Mesoporous silica composite intelligent slow-release invisible waterproof agent and preparation method thereof

Abstract

The invention discloses a mesoporous silica composite intelligent slow-release invisible waterproof agent and a preparation method thereof, through intelligent drug loading and slow release effects of aminated mesoporous silica, the self-repairing capability of a waterproof function is realized, and the problem of insufficient durability of a traditional waterproof agent is solved; a step-by-step composite process of vacuum impregnation and pre-hydrolysis coupling is adopted, hydrophobic sustained-release microspheres are firstly constructed, and then stable bridging of the hydrophobic sustained-release microspheres and a water-based emulsion is realized through KH792, so that realization of an intelligent function and long-term stability of a system are ensured; through the dual coupling effect of KH792, a firm chemical bonding network is constructed among the organic emulsion, the inorganic nano filler and the building base material, and the adhesive force, the wear resistance and the weather resistance of the coating are remarkably improved; due to the nano spherical structure and uniform particle size distribution of aminated mesoporous silica, a nano enhanced and hydrophobic micro-nano structure is provided, and meanwhile, the high transparency and the invisible effect of the coating are guaranteed to the maximum extent.

Description

Technical Field

[0001] This invention belongs to the field of building chemical protective materials technology, specifically relating to an intelligent slow-release invisible waterproofing agent for building exterior walls. This waterproofing agent has the characteristics of 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, cracking, weathering, dirt accumulation, and decreased durability. This not only affects the aesthetics of the building but also significantly shortens its lifespan. Traditional waterproofing materials for building exterior walls mostly use silicone resins, acrylic emulsions, or fluorocarbon resins as the main film-forming substances. While they possess a certain degree of waterproofing and weather resistance, it is difficult to achieve an ideal balance between high transparency, long-term durability, self-cleaning ability, and environmental friendliness. Specifically, existing technologies have the following prominent problems: silicone-based waterproofing agents, although having good permeability and water-repellent effects, have low mechanical strength after film formation and insufficient abrasion and scratch resistance; acrylic coatings have strong adhesion and high transparency, but limited water resistance, stain resistance, and continuous hydrophobicity; while fluorocarbon resin materials have excellent weather resistance, they are expensive, and some products contain environmentally unfriendly components. More importantly, these traditional materials generally lack intelligent response capabilities, and their protective function gradually declines over time, failing to achieve long-term self-repair.

[0003] In recent years, some studies have attempted to improve the performance of waterproofing agents by introducing novel nanomaterials. For example, patent CN120058265A discloses an enhanced waterproofing agent for gypsum-based composite cementitious materials, which uses a nanolayered structure to improve the mechanical properties and water resistance of the material. However, this technology is mainly designed for gypsum substrates and lacks universality for various exterior wall substrates such as concrete and stone, and it does not have self-healing capabilities. Another patent, CN120795765A, reports a technical solution using silane-functionalized graphene oxide and waterborne polyurethane composites. Although this improves the mechanical strength and water resistance of the coating to some extent, the graphene oxide nanosheets are prone to stacking in the system and are difficult to disperse stably, resulting in storage stability issues. Furthermore, its dark color may affect the transparency and invisibility of the coating, and the raw material cost is relatively high. In addition, the gel-capillary penetrating crystalline waterproofing agent involved in patent CN120082230A mainly serves the waterproofing of the internal structure of concrete, while the polyurea self-healing waterproof coating involved in patent CN119978969A is difficult to meet the requirements of high transparency. These existing technologies are all difficult to meet the dual requirements of "invisible protection" and "long-lasting intelligent durability" for building exterior walls.

[0004] Therefore, there is an urgent need to develop a new type of exterior wall waterproofing agent that is environmentally friendly, easy to construct, can completely maintain the original appearance of the building after construction without causing visual impact, and has intelligent response and long-term self-healing protection functions, so as to solve the technical bottleneck of the difficulty in synergistically balancing transparency, durability, functionality and environmental protection in existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a mesoporous silica composite intelligent slow-release invisible waterproofing agent and its preparation method. In view of the defects in the prior art, the invention prepares a mesoporous silica composite intelligent slow-release invisible waterproofing agent with high transparency, excellent waterproofing, excellent wear resistance and long-lasting self-healing function.

[0006] To solve the above-mentioned technical problems, the following technical solution is adopted.

