Room temperature vulcanizing high temperature resistant adhesive and preparation method thereof

Abstract

The application provides a room-temperature curing high-temperature resistant adhesive and a preparation method thereof, and the preparation method comprises the following steps: modifying an epoxy resin by using trimethylphenylsilane and KH560 to obtain a modified epoxy resin; mixing and stirring the modified epoxy resin, a phenolic epoxy, KH560, an adhesion promoter, carbon fibers, colloidal graphite and hollow glass microspheres to obtain an adhesive matrix; mixing and stirring a high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol to obtain a curing agent mixture; and mixing and stirring the adhesive matrix and the curing agent mixture to obtain the room-temperature curing high-temperature resistant adhesive. The application realizes long-period service of the adhesive in a high-temperature environment.

Description

Technical Field

[0001] This application relates to the field of epoxy adhesive technology, and in particular to a room temperature curing high temperature resistant adhesive and its preparation method. Background Technology

[0002] In the aerospace industry, numerous component bonding and sealing operations require on-site construction. Since on-site assembly and field maintenance scenarios lack heating conditions, room-temperature curing adhesives have become indispensable materials in the aerospace field, adapting to assembly and maintenance scenarios without heating. Currently, most mainstream room-temperature curing adhesives on the market are prepared by blending general-purpose epoxy resins with conventional curing agents and fillers. Due to limitations in the molecular structure of raw materials and traditional manufacturing processes, the long-term operating temperature limit of the finished product is only 200-250℃, which is insufficient to meet the 300℃ high-temperature service requirements of some key components in aerospace equipment.

[0003] Conventional systems, without functionalizing the base resin, rely solely on physical blending to add fillers to improve heat resistance. This not only offers limited improvement but also easily leads to problems such as uneven filler dispersion and weak interphase bonding. Furthermore, traditional epoxy resin molecules lack highly thermally stable functional structures, resulting in insufficient thermal stability of the cross-linked network formed after curing. Above 250°C, the resin matrix is ​​prone to thermo-oxidative decomposition, adhesive layer shrinkage and cracking, and a rapid decline in bond strength, leading to bond failure. In addition, conventional blending methods cannot optimize the resin structure at the molecular level, making it difficult to overcome the 250°C temperature resistance bottleneck and simultaneously meet the dual requirements of room temperature application and 300°C high-temperature resistance, thus limiting the product's application in high-temperature aerospace components. Summary of the Invention

[0004] This application provides a room temperature curing high temperature resistant adhesive and its preparation method to solve the problems mentioned in the background art.

[0005] In a first aspect, this application provides a room temperature curing high temperature resistant adhesive, comprising the following raw materials by weight ratio: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.2; The room temperature curing high-temperature resistant adhesive also includes carbon fiber, colloidal graphite, and hollow glass microspheres. The amount of carbon fiber added is 1-10 wt% of phenolic epoxy, the amount of colloidal graphite added is 1-5 wt% of phenolic epoxy, and the amount of hollow glass microspheres added is 5-20 wt% of phenolic epoxy. The modified epoxy resin is obtained by synergistic modification of epoxy resin with trimethylphenylsilane and KH560.

[0006] Optionally, the particle size of colloidal graphite is 1-10 nm.

[0007] The particle size of carbon fiber is 100nm-10μm.

[0008] Optionally, the adhesion promoter may be selected from BYK-4511.

[0009] Optionally, the particle size of the hollow glass microspheres is 10-50 μm.

[0010] Secondly, this application provides a method for preparing a room-temperature curing, high-temperature resistant adhesive. This method, used to prepare the aforementioned room-temperature curing, high-temperature resistant adhesive, includes the following steps: (1) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, carbon fiber, colloidal graphite and hollow glass microspheres, mix and stir for 30-40 minutes to obtain adhesive matrix; (2) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 30-40 min to obtain curing agent mixture; (3) Stir the adhesive matrix and curing agent mixture for 10-40 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0011] Optionally, the preparation method of modified epoxy resin specifically includes: Epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560 and stirred at 80°C for 30-40 min. The reaction system was then heated to 140°C and diisobutyltin dilaurate catalyst was added dropwise. The temperature was maintained and stirred for 1 h to obtain the modified resin.

