WO2019188293A1 - Conductive film forming agent - Google Patents

Conductive film forming agent Download PDF

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Publication number
WO2019188293A1
WO2019188293A1 PCT/JP2019/010278 JP2019010278W WO2019188293A1 WO 2019188293 A1 WO2019188293 A1 WO 2019188293A1 JP 2019010278 W JP2019010278 W JP 2019010278W WO 2019188293 A1 WO2019188293 A1 WO 2019188293A1
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WO
WIPO (PCT)
Prior art keywords
conductive film
film forming
forming agent
powder
cellulose
Prior art date
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PCT/JP2019/010278
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French (fr)
Japanese (ja)
Inventor
汰玖哉 吉岡
Original Assignee
第一工業製薬株式会社
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Publication of WO2019188293A1 publication Critical patent/WO2019188293A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D101/00—Coating compositions based on cellulose, modified cellulose, or cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/24—Electrically-conducting paints
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
    • C09D7/40—Additives
    • C09D7/60—Additives non-macromolecular
    • C09D7/61—Additives non-macromolecular inorganic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B5/00—Non-insulated conductors or conductive bodies characterised by their form
    • H01B5/14—Non-insulated conductors or conductive bodies characterised by their form comprising conductive layers or films on insulating-supports

Definitions

  • the present invention relates to a conductive film forming agent and a conductive film formed using the same.
  • Patent Document 1 as a conductive film forming agent suitable for the ink jet method, alkanes having 8 or less carbon atoms, isoparaffins and / or liquid paraffin, and metal nanoparticles having a particle diameter of 100 nm or less made of metal and organic matter, Metal nanoparticle dispersions containing are disclosed.
  • Patent Document 1 good coating properties are obtained by containing a specific alkane.
  • the metal nanoparticles used have a small particle diameter of 100 nm or less, the surface energy becomes very large and aggregation tends to occur. There is a concern that the storage stability of the metal nanoparticle dispersion is lowered.
  • Patent Document 2 discloses an inorganic particle film forming agent that is suitable for the spray method and has good storage stability. Patent Document 2 discloses that an inorganic particle film forming agent excellent in sprayability and storage stability can be obtained by containing an aqueous dispersion of cellulose fibers and water as a dispersion medium.
  • silver powder As a metal powder (that is, conductive powder), but silver powder is generally surface-treated with a fatty acid as a hydrophobic treatment at the time of production. Since the affinity with water is low, it is difficult to apply to a technique using water as a dispersion medium as described in Patent Document 2.
  • Embodiment of this invention aims at providing the electrically conductive film formation agent which can form the electrically conductive film which is excellent in coating-film formation property, such as sprayability, and storage stability, and favorable electroconductivity.
  • the conductive film forming agent according to the embodiment of the present invention contains the following components (A) to (C).
  • the conductive film forming agent according to the embodiment of the present invention When the conductive film forming agent according to the embodiment of the present invention is used, it is possible to form a conductive film having excellent conductivity while being excellent in coating film forming properties such as sprayability and storage stability.
  • the conductive film forming agent according to the present embodiment contains (A) silver powder and / or silver-coated powder, (B) cellulose nanofiber, and (C) an organic solvent, and the organic solvent is used as a dispersion medium.
  • silver powder and / or silver-coated powder can be used as the metal powder, and therefore, good conductivity can be imparted.
  • thixotropy thixotropy
  • the component (A) one or both of silver powder (that is, silver powder) and silver coat powder is used.
  • the specific structure of silver powder and / or silver coat powder is not specifically limited,
  • the various silver powder and silver coat powder which are generally used for the electrically conductive film formation agent can be used.
  • the shape is not particularly limited, and examples thereof include various shapes such as a spherical shape and a flake shape, but a flake shape is preferable because the specific resistance is lowered.
  • Silver coated powder is powder coated with silver on the surface, for example, silver coated metal powder such as silver coated copper powder, silver coated nickel powder, silver coated aluminum powder, silver coated glass powder, silver coated resin powder, etc. Is mentioned.
  • a hydrophobic treatment for example, a surface treated with a fatty acid may be used.
  • the particle diameter of the silver powder and / or silver coat powder of the component (A) is not particularly limited, but from the viewpoint of imparting excellent conductivity, the 50% average particle diameter (D50) is 100 nm or more, that is, 0.1 ⁇ m or more. Some are preferred. D50 may be 0.1 to 20 ⁇ m, 1 to 10 ⁇ m, or 2 to 5 ⁇ m.
  • D50 can be measured by a laser diffraction method. For example, 0.3 g of metal powder is weighed into a 50 ml beaker, 30 ml of isopropyl alcohol is added, and then dispersed by treatment with an ultrasonic cleaner (USM-1 manufactured by ASONE Corporation) for 5 minutes. D50 can be measured using (Nikkiso 9320-HRA X-100).
  • the content of the silver powder and / or silver coat powder of the component (A) is not particularly limited, but the component (A) with respect to the total content of the components (A) and (B) in the conductive film forming agent is 100% by mass.
  • the content of is preferably in the range of 80 to 98% by mass, more preferably 85 to 98% by mass, and still more preferably 90 to 98% by mass. Specific resistance can be made smaller by being 85 mass% or more, and sprayability can be improved by being 98 mass% or less.
  • the cellulose nanofiber (B) is a cellulose fiber having a nanometer-level fiber diameter.
  • the number average fiber diameter of the cellulose nanofiber is not particularly limited, and may be, for example, 3 to 800 nm, 3 to 400 nm, 3 to 100 nm, or 3 to 30 nm.
  • the number average fiber diameter of cellulose nanofibers can be measured as follows. That is, a cellulose nanofiber dispersion (for example, a methanol dispersion in Production Example 1 described later and an N-methylpyrrolidone dispersion in Production Example 2) having a solid content of 0.05 to 0.1% by mass was prepared. The dispersion is cast on a carbon film-coated grid that has been subjected to hydrophilization treatment to obtain a sample for observation with a transmission electron microscope (TEM). The observation sample may be negatively stained with, for example, a 2% by mass uranyl acetate aqueous solution.
  • TEM transmission electron microscope
  • observation with an electron microscope image is performed at a magnification of 5000 times, 10000 times, or 50000 times depending on the size of the constituent fibers.
  • an axis having an arbitrary vertical and horizontal image width is assumed in the obtained image, and the sample and observation conditions (magnification, etc.) are adjusted so that 20 or more fibers intersect the axis.
  • two random axes, vertical and horizontal, per image are drawn on this image, and the fiber diameter of the fiber that intersects the axis is visually read.
  • the cellulose nanofiber one having a cellulose I-type crystal structure is used.
  • anion-modified cellulose nanofiber in which an anionic group is introduced into a glucose unit in a cellulose molecule is preferably used.
  • the anionic group include at least one selected from the group consisting of a carboxyl group, a phosphoric acid group, a sulfonic acid group, and a sulfuric acid group.
  • the carboxyl group is a concept including not only an acid form (—COOH) but also a salt form, that is, a carboxylate group (—COOX, where X is a cation forming a salt with a carboxylic acid).
  • the phosphoric acid group, the sulfonic acid group and the sulfuric acid group are concepts including not only the acid type but also the salt type.
  • the anionic group is preferably a carboxyl group.
  • cellulose nanofibers containing carboxyl groups include oxidized cellulose nanofibers formed by oxidizing the hydroxyl groups of glucose units in cellulose molecules, and carboxymethylated celluloses formed by carboxymethylating the hydroxyl groups of glucose units in cellulose molecules. Nanofiber is mentioned.
  • oxidized cellulose nanofiber examples include those in which the hydroxyl group at the C6 position of the glucose unit in the cellulose molecule is selectively oxidized and modified to a carboxyl group.
  • Oxidized cellulose nanofibers can be obtained by oxidizing natural cellulose such as wood pulp using a co-oxidant in the presence of an N-oxyl compound, and then performing a defibration (miniaturization) treatment.
  • N-oxyl compound a compound having a nitroxy radical generally used as an oxidation catalyst is used, for example, a piperidine nitroxyoxy radical, particularly a 2,2,6,6-tetramethylpiperidinooxy radical (TEMPO).
  • TEMPO 2,2,6,6-tetramethylpiperidinooxy radical
  • Cellulose nanofibers oxidized with TEMPO are generally called TEMPO-oxidized cellulose nanofibers, and can be used in this embodiment.
  • the oxidized cellulose nanofiber may have an aldehyde group or a ketone group together with the carboxyl group.
  • the amount of the anionic group in the cellulose nanofiber is not particularly limited. It may be 05 to 3.0 mmol / g or 0.5 to 2.5 mmol / g.
  • the amount of anionic group for example, in the case of a carboxyl group, 60 mL of a 0.5 to 1% by mass slurry is prepared from a cellulose sample whose dry mass is precisely weighed, and the pH is adjusted to about 2.5 with a 0.1 M aqueous hydrochloric acid solution. Thereafter, 0.05M aqueous sodium hydroxide solution was added dropwise to measure the electrical conductivity, and continued until the pH reached about 11, and the hydroxylation consumed in the neutralization step of the weak acid where the change in electrical conductivity was gradual.
  • Cellulose nanofibers may be obtained by performing a defibrating process.
  • the defibrating treatment may be performed after the anionic group is introduced, or may be performed before the introduction.
  • the defibrating treatment can be performed using, for example, a homomixer under high-speed rotation, a high-pressure homogenizer, an ultrasonic dispersion processor, a beater, a disk type refiner, a conical type refiner, a double disk type refiner, or a grinder.
  • a cellulose nanofiber dispersion dispersed in a dispersion medium other than water examples include various organic solvents such as alcohol solvents such as methanol, ethanol and 2-propanol, and amides such as N-methylpyrrolidone, N, N-dimethylformamide and N, N-dimethylacetamide.
  • a system solvent is preferable from the viewpoint of dispersibility of cellulose nanofibers. Since these dispersion media are added to the conductive film forming agent together with the cellulose nanofibers by adding the cellulose nanofiber dispersion to the conductive film forming agent, Become.
