Conductive paste, preparation method of conductive paste, preparation method of electronic tag and electronic tag

Abstract

The embodiment of the invention relates to the technical field of electronic tags, in particular to electropaste, a preparation method of the electropaste, a preparation method of an electronic tag and the electronic tag. The conductive paste comprises the following components in parts by weight: 5-10 parts of a binder; 25 to 30 parts of deionized water; 0.5 to 1 part of a dispersant; 0.5 to 1 part of a thickening agent; 60 to 80 parts of silver coated copper powder; wherein the adhesive comprises at least one of ethyl cellulose, water-based acrylic resin and polyvinyl alcohol. The conductive paste is water-based conductive paste using water as a solvent, and compared with traditional organic conductive paste, the water-based conductive paste is more environmentally friendly. The silver-coated copper powder comprises a copper core, and the copper core is wrapped by a silver shell layer. The silver-coated copper powder not only can ensure the performance of the electronic tag by means of the excellent conductivity of the silver shell layer, but also can reduce the cost of the whole electronic tag by using the copper core, and can effectively balance the contradiction between the cost and the stability of the electronic tag.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic tags, and in particular to a conductive paste, a method for preparing the conductive paste, a method for preparing an electronic tag, and an electronic tag. Background Art

[0002] An electronic tag primarily consists of a tag antenna, memory, and control system, the latter of which is typically implemented using chips of varying sizes. Tag antennas are generally manufactured using three methods: etching, coil winding, and printing. Printing offers advantages such as low equipment investment, high production efficiency, low manufacturing costs, flexible antenna structure, and environmental friendliness.

[0003] The printing method usually involves printing the conductive paste directly on the tag substrate so that the conductive paste forms a tag antenna on the tag substrate. Conductive pastes mainly include conductive silver paste, low-dimensional conductive paste (such as conductive paste with carbon nanotubes, graphene or MXene as fillers) or conductive copper paste. Conductive silver paste is relatively expensive. The conductivity of low-dimensional conductive paste is very different from that of metal, which makes the radiation efficiency of the resulting RF antenna low and difficult to meet the needs of practical applications. Copper paste has outstanding cost advantages and high conductivity, but copper itself has active chemical properties and is very prone to oxidation reactions when exposed to air, which greatly reduces the service life of the electronic tag and makes long-term and stable identification impossible. Summary of the Invention

[0004] The embodiments of the present application provide a conductive paste, a method for preparing the conductive paste, a method for preparing an electronic tag, and an electronic tag, which can effectively balance the contradiction between the cost and stability of the electronic tag.

[0005] In order to solve the above technical problems, the embodiments of the present application provide the following technical solutions:

[0006] In a first aspect of the present application, a conductive paste is provided, which comprises the following components in parts by weight: 5 to 10 parts of a binder; 25 to 30 parts of deionized water; 0.5 to 1 part of a dispersant; 0.5 to 1 part of a thickener; and 60 to 80 parts of silver-coated copper powder; wherein the binder comprises at least one of ethyl cellulose, a water-based acrylic resin, and polyvinyl alcohol.

[0007] In an embodiment of the present application, a conductive paste includes an adhesive, deionized water, a dispersant, a thickener, and silver-coated copper powder. This conductive paste is a water-based conductive paste using water as a solvent. Compared to traditional organic conductive pastes, this water-based conductive paste is more environmentally friendly. The silver-coated copper powder includes a copper core coated with a silver shell. The silver-coated copper powder not only ensures the performance of the electronic tag by leveraging the excellent conductivity of the silver shell, but also reduces the overall cost of the electronic tag by utilizing the copper core, effectively balancing the cost and performance stability of the electronic tag.

[0008] In some embodiments, the silver-coated copper powder is a flaky silver-coated copper powder, and in parts by weight, the silver-coated copper powder includes: 45 to 55 parts of a first silver-coated copper powder; 15 to 25 parts of a second silver-coated copper powder; wherein the D 50 The D of the second silver-coated copper powder is 8μm. 50 4μm.

