Hydrogen bond self-repairing organic-inorganic waterproof concrete coating and preparation method thereof

Abstract

This invention discloses a hydrogen-bonded self-healing organic-inorganic waterproof concrete coating and its preparation method. The coating consists of liquid component A and powder component B, mixed at a mass ratio of 0.9–1.1:1. Liquid component A contains functionalized polyacrylic acid emulsion, water, film-forming aids, and additives. Powder component B contains cement, modified zeolite molecular sieve, silica fume, quartz powder, quartz sand, heavy calcium carbonate, and additives. The emulsion chains contain hydroxyl, amide, and ester carbonyl groups, and the modified zeolite molecular sieve surface is simultaneously grafted with polar functional groups and hydrophobic segments. The preparation method sequentially includes zeolite molecular sieve activation, equal-volume impregnation modification, liquid component dispersion, powder component dry mixing, and liquid-powder mixing. It possesses both excellent waterproof performance and self-healing ability, making it suitable for waterproof protection of concrete structure surfaces.

Description

Technical Field

[0001] This invention relates to the field of concrete coating technology, and in particular to a hydrogen bond self-healing organic-inorganic waterproof concrete coating and its preparation method. Background Technology

[0002] Concrete structures are susceptible to continuous exposure to rainwater, groundwater, and humid environments during long-term service. Moisture can migrate inwards through capillary pores, microcracks, and interface defects on the concrete surface, leading to steel corrosion, freeze-thaw damage, and a decrease in overall durability. To improve the impermeability and durability of concrete substrates, constructing a continuous and dense waterproof coating on its surface is a commonly used protective measure in engineering. Among these, organic-inorganic composite waterproof coatings combine the flexibility and adhesion of organic polymer film-forming materials with the strength and weather resistance of inorganic cementitious materials, making them highly valuable in the field of concrete protection.

[0003] Existing organic-inorganic composite waterproof coatings generally employ a two-component system, combining polymer emulsions with cement, fillers, and additives. While this type of system can balance flexibility and strength to a certain extent, it still has some shortcomings in practical use: Firstly, the organic and inorganic phases differ in polarity, surface energy, and film-forming / hydration behavior, resulting in limited interfacial compatibility. Under conditions of wet-dry cycles, temperature changes, and substrate deformation, the coating film is prone to interfacial micro-cracks, blistering, or peeling, thus affecting long-term adhesion and waterproofing performance. Secondly, once micro-cracks develop during service, the coating film typically lacks effective self-repair capabilities, and these cracks can easily evolve into moisture penetration channels, leading to a decline in protective performance.

[0004] To improve the bonding between organic and inorganic interfaces, existing technologies include mineral filler modification or silane coupling agent surface treatment. Zeolite molecular sieves, due to their large specific surface area and numerous surface hydroxyl groups, can be used as functional fillers to enhance interfacial interactions. However, unmodified zeolite molecular sieves are highly hydrophilic, and direct introduction into coating systems may adversely affect impermeability. Furthermore, when using a single type of silane for surface treatment, it is often difficult to simultaneously achieve both interfacial interaction with the polymer matrix and barrier effect against moisture migration. In addition, while existing waterproof coatings employ microencapsulation and reversible crack repair approaches, there is still room for improvement in terms of compatibility with cement-based inorganic components, formulation complexity, and ease of engineering application.

[0005] Therefore, it is necessary to provide an organic-inorganic waterproof concrete coating and its preparation method that takes into account the compatibility of the organic-inorganic interface, impermeability, and self-healing ability of cracks. Summary of the Invention

[0006] To address the technical problems of insufficient interfacial compatibility between the organic and inorganic phases and lack of self-healing ability after microcracks appear in existing organic-inorganic waterproof concrete coatings, this invention aims to overcome the shortcomings of poor interfacial compatibility between the organic and inorganic phases, lack of self-healing ability for microcracks in the coating, and low waterproof durability in existing organic-inorganic waterproof concrete coatings. This invention provides an intrinsically self-healing organic-inorganic waterproof concrete coating based on hydrogen bond networks, along with its preparation method. This coating possesses excellent waterproof performance, interfacial bonding strength, and self-healing ability, and its preparation process is simple and cost-effective, making it suitable for waterproof protection of concrete structure surfaces. This invention provides a hydrogen-bonded self-healing organic-inorganic waterproof concrete coating and its preparation method.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a hydrogen bond self-healing organic-inorganic waterproof concrete coating, wherein the coating is composed of liquid A and powder B mixed in a mass ratio of (0.9-1.1):1.

