UV (ultraviolet) activated composition capable of being subjected to electrified visbreaking as well as preparation method and application of UV activated composition

Abstract

The invention discloses a UV (ultraviolet) activated composition capable of being subjected to electrified visbreaking as well as a preparation method and application thereof. The UV activation composition comprises epoxy modified acrylic resin, epoxy resin, a photoinitiator, a photosensitizer, a conductive filler and the like. The UV-activated composition can be used for preparing adhesive films, adhesive tapes and the like. The UV-activated composition provided by the invention combines two advantages of high strength of UV curing and controllable viscosity reduction of electric triggering, not only can realize high-strength permanent bonding, but also can realize no-damage and controllable disassembly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of adhesive tape, and particularly relates to a UV-activated composition capable of reducing adhesion by electricity and a preparation method and application thereof. BACKGROUND

[0002] In the assembly process of high-end manufacturing industries such as consumer electronics (smartphones, tablets), semiconductor packaging, automotive electronics and precision optical elements, it is often necessary to provide a high-strength permanent bonding, but at the same time, it is also necessary to achieve non-damageable and controllable disassembly. This demand is particularly prominent in scenarios such as repair, rework, upgrade or temporary fixing during production.

[0003] Although traditional UV-cured adhesives have the advantages of fast curing speed, rapid positioning and high-strength bonding through ultraviolet irradiation, once fully cured, the bonding is permanent. When disassembled, a large mechanical force needs to be applied, which can easily cause damage or breakage of expensive components (such as glass covers, ceramic substrates, chips) or precision structural parts. Chemical debonding agents may corrode parts and are not suitable for narrow spaces. Therefore, there is an urgent need in the market for an adhesive material that combines the advantages of UV-cured high-strength and electrically triggered controllable debonding. It can provide high bonding strength when needed, and at other times, it can achieve "one-key" and clean separation through a simple, fast and local stimulus.

[0004] The main technical problems in the prior art are as follows: (1) Traditional UV-cured epoxy or acrylate adhesives form a highly cross-linked three-dimensional network after complete curing, which has extremely high bonding strength and cohesion, and becomes permanent bonding. When disassembled, only mechanical force can be used to pry it open, which can easily cause damage, deformation or residue of the precision components (such as glass, ceramic, chip, composite material) or their own structure.

[0005] (2) Existing thermal debonding tapes or hot melt adhesives need to place the entire component or a larger area in a high-temperature environment (usually >100°C) to achieve debonding. This global heating method can cause irreversible thermal damage to surrounding heat-sensitive components (such as lithium batteries, liquid crystal displays, plastic parts, optical lenses), and has high energy consumption and long cycle time.

[0006] (3) Existing chemical debonding agents require soaking time and may cause corrosion and pollution; the force and result of mechanical disassembly are difficult to predict and control.

[0007] (4) There are technical challenges in combining electrical conductivity and UV curability in an epoxy resin system. Simple mixing may result in UV light being shielded by conductive fillers, preventing deep curing, or the conductive network may damage the mechanical properties.

[0008] For example, existing patent CN 115895519 A describes an electrolytic adhesive and double-sided tape, providing a method for preparing an electro-tack-reducing pressure-sensitive adhesive. It achieves excellent electro-tack reduction by adding solid conductive salts and polar proton inert solvents, but its bonding strength before energization is low. Existing patent CN 119193019 A describes an electro-tack-reducing tape, its preparation method, and its application, providing a UV-curable pressure-sensitive adhesive. By doping with porous carbon, UV light can penetrate the adhesive layer, causing cross-linking and curing. Simultaneously, after energization, the conductive particles aggregate, causing the adhesive to lose its tackiness, thus achieving a tack-reducing effect. However, while the entire system has strong bonding performance, its high-temperature holding power is poor, lasting only 5-6 hours, far below the heat resistance requirements of applications such as batteries.

[0009] In summary, existing high-strength structural adhesives present a fundamental contradiction in achieving controllable, non-destructive, and rapid disassembly after curing. There is an urgent need to solve technical challenges such as disassembly damage, global thermal impact, process efficiency and controllability, and integrated performance. Summary of the Invention

[0010] The main objective of this invention is to provide an electrically conductive, non-sticky UV-activated composition, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0011] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of the present invention provides an electrically conductive and non-sticky UV-activated composition comprising the following components in parts by weight: 15-35 parts epoxy-modified acrylic resin, 10-20 parts epoxy resin, 0.1-0.5 parts photoinitiator, 0.2-1 parts photosensitizer, and 30-80 parts conductive filler. Furthermore, the UV-activated composition satisfies the following conditions: a) When the UV-activated composition is cured to form a film, the conductive filler is able to form a conductive network in the film, and the conductive network is able to generate heat when energized; b) The thermal decomposition temperature or glass transition temperature of the resin component in the film is lower than or equal to the temperature of the conductive network after a set current is applied and the current is maintained for a set duration.

