Epoxy resin composition and grouting material

Abstract

The application discloses an epoxy resin composition and a grouting material, by introducing a specially designed bio-based branched epoxy resin, utilizing the synergistic effect of the bio-based branched epoxy resin flexible chain segment + multi-epoxy functional group + molecular cavity free volume, based on the in-situ toughening mechanism, the structure which can effectively dissipate energy is constructed in the epoxy resin curing network; combined with the matched composite amine curing system, the synergistic improvement of high strength and high toughness of the grouting material is successfully realized, so as to ensure the excellent durability and performance stability of the grouting material in the harsh environment such as long-term vibration and dynamic load, and meet the urgent needs of long-term maintenance of modern rail transit infrastructure.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a high-strength, high-toughness epoxy resin composition and a grouting material containing the same, as well as its preparation method and application, particularly suitable for grouting and reinforcing concrete cracks in subway tunnels under subway train vibration conditions. Background Technology

[0002] Subway structures may develop defects in the early stages of construction, and since most are located below the groundwater level, water leakage is the most frequent problem in operating tunnels. Water leakage can exacerbate structural cracking, corrode interior finishes and equipment, reduce train operating efficiency and safety, and in severe cases, even lead to transportation disruptions, causing significant casualties and economic losses.

[0003] For leaks caused by cracks in concrete structures, the industry typically uses epoxy-based chemical grouting materials for sealing. The industry standard JC / T 1041—2007, "Epoxy Resin Grouting Materials for Concrete Cracks," sets strict requirements for Type II N grouting materials: grout viscosity < 200 mPa·s, workable time > 30 min, compressive strength ≥ 70 MPa, tensile shear strength ≥ 8 MPa, tensile strength ≥ 15 MPa, dry bonding ≥ 4.0 MPa, wet bonding ≥ 2.5 MPa, seepage pressure ≥ 1.2 MPa, and seepage pressure ratio ≥ 400%. While epoxy grouting materials meeting this standard possess excellent mechanical properties and bonding strength, combining reinforcement and leak-sealing functions, their high cross-linking density in cured products generally results in brittleness, low impact strength, and easy peeling under vibration conditions, severely hindering their application in vibrating environments (such as subway tunnels).

[0004] Currently, the epoxy resin grouting materials used in subway tunnel leakage plugging projects generally do not consider the long-term weakening effect of train vibration on material properties, leading to widespread re-leakage and wasted resources. Specifically, common methods for toughening epoxy resin grouting materials include:

[0005] (1) Introduction of flexible polyurethane segment modified bisphenol A type epoxy resin: Invention patent CN 115404034 A discloses an epoxy resin grouting material and its preparation method. A polyurethane prepolymer is prepared by reacting hydroxyl-terminated liquid rubber, polyether triol and 2,4-toluene diisocyanate, and then reacting it with the hydroxyl groups in bisphenol A type epoxy resin to obtain a flexible polyurethane segment modified liquid epoxy resin. The cured epoxy resin grouting material has greater flexibility and elongation at break. However, the flexible polyurethane segment modified liquid epoxy resin prepared by this method generally has high viscosity, requiring a large amount of reactive diluent to reduce the viscosity. Therefore, the cured epoxy resin grouting material has low strength and cannot meet the requirements of the N-type II index specified in JC / T 1041—2007.

[0006] (2) Introduction of liquid rubber: Invention patent CN 108084663 A discloses a highly elastic modified epoxy resin grouting material for sealing leaks and its preparation method. By introducing multifunctional epoxy resin, nylon-modified bisphenol A type epoxy resin, and core-shell liquid rubber into component A of a two-component bisphenol A epoxy resin sealing material, it achieves synergistic effects with the bisphenol A type epoxy resin, resulting in a specific formulation of component A. This component A can be mixed with component B containing a phenolic amine curing agent to form a highly elastic solid, achieving a waterproof and leak-sealing effect. However, the initial viscosity of the epoxy resin grouting material prepared by this method is much greater than 200 mPa·s, and its cured product properties cannot meet the N-type II index requirements specified in JC / T 1041—2007 in terms of strength.

[0007] (3) Introduction of Flexible Epoxy Resin: Invention Patent CN 104673161 A discloses a flexible epoxy grease sealing material and its preparation method and application. This flexible epoxy grease sealing material is composed of component A and component B in a weight ratio of 100:(30-50). Component A contains, by mass percentage: 70-80% polyether diol modified bisphenol F type epoxy resin, 5-20% flexible epoxy resin, and 10-20% reactive diluent. Component B contains, by mass percentage: 51% cashew nut shell powder, 5% paraformaldehyde powder, 24-30% triethylenetetramine, 9-15% polyetheramine D230, and 5-8% diethanolamine. This flexible epoxy grease sealing material can cure quickly and can be applied to rapid sealing projects in subway, high-speed rail, and highway tunnels, as well as concrete cracks affected by vibration. However, the initial viscosity of the epoxy resin grouting material prepared by this method is greater than 200 mPa·s, and the strength of its cured product cannot meet the requirements of the N-type II index specified in JC / T 1041—2007.

[0008] (4) Introduction of flexible epoxy resin curing agent: The literature "Development of Curing Agent for Flexible Epoxy Resin Sealing Material" (10.15901 / j.cnki.1007-497x.2017.20.001) discloses the development of a curing agent for flexible epoxy resin sealing material. A phenolic amine curing agent was synthesized via the Mannes reaction using long-chain phenols, aldehydes, and low-molecular-weight polyamines as raw materials. This curing agent was then compounded with polyether amines and a curing accelerator to prepare a flexible epoxy resin sealing material with low viscosity that can cure rapidly underwater. However, the epoxy resin grouting material prepared in this literature also fails to meet the requirements of the N-type II index specified in JC / T 1041—2007 in terms of initial viscosity and cured product properties. Summary of the Invention

[0009] To address the frequent recurrence of leaks after sealing in subway vibration environments, this invention provides an epoxy resin composition and grouting material. By introducing a uniquely designed bio-based branched epoxy resin, and utilizing the synergistic effect of flexible segments, multiple epoxy functional groups, and free volume of molecular cavities in the bio-based branched epoxy resin, an energy-dissipating structure is constructed within the epoxy resin curing network based on an in-situ toughening mechanism. Combined with a compatible composite amine curing system, a synergistic improvement in the grouting material's high strength and high toughness is successfully achieved. This ensures excellent durability and performance stability under harsh environments such as long-term vibration and dynamic loads, meeting the urgent need for long-term maintenance in modern rail transit infrastructure.

