High-strength long-life epoxy splicing material and preparation method thereof

Abstract

According to the high-strength long-service-life epoxy splicing material and the preparation method thereof provided by the invention, an epoxy resin material with high toughness, high strength and long service life is obtained through hybrid fiber hydro-thermal synthesis grafting, micro-carrier curing agent construction and vacuum compounding processes. Wherein the bisphenol A epoxy resin is a matrix; the zinc oxide whiskers are subjected to surface modification to form hybrid fibers as a reinforcing phase; polyethylene glycol low-temperature trigger microspheres and polyurethane / epoxy double-wall microcapsules are used as high-temperature curing agents; the stress response microsphere of the composite wall material epoxy siloxane is a self-repairing component; the synthesized multifunctional curing accelerator X has curing acceleration and ultraviolet absorption shielding effects. The epoxy splicing material obtained by the invention is quick to cure, has high strength, self-repairing function and long-term weather resistance, is suitable for harsh environments such as building expansion joints and building component splicing, and has rich application prospects.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a high-strength, long-life epoxy splicing material and its preparation method. Background Technology

[0002] Epoxy resin splicing materials are widely used in the field of building construction detailing, such as splicing concrete components, steel structure reinforcement and bonding, and splicing of waterproof materials (such as EPDM rubber, polyvinyl chloride, elastomer modified bitumen, plastomeric modified bitumen, self-adhesive rubber bitumen, thermoplastic polyolefin waterproof membrane, fiberglass asphalt shingles, and sodium bentonite waterproof blanket).

[0003] Epoxy resin is a type of thermosetting polymer obtained by the condensation polymerization of bisphenol A / bisphenol F and epichlorohydrin. Its molecular chain is rich in epoxy groups (—CH—). —O—), which can undergo ring-opening crosslinking with curing agents such as amines, acid anhydrides, and phenolic resins to form a three-dimensional dense network. This system has excellent mechanical strength (tensile strength 20–80 MPa), chemical resistance, low shrinkage (<3%), and electrical insulation. It exhibits high adhesion on polar substrates such as metals, concrete, ceramics, and glass, and has been widely used in building structure reinforcement, prefabricated building splicing, bridge expansion joints, and wet joints of precast components.

[0004] However, pure epoxy cured products have high crosslinking density and high internal stress, resulting in high brittleness, poor toughness, insufficient impact resistance and fatigue performance. They are prone to microcracks during long-term service, leading to failure of the bonding interface. At the same time, the ether bonds and hydroxyl groups in epoxy molecules are prone to degradation under humid heat, ultraviolet light or freeze-thaw cycles, resulting in yellowing, chalking and strength reduction, making it difficult to meet the durability requirements of "century-old buildings".

[0005] In recent years, performance optimization of epoxy resin adhesives has become a research hotspot. Although existing technologies have made some progress, significant limitations still exist. For example, patent document CN119119932A discloses a high-strength, high-toughness, high-temperature resistant epoxy resin adhesive, its preparation method, and its application. In this invention, the adhesive contains epoxy resin, curing agent, organic solvent, curing accelerator (2-methoxy-6-methylaminopyridine-boron trifluoride complex), and inorganic filler. The curing accelerator can avoid pre-curing and lower the curing temperature, improving mechanical properties and high-temperature resistance. However, the preparation steps of this curing accelerator are cumbersome, costly, and do not solve the weather resistance problem.

[0006] Patent document CN108611037A discloses an epoxy resin adhesive with improved elasticity and toughness. In this invention, the epoxy resin adhesive is composed of component A (containing polyurethane-modified epoxy resin, bisphenol F epoxy resin, etc.) and component B (containing curing agent, organobentonite, etc.), mixed at a mass ratio of 3-4:1. By adding polypropylene fibers and specially prepared elastomer microparticles, the toughness and elasticity of the adhesive are improved, enhancing its impact resistance and crack resistance. However, it has poor weather resistance, exhibits performance degradation at higher temperatures, and lacks self-healing capabilities.

