Epoxy grouting material with high wet adhesion and preparation method thereof

Abstract

This invention relates to the field of epoxy grouting materials technology. Addressing the problem that epoxy grouting materials used in humid environments such as rail transit experience a decline in adhesion and poor stability over time, this invention specifically discloses a high-humidity-adhesion epoxy grouting material and its preparation method. The high-humidity-adhesion epoxy grouting material comprises component A and component B, mixed in a mass ratio of 1-1.5:0.8-1.2. Component A, by mass fraction, comprises 85-95 wt% catechol-modified epoxy resin, 2-10 wt% aminated graphene oxide, and 5-12 wt% diluent; component B comprises 80-95 wt% amine curing agent, 3-15 wt% hydrophobic modified filler, 3-8 wt% expanded vermiculite, and 1-3 wt% dispersant. This invention uses catechol compounds to modify epoxy resin, constructing catechol groups in the epoxy resin matrix to improve the bonding strength and applicability of epoxy grouting materials in humid environments. The resulting epoxy grouting material has excellent wet bonding performance.

Description

Technical Field

[0001] This invention relates to the field of epoxy grouting materials technology, and more specifically, to an epoxy grouting material with high moisture adhesion and its preparation method. Background Technology

[0002] Grouting refers to the process in construction engineering where certain curable grouts are injected into cracks or pores in rock and soil foundations using appropriate methods. Through replacement, filling, and compression, the mechanical and other properties of the soil are improved. In today's booming infrastructure construction, grouting technology, as a key means of ensuring project quality and safety, is widely used in various engineering projects. From foundation reinforcement of high-rise buildings to tunnel lining for underground rail transit, from dam seepage prevention in large water conservancy projects to crack repair of highway bridges, the performance of grouting materials directly affects the stability, durability, and service life of a project. Epoxy grouting materials, with their excellent bonding properties, mechanical properties, and durability, play a vital role in the field of civil engineering.

[0003] For example, patent CN116285301A provides a non-shrinkage silicone-modified polyurethane epoxy resin grouting material for sealing tunnel lining leakage and its preparation method. The grouting material is made of the following components by weight: 50-70 parts of silicone-modified polyurethane prepolymer, 30-50 parts of modified epoxy resin, 20-50 parts of modified curing agent, and 10 parts of initiator. The silicone-modified polyurethane prepolymer is obtained by condensation of polyurethane prepolymer, amino-terminated epoxy oligomer, and organosilane containing terminal chloride, wherein the mass ratio of polyurethane prepolymer, amino-terminated epoxy oligomer, and organosilane containing terminal chloride is 100:10-30:1-10. The modified epoxy resin is the product of the reaction of methyl methacrylate and epoxy resin, wherein the mass ratio of methyl methacrylate and epoxy resin is 1-0.5:1.

[0004] However, existing epoxy grouting materials have two main problems when exposed to humid environments: First, slow curing at low temperatures. Curing temperature has a decisive impact on the performance of epoxy grouting materials. In low-temperature environments, the curing process and final performance are significantly limited. For example, epoxy-amine grouting systems require approximately 24-48 hours to fully cure at room temperature (25°C), while when the ambient temperature drops to 5°C, it takes 7-14 days or even longer to fully cure. Second, decreased bonding performance. In environments with relative humidity exceeding 90%, the bonding strength of existing epoxy grouting materials may decrease by 30% to 50% within six months. This not only seriously threatens the integrity and stability of the structure but also greatly shortens the service life of the project, leading to a significant increase in subsequent maintenance costs and reduced safety performance. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of declining bonding performance and poor stability of epoxy grouting materials used in humid environments such as rail transit over time.

[0006] This invention is achieved through the following technical solution: This invention provides a highly moisture-adhesive epoxy grouting material comprising component A and component B mixed in a mass ratio of 1-1.5:0.8-1.2; wherein, by mass fraction, component A comprises 85-95 wt% catechol-modified epoxy resin, 2-10 wt% aminated graphene oxide, and 5-12 wt% diluent, and component B comprises 80-95 wt% amine curing agent, 3-15 wt% hydrophobic modified filler, 3-8 wt% expanded vermiculite, and 1-3 wt% dispersant.

[0007] Preferably, the method for preparing the catechol-modified epoxy resin includes the following steps: A1.1 Take catechol, add potassium carbonate, stir and mix, then add 3-chloropropene dropwise, react for 8-12 hours to obtain the first step product; A1.2 Reheat to 200℃ and react again for 12-24 hours to obtain the product of the second step; A1.3 Take the product from the second step, dissolve it in a solvent, add m-chloroperoxybenzoic acid, heat to 40°C, and react for 48 hours to obtain the catechol-modified epoxy resin.

