Deep-sea pressure-resistant shell protective coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses a deep-sea pressure-resistant shell protective coating and a preparation method thereof.The preparation method comprises the following steps that a base material is treated, epoxy resin modified polyurethane, reinforcing filler, anti-corrosion filler, a curing agent and a solvent are sequentially added according to a preset proportion and mixed to be uniform, primer is prepared, and the base material is sprayed with the primer; and then taking the isoxazole modified polyurea as finish paint, and spraying the finish paint on one side, deviating from the base material, of the primer to obtain the protective coating. The protective coating has excellent waterproof performance, impact resistance, wear resistance and organism adhesion resistance, and can effectively prevent corrosion factors such as moisture and various ions in seawater and various fouling organisms such as barnacles, mussels, oysters and sponges in seawater from being in contact with the surface of a base material.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a deep-sea pressure-resistant shell protective coating and a preparation method thereof. Background Art

[0002] Marine equipment and facilities such as offshore platforms, ships, submersibles, and oil and gas development will experience wear and corrosion when working in the marine environment for a long time. Various organisms and inorganic substances in the deep sea will also cause friction or even collision with them, thus affecting the service life and safety of marine equipment. At present, the parts of marine equipment are mainly made of metal materials such as titanium alloys and aluminum alloys. The surface hardness of the above metal materials is low and the shear resistance is poor. The transmission, sliding, friction between parts and parts, and the particle scouring in seawater will cause material wear, resulting in system damage and failure. In addition, because marine equipment has been affected by seawater corrosion behaviors such as chloride ion pitting and oxidation for a long time, the corrosion products will also aggravate the friction, adhesion and even "bite" between parts and components, and ultimately can only be destroyed and disassembled, significantly increasing the maintenance cost and difficulty of marine equipment. Therefore, the coupling damage of wear and corrosion has become a major technical problem faced by marine equipment parts.

[0003] In the marine environment, applying an organic coating on the metal surface is one of the most effective anti-corrosion methods. The organic coating is tightly attached to the surface of the substrate, which can block oxygen and slow down the penetration of water molecules and other corrosive ions, providing effective protection for the substrate. However, the coating materials in the prior art often have a single function and cannot meet the complex and changeable performance index requirements in the deep-sea service environment. For example, epoxy anti-corrosion coatings have the advantages of high adhesion, high strength, chemical resistance and wear resistance, but they are relatively brittle and have low heat resistance; polyurethane anti-corrosion coatings are hard and have strong adhesion, but have poor weather resistance; polyurea anti-corrosion coatings have good high and low temperature resistance, but general mechanical properties. The above-mentioned shortcomings limit the application of protective coatings in the deep-sea field. Therefore, it is necessary to provide a deep-sea pressure-resistant shell protective coating to solve the above problems. Summary of the invention

[0004] Based on the above, the purpose of the present invention is to provide a deep-sea pressure-resistant shell protective coating and a preparation method thereof, to provide protection for marine equipment and significantly improve the anti-corrosion, anti-collision, wear-resistant and anti-biological attachment properties of marine equipment.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A deep-sea pressure-resistant shell protective coating comprises a primer and a topcoat, wherein the primer comprises epoxy resin-modified polyurethane and the topcoat comprises isoxazole-modified polyurea.

[0006] As a preferred solution for a protective coating for a deep-sea pressure-resistant hull, the primer comprises epoxy resin-modified polyurethane, a curing agent, a reinforcing filler, an anti-corrosion filler and a solvent; the mass ratio of the epoxy resin-modified polyurethane, the curing agent, the reinforcing filler, the anti-corrosion filler and the solvent is 1: (0.4~1): (0.1~0.2): (0.2~0.45): (1~1.4).

[0007] As a preferred solution for the protective coating of a deep-sea pressure-resistant hull, the curing agent includes an amine curing agent, specifically a compound of modified triethylenetetramine and T-31 curing agent, and the compounding ratio of the modified triethylenetetramine and T-31 curing agent is 1: (2~4).

[0008] As a preferred solution for a protective coating for a deep-sea pressure-resistant shell, the solvent includes one or more of xylene and ethyl acetate; the reinforcing filler includes fumed silica; and the anti-corrosion filler includes one or more of zinc phosphate, aluminum tripolyphosphate, and glass flakes.

