Structural bonding adhesive capable of being cured at room temperature to realize rapid positioning and preparation method thereof

Abstract

The invention discloses a structural bonding adhesive capable of being cured at room temperature to realize rapid positioning and a preparation method of the structural bonding adhesive. The structural bonding adhesive comprises a component A and a component B, the component A comprises polyhydroxy benzaldehyde, a first filler and a first thixotropic agent; the component B comprises a curing agent, an accelerant, a second filler and a second thixotropic agent; the polyhydroxy benzaldehyde is an aromatic compound of which the benzene ring contains at least one aldehyde group and two hydroxyl groups; the curing agent is a polythiol curing agent; the accelerator comprises a Lewis acid. The invention provides a novel phenolic aldehyde-thiol curing system, through the matching use of all the components, the surface drying can be realized within 15 minutes, the excellent bonding strength can be realized within 2 hours, and the requirement on quick positioning in the construction process in practical application can be met; the adhesive for structural bonding has excellent bonding capacity on most of base materials such as metal, ceramic and plastic.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to an adhesive for structural bonding that can be cured at room temperature to achieve rapid positioning, and a preparation method thereof. Background Art

[0002] Epoxy adhesives have excellent mechanical properties, bonding properties, good insulation and dielectric resistance, small shrinkage, good stability and good process performance, and play an increasingly important role in the industrial field. The automated operation of the power battery assembly plant assembly line requires that the epoxy adhesive cures quickly or quickly reaches the positioning strength. Use fast positioning glue to plug holes in the rear of the car body, door sills, chassis, door components, front and rear ends, decorative pillars, instrument panels, engine compartments and other parts. Room temperature fast curing epoxy adhesives mainly use highly active resins, fast curing agents and high-efficiency accelerators. Compared with amines, anhydrides and other curing agents, thiol curing agents have the characteristics of low-temperature fast curing. They are widely used in the field of adhesives and can be quickly cured with epoxy resin at room temperature. They can be cured within more than ten minutes and are suitable for positioning, assembly, repair, sealing, potting and other applications. It can improve efficiency, reduce pollution, and improve product quality and stability, so it has received widespread attention. Pentaerythritol tetrakis (3-mercaptopropionic acid) ester is the most commonly used commercial thiol curing agent. It can be directly compounded with an accelerator to react with epoxy resin at room temperature. However, it has the following disadvantages:

[0003] First, the curing agent has a low viscosity and is very easy to flow during operation, causing inconvenience in construction and other aspects;

[0004] Second, the adhesive obtained after the curing agent and epoxy resin are cured has low bonding strength, which is insufficient to meet the needs of certain fields.

[0005] In order to adapt epoxy adhesive to the application in different scenarios, the methods commonly used to improve the curing speed and bonding strength of epoxy adhesive are: first, modify the mercaptan curing agent. For example, patent CN118185532B discloses a high bonding strength epoxy adhesive that cures quickly at room temperature and a preparation method thereof. The high bonding strength epoxy adhesive that cures quickly at room temperature includes component A: 85-95 parts of epoxy resin, 5-6 parts of diluent, 10-12 parts of toughening agent, 60-70 parts of filler, 1-5 parts of thixotropic agent, 1-10 parts of coupling agent, 0.5-3 parts of defoaming agent, and 0.1-1 parts of colorant; component B: 90-100 parts of polyester modified β-hydroxy mercaptan, 1.5-2.5 parts of accelerator, 60-70 parts of filler, 1-5 parts of thixotropic agent, 1-10 parts of coupling agent, and 0.5-3 parts of defoaming agent. The polyester modified β-hydroxythiol is prepared from trimethylolpropane, ε-caprolactone, epichlorohydrin and sodium hydrosulfide. The modification of the thiol increases the surface drying time and the bonding strength and improves the positioning performance. Second, increase the active components to improve the final performance of epoxy resin. For example, patent CN103305130A discloses a fast positioning structural adhesive, which includes component A and component B. Component A includes: 20-50 parts of epoxy resin, 5-52 parts of (methyl) acrylate monomer, 5-20 parts of elastomer, 0.5-5 parts of peroxide free radical initiator, 0.01-1 parts of free radical inhibitor, 0.01-0.5 parts of metal ion complexing agent, 0.1-2 parts of auxiliary agent; component B includes: 5-50 parts of epoxy resin room temperature curing agent, 1-5 parts of epoxy resin curing accelerator, 5-52 parts of (methyl) acrylate monomer, 5-20 parts of elastomer, 0.1-5.0 parts of reducing agent, 0.001-0.5 parts of accelerator, and 0.1-2 parts of auxiliary agent. This invention overcomes the shortcomings of long positioning time and full curing time by adding light-curing components.

