RFID composite conductive paste and manufacturing method thereof, RFID electronic tag

Abstract

The present invention belongs to the technical field of electronic materials and electronic devices, and provides an RFID composite conductive paste and its manufacturing method, and an RFID electronic tag, and the RFID composite conductive paste includes, by weight, 10-25 parts by weight of oil-based special crosslinked resin, 30-50 parts by weight of metal conductive agent, 5-10 parts by weight of two-dimensional carbon-based material, 20-50 parts by weight of organic solvent, 10-20 parts by weight of quick-drying agent, and 2-5 parts by weight of leveling agent. The RFID composite conductive paste provided by the present invention has a high solid content of conductive components, has ideal dispersion and uniformity, and has well-balanced and stable performance.

Description

[Technical Field]

[0001] The present invention relates to the technical fields of electronic materials and electronic equipment, and in particular to a new material, a new process for manufacturing electronic components, and the manufactured electronic components. Specifically, the present invention provides an RFID composite conductive paste, a manufacturing method thereof, and an RFID electronic tag. [Background technology]

[0002] RFID technology, also known as radio frequency identification technology, was originally derived from radar technology and is a type of automatic identification technology. Its working principle is to use radio frequencies for contactless two-way communication and to read and write using electronic tags or radio frequency cards. Its advantage is that it enables fast and accurate identification under contactless conditions, and as the technological foundation of the Internet of Things, related industries and technologies are developing rapidly.

[0003] Conventional RFID tags are made from thin metal films (such as aluminum or copper foils) through a metal etching process, which involves preparing a substrate, applying a photosensitive material, sequentially exposing the material, developing, etching, peeling, rinsing, and drying. This manufacturing method involves complex and tedious steps, high processing costs, low material utilization, and produces a large amount of wastewater containing heavy metals, causing environmental pollution.

[0004] In recent years, with the continuous advancement of RFID component manufacturing technology, methods for manufacturing RFID electronic tags based on printing processes have appeared on the market. This method involves printing a liquid conductive paste onto a substrate in a predetermined pattern using a method such as gravure printing, and then drying and curing the paste by heating, light curing, or other methods to obtain a conductive RFID electronic tag. For example, invention 201810111964.1 discloses a method for manufacturing graphene conductive ink that can be used for RFID electronic tags, and invention 201910216604.2 discloses a graphene-based RFID antenna and a printing method thereof.

[0005] However, the conductive inks for printing RFID electronic tags disclosed in the above-mentioned prior art are all manufactured based on aqueous resins, and during use, they have relatively poor conductive performance, and problems such as poor dispersion and uniformity of the paste system and poor performance stability arise due to the properties of the metal conductive powder and graphene themselves. In addition, the aqueous conductive paste has a slow drying speed, making it difficult to match with the process of a gravure printing machine, resulting in low production capacity. Summary of the Invention

[0006] In order to solve the above-mentioned problems of the prior art, the present invention aims to provide a carbon-based composite conductive paste with a high content of conductive components and ideal dispersion, uniformity, adhesion and stability, and a manufacturing method thereof. RFID electronic tags printed using this conductive paste have excellent conductivity and high consistency in product performance parameters.

[0007] The present invention provides an RFID composite conductive paste containing, by weight, 10 to 25 parts by weight of an oil-based special cross-linked resin, 30 to 50 parts by weight of a metal conductive agent, 5 to 10 parts by weight of a two-dimensional carbon-based material, 20 to 50 parts by weight of an organic solvent, 10 to 20 parts by weight of a quick-drying agent, and 2 to 5 parts by weight of a leveling agent.

[0008] Preferably, the oil-based special crosslinked resin is a polyurethane-modified epoxy resin, and the carrier saturated solid content in the oil-based system of the polyurethane-modified epoxy resin is 55% or more.

[0009] Preferably, the oil-based special cross-linked resin has a dry film density of 1.4 g / m 3 A high cohesive strength chloroacetic acid resin is further added.

[0010] Preferably, the two-dimensional carbon-based material is a physical oil-based graphene paste containing 9 to 11 graphene layers.

[0011] Furthermore, the physical method oil-based graphene paste includes a first step of mixing highly intercalated graphite with a divalent acid ester and an oil-based special cross-linked resin to obtain an initial graphene paste having a magnification of the highly intercalated graphite of 150 to 350 times and a purity of 99% or more; and a second step of exfoliating the initial graphene paste under high pressure through liquid phase exfoliation to obtain a physical oil-based graphene paste having 9 to 11 graphene layers.