[0009] In some embodiments, the thickener is a polyurethane thickener; and the leveling agent is a silicone leveling agent.

[0010] In some embodiments, the adhesive is ethyl cellulose. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of ethyl cellulose; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 50 parts of first silver-coated copper powder; and 19 parts of second silver-coated copper powder.

[0011] In some embodiments, the adhesive is a water-based acrylic resin. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of water-based acrylic resin; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 55 parts of first silver-coated copper powder; and 24 parts of second silver-coated copper powder.

[0012] In some embodiments, the adhesive is polyvinyl alcohol. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of polyvinyl alcohol; 30 parts of deionized water; 1 part of dispersant; 1 part of thickener; 45 parts of first silver-coated copper powder; and 15 parts of second silver-coated copper powder.

[0013] In a second aspect of the present application, a method for preparing a conductive paste is further provided, the method comprising: taking the raw materials of the conductive paste described in the first aspect; mixing the raw materials of the conductive paste to obtain a conductive paste.

[0014] In the third aspect of the present application, a method for preparing an electronic tag is also provided, which includes: taking the conductive paste described in the first aspect; printing the conductive paste on a tag substrate so that the conductive paste printed on the tag substrate forms an antenna pattern; curing the conductive paste printed on the tag substrate to obtain a tag antenna; electrically connecting the tag antenna to a tag chip to obtain an electronic tag.

[0015] In some embodiments, the curing treatment time is 25 minutes to 35 minutes, and the curing treatment temperature is 110°C to 130°C.

[0016] In a fourth aspect of the present application, an electronic tag is further provided. The electronic tag is prepared according to the method described in the first aspect.

[0017] It should be understood that the contents described in the Summary of the Invention are not intended to define the key or important features of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0019] Figure 1 It is a schematic flow chart of a method for preparing a conductive paste provided in one embodiment of the present application. DETAILED DESCRIPTION

[0020] The principles and spirit of the present disclosure will be described below with reference to several exemplary embodiments shown in the accompanying drawings. It should be understood that the description of these specific embodiments is only intended to enable those skilled in the art to better understand and implement the present disclosure, and is not intended to limit the scope of the present disclosure in any way. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the art.

[0021] As used herein, the term "including" and similar terms should be understood as open inclusion, i.e., "including but not limited to." The term "based on" should be understood as "based at least in part on." The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment." The terms "first," "second," etc. may refer to different or the same objects and are only used to distinguish the objects referred to, and do not imply a specific spatial order, temporal order, order of importance, etc. of the objects referred to.

[0022] An embodiment of the present application provides a conductive paste, which is used to print the tag antenna of a wireless radio frequency identification (RFID) electronic tag. The raw materials of the conductive paste include the following components, calculated by weight: 5 to 10 parts of a binder; 25 to 30 parts of deionized water; 0.5 to 1 part of a dispersant; 0.5 to 1 part of a thickener; and 60 to 80 parts of silver-coated copper powder.

[0023] In an embodiment of the present application, to further enhance the stability of the tag antenna, the adhesive includes at least one of ethyl cellulose, a water-based acrylic resin, and polyvinyl alcohol. The adhesive securely adheres the conductive paste to the surface of the tag substrate. After the conductive paste cures, the adhesive forms a network structure that encapsulates the silver-coated copper powder, maintaining a relatively stable position and preserving the integrity of the conductive network, thereby ensuring the stability of the tag antenna's conductive performance.

[0024] In an embodiment of the present application, a conductive paste comprises an adhesive, deionized water, a dispersant, a thickener, and silver-coated copper powder. This conductive paste is a water-based conductive paste using water as a solvent. Compared to traditional organic conductive pastes, this water-based conductive paste is more environmentally friendly. The silver-coated copper powder comprises a copper core coated with a silver shell. The silver-coated copper powder leverages the excellent conductivity of the silver shell to ensure the performance of the electronic tag while utilizing the copper core to reduce the overall cost of the electronic tag, effectively balancing the cost and performance stability of the electronic tag.