[0008] Preferably, the preparation method of the amino-based graphene oxide includes the following steps: A2.1 Take graphene oxide, 3-aminopropyltriethoxysilane and ethanol-water mixture respectively; A2.2 Graphene oxide was dispersed in an ethanol-water mixture, and then 3-aminopropyltriethoxysilane was added. The mixture was stirred and reacted in an oil bath at 60°C, and then washed and dried to obtain the amino-based graphene oxide.

[0009] Preferably, the preparation method of material A includes the following steps: (1) Add the amino-based graphene oxide to the diluent and disperse it by ultrasonication to obtain a dispersion; (2) Add the dispersion to the catechol-modified epoxy resin, heat to 40-60℃, stir and react to obtain the A material.

[0010] Preferably, the preparation method of the hydrophobic modified filler includes the following steps: B1.1 By mass, take 10 parts of nano-calcium carbonate, 0.5-0.8 parts of stearic acid, 5-8 parts of anhydrous ethanol, and 2-3 parts of deionized water respectively; B1.2 Stearic acid was placed in anhydrous ethanol and heated to dissolve. Then, nano-calcium carbonate was added, and deionized water was added dropwise until the pH value was 7.0-8.0. The mixture was heated and stirred to react. After cooling to room temperature, it was washed and dried to obtain the hydrophobic modified filler.

[0011] Preferably, the method for preparing the expanded vermiculite includes the following steps: B2.1 Take vermiculite ore, crush it, sieve out particles with a diameter ≤75μm, and calcine it at 750-850℃ for 1-5min to obtain vermiculite; B2.2 Take 80-120 parts by weight of vermiculite, 3-5 parts by weight of silane coupling agent and ethanol-water solution, and set aside.

[0012] B2.3 Add the silane coupling agent to an ethanol-water solution, adjust the pH to 4.0-5.0, and carry out a hydrolysis reaction; then add vermiculite, heat and stir, and carry out the reaction; after the reaction is completed, filter, wash and dry to obtain the expanded vermiculite.

[0013] Preferably, the preparation method of material B includes the following steps: (1) Take an amine curing agent, add a hydrophobic modified filler under stirring, then add a dispersant, heat and stir to react and obtain a preliminary mixture; (2) The initial mixture was stirred at 7000-9000 rpm and expanded vermiculite was added. After being dispersed evenly, it was ground until the particle size was ≤1μm and then degassed under vacuum to obtain material B. The present invention also provides a method for preparing the above-mentioned epoxy grouting material with high moisture adhesion, comprising the following steps: S1 Take material A, then add material B to material A at a uniform rate, and add material B over a period of 3-8 minutes to obtain the initial mixture; S2 The initial mixture is first stirred at 40-60 rpm for 3-8 minutes, then stirred at 135-165 rpm for 8-12 minutes, and finally stirred at 280-320 rpm for 1-5 minutes. After standing and maturing, the epoxy grouting material is obtained.

[0014] The technical solution of the present invention has the following beneficial effects: The epoxy grouting material proposed in this invention focuses on the molecular-level structural modification of epoxy resin using catechol compounds. Catechol groups are constructed within the epoxy resin matrix. Although the structure of catechol is very simple, consisting of only a benzene ring with two adjacent hydroxyl groups, it can effectively interact with almost any type of surface, exhibiting excellent underwater adhesion properties. This is because, depending on the properties of the substrate, catechol can bond through different chemical interactions. Furthermore, catechol can spontaneously replace water molecules on the bonding surface and form hydrogen bonds with its surface hydroxyl groups, thereby generating stronger interfacial interactions to enhance wet bonding performance. By constructing a catechol structure, this invention significantly improves the surface bonding ability of the epoxy grouting material. Simultaneously, the phenolic groups in catechol promote low-temperature curing of epoxy resin, improving the bonding strength and applicability of the epoxy grouting material in humid environments. It possesses excellent wet bonding performance, making it particularly suitable for applications such as leakage repair of tunnel segments in rail transit and water-sealing of track bed cracks. Attached Figure Description

[0015] Figure 1 This is a diagram of the etherification reaction process for preparing catechol-modified epoxy resin in this invention. Figure 2 This is a diagram of the thermal rearrangement reaction process for preparing catechol-modified epoxy resin in this invention; Figure 3 This is a diagram of the epoxidation reaction process for preparing catechol-modified epoxy resin in this invention (taking ortho-diallylated catechol as an example).

[0016] Figure 4 This is the infrared spectrum of the product from the first step in Example 1 of the present invention.

[0017] Figure 5 This is a TIC diagram of the product from the first step in Embodiment 1 of the present invention.

[0018] Figure 6 Infrared spectrum of the product from the second step in Example 1 of this invention. Figure 7 This is a TIC diagram of the product from the second step in Embodiment 1 of the present invention.

[0019] Figure 8 This is a TIC diagram of the product from the third step in Embodiment 1 of the present invention.

[0020] Figure 9 This is a high-resolution MS image of the product from the third step in Embodiment 1 of the present invention.

[0021] Figure 10 This is the hydrogen spectrum of the product from the third step in Example 1 of this invention.

