Invisible waterproof agent based on double-lock sustained-release microspheres and preparation method of invisible waterproof agent

Abstract

The invention discloses an invisible waterproof agent based on double-lock sustained release microspheres and a preparation method of the invisible waterproof agent. The invisible waterproof agent is composed of a super-crosslinked polymer composite system and a water-based main system, wherein the super-crosslinked polymer composite system is formed by carrying out in-situ polymerization reaction on the following raw materials: phenyl modified siloxane, a polymeric monomer, a catalyst, a silane coupling agent and graphene quantum dots. The graphene quantum dots are introduced into the in-situ polymerization super-crosslinked polymer carrier, a'covalent anchoring-pi stacking 'dual composite action mechanism is constructed, and fine regulation and control of hydrophobic agent release kinetics are achieved. A double-lock cooperative intelligent release mechanism is formed, so that the release of the hydrophobing agent is converted into stress triggering-grading response from traditional pore channel diffusion, the response to coating damage is more direct, repairing is faster, and the service life is longer. High loading capacity and firm wrapping of the hydrophobic agent are achieved, and the problems that a traditional two-step method is complex in process, not firm in loading and prone to leakage are solved.

Description

Technical Field

[0001] This invention belongs to the field of building chemical protective materials technology, and relates to an invisible waterproofing agent based on "double-locking" slow-release microspheres and its preparation method. Specifically, it is an intelligent slow-release invisible waterproofing agent for building exterior walls and its preparation method. This waterproofing agent utilizes an innovative in-situ polymerization nanocomposite process to directly encapsulate hydrophobic functional components within a hypercrosslinked polymer network, and introduces graphene quantum dots as regulatory units, exhibiting characteristics such as long-lasting self-healing, high transparency, superhydrophobicity, and high durability. Background Technology

[0002] Building exterior walls are constantly exposed to complex natural environments such as rainwater, ultraviolet radiation, pollutants, and freeze-thaw cycles, making them prone to problems such as water seepage, micro-cracks, weathering, dirt accumulation, and performance degradation. Traditional waterproofing materials, such as silicone and acrylic resins, while offering some protection, generally suffer from limitations in functionality and durability, especially lacking the ability to actively repair themselves after damage, resulting in a limited protective lifespan.

[0003] To improve durability, existing technologies have introduced the concept of intelligent slow release, which involves pre-loading hydrophobic agents onto a porous carrier and then incorporating them into a coating to achieve self-repair after damage. Using inorganic mesoporous materials (such as silica) as the carrier is the mainstream technical approach. However, this type of inorganic carrier-based approach has several inherent drawbacks: First, the surface of inorganic carriers is usually hydrophilic, requiring complex chemical modifications (such as amination) to effectively adsorb hydrophobic agents, which is cumbersome and increases costs; second, inorganic nanoparticles have poor compatibility with organic resin matrices, easily affecting the transparency and stability of the coating; finally, the release mechanism is mostly simple diffusion after physical adsorption, and the release behavior is not "intelligent" enough to achieve a precise response to external damage or environmental changes.

[0004] Furthermore, this type of "two-step" process (first synthesizing the carrier, then impregnating and loading) has inherent limitations: the loading process depends on the inherent pore size and surface chemistry of the carrier, resulting in limited hydrophobic agent loading and weak bonding, making it prone to leakage during storage or early use, leading to a decline in long-term repair capabilities. Therefore, developing a novel carrier that can achieve efficient loading, strong bonding, and intelligent response, along with a simplified process to match, is crucial for promoting the practical application of intelligent self-healing waterproof coatings.

[0005] Hypercrosslinked polymers are a class of high-specific-surface-area organic porous materials formed from aromatic monomers through Friedel-Crafts reactions, etc. Their framework is intrinsically hydrophobic, exhibiting excellent compatibility with organic hydrophobic agents. If the loading of the hydrophobic agent and the formation of the polymer network can be completed in a single step, it is hoped that the aforementioned technical bottlenecks can be fundamentally overcome. However, how to combine this material characteristic with innovative waterproofing agent preparation processes, especially how to further finely control the release kinetics of the hydrophobic agent (such as release rate, response sensitivity, and repair durability) while ensuring high coating transparency, so as to better match it with the complex damage modes of the coating in actual use, remains a key technical challenge that urgently needs to be overcome in this field. Existing technologies lack effective means for "micro-tuning" the release interface at the nanoscale, which limits the further improvement of the performance and practical application of intelligent self-healing coatings. Summary of the Invention

[0006] The primary objective of this invention is to provide an invisible waterproofing agent based on "dual-lock" sustained-release microspheres and its preparation method. Specifically, it is a smart sustained-release invisible waterproofing agent based on an in-situ polymerized hypercrosslinked polymer, possessing high transparency, excellent waterproofing, superior abrasion resistance, and long-lasting self-healing function. This invention achieves precise control of the hydrophobic agent release kinetics by introducing graphene quantum dots into the in-situ polymerized hypercrosslinked polymer carrier, constructing a dual composite mechanism of "covalent anchoring-π stacking."

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The present invention provides a smart slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer, which is composed of a hypercrosslinked polymer composite system and a water-based main system.

[0009] The aforementioned hypercrosslinked polymer composite system is formed by in-situ polymerization of the following raw materials in parts by mass: 2.0-4.0 parts of phenyl-modified siloxane, 3.0-6.0 parts of polymeric monomer, 0.1-0.4 parts of catalyst, 1.0-2.0 parts of silane coupling agent, and 0.001-0.05 parts of graphene quantum dots.