[0007] A mesoporous silica composite smart slow-release invisible waterproofing agent, which is composed of a silane-mesoporous silica composite system and a water-based main system.

[0008] The mass fractions of the components in the silane-mesoporous silica composite system are as follows: 1.5-2.5 parts of N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH792), 2.0-4.0 parts of aminated mesoporous silica nanospheres, and 1.0-2.0 parts of phenyl-modified siloxane.

[0009] The water-based main system components are in the following mass fractions: 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.

[0010] After optimization, N-β-aminoethyl-γ-aminopropyltrimethoxysilane has an amino content ≥95% and a purity ≥98%.

[0011] After optimization, the aminated mesoporous silica nanospheres are functionalized materials whose surfaces are modified with aminopropyltriethoxysilane, with a particle size of 50-200 nm and a pore size of 3-8 nm. Phenyl-modified siloxane is loaded into its mesoporous channels by vacuum impregnation to form hydrophobic microspheres with sustained-release function.

[0012] Preferably, the phenyl-modified siloxane is at least one of phenyl hydrogen-containing silicone oil or hydroxyl-terminated phenyl silicone oil; its phenyl content is 20% to 40%, and its viscosity is 300 to 800 mPa·s.

[0013] After optimization, the solid content of the silicone-acrylic emulsion is 40% to 50%, and the glass transition temperature is 10 to 20°C.

[0014] After optimization, the film-forming aid is 12-ol ester.

[0015] After optimization, the thickener is a hydrophobically modified alkali-swellable thickener with a solid content of 28% to 32%.

[0016] After optimization, the wetting and dispersing agent is selected from one or more of the following: sodium polyacrylate, polycarboxylate ethers, alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, octyl phosphate, castor oil polyoxyethylene ethers, and styrene-maleic anhydride copolymers.

[0017] After optimization, the defoamer is selected from one or more of the following: polydimethylsiloxane, polyether-modified polysiloxane, polypropylene glycol ether, white oil, tributyl phosphate, hydrophobic silica, and polyethylene wax.

[0018] A method for preparing a mesoporous silica composite smart slow-release invisible waterproofing agent includes the following steps.

[0019] (1) The hydrophobic agent phenyl-modified siloxane was slowly added dropwise to the aminated mesoporous silica nanospheres under vacuum conditions, so that the hydrophobic agent was fully impregnated and loaded in the mesoporous channels to obtain hydrophobic slow-release microspheres.

[0020] (2) N-β-aminoethyl-γ-aminopropyltrimethoxysilane was mixed with 1 / 3 of the total amount of deionized water at room temperature and pre-hydrolyzed to obtain a clear hydrolyzed silane solution.

[0021] (3) Add hydrophobic slow-release microspheres to a hydrolyzed silane solution and sonicate to cause N-β-aminoethyl-γ-aminopropyltrimethoxysilane to undergo a coupling reaction with the amino groups on the surface of the slow-release microspheres to form a functional composite masterbatch.

[0022] (4) Place the silicone-acrylic emulsion in a reactor and slowly add the functional composite masterbatch into the emulsion while stirring at low speed.

[0023] (5) 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.

[0024] (6) Keep stirring speed, add polyurethane hardener, and continue stirring until the mixture is uniform.

[0025] (7) After pre-dissolving the thickener in the remaining deionized water, add it to the system and then reduce the stirring speed.

[0026] (8) Let the obtained product stand and mature, then filter it through a filter to obtain the invisible waterproofing agent.

[0027] After optimization, the vacuum impregnation conditions in step (1) are: temperature 50-60℃, vacuum degree -0.09 MPa, and impregnation time 4-6 hours.

[0028] After optimization, the pre-hydrolysis conditions in step (2) are stirring at 300-500 rpm for 30-45 minutes at room temperature.

[0029] After optimization, in step (3), the ultrasonic processing power is 300W and the processing time is 20-30 minutes.

[0030] After optimization, in step (4), the stirring speed is 400-600 rpm and the feeding time is 10-15 minutes.

[0031] After optimization, in step (5), the stirring speed is increased to 800-1000 rpm and the stirring time is 20-30 minutes.

[0032] After optimization, in step (6), the stirring speed is 800-1000 rpm and the stirring time is 15-25 minutes.

