Steel pipe anti-corrosion coating and preparation method thereof

Abstract

The invention discloses a steel pipe anti-corrosion coating and a preparation method thereof, and relates to the technical field of coatings. The steel pipe anti-corrosion coating is prepared from functionalized hexagonal boron nitride tannic acid silicon dioxide hybrid particles, high-performance modified waterproof acrylic resin emulsion, titanium dioxide, a BYK-190 dispersing agent, a BYK-011 defoaming agent, a BYK-358N flatting agent, hydroxymethyl cellulose and deionized water. Functional hexagonal boron nitride tannic acid silicon dioxide hybrid particles are uniformly embedded and dispersed in a high-performance modified acrylic resin emulsion matrix to serve as a composite reinforcing main body, and in the curing and film forming process, fluorine-containing chain segments in the hybrid particles and resin spontaneously migrate to an interface of a coating and air and are enriched, so that the coating is formed. The nano-scale low-surface-energy compact outer layer is formed, the hardness of the coating and the adhesive force of the coating to the steel pipe are enhanced, and the corrosion resistance of the coating is remarkably improved by constructing multiple protective barriers integrating active repulsion, physical barrier, chemical inertness and interface strengthening.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coatings, and particularly relates to a steel pipe anti-corrosion coating and a preparation method thereof. BACKGROUND

[0002] Steel is the most widely used and largest used engineering structure material at present, and steel corrosion can seriously affect the safety and durability of the material, causing equipment performance degradation, failure, reduction of equipment cycle life and other problems. In order to eliminate the safety hazards caused by metal corrosion or reduce the economic losses caused by metal corrosion, certain protective measures need to be taken. Common anti-corrosion strategies include coating protection, electroplating, surface treatment, anodic protection, cathodic protection and corrosion inhibitor, etc. Among these anti-corrosion methods, the application of coating is a simple and cost-effective method to protect steel from corrosion.

[0003] The existing technology mainly has the following problems:

[0004] Single coating film is difficult to achieve good adhesion effect and corrosion resistance on the steel pipe substrate after film formation, and cannot meet the corrosion prevention requirements. SUMMARY

[0005] In view of the above problems, the present application provides a steel pipe anti-corrosion coating, which comprises the following components by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 3-6 parts, high-performance modified water-resistant acrylic resin emulsion 50-60 parts, titanium white 15-20 parts, BYK-190 dispersant 0.3-0.5 parts, BYK-011 defoamer 0.2-0.4 parts, BYK-358N leveling agent 0.2-0.4 parts, hydroxymethyl cellulose 0.3-0.5 parts, and deionized water 15-20 parts.

[0006] The functionalized hexagonal boron nitride tannic acid silica hybrid particles are prepared from the following components by weight: hexagonal boron nitride 8-10 parts, tannic acid 3-5 parts, tetraethyl orthosilicate 2-6 parts, and octadecyl trimethoxysilane 8.8-17.6 parts.

[0007] The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles specifically comprises the following steps:

[0008] (1) 0.8-1.0 g of hexagonal boron nitride is first dispersed in 100-200 mL of deionized water by ultrasonic, then added to 50 mL of 0.2-0.4% sodium hydroxide solution with pH 8.5, then tannic acid is added, under the conditions of 200-300 rpm magnetic stirring and 50-60 °C water bath, the reaction is carried out for 2-3 h, then centrifugation, the precipitate is washed with anhydrous ethanol and deionized water in turn, until the washing liquid is neutral and there is no yellow or brown color, the coating of tannic acid on hexagonal boron nitride improves the compatibility and binding force of hexagonal boron nitride with the resin matrix, the uniformly dispersed rigid hexagonal boron nitride sheet layer not only can hinder the slip and deformation of the resin molecular chain, improve the hardness of the coating after film forming, but also can be arranged in parallel in the coating, forming a zigzag physical barrier, greatly extending the penetration path of corrosion media such as water, oxygen, chloride ions to the surface of the steel pipe, thus producing a synergistic enhancement effect, obtaining wet state hexagonal boron nitride@tannic acid precipitate;

[0009] (2) The wet state hexagonal boron nitride@tannic acid precipitate in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, at the same time, 100 mL of anhydrous ethanol, 20 mL of deionized water and 3-5 mL of 25-28% ammonia water are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, under the conditions of 200-300 rpm magnetic stirring and 30 °C, tetraethyl orthosilicate is added using a constant pressure dropping funnel, the dropping speed is controlled to be 1-2 s per drop, after the addition is completed, the reaction is continued under the same conditions for 12-24 h, centrifugation, the precipitate is washed with anhydrous ethanol and deionized water in turn for 3-5 times, dried in a vacuum oven at 60-80 °C, and ground, in this process, the construction of the silica shell layer not only can form strong hydrogen bonds with the metal hydroxyl groups on the surface of the steel pipe, but also can form a firm hydrogen bond network with the resin matrix, also increases the interface roughness, which is beneficial to the effective mechanical interlocking effect with the resin matrix, thus improving the interface compatibility of hexagonal boron nitride with the matrix and improving the overall adhesion, at the same time, this core-shell structure of hexagonal boron nitride and silica forms a rigid hybrid reinforcing unit, when they are uniformly dispersed in the relatively soft polymer matrix, they can effectively resist external stress and deformation, improve the hardness of the coating, and the silica shell layer itself has a dense structure, which can effectively block the penetration of water, oxygen and corrosive ions, its cooperation with the flaky hexagonal boron nitride core makes the diffusion path of corrosion media in the coating more tortuous and longer, by constructing a dense barrier and stable interface, the corrosion resistance is improved, obtaining hexagonal boron nitride@tannic acid silica hybrid particles;

[0010] (3) the hexagonal boron nitride@tannic acid silica hybrid particles in step (2) are ultrasonically dispersed in 200-300 mL of anhydrous ethanol, then octadecyltrimethoxysilane is added, and the reaction is carried out under the conditions of 200-300 rpm magnetic stirring and 50-60°C water bath for 8-12 h; after the reaction is completed, centrifugation is performed, the precipitate is washed with anhydrous ethanol and deionized water in sequence until the washing liquid is neutral, and finally, the precipitate is dried in a vacuum oven at 60-80°C, ground, and the octadecyltrimethoxysilane is grafted on the surface of the hexagonal boron nitride@tannic acid silica hybrid particles through a covalent bond; the long-chain octadecyl groups of the outwardly extending low-surface-energy groups are densely arranged, so that water molecules cannot wet the surface, the invasion of the corrosion medium is reduced from the source, the damage of water to the coating-substrate interface is also reduced, thereby reducing the risk of blistering and peeling of the coating after film formation, and the firm adhesion established by the tannic acid and the silica is protected, and the functionalized hexagonal boron nitride@tannic acid silica hybrid particles are obtained;

[0011] Preferably, in step (1), the addition amount of tannic acid is 0.3-0.5 g; the tannic acid can firmly fix the coating on the surface of the steel pipe by virtue of strong metal chelation, and further provides a synergistic guarantee for corrosion resistance by enhancing adhesion and improving filler dispersibility;

[0012] Preferably, in step (2), the addition amount of tetraethyl orthosilicate is 0.2-0.6 mL; under the catalysis of ammonia water, the tetraethyl orthosilicate is hydrolyzed and condensed to form silica, and is deposited and grown on the surface of the hexagonal boron nitride@tannic acid with rich hydroxyl groups, and finally forms a uniform and complete shell layer;

[0013] Preferably, in step (3), the addition amount of octadecyltrimethoxysilane is 1.0-2.0 mL; the long alkyl chain introduced by the octadecyltrimethoxysilane has excellent compatibility with the resin matrix, which is beneficial to the uniform dispersion of the hybrid particles in the resin, and ensures the uniformity and stability of the hardness of the coating.

[0014] The application also provides a preparation method of the steel pipe corrosion-resistant coating.

