Anti-corrosion coating for submarine conveying pipeline and preparation process of anti-corrosion coating

Abstract

The invention discloses an anti-corrosion coating for a submarine conveying pipeline, which comprises three parts, namely a primer, a middle coating and a finishing coat, aims to provide efficient anti-corrosion protection, and comprises an epoxy resin primer and a modified epoxy resin middle coating finishing coat which are composed of hydroxy acrylic resin, an aliphatic isocyanate curing agent, flaky aluminum powder, glass flakes, an ultraviolet light absorber and the like. The anti-corrosion coating is suitable for anti-corrosion protection of seabed conveying pipelines, and has good durability and environmental protection property. The paint has the beneficial effects that a coating layer formed by the paint has a synergistic effect, the corrosion resistance is greatly enhanced, and the service life of a pipeline can be prolonged due to the self-repairing characteristic of finish paint; the coating obtained by the coating has the advantages of strong adhesion ability, good toughness, high strength and strong adaptability to seabed environment, can be used for most of marine pipeline engineering, has strong anti-corrosion ability, is suitable for long-term use, and can effectively save the construction cost.

Description

Technical Field

[0001] The present invention relates to the technical field related to anti-corrosion coatings, and in particular to an anti-corrosion coating for submarine transmission pipelines and a preparation process thereof. Background Art

[0002] Subsea pipelines are crucial for transporting resources like oil and gas and are widely used in marine engineering. Due to the unique submarine environment, pipelines are subject to a variety of corrosive factors during operation. Metal corrosion is a phenomenon in which metals undergo chemical or electrochemical reactions under the influence of the surrounding environment, resulting in the destruction of their properties. Therefore, to reduce or even prevent metal corrosion, cathodic protection and coating methods are used to protect metals. Currently, one of the most common, convenient, and effective methods is to apply an anti-corrosion coating to the metal surface, isolating it from the external environment and achieving the desired corrosion protection.

[0003] The high salinity and unstable pH of ocean water, coupled with erosion from seabed sediments, make submarine pipelines susceptible to corrosion, impacting their long-term stability and service life. To address this issue, anti-corrosion coatings, a key technology for submarine pipeline protection, have become a hot topic of research and application both domestically and internationally.

[0004] Traditional anti-corrosion coatings usually use materials such as paint, epoxy resin, and polyurethane, but these coatings show certain limitations in the submarine environment. In high humidity, low temperature, and high salinity environments, traditional anti-corrosion coatings are prone to problems such as shedding, peeling, and cracking, which greatly reduces the protective effect of the coating. In addition, due to the poor performance of these coatings in terms of durability, resistance to UV rays, and resistance to marine microbial erosion, they cannot meet the protection needs under long-term and high-pressure conditions. In order to overcome these problems, many researchers have begun to explore new types of anti-corrosion coatings, focusing on improving the adhesion, weather resistance, corrosion resistance, and self-repairing capabilities of the coatings.

[0005] In recent years, with the continuous development of high-performance coating materials, new technologies such as nanotechnology and composite materials have been gradually applied to the preparation of anti-corrosion coatings. The addition of nanomaterials not only improves the mechanical properties of the coating but also enhances its corrosion resistance, sealing, and impermeability, thereby improving the protective effect of pipelines. Composite coating technology, by combining the advantages of different materials, improves the overall performance of the coating, especially in terms of corrosion resistance, heat resistance, and pressure resistance.

[0006] However, existing submarine pipeline anti-corrosion coatings still face several technical challenges. For example, the production cost of existing coatings is high, and the coating's stability and durability in extreme marine environments still need to be further improved. Therefore, the development of a new, efficient, low-cost, and highly durable submarine pipeline anti-corrosion coating has become a pressing technical challenge.

[0007] This patented technology is proposed to solve the above problems and provides a new type of anti-corrosion coating for submarine transmission pipelines and its preparation process. By optimizing the composition and preparation process of the coating, the corrosion resistance, durability and economy of the coating are improved, thereby providing longer-term protection for submarine pipelines. Summary of the Invention

[0008] In view of the above shortcomings, the present invention adopts the following technical solutions:

[0009] Primer: 15-20 parts of epoxy resin E-44 or E-51, 6-7 parts of cardanol modified amine curing agent (NX-2003), 60-70 parts of flaky zinc powder, 0.3-0.4 parts of polyamide wax, 1-2 parts of fumed silica, 5-10 parts of phosphate, 3-5 parts of PVB toughening resin, defoamer BYK-066N, 0.5-0.8 parts of silane coupling agent, 1-1.2 parts of dispersant, 10-12 parts of solvent propylene glycol methyl ether acetate PMA: butanol mixed solution in a volume ratio of 3:1;