[0010] The technical solution of this invention is as follows:

[0011] The epoxy resin composition comprises 70-75 parts of bisphenol A type epoxy resin, 3-12 parts of bio-based branched epoxy resin, and 18-22 parts of reactive diluent.

[0012] Among them, bio-based branched polyols are synthesized under solvent-free conditions, and bio-based branched epoxy resins are synthesized after introducing IG, a semi-addition product of polyurethane-epoxy containing epoxy groups, into the bio-based branched polyols for modification.

[0013] The epoxy resin composition described above uses one or more of the following reactive diluents: phenyl glycidyl ether (reactive diluent 690), o-tolyl glycidyl ether (reactive diluent 691), benzyl glycidyl ether (reactive diluent 692), and 1,4-butanediol diglycidyl ether (reactive diluent 622).

[0014] The bisphenol A type epoxy resin in the above-mentioned epoxy resin composition is bisphenol A type epoxy resin E51.

[0015] The above-mentioned epoxy resin composition, the synthesis process of the bio-based branched epoxy resin includes:

[0016] Step P1. Synthesize bio-based branched polyol ED solution:

[0017] Epoxidized soybean oil, a polyfunctional alkyd compound, and an appropriate amount of catalyst are placed in a reaction apparatus. Under stirring and heating conditions, the epoxy groups of the epoxidized soybean oil and the active groups of the alkyd compound undergo a ring-opening addition reaction until the epoxy groups in the system are completely consumed. The resulting bio-based branched polyol is cooled to a suitable temperature and an appropriate amount of organic solvent is added for dispersion to form a homogeneous solution for later use.

[0018] Step P2. Synthesis of intermediate IG solution:

[0019] Aliphatic diisocyanate, catalyst and solvent are added to the reaction apparatus and heated to the set temperature. When the epoxy value is lower than 0.1%, an alcohol compound containing epoxy groups is slowly and evenly added dropwise to the reaction apparatus. Under the protection of an inert atmosphere, the alcohol compound containing epoxy groups undergoes a selective addition reaction with specific functional groups of diisocyanate to obtain epoxy functionalized intermediate IG solution.

[0020] Step P3. Mix the bio-based branched polyol solution with the intermediate IG solution to synthesize the bio-based branched epoxy resin:

[0021] The IG solution prepared in step P2 is slowly added to the ED solution in step P1 under controlled conditions. The reaction temperature is increased and the reaction is carried out under an inert atmosphere. After the reaction is completed, a small amount of end-capping agent is added to ensure that the residual isocyanate groups react completely. The solvent is removed by rotary evaporation to obtain the final product, namely the bio-based branched epoxy resin.

[0022] The specific synthesis process of bio-based branched epoxy resin includes

[0023] Step S1. Synthesize a bio-based branched polyol solution:

[0024] Take 19.51 parts of epoxidized soybean oil, 10.73 parts of 2,2-bis(hydroxymethyl)propionic acid and 0.09 parts of amine catalyst and put them into a three-necked flask equipped with a mechanical stirrer and a condenser. After mechanical stirring, heat to 120°C until the epoxy value is lower than 0.1% and stop the reaction to obtain a bio-based branched polyol. Cool the bio-based branched polyol to 60°C, add 30 parts of 1,4-dioxane solvent, stir and mix to obtain a bio-based branched polyol solution for later use.

[0025] Step S2. Synthesis of intermediate IG solution: 53.35 parts of isophorone diisocyanate, 0.04 parts of dibutyltin dilaurate catalyst and 70 parts of 1,4-dioxane solvent were put into a three-necked flask and heated to 40°C. 17.78 parts of glycidol were added dropwise to the above reaction flask through a constant pressure dropping funnel over 30 minutes. After mechanical stirring, nitrogen gas was purged and the reaction was carried out in a constant temperature oil bath at 40°C for 5 hours to obtain intermediate IG solution.

[0026] Step S3. Mix the bio-based branched polyol solution and the intermediate IG solution to synthesize the bio-based branched epoxy resin: Add the IG solution obtained in step S2 dropwise to the reaction flask of step S1 through a constant pressure dropping funnel over 45 minutes, heat to 60°C, and react for 5 hours under nitrogen protection. Then add 2 parts of anhydrous ethanol and continue the reaction for 30 minutes to ensure that all isocyanate groups react completely. Remove the solvent by rotary evaporation to obtain a brownish-yellow transparent viscous liquid product, which is the bio-based branched epoxy resin.

[0027] In the above-mentioned epoxy resin composition, after synthesizing the bio-based branched polyol, the number of terminal epoxy groups carried on each molecule of the synthesized bio-based branched epoxy resin is controlled by adjusting the molar ratio of intermediate IG to the core of the synthesized bio-based branched polyol.

[0028] A grouting material includes component A and component B. Component A is the above-mentioned epoxy resin composition, and component B includes 18-25 parts of modified cycloaliphatic amine, 43-50 parts of polyether amine, 10-15 parts of isophorone diamine, 8-13 parts of m-phenylenediamine, 3-6 parts of accelerator, and 3-5 parts of aminosilane coupling agent.

[0029] In this invention, the modified alicyclic amine is one or both of R-3618 (active hydrogen equivalent 165) and R-3623 (active hydrogen equivalent 160) from Ruichi Chemical (Guangdong) Co., Ltd. Such modified alicyclic amines have low odor, fast curing, good toughness, and excellent water resistance and adhesion for underwater construction.

