Hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material and preparation method thereof

Abstract

The invention discloses a hyperbranched epoxy resin microcapsule slow-release secondary permeation grouting material and a preparation method thereof, and belongs to the technical field of underground engineering anti-seepage reinforcement grouting materials. The hyperbranched epoxy resin microcapsule slow-release type secondary permeation grouting material comprises the following components in parts by volume: 1 part of inorganic skeleton liquid and 1.5-2 parts of mixed liquid of a hyperbranched epoxy resin cross-linking liquid component A and a microcapsule curing liquid component B, wherein the volume ratio of the hyperbranched epoxy resin crosslinking liquid component A (a premixed system of low-viscosity hyperbranched epoxy resin and an anhydride curing agent) to the microcapsule curing liquid component B (polyurea microcapsules wrapped by an amine curing agent) is 1: (0.8-1.2). The grouting material disclosed by the invention has a hyperbranched molecular diffusion enhancement characteristic, a dual-curing strength superimposed effect and long-acting storage stability, can realize accurate regulation and control of grouting construction through a microcapsule slow release technology, and is suitable for concrete structure reinforcement, precise equipment foundation reinforcement and seepage prevention and leakage stoppage in a high-stress environment.

Description

Technical Field

[0001] This invention belongs to the technical field of underground engineering seepage prevention and reinforcement grouting materials, specifically relating to a hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material and its preparation method. Background Technology

[0002] In underground engineering construction, the presence of poorly permeable strata (such as silty fine sand layers) presents numerous challenges. Poorly permeable sand layers are characterized by low compressibility, easy liquefaction, lack of cohesion, and poor stability. Under the influence of groundwater activity, changes in in-situ stress, and disturbances caused by construction work, they are prone to safety accidents such as collapses and water inrushes, and may also lead to groundwater environment damage and structural damage. Therefore, effective reinforcement and seepage prevention treatment of poorly permeable strata are crucial.

[0003] Currently, grouting is one of the commonly used methods for treating difficult-to-permeable strata. Common grouting materials mainly include inorganic grouting materials and organic chemical grouting materials. Inorganic grouting materials are represented by cement-based materials, which have the advantages of low cost and wide availability. However, in difficult-to-permeable strata, cement particles have difficulty penetrating into the tiny pores, resulting in a limited reinforcement range and the inability to form a continuous and effective consolidated body, thus failing to meet the engineering requirements for strata reinforcement and seepage prevention.

[0004] Organic chemical grouting materials, such as traditional epoxy resins and polyurethanes, possess good permeability and bonding properties, and can, to some extent, address the shortcomings of inorganic grouting materials. However, these materials also have some drawbacks. Traditional epoxy resins have high viscosity, limited penetration into microcracks and pores, and their curing time and performance are greatly affected by environmental factors, making precise control difficult. Furthermore, two-component epoxy resins have a short shelf life during storage and transportation due to the tendency for the two components to react, causing inconvenience in engineering applications. While polyurethane materials offer good elasticity and sealing properties, they are more expensive, and the chemical corrosion resistance and durability of some products need improvement.

[0005] In recent years, hyperbranched polymers have attracted widespread attention in the field of materials science due to their unique molecular structure and properties. Hyperbranched epoxy resins possess advantages such as low viscosity, high functionality, and good flowability, theoretically capable of improving the permeability of materials in difficult-to-permeable formations. However, research on the application of hyperbranched epoxy resins in grouting materials is still relatively limited, and their advantages have not yet been fully realized. Meanwhile, microencapsulation sustained-release technology has significant effects on controlling material reaction rates and extending shelf life, but its application in grouting materials is still in its early stages. Therefore, developing a novel grouting material combining hyperbranched epoxy resins and microencapsulation sustained-release technology to improve the material's permeability, controllability, and storage stability is of significant practical importance. Summary of the Invention

[0006] In view of the problems existing in the treatment of difficult-to-permeable strata by existing grouting materials, such as poor permeability of inorganic materials and high viscosity and insufficient storage stability of organic materials, the purpose of this invention is to provide a hyperbranched epoxy resin microcapsule sustained-release secondary permeable grouting material and its preparation method. By employing hyperbranched epoxy resin and microcapsule sustained-release technology, combined with the synergistic effect of organic and inorganic materials, the technical bottlenecks of existing grouting materials are solved, achieving efficient reinforcement and seepage prevention of difficult-to-permeable strata.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] One of the technical solutions of this invention is to provide a hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material, which, by volume, comprises: 1 part of an inorganic framework liquid, and 1.5 to 2 parts of a mixture of hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B; wherein the volume ratio of the hyperbranched epoxy resin crosslinking liquid component A to the microcapsule curing liquid component B is 1:(0.8 to 1.2).

