Anti-curling and anti-counterfeiting tape and its manufacturing method

Abstract

This invention provides an anti-lifting and anti-counterfeiting tape and its manufacturing method. From top to bottom, it comprises a substrate layer, an anti-counterfeiting pattern layer, and a pressure-sensitive adhesive layer with a functional gradient structure. The pressure-sensitive adhesive layer is an integrally molded single-layer structure, and in the thickness direction perpendicular to the plane of the substrate layer, the cohesive strength of the pressure-sensitive adhesive layer exhibits an asymmetric gradient distribution. The pressure-sensitive adhesive layer includes a high-cohesion region: near the anti-counterfeiting pattern layer, the chemical cross-linking density of which keeps the elastic modulus of this region within a preset range, thereby suppressing elastic stringing deformation of the adhesive under peeling force. This invention achieves effective interception and dissipation of the substrate's rebound stress by setting a low-modulus "high-wetting region" on the adhesive side and introducing an "internal stress self-adaptive layer" under the substrate. While ensuring long-lasting adhesion without lifting on curved surfaces, it avoids damage to the cardboard fibers caused by strong peeling, achieving a balance of "strong adhesion without fiber breakage."

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-counterfeit adhesive tape, in particular to an anti-warping anti-counterfeit adhesive tape and a manufacturing method thereof. BACKGROUND

[0002] As an important security packaging material, the void anti-counterfeit adhesive tape is widely used in the fields of electronic products, logistics seals, high-value commodity anti-drop, etc. Its basic structure usually includes: a substrate layer (such as a polyester film PET), an anti-counterfeit information layer (release ink graphics) printed on the surface of the substrate, and a pressure-sensitive adhesive layer covering the anti-counterfeit information layer. The prior art usually adopts the method of increasing the thickness of the adhesive layer or improving the initial adhesion, but this leads to serious "interface contradiction": On the one hand, the increased adhesion to resist warping causes the adhesive to deeply wet the surface of the adherend, resulting in excessive peeling force when the tape is peeled off, which easily causes the surface fibers of the carton to tear (break fibers) and cover the anti-counterfeit information; On the other hand, the traditional uniform adhesive layer is prone to filament-shaped deformation when subjected to stress peeling, and the peeling stress cannot be precisely focused on the interface between the anti-counterfeit graphics layer and the adhesive layer, resulting in chaotic interface fracture logic, blurred or even invalid anti-counterfeit graphics edges; Therefore, an anti-warping anti-counterfeit adhesive tape and a manufacturing method thereof are provided. SUMMARY

[0003] Therefore, the present application provides an anti-warping anti-counterfeit adhesive tape and a manufacturing method thereof to solve or alleviate the technical problems in the prior art, and at least provides a beneficial choice.

[0004] The technical solution of the present application is as follows: an anti-warping anti-counterfeit adhesive tape, which comprises, from top to bottom, a substrate layer, an anti-counterfeit pattern layer, and a pressure-sensitive adhesive layer with a functional gradient structure; The pressure-sensitive adhesive layer is a single-layer structure formed in one piece, and the cohesive strength of the pressure-sensitive adhesive layer is asymmetrically distributed in the thickness direction perpendicular to the plane of the substrate layer; The pressure-sensitive adhesive layer comprises: 1. A high-cohesion zone: close to the side of the anti-counterfeit pattern layer. This area has a high chemical crosslinking density and a high elastic modulus. When the adhesive tape is subjected to a peeling force, this high modulus area can effectively resist the viscoelastic tensile deformation of the adhesive, thereby forcing the peeling fracture surface to be precisely locked on the physical bonding surface between the anti-counterfeit pattern layer and the pressure-sensitive adhesive layer.

[0005] 2. High Wetting Area: The side furthest from the anti-counterfeiting pattern layer and used to contact the substrate (e.g., corrugated cardboard box). This area has a significantly lower chemical cross-linking density than the aforementioned high-cohesion area, allowing its macromolecular chain segments to maintain high mobility and surface free energy. During bonding, this area can wet the microscopically rough surface of the substrate through the deformation depth of the molecular chains; after bonding, the low-modulus colloid can act as a stress dissipation layer, absorbing and buffering the elastic recovery stress of the substrate layer caused by bending or changes in ambient temperature and humidity.

