A super-hydrophobic coating with excellent mechanical properties and preparation method thereof

Abstract

The present invention proposes a kind of super-hydrophobic coating of excellent mechanical property and preparation method thereof, belong to hydrophobic coating technical field.The super-hydrophobic coating of the present invention includes bottom layer and top layer arranged sequentially from bottom to top, and the bottom layer raw material includes fluorine-boron modified phenolic resin, phenolic resin and micro-nano structure particles, and the top layer raw material includes fluorine-boron modified phenolic resin, phenolic resin and hydrophobically modified micro-nano structure particles, and the mass ratio of micro-nano structure particles in the bottom layer and hydrophobically modified micro-nano structure particles in the top layer is (0.2~0.6): 1.The present invention can well improve mechanical property and stability by adjusting the composition and ratio of micro-nano structure particles in coating, so as to obtain the super-hydrophobic coating with good mechanical property, and preparation method is simple, cost is relatively low, while improving coating mechanical stability, the wettability of coating will not be negatively affected.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrophobic coatings, and in particular relates to a super-hydrophobic coating with excellent mechanical properties and a preparation method thereof. Background Art

[0002] Super-hydrophobicity refers to the phenomenon that the contact angle of a water droplet stationary on the surface of an object is greater than 150° and the rolling angle is less than 10°. Super-hydrophobic surfaces have good application prospects in the fields of corrosion protection, self-cleaning, anti-icing, and directional transport of liquids. The preparation methods of commonly used super-hydrophobic coatings include electrochemical deposition, template method, sol-gel method, etching method, self-assembly method, etc. Most of these preparation methods have complex processes, cumbersome procedures, and poor mechanical wear resistance of the coating. The problem of poor mechanical stability of super-hydrophobic coatings has become a key problem that restricts its practical application.

[0003] Existing methods for optimizing the surface mechanical properties of super-hydrophobic coatings often negatively affect their super-hydrophobic properties, and the process is complex and costly. It is of great practical significance to seek simple, easy-to-use and low-cost methods that do not negatively affect the wetting properties of super-hydrophobic coatings and can improve the mechanical stability of the coating. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a super-hydrophobic coating with excellent mechanical properties and a preparation method thereof.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A super-hydrophobic coating with excellent mechanical properties comprises a bottom layer and a surface layer arranged sequentially from bottom to top, wherein the bottom layer comprises a fluorinated boron-modified phenolic resin, a phenolic resin, and micro-nanostructured particles, and the surface layer comprises a fluorinated boron-modified phenolic resin, a phenolic resin, and hydrophobically modified micro-nanostructured particles.

[0008] The mass ratio of the micro-nano structure particles in the bottom layer to the hydrophobically modified micro-nano structure particles in the surface layer is (0.2-0.6):1.

[0009] The second technical solution of the present invention:

[0010] A method for preparing a super-hydrophobic coating with excellent mechanical properties comprises the following steps: spraying a primer and a topcoat on a substrate surface in a layered spraying manner, forming a primer and a topcoat on the substrate surface in sequence, and drying and curing the super-hydrophobic coating to obtain the super-hydrophobic coating with excellent mechanical properties;

[0011] The primer is prepared by using a fluorine-containing boron-modified phenolic resin and a phenolic resin mixture as the main body, embedding micro-nanostructured particles, and dispersing them in a solvent;

[0012] The surface coating is prepared by taking fluorine-containing boron-modified phenolic resin and a phenolic resin mixture as a main body, embedding hydrophobically modified micro-nano structure particles, and dispersing them in a solvent.

[0013] Furthermore, the micro-nanostructured particles in the primer include one or more of hydroxylated multi-walled carbon nanotubes and nanocellulose. These micro-nanostructured particles disperse in the resin and enhance the mechanical properties of the resin matrix. The mass ratio of the fluorine-containing boron-modified phenolic resin to the phenolic resin is 1:(2.5-3.5), and the mass ratio of the micro-nanostructured particles to the fluorine-containing boron-modified phenolic resin is 2:5.

