JP2013137891A - Silver conductive film and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silver conductive film, in which a silver conductive film exhibiting sufficient conductivity can be mass produced by sintering silver fine particles together even through heat treatment at lower temperatures and for a shorter time than conventional arts.SOLUTION: A silver fine particle dispersion liquid 5 is applied on a base material by flexographic printing and then calcined to form a silver conductive film on the base material, the silver fine particle dispersion liquid 5 including 30-70 mass%, preferably 40-65 mass% of silver fine particles with an average particle size of 1-100 nm dispersed in an aqueous dispersion medium including 50 mass% or more of water, and being added with one kind or more of chlorine compounds selected from the group consisting of sodium chloride, ammonium chloride, potassium chloride and calcium chloride so that a mass ratio (Cl/Ag) of Cl to Ag is 0.05-0.3 mass%.

Description

  The present invention relates to a silver conductive film and a method for manufacturing the same, and more particularly to a silver conductive film used for forming a conductive circuit of an electronic component such as an RFID antenna and a method for manufacturing the same.

  Conventionally, wiring and conductive circuits of electronic components such as RFID antennas that require high reliability are formed on a masked substrate by sputtering of expensive noble metal. However, the method of forming a wiring or a conductive circuit by sputtering requires various steps, so it cannot be said that the productivity is high, and all of the expensive noble metal that is input as a raw material is not the wiring or conductive circuit. Since it is not used for formation, from the viewpoint of effective utilization of resources, formation of wirings and conductive circuits by other methods has been studied.

  In recent years, as a method for easily forming a large amount of wiring and conductive circuits of electronic components, printed electronics that forms wiring and conductive circuits by applying printing technology has attracted attention. After the conductive ink dispersed in the substrate is printed on the substrate by various printing techniques such as flexographic printing and screen printing, it is considered to sinter metal particles to form wiring, conductive circuits, etc. ing.

  On the other hand, when the particle size of the metal particles is several nanometers to several tens of nanometers, the specific surface area becomes very large and the melting point decreases dramatically. Compared to the case where wiring or conductive circuit is formed using dispersed conductive ink, not only fine wiring and conductive circuit can be formed, but also metal particles even when fired at a low temperature of 200 ° C. or lower. Since it becomes possible to sinter each other, various substrates such as a substrate having low heat resistance can be used. For this reason, conductive ink (metal fine particle dispersion) in which metal fine particles (metal nanoparticles) with a particle size of several tens of nanometers or less are dispersed in a dispersion medium is applied to printed electronics to make fine wiring and It is expected to form a conductive circuit.

  In addition, metal fine particles having a particle size of several tens of nanometers or less have very high activity and are unstable as particles as they are, so that sintering and aggregation of metal fine particles are prevented, and the independence and storage of metal fine particles In order to ensure stability, a conductive ink (metal fine particle dispersion) is proposed in which metal fine particles coated with an organic substance such as a long-chain surfactant are dispersed in an organic solvent such as decane or terpineol. However, when metal fine particles are coated with a high-molecular-weight long-chain surfactant, the boiling point and decomposition point thereof are high, so the metal fine particles are sintered together to form a silver conductive film to form wiring and conductive circuits. In order to remove or decompose the surfactant on the surface of the metal fine particles, it is necessary to treat at a high temperature, which makes it impossible to use a substrate having low heat resistance, and about 30 minutes to 1 hour. Therefore, it is necessary to perform heat treatment for a relatively long time, resulting in poor productivity. In addition, if an organic solvent is used as a dispersion medium for the conductive ink, it may cause environmental pollution if care is not taken during disposal, and organic components that have evaporated when heated or left in an open system. Since it diffuses to the surroundings, it is necessary to install a local exhaust device in the case of processing in large quantities. Therefore, if a dispersion medium that does not contain an organic solvent as a main component can be used, it is desirable in terms of environment and work.

  Therefore, a metal nanoparticle composition is proposed in which metal nanoparticles coated with a linear fatty acid having 3 to 8 carbon atoms or a derivative thereof are dispersed in a medium mainly composed of water (for example, see Patent Document 1). . If this metal nanoparticle composition is used, heat treatment at a low temperature for a short time, for example, heat treatment of 140 ° C. or less and less than 90 seconds, the metal nanoparticles are sintered to each other so that a good wiring or conductive circuit is formed on the substrate. Can be formed.

  In addition, a composition containing ultrafine silver particles containing ultrafine silver particles of 0.1 μm or less, a polymer latex, and a water-soluble halide in an aqueous medium has been proposed (see, for example, Patent Document 2). If this silver ultrafine particle containing composition is used, a wiring, a conductive circuit, etc. can be formed on a base material, without requiring a baking process.

Japanese Patent Laying-Open No. 2011-202265 (paragraph numbers 0027-0045) JP2011-159392A (paragraph number 0020)

  However, the metal nanoparticle composition of Patent Document 1 is applied to an inexpensive and low heat resistant substrate such as PET film or paper by a roll-to-roll continuous flexo printing machine that is usually used industrially. When printed and heat-treated, the metal nanoparticles cannot be sufficiently sintered, and it is difficult to obtain good conductivity. In other words, in a roll-to-roll continuous flexo printing machine, in order to increase productivity, it is desired to set the printing speed to 30 m / min or more. Even if the heat treatment furnace attached to the flexographic printing machine is set to 140 ° C. (to sinter the metal nanoparticles of the metal nanoparticle composition of Patent Document 1), the substrate is heated to that temperature. Before the heat treatment furnace. On the other hand, when the set temperature is increased, there is a problem that even if the metal nanoparticles can be fired, the substrate is deformed or burnt by heat. For this reason, the metal nanoparticles cannot be sufficiently sintered, and it is difficult to obtain good conductivity.