[0025] In some embodiments, the silver-coated copper powder is in the form of flakes to better enable it to form a conductive network. The flakes include a first silver-coated copper powder and a second silver-coated copper powder, each having different average particle sizes. The use of two silver-coated copper powders with different average particle sizes in this embodiment facilitates the formation of a conductive network within the tag, thereby reducing the silver-coated copper powder content while improving the conductive performance of the tag antenna.

[0026] Specifically, in some embodiments, the D of the first silver-coated copper powder is 50 The D of the second silver-coated copper powder is 8μm. 50 is 4μm. Among them, D 50 Also known as median particle size or median diameter, it is used to indicate the average particle size of silver-coated copper powder.

[0027] In some embodiments, in order to reduce the content of silver-coated copper powder while improving the conductive performance of the tag antenna, the silver-coated copper powder includes, by weight: 45 to 55 parts of first silver-coated copper powder; and 15 to 25 parts of second silver-coated copper powder.

[0028] In some embodiments, the thickener is a polyurethane thickener. Compared with other thickeners, the polyurethane thickener can better adjust the viscosity of the conductive paste, improve the printing performance of the conductive paste, and maintain the stability of the composition of the conductive paste.

[0029] In some embodiments, the leveling agent is a silicone leveling agent. Compared with other leveling agents, silicone leveling agents can better reduce the surface tension of the conductive paste, allowing it to spread more evenly on the surface of the tag substrate, which is beneficial to improving the conductive performance of the tag antenna.

[0030] In some embodiments, in order to further improve the performance of the electronic tag, such as reading distance and sensitivity, the adhesive is ethyl cellulose. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of ethyl cellulose; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 50 parts of first silver-coated copper powder; and 19 parts of second silver-coated copper powder.

[0031] In other embodiments, in order to further improve the performance of the electronic tag, the adhesive is a water-based acrylic resin. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of water-based acrylic resin; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 55 parts of first silver-coated copper powder; and 24 parts of second silver-coated copper powder.

[0032] In other embodiments, in order to further improve the performance of the electronic tag, the adhesive is polyvinyl alcohol. The raw materials of the conductive paste include the following components in parts by weight: 5 parts of polyvinyl alcohol; 30 parts of deionized water; 1 part of dispersant; 1 part of thickener; 45 parts of first silver-coated copper powder; and 15 parts of second silver-coated copper powder.

[0033] The present application also provides a method for preparing a conductive paste. Figure 1 The method includes: step 11, taking the raw materials of the conductive paste provided in the above embodiment; step 12, mixing the raw materials of the conductive paste to obtain a conductive paste.

[0034] Specifically, in some embodiments, to further improve the read range and sensitivity of the electronic tag, step 12 specifically includes: thoroughly mixing a binder, deionized water, a dispersant, and a thickener to obtain a first mixture; then placing the first silver-coated copper powder, the second silver-coated copper powder, and the first mixture in a high-speed mixer for mixing to obtain a second mixture. The mixing process can be a multi-stage mixing process, which includes a first stage, a second stage, and a third stage. In the first stage, the speed of the high-speed mixer is 1400 rpm / min to 1500 rpm / min, and the mixing time is 30 seconds to 90 seconds; in the second stage, the speed of the high-speed mixer is 2000 rpm / min to 2500 rpm / min, and the mixing time is 60 seconds to 120 seconds; in the third stage, the speed of the high-speed mixer is 1000 rpm / min to 1200 rpm / min, and the mixing time is 25 seconds to 35 seconds. The second mixture is placed in a three-roll mill for grinding to obtain a conductive paste. The gap between the feed rollers of the three-roll mill was 30 μm, and the gap between the discharge rollers was 15 μm.

[0035] The present application also provides a method for preparing an electronic tag, comprising: preparing the conductive paste provided in the above embodiments; printing the conductive paste on a tag substrate, forming an antenna pattern from the conductive paste printed on the tag substrate; curing the conductive paste printed on the tag substrate to obtain a tag antenna; and electrically connecting the tag antenna to a tag chip to obtain the electronic tag. Specifically, the tag substrate may be coated paper or PET film.

