Highly durable modified acrylic salt grouting material and preparation method thereof

Abstract

This invention belongs to the field of building materials technology, specifically relating to a highly durable modified acrylate grouting material and its preparation method. The material consists of agent A, agent B, and agent C, and significantly improves durability and overall performance through organic-inorganic hybrid technology. The preparation method includes: reacting a composite silane coupling agent with nano-silica sol under alkaline conditions to form a hybrid grout; then mixing and homogenizing it with an acrylate composite solution and a crosslinking agent to obtain agent A; preparing agent B containing a reducing agent and an accelerator at low temperature; and preparing an ammonium persulfate aqueous solution as agent C; during use, agent B and agent C are mixed to form an activation initiation solution, which is then injected into the crack along with agent A for curing. This invention, by constructing a stable hybrid network structure, effectively resists hydrolysis and chemical erosion, significantly enhances the bonding strength with the concrete substrate, and achieves an optimized balance of rigidity, strength, and flexibility, making it suitable for high-requirement building waterproofing and crack repair projects.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a highly durable modified acrylate grouting material and its preparation method. Background Technology

[0002] Acrylic grouting materials, as a common chemical grouting material, are widely used in waterproofing, leak sealing, and crack repair of building structures. Traditional acrylic grouting materials are mainly based on the polymerization reaction of acrylate monomers, forming a gel-like solidified body in the cracks through a free radical initiation system, thereby achieving the effects of water stopping and reinforcement. However, existing technologies have many shortcomings in practical applications, limiting their long-term performance and reliability.

[0003] 1) Existing materials generally lack long-term durability, especially under humid and hot environments and wet-dry cycles. Traditional acrylate gels, with their carbon-carbon long-chain backbone, possess a certain degree of flexibility, but the ester bonds in their molecular structure are prone to hydrolysis under alkaline or humid and hot conditions, leading to polymer network degradation. This degradation is particularly evident in long-term waterproofing projects for concrete cracks, manifesting as material volume shrinkage, decreased elastic modulus, and gradual loss of sealing performance, ultimately resulting in recurring leaks. After using traditional acrylate materials for leak sealing, a significant performance decline occurs within one to two years.

[0004] 2) The interfacial bonding performance between existing materials and concrete substrates needs improvement. Traditional formulations lack effective interfacial reinforcement mechanisms, and the bond between acrylate gels and concrete mainly relies on physical adhesion and limited hydrogen bonding, resulting in limited bond strength. When concrete cracks undergo minor deformation due to temperature changes or loads, this relatively weak interfacial bond is prone to peeling, forming new seepage channels. This problem is particularly prominent in the treatment of dynamic or active cracks.

[0005] 3) There is a contradiction between the mechanical properties and durability of existing materials. To improve the strength and durability of materials, the conventional approach is to increase the crosslinking density or introduce a rigid structure. However, this will increase the brittleness of the material and make it prone to fracture during deformation. On the other hand, the pursuit of flexibility often comes at the cost of sacrificing long-term durability. This imbalance in performance limits the application of traditional acrylate grouting materials in important projects.

[0006] 4) The composition design of existing materials is relatively simple and lacks comprehensive performance optimization for complex use environments. Most commercial products still use basic formulations and have insufficient control over the microstructure of materials, which makes it impossible to effectively improve their aging resistance, dimensional stability and interfacial adhesion while maintaining gel properties. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a highly durable modified acrylate grouting material and its preparation method. The modified acrylate grouting material comprises agent A, agent B, and agent C. When using it, agent B and agent C are mixed at a volume ratio of (0.8-1.2):(0.8-1.2), stirred at 300-400 rpm for 15-25 seconds to obtain an activation initiation solution. Then, agent A and the activation initiation solution are injected together into the crack to be treated at a volume ratio of (0.8-1.2):(0.8-1.2).

[0008] The preparation method specifically includes the following steps:

[0009] Step 1: Adjust the pH of deionized water to 8.5-9.0 using a pH adjuster. Under the combined action of stirring at 800-1000 rpm and ultrasound at 300-400W, add the composite silane coupling agent at a rate of 3-4% total mass / min. Under these alkaline conditions, the methoxy groups of silane rapidly hydrolyze to generate silanols, which then undergo preliminary condensation to form oligomeric siloxanes. After reacting at 30-35℃ for 8-12 minutes, add nano-silica sol and continue the reaction for 10-20 minutes to further condense the hydroxyl groups on its surface with the siloxane oligomers, thus obtaining an organic-inorganic hybrid slurry.