[0012] Preferably, the metal conductive agent is one or a mixture of silver-coated copper powder, silver-coated nickel powder, nickel-coated copper powder, and modified conductive copper powder.

[0013] Preferably, the quick-drying agent is one or a mixture of ethyl acetate, butyl acetate, acetone, and cyclohexanone.

[0014] The present invention provides Step S1: Place the oil-based special cross-linked resin and the organic solvent in a container, heat to 50°C, and disperse them at a dispersion frequency of 1800 to 2200 revolutions per minute for a dispersion time of 50 to 70 minutes to obtain a conductive paste carrier; Step S2: Add a two-dimensional carbon material and a metal conductive agent to the conductive paste carrier, and stir for 25 to 35 minutes to obtain a carbon composite conductive paste; Step S3: Add a quick-drying agent and a leveling agent to the carbon-based composite conductive paste, and disperse the paste at a dispersion frequency of 800 to 1200 revolutions per minute for a dispersion time of 25 to 35 minutes to obtain an RFID composite conductive paste; There is further provided a method for manufacturing the RFID composite conductive paste, which includes: using a grinding machine to grind the RFID composite conductive paste (S4).

[0015] Preferably, the grinding machine is a three-roll mill, the roll pitch is 0.4 to 0.6 mm, and the number of grinding operations is one.

[0016] The present invention further provides an RFID electronic tag, comprising an insulating substrate; an RFID radio frequency circuit and a control chip fixed on the surface of the insulating substrate, the control chip being electrically connected to the RFID radio frequency circuit, and the RFID radio frequency circuit being fabricated by gravure printing using the above-mentioned RFID composite conductive paste.

[0017] The present invention has at least the following beneficial effects.

[0018] (1) The RFID composite conductive paste provided by the present invention has a high solid content of conductive components. By modifying and optimizing the resin carrier and graphene paste, a better synergistic effect can be achieved compared to conventional materials, effectively increasing the solid content of the carrier, improving the conductive paste's ability to accommodate solid conductive components, and ensuring that the RFID circuit pattern formed after drying and curing contains sufficient conductive components.

[0019] (2) The RFID composite conductive paste provided by the present invention has ideal dispersion and uniformity. The conductive paste carrier used in the present invention is an oil-based special cross-linked resin, and the oil-based graphene paste obtained by using low-magnification highly intercalated graphite raw material is used as a caulking agent for the metal conductive agent to form a composite conductive structure. The modified and optimized oil-based resin and oil-based graphene material ensure good dispersion and uniformity of the conductive components in the RFID composite conductive paste, thereby further improving the performance indexes of the RFID circuit and the final RFID electronic tag.

[0020] (3) The RFID composite conductive paste provided by the present invention has well-balanced and stable performance. The RFID composite conductive paste provided by the present invention has its component ratio and manufacturing process parameters determined through extensive experiments, ensuring that the properties of fluidity, adhesion, quick-drying and adhesiveness are balanced, and the properties of the conductive paste are stable. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a sample RFID electronic tag. [Figure 2] The microstructure of conventional graphene material. [Figure 3] 1 shows the microstructure of a physical oil-based graphene paste provided by an embodiment of the present invention. [Figure 4] FIG. 4 is a partially enlarged view of FIG. [Figure 5] 1 is a front view of an RFID electronic tag provided by an embodiment of the present invention; [Figure 6] 1 is a side view of an RFID electronic tag provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The invention will be further explained below on the basis of preferred embodiments with reference to the drawings.

[0023] Furthermore, the various components in the drawings are enlarged or reduced in size for ease of understanding, but such an approach is not intended to limit the scope of protection of the present invention.

[0024] Singular words include the plural and vice versa.

[0025] In the description of the embodiments of the present invention, the orientations or positional relationships indicated by terms such as "upper," "lower," "inner," and "outer" are those based on the drawings, or those that are always placed when the product according to the embodiments of the present invention is used, but these terms are merely used for ease and simplicity of description of the present invention and do not indicate or imply that the devices or elements they refer to must have a specific orientation, be configured, or operate in a specific orientation, and therefore cannot be understood as limitations of the present invention. Furthermore, in the description of the present invention, terms such as "first," "second," etc. are used to distinguish different units, but these terms are not limited to the order of manufacture, and cannot be understood as indicating or implying relative importance, and the names of the units may differ in the detailed description of the present invention and the claims.

[0026] The terms used in this specification are used to describe the embodiments of the present invention, but are not intended to limit the present invention. Furthermore, unless otherwise clearly defined and limited, the terms "set," "coupled," and "connected" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. The specific meanings of the above terms in the present invention can be specifically understood by those skilled in the art.