[0009] The inorganic skeleton liquid comprises cement, water, and water-reducing agent in a mass ratio of (55-65):(35-40):(1-3);

[0010] The hyperbranched epoxy resin crosslinking liquid component A comprises a low-viscosity hyperbranched epoxy resin and an acid anhydride curing agent in a mass ratio of (7-8):(2-3).

[0011] The microcapsule curing liquid component B includes an amine curing agent and a polyurea microcapsule wall material in a mass ratio of (3-4):(6-7);

[0012] The viscosity of the low-viscosity hyperbranched epoxy resin is 50–200 mPa·s.

[0013] This invention relates to a hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material. Based on an organic-inorganic composite system, it integrates hyperbranched molecular diffusion enhancement and microcapsule sustained-release technology to achieve efficient reinforcement and seepage prevention of difficult-to-permeable strata through the synergistic effect of multiple components. The invention uses cement grout as the inorganic framework fluid, providing initial strength and rigid support. Hyperbranched epoxy resin crosslinking liquid and microcapsule curing liquid form a permeation crosslinking system. Utilizing the low viscosity and high diffusivity of hyperbranched molecules, as well as the sustained-release effect of microcapsules, secondary permeation and controlled curing are achieved. During grouting, the inorganic framework fluid forms a preliminary consolidation structure in the difficult-to-permeable strata, while the hyperbranched epoxy resin crosslinking liquid permeates and diffuses in the tiny pores around the grout veins. Through a dual curing reaction (anhydride-epoxy + amine-epoxy), a high-strength organic-inorganic composite structure is formed, improving the reinforcement effect and seepage resistance of the strata.

[0014] Preferably, the cement has a fineness of not less than 1000 mesh.

[0015] Optionally, the water-reducing agent is calcium lignosulfonate water-reducing agent.

[0016] Optionally, the anhydride curing agent is one or more combinations of phthalic anhydride, maleic anhydride, and hexahydrophthalic anhydride.

[0017] Optionally, the amine curing agent is one or more combinations of ethylenediamine, diethylenetriamine, triethylenetetramine, and isophoronediamine.

[0018] Optionally, the polyurea microcapsule wall material is a polyurea polymer prepared by interfacial polymerization of hexamethylene diisocyanate and ethylenediamine.

[0019] The second technical solution of the present invention provides a method for preparing the above-mentioned hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material, comprising the following steps:

[0020] First, the inorganic framework liquid, the hyperbranched epoxy resin crosslinking liquid component A, and the microcapsule curing liquid component B are prepared according to the mass ratio of the raw materials; then, the three are mixed according to the volume usage to obtain the hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material.

[0021] Preferably, the mixing order is as follows: first, the hyperbranched epoxy resin crosslinking liquid component A is mixed with the microcapsule curing liquid component B, and then the inorganic framework liquid is added.

[0022] The third technical solution of the present invention provides an application of the above-mentioned hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material in the reinforcement and seepage prevention of difficult-to-permeable sand layers.

[0023] The beneficial technical effects of the present invention are as follows:

[0024] (1) Hyperbranched molecular diffusion enhancement: Hyperbranched epoxy resin has a unique molecular structure, low viscosity and high functionality, which enables it to quickly penetrate into the tiny pores of difficult-to-penetrate strata, and can penetrate 0.03mm microcracks, significantly expanding the grouting reinforcement range.

[0025] (2) Dual curing strength superposition: A dual curing system using anhydride-based curing agents and amine-based curing agents is adopted. The anhydride-epoxy curing reaction provides early strength, while the amine-epoxy curing reaction further enhances later strength. This effectively improves the bearing capacity and stability of the formation.