[0030] The aforementioned grouting material, polyetheramine, is a polyoxypropylene compound mainly end-capped by primary amino groups, with a molecular weight of approximately 230.

[0031] The above-mentioned grouting material uses an aminosilane coupling agent that is one or any two of γ-aminopropyltriethoxysilane (KH-550), N-β-(aminoethyl)γ-aminopropyltriethoxysilane coupling agent (KH-791), and N-β-(aminoethyl)γ-aminopropyltrimethoxysilane coupling agent (KH-792).

[0032] The accelerator in the above-mentioned grouting material is one or both of 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) and triethylamine.

[0033] The above-mentioned grouting material is prepared by mixing component A and component B at a mass ratio of 3:1 at room temperature to complete the preparation of the grouting material slurry.

[0034] The grouting material is injected into the concrete cracks using a single-liquid grouting machine. The grouting material is left to cure at room temperature for several days to obtain a resin casting, which enables the application of grouting and sealing reinforcement of concrete cracks in subway tunnels under the vibration conditions of subway trains.

[0035] Soybeans, as one of the most widely planted and highest-yielding oilseed crops, produce epoxides, namely epoxidized soybean oil (ESO), whose molecular structure is rich in epoxy groups and flexible long-chain fatty acids. Through the ring-opening reaction of ESO epoxy groups, ideal bio-based branched epoxy resin precursors can be prepared. Bio-based branched epoxy resins, possessing both the flexible core chain of soybean oil and multiple active epoxy groups at the ends, are ideal toughening modifiers for traditional bisphenol A type epoxy resin grouting materials. They overcome the inherent brittleness of epoxy resins and align with the development direction of green chemistry.

[0036] Bio-based branched epoxy resins possess a highly branched structure with minimal intermolecular chain entanglement, exhibiting lower bulk melt viscosity and solution viscosity compared to linear bisphenol A type epoxy resins of similar molecular weight. The numerous epoxy groups on the periphery of bio-based branched epoxy resins ensure excellent compatibility with conventional epoxy resins; during curing, they do not precipitate but instead form a homogeneous system. The loose branched structure of bio-based branched epoxy resins contains a large number of vacancies and defects (free volumes). Introducing them into the epoxy system increases intramolecular and intermolecular free volumes. When the cured material is subjected to external forces (such as impact), these free volumes can deform, inducing extensive internal shear deformation to dissipate energy, thereby significantly improving the material's impact toughness and meeting the service requirements of subway vibration environments.

[0037] According to the above-described solution, the beneficial effects of this invention are as follows:

[0038] 1. Molecular design achieves high toughness and high strength: Through the unique design of bio-based branched epoxy resin (flexible soybean oil segments + 8-12 epoxy functional groups + free volume of molecular cavity), in-situ toughening is achieved. At a 9% addition (ED-IG10), the tensile strength of the cured material reaches 47MPa (93% higher than the traditional method), and the elongation at break reaches 11.2% (128.6% higher), successfully solving the contradiction of "high strength is brittle, and high toughness is weak" in epoxy grouting materials.

[0039] 2. The synthesis process is efficient, stable, green and environmentally friendly: It adopts a process of low-temperature selective addition (40℃ to synthesize IG) + controlled grafting (60℃ to connect ED), which avoids high-temperature side reactions, eliminates the risk of gelation, and provides mild reaction conditions. The ED synthesis stage is solvent-free, which significantly reduces energy consumption and cost. The product has good stability, is easy to industrialize, and promotes the application of renewable bio-based resources.

[0040] 3. Optimized curing system enhances adhesion and toughness: Component B is compounded with modified alicyclic amines, polyether amines, aromatic diamines, aminosilane coupling agents, etc. Aminosilanes significantly enhance the adhesion between resin and concrete, while modified alicyclic amines and polyether amines synergistically contribute to the tough crosslinking network. Aromatic diamines provide excellent mechanical strength, heat resistance and solvent resistance. The cured product has both high strength and high toughness.

[0041] 4. Excellent construction performance, with overall performance far exceeding standards: This invention uses bio-based branched polyols as raw materials for grouting materials. The grout has a low initial viscosity (<200 mPa·s) and a long working time (>30 min), ensuring excellent permeability to micro-cracks. The properties of the cured product comprehensively exceed the highest industry standards (JC / T1041-2007 Type II), such as compressive strength of 89 MPa, impermeability pressure ratio of 500%, and tensile shear strength of 19.7 MPa, meeting stringent engineering requirements.

[0042] 5. Excellent vibration fatigue resistance, eradicating the problem of re-leakage: The specially formulated material ratio endows the cured material with excellent fatigue resistance. After testing in a simulated vibration environment (5Hz, amplitude 20mm, approximately 6 million cycles over 14 days), the tensile shear strength retention rate is >80% (>15MPa), far superior to traditional materials (<50%), fundamentally solving the industry pain point of frequent re-leakage after sealing in vibration environments such as subway tunnels. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of the bio-based branched epoxy resin (ED-IG12) of the present invention;

[0045] Figure 2 This is a schematic diagram of the synthesis route of the bio-based branched epoxy resin (ED-IG12) of the present invention;

[0046] Figure 3 The infrared spectrum of the bio-based branched epoxy resin (ED-IG12) of this invention is shown below.

[0047] Figure 4 The hydrogen spectrum of the raw materials ESO and bio-based polyol ED used in this invention;

[0048] Figure 5 This is the hydrogen spectrum of the bio-based branched epoxy resin (ED-IG12) of this invention;

[0049] Figure 6 Here is a SEM image of the impact fracture surface of the material in Example 8 of this invention;

[0050] Figure 7 This is a SEM image of the impact fracture surface of the material in Comparative Example 1 of this invention.

[0051] Figure 8 This is a SEM image of the impact fracture surface of the material in Comparative Example 2 of this invention. Detailed Implementation

[0052] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0053] This invention provides a bio-based branched epoxy resin, with the following structural formula: Figure 1 As shown.