[0027] In order to better explain the technical solution of the present invention, the process flow of manufacturing RFID electronic tags using printing means is first introduced, and the problems and causes of the conductive ink in the prior art are analyzed.

[0028] FIG. 1 is a schematic diagram of a specific RFID electronic tag sample. As shown in FIG. 1, a specific pattern of RFID radio frequency circuit is attached to an insulating substrate. The process flow for manufacturing the above-mentioned RFID electronic tag using printing means is generally as follows: The method includes the steps of injecting or applying liquid conductive ink into grooves having corresponding mirror patterns of radio frequency circuits; scraping off the conductive ink in the grooves with a device such as a doctor blade and removing the conductive ink outside the grooves; transferring the conductive ink onto an insulating substrate by a method such as a roll press to form a forward circuit pattern; and drying and curing the conductive ink to finally obtain an RFID electronic tag.

[0029] To obtain RFID tags with excellent conductivity and consistent product parameters, the printing manufacturing process of RFID tags described above places strict requirements on the performance of the conductive paste used. An ideal conductive paste should have the following properties:

[0030] (1) High solid content of conductive components The RFID radio frequency circuit printed using the conductive paste must have good conductivity and reflectivity against ultra-high frequency radio waves. Therefore, the paste must have an ideal ability to accommodate solid conductive components to ensure that the formed circuit pattern contains sufficient conductive components after drying and curing.

[0031] (2) The conductive component has ideal dispersion and uniformity. If the paste can adequately accommodate the conductive components, the distribution of the conductive components in the paste will affect the conductivity performance of the final RFID circuit and the consistency of product performance parameters. The conductive components must be well dispersed in the paste to ensure conductivity at each location, and must have good uniformity to avoid problems such as unstable conductivity and signal reflection performance at different locations and reduced yields due to uneven distribution or aggregation of the conductive components.

[0032] (3) A better balance between fluidity and adhesion, and between quick-drying and adhesive properties. The conductive paste described above must have good fluidity to ensure the integrity of the circuit pattern during the injection process into the printing gravure, good adhesion to firmly attach the circuit to the insulating substrate, quick drying properties to meet the needs of large-scale mass production, and adhesion between the conductive components in the paste must be ensured to prevent problems such as pattern breakage during the quick drying process. Therefore, it is necessary to modify and optimize each component and adjust the compounding ratio and manufacturing process to achieve an optimal overall effect.

[0033] (4) The properties of the conductive paste material are stable. Conductive paste contains solid and liquid components with various different properties, so it is necessary to modify and optimize each component in the same way to increase the affinity between them, thereby avoiding phenomena such as layering and precipitation in the paste, which could affect the stability of the product.

[0034] However, various conductive inks or conductive pastes disclosed in the prior art have various defects to different degrees, mainly as follows:

[0035] (1) The conductive pastes used in conventional technologies are often produced by simply physically mixing an aqueous resin with a common graphene material and a metal conductive agent (metal powder), and their conductive performance is somewhat inferior.

[0036] (2) Due to the characteristics of the metal conductive powder and graphene themselves, their specific surface area and the surface tension of the aqueous system are both large, making it difficult for the aqueous resin to fully wet their surface. As a result, the entire paste system is difficult to disperse uniformly, and aggregation is likely to occur, which affects the conductivity and parameter consistency of the printed RFID circuit. In addition, stratification and precipitation are likely to occur when left for a long time, resulting in a decrease in the stability of the paste.

[0037] (3) The slow drying speed of water-based conductive paste makes it difficult to match with the gravure printing process, resulting in a slow production speed and making it difficult to realize large-scale mass production.

[0038] In order to solve the various drawbacks of the conductive pastes of the prior art described above, one embodiment of the present invention provides an RFID composite conductive paste containing, by weight, 10-25 parts by weight of an oil-based special cross-linked resin, 30-50 parts by weight of a metal conductive agent, 5-10 parts by weight of a two-dimensional carbon-based material, 20-50 parts by weight of an organic solvent, 10-20 parts by weight of a quick-drying agent, and 2-5 parts by weight of a leveling agent.

[0039] Specifically, the oil-based special cross-linked resin is used to support a conductive component consisting of a metal conductive agent and a two-dimensional carbon material as a base to form an oil-based conductive paste system; the two-dimensional carbon material is used as a caulking agent for the metal conductive agent to form a composite conductive structure; the organic solvent is used to dilute and adjust the concentration and viscosity of the conductive paste; the leveling agent is used to increase the fluidity of the conductive paste; and the quick-drying agent is used to increase the drying speed of the conductive paste.