[0022] Figure 11This is the carbon spectrum of the product from the third step in Example 1 of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are performed according to conventional conditions or conditions recommended by the manufacturer; where the manufacturers of the instruments, equipment, reagents, or raw materials used are not specified, they are all conventional products that can be purchased commercially.

[0024] This invention provides an epoxy grouting material with high moisture adhesion, comprising component A and component B mixed in a mass ratio of 1-1.5:0.8-1.2; The components, by mass fraction, consist of: component A comprising 85-95 wt% catechol-modified epoxy resin (CT-EP), 2-10 wt% aminated graphene oxide (NH2-GO), and 5-12 wt% diluent; and component B comprising 80-95 wt% amine curing agent, 3-15 wt% hydrophobic modified filler, 3-8 wt% expanded vermiculite, and 1-3 wt% dispersant.

[0025] The amino-based graphene oxide in material A is prepared by the following method: (1) Take 1g of graphene oxide (containing oxygen functional groups with a molecular weight of ≥30%), 5mL of 3-aminopropyltriethoxysilane (APTES), and 50mL of ethanol-water mixture with a volume ratio of 3:1.

[0026] (2) Disperse graphene oxide in an ethanol-water mixture and sonicate for 20-40 min until a uniform colloid is obtained; then add APTES, adjust the pH to 8.0-9.0, place in an oil bath at 50-70℃, and stir for 10-15 h; after the reaction, wash with ethanol 2-5 times, and vacuum centrifuge at 50-70℃ to obtain amino-based graphene oxide (NH2-GO).

[0027] The amounts of each raw material are for illustrative purposes only and for reference. Those skilled in the art can adjust the specific amount of each component based on their relative proportions and dosage relationships.

[0028] The catechol-modified epoxy resin in component A is synthesized through the following three-step reaction process: (1) such as Figure 1 As shown, the etherification reaction is carried out: Catechol and 3-chloropropene were mixed with potassium carbonate and stirred. Then, 3-chloropropene was added dropwise and reacted for 8-12 hours. Under alkaline conditions, an O-alkylation reaction was carried out to produce 2-allyloxyphenol and 1,2-diallyloxybenzene, which are the products of the first step.

[0029] The product obtained at the end of the reaction is a mixture, which needs to be separated and purified to obtain the first-step product. The purification method is as follows: the reaction product is acidified, an organic solvent is added for extraction, the organic phases are combined, washed, dried, and then the organic solvent is removed by rotary evaporation to obtain the first-step product.

[0030] (2) such as Figure 2 As shown, a thermal rearrangement reaction (Claisen Rearrangement) is performed: The 1,2-diallyloxybenzene obtained from the previous reaction undergoes a Claisen thermal rearrangement reaction at a high temperature of 200°C or above for 12-24 hours to generate allylated catechol, which is the product of the second step.

[0031] The product obtained at the end of the reaction is a mixture, which needs to be separated and purified to obtain the product of the second step. The purification method is as follows: the reaction product is alkalized to transfer the product to the aqueous phase, the aqueous phase is acidified, an organic solvent is added for extraction, the organic phases are combined, washed, dried, and then the organic solvent is removed by rotary evaporation to obtain the product of the second step.

[0032] (3) such as Figure 3 As shown, an epoxidation reaction is carried out: The product from the second step was dissolved in a solvent, and then m-chloroperoxybenzoic acid was added. The mixture was heated to 40°C and reacted for 48 hours. The carbon-carbon double bonds in the allylated catechol were epoxidized by m-chloroperoxybenzoic acid, and finally catechol-modified epoxy resin (CT-EP) was obtained.

[0033] The products obtained at the end of the reaction are a mixture, which needs to be separated and purified to obtain the final product. The purification method is as follows: the reaction product is cooled to crystallize, washed, and the organic solvent is removed by rotary evaporation, thus obtaining the product of the third step.

[0034] The epoxidation reaction can occur in the allylated catechols obtained in the second step, which have allyl groups attached at different positions. Figure 3 The example and reference used here is only diallylated catechol.

[0035] The diluent used in material A can be alkylene glycidyl ether (HK-66), or other commonly used diluents may be selected by those skilled in the art.

[0036] In this invention, the preparation method of material A includes the following steps: (1) Add the amino-based graphene oxide to the diluent and ultrasonically disperse it at 250-350W for 15-30 minutes to form a uniform dispersion; (2) The dispersion is slowly and uniformly added to the catechol-modified epoxy resin and magnetically stirred at 40-60℃ with a speed of 300-700 rpm for 0.5-1.5 h to fully combine the aminated graphene oxide with the catechol-modified epoxy resin to obtain material A.

[0037] In component A, the amino groups in NH2-GO form hydrogen bonds with the catechol groups in CT-EP and undergo a curing reaction with the epoxy groups of the epoxy resin. At the same time, the layered structure of graphene oxide can enhance the interfacial mechanical interlocking. Through interfacial synergy, a three-dimensional network structure of "catechol-amino-epoxy" is formed, which can improve wet adhesion and enhance the mechanical strength and water resistance of the material.