[0012] Optionally, during the preparation of the modified epoxy resin, after stirring, the heating rate of the reaction system to 140℃ is 5-7℃ / 10min.

[0013] Optionally, the mass ratio of epoxy resin to trimethylphenylsilane is 1:1.

[0014] Optionally, during the preparation of the modified epoxy resin, the amount of silane coupling agent KH560 added is 6 wt% of the epoxy resin.

[0015] Optionally, the amount of diisobutyltin dilaurate catalyst added is 0.1-0.2 wt% of epoxy resin, and the dropping rate of diisobutyltin dilaurate catalyst is 1 g / 5-10 min.

[0016] The room-temperature curing high-temperature resistant adhesive and its preparation method provided in this application realize the preparation of high-temperature resistant adhesive, and have the following advantages compared with the prior art: (1) This application achieves the preparation of a high-temperature resistant adhesive by mixing the above components in a specific ratio. The epoxy resin is chemically modified with trimethylphenylsilane and KH560 to improve the heat resistance and toughness of the adhesive. By using a modified epoxy resin and phenolic epoxy resin as a dual-resin matrix, the phenolic epoxy and modified epoxy resin form an interpenetrating network structure, providing rigid skeletal support under high-temperature conditions and ensuring the adhesive layer maintains structural integrity at 300℃. The KH560 silane coupling agent balances resin modification and interface reinforcement, forming a Si-O-Si crosslinking network during epoxy resin modification, improving the heat resistance of the adhesive. Simultaneously, the chemical bridging formed by KH560 effectively prevents interfacial debonding, enhancing the adhesion between the adhesive and the substrate surface. A composite filler consisting of carbon fiber, colloidal graphite, and hollow glass microspheres is used, supplemented with an adhesion promoter. Simultaneously, a multi-component synergistic curing mechanism is adopted, using high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol, to achieve room temperature curing and high-temperature service resistance of the adhesive.

[0017] (2) This invention changes the traditional preparation approach of simple physical blending. It uses trimethylphenylsilane and KH560 to synergistically chemically modify epoxy resin, and then combines it with functional fillers to prepare a composite matrix, and matches it with a special room temperature curing system. By introducing silane heat-resistant structures into the resin molecules through chemical modification, the thermal stability of the matrix is ​​improved from the root, so that the cured adhesive layer can stably withstand high temperatures of 300℃. The silane structure also plays an interfacial coupling role, improving the compatibility between the resin and the filler, avoiding filler agglomeration, and forming a dense adhesive layer structure based on the preparation process of chemical modification + compound filler. This system can be completely cured at room temperature without heating assistance. It retains the advantages of room temperature curing adhesives, such as convenient construction and suitability for on-site operations, and breaks through the temperature resistance limit of 250℃ of existing products. It significantly improves the high-temperature bonding strength, thermal stability and thermal shock resistance of the adhesive layer, effectively solving the technical problems of insufficient temperature resistance, single preparation method and easy failure under high temperature conditions of traditional room temperature curing adhesives. It can meet the bonding and use requirements of high-temperature components in the aerospace industry.

[0018] (3) Epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560 and stirred at 80°C. The reaction system was then heated to 140°C, and diisobutyltin dilaurate catalyst was added dropwise while maintaining the temperature and stirring to obtain the modified resin. By introducing the Si-O-Si main chain through modification, the thermal stability of the resin was significantly improved. The phenyl ring structure formed steric hindrance, which could hinder oxygen permeation and inhibit high-temperature oxidative degradation. At the same time, the siloxane segments had a low rotation barrier, which allowed the adhesive to maintain a certain chain mobility at high temperatures and avoid brittle fracture. Meanwhile, the heat resistance and toughness of the resin were improved by segmented temperature control and catalytic reaction process. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0020] In a first aspect, this application provides a room temperature curing high temperature resistant adhesive, comprising the following raw materials by weight ratio: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.2; The room temperature curing high-temperature resistant adhesive also includes carbon fiber, colloidal graphite, and hollow glass microspheres. The amount of carbon fiber added is 1-10 wt% of phenolic epoxy, the amount of colloidal graphite added is 1-5 wt% of phenolic epoxy, and the amount of hollow glass microspheres added is 5-20 wt% of phenolic epoxy. The modified epoxy resin is obtained by synergistic modification of epoxy resin with trimethylphenylsilane and KH560.