[0008] The liquid component A comprises, by weight, 55-70 parts of functionalized polyacrylic acid emulsion, 8-18 parts of water, 1-3 parts of film-forming aid, 0.2-0.8 parts of dispersant, 0.1-0.6 parts of wetting agent, 0.1-0.5 parts of defoamer, 0.2-1.0 parts of thickener, and 0.1-0.3 parts of preservative.

[0009] The powder B, by weight, comprises: 30-45 parts cement, 5-15 parts modified zeolite molecular sieve, 2-8 parts silica fume, 8-18 parts quartz powder, 15-30 parts quartz sand, 8-20 parts heavy calcium carbonate, 0.2-1.0 parts cellulose ether, 0.2-1.0 parts water-reducing agent, and 0.1-0.5 parts defoamer.

[0010] The functionalized polyacrylic acid emulsion is obtained by copolymerizing soft monomers, hard monomers, acidic monomers, hydroxyl monomers, amide monomers, and crosslinking monomers. The resulting polymer chains contain hydroxyl, amide, and ester carbonyl groups. This invention introduces these three types of polar groups simultaneously into the copolymer molecular chains, forming a multi-layered hydrogen bond interaction network within the coating film. Specifically, the hydroxyl group can act as both a hydrogen bond donor and acceptor, the N-H in the amide group can form N-H···O=C hydrogen bonds with the carbonyl oxygen, and the ester carbonyl group provides additional hydrogen bond acceptor sites. When the coating film develops microcracks under external force, the broken hydrogen bonds on the crack surface can recombine under temperature or humidity-driven conditions. Through the thermal motion of the chain segments, the polymer chains on both sides of the crack re-overlap, thereby achieving intrinsic self-healing of the coating film.

[0011] Further, the soft monomer is selected from at least one of butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA), and the hard monomer is methyl methacrylate. The glass transition temperature of the homopolymer of butyl acrylate is approximately -54°C, and that of the homopolymer of 2-ethylhexyl acrylate is approximately -50°C. Both effectively reduce the Tg of the copolymer, ensuring sufficient freedom of movement of the chain segments at room temperature to promote hydrogen bond recombination. The Tg of the homopolymer of methyl methacrylate is approximately 105°C, providing the necessary hardness and abrasion resistance for the coating film. The acidic monomer is selected from at least one of acrylic acid (AA) and methacrylic acid (MAA), the hydroxyl monomer is selected from at least one of hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA), the amide monomer is selected from at least one of acrylamide (AAm), N-methacrylamide, and diethyl ketone acrylamide (DAAM), and the crosslinking monomer is ethylene glycol dimethacrylate (EGDMA).

[0012] Furthermore, based on a total comonomer content of 100 wt%, the acidic monomer content is 1%–4%, the hydroxyl monomer content is 2%–8%, the amide monomer content is 1%–6%, the crosslinking monomer content is 0.1%–0.8%, and the balance is soft and hard monomers, with a soft monomer to hard monomer mass ratio of 55:45–70:30. Maintaining the soft monomer to hard monomer mass ratio within the range of 55:45–70:30 allows the copolymer's Tg to be kept within a suitable window (approximately -5℃ to 15℃), ensuring sufficient segmental flexibility at room temperature for self-healing without excessively sacrificing coating hardness.

