Universal concrete surface epoxy sealing coating and preparation method thereof

Abstract

The invention discloses a universal concrete surface epoxy sealing coating, the coating comprises a component A and a component B, the weight ratio of the component A to the component B is (2-4): 1, the component A comprises epoxy resin, a reactive diluent, pigment filler, a defoaming agent, a dispersing agent, a leveling agent and an anti-settling agent, and the component B comprises a curing agent, an accelerant and a coupling agent. The epoxy sealing coating disclosed by the invention can meet the protection requirements of concrete structures in different environments.

Description

Technical Field

[0001] The invention relates to the technical field of concrete materials, and in particular to a method for preparing a universal epoxy sealing coating on a concrete surface. Background Art

[0002] As one of the most widely used structural materials in modern architecture, concrete plays a vital role in various construction projects. However, concrete structures face numerous challenges in actual use. These challenges severely impact the durability and service life of concrete, increase maintenance costs, and even threaten the safety of building structures.

[0003] In humid environments, moisture continuously penetrates concrete. The pores and capillaries within concrete provide pathways for moisture, and long-term moisture accumulation increases the humidity within the concrete. When steel bars are present within the concrete, moisture forms a film on the surface, triggering electrochemical corrosion. Corroded steel bars expand in volume, exerting intense pressure on the surrounding concrete, causing cracking and spalling, severely weakening the structure's bearing capacity.

[0004] Concrete structures in coastal areas are exposed to high concentrations of chloride ions for long periods of time. Seawater contains large amounts of chloride ions, which can penetrate the passivation film on the concrete surface, destroying the protective film on the steel bars and accelerating corrosion. Statistics show that chloride ion corrosion shortens the service life of concrete structures in coastal areas by 30%-50% compared to normal environments.

[0005] In cold northern regions, concrete structures are subject to frequent freeze-thaw cycles. When temperatures drop, water trapped in the concrete's pores freezes and expands, exerting immense pressure on the concrete's internal structure. When temperatures rise and the ice melts, the concrete's internal structure gradually deteriorates from repeated expansion and contraction, leading to surface cracks and falling blocks. After repeated freeze-thaw cycles, the concrete's strength decreases significantly, seriously compromising its structural stability.

[0006] Concrete structures in industrial environments face corrosion from various chemicals. For example, near chemical plants, concrete may be exposed to acidic gases, alkaline solutions, or salts. These chemicals react with concrete components, damaging their internal structure and reducing their strength and durability. Some acidic gases dissolve in water to form acid rain, which gradually corrodes the concrete surface. Alkaline solutions react with components in concrete, such as silica, causing a decrease in the concrete's adhesion.

[0007] Although there are many types of concrete protective coatings currently available on the market, they all have certain limitations. Traditional organic coatings, such as alkyd resin coatings and acrylic resin coatings, although the construction process is relatively simple and the cost is low, their water resistance and weather resistance are poor. Under the influence of natural factors such as long-term sunlight exposure, rain erosion and temperature changes, the coating is prone to aging, fading, blistering and falling off, and cannot provide long-lasting and effective protection for concrete. The water resistance of these coatings is usually less than a few hundred hours, and in harsh environments, the service life may only be a few years. Some high-performance coatings, such as fluorocarbon coatings, have excellent weather resistance, corrosion resistance and self-cleaning properties, but they are expensive. The raw materials of fluorocarbon coatings are relatively expensive, and the construction process requires strict environmental control and professional technicians to operate, and the construction cost is also high. This greatly limits the large-scale application of fluorocarbon coatings, especially for some construction projects with limited budgets, which are difficult to bear the high cost.

[0008] Furthermore, existing protective coatings lack versatility, making them difficult to adapt to the protective needs of concrete structures in diverse regions and environments. Some coatings are ineffective at resisting chloride ion penetration and are unable to effectively protect concrete structures in marine environments. Some coatings also have difficulty curing in low-temperature environments, rendering their protective properties ineffective. In cold regions, when temperatures fall below 5°C, some conventional coatings cure extremely slowly or even fail to cure, preventing them from forming a complete protective film and failing to provide the desired protective effect.

[0009] Prior art CN202111629766.2 A concrete curing agent, a curing coating and a preparation method thereof, the concrete curing agent includes a hardener and a hydrophobic agent, and the raw materials of the hardener include, by weight, 0.1-10 parts of fluorosilicate and 100 parts of water, and the raw materials of the hydrophobic agent include: 0.1-10 parts of alkali catalyst, 1-10 parts of silane coupling agent, 0.1-10 parts of hydrogenated silicone oil, 5-10 parts of cross-linking agent, 10-100 parts of silica sol and 100-1000 parts of water. The technical solution of the present invention can significantly improve the surface strength, hardness and hydrophobicity, impermeability and freeze-thaw resistance of concrete before and after hardening, and effectively improve the service life of concrete structures. The prior art adds a silane coupling agent, but the effect is not rich enough.

[0010] Prior art CN202411288463.2, a gradient composite protective coating for hydraulic concrete and its preparation method, relates to the field of protective coating technology. The gradient composite protective coating for hydraulic concrete includes an isolation layer and a protective layer; the isolation layer is a YEP toughened epoxy putty isolation layer; the protective layer is a high-performance elastic coating or a high-toughness coating. The base concrete-isolation layer-protective layer forms a performance gradient of rigidity-toughness-elasticity / high toughness in the vertical direction of the base surface, forming a performance gradient composite coating structure. The role of the tough isolation layer is to isolate the water seepage channel of the porous concrete, prevent the elastic coating from bulging and cracking, and provide a good base surface condition for the elastic coating, and seal the surface defects and pores of the concrete; the role of the elastic coating is to provide all-round medium isolation protection for the concrete, and can provide functional effects such as surface roughness reduction and impact resistance for water supply projects. The performance gradient formed by this prior art cannot meet the use of various environments.