[0012] A second aspect of the present invention provides a method for preparing the electrically conductive and tack-reducing UV-activated composition, comprising: providing an epoxy-modified acrylic resin; The UV-activated composition is prepared by uniformly mixing the epoxy-modified acrylic resin, epoxy resin, photoinitiator, and conductive filler.

[0013] A third aspect of the invention provides an adhesive film formed from the electrically conductive, anti-adhesion UV-activated composition.

[0014] A fourth aspect of the present invention provides a method for preparing an adhesive film, comprising: coating the electrically conductive and anti-adhesive UV-activated composition onto the surface of a first release film to form a coating, and after drying, covering the surface of the coating with a second release film to obtain the adhesive film.

[0015] A fifth aspect of the present invention provides an adhesive tape comprising a substrate layer, an adhesive layer coated on the surface of the substrate layer, and a release layer disposed on the adhesive layer; said adhesive layer is formed from the electrically conductive, anti-adhesive UV-activated composition.

[0016] A sixth aspect of the present invention provides a method for non-destructive disassembly of an adhesive structure, the adhesive structure comprising a first object and a second object fixedly connected by an adhesive layer, the adhesive layer being formed by curing the electrically conductive, anti-adhesion UV-activated composition, and the method comprising: A set current is applied to the adhesive layer for a set duration, causing the conductive network therein to heat up until the temperature of the adhesive layer is equal to or higher than the thermal decomposition temperature or glass transition temperature of the resin component in the adhesive layer, thereby allowing the first object and the second object to separate without damage.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The technology provided by this invention transforms the bonding process from "unidirectional and permanent" to "bidirectional and controllable". When the adhesive film is bonded: through UV irradiation, a permanent bond with ultra-high strength, high durability, heat resistance and chemical resistance of the same level as traditional high-performance epoxy adhesives is obtained. When the adhesive film is removed: by applying a safe low voltage, the bonding interface is "actively failed" within tens of seconds, enabling the components to be separated almost 100% without damage and with cleanliness. This completely eliminates the problem of component damage during rework, repair and recycling.

[0018] (2) The technology provided by this invention offers a precise and localized triggering method, greatly protecting sensitive components. Compared with heat-reducing adhesive technology that requires overall heating, electric heating is a localized and precise energy application method. When the tape / film of this invention is heated by electricity, the heat-affected zone is extremely small, and Joule heat is generated only in the conductive network inside the film. The heat is strictly confined to the bonding interface, avoiding the transfer of heat to the precision, heat-sensitive components being bonded (such as organic electro-laser display screens, lithium batteries, plastic parts, and chips). Moreover, it has high energy efficiency, consuming electrical energy only in the small area that needs to be disassembled and for a short time, making it more energy-efficient than traditional oven heating.

[0019] (3) The technology provided by this invention significantly improves production and maintenance efficiency and reduces overall costs. Specifically, the adhesive film provided by this invention has an extremely fast disassembly response. From the moment the power is applied to the loss of adhesive force, the entire process is usually completed within 10-60 seconds. Compared with waiting for the oven to heat up or using chemical solvents, the efficiency is increased by several times or even dozens of times. Moreover, it can simplify the operation process. Operators only need to use a simple DC power supply. There is no need for large heating equipment or complex chemical treatments, which greatly simplifies the process. It can also reduce the total cost. Although the material itself may be expensive, the high yield, low component damage rate, high repair success rate and shortened operation time significantly reduce the overall cost of manufacturing, after-sales and recycling.

[0020] (4) The technology provided by this invention has excellent process applicability and performance reliability. The adhesive film is compatible with existing UV curing equipment, and its initial curing stage is fully compatible with existing UV dispensing, irradiation and curing production lines, without the need for major equipment investment. Moreover, the bonding performance is stable. Under normal use conditions without power, its cured mechanical properties and environmental resistance are no different from conventional epoxy adhesives, ensuring high reliability of the product throughout its life cycle. In addition, it has the advantages of being clean and residue-free. After the tack is reduced, the adhesive layer usually loses its cohesive force due to softening, or is confined to one of the substrates. The interface separation is clean, with no adhesive residue or only a small amount of thin layer that is easy to clean, avoiding contamination and subsequent cleaning work.

[0021] (5) The tape / film provided by this invention makes designs that were previously "unrepairable" due to bonding become repairable designs. Moreover, it allows for more advanced modular designs, where each module can be fixed by high-strength bonding and can be easily separated when upgrading or replacing. In production, it can also be used in tooling stages that require temporary high-strength fixing and may need adjustment after final calibration, facilitating temporary positioning and adjustment. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a UV-activated epoxy film that can be electrically de-adhesive in a typical embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a UV-activated epoxy tape that can be electrically depressurized in a typical embodiment of the present invention.

[0024] Reference numerals: 1-Second release film layer, 2-Adhesive layer, 3-First release film layer, 4-Release film layer, 5-Adhesive layer, 6-Substrate layer. Detailed Implementation

[0025] In view of the problems existing in the prior art, the inventors of this invention have conducted extensive and in-depth research and have provided a UV-activated composition that can reduce adhesion through electrical conduction, as well as its preparation method and application. This composition can be cured by UV activation to achieve the bonding strength of structural adhesives and semi-structural adhesives, and can also be de-adhesive by applying low-voltage direct current to make the bonding interface lose its adhesive force quickly.