[0010] The water-based main system components are in the following mass proportions: 75-82 parts silicone-acrylic emulsion, 1.0-1.5 parts polyurethane hardener, 2.0-3.0 parts film-forming aid, 0.5-1.0 parts wetting and dispersing agent, 0.3-0.6 parts defoamer, 0.2-0.5 parts thickener, and 8-12 parts deionized water.

[0011] In this invention, the phenyl-modified siloxane is at least one of phenyl hydrogen-containing silicone oil or hydroxyl-terminated phenyl silicone oil, with a phenyl content of 20%–40% and a viscosity of 300–800 mPa·s. In the system, it serves both as a coated hydrophobic repair agent and as an organic phase medium for the polymerization reaction; its phenyl structure can generate π-π stacking interactions with graphene quantum dots.

[0012] In this invention, the polymerizing monomer comprises a crosslinking monomer and a comonomer. The crosslinking monomer is divinylbenzene, used in an amount of 1.5–3.0 parts; the comonomer is benzene or toluene, used in an amount of 1.5–3.0 parts. Both undergo Friedel-Crafts alkylation under the action of a catalyst to form a three-dimensional hypercrosslinked polymer network. The preferred ratio of the crosslinking monomer to the comonomer is 1:1.

[0013] In this invention, the graphene quantum dots are nanoparticles with a surface rich in carboxyl or hydroxyl groups and a size of less than 10 nm. The preferred addition amount is 0.001% to 0.05% of the total mass of the waterproofing agent. In the system, they can combine with the aromatic structure of phenyl-modified siloxane and the hypercrosslinked polymer network through π-π stacking interactions to form a reversible "secondary dynamic lock," thereby finely controlling the release behavior of the hydrophobic agent. Simultaneously, their nanoscale size and low addition amount ensure high transparency of the coating.

[0014] In this invention, the catalyst is a Lewis acid catalyst, preferably anhydrous aluminum trichloride or anhydrous ferric trichloride, and the amount used is 0.1 to 0.4 parts.

[0015] In this invention, the silane coupling agent is a diamino silane, preferably N-β-aminoethyl-γ-aminopropyltrimethoxysilane, with an amino content ≥95% and a purity ≥98%. It is used to surface-functionalize the hydrophobic microspheres obtained from polymerization to connect to an aqueous system.

[0016] In this invention, the solid content of the silicone-acrylic emulsion is 40% to 50%, and the glass transition temperature is 10 to 20°C.

[0017] In this invention, the film-forming aid is 12-ol ester.

[0018] In this invention, the thickener is a hydrophobically modified alkali-swellable thickener with a solid content of 28% to 32%.

[0019] Another objective of this invention is to provide a method for preparing the aforementioned waterproofing agent. This method, through an innovative in-situ polymerization loading and nanocomposite process, completes the preparation and compounding of functional components in one step. The process is simplified, stable, and more suitable for large-scale production. The specific steps are as follows:

[0020] Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres

[0021] In a dry reactor, phenyl-modified siloxane, divinylbenzene, and benzene were mixed in proportion and stirred at room temperature to form a homogeneous oil phase. The system was cooled to 0–5°C, and anhydrous aluminum trichloride catalyst was rapidly added with stirring. After maintaining the low temperature for 1–2 hours, the temperature was raised to 40–60°C, and the reaction was continued for 6–12 hours. After the reaction was completed, the mixture was quenched, filtered, and washed to obtain a wet supercrosslinked polymer loaded with a hydrophobic agent.

[0022] Step 2: Microsphere surface functionalization

[0023] The wet material obtained in step 1 was dispersed in ethanol, and silane coupling agent KH792 was added. The mixture was refluxed at 60–70 °C for 4–6 hours. After the reaction was completed, the mixture was separated, washed, and dried to obtain functionalized hypercrosslinked polymer sustained-release microspheres with amino groups on the surface.

[0024] Step 3: Preparation of composite masterbatch

[0025] The functionalized slow-release microspheres obtained in step 2 are mixed with an appropriate amount of deionized water, and the formulated amount of graphene quantum dots are added. The mixture is ultrasonically dispersed at 300W power for 20-30 minutes to allow the graphene quantum dots to be fully adsorbed and dispersed on the surface and gaps of the slow-release microspheres, forming a uniform composite masterbatch dispersion.

[0026] Step 4: Compounding with the water-based main system

[0027] Place the silicone-acrylic emulsion in a reactor and slowly add the composite masterbatch dispersion obtained in step 3 into the emulsion while stirring at a low speed of 400-600 rpm, controlling the feeding time to 10-15 minutes.

[0028] Step 5: Addition and homogenization of additives

[0029] Add the film-forming aid, wetting and dispersing agent and defoamer in sequence while stirring continuously. After the addition is complete, increase the stirring speed to 800-1000 rpm and continue stirring for 20-30 minutes.

[0030] Step 6: Strengthening and Setting Adhesion

[0031] Maintain a stirring speed of 800–1000 rpm, add the polyurethane hardener, and continue stirring for 15–25 minutes to ensure uniform mixing. Predissolve the thickener in the remaining deionized water and add it to the system, then reduce the stirring speed to 200–300 rpm and continue stirring for 30–40 minutes.

[0032] Step 7: Maturation and Finished Product

[0033] The obtained product was allowed to stand and mature at room temperature for 3–5 hours, and then filtered through a 5–10 μm precision filter to obtain a finished product of a smart slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer.

[0034] In step 1 of this invention, the in-situ polymerization reaction conditions are: a low-temperature stage of 0-5°C for 1-2 hours, and a heating stage of 40-60°C for 6-12 hours.

[0035] In step 2 of this invention, the surface functionalization conditions are: reflux reaction at 60-70°C for 4-6 hours in ethanol solvent.

[0036] In step 7 of this invention, the curing environment temperature is 20-30°C and the relative humidity is 40%-60%.