[0010] Medium coating: 70-80 parts of modified epoxy resin, 25-35 parts of polyamide curing agent 650#, 1-2 parts of silane coupling agent, 8-12 parts of zinc-aluminum composite powder, 5-8 parts of phosphate compound corrosion inhibitor, 3-5 parts of liquid polysulfide rubber LP-3, 3-5 parts of PVB toughening resin, 3-5 parts of polyaspartic acid ester, 0.5-1.5 parts of graphene, 0.8-1.0 parts of anti-settling agent organic bentonite, 1-1.2 parts of thixotropic agent fumed silica, 0.5-0.7 parts of silicone defoaming agent BYK-066N, 80-100 parts of mica iron oxide, 30-50 parts of glass flakes, 1.2-1.5 parts of dispersant BYK-163, 10-15 parts of a mixed solution of propylene glycol methyl ether acetate PMA: butanol in a volume ratio of 3:1;

[0011] Topcoat: 50-55 parts of hydroxy acrylic resin, 22-25 parts of aliphatic isocyanate curing agent HDI trimer, 12-15 parts of flaky aluminum powder, 18-20 parts of glass flakes, 0.3-0.5 parts of graphene oxide, 1.2-1.5 parts of silane coupling agent KH-560, 2-3 parts of epoxy tackifying resin Nan Ya E-20, 1.5-2 parts of ultraviolet absorber, 1-1.2 parts of dispersant, 0.4-0.5 parts of organic bentonite, 0.4-0.5 parts of fumed silica, 0.3-0.4 parts of defoaming agent, 15-18 parts of a mixed solution of solvent propylene glycol methyl ether acetate PMA: butyl acetate in a volume ratio of 3:1 (containing 0.5wt% molecular sieve dehydrating agent).

[0012] Furthermore, the specification of the flaky zinc powder in the primer is 800 mesh.

[0013] Furthermore, the silane coupling agents of the midcoat and primer are both aminosilane KH-550, the primer dispersant is polycarboxylate BYK-110, the phosphate in the primer is zinc phosphate and aluminum tripolyphosphate in a mass ratio of 1:1, and the molar ratio of aluminum tripolyphosphate P2O5 / Al2O3 is 3.0 to 3.2.

[0014] Furthermore, the preparation method of the modified epoxy resin comprises reacting polyetheramine Jeffamine D-400 with acryloyl chloride to generate polyether acrylamide, and then ring-opening and chain-extending the polyether acrylamide with epoxy resin SM828 to introduce a flexible segment to obtain the modified epoxy resin.

[0015] Furthermore, in the zinc-aluminum composite powder, Zn / Al=85 / 15, and the phosphate compound corrosion inhibitor is a compound of zinc phosphate and aluminum tripolyphosphate in a mass ratio of 5:3.

[0016] Furthermore, the flaky aluminum powder used in the topcoat is silane-coated flaky aluminum powder, and the flakes used are glass flakes with a high diameter-to-thickness ratio.

[0017] Furthermore, the ultraviolet absorber used in the topcoat is a composite reagent of Tinuvin 1130 and Tinuvin 400 in a mass ratio of 1:1.

[0018] Furthermore, the dispersant used in the topcoat is a compound of BYK-163 and BYK-2152 in a mass ratio of 1:1, and the defoamer used in the topcoat is a compound of BYK-066N and BYK-024 in a mass ratio of 1:1.

[0019] Furthermore, the solvent propylene glycol methyl ether acetate PMA: butyl acetate in a volume ratio of 3:1 contains 0.5 wt% of a molecular sieve dehydrating agent.

[0020] A preparation process for anti-corrosion coating of submarine transmission pipeline, comprising the following contents

[0021] Preparation process of primer:

[0022] Preparation process of primer:

[0023] D1. Raw material pretreatment

[0024] Place 800 mesh flaky zinc powder in an oven at 110°C and dry for 2 hours to remove moisture, then cool to room temperature for later use; weigh zinc phosphate and aluminum tripolyphosphate in a molar ratio of 1:1, add to a high-speed mixer, and premix at 800 rpm for 10 minutes to ensure uniform dispersion;

[0025] D2. Premix

[0026] Put 15-20 parts of epoxy resin E-44 or E-51 into a stirring kettle and stir at a low speed of 300 rpm. Then add 8-10 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol (3:1 by volume), 0.5-0.8 parts of defoamer BYK-066N, 1-1.2 parts of dispersant BYK-110, and 0.3-0.4 parts of polyamide wax in sequence. Heat to 40±2°C and stir for 15 minutes until completely dissolved.

[0027] D3. Filler dispersion

[0028] At 50°C, 60-70 parts of pretreated flaky zinc powder, 5-10 parts of phosphate mixture, and 1-2 parts of fumed silica were added to a stirred tank in three batches, with an interval of 5 minutes between each batch. The stirring speed was increased to 800 rpm and the dispersion was continued for 30 minutes. The mixture was then transferred to a sand mill and circulated for grinding until the fineness measured by a scraper fineness meter was ≤50 μm.

