Flexible degradable radio frequency tag manufacturing method and radio frequency tag

Abstract

The invention provides a manufacturing method of a flexible and degradable radio frequency tag and the radio frequency tag, and belongs to the technical field of radio frequency identification (RFID). The method comprises the following steps: providing a substrate which is a degradable flexible composite material prepared from lactic acid and nano cellulose; a through groove is carved in the substrate through the ultraviolet laser technology, and a pre-designed antenna pattern is formed; the groove of the antenna pattern is filled with silver-graphene mixed conductive ink prepared in advance through the micro intaglio printing technology, sintering and curing are conducted at the temperature of 120-180 DEG C, and an antenna is formed; transversely cutting the substrate from the thickness direction of the substrate to obtain multiple layers of sub-substrates; and covering the two surfaces of the sub-substrate with a degradable covering film, and flip-mounting the chip. According to the method, the degradable flexible composite material is adopted as the substrate, the groove is carved, the groove is filled with the silver-graphene mixed conductive ink prepared in advance, the substrate is degradable and environmentally friendly, the metal layer can be recycled, and the metal material can be saved through the filling technology.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of radio frequency identification (RFID) technology, and in particular to a method for manufacturing a flexible and degradable radio frequency tag and the radio frequency tag. Background Art

[0002] In RFID tags, the antenna is an electronic circuit designed to meet the functional requirements of RFID. Antenna quality is a key issue that must be controlled during RFID tag manufacturing. The most common methods are etching and printing. Etching involves coating the substrate with copper or aluminum foil, applying photoresist, exposing and developing the material, chemically etching, and then cleaning and drying. Its advantages include high precision and low cost, making it suitable for high-frequency (HF) and ultra-high-frequency (UHF) tags. Printing involves directly printing the antenna using conductive ink (such as silver paste) via screen printing or inkjet printing.

[0003] Features: low cost, suitable for mass production, but conductivity is slightly inferior to metal antennas.

[0004] However, the traditional etching and printing methods have the following problems:

[0005] 1. The conductive ink printing process has low cost, but high resistivity, which affects the sensitivity of the label.

[0006] 2. The circuit etching accuracy is high, but the equipment cost is high and it is difficult to apply on a large scale.

[0007] 3. Flexible substrate: PI substrate cannot be degraded in nature and cannot meet the increasing environmental protection needs. Summary of the Invention

[0008] The purpose of the embodiments of the present disclosure is to provide a method for manufacturing a flexible and degradable radio frequency tag and a tag, thereby solving the aforementioned problems existing in the prior art.

[0009] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present disclosure are as follows:

[0010] In one aspect, an embodiment of the present disclosure provides a method for manufacturing a flexible and degradable radio frequency tag, the method comprising:

[0011] Providing a substrate, wherein the substrate is a degradable flexible composite material prepared from lactic acid and nanocellulose;

[0012] Carving through grooves on the first surface of the substrate by ultraviolet laser technology to form a pre-designed antenna pattern;

[0013] The pre-prepared silver-graphene hybrid conductive ink is filled into the groove of the antenna pattern using micro-gravure printing technology, and then sintered and cured at 120°C to 180°C to form the antenna;

[0014] cutting the substrate transversely in the thickness direction of the substrate to obtain a multi-layer sub-substrate;

[0015] Covering the first surface of the sub-base with a degradable film, reserving a chip position, and flip-mounting the RFID chip to the antenna at the reserved position;

[0016] Flip the sub-base, cover the second surface with a degradable film, reserve a chip position, and flip-mount the RFID chip to the antenna at the reserved position.

[0017] Optionally, the thickness of the substrate is 1 cm to 2 cm; the depth of the sub-substrate groove ranges from 5 μm to 50 μm; and the distance between two adjacent grooves is not less than 40 μm.

[0018] Optionally, the step of transversely cutting the substrate in a thickness direction of the substrate to obtain a multi-layer sub-substrate comprises:

[0019] Determine the cutting process based on the value parameters of the label application scenario.

[0020] Optionally, determining the cutting process according to the value parameters of the label application scenario includes:

[0021] When the label value parameter is ≥￥5 / piece, the substrate is cut using a diamond wire saw in combination with a -30℃ to -20℃ low-temperature freezing bonding process;

[0022] When the label value parameter is less than ￥2 / piece, the substrate is cut using a step-by-step composite process of water jet rough cutting and vibration knife fine cutting.

