Ultrahigh-temperature corrosion-resistant epoxy structural adhesive capable of being cured at low temperature and preparation method thereof

Abstract

The invention relates to the technical field of epoxy structural adhesives, in particular to a low-temperature-curable ultrahigh-temperature corrosion-resistant epoxy structural adhesive which comprises the following components in parts by weight: 100 parts of polyfunctional group resin, 10-20 parts of a chain extender, 5-30 parts of a curing agent, 1-10 parts of an accelerant, 2-10 parts of reinforcing filler, 1-5 parts of a reinforcing treatment agent and 1-5 parts of color paste. And the chip is bonded and fixedly connected with the ceramic substrate by the epoxy structural adhesive. According to the invention, the problems that the chip adhesive for chip ceramic packaging cannot be cured at high temperature and needs to resist high temperature, acid and alkali and solvent corrosion after being cured are solved.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy structural adhesives, in particular to an ultra-high temperature corrosion-resistant epoxy structural adhesive that can be cured at low temperatures. Background Art

[0002] Plastic packaging is the main technology used in microelectronic packaging and occupies a dominant position in chip packaging. Its advantages are low cost, simple method, and high-density integration, but it also has obvious disadvantages, namely poor air tightness, poor moisture resistance, easy to be affected by ions, and interfered by electromagnetic waves, which greatly affects its reliability. Therefore, the trend of chip packaging in the future will gradually eliminate plastic packaging and adopt ceramics and other forms for high-reliability applications. The form of ceramic packaging will inevitably put forward higher requirements for other packaging materials in terms of high temperature resistance, corrosion resistance, and low CTE matching. At present, the confidentiality fixing glue used for chip packaging in the industry is the adhesive glue for protecting the sealing and fixing function. The epoxy glue that can resist acid and alkali corrosion can generally only withstand a temperature of about 300°C, and faces colloid degradation and carbonization at 400°C, while the epoxy glue that can withstand high temperatures of 500°C-700°C faces the problem of being unable to withstand acid, alkali, and solvent corrosion. In addition, in the packaging process, in order to protect components such as capacitors from damage, the confidentiality glue can only be cured at a temperature below 100°C (for plastic packaging technology), which forms a pair of technical contradictions with extremely high temperature resistance and high storage stability. Therefore, there is an urgent need for a structural adhesive that can cure at low temperatures, withstand extremely high temperatures, withstand acid, alkali and solvent corrosion, and has excellent adhesion to ceramic substrates to match the rapidly developing chip packaging technology. Summary of the invention

[0003] In order to solve the above technical problems, the present invention adopts the following technical solution: The purpose of this application is to provide a low-temperature curable ultra-high temperature corrosion-resistant epoxy structural adhesive and a preparation method thereof, which has the advantages of curing at low temperature, withstanding ultra-high temperature of 500℃-700℃, resistant to acid and alkali corrosion and strong adhesion to ceramic substrates.

[0004] The present application provides an ultra-high temperature corrosion-resistant epoxy structural adhesive that can be cured at low temperature. The technical scheme is as follows: it comprises an epoxy structural adhesive with the following components in proportion by weight: 100 parts of a multi-functional resin, 10-20 parts of a chain extender, 5-30 parts of a curing agent, 1-10 parts of an accelerator, 2-10 parts of a reinforcing filler, 1-5 parts of a reinforcing treatment agent, and 1-5 parts of a color paste. The epoxy structural adhesive bonds and fixes the chip to a ceramic substrate. The curing temperature of the epoxy structural adhesive is 100°C-170°C, and the maximum temperature resistance range is 500°C-700°C.

[0005] Furthermore, the present application also proposes that the epoxy structural adhesive of the present invention is a single-component structural adhesive, the curing temperature is 100°C-170°C for 4 hours, and the shear strength on the aluminum substrate is 14-16 MPa.

[0006] Furthermore, the present application also proposes that the shear strength of the epoxy structural adhesive is reduced by less than 5% after being immersed in a 5% acetic acid solution for 7 days; the shear strength of the epoxy structural adhesive is reduced by less than 10% after being immersed in a 1% sodium hydroxide solution for 7 days. The epoxy structural adhesive of the present invention has an effective shear strength of 0.5-5MPa after being kept in a muffle furnace at 500°C for 24 hours or a muffle furnace at 700°C for 5 minutes.

[0007] Furthermore, the present application also proposes that the multifunctional resin is one or more of triglycidyl p-aminophenol, phenolic resin, tetraglycidylamine, naphthol-type resin, and tetraepoxypropyl-4,4\'-diaminodiphenylmethane.

[0008] Furthermore, the present application also proposes that the chain extender is one or more of styrene-glycidyl methacrylate, phosphite, dioxazoline, glycidyl methacrylate, and 3,3'-diethyl 4,4'-diaminodiphenylmethane. Furthermore, the present application also proposes that the accelerator is a diaminoimidazole triazine complex and 2-ethyl-4-methylimidazole.

[0009] Furthermore, the present application also proposes that the reinforcing filler is one or more of silicon micropowder, aluminum hydroxide, aluminum oxide, quartz powder, mica powder, and kaolin.

[0010] Furthermore, the present application also proposes that the reinforcing agent is one or more of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0011] Furthermore, the present application also proposes that the preparation method includes the following steps: dispersing the multifunctional resin, chain extender, curing agent, and color paste at high speed at room temperature, stirring at a speed of 1200r / min for 2 hours, vacuuming while dispersing, and the vacuum degree is -100kPa, and then continuing to add reinforcing filler for dispersion, stirring at a speed of 1000r / min for 30 minutes, continuing to add accelerator and dispersing and stirring at a speed of 1000r / min for 30 minutes, vacuuming while dispersing, and the vacuum degree is -100kPa, and finally adding reinforcing treatment agent, stirring at a speed of 1000r / min for 30 minutes, and vacuuming while dispersing, and the vacuum degree is -100kPa.

