Self-drying hydrophobic coating, preparation method thereof, and steel bridge

Abstract

This application discloses a self-drying hydrophobic coating, its preparation method, and a steel bridge, relating to the field of bridge technology. The raw materials include resin, silane-modified hydrophobic nanoparticles, and a solvent, wherein: at least a portion of the silane-modified hydrophobic nanoparticles are embedded within the pores of a network structure formed by the resin; the resin includes at least one of thermoplastic polyurethane, aldehyde-ketone resin, terpene resin, and polyvinyl chloride; the silane-modified hydrophobic nanoparticles include at least one of silica, mica, wollastonite, kaolin, and glass flakes. By selecting a non-reactive, high-hardness, high-adhesion resin, the resin can fully swell in the solvent, coating the silane-modified hydrophobic nanoparticles. After coating the substrate surface, it rapidly solidifies into a film as the solvent evaporates, thus forming a superhydrophobic coating without requiring additional curing reaction time. The use of silane-modified hydrophobic nanoparticles enhances the coating strength and improves the adhesion between the resin matrix and the nanoparticles.

Description

Technical Field

[0001] This application relates to the field of bridge technology, and in particular to a self-drying hydrophobic coating, its preparation method, and a steel bridge. Background Technology

[0002] Bridges, as vital transportation infrastructure, play a crucial role in regional economic development and people's lives. However, in unique environments such as oceans and plateaus, bridge steel structures face severe corrosion challenges. Marine environments are rich in salt and moisture, while plateau regions may experience strong ultraviolet radiation and large temperature differences, all of which accelerate the corrosion process of bridge steel structures. Traditional protective measures for bridge steel structures often have limitations and cannot provide long-term effective protection. Summary of the Invention

[0003] This application provides a self-drying hydrophobic coating, its preparation method, and a steel bridge to address the limitations of existing protective measures, which often fail to provide long-term effective protection.

[0004] In a first aspect, this application provides a self-drying hydrophobic coating, the raw materials of which include resin, silane-modified hydrophobic nanoparticles, and solvent, wherein:

[0005] At least a portion of the silane-modified hydrophobic nanoparticles are embedded within the pores of the resin-formed mesh structure.

[0006] The resin includes at least one of thermoplastic polyurethane, aldehyde-ketone resin, terpene resin and polyvinyl chloride;

[0007] The silane-modified hydrophobic nanoparticles include at least one of silica, mica, wollastonite, kaolin, and glass flakes.

[0008] This application utilizes a non-reactive, high-hardness, high-adhesion resin. The resin can fully swell in a solvent, encapsulating silane-modified hydrophobic nanoparticles. After coating the substrate surface, it rapidly cures into a film as the solvent evaporates, forming a superhydrophobic coating without requiring additional curing time. The use of silane-modified hydrophobic nanoparticles enhances the coating strength and improves the adhesion between the resin matrix and the nanoparticles. This allows the hydrophobic nanoparticles to easily adhere and embed within the macromolecular network structure, thereby strengthening the adhesion between the nanoparticles and the resin matrix, ultimately improving the overall strength of the coating and extending its service life.

[0009] It should be noted that, in order to further improve the adhesion between silane-modified hydrophobic nanoparticles and resin, long-chain silane coupling agents can be added to the coating, so that the silane-modified hydrophobic nanoparticles are more firmly fixed to the coating, reducing coating delamination and improving the service life of the coating.

[0010] In some embodiments, the silane-modified hydrophobic nanoparticles include silane-modified hydrophobic nanoparticles of a first particle size and silane-modified hydrophobic nanoparticles of a second particle size, wherein:

[0011] The first particle size is 0.5–5 μm; and / or,

[0012] The second particle size is 10–50 nm; and / or,

[0013] The mass ratio of the first-size silane-modified hydrophobic nanoparticles to the second-size silane-modified hydrophobic nanoparticles is 1:(1.5-4).

[0014] Using silane-modified hydrophobic nanoparticles of different particle sizes can improve coating strength and the adhesion between the hydrophobic nanoparticles and the resin, thereby enhancing the hydrophobic properties of the coating. When the mass ratio of the first-size silane-modified hydrophobic nanoparticles to the second-size silane-modified hydrophobic nanoparticles is within this range, a portion of the silane-modified hydrophobic nanoparticles is encapsulated within the three-dimensional network structure formed by the resin, while another portion remains exposed outside the resin-formed three-dimensional network structure, thus improving the hydrophobic properties.

