JP5876285B2 - RFID tag antenna and manufacturing method thereof - Google Patents

Description

  The present invention relates to a silver conductive film and a method for manufacturing the same, and particularly to a silver conductive film used for forming a conductive circuit such as an IC tag antenna for wireless communication and a method for manufacturing the same.

  An IC tag for wireless communication (hereinafter referred to as “IC tag”) is a kind of RFID (Radio Frequency IDentification), and transmits and receives radio waves to and from a semiconductor chip that stores data such as an identification number. A thin and lightweight small electronic device provided with an antenna for the purpose.

  Such an IC tag is expected to be widely used in various usage environments in various fields such as logistics management, and it is desired to reduce the manufacturing cost by mass production and to spread it. In addition, the IC tag antenna needs to have a low electrical resistance in order to increase the data transmission / reception possible distance (communication distance) and reduce data loss during transmission / reception. In addition, IC tags are used in various logistics management fields (eg, tracking of transport containers, traceability, location information management, and clothing management by clothing washers like laundry tags). Therefore, there are many occasions where it is repeatedly bent depending on the usage environment, so that it can not be used as an IC tag due to deterioration of antenna characteristics such as disconnection due to metal fatigue of the antenna or increase in electrical resistance even if it is repeatedly bent. Therefore, it is necessary that the flexibility be good.

  As a method of forming an antenna circuit (conductive circuit) for an IC tag, a method of using a copper wire coil or wire as an antenna, a method of transferring a metal foil such as copper foil or aluminum foil to a substrate, a base such as a plastic film For example, there is a method of etching the metal foil after masking the metal foil laminated on the material with an etching resistant ink by printing an antenna circuit pattern.

  However, these methods are limited in productivity and are not suitable for mass production, so that it is difficult to further reduce manufacturing costs. Of these methods, in the method of transferring the metal foil to the substrate and the method of etching the metal foil, the metal foil is manufactured by rolling or the like, but the ratio of the metal in the metal foil is almost 100%. Since the value is high, an IC tag in which an antenna circuit is formed of a metal foil has a problem of poor flexibility although it has good electrical characteristics. In addition, in an IC tag in which an antenna circuit is formed with a metal foil, a metal foil with a film thickness of about 10 to 50 μm is generally used. However, if the metal foil is too thick, the properties of the metal plate become close to the substrate. There is a possibility that the metal foil peels off from the base material when the IC tag is bent. Furthermore, since the ratio of the metal in the metal foil is high, stress is concentrated on the bent surface when the IC tag is bent, and cracks are easily generated on the bent surface. As a result, deterioration of electrical characteristics and disconnection occur. It will not function as an IC tag antenna. On the other hand, in order to improve the flexibility of the IC tag, if the metal ratio is reduced using a conductive film made of a metal component and a resin component instead of the metal foil, the flexibility is generally improved by stress relaxation. However, when the amount of the metal component is reduced, the electrical resistance is deteriorated and the characteristics sufficient for an IC tag antenna are not satisfied.

  As a method of manufacturing an antenna for an IC tag that forms a conductive circuit having good adhesion to a substrate without using a metal foil, a water-based conductive ink containing 40% by mass or less of silver particles is formed into a film by flexographic printing. There has been proposed a method of manufacturing an IC tag antenna by forming a conductive film having a thickness of 0.1 to 0.5 μm on the surface of a film-like base material by applying and drying on the surface of the base material ( For example, see Patent Document 1).

JP 2010-268073 A (paragraph numbers 0030 and 0059)

  In the method of Patent Document 1, an IC tag antenna having a low electrical resistance can be mass-produced to reduce the manufacturing cost. However, a thickness of 0.1 to 0.1 mm can be obtained by using a conductive ink having a low silver particle content. Since a thin conductive film of 0.5 μm is formed and the ratio of silver in the conductive film is as high as almost 100%, the flexibility is similar to the method of transferring the metal foil to the substrate and the method of etching the metal foil. There is a problem that is bad.

  Therefore, in view of such conventional problems, the present invention provides a silver conductive film capable of mass-producing a conductive circuit such as an IC tag antenna having excellent electrical characteristics and flexibility at low cost and a method for manufacturing the same. With the goal.