  Moreover, since the silver ultrafine particle containing composition of patent document 2 forms the electroconductive pattern by apply | coating on a base material and making it dry without requiring a baking process, it is a roll-to-roll continuous It is difficult to obtain good conductivity by printing on a substrate with a flexographic press of the type.

  Therefore, in view of such conventional problems, the present invention is capable of mass-producing silver conductive films exhibiting sufficient conductivity by sintering silver fine particles with each other even in a heat treatment at a lower temperature and in a shorter time than conventional. An object of the present invention is to provide a method for producing a silver conductive film.

  As a result of diligent research to solve the above problems, the present inventors applied a silver fine particle dispersion in which 30 to 70% by mass of silver fine particles are dispersed in an aqueous dispersion medium and a chlorine compound is added to a substrate. After firing, the silver conductive film is formed on the base material, so that the silver fine particles are sintered even in a heat treatment at a lower temperature and in a shorter time than in the past to produce a large amount of silver conductive film exhibiting sufficient conductivity. As a result, the present invention has been completed.

  That is, in the method for producing a silver conductive film according to the present invention, a silver fine particle dispersion in which 30 to 70% by mass of silver fine particles are dispersed in a water-based dispersion medium and a chlorine compound is added is applied to a substrate and then fired. Thus, a silver conductive film is formed on the substrate.

  In this method for producing a silver conductive film, the chlorine compound is preferably added so that the mass ratio of Cl to Ag (Cl / Ag) is 0.05 to 0.3% by mass. It is preferably at least one selected from the group consisting of ammonium, potassium chloride and calcium chloride. Further, the silver fine particle content in the silver fine particle dispersion is preferably 40 to 65% by mass, and the aqueous dispersion medium is preferably a solvent containing 50% by mass or more of water. Moreover, it is preferable that the average particle diameter of silver fine particles is 1-100 nm, and it is preferable that application | coating to the base material of a silver fine particle dispersion is performed by flexographic printing.

  The RFID antenna manufacturing method according to the present invention is characterized in that, in the silver conductive film manufacturing method, the silver conductive film is formed in the shape of the RFID antenna.

  Furthermore, the silver conductive film according to the present invention contains a sintered body of silver fine particles and chlorine, has a surface resistivity of 0.01 to 1.00 Ω / □ and a volume resistivity of 2.0 to 100.0 μΩ · cm. It is characterized by being.

  In the present specification, “average particle diameter of silver fine particles” refers to an average primary particle diameter (average primary particle diameter) that is an average value of primary particle diameters according to a transmission electron micrograph (TEM image) of silver fine particles. Say.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a silver electrically conductive film which can mass-produce the silver electrically conductive film which sinters silver fine particles even by heat processing for a short time at still lower temperature than conventional, and shows sufficient electroconductivity is provided. can do.

It is a perspective view which shows schematically the flexoproof used in order to apply | coat to a base material the silver fine particle dispersion liquid produced in the Example and the comparative example. 1B is a side view of the flexoproof of FIG. 1A. FIG. It is a top view which shows the shape of the RFID antenna produced by the Example and the comparative example. It is a perspective view of the IC chip mounting RFID antenna produced by the Example and the comparative example. 3B is a side view of the IC chip mounted RFID antenna of FIG. 3A. FIG.

  In the embodiment of the method for producing a silver conductive film according to the present invention, a silver fine particle dispersion in which 30 to 70% by mass of silver fine particles are dispersed in an aqueous dispersion medium and a chlorine compound is added is applied to a substrate and then fired. Then, a silver conductive film is formed on the substrate. In addition, it is preferable that application | coating to the base material of a silver fine particle dispersion is performed by flexographic printing.

  The aqueous dispersion medium is a solvent containing water as a main component, and is preferably a solvent containing 50% by mass or more, more preferably 75% by mass or more. In order to adjust the viscosity of the aqueous dispersion medium, a thickener (thickener) such as polyurethane thickener of 10% by mass or less may be added to the silver fine particle dispersion, and 10% by mass or less for wetting. An organic solvent such as propylene glycol may be added. In order to further strengthen the adhesion between the aqueous dispersion medium and the substrate, an aqueous dispersion resin in which a polymer is stably suspended and dispersed in water may be added. As this aqueous dispersion resin, aqueous latex such as vinyl chloride can be used. The addition amount of the aqueous dispersion resin is preferably 0.5 to 8% by mass, and more preferably 1 to 7% by mass. If it is less than 0.5% by mass, it is not sufficient to further strengthen the adhesion to the substrate, and if it exceeds 8% by mass, the dispersibility deteriorates, for example, aggregates are generated in the silver fine particle dispersion. At the same time, it adversely affects the conductivity when forming a coating film, which is not preferable.