[0015] In some embodiments, the silane modifier for the silane-modified hydrophobic nanoparticles includes at least one selected from perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane, and perfluorododecyltrichlorosilane. Using the above-mentioned silane modifier can improve the dispersion performance and uniformity of the hydrophobic nanoparticles in the resin, while also enhancing the adhesion between the hydrophobic nanoparticles and the resin.

[0016] In some embodiments, the resin further includes at least one selected from chlorinated ether resin, perchlorinated vinyl, acrylic resin, and chlorinated vinyl acetate. Adding at least one of the above resins can improve the coating's anti-aging properties and salt spray resistance.

[0017] In some embodiments, the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:(1.5-2). This mass ratio can improve the proportion of silane-modified hydrophobic nanoparticles in the coating, improve the adhesion between the resin and nanoparticles, and reduce the problem of excessive resin causing the nanoparticles to be completely coated, leading to the failure of the surface superhydrophobic properties.

[0018] Secondly, this application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0019] The resin and solvent are mixed and swollen to form a three-dimensional network structure.

[0020] A self-drying hydrophobic coating is obtained by mixing silane-modified hydrophobic nanoparticles with a mixture.

[0021] By mixing resin and solvent, allowing them to swell and form a macromolecular-confined three-dimensional network structure, and then mixing silane-modified hydrophobic nanoparticles with this mixture, a dry-type hydrophobic coating is obtained. This allows the silane-modified hydrophobic nanoparticles to be embedded in the pores of the resin-formed three-dimensional network structure, thereby enhancing the adhesion between the nanoparticles and the resin, and ultimately improving the overall strength of the coating. Utilizing a molecular interpenetration mechanism, the coating's anti-aging properties are improved, enhancing both its strength and durability.

[0022] In some embodiments, the mixture in which the resin and solvent are mixed, swollen, and form a three-dimensional network structure is:

[0023] The swelling time is 20–30 hours. Within this range, the swelling time and rate allow the resin and solvent to mix and swell, forming a mixture with a macromolecular confined three-dimensional network structure. This is beneficial for the dispersion and bonding of silane-modified hydrophobic nanoparticles, and can improve the strength and durability of the coating.

[0024] In some embodiments, the preparation method of the silane-modified hydrophobic nanoparticles includes the following steps:

[0025] Hydrophobic nanoparticles were activated and then mixed with a solvent to obtain a suspension.

[0026] The suspension was mixed with the catalyst and silane modifier, centrifuged, and the solid phase was collected to obtain silane-modified hydrophobic nanoparticles.

[0027] By activating hydrophobic nanoparticles and then modifying them with silane modifiers under a catalyst, silane groups can be grafted onto the surface of the hydrophobic nanoparticles. These groups can then combine with the silanes in the coating, improving the bonding strength between the hydrophobic nanoparticles and the resin. This allows some of the hydrophobic nanoparticles to be fixed inside the coating to enhance durability, while others are exposed in the coating to improve hydrophobic properties.

[0028] Thirdly, this application proposes a steel bridge with a hydrophobic coating on its surface, the hydrophobic coating being applied by the self-drying hydrophobic coating described in the first aspect.

[0029] In some embodiments, the coating thickness is 20 μm to 200 μm. This thickness range improves the adhesion between the coating and the bridge, and also provides better corrosion resistance to the bridge; and / or,

[0030] In the coating, at least a portion of the silane-modified hydrophobic nanoparticles are exposed within the resin-formed network coating. This exposure of at least a portion of the silane-modified hydrophobic nanoparticles within the resin-formed network coating ensures the hydrophobic properties of the coating and improves the service life of the bridge. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a SEM image of silane-modified hydrophobic nanoparticles in the self-drying hydrophobic coating of Example 1 of this application.

[0033] Figure 2 This is a SEM image of the self-drying hydrophobic coating of Example 1 of this application.

[0034] Figure 3 This is an optical image of the surface of the self-drying hydrophobic coating of Embodiment 1 of this application.

