Preparation method of a breakable anti-counterfeiting RFID tag and breakable glue formula thereof

Abstract

The application discloses a preparation method of a fragile anti-fake RFID label and a fragile adhesive formula thereof and belongs to the technical field of radio frequency identification anti-fake labels. The fragile adhesive composition comprises, in weight parts, 30-50 parts of an acrylate copolymer, 15-25 parts of a rosin modified resin, 10-20 parts of a terpene resin, 5-15 parts of a compound inorganic filler and 2-5 parts of an isocyanate curing agent. Through resin system compounding, stress induction of nano fillers and precise regulation of crosslinking density, the balance between pressure-sensitive adhesive performance and cohesive brittleness is achieved. The preparation method comprises the following steps: adhesive liquid preparation, three-stage gradient temperature coating and drying, RFID antenna preparation, chip flip-chip welding, hot-pressing compounding and curing and die cutting processes. The layered structure of the label is obtained by adopting double-side fragile adhesive to hold the antenna. When the label is peeled off by external force, the adhesive layer is cohesively and fragmentally broken and simultaneously drives the antenna to be irreversibly broken, so that the radio frequency function is permanently disabled. The label has reliable adhesive performance, excellent weather resistance and component compatibility, has a high anti-fake level and is suitable for industrialized and large-scale production.

Description

Technical Field

[0001] This invention relates to the field of radio frequency identification anti-counterfeiting label technology, specifically to a method for preparing a disposable fragile anti-counterfeiting RFID tag that achieves non-transferability through controllable brittle fracture of the adhesive layer, and the formula for the fragile adhesive. Background Technology

[0002] Radio Frequency Identification (RFID) technology, with its advantages of non-contact reading, strong group reading capability, and large information capacity, has been widely used in fields such as product anti-counterfeiting and traceability, asset management, and logistics supervision. For high-value products such as premium wines, cigarettes, luxury goods, and pharmaceuticals, preventing the tags from being completely removed and reused is a core requirement of anti-counterfeiting functionality.

[0003] Existing fragile RFID tag technology has three main drawbacks: Firstly, it is difficult to balance adhesive reliability with fragile anti-counterfeiting features. Lowering the cohesive strength of the adhesive layer in pursuit of a fragile effect will cause the label to easily peel off and detach during normal storage, transportation, and high and low temperature cycles. On the other hand, if the adhesive strength is increased, the toughness of the adhesive layer will increase simultaneously, resulting in the complete transfer of a large piece of adhesive film during peeling, thus losing the anti-counterfeiting function.

[0004] Secondly, the anti-counterfeiting layer is shallow. Most solutions rely solely on the fragile paper face material to achieve physical damage, but the RFID antenna layer often remains intact after the face material is broken, and it can still be identified by high-frequency reading and writing, posing a risk of being transferred and reused; moreover, fragile paper is prone to natural damage when damp, resulting in insufficient environmental reliability.

[0005] Third, the consistency of the preparation process is poor. Existing brittle adhesive formulations have poor batch stability, large fluctuations in coating thickness, uneven fragility of labels in different locations, low yield in large-scale production, and difficulty in meeting the requirements of industrial applications.

[0006] Therefore, developing a fragile adhesive system and a matching label manufacturing process that combines reliable adhesion, thorough anti-counterfeiting effect, and mass production stability is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a fragile adhesive composition that achieves a balance between pressure-sensitive adhesive performance and cohesive brittleness through resin matrix compounding, synergistic tackifying resins, stress induction of nanofillers, and precise control of crosslinking density. This ensures that the label does not fall off during normal use, while also preventing pulverizing cohesive damage upon removal.

[0008] This invention also provides a corresponding label preparation method and a layered label structure. Through the structural design of holding the antenna with double-sided fragile adhesive layers, the peeling force is directly transmitted to the antenna layer through the cracking of the adhesive layer, causing the antenna structure to break, thus achieving a triple anti-counterfeiting effect of "adhesive layer breakage + antenna breakage + functional failure".

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a fragile adhesive composition comprising, by weight, 30-50 parts of acrylate copolymer, 15-25 parts of rosin-modified resin, 10-20 parts of terpene resin, 5-15 parts of compounded inorganic filler, and 2-5 parts of isocyanate curing agent.