[0015] S1, 100.0-110.0 g castor oil, 20.0-30.0 g trimethylolpropane are added to the reactor, dehydrated under nitrogen protection at 120℃ for 20-30 min, then cooled to 80℃, 8.0-10.0 g dimethylol propionic acid and 25.0-30.0 g acetone are added, stirred to dissolve, then slowly drop hexafluorohexane diisocyanate and 0.1 g dibutyltin dilaurate catalyst, react at 80℃ until the NCO characteristic absorption peak disappears, remove acetone by distillation under reduced pressure, this process synthesizes a fluorinated polyurethane oligomer with flexibility, crosslinking potential, water dispersibility and top surface performance, which as the backbone structure of the subsequent resin system, lays the foundation for the adhesion, hardness and corrosion resistance of the coating, and obtains a fluorine-containing oil alcoholysis product;

[0016] S2, the fluorine-containing oil alcoholysis product described in step S1 is added to the reactor, heated to 70-80℃ under nitrogen protection, 20.0-30.0 g hexamethylene diisocyanate is added, and 0.08 g dibutyltin dilaurate is dropped, and reacted for 70-90 min, then 35.0-40.0 g hydroxyethyl methacrylate is added for capping, and the reaction is continued for 50-60 min, then the temperature of the reactor is reduced to 40-50℃, 1.0-1.2 g dimethylol propionic acid, 0.01-0.03 g dibutyltin dilaurate are added, and the temperature is raised to 70-80℃ for 120-150 min, after the reaction is completed, the temperature is reduced to 60-65℃, 1.5-2.0 g hydroxypropyl methacrylate is added and reacted for 120-150 min, then 200 mL of 3.0-3.4% sodium dodecyl sulfate aqueous solution, 65.0-75.0 g butyl acrylate are added to the reaction system, dispersed and emulsified for 100-120 min, then the temperature is raised to 80-85℃, and the initiator solution is slowly dropped in 2 h, and the reaction is carried out for 200-300 min, the initiator solution is prepared by 0.8-1.0 g ammonium persulfate and 40 mL deionized water, finally the temperature is reduced to 40-45℃, ammonia solution is added to adjust the pH to 7.5-7.8, the filtrate is obtained, through the bridge monomer of hydroxyethyl methacrylate and hydroxypropyl methacrylate, the chemical bond between the polyurethane chain and the polyacrylate chain is connected, forming a kind of interpenetrating network structure with fluorine modification and crosslinkable hybrid emulsion, and in the process of film formation and curing, the fluorine-containing segment will spontaneously migrate and enrich to the interface between the coating and the air, forming a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, obtaining a high-performance modified acrylic resin emulsion;

[0017] S3, hydroxymethyl cellulose, deionized water is added to a high-speed mixer, stirring at 300-500 rpm speed until completely dissolved, then at 500-800 rpm speed, adding BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles are pre-dispersed in turn, adjust the stirring speed to 2000-2500 rpm, stirring time 10-20 min, then reduce the speed to 800-1000 rpm, the high performance modified acrylic resin emulsion, BYK-011 defoamer and BYK-358N leveling agent described in step S2 are added, keep the speed unchanged for 20-30 min, finally the material is transferred to a horizontal sand mill for circulation grinding, ensure that the fineness of the particles is not more than 25μm, functionalized hexagonal boron nitride tannic acid silica hybrid particles as rigid filler, after high-speed dispersion and sanding, are uniformly and stably dispersed in the high performance modified acrylic resin emulsion matrix, while the continuous and dense three-dimensional polymer network formed by the high performance modified acrylic resin emulsion uniformly and firmly bonds all components together, forming a coating protection system with active repulsion, physical barrier, chemical inertia and mechanical toughness, which gives the coating excellent hardness, adhesion and corrosion resistance through multiple barrier effects, and obtains a steel pipe anticorrosion coating;

[0018] Preferably, in step S1, the amount of hexafluorohexane diisocyanate added is 30.0-40.0g, and the fluorine element introduced by hexafluorohexane diisocyanate gives the resin excellent hydrophobic, oleophobic, stain-resistant and chemical corrosion resistance.

[0019] The beneficial effects obtained by the present application are as follows:

[0020] The application embeds and disperses functionalized hexagonal boron nitride tannic acid silica hybrid particles uniformly in a high-performance modified acrylic resin emulsion matrix as a composite reinforcing main body, and in the process of curing and film forming, the hybrid particles and the fluorine-containing segments in the resin spontaneously migrate and enrich to the interface of the coating and air to form a nanoscale, low-surface-energy dense outer layer, which not only enhances the hardness of the coating and the adhesion to the steel pipe, but also significantly improves the corrosion resistance of the coating by constructing a multi-protection barrier that combines active repulsion, physical barrier, chemical inertia and interface reinforcement, effectively meeting the corrosion prevention requirements; in the functionalized hexagonal boron nitride tannic acid silica hybrid particles, hexagonal boron nitride is the core, which is coated with tannic acid to improve the compatibility and bonding force of hexagonal boron nitride, and provides abundant nucleation sites for the deposition of silica, ensuring the uniform, complete and dense growth of silica, and then octadecyltrimethoxysilane is grafted onto the surface of the silica shell layer to form a functional modification outer layer, wherein the introduced long-chain octadecyl group has good compatibility with the resin matrix and can effectively embed in the polymer network, the internal tannic acid and silica are rich in polar hydroxyl groups, which can not only form strong hydrogen bonds with the resin, but also form coordination bonds or chemical bonds with the hydroxyl groups or metal oxides on the surface of the metal substrate, thereby improving the adhesion, and the hard silica shell layer and hexagonal boron nitride hard core work together to improve the overall hardness of the coating, at the same time, the construction of the multi-layer dense barrier and the micro-nano rough structure with low surface energy realizes super protection, greatly reduces the invasion of corrosion medium and water accompanying corrosion medium to the surface of the steel pipe, and provides long-term protection; in the high-performance modified acrylic resin emulsion, the chemical bond between the polyurethane chain and the polyacrylate chain is connected through the bridge monomers of hydroxyethyl methacrylate and hydroxypropyl methacrylate to form a kind of interpenetrating network structure of fluorine-modified and cross-linkable hybrid emulsion, the urethane bond, carboxyl group and urea bond in the polyurethane segment can form strong hydrogen bonds and van der waals forces with the metal oxides and hydroxyl groups on the surface of the steel pipe to realize stable anchoring, and the double bonds introduced by hydroxyethyl methacrylate and hydroxypropyl methacrylate form a highly cross-linked three-dimensional network structure with butyl acrylate under initiation, which directly improves the high hardness and rigidity of the coating after curing, and in the process of coating film forming and curing, the fluorine-containing segments spontaneously migrate and enrich to the interface of the coating and air to form a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, effectively improving the corrosion resistance; the application uses functionalized hexagonal boron nitride tannic acid silica hybrid particles, high-performance modified water-resistant acrylic resin emulsion, titanium dioxide, BYK-190 dispersant, BYK-011 defoamer, BYK-358N leveling agent, hydroxymethyl cellulose and deionized water to prepare a steel pipe anticorrosive coating, which effectively improves the adhesion, hardness and corrosion resistance of the coating and improves the use effect of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The adhesion results chart of the present application examples 1-4 and comparative examples 1-3;

[0022] Figure 2 The pencil hardness results chart of the coating of the present application examples 1-4 and comparative examples 1-3;

[0023] Figure 3 The maximum length of corrosion results chart of the present application examples 1-4 and comparative examples 1-3. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by one of ordinary skill in the art. In addition, any method and material similar or equivalent to those described herein can be used in the present application. The preferred implementation methods and materials described herein are only used for demonstration, but cannot limit the content of the present application.

[0026] The experimental methods in the following embodiments are all conventional methods unless otherwise specified. The experimental materials used in the following embodiments are all purchased from commercial channels unless otherwise specified.

[0027] Example 1

[0028] The present embodiment proposes a steel pipe anticorrosive coating, which comprises the following components by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 6 parts, high-performance modified water-resistant acrylic resin emulsion 60 parts, titanium dioxide 20 parts, BYK-190 dispersant 0.5 parts, BYK-011 defoamer 0.4 parts, BYK-358N leveling agent 0.4 parts, hydroxymethyl cellulose 0.5 parts, and deionized water 20 parts.

[0029] The functionalized hexagonal boron nitride tannic acid silica hybrid particles are made of the following components by weight: hexagonal boron nitride 10 parts, tannic acid 5 parts, tetraethyl orthosilicate 6 parts, and octadecyl trimethoxysilane 17.6 parts.