[0033] After optimization, in step (7), the rotation speed is reduced to 200-300 rpm, and stirring is continued for 30-40 minutes.

[0034] After optimization, in step (8), the curing environment temperature is 20-30℃, the relative humidity is 40%-60%, and the curing time is 3-5 hours.

[0035] The above technical solution has the following beneficial effects.

[0036] This invention proposes a mesoporous silica composite intelligent slow-release invisible waterproofing agent with 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, with a penetration depth of 2-5mm into concrete substrates, a water contact angle ≥150°, a roll-off angle ≤10°, and a weight loss of ≤0.015g (750g / 500r). It also exhibits excellent adhesion to various building materials such as concrete, stone, and bricks.

[0037] Through experimentation, the inventors discovered that loading phenyl-modified siloxanes into the pores of aminated mesoporous silica nanospheres using a specific vacuum impregnation process can effectively achieve intelligent slow-release and self-healing functions of hydrophobic components. Aminated mesoporous silica acts as both a carrier of the hydrophobic agent and a nano-reinforcing filler in the system. Its abundant mesoporous structure enables the controlled release of the hydrophobic agent, and the amino functional groups on its surface undergo a coupling reaction with KH792, forming a stable organic-inorganic composite network. KH792 plays a dual coupling bridging role in the system; its hydrolyzed silanol groups can bind to the inorganic substrate, while its organic amino groups can interact with the silicone-acrylic emulsion and the amino groups on the surface of the mesoporous silica, significantly improving the adhesion and durability of the coating.

[0038] The beneficial effects of this invention are mainly reflected in the following aspects.

[0039] (1) Through the intelligent drug loading and sustained release effect of aminated mesoporous silica, the self-repairing ability of waterproof function is realized, solving the problem of insufficient durability of traditional waterproof agents; (2) By adopting a stepwise composite process of vacuum impregnation and pre-hydrolysis coupling, "hydrophobic sustained-release microspheres" are first constructed, and then KH792 is used to achieve stable bridging between them and water-based emulsions, ensuring the realization of intelligent function and long-term stability of the system; (3) Through the dual coupling effect of KH792, a strong chemical bond network is constructed between organic emulsion, inorganic nanofiller and building substrate, significantly improving the adhesion of the coating. Wear resistance and weather resistance; (4) The nano-spherical structure and uniform particle size distribution of aminated mesoporous silica provide nano-reinforcement and hydrophobic micro-nano structure while maximizing the high transparency and invisibility of the coating; (5) The high refractive index of phenyl modified siloxane is well matched with the system. One part of it directly participates in film formation to provide initial hydrophobicity, and the other part is encapsulated for self-healing, which together ensures the comprehensive performance of the coating; (6) The product integrates intelligent slow release, self-healing, superhydrophobicity and high transparency, and has a long-term reliable protective effect on the exterior wall of the building without changing its appearance. Attached Figure Description

[0040] The invention will now be further described with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic diagram illustrating the mechanism of action of the mesoporous silica composite intelligent slow-release invisible waterproofing agent of the present invention. Detailed Implementation

[0042] This invention aims to provide a mesoporous silica composite intelligent slow-release invisible waterproofing agent and its preparation method. Through a specific vacuum impregnation process, phenyl-modified siloxane is loaded into the pores of aminated mesoporous silica nanospheres, effectively achieving intelligent slow-release and self-healing functions of the hydrophobic component. The aminated mesoporous silica acts as both a carrier of the hydrophobic agent and a nano-reinforcing filler in the system. Its abundant mesoporous structure enables the controlled release of the hydrophobic agent. The amino functional groups on the surface undergo a coupling reaction with KH792, forming a stable organic-inorganic composite network. KH792 plays a dual coupling bridging role in the system; its hydrolyzed silanol groups can bind to the inorganic substrate, while its organic amino groups can interact with the silicone-acrylic emulsion and the amino groups on the surface of the mesoporous silica, significantly improving the adhesion and durability of the coating.

[0043] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0044] Example 1.

[0045] The formulation of the mesoporous silica composite smart slow-release invisible waterproofing agent in this embodiment is as follows: The formulation of the silane-mesoporous silica composite system is as follows: 2.0 parts of KH792, 3.0 parts of aminated mesoporous silica nanospheres, and 1.5 parts of phenyl-modified siloxane.