[0010] Furthermore, the acrylate copolymer is a ternary random copolymer of butyl acrylate (soft monomer), methyl methacrylate (hard monomer), and acrylic acid (functional monomer), with a glass transition temperature (Tg) of -20 to 10°C, a weight-average molecular weight of 200,000 to 600,000, and a carboxyl value of 10 to 25 mg KOH / g. This Tg range keeps the adhesive layer in a highly elastic state at room temperature, possessing the basic wetting and adhesion capabilities of pressure-sensitive adhesives; simultaneously, the rigidity of the matrix is ​​controlled by the proportion of hard monomers, and the brittleness is improved in conjunction with subsequent components. The carboxyl groups provide active sites for the crosslinking reaction and also enhance adhesion to polar substrates.

[0011] Furthermore, the rosin-modified resin is rosin glycerol ester or rosin pentaerythritol ester, with a softening point of 80–120℃ and an acid value ≤10mgKOH / g; the terpene resin is α-pinene terpene resin, with a softening point of 90–110℃. The rosin-modified resin has strong polarity, improving the initial tack and holding power of the adhesive layer on polar substrates such as metals, glass, and plastics; the terpene resin has excellent compatibility with acrylates, and its rigid structure can significantly improve the cohesive strength and brittleness of the system. Controlling the mass ratio of the two to 1.2–2:1 achieves a precise balance between adhesive strength and cohesive brittleness.

[0012] Furthermore, the compounded inorganic filler is composed of nano-calcium carbonate and fumed silica in a mass ratio of 2–4:1, with an average particle size of 20–100 nm. The filler particles form widespread stress concentration points within the polymer matrix. Under peeling force, microcracks rapidly initiate and branch at the filler-matrix interface, causing the adhesive layer to transition from ductile tearing to brittle fragmentation. Nano-calcium carbonate provides the basic stress points and improves heat resistance; fumed silica constructs a three-dimensional network structure, enhancing the crack propagation effect and simultaneously imparting thixotropy to the adhesive, improving coating processability.

[0013] Furthermore, the isocyanate curing agent is hexamethylene diisocyanate (HDI) trimer or isophorone diisocyanate (IPDI) trimer, with an NCO content of 18%–22%. The curing agent reacts with the carboxyl and hydroxyl groups of the copolymer to form a three-dimensional cross-linked network, constraining molecular chain slippage and improving cohesive strength and weather resistance; controlling the gelation rate within the range of 70%–85% ensures both brittleness and avoids excessive cross-linking that could lead to loss of adhesion and processing breakage.

[0014] Furthermore, the fragile adhesive composition also includes 1-3 parts of plasticizer, 0.5-2 parts of antioxidant, and an appropriate amount of organic solvent. The plasticizer finely adjusts the flexibility of the adhesive layer to avoid edge chipping during die-cutting; the antioxidant inhibits thermo-oxidative aging and extends service life; the mixed solvent adjusts the solid content and evaporation rate of the system to suit the coating process.

[0015] Secondly, the present invention provides a method for preparing a fragile anti-counterfeiting RFID tag, comprising the following steps: S1 adhesive preparation: Weigh each component according to the formula, first dissolve the resin matrix, then disperse the filler and additives, and finally add the curing agent and filter to obtain a uniform and fragile adhesive. S2 Coating and Drying: The adhesive is applied to the release substrate using a slot coating process, and then dried in three stages with a gradient temperature to form a fragile adhesive layer with uniform thickness. S3 antenna fabrication: A UHF band RFID antenna circuit is fabricated on the surface of a flexible substrate, and an RF chip is bonded by a flip-chip bonding process; S4 Composite Molding: The fragile adhesive layer is precisely aligned with the antenna substrate and then hot-pressed to form an integrated composite. S5 Post-processing: The composite is cross-linked and cured by constant temperature curing, and then the finished label is obtained by precision die-cutting and waste removal slitting.

[0016] Thirdly, the present invention provides a fragile anti-counterfeiting RFID tag, comprising a face material layer, a first fragile adhesive layer, an RFID antenna chip layer, a second fragile adhesive layer, and a release liner layer stacked sequentially; the double-sided fragile adhesive layer clamps the antenna structure, so that when the tag is subjected to a peeling force, the cohesive fracture of the adhesive layer directly causes the antenna metal traces to break mechanically, the chip electrical connection to permanently fail, and the tag cannot be reused.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Strong anti-counterfeiting measures: The antenna is held in place by double-sided fragile adhesive. When the adhesive is removed, the adhesive layer will 100% undergo cohesive brittle fracture with an average fragment size of <5mm. At the same time, stress transfer will cause the antenna metal layer to break, resulting in permanent failure of the radio frequency function. This completely eliminates the possibility of transfer and reuse, and the anti-counterfeiting level is far higher than that of single-face material fragile solutions.

