Composite modified nanometer silicon acrylate grouting material, preparation method and application thereof

Abstract

The application discloses a kind of composite modified nano silicon acrylate grouting materials and preparation method and application, belong to underground engineering anti-seepage material technical field.The grouting material is made by the mixture of independently packed A component and B component;A component includes composite acrylate monomer, nano composite filler, modified functional additive, crosslinking agent, accelerator, pH regulator and deionized water;B component includes composite initiator, low-temperature activator, hydrolysis-resistant stabilizer and deionized water;Wherein, the composite acrylate monomer is composed of calcium acrylate, zinc acrylate and isobutyl methacrylate, and the nano composite filler is composed of nano zirconium oxide and nano montmorillonite.The application also discloses the preparation method of the material and its application in underground engineering anti-seepage.The material realizes the synergistic unity of low viscosity, high strength and low shrinkage, has wide temperature range adaptability, strong acid and alkali salt corrosion resistance and ultra-long storage stability.

Description

Technical Field

[0001] This invention belongs to the technical field of underground engineering seepage prevention and plugging materials, specifically relating to a composite modified nano-silicon acrylate grouting material and its preparation method and application. Background Technology

[0002] Currently, among underground engineering sealing materials, acrylate materials are widely used in the treatment of seepage in subway tunnels, water conservancy projects, and underground pipe corridors due to their advantages such as low viscosity, good injectability, and adjustable gel time. However, as underground engineering develops into deeper, longer, and more complex environments, the engineering conditions exhibit the harsh characteristics of multiple factors such as "high water pressure, high salinity, extreme temperature differences, and strong corrosion." Traditional acrylate grouting materials have exposed many technical bottlenecks when dealing with such complex environments, prominently manifested in the common problem of "outstanding single performance but unbalanced multiple performances."

[0003] To improve material performance, existing technologies have undertaken various modification attempts. Chinese patent application CN116217783A discloses a high-permeability nano-modified acrylate grouting material, which aims to improve material permeability and solidified strength by adding nano-modifiers and rubber additives. While this approach improves mechanical properties to some extent, its composition lacks specific design considerations for curing efficiency in extreme low-temperature environments (e.g., below -30°C) and long-term durability in strong acid, alkali, and high-salt media, making it difficult to meet the long-term leak-sealing requirements under complex chemical and climatic environments. Chinese patent application CN120535687A proposes a porous nanomaterial and acrylate composite grouting material, focusing on addressing inorganic filler dispersion and material shrinkage issues through porous nanomaterials. However, this technical solution primarily focuses on improving physical and mechanical properties, with limited effect on improving the material's resistance to hydrolysis aging and freeze-thaw cycles over a wide temperature range (especially high-temperature and high-humidity environments), failing to achieve a synergistic balance of comprehensive performance under various harsh environments.

[0004] The existing technical solutions described above still suffer from the following insurmountable technical defects in practical applications: 1) Insufficient dispersion and interfacial compatibility of nanofillers limit the upper limit of the material's overall performance. Although existing technologies introduce nanofillers, they mainly focus on adjusting the type and ratio of fillers, paying insufficient attention to the pretreatment process of the nanofillers themselves. Due to their huge specific surface energy, nanoparticles are prone to agglomeration, and simple physical mixing or conventional coupling agent treatment is insufficient to achieve uniform nanoscale dispersion in the polymer matrix. Filler agglomeration not only fails to exert its nano-reinforcing effect but also becomes a stress concentration point, causing microcracks to form in the material under stress, limiting the synergistic performance of achieving low viscosity (≤40 mPa·s) while maintaining high strength (≥7 MPa) and ultra-low shrinkage (≤1.5%). 2) Insufficient adaptability and stability to extreme wide temperature ranges (-35℃ to 85℃). Although existing technologies mention low-temperature resistance and hydrolysis resistance functional components, they are mainly aimed at low-temperature environments of -30℃. For extremely cold conditions below -35℃, their condensation efficiency may still decrease significantly. More importantly, existing technologies generally overlook the degradation of material performance under high-temperature (≥60℃) conditions. In underground engineering, due to geothermal activity, equipment operation, or seasonal changes, local ambient temperatures may reach 60-85℃. In such high-temperature and high-humidity environments, the ester bonds in ordinary acrylate materials are easily hydrolyzed, leading to a sharp decrease in strength and sealing failure. Existing technologies lack a systematic solution for the wide temperature range adaptability of "low-temperature curability and high-temperature hydrolysis resistance." 3) It is difficult to balance long-term storage stability and construction reliability. To solve the problem of nanofiller agglomeration and extend the shelf life, existing technologies often require the addition of complex dispersants or the use of energy-intensive preparation processes. However, this may lead to excessively high initial viscosity of the material, affecting its penetration ability in microcracks below 0.08mm. The effective shelf life of most existing products is only 3-6 months, and components A and B are prone to stratification, self-aggregation, or precipitation during storage, leading to inaccurate mixing ratios and uncontrolled setting time during on-site grouting, seriously affecting project quality and construction reliability.