[0046] 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.

[0047] The method for preparing the invisible waterproofing agent in this embodiment.

[0048] Step 1: Prepare hydrophobic sustained-release microspheres.

[0049] 1.5 kg of phenyl-modified siloxane was slowly added dropwise to 3.0 kg of aminated mesoporous silica nanospheres at a rate of 0.25 kg / h using a constant flow pump under conditions of 55 °C and -0.09 MPa vacuum. The system temperature was maintained at 55 ± 2 °C, and the mixture was stirred continuously for 5 hours to ensure that the phenyl-modified siloxane was fully impregnated and loaded into the mesoporous channels, thus obtaining hydrophobic slow-release microspheres, which were then transferred to a sealed container for later use.

[0050] Step 2: Silane pre-hydrolysis.

[0051] In a 50 L stainless steel reactor with jacketed heating and variable frequency speed control, 3.3 kg of deionized water was added. A frame-type stirrer was installed, and stirring was started at room temperature with a speed of 400 rpm. 2.0 kg of KH792 was accurately added using a precision metering pump over a period of 15 minutes. After addition, stirring was maintained at 400 rpm for 40 minutes to perform a pre-hydrolysis reaction, yielding a clear and transparent hydrolyzed silane solution.

[0052] Step 3: Prepare functional composite masterbatch.

[0053] Add all the hydrophobic slow-release microspheres obtained in step 1 to the hydrolyzed silane solution obtained in step 2. Stop the frame stirring, replace the stirring paddle with a high-speed dispersion disc, control the speed at 2000 rpm, and simultaneously turn on the ultrasonic probe inserted below the liquid surface. Perform ultrasonic dispersion of the system at 300W power for 25 minutes to allow KH792 to fully couple with the amino groups on the surface of the slow-release microspheres, forming a homogeneous and stable functional composite masterbatch.

[0054] Step 4: Mix the main emulsion.

[0055] 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 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.

[0056] Step 5: Addition and blending of additives.

[0057] 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.

[0058] Step 6: Compounding of hardening agents.

[0059] 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.

[0060] Step 7: Adjust viscosity and set volume.

[0061] 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.

[0062] Step 8: Mature and filter.

[0063] 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 a semi-transparent, milky-white invisible waterproofing agent.

[0064] Example 2.

[0065] The formulation of the mesoporous silica composite smart slow-release invisible waterproofing agent in this embodiment is as follows.

[0066] The formulation of the silane-mesoporous silica composite system is as follows: 1.8 parts of KH792, 2.5 parts of aminated mesoporous silica nanospheres, and 1.2 parts of phenyl-modified siloxane.

[0067] Water-based main system formulation: 80 parts silicone-acrylic emulsion, 1.0 part polyurethane hardener, 2.8 parts film-forming aid, 0.6 parts wetting and dispersing agent, 0.5 parts defoamer, 0.2 parts thickener, and 9.5 parts deionized water.

[0068] The method for preparing the invisible waterproofing agent in this embodiment.

[0069] Step 1: Prepare hydrophobic sustained-release microspheres.

[0070] 1.2 kg of phenyl-modified siloxane was slowly added dropwise to 2.5 kg of aminated mesoporous silica nanospheres at a rate of 0.2 kg / h using a constant flow pump under conditions of 50 °C and -0.09 MPa vacuum. The system temperature was maintained at 50 ± 2 °C, and the mixture was stirred continuously for 6 hours to ensure that the phenyl-modified siloxane was fully impregnated and loaded into the mesoporous channels, thus obtaining hydrophobic slow-release microspheres, which were then transferred to a sealed container for later use.

[0071] Step 2: Silane pre-hydrolysis.

[0072] In a 50 L stainless steel reactor with jacketed heating and variable frequency speed control, 3.2 kg of deionized water was added. A frame-type stirrer was installed, and stirring was started at room temperature with a speed of 300 rpm. 1.8 kg of KH792 was accurately added using a precision metering pump over a period of 12 minutes. After addition, stirring was maintained at 300 rpm for 45 minutes to perform a pre-hydrolysis reaction, yielding a clear and transparent hydrolyzed silane solution.

[0073] Step 3: Prepare functional composite masterbatch.

