An organosilicon composite drag-reducing coating, its preparation method and application

Abstract

This invention provides an organosilicon composite drag-reducing coating, its preparation method, and its application. The preparation method includes the following steps: S1. Tetraethyl orthosilicate, alkenylsilane, catalyst, water, and a first solvent are stirred and allowed to stand to obtain a first mixture. The first mixture is then coated onto the surface of a substrate and heated to form an adhesion-promoting layer. S2. Silica particles, perfluoroalkylethylene, a UV-curing agent, and a second solvent are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is then coated onto the surface of the adhesion-promoting agent layer obtained in step S1 and cured under ultraviolet light to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion-promoting layer and a drag-reducing functional layer is obtained. The organosilicon composite drag-reducing coating prepared by this invention has good adhesion and drag-reducing performance.

Description

Technical Field

[0001] This invention belongs to the field of drag-reducing coating technology, specifically relating to an organosilicon composite drag-reducing coating, its preparation method, and its application. Background Technology

[0002] The resistance experienced by marine vessels during navigation is one of the main factors affecting their speed and energy consumption. For objects moving underwater or on the surface, the resistance mainly consists of viscous drag (frictional drag) and wave-making drag, with viscous drag accounting for a large proportion. In maritime transport, surface frictional drag accounts for 60-70% of the total resistance of cargo ships, and shipping accounts for 8.5% of global oil consumption and 3.3% of CO2 emissions. Therefore, surface frictional drag plays a crucial role in total resistance, and reducing frictional drag during navigation has a significant impact on improving shipping efficiency, saving energy, reducing greenhouse gas emissions, and reducing pollution.

[0003] When a viscous fluid (such as water) flows over a hydrophilic surface, the relative velocity between the fluid and the boundary is zero, a condition known as no-slip boundary condition. However, when the surface is hydrophobic, there is a velocity difference between the fluid and the boundary. The distance from the boundary to the point where the fluid velocity drops to zero is called the slip length, and it is generally accepted that a larger slip length produces a greater drag reduction effect. The slip of a hydrophobic surface varies depending on the measurement method used, but the results are typically small, below 100 nm. Only when a hydrophobic surface combines micron- or nanometer-level roughness, achieving a superhydrophobic state, can it possess a large slip length, thus producing a significant drag reduction effect.

[0004] Most drag-reducing coatings currently available use organic coatings, which have complex synthesis processes, poor wear resistance, and are easily damaged by physical and mechanical means. In addition, because they require hydrophobicity, the surface energy of the coating is low, resulting in weak adhesion to the substrate and easy peeling. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an organosilicon composite drag-reducing coating, its preparation method and application, wherein the organosilicon composite drag-reducing coating has good adhesion and drag-reducing performance.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for preparing an organosilicon composite drag-reducing coating includes the following steps:

[0008] S1. Tetraethyl orthosilicate, alkenylsilane, catalyst, water and first solvent are stirred and allowed to stand to obtain a first mixture. The first mixture is coated on the surface of the substrate and heated to form an adhesion promoting layer.

[0009] S2. Stir silica particles, perfluoroalkyl ethylene, light curing agent and second solvent in the dark until they are mixed evenly to obtain a second mixture. Apply the second mixture to the surface of the adhesion promoter layer obtained in step S1 and cure it with ultraviolet light to form a drag reduction functional layer. Finally, an organosilicon composite drag reduction coating composed of an adhesion promoter layer and a drag reduction functional layer is obtained.

[0010] Further, in step S1 of the present invention, by weight percentage, there are 8-12% tetraethyl orthosilicate, 12-38% alkenylsilane, 0.1-0.5% catalyst, 2-10% water, and the balance is the first solvent.

[0011] Further, in step S1 of the present invention, the alkenylsilane is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, and diallyldimethoxysilane; the catalyst is one or more of formic acid, acetic acid, and hydrochloric acid; and the first solvent is one or more of ethanol, isopropanol, and petroleum ether.