  As a result of intensive studies to solve the above problems, the present inventors produce a silver conductive film containing a sintered body of 10 to 50% by volume of silver particles and having a volume resistivity of 3 to 100 μΩ · cm. Thus, it was found that a silver conductive film capable of mass-producing a conductive circuit such as an IC tag antenna having excellent electrical characteristics and flexibility at low cost can be manufactured, and the present invention has been completed.

  That is, the silver conductive film according to the present invention includes a sintered body of 10 to 50% by volume of silver particles and has a volume resistivity of 3 to 100 μΩ · cm. The amount of the sintered body of silver particles contained in the silver conductive film is preferably 30 to 50% by volume. Moreover, it is preferable that the surface resistivity of this silver electrically conductive film is 0.5 ohm / square or less, and it is preferable that it is 1-6 micrometers in thickness.

  Moreover, the manufacturing method of the silver electrically conductive film by this invention forms said silver electrically conductive film on a board | substrate by baking after apply | coating the silver particle dispersion liquid containing 50-70 mass% silver particle to a board | substrate. It is characterized by. In this method for producing a silver conductive film, the silver particle dispersion is preferably applied to the substrate by flexographic printing, preferably by repeating flexographic printing a plurality of times, and flexographic printing is performed 2 to 4 times. More preferably, the process is repeated. In this method for producing a silver conductive film, the average particle size of silver particles is preferably 20 nm or less.

  Furthermore, the RFID tag antenna according to the present invention is formed of the silver conductive film. An RFID tag according to the present invention includes an RFID tag antenna formed of the silver conductive film and an IC chip.

  In the present specification, the “average particle diameter of silver particles” refers to an average primary particle diameter that is an average value of primary particle diameters obtained by transmission electron micrographs (TEM images) of silver particles.

  ADVANTAGE OF THE INVENTION According to this invention, the silver electrically conductive film which can mass-produce cheaply conductive circuits, such as an IC tag antenna excellent in the electrical property and the flexibility, can be manufactured.

It is a figure explaining the shape which printed Ag ink on the base material in an Example and a comparative example. It is a figure which shows roughly the dipole antenna created using the electrically conductive film created in the Example and the comparative example. It is a figure which shows roughly the sample for a bending test used in the Example and the comparative example. It is a figure explaining the bending test performed in the Example and the comparative example, (b) is a figure which shows schematically the sample for a bending test which expanded the part enclosed by the dotted circle of (a).

  An embodiment of the silver conductive film according to the present invention includes a sintered body of 10 to 50% by volume of silver particles and has a volume resistivity of 3 to 100 μΩ · cm. When the amount of the sintered body of silver particles in the silver conductive film is less than 10% by volume, the amount of the sintered body of silver particles in the silver conductive film is too small and the conductivity is deteriorated, so that the IC tag antenna is formed. When used, it will not function as an IC tag antenna. On the other hand, when the amount of silver particles in the silver conductive film exceeds 50% by volume, stress is concentrated on the bent surface when the IC tag is bent when used for forming an antenna for an IC tag, and cracks are generated on the bent surface. Is likely to occur. As a result, deterioration of electrical characteristics and disconnection are likely to occur, and the possibility of not functioning as an IC tag antenna increases. In particular, if the amount of silver particles in the silver conductive film is 30 to 50% by volume, when used for forming an IC tag antenna, the communication distance at a frequency of 955 MHz is equal to or greater than the conventional communication distance. It is more preferable that the amount of silver particles in the silver conductive film is 30 to 50% by volume because the thickness is 0.0 m or more and the flexibility is good. In addition, when the volume resistivity of the silver conductive film is in the range of 3 to 100 μΩ · cm, when used for the formation of an antenna for an IC tag, the communication distance is lengthened to ensure the transmission / reception of the data of the IC tag with the reader / writer. Therefore, data loss during transmission / reception by the IC tag antenna is less likely to occur.

  The surface resistivity of the silver conductive film is preferably 0.5Ω / □ or less. When the surface resistivity of the silver conductive film is 0.5Ω / □ or less, when used to form an antenna for an IC tag, the communication distance is increased and the IC tag data is reliably transmitted and received with the reader / writer. Therefore, data loss during transmission / reception by the IC tag antenna is less likely to occur.