[0006] Although it has always occupied an important position in room temperature fast-curing epoxy adhesives, the demand for industrial scenarios is constantly expanding. In order to provide more solutions and provide fast-positioning application scenarios, the development of a new curing system is also an urgent need for the development of modern industry and is of great significance to the adhesive industry. Summary of the invention

[0007] To solve the above problems, the first object of the present invention is to provide a structural bonding adhesive that can be cured at room temperature to achieve rapid positioning. The structural adhesive has developed a new phenolic-thiol curing system that can quickly gel at room temperature and reach initial strength in a short time, which can meet the demand for rapid positioning during the construction process in practical applications.

[0008] The second object of the present invention is to provide a method for preparing a structural bonding adhesive that can be cured at room temperature to achieve rapid positioning.

[0009] Specifically, the following technical solutions are provided:

[0010] The first aspect of the present invention provides a structural bonding adhesive that can be cured at room temperature to achieve rapid positioning, comprising component A and component B; characterized in that component A comprises polyhydroxybenzaldehyde, a first filler, and a first thixotropic agent; component B comprises a curing agent, an accelerator, a second filler, and a second thixotropic agent;

[0011] The polyhydroxybenzaldehyde is an aromatic compound containing at least one aldehyde group and two hydroxyl groups on the benzene ring;

[0012] The curing agent is a polythiol curing agent;

[0013] The accelerator comprises a Lewis acid.

[0014] Furthermore, the structural bonding adhesive that can be cured at room temperature to achieve rapid positioning, in terms of weight percentage, the component A comprises 90 to 100 parts of polyhydroxybenzaldehyde, 18 to 22 parts of a first filler, and 1.8 to 2.2 parts of a first thixotropic agent; the component B comprises 90 to 110 parts of a curing agent, 0.2 to 0.4 parts of an accelerator, 18 to 22 parts of a second filler, and 1.8 to 2.2 parts of a second thixotropic agent.

[0015] Furthermore, the polyhydroxybenzaldehyde comprises one or more of 2,3-dihydroxybenzaldehyde, 3,4-dihydroxy-5-methoxybenzaldehyde and 3,4-dihydroxybenzaldehyde.

[0016] Furthermore, the promoter comprises one or more of trifluoroacetic acid, zirconium tetrachloride and zinc dichloride.

[0017] Furthermore, the curing agent comprises one or more of pentaerythritol tetrakis mercaptoacetate, pentaerythritol tetrakis (3-mercaptopropionate) and pentaerythritol tetrakis (3-mercaptobutyrate).

[0018] Furthermore, the structural bonding adhesive that can be cured at room temperature to achieve rapid positioning, wherein component A also contains a first coupling agent, a first defoamer and an auxiliary agent, and contains 0.27 to 1 parts of the first coupling agent, 0.4 to 1 parts of the first defoamer and 0.4 to 1 parts of the auxiliary agent by mass; component B also contains a second coupling agent and a second defoamer, and contains 0.27 to 1 parts of the second coupling agent and 0.4 to 1 parts of the second defoamer by mass.

[0019] Furthermore, the first coupling agent and the second coupling agent are respectively selected from one or more of γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-mercaptopropyltriethoxysilane.

