Liquid epoxy adhesive and method of making same

Abstract

The application relates to the technical field of building material waterproofing, and particularly discloses a liquid epoxy adhesive and a preparation method thereof.A liquid epoxy adhesive comprises an A component and a B component which are separately stored and mixed when used; the A component comprises the following raw materials in parts by weight: 90-100 parts of epoxy resin, 4-6 parts of carbon dodecyl to tetradecyl glycidyl ether and 8-12 parts of nonyl phenol; the B component comprises the following raw materials in parts by weight: 23-27 parts of polyether amine, 55-65 parts of nonyl phenol, 3.5-4.5 parts of N-aminoethyl piperazine and 3.5-4.5 parts of tri-(dimethylaminomethyl) phenol.The liquid epoxy adhesive obtained by the application can maintain high fluidity, realize rapid curing, and has excellent mechanical properties and heat resistance.

Description

Technical Field

[0001] This application relates to the field of waterproofing technology for building materials, and more specifically, to a liquid epoxy adhesive and its preparation method. Background Technology

[0002] Epoxy adhesives are widely used in electronics, aerospace, automotive, and construction industries due to their excellent bonding properties, chemical resistance, and mechanical strength. Particularly in waterproofing, anti-slip, and marking applications for infrastructure such as bridges and roads, extremely high requirements are placed on the adhesive's flowability, curing speed, and overall durability.

[0003] Currently, most epoxy adhesives on the market are solid or semi-solid, with poor flowability, making it difficult to meet the filling requirements of complex structures. In addition, existing epoxy adhesives have high curing temperatures, resulting in high energy consumption, and some products are prone to aging at high temperatures, affecting bonding reliability.

[0004] To address the aforementioned needs and shortcomings, existing technologies primarily employ the following improvement methods: (1) Adding diluents to reduce viscosity. By adding small molecule diluents (such as butyl glycidyl ether, phenyl glycidyl ether, etc.) to the epoxy resin system, the viscosity of the system can be effectively reduced and the fluidity improved. However, the addition of such conventional diluents often significantly reduces the mechanical properties of the cured product, such as tensile strength and adhesive strength, resulting in a decline in the overall performance of the adhesive.

[0005] (2) Use low-temperature curing agents to reduce the curing temperature. Using low-temperature curing agents such as aliphatic amines and polyamides can achieve curing at a lower temperature, thereby reducing energy consumption. However, these low-temperature curing agents usually have low reactivity, resulting in a longer curing time and affecting construction efficiency.

[0006] (3) Introducing heat-resistant fillers to improve heat resistance. Adding inorganic fillers such as silica, carbon fiber, and calcium carbonate to the system can improve the heat resistance and mechanical strength of the cured product. However, the introduction of fillers will increase the viscosity of the system, affect the workability, and when the interfacial bonding force between the filler and the resin matrix is ​​insufficient, it will become a stress concentration point, reducing the overall mechanical properties of the material.

[0007] (4) Development of single-component epoxy systems. Some existing technologies attempt to develop single-component latent epoxy adhesives by encapsulating or modifying the curing agent to prevent it from reacting at room temperature, releasing its activity only upon heating. While these products are convenient to use, they typically require high curing temperatures (>80℃) and have poor storage stability and short shelf life. Regarding the aforementioned technologies, the inventors believe that while adding diluents can improve flowability, it sacrifices the strength and heat resistance of the adhesive; low-temperature curing agents can reduce energy consumption, but have low curing efficiency; the introduction of heat-resistant fillers may lead to problems such as excessively high viscosity and difficult application; and single-component systems are limited by curing temperature and storage stability. Therefore, there is an urgent need to propose a solution to address these technical problems. Summary of the Invention

[0008] In order to achieve rapid curing, excellent mechanical properties and heat resistance while maintaining high fluidity, this application provides a liquid epoxy adhesive and its preparation method.

