An anti-corrosion, anti-fouling and drag-reducing composite coating, its preparation method and application

Abstract

The present invention discloses an anti-corrosion, anti-fouling and drag-reducing composite coating, a preparation method thereof and an application. The anti-corrosion, anti-fouling and drag-reducing composite coating comprises a base layer, a corrosion barrier layer, a connection layer and a flexible anti-fouling layer which are sequentially formed on the surface of a substrate; wherein, the base layer comprises an adhesive resin, a positively charged polymer, a filler and a diluent; the corrosion barrier layer comprises a flexible polymer resin, a negatively charged polymer and two-dimensional nanosheets; the connection layer comprises an adhesive resin, a positively charged polymer, a filler and a connecting agent; the flexible anti-fouling layer comprises a flexible polymer resin and temperature-responsive polymer microcapsules encapsulating an anti-fouling agent. The anti-corrosion, anti-fouling and drag-reducing composite coating in the present invention has a strong bonding force with the substrate and also has anti-corrosion, anti-fouling and drag-reducing properties; meanwhile, the preparation method provided by the present invention has the advantages of wide application range, large-area coating, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine coating protection, and particularly relates to an anti-corrosion, anti-fouling and drag-reducing composite coating, a preparation method thereof and an application thereof. Background Art

[0002] In today's industrial field, the application of anti-corrosion and drag-reducing functional coatings has become a technology that has attracted much attention. With the acceleration of the industrialization process and the improvement of environmental protection awareness, the demand for corrosion prevention and reduction of frictional resistance in various fields is becoming increasingly urgent. Especially in the fields of marine transportation, ocean engineering, shipbuilding and water treatment, marine organisms and seawater corrosion have brought serious problems to the navigation body. To address this challenge, researchers have been continuously exploring innovative anti-corrosion and drag-reducing functional coating technologies. By combining anti-corrosion materials with drag-reducing technologies, long-term protection of the surface of equipment and ships and reduction of frictional resistance can be achieved. Currently, flexible drag-reducing technology is a key research direction in drag-reducing technology, and its drag-reducing mechanism relies on the flexible effect to suppress and absorb the wave change of water pressure and delay the transition from laminar flow to turbulent flow, thereby achieving an effective drag-reducing effect. However, in practical applications, it is difficult to cope with complex and variable environments relying solely on the flexible mechanism, such as the corrosion problem of the substrate under long-term seawater immersion cannot be avoided. Through multi-layer structure design, effectively integrating various compounds with special functions together to achieve the goal of synergistically enhancing the integration of anti-corrosion and drag-reducing functions is an innovative idea. In practical applications, such coatings with multiple functions can effectively cope with the changing environmental conditions in the ocean, extend the service life of ships and marine facilities, and promote the sustainable development of the marine transportation and water treatment industries. In the future, with the continuous progress of science and technology and the innovation of materials engineering, anti-corrosion and drag-reducing functional coatings will continue to develop and grow, bringing more innovation and economic benefits to the industrial community. Therefore, the application prospect of this coating in various fields is very broad, providing important technical support and guarantee for creating a cleaner and more efficient industrial environment for us. Summary of the Invention

[0003] The main object of the present invention is to provide an anti-corrosion, anti-fouling and drag-reducing composite coating, a preparation method thereof and an application thereof, so as to overcome the deficiencies of the prior art.

[0004] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0005] An embodiment of the present invention provides an anti-corrosion, anti-fouling and drag-reducing composite coating, which includes: a base layer, a corrosion barrier layer, a connection layer and a flexible anti-fouling layer formed in sequence on the surface of a substrate;

[0006] Among them, the base layer includes an adhesive resin, a positively charged polymer, a filler, and a diluent; the corrosion barrier layer includes a flexible polymer resin, a negatively charged polymer, and two-dimensional nanosheets; the connection layer includes an adhesive resin, a positively charged polymer, a filler, and a coupling agent; the flexible antifouling layer includes a flexible polymer resin and temperature-responsive polymer microcapsules encapsulating an antifouling agent; the positively charged polymer includes any one or a combination of two or more of polyvinylamine, polyaniline, poly(methacryloyloxyethyl trimethyl ammonium chloride), and polyacrylamide; the negatively charged polymer includes any one or a combination of two or more of polyglutamic acid, polyvinyl alcohol acid, and sodium polystyrene sulfonate.

[0007] The embodiment of the present invention also provides a preparation method of the above-mentioned anti-corrosion, anti-fouling and drag-reducing composite coating, which includes:

[0008] Applying a first base liquid containing at least an adhesive resin, a positively charged polymer, a filler, and a diluent to the surface of a substrate and performing a first curing treatment to form a base layer with a multi-level micro-nano structure;

[0009] Applying a second base liquid containing at least a polymer resin, a negatively charged polymer, two-dimensional nanosheets, and a diluent to the surface of the base layer and performing a second curing treatment to form a corrosion barrier layer;

[0010] Applying a third base liquid containing at least an adhesive resin, a positively charged polymer, a filler, a coupling agent, and a diluent to the surface of the corrosion barrier layer and performing a third curing treatment to form a connection layer;

[0011] And applying a fourth base liquid containing at least a flexible polymer resin, temperature-responsive polymer microcapsules encapsulating an antifouling agent, and a solvent to the surface of the connection layer and performing a fourth curing treatment to form a flexible antifouling layer, thereby obtaining an anti-corrosion, anti-fouling and drag-reducing composite coating.