[0054] This invention synthesizes a bio-based branched polyol (ED) under solvent-free conditions in a one-step process, and obtains a bio-based branched epoxy resin by modifying the IG semi-addition product of polyurethane-epoxy containing epoxy groups. The synthesis steps are as follows: Figure 2 As shown. In the synthesis of intermediate IG, the catalyst DBTDL makes the secondary-NCO group of IPDI more active than the primary-NCO group. At a relatively low temperature of 40℃, the reaction rates of the two groups are significantly different, with the reaction mainly occurring between the hydroxyl group of glycidol and the secondary-NCO group of IPDI, to obtain intermediate IG with a specific structure.

[0055] By adjusting the molar ratio of introduced IG, the number of terminal epoxy groups in the product (8-12) can be precisely controlled, resulting in a series of products such as bio-based branched epoxy resin ED-IG8, bio-based branched epoxy resin ED-IG10, and bio-based branched epoxy resin ED-IG12. Using the molar amount of the bio-based branched polyol ED core as a baseline (usually set to 1.0 equivalent, i.e., 1.0 eq), the molar amount of IG can be varied to be several times that of ED. For example, in the embodiments:

[0056] 8.0 eq of IG was added to obtain the product ED-IG8 (target: 8 epoxy groups).

[0057] 10.0 eq of IG was added to obtain the product ED-IG10 (target: 10 epoxy groups).

[0058] 12.0 eq of IG was added to obtain the product ED-IG12 (target: 12 epoxy groups).

[0059] Through screening, specific varieties of bisphenol A type epoxy resin grouting materials with the best reinforcing and toughening effects can be obtained.

[0060] Specifically, the bio-based branched epoxy resin synthesis process provided by this invention, taking ED-IG12 as an example, includes the following steps:

[0061] (1) Preparation of prepolymer: Under solvent-free conditions, epoxidized soybean oil (ESO) and 2,2-dimethylolpropionic acid (DMPA) were reacted through a ring-opening reaction to obtain a bio-based branched polyol (ED), which was then dissolved in 1,4-dioxane solvent to form a homogeneous solution;

[0062] (2) Intermediate synthesis: Isophorone diisocyanate (IPDI) and glycidol were reacted in equal amounts under low temperature conditions to prepare a low viscosity, structure-controllable isocyanate-terminated intermediate (IG).

[0063] (3) Grafting reaction: The intermediate IG is added dropwise to the ED solution, and the branched chain is extended through the condensation reaction of the isocyanate group and the hydroxyl group. Anhydrous ethanol is added at the end of the reaction to seal the end and ensure that the isocyanate group is completely converted.

[0064] The final product viscosity is < that of E51 epoxy resin. Storage stability is >12 months, meeting industrial application requirements.

[0065] The following is a brief description of the embodiments and comparative examples.

[0066] Example 1 provides a bio-based branched epoxy resin (ED-IG12) and its synthesis method.

[0067] Example 2 provides a bio-based branched epoxy resin (ED-IG10) and its synthesis method.

[0068] Example 3 provides a bio-based branched epoxy resin (ED-IG8) and its synthesis method.

[0069] Examples 4-9 provide high-strength, high-toughness epoxy resin compositions containing different proportions of bio-based branched epoxy resin and grouting materials made therefrom.

[0070] Comparative Example 1 is a bisphenol A type epoxy resin grouting material that does not contain bio-based branched epoxy resin. Compared with Example 8, this resin composition does not contain bio-based branched epoxy resin toughening agent.

[0071] Comparative Example 2 is a bisphenol A type epoxy resin grouting material that does not contain bio-based branched epoxy resin. Compared with Example 8, this resin composition uses polyether diol modified bisphenol prepared in Example 2 of Chinese Patent CN 104673161 A.

[0072] Example 1

[0073] A bio-based branched epoxy resin (ED-IG12) has the following synthetic route: Figure 2 As shown, the specific synthesis method is as follows.

[0074] Step A1. Synthesize a bio-based branched polyol (ED) solution.

[0075] 19.51 parts of epoxidized soybean oil (ESO, 0.02 mol, 1.0 eq), 10.73 parts of 2,2-bis(hydroxymethyl)propionic acid (DMPA, 0.08 mol, 4.0 eq), and 0.09 parts of amine catalyst were added to a three-necked flask equipped with a mechanical stirrer and a condenser. After mechanical stirring, the mixture was heated to 120°C. The epoxy value was titrated every 2 hours until it fell below 0.1%, at which point the reaction was stopped, yielding a bio-based branched polyol (ED) with a hydroxyl value of (440 ± 5) mg KOH / g.

[0076] The bio-based branched polyol was cooled to 60°C, and 30 parts of 1,4-dioxane solvent were added and stirred to obtain a bio-based branched polyol (ED) solution for later use.

[0077] Step A2. Synthesize intermediate IG (isocyanate-terminated intermediate) solution.

[0078] Take 53.35 parts of isophorone diisocyanate (IPDI, 12.0 eq), 0.04 parts of dibutyltin dilaurate (DBTDL) catalyst and 70 parts of 1,4-dioxane solvent and put them into a three-necked flask, and heat to 40℃.

[0079] 17.78 parts of glycidol (12.0 eq) were added dropwise to the above reaction flask over 30 minutes using a constant pressure dropping funnel. The mixture was mechanically stirred, protected with nitrogen, and reacted in a constant temperature oil bath at 40°C for 5 hours to obtain the intermediate IG solution.

[0080] Step A3. Mix the bio-based branched polyol (ED) solution with the intermediate IG solution to synthesize the bio-based branched epoxy resin ED-IG12.

[0081] The IG solution obtained in step A2 was added dropwise to the reaction flask in step A1 over 45 minutes using a constant pressure dropping funnel. The temperature was raised to 60°C, and the reaction was carried out for 5 hours under nitrogen protection.

