CN113795557A - Conductive composition, conductive film, contact member, and method for producing conductive composition - Google Patents
Conductive composition, conductive film, contact member, and method for producing conductive composition Download PDFInfo
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- CN113795557A CN113795557A CN202080033864.7A CN202080033864A CN113795557A CN 113795557 A CN113795557 A CN 113795557A CN 202080033864 A CN202080033864 A CN 202080033864A CN 113795557 A CN113795557 A CN 113795557A
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- 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
- H01B1/24—Conductive material dispersed in non-conductive organic material the conductive material comprising carbon-silicon compounds, carbon or silicon
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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
- C09D11/00—Inks
- C09D11/02—Printing inks
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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
- C09D11/00—Inks
- C09D11/02—Printing inks
- C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
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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
- C09D11/00—Inks
- C09D11/02—Printing inks
- C09D11/10—Printing inks based on artificial resins
- C09D11/102—Printing inks based on artificial resins containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds
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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
- C09D11/00—Inks
- C09D11/52—Electrically conductive inks
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- 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
- H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
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- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/021—Composite material
- H01H1/027—Composite material containing carbon particles or fibres
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/06—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
- H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
Abstract
Provided are a conductive composition having a lower resistance than conventional ones, a conductive film, a contact member, and a method for producing the conductive composition. The conductive composition comprises an elastomer, multilayer graphene having a major diameter of 5 [ mu ] m or more and 100 [ mu ] m or less and a thickness of 5nm or more and 30nm or less, and a conductive filler. The conductive film is formed of the conductive composition and constitutes a contact portion of the contact member. The method for producing the conductive composition includes a step of mixing a liquid composition containing a conductive filler and a solvent, and a step of mixing an elastomer and multilayer graphene into the liquid composition.
Description
Technical Field
The present invention relates to a conductive composition used for a contact rubber switch or the like, a conductive film, a contact member, and a method for producing a conductive composition.
Background
Conventionally, a contact rubber switch as a contact member is disposed on an electrode of a wiring provided on a circuit board, the contact member has a conductive contact portion, and the electrode is connected to the conductive contact portion to perform an input operation such as turning on and off. For example, a contact member or a contact rubber switch formed with a conductive film made of conductive ink is used.
Jp 61-245417 a (patent document 1) discloses a method of forming a conductive portion by dropping conductive ink on a contact rubber conductive portion.
Jp 2000 a-113759 a (patent document 2) discloses a method for manufacturing a conductive part by transferring conductive ink onto a cover member molded from an elastic material.
In any of the documents, a conductive ink is used, but the components thereof are not described.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 61-245417
Patent document 2: japanese patent laid-open publication No. 2000-113759
Disclosure of Invention
Problems to be solved by the invention
It is desired that the resistance of a conductive film obtained by applying a conductive ink (conductive composition) is low. In particular, in a contact rubber switch used in an in-vehicle device, since a large current flows through a wiring of a circuit board, a contact member for connecting electrodes has a large electric load and is preferably low in resistance.
Means for solving the problems
In order to achieve the above object, the present invention has the following features.
That is, the conductive composition of the present invention is characterized by comprising an elastomer, multilayer graphene and a conductive filler, wherein the average major axis of the multilayer graphene is 5 μm or more and 100 μm or less, and the average thickness of the multilayer graphene is 5nm or more and 100nm or less.
The conductive film obtained using the conductive composition of the present invention can have a lower resistance, particularly a lower volume resistivity, than conventional ones.
In the conductive composition of the present invention, the elastomer may be a thermosetting liquid silicone elastomer.
By using a thermosetting liquid silicone elastomer as the elastomer, the strength and key durability of the conductive film obtained by using the conductive composition of the present invention as a contact member are improved as compared with the case of using another elastomer.
In the conductive composition of the present invention, the conductive filler can be conductive carbon black.
By using the conductive carbon black as the conductive filler, the conductive film obtained by using the conductive composition of the present invention can have a lower resistance, particularly a lower volume resistivity, than a conventional conductive film, due to a synergistic effect of the combination of the multilayer graphene and the conductive carbon black.
In the electrically conductive composition of the present invention, the BET (Brunauer, Emmett, Teller) specific surface area of the multilayer graphene may be 20m2More than 35 m/g2The ratio of the carbon atoms to the carbon atoms is less than g.
