A shock-absorbing expansion adhesive, its preparation method and application

Abstract

This application relates to a shock-absorbing expansion adhesive, its preparation method, and its application, belonging to the technical field of shock-absorbing expansion adhesives. The components of the shock-absorbing expansion adhesive include: epoxy-based POSS: 1-2 wt%, terminal epoxy-based polybutadiene liquid rubber: 3.5-4.5 wt%, organically modified montmorillonite: 0.1-0.3 wt%, rubber: 20-25 wt%, epoxy resin: 5.5-6.5 wt%, dicyandiamide: 0.3-0.5 wt%, dicumyl peroxide: 0.3-0.5 wt%, zinc oxide: 0.3-0.5 wt%, foaming agent: 0.15-0.4 wt%, dioctyl phthalate: 20-25 wt%, and calcium carbonate: 38-45 wt%. This shock-absorbing expansion adhesive exhibits excellent resistance to damp heat, effectively solving the technical problem of insufficient damp heat resistance in current shock-absorbing expansion adhesives. This application also provides a preparation method and application of the shock-absorbing expansion adhesive.

Description

Technical Field

[0001] This application relates to the field of shock-absorbing expansion adhesive technology, and in particular to a shock-absorbing expansion adhesive, its preparation method, and its application. Background Technology

[0002] Shock-absorbing expansion adhesive is the most widely used adhesive in automotive welding processes. It is used in the gaps between automotive inner and outer panels and reinforcing ribs and other components to effectively reduce vibration and noise during vehicle operation, while improving the stability of inner and outer panels and the overall vehicle safety.

[0003] Currently, the initial adhesion of commercially available shock-absorbing expansion adhesives can meet the requirements of automotive welding processes. However, during the service of automobiles, they are inevitably subject to water and heat erosion, which can easily lead to problems such as failure of the shock-absorbing expansion adhesives. This problem is particularly prominent in environments with high humidity and high temperature, and may even result in adverse consequences such as parts falling off or injuries.

[0004] In summary, the damping expansion adhesive in the existing technology has insufficient resistance to damp heat. Summary of the Invention

[0005] This application provides a shock-absorbing expansion adhesive, its preparation method, and its application to solve the problem of insufficient resistance to damp heat in current shock-absorbing expansion adhesives.

[0006] In a first aspect, this application provides a shock-absorbing expanding adhesive, the components of which include: epoxy-based POSS: 1-2 wt%, terminal epoxy-based polybutadiene liquid rubber: 3.5-4.5 wt%, organically modified montmorillonite: 0.1-0.3 wt%, rubber: 20-25 wt%, epoxy resin: 5.5-6.5 wt%, dicyandiamide: 0.3-0.5 wt%, dicumyl peroxide: 0.3-0.5 wt%, zinc oxide: 0.3-0.5 wt%, foaming agent: 0.15-0.4 wt%, dioctyl phthalate: 20-25 wt%, and calcium carbonate: 38-45 wt%.

[0007] Optionally, the structure of the epoxy-based POSS is shown in Formula I:

[0008]

[0009] In Formula I, R1, R2, R3, R4, R5, R6, R7 and R8 may be the same or different, and each is independently selected from aliphatic chains containing epoxy groups.

[0010] Optionally, the aliphatic chain containing epoxy groups includes at least one of the following: 2,3-epoxypropoxypropyl, 3,4-epoxycyclohexylethyl.

[0011] Optionally, the end-capping structure of the epoxy-terminated polybutadiene liquid rubber includes at least one of the following: a single-terminated epoxy-terminated structure and a double-terminated epoxy-terminated structure.

[0012] Optionally, the organic modifier of the organically modified montmorillonite includes a silane coupling agent.

[0013] Optionally, the rubber includes styrene-butadiene rubber and cis-butadiene rubber.

[0014] Optionally, the weight ratio of the styrene-butadiene rubber to the butadiene rubber is 2:1.

[0015] Optionally, the epoxy resin includes at least one of the following: bisphenol A diglycidyl ether type epoxy resin and bisphenol F diglycidyl ether type epoxy resin.