[0013] The modified zeolite molecular sieve is 13X zeolite molecular sieve, 5A zeolite molecular sieve, or a mixture thereof, with a particle size of 200-800 mesh. Its surface is simultaneously grafted with a first polar functional group introduced by a first silane modifier and a second hydrophobic organic segment introduced by a second silane modifier. This invention employs a dual-silane synergistic modification strategy. The design principle is as follows: the first silane modifier introduces polar functional groups (such as amino, epoxy, or methacryloyloxy groups) onto the surface of the zeolite molecular sieve. These polar groups can form intermolecular hydrogen bonds with hydroxyl and amide groups on the functionalized polyacrylic acid emulsion molecular chains, thereby establishing a reversible non-covalent bridge between the organic phase and the inorganic filler, significantly enhancing the interfacial bonding force. The second silane modifier introduces hydrophobic organic segments (such as octyl or dodecyl groups) onto the surface of the zeolite molecular sieve, reducing the surface energy of the zeolite molecular sieve and transforming the originally overly hydrophilic zeolite molecular sieve into a filler with moderate hydrophobicity, preventing it from becoming a channel for water penetration in the coating.

[0014] Further, the first silane modifier is selected from at least one of γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), and γ-methacryloyloxypropyltrimethoxysilane (KH570); the second silane modifier is selected from at least one of octyltriethoxysilane and dodecyltrimethoxysilane.

[0015] Furthermore, the mass ratio of the first silane modifier to the second silane modifier is 1:0.3 to 1.2, and the total grafting amount is 2% to 6% of the mass of the zeolite molecular sieve before modification.

[0016] Furthermore, the cement is ordinary Portland cement, sulfoaluminate cement, or a mixture thereof. Ordinary Portland cement provides basic cementitious strength; sulfoaluminate cement has a fast hydration rate, high early strength, and the ettringite produced during hydration has micro-expansion properties, which helps compensate for coating shrinkage and reduce early cracking.

[0017] This invention also provides a method for preparing the above-mentioned hydrogen bond self-healing organic-inorganic waterproof concrete coating, comprising the following steps: S1. Activate the zeolite molecular sieve at 250–300℃ for 1.5–3 hours to obtain activated zeolite molecular sieve. The purpose of high-temperature activation is to remove the moisture and organic impurities adsorbed in the pores of the zeolite molecular sieve, expose the active sites of silanol groups on the surface, and provide sufficient reaction sites for subsequent silane grafting.

[0018] S2. The activated zeolite molecular sieve is surface modified using an equal-volume impregnation method, which simultaneously grafts a first polar functional group and a second hydrophobic organic segment onto its surface to obtain a modified zeolite molecular sieve. The equal-volume impregnation method refers to using an impregnation solution whose volume is equal to or slightly less than the total pore volume of the zeolite molecular sieve. This ensures that the silane modifier solution is completely absorbed into the pores and surface of the zeolite molecular sieve by capillary action, avoiding uneven silane distribution and waste caused by excessive solvent.

[0019] Further, in step S2, the first and second silane modifiers are dissolved in an ethanol / water mixed solvent to prepare an impregnation solution. The volume ratio of ethanol to water is 80:20 to 95:5. The pH of the impregnation solution is adjusted to 3.5 to 5.0 using acetic acid or dilute hydrochloric acid, preferably acetic acid. The volume of the impregnation solution is 0.9 to 1.1 times the total pore volume of the activated zeolite molecular sieve. After impregnation for 1 to 3 hours, the solution is aged for 3 to 12 hours to allow silane molecules to fully diffuse to the surface and inner walls of the pores of the zeolite molecular sieve and complete the initial condensation. Then, the solution is dried at 80 to 120°C for 2 to 8 hours to remove the solvent, and then cured at 120 to 180°C for 1 to 4 hours to further promote the condensation reaction between the silane and the surface of the zeolite molecular sieve, forming a strong covalent grafted layer.

[0020] S3. At 20–30°C, mix water, dispersant, wetting agent, defoamer, thickener, and preservative, then add functionalized polyacrylic acid emulsion and film-forming aids. Disperse at 500–1200 r / min for 10–25 min to obtain liquid A. Dissolving or dispersing each aid in the aqueous phase before adding it to the emulsion avoids the risk of demulsification caused by the direct impact of high-concentration aids on the emulsion particles.