[0082] Then add 2 parts of anhydrous ethanol and continue the reaction for 30 minutes to ensure that all isocyanate groups react completely. Remove the solvent by rotary evaporation to obtain a brownish-yellow transparent viscous liquid product, namely bio-based branched epoxy resin ED-IG12.

[0083] The structure of the bio-based branched epoxy resin ED-IG12 synthesized using the above preparation method is as follows: Figure 1 As shown, 8-12 R's are The remaining R values ​​are -OH.

[0084] like Figure 3As shown, in the FTIR spectrum of the bio-based branched polyol ED, after the ring-opening reaction of ESO and DMPA, the peak value at 832 cm⁻¹ is obtained. -1 The absorption peak of the epoxy group represented by the location disappeared, while a broad and strong hydroxyl absorption peak appeared at 3467 cm⁻¹, and at 1696 cm⁻¹... -1 No carbonyl absorption peak was found in the raw material DMPA, indicating that the carboxyl group of DMPA was completely consumed, which shows that the reaction between epoxidized soybean oil and DMPA was complete, and bio-based branched polyol ED was generated.

[0085] In the FTIR spectrum of bio-based branched epoxy resin ED-IG12, 3350 cm⁻¹ -1 and 1536cm -1 The absorption peaks for the stretching and bending vibrations of NH are 1723 cm⁻¹. -1 The peaks at 1240 cm⁻¹ are characteristic absorption peaks of the carbonyl group (C=O), and the presence of these peaks indicates the formation of a urethane group (-NH-COO-). -1 The absorption peak detected at wavenumber corresponds to the CO vibration of the urethane bond in the molecule; at 1042 cm⁻¹... -1 The absorption peak detected at the wavenumber corresponds to the CO vibration of the ether bond in the molecule.

[0086] ED-IG12 at 2270cm -1 No characteristic absorption peak of -NCO was found at 910 cm⁻¹, proving that the NCO group of intermediate IG and the hydroxyl group of ED reacted completely, and the peak was observed at 910 cm⁻¹. -1 An asymmetric stretching vibration peak of the epoxy ring appeared at the location.

[0087] In summary, the target product, bio-based branched epoxy resin ED-IG12, has been successfully prepared.

[0088] like Figure 4 As shown, in ESO's H 1 In the -NMR spectrum, the proton peaks at chemical shifts of 2.6–2.8 represent epoxy groups. (ED H...) 1 In the NMR spectrum, the proton peaks of the epoxide with chemical shifts at 2.6–2.8 have completely disappeared. The proton peaks with chemical shifts at 4.1–4.4 and 3.4–3.5 are attributed to the proton peaks of the methylene group bonded to the ester group (—OCOCH2) and the hydroxyl group (—CH2OH), indicating that the epoxide group has been completely consumed and a large number of hydroxyl groups have been produced.

[0089] like Figure 4 As shown, in ED-IG12 H 1In the -NMR spectrum, the proton peak at chemical shifts of 3.4–3.5 ppm decreases sharply, indicating that the hydroxyl groups in ED are completely consumed by the reaction with IG. The characteristic peaks at 0.8–2.4 ppm are attributed to different proton peaks on the methyl, methylene, and methine groups. Furthermore, in the ED-IG12... 1 In the HNMR spectrum, such as Figure 5 As shown, proton peaks of the epoxy group are displayed at positions of 3.2, 2.8, and 2.6 ppm.

[0090] H above 1 The NMR and FT-IR characterization results corroborate each other, indicating that the structure of the synthesized ED-IG12 is consistent with the expected structure.

[0091] Example 2

[0092] A bio-based branched epoxy resin (ED-IG10) has the following synthetic route: Figure 2 As shown, the specific synthesis method is as follows.

[0093] Step B1. Synthesize a bio-based branched polyol ED solution.

[0094] 19.51 parts of epoxidized soybean oil (ESO, 0.02 mol, 1.0 eq), 10.73 parts of 2,2-bis(hydroxymethyl)propionic acid (DMPA, 0.08 mol, 4.0 eq), and 0.09 parts of amine catalyst were added to a three-necked flask equipped with a mechanical stirrer and a condenser. After mechanical stirring, the mixture was heated to 120°C. The epoxy value was titrated every 2 hours until it fell below 0.1%, at which point the reaction was stopped. This yielded the bio-based branched polyol ED with a hydroxyl value of (440±5) mgKOH / g.

[0095] The bio-based branched polyol was cooled to 60°C, and 30 parts of 1,4-dioxane solvent were added and stirred to obtain a bio-based branched polyol (ED) solution for later use.

[0096] Step B2. Synthesize the intermediate IG solution.

[0097] Take 44.46 parts of isophorone diisocyanate (IPDI, 10.0 eq), 0.04 parts of dibutyltin dilaurate (DBTDL) catalyst and 60 parts of 1,4-dioxane solvent and put them into a three-necked flask, and heat to 40℃.

[0098] 14.81 parts of glycidol (10.0 eq) were added dropwise to the above reaction flask over 30 minutes using a constant pressure dropping funnel. The mixture was mechanically stirred, protected with nitrogen, and reacted in a constant temperature oil bath at 40°C for 5 hours to obtain the intermediate IG solution.

[0099] Step B3. Mix the bio-based branched polyol (ED) solution with the intermediate IG solution to synthesize the bio-based branched epoxy resin ED-IG10.

[0100] The IG solution obtained in step B2 was added dropwise to the reaction flask in step B1 over 45 minutes using a constant pressure dropping funnel. The temperature was raised to 60°C, and the reaction was carried out for 5 hours under nitrogen protection.

[0101] Then add 2 parts of anhydrous ethanol and continue the reaction for 30 minutes to ensure that all isocyanate groups react completely. Remove the solvent by rotary evaporation to obtain a brownish-yellow transparent viscous liquid product, namely bio-based branched epoxy resin ED-IG10.