[0005] Therefore, developing a composite modified acrylate grouting material that can truly achieve low viscosity, high strength, ultra-low shrinkage, resistance to extreme acid, alkali and salt corrosion, adaptability to a wide temperature range (-35℃ to 85℃) environment, and have ultra-long storage stability (≥12 months), and solving the process problems of easy agglomeration of nanofillers and poor batch stability in its industrial production, is a technical bottleneck that urgently needs to be overcome by those skilled in the art. Summary of the Invention

[0006] To address the technical problems of existing acrylate grouting materials in harsh underground engineering projects, which are unable to simultaneously achieve low viscosity, high strength, and ultra-low shrinkage, and cannot maintain long-term stability and ultra-long storage period (≥12 months) in a wide temperature range of -35℃ to 85℃ and in highly corrosive environments, this invention aims to provide a composite modified nano-silicon acrylate grouting material, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a composite modified nano-silica acrylate grouting material, which is made by mixing separately packaged component A and component B in a volume ratio of 1:1 to 2. Component A is made from the following raw materials in parts by weight: 22-33 parts of composite acrylate monomer, 6-11 parts of nanocomposite filler, 4-9 parts of modified functional additives, 0.2-0.7 parts of crosslinking agent, 1.2-2.8 parts of accelerator, 0.2-0.5 parts of pH adjuster, and 45-58 parts of deionized water; Component B is made from raw materials comprising the following parts by weight: 1.1-2.3 parts of composite initiator, 0.15-0.4 parts of low-temperature activator, 0.5-1.2 parts of hydrolysis-resistant stabilizer, and 92-103 parts of deionized water; The composite acrylate monomer is composed of calcium acrylate, zinc acrylate and isobutyl methacrylate; the nanocomposite filler is composed of nano-zirconia and nano-montmorillonite.

[0008] In the composite acrylate monomers, the mass ratio of calcium acrylate, zinc acrylate, and isobutyl methacrylate is 3.2:1.3:0.8; in the nanocomposite filler, the mass ratio of nano-zirconia to nano-montmorillonite is 2.1:1. The ternary monomer system introduces Z... 2+ The formation of metal coordination bonds enhances the network structure, while isobutyl methacrylate lowers the polymer's glass transition temperature (Tg), enabling the material to gel and solidify normally in low-temperature environments below -30℃, thus solving the technical problem of low solidification efficiency of existing materials in cold regions; and the specific ratio of "rigid (zirconia)-layered (montmorillonite)" binary filler system forms a dense multi-scale filling structure, effectively suppressing volume shrinkage and controlling the shrinkage rate to below 1.5%.

[0009] The modified functional additive is composed of polyetheramine D230, perfluorooctyl acrylate and polycaprolactone diol; The crosslinking agent is composed of trimethylolpropane triacrylate and polyethylene glycol diacrylate, wherein the molecular weight of polyethylene glycol diacrylate is 500. The accelerator is composed of diethanolamine and zinc formate; The pH adjuster is a 5% (w / w) aqueous solution of lithium hydroxide.

[0010] The combination of polyetheramine D230, perfluorooctyl acrylate, and polycaprolactone diol gives the material excellent corrosion resistance (provided by the perfluorinated groups), water resistance, and flexibility (provided by polycaprolactone diol). The crosslinking agent, a combination of trimethylolpropane triacrylate and PEGDA(500), balances the crosslinking density and network flexibility. The accelerator, a combination of diethanolamine and zinc formate, can synergistically accelerate the decomposition of the initiator and broaden the reaction temperature range. The 5% lithium hydroxide aqueous solution, as a pH adjuster, can gently adjust the pH of the system and avoid local strong alkaline corrosion, thereby improving the overall hydrolysis resistance of the material under high temperature and high humidity conditions.

[0011] In the modified functional additive, the mass ratio of polyetheramine D230, perfluorooctyl acrylate, and polycaprolactone diol is (2-4):(1-2.5):(1-2.5); in the crosslinking agent, the mass ratio of trimethylolpropane triacrylate to polyethylene glycol diacrylate is 1:1.8; and in the accelerator, the mass ratio of diethanolamine to zinc formate is 2.5:1.

[0012] The composite initiator is composed of ammonium persulfate and sodium persulfate; The low-temperature activator is composed of vitamin C and ferrous ammonium sulfate; The hydrolysis-resistant stabilizer is composed of caprolactam and epichlorohydrin.

[0013] The combination of ammonium persulfate and sodium persulfate improves the initiation efficiency and temperature adaptability; the redox system composed of vitamin C and ferrous ammonium sulfate can effectively reduce the reaction activation energy at low temperatures, ensuring that the material can still gel rapidly in an extremely cold environment of -35℃; the anti-hydrolysis stabilizer composed of caprolactam and epichlorohydrin can form a cross-linking protective structure in the polymer network, inhibiting ester bond hydrolysis, thereby solving the technical problem of easy hydrolysis aging and strength reduction of the material in a long-term high humidity environment (≥60℃).

[0014] In the composite initiator, the mass ratio of ammonium persulfate to sodium persulfate is 1.7:1; in the low-temperature activator, the mass ratio of vitamin C to ferrous ammonium sulfate is 1:2.3; and in the anti-hydrolysis stabilizer, the mass ratio of caprolactam to epichlorohydrin is 3:1.

[0015] Secondly, the present invention provides a method for preparing the above-mentioned composite modified nano-silica acrylate grouting material, comprising the following steps: Step 1: Pre-treat the nanocomposite filler; stir the accelerator, crosslinking agent and composite acrylate monomer until they are evenly dissolved, add the pre-treated nanocomposite filler under nitrogen protection and stir; add the modified functional additives in sequence, heat up, adjust the pH value and mature to obtain component A; Step 2: Dissolve the composite initiator in batches; add the low-temperature activator and anti-hydrolysis stabilizer in sequence and stir evenly; add the remaining deionized water to dilute and adjust the pH value to obtain component B; Step 3: Mix the prepared component A with component B to obtain the composite modified nano-silica acrylate grouting material.

[0016] Preferably, in step 1, the pretreated nanocomposite filler is pretreated in the following order: spraying modification treatment with a composite coupling agent, ultrasonic dispersion treatment in deionized water, drying treatment under vacuum conditions, and grinding and sieving treatment.

