Corrosion-resistant and antifouling coating for pipeline and coating method and application of corrosion-resistant and antifouling coating

Abstract

The invention provides a pipeline corrosion-resistant antifouling coating and a coating method and application thereof.The coating comprises a primer layer, a corrosion-resistant layer and an antifouling surface layer, the primer layer is composed of ceramic particles, metal particles and organic silicon modified epoxy resin, and the corrosion-resistant layer comprises a corrosion-resistant additive and an antioxidant; and the antifouling surface layer comprises an ultraviolet light absorber, an antifouling agent and a curing agent. The coating method comprises the steps of surface treatment, primer layer spraying, corrosion-resistant layer spraying, antifouling surface layer spraying and the like, vacuum electroplating, thermal spraying, electrostatic auxiliary spraying and other technologies are adopted, and technological parameters including spraying viscosity, vacuum electroplating pressure, thermal spraying conditions and the like are strictly controlled in each step so as to ensure the coating quality. The pipeline coating has excellent corrosion resistance and antifouling performance, and is suitable for the fields of water conveying pipelines, oil conveying pipelines, chemical engineering pipelines, seawater conveying pipelines and the like.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline coating preparation, and in particular to a pipeline corrosion-resistant and anti-fouling coating, a coating method and an application thereof. Background Art

[0002] In modern industry and daily life, various types of pipelines are widely used, such as water pipelines, oil pipelines, chemical pipelines, and seawater pipelines. These pipelines are in complex environments for a long time and face the dual challenges of corrosion and dirt adhesion. These problems not only shorten the service life of the pipelines, but also may cause safety hazards such as leakage and pollution, posing a threat to the environment and human health.

[0003] At present, traditional pipeline coating technology has many shortcomings in dealing with these problems. On the one hand, in terms of corrosion resistance, some existing coating materials are difficult to function stably and for a long time in harsh chemical environments such as strong acid, strong alkali or high salt. For example, some ordinary paint coatings will fall off and rust in a short time after contacting corrosive chemical raw materials, resulting in pipeline corrosion and perforation, which not only affects the normal use of the pipeline, but also may cause safety accidents and environmental pollution problems. On the other hand, in terms of anti-fouling performance, traditional coatings have limited resistance to dirt. In water pipelines, algae, bacteria and other microorganisms are easy to attach to the inner wall of the pipeline to form biofilms, which not only affect the water quality, but also reduce the water delivery capacity of the pipeline; in oil pipelines, the accumulation of oil and impurities will increase the flow resistance of the pipeline and reduce the delivery efficiency. Moreover, existing anti-fouling coatings often find it difficult to take into account both anti-fouling and other properties at the same time, such as the weak bonding between the coating and the pipeline substrate, uneven coating thickness, and low construction efficiency. These problems limit the wide application and performance of coating technology.

[0004] Therefore, there is an urgent need to develop a new type of corrosion-resistant and anti-fouling coating for pipelines to overcome the shortcomings of existing technologies, improve the corrosion resistance and anti-fouling performance of pipelines, extend the service life of pipelines, reduce maintenance costs, and ensure the safe and efficient operation of pipeline systems. Summary of the invention

[0005] In view of this, the present invention proposes a pipeline corrosion-resistant and anti-fouling coating and a coating method and application thereof to solve the above-mentioned problems.

[0006] The technical solution of the present invention is achieved as follows: a pipeline corrosion-resistant and antifouling coating, the coating is arranged on the inner wall or outer wall of the pipeline, and comprises a primer layer, a corrosion-resistant layer and an antifouling surface layer, the primer comprises the following raw materials in parts by weight: 10-30 parts of ceramic particles, 5-8 parts of metal particles, and 50-80 parts of silicone-modified epoxy resin, the ceramic particles are aluminum oxide or zirconium oxide, and the particle size is 50-100nm, the corrosion-resistant layer comprises the following raw materials in parts by weight: 5-15 parts of corrosion-resistant additives, 3-8 parts of antioxidants, and the antioxidant is titanium dioxide or / and polytetrafluoroethylene; the antifouling surface layer comprises the following raw materials in parts by weight: 2-10 parts of ultraviolet absorbers, 2-4 parts of antifouling agents and 1-3 parts of curing agents, the antifouling agents are diatomaceous earth or activated carbon, and the curing agents include any one or a combination of several of bismuth isooctanoate, ethylenediamine or dibutyltin diacetate.