[0037] This invention proposes a smart, slow-release, invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymers, exhibiting excellent waterproofing performance, abrasion resistance, self-healing function, and invisibility. After application, the waterproofing agent forms a colorless and transparent coating on the substrate surface, penetrating concrete substrates to a depth of 2-5 mm, with a water contact angle ≥150°, a roll-off angle ≤10°, and a weight loss of ≤0.015 g (750g / 500r). It also demonstrates excellent adhesion to various building materials such as concrete, stone, and bricks. In particular, after incorporating graphene quantum dots for regulation, the coating exhibits a significantly increased number of effective repair cycles (restoring more than 90% of its initial hydrophobicity) in multiple damage-repair cycle tests, demonstrating a longer self-healing lifespan.

[0038] Through experimentation, the inventors discovered that an in-situ polymerization process allows the hydrophobic agent, phenyl-modified siloxane, to be directly captured and encapsulated during the formation of a hypercrosslinked polymer network, creating a unique "island structure." Furthermore, the graphene quantum dots introduced into the system, with their abundant sp² carbon domains, generate strong π-π stacking interactions with the phenyl-modified siloxane and the aromatic structure of the polymer network, forming a dynamic "secondary weak bond network" within and on the surface of the original "island structure." This dual mechanism of "covalent anchoring primary lock" and "π-stacking dynamic secondary lock" ensures an extremely strong bond between the hydrophobic agent and the polymer matrix, overcoming the shortcomings of traditional impregnation methods, such as weak loading and easy initial leakage. When the coating is damaged, stress first triggers the relaxation of the polymer network primary lock, while the dynamic secondary lock formed by graphene quantum dots can subsequently undergo reversible slippage or dissociation. This not only ensures the timely release of the hydrophobic agent but also allows for precise control of its release rate and total amount, thereby achieving precise management of the repair behavior and effective extension of the repair life.

[0039] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0040] (1) By using the one-step in-situ polymerization process, the carrier synthesis and hydrophobic agent loading are combined into one, which significantly simplifies the process and achieves high loading and firm encapsulation of hydrophobic agent, solving the problems of complex traditional two-step process, weak load and easy leakage.

[0041] (2) As an organic carrier, the hypercrosslinked polymer has excellent intrinsic hydrophobicity and compatibility with organic hydrophobic agents and resin matrix, avoiding the problems of poor compatibility and easy impact on transparency caused by the introduction of inorganic nanoparticles, thus better ensuring the "invisibility" effect of the coating.

[0042] (3) By creatively introducing graphene quantum dots to construct “π-π stacked dynamic secondary locks” with aromatic components in the system, and cooperating with the “covalent anchoring main locks” of the hypercrosslinked network, the nanoscale fine control of the hydrophobic agent release dynamics is realized, making the self-healing behavior of the coating more predictable and durable.

[0043] (4) The "dual-lock synergy" intelligent release mechanism makes the release of hydrophobic agent change from the traditional "pore diffusion" to "stress triggering-graded response", which makes the response to coating damage more direct, the repair faster and the life longer.

[0044] (5) Through the bridging of silane coupling agent, a stable connection is built between functional microspheres, resin matrix and building substrate, and the adhesion and durability are further enhanced.

[0045] (6) The product integrates high efficiency, intelligent slow release, long-term self-healing, superhydrophobicity and high transparency, providing long-term, active and reliable protection for building exterior walls without changing their appearance. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the film formation, structure, and self-healing mechanism of the intelligent slow-release invisible waterproofing agent of the present invention. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0048] Example 1: This example uses an optimized monomer ratio (divinylbenzene:benzene = 1:1) and does not add graphene quantum dots as a benchmark for evaluating the effect of the core process.

[0049] The formulation of the intelligent slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer of the present invention is as follows:

[0050] The formulation of the hypercrosslinked polymer composite system is as follows: 3.0 parts of phenyl-modified siloxane, 2.0 parts of divinylbenzene, 2.0 parts of benzene, 0.2 parts of anhydrous aluminum trichloride, and 1.5 parts of KH792.

[0051] Water-based main system formulation: 78 parts silicone-acrylic emulsion, 1.2 parts polyurethane hardener, 2.5 parts film-forming aid, 0.8 parts wetting and dispersing agent, 0.4 parts defoamer, 0.3 parts thickener, and 10 parts deionized water.

[0052] The preparation method of the intelligent invisible waterproofing agent of the present invention:

[0053] Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres

[0054] In a dry 50 L jacketed glass reactor with variable frequency speed control, 3.0 kg of phenyl-modified siloxane, 2.0 kg of divinylbenzene, and 2.0 kg of benzene were first added. A frame-type stirrer was installed, and stirring was started at 400 rpm at room temperature for 30 minutes to form a homogeneous and transparent organic mixture. Ice-salt water was circulated through the reactor jacket to cool the system and maintain it at 0–5 °C. Under continuous stirring and low temperature, 0.2 kg of powdered anhydrous aluminum trichloride catalyst was rapidly added. This low-temperature reaction was maintained for 1.5 hours. Subsequently, the ice-salt water was removed, and the system was allowed to naturally heat to 50 °C, and the reaction was continued at this temperature for 8 hours to carry out the Friedel-Crafts alkylation hypercrosslinking polymerization reaction. After the reaction was completed, the reaction mixture was slowly poured into ice water containing dilute hydrochloric acid for quenching, and the solid product was obtained by filtration. The product was repeatedly washed with deionized water and ethanol until neutral to obtain a wet hypercrosslinked polymer supported on phenyl-modified siloxane.

