Magnetic conductive adhesive tape capable of reducing viscosity after being electrified

Abstract

The invention relates to a power-on viscosity-reducing magnetic conductive adhesive tape which comprises a magnetic conductive shielding functional layer, an adhesive layer, a power-on viscosity-reducing adhesive layer and a release layer. The magnetic conductive shielding functional layer takes a copper foil as a base material, a magnetic conductive adhesive is coated on the copper foil, the magnetic conductive adhesive comprises a magnetic conductive filler, epoxy resin, an acrylate monomer and ethyl acetate, and the adhesive layer comprises an acrylate monomer, ethyl acetate, epoxy resin and polyetherimide. The electrified visbreaking adhesive layer comprises an acrylate monomer, ethyl acetate, epoxy resin, solid conducting salt, a polar proton inert solvent, methoxy polyethylene glycol and a coupling agent. According to the adhesive tape, a conductive layer and an adhesive layer can be additionally arranged between the electrified visbreaking adhesive layer and the release layer, and the magnetic conductive shielding functional layer and the conductive layer are both provided with conductive interface connecting ends. The adhesive tape has the functions of magnetic conduction shielding and power-on visbreaking, and is suitable for electromagnetic shielding and conductive bonding of electronic equipment.

Description

Technical Field

[0001] The present invention provides a magneto-conductive tape with reduced adhesion upon energization, belonging to the technical field of magneto-conductive shielding tapes. Background Art

[0002] At present, in a high-frequency environment, the demand for magneto-conductive shielding tapes in electronic products is increasing. Compared with other ordinary adhesive tapes, magneto-conductive shielding tapes have more magneto-conductive fillers, and these fillers account for most of the cost of magneto-conductive shielding tapes. Existing magneto-conductive shielding tapes can already meet the adhesion requirements, but it is difficult to tear them off during the repair and recycling of electronic devices, which affects work efficiency. Generally, in order to tear off the tape, hot air is blown on the tape, but this will damage sensitive components, and it is still easy to leave marks when tearing off the tape. In addition, the magnetic conduction efficiency of the tape will also be affected by electromagnetic wave interference. How to reduce electromagnetic wave interference is also a problem that needs to be solved.

[0003] Existing patents such as those with publication numbers CN 109705759 B and CN 110105892 B affect the tape adhesion by emitting light or generating heat after energization, but the adhesion of the tape decreases significantly when used again. For exclusive tapes with customized shapes and specifications, if they are replaced after being removed, it will cause an increase in cost and waste of materials. Summary of the Invention

[0004] The present invention provides a magneto-conductive tape with reduced adhesion upon energization to improve the shielding performance of the tape and solve the problem of difficult recycling and reuse of magneto-conductive shielding tapes;

[0005] A magneto-conductive tape with reduced adhesion upon energization provided by the present invention, the tape includes: a magneto-conductive shielding functional layer, an adhesive layer, an adhesive layer with reduced adhesion upon energization, and a release layer. Among them, the magneto-conductive shielding functional layer is the base layer, and the magneto-conductive shielding functional layer is connected to the adhesive layer; the adhesive layer with reduced adhesion upon energization is connected to the adhesive layer, and the adhesive layer with reduced adhesion upon energization is attached to the release layer.

[0006] Further, the base material of the magneto-conductive shielding functional layer 1 is copper foil, and a magneto-conductive adhesive is coated on the copper foil. The mass material ratio composition of the magneto-conductive adhesive includes: 10 - 30 parts of magneto-conductive filler, 30 - 50 parts of epoxy resin, 40 - 60 parts of acrylate monomer, and 30 - 50 parts of ethyl acetate.

[0007] Further, the magneto-conductive filler includes at least one of cobalt-nickel ferrite and nano-scale iron, cobalt, and nickel.

[0008] Further, the mass material ratio composition of the adhesive layer material includes: 50 - 80 parts of acrylate monomer, 20 - 30 parts of ethyl acetate, 20 - 30 parts of epoxy resin, and 3 - 5 parts of polyetherimide;

[0009] Furthermore, the epoxy resin is bisphenol S type epoxy resin.

