Electrolytic adhesive tape for electronic components and method for producing the same

Abstract

This application relates to the field of pressure-sensitive adhesive materials, and discloses an electrolytic adhesive tape for electronic components and its preparation method. The adhesive tape includes an insulating substrate and a pressure-sensitive adhesive layer coated on its surface. The pressure-sensitive adhesive layer is mainly composed of an acrylate-based copolymer resin, combined with an acylhydrazine-based dynamic crosslinking agent and a wetting and leveling agent. The matrix resin is a linear random copolymer, obtained by copolymerizing soft and hard monomers with functional acrylate monomers containing β-diketone and oxazoline groups. The preparation method includes pretreatment of the insulating substrate functionalization, matrix resin synthesis, pressure-sensitive adhesive preparation, coating and curing, and finished product preparation. This adhesive tape can be used for insulating and structurally fixing electrolyte-containing components such as lithium-ion batteries, aluminum electrolytic capacitors, and supercapacitors. It combines excellent room-temperature pressure-sensitive mounting performance with long-term adhesion stability in electrolyte environments, fundamentally avoiding the problem of small molecule additive migration and precipitation, exhibiting high reliability and suitability for automated large-scale production.

Description

Technical Field

[0001] This application relates to the field of pressure-sensitive adhesive materials technology, and more specifically, it relates to an electrolytic adhesive tape for electronic components and a method for preparing the same. Background Technology

[0002] Electrolytic adhesive tape for electronic components is a key material for electrolyte-containing components such as aluminum electrolytic capacitors, lithium-ion batteries, and supercapacitors. It is mainly used for insulating and covering electrode tabs, protecting electrode edges, and bonding and fixing internal structures. Its performance directly affects the safety and long-term reliability of the components. With industrial upgrading, the industry has placed increasingly higher demands on this tape to simultaneously meet the pressure-sensitive properties required for automated placement and its long-term stability in electrolyte environments.

[0003] Currently, conventional electrolytic adhesive tapes in the industry mostly use an acrylic matrix combined with a permanent crosslinking agent, and also require the addition of small molecule functional additives such as tackifying resins and antioxidants. The permanent crosslinking system struggles to balance room-temperature pressure-sensitive fit with adhesive stability after electrolyte immersion, easily leading to insufficient initial adhesion or swelling and delamination. Furthermore, the added small molecule additives are prone to migration and precipitation, contaminating the electrolyte and exacerbating adhesive layer failure. How to fundamentally resolve the inherent contradiction between pressure-sensitive fit and long-term weather resistance, while simultaneously avoiding the reliability risks posed by small molecule additives, is a core technical problem urgently needing to be solved in this field. Summary of the Invention

[0004] To address the core technical issues of existing electrolytic adhesive tapes, such as difficulty in achieving both room-temperature pressure-sensitive mounting performance and long-term adhesion stability under electrolyte conditions, and the easy migration and precipitation of small molecule additives, this application provides an electrolytic adhesive tape for electronic components and its preparation method.

[0005] In a first aspect, this application provides an electrolytic adhesive tape for electronic components, employing the following technical solution. An electrolytic adhesive tape for electronic components includes an insulating substrate and a pressure-sensitive adhesive layer coated on the surface of the insulating substrate. The pressure-sensitive adhesive layer comprises, by weight, the following components: 100 parts of acrylate-based copolymer resin; 0.5-3 parts of dynamic crosslinking agent, wherein the dynamic crosslinking agent is an organic compound containing two or more hydrazide groups; and 0.1-0.5 parts of wetting and leveling agent. The acrylate-based copolymer resin is a linear random copolymer, and its polymeric monomers include 70-85 parts of soft monomers, 10-20 parts of hard monomers, 3-10 parts of acrylate monomers containing β-diketone structures, and 0.5-3 parts of acrylate monomers containing oxazoline groups.

[0006] By adopting the above technical solution, acrylate monomers containing β-diketone structures, acrylate monomers containing oxazoline groups, and soft and hard monomers are randomly copolymerized, which can stably graft functional groups onto the acrylate polymer backbone. Combined with bifunctional acylhydrazine dynamic crosslinking agents, a uniform and controllable reversible dynamic crosslinking network is formed. The soft monomers provide the adhesive layer with good initial tack, interfacial wettability, and low-temperature flexibility, while the hard monomers provide the adhesive layer with basic cohesive strength, heat resistance, and deformation resistance. The β-diketone structure can undergo a controlled reaction with the hydrazone group at room temperature to form dynamic hydrazone bonds, ensuring the pressure-sensitive mounting performance of the adhesive layer at room temperature and undergoing further crosslinking reactions when in contact with water and metal ions in the electrolyte, achieving in-situ reinforcement of the adhesive layer's cohesive strength and dielectric resistance. The oxazoline group can undergo a ring-opening reaction with carboxylic acids generated during electrolyte aging, eliminating the corrosion of the adhesive layer structure and the internal components by acidic substances and forming additional crosslinking points, further enhancing the adhesive layer's dielectric stability and long-term service performance. All core properties are integrated into the polymer backbone through the structural design of the comonomers, eliminating the need for additional small molecule functional additives and fundamentally avoiding the risk of small molecule additive migration and precipitation. This achieves a synergistic balance between the room-temperature pressure-sensitive mounting performance of the adhesive layer and its long-term weather resistance stability under electrolyte conditions.

[0007] Preferably, the insulating substrate is selected from any one of polyethylene terephthalate film, polyimide film, or polypropylene film, and the thickness of the insulating substrate is 12 μm to 50 μm; the surface of the insulating substrate to be coated is pretreated with a silane coupling agent containing a β-diketone structure, and the surface of the insulating substrate has β-diketone functional groups connected by chemical bonds.

[0008] By adopting the above technical solution, the selected substrates are all commonly used insulating support materials in the field of electronic components, which can be adapted to the application requirements of different temperature resistance and thickness. The substrate is pretreated by a silane coupling agent containing a β-diketone structure. One end of the silane coupling agent can form a stable silicon-oxygen covalent bond with the hydroxyl groups generated by the activation of the substrate surface, and the other end can introduce β-diketone functional groups that are homologous to the adhesive layer system. This enables the insulating substrate and the pressure-sensitive adhesive layer to form an integrated dynamic cross-linked network, rather than a simple physical adsorption bond. This effectively prevents the electrolyte from penetrating to the interface between the substrate and the adhesive layer, avoiding failure problems such as interface debonding and edge warping during long-term service, and significantly improving the long-term stability of the interface bonding of the adhesive tape in the electrolyte environment.

[0009] Preferably, the dry adhesive thickness of the pressure-sensitive adhesive layer is 5 μm to 30 μm; the dynamic crosslinking agent is selected from one or a combination of two of diacylhydrazide or sebacate diacylhydrazide; the wetting and leveling agent is a polyether-modified acrylate leveling agent or a polyester-modified acrylate leveling agent, and its mass fraction in the pressure-sensitive adhesive layer does not exceed 0.5%.

[0010] By adopting the above technical solutions, the limited adhesive layer thickness range can cover the application requirements of different bonding and protection scenarios for electronic components, ensuring the adaptability of the adhesive tape under different working conditions. The selected hydrazide crosslinking agent has hydrazide groups at both ends of the molecule that can react efficiently with the β-diketone structure on the polymer backbone. The hydrazide monomers with different carbon chain lengths can flexibly control the density of the crosslinking network and the toughness of the adhesive layer to adapt to different performance requirements. The selected acrylate leveling agent is a non-migrating additive that can effectively improve the coating spreadability and substrate wettability of the adhesive, reduce defects such as coating pinholes and craters, and will not migrate within the adhesive layer, thus not affecting the cohesive strength and long-term service performance of the adhesive layer. The limitation of its mass fraction can avoid the negative impact of excessive addition of leveling agent on the adhesive layer's bonding performance and cohesive strength.