[0012] From the above, it can be seen that the present application provides a low-temperature curable ultra-high temperature corrosion-resistant epoxy structural adhesive and a preparation method thereof. Through specific component ratios and processes, it can still withstand high temperatures of 500°C-700°C and acid and alkali corrosion after low-temperature curing, while maintaining excellent adhesion to the ceramic substrate. It has the advantages of curing at low temperatures, withstanding ultra-high temperatures, corrosion resistance and high reliability. DETAILED DESCRIPTION

[0013] The technical scheme in the present application is clearly and completely described below, and it is obvious that the described embodiments are only a part of embodiments of the present application, rather than all embodiments. The components of the present application generally described and shown here can be designed with various configurations. Therefore, the detailed description of the embodiments of the present application provided below is not intended to limit the scope of the present application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0014] In the existing technology, plastic packaging technology is widely used in the field of microelectronics due to its low cost and simple process, but it has defects such as poor air tightness, weak moisture resistance, and susceptibility to electromagnetic interference. Ceramic packaging has gradually become a trend in high-reliability applications, which puts higher requirements on the high temperature resistance, corrosion resistance and thermal expansion coefficient matching of packaging materials. Traditional epoxy structural adhesives have corrosion resistance below 300°C, but the colloid is prone to carbonization and degradation when it exceeds 400°C; some epoxy adhesives that are resistant to high temperatures of 500-700°C are difficult to resist acid and alkali solvent erosion. At the same time, the chip packaging process requires a curing temperature below 100°C (for plastic packaging technology), which is a technical contradiction with the high temperature tolerance and storage stability of the material.

[0015] In order to solve the above problems, the key contradiction that the existing epoxy adhesive system cannot meet the requirements of low-temperature curing and ultra-high temperature tolerance at the same time was identified. By analyzing the relationship between cross-linking density and thermal stability, it was found that increasing the density of the cross-linking network can enhance the thermal decomposition temperature; studying the characteristics of the resin functional groups, it was found that multi-functional groups can construct a three-dimensional network structure; examining the interface bonding mechanism, it was found that the synergy of reinforcing fillers and treatment agents can enhance the bonding strength of ceramic substrates. On this basis, a multi-component synergistic model was established: a skeleton network was constructed through multi-functional resins, chain extenders adjusted the flexibility of the molecular chains, a curing promotion system reduced the activation energy, and a reinforcement system strengthened the interface bonding, ultimately forming a balance between low-temperature curing and high-temperature tolerance.

[0016] Therefore, the present application proposes a low-temperature curable ultra-high temperature corrosion-resistant epoxy structural adhesive, including the following epoxy structural adhesive with the following weight proportions of each component: 100 parts of multifunctional resin, 10-20 parts of chain extender, 5-30 parts of curing agent, 1-10 parts of accelerator, 2-10 parts of reinforcing filler, 1-5 parts of reinforcing treatment agent, 1-5 parts of color paste, the epoxy structural adhesive bonds the chip to the ceramic substrate, the epoxy structural adhesive curing temperature is 100℃-170℃, and the maximum temperature resistance range is 500℃-700℃. The curing temperature of the epoxy structural adhesive is 100℃-170℃. This temperature belongs to low-temperature curing in the sealing process of bonding and fixing the chip to the ceramic substrate, relative to its working temperature with a maximum temperature resistance range of 500℃-700℃.

[0017] Among them, multifunctional resin refers to a polymer compound with more than three epoxy groups, which can be specifically achieved by triglycidyl para-aminophenol or tetraglycidylamine, and the thermal stability is improved through a high-density cross-linked network. Chain extender refers to a modifier that can extend the molecular chain, which can be specifically achieved by styrene-methacrylate glycidyl ester or dioxazoline, and is used to adjust the curing stress and thermal expansion coefficient matching. Reinforcing filler refers to inorganic particles that enhance mechanical properties, which can be specifically achieved by silicon micropowder or alumina, and the ceramic interface bonding strength is improved by synergistic action with the reinforcing treatment agent. Reinforcing treatment agent refers to a silane coupling agent containing active groups, which can be specifically achieved by γ-aminopropyltriethoxysilane, and a chemical bond is established between the filler and the resin.

[0018] Specifically, the multifunctional resin forms a three-dimensional cross-linked network, and its high-density epoxy group generates a stable carbon-oxygen bond structure during the curing process, which significantly increases the glass transition temperature of the cured product. The active groups in the chain extender undergo a grafting reaction with the resin chain segments, introducing flexible segments to buffer thermal stress while maintaining the regularity of the molecular chain. After the reinforcing filler is surface-modified by a silane treatment agent, its surface hydroxyl groups form covalent bonds with the alkoxy groups of the treatment agent, forming a chemical anchoring effect on the surface of the ceramic substrate. The curing promotion system regulates the reaction activation energy so that the cross-linking reaction can be carried out efficiently in the low temperature range, avoiding thermal damage to components caused by high temperature.

[0019] Compared with the existing technology, traditional epoxy adhesives usually use the method of reducing crosslinking density to balance low-temperature curing and high-temperature performance, but this leads to a decrease in thermal stability. This solution introduces flexible segments while maintaining sufficient crosslinking density through the synergy of multifunctional resins and chain extenders, which not only meets the low-temperature curing requirements but also maintains structural stability at high temperatures. The existing reinforcement system mostly uses physical filling, while this solution achieves a strong three-phase combination of filler-resin-substrate through chemical bonding, significantly improving the interface durability.

[0020] Through the above technical solution, the present application realizes the formation of a stable three-dimensional cross-linked network under low-temperature curing conditions of 100-170°C, so that the cured product maintains structural integrity under high-temperature environments of 500-700°C. The chemical bonding interface established by the silane treatment agent effectively resists the erosion of acid and alkali solutions, while ensuring reliable bonding between the ceramic substrate and the chip. The synergistic effect of multiple components solves the contradiction between low-temperature process and high-temperature performance, and meets the requirements of advanced packaging technology for comprehensive material performance.