  Further, the thickness of the silver conductive film is preferably 1 to 6 μm. The thinner the silver conductive film, the more advantageous in terms of cost. However, when the thickness is less than 1 μm, the electrical resistance in the UHF band increases due to the skin effect when used for forming an IC tag antenna or the like, and the communication distance. Becomes shorter.

  Moreover, in embodiment of the manufacturing method of the silver electrically conductive film by this invention, after apply | coating the silver particle dispersion liquid containing 50-70 mass% silver particles to a board | substrate, it baked, said silver electrically conductive film is carried out on a board | substrate. To form. When the silver particle content in the silver particle dispersion is less than 50% by mass, it becomes difficult to form the silver conductive film on the substrate, and the amount of the sintered body of silver particles in the silver conductive film is too small. When the electrical conductivity deteriorates and the electric resistance increases and exceeds 70% by mass, the viscosity of the silver particle dispersion becomes high, and it becomes difficult to apply by flexographic printing or the like.

  In this method for producing a silver conductive film, the silver particle dispersion is preferably applied to the substrate by flexographic printing, and preferably by repeating flexographic printing a plurality of times. In particular, when the flexographic printing is repeated 2 to 4 times, the balance between the amount of the sintered silver particles in the silver conductive film formed on the substrate and the electrical resistance of the silver conductive film becomes good. More preferably, it is repeated ~ 4 times.

  In this method for producing a silver conductive film, the average particle size of the silver particles is preferably 20 nm or less, and preferably 5 to 15 nm. When the average particle size of the silver particles is about several nanometers to several tens of nanometers, the specific surface area increases and the melting point decreases dramatically. (That is, the low-temperature sinterability of the silver nanoparticles can be obtained). However, when the average particle size of the silver particles is larger than 20 nm, it is difficult to obtain the low-temperature sinterability of the silver nanoparticles.

  In addition, the average particle diameter (primary particle average diameter) of the silver particles is, for example, 60% by mass of Ag particles (silver particles having an average particle diameter of 10 nm), 3.0% by mass of vinyl chloride copolymer latex, and 2.0% by mass. 2 parts by mass of Ag ink containing silver particles such as Ag ink (PFI-700 type manufactured by P-Chem Associates, Inc.) containing 2% by mass of polyurethane thickener and 2.5% by mass of propylene glycol, and 2 parts by mass of oleic acid After being added to a mixed solution of a part and dispersed by ultrasonic waves, the obtained dispersion solution is dropped onto a Cu microgrid with a supporting film and dried, and silver particles on the microgrid are observed with a transmission electron microscope (JEOL). An image observed in a bright field at an acceleration voltage of 100 kV with a JEM-100 CXMark-II type manufactured by Co., Ltd., magnification of 300,000 And can be calculated from the obtained TEM image. The primary particle average diameter of the silver particles can be calculated using, for example, image analysis software (A Image-kun (registered trademark) manufactured by Asahi Kasei Engineering Co., Ltd.). This image analysis software discriminates and analyzes individual particles based on color shading. For example, for a 300,000-fold TEM image, the “particle brightness” is “dark” and “noise removal filter”. Is “Yes”, “Circular threshold” is “20”, and “Overlapping degree” is “50”, and circular particle analysis is performed to measure the primary particle diameter of 200 or more particles. An average diameter can be calculated | required and it can be set as an average primary particle diameter. In addition, what is necessary is just to make measurement impossible when there are many condensed particles and irregular-shaped particles in a TEM image.

  Hereinafter, the Example of the silver electrically conductive film by this invention and its manufacturing method is described in detail.

[Examples 1 to 4]
First, 60% by mass of Ag particles (silver particles having an average particle size of 10 nm), 3.0% by mass of vinyl chloride copolymer latex, 2.0% by mass of polyurethane thickener, 2.5% by mass of propylene glycol, Ink ink (PFI-700 type manufactured by P-Chem Associates, Inc.) was prepared.

Next, flexographic printing machine (JEM Flex, a multi-purpose fine printing machine manufactured by JEOL Ltd.) and flexographic printing plate (manufactured by Watanabe Gosando Co., Ltd.) AWP grade DEF, 150 lines of surface treatment, 96 DOT%), anilox capacity of 8 cc / m ² (400 lines / inch), printing speed of 20 m / min, printing frequency once (Example 1), twice (Example 1) Example 2) Three times (Example 3) and four times (Example 4) on a base material (PET (polyethylene terephthalate) film Melinex 545 (Melinex: registered trademark)) 10 manufactured by Dupontidine Film Co., Ltd. As shown in FIG. 1, after printing the above Ag ink so as to form five substantially rectangular films 12 having a size of about 3 cm × 15 cm, The printed material was heat-treated at 140 ° C. for 30 seconds on the rate and baked to obtain a conductive film (silver conductive film).