  • cellulose nanofiber dispersion using an organic solvent as a dispersion medium
  • acid-type anion groups such as carboxyl groups are neutralized with polyetheramine in anion-modified cellulose nanofibers such as oxidized cellulose nanofibers. It is preferable that the dispersibility in the organic solvent can be improved.
  • the content of the cellulose nanofiber as the component (B) is not particularly limited, but the content of the component (B) with respect to the total content of the components (A) and (B) in the conductive film forming agent is 100% by mass.
  • the content is preferably in the range of 2 to 20% by mass, more preferably 2 to 15% by mass, and may be 2 to 10% by mass.
  • Component (C) The organic solvent as the component (C) functions as a dispersion medium for the components (A) and (B) in the conductive film forming agent.
  • the organic solvent is not particularly limited, but for example, methanol, ethanol, 2-propanol, isobutyl alcohol, 1-butanol, terpineol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, carbitol, ethylene glycol monobutyl ether, propylene glycol monomethyl Alcohol solvents such as ether, propylene glycol monoethyl ether, ethylene glycol, glycerin, etc .; Hydrocarbon solvents such as toluene, xylene, petroleum hydrocarbons; ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate , Ester solvents such as propylene glycol monomethyl ether acetate and carbitol acetate Ketone solvents such as acetone and methyl ethyl ketone; Ether solvents such as ethylene glycol dimethyl
  • the content of the organic solvent of component (C) is not particularly limited.
  • the total content of components (A) and (B) in the conductive film forming agent is 100 parts by mass, It may be 500 parts by mass or 50 to 400 parts by mass.
  • the conductive film forming agent according to this embodiment preferably does not substantially contain water as a dispersion medium. That is, in the conductive film forming agent according to the present embodiment, the dispersion medium is substantially composed of only an organic solvent, and thus the silver powder and / or silver-coated powder of the component (A) may be subjected to a hydrophobic treatment. , Its dispersibility can be improved.
  • the conductive film forming agent substantially does not contain water, even if the conductive film forming agent does not contain water or contains water, in the total amount of the dispersion medium of 100% by mass, It means that the amount of water is less than 10% by mass, more preferably less than 5% by mass, still more preferably less than 1% by mass.
  • the conductive film forming agent according to the present embodiment includes, in addition to the components (A) to (C) described above, for example, a binder resin, a curing agent, a colorant, a metal dispersant, You may mix
  • the method for producing the conductive film forming agent according to the present embodiment is not particularly limited, and a known method can be suitably used in the field of the conductive film forming agent.
  • a known method can be suitably used in the field of the conductive film forming agent.
  • prescribed mixture ratio, and mixes using a well-known mixer is mentioned.
  • the cellulose nanofiber of (B) component is added as a cellulose nanofiber dispersion which uses an organic solvent as a dispersion medium as mentioned above.
  • the viscosity of the conductive film forming agent according to the present embodiment is not particularly limited, and for example, the viscosity at 25 ° C. may be 50 Pa ⁇ s or less, or 20 Pa ⁇ s or less. From the viewpoint of sprayability, the smaller the viscosity, the better.
  • the viscosity of the conductive film forming agent can be obtained by measuring the viscosity ( ⁇ 1 rpm) at 1 rpm rotation (shear rate 2 s-1) at 25 ° C. using an E-type viscometer.
  • the conductive film forming agent according to the present embodiment is used for forming a conductive film. Specifically, it can be used for formation of a conductive film in an electromagnetic wave shield and formation of a conductive film (for example, wiring) in various electronic components.
  • a conductive film can be formed on a base material by applying a conductive film forming agent on the base material and curing it.
  • the coating method examples include a spray method and an ink jet method, and the spray method is preferable. That is, the conductive film forming agent according to a preferred embodiment is a conductive film forming agent for spraying used to form a conductive film by spraying.
  • the base material examples include a glass substrate, a ceramic substrate (such as an alumina substrate), and a flexible substrate (such as a PET film).
  • the coating film formed on the substrate can be cured by, for example, drying at 60 to 150 ° C. for 1 to 60 minutes and then low-temperature baking at 100 to 250 ° C. for 1 to 60 minutes to form a conductive film. be able to.
  • the specific resistance (volume resistivity) of the conductive film formed by the conductive film forming agent according to this embodiment is not particularly limited, but is preferably 1 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less, and preferably 1 ⁇ 10 ⁇ 6. It may be ⁇ 1 ⁇ 10 ⁇ 4 ⁇ ⁇ cm.
  • the dispersibility of the silver powder and / or the silver coated powder is good due to the use of the organic solvent as the dispersion medium.
  • the conductive film forming agent has high thixotropy, so that it is possible to achieve both coating film formability such as sprayability and storage stability, and has good conductivity. A conductive film can be formed.
  • the evaluation method of the conductive film forming agent is as follows.
  • TI value Only conductive film forming agents having a dispersibility of “ ⁇ ” were evaluated.
  • the viscosity of the conductive film forming agent was measured at 25 ° C. using an E type viscometer (TV-22 type viscometer cone plate type manufactured by Toki Sangyo Co., Ltd.). Viscosity ( ⁇ 1 rpm) at 1 rpm rotation (shear rate 2 s-1) and viscosity ( ⁇ 10 rpm) at 10 rpm rotation (shear rate 20 s-1) are measured, and the former is divided by the latter to give a TI value ( ⁇ 1 rpm / ⁇ 10 rpm) Was calculated.
  • the film thickness of the formed conductive film was measured with a surface roughness meter (Surfcom 480A manufactured by Tokyo Seimitsu Co., Ltd.), and the electrical resistance at room temperature (25 ° C.) was measured with an electrical resistance measuring device (low resistivity meter manufactured by Mitsubishi Chemical Analytical Co., Ltd.) (Loresta GP, four-terminal four-probe method), and the specific resistance (volume resistivity) was calculated and evaluated based on the film thickness, electrical resistance, and aspect ratio of the conductive film.
  • reaction time 120 minutes.
  • solid-liquid separation was performed with a centrifuge, and pure water was added to adjust the solid content concentration to 4% by mass.
  • the pH of the slurry was adjusted to 10 with a 24 mass% NaOH aqueous solution.
  • the slurry was reduced to 30 ° C. by adding 0.2 mmol / g of sodium borohydride to the cellulose fiber and reacting for 2 hours.
  • the obtained CNF dispersion 1 is a 2.5 mass% dispersion of TEMPO-oxidized cellulose nanofibers using methanol as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 2.1 mmol / g, the number average fiber.
  • the diameter was 4 nm and had an I-type crystal structure.
  • 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing with water, and pure water was added to adjust the solid content concentration to 4% by mass. Thereafter, the pH of the slurry was adjusted to 10 with a 24 mass% NaOH aqueous solution. The slurry was reduced to 30 ° C. by adding 0.2 mmol / g of sodium borohydride to the cellulose fiber and reacting for 2 hours. After the reaction, 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing to obtain modified cellulose fibers.
  • NMP N-methylpyrrolidone
  • the obtained CNF dispersion 2 is a 9.0 mass% dispersion of TEMPO-oxidized cellulose nanofibers using NMP as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 1.8 mmol / g, the number average fiber.
  • the diameter was 4 nm and had an I-type crystal structure.
  • 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing to obtain cellulose fibers having oxidized fiber surfaces.
  • pure water is added to this cellulose fiber to dilute it to 2% by mass, and it is treated once at a pressure of 100 MPa using a high-pressure homogenizer (manufactured by Sanwa Engineering Co., Ltd., H11), whereby a gel composition (CNF dispersion) is obtained. 3) was produced.
  • the obtained CNF dispersion 3 is a 2.0 mass% dispersion of TEMPO oxidized cellulose nanofibers using water as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 2.1 mmol / g, the number average fiber.
  • the diameter was 4 nm and had an I-type crystal structure.
  • Example 1 Preparation of conductive film forming agent
  • Flaky silver powder (trade name: SILCOAT AgC-A, manufactured by Fukuda Metal Foil Powder Co., Ltd., specific surface area 0.6 to 0.9 m 2 / g, 50% average particle size 4.65 ⁇ m) 0.95 parts by mass
  • 2.00 parts by mass of CNF dispersion 1 (2.5% by mass dispersion of TEMPO-oxidized cellulose nanofiber using methanol as a dispersion medium) obtained in Production Example 1 was measured in a glass container, and rotation and revolution Mixing was performed at 1500 rpm for 5 minutes using a mixer (manufactured by EME, V-mini300) to obtain a conductive film forming agent according to Example 1.
  • the mixing ratio of silver powder and cellulose nanofibers (each content in the solid content) is 95% by mass of silver powder and 5% by mass of cellulose nanofibers.
  • Example 2 Comparative Examples 1 to 7
  • a conductive film forming agent was prepared in the same manner as in Example 1 except that the types and blending amounts of the components were as shown in Table 1 below.
  • the mixing ratio of silver powder and cellulose nanofiber or binder resin in the solid content was 95% by mass of silver powder, and 5% by mass of cellulose nanofiber or binder resin. Met.
  • binder resins 1 and 2 in the table are as follows.
  • Binder resin 1 Epoxy resin, trade name: Adeka Resin EP-4901E, manufactured by ADEKA Corporation
  • Binder resin 2 ethyl cellulose, trade name: ethyl cellulose Viscosity: 80-120 cps (5% solution, 25 ° C.), manufactured by Nacalai Tesque
  • the conductive film forming agents obtained in Examples 1 and 2 and Comparative Examples 1 to 7 were evaluated for dispersibility, sprayability, storage stability, TI value, and specific resistance. The results are as shown in Table 1. In Comparative Examples 1, 3, and 7, it was impossible to evaluate other than dispersibility because a conductive film forming agent having good dispersibility could not be obtained.
  • the conductive film forming agent of Examples 1 and 2 containing cellulose nanofibers using an organic solvent as a dispersion medium has excellent dispersibility of silver powder and high thixotropy (TI). It had good storage stability and could be sprayed.
  • the conductive film obtained from the conductive film forming agent had low specific resistance and good conductivity.