[0007] As the requirements for bonding materials in fields such as construction and aerospace evolve towards "high strength, high toughness, wide temperature range adaptability, and long lifespan," existing materials can no longer meet the demands of complex scenarios. For example, large-scale building splicing requires materials to maintain stable bonding strength within a temperature range of -30℃ to 80℃, while also demanding a curing time of ≤12h and a shrinkage rate of ≤3%. Meanwhile, next-generation electronic device encapsulation requires materials that combine resistance to damp heat (95% RH) and weather resistance (no significant performance degradation after 3000h of UV aging). Therefore, developing a novel epoxy resin bonding material with balanced comprehensive performance, rapid curing, and adaptability to multiple scenarios, possessing both high strength and long lifespan, has become crucial for overcoming existing technological bottlenecks and driving industry development. Summary of the Invention

[0008] To achieve the objectives of this invention, a high-strength, long-life epoxy splicing material and its preparation method are provided, with a controllable process. The material achieves a balance of high toughness, high strength, and long lifespan through the synergistic effect of hybrid fiber reinforcement, a dual-trigger curing system, and self-healing components. It possesses excellent mechanical properties, high strength, high modulus, good interfacial bonding, low porosity, and good weather resistance, enabling long-term service in extreme environments. The invented curing accelerator X significantly shortens the manufacturing time and has multiple functions including UV absorption and shielding.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-strength, long-life epoxy splicing material comprises the following components by weight: resin matrix, 100 parts of bisphenol A epoxy resin (E-51); reinforcing phase, 15-20 parts of zinc oxide whisker-based hybrid fibers; filler, 25-30 parts of flake silica powder (diameter-to-thickness ratio 10:1); low-temperature curing trigger, 5-8 parts of 2-ethyl-4-methylimidazolium / PEG600 microspheres; high-temperature curing trigger, 8-12 parts of phenolic amine-hydrazide / polyurethane-epoxy double-walled microcapsules; curing accelerator X, 0.5-1 part; and self-healing component, 3-5 parts of terminal epoxy siloxane / gelatin-gum arabic microspheres.

[0010] The preparation steps of the high-strength, long-life epoxy splicing material are as follows: Bisphenol A epoxy resin E-51 (100 parts) is initially mixed with hybrid fibers (15-20 parts) and sheet-like silica powder (diameter-to-thickness ratio 10:1, 25-30 parts) at 40-50℃ for 0.5 hours. Low-temperature curing microspheres (5-8 parts) and high-temperature curing microcapsules (8-12 parts) are added in sequence. Then, curing accelerator X (0.5-1 parts) and self-healing microspheres (3-5 parts) are added. Finally, the product is obtained by degassing for 10 minutes at a vacuum degree of -0.095 MPa and a rotation speed of 200-300 r / min.

[0011] The preparation method of the zinc oxide whisker-based hybrid fiber reinforcement phase is as follows: 5-7 parts of zinc acetate, 3-5 parts of urea and 100 parts of deionized water are mixed and hydrothermally reacted at 180-200℃ for 12-15 hours to obtain zinc oxide whiskers with an aspect ratio of 15-25:1; the whiskers are immersed in a 2-5wt% ethanol solution of silane coupling agent KH-550 for 1 hour, filtered and dried; 10 parts of modified whiskers, 8-12 parts of vinyl ferrocene, 40-60 parts of hydrogen-containing silicone oil (hydrogen content 0.8-1.2%) and 0.1-0.3 parts of isopropyl titanate are added to a reaction vessel and stirred at 80-85℃ for 2-3 hours, and then processed by a high-speed homogenizer to obtain hybrid fibers with a length of 200±50μm.

[0012] Preferably, the zinc acetate is 1.5-1 times the amount of urea. Preferably, the hydrogen-containing silicone oil is methyl hydrogen-containing MQ silicone resin, and the amount of isopropyl titanate added is 1-3% of the mass of vinyl ferrocene; Preferably, the high-speed homogenizer operates at a rotation speed of 12,000-15,000 r / min and a processing time of 5-8 minutes.

[0013] The preparation method of the low-temperature curing microspheres is as follows: 3-5 parts of 2-ethyl-4-methylimidazolium are mixed with 10-15 parts of molten polyethylene glycol PEG600, and dispersed and emulsified at high speed of 1000 r / min under heating conditions. After cooling, microspheres with a particle size of 5-10 μm are obtained. Preferably, the heating condition is 50-60°C; The preparation method of the high-temperature curing microcapsules is as follows: 4-6 parts of phenolic amine T31 and 2-4 parts of sebacic dihydrazide are dissolved in ethyl acetate as core material; 3 parts of bisphenol A epoxy resin E-51 and 2 parts of diisocyanate HDI are prepolymerized at 60°C for 30 minutes to obtain a polyurethane-epoxy hybrid wall material solution; by high-speed stirring, the core material solution is dropped into the wall material solution, and double-walled microcapsules with a wall thickness of 0.5-1 μm are formed by interfacial polymerization.