[0010] Furthermore, the mass ratio composition of the electroconductive viscosity-reducing adhesive layer includes: 60 - 80 parts of acrylate monomer, 30 - 50 parts of ethyl acetate, 20 - 30 parts of epoxy resin, 20 - 40 parts of solid conductive salt, 20 - 40 parts of polar aprotic inert solvent, 10 - 20 parts of methoxypolyethylene glycol, and 1 - 5 parts of coupling agent;

[0011] Furthermore, the composition of the solid conductive salt includes one or more of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, and lithium trifluoromethanesulfonate;

[0012] Furthermore, the composition of the polar aprotic inert solvent includes one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), hexamethylphosphoramide (HMPA), acetonitrile (ACN), tetrahydrofuran (THF), and acetone;

[0013] Furthermore, when the adhering object is an insulating surface, there is also a conductive layer and an adhesive layer coated between the conductive layer and the release layer between the electroconductive viscosity-reducing adhesive layer and the release layer;

[0014] Furthermore, both the base layer and the conductive layer are provided with conductive interface connection ends.

[0015] Advantages of the present invention:

[0016] By providing an electroconductive viscosity-reducing adhesive layer, a base layer, and a conductive layer, and performing short-term energization during tape tearing, the viscosity can be quickly reduced to achieve traceless tearing;

[0017] By providing an adhesive layer in the electroconductive viscosity-reducing adhesive layer and the base layer, it can prevent the base layer from reducing viscosity after energization and achieve directional viscosity-reducing tearing;

[0018] Using a solid conductive salt and a polar aprotic inert solvent in the electroconductive viscosity-reducing adhesive layer enables ion movement between the upper and lower layers of the tape, achieving the viscosity reduction effect between the electroconductive viscosity-reducing adhesive layer and the adhering surface;

[0019] By using a magnetic conduction filler and a solid conductive salt, the shielding effectiveness can be significantly increased, the conductive effect can be improved, and the skin effect can be reduced;

[0020] By adding methoxypolyethylene glycol to the viscosity-reducing adhesive layer, it can simultaneously act as an emulsifier, a dispersant, a thickener, and an electrolyte, with obvious effects, achieving cost reduction and efficiency improvement. Description of the Drawings

[0021] Figure 1 It is the hierarchical structure diagram of Embodiment 1 of the product of the present invention;

[0022] Figure 2 Hierarchical structure diagram of Embodiment 2 of the product of the present invention;

[0023] Figure 3 Hierarchical structure diagram of Embodiment 3 of the product of the present invention;

[0024] Wherein:

[0025] 1. Magnetic conduction shielding functional layer; 2. Adhesive layer; 3. Electrically conductive viscosity-reducing adhesive layer; 4. Release layer; 5. Conductive layer. Detailed implementation manners

[0026] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0027] Many specific details are set forth in the following description in order to fully understand the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0029] An electrically conductive viscosity-reducing magnetic conduction tape, the hierarchical structure of which includes: a magnetic conduction shielding functional layer 1, an adhesive layer 2, an electrically conductive viscosity-reducing adhesive layer 3, and a release layer 4. The magnetic conduction shielding functional layer 1 is the base layer, and the magnetic conduction shielding functional layer 1 is connected to the adhesive layer 2; the electrically conductive viscosity-reducing adhesive layer 3 is connected to the adhesive layer 2, and the electrically conductive viscosity-reducing adhesive layer 3 is attached to the release layer 4. The release layer is a polyester film coated with a silicone oil release agent. When the attachment surface is a conductive surface, the hierarchical structure can be attached to the conductive surface to achieve a shielding effect. The positive and negative electrodes of the power supply are respectively connected to the connection ends of the base layer and the conductive surface. When energized at 10V for 30 seconds, the conductive surface and the tape's electrically conductive viscosity-reducing layer can be separated;

[0030] The base material of the magnetic conduction shielding functional layer 1 is copper foil, and a magnetic conduction adhesive is coated on the copper foil. The mass ratio composition of the magnetic conduction adhesive includes: 10 - 30 parts of magnetic conduction filler, 30 - 50 parts of epoxy resin, 40 - 60 parts of acrylate monomer, and 30 - 50 parts of ethyl acetate. In this embodiment, the epoxy resin is bisphenol S type epoxy resin, specifically bisphenol S diglycidyl ether;

[0031] The magneto-conductive adhesive material is placed in a reactor at 60 - 80 °C and stirred. When the adhesive material is completely polymerized, the magneto-conductive adhesive is obtained. The adhesive is coated on the substrate by a comma coating knife, and the coating thickness is 20 - 50 μm. Then the tape is sent into a curing oven for curing. The curing temperature has 7 segments, and the curing temperatures are 100 °C, 120 °C, 140 °C, 160 °C, 140 °C, 120 °C, and 100 °C respectively. The curing time for each segment is 20 - 40 s. After curing, it is wound up to obtain the coil 1;

[0032] The magneto-conductive filler in the magneto-conductive adhesive material includes at least one of cobalt-nickel ferrite, nano-scale iron, cobalt, and nickel.