[0038] The hydrophobic modified filler in material B uses nano-sized calcium carbonate as the main material, which undergoes surface modification and is incorporated with expanded vermiculite, etc. The specific preparation method is as follows: (1) Take 8-12 parts of nano-calcium carbonate with a particle size of 50-100nm, 0.5-0.8 parts of stearic acid, 5-8 parts of anhydrous ethanol, and 2-3 parts of deionized water by mass. Place the nano-calcium carbonate in an oven at 70-95℃ and dry it for 3-5 hours to remove the surface adsorbed water.

[0039] (2) Dissolve stearic acid in anhydrous ethanol, place it in a water bath at 50-70℃, and stir until fully dissolved; then add nano calcium carbonate, and simultaneously add deionized water until the pH value is adjusted to 7.0-8.0, heat to 70-90℃, stir at 200-500 rpm, and react for 1-3 hours. During this period, stearic acid can coat the surface of the particles through physical adsorption and chemical reaction with the hydroxyl groups on the surface of calcium carbonate to form an ester bond, forming a hydrophobic layer; after the reaction is completed, cool to room temperature, wash with ethanol 2-5 times, centrifuge at 6000-10000 rpm for 5-20 minutes, and then place it in a vacuum dryer at 50-70℃ for 10-15 hours to obtain the hydrophobic modified filler.

[0040] The expanded vermiculite in material B is prepared using the following method: (1) Take vermiculite ore, crush it to 200 mesh, and screen out particles with a particle size ≤75μm; then place it in a muffle furnace at 750-850℃ for calcination for 1-5 minutes, the volume expands to 5-8 times, and a porous layered structure is formed for later use.

[0041] (2) Take 80-120 parts of vermiculite obtained by the above treatment, 3-5 parts of γ-aminopropyltriethoxysilane coupling agent, and 80-120 parts of ethanol-water solution with a volume ratio of 4:1 by mass. Add the γ-aminopropyltriethoxysilane coupling agent to the ethanol-water solution, adjust the pH value to 4.0-5.0 with acetic acid, and hydrolyze for 20-50 min to form silanol. Then add vermiculite and stir magnetically at 50-70℃ for 1-3 h. The hydroxyl groups on the surface of vermiculite can condense with silanol to form silicon-oxygen bonds. After filtration, wash with ethanol and dry at 90-120℃ for 3-5 h to obtain expanded vermiculite.

[0042] Diethylenetriamine (DETA) can be used as the amine curing agent in material B. Other commonly used amine curing agents can also be selected by those skilled in the art.

[0043] The dispersant in material B can be a polycarboxylate dispersant (PC), or other commonly used dispersants can be selected by those skilled in the art.

[0044] In this invention, the preparation method of material B includes the following steps: (1) Add the amine curing agent to the reactor and stir at 300-700 rpm at room temperature. Add the hydrophobic modified filler in 2-5 batches with an interval of 2-5 min between each batch. Then add the dispersant, heat to 35-50℃, and continue stirring for 10-30 min. The amine curing agent and the stearic acid on the surface of the hydrophobic modified filler form a steric hindrance to prevent agglomeration and ensure uniform dispersion, thus obtaining the initial mixed material.

[0045] (2) Place the initial mixed material in a high shear disperser, add expanded vermiculite at a speed of 7000-9000 rpm, and stir and disperse for 5-15 minutes. The layered structure of expanded vermiculite can pierce the soft agglomerates of hydrophobic modified filler. Then grind it with a three-roll mill with a roller gap of 0.05 mm to refine the particle size to ≤1 μm. Then stir it for 3-10 minutes under a vacuum of -0.09 MPa at room temperature of 25℃ to eliminate the bubbles formed during the dispersion process and obtain material B.

[0046] This invention provides a method for preparing the above-mentioned epoxy grouting material, comprising the following steps: At 40-60℃, add component A to the mixer, and then slowly add component B at a uniform rate over a period of 3-8 minutes. Then, stir at 40-60 rpm for 3-8 minutes to ensure full contact between the components. Next, stir at 135-165 rpm for 8-12 minutes to ensure full reaction between the aminated graphene oxide and the amine curing agent. Finally, stir at 280-320 rpm for 1-5 minutes while simultaneously turning on a -0.08 MPa vacuum to remove air bubbles generated during the mixing process. Allow the stirred and reacted material to stand at 40-60℃ for 2 hours to mature, thus obtaining the epoxy grouting material.

[0047] Example 1 Preparation of catechol-modified epoxy resin: (1) Take a 250 mL three-necked flask and equip it with a reflux condenser, thermometer, constant pressure separatory funnel and stirring device. Add 11.01 g 100 mmol catechol and 80 mL dimethylformamide solvent to the three-necked flask in sequence and stir until fully dissolved. Then add 27.64 g 200 mmol potassium carbonate and stir for 3 min. Then add 15.31 g 200 mmol 3-chloropropene dropwise to the three-necked flask through the constant pressure dropping funnel to complete the addition. Heat the reaction system in the three-necked flask to 40 °C and reflux for 8-12 h to obtain the first step product.