[0018] 2. Balanced and reliable adhesion performance: The 180° peel strength of the adhesive layer is stable at 2-8 N / 25 mm. It has good adhesion to a variety of substrates such as paper, plastic, glass, and metal. There is no risk of edge curling or delamination under normal storage and transportation and high and low temperature cycling, which meets the requirements for industrial use.

[0019] 3. Excellent weather resistance and stability: The three-dimensional cross-linked network, combined with nanofillers and antioxidants, maintains stable performance in a wide temperature range of -20℃ to 85℃; after 72 hours of damp heat aging at 60℃ and 90%RH, the peel strength retention rate is ≥85%, and the fragility does not decrease significantly.

[0020] 4. Excellent component compatibility: The formula is neutral and free of halogens and strong acid components. Long-term contact between copper / silver antennas and chip pads does not cause electrochemical corrosion. After 30 days of aging, the sheet resistance change rate is <3% and the reading distance attenuation is <0.5dB.

[0021] 5. Mature mass production process: The entire process adopts continuous roll material processing, with a slit coating thickness tolerance of ≤±1μm, a composite alignment accuracy of ≤±0.15mm, good batch performance consistency, and a production yield of ≥98%, making it suitable for large-scale industrial production. Attached Figure Description

[0022] Figure 1 This is a process flow diagram for the preparation of the fragile anti-counterfeiting RFID tag of the present invention; Figure 2 This is a schematic diagram of the layered structure of the fragile anti-counterfeiting RFID tag of the present invention.

[0023] In the diagram: 1. Face material layer; 2. First fragile adhesive layer; 3. RFID and antenna chip layer; 4. Second fragile adhesive layer; 5. Release paper layer. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments and experimental data. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and operation processes, but the scope of protection of the present invention is not limited to the following embodiments.

[0025] I. Formulation Design Mechanism and Parameter Selection Basis The core design concept of this invention's fragile adhesive is: using soft acrylic pressure-sensitive adhesive as the base to ensure basic adhesion and wetting ability, improving the system's rigidity and cohesive strength through high softening point tackifying resin, introducing nano-composite fillers to construct a stress concentration network to induce brittle fracture, and using precise crosslinking density to constrain molecular chain slippage, ultimately achieving a balanced effect of "pressure-sensitive adhesion at room temperature and brittle fracture upon peeling".

[0026] (a) acrylate copolymer matrix design Acrylic ester copolymers are the foundation of adhesive film formation and properties. Their Tg, molecular weight and functionality directly determine the viscoelasticity and brittle matrix of the adhesive layer.

[0027] This invention selects a terpolymer with a Tg of -20 to 10℃. When the Tg is below -20℃, the matrix is ​​too soft, the molecular chains are too mobile, and a large amount of energy is dissipated during peeling due to plastic deformation, making it difficult to form brittle fragments, resulting in larger fragment sizes. When the Tg is above 10℃, the matrix is ​​too rigid, the initial tack at room temperature is insufficient, the wetting of the substrate surface is slow, the bond strength rises slowly after bonding, and edge lifting is likely. The -20 to 10℃ range keeps the adhesive layer in a highly elastic state at room temperature, providing both sufficient pressure sensitivity for rapid bond establishment and a certain degree of matrix rigidity, thus providing a basis for the subsequent embrittlement of the components.

[0028] The weight-average molecular weight should be controlled between 200,000 and 600,000. If the molecular weight is too low, the cohesive strength will be insufficient, and the adhesive layer will be prone to stringing and uneven residual adhesive; if the molecular weight is too high, the viscosity of the adhesive will be too high, the coating leveling will be poor, and excessive molecular chain entanglement will increase toughness and offset the brittleness-inducing effect.

[0029] A carboxyl group value of 10–25 mg KOH / g provides active sites for cross-linking reactions and enhances adhesion to metals and polar plastics through polar groups. If the carboxyl group value is too low, there are insufficient cross-linking points, making it difficult to meet the cohesive strength requirements; if the carboxyl group value is too high, the cross-linking density is too large, making the adhesive layer prone to brittleness and reducing water resistance.