[0036] In some embodiments, in order to improve the performance of the tag antenna, the curing time is 25 minutes to 35 minutes and the curing temperature is 110° C. to 130° C.

[0037] The embodiments of the present application further provide an electronic tag, which is prepared according to the method provided in the above embodiments.

[0038] Several embodiments of the present application are provided below.

[0039] Example 1

[0040] Step 1: Take the raw materials of the conductive paste, which include: 5 parts of water-based acrylic resin; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 55 parts of first silver-coated copper powder; and 24 parts of second silver-coated copper powder.

[0041] Step 2: Fully mix the water-based acrylic resin, deionized water, dispersant and thickener obtained in step 1 to obtain a first mixture; then place the first silver-coated copper powder, the second silver-coated copper powder and the first mixture in a high-speed mixer for mixing to obtain a second mixture. The mixing treatment method can specifically be a multi-stage mixing treatment, which includes a first stage treatment, a second stage treatment and a third stage treatment. In the first stage treatment, the speed of the high-speed mixer is 1500rpm / min and the mixing time is 90s; in the second stage treatment, the speed of the high-speed mixer is 2500rpm / min and the mixing time is 60s; in the third stage treatment, the speed of the high-speed mixer is 1000rpm / min and the mixing time is 30s. The second mixture is placed in a three-roll mill for grinding to obtain a conductive paste. The gap between the feed rollers of the three-roll mill is 30μm, and the gap between the discharge rollers is 15μm.

[0042] Step 3: Print the conductive paste on the label substrate using a screen printing process, and then cure the conductive paste on the label substrate to obtain the label antenna. The curing temperature is 120° C. and the curing time is 30 minutes.

[0043] Step 4: Electrically connect the tag chip (model: impinj 730) to the tag antenna to obtain an RFID electronic tag.

[0044] Example 2

[0045] Step 1: Take the raw materials of the conductive paste, which include: 5 parts of ethyl cellulose; 25 parts of deionized water; 0.5 parts of dispersant; 0.5 parts of thickener; 50 parts of first silver-coated copper powder; and 19 parts of second silver-coated copper powder.

[0046] Step 2: Thoroughly mix the ethyl cellulose, deionized water, dispersant and thickener obtained in step 1 to obtain a first mixture; then place the first silver-coated copper powder, the second silver-coated copper powder and the first mixture in a high-speed mixer for mixing to obtain a second mixture. The mixing treatment method can specifically be a multi-stage mixing treatment, which includes a first stage treatment, a second stage treatment and a third stage treatment. In the first stage treatment, the speed of the high-speed mixer is 1500rpm / min and the mixing time is 30s; in the second stage treatment, the speed of the high-speed mixer is 2000rpm / min and the mixing time is 120s; in the third stage treatment, the speed of the high-speed mixer is 1200rpm / min and the mixing time is 30s. Place the second mixture in a three-roll mill for grinding to obtain a conductive paste. The gap between the feed rollers of the three-roll mill is 30μm, and the gap between the discharge rollers is 15μm.

[0047] Step 3: Print the conductive paste on the label substrate using a screen printing process, and then cure the conductive paste on the label substrate to obtain the label antenna. The curing temperature is 120° C. and the curing time is 30 minutes.

[0048] Step 4: Electrically connect the tag chip (model: impinj 730) to the tag antenna to obtain an RFID electronic tag.

[0049] Example 3

[0050] Step 1: Take the raw materials of the conductive paste, which include: 5 parts of polyvinyl alcohol; 30 parts of deionized water; 1 part of dispersant; 1 part of thickener; 45 parts of first silver-coated copper powder; and 15 parts of second silver-coated copper powder.

