Normal-temperature curing type super high-strength epoxy splice adhesive and preparation method thereof
By compounding epoxy resin with toughening agents and using hyperbranched epoxy-polyurethane hybrids and composite curing agents, the problems of insufficient strength and poor construction compatibility of epoxy splicing adhesives at room temperature have been solved, resulting in an epoxy splicing adhesive with ultra-high strength and weather resistance, suitable for splicing and reinforcement of ultra-high performance concrete structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CNBM ZHONGYAN TECH
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-05
AI Technical Summary
Existing epoxy splicing adhesives are difficult to achieve ultra-high strength at room temperature and have poor construction compatibility, resulting in poor stress transfer between the adhesive layer and the ultra-high performance concrete substrate, which can easily lead to adhesive layer damage and limit the structural load-bearing potential and durability.
By combining epoxy resins with different functionalities and toughening agents, along with hyperbranched epoxy-polyurethane hybrids and composite curing agents, room temperature curing and high strength are achieved by controlling the structural toughness and crosslinking network density of the cured product. Reinforcing materials such as steel fibers are added to improve the mechanical properties and weather resistance of the adhesive layer.
It achieves ultra-high compressive strength and good thixotropy at room temperature, effectively transfers stress, improves the mechanical properties and weather resistance of the adhesive layer, and meets the construction requirements of ultra-high performance concrete structures.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete bonding and reinforcement technology, and in particular to a room-temperature curing ultra-high strength epoxy bonding adhesive and its preparation method. Background Technology
[0002] As the height of concrete towers increases, the strength of concrete segments also increases, leading to higher strength requirements for the epoxy splicing adhesive used in assembly. Currently, in the offshore wind power sector, ultra-high-strength concrete segments (compressive strength ≥150MPa) are being used, which poses significant challenges to epoxy splicing adhesives. The mechanical properties of splicing joints have become a key bottleneck restricting the overall structure from fully utilizing the material's advantages.
[0003] The compressive strength of ordinary epoxy splicing adhesives is generally in the range of 70-100MPa, which is far lower than the strength of ultra-high performance concrete (UHPC). This performance difference means that when the splicing joint is under stress, the stress cannot be effectively transferred between the adhesive layer and the UHPC substrate, which can easily lead to the adhesive layer failing first (such as crushing or cracking). This not only limits the load-bearing potential of the UHPC structure, but may also induce joint durability failure (such as moisture seeping into the interior through cracks in the adhesive layer).
[0004] While some high-strength epoxy materials (such as special grouting materials and repair materials) exist in existing technologies, with compressive strengths approaching 130-140 MPa, these materials suffer from significant construction adaptability defects: they either require high-temperature curing above 120°C (which cannot meet the requirements of on-site construction at normal temperatures), or have poor workability (such as uncontrolled fluidity and easy sagging during facade construction), or cure too quickly (the applicable period is less than 30 minutes, making it difficult to complete large-area splicing operations). None of these meet the actual working conditions of on-site facade splicing of ultra-high performance concrete segments. More importantly, the epoxy room-temperature curing system itself has technical bottlenecks. Room temperature curing relies on highly reactive chemical components (such as aliphatic amines and modified amines) to trigger cross-linking reactions at ambient temperatures (5-35℃). However, due to the limitations of reaction kinetics, such systems are difficult to achieve the theoretical degree of complete cross-linking. The molecular network is prone to forming micro-defects (such as unreacted active groups and micropores), which not only directly limits the upper limit of the mechanical properties of the adhesive layer (especially compressive strength and elastic modulus), but also leads to insufficient weather resistance and humid heat stability. Long-term exposure to the outdoors can easily cause yellowing and mechanical property degradation. In high temperature and high humidity environments, moisture is more likely to penetrate the adhesive layer and erode the adhesive-substrate interface. In some cases, the bonding strength may decrease by more than 30% after 1000 hours of humid heat aging. Summary of the Invention
[0005] To address the problems in the prior art, this invention provides a room-temperature curing ultra-high strength epoxy splicing adhesive and its preparation method. By compounding epoxy resins with different functionalities and toughening agents, and by controlling the structural toughness and crosslinking network density of the cured product, the mechanical properties of the epoxy splicing adhesive are significantly improved. Furthermore, the epoxy splicing adhesive obtained in this application can cure at room temperature, has ultra-high compressive strength, and exhibits good thixotropic properties for construction, and can be widely used in the splicing, repair, and reinforcement of ultra-high performance concrete components.
[0006] The first aspect of this invention is to provide a room-temperature curing ultra-high strength epoxy bonding adhesive, which adopts the following technical solution: A room-temperature curing ultra-high strength epoxy splicing adhesive includes a resin system, a curing agent system, and a reinforcing material. The weight ratio of the resin system to the curing agent system is (2.8-3.2):1, and the weight ratio of the resin system to the reinforcing material is (10-5):1. The resin system includes the following raw materials in parts by weight: 15-20 parts of composite epoxy resin, 3-5 parts of multifunctional reactive diluent, 1-2 parts of epoxy coupling agent, 3-5 parts of toughening agent, 1-2 parts of defoamer, 2-5 parts of wetting and dispersing agent, and 40-80 parts of filler. The curing agent system comprises the following raw materials in parts by weight: 15-30 parts of composite curing agent, 0.5-2 parts of amino-terminated polyether D-230, 1-1.5 parts of 1,4-butanediol, 0.1-0.5 parts of diethanolamine, 1-2 parts of antioxidant, 3-5 parts of accelerator, and 30-83 parts of filler; The reinforcing material is steel fiber.
