Preparation method and application of adhesive

Abstract

The invention provides a preparation method and application of an adhesive. A part of hydroxyl groups of tannic acid are subjected to acyl chloride esterification and then grafted with triethylene tetramine, modified tannic acid is prepared as a rust conversion agent, and the surface of nano iron powder is coated with the modified tannic acid to prepare the magnetic response material. When the material is added into an epoxy adhesive system, a rust layer can be derusted while bonding is carried out under the action of a magnetic field, a polyamine chain segment in the modified tannic acid can also participate in an epoxy curing reaction, and the interface crosslinking strength is improved. The adhesive prepared by the method is simple and convenient to construct, and reliable bonding of iron-based materials can be realized without polishing and derusting. The invention also provides application of the adhesive prepared by the method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to a preparation method of an adhesive and application thereof. BACKGROUND

[0002] Epoxy adhesive has been widely used in the connection and repair of metal structural parts, especially in the industrial fields of steel structure and rail transportation, due to its high bonding strength, excellent dimensional stability after curing, and good corrosion resistance, heat resistance and weather resistance. Among them, iron and its alloys are common structural materials, and their surfaces are prone to oxidation and corrosion, forming a rust layer, which significantly weakens the interfacial bonding strength between the adhesive and the substrate, affecting the bonding durability and structural safety.

[0003] To ensure the bonding performance of epoxy adhesive on iron-based substrates, the existing technology usually needs to pretreat the rusted surface, such as sandblasting, polishing, pickling, etc., to remove the surface rust layer and enhance the interfacial bonding force. However, this kind of physical or chemical rust removal method is complicated, time-consuming and labor-intensive, especially when the component structure is complex, there are dead angles or non-detachable positions, it is difficult to achieve comprehensive and effective rust removal, which limits the application of epoxy structural adhesive in iron-based materials.

[0004] Therefore, it is necessary to develop an epoxy adhesive suitable for direct bonding on the surface of rusted iron-based substrates, which can achieve firm bonding without additional rust removal treatment, to simplify the construction process and improve the bonding efficiency. SUMMARY

[0005] The present application provides a preparation method of an adhesive, which can achieve stable bonding on the surface of iron-based materials without complete rust removal, has excellent bonding strength and interfacial bonding performance, and is particularly suitable for steel structural components, metal repair and other application scenarios with high requirements for construction convenience and service durability.

[0006] The present application also provides an adhesive.

[0007] The present application also provides the application of the above-mentioned adhesive

[0008] Specifically, the first aspect of the present application relates to a preparation method of an adhesive, comprising the following steps:

[0009] S1, reacting tannic acid with chloroacetyl chloride and controlling the excess of tannic acid to obtain chloroacetylated tannic acid;

[0010] S2, reacting the chloroacetylated tannic acid with triethylenetetramine to obtain modified tannic acid;

[0011] S3, dissolving the modified tannic acid in alcohol, adding a dispersing agent and nano iron powder, stirring, and removing the solvent under reduced pressure to obtain iron powder coated with iron powder;

[0012] S4, mixing the coated iron powder with preparation raw materials including a first thixotropic agent and an amine curing agent to obtain the B component; and mixing preparation raw materials including a bisphenol A type epoxy resin, a second thixotropic agent, a toughening agent and a coupling agent to obtain the A component.

[0013] The method for preparing the adhesive according to the first aspect of the embodiments of the present application has at least the following beneficial effects:

[0014] The modified tannic acid obtained by grafting tannic acid with triethylenetetramine retains functional groups such as phenolic hydroxyl groups that can complex with iron ions, and has excellent metal complexing capacity. On the other hand, the nucleophilic amine group structure with reactivity is introduced, which enhances the chemical compatibility and interfacial interaction with the epoxy adhesive system.

[0015] The coated iron powder can be guided and enriched on the surface or micro-gap area of the iron-based material by means of a magnetic field during use. The modified tannic acid in the coating layer can complex with rust to generate a dense complex film in situ at the interface under the condition of incomplete rust removal, thereby enhancing the bonding force of the interface and significantly improving the structural bonding strength and service stability.