[0009] In a first aspect, this application provides a liquid epoxy adhesive, which adopts the following technical solution: A liquid epoxy adhesive comprising component A and component B, which are stored separately and mixed upon use: Component A comprises the following raw materials in parts by weight: 90-100 parts epoxy resin; 4-6 parts of C12-14-tetradecyl glycidyl ether; Nonylphenol 8-12 parts; Component B comprises the following raw materials in parts by weight: 23-27 parts of polyetheramine; Nonylphenol 55-65 parts; 3.5-4.5 parts of N-aminoethylpiperazine; 3.5-4.5 parts of tris-(dimethylaminomethyl)phenol.

[0010] By adopting the above technical solution, in component A, epoxy resin, as the matrix resin, mainly provides the main chain epoxy groups, which undergo ring-opening crosslinking with the amine curing agent in component B to form a three-dimensional crosslinking network. C12-C14 alkyl glycidyl ether can not only reduce the viscosity of component A and the mixed system, improve fluidity and wettability of the bonded surfaces, but also participate in the curing reaction and embed itself in the crosslinking network. Moreover, the long carbon chain side groups can moderately increase the flexibility of the cured product. Nonylphenol, as a nonionic surfactant and plasticizer, can also reduce the viscosity of the system and improve the flexibility and impact resistance of the cured product. Furthermore, the phenolic hydroxyl group has a significant catalytic promoting effect on the epoxy-amine curing reaction, which can accelerate the reaction rate, especially beneficial for low-temperature curing. In component B, polyetheramine mainly undergoes addition polymerization with epoxy resin to form crosslinking points, and the polyether backbone endows the cured product with high flexibility, impact resistance, and low-temperature toughness; nonylphenol acts as a curing accelerator and toughening agent; N-aminoethylpiperazine contains primary and secondary amines in its molecular structure, has high reactivity, and can increase the crosslinking density of the cured product, thereby improving hardness, heat resistance, and chemical resistance. Compared with polyetheramine, its reactivity is even higher, further accelerating the overall curing speed; tris-(dimethylaminomethyl)phenol can catalyze the reaction between epoxy groups and amine groups extremely effectively, and produces a synergistic catalytic effect with the phenolic hydroxyl group of nonylphenol, forming a powerful low-temperature promoting system that can significantly improve curing efficiency. The liquid epoxy adhesive formed by combining components A and B, through the combination of C12-14-alkyl glycidyl ether and nonylphenol, and the synergistic effect of compounded polyetheramine, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol, simultaneously meets the comprehensive requirements of high fluidity, rapid curing, excellent mechanical properties and heat resistance at both the molecular and component levels, ultimately resulting in a liquid epoxy adhesive with superior application quality.

[0011] Preferably, the raw material of component A also contains 5-10 parts by weight of functional additives, which are composed of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester, and the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is (2-3):1.

[0012] By adopting the above technical solution, furfuryl alcohol glycidyl ether further reduces the viscosity of component A, and synergistically improves fluidity with C12-14-decyl glycidyl ether. It can also participate in the epoxy-amine curing reaction, covalently bonding into the crosslinking network. Furthermore, the polar oxygen atoms of the furan ring can form hydrogen bonds or dipole interactions with the substrate surface, achieving rigid viscosity reduction and heat resistance compensation. The numerous terminal hydroxyl groups (-OH) of the hyperbranched polyester can undergo etherification reactions with epoxy groups or form strong hydrogen bonds with amine groups during curing, "pinning" themselves into the crosslinking network at multiple sites. Its three-dimensional branched spherical structure dispersed in the resin matrix can induce crack deflection, branching, and termination upon impact, consuming fracture energy and resulting in nano-toughening. Moreover, the branched molecules contain numerous free volume vacancies, which can absorb and disperse curing shrinkage stress and thermal stress. Simultaneously, its amphiphilic structure... (Polar hydroxyl groups + non-polar backbone) can act as a compatibilizer to promote uniform mixing between flexible segments and rigid crosslinking points, realizing the replacement of traditional inorganic heat-resistant fillers with "nano-hyperbranched polymers" and avoiding the problems of increased viscosity and weak interfacial bonding. When furfuryl alcohol glycidyl ether and terminal hydroxyl hyperbranched polyester are combined in a weight ratio of (2-3):1 to form a functional additive, a "rigid reactive diluent (furfuryl alcohol glycidyl ether)" is introduced at the molecular level to ensure heat resistance, reduce viscosity and participate in crosslinking. At the nano level, "terminated hydroxyl hyperbranched polyester" is introduced to achieve multi-point anchoring and crack inhibition toughening. After the two are compounded, without damaging the original high fluidity and fast curing ability, the adverse effects of the diluent on strength and heat resistance are effectively compensated, so that the liquid epoxy adhesive can obtain a comprehensive performance improvement of "low viscosity + fast curing + high strength / high toughness + good heat resistance".

