A deep-sea pressure-resistant wear-resistant anticorrosive coating, a preparation method and application thereof

Abstract

The application provides a deep-sea pressure-resistant wear-resistant anticorrosive coating as well as a preparation method and application thereof, wherein, compared with the prior art, the deep-sea pressure-resistant wear-resistant anticorrosive coating is prepared by taking magnolol-based tetrafunctional epoxy resin as a main film-forming material, modifying graphite carbon nitride by using sulfonated polyaniline, obtaining sulfonated polyaniline modified graphite carbon nitride, and adding the sulfonated polyaniline modified graphite carbon nitride into the epoxy resin as a functional wear-resistant anticorrosive filler. The chemical grafting of the sulfonated polyaniline on the surface of the graphite carbon nitride increases the roughness of the surface of the graphite carbon nitride, meanwhile, the sulfonated polyaniline modified graphite carbon nitride has good compatibility with the magnolol-based tetrafunctional epoxy resin, the compactness and toughness of the coating are improved, and then the anti-erosion performance of the composite coating is improved. The coating provided by the application has a salt fog resistance of greater than or equal to 4000h, a wear resistance of less than or equal to 30mg (GB / T 1768, 1000g / 500r), and a deep-sea 6000m seawater pressure resistance of greater than or equal to 60d.

Description

Technical Field

[0001] This invention belongs to the field of coatings and metal protection technology, specifically relating to a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating, its preparation method, and its application. Background Technology

[0002] With the development and utilization of marine resources, marine engineering equipment has been widely used in marine engineering. However, when marine steel structures are in service in harsh marine environments, they are subjected to electrochemical corrosion and erosion wear due to seawater erosion, oxygen and solid particles in the splash zone. After being impacted, marine steel structures will deform and break, making it easier for corrosive media to erode the metal substrate. Therefore, in order to improve the service life of marine equipment, protective coatings are usually applied for protection. The protective coating should have the following characteristics in resisting erosion and corrosion: (1) strong adhesion, strong adhesion between the coating and the substrate can ensure that the coating will not fall off or fail during erosion; (2) friction and wear resistance, the coating will generate friction and wear during the impact of seawater, so the coating has excellent friction and wear resistance, which can greatly improve the protective effect of the coating; (3) excellent barrier performance, seawater and silt will carry a large amount of corrosive media during the impact of the coating, and the coating has excellent barrier performance, which can effectively inhibit the penetration of corrosive media into the coating and improve the protective effect on the substrate.

[0003] Epoxy resin is the preferred film-forming material for erosion-resistant coatings in marine environments. This is mainly because the epoxy resin molecule contains active epoxy groups, which can undergo cross-linking reactions with various types of curing agents to form a multi-dimensional network polymer. Epoxy coatings have the following advantages: ① Strong adhesion, exhibiting excellent bonding to various substrates, and low curing shrinkage; ② Excellent chemical resistance, especially outstanding alkali resistance; ③ Good compatibility, being miscible with various resins and additives, and good dispersibility of fillers in epoxy resin; ④ The resulting coating film is hard and possesses a certain degree of toughness, and the relatively low molecular weight of epoxy resin facilitates the formulation of solvent-free coatings. However, pure epoxy coatings suffer from high cross-linking density, resulting in high brittleness and poor impact and friction wear resistance. Adding functional fillers is the most direct and effective method to improve the impact and friction wear resistance of epoxy coatings.