[0021] Specifically, this application uses trimethylphenylsilane and KH560 to chemically modify epoxy resin, then combines it with functional fillers to prepare a composite matrix, and matches it with a dedicated room temperature curing system to improve the heat resistance and toughness of the adhesive. The modified epoxy resin and phenolic epoxy resin are combined as a dual-resin matrix. The phenolic epoxy resin molecular structure contains a large number of benzene rings and a phenolic skeleton, and its cured product forms a highly cross-linked three-dimensional network structure. The phenolic epoxy resin and the modified epoxy resin form an interpenetrating network structure, providing rigid skeletal support under high temperature conditions, preventing the adhesive layer from softening and flowing. The π-π stacking effect of the benzene rings enhances the intermolecular forces; it also increases the glass transition temperature (Tg), ensuring that the adhesive layer remains in a highly elastic state or the upper part of the glass transition region at 300℃, maintaining structural integrity. KH560 silane coupling agent combines resin modification and interface reinforcement. When modifying epoxy resin, it forms a Si-O-Si cross-linked network, which improves the heat resistance of the adhesive. At the same time, the chemical bridging formed by KH560 can effectively prevent interface debonding and enhance the adhesion between the adhesive and the substrate surface.

[0022] The polar groups in adhesion promoter molecules form hydrogen bonds or coordination bonds with the substrate surface (metal oxides, ceramics, etc.), enabling the adhesive to maintain strong interfacial bonding at high temperatures through a multi-point anchoring effect. Carbon fiber, as a one-dimensional nano / micro-scale reinforcing material, can form a three-dimensional network skeleton in the colloid, bearing external stress and transferring stress from the matrix to the fiber through interfacial shear. When cracks propagate to the fiber, they deflect, bridge, and pull out, consuming a large amount of fracture energy. It also has extremely high axial thermal conductivity, forming a thermally conductive network that improves the mechanical strength and creep resistance of the adhesive.

[0023] The weak van der Waals forces between colloidal graphite layers facilitate interlayer slippage under shear forces, reducing the coefficient of friction. This allows it to synergize with carbon fibers, rapidly dispersing localized hotspots and preventing concentrated thermal degradation. The interlayer slippage of graphite releases stress and, to some extent, repairs microcracks, contributing to improved high-temperature self-healing properties of adhesives. The hollow structure of hollow glass microspheres significantly reduces the thermal conductivity of the adhesive layer, minimizing rapid heat transfer and protecting the internal resin. Furthermore, the spherical structure disperses stress concentration, improving thermal shock resistance.

[0024] Simultaneously, a multi-component synergistic curing mechanism is employed, utilizing a high-temperature resistant epoxy curing agent, tetraethylenepentamine, and 2,4,6-tris(dimethylaminomethyl)phenol. Tetraethylenepentamine provides rapid room-temperature curing capability, the high-temperature resistant epoxy curing agent provides high-temperature crosslinking density and thermal stability, and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) activates epoxy groups through hydrogen bonding, lowering the reaction activation energy and catalyzing the reaction of epoxy groups with amine and hydroxyl groups, thus accelerating curing. The synergistic effect of tetraethylenepentamine and DMP-30 ensures that workable strength is achieved within 4-8 hours at 20-25℃, meeting on-site construction requirements. The aromatic crosslinking structure formed by the high-temperature resistant curing agent is not easily broken at 300℃, achieving room-temperature curing and high-temperature serviceability of the adhesive. The high-temperature resistant epoxy curing agent is BD11, purchased from Xiangyang Baidun Protective Coating Materials Co., Ltd.