[0023] Optionally, flip-chipping the RFID chip on the antenna of the sub-base includes:

[0024] The RFID chip is flip-chip mounted on the antenna through a hot-press bonding process using anisotropic conductive adhesive (ACF) and connected to the corresponding pads of the antenna. The vertical pressure applied to the chip ranges from 18 kg to 22 kg, the target temperature range of the hot press plate or hot press head ranges from 150°C to 200°C, and the hot press time ranges from 2 seconds to 5 seconds.

[0025] Optionally, the method of preparing a degradable flexible composite material substrate using lactic acid and nanocellulose includes:

[0026] Solution blending-casting film method:

[0027] Dissolve the PLA particles in chloroform or dichloromethane at 50°C to 70°C and stir until completely dissolved, wherein the concentration of chloroform or dichloromethane is in the range of 5% w / v to 10% w / v;

[0028] Ultrasonic dispersion of the modified NFC in the PLA solution, wherein the concentration of the modified NFC is in the range of 1 wt% to 20 wt% and the ultrasonic dispersion is carried out for 20 min to 40 min;

[0029] The mixed solution is poured onto a glass plate and coated to form a film. After the solvent is evaporated at room temperature, vacuum drying is performed at 50°C to 70°C to obtain a flexible composite material substrate.

[0030] or,

[0031] Melt blending-extrusion / filming method:

[0032] PLA and NFC are vacuum dried at 60℃~100℃ for 12 hours or more;

[0033] A twin-screw extruder is used to extrude the mixture, wherein the NFC addition amount is 5wt% to 15wt%, the internal temperature of the twin-screw extruder is 170°C to 190°C, and the rotation speed is 50rpm to 100rpm;

[0034] Or use internal mixer and mix at 180℃ for 10 minutes;

[0035] The mixture is formed into a film with a thickness ranging from 50 μm to 200 μm by a hot press; wherein the hot pressing temperature of the hot press is 160° C. to 190° C., the pressure is 8.5 MPa to 11 MPa, and the hot pressing time is 4 minutes to 6 minutes;

[0036] injection molding into a flexible composite substrate;

[0037] or,

[0038] Preparation of flexible fiber membranes, i.e. flexible composite material substrates, by electrospinning:

[0039] A PLA / NFC mixed solution was prepared, wherein the concentration of PLA was 8% w / v, the concentration of NFC was 1 wt% to 5 wt%, and the solvent was chloroform / DMF = 7:3;

[0040] The electrospinning parameters were voltage 15-20 kV, receiving distance 15 cm, and flow rate 1 mL / h.

[0041] Optionally, each sub-substrate has multiple antenna arrays, and before the through grooves are engraved on the substrate, the method further includes:

[0042] Coarse positioning marks are respectively provided at the four corners of the first surface of the sub-base, and fine positioning marks are provided around each preset number of antenna units to be grooved;

[0043] After the first surface of the sub-base is covered with a degradable film and the chip is flipped, each sub-base forms a plurality of label arrays, and L-shaped corner marks are set at the four corners of each label unit.

[0044] Optionally, the step of engraving a through groove on the substrate by using ultraviolet laser technology includes:

[0045] According to the geometric characteristics of the antenna pattern, the scanning groove mode is pre-set and the laser parameters are adjusted synchronously;

[0046] Divide the antenna pattern into straight line area, acute angle area, arc area and cross point area;

[0047] According to the coarse positioning mark and the fine positioning mark, the laser is positioned to the substrate to be grooved and the antenna unit to be grooved respectively;

[0048] Determine the area of ​​the section to be grooved. If the section to be grooved is a straight line area, use full power, maximum speed, full parameters, and 15% overlap rate to groove.

[0049] If the groove section to be cut is an acute angle area, horizontal / vertical groove separation is adopted, and the power is linearly reduced to half power groove; overlap 8um;

[0050] If the groove section to be engraved belongs to the arc area, the arc checking and continuous scanning is adopted, the speed is reduced to 60% of the maximum speed, and the pulse frequency is increased to 80kHz;

[0051] If the section to be grooved belongs to the cross-intersection area, layered scanning is adopted, with the first layer grooved to 50% depth, and the second layer refined to complete the full depth of the groove.

[0052] Optionally, a plurality of label arrays with a spacing greater than 2 mm are formed on each sub-base;

[0053] After the first surface of each sub-base is turned over, a film is attached to the first surface of each sub-base;

[0054] After flip-chipping the second surface of each sub-base, cutting each label along the gap between each label;

[0055] The adhesive film on the first surface of each sub-base is removed.