[0021] Further, the functionalized polyacrylic acid emulsion described in step S3 is prepared by the following method: a pre-emulsion is prepared by mixing soft monomers, hard monomers, acidic monomers, hydroxyl monomers, amide monomers, crosslinking monomers, emulsifiers, and water. The pre-emulsion is then added dropwise at 75–82°C for 2–4 hours in the presence of an initiator, followed by a 1–2 hour incubation. After the reaction is complete, the pH is adjusted to 7.5–8.5 to obtain a functionalized polyacrylic acid emulsion with a solid content of 40%–55%. The pre-emulsion dropwise addition process, rather than direct monomer addition, is used because the monomers enter the reaction system uniformly in the form of fine droplets after pre-emulsification. This facilitates uniform copolymerization of the monomers according to the designed proportions, reduces compositional drift, and makes the distribution of hydrogen bond donor and acceptor groups on the polymer chain more uniform, thereby improving the uniformity and self-healing efficiency of the hydrogen bond network.

[0022] Further, the emulsifier is selected from at least one of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether, and allyloxynonylphenol polyoxyethylene (10) ether ammonium sulfonate, and the amount used is 2% to 3.5% of the total comonomer. Sodium dodecyl sulfate is an anionic emulsifier with high emulsification efficiency; nonylphenol polyoxyethylene ether is a nonionic emulsifier with strong electrolyte resistance, suitable for use in conjunction with cement systems; allyloxynonylphenol polyoxyethylene (10) ether ammonium sulfonate is a reactive emulsifier. The initiator is selected from at least one of ammonium persulfate and potassium persulfate, and the amount used is 0.4% to 0.8% of the total comonomer.

[0023] S4. At 20-30℃, cement, modified zeolite molecular sieve, silica fume, quartz powder, quartz sand, heavy calcium carbonate, cellulose ether, water-reducing agent and defoamer are dry-mixed for 8-15 minutes to obtain powder B.

[0024] S5. At 20–30°C, the liquid A and powder B are mixed at a mass ratio of 0.9–1.1:1 and stirred at 400–700 r / min for 3–8 min to obtain a concrete coating. This stirring speed and time are sufficient to fully wet and disperse the powder while avoiding excessive shear that could lead to emulsion demulsification and the introduction of excessive air bubbles.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) By introducing three types of polar groups, namely hydroxyl, amide and ester carbonyl, into the molecular chain of polyacrylic acid copolymer, when microcracks are generated in the coating, the broken hydrogen bonds on the crack surface can spontaneously recombine under the drive of temperature or humidity, so that the polymer chain segments on both sides of the crack are rebridged, giving the coating intrinsic self-healing ability, extending the effective service life of the waterproof coating, and reducing the frequency and cost of maintenance.

[0026] (2) This invention employs a first silane modifier and a second silane modifier to synergistically modify the surface of zeolite molecular sieves, enabling the modified zeolite molecular sieves to possess both polar functional groups and hydrophobic organic segments. The polar functional groups form a reversible interfacial bridge with the polymer matrix through hydrogen bonds, enhancing the organic-inorganic interfacial bonding force; the hydrophobic organic segments reduce the surface energy of the zeolite molecular sieve, preventing the hydrophilic zeolite molecular sieve from becoming a water permeation channel. The dual-functional modification strategy solves the technical contradiction of difficulty in balancing hydrophobicity and interfacial compatibility in traditional single silane modification, and helps to improve the interfacial stability and waterproof durability of the coating film.

[0027] (3) The polar functional groups on the surface of the modified zeolite molecular sieve (such as amino groups, hydroxyl groups generated by epoxy ring opening, etc.) can also form hydrogen bond interactions across the organic-inorganic interface with the hydrogen bond groups on the polymer chain, so that the self-healing hydrogen bond network not only exists in the organic phase, but also extends to the organic-inorganic interface region, further enhancing the overall self-healing effect and interface durability of the coating.