[0004] Graphite carbon nitride (g-C3N4) is a covalent compound with a hardness comparable to diamond. It is easy to manufacture, wear-resistant, non-toxic, and possesses strong physicochemical stability. As a two-dimensional material with excellent electron transport properties, g-C3N4 shows great potential in corrosion protection. However, g-C3N4 also has its drawbacks, such as a small specific surface area and a tendency to agglomerate. Summary of the Invention

[0005] The purpose of this invention is to provide a deep-sea pressure-resistant, wear-resistant, and anti-corrosion coating and its preparation method. This invention modifies graphite carbon nitride (g-C3N4) with sulfonated polyaniline (SPANi) to obtain sulfonated polyaniline-modified graphite carbon nitride g-C3N4@SPANi, which is then added as a functional wear-resistant and anti-corrosion filler to epoxy resin to prepare the deep-sea pressure-resistant, wear-resistant, and anti-corrosion coating. In addition, the magnolol-based tetrafunctional epoxy resin prepared by the deacidification reaction of magnolol and epichlorohydrin contains many epoxy groups. After reacting with the polyetheramine curing agent, it can form a three-dimensional cross-linked structure, improving the density of the paint film. After curing, the paint film has strong adhesion, good resistance to deep-sea high pressure, and high hardness. The deep-sea pressure-resistant, wear-resistant, and anti-corrosion coating provided by this invention has a salt spray resistance ≥4000h, a wear resistance ≤30mg (GB / T 1768, 1000g / 500r), and can withstand seawater pressure at a depth of 6000 meters for ≥60 days.

[0006] Another objective of this invention is to provide an application of a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating for use in deep-sea engineering construction, thereby improving long-term erosion resistance and corrosion resistance.

[0007] The specific technical solution of this invention is as follows:

[0008] The present invention provides a deep-sea pressure-resistant, wear-resistant and corrosion-resistant coating, the raw materials of which include sulfonated polyaniline modified graphite carbon nitride;

[0009] The preparation method of the sulfonated polyaniline modified graphite carbon nitride is as follows:

[0010] After aniline, o-aminobenzenesulfonic acid and graphite carbon nitride are mixed evenly, hydrochloric acid solution is added under ice bath conditions, and after stirring, a catalyst is added to react and obtain sulfonated polyaniline modified graphite carbon nitride.

[0011] In the preparation method of sulfonated polyaniline modified graphite carbon nitride, the mass ratio of aniline, o-aminobenzenesulfonic acid, and graphite carbon nitride is 1-2:1-2:2-3; the ratio of the total mass of aniline, o-aminobenzenesulfonic acid, and graphite carbon nitride to the volume of hydrochloric acid solution is 2-3:1 g / mL, and the solubility of hydrochloric acid solution is 1-1.5 mol / L; the stirring time is 30-60 min; the reaction time is 30-50 h under ice bath conditions at 0-5℃; the amount of catalyst is 0.5 / 100-1 / 100 of the total mass of aniline, o-aminobenzenesulfonic acid, and graphite carbon nitride; the catalyst is ammonium persulfate; after the reaction is completed, the mixture is washed with deionized water and vacuum filtered to obtain sulfonated polyaniline modified graphite carbon nitride.

[0012] The raw materials of the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating also include modified epoxy resin;

[0013] The modified epoxy resin is a magnolol tetrafunctional epoxy resin.

[0014] The modified epoxy resin is prepared by:

[0015] Honokiol and epichlorohydrin were mixed evenly, a catalyst was added, and a strong alkaline solution was added dropwise under heating conditions with stirring. The mixture was then vacuum filtered to obtain honokiol-based difunctional epoxy. Honokiol-based difunctional epoxy was added dropwise to m-chloroperoxybenzoic acid, reacted at room temperature, and then heated to react again. The mixture was filtered and washed with an alkaline solution to obtain the target product, honokiol-based tetrafunctional epoxy resin.

