Graphene reinforced emi shielding epdm based tape and method of making

Abstract

The application provides a ternary ethylene propylene rubber-based graphene-reinforced EMI shielding adhesive tape and a preparation method, relates to the technical field of electromagnetic shielding materials, and the adhesive tape comprises an interface impedance modulation layer, a spectrum coding graphene dissipation layer, a ternary ethylene propylene rubber-based strain decoupling support layer, a ternary ethylene propylene rubber modified pressure selective grounding layer and a release protective layer. The spectrum coding graphene dissipation layer is integrally formed by partitioned laser reduction of a graphene oxide composite precursor film, and a non-periodic graphene coding unit is arranged in the interior. The graphene coding unit comprises a low-resistance graphene ring current edge, a semi-reduced graphene dissipation neck, an oxidized graphene spacing area, a nanophase lag dissipation junction and a grounding coupling tail end. During preparation, coding weights are generated according to interference spectrum data of a region to be shielded, and are converted into graphene coding unit sizes, nanogap widths, dissipation neck square resistances and graphene micro-arch bridge densities, and then are formed by roll-to-roll laser reduction and micro-arch bridge compounding.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials technology, specifically to EPDM rubber-based graphene-reinforced EMI shielding tape and its preparation method. Background Technology

[0002] As 5G communication terminals, high-speed optical modules, new energy vehicle electronic control systems, server high-speed interconnect structures, and medical electronic devices develop towards miniaturization, high frequency, and high power density, electromagnetic interference within these devices exhibits characteristics such as concentrated frequency points, spatial localization, limited grounding points, and narrow assembly gaps. Existing metal foil shielding tapes primarily rely on continuous metal layers to reflect electromagnetic waves. While their initial shielding performance is high, when used in enclosed electronic cavities, shielding seams, and around high-speed connectors, reflected electromagnetic waves can create secondary propagation paths within the cavity, leading to local resonance and interference transfer. Existing conductive cloth tapes and voltage-sensitive adhesive tapes typically reduce bulk resistance by increasing the content of metal powder, carbon powder, or graphene fillers. However, high filler content reduces the wettability and peel strength of the pressure-sensitive adhesive, leading to powder shedding at die-cut edges, breakage of the conductive network after bending, and contact resistance drift after damp heat aging.

[0003] Graphene, with its high in-plane conductivity, low density, and good flexibility, is used to prepare lightweight electromagnetic shielding materials. However, traditional graphene shielding tapes typically disperse graphene as a common conductive filler in the adhesive. The spatial orientation, local impedance, thickness-direction grounding path, and high-frequency dissipation location of the graphene sheets are determined by their random dispersion, making it difficult to directionally design based on the interference frequencies, spatial locations of interference, and grounding structures of actual electronic devices. For high-speed signal modules, vehicle electronic control units, and communication terminals, electromagnetic interference consists of specific switching frequencies, harmonic frequencies, signal edge frequencies, cavity resonant frequencies, and cable coupling frequencies. If the shielding material cannot be structurally designed to address these spectral characteristics, it requires repeated trials with different thicknesses, metallization levels, and combinations of absorbing materials, resulting in long development cycles and poor consistency.

[0004] To address the aforementioned issues, a novel EMI shielding tape technology is needed. This technology should enable the graphene structure within the tape to be formed driven by the actual interference spectrum of the target device. Furthermore, it should allow electromagnetic waves to undergo circulating current induction, resistive loss, micro-capacitive coupling, phase hysteresis dissipation, and grounding release along a predetermined graphene path within the tape, while preserving the adhesiveness, flexibility, and die-cutting properties of the pressure-sensitive adhesive. This technology should avoid substituting material stacking for structural innovation and should form a complete closed-loop implementation process, from interference data acquisition and structural coding to roll fabrication and application verification. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a graphene-reinforced EMI shielding tape based on EPDM rubber and its preparation method, thus solving the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an EPDM-based graphene-reinforced EMI shielding tape, comprising an interface impedance modulation layer, a spectrum-coded graphene dissipation layer, an EPDM-based strain decoupling support layer, an EPDM-modified pressure selective grounding layer, and a release protection layer, sequentially stacked from the electromagnetic wave incident side to the attachment side; the spectrum-coded graphene dissipation layer is formed by partitioned laser reduction of a graphene oxide composite precursor film, and includes multiple aperiodic graphene coding units, each of which includes a low-resistivity graphene circulating edge, a semi-reduced graphene dissipation neck, a graphene oxide spacer region, a nano-phase hysteresis dissipation junction, and a ground coupling tail; the low-resistivity graphene circulating edge is connected to the semi-reduced graphene dissipation neck, and the graphene oxide spacer region... The region is adjacent to the low-resistivity graphene circulation edge and separated by nano-gap. The nano-phase hysteresis dissipation junction is disposed at the impedance transition boundary between the low-resistivity graphene circulation edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region. The ground coupling tail extends from the low-resistivity graphene circulation edge or the semi-reduced graphene dissipation neck to the interface between the strain decoupling support layer and the pressure selective grounding layer. The pressure selective grounding layer includes a EPDM-modified EPDM-modified pressure-sensitive adhesive matrix and multiple graphene micro-arches embedded in the EPDM-modified EPDM-modified EPDM-modified pressure-sensitive adhesive matrix. The graphene micro-arches include a bottom connection end, an arc-shaped arched bridge wall, and a top conductive contact. The bottom connection end contacts the ground coupling tail, and the top conductive contact faces the release protection layer.