[0102] The structure of the bio-based branched epoxy resin ED-IG10 synthesized by the above preparation method is similar to that of ED-IG12, so its structural characterization will not be described in detail.

[0103] Example 3

[0104] A bio-based branched epoxy resin (ED-IG8) has the following synthetic route: Figure 2 As shown, the specific synthesis method is as follows.

[0105] Step C1. Synthesize a bio-based branched polyol ED solution.

[0106] 19.51 parts of epoxidized soybean oil (ESO, 0.02 mol, 1.0 eq), 10.73 parts of 2,2-bis(hydroxymethyl)propionic acid (DMPA, 0.08 mol, 4.0 eq), and 0.09 parts of amine catalyst were added to a three-necked flask equipped with a mechanical stirrer and a condenser. After mechanical stirring, the mixture was heated to 120°C. The epoxy value was titrated every 2 hours until it fell below 0.1%, at which point the reaction was stopped. This yielded the bio-based branched polyol ED with a hydroxyl value of (440±5) mgKOH / g.

[0107] The bio-based branched polyol was cooled to 60°C, and 30 parts of 1,4-dioxane solvent were added and stirred to obtain a bio-based branched polyol (ED) solution for later use.

[0108] Step C2. Synthesize the intermediate IG solution.

[0109] Take 44.46 parts of isophorone diisocyanate (IPDI, 8.0 eq), 0.04 parts of dibutyltin dilaurate (DBTDL) catalyst and 50 parts of 1,4-dioxane solvent and put them into a three-necked flask, and heat to 40℃.

[0110] 11.85 parts of glycidol (10.0 eq) were added dropwise to the above reaction flask through a constant pressure dropping funnel over 30 minutes. The mixture was mechanically stirred, protected with nitrogen, and reacted in a constant temperature oil bath at 40°C for 5 hours to obtain the intermediate IG solution.

[0111] Step C3. Mix the bio-based branched polyol (ED) solution with the intermediate IG solution to synthesize the bio-based branched epoxy resin ED-IG8.

[0112] The IG solution obtained from step C2 was added dropwise to the reaction flask of step C1 over 45 minutes using a constant pressure dropping funnel. The temperature was raised to 60°C, and the reaction was carried out for 5 hours under nitrogen protection.

[0113] Then add 2 parts of anhydrous ethanol and continue the reaction for 30 minutes to ensure that all isocyanate groups react completely. Remove the solvent by rotary evaporation to obtain a brownish-yellow transparent viscous liquid product, namely bio-based branched epoxy resin ED-IG8.

[0114] The structure of the bio-based branched epoxy resin ED-IG8 synthesized by the above preparation method is similar to that of ED-IG12, so its structural characterization will not be described in detail.

[0115] Example 4

[0116] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG12, and an reactive diluent.

[0117] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0118] Example 5

[0119] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG12, and an reactive diluent.

[0120] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0121] Example 6

[0122] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG12, and an reactive diluent.

[0123] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0124] Example 7

[0125] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG12, and an reactive diluent.

[0126] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0127] Example 8

[0128] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific component composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG10, and an reactive diluent.

[0129] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0130] Example 9

[0131] A high-strength, high-toughness grouting material comprising an epoxy resin composition is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific composition is shown in Table 1. Component A comprises bisphenol A type epoxy resin, bio-based branched epoxy resin ED-IG8, and an reactive diluent.

[0132] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0133] Comparative Example 1

[0134] A bisphenol A type epoxy resin grouting material without bio-based branched epoxy resin is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific component composition is shown in Table 1. Component A consists of bisphenol A type epoxy resin and an reactive diluent. This comparative example differs from Example 8 only in its resin composition; the resin composition of Comparative Example 1 does not contain bio-based branched epoxy resin toughening agent.

[0135] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0136] Comparative Example 2

[0137] A bisphenol A type epoxy resin grouting material without bio-based branched epoxy resin is formed by uniformly mixing component A and component B in a mass ratio of 3:1. The specific component composition is shown in Table 1. Component A includes bisphenol A type epoxy resin and an reactive diluent. This comparative example differs from Example 9 only in its resin composition; the resin composition of Comparative Example 1 does not contain a bio-based branched epoxy resin toughening agent, but instead uses polyether diol-modified bisphenol F type epoxy resin as the toughening agent.

[0138] The curing conditions for the resin casting and bonded sample used in the grouting material test were as follows: the cured material was obtained by placing it in a standard laboratory at 23±2℃ for 14 days.

[0139]

[0140]

[0141] Table 1. Composition table of Examples 4-9 and Comparative Examples 1-2: Test results:

[0142] The resin compositions prepared in Examples 4-9 and Comparative Examples 1-2 were used to form cured grouting material samples, which were then left at room temperature for 24 hours before performance testing. The following are descriptions of the relevant test items.

[0143] (1) Infrared spectroscopy (FT-IR): The present invention uses a Bruker Tensor27 Fourier transform infrared spectrometer for measurement.

[0144] (2) Nuclear magnetic resonance (NMR) 1 H-NMR: The present invention uses a 400MHz nuclear magnetic resonance spectrometer from Bruker GmbH, Germany, with TMS as an internal standard and deuterated CDCl3 as a solvent.

[0145] (3) The initial viscosity was determined according to GB / T2794-1995. The initial viscosity of component A and component B after mixing was measured using an NDJ-8S rotational viscometer. The calculation results were accurate to 1 mPa·s.

[0146] (4) Working time: The time interval when the viscosity of the epoxy resin grouting material reaches 200 mPa·s after the two components are mixed is the working time.

[0147] (5) Tensile strength and elongation at break: Dumbbell-shaped tensile specimens were prepared in accordance with GB / T2567—2008 and tested using a micro-controlled electronic universal testing machine. The tensile rate was 2 mm / min and the calculation results were accurate to 1 MPa.

[0148] (6) Compressive strength: measured according to GB / T2569—1995, the specimen size is 2cm×2cm×2cm cube, and the calculation result is accurate to 1MPa.