[0016] In the preparation method of the modified epoxy resin, the mass ratio of magnolol to epichlorohydrin is 1:8 to 2:8, the amount of catalyst added is 1 / 1000 to 5 / 1000 of the total mass of magnolol and epichlorohydrin, and the catalyst is tributylamine; the mass of the strong alkali solution is 25%-35% of the total mass of magnolol and epichlorohydrin; the strong alkali solution is a 50wt% sodium hydroxide solution or potassium hydroxide solution; the heating conditions refer to a temperature of 80-85℃; the stirring reaction refers to a temperature of 80-85℃. The reaction time is 24–48 h at room temperature; after the reaction is completed by stirring, the product is washed 8–10 times with deionized water and then rotary evaporated for 3–5 h under vacuum water pump at 60–80 °C to obtain magnolol difunctional epoxy; the mass ratio of magnolol difunctional epoxy to m-chloroperoxybenzoic acid is 1:1 to 1:1.5; the room temperature reaction time is 48–96 h at 25 °C; the heating reaction refers to heating to 50 °C and then reacting for 4–5 h; the washing with alkaline solution refers to washing 8–10 times with a low concentration of 0.1 mol / L KOH solution.

[0017] Preferably, the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating provided by the present invention comprises the following raw materials in parts by weight: 28-33 parts modified epoxy resin, 30-50 parts sulfonated polyaniline modified graphite carbon nitride, 10-20 parts reactive diluent, 2-3 parts silane coupling agent, 15-20 parts polyetheramine curing agent, 15-30 parts filler, and 1.5-2.5 parts additives.

[0018] The active diluent is one or a combination of octyl glycidyl ether, phenyl glycidyl ether, and neopentyl glycol diglycidyl ether.

[0019] The silane coupling agent is one or a combination of KH550, KH560 and KH570.

[0020] The polyetheramine curing agent was purchased from Shanghai Aladdin Company, brand name D230, and was of analytical grade.

[0021] The filler is one or a combination of aluminum polyphosphate, iron oxide red, and graphene, wherein the aluminum polyphosphate is aluminum tripolyphosphate.

[0022] The additive is one or a combination of several of the following: anti-settling agent fumed silica, dispersant EFKA4010, and leveling agent BYK333.

[0023] This invention provides a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating for metal substrates. The coating uses magnolol-based tetrafunctional epoxy resin as the main film-forming material, sulfonated polyaniline-modified graphite carbon nitride as a wear-resistant and corrosion-resistant filler, and polyetheramine as an epoxy curing agent. The coating increases the surface roughness of graphite carbon nitride through chemical grafting of sulfonated polyaniline onto the surface. Simultaneously, the good compatibility between sulfonated polyaniline-modified graphite carbon nitride and epoxy resin improves the density and toughness of the coating, thereby enhancing the erosion resistance of the composite coating.

[0024] The present invention provides a method for preparing a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating, specifically comprising:

[0025] Sulfonated polyaniline-modified graphite carbon nitride, reactive diluent, and filler are added to the modified epoxy resin and stirred to disperse. Then, additives and silane coupling agents are added and stirred. Finally, polyetheramine curing agent is added and stirred evenly to obtain a deep-sea pressure-resistant, wear-resistant, and anti-corrosion coating.

[0026] The stirring and dispersing refers to dispersing at 500-800 r / min for 10-15 min;

[0027] The stirring refers to stirring at 2000 r / min for 30 minutes.

[0028] This invention provides an application of a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating for deep-sea engineering construction. The specific application method is as follows:

[0029] Deep-sea pressure-resistant, wear-resistant, and anti-corrosion coatings are sprayed or coated onto the metal substrates of marine engineering equipment, with a film thickness of 100-500μm, for use in deep-sea engineering construction, to achieve long-term anti-corrosion and anti-erosion functions for the substrate.