[0030] The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles specifically comprises the following steps:

[0031] (1) 1.0 g of hexagonal boron nitride was first ultrasonically dispersed in 200 mL of deionized water, then added to 50 mL of a 0.4% by mass sodium hydroxide solution with a pH of 8.5, then tannic acid was added, the amount of tannic acid added was 0.5 g, tannic acid can firmly fix the coating on the surface of the steel pipe by virtue of strong metal chelation, and further provides a synergistic guarantee for corrosion resistance by enhancing adhesion and improving filler dispersion, under the conditions of 300 rpm magnetic stirring and 60°C water bath, the reaction was carried out for 3 h, then centrifuged, the precipitate was washed with anhydrous ethanol and deionized water in turn until the washing liquid was neutral and there was no yellow or brown color, the coating of tannic acid on hexagonal boron nitride improved the compatibility and bonding force of hexagonal boron nitride with the resin matrix, and the uniformly dispersed rigid hexagonal boron nitride layers not only hindered the slipping and deformation of the resin molecular chain, improving the hardness of the coating after film formation, but also arranged in parallel in the coating, forming a zigzag physical barrier, greatly prolonging the penetration path of corrosion media such as water, oxygen, chloride ions, etc. to the surface of the steel pipe, thereby producing a synergistic enhancement effect, obtaining a wet state hexagonal boron nitride@tannic acid precipitate;

[0032] (2) The wet state of the hexagonal boron nitride @ tannic acid precipitate described in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, while 100 mL of anhydrous ethanol, 20 mL of deionized water and 5 mL of 28% mass fraction of ammonia are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, under the condition of 300 rpm magnetic stirring and 30℃, using a constant pressure dropping funnel to add tetraethyl orthosilicate, controlling the dropping speed to be 2s per drop, the amount of tetraethyl orthosilicate added is 0.6 mL, under the catalysis of ammonia, tetraethyl orthosilicate will hydrolyze and condense to form silica, and deposit and grow on the surface of hexagonal boron nitride @ tannic acid with rich hydroxyl group, and finally form a uniform and complete shell layer, after the addition is completed, continue to react under the same conditions for 24h, centrifugal, the precipitate is washed with anhydrous ethanol and deionized water for 5 times respectively, and dried in a vacuum oven at 80℃, grinding, in this process, the construction of the silica shell layer not only can form strong hydrogen bonds with the metal hydroxyl group on the surface of the steel pipe, but also can form a firm hydrogen bond network with the resin matrix, also increase the interface roughness, which is beneficial to the effective mechanical interlocking effect with the resin matrix, so as to not only improve the interface compatibility of hexagonal boron nitride and the matrix, but also improve the overall adhesion, at the same time, this core-shell structure of hexagonal boron nitride and silica forms a rigid hybrid reinforcing unit, when they are uniformly dispersed in the relatively soft polymer matrix, they can effectively resist external stress and deformation, improve the hardness of the coating, and the silica shell layer itself has a dense structure, which can effectively block the penetration of water, oxygen and corrosive ions, its cooperation with the flaky hexagonal boron nitride core makes the maze path of the diffusion of corrosive medium in the coating more tortuous and long, by constructing a dense barrier and stable interface to improve the corrosion resistance, and get hexagonal boron nitride @ tannic acid silica hybrid particles;

[0033] (3) The hexagonal boron nitride@tannic acid silica hybrid particles obtained in step (2) are ultrasonically dispersed in 300 mL of anhydrous ethanol, and then octadecyltrimethoxysilane is added, the amount of octadecyltrimethoxysilane added being 2.0 mL, the long alkyl chain introduced by octadecyltrimethoxysilane having excellent compatibility with the resin matrix, which is conducive to the uniform dispersion of the hybrid particles in the resin, ensuring the uniformity and stability of the coating hardness, and the reaction is carried out under the conditions of 300 rpm magnetic stirring and 60°C water bath for 12 h, after the reaction is completed, centrifugation is performed, the precipitate is washed with anhydrous ethanol and deionized water in sequence until the washing liquid is neutral, and finally dried in a vacuum oven at 80°C, ground, and the octadecyltrimethoxysilane is grafted on the surface of the hexagonal boron nitride@tannic acid silica hybrid particles through covalent bonds, the long chain octadecyl groups of the low surface energy groups extending outward are densely arranged, so that water molecules cannot wet the surface, reducing the invasion of corrosion medium from the source, and also reducing the damage of water to the coating-substrate interface, thereby reducing the risk of blistering and peeling after the coating is formed, and protecting the firm adhesion established by tannic acid and silica, to obtain functionalized hexagonal boron nitride@tannic acid silica hybrid particles.

[0034] The embodiment provides a preparation method of a steel pipe anti-corrosion coating, and specifically comprises the following steps.

[0035] S1, 110.0 g of castor oil and 30.0 g of trimethylolpropane are added to a reactor, and then dehydrated under nitrogen protection at 120°C for 30 min, and then cooled to 80°C, 10.0 g of dimethylolpropionic acid and 30.0 g of acetone are added, stirred to dissolve, and then slowly added with hexafluorohexane diisocyanate and 0.1 g of dibutyltin dilaurate as a catalyst, the amount of hexafluorohexane diisocyanate added being 40.0 g, the fluorine element introduced by hexafluorohexane diisocyanate endowing the resin with excellent hydrophobicity, oleophobicity, stain resistance and chemical corrosion resistance, the reaction is carried out at 80°C until the NCO characteristic absorption peak disappears, and then acetone is removed by distillation under reduced pressure, a fluorinated polyurethane oligomer with flexibility, crosslinking potential, water dispersibility and top surface performance is synthesized by the process, which serves as a skeleton structure of a subsequent resin system, laying a foundation for the adhesion, hardness and corrosion resistance of the coating, and a fluorine-containing oil alcoholysis product is obtained.

[0036] S2, the fluorine-containing alcoholysis product described in step S1 is added to a reactor, and heated to 80℃ under nitrogen protection, 30.0g hexamethylene diisocyanate is added, and 0.08g dibutyltin dilaurate is added dropwise, and reacted for 90min, then 40.0g hydroxyethyl methacrylate is added for capping, and the reaction is continued for 60min, then the temperature of the reactor is reduced to 50℃, 1.2g dimethylol propionic acid, 0.03g dibutyltin dilaurate is added dropwise, and the temperature is raised to 80℃ and reacted for 150min, after the reaction is completed, the temperature is reduced to 65℃, 2.0g hydroxypropyl methacrylate is added and reacted for 150min, then 200mL of 3.4% sodium dodecyl sulfate aqueous solution, 75.0g butyl acrylate is added to the reaction system, and dispersed and emulsified for 120min, then the temperature is raised to 85℃, and the initiator solution is slowly added dropwise within 2h, and the reaction is carried out for 300min, the initiator solution is prepared by 1.0g ammonium persulfate and 40mL deionized water, finally the temperature is reduced to 45℃, and an ammonia solution is added to adjust the pH to 7.8, and the filtrate is obtained, the bridge monomers of hydroxyethyl methacrylate and hydroxypropyl methacrylate are used to connect the polyurethane chain and the polyacrylate chain, forming a kind of interpenetrating network structure of fluorine modified and crosslinkable hybrid emulsion, and in the process of film forming and curing, the fluorine-containing segment will spontaneously migrate and enrich to the interface between the coating and the air, forming a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, and a high-performance modified acrylic resin emulsion is obtained;

[0037] S3, hydroxymethyl cellulose and deionized water are added to a high-speed mixer, stirred at 500rpm until completely dissolved, then pre-dispersed with BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles at 800rpm, adjust the stirring speed to 2500rpm, stir for 20min, then reduce the speed to 1000rpm, add the high-performance modified acrylic resin emulsion described in step S2, BYK-011 defoamer and BYK-358N leveling agent, keep the speed unchanged and disperse for 30min, finally transfer the material to a horizontal sand mill for circulation grinding, ensure that the particle size is not more than 25μm, the functionalized hexagonal boron nitride tannic acid silica hybrid particles as rigid filler, after high-speed dispersion and sand grinding, are uniformly and stably dispersed in the high-performance modified acrylic resin emulsion matrix, while the continuous and dense three-dimensional polymer network formed by the high-performance modified acrylic resin emulsion uniformly and firmly bonds all components together, forming a coating protection system with active repulsion, physical barrier, chemical inertia and mechanical toughness, which endows the coating with excellent hardness, adhesion and corrosion resistance through multiple barrier effects, and a steel pipe anticorrosion coating is obtained.

[0038] Example 2

[0039] The embodiment provides a steel pipe anticorrosive coating, which comprises the following components in parts by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 3 parts, high-performance modified water-resistant acrylic resin emulsion 50 parts, titanium white 15 parts, BYK-190 dispersant 0.3 parts, BYK-011 defoaming agent 0.2 parts, BYK-358N leveling agent 0.2 parts, hydroxymethyl cellulose 0.3 parts and deionized water 15 parts.

[0040] The functionalized hexagonal boron nitride tannic acid silica hybrid particles are prepared from the following components in parts by weight: hexagonal boron nitride 8 parts, tannic acid 3 parts, tetraethyl orthosilicate 2 parts and octadecyl trimethoxysilane 8.8 parts.

