Waterproof and anticorrosive paint and preparation method thereof

Abstract

This invention relates to the field of high-performance coatings technology, specifically to a waterproof and anti-corrosion coating and its preparation method. This invention overcomes the problem of simultaneously achieving the high density required for waterproofing and the long-term anti-corrosion effect of coatings. The coating of this invention is composed of a mixture of component A and component B; polyvinyl alcohol is double-grafted with n-octanal and perfluorooctyltriethoxysilane, solving the problem of poor water resistance of polyvinyl alcohol at the molecular level; a synergistic anti-corrosion mechanism of physical barrier and chemical corrosion inhibition is constructed using graphene oxide loaded with benzotriazole; a highly dense interpenetrating network structure is constructed through organic bismuth catalysis; and stearic acid-modified nano-titanium dioxide and a specific hierarchical shear orientation process are used to achieve excellent waterproofing, salt spray resistance, and high adhesion of the coating.

Description

Technical Field

[0001] This invention relates to the field of high-performance coatings technology, specifically to a waterproof and anti-corrosion coating and its preparation method. Background Technology

[0002] In the field of modern industrial construction, steel and concrete structures are exposed to complex environments of acid rain, high humidity, salt spray, and chemical corrosion for extended periods, placing extremely high demands on the waterproofing and corrosion resistance of protective coatings. Traditional industrial anti-corrosion coatings, such as epoxy resin coatings, while offering acceptable corrosion resistance, are brittle after curing, have poor weather resistance, and are prone to blistering and peeling under prolonged water immersion. Polyurethane coatings, while possessing good toughness, are sensitive to the humidity of the application environment and are also more expensive.

[0003] Polyvinyl alcohol (PVA), a water-soluble polymer, possesses excellent film-forming properties, strong adhesion, superior gas barrier properties, and is environmentally friendly. However, the large number of hydrophilic hydroxyl groups in the PVA molecular chain results in extremely poor water resistance; its mechanical strength decreases significantly after water absorption, and it cannot prevent the penetration of water molecules and corrosive ions. This directly limits its application in industrial heavy-duty corrosion protection and waterproofing. To address this issue, conventional techniques typically employ simple physical blending or low-level crosslinking modification, but these often fail to simultaneously meet the requirements for high-density waterproofing and long-term corrosion protection.

[0004] In existing technologies, simply increasing the amount of filler to improve corrosion resistance often leads to increased coating porosity, which in turn reduces the waterproofing effect. Furthermore, traditional anti-corrosion pigments and fillers have poor dispersibility and are prone to agglomeration, forming corrosion channels. Therefore, developing a coating that achieves both excellent waterproofing and long-lasting corrosion resistance is a pressing technical challenge in the field of industrial building protection.

[0005] Therefore, a waterproof and anti-corrosion coating and its preparation method are proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a waterproof and anti-corrosion coating and its preparation method.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Unless otherwise specified, all parts in this invention are parts by weight.

[0008] This invention provides a method for preparing a waterproof and anti-corrosion coating, the method of which is as follows: Component A is prepared by mixing modified polyvinyl alcohol base material, modified graphene oxide, nanoparticle aqueous slurry, film-forming aid, defoamer and deionized water; Component B was prepared by mixing a hydrophilic modified polyisocyanate trimer, an organic bismuth catalyst, and propylene glycol methyl ether acetate. Component A and component B are mixed at a mass ratio of 8:1 to obtain a waterproof and anti-corrosion coating. The modified polyvinyl alcohol base material is obtained by reacting polyvinyl alcohol, n-octaldehyde, and perfluorooctyltriethoxysilane; Modified graphene oxide was obtained by modifying graphene oxide with benzotriazole; The nanoparticle aqueous slurry is obtained by mixing modified nano-titanium dioxide, a dispersant, and deionized water; the modified nano-titanium dioxide is obtained by modifying nano-titanium dioxide with stearic acid.