[0149] (7) Tensile shear strength: determined according to GB / T7124—2008, using No. 45 steel sheet (100mm×25mm×2.5mm), after surface treatment, the mixed epoxy resin grouting material is evenly coated on the steel sheet, with a single-sided overlap length of 12.5mm, and after curing, it is tested with a universal testing machine, and the calculation result is accurate to 0.1MPa.

[0150] (8) Tensile shear strength after vibration fatigue: To evaluate the performance stability of the grouting material under long-term vibration conditions, steel-to-steel tensile shear specimens (bonded with grouting material) were prepared. After curing to the required age, the specimens were fixed on the vibration table of the ES-30-370 / LT0808 electromagnetic vibration generator and subjected to vibration tests. The vibration conditions were 5 Hz and 20 mm. The tensile shear strength of the specimens was tested after 14 days.

[0151] (9) Dry bond strength and wet bond strength: The test shall be conducted in accordance with the provisions of 7.9 of JC / T1041-2007 "Epoxy Resin Grouting Material for Concrete Cracks".

[0152] (10) Bending strength: determined according to GB / T2567—2008, a rectangular specimen with dimensions of 80mm×10mm×4mm was prepared, and the specimen was broken by three-point bending using a micro-controlled electronic universal testing machine with a loading rate of 5mm / min.

[0153] (11) Impact strength: The toughening effect of the material is characterized by impact strength. According to GB / T1043.1—2008 "Determination of impact performance of simply supported plastic beams" Part 1, the test is carried out using a digital display cantilever beam impact tester. The size of the unnotched specimen is 80mm×10mm×4mm.

[0154] (12) Ratio of anti-seepage pressure to osmotic pressure: The ratio shall be determined in accordance with the provisions of 7.10 of JC / T1041-2007 "Epoxy Resin Grouting Material for Concrete Cracks".

[0155] (13) Scanning electron microscopy (SEM) analysis: The fracture surface of the impact specimen was plated with gold to make it conductive and observed under a Hitachi S-4300 scanning electron microscope with an accelerating voltage of 15.0 kV.

[0156] The performance test results of the high-strength and high-toughness epoxy resin composition and its grouting material are shown in Table 2.

[0157]

[0158] Table 2. Performance test results of grouting materials formed from the resin compositions of Examples 4-9 and Comparative Examples 1-2

[0159] The high-strength, high-toughness epoxy resin compositions and grouting materials made from them provided in Examples 4-9 all use bio-based branched epoxy resin as toughening and modifying components.

[0160] As shown in Table 2, when the amount of bio-based branched epoxy resin added is in the range of 3%-12%, the mechanical properties of the grouting material exhibit a parabolic trend of first increasing and then decreasing. Specifically, when the addition amount is 9% (Example 8, ED-IG10), the overall performance of the cured product reaches the optimal level, with the specific performance indicators as follows:

[0161] Compressive strength: 89 MPa (25.3% higher than Comparative Example 1, 43.5% higher than Comparative Example 2);

[0162] Tensile strength: 47 MPa (93.1% higher than Comparative Example 1, and 74.3% higher than Comparative Example 2);

[0163] Elongation at break: 11.2% (128.6% higher than Comparative Example 1, and 28.7% higher than Comparative Example 2);

[0164] Tensile shear strength: 19.7 MPa (27.0% higher than Comparative Example 1, and 62.1% higher than Comparative Example 2);

[0165] Bending strength: 78 MPa (23.8% improvement compared to Comparative Example 1, and 50% improvement compared to Comparative Example 2);

[0166] Impact strength: 30.3 KJ / m 2 (111.9% higher than Comparative Example 1, and 76.2% higher than Comparative Example 2).

[0167] The above data shows that bio-based branched epoxy resin achieves a simultaneous increase in tensile strength and elongation at break of the cured grouting material (reaching 93.1% and 128.6%, respectively) through the synergistic effect of flexible molecular segments and multiple functional groups, proving that it has a synergistic enhancement effect of strength and toughness.

[0168] The grouting materials made from high-strength, high-toughness epoxy resin compositions in Examples 4-9 all meet the core industry standard requirements: initial viscosity < 200 mPa·s, workable time > 30 minutes, dry bond strength ≥ 4.0 MPa, wet bond strength ≥ 2.5 MPa, anti-seepage pressure ≥ 1.2 MPa, anti-seepage pressure ratio ≥ 400%, and the properties of the grout and cured product all meet the requirements of Type N, Grade II of JC / T1041-2007 "Epoxy Resin Grouting Materials for Concrete Cracks".

[0169] Furthermore, durability tests showed that Examples 5-9 passed a 14-day vibration fatigue test (approximately 6 × 10⁻⁶ vibration cycles). 6 After [number] cycles, the tensile shear strength retention rate is >69% (>9 MPa). Example 8 shows a tensile shear strength retention rate >80% (>15 MPa), while Comparative Examples 1 and 2 show a tensile shear strength retention rate <50% (<6 MPa). The material of this invention exhibits a significantly reduced strength decay rate under vibration conditions, meeting the long-term service requirements of subway tunnels and fundamentally solving the "re-leakage" problem.

[0170] The mechanical properties of the high-strength, high-toughness epoxy resin composition and its grouting material of the present invention are jointly determined by the crosslinking density and the toughening resin structure. The intramolecular non-crosslinked cavity structure of the bio-based branched epoxy resin can absorb impact energy and improve toughness, but excessive addition will weaken the interfacial bonding force due to cavity aggregation. Therefore, an appropriate crosslinking density can improve strength through chemical bonding, but an excessively high crosslinking density will restrict the movement of molecular chain segments, leading to brittle fracture. When the amount of epoxy resin composition added to the grouting material is 9%, the intramolecular cavity and crosslinking density reach a dynamic balance, achieving the optimal match between impact resistance and mechanical strength.