[0029] D4. Paint mixing

[0030] At 20-25°C, transfer the ground slurry to a paint mixing kettle, add 3-5 parts of PVB toughening resin and 0.5-0.8 parts of silane coupling agent KH-550, add the remaining solvent to adjust the viscosity, start vacuum degassing at -0.08 MPa, stir at 400 rpm, mix for 20 minutes, slowly add 6-7 parts of cardanol modified amine curing agent NX-2003, reduce the stirring speed to 200 rpm, and continue mixing for 15 minutes;

[0031] D5. Post-processing

[0032] At 20-25°C, sieve the prepared paint through a 200-mesh sieve to remove impurities, fill it into a light-proof sealed container, and mark the batch information;

[0033] Preparation process of coating:

[0034] Z1. Synthesis of polyether acrylamide

[0035] Jeffamine D-400 was dissolved in tetrachloromethane, and triethylamine was added as an acid binding agent in an amount of 1.2 times the molar amount of acryloyl chloride. Acryloyl chloride was added dropwise to the Jeffamine D-400 solution at 0-5°C until the molar ratio of acryloyl chloride reached 1:1.1. After the addition was completed, the temperature was raised to 25°C and the reaction was carried out for 4 hours. Unreacted acryloyl chloride and solvent were removed by distillation under reduced pressure. The product, polyether acrylamide, was a transparent viscous liquid. SM828 epoxy resin and polyether acrylamide were then mixed in a mass ratio of 1:0.3, and 0.5 wt% triethylbenzylammonium chloride (TEBAC) catalyst of SM828 epoxy resin was added. The mixture was stirred at a constant temperature of 80°C for 6 hours, and then deionized water was added to terminate the reaction. The modified epoxy resin was obtained after vacuum degassing.

[0036] Z2. Mixing and dispersion process

[0037] 70-80 parts of modified epoxy resin and 25-35 parts of polyamide 650# curing agent are mixed at room temperature at a stirring speed of 1,200 r / min for 30 minutes. 8-12 parts of zinc-aluminum composite powder, 80-100 parts of mica iron oxide, and 30-50 parts of glass flakes are added to ensure uniform dispersion of the filler. 1-2 parts of aminosilane KH-550, a silane coupling agent, are also added to promote compatibility between the resin and the filler to obtain a resin matrix.

[0038] Z3. Material Mixing

[0039] Premix 3-5 parts of liquid polysulfide rubber LP-3 with 3-5 parts of PVB resin, pre-react the thiol-epoxy group at 50°C for 1 hour, then blend with 3-5 parts of polyaspartic acid ester and stir evenly. Add to the resin matrix and mix evenly. Then add 0.5-1.5 parts of graphene, 1.2-1.5 parts of BYK-163 dispersant, and 5-8 parts of phosphate compound corrosion inhibitor. Stir at high speed for 1 hour to ensure uniform dispersion.

[0040] Z4. Adjust the properties of the coating

[0041] Add 0.8 parts of anti-settling agent organic bentonite to the above resin matrix to prevent solid filler precipitation, then add 1-1.2 parts of thixotropic agent fumed silica to improve the thixotropy of the coating and improve the coating properties, then add 0.5-0.7 parts of silicone defoamer BYK-066N to eliminate foam generated during the mixing process, stir evenly to allow these ingredients to be fully mixed with the resin matrix, then add 10-15 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol in a volume ratio of 3:1, stir evenly, adjust the viscosity and fluidity of the coating, and then stir comprehensively for 30 minutes;

[0042] Z5.Paint post-processing

[0043] Use a viscometer to test the viscosity of the coating to ensure it is suitable for coating. Perform a coating experiment to check the coating's adhesion, corrosion resistance, hardness and other properties. Finally, store the prepared coating in a sealed container to avoid volatilization and contamination. When using, apply and cure according to production requirements.

[0044] Preparation process of topcoat:

[0045] M1. Reaction of Hydroxylated Acrylic Resin with HDI Trimer

[0046] 50-55 parts of hydroxy acrylic resin and 22-25 parts of HDI trimer curing agent were mixed with 60% solvent (PMA: butyl acetate = 3:1), preheated at 60°C for 10 minutes, and HDI trimer was added dropwise at a rate of 0.5 mL / min under nitrogen protection. The reaction temperature was maintained at 75-80°C and the stirring rate was 300 rpm. After the addition was completed, the temperature was raised to 85°C and the reaction was continued for 2 hours. The NCO group content was monitored until it reached the theoretical value. The mixture was cooled to below 40°C, a dehydrating agent (0.5% molecular sieve) was added, and vacuum degassing was performed for 10 minutes.

