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

Abstract

The invention discloses a self-drying hydrophobic coating, a preparation method thereof and a steel bridge, and relates to the technical field of bridges. The raw materials of the silane-modified hydrophobic nano-coating comprise resin, silane-modified hydrophobic nano-particles and a solvent, wherein at least part of the silane-modified hydrophobic nano-particles are embedded in reticular structure holes formed by the resin; the resin comprises at least one of thermoplastic polyurethane, aldehyde ketone resin, terpene resin and polyvinyl chloride; the silane modified hydrophobic nanoparticles comprise at least one of silicon dioxide, mica, wollastonite, kaolin and glass flakes. Non-reactive high-hardness and high-bonding resin is selected, the resin can fully swell in a solvent and coat silane modified hydrophobic nanoparticles, after the surface of a substrate is coated with the resin, the resin is rapidly cured to form a film along with volatilization of the solvent, the super-hydrophobic coating can be formed, extra curing reaction time is not needed, the strength of the coating is improved by adopting the silane modified hydrophobic nanoparticles, and therefore the super-hydrophobic coating is formed. And the bonding problem of the resin matrix and the nanoparticles is improved.

Description

Technical Field

[0001] The present application relates to the technical field of bridges, and in particular to a self-drying hydrophobic coating, a preparation method thereof, and a steel bridge. Background Art

[0002] As an important transportation infrastructure, bridges play a vital role in regional economic development and people's lives. However, in special environments such as oceans and plateaus, bridge steel structures face severe corrosion challenges. The marine environment is rich in salt and water, and plateaus may have strong ultraviolet radiation, large temperature differences and other unfavorable factors, all of which accelerate the corrosion process of bridge steel structures. Traditional bridge steel structure protection measures often have certain limitations and cannot provide long-term and effective protection. Summary of the invention

[0003] The present application provides a self-drying hydrophobic coating and a preparation method thereof and a steel bridge to solve the problem that existing protective measures often have certain limitations and cannot provide long-term and effective protection.

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

[0005] At least part of the silane-modified hydrophobic nanoparticles are embedded in the pores of the network structure formed by the resin;

[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 silicon dioxide, mica, wollastonite, kaolin and glass flakes.

[0008] The present application selects a non-reactive high-hardness, high-adhesion resin, and the resin can be fully swollen in the solvent, coating the silane-modified hydrophobic nanoparticles. After coating the surface of the substrate, as the solvent evaporates, it quickly solidifies into a film to form a super-hydrophobic coating. No additional curing reaction time is required. Silane-modified hydrophobic nanoparticles are used to improve the strength of the coating and improve the adhesion problem between the resin matrix and the nanoparticles. The hydrophobic nanoparticles can be easily bonded and embedded in the macromolecular network structure, thereby enhancing the adhesion between the nanoparticles and the resin matrix, thereby improving the overall strength of the coating and increasing its service life.

[0009] It should be noted that in order to further improve the bonding strength between the silane-modified hydrophobic nanoparticles and the resin, a long-chain silane coupling agent can also be added to the coating so that the silane-modified hydrophobic nanoparticles are more firmly fixed to the coating, reducing the stratification of the coating and increasing 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 to 5 μm; and / or,

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

[0013] 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).

[0014] The use of silane-modified hydrophobic nanoparticles of different particle sizes can improve the strength of the coating, improve the bonding force between the hydrophobic nanoparticles and the resin, and thus improve the hydrophobic performance of the coating. 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 within this range, so that a part of the silane-modified hydrophobic nanoparticles can be coated inside the three-dimensional network structure formed by the resin, and the other part can be exposed outside the three-dimensional network structure formed by the resin, thereby improving the hydrophobic performance.

[0015] In some embodiments, the silane modifier of the silane-modified hydrophobic nanoparticles includes at least one of perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane and perfluorododecyltrichlorosilane. The use of the above silane modifier can improve the dispersibility of the hydrophobic nanoparticles in the resin, improve the uniformity, and improve the bonding force between the hydrophobic nanoparticles and the resin.

[0016] In some embodiments, the resin further comprises at least one of chloroether resin, perchloroethylene, acrylic resin and chlorinated ethylene-vinyl acetate. Adding at least one of the above resins can improve the anti-aging performance and salt spray resistance of the coating.