[0014] Furthermore, the surface coating comprises hydrophobically modified micro-nanostructured particles comprising one or more of ZrO2, SiO2, Al2O3, TiO2, hydroxylated multi-walled carbon nanotubes, nanocellulose, Fe3O4, Fe2O3, and ZnO modified with fluorinated siloxane. These hydrophobically modified micro-nanostructured particles disperse in the resin, forming a micro-nanocomposite structure at different levels and enhancing the coating's hydrophobic properties. The mass ratio of the fluorinated boron-modified phenolic resin to the phenolic resin is 1:(2.5-3.5), and the mass ratio of the hydrophobically modified micro-nanostructured particles to the fluorinated boron-modified phenolic resin is 7:5.

[0015] Furthermore, the fluorine-containing silicone is 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0016] Furthermore, the preparation method of the hydrophobically modified micro-nanostructured particles comprises the following steps:

[0017] adding the micro-nanostructured particles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to a solvent (anhydrous ethanol or acetone), adding ammonia water, and stirring at 30° C. for 0.5 to 3 hours to obtain the hydrophobically modified micro-nanostructured particles;

[0018] The volume ratio of the ammonia water to the solvent is 1: (3-5), the volume ratio of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the solvent is 1: (100-150), and the mass ratio of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the micro-nanostructured particles is 1: (0.1-1).

[0019] Furthermore, the solvents used in the primer and the surface coating are both anhydrous ethanol or acetone.

[0020] Furthermore, the method specifically includes the following steps:

[0021] (1) grinding, polishing and ultrasonic cleaning the substrate surface;

[0022] (2) Mix the micro-nanostructured particles, solvent (anhydrous ethanol or acetone) and ammonia water, and stir them magnetically at 30°C for 1 hour, which is recorded as solution A. Add the boron-modified phenolic resin, phenolic resin, silane coupling agent, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the solvent (anhydrous ethanol or acetone), and stir them magnetically at 30°C for 1 hour, which is recorded as solution B. Pour solution A into solution B, and stir them magnetically at 30°C for 1 to 2 hours to obtain a primer.

[0023] The micro-nanostructured particles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane are added to a solvent (anhydrous ethanol or acetone), and ammonia water is added, and the mixture is magnetically stirred in a water bath at 30°C for 0.5 to 3 hours to obtain a hydrophobically modified micro-nanostructured particle emulsion, which is recorded as solution C. The boron-modified phenolic resin, phenolic resin, and silane coupling agent are added to the solvent (anhydrous ethanol or acetone), and the mixture is magnetically stirred in a water bath at 30°C for 30 minutes. After that, 1H,1H,2H,2H-perfluorodecyltriethoxysilane is added, and the mixture is magnetically stirred in a water bath at 30°C for 30 minutes, which is recorded as solution D. Solution C is poured into solution D, and the mixture is magnetically stirred at 30°C for 1 hour to obtain a surface coating.

[0024] (3) spraying the base coating on the surface of the substrate obtained in step (1), drying the base coating to form a semi-cured layer, and then spraying the top coating, and continuing to dry the top coating until the top layer is completely cured to obtain the super-hydrophobic coating with excellent mechanical properties.

[0025] Furthermore, in step (1), the substrate includes metal and non-metal materials such as aluminum alloy, magnesium alloy, carbon steel, stainless steel, glass, and ceramics.

[0026] Furthermore, in step (1), the polishing treatment is performed by polishing with SiC sandpaper, and the particle sizes of the sandpaper are 100, 400, 600, 800, 1000, and 1500 meshes, respectively; and the ultrasonic cleaning treatment is performed by ultrasonic cleaning in deionized water, anhydrous ethanol, and acetone, respectively, for 15 minutes.

[0027] Furthermore, in step (2), the temperature of the water bath heating and stirring is 30° C., and the time is 0.5 to 3 hours.

[0028] Furthermore, in step (3), the spraying flow rate of the spray gun is 0.1-1 mL / s, the spray gun is sprayed at a distance of 10-30 cm from the substrate, the spray gun pressure is 0.2-1 MPa, and the spray gun movement speed is 2 cm / s.

[0029] Furthermore, in step (3), the bottom layer is dried at 130° C. to 150° C. for 3 to 5 minutes to form a semi-cured layer.

