High-softness washing-resistant sewing type RFID fabric tag based on recycled PET and preparation method of high-softness washing-resistant sewing type RFID fabric tag

Abstract

The invention relates to the cross technical field of radio frequency identification technology and textile engineering, and discloses a high-softness washing-resistant sewing type RFID fabric tag based on recycled PET and a preparation method. Comprising the following steps that the tag comprises a fabric base body formed by a special skin-core structure recycled PET composite fiber, a flexible conductive yarn woven into the base body to form an antenna, and an RFID chip module electrically connected with the antenna. The composite fiber is characterized in that the skin layer of the composite fiber is low-melting-point recycled PET, and the core layer of the composite fiber is standard-melting-point recycled PET. According to the preparation method, the fabric integrated with the antenna and the chip is subjected to accurate hot pressing treatment, so that the skin layer part of the fiber is selectively melted, and a three-dimensional physical anchoring network is formed in the fabric. The problems that in the prior art, due to the fact that an adhesive film is used, a label is stiff, air permeability is poor, and washing resistance is insufficient are fundamentally solved, and the finished product label has excellent softness, high reliability and excellent durability at the same time.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of radio frequency identification technology and textile engineering, and particularly relates to a high-soft wash-resistant sewable RFID fabric label based on recycled PET and a preparation method. BACKGROUND

[0002] As a non-contact automatic identification technology, the radio frequency identification technology has been widely applied in the fields of logistics management, asset tracking, anti-counterfeiting and traceability. In recent years, with the rapid development of intelligent clothing and textile rental management (such as hotel linen and workwear washing) markets, integrating the RFID function into textiles to form a sewable and wash-resistant fabric label has become an important technical direction in the industry.

[0003] An ideal RFID fabric label not only needs to have stable and reliable long-distance reading and writing performance, but also must be able to withstand multiple and harsh industrial washing, drying and ironing processes while maintaining the softness, air permeability and comfort matching the clothing itself to avoid negative effects on the wearing experience.

[0004] At present, the mainstream technical solution to realize the function of the RFID fabric label is generally based on a composite laminated structure of multiple layers of materials. This method generally involves hot-pressing and bonding a pre-made functional core layer (i.e. Inlay) containing an RFID chip and an antenna with upper and lower two pieces of fabric substrates through one or more layers of hot melt adhesive films (such as TPU, PES or PA, etc.). However, this structure relying on an independent adhesive film layer inherently has an irreconcilable contradiction. In order to ensure sufficient bonding strength to resist the mechanical peeling force in the washing process, a relatively thick or strong adhesive film is often needed, but this inevitably forms a continuous, air-tight rigid layer inside the label, resulting in a stiff and poor air-permeability of the finished label, which directly affects the comfort of the clothing.

[0005] More critically, the long-term reliability of this multi-layer heterogeneous material composite structure faces severe challenges. In the repeated washing, rubbing and high-temperature environment, the macroscopic bonding interface between the fabric, the adhesive film and the functional core layer due to the difference in material physical properties becomes a weak link of the entire structure. The penetration of moisture, the erosion of chemical detergents and the repeated stress will accelerate the degradation and aging of the adhesive layer, which is prone to cause the delamination and blistering inside the label, and eventually lead to the fracture of the connection point between the antenna and the chip, resulting in permanent failure of the label function.

[0006] To solve the partial defects of the lamination method, a scheme of directly weaving or embroidering the conductive yarn into the fabric to form an antenna and then attaching the chip on it also appears. Although this way improves the flexibility of the label to some extent, it transfers the technical difficulty to the reliable fixation and packaging of the electrical connection between the chip and the flexible antenna. This small and rigid connection point on the flexible fabric substrate is prone to metal fatigue fracture and becomes a new failure point under repeated bending and stretching if it lacks effective and durable packaging protection.

[0007] Therefore, there is an urgent need in the art for an innovative technical solution to develop a new type of RFID fabric label. The label can achieve firm packaging and long-term protection of internal electronic components without sacrificing the inherent softness and breathability of the fabric, thereby fundamentally improving the durability and reliability of the label in complex use environments. SUMMARY

[0008] The purpose of the present application is to provide a high-soft wash-resistant sewing type RFID fabric label based on recycled PET and a preparation method, which solves the problem that the existing RFID fabric label is difficult to simultaneously consider the structural softness and comfort and long-term wash resistance.

[0009] To achieve the above purpose, the present application is implemented by the following technical solutions:

[0010] The first aspect of the present application provides a high-soft wash-resistant sewing type RFID fabric label based on recycled PET, which comprises: a fabric substrate formed by interweaving warp yarns and weft yarns; a flexible conductive yarn woven into the interior of the fabric substrate and constituting an antenna pattern; and an RFID chip module electrically connected with the flexible conductive yarn.