[0055] Step 2: Microsphere surface functionalization

[0056] All the wet material obtained in step 1 was redispersed in 20 kg of ethanol and transferred to a 50 L reactor. 1.5 kg of KH792 silane coupling agent was added, a reflux condenser was installed, and the mixture was refluxed and stirred at 65 °C for 5 hours. After the reaction was completed, the mixture was cooled, filtered, and the solid product was washed twice with ethanol. Then, it was dried in a vacuum oven at 60 °C for 6 hours to obtain surface-amino-functionalized hypercrosslinked polymer sustained-release microsphere powder.

[0057] Step 3: Preparation of functional composite masterbatch

[0058] In a 30 L high-speed dispersion tank, 6.6 kg of deionized water was added, and a high-speed dispersion disc was installed. While stirring, all the functionalized slow-release microsphere powder obtained in step 2 was slowly added. The dispersion disc was rotated at 2000 rpm, and the ultrasonic probe was simultaneously turned on. The mixture was ultrasonically dispersed at 300 W for 30 minutes to form a uniform and stable functionalized composite masterbatch dispersion.

[0059] Step 4: Mixing the main emulsion

[0060] In a clean 100 L low-speed stirred tank, 78 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 500 rpm. The functional composite masterbatch dispersion obtained in step 3 was slowly and evenly added to the emulsion over 12 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0061] Step 5: Addition and blending of additives

[0062] While continuously stirring at 500 rpm, accurately add 2.5 kg of film-forming aid, 0.8 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 15 minutes. After the addition is complete, increase the stirring speed to 900 rpm and continue stirring for 25 minutes to ensure the system is thoroughly mixed.

[0063] Step 6: Compounding of hardening agents

[0064] While maintaining a stirring speed of 900 rpm, accurately add 1.2 kg of polyurethane hardener. After the addition is complete, continue stirring at this speed for 20 minutes to ensure that the polyurethane hardener is evenly distributed in the complex multiphase system.

[0065] Step 7: Adjusting viscosity and setting volume

[0066] Dissolve 0.3 kg of thickener in 3.3 kg of deionized water in a mixing tank and stir at 800 rpm for 10 minutes using a high-speed disperser to form a homogeneous slurry. Slowly add the thickener slurry to the main mixing vessel at 500 rpm. Then, rinse the mixing container with the remaining 3.4 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes to fully homogenize the system and achieve the required application viscosity.

[0067] Step 8: Maturation and Filtration

[0068] The product obtained in step 7 is pumped into a sealed curing tank and allowed to cure for 4 hours in a clean environment at 25°C and 50% relative humidity, allowing the bubbles to escape fully and the components to interact fully and reach equilibrium. Finally, the cured product is filtered through a 5μm precision filter and bottled to obtain the semi-transparent, milky-white intelligent invisible waterproofing agent.

[0069] Example 2: In this example, the ratio of crosslinking monomer to comonomer was adjusted to 2:1, while the remaining components and amounts remained the same as in Example 1, to investigate the effect of monomer ratio on microsphere structure and final coating performance.

[0070] The formulation of the intelligent slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer of the present invention is as follows:

[0071] The formulation of the hypercrosslinked polymer composite system is as follows: 3.0 parts of phenyl-modified siloxane, 2.5 parts of divinylbenzene, 1.25 parts of benzene, 0.2 parts of anhydrous aluminum trichloride, and 1.5 parts of KH792.

[0072] Water-based main system formulation: 78 parts silicone-acrylic emulsion, 1.2 parts polyurethane hardener, 2.5 parts film-forming aid, 0.8 parts wetting and dispersing agent, 0.4 parts defoamer, 0.3 parts thickener, and 10 parts deionized water.

[0073] The preparation method of the intelligent invisible waterproofing agent of the present invention:

[0074] Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres

[0075] In a dry 50 L jacketed glass reactor, 3.0 kg of phenyl-modified siloxane, 2.5 kg of divinylbenzene, and 1.25 kg of benzene were added. A frame-type stirrer was installed, and stirring was started at 400 rpm at room temperature for 30 minutes to form a homogeneous and transparent organic mixture. Ice-salt water was circulated through the reactor jacket to cool the system and maintain it at 0–5 °C. Under continuous stirring and low temperature, 0.2 kg of powdered anhydrous aluminum trichloride catalyst was rapidly added. This low-temperature reaction was maintained for 1.5 hours. Subsequently, the ice-salt water was removed, and the system was allowed to naturally heat to 50 °C, where the reaction continued for 8 hours. After the reaction was complete, the reaction mixture was slowly poured into ice water containing dilute hydrochloric acid for quenching, and the solid product was obtained by filtration. The product was repeatedly washed with deionized water and ethanol until neutral to obtain a wet supercrosslinked polymer supported on phenyl-modified siloxane.

[0076] Step 2: Microsphere surface functionalization

[0077] All the wet material obtained in step 1 was redispersed in 20 kg of ethanol and transferred to a 50 L reactor. 1.5 kg of KH792 silane coupling agent was added, a reflux condenser was installed, and the mixture was refluxed and stirred at 65 °C for 5 hours. After the reaction was completed, the mixture was cooled, filtered, and the solid product was washed twice with ethanol. Then, it was dried in a vacuum oven at 60 °C for 6 hours to obtain surface-amino-functionalized hypercrosslinked polymer sustained-release microsphere powder.

[0078] Step 3: Preparation of functional composite masterbatch

[0079] In a 30 L high-speed dispersion tank, 6.6 kg of deionized water was added, and a high-speed dispersion disc was installed. While stirring, all the functionalized slow-release microsphere powder obtained in step 2 was slowly added. The dispersion disc was rotated at 2000 rpm, and the ultrasonic probe was simultaneously turned on. The mixture was ultrasonically dispersed at 300 W for 30 minutes to form a uniform and stable functionalized composite masterbatch dispersion.