[0030] Furthermore, in step (3), the product is dried at 150° C. for 1 to 3 hours until the surface layer is completely solidified.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects:

[0032] (1) The present invention mixes boron-modified phenolic resin with phenolic resin and adopts a layered spraying method to obtain a super-hydrophobic coating with a double-layer composite structure. According to the different performance requirements of the bottom layer and the surface layer, the composition and proportion of the micro-nanostructured particles in the coating are adjusted. The polymer filler wraps the micro-nanostructured particles with different concentration gradients, which protects the ability of the micro-nanostructure to resist mechanical wear and can greatly improve the stability of the mechanical properties, thereby obtaining a super-hydrophobic coating with good mechanical properties.

[0033] (2) The super-hydrophobic coating prepared by the present invention has good mechanical stability and bonding strength, which is beneficial to improving the durability, corrosion resistance, and acid and alkali resistance of the substrate under some complex working conditions.

[0034] (3) The preparation method of the present invention is simple and easy to implement, with low cost. It improves the mechanical stability of the coating without negatively affecting the wettability of the coating. In addition, compared with most other existing methods, the preparation method is simple, the reagents involved are cheap, the preparation cycle is short, the temperature requirement is low, and it is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0036] Figure 1 Schematic diagram of the process flow of the super-hydrophobic coating with excellent mechanical properties of the present invention;

[0037] Figure 2 Schematic diagram (a) of the preparation process of P-U75V-FS in Example 1 of the present invention and schematic diagram (b) of the hydrophobic modification principle of the hydrophobically modified micro-nanostructured particles in step (2);

[0038] Figure 3 This is a scanning electron microscope (SEM) image of P-U75V-FS prepared in Example 1 of the present invention;

[0039] Figure 4 Graphs showing static contact angles between a water droplet and a surface of the super-hydrophobic coatings prepared in Examples 1-3 of the present invention;

[0040] Figure 5 Graph showing the static contact angles of a water droplet and a surface after abrasion testing of the super-hydrophobic coatings prepared in Examples 1-3 of the present invention;

[0041] Figure 6 Tafel curves of the super-hydrophobic coatings prepared in Examples 1-3 and untreated carbon steel U75V;

[0042] Figure 7 These are static contact angle diagrams of the coatings prepared in Comparative Examples 1-3 of the present invention between a water droplet and a surface. DETAILED DESCRIPTION

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0045] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0046] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0047] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0048] The embodiment of the present invention provides a super-hydrophobic coating with excellent mechanical properties, comprising a bottom layer and a surface layer arranged sequentially from bottom to top, wherein the bottom layer raw materials include fluorinated boron-modified phenolic resin, phenolic resin and micro-nanostructured particles, and the surface layer raw materials include fluorinated boron-modified phenolic resin, phenolic resin and hydrophobically modified micro-nanostructured particles;

[0049] The mass ratio of the micro-nano structure particles in the bottom layer to the hydrophobically modified micro-nano structure particles in the surface layer is (0.2-0.6):1.

[0050] The present invention also provides a method for preparing a super-hydrophobic coating with excellent mechanical properties, comprising the following steps: spraying a primer and a topcoat on a substrate surface in a layered spraying manner, forming a primer and a topcoat on the substrate surface in sequence, and drying and curing the super-hydrophobic coating to obtain the super-hydrophobic coating with excellent mechanical properties;

[0051] The primer is prepared by using a fluorine-containing boron-modified phenolic resin and a phenolic resin mixture as the main body, embedding micro-nanostructured particles, and dispersing them in a solvent;

[0052] The surface coating is prepared by taking fluorine-containing boron-modified phenolic resin and a phenolic resin mixture as a main body, embedding hydrophobically modified micro-nano structure particles, and dispersing them in a solvent.

[0053] In a preferred embodiment of the present invention, in the primer, the micro-nanostructured particles include one or more of hydroxylated multi-walled carbon nanotubes and nanocellulose, the particle size of the micro-nanostructured particles is ≤25 μm, the mass ratio of the fluorine-containing boron-modified phenolic resin and the phenolic resin is 1:(2.5~3.5), and the mass ratio of the micro-nanostructured particles to the fluorine-containing boron-modified phenolic resin is 2:5.