[0040] In some preferred embodiments of the present invention, the oil-based special crosslinked resin is a polyurethane-modified epoxy resin, and the polyurethane-modified epoxy resin has a higher carrier saturated solids content and a higher dry film density than conventional epoxy resins, and its oil-based system has a carrier saturated solids content of 55% or more and a dry film density of 1.2 g / m 3 That's all.

[0041] Table 1 below shows a comparison of the performance of polyurethane modified epoxy resins and conventional epoxy resins at carrier saturation solids.

[0042] Table 1. Comparison of carrier saturated solids between polyurethane-modified epoxy resin and conventional epoxy resin [Table 1]

[0043] In some embodiments of the present invention, the oil-based special crosslinked resin is obtained by subjecting epoxy resin to polyurethane modification treatment. The modification treatment of epoxy resin is a technique known to those skilled in the art, and the operation, mixing ratio of reactants, reaction conditions, etc. in the implementation process can be set according to the desired performance.

[0044] In some embodiments of the present invention, the oil-based special crosslinked resin may be obtained by directly purchasing the product. For example, the modified epoxy resin and / or modified polyurethane resin produced by Huntsman Company of America may be used as the oil-based special crosslinked resin. The thermoplastic resins produced by this company have excellent dispersibility, which allows the amount of resin used to be significantly reduced without affecting the dispersibility of the conductive paste. This in turn allows the proportion of conductive agents in the overall formulation to be significantly increased, thereby improving the conductivity of the entire paste and significantly improving the performance of printed electronic labels.

[0045] In some preferred embodiments of the present invention, the oil-based special cross-linked resin has a dry film density of 1.4 g / m 3 A high cohesive strength chloroacetic acid resin is further added.

[0046] Table 2 below shows a comparison of the dry film density performance of polyurethane modified epoxy resin, high cohesive strength chloroacetic acid resin and conventional epoxy resin.

[0047] Table 2. Comparison of dry film density between polyurethane-modified epoxy resin, high cohesive strength chloroacetic acid resin, and conventional epoxy resin [Table 2]

[0048] Conventional epoxy resins have high viscosity, making them difficult to prepare as a high-solids conductive paste carrier. They also have poor fluidity, resulting in thick, low-density, and brittle film layers after curing. Because the groove depths used in gravure printing are shallow (micron-level) and the pattern widths are millimeter-level, when conductive pastes made based on conventional epoxy resins are applied to gravure-printed RFID circuits, problems such as poor circuit conductivity and ultra-high frequency radio wave reflection characteristics, insufficient circuit patterns, and susceptibility to breakage can occur.

[0049] The present invention uses polyurethane-modified epoxy resin as an oil-based special cross-linked resin, preferably with a high cohesive chloroacetic acid resin added thereto. The oil-based special cross-linked resin serves as a conductive paste carrier, and the polyurethane-modified epoxy resin contained therein has a higher saturated solids content than conventional epoxy resins, allowing it to carry more conductive components per unit volume, thereby effectively improving the conductive and reflective properties of the printed circuit. The addition of a high cohesive chloroacetic acid resin can reduce the viscosity of the paste and improve the cohesive force of the paste, thereby achieving good dispersion of the powdery conductive components. This effectively increases the density after film formation, reduces the thickness of the dry film, and improves the flexibility of the dry film and its adhesion to the substrate.

[0050] In some embodiments of the present invention, phenoxy resin and / or polyester resin are added to the oil-based special cross-linked resin. The phenoxy resin and polyester resin contribute to the dispersion of the conductive paste, make the appearance of the conductive paste more delicate, improve the printing performance of the conductive paste itself, make the surface of the gravure-printed electronic label smooth and flat, and greatly improve the consistency of performance.

[0051] In some preferred embodiments of the present invention, the metal conductive agent is a mixture of one or more of silver-coated copper powder, silver-coated nickel powder, nickel-coated copper powder, and modified conductive copper powder.

[0052] In some preferred embodiments of the present invention, the two-dimensional carbon-based material is a physical oil-based graphene paste containing 9 to 11 graphene layers, and the physical oil-based graphene paste is A first step of mixing highly intercalated graphite with a divalent acid ester (DBE solvent) and an oil-based special cross-linked resin to obtain an initial graphene paste having a magnification of 150 to 350 times the highly intercalated graphite and a purity of 99% or more; and a second step of exfoliating the initial graphene paste under high pressure through liquid phase exfoliation to obtain a physical oil-based graphene paste having 9 or more and 11 or less graphene layers.