[0014] Preferably, the NCO / OH molar ratio in the polyurethane-epoxy hybrid wall material is (1-1.2):1; Preferably, the stirring rate of the high-speed stirring is 8000-10000 r / min.

[0015] The self-healing component is prepared as follows: 5 parts of terminal epoxy siloxane (epoxide value 0.45-0.55) are mixed with 10 parts of ethyl acetate to obtain an oil phase; 4 parts of gelatin and 3 parts of gum arabic are dissolved in 100 parts of deionized water to obtain an aqueous phase; the oil phase is dropped into the aqueous phase at 50℃, the pH is adjusted to allow for re-coagulation, the temperature is lowered to 5℃ and cured for 2 hours, and after filtration and drying, self-healing microspheres with a particle size of 20-50μm are obtained.

[0016] Preferably, the mass ratio of gelatin to gum arabic is (1-1.3):1; Preferably, the pH adjustment range is 4.0-4.5.

[0017] The preparation method of the curing accelerator X is as follows: 1) 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. After the reaction, the byproduct ethanol was removed by vacuum distillation.

[0018] 2) Dissolve 1 part of the product from the previous step in THF, and add 1-2 parts of boron trifluoromethanesulfonate dropwise at 0°C. Then, raise the temperature to room temperature and stir for 24 hours. After concentration, the reaction solution is purified by recrystallization with an organic solvent to obtain colorless crystals of the target compound.

[0019] Preferably, the organic solvent is selected from any one of acetonitrile, n-hexane, acetone, and n-heptane.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention uses bisphenol A epoxy resin as the matrix, combined with a zinc oxide whisker-based hybrid fiber reinforcement phase. The hybrid fibers are prepared by reacting surface-modified zinc oxide whiskers with vinyl ferrocene and hydrogen-containing silicone oil. Through the synergy of rigid whiskers and organic segments, the tensile strength and toughness of the material are significantly improved, solving the problem of high brittleness in pure epoxy. Flake-shaped silica powder, as a filler, reduces curing shrinkage and enhances dimensional stability. A dual-trigger curing system is constructed using low-temperature curing-triggered microspheres and high-temperature curing microcapsules. The low-temperature microspheres achieve rapid initial curing, while the high-temperature microcapsules ensure complete curing, balancing curing efficiency and low internal stress, adapting to a wide temperature range of -30℃ to 80℃. The addition of curing accelerator X further shortens the curing time and improves construction efficiency. The self-healing component can respond and repair microcracks in the material, significantly extending its service life in conjunction with the material's weather-resistant design, meeting the durability requirements of buildings. In summary, this material combines high strength, high toughness, rapid curing, self-healing properties, and long-term weather resistance, making it suitable for harsh environments such as building expansion joints and component splicing, and has broad application prospects. Detailed Implementation

[0021] The following examples are used to further explain and illustrate the present invention; however, they do not constitute a limitation or restriction on the scope of the present invention.

[0022] Example 1: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 15 parts of zinc oxide whisker-based hybrid fiber, 25 parts of flake silica powder (diameter-to-thickness ratio 10:1), 5 parts of low-temperature curing microspheres, 8 parts of high-temperature curing microcapsules, 0.5 parts of curing accelerator, and 3 parts of self-healing microspheres. S2: Preparation of zinc oxide whiskers: Mix 5 parts zinc acetate, 3 parts urea and 100 parts deionized water, and react hydrothermally at 180℃ for 12 hours to obtain zinc oxide whiskers with an aspect ratio of 15:1. S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 2wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 8 parts of vinyl ferrocene, 40 parts of hydrogen-containing silicone oil (hydrogen content 0.8%) and 0.1 parts of isopropyl titanate (1% of the mass of vinyl ferrocene) at 80℃ for 2 hours. After being processed by a high-speed homogenizer (12000r / min) for 5 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 3 parts of 2-ethyl-4-methylimidazolium and 10 parts of molten PEG600 were dispersed and emulsified at 1000 r / min at 50℃, and microspheres with a particle size of 5-10 μm were obtained after cooling. S5: Preparation of high-temperature curing microcapsules: 14 parts of phenolic amine T3 and 2 parts of sebacic dihydrazide were dissolved in ethyl acetate as core material. 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1:1) to obtain wall material. The core material was dripped into the wall material at 8000 r / min, and microcapsules with a wall thickness of 0.5 μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.45) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 4 parts of gum arabic (mass ratio 1:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.0, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 1 part of boron trifluoromethanesulfonate and then recrystallized with n-hexane. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 40°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 200r / min to obtain the finished product.