[0007] Furthermore, the primer comprises the following raw materials in parts by weight: 20 parts of ceramic particles, 7 parts of metal particles, and 70 parts of high molecular polymer matrix; the corrosion-resistant layer comprises the following raw materials in parts by weight: 10 parts of corrosion-resistant additives and 5 parts of antioxidants; the antifouling surface layer comprises the following raw materials in parts by weight: 6 parts of ultraviolet absorbers, 3 parts of antifouling agents, and 2 parts of curing agents.

[0008] Furthermore, the metal particles are zinc, aluminum and magnesium metal elements in a mass ratio of (60-80):(10-30):10, and the grinding particle size is 5-10 μm.

[0009] Furthermore, the organosilicon-modified epoxy resin is prepared by mixing bisphenol A epoxy resin and polydimethylsiloxane in a mass ratio of 70-90:30, adding 25-60% of the total mass of the system toluene and 0.5-1% of the mass of the epoxy resin tetrabutyl titanate, stirring at 300-500 rpm, introducing nitrogen, heating to 100-180° C. and reacting for 2-10 hours, and distilling under reduced pressure to remove toluene to obtain the organosilicon-modified epoxy resin.

[0010] Furthermore, the corrosion-resistant additive is phytic acid and graphene oxide in a mass ratio of (25-58):100.

[0011] Furthermore, the ultraviolet absorber is ultraviolet absorber UV-327, UV-531, UV-234 or UV-327.

[0012] Furthermore, a coating method for a pipeline corrosion-resistant and anti-fouling coating comprises the following steps:

[0013] S1. Surface treatment: pre-treat the pipe surface to remove oil, rust and other impurities, and then perform sandblasting to make the surface roughness reach 2.5-5.0μm;

[0014] S2. Spraying primer layer: disperse the primer raw material at high speed, add 70-90% ethanol solution by mass fraction and mix evenly, the mass volume ratio of primer raw material and ethanol solution g / mL is 1-3:1, and spray it on the pipeline surface by vacuum plating. The spraying viscosity is 8.5-10.0s, the pressure of vacuum plating is 0.2-0.25MPa, and a primer layer is formed with a thickness of 10-30μm. Dry it by infrared radiation, control the radiation temperature at 60-80℃, and the drying time is 1-3h;

[0015] S3, spraying corrosion-resistant layer: mix corrosion-resistant additives and antioxidants, and apply magnetic field with magnetic field strength controlled at 0.1-0.5T, stirring speed at 800-1000rpm, stirring for 30-40min, and then use thermal spraying process to spray on the surface of primer layer to form corrosion-resistant layer with thickness of 50-100μm, put the pipeline into vacuum drying oven, control vacuum degree at 10-100Pa, temperature at 80-100℃, drying time 2-4h, remove solvent and moisture in the coating;

[0016] S4. Spraying antifouling surface layer: adding ultraviolet absorber, antifouling agent and curing agent to turpentine, and carrying out ultrasonic-assisted high-speed stirring for 20-30 minutes. The ultrasonic frequency is 20-40kHz, and the power is 200-500W. The mass ratio of the corrosion-resistant layer raw material to turpentine is 4-6:1. The antifouling surface layer raw material is coated on the corrosion-resistant layer by combining electrostatic assistance and thermal spraying process to form an antifouling surface layer with a thickness of 20-50μm. After coating, it is irradiated with a 300-400nm ultraviolet lamp at 20-40℃ for 1-3h for curing.

[0017] Furthermore, the thermal spraying process of S3 and S4 is arc spraying, with an arc pressure of 20-30V, a current of 180-350A, and a temperature of 100-150°C.

[0018] Furthermore, the S4 is to first turn on the electrostatic generator, adjust the voltage to 20-60 kV and the current to 0.5-2 mA to charge the paint particles, and then heat the paint to 100-150° C. by thermal spraying before spraying.