[0074] Add all the hydrophobic slow-release microspheres obtained in step 1 to the hydrolyzed silane solution obtained in step 2. Stop the frame stirring and replace the stirring paddle with a high-speed dispersion disc, controlling the speed at 1800 rpm. At the same time, turn on the ultrasonic probe inserted below the liquid surface and ultrasonically disperse the system at 300W power for 30 minutes to allow KH792 to fully couple with the amino groups on the surface of the slow-release microspheres, forming a homogeneous and stable functional composite masterbatch.

[0075] Step 4: Mix the main emulsion.

[0076] In a clean 100 L low-speed stirred tank, add 80 kg of silicone-acrylic emulsion, install an anchor-type agitator, and start stirring at 400 rpm. The functional composite masterbatch obtained in step 3 is then slowly and evenly added to the emulsion over 15 minutes using a constant flow pump, maintaining a stable feeding rate.

[0077] Step 5: Addition and blending of additives.

[0078] While continuously stirring at 400 rpm, accurately add 2.8 kg of film-forming aid, 0.6 kg of wetting and dispersing agent, and 0.5 kg of defoamer to the system sequentially, completing the addition of all aids within 12 minutes. After the addition is complete, increase the stirring speed to 800 rpm and continue stirring for 30 minutes to ensure the system is uniformly mixed.

[0079] Step 6: Compounding of hardening agents.

[0080] While maintaining a stirring speed of 800 rpm, accurately add 1.0 kg of polyurethane hardener. After the addition is complete, continue stirring at this speed for 25 minutes to ensure that the polyurethane hardener is evenly distributed in the complex multiphase system.

[0081] Step 7: Adjust viscosity and set volume.

[0082] Dissolve 0.2 kg of thickener in 3.2 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 this thickener slurry to the main mixing vessel at 400 rpm. Then, rinse the mixing container with the remaining 3.1 kg of deionized water and add it to the vessel. Reduce the stirring speed to 200 rpm and continue stirring for 40 minutes to fully homogenize the system and achieve the desired application viscosity.

[0083] Step 8: Mature and filter.

[0084] The product obtained in step 7 is pumped into a sealed curing tank and allowed to cure for 5 hours in a clean environment at 20°C and 60% 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 a semi-transparent, milky-white invisible waterproofing agent.

[0085] Example 3.

[0086] The formulation of the mesoporous silica composite smart slow-release invisible waterproofing agent in this embodiment is as follows.

[0087] The formulation of the silane-mesoporous silica composite system is as follows: 2.2 parts KH792, 3.5 parts aminated mesoporous silica nanospheres, and 1.8 parts phenyl-modified siloxane.

[0088] Water-based main system formulation: 76 parts silicone-acrylic emulsion, 1.3 parts polyurethane hardener, 2.3 parts film-forming aid, 0.9 parts wetting and dispersing agent, 0.4 parts defoamer, 0.4 parts thickener, and 8.5 parts deionized water.

[0089] The method for preparing the invisible waterproofing agent in this embodiment.

[0090] Step 1: Prepare hydrophobic sustained-release microspheres.

[0091] 1.8 kg of phenyl-modified siloxane was slowly added dropwise to 3.5 kg of aminated mesoporous silica nanospheres at a rate of 0.3 kg / h using a constant flow pump under conditions of 60 °C and -0.09 MPa vacuum. The system temperature was maintained at 60 ± 2 °C, and the mixture was stirred continuously for 4 hours to ensure that the phenyl-modified siloxane was fully impregnated and loaded into the mesoporous channels, thus obtaining hydrophobic slow-release microspheres, which were then transferred to a sealed container for later use.

[0092] Step 2: Silane pre-hydrolysis.

[0093] In a 50 L stainless steel reactor with jacketed heating and variable frequency speed control, 2.8 kg of deionized water was added. A frame-type stirrer was installed, and stirring was started at room temperature with a speed of 500 rpm. 2.2 kg of KH792 was accurately added using a precision metering pump over a period of 18 minutes. After addition, stirring was maintained at 500 rpm for 35 minutes to perform a pre-hydrolysis reaction, yielding a clear and transparent hydrolyzed silane solution.

[0094] Step 3: Prepare functional composite masterbatch.