[0017] In some embodiments, the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:(1.5-2). When the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is within this range, the mass proportion of the silane-modified hydrophobic nanoparticles in the coating can be improved, the adhesion problem between the resin and the nanoparticles can be improved, and the problem of the failure of the surface super-hydrophobic property due to the complete coating of the nanoparticles by the resin due to excessive resin can be reduced.

[0018] In a second aspect, the present application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0019] The resin is mixed with a solvent, and swelled to form a mixed liquid having a three-dimensional network structure;

[0020] The silane-modified hydrophobic nanoparticles are mixed with the mixed liquid to obtain a dry hydrophobic coating.

[0021] By mixing the resin and the solvent, swelling them, and forming a mixed solution with a three-dimensional network structure of macromolecule confinement, and then mixing the silane-modified hydrophobic nanoparticles with the mixed solution, a self-drying hydrophobic coating is obtained, which can embed the silane-modified hydrophobic nanoparticles in the pores of the three-dimensional network structure formed by the resin, thereby enhancing the adhesion between the nanoparticles and the resin, and then improving the overall strength of the coating. The molecular interpenetration method is used to improve the anti-aging performance of the coating, and the coating's tolerance performance is enhanced while improving the strength of the coating.

[0022] In some embodiments, the resin and the solvent are mixed and swelled to form a mixed solution with a three-dimensional network structure:

[0023] The swelling time is 20 to 30 hours. When the swelling time and rate are within this range, the resin and the solvent can be mixed and swelled to form a mixed liquid with a three-dimensional network structure of macromolecule confinement, which is beneficial to the dispersion and combination of silane-modified hydrophobic nanoparticles and can improve the strength and durability of the coating.

[0024] In some embodiments, the method for preparing the silane-modified hydrophobic nanoparticles comprises the following steps:

[0025] Activating the hydrophobic nanoparticles and mixing them with a solvent to obtain a suspension;

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

[0027] By activating the hydrophobic nanoparticles and then modifying them with a silane modifier under a catalyst, silane groups can be grafted onto the surface of the hydrophobic nanoparticles, combining with the silane in the coating to improve the strength of the bond between the hydrophobic nanoparticles and the resin. This allows a portion of the hydrophobic nanoparticles to be fixed inside the coating to improve durability, while the other portion is exposed in the coating to improve the hydrophobic properties.

[0028] In a third aspect, the present application proposes a steel bridge having a hydrophobic coating on its surface, wherein the hydrophobic coating is coated with the self-drying hydrophobic coating described in the first aspect.

[0029] In some embodiments, the thickness of the coating is 20 μm to 200 μm. 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; and / or,

[0030] In the coating, at least part of the silane-modified hydrophobic nanoparticles are exposed to the network coating formed by the resin. At least part of the silane-modified hydrophobic nanoparticles are exposed to the network coating formed by the resin, which can ensure the hydrophobic performance of the coating and improve the service life of the bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

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

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

[0035] Figure 4 This is a side view of the contact angle and rolling angle of the self-drying hydrophobic coating surface of Example 1 of the present application.

[0036] Figure 5 Schematic diagram of the wear experiment of the self-drying hydrophobic coating in Example 1 of the present application.

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

[0038] Figure 7 This is a cross-cutting test effect diagram of the self-drying hydrophobic coating of Example 1 of the present application.

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

[0040] Fig. 9 This is a side view of the contact angle and rolling angle of the coating surface of the self-drying hydrophobic coating of comparative example 1 of the present application after aging for 1000 hours. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0042] As an important transportation infrastructure, bridges play a vital role in regional economic development and people's lives. However, in special environments such as oceans and plateaus, bridge steel structures face severe corrosion challenges. The marine environment is rich in salt and water, and plateau areas may have unfavorable factors such as strong ultraviolet radiation and large temperature differences, which accelerate the corrosion process of bridge steel structures. Traditional bridge steel structure protection measures often have certain limitations and cannot provide long-term and effective protection. Developing an efficient and reliable bridge steel structure protection method has become a top priority.