[0030] Compared with existing technologies, the magnolol-based tetrafunctional epoxy resin prepared by the deacidification reaction of magnolol and epichlorohydrin in this invention contains a large number of epoxy groups. After reacting with polyetheramine curing agent, it can form a three-dimensional cross-linked structure, improving the density of the paint film. The cured paint film has strong adhesion, good resistance to deep-sea high pressure, and high hardness. Self-made sulfonated polyaniline-modified graphite carbon nitride is used as a wear-resistant and corrosion-resistant filler. Sulfonated polyaniline can effectively inhibit the agglomeration of graphite carbon nitride. This wear-resistant and corrosion-resistant filler has high hardness and good wear resistance. After chemical grafting of sulfonated polyaniline onto the surface of graphite carbon nitride, it can increase the roughness of graphite carbon nitride and improve its compatibility with epoxy resin, thereby improving the erosion resistance and wear resistance of the composite coating. This invention uses glycidyl ether as the reactive diluent for the coating. During the paint film curing process, there is no solvent evaporation, low VOC emissions, and it is safe and environmentally friendly. Meanwhile, the deep-sea erosion-resistant coating prepared by this invention has a salt spray resistance of ≥4000h, an abrasion resistance of ≤30mg (GB / T1768, 1000g / 500r), and can withstand seawater pressure at a depth of 6000 meters for ≥60d. Attached Figure Description

[0031] Figure 1 A schematic diagram illustrating the preparation of magnolol tetrafunctional epoxy resin;

[0032] Figure 2 Schematic diagram of the preparation of sulfonated polyaniline modified graphite carbon nitride composite epoxy coating: (a) shows the preparation process of sulfonated polyaniline modified graphite carbon nitride, and (b) shows the polymerization reaction to generate sulfonated polyaniline; in the figure, m:n = 1:1~2;

[0033] Figure 3 Electron transmission electron microscopy (TEM) image of sulfonated polyaniline-modified graphitic carbon nitride prepared in Example 1;

[0034] Figure 4 Infrared spectra of sulfonated polyaniline-modified graphite carbon nitride, polyaniline, and graphite carbon nitride prepared for Example 1;

[0035] Figure 5 Photograph of the coating after 4000 hours of neutral salt spray test following the application of the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating prepared in Example 2 onto a carbon steel surface.

[0036] Figure 6 These are photos of the on-site construction and finished product of the deep-sea pressure-resistant, wear-resistant and corrosion-resistant coating prepared in Example 2, applied to offshore wind turbine steel pipe piles and cages. The coating thickness is 500 micrometers. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0039] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0040] Example 1

[0041] A method for preparing a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating includes the following steps:

[0042] 1) Preparation of magnolol tetrafunctional epoxy resin:

[0043] 10.0 g of magnolol and 80.0 g of epichlorohydrin were mixed thoroughly in a three-necked flask, with 0.09 g of tributylamine added as a catalyst. The water bath temperature was maintained at 80 °C, and then 28.0 g of 50 wt% NaOH solution was added dropwise. The mixture was stirred at 200 r / min for 24 h, washed 10 times with deionized water, and rotary evaporated under vacuum at 60 °C for 5 h to obtain magnolol-based difunctional epoxy resin. 100.0 g of m-chloroperoxybenzoic acid was added dropwise to 80 g of magnolol-based difunctional epoxy resin, and the reaction was maintained at room temperature for 48 h. The temperature was then raised to 50 °C and reacted for another 5 h. The mixture was filtered, washed 10 times with 0.1 mol / L KOH solution to obtain the target product, magnolol-based tetrafunctional epoxy resin. A schematic diagram of the preparation is shown below. Figure 1 .

[0044] 2) Preparation of sulfonated polyaniline-modified graphite carbon nitride:

[0045] First, 15.1 g of aniline, 16.5 g of o-aminobenzenesulfonic acid, and 21.6 g of graphitic carbon nitride were mixed thoroughly in a three-necked flask. Then, 25 mL of 1 mol / L hydrochloric acid solution was added in an ice bath, and the mixture was slowly stirred for 60 min. Next, 0.28 g of ammonium persulfate catalyst was added, and the reaction continued for 48 h. The mixture was then washed five times with deionized water and filtered under vacuum to obtain sulfonated polyaniline-modified graphitic carbon nitride. A schematic diagram of the preparation process is shown below. Figure 2 ; Figure 3Electron transmission electron microscopy (TEM) images of sulfonated polyaniline-modified graphite carbon nitride were prepared. As shown in the images, the graphite carbon nitride exhibits a two-dimensional layered structure with a sheet diameter and length of approximately 1–2 μm, and is uniformly dispersed, indicating that sulfonated polyaniline can effectively inhibit the aggregation of graphite carbon nitride.