[0025] Preferably, the epoxy resin is selected from AG-80 epoxy resin or AG-90 epoxy resin.

[0026] This application achieves the preparation of a high-temperature resistant adhesive by mixing the above components in a specific ratio. Chemical modification of epoxy resin with trimethylphenylsilane and KH560 enhances the adhesive's heat resistance and toughness. By using a blend of modified epoxy resin and phenolic epoxy as a dual-resin matrix, the phenolic epoxy and modified epoxy resin form an interpenetrating network structure, providing rigid skeletal support under high-temperature conditions and ensuring the adhesive layer maintains structural integrity at 300℃. The KH560 silane coupling agent balances resin modification and interface reinforcement, forming a Si-O-Si crosslinked network during epoxy resin modification, improving the adhesive's heat resistance. Simultaneously, the chemical bridging formed by KH560 effectively prevents interfacial debonding, enhancing the adhesion between the adhesive and the substrate surface. A multi-component filler blend of carbon fiber, colloidal graphite, and hollow glass microspheres, supplemented with an adhesion promoter, is used. Simultaneously, a multi-component synergistic curing mechanism is adopted, using high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol, to achieve room temperature curing and high-temperature service resistance of the adhesive.

[0027] Optionally, the particle size of colloidal graphite is 1-10 nm.

[0028] Optionally, the particle size of the carbon fiber is 100nm-10μm.

[0029] Optionally, the adhesion promoter may be selected from BYK-4511.

[0030] Optionally, the particle size of the hollow glass microspheres is 10-50 μm.

[0031] Secondly, this application provides a method for preparing a room-temperature curing, high-temperature resistant adhesive. This method, used to prepare the aforementioned room-temperature curing, high-temperature resistant adhesive, includes the following steps: (1) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, carbon fiber, colloidal graphite and hollow glass microspheres, mix and stir for 30-40 minutes to obtain adhesive matrix; (2) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 30-40 min to obtain curing agent mixture; (3) Stir the adhesive matrix and curing agent mixture for 10-40 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0032] Specifically, modified epoxy resin and phenolic epoxy resin are fully miscible under shear stress, forming a homogeneous or microphase-separated blend system. KH560 is uniformly dispersed in the resin matrix, with some epoxy groups undergoing pre-reaction with the hydroxyl groups in the resin, and some methoxy groups beginning hydrolysis, preparing for subsequent reactions with the filler surface. High-shear stirring ensures the resin fully wets the surfaces of carbon fibers, colloidal graphite, and hollow glass microspheres; BYK-4511 is oriented at the filler-resin interface, reducing interfacial tension; carbon fibers undergo a certain degree of fiber orientation and dispersion under shear force, forming a preliminary network structure. Furthermore, high shear force facilitates the exfoliation and dispersion of graphite sheets in the resin, increasing the specific surface area and improving thermal conductivity and lubrication efficiency. Thorough premixing ensures uniform distribution of each component at the molecular / nanoscale level, avoiding concentrated thermal degradation due to localized component inhomogeneity at high temperatures.

[0033] Tetraethylenepentamine and the high-temperature curing agent are uniformly mixed under shear stress to adjust the overall amine value and reactivity. The tertiary amine groups in DMP-30 form hydrogen-bonded complexes with the amine curing agent, pre-activating the curing agent molecules and preparing them for subsequent rapid curing. By adjusting the ratio of the three curing agent components, a balance is achieved between the room temperature reaction rate and the high-temperature crosslinking density. The uniform mixing of the curing agent system ensures that the curing reaction occurs synchronously throughout the entire adhesive layer, avoiding internal stress caused by uneven local curing; catalytic pre-activation makes the curing reaction more complete, increases the crosslinking density, and thus improves the high-temperature strength.