[0056] Optionally, the material of the degradable coating is polybutylene succinate (PBS) and its copolymer PBAT, with a thickness of 25 μm to 50 μm.

[0057] Another aspect of the present disclosure provides a radio frequency tag manufactured using the flexible and degradable radio frequency tag manufacturing method described above.

[0058] The beneficial effects of the embodiments of the present disclosure are:

[0059] The disclosed embodiment uses a degradable flexible composite material as a substrate, utilizes ultraviolet laser technology to carve grooves, and uses pre-prepared silver-graphene hybrid conductive ink to fill the grooves. The substrate is degradable and environmentally friendly, the metal layer is recyclable, and the filling process can save metal materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a flow chart of a method for manufacturing a flexible and degradable radio frequency tag according to an embodiment of the present disclosure;

[0061] Figure 2 This is a schematic diagram of the antenna pattern array structure formed after notching during the manufacturing process of a flexible and degradable radio frequency tag proposed in an embodiment of the present disclosure;

[0062] Figure 3 A schematic diagram of a substrate structure for manufacturing a flexible and degradable radio frequency tag proposed in an embodiment of the present disclosure;

[0063] Figure 4 This is a schematic structural diagram of a substrate after grooves are engraved during the manufacturing process of a flexible and degradable radio frequency tag proposed in an embodiment of the present disclosure;

[0064] Figure 5 This is a schematic structural diagram of a flexible and degradable radio frequency tag after a groove is filled with silver-graphene mixed conductive ink during the manufacturing process of the embodiment of the present disclosure;

[0065] Figure 6 This is a schematic structural diagram of a substrate cut transversely during the production process of a flexible and degradable radio frequency tag proposed in an embodiment of the present disclosure;

[0066] Figure 7 This is a schematic structural diagram of a flexible and degradable radio frequency tag after laminating the first surface of the sub-base during the manufacturing process of the embodiment of the present disclosure;

[0067] Figure 8 This is a structural diagram of a flexible and degradable radio frequency tag manufacturing process proposed in an embodiment of the present disclosure, wherein the first surface of the sub-base is coated and the chip is flip-chip mounted;

[0068] Figure 9 This is a structural diagram of a flexible and degradable radio frequency tag after flip-chip lamination on the second surface of a sub-base during the manufacturing process of the embodiment of the present disclosure;

[0069] Figure 10 This is a schematic structural diagram of each tag array of a cutting sub-base during the manufacturing process of a flexible and degradable radio frequency tag proposed in an embodiment of the present disclosure;

[0070] Figure 11 The figure is a schematic structural diagram of a label obtained by using a method for manufacturing a flexible and degradable radio frequency label proposed in an embodiment of the present disclosure.

[0071] In the figure,

[0072] 100, substrate; 110, coarse positioning mark; 120, fine positioning mark; 130, sub-substrate; 200, groove; 300, silver-graphene hybrid conductive ink; 400, ACF; 500, chip; 600, degradable film; 700, adhesive film. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the embodiments of the present disclosure are further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the embodiments of the present disclosure and are not intended to limit the embodiments of the present disclosure.

[0074] like Figure 1 As shown, the embodiment of the present disclosure provides a method for manufacturing a flexible and degradable radio frequency tag, the method comprising:

[0075] Step S100: providing a substrate, wherein the substrate is a degradable flexible composite material prepared from lactic acid and nanocellulose.

[0076] like Figure 3 As shown, the substrate 100 in the embodiment of the present disclosure adopts a pre-prepared degradable flexible composite material. The substrate of the embodiment of the present disclosure can be prepared by solution blending-casting film method, melt blending-extrusion / pressing film method or electrospinning method, and the natural degradation rate of the substrate within 180 days is ≥90%.

[0077] Specifically, the method of preparing a degradable flexible composite material substrate using lactic acid and nanocellulose includes:

[0078] Solution blending-casting film method:

[0079] Dissolving polylactic acid (PLA): Dissolve PLA pellets in chloroform or dichloromethane at a concentration of 5% w / v to 10% w / v, and stir at 50°C to 70°C until completely dissolved, preferably 60°C.

[0080] Dispersing nanocellulose NFC: ultrasonically dispersing the modified NFC in a PLA solution; the modified NFC concentration range is 1 wt% to 20 wt%, and the ultrasonic dispersion time is 20 min to 40 min, preferably 30 min, with an ultrasonic dispersion power of 200 W; that is, the ultrasonic equipment outputs 200 joules of energy per second to break up NFC agglomerates.