[0171] like Figure 6 , Figure 7 , Figure 8As shown, after impact fracture, the cured sample of grouting material without added bio-based branched epoxy resin showed a smooth fracture surface and a single crack propagation direction, exhibiting typical brittle fracture characteristics. However, after adding bio-based branched epoxy resin, the cured sample showed a large number of filamentous protrusions and fibrous cracks, with a complex fracture path, exhibiting ductile fracture, confirming that plastic deformation occurred before fracture.

[0172] like Figure 6 As shown, no obvious particle cavities or two-phase structure were found on the impact fracture surface of the material, indicating that the bio-based branched epoxy resin and bisphenol A type epoxy resin have excellent compatibility, forming a homogeneous structure after blending and curing. The bio-based branched epoxy resin is equivalent to organic particles uniformly dispersed in situ within the bisphenol A type epoxy resin, forming a homogeneous system. During curing, the epoxy groups around the bio-based branched epoxy resin molecules participate in the curing reaction.

[0173] Bio-based branched epoxy resins possess a branched structure, with no internal cross-linking and containing numerous free volumes such as cavities and defects. Introducing them into a bisphenol A type epoxy system for curing also introduces a large number of intramolecular and extramolecular free volumes. When the cured grouting material is subjected to external forces, these free volumes deform, forming… Figure 6 The numerous filamentous protrusions in the material can consume a large amount of energy during impact, thereby improving the toughness of the material. This is an in-situ toughening mechanism.

[0174] This invention, through the molecular design of bio-based branched epoxy resin (flexible segments + multiple epoxy functional groups + free volume) combined with innovative synthesis processes (low-temperature selective addition + controllable grafting), successfully overcomes the technical bottleneck of achieving both high strength and high toughness in epoxy grouting materials. Specifically, the bio-based branched epoxy resin, at an addition amount of 9% to the grouting material, achieves a dynamic balance between the cross-linked network and the toughening structure, with all performance characteristics exceeding the highest industry standard (N-type Class II). It exhibits particularly outstanding durability in the vibration environment of subways, providing key technical support for solving the problem of tunnel leakage re-emergence.

[0175] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy resin composition, characterized in that, The composition includes 70-75 parts of bisphenol A type epoxy resin, 3-12 parts of bio-based branched epoxy resin, and 18-22 parts of reactive diluent. Among them, bio-based branched polyols are synthesized under solvent-free conditions, and bio-based branched epoxy resins are synthesized after introducing polyurethane-epoxy intermediates containing epoxy groups into the bio-based branched polyols for modification.

2. The epoxy resin composition according to claim 1, characterized in that, The reactive diluent is one or more of phenyl glycidyl ether, o-tolyl glycidyl ether, benzyl glycidyl ether, and 1,4-butanediol diglycidyl ether.

3. The epoxy resin composition according to claim 1, characterized in that, The bisphenol A type epoxy resin is bisphenol A type epoxy resin E51.

4. The epoxy resin composition according to claim 1, characterized in that, The synthesis process of bio-based branched epoxy resin includes Step P1. Synthesize bio-based branched polyol ED solution: Epoxidized soybean oil, a polyfunctional alkyd compound, and an appropriate amount of catalyst are placed in a reaction apparatus. Under stirring and heating conditions, the epoxy groups of the epoxidized soybean oil and the active groups of the alkyd compound undergo a ring-opening addition reaction until the epoxy groups in the system are completely consumed. The resulting bio-based branched polyol is cooled to a suitable temperature and an appropriate amount of organic solvent is added for dispersion to form a homogeneous solution for later use. Step P2. Synthesis of intermediate IG solution: Aliphatic diisocyanate, catalyst and solvent are added to the reaction apparatus and heated to the set temperature. When the epoxy value is lower than 0.1%, an alcohol compound containing epoxy groups is slowly and evenly added dropwise to the reaction apparatus. Under the protection of an inert atmosphere, the alcohol compound containing epoxy groups undergoes a selective addition reaction with specific functional groups of diisocyanate to obtain epoxy functionalized intermediate IG solution. Step P3. Mix the bio-based branched polyol solution with the intermediate IG solution to synthesize the bio-based branched epoxy resin: The IG solution prepared in step P2 is slowly added to the ED solution in step P1 under controlled conditions. The reaction temperature is increased and the reaction is carried out under an inert atmosphere. After the reaction is completed, a small amount of end-capping agent is added to ensure that the residual isocyanate groups react completely. The solvent is removed by rotary evaporation to obtain the final product, namely the bio-based branched epoxy resin.

5. The epoxy resin composition according to claim 1, characterized in that, After synthesizing the bio-based branched polyol, the number of terminal epoxy groups carried on each molecule of the synthesized bio-based branched epoxy resin is controlled by adjusting the molar ratio of intermediate IG to the core of the synthesized bio-based branched polyol.

6. A grouting material, characterized in that, The composition includes component A and component B. Component A is any one of the epoxy resin compositions according to claims 1-6. Component B includes 18-25 parts of modified cycloaliphatic amine, 43-50 parts of polyether amine, 10-15 parts of isophorone diamine, 8-13 parts of m-phenylenediamine, 3-6 parts of accelerator, and 3-5 parts of aminosilane coupling agent.

7. A grouting material according to claim 6, characterized in that, Polyetheramine is a polyoxypropylene compound mainly composed of primary amino groups.

8. A grouting material according to claim 6, characterized in that, The aminosilane coupling agent is one or any two of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)γ-aminopropyltriethoxysilane coupling agent, and N-β-(aminoethyl)γ-aminopropyltrimethoxysilane coupling agent.

9. A grouting material according to claim 6, characterized in that, The accelerator is one or both of 2,4,6-tris(dimethylaminomethyl)phenol and triethylamine.

10. A grouting material according to claim 6, characterized in that, At room temperature, component A and component B are mixed evenly at a mass ratio of 3:1 to complete the preparation of the grouting material slurry; The grouting material is injected into the concrete cracks using a single-liquid grouting machine. The grouting material is then left at room temperature for several days to cure, resulting in a resin casting.

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