[0007] Preferably, the thickness of the interface impedance modulation layer is 2 μm to 8 μm, and the interface impedance modulation layer comprises a polar acrylic elastomer, low-reduction graphene microflakes, and sheet-like boron nitride nanofillers. The mass fraction of the low-reduction graphene microflakes in the interface impedance modulation layer is 0.2% to 3.0%, and the mass fraction of the sheet-like boron nitride nanofillers in the interface impedance modulation layer is 0.5% to 6.0%. The in-plane sheet resistance of the interface impedance modulation layer is greater than the in-plane sheet resistance of the low-resistivity graphene circulating edge. The interface impedance modulation layer and the spectrum-encoded graphene dissipative layer are connected through an acrylic segment interpenetrating interface.

[0008] Preferably, the thickness of the spectrally encoded graphene dissipative layer is 6 μm to 30 μm, the sheet resistance of the low-resistivity graphene circulating edge is 5 Ω / sq to 80 Ω / sq, the sheet resistance of the semi-reduced graphene dissipative neck is 100 Ω / sq to 5000 Ω / sq, and the sheet resistance of the graphene oxide spacer region is greater than [missing value]. Ω / sq, the linewidth of the low-resistivity graphene circulating edge is 10μm to 300μm, the width of the nano-gap is 0.8nm to 10nm, the outer diameter of the graphene coding unit is 0.10mm to 3.00mm, and the same spectrum-coded graphene dissipation layer contains at least three sets of graphene coding units with different outer diameters.

[0009] Preferably, the center frequency, equivalent inductance, and equivalent capacitance of the graphene coding unit satisfy the formula , For the first The center frequency corresponding to each graphene coding unit For the first The equivalent inductance of a graphene coding unit, For the first The equivalent capacitance of a graphene coding unit. The number is the sequence number of the graphene coding unit; the equivalent capacitance satisfies the formula , The vacuum permittivity, For the first The relative permittivity of the nanophase hysteresis dissipation junction region of a graphene coding unit. For the first The effective coupling area between the low-resistivity graphene circulating edge and the graphene oxide spacer region in each graphene coding unit. For the first The nanometer gap width of each graphene coding unit.

[0010] Preferably, the nanophase hysteresis dissipation junction includes a polar dielectric layer disposed between the edge of the low-resistivity graphene circulation edge, the edge of the semi-reduced graphene dissipation neck edge, and the edge of the graphene oxide spacer region. The polar dielectric layer is a polydopamine layer with a thickness of 0.5 nm to 20 nm. The polar dielectric layer is located at the impedance gradient boundary formed after the graphene oxide composite precursor film is laser-reduced.

[0011] Preferably, the thickness of the strain decoupling support layer is 5 μm to 25 μm, and the strain decoupling support layer includes an EPDM-grafted acrylic elastomer network, polyurethane elastomer segments, acrylic elastomer segments, and sheet-like silica nanofillers. The EPDM-grafted acrylic elastomer network forms an interpenetrating interface with the back side of the spectrum-coded graphene dissipative layer. The mass fraction of the sheet-like silica nanofillers in the strain decoupling support layer is 0.5% to 8.0%, and the tensile modulus of the strain decoupling support layer is 0.2 MPa to 8 MPa.

[0012] Preferably, the graphene micro-arch bridge has a base diameter of 10 μm to 120 μm, a height of 2 μm to 30 μm, an arch bridge wall thickness of 50 nm to 800 nm, a top conductive contact diameter of 1 μm to 30 μm, and the number of graphene micro-arch bridges per unit square centimeter is 100 to 5000; in the pressure selective grounding layer, a continuous pressure-sensitive adhesive area is provided between adjacent graphene micro-arch bridges, and the continuous pressure-sensitive adhesive area and the top conductive contact are located in the same attachment side surface area.

[0013] Preferably, the preparation method of the EPDM rubber-based graphene-reinforced EMI shielding tape includes: SP1, prepare a graphene oxide composite precursor slurry containing graphene oxide, elastomer emulsion, photothermal conversion aid and rheology modifier, and coat the graphene oxide composite precursor slurry onto a temporary support film to form a graphene oxide composite precursor film. SP2 is used to pre-dry the graphene oxide composite precursor film, so that the graphene oxide composite precursor film is in a semi-cured state. SP3 performs roll-to-roll partitioned laser reduction on the graphene oxide composite precursor film according to the preset graphene coding unit pattern to form low-resistivity graphene circulating edges, semi-reduced graphene dissipation necks and graphene oxide spacer regions. SP4 involves placing the partitioned laser-reduced film in a polydopamine precursor solution environment, allowing the polydopamine precursor to enter the nano-gap between the low-resistivity graphene circulation edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region, and then curing it to form a nano-phase hysteresis dissipation junction. SP5 is formed by coating and curing the back of the spectrum-encoded graphene dissipation layer to form a ternary propylene diene rubber-based strain decoupling support layer. SP6 disperses graphene micro-arch bridges in a EPDM-modified EPDM-modified pressure-sensitive adhesive matrix to form a pressure-selective grounding layer, and makes the bottom connection end of the graphene micro-arch bridge contact the grounding coupling tail end. SP7, a composite release protective layer on the attachment side of the pressure selective grounding layer.

[0014] Preferably, in SP3, the sheet resistance of the laser-reduced graphene region satisfies the formula... , The sheet resistance of the graphene region after laser reduction. The initial sheet resistance of the unreduced graphene oxide composite precursor film. The laser reduction sensitivity coefficient, Let be the laser energy density; the laser energy density satisfies the formula , The average output power of the laser. The number of laser scans in the same area. For laser scanning speed, The effective width of the laser spot; the low-resistivity graphene circulating edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region each use different... .

[0015] Preferably, an interference spectrum data set of the area to be shielded is established before SP3. , For the first The center frequency of each interfering data point For the first The bandwidth of each interfering data point For the first Electromagnetic power density of each interference data point For the first The main electric field polarization direction angle of each interfering data point , and The first The three-dimensional coordinates of each interfering data point in the attachment area coordinate system. For the first The ground proximity parameters corresponding to the locations of each interference data point. The total number of interfering data points; according to the formula Calculate the structural encoding weights. For the first The structural encoding weights of each interfering data point , , and These are the power density weighting factor, bandwidth weighting factor, spatial distance weighting factor, and ground proximity weighting factor, respectively. , For maximum electromagnetic power density, For maximum bandwidth, For the first The normalized distance from each interference data point to the center line of the attached target area is used to generate the outer diameter, linewidth, opening direction, nanometer gap width, dissipation neck sheet resistance, and graphene micro-arch bridge distribution density of the graphene coding unit based on the structural coding weight.

