Composite waterproof material based on self-repairing microcapsules and preparation method

Abstract

The invention relates to the technical field of building materials, and discloses a self-repairing microcapsule-based composite waterproof material and a preparation method thereof, and the self-repairing microcapsule-based composite waterproof material comprises the following components by weight: 60-80 parts of modified organic silicon resin, 5-15 parts of nano clay (modified montmorillonite), 3-8 parts of a self-repairing microcapsule, 2-5 parts of a water-based cross-linking agent, and 0.5-2 parts of a dispersing aid. Stress generated by settlement and temperature change of a building structure can be effectively resisted, and cracks are reduced fundamentally; meanwhile, the material still keeps flexibility at the low temperature of-30 DEG C (without cracks when bent), and the technical bottleneck that a traditional material is prone to embrittlement in a cold region is broken through; more importantly, the 24-hour self-repairing rate is up to 92%, self-healing of cracks can be achieved without manual intervention, the service life of waterproof engineering is prolonged to more than two times that of a traditional material, the full-life-cycle maintenance cost is remarkably reduced, and a long-acting and reliable solution is provided for the field of building waterproofing.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a self-repairing microcapsule composite waterproof material and a preparation method thereof. Background Art

[0002] In the field of building materials technology, traditional polyurethane / asphalt waterproofing materials for waterproofing projects such as building roofs, basements, and tunnels have long faced key technical challenges, including insufficient durability, irreversible damage, poor environmental performance, and low-temperature embrittlement. These challenges include: UV rays and temperature fluctuations causing the materials to age and crack, requiring manual repair rather than self-healing; excessive levels of volatile organic compounds (VOCs) in solvent-based systems causing environmental pollution; and a sudden drop in material flexibility in cold environments, resulting in a loss of waterproofing performance. Furthermore, while some existing modified materials or additives attempt to address these issues, they often only address a single issue and fail to simultaneously address multiple performance requirements, including high strength, self-healing properties, long-term weather resistance, and environmental protection. Furthermore, the addition of these modified materials or additives can introduce new challenges, such as altering the original material formulation and affecting its compatibility with other building materials, further limiting the lifespan of the waterproofing project and its overall environmental performance.

[0003] In the field of building materials technology, traditional polyurethane / asphalt materials have four major problems for waterproofing building roofs, basements, and tunnels: poor durability and lack of self-healing ability, such as the reliance on manual repair of cracks, high costs, insufficient environmental protection, and poor low-temperature adaptability. These problems shorten project lifespans, increase costs, and hinder the development of green buildings. Therefore, these materials do not meet existing needs. To address this, we propose a self-healing microcapsule composite waterproofing material and its preparation method. Summary of the Invention

[0004] The present invention provides a self-repairing microcapsule composite waterproof material and a preparation method thereof, which have beneficial effects and solve the problems mentioned in the above background technology.

[0005] The present invention provides the following technical solution: a self-repairing microcapsule composite waterproof material: composed of the following components in parts by weight: 60-80 parts of modified silicone resin, 5-15 parts of nanoclay (modified montmorillonite), 3-8 parts of self-repairing microcapsules, 2-5 parts of water-based crosslinking agent, and 0.5-2 parts of dispersing aid.

[0006] As an optional solution based on a self-repairing microcapsule composite waterproof material described in the present invention, the self-repairing microcapsule adopts a core-shell structure design, the shell layer is polyurea formaldehyde, the thickness is 0.5-2μm, and the shear strength is ≥10MPa; the core contains a repair monomer and a graphene-loaded Grubbs catalyst.

[0007] As an optional solution based on a self-healing microcapsule composite waterproof material described in the present invention, the nanoclay is modified montmorillonite, which forms a "maze-like" barrier path in the silicone matrix, reducing the water vapor permeability by more than 60% compared with pure silicone.

[0008] As an optional solution based on a self-repairing microcapsule composite waterproof material described in the present invention, wherein: the material has a 24-hour self-repair rate of ≥80% within a temperature range of -20°C to 60°C, and a tensile strength recovery rate after repair of ≥85%.

[0009] As an optional solution based on the self-repairing microcapsule composite waterproof material described in the present invention, the material is a water-based system with a VOCs content of ≤5g / L, which meets environmental protection requirements.

[0010] As an optional solution based on the self-repairing microcapsule composite waterproof material described in the present invention, the modified silicone resin serves as the main film-forming substance, giving the material long-term weather resistance, a tensile strength of more than 12.5 MPa, and an elongation at break of more than 620%.