[0081] Film casting: pour the mixed solution onto a glass plate, apply it by scraping to form a film, evaporate the solvent at room temperature, and then vacuum dry it at 50°C to 70°C; preferably, the drying temperature is 60°C.

[0082] The advantage of solution blending-casting film forming method is uniform dispersion. Alternatively,

[0083] Melt blending-extrusion / filming method:

[0084] Drying raw materials: PLA and NFC are vacuum dried at 60℃~100℃, preferably 80℃, for 12 hours or more;

[0085] Melt blending:

[0086] The mixed material is extruded using a twin-screw extruder. The internal temperature of the twin-screw extruder is 170° C. to 190° C., the rotation speed is 50 rpm to 100 rpm, the amount of the base material PLA is 85 wt% to 95 wt%, and the amount of NFC added is 5 wt% to 15 wt%;

[0087] Or use internal mixer: mix at 180℃ for 8-15min, preferably 10min;

[0088] forming:

[0089] Lamination: The mixture is formed into a film with a thickness of 50 μm to 200 μm using a hot press. The parameters of the hot press are as follows: a hot pressing target temperature of 160° C. to 190° C., preferably 180° C., a pressure of 8.5 MPa to 11 MPa, preferably 10 MPa, and a hot pressing time of 4 minutes to 6 minutes, preferably 5 minutes;

[0090] Injection molding: Injection molding into flexible composite substrates;

[0091] Advantages of melt blending-extrusion / film pressing method: suitable for industrial production and no solvent residue.

[0092] Preparation of flexible fiber membranes, i.e. flexible composite material substrates, by electrospinning:

[0093] A PLA / NFC mixed solution was prepared, wherein the concentration of PLA was 8% w / v, the concentration of NFC was 1 wt% to 5 wt%, and the solvent was chloroform / N-dimethylformamide (DMF) = 7:3;

[0094] Electrospinning parameters: voltage 15 kV–20 kV, receiving distance 15 cm, flow rate 1 mL / h.

[0095] The voltage of 15kV to 20kV is the electric field strength between the solution injection device and the collecting plate; the receiving distance of 15cm is the injection distance, which refers to the distance from the nozzle to the receiving device (such as aluminum foil or rotating drum); the flow rate refers to the speed at which the feed pump pushes the polymer solution to the nozzle.

[0096] Before grooving, a film is applied to the second surface of the substrate to prevent the substrate from falling apart after grooving. The substrate is fixed to a workbench with grid lines, and the intersections of the grid lines can be marked with horizontal and vertical coordinates. The first surface of the substrate faces upward, and coarse positioning marks 110 are respectively set at the four corners of the first surface of the substrate. The coordinates or grid positions of the coarse positioning marks are recorded to facilitate rapid positioning of the substrate by infrared laser. Fine positioning marks 120 are set around each preset number of antenna units to be grooved. The fine positioning marks can be micro triangle marks △.

[0097] The coarse positioning mark can be a concentric double circle ◎ or a cross +. The coarse positioning mark is used to identify the position of the substrate, and the fine positioning mark is used to identify the position of the antenna unit to be grooved.

[0098] The efficiency and accuracy of UV laser grooving can be improved by setting coarse and fine positioning marks.

[0099] Step S200: Forming a pre-designed antenna pattern array by engraving through grooves on the substrate using ultraviolet laser technology.

[0100] In step S200 of the embodiment of the present disclosure, a through groove 200 is engraved on the substrate from the first surface to the second surface using laser technology according to a pre-designed antenna pattern. A plurality of antenna pattern arrays can be designed in advance on the substrate, and through grooves are engraved on the substrate according to the pre-designed engraving path to form an antenna pattern array, such as Figure 2 As shown, the substrate position and the position of the antenna unit to be grooved are identified by the coarse positioning mark and the fine positioning mark; the antenna is formed after the groove is carved, as shown in FIG. Figure 4 Laser grooving ensures circuit precision and eliminates the need for etching, making it more environmentally friendly.

[0101] In the disclosed embodiment, the substrate thickness is 1 cm to 2 cm; the overall groove thickness is also 1 cm to 2 cm; and the groove width is 0.05 mm to 1 mm. The spacing between adjacent grooves is no less than 40 μm, and preferably, the groove spacing is 50 μm. There is no upper limit for controlling the groove spacing; the lower limit is controlled to avoid short circuits.