[0013] Preferably, the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 2.4:1.

[0014] By adopting the above technical solution, within the range of 5-10 parts of total functional additive dosage, the above ratio is the preferred ratio that most significantly enhances the synergistic improvement of high fluidity, rapid curing, excellent mechanical properties and heat resistance, and has the best process implementation among the compounding ratios of this functional additive.

[0015] Preferably, the hydroxyl-terminated hyperbranched polyester has a molecular weight of 2000-4000 and a hydroxyl value of 150-250 mgKOH / g.

[0016] By adopting the above technical solution, this molecular weight range allows hyperbranched polyesters to be uniformly dispersed in epoxy resin at the nanoscale, without increasing the viscosity of the system, while possessing the effective particle size and spacing required to trigger crack deflection and branching. This hydroxyl value range ensures that the hyperbranched molecules have sufficient terminal hydroxyl groups, which can be anchored at multiple points in the epoxy-amine crosslinking network through hydrogen bonding or etherification reactions during the curing process, strengthening interfacial bonding and dissipating fracture energy, thereby significantly improving fracture toughness and impact resistance. At the same time, excessive hydroxyl groups will not cause matrix softening or moisture absorption and thickening. In this way, the terminal hydroxyl hyperbranched polyester maximizes its contribution to mechanical property enhancement and heat resistance compensation while maintaining high fluidity and rapid curing.

[0017] Preferably, the epoxy resin is a mixture of bisphenol F type epoxy resin and bisphenol A type epoxy resin, and the weight ratio of bisphenol F type epoxy resin to bisphenol A type epoxy resin is (3-5):1.

[0018] By adopting the above technical solution, using low-viscosity bisphenol F epoxy resin as the main component, the initial viscosity of component A and the mixed adhesive is significantly reduced. This, combined with the reactive diluent, achieves excellent high flowability and permeability to porous substrates. Furthermore, the epoxy functionality and equivalent of both components are similar, having no adverse effect on the rapid curing system of component B. The low viscosity even promotes uniform mixing and reaction diffusion. The aromatic ring skeletons of bisphenol F and bisphenol A together provide a high-strength rigid crosslinked matrix, exhibiting strong mechanical properties. Simultaneously, under the combined effect of the high crosslinking density of N-aminoethylpiperazine, the furan-based rigid reactive diluent, and the hydroxyl-terminated hyperbranched polyester, the cured product exhibits excellent glass transition temperature and heat aging resistance. Finally, a bisphenol F / bisphenol A epoxy blending ratio of (3–5):1 represents the optimal range that balances low viscosity for easy application with high strength and high heat resistance of the cured product.

[0019] Preferably, the weight ratio of bisphenol F epoxy resin to bisphenol A epoxy resin is 4.5:1.

[0020] By adopting the above technical solutions, the epoxy resin system can achieve the best balance between "minimizing viscosity and maintaining construction fluidity" and "using a small amount of bisphenol A resin to stabilize heat resistance and mechanical properties".

[0021] Preferably, the bisphenol F type epoxy resin has an epoxy equivalent of 162-175 g / eq and a viscosity of 2000-4500 mPa·s at 25°C; the bisphenol A type epoxy resin has an epoxy equivalent of 184-194 g / eq and a viscosity of 10000-15000 mPa·s at 25°C.