[0012] The embodiment of the present invention also provides an application of the above-mentioned anti-corrosion, anti-fouling and drag-reducing composite coating in the surface protection of a hull shell, a pipeline, an offshore platform or an underwater structure.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The anti-corrosion, anti-fouling and drag-reducing composite coating provided by the present invention realizes the optimization of comprehensive performance through effective coupling of multiple functional layers; while each functional layer retains its original function, it realizes independent regulation through fine segmentation, and uses the characteristics of charged polymers and coupling agent small molecules to establish a strong interfacial bonding force between the substrate and each functional layer, thereby realizing integrity; at the same time, the preparation method adopted by the present invention has the advantages of wide application range and large-area coating. Description of the Drawings

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0015] Figure 1 It is a schematic structural diagram of an anti-corrosion, anti-fouling and drag-reducing composite coating in a typical implementation scheme of the present invention.

[0016] Explanation of reference numerals: 1 - substrate, 2 - base layer, 3 - corrosion barrier layer, 4 - connection layer, 5 - flexible anti-fouling layer. Detailed implementation manners

[0017] In view of the deficiencies of the prior art, the inventors of this case have proposed the technical solutions of the present invention through long-term research and a large number of practices. The following will clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] Specifically, as an aspect of the technical solution of the present invention, an anti-corrosion, anti-fouling and drag-reducing composite coating it involves includes: a base layer, a corrosion barrier layer, a connection layer and a flexible anti-fouling layer formed in sequence on the surface of the substrate;

[0019] Among them, the base layer includes an adhesive resin, a positively charged polymer, a filler and a diluent; the corrosion barrier layer includes a flexible polymer resin, a negatively charged polymer and two-dimensional nanosheets; the connection layer includes an adhesive resin, a positively charged polymer, a filler and a coupling agent; the flexible anti-fouling layer includes a flexible polymer resin and temperature-responsive polymer microcapsules encapsulating an anti-fouling agent; the positively charged polymer includes any one or a combination of two or more of polyvinylamine, polyaniline, poly(methacryloyloxyethyltrimethylammonium chloride), and polyacrylamide; the negatively charged polymer includes any one or a combination of two or more of polyglutamic acid, polyvinyl alcohol acid, and sodium polystyrenesulfonate.

[0020] Specifically, in the present invention, through the compounding of multiple functional layers, while retaining each function, each functional factor is segmented and independently regulated. Through the charged polymer and the linker small molecule, a strong interfacial binding force is generated between the substrate and each functional layer, unifying each functional layer into an integral structural layer. Among them, the base layer mainly provides the interfacial binding with the substrate, and a suitable material can be selected according to different substrates; the corrosion barrier layer mainly forms a dense barrier layer through the organic coordination of two-dimensional nanosheets and flexible polymers, reducing the diffusion of corrosive media; the connection layer has a strong interfacial binding between the corrosion barrier layer and the flexible layer, and also synergistically enhances the corrosion barrier property, further improving the corrosion resistance. The surface flexible layer has the ability to absorb and release deformation energy. When subjected to external forces, it can effectively absorb and release energy, thereby reducing the fluid resistance. It helps to reduce the friction of the coating in the fluid environment and improve its efficiency.

[0021] In some preferred embodiments, the thickness of the base layer is 20 - 60 μm.

[0022] In some preferred embodiments, the thickness of the corrosion barrier layer is 0.3 - 0.5 mm.

[0023] In some preferred embodiments, the thickness of the connection layer is 20 - 60 μm.

[0024] In some preferred embodiments, the thickness of the flexible antifouling layer is 0.2 - 0.5 mm.

[0025] In some preferred embodiments, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent includes:

[0026] Mixing an aqueous solution dispersed with nucleating particles with an oil-phase solution containing a temperature-responsive polymer monomer, a crosslinking agent, and an initiator, and carrying out emulsion polymerization at 50 - 80 °C for 12 - 24 h, and obtaining microcapsules through centrifugation and drying;

[0027] And adding the microcapsules into a solution containing an antifouling agent and mixing well, and obtaining the temperature-responsive polymer microcapsules encapsulated with an antifouling agent through stirring, centrifugation, and drying treatments.

[0028] Further, the temperature-responsive polymer monomer includes N-isopropylacrylamide and / or a block polymer containing N-isopropylacrylamide, and is not limited thereto.

[0029] Further, the antifouling agent includes any one or a combination of two or more of copper pyrithione, zinc pyrithione, and chitosan, and is not limited thereto.

[0030] Further, the crosslinking agent includes any one or a combination of two or more of N,N'-methylenebisacrylamide (MBA), divinylbenzene, and diisocyanate, and is not limited thereto.

[0031] Further, the initiator includes any one or a combination of two or more of potassium persulfate (KPS), azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (AIBME), and azodiisovaleronitrile, and is not limited thereto.

[0032] Further, the nucleating particles include any one or a combination of two or more of gas-phase hydrophobic SiO 2 , gas-phase hydrophilic SiO 2 , TiO 2 , Al 2 O 3 , and is not limited thereto.

[0033] Further, the volume ratio of the aqueous solution to the oil-phase solution is 1:4 to 1:2.

[0034] In some more specific embodiments, the structural schematic diagram of the anti-corrosion, anti-fouling and drag-reducing composite coating is as Figure 1 shown, including a substrate 1, a base layer 2, a corrosion barrier layer 3, a connection layer 4, and a flexible anti-fouling layer 5.

[0035] The anti-corrosion, anti-fouling and drag-reducing composite coating provided by the present invention is a multi-layer anti-corrosion and drag-reducing integrated coating, wherein the base layer can improve the adhesion between the coating and the substrate; the corrosion barrier layer can provide corrosion barrier and improve the corrosion protection performance of the coating; the presence of the connection layer can improve the adhesion performance of the flexible anti-fouling layer; the flexible anti-fouling layer provides anti-fouling and drag-reducing performance; at the same time, the preparation method adopted by the present invention has the advantages of wide application range and large-area coating.