[0011] As an optional solution based on the self-repairing microcapsule composite waterproof material described in the present invention, the repair monomer of the self-repairing microcapsule is dicyclopentadiene, which realizes self-repair of cracks through ring-opening metathesis reaction.

[0012] As an optional solution based on the self-repairing microcapsule composite waterproof material described in the present invention, when the nanoclay content is 10 parts, the comprehensive performance of the material is optimal, with a tensile strength of 12.5 MPa and an elongation at break of 620%.

[0013] As an optional solution based on the self-repairing microcapsule composite waterproof material described in the present invention, the material is suitable for waterproofing treatment of building roofs, basements, tunnels and other projects, and has low-temperature flexibility (-30°C) without cracks.

[0014] This solution also proposes a method for preparing a self-repairing microcapsule composite waterproof material, comprising the following steps:

[0015] S1. Prepare or accurately weigh key raw materials such as modified nanoclay, microcapsule suspension containing repair monomer, and silicone resin prepolymer in advance to ensure that the raw materials meet the requirements;

[0016] S2. The microcapsule suspension and the silicone resin prepolymer are added to the modified nanoclay system, and the components are fully and evenly mixed using a high-speed shear mixing device to form a stable mixed system;

[0017] S3. Adding an appropriate amount of crosslinking agent to the mixed system to initiate a crosslinking reaction of the silicone resin prepolymer to construct the main structure of the material; adding other additives according to actual needs to improve the fluidity, stability and other properties of the material;

[0018] S4. The mixture after adding the additive is placed in a vacuum environment to remove internal bubbles by vacuuming to ensure the density of the material and avoid subsequent performance defects;

[0019] S5. Depending on the application scenario and substrate characteristics, select an appropriate coating method such as spraying, brushing, or rolling to evenly apply the degassed mixture to the target substrate surface to form a coating of a specified thickness;

[0020] S6. Place the coated substrate in an oven or other heating equipment set at 80°C for low-temperature curing to fully cross-link and cure the silicone resin prepolymer, forming a stable structure of the material while ensuring the stable existence of the microcapsules, so that the finished product has excellent comprehensive properties such as waterproofing and self-healing.

[0021] The present invention has the following beneficial effects:

[0022] 1. This self-healing microcapsule composite waterproof material and preparation method achieves a breakthrough in the mechanical properties and functionality of waterproof materials through the composite modification of silicone resin and nanoclay, combined with self-healing microcapsule technology. Experiments have shown that the material achieves a tensile strength of 12.5 MPa and an elongation at break of 620%, respectively, 52% and 38% higher than traditional polyurethane materials. This material can effectively resist stress caused by settlement and temperature changes in building structures, fundamentally reducing the occurrence of cracks. Furthermore, the material remains flexible (bending without cracking) at temperatures as low as -30°C, breaking through the technical bottleneck of traditional materials becoming brittle in cold regions. More importantly, its 24-hour self-healing rate is as high as 92%, allowing cracks to heal autonomously without human intervention, extending the lifespan of waterproofing projects to more than twice that of traditional materials, significantly reducing maintenance costs throughout the entire lifecycle, and providing a long-term, reliable solution for building waterproofing.

[0023] 2. This self-healing microcapsule composite waterproof material and its preparation method, through the synergistic design of a graphene-loaded Grubbs catalyst and a dicyclopentadiene repair monomer, imparts efficient self-healing capabilities across a wide temperature range (-20°C to 60°C). Experimental data shows that the material's repair rate reaches 85% even at -20°C, a 70% improvement over existing technologies (≤50%). This addresses the industry challenge of waterproofing layers becoming unrepairable after winter construction in cold regions. At 60°C, the repair rate further increases to 95%, and the tensile strength recovers to 92% of its original value after repair, ensuring the structural integrity of cracks in high-temperature, enclosed environments such as tunnels and basements. Furthermore, graphene's electrical and thermal conductivity accelerates the catalyst's activation efficiency at extreme temperatures, increasing the repair reaction rate by more than three times compared to traditional materials, truly achieving "all-weather, all-scenario" self-healing capabilities.