[0010] Preferably, the mass ratio of the deionized water, the composite silane coupling agent, and the nano-silica sol is 25:(8-12):(2-4). Most preferably, the composite silane coupling agent comprises cyano-containing 3-cyanopropyltrimethoxysilane and secondary amino-containing N-phenyl-γ-aminopropyltrimethoxysilane, with a mass ratio of (6-7):(3-4); the pH adjuster is triethanolamine; and the nano-silica sol contains 27-33% silica with a silica particle size of 20-30 nm.

[0011] Step 2: Mix the acrylate composite solution, organic-inorganic hybrid slurry, crosslinking agent and stabilizer at a mass ratio of (90-100):(25-35):(1-2):(0.01-0.05), stir at 200-300 rpm for 25-35 min, and then homogenize by circulating at 20-30 MPa 3-4 times to obtain Agent A.

[0012] Preferably, the acrylate composite solution comprises magnesium acrylate, zinc acrylate, sodium acrylate and water in a mass ratio of (35-45):(7-9):(6-8):(50-60).

[0013] Preferably, the crosslinking agent is pentaerythritol triacrylate (PETA).

[0014] Preferably, the stabilizer is hydroquinone or methyl tert-butyl ether.

[0015] Step 3: Cool the deionized water to 5-10℃, then add the accelerator, stir at 100-200 rpm for 10-15 min, then add the reducing agent at a rate of 4-5% of total mass / min, and continue stirring for 10-20 min to obtain Agent B.

[0016] The mass ratio of the reducing agent, the accelerator and the deionized water is (5-10):(10-15):(75-85).

[0017] Preferably, the reducing agent is L-ascorbic acid and the accelerator is triethanolamine.

[0018] Step 4: Mix ammonium persulfate and deionized water at a mass ratio of (15-20):(80-85) and stir until homogeneous to obtain Agent C.

[0019] The specific principles of this invention are as follows:

[0020] Step one achieves molecular-level hybridization through alkaline catalytic hydrolysis and controlled condensation. In an alkaline environment with pH 8.5-9.0, the methoxy group (-OCH3) of the silane coupling agent first hydrolyzes to generate highly reactive silanol (-Si-OH). By controlling the dropping rate and using ultrasonic dispersion, a uniform distribution of silanol concentration is ensured. An 8-12 minute pre-reaction period allows the silanol to initially condense to form oligomeric siloxanes. At this point, nano-silica is added, and its surface hydroxyl groups condense with the oligomeric siloxanes through dehydration condensation to form strong Si-O-Si covalent bonds, constructing a three-dimensional inorganic-organic hybrid network framework with nanoparticles as nodes and siloxanes as connecting arms.

[0021] Triethanolamine (pH adjuster): provides a stable alkaline environment, promotes the hydrolysis reaction of silane coupling agents, and its nitrogen-containing groups can participate in coordination, thus stabilizing auxiliary materials.

[0022] 3-Cyanopropyltrimethoxysilane: The cyano group has a strong polarity and a symmetrical electron cloud structure, which enhances the intermolecular forces through dipole interactions. At the same time, its hydrophobic properties can effectively block the penetration of water molecules and improve the water resistance of the material.

[0023] N-Phenyl-γ-aminopropyltrimethoxysilane: The secondary amino group provides hydrogen bonding sites, enhancing the interaction with the substrate; the benzene ring structure imparts rigidity to the system, synergistically improving the dimensional stability of the material under humid and hot environments.

[0024] Nano-silica sol: As an inorganic reinforcing phase, the silanol groups on its surface react with siloxane oligomers to form strong covalent bonds, constructing rigid nodes in a hybrid network, which significantly improves the mechanical strength and thermal stability of the material.

[0025] Step two involves high-pressure cyclic homogenization to achieve uniform dispersion and initial cross-linking of the components at the molecular level. Metal ions in the acrylate composite solution coordinate with the active groups in the hybrid slurry, while under mechanical shear force, the cross-linking agent begins to form preliminary connections with the acrylate molecular chains, laying the foundation for the subsequent curing process.

[0026] Magnesium acrylate: Magnesium ions form high-energy ionic bonds with carboxyl groups, constructing a main cross-linked network that endows the material with basic mechanical strength and stability.

[0027] Zinc acrylate: Zinc ions have unique coordination ability, which not only participates in the formation of polymer networks, but also reacts with Ca(OH)2 in cementitious substrates to form insoluble zincates, significantly enhancing the chemical bond with the concrete interface.