[0095] Add all the hydrophobic slow-release microspheres obtained in step 1 to the hydrolyzed silane solution obtained in step 2. Stop the frame stirring and replace the stirring paddle with a high-speed dispersion disc, controlling the speed at 2200 rpm. At the same time, turn on the ultrasonic probe inserted below the liquid surface and ultrasonically disperse the system at 300W power for 20 minutes to allow KH792 to fully couple with the amino groups on the surface of the slow-release microspheres, forming a homogeneous and stable functional composite masterbatch.

[0096] Step 4: Mix the main emulsion.

[0097] In a clean 100 L low-speed stirred tank, 76 kg of silicone-acrylic emulsion was added, an anchor-type agitator was installed, and stirring was started at 600 rpm. The functional composite masterbatch obtained in step 3 was slowly and evenly added to the emulsion over 10 minutes using a constant flow pump, while maintaining a stable feeding rate.

[0098] Step 5: Addition and blending of additives.

[0099] While continuously stirring at 600 rpm, accurately add 2.3 kg of film-forming aid, 0.9 kg of wetting and dispersing agent, and 0.4 kg of defoamer to the system sequentially, completing the addition of all aids within 18 minutes. After the addition is complete, increase the stirring speed to 1000 rpm and continue stirring for 20 minutes to ensure the system is uniformly mixed.

[0100] Step 6: Compounding of hardening agents.

[0101] While maintaining a stirring speed of 1000 rpm, accurately add 1.3 kg of polyurethane hardener. After the addition is complete, continue stirring at this speed for 15 minutes to ensure that the polyurethane hardener is evenly distributed in the complex multiphase system.

[0102] Step 7: Adjust viscosity and set volume.

[0103] Dissolve 0.4 kg of thickener in 2.8 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 600 rpm. Then, rinse the mixing container with the remaining 2.9 kg of deionized water and add it to the vessel. Reduce the stirring speed to 300 rpm and continue stirring for 30 minutes to fully homogenize the system and achieve the required application viscosity.

[0104] Step 8: Mature and filter.

[0105] The product obtained in step 7 is pumped into a sealed curing tank and allowed to cure for 3 hours in a clean environment at 30°C and 40% 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 a semi-transparent, milky-white invisible waterproofing agent.

[0106] Comparative Example 1 The waterproofing agent formulation for this comparative example is as follows.

[0107] The formulation of the silane-mesoporous silica composite system is as follows: 2.0 parts of KH792, 3.0 parts of aminated mesoporous silica nanospheres, and 1.5 parts of phenyl-modified siloxane.

[0108] 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.

[0109] This comparative example demonstrates the preparation method of the waterproofing agent.

[0110] Step 1: Physical mixing to prepare composite masterbatch.

[0111] 3.0 kg of aminated mesoporous silica nanospheres, 2.0 kg of KH792 and 1.5 kg of phenyl-modified siloxane were simultaneously added to a 50 L stainless steel reactor, along with 3.3 kg of deionized water. A high-speed dispersion disc was installed, and the mixture was dispersed at 2000 rpm and 300 W ultrasonic power for 25 minutes to obtain a physically mixed functional composite masterbatch.

[0112] Step 2: Mix the main emulsion.

[0113] 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 obtained in step 1 was slowly and uniformly added to the emulsion over 12 minutes using a constant flow pump.

[0114] Step 3: Addition and blending of additives.

[0115] 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.

[0116] Step 4: Compounding of hardening agents.

[0117] 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.

[0118] Step 5: Adjust viscosity and set volume.

[0119] 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.

[0120] Step 6: Mature and filter.

[0121] The product obtained in step 5 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.

[0122] Comparative Example 2.

[0123] The waterproofing agent formulation for this comparative example is as follows.

[0124] Formulation of silane-mesoporous silica composite system: 3.0 parts of aminated mesoporous silica nanospheres and 1.5 parts of phenyl-modified siloxane.

[0125] 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 12.2 parts deionized water.

[0126] This comparative example demonstrates the preparation method of the waterproofing agent.

[0127] Step 1: Prepare hydrophobic sustained-release microspheres.

[0128] 1.5 kg of phenyl-modified siloxane was slowly added dropwise to 3.0 kg of aminated mesoporous silica nanospheres at a rate of 0.25 kg / h under conditions of 55 °C and -0.09 MPa vacuum using a constant flow pump. The system temperature was maintained at 55 ± 2 °C, and the mixture was stirred continuously for 5 hours to obtain hydrophobic slow-release microspheres, which were then transferred to a sealed container for later use.