[0036] Another aspect of the embodiments of the present invention also provides a preparation method of the foregoing anti-corrosion, anti-fouling and drag-reducing composite coating, which includes:

[0037] Applying a first base liquid containing at least an adhesive resin, a positively charged polymer, a filler, and a diluent to the surface of the substrate and performing a first curing treatment to form a base layer with a multi-level micro-nano structure;

[0038] Applying a second base liquid containing at least a polymer resin, a negatively charged polymer, two-dimensional nanosheets, and a diluent to the surface of the base layer and performing a second curing treatment to form a corrosion barrier layer;

[0039] Applying a third base liquid containing at least an adhesive resin, a positively charged polymer, a filler, a coupling agent, and a diluent to the surface of the corrosion barrier layer and performing a third curing treatment to form a connection layer;

[0040] Further, a fourth base liquid containing at least a flexible polymer resin, temperature-responsive polymer microcapsules encapsulating an antifouling agent, and a solvent is applied to the surface of the connection layer and subjected to a fourth curing treatment to form a flexible antifouling layer, thereby obtaining an anti-corrosion, anti-fouling, and drag-reducing composite coating.

[0041] In some preferred embodiments, the preparation method specifically includes: applying the first base liquid to the surface of the substrate by spraying or brushing and curing at room temperature for 12 to 24 h to form a base layer having a multi-level micro-nano structure. In the present invention, a multi-level structure is prepared by using mixed-scale fillers.

[0042] In some preferred embodiments, the preparation method specifically includes: applying the second base liquid to the surface of the base layer by spraying or brushing and curing at room temperature for 4 to 12 h to form a corrosion barrier layer.

[0043] In some preferred embodiments, the preparation method specifically includes: applying the third base liquid to the surface of the corrosion barrier layer by spraying or brushing and curing at room temperature for 12 to 24 h to form a connection layer.

[0044] In some preferred embodiments, the preparation method specifically includes: applying the fourth base liquid to the surface of the connection layer by spraying or brushing and curing at room temperature for 12 to 24 h to form a flexible antifouling layer.

[0045] In some preferred embodiments, the mass ratio of the adhesive resin, positively charged polymer, filler, and diluent in the first base liquid is 20 to 50: 0.5 to 5: 0.5 to 5: 0 to 30.

[0046] In some preferred embodiments, the mass ratio of the flexible polymer resin, negatively charged polymer, two-dimensional nanosheet, and diluent in the second base liquid is 20 to 50: 0.5 - 5: 0.5 - 5: 0 to 30.

[0047] In some preferred embodiments, the mass ratio of the adhesive resin, positively charged polymer, filler, coupling agent, and diluent in the third base liquid is 10 to 50: 0.5 to 5: 0.5 to 5: 0.5 to 5: 0 to 30.

[0048] In some preferred embodiments, the mass ratio of the flexible polymer resin, temperature-responsive polymer microcapsules encapsulating an antifouling agent, and solvent in the fourth base liquid is 30 to 50: 1 to 5: 0 to 30.

[0049] In some preferred embodiments, the adhesive resin includes any one or a combination of two or more of modified epoxy resin, epoxy zinc-rich primer, acrylic polyurethane paint, amino organosilicon resin, and polyurethane-modified epoxy resin, and is not limited thereto.

[0050] In some preferred embodiments, the filler includes any one or a combination of two or more of kaolin, talc powder, mica powder, zinc oxide, titanium dioxide, silica, glass microspheres, and diatomaceous earth, and is not limited thereto.

[0051] In some preferred embodiments, the particle size of the filler is 0.01 - 20 μm.

[0052] In some preferred embodiments, the filler includes micron-sized filler and nano-sized filler.

[0053] In some preferred embodiments, the diluent includes any one or a combination of two or more of toluene, xylene, ethanol, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, and formamide, and is not limited thereto.

[0054] In some preferred embodiments, the polymer resin includes any one or a combination of two or more of epoxy resin, phenolic epoxy resin, polyurethane formate, methyl methacrylate resin, and acrylic resin, and is not limited thereto.

[0055] In some preferred embodiments, the two-dimensional nanosheets include any one or a combination of two or more of BN, graphene, graphene oxide, MXene, and tungsten disulfide, and is not limited thereto.

[0056] In some preferred embodiments, the sheet diameter of the two-dimensional nanosheets is 1 - 30 μm.

[0057] In some preferred embodiments, the coupling agent includes any one or a combination of two or more of isocyanatopropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, diethylenetriaminepropyltrimethoxysilane, and vinyltriethoxysilane, and is not limited thereto.

[0058] In some preferred embodiments, the flexible polymer resin includes any one or a combination of two or more of silicone resin, polyurethane, acrylic-modified silicone resin, and polyurea, and is not limited thereto.

[0059] In some preferred embodiments, the solvent includes any one or a combination of two or more of toluene, xylene, ethyl acetate, acetone, ethanol, butanol, and butyl acetate, and is not limited thereto.

[0060] In some preferred embodiments, the substrate includes any one or a combination of two or more of steel substrate, aluminum alloy substrate, and copper alloy substrate, and is not limited thereto.

[0061] Another aspect of the embodiments of the present invention also provides the application of the aforementioned anti-corrosion, anti-fouling and drag-reducing composite coating in the surface protection of hull shells, pipelines, offshore platforms or underwater structures.

