Electrolytic adhesive tape and its processing technology

Abstract

The application relates to the technical field of adhesives, and particularly discloses an electrolytic adhesive tape and a processing technology thereof. The electrolytic adhesive tape is a multilayer composite structure, and is sequentially stacked from top to bottom with a first release layer, an electroactive adhesive layer, a conductive substrate layer, a pressure-sensitive adhesive layer and a second release layer; wherein the electroactive adhesive layer is made of a composition containing an adhesive main body, a polyionic liquid, mesoporous silica loaded with an ionic liquid and a polar protic inert solvent. The polyionic liquid and the mesoporous silica loaded with the ionic liquid of a specific specification are used to replace traditional solid-state conductive salt, so that high initial adhesion and excellent long-term adhesion stability before the tape is electrified are ensured, fast and complete adhesion loss under a safe low voltage is realized, there is no residual glue on the surface of a stuck object after peeling, the comprehensive performance is excellent, the electrolytic adhesive tape is suitable for electronic component assembly, repair and recycling requirements, and is suitable for industrialized production and application.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to an electric field responsive electrolytic adhesive tape, and also to the processing technology of the electrolytic adhesive tape. Background Technology

[0002] The rapid development of the electronics manufacturing industry has placed higher technical demands on the assembly, repair, and recycling of electronic components. While traditional adhesive tapes can meet the basic needs of fixing components, they are difficult to use for non-destructive separation of the adhered objects when disassembly is required. Not only are adhesive residues left on the surfaces of the adhered objects, but they may also damage the components themselves, affecting subsequent repair or recycling.

[0003] To address the aforementioned issues, electrolytic adhesive tapes that achieve viscosity decay by applying an external electric field have emerged. In existing technologies, these electrolytic adhesive tapes often impart electric field responsiveness by adding liquid ionic liquids or solid conductive salts to the adhesive system. However, this approach has significant technical drawbacks in practical applications: First, liquid ionic liquids are liquid at room temperature, and their addition significantly reduces the cohesive strength of the adhesive, resulting in insufficient initial adhesion. Solid conductive salts, on the other hand, suffer from limited ion conductivity, slow electrical response, and are prone to ion loss over long-term use, affecting the stability of de-adhesion. Second, after electrolysis, liquid ionic liquids tend to migrate, forming oily precipitates on the surface of the adhered objects, while some solid conductive salts leave residues after reaction, both affecting the cleanliness of the adhered objects and subsequent use. Furthermore, the functional component combinations of existing electrolytic adhesive tapes are not sufficiently balanced, making it difficult to simultaneously achieve high initial adhesion, rapid electrical response de-adhesion, and long-term stability, thus limiting their industrial-scale application. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electrolytic adhesive tape and its processing technology. This invention solves the technical problems of existing electrolytic adhesive tapes, such as difficulty in balancing initial adhesion and long-term stability, slow de-adhesion speed in electrical response, and easy residue after peeling. By introducing polyionic liquid and mesoporous silica with specific specifications loaded with ionic liquid to synergistically replace solid conductive salt, the invention achieves the technical effects of high adhesion before energization, rapid and complete de-adhesion under low voltage, stable performance in long-term use, and no residue after peeling.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: An electrolytic adhesive tape comprises, from top to bottom, a first release layer, an electroactive adhesive layer, a conductive substrate layer, a pressure-sensitive adhesive layer, and a second release layer; the electroactive adhesive layer is formed by curing a composition comprising an adhesive matrix, a polyionic liquid, mesoporous silica loaded with the ionic liquid, and a polar proton inert solvent.

[0006] The core innovation of this invention lies in replacing traditional solid conductive salts with a synergistic system of "polyionic liquid + mesoporous silica loaded with ionic liquid". Combined with a polar proton inert solvent, it achieves precise control of adhesive performance. The particle size and pore size of the mesoporous silica are key technical parameters, which are adapted to the loading, storage and release requirements of ionic liquids. The synergistic mechanism of each component is as follows: 1. The polyionic liquid is an imidazolium-based polyionic liquid, which combines the high ionic conductivity of ionic liquids with the excellent mechanical properties of polymers. It is solid at room temperature, has good compatibility with the adhesive matrix, and does not reduce the cohesive strength of the adhesive layer. It ensures the high initial adhesion of the electroactive adhesive layer and provides a stable ion conduction channel for electrochemical reactions, thereby improving the electro-response sensitivity.