[0019] Furthermore, the pipeline corrosion-resistant and anti-fouling coating is used in water pipelines, oil pipelines, chemical pipelines or seawater pipelines.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The pipeline coating of the present invention realizes comprehensive protection of the pipeline by setting a three-layer structure combination of a primer layer, a corrosion-resistant layer and an antifouling surface layer. The primer layer enhances the bonding force between the coating and the pipeline substrate, providing a solid base for the subsequent coating; the corrosion-resistant layer utilizes the synergistic effect of efficient corrosion-resistant additives and antioxidants to effectively resist the erosion of various corrosive media, greatly slow down the corrosion rate, significantly improve the corrosion resistance of the pipeline, and significantly extend the service life of the pipeline in harsh environments; the antifouling surface layer is added with a curing agent to quickly solidify the antifouling surface layer, and the antifouling and self-cleaning properties of the coating are further improved by photocatalysis; in the preparation process, the parameters of each step are precisely controlled to ensure that the coating quality is stable and uniform. Surface sandblasting enhances adhesion, vacuum plating, arc spraying and other processes make the coating uniform and dense, applying a magnetic field promotes uniform mixing of the raw materials of the corrosion-resistant layer, and electrostatic assisted thermal spraying makes the raw materials of the antifouling surface layer more evenly distributed and has a good curing effect, and the overall process is simple to operate and highly operable, suitable for large-scale industrial production. DETAILED DESCRIPTION

[0022] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0023] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0024] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0025] Example 1

[0026] A pipeline corrosion-resistant and anti-fouling coating, the coating is arranged on the inner wall or outer wall of the pipeline, and comprises a primer layer, a corrosion-resistant layer and an anti-fouling surface layer;

[0027] The primer comprises the following raw materials in parts by weight: 10 parts of ceramic particles, 5 parts of metal particles, and 50 parts of organosilicon-modified epoxy resin, wherein the ceramic particles are aluminum oxide with a particle size of 50 nm; the metal particles are zinc, aluminum and magnesium metal elements with a mass ratio of 60:10:10, and the grinding particle size is 5 μm; the organosilicon-modified epoxy resin is specifically prepared by mixing bisphenol A epoxy resin and polydimethylsiloxane in a mass ratio of 70:30, and then adding 25% of toluene of the total mass of the system and 0.5% of tetrabutyl titanate of the mass of the epoxy resin, stirring at 300 rpm, introducing nitrogen, heating to 100° C. for reaction for 2 hours, and distilling under reduced pressure to remove toluene to obtain the organosilicon-modified epoxy resin;

[0028] The corrosion-resistant layer comprises the following raw materials in parts by weight: 5 parts of corrosion-resistant additives and 3 parts of antioxidants, wherein the corrosion-resistant additives are phytic acid and graphene oxide in a mass ratio of 25:100, and the antioxidant is titanium dioxide;

[0029] The antifouling surface layer comprises the following raw materials in parts by weight: 2 parts of ultraviolet absorber, 2 parts of antifouling agent and 1 part of curing agent, the ultraviolet absorber is ultraviolet absorber UV-327, the antifouling agent is diatomaceous earth, and the curing agent is bismuth isooctanoate.

[0030] Example 2

[0031] A pipeline corrosion-resistant and anti-fouling coating, the coating is arranged on the inner wall or outer wall of the pipeline, and comprises a primer layer, a corrosion-resistant layer and an anti-fouling surface layer;

[0032] The primer comprises the following raw materials in parts by weight: 30 parts of ceramic particles, 8 parts of metal particles, and 80 parts of organosilicon-modified epoxy resin, wherein the ceramic particles are zirconium oxide with a particle size of 100 nm; the metal particles are zinc, aluminum and magnesium metal elements with a mass ratio of 80:30:10, and the grinding particle size is 10 μm; the organosilicon-modified epoxy resin is specifically prepared by mixing bisphenol A epoxy resin and polydimethylsiloxane in a mass ratio of 90:30, and then adding 60% of the total mass of toluene and 1% of tetrabutyl titanate by mass of the epoxy resin, stirring at 500 rpm, introducing nitrogen, heating to 180° C. for reaction for 10 hours, and distilling under reduced pressure to remove toluene to obtain the organosilicon-modified epoxy resin;

[0033] The corrosion-resistant layer comprises the following raw materials in parts by weight: 15 parts of corrosion-resistant additives and 8 parts of antioxidants, wherein the corrosion-resistant additives are phytic acid and graphene oxide in a mass ratio of 58:100, and the antioxidant is titanium dioxide;

[0034] The antifouling surface layer comprises the following raw materials in parts by weight: 10 parts of ultraviolet absorber, 4 parts of antifouling agent and 3 parts of curing agent, the ultraviolet absorber is ultraviolet absorber UV-531, the antifouling agent is activated carbon, and the curing agent is ethylenediamine.