[0011] In summary, the development of an epoxy sealant coating for concrete surfaces with excellent versatility, superior protective properties, and a cost-effective method for its preparation is urgently needed. This coating needs to provide long-term, stable protection for concrete structures in diverse environmental conditions, such as humidity, high salt levels, cold weather, and chemical corrosion. It also needs to be low-cost and easy to apply to meet the practical needs of the construction industry. Summary of the Invention

[0012] In response to the shortcomings of the existing technology, the present invention provides a universal epoxy sealing coating for concrete surface and a preparation method thereof. Through innovative formula design and advanced preparation technology, it solves various problems existing in existing concrete protective coatings, significantly improves the comprehensive performance of the coating, effectively extends the service life of concrete structures, and reduces maintenance costs.

[0013] To achieve the above objectives, the present invention is implemented through the following technical scheme: a universal epoxy sealing coating for concrete surface, the coating comprising component A and component B, the weight ratio of component A to component B being (2-4):1, the component A comprising epoxy resin, reactive diluent, pigment, filler, defoamer, dispersant, leveling agent, anti-settling agent, the component B comprising curing agent, accelerator, coupling agent, diluent.

[0014] Furthermore, component A comprises, by weight, 40 to 60 parts of epoxy resin, 5 to 15 parts of active diluent, 30 to 50 parts of pigment and filler, 0.5 to 2 parts of defoaming agent, 1 to 3 parts of dispersant, 0.5 to 2 parts of leveling agent, and 1 to 3 parts of anti-settling agent.

[0015] Furthermore, component B comprises, by weight, 50 to 90 parts of curing agent, 1 to 5 parts of accelerator, 1 to 3 parts of coupling agent, and 5 to 10 parts of diluent.

[0016] Furthermore, the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin or novolac epoxy resin.

[0017] Furthermore, the active diluent is one or more of vinyl cyclohexene diepoxide, benzyl glycidyl ether or propylene glycol diglycidyl ether.

[0018] Furthermore, the pigment and filler is any one of titanium dioxide or talc.

[0019] Furthermore, the defoaming agent is an organosilicon defoaming agent, a polyether defoaming agent or a mixture of the two.

[0020] Furthermore, the dispersant is a polymer dispersant.

[0021] Furthermore, the leveling agent is any one of an organic silicon leveling agent or a fluorocarbon leveling agent.

[0022] Furthermore, the anti-settling agent is one or more of bentonite, fumed silica or hydrogenated castor oil.

[0023] Furthermore, the curing agent is one or more of an aliphatic polyamine curing agent, an alicyclic polyamine curing agent or a polyamide curing agent.

[0024] Furthermore, the accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine or DMP-30.

[0025] Furthermore, the coupling agent is a silane coupling agent.

[0026] Furthermore, before construction, component A and component B are mixed according to the specified weight ratio and stirred evenly for 5 to 10 minutes; after the coating is completed, it is cured at 20-30°C for 24 to 48 hours.

[0027] A method for preparing a universal epoxy sealing coating on a concrete surface comprises the following steps:

[0028] Preparation of component A

[0029] Pre-dispersion stage: Add epoxy resin and active diluent into the stirring kettle, start stirring, control the stirring speed at 300-500r / min, and stir for 5-10 minutes;

[0030] Grinding and dispersing stage: add defoamer, dispersant, pigment, filler, and anti-settling agent in sequence, continue stirring, increase the stirring speed to 800-1200r / min, stir for 15-30min, and then grind with a sand mill to control the grinding fineness to below 30μm;

[0031] Paint mixing stage: transfer the ground slurry to the paint mixing kettle, add leveling agent, adjust the stirring speed to 500-800r / min, and stir for 10-15 minutes to mix all the ingredients evenly to obtain component A;

[0032] Preparation of component B

[0033] Add curing agent into the stirring tank, start stirring, and control the stirring speed at 200-400r / min;

[0034] Add the accelerator, coupling agent and diluent in sequence and continue stirring for 10 to 15 minutes to obtain component B.

[0035] Beneficial effects

[0036] The present invention provides a method for preparing a universal epoxy sealing coating on concrete surfaces. Compared with the prior art, it has the following advantages:

[0037] Good versatility: The epoxy sealing coating of the present invention can adapt to the protection needs of concrete structures in different environments. In the marine environment, the shielding structure formed by the talc powder and precipitated barium sulfate in the coating and the enhanced adhesion of the silane coupling agent can effectively resist the penetration of chloride ions and prevent the corrosion of steel bars in the concrete. According to tests, after immersion in a 3.5% sodium chloride solution for 1000 hours, the chloride ion penetration of the coating was only 1 / 5 of that of traditional coatings, which can significantly extend the service life of concrete structures in marine environments. In cold areas, the flexibility and good adhesion of the coating can withstand the freeze-thaw cycle of concrete and is not prone to falling off, cracking, etc. After 50 freeze-thaw cycle tests at -20℃ to 20℃, the integrity of the coating remained good, with no obvious peeling and cracking, while traditional coatings showed large-scale peeling after 20 freeze-thaw cycles. In industrial environments, the selection of epoxy resin and curing agent gives it good chemical corrosion resistance and can resist erosion by various chemicals. The coating can maintain stable performance for acid and alkali solutions with different pH values. After immersion in a solution with a pH value of 2-12 for 30 days, the hardness and adhesion of the coating change by less than 10%.

[0038] Excellent Protective Performance: Through the careful selection of epoxy resin, pigments, fillers, and curing agents, the coating exhibits excellent water resistance, weather resistance, and resistance to chloride ion penetration. Experiments have shown that the coating's water absorption rate is less than 5%. After more than 1,000 hours of salt spray testing, the coating showed no noticeable blistering or shedding, effectively protecting the concrete structure from external corrosion. In contrast, traditional coatings exhibited blistering and rust after just 500 hours of salt spray testing. Furthermore, the coating exhibits excellent weather resistance. After 2,000 hours of artificial aging testing, the coating's color difference changed by less than 3, and its chalking grade was 0, maintaining its excellent appearance and performance.