[0054] In a preferred embodiment of the present invention, the surface coating comprises one or more of ZrO2, SiO2, Al2O3, TiO2, hydroxylated multi-walled carbon nanotubes, cellulose, Fe3O4, Fe2O3 and ZnO modified with fluorinated silicone, the particle size of the hydrophobically modified micro-nanostructured particles is 20 nm, the mass ratio of the fluorinated boron-modified phenolic resin to the phenolic resin is 1:(2.5-3.5), and the mass ratio of the hydrophobically modified micro-nanostructured particles to the fluorinated boron-modified phenolic resin is 7:5.

[0055] In a preferred embodiment of the present invention, the fluorine-containing siloxane is 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0056] In a preferred embodiment of the present invention, the method for preparing the hydrophobically modified micro-nanostructured particles comprises the following steps:

[0057] adding the micro-nanostructured particles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to a solvent (anhydrous ethanol or acetone), adding ammonia water, and stirring at 30° C. for 0.5 to 3 hours to obtain the hydrophobically modified micro-nanostructured particles;

[0058] The volume ratio of the ammonia water to the solvent is 1: (3-5), the volume ratio of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the solvent is 1: (100-150), and the mass ratio of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the micro-nanostructured particles is 1: (0.1-1).

[0059] In a preferred embodiment of the present invention, the solvents used in the primer and the surface coating are both anhydrous ethanol or acetone.

[0060] In a preferred embodiment of the present invention, the following steps are specifically included:

[0061] (1) grinding, polishing and ultrasonic cleaning the substrate surface;

[0062] (2) Mix the micro-nanostructured particles, solvent (anhydrous ethanol or acetone) and ammonia water, and stir them magnetically at 30°C for 1 hour, which is recorded as solution A. Add the boron-modified phenolic resin, phenolic resin, silane coupling agent, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the solvent (anhydrous ethanol or acetone), and stir them magnetically at 30°C for 1 hour, which is recorded as solution B. Pour solution A into solution B, and stir them magnetically at 30°C for 1 to 2 hours to obtain a primer.

[0063] The micro-nanostructured particles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane are added to a solvent (anhydrous ethanol or acetone), and ammonia water is added, and magnetic stirring is carried out at 30°C for 0.5 to 3 hours to obtain a hydrophobically modified micro-nanostructured particle emulsion, which is recorded as solution C. The boron-modified phenolic resin, phenolic resin, and silane coupling agent are added to the solvent (anhydrous ethanol or acetone), and magnetic stirring is carried out at 30°C for 30 minutes. After that, 1H,1H,2H,2H-perfluorodecyltriethoxysilane is added, and magnetic stirring is carried out at 30°C for 30 minutes, which is recorded as solution D. Solution C is poured into solution D, and magnetic stirring is carried out at 30°C for 1 hour to obtain a surface coating.

[0064] (3) spraying the base coating on the surface of the substrate obtained in step (1), drying the base coating to form a semi-cured layer, and then spraying the top coating, and continuing to dry the top coating until the top layer is completely cured to obtain the super-hydrophobic coating with excellent mechanical properties.

[0065] The process flow diagram of the super hydrophobic coating with excellent mechanical properties of the present invention is shown in Figure 1 .

[0066] In a preferred embodiment of the present invention, in step (1), the substrate includes metal and non-metal materials such as aluminum alloy, magnesium alloy, carbon steel, stainless steel, glass, and ceramics.

[0067] In a preferred embodiment of the present invention, in step (1), the polishing treatment is performed by polishing with SiC sandpaper, and the particle sizes of the sandpaper are 100, 400, 600, 800, 1000, and 1500 meshes, respectively; and the ultrasonic cleaning treatment is performed by ultrasonic cleaning in deionized water, anhydrous ethanol, and acetone, respectively, for 15 minutes.

[0068] In a preferred embodiment of the present invention, in step (2), the temperature of the water bath heating and stirring is 30° C., and the time is 0.5 to 3 hours.

[0069] In a preferred embodiment of the present invention, in step (3), the spraying flow rate of the spray gun is 0.1-1 mL / s, the spray gun sprays at a distance of 10-30 cm from the substrate, the spray gun pressure is 0.2-1 MPa, and the spray gun movement speed is 2 cm / s.

[0070] In a preferred embodiment of the present invention, in step (3), drying is performed at 130° C. to 150° C. for 3 to 5 minutes until a semi-cured layer is formed on the bottom layer.