[0006] As a preferred embodiment of the present invention, the pressure-sensitive adhesive layer has a continuously distributed crosslinking density transition section between the high cohesion region and the high wetting region. This transition section allows the physical properties inside the adhesive layer to evolve smoothly, avoiding the defects of "interlayer stress concentration" and "interlayer self-peeling" that are prone to occur in traditional double-layer adhesive composite processes.

[0007] As a preferred technical solution of the present invention: To further eliminate the lifting force from the mechanical source, an internal stress self-adaptive layer is also provided between the substrate layer and the anti-counterfeiting pattern layer. This layer is composed of a modified thermoplastic polyurethane (TPU) coating with a Young's modulus between that of the substrate layer and the pressure-sensitive adhesive layer (high cohesion region), and has a thickness of 5μm to 15μm. This layer acts as an elastic damper, capable of intercepting and dissipating more than 60% of the rebound stress generated by the rigid substrate (such as PET), preventing it from being directly transmitted downwards to the pressure-sensitive adhesive interface.

[0008] As a preferred embodiment of the present invention, the gel fraction of the pressure-sensitive adhesive layer is G1 on the side of the high cohesion region and G2 on the side of the high wetting region. Through the synergistic control of the formulation and curing process, the difference between G1 and G2 is greater than or equal to 30%, and the value range of G1 is 75% to 95%, while the value range of G2 is 30% to 55%.

[0009] As another objective of the present invention, a method for manufacturing the above-mentioned anti-peeling and anti-counterfeiting tape is provided: a single layer of pressure-sensitive adhesive containing a photoinitiator is coated on the surface of a substrate with an anti-counterfeiting pattern layer; then gradient curing is performed: a single-sided irradiation is performed from one side of the substrate layer using an ultraviolet light source of a specific wavelength; The process involves the following: when the photoinitiator in the pressure-sensitive adhesive absorbs ultraviolet light, the light energy decreases exponentially with the penetration depth. The adhesive near the light source (i.e., near the substrate and the anti-counterfeiting pattern layer) absorbs high-energy radiation, rapidly generating a large number of free radicals to form a high-density cross-linked network (forming a high-cohesion region); while the adhesive far from the light source (i.e., the exposed contact surface) only receives the attenuated weak light energy, and the cross-linking reaction is limited (forming a high-wetting region). Thus, with a simplified process of one coating and one light exposure, a gradient adhesive layer with asymmetrical physical properties is constructed in situ.

[0010] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: I. This invention constructs a high-cohesion region with high cross-linking density and high elasticity on the side of the pressure-sensitive adhesive layer near the anti-counterfeiting pattern layer. When the tape is peeled off under force, the high modulus of this region effectively suppresses the viscoelastic tensile deformation of the adhesive, forcibly focusing and locking the peeling stress precisely on the physical bonding surface between the anti-counterfeiting layer and the adhesive layer. This achieves the technical effect of peeling off the anti-counterfeiting pattern as crisply as an eggshell, with sharp edges, 100% clear color display, and no adhesive residue.

[0011] Second, by setting a low-modulus "high wetting zone" on the bonding side and introducing an "internal stress self-adaptive layer" under the substrate, the present invention achieves effective interception and dissipation of the rebound stress of the substrate; while ensuring that the curved surface is bonded for a long time without lifting, it avoids the damage to the cardboard fiber caused by strong peeling, thus achieving a balance of "strong adhesion and no fiber breakage".