[0026] The following will provide a further explanation of the technical solution, its implementation process, and its principles.

[0027] The first aspect of the present invention provides an electrically conductive and non-sticky UV-activated composition comprising the following components in parts by weight: 15-35 parts epoxy-modified acrylic resin, 10-20 parts epoxy resin, 0.1-0.5 parts photoinitiator, 0.2-1 parts photosensitizer, and 30-80 parts conductive filler. Furthermore, the UV-activated composition satisfies the following conditions: a) When the UV-activated composition is cured to form a film, the conductive filler is able to form a conductive network in the film, and the conductive network is able to generate heat when energized; b) The thermal decomposition temperature or glass transition temperature (Tg) of the resin component in the film is lower than or equal to the temperature of the conductive network after a set current is applied and the current is maintained for a set duration.

[0028] In some embodiments, the UV-activated composition further includes the following components calculated in parts by weight: 2 to 8 parts curing agent, 2 to 8 parts thickener, and 2 to 8 parts solid conductive salt.

[0029] In some embodiments, the UV-activated composition further includes selectively added or omitted additives, such as toughening agents, leveling agents, or coupling agents. Further, the coupling agents include, but are not limited to, silane coupling agents.

[0030] In some embodiments, the method for preparing the epoxy-modified acrylic resin includes: reacting a first reactive monomer and a second reactive monomer at 60-80°C in the presence of a free initiator to obtain the epoxy-modified acrylic resin, wherein the first reactive monomer contains an acrylic structural unit and the second reactive monomer is selected from ester substances.

[0031] Furthermore, the first reactive monomer includes one or more of the following: methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate (2-HEA), tetrahydrofuran methacrylate, etc., but is not limited to these.

[0032] Furthermore, the first reactive monomer comprises a combination of methyl acrylate, butyl acrylate, and 2-hydroxyethyl acrylate.

[0033] Furthermore, the second reactive monomer includes glycidyl methacrylate (GMA).

[0034] Furthermore, the mass ratio of methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate and glycidyl methacrylate is 60~90:10~20:2~8:10~20.

[0035] Furthermore, the free radical initiator includes, but is not limited to, azobisisobutyronitrile.

[0036] Furthermore, the reaction is carried out in a solvent, including but not limited to ethyl acetate.

[0037] Furthermore, the number average molecular weight of the epoxy-modified acrylic resin is 40,000 to 200,000.

[0038] Specifically, the preparation method of the epoxy-modified acrylic resin includes: mixing one or more of methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, tetrahydrofuran methacrylate, and glycidyl methacrylate with azobisisobutyronitrile and ethyl acetate; then adding one-third of the mixture to a four-necked flask and stirring under nitrogen protection in an oil bath at 65°C; adding the remaining two-thirds of the mixture to the four-necked flask by titration for 4 hours; after all titration is completed, reacting at 65°C for 4 hours, then raising the temperature to 75°C and holding for 1 hour to remove residual monomers; after the reaction is completed, removing the reaction solution, adding a certain amount of ethyl acetate solvent, and adjusting the reaction solution to a solid content of 40% to obtain the epoxy-modified acrylic resin solution.

[0039] In some embodiments, the epoxy resin includes any one or a combination of several of bisphenol A type epoxy resin, phenolic modified epoxy resin, amino epoxy resin, aliphatic epoxy resin, etc., but is not limited thereto. In this invention, the epoxy resin is one that can be effectively cured by a cationic mechanism, and whose cured product can be significantly softened or degraded upon heating. For example, a rigid epoxy resin with a high glass transition temperature is selected, so that when heated above its Tg, the modulus decreases sharply, and the viscosity reduction effect is more obvious.

[0040] In some embodiments, the photoinitiator is an iodonium salt, including, but not limited to, any one or a combination of several of the following: diphenyliodonium chloride, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, and tetraphenylborate. In this invention, a cationic photoinitiator that is sensitive to UV light and has high acid-generating efficiency is selected, and its compatibility with the conductive filler system is considered to ensure effective polymerization initiation even in the presence of filler.

[0041] In some embodiments, the photosensitizer includes any one or a combination of several of fluorenes, fluorenones, anthraquinones, anthrones, fluoranthenes, benzyl ketals, etc., but is not limited thereto. In this invention, the photoinitiator decomposes upon exposure to light, and the resulting free radicals or cations initiate the epoxy ring-opening curing reaction. However, because the photoinitiator has a narrow wavelength range, only light sources within a very short wavelength range can decompose it. The role of the photosensitizer is to broaden the wavelength range, making the photoinitiator easier to decompose and thus improving the curing efficiency.

[0042] Furthermore, the photosensitizer includes 2-isopropylthioxanthraquinone.