[0007] 2. The mesoporous silica loaded with ionic liquid is of customized specifications, with a particle size of 200nm to 10μm and a mesopore size of 10nm to 50nm. This pore size range enables efficient adsorption and stable storage of ionic liquid, and ensures the slow and continuous release of ionic liquid under the action of an electric field. The particle size range ensures that the mesoporous silica is uniformly dispersed in the adhesive matrix, avoiding the agglomeration of small-diameter particles and preventing large-diameter particles from affecting the coating performance and interfacial adhesion. As an "ionic liquid reservoir," this mesoporous silica can continuously compensate for the ion loss generated in the electrochemical reaction during the long-term use of the tape, significantly improving the long-term adhesion and de-adhesion stability of the electroactive adhesive layer. At the same time, the mesoporous silica is an inorganic filler, which can physically reinforce the adhesive layer and further improve the mechanical properties of the adhesive layer.

[0008] 3. The polar protic inert solvent (dimethyl carbonate + propylene carbonate) can effectively promote the dissociation of polyionic liquid and the release of ionic liquid loaded in mesoporous silica, accelerate the migration efficiency of ions under an electric field, and quickly initiate an electrochemical reaction under low voltage, thereby destroying the interfacial bonding force between the adhesive layer and the adhered object and achieving rapid debonding. Moreover, this solvent system has good compatibility with functional components and will not cause swelling or performance degradation of the adhesive layer.

[0009] Preferably, the polyionic liquid is an imidazolium-based polyionic liquid, specifically selected from at least one of poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide), poly(1-butyl-3-vinylimidazolium tetrafluoroborate), and poly(1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide). The ionic groups of this type of polyionic liquid are similar in structure to the supported ionic liquid, which can form a continuous ion conduction pathway and further improve the electro-response efficiency.

[0010] Preferably, in the mesoporous silica loaded with ionic liquid, the ionic liquid loading is 10-50% of the mass of the mesoporous silica. If the loading is too low, the ion reservoir effect is not obvious and cannot effectively compensate for ion loss; if it is too high, it will affect the compatibility between the mesoporous silica and the adhesive matrix, resulting in a decrease in the cohesive strength of the adhesive layer. The loaded ionic liquid is an ionic liquid containing imidazolium cations and fluorinated anions, selected from at least one of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. This type of ionic liquid has good compatibility with polyionic liquids and high ion conduction efficiency, which is suitable for the requirements of electrical stimulation detack.

[0011] Preferably, the polar protic inert solvent is a mixture of dimethyl carbonate and propylene carbonate in a mass ratio of (3-10):10. This solvent system can ensure the storage and use stability of the electroactive adhesive layer and provide excellent low-temperature ionic conductivity, making it suitable for the conventional use environment of electronic components.

[0012] Preferably, the conductive substrate layer is a conductive nonwoven fabric, metal foil, or a polymer film with a metallized surface. Such substrates have good conductivity and formability, which can ensure that the electric field acts uniformly on the electroactive adhesive layer and avoid the problem of incomplete local deadhesion. At least one of 1 to 10 parts by weight of tin oxide and 1 to 5 parts by weight of anionic alkali metal phosphate can be added to the electroactive adhesive layer composition. Tin oxide can act as a conductive reinforcing filler to reduce the adhesive layer resistance, and anionic alkali metal phosphate can release protons to improve ionic conductivity and further shorten the deadhesion response time.

[0013] This invention also provides a processing method for the above-mentioned electrolytic adhesive tape, comprising the following steps: S1. Preparation of electroactive adhesive layer mixture: By weight, 100 parts of adhesive matrix, 5-20 parts of polyionic liquid, 1-10 parts of mesoporous silica loaded with ionic liquid and 5-50 parts of polar proton inert solvent are mixed evenly to obtain the mixture. S2. Coating and curing: The mixture obtained in step S1 is uniformly coated on the release surface of the first release layer and cured to form an electroactive adhesive layer. S3, Composite conductive substrate: The first release layer with an electroactive adhesive layer is composited with one side of the conductive substrate layer, so that the electroactive adhesive layer is transferred and adhered to the surface of the conductive substrate layer. S4. Preparation of pressure-sensitive adhesive layer: Apply pressure-sensitive adhesive to the release surface of the second release layer, and form a pressure-sensitive adhesive layer by drying or curing. S5, Composite pressure-sensitive adhesive layer: The second release layer with pressure-sensitive adhesive layer is composited with the other side of the conductive substrate layer, so that the pressure-sensitive adhesive layer adheres to the surface of the conductive substrate layer; S6. Curing: The semi-finished product obtained in step S5 is rolled up and cured to obtain the electrolytic adhesive tape.