[0080] Step 4: Mixing the main emulsion

[0081] In a clean 100 L low-speed stirred tank, 78 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 500 rpm. The functional composite masterbatch dispersion obtained in step 3 was slowly and evenly added to the emulsion over 12 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0082] Step 5: Addition and blending of additives

[0083] While continuously stirring at 500 rpm, accurately add 2.5 kg of film-forming aid, 0.8 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 15 minutes. After the addition is complete, increase the stirring speed to 900 rpm and continue stirring for 25 minutes to ensure the system is thoroughly mixed.

[0084] Step 6: Compounding of hardening agents

[0085] While maintaining a stirring speed of 900 rpm, accurately add 1.2 kg of polyurethane hardener. After the addition is complete, continue stirring at this speed for 20 minutes to ensure that the polyurethane hardener is evenly distributed in the complex multiphase system.

[0086] Step 7: Adjusting viscosity and setting volume

[0087] Dissolve 0.3 kg of thickener in 3.3 kg of deionized water in a mixing tank and stir at 800 rpm for 10 minutes using a high-speed disperser to form a homogeneous slurry. Slowly add the thickener slurry to the main mixing vessel at 500 rpm. Then, rinse the mixing container with the remaining 3.4 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes to fully homogenize the system and achieve the required application viscosity.

[0088] Step 8: Maturation and Filtration

[0089] The product obtained in step 7 is pumped into a sealed curing tank and allowed to cure for 4 hours in a clean environment at 25°C and 50% relative humidity, allowing the bubbles to escape fully and the components to interact fully and reach equilibrium. Finally, the cured product is filtered through a 5μm precision filter and bottled to obtain the semi-transparent, milky-white intelligent invisible waterproofing agent.

[0090] Example 3: This example is based on the formulation of Example 1 (preferably with a monomer ratio of 1:1), with the addition of graphene quantum dots, in order to verify their synergistic enhancement effect on self-healing performance in the preferred system.

[0091] The formulation of the intelligent slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer of the present invention is as follows:

[0092] The formulation of the hypercrosslinked polymer composite system is as follows: 3.0 parts of phenyl-modified siloxane, 2.0 parts of divinylbenzene, 2.0 parts of benzene, 0.2 parts of anhydrous aluminum trichloride, 1.5 parts of KH792, and 0.02 parts of graphene quantum dots.

[0093] Water-based main system formulation: 78 parts silicone-acrylic emulsion, 1.2 parts polyurethane hardener, 2.5 parts film-forming aid, 0.8 parts wetting and dispersing agent, 0.4 parts defoamer, 0.3 parts thickener, and 10 parts deionized water.

[0094] The preparation method of the intelligent invisible waterproofing agent of the present invention:

[0095] Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres

[0096] In a dry 50 L jacketed glass reactor, 3.0 kg of phenyl-modified siloxane, 2.0 kg of divinylbenzene, and 2.0 kg of benzene were added. A frame-type stirrer was installed, and stirring was started at 400 rpm at room temperature for 30 minutes to form a homogeneous and transparent organic mixture. Ice-salt water was circulated through the reactor jacket to cool the system and maintain it at 0–5 °C. Under continuous stirring and low temperature, 0.2 kg of powdered anhydrous aluminum trichloride catalyst was rapidly added. This low-temperature reaction was maintained for 1.5 hours. Subsequently, the ice-salt water was removed, and the system was allowed to naturally heat to 50 °C, where the reaction continued for 8 hours. After the reaction was complete, the reaction mixture was slowly poured into ice water containing dilute hydrochloric acid for quenching, and the solid product was obtained by filtration. The product was repeatedly washed with deionized water and ethanol until neutral to obtain a wet supercrosslinked polymer supported on phenyl-modified siloxane.

[0097] Step 2: Microsphere surface functionalization

[0098] All the wet material obtained in step 1 was redispersed in 20 kg of ethanol and transferred to a 50 L reactor. 1.5 kg of KH792 silane coupling agent was added, a reflux condenser was installed, and the mixture was refluxed and stirred at 65 °C for 5 hours. After the reaction was completed, the mixture was cooled, filtered, and the solid product was washed twice with ethanol. Then, it was dried in a vacuum oven at 60 °C for 6 hours to obtain surface-amino-functionalized hypercrosslinked polymer sustained-release microsphere powder.

[0099] Step 3: Preparation of functional composite masterbatch

[0100] In a 30 L high-speed dispersion tank, 6.6 kg of deionized water was added, and a high-speed dispersion disc was installed. While stirring, all the functionalized slow-release microsphere powder obtained in step 2 was slowly added, along with 0.02 kg of graphene quantum dots. The dispersion disc was rotated at 2200 rpm, and the ultrasonic probe was simultaneously turned on. Ultrasonic dispersion was performed at 300 W for 30 minutes to ensure that the graphene quantum dots were fully adsorbed and dispersed on the surface and in the gaps between the slow-release microspheres, forming a uniform and stable functional composite masterbatch dispersion.

[0101] Step 4: Mixing the main emulsion

[0102] In a clean 100 L low-speed stirred tank, 78 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 500 rpm. The functional composite masterbatch dispersion obtained in step 3 was slowly and evenly added to the emulsion over 12 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0103] Step 5: Addition and blending of additives

[0104] While continuously stirring at 500 rpm, accurately add 2.5 kg of film-forming aid, 0.8 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 15 minutes. After the addition is complete, increase the stirring speed to 900 rpm and continue stirring for 25 minutes to ensure the system is thoroughly mixed.