[0043] The application of super-hydrophobic coatings is subject to the strength and tolerance of the surface, and it is difficult to meet long-term industrial applications. In the fields of aerospace, energy, construction, etc., the surface is in a harsh working environment for a long time, such as dust, rain and snow, ultraviolet radiation, etc., which will cause serious wear on the surface, thereby making the surface function ineffective, having a negative impact on the normal operation of the equipment, and even threatening the safety of equipment operation. Laser ablation is used to construct micro-nano structures on the surface of rigid substrates such as metals, or to construct rigid structures and fill hydrophobic nanoparticles inside to improve the surface strength. However, this method is complex and difficult to apply on a large scale. Reinforced structures such as glass fiber cloth, carbon fiber mesh, etc. are pre-laid on the surface of the substrate, and then sprayed / brushed with hydrophobic coatings to achieve the improvement of the strength of the hydrophobic outer layer. However, the reinforcement structure is complicated to lay on the surface of complex-shaped components, and in order to make the reinforcement structure bonded to the substrate surface intact, the prepared coating thickness is relatively thick. A resin layer is constructed on the substrate, and hydrophobic nanoparticles are laid on the surface when the coating is semi-cured. First, prepare hydrophobic nanoparticles, then blend with resin to form a coating, add a curing agent, and then use spraying / brushing to prepare a super-hydrophobic surface on the surface. Both methods can significantly extend the service life of the super-hydrophobic surface and ensure lasting protection of the substrate. However, in the preparation process, the synthesis of hydrophobic nanoparticles and the preparation of the coating need to be divided into multiple steps. In addition, in the preparation strategy of hydrophobic particles & resin mixing, the resin curing often takes a long time and even requires heating treatment. In this process, the coating is extremely fragile and is easily affected by rain, moisture, etc., resulting in poor curing effect, affecting the performance and durability of the coating. With the increase in bridge operation and maintenance and waterproof and anti-fouling needs, how to provide low-cost, efficient and durable liquid medium isolation means for bridge structures, and provide effective medium isolation guarantees for bridge structures to cope with extreme climate environments such as wind, rain, snow and ice has become the key to research.

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

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

[0046] At least part of the silane-modified hydrophobic nanoparticles are embedded in the pores of the network structure formed by the resin;

[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 silicon dioxide, mica, wollastonite, kaolin and glass flakes.

[0049] The present application selects a non-reactive high-hardness, high-adhesion resin, and the resin can be fully swollen in the solvent, coating the silane-modified hydrophobic nanoparticles. After coating the surface of the substrate, as the solvent evaporates, it quickly solidifies into a film to form a super-hydrophobic coating. No additional curing reaction time is required. Silane-modified hydrophobic nanoparticles are used to improve the strength of the coating and improve the adhesion problem between the resin matrix and the nanoparticles. The hydrophobic nanoparticles can be easily bonded and embedded in the macromolecular network structure, thereby enhancing the adhesion between the nanoparticles and the resin matrix, thereby improving the overall strength of the coating and increasing its service life.

[0050] It should be noted that in order to further improve the bonding strength between the silane-modified hydrophobic nanoparticles and the resin, a long-chain silane coupling agent can also be added to the coating so that the silane-modified hydrophobic nanoparticles are more firmly fixed to the coating, reducing the stratification of the coating and increasing the service life of the coating.

[0051] In combination with the first aspect, in some embodiments provided in the present 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 first particle size is 0.5 to 5 μm.

[0052] In combination with the first aspect, in some embodiments provided in the present 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 second particle size is 10 to 50 nm.

[0053] In combination with the first aspect, in some embodiments provided in the present 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] The use of silane-modified hydrophobic nanoparticles of different particle sizes can improve the strength of the coating, improve the bonding force between the hydrophobic nanoparticles and the resin, and thus improve the hydrophobic performance of the coating. 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 within this range, so that a part of the silane-modified hydrophobic nanoparticles can be coated inside the three-dimensional network structure formed by the resin, and the other part can be exposed outside the three-dimensional network structure formed by the resin, thereby improving the hydrophobic performance.

[0055] In combination with the first aspect, in some embodiments provided in the present application, the silane modifier of the silane-modified hydrophobic nanoparticles includes at least one of perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane and perfluorododecyltrichlorosilane. The use of the above silane modifier can improve the dispersibility of the hydrophobic nanoparticles in the resin, improve the uniformity, and improve the bonding force between the hydrophobic nanoparticles and the resin.