[0035] Figure 4 This is a side view of the contact angle and roll-off angle of the self-drying hydrophobic coating surface in Embodiment 1 of this application.

[0036] Figure 5 This is a schematic diagram of the wear test of the self-drying hydrophobic coating of Embodiment 1 of this application.

[0037] Figure 6 The change in contact angle with the number of wear cycles in the wear test of the self-drying hydrophobic coating of Example 1 of this application.

[0038] Figure 7 This is a cross-cut test result of the self-drying hydrophobic coating of Example 1 of this application.

[0039] Figure 8 This is a comparison diagram of the self-drying hydrophobic coating of Example 1 of this application in its initial state, after 500 hours of aging, and after 1000 hours of aging.

[0040] Figure 9 This is a side view of the contact angle and roll-off angle of the self-drying hydrophobic coating of Comparative Example 1 of this application after aging for 1000 hours. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Bridges, as vital transportation infrastructure, play a crucial role in regional economic development and people's lives. However, in unique environments such as oceans and plateaus, bridge steel structures face severe corrosion challenges. Marine environments are rich in salt and moisture, while plateau regions may experience strong ultraviolet radiation and large temperature differences, all of which accelerate the corrosion process of bridge steel structures. Traditional protective measures for bridge steel structures often have limitations and cannot provide long-term effective protection. Developing an efficient and reliable method for protecting bridge steel structures has become an urgent priority.

[0043] The application of superhydrophobic coatings is limited by surface strength and durability, making it difficult to meet the requirements of long-term industrial applications. In aerospace, energy, and construction fields, surfaces are exposed to harsh working environments such as dust, rain, snow, and ultraviolet radiation, leading to severe wear and tear, causing surface dysfunction, negatively impacting equipment operation, and even threatening equipment safety. Laser ablation can be used to construct micro / nano structures on rigid substrates such as metals, or to construct rigid structures and fill them with hydrophobic nanoparticles to improve surface strength. However, this method is complex and difficult to apply on a large scale. Pre-laying reinforcing structures, such as fiberglass cloth or carbon fiber mesh, on the substrate surface before spraying / brushing a hydrophobic coating can improve the strength of the hydrophobic outer layer. However, laying reinforcing structures on complex-shaped components is complex, and the resulting coating thickness is relatively thick to ensure proper adhesion. Another method involves constructing a resin layer on the substrate and then laying hydrophobic nanoparticles on the surface while the coating is in a semi-cured state. First, hydrophobic nanoparticles are prepared, then blended with resin to form a coating. After adding a curing agent, a superhydrophobic surface is prepared by spraying / brushing. Both methods can significantly extend the service life of the superhydrophobic surface and ensure long-lasting protection of the substrate. However, the synthesis of hydrophobic nanoparticles and the preparation of the coating must be carried out in multiple steps during the preparation process. In addition, in the preparation strategy of hydrophobic particles and resin mixture, the resin curing time is often long, and even heat treatment is required. During this process, the coating is extremely fragile and easily affected by rainwater, moisture, etc., resulting in poor curing effect and affecting the coating performance and durability. With the increasing demand for bridge operation and maintenance, as well as waterproofing and antifouling, how to provide low-cost, efficient, and durable liquid media isolation methods for bridge structures, and provide effective media isolation protection for bridge structures to cope with extreme climatic environments such as wind, rain, snow, and ice, has become a key research focus.

[0044] In view of this, this application provides a self-drying hydrophobic coating, its preparation method, and a steel bridge to solve the problem that existing protective measures often have certain limitations and cannot provide long-term effective protection.

[0045] In a first aspect, this application provides a self-drying hydrophobic coating, the raw materials of which include resin, silane-modified hydrophobic nanoparticles, and solvent, wherein:

[0046] At least a portion of the silane-modified hydrophobic nanoparticles are embedded within the pores of the resin-formed mesh structure.

[0047] The resin includes at least one of thermoplastic polyurethane, aldehyde-ketone resin, terpene resin and polyvinyl chloride;

[0048] The silane-modified hydrophobic nanoparticles include at least one of silica, mica, wollastonite, kaolin, and glass flakes.