[0023] Example 2: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 17 parts of zinc oxide whisker-based hybrid fiber, 27 parts of flake silica powder (diameter-to-thickness ratio 10:1), 6 parts of low-temperature curing microspheres, 10 parts of high-temperature curing microcapsules, 0.7 parts of curing accelerator, and 4 parts of self-healing microspheres. S2: Preparation of zinc oxide whiskers: Mix 6 parts zinc acetate, 4 parts urea and 100 parts deionized water, and react hydrothermally at 190℃ for 13 hours to obtain zinc oxide whiskers with an aspect ratio of 20:1. S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 3wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 10 parts of vinyl ferrocene, 50 parts of hydrogen-containing silicone oil (hydrogen content 1.0%) and 0.2 parts of isopropyl titanate (2% of the mass of vinyl ferrocene) at 82℃ for 2.5 hours. After being processed by a high-speed homogenizer (13500r / min) for 6 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 4 parts of 2-ethyl-4-methylimidazolium and 12 parts of molten PEG600 were dispersed and emulsified at 55℃ and 1000 r / min. After cooling, microspheres with a particle size of 5-10 μm were obtained. S5: Preparation of high-temperature curing microcapsules: 15 parts of phenolic amine T3 and 3 parts of sebacic dihydrazide were dissolved in ethyl acetate as core material. 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1.1:1) to obtain wall material. The core material was dripped into the wall material at 9000 r / min, and microcapsules with a wall thickness of 0.8 μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.50) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 3.3 parts of gum arabic (mass ratio 1.2:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.2, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 1.5 parts of boron trifluoromethanesulfonate and then recrystallized with acetonitrile. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 45°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 250r / min to obtain the finished product.

[0024] Example 3: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 20 parts of zinc oxide whisker-based hybrid fiber, 30 parts of flake silica powder (diameter-to-thickness ratio 10:1), 8 parts of low-temperature curing microspheres, 12 parts of high-temperature curing microcapsules, 1 part of curing accelerator, and 5 parts of self-healing microspheres. S2: Preparation of zinc oxide whiskers: Mix 7 parts zinc acetate, 5 parts urea and 100 parts deionized water, and react hydrothermally at 200℃ for 15 hours to obtain zinc oxide whiskers with an aspect ratio of 25:1. S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 5wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 12 parts of vinyl ferrocene, 60 parts of hydrogen-containing silicone oil (hydrogen content 1.2%) and 0.3 parts of isopropyl titanate (3% of the mass of vinyl ferrocene) at 85℃ for 3 hours. After being processed by a high-speed homogenizer (15000r / min) for 8 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 5 parts of 2-ethyl-4-methylimidazolium and 15 parts of molten PEG600 were dispersed and emulsified at 1000 r / min at 60℃, and microspheres with a particle size of 5-10 μm were obtained after cooling. S5: Preparation of high-temperature curing microcapsules: 16 parts of phenolic amine T3 and 4 parts of sebacic dihydrazide were dissolved in ethyl acetate as core material. 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1.2:1) to obtain wall material. The core material was dripped into the wall material at 10000r / min, and microcapsules with a wall thickness of 1μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.55) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 3.1 parts of gum arabic (mass ratio 1.3:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.5, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50 μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 2 parts of boron trifluoromethanesulfonate and then recrystallized with acetone. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 50°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 300r / min to obtain the finished product.