By making BET specific surface area of the multilayer graphene 15m240m above g2In terms of/gNext, the conductive film obtained using the conductive composition of the present invention can have a significantly lower resistance than conventional ones, and in particular, can have a significantly lower volume resistivity.
The conductive film of the present invention is formed from the conductive composition of the present invention (i.e., the conductive composition according to any one of claims 1 to 4).
The conductive film is formed from the conductive composition of the present invention, and thus the resistance of the conductive film can be made smaller than before, and particularly the volume resistivity can be made smaller.
In a cross section obtained by cutting the conductive film of the present invention in a vertical direction, an average distance between adjacent multilayer graphene layers may be 0.01 μm or more and 10 μm or less.
In a cross section obtained by cutting the conductive film in a vertical direction, the average distance between the multi-layer graphene layers is 0.01 μm or more and 10 μm or less, whereby the multi-layer graphene layers are close to each other, and therefore, the conductivity between the multi-layer graphene layers can be obtained. As a result, the resistance of the conductive film can be reduced as compared with the conventional one.
In a cross section obtained by cutting the conductive film of the present invention in a vertical direction, the multi-layer graphene may be dispersed and arranged in a substantially layered manner.
In a cross section obtained by cutting the conductive film in a vertical direction, the multilayer graphene is dispersed and arranged in a substantially layered manner, and thus, the conductivity in the surface direction of the conductive film is particularly improved as compared with a case where the multilayer graphene is not dispersed and arranged in a substantially layered manner.
In a cross section obtained by cutting the conductive film of the present invention in a vertical direction, the plurality of layers of graphene can intersect with each other and are alternately arranged in a dispersed manner.
In a cross section obtained by cutting the conductive film in the vertical direction, the multilayer graphene is arranged so as to intersect with each other and alternately disperse, and thus, the conductivity in the thickness direction of the conductive film is particularly improved as compared with a case where the multilayer graphene is not arranged so as to intersect with each other and alternately disperse.
In the conductive film of the present invention, the volume resistivity may be 0.1 Ω · cm or more and 2.0 Ω · cm or less.
By setting the volume resistivity of the conductive film to the above range, the resistance of the conductive film becomes smaller than that of the conventional one.
The contact member of the present invention is characterized in that the contact portion has the conductive film of the present invention (i.e., the conductive film according to any one of claims 5 to 9).
The contact member has the conductive film of the present invention in the contact portion, and thus the resistance of the conductive portion of the contact member can be made smaller than before, and particularly the volume resistivity can be made smaller.
The method for producing a conductive composition of the present invention is characterized by comprising a step of mixing a liquid composition containing a conductive filler and a solvent, and a step of mixing an elastomer and multilayer graphene into the liquid composition.
According to the method for producing the conductive composition of the present invention having the above steps, the conductive composition can be mixed at an appropriate viscosity in each step. Thereby, the finally obtained conductive composition becomes a uniform component.
In the method for producing a conductive composition of the present invention, when the conductive filler is conductive carbon black, the content of the conductive carbon black is 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed, and the content of the multilayer graphene is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed.
In the method for producing the conductive composition, when the conductive filler is conductive carbon black, the conductive carbon black is dispersed among the multilayer graphene by setting the content of the conductive carbon black and the content of the multilayer graphene to the above range, and the conductivity of the conductive film obtained from the conductive composition is improved.
Effects of the invention
According to the conductive composition of the present invention, the resistance can be made lower than that of a conventional conductive composition. In addition, the conductive film of the present invention can have a lower resistance than conventional ones. In addition, the contact member of the present invention can make the resistance of the contact portion lower than that of the conventional contact member. In addition, the method for producing a conductive composition of the present invention can provide a conductive composition having low conductivity and excellent uniformity.
Drawings
Fig. 1 is a Scanning Electron Microscope (SEM) image of a cross section of a conductive film according to an example of the present invention in a vertical direction.
Fig. 2 is an enlarged SEM image of the white quadrangular portion shown in fig. 1.
Fig. 3 is a flowchart illustrating a method for producing the conductive composition of the present invention.
Detailed Description
[ conductive composition ]
The present invention will be described in detail based on embodiments. The conductive composition of the present invention comprises an elastomer, multilayer graphene, and a conductive filler, and is characterized in that the average major diameter of the multilayer graphene is 5 [ mu ] m or more and 100 [ mu ] m or less, and the average thickness of the multilayer graphene is 5nm or more and 100nm or less.