[0016] Therefore, the adhesive prepared by the method has the advantage of stable bonding without complete rust removal, and can be applied to complex structures, narrow gaps, dead angles and other areas that are difficult to treat by traditional rust removal methods. The method significantly simplifies the on-site construction process, reduces the intensity of pretreatment process, improves the construction efficiency and structural durability, and is particularly suitable for steel structure components, metal repair, assembly and reinforcement, and other application scenarios with high service reliability requirements.

[0017] According to some embodiments of the present application, in step S1, the molar ratio of tannic acid to chloroacetyl chloride is 1:3-6, for example, 1:3, 1:4, 1:5 or 1:6.

[0018] According to some embodiments of the present application, in step S1, the reaction temperature is 0-25℃, and the reaction time is 6-12h. For example, the reaction temperature is 0℃, 5℃, 15℃ or 25℃, and the reaction time is 6h, 8h, 10h or 12h.

[0019] According to some embodiments of the present application, in step S1, the reaction is carried out in the presence of a solvent and a catalyst.

[0020] Preferably, in step S1, the solvent is a mixed solvent of DMF (N,N-dimethylformamide) and DCM (dichloromethane), and the volume ratio of DMF to DCM is 1-2:1, for example, 1:1, 1.5:1 or 2:1. The amount of the solvent can be appropriately adjusted according to the reaction requirements and experience.

[0021] Preferably, in step S1, the catalyst is selected from triethylamine.

[0022] Preferably, in step S1, the catalyst is used in an amount of 1-1.2 times the molar amount of chloroacetyl chloride.

[0023] Preferably, in step S1, the reaction comprises: first mixing tannic acid, solvent and catalyst, then adding chloroacetyl chloride dropwise at 0-5°C, and after the addition is completed, warming to 10-25°C and reacting for 6-10 hours.

[0024] According to some embodiments of the present application, in step S1, the reaction is carried out under an inert atmosphere.

[0025] According to some embodiments of the present application, in step S2, the molar ratio of chloroacetyl groups in the chloroacetylated tannic acid to triethylenetetramine is 1:1.5-2, for example 1:1.5, 1:1.6, 1:1.8, 1:2.

[0026] According to some embodiments of the present application, in step S2, the reaction is carried out in the presence of a solvent and a catalyst.

[0027] Preferably, in step S2, the solvent is selected from DMF or DMSO. The present application does not limit the amount of solvent used, for example, the amount of solvent used can be 40-60 mL / g based on the mass of the chloroacetylated tannic acid.

[0028] Preferably, in step S2, the catalyst is selected from triethylamine or potassium carbonate.

[0029] Preferably, in step S2, the catalyst is used in an amount of 1-1.2 times the molar amount of chloroacetyl groups in the chloroacetylated tannic acid.

[0030] Preferably, in step S2, the reaction temperature is 50-70°C and the reaction time is 6-12 hours. For example, the reaction temperature is 50°C, 60°C, 70°C, and the reaction time is 6 hours, 8 hours, 10 hours, 12 hours.

[0031] According to some embodiments of the present application, in step S2, the reaction is carried out under an inert atmosphere.

[0032] According to some embodiments of the present application, in step S3, the alcohol is ethanol or isopropanol.

[0033] According to some embodiments of the present application, the mass-to-volume ratio of the modified tannic acid to the alcohol is 1 g / 20-50 mL, for example 1 g / 20 mL, 1 g / 30 mL, 1 g / 40 mL, 1 g / 50 mL.

[0034] According to some embodiments of the present application, the dispersant is at least one of PVP, polyvinyl alcohol, and sodium dodecyl benzene sulfonate.

[0035] According to some embodiments of the present application, the dispersant is used in an amount of 2% to 10% of the mass of the modified tannic acid, for example 2%, 4%, 6%, 8%, or 10%.

[0036] According to some embodiments of the present application, the nano-iron powder has a particle size of 20 to 80 nm.

[0037] According to some embodiments of the present application, the mass ratio of the modified tannic acid to the nano-iron powder is 1:4 to 1:10, for example 1:4, 1:5, 1:6, 1:8, or 1:10.

[0038] According to some embodiments of the present application, the stirring process is performed with ultrasonic treatment.

[0039] Preferably, the ultrasonic treatment is performed for 0.5 to 1 hour, and the stirring is performed for 0.5 to 1 hour. The present application does not particularly limit the ultrasonic treatment conditions, for example, ultrasonic treatment with a frequency of 20 to 40 kHz and a power of 100 to 500 W can be used, and the specific conditions can be selected and adjusted by a person skilled in the art in combination with actual conditions and experience.