[0048] The product obtained at the end of the reaction is a mixture (TIC diagram shown). Figure 5 As shown in the figure, the system needs to be cooled to room temperature. Add an appropriate amount of water and stir until well mixed. Then, acidify the mixture to a pH < 3. Extract the acidified solution with ethyl acetate, combine the organic phases, and wash with saturated sodium chloride solution to remove residual water. After washing, dry the organic phase with an appropriate amount of anhydrous sodium sulfate, filter to remove the desiccant, and concentrate the resulting filtrate under reduced pressure using a rotary evaporator to remove the ethyl acetate solvent, finally obtaining the first-step product. The infrared spectrum of the first-step product is shown in the figure. Figure 4 As shown, the product of the first step was confirmed to be 1,2-diallyloxybenzene.

[0049] (2) Take another 250mL three-necked flask and equip it with a reflux condenser, thermometer, three-way valve and stirring device. First add the product of the first step, then add 100mL of N,N-diethylaniline and stir until fully dissolved. Then place it under nitrogen protection and heat to 200℃ for 12h. During the reaction, keep stirring at 500rpm to obtain the product of the second step.

[0050] The product obtained at the end of the reaction is a mixture (TIC diagram shown). Figure 7 As shown in the figure, the system needs to be cooled to room temperature before adding 2 M sodium hydroxide solution. After standing, the system separates into two layers, with the product mainly present in the lower aqueous phase. The aqueous phase is separated, and hydrochloric acid solution is added dropwise under stirring to adjust to acidity. Subsequently, the acidified aqueous phase is extracted with ethyl acetate, and the organic phase is collected by liquid-liquid extraction. The organic phases are combined and washed three times with saturated sodium chloride solution to remove residual water. The washed organic phase is dried with an appropriate amount of anhydrous sodium sulfate, filtered to remove the drying agent, and the resulting filtrate is passed through a rotary evaporator to remove the ethyl acetate solvent, finally yielding the product of the second step. The infrared spectrum of the product of the second step is shown in the figure. Figure 6 As shown, the product of the second step was determined to be allylated catechol and its positional isomers.

[0051] (3) Take another 100 mL three-necked flask and equip it with a reflux condenser, thermometer, constant pressure separatory funnel and stirring device. First, add 0.19 g of 1 mmol of the second step product, then add 10 mL of dichloromethane and stir at 0 °C until fully dissolved. Weigh 1.96 g of 8 mmol of m-chloroperoxybenzoic acid and dissolve it in 440 mL of dichloromethane. Then, add the dissolved solution dropwise to the above three-necked flask through a constant pressure dropping funnel within 30 min. Keep the temperature of the reaction system in the three-necked flask at 0 °C and stir for 1 h. Then, heat to 40 °C and react for 48 h, stirring at 500 rpm during the reaction. The reaction yields catechol-modified epoxy resin.

[0052] The product obtained when the reaction is complete is a mixture (as shown in the TIC diagram). Figure 8 As shown in the figure, further purification is required. After the reaction is complete, the reaction system is cooled at -5℃ for 6 h, and then the precipitated solid precipitate is removed by filtration. The obtained filtrate is washed successively with 20% sodium sulfite solution, 10% sodium carbonate solution, and saturated sodium chloride solution until the aqueous phase is neutral. The obtained organic phase is subjected to rotary evaporation to remove the dichloromethane solvent, finally yielding the third product. The mass spectrum of the third product is shown in the figure. Figure 9 As shown, the proton and carbon spectra are as follows: Figure 10-11 As shown, the chemical formula of the product can be confirmed as C. 12 H 14 O4Na (i.e., C) 12 H 15 The sodium salt form of O4 has the following structural formula: .

[0053] Example 2 Preparation of amino-based graphene oxide: (1) Add 1.0g of graphene oxide to a 250mL beaker, pour in a mixture of 37.5mL of anhydrous ethanol and 12.5mL of deionized water, stir with a glass rod until the graphene oxide is fully dispersed, place in an ultrasonic instrument, and sonicate at 300W power for 30min until a uniform brownish-yellow colloidal solution is formed.

[0054] (2) Measure 5.0 mL of 3-aminopropyltriethoxysilane using a graduated cylinder and slowly pour it into the above brownish-yellow colloidal solution while stirring. Place the beaker on a magnetic stirrer, set the temperature to 60℃, and stir at 300 rpm for 10 min. Then add 25% ammonia dropwise with a dropper, while using pH paper to test the pH value of the solution and adjust it to about 8.5. Maintain a constant temperature of 60℃ and stir magnetically for 12 h to carry out the reaction.