[0011] Preferably, the soft monomer is selected from one or a combination of two of isooctyl acrylate and butyl acrylate; the hard monomer is selected from one or a combination of two of methyl methacrylate and methyl acrylate; the acrylate monomer containing a β-diketone structure is ethyl acetoacetate methacrylate; the acrylate monomer containing an oxazoline group is 2-isopropenyl-2-oxazoline; and the pressure-sensitive adhesive layer does not contain independently added tackifying resin, antioxidant, metal passivating agent, or media-resistant additive.

[0012] By adopting the above technical solution, the selected acrylate monomers exhibit good matching of copolymerization competition rates and strong controllability of free radical copolymerization reactions, enabling the stable preparation of linear random copolymers with uniform structure and suitable molecular weight distribution. Among them, the soft monomers possess lower glass transition temperatures, imparting excellent pressure-sensitive properties and interfacial adhesion to the adhesive layer; the hard monomers possess higher glass transition temperatures, allowing precise control of the overall glass transition temperature of the adhesive layer and balancing initial tack and holding power. The selected functional monomers can efficiently introduce target functional groups into the polymer backbone, ensuring uniform distribution of functional groups on the polymer chain and achieving stable performance. All core properties are achieved through the structural design of the polymer backbone, eliminating the need for independently adding tackifying resins, antioxidants, and other small molecule functional additives. This completely eliminates the industry pain point of small molecule additives migrating and precipitating in long-term high-temperature and electrolyte immersion environments, contaminating the electrolyte system, and compromising the adhesive layer's bonding stability, further improving the product's long-term service reliability.

[0013] Secondly, this application provides a method for preparing electrolytic adhesive tape for electronic components, using the following technical solution: A method for preparing an electrolytic adhesive tape for electronic components includes the following steps: S1. Pretreatment for directional functionalization of insulating substrate: The surface of the insulating substrate to be coated is subjected to corona treatment or plasma treatment, and then a pretreatment working solution prepared with a silane coupling agent containing a β-diketone structure is applied to the treated surface. After drying, a functionalized substrate with β-diketone functional groups on the surface is obtained. S2. Synthesis of acrylate-based copolymer resin: Soft monomers, hard monomers, acrylate monomers containing β-diketone structures, and acrylate monomers containing oxazoline groups are added to a mixed solvent and stirred until homogeneous to obtain a monomer mixture; an initiator is added to the monomer mixture, and after deoxygenation treatment, the mixture is heated to the polymerization temperature to carry out a free radical copolymerization reaction. After the reaction is completed, the mixture is cooled and discharged to obtain an acrylate-based copolymer resin solution. S3. Preparation of adaptive crosslinking pressure-sensitive adhesive: Add dynamic crosslinking agent and wetting and leveling agent to the acrylate-based copolymer resin solution and stir to mix; add pH adjuster to adjust the pH value of the system to a predetermined range, continue stirring, let stand to degas, and obtain pressure-sensitive adhesive; S4. Coating, curing and finished product preparation: The pressure-sensitive adhesive liquid is coated on the pretreated surface of the functionalized substrate, and the thickness of the pressure-sensitive adhesive layer is controlled after drying; the solvent is removed by drying treatment, the release film is attached, and the tape is wound up; the tape is cured in a curing environment to obtain the finished electrolytic adhesive tape for electronic components.

[0014] By adopting the above technical solution and through a continuous and controllable preparation process, the large-scale production of adhesive tape can be stably achieved. The processes are seamlessly connected and can be adapted to industry-standard coating production equipment. First, the surface functionalization modification of the insulating substrate is completed, laying the foundation for the integrated bonding of the substrate and the adhesive layer. Simultaneously, a matrix resin with functional groups is prepared through free radical copolymerization, precisely controlling the structure and properties of the polymer. Then, the crosslinking reaction process is regulated through the adhesive formulation process to lock in the initial properties of the adhesive layer. Finally, the film formation and crosslinking of the adhesive layer are completed through coating, drying, and curing processes. The entire process parameters are highly controllable, ensuring stable batch consistency of product performance and fully achieving the performance design goals of the formulation system.

[0015] Preferably, in step S1, the pretreatment working solution comprises, by mass, 0.5-2 parts of a silane coupling agent containing a β-diketone structure, 80-90 parts of anhydrous ethanol, and 10-19.5 parts of deionized water; the thickness of the wet film coated with the pretreatment working solution is 5 μm to 10 μm; the drying temperature is 80°C to 100°C, and the drying time is 3 to 5 minutes.

[0016] By employing the above technical solutions, the composition ratio of the pretreatment working solution is limited. The mixture of anhydrous ethanol and deionized water allows for precise control of the hydrolysis rate of the silane coupling agent, avoiding self-polymerization failure caused by excessively rapid hydrolysis or insufficient grafting reaction due to excessively slow hydrolysis. Limiting the content of the silane coupling agent ensures the formation of a uniform and dense functional group grafted layer on the substrate surface, avoiding poor grafting effect due to insufficient concentration or uneven coating and decreased adhesion due to excessive concentration. Limiting the wet film thickness and drying parameters ensures sufficient solvent evaporation and allows the silane coupling agent to fully complete the condensation reaction with the active groups on the substrate surface, forming stable covalent bonds and ensuring stable and controllable functionalization modification of the substrate surface.

[0017] Preferably, in step S2, the mixed solvent is a mixture of ethyl acetate and anhydrous ethanol, with a mass ratio of ethyl acetate to anhydrous ethanol of 2.5:1 to 3.5:1; the initiator is azobisisobutyronitrile, and the amount of initiator added is 0.1% to 0.3% of the total mass of the monomers; the deoxygenation treatment is performed by purging with nitrogen for 20 to 40 minutes; the polymerization temperature is 65°C to 75°C, and the reaction time is 4 to 6 hours; the solid content of the acrylate-based copolymer resin solution is 30% to 40%.

[0018] By adopting the above technical solutions, the selected mixed solvent system can fully dissolve various acrylate monomers and reaction products, ensuring the copolymerization reaction proceeds stably in a homogeneous system. The limited solvent ratio allows for flexible control of the system's polarity and viscosity, adapting to the polymerization rate and subsequent coating process requirements. The selection and dosage of the initiator precisely control the polymer's molecular weight and molecular weight distribution, ensuring the stability of the matrix resin's performance and avoiding insufficient monomer conversion due to too little initiator, or excessive initiator leading to too low molecular weight and insufficient cohesive strength of the adhesive layer. Nitrogen deoxygenation treatment effectively eliminates oxygen in the system, preventing its inhibitory effect on free radical polymerization and improving monomer conversion and polymer structural uniformity. Matching the polymerization temperature and reaction time achieves high monomer conversion while preparing a matrix resin solution with solid content and viscosity suitable for subsequent coating processes, avoiding performance deviations caused by incomplete or excessive reaction.

[0019] Preferably, in step S3, the stirring and mixing process of the dynamic crosslinking agent and the wetting and leveling agent is carried out by stirring at room temperature in a closed environment for 20 to 40 minutes; the pH adjuster is triethylamine or N,N-dimethylethanolamine, and the amount of pH adjuster added is 0.05% to 0.2% of the total mass of the adhesive solution; the pH value of the system is adjusted to 7.5 to 8.5; the stirring time is 10 to 20 minutes; and the standing and degassing time is 5 to 15 minutes.