[0017] More preferably, the composite coupling agent is a mixture of KH-550 and TC-114 in a mass ratio of 1.5:1; the process parameters for the ultrasonic dispersion treatment are: ultrasonic power 320W, frequency 22kHz, dispersion time 35min, and system temperature ≤35℃; the process parameters for the vacuum drying treatment are: temperature 62℃, vacuum degree -0.085MPa, drying time 2.2h, and the moisture content of the dried material is ≤0.3%; the grinding and sieving treatment is to pass through a 250-mesh sieve.

[0018] Preferably, the preparation of the composite acrylate monomer includes heating acrylic acid to 32-34°C, adding a mixed alkaline solution containing calcium and zinc ions dropwise at a rate of 1.2 mL / min for 75 min, continuing the reaction for 32 min after the addition is complete, and controlling the degree of neutralization to 91-94%.

[0019] In step 1, heat to 40~42℃, keep warm for 20~30 minutes, adjust the pH value to 8.2-8.8, and mature at 30~35℃ for 15~20 minutes.

[0020] Preferably, the pretreated nanocomposite filler is added under nitrogen protection, and the mixture is stirred at 900 r / min for 12 min, then at 580 r / min for 23 min; the modified functional additives are added sequentially, the temperature is raised to 42℃ and kept at that temperature for 28 min; the pH is adjusted to 8.2-8.8 with a pH adjuster, and the mixture is aged at 33℃ for 18 min.

[0021] In step 1, the modified functional additives are added in the following order: first, add polyetheramine D230, then add perfluorooctyl acrylate after a 5-minute interval, and then add polycaprolactone diol after another 5-minute interval; in step 2, the composite initiator is added and dissolved in batches in the following manner: it is added in 3 batches, with a 4-minute interval between each batch, and the amount added in each batch does not exceed 1 / 3 of the total mass of the composite initiator; in the step of adjusting the pH to 2.2-2.8 with sulfuric acid, the mass concentration of sulfuric acid is 3%; in step 3, the volume ratio of component A to component B is 1:1~2.

[0022] Preferably, in step 3, the volume ratio of component A to component B is 1:1.1.

[0023] Thirdly, the present invention provides the application of the above-mentioned composite modified nano-silicon acrylate grouting material in the preparation of seepage prevention and plugging materials for underground structures.

[0024] Preferably, the application of the underground structure seepage prevention and plugging material in grouting construction under extreme environments includes low temperature environments below -35℃ or high temperature and high humidity environments above 60℃.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The composite modified nano-silica acrylate grouting material provided by this invention, through the synergistic effect of the overall formula, achieves stable construction performance of the grouting material within a wide volume ratio mixing range for the first time, solving the bottleneck of "outstanding single performance and unbalanced multiple performances" in the prior art, and laying the material foundation for achieving comprehensive performance of low viscosity (≤40mPa·s), high strength (≥7MPa), and low shrinkage (≤1.5%) in the future.

[0026] The preparation method provided by this invention, through specific steps of "sequentially dissolving the promoter, crosslinking agent, and monomer → adding pretreated filler under nitrogen protection → sequentially adding functional additives → adjusting pH and aging by heating", and the specific order of "dissolving the initiator in batches → sequentially adding the activator and stabilizer → diluting and adjusting pH" in component B, ensures that each component can fully react and be uniformly dispersed, solves the process problems of easy agglomeration and poor batch stability of nanofillers, and lays the foundation for industrial production.

[0027] The grouting material provided by this invention can simultaneously meet the following stringent requirements in underground engineering applications: low viscosity (≤38mPa·s) allows it to penetrate microcracks smaller than 0.08mm; high strength (≥7MPa) and low shrinkage (≤1.5%) ensure long-term sealing after plugging; wide temperature range adaptability from -35℃ to 85℃ allows it to be used in extremely cold regions (such as tunnels in permafrost areas) and high temperature and humidity environments (such as geothermal areas or chemical pipeline corridors); excellent resistance to acid, alkali and salt corrosion (mass change rate ≤±1.5% under pH 1-13 environment) makes it suitable for highly corrosive media environments such as chemical pipeline corridors and marine engineering, achieving true "multi-purpose use of one material" and breaking through the limitation of existing materials that can only adapt to a single harsh environment. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] The composite modified nano-silica acrylate grouting material of this invention consists of separately packaged component A and component B, which are mixed at a volume ratio of 1:1 to 2 during construction. Component A is the main agent phase, providing core mechanical and environmental resistance properties; component B is the initiating catalytic phase, ensuring reaction efficiency and storage stability. The specific formulations, preparation methods, and synergistic effects of components A and B are described in detail below through specific embodiments.

[0031] In the following embodiments, all raw materials used are industrial-grade products and meet the following indicators. Unless otherwise specified, the raw materials, testing methods and equipment are conventionally selected in the art.

[0032] Calcium acrylate: Particle size ≤ 8 μm, purity ≥ 99.2%, water solubility ≥ 18 g / 100 mL (25℃).

[0033] Zinc acrylate: Particle size ≤12μm, purity ≥98.8%, moisture ≤0.3%.

[0034] Isobutyl methacrylate: purity ≥99.5%, moisture ≤0.1%, refractive index 1.435-1.438 (20℃).

[0035] Nano-zirconia: Particle size 15-25nm, specific surface area ≥180m² 2 / g, purity ≥99.6%, monoclinic phase, surface hydroxyl content ≥2.2 hydroxyl groups / nm 2 .

[0036] Nano-montmorillonite: Sodium-based, cation exchange capacity ≥100meq / 100g, particle size ≤30nm, moisture ≤1.2%.

[0037] Polyetheramine D230: molecular weight 230±10, amine value 470-500 mg KOH / g, moisture ≤0.1%.

[0038] Perfluorooctyl acrylate: Fluorine content ≥62%, purity ≥98%, moisture ≤0.15%.