[0014] This process employs a step-by-step coating and layered lamination method to prepare multilayer electrolytic adhesive tapes, effectively avoiding mutual interference between different adhesive layer components and ensuring the stability of each layer's performance and interlayer bonding strength. The entire process is simple, highly controllable, and requires no complex specialized equipment, making it suitable for large-scale industrial production. Specifically, the mesoporous silica loaded with ionic liquids needs to be prepared in advance to ensure effective loading and stable adsorption of the ionic liquids. The adhesive matrix can be selected from UV-curable acrylate prepolymers or thermosetting epoxy resin prepolymers, with corresponding curing methods of UV curing or thermosetting, adapting to different production scenarios and process requirements.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent initial adhesion and good long-term stability: The polyionic liquid is a solid polymer with good compatibility with the adhesive matrix, which will not reduce the cohesive strength of the adhesive layer and ensures high initial adhesion before the tape is energized; the customized mesoporous silica serves as an ion reservoir, with pore size and particle size adapted to the storage and release of the ionic liquid, which can continuously compensate for ion loss. After accelerated aging test, the tape can maintain an adhesion strength of more than 95% after 30 days, which solves the problem of long-term performance degradation of traditional electrolytic adhesive tapes.

[0016] 2. Low-voltage, rapid, and efficient de-adhesion: The polyionic liquid and the loaded ionic liquid form a synergistic ion conduction system. Combined with a specific ratio of polar proton inert solvent, the efficiency of ion dissociation and migration is significantly improved. Under a safe low voltage of 9V to 48V, the tape can be rapidly and completely de-adhesive within 60 seconds, with a de-adhesion efficiency of over 98%, meeting the needs of rapid disassembly of electronic components.

[0017] 3. No residue after peeling, good cleanliness: Polyionic liquid is a polymeric ionic component that does not undergo liquid migration. The ionic liquid loaded in the mesoporous silica is consumed or fixed in the mesoporous channels after electrochemical reaction. No free components migrate to the surface of the adhered object, achieving clean peeling. There are no glue-like or oily residues on the surface of the adhered object, which can be directly used for subsequent rework or recycling processes.

[0018] 4. Excellent mechanical properties and good coatability of the adhesive layer: The particle size and pore size of the mesoporous silica are customized, which can be uniformly dispersed in the adhesive matrix. It not only plays a physical reinforcing role, but also improves the tensile strength, shear strength and other mechanical properties of the electroactive adhesive layer in combination with the polymer characteristics of polyionic liquid, avoiding problems such as interlayer delamination and adhesive layer damage during the use of the tape; at the same time, it does not affect the coating performance of the adhesive layer, ensuring that the adhesive layer surface is uniform and defect-free.

[0019] 5. Reasonable structure and stable process: The tape adopts a five-layer composite structure design, with each layer having a clear function and working together to ensure good overall structural stability; the processing technology adopts a step-by-step coating and layer-by-layer lamination method, which effectively avoids component interference, resulting in high product performance consistency. Moreover, the process is simple and easy to operate, making it suitable for large-scale industrial production.

[0020] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. All raw materials not specifically described are commercially available conventional raw materials, and all processes not specifically described are conventional processes.

[0021] Raw material preparation Mesoporous silica loaded with ionic liquid (IL@MSiO2): 5g of mesoporous silica (particle size 500nm, mesopore size 20nm) was added to 100mL of ethanol solution containing 1.5g of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), and ultrasonically treated for 45 minutes to allow the ionic liquid to be fully adsorbed onto the pores and surface of the mesoporous silica. After centrifugation, the product was vacuum dried at 60℃ for 12 hours to obtain the final product. Thermogravimetric analysis showed that the ionic liquid loading was approximately 25% of the mass of the mesoporous silica. Example

[0022] This embodiment provides an electrolytic adhesive tape, which consists of the following layers from top to bottom: a first release layer 1 (PET release film, 50 μm thick), an electroactive adhesive layer 2 (35 μm thick), a conductive substrate layer 3 (conductive PP nonwoven fabric, 15 μm thick), a pressure-sensitive adhesive layer 4 (acrylate pressure-sensitive adhesive, 20 μm thick), and a second release layer 5 (glassine release paper, 70 μm thick).