[0012] Furthermore, in step S1 of the present invention, the stirring time is 4-12 hours, the standing time is 24-72 hours, the baking temperature is 40-80°C, and the baking time is 10-30 minutes.

[0013] Furthermore, the thickness of the adhesion-promoting layer is 1-25 μm.

[0014] Furthermore, in step S2 of the present invention, by weight percentage, there are 1-4% silica particles, 5-25% perfluoroalkyl ethylene, 0.1-2% photocuring agent, and the balance is a second solvent.

[0015] Furthermore, in step S2 of the present invention, the particle size of the silica particles is 200-1000 nm, the perfluoroalkyl ethylene is one or more of perfluorooctyl ethylene, perfluorohexyl ethylene, and perfluorodecyl ethylene, the photocuring agent is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, diphenyl ethyl ketone, and α-hydroxyalkyl phenyl ketone, and the second solvent is one or more of ethanol, ethyl acetate, and petroleum ether.

[0016] Furthermore, in step S2 of the present invention, the power of ultraviolet curing is 1-3kW, and the ultraviolet curing time is 30-600s.

[0017] Furthermore, the thickness of the drag-reducing functional layer is 1-25 μm.

[0018] This invention also provides an organosilicon composite drag-reducing coating prepared by the aforementioned method.

[0019] Furthermore, the static contact angle of the organosilicon composite drag-reducing coating of the present invention is greater than 150°, and the drag reduction rate is 2-10%.

[0020] Furthermore, the present invention also provides the application of the aforementioned organosilicon composite drag-reducing coating in the field of surface and underwater vehicles.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) This invention uses an organosilicon coating as an adhesion-promoting layer. It utilizes the hydrolytic cross-linking and condensation of tetraethyl orthosilicate and alkenylsilane to form a large number of silanol groups (Si-OH), which can firmly bond with various substrates. Simultaneously, it introduces vinyl double bond active sites into the coating, laying the groundwork for the subsequent hydrophobicization of the functional coating. The drag-reducing functional layer utilizes the double bond active sites of the adhesion-promoting layer, which can be flexibly adjusted according to different functional requirements. Through UV curing, the double bonds in the alkenylsilane and perfluoroalkylethylene are cross-linked, allowing the adhesion-promoting layer and the drag-reducing functional layer to be chemically bonded, thereby improving the adhesion and drag-reducing performance of the organosilicon composite drag-reducing coating. Furthermore, UV curing has the advantages of shorter curing time, stronger inter-coating bonding, and continuous application compared to conventional coatings.

[0023] 2) Compared with the existing technology, the adhesion promotion layer and drag reduction functional layer of the present invention are prepared by the "one-pot method", which is simpler and easier to construct than conventional organic coatings. It can be applied to a large area by spraying, so it has great research significance and application prospects. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The image shows the surface SEM morphology of the organosilicon composite drag-reducing coating obtained in Example 1 of this invention.

[0026] Figure 2 This is a schematic diagram of the static contact angle of the organosilicon composite drag-reducing coating obtained in Example 1 of the present invention;

[0027] Figure 3 The ATR infrared spectrum of the organosilicon composite drag-reducing coating prepared in Example 1 of this invention;

[0028] Figure 4 This is a schematic diagram of the organosilicon composite drag-reducing coating prepared in Example 1 of the present invention applied to the surface of an aluminum alloy. Detailed Implementation

[0029] The invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as intended to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0030] Example 1: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0031] S1. Ethyl orthosilicate, vinyltrimethoxysilane, hydrochloric acid, water, and ethanol are stirred for 6 hours and then allowed to stand for 24 hours to obtain a first mixture. The first mixture is coated on the surface of the substrate and baked at 60°C for 15 minutes to form an adhesion promoting layer. By weight percentage, 9.2% is ethyl orthosilicate, 12.8% is vinyltrimethoxysilane, 0.2% is hydrochloric acid, 5.4% is water, and the balance is ethanol. The substrate is a 15cm radius turntable of a rotating disk resistance testing platform.