[0040] According to some embodiments of the present application, the amine curing agent is at least one of a modified alicyclic amine and a modified polyether amine.

[0041] According to some embodiments of the present application, the toughening agent is carboxyl-terminated liquid butadiene-acrylonitrile rubber (CTBN).

[0042] According to some embodiments of the present application, the carboxyl-terminated liquid butadiene-acrylonitrile rubber has a number average molecular weight of 3000 to 6000.

[0043] According to some embodiments of the present application, the first and second thixotropic agents are independently at least one of organic bentonite and fumed silica.

[0044] According to some embodiments of the present application, the coupling agent is at least one of KH550 and KH560.

[0045] According to some embodiments of the present application, the B component comprises, in parts by mass, 85 to 90 parts of the amine curing agent, 5 to 10 parts of the coated iron powder, and 1 to 3 parts of the second thixotropic agent.

[0046] According to some embodiments of the present application, the A component comprises, in parts by mass, 100 parts of the bisphenol A type epoxy resin, 10 to 15 parts of the toughening agent, 1 to 3 parts of the first thixotropic agent, and 0.5 to 1.5 parts of the coupling agent.

[0047] According to some embodiments of the present application, dispersants and defoamers are added to the A component and the B component. The amount of dispersants and defoamers, for example, is 0.1% to 0.5% of the mass of the A component or the B component.

[0048] According to some embodiments of the present application, the mass ratio of the A component to the B component is 100:60 to 100:70.

[0049] The second aspect of the embodiments of the present application relates to the adhesive prepared by the preparation method described above.

[0050] The adhesive has excellent interface adaptability and structural bonding performance, and can form a bonding interface with high strength and good compactness on the surface of the iron-based material after curing. It not only has high shear strength, but also has good corrosion resistance of the formed rust conversion complex layer. Compared with traditional epoxy structural adhesives, the adhesive has low requirements for the surface pretreatment of iron-based materials, can realize stable bonding on the surface of iron-based materials with rust oxidation, is suitable for complex structures, irregular surfaces or difficult rust removal working conditions, and effectively improves the assembly reliability and service life of iron-based materials.

[0051] The third aspect of the embodiments of the present application relates to the application of the adhesive described above in the bonding of iron-based materials.

[0052] The adhesive can be widely used in the installation and repair of steel structure components, the reinforcement of bridge steel plates, the packaging of metal shells, the bonding of rail transit equipment, the corrosion prevention and reinforcement of power facilities, and other industrial scenes, and is especially suitable for on-site construction of components with limited surface treatment or dead angle areas. It simplifies the construction process while ensuring the structural bonding strength, and improves the adaptability and maintenance efficiency of large steel structures or iron-based parts in harsh environments.

[0053] According to some embodiments of the present application, the application comprises the following steps: applying the adhesive to the surface of the iron-based material to be bonded, applying an external magnetic field with a magnetic induction intensity of 0.1 to 0.5 T, a magnetic field action time of 10 to 60 min, and a magnetic field direction perpendicular to the surface of the iron-based material; and after removing the magnetic field, continuing to stand until the adhesive is completely cured.

[0054] In this document, the term "room temperature" refers to 23±2℃.

[0055] In this document, the numerical ranges referred to include the end points and cover any sub-range within the range, for example, a range obtained by any combination of the specifically listed numerical values.

[0056] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. DETAILED DESCRIPTION

[0057] The following describes embodiments of the present application in detail. The embodiments described below are exemplary and are intended to explain the present application, but should not be construed as limiting the present application.

[0058] In the following examples, the amine curing agent is selected from modified alicyclic amines, Riche R-2026.

[0059] Dispersant: PVP K90, powder.

[0060] Carboxyl liquid nitrile rubber: number average molecular weight of 3000.

[0061] Organic bentonite: ZT-S, Hangzhou Zuotu New Materials Co., Ltd.

[0062] Dispersant: BYK-111.

[0063] Defoaming agent: BYK-088.