[0033] The cobalt-nickel ferrite is self-produced. The materials used include cobalt nitrate, nickel nitrate, and iron nitrate. Cobalt nitrate, nickel nitrate, and iron nitrate are mixed according to the molar ratio of 1:2:2. The weighed nitrates are dissolved in an appropriate amount of deionized water and heated to 40 - 50 °C under stirring, so that the pH value of the solution is between 1 and 2;

[0034] Then citric acid is added to the solution as a complexing agent, and its dosage should be slightly higher than 10% of the cation substance amount. Using citric acid helps the metal ions to form complexes, so as to be evenly distributed in the subsequent steps;

[0035] Then an appropriate amount of ethylenediamine is added to adjust the pH value of the solution to 7 to ensure that the metal ions are fully complexed with citric acid to form a stable sol;

[0036] Then the solution is continuously heated and stirred until most of the water evaporates and the solution becomes thick to form a uniform sol;

[0037] Then the thick sol is poured into a porcelain dish and heated on an electric furnace until it burns. During the burning process, an exothermic reaction occurs between citric acid and nitrate to form a preliminary oxide powder;

[0038] Then the burned ash is collected and calcined in a high-temperature furnace at 800 °C for 2 hours to form pure cobalt-nickel ferrite. The particle size of the cobalt-nickel ferrite obtained in this example is 400 - 600 nm.

[0039] The nano-scale magnetic iron, cobalt, and nickel are also self-prepared. Commonly used metal salts containing the above metals are selected, including nitrates, chlorides, sulfates, etc. The solvent used is polyol, and the polyol includes ethylene glycol and glycerol. The metal salts are dissolved in the polyol, and a uniform reaction solution is formed after complete dissolution.

[0040] The polyol solution containing metal salts is heated to between 150 °C and 200 °C. During this process, the polyol will reduce the metal salts to generate metal nanoparticles;

[0041] After the reaction is completed, cool the reaction system to room temperature to precipitate the nanoparticles;

[0042] Wash the precipitate with acetone to remove excess polyol and other by-products, and then dry the washed precipitate to obtain pure metal nanoparticles. The particle size of the nanoparticles in this example is 10 - 50 nm.

[0043] The mass ratio composition of the adhesive layer 2 material includes: 50 - 80 parts of acrylate monomer, 20 - 30 parts of ethyl acetate, 20 - 30 parts of epoxy resin, and 3 - 5 parts of polyetherimide; mix the adhesive layer materials and place them in a reaction kettle at 40 - 60 °C for stirring. When the materials are evenly mixed and polymerized completely, the adhesive is obtained. Coating the adhesive on the web 1 with a comma coating knife, the coating thickness is 10 - 20 μm. Then, send the tape into a curing oven for curing. The curing temperature is 7 segments, and the curing temperatures are 80 °C, 100 °C, 120 °C, 130 °C, 120 °C, 100 °C, and 80 °C respectively. The curing time for each segment is 10 - 15 s. After curing, wind up to obtain the web 2;

[0044] The mass ratio composition of the electrically conductive adhesive layer material for the tape includes: 60 - 80 parts of acrylate monomer, 30 - 50 parts of ethyl acetate with a purity of more than 95%, 20 - 30 parts of epoxy resin, 20 - 40 parts of solid conductive salt, 20 - 40 parts of polar aprotic solvent, 10 - 20 parts of methoxypolyethylene glycol, and 1 - 5 parts of coupling agent. Methoxypolyethylene glycol acts as an emulsifier, dispersant, thickener, and electrolyte in the material mixture. The coupling agent is a silane coupling agent or a titanate coupling agent, specifically γ-aminopropyltriethoxysilane and tetra-isopropyl titanate. γ-aminopropyltriethoxysilane is used to improve the interfacial bonding force between the adhesive and the substrate and increase the bonding strength, while tetra-isopropyl titanate can also improve the interfacial properties and enhance the water resistance and chemical resistance of the adhesive.