[0009] The preferred method for preparing modified polyvinyl alcohol base material is as follows: 100 parts of polyvinyl alcohol (PVA 17-99) are added to 400 parts of deionized water, heated to 95°C, stirred at 300 rpm for 3 hours, cooled to 60°C, 3 parts of concentrated hydrochloric acid (37 wt%) are added as a catalyst, and 12-18 parts of n-octanal (pre-mixed with 12 parts of anhydrous ethanol for dissolution) are added dropwise. The reaction is carried out at a constant temperature for 4 hours, and the pH of the system is adjusted to 4-5 using 5 wt% sodium hydroxide solution. 3-8 parts of perfluorooctyltriethoxysilane are dissolved in 10 parts of ethanol, and the pH is adjusted to 4 using acetic acid. After pre-hydrolyzing at 30°C for 30 minutes, the solution is added dropwise to the reaction system, and the reaction is continued at 60°C for 2 hours (grafting fluorine-containing groups). Finally, the pH is adjusted to 7-8 using sodium hydroxide solution to obtain the modified polyvinyl alcohol base material.

[0010] The preferred method for preparing modified graphene oxide is as follows: 2 parts of graphene oxide (average sheet diameter 5-10 μm, average thickness 0.8-1.2 nm, monolayer ratio >90%) are dispersed in 200 parts of ethanol aqueous solution (ethanol and deionized water volume ratio 1:1), ultrasonically dispersed at 400W for 1 h, 1 part of benzotriazole is added, and stirred at 50℃ and 500 rpm for 5.5-6.5 h. Corrosion inhibitor loading is achieved through non-covalent bonding by utilizing the π−π conjugated adsorption effect. The mixture is then filtered, washed, vacuum dried at 60℃ for 12 h, and ground in a planetary ball mill to obtain modified graphene oxide.

[0011] The preferred method for preparing modified nano-titanium dioxide is as follows: 100 parts of nano-titanium dioxide (rutile type, average particle size 20 nm) are added to 500 parts of anhydrous ethanol and ultrasonically dispersed for 30 min to obtain a nano-titanium dioxide dispersion; the temperature is raised to 70℃, 3-5 parts of stearic acid are dissolved in 50 parts of hot ethanol and added dropwise to the nano-titanium dioxide dispersion, and the reaction is carried out at 70-80℃ at a constant speed of 800 rpm for 3 h; after the reaction is completed, the mixture is filtered, washed three times with ethanol to remove unreacted stearic acid, and vacuum dried at 80℃ for 6 h, and ground to obtain modified nano-titanium dioxide; 5 parts of modified nano-titanium dioxide are mixed with 2 parts of polymeric dispersant BYK-190 and 10 parts of deionized water, and ground in a sand mill to a fineness of <20 μm to obtain an aqueous slurry of nanoparticles.

[0012] Preferably, the preparation method of component A is as follows: 70 parts of modified polyvinyl alcohol base material are added to a dispersion tank, stirring is started, and the speed is adjusted to 400 rpm. Then, 3 parts of modified graphene oxide, nanoparticle aqueous slurry, and 1 part of perfluorosilane modified nano-sized calcium carbonate powder are added sequentially (by introducing nano-alkaline filler as active acid capture sites, combined with a high-density isocyanate cross-linking network, an acidic isolation layer is constructed around the acetal bond, which effectively inhibits the reverse hydrolysis of the acetalization reaction and ensures the long-term hydrophobicity of the coating). The speed is adjusted to 2000-3000 rpm, and high-speed shear dispersion is performed for 30 min. The high shear force breaks the agglomeration of nanoparticles and ensures the exfoliation of graphene sheets. 2 parts of film-forming aid alcohol ester-12, 0.5 parts of defoamer BYK-024, and 0.5 parts of wetting agent BYK-348 are added. The speed is reduced to 200 rpm, and slow stirring is performed for 40-55 min. The mixture is then filtered to obtain component A.

[0013] Preferably, component B is prepared as follows: 18-25 parts of hydrophilic modified polyisocyanate trimer (Bayhydur 3100) and 5 parts of propylene glycol methyl ether acetate are added to a reaction vessel and stirred evenly. 0.5 parts of organic bismuth catalyst (bismuth neodecanoate, CAS: 34364-26-6) are added and mixed at 500 rpm for 20 min at room temperature (the role of the organic bismuth catalyst here is to catalyze the rapid crosslinking of isocyanate with the hydroxyl groups on polyvinyl alcohol after components A and B are mixed), thus obtaining component B.