In the present invention, "multilayer graphene" refers to a laminate of at least two or more layers of graphene other than single-layer graphene. Single-layer graphene is a single layer having a thickness of 1 atom which is exfoliated from Graphite (Graphite) having a multilayer structure, and six-membered rings of carbon atoms are connected to form a planar structure. The "multilayer graphene" in the present specification is formed by stacking several to several hundreds of single layers of graphene, and the number of stacked layers is smaller than that of Graphite (Graphite) particles. The term "multilayer graphene" in the present specification includes commercially available materials generally referred to as "multilayer graphene" and commercially available materials generally referred to as "thin-layer graphene" or "few-layer graphene" or "multilayer graphene".
Next, the structure of the conductive composition of the present invention will be described in detail.
< elastomer >
Examples of the elastomer used in the conductive composition of the present invention include crosslinked rubbers such as silicone rubber (silicone rubber), natural rubber, isoprene rubber, butadiene rubber, acrylonitrile butadiene rubber, 1, 2-polybutadiene, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, epichlorohydrin rubber, fluororubber, and urethane rubber, and thermoplastic elastomers such as styrene thermoplastic elastomers, olefin thermoplastic elastomers, ester thermoplastic elastomers, polyurethane thermoplastic elastomers, amide thermoplastic elastomers, vinyl chloride thermoplastic elastomers, and fluorine thermoplastic elastomers. Among these materials, silicone rubber is preferable in view of its small compression set as a contact member, its close adhesion, its key durability, and its small change in properties at high or low temperatures (environmental resistance). In addition, a thermosetting liquid silicone elastomer (silicone elastomer) is preferable in view of processability for producing the conductive composition and the conductive film.
< multilayer graphene >
The average major diameter of the multilayer graphene is 5 μm to 100 μm, preferably 10 μm to 100 μm, and more preferably 10 μm to 30 μm, from the viewpoint of reducing the electrical resistance of the conductive film obtained using the conductive composition. If the average major axis of the multilayer graphene is less than 5 μm, it is necessary to add a large amount of the multilayer graphene, and the conductive composition becomes high in viscosity, resulting in deterioration of workability. On the other hand, if the average major axis of the multilayer graphene exceeds 100 μm, the average major axis may exceed the thickness of the conductive film and be exposed from the surface of the conductive film. In addition, the average thickness of the multilayer graphene is 5nm to 100nm, preferably 10nm to 30nm, from the viewpoint of reducing the resistance of the conductive film obtained using the conductive composition. If the average thickness of the multilayer graphene is less than 5nm, it is similar to that of single-layer graphene, and thus the conductivity is low. On the other hand, when the average thickness of the multilayer graphene exceeds 100nm, the aspect ratio becomes small and the conductivity is low.
In the present specification, the "average major axis of multilayer graphene" is determined in the following manner. That is, the same conductive film obtained using the conductive composition was cut in four different directions in the vertical direction to obtain four cross sections. Next, four cross sections are photographed by a scanning electron microscope (hereinafter, abbreviated as "SEM") to obtain four SEM images. Regarding the major axes of each of the 100 multi-layer graphene observed through the four SEM images, the first 10% in order from the long major axis is assumed as the longest axis, and the average of the longest axes of the multi-layer graphene between the four SEM images is defined as "average major axis of the multi-layer graphene". The "average major axis of graphene in the cross section of the conductive film" in the examples described below was also determined in the same manner as described above.
In the present specification, the "average thickness of multilayer graphene" is determined in the following manner. That is, the same conductive film obtained using the conductive composition was cut in four different directions in the vertical direction to obtain four cross sections. Next, the four cross sections were photographed by a Scanning Electron Microscope (SEM), and four SEM images were obtained. The thicknesses of 100 pieces of multi-layer graphene observed from these four SEM images were measured, and the average value of the thicknesses of 400 pieces of multi-layer graphene in total was defined as "average thickness of multi-layer graphene". The "average thickness of graphene in a cross section of the conductive film" in the following examples was also determined in the same manner as described above.
The oil absorption of the multilayer graphene is preferably 2.5cc/g to 4.5cc/g, and more preferably 2.5cc/g to 3.5cc/g, from the viewpoint of reducing the electrical resistance and increasing the strength of a conductive film obtained using the conductive composition. Wherein the oil absorption is measured according to JIS K5101-13-1: 2004(ISO 787-5: 1980). If the oil absorption amount is too large, the solvent, oil, low molecular weight components in the elastomer, and the like in the conductive composition are easily adsorbed, and the conductive composition cannot be aggregated in an ink form, which is not preferable. The strength of the obtained conductive film is also low.