[0039] Improved Adhesion: The use of silane coupling agents forms a chemical bond between the coating and the concrete surface, significantly enhancing adhesion between the coating and the substrate. Testing has shown that the coating's adhesion reaches Level 1 or higher (according to GB / T9286-1998, "Scratch Test for Paints and Varnishes"), ensuring that the coating will not easily fall off during long-term use. In actual engineering applications, the coating maintains a firm adherence to the concrete surface, providing continuous protection even in harsh conditions such as strong winds and heavy rain.

[0040] Moderate Cost: The raw materials used in this invention are all commonly available and relatively low in cost. The simple preparation process also allows for easy industrial production. This reduces production costs while maintaining protective performance, resulting in excellent economic benefits and market competitiveness. Compared to high-performance fluorocarbon coatings, this coating costs 30%-50% less, while achieving protective performance comparable to or approaching that of fluorocarbon coatings, making it ideal for large-scale concrete protection projects.

[0041] Multifunctional synergistic effect: The present invention achieves a multifunctional synergistic effect by carefully screening and matching various ingredients. For example, the silane coupling agent can not only enhance the adhesion between the coating and the concrete, but the silanol groups formed after its hydrolysis can also react with other components in the coating to enhance the overall stability and water resistance of the coating. In a humid environment, the silanol groups can form hydrogen bonds with water molecules to prevent further penetration of moisture, while enhancing the adhesion between the coating and the concrete and preventing the coating from falling off. Nano-scale pigments and fillers such as nano-titanium dioxide can improve the weather resistance of the coating while its photocatalytic properties can decompose surface organic pollutants and achieve a self-cleaning function. Under sunlight, nano-titanium dioxide can generate electron-hole pairs. These electron-hole pairs can react with oxygen and water in the air to generate hydroxyl radicals with strong oxidizing properties. Hydroxyl radicals can decompose organic pollutants adsorbed on the surface of the coating, such as dust, oil, etc., to keep the coating surface clean. In addition, by optimizing the proportion of each component, the coating can exert a good protective effect in different environments, thereby improving versatility. For marine environments, the proportion of ingredients with anti-chloride ion penetration function is increased; for cold regions, the formula is adjusted to improve the flexibility and low-temperature curing performance of the coating.

[0042] Gradient functional structure: In order to construct a gradient functional structure, during the preparation process, by controlling the curing reaction conditions and adding special gradient regulators (such as specific surfactants or polymers), the coating forms a structure with gradually changing properties from the inside to the outside during the curing process. The inner layer close to the concrete surface has a relatively high curing agent content, forming a tight cross-linked structure and enhancing the adhesion to the concrete. This is because the high curing agent content can promote the chemical bonding between the epoxy resin and the concrete surface, so that the coating is tightly bonded to the concrete and not easy to fall off. The outer layer has relatively high content of epoxy resin and active diluent, which makes the coating surface have better flexibility and stain resistance. The flexibility of the outer layer can make the coating less likely to crack when subjected to external impact or deformation, and the stain resistance can reduce the adhesion of pollutants such as dust and oil on the coating surface, maintaining the beauty and protective performance of the coating. This gradient structure design effectively improves the overall performance of the coating, enabling it to better play a protective role in different environments. In an environment with strong wind and sand, the flexibility of the outer layer can resist the wear of wind and sand, and the anti-fouling property can reduce the adhesion of sand and dust; in a chemical corrosion environment, the tightly cross-linked structure of the inner layer can effectively block the penetration of chemical substances and protect the concrete structure.

[0043] Intelligent slow-release anti-seepage system: The construction of the intelligent slow-release anti-seepage system is to introduce microcapsules containing corrosion inhibitors and penetration enhancers into the coating. The core material of the corrosion inhibitor microcapsule is a high-efficiency corrosion inhibitor, such as a molybdate corrosion inhibitor, and the wall material is a polymer material that is sensitive to environmental factors (such as pH value and chloride ion concentration). When there is a risk of corrosion in the environment where the coating is located, such as a decrease in pH value or an increase in chloride ion concentration, the microcapsule wall material responds and releases corrosion inhibitors to inhibit the corrosion of steel bars in the concrete. In a marine environment, when chloride ions penetrate into the coating, the microcapsule wall material will sense the change in chloride ion concentration and release corrosion inhibitors. The corrosion inhibitors can form a protective film on the surface of the steel bars to prevent chloride ions from reacting with the steel bars and prevent the steel bars from rusting. When the coating is subjected to pressure from water or other corrosive media, the penetration enhancer microcapsules release the enhancer to promote the coating to fill the pores in the concrete and improve the anti-seepage performance. In a humid environment, moisture puts pressure on the coating, and the penetration enhancer microcapsules will release enhancers, which can reduce the surface tension of the coating, making it easier for the coating to penetrate into the pores of the concrete, filling the pores, improving the impermeability of the coating, and effectively preventing moisture from further penetrating into the interior of the concrete. DETAILED DESCRIPTION

[0044] The present disclosure will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the relevant content, rather than to limit the present disclosure.

[0045] A universal epoxy sealing coating for concrete surface consists of component A and component B, wherein the weight ratio of component A to component B is (2-4):1.

[0046] Component A, calculated by weight, comprises:

[0047] Epoxy resin: 40-60 parts, using one or more of bisphenol A, bisphenol F, or novolac epoxy resins. Bisphenol A epoxy resin has a high epoxy value, resulting in a hard and wear-resistant coating after curing. Bisphenol F epoxy resin, with its relatively low benzene ring content, imparts greater flexibility and water resistance to the coating. Novolac epoxy resin offers excellent heat and chemical resistance. By properly selecting and combining these epoxy resins, the coating can be optimized for chemical stability, mechanical properties, and adhesion, tailored to the specific application environment and requirements.