[0129] Step 2: Mix the main emulsion.

[0130] 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 hydrophobic slow-release microspheres prepared in step 1 were added directly to the emulsion, with the feeding time controlled at 12 minutes.

[0131] Step 3: Addition and blending of additives.

[0132] 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.

[0133] Step 4: Compounding of hardening agents.

[0134] 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.

[0135] Step 5: Adjust viscosity and set volume.

[0136] 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 8.9 kg of deionized water and add it to the vessel. Reduce the stirring speed to 250 rpm and continue stirring for 35 minutes.

[0137] Step 6: Mature and filter.

[0138] The product obtained in step 5 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.

[0139] The waterproofing agents prepared in the above embodiments and comparative examples were subjected to performance tests, and the test results are shown in Table 1.

[0140] Table 1. Performance test results of mesoporous silica composite smart slow-release invisible waterproofing agent

[0141] Inspection items Test methods Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Concrete penetration depth (mm) JC / T 902-2002 4.8 3.2 5.5 3.5 Test invalid Paint film color and appearance GB / T 9761-2008 Colorless, transparent, and without a visible membrane Colorless, transparent, and without a visible membrane Colorless, transparent, and without a visible membrane Slight decrease in opalescent transparency Translucent with slight flocculation Water contact angle (°) GB / T 30447-2013 154 149 156 140 125 Roll angle (°) Water droplet volume 3μL, inclined plane method 12 16 10 25 >40 Abrasion resistance (750g / 500r) Weight loss (g) GB / T 1768-2006 0.015 0.018 0.014 0.028 0.038 <![CDATA[Acid resistance (5% H2SO4, 48h)]]> GB / T 9274-1988 No change No change No change Slight loss of light Obvious loss of gloss and localized blistering <![CDATA[Alkali resistance (saturated Ca(OH)2, 48h)]]> GB / T 9274-1988 No change No change No change Slight loss of light Obvious loss of gloss and localized blistering UV aging resistance (500h) GB / T 23987-2009 No change, level 0 No change, level 0 No change, level 0 Slightly yellowish, Grade 1 Noticeable powdering, Level 2 Self-healing effect (48 hours after scratch) *Observation after artificial scratching and measurement of water contact angle The hydrophobic corner at the scratch has recovered more than 90%. The hydrophobic angle at the scratch has recovered more than 85%. The hydrophobic corner at the scratch has recovered more than 92%. The scratch has recovered about 60%, but there are still obvious watermarks. Almost no recovery; the scratched area is completely hydrophilic. Storage stability (30 days, 50℃) GB / T 6753.3-1986 Pass, without layering Pass, without layering Pass, without layering Slight sedimentation can be restored by shaking. Severe stratification is irreversible

[0142] The comparative test results of the examples and comparative examples in Table 1 show that the mesoporous silica composite intelligent slow-release invisible waterproofing agent provided by the present invention not only endows building substrates with excellent superhydrophobicity, but also possesses excellent wear resistance, aging resistance, and long-term self-healing function. The fundamental reason lies in the following: Aminated mesoporous silica nanospheres, acting as intelligent carriers, achieve controllable loading and slow release of hydrophobic functional molecules through their rich mesoporous structure, thus constructing the coating's self-healing ability; KH792, as a bis-aminosilane coupling agent, forms a strong dual-coupling bridging network in the system, reacting with the amino groups on the surface of mesoporous silica on one hand, and combining with the silicone-acrylic emulsion and inorganic substrate on the other, significantly enhancing the compatibility and interfacial bonding between organic and inorganic components; a specific vacuum impregnation process ensures a high loading and stable presence of the hydrophobic agent in the mesoporous channels, while the pre-hydrolysis and ultrasonic dispersion processes guarantee the uniformity and stability of the functional composite masterbatch.