[0105] Step 6: Compounding of hardening agents

[0106] While maintaining a stirring speed of 900 rpm, accurately add 1.2 kg of polyurethane hardener. After the addition is complete, continue stirring at this speed for 20 minutes to ensure that the polyurethane hardener is evenly distributed in the complex multiphase system.

[0107] Step 7: Adjusting viscosity and setting volume

[0108] Dissolve 0.3 kg of thickener in 3.3 kg of deionized water in a mixing tank and stir at 800 rpm for 10 minutes using a high-speed disperser to form a homogeneous slurry. Slowly add the thickener slurry to the main mixing vessel at 500 rpm. Then, rinse the mixing container with the remaining 3.4 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes to fully homogenize the system and achieve the required application viscosity.

[0109] Step 8: Maturation and Filtration

[0110] The product obtained in step 7 is pumped into a sealed curing tank and allowed to cure for 4 hours in a clean environment at 25°C and 50% relative humidity, allowing the bubbles to escape fully and the components to interact fully and reach equilibrium. Finally, the cured product is filtered through a 10μm precision filter and bottled to obtain the semi-transparent milky white intelligent invisible waterproofing agent.

[0111] Comparative Example 1: This comparative example uses a simplified, non-standard mixing process to illustrate the necessity of the stepwise in-situ polymerization and surface functionalization process of the present invention.

[0112] The waterproofing agent formulation in this comparative example is exactly the same as that in Example 1.

[0113] The formulation of the hypercrosslinked polymer composite system is as follows: 3.0 parts of phenyl-modified siloxane, 2.0 parts of divinylbenzene, 2.0 parts of benzene, 0.2 parts of anhydrous aluminum trichloride, and 1.5 parts of KH792.

[0114] Water-based main system formulation: 78 parts silicone-acrylic emulsion, 1.2 parts polyurethane hardener, 2.5 parts film-forming aid, 0.8 parts wetting and dispersing agent, 0.4 parts defoamer, 0.3 parts thickener, and 10 parts deionized water.

[0115] The waterproofing agent preparation method of this comparative example:

[0116] Step 1: Physical mixing to prepare composite masterbatch

[0117] In a 50 L stainless steel reactor, 3.0 kg of phenyl-modified siloxane, 2.0 kg of divinylbenzene, 2.0 kg of benzene, 0.2 kg of anhydrous aluminum trichloride, and 1.5 kg of KH792 were added simultaneously. Then, 6.6 kg of deionized water was added. A high-speed dispersion disc was installed, and stirring was started at 2000 rpm. Simultaneously, an ultrasonic probe was turned on, and the system was ultrasonically dispersed at 300 W for 30 minutes. Figure 1 The polymerization reaction and functionalization are completed in one step to obtain a physically mixed solution.

[0118] Step 2: Mixing the main emulsion

[0119] In a clean 100 L low-speed stirred tank, 78 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 500 rpm. The physical mixture obtained in step 1 was slowly and evenly added to the emulsion over 12 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0120] Step 3: Addition and blending of additives

[0121] While continuously stirring at 500 rpm, accurately add 2.5 kg of film-forming aid, 0.8 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 15 minutes. After the addition is complete, increase the stirring speed to 900 rpm and continue stirring for 25 minutes.

[0122] Step 4: Compounding of hardening agents

[0123] While maintaining a stirring speed of 900 rpm, accurately add 1.2 kg of polyurethane hardener, and continue stirring at this speed for 20 minutes after the addition is complete.

[0124] Step 5: Adjusting viscosity and setting volume

[0125] Dissolve 0.3 kg of thickener in 3.3 kg of deionized water in a mixing tank and stir at 800 rpm for 10 minutes using a high-speed disperser to form a homogeneous slurry. Slowly add the thickener slurry to the main mixing vessel at 500 rpm. Then, rinse the mixing container with the remaining 3.4 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes.

[0126] Step 6: Maturation and Filtration

[0127] The product obtained in step 5 was pumped into a sealed curing tank and cured for 4 hours in a clean environment at 25°C and 50% relative humidity. Poor system stability was observed during the curing process. Finally, the cured product was filtered through a 5μm precision filter and bottled to obtain the finished product.

[0128] Comparative Example 2:

[0129] The waterproofing agent formulation in this comparative example does not contain KH792, as detailed below:

[0130] The formulation of the hypercrosslinked polymer composite system is as follows: 3.0 parts of phenyl-modified siloxane, 2.0 parts of divinylbenzene, 2.0 parts of benzene, and 0.2 parts of anhydrous aluminum trichloride.

[0131] Water-based main system formulation: 78 parts silicone-acrylic emulsion, 1.2 parts polyurethane hardener, 2.5 parts film-forming aid, 0.8 parts wetting and dispersing agent, 0.4 parts defoamer, 0.3 parts thickener, and 10 parts deionized water.

[0132] The waterproofing agent preparation method of this comparative example:

[0133] Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres

[0134] In a dry 50 L jacketed glass reactor, 3.0 kg of phenyl-modified siloxane, 2.0 kg of divinylbenzene, and 2.0 kg of benzene were added. A frame-type stirrer was installed, and stirring was started at 400 rpm at room temperature for 30 minutes to form a homogeneous and transparent organic mixture. Ice-salt water was circulated through the reactor jacket to cool the system and maintain it at 0–5 °C. Under continuous stirring and low temperature, 0.2 kg of powdered anhydrous aluminum trichloride catalyst was rapidly added. This low-temperature reaction was maintained for 1.5 hours. Subsequently, the ice-salt water was removed, and the system was allowed to naturally heat to 50 °C, where the reaction continued for 8 hours. After the reaction was complete, the reaction mixture was slowly poured into ice water containing dilute hydrochloric acid for quenching, and the solid product was obtained by filtration. The product was repeatedly washed with deionized water and ethanol until neutral to obtain a wet supercrosslinked polymer loaded with phenyl-modified siloxane. This wet material was dried in a vacuum oven at 60 °C for 6 hours to obtain unfunctionalized supercrosslinked polymer sustained-release microsphere powder.