[0062] In the present invention, the base layer selects appropriate materials according to the characteristics of different substrates to enhance the stable interfacial bonding between the coating and the substrate; while the corrosion barrier layer realizes a strong barrier effect on corrosion factors through the organic combination of resin and two-dimensional sheet materials. In addition, the connection layer and the flexible anti-fouling layer can further incorporate temperature-responsive anti-fouling microcapsules to enhance the corrosion protection performance of the coating; the presence of the connection layer can improve the adhesion performance of the flexible anti-fouling layer; the flexible anti-fouling layer is composed of a flexible material and temperature-responsive anti-fouling microcapsules. The introduction of this layer enables the coating to effectively absorb and release energy when facing deformation, thereby significantly reducing the resistance encountered by the fluid during movement. In addition, by incorporating temperature-responsive anti-fouling microcapsules, the coating can intelligently control the release of anti-fouling agents according to temperature changes, thereby enhancing the overall anti-fouling performance of the coating and achieving the effect of anti-fouling and drag reduction; at the same time, the preparation method adopted in the present invention has the advantages of wide application range and large-area coating.

[0063] The technical solutions of the present invention will be further described in detail below in conjunction with several preferred embodiments and the accompanying drawings. These embodiments are implemented on the premise of the technical solutions of the invention, and detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0064] In the following examples, the experimental materials used, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0065] Example 1

[0066] (1) 70 wt.% epoxy zinc-rich primer, 5 wt.% polyvinylamine, 2.5 wt.% talcum powder and 2.5 wt.% nano-SiO 2 were dissolved in butyl acetate and mixed evenly to obtain the first base liquid; the base liquid was brushed on the surface of the substrate and cured at room temperature for 8 h to form the base layer;

[0067] (2) 70 wt.% one-component high-elastic silicone resin, 5 wt.% polyvinyl acid, 5 wt.% nano-BN were dissolved in butyl acetate and mechanically stirred evenly to obtain the second base liquid; the base liquid was in-situ brushed on the surface of the above base layer and cured at room temperature for 12 h to form the corrosion barrier layer;

[0068] (3) Dissolve 60 wt.% silicone resin, 10 wt.% 3-(methacryloyloxy)propyltrimethoxysilane, 5 wt.% polyvinylamine, and 10 wt.% talc powder in butyl acetate, and mix them evenly by mechanical stirring to obtain the third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0069] (4) Dissolve 70 wt.% one-component high-elastic silicone resin and 10 wt.% temperature-responsive polymer microcapsules encapsulated with antifouling agents in xylene, and mix them evenly by mechanical stirring to obtain the fourth base liquid; brush the base liquid in situ on the surface of the above connection layer and cure it at room temperature for 12 h to obtain the anti-corrosion, anti-fouling and drag-reducing composite coating.

[0070] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with antifouling agents is as follows:

[0071] Disperse 1.5 g of gas-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to prepare an aqueous phase. Add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase. Then mix the two phases of water and oil at a volume ratio of 1 / 3, and stir and react at a high speed at 50 °C for 12 h, centrifuge, and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of 2-pyridinethiol copper at 40 g / L, mix well, stir for 12 h, then centrifuge and dry to obtain the temperature-responsive polymer microcapsules encapsulated with antifouling agents.

[0072] Example 2

[0073] (1) Dissolve 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 2.5 wt.% micron zinc oxide, and 2.5 wt.% nano zinc oxide in toluene to obtain the first base liquid; brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0074] (2) Dissolve 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrenesulfonate, and 5 wt.% lamellar graphene in toluene, and mix them evenly by mechanical stirring to obtain the second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0075] (3) Dissolve 60 wt.% silicone resin, 10 wt.% isocyanatopropyltriethoxysilane, 5 wt.% polyaniline, and 10 wt.% lamellar graphene in butyl acetate, and uniformly mix them by mechanical stirring to obtain a third base liquid; in-situ brush coat this base liquid on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0076] (4) Dissolve 70 wt.% one-component high-elastic polyurethane resin and 10 wt.% temperature-responsive polymer microcapsules encapsulating an antifouling agent in toluene, and uniformly mix them by mechanical stirring to obtain a fourth base liquid; in-situ brush coat this base liquid on the surface of the above connection layer and cure it at room temperature for 12 h to obtain an anti-corrosion, anti-fouling, and drag-reducing composite coating.

[0077] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulating an antifouling agent is as follows:

[0078] Disperse 1.5 g of gas-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to prepare an aqueous phase, add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase, then mix the two phases of water and oil at a volume ratio of 1 / 3, and carry out a high-speed stirring reaction at 50 °C for 12 h, centrifuge, and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of 2-pyridinethiol copper at 40 g / L, mix well, stir for 12 h, then centrifuge and dry to obtain temperature-responsive polymer microcapsules encapsulating an antifouling agent.

[0079] Example 3

[0080] (1) Dissolve 70 wt.% acrylic resin, 5 wt.% polyacrylamide, 2.5 wt.% micron-sized silica, and 2.5 wt.% nano-sized silica particles in toluene to obtain a first base liquid; brush coat this base liquid on the surface of the substrate and cure it at room temperature for 8 h to form a base layer;

[0081] (2) Dissolve 70 wt.% epoxy resin, 5 wt.% sodium polystyrenesulfonate, and 5 wt.% lamellar graphene in toluene, and uniformly mix them by mechanical stirring to obtain a second base liquid; in-situ brush coat this base liquid on the surface of the above base layer and cure it at room temperature for 6 h to form a corrosion barrier layer;

[0082] (3) Dissolve 60 wt.% acrylic polyurethane paint, 10 wt.% diethylenetriaminepropyltrimethoxysilane, 5 wt.% polyacrylamide, and 10 wt.% graphene oxide in butyl acetate, and stir evenly by mechanical stirring to obtain a third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0083] (4) Dissolve 70 wt.% one-component high-elastic polyurea resin and 10 wt.% temperature-responsive polymer microcapsules encapsulated with antifouling agents in toluene, and stir evenly by mechanical stirring to obtain a fourth base liquid; brush the base liquid in situ on the surface of the above connection layer and cure it at room temperature for 12 h to obtain an anti-corrosion, anti-fouling and drag-reducing composite coating.