[0022] By adopting the above technical solution, the viscosity of bisphenol F epoxy resin is only 1 / 3 to 1 / 2 that of bisphenol A epoxy resin. Using it as a matrix can significantly reduce the viscosity of component A and the mixed adhesive, achieving excellent application flowability and substrate penetration in synergy with reactive diluents. Furthermore, the epoxy equivalents of both are close and within the typical range of liquid epoxy, making the average epoxy equivalent easy to calculate after mixing. The dosage of amine curing agent in component B is well-defined and has high tolerance for error. The low viscosity facilitates uniform mixing, and the room temperature / low temperature rapid curing characteristics are stable and reliable. Simultaneously, this... Both bisphenol F and bisphenol A epoxy resins form highly polymeric aromatic ring crosslinked networks after curing. A small amount of bisphenol A resin helps stabilize the modulus and batch strength reproducibility, and together with the curing agent system and functional additives, they construct a rigid-flexible-nano-toughening synergistic network. Finally, the high aromatic ring density of bisphenol F resin, combined with a small amount of isopropylidene groups of bisphenol A resin, a highly crosslinked density amine curing agent, a furan-based rigid reactive diluent, and the anchoring effect of hydroxyl-terminated hyperbranched polyester, results in better glass transition temperature and thermal aging performance of the cured product. Therefore, the above-mentioned bisphenol F / bisphenol A epoxy resin combinations with the specified epoxy equivalent and viscosity represent the optimal range of raw material specifications that balance low viscosity for easy application, accurate curing measurement, high strength, and heat resistance.

[0023] Preferably, the weight ratio of component A to component B when used in combination is 100:(29-31).

[0024] By adopting the above technical solutions, the optimal balance between workability, curing speed, mechanical strength and heat resistance of liquid epoxy adhesives can be ensured.

[0025] Secondly, this application provides a method for preparing a liquid epoxy adhesive, which adopts the following technical solution: A method for preparing a liquid epoxy adhesive includes the following steps: (1) Prepare the raw materials contained in component A according to the following proportions: epoxy resin, C12 to C14 alkyl glycidyl ether and nonylphenol; and the raw materials contained in component B: polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol.

[0026] (2) Preparation of component A: The corresponding epoxy resin, C12-14-tetradecyl glycidyl ether and nonylphenol were mixed and stirred to obtain the component A; Preparation of component B: The corresponding polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol were mixed and stirred to obtain the component B. (3) After mixing and stirring the components A and B obtained in step (2) in proportion, a liquid epoxy adhesive is obtained.

[0027] Thirdly, this application provides the application of a liquid epoxy adhesive in waterproof, anti-slip, or marking coatings for bridges or roads.

[0028] In summary, this application has the following beneficial effects: 1. This application achieves a liquid epoxy adhesive that maintains high fluidity while achieving rapid curing, excellent mechanical properties, and heat resistance by combining C12-tetradecyl glycidyl ether with nonylphenol and synergistically combining polyetheramine, N-aminoethylpiperazine, and tris-(dimethylaminomethyl)phenol. 2. This application uses a functional additive composed of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester. By introducing a "rigid reactive diluent (furfuryl alcohol glycidyl ether)" at the molecular level to ensure heat resistance, reduce viscosity and participate in crosslinking, and introducing "hydroxyl-terminated hyperbranched polyester" at the nano level to achieve multi-point anchoring and crack inhibition toughening, the combination of the two enables the liquid epoxy adhesive to achieve a comprehensive performance improvement of "low viscosity + fast curing + high strength / high toughness + good heat resistance". Detailed Implementation

[0029] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0030] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this application are commercially available.