[0053] The graphene material mixed into the conductive paste for RFID electronic tag printing can be used as a filler for the metal powder of the metal conductive agent, and can efficiently bond the metal powder dispersed in the resin carrier, resulting in a synergistic effect that further improves the conductivity and reflective properties of the printed circuit.

[0054] However, the graphene used in prior art is all conventional graphene material, and Figure 2 shows the microstructure of conventional graphene material, which clearly shows thickness unevenness and aggregation. At the same time, conventional graphene material has a large and irregular range of layer numbers, and while the low layer number parts can improve conductivity, the small particle size makes it difficult to exert a packing effect, and the high layer number parts have significantly reduced conductivity. After conventional graphene material that has not undergone the above-mentioned optimization process is added to conductive paste, the irregular microstructure prevents it from creating a good synergistic effect with the conductive metal powder, which may result in poor performance.

[0055] In the present invention, the graphene material added to the conductive paste is an optimized physical oil-based graphene paste, in which the initial graphene paste is obtained by mixing a high-purity highly intercalated graphite raw material with a diacid ester at a low ratio, and the initial graphene paste has a low ratio, high purity, is easy to disperse, and has a good intercalation effect. The initial graphene paste can be liquid-phase exfoliated under high pressure to produce a physical oil-based graphene paste with about 10 graphene layers.

[0056] Figure 3 shows the microstructure of the oil-based graphene paste provided by the embodiment of the present invention, and Figure 4 is a partially enlarged view of Figure 3. As can be seen from Figures 3 and 4, the oil-based graphene paste used in the embodiment of the present invention has a more uniform thickness than conventional graphene materials, and at the same time, the microstructure is optimized and the number of layers is relatively consistent, which can provide excellent conductivity and filling effect at the same time, and form a good synergistic effect with the metal conductive agent, further improving the performance index of the RFID circuit.

[0057] Table 3 below shows a comparison of the performance parameters of the oil-based graphene paste prepared in one specific embodiment of the present invention with conventional graphene materials (the proportion of graphene components, the types and proportions of other components, and the manufacturing process are all the same). Figures 2, 3, and Table 3 show that the oil-based graphene paste prepared in this embodiment of the present invention exhibits improvements in microstructure, filling performance, and conductive performance compared to conventional graphene materials used in the prior art.

[0058] Table 3. Comparison of performance between physical oil-based graphene paste and conventional graphene materials [Table 3]

[0059] In some preferred embodiments of the present invention, the quick-drying agent is a mixture of one or more of ethyl acetate, butyl acetate, acetone, and cyclohexanone. Adding a quick-drying agent to the conductive paste can speed up the drying and curing of the printed RFID circuit, thereby improving the production speed of RFID electronic tags.

[0060] In some preferred embodiments of the present invention, the quick-drying agent may be isoflurane, or a mixture of isoflurane and one or more of the above-mentioned ethyl acetate, butyl acetate, acetone, and cyclohexanone. Isoflurane not only has a quick-drying effect, but also super-disperses and reduces the viscosity of graphene and metal conductive agents, which is beneficial to the fluidity of the entire paste system and improves printing performance.

[0061] In a preferred embodiment of the present invention, a leveling agent is added and the compounding ratio of the leveling agent is adjusted to ensure that the conductive paste is sufficiently filled into the grooves and leveled, and that the RFID circuit pattern transferred to the substrate does not flow around and affect the accuracy of the pattern. As a result, the printed RFID electronic tab has a uniform thickness, stable conductivity, and high consistency.

[0062] In some preferred embodiments of the present invention, the organic solvent is a diacid ester (DBE solvent).

[0063] If the resin content of the conductive paste is too high, the conductivity will deteriorate; if the metal conductive agent content is too high, the paste viscosity will be too high, making production difficult and also disadvantageous in terms of cost control; in addition, there is a strict proportional relationship between the graphene and the metal conductive agent as a caulking agent; if the graphene content is too low, it will be difficult to effectively fill the voids between the metal conductive agents, resulting in reduced conductivity; but if the graphene content is too high, the connection bridge between the metal conductive agents will be inhibited, resulting in reduced conductivity. This has been proven through extensive experiments.

[0064] Due to the various performance needs mentioned above, the performance of the conductive paste cannot be achieved by simply combining the normal effects of the various components contained therein, and especially when the performance and effects of different components affect each other, it is necessary to eliminate the negative effects and amplify the beneficial effects through adjustment of the compounding ratio and modification optimization. The RFID composite conductive paste provided by the present invention has a strictly proportional compounding ratio of each component, and the resin carrier and graphene paste are modified and optimized to achieve a better synergistic effect than conventional materials.