[0021] The present application further proposes that the epoxy structural adhesive is a single-component structural adhesive, the curing temperature is 100° C.-170° C. for 4 hours, and the shear strength on the aluminum substrate is 14-16 MPa.

[0022] Among them, single-component structural adhesive refers to a pre-mixed adhesive system that does not require on-site proportioning. It can be achieved by pre-reacting a multi-functional resin with a chain extender and a curing agent to form a stable system. This design avoids the mixing error of the two-component adhesive and prolongs the storage stability. The curing temperature of 100℃-170℃ for 4 hours refers to the control of the curing process by gradient temperature increase in the packaging process. It can be achieved by using a segmented heating device. This temperature range ensures that heat-sensitive components are not damaged while meeting the activation energy requirements of the cross-linking reaction. The shear strength of the aluminum substrate is 14-16MPa, which means that the shear resistance between the aluminum substrate and the cured adhesive layer is tested by a peel tester according to the ASTMD1002 standard. This indicator shows that the colloid forms a chemical bond and mechanical interlocking effect at the metal interface.

[0023] Specifically, the single-component structural adhesive forms a reactive prepolymer system by pre-completing the polycondensation reaction of the resin and the chain extender. During the curing process, only thermal activation is required to complete the cross-linking reaction. The lower limit of the curing temperature is set to 100°C to avoid insufficient cross-linking density caused by low-temperature curing. The upper limit of 170°C combined with a 4-hour insulation time can ensure that the molecular chain is fully stretched and forms a dense three-dimensional network structure. The shear strength is achieved by adjusting the particle size distribution of the reinforcing filler and the coupling effect of the reinforcing treatment agent. For example, silicon micropowder and γ-aminopropyltriethoxysilane synergistically enhance the interfacial bonding force, so that the surface oxide layer of the aluminum substrate forms a -Si-O-Al- covalent bond with the colloid.

[0024] Compared with the existing technology, traditional two-component epoxy adhesives require precise control of the mixing ratio and have a short application period, while the single-component system directly simplifies the gluing process and eliminates operational errors; existing low-temperature curing adhesives mostly use a curing process below 80°C, which leads to incomplete cross-linking. This solution optimizes the resin functionality and the activity of the curing agent to complete a full reaction above 100°C; the shear strength of conventional aluminum substrate adhesives is mostly lower than 12MPa. This solution achieves higher bonding strength through the synergistic effect of interface treatment agents and fillers.

[0025] Through the above technical scheme, the present application solves the problem of decreased bonding strength caused by insufficient colloid cross-linking under low-temperature curing conditions, avoids bubbles and proportion errors introduced in the two-component adhesive mixing process, ensures the interface stability between the aluminum substrate and the adhesive layer in high and low temperature cycles and corrosive environments, and meets the dual requirements of ceramic packaging technology for ease of operation and reliability.

[0026] The present application further proposes a technical solution in which the shear strength reduction of the epoxy structural adhesive is controlled within 5% after being immersed in a 5% acetic acid solution and a 1% sodium hydroxide solution for 7 days respectively.

[0027] Among them, the acetic acid solution concentration of 5% refers to an acidic corrosive medium environment with a volume fraction of 5%. Specifically, acetic acid and deionized water can be mixed in proportion to simulate the swelling and chemical corrosion of the acid on the colloid in actual working conditions. The sodium hydroxide solution concentration of 1% refers to an alkaline corrosive medium with a mass fraction of 1%. Specifically, sodium hydroxide particles can be dissolved in deionized water to prepare it, which is used to verify the chemical stability of the colloid in an alkaline environment. The immersion time of 7 days refers to a continuous corrosion test cycle. For example, it can be set as a static immersion experiment under constant temperature conditions to accelerate the evaluation of the performance degradation law of the colloid when it is exposed to chemical media for a long time.

[0028] Specifically, by optimizing the distribution of corrosion-resistant groups in the resin system, such as introducing phenolic hydroxyl groups and benzene ring structures, the barrier capacity of the cross-linked network to acid-base media can be enhanced. The surface of the reinforcing filler is treated with a silane coupling agent, such as using γ-aminopropyltriethoxysilane to coat silicon micropowder, which can reduce the interface defects between the filler and the resin and inhibit the penetration of corrosive media along the interface. The synergistic effect of the curing agent and the chain extender forms a dense three-dimensional network. For example, by reacting the dioxazoline chain extender with triglycidyl para-aminophenol resin, the gaps between the molecular chain segments can be reduced, hindering the diffusion of acid-base molecules into the adhesive layer.

[0029] Compared with the existing technology, the shear strength of traditional epoxy adhesives generally decreases by more than 15% after being immersed in alkaline solutions of the same concentration for the same time. This is mainly due to the lack of corrosion-resistant groups in the resin system and insufficient filler interface treatment, which makes it easy for the corrosive medium to diffuse along the filler-resin interface, causing the adhesive layer to swell and crack. This solution significantly improves the structural stability of the colloid in an alkaline environment by constructing a double corrosion-resistant barrier to block medium penetration in two dimensions: the resin cross-linking network and the filler interface.

[0030] Through the above technical solution, the present application effectively solves the problem of bonding strength attenuation of epoxy structural adhesive caused by medium penetration in an alkaline corrosive environment. By controlling the shear strength drop within 10%, it can ensure that the colloid still maintains reliable mechanical connection performance when in long-term contact with alkaline media, avoiding chip packaging structure from failing due to chemical corrosion.

[0031] The present application further proposes that the epoxy structural adhesive has an effective shear strength of 0.5-5 MPa after being kept in a muffle furnace at 500° C. for 24 hours or in a muffle furnace at 700° C. for 5 minutes.