[0049] This application utilizes a non-reactive, high-hardness, high-adhesion resin. The resin can fully swell in a solvent, encapsulating silane-modified hydrophobic nanoparticles. After coating the substrate surface, it rapidly cures into a film as the solvent evaporates, forming a superhydrophobic coating without requiring additional curing time. The use of silane-modified hydrophobic nanoparticles enhances the coating strength and improves the adhesion between the resin matrix and the nanoparticles. This allows the hydrophobic nanoparticles to easily adhere and embed within the macromolecular network structure, thereby strengthening the adhesion between the nanoparticles and the resin matrix, ultimately improving the overall strength of the coating and extending its service life.

[0050] It should be noted that, in order to further improve the adhesion between silane-modified hydrophobic nanoparticles and resin, long-chain silane coupling agents can be added to the coating, so that the silane-modified hydrophobic nanoparticles are more firmly fixed to the coating, reducing coating delamination and improving the service life of the coating.

[0051] In conjunction with the first aspect, in some embodiments provided in this application, the silane-modified hydrophobic nanoparticles include silane-modified hydrophobic nanoparticles with a first particle size and silane-modified hydrophobic nanoparticles with a second particle size, wherein: the first particle size is 0.5 to 5 μm.

[0052] In conjunction with the first aspect, in some embodiments provided in this application, the silane-modified hydrophobic nanoparticles include silane-modified hydrophobic nanoparticles with a first particle size and silane-modified hydrophobic nanoparticles with a second particle size, wherein the second particle size is 10-50 nm.

[0053] In conjunction with the first aspect, in some embodiments provided in this application, the silane-modified hydrophobic nanoparticles include silane-modified hydrophobic nanoparticles of a first particle size and silane-modified hydrophobic nanoparticles of a second particle size, wherein the mass ratio of the silane-modified hydrophobic nanoparticles of the first particle size to the silane-modified hydrophobic nanoparticles of the second particle size is 1:(1.5-4).

[0054] Using silane-modified hydrophobic nanoparticles of different particle sizes can improve coating strength and the adhesion between the hydrophobic nanoparticles and the resin, thereby enhancing the hydrophobic properties of the coating. When the mass ratio of the first-size silane-modified hydrophobic nanoparticles to the second-size silane-modified hydrophobic nanoparticles is within this range, a portion of the silane-modified hydrophobic nanoparticles is encapsulated within the three-dimensional network structure formed by the resin, while another portion remains exposed outside the resin-formed three-dimensional network structure, thus improving the hydrophobic properties.

[0055] In conjunction with the first aspect, in some embodiments provided in this application, the silane modifier for the silane-modified hydrophobic nanoparticles includes at least one selected from perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane, and perfluorododecyltrichlorosilane. Using the above-mentioned silane modifier can improve the dispersion performance and uniformity of the hydrophobic nanoparticles in the resin, while also enhancing the adhesion between the hydrophobic nanoparticles and the resin.

[0056] In conjunction with the first aspect, in some embodiments provided in this application, the resin further includes at least one selected from chlorinated ether resin, perchlorinated vinyl, acrylic resin, and chlorinated vinyl acetate. Adding at least one of the above resins can improve the coating's anti-aging properties and salt spray resistance.

[0057] In conjunction with the first aspect, in some embodiments provided in this application, the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:(1.5-2). This mass ratio of resin to silane-modified hydrophobic nanoparticles within this range can improve the mass proportion of the silane-modified hydrophobic nanoparticles in the coating, improve the adhesion between the resin and the nanoparticles, and reduce the problem of the surface superhydrophobic properties failing due to excessive resin causing the nanoparticles to be completely coated with resin.

[0058] Secondly, this application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0059] The resin and solvent are mixed and swollen to form a three-dimensional network structure.

[0060] A self-drying hydrophobic coating is obtained by mixing silane-modified hydrophobic nanoparticles with a mixture.

[0061] By mixing resin and solvent, allowing them to swell and form a macromolecular-confined three-dimensional network structure, and then mixing silane-modified hydrophobic nanoparticles with this mixture, a dry-type hydrophobic coating is obtained. This allows the silane-modified hydrophobic nanoparticles to be embedded in the pores of the resin-formed three-dimensional network structure, thereby enhancing the adhesion between the nanoparticles and the resin, and ultimately improving the overall strength of the coating. Utilizing a molecular interpenetration mechanism, the coating's anti-aging properties are improved, enhancing both its strength and durability.