[0011] The innovation lies in that the fabric substrate is mainly composed of a special core-sheath structure recycled PET composite fiber. The composite fiber contains a core layer and a sheath layer, and the mass fraction ratio of the core layer to the sheath layer is 80:20 to 60:40. In the structure of the present application, the sheath layer material has undergone a process of re-solidification after melting, forming a three-dimensional physical anchoring network between the fiber network. This network structure microscopically infiltrates, wraps and locks the flexible conductive yarn (antenna) and the base of the RFID chip module inside the fabric, realizing the in-situ packaging and fixation of the electronic components. Since the packaging and fixation functions are realized by a part of the fiber itself rather than relying on an independent adhesive layer, the label structure as a whole maintains the original softness and breathability of the fabric.

[0012] In a preferred embodiment, the core layer of the sheath-core structure recycled PET composite fiber is a standard melting point recycled PET material, with a melting point range set at 250-260℃, to provide a stable structural framework during thermal processing; the sheath layer is a low melting point recycled PET copolymer material, with a melting point range set at 215-230℃, to achieve selective melting without damaging the core layer structure.

[0013] In another preferred embodiment, the flexible conductive yarn is selected from stainless steel fiber multifilament yarn or multi-strand silver-plated copper wire yarn, with a linear density range of 70-120 denier, to ensure that the antenna has good conductivity and bending resistance.

[0014] In still another preferred embodiment, the label has an edge that is closed by thermal fusion, which has a neat structure and can effectively prevent fiber shedding during use and washing.

[0015] The second aspect of the present application provides a method for preparing the above-mentioned high-soft wash-resistant sewable RFID fabric label based on recycled PET, which comprises the following steps:

[0016] S1: Fiber preparation: First, a sheath-core structure recycled PET composite fiber with differential melting point characteristics is prepared, ensuring that the melting point of the sheath layer is significantly lower than that of the core layer.

[0017] S2: Antenna weaving: Then, the prepared sheath-core structure recycled PET composite fiber is used as the main body yarn for weaving, and the flexible conductive yarn is used as the functional yarn. The flexible conductive yarn is directly woven into the fabric according to the preset antenna pattern through computer-controlled weaving process, forming an antenna integrated fabric.

[0018] S3: Chip mounting and bonding: Next, the RFID chip module is mounted at the reserved connection point on the antenna integrated fabric, and the entire fabric is subjected to heat pressing treatment. By precisely controlling the heat pressing temperature, the sheath layer of the sheath-core fiber is melted while the core layer remains solid. The molten sheath layer material flows and penetrates around the electronic components under pressure, and after cooling, it solidifies again, thereby firmly fixing the flexible conductive yarn and the RFID chip module inside the fabric.

[0019] S4: Cutting and forming: Finally, the functional fabric after heat pressing and bonding treatment is cut to obtain an independent label unit with a predetermined shape.

[0020] In a specific embodiment, the step of preparing the sheath layer raw material in step S1 includes: copolymerizing recycled PET with isophthalic acid at a molar ratio of 85:15 to 80:20 for modification, to obtain the desired low melting point characteristics.

[0021] In another specific embodiment, the step of preparing the sheath-core structure recycled PET composite fiber in step S1 further comprises: performing a drawing treatment of 3.2-4.0 times on the as-spun fiber, and performing a heat setting treatment at a temperature of 180-210°C, so as to optimize the mechanical properties and dimensional stability of the fiber.

[0022] In one specific embodiment, in step S2, the warp density and weft density of the antenna integrated fabric are controlled in the range of 70-95 roots / cm, and a specific weaving organization (such as a local long float) is designed in the chip connection area, so that the ends of the conductive yarns can be exposed on the surface of the fabric to form fabric pads for chip mounting.

[0023] In another specific embodiment, the hot pressing treatment in step S3 has the following process parameters: the hot pressing temperature is set to 225-240°C, the applied pressure is 0.3-0.8 MPa, and the pressure holding time is 8-20 seconds.

[0024] In still another specific embodiment, the cutting step in step S4 is performed by laser cutting or ultrasonic cutting, which utilizes the instantaneous thermal effect to fuse and seal the edges of the label at the same time of cutting.

[0025] In summary, the present application has the following at least one beneficial technical effect:

[0026] 1. The RFID fabric label provided by the present application has excellent softness and comfort. The core lies in the use of special sheath-core structure recycled PET fiber, and the use of in-situ hot melt bonding process for packaging, so as to completely abandon the independent hot melt adhesive film which is necessary in traditional technology and causes the rigidity of the label. Since the bonding function is realized by micro-melting of the fiber sheath, the label as a whole retains the original loose porous structure and natural drooping feeling of the fabric, can perfectly fit the clothes, and significantly improves the comfortable experience of the wearer.

[0027] 2. The present application greatly enhances the durability and washing resistance of the label. By accurately controlling the hot pressing process, a solid "three-dimensional physical anchoring network" is formed inside the fabric after the fiber sheath melts. This network infiltrates, wraps and physically locks the flexible conductive yarns and rigid RFID chip modules from the micro level, so that the electronic components and the fabric matrix are integrated. This overall packaging structure without macro interface fundamentally eliminates the common problems of glue opening and delamination of traditional laminated labels under repeated washing and rubbing, and ensures the long-term stability and reliability of the label function.