  As chlorine compounds, oxoacids such as hypochlorous acid, sodium chlorite, potassium chlorite, sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, etc., hydrogen such as hydrochloric acid Inorganic salts such as chemical compounds, lithium salts, sodium salts, potassium salts, barium salts, strontium salts, ammonium salts, zirconium salts, aluminum salts, magnesium salts, calcium salts, and the like can be used. Among these, it is preferable to use one or more chlorine compounds selected from the group consisting of sodium chloride, ammonium chloride, potassium chloride, and calcium chloride. It is preferable to add such a chlorine compound so that the mass ratio of Cl to Ag (Cl / Ag) is 0.05 to 0.3 mass%.

  The silver fine particles have an average particle diameter of 1 to 100 nm, preferably 1 to 50 nm, more preferably 1 to 30 nm, and most preferably 1 to 20 nm. When the average particle size is larger than 100 nm, it is difficult to obtain the low-temperature sinterability expected as silver fine particles. Further, the content of the silver fine particles in the silver fine particle dispersion is 30 to 70% by mass, and preferably 40 to 65% by mass. Moreover, it is preferable that the surface of the silver fine particles is coated with a linear fatty acid having 3 to 8 carbon atoms or a derivative thereof. Such a coating prevents sintering between the silver fine particles and keeps the distance between the silver fine particles moderate. If the carbon number is greater than 8, high thermal energy is required during pyrolysis. On the other hand, if the carbon number is smaller than 3, the distance between the silver fine particles cannot be maintained appropriately.

  The average particle diameter (primary particle average diameter) of the silver fine particles is, for example, 60% by mass of Ag particles, 3.0% by mass of vinyl chloride copolymer latex, 2.0% by mass of polyurethane thickener, and 2.5% by mass. Obtained by adding 2 parts by mass of an aqueous Ag ink containing silver fine particles such as an aqueous Ag ink containing propylene glycol to a mixed solution of 96 parts by mass of cyclohexane and 2 parts by mass of oleic acid and dispersing by ultrasonic waves. The dispersion solution is dropped onto a Cu microgrid with a support film and dried, and the silver fine particles on the microgrid are brightened at an accelerating voltage of 100 kV with a transmission electron microscope (JEM-100CXMark-II type manufactured by JEOL Ltd.) in a bright field. The observed image can be taken at a magnification of 300,000 and calculated from the obtained TEM image. The primary particle average diameter of the silver fine 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.

  According to the embodiment of the method for producing a silver conductive film described above, the sintered body of silver fine particles and chlorine are included, the surface resistivity is 0.01 to 1.00 Ω / □, and the volume resistivity is 2.0 to 100. A silver conductive film having a thickness of 0.0 μΩ · cm can be produced.

  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, Aqueous Ag ink (PFI-700, manufactured by P-Chem Associates, Inc.) containing water is separated into a supernatant and Ag particles by centrifugation (at 3000 rpm for 10 minutes), and then the precipitated Ag particles are not entrained The supernatant liquid was separated into a concentrated Ag ink having an Ag concentration of 71.49% by mass.

  Moreover, 25 g of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 75 g of pure water to prepare a 25% by mass sodium chloride aqueous solution.

  Next, 0.25 g (Example 1), 0.18 g (Example 2), 0.09 g (Example 3), and 0.05 g (Example 3) of the above sodium chloride solution were added to 19.5 g of the concentrated Ag ink. Example 4) After the addition, the above supernatant (sorted supernatant) was added so that the Ag concentration was 65% by mass, and the Ag concentration was 65% by mass and the ratio of the mass of Cl to Ag ( Cl / Ag) of 0.30% by mass (Example 1), 0.20% by mass (Example 2), 0.10% by mass (Example 3) and 0.05% by mass (Example 4), respectively. A silver fine particle dispersion was prepared.

  The silver fine particle dispersion liquid of each Example produced in this manner was used with a flexo-proof (model ESI12, anilox, 200 line, manufactured by RK Print Court Instruments) schematically shown in FIGS. 1A and 1B. Base material A made of polyethylene terephthalate (PET) film (Melinex (registered trademark) 545 manufactured by Dupontidine Film Co.), base material B made of coated paper (DF-110GN manufactured by Mitsubishi Paper Industries Co., Ltd.), and cast coat Each of the three substrates was coated on a substrate C made of paper (Miracoat manufactured by Oji Paper Co., Ltd.).

  As shown in FIGS. 1A and 1B, the flexoproof 1 includes a cylindrical rubber plate 2, a cylindrical anilox roller 3 disposed above the rubber plate 2, and the anilox roller 3. And a doctor blade 4 attached thereto. The distance between the rubber plate 2 and the anilox roller 3 and the distance between the doctor blade 4 and the anilox roller 3 can be adjusted. When the rubber plate 2 is pressed onto the substrate 7 and pulled in the direction of arrow A, the rubber plate 2 rotates in the direction of arrow B, and the anilox roller 3 rotates reversely in the direction of arrow C along with the rotation. In this flexoproof 1, the paint (silver fine particle dispersion) 5 dripped between the doctor blade 4 and the anilox roller 3 has a constant film thickness between the rotating anilox roller 3 and the doctor blade 4. After being transferred to the rubber plate 2 at the contact surface with the rubber plate 2, the rubber plate 2 is conveyed to the base material 7 by the rotation of the rubber plate 2 and transferred onto the base material 7. A coating film 6 is formed thereon. By operating the adjustment knobs at both ends of such a flexoproof and pushing it further from the position where the rubber plate and the anilox roller contact each other by 0.05 to 0.10 mm, about 1 mL is inserted between the doctor blade and the anilox roller. The silver fine particle dispersion was dropped, and the silver fine particle dispersion was applied onto the substrate in about 1 second.

