Multi-element modified polyurethane weather-resistant waterproof coating, preparation method and application thereof

Abstract

This invention relates to the field of coating technology, specifically to a multi-component modified polyurethane weather-resistant and waterproof coating, its preparation method, and its application. The invention involves mixing polyaspartic acid ester resin, hydrogenated epoxy resin, and a silane coupling agent, followed by graft modification to obtain a modified polyaspartic acid ester resin. The hydrogenated epoxy resin accounts for 10-30% of the mass of the polyaspartic acid ester resin; the mass ratio of the hydrogenated epoxy resin to the silane coupling agent is 3.5-4.5:1. By grafting hydrogenated epoxy resin and a silane coupling agent onto the polyaspartic acid ester resin and controlling their amounts, this invention significantly improves the water resistance of the coating, enabling it to be used in areas with fluctuating water levels in hydraulic structures, as well as in scenarios involving long-term immersion in water. It also significantly enhances the interlayer adhesion between the coating and the inorganic interface, resulting in high bonding strength.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a multi-component modified polyurethane weather-resistant and waterproof coating, its preparation method, and its application. Background Technology

[0002] Polyaspartic acid ester resin is a special type of sterically hindered secondary amine compound. Its steric hindrance and inductive effect reduce the reactivity of the secondary amine in the reaction with -NCO, resulting in longer application time and higher film adhesion compared to traditional polyurea materials. Polyaspartic acid ester resin combined with an aliphatic isocyanate curing agent produces polyaspartic acid ester resin polyurea (PAE polyurea) coatings with excellent mechanical properties and aging resistance. Compared to general hydroxyl resins and epoxy resins, it exhibits superior drying speed. This material provides long-lasting corrosion protection and gloss / color retention, with abrasion loss ≤20mg. The application environment humidity must be below 85%, and the surface temperature must be 3°C above the dew point. The curing speed is 8 times faster than traditional coatings, but it is not suitable for continuous immersion in water.

[0003] A related technology discloses a method for preparing siloxane-modified aspartic acid ester. Polyethylene polyamine and butenedioic acid diester react to obtain aspartic acid ester polyamine, and then a silane coupling agent capable of reacting with secondary amines is added to obtain the siloxane-modified aspartic acid ester. The silane coupling agent is selected from those containing epoxy and / or NCO groups, and the molar ratio of the added silane coupling agent to the added polyethylene polyamine is (1~n):1, where n is the number of repeating units in the aspartic acid ester. However, this related technology uses a relatively high amount of silane coupling agent to obtain high adhesive strength, which leads to a higher hydroxyl content in the modified resin. The reaction between hydroxyl groups and isocyanate curing agents is significantly slower than that with amino groups. When applied to hydraulic structures, this results in poor initial water resistance and difficulty in adapting to long-term immersion environments.

[0004] A related technology discloses a method for preparing low-viscosity polyaspartic acid ester resin, comprising the steps of: crosslinking the amino groups in the polyaspartic acid ester with the epoxy groups of neopentyl glycol diglycidyl ether to obtain a preliminarily modified polyaspartic acid ester; mixing the preliminarily modified polyaspartic acid ester with nano-silica and a silane coupling agent to obtain a low-viscosity polyaspartic acid ester resin. This related technology, through the combination of chemical crosslinking and nanocomposite technology, significantly optimizes the viscosity, mechanical properties, and processing efficiency of polyaspartic acid ester resin while maintaining its environmental advantages, aligning with the development trend of high solids, low viscosity, and high performance in the coating industry, and possessing high application potential. However, its low-viscosity polyaspartic acid ester resin has poor water resistance, making it difficult to withstand long-term immersion in water when applied in hydraulic structures. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a multi-component modified polyurethane weather-resistant and waterproof coating, its preparation method, and its application. The modified polyaspartic acid ester resin prepared by this invention exhibits excellent water resistance and adhesion, and can be used in environments with long-term immersion in water.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing modified polyaspartic acid ester resin, comprising the following steps: Polyaspartic acid ester resin, hydrogenated epoxy resin and silane coupling agent are mixed and grafted under a protective atmosphere to obtain modified polyaspartic acid ester resin. The grafting modification is performed at a temperature of 60-90℃ for 2-4 hours. The silane coupling agent includes one or more of KH560, KH561, KH550, KH-792, KH-602 and KH570; The hydrogenated epoxy resin accounts for 10-30% of the mass of the polyaspartic acid ester resin; The mass ratio of the hydrogenated epoxy resin to the silane coupling agent can be 3.5~4.5:1.

[0007] The present invention also provides a modified polyaspartic acid ester resin prepared by the preparation method described in the above technical solution.

[0008] This invention provides a method for preparing modified polyurethane resin, comprising the following steps: mixing polyurethane prepolymer resin and modifier, and performing graft modification to obtain modified polyurethane resin; The modifier includes acrylic resin, fluorocarbon resin, or hydroxyl-terminated polydimethylsiloxane.

[0009] Preferably, the acrylic resin accounts for 10-30% of the mass of the polyurethane prepolymer resin; The fluorocarbon resin accounts for 5-20% of the mass of the polyurethane prepolymer resin; The hydroxyl-terminated polydimethylsiloxane accounts for 10-20% of the mass of the polyurethane prepolymer resin; The grafting modification temperature is 75~85℃, and the time is 1~5h.

[0010] Preferably, when the modifier is an acrylic resin, the modified polyurethane resin is an acrylic-modified polyurethane resin; When the modifier is a fluorocarbon resin, the modified polyurethane resin is a fluorocarbon modified polyurethane resin. When the modifier is hydroxyl-terminated polydimethylsiloxane, the modified polyurethane resin is a polydimethylsiloxane-modified polyurethane resin.

[0011] The present invention also provides the application of the modified polyaspartic acid ester resin or the modified polyurethane resin described in the above technical solutions in coatings.

[0012] This invention provides a multi-component modified polyurethane weather-resistant and waterproof coating, comprising separately packaged component A and component B; Component A includes polyaspartic acid ester resin, the modified polyaspartic acid ester resin described in the above technical solution, and polyetheramine; Component B includes a first polyurethane prepolymer resin and the modified polyurethane resin described in the above technical solution. The modified polyurethane resin includes acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. When the multi-component modified polyurethane weather-resistant waterproof coating is used, the mass ratio of component A to component B is 1:1.1~1.7, and the molar amount of NCO groups in component B to the total molar amount of hydroxyl and amino groups in component A is 1.05~1.25:1.

[0013] Preferably, in component B, the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and the first polyurethane prepolymer resin is 1:6~10, the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and acrylic acid-modified polyurethane resin is 1:3~5, and the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and fluorocarbon-modified polyurethane resin is 1:6~8. The mass ratio of polyaspartic acid ester resin to modified polyaspartic acid ester resin in component A is 3~6:4~7; The mass of the polyetheramine accounts for 25-40% of the total mass of the NCO functional groups in component B.

[0014] Preferably, component A further includes excipients, which include one or more of pigments, fillers, dispersants, defoamers, and thixotropic agents.

[0015] This invention also provides a method for preparing the multi-component modified polyurethane weather-resistant and waterproof coating described in the above technical solution, comprising the following steps: The first polyaspartic ester resin, the modified polyaspartic ester resin, and the polyetheramine were mixed to obtain component A; Component B is obtained by mixing polyurethane prepolymer resin, acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. The components A and B are packaged separately to obtain a multi-component modified polyurethane weather-resistant waterproof coating.

[0016] The present invention also provides the application of the multi-component modified polyurethane weather-resistant and waterproof coating described in the above technical solution or the multi-component modified polyurethane weather-resistant and waterproof coating prepared by the preparation method described in the above technical solution in the protection of hydraulic structures, highways or bridges. The application areas include areas with fluctuating water levels, areas that have been submerged for a long time, coastal areas with strong sunlight, and northern freeze-thaw zones.

[0017] Whether epoxy resin is directly added to coatings for blending or grafted onto polyurethane prepolymers, it results in slow curing of the epoxy groups and non-primary amine curing agents at room temperature, leading to poor initial water resistance. This invention grafts hydrogenated epoxy resin onto polyaspartic acid ester resin (a secondary amine resin), which has relatively poor reactivity but good weather resistance and low-temperature deformation properties, utilizing the ring-opening reaction of epoxy and secondary amine groups to synthesize modified polyaspartic acid ester resin. Furthermore, the use of hydrogenated epoxy resin eliminates the risk of yellowing due to double bonds, significantly improving the weather resistance and water resistance of polyurethane coatings. Epoxy resin exhibits poor adhesion at low surface energy interfaces; this invention modifies it by adding a silane coupling agent, utilizing the claw-like structure of this substance to improve interlayer adhesion.

[0018] This invention significantly improves the long-term water resistance and adhesion of polyaspartic acid ester resin by strictly controlling the dosage and ratio of hydrogenated epoxy resin and silane coupling agent. If the dosage of both hydrogenated epoxy resin and silane coupling agent is too high, the content of hydroxyl groups generated after grafting will be too high. Compared with secondary amine groups, the generated urethane groups cure more slowly at room temperature than urea groups, resulting in poor water resistance in the initial curing stage (within 14 days after application). Conversely, if the dosage of both modifiers is too low, the modification effect (referring to the long-term water resistance and adhesion of the coating) will not meet the expected requirements.

[0019] Compared to simple blending and single modification using silane coupling agents or hydrogenated epoxy resins, this invention employs synergistic graft modification with hydrogenated epoxy resin and silane coupling agents. By precisely controlling the ratio of the two modifiers, hydrogenated epoxy resin improves the long-term water resistance of the coating, while silane coupling agents improve the adhesion between the coating and the substrate or intermediate coat. Under the premise of a constant total epoxy group content, excessive silane coupling agent dosage will lead to color floating and mottled appearance of the coating, and the water resistance will also decrease. Conversely, insufficient dosage will not effectively improve the adhesion performance of the coating. Furthermore, the amount of added silane coupling agent can balance water resistance and adhesion. By adding hydrogenated epoxy resin for synergistic modification, the decrease in water resistance caused by the silane coupling agent is compensated, and the water resistance of polyaspartic acid ester resin is improved. The obtained modified polyaspartic acid ester resin, as one of the raw materials for multi-element modified polyurethane coatings, can give the coating good long-term water resistance and adhesion. Moreover, the hydrogenated epoxy resin does not contain double bond structures such as benzene rings, thus eliminating the shortcomings of poor weather resistance and easy yellowing of ordinary epoxy resins in terms of structure.

[0020] This invention modifies polyurethane prepolymer resin by grafting acrylic resin onto it, allowing the hydroxyl groups of the acrylic resin to react with the isocyanate groups of the polyurethane prepolymer resin. Grafting acrylic resin enables the coating to be used on traditional concrete substrates as well as on polar plastics and composite materials such as carbon fiber and glass fiber, achieving adhesion to various substrates. Simultaneously, it improves the coating's heat resistance, enabling it to withstand hot water and humid conditions.

[0021] This invention modifies polyurethane prepolymer resin by grafting fluorocarbon resin, which allows for spray application with high efficiency. Furthermore, the raw materials used in the preparation of this invention avoid the use of perfluoropolyether alcohol, resulting in low cost, while ensuring high toughness of the coating.

[0022] The surfaces of hydraulic structures often harbor silt, barnacles, algae, shellfish, and other microorganisms, as well as various types of debris, reducing their flow capacity. This invention, by adding fluorocarbon-modified polyurethane resin, improves the smoothness of the coating surface and provides a certain degree of self-cleaning function. Furthermore, by adding polydimethylsiloxane (PDMS)-modified polyurethane resin, which has stronger hydrophobicity, this invention increases the contact angle between the coating surface and water, and also enhances the coating's thermal stability and leveling properties.

[0023] This invention provides a multi-component modified polyurethane weather-resistant and waterproof coating, comprising independently packaged components A and B. Component A includes polyaspartic acid ester resin, modified polyaspartic acid ester resin, and polyetheramine. Component B includes a first polyurethane prepolymer resin, acrylic-modified polyurethane resin, fluorocarbon-modified polyurethane resin, and polydimethylsiloxane-modified polyurethane resin. This invention significantly improves the water resistance of the coating by grafting hydrogenated epoxy resin onto the polyaspartic acid ester resin, enabling it to be used both above and below the water level fluctuation zone of hydraulic structures, i.e., for long-term immersion in water. Furthermore, by grafting a silane coupling agent onto the polyaspartic acid ester resin, it significantly improves the interlayer adhesion between the coating and the inorganic interface, resulting in high bonding strength. The addition of acrylic-modified polyurethane resin allows the coating to be used on traditional concrete substrates as well as on polar plastics and composite materials such as carbon fiber and glass fiber, achieving bonding to various substrates. Simultaneously, it significantly improves the heat resistance of the coating, enabling it to withstand hot water and humid conditions. This invention significantly improves the weather resistance, color retention, and freeze-thaw resistance of coatings by adding fluorocarbon-modified polyurethane resin, enabling its application in areas with strong sunlight, such as coastal regions, and in frigid northern areas. It also reduces costs compared to perfluoropolyether alcohol, facilitating widespread adoption. Furthermore, by adding polydimethylsiloxane-modified polyurethane resin, this invention significantly improves the hydrophobicity of coatings, reducing the adhesion of debris from water flow to the coating surface and extending its service life. The multi-element modified polyurethane coating provided by this invention possesses excellent water resistance, corrosion resistance, roughness reduction, stain resistance, weather resistance, freeze damage resistance (anti-ice adhesion), damp heat resistance, and high toughness. Its superior overall performance effectively solves the problem of existing coatings having limited functionality or being unsuitable for the protection of hydraulic structures.