[0071] In a preferred embodiment of the present invention, in step (3), drying is performed at 150° C. for 1 to 3 hours until the surface layer is completely solidified.

[0072] All raw materials used in the examples of the present invention were purchased from the market.

[0073] The technical solution of the present invention is further illustrated by the following examples.

[0074] Example 1

[0075] (1) Carbon steel U75V was polished with SiC sandpaper of 100, 400, 600, 800, 1000, and 1500 meshes, and then ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 15 min. The resulting sample was designated P-U75V.

[0076] (2) 0.2 g of nanocellulose, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C (water bath) for 1 h, which was recorded as solution A. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550), and 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 1 h, which was recorded as solution B. Solution A was poured into solution B and magnetically stirred at 30 ° C (water bath) for 1 h to obtain a primer;

[0077] 0.4 g of nanocellulose, 0.2 g of nano ZrO2, 0.1 g of nano SiO2, 30 mL of ethanol, and 10 mL of ammonia water were mixed at 30 ° C (water bath) with magnetic stirring for 30 min, and then 0.6 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was magnetically stirred at 30°C (water bath) for 30 minutes to obtain a hydrophobically modified micro-nanostructure particle emulsion, which was recorded as solution C. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, and 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550) were added to 10 mL of anhydrous ethanol and magnetically stirred at 30°C for 30 minutes. Then, 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added and magnetically stirred at 30°C (water bath) for 30 minutes, which was recorded as solution D. Solution C was poured into solution D and magnetically stirred at 30°C for 1 hour to obtain a surface coating.

[0078] (3) The bottom coating prepared by spraying the P-U75V surface obtained in step (1) was firstly prepared, and then dried at 130°C for 3 min to wait for the bottom coating to form a semi-cured surface (denoted as P-U75V-F), and then the top coating prepared by spraying was applied on the semi-cured surface, and finally placed in a drying oven at 150°C for 1 h, and dried until the surface was completely cured to obtain a super hydrophobic coating with excellent mechanical properties, denoted as P-U75V-FS-1, the spraying flow rate of the spray gun was 0.1 mL / s, the spray gun was sprayed at a distance of 20 cm from the substrate, the spray gun pressure was 0.2 MPa, and the spray gun movement speed was 2 cm / s.

[0079] Example 2 (the mass ratio of the micro-nanostructured particles in the bottom layer to the hydrophobically modified micro-nanostructured particles in the surface layer is 0.6:1)

[0080] (1) Carbon steel U75V was polished with SiC sandpaper of 100, 400, 600, 800, 1000, and 1500 meshes, and then ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 15 min. The resulting sample was designated P-U75V.

[0081] (2) 0.6 g of nanocellulose, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C for 1 h, which was recorded as solution A. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550), and 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 1 h, which was recorded as solution B. Solution A was poured into solution B and magnetically stirred at 30 ° C for 2 h to obtain a primer;

[0082] 0.5 g of nanocellulose, 0.3 g of nano ZrO2, 0.2 g of nano SiO2, 30 mL of ethanol, and 10 mL of ammonia water were mixed at 30°C and magnetically stirred for 30 min, and then 0.6 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added and magnetically stirred at 30°C for 30 min to obtain a hydrophobically modified micro-nanostructure particle emulsion, which was recorded as solution C. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, and 0.1 g of silane coupling agent were added to 10 mL of anhydrous ethanol and magnetically stirred at 30°C for 30 min, and then 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added and magnetically stirred at 30°C for 30 min, which was recorded as solution D. Solution C was poured into solution D and magnetically stirred at 30°C for 1 h to obtain a surface coating.

[0083] (3) The primer coating prepared by spraying the P-U75V surface obtained in step (1) was firstly prepared, and the primer coating was dried at 130°C for 3 min to wait for the primer coating to form a semi-cured surface, and then the surface coating prepared by spraying was applied on the semi-cured surface. Finally, the coating was placed in a drying oven at 160°C for 1 h and dried until the surface was completely cured to obtain a super hydrophobic coating with excellent mechanical properties (denoted as P-U75V-FS-2). The spraying flow rate of the spray gun was 0.1 mL / s, and the spray gun was fixed at a distance of 30 cm from the substrate for spraying. The spray gun pressure was 0.2 MPa and the spray gun moving speed was 2 cm / s.