[0045] The composition of the solid conductive salt in the electrically conductive adhesive layer includes one or more of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, and lithium trifluoromethanesulfonate. In this example, lithium bis(trifluoromethylsulfonyl)imide is selected, and the particle size of the solid conductive salt is 0.6 μm - 1 μm.

[0046] The composition of the polar aprotic solvent in the electrically conductive adhesive layer includes one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), hexamethylphosphoramide (HMPA), acetonitrile (ACN), tetrahydrofuran (THF), and acetone. In this example, N-methylpyrrolidone (NMP) is selected.

[0047] Put the electrically conductive tack-reducing adhesive layer material into a reaction kettle at 80 - 90 °C and stir. When the material is evenly mixed and polymerized completely, the electrically conductive tack-reducing adhesive is obtained. Coat this adhesive on the coil 2 through a comma coater blade, with a coating thickness of 30 - 50 μm. Then send the tape into a curing oven for curing. The curing temperature is divided into 5 sections, and the curing temperatures are 90 °C, 110 °C, 130 °C, 110 °C, and 90 °C respectively. The curing time for each section is 30 - 50 s. After curing, wind it up to obtain coil 3;

[0048] After laminating coil 3 with the release layer, wind it up to obtain the tape of this embodiment, and cut it as needed during use.

[0049] Example 2

[0050] The difference from Example 1 is that when the adherend is an insulating surface, there is also a conductive layer 5 and an adhesive layer coated between the conductive layer and the release layer 4 between the electrically conductive tack-reducing adhesive layer 3 and the release layer 4. Both the base layer and the conductive layer are provided with conductive interface connection ends for convenient power connection. The conductive layer is a conductive copper foil. This hierarchical structure enables the tape to adapt to both conductive and insulating adherends simultaneously, increasing the applicable environment of the tape.

[0051] Both the base copper foil and the conductive layer are provided with conductive interface connection ends for convenient external power connection. The connection ends are respectively connected to the positive and negative poles of the power supply. When powered on at 10 V for 30 seconds, the conductive surface and the electrically conductive tack-reducing layer of the tape can be separated, realizing the simultaneous adaptation to conductive and insulating adherends.

[0052] Example 3

[0053] The difference from Example 1 is that to facilitate the selection of the tape sticking surface and the electrically conductive tack-reducing surface, an adhesive layer and a release layer are also provided on the copper foil surface of the magnetic conduction shielding functional layer, forming a double-sided tape for fixing the tape on a specific surface and performing electrically conductive tack reduction on the surface that needs tack reduction.

[0054] The epoxy resin, acrylate monomer, ethyl acetate, acetone, alcohols, polyetherimide, and coupling agent used in the examples of the present invention were purchased from Zhejiang Yuanbang Material Technology Co., Ltd., and other reagents were purchased from Sigma-Aldrich Company (Merck reagents).

[0055] Taking the products of Example 1, Example 2, and Example 3 as the control group, data tests were carried out together with the following comparative tapes. Comparative Example 1, the difference from Example 2 is that the copper foil in the magnetic conduction shielding functional layer is replaced by a film cured from conductive ink;

[0056] Comparative Example 2, the difference from Example 2 is that the magnetic conduction shielding functional layer is directly bonded to the electrically conductive tack-reducing adhesive layer;

[0057] Comparative Example 3, which is different from Example 2 in that the filler in the magnetic conduction shielding functional layer has a particle size of 1-10 um;

[0058] Comparative Example 4, a Chinese patent application with the publication number CN 110105892 B;

[0059] Comparative Example 5, a Chinese patent application with the publication number CN 110105892 B;

[0060] Test content

[0061] Electromagnetic shielding performance test, which is carried out by adopting the measurement method of material shielding effectiveness in SJ20524-1995;

[0062] Magnetic permeability performance test: Use the MICROTEST magnetic permeability tester 6632-50, intercept a sample of 25mm * 25mm, test it in an environment of T = 22 ± 5 °C and RH = 55 ± 10%, put the test tape into the tester, adjust the test instrument, set the test frequency to 10 kHz, and read the initial magnetic permeability data and the maximum magnetic permeability data.

[0063] Flex resistance test: Select tempered glass with a thickness of 5.0 mm, intercept a sample of 14 mm * 5 mm, stack two pieces of tempered glass horizontally, take a sample of the magnetic conduction double-sided tape, evenly attach it to the surfaces and sides of the two pieces of tempered glass, perform a 90-degree bending attachment, keep it at room temperature for 1 week, and observe whether the connection of the tempered glass warps every day.