[0032] S2. Silica particles with a particle size of 500 nm, perfluorooctylethylene, 2-hydroxy-2-methyl-1-phenylpropanone, and ethanol are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 1kW ultraviolet light for 40s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 1%, perfluorooctylethylene is 20%, 2-hydroxy-2-methyl-1-phenylpropanone is 0.2%, and the balance is ethanol.

[0033] Example 2: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0034] S1. Ethyl tetrasilicate, allyltrimethoxysilane, hydrochloric acid, water, and ethanol are stirred for 6 hours and then allowed to stand for 24 hours to obtain a first mixture. The first mixture is coated on the surface of the substrate and baked at 60°C for 15 minutes to form an adhesion promoting layer. By weight percentage, 10% is ethyl tetrasilicate, 15.6% is allyltrimethoxysilane, 0.2% is hydrochloric acid, 6% is water, and the balance is ethanol. The substrate is a 15cm radius turntable of a rotating disk resistance testing platform.

[0035] S2. Silica particles with a particle size of 500 nm, perfluorooctylethylene, 2-hydroxy-2-methyl-1-phenylpropanone, and ethanol are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 1kW ultraviolet light for 40s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 1%, perfluorooctylethylene is 20%, 2-hydroxy-2-methyl-1-phenylpropanone is 0.2%, and the balance is ethanol.

[0036] Example 3: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0037] S1. Ethyl orthosilicate, diallyl dimethoxysilane, hydrochloric acid, water, and ethanol are stirred for 6 hours and then allowed to stand for 24 hours to obtain a first mixture. The first mixture is coated on the surface of the substrate and baked at 80°C for 10 minutes to form an adhesion promoting layer. By weight percentage, 10% is ethyl orthosilicate, 25.4% is diallyl dimethoxysilane, 0.2% is hydrochloric acid, 6% is water, and the balance is ethanol. The substrate is a rotating disk resistance test platform with a radius of 15cm.

[0038] S2. Silica particles with a particle size of 500 nm, perfluorohexylethylene, 2-hydroxy-2-methyl-1-phenylpropanone, and ethanol are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 1kW ultraviolet light for 60s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 2%, perfluorohexylethylene is 20%, 2-hydroxy-2-methyl-1-phenylpropanone is 0.1%, and the balance is ethanol.

[0039] Example 4: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0040] S1. Tetraethyl orthosilicate, vinyltriethoxysilane, hydrochloric acid, water, and ethanol are stirred for 12 hours and then allowed to stand for 48 hours to obtain a first mixture. The first mixture is applied to the surface of the substrate and baked at 80°C for 10 minutes to form an adhesion promoting layer. By weight percentage, tetraethyl orthosilicate is 9.2%, vinyltriethoxysilane is 25.3%, hydrochloric acid is 0.4%, water is 8%, and the balance is ethanol. The substrate is a rotating disk resistance test platform with a radius of 15cm.

[0041] S2. Silica particles with a particle size of 200nm, perfluorooctyl ethylene, diphenyl ethyl ketone, and ethanol are stirred in the dark until they are uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 2kW ultraviolet light for 60s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 2%, perfluorooctyl ethylene is 20%, diphenyl ethyl ketone is 0.5%, and the balance is ethanol.

[0042] Example 5: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0043] S1. Tetraethyl orthosilicate, allyltrimethoxysilane, hydrochloric acid, water, and ethanol are stirred for 6 hours and then allowed to stand for 24 hours to obtain a first mixture. The first mixture is coated on the surface of the substrate and baked at 80°C for 10 minutes to form an adhesion promoting layer. By weight percentage, tetraethyl orthosilicate is 10%, allyltrimethoxysilane is 25.4%, hydrochloric acid is 0.2%, water is 6%, and the balance is ethanol. The substrate is a rotating disk resistance test platform with a radius of 15cm.