[0014] In another aspect, the present invention provides a waterproof and anti-corrosion coating, which is prepared by any of the above preparation methods; the waterproof and anti-corrosion coating includes component A and component B; component A includes modified polyvinyl alcohol base material, modified graphene oxide, modified nano titanium dioxide, film-forming aid, defoamer and deionized water; component B includes hydrophilic modified polyisocyanate trimer, organic bismuth catalyst and propylene glycol methyl ether acetate.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention completely solves the problem of poor water resistance of traditional polyvinyl alcohol at the molecular structure level through a dual chemical modification method of n-octaldehyde acetalization and perfluorooctyltriethoxysilane grafting. The long carbon chain of n-octaldehyde effectively shields a large number of hydrophilic hydroxyl groups on the polyvinyl alcohol backbone, significantly reducing the water absorption rate of the resin; while the introduction of fluorinated side chains endows the coating with extremely low surface energy, making the coating surface exhibit a strong hydrophobic state similar to the "lotus leaf effect", significantly improving the water contact angle. This combination of internal hydrophobicity (long chain shielding) and external hydrophobicity (low surface energy of fluorosilane) allows the coating to maintain high mechanical strength and excellent adhesion even under long-term water immersion, effectively preventing coating swelling, softening and peeling caused by water molecule intrusion.

[0016] 2. This invention utilizes modified graphene oxide as a nano-container to load benzotriazole corrosion inhibitor, constructing a dual anti-corrosion mechanism of "physical barrier + chemical inhibition". The unique two-dimensional sheet structure of graphene oxide creates a labyrinthine path in the coating, greatly extending the penetration path of water, oxygen, and chloride ions, providing excellent physical shielding. When even trace amounts of corrosive media penetrate to the substrate surface, the loaded benzotriazole is released responsively, forming a dense adsorption film that inhibits anodic or cathodic reactions. This intelligent release mechanism of active substances complements the passive barrier effect of graphene oxide, significantly improving the coating's resistance to salt spray and electrochemical corrosion under damaged or long-term service conditions, and greatly extending the maintenance cycle of industrial facilities.

[0017] 3. This invention introduces an organic bismuth catalyst into a two-component system to efficiently catalyze the crosslinking reaction between the hydrophilically modified polyisocyanate trimer and the remaining hydroxyl groups of modified polyvinyl alcohol and silane hydrolysis products. The organic bismuth catalyst lowers the activation energy of the reaction, ensuring that the coating can undergo deep crosslinking even at room temperature or low temperature, forming a dense organic-inorganic hybrid interpenetrating polymer network. This high-density network structure not only further seals the micropores between polymer chains, significantly improving the density of the coating, but also endows the coating film with excellent hardness and wear resistance, solving the problem of poor weather resistance caused by low crosslinking degree after conventional PVA coating film formation.

[0018] 4. This invention employs stearic acid to organically modify the surface of nano-titanium dioxide, transforming it from hydrophilic to hydrophobic, thus significantly improving its dispersion stability in modified polyvinyl alcohol organic base materials. The hydrophobic nano-titanium dioxide can uniformly fill the gaps and micro-defects in the polymer molecular chains, acting as a "micropore sealant," reducing the porosity of the coating and blocking capillary water absorption channels. Furthermore, nano-titanium dioxide possesses semiconductor properties; under weak ultraviolet light or natural light irradiation in industrial environments, it can generate photogenerated electrons that inject into the metal substrate, causing the potential of the protected metal to shift negatively, entering the thermodynamically stable region, thereby providing a certain degree of photogenerated cathodic protection. This combination of physical filling and electrochemical protection further enhances the overall anti-corrosion performance of the coating.

[0019] 5. This invention employs a staged preparation process of "high-speed shearing followed by low-speed laminar flow," achieving a perfect synergy between material properties and processing technology. The high-speed shearing in the first stage provides strong fluid shear force, capable of breaking up the aggregates of modified graphene oxide and nano-titanium dioxide, ensuring that the nanofiller exists in a monodisperse state. The low-speed stirring in the second stage utilizes the laminar flow effect in fluid mechanics to induce the two-dimensional sheet-like graphene oxide to align in an orderly manner parallel to the substrate surface in the wet film. This directional alignment maximizes the path length of the "maze effect," resulting in improved impermeability compared to disordered alignment, thus enhancing the waterproof and corrosion-resistant consistency of the final coating. Attached Figure Description

[0020] Figure 1 The figures show the wear resistance test results of Examples 1-4 and Comparative Examples 7 and 9 of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1 This invention provides a waterproof and anti-corrosion coating and its preparation method, the technical solution of which is as follows:

[0023] Example 1 100 parts of polyvinyl alcohol were added to 400 parts of deionized water, heated to 95°C, and stirred at 300 rpm for 3 hours. The mixture was then cooled to 60°C, and 3 parts of concentrated hydrochloric acid (37 wt%) were added as a catalyst. 12 parts of n-octanal (pre-mixed with 12 parts of anhydrous ethanol for dissolution) were added dropwise at 800 rpm. The mixture was reacted at a constant temperature for 4 hours. The pH of the system was adjusted to 4-5 using a 5 wt% sodium hydroxide solution. Subsequently, 3 parts of perfluorooctyltriethoxysilane were dissolved in 10 parts of ethanol, and the pH was adjusted to 4 using acetic acid. After pre-hydrolyzing at 30°C for 30 minutes, the solution was added dropwise to the reaction system. The reaction was continued at 60°C for 2 hours. Finally, the pH was adjusted to 7-8 using sodium hydroxide solution to obtain the modified polyvinyl alcohol base material.

[0024] Two parts of graphene oxide were dispersed in 200 parts of an aqueous ethanol solution (ethanol and deionized water volume ratio of 1:1), ultrasonically dispersed at 400W for 1 h, one part of benzotriazole was added, and stirred at 50℃ and 500 rpm for 5.5 h. The mixture was then filtered, washed, and vacuum dried at 60℃ for 12 h. Finally, it was ground in a planetary ball mill for 1 h (ball-to-material ratio of 10:1, speed of 300 rpm) to obtain modified graphene oxide.

[0025] 100 parts of nano-titanium dioxide were added to 500 parts of anhydrous ethanol and ultrasonically dispersed for 30 min to obtain a nano-titanium dioxide dispersion. The temperature was raised to 70℃, and 3 parts of stearic acid were dissolved in 50 parts of hot ethanol (60℃) and added dropwise to the nano-titanium dioxide dispersion. The mixture was reacted at 70℃ and 800 rpm for 3 h. After the reaction was completed, the mixture was filtered and washed three times with ethanol to remove unreacted stearic acid. The mixture was vacuum dried at 80℃ for 6 h and ground at 400 rpm for 2 h to obtain modified nano-titanium dioxide. 5 parts of modified nano-titanium dioxide were mixed with 2 parts of polymeric dispersant BYK-190 and 10 parts of deionized water and ground in a sand mill to a fineness of <20 μm to obtain an aqueous slurry of nanoparticles.

[0026] 100 parts of nano-calcium carbonate (active light calcium carbonate, average particle size 50 nm) were added to 400 parts of anhydrous ethanol. The mixture was sheared at 5000 rpm for 20 min using a high-shear emulsifier, followed by ultrasonic dispersion at 600 W for 30 min. 10 parts of deionized water were added, and the pH of the system was adjusted to 9.5 with ammonia. The temperature was raised to 50 °C, and 4 parts of perfluorooctyltriethoxysilane were slowly added dropwise under continuous stirring. After the addition was completed, the temperature was raised to 70 °C and reacted at a constant temperature for 5 h. After centrifugation, the mixture was washed three times with anhydrous ethanol. The resulting filter cake was dried in a vacuum drying oven at 80 °C for 12 h. The dried solid block was added to a planetary ball mill and ground at 400 rpm for 1 h to obtain perfluorosilane-modified nano-sized calcium carbonate powder.

[0027] 70 parts of modified polyvinyl alcohol base material were added to a dispersion tank, and stirring was started at 400 rpm. Then, 3 parts of modified graphene oxide, nanoparticle aqueous slurry, and 1 part of perfluorosilane-modified nano-sized calcium carbonate powder were added sequentially. The stirring speed was adjusted to 2000 rpm, and high-speed shear dispersion was performed for 30 minutes. Next, 2 parts of film-forming aid alcohol ester-12, 0.5 parts of defoamer BYK-024, and 0.5 parts of wetting agent BYK-348 were added. The stirring speed was reduced to 200 rpm, and slow stirring was performed for 40 minutes. The mixture was then filtered to obtain component A. In a drying reactor, 18 parts of hydrophilic modified polyisocyanate trimer and 5 parts of propylene glycol methyl ether acetate were added and stirred until homogeneous. Then, 0.5 parts of organic bismuth catalyst bismuth neodecanoate were added, and the mixture was stirred at 500 rpm for 20 minutes at room temperature to obtain component B. Component A and component B were mixed at a mass ratio of 8:1 to obtain a waterproof and anti-corrosion coating.