[0009] As a preferred solution for the protective coating of a deep-sea pressure-resistant shell, the preparation process of the isoxazole-modified polyurea includes: adding ethyl acetate to an olefin-terminated polyurea resin, stirring and mixing, filtering to obtain a mixture, and stirring and mixing the mixture with phenyl nitrone according to a preset ratio to obtain the isoxazole-modified polyurea; Wherein, the mass ratio of the alkenyl-terminated polyurea resin to the ethyl acetate is 1:(1-1.5), and the mass ratio of the mixture to the phenylnitrone is (2-2.5):1.

[0010] As a preferred solution for the protective coating of a deep-sea pressure-resistant hull, the thickness of the primer is 0.2-0.4 mm, and the thickness of the topcoat is 0.4-0.6 mm.

[0011] A method for preparing a deep-sea pressure-resistant hull protective coating, based on any of the deep-sea pressure-resistant hull protective coatings described above, comprises the following steps: Substrate treatment; Adding preset proportions of epoxy resin modified polyurethane, reinforcing filler, anticorrosive filler, curing agent and solvent in sequence and mixing evenly to prepare a primer, and spraying the primer on the substrate; The isoxazole-modified polyurea is used as a topcoat, and the topcoat is sprayed on the side of the primer away from the substrate to obtain a protective coating.

[0012] As a preferred embodiment of the method for preparing a protective coating for a deep-sea pressure-resistant hull, the conditions for the primer and topcoat spraying process include: a temperature of 22-30°C, a humidity of 50-80%, automatic spraying, a spray distance of 10-15 cm, and a spraying time interval of 10 min / pass.

[0013] As a preferred solution for the preparation method of a deep-sea pressure-resistant shell protective coating, during the preparation process of the primer and the topcoat, they are naturally dried after spraying and then polished and trimmed.

[0014] As a preferred solution of a method for preparing a protective coating for a deep-sea pressure-resistant shell, the specific process of substrate treatment includes: Polishing, cleaning and drying the surface of the substrate, applying a coupling agent on the dried surface of the substrate, and drying naturally; The coupling agent includes an epoxy silane coupling agent.

[0015] The beneficial effects of the present invention are: The present invention provides a deep-sea pressure-resistant shell protective coating, which includes a primer and a topcoat arranged in sequence, wherein the primer includes epoxy resin modified polyurethane, and the topcoat includes isoxazole modified polyurea. The primer can be firmly bonded to the metal substrate by modifying the polyurethane, and the polyurea is modified by a click reaction of nitrone so that the modified polyurea can be tightly combined with the primer, thereby enhancing the waterproof performance, impact resistance and wear resistance of the protective coating, improving the tear strength and elongation at break of the protective coating, and improving the anti-biological adhesion ability of the protective coating. The isoxazole obtained by the reaction of olefins and nitrone usually has antibacterial and cytotoxic properties. The organic combination of the two allows the coating to be tightly connected to the surface of the substrate, which can effectively prevent moisture, various ions in seawater and other corrosive factors, various fouling organisms in seawater such as barnacles, mussels, oysters and sponges from contacting the surface of the substrate, and has excellent anti-collision and wear resistance.

