High-conductivity RFID antenna and preparation process and application thereof

Abstract

The invention relates to the field of radio frequency identification technology, in particular to a high-conductivity RFID antenna and a preparation process and application thereof, and the preparation process comprises the following steps: S1, printing conductive ink on a printing stock, and drying the printing stock through an infrared and hot air combined drying tunnel to obtain an RFID antenna containing a conductive ink layer; s2, calendaring the RFID antenna containing the conductive ink layer to obtain a high-conductivity RFID antenna; the conductive ink is graphene conductive ink. According to the method, firstly, the graphene conductive ink is printed on the printing stock, the graphene conductive ink is promoted to form a uniform and compact conductive ink layer on the printing stock in a mode of combining infrared drying and hot air drying, and then through calendering treatment, the contact resistance and pores between graphene sheet layers are remarkably reduced; and a penetrating and efficient multi-dimensional conductive network is constructed, so that the square resistance of the RFID antenna is reduced, and the RFID antenna with ideal conductivity is manufactured.

Description

Technical Field

[0001] This application relates to the field of radio frequency identification technology, and in particular to a highly conductive RFID antenna, its fabrication process, and its applications. Background Technology

[0002] Ultra-high frequency radio frequency identification (UHF RFID) technology is widely used in many fields such as logistics, retail, and transportation due to its long reading and writing distance and strong multi-tag reading capability. As the core component of RFID tags, the conductivity of the RFID antenna directly determines the reading distance and reliability of the RFID tag.

[0003] Traditional RFID antenna fabrication often employs aluminum foil etching, but this process is complex and poses environmental pollution risks. Therefore, current methods typically involve fabricating antennas using graphene conductive ink via flexographic or gravure printing. However, the loosely packed and randomly oriented graphene sheets produced during printing result in excessively high sheet resistance, far exceeding the high conductivity requirements of RFID antennas. Summary of the Invention

[0004] To improve the conductivity of RFID antennas, this application provides a high-conductivity RFID antenna, its fabrication process, and its application.

[0005] Firstly, the fabrication process of a high-conductivity RFID antenna provided in this application adopts the following technical solution: A fabrication process for a high-conductivity RFID antenna includes the following steps: S1. The conductive ink is printed onto the substrate and dried in an oven that combines infrared and hot air to obtain an RFID antenna containing a conductive ink layer. S2. The RFID antenna containing the conductive ink layer is rolled to obtain a highly conductive RFID antenna; The conductive ink is a graphene conductive ink.

[0006] By adopting the above technical solution, graphene conductive ink is printed onto the substrate and dried in an oven using a combination of infrared and hot air. Infrared drying provides instantaneous and efficient penetrating heating, allowing the internal solvent of the graphene conductive ink to evaporate rapidly, initially forming a conductive network and improving the drying speed. Hot air drying provides uniform and gentle convective heating, further thoroughly removing residual solvent and promoting the bonding between the graphene conductive ink layer and the substrate, which helps to obtain a uniform and dense conductive ink layer. Then, through calendering, the contact between graphene sheets and between the sheets and the substrate is forced to be tighter, significantly reducing the contact resistance and porosity between graphene sheets, constructing a penetrating and efficient multidimensional conductive network, thereby reducing the sheet resistance of the RFID antenna and producing an RFID antenna with ideal conductivity.

[0007] This application first prints graphene conductive ink onto a substrate, and then promotes the formation of a uniform and dense conductive ink layer on the substrate through a combination of infrared drying and hot air drying. Then, through calendering, the graphene sheets slide and rotate mainly along the plane of the substrate and tend to be oriented parallel to the surface of the substrate. This significantly reduces the contact resistance and porosity between the graphene sheets, constructing a through-hole, efficient multi-dimensional conductive network, thereby reducing the sheet resistance of the RFID antenna and producing an RFID antenna with ideal conductivity.

[0008] Preferably, conductive ink is printed onto the substrate using a flexographic printing press, wherein the anilox roller of the flexographic printing press has a line count of 80-150 lines / inch, the dot ratio of the printing plate is 40-60%, and the printing speed is 50-100 m / min.