[0062] In conjunction with the second aspect, in some embodiments provided in this application, the swelling time in the mixture in which the resin and solvent are mixed and swollen to form a three-dimensional network structure is 20 to 30 hours.

[0063] Within this range of swelling time and rate, the resin and solvent can be mixed and swollen to form a mixture with a macromolecular confined three-dimensional network structure, which is beneficial for the dispersion and bonding of silane-modified hydrophobic nanoparticles and can improve the strength and durability of the coating.

[0064] In conjunction with the second aspect, in some embodiments provided in this application, the preparation method of the silane-modified hydrophobic nanoparticles includes the following steps:

[0065] Hydrophobic nanoparticles were activated and then mixed with a solvent to obtain a suspension.

[0066] The suspension was mixed with the catalyst and silane modifier, centrifuged, and the solid phase was collected to obtain silane-modified hydrophobic nanoparticles.

[0067] By activating hydrophobic nanoparticles and then modifying them with silane modifiers under a catalyst, silane groups can be grafted onto the surface of the hydrophobic nanoparticles. These groups can then combine with the silanes in the coating, improving the bonding strength between the hydrophobic nanoparticles and the resin. This allows some of the hydrophobic nanoparticles to be fixed inside the coating to enhance durability, while others are exposed in the coating to improve hydrophobic properties.

[0068] Thirdly, this application proposes a steel bridge with a hydrophobic coating on its surface, the hydrophobic coating being applied by the self-drying hydrophobic coating described in the first aspect.

[0069] The substrates to be coated include, but are not limited to, metal surfaces and concrete surfaces. After cleaning the substrate with acetone or ethanol and drying it, the self-drying hydrophobic coating can be applied to the substrate surface by brushing, dripping, rolling, spraying, or other methods. Once the solvent has completely evaporated, a white coating will appear on the surface, thus obtaining the hydrophobic coating.

[0070] In conjunction with the third aspect, in some embodiments provided in this application, the thickness of the coating is 20μm to 200μm. The thickness of the coating within this range can improve the adhesion between the coating and the bridge, and provide the bridge with better corrosion resistance.

[0071] In conjunction with the third aspect, in some embodiments provided in this application, at least a portion of the silane-modified hydrophobic nanoparticles in the coating are exposed within the resin-formed mesh coating. This exposure of at least a portion of the silane-modified hydrophobic nanoparticles within the resin-formed mesh coating ensures the hydrophobic properties of the coating and improves the service life of the bridge.

[0072] The technical solutions provided in this application will be described in detail below with reference to the embodiments.

[0073] Example 1

[0074] Example 1 of this application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0075] 1μm mica particles and 20nm silica were ground and mixed in a ball mill for 10 min, then mixed at a mass ratio of 1:1.5 and dispersed in a 5% mass concentration dilute hydrochloric acid solution to activate the particles for 20 min.

[0076] Filter and wash until the particles are neutral, then dry in a vacuum drying oven at 60°C for 24 hours;

[0077] After drying, weigh the activated filler particles, disperse them in a 0.02 g / mL ethanol solution, and stir magnetically.

[0078] Add 0.001 g / mL of tetraethyl orthosilicate to the solution;

[0079] Add sodium methylsilicate, a catalyst, to the solution at a concentration of 0.02 g / mL;

[0080] The silane modifier dodecyltrichlorosilane was added to the solution at a concentration of 0.05 mol / L.

[0081] The solution was stirred at room temperature for 6 hours, and the particles were washed by filtration / centrifugation until they were neutral. Then, they were dried in a vacuum drying oven at 60°C for 24 hours to obtain silane-modified hydrophobic nanoparticles.

[0082] Thermoplastic polyurethane resin and chlorinated ether resin were swollen in dimethylformamide solvent at a mass ratio of 8:3 for 24 hours with stirring speed of 1500 rpm. A clear solution was obtained with a resin to solvent mass ratio of 1:2.

[0083] Silane-modified hydrophobic nanoparticles were added to a clear solution, wherein the mass ratio of resin to silane-modified hydrophobic nanoparticles was 1:1.5.

[0084] Adding silane coupling agent KH570 at a concentration of 1.5% of the combined mass of the resin and particles yields a self-drying hydrophobic coating.