[0102] Exemplarily, the step of engraving a through groove on the substrate by ultraviolet laser technology includes:

[0103] Step S210 : Preset and switch the scanning groove mode according to the geometric characteristics of the antenna pattern and adjust the laser parameters synchronously to achieve a high-speed straight line and precise corner processing strategy.

[0104] Step S220: Divide the antenna pattern into a straight line area, an acute angle area, an arc area, and a cross-intersection area.

[0105] In step S220, the antenna pattern can be divided into straight line regions, acute angle regions, arc regions, and cross-intersection regions based on curvature and angle. The cross-intersection region is relatively rare. Specifically, a straight line region is defined when the curvature κ is less than 0.01, the steering angle is less than 5°, and three consecutive points are nearly collinear. A curved region is defined when the curvature κ is 0.01 ≤ and the curvature κ is less than 0.3, and the steering angle is 5° ≤ and the curvature is less than 90°, with smooth curvature without sudden changes. A sharp angle region is defined when the curvature κ is greater than or equal to 0.3, the steering angle is greater than or equal to 90°, and there is a significant directional change. A cross-intersection region is defined when the curvature is N / A, multiple line segments intersect, and the angle between adjacent line segments is approximately 90°±5°.

[0106] Step S230 : Positioning the laser on the substrate to be grooved and the antenna unit to be grooved according to the coarse positioning mark and the fine positioning mark.

[0107] Step S240 , determining the area of ​​the segment to be grooved. If the segment to be grooved is a straight line area, grooves are cut using full power 8W, maximum speed 400 mm / s, and 15% overlap.

[0108] If the groove section to be cut is in an acute angle area, horizontal / vertical groove separation is adopted, the power is linearly reduced to half power 4W groove cutting, and the overlap is 8um. The acute angle is less than 90°.

[0109] If the groove segment to be engraved is an arc, arc scanning is used, with the speed reduced to 60% of the maximum speed, which can be 250mm / s, and the pulse frequency increased to 80kHz. The arc, 90° to 180°, represents a certain arc on the circumference. The corresponding central angle of this arc ranges from 90 degrees to 180 degrees.

[0110] If the section to be grooved belongs to the cross-intersection area, layered scanning is adopted, with the first layer grooved to 50% depth, and the second layer refined to complete the full depth of the groove.

[0111] Grooves were made on the polylactic acid / nanocellulose biodegradable flexible material using UV laser technology.

[0112] Step S300: Using micro-gravure printing technology to fill the pre-prepared silver-graphene hybrid conductive ink into the grooves of the antenna pattern, and sintering and curing at 120° C. to 180° C. to form an antenna array.

[0113] In the embodiment of the present disclosure, the silver-graphene hybrid conductive ink 300 is filled into the micro groove by micro gravure printing. Figure 5 As shown, after sintering and curing at 150°C, a continuous conductive line with a thickness of 1cm to 2cm is formed, forming an antenna. Specifically, a scraper is used to scrape off the silver-graphene hybrid conductive ink on the surface, and the grooves are filled with graphene.

[0114] The micro-groove filling process in step S300 saves 25% to 35% of metal material usage, thereby reducing costs.

[0115] The components of silver-graphene hybrid conductive ink include: silver powder 70wt%~80wt%, providing the main conductive path, and the volume resistivity is 1.59×10 －8 Ω·m; 5wt% to 10wt% graphene, which enhances the conductive network, has an in-plane conductivity greater than 10□S / m, and inhibits silver migration; 15wt% to 20wt% binder, which can be epoxy resin or polyurethane, with a curing temperature less than 120°C, and a balance between adhesion and flexibility; a solvent, an appropriate amount of terpineol / ethylene glycol, with a boiling point greater than 200°C, and a viscosity adjusted to 2000cP to 5000cP; and 0.5wt% to 1wt% polyvinylpyrrolidone (PVP) or BYK-190, which is a dispersant, to prevent silver powder / graphene agglomeration.

[0116] The preparation process of silver-graphene hybrid conductive ink is as follows:

[0117] Step S310: pre-treating the graphene to obtain a solution containing graphene.

[0118] Specifically, in step S311, graphene oxide (GO) is hydrothermally reduced with ascorbic acid at 80° C. for 2 hours to obtain conductive graphene rGO. The mass ratio of graphene oxide to ascorbic acid is 1:5.

[0119] Step S312: centrifugation and washing to remove reaction by-products, and vacuum drying to obtain rGO powder.

[0120] Step S320: Mix the silver powder and the graphene to obtain a mixture.