[0084] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with antifouling agents is as follows:

[0085] Disperse 1.5 g of gas-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to prepare an aqueous phase. Add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase. Then mix the water and oil phases at a volume ratio of 1 / 3, and stir and react at a high speed at 50 °C for 12 h, centrifuge, and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of 2-pyridinethiol copper at 40 g / L and mix well. After stirring for 12 h, centrifuge and dry to obtain temperature-responsive polymer microcapsules encapsulated with antifouling agents.

[0086] Comparative Example 1 (compared with Example 2, lacking the base layer)

[0087] (1) Dissolve 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrenesulfonate, and 5 wt.% lamellar graphene in toluene, and stir evenly by mechanical stirring to obtain a second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0088] (2) Dissolve 60 wt.% silicone resin, 10 wt.% isocyanatopropyltriethoxysilane, 5 wt.% polyaniline, and 10 wt.% lamellar graphene in butyl acetate, and stir evenly by mechanical stirring to obtain a third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0089] (3) Dissolve 70 wt.% of a single-component highly elastic polyurethane resin and 10 wt.% of temperature-responsive polymer microcapsules encapsulated with an antifouling agent in toluene, and stir evenly by mechanical stirring to obtain a fourth base liquid; brush the base liquid in situ on the surface of the above-mentioned connection layer and cure it at room temperature for 12 h to obtain a composite coating.

[0090] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is as follows:

[0091] Disperse 1.5 g of gaseous hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to prepare an aqueous phase, add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase, then mix the water and oil phases at a volume ratio of 1 / 3, stir and react at 50 °C for 12 h, centrifuge, and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of 2-pyridinethiol copper at 40 g / L, mix well, stir for 12 h, then centrifuge and dry to obtain temperature-responsive polymer microcapsules encapsulated with an antifouling agent.

[0092] Performance characterization: The prepared composite coating has weak bonding with the substrate and is prone to peeling.

[0093] Comparative Example 2 (compared with Example 2, lacking a corrosion barrier layer)

[0094] (1) Dissolve 70 wt.% of methyl methacrylate, 5 wt.% of polyvinylamine, 2.5 wt.% of micron-sized zinc oxide, and 2.5 wt.% of nano-sized zinc oxide in toluene to obtain a first base liquid; brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0095] (2) Dissolve 60 wt.% of an organosilicon resin, 10 wt.% of isocyanatopropyltriethoxysilane, 5 wt.% of polyaniline, and 10 wt.% of lamellar graphene in butyl acetate, and stir evenly by mechanical stirring to obtain a third base liquid; brush the base liquid in situ on the surface of the base layer and cure it at room temperature for 8 h to form a connection layer;

[0096] (3) Dissolve 80 wt.% of a single-component highly elastic polyurethane resin and 10 wt.% of temperature-responsive polymer microcapsules encapsulated with an antifouling agent in toluene, and stir evenly by mechanical stirring to obtain a fourth base liquid; brush the base liquid in situ on the surface of the above-mentioned connection layer and cure it at room temperature for 12 h to obtain a composite coating.

[0097] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is as follows:

[0098] Disperse 1.5 g of gaseous-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to obtain an aqueous phase. Add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase. Then mix the aqueous and oil phases at a volume ratio of 1 / 3, and carry out a high-speed stirring reaction at 50 °C for 12 h, followed by centrifugation and drying to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of copper 2-pyridinethiol at 40 g / L, mix well, stir for 12 h, then centrifuge and dry to obtain the temperature-responsive polymer microcapsules encapsulated with an antifouling agent.

[0099] Performance characterization: The corrosion resistance of the prepared composite coating is poor.

[0100] Comparative Example 3 (compared with Example 2, lacking a connection layer)

[0101] (1) Dissolve 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 2.5 wt.% micron-sized zinc oxide, and 2.5 wt.% nano-sized zinc oxide in toluene to obtain a first base liquid; brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0102] (2) Dissolve 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrenesulfonate, and 5 wt.% lamellar graphene in toluene, and mix them evenly by mechanical stirring to obtain a second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0103] (3) Dissolve 70 wt.% of a one-component high-elastic polyurethane resin and 10 wt.% of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent in toluene, and mix them evenly by mechanical stirring to obtain a fourth base liquid; brush the base liquid in situ on the surface of the above corrosion barrier layer and cure it at room temperature for 12 h to obtain the anti-corrosion, anti-fouling, and drag-reducing composite coating.

[0104] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is as follows:

[0105] Disperse 1.5 g of gaseous-phase hydrophobic SiO 2The aqueous phase was prepared by dispersing particles (30 nm) in 100 ml of deionized water. An oil phase was prepared by adding 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene. Then, the aqueous and oil phases were mixed at a volume ratio of 1 / 3 and stirred at high speed at 50 °C for 12 h, followed by centrifugation and drying to obtain poly(N-isopropylacrylamide) microcapsule particles. 1 g of the above microcapsule particles was added to an ethanol solution of copper pyrithione at 40 g / L and mixed thoroughly. After stirring for 12 h, centrifugation and drying were carried out to obtain temperature-responsive polymer microcapsules encapsulated with antifouling agents.

[0106] Performance characterization: The flexible drag reduction layer of the prepared composite coating has a weak bond with the underlying material and is prone to peeling off.