[0048] Reactive diluent: 5-15 parts, such as one or more of vinyl cyclohexene diepoxide, benzyl glycidyl ether, or propylene glycol diglycidyl ether. Reactive diluents can effectively reduce the viscosity of the epoxy resin, improving the coating's application properties and making it easier to apply evenly, reducing dripping and missing coatings. Furthermore, reactive diluents participate in the curing reaction without affecting the coating's final properties, ensuring the coating's quality and protective effectiveness.

[0049] Pigments and fillers: 30-50 parts, including 10-20 parts of titanium dioxide. As a white pigment, titanium dioxide offers high hiding power and whiteness, significantly enhancing the decorative qualities of the coating and adding a more aesthetically pleasing finish to the concrete surface. It also enhances the coating's weather resistance, resists UV damage, and slows aging. Talc: 10-20 parts. Its flaky structure forms an effective barrier within the coating. During the film-forming process, the overlapping flaky particles of talc act like a multi-layered barrier, effectively blocking the penetration of moisture, oxygen, and corrosive media into the substrate. This extends the path these substances take to reach the substrate, thereby slowing corrosion. Precipitated barium sulfate: 10-10 parts. Precipitated barium sulfate is chemically stable and improves the coating's hardness and wear resistance, enhancing its physical properties and making it more durable.

[0050] Defoamer: 0.5-2 parts, using silicone defoamers, polyether defoamers, or a combination of the two. During the coating preparation, stirring, and application process, a large number of bubbles are generated. If not promptly eliminated, these bubbles will remain in the coating, forming pores or voids, affecting the coating's density and protective properties. Silicone defoamers offer rapid defoaming and long-lasting foam suppression; polyether defoamers are highly compatible in water-based systems and are less likely to produce defects such as shrinkage cavities. By selecting the appropriate defoamer or its combination, bubbles generated during stirring and application can be effectively eliminated, ensuring coating quality.

[0051] Dispersant: 1-3 parts. Use a polymeric dispersant, such as a polyacrylate dispersant. Polymeric dispersants can evenly disperse pigments and fillers in the coating system through steric hindrance and electrostatic repulsion. During the coating preparation process, inhomogeneous dispersion of pigments and fillers can lead to uneven coating color and unstable performance. Dispersants prevent pigments and fillers from agglomerating, improving the coating's stability and storage properties, ensuring optimal performance during use.

[0052] Leveling agent: 0.5-2 parts, such as a silicone leveling agent or fluorocarbon leveling agent. Silicone leveling agents can reduce the surface tension of the coating, allowing for good leveling during application, reducing defects like orange peel and brush marks, and resulting in a smoother, flatter coating surface. Fluorocarbon leveling agents, with their lower surface tension, can significantly improve the coating's flatness and gloss, further enhancing its decorative and protective properties.

[0053] Anti-settling agent: 1-3 parts of one or more of bentonite, fumed silica, or hydrogenated castor oil. These agents increase the thixotropy of the coating and prevent pigments and fillers from settling during storage. Settling of pigments and fillers during storage can cause the coating to separate, requiring re-stirring before use, making application more difficult. Anti-settling agents ensure uniformity and maintain good performance during storage and application.

[0054] Component B, calculated by weight, comprises:

[0055] Curing agent: 50-90 parts, one or more of aliphatic polyamine curing agent, alicyclic polyamine curing agent, or polyamide curing agent. Aliphatic polyamine curing agents offer fast curing speed and high strength; alicyclic polyamine curing agents provide coatings with excellent weather resistance and chemical resistance; polyamide curing agents impart excellent flexibility and adhesion. Choosing the appropriate curing agent or combination based on the specific application environment and requirements ensures the coating has excellent curing performance and overall performance.

[0056] Accelerator: 1-5 parts, such as one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine, or DMP-30. Accelerators can accelerate the curing reaction, shorten the curing time, and improve production efficiency. In actual construction, prolonged curing time can affect construction progress and increase construction costs. The addition of an accelerator can accelerate the curing speed while maintaining coating performance, allowing the coating to meet application requirements more quickly.

[0057] Coupling agent: 1-3 parts silane coupling agent, such as γ-aminopropyltriethoxysilane or γ-glycidoxypropyltrimethoxysilane, is used. Silane coupling agents form a chemical bond between the coating and the concrete surface, enhancing adhesion between the coating and the substrate. Concrete surfaces contain numerous pores and tiny cracks, and coupling agents can penetrate these pores and cracks, reacting chemically with concrete components while cross-linking with the epoxy resin in the coating. This creates a strong transition layer between the coating and concrete, significantly improving the coating's adhesion and anti-stripping properties.

[0058] Diluent: 5-10 parts, such as component A, further adjust the viscosity of component B to ensure that the two components are fully blended and pre-reacted.

[0059] A method for preparing a universal epoxy sealing coating on a concrete surface comprises the following steps:

[0060] Preparation of component A

[0061] Pre-dispersion stage: Add epoxy resin and reactive diluent to a stirred tank and start stirring at a speed of 300-500 rpm for 5-10 minutes to thoroughly mix the epoxy resin and reactive diluent. This stage aims to achieve a preliminary mixing of the epoxy resin and reactive diluent, laying the foundation for subsequent dispersion and reaction. Controlling the stirring speed and time is crucial: too low a speed may result in uneven mixing, while too high a speed may generate excessive bubbles.