[0020] By adopting the above technical solution, room-temperature closed stirring ensures uniform dispersion of each component in the resin system, while avoiding fluctuations in the solid content of the system caused by solvent evaporation, which would affect the precise control of subsequent coating thickness. The selected organic amine pH adjuster can precisely regulate the acidity or alkalinity of the system. Based on the reaction characteristics of acylhydrazone bonds, it can effectively inhibit excessive reaction of acylhydrazone bonds during the adhesive preparation stage in a weakly alkaline environment of 7.5-8.5, stabilizing and locking the initial cross-linking degree of the adhesive layer and ensuring the room-temperature pressure-sensitive bonding performance of the adhesive layer. At the same time, this type of adjuster has good volatility and can be completely removed in the subsequent drying process, leaving no residue in the adhesive layer and avoiding adverse effects on the long-term service performance of the adhesive layer. The limitation of stirring and degassing parameters ensures uniform mixing of the system, fully eliminating micro-bubbles in the adhesive solution, avoiding structural defects such as pinholes and craters in the final adhesive layer, and ensuring the integrity and performance consistency of the adhesive layer structure.

[0021] Preferably, in step S4, the drying process is carried out in a segmented oven with the oven temperature set to 80°C to 100°C and the total drying time is 5 to 10 minutes; the thickness of the pressure-sensitive adhesive layer after drying is controlled to be 5 μm to 30 μm; and the curing is carried out in an environment with a temperature of 20°C to 30°C and a relative humidity of 45% to 55% for 4 to 8 hours.

[0022] By adopting the above technical solution, segmented oven drying can achieve sequential solvent removal. First, the solvent inside the adhesive layer slowly migrates and evaporates through a steady temperature increase. Then, the residual solvent is completely removed by setting a specific temperature. This avoids coating defects such as skinning, pinholes, edge shrinkage, and sagging caused by rapid solvent evaporation. The limited temperature and time balance solvent removal efficiency and adhesive film quality. Precise control of the adhesive layer thickness ensures consistent product performance and adapts to different application scenarios. The constant temperature and humidity curing conditions allow the dynamic cross-linking reaction within the adhesive layer to complete smoothly and uniformly, forming a structurally stable dynamic cross-linking network. This replaces the industry's conventional high-temperature, long-time curing process, significantly shortening the production cycle and reducing energy consumption. At the same time, it avoids problems such as substrate thermal shrinkage and excessive cross-linking of adhesive layer properties caused by high-temperature curing, ensuring the dimensional accuracy and performance stability of the product.

[0023] Preferably, in step S1, the corona treatment or plasma treatment ensures that the dyne value of the surface of the insulating substrate to be coated is not less than 42 mN / m.

[0024] By adopting the above technical solution, the surface dyne value of the substrate can be controlled at no less than 42mN / m, which can significantly improve the surface energy of the substrate, ensure that the pretreatment working solution is evenly spread and wetted on the substrate surface, and avoid problems such as uneven coating, pinholes, and missed coating. At the same time, it provides sufficient active hydroxyl sites for the chemical bonding between the silane coupling agent and the substrate surface, ensuring the grafting effect and uniformity of functional groups on the substrate surface, and providing a foundation for the long-term stable bonding between the substrate and the adhesive layer.

[0025] In summary, this application has the following beneficial effects: 1. This application uses acrylate monomers containing β-diketone structures and acrylate monomers containing oxazoline groups for random copolymerization, and constructs an adaptive crosslinking system in conjunction with hydrazide-based dynamic crosslinking agents. At the same time, it achieves a formulation design without free small molecule functional additives, fundamentally solving the inherent industry contradiction between pressure-sensitive adhesive properties and electrolyte stability, and significantly improving the long-term bonding reliability and dimensional stability of adhesive tapes in electrolyte environments.

[0026] 2. In this application, a silane coupling agent containing a β-diketone structure is preferably used for directional functionalization pretreatment of the insulating substrate. First, the surface activity of the substrate is enhanced by surface activation, and then the β-diketone functional groups are fixed by chemical bonding. This incorporates the substrate-adhesive interface into the overall dynamic cross-linking network, effectively avoiding interface debonding and edge warping problems under long-term immersion in electrolyte, and significantly improving the long-term stability of the interface bonding. 3. The preparation method of this application uses a completely volatile organic amine pH adjuster to precisely control the pH range of the adhesive system, thereby achieving stable locking of the initial cross-linking degree of the adhesive layer. This not only ensures the initial tack performance of the adhesive tape at room temperature and its compatibility with automated application, but also reserves sufficient space for in-situ cross-linking enhancement under working conditions, thus improving the controllability of the adhesive layer's performance throughout its entire life cycle.

[0027] 4. The preparation method of this application, through precise control of free radical copolymerization process parameters and in combination with the reaction characteristics of dynamic crosslinking system, can complete the crosslinking and shaping of the adhesive layer by using a room temperature short-time curing process, which replaces the industry's conventional long-time high-temperature curing process, greatly shortens the production cycle, reduces production energy consumption, and effectively improves the performance stability between product batches. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for preparing electrolytic adhesive tape for electronic components provided in this application. Detailed Implementation

[0029] The present application will be further described in detail below with reference to embodiments and comparative examples. Unless otherwise specified, the experimental methods used below are conventional methods. Unless otherwise specified, the materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels or prepared according to literature methods.

[0030] Technical Concept: In energy storage and electronic components containing electrolytes, electrolytic adhesive tape is a key supporting material for insulation, protection, and structural fixation, and its performance directly affects the safety and lifespan of the components. Currently, most conventional electrolytic adhesive tapes in the industry use an acrylic matrix with a permanent crosslinking agent system, and additional small-molecule functional additives are required. This makes it difficult to balance room-temperature pressure-sensitive mounting performance with long-term adhesion stability in an electrolyte environment. Furthermore, the small-molecule additives are prone to migration and precipitation, contaminating the electrolyte and accelerating adhesive layer failure, thus failing to meet the requirements of high-reliability components.

[0031] To address the aforementioned issues, this solution utilizes random copolymerization of functional monomers containing β-diketone structures and oxazoline groups to integrate core performance into the polymer backbone. It also employs hydrazide-based dynamic crosslinking agents to construct an adaptive dynamic crosslinking network, and utilizes silane coupling agents containing β-diketone structures to achieve integrated crosslinking of the substrate and adhesive layer. This approach fundamentally resolves the inherent contradictions within the industry, and further optimizes the process to achieve a dual improvement in product performance and production efficiency.

[0032] Preparation Example 1: Preparation of silane coupling agents containing β-diketone structures The silane coupling agent containing a β-diketone structure prepared in this example is acetoacetylpropyltriethoxysilane. The specific preparation process is as follows: 1 mol of 3-aminopropyltriethoxysilane and 1.05 mol of ethyl acetoacetate are added to a four-necked reaction flask equipped with a mechanical stirrer, a reflux condenser, a thermometer, and a nitrogen protection port. After continuously purging dry nitrogen to remove air from the system, stirring is started and the temperature is raised to 80°C at a uniform rate. The reaction is maintained at this temperature and stirred in a sealed environment for 4 hours. During the reaction, the byproduct ethanol is continuously removed. After the reaction is completed, the system is heated to 120°C, and unreacted raw materials and residual byproducts are removed by vacuum distillation. After naturally cooling to room temperature, a colorless and transparent acetoacetylpropyltriethoxysilane product is obtained, which is the target silane coupling agent containing a β-diketone structure. The product can be directly used in the preparation of the pretreatment working solution for insulating substrates.