[0056] In combination with the first aspect, in some embodiments provided in the present application, the resin further comprises at least one of chloroether resin, perchloroethylene, acrylic resin and chlorinated ethylene-vinyl acetate. Adding at least one of the above resins can improve the anti-aging performance and salt spray resistance of the coating.

[0057] In combination with the first aspect, in some embodiments provided in the present application, the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:(1.5-2). When the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is within this range, the mass proportion of the silane-modified hydrophobic nanoparticles in the coating can be improved, the adhesion problem between the resin and the nanoparticles can be improved, and the problem of the failure of the surface super-hydrophobic property due to the complete coating of the nanoparticles by the resin due to excessive resin can be reduced.

[0058] In a second aspect, the present application provides a method for preparing a self-drying hydrophobic coating, comprising the following steps:

[0059] The resin is mixed with a solvent, and swelled to form a mixed liquid having a three-dimensional network structure;

[0060] The silane-modified hydrophobic nanoparticles are mixed with the mixed liquid to obtain a dry hydrophobic coating.

[0061] By mixing the resin and the solvent, swelling them, and forming a mixed solution with a three-dimensional network structure of macromolecule confinement, and then mixing the silane-modified hydrophobic nanoparticles with the mixed solution, a self-drying hydrophobic coating is obtained, which can embed the silane-modified hydrophobic nanoparticles in the pores of the three-dimensional network structure formed by the resin, thereby enhancing the adhesion between the nanoparticles and the resin, and then improving the overall strength of the coating. The molecular interpenetration method is used to improve the anti-aging performance of the coating, and the coating's tolerance performance is enhanced while improving the strength of the coating.

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

[0063] When the swelling time and rate are within this range, the resin and the solvent can be mixed and swelled to form a mixed liquid with a three-dimensional network structure with macromolecular confinement, which is beneficial to the dispersion and combination 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 the present application, the method for preparing the silane-modified hydrophobic nanoparticles comprises the following steps:

[0065] Activating the hydrophobic nanoparticles and mixing them with a solvent to obtain a suspension;

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

[0067] By activating the hydrophobic nanoparticles and then modifying them with a silane modifier under a catalyst, silane groups can be grafted onto the surface of the hydrophobic nanoparticles, combining with the silane in the coating to improve the strength of the bond between the hydrophobic nanoparticles and the resin. This allows a portion of the hydrophobic nanoparticles to be fixed inside the coating to improve durability, while the other portion is exposed in the coating to improve the hydrophobic properties.

[0068] In a third aspect, the present application proposes a steel bridge having a hydrophobic coating on its surface, wherein the hydrophobic coating is coated with the self-drying hydrophobic coating described in the first aspect.

[0069] The coated substrate includes but is not limited to metal surfaces and concrete surfaces. The substrate is cleaned with acetone and ethanol and then dried. The self-drying hydrophobic coating can be processed on the surface of the substrate by brushing, dripping, rolling, spraying, etc. After the solvent is completely evaporated, a white coating appears on the surface, and the hydrophobic coating is obtained.

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

[0071] In conjunction with the third aspect, in some embodiments provided in the present application, at least a portion of the silane-modified hydrophobic nanoparticles in the coating are exposed to a mesh coating formed by the resin. At least a portion of the silane-modified hydrophobic nanoparticles exposed to a mesh coating formed by the resin can ensure the hydrophobic performance of the coating and improve the service life of the bridge.

[0072] The technical solution provided in this application is described in detail below in conjunction with embodiments.

[0073] Example 1

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

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

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

[0077] After drying, the activated filler particles were weighed, dispersed in a 0.02 g / mL ethanol solution, and magnetically stirred;

[0078] Add ethyl orthosilicate to the solution in an amount of 0.001 g / mL;

[0079] Add the catalyst sodium methyl silicate to the solution in an amount of 0.02 g / mL;

[0080] Add silane modifier dodecyltrichlorosilane to the solution in an amount of 0.05 mol / L;

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

[0082] The resin thermoplastic polyurethane and the chloroether resin were swollen in the solvent dimethylformamide at a mass ratio of 8:3 for 24 hours, with a stirring speed of 1500 rpm and a mass ratio of the resin to the solvent of 1:2 to obtain a clear solution;

[0083] adding silane-modified hydrophobic nanoparticles to the clear solution, wherein the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:1.5;

[0084] Silane coupling agent KH570 was added, and the addition amount of silane coupling agent KH570 was 1.5% of the total mass of the resin and the particles, and was obtained from the dry hydrophobic coating.