[0016] This invention provides a graphene-reinforced EMI shielding tape based on EPDM rubber and its preparation method. It has the following beneficial effects: 1. This invention forms low-resistivity, semi-reduced, and high-resistivity regions by partitioning the same graphene oxide composite precursor film with laser reduction, so that circulating current induction, resistive dissipation, and microcapacitive coupling are completed in the same continuous film layer, reducing the performance dispersion caused by interface peeling and random dispersion in traditional multi-material stacks.

[0017] 2. This invention uses aperiodic graphene coding units to perform structural matching on the interference spectrum of the area to be shielded, so that the dissipation path inside the tape corresponds to the actual interference frequency, spatial location and grounding conditions, thus shortening the EMI rectification cycle of electronic equipment.

[0018] 3. This invention separates the grounding contact from the pressure-sensitive adhesive wetting area through a pressure-selective grounding layer, enabling the tape to establish a stable discrete grounding path while maintaining adhesion reliability; and buffers bending, thermal cycling and vibration stress through a strain decoupling support layer, so that the graphene coding pattern maintains structural continuity under curved surface adhesion, die-cut edges and long-term service conditions. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the layered structure of the EPDM rubber-based graphene-reinforced EMI shielding tape of the present invention. Figure 2 This is a schematic diagram of the planar structure of the graphene coding unit in the spectrum-coded graphene dissipation layer of the present invention; Figure 3 This is a partially enlarged structural schematic diagram of the nano-phase hysteresis dissipation junction of the present invention; Figure 4 This is a schematic diagram of the structure of the EPDM rubber modified pressure selective grounding layer of the present invention. Figure 5 This is a schematic diagram of the preparation method of the present invention; Figure 6 This is a schematic diagram of the mapping process from interference spectrum data to graphene encoded patterns in this invention. Figure 7 This is a cross-sectional structural diagram of the tape of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1: like Figures 1 to 7 As shown, the EPDM rubber-based graphene-reinforced EMI shielding tape includes an interface impedance modulation layer, a spectrum-coded graphene dissipation layer, an EPDM rubber-based strain decoupling support layer, an EPDM rubber-modified pressure-selective grounding layer, and a release protection layer, sequentially stacked from the electromagnetic wave incident side to the attachment side. The spectrum-coded graphene dissipation layer is formed by roll-to-roll partitioned laser reduction of the same graphene oxide composite precursor film. The film layer simultaneously possesses a low-resistivity graphene circulating edge, a semi-reduced graphene dissipation neck, and an oxide spacer region. Nanoscale phase hysteresis dissipation junctions are set between adjacent impedance regions, allowing high-frequency electromagnetic energy to couple and dissipate between the low-resistivity circulating current, the resistive neck, and the nanoscale gaps. The pressure-selective grounding layer forms a local grounding path through graphene micro-arches, and the continuous area of ​​the pressure-sensitive adhesive retains the attachment wetting interface, thereby combining the electromagnetic dissipation structure, the mechanically flexible structure, and the grounding contact structure into a single tape product.

[0022] The method also includes preparation techniques, such as formulating a graphene oxide composite precursor slurry, coating to form a graphene oxide composite precursor film, semi-curing and pre-drying, roll-to-roll zoned laser reduction, nano-phase hysteresis dissipation junction positioning and curing, strain decoupling support layer composite, pressure selective grounding layer composite, and release protective layer composite. The core control point of this preparation method lies in using laser energy density to determine the sheet resistance of the graphene region, using the graphene coding unit pattern to determine the electromagnetic dissipation path, and using the position of the graphene micro-arch bridges to determine the grounding path after attachment. This transforms the interference spectrum data of the device to be shielded into structural and manufacturing parameters within the tape.

[0023] This application also establishes an encoding model from the interference spectrum to the tape structure. The model uses the interference center frequency, bandwidth, electromagnetic power density, main electric field polarization direction angle, spatial coordinates, and ground proximity parameters collected from the area to be shielded as input to calculate the structural encoding weights. These weights then determine the outer diameter, linewidth, opening direction, nanometer gap width, dissipation neck sheet resistance, and graphene micro-arch bridge distribution density of the graphene encoding units. This model enables the same material system to form different internal graphene patterns and ground contact distributions for different electronic devices, transforming the shielding tape from a general conductive material into a spectrum-customized flexible electromagnetic dissipation device.

[0024] In this embodiment, the layer thickness, particle size, sheet resistance, density, and process temperature are specific implementation parameters of the invention, configured according to the interference spectrum data of the device to be shielded. The electromagnetic wave incident side, as described herein, refers to the side facing the electromagnetic leakage source or electromagnetic incident path after the tape is applied; the application side refers to the side of the tape in contact with the conductive substrate, metal casing, shielding cover, flexible circuit board interface area, or conductive coating of the electronic device.

[0025] This embodiment provides an EMI shielding tape reinforced with graphene and based on EPDM rubber. The tape, from the electromagnetic wave incident side to the attachment side, sequentially comprises an interface impedance modulation layer, a spectrum-coded graphene dissipation layer, an EPDM-based strain decoupling support layer, an EPDM-modified pressure selective grounding layer, and a release protection layer. The interface impedance modulation layer uses a polar acrylic elastomer as the main body, incorporating low-reduction graphene microflakes and sheet-like boron nitride nanofillers. The mass fraction of the low-reduction graphene microflakes in the interface impedance modulation layer is 0.2% to 3.0%, and the mass fraction of the sheet-like boron nitride nanofillers is 0.5% to 6.0%. The thickness of the interface impedance modulation layer is 2 μm to 8 μm. This layer is located on the electromagnetic wave incident side, and its conductivity is lower than that of the spectrum-coded graphene dissipation layer. It is connected to the spectrum-coded graphene dissipation layer through an acrylic segment interpenetrating interface.