The BET specific surface area of the multilayer graphene is preferably 15m from the viewpoint of reducing the resistance of a conductive film obtained using the conductive composition and bringing the conductive composition to a predetermined viscosity in view of workability240m above g2A ratio of 20m or less per gram2More than 35 m/g2The ratio of the carbon atoms to the carbon atoms is less than g. Wherein the BET specific surface area is as defined in JIS Z8830: 2013(ISO 9277: 2010). The method of measuring the adsorbed gas may be a carrier gas method, and the adsorption data may be analyzed by a one-point method. When the BET specific surface area of the graphene is too large, the solvent, oil, and low molecular weight components in the elastomer are easily adsorbed, and the conductive composition cannot be aggregated in an ink form, which is not preferable. The strength of the obtained conductive film is also low. When the specific surface area of the single-layer graphene is large, the oil absorption tends to be large.
< conductive Filler >
From the viewpoint of reducing the electrical resistance of the conductive film obtained by using the conductive composition, examples of the conductive filler include silver, copper, gold, silver-plated copper, bimetallic powder, graphite particles, carbon nanotubes, conductive carbon black or other carbon allotropes, other metals, metal oxides, or conductive powders thereof, and these may be used alone or in combination of two or more. From the viewpoint of making the electrical resistance of the conductive film lower by combining with the multilayer graphene, conductive carbon black is preferable as the conductive filler. Examples of the conductive carbon black include acetylene black, ketjen black, other furnace black, channel black, and thermal black. In addition, in the present specification, the conductive filler does not contain multilayer graphene.
The conductive carbon black preferably has a BET specific surface area of 10m from the viewpoint of reducing the electrical resistance of a conductive film obtained using the conductive composition and bringing the conductive composition to a predetermined viscosity in view of workability21300m above g2A ratio of 30m or less per gram2300m above g2The ratio of the carbon atoms to the carbon atoms is less than g. Wherein the BET specific surface area is as defined in JIS Z8830: 2013(ISO 9277: 2010).
[ conductive film ]
The conductive film of the present invention is formed from the conductive composition of the present invention.
Fig. 1 shows an SEM image obtained by taking a cross section of a conductive film 10 according to an example of the present invention in a vertical direction by SEM. In addition, fig. 2 shows an enlarged SEM image of the white quadrangle portion shown in fig. 1. Hereinafter, description will be given with reference to fig. 1 and 2.
The conductive film 10 according to one embodiment of the present invention includes an elastomer 30, multilayer graphene 20a and 20b, and a conductive filler 40. Here, the multilayer graphene extending in the direction along the plane of the conductive film 10 is 20a, and the multilayer graphene extending in the thickness direction is 20 b. The elastomer 30, the multilayer graphene 20a, 20b, and the conductive filler 40 are the same as those described in the above conductive composition, and therefore, the description thereof is omitted here. In fig. 2, a black line-shaped crack is observed in the cross section of the conductive film 10, and it is understood that the multilayer graphene 20a and 20b extends along the crack.
In a cross section formed by cutting the conductive film 10 in the vertical direction, the average values of the distances (open double-headed arrows shown in fig. 2) between adjacent multilayer graphene sheets 20a, 20b, and 20a and 20b are preferably 0.01 μm to 10 μm, and more preferably 0.05 μm to 10 μm, respectively. The average distance between the multilayer graphene in the conductive film of the present invention is an average value of distances between 100 adjacent multilayer graphene viewed from one direction of the conductive film in a vertical cross section in an SEM image.
In the above cross section, the average distance (the hollow double-headed arrow shown in fig. 2) between the multilayer graphenes 20a, 20b, and 20a, 20b is 0.01 μm or more and 10 μm or less, and therefore the multilayer graphenes 20a, 20b, and 20a, 20b are close to each other. This makes it possible to obtain conductivity between the multilayer graphenes 20a, between the multilayer graphenes 20b, and between the multilayer graphenes 20a and 20 b. As a result, the resistance of the conductive film 10 can be reduced compared to the conventional one.
As shown in fig. 2, in a cross section obtained by cutting the conductive film 10 in the vertical direction, the graphene layers 20a extend in a direction along the plane of the conductive film 10 and are dispersed in a substantially laminar manner. In the cross section obtained by cutting the conductive film 10 in the vertical direction, the multilayer graphene 20a is dispersed and arranged in a substantially laminar manner, and therefore, the conductivity in the surface direction of the conductive film 10 is particularly improved as compared with the case where the multilayer graphene is not dispersed in a substantially laminar manner.