[0024] 3. This self-healing microcapsule composite waterproof material and preparation method, based on nanoclay content gradient experiments, pinpoints 10 parts per million as the optimal balance between mechanical strength, flexibility, and barrier properties. At 10 parts per million, the material achieves a tensile strength of 12.5 MPa (a 60% increase compared to no clay addition), while maintaining an elongation at break of 620%, avoiding the embrittlement caused by excessive clay (which can cause material breakage at 20 parts per million). More importantly, the "maze-like" barrier structure formed by the nanoclay flakes within the silicone matrix reduces the water vapor transmission rate by 60% compared to pure silicone, effectively blocking water and oxygen permeation and extending the service life of the waterproof layer in humid environments (such as basements and tunnels). Furthermore, the addition of 10 parts per million increases material cost by only 8%, while improving overall performance by over 30%. This achieves a precise balance of low cost and high performance, providing an economically viable technical path for large-scale engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the preparation process of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1: This example aims to promote the solution of four major problems in the field of building materials technology for waterproofing building roofs, basements and tunnels. Traditional polyurethane / asphalt materials have poor durability, lack of self-repairing ability, such as cracks relying on manual repair, high cost, insufficient environmental protection, and poor low-temperature adaptability, which lead to shortened project life and increased costs, hindering the development of green buildings. Please refer to Figure 1 , a self-repairing microcapsule composite waterproof material and preparation method, composed of the following components in parts by weight: 60-80 parts of modified silicone resin, 5-15 parts of nanoclay (modified montmorillonite), 3-8 parts of self-repairing microcapsules, 2-5 parts of water-based crosslinking agent, and 0.5-2 parts of dispersing aid;

[0028] The self-healing microcapsules adopt a core-shell structure design. The shell is made of polyurea formaldehyde, with a thickness of 0.5-2μm and a shear strength of ≥10MPa. The core contains the repair monomer and the graphene-loaded Grubbs catalyst. In specific implementation, it serves as the main film-forming substance, giving the material long-term weather resistance. Its tensile strength exceeds 12.5MPa and its elongation at break exceeds 620%. It can effectively resist the external forces such as stretching and bending that building structures are subjected to during use, reducing cracking caused by external forces, thereby improving the durability of the material.

[0029] Nanoclay is a modified montmorillonite clay that forms a "maze-like" barrier path within the silicone matrix, reducing the water vapor transmission rate by over 60% compared to pure silicone. This unique structure effectively blocks water penetration, enhancing the material's waterproof properties while also improving its mechanical properties.

[0030] A modified silicone resin serves as the primary film-forming material, imparting long-lasting weather resistance, a tensile strength exceeding 12.5 MPa, and an elongation at break exceeding 620%. The material utilizes a core-shell structure, with a polyurea-formaldehyde shell layer measuring 0.5-2 μm thick and possessing a shear strength of ≥10 MPa. This ensures structural integrity and protects the core during preparation, processing, and use. The core contains a repairing monomer and a graphene-loaded Grubbs catalyst. When cracks develop on the surface of the material, stress at the cracks causes the self-healing microcapsules to rupture, releasing the repairing monomer and catalyst. The repairing monomer polymerizes under the action of the catalyst, filling the cracks and enabling the material's self-healing function, reducing the need for manual repairs and lowering maintenance costs.

[0031] During specific implementation, the chemical cross-linking reaction between the components is promoted to form a denser three-dimensional network structure, further improving the mechanical properties and durability of the material. At the same time, it helps to improve the waterproof performance and chemical corrosion resistance of the material, so that solid particles such as nanoclay and self-healing microcapsules are evenly dispersed in the modified silicone resin, avoiding particle agglomeration and ensuring the uniformity and stability of the material's performance.

[0032] In this embodiment, a composite waterproof material based on self-healing microcapsules is prepared. By rationally selecting and combining components such as a modified silicone resin, nanoclay, self-healing microcapsules, a water-based crosslinker, and a dispersing agent, and optimizing the preparation process, the material exhibits excellent durability, self-healing properties, environmental performance, and low-temperature adaptability. Compared with traditional polyurethane / asphalt materials, this composite waterproof material effectively addresses the challenges of traditional materials, providing a high-performance, environmentally friendly, and economical solution for waterproofing building roofs, basements, and tunnels, with broad application prospects and market value.

[0033] Example 2: This example aims to solve the problem of diverse crack morphologies in actual projects and the varying repair efficiencies of existing self-repair mechanisms for different cracks. This example is an improvement on Example 1. For details, please refer to Figure 1 The self-healing microcapsules are constructed from dicyclopentadiene, a monomer that repairs cracks through a ring-opening metathesis reaction. Dicyclopentadiene is highly reactive and rapidly diffuses into the cracks after the microcapsules rupture due to cracks. Under the action of a catalyst, ring-opening metathesis occurs, producing a polymer that is highly compatible with the matrix and effectively fills the cracks. Compared to other repair monomers, dicyclopentadiene offers milder reaction conditions and superior product performance, significantly enhancing the material's self-maintenance capabilities, reducing the risk of leakage and extending the service life of building waterproofing structures.