[0028] Sodium acrylate: The dynamic ionic bonds formed by sodium ions can undergo reversible breakage and recombination under stress, which plays a role in toughening and stress buffering, and improves the deformation adaptability of materials.

[0029] PETA (crosslinking agent): As a trifunctional crosslinking agent, it can form a three-dimensional network structure between polymer chains, increase the crosslinking density, and enhance the mechanical properties and solvent resistance of the material.

[0030] Methyl tert-butyl ether (stabilizer): By capturing free radicals, it prevents prepolymerization of materials during storage and transportation, thus maintaining the stability of the components.

[0031] Step three involves preparing the reducing agent system under low-temperature conditions. By controlling the feeding rate and stirring intensity, the reducing agent is ensured to dissolve completely without premature reaction. The low-temperature environment effectively inhibits the self-decomposition of the reducing agent and side reactions with any trace amounts of oxidant, thus ensuring the storage stability of the components.

[0032] L-Ascorbic acid (reducing agent): As a mild reducing agent, it donates electrons in redox initiation systems, activating oxidants to generate free radicals. Its naturally occurring nature makes the system more environmentally friendly, and the reaction byproducts are harmless.

[0033] Triethanolamine (accelerator): It serves as an alkaline component to maintain the pH stability of the system, and can also regulate the reaction rate by coordinating the nitrogen atoms in the molecule with metal ions, thus ensuring the smooth progress of the polymerization process.

[0034] Step four involves preparing an oxidant solution through simple mixing. Ammonium persulfate dissociates into persulfate ions in water, providing oxidizing components for the subsequent redox reaction. The homogeneous solution system ensures the stability of the initiator concentration, thereby guaranteeing the reproducibility of the curing reaction.

[0035] Ammonium persulfate: As a water-soluble oxidant, it decomposes under the action of a reducing agent to generate sulfate free radicals, thereby initiating the polymerization reaction of acrylate monomers. Its decomposition rate is moderate, which is beneficial for controlling the gelation process.

[0036] In this process, agent B and agent C are first mixed to form an activating initiator solution. Upon contact, a redox reaction occurs immediately, generating a large number of free radicals. Then, agent A and the activating initiator solution are injected into the cracks. The free radicals rapidly initiate the polymerization reaction of the acrylate monomers, while the active groups in the hybrid network also participate in crosslinking, forming a solidified body with a three-dimensional network structure. Precise control of the volume ratio ensures a perfect match between the oxidant and reductant stoichiometry, making the polymerization reaction both rapid and complete, avoiding the residue of unreacted monomers.

[0037] The present invention has the following advantages:

[0038] (1) This invention fundamentally improves the hydrolysis resistance and structural stability of materials by constructing an organic-inorganic hybrid network structure. During the preparation process, the composite silane coupling agent and nano-silica sol undergo a controlled hydrolysis-condensation reaction to form a robust Si-O-Si covalent network. This inorganic framework interpenetrates with the acrylate organic polymer, constituting a stable hybrid system. This unique structure enables the material to maintain its complete network structure under long-term humid and hot conditions, effectively resisting hydrolytic degradation. Compared with traditional materials, the grouting material prepared by this invention maintains good elasticity and sealing performance even after undergoing wet-dry cycles and long-term water immersion, significantly extending the service life of waterproofing projects.

[0039] (2) Significantly enhanced interfacial adhesion and adaptability: This invention achieves a stronger chemical bond between the material and the concrete substrate through molecular design. The specially selected N-phenyl-γ-aminopropyltrimethoxysilane not only participates in the construction of the hybrid network, but its secondary amine group can also form a strong hydrogen bond with the concrete surface; while the zinc acrylate component can react with the cement hydration product Ca(OH)2 to form an insoluble zincate, establishing a stable chemical bridge at the material-substrate interface. This multi-layered bonding mechanism ensures a durable and strong bond between the material and the concrete, and even when minor deformation occurs in cracks, the interfacial area remains intact, effectively preventing delamination and leakage.

[0040] (3) Optimizing the balance of mechanical properties and stress adaptability: This invention achieves the best balance of material rigidity, strength and flexibility through the synergistic combination of multiple acrylates and hybrid structure design. Magnesium acrylate constructs a high-strength main cross-linked network, providing necessary mechanical support; sodium acrylate imparts good deformability and stress buffering properties to the material through dynamic ionic bonds. This multi-component synergistic material system can adapt to the dynamic changes of cracks while maintaining sufficient strength, and is particularly suitable for dealing with active cracks caused by temperature stress and load changes.

