WO2017141982A1 - Multi-walled carbon nanotube–containing composition and production method therefor, and production method for single-walled and/or double-walled carbon nanotube–containing composition - Google Patents

Abstract

Provided are a multi-walled CNT–containing composition that has excellent conductivity and excellent stability of the conductive properties over time, and a production method therefor. Additionally provided is a production method for a doped single-walled and/or double-walled CNT–containing composition whereby it is possible to produce a CNT–containing composition having excellent conductivity and resistance stability in a high temperature environment. The production method for the multi-walled CNT–containing composition includes a contact step for bringing a 2-coordinate boron cation salt into contact with multi-walled carbon nanotubes comprising at least 35% carbon nanotubes having three or more layers, with 100% being the total number of carbon nanotubes.

Description

Multi-walled carbon nanotube-containing composition and method for producing the same, and method for producing single-walled and / or double-walled carbon nanotube-containing composition

The present invention relates to a multi-walled carbon nanotube-containing composition and a method for producing the same. The present invention also relates to a method for producing a single-walled and / or double-walled carbon nanotube-containing composition.

Carbon nanotubes (hereinafter also referred to as CNTs) are about half as light as aluminum, yet have about 20 times the strength of steel, excellent elasticity, and excellent conductivity, so a wide range R & D is actively promoted in the field. According to the layer structure, it is roughly classified into a single layer (single wall) and a multilayer (multiwall), and the characteristics are different from each other. Single-walled CNTs have a substantially cylindrical shape by rolling one sheet of graphite. Multi-walled CNTs are multi-layered CNTs, and multi-walled CNTs in particular are two-layered CNTs. . CNTs themselves have excellent intrinsic conductivity. Multi-walled CNTs have mechanical strength equivalent to that of diamond, and have excellent conductivity and elasticity.

Due to the excellent conductivity of CNT, for example, it is expected to be used for wiring of semiconductor circuits, vias, electrodes for fuel cells, conductive composites, solar cells, secondary battery electrodes, electronic paper, various sensors, etc. . In addition, transparent conductors using CNTs are known. The CNT is obtained as a mixture of metallic CNT and semiconducting CNT at the time of synthesis. If semiconducting CNT can be changed to metallic CNT, CNT can be easily used as a conductive material.

From such a background, a method of changing semiconducting CNTs to metallic CNTs by doping has been proposed. Specifically, a method for improving the conductivity of CNTs by doping nitric acid into CNTs is disclosed (Non-Patent Document 1). Non-patent documents 2 to 4 will be described later.

However, there is a problem that it is difficult to maintain the doping effect over time.

The present invention has been made in view of the above background, and a first object of the present invention is to provide a multi-walled carbon nanotube-containing composition having excellent electrical conductivity and excellent temporal stability of conductive properties, and a method for producing the same. The second object is to provide a method for producing a single-walled and / or double-walled carbon nanotube-containing composition capable of producing a carbon nanotube-containing composition that is excellent in conductivity and resistance value stability in a high-temperature environment. Is to provide.

As a result of extensive studies by the present inventors, it has been found that the problems of the present invention can be solved in the following modes, and the present invention has been completed.

[1]: A method for producing a multi-walled carbon nanotube-containing composition, comprising a contact step of contacting a carbon nanotube with a two-coordinate boron cation salt, wherein the total number of the carbon nanotubes is 100%. Sometimes, a method for producing a multi-walled carbon nanotube-containing composition containing 35% or more of three or more layers of carbon nanotubes.
[2]: The two-coordinate boron cation is represented by the following general formula (1)