[0020] Furthermore, the auxiliary agent is selected from one or more of a dehydrating agent, a flame retardant, a diluent, a pigment, an antioxidant, a leveling agent, a leveling agent, and an ion capture agent.

[0021] Furthermore, the first thixotropic agent and the second thixotropic agent are respectively selected from a combination of one or more of modified castor oil, organic bentonite, polyamide wax, and fumed silica.

[0022] Furthermore, the first defoamer and the second defoamer are respectively selected from a combination of one or more of an organosilicon defoamer, a polyether defoamer, and a mineral oil defoamer.

[0023] On the other hand, the present invention also provides a method for preparing a structural bonding adhesive that can be cured at room temperature to achieve rapid positioning, and the preparation method is as follows:

[0024] (1) Preparation of component A: polyhydroxybenzaldehyde, a first filler, a first thixotropic agent, a first coupling agent, a first defoaming agent and an auxiliary agent are added to a stirring kettle according to a weight ratio, the rotation speed is set in the range of 200 to 400 rpm, and vacuum stirring is performed until the mixture is completely dispersed and uniformly dispersed. The temperature is controlled at 30° C. to 50° C. and stirring is performed for 30 to 50 minutes. The stirred glue solution is placed in a planetary homogenizer for mixing and degassing. After degassing, component A can be obtained.

[0025] (2) Preparation of component B: Add the curing agent, accelerator, second filler, second thixotropic agent, second coupling agent and second defoaming agent into a stirring kettle according to weight ratio, set the rotation speed in the range of 200 to 400 rpm, stir until completely dispersed, control the temperature at 30°C to 50°C, and stir for 30 to 50 minutes; place the stirred glue solution in a planetary homogenizer for mixing and degassing. After degassing, component B can be obtained.

[0026] (3) Component A and component B are uniformly mixed according to the mass ratio and cured at room temperature to obtain a structural bonding adhesive.

[0027] Furthermore, the mixing mass ratio of component A to component B is 100:(160-200).

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The structural bonding adhesive protected by the present invention can be quickly cured at room temperature. It is a two-component phenolic-thiol curing system. Through the combination of the components, the surface can be dry within 5 minutes and excellent bonding strength can be achieved within 2 hours. Compared with the common two-component epoxy structural adhesive on the market, it has a faster curing speed at room temperature and a shorter curing time, which can improve construction efficiency. There is no need to increase the curing speed by heating, which avoids the reduction of the viscosity of the adhesive and the flow of the adhesive.

[0030] (2) The common two-component epoxy structural adhesive on the market has a low bonding strength, which generally does not exceed 20MPa when cured at room temperature. The strength can be greater than 20MPa after heating, but heating will cause problems such as reduced viscosity. The two-component structural adhesive of the present invention can reach a bonding strength of more than 30MPa after curing at room temperature for 2 hours. In addition, since polyhydroxybenzaldehyde has a structure similar to catechol and contains multiple active ortho-phenolic hydroxyl groups, it can react with the surface of most substrates to produce a stronger bonding force through hydrogen bonding. The structural bonding adhesive has excellent bonding ability to most substrates such as metals, ceramics and plastics.

[0031] (3) The structural bonding adhesive protected by the present invention uses polyhydroxybenzaldehyde as the main resin and polythiol as the main curing agent. The activation energy of the mercaptoaldehyde polycondensation reaction between polyhydroxybenzaldehyde and polythiol will be greatly reduced under the action of Lewis acid, which allows the structural bonding adhesive protected by the present invention to be quickly cured at room temperature, meeting the rapid positioning requirements in specific fields. In addition, the high rigidity of the benzene ring of polyhydroxybenzaldehyde and the flexibility of the long carbon chain of polythiol enable the structural adhesive to achieve a good balance between rigidity and flexibility, thereby having high bonding strength. DETAILED DESCRIPTION

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0034] The sources of some of the raw materials used in the following examples and comparative examples are as follows:

[0035] Bisphenol A epoxy resin, brand name jER-828, from Mitsubishi Chemical of Japan; 2,3-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, analytical grade, from Macklin; curing agent: pentaerythritol tetrakis (3-mercaptopropionic acid) ester, brand name PETMP, from Bruno Bock of Germany; accelerator: trifluoroacetic acid, brand name CF 3 COOH, zirconium tetrachloride, brand name ZrCl 4 , zinc dichloride, brand name ZnCl 2, analytical grade, from Macklin; 2,4,6-tris(dimethylaminomethyl)phenol, brand name DMP-30, from Evonik, Germany; imidazole adduct, brand name PN-23, from Ajinomoto, Japan; filler: spherical silica powder, brand name FB-5D, from DENKA, Japan; thixotropic agent: fumed silica, brand name R-202, from Evonik, Germany; coupling agent: γ-glycidyloxypropyl, brand name KH-560, γ-mercaptopropyltriethoxysilane, brand name KH-580, from Nanjing Shuguang Chemical; defoaming agent: brand names BYK-070 and BYK-088, from BYK Chemical; colorant: carbon black, brand name MA-220, from Mitsubishi Chemical, Japan.

[0036] Example 1

[0037] Preparation of structural bonding adhesive that can be cured at room temperature to achieve rapid positioning:

[0038] (1) Preparation of component A: First, 100 parts of 2,3-dihydroxybenzaldehyde, 20 parts of spherical silica, 2 parts of fumed silica, 0.3 parts of γ-glycidyloxypropyltrimethoxysilane, 0.5 parts of defoamer BYK-070 and 0.3 parts of carbon black were added to a stirring kettle at a speed of 300 rpm, a temperature of 40° C., a vacuum degree of 0.07 MPa, and stirred for 40 minutes. The mixture was cooled to room temperature to obtain component A.

[0039] (2) Preparation of component B: First, 100 parts of pentaerythritol tetrakis (3-mercaptopropionate), 0.3 parts of trifluoroacetic acid, 20 parts of spherical silica, 2 parts of fumed silica, 0.3 parts of γ-mercaptopropyl triethoxysilane, and 0.5 parts of defoamer BYK-088 were added to a stirring kettle at a speed of 300 rpm, a temperature of 40° C., a vacuum degree of 0.07 MPa, and stirring for 40 minutes. The mixture was cooled to room temperature to obtain component B.

[0040] (3) Component A and component B are uniformly mixed in a mass ratio of 100:180 and cured at room temperature to obtain a structural bonding adhesive.

[0041] Example 2

[0042] A structural bonding adhesive that can be cured at room temperature and can achieve rapid positioning is prepared according to the method of Example 1, except that: (1) 90 parts of 2,3-dihydroxybenzaldehyde and 18 parts of spherical silica are added; and (2) 90 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.27 parts of trifluoroacetic acid are added. The remaining conditions are the same as those of Example 1, and a structural bonding adhesive that can be cured at room temperature and can achieve rapid positioning is obtained.

[0043] Example 3

[0044] A structural bonding adhesive that can be cured at room temperature and can achieve rapid positioning was prepared according to the method of Example 1, except that (1) 110 parts of 2,3-dihydroxybenzaldehyde and 22 parts of spherical silica were added; and (2) 110 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.33 parts of trifluoroacetic acid were added. The remaining conditions were the same as those of Example 1, and a structural bonding adhesive that can be cured at room temperature and can achieve rapid positioning was obtained.

[0045] Example 4

[0046] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 1, except that 100 parts of 3,4-dihydroxybenzaldehyde were added; the remaining conditions were the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0047] Example 5

[0048] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 2, except that 90 parts of 3,4-dihydroxybenzaldehyde was added; the remaining conditions were the same as in Example 2, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0049] Example 6

[0050] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 3, except that 110 parts of 3,4-dihydroxybenzaldehyde were added; the remaining conditions were the same as in Example 3, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0051] Example 7

[0052] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is prepared according to the method of Example 1, except that component A and component B are uniformly mixed at a mass ratio of 100:160; the remaining conditions are the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is obtained.