[0062] Grinding and Dispersion Stage: Defoamer, dispersant, pigments and fillers (titanium dioxide, talc, precipitated barium sulfate), and anti-settling agent are added in sequence. Stirring is continued, increasing the stirring speed to 800-1200 rpm for 15-30 minutes. The mixture is then ground in a sand mill, maintaining a grinding fineness below 30 μm to ensure full dispersion of the pigments and fillers. During this stage, various additives and pigments and fillers are gradually added and thoroughly stirred. High-speed stirring allows for initial dispersion of the pigments and fillers within the coating system, while sand milling further refines the pigment and filler particles, ensuring their uniform dispersion throughout the coating and improving its stability and performance. Controlling the grinding fineness is crucial to coating quality. Inadequate grinding fineness can result in a rough surface and poor gloss, impacting the coating's protective properties.

[0063] Paint letdown: Transfer the ground slurry to a paint letdown kettle, add a leveling agent, adjust the stirring speed to 500-800 rpm, and stir for 10-15 minutes to evenly mix all ingredients to obtain component A. The primary purpose of the paint letdown stage is to ensure uniform mixing of the other ingredients while fully utilizing the leveling agent, adjusting the coating's leveling properties and ensuring a smooth, even coating during application. The stirring speed and time should be carefully considered, taking into account the properties of the leveling agent and the overall performance of the coating to achieve optimal leveling.

[0064] Preparation of component B

[0065] Add the curing agent to the stirring kettle and start stirring at a speed of 200-400 rpm. First, add the curing agent and stir to ensure it is evenly dispersed, preparing for the subsequent addition of other ingredients. The stirring speed should not be too high to avoid excessive bubbles, which may affect the performance of the curing agent.

[0066] Add the accelerator, coupling agent, and diluent in sequence and continue stirring for 10-15 minutes to thoroughly mix the ingredients to obtain Component B. The order of adding the accelerator and coupling agent and the stirring time have a significant impact on the performance of Component B. The accelerator accelerates the curing reaction, while the coupling agent enhances the adhesion of the coating to the concrete. Thorough stirring ensures that they are evenly mixed with the curing agent and fully exert their respective effects.

[0067] Coating application

[0068] Before application, mix components A and B according to the specified weight ratio and stir thoroughly for 5-10 minutes. The uniformity of the mixing of components A and B directly affects the curing effect and performance of the coating. Stirring too short a time may result in uneven mixing of the two components, affecting the quality of the coating. Stirring too long may increase application costs and may cause the coating to cure prematurely, affecting application operations.

[0069] Pre-treat the concrete surface to remove impurities such as oil, dust, and loose layers, ensuring the surface is smooth, dry, and clean. Cracks or holes in the concrete surface require repair. Pre-treating the concrete surface is crucial for ensuring coating adhesion and protective effectiveness. Impurities such as oil and dust can hinder the adhesion of the coating to the concrete, while loose layers can affect the coating's stability. Repairing cracks and holes ensures the integrity of the coating and prevents moisture and corrosive media from penetrating the concrete through these defects.

[0070] Apply the mixed coating evenly to the concrete surface by brushing, spraying, or rolling. The coating thickness should be controlled between 0.1 and 0.5 mm, depending on actual needs. During application, ensure uniform coverage without leaks or drips. Different application methods are suitable for different scenarios. Brushing is suitable for small areas or areas requiring a thicker coating. Spraying is highly efficient and suitable for large areas. Rolling can create a smoother coating surface. Regardless of the application method, ensure that the coating is uniform and thick enough to maintain its protective properties.

[0071] After the coating is applied, it should be cured at room temperature (20-30°C) for 24 to 48 hours, or appropriate curing conditions, such as heat curing, should be selected based on the actual situation to ensure that the coating is fully cured and achieves optimal performance. Curing conditions have a significant impact on the performance of the coating. Room temperature curing is simple to operate, but the curing time is longer; heat curing can speed up the curing process, but requires additional equipment and energy. In actual construction, appropriate curing conditions should be selected based on factors such as the construction environment and construction period requirements to ensure that the coating can be fully cured and form a protective film with good performance.

[0072] In the preparation method, precise control of the stirring speed, time, and temperature at each stage, as well as strict control of the order of raw material addition, ensures full reaction and uniform mixing of the ingredients, thereby guaranteeing the stability and consistency of the coating's performance. Regarding the construction of the gradient functional structure, during the curing process, the rate of change of the ambient temperature and humidity is controlled, in conjunction with the action of a gradient modulator, to guide the coating to form the desired gradient structure. For example, in the initial curing phase, the ambient temperature is appropriately elevated to promote the curing reaction within the coating, forming a compact inner layer structure; in the later stages of curing, the temperature is lowered to slow the curing of the outer layer, allowing it to maintain a certain degree of flexibility. For the intelligent sustained-release anti-seepage system, the ratio of core and wall materials, as well as the preparation process parameters, are strictly controlled during the preparation of the microcapsules to ensure their stability and responsiveness. By adjusting the composition and thickness of the wall material, the microcapsules' sensitivity to environmental factors and the release rate can be controlled, allowing the corrosion inhibitor and penetration enhancer to be released promptly when needed, achieving optimal protective effectiveness. During the coating application phase, the coating viscosity and application parameters are adjusted according to the different application methods and concrete surface conditions to ensure the coating's quality and protective effectiveness. For concrete with rough surface, appropriately reduce the viscosity of the coating to make it easier to penetrate into the pores of the concrete; for large-area construction, adjust the spraying pressure and nozzle distance to ensure uniform coating coverage.

[0073] Example 1

[0074] A universal epoxy sealant coating for concrete surfaces, comprising components A and B in a weight ratio of 3:1. Component A, measured by weight, comprises: 50 parts bisphenol A epoxy resin, 10 parts vinyl cyclohexene diepoxide, 15 parts titanium dioxide, 15 parts talc, 10 parts precipitated barium sulfate, 1 part organosilicon defoamer, 2 parts polyacrylate dispersant, 1 part organosilicon leveling agent, and 2 parts bentonite.

[0075] Component B comprises, by weight, 40 parts of an aliphatic polyamine curing agent, 3 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 2 parts of γ-aminopropyltriethoxysilane.