[Wherein R ¹ and R ² are each independently a phenyl group, a mesityl group, a 1,5-dimethylphenyl group, a 1,3,5-triisopropylphenyl group, a 1,5-diisopropylphenyl group, 1, It is a compound selected from the group consisting of 3,5-tris (trifluoromethyl) phenyl group and 1,5-bis (trifluoromethyl) phenyl group. ]
[1] The method for producing a multi-walled carbon nanotube-containing composition according to [1].
[3]: The counter anion of the two-coordinate boron cation salt includes at least one of a fluorine-based anion and a carborane derivative, and the fluorine-based anion includes BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenylborate, tetrakis It is at least one selected from the group consisting of (pentafluorophenyl) borate, and the carborane derivative is monocarbacrode decaborate (HCB ₁₁ H ₁₁ ⁻ ), monocarba crosound decachlorododecaborate ( The method for producing a multi-walled carbon nanotube-containing composition according to [1] or [2], which is at least one selected from the group consisting of HCB ₁₁ Cl ₁₁ ⁻ ).
[4]: The contact step includes (i) coating the carbon nanotube on a substrate, and contacting the obtained coating film and the two-coordinate boron cation salt, (ii) the carbon nanotube and the (Iii) including at least one selected from the step of mixing the carbon nanotube powder and the powder of the bicoordinate boron cation salt [1] to [3] The method for producing a multi-walled carbon nanotube-containing composition according to any one of [3].
[5]: It includes multi-walled carbon nanotubes and a counter anion of a two-coordinate boron cation salt, and the multi-walled carbon nanotubes have 35% or more of three or more layers of carbon nanotubes when the total number of carbon nanotubes is 100%. Including
The counter anion includes at least one of a fluorine-based anion and a carborane derivative, and the fluorine-based anion is selected from the group consisting of BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenyl borate, and tetrakis (pentafluorophenyl) borate. And the carborane derivative is selected from the group consisting of monocarbacrode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and monocarbacrosoundecachlorododecaborate (HCB ₁₁ Cl ₁₁ ⁻ ). A composition comprising at least one multi-walled carbon nanotube.
[6] The multi-walled carbon nanotube-containing composition according to [5], further comprising a resin.
[7]: A method for producing a single-walled and / or double-walled carbon nanotube-containing composition,
When the total number of carbon nanotubes is 100%, single-walled carbon nanotubes and / or double-walled carbon nanotubes containing 70% or more of single-walled carbon nanotubes and / or double-walled carbon nanotubes are brought into contact with the bicoordinate boron cation salt. Including a contact step,
A method for producing a single-walled and / or double-walled carbon nanotube-containing composition.
[8]: The two-coordinate boron cation is represented by the following general formula (1):

[Wherein R ¹ and R ² are each independently a phenyl group, a mesityl group, a 1,5-dimethylphenyl group, a 1,3,5-triisopropylphenyl group, a 1,5-diisopropylphenyl group, 1, It is a compound selected from the group consisting of 3,5-tris (trifluoromethyl) phenyl group and 1,5-bis (trifluoromethyl) phenyl group. ]
[7] The method for producing a single-walled and / or double-walled carbon nanotube-containing composition according to [7].
[9]: The counter anion of the two-coordinate boron cation salt includes at least one of a fluorine-based anion and a carborane derivative,
The fluorine-based anion is at least one selected from the group consisting of BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenyl borate, tetrakis (pentafluorophenyl) borate,
The carborane derivative is at least one selected from the group consisting of monocarbar crosode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and mono carb crosound undecachloro dodecaborate (HCB ₁₁ Cl ₁₁ ⁻ ) [ [7] A method for producing a single-walled and / or double-walled carbon nanotube-containing composition according to [8].
[10]: The contact step includes
(I) coating the single-walled and / or double-walled carbon nanotube-containing material on a substrate, and coating the obtained bicoordinate boron cation salt on the resulting coating film [7] A method for producing a single-walled and / or double-walled carbon nanotube-containing composition according to any one of [9] to [9].

According to the present invention, it is possible to provide a carbon nanotube-containing composition that is excellent in electrical conductivity and stability over time of conductive characteristics, and has an excellent effect. Further, it is possible to provide a method for producing a doped single-walled and / or double-walled carbon nanotube-containing composition capable of producing a CNT-containing composition that is excellent in conductivity and resistance value stability in a high-temperature environment. It has the effect.

^{_{Et 3 Si + [(C 6}} F 5) 4 B] shows the chemical formula of ^one mesitylene adduct. Mes ₂ B ⁺ is a diagram showing a _{[(C 6 F 5) 4} B] ^one formula.

Hereinafter, an example of an embodiment to which the present invention is applied will be described. Needless to say, other embodiments are also included in the scope of the present invention as long as they meet the spirit of the present invention. Moreover, the numerical value specified in this specification is a value calculated | required by the method disclosed by embodiment.