  • Comparative Examples 1 and 3 in which the cellulose nanofibers in Examples 1 and 2 were replaced with binder resin 1 (epoxy resin) resulted in poor dispersion and silver powder settled. Since the viscosity of the conductive film forming agent of Comparative Examples 1 and 3 was considerably lower than that of Examples 1 and 2, when the amount of the organic solvent was reduced as in Comparative Examples 2 and 4 to increase the viscosity, dispersibility Although the storage stability was improved, the sprayability was not good.
  • binder resin 1 epoxy resin

Abstract

Provided is a conductive film forming agent that has excellent storage stability and film-forming properties such as for spraying and is capable of forming a conductive film which has good conductivity. A conductive film forming agent according an embodiment of the present invention comprises (A) silver powder and/or silver coated powder, (B) cellulose nanofibers, and (C) an organic solvent. A conductive film according an embodiment of the present invention is formed by applying the conductive film forming agent.

Description

導電膜形成剤Conductive film forming agent
　本発明は、導電膜形成剤、及び、それを用いて形成される導電膜に関する。 The present invention relates to a conductive film forming agent and a conductive film formed using the same.
　電磁波シールドや電子部品などにおいて導電膜を形成するための導電膜形成剤として、スプレー法やインクジェット法などの量産性に優れた塗布方法に利用可能でかつ保存安定性に優れたものが求められている。 As a conductive film forming agent for forming a conductive film in electromagnetic wave shields and electronic parts, there is a demand for a material that can be used in a coating method with excellent mass productivity such as a spray method or an ink jet method and has excellent storage stability. Yes.
　従来、例えば特許文献１には、インクジェット法に好適な導電膜形成剤として、炭素数８以下のアルカンと、イソパラフィン及び／又は流動パラフィンと、金属及び有機物からなる粒子径１００ｎｍ以下の金属ナノ粒子とを含む金属ナノ粒子分散液が開示されている。特許文献１では、特定のアルカンを含有させることで良好な塗布性を得ているが、使用する金属ナノ粒子は粒子径が１００ｎｍ以下と小さいため、表面エネルギーが非常に大きくなり、凝集が生じやすく、金属ナノ粒子分散液の保存安定性の低下が懸念される。 Conventionally, for example, in Patent Document 1, as a conductive film forming agent suitable for the ink jet method, alkanes having 8 or less carbon atoms, isoparaffins and / or liquid paraffin, and metal nanoparticles having a particle diameter of 100 nm or less made of metal and organic matter, Metal nanoparticle dispersions containing are disclosed. In Patent Document 1, good coating properties are obtained by containing a specific alkane. However, since the metal nanoparticles used have a small particle diameter of 100 nm or less, the surface energy becomes very large and aggregation tends to occur. There is a concern that the storage stability of the metal nanoparticle dispersion is lowered.
　特許文献２には、スプレー法に好適でかつ良好な保存安定性を有する無機粒子膜形成剤が開示されている。特許文献２では、セルロース繊維の水分散体および分散媒としての水を含有することで、スプレー性と保存安定性に優れた無機粒子膜形成剤が得られることが開示されている。 Patent Document 2 discloses an inorganic particle film forming agent that is suitable for the spray method and has good storage stability. Patent Document 2 discloses that an inorganic particle film forming agent excellent in sprayability and storage stability can be obtained by containing an aqueous dispersion of cellulose fibers and water as a dispersion medium.
　優れた導電性を有する導電膜の形成には、金属粉末（即ち、導電性粉末）として銀粉を用いることが好ましいが、銀粉は一般に製造時に疎水化処理として脂肪酸で表面処理されていることが多く、水との親和性が低いため、特許文献２に記載のように分散媒として水を用いる技術に適用することは難しい。 For the formation of a conductive film having excellent conductivity, it is preferable to use silver powder as a metal powder (that is, conductive powder), but silver powder is generally surface-treated with a fatty acid as a hydrophobic treatment at the time of production. Since the affinity with water is low, it is difficult to apply to a technique using water as a dispersion medium as described in Patent Document 2.
特開２０１０－１９６１５０号公報JP 2010-196150 A 特開２０１６－１７１６１号公報JP 2016-17161 A
　本発明の実施形態は、スプレー性等の塗膜形成性と保存安定性に優れるとともに、良好な導電性を有する導電膜を形成することができる導電膜形成剤を提供することを目的とする。 Embodiment of this invention aims at providing the electrically conductive film formation agent which can form the electrically conductive film which is excellent in coating-film formation property, such as sprayability, and storage stability, and favorable electroconductivity.
　本発明の実施形態に係る導電膜形成剤は、下記の（Ａ）～（Ｃ）成分を含有するものである。
（Ａ）銀粉及び／又は銀コート粉
（Ｂ）セルロースナノファイバー
（Ｃ）有機溶媒
　本実施形態に係る導電膜は、該導電膜形成剤を塗布してなるものである。 The conductive film forming agent according to the embodiment of the present invention contains the following components (A) to (C).
(A) Silver powder and / or silver coat powder (B) Cellulose nanofiber (C) Organic solvent The electrically conductive film which concerns on this embodiment apply | coats this electrically conductive film formation agent.
　本発明の実施形態に係る導電膜形成剤であると、スプレー性等の塗膜形成性と保存安定性に優れるとともに、良好な導電性を有する導電膜を形成することができる。 When the conductive film forming agent according to the embodiment of the present invention is used, it is possible to form a conductive film having excellent conductivity while being excellent in coating film forming properties such as sprayability and storage stability.
　以下、本発明の好ましい実施形態について詳細に説明する。 Hereinafter, preferred embodiments of the present invention will be described in detail.
　本実施形態に係る導電膜形成剤は、（Ａ）銀粉及び／又は銀コート粉と、（Ｂ）セルロースナノファイバーと、（Ｃ）有機溶媒と、を含有するものであり、有機溶媒を分散媒として銀粉及び／又は銀コート粉とセルロースナノファイバーが分散した分散液である。本実施形態によれば、分散媒として有機溶媒を用いることにより、金属粉末として銀粉及び／又は銀コート粉を用いることができ、そのため、良好な導電性を付与することができる。また、セルロースナノファイバーを含有することにより、導電膜形成剤にチクソ性（チクソトロピー）を付与することができ、スプレーなどの塗布時に流動性を高めて塗膜形成性を向上しつつ、保存安定性を高めることができる。 The conductive film forming agent according to the present embodiment contains (A) silver powder and / or silver-coated powder, (B) cellulose nanofiber, and (C) an organic solvent, and the organic solvent is used as a dispersion medium. As a dispersion liquid in which silver powder and / or silver-coated powder and cellulose nanofiber are dispersed. According to this embodiment, by using an organic solvent as a dispersion medium, silver powder and / or silver-coated powder can be used as the metal powder, and therefore, good conductivity can be imparted. In addition, by containing cellulose nanofibers, it is possible to impart thixotropy (thixotropy) to the conductive film forming agent, improve fluidity at the time of application such as spraying, improve coating film formation, and storage stability. Can be increased.
　［（Ａ）成分］
　（Ａ）成分として、銀粉（即ち、銀の粉末）と銀コート粉のいずれか一方又は双方を用いる。銀粉及び／又は銀コート粉の具体的な構成は特に限定されず、一般に導電膜形成剤に使用されている各種銀粉や銀コート粉を用いることができる。その形状としては、特に限定されず、例えば球状、フレーク状など種々の形状が挙げられるが、比抵抗が低くなることからフレーク状のものが好ましい。 [(A) component]
As the component (A), one or both of silver powder (that is, silver powder) and silver coat powder is used. The specific structure of silver powder and / or silver coat powder is not specifically limited, The various silver powder and silver coat powder which are generally used for the electrically conductive film formation agent can be used. The shape is not particularly limited, and examples thereof include various shapes such as a spherical shape and a flake shape, but a flake shape is preferable because the specific resistance is lowered.
　銀コート粉とは、表面が銀で被覆された粉末であり、例えば、銀コート銅粉、銀コートニッケル粉、銀コートアルミ粉などの銀コート金属粉、銀コートガラス粉、銀コート樹脂粉などが挙げられる。 Silver coated powder is powder coated with silver on the surface, for example, silver coated metal powder such as silver coated copper powder, silver coated nickel powder, silver coated aluminum powder, silver coated glass powder, silver coated resin powder, etc. Is mentioned.
　銀粉及び／又は銀コート粉としては、疎水化処理、例えば脂肪酸で表面処理されたものを用いてもよい。 As silver powder and / or silver coat powder, a hydrophobic treatment, for example, a surface treated with a fatty acid may be used.
　（Ａ）成分の銀粉及び／又は銀コート粉の粒径は、特に限定されないが、優れた導電性を付与する観点から、５０％平均粒子径（Ｄ５０）が１００ｎｍ以上、即ち０．１μｍ以上であるものが好ましい。Ｄ５０は、０．１～２０μｍでもよく、１～１０μｍでもよく、２～５μｍでもよい。 The particle diameter of the silver powder and / or silver coat powder of the component (A) is not particularly limited, but from the viewpoint of imparting excellent conductivity, the 50% average particle diameter (D50) is 100 nm or more, that is, 0.1 μm or more. Some are preferred. D50 may be 0.1 to 20 μm, 1 to 10 μm, or 2 to 5 μm.
　ここで、Ｄ５０は、レーザー回折法により測定することができる。例えば、金属粉末０．３ｇを５０ｍｌビーカーに秤量し、イソプロピルアルコール３０ｍｌを加えた後、超音波洗浄器（アズワン株式会社製ＵＳＭ－１）により５分間処理して分散させ、マイクロトラック粒度分布測定装置（日機装株式会社製９３２０－ＨＲＡ　Ｘ－１００）を用いてＤ５０を測定することができる。 Here, D50 can be measured by a laser diffraction method. For example, 0.3 g of metal powder is weighed into a 50 ml beaker, 30 ml of isopropyl alcohol is added, and then dispersed by treatment with an ultrasonic cleaner (USM-1 manufactured by ASONE Corporation) for 5 minutes. D50 can be measured using (Nikkiso 9320-HRA X-100).