[0007] By adopting the above technical solution, the epoxy splicing adhesive can be cured at room temperature, solving the problems of existing high-strength epoxy materials requiring high-temperature curing and poor construction compatibility. Through the reasonable ratio of resin system, curing agent system and reinforcing materials, the stress at the splicing joint can be effectively transferred between the adhesive layer and the ultra-high performance concrete substrate, avoiding the adhesive layer from failing first, and improving the load-bearing potential and joint durability of the ultra-high performance concrete structure. It overcomes the technical bottleneck of epoxy room-temperature curing system and improves the upper limit of the mechanical properties, weather resistance and humid heat stability of the adhesive layer.
[0008] Preferably, the composite epoxy resin comprises the following raw materials in parts by weight: 5-10 parts of bisphenol A type NPEL-128 epoxy resin, 5-10 parts of bisphenol F type NPEF-170 epoxy resin, 5-10 parts of low viscosity modified phenolic EPALLOY 8240 epoxy resin, 5-10 parts of tetraglycidylamine type modified EPM-420 epoxy resin, and 10-15 parts of hyperbranched epoxy-polyurethane hybrid.
[0009] By adopting the above technical solution, the addition of hyperbranched epoxy-polyurethane to epoxy resin firstly achieves a "rigid-toughness" balance in bulk toughening. The hyperbranched polyurethane skeleton, acting as a microscopic "elastomer," is uniformly dispersed within the rigid epoxy resin network. When the material is subjected to impact or stress, these flexible regions can effectively absorb and dissipate energy through the extension, rotation, and cavitation of molecular chains. Secondly, as a highly efficient "rheology modifier," it reduces entanglement and friction between molecular chains, improving the processability of highly filled systems. Furthermore, it increases crosslinking density and improves network uniformity; the numerous epoxy groups carried on its periphery become additional crosslinking points during curing. Unlike the dense but potentially brittle networks formed by traditional small-molecule curing agents, the crosslinking points of the hyperbranched epoxy-polyurethane hybrid are connected by flexible long chains, exhibiting better ductility and resistance to microcracks. Finally, it has a potential "interface-assisted compatibilization" effect; the polyurethane segments in its structure have a certain affinity for toughening agents and fillers.
[0010] Preferably, the hyperbranched epoxy-polyurethane hybrid is obtained by the following preparation method: after reacting NCO-terminated polyurethane prepolymer and chain extender, epichlorohydrin is added, and an epoxidation reaction is carried out under alkaline conditions to obtain the hyperbranched epoxy-polyurethane hybrid.
[0011] Preferably, the bisphenol A type NPEL-128 epoxy resin has an epoxy equivalent of 185-186.6 g / eq and a viscosity of 12000-15000 cps / 25℃; the bisphenol F type NPEF-170 epoxy resin has an epoxy equivalent of 163-169 g / eq and a viscosity of 2500-6000 cps / 25℃; the low viscosity modified phenolic EPALLOY 8240 epoxy resin has an epoxy equivalent of 155-175 g / eq and a viscosity of 6000-8000 cps / 25℃; and the tetraglycidylamine type modified EPM-420 epoxy resin has an epoxy equivalent of 110-125 g / eq and a viscosity of 8000-12000 cps / 25℃.
[0012] By adopting the above technical solutions, bisphenol A type NPEL-128 epoxy resin possesses certain epoxy equivalent and viscosity, providing basic mechanical and adhesive properties; bisphenol F type NPEF-170 epoxy resin has relatively low viscosity, which improves the fluidity of the system and facilitates construction; low-viscosity modified phenolic EPALLOY 8240 epoxy resin can further adjust the system viscosity and enhance chemical corrosion resistance; tetraglycidylamine type modified EPM-420 epoxy resin has multifunctionality, which can increase the crosslinking density of the molecular network and improve the compressive strength and elastic modulus of the adhesive layer. The combined use of these four resins can optimize the comprehensive performance of room-temperature curing ultra-high strength epoxy splicing adhesive, making the epoxy splicing adhesive have suitable viscosity, high anti-crystallization properties, and meet the construction requirements in long-term storage or low-temperature environments. It also possesses excellent properties such as high heat resistance and corrosion resistance, meeting the actual working conditions of on-site vertical splicing of ultra-high performance concrete segments. Preferably, the composite curing agent comprises the following raw materials in parts by weight: 5-10 parts of alicyclic amine MFA-50 curing agent, 1-5 parts of aromatic diisocyanate, 5-10 parts of aromatic diamine DDS curing agent, 1-5 parts of aromatic amine DMTDA curing agent, and 5-10 parts of bismaleimide modifier WDDM521 curing agent.
[0013] Preferably, the cycloaliphatic amine MFA-50 curing agent has an amine value of 500-550 mg KOH / g and a viscosity of 200-600 mPa·s (cP) at 25°C; the aromatic diisocyanate MDI-100 has an NCO content >19% and a viscosity of 500 mPa·s (cP) at 25°C; the aromatic diamine DDS curing agent has an amine value of 890-925 mg KOH / g and a viscosity of 20000-50000 mPa·s (cP) at 25°C; the aromatic amine DMTDA curing agent has an amine value of 525-535 mg KOH / g and a viscosity of 500-800 mPa·s (cP) at 20°C; and the bismaleimide modifier WDDM521 curing agent has an amine value of 185-225 mg KOH / g and a viscosity of 4500-12000 mPa·s (cP) at 40°C.