[0016] The density of the deep-sea pressure-resistant shell protective coating prepared in this application is less than or equal to 1.1 g / cm 3 , thickness is 0.6~1.0 mm, the bonding strength between the protective coating and the substrate is greater than or equal to 1.5 MPa, and the shear strength of the protective coating is greater than or equal to 2.5 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0018] Figure 1 is a schematic diagram of the structure of the protective coating provided by the present invention; Figure 2 is a flow chart of a method for preparing a protective coating provided by the present invention; Figure 3It is the chemical reaction formula of the preparation process of bisphenol A epoxy resin modified polyurethane; Figure 4 yes Figure 3 Chemical structure diagram of R1; Figure 5 yes Figure 3 The chemical structure diagram of R2; Figure 6 yes Figure 3 Chemical structure diagram of R3; Figure 7 It is the chemical reaction formula of the preparation process of isoxazole-modified polyurea; Figure 8 yes Figure 7 Chemical structure diagram of R1; Fig. 9 This is a surface morphology diagram of the protective coating prepared in Example 1 of the present invention after the primer is sprayed; Fig.10 This is a surface morphology diagram of the protective coating prepared in Example 1 of the present invention after the topcoat spraying is completed; Fig.11 This is an ultrasonic flaw detection photograph of the protective coating prepared in Example 1 of the present invention before external pressure fatigue; Fig.12 This is an ultrasonic flaw detection photograph of the protective coating prepared in Example 1 of the present invention after external pressure fatigue; Fig.13 This is a CT scan photo of the shell after the protective coating prepared in Example 1 of the present invention is fatigued by external pressure; Fig.14 This is a surface morphology diagram of the protective coating prepared in Example 2, Example 3, and Example 4 of the present invention after spraying; Fig.15 This is the surface morphology of the protective coating prepared in Example 2, Example 3, and Example 4 of the present invention after the water absorption test is completed; Fig.16 This is a picture of the hull surface of the Insight unmanned autonomous submersible one year after use. DETAILED DESCRIPTION

[0019] For ease of understanding of the present invention, the present invention will be described more fully below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Unless otherwise defined, all technical and scientific terms used in the present invention belong to the technical field of the present invention.

[0020] This embodiment provides a deep-sea pressure-resistant hull protective coating, which includes a primer and a topcoat, wherein the primer includes epoxy resin-modified polyurethane and the topcoat includes isoxazole-modified polyurea. The thickness of the primer is 0.2-0.4 mm, and the thickness of the topcoat is 0.4-0.6 mm. The structural schematic diagram of the protective coating is shown in FIG. Figure 1 As shown, 1 is the substrate, 2 is the primer, and 3 is the topcoat.

[0021] Specifically, the primer includes epoxy resin modified polyurethane, curing agent, reinforcing filler, anti-corrosion filler and solvent; the mass ratio of epoxy resin modified polyurethane, curing agent, reinforcing filler, anti-corrosion filler and solvent is 1: (0.4~1): (0.1~0.2): (0.2~0.45): (1~1.4). In this embodiment, the mass ratio is preferably 1: 0.4: 0.1: 0.32: 1.4. Of course, in other embodiments, the mass ratio can also be selected as 1: 1: 0.2: 0.2: 1 or 1: 0.7: 0.15: 0.45: 1.2, which is determined according to actual conditions. The curing agent includes a compound amine curing agent, specifically a compound of modified triethylenetetramine and T-31 curing agent, and the compounding ratio is 1: (2~4). In this embodiment, it is preferably 1:3. Of course, in other embodiments, it can also be selected as 1:2 or 1:4, which is determined according to actual conditions; the solvent includes one or more of xylene and ethyl acetate; the reinforcing filler includes fumed silica; the anti-corrosion filler includes one or more of zinc phosphate, aluminum tripolyphosphate, and glass flakes.

[0022] Specifically, the epoxy resin modified polyurethane includes bisphenol A epoxy resin modified polyurethane, and the preparation process of bisphenol A epoxy resin modified polyurethane includes main reaction 1 and reaction 2. The chemical reaction formula is as follows: Figure 3 As shown, Figure 3 In the formula, the chemical structures of R1, R2 and R3 are as follows: Figure 4 , Figure 5 , Figure 6 As shown, R1 is a 2,6-disubstituted toluene group, R2 is a dipentyl ketone group, and R3 is a bisphenol A epoxy resin group. In R3, the group segment indicated by arrow 1 specifically improves its flexibility, the group segment indicated by arrow 2 specifically improves its heat resistance and toughness, the group indicated by arrow 3 specifically improves its chemical resistance, and the group indicated by arrow 4 specifically improves its adhesion or reactivity.