[0044] S2. Silica particles with a particle size of 200 nm, perfluorodecylethylene, 2-hydroxy-2-methyl-1-phenylpropanone, and ethanol are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 2kW ultraviolet light for 60s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 2%, perfluorodecylethylene is 25%, 2-hydroxy-2-methyl-1-phenylpropanone is 0.1%, and the balance is ethanol.

[0045] Compare with Example 1:

[0046] The difference between Comparative Example 1 and Example 1 is that step S1 is not included. Specifically, silica particles with a particle size of 500 nm, perfluorooctylethylene, 2-hydroxy-2-methyl-1-phenylpropanone, and ethanol are stirred in the dark until they are mixed evenly to obtain a mixture. The mixture is then coated onto the surface of a substrate, which is a rotating disk resistance test platform with a radius of 15 cm. The substrate is cured with 1 kW ultraviolet light for 40 seconds to form a drag-reducing functional layer. By weight percentage, silica particles account for 1%, perfluorooctylethylene for 20%, 2-hydroxy-2-methyl-1-phenylpropanone for 0.2%, and the remainder is ethanol.

[0047] Compare with Example 2:

[0048] The difference between Comparative Example 2 and Example 1 is that step S2 is omitted. Specifically, tetraethyl orthosilicate, vinyltrimethoxysilane, hydrochloric acid, water, and ethanol are stirred for 6 hours and then allowed to stand for 24 hours to obtain a mixture. The mixture is then coated onto the surface of a substrate and baked at 60°C for 15 minutes to form an adhesion-promoting layer. By weight percentage, tetraethyl orthosilicate is 9.2%, vinyltrimethoxysilane is 12.8%, hydrochloric acid is 0.2%, water is 5.4%, and the balance is ethanol. The substrate is a 15cm radius rotating disk resistance testing platform. Comparative Example 3:

[0049] The only difference between Comparative Example 1 and Example 1 is that the vinyltrimethoxysilane used in step S1 is replaced with ethyltrimethoxysilane.

[0050] Performance comparison test:

[0051] Resistance tests were conducted on Examples 1-5 and Control Examples 1-3 at a rotational speed of 700 r / min. The experimental results are shown in Table 1.

[0052] Table 1

[0053]

[0054]

[0055] As shown in Table 1, Examples 1-5 of the present invention all achieved drag reduction rates of over 5%, demonstrating significant drag reduction effects. However, Comparative Example 1, lacking an adhesion-promoting layer, failed to retain the drag-reducing functional layer on the substrate, resulting in virtually no drag reduction effect. Comparative Example 2, also lacking a drag-reducing functional layer, exhibited limited drag reduction from the adhesion-promoting layer. Furthermore, Comparative Example 3, lacking alkenyl active sites in its adhesion-promoting layer, failed to achieve a good drag reduction effect because the drag-reducing functional layer could not chemically bond with it.

[0056] Example 6: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0057] S1. Ethyl orthosilicate, vinyltrimethoxysilane, acetic acid, water, and isopropanol are stirred for 12 hours and then allowed to stand for 72 hours to obtain a first mixture. The first mixture is applied to the surface of the substrate and baked at 40°C for 30 minutes to form an adhesion promoting layer. By weight percentage, 8% isosilicate, 12% is vinyltrimethoxysilane, 0.1% is acetic acid, 2% is water, and the balance is isopropanol. The substrate is a 15cm radius turntable of a rotating disk resistance testing platform.

[0058] S2. Silica particles with a particle size of 1000 nm, perfluorooctyl ethylene, α-hydroxyalkyl phenyl ketone, and ethyl acetate are stirred in the dark until they are uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 3kW ultraviolet light for 30s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 4%, perfluorooctyl ethylene is 25%, α-hydroxyalkyl phenyl ketone is 2%, and the balance is ethyl acetate.