[0043] In some embodiments, the curing agent is a thiol-based epoxy curing agent, which includes, but is not limited to, at least one of trimethylolpropane trimercaptoacetate, tetra(3-mercaptopropionic acid) ester, pentaerythritol tetra(3-mercaptobutyrate) ester, hexafunctional thiols, etc.

[0044] In some embodiments, the solid conductive salt is an organic sulfonate containing an alkali metal, including, but not limited to, at least one of lithium trifluoromethanesulfonate and potassium perfluorooctyl sulfonate. In this invention, upon energization, the solid conductive salt undergoes ion migration under the influence of an electric field, forming an ion migration flow within the cured adhesive. This disrupts the cross-linked structure within the adhesive, reducing its cohesive strength. Additionally, some ions are released to the bonding interface between the adhesive and the substrate, thereby damaging the bond strength between the adhesive and the substrate.

[0045] In some embodiments, the thickener includes, but is not limited to, any one or a combination of several of fumed silica, cellulose, etc.

[0046] In some embodiments, the conductive filler includes any one or a combination of several of nickel powder, copper powder, silver powder, carbon nanotubes, graphene, and carbon black, but is not limited to these. The conductive filler is the core component for achieving efficient electrothermal conversion. Furthermore, the conductive filler can be surface-chemically modified to improve its dispersibility and compatibility in the organic epoxy resin system, prevent agglomeration, and ensure a uniform and stable conductive network, thereby guaranteeing uniform heating and consistent performance.

[0047] Generally, conductive fillers scatter and absorb ultraviolet light, hindering photoinitiators from absorbing photons, leading to insufficient curing depth or incomplete curing of the underlying layer. Therefore, this invention precisely controls the amount of conductive filler added, ensuring it reaches or slightly exceeds the percolation threshold to minimize the UV shielding effect while maintaining conductivity. Furthermore, by optimizing the intensity and duration of UV irradiation, using a light source with a wavelength offset from the filler's absorption peak, or employing a special multilayer structure design, it is ensured that the interface layer can be effectively cured by UV light.

[0048] Furthermore, this invention employs a uniform mixing and stable film-forming process. The dispersion process utilizes powerful methods such as high-shear emulsification, three-roll milling, or ultrasonic treatment to ensure that the conductive filler is uniformly dispersed in the resin at the nanoscale, forming a stable, sedimentation-free slurry. The film-forming process employs precision coating technology to control the coating speed, gap, and temperature, resulting in a film with uniform thickness, no defects, and no bubbles. The uniformity of thickness ensures the uniformity of heat generation during electrical conduction and the consistency of the final viscosity reduction effect.

[0049] Furthermore, the nickel powder, copper powder, and silver powder are in the form of spheres, flakes, or chains.

[0050] A second aspect of the present invention provides a method for preparing the aforementioned electrically resistant and non-sticky UV-activated composition, comprising: We provide epoxy-modified acrylic resins; The UV-activated composition is prepared by uniformly mixing the epoxy-modified acrylic resin, epoxy resin, photoinitiator, and conductive filler.

[0051] A third aspect of the invention provides an adhesive film formed from the electrically conductive, anti-adhesion UV-activated composition.

[0052] A fourth aspect of the present invention provides a method for preparing an adhesive film, comprising: coating the electrically conductive and anti-adhesive UV-activated composition onto the surface of a first release film to form a coating, and after drying, covering the surface of the coating with a second release film to obtain the adhesive film.

[0053] In some more specific embodiments, the method for preparing the adhesive film specifically includes the following steps: The UV-activated composition is uniformly coated onto a first release film and baked in an oven at 110°C for 3 minutes to form an adhesive layer. After it is completely dry, a second release film is then coated onto the surface of the UV-activated composition to obtain the adhesive film.

[0054] A fifth aspect of the present invention provides an adhesive tape comprising a substrate layer, an adhesive layer coated on the surface of the substrate layer, and a release layer disposed on the adhesive layer; said adhesive layer is formed from the electrically conductive, anti-adhesive UV-activated composition.

[0055] Furthermore, the substrate layer includes a release film.

[0056] An exemplary schematic diagram of the adhesive film structure in a typical embodiment of the present invention is shown below. Figure 1 As shown, the adhesive film includes a second release film layer 1, an adhesive layer 2, and a first release film layer 3.

[0057] An exemplary schematic diagram of the tape structure in a typical embodiment of the present invention is shown below. Figure 2 As shown, the UV-activated epoxy tape includes a release film layer 4, an adhesive layer 5, and a substrate layer 6.

[0058] A sixth aspect of the present invention provides a method for non-destructive disassembly of an adhesive structure, the adhesive structure comprising a first object and a second object fixedly connected by an adhesive layer, the adhesive layer being formed by curing the electrically conductive, anti-adhesion UV-activated composition, and the method comprising: A set current is applied to the adhesive layer for a set duration, causing the conductive network therein to heat up until the temperature of the adhesive layer is equal to or higher than the thermal decomposition temperature or glass transition temperature of the resin component in the adhesive layer, thereby allowing the first object and the second object to separate without damage.