[0039] Polycaprolactone diol: molecular weight 1000±50, hydroxyl value 110-120 mg KOH / g, moisture ≤0.08%.

[0040] Trimethylolpropane triacrylate: purity ≥98.5%, moisture ≤0.1%, viscosity 150-200 mPa·s (25℃).

[0041] Polyethylene glycol diacrylate (PEGDA, molecular weight 500): molecular weight 490-510, purity ≥98%, moisture ≤0.1%.

[0042] Diethanolamine: purity ≥99%, moisture ≤0.1%, boiling point 268℃.

[0043] Zinc formate: particle size ≤15μm, purity ≥98.5%, moisture ≤0.3%.

[0044] Lithium hydroxide: purity ≥98%, moisture ≤0.5%, used to prepare 5% aqueous solution as a pH adjuster.

[0045] Ammonium persulfate: purity ≥98.5%, active oxygen content ≥6.9%, moisture ≤0.2%.

[0046] Sodium persulfate: purity ≥98%, active oxygen content ≥6.5%, moisture ≤0.3%.

[0047] Vitamin C: Food grade, purity ≥99%, melting point 190-192℃, moisture ≤0.5%.

[0048] Ferrous ammonium sulfate: purity ≥99%, Fe 2+ Content ≥14%, moisture ≤0.3%.

[0049] Caprolactam: purity ≥99.5%, melting point 68-70℃, moisture ≤0.1%.

[0050] Epichlorohydrin: purity ≥99%, boiling point 116-118℃, moisture ≤0.1%.

[0051] Deionized water: conductivity ≤8μS / cm, total organic carbon (TOC) ≤4mg / L, total hardness ≤3mg / L.

[0052] I. Pretreatment of Nanocomposite Fillers To fundamentally address the agglomeration problem of nanofillers and ensure their nanoscale dispersion in the polymer matrix, the nanocomposite fillers in all examples and comparative examples were pretreated according to the following steps, unless otherwise stated: Ingredients: Accurately weigh nano-zirconia and nano-montmorillonite according to the designed ratio, with a total mass error of ±0.02 parts. Weigh 4.2% of the total mass of the mixed packing material as a composite coupling agent, which is a mixture of KH-550 and TC-114 at a mass ratio of 1.5:1, and dilute with anhydrous ethanol to a concentration of 10%. Also prepare 15% of the total mass of the mixed packing material as deionized water.

[0053] Preliminary mixing: The weighed nano-zirconia and nano-montmorillonite are added to a high-speed mixer and mixed at 850 r / min for 12 min to achieve preliminary homogenization.

[0054] Coupling agent modification: Under stirring at 500 r / min, the diluted composite coupling agent solution was slowly sprayed into the mixed filler at a rate of 0.8 mL / min. After spraying, stirring was continued for 8 min to ensure uniform coating of the coupling agent.

[0055] Ultrasonic dispersion: Transfer the coated filler to an ultrasonic disperser, add the deionized water prepared in step 1, set the ultrasonic power to 320W and the frequency to 22kHz, disperse for 35 minutes, and control the system temperature to ≤35℃ during the process by circulating water cooling.

[0056] Drying treatment: The dispersed slurry was transferred to a vacuum drying oven and dried at 62℃ and -0.085MPa for 2.2h until the moisture content of the material was ≤0.3% (detected by a Karl Fischer moisture analyzer).

[0057] Post-processing: The dried material is ground by a high-speed pulverizer and passed through a 250-mesh stainless steel sieve. The undersize material is collected. The particle size distribution is measured using a laser particle size analyzer. The particle size distribution must be within 18-42nm with a deviation of ≤4.5%. Otherwise, ultrasonic dispersion treatment is repeated.

[0058] II. Preparation of Complex Acrylate Monomers To ensure the purity and reactivity of the monomers, all composite acrylate monomers in the examples and comparative examples were prepared according to the following steps, unless otherwise stated: Raw material pretreatment: Add acrylic acid to the reactor and heat to 33±1℃. Mix calcium hydroxide and zinc hydroxide according to the ratio of the corresponding metal ions in the composite acrylate monomer, add deionized water to prepare a 25% (w / w) mixed aqueous solution, stir evenly and let stand for 10 min to remove insoluble matter.

[0059] Neutralization reaction: Under stirring at 320 r / min, the mixed aqueous solution was added dropwise to acrylic acid at a rate of 1.2 mL / min using a metering pump over a period of 75 min. The temperature was controlled at 32-34 °C using a jacket cooling system.

[0060] Aging reaction: After the addition is complete, continue stirring for 32 minutes. During this period, check the pH value of the system every 8 minutes to ensure that it is stable at 7.6-8.3.

[0061] Purity control: The degree of neutralization should be determined by acid-base titration and controlled between 91% and 94%. If the degree of neutralization does not meet the standard, add a small amount of mixed aqueous solution or acrylic acid to adjust it.

[0062] Filtration and storage: The prepared composite acrylate monomer is filtered through a 0.45μm inorganic ceramic filter membrane. The transmittance of the filtrate is ≥97%. Then it is transferred to a sealed storage tank under nitrogen protection and stored at 25℃. The shelf life is no more than 7 days.

[0063] III. Common Preparation Procedures for Component A and Component B The preparation of components A and B in each embodiment follows the general steps described below, and the specific formulation amounts are described in each embodiment.

[0064] (I) Preparation steps of component A Equipment and raw material preparation: Prepare a 500 L double-walled glass reactor (with jacketed temperature control, anchor stirrer, and temperature sensor with an accuracy of ±0.5℃). Heat each component A raw material in the prescribed amount at 25℃ for 30 minutes before use.