[0033] The following are the main raw materials and reagents used in the preparation examples, embodiments, and comparative examples, and their sources and specifications are as follows; unless otherwise specified, all reagents are commercially available analytical grade or higher products: 1. Isooctyl acrylate: CAS: 103-11-7; 2. Butyl acrylate: CAS: 141-32-2; 3. Methyl methacrylate: CAS: 80-62-6; 4. Methyl acrylate: CAS: 96-33-3; 5. Ethyl acetoacetate methacrylate: CAS: 21282-97-3, contains polymerization inhibitor; 6. 2-Isopropenyl-2-oxazoline: CAS: 1097-53-6; 7. Adipic acid dihydrazide: CAS: 1071-93-8; 8. Sebacic acid dihydrazide: CAS: 125-83-7; 9. Polyether-modified acrylate leveling agent BYK-358N: purchased from Hunan Youxin Materials Technology Co., Ltd., item number: 011120; 10. Polyester-modified acrylate leveling agent BYK-310: purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; 11. Polyether-modified acrylate leveling agent TEGOGlide 450: purchased from Shanghai Zhenlishi Network Technology Co., Ltd. 12. 3-Aminopropyltriethoxysilane: CAS: 919-30-2; 13. Ethyl acetoacetate: CAS: 141-97-9; 14. Ethyl acetate: CAS: 141-78-6; 15. Anhydrous ethanol: CAS: 64-17-5; 16. Azobisisobutyronitrile: CAS: 78-67-1; 17. Triethylamine: CAS: 121-44-8; 18. N,N-Dimethylethanolamine: CAS: 108-01-0; 19. Toluene diisocyanate trimer: CAS: 28182-81-2; 20. Antioxidant 1010: CAS: 6683-19-8; 21. Benzotriazole: CAS: 95-14-7; 22. Trimethylolpropane tris[3-(2-methylaziridinyl)]propionate: CAS: 64265-57-2; 23. Lithium hexafluorophosphate: CAS: 21324-40-7; 24. Ethylene carbonate: CAS: 96-49-1; 25. Dimethyl carbonate: CAS: 616-38-6; 26. Ethyl methyl carbonate: CAS: 623-53-0.

[0034] Example 1: This example provides an electrolytic adhesive tape for electronic components, including an insulating substrate and a pressure-sensitive adhesive layer coated on the surface of the insulating substrate.

[0035] The pressure-sensitive adhesive layer comprises the following components by weight: 100 parts of acrylate-based copolymer resin; 1.75 parts of dynamic crosslinking agent; and 0.3 parts of wetting and leveling agent.

[0036] The dynamic crosslinking agent is adipic acid dihydrazide; the wetting and leveling agent is a polyether-modified acrylate leveling agent, specifically the commercially available BYK-358N, whose mass fraction in the pressure-sensitive adhesive layer is 0.29%, not exceeding 0.5%; the pressure-sensitive adhesive layer does not contain independently added tackifying resins, antioxidants, metal passivators, or media-resistant additives.

[0037] The acrylate-based copolymer resin is a linear random copolymer. Its monomers, based on a total mass of 100 parts, include 77 parts of soft monomers, 15 parts of hard monomers, 6 parts of acrylate monomers containing β-diketone structures, and 2 parts of acrylate monomers containing oxazoline groups.

[0038] Among them, the soft monomer is isooctyl acrylate; the hard monomer is methyl methacrylate; the acrylate monomer containing a β-diketone structure is ethyl acetoacetate methacrylate; and the acrylate monomer containing an oxazoline group is 2-isopropenyl-2-oxazoline.

[0039] The insulating substrate is a polyethylene terephthalate film with a thickness of 31 μm; the surface of the insulating substrate to be coated with adhesive is pretreated with a silane coupling agent containing a β-diketone structure prepared in Preparation Example 1, and the surface of the insulating substrate has β-diketone functional groups connected by chemical bonds.

[0040] The dry adhesive thickness of the pressure-sensitive adhesive layer is 17.5 μm.

[0041] The preparation method of the above-mentioned electrolytic adhesive tape for electronic components includes the following steps: S1. Pretreatment for directional functionalization of insulating substrate: The surface of the insulating substrate to be coated is subjected to corona treatment or plasma treatment, and then a pretreatment working solution prepared with a silane coupling agent containing a β-diketone structure is applied to the treated surface. After drying, a functionalized substrate with β-diketone functional groups on the surface is obtained.

[0042] In this embodiment, the dyne value of the surface of the insulating substrate to be coated with adhesive is not less than 42 mN / m, and the dyne value is controlled at 44 mN / m. The pretreatment working solution, by weight, includes 1.25 parts of silane coupling agent containing β-diketone structure, 85 parts of anhydrous ethanol, and 13.75 parts of deionized water. The wet film thickness of the pretreatment working solution is 7.5 μm. The drying temperature is 90°C and the drying time is 4 minutes.

[0043] S2. Synthesis of acrylate-based copolymer resin: Soft monomers, hard monomers, acrylate monomers containing β-diketone structures and acrylate monomers containing oxazoline groups are added to a mixed solvent and stirred until homogeneous to obtain a monomer mixture. An initiator is added to the monomer mixture, and after deoxygenation treatment, the mixture is heated to the polymerization temperature to carry out a free radical copolymerization reaction. After the reaction is completed, the mixture is cooled and discharged to obtain an acrylate-based copolymer resin solution.

[0044] The mixed solvent is a mixture of ethyl acetate and anhydrous ethanol, with a mass ratio of ethyl acetate to anhydrous ethanol of 3:1; the initiator is azobisisobutyronitrile, and the amount of initiator added is 0.2% of the total mass of the monomers; the deoxygenation treatment is to purge with nitrogen for 30 minutes, and the reaction is carried out under a nitrogen protective atmosphere; the polymerization temperature is 70℃, and the reaction time is 5 hours; the solid content of the acrylate-based copolymer resin solution is 35%.

[0045] S3. Preparation of self-adaptive crosslinking pressure-sensitive adhesive: Add dynamic crosslinking agent and wetting and leveling agent to acrylate-based copolymer resin solution and stir to mix; add pH adjuster to adjust the pH value of the system to the predetermined range, continue stirring, let stand to degas, and obtain pressure-sensitive adhesive.

[0046] The dynamic crosslinking agent and wetting leveling agent were mixed by stirring at room temperature in a closed environment for 30 minutes; the pH adjuster was triethylamine, and the amount of pH adjuster added was 0.125% of the total mass of the adhesive; the pH value of the system was adjusted to 8.0; after the pH adjustment was completed, stirring was continued at room temperature for 15 minutes; and the standing time for degassing was 10 minutes.

[0047] S4. Coating, Curing and Finished Product Preparation: The pressure-sensitive adhesive liquid is coated onto the pretreated surface of the functionalized substrate, and the thickness of the pressure-sensitive adhesive layer is controlled after drying; the solvent is removed by drying, the release film is attached, and the tape is wound up; the tape is cured in a curing environment to obtain the finished electrolytic adhesive tape for electronic components.

[0048] The pressure-sensitive adhesive was coated using a precision coating machine; the drying process was carried out in a segmented oven with the oven temperature set at 90℃ and the total drying time being 7.5 minutes; the thickness of the pressure-sensitive adhesive layer after drying was controlled at 17.5μm; and the curing process was carried out for 6 hours in an environment with a temperature of 25℃ and a relative humidity of 50%.