  Immediately after applying the silver fine particle dispersion in this way, a silver conductive film was produced by baking at 60 ° C. for 15 seconds on a hot plate. In order to maintain good contact between the base material and the hot plate during firing, the unprinted portion of the base material is first pressed against the hot plate, and the firing proceeds and the silver fine particle dispersion is transferred to Bencot. After the disappearance, firing was performed so that the entire base material was pressed against the hot plate by Bencott.

  Next, the produced silver conductive film was cut into a size of 3 cm × 3 cm, and the surface resistance of the silver conductive film was measured by a four-terminal method using a surface resistivity meter (Lorestar GP manufactured by Mitsubishi Chemical Analytic Co., Ltd.). The rate (sheet resistivity) was measured. As a result, the surface resistivity of the silver conductive film was 0.12 Ω / □ (base material A), 0.14 Ω / □ (base material B), 0.21 Ω / □ (base material C) in Example 1, respectively. In Example 2, 0.07Ω / □ (base material A), 0.11Ω / □ (base material B), 0.10Ω / □ (base material C), and in Example 3, 0.07Ω / □ (base), respectively. Material A), 0.13Ω / □ (base material B), 0.11Ω / □ (base material C), and in Example 4, 0.06Ω / □ (base material A) and 0.31Ω / □ (base material), respectively. B), 0.25Ω / □ (base material C).

  Moreover, about the silver electrically conductive film formed on the base material A, the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed.

  As for the film thickness of the silver conductive film, the difference in height between the surface of the base material A on which the silver conductive film was formed and the surface of the silver conductive film was measured at 100 locations using a laser microscope (model VK-9700 manufactured by KEYENCE). It was determined by measuring and calculating the average value. As a result, the film thickness of the silver conductive film was 1.73 μm in Example 1, 1.82 μm in Example 2, 1.76 μm in Example 3, and 1.80 μm in Example 4.

  The volume resistivity of the silver conductive film was determined from the film thickness, electrical resistance, and area (3.0 cm × 3.0 cm) of the silver conductive film. As a result, the volume resistivity of the silver conductive film was 20.8 μΩ · cm in Example 1, 12.7 μΩ · cm in Example 2, 13.0 μΩ · cm in Example 3, 11.3 μΩ · cm in Example 4. cm.

The ratio of the metal (Ag) in the conductive film was determined by dissolving a silver conductive film having a printed area of 3.0 cm × 3.0 cm in a concentrated nitric acid solution (of a known weight), and determining the Ag concentration in the solution from ICP emission spectrometry. seeking, after calculating the weight (g) of Ag in the conductive silver film portions to determine Ag volume (cm ³⁾ from the density of 10.5 g / cm ³ of Ag, the film thickness of the conductive film and the printing area (3 0.0 cm × 3.0 cm), the volume of the silver conductive film was determined, and calculated from the volume of Ag (cm ³ ) × 100 / the volume of the silver conductive film (cm ³ ). As a result, the ratio of Ag in the conductive film was 31.5% by volume in Example 1, 30.0% by volume in Example 2, 31.0% by volume in Example 3, and 30.3% by volume in Example 4. %Met.

[Comparative Example 1]
The above supernatant (sorted supernatant) was added to 19.5 g of the concentrated Ag ink prepared in Example 1 so that the Ag concentration was 65% by mass, and the Ag concentration was 65% by mass with respect to Ag. A silver fine particle dispersion having a mass ratio of Cl (Cl / Ag) of 0.00 mass% was produced, and a silver conductive film was produced in the same manner as in Example 1. Thus, when the surface resistivity of the produced silver electrically conductive film was measured by the method similar to Example 1, 0.30 ohm / square (base material A), 1.50 ohm / square (base material B), It was 0.61Ω / □ (base material C). Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was 1. 0.83 μm, the volume resistivity was 54.9 μΩ · cm, and the ratio of Ag in the silver conductive film was 29.8% by volume.

[Comparative Example 2]
After adding 0.46 g of the sodium chloride solution prepared in Example 1 to 19.5 g of the concentrated Ag ink prepared in Example 1, the supernatant collected in Example 1 so that the Ag concentration is 65% by mass. The solution was added to prepare a silver fine particle dispersion having an Ag concentration of 65% by mass and a ratio of Cl to Ag (Cl / Ag) of 0.50% by mass. In this comparative example, a phenomenon that seems to be sintering of Ag particles occurred a few minutes after the sodium chloride solution was added to the concentrated Ag ink, and a solid material without fluidity was formed. could not.

[Examples 5 to 8]
The sodium chloride solution prepared in Example 1 was added to 18.0 g of the concentrated Ag ink prepared in Example 1 and 0.25 g (Example 5), 0.17 g (Example 6), and 0.08 g (Example 7), respectively. ), 0.04 g (Example 8) was added, and then the above supernatant (sorted supernatant) was added so that the Ag concentration was 60% by mass, and the Ag concentration was 60% by mass relative to Ag. The mass ratio of Cl (Cl / Ag) was 0.30 mass% (Example 5), 0.20 mass% (Example 6), 0.10 mass% (Example 7), and 0.05 mass%, respectively. A silver fine particle dispersion of (Example 8) was prepared, and a silver conductive film was prepared by the same method as in Example 1.