[0028] Example 2 Referring to the preparation method and parameters of Example 1, the differences are as follows: when preparing the modified polyvinyl alcohol base material, the amount of n-octaldehyde is 14 parts and the amount of perfluorooctyltriethoxysilane is 4 parts; when preparing the modified graphene oxide, benzotriazole is added and stirred for 5.8 h; when preparing the modified nano titanium dioxide, the amount of stearic acid is 3.5 parts, and the temperature is raised to 75°C after the stearic acid solution is added dropwise; when preparing component A, the high-speed shear dispersion speed is 2300 rpm and the slow stirring time is 48 min.

[0029] Example 3 Referring to the preparation method and parameters of Example 1, the differences are as follows: when preparing the modified polyvinyl alcohol base material, the amount of n-octaldehyde is 16 parts and the amount of perfluorooctyltriethoxysilane is 6 parts; when preparing the modified graphene oxide, benzotriazole is added and stirred for 6.2 h; when preparing the modified nano titanium dioxide, the amount of stearic acid is 4 parts, and the temperature is raised to 75°C after the stearic acid solution is added dropwise; when preparing component A, the high-speed shear dispersion speed is 2600 rpm and the slow stirring time is 50 min.

[0030] Example 4 Referring to the preparation method and parameters of Example 1, the differences are as follows: when preparing the modified polyvinyl alcohol base material, the amount of n-octaldehyde is 18 parts and the amount of perfluorooctyltriethoxysilane is 8 parts; when preparing the modified graphene oxide, benzotriazole is added and stirred for 6.5 h; when preparing the modified nano titanium dioxide, the amount of stearic acid is 5 parts, and the temperature is raised to 80°C after the stearic acid solution is added dropwise; when preparing component A, the high-speed shear dispersion speed is 3000 rpm and the slow stirring time is 55 min.

[0031] Comparative Example 1 The preparation method and parameters of Example 1 were used, except that the polyvinyl alcohol was not modified.

[0032] Comparative Example 2 The preparation method and parameters of Example 1 are the same, except that during the polyvinyl alcohol modification process, no n-octaldehyde is added, and only perfluorooctyltriethoxysilane grafting is performed.

[0033] Comparative Example 3 The preparation method and parameters of Example 1 are the same, except that perfluorooctyltriethoxysilane is not added during the polyvinyl alcohol modification process, and only n-octanal acetalization is performed.

[0034] Comparative Example 4 The preparation method and parameters of Example 1 were used, except that the graphene oxide was not modified.

[0035] Comparative Example 5 The preparation method and parameters of Example 1 are the same, except that graphene oxide is not added and an equal amount of benzotriazole is directly dissolved in component A.

[0036] Comparative Example 6 The preparation method and parameters of Example 1 are the same, except that untreated nano-titanium dioxide is used.

[0037] Comparative Example 7 The preparation method and parameters are the same as in Example 1, except that no organic bismuth catalyst is added when preparing component B.

[0038] Comparative Example 8 The preparation method and parameters of Example 1 are the same, except that when preparing component A, high-speed shearing at 2500 rpm and slow stirring at low speed are not performed, and ordinary stirring at 500 rpm is used throughout the process.

[0039] Comparative Example 9 The preparation method and parameters of Example 1 are the same, except that component B is not used and only component A is used to form a film.

[0040] Experiment Example 1: Waterproof Performance Test After mixing component A and component B at a mass ratio of 10:1, mechanically stirring for 5 minutes to mature, then spraying, and testing after curing; Water contact angle: Using a contact angle meter, add 5 μL of deionized water and take the average value of 5 points; Water resistance: Tested according to Method B (immersion in room temperature water) in GB / T 1733-1993 "Determination of water resistance of paint film", and the time when the coating blistering, rusting or peeling occurs was recorded; The results are shown in Table 1.

[0041] Table 1 Waterproofing performance tests of Examples 1-4, Comparative Examples 1-3, Comparative Examples 6-7, and Comparative Example 9

[0042] Experiment Example 2: Corrosion Resistance Test Corrosion resistance (resistance to chemical media) is determined according to GB / T 9274-1998 "Determination of resistance to liquid media for paints and varnishes", using the immersion method; Acid resistance: Immersed in 5% H2SO4 solution; Alkali resistance: Immersed in 5% NaOH solution; Salt spray resistance was tested in accordance with the standard GB / T 1771-2007.

[0043] The results are shown in Table 2.