[0026] The spectrum-encoded graphene dissipative layer is formed by roll-to-roll partitioned laser reduction of a graphene oxide composite precursor film, with a thickness ranging from 6 μm to 30 μm. The graphene oxide sheets in the graphene oxide composite precursor film have lateral dimensions of 1 μm to 15 μm and sheet thicknesses of 0.8 nm to 5 nm, forming a continuous film layer with an elastomer emulsion. After partitioned laser reduction, low-resistivity graphene circulating edges, semi-reduced graphene dissipative necks, and graphene oxide spacer regions are formed within the film layer. The sheet resistance of the low-resistivity graphene circulating edges is 5 Ω / sq to 80 Ω / sq, the sheet resistance of the semi-reduced graphene dissipative necks is 100 Ω / sq to 5000 Ω / sq, and the sheet resistance of the graphene oxide spacer regions is greater than [missing value]. Ω / sq. The three regions mentioned above originate from the same graphene oxide composite precursor film, and there are no additional multilayer interfaces between the three regions, thus exhibiting high interfacial stability under bending and thermal cycling conditions.

[0027] The graphene coding units in the spectrum-coded graphene dissipation layer are arranged aperiodically. Each graphene coding unit includes a low-resistivity graphene circulating edge, a semi-reduced graphene dissipation neck, an oxide spacer region, a nano-phase hysteresis dissipation junction, and a ground coupling tail. The low-resistivity graphene circulating edge forms an open ring path, a zigzag path, an eccentric spiral path, and a multi-branched path; the semi-reduced graphene dissipation neck is connected in series in the low-resistivity graphene circulating edge; the oxide spacer region is separated from the low-resistivity graphene circulating edge by nano-gap; the nano-phase hysteresis dissipation junction is located at the impedance transition boundary of the low-resistivity graphene circulating edge, the semi-reduced graphene dissipation neck, and the oxide spacer region; the ground coupling tail extends from the graphene coding unit to the pressure-selective grounding layer. The linewidth of the low-resistivity graphene circulating edge is 10μm to 300μm, the nano-gap width is 0.8nm to 10nm, the outer diameter of the graphene coding unit is 0.10mm to 3.00mm, and the same tape area includes at least three sets of graphene coding units with different outer diameters, so that the same tape area simultaneously contains high-frequency small-size coding units, mid-frequency mid-size coding units, and low-frequency long-path foldback coding units.

[0028] The nanoscale phase hysteresis dissipation junction comprises a polar dielectric layer located between the edges of the low-resistivity graphene circulation zone, the dissipation neck of the semi-reduced graphene, and the spacer region of the graphene oxide. The polar dielectric layer is a polydopamine layer with a thickness ranging from 0.5 nm to 20 nm. This layer is introduced into the laser-reduced nano-interstices through wetting, vapor infiltration, or low-concentration solution treatment, and is fixed at the impedance gradient boundaries after curing. Because this layer is located only within the nano-interstices and graphene edges, it does not form a macroscopically continuous insulating barrier layer. Instead, under high-frequency conditions, it collaborates with the graphene coding units to constitute a microcapacitive coupling and phase hysteresis structure.

[0029] A strain-decoupling support layer, with a thickness of 5 μm to 25 μm, is disposed between the spectrum-encoded graphene dissipative layer and the pressure-selective grounding layer. The strain-decoupling support layer comprises an EPDM-grafted acrylic elastomer network, polyurethane elastomer segments, acrylic elastomer segments, and sheet-like silica nanofillers. The mass fraction of the sheet-like silica nanofillers is 0.5% to 8.0%, and the tensile modulus is 0.2 MPa to 8 MPa. The strain-decoupling support layer forms an interpenetrating interface with the back side of the spectrum-encoded graphene dissipative layer. During tape bending, punching, application to curved surfaces, and thermal cycling, the strain-decoupling support layer disperses local stress through elastic segment rearrangement and dynamic hydrogen bond recombination, preventing through-cracks from forming on the low-resistivity graphene circulating edge and the semi-reduced graphene dissipative neck.

[0030] The EPDM-grafted acrylic elastomer network is formed by maleic anhydride-grafted EPDM, hydroxyacrylate monomers, polyurethane prepolymer, and dynamic hydrogen-bonded chain extenders. The mass fraction of maleic anhydride-grafted EPDM in the strain decoupling support layer is 15% to 45%, the mass fraction of polyurethane elastomer segments is 20% to 50%, and the mass fraction of acrylic elastomer segments is 10% to 35%. The EPDM segments form a continuous flexible rubber phase, the polyurethane segments form a polar adhesive phase, and the acrylic segments form an interpenetrating phase compatible with the interfacial impedance modulation layer and the spectrally encoded graphene dissipative layer.

[0031] A pressure-selective grounding layer, with a thickness of 20 μm to 70 μm, is disposed on the attachment side. The pressure-selective grounding layer comprises an EPDM-modified varistor matrix and multiple graphene micro-arches. Each graphene micro-arche includes a bottom connection end, an arc-shaped arch wall, and a top conductive contact. The bottom diameter of the graphene micro-arches ranges from 10 μm to 120 μm, the height from 2 μm to 30 μm, the arch wall thickness from 50 nm to 800 nm, and the diameter of the top conductive contact from 1 μm to 30 μm. The number of graphene micro-arches per square centimeter ranges from 100 to 5000. The bottom connection end contacts the ground coupling tail in the spectrally encoded graphene dissipative layer, and the top conductive contact faces the release liner and is covered by a thin varistor layer. During attachment, the release protective layer is peeled off, and the graphene micro-arches undergo local deformation under the attachment pressure. The top conductive contacts come into contact with the attached conductive substrate, and multiple graphene micro-arches together form a discrete grounding path. Between adjacent graphene micro-arches is a continuous pressure-sensitive adhesive area, which is responsible for attachment wetting and maintaining peel strength.