[0024] The multi-component modified polyurethane weather-resistant and waterproof coating provided by this invention uses a variety of synthetic grafted modified resins and strictly and precisely controls the mass ratio of each component to synergistically modify the polyurethane coating, resulting in a homogeneous sprayable coating with comprehensive performance superior to single-modified or simply blended polyurethane coatings. Attached Figure Description

[0025] Figure 1 The image shows the two-component unmodified polyurethane coating prepared for Comparative Example 19 after one year of use. Detailed Implementation

[0026] This invention provides a method for preparing modified polyaspartic ester resin, comprising the following steps: mixing polyaspartic ester resin (referred to as first polyaspartic ester resin), hydrogenated epoxy resin and silane coupling agent, and performing graft modification (referred to as first graft modification) under a protective atmosphere to obtain modified polyaspartic ester resin.

[0027] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0028] In this invention, the secondary amino equivalent of the first polyaspartic ester resin can be 277~299, or 280~295, or even 285; the first polyaspartic ester resin may include F420 resin (Shenzhen Feiyang) and / or NH1420 resin (Bayer, now Covestro).

[0029] In this invention, the hydrogenated epoxy resin can be a hydrogenated bisphenol A epoxy resin, and the epoxy equivalent can be 215~230, or even 220~255. In this invention, the hydrogenated epoxy resin includes EP4080-E resin (Adico), EPALLOY 5000 resin (Hunsmay), and HE-2025 resin (Complexed High-Tech Materials), etc. In this invention, the silane coupling agent includes γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), γ-glycidoxypropyltriethoxysilane (KH561), γ-aminopropyltriethoxysilane (KH550), N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (KH-792), N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane (KH-602), and γ-(methacryloyloxy)propyltrimethoxysilane (KH570), specifically KH560. In this invention, the mass ratio of the hydrogenated epoxy resin to the silane coupling agent is 3.5~4.5:1, and can also be 3.8~4.2:1, specifically 4:1.

[0030] In this invention, the mass content of the hydrogenated epoxy resin accounts for 10-30% of the mass of the first polyaspartic ester resin, and can also be 15-25%, and can be further 20%.

[0031] In this invention, the temperature of the first grafting modification is 60-90°C, which can also be 75-85°C, further 78-82°C, and specifically 80°C; the time of the first grafting modification is 2-4 hours, which can also be 2.5-3.5 hours, and further 3 hours; the first grafting modification is carried out under a protective atmosphere, which may include nitrogen, argon, or helium. This invention utilizes the ring-opening reaction of epoxy groups and secondary amine groups to synthesize modified polyaspartic acid ester resin.

[0032] This invention employs hydrogenated epoxy resin and silane coupling agent to synergistically graft and modify polyaspartic acid ester resin. The hydrogenated epoxy resin improves water resistance and eliminates the risk of yellowing, while the silane coupling agent improves adhesion. By controlling the ratio of the two, a balance between water resistance and adhesion is achieved, resulting in a modified polyaspartic acid ester resin that combines both water resistance and adhesion.

[0033] The present invention also provides a modified polyaspartic acid ester resin prepared by the preparation method described in the above technical solution.

[0034] This invention significantly improves the water resistance and adhesion of polyaspartic acid ester resin by controlling the ratio of hydrogenated epoxy resin and silane coupling agent. As one of the raw materials of component A of the coating, it exhibits good water resistance and adhesion after curing.

[0035] This invention significantly improves the long-term water resistance and adhesion of polyaspartic acid ester resin by strictly controlling the dosage and ratio of hydrogenated epoxy resin and silane coupling agent. If the dosage of both hydrogenated epoxy resin and silane coupling agent is too high, the content of hydroxyl groups generated after grafting will be too high. Compared with secondary amine groups, the generated urethane groups cure more slowly at room temperature than urea groups, resulting in poor water resistance in the initial curing stage (within 14 days after application). Conversely, if the dosage of both modifiers is too low, the modification effect (referring to the long-term water resistance and adhesion of the coating) will not meet the expected requirements.

[0036] Whether epoxy resin is directly added to coatings for blending or grafted onto polyurethane prepolymers, it results in slow curing of the epoxy groups and non-primary amine curing agents at room temperature, leading to poor initial water resistance. This invention grafts hydrogenated epoxy resin onto polyaspartic acid ester resin (a secondary amine resin), which has relatively poor reactivity but good weather resistance and low-temperature deformation properties, utilizing the ring-opening reaction of epoxy and secondary amine groups to synthesize modified polyaspartic acid ester resin. Furthermore, the use of hydrogenated epoxy resin eliminates the risk of yellowing due to double bonds, significantly improving the weather resistance and water resistance of polyurethane coatings. Epoxy resin exhibits poor adhesion at low surface energy interfaces; this invention modifies it by adding a silane coupling agent, utilizing the claw-like structure of this substance to improve interlayer adhesion.

[0037] This invention controls the ratio of hydrogenated epoxy resin and silane coupling agent as modifiers. Hydrogenated epoxy resin improves the long-term water resistance of the coating, while the silane coupling agent improves the adhesion between the coating and the substrate or intermediate coat. With a constant total epoxy group content, excessive silane coupling agent dosage leads to color floating and mottled appearance of the coating, and also reduces water resistance; conversely, insufficient dosage fails to effectively improve the coating's adhesion. This invention, after determining the amount of silane coupling agent, uses hydrogenated epoxy resin to provide the remaining epoxy groups, compensating for the decrease in water resistance caused by the silane coupling agent. This invention compensates for the decrease in water resistance caused by the silane coupling agent through synergistic modification with the addition of hydrogenated epoxy resin.

[0038] This invention modifies aspartic acid ester by mixing hydrogenated epoxy resin and an epoxy-containing silane coupling agent, and carries out the modification reaction at a high temperature of 60~90℃. This can enhance the reactivity of the secondary amine group, enabling it to react rapidly and completely with the epoxy group. The hydrogenated epoxy resin and silane coupling agent are effectively grafted onto the polyaspartic acid ester resin, overcoming the shortcomings of low reaction efficiency and inability to achieve the modification purpose when blending at room temperature.

[0039] This invention significantly improves the water resistance of coatings by grafting hydrogenated epoxy resin and silane coupling agent onto polyaspartic ester resin and controlling the amount of both. This allows the coating to be used in areas above the water level fluctuation zone of hydraulic structures, as well as in scenarios where the coating is immersed in water for a long time. It also significantly improves the interlayer adhesion between the coating and the inorganic interface, resulting in high bonding strength.

[0040] The present invention also provides a method for preparing a modified polyurethane resin, wherein a polyurethane prepolymer resin (referred to as the first polyurethane prepolymer resin) and a modifier are mixed and grafted (referred to as the second grafting modification) to obtain a modified polyurethane resin; wherein the modifier includes acrylic resin, fluorocarbon resin or hydroxyl-terminated polydimethylsiloxane.

[0041] In this invention, the acrylic resin can be one or more of WF-B012 resin (Wanbo New Materials), WF-H6018 resin (Wanbo New Materials), and WF-H0821 resin (Wanbo New Materials), or it can be a mixture of WF-B012 resin and at least one of WF-H6018 resin and WF-H0821 resin. The mass content of WF-B012 resin in the mixed acrylic resin is ≥50%, and can also be 50-90%, specifically 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. In this invention, the mass of the acrylic resin can account for 10-30% of the mass of the first polyurethane prepolymer resin, and can also be 15-25%, and can further be 20%.

[0042] In this invention, the fluorocarbon resin includes WF-Q212 resin (Wanbo New Materials). In this invention, the mass of the fluorocarbon resin can be 5-20% of the mass of the first polyurethane prepolymer resin, and can also be 10-15%.

[0043] In this invention, the mass of the hydroxyl-terminated polydimethylsiloxane can be 10-20% of the mass of the first polyurethane prepolymer resin, or 12-18%, or even 15%. In this invention, the number average molecular weight of the hydroxyl-terminated polydimethylsiloxane (PDMS) can be 300-2500, 300-2000, or 500-1000. A large molecular weight is not recommended, otherwise the viscosity will be high, exhibiting silicone rubber properties, resulting in poor compatibility with polyurethane during modification and synthesis, and easily leading to phase separation. The PDMS can include PDMS500 (Jipeng Silicon Fluorine Material) and / or PDMS1000 (Jipeng Silicon Fluorine Material), or a mixture of PDMS500 and PDMS1000. The mass content of PDMS500 in the mixture of PDMS500 and PDMS1000 is ≥30%, and can be 30-90%, or further 40-80%, specifically 30%, 40%, 50%, 60%, 70%, 80%, or 90%. The mass content of hydroxyl groups in PDMS500 can be 9%, and the mass content of hydroxyl groups in PDMS1000 can be 4%. This invention modifies polyurethane prepolymer resin by grafting hydroxyl-terminated polydimethylsiloxanes. Since hydroxyl-terminated polydimethylsiloxanes have a wide molecular weight range, different molecular weights exhibit significant performance differences and compatibility variations with polyurethane prepolymers. Furthermore, the viscosity of hydroxyl-terminated polydimethylsiloxanes themselves varies considerably. This invention strictly controls the molecular weight and dosage of hydroxyl-terminated polydimethylsiloxanes to ensure that the polydimethylsiloxane-modified polyurethane resin is a homogeneous resin with good flowability, guaranteeing the ability to spray-apply two-component coatings.

[0044] In this invention, the second grafting modification can be carried out in the presence of a catalyst; the second grafting modification can specifically be carried out by mixing the first polyurethane prepolymer resin, the modifier and the catalyst to carry out the second grafting modification.

[0045] In this invention, the mixing can specifically involve: adding a first polyurethane prepolymer resin, heating to the second grafting modification temperature under a protective atmosphere and stirring conditions, and adding a modifier and catalyst for mixing.

[0046] In this invention, the catalyst may include one or more of dibutyltin dilaurate, triethylenediamine, stannous octoate, and lead octoate. In this invention, the mass of the catalyst may be 0.003~0.03% of the mass of the polyurethane prepolymer resin, or 0.005~0.015%, specifically 0.01%.

[0047] In this invention, the temperature for the second grafting modification can be 75-85°C, 78-82°C, or even 80°C; the time for the second grafting modification can be 1-5 hours, or 2-4 hours, specifically 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours; the second grafting modification can be carried out under a protective atmosphere, which may include nitrogen, argon, or helium. In this invention, when the modifier is acrylic resin, the time for the second grafting modification can be further extended to 3-5 hours, and the second grafting modification yields acrylic-modified polyurethane resin; when the modifier is fluorocarbon resin, the time for the second grafting modification can be further extended to 2-4 hours, and the second grafting modification yields fluorocarbon-modified polyurethane resin; when the modifier is hydroxyl-terminated polydimethylsiloxane, the time for the second grafting modification can be further extended to 1-3 hours, and the second grafting modification yields polydimethylsiloxane-modified polyurethane resin.

[0048] To improve the adhesion of coatings to polar plastics and composite materials such as carbon fiber and glass fiber, acrylic resin can be added to polyurethane coatings. Meanwhile, pure acrylic resin (without solvents) has a high glass transition temperature, which improves the heat resistance of the coating after curing, making it suitable for the high-temperature environment of hydraulic structures in summer. In Chinese patent CN105623487A, component A uses hydroxyl acrylic resin and hydroxyl fluorocarbon resin with added diluents such as xylene and butyl acetate, while component B uses polyurethane prepolymer resin for curing. The high hydroxyl content in hydroxyl acrylic resin and hydroxyl fluorocarbon resin can easily lead to gelation with the highly reactive polyurethane prepolymer resin due to hydrogen bonding. This requires high-speed stirring (e.g., 1500 rpm) for a long time to break the gel and make it usable. To overcome this drawback, a diluent with a mass approximately equal to that of the hydroxyl acrylic resin and hydroxyl fluorocarbon resin is added to reduce the concentration of functional groups during the two-component mixing, enabling spray application. However, the above formulation results in a low solids content in the coating, and the curing process involves significant solvent evaporation, making it unsuitable for water-related projects in hydraulic structures. Furthermore, the cured coating becomes thinner, requiring more coats and increasing construction costs. Additionally, the cured film shrinks, easily causing cracking and edge curling, leading to protective failure. To address these issues, this invention modifies polyurethane prepolymer resin by grafting acrylic resin onto it. This allows the hydroxyl groups of the acrylic resin to react with the isocyanate groups of the polyurethane prepolymer resin, and a second grafting reaction is carried out at 80°C. This reduces the viscosity of the reactants and the effect of hydrogen bonding, preventing the formation of gels between the two groups at room temperature. By adding acrylic-modified polyurethane resin to the coating, this invention significantly improves the coating's adhesion to polar plastics and composite materials such as carbon fiber and glass fiber.