  Next, the produced conductive film was cut into two substantially rectangular shapes of 5.0 mm × 78.5 mm together with the substrate, and as shown in FIG. 2, an adhesive release film (type PET38 manufactured by Lintec Corporation). After the dipole antenna 14 is pasted on top, an anisotropic conductive adhesive (ACP) (TAP0604C (Au / Ni coated polymer particles) manufactured by Kyocera Chemical Co., Ltd.) is applied to the IC chip mounting portion of the dipole antenna 14. Apply thinly, place IC chip (Monza2 made by Impinj) 16 on this ACP, and apply pressure of 1.0N at 160 ° C with thermocompression bonding equipment (TTS300 made by Mühlbauer) for 10 seconds. Then, the IC chip 16 is fixedly connected to the dipole antenna 14 and connected to the dipole antenna 14. 16 was the implementation.

  For the IC chip-mounted dipole antenna thus fabricated, the film thickness, electrical resistance (line resistance), and surface resistivity of the conductive film were measured, and the volume resistivity of the conductive film and the metal (Ag) in the conductive film were measured. The percentage was calculated.

  The film thickness of the conductive film was measured by measuring the height difference between the surface of the substrate on which the conductive film was formed and the surface of the conductive film using a laser microscope (model VK-9700 manufactured by KEYENCE), and averaged It was determined by calculating the value. As a result, the film thickness of the conductive film was 1.4 μm in Example 1, 2.1 μm in Example 2, 3.0 μm in Example 3, and 3.6 μm in Example 4.

  For the electrical resistance (line resistance) of the conductive film, the electrical resistance in the longitudinal direction of one conductive film (5.0 mm × 78.5 mm) of the dipole antenna was measured with a tester (model CDM-03D manufactured by CUSTOM). As a result, the electric resistance of the conductive film was 5.0Ω in Example 1, 1.3Ω in Example 2, 0.8Ω in Example 3, and 0.6Ω in Example 4.

  The surface resistivity of the conductive film is obtained by cutting the conductive film into a size of 2.0 cm × 2.0 cm and using a surface resistivity meter (Lorestar GP manufactured by Mitsubishi Chemical Analytic Co., Ltd.) by a four-terminal method. It was measured. As a result, the surface resistivity of the conductive film was 0.25Ω / □ in Example 1, 0.06Ω / □ in Example 2, 0.03Ω / □ in Example 3, 0.02Ω / □ in Example 4. Met.

  The volume resistivity of the conductive film was determined from the film thickness, electrical resistance, and area of the conductive film (the area of one conductive film of the dipole antenna (5.0 mm × 78.5 mm)). As a result, the volume resistivity of the conductive film was 44.6 μΩ · cm in Example 1, 17.4 μΩ · cm in Example 2, 15.3 μΩ · cm in Example 3, and 13.6 μΩ · cm in Example 4. Met.

The ratio of the metal (Ag) in the conductive film is obtained by dissolving a conductive film having a printed area of 2.6 cm × 13.1 cm in a concentrated nitric acid solution (of a known weight), and obtaining the Ag concentration in the solution by ICP emission spectrometry. After calculating the weight (g) of Ag in the conductive film, the Ag volume (cm ³ ) is determined from the Ag density of 10.5 g / cm ³ , and the conductive film thickness and printed area (2.6 cm) are calculated. × 13.1 cm) determine the volume of the conductive film from was calculated from the volume of Ag (cm ³⁾ × 100 / conductive volume (cm ^3). As a result, the ratio of Ag in the conductive film was 22.4% by volume in Example 1, 31.0% by volume in Example 2, 37.1% by volume in Example 3, and 48.3% by Example 4. %Met.