[0028] 3. This invention significantly simplifies the manufacturing process and improves production efficiency. Its key lies in the integrated design of functions, embedding the adhesive function within the core-sheath fiber structure. This allows multiple process objectives, such as chip packaging, antenna fixation, and structural reinforcement, to be completed simultaneously through a single hot-pressing process. This method eliminates the cumbersome steps of purchasing, storing, cutting, and aligning individual adhesive films in traditional processes, shortening the production flow and reducing material costs and potential process defect risks.

[0029] 4. The label produced by this invention exhibits excellent breathability. Unlike traditional techniques that use continuous adhesive films, resulting in complete blockage of fabric pores, the bonding structure of this invention consists of discrete anchor points formed at the interlacing points of the fiber sheath. This structure ensures a secure seal while maximizing the preservation of the original gaps between fabric fibers, allowing moisture and air to permeate freely, thus guaranteeing good breathability and moisture wicking performance even when used close to the skin.

[0030] 5. This invention meets the requirements of green environmental protection and sustainable development. The core raw material of this technical solution—the core-sheath composite fiber—is made from recycled PET for both its core and sheath layers. This not only effectively utilizes waste plastic resources and reduces dependence on virgin petroleum resources and environmental pollution, but also endows the RFID fabric tag, a consumable product, with sustainable attributes, aligning with the global trend of green manufacturing. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1 The present invention will be further described in detail below.

[0033] This invention provides a highly flexible, washable, sewn-on RFID fabric tag based on recycled PET and its preparation method.

[0034] Example 1

[0035] This embodiment provides a method for preparing a highly flexible and washable sewn RFID fabric tag based on recycled PET. The specific steps are as follows:

[0036] 1. Preparation of functional core-sheath structure rPET fibers:

[0037] Recycled PET was copolymerized with isophthalic acid at a molar ratio of 82:18 to obtain a low-melting-point recycled PET copolymer with a melting point of 222℃, which was used as the skin material.

[0038] Using a composite spinning device, standard recycled PET with a melting point of 255℃ is used as the core layer raw material, and the above-mentioned low-melting-point copolymer is used as the sheath layer raw material. The mass ratio of the core layer to the sheath layer is controlled at 70:30 for melt spinning.

[0039] Nascent fibers were stretched 3.6 times and heat-set at 195°C to obtain 75 denier core-sheath structure rPET composite fibers.

[0040] 2. Weaving of integrated antenna fabric:

[0041] The core-sheath rPET fiber obtained in step 1 is used as the warp and weft yarns, and stainless steel multifilament yarn with a linear density of 95D is selected as the conductive yarn.

[0042] The conductive yarns are woven into the fabric on an electronic jacquard loom according to a preset dipole antenna pattern. The warp and weft density of the fabric are both controlled at 82 yarns / cm. At the predetermined position of the chip, the ends of the conductive yarns are exposed through a warp float structure.

[0043] 3. Chip mounting and in-situ thermal bonding:

[0044] The UHF RFID chip module is attached to the exposed conductive yarn end on the fabric.

[0045] The fabric with the chip attached was placed in a hot press, the hot pressing temperature was set to 232℃, the applied pressure was 0.55MPa, and the holding time was 14 seconds.

[0046] After the pressure holding period, the mixture is cooled to room temperature while maintaining the pressure to complete the bonding process.

[0047] 4. Post-processing and finished product:

[0048] A laser cutting machine is used to cut the bonded fabric into individual label units of the designed size, while simultaneously completing the edge fusion sealing.

[0049] Example 2

[0050] This embodiment provides a method for preparing a highly flexible and washable sewn RFID fabric tag based on recycled PET. The specific steps are as follows:

[0051] 1. Preparation of functional core-sheath structure rPET fibers:

[0052] Recycled PET was copolymerized with isophthalic acid at a molar ratio of 85:15 to obtain a low-melting-point recycled PET copolymer with a melting point of 230℃, which was used as the skin material.

[0053] Using a composite spinning device, standard recycled PET with a melting point of 260℃ is used as the core layer raw material, and the above-mentioned low-melting-point copolymer is used as the sheath layer raw material. The mass ratio of the core layer to the sheath layer is controlled at 80:20 for melt spinning.

[0054] Nascent fibers were stretched 3.2 times and heat-set at 180°C to obtain 150 denier core-sheath structure rPET composite fibers.

[0055] 2. Weaving of integrated antenna fabric:

[0056] The core-sheath rPET fiber obtained in step 1 is used as the warp and weft yarns, and stainless steel multifilament yarn with a linear density of 70D is selected as the conductive yarn.

[0057] The fabric is woven on a multi-arm loom, with conductive yarns woven in to form an antenna. The warp and weft densities of the fabric are both controlled at 70 threads / cm.