[0009] By adopting the above technical solution, when the line count of the anilox roller is between 80 and 150 lines per inch, the anilox roller can accurately transfer an appropriate amount of graphene ink to form a continuous, dense and moderately thick conductive pattern after drying and calendering. This ensures high conductivity while guaranteeing the pattern accuracy of the RFID antenna.

[0010] When the dot ratio of the printing plate is in the range of 40-60%, it can improve ink transfer and ink uniformity. Furthermore, the tiny gaps between the ink dots provide channels for infrared and hot air, allowing the volume of the graphene ink to evaporate more quickly and evenly from the ink layer, avoiding the problem of surface skinning while the inside remains undried. Simultaneously, after drying and subsequent calendering processes, these dense ink dots are flattened, fused, and densified to form an almost completely continuous conductive film, thereby improving the conductivity of the RFID antenna.

[0011] When the printing speed is between 50-100m / min, it can ensure the stability and high quality of the printed graphics, and can also match the "infrared + hot air" combined drying method to ensure that the graphene ink layer can be completely dried and cured under high-speed operation.

[0012] Preferably, the tension of the printing substrate is 30-50N.

[0013] By adopting the above technical solution, within this tension range, the substrate is moderately stretched, maintaining a flat, stable, and constant size as it passes through the printing unit, ensuring that the ink transferred by the anilox roller can be accurately printed to the preset position, forming a conductive pattern with highly accurate dimensions and excellent repeatability.

[0014] When the tension of the substrate is too low, the substrate is prone to local relaxation, wrinkling or lateral drift under multiple guide rollers and printing pressure, resulting in inaccurate registration of the printed pattern, distorted lines or inconsistent width. When the tension of the substrate is too high, the antenna pattern printed on the substrate will shrink or change in size after leaving the tension zone after being heated, causing the pattern size to deviate from the design value and affecting the performance of the RFID antenna.

[0015] Preferably, in S1, conductive ink is printed onto the substrate using a gravure printing machine. The cell depth of the gravure roller in the gravure printing machine is 15-40μm, the pressure of the doctor blade is 0.2-0.5MPa, the printing gap is 0.05-0.15mm, and the printing speed is 30-80m / min.

[0016] By adopting the above technical solution, when the cell depth of the gravure roller is 15-40μm, a wet ink layer of moderate thickness and uniformity can be accurately transferred and formed. This ensures that the wet ink layer can form a continuous, dense film with excellent conductivity after drying and calendering, while maintaining good edge sharpness of the pattern.

[0017] When the pressure of the doctor blade is in the range of 0.2-0.5MPa, it can achieve "clean and crisp" doctoring, ensuring that only the designed antenna pattern part is transferred with ink, and the edges of the pattern are clear and sharp.

[0018] When the printing gap is in the range of 0.05-0.15mm, it can provide a moderate and uniform printing force for the transfer of graphene conductive ink, ensuring that the graphene conductive ink in the cells can be fully and stably adsorbed on the surface of the substrate, and achieving high-precision, high-fidelity graphic transfer.

[0019] When the printing speed is between 30-80m / min, it can ensure good transfer and leveling of graphene conductive ink, forming a uniform ink layer, and also ensure that the graphene conductive ink layer is stable before entering the drying tunnel, making the subsequent drying and curing process controllable and efficient, thereby achieving an optimized balance between quality and production capacity.

[0020] Preferably, in S2, the linear pressure of calendering is 100-300 kN / m, and the calendering temperature is 20-80℃.

[0021] By adopting the above technical solution, when the linear pressure of calendering is between 100-300kN / m, it can effectively close the micropores and interlayer gaps formed during the drying process of graphene conductive ink. At the same time, it can force the graphene sheets to overcome van der Waals forces and slide and recombine, forming close face-to-face contact, which greatly reduces the contact resistance between graphene sheets.

[0022] When the calendering temperature is in the range of 20-80℃, the binder in the graphene conductive ink can transform from a glassy state to a highly elastic or viscous flow state, becoming more plastic and better wrapping and fixing the rearranged graphene sheets, filling microscopic defects. Furthermore, under these conditions, the kinetic energy of the graphene sheets can be increased, and the energy barrier for their mutual sliding can be reduced, enabling them to achieve effective rearrangement and tight stacking under relatively low pressure, thus achieving the effect of "soft pressing".