[0085] Example 2

[0086] Example 2 of this application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0087] 0.5μm wollastonite particles and 10nm kaolin were ground and mixed in a ball mill for 5 min, then mixed at a mass ratio of 1:4 and dispersed in a 5% mass concentration dilute hydrochloric acid solution to activate the particles for 5 min.

[0088] Filter and wash until the particles are neutral, then dry in a vacuum drying oven at 60°C for 24 hours;

[0089] After drying, weigh the activated filler particles, disperse them in a 0.02 g / mL ethanol solution, and stir magnetically.

[0090] Add tetrabutyl titanate to the solution at a concentration of 0.005 g / mL;

[0091] Potassium methylsilicate, a catalyst, was added to the solution at a concentration of 0.05 g / mL.

[0092] The silane modifier dodecyltrichlorosilane was added to the solution at a concentration of 0.01 mol / L.

[0093] The solution was stirred at room temperature for 6 hours, and the particles were washed by filtration / centrifugation until they were neutral. Then, they were dried in a vacuum drying oven at 60°C for 24 hours to obtain silane-modified hydrophobic nanoparticles.

[0094] The resin aldehyde ketone resin and perchlorate were swollen in xylene solvent at a mass ratio of 5:1 for 20 hours with a stirring speed of 1000 rpm and a resin to solvent mass ratio of 1:1.5 to obtain a clear solution.

[0095] Silane-modified hydrophobic nanoparticles were added to a clear solution, wherein the mass ratio of resin to silane-modified hydrophobic nanoparticles was 1:2.

[0096] Adding silane coupling agent KH570 at a rate of 1.0% of the total mass of the resin and particles yields a dry-type hydrophobic coating.

[0097] Example 3

[0098] Example 3 of this application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0099] 5μm glass flake particles and 50nm silica were ground and mixed in a ball mill for 15 min, then mixed at a mass ratio of 1:2 and dispersed in a 5% mass concentration dilute hydrochloric acid solution to activate the particles for 10 min.

[0100] Filter and wash until the particles are neutral, then dry in a vacuum drying oven at 60°C for 24 hours;

[0101] After drying, weigh the activated filler particles, disperse them in a 0.02 g / mL ethanol solution, and stir magnetically.

[0102] Add 0.02 g / mL of tetraethyl orthosilicate to the solution;

[0103] Potassium fluorosilicate, a catalyst, was added to the solution at a concentration of 0.1 g / mL.

[0104] The silane modifier dodecyltrichlorosilane was added to the solution at a concentration of 0.05 mol / L.

[0105] The solution was stirred at room temperature for 6 hours, and the particles were washed by filtration / centrifugation until they were neutral. Then, they were dried in a vacuum drying oven at 60°C for 24 hours to obtain silane-modified hydrophobic nanoparticles.

[0106] Thermoplastic polyurethane resin and chloroether resin were swollen in dimethylformamide solvent at a mass ratio of 8:3 for 30 hours with a stirring speed of 2000 rpm and a resin to solvent mass ratio of 1:2.5 to obtain a clear solution.

[0107] Silane-modified hydrophobic nanoparticles were added to a clear solution, wherein the mass ratio of resin to silane-modified hydrophobic nanoparticles was 1:4.

[0108] Adding silane coupling agent KH570 at a rate of 2.0% of the total mass of the resin and particles yields a self-drying hydrophobic coating.

[0109] Comparative Example 1

[0110] Comparative Example 1 of this application provides a method for preparing a self-drying hydrophobic coating, which is similar to Example 1, except that the hydrophobic nanoparticles are not modified with silane.

[0111] Comparative Example 1, since no modification was performed, had a hydrophilic coating surface.

[0112] Comparative Example 2

[0113] Comparative Example 2 of this application provides a method for preparing a self-drying hydrophobic coating, which is similar to Example 1, except that the resin is not swollen and does not form a network structure.

[0114] In Comparative Example 2, the resin did not swell, so it could not form a network structure and therefore could not form a film, resulting in cracking and peeling after coating.