[0032] The EPDM-modified pressure-sensitive adhesive matrix comprises EPDM rubber, maleic anhydride-grafted EPDM rubber, hydrogenated petroleum resin, liquid polyisobutylene, acrylate pressure-sensitive adhesive resin, and an antioxidant. The total mass fraction of EPDM rubber and maleic anhydride-grafted EPDM rubber is 20% to 50%, the mass fraction of hydrogenated petroleum resin is 10% to 35%, the mass fraction of liquid polyisobutylene is 5% to 25%, and the mass fraction of acrylate pressure-sensitive adhesive resin is 15% to 45%. Graphene micro-arches are embedded within this EPDM-modified pressure-sensitive adhesive matrix, with the bottom connection end in contact with the grounding coupling tail end, and the top conductive contact facing the attachment side.

[0033] In this embodiment, the interference spectrum data set of the area to be shielded is established according to the following formula: ; In the formula This represents the set of interference spectrum data for the area to be shielded. Indicates the first The sequence number of each interfering data point; Indicates the total number of interfering data points; Indicates the first The center frequency of each interfering data point, in Hz; Indicates the first The bandwidth of each interference data point is expressed in Hz. Indicates the first Electromagnetic power density of each interference data point, in W / m²; Indicates the first The polarization direction angle of the main electric field of each interference data point is expressed in rad. Indicates the first The horizontal coordinates of each interference data point in the coordinate system of the attached area, in meters; Indicates the first The vertical coordinates of each interference data point in the coordinate system of the attached area, in meters; Indicates the first The height coordinates of each interference data point in the coordinate system of the attached area, in meters; Indicates the first Ground proximity parameters corresponding to the location of each interference data point; This indicates the index conditions that elements in the set must satisfy. The interference spectrum data is acquired by a near-field scanning probe, spectrum analyzer, vector network analyzer, anechoic chamber radiation testing system, and monitoring points inside the equipment, and is registered with the coordinate system of the attached area.

[0034] After obtaining the interference spectrum dataset, the structure coding weights are calculated: ; In the formula Indicates the first The structural encoding weights of each interfering data point; This represents the power density weighting coefficient; This represents the bandwidth weighting coefficient; Indicates the spatial distance weighting coefficient; Indicates the ground proximity weighting coefficient; Indicates the first Electromagnetic power density of each interference data point, in W / m²; This represents the maximum electromagnetic power density in the interference spectrum data set, expressed in W / m². Indicates the first The bandwidth of each interference data point is expressed in Hz. This represents the maximum bandwidth in the interference spectrum data set, expressed in Hz. Indicates the first Normalized distance from each interfering data point to the center line of the attached target area; Indicates the first The ground proximity parameters corresponding to the locations of the interference data points. , , and All are non-negative numbers and satisfy the following conditions: This formula transforms power density, bandwidth, spatial location, and ground proximity into structural coding weights. The larger the structural coding weight, the higher the density of graphene coding units and graphene micro-arch bridges in the corresponding region.

[0035] The center frequency, equivalent inductance, and equivalent capacitance of the graphene encoding unit satisfy the following relationship: ; In the formula Indicates the first The center frequency corresponding to each graphene coding unit is expressed in Hz. Represents pi; Indicates the first The equivalent inductance of a graphene coding unit, in ohms (H); Indicates the first The equivalent capacitance of a graphene coding unit, expressed in volts (F). This formula is used to determine the circulation path length, opening size, and nano-gap structure of the graphene coding unit based on the target interference frequency.

[0036] The equivalent capacitance of the graphene coding unit satisfies: ; In the formula Indicates the first The equivalent capacitance of a graphene coding unit, in F; This represents the vacuum permittivity, with units of F / m; Indicates the first The relative permittivity of the nanophase hysteresis dissipation junction region in each graphene coding unit; Indicates the first The effective coupling area between the low-resistivity graphene circulating edge and the graphene oxide spacer region in each graphene coding unit is expressed in m². Indicates the first The effective width of the nanometer gaps in each graphene coding unit is measured in meters (m). This is achieved by adjusting... and Within the same film thickness range, graphene coding units targeting different interference frequencies are formed.

[0037] The power loss of the graphene coding unit at the target frequency is calculated using the following formula: ; In the formula Indicates the first The power loss of each graphene coding unit at the target frequency, in W; Indicates the first The effective value of the induced current in the low-resistivity graphene circulating edge of each graphene coding unit, in A; Indicates the first The resistance of the semi-reduced graphene dissipation neck in each graphene coding unit, in Ω; Indicates the first The angular frequency of each interference data point, in rad / s, and ; Indicates the first The equivalent capacitance of a graphene coding unit, in F; Indicates the first The effective value of the high-frequency voltage across the nano-gap of each graphene coding unit, in V; Indicates the first The dielectric loss tangent of the nanophase hysteresis dissipation junction in a graphene coding unit. In this formula, Characterizing the resistive loss in the dissipation neck of semi-reduced graphene. Characterize the dielectric relaxation loss in nanophase hysteresis dissipation junctions.

[0038] In the plane coordinates of the tape At this location, the density of graphene coding units is determined according to the following formula: ; In the formula Represents the plane coordinates of the tape The density of graphene coding units at the location, in units / m²; This indicates the minimum graphene coding unit density, expressed in units per m². This indicates the highest density of graphene coding units, expressed in units per m². Represents the plane coordinates of the tape The structural coding weights are obtained by interpolating adjacent interfering data points. This represents the maximum structural coding weight within the attachment region. This formula causes the graphene coding units to be arranged in a gradient spatially according to interference intensity and ground proximity conditions.