　（Ａ）成分の銀粉及び／又は銀コート粉の含有量は、特に限定されないが、導電膜形成剤中の（Ａ）成分と（Ｂ）成分の含有量の合計１００質量％に対する（Ａ）成分の含有量が８０～９８質量％の範囲内であることが好ましく、より好ましくは８５～９８重量％であり、更に好ましくは９０～９８質量％である。８５質量％以上であることにより比抵抗をより小さくすることができ、また、９８質量％以下であることによりスプレー性を向上することができる。 The content of the silver powder and / or silver coat powder of the component (A) is not particularly limited, but the component (A) with respect to the total content of the components (A) and (B) in the conductive film forming agent is 100% by mass. The content of is preferably in the range of 80 to 98% by mass, more preferably 85 to 98% by mass, and still more preferably 90 to 98% by mass. Specific resistance can be made smaller by being 85 mass% or more, and sprayability can be improved by being 98 mass% or less.
　［（Ｂ）成分］
　（Ｂ）成分のセルロースナノファイバーは、ナノメートルレベルの繊維径を持つセルロース繊維である。セルロースナノファイバーの数平均繊維径は、特に限定されず、例えば、３～８００ｎｍでもよく、３～４００ｎｍでもよく、３～１００ｎｍでもよく、３～３０ｎｍでもよい。 [Component (B)]
The cellulose nanofiber (B) is a cellulose fiber having a nanometer-level fiber diameter. The number average fiber diameter of the cellulose nanofiber is not particularly limited, and may be, for example, 3 to 800 nm, 3 to 400 nm, 3 to 100 nm, or 3 to 30 nm.
　セルロースナノファイバーの数平均繊維径は、次のようにして測定することができる。即ち、固形分率で０．０５～０．１質量％のセルロースナノファイバー分散体（例えば、後述する製造例１ではメタノール分散体、製造例２ではＮ－メチルピロリドン分散体）を調製し、その分散体を、親水化処理済みのカーボン膜被覆グリッド上にキャストして、透過型電子顕微鏡（ＴＥＭ）の観察用試料とする。観察用試料は、例えば２質量％ウラニルアセテート水溶液でネガティブ染色してもよい。そして、構成する繊維の大きさに応じて５０００倍、１００００倍あるいは５００００倍のいずれかの倍率で電子顕微鏡画像による観察を行う。その際に、得られた画像内に縦横任意の画像幅の軸を想定し、その軸に対し、２０本以上の繊維が交差するよう、試料および観察条件（倍率等）を調節する。そして、この条件を満たす観察画像を得た後、この画像に対し、１枚の画像当たり縦横２本ずつの無作為な軸を引き、軸に交錯する繊維の繊維径を目視で読み取っていく。このようにして、最低３枚の重複しない表面部分の画像を、電子顕微鏡で撮影し、各々２つの軸に交錯する繊維の繊維径の値を読み取る（したがって、最低２０本×２×３＝１２０本の繊維径の情報が得られる）。このようにして得られた繊維径の相加平均を数平均繊維径とする。 The number average fiber diameter of cellulose nanofibers can be measured as follows. That is, a cellulose nanofiber dispersion (for example, a methanol dispersion in Production Example 1 described later and an N-methylpyrrolidone dispersion in Production Example 2) having a solid content of 0.05 to 0.1% by mass was prepared. The dispersion is cast on a carbon film-coated grid that has been subjected to hydrophilization treatment to obtain a sample for observation with a transmission electron microscope (TEM). The observation sample may be negatively stained with, for example, a 2% by mass uranyl acetate aqueous solution. Then, observation with an electron microscope image is performed at a magnification of 5000 times, 10000 times, or 50000 times depending on the size of the constituent fibers. At that time, an axis having an arbitrary vertical and horizontal image width is assumed in the obtained image, and the sample and observation conditions (magnification, etc.) are adjusted so that 20 or more fibers intersect the axis. Then, after obtaining an observation image that satisfies this condition, two random axes, vertical and horizontal, per image are drawn on this image, and the fiber diameter of the fiber that intersects the axis is visually read. In this way, images of at least three non-overlapping surface portions are taken with an electron microscope, and the fiber diameter values of the fibers intersecting with each of the two axes are read (thus, at least 20 × 2 × 3 = 120). Information on the fiber diameter of the book is obtained). The arithmetic average of the fiber diameters thus obtained is taken as the number average fiber diameter.
　セルロースナノファイバーとしては、セルロースＩ型結晶構造を有するものが用いられる。セルロースナノファイバーを構成するセルロースがＩ型結晶構造を有することは、例えば、広角Ｘ線回折像測定により得られる回折プロファイルにおいて、２θ＝１４°～１７°付近と、２θ＝２２°～２３°付近の２つの位置に典型的なピークをもつことから同定することができる。 As the cellulose nanofiber, one having a cellulose I-type crystal structure is used. The cellulose constituting the cellulose nanofiber has a type I crystal structure, for example, in the diffraction profile obtained by wide-angle X-ray diffraction image measurement, in the vicinity of 2θ = 14 ° to 17 ° and 2θ = 22 ° to 23 °. Can be identified by having typical peaks at these two positions.
　セルロースナノファイバーとしては、セルロース分子中のグルコースユニットにアニオン基が導入されたアニオン変性セルロースナノファイバーが好ましく用いられる。アニオン基としては、例えば、カルボキシル基、リン酸基、スルホン酸基、及び硫酸基からなる群から選択される少なくとも１種が挙げられる。本明細書において、カルボキシル基は、酸型（－ＣＯＯＨ）だけでなく、塩型、即ちカルボン酸塩基（－ＣＯＯＸ、ここでＸはカルボン酸と塩を形成する陽イオン）も含む概念である。リン酸基、スルホン酸基及び硫酸基についても、同様に、酸型だけでなく、塩型も含む概念である。 As the cellulose nanofiber, anion-modified cellulose nanofiber in which an anionic group is introduced into a glucose unit in a cellulose molecule is preferably used. Examples of the anionic group include at least one selected from the group consisting of a carboxyl group, a phosphoric acid group, a sulfonic acid group, and a sulfuric acid group. In the present specification, the carboxyl group is a concept including not only an acid form (—COOH) but also a salt form, that is, a carboxylate group (—COOX, where X is a cation forming a salt with a carboxylic acid). Similarly, the phosphoric acid group, the sulfonic acid group and the sulfuric acid group are concepts including not only the acid type but also the salt type.
　一実施形態において、アニオン基としてはカルボキシル基が好ましい。カルボキシル基を含有するセルロースナノファイバーとしては、例えば、セルロース分子中のグルコースユニットの水酸基を酸化してなる酸化セルロースナノファイバーや、セルロース分子中のグルコースユニットの水酸基をカルボキシメチル化してなるカルボキシメチル化セルロースナノファイバーが挙げられる。 In one embodiment, the anionic group is preferably a carboxyl group. Examples of cellulose nanofibers containing carboxyl groups include oxidized cellulose nanofibers formed by oxidizing the hydroxyl groups of glucose units in cellulose molecules, and carboxymethylated celluloses formed by carboxymethylating the hydroxyl groups of glucose units in cellulose molecules. Nanofiber is mentioned.
　好ましい実施形態に係る酸化セルロースナノファイバーとしては、セルロース分子中のグルコースユニットのＣ６位の水酸基が選択的に酸化されてカルボキシル基に変性されたものが挙げられる。酸化セルロースナノファイバーは、木材パルプなどの天然セルロースをＮ－オキシル化合物の存在下、共酸化剤を用いて酸化させ、解繊（微細化）処理することにより得られる。Ｎ－オキシル化合物としては、一般に酸化触媒として用いられるニトロキシラジカルを有する化合物が用いられ、例えばピペリジンニトロキシオキシラジカルであり、特に２，２，６，６－テトラメチルピペリジノオキシラジカル（ＴＥＭＰＯ）または４－アセトアミド－ＴＥＭＰＯが好ましい。ＴＥＭＰＯで酸化されたセルロースナノファイバーは、一般にＴＥＭＰＯ酸化セルロースナノファイバーと称されており、本実施形態でも使用することができる。なお、酸化セルロースナノファイバーは、カルボキシル基とともに、アルデヒド基又はケトン基を有していてもよい。 Examples of the oxidized cellulose nanofiber according to a preferred embodiment include those in which the hydroxyl group at the C6 position of the glucose unit in the cellulose molecule is selectively oxidized and modified to a carboxyl group. Oxidized cellulose nanofibers can be obtained by oxidizing natural cellulose such as wood pulp using a co-oxidant in the presence of an N-oxyl compound, and then performing a defibration (miniaturization) treatment. As the N-oxyl compound, a compound having a nitroxy radical generally used as an oxidation catalyst is used, for example, a piperidine nitroxyoxy radical, particularly a 2,2,6,6-tetramethylpiperidinooxy radical (TEMPO). ) Or 4-acetamido-TEMPO is preferred. Cellulose nanofibers oxidized with TEMPO are generally called TEMPO-oxidized cellulose nanofibers, and can be used in this embodiment. The oxidized cellulose nanofiber may have an aldehyde group or a ketone group together with the carboxyl group.
　セルロースナノファイバーにおけるアニオン基の量は、特に限定されず、例えば、０．
０５～３．０ｍｍｏｌ／ｇでもよく、０．５～２．５ｍｍｏｌ／ｇでもよい。アニオン基の量は、例えば、カルボキシル基の場合、乾燥質量を精秤したセルロース試料から０．５～１質量％スラリーを６０ｍＬ調製し、０．１Ｍの塩酸水溶液によってｐＨを約２．５とした後、０．０５Ｍの水酸化ナトリウム水溶液を滴下して、電気伝導度測定を行い、ｐＨが約１１になるまで続け、電気伝導度の変化が緩やかな弱酸の中和段階において消費された水酸化ナトリウム量（Ｖ）から、下記式に従い求めることができる。リン酸基についても、同様の電気伝導度測定により測定することができる。その他のアニオン基についても公知の方法で測定すればよい。
アニオン基量(mmol/g)＝Ｖ(mL)×〔0.05／セルロース試料質量(g)〕 The amount of the anionic group in the cellulose nanofiber is not particularly limited.