[0041] The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles specifically comprises the following steps:

[0042] (1) 0.8g of hexagonal boron nitride is first ultrasonically dispersed in 100mL of deionized water, and then added to 50mL of a sodium hydroxide solution with a mass fraction of 0.2% and a pH of 8.5, followed by the addition of tannic acid, and the addition amount of the tannic acid is 0.3g; the tannic acid can firmly fix the coating on the surface of the steel pipe by virtue of strong metal chelation, and further provides a synergistic guarantee for corrosion resistance by enhancing adhesion and improving filler dispersibility; under the conditions of 200rpm magnetic stirring and a 50°C water bath, the mixture is reacted for 2h, and then centrifuged; the precipitate is washed with anhydrous ethanol and deionized water in sequence until the washing liquid is neutral and free of yellow or brown color; the coating of the tannic acid on the hexagonal boron nitride improves the compatibility and binding force of the hexagonal boron nitride with a resin matrix; uniformly dispersed rigid hexagonal boron nitride layers not only can hinder the slippage and deformation of resin molecular chains, and improve the hardness of the coating after film formation, but also can be arranged in parallel in the coating, forming a zigzag physical barrier, greatly prolonging the penetration path of corrosion media such as water, oxygen and chloride ions to the surface of the steel pipe, thereby producing a synergistic enhancement effect; and the wet-state hexagonal boron nitride@tannic acid precipitate is obtained;

[0043] (2) The wet state of the hexagonal boron nitride @ tannic acid precipitate described in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, while 100 mL of anhydrous ethanol, 20 mL of deionized water and 3 mL of 25% ammonia water are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, under the condition of 200 rpm magnetic stirring and 30℃, using a constant pressure dropping funnel to add tetraethyl orthosilicate, controlling the dropping speed to be 1 s per drop, the amount of tetraethyl orthosilicate added is 0.2 mL, under the catalysis of ammonia water, tetraethyl orthosilicate will hydrolyze and condense to form silicon dioxide, and deposit and grow on the surface of the hexagonal boron nitride @ tannic acid with rich hydroxyl groups, and finally form a uniform and complete shell layer, after the addition is completed, continue to react under the same conditions for 12 h, centrifugal, the precipitate is washed with anhydrous ethanol and deionized water for 3 times respectively, and dried in a vacuum oven at 60℃, grinding, in this process, the construction of the silicon dioxide shell layer not only can form strong hydrogen bonds with the metal hydroxyl groups on the surface of the steel pipe, but also can form a firm hydrogen bond network with the resin matrix, also increase the interface roughness, which is beneficial to the effective mechanical interlocking effect with the resin matrix, thereby not only improving the interface compatibility of hexagonal boron nitride and the matrix, but also improving the overall adhesion, at the same time, this core-shell structure of hexagonal boron nitride and silicon dioxide forms a rigid hybrid reinforcing unit, which can effectively resist external stress and deformation when uniformly dispersed in the relatively soft polymer matrix, improving the hardness of the coating, and the silicon dioxide shell layer itself has a dense structure, which can effectively block the penetration of water, oxygen and corrosive ions, its cooperation with the flaky hexagonal boron nitride core makes the maze path of the corrosion medium in the coating more tortuous and long, and improves the corrosion resistance by building a dense barrier and stable interface, to obtain hexagonal boron nitride @ tannic acid silicon dioxide hybrid particles;

[0044] (3) The hexagonal boron nitride@tannic acid silica hybrid particles prepared in step (2) are ultrasonically dispersed in 200 mL of anhydrous ethanol, and then octadecyltrimethoxysilane is added, the amount of octadecyltrimethoxysilane added being 1.0 mL, the long alkyl chain introduced by octadecyltrimethoxysilane having excellent compatibility with the resin matrix, which is conducive to the uniform dispersion of the hybrid particles in the resin, ensuring the uniformity and stability of the coating hardness, and the reaction is carried out under the conditions of 200 rpm magnetic stirring and 50°C water bath for 8 h, after the reaction is completed, centrifugation is performed, the precipitate is washed with anhydrous ethanol and deionized water in sequence until the washing liquid is neutral, and finally the precipitate is dried in a vacuum oven at 60°C, ground, and octadecyltrimethoxysilane is grafted on the surface of the hexagonal boron nitride@tannic acid silica hybrid particles through covalent bonds, the long chain octadecyl groups of the low surface energy groups extending outward are densely arranged, so that water molecules cannot wet the surface, reducing the invasion of corrosion media from the source, and also reducing the damage of water to the coating-substrate interface, thereby reducing the risk of blistering and peeling of the coating after film formation, and protecting the firm adhesion established by tannic acid and silica, to obtain functionalized hexagonal boron nitride@tannic acid silica hybrid particles.

[0045] The embodiment provides a preparation method of a steel pipe anti-corrosion coating, and specifically comprises the following steps:

[0046] S1, 100.0 g of castor oil, 20.0 g of trimethylolpropane are added to a reactor, and dehydrated under nitrogen protection at 120°C for 20 min, then cooled to 80°C, 8.0 g of dimethylolpropionic acid and 25.0 g of acetone are added, stirred to dissolve, then slowly drop 30.0 g of hexafluorohexane diisocyanate and 0.1 g of dibutyltin dilaurate catalyst, the fluorine element introduced by hexafluorohexane diisocyanate endows the resin with excellent hydrophobicity, oleophobicity, stain resistance and chemical corrosion resistance, the reaction is carried out at 80°C until the NCO characteristic absorption peak disappears, and the acetone is removed by distillation under reduced pressure, the process synthesizes a fluorinated polyurethane oligomer with flexibility, crosslinking potential, water dispersibility and top surface performance, which serves as the backbone structure of the subsequent resin system, laying a foundation for the adhesion, hardness and corrosion resistance of the coating, and obtaining a fluorine-containing oil alcoholysis product;

[0047] S2, the fluorine-containing alcoholysis product described in step S1 is added to a reactor, and heated to 70°C under nitrogen protection, 20.0 g of hexamethylene diisocyanate is added, and 0.08 g of dibutyltin dilaurate is added dropwise, and reacted for 70 min, then 35.0 g of hydroxyethyl methacrylate is added for capping, and reacted for 50 min, then the temperature of the reactor is reduced to 40°C, 1.0 g of dimethylol propionic acid, 0.01 g of dibutyltin dilaurate is added dropwise, and then heated to 70°C and reacted for 120 min, after the reaction is completed, the temperature is reduced to 60°C, 1.5 g of hydroxypropyl methacrylate is added and reacted for 120 min, then 200 mL of 3.0% sodium dodecyl sulfate aqueous solution, 65.0 g of butyl acrylate is added to the reaction system, and dispersed and emulsified for 100 min, then the temperature is raised to 80°C, and the initiator solution is slowly added dropwise within 2 h, and reacted for 200 min, the initiator solution is prepared from 0.8 g of ammonium persulfate and 40 mL of deionized water, finally the temperature is reduced to 40°C, and an ammonia solution is added to adjust the pH to 7.5, and the filtrate is obtained, the bridge monomers of hydroxyethyl methacrylate and hydroxypropyl methacrylate are used to connect the polyurethane chain and the polyacrylate chain, forming a kind of interpenetrating network structure of fluorine modified and crosslinkable hybrid emulsion, and in the process of film forming and curing, the fluorine-containing segment will spontaneously migrate and enrich to the interface between the coating and the air, forming a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, obtaining a high performance modified acrylic resin emulsion;

[0048] S3, hydroxymethyl cellulose and deionized water are added to a high-speed mixer, stirred at 300 rpm until completely dissolved, then pre-dispersed with BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles at 500 rpm, adjust the stirring speed to 2000 rpm, and stir for 10 min, then reduce the speed to 800 rpm, add the high performance modified acrylic resin emulsion described in step S2, BYK-011 defoamer and BYK-358N leveling agent, keep the speed unchanged and disperse for 20 min, finally transfer the material to a horizontal sand mill for circulation grinding, ensure that the particle size is not more than 25 μm, the functionalized hexagonal boron nitride tannic acid silica hybrid particles as rigid filler, after high-speed dispersion and sand milling, are uniformly and stably dispersed in the high performance modified acrylic resin emulsion matrix, while the continuous and dense three-dimensional polymer network formed by the high performance modified acrylic resin emulsion uniformly and firmly bonds all components together, forming a coating protection system with active repulsion, physical barrier, chemical inertia and mechanical toughness, which endows the coating with excellent hardness, adhesion and corrosion resistance through multiple barrier effects, obtaining a steel pipe anti-corrosion coating.

[0049] Example 3

[0050] The embodiment provides a steel pipe anticorrosive coating, which comprises the following components in parts by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 4.5 parts, high-performance modified water-resistant acrylic resin emulsion 55 parts, titanium white 17.5 parts, BYK-190 dispersant 0.4 parts, BYK-011 defoaming agent 0.3 parts, BYK-358N leveling agent 0.3 parts, hydroxymethyl cellulose 0.4 parts, and deionized water 17.5 parts.