[0046] Figure 4 Infrared spectra of sulfonated polyaniline-modified graphitic carbon nitride, commercially available polyaniline, and graphitic carbon nitride prepared for Example 1 are shown. For pure graphitic carbon nitride (g-C3N4), the infrared spectrum is 1244 cm⁻¹. -1 It is the CN stretching vibration absorption peak, 812 cm⁻¹ -1 It is the absorption peak of the in-plane bending vibration of CH, at 1476 cm⁻¹. -1 It is the absorption peak of NH tensile vibration; for pure polyaniline (PANi), it is 1244 cm⁻¹. -1 and 1476cm -1 The location is attributed to the stretching vibration of the CN bond and the tensile vibration of the NH bond, 3467 cm. -1 The peak value at 616 cm⁻¹ is due to the OH stretching vibration. For sulfonated polyaniline-modified graphitic carbon nitride (g-C₃N₄@SPANi), a new characteristic peak appears, with a peak value at 616 cm⁻¹. -1 1146cm -1 and 1303cm -1 The values ​​correspond to the CS, SO, and S=O tensile vibrations, respectively, indicating that the sulfonic acid groups have been successfully grafted onto the polyaniline chain and adsorbed on the surface of graphitic carbon nitride.

[0047] 3) Preparation of deep-sea pressure-resistant, wear-resistant and corrosion-resistant coatings

[0048] Add 30g of wear-resistant and corrosion-resistant filler sulfonated polyaniline modified graphite carbon nitride, 6g of octyl glycidyl ether, and 4g of phenyl glycidyl ether to 30g of magnolol tetrafunctional epoxy resin in sequence, and stir at 500r / min until homogeneous. Then add 25g of aluminum tripolyphosphate and 1g of graphene powder, and disperse at 800r / min for 15min. Continue to add 0.5g of anti-settling agent fumed silica, 1.5g of dispersant EFKA4010, and 2.5g of silane coupling agent KH560, and stir at 2000r / min for 30min. Grind to a fineness of 50μm. Finally, add 18g of polyetheramine curing agent (purchased from Shanghai Aladdin Company, brand name D230, analytical grade), and stir until homogeneous to obtain deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating.

[0049] Basic performance characterization of the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating prepared above:

[0050] Deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating was sprayed onto a carbon steel plate (substrate sandblasted to Sa2.5 grade) using compressed air and cured at room temperature (25℃) for 24 hours, with the film thickness controlled at 100±5μm, thus obtaining an anti-erosion coating. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea seawater pressure at 6000 meters, salt spray performance, and wear resistance of the coating prepared in Example 1 are shown in Table 1.

[0051] Example 2

[0052] A method for preparing a deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating includes the following steps:

[0053] The preparation of this coating is basically the same as in Example 1, except that 40g of sulfonated polyaniline-modified graphite carbon nitride and 15g of aluminum tripolyphosphate are added during the preparation of the coating, while other parameters remain unchanged. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea water pressure at 6000 meters, salt spray performance, and abrasion resistance of the coating prepared in Example 2 are shown in Table 1.

[0054] Figure 5 The image shows the coating after 4000 hours of neutral salt spray testing following application of the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating prepared in Example 2 onto a carbon steel surface. After 4000 hours of salt spray testing, the coating prepared in Example 2 showed no corrosion, peeling, or blistering, and the paint film exhibited good adhesion to the carbon steel substrate, indicating that the self-made coating has excellent anti-corrosion performance on the carbon steel substrate.

[0055] Figure 6 These are photos of the on-site construction and finished products of the deep-sea pressure-resistant, wear-resistant and corrosion-resistant coating prepared in Example 2, applied to offshore wind power steel pipe piles and cages. The coating has good construction performance, and after curing, the adhesion of the paint film on the steel pipe pile substrate reached 15.8 MPa.