[0065] Preparation of the base solution: Add 42% of the formulated amount of deionized water to the reactor, start stirring at 550 rpm for 5 minutes. Add the accelerator and crosslinking agent sequentially, stirring for 6 minutes after each addition. Finally, add the composite acrylate monomer and continue stirring for 18 minutes, maintaining the system temperature at 28-32℃ to obtain a homogeneous base solution.

[0066] Packing material dispersion and compounding: With nitrogen protection enabled (flow rate 5 L / min), the pretreated nanocomposite packing material is slowly added at a rate of 0.8 parts / min. First, the stirring speed is increased to 900 r / min for high-speed dispersion for 12 min; then the speed is reduced to 580 r / min for low-speed stirring for 23 min, maintaining the temperature at 30-34℃.

[0067] Functional additive compounding: Maintain a stirring speed of 520 r / min, and add the modified functional additives in the following order: "polyetheramine D230 → perfluorooctyl acrylate → polycaprolactone diol", with a 5-min interval between each additive. After the addition is complete, raise the temperature to 42℃ and maintain the reaction temperature for 28 min. During this period, briefly increase the stirring speed to 650 r / min every 7 min and maintain it for 30 s.

[0068] pH Adjustment and Aging: Lower the system temperature to 33℃, and add 5% lithium hydroxide aqueous solution dropwise at a rate of 0.3 mL / min, monitoring the pH value in real time until the pH stabilizes at 8.2-8.8. Maintain the temperature at 33℃ and age for 18 min, stirring at 300 r / min for 30 s every 6 min during the aging process. After passing the test (viscosity 52-63 mPa·s at 25℃, pH 8.2-8.8), transfer to a nitrogen-protected sealed container and store at 25℃ away from light.

[0069] (II) Preparation steps of component B Equipment and raw material preparation: Prepare a 300L stainless steel reactor (with jacketed temperature control, paddle stirrer, and transmittance meter). Heat each component of the formula (B) at 25℃ for 20 minutes before use.

[0070] Initiator dissolution: Add 52% of the formula amount of deionized water to the reactor, start stirring at 360 r / min, and control the jacket temperature to 27℃. Add the composite initiator in 3 batches, with an interval of 4 min between each batch. The amount added in each batch should not exceed 1 / 3 of the total mass. After the last addition, continue stirring for 13 min until the system transmittance is ≥96%.

[0071] Adding activator and stabilizer: Keep the stirring speed at 310 r / min and the temperature at 25-29℃, first add the low-temperature activator and stir for 9 min (the turbidity of the system is ≤3 NTU); then add the anti-hydrolysis stabilizer and continue stirring for 11 min.

[0072] Dilution and pH adjustment: Add the remaining deionized water, stir for 6 minutes, and then reduce the stirring speed to 280 rpm. Add 3% sulfuric acid solution dropwise at a rate of 0.2 mL / min to adjust the pH to 2.2-2.8. After passing the test (viscosity 18-24 mPa·s at 25℃, pH 2.2-2.8, transmittance ≥95%), transfer to a brown, light-proof, sealed container and store at 25℃.

[0073] (III) Mixed grouting process The prepared components A and B are measured at a volume ratio of 1:1.1 and fed into a two-component static mixer through a metering pump at an environment of 5-42℃. The mixture is mixed at a speed of 380r / min for 35s. The grouting construction is completed within 5 minutes after mixing, and the grouting pressure is controlled at 0.2-0.4MPa.

[0074] Example 1 This embodiment provides a composite modified nano-silica acrylate grouting material. (I) Formulation composition: Component A (total mass parts 100.7 parts): 24.5 parts composite acrylate monomer (15.2 parts calcium acrylate, 5.8 parts zinc acrylate, 3.5 parts isobutyl methacrylate); 7.2 parts nano-composite filler (4.9 parts nano-zirconia, 2.3 parts nano-montmorillonite); 5.3 parts modified functional additives (2.4 parts polyetheramine D230, 1.4 parts perfluorooctyl acrylate, 1.5 parts polycaprolactone diol); 0.36 parts crosslinking agent; 1.65 parts accelerator; 0.28 parts pH adjuster; 50.7 parts deionized water. Component B (total mass parts 98.77 parts): 1.45 parts composite initiator; 0.22 parts low-temperature activator; 0.72 parts anti-hydrolysis stabilizer; 96.4 parts deionized water.

[0075] (II) Preparation method Prepare components A and B respectively according to the above "General Preparation Procedures for Components A and B".

[0076] (III) Performance Testing Following the above-mentioned "mixed grouting process", components A and B were mixed at a volume ratio of 1:1.1 and then their performance was tested.

[0077] Performance test results: Mixed viscosity at 25℃: 36.2 mPa Initial setting time: 48s; volume shrinkage rate: 1.27%; 28-day compressive strength: 7.4MPa; gelation time at -32℃: 11min20s; strength retention rate after 7 days of immersion in water at 65℃: 91%; mass change rate after 28 days of immersion in acid / alkali solution at pH 1 / 13: ±1.42%; bond strength retention rate after 90 days of immersion in salt solution (3.5% NaCl): 86%; storage stability (protected from light at 25℃): no delamination or polymerization after 12.4 months.

[0078] Example 2 This embodiment provides a composite modified nano-silica acrylate grouting material.

[0079] (a) Formula composition Component A (total mass parts 100.96): Composite acrylate monomers: 27.8 parts (including calcium acrylate 17.1 parts, zinc acrylate 6.4 parts, and isobutyl methacrylate 4.3 parts); Nanocomposite fillers: 8.5 parts (including nano zirconium oxide 5.7 parts and nano montmorillonite 2.8 parts); Modifying functional additives: 6.7 parts (including polyetheramine D230 2.9 parts, perfluorooctyl acrylate 1.8 parts, and polycaprolactone diol 2.0 parts); Crosslinking agent: 0.48 parts (trimethylolpropane triacrylate and PEGDA(500) compounded at a mass ratio of 1:1.8); Accelerator: 2.13 parts (diethanolamine and zinc formate compounded at a mass ratio of 2.5:1); pH adjuster: 0.35 parts (5% lithium hydroxide aqueous solution); Deionized water: 47.2 parts.