[0014] By adopting the above technical solutions, the composite curing agent system enables room-temperature curing ultra-high strength epoxy splicing adhesive to simultaneously obtain the advantages of various curing agents on the construction site. Among them, the alicyclic amine MFA-50 curing agent has moderate reactivity, ensuring that it can effectively trigger the ring-opening crosslinking of epoxy groups at room temperature. Its mild exothermic reaction characteristics are conducive to the orderly arrangement of molecular chains, significantly reducing the formation of curing defects such as micropores and cracks, thereby greatly improving the density, water resistance and long-term outdoor weather resistance of the adhesive layer. The isocyanate groups (-NCO) in the aromatic diisocyanate precisely select to undergo addition reactions with the hydroxyl groups (-OH) on the surface of the resin system and modified fillers, generating in situ segments containing flexible urethane bonds in the rigid epoxy network. These "molecular springs" form an interpenetrating network structure through micro-phase separation, enabling the material to absorb energy through segment deformation when subjected to impact and vibration loads, increasing the fracture toughness to 2-3 times that of ordinary epoxy systems. The aromatic diamine DDS curing agent, with its high functionality and rigid benzene ring structure, can achieve high strength at 8°C. The post-curing stage above 0℃ forms a three-dimensional network skeleton with high cross-linking density, enabling the adhesive layer to achieve ultra-high compressive strength and elastic modulus, while increasing the glass transition temperature to ensure the dimensional stability and load-bearing capacity of the structure in high-temperature environments. The unique thioether bonds in the aromatic amine DMTDA curing agent molecule provide chain segment rotational freedom, introducing moderate flexibility into the rigid network constructed by DDS, effectively dispersing stress and inhibiting crack propagation. At the same time, its reactivity is between that of alicyclic amines and DDS, optimizing the network gradient across the entire temperature range and achieving a balance between high modulus and high toughness. The bismaleimide modifier WDDM521 undergoes a Michael addition reaction with amines through its maleimide double bonds and undergoes self-polymerization above 160℃ to form an ultra-rigid heat-resistant network rich in imide rings. This network synergistically interpenetrates with the epoxy-polyurethane system, further improving the comprehensive mechanical properties and heat resistance of the adhesive layer. Relying on the synergistic effect of this composite curing agent, epoxy splicing adhesive can complete rapid cross-linking and continuously optimize the molecular network structure at room temperature. After curing, it not only has high mechanical strength and durability, but also can adapt to the harsh construction conditions of on-site vertical splicing of ultra-high performance concrete segments, effectively breaking through the technical bottlenecks of existing epoxy room temperature curing systems in terms of early strength and long-term weather resistance.
[0015] Preferably, the fillers in both the resin system and the curing agent system are obtained using the following modification method: S1. Ethanolamine and 1,4-butanediol are mixed and dissolved in propylene glycol methyl ether. After stirring and mixing at 80±2℃, an activation solution is obtained. The activation solution is added dropwise to the packing material. The mixture is then mixed evenly with the packing material using a horizontal ribbon mixer. The reaction time is 35-40 minutes to obtain the activated packing material. S2. According to the molar ratio of NCO:-NH2 of 2.1:1, the terminal amino polyether and isocyanate were reacted at 60±2℃ for 60-90 min to obtain the prepolymer, and the NCO content was monitored by di-n-butylamine titration to ensure it reached the theoretical value. S3. After mixing the prepolymer and activated filler, disperse them evenly under high shear, and then heat them to 80±2℃ at a rate of 1-2℃ / min. Continue the reaction at this temperature for 110±10 minutes to obtain the modified filler.
[0016] By adopting the above technical solution, after the activation liquid made of ethanolamine and 1,4-butanediol is sprayed into the filler for reaction, a primary hydrogen bond layer is formed on the surface of the filler. Then, when the NCO-terminated prepolymer is added, the NCO groups at both ends can react with the filler and the resin matrix. The NCO-terminated prepolymer reacts with the amine or hydroxyl groups on the activation layer of the filler surface, anchoring the polyether segments in the prepolymer to the filler surface through chemical bonds. This results in the filler surface being coated with a flexible polymer, improving the dispersion stability and uniformity of the filler in the resin system and curing agent system.
[0017] Preferably, the fillers in the resin system include corundum, calcined quartz sand, nano-silica and titanium dioxide in a weight ratio of (2-4):(2-5):(0-0.5):(0-0.1).
[0018] Preferably, the particle size of the corundum is 800 mesh, and the particle size of the calcined quartz sand is 60-120 mesh.
[0019] Preferably, the fillers in the curing agent system include corundum, calcined alumina powder, nano-silica and carbon black in a weight ratio of (2-6):(1-2):(0-0.2):(0-0.1).
[0020] Preferably, the particle size of the corundum is 60-120 mesh, and the particle size of the calcined alumina powder is 1000 mesh.
[0021] A second aspect of the present invention is to provide a method for preparing a room-temperature curing ultra-high strength epoxy bonding adhesive as described above, comprising the following steps: S1. Preparation of resin system: Mix the raw materials in the composite epoxy resin at 60°C, stir evenly, add multifunctional active diluent, toughening agent, filler and epoxy coupling agent, heat the system to 80°C, disperse at high speed for 30 min, cool to 50°C, add defoamer and wetting and dispersing agent, stir at low speed for 20 min, and degas under vacuum for 30 min to obtain multiphase resin system; S2. Preparation of curing agent system: Composite curing agents include alicyclic amine MFA-50 curing agent, aromatic diisocyanate, aromatic diamine DDS curing agent, aromatic amine DMTDA curing agent, and bismaleimide modifier WDDM521 curing agent. S2.1. Aromatic diisocyanate is reacted with amino-terminated polyether D-230, 1,4-butanediol and diethanolamine at 80°C for 2-3 hours, and samples are taken periodically and titrated using the di-n-butylamine method until the NCO content reaches (72±2)%. S2.2. The bismaleimide modifier WDDM521 curing agent and aromatic diamine DDS curing agent were reacted at 135℃ under nitrogen protection for 40 minutes. The reaction was monitored by infrared spectroscopy. When the characteristic double bond peak of maleimide near 2250cm-1 basically disappeared, the temperature was maintained for another 10 minutes. S2.3. Cool the rigid intermediate to 95°C, add the aromatic amine DMTDA curing agent and stir for 25 min. Then add the prepolymer obtained in step S1 and stir continuously at 300-500 rpm for (90±5) min. Cool to 50°C, add the modified filler and antioxidant, mix, and then heat to 85°C and stir for 20 min. S2.4. Next, cool the system to (40±2)℃, and slowly add MFA-50 and accelerator at 800-1000 rpm, stirring continuously for 15 minutes to ensure uniformity. Then, degas under a vacuum of -0.095MPa or higher for at least 20 minutes until the liquid surface is calm and free of bubbles to obtain the curing agent system; S3. Stir the resin system and the curing agent system evenly, add the reinforcing material while stirring, and stir evenly to obtain epoxy splicing adhesive.