[0026] (3) The design of component B of the microcapsule curing liquid enables the slow-release function of the curing agent. In the unbroken state, the shelf life of the material is >6 months, solving the problem of short storage period of traditional two-component epoxy resin materials. At the same time, by controlling the timing of microcapsule rupture through shearing, the curing time can be precisely controlled to meet the requirements of different construction processes.

[0027] (4) Environmental protection and corrosion resistance: The material of this invention contains no volatile harmful substances and meets environmental protection requirements. The hyperbranched epoxy resin and the cured composite structure have good chemical corrosion resistance and can maintain stable performance for a long time in harsh underground environments.

[0028] (5) Secondary infiltration and precise construction: The secondary infiltration of the hyperbranched epoxy resin crosslinking liquid can fill the pores and fissures not covered by the inorganic skeleton liquid, improving the overall compactness of the formation. Microencapsulation sustained-release technology makes the grouting process more controllable, achieving precise construction and improving project quality and efficiency. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0030] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0031] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] Example 1

[0035] Preparation of hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material:

[0036] (1) Preparation of inorganic skeleton liquid: Take 60 parts by weight of PI 52.5 ultrafine cement with a fineness of more than 1000 mesh, 38 parts by weight of water, and 2 parts by weight of calcium lignosulfonate water-reducing agent, and mix them evenly with a mortar mixer to obtain inorganic skeleton liquid for later use.

[0037] (2) Preparation of component A of hyperbranched epoxy resin crosslinking liquid: Take 70 parts by weight of 60 mPa·s branched epoxy resin and 30 parts by weight of acid anhydride curing agent, stir evenly to obtain component A of hyperbranched epoxy resin crosslinking liquid, and set aside. Component A of hyperbranched epoxy resin crosslinking liquid is a premixed system, in which the acid anhydride curing agent reacts very slowly with epoxy resin at room temperature without catalysis, and can be stably stored for >6 months. Only after mixing with component B does the amine curing agent release and catalyze the acid anhydride-epoxy reaction, achieving dual curing.

[0038] (3) Preparation of component B of microcapsule curing liquid: Polyurea microcapsules encapsulated with amine curing agent were prepared by interfacial polymerization. 30 parts by weight of amine curing agent and 70 parts by weight of polyurea microcapsule wall material were taken to prepare microcapsules with a particle size of 5 μm, and component B of microcapsule curing liquid was obtained for later use.

[0039] (4) Mix the hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B at a volume ratio of 1:0.8 to obtain a mixture. Then mix the inorganic skeleton liquid with the mixture at a volume ratio of 1:1.5. Stir at a low speed of 300r / min for 3 minutes, and then stir at a high speed of 800r / min for 2 minutes to obtain the hyperbranched epoxy resin microcapsule sustained-release secondary penetration grouting material.

[0040] Example 2

[0041] Preparation of hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material:

[0042] (1) Preparation of inorganic skeleton liquid: Take 60 parts by weight of PI 52.5 ultrafine cement with a fineness of more than 1000 mesh, 38 parts by weight of water, and 2 parts by weight of calcium lignosulfonate water-reducing agent, and mix them evenly with a mortar mixer to obtain inorganic skeleton liquid for later use.

[0043] (2) Preparation of component A of hyperbranched epoxy resin crosslinking liquid: Take 75 parts by weight of low viscosity hyperbranched epoxy resin and 25 parts by weight of acid anhydride curing agent, stir evenly to obtain component A of hyperbranched epoxy resin crosslinking liquid, and set aside.

[0044] (3) Preparation of component B of microcapsule curing liquid: Polyurea microcapsules encapsulated with amine curing agent were prepared by interfacial polymerization. 35 parts by weight of amine curing agent and 65 parts by weight of polyurea microcapsule wall material were taken to prepare microcapsules with a particle size of 7 μm, and component B of microcapsule curing liquid was obtained for later use.

[0045] (4) Mix the hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B at a volume ratio of 1:1 to obtain a mixture. Then mix the inorganic skeleton liquid with the mixture at a volume ratio of 1:1.8. Stir at a low speed of 300r / min for 3 minutes, and then stir at a high speed of 800r / min for 2 minutes to obtain the hyperbranched epoxy resin microcapsule sustained-release secondary penetration grouting material.