[0047] M2. Dispersion process of fillers and functional additives

[0048] 2-3 parts of epoxy tackifying resin Nan Ya E-20 are added to the resin solution obtained in the previous step and mixed evenly. 12-15 parts of aluminum powder and silane coupling agent KH-560 (1.2-1.5 parts) are pre-reacted in ethanol and stirred at 60°C for 2 hours to form a silane coating to reduce the risk of galvanic corrosion. A sand mill with a zirconium bead diameter of 0.8 mm is used to grind to a fineness of ≤15 μm at a speed of 2000 rpm for 2 hours. 0.3-0.5 parts of graphene oxide and 1.2-1.5 parts of dispersant BYK-163 are used in combination, first pre-dispersed in 20% solvent, and then passed through a high shear emulsifier (10000 rpm, 30 min) to form a uniform conductive network. The treated graphene oxide, aluminum powder and glass flakes are sequentially added to the resin solution and stirred evenly. Then, 0.4-0.5 parts of organic bentonite and 0.4-0.5 parts of fumed silica HL-200 are added in sequence.

[0049] M3. Addition of additives

[0050] Add corresponding parts by weight of ultraviolet absorber and defoamer in sequence, stir for 30 minutes to mix evenly, and add the remaining amount of solvent to adjust the viscosity of the solution;

[0051] M4. Filtration and packaging

[0052] Filter through a 200-mesh filter, seal and store in a cool place at 10-30℃.

[0053] The present invention has the following beneficial effects: 1. The primer of the present invention is mainly used to provide corrosion protection, preventing moisture and corrosive substances from invading the pipeline surface. The coating's corrosion resistance is enhanced by ingredients such as flaky zinc powder and fumed silica. The midcoat provides a second layer of protection, enhances the adhesion of the primer, and increases the hardness and durability of the coating. The liquid polysulfide rubber can enhance the flexibility of the anti-corrosion layer to adapt to the dynamic environment of submarine pipelines. The topcoat provides a final protective layer, providing protection against ultraviolet rays, high temperature resistance, and increased hardness, further extending the service life. The multiple layers of coating can effectively prevent seawater corrosion and chemical erosion. 2. The coating formed by the coating of the present invention has a synergistic effect of the anti-corrosion ingredients in the topcoat, midcoat, and primer, greatly enhancing corrosion resistance and extending the practical life of the pipeline. 3. The coating obtained by the coating of the present invention has strong adhesion, good toughness, high strength, and strong adaptability to the submarine environment. It can be used in most marine pipeline projects, has strong corrosion resistance, is suitable for long-term engineering use, and can effectively save construction costs. DETAILED DESCRIPTION

[0054] The reagents used in the present invention are as follows:

[0055] Primer: epoxy resin E-44 or E-51, cardanol modified amine curing agent (NX-2003), flaky zinc powder 800 mesh, polyamide wax PA-8800, fumed silica HL-200, zinc phosphate and aluminum tripolyphosphate, PVB toughening resin, silane coupling agent KH-560, defoamer BYK-066N, dispersant BYK-110, solvent: propylene glycol methyl ether acetate PMA: butanol mixed solution with a volume ratio of 3:1;

[0056] Medium coating: modified epoxy resin, Jeffamine D-400, acryloyl chloride, triethylbenzylammonium chloride (TEBAC), polyamide curing agent 650#, silane coupling agent KH-560, zinc-aluminum composite powder Zn / Al=85 / 15 (800 mesh powder mixture), zinc phosphate, aluminum tripolyphosphate, liquid polysulfide rubber LP-3, PVB toughening resin, polyaspartic acid ester F520, graphene SE1233, anti-settling agent organic bentonite Hemmings Bentone SD-2, thixotropic agent fumed silica HL-200, silicone defoamer BYK-066N, mica iron oxide (MIO2000), glass flake Saint-Gobain Vetro 500, dispersant BYK-163, solvent propylene glycol methyl ether acetate PMA: butanol mixed solution (volume ratio 3:1) 10-15 parts;

[0057] Topcoat: Hydroxylated acrylic resin Aliphatic isocyanate curing agent HDI trimer Desmodur N3300, flaky aluminum powder 800 mesh, glass flake 400 mesh, graphene oxide SE2430, silane coupling agent KH-560, epoxy tackifying resin Nan Ya E-20, UV absorbers Tinuvin 1130 and Tinuvin 400, dispersants BYK-163 and BYK-2152, organic bentonite (Hemmings Bentone SD-2), fumed silica (HL-200), defoamers BYK-066N and BYK-024, solvent propylene glycol methyl ether acetate PMA: butyl acetate mixed solution in a volume ratio of 3:1 (containing 0.5wt% molecular sieve dehydrating agent).

[0058] Unless otherwise specified, all reagents used in the present invention were purchased from the market.