[0023] Preferably, in S2, the RFID antenna containing the conductive ink layer is calendered using a twin-roll heated calender. The diameter of the heated steel rolls in the twin-roll heated calender is 400-600 mm, and the gap between the rolls is 50-80% of the thickness of the conductive ink layer.

[0024] By adopting the above technical solution, when the diameter of the heated steel roller is between 400-600mm, it has strong compressive strength and can provide highly uniform linear pressure in the entire roll width direction, forming a sufficiently wide pressure zone. This allows the RFID antenna containing the conductive ink layer to have sufficient pressure residence time, ensuring the smoothness and fullness of the densification process. Furthermore, the large-diameter heated steel roller has a large heat capacity and small temperature fluctuation, which can provide a continuous and stable heat source for the calendering process.

[0025] When the gap between the rollers is 50-80% of the thickness of the conductive ink layer, the pores in the dried graphene conductive ink can be closed as much as possible, promoting the tight rearrangement of the graphene sheets while preserving the complete conductive pathway structure.

[0026] Preferably, the conductive ink also contains polyethyleneimine.

[0027] By adopting the above technical solution, polyethyleneimine is a high molecular polymer rich in amine groups. Its amine groups can generate strong electrostatic adsorption or form hydrogen bonds with the oxygen-containing functional groups on the surface of graphene sheets, thereby adsorbing onto the surface of graphene and promoting the stable dispersion of graphene in solvents. Under heating conditions, the amine groups in polyethyleneimine can form amide bonds with the carboxyl groups in graphene, firmly connecting polyethyleneimine and graphene by chemical bonds, which greatly enhances the adhesion between the conductive ink layer and the substrate.

[0028] Meanwhile, the amine groups on the polyacetylimide molecular chain are strong electron donors. When polyacetylimide is adsorbed onto the graphene surface, it injects its lone pair electrons into the graphene's π-bond system, introducing additional negative charge carriers into the graphene, achieving N-type chemical doping. This significantly increases the charge carrier concentration and Fermi level of the graphene itself, fundamentally reducing the sheet resistance of the graphene. Furthermore, when two graphene sheets modified with polyethyleneimine come into contact, the polyethyleneimine molecular layer acts as an "electron bridge," promoting electron transitions between different graphene sheets, thereby significantly reducing the contact resistance between the sheets.

[0029] Preferably, the amount of polyethyleneimine added accounts for 1-5% of the graphene mass.

[0030] By adopting the above technical solution, when the amount of polyacetylimide added is too low, the polyacetylimide cannot fully encapsulate the graphene, resulting in insignificant doping and dispersion improvement effects; when the amount of polyacetylimide added is too high, the excessive polyacetylimide will form an excessively thick insulating layer on the surface of the graphene sheet, hindering the direct tunneling and hopping transmission of electrons between graphene sheets, which will instead reduce conductivity. At the same time, excessive insulating polymers will destroy the integrity of the conductive network.

[0031] Secondly, this application provides a high-conductivity RFID antenna, which adopts the following technical solution: A high conductivity RFID antenna is manufactured using the same process as described above.

[0032] Thirdly, the application of the high-conductivity RFID antenna provided in this application adopts the following technical solution: An application of a high-conductivity RFID antenna, specifically its application in RFID tags or flexible electronic devices.

[0033] In summary, this application includes at least one of the following beneficial technical effects: 1. This application first prints graphene conductive ink onto a substrate, and then promotes the formation of a uniform and dense conductive ink layer on the substrate by combining infrared drying and hot air drying. Then, through calendering, the graphene sheets slide and rotate mainly along the plane of the substrate and tend to be oriented parallel to the surface of the substrate. This significantly reduces the contact resistance and porosity between the graphene sheets, constructs a penetrating and efficient multidimensional conductive network, thereby reducing the sheet resistance of the RFID antenna and producing an RFID antenna with ideal conductivity. 2. This application can use flexographic printing or gravure printing to print conductive ink onto the surface of the substrate, and combine it with precision calendering to improve the performance of conductive RFID antennas; 3. By adding polyethyleneimine to the conductive ink, this application not only promotes the dispersion of graphene, but also allows the amine groups in polyethyleneimine to form amide bonds with the carboxyl groups in graphene under heating conditions, thus firmly connecting polyethyleneimine and graphene through chemical bonds. This greatly enhances the adhesion between the conductive ink layer and the substrate. Furthermore, when polyacetylimine is adsorbed on the graphene surface, it injects its lone pair electrons into the π-bond system of graphene, achieving N-type chemical doping and fundamentally reducing the sheet resistance of graphene. Detailed Implementation