[0059] Furthermore, the curing conditions are: irradiation with a 365nm LED light source at a concentration of 4000~5000mJ / m². 2 25℃ / 50%RH environment.

[0060] In this invention, the bonding strength is controlled by the type, ratio, and degree of curing of the resin, and the heating temperature and rate are precisely controlled by the type, concentration, dispersion state of the conductive filler, as well as the applied voltage, current and energizing time, so as to achieve rapid and controllable viscosity reduction.

[0061] Specifically, the main principle of this invention for non-destructive disassembly of bonded components is as follows: Conductive fillers (such as carbon nanotubes, graphene, carbon black, etc.) are uniformly dispersed in the adhesive film. When electricity is applied, the conductive network generates Joule heating, causing the local temperature of the adhesive layer to rapidly rise above the glass transition temperature or thermal decomposition temperature of the epoxy resin within a short time (e.g., several seconds to tens of seconds). At this point, the cross-linked epoxy network softens or undergoes localized degradation, macroscopically manifested as a sharp decrease in adhesive strength, thereby achieving easy separation.

[0062] In summary, the UV-activated composition, tape, and film for reducing adhesion through electrical conduction provided by this invention can be cured by UV activation to achieve the bonding strength of structural adhesives and semi-structural adhesives, and can also be de-adhesive by applying low-voltage direct current to quickly cause the bonding interface to lose its adhesive force.

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0064] For experiments not specifically described in the examples, the procedures or conditions can be performed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available. Other unmentioned raw materials and instruments are all conventionally chosen and do not involve the core technical means of this invention.

[0065] For example, the specific sources of the raw materials used in the following embodiments and comparative examples of the present invention are shown in Table 1: Table 1

[0066] Example 1 (1) Synthesis of epoxy-modified acrylic resin Methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, azobisisobutyronitrile, and ethyl acetate were thoroughly mixed in a mass ratio of 70:10:5:15:0.5:100. One-third of the mixture was added to a four-necked flask and stirred in a 65°C oil bath under nitrogen protection. The remaining two-thirds of the mixture was added to the four-necked flask by titration over 4 hours. After titration, the mixture was kept at 65°C for 4 hours, then heated to 75°C and kept at 75°C for 1 hour to remove residual monomers. After the reaction was completed, the reaction solution was removed, and a certain amount of ethyl acetate solvent was added to adjust the solid content to 40%, thus obtaining an epoxy-modified acrylic resin solution with a molecular weight of approximately 70,000.

[0067] (2) Preparation of UV-activated epoxy film 25 parts epoxy-modified acrylic resin (unless otherwise specified, all parts are by weight), 13 parts bisphenol A type epoxy resin (5 parts Nanya NPES-901 epoxy resin, 8 parts Nanya NPEL-128 epoxy resin), 5 parts tetrafunctional thiol curing agent, 0.3 parts photoalkalizing agent WPBG-300, 0.5 parts ITX: 2-isopropylthioxanthone, 5 parts lithium trifluoromethanesulfonate, 0.3 parts silane coupling agent, BYK333 Mix 0.1 parts of cellulose acetate butyrate, 4.5 parts of 1010 antioxidant, and conductive powder (conductive powder 1: 20 parts of spherical nickel powder with D50: 11um, conductive powder 2: 20 parts of flaky nickel powder with 300 mesh, and conductive powder 3: 10 parts of chain nickel powder with D50: 0.6um) evenly in the specified proportions, let stand to remove bubbles, and evenly coat it onto the release film. Bake in an oven at 110℃ for 3 minutes. After it is completely dry, cover it with a lighter layer of release film to obtain a film with a thickness of 50μm.

[0068] Example 2 (1) Synthesis of epoxy-modified acrylic resin The preparation method is the same as in Example 1.

[0069] (2) Preparation of UV-activated epoxy film The following ingredients were used: 15 parts epoxy-modified acrylic resin, 10 parts bisphenol A type epoxy resin (5 parts Nanya NPES-901 epoxy resin and 5 parts Nanya NPEL-128 epoxy resin), 2 parts tetrafunctional thiol curing agent, 0.3 parts photoalkali-generating agent WPBG-300, 0.1 parts ITX: 2-isopropylthioxanthone, 2 parts lithium trifluoromethanesulfonate, 0.3 parts silane coupling agent, 0.1 parts BYK333, 2 parts cellulose acetate butyrate, 0.3 parts 1010 antioxidant, and conductive powder (conductive powder 1: 20 parts D50: 11um spherical nickel powder, conductive powder 2: 20 parts 300 mesh flake copper powder, conductive powder 3: 10 parts D50: 0.6um chain silver powder). The remaining steps were the same as in Example 1.

[0070] Example 3 (1) Synthesis of epoxy-modified acrylic resin The preparation method is the same as in Example 1.