[0058] 3. Chip mounting and in-situ thermal bonding:

[0059] The UHF RFID chip module is attached to the pre-reserved connection point on the fabric.

[0060] Place the fabric in a hot press, set the hot pressing temperature to 225℃, apply a pressure of 0.3MPa, and hold the pressure for 8 seconds.

[0061] After the pressure holding period, the pressure is released and the material is allowed to cool naturally to complete the bonding process.

[0062] 4. Post-processing and finished product:

[0063] Using ultrasonic cutting equipment, the bonded fabric is cut into individual label units, and the edges are fused and sealed.

[0064] Example 3

[0065] This embodiment provides a method for preparing a highly flexible and washable sewn RFID fabric tag based on recycled PET. The specific steps are as follows:

[0066] 1. Preparation of functional core-sheath structure rPET fibers:

[0067] Recycled PET was copolymerized with isophthalic acid at a molar ratio of 80:20 to obtain a low-melting-point recycled PET copolymer with a melting point of 215℃, which was used as the skin material.

[0068] Using a composite spinning device, standard recycled PET with a melting point of 250°C is used as the core layer material, and the above-mentioned low-melting-point copolymer is used as the sheath layer material. The mass ratio of the core layer to the sheath layer is controlled at 60:40 for melt spinning.

[0069] Nascent fibers were stretched 4.0 times and heat-set at 210℃ to obtain 70 denier core-sheath structure rPET composite fibers.

[0070] 2. Weaving of integrated antenna fabric:

[0071] The core-sheath rPET fiber obtained in step 1 is used as the warp and weft yarns, and multi-strand silver-plated copper wire yarn with a linear density of 120D is selected as the conductive yarn.

[0072] The fabric is woven on an electronic jacquard loom, with conductive yarns woven in to form an antenna. The warp and weft densities of the fabric are both controlled at 95 yarns / cm.

[0073] 3. Chip mounting and in-situ thermal bonding:

[0074] The UHF RFID chip module is attached to the pre-reserved connection point on the fabric.

[0075] Place the fabric in a hot press, set the hot pressing temperature to 240℃, apply a pressure of 0.8MPa, and hold the pressure for 20 seconds.

[0076] After the pressure holding period, the material is rapidly cooled while maintaining a light pressure to complete the bonding process.

[0077] 4. Post-processing and finished product:

[0078] A laser cutting machine is used to cut the bonded fabric into individual label units, completing the edge fusion sealing.

[0079] Comparative Example 1

[0080] Compared to Example 1, the difference lies in that: instead of using core-sheath structure recycled PET composite fibers, standard recycled PET fibers (melting point 255°C) of the same core material as in Example 1 are used for weaving; and in the hot-press bonding process of step 3, an additional 30μm thick TPU (thermoplastic polyurethane) hot melt adhesive film is added between the integrated antenna fabric and the RFID chip module, followed by hot pressing. All other preparation conditions are the same as in Example 1.

[0081] Comparative Example 2

[0082] The difference from Example 1 is that, in step 1, when preparing the core-sheath structure recycled PET composite fiber, the mass ratio of the core layer to the sheath layer was controlled at 50:50, which exceeds the range defined by this invention. All other preparation conditions were the same as in Example 1.

[0083] Comparative Example 3

[0084] The difference from Example 1 is that in the in-situ hot-melt bonding process of step 3, the hot-pressing temperature is set to 265°C. This temperature is higher than the melting point of the core material (melting point 255°C). All other preparation conditions are the same as in Example 1.

[0085] Comparative Example 4

[0086] Compared to Example 1, the difference lies in that the hot-pressing process in step 3 is omitted. That is, after the RFID chip module is attached to the fabric, no hot-pressing bonding process is performed, and it directly proceeds to the cutting process in step 4. All other preparation conditions are the same as in Example 1.

[0087] Test Example 1: Label Softness Comparison Test

[0088] Experimental instructions

[0089] 1. Experimental objective: To verify the advantages of the present invention in maintaining label softness by quantitatively measuring and comparing the softness of labels prepared according to the present invention with comparative samples prepared using different methods.

[0090] 2. Experimental instruments and samples

[0091] Instrument: YG(B)811D Fabric Cantilever Beam Softness Tester.

[0092] Samples: Labels prepared from Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 respectively.

[0093] 3. Experimental Procedure

[0094] 3.1 Sample Preparation: Randomly select 5 samples from each batch of labels and cut them into standard specimens of 25mm × 150mm along the warp (length) direction. Condition all specimens under standard atmospheric conditions (temperature 20±2℃, relative humidity 65±4%) for at least 4 hours.

[0095] 3.2 Instrument Calibration: In accordance with the instrument operating procedures, calibrate the horizontal platform and the 41.5° inclined plane to ensure accurate zero point.

[0096] 3.3 Sample Testing: Place a sample flat on a horizontal platform, with its long side parallel to the edge of the platform and one end aligned with the scale line on the platform. Start the instrument and move the platform forward at a constant speed, causing the sample to extend beyond the platform to form a cantilever. When the sharp corner of the free end of the sample touches the 41.5° inclined plane, the instrument automatically stops and records the length of the sample extending beyond the platform at this point, which is the bending length (unit: mm).