[0028] (4) The coating of the present invention adopts a two-component form in which liquid and powder are packaged separately and mixed on site. The preparation process is simple, and each component is a conventional chemical raw material. The cost is controllable and it is convenient for engineering production and construction application. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise stated, all "parts" below refer to parts by weight, and all percentages below refer to the mass percentage of the total comonomer. The dispersant is a polyacrylate dispersant, the wetting agent is a polyether-modified trisiloxane wetting agent, the defoamer in liquid A is a mineral oil / organosilicon composite defoamer, the thickener is an associative polyurethane thickener, the preservative is an isothiazolinone preservative, and the film-forming aid is dodecyl alcohol ester; the cellulose ether is hydroxypropyl methylcellulose ether, the water-reducing agent is a polycarboxylate powder water-reducing agent, and the defoamer in powder B is a polyether-modified organosilicon powder defoamer. Example 1

[0031] Preparation of modified zeolite molecular sieves: 13X zeolite molecular sieves with a particle size of 400 mesh and 5A zeolite molecular sieves with a particle size of 400 mesh were mixed at a mass ratio of 1:1 and activated at 275℃ for 2 hours to obtain activated zeolite molecular sieves. Based on the mass of the unmodified zeolite molecular sieves, the total grafting amount was controlled at 4%. γ-aminopropyltriethoxysilane was selected as the first silane modifier, and octyltriethoxysilane was selected as the second silane modifier, with a mass ratio of 1:0.8. The two modifiers were dissolved in a mixed solvent of ethanol / water at a volume ratio of 90:10. The pH of the impregnation solution was adjusted to 4.2 using acetic acid, and the volume of the impregnation solution was 1.0 times the total pore volume of the activated zeolite molecular sieves. After impregnation for 2 hours, the mixture was aged for 6 hours, dried at 100℃ for 4 hours, and then cured at 150℃ for 2 hours to obtain the modified zeolite molecular sieves.

[0032] Preparation of functionalized polyacrylic acid emulsion: Based on a total comonomer content of 100 parts, 44 parts butyl acrylate, 11 parts 2-ethylhexyl acrylate, 33 parts methyl methacrylate, 3 parts acrylic acid, 5 parts hydroxyethyl methacrylate, 2 parts acrylamide, 1.5 parts diethyl ketone acrylamide, 0.5 parts ethylene glycol dimethacrylate, 1.5 parts sodium dodecyl sulfate, 1.0 part nonylphenol polyoxyethylene ether, and 65 parts deionized water were mixed to prepare a pre-emulsion. 25 parts deionized water were added to a reaction vessel, nitrogen was purged, and the temperature was raised to 78°C. An initiator solution prepared from 0.6 parts ammonium persulfate and 10 parts deionized water was added. The pre-emulsion was added dropwise at 78°C for 3 hours. After the addition was completed, the temperature was maintained for 1.5 hours. The pH was adjusted to 8.0 with ammonia water to obtain a functionalized polyacrylic acid emulsion with a solid content of 49%.

[0033] Preparation of liquid A: At 25°C, 13 parts water, 0.5 parts dispersant, 0.4 parts wetting agent, 0.3 parts defoamer, 0.6 parts thickener and 0.2 parts preservative were mixed evenly, and then 63 parts of the above-mentioned functionalized polyacrylic acid emulsion and 2 parts film-forming aid were added. The mixture was dispersed at 800 r / min for 18 min to obtain liquid A.

[0034] Preparation of powder B: At 25°C, ordinary silicate cement and sulfoaluminate cement were mixed at a ratio of 8:2 as cement components, with a total amount of 38 parts. Then, 10 parts of modified zeolite molecular sieve, 5 parts of silica fume, 13 parts of quartz powder, 23 parts of quartz sand, 14 parts of heavy calcium carbonate, 0.6 parts of cellulose ether, 0.6 parts of water-reducing agent, and 0.3 parts of defoamer were added and dry-mixed for 10 minutes to obtain powder B.

[0035] Preparation of coating: At 25℃, liquid A and powder B are mixed at a mass ratio of 1:1 and stirred at 500 r / min for 5 min to obtain a hydrogen bond self-healing organic-inorganic waterproof concrete coating. Examples 2 through 5 were all carried out according to the method of Example 1, with the differences shown in Tables 1 through 3.