[0143] Compared with the prior art, the beneficial effects of the present invention are specifically reflected through the performance comparison of the system: (1) The introduction of aminated mesoporous silica and its intelligent slow-release mechanism enable the coating to have the damage self-repair ability that traditional waterproofing agents do not have, which significantly improves the durability and service life of the product; (2) The dual coupling effect of KH792 is the core of building a stable composite system. Its absence will directly lead to the separation of component phases and the complete failure of product performance, as shown in Comparative Example 2; (3) Vacuum impregnation and pre-hydrolysis stepwise composite process is the key to realizing the function of "hydrophobic slow-release microspheres". Its absence (such as the simple physical mixing in Comparative Example 1) will lead to a significant decrease in self-repair effect and the decay of initial performance; (4) By adjusting the loading of mesoporous silica, the amount of KH792 and the ratio of silicone acrylic emulsion, a series of products with different performance requirements such as high permeability, high hardness or rapid self-repair can be flexibly prepared while maintaining the basic invisibility effect.

Claims

1. A mesoporous silica composite intelligent slow-release invisible waterproofing agent, characterized in that: This waterproofing agent consists of a silane-mesoporous silica composite system and a water-based main system. The mass fractions of the components in the silane-mesoporous silica composite system are: 1.5-2.5 parts of N-β-aminoethyl-γ-aminopropyltrimethoxysilane, 2.0-4.0 parts of aminated mesoporous silica nanospheres, and 1.0-2.0 parts of phenyl-modified siloxane. The water-based main system components are in the following mass fractions: 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.

2. The mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: The aminated mesoporous silica nanospheres are functionalized materials whose surfaces are modified with aminopropyltriethoxysilane. They have a particle size of 50–200 nm and a pore size of 3–8 nm. Phenyl-modified siloxane is loaded into their mesoporous channels by vacuum impregnation to form hydrophobic microspheres with sustained-release function.

3. The mesoporous silica composite intelligent slow-release invisible waterproofing agent 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; its phenyl content is 20% to 40%, and its viscosity is 300 to 800 mPa·s.

4. The mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: The solid content of the silicone-acrylic emulsion is 40%–50%, and the glass transition temperature is 10–20°C.

5. The mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: The film-forming aid is 12-ol ester; the thickener is a hydrophobically modified alkali-swellable thickener with a solid content of 28% to 32%.

6. The preparation method of the mesoporous silica composite intelligent slow-release invisible waterproofing agent as described in claim 1, characterized in that... Includes the following steps: (1) The hydrophobic agent phenyl-modified siloxane was slowly added dropwise to the aminated mesoporous silica nanospheres under vacuum conditions, so that the hydrophobic agent was fully impregnated and loaded in the mesoporous channels to obtain hydrophobic slow-release microspheres. (2) N-β-aminoethyl-γ-aminopropyltrimethoxysilane was mixed with 1 / 3 of the total amount of deionized water at room temperature and pre-hydrolyzed to obtain a clear hydrolyzed silane solution; (3) Add hydrophobic slow-release microspheres to a hydrolyzed silane solution and sonicate to cause N-β-aminoethyl-γ-aminopropyltrimethoxysilane to undergo a coupling reaction with the amino groups on the surface of the slow-release microspheres to form a functional composite masterbatch. (4) Place the silicone-acrylic emulsion in a reactor and slowly add the functional composite masterbatch into the emulsion while stirring at low speed; (5) 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. (6) While maintaining the stirring speed, add the polyurethane hardener and continue stirring until the mixture is uniform; (7) Add the thickener to the system after pre-dissolving it in the remaining deionized water, and then reduce the stirring speed. (8) Let the obtained product stand and mature, then filter it through a filter to obtain the invisible waterproofing agent.

7. The preparation method of the mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: In step (1), the vacuum impregnation conditions are a temperature of 50-60°C, a vacuum degree of -0.09 MPa, and an impregnation time of 4-6 hours.

8. The preparation method of the mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: In step (2), the pre-hydrolysis conditions are stirring at 300-500 rpm for 30-45 minutes at room temperature.

9. The preparation method of the mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: In step (4), the stirring speed is 400-600 rpm and the feeding time is 10-15 minutes; in step (5), the stirring speed is increased to 800-1000 rpm and the stirring time is 20-30 minutes; in step (6), the stirring speed is 800-1000 rpm and the stirring time is 15-25 minutes; in step (7), the speed is reduced to 200-300 rpm and stirring is continued for 30-40 minutes.

10. The preparation method of the mesoporous silica composite intelligent slow-release invisible waterproofing agent according to claim 1, characterized in that: In step (8), the curing environment temperature is 20-30℃, the relative humidity is 40%-60%, and the curing time is 3-5 hours.

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