[0023] Specifically, the preparation process of the isoxazole-modified polyurea includes: adding ethyl acetate to an olefin-terminated polyurea resin for dilution, stirring and mixing, filtering to obtain a mixture, stirring and mixing the mixture with phenylnitrone according to a preset ratio to obtain an isoxazole-modified polyurea; wherein the mass ratio of the olefin-terminated polyurea resin to the ethyl acetate is 1:(1-1.5), preferably 1:1.2 in this embodiment, and can be optionally 1:1 or 1:1.5 in other embodiments, which is determined according to actual conditions; the mass ratio of the mixture to the phenylnitrone is (2-2.5):1, preferably 2.2:1 in this embodiment, and can be optionally 2:1 or 2.5:1 in other embodiments, which is determined according to actual conditions.

[0024] The preparation process of isoxazole-modified polyurea includes the main reactions 3, 4 and 5 (click reaction of nitrone), and the chemical reaction formula is as follows: Figure 7 As shown, Figure 7 In the figure, R1 is methylene dicyclohexyl, R2 is polydimethylsiloxane, R3 is CH2, R4 is Bn, R5 is Ph, and the chemical structure of R1 is shown in the figure below: Figure 8 shown.

[0025] This embodiment also provides a method for preparing a protective coating for a deep-sea pressure-resistant shell. Figure 2 As shown, the specific steps include: S100, substrate treatment; Specifically, the substrate treatment process includes: polishing the substrate surface, cleaning, drying, applying a coupling agent on the dried substrate surface, and drying naturally; the coupling agent includes an epoxy silane coupling agent, specifically silane coupling agent KH-570.

[0026] S200, spraying a primer on the substrate; sequentially adding a preset proportion of epoxy resin modified polyurethane, reinforcing filler, anticorrosive filler, curing agent and solvent and mixing them evenly to prepare a primer, and spraying the primer on the substrate; Specifically, the conditions of the primer spraying process include: temperature of 22~30℃, humidity of 50~80%, automatic spraying, spray distance of 10~15 cm, spraying time interval of 10 min / pass; after spraying, let it dry naturally and polish it.

[0027] Specifically, the primer includes epoxy resin modified polyurethane, curing agent, reinforcing filler, anti-corrosion filler and solvent; the mass ratio of epoxy resin modified polyurethane, curing agent, reinforcing filler, anti-corrosion filler and solvent is 1: (0.4~1): (0.1~0.2): (0.2~0.45): (1~1.4). In this embodiment, the mass ratio is preferably 1: 0.4: 0.1: 0.32: 1.4. Of course, in other embodiments, the mass ratio can also be selected as 1: 1: 0.2: 0.2: 1 or 1: 0.7: 0.15: 0.45: 1.2, which is determined according to actual conditions. The curing agent includes a compound amine curing agent, specifically a compound of modified triethylenetetramine and T-31 curing agent, and the compounding ratio is 1: (2~4). In this embodiment, it is preferably 1:3. Of course, in other embodiments, it can also be selected as 1:2 or 1:4, which is determined according to actual conditions; the solvent includes one or more of xylene and ethyl acetate; the reinforcing filler includes fumed silica; the anti-corrosion filler includes one or more of zinc phosphate, aluminum tripolyphosphate, and glass flakes.

[0028] Preferably, after spraying the primer on the substrate, a second primer spraying can be performed, and the reaction conditions are the same as the first primer spraying. After the spraying is completed, it is naturally dried and polished and trimmed.

[0029] S300, spray the topcoat on the side of the primer facing away from the substrate to obtain a protective coating.

[0030] Specifically, the conditions of the topcoat spraying process include: temperature of 22~30℃, humidity of 50~80%, automatic spraying, spraying distance of 10~15 cm (such as 10 cm, 11 cm, 12 cm, 13 cm, 14 cm or 15 cm), spraying time interval of 10 min / pass; after spraying, let it dry naturally and polish it.

[0031] The present invention will be further described below by means of specific examples. Example 1

[0032] A method for preparing a protective coating for a deep-sea pressure-resistant shell: The surface of the shell substrate was polished, and its surface was cleaned with water and ethanol in turn, and dried thoroughly. After drying, silane coupling agent KH-570 was applied on the surface of the shell substrate and dried naturally.