[0051] The functionalized hexagonal boron nitride tannic acid silica hybrid particles are prepared from the following components in parts by weight: hexagonal boron nitride 9 parts, tannic acid 4 parts, tetraethyl orthosilicate 4 parts, and octadecyltrimethoxysilane 13.2 parts.

[0052] The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles specifically comprises the following steps:

[0053] (1) 0.9 g of hexagonal boron nitride is first ultrasonically dispersed in 150 mL of deionized water, and then added to 50 mL of a sodium hydroxide solution with a mass fraction of 0.3% and a pH of 8.5; then tannic acid is added, and the addition amount of the tannic acid is 0.4 g; the tannic acid can firmly fix the coating on the surface of the steel pipe by virtue of strong metal chelation, and further provides a synergistic guarantee for corrosion resistance by enhancing adhesion and improving filler dispersibility; under the conditions of 250 rpm magnetic stirring and a 55 ℃ water bath, the mixture is reacted for 2.5 h, and then centrifuged; the precipitate is sequentially washed with anhydrous ethanol and deionized water until the washing liquid is neutral and free of yellow or brown color; the coating of the tannic acid on the hexagonal boron nitride improves the compatibility and binding force of the hexagonal boron nitride with a resin matrix; uniformly dispersed rigid hexagonal boron nitride layers not only can hinder the slippage and deformation of resin molecular chains, and improve the hardness of the coating after film formation, but also can be arranged in parallel in the coating, to form a zigzag physical barrier, greatly prolonging the penetration path of corrosion media such as water, oxygen and chloride ions to the surface of the steel pipe, thereby producing a synergistic enhancement effect; and the wet-state hexagonal boron nitride@tannic acid precipitate is obtained;

[0054] (2) The wet state of the hexagonal boron nitride @ tannic acid precipitate described in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, while 100 mL of anhydrous ethanol, 20 mL of deionized water and 4 mL of 27% ammonia water are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, under the condition of 250 rpm magnetic stirring and 30℃, using a constant pressure dropping funnel to add tetraethyl orthosilicate, controlling the dropping speed to be 1.5 s per drop, the amount of tetraethyl orthosilicate added is 0.4 mL, under the catalysis of ammonia water, tetraethyl orthosilicate will hydrolyze and condense to form silica, and deposit and grow on the surface of the hexagonal boron nitride @ tannic acid with rich hydroxyl group, eventually forming a uniform and complete shell layer, after the addition is completed, continue to react under the same conditions for 18 h, centrifugal, the precipitate is washed with anhydrous ethanol and deionized water for 4 times respectively, and dried in a vacuum oven at 70℃, grinding, in this process, the construction of the silica shell layer not only can form strong hydrogen bonds with the metal hydroxyl group on the surface of the steel pipe, but also can form a firm hydrogen bond network with the resin matrix, also increase the interface roughness, which is beneficial to the effective mechanical interlocking effect with the resin matrix, thus not only improving the interface compatibility of hexagonal boron nitride and the matrix, but also improving the overall adhesion, at the same time, this core-shell structure of hexagonal boron nitride and silica forms a rigid hybrid reinforcing unit, when they are uniformly dispersed in the relatively soft polymer matrix, they can effectively resist external stress and deformation, improve the hardness of the coating, and the silica shell layer itself has a dense structure, which can effectively block the penetration of water, oxygen and corrosive ions, its cooperation with the flaky hexagonal boron nitride core makes the maze path of the corrosion medium in the coating more tortuous and long, by constructing a dense barrier and stable interface to improve the corrosion resistance, and get the hexagonal boron nitride @ tannic acid silica hybrid particles;

[0055] (3) The hexagonal boron nitride@tannic acid silica hybrid particles prepared in step (2) are ultrasonically dispersed in 250 mL of anhydrous ethanol, and then octadecyltrimethoxysilane is added, the amount of octadecyltrimethoxysilane added is 1.5 mL, the long alkyl chain introduced by octadecyltrimethoxysilane has excellent compatibility with the resin matrix, which is beneficial to the uniform dispersion of the hybrid particles in the resin, ensuring the uniformity and stability of the coating hardness, and the reaction is carried out under the conditions of 250 rpm magnetic stirring and 55°C water bath for 10 h, after the reaction is completed, centrifugation is carried out, the precipitate is washed with anhydrous ethanol and deionized water in turn until the washing liquid is neutral, and finally dried in a vacuum oven at 70°C, ground, octadecyltrimethoxysilane is grafted on the surface of the hexagonal boron nitride@tannic acid silica hybrid particles through covalent bond, and the long chain octadecyl with low surface energy group arranged densely outward, so that water molecules cannot wet the surface, reducing the invasion of corrosion medium from the source, while also reducing the damage of water to the coating-substrate interface, thereby reducing the risk of blistering and peeling after the coating is formed, protecting the firm adhesion established by tannic acid and silica, and obtaining functionalized hexagonal boron nitride tannic acid silica hybrid particles.

[0056] The embodiment provides a preparation method of a steel pipe anti-corrosion coating, and specifically comprises the following steps:

[0057] S1, 105.0 g of castor oil and 25.0 g of trimethylolpropane are added to a reactor, and then dehydrated under nitrogen protection at 120°C for 25 min, and then cooled to 80°C, 9.0 g of dimethylolpropionic acid and 27.5 g of acetone are added, stirred to dissolve, and then slowly added with hexafluorohexane diisocyanate and 0.1 g of dibutyltin dilaurate catalyst, the amount of hexafluorohexane diisocyanate added is 35.0 g, and the fluorine element introduced by hexafluorohexane diisocyanate endows the resin with excellent hydrophobicity, oleophobicity, stain resistance and chemical corrosion resistance, and the reaction is carried out at 80°C until the NCO characteristic absorption peak disappears, and then acetone is removed by distillation under reduced pressure, a fluorinated polyurethane oligomer with flexibility, crosslinking potential, water dispersibility and top surface performance is synthesized by the process, which serves as the skeleton structure of the subsequent resin system, lays a foundation for the adhesion, hardness and corrosion resistance of the coating, and obtains a fluorine-containing oil alcoholysis product;

[0058] S2, the fluorine-containing oil alcoholysis product described in step S1 is added to a reactor, and heated to 75°C under nitrogen protection, 25.0 g of hexamethylene diisocyanate is added, and 0.08 g of dibutyltin dilaurate is added dropwise, and reacted for 80 min, then 37.5 g of hydroxyethyl methacrylate is added for capping, and reacted for 55 min, then the temperature of the reactor is reduced to 45°C, 1.1 g of dimethylol propionic acid, 0.02 g of dibutyltin dilaurate is added dropwise, and then heated to 75°C and reacted for 135 min, after the reaction is completed, the temperature is reduced to 62.5°C, 1.75 g of hydroxypropyl methacrylate is added and reacted for 135 min, then 200 mL of 3.2% sodium dodecyl sulfate aqueous solution, 70.0 g of butyl acrylate is added to the reaction system, and dispersed and emulsified for 110 min, then the temperature is increased to 82.5°C, and the initiator solution is slowly added dropwise within 2 h, and reacted for 250 min, the initiator solution is prepared from 0.9 g of ammonium persulfate and 40 mL of deionized water, finally the temperature is reduced to 42.5°C, and an ammonia solution is added to adjust the pH to 7.7, and the filtrate is obtained, the bridge monomers of hydroxyethyl methacrylate and hydroxypropyl methacrylate are used to connect the polyurethane chain and the polyacrylate chain, forming a kind of interpenetrating network structure of fluorine modified and crosslinkable hybrid emulsion, and in the process of film forming and curing, the fluorine-containing segment will spontaneously migrate and enrich to the interface between the coating and the air, forming a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, obtaining a high performance modified acrylic resin emulsion;

[0059] S3, hydroxymethyl cellulose and deionized water are added to a high-speed mixer, stirred at 400 rpm until completely dissolved, then pre-dispersed with BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles are added in turn at 650 rpm, the stirring speed is adjusted to 2250 rpm, and the stirring time is 15 min, then the stirring speed is reduced to 900 rpm, the high performance modified acrylic resin emulsion described in step S2, BYK-011 defoamer and BYK-358N leveling agent are added, the stirring speed is kept unchanged for 25 min, and finally the material is transferred to a horizontal sand mill for circulation grinding to ensure that the particle size is not more than 25 μm, the functionalized hexagonal boron nitride tannic acid silica hybrid particles are used as rigid fillers, which are uniformly and stably dispersed in the high performance modified acrylic resin emulsion matrix after high-speed dispersion and sand milling, and the continuous and dense three-dimensional polymer network formed by the high performance modified acrylic resin emulsion uniformly and firmly bonds all components together, forming a coating protection system with active repulsion, physical barrier, chemical inertness and mechanical toughness, which endows the coating with excellent hardness, adhesion and corrosion resistance through multiple barrier effects, obtaining a steel pipe anti-corrosion coating.