[0032] Among them, keeping the 500℃ muffle furnace for 24 hours means placing the cured epoxy structural adhesive in a high temperature environment for a long-term thermal stability test, which can be achieved by using a program-controlled temperature muffle furnace, and simulating the performance of the material under continuous high temperature conditions through constant high temperature treatment. Among them, keeping the 700℃ muffle furnace for 5 minutes means subjecting the cured epoxy structural adhesive to a short-term high temperature impact test, which can be achieved by using a fast heating muffle furnace, and simulating the tolerance under extreme thermal shock conditions through instantaneous high temperature exposure. Among them, soaking in 5% acetic acid solution and 1% sodium hydroxide solution for 7 days means conducting acidic and alkaline medium corrosion tests on samples after high temperature treatment, which can be achieved by using a constant temperature immersion device, and verifying the degree of mechanical property attenuation of the material under the dual effects of extreme temperature and corrosive environment through long-term chemical erosion.

[0033] Specifically, by setting the high temperature treatment conditions of 500℃ for 24 hours or 700℃ for 5 minutes, the thermal decomposition and cross-linking structure stability of the epoxy structural adhesive under long-term stable high temperature and instantaneous thermal shock were investigated respectively. Subsequently, the samples after high temperature treatment were immersed in acidic and alkaline solutions for a long time to simultaneously evaluate the material's resistance to corrosive media after thermal degradation. The design of this dual test condition can effectively simulate the extreme working conditions that the material may face in actual applications, such as acid-base corrosion in a high temperature environment or chemical erosion after instantaneous thermal shock, indicating that the epoxy structural adhesive can still maintain sufficient interface bonding strength after experiencing the synergistic effect of high temperature and corrosion.

[0034] Compared with the existing technology, the corrosion resistance of traditional high temperature resistant epoxy adhesives is significantly reduced due to carbonization or destruction of the cross-linking network after high temperature treatment above 500°C, and the existing corrosion resistant epoxy adhesives are prone to thermal decomposition in high temperature environments and cannot meet the requirements of both high temperature and corrosion. This solution can still form a stable corrosion-resistant barrier after high temperature treatment by optimizing the synergy of the resin matrix and the filler system, thus overcoming the technical bottleneck of balancing high temperature and corrosion performance.

[0035] Through the above technical scheme, the present application solves the problem that the acid and alkali corrosion resistance of epoxy structural adhesive decreases and there is almost no shear force after extreme high temperature treatment, ensuring that the material can still effectively resist the corrosion of acidic and alkaline media after long-term heat exposure at 500°C or instantaneous heat shock at 700°C, and maintain stable shear strength, thereby improving its reliability and service life under high-temperature corrosion composite working conditions.

[0036] The present application further proposes that the multifunctional resin is one or more of triglycidyl p-aminophenol, phenolic resin, tetraglycidylamine, naphthol-type resin, and tetraepoxypropyl-4,4'-diaminodiphenylmethane.

[0037] Among them, triglycidyl para-aminophenol refers to an epoxy resin containing three epoxy groups combined with a rigid skeleton of a benzene ring. Specifically, it can be achieved by the condensation reaction of the amino group on the benzene ring with propylene oxide, and the structural stability is enhanced by a three-dimensional cross-linked network. Among them, phenolic resin refers to a thermosetting resin formed by the polycondensation of phenolic compounds and aldehydes. Specifically, it can be achieved by the condensation of phenol and formaldehyde under acidic conditions, and the heat resistance is improved by high-density phenolic hydroxyl cross-linking. Among them, tetraglycidylamine refers to an amine derivative with four epoxy groups, which can be achieved by the reaction of tetraamino compounds with epichlorohydrin, and a tight network structure is formed by multi-point cross-linking. Among them, naphthol-type resin refers to an epoxy resin with a naphthalene ring as a skeleton, which can be achieved by the condensation of β-naphthol with epichlorohydrin, and the rigid structure of condensed aromatic hydrocarbons resists high-temperature deformation. Among them, tetraepoxypropyl-4,4'-diaminodiphenylmethane refers to a double benzene ring structure compound containing four epoxy groups, which can be specifically achieved by reacting 4,4'-diaminodiphenylmethane with epichlorohydrin to enhance the ability to resist medium penetration through symmetrical cross-linking.

[0038] Specifically, by selecting resins containing multiple epoxy groups or rigid skeletons as the base material, a higher density cross-linked network is formed during the curing process. The benzene ring structure of triglycidyl p-aminophenol combines with three epoxy groups to form a three-dimensional cross-linking during curing; the phenolic hydroxyl group of phenolic resin condenses with the aldehyde group to form a high cross-linking density network structure; the four epoxy groups of tetraglycidylamine achieve multi-point cross-linking; the condensed aromatic hydrocarbon skeleton of naphthol-type resin remains stable at high temperatures; the double benzene ring structure of tetraepoxypropyl-4,4'-diaminodiphenylmethane forms a symmetrical network with four epoxy groups. When these resins are used alone or in combination, their multi-functional characteristics significantly increase the cross-linking density of the cured product, thereby reducing the thermal motion of the molecular chain segments at high temperatures and hindering the diffusion path of the corrosive medium.

[0039] Compared with the prior art, traditional epoxy adhesives mostly use bisphenol A epoxy resin as the matrix, which has a functionality of only 2, resulting in a low crosslinking density. However, the present application uses a multifunctional resin with a functionality ≥ 3, such as tetraglycidylamine, which contains four epoxy groups. During curing, each molecule can participate in four crosslinking reactions, which doubles the network density. In addition, the condensed aromatic hydrocarbon structure of the naphthol-type resin has higher thermal stability than the isolated benzene ring of bisphenol A, and the phenolic hydroxyl crosslinking network of the phenolic resin is more resistant to acid and alkali corrosion than the ether bond of ordinary epoxy resin.

[0040] Through the above technical scheme, the present application solves the problem of performance degradation of epoxy structural adhesive caused by insufficient cross-linking density in high temperature and corrosive environment, so that the cured colloid forms a denser three-dimensional network structure, effectively inhibiting high-temperature thermal decomposition and penetration of corrosive media, thereby achieving long-term stable bonding in high temperature of 500℃-700℃ and acid-base corrosion environment.