[0022] By adopting the above technical solution, stepwise prepolymerization is transformed into a controllable main reaction for constructing the main network, avoiding the "amine-NCO" side reaction. At the molecular level, through prepolymer synthesis and rigid intermediate preparation, a chemically bonded rigid-tough interpenetrating network prototype is pre-constructed, fundamentally solving the brittleness problem of high-strength materials. In terms of curing kinetics, the preferential and rapid reaction between alicyclic amines and residual NCO is utilized to form an initial network, ensuring sufficient 45-70 minutes of construction time and enabling the material to establish early strength within 2-4 hours at room temperature, reaching ultra-high final strength after 24 hours. The final cured product will exhibit a compressive strength greater than 160 MPa, excellent impact resistance and fatigue resistance, and extremely strong adhesion to concrete and metal substrates. The epoxy splicing adhesive obtained in this application has a dense structure and excellent resistance to humid heat and chemical media, fully meeting the stringent requirements for high reliability and long service life of splicing materials in key engineering structures such as bridges and heavy buildings.
[0023] In summary, the present invention has the following beneficial effects: This application, based on multi-level collaborative design, systematically improves the comprehensive mechanical properties and construction adaptability of materials. At the molecular level, it employs epoxy resins with different functionalities and innovatively introduces isocyanate benzene ring structures into aromatic amine curing agents. The reaction of amine groups with NCO groups generates rigid urea bonds, fundamentally enhancing the rigidity and compressive strength of the crosslinked network. At the curing control level, by compounding alicyclic amines, staged curing at room temperature is achieved, ensuring sufficient working time and rapid early strength development. At the macroscopic structural level, it innovatively adopts a composite filler design of ultra-rigid fillers, porous rigid fillers, and steel fibers. The slurry, through its porous framework structure, forms a multi-interpenetrating network within the system, resulting in denser bonding. Furthermore, the crack-resistant and tensile-resistant properties of steel fibers create stronger cohesion within the colloid, further enhancing the toughness and mechanical properties of the cured material, thus preparing an ultra-high-strength epoxy bonding material that reacts at room temperature. Detailed Implementation
[0024] The present invention will be further described in detail below with reference to the embodiments. All reagents, unless otherwise specified, are commercially available conventional reagent products.
[0025] All raw materials used in this application are commercially available, specifically: The epoxy equivalent of bisphenol A type NPEL-128 epoxy resin is 185-186.6 g / eq, and the viscosity is 12000-15000 cps / 25℃. The epoxy equivalent of bisphenol F type NPEF-170 epoxy resin is 163-169 g / eq, and the viscosity is 2500-6000 cps / 25℃. The low-viscosity modified phenolic EPALLOY 8240 epoxy resin has an epoxy equivalent of 155-175 g / eq and a viscosity of 6000-8000 cps / 25℃. The epoxy equivalent of tetraglycidylamine modified EPM-420 epoxy resin is 110-125 g / eq, and the viscosity is 8000-12000 cps / 25℃. The bismaleimide modifier WDDM521 curing agent has an amine value of 185-225 mgKOH / g and a viscosity of 4500-12000 mPa·s (cP) at 40℃. The aromatic amine DMTDA curing agent has an amine value of 525-535 mgKOH / g and a viscosity of 500-800 mPa·s (cP) at 20℃. The cycloaliphatic amine MFA-50 curing agent has an amine value of 500-550 mgKOH / g and a viscosity of 200-600 mPa·s (cP) at 25℃. Aromatic diisocyanate MDI-100, NCO content >19%, viscosity at 25℃ 500mPa·s (cP). Aromatic diamine DDS curing agent has an amine value of 890-925 mgKOH / g and a viscosity of 20000-50000 mPa·s (cP) at 25℃. The multifunctional active diluent is pentaerythritol tetraglycidyl ether, model number Jiangsu Pulesi PETGE-95; The epoxy coupling agent is Evonik Dynasylan 1122; The toughening agent is a nanocomposite toughening agent, model number Shenzhen Materials Technology Co., Ltd. SC818; The defoamer is a polyether-modified silicone defoamer, model number Huisheng HS-025; The wetting and dispersing agent is BYK-2152; Nano-silica is a hydrophilic fumed silica, model number Cabot MS-60; The titanium dioxide is rutile titanium dioxide; The amino coupling agent is a bisamino (secondary amine) coupling agent, model number Dow Corning Z-6020; The antioxidant is a hindered phenol, model number BASF IRGAFOS 168; The accelerator is DMP-30.