[0107] Comparative Example 4 (compared with Example 2, lacking the flexible drag reduction layer)

[0108] (1) 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 2.5 wt.% micron-sized zinc oxide, and 2.5 wt.% nano-sized zinc oxide were dissolved in toluene to obtain the first base liquid; the base liquid was brush-coated on the surface of the substrate and cured at room temperature for 12 h to form a base layer;

[0109] (2) 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrenesulfonate, and 5 wt.% lamellar graphene were dissolved in toluene and mechanically stirred evenly to obtain the second base liquid; the base liquid was in-situ brush-coated on the surface of the above base layer and cured at room temperature for 12 h to form a corrosion barrier layer;

[0110] (3) 60 wt.% silicone resin, 10 wt.% isocyanatopropyltriethoxysilane, 5 wt.% polyaniline, and 10 wt.% lamellar graphene were dissolved in butyl acetate and mechanically stirred evenly to obtain the third base liquid; the base liquid was in-situ brush-coated on the above corrosion barrier layer and cured at room temperature for 8 h to form a composite coating.

[0111] Performance characterization: The prepared composite coating has no drag reduction effect.

[0112] Comparative Example 5 (compared with Example 2, lacking the temperature-responsive polymer microcapsules encapsulated with antifouling agents)

[0113] (1) 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 2.5 wt.% micron-sized zinc oxide, and 2.5 wt.% nano-sized zinc oxide were dissolved in toluene to obtain the first base liquid; the base liquid was brush-coated on the surface of the substrate and cured at room temperature for 12 h to form a base layer;

[0114] (2) Dissolve 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrene sulfonate, and 5 wt.% lamellar graphene in toluene, and stir evenly by mechanical stirring to obtain the second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0115] (3) Dissolve 60 wt.% silicone resin, 10% isocyanatopropyltriethoxysilane, 5 wt.% polyaniline, and 10 wt.% lamellar graphene in butyl acetate, and stir evenly by mechanical stirring to obtain the third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0116] (4) Dissolve 80 wt.% one-component high-elastic polyurethane resin in toluene, and stir evenly by mechanical stirring to obtain the fourth base liquid; brush the base liquid in situ on the surface of the above connection layer and cure it at room temperature for 12 h to obtain the anti-corrosion, anti-fouling and drag-reducing composite coating.

[0117] Performance characterization: The prepared composite coating has poor anti-fouling effect.

[0118] Comparative Example 6 (compared with Example 2, lacking two-dimensional nanosheets)

[0119] (1) Dissolve 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 2.5 wt.% micron zinc oxide, and 2.5 wt.% nano zinc oxide in toluene to obtain the first base liquid; brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0120] (2) Dissolve 70 wt.% phenolic epoxy resin and 5 wt.% sodium polystyrene sulfonate in toluene, and stir evenly by mechanical stirring to obtain the second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0121] (3) Dissolve 60 wt.% silicone resin, 10% isocyanatopropyltriethoxysilane, and 5 wt.% polyaniline in butyl acetate, and stir evenly by mechanical stirring to obtain the third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0122] (4) Dissolve 70 wt.% one-component high-elastic polyurethane resin and 10 wt.% temperature-responsive polymer microcapsules encapsulated with anti-fouling agents in toluene, and stir evenly by mechanical stirring to obtain the fourth base liquid; brush the base liquid in situ on the surface of the above connection layer and cure it at room temperature for 12 h to obtain the anti-corrosion, anti-fouling and drag-reducing composite coating.

[0123] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is as follows:

[0124] Disperse 1.5 g of gas-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to obtain an aqueous phase. Add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase. Then mix the aqueous and oil phases at a volume ratio of 1 / 3 and stir at a high speed at 50 °C for 12 h. Centrifuge and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of 2-pyridinethiol copper at 40 g / L, mix well, stir for 12 h, then centrifuge and dry to obtain the temperature-responsive polymer microcapsules encapsulated with an antifouling agent.

[0125] Performance characterization: The prepared composite coating has poor corrosion resistance.

[0126] Comparative example 7 (compared with Example 2, polyvinylamine is missing in the base layer and sodium polystyrene sulfonate is missing in the corrosion barrier layer)

[0127] (1) Dissolve 70 wt.% methyl methacrylate, 2.5 wt.% micron zinc oxide, and 2.5 wt.% nano zinc oxide in toluene to obtain a first base liquid; brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0128] (2) Dissolve 70 wt.% phenolic epoxy resin and 5 wt.% lamellar graphene in toluene, and stir evenly by mechanical stirring to obtain a second base liquid; brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0129] (3) Dissolve 60 wt.% silicone resin, 10 wt.% isocyanatopropyltriethoxysilane, 5 wt.% polyaniline, and 10 wt.% lamellar graphene in butyl acetate, and stir evenly by mechanical stirring to obtain a third base liquid; brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connection layer;

[0130] (4) Dissolve 70 wt.% of a one-component high-elastic polyurethane resin and 10 wt.% of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent in toluene, and stir evenly by mechanical stirring to obtain a fourth base liquid; brush the base liquid in situ on the surface of the above connection layer and cure it at room temperature for 12 h to obtain the anti-corrosion, anti-fouling, and drag-reducing composite coating.

[0131] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is as follows:

[0132] Disperse 1.5 g of gaseous-phase hydrophobic SiO 2 particles (30 nm) in 100 ml of deionized water to obtain an aqueous phase. Add 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) to 50 ml of xylene to prepare an oil phase. Then mix the aqueous and oil phases at a volume ratio of 1 / 3 and stir vigorously at 50 °C for 12 h. Centrifuge and dry to obtain poly(N-isopropylacrylamide) microcapsule particles. Add 1 g of the above microcapsule particles to an ethanol solution of copper 2-pyridinethiolate at 40 g / L and mix well. After stirring for 12 h, centrifuge and dry to obtain temperature-responsive polymer microcapsules encapsulated with an antifouling agent.