[0031] Epoxy resin: purchased from Jiangsu Sanmu Chemical Co., Ltd.; C12-tetradecyl glycidyl ether: Model XY748, purchased from Anhui Xinyuan Technology Co., Ltd.; Polyetheramine and nonylphenol: Purchased from Shanghai Zhixi Trading Co., Ltd. N-Aminoethylpiperazine: Specification AEP-HP, purchased from Dalian Liansheng Trading (Suzhou) Co., Ltd.; Tri-(dimethylaminomethyl)phenol: purchased from Changzhou Yourui Polymer Materials Co., Ltd. Example Example 1

[0032] A liquid epoxy adhesive comprising component A and component B, which are stored separately and mixed upon use, and is prepared by the following steps: (1) Prepare the raw materials contained in component A according to the following proportions: epoxy resin, C12 to C14 alkyl glycidyl ether and nonylphenol; and the raw materials contained in component B: polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol.

[0033] (2) Preparation of component A: The corresponding epoxy resin, C12-tetradecyl glycidyl ether and nonylphenol were mixed and stirred at 45°C and 300 rpm for 25 min to obtain the following: Preparation of component B: The corresponding polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol were mixed and stirred at 25°C and 150 rpm for 10 min to obtain the following: (3) Mix component A and component B obtained in step (2) in proportion and stir at 200 rpm for 3 min to obtain liquid epoxy adhesive.

[0034] Note: In the above operations, the raw materials and corresponding weight parts of component A are shown in Table 1, and the raw materials and corresponding weight parts of component B are shown in Table 2. The weight ratio of component A to component B when used in combination is 100:30. The epoxy resin is a mixture of bisphenol F type epoxy resin and bisphenol A type epoxy resin, and the weight ratio of bisphenol F type epoxy resin to bisphenol A type epoxy resin is 4.5:1. Among them, the epoxy equivalent of bisphenol F type epoxy resin is 168.5 g / eq, and the viscosity at 25℃ is 3250 mPa·s; the epoxy equivalent of bisphenol A type epoxy resin is 189 g / eq, and the viscosity at 25℃ is 12500 mPa·s.

[0035] Example 2-3 A liquid epoxy adhesive, which differs from Example 1 in that the raw materials and corresponding weight parts of component A are shown in Table 1.

[0036] Table 1. Composition of Component A in Examples 1-3 and corresponding weight parts (parts / kg) Epoxy resin 95 90 100 C12-tetradecyl glycidyl ether 5 4 6 Nonylphenol 10 8 12 Examples 4-5 A liquid epoxy adhesive, which differs from Example 1 in that the raw materials and corresponding weight parts of component B are shown in Table 2.

[0037] Table 2. Composition of component B and corresponding weight parts (parts / kg) in Examples 1 and 4-5 polyetheramine 25 23 27 Nonylphenol 60 55 65 N-Aminoethylpiperazine 4 3.5 4.5 Tri-(dimethylaminomethyl)phenol 4 3.5 4.5 Example 6

[0038] A liquid epoxy adhesive, which differs from Example 1 in that the weight ratio of component A to component B when used in combination is 100:29. Example 7

[0039] A liquid epoxy adhesive, which differs from Example 1 in that the weight ratio of component A to component B when used in combination is 100:31. Example 8

[0040] A liquid epoxy adhesive, which differs from Example 1 in that the weight ratio of bisphenol F epoxy resin to bisphenol A epoxy resin is 4:1. Example 9

[0041] A liquid epoxy adhesive, which differs from Example 1 in that the weight ratio of bisphenol F epoxy resin to bisphenol A epoxy resin is 3:1. Example 10

[0042] A liquid epoxy adhesive, which differs from Example 1 in that the weight ratio of bisphenol F epoxy resin to bisphenol A epoxy resin is 5:1. Example 11

[0043] A liquid epoxy adhesive differs from Example 1 in that the bisphenol F epoxy resin has an epoxy equivalent of 162 g / eq and a viscosity of 2000 mPa·s at 25°C, while the bisphenol A epoxy resin has an epoxy equivalent of 184 g / eq and a viscosity of 10000 mPa·s at 25°C. Example 12

[0044] A liquid epoxy adhesive differs from Example 1 in that the bisphenol F type epoxy resin has an epoxy equivalent of 175 g / eq and a viscosity of 4500 mPa·s at 25°C, while the bisphenol A type epoxy resin has an epoxy equivalent of 194 g / eq and a viscosity of 15000 mPa·s at 25°C. Example 13