It may be 05 to 3.0 mmol / g or 0.5 to 2.5 mmol / g. As for the amount of anionic group, for example, in the case of a carboxyl group, 60 mL of a 0.5 to 1% by mass slurry is prepared from a cellulose sample whose dry mass is precisely weighed, and the pH is adjusted to about 2.5 with a 0.1 M aqueous hydrochloric acid solution. Thereafter, 0.05M aqueous sodium hydroxide solution was added dropwise to measure the electrical conductivity, and continued until the pH reached about 11, and the hydroxylation consumed in the neutralization step of the weak acid where the change in electrical conductivity was gradual. It can obtain | require from a sodium amount (V) according to a following formula. The phosphate group can also be measured by the same electric conductivity measurement. Other anionic groups may be measured by a known method.
Anion group amount (mmol / g) = V (mL) × [0.05 / cellulose sample mass (g)]
　セルロースナノファイバーは、解繊処理を行うことにより得てもよい。解繊処理は、アニオン基を導入してから実施してもよく、導入前に実施してもよい。解繊処理としては、例えば、高速回転下でのホモミキサー、高圧ホモジナイザー、超音波分散処理機、ビーター、ディスク型レファイナー、コニカル型レファイナー、ダブルディスク型レファイナー、グラインダー等を用いて行うことができる。 Cellulose nanofibers may be obtained by performing a defibrating process. The defibrating treatment may be performed after the anionic group is introduced, or may be performed before the introduction. The defibrating treatment can be performed using, for example, a homomixer under high-speed rotation, a high-pressure homogenizer, an ultrasonic dispersion processor, a beater, a disk type refiner, a conical type refiner, a double disk type refiner, or a grinder.
　導電膜形成剤にセルロースナノファイバーを配合するに際しては、水以外の分散媒に分散されたセルロースナノファイバー分散体を用いることが好ましい。水以外の分散媒としては各種有機溶媒が挙げられ、例えば、メタノール、エタノール、２－プロパノールなどのアルコール系溶媒、Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミドなどのアミド系溶媒が、セルロースナノファイバーの分散性の観点から好ましい。これらの分散媒は、セルロースナノファイバー分散体を導電膜形成剤に添加することにより、セルロースナノファイバーとともに導電膜形成剤に配合されるため、（Ｃ）成分である有機溶媒の一部又は全部となる。 When blending cellulose nanofibers in the conductive film forming agent, it is preferable to use a cellulose nanofiber dispersion dispersed in a dispersion medium other than water. Examples of the dispersion medium other than water include various organic solvents such as alcohol solvents such as methanol, ethanol and 2-propanol, and amides such as N-methylpyrrolidone, N, N-dimethylformamide and N, N-dimethylacetamide. A system solvent is preferable from the viewpoint of dispersibility of cellulose nanofibers. Since these dispersion media are added to the conductive film forming agent together with the cellulose nanofibers by adding the cellulose nanofiber dispersion to the conductive film forming agent, Become.
　有機溶媒を分散媒とするセルロースナノファイバー分散体を得るためには、酸化セルロースナノファイバーなどのアニオン変性セルロースナノファイバーにおいて、カルボキシル基などの酸型のアニオン基がポリエーテルアミンで中和されていることが好ましく、有機溶媒に対する分散性を向上することができる。 In order to obtain a cellulose nanofiber dispersion using an organic solvent as a dispersion medium, acid-type anion groups such as carboxyl groups are neutralized with polyetheramine in anion-modified cellulose nanofibers such as oxidized cellulose nanofibers. It is preferable that the dispersibility in the organic solvent can be improved.
　（Ｂ）成分のセルロースナノファイバーの含有量は、特に限定されないが、導電膜形成剤中の（Ａ）成分と（Ｂ）成分の含有量の合計１００質量％に対する（Ｂ）成分の含有量が２～２０質量％の範囲内であることが好ましく、より好ましくは２～１５重量％であり、２～１０質量％でもよい。 The content of the cellulose nanofiber as the component (B) is not particularly limited, but the content of the component (B) with respect to the total content of the components (A) and (B) in the conductive film forming agent is 100% by mass. The content is preferably in the range of 2 to 20% by mass, more preferably 2 to 15% by mass, and may be 2 to 10% by mass.
　［（Ｃ）成分］
　（Ｃ）成分の有機溶媒は、導電膜形成剤において、（Ａ）成分と（Ｂ）成分に対する分散媒として機能するものである。 [Component (C)]
The organic solvent as the component (C) functions as a dispersion medium for the components (A) and (B) in the conductive film forming agent.
　有機溶媒としては、特に限定されないが、例えば、メタノール、エタノール、２－プロパノール、イソブチルアルコール、１－ブタノール、テルピネオール、ジアセトンアルコール、メチルセロソルブ、エチルセロソルブ、カルビトール、エチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、エチレングリコール、グリセリン等などのアルコール系溶媒；　トルエン、キシレン、石油系炭化水素などの炭化水素系溶媒；　酢酸エチル、酢酸ブチル、ジエチレングリコールモノエチルエーテルアセテート、ジエチレングリコールモノブチルエーテルアセテート、プロピレングリコールモノメチルエーテルアセテート、カルビトールアセテートなどのエステル系溶媒；　アセトン、メチルエチルケトンなどのケトン系溶媒；　エチレングリコールジメチルエーテル、１，４－ジオキサン、テトラヒドロフランなどのエーテル系溶媒；　Ｎ－メチルピロリドン、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ，Ｎ－ジメチルアセトアミドなどのアミド系溶媒などが挙げられ、これらはいずれか１種又は２種以上組み合わせて用いることができる。これらの中でも、アルコール系溶媒及び／又はアミド系溶媒が好ましい。 The organic solvent is not particularly limited, but for example, methanol, ethanol, 2-propanol, isobutyl alcohol, 1-butanol, terpineol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, carbitol, ethylene glycol monobutyl ether, propylene glycol monomethyl Alcohol solvents such as ether, propylene glycol monoethyl ether, ethylene glycol, glycerin, etc .; Hydrocarbon solvents such as toluene, xylene, petroleum hydrocarbons; ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate , Ester solvents such as propylene glycol monomethyl ether acetate and carbitol acetate Ketone solvents such as acetone and methyl ethyl ketone; Ether solvents such as ethylene glycol dimethyl ether, 1,4-dioxane and tetrahydrofuran; Amide solvents such as N-methylpyrrolidone, N, N-dimethylformamide and N, N-dimethylacetamide Any of these may be used alone or in combination of two or more. Among these, alcohol solvents and / or amide solvents are preferable.
　（Ｃ）成分の有機溶媒の含有量は、特に限定されず、例えば、導電膜形成剤中の（Ａ）成分と（Ｂ）成分の含有量の合計を１００質量部としたときに、３０～５００質量部でもよく、５０～４００質量部でもよい。 The content of the organic solvent of component (C) is not particularly limited. For example, when the total content of components (A) and (B) in the conductive film forming agent is 100 parts by mass, It may be 500 parts by mass or 50 to 400 parts by mass.
　本実施形態に係る導電膜形成剤は、分散媒としての水を実質的に含まないことが好ましい。すなわち、本実施形態に係る導電膜形成剤において、分散媒は実質的に有機溶媒のみからなり、これにより（Ａ）成分の銀粉及び／又は銀コート粉が疎水化処理されたものであっても、その分散性を向上することができる。本明細書において、導電膜形成剤が水を実質的に含まないとは、導電膜形成剤が水を含まないか、または、水を含んでいたとしても、分散媒の総量１００質量％中、水の量が１０質量％未満であることを意味し、より好ましくは５質量％未満、更に好ましくは１質量％未満であることを意味する。 The conductive film forming agent according to this embodiment preferably does not substantially contain water as a dispersion medium. That is, in the conductive film forming agent according to the present embodiment, the dispersion medium is substantially composed of only an organic solvent, and thus the silver powder and / or silver-coated powder of the component (A) may be subjected to a hydrophobic treatment. , Its dispersibility can be improved. In this specification, the conductive film forming agent substantially does not contain water, even if the conductive film forming agent does not contain water or contains water, in the total amount of the dispersion medium of 100% by mass, It means that the amount of water is less than 10% by mass, more preferably less than 5% by mass, still more preferably less than 1% by mass.
　［導電膜形成剤］
　本実施形態に係る導電膜形成剤には、上記成分（Ａ）～（Ｃ）の他、本実施形態の効果を損なわない範囲で、例えば、バインダ樹脂、硬化剤、着色剤、金属分散剤、消泡剤、レベリング剤、酸化防止剤、紫外線吸収剤、カップリング剤、充填剤、粘度調整剤などの各種添加剤を配合してもよい。 [Conductive film forming agent]
The conductive film forming agent according to the present embodiment includes, in addition to the components (A) to (C) described above, for example, a binder resin, a curing agent, a colorant, a metal dispersant, You may mix | blend various additives, such as an antifoamer, a leveling agent, antioxidant, a ultraviolet absorber, a coupling agent, a filler, and a viscosity modifier.
　本実施形態に係る導電膜形成剤の製造方法は特に限定されず、導電膜形成剤の分野で公知の方法を好適に用いることができる。例えば、上述した各成分を所定の配合割合で配合し、公知の混合機を用いて混合する方法が挙げられる。その際、（Ｂ）成分のセルロースナノファイバーは、上記のように、有機溶媒を分散媒とするセルロースナノファイバー分散体として添加されることが好ましい。 The method for producing the conductive film forming agent according to the present embodiment is not particularly limited, and a known method can be suitably used in the field of the conductive film forming agent. For example, the method which mix | blends each component mentioned above by the predetermined | prescribed mixture ratio, and mixes using a well-known mixer is mentioned. In that case, it is preferable that the cellulose nanofiber of (B) component is added as a cellulose nanofiber dispersion which uses an organic solvent as a dispersion medium as mentioned above.
　本実施形態に係る導電膜形成剤の粘度は、特に限定されず、例えば２５℃における粘度が５０Ｐａ・ｓ以下でもよく、２０Ｐａ・ｓ以下でもよい。スプレー性の観点からは粘度が小さいほど好ましい。ここで、導電膜形成剤の粘度は、Ｅ型粘度計を用いて、２５℃において１ｒｐｍ回転時（ずり速度２ｓ－１）の粘度（η１ｒｐｍ）を測定することにより得られる。 The viscosity of the conductive film forming agent according to the present embodiment is not particularly limited, and for example, the viscosity at 25 ° C. may be 50 Pa · s or less, or 20 Pa · s or less. From the viewpoint of sprayability, the smaller the viscosity, the better. Here, the viscosity of the conductive film forming agent can be obtained by measuring the viscosity (η1 rpm) at 1 rpm rotation (shear rate 2 s-1) at 25 ° C. using an E-type viscometer.