[0033] Prepare the primer, spray the primer on the shell substrate, first, add 100 g epoxy resin modified polyurethane, 10 g reinforcing filler fumed silica and 32.25 g anti-corrosion filler zinc phosphate in sequence, wherein each filler is stirred and mixed, and a three-roll mill is used for mixing 3 to 4 times, so that the fineness of the mixed filler is maintained at 10 to 15 μm. Then add the curing agent (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent, wherein the modified triethylenetetramine curing agent needs to be added first, stirred and mixed, and then the first-generation T-31 curing agent is added and stirred and mixed), and then add 142.25 g of xylene solvent and stir and mix. Then add the curing agent again (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent), stir and mix, and prepare the primer. Then spray the primer on the shell substrate. During the primer spraying process, the temperature is 22~30℃ and the humidity is 50~80%. Use an automatic spraying system, control the spray distance at 15 cm, and the spraying time interval is 10 min / pass. After spraying, let it dry naturally for 24 hours. Repeat the above primer spraying operation for the second time, let it dry naturally after spraying, and polish it.

[0034] Prepare a topcoat, spray the topcoat on the side of the primer away from the shell substrate to obtain a protective coating. Add 120 g of ethyl acetate to 100 g of olefin-terminated polyurea resin for dilution, stir and mix, filter through a 400-mesh gauze under normal pressure to obtain a mixture, then add 1 part of phenyl nitrone to every 2.2 parts of the mixture, and stir and mix. Prepare a topcoat. Then spray the topcoat on the side of the primer away from the shell substrate. During the topcoat spraying process, use an automatic spraying system at a temperature of 22~30°C and a humidity of 50~80%, control the spray distance at 15 cm, and the spraying time interval is 10 min / pass. After spraying, let it dry naturally for 24 hours. And grind and trim it. Obtain the protective coating required for this embodiment. The surface morphology of the protective coating after the primer and topcoat are sprayed are as follows: Fig. 9 and Fig.10 shown.

[0035] The shell protective coating was tested for relevant performances, and the specific test standards include: GB / T 7124-2008 Adhesive. Tensile shear strength test standard; GB1040-79 tensile strength test standard; GB / T 16578.1-2008 tear strength test standard.

[0036] The test results show that the shear tensile strength of the shell protective coating and the shell substrate is greater than 3.38 MPa. The tensile strength of the primer itself is greater than 21.5 MPa, the tear elongation is less than 18.1%, the tensile strength of the topcoat is about 5.2 MPa, the tear elongation is about 260%, and the breaking force is about 63.5 N, which has very good toughness and strength. The tensile strength between the components of the shell protective coating is greater than 1.1 MPa; the adhesion between the primer and the intermediate paint, and the intermediate paint and the topcoat, the damage type is the body damage, the overall appearance of the shell protective coating is smooth and flat, without sagging, shrinkage, blistering, orange peel, and there are no gaps and pits at the skirt end.

[0037] Fig.11 and Fig.12 The ultrasonic flaw detection photos of the inside of the shell before and after 3000 external pressure fatigue tests are shown. The comparison shows that there is no obvious debonding defect between the coating and the substrate before and after the external pressure fatigue test, and there is a small debonding defect between the coatings. Fig.13 The CT scan photo of the shell after 3000 times of external pressure fatigue shows that the above-mentioned debonding defect occurs in the winding layer, and there is no debonding between the topcoat polyurea coating and the winding layer. The surface coatings are tightly bonded. Example 2

[0038] A method for preparing a protective coating for a deep-sea pressure-resistant shell: The surface of the 20х20 cm aluminum alloy substrate was polished, cleaned with water and ethanol in turn, and dried thoroughly. After drying, the silane coupling agent KH-570 was applied on the surface of the substrate and dried naturally.

[0039] Prepare the primer, spray the primer on the substrate, first, add 100 g epoxy resin modified polyurethane, 10 g reinforcing filler fumed silica and 32.25 g anti-corrosion filler aluminum tripolyphosphate in sequence, wherein each filler is stirred and mixed, and a three-roll mill is used for mixing 3 to 4 times, so that the fineness of the mixed filler is maintained at 10 to 15 μm. Then add the curing agent (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent, wherein the modified triethylenetetramine curing agent needs to be added first, stirred and mixed, and then the first-generation T-31 curing agent is added and stirred and mixed), and then add 142.25 g of xylene solvent and stir and mix. Then add the curing agent again (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent), stir and mix, and prepare the primer. Then spray the primer on the substrate. During the primer spraying process, use an automatic spraying system at a temperature of 22-30°C and a humidity of 50-80%, control the spray distance at 14 cm, and spray the surface for 10 min / pass. After spraying, let it dry naturally for 24 hours. Repeat the above primer spraying operation for the second primer spraying. After spraying, let it dry naturally and polish it.