[0084] Example 3 (the mass ratio of the micro-nanostructured particles in the bottom layer to the hydrophobically modified micro-nanostructured particles in the surface layer is 0.2:1)

[0085] (1) Carbon steel U75V was polished with SiC sandpaper of 100, 400, 600, 800, 1000, and 1500 meshes, and then ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 15 min. The resulting sample was designated P-U75V.

[0086] (2) 0.2 g of nanocellulose, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C for 1 h, which was recorded as solution A. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550), and 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 1 h, which was recorded as solution B. Solution A was poured into solution B and magnetically stirred at 30 ° C for 1 h to obtain a primer;

[0087] 0.5 g of nanocellulose, 0.3 g of nano ZrO2, 0.2 g of nano SiO2, 30 mL of ethanol, and 10 mL of ammonia water were mixed at 30°C and magnetically stirred for 30 min, and then 0.6 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added and magnetically stirred at 30°C for 30 min to obtain a hydrophobically modified micro-nanostructure particle emulsion, which was recorded as solution C. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, and 0.1 g of silane coupling agent were added to 10 mL of anhydrous ethanol and magnetically stirred at 30°C for 30 min, and then 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added and magnetically stirred at 30°C for 30 min, which was recorded as solution D. Solution C was poured into solution D and magnetically stirred at 30°C for 1 h to obtain a surface coating.

[0088] (3) The primer coating prepared by spraying the P-U75V surface obtained in step (1) was firstly prepared, and the primer coating was dried at 150°C for 3 min to wait for the primer coating to form a semi-cured surface, and then the surface coating prepared by spraying was applied on the semi-cured surface. Finally, the coating was placed in a drying oven at 150°C for 1 h and dried until the surface was completely cured to obtain a super hydrophobic coating with excellent mechanical properties (denoted as P-U75V-FS-3). The spraying flow rate of the spray gun was 1 mL / s, the spray gun was fixed at a distance of 10 cm from the substrate, the spray gun pressure was 1 MPa, and the spray gun moving speed was 2 cm / s.

[0089] Performance Testing

[0090] The schematic diagram of the preparation process of P-U75V-FS-1 in Example 1 of the present invention is shown in Figure 2 (a) in step (2), the hydrophobic modification principle of the hydrophobically modified micro-nanostructured particles is shown in Figure 2 (b) in the.

[0091] The scanning electron microscope (SEM) image of P-U75V-FS-1 prepared in Example 1 of the present invention is shown in FIG. Figure 3 As can be seen, the coating surface exhibits a complex multi-scale micro-nanostructure, presenting an overall porous structure with numerous irregular nano-spherical structures scattered on the pore walls. Each nano-sphere is composed of aggregated nanoparticles. These complex structures provide a large number of "air pockets" when the surface contacts liquid, which can block the liquid from invading the coating surface. The multi-scale micro-nanostructures can also increase the contact angle of the superhydrophobic coating. Even after mechanical friction, even if the surface nanoparticles are worn flat, the micro-nanostructures at other scales can maintain the superhydrophobicity of the coating.

[0092] The static contact angle diagram of the water droplet and the surface of the super hydrophobic coating prepared in Examples 1-3 of the present invention is shown in FIG. Figure 4It can be seen that the static contact angles (WCA) of water droplets on the carbon steel surfaces after spray coating in Examples 1-3 are 166.5° (the test water droplet is 4 μL), 165.3° (the test water droplet is 4 μL) and (WCA) are 165° (the test water droplet is 4 μL), respectively, indicating that superhydrophobic surface properties have been obtained.

[0093] The super-hydrophobic coatings prepared in Examples 1-3 were subjected to a surface coating wear test. Under the condition of bearing a weight of 200 g, they were rubbed 130 times with 1000-grit sandpaper (each friction distance was 20 cm). The static contact angle between the water droplet and the surface is shown in FIG. Figure 5 It can be seen that the static contact angle value of the water droplet in Example 1 is reduced to 151.1°, the static contact angle value of the water droplet in Example 2 is reduced to 150.5°, and the static contact angle value of the water droplet in Example 3 is reduced to 151.5°, indicating that the super-hydrophobic coatings prepared in Examples 1-3 of the present invention have good mechanical properties.