[0121] Specifically, in step S321, silver powder with a particle size of 1 μm to 3 μm and rGO are added into a planetary ball mill in proportion, and zirconium oxide balls are added, and the mixture is milled in the planetary ball mill at a rotation speed of 300 rpm for 2 hours.

[0122] Step S322: adding 0.5 wt% PVP to prevent reagglomeration.

[0123] Step S323: Ultrasonic-assisted dispersion:

[0124] Step S324 , adding a solvent of terpineol and ethylene glycol to the mixed powder, with the ratio of terpineol to ethylene glycol being 7:3, and ultrasonically treating for 1 hour with an ultrasonic frequency parameter of 40 kHz.

[0125] Step S330: prepare an adhesive.

[0126] Specifically, in step S331, epoxy resin and curing agent are mixed at a ratio of 10:1 and dissolved in a solvent, wherein the solvent accounts for 5 wt% to 10 wt% of the total system. The epoxy resin may be E-44, and the curing agent may be polyetheramine D230.

[0127] Step S332: adding 0.2 wt% of defoaming agent, which may be BYK-066N.

[0128] Step S340: mixing and homogenizing the ink.

[0129] Specifically, in step S341, the silver-graphene composite slurry is mixed with the binder solution, and high-speed shearing is performed at 10,000 rpm for 30 minutes in a high-shear disperser.

[0130] Step S342: The slurry after high-speed shearing is put into a three-roll mill and ground with a gap of 10 μm, and the grinding is repeated for three times until the particle size D50 is less than 1 μm. The gap of 10 μm refers to the minimum distance between the rollers.

[0131] Step S343: adjust the viscosity to 3000±500 cP with terpineol, and control the temperature at 25°C.

[0132] Step S400: cutting the substrate transversely along the thickness direction of the substrate to obtain a multi-layer sub-substrate.

[0133] like Figure 6 As shown, the substrate is cut transversely to form a multilayer sub-substrate 130. The thickness of the sub-substrate ranges from 5µm to 50µm. The thinner the groove depth, the thinner the circuitry and the thinner the substrate, which translates to a lighter and thinner label. Specifically, considering the cutting cost and the varying value of label application scenarios, the cutting process is determined based on the value parameters of the label application scenario.

[0134] In the embodiment of the present disclosure, the value parameter of the label is cost. The method of determining the cutting process according to the value parameter of the label application scenario includes:

[0135] Step S410: When the label value parameter is ≥￥5 / piece, the substrate is cut using a diamond wire saw in combination with a -30°C to -20°C low-temperature freeze bonding process.

[0136] First, a 2cm substrate is frozen to -25°C and hardened to an "acrylic sheet"-like state. In the diamond wire saw process, the wire diameter is 0.05-0.1mm, the cutting tension is 15-25N, and it is temporarily bonded to the silicon carrier plate with UV strippable adhesive.

[0137] Step S420: When the label value parameter is less than ￥2 / piece, the substrate is cut using a step-by-step composite process of water jet rough cutting and vibrating knife fine cutting.

[0138] The step-by-step composite process is specifically as follows:

[0139] a) using a high-pressure pure water jet at a pressure of 300-400 MPa to cut the substrate into modules with a thickness of 3-5 mm;

[0140] b) Using a vibrating knife with a frequency of 20 to 40 kHz, the module is cut into 50 to 100 μm slices under cold air cooling.

[0141] When the unit price of the label is between ￥2 and ￥5 per piece, that is, when the unit price of the label is greater than or equal to ￥2 per piece and less than ￥5 per piece, the diamond wire saw process or the step-by-step cutting process can be selected according to the actual precision requirements.

[0142] Step S500: Cover the first surface of the sub-base with a degradable film to reserve a chip position, and flip-mount the RFID chip to the antenna at the reserved position.

[0143] like Figure 7 and Figure 8 As shown, the RFID chip is first laminated and then attached to the antenna pad. The material of the degradable coating can be polybutylene succinate (PBS) and its copolymer (PBAT).

[0144] In step S500 of the embodiment of the present disclosure, anisotropic conductive adhesive ACF400 is used to flip-chip the RFID chip 500 onto the antenna through a pressure-heat bonding process, and connected to the corresponding pads of the antenna; wherein, the vertical pressure applied to the chip ranges from 18 kg to 22 kg, the target temperature range of the pressure plate or the pressure head ranges from 150°C to 200°C, and the pressure-heating time ranges from 2 seconds to 5 seconds.