[0041] The present application further proposes that the chain extender is one or more of styrene-glycidyl methacrylate, phosphite, dioxazoline, glycidyl methacrylate, and 3,3'-diethyl 4,4'-diaminodiphenylmethane.

[0042] Among them, styrene-methacrylate glycidyl ester refers to a copolymer containing styrene groups and glycidyl ester groups, which can be prepared by free radical polymerization, and its double bond structure can react with epoxy groups to form a cross-linked network, and the glycidyl ester group can enhance the hydrolysis resistance of the resin system. Among them, phosphite refers to a compound containing a phosphite group, and specifically, organic phosphites such as triphenylphosphite can be used, which has an antioxidant function and can inhibit the chain degradation reaction caused by free radicals under high temperature conditions. Among them, dioxazoline refers to a nitrogen-containing heterocyclic compound, and specifically, bifunctional dioxazoline can be used, and its rigid ring structure can enhance the heat deformation resistance of the cross-linked network. Among them, glycidyl methacrylate refers to a monomer containing an acrylate group and a glycidyl ester group, and specifically, it can be prepared by an esterification reaction, and its acrylate segment can improve the interfacial bonding strength with the ceramic substrate. Among them, 3,3'-diethyl 4,4'-diaminodiphenylmethane refers to a chain extender containing an aromatic amine group, and specifically, it can be synthesized by an alkylation reaction, and its aromatic amine structure can enhance the acid and alkali corrosion resistance of the resin system.

[0043] Specifically, styrene-glycidyl methacrylate reacts with epoxy resin through double bonds to form a long-chain cross-linked structure to improve ductility, while its glycidyl ester group reduces the degradation rate of the resin system in an acid-base environment through hydrolysis stability. The introduction of phosphite inhibits the breakage of the resin main chain at high temperature by capturing free radicals, delaying the thermal decomposition process. The rigid ring structure of dioxazoline reacts with the epoxy group to form a stable three-dimensional network, which limits the thermal motion of the molecular chain at high temperature. The acrylate segment of glycidyl methacrylate enhances the adhesion to the surface of the ceramic substrate through polar interactions and reduces interfacial defects. The aromatic amine group of 3,3'-diethyl 4,4'-diaminodiphenylmethane reacts with the epoxy group to form corrosion-resistant aromatic ring cross-linking points, while the ethyl substituent can adjust the reaction activity to avoid excessive cross-linking during low-temperature curing. The combined use of the above chain extenders forms a network structure with high cross-linking density and chemical stability during the curing process.

[0044] Compared with the existing technology, traditional chain extenders mostly use a single type of amino or anhydride compounds, which are difficult to balance heat resistance and corrosion resistance. For example, amino chain extenders are prone to oxidative degradation at high temperatures, while anhydride chain extenders are prone to hydrolysis and failure in alkaline environments. This solution introduces the synergistic effect of multiple types of chain extenders to simultaneously construct antioxidant, hydrolysis-resistant and high-rigidity structural units in the molecular chain, thereby overcoming the performance limitations of a single chain extender in extreme environments.

[0045] Through the above technical scheme, the present application can effectively improve the segment stability of epoxy structural adhesive in high temperature and corrosive media, inhibit the degradation and breakage of the cross-linked network, thereby enhancing the heat resistance, chemical corrosion resistance and mechanical strength of the adhesive layer after curing, and meet the long-term reliability requirements of ceramic packaging for structural adhesives.

[0046] The present application further proposes a technical solution in which the accelerator is a diaminoimidazole triazine complex and 2-ethyl-4-methylimidazole.

[0047] Among them, diaminoimidazole triazine complex refers to an organic metal complex composed of a triazine ring and an imidazole group, which can be prepared by the complexation reaction of a triazine derivative and a metal salt in a solvent. This substance can form a stable three-dimensional cross-linked network structure under high temperature conditions and inhibit the thermal decomposition of the colloid. 2-Ethyl-4-methylimidazole refers to an imidazole compound containing ethyl and methyl substituents, which can be prepared by the condensation reaction of methacrylate and ethylamine under acidic conditions. This substance can effectively catalyze the ring-opening reaction of epoxy groups under low temperature conditions and reduce the curing temperature threshold.

[0048] Specifically, the diaminoimidazole triazine complex forms a thermally stable structure with the epoxy resin through a metal coordination bond, and preferentially constructs a high-temperature resistant skeleton network during the curing process; 2-ethyl-4-methylimidazole activates the initial stage of the curing reaction in the range of 100°C-170°C, and reduces the reaction activation energy through a proton transfer mechanism. The two accelerators form a staged action mechanism in the curing system: imidazole accelerators achieve rapid curing and molding under low temperature conditions, and the triazine complex maintains the stability of the cross-linked network during subsequent high-temperature service. In an acid-base corrosive environment, these two substances themselves do not contain easily hydrolyzed groups, and the cross-linked structure formed can effectively block the penetration of corrosive media.

[0049] Compared with the existing technology, traditional epoxy adhesive accelerators mostly use a single imidazole substance, which can achieve low-temperature curing but cannot guarantee high-temperature stability; or the use of high-temperature accelerators leads to too high a curing temperature. This solution uses the synergistic effect of two types of accelerators to construct a chemical cross-linking system with a high thermal decomposition temperature while maintaining low-temperature curing characteristics.

[0050] Through the above technical solution, the present application realizes the full cross-linking reaction of epoxy structural adhesive under low temperature curing conditions of 100℃-170℃, and ensures that the cured colloid maintains structural integrity in a high temperature environment of 500℃-700℃. Under long-term immersion conditions of 5% acetic acid and 1% sodium hydroxide solution, no obvious swelling or depolymerization occurs at the interface of the adhesive layer, and the shear strength retention rate meets the design requirements.

[0051] The present application further proposes that the reinforcing filler is one or more of silicon micropowder, aluminum hydroxide, aluminum oxide, quartz powder, mica powder, and kaolin.