[0025] Example 4: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 16 parts of zinc oxide whisker-based hybrid fiber, 26 parts of flake silica powder (diameter-to-thickness ratio 10:1), 7 parts of low-temperature curing microspheres, 9 parts of high-temperature curing microcapsules, 0.6 parts of curing accelerator, and 3.5 parts of self-healing microspheres. S2: Preparation of zinc oxide whiskers: 5.5 parts of zinc acetate, 3.5 parts of urea and 100 parts of deionized water were mixed and hydrothermally reacted at 185℃ for 13 hours to obtain zinc oxide whiskers with an aspect ratio of 18:1. S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 3wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 9 parts of vinyl ferrocene, 45 parts of hydrogen-containing silicone oil (hydrogen content 0.9%) and 0.15 parts of isopropyl titanate (1.5% of the mass of vinyl ferrocene) at 81℃ for 2.2 hours. After being processed by a high-speed homogenizer (12500r / min) for 5.5 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 3.5 parts of 2-ethyl-4-methylimidazolium and 11 parts of molten PEG600 were dispersed and emulsified at 52℃ and 1000 r / min. After cooling, microspheres with a particle size of 5-10 μm were obtained. S5: Preparation of high-temperature curing microcapsules: 14.5 parts of phenolic amine T3 and 2.5 parts of sebacic dihydrazide were dissolved in ethyl acetate as core material. 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1.05:1) to obtain wall material. The core material was dripped into the wall material at 8500 r / min, and microcapsules with a wall thickness of 0.6 μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.48) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 3.5 parts of gum arabic (mass ratio 1.1:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.1, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50 μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 1.2 parts of boron trifluoromethanesulfonate and then recrystallized with n-heptane. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 42°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 220r / min to obtain the finished product.

[0026] Example 5: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 19 parts of zinc oxide whisker-based hybrid fiber, 29 parts of flake silica powder (diameter-to-thickness ratio 10:1), 6.5 parts of low-temperature curing microspheres, 11 parts of high-temperature curing microcapsules, 0.9 parts of curing accelerator X, and 4.5 parts of self-healing microspheres. S2: Preparation of zinc oxide whiskers: 6.5 parts of zinc acetate, 4.5 parts of urea and 100 parts of deionized water were mixed and hydrothermally reacted at 195℃ for 14 hours to obtain zinc oxide whiskers with an aspect ratio of 23:1. S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 4wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 11 parts of vinyl ferrocene, 55 parts of hydrogen-containing silicone oil (hydrogen content 1.1%) and 0.25 parts of isopropyl titanate (2.5% of the mass of vinyl ferrocene) at 84℃ for 2.8 hours. After being processed by a high-speed homogenizer (14000r / min) for 7 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 4.5 parts of 2-ethyl-4-methylimidazolium and 14 parts of molten PEG600 were dispersed and emulsified at 58℃ and 1000 r / min. After cooling, microspheres with a particle size of 5-10 μm were obtained. S5: Preparation of high-temperature curing microcapsules: 15.5 parts of phenolic amine T3 and 3.5 parts of sebacic dihydrazide were dissolved in ethyl acetate as core material. 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1.15:1) to obtain wall material. The core material was dripped into the wall material at 9500 r / min, and microcapsules with a wall thickness of 0.9 μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.52) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 3.2 parts of gum arabic (mass ratio 1.25:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.4, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50 μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 1.8 parts of boron trifluoromethanesulfonate and then recrystallized with acetonitrile. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 48°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 280r / min to obtain the finished product.