[0026] In the embodiments of this application, the fillers in the resin system and the curing agent system are modified using the same method. The difference lies in the amount and type of filler used in each system. The specific modification methods are as follows: Preparation Example 1
[0027] Filler modification includes the following steps: S1. First, dry the compounded filler at 105℃ for 12 hours to remove moisture from the filler; S2. Ethanolamine and 1,4-butanediol are mixed and dissolved in propylene glycol methyl ether, wherein the mass ratio of ethanolamine:1,4-butanediol:propylene glycol methyl ether is 6:4:25. After stirring and mixing at 80±2℃, an activation solution is obtained. The activation solution is added dropwise to the packing material and mixed evenly with the packing material using a horizontal ribbon mixer. The reaction is carried out for 35-40 minutes to obtain activated packing material. The weight ratio of activation solution to compound packing material is 7:30. S3. The terminal amino polyether with a molar ratio of (NCO:-NH2=2.1:1) is reacted with isocyanate at 60±2℃ for 60-90 min to obtain a prepolymer, and the NCO content is monitored by di-n-butylamine titration to ensure it reaches the theoretical value. S4. After the prepolymer and activated filler are uniformly dispersed under high shear, the temperature is raised to 80±2℃ at a rate of 1-2℃ / min, and the reaction is continued at this temperature for 110±10 minutes to obtain the modified filler. Preparation Example 2
[0028] A method for preparing hyperbranched epoxy-polyurethane hybrids includes the following steps: Under dry nitrogen protection, polytetrahydrofuran ether diol and isophorone diisocyanate are reacted at 80±2℃ for 2-3 hours to obtain an NCO-terminated polyurethane prepolymer. The NCO content of the prepolymer should be controlled at 10%-15%. The prepolymer temperature is maintained at 70±5℃. Triethanolamine with a molar ratio of 0.68:1 to PTMG is added dropwise over 1.5 hours, while stirring at a constant speed of 200-300 rpm to form a stable emulsion. After the addition is complete, the reaction continues at 70±5℃ for 1.5 hours until the NCO content drops to near zero, indicating that the chain extension reaction is basically complete. The branched polyol intermediate obtained in the previous step is dissolved in 1.8 times (by mass) propylene glycol methyl ether acetate and transferred to a reactor equipped with a stirrer and thermometer. Sodium hydroxide aqueous solution is added, and the mixture is stirred thoroughly at 50-60℃ to form a stable two-phase system. Then, epichlorohydrin is slowly added dropwise while maintaining the pH value within the range of 8-10. The epoxidation reaction is carried out for 5-6 hours to generate a hyperbranched epoxy-polyurethane hybrid with epoxy groups at the ends. After the reaction is completed, the mixture must be washed four times with hot water at 70°C until the aqueous phase is neutral. The final wash water is then tested with silver nitrate solution until no chloride ion precipitate (white turbidity) is produced. The molar ratio of polytetrahydrofuran ether glycol (PTMG) to isophorone diisocyanate (IPDI) is 1:2.05, the amount of triethanolamine as a chain extender is 0.68:1 for the PTMG molar ratio, and the molar ratio of epichlorohydrin to PTMG is 8:1. Example 1
[0029] A room-temperature curing ultra-high strength epoxy splicing adhesive includes a resin system, a curing agent system, and reinforcing steel fiber. The resin system includes the following raw materials: 15 kg of composite epoxy resin, 3 kg of multifunctional reactive diluent, 1 kg of epoxy coupling agent, 3 kg of toughening agent, 1 kg of defoamer, 2 kg of wetting and dispersing agent, and 40 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined quartz sand, nano-silica, and titanium dioxide in a weight ratio of 2:2:0.1:0.1. The particle size of corundum is 800 mesh, and the particle size of calcined quartz sand is 60-120 mesh. The composite resins include 5 kg of bisphenol A type NPEL-128 epoxy resin, 10 kg of bisphenol F type NPEF-170 epoxy resin, 5 kg of low viscosity modified phenolic EPALLOY 8240 epoxy resin, 10 kg of tetraglycidylamine type modified EPM-420 epoxy resin, and 10 kg of the hyperbranched epoxy-polyurethane hybrid obtained in Preparation Example 2. The curing agent system includes the following raw materials: 15 kg of composite curing agent, 0.5 kg of amino-terminated polyether D-230, 1 kg of 1,4-butanediol, 0.1 kg of diethanolamine, 1 kg of antioxidant, 3 kg of accelerator, and 30 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined alumina powder, nano silica and carbon black in a weight ratio of 2:1:0.2:0.05. The particle size of corundum is 60-120 mesh, and the particle size of calcined alumina powder is 1000 mesh. The composite curing agent includes 5 kg of alicyclic amine MFA-50 curing agent, 1 kg of aromatic diisocyanate, 5 kg of aromatic diamine DDS curing agent, 1 kg of aromatic amine DMTDA curing agent, and 5 kg of bismaleimide modifier WDDM521 curing agent. Its preparation method includes the following steps: S1. Preparation of resin system: Mix the raw materials in the composite epoxy resin at 60°C, stir evenly, add toughening agent, modified filler and epoxy coupling agent, heat the system to 80°C, disperse at high speed for 30 min, cool to 50°C, add multifunctional active diluent and wetting and dispersing agent, stir at low speed for 20 min, add defoamer and vacuum degas to obtain multiphase resin system; S2. Preparation of curing agent system: Composite curing agents include alicyclic amine MFA-50 curing agent, aromatic diisocyanate, aromatic diamine DDS curing agent, aromatic amine DMTDA curing agent, and bismaleimide modifier WDDM521 curing agent. S2.1. Aromatic diisocyanate is reacted with amino-terminated polyether D-230, 1,4-butanediol and diethanolamine at 80°C for 2-3 hours, and samples are taken periodically and titrated using the di-n-butylamine method until the NCO content reaches (72±2)%. S2.2. The bismaleimide modifier WDDM521 curing agent and aromatic diamine DDS curing agent were reacted at 135℃ under nitrogen protection for 40 minutes. The reaction was monitored by infrared spectroscopy. When the characteristic double bond peak of maleimide near 2250cm-1 basically disappeared, the temperature was maintained for another 10 minutes. S2.3. Cool the rigid intermediate to 95°C, add the aromatic amine DMTDA curing agent and stir for 25 min. Then add the prepolymer obtained in step S2.1 and stir continuously at 300-500 rpm for (90±5) min. Cool to 50°C, add the modified filler and antioxidant, mix, and then heat to 85°C and stir for 20 min. S2.4. Next, cool the system to (40±2)℃, and slowly add MFA-50 and accelerator at 800-1000 rpm, stirring continuously for 15 minutes to ensure uniformity. Then, degas under a vacuum of -0.095MPa or higher for at least 20 minutes until the liquid surface is calm and free of bubbles to obtain the curing agent system; S3. Mix the resin system and the curing agent system at a weight ratio of 3:1 until homogeneous. Add steel fibers while mixing. After mixing until homogeneous, the epoxy splicing adhesive is obtained, wherein the weight ratio of the resin system to the steel fibers is 10:1. Example 2