[0059] Example 7: Preparation of an organosilicon composite drag-reducing coating according to the following steps:

[0060] S1. Ethyl orthosilicate, vinyltrimethoxysilane, formic acid, water, and petroleum ether are stirred for 4 hours and then allowed to stand for 30 hours to obtain a first mixture. The first mixture is applied to the surface of the substrate and baked at 50°C for 20 minutes to form an adhesion promoting layer. By weight percentage, 12% is ethyl orthosilicate, 38% is vinyltrimethoxysilane, 0.5% is formic acid, 10% is water, and the balance is petroleum ether. The substrate is a rotating disk resistance test platform with a radius of 15cm.

[0061] S2. 800nm ​​silica particles, perfluorooctyl ethylene, diphenyl ethyl ketone, and petroleum ether are stirred in the dark until they are uniformly mixed to obtain a second mixture. The second mixture is coated on the surface of the adhesion promoter layer obtained in step S1 and cured with 2kW ultraviolet light for 600s to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating composed of an adhesion promoter layer and a drag-reducing functional layer is obtained. By weight percentage, silica particles are 1%, perfluorooctyl ethylene is 5%, diphenyl ethyl ketone is 0.1%, and the balance is petroleum ether.

[0062] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the described embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims.

Claims

1. A method for preparing an organosilicon composite drag-reducing coating, characterized in that, Includes the following steps: S1. Tetraethyl orthosilicate, alkenylsilane, catalyst, water, and a first solvent are stirred and allowed to stand to obtain a first mixture. The first mixture is then coated onto the surface of a substrate and heated to form an adhesion-promoting layer. In step S1, by weight percentage, tetraethyl orthosilicate is 8-12%, alkenylsilane is 12-38%, catalyst is 0.1-0.5%, water is 2-10%, and the balance is the first solvent. The alkenylsilane is one or more of vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, and diallyldimethoxysilane. The catalyst is one or more of formic acid, acetic acid, and hydrochloric acid. The thickness of the adhesion-promoting layer is 1-25 µm. S2. Silica particles, perfluoroalkylethylene, a UV curing agent, and a second solvent are stirred in the dark until uniformly mixed to obtain a second mixture. The second mixture is then coated onto the surface of the adhesion promoter layer obtained in step S1, and UV-cured to form a drag-reducing functional layer. Finally, an organosilicon composite drag-reducing coating consisting of an adhesion promoter layer and a drag-reducing functional layer is obtained. In step S2, by weight percentage, silica particles are 1-4%, perfluoroalkylethylene is 5-25%, a UV curing agent is 0.1-2%, and the remainder is the second solvent. The perfluoroalkylethylene is one or more of perfluorooctylethylene, perfluorohexylethylene, and perfluorodecylethylene. The UV curing power is 1-3 kW, and the UV curing time is 30-600 s. The thickness of the drag-reducing functional layer is 1-25 µm. The static contact angle of the organosilicon composite drag-reducing coating is greater than 150°, and the drag reduction rate is 2-10%.

2. The method for preparing an organosilicon composite drag-reducing coating according to claim 1, characterized in that, In step S1, the first solvent is one or more of ethanol, isopropanol, and petroleum ether.

3. The method for preparing an organosilicon composite drag-reducing coating according to claim 1, characterized in that, In step S1, the stirring time is 4-12 hours, the standing time is 24-72 hours, the baking temperature is 40-80℃, and the baking time is 10-30 minutes.

4. The method for preparing an organosilicon composite drag-reducing coating according to claim 1, characterized in that, In step S2, the particle size of the silica particles is 200-1000 nm, the photocuring agent is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, diphenyl ethyl ketone, and α-hydroxyalkyl phenyl ketone, and the second solvent is one or more of ethanol, ethyl acetate, and petroleum ether.

5. The application of the organosilicon composite drag-reducing coating prepared by any one of claims 1-4 in the field of surface or underwater vehicles.

Images