  The surface resistivity of the silver conductive film thus prepared was measured by the same method as in Example 1. In Example 5, 0.18 Ω / □ (base material A) and 0.21 Ω / □ (base), respectively. Material B), 0.22 Ω / □ (base material C), and in Example 6, 0.11 Ω / □ (base material A), 0.27 Ω / □ (base material B), 0.19 Ω / □ (base material) C), in Example 7, 0.12 Ω / □ (base material A), 0.25 Ω / □ (base material B), 0.25 Ω / □ (base material C), and in Example 8, 0.12 Ω / □, respectively. □ (base material A), 0.32 Ω / □ (base material B), and 0.28 Ω / □ (base material C).

  Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was each 1.59 μm (Example 5), 1.63 μm (Example 6), 1.58 μm (Example 7), 1.60 μm (Example 8), and the volume resistivity is 28.6 μΩ · cm (implemented). Example 5), 17.9 μΩ · cm (Example 6), 19.0 μΩ · cm (Example 7), 19.2 μΩ · cm (Example 8), and the ratio of Ag in the silver conductive film was 24, respectively. They were 0.8 volume% (Example 5), 24.2 volume% (Example 6), 24.8 volume% (Example 7), and 25.6 volume% (Example 8).

In addition, flexographic printing machines (JEM Flex, a multi-purpose fine printing machine manufactured by JEOL Seiki Co., Ltd.) and flexographic printing plates (manufactured by Gosando Watanabe, printing plate made of Asahi Kasei's plate-like photosensitive resin AWP) Grade DEF, surface treatment 150 lines, 96 DOT%), anilox capacity 20 cc / m ² (150 lines / inch), printing speed 20 m / min, printing frequency 1 time, polyethylene terephthalate (PET) film (Dupontidine) Two types of base materials (in FIGS. 3A and 3B), a base material A composed of Melinex (registered trademark) 545 manufactured by Film Co., Ltd. and a base material B composed of coated paper (DF-110GN manufactured by Mitsubishi Paper Industries Co., Ltd.) Each of the silver fine particle dispersions obtained in Examples 5 and 7 was formed in each of the shapes shown in FIG. After printing on the shape of the RFID antenna 10 having a width of 18.5 mm and a line width of 0.7 mm, an RFID antenna made of a silver conductive film was manufactured by heat treatment on a hot plate at 140 ° C. for 30 seconds and firing.

  When the line resistance (electric resistance between D and E shown in FIG. 2) of this silver conductive film was measured by a tester (model CDM-03D manufactured by CUSTOM), in Example 5, 43.7Ω (base material A ), 33.2Ω (base material B), and in Example 7, they were 31.0Ω (base material A) and 28.7Ω (base material B), respectively.

  Further, an anisotropic conductive adhesive (ACP) (TAP0604C (Au / Ni coated polymer particles) manufactured by Kyocera Chemical Co., Ltd.) is thinly applied to the IC chip mounting portion 11 of these RFID antennas 10, and an IC is formed on the ACP. After placing the chip (Monza 2 manufactured by Impinj) 12 and applying pressure of 1.0 N at a temperature of 160 ° C. for 10 seconds with a thermocompression bonding apparatus (TTS300 manufactured by Mühlbauer), the IC chip is attached to the RFID antenna 10. By fixing and connecting 12, the IC chip 12 was mounted on the RFID antenna 10 as shown in FIGS. 3A and 3B.

  With respect to the IC chip mounted RFID antenna thus manufactured, in a anechoic box (MY1530 made by Micronics), a communication distance measuring device (tagformance made by Voyantic) was used, and a frequency region (ISO / ISO) of 800 MHz to 1100 MHz was used. The communication distance (theoretical read range forward) of the IEC 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 is 1.6 m (base material A) and 1.4 m (base material B) in Example 5, and 1.6 m (base material A) and 1 in Example 7, respectively. .6 m (Base B).

  In addition, as a weather resistance test, the RFID antenna made of the silver conductive film obtained in Examples 5 and 7 and the IC chip mounted RFID antenna were left in a constant temperature and humidity chamber set at a temperature of 85 ° C. and a humidity of 85%, respectively, for 500 hours. After (holding), the line resistance of the silver conductive film and the communication distance of the IC chip mounted RFID antenna were measured. As a result, the line resistances of the silver conductive film were 46.4Ω (base material A) and 35.1Ω (base material B) in Example 5, respectively, and 30.1Ω (base material A) in Example 7 respectively. It was 32.7Ω (base material B). Further, the communication distance of the frequency 955 MHz of the IC chip mounted RFID antenna is 1.5 m (base material A) and 1.4 m (base material B) in Example 5, respectively, and 1.6 m (base material) in Example 7. Material A) and 1.5 m (base material B).

[Comparative Example 3]
The above supernatant (sorted supernatant) is added to 18.0 g of the concentrated Ag ink prepared in Example 1 so that the Ag concentration is 60% by mass, and the Ag concentration is 60% by mass with respect to Ag. A silver fine particle dispersion having a mass ratio of Cl (Cl / Ag) of 0.00 mass% was produced, and a silver conductive film was produced in the same manner as in Example 1. Thus, when the surface resistivity of the produced silver electrically conductive film was measured by the method similar to Example 1, 0.36 ohm / square (base material A), 2.20 ohm / square (base material B), It was 0.83Ω / □ (base material C). Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was 1. The volume resistivity was 58.7 μΩ · cm, and the Ag ratio in the silver conductive film was 25.2% by volume.