[0030] (II) Synergistic Mechanism of Compound Tackifying Resins Tackifying resins play a dual role of "enhancing adhesion and controlling brittleness". The combination of two resins can achieve a performance balance that cannot be achieved by a single resin.

[0031] Rosin-modified resins are highly polar, containing ester and hydroxyl groups, which can form hydrogen bonds with polar substrates, significantly improving initial tack and peel strength; however, their own brittleness is generally low, and excessive addition will reduce the cohesive strength of the system. Terpene resins have excellent compatibility with acrylates, and their rigid polycyclic structure can effectively improve the system modulus and cohesive brittleness, but their improvement on adhesion to polar substrates is limited.

[0032] The mass ratio of rosin to terpene should be controlled at 1.2–2:1. Rosin is the primary component to ensure the lower limit of adhesion, while terpene is the secondary component to regulate cohesive brittleness, ensuring that the adhesive strength of the adhesive layer is always greater than its own cohesive strength, and that the failure mode during peeling is consistently cohesive failure. When the ratio is below 1.2:1, the proportion of terpene is too high, resulting in insufficient adhesive strength and easy interfacial peeling; when the ratio is above 2:1, the proportion of rosin is too high, resulting in insufficient cohesive brittleness, and peeling results in large-scale tearing rather than pulverized fragmentation.

[0033] The total amount of resin used is 50% to 90% of the matrix. If the amount is too low, the effects of increasing viscosity and brittleness will be insufficient. If the amount is too high, the compatibility of the system will decrease, precipitation will easily occur, and the adhesive layer will become powdery after long-term aging.

[0034] (III) Stress Concentration and Embrittlement Mechanism of Composite Fillers Inorganic fillers are key components for achieving "fragmentation". According to the theory of brittle fracture, there is a huge difference in modulus between the filler and the polymer matrix. Under the action of external force, a local stress field is formed around the filler. When the stress exceeds the critical cracking stress of the matrix, microcracks initiate at the interface and propagate rapidly.

[0035] The particle size is controlled between 20 and 100 nm. If the particle size is less than 20 nm, the particle specific surface area is too large and it is easy to agglomerate, which cannot form an effective stress concentration point and the crack initiation energy threshold is high; if the particle size is greater than 100 nm, the filler becomes a macroscopic defect, which is easy to crack but will cause the adhesive layer to break when it is bent normally, resulting in a decrease in service life and reliability.

[0036] Nano-calcium carbonate and fumed silica are blended at a ratio of 2 to 4:1. Spherical nano-calcium carbonate provides uniformly distributed stress points, ensuring consistent fragmentation across the entire adhesive layer. The native particles of fumed silica are nanoscale, forming three-dimensional aggregates through hydrogen bonding, which significantly increases the interface area and the number of micro-defects, enhancing the crack bifurcation effect and resulting in finer fragments. A ratio lower than 2:1 results in excessive fumed silica, leading to overly strong thixotropic adhesive and poor coating flow; a ratio higher than 4:1 results in insufficient stress network density and larger fragment sizes.

[0037] (iv) Precise control of crosslinking density The cross-linking of isocyanates forms a three-dimensional network, which confines the slippage and orientation of linear molecular chains within a limited range, preventing microcracks from dissipating energy through molecular relaxation after initiation, thus allowing them to propagate and penetrate at high speed.

[0038] This invention controls the gelation rate to be between 70% and 85%. If the gelation rate is below 70%, the cross-linking is insufficient, the molecular chains can slip significantly, and the adhesive layer exhibits tough tearing, high elongation at break, and large fragments. If the gelation rate is above 85%, the cross-linking is excessive, the adhesive layer is too hard, the pressure sensitivity is significantly reduced, the initial tack is insufficient, and the edges are prone to breakage during die-cutting, resulting in a lower yield.

[0039] The curing agent dosage of 2-5 parts corresponds to the gelation rate range mentioned above. An aliphatic isocyanate trimer is selected, which is resistant to yellowing, has moderate reactivity, and provides a pot life of ≥8 hours, meeting the requirements of continuous industrial production.