[0030] A room-temperature curing ultra-high strength epoxy splicing adhesive includes a resin system, a curing agent system, and reinforcing steel fiber. The resin system includes the following raw materials: 18 kg of composite epoxy resin, 4 kg of multifunctional reactive diluent, 1 kg of epoxy coupling agent, 4 kg of toughening agent, 1 kg of defoamer, 3 kg of wetting and dispersing agent, and 60 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined quartz sand, nano silica, and titanium dioxide in a weight ratio of 3:3:0.2:0.1. The particle size of corundum is 800 mesh, and the particle size of calcined quartz sand is 60-120 mesh. The composite resins include 8 kg of bisphenol A type NPEL-128 epoxy resin, 5 kg of bisphenol F type NPEF-170 epoxy resin, 7 kg of low viscosity modified phenolic EPALLOY 8240 epoxy resin, 10 kg of tetraglycidylamine type modified EPM-420 epoxy resin, and 12 kg of the hyperbranched epoxy-polyurethane hybrid obtained in Preparation Example 2. The curing agent system includes the following raw materials: 25 kg of composite curing agent, 1 kg of amino-terminated polyether D-230, 1.2 kg of 1,4-butanediol, 0.3 kg of diethanolamine, 1 kg of antioxidant, 4 kg of accelerator, and 60 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined alumina powder, nano silica and carbon black in a weight ratio of 4:2:0.2:0.1. The particle size of corundum is 60-120 mesh and the particle size of calcined alumina powder is 1000 mesh. The composite curing agent includes 7 kg of alicyclic amine MFA-50 curing agent, 4 kg of aromatic diisocyanate, 10 kg of aromatic diamine DDS curing agent, 3 kg of aromatic amine DMTDA curing agent, and 10 kg of bismaleimide modifier WDDM521 curing agent. The preparation steps are the same as in Example 1. Example 3
[0031] A room-temperature curing ultra-high strength epoxy splicing adhesive includes a resin system, a curing agent system, and reinforcing steel fiber. The resin system includes the following raw materials: 20 kg of composite epoxy resin, 5 kg of multifunctional reactive diluent, 2 kg of epoxy coupling agent, 5 kg of toughening agent, 2 kg of defoamer, 5 kg of wetting and dispersing agent, and 80 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined quartz sand, nano silica, and titanium dioxide in a weight ratio of 4:5:0.5:0.1. The particle size of corundum is 800 mesh, and the particle size of calcined quartz sand is 120 mesh. The composite resins include 10 kg of bisphenol A type NPEL-128 epoxy resin, 5 kg of bisphenol F type NPEF-170 epoxy resin, 10 kg of low viscosity modified phenolic EPALLOY 8240 epoxy resin, 5 kg of tetraglycidylamine type modified EPM-420 epoxy resin, and 15 kg of the hyperbranched epoxy-polyurethane hybrid obtained in Preparation Example 2. The curing agent system includes the following raw materials: 30 kg of composite curing agent, 2 kg of amino-terminated polyether D-230, 1.5 kg of 1,4-butanediol, 0.5 kg of diethanolamine, 2 kg of antioxidant, 5 kg of accelerator, and 83 kg of modified filler obtained by the modification method of Preparation Example 1. The modified filler includes corundum, calcined alumina powder, nano silica and carbon black in a weight ratio of 6:1:0.2:0.1. The particle size of corundum is 120 mesh and the particle size of calcined alumina powder is 1000 mesh. The composite curing agent includes 10 kg of alicyclic amine MFA-50 curing agent, 5 kg of aromatic diisocyanate, 8 kg of aromatic diamine DDS curing agent, 5 kg of aromatic amine DMTDA curing agent, and 10 kg of bismaleimide modifier WDDM521 curing agent. The preparation method and steps are the same as in Example 1. Example 4
[0032] A room-temperature curing ultra-high strength epoxy bonding adhesive differs from Example 2 in that: The weight ratio of the resin system to the curing agent system was 3.2:1, and the weight ratio of the resin system to the steel fiber was 5:1. All other aspects were the same as in Example 2. Example 5
[0033] A room-temperature curing ultra-high strength epoxy splicing adhesive differs from Example 2 in that the fillers used in both the resin system and the curing agent system are unmodified composite fillers, while all other aspects are the same as in Example 2. Example 6
[0034] A room-temperature curing ultra-high strength epoxy splicing adhesive differs from Example 2 in that: the resin system and the curing agent system are directly mixed at room temperature in a weight ratio of 2.8:1, and steel fibers are added and mixed evenly while stirring. Everything else is the same as in Example 2. Comparative Example 1
[0035] An epoxy bonding adhesive differs from Example 2 in that it uses an equal amount of commercially available cycloaliphatic amine system MFA-50 curing agent instead of a composite curing agent; otherwise, it is the same as Example 2. Comparative Example 2
[0036] An epoxy bonding adhesive differs from Example 2 in that the total amount of curing agent remains unchanged, and the composite curing agent is composed of alicyclic amine MFA-50 curing agent and aromatic amine DMTDA curing agent in a weight ratio of 2:1. All other aspects are the same as in Example 2. Comparative Example 3
[0037] An epoxy bonding adhesive differs from Example 2 in that the total amount of curing agent remains unchanged, and the composite curing agent is composed of alicyclic amine MFA-50 curing agent and bismaleimide modifier WDDM521 curing agent in a weight ratio of 1:1. All other aspects are the same as in Example 2. Comparative Example 4
[0038] An epoxy bonding adhesive differs from Example 2 in that the total amount of curing agent remains unchanged. The composite curing agent consists of 7 kg of alicyclic amine MFA-50 curing agent, 10 kg of aromatic diamine DDS curing agent, 3 kg of aromatic amine DMTDA curing agent, and 10 kg of bismaleimide modifier WDDM521 curing agent. All other components are the same as in Example 2. Comparative Example 5
[0039] An epoxy bonding adhesive differs from Example 2 in that an equal amount of bisphenol A type NPEL-128 epoxy resin is used instead of the composite epoxy resin, while all other aspects are the same as in Example 2. Comparative Example 6