[0049] Many hydraulic structures are located in coastal areas with strong sunlight or high ion content, while others are in frigid northern regions. These locations place high demands on coatings for weather resistance, color retention, corrosion resistance, and freeze-thaw protection. Fluorocarbon coatings can address both of these needs. Chinese patent CN103555183A describes a method using polyurethane prepolymer modified with perfluoroalkyl ethanol, followed by chain extension with glycerol and UV curing to obtain a yellowing-resistant, weather-resistant fluorocarbon modified topcoat. Chinese patent CN106010175A uses perfluoropolyether diol and hydroxyl-functionalized fluorinated chain extenders in component A of the polyurethane prepolymer synthesis, and adds hydroxyl fluorocarbon resin to component B to obtain a bridge anti-icing type hand-scraped polyurea waterproof coating. This coating is highly efficient and environmentally friendly in de-icing, and also possesses corrosion resistance, wear resistance, aging resistance, and self-cleaning properties. The common feature of the two patents mentioned above is the use of a relatively large amount of perfluoropolyether alcohol. The cost of this raw material is far higher than that of commonly available fluorocarbon resins, which is detrimental to the large-scale, low-cost promotion of the product. Furthermore, the coating has low toughness, making it difficult to adapt to the displacement and deformation requirements of hydraulic structures. This invention modifies polyurethane prepolymer resin by grafting fluorocarbon resin, allowing for efficient spray application. Moreover, the raw materials used in this invention avoid the use of perfluoropolyether alcohol, resulting in lower costs while ensuring high coating toughness. By adding fluorocarbon-modified polyurethane resin to the coating, this invention significantly improves the coating's weather resistance, color retention, corrosion resistance, and freeze-thaw resistance.

[0050] Chinese patent CN115109510A uses polydimethylsiloxane-modified polyurethane acrylate oligomer UV-curing emulsion to improve the stain resistance of waterborne UV coatings. However, this invention is a solvent-based coating, and adding such an emulsion will lead to uneven coating layering. This invention uses polydimethylsiloxane-modified polyurethane resin prepared by grafting hydroxyl-terminated polydimethylsiloxane onto a polyurethane prepolymer resin. Adding the more hydrophobic polydimethylsiloxane-modified polyurethane resin to the coating can significantly increase the contact angle between the coating surface and water, and also enhance the thermal stability and leveling properties of the coating.

[0051] While each of the aforementioned patents has its own modification effect, they all have some defects such as poor water resistance, high cost, easy gelation, and single function. Furthermore, in actual construction and use, the environmental factors are complex and harsh, making it difficult for these single-modified coatings to achieve excellent comprehensive performance. The existing defects will result in a shorter service life of the coatings, making it impossible to achieve long-term water resistance, anti-peeling, gloss and color retention, and crack resistance. To obtain a coating with excellent overall performance, this invention employs synergistic modification with hydrogenated epoxy resin, silane coupling agent, acrylic resin, fluorocarbon resin, and hydroxyl-terminated polydimethylsiloxane. Hydrogenated epoxy resin enhances water resistance and eliminates the risk of yellowing; silane coupling agent improves adhesion; acrylic resin improves substrate adaptability and heat resistance; fluorocarbon resin improves weather resistance; and hydroxyl-terminated polydimethylsiloxane improves hydrophobicity. All modifiers are synthesized and grafted onto polyaspartic acid ester resin and polyurethane prepolymer, respectively, with strict control over the mass ratio of each modifier. This results in a homogeneous, sprayable two-component coating. The synergistic advantages of each modifier endow the coating with excellent overall performance, avoiding the weaknesses or deficiencies in other properties inherent in coatings modified by a single agent. Furthermore, the synthetic grafting modification method technically avoids gel formation and eliminates the need for large amounts of solvents, ensuring environmental friendliness. It also avoids the use of expensive raw materials, facilitating widespread application. Furthermore, this invention conducted rigorous comparative tests on the dosage of each modifier to determine the optimal dosage, resulting in optimal performance data for the coating in various aspects, including mechanical properties, water resistance, adhesion, weather resistance, freeze-thaw resistance, damp heat resistance, corrosion resistance, and hydrophobicity. Removing a certain synthetically modified resin leads to a decrease in one or more of the aforementioned properties, as shown in Comparative Examples 1-4. Similarly, reducing the dosage of a certain modifier during resin synthesis also results in a decrease in one or more of the aforementioned properties. Conversely, exceeding the dosage of a certain modifier during resin synthesis prevents the acquisition of a homogeneous, flowable modified resin, or may actually decrease one or more of the coating's properties, as shown in Comparative Examples 5-14. To verify the significant performance advantages of synergistic modification over single modification, comparative experiments were conducted using individual synthetically modified resins, confirming that one or more of the aforementioned properties significantly decreased, as shown in Comparative Examples 15-18.

[0052] In this invention, the preparation method of the first polyurethane prepolymer resin may include the following steps: mixing polyol and diisocyanate, and carrying out a polymerization reaction to obtain the first polyurethane prepolymer resin.

[0053] In this invention, the diisocyanate may include isophorone diisocyanate (IPDI) and / or hexamethylene diisocyanate (HDI). In this invention, the molar ratio of the hydroxyl group in the polyol to the NCO group in the diisocyanate may be 1:1.5~3.5, or 1:2~3, or even 1:2.5.

[0054] In this invention, the polyol may include diols and triols; the diol may include polyether diols (PPG type diols) and / or polytetrahydrofuran diols (PTMEG type diols). In this invention, the number-average molecular weight of the polyether diol may be 400-3000, or even 1000-2000; the polyether diol may include polypropylene glycol, which may specifically include one or more of DL400, DL1000, and DL2000, specifically DL1000. In this invention, the number-average molecular weight of the polytetrahydrofuran diol may be 500-3000, or even 1000-2000; the polytetrahydrofuran diol may include PTMEG1000 (BASF) and / or PTMEG2000 (BASF), specifically PTMEG2000. In this invention, the triol may include a polyether triol, the number average molecular weight of which may be 300-1000 or 300-450; the polyether triol may include CP300 (Dow Chemical).

[0055] In this invention, the polyol may comprise a first polyol mixture composed of polyether diol and polyether triol; or a second polyol mixture composed of polyether triol and polytetrahydrofuran diol; or a third polyol mixture composed of polyether diol, polytetrahydrofuran diol, and polyether triol. In this invention, the mass of polyether triol in the first polyol mixture may be 5-15% of the mass of polyether diol, or 8-12%, or even more, 10%; in this case, the diisocyanate may be isophorone diisocyanate. In this invention, the mass of polyether triol in the second polyol mixture may be 1-5% of the mass of polytetrahydrofuran diol, or 2-4%, or even more, 3%; in this case, the diisocyanate may be hexamethylene diisocyanate. In this invention, the mass of the polyether diol in the third polyol mixture can be more than 60% of the total mass of the polyether diol and polytetrahydrofuran diol, and can also be 60-90%, and can further be 70-80%; the mass of the polyether triol in the third polyol mixture can account for 3-7% of the total mass of the polyether diol and polytetrahydrofuran diol, and can also be 4-6%, and can further be 5%; the diisocyanate reacting with the third polyol mixture can be isophorone diisocyanate and hexamethylene diisocyanate, and the mass percentage of isophorone diisocyanate in the diisocyanate can be ≥70%, and can also be 70-90%, and can further be 80%. In this invention, the polyol is first dried before use. The drying process may include vacuum drying. The temperature of the vacuum drying may be 100~125℃, or 105~120℃, specifically 110℃. The vacuum drying time may be 1~5h, or 2~4h, specifically 2h. The vacuum drying pressure may be -0.080~-0.095MPa, or -0.083~-0.090MPa.

[0056] In this invention, the polymerization reaction can be carried out in the presence of a catalyst; specifically, the polymerization reaction can be carried out by mixing a polyol, a diisocyanate, and a catalyst. In this invention, the mixing can be: adding a polyol, and then adding the diisocyanate and catalyst under a protective atmosphere, at 60-70°C, and with stirring. In this invention, the catalyst can include one or more of dibutyltin dilaurate, triethylenediamine, stannous octoate, and lead octoate. In this invention, the mass of the catalyst can be 0.01-0.04% of the mass of the diisocyanate, or 0.015-0.035%, specifically 0.021%, 0.022%, or 0.028%.

[0057] In this invention, the polymerization reaction can be carried out in the presence of a solvent, or the resulting polymerization system can be diluted with a solvent after the polymerization reaction. The solvent may include one or more of butyl acetate, propylene glycol methyl ether acetate, and dimethylformamide, and may also include a first mixed solvent composed of dimethylformamide and butyl acetate, a second mixed solvent composed of dimethylformamide and propylene glycol methyl ether acetate, or a third mixed solvent composed of butyl acetate, propylene glycol methyl ether acetate, and dimethylformamide. In the first, second, and third mixed solvents, the mass percentage of dimethylformamide may be ≤15%, or may be 3-15%, specifically 3%, 5%, 8%, 10%, or 12%. In this invention, the solid content of the first polyurethane prepolymer resin may be 80-90%, or may be 82-88%, further 84-86%, specifically 85%.

[0058] In this invention, the temperature of the polymerization reaction can be 75~85℃, or 78~82℃, or even 80℃; the time of the polymerization reaction can be 2~4h, or 2.5~3.5h, or specifically 3h; the polymerization reaction can be carried out under a protective atmosphere, which may include nitrogen, argon or helium.

[0059] The present invention also provides a modified polyurethane resin prepared by the preparation method described above. When the modifier is an acrylic resin, the modified polyurethane resin is an acrylic modified polyurethane resin; when the modifier is a fluorocarbon resin, the modified polyurethane resin is a fluorocarbon modified polyurethane resin; when the modifier is a hydroxyl-terminated polydimethylsiloxane, the modified polyurethane resin is a polydimethylsiloxane modified polyurethane resin.

[0060] The present invention also provides a multi-component modified polyurethane weather-resistant and waterproof coating, comprising separately packaged component A and component B; Component A includes polyaspartic acid ester resin (denoted as the second polyaspartic acid ester resin) and the modified polyaspartic acid ester resin and polyetheramine described in the above technical solution; Component B includes a polyurethane prepolymer resin (denoted as the second polyurethane prepolymer resin) and the modified polyurethane resin described in the above technical solution. The modified polyurethane resin includes acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. When the multi-component modified polyurethane weather-resistant waterproof coating is used, the mass ratio of component A to component B is 1:1.1~1.7, and the molar amount of NCO groups in component B to the total molar amount of hydroxyl and amino groups in component A is 1.05~1.25:1.

[0061] In this invention, component A comprises a second polyaspartic ester resin, a modified polyaspartic ester resin, and a polyetheramine. In this invention, component A provides amino and hydroxyl functional groups.

[0062] In this invention, the secondary amino equivalent of the second polyaspartic ester resin can be 277~299, or 280~295, or even 285; the second polyaspartic ester resin may include F420 resin (Shenzhen Feiyang) and / or NH1420 resin (Bayer, now Covestro).

[0063] In this invention, the mass ratio of the second polyaspartic ester resin to the modified polyaspartic ester resin can be 3~6:4~7, or 3.5~5.5:4.5~6.5, or even 4~5:5~6, or specifically 3:7, 3.5:6.5, 4:6, 4.5:5.5 or 5:5.

[0064] In this invention, the polyetheramine may include one or more of polyetheramines T5000, T3000, and T403; the polyetheramine T5000 is a Huntsman trifunctional terminal amino polyetheramine with an average molecular weight of 5000 and a primary amino equivalent of 1904. In this invention, the mass of the polyetheramine may account for 25-40% of the total mass of NCO functional groups in component B, and may also be 25-35%, and may further be 30%. This invention improves the water resistance of the coating by adding polyetheramine to component A, which, in conjunction with other resins, forms a denser cross-linked network. Although the trifunctional polyetheramine T5000 added in this invention is a primary amine, its reactivity is significantly weaker than that of phenolic amines and alicyclic amines commonly used in hydraulic structures. By controlling the amount of polyetheramine T5000 added, this invention facilitates chain extension in the coating to form a denser cross-linked network without causing gelation.

[0065] In this invention, component A may further include excipients, which may include one or more of pigments, fillers, dispersants, defoamers, and thixotropic agents, and may also be pigments, fillers, dispersants, defoamers, and thixotropic agents.