[0034] The raw materials in this application include the following: Graphene: 1-10μm graphene is used, and this application takes 5μm graphene as an example; Polyurethane: Waterborne polyurethane with CAS number 35430-88-7 is used; Polyacetylimide: A commercially available product with CAS number 25987-06-8 is used. This application takes a 50% aqueous solution of polyacetylimide with an average molecular weight of 800 as an example. Substrate: Paper, PET film, etc. can be used. This application takes paper as an example.

[0035] Preparation Example 1 The preparation method of graphene conductive ink includes the following steps: Step 1: Mix 10% graphene, 0.5% polyurethane and 89.5% solvent and disperse them evenly to obtain a mixture. The solvent is a mixture of water and ethanol with a volume ratio of 1:1. Step 2: Grind the mixture at 3000 rpm / min for 3 hours to obtain graphene conductive ink.

[0036] The present application will be further described in detail below with reference to embodiments and comparative examples. Example 1

[0037] A fabrication process for a high-conductivity RFID antenna includes the following steps: S1. Print graphene conductive ink to 60g / m using a flexographic printing press. 2 On the paper, the anilox roller in the flexographic printing press has a line count of 120 lines / inch, the dot ratio of the printing plate is 50%, the printing speed is 80m / min, and the paper tension is controlled at 40N and the doctor blade angle is 30°. The paper with the conductive ink layer is transported to an oven that combines infrared and 80°C hot air for drying. The oven is 2m long. After drying, an RFID antenna with a conductive ink layer is obtained. S2. The RFID antenna containing the conductive ink layer is transferred to a double-roll heated calender for calendering. The diameter of the heating steel rolls in the double-roll heated calender is 500mm, the gap between the rolls is 70% of the thickness of the conductive ink layer, the calendering temperature is 60℃, the linear pressure of calendering is 200kN / m, and the calendering speed is 30m / min, thus obtaining a high-conductivity RFID antenna. The calendering temperature is controlled by the temperature of the heating steel rolls.

[0038] Comparative Example 1 Comparative Example 1 is based on the preparation process of Example 1, except that S2 is removed and the other conditions remain unchanged, that is, a highly conductive RFID antenna is obtained through step S1.

[0039] Performance testing The highly conductive RFID antennas of Example 1 and Comparative Example 1 were analyzed, and the specific testing methods are as follows: 1. Average thickness After zeroing and calibrating the PostTector, the high-conductivity RFID antenna sample is fixed flat on a hard, horizontal surface, avoiding edges and defects. Ten representative measurement points (such as the start, middle, end, and bend of the line) are systematically selected. The probe is ensured to make vertical and stable contact with the conductive layer surface. The thickness value of each point is recorded. Finally, the arithmetic mean of all measurement points is calculated to obtain the average thickness of the antenna line.

[0040] 2. Average sheet resistance Nine representative measurement points are evenly selected on the RFID antenna pattern of the high conductivity RFID antenna sample, including the straight segments, bends, and the vicinity of the start and end points of the coil. The sample is then laid flat on a hard, flat, insulating platform. The sheet resistance value of the measurement points is detected and recorded using a four-probe sheet resistance tester (CRESBOX). The average sheet resistance is obtained by averaging the sheet resistance values ​​of all the measured test points.

[0041] 3. Adhesion The highly conductive RFID antenna sample was flattened and fixed. Using a 2mm cutting tool, 11 parallel scratches were made vertically and at a uniform speed in the conductive line area. The scratches should just completely penetrate the conductive ink layer and slightly touch but not deeply cut into the paper base. Then, the sample was rotated 90° and the cutting was repeated to form a 100-grid. A soft brush was then used to lightly sweep along the diagonal of the grid several times to firmly adhere the tape to the grid area. After standing for several minutes, the tape was quickly and smoothly peeled off in one go. The grid area was observed using a magnifying glass and evaluated against the standard grade chart: if the cut edges were smooth and no grid cells were missing, it was the best (grade 5); if the missing area was greater than 65%, it was the worst (grade 0).