[0085] Example 2

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

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

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

[0089] After drying, the activated filler particles were weighed, dispersed in a 0.02 g / mL ethanol solution, and magnetically stirred;

[0090] Tetrabutyl titanate was added to the solution in an amount of 0.005 g / mL;

[0091] Add the catalyst potassium methyl silicate to the solution in an amount of 0.05 g / mL;

[0092] Add silane modifier dodecyltrichlorosilane to the solution in an amount of 0.01 mol / L;

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

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

[0095] adding silane-modified hydrophobic nanoparticles to the clear solution, wherein the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:2;

[0096] Silane coupling agent KH570 was added, and the addition amount of silane coupling agent KH570 was 1.0% of the total mass of resin and particles, obtained from the dry hydrophobic coating.

[0097] Example 3

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

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

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

[0101] After drying, the activated filler particles were weighed, dispersed in a 0.02 g / mL ethanol solution, and magnetically stirred;

[0102] Add ethyl orthosilicate to the solution in an amount of 0.02 g / mL;

[0103] Add the catalyst potassium fluorosilicate to the solution in an amount of 0.1 g / mL;

[0104] Add silane modifier dodecyltrichlorosilane to the solution in an amount of 0.05 mol / L;

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

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

[0107] Adding silane-modified hydrophobic nanoparticles to the clear solution, wherein the mass ratio of the resin to the silane-modified hydrophobic nanoparticles is 1:4;

[0108] Silane coupling agent KH570 was added, and the addition amount of silane coupling agent KH570 was 2.0% of the total mass of the resin and the particles, and was obtained from the dry hydrophobic coating.

[0109] Comparative Example 1

[0110] Comparative Example 1 of the present 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] Since the comparative example 1 was not modified, the coating surface was a hydrophilic surface.

[0112] Comparative Example 2

[0113] Comparative Example 2 of the present 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 a network structure is not formed.

[0114] In Comparative Example 2, the resin did not swell, so a network structure could not be formed and a film could not be formed. The coating cracked and fell off after coating.

[0115] Performance Testing

[0116] The self-drying hydrophobic coatings of the preparation methods of the self-drying hydrophobic coatings 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, and the contact angle and rolling angle tests were performed on the coated coatings. The contact angle and rolling angle tests were performed after rubbing the surface of 1000-mesh sandpaper 140 times under a pressure of 150 g, and the contact angle and rolling angle tests were performed after an artificial aging test for 1000 h. The specific test method steps are as follows:

[0117] 1. The hydrophobic test refers to GB / T 30447-2013 nano film contact angle measurement method;

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

[0119] 3. The artificial aging test shall refer to GB / T 16259-2008 Test method for accelerated aging of building materials under artificial climate.

[0120] The test results are shown in Table 1, Table 2 and Table 3.

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

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

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

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

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

[0126]

[0127]

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

[0129] The SEM image of the self-drying hydrophobic coating of Example 1 is as follows: Figure 2 As shown, the silane-modified hydrophobic nanoparticles were well bound by the resin.

[0130] The optical image of the self-drying hydrophobic coating surface of Example 1 is as follows Figure 3 shown.

[0131] The side view of the contact angle and rolling angle of the self-drying hydrophobic coating surface of Example 1 is as follows Figure 4 shown.

[0132] The schematic diagram of the wear test of the self-drying hydrophobic coating in Example 1 is as follows Figure 5 shown.

[0133] The change of contact angle with the number of wear times in the wear test of the self-drying hydrophobic coating of Example 1 is as follows: Figure 6 The number of wear times is related to the bonding force. The more wear times, the tighter the bond between the nanoparticles and the resin, and the less likely they are to fall off.

[0134] The cross-cutting test effect diagram of the self-drying hydrophobic coating of Example 1 is as follows Figure 7 shown.