[0065] Another aspect of the present invention provides a method for manufacturing the RFID composite conductive paste, for manufacturing the RFID composite conductive paste, comprising: Step S1: Place the oil-based special cross-linked resin and the organic solvent in a container, heat to 50°C, and disperse them at a dispersion frequency of 1800 to 2200 revolutions per minute for a dispersion time of 50 to 70 minutes to obtain a conductive paste carrier; Step S2: Add a two-dimensional carbon material and a metal conductive agent to the conductive paste carrier, and stir for 25 to 35 minutes to obtain a carbon composite conductive paste; Step S3: Add a quick-drying agent and a leveling agent to the carbon-based composite conductive paste, and disperse the paste at a dispersion frequency of 800 to 1200 revolutions per minute for a dispersion time of 25 to 35 minutes to obtain an RFID composite conductive paste; and step S4 of grinding the RFID composite conductive paste using a grinding machine.

[0066] The RFID composite conductive paste is ground using a three-roll mill to further promote the uniform distribution of conductive components, making it less likely for phenomena such as stratification and precipitation to occur during the printing process, thereby ensuring the stability of the paste's conductive performance and the consistency of the product.

[0067] However, when grinding with a three-roll mill, the more grinding times, the better, and the finer the grinding, the less desirable the results. For the following reasons: Inappropriate grinding times and roll pitch can have a negative effect on the performance of the conductive paste. The selection of roll pitch should be determined by the mesh number of the metal conductive agent. In some specific embodiments of the present invention, the mesh number of the metal conductive agent is 400 to 600 mesh, preferably 500 mesh. If the roll pitch is set too high, the metal conductive agent cannot be effectively ground and dispersed. If the pitch is set too low, the conductive structure of the metal powder and graphene will be destroyed. Furthermore, conductive paste that is not ground will exhibit stratification, resulting in unstable conductivity of the product. Conversely, grinding multiple times will result in the destruction of the conductive structure. Due to the properties of graphene itself, grinding multiple times will also result in reverse coarsening and aggregation, which will affect the conductivity.

[0068] Table 4 below compares the impact of different grinding cycles on the performance of conductive pastes when other manufacturing processes and parameters are the same. As can be seen from the performance comparison in Table 4, the conductive pastes that were not three-roll ground and those that were ground multiple times performed worse than the conductive paste that was ground once. The reasons for this are as follows: the conductive paste that was not three-roll ground exhibited obvious stratification under film printing, the conductive components aggregated within the paste, the dry film surface was uneven, and the conductivity and consistency were deteriorated. The conductivity data after multiple roll grinding cycles was significantly worse. This was mainly due to the destruction of the silver and nickel plating layers in the silver-coated copper powder and nickel-coated copper powder, resulting in a decrease in conductivity and a deterioration in antioxidant performance. After prolonged storage, the performance clearly deteriorated.

[0069] Table 4 Comparison of the effect of different grinding times on the performance of conductive paste [Table 4]

[0070] In a preferred embodiment of the present invention, the grinding machine is a three-roll mill, the roll pitch is 0.4 to 0.6 mm, and the number of grinding passes is one. The preferred process parameters for the above-mentioned grinding process are determined by analyzing a large amount of experimental data. The roll pitch is set to 0.4 to 0.6 mm to more uniformly distribute the aggregated conductive components remaining in the conductive paste after rotation dispersion and stirring, and to remove stratification. Furthermore, the number of grinding passes is limited to avoid damage to the microstructure of the metal conductive agent and ensure the performance of the conductive paste is improved.

[0071] Example 1 The following steps are used to prepare the RFID composite conductive paste.

[0072] Step 1: Add 40 parts by weight of DBE solvent and 10 parts by weight of oil-based special cross-linked resin obtained by mixing polyurethane-modified epoxy resin and high cohesive strength chloroacetic acid resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0073] Step 2: Add 31 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 10%) and 5 parts by weight of graphene conductive paste to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0074] Step 3: Add 10 parts by weight of butyl acetate and 2 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0075] Step 4: Using a three-roll mill with a roll pitch of 0.6 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0076] Example 2 The following steps are used to prepare the RFID composite conductive paste.

[0077] Step 1: Add 31 parts by weight of DBE solvent and 10 parts by weight of oil-based special cross-linked resin obtained by mixing polyurethane-modified epoxy resin and high cohesive strength chloroacetic acid resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0078] Step 2: Add 38 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 5%) and 6 parts by weight of graphene conductive paste to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0079] Step 3: Add 12 parts by weight of butyl acetate and 3 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0080] Step 4: Using a three-roll mill with a roll pitch of 0.5 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0081] Example 3 The following steps are used to prepare the RFID composite conductive paste.