[0094] The super-hydrophobic coatings prepared in Examples 1-3 and the untreated carbon steel U75V in Example 1 were subjected to electrochemical tests. The test solution was 3.5% NaCl solution. The Tafel curves of the two were shown in FIG. Figure 6 , it can be seen that the self-corrosion current density of the super-hydrophobic coating after coating in Example 1 is 4.339×10 -8 A / cm 2 The self-corrosion current density of Example 2 is 1.046×10 -8 A / cm 2 The self-corrosion current density of Example 3 is 8.757×10 -9 A / cm 2 , while the self-corrosion current density of untreated carbon steel U75V is 8.657×10 -7 A / cm 2 The self-corrosion current density of the super-hydrophobic coating prepared in Examples 1-3 of the present invention is lower than that of the substrate (untreated carbon steel U75V), which proves that the super-hydrophobic coating of the present invention has good corrosion resistance.

[0095] Comparative Example 1

[0096] (1) Carbon steel U75V was polished with SiC sandpaper of 100, 400, 600, 800, 1000, and 1500 meshes, and then ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 15 min. The resulting sample was designated P-U75V.

[0097] (2) 0.4 g of nanocellulose, 0.2 g of nano ZrO2, 0.1 g of nano SiO2, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C for 30 min, and then 0.6 g of 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane was added and magnetically stirred at 30 ° C for 30 min to obtain a hydrophobically modified micro-nanostructure particle emulsion, which was recorded as solution C. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, and 0.1 g of γ-aminopropyl triethoxysilane (silane coupling agent KH550) were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 30 min, and then 0.3 g of 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane was added and magnetically stirred at 30 ° C for 30 min, which was recorded as solution D. Solution C was poured into solution D and magnetically stirred at 30 ° C for 1 hour to obtain a coating;

[0098] (3) The coating prepared by spraying the P-U75V surface obtained in step (1) was first placed in a 150° C. drying oven for curing for 1 h, and dried until the surface was completely cured to obtain a super-hydrophobic coating. The spraying flow rate of the spray gun was 0.1 mL / s, and the spray gun was sprayed at a distance of 20 cm from the substrate. The spray gun pressure was 0.2 MPa and the spray gun movement speed was 2 cm / s.

[0099] Comparative Example 2

[0100] (1) Carbon steel U75V was polished with SiC sandpaper of 100, 400, 600, 800, 1000, and 1500 meshes, and then ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 15 min. The resulting sample was designated P-U75V.

[0101] (2) 0.2 g of nanocellulose, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C for 1 h, which was recorded as solution A. 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550), and 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 1 h, which was recorded as solution B. Solution A was poured into solution B and magnetically stirred at 30 ° C for 1 h to obtain a coating;

[0102] (3) The coating prepared by spraying the P-U75V surface obtained in step (1) was first dried at 130° C. for 3 min to wait for the bottom coating to form a semi-cured surface, and then placed in a drying oven at 150° C. for curing for 1 h, and dried until the surface was completely cured to obtain a super-hydrophobic coating. The spraying flow rate of the spray gun was 0.1 mL / s, and the spray gun was sprayed at a distance of 20 cm from the substrate. The spray gun pressure was 0.2 MPa and the spray gun movement speed was 2 cm / s.

[0103] Comparative Example 3

[0104] The same as Example 1, except that the surface coating was prepared according to the following method: 0.2 g of nanocellulose, 30 mL of ethanol, and 10 mL of ammonia water were mixed and magnetically stirred at 30 ° C for 1 h, recorded as solution A, 0.5 g of boron-modified phenolic resin, 1.5 g of phenolic resin, 0.1 g of γ-aminopropyltriethoxysilane (silane coupling agent KH550), and 0.3 g of 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to 10 mL of anhydrous ethanol and magnetically stirred at 30 ° C for 1 h, recorded as solution B, solution A was poured into solution B, and magnetically stirred at 30 ° C for 1 h to obtain a surface coating;

[0105] The remaining steps and dosages are the same as those in Example 1.