[0045] A liquid epoxy adhesive differs from Example 1 in that 7.5 parts by weight of a functional additive are added to the raw material of component A. The functional additive is composed of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester, and the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 2.4:1. At the same time, the molecular weight of the hydroxyl-terminated hyperbranched polyester is 3000 and the hydroxyl value is 200 mgKOH / g. Example 14

[0046] A liquid epoxy adhesive, which differs from Example 13 in that the functional additives are added in 5 parts by weight. Example 15

[0047] A liquid epoxy adhesive, which differs from Example 13 in that the functional additives are added in 10 parts by weight. Example 16

[0048] A liquid epoxy adhesive, differing from Example 13 in that the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 2.5:1. Example 17

[0049] A liquid epoxy adhesive, differing from Example 13 in that the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 2:1. Example 18

[0050] A liquid epoxy adhesive, differing from Example 13 in that the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 3:1. Example 19

[0051] A liquid epoxy adhesive, which differs from Example 13 in that the hydroxyl-terminated hyperbranched polyester has a molecular weight of 2000 and a hydroxyl value of 150 mg KOH / g. Example 20

[0052] A liquid epoxy adhesive, which differs from Example 13 in that the hydroxyl-terminated hyperbranched polyester has a molecular weight of 4000 and a hydroxyl value of 250 mg KOH / g. Example 21

[0053] A liquid epoxy adhesive, which differs from Example 13 in that furfuryl alcohol glycidyl ether is not used in component A. Example 22

[0054] A liquid epoxy adhesive, which differs from Example 13 in that hydroxyl-terminated hyperbranched polyester is not used in component A. Example 23

[0055] A liquid epoxy adhesive, which differs from Example 13 in that the hydroxyl-terminated hyperbranched polyester has a molecular weight of 1800 and a hydroxyl value of 140 mg KOH / g. Example 24

[0056] A liquid epoxy adhesive, which differs from Example 13 in that the hydroxyl-terminated hyperbranched polyester has a molecular weight of 1200 and a hydroxyl value of 260 mg KOH / g. Comparative Example

[0057] Comparative Example 1 A liquid epoxy adhesive, which differs from Example 1 in that no C12 to C14-tetradecyl glycidyl ether is used in component A.

[0058] Comparative Example 2 A liquid epoxy adhesive, which differs from Example 1 in that N-aminoethylpiperazine is not used in component B.

[0059] Comparative Example 3 A liquid epoxy adhesive, which differs from Example 1 in that tris-(dimethylaminomethyl)phenol is not used in component B.

[0060] Comparative Example 4 A liquid epoxy adhesive, which differs from Example 1 in that component A does not use C12 to C14-tetradecyl glycidyl ether, and component B does not use N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol. Performance testing

[0061] Test samples: The liquid epoxy adhesives obtained in Examples 1-24 were selected as test samples 1-24, and the liquid epoxy adhesives obtained in Comparative Examples 1-4 were selected as control samples 1-4.

[0062] Test methods: (1) High fluidity test, refer to GB / T 2794-2013 "Method for determination of viscosity of adhesives", use a rotational viscometer to test the viscosity at a temperature of 25℃; (2) Gel time test, which refers to the time it takes for the glue to lose its fluidity and form an initial cross-linked network (cannot be drawn into threads / cannot flow). In an environment with a temperature of 23℃ and a relative humidity of 50%, the probe drawing method is used. The probe is inserted vertically into the glue and then lifted. If the glue flows smoothly or the thin threads are drawn continuously, it is not gelled. If the glue no longer forms continuous threads when the probe is lifted, and there is obvious "break / rebound" in the container, and the surface no longer flows, the time at this time is the gel time. (3) Mechanical property testing, mainly tensile strength (ASTM D638), tensile elongation (ASTM D638), adhesive strength (ASTM C882) and compressive strength (ASTM D695) after 7 days of curing; (4) Heat resistance test: For heat adaptability (ASTM C884), a 50×50×50mm C40 concrete cube was selected, with a bonding surface of 50×50 mm. Adhesive was applied to the bonding surface with a thickness of 1mm. It was cured at 23℃ and RH 50% for 7 days and subjected to 10 heat cycles from −20℃ to 60℃ (each holding for 1.5 h, heating / cooling 5℃ / min). Pull-out tests were performed before and after the cycles, and the bond strength retention rate after the heat cycles was calculated.