[0135] Step 2: Preparation of composite masterbatch

[0136] In a 30 L high-speed dispersion tank, 6.6 kg of deionized water was added, and a high-speed dispersion disc was installed. While stirring, all the unfunctionalized slow-release microsphere powder obtained in step 1 was slowly added. The dispersion disc was rotated at 2000 rpm, and the ultrasonic probe was simultaneously turned on. The mixture was ultrasonically dispersed at 300 W for 30 minutes to obtain a masterbatch dispersion.

[0137] Step 3: Mixing the main emulsion

[0138] In a clean 100 L low-speed stirred tank, 78 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 500 rpm. The masterbatch dispersion obtained in step 2 was slowly and evenly added to the emulsion over 12 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0139] Step 4: Addition and blending of additives

[0140] While continuously stirring at 500 rpm, accurately add 2.5 kg of film-forming aid, 0.8 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 15 minutes. After the addition is complete, increase the stirring speed to 900 rpm and continue stirring for 25 minutes.

[0141] Step 5: Compounding of hardening agents

[0142] While maintaining a stirring speed of 900 rpm, accurately add 1.2 kg of polyurethane hardener, and continue stirring at this speed for 20 minutes after the addition is complete.

[0143] Step 6: Adjusting viscosity and setting volume

[0144] Pre-dissolve 0.3 kg of thickener in 3.3 kg of deionized water in a mixing tank, and stir at 800 rpm for 10 minutes using a high-speed disperser to form a homogeneous slurry. Slowly add the thickener slurry to the main mixing vessel at 500 rpm. Then, rinse the mixing container with the remaining 8.2 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes.

[0145] Step 7: Mature and Filter

[0146] The product obtained in step 6 is pumped into a sealed curing tank and cured for 4 hours in a clean environment at 25°C and 50% relative humidity. Finally, the cured product is filtered through a 5μm precision filter and bottled to obtain the finished product.

[0147] Table 1. Performance test results of the smart slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer.

[0148] In summary, based on the comparative test results of the examples and comparative examples in Table 1, the intelligent slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer provided by this invention not only endows building substrates with excellent superhydrophobicity but also possesses superior long-term self-healing ability and durability. The fundamental reason lies in the innovative dual composite technology route of "in-situ polymerization-island encapsulation" and "π-stacking synergistic regulation": during the formation of its hydrophobic three-dimensional network, the hypercrosslinked polymer directly encapsulates phenyl-modified siloxanes, forming a firmly bonded "island structure," solving the problems of easy leakage and low loading rate inherent in traditional adsorption loading methods; its intrinsic hydrophobic properties have excellent compatibility with organic systems, ensuring high coating transparency; after surface functionalization with KH792, stable composite with aqueous emulsions is achieved. On the other hand, the introduced graphene quantum dots (GQDs) generate π-π stacking interactions with the aromatic structures in the system, constructing a reversible "secondary dynamic lock" inside and on the surface of the "island structure." When the coating is damaged, this dual-action structure enables more precise stress triggering and graded response release, resulting in faster repair speed and longer repair life.

[0149] Compared with existing technologies (including mesoporous silica-based sustained-release systems), the beneficial effects of this invention are specifically demonstrated through a system performance comparison:

[0150] (1) The in-situ polymerization process enables the carrier synthesis and functional loading to be completed in one step, which significantly simplifies the process. The formed "island structure" makes the hydrophobic agent load more robust, the slow release more intelligent, the self-healing response faster, and the cycle life longer (as shown in performance 9 and 10).

[0151] (2) The introduced graphene quantum dots further finely controlled the release dynamics of the hydrophobic agent through the synergistic effect of π-π stacking. While maintaining the high transparency of the coating, the recovery speed of superhydrophobicity (reduced roll angle, performance 4) and self-healing cycle durability (increased repair times, performance 10) were significantly improved, achieving performance gain optimization (as shown in Example 3).

[0152] (3) As a fully organic carrier, the hypercrosslinked polymer has excellent compatibility with the coating resin matrix, which not only ensures extremely high transparency, but also its mechanical reinforcement effect enables the coating to simultaneously improve wear resistance (performance 5) and aging resistance (performance 8).

[0153] (4) The dual coupling effect of KH792 is the key to constructing a stable and homogeneous composite system. Its absence (Comparative Example 2) will directly lead to severe phase separation of hydrophilic / hydrophobic components and complete product failure; its improper application (simple physical mixing in Comparative Example 1) will also lead to incomplete reaction and severe performance degradation, thus proving the necessity of the stepwise-sequential reaction process of the present invention.

[0154] (5) By adjusting the proportion of polymer monomers, the type and amount of hydrophobic agent, and the addition of graphene quantum dots, the penetration depth, repair rate and coating hardness of the product can be flexibly adjusted while maintaining high stealth effect, so as to meet diverse application needs.

[0155] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of their technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An invisible waterproofing agent based on "double-lock" slow-release microspheres, characterized in that, This invisible waterproofing agent introduces graphene quantum dots into an in-situ polymerized hypercrosslinked polymer carrier to construct a dual composite mechanism of "covalent anchoring-π stacking," enabling precise control of the hydrophobic agent release kinetics. This invisible waterproofing agent consists of a hypercrosslinked polymer composite system and an aqueous main system. The aforementioned hypercrosslinked polymer composite system is formed by in-situ polymerization of the following raw materials in parts by mass: 2.0-4.0 parts of phenyl-modified siloxane, 3.0-6.0 parts of polymeric monomer, 0.1-0.4 parts of catalyst, 1.0-2.0 parts of silane coupling agent, and 0.001-0.05 parts of graphene quantum dots.