[0145] In the embodiment of the present disclosure, anisotropic conductive adhesive (ACF) is used to connect an RFID chip (such as Impinj Monza R6) to an antenna pad, wherein the hot pressing parameters are: pressure 20 kg, temperature 180° C., and time 3 seconds.

[0146] The spacing between the labels in the label array formed by the embodiment of the present disclosure is greater than 2 mm. Figure 8 As shown, the degradable film 600 has a thickness of 25 μm to 50 μm and its edges are sealed by heat pressing.

[0147] After the multi-layer sub-substrates are cut in step S400, each sub-substrate can be processed simultaneously in step S500 to improve efficiency.

[0148] Step S600: flip the sub-base, cover the second surface with a degradable film, reserve a chip position, and flip-mount the RFID chip to the antenna at the reserved position to obtain a tag array.

[0149] like Figure 9As shown, the same laminating and flip-chip operations are repeated on the second surface of the sub-substrate, with the specific steps being the same as step S500. The second surface of the substrate, that is, the second surface of the last sub-substrate, has a film. After flipping, the film is first removed, and then covered with a degradable film, and the chip is flipped.

[0150] After the degradable film is applied to the second surface of the substrate and the chip is flipped, and each sub-substrate forms a label array, L-shaped corner marks are placed on the four corners of the second surface of each label unit. The four L-shaped marks form a rectangle. The second surface of the label unit is also the second surface of the sub-substrate.

[0151] After flip-chip mounting on the first surface of each sub-substrate, a film 700 is attached to the first surface of each sub-substrate;

[0152] After flip-chipping the second surface of each sub-base, cutting each label along the gap between each label;

[0153] Remove the adhesive film 700 on the second surface of each sub-base. The adhesive film is a transparent PET film.

[0154] In the embodiment of the present disclosure, each label is cut according to the L-shaped corner marks at the four corners of each label unit. Specifically, the frame of the label unit can be formed by connecting lines according to the L-shaped corner marks at the four corners of the label unit. When cutting, the cutting line is cut at a preset distance from each connecting line of the frame to obtain a label unit, such as Figure 10 shown.

[0155] The method for producing a flexible and degradable radio frequency tag in the embodiment of the present disclosure has a natural degradation rate of the substrate of ≥90% within 180 days, a metal layer recovery rate of >95%, a micro-groove filling process that saves 25% to 35% of metal material usage, and uses laser grooving to ensure circuit precision. Without the need for an etching process, it is more in line with environmental protection requirements. The method of the embodiment of the present disclosure combines low-cost, high-precision, and environmentally friendly radio frequency tag manufacturing solutions, addressing the defects of traditional processes in materials, structure, and efficiency.

[0156] like Figure 11 As shown, another aspect of the embodiment of the present disclosure provides a radio frequency tag, which is manufactured using the flexible and degradable radio frequency tag manufacturing method as described above.

[0157] The above is only a preferred implementation of the embodiment of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the embodiment of the present disclosure. These improvements and modifications should also be considered within the scope of protection of the embodiment of the present disclosure.

Claims

1. A method for producing a flexible and degradable radio frequency tag, characterized in that: The method comprises: Providing a substrate, wherein the substrate is a degradable flexible composite material prepared from lactic acid and nanocellulose; Carving through grooves on the substrate using ultraviolet laser technology to form a pre-designed antenna pattern; The pre-prepared silver-graphene hybrid conductive ink is filled into the groove of the antenna pattern using micro-gravure printing technology, and then sintered and cured at 120°C to 180°C to form the antenna; cutting the substrate transversely along the thickness direction of the substrate to obtain a multi-layer sub-substrate; Covering the first surface of the sub-base with a degradable film, reserving a chip position, and flip-mounting the RFID chip to the antenna at the reserved position; The sub-base is turned over, a degradable film is covered on the second surface, a chip position is reserved, and the RFID chip is flipped onto the antenna at the reserved position.

2. The method according to claim 1, characterized in that The thickness of the substrate is 1 cm to 2 cm; the depth of the sub-substrate groove ranges from 5 μm to 50 μm; The distance between two adjacent grooves is not less than 40 μm.

3. The method according to claim 1, characterized in that The method of cutting the substrate transversely along the thickness direction of the substrate to obtain a multi-layer sub-substrate comprises: Determine the cutting process based on the value parameters of the label application scenario.