[0040] Prepare a topcoat, spray the topcoat on the side of the primer away from the substrate to obtain a protective coating. Add 120 g of ethyl acetate solvent to 100 g of olefin-terminated polyurea for dilution, stir and mix, filter through a 400-mesh gauze under normal pressure to obtain a mixture, then add 1 part of phenyl nitrone to every 2.2 parts of the mixture, and stir and mix. Prepare a topcoat. Then spray the topcoat on the side of the primer away from the substrate. During the topcoat spraying process, use an automatic spraying system at a temperature of 22 to 30°C and a humidity of 50 to 80%, control the spray distance at 13 cm, and the spraying time interval is 10 min / pass. After spraying, dry naturally for 24 hours. And polish and trim it. Obtain the protective coating required for this embodiment.

[0041] The relevant performance tests of the shell protective coating are carried out. Since the contact angle of the anti-corrosion coating in the seawater environment is greater than or equal to 124.5°, it is hydrophobic (the contact angle of conventional polyurea not modified with isoxazole with water is about 78~79°, which is hydrophilic). The water absorption rate of the protective coating prepared in this application is less than or equal to 0.3%. The average value is taken by measuring three times with a contact angle tester to obtain the contact angle of the protective coating with water. After testing, the average contact angle of the protective coating with water is 124.5°, and the water absorption rate of the latex film water resistance determination is only 0.25%. The surface is smooth after blisters, without loss of gloss, discoloration, bubbles, wrinkling, shedding and other phenomena. The water absorption rate is less than that of ordinary polyurea, indicating that the coating material has a high density, strong hydrophobicity, and can remain stable for a long time in a deep-sea working environment. Example 3

[0042] A method for preparing a protective coating for a deep-sea pressure-resistant shell: The surface of a 20х20 cm titanium alloy substrate was polished, cleaned with water and ethanol in turn, and dried thoroughly. After drying, silane coupling agent KH-570 was applied on the surface of the substrate and dried naturally.

[0043] Prepare the primer, spray the primer on the substrate, first, add 100 g epoxy resin modified polyurethane, 10 g reinforcing filler fumed silica and 32.25 g anti-corrosion filler glass flakes in sequence, wherein each filler is stirred and mixed, and a three-roll mill is used for mixing 3 to 4 times, so that the fineness of the mixed filler is maintained at 10 to 15 μm. Then add the curing agent (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent, wherein the modified triethylenetetramine curing agent needs to be added first, stirred and mixed, and then the first-generation T-31 curing agent is added, and stirred and mixed), and then add 142.25 g of xylene solvent, and stir and mix. Then add the curing agent again (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent), stir and mix, and prepare the primer. Then spray the primer on the substrate. During the primer spraying process, use an automatic spraying system in an environment with a temperature of 22-30°C and a humidity of 50-80%, control the spray distance at 10 cm, and spray the surface for 10 min / pass. After spraying, let it dry naturally for 24 hours. Repeat the above primer spraying operation for the second primer spraying, let it dry naturally after spraying, and polish and trim it.

[0044] Prepare a topcoat, spray the topcoat on the side of the primer away from the substrate to obtain a protective coating. Add 120 g of ethyl acetate solvent to 100 g of olefin-terminated polyurea resin for dilution, stir and mix, filter through a 400-mesh gauze under normal pressure to obtain a mixture, then add 1 part of phenyl nitrone to every 2.2 parts of the mixture, and stir and mix. Prepare a topcoat. Then spray the topcoat on the side of the primer away from the shell substrate. During the topcoat spraying process, use an automatic spraying system at a temperature of 22 to 30°C and a humidity of 50 to 80%, control the spray distance at 10 cm, and the spraying time interval is 10 min / pass. After spraying, dry naturally for 24 hours. And polish and trim it. Obtain the protective coating required for this embodiment.