[0066] In this invention, the pigments and fillers may include one or more of carbon black, titanium dioxide, quartz powder, barium sulfate, and silica powder. In this invention, the mass of the pigments and fillers may be 32.65-49.05% of the total mass of the resin in component A, or 35-45%, or even more, 40%. In this invention, the particle size of the quartz powder may be 2000-5000 mesh, or 2500-4000 mesh, or specifically 3000 mesh; the mass of the quartz powder may account for 8-14% of the total mass of the resin in component A, or 9-13%, or even more, 10-12%, or specifically 11%. In this invention, the barium sulfate may include precipitated barium sulfate; the particle size of the barium sulfate may be 2000-4000 mesh, or 2500-3500 mesh, specifically 3000 mesh; the mass of the barium sulfate may account for 12-18% of the total mass of the resin in component A, or 13-17%, further 14-16%, specifically 15%. In this invention, the mass of the carbon black may account for 0.25-0.35% of the total mass of the resin in component A, or 0.28-0.32%, further 0.3%. In this invention, the mass of the titanium dioxide may account for 12-16% of the total mass of the resin in component A, or 13-15%, further 14%. In this invention, the mass of the silica powder may account for 0.4-0.7% of the total mass of the resin in component A, or 0.45-0.65%, further 0.5-0.6%, specifically 0.55%.

[0067] In this invention, the mass of the dispersant can be 0.6-1.5% of the total mass of the resin in component A, or 0.8-1.3%, or even 1-1.2%. In this invention, the dispersant can include carbon black pigment dispersants, specifically one or more of Eucalyptus Chemical 680U, 580U, and BASF EFKA PX4310.

[0068] In this invention, the defoamer may account for 1-3% of the total mass of the resin in component A, and may also be 1.5-2.5%, or even 2%. In this invention, the defoamer may include non-silicone defoamers, specifically one or more of Yoka Chemicals P-590, P-595, and BYK Chemicals 1790.

[0069] In this invention, the thixotropic agent may account for 0.2-0.5% of the total mass of the resin in component A, and may also be 0.25-0.45%, further 0.3-0.4%, and specifically 0.35%. In this invention, the thixotropic agent may include solvent-based coating liquid thixotropic agents, and may specifically include BYK T430 and / or T410.

[0070] In this invention, component B comprises a second polyurethane prepolymer resin and a modified polyurethane resin, wherein the modified polyurethane resin comprises acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin.

[0071] In this invention, the solute-to-mass ratio of the polydimethylsiloxane-modified polyurethane resin and the second polyurethane prepolymer resin can be 1:6~10, or 1:7~9, or even 1:8. In this invention, the preparation method of the second polyurethane prepolymer resin is the same as that of the first polyurethane prepolymer resin, and will not be repeated here.

[0072] In this invention, the solute-to-mass ratio of the polydimethylsiloxane-modified polyurethane resin and the acrylic-modified polyurethane resin can be 1:3~5, or 1:3.5~4.5, or even 1:4. This invention, by adding acrylic-modified polyurethane resin to the coating, can significantly improve the coating's adhesion to polar plastics and composite materials such as carbon fiber and glass fiber.

[0073] In this invention, the mass ratio of the solute to the polydimethylsiloxane-modified polyurethane resin and the fluorocarbon-modified polyurethane resin can be 1:6~8, or 1:6.5~7.5, or even 1:7.

[0074] In this invention, when the multi-component modified polyurethane weather-resistant waterproof coating is used, the mass ratio of component A to component B can be 1:1.1~1.7, or 1:1.2~1.6, or even 1:1.3~1.5, or specifically 1:1.4; the molar ratio (R) of the NCO group in component B to the total molar ratio of hydroxyl and amino groups in component A can be 1.05~1.25:1, or 1.1~1.2:1, or even 1.15:1.

[0075] The surfaces of hydraulic structures often harbor silt, barnacles, algae, shellfish, and other microorganisms, as well as various types of debris, reducing their flow capacity. This invention, by adding fluorocarbon-modified polyurethane resin, improves the smoothness of the coating surface and provides a certain degree of self-cleaning function. Furthermore, by adding polydimethylsiloxane (PDMS)-modified polyurethane resin, which has stronger hydrophobicity, this invention increases the contact angle between the coating surface and water, and also enhances the coating's thermal stability and leveling properties.

[0076] In this invention, component B provides isocyanate groups. Component B used in this invention can provide good flexibility, water resistance, adhesion, weather resistance, freeze-thaw resistance, damp heat resistance and hydrophobicity for multi-component modified polyurethane weather-resistant and waterproof coatings.

[0077] This invention significantly improves the water resistance of coatings by grafting hydrogenated epoxy resin onto polyaspartic ester resin, enabling the coating to be used both above and below the water level fluctuation zone of hydraulic structures, i.e., for long-term immersion in water. Grafting a silane coupling agent onto the polyaspartic ester resin significantly enhances the interlayer adhesion between the coating and the inorganic interface, resulting in high bonding strength. The addition of acrylic-modified polyurethane resin allows the coating to be used on traditional concrete substrates as well as on polar plastics and composite materials such as carbon fiber and glass fiber, achieving bonding to various substrates. Simultaneously, it significantly improves the heat resistance of the coating, enabling it to withstand hot water and humid conditions. The addition of fluorocarbon-modified polyurethane resin significantly improves the weather resistance, color retention, and freeze-thaw resistance of the coating, making it suitable for use in areas with strong sunlight, such as coastal areas, and in frigid northern regions. It also reduces costs compared to perfluoropolyether alcohol, facilitating widespread adoption. This invention significantly improves the hydrophobicity of coatings by adding polydimethylsiloxane-modified polyurethane resin, reducing the adhesion of debris in water flow to the coating surface and extending the coating's service life. The multi-element modified polyurethane coating provided by this invention possesses excellent water resistance, corrosion resistance, roughness reduction, stain resistance, weather resistance, antifreeze (anti-ice adhesion) properties, damp heat resistance, and high toughness. Its superior overall performance effectively solves the problem of existing coatings having limited functionality or being unsuitable for the protection of hydraulic structures.

[0078] This invention also provides a method for preparing the multi-component modified polyurethane weather-resistant and waterproof coating described in the above technical solution, comprising the following steps: The polyaspartic acid ester resin, the modified polyaspartic acid ester resin, and the polyetheramine were mixed to obtain component A; Component B is obtained by mixing polyurethane prepolymer resin, acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. The components A and B are packaged separately to obtain a multi-component modified polyurethane weather-resistant waterproof coating.

[0079] This invention involves mixing polyaspartic acid ester resin, modified polyaspartic acid ester resin, and polyetheramine to obtain component A. In this invention, when component A further includes excipients, the mixing process involves mixing the polyaspartic acid ester resin, modified polyaspartic acid ester resin, polyetheramine, and excipients. Specifically, the mixing process may include: first mixing the polyaspartic acid ester resin, modified polyaspartic acid ester resin, polyetheramine, dispersant, defoamer, and thixotropic agent, and then second mixing with pigments and fillers. In this invention, the first mixing may include a first stirring mixing, wherein the stirring speed of the first stirring mixing may be 200~600 r / min, specifically 200 r / min, 300 r / min, 400 r / min, 500 r / min or 600 r / min; the first stirring mixing time may be 10~30 min, 11~15 min, specifically 10 min, 11 min, 13 min, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min or 30 min; the first stirring mixing may specifically be stirring at 200 r / min for 3 min, stirring at 400 r / min for 5 min, or stirring at 600 r / min for 3 min. In this invention, the second mixing may include a second stirring mixing, wherein the stirring speed of the second stirring mixing may be 500~800 r / min, specifically 500 r / min, 600 r / min, 700 r / min or 800 r / min; and the stirring mixing time is 2~5 h, specifically 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h.

[0080] This invention involves mixing polyurethane prepolymer resin, acrylic-modified polyurethane resin, fluorocarbon-modified polyurethane resin, and polydimethylsiloxane-modified polyurethane resin (referred to as the third mixture) to obtain component B. In this invention, the third mixture may include a third stirring mixture. The stirring speed of the third mixing may be 500-700 r / min, or 550-650 r / min, or even 600 r / min; the stirring time of the third mixing may be 30-60 min, or 30-40 min, specifically 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min.

[0081] This invention also provides the application of the multi-component modified polyurethane weather-resistant and waterproof coating described in the above-described technical solutions, or the multi-component modified polyurethane weather-resistant and waterproof coating prepared by the above-described technical solutions, in the protection of hydraulic structures, highways, or bridges; the application areas include areas with fluctuating water levels, long-term immersion areas, coastal areas with strong sunlight, and northern freeze-thaw zones. In this invention, the highway includes expressways.

[0082] In this invention, the mass ratio of component A to component B during the application process can be 1:1.1~1.7, or 1:1.2~1.6, or even 1:1.3~1.5, specifically 1:1.4. In this invention, the molar ratio (R) of the NCO groups in component B to the total molar ratio (R) of the hydroxyl and amino groups in component A during the application process can be 1.05~1.25:1, or 1.1~1.2:1, or even 1.15:1.

[0083] In this invention, the multi-component modified polyurethane weather-resistant waterproof coating can be applied by mixing component A and component B and then spraying. In this invention, the mixing can be achieved by adding component B to component A under stirring conditions.

[0084] The multi-component modified polyurethane coating provided by this invention uses acrylic modified polyurethane resin to improve the coating's substrate adaptability, fluorocarbon modified polyurethane resin to improve the coating's weather resistance, and polydimethylsiloxane modified polyurethane resin to improve the coating's hydrophobicity. The multi-component modified polyurethane coating has excellent water resistance, corrosion resistance, roughness reduction, stain resistance, weather resistance, antifreeze (anti-ice adhesion) properties, damp heat resistance, and high toughness. It has excellent comprehensive performance and can effectively solve the problem that existing coatings have single functions or cannot be applied to the protection of hydraulic structures. It is especially suitable for applications in hydraulic structures that require weather resistance, waterproofing, stain prevention, roughness reduction, corrosion protection, and resistance to summer damp heat and winter freezing.

[0085] To further illustrate the present invention, the modified polyaspartic acid ester resin, modified polyurethane resin, multi-component modified polyurethane weather-resistant and waterproof coating, their preparation methods and applications provided by the present invention are described in detail below with reference to embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0086] In the following examples, the polyetheramine is polyetheramine T5000, the carbon black is Origen FW200, the titanium dioxide is Chemours R960, the quartz powder has a particle size of 3000 mesh, the barium sulfate is 3000 mesh precipitated barium sulfate, and the silica powder is Wacker HDK H18. The dispersant is Ucarbochemical 680U, the defoamer is Ucarbochemical P-590, and the thixotropic agent is BYK T430.

[0087] In the following examples, the reactors used for the preparation of each resin are reaction vessels equipped with a PTFE stirrer, thermometer, and condenser.

[0088] Example 1 Synthesis of modified polyaspartic acid ester resin 1: F420 resin, EP4080-E resin and KH560 were added at a mass ratio of 300:60:15. Nitrogen gas was introduced, and the temperature was raised to 80℃ at 250 r / min. The reaction was maintained at this temperature for 3 h. After cooling to room temperature, modified polyaspartic acid ester resin 1 was obtained (resin solid content 100%, 0.1974 mol of secondary amine group and 0.0914 mol of hydroxyl group per 100 g of resin, and the composite equivalent of secondary amine and hydroxyl group was 346.26 g / eq). The resin was stored in a sealed container.

[0089] Synthesis of polyurethane prepolymer resin 1: DL400, DL1000, PTMEG2000 and CP300 were added, the temperature was raised to 110℃, vacuum was applied (pressure -0.080~-0.095MPa), and the temperature was maintained for 2h. The temperature was then restored to normal pressure, nitrogen gas was introduced, and the temperature was lowered to 60~70℃. IPDI and HDI were added at 300r / min, followed by dibutyltin dilaurate. The reaction mixture was allowed to exotherm up to 80℃ and maintained for 2h. Then, a mixed solvent of butyl acetate, propylene glycol methyl ether acetate and dimethylformamide was added, and the mixture was cooled to room temperature to obtain polyurethane prepolymer resin 1 (resin solid content of 85%, -NCO content of 9.74wt%), which was stored in a sealed container. The mass ratio of DL400, DL1000, PTMEG2000, CP300, IPDI, HDI and dibutyltin dilaurate is 17.39:104.33:52.16:8.69:108.92:27.23:0.03, the molar ratio of isocyanate groups and hydroxyl groups is 3:1, and the mass ratio of butyl acetate, propylene glycol methyl ether acetate and dimethylformamide is 39.38:11.25:5.63.

[0090] Synthesis of acrylic-modified polyurethane resin 1: Polyurethane prepolymer resin 1 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-B012 resin, WF-H6018 resin, and WF-H0821 resin were added, along with dibutyltin dilaurate. The reaction was maintained at this temperature for 4 h, and then cooled to room temperature to obtain acrylic-modified polyurethane resin 1 (resin solid content 79.92%, -NCO content 7.68 wt%), which was stored in a sealed container. The mass ratio of polyurethane prepolymer resin 1, WF-B012 resin, WF-H6018 resin, WF-H0821 resin, and dibutyltin dilaurate was 300:45:9:6:0.03.

[0091] Synthesis of fluorocarbon modified polyurethane resin 1: Polyurethane prepolymer resin 1 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-Q212 resin and dibutyltin dilaurate were added, and the reaction was maintained at this temperature for 2 h. After cooling to room temperature, fluorocarbon modified polyurethane resin 1 was obtained (resin solid content was 80.43%, -NCO content was 8.25 wt%). The mass ratio of polyurethane prepolymer resin 1, WF-Q212 resin and dibutyltin dilaurate was 300:45:0.03.