[0035] Example 3

[0036] A pipeline corrosion-resistant and anti-fouling coating, the coating is arranged on the inner wall or outer wall of the pipeline, and comprises a primer layer, a corrosion-resistant layer and an anti-fouling surface layer;

[0037] The primer comprises the following raw materials in parts by weight: 20 parts of ceramic particles, 7 parts of metal particles, and 70 parts of a high molecular polymer matrix, wherein the ceramic particles are zirconium oxide with a particle size of 80 nm; the metal particles are zinc, aluminum, and magnesium metal elements in a mass ratio of 70:20:10, and the grinding particle size is 8 μm; the organosilicon-modified epoxy resin is prepared by mixing bisphenol A epoxy resin and polydimethylsiloxane in a mass ratio of 80:30, and then adding 45% of toluene of the total mass of the system and 0.8% of tetrabutyl titanate of the mass of the epoxy resin, stirring at 400 rpm, introducing nitrogen, heating to 150° C. for reaction for 6 hours, and performing reduced pressure distillation to remove toluene to obtain the organosilicon-modified epoxy resin;

[0038] The corrosion-resistant layer comprises the following raw materials in parts by weight: 10 parts of corrosion-resistant additives and 5 parts of antioxidants, wherein the corrosion-resistant additives are phytic acid and graphene oxide in a mass ratio of 35:100, and the antioxidant is titanium dioxide;

[0039] The antifouling surface layer comprises the following raw materials in parts by weight: 6 parts of ultraviolet absorber, 3 parts of antifouling agent and 2 parts of curing agent, the ultraviolet absorber is ultraviolet absorber UV-327, the antifouling agent is diatomaceous earth, and the curing agent is bismuth isooctanoate and ethylenediamine in a mass ratio of 1:2;

[0040] The above-mentioned embodiments 1-3 adopt the following coating method:

[0041] S1. Surface treatment: pre-treat the pipe surface to remove oil, rust and other impurities, and then perform sandblasting to make the surface roughness reach 4.0μm;

[0042] S2. Spraying primer layer: disperse the primer raw material at high speed, add 80% ethanol solution by mass fraction and mix evenly, the mass volume ratio of primer raw material and ethanol solution is 2:1 g / mL, and spray it on the pipeline surface by vacuum plating. The spraying viscosity is 9.0s, the pressure of vacuum plating is 0.23MPa, and a primer layer is formed with a thickness of 20μm. Dry it by infrared radiation, control the radiation temperature at 70℃, and dry it for 2h;

[0043] S3, spraying corrosion-resistant layer: mix corrosion-resistant additives and antioxidants, and apply magnetic field with magnetic field intensity controlled at 0.3T, stirring speed at 900rpm, stirring for 35min, and then use arc spraying on the surface of primer layer with arc pressure of 25V, current of 250A, temperature of 120℃, forming corrosion-resistant layer with thickness of 80μm, put the pipeline into vacuum drying oven, control vacuum degree at 60Pa, temperature at 90℃, drying time for 3h, remove solvent and moisture in coating;

[0044] S4. Spraying antifouling surface layer: adding ultraviolet absorber, antifouling agent and curing agent to turpentine, carry out ultrasonic-assisted high-speed stirring for 25 minutes, the ultrasonic frequency is 30kHz, the power is 350W, the mass ratio of the corrosion-resistant layer raw material to turpentine is 5:1, and the antifouling surface layer raw material is coated on the corrosion-resistant layer by combining electrostatic assistance and arc spraying process. The arc pressure is 25V, the current is 250A, and the temperature is 120℃ to form an antifouling surface layer with a thickness of 35μm. After coating, it is cured by irradiation with a 350nm ultraviolet lamp at 30℃ for 2h.

[0045] Comparative Example 1

[0046] The difference between this comparative example and Example 3 is that the primer raw material does not contain metal particles.

[0047] Comparative Example 2

[0048] The difference between this comparative example and Example 3 is that the epoxy resin in the primer raw material is not modified.