[0076] Preparation method:

[0077] Preparation of component A

[0078] Add bisphenol A epoxy resin and vinyl cyclohexene diepoxide into a stirring kettle and stir at a speed of 400 r / min for 8 minutes.

[0079] Add silicone defoamer, polyacrylate dispersant, titanium dioxide, talc, precipitated barium sulfate and bentonite in sequence, increase the stirring speed to 1000 r / min, stir for 20 minutes, and grind with a sand mill to a fineness of less than 30 μm.

[0080] The ground slurry was transferred to a paint mixing kettle, an organosilicon leveling agent was added, and the mixture was stirred at a speed of 600 r / min for 12 minutes to obtain component A.

[0081] Preparation of component B

[0082] Add aliphatic polyamine curing agent into the stirring kettle and stir at a speed of 300r / min.

[0083] 2,4,6-tris(dimethylaminomethyl)phenol and γ-aminopropyltriethoxysilane were added in sequence, and stirring was continued for 12 minutes to obtain component B.

[0084] Coating application

[0085] Mix component A and component B in a weight ratio of 3:1 and stir for 8 minutes.

[0086] Pre-treat the concrete surface and use sandblasting to remove surface impurities.

[0087] The mixed paint is evenly applied on the concrete surface by spraying, and the coating thickness is controlled at 0.3mm.

[0088] Curing was carried out at room temperature (25°C) for 16 hours.

[0089] Example 2

[0090] A universal epoxy sealant coating for concrete surfaces, comprising components A and B in a weight ratio of 2.5:1. Component A, by weight, comprises: 45 parts bisphenol F epoxy resin, 12 parts benzyl glycidyl ether, 12 parts titanium dioxide, 18 parts talc, 10 parts precipitated barium sulfate, 1.5 parts polyether defoamer, 2.5 parts polyacrylate dispersant, 1.5 parts fluorocarbon leveling agent, and 2.5 parts fumed silica.

[0091] Component B comprises, by weight, 45 parts of alicyclic polyamine curing agent, 4 parts of N,N-dimethylbenzylamine, and 2.5 parts of γ-glycidyloxypropyltrimethoxysilane.

[0092] Preparation method:

[0093] Preparation of component A

[0094] Add bisphenol F epoxy resin and benzyl glycidyl ether into a stirring kettle and stir at a speed of 350 r / min for 7 minutes.

[0095] Polyether defoamer, polyacrylate dispersant, titanium dioxide, talc, precipitated barium sulfate, and fumed silica were added in sequence, the stirring speed was increased to 900 r / min, and after stirring for 25 minutes, the mixture was ground with a sand mill to a fineness of less than 30 μm.

[0096] The ground slurry was transferred to a paint mixing kettle, a fluorocarbon leveling agent was added, and the mixture was stirred at a speed of 700 r / min for 13 minutes to obtain component A.

[0097] Preparation of component B

[0098] Add alicyclic polyamine curing agent into the stirring kettle and stir at a speed of 250r / min.

[0099] N,N-dimethylbenzylamine and γ-glycidyloxypropyltrimethoxysilane were added in sequence, and stirring was continued for 13 minutes to obtain component B.

[0100] Coating application

[0101] Mix component A and component B in a weight ratio of 2.5:1 and stir for 7 minutes.

[0102] Grind and clean the concrete surface.

[0103] The mixed paint is evenly applied on the concrete surface by brushing, and the coating thickness is controlled at 0.2mm.

[0104] Curing at room temperature (23 ° C) for 24 hours.

[0105] Example 3

[0106] A universal epoxy sealant coating for concrete surfaces, comprising components A and B in a weight ratio of 3.5:1. Component A, by weight, comprises: 55 parts of phenolic epoxy resin, 8 parts of propylene glycol diglycidyl ether, 18 parts of titanium dioxide, 12 parts of talc, 8 parts of precipitated barium sulfate, 1.5 parts of a mixture of an organosilicon defoamer and a polyether defoamer (1:1 by weight), 2 parts of a polyacrylate dispersant, 1.5 parts of an organosilicon leveling agent, and 2 parts of hydrogenated castor oil.

[0107] Component B comprises, by weight, 42 parts of polyamide curing agent, 3.5 parts of DMP-30, and 2 parts of γ-aminopropyltriethoxysilane.

[0108] Preparation method:

[0109] Preparation of component A

[0110] Add phenolic epoxy resin and propylene glycol diglycidyl ether into a stirring kettle and stir at a speed of 450 r / min for 9 minutes.

[0111] Add the compound of silicone defoamer and polyether defoamer, polyacrylate dispersant, titanium dioxide, talc, precipitated barium sulfate and hydrogenated castor oil in sequence, increase the stirring speed to 1100 r / min, stir for 18 minutes, and then grind with a sand mill to a fineness of less than 30 μm.

[0112] The ground slurry was transferred to a paint mixing kettle, an organosilicon leveling agent was added, and the mixture was stirred at a speed of 650 r / min for 14 min to obtain component A.

[0113] Preparation of component B

[0114] Add polyamide curing agent into the stirring kettle and stir at a speed of 350r / min.

[0115] DMP-30 and γ-aminopropyltriethoxysilane were added in sequence, and stirring was continued for 14 minutes to obtain component B.

[0116] Coating application

[0117] Mix component A and component B in a weight ratio of 3.5:1 and stir for 9 minutes.

[0118] Rinse the concrete surface with a high-pressure water gun and then let it dry.

[0119] The mixed paint is evenly applied to the concrete surface by roller coating, and the coating thickness is controlled at 0.4mm.

[0120] Curing was carried out at room temperature (28°C) for 16 hours.