[0059] Preparation process of primer:

[0060] D1. Raw material pretreatment

[0061] Place 800 mesh flaky zinc powder in an oven at 110°C and dry for 2 hours to remove moisture, then cool to room temperature for later use; weigh zinc phosphate and aluminum tripolyphosphate in a molar ratio of 1:1, add to a high-speed mixer, and premix at 800 rpm for 10 minutes to ensure uniform dispersion;

[0062] D2. Premix

[0063] Put 15-20 parts of epoxy resin E-44 or E-51 into a stirring kettle and stir at a low speed of 300 rpm. Then add 8-10 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol (3:1 by volume), 0.5-0.8 parts of defoamer BYK-066N, 1-1.2 parts of dispersant BYK-110, and 0.3-0.4 parts of polyamide wax in sequence. Heat to 40±2°C and stir for 15 minutes until completely dissolved.

[0064] D3. Filler dispersion

[0065] At 50°C, 60-70 parts of pretreated flaky zinc powder, 5-10 parts of phosphate mixture, and 1-2 parts of fumed silica were added to a stirred tank in three batches, with an interval of 5 minutes between each batch. The stirring speed was increased to 800 rpm and the dispersion was continued for 30 minutes. The mixture was then transferred to a sand mill and circulated for grinding until the fineness measured by a scraper fineness meter was ≤50 μm.

[0066] D4. Paint mixing

[0067] At 20-25°C, transfer the ground slurry to a paint mixing kettle, add 3-5 parts of PVB toughening resin and 0.5-0.8 parts of silane coupling agent KH-550, add the remaining solvent to adjust the viscosity, start vacuum degassing at -0.08 MPa, stir at 400 rpm, mix for 20 minutes, slowly add 6-7 parts of cardanol modified amine curing agent NX-2003, reduce the stirring speed to 200 rpm, and continue mixing for 15 minutes;

[0068] D5. Post-processing

[0069] At 20-25°C, the prepared paint was sieved through a 200-mesh sieve to remove impurities, and then filled into a light-proof sealed container and labeled with batch information. According to the above steps, two reagents, D00 and D01, were prepared according to the maximum and minimum components of each component.

[0070] Preparation process of coating:

[0071] Z1. Synthesis of polyether acrylamide

[0072] Jeffamine D-400 was dissolved in tetrachloromethane, and triethylamine was added as an acid binding agent in an amount of 1.2 times the molar amount of acryloyl chloride. Acryloyl chloride was added dropwise to the Jeffamine D-400 solution at 0-5°C until the molar ratio of acryloyl chloride reached 1:1.1. After the addition was completed, the temperature was raised to 25°C and the reaction was carried out for 4 hours. Unreacted acryloyl chloride and solvent were removed by distillation under reduced pressure. The product, polyether acrylamide, was a transparent viscous liquid. SM828 epoxy resin and polyether acrylamide were then mixed in a mass ratio of 1:0.3, and 0.5 wt% triethylbenzylammonium chloride (TEBAC) catalyst of SM828 epoxy resin was added. The mixture was stirred at a constant temperature of 80°C for 6 hours, and then deionized water was added to terminate the reaction. The modified epoxy resin was obtained after vacuum degassing.

[0073] Z2. Mixing and dispersion process

[0074] 70-80 parts of modified epoxy resin and 25-35 parts of polyamide 650# curing agent are mixed at room temperature at a stirring speed of 1,200 r / min for 30 minutes. 8-12 parts of zinc-aluminum composite powder, 80-100 parts of mica iron oxide, and 30-50 parts of glass flakes are added to ensure uniform dispersion of the filler. 1-2 parts of aminosilane KH-550, a silane coupling agent, are also added to promote compatibility between the resin and the filler to obtain a resin matrix.

[0075] Z3. Material Mixing

[0076] Premix 3-5 parts of liquid polysulfide rubber LP-3 with 3-5 parts of PVB resin, pre-react the thiol-epoxy group at 50°C for 1 hour, then blend with 3-5 parts of polyaspartic acid ester and stir evenly. Add to the resin matrix and mix evenly. Then add 0.5-1.5 parts of graphene, 1.2-1.5 parts of BYK-163 dispersant, and 5-8 parts of phosphate compound corrosion inhibitor. Stir at high speed for 1 hour to ensure uniform dispersion.

[0077] Z4. Adjust the properties of the coating

[0078] Add 0.8 parts of anti-settling agent organic bentonite to the above resin matrix to prevent solid filler precipitation, then add 1-1.2 parts of thixotropic agent fumed silica to improve the thixotropy of the coating and improve the coating properties, then add 0.5-0.7 parts of silicone defoamer BYK-066N to eliminate foam generated during the mixing process, stir evenly to allow these ingredients to be fully mixed with the resin matrix, then add 10-15 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol in a volume ratio of 3:1, stir evenly, adjust the viscosity and fluidity of the coating, and then stir comprehensively for 30 minutes;

[0079] Z5.Paint post-processing

[0080] A viscometer is used to test the viscosity of the coating to ensure that it is suitable for coating. A coating experiment is conducted to check the coating's adhesion, corrosion resistance, hardness and other properties. Finally, the prepared coating is stored in a sealed container to avoid volatilization and contamination. When used, coating and curing are carried out according to production requirements. Two reagents, Z00 and Z01, are prepared according to the maximum and minimum components of each component.