[0097] 3.4 Data Recording: Test both sides of each sample separately, and take the average value as the bending length of the sample. Record the test results of all 5 samples.

[0098] 3.5 Data processing: Calculate the average bending length of the five specimens in each group (Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3).

[0099] Experimental data

[0100] Table 1. Softness test results of different samples (bending length, unit: mm)

[0101] Sample No. Test 1 Test 2 Test 3 Test 4 Test 5 Average Example 1 31.5 34.2 30.8 33.5 32.1 32.4 Comparative Example 1 58.9 61.2 57.5 63.1 59.8 60.1 Comparative Example 2 65.4 69.1 64.8 70.3 66.2 67.2 Comparative Example 3 85.1 82.6 88.4 84.9 86.3 85.5

[0102] Summarize

[0103] As can be seen from the test results in Table 1, the average bending length of the tag sample prepared in Example 1 is significantly lower than that of the samples in Comparative Examples 1, 2, and 3. This directly demonstrates that the tag prepared by the technical solution provided by this invention has excellent softness. The root of this superior performance lies in the unique structural design and preparation method of this invention. The tag as a whole does not contain any independent, continuous adhesive film layer, and its softness is mainly determined by the flexibility of the fabric matrix itself. Thus, while achieving a secure encapsulation of the internal RFID components, the original soft touch of the fabric is preserved to the maximum extent.

[0104] Compared to Example 1, the sample in Comparative Example 1 exhibited a significantly increased bending length due to the introduction of a TPU hot melt adhesive film as the bonding medium. This is because the TPU film, after hot pressing, forms a continuous polymer film layer with a certain degree of rigidity. This film layer severely restricts the relative movement between fabric fibers, causing the entire label composite to exhibit stiff characteristics similar to laminated paper, thus sacrificing the fabric's softness. This invention, by employing a core-sheath fiber design, utilizes in-situ melting of the fiber sheath to replace the external adhesive film. The molten sheath, upon cooling, forms microscopic anchoring points distributed between the fibers, rather than a continuous macroscopic film layer, thus successfully avoiding the overall hardening problem caused by an independent adhesive layer.

[0105] The test results of Comparative Examples 2 and 3 further highlight the necessity of precisely defining the component ratios and process parameters in the present invention. In Comparative Example 2, the excessively high proportion of the skin material resulted in excessively molten polymer filling almost all the voids in the fabric during hot pressing. In Comparative Example 3, the excessively high hot pressing temperature caused the fiber core to melt as well, completely destroying the fabric's fiber structure. Both situations resulted in the final product transforming from a "fabric" into a rigid plastic sheet with a drastically increased bending length, completely losing the flexibility expected of a fabric label. This conversely demonstrates that only by strictly adhering to the component and process limits defined in this invention can a delicate balance be achieved: selective melting of the skin to provide adhesion while maintaining the core structure to preserve fabric flexibility.

[0106] Test Example 2: Comparative Test of Washability

[0107] Experimental instructions

[0108] 1. The purpose of this experiment is to evaluate the ability of the label prepared by the technical solution provided in this invention to maintain its electrical properties and structural integrity after repeated industrial water washing cycles, and to compare it with samples using traditional adhesive film bonding and samples without bonding treatment.

[0109] 2. Experimental instruments and samples

[0110] Instruments: Wascator FOM71CLS standard drum washing machine, AccuDry standard drum dryer, ThingMagic M6e UHF RFID reader and matching test antenna.

[0111] Samples: Labels were taken from Example 1, Comparative Example 1, and Comparative Example 4, respectively. Ten samples were randomly selected from each group.

[0112] 3. Experimental Procedure

[0113] 3.1 Sample fixing: Each label sample is fixed to the center of a standard cotton carrier fabric with a size of 30cm×30cm by sewing.

[0114] 3.2 Initial Performance Test: Before any washing, an initial performance test was performed on all samples. The samples were placed directly in front of the reader antenna, and the maximum reading distance (in meters) at which 100% successful identification was determined by gradually increasing the distance, and the result was recorded. The initial reading success rate was confirmed to be 100%.

[0115] 3.3 Washing and Drying Cycle: All carrier fabrics with fixed samples, along with the counterweight load, were placed in a standard drum washing machine. Washing was performed at 60°C according to procedure 6A of ISO 6330:2012. After washing, all samples and loads were transferred to a standard drum dryer for medium-temperature drying. One complete "wash-dry" cycle is counted as one cycle.

[0116] 3.4 Periodic Inspection: After completing 5, 10, 20, 30, and 50 washing cycles, all samples were removed. After completely cooling to room temperature, the performance test in step 3.2 was repeated, recording the reading success rate (percentage of successful reads out of 10 tests) and maximum reading distance for each stage. Simultaneously, the label surface was visually and tactilely inspected for blistering, cracking, delamination, and whether the chip was loose or detached.