[0039] The density of graphene micro-arches in the pressure-selective grounding layer is determined according to the following formula: ; In the formula Represents the plane coordinates of the tape The density of graphene microarches at the location, in units of units / m²; This indicates the minimum density of graphene microarches, expressed in units of cells / m². This indicates the highest density of graphene microarches, expressed in units of one arch per m². Represents the plane coordinates of the tape Ground proximity parameters at the location; Represents the plane coordinates of the tape The amount of residual induced charge at the location, expressed in C; This represents the maximum residual induced charge within the attachment area, expressed in carbon (C). This formula allows for the concentrated placement of graphene micro-arches in locations with high residual charge release requirements and sufficient grounding conditions.

[0040] The sheet resistance of the laser-reduced graphene region is determined according to the following calibration formula: ; In the formula The sheet resistance of the graphene region after laser reduction is expressed in Ω / sq. The initial sheet resistance of the unreduced graphene oxide composite precursor film is expressed in Ω / sq. Indicates the laser reduction sensitivity coefficient; This represents laser energy density, with units of J / m². This represents an exponential function with the natural constant as its base. The formula is obtained through pre-production sample calibration and is used to convert the target sheet resistance into laser manufacturing parameters.

[0041] The laser energy density and laser process parameters satisfy the following: ; In the formula This represents laser energy density, with units of J / m². This represents the average laser output power, measured in W. Indicates the number of laser scans conducted in the same area; This indicates the laser scanning speed, expressed in m / s. This indicates the effective width of the laser spot, measured in meters (m). By changing... , , and Different sheet resistance regions are formed within the same graphene oxide composite precursor film.

[0042] The preparation process of this embodiment is as follows. SP1: Prepare a graphene oxide composite precursor slurry by dispersing graphene oxide with a lateral size of 1 μm to 15 μm and a sheet thickness of 0.8 nm to 5 nm in a mixed solvent of water and alcohol. Add EPDM-grafted acrylic elastomer emulsion, polyurethane elastomer emulsion, photothermal conversion aid, and rheology modifier. After high-shear dispersion, filtration, and vacuum degassing, obtain a graphene oxide composite precursor slurry with a solid content of 6% to 22%. SP2: Coat the graphene oxide composite precursor slurry onto a temporary support film using a slot coating method. Pre-dry at 45°C to 85°C to bring the film to a semi-cured state. The semi-cured film has a continuous morphology and retains space for elastomer chain rearrangement. SP3: Based on the graphene coding unit pattern, the semi-cured film layer is subjected to roll-to-roll partitioned laser reduction. A higher laser energy density is used in the low-resistivity graphene circulation edge region, a medium laser energy density is used in the semi-reduced graphene dissipation neck region, and the graphene oxide interstitial region is left unreduced or treated with a low laser energy density. SP4: The laser-reduced film layer is placed in a polydopamine precursor solution, allowing the polydopamine precursor to enter the nano-interstic gaps at the graphene edge. It is then cured at 80℃ to 160℃ to form nano-phase hysteresis dissipation junctions. SP5: A EPDM-grafted acrylic elastomer precursor solution is coated onto the back of the spectrally encoded graphene dissipation layer and cured to form a strain decoupling support layer. SP6: Graphene micro-arches are mixed with an EPDM-modified pressure-sensitive adhesive matrix to form a pressure-selective grounding layer slurry. This slurry is then applied using a microgravure coating or microimprinting to form a pressure-selective grounding layer, ensuring that the bottom connection end of the graphene micro-arches is in contact with the grounding coupling tail end. SP7 is an EMI shielding tape made of EPDM rubber and graphene reinforced by attaching a composite release protective layer to the pressure selective grounding layer and then slitting, die-cutting and finished product inspection. Specific Implementation Example 2: In this embodiment, the tape is used in the edge area of ​​the RF shielding cover of the 5G communication terminal. The total thickness of the tape is 78 μm, including a 4 μm thickness for the interface impedance modulation layer, a 16 μm thickness for the spectrum-coded graphene dissipation layer, a 10 μm thickness for the strain decoupling support layer, and a 48 μm thickness for the pressure-selective grounding layer. The sheet resistance of the low-resistivity graphene circulating edge is 20 Ω / sq to 45 Ω / sq, the sheet resistance of the semi-reduced graphene dissipation neck is 300 Ω / sq to 900 Ω / sq, and the sheet resistance of the graphene oxide spacer region is greater than [missing value]. Ω / sq. The outer diameter of the graphene coding unit is divided into three groups: 0.18mm to 0.45mm, 0.50mm to 1.20mm, and 1.50mm to 2.20mm. The micro-gap width is 1nm to 6nm, the bottom diameter of the graphene micro-arches is 25μm to 60μm, the height is 6μm to 15μm, and the number of graphene micro-arches per square centimeter is 1200 to 2600. This structure is attached between the edge of the RF shield and the motherboard grounding area, forming a continuous structural connection between the low-resistivity graphene circulating edge, the semi-reduced graphene dissipation neck, and the graphene micro-arches. Specific Implementation Example 3: In this embodiment, the tape is used in the seam area of ​​the battery management system housing for new energy vehicles. The total thickness of the tape is 118 μm, including a 6 μm thickness for the interface impedance modulation layer, a 28 μm thickness for the spectrally encoded graphene dissipative layer, an 18 μm thickness for the strain decoupling support layer, and a 66 μm thickness for the pressure selective grounding layer. The graphene encoding unit adopts a long-path foldback structure with an outer diameter of 0.50 mm to 3.00 mm, a sheet resistance of 500 Ω / sq to 3000 Ω / sq for the semi-reduced graphene dissipative neck, a bottom diameter of 60 μm to 110 μm for the graphene micro-arch bridge, a height of 12 μm to 28 μm, and a tensile modulus of 0.5 MPa to 2.5 MPa for the strain decoupling support layer. This structure is suitable for attachment to rough metal housings and compensates for micro-undulations on the housing surface through the relatively high height of the graphene micro-arch bridge. Specific Implementation Example 4: In this embodiment, adhesive tape is used in the seam area of ​​the high-speed optical module housing. The total thickness of the tape is 55 μm, including a 12 μm thick spectral-encoded graphene dissipative layer, an 8 μm thick strain decoupling support layer, and a 32 μm thick pressure-selective grounding layer. The outer diameter of the graphene encoding unit is 0.10 mm to 0.60 mm, the linewidth of the low-resistivity graphene circulating edge is 10 μm to 80 μm, the nano-gap width is 0.8 nm to 5 nm, and the height of the graphene micro-arch bridge is 2 μm to 10 μm. When this structure is arranged at the housing seam, it occupies a small thickness and addresses the high-speed signal harmonics and gap leakage frequencies through small-sized, high-density graphene encoding units.