[0071] (2) Preparation of UV-activated epoxy film The following ingredients were used: 35 parts epoxy-modified acrylic resin, 20 parts bisphenol A type epoxy resin (10 parts Nanya NPES-901 epoxy resin and 10 parts Nanya NPEL-128 epoxy resin), 8 parts tetrafunctional thiol curing agent, 0.3 parts photoalkali-generating agent WPBG-300, 0.5 parts ITX: 2-isopropylthioxanthone, 8 parts lithium trifluoromethanesulfonate, 0.3 parts silane coupling agent, 0.1 parts BYK333, 4.5 parts cellulose acetate butyrate, 0.3 parts 1010 antioxidant, and 50 parts conductive carbon nanotube powder. The remaining steps were the same as in Example 1.

[0072] Example 4 (1) Synthesis of epoxy-modified acrylic resin The preparation method is the same as in Example 1.

[0073] (2) Preparation of UV-activated epoxy film The following ingredients were used: 25 parts epoxy-modified acrylic resin, 13 parts bisphenol A type epoxy resin (5 parts Nanya NPES-901 epoxy resin and 8 parts Nanya NPEL-128 epoxy resin), 5 parts trimethylolpropane trimercaptoacetate curing agent, 0.3 parts photoalkali-generating agent WPBG-300, 0.5 parts ITX:2-isopropylthioxanthone, 5 parts potassium perfluorooctyl sulfonate, 0.3 parts silane coupling agent, 0.1 parts BYK333, 4.5 parts fumed silica, 0.3 parts 1010 antioxidant, and 30 parts conductive graphene powder. The remaining steps were the same as in Example 1.

[0074] Example 5 (1) Synthesis of epoxy-modified acrylic resin The preparation method is the same as in Example 1.

[0075] (2) Preparation of UV-activated epoxy film The following ingredients were used: 25 parts epoxy-modified acrylic resin, 13 parts bisphenol A type epoxy resin (5 parts Nanya NPES-901 epoxy resin and 8 parts Nanya NPEL-128 epoxy resin), 5 parts pentaerythritol tetrakis(3-mercaptobutyric acid) curing agent, 0.3 parts diphenyliodonium hexafluorophosphate photoinitiator, 0.5 parts ITX: 2-isopropylthioxanthraquinone, 5 parts potassium perfluorooctyl sulfonate, 0.3 parts silane coupling agent, 0.1 parts BYK333, 4.5 parts cellulose acetate butyrate, 0.3 parts 1010 antioxidant, and 50 parts conductive carbon black. The remaining steps were the same as in Example 1.

[0076] Comparative Example 1 (2) Preparation of UV-activated epoxy film No epoxy-modified acrylic resin was added; otherwise, it was the same as in Example 1.

[0077] Comparative Example 2 (2) Preparation of UV-activated epoxy film No curing agent was added; otherwise, it was the same as in Example 1.

[0078] Comparative Example 3 (2) Preparation of UV-activated epoxy film No conductive filler was added; otherwise, it was the same as in Example 1.

[0079] Comparative Example 4 (1) Synthesis of epoxy-modified acrylic resin The ingredients are methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, azobisisobutyronitrile, and ethyl acetate, in a mass ratio of 85:10:5:0:0.5:100.

[0080] The remaining process conditions were the same as in Example 1, resulting in an epoxy-modified acrylic resin solution with a molecular weight of approximately 56,000.

[0081] (2) Preparation of UV-activated epoxy film No photoinitiator was added; otherwise, it was the same as in Example 1.

[0082] Comparative Example 5 (1) Synthesis of epoxy-modified acrylic resin The ingredients are methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, glycidyl methacrylate, azobisisobutyronitrile, and ethyl acetate, in a mass ratio of 65:10:5:20:0.5:100.

[0083] The remaining process conditions were the same as in Example 1, resulting in an epoxy-modified acrylic resin solution with a molecular weight of approximately 33,000.

[0084] (2) Preparation of UV-activated epoxy film Same as Example 1.

[0085] Comparative Example 6 (1) Synthesis of epoxy-modified acrylic resin The ingredients are methyl acrylate, acrylonitrile, 2-hydroxyethyl acrylate, glycidyl methacrylate, azobisisobutyronitrile, and ethyl acetate, in a mass ratio of 70:10:5:15:0.5:100.

[0086] The remaining process conditions were the same as in Example 1, resulting in an epoxy-modified acrylic resin solution with a molecular weight of approximately 89,000.

[0087] (2) Preparation of UV-activated epoxy film Same as Example 1.

[0088] Comparative Example 7 (1) Synthesis of epoxy-modified acrylic resin Methyl acrylate, butyl acrylate, glycidyl methacrylate, azobisisobutyronitrile and ethyl acetate, in a mass ratio of 75:10:15:0.5:100.

[0089] The remaining process conditions were the same as in Example 1, resulting in an epoxy-modified acrylic resin solution with a molecular weight of approximately 76,000.

[0090] (2) Preparation of UV-activated epoxy film Same as Example 1.