[0034] Finally, mix the adhesive matrix and the curing agent mixture for 10-40 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0035] Optionally, the preparation method of modified epoxy resin specifically includes: Epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560 and stirred at 80°C for 30-40 min. The reaction system was then heated to 140°C and diisobutyltin dilaurate catalyst was added dropwise. The temperature was maintained and stirred for 1 h to obtain the modified resin.

[0036] Specifically, the epoxy groups in the epoxy resin molecule and the glycidyl ether group of KH560 form a preliminary compatible system. The phenyl and methyl groups of trimethylphenylsilane penetrate into the interchain gaps of the epoxy resin, reducing the viscosity of the system and promoting molecular-level dispersion. Under the catalytic reaction at 140℃ and in the presence of diisobutyltin dilaurate, the methoxy groups of KH560 undergo hydrolysis and condensation. The trimethoxysilane group in the KH560 molecule hydrolyzes in the presence of trace amounts of water, generating silanol groups (-Si(OH)3), which then condense with the hydroxyl or epoxy groups on the epoxy resin chain segments to form Si-OC or Si-O-Si crosslinked structures. The grafting reaction of trimethylphenylsilane: The Si-H bonds or active end groups in phenylsilane react with the hydroxyl groups of the epoxy resin under the action of a catalyst, introducing a heat-resistant phenylsiloxane structure into the epoxy resin backbone. The introduced Si-O-Si backbone significantly improves the resin's thermal stability. The phenyl ring structure creates steric hindrance, hindering oxygen penetration and inhibiting high-temperature oxidative degradation. Simultaneously, the siloxane segments possess low rotational barriers, allowing the adhesive to maintain a certain degree of chain mobility at high temperatures, preventing brittle fracture. Segmented temperature control and catalytic reaction processes further enhance the resin's heat resistance and toughness.

[0037] Optionally, during the preparation of the modified epoxy resin, after stirring, the heating rate of the reaction system to 140℃ is 5-7℃ / 10min.

[0038] Specifically, controlling the heating rate and maintaining a stable temperature rise avoids violent reactions caused by excessively rapid heating. Temperature control is beneficial to the quality stability of modified epoxy resin, which in turn helps the adhesive to have better high-temperature stability.

[0039] Optionally, the mass ratio of epoxy resin to trimethylphenylsilane is 1:1.

[0040] Optionally, the amount of silane coupling agent KH560 added is 6 wt% of the epoxy resin.

[0041] Optionally, the amount of diisobutyltin dilaurate catalyst added is 0.1-0.2 wt% of epoxy resin, and the dropping rate of diisobutyltin dilaurate catalyst is 1 g / 5-10 min.

[0042] The following are embodiments and effect test examples of this application, further describing the technical solution and technical effects of the present invention. However, the scope of protection of the present invention is not limited to these embodiments. Any changes or equivalent substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention. Furthermore, for those embodiments where specific technical operation steps or conditions are not specified, they are performed according to the techniques or conditions described in general literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0043] Example 1

[0044] A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: (1) Preparation of modified epoxy resin: AG-80 epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560, and stirred at 80℃ for 40 min. The reaction system was then heated to 140℃ at a rate of 7℃ / 10 min, and diisobutyltin dilaurate catalyst was added dropwise at a rate of 1 g / 5 min. The mixture was stirred for 1 h while maintaining the temperature to obtain the modified resin. The mass ratio of epoxy resin to trimethylphenylsilane was 1:1, the amount of KH560 added was 6 wt% of the epoxy resin, and the amount of diisobutyltin dilaurate catalyst added was 0.1 wt% of the epoxy resin.

[0045] (2) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter (BYK-4511), carbon fiber (particle size 100nm-1μm), colloidal graphite (particle size 1-5nm), and hollow glass microspheres (particle size 10-20μm) and mix for 40min to obtain adhesive matrix; (3) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 30 min to obtain curing agent mixture; (4) Stir the adhesive matrix and the curing agent mixture for 10 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0046] The adhesive comprises the following raw materials by weight ratio: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high-temperature epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.2; carbon fiber added at 1 wt% of phenolic epoxy; colloidal graphite added at 1 wt% of phenolic epoxy; and hollow glass microspheres added at 5 wt% of phenolic epoxy.