  Further, an RFID antenna made of a silver conductive film and an IC chip-mounted RFID antenna were prepared by the same method as in Examples 5 and 7, and the line resistance of the silver conductive film and the communication distance of the IC chip-mounted RFID antenna were measured. As a result, the line resistance of the silver conductive film is 30.8Ω (base material A) and 28.5Ω (base material B), respectively, and the communication distance of the frequency 955 MHz of the IC chip mounted RFID antenna is 1.6 m (each Base material A) and 1.5 m (base material B).

  In addition, after the RFID antenna made of the silver conductive film and the IC chip mounted RFID antenna are left (held) in a thermo-hygrostat for 500 hours, the line resistance of the silver conductive film and the communication distance of the IC chip mounted RFID antenna are set. It was measured. As a result, the line resistance of the silver conductive film is 29.2Ω (base material A) and 29.5Ω (base material B), respectively, and the communication distance of the frequency 955 MHz of the IC chip mounted RFID antenna is 1.5 m (each Base material A) and 1.5 m (base material B).

[Comparative Example 4]
After adding 0.42 g of the sodium chloride solution prepared in Example 1 to 18.0 g of the concentrated Ag ink prepared in Example 1, the supernatant fractionated in Example 1 so that the Ag concentration is 60% by mass. The solution was added to prepare a silver fine particle dispersion having an Ag concentration of 60% by mass and a ratio of Cl to Ag (Cl / Ag) of 0.50% by mass. In this comparative example, a phenomenon that seems to be sintering of Ag particles occurred a few minutes after the sodium chloride solution was added to the concentrated Ag ink, and a solid material without fluidity was formed. could not.

[Examples 9 to 11]
25 g of ammonium chloride (NH ₄ Cl) (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 75 g of pure water to prepare a 25 mass% ammonium chloride aqueous solution (Example 9), potassium chloride (KCl) (Wako Pure Chemical Industries, Ltd.) 25 g of 25% by weight potassium chloride aqueous solution (Example 10) and calcium chloride (CaCl ₂ ) (manufactured by Wako Pure Chemical Industries, Ltd.) 25 g are dissolved in 75 g of pure water. % Calcium chloride aqueous solution (Example 11) was prepared.

  Next, 18.0 g of the concentrated Ag ink prepared in Example 1 was added to the above ammonium chloride solution 0.16 g (Example 9), potassium chloride solution 0.22 g (Example 10), and calcium chloride solution 0.16 g ( After each of Example 11) was added, the above supernatant (sorted supernatant) was added so that the Ag concentration was 60% by mass, and the Ag concentration was 60% by mass and the mass of Cl relative to Ag. A silver fine particle dispersion having a ratio (Cl / Ag) of 0.20% by mass was produced, and a silver conductive film was produced in the same manner as in Example 1.

  When the surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1, in Example 9, 0.11Ω / □ (base material A) and 0.26Ω / □ (base), respectively. Material B), 0.19Ω / □ (base material C), and in Example 10, 0.12Ω / □ (base material A), 0.28Ω / □ (base material B), 0.21Ω / □ (base material), respectively. C) and Example 11 were 0.12 Ω / □ (base material A), 0.37 Ω / □ (base material B), and 0.21 Ω / □ (base material C), respectively.

  Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was each 1.66 μm (Example 9), 1.70 μm (Example 10), 1.73 μm (Example 11), and the volume resistivity is 18.3 μΩ · cm (Example 9) and 20.4 μΩ · cm, respectively. (Example 10) It is 20.8 microhm * cm (Example 11), and the ratio of Ag in a silver electrically conductive film is 23.8 volume% (Example 9) and 23.2 volume% (Example 10), respectively. 22.8% by volume (Example 11).

[Examples 12 to 15]
0.21 g (Example 12), 0.14 g (Example 13), and 0.07 g (Example 14) of the sodium chloride solution prepared in Example 1 were added to 15.0 g of the concentrated Ag ink prepared in Example 1. ), 0.04 g (Example 15) was added, and then the above supernatant (sorted supernatant) was added so that the Ag concentration was 50% by mass, and the Ag concentration was 50% by mass relative to Ag. The mass ratio of Cl (Cl / Ag) was 0.30 mass% (Example 12), 0.20 mass% (Example 13), 0.10 mass% (Example 14), and 0.05 mass%, respectively. A silver fine particle dispersion of (Example 15) was prepared, and a silver conductive film was prepared by the same method as in Example 1.

  When the surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1, in Example 12, 0.30Ω / □ (base material A) and 0.43Ω / □ (base), respectively. Material B), 0.47Ω / □ (base material C), and in Example 13, 0.21Ω / □ (base material A), 0.29Ω / □ (base material B), 0.33Ω / □ (base material) C), Example 14 is 0.21 Ω / □ (base material A), 0.44 Ω / □ (base material B), 0.40 Ω / □ (base material C), and Example 15 is 0.24 Ω / □. □ (base material A), 0.65 Ω / □ (base material B), and 0.52 Ω / □ (base material C).

  Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was each It is 1.33 μm (Example 12), 1.28 μm (Example 13), 1.22 μm (Example 14), 1.26 μm (Example 15), and the volume resistivity is 39.9 μΩ · cm (implementation). Example 12), 26.9 μΩ · cm (Example 13), 25.6 μΩ · cm (Example 14), 30.2 μΩ · cm (Example 15), and the ratio of Ag in the silver conductive film was 20 respectively. It was 1% by volume (Example 12), 20.9% by volume (Example 13), 21.9% by volume (Example 14), and 21.2% by volume (Example 15).