[0049] Comparative Example 3

[0050] The difference between this comparative example and Example 3 is that the corrosion-resistant layer raw material does not contain corrosion-resistant additives.

[0051] Comparative Example 4

[0052] The difference between this comparative example and Example 3 is that the antifouling surface layer raw material does not contain a curing agent.

[0053] Comparative Example 5

[0054] The difference between this comparative example and Example 3 is that in the coating method, no magnetic field is applied during the mixing of the corrosion-resistant layer raw materials in step S3. Specifically, the corrosion-resistant additives and antioxidants are mixed, the stirring speed is 900 rpm, and the stirring is carried out for 35 minutes. Then, electric arc spraying is used on the surface of the primer layer. The arc pressure is 25 V, the current is 250 A, and the temperature is 120°C to form a corrosion-resistant layer with a thickness of 80 μm. The pipeline is placed in a vacuum drying oven, the vacuum degree is controlled at 60 Pa, the temperature is at 90°C, and the drying time is 3 hours to remove the solvent and moisture in the coating.

[0055] Comparative Example 6

[0056] The difference between this comparative example and Example 3 is that in the coating method, step S4 only uses an arc spraying process to coat the antifouling surface layer raw material on the corrosion-resistant layer. The arc pressure is 25V, the current is 250A, and the temperature is 120°C to form an antifouling surface layer with a thickness of 35μm. After coating, a 350nm ultraviolet lamp is used for irradiation at 30°C for 2h for curing.

[0057] Comparative Example 7

[0058] The difference between this comparative example and Example 3 is that in the coating method, no ultraviolet irradiation is used after the coating is completed in step S4, and specifically, the coating is dried and cured at 80° C. after the coating is completed.

[0059] Test Example 1-Corrosion Resistance Test

[0060] 1. Salt spray test

[0061] 1. Test method: According to the standard ASTMB117, place the coated pipe specimen in a salt spray test chamber. The salt spray solution is a 5% sodium chloride solution, and the pH value of the solution must be controlled between 6.5-7.2. The temperature in the test chamber is maintained at 35℃±2℃, and the salt spray deposition rate is 1-2mL / (80cm 2 ·h). Continuous spraying for 1000 hours.

[0062] 2. Performance evaluation: According to ASTMD714 standard, the degree of damage to the coating is rated.

[0063] 2. Immersion test

[0064] 1. Test method: Select 5% hydrochloric acid solution as the corrosive medium, and completely immerse the coated pipe specimen in the solution. The solution temperature is (25℃±5℃) and the immersion time is 60 days.

[0065] 2. Performance evaluation: Take out the test pieces regularly and observe the changes in the appearance of the coating. By measuring the changes in performance indicators such as adhesion and hardness of the coating, the corrosion resistance of the coating can be comprehensively evaluated.

[0066] 3. Electrochemical test

[0067] 1. Test method: Polarization curve test and electrochemical impedance spectroscopy (EIS) test are used. The anode current density (A / cm 2 ) is used to measure the degree of coating corrosion rate. An AC sine wave signal with an amplitude of 20mV is used, and the number of data points collected at each frequency point is not less than 10, and the impedance value in the low frequency area is measured.

[0068] 2. Performance evaluation: The smaller the corrosion current density, the better the corrosion resistance of the coating; the higher the measured impedance value, the stronger the corrosion resistance of the coating.

[0069] Test results:

[0070] Table 1:

[0071]

[0072]

[0073] According to the above test results, the coatings of Examples 1-3 are significantly better than the coatings of Comparative Examples 1-7 in terms of corrosion resistance; they can maintain good stability and adhesion, and effectively prevent the solution from corroding the pipeline. The lower corrosion current density means that the coating can effectively inhibit the corrosion reaction, thereby extending the service life of the pipeline; and the higher low-frequency impedance value indicates that the coating of the present invention has good insulation performance and protection ability, and can effectively prevent the penetration of corrosive media.

[0074] Test Example 2- Antifouling Performance Test

[0075] 1. Static hanging test

[0076] 1. Test method: Cut a number of 5 cm × 5 cm test pieces from the coated pipes of Examples 1-3 and Comparative Examples 1-6 and hang them in a sewage solution medium containing algae, bacteria and other microorganisms to simulate the actual use environment of the pipes. The hanging time is 8 weeks.