[0056] Comparative Example 1

[0057] The method described in Example 1 was followed, except that the 30g of magnolol tetrafunctional epoxy resin prepared in Example 1 was replaced with commercially available epoxy resin E51 (purchased from Shandong Deyuan Epoxy Technology Co., Ltd.), while all other parameters remained unchanged. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea water pressure at 6000 meters, salt spray performance, and abrasion resistance of the coating in Comparative Example 1 are shown in Table 1.

[0058] Comparative Example 2

[0059] The method described in Example 1 was followed, except that the wear-resistant and corrosion-resistant filler sulfonated polyaniline modified graphite carbon nitride was not added, and the amount of aluminum tripolyphosphate added was increased to 55g, while other parameters remained unchanged. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea water pressure at 6000 meters, salt spray performance, and wear resistance of the coating prepared in Comparative Example 2 are shown in Table 1.

[0060] Comparative Example 3

[0061] The method described in Example 1 was followed, except that the wear-resistant and corrosion-resistant filler sulfonated polyaniline modified graphite carbon nitride was not added, and 30g of commercially available graphite carbon nitride was added, while other parameters remained unchanged. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea water pressure at 6000 meters, salt spray performance, and wear resistance of the coating prepared in Comparative Example 3 are shown in Table 1.

[0062] Comparative Example 4

[0063] The method described in Example 1 was followed, except that the wear-resistant and corrosion-resistant filler sulfonated polyaniline modified graphite carbon nitride was not added, nor was the magnolol tetrafunctional epoxy resin prepared in Example 1; instead, 30g of commercially available graphite carbon nitride and 30g of commercially available epoxy resin E51 (purchased from Shandong Deyuan Epoxy Technology Co., Ltd.) were added, while other parameters remained unchanged. The adhesion, hardness, impact resistance, erosion resistance, resistance to simulated deep-sea water pressure at 6000 meters, salt spray performance, and wear resistance of the coating prepared in Comparative Example 4 are shown in Table 1.

[0064] Table 1. Comprehensive physical properties of paint films applied to carbon steel surfaces in each embodiment and comparative example.

[0065]

[0066] Note 1: The simulated high-pressure seawater environment was achieved using the Cortest SSRT / Constantload / Low CycleFatigue testing system. The pressure was controlled at (60.0±0.1) MPa, the corrosive medium was 3.5wt% NaCl solution, and a circulating temperature control system was used to maintain the temperature inside the chamber at 4±1℃. Every 10 days, the coating sample was taken out to observe whether the paint film had failed or corroded. If the coating did not fail, the high-pressure test continued.

[0067] Note 2: Erosion resistance test method: The erosion resistance of the coating was tested using a solid / liquid / gas three-phase flow erosion abrasion tester. The eroding agent consisted of SiC particles and water in a mass ratio of 1:4 (where the SiC particles were spherical with a diameter of 100μm to 150μm). The jet velocity was 2.36m / s (gas pressure was 0.2MPa), the impact angle was 90°, and the erosion time of the coating sample was 30min. The mass difference before and after erosion was recorded.

[0068] Comparing the test results of Examples 1 and 2, it is shown that the content of sulfonated polyaniline-modified graphite carbon nitride is directly proportional to the abrasion resistance and erosion resistance of the coating film. Increasing the content of sulfonated polyaniline-modified graphite carbon nitride in the formulation components increases the hardness of the cured coating, thereby enhancing its abrasion resistance and erosion resistance.

[0069] Comparing the test results of Example 1 and Comparative Example 1, it is demonstrated that the self-made magnophenol-based tetrafunctional epoxy resin, as the main film-forming substance, can significantly improve the hardness, resistance to deep-sea seawater pressure corrosion, and salt spray resistance of the coating film on carbon steel. The main reason is that the magnophenol-based tetrafunctional epoxy resin contains many epoxy functional groups, which, after reacting with the polyetheramine curing agent, can form a three-dimensional cross-linked structure, improving the density and wear resistance of the coating film.