[0023] The specific processing technology for this electrolytic adhesive tape is as follows: S1. Preparation of electroactive adhesive layer mixture: By weight, take 100 parts of UV-curable acrylate prepolymer as the adhesive body, add 10 parts of poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide) (PIL-1), 5 parts of the above-prepared IL@MSiO2, and then add a polar protic inert solvent mixture composed of 3 parts of dimethyl carbonate and 10 parts of propylene carbonate. Add the above materials to a kneader and stir at 60°C until uniformly mixed to obtain the electroactive adhesive layer mixture. S2. Coating and curing: The mixture obtained in step S1 is uniformly coated onto the release surface of the first release layer 1 using a coating machine, and the wet film thickness is controlled to be 35μm. Then, it is cured by ultraviolet light irradiation to form an electroactive adhesive layer 2. S3, Composite conductive substrate: The first release layer 1 with electroactive adhesive layer 2 is bonded to one side of conductive PP nonwoven fabric (conductive substrate layer 3) by means of a pressure roller. The pressure roller pressure is 0.3MPa, so that the electroactive adhesive layer 2 is tightly transferred and adhered to the surface of the conductive substrate layer 3. S4. Preparation of pressure-sensitive adhesive layer: The acrylic pressure-sensitive adhesive is uniformly coated on the release surface of the second release layer 5, and the wet film thickness is controlled to be 20μm. After drying with hot air at 80℃ for 3 minutes, pressure-sensitive adhesive layer 4 is formed. S5, Composite pressure-sensitive adhesive layer: The second release layer 5 with pressure-sensitive adhesive layer 4 is bonded to the other side of the conductive substrate layer 3 by means of a pressure roller. The pressure roller pressure is 0.3MPa, so that the pressure-sensitive adhesive layer 4 is tightly adhered to the surface of the conductive substrate layer 3, and a semi-finished product is obtained. S6. Curing: The semi-finished product obtained in step S5 is rolled up and placed in an environment of 40°C for curing for 48 hours to obtain the finished electrolytic adhesive tape. Example

[0024] The difference between this embodiment and Example 1 is that the mesoporous silica used has a particle size of 2 μm and a mesopore size of 30 nm; in step S1, the polyionic liquid is replaced with 10 parts of poly(1-butyl-3-vinylimidazolium tetrafluoroborate) (PIL-2), and the ionic liquid supported in IL@MSiO2 is replaced with 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6). The remaining raw materials and process parameters are the same as in Example 1. Example

[0025] The difference between this embodiment and Example 1 is that the mesoporous silica used has a particle size of 8 μm and a mesopore size of 40 nm; in step S1, the amount of polyionic liquid added is 15 parts, the amount of IL@MSiO2 added is 8 parts, and the polar protic inert solvent is 5 parts of dimethyl carbonate + 10 parts of propylene carbonate. The remaining raw materials and process parameters are the same as in Example 1.

[0026] Performance testing The electrolytic adhesive tapes prepared in Examples 1-3 were subjected to performance tests. The test methods and results are as follows: 1. Adhesive strength test before power-on: The tape was cut into 25mm wide samples and attached to the test surface of a stainless steel plate. It was then rolled back and forth three times with a 2kg standard roller. After being left at room temperature for 24 hours, a 180° peel test was performed using a universal tensile testing machine at a speed of 300mm / min. The results showed that the adhesive strengths of Examples 1-3 were 16.5 N / 25mm, 15.8 N / 25mm, and 17.2 N / 25mm, respectively, all exhibiting excellent initial adhesive strength.

[0027] 2. De-adhesion test after power-on: The stainless steel plate with the adhesive tape bonded to it was used as the cathode, and the conductive substrate layer 3 of the tape was used as the anode. A 30V DC voltage was applied for 60 seconds, and then the power was cut off. A 180° peel test was then performed again. The results showed that the residual adhesion of Examples 1-3 was 0.3 N / 25mm, 0.4 N / 25mm, and 0.2 N / 25mm, respectively, with a de-adhesion efficiency of over 98%, and the tape was completely de-adhesive. After peeling, microscopic observation showed no obvious residue on the surface of the stainless steel plate, achieving clean peeling.

[0028] 3. Long-term stability test: The tape was stored in a sealed container at 25°C for 30 days. The adhesion before energization was tested using the method described above, and the adhesion strength retention rate was calculated. The results showed that the adhesion strength retention rates of Examples 1-3 were 98.2%, 97.5%, and 98.6%, respectively, all above 95%, demonstrating excellent long-term stability.

