or peel off from the substrate, thereby damaging the integrity of the coating and leading to a decrease in its anti-scaling performance. The addition of filler significantly improves the adhesion between the PTFE coating and the PE substrate and its own strength, ensuring the long-term integrity of the coating. Therefore, modified PTFE can also maintain long-term anti-scaling performance in alkaline corrosive environments.

[0087] 7) Anti-scaling mechanism of the coating: Based on the above test results, the modified PTFE coating exhibits excellent slow-release performance, corrosion resistance, adhesion performance, and anti-scaling performance. The main reasons are as follows: When a slow-release PTFE coating with lecithin-encapsulated filler is applied to the inner wall of a PE pipe, the HEDP in the surface filler is slowly released after the coating comes into contact with groundwater. Since groundwater is rich in substances such as calcium... 2+ CO3 2-HEDP, an anti-scaling ion, forms a complex with calcium ions in the water, thus preventing calcium carbonate precipitation. Furthermore, PTFE itself is hydrophobic, possessing a certain degree of physical anti-scaling ability. The addition of slow-release fillers increases the surface roughness of the coating, thereby enhancing its hydrophobicity and further improving its physical anti-scaling performance. The ZrO2 incorporated into the filler acts as a reinforcing aggregate; its strong alkali resistance reduces alkaline corrosion during long-term service, significantly improving coating durability. Due to PTFE's inherent hydrophobicity and low surface energy, its adhesion to PE surfaces is poor. As a surfactant, the addition of lecithin reduces the surface tension of the PTFE coating, improving adhesion through interaction with the PE surface, allowing PTFE to better bond with the PE surface.

[0088] In summary, this invention provides a modified PTFE coating and its preparation method, as well as a modified PTFE coating, which, after incorporating PTFE, produces a long-lasting anti-corrosion and anti-scaling coating sample. This coating maintains high durability, alkali resistance, and long-lasting anti-scaling performance under alkaline conditions. Because lecithin improves the adhesion between PTFE and the PE substrate, the modified coating's adhesion meets international standards in the cross-cut adhesion test, indicating that the modified coating can be stably adsorbed on the PE substrate. The slow-release properties of lecithin allow the coating to slowly release HEDP scale inhibitor upon contact with groundwater. With long-term groundwater erosion, the scale inhibitor inside the coating is also released, significantly improving the long-lasting anti-scaling performance of the coating from a chemical anti-scaling perspective. The incorporation of ZrO2 into the filler slightly improves the surface roughness of the coating, enhances the hydrophobicity of the PTFE coating, and improves its physical anti-scaling properties. The high hardness and strength of ZrO2 enhance the strength of the PTFE coating. Simultaneously, ZrO2's strong alkali resistance ensures the coating remains undamaged and maintains long-term anti-scaling capabilities under alkaline corrosive environments. QCMD test results show that the modified coating incorporating slow-release filler exhibits excellent alkaline corrosion resistance and anti-scaling capabilities. The development of this new material provides a novel approach to long-term anti-scaling in tunnel engineering materials and has broad application prospects.

[0089] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0090] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A modified PTFE coating, characterized in that, The modified PTFE coating, by weight, comprises the following components: 8-12 parts PTFE coating and 0.3-0.8 parts filler; The method for preparing the filler includes the following steps: ZrO2 was added to an anhydrous ethanol solution containing hydroxyethylidene diphosphonic acid, and then ultrasonically dispersed to obtain the first mixed solution. The first mixed solution was dried until it was completely evaporated to obtain an intermediate. The intermediate was mixed with an ethyl acetate solution containing lecithin to obtain a second mixed solution; The second mixed solution was subjected to vacuum evaporation until the solvent was completely evaporated, thus obtaining the filler. The product model of the PTFE coating is Dongyue DF-331Z; the weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is (1.5~2.5):(0.3~0.8). The weight percentage of hydroxyethylidene diphosphonic acid in the anhydrous ethanol solution is 5 wt%. The weight ratio of the intermediate to the lecithin is (2~3):(0.3~0.8).

2. The modified PTFE coating according to claim 1, characterized in that, The modified PTFE coating, by weight, comprises the following components: 10 parts PTFE coating and 0.5 parts filler.

3. The modified PTFE coating according to claim 1, characterized in that, The weight ratio of ZrO2 to hydroxyethylidene diphosphonic acid is 2:0.

5.

4. The modified PTFE coating according to claim 1, characterized in that, The drying working conditions parameters include: drying temperature of 55~65℃.

5. The modified PTFE coating according to claim 1, characterized in that, The weight ratio of the intermediate to the lecithin is 2.5:0.5, and the weight percentage of lecithin in the ethyl acetate solution is 0.3~0.8 wt%. The operating conditions for the reduced pressure evaporation include: a temperature of 45~55℃, a pressure of -0.1Mpa, and a time of 1~2h.

6. A method for preparing the modified PTFE coating according to any one of claims 1 to 5, characterized in that, The preparation method of the modified PTFE coating includes the following steps: The filler is obtained; The filler and PTFE coating are stirred and mixed to obtain the modified PTFE coating.

7. A modified PTFE coating, characterized in that, The modified PTFE coating is prepared using the modified PTFE coating according to any one of claims 1 to 5 or the modified PTFE coating prepared by the preparation method according to claim 6.

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