[0077] 2. Observation and measurement: Take out the test piece, gently rinse the surface, and remove loosely attached dirt. Use an optical microscope to observe the type, distribution, and adhesion morphology of dirt on the coating surface. Use an electronic balance to measure the weight of the test piece and calculate the amount of dirt attached; at the same time, use image analysis software to calculate the percentage of dirt coverage area.

[0078] Dirt adhesion amount = weight after test - weight before test.

[0079] 2. Dynamic simulation test

[0080] 1. Test device construction: Build a simulated pipeline system, including liquid storage tanks, circulation pumps, pipelines, flow meters and other equipment;

[0081] 2. Medium preparation: According to the actual use environment, configure a simulated urban drainage pipe and add mud, grease, microorganisms, etc. to the water; simulate an industrial circulating water pipe and add corrosion products, scale and other components.

[0082] 3. Specimen installation: Install the coated pipe specimen in the test section of the simulated pipeline system to ensure that the specimen is tightly connected to the pipeline without leakage.

[0083] 4. Operation parameter setting: Start the circulation pump to make the simulated liquid circulate in the pipeline at a flow rate of 3m / s. The operation time is 3 months. During this period, collect simulated liquid samples regularly to analyze the changes in their composition.

[0084] 5. Monitoring and evaluation: Use a high-definition camera to capture the dirt adhesion on the surface of the test piece and record the distribution location and degree of the dirt. After the test, disassemble the test piece and use a scanning electron microscope (SEM) and energy spectrum analysis (EDS) to analyze the microstructure and composition of the dirt. At the same time, measure the total weight of the dirt on the surface of the test piece by weighing, and calculate the average amount of dirt adhesion at different parts of the pipeline.

[0085] 3. Contact angle test

[0086] 1. Test sample preparation: Cut a flat coating sample from the pipe with a size of 1cm×1cm, and prepare at least 5 samples. Fix the sample on the sample table and ensure that the surface is clean and dry.

[0087] 2. Test process: Add 3-5 drops of 40% oily aqueous solution to each sample surface, with a droplet volume of 10 μL. Use a contact angle meter to measure the contact angle between the droplet and the coating surface. Measure each droplet 3 times, and take the average value as the contact angle of that point. Repeat the above operation at different locations of the sample, measure at least 5 points, and finally calculate the average contact angle.

[0088] 4. Test Results

[0089] Table 2:

[0090]

[0091]

[0092]

[0093] According to the above test results, the amount of dirt adhesion and coverage area of ​​the embodiment group are significantly lower than those of the comparative example. This shows that the coating of the embodiment has better anti-fouling performance and can effectively prevent the adhesion and growth of dirt on its surface. The dirt distribution in the pipeline test section of the embodiment group is more uniform, the average adhesion amount is lower, and the degree of coating wear is less. This shows that the coating of the embodiment group can still maintain good anti-fouling performance and wear resistance in a dynamic flow environment. The contact angle of the embodiment group is larger, indicating that the wettability of the coating surface is poor and it is more difficult for dirt to adhere to its surface.

[0094] In summary, Example 3 has the best corrosion resistance and antifouling effect; compared with Comparative Example 1, Example 3 adds metal particles to the primer to play an electrochemical protection role. The metal particles as anodes will be corroded first and undergo oxidation reactions themselves, while the pipeline substrate is protected as a cathode, thereby avoiding corrosion of the pipeline substrate. At the same time, when the metal particles in the spraying process hit the surface of the pipeline substrate at high speed, they will be embedded in the tiny pits and gaps on the substrate surface, forming a good mechanical bite with the surface of the pipeline substrate, forming a solid bottom layer, thereby playing a certain physical isolation role for the corrosive medium.

[0095] Compared with Comparative Example 2, the introduction of polydimethylsiloxane in Example 3 improves the wettability of the epoxy resin, enabling it to better contact the pipeline surface and the ceramic particles and metal particles in the primer, further enhancing the bonding force between the primer and the pipeline, thereby improving the adhesion of the coating, ensuring the stability of the coating system on the pipeline surface, and not easy to fall off. Polydimethylsiloxane has low surface energy and good chemical stability, can effectively block the intrusion of corrosive media, and reduce the contact between moisture, oxygen and other corrosive substances and the pipeline substrate. At the same time, the continuous polymer film formed by the silicone-modified epoxy resin can isolate the metal particles in the primer, slow down the corrosion rate of the metal, improve the corrosion resistance of the entire primer layer, and thus enhance the protection ability of the entire coating system to the pipeline.