[0046] Example 3

[0047] Preparation of hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material:

[0048] (1) Preparation of inorganic skeleton liquid: Take 60 parts by weight of PI 52.5 ultrafine cement with a fineness of more than 1000 mesh, 38 parts by weight of water, and 2 parts by weight of calcium lignosulfonate water-reducing agent, and mix them evenly with a mortar mixer to obtain inorganic skeleton liquid for later use.

[0049] (2) Preparation of component A of hyperbranched epoxy resin crosslinking liquid: Take 80 parts by weight of low viscosity hyperbranched epoxy resin and 20 parts by weight of acid anhydride curing agent, stir evenly to obtain component A of hyperbranched epoxy resin crosslinking liquid, and set aside.

[0050] (3) Preparation of component B of microcapsule curing liquid: Polyurea microcapsules encapsulated with amine curing agent were prepared by interfacial polymerization. 40 parts by weight of amine curing agent and 60 parts by weight of polyurea microcapsule wall material were taken to prepare microcapsules with a particle size of 10 μm, and component B of microcapsule curing liquid was obtained for later use.

[0051] (4) Mix the hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B at a volume ratio of 1:1.2 to obtain a mixture. Then mix the inorganic skeleton liquid with the mixture at a volume ratio of 1:2, stir at a low speed of 300r / min for 3 minutes, and then stir at a high speed of 800r / min for 2 minutes to obtain the hyperbranched epoxy resin microcapsule sustained-release secondary penetration grouting material.

[0052] Comparative Example 1

[0053] Compared with Example 1, the difference is that only inorganic framework liquid is used, and hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B are not added. Everything else is the same as Example 1.

[0054] Comparative Example 2

[0055] Compared with Example 1, the difference is that the inorganic framework liquid is not added, and only the hyperbranched epoxy resin crosslinking liquid component A and the microcapsule curing liquid component B are used. Everything else is the same as in Example 1.

[0056] Comparative Example 3

[0057] Common epoxy resin grouting materials available on the market are used, and the materials are prepared and used in accordance with their instructions.

[0058] The grouting materials prepared in Examples 1-3 and Comparative Examples 1-3 are mixed before use and injected into the impermeable sand layer through a two-liquid grouting device during field application.

[0059] Under the conditions of grouting pressure of 0.1 MPa and dynamic water flow velocity of 0.5 m / s, the performance of the grouting materials prepared in Examples 1-3 and Comparative Examples 1-3 was measured and compared.

[0060] Viscosity was tested using a rotational viscometer (e.g., NDJ-8S type, rotor No. 3). During testing, the sample was placed in a constant temperature water bath at 25±0.5℃ for 30 minutes, stirred at 60 r / min, and the viscosity value was recorded after the reading stabilized for 2 minutes. The measurement was repeated three times, and the average value was taken to ensure that the data error did not exceed 5%.

[0061] Gelation time: The viscosity change of the material was monitored using a rotational viscometer. The grouting material was mixed according to the formula and immediately poured into the sample cup. It was stirred at 100 r / min, and the viscosity change over time was recorded in real time. The gelation time was defined as the time interval when the viscosity suddenly increased to 10 times the initial value. The test temperature was controlled at 25±1℃.

[0062] Compressive strength: Prepare cylindrical specimens with a diameter of 50 mm and a height of 100 mm. Use an electro-hydraulic servo pressure testing machine to apply load at a rate of 0.5–0.8 MPa / s until the specimen fails. Record the failure load and calculate the compressive strength of the specimen, in MPa. The compressive strength value is taken as the arithmetic mean of the test results of three specimens, accurate to 0.1 MPa.

[0063] When testing the adhesive strength of the test materials, a sand-based substrate is first prepared with a dry density of 1.65 g / cm³. 3 The sand column is made by filling a Φ50mm×100mm mold and compacting it in layers. After curing for 24 hours, the surface of the sand substrate is wiped clean. During the gelation time, the grouting material is injected into the surface of the sand substrate to form a 5-8mm bonding layer. The same substrate is then bonded together and a pre-pressure of 0.1MPa is applied. Standard curing is carried out for 7 days and 28 days. The load is applied at a rate of 0.5mm / min using an electronic universal testing machine.