[0047] Example 2

[0048] A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: (1) Preparation of modified epoxy resin: AG-80 epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560, and stirred at 80℃ for 35 min. The reaction system was then heated to 140℃ at a rate of 6℃ / 10 min, and diisobutyltin dilaurate catalyst was added dropwise at a rate of 1 g / 10 min. The mixture was stirred for 1 h while maintaining the temperature to obtain the modified resin. The mass ratio of epoxy resin to trimethylphenylsilane was 1:1, the amount of KH560 added was 6 wt% of the epoxy resin, and the amount of diisobutyltin dilaurate catalyst added was 0.2 wt% of the epoxy resin.

[0049] (2) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter (BYK-4511), carbon fiber (particle size 1μm-5μm), colloidal graphite (particle size 5-10nm), and hollow glass microspheres (particle size 20-50μm) and mix for 30min to obtain the adhesive matrix; (3) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 35 min to obtain curing agent mixture; (4) Mix the adhesive matrix and the curing agent mixture for 30 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0050] The adhesive comprises the following raw materials by weight ratio: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high-temperature epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.2; carbon fiber added at 5 wt% of phenolic epoxy; colloidal graphite added at 3 wt% of phenolic epoxy; and hollow glass microspheres added at 15 wt% of phenolic epoxy.

[0051] Example 3

[0052] A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: (1) Preparation of modified epoxy resin: AG-80 epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560, and stirred at 80℃ for 35 min. The reaction system was then heated to 140℃ at a rate of 5℃ / 10 min, and diisobutyltin dilaurate catalyst was added dropwise at a rate of 1 g / 5 min. The mixture was stirred for 1 h while maintaining the temperature to obtain the modified resin. The mass ratio of epoxy resin to trimethylphenylsilane was 1:1, the amount of KH560 added was 6 wt% of the epoxy resin, and the amount of diisobutyltin dilaurate catalyst added was 0.15 wt% of the epoxy resin.

[0053] (2) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter (BYK-4511), carbon fiber (particle size 5μm-10μm), colloidal graphite (particle size 5-10nm), and hollow glass microspheres (particle size 20-50μm) and mix for 40min to obtain the adhesive matrix; (3) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 30 min to obtain curing agent mixture; (4) Mix the adhesive matrix and the curing agent mixture for 40 minutes to obtain a room temperature curing high temperature resistant adhesive.

[0054] The adhesive comprises the following raw materials by weight ratio: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high-temperature epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.2; carbon fiber added at 10 wt% of phenolic epoxy; colloidal graphite added at 5 wt% of phenolic epoxy; and hollow glass microspheres added at 20 wt% of phenolic epoxy.

[0055] Comparative Example 1 A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: The difference from Example 2 is that: The epoxy resin is not modified; AG-80 epoxy resin is used directly.

[0056] Comparative Example 2 A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: The difference from Example 2 is that: The adhesive matrix does not contain phenolic epoxy.

[0057] Comparative Example 3 A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: The difference from Example 2 is that: The curing agent mixture does not contain high-temperature resistant epoxy curing agents.

[0058] Comparative Example 4 A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: The difference from Example 2 is that: The curing agent mixture does not contain tetraethylenepentamine.

[0059] Comparative Example 5 A method for preparing a room-temperature curing, high-temperature resistant adhesive, comprising the following steps: The difference from Example 2 is that: (1) Preparation of modified epoxy resin: AG-80 epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560. The reaction system was heated to 140°C at a heating rate of 6°C / 10min, and diisobutyltin dilaurate catalyst was added dropwise at a dropping rate of 1g / 10min. The temperature was maintained and the mixture was stirred for 1h to obtain the modified resin.