[0117] Experimental data

[0118] Table 2. Results of washability tests for different samples

[0119]

[0120] Note: Failure indicates a 0% read success rate or irreversible physical damage to the tag.

[0121] Summarize

[0122] The test data in Table 2 clearly show that the tag prepared in Example 1 maintained a very high reading success rate and stable reading distance after 50 rigorous wash-dry cycles, demonstrating excellent wash resistance. In stark contrast, the sample in Comparative Example 1 experienced rapid performance degradation, essentially failing after 30 cycles, while the sample in Comparative Example 4 completely failed in the first few washes. This result strongly demonstrates the significant advantages of the technical solution provided by this invention in ensuring the long-term reliability of RFID fabric tags.

[0123] The superior durability of Example 1 is fundamentally due to its unique "three-dimensional physical anchoring network" structure. During in-situ thermal bonding, the molten fiber sheath material penetrates into the microscopic gaps between the conductive yarn and the chip substrate and re-solidifies, forming countless microscopic anchoring points. This structure allows the electronic components to integrate seamlessly with the fabric matrix, eliminating the macroscopic "interface" present in traditional adhesive structures. Therefore, under the mechanical stress and humid heat of washing, the stress is dispersed throughout the fiber network, and the label deforms as a whole, effectively preventing delamination, peeling, and eventual functional failure caused by stress concentration at the interface.

[0124] Conversely, Comparative Example 1 uses a TPU hot melt adhesive film that forms a clear bonding interface between the fabric and the electronic components. This interface is highly susceptible to hydrolytic aging and fatigue cracking under repeated exposure to moisture, heat, and rubbing, leading to decreased adhesion and ultimately damage to the chip-antenna connection point or antenna detachment, resulting in rapid degradation of its electrical performance. Comparative Example 4, in an extreme case, demonstrates the necessity of the bonding step. Its chip module is merely physically contained through the woven structure without any effective fixing measures. Therefore, under the immense mechanical force of washing, the chip shifts or detaches directly, instantly causing the tag to become completely ineffective.

[0125] Test Example 3: Electrical Performance Stability Test under Physical Stress

[0126] Experimental instructions

[0127] 1. Experimental objective: To quantitatively evaluate the effectiveness of the bonding structure provided by this invention in protecting the connection points between the internal RFID chip and the antenna by simulating repeated bending that may be encountered in actual use, and to compare it with samples that have not undergone bonding treatment.

[0128] 2. Experimental instruments and samples

[0129] Instruments: MIT-type fabric bending resistance tester, ThingMagicM6e UHF RFID reader and matching test antenna.

[0130] Samples: Labels were taken from Example 1 and Comparative Example 4, respectively. Five samples were randomly selected from each group.

[0131] 3. Experimental Procedure

[0132] 3.1 Initial Performance Test: Before the bending test, an initial performance test was performed on all samples. Each sample was placed directly in front of the antenna, and the maximum reading distance (unit: m) that could be stably identified was measured and recorded.

[0133] 3.2 Bending Test: Securely mount the sample onto the fixture of the bending tester, ensuring the center area of ​​the label is on the bending axis. Set the bending angle to ±90° and perform repeated bending at a frequency of 30 times / minute. Each sample undergoes 1000 cycles of bending.

[0134] 3.3 Final performance test: After the bending test is completed, the sample is removed from the testing machine and the performance test is carried out again. The maximum reading distance after bending is measured and recorded.

[0135] 3.4 Data Analysis: For each sample, the attenuation rate of the reading distance was calculated based on the maximum reading distance before and after bending. Attenuation rate (%) = [(Initial reading distance - Reading distance after bending) / Initial reading distance] × 100%.

[0136] Experimental data

[0137] Table 3 Comparison of performance of different samples before and after bending test

[0138] Sample No. Initial reading distance (m) Reading distance after bending (m) Attenuation rate (%) Example 1 - Sample A 6.1 5.8 0.049 Example 1 - Sample B 5.9 5.7 0.034 Example 1 - Sample C 6.2 6 0.032 Comparative Example 4 - Sample A 6 0.8 0.867 Comparative Example 4 - Sample B 6.2 Failure 1 Comparative Example 4 - Sample C 5.9 0.5 0.915

[0139] Note: Failure indicates that the tag cannot be read at all.

[0140] Summarize

[0141] The test results in Table 3 significantly reveal the substantial advantages of the technical solution provided by this invention in resisting physical stress. After undergoing 1000 severe bends, the reading distance of the sample in Example 1 showed only a minimal decrease, demonstrating highly stable performance. In contrast, under the same test conditions, the electrical performance of the sample in Comparative Example 4 deteriorated catastrophically, with the reading distance of most samples plummeting to less than 1 meter, or even completely failing. This fully demonstrates that the thermal bonding step in this invention plays a decisive role in ensuring the structural integrity and functional reliability of the tag under dynamic usage environments.