[0064] In the examples, the specific conditions are not specified, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0065] Example 1

[0066] A method for preparing an adhesive, comprising the following steps:

[0067] 1. Preparation of modified tannic acid

[0068] (1.1) Tannic acid, DMF / DCM mixed solvent (volume ratio 1.5:1, tannic acid to solvent mass volume ratio 1g:20mL), triethylamine were added to a three-necked flask and mixed. Under nitrogen protection, chloroacetyl chloride was slowly added at 0°C under ice bath conditions, wherein the molar ratio of tannic acid to chloroacetyl chloride was controlled to be 1:4, and the amount of triethylamine was 1.1 times the molar amount of chloroacetyl chloride; after the addition was completed, the temperature was raised to 15°C, and the reaction was stirred for 8h. Then an equal volume of ice water was added to the reaction solution, stirred thoroughly, removed the by-product, and then added an appropriate amount of DCM for extraction. After shaking and mixing, the mixture was allowed to stand and separate into two layers. The lower organic phase was washed with distilled water until it was neutral, dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure to obtain chloroacetylated tannic acid.

[0069] (1.2) The chloroacetylated tannic acid was dissolved in an appropriate amount of DMF and transferred to a reaction flask. Triethylenetetramine (molar ratio of chloroacetyl group to triethylenetetramine was 1:1.8) was added, and additional triethylamine (1.1 times the molar amount of chloroacetyl group) was added as an acid trapping agent. The reaction was carried out at 60°C under nitrogen atmosphere for 10h to obtain modified tannic acid.

[0070] 2. Preparation of coated iron powder

[0071] (2.1) Dissolve 1.0 g of the modified tannic acid described above in 30 mL of ethanol, add 0.08 g of PVP K90 powder (8% of the mass of the modified tannic acid), and ultrasonically treat (30 kHz, 300 W) for 20 min to fully dissolve and disperse.

[0072] (2.2) Add 8 g of nano-iron powder (particle size 50 nm, mass ratio of modified tannic acid to iron powder 1:7), continue ultrasonic treatment and stirring for 30 min, and remove the solvent by distillation under reduced pressure to obtain the coated iron powder.

[0073] 3. Adhesive preparation:

[0074] (3.1) Component A: Add bisphenol A type epoxy resin 100 g, carboxyl-terminated liquid nitrile rubber 12 g, fumed silica 2 g, KH560 1 g, BYK-111 0.3 g, and BYK-088 0.3 g in sequence, and stir to obtain Component A, which is ready for packaging.

[0075] (3.2) Component B: Take modified alicyclic amine curing agent (Riche R-2026) 88 g, add the coated iron powder obtained in step (3) 8 g, organic bentonite (ZT-S) 2 g, BYK-111 0.3 g, and BYK-088 0.3 g, and stir to obtain Component B, which is ready for packaging.

[0076] Example 2

[0077] A method for preparing an adhesive, comprising the following steps:

[0078] 1. Preparation of modified tannic acid

[0079] (1.1) Add tannic acid, DMF / DCM mixed solvent (volume ratio 1.5:1, mass volume ratio of tannic acid to solvent 1 g:20 mL), and triethylamine into a three-necked flask and mix. Under nitrogen protection, slowly drop chloroacetyl chloride at 0°C under ice bath conditions, wherein the molar ratio of tannic acid to chloroacetyl chloride is controlled to be 1:4, and the amount of triethylamine is 1.1 times the molar amount of chloroacetyl chloride; after the dropping is completed, the temperature is raised to 15°C, and stirring is performed for 8 h. Then, an equal volume of ice water is added to the reaction solution, stirred thoroughly, and the byproduct is removed, and then an appropriate amount of DCM is added for extraction, the mixture is shaken and mixed, and then allowed to stand to separate into layers, the lower organic phase is separated, washed with distilled water until neutral, dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure to obtain chloroacetylated tannic acid.

[0080] (1.2) The chloroacetylated tannic acid was dissolved in DMF (50 mL / g of chloroacetylated tannic acid), transferred into a reaction bottle, triethylenetetramine was added (molar ratio of chloroacetyl group to triethylenetetramine was 1:1.8), and triethylamine (1.1 times of the molar amount of chloroacetyl group) was additionally added as an acid capturing agent, and reacted at 60°C for 10 h under a nitrogen atmosphere to obtain a modified tannic acid.