[0044] Table 2 Corrosion resistance test results of Examples 1-4 and Comparative Examples 2-6 and Comparative Example 8

[0045] Experiment Example 3: Hardness and Abrasion Resistance Test: Hardness: According to GB / T 6739-2006 "Determination of Hardness of Paints and Varnishes by Pencil Method"; Abrasion resistance: According to GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes", the weight loss after 500 revolutions using a JM-IV abrasion tester and a CS-10 grinding wheel with a load of 750g was measured. The results are shown in Table 3.

[0046] Table 3 Hardness and abrasion resistance tests of Examples 1-4 and Comparative Examples 7 and 9

[0047] As shown in Tables 1-3, in Examples 1-4, this invention overcomes the water solubility problem of polyvinyl alcohol from a molecular perspective through dual modification of internal blocking with n-octaldehyde and external grafting with fluorosilane, establishing a foundation for waterproofing. Secondly, by using modified graphene oxide loaded with benzotriazole, the physical labyrinth barrier of graphene oxide is combined with the chemical targeted passivation of benzotriazole, solving the problems of easy failure of single physical shielding and easy loss of single corrosion inhibitors. Furthermore, the "high shear-low laminar flow" process of this invention is not a conventional mixing process, but rather actively induces the parallel orientation of two-dimensional materials, maximizing material performance from a process perspective. Finally, Organobismuth preferentially forms transition state complexes with hydroxyl groups on modified polyvinyl alcohol, significantly reducing the activation energy of the -NCO / -OH reaction, enabling rapid crosslinking at room temperature or low temperature. Compared to traditional catalysts, organobismuth exhibits lower catalytic activity for the nucleophilic addition reaction of -NCO with water molecules, thus kinetically ensuring that the -NCO groups preferentially bind to the polymer matrix, minimizing polyurea formation and bubble expulsion, and ensuring high density and excellent adhesion of the coating. The low-temperature interpenetrating network constructed under organobismuth catalysis in this invention guarantees high density and high strength and toughness of the coating under industrial field conditions. Through multi-dimensional synergistic innovation, the coatings produced in this invention outperform the comparative examples.

[0048] In Comparative Example 1, the polyvinyl alcohol (PVA) was not modified. PVA contains a large number of hydrophilic hydroxyl groups, and before modification, it was instantly soluble or severely swollen upon contact with water. The coating failed instantly in the water resistance test, providing no anti-corrosion protection. In Comparative Example 2, no n-octaldehyde was added during the PVA modification process; surface modification with fluorosilanes was sufficient. The lack of shielding of the internal hydroxyl groups of PVA by the long carbon chain of n-octaldehyde (loss of internal hydrophobicity) allowed water molecules to easily penetrate the surface and enter the coating, leading to water absorption and swelling, and a sharp reduction in anti-corrosion lifespan. In Comparative Example 3, no perfluorooctyltriethoxysilane was added during the PVA modification process. The lack of low surface energy fluorinated groups prevented the contact angle from reaching a hydrophobic level, resulting in the loss of the "lotus effect." This easily led to the formation of a water film, accelerating the initial penetration of corrosive media. In Comparative Example 4, no modification was made to the graphene oxide. Although the graphene oxide provided a physical barrier, the lack of a loaded benzotriazole corrosion inhibitor meant that when the corrosive medium penetrated the graphene oxide layer and reached the substrate, a passivation film could not be formed for "self-repair," resulting in a shortened salt spray resistance time. In Comparative Example 5, an equal amount of benzotriazole was directly dissolved in component A, easily lost with water molecule migration, and dispersed disorderly. Lacking the carrier effect and "maze effect" of graphene oxide, the corrosion path was shortened, and the corrosion inhibitor could not form a high concentration release locally, resulting in a corrosion resistance life far lower than the synergistic system of graphene oxide loaded with benzotriazole. In Comparative Example 6, untreated nano-titanium dioxide was used. The hydrophilic nano-titanium dioxide severely agglomerated in the hydrophobic organic phase, not only failing to fill micropores but also creating defects and voids that became water molecule transport channels, leading to reduced water and corrosion resistance. In Comparative Example 7, without the addition of an organic bismuth catalyst, the isocyanate-hydroxyl reaction activity was low at room temperature. The lack of a catalyst resulted in extremely low crosslinking density, incomplete coating curing, extremely low hardness, and a porous internal structure, making it highly susceptible to water intrusion. In Comparative Example 8, component A was prepared using ordinary stirring at 500 rpm throughout the process. The lack of shearing caused the graphene oxide and titanium dioxide to agglomerate. The lack of slow laminar flow stirring resulted in the sheet-like graphene oxide being arranged randomly rather than in parallel within the coating, significantly reducing the "maze effect." Although the material composition was the same, the difference in microstructure led to reduced corrosion resistance. In Comparative Example 9, only component A formed a film. The coating was thermoplastic, lacking an interpenetrating network structure, and swelled and dissolved upon contact with water, exhibiting extremely poor hardness and completely lacking industrial application value.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a water-resistant and rot-proof paint, characterized by: The preparation method is as follows: Component A is prepared by mixing modified polyvinyl alcohol base material, modified graphene oxide, nanoparticle aqueous slurry, film-forming aid, defoamer and deionized water; Component B was prepared by mixing a hydrophilic modified polyisocyanate trimer, an organic bismuth catalyst, and propylene glycol methyl ether acetate. The waterproof and anti-corrosion coating is obtained by mixing component A and component B at a mass ratio of 8:

1. The modified polyvinyl alcohol base material is obtained by reacting polyvinyl alcohol, n-octaldehyde, and perfluorooctyltriethoxysilane. The preparation method of the modified polyvinyl alcohol base material is as follows: 100 parts of the polyvinyl alcohol are added to 400 parts of deionized water and stirred, 3 parts of concentrated hydrochloric acid are added, 12-18 parts of n-octaldehyde are added dropwise to react, the pH value is adjusted, and then 3-8 parts of perfluorooctyltriethoxysilane are added dropwise to continue the reaction. The pH value is adjusted with sodium hydroxide solution to obtain the modified polyvinyl alcohol base material. The modified graphene oxide was obtained by modifying graphene oxide with benzotriazole; The nanoparticle aqueous slurry is obtained by mixing modified nano-titanium dioxide, a dispersant, and deionized water; the modified nano-titanium dioxide is obtained by modifying nano-titanium dioxide with stearic acid.

2. The method for preparing a water-proof and anti-corrosion paint according to claim 1, characterized in that: The modified graphene oxide is prepared as follows: the graphene oxide is dispersed in an aqueous ethanol solution by ultrasonic dispersion, benzotriazole is added and stirred to react, filtered, washed, vacuum dried, and ground to obtain the modified graphene oxide.

3. The method of claim 1, wherein the water-proof and anti-corrosion paint is prepared by mixing the water-proof and anti-corrosion paint composition with a solvent. The modified nano-titanium dioxide is prepared as follows: nano-titanium dioxide is added to anhydrous ethanol and ultrasonically dispersed to obtain a nano-titanium dioxide dispersion; the temperature is raised, the stearic acid is dissolved in hot ethanol and added dropwise to the nano-titanium dioxide dispersion, and the reaction is carried out at a constant temperature of 70-80℃; after the reaction is completed, the mixture is filtered, washed, vacuum dried, and ground to obtain the modified nano-titanium dioxide.

4. The method of claim 1, wherein the water-proof and anti-corrosion paint is prepared by mixing the water-proof and anti-corrosion paint composition with a solvent. The preparation method of component A is as follows: the modified polyvinyl alcohol base material and deionized water are added to a dispersion tank, stirring is started, the modified graphene oxide and the nanoparticle aqueous slurry are added in sequence, and the rotation speed is increased for shear dispersion; the film-forming aid and the defoamer are added, the rotation speed is reduced for stirring, and the material is filtered out to obtain component A.

5. The method for preparing a waterproof and anti-corrosion coating according to claim 1, characterized in that: The preparation method of component B is as follows: the hydrophilic modified polyisocyanate trimer and the propylene glycol methyl ether acetate are added to a reaction vessel and stirred evenly. The organic bismuth catalyst is then added and mixed at room temperature to obtain component B.

6. A waterproof and anti-corrosion coating, characterized in that: The waterproof and anti-corrosion coating is prepared by the preparation method according to any one of claims 1-5; the waterproof and anti-corrosion coating includes component A and component B; component A includes modified polyvinyl alcohol base material, modified graphene oxide, nanoparticle aqueous slurry, film-forming aid, defoamer and deionized water; component B includes hydrophilic modified polyisocyanate trimer, organic bismuth catalyst and propylene glycol methyl ether acetate.

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