[0096] Example 3 Compared with Comparative Example 3, the corrosion-resistant additive composed of phytic acid and graphene oxide can synergistically enhance the corrosion resistance. The graphene oxide surface contains rich functional groups such as hydroxyl and carboxyl, which can react chemically with high molecular polymer matrices such as epoxy resin to form chemical bonding, thereby enhancing the bonding force between the corrosion-resistant layer and the primer layer. At the same time, phytic acid can also interact with metal particles and ceramic particles, and through chemical bonds or physical adsorption, the interface between the primer layer and the corrosion-resistant layer is made tighter, thereby improving the structural stability of the entire coating system. This good bonding force helps to ensure that during long-term use, the coating will not have problems such as stratification and peeling, thereby ensuring that the corrosion resistance of the coating is lasting and effective; at the same time, it synergizes with the antioxidant in the system, and graphene oxide acts as an electron acceptor to capture the active oxygen species generated by the coating during use. Phytic acid inhibits the generation and propagation of free radicals, and acts together with titanium dioxide to form an antioxidant system, effectively preventing the performance degradation of the coating caused by oxidation, extending the service life of the coating, and maintaining the corrosion resistance of the coating.

[0097] Compared with Comparative Example 4, in the curing agent composed of bismuth isooctanoate and ethylenediamine, bismuth isooctanoate can reduce the activation energy of the curing reaction, so that the coating can reach a higher degree of curing in a relatively short time, and the amino group in ethylenediamine can chemically react with the epoxy group in the epoxy resin to form a cross-linked polymer with a three-dimensional network structure. By using it in combination with bismuth isooctanoate, ethylenediamine can more fully participate in the cross-linking reaction, and can form a strong chemical bond between the coating and the pipeline surface and between the coatings, thereby significantly improving the adhesion of the coating. At the same time, the dense cross-linked network structure formed can effectively prevent the deposition and adhesion of dirt.

[0098] Compared with Example 5, applying a magnetic field to the mixing process of the corrosion-resistant layer raw materials can make the raw materials more fully dispersed and contacted, so that the corrosion-resistant layer can form a tighter and more stable interface when combined with the primer layer.

[0099] Compared with Example 6, Example 3 can quickly and evenly distribute the coating on the pipe surface by electrostatic assisted spraying, while arc spraying can form a coating of a certain thickness in a short time. The combination of the two makes the antifouling surface layer not only have good antifouling performance, but also have excellent adhesion, corrosion resistance, wear resistance and other comprehensive properties.

[0100] Compared with Comparative Example 7, Example 3 uses ultraviolet irradiation after coating to connect the molecular chains in the coating to form a tight network structure, which effectively accelerates the curing, while better protecting the coating from damage by ultraviolet rays and reducing problems such as coating aging, fading, and powdering caused by ultraviolet radiation.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pipeline corrosion-resistant and anti-fouling coating, characterized in that: The coating is arranged on the inner wall or outer wall of the pipeline, and comprises a primer layer, a corrosion-resistant layer and an antifouling surface layer. The primer comprises the following raw materials in parts by weight: 10-30 parts of ceramic particles, 5-8 parts of metal particles, and 50-80 parts of silicone-modified epoxy resin. The ceramic particles are aluminum oxide or zirconium oxide, and the particle size is 50-100 nm. The corrosion-resistant layer comprises the following raw materials in parts by weight: 5-15 parts of corrosion-resistant additives and 3-8 parts of antioxidants. The antioxidant is titanium dioxide and / or polytetrafluoroethylene. The antifouling surface layer comprises the following raw materials in parts by weight: 2-10 parts of ultraviolet absorbers, 2-4 parts of antifouling agents and 1-3 parts of curing agents. The antifouling agents are diatomaceous earth or activated carbon. The curing agents include any one or a combination of several of bismuth isooctanoate, ethylenediamine or dibutyltin diacetate.