[0049] Example 2: This example provides an electrolytic adhesive tape for electronic components, including an insulating substrate and a pressure-sensitive adhesive layer coated on the surface of the insulating substrate.

[0050] The pressure-sensitive adhesive layer comprises the following components by weight: 100 parts of acrylate-based copolymer resin; 0.5 parts of dynamic crosslinking agent; and 0.1 parts of wetting and leveling agent.

[0051] The dynamic crosslinking agent is sebacic acid dihydrazide; the wetting and leveling agent is a polyester-modified acrylate leveling agent, specifically the commercially available BYK-310, which has a mass fraction of 0.1% in the pressure-sensitive adhesive layer, not exceeding 0.5%; the pressure-sensitive adhesive layer does not contain independently added tackifying resins, antioxidants, metal passivators, or media-resistant additives.

[0052] The acrylate-based copolymer resin is a linear random copolymer. Its monomers, based on a total mass of 100 parts, include 85 parts of soft monomers, 11.5 parts of hard monomers, 3 parts of acrylate monomers containing β-diketone structures, and 0.5 parts of acrylate monomers containing oxazoline groups.

[0053] Among them, the soft monomer is butyl acrylate; the hard monomer is methyl acrylate; the acrylate monomer containing the β-diketone structure is ethyl acetoacetate methacrylate; and the acrylate monomer containing the oxazoline group is 2-isopropenyl-2-oxazoline.

[0054] The insulating substrate is a polypropylene film with a thickness of 12 μm; the surface of the insulating substrate to be coated with adhesive is pretreated with a silane coupling agent containing a β-diketone structure prepared in Preparation Example 1, and the surface of the insulating substrate has β-diketone functional groups connected by chemical bonds.

[0055] The dry adhesive thickness of the pressure-sensitive adhesive layer is 5μm.

[0056] The preparation method of the above-mentioned electrolytic adhesive tape for electronic components includes the following steps: S1. Pretreatment for directional functionalization of insulating substrate: The surface of the insulating substrate to be coated is subjected to corona treatment or plasma treatment, and then a pretreatment working solution prepared with a silane coupling agent containing a β-diketone structure is applied to the treated surface. After drying, a functionalized substrate with β-diketone functional groups on the surface is obtained.

[0057] In this embodiment, the dyne value of the surface of the insulating substrate to be coated with adhesive is not less than 42 mN / m, and the dyne value is controlled at 42 mN / m. The pretreatment working solution, by weight, includes 0.5 parts of silane coupling agent containing β-diketone structure, 90 parts of anhydrous ethanol, and 9.5 parts of deionized water. The wet film thickness of the pretreatment working solution is 5 μm. The drying temperature is 80°C and the drying time is 3 minutes.

[0058] S2. Synthesis of acrylate-based copolymer resin: Soft monomers, hard monomers, acrylate monomers containing β-diketone structures and acrylate monomers containing oxazoline groups are added to a mixed solvent and stirred until homogeneous to obtain a monomer mixture. An initiator is added to the monomer mixture, and after deoxygenation treatment, the mixture is heated to the polymerization temperature to carry out a free radical copolymerization reaction. After the reaction is completed, the mixture is cooled and discharged to obtain an acrylate-based copolymer resin solution.

[0059] The mixed solvent is a mixture of ethyl acetate and anhydrous ethanol, with a mass ratio of ethyl acetate to anhydrous ethanol of 2.5:1; the initiator is azobisisobutyronitrile, and the amount of initiator added is 0.1% of the total mass of the monomers; the deoxygenation treatment is to purge with nitrogen for 20 minutes, and the reaction is carried out under a nitrogen protective atmosphere; the polymerization temperature is 65℃, and the reaction time is 4 hours; the solid content of the acrylate-based copolymer resin solution is 30%.

[0060] S3. Preparation of self-adaptive crosslinking pressure-sensitive adhesive: Add dynamic crosslinking agent and wetting and leveling agent to acrylate-based copolymer resin solution and stir to mix; add pH adjuster to adjust the pH value of the system to the predetermined range, continue stirring, let stand to degas, and obtain pressure-sensitive adhesive.

[0061] The dynamic crosslinking agent and wetting leveling agent were mixed by stirring at room temperature in a closed environment for 20 minutes; the pH adjuster was N,N-dimethylethanolamine, and the amount of pH adjuster added was 0.05% of the total mass of the adhesive; the pH value of the system was adjusted to 7.5; after the pH adjustment was completed, stirring was continued at room temperature for 10 minutes; and the standing time for degassing was 5 minutes.

[0062] S4. Coating, Curing and Finished Product Preparation: The pressure-sensitive adhesive liquid is coated onto the pretreated surface of the functionalized substrate, and the thickness of the pressure-sensitive adhesive layer is controlled after drying; the solvent is removed by drying, the release film is attached, and the tape is wound up; the tape is cured in a curing environment to obtain the finished electrolytic adhesive tape for electronic components.

[0063] The pressure-sensitive adhesive was coated using a precision coating machine; the drying process was carried out in a segmented oven with the oven temperature set at 80℃ and the total drying time being 5 minutes; the thickness of the pressure-sensitive adhesive layer after drying was controlled at 5μm; and the curing was carried out for 4 hours in an environment with a temperature of 20℃ and a relative humidity of 45%.

[0064] Example 3: This example provides an electrolytic adhesive tape for electronic components, including an insulating substrate and a pressure-sensitive adhesive layer coated on the surface of the insulating substrate.

[0065] The pressure-sensitive adhesive layer comprises the following components by weight: 100 parts of acrylate-based copolymer resin; 3 parts of dynamic crosslinking agent; and 0.5 parts of wetting and leveling agent.

[0066] The dynamic crosslinking agent is a combination of adipate dihydrazide and sebacic dihydrazide in a mass ratio of 1:1; the wetting and leveling agent is a polyether-modified acrylate leveling agent, specifically the commercially available TEGOGlide450, with a mass fraction of 0.48% in the pressure-sensitive adhesive layer, not exceeding 0.5%; the pressure-sensitive adhesive layer does not contain independently added tackifying resins, antioxidants, metal passivators, or media-resistant additives.

[0067] The acrylate-based copolymer resin is a linear random copolymer. Its polymer monomers, based on a total mass of 100 parts, include 70 parts of soft monomers, 17 parts of hard monomers, 10 parts of acrylate monomers containing β-diketone structures, and 3 parts of acrylate monomers containing oxazoline groups.

[0068] Among them, the soft monomer is isooctyl acrylate; the hard monomer is methyl methacrylate; the acrylate monomer containing a β-diketone structure is ethyl acetoacetate methacrylate; and the acrylate monomer containing an oxazoline group is 2-isopropenyl-2-oxazoline.

[0069] The insulating substrate is a polyimide film with a thickness of 50 μm; the surface of the insulating substrate to be coated with adhesive is pretreated with a silane coupling agent containing a β-diketone structure prepared in Preparation Example 1, and the surface of the insulating substrate has β-diketone functional groups connected by chemical bonds.

[0070] The dry adhesive layer has a thickness of 30 μm.

[0071] The preparation method of the above-mentioned electrolytic adhesive tape for electronic components includes the following steps: S1. Pretreatment for directional functionalization of insulating substrate: The surface of the insulating substrate to be coated is subjected to corona treatment or plasma treatment, and then a pretreatment working solution prepared with a silane coupling agent containing a β-diketone structure is applied to the treated surface. After drying, a functionalized substrate with β-diketone functional groups on the surface is obtained.