[0046] The testing items of this invention include shielding effectiveness in the target frequency band, absorption dominance coefficient, grounding resistance after attachment, 180° peel strength, sheet resistance change rate after bending, grounding resistance change rate after damp heat aging, and shielding effectiveness retention rate after thermal cycling. Preferably, the total thickness of the tape is controlled between 55μm and 125μm, the total shielding effectiveness in the target frequency band is 45dB to 75dB, the absorption dominance coefficient is not less than 0.60, the grounding resistance after attachment is 0.08Ω to 0.50Ω, the 180° peel strength is not less than 8N / 25mm, the sheet resistance change rate after 1000 bends with a radius of 5mm is not higher than 15%, the grounding resistance change rate after aging at 85℃ and 85% relative humidity for 500h is not higher than 25%, and the shielding effectiveness retention rate after 300 thermal cycles from -40℃ to 125℃ is not less than 90%. The above-mentioned test items directly correspond to the spectrum-encoded graphene dissipation layer, nano-phase hysteresis dissipation junction, strain decoupling support layer, and pressure selective grounding layer, which can verify the structural stability and electromagnetic compatibility of the tape in actual electronic devices.

[0047] In the EPDM-based embodiment, the strain decoupling support layer is formulated with 28 parts maleic anhydride-grafted EPDM rubber, 42 parts polyurethane elastomer emulsion, 22 parts acrylic elastomer emulsion, and 8 parts flake silica nanofiller; the pressure selective grounding layer is formulated with 24 parts EPDM rubber, 12 parts maleic anhydride-grafted EPDM rubber, 18 parts hydrogenated petroleum resin, 12 parts liquid polyisobutylene, 29 parts acrylic pressure-sensitive adhesive resin, 1 part antioxidant, and 4 parts graphene micro-arch bridges. In this embodiment, the tape product is still used for EMI shielding and grounding attachment; the EPDM rubber is used to define the rubber elastic phase and pressure-sensitive adhesive phase of the tape, and the product application is not changed to waterproof rolls, roofing sheets, or waterproof blankets.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A graphene-reinforced EMI shielding tape based on EPDM rubber, characterized in that, The system comprises, in sequence from the electromagnetic wave incident side to the attachment side, an interface impedance modulation layer, a spectrum-coded graphene dissipation layer, an EPDM-based strain decoupling support layer, an EPDM-modified pressure-selective grounding layer, and a release protection layer. The spectrum-coded graphene dissipation layer is formed by partitioned laser reduction of a graphene oxide composite precursor film. The spectrum-coded graphene dissipation layer includes multiple aperiodicly arranged graphene coding units. Each graphene coding unit includes a low-resistivity graphene circulating edge, a semi-reduced graphene dissipation neck, an EPDM spacer region, a nanoscale phase hysteresis dissipation junction, and a grounding coupling tail. The low-resistivity graphene circulating edge is connected to the semi-reduced graphene dissipation neck, and the EPDM spacer region is adjacent to the low-resistivity graphene circulating edge and separated by nanoscale gaps. The nano-phase hysteresis dissipation junction is disposed at the impedance transition boundary between the low-resistivity graphene circulation edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region. The ground coupling tail extends from the low-resistivity graphene circulation edge or the semi-reduced graphene dissipation neck to the interface between the strain decoupling support layer and the pressure selective grounding layer. The pressure selective grounding layer includes a EPDM-modified EPDM-modified pressure-sensitive adhesive matrix and multiple graphene micro-arches embedded in the EPDM-modified EPDM-modified EPDM-modified pressure-sensitive adhesive matrix. Each graphene micro-arch includes a bottom connection end, an arc-shaped arch wall, and a top conductive contact. The bottom connection end contacts the ground coupling tail, and the top conductive contact faces the release protection layer.

2. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The thickness of the interface impedance modulation layer is 2 μm to 8 μm. The interface impedance modulation layer includes a polar acrylic elastomer, low-reduction graphene microflakes, and sheet-like boron nitride nanofillers. The mass fraction of the low-reduction graphene microflakes in the interface impedance modulation layer is 0.2% to 3.0%, and the mass fraction of the sheet-like boron nitride nanofillers in the interface impedance modulation layer is 0.5% to 6.0%. The in-plane sheet resistance of the interface impedance modulation layer is greater than the in-plane sheet resistance of the low-resistivity graphene circulating edge. The interface impedance modulation layer and the spectrum-encoded graphene dissipative layer are connected by an acrylic segment interpenetrating interface.

3. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The thickness of the spectrally encoded graphene dissipative layer is 6 μm to 30 μm, the sheet resistance of the low-resistivity graphene circulation edge is 5 Ω / sq to 80 Ω / sq, the sheet resistance of the semi-reduced graphene dissipative neck is 100 Ω / sq to 5000 Ω / sq, and the sheet resistance of the graphene oxide spacer region is greater than [missing value]. Ω / sq, the linewidth of the low-resistivity graphene circulating edge is 10μm to 300μm, the width of the nano-gap is 0.8nm to 10nm, the outer diameter of the graphene coding unit is 0.10mm to 3.00mm, and the same spectrum-coded graphene dissipation layer contains at least three sets of graphene coding units with different outer diameters.

4. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The center frequency, equivalent inductance, and equivalent capacitance of the graphene encoding unit satisfy the formula. , For the first The center frequency corresponding to each graphene coding unit For the first The equivalent inductance of a graphene coding unit, For the first The equivalent capacitance of a graphene coding unit. The number is the sequence number of the graphene coding unit; the equivalent capacitance satisfies the formula , The vacuum permittivity, For the first The relative permittivity of the nanophase hysteresis dissipation junction region of a graphene coding unit. For the first The effective coupling area between the low-resistivity graphene circulating edge and the graphene oxide spacer region in each graphene coding unit. For the first The nanometer gap width of each graphene coding unit.

5. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The nanophase hysteresis dissipation junction includes a polar dielectric layer disposed between the edge of the low-resistivity graphene circulation edge, the edge of the semi-reduced graphene dissipation neck edge, and the edge of the graphene oxide spacer region. The polar dielectric layer is a polydopamine layer with a thickness of 0.5 nm to 20 nm. The polar dielectric layer is located at the impedance gradient boundary formed after the graphene oxide composite precursor film is laser-reduced.

6. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The strain decoupling support layer has a thickness of 5 μm to 25 μm and includes an EPDM-grafted acrylic elastomer network, polyurethane elastomer segments, acrylic elastomer segments, and sheet-like silica nanofillers. The EPDM-grafted acrylic elastomer network forms an interpenetrating interface with the back side of the spectrum-coded graphene dissipative layer. The sheet-like silica nanofillers have a mass fraction of 0.5% to 8.0% in the strain decoupling support layer, and the tensile modulus of the strain decoupling support layer is 0.2 MPa to 8 MPa.

7. The EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 1, characterized in that, The graphene micro-arches have a base diameter of 10 μm to 120 μm, a height of 2 μm to 30 μm, an arch wall thickness of 50 nm to 800 nm, and a top conductive contact diameter of 1 μm to 30 μm. The number of graphene micro-arches per square centimeter is 100 to 5000. In the pressure selective grounding layer, a continuous pressure-sensitive adhesive area is provided between adjacent graphene micro-arches, and the continuous pressure-sensitive adhesive area and the top conductive contact are located in the same attachment side surface area.

8. A method for preparing the EPDM rubber-based graphene-reinforced EMI shielding tape according to any one of claims 1 to 7, characterized in that, include: SP1, prepare a graphene oxide composite precursor slurry containing graphene oxide, elastomer emulsion, photothermal conversion aid and rheology modifier, and coat the graphene oxide composite precursor slurry onto a temporary support film to form a graphene oxide composite precursor film. SP2 is used to pre-dry the graphene oxide composite precursor film, so that the graphene oxide composite precursor film is in a semi-cured state. SP3 performs roll-to-roll partitioned laser reduction on the graphene oxide composite precursor film according to the preset graphene coding unit pattern to form low-resistivity graphene circulating edges, semi-reduced graphene dissipation necks and graphene oxide spacer regions. SP4 involves placing the partitioned laser-reduced film in a polydopamine precursor solution environment, allowing the polydopamine precursor to enter the nano-gap between the low-resistivity graphene circulation edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region, and then curing it to form a nano-phase hysteresis dissipation junction. SP5 is formed by coating and curing the back of the spectrum-encoded graphene dissipation layer to form a ternary propylene diene rubber-based strain decoupling support layer. SP6, graphene micro-arch bridges are dispersed in a EPDM-modified pressure-sensitive adhesive matrix to form a pressure-selective grounding layer, and the bottom connection end of the graphene micro-arch bridge is in contact with the grounding coupling tail end. SP7, a composite release protective layer on the attachment side of the pressure selective grounding layer.

9. The method for preparing the EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 8, characterized in that, In SP3, the sheet resistance of the laser-reduced graphene region satisfies the formula... , The sheet resistance of the graphene region after laser reduction. The initial sheet resistance of the unreduced graphene oxide composite precursor film. The laser reduction sensitivity coefficient, Let be the laser energy density; the laser energy density satisfies the formula , The average output power of the laser. The number of laser scans in the same area. For laser scanning speed, The effective width of the laser spot; the low-resistivity graphene circulating edge, the semi-reduced graphene dissipation neck, and the graphene oxide spacer region each use different... .

10. The method for preparing the EPDM rubber-based graphene-reinforced EMI shielding tape according to claim 8, characterized in that, Before SP3, establish the interference spectrum data set of the area to be shielded. , For the first The center frequency of each interfering data point For the first The bandwidth of each interfering data point For the first Electromagnetic power density of each interference data point For the first The main electric field polarization direction angle of each interfering data point , and The first The three-dimensional coordinates of each interfering data point in the attachment area coordinate system. For the first The ground proximity parameters corresponding to the locations of each interference data point. The total number of interfering data points; according to the formula Calculate the structural encoding weights. For the first The structural encoding weights of each interfering data point , , and These are the power density weighting coefficient, bandwidth weighting coefficient, spatial distance weighting coefficient, and ground proximity weighting coefficient, respectively. , For maximum electromagnetic power density, For maximum bandwidth, For the first The normalized distance from each interference data point to the center line of the attached target area is used to generate the outer diameter, linewidth, opening direction, nanometer gap width, dissipation neck sheet resistance, and graphene micro-arch bridge distribution density of the graphene coding unit based on the structural coding weight.

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