[0012] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application 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 of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Fig. 1 This is a cross-sectional structural diagram of the tape product of the present invention; Fig. 2 This is a flowchart of the manufacturing process of the present invention. Detailed Implementation

[0015] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0016] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] like Figs. 1-2As shown, this embodiment of the invention provides an anti-warping and anti-counterfeiting tape, characterized in that it comprises, from top to bottom, a substrate layer, an anti-counterfeiting pattern layer, and a pressure-sensitive adhesive layer with a functional gradient structure; The pressure-sensitive adhesive layer is an integrally molded single-layer structure, and in the thickness direction perpendicular to the plane of the substrate layer, the cohesive strength of the pressure-sensitive adhesive layer exhibits an asymmetric gradient distribution. The pressure-sensitive adhesive layer includes: High cohesion area: The chemical cross-linking density of the area near the anti-counterfeiting pattern layer keeps the elastic modulus of the area within a preset range, so as to suppress the elastic stringing deformation of the colloid under the action of peeling force, so as to force the peeling interface to lock at the bonding surface between the anti-counterfeiting pattern layer and the pressure-sensitive adhesive layer. High wetting area: The side away from the anti-counterfeiting pattern layer and used to contact the object being applied. Its chemical cross-linking density is lower than that of the high cohesion area. It is used to wet the surface of the object being applied through the deformation of the molecular chains and to absorb the elastic recovery stress generated by the substrate layer.

[0018] The pressure-sensitive adhesive layer has a continuously distributed crosslinking density transition section between the high cohesive region and the high wetting region.

[0019] An internal stress self-adaptive layer is provided between the substrate layer and the anti-counterfeiting pattern layer; the internal stress self-adaptive layer is composed of an elastomer coating, whose Young's modulus is less than that of the substrate layer but greater than that of the high cohesive region of the pressure-sensitive adhesive layer.

[0020] The pressure-sensitive adhesive layer has a gel fraction of G1 on the side of the high cohesion region and a gel fraction of G2 on the side of the high wetting region, satisfying the following conditions: the difference between G1 and G2 is greater than or equal to 30%; and the value of G1 is in the range of 75% to 95%.

[0021] The internal stress self-adaptive layer is a modified thermoplastic polyurethane (TPU) coating with a thickness of 5μm-15μm.

[0022] The substrate layer is a biaxially stretched polyester film or a biaxially stretched polypropylene film with a thickness of 15μm-35μm.

[0023] The anti-counterfeiting pattern layer is formed by partial printing of UV-curable release ink. After curing, the release ink forms a pre-set difference in peel force with the high cohesion area of ​​the pressure-sensitive adhesive layer.

[0024] Raw material and testing standards description: Pressure-sensitive adhesive base liquid: a hydroxyl acrylic resin solution prepared by copolymerization of isooctyl acrylate (2-EHA), butyl acrylate (BA) and acrylic acid (AA), with a solid content of 45% and a viscosity of 2500-3000 mPa·s.

[0025] Crosslinking agent: Isocyanate curing agent (such as Bayer Desmodur L75).

[0026] Photoinitiator: TPO (2,4,6-trimethylbenzoyl diphenylphosphine oxide) was selected, which has extremely high absorption efficiency for ultraviolet light in the 365nm-395nm wavelength range.

[0027] Buffer layer resin: Modified aliphatic thermoplastic polyurethane (TPU) solution, with its Young's modulus adjusted to 5.5 × 10⁻⁶ after film formation. 6 Pa.

[0028] Gel fraction (degree of crosslinking) test method: Soxhlet extraction with toluene solvent was used. After extraction for 24 hours, the gel was dried and weighed to calculate the mass fraction of insoluble matter. For gradient adhesive layers, a precision slicer was used to divide the dry adhesive layer into upper and lower layers along the thickness direction for testing to obtain approximate values ​​of G1 (anti-counterfeiting side) and G2 (adhesive side).

[0029] Example 1 S1. Coating with an internal stress self-adaptive layer: A 25μm thick biaxially oriented polyester (PET) film is corona treated (surface tension reaches 42 dyne / cm). A TPU solution is uniformly coated on its lower surface using a micro-gravure coater. After drying in a three-stage oven at 80℃, 90℃, and 100℃, a buffer layer with a dry film thickness of 10μm is formed.

[0030] S2. Printing Anti-counterfeiting Pattern Layer: UV release ink (with the pattern set to "VOID") is partially printed on the surface of the above-mentioned buffer layer using an anilox roller, and then passed through a medium-pressure mercury lamp (energy of 300mJ / cm). 2 Completely solidify.