[0092] Synthesis of polydimethylsiloxane-modified polyurethane resin 1: Polyurethane prepolymer resin 1 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. PDMS500 and PDMS1000 were added, followed by dibutyltin dilaurate. The reaction was maintained at this temperature for 2 h, and then cooled to room temperature to obtain polydimethylsiloxane-modified polyurethane resin 1 (resin solid content of 87.50%, -NCO content of 5.44 wt%), which was stored in a sealed container. The mass ratio of polyurethane prepolymer resin 1, PDMS500, PDMS1000, and dibutyltin dilaurate was 300:30:30:0.03.

[0093] By mass, component A consists of: 300 parts modified polyaspartic ester resin, 200 parts F420 resin, 26.85 parts polyetheramine T5000 (35% of the mass of component B-NCO), 4 parts dispersant, 10.55 parts defoamer, 1.55 parts thixotropic agent, 1.55 parts carbon black, 73.75 parts titanium dioxide, 44.25 parts quartz powder, 77.50 parts barium sulfate, and 2.6 parts silica powder.

[0094] Preparation of Component A: Dispersant, defoamer, thixotropic agent, polyetheramine T5000, F420 resin and modified polyaspartic acid ester resin 1 were added sequentially. The mixture was stirred at 200 r / min for 3 min, at 400 r / min for 5 min and at 600 r / min for 3 min. Then, a mixture of carbon black, titanium dioxide, quartz powder, barium sulfate and silica powder was added under stirring at 500 r / min. The mixture was dispersed at 600 r / min for 3 h. Impurities were removed by filtration to obtain Component A, which was then stored in a sealed container.

[0095] Preparation of component B: Preparation of component B: Acrylic modified polyurethane resin 1, fluorocarbon modified polyurethane resin 1, polydimethylsiloxane modified polyurethane resin 1 and polyurethane prepolymer resin 1 were added according to a solute mass ratio of 20:35:5:40. Nitrogen gas was purged and the mixture was stirred at 600 r / min and room temperature for 30 min. Impurities were removed by filtration to obtain component B, which was then stored in a sealed container.

[0096] Preparation of a two-component, weather-resistant waterproof coating made of multi-component modified polyurethane: Component B was added to component A under a stirring condition of 500 r / min. After the addition of component B was complete, the mixture was stirred at 1000 r / min for 3 min to obtain the two-component coating. The mass ratio of component A to component B was 100:120.41, and R≈1.15.

[0097] The two-component coating was tested for the following properties, and the test results are shown in Table 1.

[0098] (1) Viscosity: The initial viscosity of the coating shall be determined by a rotational viscometer in accordance with the provisions of 5.1 in GB / T 2794-1995.

[0099] (2) Pot life at room temperature (23℃): According to the test method specified in GB / T 7123.1-2002, the viscosity is specified to be below 5000 mPa·s.

[0100] (3) Surface drying time at room temperature (23℃): Test the surface drying time of coatings according to Chapter 16 of GB / T 16777-2008.

[0101] (4) Tensile properties under room temperature air curing: Dumbbell type I specimens were prepared according to GB / T 528-2009. The specimens were cured at room temperature (23±2℃) and humidity 50±10% and the tensile properties were tested after 7 days and 28 days.

[0102] (5) Bonding strength: The bonding strength was tested according to the method specified in 7.9 of JC / T 2217-2014. First, KENENG epoxy interface agent was applied to the sample block. After it was surface dry, KENENG epoxy intermediate coating was applied. After it was surface dry, this modified polyurethane coating was applied. The following methods were used to cure the sample: ① Freeze-thaw cycle: The sample block was immersed in water and placed in a freezer at -20℃ along with the water. It was kept at this temperature for 8 hours. The frozen sample block was taken out and thawed at room temperature of 23±2℃ for 16 hours. One cycle was completed, and the cycle was repeated 30 times. ② Room temperature water immersion: The sample block was immersed in water and placed at room temperature of 23±2℃ for 30 days. ③ 50℃ hot water cycle: The sample block was immersed in water and placed in a 50℃ oven along with the water. It was kept at this temperature for 8 hours. The heated sample block was taken out and cooled by immersing in water at room temperature of 23±2℃ for 16 hours. One cycle was completed, and the cycle was repeated 30 times. ④ 70℃ Humidity and Heat Cycling: The samples were thoroughly soaked in water, removed from the water, and placed in a 70℃ oven for 6 hours. The heated samples were then removed and cooled by immersing in water at room temperature (23±2℃) for 18 hours. This completes one cycle, and 30 cycles are performed. ⑤ Room Temperature Air: The samples were placed in a curing chamber at room temperature (23±2℃) and humidity (50±10%) for 7 days. Throughout the entire process, the coatings on all five samples were required to show no peeling, cracking, or flaking. The adhesive strength was tested using a pull-out test.

[0103] (6) Corrosion resistance: According to GB / T19250-2013, test strips were prepared and subjected to heat treatment, alkali treatment and acid treatment respectively. After curing for 7 days, tensile properties were tested and retention rate was checked.

[0104] (7) Weather resistance: First, apply the KENENG epoxy interface agent to the sample block. After it is dry to the surface, apply the KENENG epoxy intermediate coating. After it is dry to the surface, apply the modified polyurethane coating. Prepare the sample block by curing it at room temperature for 7 days. Then, according to GB / T19250-2013, prepare the sample strip for testing the tensile properties. At the same time, put it into the artificial climate aging chamber and check whether the appearance of the sample block has good weather resistance. It is required that there is no yellowing or chalking after running for 1500 hours. The retention rate of the tensile properties of the sample strip is tested.

[0105] (8) Test the contact angle between the coating and pure water.

[0106] Table 1. Test results of multi-component modified polyurethane weather-resistant two-component waterproof coating

[0107] As shown in Table 1, the coating prepared in this embodiment has moderate viscosity, making it suitable for spraying. Its pot life and surface drying time meet the needs of daily construction. Test results for tensile strength and elongation at break indicate that the coating prepared in this embodiment has good flexibility, capable of adapting to the large displacement and deformation requirements of hydraulic structures. Under various curing conditions, the coating samples prepared in this embodiment showed no adhesion defects such as bulging or delamination. The adhesion strength met the project requirements: above 4.5 MPa after 7 days of air curing at room temperature, above 4.0 MPa after 30 days of immersion in water at room temperature, above 4.0 MPa after 30 freeze-thaw cycles, above 3.0 MPa after 30 cycles of hot water at 50℃, and above 2.5 MPa after 30 cycles of humid heat at 70℃. It exhibits strong water resistance and high adhesion strength, making it suitable for use in areas with fluctuating water levels and in areas above and below the water surface. After heat treatment, alkali treatment, acid treatment, and artificial climate aging, the coating prepared in this embodiment maintained a tensile strength retention rate of over 95% and an elongation at break retention rate of over 220%, meeting the standard requirements and indicating that the coating has good corrosion resistance. The coating prepared in this embodiment showed no chalking or yellowing after 1500 hours of artificial climate aging, indicating excellent weather resistance and suitability for applications requiring weather resistance, such as hydraulic structures. The coating prepared in this embodiment also exhibited a contact angle of 92.836° with pure water, greater than 90°, demonstrating good hydrophobicity and stain resistance.

[0108] Example 2 Synthesis of modified polyaspartic acid ester resin 2: F420 resin, EP4080-E resin and KH560 were added at a mass ratio of 300:45:12. Nitrogen gas was introduced, and the temperature was raised to 80℃ at 250 r / min. The reaction was maintained at this temperature for 2 h and then cooled to room temperature to obtain modified polyaspartic acid ester resin 2 (resin solid content 100%, 0.2305 mol of secondary amine group and 0.0729 mol of hydroxyl group per 100 g of resin, and the composite equivalent of secondary amine and hydroxyl group is 329.60 g / eq). The resin was stored in a sealed container.

[0109] Synthesis of polyurethane prepolymer resin 2: DL400, DL1000, DL2000 and CP300 were added, the temperature was raised to 110℃, vacuum was applied (pressure -0.080~-0.095MPa), and the temperature was maintained for 2 hours. The temperature was then restored to normal pressure, nitrogen gas was introduced, and the temperature was lowered to 60~70℃. IPDI and dibutyltin dilaurate were added at 300r / min. The reaction was allowed to exotherm to 80℃ and maintained for 2 hours. Then, a mixed solvent of butyl acetate and dimethylformamide was added, and the mixture was cooled to room temperature to obtain a diluted polyurethane prepolymer resin 2 solution (resin solid content of 82%, -NCO content of 7.77wt%), which was stored in a sealed container. The mass ratio of DL400, DL1000, DL2000, CP300, IPDI and dibutyltin dilaurate is 44.49:74.15:29.66:17.79:141.42:0.03, the molar ratio of isocyanate groups to hydroxyl groups is 2.2:1, and the mass ratio of butyl acetate to dimethylformamide is 59.4:8.1.

[0110] Synthesis of acrylic-modified polyurethane resin 2: Polyurethane prepolymer resin 2 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-B012 resin and WF-H0821 resin were added, followed by dibutyltin dilaurate. The reaction was maintained at this temperature for 4.5 h, and then cooled to room temperature to obtain acrylic-modified polyurethane resin 2 (resin solid content 78%, -NCO content 5.59 wt%), which was stored in a sealed container. The mass ratio of polyurethane prepolymer resin 2, WF-B012 resin, WF-H0821 resin, and dibutyltin dilaurate was 300:45:30:0.03.

[0111] Synthesis of fluorocarbon modified polyurethane resin 2: Polyurethane prepolymer resin 2 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-Q212 resin and dibutyltin dilaurate were added, and the reaction was maintained at this temperature for 2 h. After cooling to room temperature, fluorocarbon modified polyurethane resin 2 was obtained (resin solid content was 77.12%, -NCO content was 6.33 wt%). The mass ratio of polyurethane prepolymer resin 2, WF-Q212 resin and dibutyltin dilaurate was 300:54:0.03.

[0112] Synthesis of polydimethylsiloxane-modified polyurethane resin 2: Polyurethane prepolymer resin 2 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. PDMS500 and dibutyltin dilaurate were added, and the reaction was maintained at this temperature for 2.5 h. After cooling to room temperature, polydimethylsiloxane-modified polyurethane resin 2 (resin solid content was 84.35%, -NCO content was 3.86 wt%) was obtained and stored in a sealed container. The mass ratio of polyurethane prepolymer resin 2, PDMS500, and dibutyltin dilaurate was 300:45:0.03.

[0113] By mass, component A consists of: 325 parts modified polyaspartic ester resin, 175 parts F420 resin, 22.05 parts polyetheramine T5000 (27% of the mass of component B-NCO), 3.95 parts dispersant, 10.45 parts defoamer, 1.55 parts thixotropic agent, 1.55 parts carbon black, 73.1 parts titanium dioxide, 43.85 parts quartz powder, 76.80 parts barium sulfate, and 2.6 parts silica powder.

[0114] Preparation of Component A: Dispersant, defoamer, thixotropic agent, polyetheramine T5000, F420 resin and modified polyaspartic acid ester resin 2 were added sequentially. The mixture was stirred at 200 r / min for 3 min, at 400 r / min for 5 min and at 600 r / min for 3 min. Then, a mixture of carbon black, titanium dioxide, quartz powder, barium sulfate and silica powder was added under stirring at 500 r / min. The mixture was dispersed at 600 r / min for 3 h. Impurities were removed by filtration to obtain Component A, which was then stored in a sealed container.

[0115] Preparation of component B: Acrylic modified polyurethane resin 2, fluorocarbon modified polyurethane resin 2, polydimethylsiloxane modified polyurethane resin 2 and polyurethane prepolymer resin 2 were added according to the solute mass ratio of 20:30:5:45. Nitrogen gas was purged and the mixture was stirred at 600 r / min and room temperature for 30 min. Impurities were removed by filtration to obtain component B, which was then stored in a sealed container.

[0116] Preparation of a two-component, weather-resistant waterproof coating made of multi-component modified polyurethane: Component B was added to component A under stirring at 500 r / min. After the addition of component B was complete, the mixture was stirred at 1000 r / min for 3 min to obtain the two-component coating. The mass ratio of component A to component B was 100:165.61, and R≈1.20.

[0117] The performance of the multi-component modified polyurethane weather-resistant waterproof coating was tested according to the method in Example 1. The test results are shown in Table 2.