[0027] Example 6: A high-strength, long-life epoxy splicing material and its preparation method, comprising the following steps: S1: Prepare raw materials by weight: 100 parts of bisphenol A epoxy resin (E-51), 18 parts of zinc oxide whisker-based hybrid fiber, 28 parts of flake silica powder (diameter-to-thickness ratio 10:1), 6 parts of low-temperature curing microspheres, 10 parts of high-temperature curing microcapsules, 0.8 parts of curing accelerator, and 4 parts of self-healing microspheres; S2: Preparation of zinc oxide whiskers: Mix 6 parts zinc acetate, 4 parts urea and 100 parts deionized water, and react hydrothermally at 190℃ for 14 hours to obtain zinc oxide whiskers with an aspect ratio of 20:1; S3: Preparation of hybrid fibers: Zinc oxide whiskers were treated with a 4wt% ethanol solution of silane coupling agent KH-550 for 1 hour, dried, and then 10 parts were reacted with 10 parts of vinyl ferrocene, 50 parts of hydrogen-containing silicone oil (hydrogen content 1.0%), and 0.2 parts of isopropyl titanate (2% of the mass of vinyl ferrocene) at 83℃ for 2.5 hours. After being processed by a high-speed homogenizer (14000r / min) for 7 minutes, hybrid fibers with a length of 200±50μm were obtained. S4: Preparation of low-temperature curing microspheres: 4 parts of 2-ethyl-4-methylimidazole and 3 parts of molten PEG6001 were dispersed and emulsified at 56℃ and 1000r / min. After cooling, microspheres with a particle size of 5-10μm were obtained. S5: Preparation of high-temperature curing microcapsules: 5 parts of phenolic amine T31 and 3 parts of sebacic dihydrazide were dissolved in ethyl acetate as the core material. 3 parts of bisphenol A epoxy resin E-51 and 2 parts of diisocyanate HDI were prepolymerized at 60℃ for 30 minutes (NCO / OH molar ratio 1.1:1) to obtain the wall material. The core material was dripped into the wall material at 9000 r / min, and microcapsules with a wall thickness of 0.7 μm were formed by interfacial polymerization. S6: Preparation of self-healing microspheres: 5 parts of terminal epoxy siloxane (epoxide value 0.50) and 10 parts of ethyl acetate were used as the oil phase, and 4 parts of gelatin and 3.3 parts of gum arabic (mass ratio 1.2:1) were dissolved in 100 parts of deionized water as the aqueous phase. After re-coagulation at 50℃, the pH was adjusted to 4.3, and the mixture was cooled and cured for 2 hours to obtain microspheres with a particle size of 20-50μm. S7: Preparation of curing accelerator X: 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate were refluxed in toluene for 6 hours. The product was reacted with 1.6 parts of boron trifluoromethanesulfonate and then recrystallized with acetone. S8: Preliminary mixing: Bisphenol A epoxy resin is mixed with hybrid fibers and flake silica powder at 46°C for 0.5 hours; S9: Add functional components: Add low-temperature microspheres, high-temperature microcapsules, curing accelerator X and self-healing microspheres in sequence, and stir evenly; S10: Vacuum degassing: Degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 260r / min to obtain the finished product.

[0028] Comparative Example 1: Compared with Example 1, this comparative example did not add zinc oxide whiskers during the preparation of epoxy resin splicing material. All other steps and parameters were the same, and will not be repeated here. The final epoxy resin splicing material was obtained.

[0029] Comparative Example 2: Compared with Example 1, no hybrid fibers were added during the preparation of the epoxy resin splicing material in this comparative example. All other steps and parameters were the same, and will not be repeated here. The final epoxy resin splicing material was obtained.

[0030] Comparative Example 3: Compared with Example 1, this comparative example did not add self-healing microspheres during the preparation of epoxy resin splicing material. All other steps and parameters were the same, and will not be repeated here. Finally, the epoxy resin splicing material was obtained.

[0031] Comparative Example 4: Compared with Example 1, no curing accelerator X was added during the preparation of the epoxy resin splicing material in this comparative example. All other steps and parameters were the same, and will not be repeated here. The final epoxy resin splicing material was obtained.

[0032] Comparative Example 5: Compared with Example 1, this comparative example adds commercially available curing accelerator HEP-BF3 during the preparation of epoxy resin splicing material. All other steps and parameters are the same, and will not be repeated here. The final epoxy resin splicing material is obtained.

[0033] Performance testing was conducted according to the following procedure, with all examples and comparative examples executed simultaneously: Storage stability test: After the epoxy resins prepared in Examples 1-6 and Comparative Examples 1-5 were completed, the viscosity of the products was tested at room temperature (24°C), and then the products were stored under the following conditions: Condition A: Place in a constant temperature environment of 24 ℃ and let stand for 3 months; Condition B: Store in a -5 ℃ low-temperature chamber for 18 months.

[0034] After the storage period, all samples were brought back to 24 ℃ and their viscosity was measured using a rotational viscometer. Based on the initial viscosity, a viscosity increase of ≤50% was considered acceptable for storage.

[0035] Hardness test: After the sample was warmed, it was cast into a 6 mm thick disc and cured for 24 h under standard laboratory conditions. The hardness value was then determined using a Shore D hardness tester according to the ASTM D-2240 method.

[0036] Tensile strength and elongation test: Dumbbell-shaped test strips (2 mm thick) were cast using the same batch of rubber samples and tensile tests were performed according to ASTM D-638. The tensile strength and elongation at break were recorded.

[0037] Tensile shear strength test: According to ISO 4587 method, the adhesive sample was applied to the overlapping surface of the sandblasted aluminum sheet with an overlap length of 12.5 mm. After curing, it was stretched in a universal testing machine at a speed of 5 mm / min, and the shear strength was recorded.