4. The method according to claim 3, characterized in that The determining of the cutting process according to the value parameters of the label application scenario includes: When the label value parameter is ≥￥5 / piece, the substrate is cut using a diamond wire saw in combination with a -30℃ to -20℃ low-temperature freezing bonding process; When the label value parameter is less than ￥2 / piece, the substrate is cut using a step-by-step composite process of water jet rough cutting and vibration knife fine cutting.

5. The method according to any one of claims 1 to 4, characterized in that The method of preparing a degradable flexible composite material substrate using lactic acid and nanocellulose comprises: Solution blending-casting film method: Dissolve the PLA particles in chloroform or dichloromethane at 50°C to 70°C and stir until completely dissolved, wherein the concentration of chloroform or dichloromethane is in the range of 5% w / v to 10% w / v; Ultrasonic dispersion of the modified NFC in the PLA solution, wherein the concentration of the modified NFC is in the range of 1 wt% to 20 wt% and the ultrasonic dispersion is carried out for 20 min to 40 min; The mixed solution is poured onto a glass plate and coated to form a film. After the solvent is evaporated at room temperature, it is vacuum-dried at 50°C to 70°C to obtain a flexible composite material substrate. or, Melt blending-extrusion / filming method: PLA and NFC are vacuum dried at 60℃~100℃ for 12 hours or more; A twin-screw extruder is used to extrude the mixture, wherein the NFC addition amount is 5 wt% to 15 wt%, the internal temperature of the twin-screw extruder is 170° C. to 190° C., and the rotation speed is 50 rpm to 100 rpm; Or use internal mixer and mix at 180℃ for 10 minutes; The mixture is formed into a film with a thickness ranging from 50 μm to 200 μm by a hot press; wherein the hot pressing temperature of the hot press is 160° C. to 190° C., the pressure is 8.5 MPa to 11 MPa, and the hot pressing time is 4 minutes to 6 minutes; injection molding into a flexible composite substrate; or, Preparation of flexible fiber membranes, i.e. flexible composite material substrates, by electrospinning: A PLA / NFC mixed solution was prepared, wherein the concentration of PLA was 8% w / v, the concentration of NFC was 1 wt% to 5 wt%, and the solvent was chloroform / DMF = 7:3; The electrospinning parameters were voltage 15-20 kV, receiving distance 15 cm, and flow rate 1 mL / h.

6. The method according to any one of claims 1 to 4, characterized in that Each sub-substrate has a plurality of antenna arrays. Before the through grooves are engraved on the substrate, the method further comprises: Coarse positioning marks are respectively provided at the four corners of the first surface of the sub-base, and fine positioning marks are provided around each preset number of antenna units to be grooved; After the first surface of the sub-base is covered with a degradable film and the chip is flipped, each sub-base forms a plurality of label arrays, and L-shaped corner marks are set at the four corners of each label unit.

7. The method according to claim 6, characterized in that The laser grooving of the first surface of the substrate using ultraviolet laser technology comprises: According to the geometric characteristics of the antenna pattern, the scanning groove mode is pre-set and the laser parameters are adjusted synchronously; Divide the antenna pattern into straight line area, acute angle area, arc area and cross point area; According to the coarse positioning mark and the fine positioning mark, the laser is positioned to the substrate to be grooved and the antenna unit to be grooved respectively; Determine the area of ​​the section to be grooved. If the section to be grooved is a straight line area, use full power, maximum speed, full parameters, and 15% overlap rate to groove. If the groove section to be cut is an acute angle area, horizontal / vertical groove separation is adopted, and the power is linearly reduced to half power groove; overlap 8um; If the groove section to be engraved belongs to the arc area, the arc checking and continuous scanning is adopted, the speed is reduced to 60% of the maximum speed, and the pulse frequency is increased to 80kHz; If the section to be grooved belongs to the cross-intersection area, layered scanning is adopted, with the first layer grooved to 50% depth, and the second layer refined to complete the full depth of the groove.

8. The method according to any one of claims 1 to 7, characterized in that Forming a plurality of label arrays with a spacing greater than 2 mm on each sub-base; After flip-chip mounting on the first surface of each sub-base, a film is attached to the first surface of each sub-base; After flip-chipping the second surface of each sub-base, cutting each label along the gap between each label; The adhesive film on the first surface of each sub-base is removed.

9. The method according to any one of claims 1 to 4, characterized in that The material of the degradable coating is polybutylene succinate (PBS) and its copolymer (PBAT), and the thickness is 25 μm to 50 μm.

10. A radio frequency tag, characterized in that: A radio frequency tag manufactured by the method for manufacturing a flexible and degradable radio frequency tag according to any one of claims 1 to 9.

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