[0081] Preparation process of topcoat:

[0082] M1. Reaction of Hydroxylated Acrylic Resin with HDI Trimer

[0083] 50-55 parts of hydroxy acrylic resin and 22-25 parts of HDI trimer curing agent were mixed with 60% solvent (PMA: butyl acetate = 3:1), preheated at 60°C for 10 minutes, and HDI trimer was added dropwise at a rate of 0.5 mL / min under nitrogen protection. The reaction temperature was maintained at 75-80°C and the stirring rate was 300 rpm. After the addition was completed, the temperature was raised to 85°C and the reaction was continued for 2 hours. The NCO group content was monitored until it reached the theoretical value. The mixture was cooled to below 40°C, a dehydrating agent (0.5% molecular sieve) was added, and vacuum degassing was performed for 10 minutes.

[0084] M2. Dispersion process of fillers and functional additives

[0085] 2-3 parts of epoxy tackifying resin Nan Ya E-20 are added to the resin solution obtained in the previous step and mixed evenly. 12-15 parts of aluminum powder and silane coupling agent KH-560 (1.2-1.5 parts) are pre-reacted in ethanol and stirred at 60°C for 2 hours to form a silane coating to reduce the risk of galvanic corrosion. A sand mill with a zirconium bead diameter of 0.8 mm is used to grind to a fineness of ≤15 μm at a speed of 2000 rpm for 2 hours. 0.3-0.5 parts of graphene oxide and 1.2-1.5 parts of dispersant BYK-163 are used in combination, first pre-dispersed in 20% solvent, and then passed through a high shear emulsifier (10000 rpm, 30 min) to form a uniform conductive network. The treated graphene oxide, aluminum powder and glass flakes are sequentially added to the resin solution and stirred evenly. Then, 0.4-0.5 parts of organic bentonite and 0.4-0.5 parts of fumed silica HL-200 are added in sequence.

[0086] M3. Addition of additives

[0087] Add corresponding parts by weight of ultraviolet absorber and defoamer in sequence, stir for 30 minutes to mix evenly, and add the remaining amount of solvent to adjust the viscosity of the solution;

[0088] M4. Filtration and packaging

[0089] Filter through a 200-mesh filter, seal and store in a cool environment at 10-30°C filled with nitrogen. Prepare two reagents, M00 and M01, according to the maximum and minimum components of each component.

[0090] The primer, midcoat and topcoat obtained by the above method were used together to obtain 8 samples.

[0091]

[0092] The performance indicators of the above formula are as follows:

[0093]

[0094] All data must be tested under the following conditions:

[0095] Adhesion: 7 days after the coating is fully cured, 23±2℃ / 50±5%RH environment;

[0096] Cathodic stripping: 3.5% NaCl solution, -1.5 V constant potential, 30 days;

[0097] Salt spray resistance: ISO9227 neutral salt spray, 35℃±2℃

[0098] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0099] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An anti-corrosion coating for submarine pipelines, characterized by: The anti-corrosion coating comprises the following components in parts by mass: Primer: 15-20 parts of epoxy resin E-44 or E-51, 6-7 parts of cardanol modified amine curing agent (NX-2003), 60-70 parts of flaky zinc powder, 0.3-0.4 parts of polyamide wax, 1-2 parts of fumed silica, 5-10 parts of phosphate, 3-5 parts of PVB toughening resin, defoamer BYK-066N, 0.5-0.8 parts of silane coupling agent, 1-1.2 parts of dispersant, 10-12 parts of solvent propylene glycol methyl ether acetate PMA: butanol mixed solution in a volume ratio of 3:1; Medium coating: 70-80 parts of modified epoxy resin, 25-35 parts of polyamide curing agent 650#, 1-2 parts of silane coupling agent, 8-12 parts of zinc-aluminum composite powder, 5-8 parts of phosphate compound corrosion inhibitor, 3-5 parts of liquid polysulfide rubber LP-3, 3-5 parts of PVB toughening resin, 3-5 parts of polyaspartic acid ester, 0.5-1.5 parts of graphene, 0.8-1.0 parts of anti-settling agent organic bentonite, 1-1.2 parts of thixotropic agent fumed silica, 0.5-0.7 parts of silicone defoaming agent BYK-066N, 80-100 parts of mica iron oxide, 30-50 parts of glass flakes, 1.2-1.5 parts of dispersant BYK-163, 10-15 parts of a mixed solution of propylene glycol methyl ether acetate PMA: butanol in a volume ratio of 3:1; Topcoat: 50-55 parts of hydroxy acrylic resin, 22-25 parts of aliphatic isocyanate curing agent HDI trimer, 12-15 parts of flaky aluminum powder, 18-20 parts of glass flakes, 0.3-0.5 parts of graphene oxide, 1.2-1.5 parts of silane coupling agent KH-560, 2-3 parts of epoxy tackifying resin Nan Ya E-20, 1.5-2 parts of ultraviolet absorber, 1-1.2 parts of dispersant, 0.4-0.5 parts of organic bentonite, 0.4-0.5 parts of fumed silica, 0.3-0.4 parts of defoaming agent, 15-18 parts of a mixed solution of solvent propylene glycol methyl ether acetate PMA: butyl acetate in a volume ratio of 3:

1.

2. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The specification of the flaky zinc powder in the primer is 800 mesh.

3. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The silane coupling agent of the midcoat and primer is aminosilane KH-550, the dispersant of the primer is polycarboxylate BYK-110, the phosphate in the primer is a mixture of zinc phosphate and aluminum tripolyphosphate in a mass ratio of 1:1, and the molar ratio of aluminum tripolyphosphate P2O5 / Al2O3 is 3.0-3.

2.

4. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The preparation method of the modified epoxy resin comprises the following steps: polyether amine Jeffamine D-400 reacts with acryloyl chloride to generate polyether acrylamide, which is then subjected to ring-opening and chain-extending with epoxy resin SM828, and a flexible chain segment is introduced to obtain the modified epoxy resin.

5. The anti-corrosion coating for submarine pipeline according to claim 1, characterized in that: The zinc-aluminum composite powder has a Zn / Al ratio of 85 / 15, and the phosphate compound corrosion inhibitor is a compound of zinc phosphate and aluminum tripolyphosphate in a mass ratio of 5:

3.

6. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The flaky aluminum powder used in the topcoat is silane-coated flaky aluminum powder, and the flakes used are glass flakes with a high diameter-to-thickness ratio.

7. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The ultraviolet absorber used in the topcoat is a composite reagent of Tinuvin 1130 and Tinuvin 400 in a mass ratio of 1:

1.

8. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: The dispersant used in the topcoat is a compound of BYK-163 and BYK-2152 in a mass ratio of 1:1, and the defoamer used in the topcoat is a compound of BYK-066N and BYK-024 in a mass ratio of 1:

1.

9. The anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: 0.5 wt % of 3A molecular sieve dehydrating agent is added to a mixed solution of propylene glycol methyl ether acetate (PMA) and butyl acetate (3:1 in volume ratio).

10. The process for preparing an anti-corrosion coating for submarine pipelines according to claim 1, characterized in that: Preparation process of primer: D1. Raw material pretreatment Place 800 mesh flaky zinc powder in an oven at 110°C and dry for 2 hours to remove moisture. Cool to room temperature and weigh zinc phosphate and aluminum tripolyphosphate in a molar ratio of 1:

1. Add the mixture to a high-speed mixer and pre-mix at 800 rpm for 10 minutes to ensure uniform dispersion. D2. Premix Put 15-20 parts of epoxy resin E-44 or E-51 into a stirring kettle and stir at a low speed of 300 rpm. Then add 8-10 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol (3:1 by volume), 0.5-0.8 parts of defoamer BYK-066N, 1-1.2 parts of dispersant BYK-110, and 0.3-0.4 parts of polyamide wax in sequence. Heat to 40±2°C and stir for 15 minutes until completely dissolved. D3. Filler dispersion At 50°C, 60-70 parts of pretreated flaky zinc powder, 5-10 parts of phosphate mixture, and 1-2 parts of fumed silica were added to a stirred tank in three batches, with an interval of 5 minutes between each batch. The stirring speed was increased to 800 rpm and the dispersion was continued for 30 minutes. The mixture was then transferred to a sand mill and circulated for grinding until the fineness measured by a scraper fineness meter was ≤50 μm. D4. Paint mixing At 20-25°C, transfer the ground slurry to a paint mixing kettle, add 3-5 parts of PVB toughening resin and 0.5-0.8 parts of silane coupling agent KH-550, add the remaining solvent to adjust the viscosity, start vacuum degassing at -0.08 MPa, stir at 400 rpm, mix for 20 minutes, slowly add 6-7 parts of cardanol modified amine curing agent NX-2003, reduce the stirring speed to 200 rpm, and continue mixing for 15 minutes; D5. Post-processing At 20-25°C, sieve the prepared paint through a 200-mesh sieve to remove impurities, fill it into a light-proof sealed container, and mark the batch information; Preparation process of coating: Z1. Synthesis of polyether acrylamide Jeffamine D-400 was dissolved in tetrachloromethane, and triethylamine was added as an acid binding agent in an amount of 1.2 times the molar amount of acryloyl chloride. Acryloyl chloride was added dropwise to the Jeffamine D-400 solution at 0-5°C until the molar ratio of acryloyl chloride reached 1:1.