[0038] Curing rate test: Following the ASTM D2240 standard method, the adhesive sample was cast into a 6mm thick circular sheet, and its Shore D hardness was measured at intervals of 0.5h, 1h, 2h, etc., at 23°C. The time required for the hardness to reach a stable value was taken as the initial curing time to determine the solidification rate.

[0039] Weather resistance life test: Thermo-oxidative aging test was conducted according to ISO18280:2010 method, with a test temperature of 150℃ and a time of 500h. After that, the shear strength retention rate was tested as the basis for life determination.

[0040] The test data are summarized in Table 1, which is used to compare the overall performance differences between Examples 1-6 and Comparative Examples 1-5.

[0041] Table 1. Overall performance test results of the examples and comparative examples

[0042] As shown in Table 1, the high-strength, long-life epoxy splicing material of this invention exhibits significant performance advantages. Zinc oxide whisker-based hybrid fibers (silanized with KH-550 and hybridized with vinyl ferrocene / hydrogen-containing silicone oil) significantly improve tensile strength (Example 1: 39 MPa vs. Comparative Example 2: 18 MPa) and elongation (Example 6: 19% vs. Comparative Example 2: 5%) through the composite effect of rigid whiskers and flexible organic segments, with the hybrid fibers contributing a 117% increase in strength. Flake-shaped silica powder (10:1 aspect ratio) effectively reduces shrinkage stress and ensures dimensional stability as a filler. Terminally epoxy-based siloxane / gelatin-arabic microspheres release epoxy-based siloxanes at microcrack sites, repairing damage through ring-opening of epoxy groups (Example 3: shear strength retention 86% vs. Comparative Example 3: 69%). The initial curing time in Example 2 was 125 min (Comparative Example 4 required 228 min), and accelerator X shortened the curing time by 45%. Example 3, after aging at 150℃ for 500 hours, retained 86% of its shear strength (compared to only 69% in Comparative Example 3), indicating a 25% increase in lifespan for the self-healing microspheres. Curing accelerator X combines curing acceleration and UV absorption, reducing ether bond photodegradation and ensuring long-term weather resistance (80%+ retention in Example 3 vs. 72% in Comparative Example 5). Comparative data conversely validated the necessity of the technology: without zinc oxide whiskers (Comparative Example 1), the tensile strength of this material decreased by 44% (22 MPa); without self-healing microspheres (Comparative Example 3), the material's weather resistance plummeted (retention rate 69%); without accelerator X (Comparative Example 4), the material's curing efficiency decreased by 70% (initial curing time 228 min).

[0043] This invention achieves a synergistic breakthrough in tensile strength (>34 MPa), toughness (elongation >15%), curing efficiency (initial curing <150 min), and durability (aging retention rate >80%) through a quadruple innovative design of hybrid fiber reinforcement (combining rigidity and flexibility), dual-temperature curing (gradient triggering), self-healing (damage response), and multifunctional accelerator (synergistic curing / weather resistance), which is significantly superior to existing technologies.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0045] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

[0046] The synthesis method of curing accelerator X (N-benzylethylenediamine / boron trifluoromethanesulfonate reaction) and the double-walled microcapsule structure (polyurethane-epoxy hybrid wall material) in this invention are key technical secrets, and can be claimed separately if necessary.

Claims

1. A high-strength, long-life epoxy splicing material, characterized in that, by weight Includes the following components: Resin matrix: 100 parts of bisphenol A epoxy resin (E-51); Reinforcing phase: 15-20 parts of zinc oxide whisker-based hybrid fiber; Filler: 25-30 parts of flake silica powder (diameter-to-thickness ratio 10:1); Low-temperature curing trigger: 5-8 parts of 2-ethyl-4-methylimidazolium / PEG600 microspheres; High-temperature curing trigger: 8-12 parts of phenolic amine-hydrazide / polyurethane-epoxy double-walled microcapsules; Multifunctional curing accelerator X: 0.5~1 part; Self-healing component: terminal epoxy siloxane / gelatin-gum arabic microspheres 3~5 parts.