[0040] (V) Summary of Overall Synergistic Effect The four components do not act independently, but rather form a synergistic system: the acrylate matrix provides the foundation for pressure-sensitive adhesion and film-forming properties; the compounded tackifying resin enhances adhesive strength and improves system rigidity; the nanofiller constructs a stress concentration network, inducing cohesive failure from "large-scale tearing" to "fragmentation"; and the crosslinking agent constrains molecular chain movement, solidifying the brittle fracture mode. The synergistic effect of these four components stabilizes the elongation at break of the adhesive layer at 10%–30%, and the 180° peel strength at 2–8 N / 25 mm, simultaneously satisfying both adhesive reliability and fragile anti-counterfeiting properties.

[0041] II. DETAILED EMBODIMENT OF PREPARATION PROCESS This embodiment completely describes the entire preparation process based on the formula of Embodiment 2, and the process flow is shown in Figure 1 .

[0042] (I) S1 Glue Preparation 1. Resin dissolution stage: Weigh acrylate copolymer, rosin glyceride and terpene resin according to the formula, add them into a mixed organic solvent, and place in a stirred tank with jacket cooling. Control the temperature at 35°C, the stirring speed at 250rpm, and stir for 50min until the system is completely transparent, with a light transmittance ≥98%. If the temperature is lower than 30°C, the resin dissolves slowly, resulting in low production efficiency; if the temperature is higher than 40°C, solvent volatilization is intensified, leading to large fluctuation of solid content, and moisture is easily introduced to affect the crosslinking reaction.

[0043] 2. Filler dispersion stage: After the resin is completely dissolved, cool the temperature to below 30°C, add nano-calcium carbonate, fumed silica, plasticizer and antioxidant. Increase the rotation speed to 1500rpm for high-speed dispersion for 25min, and control the temperature with jacket cooling water to ≤40°C. After dispersion, the fineness detected by a scraper fineness meter ≤15μm is qualified. If the rotation speed is too low, the filler is unevenly dispersed and aggregates exist; if the rotation speed is too high, the shear heat is excessive, and the polymer molecular chains may be broken, reducing the cohesive strength.

[0044] 3. Curing agent mixing and filtration: Reduce the stirring speed to 200rpm 15min before discharging, slowly add the isocyanate curing agent, and continue stirring for 12min to mix uniformly. The material is discharged after two-stage filtration through a 250-mesh nylon filter screen to remove undispersed aggregates and impurities. The curing agent needs to be added last and mixed under low-speed stirring, which prevents pre-crosslinking caused by heat generated by high-speed shearing, and avoids the increase of glue viscosity and the shortening of the pot life.

[0045] (II) S2 Coating and Drying The glue is uniformly coated on the surface of 80g / m² glassine release paper by a slot die coating process.

[0046] 1. Coating parameters: The dry glue thickness is accurately controlled to 20±1μm through the pumping flow rate and the running speed, and the coating running speed is 15m / min. The transverse thickness difference of slot die coating is ≤±0.5μm, and the consistency of the performance of the whole roll is far better than that of blade coating, which avoids the decrease of frangibility caused by excessive local thickness.

[0047] 2. Three-stage gradient drying: After coating, the material enters a three-stage oven with a total length of 15m.

[0048] First stage: 60°C, 35s residence time: In the constant-rate drying stage, 70% to 80% of the solvent is volatilized steadily, which avoids rapid skin formation on the surface that hinders the escape of internal solvent, and prevents pinhole and bubble defects; The second stage is at 80℃ for 25 seconds: the slow-down drying stage, where the remaining solvent continues to evaporate, and the resin molecular chains fully expand and level out to form a dense and continuous film. The third stage, at 100°C for 20 seconds, completely removes residual solvent (residual amount ≤0.5%), completes the shaping of the adhesive layer, and slightly improves the mobility of molecular chains, providing good interfacial adhesion for subsequent lamination.

[0049] After drying, roll it up and set aside for use. The adhesive layer should not have any seepage or sticking.

[0050] (III) S3 antenna fabrication and chip packaging 1. Antenna Fabrication: A 38μm PET film was used as the substrate. Low-temperature curing conductive silver paste was screen-printed using a 350-mesh screen to fabricate a dipole antenna with dimensions of 40mm × 15mm. The resonant frequency was designed to be 930MHz (with allowance for frequency offset due to dielectric loading of the adhesive layer). After printing, the antenna was dried at 130℃ for 3 minutes, resulting in a silver layer thickness of 8–10μm and a sheet resistance ≤0.05Ω / □.