[0091] Performance testing The films of Examples 1-6 and Comparative Examples 1-5 of the present invention were subjected to performance tests such as conductivity, dynamic shear strength, high temperature holding force, and current density. The test results are shown in Table 2.

[0092] The specific testing method is as follows: During the bonding process, the adhesive films of the examples and comparative examples were cured under UV light to obtain the adhesive layer. The curing conditions for the adhesive films were: 365nm LED light source irradiation at 4000~5000 mJ / m². 2 25℃ / 50%RH environment.

[0093] A set voltage is applied to the adhesive layer for a set duration, with the energizing conditions being 30V / 30s and a current density of 27 mA / cm². 2 This causes the conductive network within the adhesive layer to heat up until the temperature of the adhesive layer is equal to or higher than the thermal decomposition temperature or glass transition temperature of the resin component in the adhesive layer, thereby achieving non-destructive separation between objects.

[0094] The adhesive film of Example 1 was subjected to different electrostatic de-adhesion conditions, with the electrostatic conditions changed to 10V / 60s and the current density to 26mA / cm². 2 The test results are shown in Table 2.

[0095] Conductivity test (s / cm): The adhesive film was laminated to a 20 μm thick copper foil and tested according to ASTM D4496 standard.

[0096] Dynamic shear strength (MPa): The two sides of the adhesive film were bonded to a 20 μm thick copper foil and a 2 mm thick aluminum foil, respectively. The measurements were taken before and after energization, according to ASTM D1002 and GB / T 33332-2016 standards.

[0097] High-temperature holding power (H): The adhesive film is attached to a 304 steel plate and tested according to ASTM D3654 standard. The test measures the high-temperature holding power at 100°C without power.

[0098] Current density (mA / cm) 2The testing standard is JJG843.

[0099] Table 2 Performance Test Results Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Power on conditions 30V / 30S 10V / 60S 30V / 30S 30V / 30S 30V / 30S 30V / 30S 30V / 30S / 30V / 30S / 30V / 30S 30V / 30S 30V / 30S Conductivity test (s / cm) 7.83 x 10 -4 ]] 7.76 x 10 -4 ]] 7.29 x 10 -4 ]] 6.64 x 10 -4 ]] 7.31 x 10 -4 ]] 7.08 x 10 -4 ]] / / 3.21 x 10 -13 ]] / 7.28 x 10 -4 ]] 7.94 x 10 -4 ]] 7.19 x 10 -4 ]] Dynamic shear strength before power on (Mpa) 8.83 8.81 8.12 10.2 8.42 7.18 / / 17.65 / 4.23 3.89 3.45 Dynamic shear strength after power on (Mpa) 0.07 3.87 0.06 1.29 0.08 1.73 / / 17.73 / 0.04 0.08 0.06 High temperature retention H (without power on) ＞72 ＞72 ＞72 ＞72 ＞72 ＞72 / / ＞72 / ＞72 ＞72 ＞72 Current density (mA / cm 2 ) 27 26 24 17 28 25 / / 8 / 23 21 　 / The results from the above embodiments and comparative examples show that Embodiment 1 is the optimal technical solution with the best technical effect.

[0100] This invention also evaluates the impact of different electrostatic tack reduction conditions on adhesive film products. It can be seen that the final performance results of the adhesive film are similar regardless of the electrostatic tack reduction conditions.

[0101] Comparative Example 1 primarily evaluates the impact of unsynthesized epoxy-modified acrylic resin on the final product's performance. It can be seen that the film-forming properties are too poor, and the film is too brittle to be tested.

[0102] Comparative Example 2 primarily evaluates the impact of not adding a thiol curing agent on the performance of the final adhesive film product, which does not cure.

[0103] Comparative Example 3 mainly evaluates the impact of not adding conductive fillers on the performance of the adhesive film product. It can be seen that without the addition of conductive powder, the adhesion is higher, but the conductivity is lost.

[0104] Comparative Example 4 mainly evaluates the impact of the absence of GMA and photoinitiator in the technical solution on the final product. It can be seen that the synthesis part is incompatible with other components.

[0105] Comparative Example 5 mainly evaluated the effect of excessive GMA addition in the epoxy-modified acrylic resin component on the adhesive film product. The final adhesive film was harder, which affected the wettability with the substrate and reduced the bonding performance.

[0106] Comparative Example 6 mainly evaluates the impact of the replacement raw materials in the technical solution on the performance of the adhesive film product. It can be seen that the introduction of acrylonitrile increases the modulus of the product (the product becomes harder) and reduces the adhesion to the substrate.

[0107] Comparative Example 7 was mainly used to evaluate the effect of not adding 2-HEA monomer on the adhesive film product. It can be seen that the initial tack of the adhesive film product is reduced, the wettability with the substrate is reduced, and the final bonding performance is affected.

[0108] All aspects, embodiments, features, and examples of this invention should be considered illustrative in all respects and are not intended to limit the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention.