2. The epoxy splicing material according to claim 1, characterized in that, The method for preparing the zinc oxide whisker-based hybrid fiber includes the following steps: (1) Mix 5-7 parts of zinc acetate, 3-5 parts of urea and 100 parts of deionized water, and hydrothermally react at 180-200℃ for 12-15 hours to obtain zinc oxide whiskers with an aspect ratio of 15-25:

1. (2) Immerse the zinc oxide whiskers in a 2-5wt% ethanol solution of silane coupling agent KH-550 for 1 hour, then filter and dry. (3) Add 10 parts of modified whiskers, 8-12 parts of vinyl ferrocene, 40-60 parts of hydrogen-containing silicone oil (hydrogen content 0.8-1.2%) and 0.1-0.3 parts of isopropyl titanate to a reactor, stir and react at 80-85℃ for 2-3 hours, and then process with a high-speed homogenizer to obtain hybrid fibers with a length of 200±50μm.

3. The epoxy splicing material according to claim 2, characterized in that, The mass ratio of zinc acetate to urea in step (1) is (1.5-1):

1.

4. The epoxy splicing material according to claim 2, characterized in that, The hydrogen-containing silicone oil mentioned in step (3) is methyl hydrogen-containing MQ silicone resin, and the amount of titanium isopropyl ester added is 1-3% of the mass of vinyl ferrocene.

5. The epoxy splicing material according to claim 2, characterized in that, The processing conditions of the high-speed homogenizer in step (3) are: rotation speed 12000-15000 r / min, processing time 5-8 minutes.

6. The epoxy splicing material according to claim 1, characterized in that, The method for preparing the low-temperature curing microspheres is as follows: 3-5 parts of 2-ethyl-4-methylimidazolium are mixed with 10-15 parts of molten polyethylene glycol PEG600, and dispersed and emulsified at 1000 r / min at 50-60℃. After cooling, microspheres with a particle size of 5-10 μm are obtained.

7. The epoxy splicing material according to claim 1, characterized in that, The preparation method of the high-temperature curing microcapsules is as follows: (1) Dissolve 6 parts of phenolic amine T314 and 2-4 parts of sebacic dihydrazide in ethyl acetate to make the core material; (2) 13 parts of bisphenol A epoxy resin E-5 and 2 parts of diisocyanate HDI were prepolymerized at 60°C for 30 minutes to obtain a polyurethane-epoxy hybrid wall material solution. (3) The core material solution is dropped into the wall material solution and stirred at a high speed of 8000-10000 r / min to form double-walled microcapsules with a wall thickness of 0.5-1 μm through interfacial polymerization. The NCO / OH molar ratio in the polyurethane-epoxy hybrid wall material is (1-1.2):

1.

8. The epoxy splicing material according to claim 1, characterized in that, The preparation method of the self-healing component is as follows: (1) Mix 5 parts of terminal epoxy siloxane (epoxide value 0.45-0.55) with 10 parts of ethyl acetate to obtain an oil phase; (2) Dissolve 4 parts of gelatin and 3 parts of gum arabic in 100 parts of deionized water to obtain an aqueous phase; (3) The oil phase is dropped into the aqueous phase at 50℃, the pH is adjusted to 4.0-4.5 for re-coagulation, the temperature is lowered to 5℃ for solidification for 2 hours, and after filtration and drying, self-healing microspheres with a particle size of 20-50μm are obtained. The mass ratio of gelatin to gum arabic is (1-1.3):

1.

9. The epoxy splicing material according to claim 1, characterized in that, The preparation method of the curing accelerator X is as follows: (1) Reflux 1 part of N-benzylethylenediamine and 2 parts of triethyl orthoformate in toluene for 6 hours. After the reaction, remove the byproduct ethanol by vacuum distillation. (2) Dissolve 1 part of the product from step (1) in THF, add 1-2 parts of boron trifluoromethanesulfonate dropwise at 0℃, raise to room temperature and stir for 24 hours. After the reaction solution is concentrated, recrystallize and purify it with any organic solvent selected from acetonitrile, n-hexane, acetone and n-heptane to obtain the target compound.

10. A method for preparing a high-strength, long-life epoxy splicing material as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) Bisphenol A epoxy resin E-51 (100 parts) is initially mixed with zinc oxide whisker-based hybrid fiber (15~20 parts) and flake silica powder (25~30 parts) at 40~50℃ for 0.5 hours; (2) Add low-temperature curing microspheres (5-8 parts) and high-temperature curing microcapsules (8-12 parts) in sequence, and stir evenly; (3) Add curing accelerator X (0.5~1 parts) and self-healing microspheres (3~5 parts), mix them, and degas for 10 minutes at a vacuum of -0.095MPa and a rotation speed of 200~300r / min to obtain the finished product.

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