[0040] An epoxy bonding adhesive differs from Example 2 in that the total amount of composite epoxy resin remains unchanged. The composite epoxy resin is composed of bisphenol A type NPEL-128 epoxy resin and tetraglycidylamine type modified EPM-420 epoxy resin in a weight ratio of 1:1. All other aspects are the same as in Example 2. Comparative Example 7
[0041] An epoxy bonding adhesive differs from Example 2 in that the total amount of composite epoxy resin remains unchanged. The composite epoxy resin is composed of bisphenol F type NPEF-170 epoxy resin and low viscosity modified phenolic EPALLOY 8240 epoxy resin in a weight ratio of 1:1. All other aspects are the same as in Example 2. Comparative Example 8
[0042] An epoxy splicing adhesive differs from Example 2 in that it does not contain reinforcing steel fibers, but is otherwise identical to Example 2. Performance testing
[0043] The epoxy bonding adhesives obtained in the above embodiments and comparative examples were subjected to performance testing. The testing of various properties was conducted according to the relevant provisions of TCECS 10080-2020 "Epoxy Adhesives for Precast Assembly". The resistance to humid heat aging was tested by placing the specimens in a humid heat environment at 50℃ and 95±3% relative humidity after 7 days of curing, followed by 90 days of curing. The specimens were then removed, cooled to 23±2℃, and the concrete-to-concrete flexural bonding performance was tested at this temperature. Three specimens were tested in each group. Failure occurring within the concrete was considered acceptable. Therefore, the performance requirement is that the concrete body fails, but the adhesive remains intact. The test results are shown in Table 1.
[0044] Table 1. Performance Test Results of Epoxy Joint Adhesive
[0045] Continued from Table 1
[0046] Referring to Table 1: The epoxy bonding adhesives obtained in Examples 1-6 of this application have good compressive strength. After the damp heat aging test, the failure only occurred in the concrete body, while the adhesive part remained intact without damage. This indicates that the combined use of the resin and curing agent in this application effectively improves the mechanical properties of the epoxy bonding adhesive. At the same time, by adjusting the proportion of components in each embodiment, flexible control of the application time and bonding time can be achieved to meet the needs of different construction scenarios.
[0047] Compared to Example 2, when only a single alicyclic amine MFA-50 curing agent was used, the early strength development of the resulting adhesive was faster, but the final compressive strength and heat distortion temperature were significantly reduced. The colloid deteriorated after humid heat aging. The fundamental reason for this was that the crosslinking network structure formed by the single curing agent was simple and insufficient in density, and lacked the rigid heat-resistant skeleton constructed by aromatic amines (DDS) and bismaleimide (WDDM521), which led to severe plasticization and strength degradation of the material under humid heat conditions.
[0048] Compared with Example 2, Comparative Examples 2-4 progressively revealed the key roles of each component in the composite curing agent. When only two (MFA-50 / DMTDA) or three (MFA-50 / WDDM521) curing agents were used, the colloid's resistance to humid heat aging, heat distortion temperature, and final strength all decreased, indicating a lack of support from high-strength, high-heat-resistant components and a deficiency in network performance. Even when four curing agents were used but the isocyanate component was missing (Comparative Example 4), the colloid failed to form an in-situ toughened polyurethane interpenetrating network, resulting in significantly inferior toughness and crack resistance compared to Example 2, further confirming the indispensability of isocyanate in achieving a "rigid-toughness balance." This also further illustrates that the synergistic use of curing agents in this application not only improves the epoxy bonding agent's resistance to humid heat aging but also helps to improve compressive strength.
[0049] Comparative Examples 5-7, compared with Example 2, demonstrate the necessity of the composite resin system design. When only a single bisphenol A epoxy resin (Comparative Example 5) is used, the lack of high-functionality resin and low crosslinking density lead to a significant overall decrease in compressive strength, modulus, and heat resistance, with severe performance degradation after hygrothermal aging. When only two types of resins are simply blended (Comparative Examples 6 and 7), although a certain individual property (such as the heat resistance of Comparative Example 6) may be improved, the lack of synergy from multi-functional resins and compatibilizing effect from hyperbranched hybrids results in an unbalanced overall performance, and its comprehensive mechanical properties and durability are still significantly lower than those of Example 2.
[0050] Compared to Example 2, Comparative Example 8 showed a significant decrease in tensile strength, crack resistance, and toughness of the colloid when steel fiber reinforcement was absent, exhibiting brittle failure under overload without the warning stage of fiber bridging. This directly demonstrates that steel fibers, as macroscopic reinforcements, form a multi-scale synergy with the resin-curing agent micronetwork, which is key to obtaining ultra-high strength and high crack resistance.
[0051] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A room-temperature curing ultra-high strength epoxy bonding adhesive, comprising a resin system, a curing agent system, and a reinforcing material, characterized in that: The weight ratio of the resin system to the curing agent system is (2.8-3.2):1, and the weight ratio of the resin system to the reinforcing material is (10-5):
1. The resin system comprises the following raw materials in parts by weight: 15-20 parts of composite epoxy resin, 3-5 parts of multifunctional reactive diluent, 1-2 parts of epoxy coupling agent, 3-5 parts of toughening agent, 1-2 parts of defoamer, 2-5 parts of wetting and dispersing agent, and 40-80 parts of filler. The curing agent system comprises the following raw materials in parts by weight: 15-30 parts of composite curing agent, 0.5-2 parts of amino-terminated polyether D-230, 1-1.5 parts of 1,4-butanediol, 0.1-0.5 parts of diethanolamine, 1-2 parts of antioxidant, 3-5 parts of accelerator, and 30-83 parts of filler.
2. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 1, characterized in that: The composite epoxy resin comprises the following raw materials in parts by weight: 5-10 parts of bisphenol A type NPEL-128 epoxy resin, 5-10 parts of bisphenol F type NPEF-170 epoxy resin, 5-10 parts of low viscosity modified phenolic EPALLOY 8240 epoxy resin, 5-10 parts of tetraglycidylamine type modified EPM-420 epoxy resin, and 10-15 parts of hyperbranched epoxy-polyurethane hybrid.
3. The room-temperature curing ultra-high strength epoxy bonding adhesive according to claim 1, characterized in that: The hyperbranched epoxy-polyurethane hybrid is obtained by the following preparation method: NCO-terminated polyurethane prepolymer and chain extender are reacted and then epichlorohydrin is added. After epoxidation under alkaline conditions, the hyperbranched epoxy-polyurethane hybrid is obtained.
4. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 1, characterized in that: The composite curing agent comprises the following raw materials in parts by weight: 5-10 parts of alicyclic amine MFA-50 curing agent, 1-5 parts of aromatic diisocyanate, 5-10 parts of aromatic diamine DDS curing agent, 1-5 parts of aromatic amine DMTDA curing agent, and 5-10 parts of bismaleimide modifier WDDM521 curing agent.
5. The room-temperature curing ultra-high strength epoxy bonding adhesive according to claim 1, characterized in that: The fillers in both the resin system and the curing agent system were obtained using the following modification method: S1. First, dry the compounded filler at 105℃ for 12 hours to remove moisture from the filler; S2. Ethanolamine and 1,4-butanediol are mixed and dissolved in propylene glycol methyl ether, wherein the mass ratio of ethanolamine:1,4-butanediol:propylene glycol methyl ether is 6:4:
25. After stirring and mixing at 80±2℃, an activation solution is obtained. The activation solution is added dropwise to the packing material and mixed evenly with the packing material using a horizontal ribbon mixer. The reaction is carried out for 35-40 minutes to obtain activated packing material. The weight ratio of activation solution to compound packing material is 7:
30. S3. According to the molar ratio of NCO:-NH2 of 2.1:1, the terminal amino polyether and isocyanate were reacted at 60±2℃ for 60-90 min to obtain the prepolymer, and the NCO content was monitored by di-n-butylamine titration to ensure it reached the theoretical value. S4. After mixing the prepolymer and activated filler, disperse them evenly under high shear, and then heat them to 80±2℃ at a rate of 1-2℃ / min. Continue the reaction at this temperature for 110±10 minutes to obtain the modified filler.
6. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 1, characterized in that: The fillers in the resin system include corundum, calcined quartz sand, nano-silica and titanium dioxide in a weight ratio of (2-4):(2-5):(0-0.5):(0-0.1).
7. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 6, characterized in that: The particle size of the corundum is 800 mesh, and the particle size of the calcined quartz sand is 60-120 mesh.
8. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 1, characterized in that: The fillers in the curing agent system include corundum, calcined alumina powder, nano-silica and carbon black in a weight ratio of (2-6):(1-2):(0-0.2):(0-0.1).
9. The room-temperature curing ultra-high strength epoxy splicing adhesive according to claim 8, characterized in that: The particle size of the corundum is 60-120 mesh, and the particle size of the calcined alumina powder is 1000 mesh.
10. A method for preparing a room-temperature curing ultra-high strength epoxy bonding adhesive as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Preparation of resin system: Mix the raw materials in the composite epoxy resin at 60°C, stir evenly, add multifunctional active diluent, toughening agent, filler and epoxy coupling agent, heat the system to 80°C, disperse at high speed for 30 min, cool to 50°C, add defoamer and wetting and dispersing agent, stir at low speed for 20 min, and degas under vacuum for 30 min to obtain multiphase resin system; S2. Preparation of curing agent system: Composite curing agents include alicyclic amine MFA-50 curing agent, aromatic diisocyanate, aromatic diamine DDS curing agent, aromatic amine DMTDA curing agent, and bismaleimide modifier WDDM521 curing agent. S2.
1. Aromatic diisocyanate is reacted with amino-terminated polyether D-230, 1,4-butanediol and diethanolamine at 80°C for 2-3 hours, and samples are taken periodically and titrated using the di-n-butylamine method until the NCO content reaches (72±2)%. S2.
2. The bismaleimide modifier WDDM521 curing agent and aromatic diamine DDS curing agent were reacted at 135℃ under nitrogen protection for 40 minutes. The reaction was monitored by infrared spectroscopy. When the characteristic double bond peak of maleimide near 2250cm-1 basically disappeared, the temperature was maintained for another 10 minutes. S2.
3. Cool the rigid intermediate to 95°C, add the aromatic amine DMTDA curing agent and stir for 25 min. Then add the prepolymer obtained in step S1 and stir continuously at 300-500 rpm for (90±5) min. Cool to 50°C, add the modified filler and antioxidant, mix, and then heat to 85°C and stir for 20 min. S2.
4. Next, cool the system to (40±2)℃, and slowly add MFA-50 and accelerator at 800-1000 rpm, stirring continuously for 15 minutes to ensure uniformity. Then, degas under a vacuum of -0.095MPa or higher for at least 20 minutes until the liquid surface is calm and free of bubbles to obtain the curing agent system; S3. Stir the resin system and the curing agent system evenly, add the reinforcing material while stirring, and stir evenly to obtain epoxy splicing adhesive.