[0064] The material retention rate was calculated by using the circular tube flushing method. The cured grouting material specimen was placed in a transparent circular tube to simulate a dynamic water environment. The water flow rate was controlled by a water pump, and the erosion was continuously flushed for a certain period of time. The lost material was collected, dried, weighed, and the retention rate was calculated to evaluate the erosion resistance of the material in flowing water.

[0065] The permeability of the material was tested using a constant head permeability test apparatus. The prepared grouting material was cured and formed into a cylindrical standard specimen, which was then installed in the permeameter. A stable head difference was applied across the specimen to maintain a stable water flow through it. The amount of water passing through the specimen within a certain time was measured, and Darcy's law was used to calculate the material's permeability coefficient.

[0066] The test results are shown in Table 1 below.

[0067] Table 1. Performance test results of the grouting materials prepared in Examples 1-3 and Comparative Examples 1-3

[0068]

[0069] Table 1 shows that the synergistic effect of hyperbranched epoxy resin crosslinking liquid, microcapsule curing liquid, and inorganic framework liquid significantly improves material performance. Materials without hyperbranched epoxy resin crosslinking liquid and microcapsule curing liquid exhibit lower compressive and bond strengths; materials without inorganic framework liquid have better permeability, but insufficient solidified strength and bonding performance, failing to meet the strength requirements of practical engineering. Compared with commonly available ordinary epoxy resin grouting materials, the hyperbranched epoxy resin microcapsule slow-release secondary permeation grouting material of this invention has significant advantages in compressive strength, bond strength, and permeability. Furthermore, the microcapsule slow-release technology effectively extends the material's shelf life, and the curing time can be precisely controlled by adjusting the stirring conditions to meet different construction needs.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material, characterized in that, The components, by volume, include: 1 part of inorganic framework liquid, and 1.5 to 2 parts of a mixture of hyperbranched epoxy resin crosslinking liquid component A and microcapsule curing liquid component B; wherein the volume ratio of the hyperbranched epoxy resin crosslinking liquid component A to the microcapsule curing liquid component B is 1:(0.8 to 1.2). The inorganic skeleton liquid comprises cement, water, and water-reducing agent in a mass ratio of (55-65):(35-40):(1-3); The hyperbranched epoxy resin crosslinking liquid component A comprises a low-viscosity hyperbranched epoxy resin and an acid anhydride curing agent in a mass ratio of (7-8):(2-3). The microcapsule curing liquid component B includes an amine curing agent and a polyurea microcapsule wall material in a mass ratio of (3-4):(6-7); The viscosity of the low-viscosity hyperbranched epoxy resin is 50–200 mPa·s.

2. The hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to claim 1, characterized in that, The fineness of the cement is not less than 1000 mesh.

3. The hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to claim 1, characterized in that, The water-reducing agent is calcium lignosulfonate water-reducing agent.

4. The hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to claim 1, characterized in that, The anhydride curing agent is one or more of phthalic anhydride, maleic anhydride, and hexahydrophthalic anhydride.

5. The hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to claim 1, characterized in that, The amine curing agent is one or more combinations of ethylenediamine, diethylenetriamine, triethylenetetramine, and isophoronediamine.

6. The hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to claim 1, characterized in that, The polyurea microcapsule wall material is a polyurea polymer prepared by interfacial polymerization of hexamethylene diisocyanate and ethylenediamine.

7. A method for preparing a hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to any one of claims 1 to 6, characterized in that, Includes the following steps: First, the inorganic framework liquid, the hyperbranched epoxy resin crosslinking liquid component A, and the microcapsule curing liquid component B are prepared according to the mass ratio of the raw materials; then, the three are mixed according to the volume usage to obtain the hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material.

8. The preparation method according to claim 7, characterized in that, The mixing sequence is as follows: first, the hyperbranched epoxy resin crosslinking liquid component A is mixed with the microcapsule curing liquid component B, and then the inorganic framework liquid is added.

9. The application of the hyperbranched epoxy resin microcapsule sustained-release secondary permeation grouting material according to any one of claims 1 to 6 in the reinforcement and seepage prevention of difficult-to-permeable sand layers.

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