[0121] Example 4

[0122] A universal epoxy sealant coating for concrete surfaces, with components A and B in a weight ratio of 3:1. Component A, by weight, comprises: 50 parts bisphenol F epoxy resin, 10 parts reactive diluent (propylene glycol diglycidyl ether), 25 parts talc and 15 parts nano-titanium dioxide, 2 parts hydrogenated castor oil, 2 parts polyacrylate dispersant, 1.5 parts silicone leveling agent, and 2 parts hydrogenated castor oil. The coating also contains 5 parts corrosion inhibitor microcapsules (core material: molybdate corrosion inhibitor, wall material: pH-sensitive polymer (polymethyl methacrylate)), 3 parts penetration enhancer microcapsules (core material: alkylphenol polyoxyethylene ether, wall material: pressure-responsive polymer (polyurethane)), 2 parts polymer dispersant, and 1 part polyether defoamer.

[0123] Component B comprises, by weight, 70 parts of alicyclic polyamine curing agent, 3 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 2 parts of γ-aminopropyltriethoxysilane.

[0124] Preparation method:

[0125] Preparation of component A

[0126] Add epoxy resin and active diluent to the stirring kettle and stir at 400 r / min for 8 minutes. Grinding and dispersion stage: add talc powder, nano titanium dioxide, anti-settling agent, dispersant, and defoamer in sequence, stir at 1200 r / min for 20 minutes, and grind to a fineness of 25 μm using a sand mill.

[0127] The corrosion inhibitor microcapsules and the penetration enhancer microcapsules were slowly added to the ground slurry and stirred at a low speed of 600 r / min for 15 min (to avoid destroying the microcapsule structure).

[0128] Preparation of component B

[0129] Add alicyclic polyamine curing agent into the stirring kettle and stir at a speed of 350 r / min.

[0130] 3 parts of 2,4,6-tris(dimethylaminomethyl)phenol and γ-aminopropyltriethoxysilane were added in sequence, and stirring was continued for 20 minutes to obtain component B.

[0131] Coating application

[0132] Mix component A and component B in a weight ratio of 3:1 and stir for 9 minutes.

[0133] Rinse the concrete surface with a high-pressure water gun and then let it dry.

[0134] The mixed paint is evenly applied on the concrete surface by roller coating, and the coating thickness is controlled at 0.2mm.

[0135] Curing was carried out at room temperature (28°C) for 16 hours.

[0136] The above microcapsule preparation process

[0137] Corrosion inhibitor microcapsules (pH responsive)

[0138] Preparation method: Core material dissolution: dissolve 10 g of molybdate corrosion inhibitor in an ethanol-water mixture (volume ratio 3:1) to form a core material solution.

[0139] Wall material emulsification: 20 g of polymethyl methacrylate was dissolved in acetone, added to the core material solution, and ultrasonic emulsification was performed for 30 min (frequency 40 kHz) to form an oil-in-water emulsion.

[0140] Curing and cross-linking: Ammonia water (pH=9) was added dropwise to the emulsion, and the acetone was volatilized under stirring, and the wall material polymethyl methacrylate was cross-linked and cured. The microcapsules with a particle size of 5-10 μm were obtained by filtration and drying.

[0141] Response mechanism: When the environmental pH is less than 6 (acidic corrosion) or the Cl- concentration is greater than 0.5% (marine environment), the polymer chain segments of the wall material dissociate and release the corrosion inhibitor.

[0142] Comparative Example 1

[0143] A common epoxy sealant coating with a weight ratio of components A and B of 3:1.

[0144] Component A, calculated by weight, includes: 50 parts of ordinary bisphenol A epoxy resin, 10 parts of ordinary diluent, 15 parts of titanium dioxide, 15 parts of calcium carbonate, 1 part of ordinary defoaming agent, 2 parts of ordinary dispersant, 1 part of ordinary leveling agent, and 2 parts of ordinary anti-settling agent.

[0145] Component B includes, by weight: 40 parts of common curing agent and 3 parts of common accelerator.

[0146] Preparation method:

[0147] Preparation of component A

[0148] Add ordinary bisphenol A epoxy resin and ordinary diluent into a stirring kettle and stir at a speed of 400 r / min for 8 minutes.

[0149] Ordinary defoaming agent, ordinary dispersant, titanium dioxide, calcium carbonate and ordinary anti-settling agent were added in sequence, the stirring speed was increased to 1000r / min, and after stirring for 20 minutes, it was simply filtered without strict grinding.

[0150] The slurry was transferred to a paint mixing kettle, a common leveling agent was added, and the mixture was stirred at a speed of 600 r / min for 12 minutes to obtain component A.

[0151] Preparation of component B

[0152] Add common curing agent into the stirring kettle and stir at a speed of 300r / min.

[0153] Add a common accelerator and continue stirring for 12 minutes to obtain component B.

[0154] Coating application

[0155] Mix component A and component B in a weight ratio of 3:1 and stir for 8 minutes.

[0156] Construction can be carried out after simply cleaning the concrete surface.

[0157] The mixed paint is applied to the concrete surface by spraying, and the coating thickness is controlled at 0.3mm.

[0158] Curing was carried out at room temperature (25°C) for 36 hours.

[0159] Comparative Example 2

[0160] A common epoxy sealant coating with a weight ratio of components A to B of 3.5:1.

[0161] Component A, calculated by weight, includes: 50-70 parts of ordinary bisphenol A epoxy resin, 5 parts of ordinary diluent, 15 parts of titanium dioxide, 10 parts of calcium carbonate, 1 part of ordinary defoaming agent, 2 parts of ordinary dispersant, 1 part of ordinary leveling agent, and 2 parts of ordinary anti-settling agent.

[0162] Component B comprises, by weight, 40 to 60 parts of a common curing agent, 3 to 5 parts of a common accelerator, and 10 to 15 parts of a diluent.

[0163] Preparation method:

[0164] Preparation of component A

[0165] Add ordinary bisphenol A epoxy resin and ordinary diluent into a stirring kettle and stir at a speed of 400 r / min for 8 minutes.