[Comparative Example 5]
The above supernatant liquid (prepared supernatant liquid) is added to 15.0 g of the concentrated Ag ink prepared in Example 1 so that the Ag concentration is 50% by mass, and the Ag concentration is 50% by mass with respect to Ag. A silver fine particle dispersion having a mass ratio of Cl (Cl / Ag) of 0.00 mass% was produced, and a silver conductive film was produced in the same manner as in Example 1. When the surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1, 0.56Ω / □ (base material A), 8.60Ω / □ (base material B), It was 1.70Ω / □ (base material C). Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was 1. .32 μm, the volume resistivity was 73.9 μΩ · cm, and the ratio of Ag in the silver conductive film was 20.3% by volume.

[Comparative Example 6]
After adding 0.35 g of the sodium chloride solution prepared in Example 1 to 15.0 g of the concentrated Ag ink prepared in Example 1, the supernatant collected in Example 1 so that the Ag concentration is 50% by mass. The solution was added to prepare a silver fine particle dispersion having an Ag concentration of 50 mass% and a mass ratio of Cl to Ag (Cl / Ag) of 0.50 mass%. In this comparative example, a phenomenon that seems to be sintering of Ag particles occurred a few minutes after the sodium chloride solution was added to the concentrated Ag ink, and a solid material without fluidity was formed. could not.

[Examples 16 to 19]
0.17 g (Example 16), 0.11 g (Example 17), and 0.06 g (Example 18) of the sodium chloride solution prepared in Example 1 were added to 12.0 g of the concentrated Ag ink prepared in Example 1, respectively. ), 0.03 g (Example 19) was added, and then the above supernatant (sorted supernatant) was added so that the Ag concentration was 40% by mass, and the Ag concentration was 40% by mass relative to Ag. The mass ratio of Cl (Cl / Ag) was 0.30 mass% (Example 16), 0.20 mass% (Example 17), 0.10 mass% (Example 18), and 0.05 mass%, respectively. A silver fine particle dispersion of (Example 19) was prepared, and a silver conductive film was prepared by the same method as in Example 1.

  When the surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1, in Example 16, 0.75Ω / □ (base material A) and 0.70Ω / □ (base), respectively. Material B), 0.74Ω / □ (base material C), and in Example 17, 0.80Ω / □ (base material A), 0.62Ω / □ (base material B), 0.40Ω / □ (base material), respectively. C), Example 18 is 0.78 Ω / □ (base material A), 0.60 Ω / □ (base material B), 0.50 Ω / □ (base material C), and Example 19 is 0.86 Ω / □. □ (base material A), 0.96 Ω / □ (base material B), and 0.73 Ω / □ (base material C).

  Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was each 1.20 μm (Example 16), 1.16 μm (Example 17), 1.13 μm (Example 18), 1.15 μm (Example 19), and the volume resistivity is 90.0 μΩ · cm (implementation) Example 16), 92.8 μΩ · cm (Example 17), 88.1 μΩ · cm (Example 18), and 98.9 μΩ · cm (Example 19), and the ratio of Ag in the silver conductive film was 16 respectively. And 37.0% by volume (Example 16), 16.8% by volume (Example 17), 17.3% by volume (Example 18), and 17.0% by volume (Example 19).

[Comparative Example 7]
The above supernatant liquid (prepared supernatant liquid) is added to 12.0 g of the concentrated Ag ink prepared in Example 1 so that the Ag concentration is 40% by mass, and the Ag concentration is 40% by mass with respect to Ag. A silver fine particle dispersion having a mass ratio of Cl (Cl / Ag) of 0.00 mass% was produced, and a silver conductive film was produced in the same manner as in Example 1. The surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1, and was found to be 13.00 Ω / □ (Substrate A) and 14.00 Ω /

□ (base material B), 2.00Ω / □ (base material C). Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was 1. .20 μm, the volume resistivity was 1560.0 μΩ · cm, and the ratio of Ag in the silver conductive film was 16.3 vol%.

[Comparative Example 8]
After adding 0.28 g of the sodium chloride solution prepared in Example 1 to 12.0 g of the concentrated Ag ink prepared in Example 1, the supernatant collected in Example 1 so that the Ag concentration is 40% by mass. The solution was added to prepare a silver fine particle dispersion having an Ag concentration of 40% by mass and a ratio of Cl to Ag (Cl / Ag) of 0.50% by mass. In this comparative example, a phenomenon that seems to be sintering of Ag particles occurred a few minutes after the sodium chloride solution was added to the concentrated Ag ink, and a solid material without fluidity was formed. could not.

[Comparative Examples 9-12]
0.08 g (Comparative Example 9), 0.06 g (Comparative Example 10), and 0.03 g (Comparative Example 11) of the sodium chloride solution prepared in Example 1 were added to 6.0 g of the concentrated Ag ink prepared in Example 1. ), 0.01 g (Comparative Example 12) was added, and then the above supernatant (sorted supernatant) was added so that the Ag concentration was 20% by mass, and the Ag concentration was 20% by mass relative to Ag. The mass ratio of Cl (Cl / Ag) was 0.30 mass% (Comparative Example 9), 0.20 mass% (Comparative Example 10), 0.10 mass% (Comparative Example 11), and 0.05 mass%, respectively. A silver fine particle dispersion of (Comparative Example 12) was prepared, and a silver conductive film was prepared by the same method as in Example 1.