[0060] Example 4

[0061] The embodiment provides a steel pipe anticorrosive coating, which comprises the following components in parts by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 6 parts, high-performance modified water-resistant acrylic resin emulsion 50 parts, titanium white 20 parts, BYK-190 dispersant 0.5 parts, BYK-011 defoaming agent 0.4 parts, BYK-358N leveling agent 0.4 parts, hydroxymethyl cellulose 0.5 parts and deionized water 20 parts.

[0062] The functionalized hexagonal boron nitride tannic acid silica hybrid particles are prepared from the following components in parts by weight: hexagonal boron nitride 10 parts, tannic acid 3 parts, tetraethyl orthosilicate 2-6 parts and octadecyltrimethoxysilane 8.8 parts.

[0063] The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles specifically comprises the following steps:

[0064] (1) 1.0 g of hexagonal boron nitride is first ultrasonically dispersed in 200 mL of deionized water, and then added to 50 mL of a sodium hydroxide solution with a mass fraction of 0.4% and a pH of 8.5; then tannic acid is added, and the addition amount of the tannic acid is 0.3 g; the tannic acid can firmly fix the coating on the surface of the steel pipe by virtue of strong metal chelation, and further provides a synergistic guarantee for corrosion resistance by enhancing adhesion and improving filler dispersibility; under the conditions of 300 rpm magnetic stirring and a 60°C water bath, the mixture is reacted for 2 h, and then centrifuged; the precipitate is sequentially washed with anhydrous ethanol and deionized water until the washing liquid is neutral and free of yellow or brown color; the coating of the tannic acid on the hexagonal boron nitride improves the compatibility and binding force of the hexagonal boron nitride with a resin matrix; uniformly dispersed rigid hexagonal boron nitride layers not only can hinder the slippage and deformation of resin molecular chains, and improve the hardness of the coating after film formation, but also can be arranged in parallel in the coating, forming a zigzag physical barrier, greatly prolonging the penetration path of corrosion media such as water, oxygen and chloride ions to the surface of the steel pipe, thereby producing a synergistic enhancement effect; and the wet-state hexagonal boron nitride@tannic acid precipitate is obtained;

[0065] (2) The wet state of the hexagonal boron nitride @ tannic acid precipitate described in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, while 100 mL of anhydrous ethanol, 20 mL of deionized water and 5 mL of 28% mass fraction of ammonia are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, under the condition of 300 rpm magnetic stirring and 30℃, using a constant pressure dropping funnel to add tetraethyl orthosilicate, controlling the dropping speed to be 2s per drop, the amount of tetraethyl orthosilicate added is 0.6 mL, under the catalysis of ammonia, tetraethyl orthosilicate will hydrolyze and condense to form silica, and deposit and grow on the surface of hexagonal boron nitride @ tannic acid with rich hydroxyl group, and finally form a uniform and complete shell layer, after the addition is completed, continue to react under the same conditions for 12h, centrifugal, the precipitate is washed with anhydrous ethanol and deionized water for 5 times respectively, and dried in a vacuum oven at 80℃, grinding, in this process, the construction of the silica shell layer not only can form strong hydrogen bonds with the metal hydroxyl group on the surface of the steel pipe, but also can form a firm hydrogen bond network with the resin matrix, also increase the interface roughness, which is beneficial to the effective mechanical interlocking effect with the resin matrix, so as to not only improve the interface compatibility of hexagonal boron nitride and the matrix, but also improve the overall adhesion, at the same time, this core-shell structure of hexagonal boron nitride and silica forms a rigid hybrid reinforcing unit, when they are uniformly dispersed in the relatively soft polymer matrix, they can effectively resist external stress and deformation, improve the hardness of the coating, and the silica shell layer itself has a dense structure, which can effectively block the penetration of water, oxygen and corrosive ions, its cooperation with the flaky hexagonal boron nitride core makes the maze path of the diffusion of corrosive medium in the coating more tortuous and long, by constructing a dense barrier and stable interface to improve the corrosion resistance, and get hexagonal boron nitride @ tannic acid silica hybrid particles;

[0066] (3) The hexagonal boron nitride@tannic acid silica hybrid particles prepared in step (2) are ultrasonically dispersed in 300 mL of anhydrous ethanol, and then octadecyltrimethoxysilane is added, the amount of octadecyltrimethoxysilane added is 1.0 mL, the long alkyl chain introduced by octadecyltrimethoxysilane has excellent compatibility with the resin matrix, which is beneficial to the uniform dispersion of the hybrid particles in the resin, ensuring the uniformity and stability of the coating hardness, and the reaction is carried out under the conditions of 300 rpm magnetic stirring and 60°C water bath for 8 h, after the reaction is completed, centrifugation is carried out, the precipitate is washed with anhydrous ethanol and deionized water in turn until the washing liquid is neutral, and finally dried in a vacuum oven at 80°C, ground, and the octadecyltrimethoxysilane is grafted on the surface of the hexagonal boron nitride@tannic acid silica hybrid particles by covalent bond, the long chain octadecyl with low surface energy group arranged densely outward, so that water molecules cannot wet the surface, reducing the invasion of corrosion medium from the source, while also reducing the damage of water to the coating-substrate interface, thereby reducing the risk of blistering and peeling after the coating is formed, protecting the firm adhesion established by tannic acid and silica, and obtaining functionalized hexagonal boron nitride tannic acid silica hybrid particles.

[0067] The embodiment provides a preparation method of a steel pipe anti-corrosion coating, and specifically comprises the following steps:

[0068] S1, 110.0 g of castor oil, 30.0 g of trimethylolpropane are added to a reactor, and dehydrated under nitrogen protection at 120°C for 20 min, then cooled to 80°C, 10.0 g of dimethylolpropionic acid and 30.0 g of acetone are added, stirred to dissolve, then slowly drop 0.1 g of dibutyltin dilaurate catalyst and 30.0 g of hexafluorohexane diisocyanate, the amount of hexafluorohexane diisocyanate added is 30.0 g, the fluorine element introduced by hexafluorohexane diisocyanate endows the resin with excellent hydrophobicity, oleophobicity, stain resistance and chemical corrosion resistance, the reaction is carried out at 80°C until the NCO characteristic absorption peak disappears, and the acetone is removed by distillation under reduced pressure, a fluorinated polyurethane oligomer with flexibility, crosslinking potential, water dispersibility and top surface performance is synthesized by this process, which serves as the backbone structure of the subsequent resin system, laying a foundation for the adhesion, hardness and corrosion resistance of the coating, and obtaining a fluorine-containing oil alcoholysis product;

[0069] S2, the fluorine-containing alcoholysis product described in step S1 is added to a reactor, and heated to 70-80℃ under nitrogen protection, 30.0g hexamethylene diisocyanate is added, and 0.08g dibutyltin dilaurate is added dropwise, and reacted for 70min, then 35.0g hydroxyethyl methacrylate is added for capping, and reacted for 50min, then the temperature of the reactor is reduced to 50℃, 1.2g dimethylol propionic acid, 0.03g dibutyltin dilaurate is added dropwise, and then heated to 80℃ and reacted for 120min, after the reaction is completed, the temperature is reduced to 65℃, 2.0g hydroxypropyl methacrylate is added and reacted for 120min, then 200mL of a 3.4% sodium dodecyl sulfate aqueous solution, 75.0g butyl acrylate is added to the reaction system, dispersed and emulsified for 100min, then the temperature is increased to 85℃, and an initiator solution is slowly added dropwise over 2h, and reacted for 200min, the initiator solution is prepared from 1.0g ammonium persulfate and 40mL deionized water, finally the temperature is reduced to 45℃, an ammonia solution is added to adjust the pH to 7.8, the filtrate is filtered out, the bridge monomers of hydroxyethyl methacrylate and hydroxypropyl methacrylate are used to connect the polyurethane chain and the polyacrylate chain, forming a kind of interpenetrating network structure of fluorine-modified, cross-linkable hybrid emulsion, and in the process of film formation and curing, the fluorine-containing segment will spontaneously migrate and enrich to the interface between the coating and the air, forming a dense fluorine protective layer, which can effectively block the penetration of water, oxygen and corrosive ions, obtaining a high-performance modified acrylic resin emulsion;

[0070] S3, hydroxymethyl cellulose and deionized water are added to a high-speed mixer, stirred at 500rpm until completely dissolved, then pre-dispersed with BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles are added in sequence at 800rpm, the stirring speed is adjusted to 2500rpm, and the stirring time is 10min, then the stirring speed is reduced to 1000rpm, the high-performance modified acrylic resin emulsion described in step S2, BYK-011 defoamer and BYK-358N leveling agent are added, the stirring speed is kept unchanged for 20min, and finally the material is transferred to a horizontal sand mill for circulation grinding to ensure that the particle size is not more than 25μm, the functionalized hexagonal boron nitride tannic acid silica hybrid particles are used as rigid fillers, which are uniformly and stably dispersed in the high-performance modified acrylic resin emulsion matrix after high-speed dispersion and sand milling, and the continuous and dense three-dimensional polymer network formed by the high-performance modified acrylic resin emulsion uniformly and firmly bonds all components together, forming a coating protection system with active repulsion, physical barrier, chemical inertia and mechanical toughness, which endows the coating with excellent hardness, adhesion and corrosion resistance through multiple barrier effects, obtaining a steel pipe anti-corrosion coating.