[0118] Table 2 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0119] As shown in Table 2, compared with Example 1, the coating prepared in Example 2 has a slightly lower tensile strength but a significantly improved elongation at break. This is because all polyols in component B are PPG polyether type, which has better flexibility. Furthermore, the -NCO content and solid content of component B are reduced, decreasing the hard segment content in the polyurethane molecular chain. The prepared coating is more suitable for applications requiring high elasticity. Under all curing conditions, the samples showed no adhesion defects such as bulging or delamination. The adhesion strength met the project requirements: above 4.5 MPa after 7 days of room temperature air curing, above 4.0 MPa after 30 days of room temperature water immersion, above 4.0 MPa after 30 freeze-thaw cycles, above 3.0 MPa after 30 cycles of 50℃ hot water cycling, and above 2.5 MPa after 30 cycles of 70℃ humid heat cycling. It exhibits strong water resistance and high adhesion strength, making it suitable for applications in areas with fluctuating water levels and in both vertical and horizontal regions. After heat treatment, alkali treatment, acid treatment, and artificial climate aging, the coating retains a tensile strength retention rate of over 85% and an elongation at break retention rate of over 250%, meeting the standard requirements and indicating good corrosion resistance. The coating prepared in this embodiment showed no chalking or yellowing after 1500 hours of artificial climate aging, demonstrating excellent weather resistance and suitability for applications requiring weather resistance, such as hydraulic structures. The coating prepared in this embodiment achieved a contact angle of over 95 degrees, exhibiting better hydrophobicity and stain resistance, and can be extended to prevent the adhesion of microorganisms such as kaempferia, shellfish, and algae to water conveyance structures in southern regions, thus reducing roughness.

[0120] Example 3 Synthesis of modified polyaspartic acid ester resin 3: F420 resin, EP4080-E resin and KH560 were added at a mass ratio of 300:75:18. Nitrogen gas was introduced, and the temperature was raised to 80℃ at 250 r / min. The reaction was maintained at this temperature for 3.5 h. After cooling to room temperature, modified polyaspartic acid ester resin 3 was obtained (resin solid content 100%, 0.1674 mol of secondary amine group and 0.1082 mol of hydroxyl group per 100 g of resin, and the composite equivalent of secondary amine and hydroxyl group was 362.84 g / eq). It was stored in a sealed container.

[0121] Synthesis of polyurethane prepolymer resin 3: PTMEG1000, PTMEG2000 and CP300 were added, the temperature was raised to 110℃, vacuum was applied (pressure -0.080~-0.095MPa), and the temperature was maintained for 2h. The temperature was then restored to normal pressure, nitrogen gas was introduced, and the temperature was lowered to 60~70℃. HDI and dibutyltin dilaurate were added at 300r / min. The reaction was allowed to exotherm to 80℃ and maintained for 2h. Then, a mixed solvent of butyl acetate, propylene glycol methyl ether acetate and dimethylformamide was added, and the mixture was cooled to room temperature to obtain a diluted polyurethane prepolymer resin 3 solution (resin solid content of 88%, -NCO content of 9.94wt%), which was stored in a sealed container. The mass ratio of PTMEG1000, PTMEG2000, CP300, HDI and dibutyltin dilaurate is 85.74:128.61:8.57:107.09:0.03, the molar ratio of isocyanate groups and hydroxyl groups is 3.3:1, and the mass ratio of butyl acetate, propylene glycol methyl ether acetate and dimethylformamide is 22.51:20.23:2.25.

[0122] Synthesis of acrylic-modified polyurethane resin 3: Polyurethane prepolymer resin 3 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-B012 resin and WF-H6018 resin were added, followed by dibutyltin dilaurate. The reaction was maintained at this temperature for 3.5 h, and then cooled to room temperature to obtain acrylic-modified polyurethane resin 3 (resin solid content 83.48%, -NCO content 8.20 wt%), which was stored in a sealed container. The mass ratio of polyurethane prepolymer resin 1, WF-B012 resin, WF-H6018 resin, WF-H0821 resin, and dibutyltin dilaurate was 300:30:15:0.03.

[0123] Synthesis of fluorocarbon modified polyurethane resin 3: Polyurethane prepolymer resin 3 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. WF-Q212 resin and dibutyltin dilaurate were added, and the reaction was maintained at this temperature for 2 h. After cooling to room temperature, fluorocarbon modified polyurethane resin 3 was obtained (resin solid content was 83.93%, -NCO content was 8.70 wt%). The mass ratio of polyurethane prepolymer resin 3, WF-Q212 resin and dibutyltin dilaurate was 300:36:0.03.

[0124] Synthesis of polydimethylsiloxane-modified polyurethane resin 3: Polyurethane prepolymer resin 3 was added, nitrogen gas was introduced, and the temperature was raised to 80℃ at 300 r / min. PDMS500 and PDMS1000 were added, followed by dibutyltin dilaurate. The reaction was maintained at this temperature for 2 h, and then cooled to room temperature to obtain polydimethylsiloxane-modified polyurethane resin 3 (resin solid content of 90%, -NCO content of 5.81 wt%), which was stored in a sealed container. The mass ratio of polyurethane prepolymer resin 3, PDMS500, PDMS1000, and dibutyltin dilaurate was 300:24:36:0.03.

[0125] By mass, component A consists of: 275 parts modified polyaspartic ester resin, 225 parts F420 resin, 21.75 parts polyetheramine T5000 (30% of the mass of component B-NCO), 3.95 parts dispersant, 10.45 parts defoamer, 1.55 parts thixotropic agent, 1.55 parts carbon black, 73.05 parts titanium dioxide, 43.80 parts quartz powder, 76.75 parts barium sulfate, and 2.6 parts silica powder.

[0126] Preparation of Component A: Dispersant, defoamer, thixotropic agent, polyetheramine T5000, F420 resin and modified polyaspartic acid ester resin 3 were added sequentially. The mixture was stirred at 200 r / min for 3 min, at 400 r / min for 5 min and at 600 r / min for 3 min. Then, a mixture of carbon black, titanium dioxide, quartz powder, barium sulfate and silica powder was added under stirring at 500 r / min. The mixture was dispersed at 600 r / min for 3 h. Impurities were removed by filtration to obtain Component A, which was then stored in a sealed container.

[0127] Preparation of component B: Acrylic modified polyurethane resin 3, fluorocarbon modified polyurethane resin 3, polydimethylsiloxane modified polyurethane resin 3 and polyurethane prepolymer resin 3 were added in a solute mass ratio of 20:40:5:35. Nitrogen gas was purged and the mixture was stirred at 600 r / min and room temperature for 30 min. Impurities were removed by filtration to obtain component B, which was then stored in a sealed container.

[0128] Preparation of a two-component, weather-resistant waterproof coating made of multi-component modified polyurethane: Component B was added to component A under stirring at 500 r / min. After the addition of component B was complete, the mixture was stirred at 1000 r / min for 3 min to obtain the two-component coating. The mass ratio of component A to component B was 100:111.05, and R≈1.10.

[0129] The performance of the multi-component modified polyurethane weather-resistant waterproof coating was tested according to the method in Example 1. The test results are shown in Table 3.

[0130] Table 3 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0131] As shown in Table 3, compared with Example 1, the coating sample prepared in Example 3 has a slightly lower elongation at break, but a significantly improved tensile strength. This is because almost all polyols in component B are PTMEG polytetrahydrofuran, which reduces the flexibility of the polymer molecular chain. Furthermore, the increased -NCO and solid content of component B increases the hard segment content in the polyurethane molecular chain, making it more suitable for applications requiring high strength, such as the protection of hydraulic concrete in areas with severe impact. Under all curing conditions, the samples showed no bonding defects such as bulging or delamination. The bonding strength met the project requirements: above 4.5 MPa after 7 days of air curing at room temperature, above 4.0 MPa after 30 days of immersion in water at room temperature, above 4.0 MPa after 30 freeze-thaw cycles, above 3.0 MPa after 30 cycles of hot water at 50°C, and above 2.5 MPa after 30 cycles of humid heat at 70°C. It exhibits strong water resistance and high bonding strength, making it suitable for applications in areas with fluctuating water levels, as well as areas above and below these levels. After heat treatment, alkali treatment, acid treatment, and artificial climate aging, the coating retains over 100% of its tensile strength and over 210% of its elongation at break, meeting the standard requirements and indicating good corrosion resistance. The coating prepared in this embodiment showed no chalking or yellowing after 1500 hours of artificial climate aging, demonstrating excellent weather resistance and suitability for applications requiring weather resistance, such as hydraulic structures. The coating prepared in this embodiment exhibits a contact angle of 90.424° with pure water, greater than 90°, indicating good hydrophobicity and stain resistance.

[0132] Comparative Example 1 The only difference from Example 1 is that the modified polyaspartic ester resin 1 in component A was removed, and F420 resin was used to fill the missing secondary amine and hydroxyl groups. The effect of not using modified polyaspartic ester resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 4.

[0133] Table 4 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0134] As shown in Table 4, among the five samples tested for the adhesive strength of the coatings prepared in this comparative example, those cured at room temperature for 7 days and subjected to 30 freeze-thaw cycles showed no peeling, cracking, or flaking. However, the coatings soaked in water at room temperature for 30 days, circulated in hot water at 50°C for 30 times, and subjected to humid heat cycles at 70°C for 30 times exhibited noticeable small bumps with a diameter of approximately 0.3 cm. The bump areas from the 50°C hot water cycle and the 70°C humid heat cycle were significantly larger than those from the room temperature water soak. This indicates that the water resistance of component A decreased significantly after the removal of modified polyaspartic acid ester resin 1, especially in the samples that underwent high-temperature treatment, where the adhesive strength of the coatings was significantly lower than the 2.5 MPa specified in the national standard. Furthermore, compared to Example 1, the absolute value of the adhesive strength of the coatings also decreased significantly. This phenomenon indicates that the water resistance of the samples decreased significantly after the removal of hydrogenated epoxy resin grafting in component A, and the adhesive strength of the samples decreased significantly after the removal of silane coupling agent grafting. Meanwhile, the contact angle between the coating and pure water was 80.374°, which is lower than 90°, indicating the absence of modified polyaspartic acid ester resin, which is also detrimental to the hydrophobicity of the coating.

[0135] Comparative Example 2 The only difference from Example 1 is that the acrylic-modified polyurethane resin 1 in component B was removed, and the missing isocyanate groups were filled with polyurethane prepolymer resin 1. The effect of not using acrylic-modified polyurethane resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 5.

[0136] Table 5 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0137] As shown in Table 5, in the adhesive strength test of the five samples of the coating prepared in this comparative example, the coatings cured at room temperature for 7 days, subjected to 30 freeze-thaw cycles, and soaked in water at room temperature for 30 days showed no peeling, cracking, or flaking. The coating surface after 30 cycles of hot water at 50℃ had small bubble-like bulges covering nearly half of its surface area, while the coating surface after 30 cycles of humid heat at 70℃ had large areas of small bulges with a diameter of about 0.3 cm. This indicates that after removing acrylic-modified polyurethane resin 1 from component B, the water resistance at high temperatures decreased significantly. The higher the temperature, the worse the water resistance, accompanied by a significant decrease in adhesive strength, which was lower than the 2.5 MPa specified in the national standard.

[0138] Comparative Example 3 The only difference from Example 1 is that the fluorocarbon-modified polyurethane resin 1 in component B was removed, and the missing isocyanate groups were filled with polyurethane prepolymer resin 1. The effect of not using fluorocarbon-modified polyurethane resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 6.

[0139] Table 6 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0140] As shown in Table 6, none of the five samples of the coating prepared in this comparative example, after 7 days of air curing at room temperature, 30 days of water immersion at room temperature, or 30 cycles of hot water at 50°C, exhibited peeling, cracking, or flaking. The coating surface after 30 cycles of humid heat at 70°C showed some small bubble-like bulges at the edges, while the coating surface after freeze-thaw cycles showed several large bulges with a diameter of about 1-2 cm. This indicates that the removal of fluorocarbon-modified polyurethane resin 1 from component B significantly reduced its resistance to freeze-thaw cycles and its resistance to 70°C humid heat cycles. Furthermore, although no obvious water resistance was observed in the samples after 50°C hot water cycling, the adhesive strength was significantly reduced. Moreover, none of the samples subjected to artificial climate aging showed chalking or yellowing after 1500 hours, indicating that the weather resistance of component B significantly decreased after the removal of fluorocarbon-modified polyurethane resin 1. In addition, the contact angle between the coating and pure water was tested and found to be 86.215°, which is lower than 90°, indicating the absence of fluorocarbon modified polyurethane resin 1, resulting in a decrease in the hydrophobicity of the coating.

[0141] Comparative Example 4 The only difference from Example 1 is that the polydimethylsiloxane-modified polyurethane resin 1 in component B was removed, and the missing isocyanate groups were filled with polyurethane prepolymer resin 1. The effect of not using polydimethylsiloxane-modified polyurethane resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 7.

[0142] Table 7 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0143] As shown in Table 7, the elongation at break of the coating decreased after removing polydimethylsiloxane-modified polyurethane resin 1 from component B. This is because polydimethylsiloxane has a silicone rubber structure, which can improve the low-temperature flexibility of the sample. No peeling, cracking, or flaking was observed in the adhesive strength tests of the five samples. However, the adhesive strength decreased after 30 cycles of hot water at 50℃ and 30 cycles of damp heat at 70℃, indicating that the thermal stability of the coating slightly decreased after removing the polydimethylsiloxane-modified polyurethane resin from component B. Furthermore, the contact angle between the coating and pure water was 71.492°, far lower than 90°, indicating that the absence of the polydimethylsiloxane-modified polyurethane resin led to a significant decrease in the hydrophobicity of the coating.