[0063] After performing the above tests on test samples 1-24 and control samples 1-4, the test results are recorded in Table 3.

[0064] Table 3 Test results of test samples 1-24 and control samples 1-4 Test sample 1 1500 25.2 15.5 42.3 16.7 33.8 87.6 Test sample 2 1523 26.5 14.5 41.3 15.8 32.8 86.6 Test sample 3 1517 26.3 14.8 41.6 16.0 33.0 86.9 Test sample 4 1531 27.2 14.1 40.9 15.2 32.4 86.2 Test sample 5 1515 26.0 14.9 41.7 16.1 33.1 87.0 Test sample 6 1528 26.9 14.2 41.1 15.5 32.6 86.4 Test sample 7 1508 25.5 15.2 42.0 16.4 33.5 87.3 Test sample 8 1533 27.4 14.0 40.8 15.1 32.2 86.1 Test sample 9 1521 26.3 14.6 41.4 15.9 32.9 86.7 Test sample 10 1536 27.7 13.9 40.7 15.0 32.1 86.0 Test sample 11 1525 26.7 14.4 41.2 15.7 32.7 86.5 Test sample 12 1512 25.8 15.0 41.8 16.2 33.2 87.1 Test sample 13 1513 25.9 17.6 45.9 19.5 36.9 90.8 Test sample 14 1522 26.4 17.2 45.4 19.2 36.6 90.5 Test sample 15 1529 27.0 16.9 45.1 18.8 36.2 90.1 Test sample 16 1516 26.1 17.4 45.7 19.3 36.7 90.6 Test sample 17 1534 27.5 16.8 45.0 18.7 36.1 90.0 Test sample 18 1520 26.2 17.3 45.5 19.1 36.5 90.4 Test sample 19 1526 26.8 17.0 45.2 18.9 36.3 90.2 Test sample 20 1524 26.6 17.1 45.3 19.0 36.4 90.3 Test sample 21 1572 24.8 16.1 43.4 17.6 34.8 88.0 Test sample 22 1548 29.3 16.0 43.2 17.4 34.6 88.6 Test sample 23 1519 26.5 16.3 43.8 18.0 35.2 89.3 Test sample 24 1530 27.1 16.5 44.1 18.3 35.6 89.6 Control sample 1 1613 37.2 11.2 35.4 12.7 25.8 78.9 Control sample 2 1689 34.1 11.7 36.2 13.0 26.8 80.3 Control sample 3 1693 34.6 12.0 36.8 13.5 27.6 80.9 Control sample 4 1726 38.7 10.2 34.1 11.9 24.6 77.3 Combining Examples 1-12 and Comparative Examples 1-4 with Table 3, it can be seen that by combining dodecyl tetradecyl glycidyl ether with nonylphenol, and by synergistically combining polyetheramine, N-aminoethylpiperazine, and tris-(dimethylaminomethyl)phenol, the resulting liquid epoxy adhesive achieves rapid curing, excellent mechanical properties, and heat resistance while maintaining high fluidity. It was also found that the absence of dodecyl tetradecyl glycidyl ether in component A, or the absence of N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol in component B, resulted in significant losses in the viscosity (mPa•s), gelation time (min), tensile strength (MPa), tensile elongation (%), adhesive strength (MPa), compressive strength (MPa), and adhesive strength retention rate (%) obtained in the above tests.