[0055] (3) After the reaction is completed, the reaction liquid is cooled to room temperature and then transferred to a 100mL centrifuge tube. 50mL of anhydrous ethanol is added and centrifuged at 8000rpm for 10min. The supernatant is discarded and the solid precipitate is washed with anhydrous ethanol and centrifuged 3 times. The solid precipitate is then transferred to a petri dish and placed in a vacuum drying oven. The oven is set to 60℃ and -0.08MPa and dried for 12h to obtain black amino graphene oxide. The oxide is then sealed and stored in the drying oven.

[0056] Example 3 Preparation of hydrophobic modified fillers: (1) Place 100g of nano calcium carbonate in a porcelain boat, put it in an oven, dry it at 80℃ for 4 hours, dry and store it for later use.

[0057] (2) Add 60 mL of anhydrous ethanol to a 250 mL beaker, weigh 6 g of stearic acid and pour it into the ethanol, then place it on a magnetic stirrer and heat it in a 60 °C water bath until the stearic acid is completely dissolved; then add dry nano calcium carbonate, stir evenly, add 20 mL of deionized water, adjust the pH of the solution to about 7.5 with acetic acid, heat to 80 °C, and stir at 300 rpm for 2 h; after the reaction is completed, cool to room temperature and transfer to a centrifuge tube, add 50 mL of anhydrous ethanol, centrifuge at 8000 rpm for 10 min, discard the supernatant, and wash the solid precipitate with anhydrous ethanol and centrifuge a total of 3 times; then transfer the solid precipitate to a petri dish, put it in a vacuum drying oven, set to 60 °C and -0.08 MPa and dry for 12 h to obtain the hydrophobic modified filler.

[0058] Example 4 Preparation of expanded vermiculite: (1) Grind 150g of vermiculite ore in a mortar, pass it through a 200-mesh sieve, and collect particles with a particle size ≤75μm; then spread the sieved vermiculite particles evenly on a porcelain boat, put it into a muffle furnace, calcine at 800℃ for 3min, cool, and set aside.

[0059] (2) Add 32 mL of anhydrous ethanol and 8 mL of deionized water to a 250 mL beaker, then add 4 g of KH-550 coupling agent, add acetic acid to adjust the pH to 4.5, and stir for 30 min; then add 100 g of expanded vermiculite, heat in a 60 °C water bath, and stir magnetically at 300 rpm for 2 h to carry out the reaction; after the reaction is completed, filter, take the solid precipitate, wash it twice with anhydrous ethanol, then transfer it to a watch glass and dry it at 100 °C for 44 h to obtain expanded vermiculite.

[0060] Example 5 Step 1: Prepare Material A (1) Take 90 wt% of the catechol-modified epoxy resin prepared in Example 1, 5 wt% of the aminated graphene oxide prepared in Example 2, 4.5 wt% of alkylene glycidyl ether and 0.5 wt% of KH-550 silane coupling agent by mass fraction, and set aside.

[0061] (2) First, add alkyl glycidyl ether and KH-550 silane coupling agent to a beaker, then place the beaker on a water bath and heat it to 60°C. Stir at 300 rpm for 5 min. Then add amino graphene oxide and sonicate at 4400 W for 30 min to obtain a homogeneous sol.

[0062] (3) Slowly pour the homogeneous sol into the catechol-modified epoxy resin and heat it to 70°C. Use a high-shear emulsifier to disperse it at 12,000 rpm for 20 minutes until the viscosity of the system stabilizes in the range of 800-1000 mPa·s to obtain material A.

[0063] Step 2: Prepare ingredient B (1) Take 85wt% diethylenetriamine, 8wt% hydrophobic modified filler prepared in Example 3, 5wt% expanded vermiculite prepared in Example 4 and 2wt% polycarboxylate dispersant by mass fraction, and set aside.

[0064] (2) First, add diethylenetriamine to the reactor and stir at 500 rpm at room temperature. While stirring, add the hydrophobic modified filler in two batches with a 5-minute interval between each batch. Then add polycarboxylate dispersant, heat to 40°C, and continue stirring for 15 minutes. Then use a high-shear disperser and stir at 8000 rpm. Add expanded vermiculite and continue stirring and dispersing for 10 minutes. Grind with a three-roll mill with a roller gap of 0.05 mm until the particle size is ≤1 μm. Cool to 25°C or below and stir for 5 minutes under a vacuum of -0.09 MPa to degas the material and obtain material B.

[0065] Step 3: Preparation of epoxy grouting material A 5L double planetary mixer was used, and the temperature was controlled at 50℃. First, material A was added, and then material B was added at a uniform speed. The mass ratio of material A to material B was controlled at 1.2:1, and the addition of material B took 5 minutes. After the addition of material B, the mixture was first stirred at a low speed of 50 rpm for 5 minutes, then at a medium speed of 150 rpm for 10 minutes, and then at a high speed of 300 rpm for 3 minutes. At the same time as the high-speed stirring, a vacuum of -0.08 MPa was turned on for degassing. After the mixing was completed, the mixture was placed at 50℃ for 2 hours to mature, and the epoxy grouting material was obtained.