[0106] Performance Testing

[0107] The static contact angle diagrams of the coatings prepared in Comparative Examples 1-3 of the present invention with respect to the water droplet and the surface are shown in FIG. Figure 7 , it can be seen that the static contact angle (WCA) of water droplets on the carbon steel surface after spray coating of Comparative Examples 1-3 is 165.2 ° (test water droplet is 4 μ L), 97 ° (test water droplet is 4 μ L) and (WCA) is 107 ° (test water droplet is 4 μ L), only Comparative Example 1 has a super-hydrophobic effect. Further, the super-hydrophobic coating prepared in Comparative Example 1 is subjected to a surface coating wear test. When bearing a 200 g weight, it is rubbed cyclically with 1000 mesh sandpaper (each friction distance is 20 cm). After 10 cycles of friction, the contact angle is reduced to 146.2 °, indicating that the super-hydrophobic coating prepared in Comparative Example 1 of the present invention has a super-hydrophobic effect, but its ability to resist mechanical wear is relatively low, and its mechanical properties are unstable.

[0108] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for preparing a super-hydrophobic coating with excellent mechanical properties, characterized in that, The following steps are involved: (1) grinding, polishing and ultrasonic cleaning the substrate surface; (2) Mixing the micro-nanostructured particles, solvent, and ammonia water, and magnetically stirring at 30°C for 1 hour, which is recorded as solution A; adding the boron-modified phenolic resin, phenolic resin, silane coupling agent, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the solvent, and magnetically stirring at 30°C for 1 hour, which is recorded as solution B; pouring solution A into solution B, and magnetically stirring at 30°C for 1 to 2 hours to obtain a primer; The micro-nanostructured particles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane were added to a solvent, and ammonia water was added, and the mixture was magnetically stirred at 30°C for 0.5 to 3 hours to obtain a hydrophobically modified micro-nanostructured particle emulsion, which was recorded as solution C. The boron-modified phenolic resin, phenolic resin, and silane coupling agent were added to the solvent, and the mixture was magnetically stirred at 30°C for 30 minutes. After that, 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added, and the mixture was magnetically stirred at 30°C for 30 minutes, which was recorded as solution D. Solution C was poured into solution D, and the mixture was magnetically stirred at 30°C for 1 hour to obtain a surface coating. (3) spraying the bottom coating on the surface of the substrate obtained in step (1), drying the bottom coating to form a semi-cured layer, and then spraying the top coating, and continuing to dry the top coating until the surface is completely cured to obtain the super-hydrophobic coating with excellent mechanical properties; In the surface coating and the bottom coating, the solvent used is anhydrous ethanol or acetone; The mass ratio of the micro-nano structure particles in the bottom layer to the micro-nano structure particles in the surface layer is (0.2-0.6):1; In the primer, the mass ratio of the boronized modified phenolic resin to the phenolic resin is 1:(2.5-3.5); the mass ratio of the micro-nanostructured particles to the boronized modified phenolic resin is 2:5; In the surface coating, the mass ratio of the boronized modified phenolic resin to the phenolic resin is 1:(2.5-3.5), and the mass ratio of the micro-nanostructured particles to the boronized modified phenolic resin is 7:

5.

2. according to the preparation method of the super-hydrophobic coating with excellent mechanical property of claim 1, it is characterized in that, In the primer, the micro-nanostructured particles include one or more of hydroxylated multi-walled carbon nanotubes and nanocellulose; In the surface coating, the hydrophobically modified micro-nanostructured particles include one or more of fluorinated silicone-modified ZrO2, SiO2, Al2O3, TiO2, hydroxylated multi-walled carbon nanotubes, nanocellulose, Fe3O4, Fe2O3 and ZnO.

3. The preparation method of the super-hydrophobic coating with excellent mechanical properties according to claim 1, wherein In step (3), the spraying flow rate of the spray gun is 0.1-1 mL / s, the spray gun is sprayed at a distance of 10-30 cm from the substrate, the spray gun pressure is 0.2-1 MPa, and the spray gun movement speed is 2 cm / s.

4. The preparation method of the super-hydrophobic coating with excellent mechanical properties according to claim 1, wherein In step (3), the bottom layer is dried at 130° C. to 150° C. for 3 to 5 minutes to form a semi-cured layer.

5. The preparation method of the super-hydrophobic coating with excellent mechanical properties according to claim 1, wherein In step (3), the mixture is dried at 150° C. for 1 to 3 hours until the surface layer is completely solidified.

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