[0072] In this embodiment, the dyne value of the surface of the insulating substrate to be coated with adhesive is not less than 42 mN / m, and the dyne value is controlled at 48 mN / m. The pretreatment working solution, by weight, includes 2 parts of silane coupling agent containing β-diketone structure, 80 parts of anhydrous ethanol, and 18 parts of deionized water. The wet film thickness of the pretreatment working solution is 10 μm. The drying temperature is 100°C and the drying time is 5 minutes.

[0073] S2. Synthesis of acrylate-based copolymer resin: Soft monomers, hard monomers, acrylate monomers containing β-diketone structures and acrylate monomers containing oxazoline groups are added to a mixed solvent and stirred until homogeneous to obtain a monomer mixture. An initiator is added to the monomer mixture, and after deoxygenation treatment, the mixture is heated to the polymerization temperature to carry out a free radical copolymerization reaction. After the reaction is completed, the mixture is cooled and discharged to obtain an acrylate-based copolymer resin solution.

[0074] The mixed solvent is a mixture of ethyl acetate and anhydrous ethanol, with a mass ratio of ethyl acetate to anhydrous ethanol of 3.5:1; the initiator is azobisisobutyronitrile, and the amount of initiator added is 0.3% of the total mass of the monomers; the deoxygenation treatment is to purge with nitrogen for 40 minutes, and the reaction is carried out under a nitrogen protective atmosphere; the polymerization temperature is 75℃, and the reaction time is 6 hours; the solid content of the acrylate-based copolymer resin solution is 40%.

[0075] S3. Preparation of self-adaptive crosslinking pressure-sensitive adhesive: Add dynamic crosslinking agent and wetting and leveling agent to acrylate-based copolymer resin solution and stir to mix; add pH adjuster to adjust the pH value of the system to the predetermined range, continue stirring, let stand to degas, and obtain pressure-sensitive adhesive.

[0076] The dynamic crosslinking agent and wetting leveling agent were mixed by stirring at room temperature in a closed environment for 40 minutes; the pH adjuster was triethylamine, and the amount of pH adjuster added was 0.2% of the total mass of the adhesive; the pH value of the system was adjusted to 8.5; after the pH adjustment was completed, stirring was continued at room temperature for 20 minutes; and the standing time for degassing was 15 minutes.

[0077] S4. Coating, Curing and Finished Product Preparation: The pressure-sensitive adhesive liquid is coated onto the pretreated surface of the functionalized substrate, and the thickness of the pressure-sensitive adhesive layer is controlled after drying; the solvent is removed by drying, the release film is attached, and the tape is wound up; the tape is cured in a curing environment to obtain the finished electrolytic adhesive tape for electronic components.

[0078] The pressure-sensitive adhesive was coated using a precision coating machine; the drying process was carried out in a segmented oven with the oven temperature set at 100℃ and the total drying time being 10 minutes; the thickness of the pressure-sensitive adhesive layer after drying was controlled at 30μm; and the curing was carried out for 8 hours in an environment with a temperature of 30℃ and a relative humidity of 55%.

[0079] Comparative Example 1: The only difference between this comparative example and Example 1 is that the acrylate-based copolymer resin is a conventional acrylate copolymer, and its polymerizing monomers are only 77 parts of soft monomers and 15 parts of hard monomers. It does not contain acrylate monomers with β-diketone structures or acrylate monomers with oxazoline groups. All other raw materials, proportions, process steps and parameters are completely consistent with Example 1.

[0080] Comparative Example 2: The only difference between this comparative example and Example 1 is that the dynamic crosslinking agent is replaced with isocyanate crosslinking agent toluene diisocyanate trimer, the amount added is still 1.75 parts, and adipic acid dihydrazide is not used. All other raw materials, ratios, process steps and parameters are completely consistent with Example 1.

[0081] Comparative Example 3: The only difference between this comparative example and Example 1 is that: in step S1, the insulating substrate is not functionalized with a β-diketone silane coupling agent, but is directly coated with pressure-sensitive adhesive after corona treatment. All other raw materials, proportions, process steps and parameters are completely consistent with Example 1.

[0082] Comparative Example 4: The only difference between this comparative example and Example 1 is that the pH adjuster triethylamine is not added in step S3, and the pH value of the system is kept acidic. All other raw materials, ratios, process steps and parameters are completely consistent with Example 1.

[0083] Comparative Example 5: The only difference between this comparative example and Example 1 is that it uses commercially available mainstream brand lithium-ion battery electrolytic tape. This tape uses polyethylene terephthalate as the substrate, the substrate thickness is 31 μm, the dry adhesive thickness of the acrylate pressure-sensitive adhesive layer is 17.5 μm, and the pressure-sensitive adhesive layer formula contains tackifying resin and antioxidants and other small molecule additives. All other raw materials, process steps, parameters and performance test conditions are the same as in Example 1.

[0084] Test item 1, 180° peel strength and electrolyte immersion retention rate test, was conducted in accordance with GB / T2792-2014 "Test Method for 180° Peel Strength of Adhesive Tapes". The test plate used was a clean stainless steel plate that met the standard requirements. The test environment was a standard environment with a temperature of 23°C and a relative humidity of 50%. The test objects included all samples from Examples 1, 2, 3, Comparative Examples 1, 2, 3, 4, and 5. First, the initial peel strength test samples were prepared. Each adhesive tape to be tested was cut into standard samples with a width of 25 mm and a length of 200 mm. After removing the release film, the samples were rolled back and forth twice with a 2 kg standard roller at a speed of 300 mm / min. The samples were then attached to the surface of the stainless steel test plate. After attachment, the samples were placed in a standard environment for 20 min. The 180° peel strength test was conducted using a universal testing machine at a peel speed of 300 mm / min. Each group of samples was tested in parallel for 5 times, and the arithmetic mean was taken as the initial peel strength test result. Subsequently, electrolyte immersion test specimens were prepared using the same cutting and bonding method. After bonding, the specimens were placed in a standard environment for 24 hours. Then, the stainless steel test plate with the specimens bonded to it was completely immersed in commercial lithium-ion battery electrolyte. The electrolyte composition was 1 mol / L lithium hexafluorophosphate, and the solvent was a mixture of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a mass ratio of 1:1:1. The immersed specimens were placed in a constant temperature oven at 85°C for static immersion. After immersion for 500 hours and 1000 hours, the specimens were removed, and the surface of the specimens was gently rinsed with anhydrous ethanol to remove residual electrolyte. After the surface liquid was absorbed with filter paper, the specimens were placed in a standard environment for 2 hours. The 180° peel strength after immersion was tested using the same test method as the initial peel strength. Each group of specimens was tested in parallel for 5 times, and the arithmetic mean was taken as the peel strength test result after immersion. Meanwhile, the peel strength retention rate is calculated based on the test results. The peel strength retention rate is the ratio of the peel strength after immersion to the initial peel strength multiplied by 100%, which characterizes the bonding stability and long-term reliability of each sample in the electrolyte environment.