[0042] 4. Line precision The clarity of the lines and edges of the high-conductivity RFID antenna sample was observed using an optical microscope.

[0043] Based on the above detection method, the test results of Example 1 and Comparative Example 1 were obtained, as shown in Table 1 below.

[0044] Table 1 Performance test results for Example 1 and Comparative Example 1

[0045] Referring to Table 1, it can be seen from the comparison between Example 1 and Comparative Example 1 that the performance of the high conductivity RFID antenna after calendering is significantly improved. This may be because during the calendering process, by applying controllable linear pressure and heat, the loosely stacked and randomly oriented graphene sheets after printing are forced to slide and rotate mainly along the plane of the substrate under shear force and heat, and tend to be oriented parallel to the surface of the substrate. This significantly reduces the contact resistance and porosity between the graphene sheets, thereby constructing a through-hole, efficient multidimensional conductive network, and achieving a significant reduction in the sheet resistance of the high conductivity RFID antenna.

[0046] Examples 2-5 Examples 2-5 are based on the preparation process of Example 1, but the parameters of the flexographic printing machine are adjusted, as shown in Table 2.

[0047] The high conductivity RFID antennas of Examples 2-5 were subjected to the above performance tests, and the test results are shown in Table 2.

[0048] Table 2. Parameters and performance test results of flexographic printing presses in Examples 1-5

[0049] Referring to Table 2, and comparing Examples 1-5, it can be seen that when the anilox roller of the flexographic printing press has a line count of 80-150 lines / inch, the dot ratio of the printing plate is 40-60%, and the printing speed is 50-100m / min, the resulting high conductivity RFID antenna has ideal graphic accuracy while ensuring high conductivity.

[0050] Examples 6-9 Examples 6-9 are based on the preparation process of Example 1, but the tension of the substrate is adjusted, as shown in Table 3.

[0051] The high conductivity RFID antennas of Examples 6-9 were subjected to the above performance tests, and the test results are shown in Table 3.

[0052] Table 3. Test results of substrate tension and performance in Examples 1 and 6-9

[0053] Referring to Table 3, a comparison of Examples 1 and 6-9 shows that the high-conductivity RFID antenna exhibits the best performance when the tension of the substrate is between 30-50N. This may be because when the tension of the substrate is too low, it is prone to localized relaxation, wrinkling, or lateral drift under multiple guide rollers and printing pressure, resulting in inaccurate registration of the printed pattern, distorted lines, or inconsistent width. When the tension of the substrate is too high, the antenna pattern printed on the substrate shrinks or changes in size after leaving the tension zone after being heated, causing the pattern size to deviate from the design value and affecting the performance of the RFID antenna.

[0054] Examples 10-14 Examples 10-13 are based on the preparation process of Example 1, with adjustments made to the linear pressure and calendering temperature in S2, as shown in Table 4.

[0055] Example 14 Example 14 is based on the preparation process of Example 1, but the rolling temperature is adjusted, that is, the heating steel roller is not heated, while the other conditions remain unchanged.

[0056] The high conductivity RFID antennas of Examples 10-14 were subjected to the above performance tests, and the test results are shown in Table 4.

[0057] Table 4. Calendering conditions and performance testing results for Examples 1 and 10-14

[0058] Referring to Table 4, a comparison of Examples 1 and 10-13 shows that the high conductivity RFID antenna exhibits the best performance when the linear pressure of calendering is in the range of 100-300 kN / m and the calendering temperature is in the range of 20-80°C. This is because the micropores and interlayer gaps in the graphene conductive ink can be effectively closed at this temperature, forcing the graphene sheets to achieve effective rearrangement and tight stacking under relatively low pressure.

[0059] Comparing Example 1 and Example 14, it can be seen that rolling the RFID antenna containing the conductive ink layer without heating can also effectively improve the performance of the high conductivity RFID antenna.

[0060] Examples 15-18 Examples 15-18 are based on the preparation method of Example 1, with the parameters of the twin-roll heated calender adjusted as shown in Table 5.

[0061] The high conductivity RFID antennas of Examples 15-18 were subjected to the above performance tests, and the test results are shown in Table 5.

[0062] Table 5. Parameters and performance test results of the twin-roll heated calenders in Examples 1 and 15-18.