[0066] Example 6 The difference between this embodiment and embodiment 5 is as follows: Step 3: Preparation of epoxy grouting material A 5L double planetary mixer was used, and the temperature was controlled at 50℃. First, material A was added, and then material B was added at a uniform speed. The mass ratio of material A to material B was controlled at 1:1.2, and the feeding time of material B was 3.5 minutes. After the material B was added, the mixture was first stirred at a low speed of 50 rpm for 5 minutes, then at a medium speed of 150 rpm for 10 minutes, and then at a high speed of 300 rpm for 3 minutes. At the same time as the high-speed stirring, a vacuum of -0.08 MPa was turned on for degassing. After the mixing was completed, the mixture was placed at 50℃ for 2 hours to mature, and the epoxy grouting material was obtained.

[0067] Example 7 The difference between this embodiment and embodiment 5 is as follows: A 5L double planetary mixer was used, and the temperature was controlled at 50℃. First, material A was added, and then material B was added at a uniform speed. The mass ratio of material A to material B was controlled at 1.2:1, and the addition of material B took 5 minutes. After the addition of material B, the mixture was first stirred at a low speed of 60 rpm for 3 minutes, then at a medium speed of 150 rpm for 10 minutes, and then at a high speed of 280 rpm for 5 minutes. At the same time as the high-speed stirring, a vacuum of -0.08 MPa was turned on for degassing. After the mixing was completed, the mixture was placed at 50℃ for 2 hours to mature, and the epoxy grouting material was obtained.

[0068] Example 8 The difference between this embodiment and embodiment 5 is as follows: The raw materials for preparing material A include: 85 wt% catechol-modified epoxy resin prepared in Example 1, 2 wt% aminated graphene oxide prepared in Example 2, 12 wt% alkylene glycidyl ether and 1 wt% KH-550 silane coupling agent.

[0069] Example 9 The difference between this embodiment and embodiment 5 is as follows: The raw materials for preparing material B include: 92 wt% diethylenetriamine, 3 wt% hydrophobic modified filler prepared in Example 3, 3 wt% expanded vermiculite prepared in Example 4, and 2 wt% polycarboxylic acid dispersant.

[0070] Comparative Example 1 The difference between this comparative example and Example 5 is that an alicyclic epoxy resin is used instead of the catechol-modified epoxy resin.

[0071] Comparative Example 2 The difference between this comparative example and Comparative Example 1 is that Material A contains only alicyclic epoxy resin, alkylene glycidyl ether, and KH-550 silane coupling agent.

[0072] Comparative Example 3 The difference between this comparative example and Comparative Example 1 is that material B contains only diethylenetriamine and polycarboxylic acid dispersant.

[0073] Test case Referring to the specifications of JC / T 1041-2007 "Epoxy Resin Grouting Materials for Concrete Cracks", the bond strength of the grouting material samples in Examples 5-9 and Comparative Examples 1-3 was tested, and figure-eight shaped cement mortar specimens were prepared (refer to GB / T16777-2008, 7.2.1.4). For dry bonding, the cement mortar blocks were removed from the curing water and left at room temperature for 2 days; for wet bonding, the cement mortar blocks were removed from the curing water, and the free water was wiped away with a cloth before bonding. Before the test, the grout was evenly applied to the fracture surface, with a thickness controlled at 0.5~0.7mm. Depending on the product, it could be applied in one coat or in several coats. After application, the specimens were quickly joined together at the fracture point, secured with rubber clamps, and cured in a test chamber at a temperature of 20±3℃ and a relative humidity of 50%~70% for 28 days.

[0074] Then, tensile bond tests were conducted. The specimens were placed on a tensile testing machine and stretched at a loading rate of 100 N / s. The breaking load was recorded, and the bond strength θ = P / S was calculated. Where P is the breaking load and S is the tensile area. Five parallel tests were performed for each group of samples, and the average value was taken. The results are shown in Table 1. Table 1

[0075] As can be seen, the traditional epoxy grouting materials in Comparative Examples 1 to 3, under dry bonding conditions, still maintain a bond strength close to the Class II standard. However, under wet bonding conditions, the bond strength decreases significantly, by more than one-third compared to the dry bonding strength. Specifically, the wet bonding strength of Comparative Example 2 is close to the minimum limit of the Class I standard, and the wet bonding strength of Comparative Example 3 is even lower than the Class I standard, with a decrease rate of 56.8%. In contrast, the epoxy grouting materials in Examples 5 to 9 maintain stable bond strength even in humid environments, with a decrease of no more than 10% compared to the dry bonding strength.