[0045] The protective coating was tested for relevant properties. Since the contact angle of the anti-corrosion coating in the seawater environment is greater than or equal to 124.5°, it is hydrophobic (the contact angle of conventional polyurea not modified with isoxazole with water is about 78-79°, which is hydrophilic). The water absorption rate of the protective coating prepared in this application is less than or equal to 0.3%. The average value was taken by measuring three times with a contact angle tester to obtain the contact angle between the protective coating and water. After testing, the average contact angle between the protective coating and water is 125.0°, and the water absorption rate of the latex film water resistance determination is only 0.3%. The surface is smooth after blisters, without loss of gloss, discoloration, bubbles, wrinkling, shedding and other phenomena. The water absorption rate is lower than that of ordinary polyurea, indicating that the coating material has a high density, strong hydrophobicity, and can remain stable for a long time in a deep-sea working environment. Example 4

[0046] A method for preparing a protective coating for a deep-sea pressure-resistant shell: The surface of the carbon fiber substrate was polished, and its surface was cleaned with water and ethanol in turn, and dried thoroughly. After drying, silane coupling agent KH-570 was applied on the surface of the substrate and dried naturally.

[0047] Prepare the primer and spray the primer on the substrate. First, add 100 g epoxy resin modified polyurethane, 10 g reinforcing filler fumed silica and 32.25 g anti-corrosion filler zinc phosphate in sequence. Each time a filler is added, it is stirred and mixed, and a three-roll mill is used for mixing 3 to 4 times to keep the fineness of the mixed filler at 10 to 15 μm. Then add the curing agent (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent, where the modified triethylenetetramine curing agent needs to be added first, stirred and mixed, and then the first-generation T-31 curing agent is added and stirred and mixed), and then add 142.25 g of xylene solvent and stir and mix. Then add the curing agent again (4 g modified triethylenetetramine curing agent and 17.6 g first-generation T-31 curing agent), stir and mix, and prepare the primer. Then spray the primer on the substrate. During the primer spraying process, use an automatic spraying system at a temperature of 22-30°C and a humidity of 50-80%. The spray distance is controlled at 15 cm, the spraying time interval is 10 min / pass, and the surface is naturally dried for 24 hours after spraying. Repeat the above primer spraying operation for the second primer spraying, let it dry naturally after spraying, and polish and trim it.

[0048] Prepare a topcoat, spray the topcoat on the side of the primer away from the substrate to obtain a protective coating. Add 120 g of ethyl acetate to 100 g of olefin-terminated polyurea resin for dilution, stir and mix, filter in a 400-mesh gauze under normal pressure to obtain a mixture, then add 1 part of phenyl nitrone to every 2.2 parts of the mixture, stir and mix, and prepare a topcoat. Then spray the topcoat on the side of the primer away from the shell substrate. During the topcoat spraying process, use an automatic spraying system at a temperature of 22-30°C and a humidity of 50-80%, control the spray distance at 15 cm, and spray at a time interval of 10 min / pass. After spraying, dry naturally for 24 hours. And polish and trim it. Obtain the protective coating required for this embodiment.

[0049] The protective coating was tested for relevant properties. Since the contact angle of the anti-corrosion coating in the seawater environment is greater than or equal to 124.5°, it is hydrophobic (the contact angle of conventional polyurea not modified with isoxazole with water is about 78~79°, which is hydrophilic). The water absorption rate of the protective coating prepared in this application is less than or equal to 0.3%. The average value was taken by measuring three times with a contact angle tester to obtain the contact angle between the protective coating and water. After testing, the average contact angle between the protective coating and water is 124.0°, and the water absorption rate of the latex film water resistance determination is only 0.28%. The surface is smooth after blisters, without loss of gloss, discoloration, bubbles, wrinkling, shedding and other phenomena. The water absorption rate is less than that of ordinary polyurea, indicating that the coating material has a high density, strong hydrophobicity, and can remain stable for a long time in a deep-sea working environment.