  Next, with respect to the produced IC chip-mounted dipole antenna, a frequency range (ISO / IEC) of 800 MHz to 1100 MHz is used in a anechoic box (MY1530 manufactured by Micronics) using a communication distance measuring device (tagformance manufactured by Voyantic). The communication distance (based on 18000-6C standard) was measured. Prior to this measurement, the environment was set under these conditions (setting using a reference tag attached to tagformance). As a result, the communication distance at a frequency of 955 MHz was 3.8 m in Example 1, 4.2 m in Example 2, 4.4 m in Example 3, and 4.2 m in Example 4.

  Next, as shown in FIG. 3, the conductive film produced in this example was cut into a substantially rectangular conductive film 12 ′ having a size of 5.0 mm × 20.0 mm, and an adhesive release film (Lintec Corporation) was cut. A sample 20 for bending test was prepared by pasting on a manufactured type PET38) 18. As shown in FIG. 4, the portion of the conductive film 12 ′ of the bending test sample 20 is rubbed against an iron column 22 of R = 0.5 mm with a force of 5.0 N and bent by 90 °. The line resistance (tester) after 10 cm, 100 times and 500 times of movement in the direction was measured, and the resistance deterioration rate (from (line resistance after operation × 100 / line resistance before test)) ( 100%) when the line resistance does not change. As a result, the resistance deterioration rate was 100% after 10 times, 100 times, and 500 times in Examples 1 and 2, and 100% and 500 times after 10 times and 100 times in Example 3. It was 125% later, and in Example 4, it was 100% after 10 times, 150% after 100 times, and 180% after 500 times.

  The conditions and results of Examples 1 to 4 are shown in Tables 1 to 3.

[Comparative Example 1, Examples 5-7]
First, vinyl chloride copolymer latex, polyurethane thickener and propylene glycol were added to the Ag ink used in Examples 1 to 4, and 50% by mass of Ag particles (silver particles having an average particle size of 10 nm) and 18.4% by mass. An Ag ink containing a vinyl chloride copolymer latex, 2.0% by mass of polyurethane thickener, and 2.5% by mass of propylene glycol was prepared.

  Except for using this Ag ink, the number of times of printing was 1 time (Comparative Example 1), 2 times (Example 5), 3 times (Example 6) and 4 times in the same manner as in Examples 1 to 4. As Example 7, after obtaining a conductive film, an IC chip-mounted dipole antenna and a bending test sample were prepared, and the film thickness, electrical resistance, and surface resistivity of the conductive film were measured, and the volume resistance of the conductive film was measured. The ratio and the ratio of Ag in the conductive film were calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the film thickness of the conductive film was 1.7 μm in Comparative Example 1, 2.5 μm in Example 5, 3.4 μm in Example 6, and 4.8 μm in Example 7, and the electrical resistance of the conductive film was In Comparative Example 1, measurement was not possible due to overload (OL), in Example 5, 5.0Ω, in Example 6, 2.5Ω, and in Example 7, 1.5Ω. In Example 1, measurement was impossible due to overload (OL), in Example 5, it was 0.43Ω / □, in Example 6, 0.18Ω / □, and in Example 7, 0.10Ω / □. The volume resistivity of the conductive film cannot be calculated by overload (OL) in Comparative Example 1, 78.7 μΩ · cm in Example 5, 53.5 μΩ · cm in Example 6, and 46.1 μΩ in Example 7. -It was cm. The ratio of Ag in the conductive film was 8.5% by volume in Comparative Example 1, 15.5% by volume in Example 5, 17.5% by volume in Example 6, and 18.8% by volume in Example 7. Met. The communication distance at a frequency of 955 MHz was 0.0 m in Comparative Example 1, 3.7 m in Example 5, 3.7 m in Example 6, and 3.8 m in Example 7. Furthermore, the resistance deterioration rate could not be calculated due to overload (OL) in Comparative Example 1, and in Examples 5 to 7, all after 10 times, after 100 times, and after 500 times were 100%.

  The conditions and results of Examples 5 to 7 and Comparative Example 1 are shown in Tables 1 to 3.

[Examples 8 to 10, Comparative Example 2]
First, the Ag ink used in Examples 1 to 4 was centrifuged at 3000 rpm for 10 minutes, and then the supernatant was removed to prepare an Ag ink in which the concentration of Ag particles was adjusted to 70% by mass.