[0031] S3. Preparation of gradient pressure-sensitive adhesive solution: Take 100 parts by weight of pressure-sensitive adhesive main liquid, add 0.5 parts of crosslinking agent and 2.0 parts of photoinitiator TPO, stir at high speed at 500r / min for 20 minutes, and then degas under vacuum.

[0032] S4. Coating and Gradient Curing: Using a comma-shaped doctor blade, apply the adhesive to the substrate with the anti-counterfeiting layer, setting the dry film thickness to 25μm. Place the roll into an oven (70℃-90℃) to evaporate the solvent. Then, proceed to the UV curing section, using a 365nm UV-LED surface light source, irradiating only one side of the PET substrate from top to bottom, with the irradiation energy controlled at 350mJ / cm². 2 After being wound up and cured for 48 hours, finished tape A is obtained.

[0033] Measurement data: The gel fraction in the high cohesive zone G1 was 86%, the gel fraction in the high wetting zone G2 was 43%, and the gradient difference G was 43%.

[0034] Example 2 The process is basically the same as in Example 1, except that: the substrate is replaced with a 30μm BOPP film; the dry film thickness of the TPU buffer layer is reduced to 5μm; the amount of photoinitiator TPO added in the pressure-sensitive adhesive formulation is reduced to 1.0 part; and the UV single-sided irradiation energy is reduced to 200mJ / cm². 2 ; Finished tape B was obtained through testing. Measurement data: G1 was 76%, G2 was 41%, and the difference in crosslinking degree between the two was 35%.

[0035] Example 3 The process is basically the same as in Example 1, except that: the substrate is replaced with a 15μm high-transparency PET film; the dry film thickness of the TPU buffer layer is increased to 15μm; the amount of photoinitiator TPO added is increased to 3.5 parts; and the UV single-sided irradiation energy is increased to 500mJ / cm². 2 .

[0036] The finished adhesive tape C was obtained through testing. Measurement data: G1 was 94%, G2 was 52%, and the difference in crosslinking degree between the two was 42%.

[0037] Comparative Example 1 The preliminary preparation steps S1 to S3 are exactly the same as in Example 1. In the curing step S4, no photoinitiator is added, but the amount of crosslinking agent is increased to 1.5 parts, and a pure thermosetting process (baking at 110°C for 5 minutes) is used to form a uniform chemical crosslinking network inside the adhesive layer.

[0038] Comparative tape D was prepared. Measurement data: The overall gel fraction of the adhesive layer remained consistent at 65%.

[0039] Comparative Example 2 The substrate and anti-counterfeiting layer were prepared in the same manner as in Example 1. Two different adhesives were prepared: adhesive A (high crosslinking formulation) and adhesive B (low crosslinking formulation). First, adhesive A (10 μm dry film) was applied to the anti-counterfeiting layer and allowed to dry completely for crosslinking; then adhesive B (15 μm dry film) was applied to its surface and dried.

[0040] Comparative tape E was prepared. Although it has a difference in modulus between the upper and lower layers, there is a clear physical interface between the two layers of adhesive.

[0041] Comparative Example 3 Step S1 in Example 1 (i.e., without coating the TPU buffer layer) is omitted. The VOID anti-counterfeiting pattern is printed directly on the PET substrate, followed by applying gradient pressure-sensitive adhesive according to steps S3 and S4 of Example 1 and then performing UV single-sided irradiation.

[0042] A control tape F was prepared. It has a gradient adhesive layer inside, but lacks a buffer structure between the substrate and the adhesive.

[0043] Test case Test Example 1: 90-degree right-angle constant temperature and humidity anti-warping accelerated test Test objective: To simulate the effect of high temperature and high humidity environment on the edge lifting of tape in logistics transportation, and to verify the synergistic anti-lifting effect of "internal stress self-adaptive layer" and "gradient pressure sensitive adhesive".

[0044] Experimental tools: standard B-type corrugated cardboard box (uncoated surface), 2kg standard pressure roller, constant temperature and humidity test chamber, vernier caliper (accuracy 0.01mm).