[0080] Component B (total mass parts 102.11): Composite initiator: 1.78 parts (ammonium persulfate and sodium persulfate compounded at a mass ratio of 1.7:1); Low-temperature activator: 0.29 parts (vitamin C and ferrous ammonium sulfate compounded at a mass ratio of 1:2.3); Anti-hydrolysis stabilizer: 0.94 parts (caprolactam and epichlorohydrin compounded at a mass ratio of 3:1); Deionized water: 99.1 parts.

[0081] (II) Preparation method Prepare components A and B respectively according to the above "General Preparation Procedures for Components A and B".

[0082] (III) Performance Testing Following the above-mentioned "mixed grouting process", components A and B were mixed and grouted at a volume ratio of 1:1.1, and then performance tests were conducted.

[0083] Performance test results: Mixed viscosity at 25℃: 37.5 mPa Initial setting time: 57s; Volume shrinkage rate: 1.18%; 28-day compressive strength: 7.9MPa; Gel time at -34℃: 12min; Strength retention rate after 7-day immersion in water at 70℃: 89%; Mass change rate after 28-day immersion in acid / alkali solution at pH 1 / 13: ±1.33%; Bond strength retention rate after 90-day immersion in salt solution: 88%; Storage stability: Performance qualified after 12.7 months.

[0084] Example 3 This embodiment provides a composite modified nano-silica acrylate grouting material.

[0085] (a) Formula composition Component A (total mass parts 92.38): 22.3 parts of composite acrylate monomers (14.3 parts of calcium acrylate, 5.2 parts of zinc acrylate, and 3.1 parts of isobutyl methacrylate); 6.3 parts of nanocomposite fillers (4.2 parts of nano-zirconia and 2.1 parts of nano-montmorillonite); 4.4 parts of modified functional additives (2.1 parts of polyetheramine D230, 1.1 parts of perfluorooctyl acrylate, and 1.2 parts of polycaprolactone diol); 0.24 parts of crosslinking agent; 1.32 parts of accelerator; 0.22 parts of pH adjuster; and 57.6 parts of deionized water.

[0086] Component B (total mass parts 94.64): 1.15 parts composite initiator; 0.16 parts low-temperature activator; 0.53 parts hydrolysis stabilizer; 92.8 parts deionized water.

[0087] (II) Preparation method Prepare components A and B respectively according to the above "General Preparation Procedures for Components A and B".

[0088] (III) Performance Testing Following the above-mentioned "mixed grouting process", components A and B were mixed and grouted at a volume ratio of 1:1.1, and then performance tests were conducted.

[0089] Performance test results: Mixed viscosity at 25℃: 33.8 mPa Initial setting time: 72 s; Volume shrinkage rate: 1.39%; 28-day compressive strength: 7.1 MPa; Gel time at -34℃: 9 min 40 s; Strength retention rate after 7-day immersion in water at 70℃: 93%; Mass change rate after 28-day immersion in acid / alkali solution at pH 1 / 13: ±1.48%; Bond strength retention rate after 90-day immersion in salt solution: 83%; Storage stability: Performance qualified after 12.1 months.

[0090] Example 4 This embodiment provides a composite modified nano-silica acrylate grouting material.

[0091] (a) Formula composition Component A (total mass parts 99.72): Composite acrylate monomers: 32.1 parts (including calcium acrylate 19.6 parts, zinc acrylate 7.7 parts, and isobutyl methacrylate 4.8 parts), Nanocomposite fillers: 10.6 parts (including nano zirconium oxide 7.1 parts and nano montmorillonite 3.5 parts), Modifying functional additives: 8.5 parts (including polyetheramine D230 3.7 parts, perfluorooctyl acrylate 2.3 parts, and polycaprolactone diol 2.5 parts), Crosslinking agent: 0.65 parts (trimethylolpropane triacrylate and PEGDA(500) compounded at a mass ratio of 1:1.8), Accelerator: 2.68 parts (diethanolamine and zinc formate compounded at a mass ratio of 2.5:1), pH adjuster: 0.47 parts (5% lithium hydroxide aqueous solution), Deionized water: 45.3 parts.

[0092] Component B (total mass parts 106.02): Composite initiator: 2.21 parts (ammonium persulfate and sodium persulfate compounded at a mass ratio of 1.7:1), Low-temperature activator: 0.37 parts (vitamin C and ferrous ammonium sulfate compounded at a mass ratio of 1:2.3), Anti-hydrolysis stabilizer: 1.14 parts (caprolactam and epichlorohydrin compounded at a mass ratio of 3:1), Deionized water: 102.3 parts.

[0093] (II) Preparation method Prepare components A and B respectively according to the above "General Preparation Procedures for Components A and B".

[0094] (III) Performance Testing Following the above-mentioned "mixed grouting process", components A and B were mixed and grouted at a volume ratio of 1:1.1, and then performance tests were conducted.

[0095] Performance test results: Mixed viscosity at 25℃: 38.7 mPa Initial setting time: 104s, volume shrinkage rate: 1.06%, 28-day compressive strength: 8.6MPa, gelation time at -35℃: 13min10s, strength retention rate after 7-day immersion in water at 80℃: 85%, mass change rate after 28-day immersion in acid / alkali solution at pH 1 / 13: ±1.21%, bond strength retention rate after 90-day immersion in salt solution: 90%, storage stability: stable performance for 12.9 months.

[0096] Example 5 This embodiment provides a composite modified nano-silica acrylate grouting material.