[0053] Example 8

[0054] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is prepared according to the method of Example 1, except that component A and component B are uniformly mixed at a mass ratio of 100:200; the remaining conditions are the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is obtained.

[0055] Example 9

[0056] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 1, except that 0.20 parts of trifluoroacetic acid was added; the remaining conditions were the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0057] Example 10

[0058] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 1, except that 0.40 parts of trifluoroacetic acid was added; the remaining conditions were the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0059] Embodiment 11

[0060] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 1, except that 0.30 parts of zirconium tetrachloride was added; the remaining conditions were the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0061] Example 12

[0062] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was prepared according to the method of Example 1, except that 0.30 parts of zinc dichloride was added; the remaining conditions were the same as in Example 1, and a structural bonding adhesive that can be cured at room temperature and achieve rapid positioning was obtained.

[0063] Comparative Example 1

[0064] An epoxy adhesive was prepared according to the method of Example 1, except that (1) 100 parts of epoxy resin was added and (2) 0.3 parts of 2,4,6-tris(dimethylaminomethyl)phenol was added. The remaining conditions were the same as those of Example 1 to obtain an epoxy adhesive.

[0065] Comparative Example 2

[0066] An epoxy adhesive was prepared according to the method of Example 1, except that (1) 100 parts of epoxy resin were added and (2) 1 part of imidazole adduct was added. The remaining conditions were the same as those of Example 1 to obtain an epoxy adhesive.

[0067] Comparative Example 3

[0068] An epoxy adhesive was prepared according to the method of Comparative Example 3, except that the epoxy adhesive was cured at 80° C. for 2 h to obtain the epoxy adhesive.

[0069] Comparative Example 4

[0070] An adhesive for structural bonding was prepared according to the method of Example 1, except that (1) 85 parts of 2,3-dihydroxybenzaldehyde and 17 parts of spherical silica were added; and (2) 85 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.26 parts of trifluoroacetic acid were added. The remaining conditions were the same as those of Example 1 to obtain an adhesive for structural bonding.

[0071] Comparative Example 5

[0072] An adhesive for structural bonding was prepared according to the method of Example 1, except that (1) 115 parts of 2,3-dihydroxybenzaldehyde and 23 parts of spherical silica were added; and (2) 115 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.35 parts of trifluoroacetic acid were added. The remaining conditions were the same as those of Example 1 to obtain an adhesive for structural bonding.

[0073] Comparative Example 6

[0074] An adhesive for structural bonding was prepared according to the method of Example 1, except that (1) 85 parts of 3,4-dihydroxybenzaldehyde and 17 parts of spherical silica were added; and (2) 85 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.26 parts of trifluoroacetic acid were added. The remaining conditions were the same as those of Example 1 to obtain an adhesive for structural bonding.

[0075] Comparative Example 7

[0076] An adhesive for structural bonding was prepared according to the method of Example 1, except that (1) 115 parts of 3,4-dihydroxybenzaldehyde and 23 parts of spherical silica were added; and (2) 115 parts of pentaerythritol tetrakis(3-mercaptopropionate) and 0.35 parts of trifluoroacetic acid were added. The remaining conditions were the same as those of Example 1 to obtain an adhesive for structural bonding.

[0077] Comparative Example 8

[0078] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is prepared according to the method of Example 1, except that component A and component B are uniformly mixed at a mass ratio of 100:150; the remaining conditions are the same as in Example 1, to obtain a structural bonding adhesive.

[0079] Comparative Example 9

[0080] A structural bonding adhesive that can be cured at room temperature and achieve rapid positioning is prepared according to the method of Example 1, except that component A and component B are uniformly mixed at a mass ratio of 100:210; the remaining conditions are the same as in Example 1, to obtain a structural bonding adhesive.

[0081] Comparative Example 10

[0082] An adhesive for structural bonding was prepared according to the method of Example 1, except that 0.10 parts of trifluoroacetic acid was added; the other conditions were the same as in Example 1, to obtain an adhesive for structural bonding.