[0045] Operating steps: 1. Cut the tape to 25mm x 150mm; 2. Attach the tape to the right-angle edge of the carton, ensuring that the long axis is perpendicular to the corner line and that the tape is applied to both sides with equal length; 3. Use a 2kg standard pressure roller to roll back and forth 3 times at a speed of 300mm / min to ensure full saturation; 4. Place the sample in a test chamber at 60 degrees Celsius and 85% relative humidity and place it vertically for 72 hours.

[0046] Evaluation criteria: Use vernier calipers to measure the horizontal projection distance between the curled-up end of the tape and the surface of the carton (unit: mm).

[0047] Test Example 2: Comprehensive Test of 180-Degree Dynamic Peeling Force and Character Clarity Test objective: To verify the ability of the high cohesive region to lock onto the fracture interface at the moment of peeling.

[0048] Experimental standard: Refer to GB / T2792-2014 standard.

[0049] Operating steps: Attach the sample to the surface of a standard stainless steel plate or carton and let it stand for 24 hours; use a universal tensile testing machine to peel it 180 degrees at a constant speed of 300 mm / min; record the average tensile force (N / 25 mm) during the peeling process.

[0050] Character display rating: 5 points (Excellent): The hidden pattern (VOID) is fully displayed, the edges of the text are sharp straight lines, the adhesive layer is completely free of stringing, and no adhesive residue can be observed with the naked eye.

[0051] 3 points (Good): The pattern is more than 90% visible, the edges are slightly jagged, and there is a very small amount of fine filamentous glue residue.

[0052] 1 point (poor): The lettering is incomplete and uneven, and there is severe glue stringing at the peeling interface, making the lettering blurry and illegible.

[0053] Test Example 3: Assessment of Substrate Integrity (Fiber Breakage Rate) Test objective: To verify whether the low cross-linked structure of the "high wetting zone" can achieve "fiber-free" peeling under strong adhesion.

[0054] Operating steps: 1. After the peeling process of test example 2 is completed, visually sample the attached area of ​​the carton; 2. Use a high-magnification magnifying glass to observe whether wood pulp fibers are removed from the surface of the carton.

[0055] Quantitative calculation: Fiber breakage rate = (surface area torn / total attached area) multiplied by 100%.

[0056] Test Example 4: Interlaminar Cohesive Strength (Delamination Risk) Test Test objective: To verify whether the adhesive layer produced by the integrated gradient curing process is stronger than that produced by the traditional two-layer composite process.

[0057] Operating steps: 1. Use a high-speed peeling method (peeling speed increased to 2000 mm / min); 2. Observe the fracture location of the adhesive layer. If intralayer tearing occurs, it indicates that the gradient transition is discontinuous; if the adhesive layer remains intact, it indicates that the in-situ generation of the gradient structure is effective.

[0058] Experimental Data Summary Table

[0059] in conclusion: Comparative Example 1 used a uniform cross-linked adhesive layer. Due to the excessively high overall viscosity of the adhesive layer, the peel force exceeded the bonding force of the cardboard surface, resulting in 65% of the cardboard fibers being violently torn, and the anti-counterfeiting lettering being covered with paper scraps and severely stringing. Example 1, through gradient curing, achieved a perfect balance of "firm adhesion and easy tearing" by being soft on the surface side (without fiber breakage) and hard on the anti-counterfeiting side (without stringing).

[0060] Although Comparative Example 2 also used a double-layer coating with one soft side and one hard side, it employed a physical double-layer coating. Under high-speed peeling force, the two layers of adhesive underwent self-tearing (delamination) due to stress concentration. The single-layer gradient curing process in Example 1, on a microscopic level, represents a continuous transition of molecular chains, completely eliminating the risk of delamination.

[0061] In Comparative Example 3, which lacked a TPU buffer layer, the internal stress of the rigid PET substrate was released under high temperature and humidity conditions of 60°C, directly pulling the underlying adhesive and causing a lift failure of up to 5.5mm. In contrast, Example 1, after introducing a buffer layer, successfully dissipated the rebound stress, achieving an excellent performance of 0 lift after 72 hours.