[0016] Secondly, this application provides a method for preparing a shock-absorbing expansion adhesive, the method comprising:

[0017] Styrene-butadiene rubber, cis-butadiene rubber, and dioctyl phthalate were compounded to obtain a first mixture;

[0018] The epoxy group POSS, epoxy-terminated polybutadiene liquid rubber, organically modified montmorillonite, epoxy resin, dicyandiamide, dicumyl peroxide, zinc oxide, foaming agent, dioctyl phthalate 2, and calcium carbonate are first kneaded to obtain a second mixture.

[0019] The first mixture, the second mixture, and the third dioctyl phthalate were kneaded a second time, followed by vacuum degassing to obtain a shock-absorbing and expanding adhesive.

[0020] Thirdly, this application provides an application of a shock-absorbing expansion adhesive, which is used for bonding coated steel sheets to various components in the automotive field.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] The shock-absorbing expansion adhesive provided in this application introduces epoxy-based POSS. On the one hand, the organosilicon in its structure can enhance the heat resistance of the shock-absorbing expansion adhesive. On the other hand, its epoxy groups undergo a cross-linking reaction with the epoxy groups in epoxy resin and epoxy-terminated polybutadiene liquid rubber under the action of dicyandiamide, which can further promote the heat resistance of the shock-absorbing expansion adhesive. In addition, the epoxy-based POSS with large steric hindrance can also serve as the "gas nucleus" formation center of the foaming agent. Its synergistic effect with the foaming agent helps to hinder the transmission path of water vapor inside the shock-absorbing expansion adhesive, thereby improving the moisture resistance of the shock-absorbing expansion adhesive. Simultaneously, epoxy-terminated polybutadiene liquid rubber was introduced. On one hand, its epoxy groups undergo a cross-linking reaction with the epoxy groups of the epoxy resin under the action of dicyandiamide. On the other hand, its carbon backbone entangles with the carbon chain of the rubber to form physical cross-linking points, and forms chemical bonds during vulcanization. Therefore, it can significantly improve the compatibility among epoxy-terminated polybutadiene liquid rubber, rubber, and epoxy resin, which helps reduce microcracks or cracking caused by phase separation, thereby improving the damp heat resistance of the shock-absorbing expansion adhesive. In addition, organically modified montmorillonite was introduced. The interlayer voids in its structure can serve as "gas nuclei" formation centers for the foaming agent, which is conducive to the formation of a small and dense closed-cell structure by the foaming agent. This greatly reduces the possibility of bubble paralleling or collapse after foaming, thereby improving the moisture resistance of the shock-absorbing expansion adhesive. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A flowchart illustrating a method for preparing a shock-absorbing expansion adhesive provided in this application embodiment; Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Various embodiments of this application may exist in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it means including any referenced number (fraction or integer) within the indicated range. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared by existing methods.

[0028] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in this application, the terms "comprising," "including," etc., mean "including but not limited to." In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this application, "and / or" describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0029] This application provides a shock-absorbing expansion adhesive, the components of which include:

[0030] Epoxy POSS: 1-2 wt%, terminal epoxy polybutadiene liquid rubber: 3.5-4.5 wt%, organic modified montmorillonite: 0.1-0.3 wt%, rubber: 20-25 wt%, epoxy resin: 5.5-6.5 wt%, dicyandiamide: 0.3-0.5 wt%, dicumyl peroxide: 0.3-0.5 wt%, zinc oxide: 0.3-0.5 wt%, foaming agent: 0.15-0.4 wt%, dioctyl phthalate: 20-25 wt%, calcium carbonate: 38-45 wt%.

[0031] In some embodiments, the content of the epoxy group POSS is 1-2% by weight.

[0032] When the content of the epoxy group POSS is 1-2% by weight, the moisture and heat resistance of the shock-absorbing expansion adhesive can be improved. For example, the content of the epoxy group POSS can be 1% by weight, 1.1% by weight, 1.2% by weight, 1.3% by weight, 1.4% by weight, 1.5% by weight, 1.6% by weight, 1.7% by weight, 1.8% by weight, 1.9% by weight, or 2% by weight.

[0033] In some embodiments, the content of the terminal epoxy polybutadiene liquid rubber is 3.5-4.5% by weight.