[0082] Step 1: Add 20 parts by weight of DBE solvent and 11 parts by weight of polyurethane-modified epoxy resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0083] Step 2: Add 38 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 3%) and 8 parts by weight of graphene conductive paste to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0084] Step 3: Add 14 parts by weight of butyl acetate and 4 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0085] Step 4: Using a three-roll mill with a roll pitch of 0.4 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0086] Example 4 The following steps are used to prepare the RFID composite conductive paste.

[0087] Step 1: Add 31 parts by weight of DBE solvent and 10 parts by weight of polyurethane-modified epoxy resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0088] Step 2: Add 41 parts by weight of sheet-shaped nano-nickel coated copper powder (nickel content 5%) and 3 parts by weight of highly filled conductive carbon black to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0089] Step 3: Add 12 parts by weight of butyl acetate and 3 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0090] Step 4: Using a three-roll mill with a roll pitch of 0.5 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0091] Example 5 The following steps are used to prepare the RFID composite conductive paste.

[0092] Step 1: Add 24 parts by weight of DBE solvent and 11 parts by weight of polyurethane-modified epoxy resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0093] Step 2: Add 43 parts by weight of modified sheet-shaped nanocopper powder and 4 parts by weight of highly filled conductive carbon black to the above conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0094] Step 3: Add 14 parts by weight of ethyl acetate and 4 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0095] Step 4: Using a three-roll mill with a roll pitch of 0.4 mm, the RFID composite conductive paste is subjected to two passes of roll grinding.

[0096] Example 6 The following steps are used to prepare the RFID composite conductive paste.

[0097] Step 1: Add 24 parts by weight of DBE solvent and 11 parts by weight of oil-based special cross-linked resin obtained by mixing polyurethane-modified epoxy resin and high cohesive strength chloroacetic acid resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0098] Step 2: Add 43 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 3%) and 4 parts by weight of highly filled conductive carbon black to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0099] Step 3: Add 14 parts by weight of butyl acetate and 4 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0100] Step 4: Using a three-roll mill with a roll pitch of 0.4 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0101] Example 7 The following steps are used to prepare the RFID composite conductive paste.

[0102] Step 1: Add 20 parts by weight of DBE solvent and 10 parts by weight of modified polyurethane resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0103] Step 2: Add 53 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 10%) and 5 parts by weight of graphene conductive paste to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0104] Step 3: Add 5 parts by weight of butyl acetate, 5 parts by weight of isoflurane, and 2 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain an RFID composite conductive paste.

[0105] Step 4: Using a three-roll mill with a roll pitch of 0.4 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0106] Example 8 The following steps are used to prepare the RFID composite conductive paste.

[0107] Step 1: Add 20 parts by weight of DBE solvent and 10 parts by weight of saturated polyester resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0108] Step 2: Add 53 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 10%) and 5 parts by weight of highly filled conductive carbon black to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0109] Step 3: Add 5 parts by weight of butyl acetate, 5 parts by weight of isoflurane, and 2 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain an RFID composite conductive paste.

[0110] Step 4: Using a three-roll mill with a roll pitch of 0.5 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0111] Example 9 The following steps are used to prepare the RFID composite conductive paste.

[0112] Step 1: Add 20 parts by weight of DBE solvent, 2 parts by weight of phenoxy resin, and 8 parts by weight of modified polyurethane resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0113] Step 2: Add 53 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 10%), 2 parts by weight of graphene conductive paste, and 3 parts by weight of highly filled conductive carbon black to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0114] Step 3: Add 6 parts by weight of butyl acetate, 4 parts by weight of isoflurane, and 2 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain an RFID composite conductive paste.

[0115] Step 4: Using a three-roll mill with a roll pitch of 0.4 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0116] Example 10 The following steps are used to prepare the RFID composite conductive paste.

[0117] Step 1: Add 20 parts by weight of DBE solvent, 4 parts by weight of saturated polyester resin, and 6 parts by weight of modified polyurethane resin to a stirring tank, heat to 50°C, and disperse and stir using a dispersion disk at a frequency of 2000 rpm for 1 hour to produce a conductive paste carrier.

[0118] Step 2: Add 53 parts by weight of sheet-shaped nano silver-coated copper powder (silver content 10%), 3 parts by weight of graphene conductive paste, and 2 parts by weight of highly filled conductive carbon black to the above-mentioned conductive paste carrier, and continue stirring for 30 minutes to obtain a carbon-based composite conductive paste.