[0085] Test Item 2, Volume Swelling Rate and Appearance Stability Test of Adhesive Layer after Electrolyte Immersion, was conducted in accordance with GB / T1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber". The test environment was a standard environment with a temperature of 23℃ and a relative humidity of 50%. The test objects included all samples from Examples 1, 2, 3, Comparative Examples 1, 2, 3, 4, and 5. First, swelling rate test samples were prepared. After removing the release film from each adhesive tape to be tested, standard samples with an area of ​​100mm × 100mm were cut. The initial mass of the sample was accurately weighed using an electronic analytical balance, and the initial thickness of the sample was accurately measured using a micrometer. Three samples were prepared in parallel for each group. The samples were then completely immersed in the same commercial lithium-ion battery electrolyte as used in the peel strength test. After sealing, they were placed in a constant temperature oven at 85°C for static soaking. After 500 hours and 1000 hours of soaking, the samples were removed, and the residual electrolyte on the sample surface was quickly rinsed with anhydrous ethanol. The free liquid on the surface was quickly blotted dry with filter paper, and the mass of the sample after soaking was immediately weighed. At the same time, the thickness of the sample after soaking was measured, and the average volume swelling rate of each group of samples was calculated. The volume swelling rate was characterized by the rate of volume change from before soaking. During the soaking process, the appearance changes of each sample were observed and recorded simultaneously, including whether there were any abnormalities such as swelling and overflow of the adhesive layer, edge warping, debonding from the substrate, or cracking of the adhesive layer. This was used to characterize the electrolyte swelling resistance and dimensional stability of each sample.

[0086] Test item 3, Initial Tack and Holding Power Balance Performance Test, was conducted in accordance with GB / T4852-2002 "Test Method for Initial Tack of Pressure-Sensitive Adhesive Tapes" and GB / T4851-2014 "Test Method for Holding Power of Pressure-Sensitive Adhesive Tapes". The test environment was a standard environment with a temperature of 23℃ and a relative humidity of 50%. The test objects included all samples from Examples 1, 2, 3, Comparative Examples 1, 2, 3, 4, and 5. First, the initial tack test was conducted using the inclined plane rolling ball method. The inclination angle of the test device was set to 30°. After removing the release film, each adhesive tape was fixed flat on the standard test plate with the adhesive side facing upwards. A series of standard steel balls conforming to the standard were used to roll freely from the top of the inclined plane. The number of the largest steel ball that could completely stay on the adhesive surface of the tape was recorded. Each group of samples was tested in parallel three times, and the best result was taken as the initial tack test result, which characterizes the initial mounting performance and adaptability to automated production lines of the samples. Subsequently, a holding power test was conducted. Each adhesive tape to be tested was cut into standard samples with a width of 25 mm and a length of 100 mm. After removing the release film, one end of the sample was attached to a clean stainless steel test plate that met the standard requirements, with a bonding area of ​​25 mm × 25 mm. The sample was rolled back and forth twice with a 2 kg standard roller at a speed of 300 mm / min. After bonding, the sample was placed in a standard environment for 20 minutes. The test plate was then vertically fixed on the holding power tester, and a 1 kg standard weight was suspended from the free end of the sample. The time it took for the sample to completely detach from the test plate was recorded. If the sample did not detach within 72 hours, it was recorded as greater than 72 hours. Each group of samples was tested in parallel three times, and the arithmetic mean was taken as the holding power test result. This was used to characterize the cohesive strength and long-term holding power of the sample at room temperature.

[0087] Table 1: Test data on 180° peel strength and retention rate after electrolyte immersion

[0088] Table 2: Test Data of Pressure Sensitive Performance and Electrolyte Swelling Resistance

[0089] I. Detailed description of the appearance stability of each sample after immersion in electrolyte solution Example 1: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer was smooth, without swelling, overflow, warping, delamination, or cracking, and exhibited excellent appearance stability.

[0090] Example 2: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer was smooth, without swelling, overflow, warping, detachment, or cracking, and the appearance was stable.

[0091] Example 3: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer was smooth, without swelling, overflow, warping, delamination, or cracking, and exhibited excellent appearance stability.

[0092] Comparative Example 1: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer swelled severely, softened as a whole, warped over a large area at the edges, and debonded extensively from the substrate, resulting in complete failure of appearance.

[0093] Comparative Example 2: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer swelled significantly, the edges warped, and there was localized adhesive overflow, resulting in poor appearance stability.

[0094] Comparative Example 3: After soaking in electrolyte at 85℃ for 1000h, the adhesive layer itself did not swell significantly, but the edges of the tape warped, and the substrate and adhesive layer interface debonded locally, resulting in interface stability failure.

[0095] Comparative Example 4: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer showed local swelling, accompanied by slight overflow, and the smoothness of the adhesive layer decreased significantly, resulting in insufficient appearance stability.

[0096] Comparative Example 5: After soaking in electrolyte at 85℃ for 1000 hours, the adhesive layer swelled severely and overflowed, with obvious edge warping, localized cracking of the adhesive layer, and poor appearance stability.

[0097] II. Detailed Evaluation of the Balance Effect of Pressure Sensitive Performance of Each Sample Example 1: Excellent initial tack and excellent holding power, perfectly suited for automated high-speed mounting processes and the holding power requirements of long-term fixation of electronic components, achieving an optimal balance between pressure-sensitive performance and cohesive strength.

[0098] Example 2: It has good initial adhesion and excellent holding power, making it suitable for mounting and fixing ultra-thin electronic components. It also has excellent balance in pressure sensitivity performance.

[0099] Example 3: Excellent initial tack and excellent holding power, suitable for application scenarios requiring high temperature resistance and high bonding strength, with excellent balance of pressure-sensitive performance.

[0100] Comparative Example 1: The initial tack is acceptable, but the cohesive strength of the adhesive layer is seriously insufficient, and the holding power is extremely poor, which cannot meet the fixed requirements of electronic components for long-term use, and the pressure-sensitive performance is completely unbalanced.

[0101] Comparative Example 2: The permanent cross-linking system results in extremely poor initial adhesion, making it unsuitable for high-speed automated mounting processes in the production of electronic components, and the pressure-sensitive performance balance is poor.

[0102] Comparative Example 3: The initial tack and holding properties are normal at room temperature, but the interface stability is extremely poor in the electrolyte environment, which cannot meet the long-term reliability requirements of actual use scenarios.

[0103] Comparative Example 4: Excessive initial cross-linking leads to insufficient initial tack, and uneven cross-linking leads to a significant decrease in holding power. This makes it unsuitable for automated mounting and cannot guarantee long-term holding power, resulting in poor pressure-sensitive performance balance.

[0104] Comparative Example 5: The initial adhesion is acceptable, but the holding power is insufficient. Electronic components are prone to displacement and delamination during long-term use, and the pressure-sensitive performance balance is insufficient.

[0105] As can be seen from Examples 1-3 and Comparative Example 1, and Tables 1 and 2, the acrylate monomers containing β-diketone structures and acrylate monomers containing oxazoline groups introduced into the acrylate matrix are the core basis for achieving the environmentally adaptive performance of adhesive tape. Without these two types of functional monomers, the adhesive tape cannot achieve in-situ reinforcement of the cross-linked structure in the electrolyte environment. This will not only lead to a significant decrease in the adhesion retention and swelling resistance after immersion in the electrolyte, but also make it difficult to guarantee the basic cohesive strength and long-term adhesion of the adhesive layer.

[0106] Based on Examples 1-3 and Comparative Example 2, and in conjunction with Tables 1 and 2, it can be seen that the dynamic crosslinking agent of hydrazide type, which matches the monomer containing β-diketone structure, is the key to resolving the inherent contradiction between pressure-sensitive adhesive properties and long-term weather resistance stability of adhesive tape. After replacing it with conventional permanent crosslinking agent, it is impossible to meet the initial adhesive properties required for automated production, and it is also difficult to maintain a stable adhesive effect during long-term immersion in electrolyte. The overall service performance of the adhesive tape will decline significantly.