[0097] (a) Formula composition Component A (total mass parts 96.97): 29.4 parts of composite acrylate monomers (18.2 parts of calcium acrylate, 6.9 parts of zinc acrylate, and 4.3 parts of isobutyl methacrylate); 9.2 parts of nanocomposite fillers (6.2 parts of nano-zirconia and 3.0 parts of nano-montmorillonite); 7.1 parts of modified functional additives (3.1 parts of polyetheramine D230, 1.9 parts of perfluorooctyl acrylate, and 2.1 parts of polycaprolactone diol); 0.43 parts of crosslinking agent; 1.94 parts of accelerator; 0.32 parts of pH adjuster; and 48.9 parts of deionized water.

[0098] Component B (total mass parts 100.29): composite initiator 1.63 parts; low temperature activator 0.25 parts; hydrolysis stabilizer 0.81 parts; deionized water 97.6 parts.

[0099] (II) Preparation method Prepare components A and B respectively according to the above "General Preparation Procedures for Components A and B".

[0100] (III) Performance Testing Following the above-mentioned "mixed grouting process", components A and B were mixed and grouted at a volume ratio of 1:1.1, and then performance tests were conducted.

[0101] Performance test results: Mixed viscosity at 25℃: 37.1 mPa Initial setting time: 83s, volume shrinkage rate: 1.22%, 28-day compressive strength: 8.2MPa, gelation time at -33℃: 10min50s, strength retention rate after 7-day immersion in water at 75℃: 87%, mass change rate after 28-day immersion in acid / alkali solution at pH 1 / 13: ±1.29%, bond strength retention rate after 90-day immersion in salt solution: 87%, storage stability: no delamination or failure after 12.5 months.

[0102] V. Comparative Examples To further highlight the synergistic innovation of the specific components and processes of this invention, the following comparative examples are provided. Except for the differences listed in the table below, the raw material sources, pretreatment processes, and preparation methods of the comparative examples are consistent with those of Example 1.

[0103] Comparative Example 1: Single calcium acrylate monomer system The difference from Example 1 is that: a single calcium acrylate (24.5 parts) is used as the monomer, and zinc acrylate and isobutyl methacrylate are not included.

[0104] Comparative Example 2: Single Nano-Zirconium Oxide Filler System The difference from Example 1 is that only nano-zirconia (7.2 parts) is added as a nanofiller, and nano-montmorillonite is not included.

[0105] Comparative Example 3: Component B without low-temperature activator and hydrolysis stabilizer The difference from Example 1 is that no low-temperature activator and anti-hydrolysis stabilizer are added to component B.

[0106] Comparative Example 4: Ultrasonic dispersion pretreatment process omitted The difference from Example 1 is that the "ultrasonic dispersion" step is not performed during the pretreatment of the nanocomposite filler.

[0107] Comparative performance test results Performance tests were performed on Comparative Examples 1-4 using the same method as in Example 1, and the results are as follows:

[0108] VI. Analysis of the effect of the proportion 1. Comparative Example 1 vs. Example 1 When using a single calcium acrylate monomer, the material fails to cure at -32°C for more than 30 minutes, exhibits a volume shrinkage rate as high as 2.85%, and a 28-day compressive strength of only 4.6 MPa. This indicates that the ternary composite monomer system of "calcium acrylate + zinc acrylate + isobutyl methacrylate" in this invention, through the introduction of Zn... 2+ The formation of metal coordination bonds to enhance the network structure, and the reduction of the polymer's glass transition temperature (Tg) by isobutyl methacrylate, are key to achieving a synergistic effect of low shrinkage, high strength, and low-temperature curing.

[0109] 2. Comparative Example 2 vs. Example 1 When nano-zirconia is used as the sole filler, the material's volume shrinkage rate increases to 1.98%, and its compressive strength and corrosion resistance also decrease significantly. This demonstrates that the "rigid-layered" binary composite filler system composed of nano-zirconia and nano-montmorillonite can form a denser multi-scale filling and physical cross-linking network, more effectively inhibiting volume shrinkage and blocking the penetration of corrosive media.

[0110] 3. Comparative Example 3 vs. Example 1 When no low-temperature activator and anti-hydrolysis stabilizer are added to component B, the material cannot cure at -32℃, and its strength retention rate drops sharply to 54% under high temperature and high humidity conditions, with severely deteriorated acid, alkali, and salt corrosion resistance. This indicates that the vitamin C / ferrous ammonium sulfate complex system, as a low-temperature activator, can effectively reduce the activation energy of the redox initiation system, ensuring low-temperature polymerization; while the lactam / epimchlorohydrin complex, as an anti-hydrolysis stabilizer, can form a cross-linked protective structure, which is the decisive component for improving the material's wide temperature range adaptability and long-term durability.

[0111] 4. Comparative Example 4 vs. Example 1 When the ultrasonic dispersion step is omitted in the pretreatment of the filler, severe agglomeration occurs, leading to a dramatic increase in viscosity to 45.6 mPa·s after mixing, a decrease in 28-day strength to 4.2 MPa, and a shortened storage period to 2.9 months. This demonstrates that the combined pretreatment process of "coupling agent modification + high-power ultrasonic dispersion + vacuum drying" in this invention is an indispensable technical means to achieve uniform dispersion of nanofillers in the matrix and ensure low viscosity, high strength, and long-term storage stability of the material.