[0081] 2. Preparation of coated iron powder

[0082] (2.1) 1.0 g of the modified tannic acid described above was dissolved in 30 mL of isopropyl alcohol, 0.04 g of PVP K30 powder (4% of the mass of the modified tannic acid) was added, and ultrasonic treatment (30 kHz, 300 W) was performed for 20 min to fully dissolve and disperse it.

[0083] (2.2) 5 g of nano-iron powder (particle size 50 nm, mass ratio of modified tannic acid to iron powder 1:5) was added, ultrasonic treatment and stirring were continued for 30 min, and the solvent was removed by distillation under reduced pressure to obtain coated iron powder.

[0084] 3. Preparation of adhesive

[0085] (3.1) A component: bisphenol A type epoxy resin 100 g, carboxyl-terminated liquid nitrile rubber 12 g, fumed silica 2 g, KH560 1 g, BYK-111 0.3 g, BYK-088 0.3 g were sequentially added and stirred uniformly to obtain the A component, which was ready for packaging.

[0086] (3.2) B component: 90 g of modified alicyclic amine curing agent (Riche R-2026) was taken, 5 g of coated iron powder obtained in step (3), 2 g of organic bentonite (ZT-S), 0.3 g of BYK-111, and 0.3 g of BYK-088 were added, and stirred uniformly to obtain the B component, which was ready for packaging.

[0087] Comparative Example 1

[0088] Compared with Example 1, the difference is that the B component does not contain coated iron powder.

[0089] Comparative Example 2

[0090] Compared with Example 1, the difference is that step 1 is not included, and in step 2, the modified tannic acid is replaced with an equal amount of unmodified tannic acid.

[0091] Test Example

[0092] The Q235 steel plate with uniform rust layer (the rust layer thickness is about 60 μm) was selected, and a double lap joint sample was prepared according to GB / T 7124-2008 standard. The adhesive was mixed uniformly according to the mass ratio of A component to B component 100:65, and was uniformly coated on the lap joint area, the adhesive layer thickness was about 2 mm, after being attached and compressed, a flat electromagnetic iron was applied on the outside of the sample, the magnetic induction intensity was 0.2 T and was applied vertically to the surface of the steel plate, and the magnetic field was applied for 30 min. After the magnetic field was removed, the sample was cured at room temperature for 24 h. After curing, the shear strength performance was tested by using a universal material testing machine.

[0093] The control group: the Q235 steel plate with mechanical polishing treatment and no rust on the surface was used as the bonding substrate, and a double lap joint sample was prepared according to GB / T 7124-2008 standard. The adhesive was the adhesive of Comparative Example 1, and A component and B component were mixed uniformly according to the mass ratio 100:65, and were uniformly coated on the lap joint area, the adhesive layer thickness was about 2 mm, after being attached and compressed, the sample was cured at room temperature for 24 h without applying an external magnetic field. After curing, the shear strength was tested by using a universal material testing machine.

[0094] The shear strength of each example and comparative example is shown in Table 1:

[0095] Table 1

[0096] Group Shear strength / MPa Example 1 21.5 Example 2 20.8 Comparative Example 1 8.2 Comparative Example 2 14.1 Control 22.4

[0097] From the above results, it can be seen that the adhesives of Example 1 and Example 2 can still achieve high-strength bonding effect on the surface of the Q235 steel plate without polishing and rust removal, and the shear strength is close to that of the control group after thorough rust removal treatment. This shows that the modified tannin acid coated iron powder used in the application can be effectively enriched at the rust interface under the induction of a magnetic field, and through the synergistic effect of in-situ rust conversion complexation reaction and amine-epoxy crosslinking reaction, a dense and firm interface layer is formed, thereby significantly improving the bonding performance.

[0098] Comparative Example 1 does not contain rust conversion agent and magnetic response filler, and only uses ordinary epoxy resin to directly bond the rusted steel plate. Since the interface cannot effectively remove or passivate the rust layer, the shear strength is greatly reduced only by relying on the physical adhesion of the resin itself.

[0099] Comparative Example 2 uses tannin acid coated iron powder, which can react with iron rust, but lacks active amine groups to react with the epoxy system, and cannot form a crosslinking network at the interface, so the interface bonding strength is significantly reduced.