[0052] Among them, silicon micropowder refers to micron-sized particles composed of silicon dioxide, which can be realized by fused quartz powder or crystalline silicon micropowder. Its high heat resistance can reduce solidification shrinkage and maintain structural stability at high temperatures. Aluminum hydroxide refers to an inorganic compound with trihydrate aluminum oxide as the main component, which can be realized by calcined or precipitated aluminum hydroxide. The endothermic effect generated by its thermal decomposition can delay high-temperature degradation. Alumina refers to α-phase aluminum oxide powder, which can be realized by spherical or flaky aluminum oxide. Its chemical inertness can enhance its tolerance to acid and alkali media. Quartz powder refers to high-purity silicon dioxide powder, which can be realized by fused quartz crushed powder. Its high hardness can improve the wear resistance of the adhesive layer. Mica powder refers to layered silicate mineral powder, which can be realized by exfoliated powder of muscovite or phlogopite. Its lamellar structure can block the penetration path of corrosive media. Kaolin refers to a clay mineral with kaolinite as the main component, which can be specifically achieved by calcining modified kaolin, and its aluminosilicate component can promote interfacial bonding with the ceramic substrate.

[0053] Specifically, when a combination of silicon micropowder and alumina is introduced into an epoxy resin matrix, the thermal expansion coefficient of silicon micropowder and the chemical stability of alumina complement each other. The former inhibits crack propagation caused by high-temperature thermal stress, and the latter reduces the erosion rate of the resin matrix by acidic media. When used in conjunction with mica powder, its two-dimensional flaky structure is oriented along the shear direction during the curing process, forming a physical barrier layer to slow down the diffusion of corrosive media into the adhesive layer. The introduction of kaolin forms hydrogen bonds with the ceramic substrate through the surface hydroxyl groups, enhancing the interfacial bonding strength. The combination of this filler system achieves dual performance improvements in high-temperature thermal stability and chemical resistance through the synergistic effect between the components while maintaining the low-temperature curing process window.

[0054] Compared with the existing technology, traditional epoxy adhesive reinforcing fillers mostly use single calcium carbonate or talcum powder, which is easy to decompose at high temperatures above 500°C, resulting in a sudden drop in strength, and cannot effectively resist the alternating acid-base corrosion environment. This solution uses a composite of silicon micropowder and alumina to form a stable silicon-aluminum network structure at high temperature. Compared with the calcium carbonate filler system, the thermal decomposition temperature is increased by about 200°C. The introduction of mica powder replaces traditional glass fiber fillers to avoid the anisotropy problem caused by fiber orientation, and at the same time reduces the penetration rate of corrosive media to less than one-fifth of the original level through interlayer barrier effect.

[0055] Through the above technical solution, the present application enables the epoxy structural adhesive to maintain more than 90% of the initial shear strength after being subjected to high temperature treatment at 500°C for 24 hours, and the strength attenuation is controlled within 5% after continuous immersion in 5% acetic acid and 1% sodium hydroxide solution for 7 days, while ensuring complete cross-linking reaction under low temperature curing conditions at 100°C. The particle size distribution of the filler is controlled in the range of 1-20μm, and the micropores of the resin matrix are effectively filled through multi-scale particle grading, so that the porosity of the cured adhesive layer is less than 0.5%.

[0056] The present application further proposes that the reinforcing agent is one or more of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0057] Among them, γ-aminopropyltriethoxysilane refers to a silane coupling agent containing amino and ethoxy groups, which can be specifically realized by using KH-550 type silane coupling agent. The amino group can form hydrogen bonds with epoxy resin, and the ethoxy group can condense with the hydroxyl group on the surface of the inorganic filler after hydrolysis. Among them, γ-(2,3-epoxypropoxy)propyltrimethoxysilane refers to a silane coupling agent containing epoxy groups, which can be specifically realized by using KH-560 type silane coupling agent. The epoxy group can undergo a ring-opening reaction with the amine group in the curing agent to form a chemical bonding network. Among them, γ-methacryloxypropyltrimethoxysilane refers to a silane coupling agent containing double bonds, which can be specifically realized by using KH-570 type silane coupling agent. The double bond structure can participate in free radical reactions during the curing process to enhance the covalent bonding between the filler and the resin.

[0058] Specifically, the reinforcing agent achieves interface enhancement through different active groups. Aminosilane enhances the physical bonding between the resin and the filler through hydrogen bonding, epoxysilane increases the interface crosslinking density through chemical crosslinking, and methacryloxysilane forms covalent bonds through free radical reactions. When the three work together, a dense coupling layer can be formed on the surface of the filler, reducing the penetration path of the corrosive medium and improving the interface bonding stability at high temperatures.

[0059] In some specific embodiments, the reinforcing agent is mixed with the silicon micropowder in a mass ratio of 1:1:1 to perform surface treatment, and the interface debonding rate between the treated silicon micropowder and the epoxy resin is reduced under high temperature shear conditions. In another embodiment, γ-aminopropyltriethoxysilane is used alone for aluminum hydroxide filler treatment, and during the curing process, the amino group reacts with the epoxy group to form a cross-linked network.

[0060] Compared with the existing technology, conventional silane coupling agents rely only on a single active group to achieve physical or chemical bonding, and cannot maintain interface stability in high-temperature corrosion environments. This solution uses the synergistic effect of multiple types of active groups to form multiple bonding mechanisms between fillers and resins, and can still maintain interface integrity under high-temperature thermal stress and acid-base corrosion conditions.

[0061] Through the above technical scheme, the present application solves the problems of reduced corrosion resistance and adhesion caused by insufficient interface bonding between filler and resin, so that the epoxy structural adhesive can still maintain stable shear strength performance after long-term use in high temperature environments above 500°C and acid and alkali corrosive media, thereby meeting the interface reliability requirements of ceramic substrate packaging.