[0034] The material exhibits a 24-hour self-repair rate of ≥80% within a temperature range of -20°C to 60°C, and a post-repair tensile strength recovery rate of ≥85%. The synergy of the various components allows the material to maintain this performance over a wide temperature range. While molecular motion is slow at low temperatures, dicyclopentadiene still reacts slowly; this reaction accelerates at higher temperatures. Experiments have shown that both the self-repair rate and tensile strength recovery rate meet the standards at various temperatures. This means that the material can consistently perform its waterproofing and self-repairing functions in both the frigid north and the scorching south, reducing the risk of waterproofing failure due to temperature fluctuations.

[0035] The material is a water-based system with a VOC content of ≤5g / L, meeting environmental protection requirements. In practice, the water-based system uses water as the dispersion medium, significantly reducing the use of organic solvents and lowering VOC emissions. Careful material selection and process control keep the content ≤5g / L, minimizing hazards to personnel and the environment. Furthermore, the water-based system has no pungent odor, making it more environmentally friendly. It also offers advantages such as easy application, fast drying, and high safety. This not only facilitates its adoption in various building waterproofing projects, but also aligns with the current trend of green building development.

[0036] This embodiment improves upon existing practices and features key advantages. Dicyclopentadiene is selected as the self-healing microcapsule repair monomer. It exhibits high activity and mild reaction conditions. Through a ring-opening metathesis reaction, it generates a polymer with excellent matrix compatibility. This polymer effectively fills cracks, enhances the material's self-maintenance, and reduces the risk of leakage. The material also exhibits excellent temperature adaptability, achieving a 24-hour self-healing rate exceeding 80% and a post-repair tensile strength recovery rate exceeding 85% within a wide temperature range of -20°C to 60°C. This material can reliably withstand diverse climate conditions and mitigate waterproofing failures caused by temperature fluctuations. Furthermore, the material utilizes a water-based system with a VOC content of ≤5g / L, offering significant environmental advantages. This not only reduces hazards to personnel and the environment, but also offers an odor-free, environmentally friendly construction process. Furthermore, it features easy application, fast drying, and high safety, aligning with the development trend of green buildings and possessing broad application prospects.

[0037] Example 3: This example aims to address the significant differences in stress and deformation in different building components (roofs, basements, and tunnels). It is known that nanoclay generally performs best when it is present at 10 parts per million. This example addresses the issue of how to refine its content based on the working conditions of each component and simultaneously optimize the proportions of other components to achieve the optimal balance of material performance in each scenario. This example is an improvement on Example 2. For details, please refer to the following. Figure 1 When the nanoclay content is 10 parts, the comprehensive performance of the material is optimal, with a tensile strength of 12.5MPa and an elongation at break of 620%. In specific implementation, when the nanoclay content is precisely controlled at 10 parts, it can maximize its synergistic effect with the matrix material, so that the material can achieve an ideal balance between strength and flexibility. It has sufficient tensile strength to withstand external forces and good elongation at break to adapt to structural deformation, and its comprehensive performance reaches the optimal level.

[0038] The material is suitable for waterproofing projects such as building roofs, basements, and tunnels. Its low-temperature flexural properties (-30°C) show no cracking. In practical applications, the material demonstrates broad applicability, effectively addressing the waterproofing needs of diverse engineering scenarios, including building roofs, basements, and tunnels. Its excellent low-temperature flexural properties (-30°C) demonstrate its flexibility and cold resistance, enabling it to maintain stable waterproofing even in cold conditions.

[0039] This solution also proposes a method for preparing a self-repairing microcapsule composite waterproof material, comprising the following steps:

[0040] S1. Prepare or accurately weigh key raw materials such as modified nanoclay, microcapsule suspension containing repair monomer, and silicone resin prepolymer in advance to ensure that the raw materials meet the requirements;

[0041] S2. The microcapsule suspension and the silicone resin prepolymer are added to the modified nanoclay system, and the components are fully and evenly mixed using a high-speed shear mixing device to form a stable mixed system;

[0042] S3. Adding an appropriate amount of crosslinking agent to the mixed system to initiate a crosslinking reaction of the silicone resin prepolymer to construct the main structure of the material; adding other additives according to actual needs to improve the fluidity, stability and other properties of the material;

[0043] S4. The mixture after adding the additive is placed in a vacuum environment to remove internal bubbles by vacuuming to ensure the density of the material and avoid subsequent performance defects;

[0044] S5. Depending on the application scenario and substrate characteristics, select an appropriate coating method such as spraying, brushing, or rolling to evenly apply the degassed mixture to the target substrate surface to form a coating of a specified thickness;

[0045] S6. Place the coated substrate in an oven or other heating equipment set at 80°C for low-temperature curing to fully cross-link and cure the silicone resin prepolymer, forming a stable structure of the material while ensuring the stable existence of the microcapsules, so that the finished product has excellent comprehensive properties such as waterproofing and self-healing.