1. After the addition was completed, the temperature was raised to 25°C and the reaction was carried out for 4 hours. Unreacted acryloyl chloride and solvent were removed by distillation under reduced pressure. The product, polyether acrylamide, was a transparent viscous liquid. SM828 epoxy resin and polyether acrylamide were then mixed in a mass ratio of 1:0.3, and 0.5 wt% triethylbenzylammonium chloride (TEBAC) catalyst of SM828 epoxy resin was added. The mixture was stirred at a constant temperature of 80°C for 6 hours, and then deionized water was added to terminate the reaction. The modified epoxy resin was obtained after vacuum degassing. Z2. Mixing and dispersion process 70-80 parts of modified epoxy resin and 25-35 parts of polyamide 650# curing agent are mixed at room temperature at a stirring speed of 1,200 r / min for 30 minutes. 8-12 parts of zinc-aluminum composite powder, 80-100 parts of mica iron oxide, and 30-50 parts of glass flakes are added to ensure uniform dispersion of the filler. 1-2 parts of aminosilane KH-550, a silane coupling agent, are also added to promote compatibility between the resin and the filler to obtain a resin matrix. Z3. Material Mixing Premix 3-5 parts of liquid polysulfide rubber LP-3 with 3-5 parts of PVB resin, pre-react the thiol-epoxy group at 50°C for 1 hour, then blend with 3-5 parts of polyaspartic acid ester and stir evenly. Add to the resin matrix and mix evenly. Then add 0.5-1.5 parts of graphene, 1.2-1.5 parts of BYK-163 dispersant, and 5-8 parts of phosphate compound corrosion inhibitor. Stir at high speed for 1 hour to ensure uniform dispersion. Z4. Adjust the properties of the coating Add 0.8 parts of anti-settling agent organic bentonite to the above resin matrix to prevent solid filler precipitation, then add 1-1.2 parts of thixotropic agent fumed silica to improve the thixotropy of the coating and improve the coating properties, then add 0.5-0.7 parts of silicone defoamer BYK-066N to eliminate foam generated during the mixing process, stir evenly to allow these ingredients to be fully mixed with the resin matrix, then add 10-15 parts of a mixed solution of propylene glycol methyl ether acetate (PMA) and butanol in a volume ratio of 3:1, stir evenly, adjust the viscosity and fluidity of the coating, and then stir comprehensively for 30 minutes; Z5.Paint post-processing Use a viscometer to test the viscosity of the coating to ensure it is suitable for coating. Perform a coating experiment to check the coating's adhesion, corrosion resistance, hardness and other properties. Finally, store the prepared coating in a sealed container to avoid volatilization and contamination. When using, apply and cure according to production requirements. Preparation process of topcoat: M1. Reaction of Hydroxylated Acrylic Resin with HDI Trimer 50-55 parts of hydroxy acrylic resin and 22-25 parts of HDI trimer curing agent were mixed with 60% solvent (PMA: butyl acetate = 3:1), preheated at 60°C for 10 minutes, and HDI trimer was added dropwise at a rate of 0.5 mL / min under nitrogen protection. The reaction temperature was maintained at 75-80°C and the stirring rate was 300 rpm. After the addition was completed, the temperature was raised to 85°C and the reaction was continued for 2 hours. The NCO group content was monitored until it reached the theoretical value. The mixture was cooled to below 40°C, a dehydrating agent (0.5% molecular sieve) was added, and vacuum degassing was performed for 10 minutes. M2. Dispersion process of fillers and functional additives 2-3 parts of epoxy tackifying resin Nan Ya E-20 are added to the resin solution obtained in the previous step and mixed evenly. 12-15 parts of aluminum powder and silane coupling agent KH-560 (1.2-1.5 parts) are pre-reacted in ethanol and stirred at 60°C for 2 hours to form a silane coating to reduce the risk of galvanic corrosion. A sand mill with a zirconium bead diameter of 0.8 mm is used to grind to a fineness of ≤15 μm at a speed of 2000 rpm for 2 hours. 0.3-0.5 parts of graphene oxide and 1.2-1.5 parts of dispersant BYK-163 are used in combination, first pre-dispersed in 20% solvent, and then passed through a high shear emulsifier (10000 rpm, 30 min) to form a uniform conductive network. The treated graphene oxide, aluminum powder and glass flakes are sequentially added to the resin solution and stirred evenly. Then, 0.4-0.5 parts of organic bentonite and 0.4-0.5 parts of fumed silica HL-200 are added in sequence. M3. Addition of additives Add corresponding parts by weight of ultraviolet absorber and defoamer in sequence, stir for 30 minutes to mix evenly, and add the remaining amount of solvent to adjust the viscosity of the solution; M4. Filtration and packaging Filter through a 200-mesh filter, seal and store in a cool place at 10-30℃.

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