[0062] The present application further proposes a method for preparing an ultra-high temperature corrosion-resistant epoxy structural adhesive that can be cured at low temperature, comprising dispersing a multifunctional resin, a chain extender, a curing agent, and a color paste at high speed at room temperature, stirring at a speed of 1200 r / min for 2 hours, and evacuating the mixture while dispersing to a vacuum degree of -100 kPa, and then continuing to add a reinforcing filler for dispersion, stirring at a speed of 1000 r / min for 30 minutes, continuing to add an accelerator and dispersing and stirring at a speed of 1000 r / min for 30 minutes, and evacuating the mixture while dispersing to a vacuum degree of -100 kPa, and finally adding a reinforcing treatment agent, stirring at a speed of 1000 r / min for 30 minutes, and evacuating the mixture while dispersing to a vacuum degree of -100 kPa.

[0063] Among them, multifunctional resin refers to a resin compound containing more than three epoxy groups, such as triglycidyl para-aminophenol or tetraglycidylamine, which forms a three-dimensional network structure through multifunctional cross-linking, and can improve the thermal stability of the colloid at high temperature. Among them, chain extenders refer to compounds that can react with epoxy groups and extend the molecular chain, such as styrene-methacrylate glycidyl ester, which enhances the toughness of the colloid and adjusts the curing rate through chain extension. Among them, vacuum treatment refers to the operation of continuously evacuating to -100kpa during the mixing process, which can eliminate bubbles and volatiles in the mixture, avoid stress concentration and structural damage caused by pores at high temperatures, and reduce performance degradation caused by component volatilization during storage. Among them, adding reinforcing fillers and reinforcing treatment agents in stages refers to the introduction of inorganic fillers and surface treatment agents in sequence after the initial mixing of the resin matrix, achieving uniform distribution of fillers in the matrix through step-by-step dispersion, and using treatment agents to improve the interface bonding strength between fillers and resins, thereby improving the corrosion resistance and mechanical strength of the colloid.

[0064] Specifically, during the preparation process, high-speed dispersion and vacuum treatment are first used to fully react the resin, chain extender and curing agent to form a pre-crosslinked network, while removing bubbles to ensure the density of the structure after curing. The reinforcing filler is added in stages at a medium speed to avoid filler agglomeration due to excessive shear force, thereby ensuring that the filler is evenly dispersed to enhance the colloid's resistance to thermal stress. The accelerator is introduced after the filler is dispersed, and the reaction rate is controlled to avoid local excessive cross-linking and maintain the storage stability of the colloid. The reinforcing treatment agent is added in the final stage, and vacuum stirring is used to fully coat the filler surface, strengthen the chemical bonding between the filler and the resin, and thereby improve the tolerance of the colloid in acidic and alkaline environments. The unified control of the vacuum degree in each step effectively reduces the residual volatile substances, so that the colloid maintains component stability when stored at room temperature, and can be stably stored for one week at room temperature of 25°C.

[0065] Compared with the existing technology, the traditional epoxy adhesive preparation process often adopts a one-step mixing method, which leads to uneven dispersion of fillers or insufficient interfacial bonding strength, and is prone to cracking or debonding at high temperatures. In the existing technology, vacuum degassing is usually only implemented in the final stage, and it is impossible to completely eliminate the microbubbles generated during the mixing process, which affects the high-temperature performance of the colloid. In addition, some processes do not control the reaction rate in stages, resulting in an excessive degree of pre-crosslinking or component volatilization during storage, making it difficult to balance low-temperature curing and high-temperature stability.

[0066] Through the above technical scheme, the present application realizes the formation of a high cross-linking density and defect-free epoxy network structure under low-temperature curing conditions, so that the colloid can still withstand a high temperature environment of 500°C-700°C after curing at 100°C-170°C. The synergistic effect of the step-by-step mixing process and continuous vacuum treatment not only ensures the uniform dispersion of the filler and interface optimization, but also avoids the stress concentration problem caused by residual bubbles, thereby maintaining stable mechanical strength of the colloid in an acid-base corrosive environment. The staged control of the reaction rate during the preparation process effectively suppresses the volatilization of components and the pre-cross-linking reaction, so that the colloid maintains stable rheological properties during storage, meeting the strict requirements of industrial production for storage stability.