[0063] Referring to Table 5, a comparison of Example 1 and Examples 15-18 shows that when the diameter of the heating steel roller is 400-600 mm and the gap between the rollers accounts for 50-80% of the thickness of the conductive ink layer, the resulting high conductivity RFID antenna has ideal performance.

[0064] Example 19 Example 19: Based on the preparation process of Example 1, polyethyleneimine was added to the conductive ink. The amount of polyethyleneimine added was 3% of the mass of graphene, and the other conditions remained unchanged.

[0065] Examples 20-23 Examples 20-23 are based on the preparation process of Example 19, but the amount of polyethyleneimine added is adjusted, as shown in Table 6.

[0066] The high conductivity RFID antennas of Examples 19-23 were subjected to the above performance tests, and the test results are shown in Table 6.

[0067] Table 6. Polyethyleneimine Addition Amount and Performance Test Results for Examples 1 and 19-23

[0068] Referring to Table 6, a comparison of Examples 1 and 19 shows that the addition of polyethyleneimine significantly improves the performance of the high-conductivity RFID antenna. This is likely because the amino groups of polyethyleneimine can generate strong electrostatic adsorption or form hydrogen bonds with the oxygen-containing functional groups on the surface of graphene sheets, thereby adsorbing onto the graphene surface and promoting the stable dispersion of graphene in the solvent. Under heating, the amino groups in polyethyleneimine can form amide bonds with the carboxyl groups in graphene, firmly connecting polyethyleneimine and graphene through chemical bonds, greatly enhancing the adhesion between the conductive ink layer and the substrate. Simultaneously, when polyethyleneimine is adsorbed onto the graphene surface, the amino groups can inject their lone pair electrons into the π-bond system of graphene, achieving N-type chemical doping and reducing the sheet resistance of graphene.

[0069] Comparative examples 19-23 show that the conductive RFID antenna exhibits the best performance when the amount of polyacetylimide added accounts for 1-5% of the graphene mass. This may be because when the amount of polyacetylimide added is too low, it cannot fully encapsulate the graphene, resulting in insignificant doping and dispersion improvement effects. When the amount of polyacetylimide added is too high, excessive polyacetylimide will form an excessively thick insulating layer on the graphene sheet surface, hindering the direct tunneling and hopping transmission of electrons between graphene sheets, which will reduce conductivity. At the same time, excessive insulating polymers will damage the integrity of the conductive network.

[0070] Example 24 A fabrication process for a high-conductivity RFID antenna includes the following steps: S1. Print graphene conductive ink to 60g / m using a gravure printing machine. 2 On the paper, the cell depth of the gravure roller in the gravure printing machine is 30μm, the pressure of the doctor blade is 0.35MPa, the printing gap is 0.12mm, and the printing speed is 60m / min. Then the paper with the conductive ink layer is transported to the drying tunnel that combines infrared and 80℃ hot air for drying. The length of the drying tunnel is 2m. After drying, an RFID antenna with a conductive ink layer is obtained. S2. The RFID antenna containing the conductive ink layer is transferred to a double-roll heated calender for calendering. The diameter of the heated steel roll in the double-roll heated calender is 500 mm, the gap between the rolls is 70% of the thickness of the conductive ink layer, and the temperature of the heated steel roll is set to 60℃. The linear pressure of calendering is 200 kN / m, and the calendering speed is 30 m / min, thus obtaining a high-conductivity RFID antenna.

[0071] Comparative Example 2 Comparative Example 2 is based on the preparation process of Example 24, except that S2 is removed and the other conditions remain unchanged, that is, a highly conductive RFID antenna is obtained through step S1.

[0072] The high conductivity RFID antennas of Example 24 and Comparative Example 2 were subjected to the above performance tests, and the test results are shown in Table 7.

[0073] Table 7 Performance test results for Examples 1, 24 and Comparative Example 2

[0074] Referring to Table 7, it can be seen from the comparison of Example 1, Example 24 and Comparative Example 2 that the performance of high conductivity RFID antennas can be significantly improved by combining flexographic printing or gravure printing with precision calendering.

[0075] Examples 25-28 Examples 25-28 are based on the preparation process of Example 24, with adjustments made to the parameters of the gravure printing machine, as shown in Table 8.