[0144] Comparative Example 5 The only difference from Example 1 is that the mass ratio of F420 resin to EP4080-E resin in the process of synthesizing modified polyaspartic ester resin 1 is 300:120. The effect of excessive EP4080-E resin on the coating performance was investigated. Each 100g of modified polyaspartic ester resin 1 contains 0.1061mol of secondary amine groups and 0.1429mol of hydroxyl groups, and the composite equivalent of secondary amine and hydroxyl groups is 401.61g / eq.

[0145] The two-component coating prepared in this comparative example could not reach full dryness within 30 hours after being applied to a concrete substrate. This was because the ratio of hydroxyl to amino groups in the modified polyaspartic acid ester resin was too high. Even when mixed with F420 resin and T5000 polyetheramine, the hydroxyl content was still too high, resulting in slow room temperature curing, which was unsuitable for actual construction in water conservancy projects.

[0146] Comparative Example 6 The only difference from Example 1 is that the mass ratio of F420 resin to EP4080-E resin in the process of synthesizing modified polyaspartic ester resin 1 is 300:30. The effect of insufficient EP4080-E resin on the coating performance was investigated. Every 100 grams of modified polyaspartic ester resin 1 contains 0.2550 mol of secondary amine groups and 0.0589 mol of hydroxyl groups, and the composite equivalent of secondary amine and hydroxyl groups is 318.57 g / eq.

[0147] The two-component coating prepared in this comparative example showed large and dense bubbles and bulges in the samples after soaking in water at room temperature for 30 days, circulating in hot water at 50℃ for 30 times, and circulating in humid heat at 70℃ for 30 times. This indicates that the reduction in the amount of EP4080-E resin is detrimental to the water resistance of the coating and makes it unsuitable for use in hydraulic structures.

[0148] Comparative Example 7 The only difference from Example 1 is that the mass ratio of F420 resin to KH560 in the process of synthesizing modified polyaspartic ester resin 1 is 300:30. The effect of excessive KH560 coupling agent on the coating performance was investigated. Each 100g of modified polyaspartic ester resin 1 contains 0.1880mol of secondary amine groups and 0.1128mol of hydroxyl groups, and the composite equivalent of secondary amine and hydroxyl groups is 332.45g / eq.

[0149] Component A, after dispersing pigments and fillers, exhibited obvious floating color and blooming. The paint film formed by the prepared two-component coating also showed slight floating color and blooming. Furthermore, the samples subjected to 30 freeze-thaw cycles, 30 days of soaking in water at room temperature, 30 cycles of hot water at 50℃, and 30 cycles of humid heat at 70℃ all showed large areas of dense bubbles and bulges. The water resistance of the two-component coating prepared in this comparative example was worse than that of comparative example 6, indicating that increasing the amount of KH560 coupling agent would reduce the water resistance of the coating and make it prone to floating color and blooming.

[0150] Comparative Example 8 The only difference from Example 1 is that in the process of synthesizing modified polyaspartic acid ester resin 1, the mass ratio of F420 resin to KH560 is 300:7.5. The effect of insufficient KH560 coupling agent on the coating performance was investigated. Every 100 grams of modified polyaspartic acid ester resin 1 contains 0.2101 mol of secondary amino groups and 0.0846 mol of hydroxyl groups, and the composite equivalent of secondary amino and hydroxyl groups is 339.33 g / eq.

[0151] The two-component coating prepared in this comparative example tended to detach from the underlying epoxy intermediate coat in certain areas after 30 cycles of hot water at 50°C and 30 cycles of humid heat at 70°C. This indicates that the reduced amount of KH560 coupling agent is detrimental to the adhesion performance of the coating under high-temperature conditions.

[0152] Comparative Example 9 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1, WF-B012 resin, WF-H6018 resin and WF-H0821 resin in the process of synthesizing acrylic modified polyurethane resin 1 is 300:90:18:12, to investigate the effect of excessive acrylic resin dosage on coating performance.

[0153] When the amount of acrylic resin is increased, a gel phenomenon occurs during the synthesis of acrylic-modified polyurethane resin 1. Even after adding a mixed solvent for dilution, the gel cannot be opened, and the curing agent cannot be used. The reason is that after increasing the amount of acrylic resin, the hydroxyl content increases, and the crosslinking network obtained by reacting with the isocyanate groups of the polyurethane prepolymer is too dense, so the resulting gel-like product cannot be dissolved in the diluent.

[0154] Comparative Example 10 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1, WF-B012 resin, WF-H6018 resin and WF-H0821 resin in the process of synthesizing acrylic modified polyurethane resin 1 is 300:22.5:4.5:3, to investigate the effect of insufficient acrylic resin dosage on coating performance.

[0155] After reducing the amount of acrylic resin, the adhesive strength of the two-component coating samples decreased in both the 50°C hot water cycling and 70°C humid heat cycling tests, reaching 2.879 MPa and 2.116 MPa respectively. Furthermore, the sample sample in the 70°C humid heat cycling test became slightly sticky on the surface during heat treatment. This is because acrylic resin is a polymer with good heat resistance, and reducing its amount will decrease the heat resistance of the coating, thus leading to a decrease in the adhesive strength of the coating at high temperatures.

[0156] Comparative Example 11 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1 to WF-Q212 resin in the process of synthesizing fluorocarbon modified polyurethane resin 1 is 300:90, and the effect of excessive fluorocarbon resin dosage on coating performance is investigated.

[0157] When the amount of fluorocarbon resin WF-Q212 is increased, the synthesized fluorocarbon modified polyurethane resin 1 remains in a flowing resin state during the 80℃ heat preservation stage. However, when cooled to room temperature, the viscosity reaches as high as 1792430 mPa·s, which is close to solid. If it is to be put into use, a large amount of mixed solvent needs to be added to make it into a flowing resin state. This will lead to a significant decrease in the tensile strength and solid content of the coating. It is unsuitable from both a performance and environmental protection perspective. The reason is that after the amount of fluorocarbon resin increases, the hydroxyl content increases. The crosslinking network obtained by reacting with the isocyanate groups of the polyurethane prepolymer is denser. The glass transition temperature is significantly higher than room temperature and significantly lower than the 80℃ synthesis heat preservation temperature. Therefore, it is more solid at room temperature and becomes a resin with good fluidity at high temperature.

[0158] Comparative Example 12 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1 to WF-Q212 resin in the process of synthesizing fluorocarbon modified polyurethane resin 1 is 300:22.5, and the effect of insufficient fluorocarbon resin dosage on coating performance is investigated.

[0159] After reducing the amount of fluorocarbon resin WF-Q212, the main impact is on the coating's resistance to artificial weathering. The coating's gloss, fading, and chalking are better than those of Comparative Example 3, but its gloss and color retention are worse than those of Example 1 at the same time, and chalking begins after 1240 hours.

[0160] Comparative Example 13 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1, PDMS500 and PDMS1000 in the process of synthesizing polydimethylsiloxane modified polyurethane resin 1 is 300:60:60, and the effect of excessive polydimethylsiloxane dosage on coating performance is investigated.

[0161] When the dosage of polydimethylsiloxane PDMS500 and PDMS1000 is increased, the synthesized polydimethylsiloxane-modified polyurethane resin has poor transparency, is more like an emulsion, and exhibits some layering. This is because polydimethylsiloxane has much better flexibility than polyurethane prepolymer, and the glass transition temperatures of the two are also very different. Therefore, when there are too many crosslinking points, phase separation is likely to occur, and the uniformity of the curing agent cannot be guaranteed. Thus, it is not suitable for use in coatings.

[0162] Comparative Example 14 The only difference from Example 1 is that the mass ratio of polyurethane prepolymer resin 1, PDMS500 and PDMS1000 in the process of synthesizing polydimethylsiloxane modified polyurethane resin 1 is 300:15:15, and the effect of insufficient polydimethylsiloxane dosage on coating performance is investigated.

[0163] Reducing the amount of polydimethylsiloxane PDMS500 and PDMS1000 will result in a significant decrease in the contact angle between the coating surface and water. The actual measured contact angle is 82.013°, which is lower than 90°. This indicates that reducing the amount of polydimethylsiloxane PDMS500 and PDMS1000 will reduce the hydrophobicity of the coating.

[0164] Comparative Example 15 Compared to Example 1, component B used only polyurethane prepolymer resin 1, removing acrylic modified polyurethane resin 1, fluorocarbon modified polyurethane resin 1, and polydimethylsiloxane modified polyurethane resin 1, and investigated the effect of a single modified polyaspartic ester resin 1 on the coating performance. The test results of the two-component coating are shown in Table 8.

[0165] Table 8 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0166] Based on the performance data in Table 8, the main effects of a single modified polyaspartic acid ester resin 1 on the coating performance are: 1. Decreased water resistance, accompanied by a decrease in adhesive strength. Samples subjected to 30 freeze-thaw cycles showed several large bulges with diameters of approximately 0.5-1.5 cm on their surface. Samples subjected to 30 cycles of hot water at 50℃ and 30 cycles of humid heat at 70℃ showed a large area of ​​densely packed small bulges with diameters of approximately 0.5 cm on their surface. Furthermore, the adhesive strength of the coating under these three curing conditions was less than 2.5 MPa. This is likely related to the lack of acrylic-modified polyurethane resin 1 and fluorocarbon-modified polyurethane resin 1. 1. The absence of acrylic-modified polyurethane resin 1 leads to a decrease in the coating's heat resistance, and the absence of fluorocarbon-modified polyurethane resin 1 leads to a decrease in the coating's freeze-thaw resistance. 2. After heat treatment, alkali treatment, acid treatment, and artificial weathering, the retention rate of tensile strength and elongation at break of the coating also decreases. This is because fluorocarbon resin has good chemical stability and can improve the coating's corrosion resistance. The absence of fluorocarbon-modified polyurethane resin 1 is the main reason for the decrease in the retention rate of tensile strength and elongation at break. 3. The artificial weathering performance cannot reach 1500 hours without yellowing or chalking. This is because fluorocarbon resin and acrylic resin can significantly improve the coating's weather resistance. The absence of acrylic-modified polyurethane resin 1 and fluorocarbon-modified polyurethane resin 1 leads to a significant shortening of the coating's artificial weathering resistance time. 4. The contact angle with pure water decreases significantly, far below 90°. This is caused by the absence of polydimethylsiloxane-modified polyurethane resin 1, resulting in a significant deterioration in the coating's hydrophobicity and scale resistance. In summary, using a single modified polyaspartic ester resin 1 for modification will result in a significant decrease in the coating's water resistance, adhesion, corrosion resistance, weather resistance, and hydrophobicity, failing to achieve the effect of Example 1.

[0167] Comparative Example 16 Compared to Example 1, component A removed modified polyaspartic ester resin 1 and used only F420 resin; component B removed polyurethane prepolymer resin 1, fluorocarbon modified polyurethane resin 1, and polydimethylsiloxane modified polyurethane resin 1. The effect of a single acrylic modified polyurethane resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 9.

[0168] Table 9 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0169] From the performance data in Table 9, the main effects of a single acrylic-modified polyurethane resin 1 on the coating performance are: 1. Decreased water resistance, accompanied by a decrease in adhesive strength. Samples subjected to 30 freeze-thaw cycles showed several large bulges with a diameter of approximately 0.5-1.5 cm on their surface. Samples soaked in water at room temperature for 30 days and subjected to 30 cycles of hot water at 50℃ showed a large area of ​​densely packed small bulges with a diameter of approximately 0.5 cm on their surface. Furthermore, the adhesive strength of the coating under these three curing conditions was less than 2.5 MPa. This is mainly due to the absence of modified polyaspartic acid ester resin 1. The absence of hydrogenated epoxy resin leads to water insensitivity in the coating under various curing conditions. The absence of silane coupling agent leads to a decrease in adhesive strength. The relatively good water resistance of the sample surface after 30 cycles of 70℃ damp heat is because acrylic-modified polyurethane resin 1 improves the heat resistance of the coating. During the cycling process, the sample... 1. When the sample block is removed and placed in an oven for heat treatment at 70℃, the moisture absorbed by the sample block and the coating is removed, reducing the formation of blistering. 2. After heat treatment, alkali treatment, acid treatment, and artificial weathering, the retention rate of tensile strength and elongation at break of the coating also decreased. This is because fluorocarbon resin and epoxy resin can improve the corrosion resistance of the coating, while the absence of modified polyaspartic acid ester resin 1 and fluorocarbon modified polyurethane resin 1 led to a decrease in the corrosion resistance of the coating. 3. The artificial weathering performance could not reach 1500 hours without yellowing or chalking. This is because fluorocarbon resin can significantly improve the weather resistance of the coating, while the absence of fluorocarbon modified polyurethane resin 1 led to a significant shortening of the coating's artificial weathering resistance time. 4. The contact angle with pure water decreased significantly, far below 90°. This was caused by the absence of polydimethylsiloxane modified polyurethane resin 1, resulting in a significant deterioration in the hydrophobicity and scale resistance of the coating. In summary, using a single acrylic-modified polyurethane resin 1 for modification will result in a significant decrease in the coating's water resistance, adhesion, corrosion resistance, weather resistance, and hydrophobicity, failing to achieve the effect of Example 1.