[0070] Comparing the test results of Example 1 and Comparative Example 2, it is shown that using sulfonated polyaniline modified graphite carbon nitride as a wear-resistant and corrosion-resistant filler can improve the hardness, wear resistance and erosion resistance of the paint film.

[0071] By comparing the test results of Example 1 and Comparative Example 3, it is shown that adding commercially available graphitic carbon nitride (without chemical modification) to epoxy resin leads to a decrease in the salt spray resistance, deep-sea pressure resistance, impact resistance, and erosion resistance of the coating film.

[0072] Comparative results from Examples 1, 3, and 4 demonstrate that the magnophenol-based tetrafunctional epoxy resin exhibits better salt spray resistance and adhesion than commercially available epoxy resin E51. Furthermore, the use of sulfonated polyaniline-modified graphite carbon nitride as a wear-resistant and corrosion-resistant filler results in a coating film with superior wear resistance and erosion resistance. Therefore, the combined use of magnophenol-based tetrafunctional epoxy resin and sulfonated polyaniline-modified graphite carbon nitride can synergistically enhance the coating film's erosion resistance and deep-sea pressure resistance.

[0073] In this invention, the high epoxy value of the magnolol-based tetrafunctional epoxy resin results in high crosslinking density and increased strength after reaction with the curing agent. When combined with sulfonated polyaniline-modified graphite carbon nitride, the overall erosion resistance and wear resistance of the coating are improved. Comparative experimental results from examples and comparative examples demonstrate the synergistic effect of the above raw materials.

[0074] The above description of the embodiments is intended to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating, characterized in that, The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating comprises the following raw materials in parts by weight: 28-33 parts modified epoxy resin, 30-50 parts sulfonated polyaniline modified graphite carbon nitride, 10-20 parts reactive diluent, 2-3 parts silane coupling agent, 15-20 parts polyetheramine curing agent, 15-30 parts filler, and 1.5-2.5 parts additives. The modified epoxy resin is a magnolol tetrafunctional epoxy resin. The preparation method of the sulfonated polyaniline modified graphite carbon nitride is as follows: After aniline, o-aminobenzenesulfonic acid and graphite carbon nitride are mixed evenly, hydrochloric acid solution is added under ice bath conditions, and after stirring, a catalyst is added to react and obtain sulfonated polyaniline modified graphite carbon nitride.

2. The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to claim 1, characterized in that, The mass ratio of aniline, o-aminobenzenesulfonic acid, and graphitic carbon nitride is 1~2:1~2:2~3; the amount of catalyst used is 0.5 / 100~1 / 100 of the total mass of aniline, o-aminobenzenesulfonic acid, and graphitic carbon nitride.

3. The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to claim 1 or 2, characterized in that, The stirring time is 30-60 minutes; the reaction time is 30-50 hours under ice bath conditions at 0-5°C.

4. The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to claim 1 or 2, characterized in that, The catalyst is ammonium persulfate.

5. The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to claim 4, characterized in that, The active diluent is one or a combination of octyl glycidyl ether, phenyl glycidyl ether, and neopentyl glycol diglycidyl ether.

6. The deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to claim 4 or 5, characterized in that, The polyetheramine curing agent is D230 polyetheramine curing agent.

7. A method for preparing the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to any one of claims 1-6, characterized in that, The preparation method is as follows: Sulfonated polyaniline-modified graphite carbon nitride, reactive diluent, and filler are added to the modified epoxy resin and stirred to disperse. Then, additives and silane coupling agents are added and stirred. Finally, polyetheramine curing agent is added and stirred evenly to obtain a deep-sea pressure-resistant, wear-resistant, and anti-corrosion coating.

8. The application of the deep-sea pressure-resistant, wear-resistant, and corrosion-resistant coating according to any one of claims 1-6, characterized in that, Used for deep-sea engineering construction.

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