[0067] Recipe Number Multifunctional resin (parts) Chain extender (parts) Curing agent (parts) Accelerator (parts) Reinforcing filler (parts) Reinforcement agent (parts) Color paste (parts) Recipe 1 Triglycidyl p-aminophenol 100 Styrene-glycidyl methacrylate 10 2-Ethyl-4-methylimidazole 5 2-Ethyl-4-methylimidazole 3, diaminoimidazole triazine complex 2 Silica powder 2 γ-Aminopropyltriethoxysilane 1 Black color paste 1 Recipe 2 Phenolic resin 100 Phosphite 15 Dicyandiamide 15 2-Ethyl-4-methylimidazole 4, diaminoimidazole triazine complex 3 Aluminum hydroxide 5 γ-(2,3-Epoxypropyl)propyltrimethoxysilane 2 Black color paste 3 Recipe 3 Tetraglycidylamine 100 Dioxazoline 20 Methyltetrahydrophthalic anhydride 30 2-Ethyl-4-methylimidazole 5, diaminoimidazole triazine complex 5 Alumina 10 γ-Methacryloyloxypropyltrimethoxysilane 5 Black color paste 4 Recipe 4 Naphthol resin 100 Glycidyl Methacrylate 12 1-Cyano-2-ethyl-4-methylimidazole 10 2-Ethyl-4-methylimidazole 3, diaminoimidazole triazine complex 7 Quartz powder 6 γ-Aminopropyltriethoxysilane 3 Green Color Paste 3 Recipe 5 Tetracyclyl-4,4'-diaminodiphenylmethane 100 3,3'-Diethyl 4,4'-diaminodiphenylmethane 18 Methyl Nadic Anhydride 25 2-Ethyl-4-methylimidazole 2, diaminoimidazole triazine complex 3 Mica powder 8 γ-(2,3-Epoxypropyl)propyltrimethoxysilane4 Black color paste 4 Recipe 6 Triglycidyl p-aminophenol 50+phenolic resin 50 Glycidyl methacrylate 13 2-phenylimidazole 8 2-Ethyl-4-methylimidazole 2, diaminoimidazole triazine complex 3 Kaolin 3 γ-Aminopropyltriethoxysilane 2 Purple color paste 2 Recipe 7 Tetraglycidylamine 70+naphthol resin 30 Bisoxazoline 16 1,3-Diphenyl-2-methylimidazole 12 2-Ethyl-4-methylimidazole 2, diaminoimidazole triazine complex 3 Silica powder 7 γ-Methacryloyloxypropyltrimethoxysilane 3 Orange color paste 3 Recipe 8 Phenolic resin 60 + tetraepoxypropyl-4,4'-diaminodiphenylmethane 40 3,3'-Diethyl 4,4'-diaminodiphenylmethane 19 Methyl Nadic Anhydride 22 2-Ethyl-4-methylimidazole 1, diaminoimidazole triazine complex 5 Alumina 5 γ-(2,3-Epoxypropyl)propyltrimethoxysilane4 Black color paste 4 Recipe 9 Triglycidyl p-aminophenol 40 + tetraglycidylamine 30 + naphthol resin 30 Styrene-glycidyl methacrylate 11 Dicyandiamide 18 2-Ethyl-4-methylimidazole 5, diaminoimidazole triazine complex 3 Quartz powder 4 γ-Aminopropyltriethoxysilane 3 Black color paste 3 Recipe 10 Phenolic resin 30 + tetraepoxypropyl-4,4'-diaminodiphenylmethane 70 Phosphite 17 Methyltetrahydrophthalic anhydride 28 2-Ethyl-4-methylimidazole 7, diaminoimidazole triazine complex 2 Mica powder 6 γ-Methacryloyloxypropyltrimethoxysilane 5 Black color paste 5 In order to verify the effectiveness of the formulation method of the present invention, the key index experiments are as follows: Recipe Number Shear strength under standard conditions Soak in 5% acid solution for 7 days Soak in 1% alkaline solution for 7 days 500℃ muffle furnace 24h 700℃ muffle furnace for 5 minutes Soak in toluene solution for 7 days Recipe 1 15.5 14.8 14.5 4.5 0.6 10 Recipe 2 14.5 14 13.6 4 0.5 8.5 Recipe 3 16 15.36 15 5 0.7 9.5 Recipe 4 15 14.4 14 4.2 0.6 9 Recipe 5 15.2 14.7 14.2 4.7 0.65 9.2 Recipe 6 14.8 14.3 13.9 4.1 0.55 8.8 Recipe 7 15.6 15.1 14.6 4.6 0.6 9.3 Recipe 8 15.2 14.7 13.9 4.3 0.58 9 Recipe 9 15 14.5 13.8 4.2 0.56 8.9 Recipe 10 15.4 14.7 14.1 3.5 0.52 9.1 The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive, characterized in that: The invention comprises an epoxy structural adhesive with the following weight proportions of components: 100 parts of multifunctional resin, 10-20 parts of chain extender, 5-30 parts of curing agent, 1-10 parts of accelerator, 2-10 parts of reinforcing filler, 1-5 parts of reinforcing treatment agent and 1-5 parts of color paste. The epoxy structural adhesive is used to bond and fix the chip to the ceramic substrate. The curing temperature of the epoxy structural adhesive is 100°C-170°C and the maximum temperature resistance range is 500°C-700°C.

2. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The epoxy structural adhesive is a single-component structural adhesive with a curing temperature of 100° C.-170° C. for 4 hours and a shear strength of 14-16 MPa on an aluminum substrate.

3. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 2, characterized in that: The shear strength of the epoxy structural adhesive is reduced within 5% after being immersed in a 5% acetic acid solution for 7 days; the shear strength of the epoxy structural adhesive is reduced within 10% after being immersed in a 1% sodium hydroxide solution for 7 days.

4. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 2, characterized in that: The epoxy structural adhesive has effective shear strength of 0.5-5 MPa after being kept in a muffle furnace at 500° C. for 24 hours or in a muffle furnace at 700° C. for 5 minutes.

5. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The multifunctional resin is one or more of triglycidyl p-aminophenol, phenolic resin, tetraglycidylamine, naphthol resin, and tetraepoxypropyl-4,4'-diaminodiphenylmethane.

6. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The chain extender is one or more of styrene-glycidyl methacrylate, phosphite, dioxazoline, glycidyl methacrylate, and 3,3'-diethyl 4,4'-diaminodiphenylmethane.

7. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The accelerator is a diaminoimidazole triazine complex and 2-ethyl-4-methylimidazole.

8. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The reinforcing filler is one or more of silicon micropowder, aluminum hydroxide, aluminum oxide, quartz powder, mica powder and kaolin.

9. The low temperature curable ultra-high temperature corrosion resistant epoxy structural adhesive according to claim 1, characterized in that: The reinforcing agent is one or more of γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropyloxy)propyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

10. A method for preparing a low-temperature curable ultra-high temperature corrosion-resistant epoxy structural adhesive according to any one of claims 1 to 9, comprising the following steps: dispersing a multifunctional resin, a chain extender, a curing agent, and a color paste at high speed at room temperature, stirring at a speed of 1200 r / min for 2 hours, and evacuating while dispersing to a vacuum degree of -100 kPa, and then continuing to add reinforcing filler for dispersion, stirring at a speed of 1000 r / min for 30 minutes, continuing to add accelerator and dispersing and stirring at a speed of 1000 r / min for 30 minutes, and evacuating while dispersing to a vacuum degree of -100 kPa, and finally adding a reinforcing treatment agent, stirring at a speed of 1000 r / min for 30 minutes, and evacuating while dispersing to a vacuum degree of -100 kPa.