[0170] Comparative Example 17 Compared to Example 1, component A removed modified polyaspartic ester resin 1 and used only F420 resin; component B removed polyurethane prepolymer resin 1, acrylic modified polyurethane resin 1, and polydimethylsiloxane modified polyurethane resin 1. The effect of a single fluorocarbon modified polyurethane resin 1 on the coating performance was investigated. The test results of the two-component coating are shown in Table 10.

[0171] Table 10 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0172] From the performance data in Table 10, the main effects of a single acrylic-modified polyurethane resin 1 on the coating performance are: 1. Decreased water resistance, accompanied by a decrease in adhesive strength. Samples soaked in water at room temperature for 30 days, circulated in hot water at 50℃ for 30 times, and circulated under humid heat at 70℃ for 30 times exhibited large areas of bulges with a diameter of approximately 0.5 cm on their surface. The higher the temperature, the denser the bulges. Samples subjected to 30 freeze-thaw cycles maintained relatively good water resistance and high adhesive strength. This is mainly because hydrogenated epoxy resin increases the coating's water resistance, silane coupling agent improves the coating's adhesive strength, and fluorocarbon resin improves the coating's freeze-thaw resistance. Therefore, removing the modified polyaspartic acid ester resin 1 and using only a single fluorocarbon-modified polyurethane resin 1 to cure the coating results in samples with poor water resistance, decreased adhesive strength, but good freeze-thaw resistance. This is also related to the freeze-thaw cycle... 1. The sample was frozen for about half the time, which is related to the less stringent requirements for the continuous water resistance of the coating; 2. After heat treatment, alkali treatment, and acid treatment, the retention rate of tensile strength and elongation at break of the coating also decreased. This is because hydrogenated epoxy resin can improve the corrosion resistance of the coating, so removing modified polyaspartic acid ester resin 1 led to a decrease in the retention rate of tensile strength and elongation at break. However, fluorocarbon resin can improve the weather resistance of the coating, so after using a large amount of fluorocarbon modified polyurethane resin 1, the retention rate of tensile strength and elongation at break after artificial weathering actually increased; 3. The contact angle with pure water decreased significantly, slightly below 90°. This is because fluorocarbon resin itself has good hydrophobicity, but compared with polydimethylsiloxane, its hydrophobicity is significantly worse, so the contact angle is lower. In summary, using a single fluorocarbon modified polyurethane resin 1 for modification will lead to a significant decrease in the water resistance, adhesion, corrosion resistance, and heat resistance of the coating, and cannot achieve the effect of Example 1.

[0173] Comparative Example 18 Compared to Example 1, component A removed modified polyaspartic ester resin 1 and used only F420 resin; component B removed polyurethane prepolymer resin 1, acrylic modified polyurethane resin 1, and fluorocarbon modified polyurethane resin 1. The effect of polydimethylsiloxane modified polyurethane resin 1 alone on the coating performance was investigated. The test results of the two-component coating are shown in Table 11.

[0174] Table 11 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0175] From the performance data in Table 11, the main effects of a single acrylic-modified polyurethane resin 1 on the coating performance are: 1. Decreased water resistance, accompanied by a decrease in adhesive strength. Except for samples cured at room temperature for 7 days, samples soaked in water at room temperature for 30 days, subjected to 30 freeze-thaw cycles, 30 cycles of hot water at 50℃, and 30 cycles of humid heat at 70℃ all exhibited large, dense bulges of varying sizes. This is because the removal of modified polyaspartic acid ester resin 1 resulted in the absence of hydrogenated epoxy resin, leading to decreased water resistance; the absence of silane coupling agent led to decreased adhesive strength. Furthermore, the strength of the coating cured with a single polydimethylsiloxane-modified polyurethane resin 1 was low, especially the tensile strength after 7 days, which was below 8 MPa. 1. Insufficiently dense cross-linked networks lead to water insensitivity in the early stages of various curing methods. As curing time increases, the adhesion between the coating and the substrate deteriorates, ultimately resulting in easy detachment of the coating from the substrate during adhesion strength testing. 2. After heat treatment, alkali treatment, acid treatment, and artificial weathering, the retention rate of tensile strength and elongation at break also decreases significantly. The absence of hydrogenated epoxy resin and fluorocarbon resin, which enhance the coating's corrosion resistance, causes samples with inherently low strength to lose more mechanical properties in various corrosion resistance tests. 3. The artificial weathering performance fails to achieve 1500 hours of no yellowing or chalking, directly related to the lack of weather-resistant components such as fluorocarbon resin and acrylic resin. In conclusion, modification with a single polydimethylsiloxane-modified polyurethane resin 1 results in a significant decrease in the coating's water resistance, adhesion, corrosion resistance, heat resistance, and weather resistance, failing to achieve the effects of Example 1.

[0176] Comparative Example 19 In the two-component unmodified polyurethane coating, component A uses 100% F420 resin, and component B uses 100% polyurethane prepolymer resin 3 (the polyurethane prepolymer resin in Example 3). The specific formulation is as follows: By mass parts, component A: 500 parts F420 resin, 5 parts dispersant, 10 parts defoamer, 1.5 parts thixotropic agent, 1.5 parts carbon black, 70 parts titanium dioxide, 55 parts quartz powder, 75 parts barium sulfate, and 2.75 parts silica fume. Component B is 100% polyurethane prepolymer resin 3 and does not require dispersion mixing. When using, the mass ratio of component A to component B is 100:126.96, R≈1.10. The test results of the two-component coating are shown in Table 12.

[0177] Table 12 Test Results of Multi-component Modified Polyurethane Weather-resistant Two-component Waterproof Coating

[0178] The two-component unmodified polyurethane coating prepared using Comparative Example 19 was used in the reinforcement project of the fourth water diversion hub of the main canal of the Hetao Irrigation District in Inner Mongolia. It was used for one year after spraying and was only irrigated twice during the period of use. See the figure for a picture of the actual product.

[0179] From the data in Table 12, compared with Example 3, the unmodified two-component system has the following main shortcomings: 1. Decreased water resistance, accompanied by a decrease in adhesive strength. Except for the samples cured at room temperature for 7 days, the samples cyclically heated to 50°C for 30 times and to 70°C for 30 times exhibited large, dense bulges of varying sizes. The samples cyclically frozen for 30 times had several bulges with a diameter of 0.5-1 cm. Although the samples soaked in water at room temperature for 30 days did not show obvious bulges, the surface damage after the pull-out test was less severe than that of the samples cured at room temperature for 7 days, and the adhesive strength was ≤2.5 MPa. This is related to the decrease in water resistance and adhesive strength due to the lack of modified polyaspartic acid ester resin; it is also related to the decrease in heat resistance and adhesiveness due to the lack of acrylic modified polyurethane resin; and it is also related to the decrease in freeze-thaw resistance due to the lack of fluorocarbon modified polyurethane resin. Figure 1 It can be seen that there are many areas of paint peeling, missing parts, flaking, and blistering; 2. After heat treatment, alkali treatment, acid treatment, and artificial climate aging, although the retention rates of tensile strength and elongation at break of the paint meet the standard requirements, the values ​​are significantly lower than in Example 3. This is related to the decrease in corrosion resistance after removing hydrogenated epoxy resin, the decrease in heat resistance after removing acrylic resin, and the decrease in weather resistance after removing fluorocarbon resin. Hydraulic structures are immersed in water, so they have certain requirements for corrosion resistance. The flowing water may contain some slightly corrosive substances such as acids and alkalis. Figure 1 The closer to the water, the more obvious the paint loss; 3. The artificial climate aging performance simply cannot achieve 1500 hours of no yellowing or chalking, which is directly related to the lack of weather-resistant components such as fluorocarbon resin and acrylic resin. Figure 1 It can be seen that after only one year of use following the spraying application, the paint lacks gloss, has faded, and some areas have yellowed. 4. The contact angle with pure water is far below 90°. This is mainly related to the lack of polydimethylsiloxane in the paint, which significantly reduces its hydrophobicity. This makes it easier for impurities and debris in the water to adhere to areas with fluctuating water levels and below, which will corrode the coating surface and reduce its service life.

[0180] The two-component unmodified polyurethane coating prepared using Comparative Example 19 was used in the reinforcement project of the fourth water diversion hub of the main canal of the Hetao Irrigation District in Inner Mongolia. After one year of use and only two water immersions during the period of use, the following defects were observed: the water resistance and adhesion of the coating were not ideal; the coating near the water surface peeled off, was missing, flaked, and bulged; the parts immersed in water should have suffered more severe damage; the coating as a whole lost its luster and faded in color; the upper part, which was far from the water surface and frequently exposed to wind and sun, had powdered, peeled off, and yellowed, and its original color could not be seen, thus losing its protective function.

[0181] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a modified polyaspartic acid ester resin, characterized in that, Includes the following steps: Polyaspartic acid ester resin, hydrogenated epoxy resin and silane coupling agent are mixed and grafted under a protective atmosphere to obtain modified polyaspartic acid ester resin. The grafting modification is performed at a temperature of 60-90℃ for 2-4 hours. The silane coupling agent includes one or more of KH560, KH561, KH550, KH-792, KH-602 and KH570; The hydrogenated epoxy resin accounts for 10-30% of the mass of the polyaspartic acid ester resin; The mass ratio of the hydrogenated epoxy resin to the silane coupling agent can be 3.5~4.5:

1.

2. The modified polyaspartic acid ester resin prepared by the method described in claim 1.

3. A method for preparing a modified polyurethane resin, comprising the following steps: Polyurethane prepolymer resin and modifier are mixed and grafted to obtain modified polyurethane resin. The modifier includes acrylic resin, fluorocarbon resin, or hydroxyl-terminated polydimethylsiloxane.

4. The preparation method according to claim 3, characterized in that, The acrylic resin accounts for 10-30% of the mass of the polyurethane prepolymer resin; The fluorocarbon resin accounts for 5-20% of the mass of the polyurethane prepolymer resin; The hydroxyl-terminated polydimethylsiloxane accounts for 10-20% of the mass of the polyurethane prepolymer resin; The grafting modification temperature is 75~85℃, and the time is 1~5h.

5. The modified polyurethane resin prepared by the method according to claim 3 or 4, characterized in that, When the modifier is acrylic resin, the modified polyurethane resin is acrylic modified polyurethane resin; When the modifier is a fluorocarbon resin, the modified polyurethane resin is a fluorocarbon modified polyurethane resin. When the modifier is hydroxyl-terminated polydimethylsiloxane, the modified polyurethane resin is a polydimethylsiloxane-modified polyurethane resin.

6. The application of the modified polyaspartic acid ester resin of claim 2 or the modified polyurethane resin of claim 5 in coatings.

7. A multi-component modified polyurethane weather-resistant and waterproof coating, characterized in that, Includes separately packaged components A and B; Component A includes polyaspartic acid ester resin, the modified polyaspartic acid ester resin according to claim 2, and polyetheramine; Component B comprises a first polyurethane prepolymer resin and the modified polyurethane resin according to claim 5, wherein the modified polyurethane resin comprises acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. When the multi-component modified polyurethane weather-resistant waterproof coating is used, the mass ratio of component A to component B is 1:1.1~1.7, and the molar amount of NCO groups in component B to the total molar amount of hydroxyl and amino groups in component A is 1.05~1.25:

1.

8. The multi-component modified polyurethane weather-resistant and waterproof coating according to claim 7, characterized in that, In component B, the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and the first polyurethane prepolymer resin is 1:6~10, the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and acrylic acid-modified polyurethane resin is 1:3~5, and the mass ratio of the solutes of polydimethylsiloxane-modified polyurethane resin and fluorocarbon-modified polyurethane resin is 1:6~8. The mass ratio of polyaspartic acid ester resin to modified polyaspartic acid ester resin in component A is 3~6:4~7; The mass of the polyetheramine accounts for 25-40% of the total mass of the NCO functional groups in component B.

9. The multi-component modified polyurethane weather-resistant and waterproof coating according to claim 7 or 8, characterized in that, Component A also includes excipients, which include one or more of pigments, fillers, dispersants, defoamers, and thixotropic agents.

10. The method for preparing the multi-component modified polyurethane weather-resistant and waterproof coating according to any one of claims 7 to 9, characterized in that, Includes the following steps: The first polyaspartic ester resin, the modified polyaspartic ester resin, and the polyetheramine were mixed to obtain component A; Component B is obtained by mixing polyurethane prepolymer resin, acrylic modified polyurethane resin, fluorocarbon modified polyurethane resin and polydimethylsiloxane modified polyurethane resin. The components A and B are packaged separately to obtain a multi-component modified polyurethane weather-resistant waterproof coating.

11. The application of the multi-component modified polyurethane weather-resistant and waterproof coating according to any one of claims 7 to 9 or the multi-component modified polyurethane weather-resistant and waterproof coating prepared by the preparation method according to claim 10 in the protection of hydraulic structures, highways or bridges; The application areas include areas with fluctuating water levels, areas that have been submerged for a long time, coastal areas with strong sunlight, and northern freeze-thaw zones.

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