[0034] When the content of the terminal epoxy-terminated polybutadiene liquid rubber is 3.5-4.5% by weight, it can improve the damp heat resistance of the shock-absorbing expansion adhesive. At lower contents, the compatibility of the components in the system is poor, easily leading to microcracks or cracking, thus reducing the damp heat resistance of the shock-absorbing expansion adhesive. At higher contents, the system undergoes excessive cross-linking, resulting in increased brittleness of the shock-absorbing expansion adhesive. For example, the content of the terminal epoxy-terminated polybutadiene liquid rubber can be 3.5% by weight, 3.6% by weight, 3.7% by weight, 3.8% by weight, 3.9% by weight, 4.0% by weight, 4.1% by weight, 4.2% by weight, 4.3% by weight, 4.4% by weight, or 4.5% by weight.

[0035] In some embodiments, the content of the organically modified montmorillonite is 0.1-0.3% by weight.

[0036] When the content of the organically modified montmorillonite is 0.1-0.3% by weight, it can synergistically promote the dimensional stability and moisture resistance of the shock-absorbing expanding adhesive with the foaming agent. For example, the content of the organically modified montmorillonite can be 0.1% by weight, 0.12% by weight, 0.14% by weight, 0.16% by weight, 0.18% by weight, 0.2% by weight, 0.22% by weight, 0.25% by weight, 0.28% by weight, 0.3% by weight, or other suitable contents.

[0037] In some embodiments, the rubber content is 20-25% by weight.

[0038] When the rubber content is 20-25% by weight, the toughness and heat resistance of the shock-absorbing expansion rubber can be appropriately increased. For example, the rubber content can be 20% by weight, 21% by weight, 22% by weight, 23% by weight, 24% by weight, or 25% by weight.

[0039] In some embodiments, the epoxy resin content is 5.5-6.5% by weight.

[0040] When the epoxy resin content is 5.5-6.5% by weight, the shock-absorbing expansion adhesive exhibits excellent adhesion and resistance to damp heat. When the content is <5.5% by weight, the system has fewer polar groups, resulting in poor adhesion of the shock-absorbing expansion adhesive, which is detrimental to practical applications. When the content is >6.5% by weight, the internal stress of the system increases, making it prone to microcracks, thereby reducing the damp heat resistance of the shock-absorbing expansion adhesive. For example, the epoxy resin content can be 5.5% by weight, 5.6% by weight, 5.7% by weight, 5.8% by weight, 5.9% by weight, 6.0% by weight, 6.1% by weight, 6.2% by weight, 6.3% by weight, 6.4% by weight, or 6.5% by weight.

[0041] In some embodiments, the dicyandiamide content is 0.3-0.5% by weight.

[0042] Dicyandiamide, as a catalytic curing agent, results in low cross-linking of the system when its content is <0.3 wt%, leading to reduced strength of the shock-absorbing expansion adhesive; when its content is >0.5 wt%, excessive cross-linking occurs, easily causing brittleness and increased internal stress in the shock-absorbing expansion adhesive, thereby generating microcracks and reducing its resistance to damp heat. For example, the dicyandiamide content can be 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%.

[0043] In some embodiments, the content of dicumyl peroxide is 0.3-0.5% by weight.

[0044] As a vulcanizing agent, dicumyl peroxide has several advantages. When its content is less than 0.3% by weight, it is difficult to achieve the desired vulcanization effect, leading to a decrease in the strength of the shock-absorbing expansion rubber. When its content is greater than 0.5% by weight, the system undergoes excessive cross-linking, which easily leads to increased brittleness of the shock-absorbing expansion rubber. For example, the content of dicumyl peroxide can be 0.30% by weight, 0.35% by weight, 0.40% by weight, 0.45% by weight, or 0.50% by weight.

[0045] In some embodiments, the zinc oxide content is 0.3-0.5% by weight.

[0046] Zinc oxide, as a vulcanization accelerator, is insufficient to achieve the desired accelerating effect when its content is <0.3% by weight, resulting in low vulcanization and reduced strength of the shock-absorbing expansion adhesive. Conversely, when its content is >0.5% by weight, excessive cross-linking occurs, increasing the brittleness of the shock-absorbing expansion adhesive. For example, the zinc oxide content can be 0.30% by weight, 0.35% by weight, 0.40% by weight, 0.45% by weight, or 0.50% by weight.

[0047] In some embodiments, the foaming agent content is 0.15-0.4% by weight.