  Except for using this Ag ink, the number of times of printing was 1 (Example 8), 2 (Example 9), 3 (Example 10) and 4 times in the same manner as in Examples 1 to 4, respectively. (Comparative Example 2) After obtaining a conductive film, an IC chip-mounted dipole antenna and a sample for bending test were prepared, and the film thickness, electrical resistance, and surface resistivity of the conductive film were measured, and the volume resistance of the conductive film was measured. The ratio and the ratio of Ag in the conductive film were calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the film thickness of the conductive film was 1.7 μm in Example 8, 2.5 μm in Example 9, 2.8 μm in Example 10, and 3.1 μm in Comparative Example 2, and the electrical resistance of the conductive film was Example 8 is 3.1Ω, Example 9 is 1.1Ω, Example 10 is 0.6Ω, and Comparative Example 2 is 0.4Ω. The surface resistivity of the conductive film is 0.19Ω in Example 8. / □, 0.09Ω / □ in Example 9, 0.03Ω / □ in Example 10, and 0.01Ω / □ in Comparative Example 2. The volume resistivity of the conductive film was 32.8 μΩ · cm in Example 8, 17.4 μΩ · cm in Example 9, 10.8 μΩ · cm in Example 10, and 7.9 μΩ · cm in Comparative Example 2. there were. The proportion of Ag in the conductive film was 25.6% by volume in Example 8, 32.7% by volume in Example 9, 43.3% by volume in Example 10, and 54.7% by volume in Comparative Example 2. Met. The communication distance at a frequency of 955 MHz was 3.8 m in Example 8, 4.2 m in Example 9, 4.2 m in Example 10, and 4.4 m in Comparative Example 2. Furthermore, the resistance deterioration rate was 100% after 10 times, 100 times, and 500 times in Example 8, and 100% after 10 times and 100 times in Example 9, and 120 after 500 times. In Example 10, 100% after 10 times, 110% after 100 times, 150% after 500 times, and in Comparative Example 2, 100% after 10 times, 350% after 100 times, 500% It was 1200% later.

  The conditions and results of Examples 8 to 10 and Comparative Example 2 are shown in Tables 1 to 3.

[Examples 11 to 13, Comparative Examples 3 and 4]
Except for an anilox capacity of 20 cc / m ² (150 lines / inch), the number of times of printing was 1 (Example 11), 2 (Example 12), and 3 times in the same manner as in Examples 1-4. (Example 13) After obtaining a conductive film 4 times (Comparative Example 3) and 8 times (Comparative Example 4), an IC chip-mounted dipole antenna and a sample for bending test were prepared, While measuring electrical resistance and surface resistivity, the volume resistivity of the electrically conductive film and the ratio of Ag in the electrically conductive film were calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the film thickness of the conductive film was 2.2 μm in Example 11, 3.6 μm in Example 12, 5.6 μm in Example 13, 7.5 μm in Comparative Example 3, and 11.4 μm in Comparative Example 4. The electrical resistance of the conductive film is 1.1Ω in Example 11, 0.5Ω in Example 12, 0.1Ω in Example 13, 0.1Ω in Comparative Example 3, and 0.1Ω in Comparative Example 4. The surface resistivity of the conductive film is 0.06Ω / □ in Example 11, 0.02Ω / □ in Example 12, 0.01Ω / □ in Example 13, 0.01Ω / □ in Comparative Example 3, and comparison. In Example 4, it was 0.01Ω / □. The volume resistivity of the conductive film was 15.4 μΩ · cm in Example 11, 11.5 μΩ · cm in Example 12, 3.6 μΩ · cm in Example 13, 4.8 μΩ · cm in Comparative Example 3, In Comparative Example 4, it was 7.3 μΩ · cm. The proportion of Ag in the conductive film was 28.5% by volume in Example 11, 38.5% by volume in Example 12, 49.2% by volume in Example 13, and 54.9% by volume in Comparative Example 3. In Comparative Example 4, it was 70.1% by volume. The communication distance at a frequency of 955 MHz was 3.9 m in Example 11, 4.2 m in Example 12, 4.5 m in Example 13, 4.5 m in Comparative Example 3, and 4.7 m in Comparative Example 4. It was. Further, the resistance deterioration rate was 100% after 10 times, 100 times, and 500 times in Example 11, and 100% after 10 times and 100 times in Example 12, and 125 after 500 times. In Example 13, 100% after 10 times, 150% after 100 times, 180% after 500 times, and in Comparative Example 3, 200% after 10 times, 400% after 100 times, 500% After 1400%. In Comparative Example 4, since the wire was disconnected within 10 times, the resistance deterioration rate could not be obtained.