[0036] Table 1. Formulation and mixing process of liquid material A and powder material B: ; .

[0037] Table 2. Composition and polymerization conditions of functionalized polyacrylic acid emulsions: ; .

[0038] Table 3. Preparation conditions of modified zeolite molecular sieves: . Comparative Example 1

[0039] Except for replacing the functionalized polyacrylic acid emulsion in Example 1 with a conventional polyacrylic acid emulsion, all other conditions were the same as in Example 1. The conventional polyacrylic acid emulsion, based on a total comonomer of 100 parts, was obtained by copolymerizing 48.3 parts of butyl acrylate, 12.1 parts of 2-ethylhexyl acrylate, 36.1 parts of methyl methacrylate, 3 parts of acrylic acid, and 0.5 parts of ethylene glycol dimethacrylate, and did not contain hydroxyl monomers or amide monomers. Comparative Example 2

[0040] Except for replacing the modified zeolite molecular sieve in Example 1 with an unmodified 13X / 5A mixed zeolite molecular sieve, all other conditions were the same as in Example 1. Comparative Example 3

[0041] Except for replacing the modified zeolite molecular sieve in Example 1 with a zeolite molecular sieve modified only by KH550, all other conditions are the same as in Example 1; the total grafting amount is still 4%. Comparative Example 4

[0042] Except for replacing the modified zeolite molecular sieve in Example 1 with a zeolite molecular sieve modified only with octyltriethoxysilane, all other conditions are the same as in Example 1; the total grafting amount is still 4%. Test methods

[0043] The sample preparation method is as follows: The coatings obtained from each embodiment and comparative example were respectively made into free film samples and mortar board coated samples. The free film samples were coated on a polytetrafluoroethylene release liner, and the dry film thickness was controlled at 1.5±0.1 mm. They were cured for 7 days at 23±2℃ and 50±5% relative humidity. The mortar board coated samples used cement mortar board as the substrate, and the coating conditions were the same as the curing conditions.

[0044] Standard performance testing methods: Tensile strength, elongation at break, and impermeability were tested according to GB / T 16777-2008; 24-hour water absorption was tested according to JC / T 2663-2022; the water contact angle was measured on the free membrane surface using a contact angle meter, referring to GB / T 30693-2014; and the pull-off adhesion to the mortar substrate was tested according to GB / T 5210-2006. All data were taken as the average of three parallel samples.

[0045] Self-healing performance uses the following custom method: (1) Scratch closure rate: A linear scratch with a width of 0.20±0.02mm and a depth of about 1 / 2 of the film thickness was prepared on the surface of the free membrane using a knife, and the initial scratch width w0 was recorded; after the sample was placed in an environment of 40℃ and 95% relative humidity for 24h, the scratch width wt after healing was measured; scratch closure rate = (w0-wt) / w0×100%.

[0046] (2) Tensile strength recovery rate: The dumbbell-shaped free membrane specimen was cut in the middle of the gauge length so that the two sections were in close contact again. After being placed in an environment of 40℃ and 95% relative humidity for 24 hours, the tensile strength was tested. Tensile strength recovery rate = tensile strength after repair / original tensile strength × 100%.

[0047] (3) Impermeability recovery rate: A through scratch with a width of 0.20±0.02mm and a length of 20mm was prepared on the surface of the mortar board coating. The maximum impermeability pressure P0 of the original sample, the impermeability pressure Ps after scratching, and the impermeability pressure Ph after healing for 24 hours were recorded respectively. Impermeability recovery rate = (Ph-Ps) / (P0-Ps)×100%.

[0048] Table 4. Results of routine performance tests: .

[0049] Table 5. Self-healing performance test results: .

[0050] Results Analysis As can be seen from Tables 4 and 5, the coatings prepared in each embodiment all possess good mechanical properties, waterproof properties, and self-healing capabilities, verifying the feasibility of the technical solution of the present invention within the scope of the claims.