[0083] Comparative Example 11

[0084] An adhesive for structural bonding was prepared according to the method of Example 1, except that 0.50 parts of trifluoroacetic acid was added; the other conditions were the same as in Example 1, to obtain an adhesive for structural bonding.

[0085] Performance Testing

[0086] The performance tests of the resin compositions prepared in the above examples and comparative examples are as follows:

[0087] Dry time

[0088] (1) Sample preparation: After mixing components A and B evenly according to the mass ratio, pour them into the corresponding mold to obtain the surface drying time test sample.

[0089] (2) Test process: Wipe the tip of your finger with anhydrous ethanol and gently touch three different parts of the sample surface. Repeat the above operation at appropriate intervals until no sample adheres to the finger. Record the time from the completion of sample preparation to the time when the sample no longer adheres to the finger, which is the surface drying time of the sample.

[0090] Bonding strength

[0091] (1) Sample preparation: Mix components A and B at a ratio of 1:1, extrude them onto an iron sheet, and then press another iron sheet onto it. Curing at room temperature for 2 hours will yield a bonding test sample. When preparing the sample, align the two iron sheets as accurately as possible and make the thickness of the adhesive layer as uniform and consistent as possible.

[0092] (2) Test process: Clamp the sample symmetrically on the fixture, with the distance between the clamp and the nearest bonding end being 50 mm. When clamping, there is no relative movement between the fixture and the sample, and the long axis of the sample is kept consistent with the direction of force and the center line of the fixture. The tensile rate during the test is 5 mm / min. In order to ensure the accuracy of the test results, the number of samples is not less than 3, and the average value is taken as the final result.

[0093] The above test results are shown in Table 1 below:

[0094] Table 1

[0095]

[0096]

[0097] As can be seen from Table 1, in the commercially available epoxy resin and thiol system in Comparative Example 1, when the accelerator 2,4,6-tris(dimethylaminomethyl)phenol is used, the surface drying time is 31 minutes and the bonding strength is 8.9 MPa; in Comparative Example 2, the accelerator imidazole adduct is used instead, and the surface drying time is greater than 24 hours; it can be seen from Comparative Examples 1 and 2 that the ordinary commercially available epoxy resin and thiol system is difficult to meet the requirements of structural bonding when cured at room temperature; and compared with Comparative Example 2, Comparative Example 3 also takes 26 minutes to dry after heating at 80°C for 2 hours, and the bonding strength is 23.6 MPa.

[0098] As can be seen from Examples 1-6, the room temperature curable structural bonding adhesive prepared by the present invention can achieve rapid positioning, after reasonable matching of different components, can be cured at room temperature, can be dry within 15 minutes, and can have excellent bonding strength within 2 hours. It is better than the surface drying time and initial bonding strength in the commercially available epoxy resin and thiol system, meets the requirements of rapid positioning structural bonding, can greatly reduce construction time, and improve efficiency. By comparing Comparative Examples 4-7, it can be seen that when polyhydroxybenzaldehyde and curing agent exceed the range of parts, the surface drying time will be extended and the curing speed will be slowed down; the bonding strength is less than 30MPa, and the performance is reduced compared to Examples 1-6.

[0099] It can be seen from Example 4, Example 7 and Example 8 that when the mixing ratio of component A and component B is 100:(160-200), the aldehyde group and the thiol group are just completely reacted or slightly excessive, and the surface drying time is short and the bonding strength is high. It can be seen from Comparative Examples 8 and 9 that when the ratio is 100:150 and 100:210, the aldehyde group or the thiol group is seriously excessive, and there are a large number of aldehyde groups or thiol groups inside that are not completely reacted, resulting in a slow curing speed and a decrease in bonding strength.

[0100] It can be seen from Examples 4, 9 and 10 that when the amount of initiator is 0.2 to 0.4 parts, the surface drying time is short and the bonding strength is high. It can be seen from Comparative Example 10 that when the amount of accelerator is too low, the curing speed is slow and the surface drying time is long; it can be seen from Comparative Example 11 that when the amount of accelerator is too high, the curing speed is too fast, the heat is concentrated in a short time, and the internal stress of the cured product is too large, resulting in a sharp decrease in bonding strength. It can be seen from Examples 11 and 12 that when the accelerator is replaced by zirconium tetrachloride and zinc dichloride from trifluoroacetic acid, the performance in Examples 1-6 can still be maintained.