[0100] The above describes the application in detail in combination with examples, but the application is not limited to the above examples, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the application.

Claims

1. A method for preparing an adhesive, comprising component A and component B, characterized in that: The preparation method comprises the following steps: S1, reacting tannic acid with chloroacetyl chloride, while controlling the amount of tannic acid to be excessive, to obtain chloroacetylated tannic acid; S2, reacting chloroacetylated tannic acid with triethylenetetramine to obtain modified tannic acid; S3, dissolving the modified tannic acid in alcohol, adding a dispersant and nano iron powder, stirring, and removing the solvent by reduced pressure distillation to obtain coated iron powder; S4. Mixing the coated iron powder with the raw materials including a first thixotropic agent and an amine curing agent to obtain the B component; mixing the raw materials including bisphenol A epoxy resin, a second thixotropic agent, a toughening agent, and a coupling agent to obtain the A component.

2. The preparation method according to claim 1, characterized in that In step S1, the molar ratio of tannic acid to chloroacetyl chloride is 1:3-6; and / or the reaction is carried out in the presence of a solvent and a catalyst; and / or the reaction temperature is 0-25° C., and the reaction time is 6-12 hours; and / or the reaction is carried out under an inert atmosphere.

3. The preparation method according to claim 2, characterized in that In step S1, the reaction includes: first mixing tannic acid, a solvent and a catalyst, adding chloroacetyl chloride dropwise at 0-5°C, and after the addition is completed, heating to 10-25°C and reacting for 6-12 hours; and / or, the solvent of the reaction is selected from a mixed solvent of DMF and DCM, wherein the volume ratio of DMF to DCM is 1-2:1; and / or, the catalyst of the reaction is selected from triethylamine; and / or, the amount of the catalyst used in the reaction is 1-1.2 times the molar amount of chloroacetyl chloride.

4. The preparation method according to claim 1, characterized in that In step S2, the molar ratio of chloroacetyl to triethylenetetramine in the chloroacetylated tannic acid is 1:1.5-2; and / or the reaction is carried out in the presence of a solvent and a catalyst; and / or the reaction temperature is 50-70° C., and the reaction time is 6-12 h; and / or the reaction is carried out under an inert atmosphere.

5. The preparation method according to claim 4, characterized in that In step S2, the solvent of the reaction is selected from DMF or DMSO; and / or the catalyst of the reaction is selected from triethylamine or potassium carbonate; and / or the amount of the catalyst used in the reaction is 1 to 1.2 times the molar amount of chloroacetyl groups in the chloroacetylated tannic acid.

6. The preparation method according to claim 1, characterized in that In step S3, the alcohol is ethanol or isopropanol; and / or the mass volume ratio of the modified tannic acid to the alcohol is 1g / 20-50mL; and / or the dispersant is at least one of PVP, polyvinyl alcohol, and sodium dodecylbenzenesulfonate; and / or the amount of the dispersant is 2%-10% of the mass of the modified tannic acid; and / or the particle size of the nano iron powder is 20-80nm; and / or the mass ratio of the modified tannic acid to the nano iron powder is 1:4-10; and / or ultrasonic treatment is performed during the stirring process, the ultrasonic treatment time is 0.5-1h, and the stirring time is 0.5-1h.

7. The preparation method according to claim 1, characterized in that In step S4, the amine curing agent is selected from at least one of modified alicyclic amines and modified polyether amines; and / or the toughening agent is selected from carboxyl-terminated liquid nitrile rubber; and / or the first thixotropic agent and the second thixotropic agent are independently selected from at least one of organic bentonite and fumed silica; and / or the coupling agent is selected from at least one of KH550 and KH560.

8. The preparation method according to claim 1, characterized in that In parts by mass, the B component comprises: 85-90 parts of amine curing agent and 5-10 parts of coated iron powder; Calculated by mass, the component A includes: 100 parts of bisphenol A epoxy resin, 10-15 parts of toughening agent, 1-3 parts of thixotropic agent, and 0.5-1.5 parts of coupling agent; The mass ratio of component A to component B is 100:60 to 100:70; Optionally, the component A and the component B further include a dispersant and a defoaming agent.

9. An adhesive, characterized in that: The method is as described in any one of claims 1 to 8.

10. Use of the adhesive as claimed in claim 9 in bonding iron-based materials.