[0115] Performance testing

[0116] The self-drying hydrophobic coatings prepared according to the methods of Examples 1 to 3 and Comparative Examples 1 to 2 were coated on substrates of the same material in the laboratory, with a coating thickness of 100 μm. The contact angle and roll-off angle of the coated surfaces were tested. The contact angle and roll-off angle were tested after rubbing the surface with 1000-grit sandpaper for 140 cycles under 150g pressure, and after an artificial aging test for 1000 hours. The specific test methods and steps are as follows:

[0117] 1. Hydrophobicity testing shall be performed in accordance with GB / T 30447-2013 Method for measuring contact angle of nanofilms;

[0118] 2. The wear resistance test method is to rub the surface of 1000-grit sandpaper at a constant speed under a pressure of 150g. After a certain number of times, the contact angle and roll-off angle of the surface are tested.

[0119] 3. The artificial aging test shall be conducted in accordance with GB / T 16259-2008 Test Method for Accelerated Aging of Building Materials under Artificial Climate.

[0120] The experimental results are shown in Tables 1, 2 and 3.

[0121] Table 1. Initial performance test results of self-drying hydrophobic coatings in Examples 1 to 3 and Comparative Examples 1 to 2.

[0122] Appearance Surface contact angle Roll angle Example 1 White exterior 155.1° 6.3° Example 2 White exterior 156.1° 4.3° Example 3 White exterior 158.2° 5.1° Comparative Example 1 White exterior ≤80° ≥90°

[0123] Table 2. Performance test results of self-drying hydrophobic coatings from Examples 1 to 3 and Comparative Examples 1 to 2 after 140 cycles of friction.

[0124] Appearance Surface contact angle Roll angle Example 1 White exterior 151.7° 10.6° Example 2 White exterior 154.6° 8.3° Example 3 White exterior 155.8° 5.6° Comparative Example 1 White exterior ≤80° ≥90°

[0125] Table 3. Performance test results of self-drying hydrophobic coatings in Examples 1 to 3 and Comparative Examples 1 to 2 after 1000 hours of aging.

[0126]

[0127]

[0128] SEM image of silane-modified hydrophobic nanoparticles in the self-drying hydrophobic coating of Example 1 is shown below. Figure 1 As shown, due to the coupling and silane modifier, micro-nano structures are formed on the particle surface. The resin acts as the main polymer skeleton in the coating system, which can firmly bond the silane-modified hydrophobic nanoparticles to the substrate surface.

[0129] SEM image of the self-drying hydrophobic coating of Example 1 is shown below. Figure 2 As shown, silane-modified hydrophobic nanoparticles are fully bonded together by the resin.

[0130] Optical images of the surface of the self-drying hydrophobic coating in Example 1 are shown below. Figure 3 As shown.

[0131] The side view of the contact angle and roll-off angle of the self-drying hydrophobic coating surface in Example 1 is shown below. Figure 4 As shown.

[0132] A schematic diagram of the wear test of the self-drying hydrophobic coating in Example 1 is shown below. Figure 5 As shown.

[0133] The change in contact angle with the number of wear cycles in the wear test of the self-drying hydrophobic coating in Example 1 is as follows: Figure 6 As shown, the number of abrasion cycles is related to the adhesion force. The more abrasion cycles a nanoparticles withstand, the tighter the bond between them and the resin, and the less likely they are to delaminate or detach.

[0134] The cross-cut test results of the self-drying hydrophobic coating in Example 1 are shown in the figure below. Figure 7 As shown.

[0135] The comparison diagram of the self-drying hydrophobic coating of Example 1 in its initial state, after 500 hours of aging, and after 1000 hours of aging is shown below. Figure 8 As shown.

[0136] The side view of the contact angle and roll-off angle of the self-drying hydrophobic coating of Comparative Example 1 after aging for 1000 hours is shown below. Figure 9 As shown, the aging resistance time is related to the resin strength. The longer the aging resistance time, the higher the resin strength. The aging resistance of the resin can be improved by increasing the interpenetration between silane-modified hydrophobic nanoparticles and the resin.