[0060] Experimental Example 1 Peel strength test Adhesives were successfully prepared in Examples 1-3, and the adhesives provided in Examples 1-3 and Comparative Examples 1-5 were bonded to test pieces. The peel strength of the adhesives provided in Examples 1-3 and Comparative Examples 1-5 was tested at room temperature, 300℃, and 350℃, respectively. At least three parallel tests were set up for each experiment, and the average value was taken. The results are shown in Table 1.

[0061] Test standards: Room temperature peel strength: GJB446-1988 "Test method for peel strength of adhesives at high temperature 90° (metal to metal)"; 300°C and 350°C peel strength: GJB447-1988 "Test method for peel strength of adhesives at high temperature 90° (metal to metal)".

[0062] Table 1

[0063] By comparing Examples 1-3 with Comparative Examples 1-5, it was found that without the addition of a high-temperature resistant epoxy curing agent, the peel strength of the adhesive at temperatures of 300°C and above was significantly reduced. It was also found that the chemical modification of AG80 epoxy resin by trimethylphenylsilane and KH560, and the use of a compound of modified epoxy resin and phenolic epoxy as a dual-resin matrix, facilitated better peel strength in the adhesive. The interpenetrating network structure formed by the phenolic epoxy and modified epoxy resin provided rigid skeletal support under high-temperature conditions, preventing the adhesive layer from softening and flowing. Simultaneously, the π-π stacking effect of the benzene rings enhanced intermolecular forces, ensuring that the adhesive layer remained in the high-elasticity state or the upper part of the glass transition region at 300°C, maintaining structural integrity.

[0064] Experimental Example 2 Shear strength testing The shear strength of the adhesives provided in Examples 1-3 and Comparative Examples 1-5 was tested at room temperature and 300°C, respectively.

[0065] The adhesive bonding test specimens were prepared according to GB / T7124-2008 "Adhesives - Determination of tensile shear strength (rigid material to rigid material)". The curing conditions for the adhesive bonding test specimens were as follows: heating rate ≤ 2℃ / min, curing at 120℃±5℃ for 90 min, cooling rate ≤ 1℃ / min, and after reaching 70℃, cooling to room temperature in the oven. The curing pressure was ≤ 0.1 MPa (contact pressure). Shear strength testing was performed using a universal testing machine. At least three parallel tests were conducted for each experiment, and the average value was taken. The results are shown in Table 2.

[0066] Table 2

[0067] As shown in Table 2, the adhesive provided in this application exhibits excellent shear strength. Through synergistic modification with organosilicon and a dual-epoxy composite matrix (compared to Comparative Example 1), the adhesive demonstrates stronger heat resistance, better toughness, and less mechanical strength degradation at high temperatures. Furthermore, by employing a ternary compound curing system, the drawbacks of slow room temperature curing of traditional high-temperature epoxy adhesives and poor heat resistance of ordinary room-temperature curing adhesives are overcome, allowing the adhesive to balance room-temperature application efficiency with high-temperature performance.

[0068] Experimental Example 3 Acid-resistant atmospheric test The shear strength and peel strength of the adhesives provided in Examples 1-3 and Comparative Examples 1-5 were tested under acidic conditions. Acidic atmosphere: solution pH 3.5, temperature 35±2℃, solution sedimentation rate (1-3) mL / (80cm²). 2 Spraying for 2 hours and storing for 7 days constitutes one cycle, with a total of 4 cycles. Other procedures shall be carried out in accordance with military standard GJB150.28-2009.

[0069] Each experiment had at least three parallel trials, and the average value was taken. The results are shown in Table 3.