[0112] A comprehensive comparative analysis of Examples 1-5 and Comparative Examples 1-4 confirms that this invention, through precise screening and synergistic use of specific ternary composite monomer systems, binary nanocomposite filler systems, and multifunctional B-component systems, combined with a unique nanofiller pretreatment and hierarchical dispersion composite process, successfully solves the technical problems existing in the prior art. The grouting material protected by this invention achieves, for the first time in the industry, "low viscosity (33.8–38.7 mPa·s) and low permeability (≤40 mPa)." It exhibits a synergistic combination of multiple properties, including high strength (28-day compressive strength 7.1–8.6 MPa), ultra-low volume shrinkage (1.06%–1.39%), long storage life (≥12 months), and wide temperature range (-35℃ to 85℃, with normal gelation and curing within the wide temperature range; no significant sluggishness in solidification below -30℃; strength retention ≥85% in high-temperature and high-humidity environments above 60℃; and no significant hydrolytic failure). It shows minimal changes in quality and strength after immersion in extreme acidic, alkaline, and high-salt media with pH 1–13, and excellent corrosion resistance and aging resistance. It demonstrates good batch consistency and applicability to construction, meeting the needs of seepage prevention and plugging projects under complex conditions of high humidity, high salinity, high water pressure, and extreme temperature differences, such as subway tunnels, water conservancy hubs, and chemical pipelines. It possesses significant progressive and industrial application value.

[0113] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A composite modified nano-silica acrylate grouting material, characterized in that, It is made by mixing separately packaged component A and component B in a volume ratio of 1:1 to 2; Component A is made from the following raw materials in parts by weight: 22-33 parts of composite acrylate monomer, 6-11 parts of nanocomposite filler, 4-9 parts of modified functional additives, 0.2-0.7 parts of crosslinking agent, 1.2-2.8 parts of accelerator, 0.2-0.5 parts of pH adjuster, and 45-58 parts of deionized water; Component B is made from raw materials comprising the following parts by weight: 1.1-2.3 parts of composite initiator, 0.15-0.4 parts of low-temperature activator, 0.5-1.2 parts of hydrolysis-resistant stabilizer, and 92-103 parts of deionized water; The composite acrylate monomer is composed of calcium acrylate, zinc acrylate and isobutyl methacrylate; the nanocomposite filler is composed of nano-zirconia and nano-montmorillonite.

2. The composite modified nano-silica acrylate grouting material according to claim 1, characterized in that... In the composite acrylate monomer, the mass ratio of calcium acrylate, zinc acrylate and isobutyl methacrylate is 3.2:1.3:0.8; in the nanocomposite filler, the mass ratio of nanozirconium oxide and nano montmorillonite is 2.1:

1.

3. The composite modified nano-silica acrylate grouting material according to claim 1, characterized in that, The modified functional additive is composed of polyetheramine D230, perfluorooctyl acrylate and polycaprolactone diol; The crosslinking agent is composed of trimethylolpropane triacrylate and polyethylene glycol diacrylate, wherein the molecular weight of polyethylene glycol diacrylate is 500. The accelerator is composed of diethanolamine and zinc formate; The pH adjuster is a 5% (w / w) aqueous solution of lithium hydroxide.

4. The composite modified nano-silica acrylate grouting material according to claim 3, characterized in that, In the modified functional additive, the mass ratio of polyetheramine D230, perfluorooctyl acrylate, and polycaprolactone diol is (2-4):(1-2.5):(1-2.5); in the crosslinking agent, the mass ratio of trimethylolpropane triacrylate to polyethylene glycol diacrylate is 1:1.8; and in the accelerator, the mass ratio of diethanolamine to zinc formate is 2.5:

1.

5. The composite modified nano-silica acrylate grouting material according to claim 1, characterized in that, The composite initiator is composed of ammonium persulfate and sodium persulfate; The low-temperature activator is composed of vitamin C and ferrous ammonium sulfate; The hydrolysis-resistant stabilizer is composed of caprolactam and epichlorohydrin.

6. The composite modified nano-silica acrylate grouting material according to claim 5, characterized in that, In the composite initiator, the mass ratio of ammonium persulfate to sodium persulfate is 1.7:1; in the low-temperature activator, the mass ratio of vitamin C to ferrous ammonium sulfate is 1:2.3; and in the anti-hydrolysis stabilizer, the mass ratio of caprolactam to epichlorohydrin is 3:

1.

7. The preparation method of the composite modified nano-silica acrylate grouting material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Pre-treat the nanocomposite filler; stir the accelerator, crosslinking agent and composite acrylate monomer until they are evenly dissolved, add the pre-treated nanocomposite filler under nitrogen protection and stir; add the modified functional additives in sequence, heat up, adjust the pH value and mature to obtain component A; Step 2: Dissolve the composite initiator in batches; add the low-temperature activator and anti-hydrolysis stabilizer in sequence and stir evenly; add the remaining deionized water to dilute and adjust the pH value to obtain component B; Step 3: Mix the prepared component A with component B to obtain the composite modified nano-silica acrylate grouting material.

8. The preparation method of the composite modified nano-silica acrylate grouting material according to claim 7, characterized in that, In step 1, heat to 40~42℃, keep warm for 20~30 minutes, adjust the pH value to 8.2-8.8, and mature at 30~35℃ for 15~20 minutes.

9. The preparation method according to claim 7, characterized in that, In step 1, the modified functional additives are added in the following order: first, add polyetheramine D230, then add perfluorooctyl acrylate after a 5-minute interval, and then add polycaprolactone diol after another 5-minute interval; in step 2, the composite initiator is added and dissolved in batches in the following manner: it is added in 3 batches, with a 4-minute interval between each batch, and the amount added in each batch does not exceed 1 / 3 of the total mass of the composite initiator; in the step of adjusting the pH to 2.2-2.8 with sulfuric acid, the mass concentration of sulfuric acid is 3%; in step 3, the volume ratio of component A to component B is 1:1~2.

10. The application of the composite modified nano-silicon acrylate grouting material according to any one of claims 1-6 in the preparation of seepage prevention and plugging materials for underground structures.

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