[0101] The above-described embodiments are only preferred examples for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A structural bonding adhesive that can be cured at room temperature to achieve rapid positioning, comprising component A and component B; characterized in that: The component A comprises polyhydroxybenzaldehyde, a first filler, and a first thixotropic agent; the component B comprises a curing agent, an accelerator, a second filler, and a second thixotropic agent; The polyhydroxybenzaldehyde is an aromatic compound containing at least one aldehyde group and two hydroxyl groups on the benzene ring; The curing agent is a polythiol curing agent; The accelerator comprises a Lewis acid.

2. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 1, characterized in that: In parts by mass, the component A comprises 90 to 100 parts of polyhydroxybenzaldehyde, 18 to 22 parts of a first filler, and 1.8 to 2.2 parts of a first thixotropic agent; the component B comprises 90 to 110 parts of a curing agent, 0.2 to 0.4 parts of an accelerator, 18 to 22 parts of a second filler, and 1.8 to 2.2 parts of a second thixotropic agent.

3. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 1, characterized in that: The polyhydroxybenzaldehyde comprises one or more of 2,3-dihydroxybenzaldehyde, 3,4-dihydroxy-5-methoxybenzaldehyde and 3,4-dihydroxybenzaldehyde.

4. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 1, characterized in that: The promoter comprises one or more of trifluoroacetic acid, zirconium tetrachloride and zinc dichloride.

5. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 1, characterized in that: The curing agent includes one or more of pentaerythritol tetrakis mercaptoacetate, pentaerythritol tetrakis (3-mercaptopropionate) and pentaerythritol tetrakis (3-mercaptobutyrate).

6. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 1, characterized in that: Component A further comprises a first coupling agent, a first defoaming agent and an auxiliary agent, and in parts by mass, comprises 0.27 to 1 parts of the first coupling agent, 0.4 to 1 parts of the first defoaming agent and 0.4 to 1 parts of the auxiliary agent; component B further comprises a second coupling agent and a second defoaming agent, and in parts by mass, comprises 0.27 to 1 parts of the second coupling agent and 0.4 to 1 parts of the second defoaming agent.

7. The structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 6, characterized in that: The first coupling agent and the second coupling agent are respectively selected from one or more of γ-glycidyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-mercaptopropyltriethoxysilane.

8. The room temperature curable structural bonding adhesive capable of realizing rapid positioning according to claim 6, characterized in that: The auxiliary agent is selected from one or more of a dehydrating agent, a flame retardant, a diluent, a pigment, an antioxidant, a leveling agent, a leveling agent, and an ion capture agent.

9. A method for preparing a structural bonding adhesive that can be cured at room temperature and can achieve rapid positioning according to any one of claims 1 to 8, characterized in that: (1) Preparation of component A: polyhydroxybenzaldehyde, the first filler, the first thixotropic agent, the first coupling agent, the first defoaming agent and the auxiliary agent are added to a stirring kettle according to the weight ratio, and vacuum stirred until they are completely dispersed; the stirred glue solution is placed in a planetary homogenizer for mixing and degassing. After the degassing is completed, component A can be obtained. (2) Preparation of component B: Add the curing agent, accelerator, second filler, second thixotropic agent, second coupling agent and second defoaming agent into a stirring kettle according to weight ratio, and stir until they are completely dispersed; place the stirred glue solution in a planetary homogenizer for mixing and degassing. After degassing, component B can be obtained. (3) Component A and component B are uniformly mixed according to the mass ratio and cured at room temperature to obtain a structural bonding adhesive.

10. The method for preparing the structural bonding adhesive capable of curing at room temperature and realizing rapid positioning according to claim 9, characterized in that: The mixing mass ratio of component A to component B is 100:(160-200).

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