As shown in fig. 2, in a cross section obtained by cutting the conductive film 10 in the vertical direction, the graphene layers 20a and 20b intersect with each other and are alternately arranged in a dispersed manner. In a cross section obtained by cutting the conductive film 10 in the vertical direction, the multilayer graphene 20a and 20b intersect with each other and are alternately arranged in a dispersed manner, and therefore, the conductivity in the thickness direction of the conductive film 10 is particularly improved as compared with the case where the multilayer graphene is not intersected but is alternately arranged in a dispersed manner.
The volume resistivity of the conductive film 10 is preferably 0.1 Ω · cm to 2.0 Ω · cm, more preferably 0.3 Ω · cm to 1.8 Ω · cm, and further preferably 0.3 Ω · cm to 1.3 Ω · cm. The volume resistivity was measured in accordance with JIS K7194-1994. The details of the measurement are described in examples described later.
In the case where the conductive filler of the conductive film of the present invention is conductive carbon black, the content of the conductive carbon black is preferably 10 parts by mass or more and 80 parts by mass or less, more preferably 30 parts by mass or more and 60 parts by mass or less, and still more preferably 40 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the conductive composition excluding the conductive carbon black and the multilayer graphene, from the viewpoint of improving conductivity. In addition, from the viewpoint of improving conductivity, when the conductive filler of the conductive film of the present invention is conductive carbon black, the content of the multilayer graphene is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 15 parts by mass or more and 50 parts by mass or less, and still more preferably 20 parts by mass or more and 50 parts by mass or less, with respect to 100 parts by mass of the conductive composition excluding the conductive carbon black and the multilayer graphene.
[ contact Member ]
In the contact member of the present invention, the contact portion includes the conductive film of the present invention. Conventionally, a contact rubber switch, which is a contact member having a conductive contact portion, has been used.
The contact member includes a main body and a contact portion, and is formed using an elastic body. The contact portion becomes conductive by having a conductive film on the surface of the contact portion. As the elastomer, the same material (for example, silicone rubber) as the elastomer used in the above-mentioned conductive composition can be used.
[ method for producing conductive composition ]
As shown in fig. 3, the method for producing a conductive composition of the present invention is characterized by comprising a step (S100) of mixing a liquid composition containing a conductive filler, a solvent, and a dispersant, and a step (S102) of mixing an elastomer and multilayer graphene into the liquid composition.
By producing the conductive composition in the above-described order of steps, the conductive filler and the multilayer graphene can be mixed and mixed in different steps, and therefore, the increase in viscosity can be suppressed as compared with a case where the conductive filler and the multilayer graphene are mixed in the same step. Further, since the conductive filler and the elastomer can be mixed in different steps, an increase in viscosity can be suppressed as compared with a case where the conductive filler and the elastomer are mixed in the same step. As a result, in each of the steps, since mixing can be performed at an appropriate viscosity, the finally obtained conductive composition can be made into a uniformly dispersed component. Other compounding agents may be contained, and a dispersant or the like may be used. For example, the conductive composition can be produced by the following steps: the method includes a step (S100) of mixing a liquid composition containing a conductive filler, a solvent, and a dispersant, and a step (S102) of mixing an elastomer and multilayer graphene into the liquid composition.
In the method for producing the conductive composition, when the conductive filler is conductive carbon black, the content of the conductive carbon black is preferably 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed, and the content of the multilayer graphene is preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed.
In the method for producing the conductive composition, when the conductive filler is conductive carbon black, the conductive carbon black is dispersed between the multilayer graphene by setting the contents of the conductive carbon black and the multilayer graphene to the above ranges, and thus the conductivity of the conductive film obtained from the conductive composition is improved.
Examples
Next, the present invention will be described in further detail based on examples (comparative examples).
< preparation of sample >
First sample:
50 parts by mass of a conductive carbon black having a trade name of "# 3030B" (manufactured by Mitsubishi chemical corporation), 160 parts by mass of a cycloalkane solvent as a solvent, and 8.2 parts by mass of a fatty acid ester dispersant as a dispersant were mixed, and the mixture was stirred with a vibration stirrer for 1 minute, followed by filtration through a screen to obtain a liquid composition.