[0119] Step 3: Add 15 parts by weight of isoflurane and 2 parts by weight of leveling agent to the above carbon-based composite conductive paste, and continue stirring for 30 minutes to obtain RFID composite conductive paste.

[0120] Step 4: Using a three-roll mill with a roll pitch of 0.5 mm, the RFID composite conductive paste is subjected to one-time roll grinding.

[0121] Table 5 below shows a comparison of the performance of the RFID printing conductive pastes produced according to preferred Examples 2, 3, 7 and 8 with conductive pastes produced according to conventional techniques.

[0122] Table 5. Performance comparison of the preferred embodiment of the present invention with conductive pastes made with prior art. [Table 5]

[0123] Another embodiment of the present invention further provides an RFID electronic tag. FIGS. 5 and 6 show a top view and a side view, respectively, of an RFID electronic tag according to an embodiment of the present invention. As shown in FIGS. 5 and 6, the RFID electronic tag provided by the present invention comprises an insulating substrate 10, an RFID radio frequency circuit 11 and a control chip 12 fixed on the surface of the insulating substrate, the control chip 12 being electrically connected to the RFID radio frequency circuit 11, and the RFID radio frequency circuit 11 being fabricated by gravure printing using the above-mentioned RFID composite conductive paste.

[0124] Specifically, the RFID composite conductive paste is first poured into the grooves of a gravure roller and scraped (the groove pattern is a mirror image of the RFID radio circuit 11 to be manufactured), then the RFID composite conductive paste in the grooves is transferred to the insulating substrate 10 by rolling between the gravure roller and a plant roller to form the RFID radio circuit 11, and finally the control chip 12 is fixed to the insulating substrate 10 by adhesive or the like, and electrically connected to the RFID radio frequency circuit by welding or the like (the connector 121 in Figures 5 and 6 is the connection point between the control chip 12 and the RFID radio frequency circuit 11). The method of manufacturing an RFID electronic tag using the above gravure printing method is known to those skilled in the art, so a repeated description will not be given here.

[0125] FIG. 5 shows a specific pattern of the RFID radio circuit 11. Those skilled in the art can select or change the specific pattern of the RFID radio circuit and the specification model of the control chip according to actual needs in the process of actually manufacturing an RFID electronic tag, and it is easy to understand that the above selection and change do not deviate from the scope of protection of the claims of the present invention.

[0126] Although the specific embodiments of the present invention have been described in detail above, those skilled in the art may further make some improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A conductive paste used in RFID printing, The composition contains, by weight, 10 to 25 parts by weight of an oil-based cross-linked resin, 30 to 50 parts by weight of a metal conductive agent, 5 to 10 parts by weight of a two-dimensional carbon-based material, 20 to 50 parts by weight of an organic solvent, 10 to 20 parts by weight of a quick-drying agent, and 2 to 5 parts by weight of a leveling agent. Conductive paste.

2. The oil-based crosslinking resin is an epoxy resin. The conductive paste according to claim 1 .

3. The two-dimensional carbon-based material is an oil-based graphene paste containing 9 to 11 graphene layers. The conductive paste according to claim 1 .

4. The metal conductive agent is one or a mixture of silver-coated copper powder, silver-coated nickel powder, nickel-coated copper powder, and modified conductive copper powder. The conductive paste according to claim 1 .

5. The quick-drying agent is one or a mixture of ethyl acetate, butyl acetate, acetone, and cyclohexanone. The conductive paste according to claim 1 .

6. A method for producing the conductive paste according to any one of claims 1 to 5, comprising: Step S1: placing an oil-based cross-linked resin and an organic solvent in a container, heating the container to 50°C, and dispersing the resin at a dispersion frequency of 1800 to 2200 revolutions per minute for a dispersion time of 50 to 70 minutes to obtain a conductive paste carrier; Step S2: Add a two-dimensional carbon-based material and a metal conductive agent to the conductive paste carrier, and stir for 25 to 35 minutes to obtain a carbon-based composite conductive paste; Step S3: Add a quick-drying agent and a leveling agent to the carbon-based composite conductive paste, and disperse the paste at a dispersion frequency of 800 to 1200 revolutions per minute for a dispersion time of 25 to 35 minutes to obtain a conductive paste; and step S4 of grinding the conductive paste using a grinding machine. A method for manufacturing a conductive paste.

7. The grinding machine is a three-roll mill, the roll pitch is 0.4 to 0.6 mm, and the number of grinding passes is one. The method for producing the conductive paste according to claim 6 .

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