[0048] When the content of the foaming agent is 0.15-0.4% by weight, it has a suitable foaming effect; when the content is <0.15% by weight, the N2 content inside the shock-absorbing expansion adhesive is low, making it difficult to counteract the cohesive force of the polymer, resulting in an insignificant foaming effect; when the content is >0.4% by weight, although the foaming ratio increases, defects such as collapse are prone to occur, thereby worsening the dimensional stability of the shock-absorbing expansion adhesive. For example, the content of the foaming agent can be 0.15% by weight, 0.20% by weight, 0.25% by weight, 0.30% by weight, 0.35% by weight, or 0.40% by weight.

[0049] In some embodiments, the content of dioctyl phthalate is 20-25% by weight.

[0050] When the content of dioctyl phthalate is 20-25% by weight, it has a suitable lubricating effect, which is beneficial for preparing shock-absorbing and expanding adhesives with moisture and heat resistance. If the content is too low, it is difficult to achieve the expected lubricating effect, which is not conducive to the preparation of shock-absorbing and expanding adhesives. If the content is too high, the proportion of polar groups in the system decreases, which can reduce the adhesion of the shock-absorbing and expanding adhesive. At the same time, the system's vulcanization effect deteriorates, and in severe cases, the system becomes difficult to cure, thereby reducing the strength of the shock-absorbing and expanding adhesive. For example, the content of dioctyl phthalate can be 20% by weight, 21% by weight, 22% by weight, 23% by weight, 24% by weight, or 25% by weight.

[0051] In some embodiments, the calcium carbonate content is 38-45% by weight.

[0052] Calcium carbonate, as a filler, when its content is 38-45% by weight, is beneficial for reducing production costs and increasing the dimensional stability, heat resistance, and other related properties of the shock-absorbing expansion adhesive. For example, the calcium carbonate content can be 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45% by weight, or other suitable contents.

[0053] In some embodiments, the epoxy group POSS has the structural formula shown in Formula I:

[0054]

[0055] In Formula I, R1, R2, R3, R4, R5, R6, R7 and R8 may be the same or different, and each is independently selected from aliphatic chains containing epoxy groups.

[0056] The organosilicon, epoxy groups, and large steric hindrance in the epoxy group POSS structure are beneficial to improving the damp heat resistance of the shock-absorbing expansion adhesive.

[0057] In some embodiments, the epoxy-containing aliphatic chain includes at least one of the following: 2,3-epoxypropoxypropyl, 3,4-epoxycyclohexylethyl.

[0058] In some embodiments, the end-capping structure of the epoxy-terminated polybutadiene liquid rubber includes at least one of the following: a single-terminated epoxy-terminated structure and a double-terminated epoxy-terminated structure.

[0059] The structural formula of epoxy-terminated polybutadiene liquid rubber is shown in Formula II:

[0060]

[0061] In Formula II, R9 is an adipose chain, R 10 It is an aliphatic chain containing epoxy groups or an aliphatic chain without epoxy groups.

[0062] The aforementioned epoxy-terminated polybutadiene liquid rubber can significantly improve its compatibility with rubber and epoxy resin, which helps reduce microcracks or cracking caused by phase separation, thereby improving the damp heat resistance of the shock-absorbing expansion adhesive. In addition, its epoxy groups are highly polar, which can promote the migration of the shock-absorbing expansion adhesive to the surface of the adhered object, thereby improving adhesion.

[0063] In some embodiments, the organic modifier of the organically modified montmorillonite includes a silane coupling agent.

[0064] The silane coupling agent includes at least one of the following: KH550 silane coupling agent and KH560 silane coupling agent.

[0065] Montmorillonite modified with the above-mentioned silane coupling agent has a good affinity with epoxy-based POSS and epoxy-terminated polybutadiene liquid rubber, which can promote its uniform dispersion in the system. This is beneficial for the foaming agent to form a small and dense closed-cell structure in the interlayer voids, thereby improving the moisture resistance of the shock-absorbing expansion rubber.

[0066] In some embodiments, the rubber preferably includes styrene-butadiene rubber and cis-butadiene rubber.

[0067] In some embodiments, the weight ratio of the styrene-butadiene rubber to the butadiene rubber is 2:1.