[0071] Comparative Example 1

[0072] This comparative example provides a steel pipe corrosion-resistant coating, which is different from Example 1 in that the functionalized hexagonal boron nitride tannic acid silica hybrid particles do not contain ethyl orthosilicate; the preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles does not include step (2); and the preparation method of the steel pipe corrosion-resistant coating is the same as that of Example 1.

[0073] Comparative Example 2

[0074] This comparative example provides a steel pipe corrosion-resistant coating, which is different from Example 1 in that the functionalized hexagonal boron nitride tannic acid silica hybrid particles do not contain tannic acid, octadecyltrimethoxysilane; the preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles does not include step (3), and tannic acid is not added in step (1); and the preparation method of the steel pipe corrosion-resistant coating is the same as that of Example 1.

[0075] Comparative Example 3

[0076] This comparative example provides a steel pipe corrosion-resistant coating, which is different from Example 1 in that the fluorine-containing oil alcoholysis product does not contain hexafluorohexane diisocyanate, and is replaced by hexamethylene diisocyanate; the preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particles is the same as that of Example 1; and in the preparation method of the steel pipe corrosion-resistant coating, hexafluorohexane diisocyanate is replaced by hexamethylene diisocyanate in step S1.

[0077] Experimental Example 1

[0078] Adhesion test

[0079] Test sample: steel pipe corrosion-resistant coatings prepared in Examples 1-4 and Comparative Examples 1-3.

[0080] Test method: The test sample and curing agent were mixed uniformly at a ratio of 5:1, sprayed on a 440C martensitic stainless steel substrate, and after curing (coating thickness of 80±10 μm), a pull-off adhesion tester was used to measure the adhesion according to the ASTM D4541 standard. The pressure system was calibrated by NIST, with an accuracy of ±1% (full scale), and the value was accurate to 0.01.

[0081] Figure 1The adhesion results of Examples 1-4 and Comparative Examples 1-3 are shown in the figure; as shown in the figure, the adhesion of Examples 1-4 is 15.8-17.5 MPa, indicating good adhesion; the adhesion of Comparative Examples 1-3 is 8.9-14.3 MPa, indicating general or poor adhesion; Comparative Example 1 does not contain tetraethyl orthosilicate in the functionalized hexagonal boron nitride tannic acid silica hybrid particles, which cannot generate silica rich in silicon hydroxyl groups, thereby weakening the bonding with the resin matrix and the surface of the steel pipe, and is also not conducive to increasing the roughness and mechanical interlocking effect of the particles, resulting in poor adhesion; Comparative Example 2 does not contain tannic acid and octadecyltrimethoxysilane in the functionalized hexagonal boron nitride tannic acid silica hybrid particles, which cannot exert the strong metal chelation and molecular bridging effect of tannic acid, nor can it reduce the damage of water to the coating-substrate interface by introducing an octadecyl long chain, increasing the risk of blistering and peeling after coating film formation, resulting in poor adhesion; Comparative Example 3 does not contain hexafluorohexane diisocyanate in the fluorine-containing oil alcoholysis product, and is replaced by hexamethylene diisocyanate, which cannot introduce a hydrophobic and rigid fluorine-containing segment, thereby not conducive to reducing the risk of interface peeling by improving the integrity, hardness and water resistance of the coating, resulting in general adhesion.

[0082] Experimental Example 2

[0083] Hardness Experiment

[0084] Test sample: the steel pipe corrosion-resistant coating prepared in Examples 1-4 and Comparative Examples 1-3.

[0085] Test method: the test sample and curing agent were mixed uniformly at a ratio of 5:1, sprayed on a 440C martensitic stainless steel substrate, and after curing (coating thickness was 80±10 μm), the pencil hardness of the coating was tested according to the national standard GB / T6739-2022. First, the wooden part of the pencil was shaved, without damaging the internal cylindrical core during the shaving process, exposing 5-6 mm of the pencil core. The pencil was inserted into the metal trolley at an inclination angle of 45±1°, and the pencil was fixed on the trolley with the help of the clamp. The pencil core was pressed against the coating surface under a load of 7.35±0.15 N. The metal trolley was pushed to an appropriate distance on the coating surface at a slow and uniform speed. After 30 seconds, visual judgment was made under natural light. The test results were recorded by observing whether there were scratches on the coating surface. If there were no scratches, the pencil hardness was gradually increased on the untested coating area until visible scratches appeared on the coating surface. The hardest pencil hardness that did not scratch the coating was used to represent the pencil hardness of the coating.

[0086] Figure 2The pencil hardness results of the coating of Examples 1-4 and Comparative Examples 1-3 are shown in the figure; as shown, the pencil hardness of the coating of Examples 1-4 is all 2H, indicating high hardness; the pencil hardness of the coating of Comparative Examples 1-3 is F-H, indicating general or poor hardness; the functionalized hexagonal boron nitride-tannic acid-silica hybrid particles of Comparative Example 1 do not contain tetraethyl orthosilicate, and cannot be coated on the hexagonal boron nitride with a complete and dense silica shell, weakening the direct enhancement effect of the nano skeleton on the overall hardness of the coating, resulting in poor hardness; the functionalized hexagonal boron nitride-tannic acid-silica hybrid particles of Comparative Example 2 do not contain tannic acid and octadecyltrimethoxysilane, and cannot ensure the stable combination of silica through tannic acid, thereby weakening the hardness enhancement effect, and cannot improve the compatibility of the hybrid particles with the resin matrix through the surface modification of octadecyltrimethoxysilane, which is not conducive to the uniformity and stability of the coating hardness, resulting in poor hardness; the fluorine-containing oil alcoholysis product of Comparative Example 3 does not contain hexafluorohexane diisocyanate, and is replaced by hexamethylene diisocyanate, which cannot increase the hardness of the polyurethane molecular chain and the resin emulsion by introducing the rigid monomer hexafluorohexane diisocyanate, resulting in general hardness.

[0087] Experimental Example 3

[0088] Anti-corrosion experiment

[0089] Test sample: the steel pipe anti-corrosion coating prepared by Examples 1-4 and Comparative Examples 1-3.

[0090] Test method: according to GB / T1771-2007, the test sample and the curing agent are mixed uniformly at a ratio of 5:1, sprayed on a 440C martensitic stainless steel substrate and drawn an X mark to the substrate, and after curing, the coating thickness is 80±10 μm, placed in a salt spray chamber, the temperature is 35±2℃, the salt spray solution deposition amount is 1.5±0.5 mL / h, and a 5% NaCl solution (pH value is 6.5-7.2) is used to carry out salt spray resistance test for 500h, after the test is completed, the rust is peeled off along the X mark, and the length of the maximum corrosion of the substrate is measured, recorded as the maximum corrosion length (mm).

[0091] Figure 3The corrosion maximum length results of examples 1-4 and comparative examples 1-3 are shown in the figure; as shown, the corrosion maximum length of examples 1-4 is 0.3-0.8 mm, indicating that the corrosion resistance is strong; the corrosion maximum length of comparative examples 1-3 is 1.5-3.8 mm, indicating that the corrosion resistance is general or poor; the functionalized hexagonal boron nitride tannic acid silica hybrid particles in comparative example 1 do not contain tetraethyl orthosilicate, and cannot optimize the labyrinth path by the coating of the dense silica layer on the hexagonal boron nitride, increase the difficulty of the diffusion of the corrosion medium, resulting in poor corrosion resistance; the functionalized hexagonal boron nitride tannic acid silica hybrid particles in comparative example 2 do not contain tannic acid and octadecyltrimethoxysilane, which cannot enhance the interface bonding and adhesion by tannic acid, and weaken the interface protection, and cannot introduce the octadecyl long chain to reduce the infiltration of water and corrosion medium from the source, resulting in poor corrosion resistance; the fluorine-containing oil alcoholysis product in comparative example 3 does not contain hexafluorohexane diisocyanate, and is replaced by hexamethylene diisocyanate, which does not have the ability of active migration and water repellency, so that the synthesized acrylic resin emulsion is degraded from super-hydrophobic to ordinary water-resistant, resulting in general corrosion resistance.