2. A pipeline corrosion-resistant and anti-fouling coating according to claim 1, characterized in that: The primer comprises the following raw materials in parts by weight: 20 parts of ceramic particles, 7 parts of metal particles, and 70 parts of high molecular polymer matrix; the corrosion-resistant layer comprises the following raw materials in parts by weight: 10 parts of corrosion-resistant additives and 5 parts of antioxidants; the antifouling surface layer comprises the following raw materials in parts by weight: 6 parts of ultraviolet absorbers, 3 parts of antifouling agents, and 2 parts of curing agents.

3. The corrosion-resistant and anti-fouling coating for pipelines according to claim 1, characterized in that: The metal particles are zinc, aluminum and magnesium metal elements in a mass ratio of (60-80):(10-30):10, and the grinding particle size is 5-10 μm.

4. The pipeline corrosion-resistant and anti-fouling coating according to claim 1, characterized in that: The organosilicon-modified epoxy resin is prepared by mixing bisphenol A epoxy resin and polydimethylsiloxane in a mass ratio of 70-90:30, adding 25-60% of toluene by mass of the system and 0.5-1% of tetrabutyl titanate by mass of the epoxy resin, stirring at 300-500 rpm, introducing nitrogen, heating to 100-180° C., reacting for 2-10 hours, and performing reduced pressure distillation to remove toluene to obtain the organosilicon-modified epoxy resin.

5. The pipeline corrosion-resistant and anti-fouling coating according to claim 1, characterized in that: The corrosion-resistant additive is phytic acid and graphene oxide in a mass ratio of (25-58):

100.

6. The corrosion-resistant and anti-fouling coating for pipelines according to claim 1, characterized in that: The ultraviolet absorber is ultraviolet absorber UV-327, UV-531, UV-234 or UV-327.

7. A coating method for a pipeline corrosion-resistant and antifouling coating as claimed in claim 1, characterized in that: The following steps are involved: S1. Surface treatment: pre-treat the pipe surface to remove oil, rust and other impurities, and then perform sandblasting to make the surface roughness reach 2.5-5.0μm; S2. Spraying primer layer: disperse the primer raw material at high speed, add 70-90% ethanol solution by mass fraction and mix evenly, the mass volume ratio of primer raw material and ethanol solution g / mL is 1-3:1, and spray it on the pipeline surface by vacuum plating. The spraying viscosity is 8.5-10.0s, the pressure of vacuum plating is 0.2-0.25MPa, and a primer layer is formed with a thickness of 10-30μm. Dry it by infrared radiation, control the radiation temperature at 60-80℃, and the drying time is 1-3h; S3, spraying corrosion-resistant layer: mix corrosion-resistant additives and antioxidants, and apply magnetic field with magnetic field strength controlled at 0.1-0.5T, stirring speed at 800-1000rpm, stirring for 30-40min, and then use thermal spraying process to spray on the surface of primer layer to form corrosion-resistant layer with thickness of 50-100μm, put the pipeline into vacuum drying oven, control vacuum degree at 10-100Pa, temperature at 80-100℃, drying time 2-4h, remove solvent and moisture in the coating; S4. Spraying antifouling surface layer: adding ultraviolet absorber, antifouling agent and curing agent to turpentine, and carrying out ultrasonic-assisted high-speed stirring for 20-30 minutes. The ultrasonic frequency is 20-40kHz, and the power is 200-500W. The mass ratio of the corrosion-resistant layer raw material to turpentine is 4-6:

1. The antifouling surface layer raw material is coated on the corrosion-resistant layer by combining electrostatic assistance and thermal spraying process to form an antifouling surface layer with a thickness of 20-50μm. After coating, it is irradiated with a 300-400nm ultraviolet lamp at 20-40℃ for 1-3h for curing.

8. A coating method for a pipeline corrosion-resistant and antifouling coating as claimed in claim 7, characterized in that: The thermal spraying process of S3 and S4 is arc spraying, with an arc pressure of 20-30V, a current of 180-350A, and a temperature of 100-150°C.

9. A coating method for a pipeline corrosion-resistant and antifouling coating as claimed in claim 7, characterized in that: The S4 is to first turn on the electrostatic generator, adjust the voltage to 20-60 kV and the current to 0.5-2 mA to charge the paint particles, and then heat the paint to 100-150° C. by thermal spraying before spraying.

10. Use of the pipeline corrosion-resistant and antifouling coating according to any one of claims 1 to 6 in a water pipeline, an oil pipeline, a chemical pipeline or a seawater pipeline.

Images