[0070] Table 3

[0071] As shown in Table 3, the adhesive provided in this application still exhibits good mechanical properties under acidic conditions. Therefore, the adhesive of this application has excellent acid resistance and can be applied to more complex environments. Furthermore, by comparing Examples 1-3 in Tables 1-3 with Comparative Examples 1 and 5, it was found that the synergistic modification of epoxy resin with trimethylphenylsilane and KH560 introduces a silane-based heat-resistant structure into the resin molecule, fundamentally improving the thermal stability of the matrix. This allows the cured adhesive layer to stably withstand high temperatures of 300℃. Simultaneously, the preparation process relying on chemical modification and compound fillers forms a dense adhesive layer structure, further enhancing the mechanical properties of the adhesive. Furthermore, the combination of segmented temperature control and catalytic reaction processes in the preparation of modified epoxy resin enhances the resin's heat resistance and toughness, thereby positively impacting the mechanical properties of the adhesive at high temperatures. This results in the adhesive possessing advantages such as high temperature resistance, high strength, wear resistance, lightweight, and low shrinkage, solving the problems of insufficient heat resistance, high brittleness, limited functionality of single fillers, and difficulty in achieving balanced performance of the curing system in traditional room temperature curing epoxy adhesives.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A room temperature curing, high-temperature resistant adhesive, characterized in that, The raw materials included by weight are: modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, high-temperature epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 20:13:0.89:0.48:4:1.6:1.

2. The room-temperature curing, high-temperature resistant adhesive further includes carbon fiber, colloidal graphite, and hollow glass microspheres. The amount of carbon fiber added is 1-10 wt% of the phenolic epoxy, the amount of colloidal graphite added is 1-5 wt% of the phenolic epoxy, and the amount of hollow glass microspheres added is 5-20 wt% of the phenolic epoxy. The modified epoxy resin is obtained by synergistic modification of epoxy resin with trimethylphenylsilane and KH560.

2. The room temperature curing high-temperature resistant adhesive according to claim 1, characterized in that, The colloidal graphite has a particle size of 1-10 nm.

3. The room temperature curing high-temperature resistant adhesive according to claim 1, characterized in that, The carbon fiber has a particle size of 100nm-10μm.

4. The room temperature curing high-temperature resistant adhesive according to any one of claims 1-3, characterized in that, The hollow glass microspheres have a particle size of 10-50 μm.

5. A method for preparing a room-temperature curing, high-temperature resistant adhesive, characterized in that, The preparation method is used to prepare the room temperature curing high-temperature resistant adhesive according to any one of claims 1-4, and the preparation method includes the following steps: (1) According to the weight ratio, take modified epoxy resin, phenolic epoxy, KH560, adhesion promoter, carbon fiber, colloidal graphite and hollow glass microspheres, mix and stir for 30-40 minutes to obtain adhesive matrix; (2) Take high-temperature resistant epoxy curing agent, tetraethylenepentamine and 2,4,6-tris(dimethylaminomethyl)phenol by weight ratio and stir for 30-40 min to obtain curing agent mixture; (3) Stir the adhesive matrix and the curing agent mixture for 10-40 minutes to obtain the room temperature curing high temperature resistant adhesive.

6. The method for preparing the room temperature curing high-temperature resistant adhesive according to claim 5, characterized in that, The preparation method of the modified epoxy resin specifically includes: Epoxy resin was mixed with trimethylphenylsilane and silane coupling agent KH560 and stirred at 80°C for 30-40 min. The reaction system was then heated to 140°C and diisobutyltin dilaurate catalyst was added dropwise. The temperature was maintained and stirred for 1 h to obtain the modified resin.

7. The method for preparing the room temperature curing high-temperature resistant adhesive according to claim 6, characterized in that, During the preparation of the modified epoxy resin, after stirring, the heating rate of the reaction system to 140°C is 5-7°C / 10min.

8. The method for preparing the room temperature curing high-temperature resistant adhesive according to claim 6, characterized in that, The mass ratio of the epoxy resin to trimethylphenylsilane is 1:

1.

9. The method for preparing the room temperature curing high-temperature resistant adhesive according to claim 6, characterized in that, In the preparation process of the modified epoxy resin, the amount of silane coupling agent KH560 added is 6 wt% of the epoxy resin.

10. The method for preparing the room temperature curing high-temperature resistant adhesive according to claim 6, characterized in that, The amount of the diisobutyltin dilaurate catalyst added is 0.1-0.2 wt% of the epoxy resin, and the dropping rate of the diisobutyltin dilaurate catalyst is 1 g / 5-10 min.

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