[0064] Peel strength test, in an environment of T = 22 ± 5 °C and RH = 55 ± 10%, take a section of the tape to be tested with a width of 25 mm, roll it back and forth twice on the stainless steel test surface with a roller, with a peel angle of 180 degrees and a speed of 300 mm / min, and perform the peel strength test;

[0065] Adhesion performance test, in an environment of T = 22 ± 5 °C and RH = 55 ± 10%, take a section of the tape to be tested with a size of 180 * 20 mm, attach the tape to one side of a 200x30x2 mm PC board and roll it back and forth once with a 2 kg roller, then let it stand for 24 hours, place the PC board with the attached tape on a 190 mm fixture to fix and bend the material, and observe the floating situation at the end after 10 days at room temperature.

[0066] Power-on de-adhesion performance test, in an environment of T = 22 ± 5 °C and RH = 55 ± 10%, take a section of the tape to be tested with a width of 25 mm and attach it to a stainless steel plate, roll it back and forth twice with a roller, connect the extended end of the tape to the positive pole of the power supply, connect the un-taped part of the stainless steel plate to the negative pole of the power supply, apply a voltage of 10 V for 30 seconds, with a peel angle of 180 degrees and a speed of 300 mm / min, perform the peel strength test, and record whether there is residual glue.

[0067] For the energized tack reduction repeatability test, the tape with energized tack reduction performance is peeled off after being energized and then left for 2 hours. Then, the energized tack reduction performance test is performed again, and the result is compared with the initial test result. Repeat the above steps of energization treatment, recovery, and retesting for multiple cycles until the peel force is less than 60% of the initial peel force, and record the number of cycles.

[0068]

[0069] In this article, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. A magnetic conductive tape with electrical viscosity reduction, characterized in that: The adhesive tape comprises: a magnetic permeability shielding functional layer (1), an adhesive layer (2), an electrically de-viscous adhesive layer (3), and a release layer (4), wherein the magnetic permeability shielding functional layer (1) is a base layer, the magnetic permeability shielding functional layer (1) is connected to the adhesive layer (2); the electrically de-viscous adhesive layer (3) is connected to the adhesive layer (2), and the electrically de-viscous adhesive layer (3) is bonded to the release layer (4).

2. A magnetic conductive tape with electrical viscosity reduction as claimed in claim 1, characterized in that: The substrate of the magnetic conductive shielding functional layer (1) is a copper foil, on which a magnetic conductive adhesive is coated. The magnetic conductive adhesive comprises by weight: 10-30 parts of a magnetic conductive filler, 30-50 parts of an epoxy resin, 40-60 parts of an acrylate monomer, and 30-50 parts of ethyl acetate.

3. A magnetic conductive tape with electrical viscosity reduction as claimed in claim 2, characterized in that: The magnetic conductive filler includes cobalt-nickel ferrite and at least one of nano-sized iron, cobalt and nickel.

4. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 1, characterized in that: The adhesive layer (2) comprises, by weight, 50-80 parts of acrylic acid ester monomer, 20-30 parts of ethyl acetate, 20-30 parts of epoxy resin, and 3-5 parts of polyetherimide.

5. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 4, characterized in that: The epoxy resin is bisphenol S type epoxy resin.

6. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 1, characterized in that: The material composition of the electrification viscosity-reducing adhesive layer includes: 60-80 parts of acrylate monomer, 30-50 parts of ethyl acetate, 20-30 parts of epoxy resin, 20-40 parts of solid conductive salt, 20-40 parts of polar aprotic solvent, 10-20 parts of methoxy polyethylene glycol and 1-5 parts of coupling agent.

7. A magnetic conductive tape with electrical viscosity reduction as claimed in claim 6, characterized in that: The solid conductive salt composition includes at least one of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate and lithium trifluoromethanesulfonate.

8. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 7, characterized in that: The polar aprotic solvent composition comprises: N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), hexamethylphosphoramide (HMPA), acetonitrile (ACN), tetrahydrofuran (THF) and acetone, one or more thereof.

9. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 1, characterized in that: There is a conductive layer (5) between the electrically conductive de-viscous adhesive layer (3) and the release layer (4), and an adhesive layer coated between the conductive layer and the release layer (4).

10. The magnetic conductive tape with electrical viscosity reduction as claimed in claim 9, characterized in that: The base layer and the conductive layer are both provided with conductive interface connection terminals.

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