　［導電膜形成剤の使用］
　本実施形態に係る導電膜形成剤は、導電膜を形成するために用いられる。詳細には、電磁波シールドにおける導電膜の形成や、各種電子部品における導電膜（例えば配線）の形成に用いることができる。 [Use of conductive film forming agent]
The conductive film forming agent according to the present embodiment is used for forming a conductive film. Specifically, it can be used for formation of a conductive film in an electromagnetic wave shield and formation of a conductive film (for example, wiring) in various electronic components.
　一実施形態において、基材上に導電膜形成剤を塗布し、これを硬化させることにより、基材上に導電膜を形成することができる。 In one embodiment, a conductive film can be formed on a base material by applying a conductive film forming agent on the base material and curing it.
　塗布方法としては、例えば、スプレー法やインクジェット法などが挙げられ、好ましくはスプレー法である。すなわち、好ましい一実施形態に係る導電膜形成剤は、スプレーにより導電膜を形成するよう用いられるスプレー用の導電膜形成剤である。 Examples of the coating method include a spray method and an ink jet method, and the spray method is preferable. That is, the conductive film forming agent according to a preferred embodiment is a conductive film forming agent for spraying used to form a conductive film by spraying.
　基材としては、例えば、ガラス基板、セラミック基板（アルミナ基板など）、フレキシブル基板（ＰＥＴフィルムなど）などが挙げられる。 Examples of the base material include a glass substrate, a ceramic substrate (such as an alumina substrate), and a flexible substrate (such as a PET film).
　基材上に形成された塗膜は、例えば６０～１５０℃で１～６０分間乾燥した後、１００～２５０℃で１～６０分間低温焼成することにより硬化させることができ、導電膜を形成することができる。 The coating film formed on the substrate can be cured by, for example, drying at 60 to 150 ° C. for 1 to 60 minutes and then low-temperature baking at 100 to 250 ° C. for 1 to 60 minutes to form a conductive film. be able to.
　本実施形態に係る導電膜形成剤により形成される導電膜の比抵抗（体積抵抗率）は、特に限定されないが、１×１０－３Ω・ｃｍ以下であることが好ましく、１×１０－６～１×１０－４Ω・ｃｍでもよい。 The specific resistance (volume resistivity) of the conductive film formed by the conductive film forming agent according to this embodiment is not particularly limited, but is preferably 1 × 10 −3 Ω · cm or less, and preferably 1 × 10 −6. It may be ˜1 × 10 −4 Ω · cm.
　［効果］
　本実施形態に係る導電膜形成剤であると、分散媒として有機溶媒を用いたことにより、銀粉及び／又は銀コート粉の分散性が良好である。また、セルロースナノファイバーを含有することにより、導電膜形成剤は高いチクソ性を有し、そのため、スプレー性等の塗膜形成性と保存安定性を両立することができ、良好な導電性を有する導電膜を形成することができる。 [effect]
When the conductive film forming agent according to this embodiment is used, the dispersibility of the silver powder and / or the silver coated powder is good due to the use of the organic solvent as the dispersion medium. In addition, by containing cellulose nanofibers, the conductive film forming agent has high thixotropy, so that it is possible to achieve both coating film formability such as sprayability and storage stability, and has good conductivity. A conductive film can be formed.
　以下、実施例により更に詳細に説明するが、本発明はこれらに限定されない。 Hereinafter, although an Example demonstrates in detail, this invention is not limited to these.
　導電膜形成剤の評価方法は以下の通りである。 The evaluation method of the conductive film forming agent is as follows.
　［分散性］
　調製直後の導電膜形成剤を静置して状態を目視で確認し、金属粉末の沈降が見られないときを「○」として、金属粉末の沈降が見られるときを「×」として評価した。 [Dispersibility]
The conductive film forming agent immediately after the preparation was allowed to stand and the state was visually confirmed. The case where no metal powder sedimentation was observed was evaluated as “◯”, and the case where the metal powder sedimentation was observed was evaluated as “x”.
　［スプレー性］
　分散性が「○」であった導電膜形成剤のみ評価対象とした。スプレー（三谷バルブ社製ノズルタイプＺ－７５－１－１）に導電膜形成剤を入れて、ノズルを一定の圧力で押して吹き付けを行った。そして、水をポジティブコントロール、１質量％キサンタンガム水溶液をネガティブコントロールとして、スプレー性の比較を行った。すなわち、水に近い使用感でスプレー状に吹き付けることができたものを「○」、１質量％キサンタンガム水溶液に近い使用感で、一部しかスプレー状に吹き付けることができなかったもの（直射状の吹き付けとなったもの）、及びスプレーできなかったものを「×」として評価した。 [Sprayability]
Only conductive film forming agents having a dispersibility of “◯” were evaluated. The conductive film forming agent was put into a spray (nozzle type Z-75-1-1 manufactured by Mitani Valve Co., Ltd.) and sprayed by pressing the nozzle at a constant pressure. Then, spray properties were compared using water as a positive control and a 1% by weight xanthan gum aqueous solution as a negative control. In other words, “○” indicates that the spray can be sprayed with a feeling close to that of water. What was sprayed) and those that could not be sprayed were evaluated as “x”.
　［保存安定性］
　分散性が「○」であった導電膜形成剤のみ評価対象とした。導電膜形成剤を２５℃で１晩静置した。導電膜形成剤の状態変化を目視で確認し、金属粉末の沈降が見られないときを「○」として、金属粉末の沈降が見られるときを「×」として評価した。 [Storage stability]
Only conductive film forming agents having a dispersibility of “◯” were evaluated. The conductive film forming agent was allowed to stand at 25 ° C. overnight. The state change of the conductive film forming agent was visually confirmed, and the case where no metal powder sedimentation was observed was evaluated as “◯”, and the time when the metal powder sedimentation was observed was evaluated as “X”.
　［ＴＩ値］
　分散性が「○」であった導電膜形成剤のみ評価対象とした。導電膜形成剤の粘度を２５℃でＥ型粘度計（東機産業社製ＴＶ－２２型粘度計コーンプレートタイプ）を用いて測定した。１ｒｐｍ回転時（ずり速度２ｓ－１）の粘度（η１ｒｐｍ）と、１０ｒｐｍ回転時（ずり速度２０ｓ－１）の粘度（η１０ｒｐｍ）を測定し、前者を後者で除してＴＩ値（η１ｒｐｍ／η１０ｒｐｍ）を算出した。 [TI value]
Only conductive film forming agents having a dispersibility of “◯” were evaluated. The viscosity of the conductive film forming agent was measured at 25 ° C. using an E type viscometer (TV-22 type viscometer cone plate type manufactured by Toki Sangyo Co., Ltd.). Viscosity (η1 rpm) at 1 rpm rotation (shear rate 2 s-1) and viscosity (η10 rpm) at 10 rpm rotation (shear rate 20 s-1) are measured, and the former is divided by the latter to give a TI value (η1 rpm / η10 rpm) Was calculated.
　［比抵抗］
　分散性、スプレー性及び保存安定性が「○」であった導電膜形成剤のみ評価対象とした。導電膜形成剤をガラス基板に１０ｍｍ×２６ｍｍの矩形状に膜厚１００～２００μｍでバーコーター塗布し、１５０℃の熱風乾燥機中で１０分、２００℃の熱風乾燥機中で６０分加熱し、導電膜を形成した。形成した導電膜の膜厚を表面粗さ計（株式会社東京精密製サーフコム４８０Ａ）で、常温（２５℃）での電気抵抗を電気抵抗測定装置（株式会社三
菱化学アナリティック社製低抵抗率計ロレスタＧＰ、四端子四探針法）で測定し、それら膜厚と電気抵抗と導電膜のアスペクト比に基づいて比抵抗（体積抵抗率）を算出して評価した。 [Resistivity]
Only conductive film forming agents whose dispersibility, sprayability and storage stability were “◯” were evaluated. A conductive film forming agent was applied to a glass substrate in a 10 mm × 26 mm rectangular shape with a bar coater having a film thickness of 100 to 200 μm, heated in a hot air dryer at 150 ° C. for 10 minutes, and heated in a hot air dryer at 200 ° C. for 60 minutes, A conductive film was formed. The film thickness of the formed conductive film was measured with a surface roughness meter (Surfcom 480A manufactured by Tokyo Seimitsu Co., Ltd.), and the electrical resistance at room temperature (25 ° C.) was measured with an electrical resistance measuring device (low resistivity meter manufactured by Mitsubishi Chemical Analytical Co., Ltd.) (Loresta GP, four-terminal four-probe method), and the specific resistance (volume resistivity) was calculated and evaluated based on the film thickness, electrical resistance, and aspect ratio of the conductive film.