[0076] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An epoxy grout material with high wet adhesion characterized in that, This includes material A and material B mixed in a mass ratio of 1-1.5:0.8-1.2; By mass fraction, component A comprises 85-95 wt% catechol-modified epoxy resin, 2-10 wt% aminated graphene oxide, and 5-12 wt% diluent; component B comprises 80-95 wt% amine curing agent, 3-15 wt% hydrophobic modified filler, 3-8 wt% expanded vermiculite, and 1-3 wt% dispersant.

2. The epoxy grout material of claim 1, wherein, The preparation method of the catechol-modified epoxy resin includes the following steps: A1.1 Take catechol, add potassium carbonate, stir and mix, then add 3-chloropropene dropwise, react for 8-12 hours to obtain the first step product; A1.2 Reheat to 200℃ and react again for 12-24 hours to obtain the product of the second step; A1.3 Take the product from the second step, dissolve it in a solvent, add m-chloroperoxybenzoic acid, heat to 40°C, and react for 48 hours to obtain the catechol-modified epoxy resin.

3. The epoxy grout material of claim 1, wherein the epoxy grout material has a high wet bondability. The preparation method of the amino-based graphene oxide includes the following steps: A2.1 Take graphene oxide, 3-aminopropyltriethoxysilane and ethanol-water mixture respectively; A2.2 Graphene oxide was dispersed in an ethanol-water mixture, and then 3-aminopropyltriethoxysilane was added. The mixture was stirred and reacted in an oil bath at 60°C, and then washed and dried to obtain the amino-based graphene oxide.

4. The epoxy grouting material with high moisture adhesion according to any one of claims 1 to 3, characterized in that, The preparation method of material A includes the following steps: (1) Add the amino-based graphene oxide to the diluent and disperse it by ultrasonication to obtain a dispersion; (2) Add the dispersion to the catechol-modified epoxy resin, heat to 40-60℃, stir and react to obtain the A material.

5. The epoxy grouting material with high moisture adhesion according to claim 1, characterized in that, The preparation method of the hydrophobic modified filler includes the following steps: B1.1 By mass, take 10 parts of nano-calcium carbonate, 0.5-0.8 parts of stearic acid, 5-8 parts of anhydrous ethanol, and 2-3 parts of deionized water respectively; B1.2 Stearic acid was placed in anhydrous ethanol and heated to dissolve. Then, nano-calcium carbonate was added, and deionized water was added dropwise until the pH value was 7.0-8.

0. The mixture was heated and stirred to react. After cooling to room temperature, it was washed and dried to obtain the hydrophobic modified filler.

6. The epoxy grouting material with high moisture adhesion according to claim 1, characterized in that, The method for preparing the expanded vermiculite includes the following steps: B2.1 Take vermiculite ore, crush it, sieve out particles with a diameter ≤75μm, and calcine it at 750-850℃ for 1-5min to obtain vermiculite; B2.2 Take 80-120 parts by weight of vermiculite, 3-5 parts by weight of silane coupling agent and ethanol-water solution, and set aside for later use; B2.3 Add the silane coupling agent to an ethanol-water solution, adjust the pH to 4.0-5.0, and carry out a hydrolysis reaction; then add vermiculite, heat and stir, and carry out the reaction; after the reaction is completed, filter, wash and dry to obtain the expanded vermiculite.

7. The epoxy grouting material with high moisture adhesion according to claim 5 or 6, characterized in that, The preparation method of material B includes the following steps: (1) Take an amine curing agent, add a hydrophobic modified filler under stirring, then add a dispersant, heat and stir to react and obtain a preliminary mixture; (2) The initial mixture was stirred at 7000-9000 rpm and expanded vermiculite was added. After being dispersed evenly, it was ground until the particle size was ≤1μm and then degassed under vacuum to obtain material B.

8. The epoxy grouting material with high moisture adhesion according to claim 2, characterized in that: In steps A1.1-A1.3, the first step product, the second step product, and the catechol-modified epoxy resin need to be purified after preparation. The purification method of the first step product is as follows: acidify the first step product, add an organic solvent for extraction, combine the organic phases, wash and dry, and then remove the organic solvent by rotary evaporation. The purification method for the second step product is as follows: the second step product is alkalized to transfer the product to the aqueous phase, the aqueous phase is acidified, an organic solvent is added for extraction, the organic phases are combined, washed, dried, and then the organic solvent is removed by rotary evaporation. The purification method of the catechol-modified epoxy resin is as follows: the catechol-modified epoxy resin is cooled to crystallize, washed, and the organic solvent is removed by rotary evaporation.

9. A method for preparing a highly moisture-adhesive epoxy grouting material as described in claim 1, characterized in that, Includes the following steps: S1 Take material A, then add material B to material A at a uniform rate, and add material B over a period of 3-8 minutes to obtain the initial mixture; S2 The initial mixture is first stirred at 40-60 rpm for 3-8 minutes, then stirred at 135-165 rpm for 8-12 minutes, and finally stirred at 280-320 rpm for 1-5 minutes. After standing and maturing, the epoxy grouting material is obtained.

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