[0029] 4. High and low temperature adaptability test: After the tape was refrigerated at -20℃ for 24 hours and baked at 85℃ for 24 hours, the de-adhesion effect under 30V voltage was tested. The results showed that the tape could completely de-adhese within 60 seconds, with residual adhesion ≤0.5 N / 25mm. There was no cracking, delamination or particle agglomeration of the adhesive layer, indicating good high and low temperature adaptability.

[0030] 5. Coating performance test: Observe the surface condition of the electroactive adhesive layer after coating. The adhesive layers of Examples 1-3 all have smooth surfaces, no pinholes, and no particle protrusions, and have excellent coating performance, which meets the needs of continuous industrial production.

[0031] The above description is only a preferred embodiment of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrolytic adhesive tape, characterized in that, The first release layer (1), the electroactive adhesive layer (2), the conductive substrate layer (3), the pressure-sensitive adhesive layer (4), and the second release layer (5) are stacked sequentially from top to bottom; the electroactive adhesive layer (2) is formed by curing a composition comprising an adhesive matrix, a polyionic liquid, mesoporous silica loaded with ionic liquid, and a polar proton inert solvent.

2. The electrolytic adhesive tape according to claim 1, characterized in that, The polyionic liquid is an imidazolium-based polyionic liquid, selected from at least one of poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide), poly(1-butyl-3-vinylimidazolium tetrafluoroborate), and poly(1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide).

3. The electrolytic adhesive tape according to claim 1, characterized in that, In the mesoporous silica loaded with the ionic liquid, the ionic liquid loading is 10-50% of the mass of the mesoporous silica; the particle size of the mesoporous silica is 200 nm-10 μm, and the mesopore size is 10 nm-50 nm; the ionic liquid is an ionic liquid containing imidazolium cations and fluorinated anions, selected from at least one of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

4. The electrolytic adhesive tape according to claim 1, characterized in that, The polar protic inert solvent is a mixture of dimethyl carbonate and propylene carbonate in a mass ratio of (3-10):

10.

5. The electrolytic adhesive tape according to claim 1, characterized in that, The conductive substrate layer (3) is a conductive nonwoven fabric, metal foil, or a polymer film with a metal coating on its surface; the composition for preparing the electroactive adhesive layer (2) may also include at least one of 1 to 10 parts by weight of tin oxide and 1 to 5 parts by weight of anionic alkali metal phosphate.

6. A processing method for preparing the electrolytic adhesive tape as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Preparation of electroactive adhesive layer mixture: By weight, 100 parts of adhesive matrix, 5-20 parts of polyionic liquid, 1-10 parts of mesoporous silica loaded with ionic liquid and 5-50 parts of polar proton inert solvent are mixed evenly to obtain the mixture. S2. Coating and curing: The mixture obtained in step S1 is uniformly coated on the release surface of the first release layer (1) and cured to form an electroactive adhesive layer (2). S3, Composite conductive substrate: The first release layer (1) with the electroactive adhesive layer (2) is composited with one side of the conductive substrate layer (3), so that the electroactive adhesive layer (2) is transferred and adhered to the surface of the conductive substrate layer (3); S4. Preparation of pressure-sensitive adhesive layer: Apply pressure-sensitive adhesive to the release surface of the second release layer (5), and form a pressure-sensitive adhesive layer (4) after drying or curing. S5, Composite pressure-sensitive adhesive layer: The second release layer (5) with pressure-sensitive adhesive layer (4) is composited with the other side of the conductive substrate layer (3) so that the pressure-sensitive adhesive layer (4) adheres to the surface of the conductive substrate layer (3); S6. Curing: The semi-finished product obtained in step S5 is rolled up and cured to obtain the electrolytic adhesive tape.

7. The processing technology according to claim 6, characterized in that, In step S1, at least one of 1 to 10 parts by weight of tin oxide and 1 to 5 parts by weight of anionic alkali metal phosphate may be added to the mixture.

8. The processing technology according to claim 6, characterized in that, In step S2, the curing process is either thermosetting or UV curing; in steps S3 and S5, the composite process is completed by roller bonding.

9. The processing technology according to claim 6, characterized in that, The method for preparing the mesoporous silica loaded with ionic liquid is as follows: mesoporous silica particles are dispersed in an ethanol solution of ionic liquid, ultrasonically treated for 30-60 minutes, centrifuged, and then vacuum dried at 60°C for 12 hours to obtain the finished product.

10. The processing technology according to claim 6, characterized in that, The adhesive is primarily a UV-curable acrylate prepolymer or a thermosetting epoxy resin prepolymer; the pressure-sensitive adhesive is an acrylate-based pressure-sensitive adhesive.