[0065] Combining Examples 1 and 13-18 with Table 3, it can be seen that using functional additives composed of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester, through their compounding, effectively compensates for the adverse effects of diluents on strength and heat resistance without compromising the original high fluidity and rapid curing ability, resulting in a comprehensive performance improvement of "low viscosity + rapid curing + high strength / high toughness + good heat resistance" for liquid epoxy adhesives. If either furfuryl alcohol glycidyl ether or hydroxyl-terminated hyperbranched polyester is used alone, it is found that its improvement effect on mechanical properties and heat resistance is limited, and it adversely affects high fluidity and rapid curing performance. Meanwhile, judging from the performance of tensile strength (MPa), tensile elongation (%), adhesive strength (MPa), compressive strength (MPa), and adhesive strength retention rate (%), the combination of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester can bring a significant improvement effect of 1+1>2. Moreover, significant and excellent improvement effects can only be achieved when the molecular weight of the hydroxyl-terminated hyperbranched polyester is 2000-4000 and the hydroxyl value is 150-250 mgKOH / g. When it exceeds the above range, the corresponding effects will be greatly reduced.

[0066] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A liquid epoxy adhesive, characterized in that, This includes components A and B, which are stored separately and mixed when used: Component A comprises the following raw materials in parts by weight: 90-100 parts epoxy resin; 4-6 parts of C12-14-tetradecyl glycidyl ether; Nonylphenol 8-12 parts; Component B comprises the following raw materials in parts by weight: 23-27 parts of polyetheramine; Nonylphenol 55-65 parts; 3.5-4.5 parts of N-aminoethylpiperazine; 3.5-4.5 parts of tris-(dimethylaminomethyl)phenol.

2. The liquid epoxy adhesive according to claim 1, characterized in that: The raw materials of component A also contain 5-10 parts by weight of functional additives, which are composed of furfuryl alcohol glycidyl ether and hydroxyl-terminated hyperbranched polyester, and the weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is (2-3):

1.

3. The liquid epoxy adhesive according to claim 2, characterized in that: The weight ratio of furfuryl alcohol glycidyl ether to hydroxyl-terminated hyperbranched polyester is 2.4:

1.

4. The liquid epoxy adhesive according to claim 2, characterized in that: The hydroxyl-terminated hyperbranched polyester has a molecular weight of 2000-4000 and a hydroxyl value of 150-250 mgKOH / g.

5. The liquid epoxy adhesive according to claim 1, characterized in that: The epoxy resin is a mixture of bisphenol F type epoxy resin and bisphenol A type epoxy resin, and the weight ratio of bisphenol F type epoxy resin to bisphenol A type epoxy resin is (3-5):

1.

6. The liquid epoxy adhesive according to claim 5, characterized in that: The weight ratio of bisphenol F epoxy resin to bisphenol A epoxy resin is 4.5:

1.

7. The liquid epoxy adhesive according to claim 5, characterized in that: The bisphenol F type epoxy resin has an epoxy equivalent of 162-175 g / eq and a viscosity of 2000-4500 mPa·s at 25℃; the bisphenol A type epoxy resin has an epoxy equivalent of 184-194 g / eq and a viscosity of 10000-15000 mPa·s at 25℃.

8. The liquid epoxy adhesive according to claim 1, characterized in that: The weight ratio of component A to component B when used in combination is 100:(29-31).

9. The method for preparing the liquid epoxy adhesive according to claim 1, characterized in that: Includes the following steps: (1) Prepare the raw materials contained in component A according to the following proportions: epoxy resin, C12 to C14 alkyl glycidyl ether and nonylphenol; and the raw materials contained in component B: polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol: (2) Preparation of component A: The corresponding epoxy resin, C12-14-tetradecyl glycidyl ether and nonylphenol were mixed and stirred to obtain the component A; Preparation of component B: The corresponding polyetheramine, nonylphenol, N-aminoethylpiperazine and tris-(dimethylaminomethyl)phenol were mixed and stirred to obtain the component B. (3) After mixing and stirring the components A and B obtained in step (2) in proportion, a liquid epoxy adhesive is obtained.

10. The use of a liquid epoxy adhesive as described in any one of claims 1-8 in a waterproof, anti-slip, or marking coating for bridges or roads.