A commercial product "iGurafen- α S" (long diameter: 3 to 30 μm, thickness: 10nm, BET specific surface area 27 m) as "multilayer graphene 1" was blended in the liquid composition2(iv)/g, oil absorption: 2.5 to 3.5cc/g, manufactured by iTEC corporation) and 100 parts by mass of a silicone rubber as an elastomer, which was sold under the trade name "ELATOSIL (registered trademark) LR 6250F" (manufactured by Wacker ChemieAG), were stirred with the vibration stirrer for 3 minutes. To 100 parts by mass of the obtained semi-finished product, 130 parts by mass of an aliphatic hydrocarbon solvent as a diluent solvent was added, and to 100 parts by mass of "ELATOSIL (registered trademark) LR 6250F", 10 parts by mass of a curing agent having a trade name of "Wacker (registered trademark) Crosslinker 525" was added, and the mixture was stirred at 600 to 700rpm for 20 minutes using a propeller stirrer to obtain a mixtureTo conductive composition 1.
Next, the conductive composition 1 was applied to the surface of a PET substrate by a bar coating method, and then heated at 150 ℃ for 1 hour to dry the coating film and perform a crosslinking reaction, thereby producing a conductive film 1 having a thickness of 30 μm.
Second to fifth samples:
in the first sample, the amounts of the multilayer graphene and the conductive carbon black used in the first sample were changed as shown in table 1, and the materials were mixed by the same preparation method as the first sample to obtain conductive compositions 2 to 5, respectively. Then, conductive films 2 to 5 were produced in the same manner as in example 1.
Sixth to tenth samples:
the commercial product "iGurafen- α S" as the multilayer graphene 1 used in the first sample was changed to the commercial product "iGurafen- α" as the "multilayer graphene 2" (long diameter: 10 to 100 μm, thickness: 10nm, BET specific surface area 20 to 27 m)2(iv)/g, oil absorption: 4.5cc/g, manufactured by iTEC corporation), and the amounts of the multilayer graphene and the conductive carbon black were changed as shown in table 2, and mixed by the same preparation method as the first sample to obtain conductive compositions 6 to 10, respectively. Then, conductive films 6 to 10 were produced in the same manner as in example 1.
Eleventh to thirteenth samples:
the commercial product "iGurafen-Alpha S" as the multilayer graphene 1 used in the first sample was changed to the commercial product "N006-P" (long diameter: 5 μm, thickness: 10 to 20nm, BET specific surface area 15 m) as the thin-layer graphene2(ii)/g or more, manufactured by angstromata nasialimited), and the amount of the thin-layer graphene blended was changed as shown in table 3, and the mixture was mixed by the same preparation method as the first sample, to obtain conductive compositions 11 to 13, respectively. Then, conductive films 11 to 13 were produced in the same manner as in example 1.
Fourteenth to sixteenth samples:
the commercial product "iGurafen- α S" used as the multilayer graphene 1 in the first sample was changed to the commercial product "N008-N" (long diameter: 5 μm, thickness) used as the few-layer graphene: 50 to 100nm, a BET specific surface area of 30m2(ii)/g or less, manufactured by angstromata assialimited), and the amount of the few-layer graphene blended was changed as shown in table 4, and the mixture was mixed by the same preparation method as the first sample to obtain conductive compositions 14 to 16, respectively. Then, conductive films 14 to 16 were produced in the same manner as in example 1.
Seventeenth sample:
the commercial product "iGurafen-Alpha S" as the multilayer graphene 1 used in the first sample was changed to the commercial product "N002-PDR" (long diameter: 10 μm or less, thickness: 1nm, BET specific surface area 400 to 500 m) as the single-layer graphene2(v/g, manufactured by australia side limited), and the amount of the thin-layer graphene blended was changed as shown in table 5, and mixed by the same preparation method as the first sample, to obtain the conductive composition 17. Then, a conductive film 17 was produced in the same manner as in example 1.
Eighteenth sample:
as shown in table 5, the conductive composition 18 was obtained by mixing in the same production method as the first sample except that the multilayer graphene used in the first sample was not contained and other graphene was not contained, and 50 parts by mass of a trade name "# 3030B" (manufactured by mitsubishi chemical corporation) as a conductive carbon black used in the first sample and 20 parts by mass of a trade name "XN-100" (manufactured by japan graphite fiber corporation) as a carbon fiber were blended as a conductive filler. Then, a conductive film 18 was produced in the same manner as in example 1.