[0068] In order to balance the flexibility of the long carbon chain in the rubber and the high temperature resistance of the benzene ring, the weight ratio of the styrene-butadiene rubber to the butadiene rubber is 2:1.

[0069] In some embodiments, the epoxy resin includes at least one of the following: bisphenol A diglycidyl ether type epoxy resin and bisphenol F diglycidyl ether type epoxy resin.

[0070] Among them, bisphenol A diglycidyl ether type epoxy resin includes E51 epoxy resin, and bisphenol F diglycidyl ether type epoxy resin includes NPEF170 epoxy resin.

[0071] In some embodiments, the foaming agent is preferably 4,4'-oxobisbenzenesulfonylhydrazine.

[0072] The foaming agent has a moderate foaming amount and foaming rate, and the N2 released during foaming is difficult to escape from the rubber. It works synergistically with epoxy-based POSS and organically modified montmorillonite to help the foaming agent form a small and dense closed-cell structure. This closed-cell structure helps to block the transmission path of water vapor inside the shock-absorbing expansion rubber, thereby improving moisture resistance.

[0073] like Figure 1 As shown, based on a general inventive concept, this application also provides a method for preparing a shock-absorbing expansion adhesive, comprising:

[0074] S1. Styrene-butadiene rubber, cis-butadiene rubber and dioctyl phthalate are compounded to obtain a first mixture;

[0075] S2. The epoxy group POSS, epoxy-terminated polybutadiene liquid rubber, organically modified montmorillonite, epoxy resin, dicyandiamide, diisopropylbenzene peroxide, zinc oxide, foaming agent, dioctyl phthalate 2, and calcium carbonate are kneaded in the first step to obtain the second mixture.

[0076] S3. The first mixture, the second mixture, and the third dioctyl phthalate are kneaded for the second time, followed by vacuum degassing to obtain a shock-absorbing and expanding adhesive.

[0077] To improve the compatibility and dispersibility of the components in the second mixture, step S2 can be specifically as follows: the mixture of epoxy-based POSS, epoxy-terminated polybutadiene liquid rubber, organically modified montmorillonite, epoxy resin, dicyandiamide, diisopropylbenzene peroxide, zinc oxide, foaming agent, dioctyl phthalate 2, and calcium carbonate is divided into multiple portions, either uniformly or unevenly. After kneading one portion, the next portion is added and kneaded until each portion is completely kneaded. The kneading time for each kneading can be the same or different, and finally the second mixture is obtained.

[0078] In some embodiments, the contents of the first dioctyl phthalate, the second dioctyl phthalate, and the third dioctyl phthalate may be the same or different, and the total content of the three is 20-25% by weight.

[0079] In some embodiments, the mixing process parameters include: a mixing temperature of 95-105°C and a mixing time of 10-15 min. For example, the mixing process parameters may be a mixing temperature of 95°C and a mixing time of 15 min, a mixing temperature of 100°C and a mixing time of 12 min, or a mixing temperature of 105°C and a mixing time of 15 min.

[0080] In some implementations, the total time for the first kneading is 15-20 minutes. For example, the total time for the first kneading can be 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0081] In some embodiments, the second kneading time is 25-30 minutes. For example, the second kneading time can be 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or 30 minutes.

[0082] In some embodiments, the pressure of the vacuum degassing is -1 MPa.

[0083] Based on a general inventive concept, embodiments of this application also provide an application of a shock-absorbing expansion adhesive.

[0084] The expanding adhesive is used for bonding coated steel sheets to various components in the automotive industry. Currently, galvanized or zinc-aluminum-magnesium steel sheets are commonly used as the outer panels for the four doors, two hoods, and roof beams in the automotive industry. To reduce vibration, noise, and safety issues during vehicle operation, the expanding adhesive can be used to bond the coated steel sheets to components such as reinforcing ribs.

[0085] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0086] Example 1

[0087] S101. 160g of styrene-butadiene rubber, 80g of cis-butadiene rubber, and 80g of dioctyl phthalate were put into a mixer and mixed at 105°C for 15 minutes to obtain the first mixture.