[0107] As can be seen from Examples 1-3 and Comparative Example 3, and Tables 1 and 2, the directional functionalization pretreatment of the insulating substrate with β-diketone structure is the core of constructing an integrated cross-linked network between the substrate and the adhesive layer. Without this interface modification step, even if the adhesive layer itself has good electrolyte resistance, the interface bonding will fail during long-term electrolyte immersion, and the long-term protection and fixation effect of the adhesive tape cannot be guaranteed.

[0108] As can be seen from Examples 1-3 and Comparative Example 4, and Tables 1 and 2, precise pH control of the adhesive system using a pH adjuster is a crucial step in locking the initial crosslinking degree of the adhesive layer, ensuring pressure-sensitive performance, and enhancing the effect under subsequent working conditions. Without this control step, uneven or excessive crosslinking of the adhesive will occur during preparation and curing, affecting both the fit at room temperature and the performance stability of the adhesive layer in the electrolyte environment.

[0109] As can be seen from Examples 1-3 and Comparative Example 5, and Tables 1 and 2, the adhesive tape system designed in this scheme has achieved a comprehensive improvement in core service performance compared with conventional electrolytic adhesive tape products on the market. At the same time, through the fully integrated formula design, it avoids the industry pain point of small molecule additive precipitation from the root, and is more suitable for the use needs of high reliability and long life electronic components.

[0110] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An electrolytic adhesive tape for electronic components, characterized in that: Includes an insulating substrate and a pressure-sensitive adhesive layer coated on the surface of the insulating substrate; The pressure-sensitive adhesive layer comprises, by weight, the following components: 100 parts of acrylate-based copolymer resin; 0.5-3 parts of dynamic crosslinking agent, wherein the dynamic crosslinking agent is an organic compound containing two or more hydrazide groups; and 0.1-0.5 parts of wetting and leveling agent. The acrylate-based copolymer resin is a linear random copolymer, and its polymeric monomers include 70-85 parts of soft monomers, 10-20 parts of hard monomers, 3-10 parts of acrylate monomers containing β-diketone structures, and 0.5-3 parts of acrylate monomers containing oxazoline groups.

2. The electrolytic adhesive tape for electronic components according to claim 1, characterized in that: The insulating substrate is selected from any one of polyethylene terephthalate film, polyimide film or polypropylene film, and the thickness of the insulating substrate is 12 μm to 50 μm; the surface of the insulating substrate to be coated is pretreated with a silane coupling agent containing a β-diketone structure, and the surface of the insulating substrate has β-diketone functional groups connected by chemical bonds.

3. The electrolytic adhesive tape for electronic components according to claim 1, characterized in that: The dry adhesive thickness of the pressure-sensitive adhesive layer is 5 μm to 30 μm; the dynamic crosslinking agent is selected from one or a combination of two of diacid diacid hydrazide or sebacate diacid hydrazide; the wetting and leveling agent is a polyether modified acrylate leveling agent or a polyester modified acrylate leveling agent, and its mass fraction in the pressure-sensitive adhesive layer does not exceed 0.5%.

4. The electrolytic adhesive tape for electronic components according to claim 1, characterized in that: The soft monomer is selected from one or a combination of two of isooctyl acrylate and butyl acrylate; the hard monomer is selected from one or a combination of two of methyl methacrylate and methyl acrylate; the acrylate monomer containing a β-diketone structure is ethyl acetoacetate methacrylate; the acrylate monomer containing an oxazoline group is 2-isopropenyl-2-oxazoline; the pressure-sensitive adhesive layer does not contain independently added tackifying resin, antioxidant, metal passivating agent or media-resistant additive.

5. A method for preparing an electrolytic adhesive tape for electronic components, characterized in that, An electrolytic adhesive tape for electronic components according to any one of claims 1-4, comprising the following steps: S1. Pretreatment for directional functionalization of insulating substrate: The surface of the insulating substrate to be coated is subjected to corona treatment or plasma treatment, and then a pretreatment working solution prepared with a silane coupling agent containing a β-diketone structure is applied to the treated surface. After drying, a functionalized substrate with β-diketone functional groups on the surface is obtained. S2. Synthesis of acrylate-based copolymer resin: Soft monomers, hard monomers, acrylate monomers containing β-diketone structures, and acrylate monomers containing oxazoline groups are added to a mixed solvent and stirred until homogeneous to obtain a monomer mixture; an initiator is added to the monomer mixture, and after deoxygenation treatment, the mixture is heated to the polymerization temperature to carry out a free radical copolymerization reaction. After the reaction is completed, the mixture is cooled and discharged to obtain an acrylate-based copolymer resin solution. S3. Preparation of adaptive crosslinking pressure-sensitive adhesive: Add dynamic crosslinking agent and wetting and leveling agent to the acrylate-based copolymer resin solution and stir to mix; add pH adjuster to adjust the pH value of the system to a predetermined range, continue stirring, let stand to degas, and obtain pressure-sensitive adhesive; S4. Coating, curing and finished product preparation: The pressure-sensitive adhesive liquid is coated on the pretreated surface of the functionalized substrate, and the thickness of the pressure-sensitive adhesive layer is controlled after drying; the solvent is removed by drying treatment, the release film is attached, and the tape is wound up; the tape is cured in a curing environment to obtain the finished electrolytic adhesive tape for electronic components.

6. The method for preparing an electrolytic adhesive tape for electronic components according to claim 5, characterized in that: In step S1, the pretreatment working solution comprises, by mass, 0.5-2 parts of a silane coupling agent containing a β-diketone structure, 80-90 parts of anhydrous ethanol, and 10-19.5 parts of deionized water; the thickness of the wet film coated with the pretreatment working solution is 5 μm to 10 μm; the drying temperature is 80°C to 100°C, and the drying time is 3 to 5 minutes.

7. The method for preparing an electrolytic adhesive tape for electronic components according to claim 5, characterized in that: In step S2, the mixed solvent is a mixture of ethyl acetate and anhydrous ethanol, with a mass ratio of ethyl acetate to anhydrous ethanol of 2.5:1 to 3.5:1; the initiator is azobisisobutyronitrile, and the amount of initiator added is 0.1% to 0.3% of the total mass of the monomers; the deoxygenation treatment is nitrogen purging for 20 to 40 minutes; the polymerization temperature is 65°C to 75°C, and the reaction time is 4 to 6 hours; the solid content of the acrylate-based copolymer resin solution is 30% to 40%.

8. The method for preparing an electrolytic adhesive tape for electronic components according to claim 5, characterized in that: In step S3, the dynamic crosslinking agent and the wetting and leveling agent are mixed by stirring at room temperature in a closed environment for 20 to 40 minutes; the pH adjuster is triethylamine or N,N-dimethylethanolamine, and the amount of pH adjuster added is 0.05% to 0.2% of the total mass of the adhesive solution; the pH value of the system is adjusted to 7.5 to 8.5; the stirring time is 10 to 20 minutes; and the standing and degassing time is 5 to 15 minutes.

9. The method for preparing an electrolytic adhesive tape for electronic components according to claim 5, characterized in that: In step S4, the drying process is carried out in a segmented oven with the oven temperature set to 80°C to 100°C and the total drying time is 5 to 10 minutes. The thickness of the pressure-sensitive adhesive layer after drying is controlled to be 5 μm to 30 μm. The curing process is carried out in an environment with a temperature of 20°C to 30°C and a relative humidity of 45% to 55% for 4 to 8 hours.

10. The method for preparing an electrolytic adhesive tape for electronic components according to claim 5, characterized in that: In step S1, the corona treatment or plasma treatment ensures that the dyne value of the surface of the insulating substrate to be coated is not less than 42 mN / m.

Images