Nineteenth sample:
the conductive composition 19 was obtained by mixing the first sample in the same manner as the first sample except that 20 parts by mass of a product name "XN-100" (manufactured by japan graphite fiber co., ltd.) of carbon fiber was further blended as a conductive filler. Then, a conductive film 19 was produced in the same manner as in example 1.
Twentieth test piece:
as shown in table 5, the conductive composition 20 was obtained by mixing the first sample in the same production method except that the multilayer graphene used in the first sample was not included and other graphene was not included, and 50 parts by mass of a trade name "# 3030B" (manufactured by mitsubishi chemical corporation) of conductive carbon black used in the first sample and 2.5 parts by mass of a trade name "JENOTUBE 8A" (manufactured by yokohami trade venture corporation) of carbon nanotubes used as the conductive filler were blended as the conductive filler. Then, a conductive film 20 was produced in the same manner as in example 1.
Twenty-first sample:
the conductive composition 21 was obtained by mixing the first sample in the same manner as the first sample except that 2.5 parts by mass of a product name "JENOTUBE 8A" (product of gayowa trade yokko) of carbon nanotubes was further added as a conductive filler. Then, a conductive film 21 was produced in the same manner as in example 1.
< various measuring methods, tests and evaluations >
Measurement of volume resistivity:
the volume resistivity of the produced conductive film was measured. The volume resistivity was measured in accordance with JIS K7194-1994. The measurement was carried out using a device having a trade name "Loresta GP" (manufactured by Mitsubishi chemical analysis, Ltd.). The thickness of the conductive film (test piece) is 20 to 30 μm.
Average major axis of graphene in cross section of conductive film:
the same conductive film was cut in four different directions in the vertical direction to obtain four cross sections. Next, the four cross sections were photographed by a Scanning Electron Microscope (SEM), and four SEM images were obtained. The major axes of 100 pieces of graphene observed from the four SEM images were measured, and the first 10% in order from the major axis was assumed as the longest axis, and the average value of the longest axes of the multilayer graphene between the four SEM images was defined as "the average major axis of graphene in the cross section of the conductive film". Here, "graphene" is a generic name of multilayer graphene, thin-layer graphene, few-layer graphene, and single-layer graphene.
Average thickness of graphene in cross section of conductive film:
the same conductive film was cut in four different directions in the vertical direction to obtain four cross sections. Next, four cross sections were photographed by SEM, and four SEM images were obtained. The thicknesses of 100 pieces of graphene observed from these four SEM images were measured, and the average value of the thicknesses of a total of 400 pieces of graphene was defined as "the average thickness of graphene in the cross section of the conductive film". As described above, "graphene" is a generic name of multilayer graphene, thin-layer graphene, few-layer graphene, and single-layer graphene.
Average distance between graphene in the conductive film:
the average distance between the graphenes in the conductive film is an average value of distances between 100 adjacent graphenes observed from the conductive film in a vertical cross section in an SEM image. As described above, graphene is a generic name of multilayer graphene, thin-layer graphene, few-layer graphene, and single-layer graphene.
[ Table 1]
[ Table 2]
[ Table 3]
[ Table 4]
[ Table 5]
< analysis of test results >
From the results of the first to sixteenth samples, it was found that the amount of graphene blended was large, and the volume resistivity of the conductive film was low. Further, the results of the first to tenth samples show that the conductive carbon black is large and the volume resistance of the conductive film is low.
The following effects can be observed from the results of the first to seventeen samples: the volume resistivity of the conductive film formed by blending thin-layer graphene, few-layer graphene, or multi-layer graphene 1 and 2 is lower than that of single-layer graphene. From the results of the first to fourteenth samples, it was found that the volume resistivity of the conductive film was lowered in the order of the single-layer graphene, the thin-layer graphene, the few-layer graphene, the multi-layer graphene 2, and the multi-layer graphene 1 blended therein.
From the results of the first, eighteenth, and twentieth samples, it is understood that the volume resistivity of the conductive film not containing graphene is high. From the results of the eighteenth, nineteenth, twentieth, and twenty-first samples, it is found that the volume resistivity of the conductive film is significantly reduced in both the case where carbon fibers as the conductive filler are added to the conductive carbon black and the case where carbon nanotubes as the conductive filler are added to the conductive carbon black and the case where the conductive carbon black is blended with the carbon fibers by blending the multi-layer graphene.