[0088] S201. A mixture of 12g epoxy-based POSS, 43g epoxy-terminated polybutadiene liquid rubber, 1.2g organically modified montmorillonite, 33g E51 epoxy resin, 25g NPEF170 epoxy resin, 3.5g dicyandiamide, 4.5g dicumyl peroxide, 4.5g zinc oxide, 2g 4,4'-oxobisbenzenesulfonyl hydrazine, 80g dioctyl phthalate, and 391.3g calcium carbonate is evenly divided into three portions. Each portion is added to a kneader and kneaded, and then the next portion is added and kneaded until each portion is completely kneaded. Each kneading lasts for 5 minutes to obtain the second mixture.

[0089] S301. The first mixture, the second mixture and 80g of dioctyl phthalate were put into a kneader and kneaded for 25 minutes. Then, the mixture was degassed under vacuum at a pressure of -1MPa to obtain a shock-absorbing expansion adhesive (denoted as shock-absorbing expansion adhesive A).

[0090] Example 2

[0091] This example provides a shock-absorbing expansion adhesive (denoted as shock-absorbing expansion adhesive B), which differs from Example 1 in that: styrene-butadiene rubber is 140g, cis-butadiene rubber is 70g, and dioctyl phthalate is 70g; epoxy-based POSS is 18g, terminal epoxy-based polybutadiene liquid rubber is 43g, organically modified montmorillonite is 2.5g, E51 epoxy resin is 32g, NPEF170 epoxy resin is 30g, dicyandiamide is 4.5g, dicumyl peroxide is 3.5g, zinc oxide is 3.5g, 4,4'-oxobis(benzenesulfonyl)hydrazine is 3.5g, dioctyl phthalate is 70g, and calcium carbonate is 439.5g; dioctyl phthalate is 70g; all other parameters and steps are the same.

[0092] Example 3

[0093] This example provides a shock-absorbing expansion adhesive (denoted as shock-absorbing expansion adhesive C), which differs from Example 1 in that: styrene-butadiene rubber is 150g, butadiene rubber is 75g, dioctyl phthalate is 70g; epoxy-based POSS is 15g, terminal epoxy-based polybutadiene liquid rubber is 40g, organically modified montmorillonite is 2g, E51 epoxy resin is 30g, NPEF170 epoxy resin is 30g, dicyandiamide is 4g, dicumyl peroxide is 4g, zinc oxide is 4g, 4,4'-oxobis(benzenesulfonyl)hydrazine is 3g, dioctyl phthalate is 70g, calcium carbonate is 423g; and dioctyl phthalate is 80g. All other parameters and steps are the same.

[0094] Example 4

[0095] This example provides a shock-absorbing expansion adhesive (denoted as shock-absorbing expansion adhesive D), which differs from Example 1 in that: styrene-butadiene rubber is 140g, cis-butadiene rubber is 70g, dioctyl phthalate is 70g; epoxy-based POSS is 15g, terminal epoxy-based polybutadiene liquid rubber is 37g, organically modified montmorillonite is 2g, E51 epoxy resin is 30g, NPEF170 epoxy resin is 32g, dicyandiamide is 4.5g, dicumyl peroxide is 3.5g, zinc oxide is 3.5g, 4,4'-oxobis(benzenesulfonyl)hydrazine is 2.5g, dioctyl phthalate is 70g, calcium carbonate is 430g; and dioctyl phthalate is 90g. All other parameters and steps are the same.

[0096] The components and contents of the shock-absorbing expansion adhesives prepared in Examples 1-4 are shown in Table 1.

[0097] Table 1. Components and content (wt%) of each embodiment

[0098]

[0099] Comparative Example 1

[0100] This example provides a shock-absorbing expansion adhesive (denoted as shock-absorbing expansion adhesive F), which differs from Example 1 in that the epoxy-terminated polybutadiene liquid rubber is removed, while the other parameters and steps are the same.

[0101] Experimental Test

[0102] To better illustrate the damp heat resistance of the shock-absorbing expansion adhesive provided in this application, the shock-absorbing expansion adhesives obtained in Examples 1-4 and Comparative Example 1 were experimentally tested.

[0103] Preparation of coated steel sheet samples: Prepare 100mm×25mm samples of hot-dip galvanized steel sheet and hot-dip galvanized aluminum-magnesium steel sheet with a thickness of 0.7mm for later use.

[0104] Preparation of adhesive joints: Using PTFE gaskets, the adhesive layer thickness is controlled to be 2mm to make single lap joints. Each group consists of 3 parallel samples. After standing at room temperature for 24 hours, they are cured in an oven at 170℃ for 20 minutes and then taken out and left to stand in the air for more than 24 hours.