  The surface resistivity of the silver conductive film thus produced was measured by the same method as in Example 1. As a result, in Comparative Example 9, measurement was impossible due to overload (OL) (base material A), 30.0Ω / □ (base material B), 13.0Ω / □ (base material C), and in Comparative Example 10, measurement is not possible due to overload (OL) (base material A), 30.0Ω / □ (base material B), 9. In 4Ω / □ (base material C), in Comparative Example 11, measurement is not possible due to overload (OL) (base material A), 20.0Ω / □ (base material B), 21.0Ω / □ (base material C), In Comparative Example 12, the measurement was impossible due to overload (OL) (base material A), 720.0Ω / □ (base material B), and 47.0Ω / □ (base material C).

  Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was each 0.68 μm (Comparative Example 9), 0.73 μm (Comparative Example 10), 0.75 μm (Comparative Example 11), 0.76 μm (Comparative Example 12), and the volume resistivity is overload (OL). Measurement is impossible, and the proportion of Ag in the silver conductive film is 6.5% by volume (Comparative Example 9), 6.0% by volume (Comparative Example 10), 5.9% by volume (Comparative Example 11), respectively. It was 8 volume% (Comparative Example 12).

[Comparative Example 13]
The above supernatant (sorted supernatant) is added to 6.0 g of concentrated Ag ink prepared in Example 1 so that the Ag concentration is 20% by mass, and the Ag concentration is 20% by mass with respect to Ag. A silver fine particle dispersion having a mass ratio of Cl (Cl / Ag) of 0.00 mass% was produced, and a silver conductive film was produced in the same manner as in Example 1. When the surface resistivity of the silver conductive film thus prepared was measured by the same method as in Example 1, it was impossible to measure with the overload (OL) (base material A) and impossible to measure with the overload (OL). (Base material B) and 150.0Ω / □ (Base material C). Moreover, about the silver electrically conductive film formed on the base material A, when the film thickness, volume resistivity, and the ratio of the metal (Ag) in a silver electrically conductive film were computed by the method similar to Example 1, the film thickness was 0. 0.83 μm, volume resistivity was not measurable due to overload (OL), and the ratio of Ag in the silver conductive film was 5.3% by volume.

  The production conditions and surface resistivity measurement results of the silver conductive films of the examples and comparative examples are shown in Table 1, and the film thickness of the silver conductive films of the examples and comparative examples, the ratio of Ag in the films, and the calculation of the volume resistivity The results are shown in Table 2, and the measurement results of the line resistance of the RFID antenna made of the silver conductive film of Examples 5 and 7 and Comparative Example 3 and the communication distance of the IC chip mounted RFID antenna are shown in Table 3.

  As can be seen from Tables 1 and 2, if a small amount of Cl is added to the silver fine particle dispersion, a silver conductive film exhibiting sufficient conductivity can be obtained even at a low temperature for a short time. In addition, as can be seen from Table 3, even when a small amount of Cl is added to the silver fine particle dispersion to produce an RFID antenna made of a silver conductive film or an IC chip mounted RFID antenna, the conductivity and communication distance are affected. Absent.

  The silver fine particle dispersion according to the present invention can be applied to printed electronics, for example, printing CPU, printing illumination, printing tag, all printing display, sensor, printed wiring board, organic solar cell, electronic book, nanoimprint LED. It can be used for manufacturing liquid crystal display panels, plasma display panels, print memories, and the like.

1 Flexoproof 2 Rubber plate 3 Anilox roller 4 Doctor blade 5 Paint (silver fine particle dispersion)
6 Coating 7 Base material 10 RFID antenna 11 IC chip mounting part 12 IC chip 13 Base material

Claims (9)

A silver fine particle dispersion in which 30 to 70% by mass of silver fine particles are dispersed in an aqueous dispersion medium and a chlorine compound is added is applied to the base material and then baked to form a silver conductive film on the base material. The manufacturing method of a silver electrically conductive film. 2. The silver conductive film according to claim 1, wherein the chlorine compound is added so that a mass ratio of Cl to Ag (Cl / Ag) is 0.05 to 0.3 mass%. Production method. The method for producing a silver conductive film according to claim 1 or 2, wherein the chlorine compound is at least one selected from the group consisting of sodium chloride, ammonium chloride, potassium chloride, and calcium chloride. The method for producing a silver conductive film according to any one of claims 1 to 3, wherein a content of silver fine particles in the silver fine particle dispersion is 40 to 65 mass%. The method for producing a silver conductive film according to claim 1, wherein the aqueous dispersion medium is a solvent containing 50% by mass or more of water. 6. The method for producing a silver conductive film according to claim 1, wherein the silver fine particles have an average particle diameter of 1 to 100 nm. The method for producing a silver conductive film according to any one of claims 1 to 6, wherein the silver fine particle dispersion is applied to a base material by flexographic printing. 8. The method of manufacturing an RFID antenna according to claim 1, wherein the silver conductive film is formed in the shape of an RFID antenna. Silver conductive material comprising a sintered body of silver fine particles and chlorine, having a surface resistivity of 0.01 to 1.00 Ω / □ and a volume resistivity of 2.0 to 100.0 μΩ · cm. film.

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