  Tables 1 to 3 show the conditions and results of Examples 11 to 13 and Comparative Examples 3 to 4.

[Comparative Examples 5 to 8]
First, vinyl chloride copolymer latex, polyurethane thickener and propylene glycol were added to the Ag ink used in Examples 1 to 4, and 40% by mass of Ag particles (silver particles having an average particle size of 10 nm) and 33.8% by mass. An Ag ink containing a vinyl chloride copolymer latex, 2.0% by mass of polyurethane thickener, and 2.5% by mass of propylene glycol was prepared.

  Except for using this Ag ink, the number of times of printing was 1 time (Comparative Example 5), 2 times (Comparative Example 6), 3 times (Comparative Example 7), and 4 times in the same manner as in Examples 1 to 4. As (Comparative Example 8), after obtaining a conductive film, an IC chip-mounted dipole antenna and a bending test sample were prepared, and the film thickness, electrical resistance, and surface resistivity of the conductive film were measured, and the volume resistance of the conductive film was measured. The ratio and the ratio of Ag in the conductive film were calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the film thickness of the conductive film was 1.5 μm in Comparative Example 5, 2.4 μm in Comparative Example 6, 3.6 μm in Comparative Example 7, and 5.0 μm in Comparative Example 8, and the electrical resistance of the conductive film was In Comparative Example 5, measurement is impossible due to overload (OL), in Comparative Example 6 is 280.0Ω, in Comparative Example 7 is 75.0Ω, in Comparative Example 8 is 36.0Ω, and the surface resistivity of the conductive film is Comparative Example In Example 5, measurement was impossible due to overload (OL), 114.0 Ω / □ in Comparative Example 6, 35.5 Ω / □ in Comparative Example 7, and 7.4 Ω / □ in Comparative Example 8. Further, the volume resistivity of the conductive film could not be calculated by overload (OL) in Comparative Example 5, was 4280 μΩ · cm in Comparative Example 6, 1705 μΩ · cm in Comparative Example 7, and 1140 μΩ · cm in Comparative Example 8. The proportion of Ag in the conductive film was 5.7% by volume in Comparative Example 5, 6.4% by volume in Comparative Example 6, 5.9% by volume in Comparative Example 7, and 7.0% by volume in Comparative Example 8. Met. The communication distance at a frequency of 955 MHz was 0.0 m in Comparative Example 5, 0.0 m in Comparative Example 6, 1.8 m in Comparative Example 7, and 2.1 m in Comparative Example 8. Furthermore, the resistance deterioration rate could not be calculated due to overload (OL) in Comparative Example 5, and in Comparative Examples 6 to 8, all after 10 times, after 100 times, and after 500 times were 100%.

  Tables 1 to 3 show the conditions and results of Comparative Examples 5 to 8.

[Comparative Examples 9 to 10]
Instead of the conductive films obtained in Examples 1 to 4, Ag foils (manufactured by Takeuchi Metal Foil Industry Co., Ltd., 100 mm × 100 mm) having a thickness of 1 μm (Comparative Example 9) and 3 μm (Comparative Example 10) were cut. The IC chip-mounted dipole antenna, the bending test sample, and the bending test sample were prepared in the same manner as in Examples 1 to 4 except that the conductive film was used as the conductive film (the ratio of Ag in the conductive film was 100%). While measuring the electrical resistance and surface resistivity of the conductive film, the volume resistivity of the conductive film was calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the electrical resistance of the conductive film was 0.2Ω in Comparative Example 9 and 0.1Ω in Comparative Example 10, and the surface resistivity of the conductive film was 0.01Ω / □ in Comparative Example 9 and in Comparative Example 10 It was 0.01Ω / □. The volume resistivity of the conductive film was 1.6 μΩ · cm in Comparative Example 9 and 1.9 μΩ · cm in Comparative Example 10. The communication distance at a frequency of 955 MHz was 4.0 m in Comparative Example 9 and 4.4 m in Comparative Example 10. Furthermore, the resistance deterioration rate is 100% after 10 times, 200% after 100 times, and 800% after 500 times in Comparative Example 9, and 100% after 10 times and 150% after 100 times in Comparative Example 10. %, After 500 times it was 400%.