[0092] The above experimental results show that the adhesion, hardness and corrosion resistance of examples 1-4 of the present application are obviously better than those of comparative examples 1-3, wherein the adhesion, hardness and corrosion resistance of example 1 using functionalized hexagonal boron nitride tannic acid silica hybrid particles and high-performance modified acrylic resin emulsion are better, higher and stronger, respectively, the functionalized hexagonal boron nitride tannic acid silica hybrid particles are uniformly embedded and dispersed in the high-performance modified acrylic resin emulsion matrix as a composite reinforcement main body, and in the process of curing and film forming, the fluorine-containing segments in the hybrid particles and the resin spontaneously migrate and enrich to the interface between the coating and the air to form a dense outer layer with nanoscale and low surface energy, which not only enhances the hardness of the coating and the adhesion to the steel pipe, but also significantly improves the corrosion resistance of the coating by constructing a multi-protection barrier with active repulsion, physical barrier, chemical inertia and interface reinforcement.

[0093] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application.

[0094] The above describes the present application and its embodiments, which are not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual application is not limited thereto. In general, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, without creative design, similar ways and embodiments of the technical solution should belong to the protection scope of the present application.

Claims

1. A steel pipe anticorrosive coating characterized by: The steel pipe anticorrosion paint comprises the following components in parts by weight: functionalized hexagonal boron nitride tannic acid silica hybrid particles 3-6 parts, high-performance modified water-resistant acrylic resin emulsion 50-60 parts, titanium white 15-20 parts, BYK-190 dispersant 0.3-0.5 parts, BYK-011 defoaming agent 0.2-0.4 parts, BYK-358N leveling agent 0.2-0.4 parts, hydroxymethyl cellulose 0.3-0.5 parts, deionized water 15-20 parts; the functionalized hexagonal boron nitride tannic acid silica hybrid particles are made of the following components in parts by weight: hexagonal boron nitride 8-10 parts, tannic acid 3-5 parts, tetraethyl orthosilicate 2-6 parts, octadecyltrimethoxysilane 8.8-17.6 parts.

2. A method of preparing a corrosion protective coating for steel pipes according to claim 1, characterized by: Specifically comprising the following steps: S1, 100.0-110.0g castor oil, 20.0-30.0g trimethylolpropane are added into a reactor, dehydrated under nitrogen protection at 120℃ for 20-30min, then cooled to 80℃, 8.0-10.0g dimethylolpropionic acid and 25.0-30.0g acetone are added, stirred until dissolved, then slowly drop hexafluorohexane diisocyanate and 0.1g dibutyltin dilaurate catalyst, react at 80℃ until the NCO characteristic absorption peak disappears completely, remove acetone by distillation under reduced pressure, obtain fluorine-containing oil alcoholysis product; S2, the fluorine-containing oil alcoholysis product in step S1 is added into a reactor, heated to 70-80℃ under nitrogen protection, 20.0-30.0g hexamethylene diisocyanate is added, and 0.08g dibutyltin dilaurate is dropped, fully reacted for 70-90min, then 35.0-40.0g hydroxyethyl methacrylate is added for capping, continue to react for 50-60min, then the temperature of the reactor is reduced to 40-50℃, 1.0-1.2g dimethylolpropionic acid, 0.01-0.03g dibutyltin dilaurate are added, then heated to 70-80℃ and reacted for 120-150min, after the reaction is completed, the temperature is reduced to 60-65℃, 1.5-2.0g hydroxypropyl methacrylate is added and reacted for 120-150min, then 200mL sodium dodecyl sulfate aqueous solution with a mass fraction of 3.0-3.4%, 65.0-75.0g butyl acrylate are added into the reaction system, dispersed and emulsified for 100-120min, then the temperature is increased to 80-85℃, and the initiator solution is slowly dropped within 2h, the initiator solution is prepared by 0.8-1.0g ammonium persulfate and 40mL deionized water, and the reaction is carried out for 200-300min, finally the temperature is reduced to 40-45℃, ammonia solution is added to adjust the pH to 7.5-7.8, the filtrate is obtained, and a high-performance modified acrylic resin emulsion is obtained. S3, hydroxymethyl cellulose, deionized water into a high-speed mixer, stirring to complete dissolution at 300-500 rpm speed, then at 500-800 rpm speed, adding BYK-190 dispersant, titanium dioxide, functionalized hexagonal boron nitride tannic acid silica hybrid particles in turn for pre-dispersion treatment, adjust the stirring speed to 2000-2500 rpm, stirring time 10-20 min, then reduce the speed to 800-1000 rpm, adding the high performance modified acrylic resin emulsion, BYK-011 defoamer and BYK-358N leveling agent in step S2, keep the speed unchanged for 20-30 min dispersion treatment, finally the material is transferred to a horizontal sand mill for circulation grinding, ensure that the fineness of the particles is not more than 25 μm, to get the steel pipe anticorrosion coating.

3. The method for preparing the anti-corrosion coating for steel pipes according to claim 2, characterized in that: In step S1, the amount of hexafluorohexane diisocyanate added is 30.0-40.0 g.

4. The method for preparing the anti-corrosion coating for steel pipes according to claim 3, characterized in that: The preparation method of the functionalized hexagonal boron nitride tannic acid silica hybrid particle specifically comprises the following steps: (1) 0.8-1.0 g of hexagonal boron nitride is first ultrasonically dispersed in 100-200 mL of deionized water, then added to 50 mL of a sodium hydroxide solution with a mass fraction of 0.2-0.4% at pH 8.5, followed by the addition of tannic acid, and then reacted for 2-3 h under the conditions of 200-300 rpm magnetic stirring and a 50-60°C water bath, followed by centrifugation, and the precipitate being washed with anhydrous ethanol and deionized water in turn until the washing liquid is neutral and free of yellow or brown color, to obtain a wet-state hexagonal boron nitride@tannic acid precipitate; (2) The wet-state hexagonal boron nitride@tannic acid precipitate in step (1) is dispersed in 50 mL of anhydrous ethanol to form a dispersion liquid for use, while 100 mL of anhydrous ethanol, 20 mL of deionized water and 3-5 mL of ammonia water with a mass fraction of 25-28% are mixed to form a reaction solution for use, then the dispersion liquid is added to the reaction solution, and under the conditions of 200-300 rpm magnetic stirring and 30°C, tetraethyl orthosilicate is added using a constant-pressure dropping funnel, with the dropping speed controlled at 1-2 s per drop, after the dropping is completed, the reaction is continued for 12-24 h under the same conditions, centrifugation is performed, and the precipitate is washed with anhydrous ethanol and deionized water in turn for 3-5 times, and then dried in a vacuum oven at 60-80°C, ground, to obtain hexagonal boron nitride@tannic acid silica hybrid particles; (3) The hexagonal boron nitride@tannic acid silica hybrid particles in step (2) are ultrasonically dispersed in 200-300 mL of anhydrous ethanol, followed by the addition of octadecyltrimethoxysilane, and then reacted for 8-12 h under the conditions of 200-300 rpm magnetic stirring and a 50-60°C water bath, after the reaction is completed, centrifugation is performed, and the precipitate is washed with anhydrous ethanol and deionized water in turn until the washing liquid is neutral, and finally dried in a vacuum oven at 60-80°C, ground, to obtain functionalized hexagonal boron nitride tannic acid silica hybrid particles.

5. The method for preparing the anti-corrosion coating for steel pipes according to claim 4, characterized in that: In step (1), the amount of tannic acid added is 0.3-0.5 g.

6. The method for preparing the anti-corrosion coating for steel pipes according to claim 5, characterized in that: In step (2), the amount of tetraethyl orthosilicate added is 0.2-0.6 mL.

7. The method for preparing the anti-corrosion coating for steel pipes according to claim 6, characterized in that: In step (3), the octadecyltrimethoxysilane was added in an amount of 1.0-2.0 mL. In step (3), the octadecyltrimethoxysilane was added in an amount of 1.0-2.0 mL.

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