　［製造例１：ＣＮＦ分散体１の調製］
　針葉樹パルプ２ｇに、水１５０ｍｌ、臭化ナトリウム０．２５ｇ、２，２，６，６－テトラメチルピペリジノオキシラジカル（ＴＥＭＰＯ）０．０２５ｇを加え、充分撹拌して分散させた後、１３質量％次亜塩素酸ナトリウム水溶液（共酸化剤）を、上記パルプ１．０ｇに対して次亜塩素酸ナトリウム量が１２．０ｍｍｏｌ／ｇとなるように加え、反応を開始した。反応の進行に伴いｐＨが低下するため、ｐＨを１０～１１に保持するように０．５Ｎ水酸化ナトリウム水溶液を滴下しながら、ｐＨの変化が見られなくなるまで反応した（反応時間：１２０分）。反応終了後、遠心分離機で固液分離し、純水を加えて固形分濃度４質量％に調整した。その後、２４質量％ＮａＯＨ水溶液にてスラリーのｐＨを１０に調整した。スラリーの温度を３０℃として水素化ホウ素ナトリウムをセルロース繊維に対して０．２ｍｍｏｌ／ｇ加え、２時間反応させることで還元処理した。反応後、０．１Ｎ塩酸を添加して中和した後、ろ過と水洗を繰り返して精製し、変性セルロース繊維を得た。この変性セルロース繊維にメタノールを加えてろ過し、メタノール洗浄を繰り返して、変性セルロース繊維に含まれる水をメタノールに置換した。その後、メタノールと、変性セルロース繊維のカルボキシル基量と等量のポリエーテルアミン（ＰＯ／ＥＯベースのモノアミン、ＪＥＦＦＡＭＩＮＥ　Ｍ－２０７０、ＨＵＮＴＳＭＡＮ社製）とを加えて、セルロース繊維濃度を２．５質量％になるように希釈し、高圧ホモジナイザー（スギノマシン社製、スターバースト）を用いて圧力１００ＭＰａで１回処理し、ゲル状組成物（ＣＮＦ分散体１）を得た。 [Production Example 1: Preparation of CNF dispersion 1]
After adding 150 ml of water, 0.25 g of sodium bromide, 0.025 g of 2,2,6,6-tetramethylpiperidinooxy radical (TEMPO) to 2 g of softwood pulp, 13 masses after being sufficiently stirred and dispersed. % Sodium hypochlorite aqueous solution (co-oxidant) was added so that the amount of sodium hypochlorite was 12.0 mmol / g with respect to 1.0 g of the pulp, and the reaction was started. Since the pH decreased with the progress of the reaction, the reaction was continued until no change in pH was observed while dropping a 0.5N aqueous sodium hydroxide solution so that the pH was maintained at 10 to 11 (reaction time: 120 minutes). . After completion of the reaction, solid-liquid separation was performed with a centrifuge, and pure water was added to adjust the solid content concentration to 4% by mass. Thereafter, the pH of the slurry was adjusted to 10 with a 24 mass% NaOH aqueous solution. The slurry was reduced to 30 ° C. by adding 0.2 mmol / g of sodium borohydride to the cellulose fiber and reacting for 2 hours. After the reaction, 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing to obtain modified cellulose fibers. Methanol was added to the modified cellulose fiber and filtered, and methanol washing was repeated to replace the water contained in the modified cellulose fiber with methanol. Thereafter, methanol and a polyetheramine (PO / EO-based monoamine, JEFFAMINE M-2070, manufactured by HUNTSMAN) in an amount equivalent to the carboxyl group amount of the modified cellulose fiber were added to adjust the cellulose fiber concentration to 2.5% by mass. Was diluted with a high pressure homogenizer (Sugino Machine, Starburst) at a pressure of 100 MPa to obtain a gel composition (CNF dispersion 1).
　得られたＣＮＦ分散体１は、メタノールを分散媒とするＴＥＭＰＯ酸化セルロースナノファイバーの２．５質量％分散体であり、セルロースナノファイバーのカルボキシル基の含有量は２．１ｍｍｏｌ／ｇ、数平均繊維径は４ｎｍであり、Ｉ型結晶構造を有するものであった。 The obtained CNF dispersion 1 is a 2.5 mass% dispersion of TEMPO-oxidized cellulose nanofibers using methanol as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 2.1 mmol / g, the number average fiber. The diameter was 4 nm and had an I-type crystal structure.
　［製造例２：ＣＮＦ分散体２の調製］
　針葉樹パルプ２ｇに、水１５０ｍｌ、臭化ナトリウム０．２５ｇ、ＴＥＭＰＯ０．０２５ｇを加え、充分撹拌して分散させた後、１３質量％次亜塩素酸ナトリウム水溶液（共酸化剤）を、上記パルプ１．０ｇに対して次亜塩素酸ナトリウム量が１２．０ｍｍｏｌ／ｇとなるように加え、反応を開始した。反応の進行に伴いｐＨが低下するため、ｐＨを１０～１１に保持するように０．５Ｎ水酸化ナトリウム水溶液を滴下しながら、ｐＨの変化が見られなくなるまで反応した（反応時間：１２０分、反応温度：４０℃）。反応終了後、０．１Ｎ塩酸を添加して中和した後、ろ過と水洗を繰り返して精製し、純水を加えて固形分濃度４質量％に調整した。その後、２４質量％ＮａＯＨ水溶液にてスラリーのｐＨを１０に調整した。スラリーの温度を３０℃として水素化ホウ素ナトリウムをセルロース繊維に対して０．２ｍｍｏｌ／ｇ加え、２時間反応させることで還元処理した。反応後、０．１Ｎ塩酸を添加して中和した後、ろ過と水洗を繰り返して精製し、変性セルロース繊維を得た。この変性セルロース繊維にＮ－メチルピロリドン（ＮＭＰ）を加えてろ過し、ＮＭＰ洗浄を繰り返して、変性セルロース繊維に含まれる水をＮＭＰに置換した。その後、ＮＭＰと、変性セルロース繊維のカルボキシル基量の３／４等量のポリエーテルアミン（ＪＥＦＦＡＭＩＮＥ　Ｍ－２００５、ＨＵＮＴＳＭＡＮ社製）と１／４等量のポリエーテルアミン（ＪＥＦＦＡＭＩＮＥ　Ｍ－２０７０、ＨＵＮＴＳＭＡＮ社製）を加えて、セルロース繊維濃度を９．０質量％になるように希釈し、高圧ホモジナイザー（スギノマシン社製、スターバースト）を用いて圧力１００ＭＰａで１回処理し、ゲル状組成物（ＣＮＦ分散体２）を得た。 [Production Example 2: Preparation of CNF dispersion 2]
After adding 150 ml of water, 0.25 g of sodium bromide, and 0.025 g of TEMPO to 2 g of softwood pulp, and thoroughly stirring and dispersing, 13% by mass sodium hypochlorite aqueous solution (co-oxidant) was added to the pulp 1. The reaction was started by adding sodium hypochlorite to 12.0 mmol / g with respect to 0 g. Since the pH decreased with the progress of the reaction, the reaction was performed while adding a 0.5N aqueous sodium hydroxide solution dropwise so that the pH was maintained at 10 to 11 until no change in pH was observed (reaction time: 120 minutes, Reaction temperature: 40 ° C.). After completion of the reaction, 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing with water, and pure water was added to adjust the solid content concentration to 4% by mass. Thereafter, the pH of the slurry was adjusted to 10 with a 24 mass% NaOH aqueous solution. The slurry was reduced to 30 ° C. by adding 0.2 mmol / g of sodium borohydride to the cellulose fiber and reacting for 2 hours. After the reaction, 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing to obtain modified cellulose fibers. N-methylpyrrolidone (NMP) was added to the modified cellulose fiber and filtered, and NMP washing was repeated to replace the water contained in the modified cellulose fiber with NMP. Then, NMP, 3/4 equivalent amount of polyetheramine (JEFFAMINE M-2005, manufactured by HUNTSMAN) and 1/4 equivalent amount of polyetheramine (JEFFAMINE M-2070, HUNTSMAN) The product is diluted to a cellulose fiber concentration of 9.0% by mass, treated once with a high-pressure homogenizer (Sugino Machine, Starburst) at a pressure of 100 MPa, and a gel composition (CNF Dispersion 2) was obtained.
　得られたＣＮＦ分散体２は、ＮＭＰを分散媒とするＴＥＭＰＯ酸化セルロースナノファイバーの９．０質量％分散体であり、セルロースナノファイバーのカルボキシル基の含有量は１．８ｍｍｏｌ／ｇ、数平均繊維径は４ｎｍであり、Ｉ型結晶構造を有するものであった。 The obtained CNF dispersion 2 is a 9.0 mass% dispersion of TEMPO-oxidized cellulose nanofibers using NMP as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 1.8 mmol / g, the number average fiber. The diameter was 4 nm and had an I-type crystal structure.
　［比較製造例１：ＣＮＦ分散体３の調製］
　針葉樹パルプ２ｇに、水１５０ｍｌ、臭化ナトリウム０．２５ｇ、ＴＥＭＰＯ０．０２５ｇを加え、充分撹拌して分散させた後、１３質量％次亜塩素酸ナトリウム水溶液（共酸化剤）を、上記パルプ１．０ｇに対して次亜塩素酸ナトリウム量が１２ｍｍｏｌ／ｇとなるように加え、反応を開始した。反応の進行に伴いｐＨが低下するため、ｐＨを１０～１１に保持するように０．５Ｎ水酸化ナトリウム水溶液を滴下しながら、ｐＨの変化が見られなくなるまで反応させた（反応時間：１２０分）。反応終了後、０．１Ｎ塩酸を添加して中和した後、ろ過と水洗を繰り返して精製し、繊維表面が酸化されたセルロース繊維を得た。つぎに、このセルロース繊維に純水を加えて２質量％に希釈し、高圧ホモジナイザー（三和エンジニアリング製、Ｈ１１）を用いて圧力１００ＭＰａで１回処理することにより、ゲル状組成物（ＣＮＦ分散体３）を製造した。 [Comparative Production Example 1: Preparation of CNF Dispersion 3]
After adding 150 ml of water, 0.25 g of sodium bromide, and 0.025 g of TEMPO to 2 g of softwood pulp, and thoroughly stirring and dispersing, 13% by mass sodium hypochlorite aqueous solution (co-oxidant) was added to the pulp 1. The reaction was started by adding sodium hypochlorite so that the amount of sodium hypochlorite was 12 mmol / g with respect to 0 g. Since the pH decreased with the progress of the reaction, the reaction was continued until no change in pH was observed while dropping a 0.5N aqueous sodium hydroxide solution so that the pH was maintained at 10 to 11 (reaction time: 120 minutes). ). After completion of the reaction, 0.1N hydrochloric acid was added for neutralization, followed by purification by repeated filtration and washing to obtain cellulose fibers having oxidized fiber surfaces. Next, pure water is added to this cellulose fiber to dilute it to 2% by mass, and it is treated once at a pressure of 100 MPa using a high-pressure homogenizer (manufactured by Sanwa Engineering Co., Ltd., H11), whereby a gel composition (CNF dispersion) is obtained. 3) was produced.