[0105] Humid heat aging test: The bonded sample was placed in a humid heat chamber at a temperature of 50±2℃ and a relative humidity of 95%RH for 480h, and then removed and left to stand at room temperature for more than 24h.

[0106] Shear and tensile test: Tensile and shear tests were conducted on the adhesive samples before and after the damp heat aging test according to the national standard GB / T 7124—2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)". The average shear strength and cohesive failure ratio are shown in Tables 2 and 3 below.

[0107] Table 2 shows the average shear strength (MPa) and retention rate (%) of each embodiment and comparative example.

[0108]

[0109] Table 3. Average cohesion failure rate (%) for each embodiment and comparative example.

[0110]

[0111] As shown in Tables 2 and 3, the damping expansion adhesives prepared in Examples 1-4 exhibit excellent resistance to damp heat on both galvanized and zinc-aluminum-magnesium coated steel, with shear strength retention rates all exceeding 95%, and the fracture surface failure mode being 100% adhesive cohesive failure. In contrast, the damping expansion adhesive prepared in Comparative Example 1, after damp heat aging, only retained 60-62% of its shear strength, and the fracture surface tended towards interfacial failure. Therefore, it can be concluded that the damping expansion adhesive obtained using the preparation method provided in this application possesses excellent resistance to damp heat, solving the technical problem of insufficient resistance to damp heat in current damping expansion adhesives.

[0112] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A shock-absorbing expansion adhesive, characterized in that, The components of the expanding adhesive include: epoxy-based POSS: 1-2 wt%, terminal epoxy-based polybutadiene liquid rubber: 3.5-4.5 wt%, organically modified montmorillonite: 0.1-0.3 wt%, rubber: 20-25 wt%, epoxy resin: 5.5-6.5 wt%, dicyandiamide: 0.3-0.5 wt%, dicumyl peroxide: 0.3-0.5 wt%, zinc oxide: 0.3-0.5 wt%, foaming agent: 0.15-0.4 wt%, dioctyl phthalate: 20-25 wt%, and calcium carbonate: 38-45 wt%. The structural formula of the epoxy group POSS is shown in Formula I: Formula I In Formula I, R1, R2, R3, R4, R5, R6, R7 and R8 may be the same or different, and each is independently selected from aliphatic chains containing epoxy groups; The aliphatic chain containing epoxy groups includes at least one of the following: 2,3-epoxypropoxypropyl, 3,4-epoxycyclohexylethyl; The end-capping structure of the epoxy-terminated polybutadiene liquid rubber includes at least one of the following: a single-terminated epoxy-terminated structure and a double-terminated epoxy-terminated structure; The organic modifiers in the organically modified montmorillonite include silane coupling agents.

2. The shock-absorbing expansion adhesive according to claim 1, characterized in that, The rubbers include styrene-butadiene rubber and cis-butadiene rubber.

3. The shock-absorbing expansion adhesive according to claim 2, characterized in that, The weight ratio of the styrene-butadiene rubber to the butadiene rubber is 2:

1.

4. The shock-absorbing expansion adhesive according to claim 1, characterized in that, The epoxy resin includes at least one of the following: bisphenol A diglycidyl ether type epoxy resin and bisphenol F diglycidyl ether type epoxy resin.

5. A method for preparing a shock-absorbing expansion adhesive according to any one of claims 1 to 4, characterized in that, The preparation method includes: Styrene-butadiene rubber, cis-butadiene rubber, and dioctyl phthalate were compounded to obtain a first mixture; The epoxy group POSS, epoxy-terminated polybutadiene liquid rubber, organically modified montmorillonite, epoxy resin, dicyandiamide, dicumyl peroxide, zinc oxide, foaming agent, dioctyl phthalate 2, and calcium carbonate are first kneaded to obtain a second mixture. The first mixture, the second mixture, and the third dioctyl phthalate were kneaded a second time, followed by vacuum degassing to obtain a shock-absorbing and expanding adhesive.

6. The application of a shock-absorbing expansion adhesive according to any one of claims 1 to 4, characterized in that, The expanding adhesive is used for bonding coated steel sheets to various components in the automotive field.

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