[0142] The superior bending resistance of the sample in Example 1 is due to the "three-dimensional physical anchoring network" formed by the in-situ thermal bonding process. During hot pressing, the molten fiber sheath material penetrates and encapsulates the rigid RFID chip module base and its connection points with the flexible conductive yarn. After cooling and solidification, these fragile electrical connection points are firmly "cast" into the flexible fiber matrix, forming a cohesive whole that shares the load. When the tag is bent, the stress is effectively dispersed and buffered through the flexible fabric matrix, rather than concentrated on the fragile chip solder joints, thus effectively preventing micro-cracks or breakage at the connection points due to mechanical fatigue.

[0143] In contrast, the sample in Comparative Example 4 lacked the crucial thermal bonding step. Its RFID chip module was merely housed through the physical interweaving structure formed by the fabric during weaving, without effective fixation. When this type of tag was repeatedly bent, relative displacement and misalignment occurred between the flexible fabric and the rigid chip module. This caused all mechanical stress to act directly and repeatedly on the connection point between the chip and the conductive yarn. This stress concentration effect rapidly led to metal fatigue at the connection point, the formation of microcracks, and even complete breakage, resulting in a sharp increase in circuit resistivity or the formation of an open circuit. Ultimately, this manifested as a drastic decrease in tag communication distance until complete failure.

[0144] Test Example 4: Structural and dimensional stability test during processing

[0145] Experimental instructions

[0146] 1. Experimental objective: By comparing the dimensional changes and morphological characteristics of samples under different composition and process conditions after hot pressing, this experiment aims to verify the crucial role of the material ratio and process parameter range defined in this invention in maintaining the structural and dimensional stability of the fabric.

[0147] 2. Experimental instruments and samples

[0148] Instruments: Precision digital caliper, high-precision electronic balance.

[0149] Samples: Fabric samples before hot pressing treatment, corresponding to the preparation schemes of Example 1, Comparative Example 2, and Comparative Example 3, respectively. Three samples were randomly selected from each group.

[0150] 3. Experimental Procedure

[0151] 3.1 Initial State Recording: Before hot pressing, the fabric samples were laid flat. Using a digital caliper, the dimensions of each sample were measured at three different locations along both the length and width directions. The average value was taken as the initial length and width of the sample. Simultaneously, the samples were visually and tactilely evaluated, and their initial fabric shape and softness were recorded.

[0152] 3.2 Hot pressing treatment: The samples were treated according to the hot pressing conditions described in their corresponding Examples 1, 2 and 3.

[0153] 3.3 Final State Record: After the sample has completely cooled to room temperature, its final length and width are measured using the same method. At the same time, the sample is again carefully visually and tactilely evaluated, focusing on whether it maintains the interwoven fabric structure or shows signs of melting, hardening, or clumping.

[0154] 3.4 Data Analysis: Based on the dimensional data before and after hot pressing, the area shrinkage rate of each sample was calculated. Area shrinkage rate (%) = [(initial area - final area) / initial area] × 100%.

[0155] Experimental data

[0156] Table 4 Comparison of dimensional changes and appearance of different samples before and after hot pressing.

[0157]

[0158]

[0159] Summarize

[0160] The test results in Table 4 clearly reveal that only under specific material composition ratios and process parameters can effective bonding be achieved while maintaining the original structural and dimensional stability of the fabric. The sample in Example 1, after hot-pressing, exhibited only extremely low area shrinkage and completely retained its soft form and fiber characteristics as a "fabric." In contrast, the samples in Comparative Examples 2 and 3 showed significant, even catastrophic, dimensional shrinkage and structural damage, demonstrating the scientific validity and necessity of limiting key parameters in this invention.

[0161] The success of Example 1 lies in the precise control of "differential melting." Within the temperature range defined by this invention, the heat is just sufficient to melt the low-melting-point outer layer of the fiber, causing it to flow under pressure and bond to the internal electronic components. Simultaneously, the high-melting-point core layer, serving as the fabric's skeleton, remains solid, acting like a stable three-dimensional network that powerfully supports the overall macroscopic structure of the fabric, effectively suppressing the severe shrinkage that might result from polymer melting. This process provides adhesive strength while perfectly preserving the fabric's basic shape.

[0162] In stark contrast, Comparative Example 3 suffered from excessively high hot-pressing temperatures, exceeding the melting point of the core material. This caused the core, the "skeleton," to melt, leading to the instantaneous collapse of the entire fiber structure and its shrinkage into a hard, plastic mass, completely rendering it unusable as a fabric. Comparative Example 2, on the other hand, suffered from problems with its material composition. Its excessively high proportion of sheath material resulted in the production of excessive melt even at the correct temperature. This excess melt not only completed bonding but also filled the gaps between fibers, densifying the originally loose and porous fabric structure. This caused significant dimensional shrinkage and overall hardening, similarly failing to achieve the desired effect.

[0163] The method for creating a highly flexible, washable, sewn RFID fabric tag based on recycled PET, as described below, can be referred to in conjunction with the method for creating a highly flexible, washable, sewn RFID fabric tag based on recycled PET, as described above.