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

[0136] The contact angle and rolling angle of the coating surface of the self-drying hydrophobic coating of comparative example 1 after aging for 1000 hours are shown in the side view. Fig. 9 The aging resistance time is related to the resin strength. The longer the aging resistance time is, the higher the resin strength is. The aging resistance of the resin can be improved by increasing the interpenetrating structure of silane-modified hydrophobic nanoparticles and the resin.

[0137] The enrichment of corrosive media on the surface of bridge steel structure will lead to corrosion of bridge steel structure. This application aims at the safety measures of bridges in high humidity and corrosive environment. For a series of problems such as low strength, poor tolerance and long construction time of super hydrophobic coating, a self-drying hydrophobic coating for bridge steel structure is proposed, which can be directly constructed on the outer layer of existing bridge coating. The strength and tolerance of super hydrophobic outer layer are improved by high-strength resin interpenetration design and multi-scale particle compounding. High-strength resin can be fully swollen in coating solvent, so that the coating can be cured after the solvent evaporates, without additional curing reaction time, reducing the impact of external environment on coating construction. The prepared coating can achieve contact angle ≥150°, rolling angle ≤5°, and can withstand 1000h of artificial aging and salt spray test, and can still have contact angle ≥150° and rolling angle ≤6° after 1000 mesh sandpaper polishing 150 times.

[0138] In summary, by selecting a non-reactive high-hardness, high-adhesive resin, the resin can be fully swollen in the solvent, coating the silane-modified hydrophobic nanoparticles, and after coating the substrate surface, as the solvent evaporates, it quickly solidifies into a film to form a super-hydrophobic coating. No additional curing reaction time is required. The use of silane-modified hydrophobic nanoparticles can improve the strength of the coating and improve the adhesion problem between the resin matrix and the nanoparticles. The hydrophobic nanoparticles can be easily bonded and embedded in the macromolecular network structure, thereby enhancing the adhesion between the nanoparticles and the resin matrix, thereby improving the overall strength of the coating and increasing its service life.

[0139] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0140] It should be noted that, in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically stipulated.

[0141] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A self-drying hydrophobic coating, characterized in that: The raw materials include resin and silane-modified hydrophobic nanoparticles and solvent, wherein: At least part of the silane-modified hydrophobic nanoparticles are embedded in the pores of the 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 silicon dioxide, mica, wollastonite, kaolin and glass flakes.

2. The self-drying hydrophobic coating according to claim 1, characterized in that: 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 first particle size is 0.5 to 5 μm; and / or, The second particle size is 10 to 50 nm; and / or, 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).

3. The self-drying hydrophobic coating according to claim 1, characterized in that The silane modifier of the silane-modified hydrophobic nanoparticles includes at least one of perfluorooctyltriethoxysilane, octadecyltrichlorosilane, dodecyltrichlorosilane and perfluorododecyltrichlorosilane.

4. The self-drying hydrophobic coating according to claim 1, characterized in that The resin also includes at least one of chloroether resin, perchloroethylene, acrylic resin and chlorinated ethylene-vinyl acetate.

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

6. A method for preparing a self-drying hydrophobic coating as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: The resin is mixed with a solvent, and swelled to form a mixed liquid having a three-dimensional network structure; The silane-modified hydrophobic nanoparticles are mixed with the mixed liquid to obtain a dry hydrophobic coating.

7. The method for preparing a self-drying hydrophobic coating according to claim 6, wherein The resin and the solvent are mixed and swelled to form a mixed solution with a three-dimensional network structure: The swelling time is 20 to 30 hours.

8. The method for preparing a self-drying hydrophobic coating as claimed in claim 6, wherein The preparation method of the silane-modified hydrophobic nanoparticles comprises the following steps: Activating the hydrophobic nanoparticles and mixing them with a solvent to obtain a suspension; The suspension is mixed with the catalyst and the silane modifier, centrifuged, and the solid phase is taken to obtain the silane-modified hydrophobic nanoparticles.

9. A steel bridge, characterized in that: The surface of the invention has a hydrophobic coating, which is formed by coating the self-drying hydrophobic coating as described in any one of claims 1 to 5.

10. The steel bridge according to claim 9, characterized in that: The coating has a thickness of 20 μm to 200 μm; and / or, In the coating, at least a portion of the silane-modified hydrophobic nanoparticles are exposed to the network coating formed by the resin.

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