[0137] The accumulation of corrosive media on the surface of bridge steel structures leads to corrosion. This application aims to ensure the safety of bridges in high-humidity and corrosive environments. Addressing issues such as low strength, poor resistance, and long construction time of superhydrophobic coatings, it proposes a self-drying hydrophobic coating for bridge steel structures. This coating can be directly applied to the outer layer of existing bridge coatings. Through a high-strength resin interpenetration design and multi-scale particle compounding, the strength and resistance of the superhydrophobic outer layer are improved. The high-strength resin can fully swell in the coating solvent, allowing the coating to cure immediately after solvent evaporation, eliminating the need for additional curing time and reducing the impact of the external environment on coating construction. The prepared coating achieves a contact angle ≥150°, a roll-off angle ≤5°, and can withstand 1000 hours of artificial aging and salt spray testing. Even after 150 polishing cycles with 1000-grit sandpaper, it still retains its superhydrophobic properties of a contact angle ≥150° and a roll-off angle ≤6°.

[0138] In summary, by selecting a non-reactive, high-hardness, high-adhesion resin, the resin can fully swell in the solvent, encapsulating silane-modified hydrophobic nanoparticles. After coating the substrate surface, it rapidly solidifies into a film as the solvent evaporates, forming a superhydrophobic coating without requiring additional curing time. The use of silane-modified hydrophobic nanoparticles enhances the coating strength and improves the adhesion between the resin matrix and the nanoparticles. This allows the hydrophobic nanoparticles to easily adhere and embed within the macromolecular network structure, thereby strengthening the adhesion between the nanoparticles and the resin matrix, ultimately improving the overall strength of the coating and extending its service life.

[0139] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0140] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0141] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. 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 present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A self-drying hydrophobic coating, characterized in that, Its raw materials include resin, silane-modified hydrophobic nanoparticles, and solvents, wherein: At least a portion of the silane-modified hydrophobic nanoparticles are embedded within the pores of the resin-formed mesh structure. The resin includes at least one of thermoplastic polyurethane, aldehyde-ketone resin, terpene resin and polyvinyl chloride; The silane-modified hydrophobic nanoparticles include at least one of silica, mica, wollastonite, kaolin, and glass flakes. The silane modifier of the silane-modified hydrophobic nanoparticles includes at least one of perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane, and perfluorododecyltrichlorosilane. The silane-modified hydrophobic nanoparticles include silane-modified hydrophobic nanoparticles with a first particle size and silane-modified hydrophobic nanoparticles with a second particle size. The first particle size is 0.5~5μm, and the second particle size is 10~50nm. The mass ratio of the silane-modified hydrophobic nanoparticles with the first particle size to the silane-modified hydrophobic nanoparticles with the second particle size is 1:(1.5~4). During preparation, the resin and solvent are mixed and swollen to form a three-dimensional network structure; silane-modified hydrophobic nanoparticles are mixed with the mixture to obtain a dry hydrophobic coating.

2. The self-drying hydrophobic coating as described in claim 1, characterized in that, The resin also includes at least one of chlorinated ether resin, perchlorinated vinyl, acrylic resin, and chlorinated vinyl acetate.

3. The self-drying hydrophobic coating as described in claim 1, characterized in that, The mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:(1.5~2).

4. A method for preparing a self-drying hydrophobic coating as described in any one of claims 1 to 3, characterized in that, Includes the following steps: The resin and solvent are mixed and swollen to form a three-dimensional network structure. A self-drying hydrophobic coating is obtained by mixing silane-modified hydrophobic nanoparticles with a mixture.

5. The method for preparing the self-drying hydrophobic coating as described in claim 4, characterized in that, In the mixture in which resin and solvent are mixed and swollen to form a three-dimensional network structure: The swelling time is 20-30 hours.

6. The method for preparing the self-drying hydrophobic coating as described in claim 4, characterized in that, The preparation method of the silane-modified hydrophobic nanoparticles includes the following steps: Hydrophobic nanoparticles were activated and then mixed with a solvent to obtain a suspension. The suspension was mixed with the catalyst and silane modifier, centrifuged, and the solid phase was collected to obtain silane-modified hydrophobic nanoparticles.

7. A steel bridge, characterized in that, Its surface has a hydrophobic coating, which is formed by applying a self-drying hydrophobic coating as described in any one of claims 1 to 3.

8. The steel bridge as described in claim 7, characterized in that: The coating thickness is 20μm~200μm; and / or, At least a portion of the silane-modified hydrophobic nanoparticles in the coating are exposed in the resin-formed mesh coating.

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