[0166] Defoaming agent, common dispersant, titanium dioxide, calcium carbonate and common anti-settling agent were added in sequence, the stirring speed was increased to 1000r / min, and after stirring for 20 minutes, it was simply filtered without strict grinding.

[0167] The slurry was transferred to a paint mixing kettle, a common leveling agent was added, and the mixture was stirred at a speed of 600 r / min for 15 minutes to obtain component A.

[0168] Preparation of component B

[0169] Add common curing agent into the stirring kettle and stir at a speed of 300r / min.

[0170] Add common accelerator and diluent, continue stirring for 20 minutes to obtain component B.

[0171] Coating application

[0172] Mix component A and component B in a weight ratio of 3.5:1 and stir for 10 minutes.

[0173] Construction can be carried out after simply cleaning the concrete surface.

[0174] The mixed paint is applied to the concrete surface by spraying, and the coating thickness is controlled at 0.3mm.

[0175] Curing was carried out at room temperature (25°C) for 36 hours.

[0176]

[0177] Table 1

[0178] Table 1 is a comparison table of the detection of each embodiment and comparative example.

[0179] Application Scenario

[0180] Marine Engineering: The coating of this invention is suitable for various concrete structures in marine environments, such as ports, cross-sea bridges, and offshore drilling platforms. In these structures, the concrete is subject to long-term erosion by seawater and penetration by chloride ions. The coating of this invention can effectively resist these erosions and extend the service life of the concrete structure.

[0181] Industrial buildings: In industrial fields such as chemical and metallurgy, concrete structures are often exposed to various chemicals such as acids, alkalis, and salts. The coating of this invention has excellent chemical corrosion resistance and can protect concrete structures from the erosion of these chemicals, ensuring the safe and stable operation of industrial buildings.

[0182] Cold Region Buildings: In cold northern regions, concrete structures face the test of freeze-thaw cycles. The coating of this invention has good flexibility and frost resistance, can withstand the freeze-thaw cycles of concrete, prevent coating shedding and concrete cracking, and improve the durability of the building.

[0183] Municipal Engineering: Concrete structures in urban bridges, tunnels, sewage treatment plants, and other municipal engineering projects also require good protection. The coating of the present invention can provide effective protection for these municipal engineering projects, extending their service life and reducing maintenance costs.

[0184] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0185] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0186] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present disclosure and are not intended to limit the scope of the present disclosure. Other changes or modifications may be made based on the above disclosure, and such changes or modifications are still within the scope of the present disclosure.

Claims

1. A universal epoxy sealing coating for concrete surface, characterized in that: The coating comprises component A and component B, wherein the weight ratio of component A to component B is (2-4):1, the component A comprises epoxy resin, reactive diluent, pigment, filler, defoamer, dispersant, leveling agent and anti-settling agent, and the component B comprises curing agent, accelerator and coupling agent.

2. A universal epoxy sealing coating for concrete surface according to claim 1, characterized in that: Component A, calculated by weight, comprises: 40-60 parts of epoxy resin; 5-15 parts of active diluent; 30-50 parts of pigment and filler; 0.5-2 parts of defoaming agent; 1-3 parts of dispersant; 0.5-2 parts of leveling agent; and 1-3 parts of anti-settling agent.

3. The universal epoxy sealing coating for concrete surface according to claim 2, characterized in that: Component B comprises, by weight, 50 to 90 parts of curing agent, 1 to 5 parts of accelerator, 1 to 3 parts of coupling agent, and 5 to 10 parts of diluent.

4. The universal epoxy sealing coating for concrete surface according to claim 3, characterized in that: The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin or novolac epoxy resin.

5. The universal epoxy sealing coating for concrete surface according to claim 4, characterized in that: The active diluent is one or more of vinyl cyclohexene diepoxide, benzyl glycidyl ether or propylene glycol diglycidyl ether.

6. The universal epoxy sealing coating for concrete surface according to claim 5, characterized in that: The leveling agent is any one of an organic silicon leveling agent or a fluorocarbon leveling agent.

7. The universal epoxy sealing coating for concrete surface according to claim 6, characterized in that: The anti-settling agent is one or more of bentonite, fumed silica or hydrogenated castor oil.

8. The universal epoxy sealing coating for concrete surface according to claim 7, characterized in that: The curing agent is one or more of an aliphatic polyamine curing agent, an alicyclic polyamine curing agent or a polyamide curing agent.

9. The universal epoxy sealing coating for concrete surface according to claim 8, characterized in that: The accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, N,N-dimethylbenzylamine or DMP-30.

10. The universal epoxy sealing coating for concrete surface according to claim 9, characterized in that: The coupling agent is a silane coupling agent.

11. The universal epoxy sealing coating for concrete surface according to claim 10, characterized in that: Before construction, mix component A and component B according to the specified weight ratio and stir evenly for 5 to 10 minutes. After the coating is completed, cure it at 20-30°C for 24 to 48 hours.

12. A method for preparing a universal epoxy sealing coating on a concrete surface, comprising preparing the coating according to any one of claims 1 to 11, wherein: The following steps are involved: Preparation of component A Pre-dispersion stage: Add epoxy resin and active diluent into the stirring kettle, start stirring, control the stirring speed at 300-500r / min, and stir for 5-10 minutes; Grinding and dispersing stage: add defoamer, dispersant, pigment, filler, and anti-settling agent in sequence, continue stirring, increase the stirring speed to 800-1200r / min, stir for 15-30min, and then grind with a sand mill to control the grinding fineness to below 30μm; Paint mixing stage: transfer the ground slurry to the paint mixing kettle, add leveling agent, adjust the stirring speed to 500-800r / min, and stir for 10-15 minutes to mix all the ingredients evenly to obtain component A; Preparation of component B Add curing agent into the stirring tank, start stirring, and control the stirring speed at 200-400r / min; Add the accelerator, coupling agent and diluent in sequence and continue stirring for 10 to 15 minutes to obtain component B.

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