[0051] 2. Chip Flip Bonding: A high-precision flip bonder is used to align the bumps of the ImpinjMonza R6 chip with the antenna pads. The bonding temperature is 200℃, the bonding pressure is 40g, the bonding time is 0.8s, and the ultrasonic power is 1.5W. After bonding, the chip push force is ≥100g, and the contact resistance is ≤2Ω. After bonding, online RF testing is performed, and 100% of dead chips and weak signal defective products are rejected.

[0052] (iv) S4 composite molding Release membrane coated with a fragile adhesive layer and antenna membrane are fed into a dry laminating machine. The photoelectric correction system controls the alignment accuracy to ≤±0.15mm. The laminating roller temperature is 45℃, the linear pressure is 20N / cm, and the travel speed is 12m / min.

[0053] The bonding temperature is slightly higher than the resin's Tg, causing the adhesive layer surface to soften slightly, fully wetting the microscopic irregularities of the antenna surface, eliminating interfacial air, and forming a tight bond. If the temperature is too low, the bond will not be strong and interface separation may easily occur; if the temperature is too high, the adhesive layer will soften excessively, making it prone to overflow under pressure, and may also damage the chip solder joints.

[0054] If a double-sided adhesive label is to be prepared, a second fragile adhesive layer can be coated on the other side of the antenna and then laminated with the face material (PET film, fragile paper, etc.) in a second step.

[0055] (V) S5 curing and die cutting 1. Curing and Crosslinking: The composite roll material is placed in a constant temperature curing chamber and cured at 50°C for 36 hours to allow the isocyanate and functional groups to fully react, achieving a gelation rate of 70%–85%. If the curing temperature is too low or the time too short, the crosslinking will be insufficient, resulting in substandard cohesive strength and brittleness; if the temperature is too high or the time too long, the crosslinking will be excessive, causing the adhesive layer to become brittle and develop high internal stress, making it prone to curling and wrinkling. After curing, the material is left at room temperature for 24 hours to release internal stress before die-cutting.

[0056] 2. Precision Die-cutting: A flatbed die-cutting machine is used for partial die-cutting with a blade angle of 30°, cutting through the face material, adhesive layer, and antenna layer, leaving approximately 10-15μm of release liner thickness. The die-cutting dimensional accuracy is ±0.1mm, with neat edges free of burrs, excess glue, and chips. After die-cutting, waste is removed, slit, inspected, and packaged to obtain the finished label.

[0057] III. Examples and Comparative Examples (a) Formulation Design Five sets of example samples and four sets of comparative samples were prepared according to Table 1 to verify the key roles of each component and parameter.

[0058] Table 1. Formulations of Examples and Comparative Examples (Unit: Parts by Weight)

[0059] Note: The amount of mixed solvent should be slightly adjusted according to the target solid content of the adhesive solution, which is 35% to 45%. The table shows the typical amounts.

[0060] All samples were prepared into double-sided fragile adhesive labels using the aforementioned process, with a face material of 38μm PET and a total dry adhesive thickness of 30μm, and then subjected to performance testing.

[0061] (II) Testing Methods 180° peel strength: GB / T2792-2014, stainless steel plate, 300mm / min, 5 averages; Elongation at break: dumbbell specimen, gauge length 20 mm, tensile rate 300 mm / min; Fragility assessment: Lift the device at a constant speed of 90°, observe the damage pattern, measure the average fragment size, and test the antenna continuity and RF readout function; Moisture and heat resistance: After being placed at 60℃ and 90%RH for 72 hours, the peel strength was retested after recovery, and the retention rate was calculated. Gel ratio: Percentage of insoluble matter after acetone Soxhlet extraction for 24 hours.

[0062] (III) Test Results and Analysis The performance test results are shown in Table 2.

[0063] Table 2 Comparison of Performance Test Results

[0064] Results analysis: 1. Examples 1-5: Peel strength 3.2-7.3 N / 25 mm, meeting industrial bonding requirements; elongation at break 12%-26%; all exhibit cohesive pulverization upon peeling, with fragment size 2.1-3.8 mm; antenna breaks synchronously, resulting in permanent RF function failure; reliable anti-counterfeiting effect. Example 5 has the highest curing agent content, highest gel rate, strongest brittleness, and smallest fragments; Example 3 has the highest resin content and highest peel strength, suitable for high-adhesion applications.