From the results of the first to sixteenth samples, it is found that the volume resistivity of the conductive film is approximately decreased as the average distance between the graphenes in the conductive film is decreased
Description of the reference numerals
10 a conductive film,
20a, 20b multilayer graphene,
30 an elastic body,
40 conductive filler.
Claims (12)
1. An electrically conductive composition comprising an elastomer, multilayer graphene and an electrically conductive filler, wherein the average major diameter of the multilayer graphene is 5 μm or more and 100 μm or less, and the average thickness of the multilayer graphene is 5nm or more and 100nm or less.
2. The conductive composition according to claim 1, wherein the elastomer is a thermosetting liquid silicone elastomer.
3. The electrically conductive composition of claim 1 or 2, wherein the electrically conductive filler is electrically conductive carbon black.
4. The conductive composition according to any one of claims 1 to 3, wherein the BET specific surface area of the multilayer graphene is 15m240m above g2The ratio of the carbon atoms to the carbon atoms is less than g.
5. A conductive film formed from the conductive composition according to any one of claims 1 to 4.
6. The conductive film according to claim 5, wherein an average distance between adjacent multilayer graphene layers is 0.01 μm or more and 10 μm or less in a cross section cut in a vertical direction.
7. The conductive film according to claim 5 or 6, wherein the multilayer graphene is dispersed and arranged in substantially a layer shape in a cross section cut in a vertical direction.
8. The conductive film according to claim 5 or 6, wherein the multilayer graphene crosses each other and is alternately arranged in a dispersed manner in a cross section cut in a vertical direction.
9. The conductive film according to any one of claims 5 to 8, wherein the volume resistivity is 0.1 Ω -cm or more and 2.0 Ω -cm or less.
10. A contact member comprising the conductive film according to any one of claims 5 to 9 in a contact portion.
11. A method for producing a conductive composition, comprising:
a step of mixing a liquid composition containing a conductive filler and a solvent; and
and a step of mixing an elastomer and multilayer graphene into the liquid composition.
12. The method for producing an electrically conductive composition according to claim 11,
in the case where the conductive filler is conductive carbon black,
the content of the conductive carbon black is 10 to 80 parts by mass with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed,
the content of the multilayer graphene is 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the conductive composition from which the conductive carbon black and the multilayer graphene are removed.
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| PCT/JP2020/022918 WO2021019923A1 (en) | 2019-07-30 | 2020-06-10 | Conductive composition, conductive film, contact member and method for producing conductive composition |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102906015A (en) * | 2011-02-09 | 2013-01-30 | 创业发展联盟技术有限公司 | Method for producing multilayer graphene coated substrate |
| CN105209385A (en) * | 2013-05-15 | 2015-12-30 | 昭和电工株式会社 | Flaky graphite containing boron and production method therefor |
| WO2018135540A1 (en) * | 2017-01-19 | 2018-07-26 | 出光興産株式会社 | Graphene composition, method for producing same, and conductive film |
| CN108885919A (en) * | 2016-03-30 | 2018-11-23 | 住友理工株式会社 | Conductive film and preparation method thereof |
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| JPS61245417A (en) | 1985-04-24 | 1986-10-31 | 富士ポリマテック株式会社 | Formation of contact rubber conducting section |
| JP3476372B2 (en) | 1998-10-05 | 2003-12-10 | 信越ポリマー株式会社 | Method and apparatus for manufacturing cover member for push button switch |
| JP5872964B2 (en) * | 2012-05-29 | 2016-03-01 | 東レ・ダウコーニング株式会社 | Conductive room temperature curable fluorosilicone rubber composition |
| JP6273948B2 (en) * | 2014-03-24 | 2018-02-07 | 日本ゼオン株式会社 | Conductive adhesive composition for electrochemical element electrode, current collector with adhesive layer, and electrode for electrochemical element |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102906015A (en) * | 2011-02-09 | 2013-01-30 | 创业发展联盟技术有限公司 | Method for producing multilayer graphene coated substrate |
| CN105209385A (en) * | 2013-05-15 | 2015-12-30 | 昭和电工株式会社 | Flaky graphite containing boron and production method therefor |
| CN108885919A (en) * | 2016-03-30 | 2018-11-23 | 住友理工株式会社 | Conductive film and preparation method thereof |
| WO2018135540A1 (en) * | 2017-01-19 | 2018-07-26 | 出光興産株式会社 | Graphene composition, method for producing same, and conductive film |
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| WO2021019923A1 (en) | 2021-02-04 |
| DE112020002761T5 (en) | 2022-03-03 |
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