[0133] Performance characterization: For the prepared composite coating, the bonding performance decreases:

[0134] Comparative Example 8 (compared with Example 2, the coupling agent isopropyltriethoxysilane is missing in the connecting layer)

[0135] (1) Dissolve 70 wt.% methyl methacrylate, 5 wt.% polyvinylamine, 5 wt.% micron-sized zinc oxide and nano-sized zinc oxide in toluene to obtain a first base liquid. Brush the base liquid on the surface of the substrate and cure it at room temperature for 12 h to form a base layer;

[0136] (2) Dissolve 70 wt.% phenolic epoxy resin, 5 wt.% sodium polystyrenesulfonate and 5 wt.% lamellar graphene in toluene and stir evenly by mechanical stirring to obtain a second base liquid. Brush the base liquid in situ on the surface of the above base layer and cure it at room temperature for 12 h to form a corrosion barrier layer;

[0137] (3) Dissolve 60 wt.% silicone resin, 5 wt.% polyaniline, 10 wt.% lamellar graphene in butyl acetate and stir evenly by mechanical stirring to obtain a third base liquid. Brush the base liquid in situ on the above corrosion barrier layer and cure it at room temperature for 8 h to form a connecting layer;

[0138] (4) Dissolve 70 wt.% of a one-component high-elastic polyurethane resin and 10 wt.% of temperature-responsive polymer microcapsules encapsulated with an antifouling agent in toluene and stir evenly by mechanical stirring to obtain a fourth base liquid. Brush the base liquid in situ on the surface of the above connecting layer and cure it at room temperature for 12 h to obtain an anticorrosive, antifouling and drag-reducing composite coating.

[0139] Among them, the preparation method of the temperature-responsive polymer microcapsules encapsulated with an antifouling agent is:

[0140] Disperse 1.5 g of gaseous-phase hydrophobic SiO2 The aqueous phase was prepared by dispersing particles (30 nm) in 100 ml of deionized water. The oil phase was prepared by adding 10 ml of N-isopropylacrylamide (NIPAM), 0.5 ml of N,N'-methylenebisacrylamide (MBA), and 0.2 ml of azobisisobutyronitrile (AIBN) into 50 ml of xylene. Then, the aqueous and oil phases were mixed at a volume ratio of 1 / 3 and stirred at a high speed at 50 °C for 12 h. After centrifugation and drying, poly(N-isopropylacrylamide) microcapsule particles were obtained. 1 g of the above microcapsule particles was added to an ethanol solution of copper pyrithione at 40 g / L and mixed thoroughly. After stirring for 12 h, centrifugation and drying were carried out to obtain temperature-responsive polymer microcapsules encapsulated with antifouling agents.

[0141] Performance characterization: For the prepared composite coatings, the bonding strength decreased. The performance tests were carried out on the composite coatings provided in the comparative examples and examples of the present invention. The adhesion test standard was GB / T5210-2006, and the salt spray test standard was GB / T10125-1997. The specific test results are shown in Table 1 below:

[0142] Table 1 Performance of the coatings prepared in Examples 1-3 and Comparative Examples 1-8

[0143] ;

[0144] In addition, the inventors of this case also referred to the foregoing examples and conducted tests with other raw materials, process operations, and process conditions described in this specification, and all obtained relatively ideal results.

[0145] It should be understood that the technical solutions of the present invention are not limited to the limitations of the above specific implementation cases. Any technical deformation made according to the technical solutions of the present invention without departing from the spirit and scope protected by the claims of the present invention falls within the protection scope of the present invention.

Claims

1. An anti-corrosion, anti-fouling and drag-reducing composite coating, characterized in that: include: A base layer, a corrosion barrier layer, a connecting layer and a flexible antifouling layer are sequentially formed on the surface of the substrate; Wherein, the base layer comprises an adhesive resin, a positively charged polymer, a filler and a diluent; the corrosion barrier layer comprises a flexible polymer resin, a negatively charged polymer and a two-dimensional nanosheet; the connecting layer comprises an adhesive resin, a positively charged polymer, a filler and a connecting agent; the flexible antifouling layer comprises a flexible polymer resin and a temperature-responsive polymer microcapsule encapsulating an antifouling agent; the positively charged polymer comprises any one or a combination of two or more of polyvinyl alcoholamine, polyaniline, polymethacryloyloxyethyl trimethyl ammonium chloride and polyacrylamide; the negatively charged polymer comprises any one or a combination of two or more of polyglutamic acid, polyvinyl alcohol acid and sodium polybenzene sulfonate; the adhesive resin comprises any one or a combination of two or more of modified epoxy resin, epoxy zinc-rich primer, acrylic polyurethane paint and amino silicone resin; the flexible polymer resin comprises any one or a combination of two or more of silicone resin, polyurethane, acrylic modified silicone resin and polyurea; The preparation method of the temperature-responsive polymer microcapsule encapsulating the antifouling agent comprises: The aqueous solution containing dispersed shaped core particles is mixed with an oily solution containing a temperature-responsive polymer monomer, a crosslinking agent, and an initiator, and emulsified polymerized at 50-80° C. for 12-24 hours, and then centrifuged and dried to obtain microcapsules; wherein the temperature-responsive polymer monomer includes N-isopropylacrylamide and / or a block polymer containing N-isopropylacrylamide; Furthermore, the microcapsules are added into a solution containing an antifouling agent and mixed thoroughly, and then stirred, centrifuged and dried to obtain temperature-responsive polymer microcapsules encapsulating the antifouling agent.

2. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The thickness of the base layer is 20-60 μm; and / or the thickness of the corrosion barrier layer is 0.3-0.5 mm; and / or the thickness of the connecting layer is 20-60 μm; and / or the thickness of the flexible antifouling layer is 0.2-0.5 mm.

3. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The antifouling agent includes any one of copper pyrithione, zinc pyrithione and chitosan or a combination of two or more thereof.

4. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The cross-linking agent includes any one or a combination of two or more of N,N'-methylenebisacrylamide, divinylbenzene and diisocyanate.

5. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The initiator includes any one of potassium persulfate, azobisisobutyronitrile, dimethyl azobisisobutyrate, and azobisisoheptanenitrile, or a combination of two or more thereof.

6. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The nucleation particles include any one of gas phase hydrophobic SiO2, gas phase hydrophilic SiO2, TiO2, and Al2O3, or a combination of two or more thereof.

7. The anti-corrosion, anti-fouling and drag-reducing composite coating according to claim 1, characterized in that: The volume ratio of the aqueous phase solution to the oil phase solution is 1:4-1:

2.

8. The method for preparing the anti-corrosion, anti-fouling and drag-reducing composite coating according to any one of claims 1 to 7, characterized in that: include: Applying a first base liquid containing at least an adhesive resin, a positively charged polymer, a filler, and a diluent to the surface of a substrate and subjecting the substrate to a first curing treatment to form a base layer having a multi-level micro-nano structure; Applying a second base liquid containing at least a polymer resin, a negatively charged polymer, two-dimensional nanosheets and a diluent to the surface of the base layer and performing a second curing treatment to form a corrosion barrier layer; Applying a third base liquid containing at least an adhesive resin, a positively charged polymer, a filler, a connector and a diluent to the surface of the corrosion barrier layer and performing a third curing treatment to form a connecting layer; And, a fourth base liquid containing at least a flexible polymer resin, a temperature-responsive polymer microcapsule encapsulating an antifouling agent and a solvent is applied to the surface of the connecting layer and subjected to a fourth curing treatment to form a flexible antifouling layer, thereby obtaining an anticorrosion, antifouling and drag-reducing composite coating.

9. The preparation method according to claim 8, characterized in that: The multi-level micro-nano structure includes a micron-level peak-valley structure and a nano-level structure covering the micron-level surface; the scale of the micron-level peak-valley structure is 20-100 μm, and the scale of the nano-level structure is 30-300 nm.

10. The preparation method according to claim 8, characterized in that: Specifically include: Applying the first base liquid to the surface of the substrate by spraying or brushing and curing it at room temperature for 12 to 24 hours to form a base layer with a multi-level micro-nano structure; and / or, applying the second base liquid to the surface of the base layer by spraying or brushing and curing it at room temperature for 4 to 12 hours to form a corrosion barrier layer; and / or, applying the third base liquid to the surface of the corrosion barrier layer by spraying or brushing and curing it at room temperature for 12 to 24 hours to form a connecting layer; And / or, the fourth base liquid is applied to the surface of the connecting layer by spraying or brushing and cured at room temperature for 12 to 24 hours to form a flexible antifouling layer.

11. The preparation method according to claim 8, characterized in that: The mass ratio of the adhesive resin, the positively charged polymer, the filler and the diluent in the first base liquid is 20-50: 0.5-5: 0.5-5: 0-30; And / or, the mass ratio of the flexible polymer resin, the negatively charged polymer, the two-dimensional nanosheets and the diluent in the second base liquid is 20-50: 0.5-5: 0.5-5: 0-30; And / or, the mass ratio of the adhesive resin, the positively charged polymer, the filler, the connector and the diluent in the third base liquid is 10-50: 0.5-5: 0.5-5: 0.5-5: 0-30; And / or, the mass ratio of the flexible polymer resin, the temperature-responsive polymer microcapsules encapsulating the antifouling agent, and the solvent in the fourth base liquid is 30-50:1-5:0-30.

12. The preparation method according to claim 8, characterized in that: The filler comprises any one or a combination of two or more of kaolin, talc, mica powder, zinc oxide, titanium dioxide, silicon dioxide, glass beads, and diatomaceous earth; and / or the particle size of the filler is 0.01-20 μm; and / or the filler comprises a micron-grade filler and a nano-grade filler.

13. The preparation method according to claim 8, characterized in that: The diluent includes any one of toluene, xylene, ethanol, ethyl acetate, butyl acetate, propylene glycol methyl ether, and formamide, or a combination of two or more thereof.

14. The preparation method according to claim 8, characterized in that: The polymer resin includes any one of epoxy resin, phenolic epoxy resin, polyurethane formate, methyl methacrylate resin, and acrylic resin, or a combination of two or more thereof.

15. The preparation method according to claim 8, characterized in that: The two-dimensional nanosheet includes any one of BN, graphene, graphene oxide, MXene, and tungsten disulfide, or a combination of two or more thereof; and / or the size of the two-dimensional nanosheet is 1 to 30 μm.

16. The preparation method according to claim 8, characterized in that: The linking agent includes any one of isocyanate propyl triethoxy silane, 3-(isobutyleneoxy)propyl trimethoxy silane, aminopropyl triethoxy silane, γ-glycidyloxypropyl trimethoxy silane, diethylene triaminopropyl trimethoxy silane, and vinyl triethoxy silane, or a combination of two or more thereof.

17. The preparation method according to claim 8, characterized in that: The solvent includes any one of toluene, xylene, ethyl acetate, acetone, ethanol, butanol, and butyl acetate, or a combination of two or more thereof.

18. The preparation method according to claim 8, characterized in that: The substrate includes any one of a steel substrate, an aluminum alloy substrate, and a copper alloy substrate, or a combination of two or more thereof.

19. Use of the anti-corrosion, anti-fouling and drag-reducing composite coating according to any one of claims 1 to 7 in the surface protection of pipelines, offshore platforms or underwater structures.

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