[0050] Fig.14 This is the surface morphology of the protective coating prepared in Example 2, Example 3, and Example 4 after spraying. Fig.15 The surface morphology of the protective coatings prepared in Example 2, Example 3, and Example 4 after the water absorption test shows that after the water absorption test, the surface of the protective coating is smooth without loss of gloss, discoloration, bubbles, wrinkles, or falling off, indicating that the coating material has high density and strong hydrophobicity, and can remain stable for a long time in a deep-sea working environment. Fig.16 This is the surface picture of the shell of the "Insight" unmanned autonomous submersible after one year of use. The overall surface morphology of the shell protective coating is smooth and flat, without sagging, shrinkage holes, bubbles, orange peel, and there are no gaps and pits at the skirt end. This shows that the protective coating has anti-corrosion, anti-collision, wear-resistant, and anti-biological attachment properties, and can remain stable for a long time in the deep-sea working environment.

[0051] The above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A deep-sea pressure-resistant shell protective coating, characterized in that: The invention comprises a primer and a topcoat, wherein the primer comprises epoxy resin-modified polyurethane and the topcoat comprises isoxazole-modified polyurea.

2. The deep-sea pressure hull protective coating according to claim 1, characterized in that: The primer comprises epoxy resin modified polyurethane, curing agent, reinforcing filler, anticorrosive filler and solvent; The mass ratio of the epoxy resin modified polyurethane, curing agent, reinforcing filler, anti-corrosion filler and solvent is 1: (0.4-1): (0.1-0.2): (0.2-0.45): (1-1.4).

3. The deep-sea pressure hull protective coating according to claim 2, characterized in that: The curing agent includes an amine curing agent, specifically a compound of modified triethylenetetramine and T-31 curing agent, and the compounding ratio of the modified triethylenetetramine and T-31 curing agent is 1: (2~4).

4. The deep-sea pressure hull protective coating according to claim 2, characterized in that: The solvent includes one or more of xylene and ethyl acetate; the reinforcing filler includes fumed silica; and the anti-corrosion filler includes one or more of zinc phosphate, aluminum tripolyphosphate, and glass flakes.

5. The deep-sea pressure hull protective coating according to claim 1, characterized in that: The preparation process of the isoxazole-modified polyurea comprises: Adding ethyl acetate to the alkenyl-terminated polyurea resin, stirring and mixing, filtering to obtain a mixture, and stirring and mixing the mixture with phenyl nitrone according to a preset ratio to obtain an isoxazole-modified polyurea; Wherein, the mass ratio of the alkenyl-terminated polyurea resin to the ethyl acetate is 1:(1-1.5), and the mass ratio of the mixture to the phenylnitrone is (2-2.5):

1.

6. The deep-sea pressure hull protective coating according to claim 1, characterized in that: The thickness of the primer is 0.2-0.4 mm, and the thickness of the topcoat is 0.4-0.6 mm.

7. A method for preparing a deep-sea pressure-resistant shell protective coating, based on the deep-sea pressure-resistant shell protective coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: Substrate treatment; Adding preset proportions of epoxy resin modified polyurethane, reinforcing filler, anticorrosive filler, curing agent and solvent in sequence and mixing evenly to prepare a primer, and spraying the primer on the substrate; The isoxazole-modified polyurea is used as a topcoat, and the topcoat is sprayed on the side of the primer away from the substrate to obtain a protective coating.

8. The method for preparing a protective coating for a deep-sea pressure-resistant shell according to claim 7, characterized in that: The conditions of the primer and topcoat spraying process include: temperature of 22-30° C., humidity of 50-80%, automatic spraying, spraying distance of 10-15 cm, and spraying time interval of 10 min / pass.

9. The method for preparing a protective coating for a deep-sea pressure-resistant shell according to claim 7, characterized in that: During the preparation of the primer and the topcoat, the primer and the topcoat are naturally dried after spraying, and then polished and trimmed.

10. The method for preparing a protective coating for a deep-sea pressure-resistant shell according to claim 7, characterized in that: The specific process of substrate treatment includes: Polishing, cleaning and drying the surface of the substrate, applying a coupling agent on the dried surface of the substrate, and drying naturally; The coupling agent includes an epoxy silane coupling agent.

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