[0051] Example 1 showed the best overall performance across all indicators, with tensile strength of 2.56 MPa, elongation at break of 188%, pull-out adhesion of 1.62 MPa, water contact angle of 107.8°, and 24-hour water absorption of 3.1%. Scratch closure rate, tensile strength recovery rate, and impermeability recovery rate reached 90%, 91%, and 95%, respectively, indicating that the combination of formulation parameters within the median range had a good synergistic matching effect. Example 2 had the lower limit levels of functional monomer dosage and zeolite molecular sieve grafting, resulting in relatively low hydrogen bond network density and interface control, and a slight decrease in self-healing efficiency and adhesion. However, all performance indicators remained at a reasonable level, proving that the lower limit parameter range could also achieve the purpose of this invention. Example 3 had a higher proportion of inorganic fillers, leading to a slight increase in coating water absorption. Its overall performance was lower than Example 1, indicating that there is a reasonable upper limit to the introduction of functional groups and modified fillers, and more is not necessarily better. Examples 4 and 5, using different combinations of silane coupling agents, zeolite molecular sieve types, and cement compounding methods, all achieved the requirement of 0.3 MPa impermeability, demonstrating that the present invention has good applicability under various raw material combinations.

[0052] The comparative results further illustrate the necessity of each technical element. In Comparative Example 1, after removing the hydroxyl and amide monomers, the three self-healing indicators decreased significantly (scratch closure rate was only 31%), indicating that the multiple hydrogen bonds on the polymer chain are an important source of the coating's self-healing ability. Comparative Example 2, using unmodified zeolite molecular sieves, showed a water absorption rate of 6.7% after 24 hours and leakage occurred at 0.2 MPa, indicating that surface modification of the zeolite molecular sieve is indispensable. Comparative Example 3, using only polar silane modification, achieved a pull-out adhesion of 1.23 MPa, higher than the unmodified zeolite molecular sieve system, but a 24-hour water absorption rate of only 5.3% and a water contact angle of only 92.1°, indicating that while polar modification helps with interfacial bonding, its hydrophobic and water-blocking capabilities are insufficient. Comparative Example 4 only used hydrophobic silane modification, which increased the water contact angle to 106.5° and reduced the water absorption rate to 3.8% after 24 hours, showing good surface hydrophobicity. However, its pull-off adhesion was only 1.19 MPa, and its self-healing related indicators were still significantly lower than those of the example, indicating that single hydrophobic modification is difficult to balance interfacial bonding and self-healing performance.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydrogen-bonded self-healing organic-inorganic waterproof concrete coating, characterized in that, The coating is composed of liquid component A and powder component B mixed at a mass ratio of (0.9-1.1):1; The liquid component A comprises, by weight, 55-70 parts of functionalized polyacrylic acid emulsion, 8-18 parts of water, 1-3 parts of film-forming aid, 0.2-0.8 parts of dispersant, 0.1-0.6 parts of wetting agent, 0.1-0.5 parts of defoamer, 0.2-1.0 parts of thickener, and 0.1-0.3 parts of preservative; The powder B, by weight, comprises: 30-45 parts cement, 5-15 parts modified zeolite molecular sieve, 2-8 parts silica fume, 8-18 parts quartz powder, 15-30 parts quartz sand, 8-20 parts heavy calcium carbonate, 0.2-1.0 parts cellulose ether, 0.2-1.0 parts water-reducing agent, and 0.1-0.5 parts defoamer; The functionalized polyacrylic acid emulsion is obtained by copolymerization of soft monomers, hard monomers, acidic monomers, hydroxyl monomers, amide monomers and crosslinking monomers, and the resulting polymer chain contains hydroxyl, amide and ester carbonyl groups; The modified zeolite molecular sieve is 13X zeolite molecular sieve, 5A zeolite molecular sieve or a mixture thereof, with a particle size of 200-800 mesh, and its surface is simultaneously grafted with a first polar functional group introduced by a first silane modifier and a second hydrophobic organic segment introduced by a second silane modifier.