[0051] Step 2: Thoroughly mix the polyvinyl alcohol, deionized water, dispersant and thickener obtained in step 1 to obtain a first mixture; then place the first silver-coated copper powder, the second silver-coated copper powder and the first mixture in a high-speed mixer for mixing to obtain a second mixture. The mixing treatment method can specifically be a multi-stage mixing treatment, which includes a first stage treatment, a second stage treatment and a third stage treatment. In the first stage treatment, the speed of the high-speed mixer is 1500rpm / min and the mixing time is 30s; in the second stage treatment, the speed of the high-speed mixer is 2000rpm / min and the mixing time is 120s; in the third stage treatment, the speed of the high-speed mixer is 1200rpm / min and the mixing time is 30s. Place the second mixture in a three-roll mill for grinding to obtain a conductive paste. The gap between the feed rollers of the three-roll mill is 30μm, and the gap between the discharge rollers is 15μm.

[0052] Step 3: Print the conductive paste on the label substrate using a screen printing process, and then cure the conductive paste on the label substrate to obtain the label antenna. The curing temperature is 120° C. and the curing time is 30 minutes.

[0053] Step 4: Electrically connect the tag chip (model: impinj 730) to the tag antenna to obtain an RFID electronic tag.

[0054] The sensitivity (in dBi) and reading distance (in m) of the RFID electronic tags provided in Examples 1-3 were tested using a comprehensive tester. The test results are shown in Table 1.

[0055] Table 1

[0056] Example Reading distance (m) Sensitivity (dBi) 1 9.2 -16.0 2 9.5 -16.3 3 9.4 -16.0

[0057] The test results in Table 1 show that the RFID tags prepared in Examples 1-3 of this application all had read ranges no less than 9.2 meters and sensitivities no less than -16.3 dBi. Therefore, the RFID tags provided in Examples of this application possess high sensitivity and long read ranges, meeting the needs of practical applications. Furthermore, the water-based conductive slurry provided in Examples of this application is environmentally friendly and can reduce pollution generated during the tag production process, providing a promising solution for large-scale RFID tag production.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A conductive paste, characterized in that: The conductive paste is composed of the following raw materials in parts by weight: Wherein, the adhesive includes at least one of ethyl cellulose, water-based acrylic resin and polyvinyl alcohol.

2. The conductive paste according to claim 1, characterized in that The silver-coated copper powder is a flaky silver-coated copper powder, and in parts by weight, the silver-coated copper powder comprises: 45 to 55 parts of first silver-coated copper powder; 15 to 25 parts of the second silver-coated copper powder; Wherein, the D 50 The D of the second silver-coated copper powder is 8μm. 50 4μm.

3. The conductive paste according to claim 2, characterized in that The thickener is a polyurethane thickener; and The leveling agent is an organic silicon leveling agent.

4. The conductive paste according to claim 3, characterized in that The adhesive is ethyl cellulose. The raw material composition of the conductive paste is as follows, calculated by weight:

5. The conductive paste according to claim 3, characterized in that: The adhesive is a water-based acrylic resin. The raw material composition of the conductive paste is as follows, calculated by weight:

6. The conductive paste according to claim 3, characterized in that: The adhesive is polyvinyl alcohol. The raw material composition of the conductive paste is as follows, calculated by weight:

7. A method for preparing a conductive paste, the method comprising: Take the raw materials of the conductive paste according to any one of claims 1 to 6; The raw materials of the conductive paste are mixed to obtain the conductive paste.

8. A method for preparing an electronic tag, characterized in that: The method comprises: Take the conductive paste according to any one of claims 1 to 6; Printing the conductive paste on a label substrate so that the conductive paste printed on the label substrate forms an antenna pattern; curing the conductive paste printed on the tag substrate to obtain a tag antenna; The tag antenna is electrically connected to the tag chip to obtain an electronic tag.

9. The method according to claim 8, characterized in that The curing treatment time is 25 minutes to 35 minutes. The temperature of the curing treatment is 110°C to 130°C.

10. An electronic tag, characterized in that: The electronic tag is prepared according to the method of claim 8 or 9.

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