[0109] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0110] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A UV-activated composition capable of reducing viscosity through electrical conduction, characterized in that, It includes the following components by weight: 15-35 parts epoxy-modified acrylic resin, 10-20 parts epoxy resin, 0.1-0.5 parts photoinitiator, 0.2-1 parts photosensitizer, and 30-80 parts conductive filler; Furthermore, the UV-activated composition satisfies the following conditions: a) When the UV-activated composition is cured to form a film, the conductive filler is able to form a conductive network in the film, and the conductive network is able to generate heat when energized; b) The thermal decomposition temperature or glass transition temperature of the resin component in the film is lower than or equal to the temperature of the conductive network after a set current is applied and the current is maintained for a set duration.

2. The electrically conductive, non-sticky UV-activated composition according to claim 1, characterized in that, The UV-activated composition further includes the following components calculated by weight: 2-8 parts curing agent, 2-8 parts thickener, and 2-8 parts solid conductive salt; And / or, the UV-activated composition may further include optional additives, including toughening agents, leveling agents, or coupling agents.

3. The electrically conductive, non-sticky UV-activated composition according to claim 1, characterized in that, The preparation method of the epoxy-modified acrylic resin includes: reacting a first reactive monomer and a second reactive monomer at 60~80°C in the presence of a free initiator to obtain the epoxy-modified acrylic resin, wherein the first reactive monomer contains an acrylic structural unit and the second reactive monomer is selected from ester substances; Preferably, the first reactive monomer comprises one or more of methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, and tetrahydrofuran methacrylate; Particularly preferred is that the first reactive monomer comprises a combination of methyl acrylate, butyl acrylate and 2-hydroxyethyl acrylate; Preferably, the second reactive monomer comprises glycidyl methacrylate; Particularly preferred is that the mass ratio of methyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate and glycidyl methacrylate is 60~90:10~20:2~8:10~20; Preferably, the free radical initiator comprises azobisisobutyronitrile; Preferably, the reaction is carried out in a solvent, including ethyl acetate; And / or, the number average molecular weight of the epoxy-modified acrylic resin is 40,000 to 200,000.

4. The electrically conductive, non-sticky UV-activated composition according to claim 2, characterized in that, The epoxy resin includes any one or a combination of several of the following: bisphenol A type epoxy resin, phenolic modified epoxy resin, amino epoxy resin, and aliphatic epoxy resin. And / or, the photosensitizer includes any one or a combination of several of the following: iodonium salts, fluorenes, fluorenones, anthraquinones, anthrones, fluoranthenes, and benzyl ketals; Preferably, the photosensitizer comprises 2-isopropylthioxanthraquinone; And / or, the photoinitiator comprises any one or a combination of several of the following: diphenyliodonium chloride, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, and tetraphenylborate. And / or, the curing agent is a thiol-based epoxy curing agent, the curing agent comprising at least one of trimethylolpropane trimercaptoacetate, tetra(3-mercaptopropionic acid) ester, pentaerythritol tetra(3-mercaptobutyrate) ester, and hexafunctional thiols; And / or, the solid conductive salt is an organic sulfonate containing an alkali metal, and the solid conductive salt includes at least one of lithium trifluoromethanesulfonate and potassium perfluorooctyl sulfonate; And / or, the thickener includes any one or a combination of several of fumed silica and cellulose; And / or, the conductive filler includes any one or a combination of several of the following: nickel powder, copper powder, silver powder, carbon nanotubes, graphene, and carbon black; Preferably, the conductive filler is in the shape of spheres, sheets, or chains.

5. The method for preparing the electrically conductive, non-adhesive UV-activated composition according to any one of claims 1-4, characterized in that, include: We provide epoxy-modified acrylic resins; The UV-activated composition is prepared by uniformly mixing the epoxy-modified acrylic resin, epoxy resin, photoinitiator, and conductive filler.

6. A film, characterized in that, The adhesive film is formed from the UV-activated composition for reducing adhesion as described in any one of claims 1-4.

7. A method for preparing an adhesive film, characterized in that, include: The UV-activated composition capable of reducing adhesion by electrical conduction, as described in any one of claims 1-4, is coated onto the surface of a first release film to form a coating. After drying, a second release film is applied to the surface of the coating to obtain the adhesive film.

8. An adhesive tape, comprising a substrate layer, an adhesive layer coated on the surface of the substrate layer, and a release layer disposed on the adhesive layer; characterized in that: The adhesive layer is formed from the electrically conductive, anti-adhesion UV-activated composition according to any one of claims 1-4.

9. The tape according to claim 8, characterized in that: The substrate layer includes a release film.

10. A method for non-destructive disassembly of an adhesive structure, the adhesive structure comprising a first object and a second object fixedly connected by an adhesive layer, characterized in that... The adhesive layer is formed by curing the electrically conductive, anti-adhesion UV-activated composition according to any one of claims 1-4, and the method comprises: A set current is applied to the adhesive layer for a set duration, causing the conductive network therein to heat up until the temperature of the adhesive layer is equal to or higher than the thermal decomposition temperature or glass transition temperature of the resin component in the adhesive layer, thereby allowing the first object and the second object to separate without damage.

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