[0164] Includes the following steps:

[0165] S1: Fiber preparation: A method for preparing a core-sheath structure of recycled PET composite fiber based on a highly flexible and washable sewn RFID fabric tag made from recycled PET, wherein the sheath melting point of the fiber is lower than that of the core.

[0166] S2: Antenna weaving: A high-softness, washable, sewn RFID fabric tag based on recycled PET and its preparation method. The recycled PET composite fiber of the core-sheath structure is used as the main yarn, and the flexible conductive yarn is used as the functional yarn. The flexible conductive yarn is woven into the fabric according to the preset antenna pattern through a weaving process to form an integrated antenna fabric.

[0167] S3: Chip mounting and bonding: A high-softness, washable, sewn RFID fabric tag based on recycled PET and its preparation method are described. An RFID chip module is mounted on the antenna integrated fabric, and the fabric is subjected to hot pressing treatment, so that the sheath of the recycled PET composite fiber of the sheath-core structure melts while the core layer remains solid, and is re-solidified after cooling, thereby fixing the flexible conductive yarn and the RFID chip module inside the fabric.

[0168] S4: Cutting and shaping: A method for preparing highly flexible and washable sewn RFID fabric tags based on recycled PET, which involves cutting the heat-pressed fabric into individual tag units.

[0169] 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 highly flexible, washable, sewn-on RFID fabric tag based on recycled PET, characterized in that, include: A fabric matrix formed by the interlacing of warp and weft yarns; A flexible conductive yarn woven into the fabric matrix and forming an antenna pattern; as well as; An RFID chip module electrically connected to the flexible conductive yarn; The fabric matrix is ​​mainly composed of core-sheath structure recycled PET composite fibers, which include a core layer and a sheath layer. The mass ratio of the core layer to the sheath layer is 80:20 to 60:

40. The sheath layer is melted and then re-solidified to form a three-dimensional physical anchoring network. This network encapsulates and fixes the flexible conductive yarn and the RFID chip module base inside the fabric matrix.

2. The label according to claim 1, characterized in that, The core layer is made of standard melting point recycled PET material with a melting point range of 250–260°C, and the outer layer is made of low melting point recycled PET copolymer material with a melting point range of 215–230°C.

3. The label according to claim 1, characterized in that, The flexible conductive yarn is stainless steel multifilament yarn or multi-strand silver-plated copper wire yarn, with a linear density ranging from 70 to 120 denier.

4. The label according to claim 1, characterized in that, The label has edges that are fused together by a thermal effect.

5. A method for preparing a highly flexible, washable, sewn-on RFID fabric tag based on recycled PET as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Fiber preparation: A method for preparing a core-sheath structure of recycled PET composite fiber based on a highly flexible and washable sewn RFID fabric tag made from recycled PET, wherein the sheath melting point of the fiber is lower than that of the core. S2: Antenna weaving: A high-softness, washable, sewn RFID fabric tag based on recycled PET and its preparation method. The recycled PET composite fiber of the core-sheath structure is used as the main yarn, and the flexible conductive yarn is used as the functional yarn. The flexible conductive yarn is woven into the fabric according to the preset antenna pattern through a weaving process to form an integrated antenna fabric. S3: Chip mounting and bonding: A high-softness, washable, sewn RFID fabric tag based on recycled PET and its preparation method are described. An RFID chip module is mounted on the antenna integrated fabric, and the fabric is subjected to hot pressing treatment, so that the sheath of the recycled PET composite fiber of the sheath-core structure melts while the core layer remains solid, and is re-solidified after cooling, thereby fixing the flexible conductive yarn and the RFID chip module inside the fabric. S4: Cutting and shaping: A method for preparing highly flexible and washable sewn RFID fabric tags based on recycled PET, which involves cutting the heat-pressed fabric into individual tag units.

6. The method according to claim 5, characterized in that, In step S1, the step of preparing the skin material includes: copolymerizing recycled PET with isophthalic acid at a molar ratio of 85:15 to 80:

20.

7. The method according to claim 5, characterized in that, In step S1, the step of preparing core-sheath structure recycled PET composite fiber further includes: stretching the nascent fiber formed after spinning by 3.2 to 4.0 times, and heat setting at a temperature of 180 to 210°C.

8. The method according to claim 5, characterized in that, In step S2, the warp and weft density of the integrated antenna fabric ranges from 70 to 95 threads / cm, and the ends of the conductive yarns are exposed to form fabric pads in the chip connection area through a specific weaving structure.

9. The method according to claim 5, characterized in that, In step S3, the process parameters for hot pressing are: hot pressing temperature of 225-240℃, applied pressure of 0.3-0.8MPa, and holding time of 8-20 seconds.

10. The method according to claim 5, characterized in that, In step S4, laser cutting or ultrasonic cutting is used for cutting, so that the edges of the label are fused and sealed at the same time as cutting.

Images