2. The invisible waterproofing agent based on "double-locking" slow-release microspheres according to claim 1, characterized in that, The water-based main system components are in the following mass proportions: 75-82 parts silicone-acrylic emulsion, 1.0-1.5 parts polyurethane hardener, 2.0-3.0 parts film-forming aid, 0.5-1.0 parts wetting and dispersing agent, 0.3-0.6 parts defoamer, 0.2-0.5 parts thickener, and 8-12 parts deionized water.

3. The invisible waterproofing agent based on "double-locking" slow-release microspheres according to claim 1, characterized in that, The phenyl-modified siloxane is at least one of phenyl hydrogen-containing silicone oil or hydroxyl-terminated phenyl silicone oil, with a phenyl content of 20% to 40% and a viscosity of 300 to 800 mPa·s. In the system, it serves as both a coated hydrophobic repair agent and an organic phase medium for polymerization. Its phenyl structure can generate π-π stacking interactions with graphene quantum dots.

4. The invisible waterproofing agent based on "double-locking" slow-release microspheres according to claim 1, characterized in that, The polymeric monomer comprises a crosslinking monomer and a comonomer; the crosslinking monomer is divinylbenzene, and the amount used is 1.5 to 3.0 parts; the comonomer is benzene or toluene, and the amount used is 1.5 to 3.0 parts.

5. The invisible waterproofing agent based on "double-locking" slow-release microspheres according to claim 4, characterized in that, The crosslinking monomer and comonomer are used in a 1:1 ratio. The crosslinking monomer and comonomer undergo Friedel-Crafts alkylation reaction under the action of a catalyst to form a three-dimensional hypercrosslinked polymer network.

6. The invisible waterproofing agent based on "double-locking" slow-release microspheres according to claim 5, characterized in that, The graphene quantum dots are nanoparticles with a size of less than 10 nm and rich in carboxyl or hydroxyl groups on their surface. The amount of graphene quantum dots added is preferably 0.001% to 0.05% of the total mass of the waterproofing agent. In the system, the graphene quantum dots can combine with the aromatic structure of phenyl-modified siloxane and hypercrosslinked polymer network through π-π stacking to form a reversible "secondary dynamic lock", thereby finely controlling the release behavior of the hydrophobic agent.

7. A method for preparing an invisible waterproofing agent based on "double-locking" sustained-release microspheres, characterized in that, This preparation method is used to prepare the invisible waterproofing agent as described in claim 1; the specific steps are as follows: Step 1: In-situ polymerization to prepare hydrophobic sustained-release microspheres; In a dry reactor, phenyl-modified siloxane, divinylbenzene, and benzene are mixed in proportion and stirred at room temperature to form a homogeneous oil phase. The system is cooled to 0–5°C, and anhydrous aluminum trichloride catalyst is rapidly added under stirring. After maintaining the low temperature reaction for 1–2 hours, the temperature is raised to 40–60°C and the reaction continues for 6–12 hours. After the reaction is completed, the mixture is quenched, filtered, and washed to obtain a wet supercrosslinked polymer loaded with a hydrophobic agent. Step 2: Microsphere surface functionalization The wet supercrosslinked polymer was dispersed in ethanol, and silane coupling agent KH792 was added. The mixture was refluxed at 60-70°C for 4-6 hours. After the reaction was completed, the mixture was separated, washed and dried to obtain functionalized supercrosslinked polymer sustained-release microspheres with amino groups on the surface. Step 3: Preparation of composite masterbatch; Functionalized hypercrosslinked polymer slow-release microspheres were mixed with an appropriate amount of deionized water, and graphene quantum dots of the formulation amount were added. The mixture was ultrasonically dispersed at 300W power for 20-30 minutes to allow the graphene quantum dots to be fully adsorbed and dispersed on the surface and gaps of the slow-release microspheres, forming a uniform composite masterbatch dispersion. Step 4: Compound with the water-based main system; Place the silicone-acrylic emulsion in a reactor and stir at low speed. Slowly add the composite masterbatch dispersion into the emulsion. Step 5: Addition and homogenization of additives; Add the film-forming aid, wetting and dispersing agent and defoamer in sequence while stirring continuously. After the addition is complete, increase the stirring speed to 800-1000 rpm and continue stirring for 20-30 minutes. Step 6: Strengthening and fixing adhesion; Maintain the stirring speed, add the polyurethane hardener, and continue stirring to ensure uniform mixing; pre-dissolve the thickener in the remaining deionized water and add it to the system, then reduce the speed to 200-300 rpm and continue stirring for 30-40 minutes; Step 7: Maturation and Finished Product; The obtained product was left to stand and mature at room temperature, and then filtered through a precision filter to obtain a finished product of a smart slow-release invisible waterproofing agent based on in-situ polymerized hypercrosslinked polymer.

8. The method for preparing the invisible waterproofing agent based on "double-locking" sustained-release microspheres according to claim 7, characterized in that, In step 1, the in-situ polymerization reaction conditions are: a low-temperature stage of 0-5°C for 1-2 hours, and a heating stage of 40-60°C for 6-12 hours.

9. The method for preparing the invisible waterproofing agent based on "double-locking" sustained-release microspheres according to claim 7, characterized in that, In step 2, the surface functionalization conditions are: reflux reaction at 60-70°C for 4-6 hours in ethanol solvent.

10. The method for preparing the invisible waterproofing agent based on "double-locking" sustained-release microspheres according to claim 7, characterized in that, In step 7, the curing environment temperature is 20-30℃ and the relative humidity is 40%-60%.

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