[0065] 2. Comparative Example 1 (Low Tg matrix): Tg = -35℃ resulted in an excessively soft matrix with strong molecular chain mobility, leading to a peel strength of 6.3 N / 25 mm and an elongation at break of 65%. During peeling, ductile tearing occurred, forming a large film. The antenna remained intact and readable, rendering the anti-counterfeiting measures ineffective. This demonstrates that the matrix's Tg range is the core basis for achieving brittleness.

[0066] 3. Comparative Example 2 (Rosin Resin Deficiency): The absence of polar tackifying resin resulted in a peel strength reduced to 1.8 N / 25 mm, insufficient adhesive reliability, and edge lifting during static application. Furthermore, the total amount of tackifying resin decreased, leading to reduced brittleness and increased fragment size. This demonstrates that rosin resin is an essential component for ensuring adhesive performance.

[0067] 4. Comparative Example 3 (without terpene resin): The single rosin resin system exhibited insufficient cohesive brittleness, with an elongation at break increasing to 42%. During peeling, large areas of cohesive tearing occurred, preventing the formation of pulverized fragments. The antenna remained intact, rendering the anti-counterfeiting measures ineffective. This demonstrates that terpene resin is indispensable for controlling cohesive brittleness and ensuring effective pulverization.

[0068] 5. Comparative Example 4 (unfilled system): Lacking stress concentration points, cracks are difficult to initiate and propagate, resulting in a fracture elongation of 55%. Large sections tear during peeling, but the antenna remains intact, completely losing its anti-counterfeiting crushing effect. This demonstrates that the nano-composite filler is key to achieving "crushing."

[0069] IV. Extended Implementation Examples Based on the core formula and process, multiple scenario-specific models can be derived through component fine-tuning: 1. High adhesion type (Example 6): Rosin glycerol ester increased to 28 parts, terpene resin 12 parts, total filler 8 parts, peel strength 7.5N / 25mm, fragment size 3.8mm, suitable for anti-counterfeiting application on rough surfaces and curved substrates.

[0070] 2. Strong and fragile type (Example 7): The total filler content is increased to 18 parts, the proportion of fumed silica is increased, the curing agent is 4.5 parts, the elongation at break is 10%, and the fragment size is 1.8 mm. It is suitable for high anti-counterfeiting level seals.

[0071] 3. Low temperature weather resistant type (Example 8): The plasticizer is replaced with dioctyl adipate (DOA). The peel strength retention rate is ≥80% at -20℃, and the cohesive fragmentation characteristics are still maintained, making it suitable for cold chain logistics and outdoor scenarios in northern winters.

[0072] 4. High temperature resistant type (Example 9): Replaced with high softening point rosin pentaerythritol ester, the curing agent is increased to 4.5 parts, cured for 48 hours, and after aging at 85°C for 72 hours, the strength retention rate is 94%, which is suitable for high temperature scenarios such as automotive parts and outdoor exposure.

[0073] V. Product Anti-counterfeiting Principles and Instructions for Use To use, peel off the release paper, apply the adhesive side of the label to the clean and dry surface of the object to be labeled, press to remove air bubbles, and the maximum adhesive strength will be achieved after 24 hours.

[0074] Anti-counterfeiting principle: When the label is illegally peeled off, the adhesive layer's bonding strength exceeds its cohesive strength, causing breakage within the adhesive layer. Simultaneously, the nanofiller induces rapid propagation and branching of microcracks, shattering the adhesive layer into fine particles. The antenna structure held by the double-sided adhesive layer is subjected to mechanical shearing and pulling as the adhesive layer breaks, resulting in irreversible breakage of the metal traces and permanent failure of the chip's electrical connections. Ultimately, the label is completely destroyed from the adhesive layer to the antenna, losing its radio frequency function entirely and becoming unusable. This achieves a dual physical and electronic anti-counterfeiting system: "tear-and-break, break-and-useless."

[0075] The above description is only a preferred embodiment of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fragile adhesive composition, characterized in that, By weight, it includes the following components: 30-50 parts of acrylate copolymer, 15-25 parts of rosin-modified resin, 10-20 parts of terpene resin, 5-15 parts of compounded inorganic filler, and 2-5 parts of isocyanate curing agent.

2. The fragile adhesive composition according to claim 1, characterized in that, The acrylate copolymer is a terpolymer of butyl acrylate-methyl methacrylate-acrylic acid, with a glass transition temperature of -20 to 10°C, a weight-average molecular weight of 200,000 to 600,000, and a carboxyl value of 10 to 25 mg KOH / g.