[0076] The high conductivity RFID antennas of Examples 25-28 were subjected to the above performance tests, and the test results are shown in Table 8.

[0077] Table 8. Gravure printing machine parameters and performance test results for Examples 24-28

[0078] Referring to Table 8, and comparing Examples 24-28, it can be seen that when the cell depth of the gravure roller in the gravure printing machine is 15-40μm, the doctor blade pressure is 0.2-0.5MPa, the printing gap is 0.05-0.15mm, and the printing speed is 30-80m / min, the performance of the obtained high conductivity RFID antenna is optimal.

[0079] All of the above embodiments 1-28 can be put into practical use. The following application examples are illustrated by embodiments 1 and 24.

[0080] Application Example 1 The highly conductive RFID antenna obtained in Example 1 was coupled into the Alien Higgs-4 chip to form an RFID tag.

[0081] Application Example 2 The highly conductive RFID antenna obtained in Example 24 was coupled into the Alien Higgs-4 chip to form an RFID tag.

[0082] Comparative Example 3 The highly conductive RFID antenna obtained in Comparative Example 1 was coupled into the Alien Higgs-4 chip to create an RFID tag.

[0083] Comparative Example 4 The highly conductive RFID antenna obtained in Comparative Example 2 was coupled into the Alien Higgs-4 chip to create an RFID tag.

[0084] The RFID tags of Application Examples 1-2 and Comparative Examples 3-4 were tested for read and write distance in a non-reflective test environment conforming to the EPCglobal Class-1 Gen-2 standard in the 920MHz UHF band.

[0085] Table 9 Performance Test Table for Application Examples 1-2 and Comparative Examples 3-4

[0086] Referring to Table 9, a comparison of Application Examples 1-2 and Comparative Examples 3-4 shows that the performance of the high-conductivity RFID antenna after flexographic / gravure printing and calendering is significantly better than that of the high-conductivity RFID antenna without calendering.

[0087] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A fabrication process for a high-conductivity RFID antenna, characterized in that, Includes the following steps: S1. The conductive ink is printed onto the substrate and dried in an oven that combines infrared and hot air to obtain an RFID antenna containing a conductive ink layer. S2. The RFID antenna containing the conductive ink layer is rolled to obtain a highly conductive RFID antenna; The conductive ink is a graphene conductive ink.

2. The fabrication process of a high-conductivity RFID antenna according to claim 1, characterized in that, In S1, conductive ink is printed onto the substrate using a flexographic printing press. The flexographic printing press has an anilox roller with a line count of 80-150 lines per inch, a dot ratio of 40-60% for the printing plate, and a printing speed of 50-100 m / min.

3. The fabrication process of a high-conductivity RFID antenna according to claim 2, characterized in that, The tension of the printing substrate is 30-50N.

4. The fabrication process of a high-conductivity RFID antenna according to claim 1, characterized in that, In S1, conductive ink is printed onto the substrate using a gravure printing machine. The cell depth of the gravure roller in the gravure printing machine is 15-40μm, the pressure of the doctor blade is 0.2-0.5MPa, the printing gap is 0.05-0.15mm, and the printing speed is 30-80m / min.

5. The fabrication process of a high-conductivity RFID antenna according to claim 1, characterized in that, In S2, the linear pressure of calendering is 100-300 kN / m, and the calendering temperature is 20-80℃.

6. The fabrication process of a high-conductivity RFID antenna according to claim 5, characterized in that, In S2, the RFID antenna containing the conductive ink layer is calendered using a twin-roll heated calender. The diameter of the heated steel rolls in the twin-roll heated calender is 400-600 mm, and the gap between the rolls is 50-80% of the thickness of the conductive ink layer.

7. The fabrication process of a high-conductivity RFID antenna according to claim 1, characterized in that, The conductive ink also contains polyethyleneimine.

8. The fabrication process of a high-conductivity RFID antenna according to claim 7, characterized in that, The amount of polyethyleneimine added is 1-5% of the graphene mass.

9. A high-conductivity RFID antenna, characterized in that, It is manufactured using the fabrication process of a high conductivity RFID antenna as described in any one of claims 1-8.

10. An application of a high-conductivity RFID antenna, characterized in that, The application of the high conductivity RFID antenna as described in claim 9 in RFID tags or flexible electronic devices.

Images