　得られたＣＮＦ分散体３は、水を分散媒とするＴＥＭＰＯ酸化セルロースナノファイバーの２．０質量％分散体であり、セルロースナノファイバーのカルボキシル基の含有量は２．１ｍｍｏｌ／ｇ、数平均繊維径は４ｎｍであり、Ｉ型結晶構造を有するものであった。 The obtained CNF dispersion 3 is a 2.0 mass% dispersion of TEMPO oxidized cellulose nanofibers using water as a dispersion medium, and the carboxyl group content of the cellulose nanofibers is 2.1 mmol / g, the number average fiber. The diameter was 4 nm and had an I-type crystal structure.
　［実施例１：導電膜形成剤の調製］
　フレーク状銀粉末（商品名：シルコートＡｇＣ－Ａ、福田金属箔粉工業（株）製、比表面積０．６～０．９ｍ２／ｇ、５０％平均粒子径４．６５μｍ）０．９５質量部と、製造例１で得られたＣＮＦ分散体１（メタノールを分散媒とするＴＥＭＰＯ酸化セルロースナノファイバーの２．５質量％分散体）２．００質量部を、ガラス製容器に測り取り、自転公転ミキサー（ＥＭＥ社製、Ｖ－ｍｉｎｉ３００）を用いて１５００ｒｐｍで５分間混合を行い、実施例１に係る導電膜形成剤を得た。 [Example 1: Preparation of conductive film forming agent]
Flaky silver powder (trade name: SILCOAT AgC-A, manufactured by Fukuda Metal Foil Powder Co., Ltd., specific surface area 0.6 to 0.9 m 2 / g, 50% average particle size 4.65 μm) 0.95 parts by mass Then, 2.00 parts by mass of CNF dispersion 1 (2.5% by mass dispersion of TEMPO-oxidized cellulose nanofiber using methanol as a dispersion medium) obtained in Production Example 1 was measured in a glass container, and rotation and revolution Mixing was performed at 1500 rpm for 5 minutes using a mixer (manufactured by EME, V-mini300) to obtain a conductive film forming agent according to Example 1.
　実施例１の導電膜形成剤において、銀粉とセルロースナノファイバーとの混合比率（固形分中での各含有率）は、銀粉９５質量％、セルロースナノファイバー５質量％である。 In the conductive film forming agent of Example 1, the mixing ratio of silver powder and cellulose nanofibers (each content in the solid content) is 95% by mass of silver powder and 5% by mass of cellulose nanofibers.
　［実施例２，比較例１～７］
　各成分の種類と配合量を下記表１に示す通りにしたこと以外は、実施例１と同様に導電膜形成剤を調製した。実施例２及び比較例１～７の導電膜形成剤ではいずれも、銀粉とセルロースナノファイバー又はバインダ樹脂との固形分での混合比率が、銀粉９５質量％、セルロースナノファイバー又はバインダ樹脂５質量％であった。 [Example 2, Comparative Examples 1 to 7]
A conductive film forming agent was prepared in the same manner as in Example 1 except that the types and blending amounts of the components were as shown in Table 1 below. In any of the conductive film forming agents of Example 2 and Comparative Examples 1 to 7, the mixing ratio of silver powder and cellulose nanofiber or binder resin in the solid content was 95% by mass of silver powder, and 5% by mass of cellulose nanofiber or binder resin. Met.
　表中のバインダ樹脂１，２は以下の通りである。
・バインダ樹脂１：エポキシ樹脂、商品名：アデカレジンＥＰ－４９０１Ｅ、株式会社ＡＤＥＫＡ製
・バインダ樹脂２：エチルセルロース、商品名：エチルセルロース　粘度：８０～１２０ｃｐｓ（５％溶液，２５℃）、ナカライテスク製 The binder resins 1 and 2 in the table are as follows.
Binder resin 1: Epoxy resin, trade name: Adeka Resin EP-4901E, manufactured by ADEKA Corporation Binder resin 2: ethyl cellulose, trade name: ethyl cellulose Viscosity: 80-120 cps (5% solution, 25 ° C.), manufactured by Nacalai Tesque
　得られた実施例１，２及び比較例１～７の導電膜形成剤について、分散性、スプレー性、保存安定性、ＴＩ値、及び比抵抗の評価を行った。結果は表１に示す通りである。なお、比較例１、３、７は分散性の良好な導電膜形成剤が得られなかったため分散性以外の評価は不可能であった。 The conductive film forming agents obtained in Examples 1 and 2 and Comparative Examples 1 to 7 were evaluated for dispersibility, sprayability, storage stability, TI value, and specific resistance. The results are as shown in Table 1. In Comparative Examples 1, 3, and 7, it was impossible to evaluate other than dispersibility because a conductive film forming agent having good dispersibility could not be obtained.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１から明らかなように、有機溶媒を分散媒としてセルロースナノファイバーを含有させた実施例１，２の導電膜形成剤であると、銀粉の分散性に優れ、チクソ性（ＴＩ）が高く、良好な保存安定性を有するとともにスプレー塗布が可能であった。また、導電膜形成剤から得られる導電膜は、比抵抗が低く良好な導電性を示した。 As is clear from Table 1, the conductive film forming agent of Examples 1 and 2 containing cellulose nanofibers using an organic solvent as a dispersion medium has excellent dispersibility of silver powder and high thixotropy (TI). It had good storage stability and could be sprayed. In addition, the conductive film obtained from the conductive film forming agent had low specific resistance and good conductivity.
　これに対して、実施例１，２におけるセルロースナノファイバーをバインダ樹脂１（エポキシ樹脂）に置き換えた比較例１，３では分散不良となり銀粉が沈降した。比較例１，３の導電膜形成剤では実施例１，２に対して粘度がかなり低いものであったため、粘度を高めるべく比較例２，４のように有機溶媒量を減量したところ、分散性及び保存安定性は改善したものの、スプレー性は良好でなかった。 In contrast, Comparative Examples 1 and 3 in which the cellulose nanofibers in Examples 1 and 2 were replaced with binder resin 1 (epoxy resin) resulted in poor dispersion and silver powder settled. Since the viscosity of the conductive film forming agent of Comparative Examples 1 and 3 was considerably lower than that of Examples 1 and 2, when the amount of the organic solvent was reduced as in Comparative Examples 2 and 4 to increase the viscosity, dispersibility Although the storage stability was improved, the sprayability was not good.
　セルロースナノファイバーの代わりに有機溶剤に可溶なエチルセルロースを用いた比較例５，６では、銀粉の分散は可能であったが、スプレー性又は保存安定性が劣っており、スプレー性と保存安定性を両立できなかった。 In Comparative Examples 5 and 6 using ethyl cellulose soluble in an organic solvent instead of cellulose nanofibers, silver powder could be dispersed, but sprayability or storage stability was poor, and sprayability and storage stability I could not balance.
　また、比較例７のようにセルロースナノファイバーの水分散体を用いた場合、銀粉の分散性が悪化した。 In addition, when an aqueous dispersion of cellulose nanofiber was used as in Comparative Example 7, the dispersibility of the silver powder deteriorated.
　以上、本発明のいくつかの実施形態を説明したが、これら実施形態は、例として提示したものであり、発明の範囲を限定することは意図していない。これら実施形態は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更を行うことができる。これら実施形態やその省略、置き換え、変更などは、発明の範囲や要旨に含まれると同様に、特許請求の範囲に記載された発明とその均等の範囲に含まれるものである。 Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their omissions, replacements, changes, and the like are included in the inventions described in the claims and their equivalents as well as included in the scope and gist of the invention.

Claims (6)

  1. 　下記の（Ａ）～（Ｃ）成分を含有することを特徴とする導電膜形成剤。
    （Ａ）銀粉及び／又は銀コート粉
    （Ｂ）セルロースナノファイバー
    （Ｃ）有機溶媒     A conductive film forming agent comprising the following components (A) to (C):
    (A) Silver powder and / or silver-coated powder (B) Cellulose nanofiber (C) Organic solvent
  2. 　前記（Ａ）成分が５０％平均粒子径１００ｎｍ以上の銀粉及び／又は銀コート粉である、請求項１に記載の導電膜形成剤。 The conductive film forming agent according to claim 1, wherein the component (A) is a silver powder and / or a silver-coated powder having a 50% average particle diameter of 100 nm or more.
  3. 　分散媒としての水を実質的に含まない、請求項１又は２に記載の導電膜形成剤。 The conductive film forming agent according to claim 1 or 2, which substantially does not contain water as a dispersion medium.
  4. 　前記（Ａ）成分と（Ｂ）成分の含有量の合計１００重量％に対する（Ａ）成分の含有量が７０～９８質量％である、請求項１～３のいずれか１項に記載の導電膜形成剤。 The conductive film according to any one of claims 1 to 3, wherein the content of the component (A) is 70 to 98% by mass relative to the total content of the components (A) and (B) of 100% by weight. Forming agent.
  5. 　スプレー用である、請求項１～４のいずれか１項に記載の導電膜形成剤。 The conductive film forming agent according to any one of claims 1 to 4, which is used for spraying.
  6. 　請求項１～５のいずれか１項に記載の導電膜形成剤を塗布してなる導電膜。 A conductive film obtained by applying the conductive film forming agent according to any one of claims 1 to 5.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009076455A (en) * 2007-08-30 2009-04-09 Mitsuboshi Belting Ltd Conductive substrate and its manufacturing method
JP2010196150A (en) * 2009-02-27 2010-09-09 Dowa Electronics Materials Co Ltd Metal nanoparticle dispersion and method for producing metal film
JP2016017161A (en) * 2014-07-10 2016-02-01 京都エレックス株式会社 Composition for forming inorganic particle-containing functional film, and method for producing electronic device using the same

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009076455A (en) * 2007-08-30 2009-04-09 Mitsuboshi Belting Ltd Conductive substrate and its manufacturing method
JP2010196150A (en) * 2009-02-27 2010-09-09 Dowa Electronics Materials Co Ltd Metal nanoparticle dispersion and method for producing metal film
JP2016017161A (en) * 2014-07-10 2016-02-01 京都エレックス株式会社 Composition for forming inorganic particle-containing functional film, and method for producing electronic device using the same

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