3. The fragile adhesive composition according to claim 1, characterized in that, The rosin-modified resin is rosin glycerol ester or rosin pentaerythritol ester, with a softening point of 80-120℃; the terpene resin is α-pinene terpene resin, with a softening point of 90-110℃; the mass ratio of rosin-modified resin to terpene resin is 1.2-2:

1.

4. The fragile adhesive composition according to claim 1, characterized in that, The composite inorganic filler is a mixed filler composed of nano-calcium carbonate and fumed silica in a mass ratio of 2 to 4:1, with an average particle size of 20 to 100 nm.

5. The fragile adhesive composition according to any one of claims 1 to 4, characterized in that, The product, by weight, further comprises 1-3 parts plasticizer, 0.5-2 parts antioxidant, and 15-30 parts organic solvent based on the total weight of all components as described in claim 1; wherein the plasticizer is dioctyl phthalate or tributyl citrate, the antioxidant is a hindered phenolic antioxidant or a phosphite antioxidant, and the organic solvent is a mixed solvent composed of ethyl acetate and toluene in a volume ratio of 1:0.8-1.

2.

6. A method for preparing a fragile anti-counterfeiting RFID tag, characterized in that, Based on the fragile adhesive composition according to any one of claims 1 to 5, the steps include: S1 adhesive preparation: Dissolve the resin components in an organic solvent according to the formula amount, add fillers and additives and disperse evenly, finally add curing agent, mix and filter to obtain fragile adhesive; S2 Coating and Drying: The fragile adhesive liquid is coated onto the surface of the release substrate and dried through a three-stage gradient temperature rise to form a fragile adhesive layer; S3 antenna fabrication: A UHF band RFID antenna circuit is fabricated on the surface of a flexible substrate and then flip-chip bonded to the RFID radio frequency chip. S4 Composite Molding: The release substrate with a fragile adhesive layer is hot-pressed together with the antenna substrate after the chip is bonded to obtain a composite. S5 post-processing: After the composite is cured and cross-linked, it is die-cut to obtain a fragile anti-counterfeiting RFID tag.

7. The preparation method according to claim 6, characterized in that, Step S1 is as follows: First, add the acrylate copolymer, rosin-modified resin, and terpene resin to an organic solvent and stir for 40-60 minutes at 30-40℃ and 200-300 rpm until completely dissolved; then add the compounded inorganic filler, plasticizer, and antioxidant, and disperse at 1200-1800 rpm for 20-30 minutes until the fineness is ≤15μm; finally, add the isocyanate curing agent, stir at low speed for 10-15 minutes to mix evenly, and filter through a 200-300 mesh filter to discharge the material.

8. The preparation method according to claim 6, characterized in that, Step S2 employs a slot coating method, with the dry adhesive thickness controlled at 15–30 μm and the coating speed at 10–20 m / min. The process parameters for the three-stage gradient temperature drying are as follows: the first stage temperature is 55–65℃, with a dwell time of 30–40 s to evaporate 70%–80% of the solvent; the second stage temperature is 75–85℃, with a dwell time of 20–30 s to promote resin leveling and the escape of residual solvent; and the third stage temperature is 95–105℃, with a dwell time of 15–25 s to remove residual solvent and complete the adhesive layer setting.

9. The preparation method according to claim 6, characterized in that, In step S4, the surface temperature of the composite roller is 40-50℃, the composite linear pressure is 15-30 N / cm, the composite speed is 8-15 m / min, and the alignment deviation is ≤ ±0.15 mm; in step S5, the curing temperature is 45-55℃, the curing time is 24-48 h, and the gelation rate of the adhesive layer is 70%-85%.

10. A fragile anti-counterfeiting RFID tag, characterized in that, Prepared by the preparation method according to any one of claims 6 to 9, the label comprises a face material layer, a first fragile adhesive layer, an RFID antenna chip layer, a second fragile adhesive layer, and a release liner layer stacked sequentially; the first fragile adhesive layer and the second fragile adhesive layer are both formed by curing the fragile adhesive composition according to any one of claims 1 to 5; when the label is peeled off by external force, the fragile adhesive layer undergoes cohesive brittle fracture, which simultaneously causes irreversible structural fracture of the RFID antenna layer, resulting in permanent failure of the label's radio frequency function.

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