[0041] (4) This invention employs a unique preparation process, including precisely controlled pH environment, ultrasonic-assisted dispersion, and high-pressure cyclic homogenization, to ensure uniform dispersion and full reaction of each component at the molecular level. This precise process control results in a highly consistent microstructure and performance of the final product, avoiding common problems such as component separation, aggregation, and sedimentation in traditional preparation methods, and ensuring the reliability and reproducibility of the material's performance in actual use. Detailed Implementation

[0042] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] Raw material preparation:

[0045] Composite silane coupling agent: 3-cyanopropyltrimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane, in a mass ratio of 6.5:3.5.

[0046] Acrylate composite solution: magnesium acrylate, zinc acrylate, sodium acrylate and water, in a mass ratio of 40:8:7:55.

[0047] Specific preparation method:

[0048] Step 1: Adjust the pH of deionized water to 8.7 with triethanolamine. Under the combined action of stirring at 900 rpm and ultrasound at 350 W, add the composite silane coupling agent at a rate of 3.5% total mass / min. React at 32℃ for 10 min, then add nano silica sol (silica content 30%, silica particle size 20-30 nm), and continue the reaction for 15 min to obtain organic-inorganic hybrid slurry.

[0049] The mass ratio of the deionized water, the composite silane coupling agent, and the nano silica sol is 25:10:3.

[0050] Step 2: Mix the acrylate composite solution, organic-inorganic hybrid slurry, PETA and methyl tert-butyl ether at a mass ratio of 95:30:1.5:0.03, stir at 250 rpm for 30 min, and then homogenize at 25 MPa three times to obtain Agent A.

[0051] Step 3: Cool the deionized water to 5-10℃, then add triethanolamine, stir at 150 rpm for 12 min, then add L-ascorbic acid at a rate of 4.5% total mass / min, and continue stirring for 15 min to obtain Agent B.

[0052] The mass ratio of L-ascorbic acid, triethanolamine, and deionized water is 8:13:80.

[0053] Step 4: Mix ammonium persulfate and deionized water at a mass ratio of 18:83 and stir until homogeneous to obtain Agent C.

[0054] Instructions for use: Mix agent B and agent C at a volume ratio of 1:1 and stir at 350 rpm for 20 seconds to obtain an activation initiation solution. Then, inject agent A and the activation initiation solution together at a volume ratio of 1:1 into the crack to be treated.

[0055] Experimental Example 1

[0056] 1) Experimental Grouping

[0057] Experimental group: Modified acrylate grouting material prepared in Example 1.

[0058] Control group: Acrylic grouting material purchased from Guangdong Shuanghong Waterproof and Thermal Insulation Engineering Co., Ltd.

[0059] 2) Performance testing methods and procedures

[0060] Damp heat aging test: The cured standard cubic specimen (20mm×20mm×20mm) was placed in a constant temperature and humidity test chamber, and the conditions were set at 85℃ and 85% relative humidity for 30 days. After the period, it was removed and cooled to room temperature. The mass of the specimen before and after aging was weighed and the mass change rate was calculated; the compressive strength was tested using a universal testing machine and the strength retention rate was calculated; the volumetric dimensions were measured using a digital caliper and the volume change rate was calculated.

[0061] Chemical resistance test: Standard cubic specimens were completely immersed in 5% H2SO4 solution and 5% NaOH solution respectively for 30 days at room temperature. After immersion, the specimens were removed, rinsed with deionized water, dried, weighed, and the mass loss rate was calculated; their compressive strength was tested and the strength loss rate was calculated.

[0062] Bond strength test: According to standard GB / T 16777-2008, the uncured grout was applied to a cleaned concrete substrate (strength grade C30). After curing for 7 days, tensile bond strength was tested using a universal testing machine. The maximum tensile force at specimen failure was recorded, and the tensile bond strength (MPa) was calculated.

[0063] Bending performance test: The grout was poured into standard long strip specimens (80mm×10mm×4mm). After curing for 7 days, a three-point bending test was performed using a universal testing machine with a span of 60mm. The maximum load at which the specimen broke was recorded, and the bending strength (MPa) was calculated. The gauge length elongation at which the specimen broke was recorded, and the elongation at break (%) was calculated.

[0064] Crack resistance test (dynamic joint cycle test): Grout is filled into a concrete joint simulation device with a preset crack width of 0.3 mm. After it has completely cured, the device is fixed on a fatigue testing machine, and periodic reciprocating motion with an amplitude of ±0.5 mm and a frequency of 1 Hz is applied. The test is continued and observed, and the number of cycles required for visible cracks to appear on the surface or inside the grout is recorded.