[0062] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A type of anti-curling and anti-counterfeiting tape, characterized in that, From top to bottom, it includes a substrate layer, an anti-counterfeiting pattern layer, and a pressure-sensitive adhesive layer with a functional gradient structure; The pressure-sensitive adhesive layer is an integrally molded single-layer structure, and in the thickness direction perpendicular to the plane of the substrate layer, the cohesive strength of the pressure-sensitive adhesive layer exhibits an asymmetric gradient distribution. The pressure-sensitive adhesive layer includes: High cohesion region: The chemical cross-linking density of the region near the anti-counterfeiting pattern layer keeps the elastic modulus of the region within a preset range, so as to suppress the elastic stringing deformation of the colloid under the action of peeling force, so as to force the peeling interface to lock at the bonding surface between the anti-counterfeiting pattern layer and the pressure-sensitive adhesive layer. High wetting area: The side away from the anti-counterfeiting pattern layer and used to contact the object to be applied, has a lower chemical cross-linking density than the high cohesion area, so as to wet the surface of the object to be applied through the deformation of the molecular chain and absorb the elastic recovery stress generated by the substrate layer.

2. The anti-curling and anti-counterfeiting tape according to claim 1, characterized in that: The pressure-sensitive adhesive layer has a continuously distributed crosslinking density transition section between the high cohesive region and the high wetting region.

3. The anti-curling and anti-counterfeiting tape according to claim 1, characterized in that: An internal stress self-adaptive layer is provided between the substrate layer and the anti-counterfeiting pattern layer; the internal stress self-adaptive layer is composed of an elastomer coating, whose Young's modulus is less than that of the substrate layer but greater than that of the high cohesive region of the pressure-sensitive adhesive layer.

4. The anti-curling and anti-counterfeiting tape according to claim 1, characterized in that: The pressure-sensitive adhesive layer has a gel fraction of G1 on the high cohesion side and a gel fraction of G2 on the high wetting side, satisfying the following: the difference between G1 and G2 is greater than or equal to 30%; and the value of G1 ranges from 75% to 95%.

5. The anti-curling and anti-counterfeiting tape according to claim 3, characterized in that: The internal stress self-adaptive layer is a modified thermoplastic polyurethane (TPU) coating with a thickness of 5μm-15μm.

6. The anti-curling and anti-counterfeiting tape according to claim 1, characterized in that: The substrate layer is a biaxially stretched polyester film or a biaxially stretched polypropylene film with a thickness of 15μm-35μm.

7. The anti-warping and anti-counterfeiting tape according to claim 1, characterized in that: The anti-counterfeiting pattern layer is formed by partial printing of UV-curable release ink. After curing, the release ink forms a preset peel force difference with the high cohesion area of ​​the pressure-sensitive adhesive layer.

8. A method for manufacturing an anti-curling and anti-counterfeiting tape as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Prepare an anti-counterfeiting pattern layer on the surface of the substrate layer; S2. Apply a pressure-sensitive adhesive containing a photoinitiator to the surface of a substrate with an anti-counterfeiting pattern layer; S3. Gradient curing: A single wavelength ultraviolet light source is used to irradiate the pressure-sensitive adhesive from the side of the substrate layer. By utilizing the energy attenuation effect of ultraviolet light in the thickness direction of the pressure-sensitive adhesive layer, a crosslinking density gradient is induced in a single pressure-sensitive adhesive layer. After curing, a pressure-sensitive adhesive layer with functional gradient is formed.

9. The manufacturing method according to claim 8, characterized in that: The pressure-sensitive adhesive liquid in step S2 includes an acrylate prepolymer, an isocyanate crosslinking agent, and a specific wavelength photoinitiator in a mass fraction of 1.0%-4.0%; the wavelength of the ultraviolet light source matches the absorption wavelength of the photoinitiator.

10. The anti-curling and anti-counterfeiting tape according to claim 3, characterized in that: The internal stress self-adaptive layer, the high cohesive region of the pressure-sensitive adhesive layer, and the high wetting region of the pressure-sensitive adhesive layer satisfy the modulus gradient matching logic. It satisfies: E0 > E1 > E2; Where E0 is the elastic modulus of the self-adaptive internal stress layer, E1 is the elastic modulus of the high cohesion region, and E2 is the elastic modulus of the high wetting region.

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