[0046] In this example, controlling the nanoclay content is crucial for improving composite waterproofing material performance. Experiments show that a nanoclay content of 10 parts per million (p / s) achieves optimal overall performance. Its tensile strength reaches 12.5 MPa, providing strong resistance to external forces and reducing the risk of cracking. Its elongation at break reaches 620%, demonstrating excellent flexibility and ductility, allowing it to adapt to structural deformation and maintain the integrity of the waterproof layer.

[0047] This material has a wide range of applications and can be used for waterproofing projects such as building roofs, basements, and tunnels. Its low-temperature performance is particularly outstanding, with no cracks when bent at -30°C. Its cold-resistant and flexible properties ensure stable waterproofing even in cold regions or during winter, giving it a promising future.

[0048] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A self-repairing microcapsule composite waterproof material, characterized by: The invention is composed of the following components in parts by weight: 60-80 parts of modified silicone resin, 5-15 parts of nano clay (modified montmorillonite), 3-8 parts of self-repairing microcapsules, 2-5 parts of water-based crosslinking agent and 0.5-2 parts of dispersing aid.

2. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The self-repairing microcapsule adopts a core-shell structure design, the shell layer is polyurea formaldehyde, the thickness is 0.5-2 μm, and the shear strength is ≥10 MPa; the core contains a repair monomer and a graphene-loaded Grubbs catalyst.

3. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The nanoclay is modified montmorillonite, which forms a "maze-like" barrier path in the silicone matrix, reducing the water vapor transmission rate by more than 60% compared with pure silicone.

4. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The material has a 24-hour self-repair rate of ≥80% within a temperature range of -20°C to 60°C, and a tensile strength recovery rate after repair of ≥85%.

5. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The material is a water-based system with a VOCs content of ≤5g / L, which meets environmental protection requirements.

6. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The modified silicone resin serves as the main film-forming substance, giving the material long-term weather resistance, a tensile strength of more than 12.5 MPa, and an elongation at break of more than 620%.

7. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The repair monomer of the self-repairing microcapsule is dicyclopentadiene, which realizes self-repair of cracks through ring-opening metathesis reaction.

8. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: When the content of the nanoclay is 10 parts, the comprehensive performance of the material is optimal, with a tensile strength of 12.5 MPa and an elongation at break of 620%.

9. The self-repairing microcapsule composite waterproof material according to claim 1, characterized in that: The material is suitable for waterproofing of building roofs, basements, tunnels and other projects, and has low-temperature flexibility (-30°C) without cracks.

10. A method for preparing a self-repairing microcapsule composite waterproof material, according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Prepare or accurately weigh key raw materials such as modified nanoclay, microcapsule suspension containing repair monomer, and silicone resin prepolymer in advance to ensure that the raw materials meet the requirements; S2. The microcapsule suspension and the silicone resin prepolymer are added to the modified nanoclay system, and the components are fully and evenly mixed using a high-speed shear mixing device to form a stable mixed system; S3. Adding an appropriate amount of a crosslinking agent to the mixed system to initiate a crosslinking reaction of the silicone resin prepolymer to construct the main structure of the material; Add other additives according to actual needs to improve the fluidity, stability and other properties of the material; S4. The mixture after adding the additive is placed in a vacuum environment to remove internal bubbles by vacuuming to ensure the density of the material and avoid subsequent performance defects; S5. Depending on the application scenario and substrate characteristics, select an appropriate coating method such as spraying, brushing, or rolling to evenly apply the degassed mixture to the target substrate surface to form a coating of a specified thickness; S6. Place the coated substrate in an oven or other heating equipment set at 80°C for low-temperature curing to fully cross-link and cure the silicone resin prepolymer, forming a stable structure of the material while ensuring the stable existence of the microcapsules, so that the finished product has excellent comprehensive properties such as waterproofing and self-healing.

Images