[0065] Apparent density test: The apparent density of the cured regular specimens was measured using the water displacement method, a precision electronic balance and a density measuring kit.

[0066] Water absorption test: After drying the specimen to constant weight, weigh it (M1), then immerse it in deionized water for 24 hours. After taking it out, wipe off the surface moisture with a damp towel and weigh it immediately (M2). Calculate the water absorption rate.

[0067] Table 1 Comparison of Durability Test Results

[0068]

[0069] Table 2 Comparison of Bond Strength and Flexibility Test Results

[0070]

[0071] Table 3 Comparison of Tightness Test Results

[0072]

[0073] As shown in Tables 1-3, the modified acrylate grouting material prepared in Example 1 exhibits extremely low mass and volume changes and extremely high strength retention under harsh humid heat aging and chemical corrosion environments, proving that its organic-inorganic hybrid network and stable polymer structure can effectively resist environmental degradation. The modified acrylate grouting material prepared in Example 1 significantly improves bond strength, ensuring a strong bond with the substrate. Simultaneously, high flexural strength and elongation at break indicate that the material possesses both high strength and good flexibility, adapting to matrix deformation without easily cracking, a point fully demonstrated in the dynamic crack resistance cycles far exceeding those of the comparative example. The modified acrylate grouting material prepared in Example 1 has a higher apparent density and lower water absorption rate, proving its more compact structure and ensuring excellent impermeability and overall mechanical properties.

[0074] In summary, the high-durability modified acrylate grouting material provided by this invention is significantly superior to traditional products in key performance indicators, and is particularly suitable for construction engineering fields with extremely high requirements for durability, adhesion and crack resistance.

[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for producing a highly durable modified acrylate grout material, characterized by, Includes the following steps: Step 1: Adjust the pH of deionized water to 8.5-9.0 with a pH adjuster. Under the combined action of stirring and ultrasound, add the composite silane coupling agent at a rate of 3-4% total mass / min. React at 30-35℃ for 8-12 minutes, then add nano silica sol and continue the reaction for 10-20 minutes to obtain organic-inorganic hybrid slurry. The mass ratio of the deionized water, the composite silane coupling agent and the nano silica sol is 25:(8-12):(2-4); Step 2: Mix the acrylate composite solution, organic-inorganic hybrid slurry, crosslinking agent and stabilizer at a mass ratio of (90-100):(25-35):(1-2):(0.01-0.05), and then homogenize under high pressure for 3-4 times to obtain Agent A; Step 3: Cool the deionized water to 5-10℃, then add the accelerator, stir, and then add the reducing agent at a rate of 4-5% of total mass / min, continue stirring, and obtain Agent B; The mass ratio of the reducing agent, the accelerator and the deionized water is (5-10):(10-15):(75-85); Step 4: Mix ammonium persulfate and deionized water at a mass ratio of (15-20):(80-85), stir well, and obtain agent C; The composite silane coupling agent comprises 3-cyanopropyltrimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane in a mass ratio of (6-7):(3-4); The acrylate composite solution comprises magnesium acrylate, zinc acrylate, sodium acrylate and water in a mass ratio of (35-45):(7-9):(6-8):(50-60).

2. The method for preparing a high-durability modified acrylate grouting material according to claim 1, characterized in that, The pH adjuster mentioned in step one is triethanolamine.

3. The method for preparing a high-durability modified acrylate grouting material according to claim 1, characterized in that, The crosslinking agent mentioned in step two is PETA.

4. The method for preparing a high-durability modified acrylate grouting material according to claim 1, characterized in that, The stabilizer mentioned in step two is hydroquinone or methyl tert-butyl ether.

5. The method for preparing a high-durability modified acrylate grouting material according to claim 1, characterized in that, The reducing agent mentioned in step three is L-ascorbic acid.

6. The method for preparing a high-durability modified acrylate grouting material according to claim 1, characterized in that, The accelerator mentioned in step three is triethanolamine.

7. The modified acrylate grouting material prepared by the method according to any one of claims 1-6.

8. The method of using the modified acrylic salt grout material of claim 7, wherein, Mix agent B and agent C at a volume ratio of (0.8-1.2):(0.8-1.2) to obtain an activation initiation solution. Then, inject agent A and the activation initiation solution together at a volume ratio of (0.8-1.2):(0.8-1.2) into the crack to be treated.