  The conditions and results of these Comparative Examples 9 to 10 are shown in Tables 1 to 3.

[Comparative Examples 11 to 13]
Instead of the conductive films obtained in Examples 1 to 4, Al foils with a thickness of 3 μm (Comparative Example 11), 6 μm (Comparative Example 12) and 12 μm (Comparative Example 13), respectively, manufactured by Takeuchi Metal Foil Industry Co., Ltd., 100 mm × 100 mm) was cut and used as a conductive film (the proportion of Al in the conductive film was 100%). By the same method as in Examples 1 to 4, an IC chip-mounted dipole antenna, a bending test sample, and A sample for bending test was prepared, and the electrical resistance and surface resistivity of the conductive film were measured, and the volume resistivity of the conductive film was calculated. Further, the communication distance of the IC chip mounted dipole antenna was measured by the same method as in Examples 1 to 4, and the resistance deterioration rate of the bending test sample was obtained.

  As a result, the electrical resistance of the conductive film was 0.2Ω in Comparative Example 11, 0.2Ω in Comparative Example 12, and 0.2Ω in Comparative Example 13, and the surface resistivity of the conductive film was that of Comparative Examples 11-13. Both were 0.01Ω / □. The volume resistivity of the conductive film was 3.8 μΩ · cm in Comparative Example 11, 7.6 μΩ · cm in Comparative Example 12, and 15.3 μΩ · cm in Comparative Example 13. The communication distance at a frequency of 955 MHz was 4.4 m in Comparative Example 11, 4.4 m in Comparative Example 12, and 4.4 m in Comparative Example 13. Furthermore, the resistance deterioration rate was 167% after 10 times in the comparative example 11, 633% after 100 times, and disconnected after 500 times, and the comparative example 12 was 100% after 10 times, 100% after 100 times, It was 1200% after 500 times, and in Comparative Example 13, it was 100% after 10 times, 100% after 100 times, and 800% after 500 times.

  The conditions and results of these Comparative Examples 11 to 13 are shown in Tables 1 to 3.

  If an inlay (consisting of an IC chip and an antenna) is manufactured by incorporating an RFID tag antenna such as an IC tag antenna formed using the silver conductive film according to the present invention, an IC tag having a practical communication distance can be obtained. FEID tags can be manufactured.

DESCRIPTION OF SYMBOLS 10 Base material 12 Film | membrane 12 'Conductive film 14 Dipole antenna 16 IC chip 18 Adhesive peeling film 20 Sample for bending test 22 Pillar

Claims (9)

30-50 vol% of the sintered body and the RFID tag antenna for vinyl copolymer latex and a polyurethane thickener and a and volume resistivity chloride is formed by the silver conductive film Ru 3~100μΩ · cm der of the silver particles. 2. The RFID tag antenna according to claim 1 , wherein the silver conductive film has a surface resistivity of 0.5Ω / □ or less. The RFID tag antenna according to claim 1 or 2 , wherein the silver conductive film has a thickness of 1 to 6 µm. The silver conductive film according to any one of claims 1 to 3 , wherein a silver particle dispersion containing 50 to 70% by mass of silver particles, a vinyl chloride copolymer latex, and a polyurethane thickener is applied to the substrate and then fired to form the silver conductive film according to any one of claims 1 to 3. An RFID tag antenna manufacturing method, comprising: forming an RFID tag antenna . 5. The RFID tag antenna manufacturing method according to claim 4 , wherein the silver particle dispersion is applied to the substrate by flexographic printing. 5. The method of manufacturing an RFID tag antenna according to claim 4 , wherein the silver particle dispersion is applied to the substrate by repeating flexographic printing a plurality of times. The RFID tag antenna manufacturing method according to claim 4 , wherein the silver particle dispersion is applied to the substrate by repeating flexographic printing 2 to 4 times. Wherein the average particle diameter of the silver particles is 20nm or less, the method of manufacturing the RFID tag antenna according to any one of claims 5 to 7. RFID tag having an antenna for R FID tag according to any one of claims 1 to 3, and an IC chip.

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