2. The hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to claim 1, characterized in that, The soft monomer is selected from at least one of butyl acrylate and 2-ethylhexyl acrylate, the hard monomer is methyl methacrylate, the acidic monomer is selected from at least one of acrylic acid and methacrylic acid, the hydroxyl monomer is selected from at least one of hydroxyethyl methacrylate and hydroxypropyl methacrylate, the amide monomer is selected from at least one of acrylamide, N-methacrylamide and diethyl ketone acrylamide, and the crosslinking monomer is ethylene glycol dimethacrylate.

3. The hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to claim 2, characterized in that, Based on a total comonomer content of 100 wt%, the acidic monomer content is 1% to 4%, the hydroxyl monomer content is 2% to 8%, the amide monomer content is 1% to 6%, the crosslinking monomer content is 0.1% to 0.8%, and the balance is soft monomers and hard monomers, with a mass ratio of soft monomers to hard monomers of 55:45 to 70:

30.

4. The hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to claim 1, characterized in that, The first silane modifier is selected from at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; The second silane modifier is selected from at least one of octyltriethoxysilane and dodecyltrimethoxysilane.

5. The hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to claim 4, characterized in that, The mass ratio of the first silane modifier to the second silane modifier is 1:0.3 to 1.2, and the total grafting amount is 2% to 6% of the mass of the zeolite molecular sieve before modification.

6. The hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to claim 1, characterized in that, The cement is ordinary silicate cement, sulfoaluminate cement, or a mixture thereof.

7. A method for preparing a hydrogen-bonded self-healing organic-inorganic waterproof concrete coating according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Activate the zeolite molecular sieve at 250-300℃ for 1.5-3 hours to obtain activated zeolite molecular sieve; S2. The activated zeolite molecular sieve is surface modified by an equal-volume impregnation method, so that the surface is simultaneously grafted with a first polar functional group and a second hydrophobic organic segment to obtain a modified zeolite molecular sieve. S3. At 20-30℃, water, dispersant, wetting agent, defoamer, thickener and preservative are mixed, and functionalized polyacrylic acid emulsion and film-forming aid are added. The mixture is dispersed at 500-1200 r / min for 10-25 min to obtain liquid A. S4. At 20-30℃, cement, modified zeolite molecular sieve, silica fume, quartz powder, quartz sand, heavy calcium carbonate, cellulose ether, water-reducing agent and defoamer are dry mixed for 8-15 minutes to obtain powder B. S5. At 20-30℃, the liquid material A and powder material B are mixed in a mass ratio and stirred at 400-700 r / min for 3-8 min to obtain concrete coating.

8. The preparation method according to claim 7, characterized in that, When using the equal-volume impregnation method in step S2, the first silane modifier and the second silane modifier are dissolved in an ethanol / water mixed solvent to prepare an impregnation solution. The volume ratio of ethanol to water is 80:20 to 95:

5. The pH of the impregnation solution is adjusted to 3.5 to 5.0 using acetic acid or dilute hydrochloric acid. The volume of the impregnation solution is 0.9 to 1.1 times the total pore volume of the activated zeolite molecular sieve. After impregnation for 1 to 3 hours, the solution is aged for 3 to 12 hours, dried at 80 to 120°C for 2 to 8 hours, and then cured at 120 to 180°C for 1 to 4 hours.

9. The preparation method according to claim 7, characterized in that, The functionalized polyacrylic acid emulsion described in step S3 is prepared by the following method: a pre-emulsion is prepared by mixing soft monomers, hard monomers, acidic monomers, hydroxyl monomers, amide monomers, crosslinking monomers, emulsifiers and water. The pre-emulsion is then added dropwise at 75-82°C for 2-4 hours in the presence of an initiator and kept at this temperature for 1-2 hours. After the reaction is completed, the pH is adjusted to 7.5-8.5 to obtain a functionalized polyacrylic acid emulsion with a solid content of 40%-55%.

10. The preparation method according to claim 9, characterized in that, The emulsifier is selected from at least one of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether and allyloxynonylphenol polyoxyethylene (10) ether ammonium sulfonate, and the amount used is 2% to 3.5% of the total amount of comonomer; the initiator is selected from at least one of ammonium persulfate and potassium persulfate, and the amount used is 0.4% to 0.8% of the total amount of comonomer.