[First Embodiment]
The method for producing a multi-walled carbon nanotube-containing composition according to the first embodiment includes a contacting step in which a multi-coordinate boron cation salt is brought into contact with the multi-walled carbon nanotube. The multi-walled carbon nanotube according to the first embodiment includes 35% or more of multi-walled carbon nanotubes of three or more layers, where the total number of carbon nanotubes is 100%. Hereinafter, the carbon nanotube may be abbreviated as CNT.

CNTs are broadly classified into single layers (single wall) and multilayers (multiwall) according to the layer structure. In the first embodiment, as described above, when the total number of CNTs is 100%, three or more layers are included. A multilayer CNT containing 35% or more of CNT is used. Such multilayer CNTs can be produced by a gas phase flow method, an arc discharge method, a catalyst-supported vapor phase growth method, or the like. Commercially available multilayer CNTs may be used. For example, VGCF-H (registered trademark, manufactured by Showa Denko KK) can be exemplified.

In this specification, the ratio of three or more layers in the multi-walled CNT was determined as follows. That is, a coating film of a multilayer CNT-containing composition is formed, and this is directly observed with a transmission electron microscope. Single-layer, double-layer, and three-layer or more CNTs in a certain region (region where at least 100 can be observed) The ratio of the number of CNTs having three or more layers to the above was determined. In the case of a composition in which the multilayer CNT-containing composition is dispersed or dissolved in a solvent, it is appropriately diluted, formed a coating film, removed the solvent, and then directly observed with a transmission electron microscope. Similarly, the ratio of the number of CNTs having three or more layers was determined. At this time, the solvent may be substituted if necessary. Moreover, you may observe using a high-resolution transmission electron microscope. Other components contained in the CNT-containing composition may be measured without being removed or removed during the measurement.

The bi-coordinate boron cation salt is added as a doping agent to the multilayer CNT. The two-coordinate boron cation in the two-coordinate boron cation salt functions as a strong oxidant. That is, when the bi-coordinate boron cation salt is brought into contact with the multilayer CNT, the bi-coordinate boron cation of the bi-coordinate boron cation salt functions as an oxidizing agent for the multi-wall CNT, and holes are formed in the multi-wall CNT. Thereby, the electroconductivity of multilayer CNT can be improved. Further, the counter anion of the bicoordinate boron cation salt is present as an anion counter around the multilayer CNT in which holes are formed. As a result, it is possible to improve the temporal stability of the conductive properties of the multilayer CNT.

Although the 2-coordinate boron cation is not particularly limited, preferred examples of the coordination group of the 2-coordinate boron cation include a phenyl group, a mesityl group (1,3,5-trimethylphenyl group), 1,5- Dimethylphenyl group, 1,3,5-triisopropylphenyl group, 1,5-diisopropylphenyl group, 1,3,5-tris (trifluoromethyl) phenyl group, 1,5-bis (trifluoromethyl) phenyl group A group having at least one selected from the group consisting of

Preferable examples of the bicoordinate boron cation include a compound represented by the following general formula (1).

In the formula, R ¹ and R ² are each independently a phenyl group, mesityl group, 1,5-dimethylphenyl group, 1,3,5-triisopropylphenyl group, 1,5-diisopropylphenyl group, 1,3 , 5-tris (trifluoromethyl) phenyl group and 1,5-bis (trifluoromethyl) phenyl group.

The counter anion that forms a salt with the bicoordinate boron cation is preferably at least one of a fluorine-based anion and a carborane derivative. Examples of the fluorine-based anion include at least one selected from the group consisting of BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenyl borate, and tetrakis (pentafluorophenyl) borate. Examples of the carborane derivative include at least one selected from the group consisting of monocarbar crosode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and mono carber crosound undecachloro dodecaborate (HCB ₁₁ Cl ₁₁ ⁻ ). it can.

As the solvent for dissolving the 2-coordinate boron cation salt, a solvent that does not react with the boron cation is used. For example, nonpolar solvents such as orthodichlorobenzene, 1,2,4-trichlorobenzene and mesitylene are preferred.

The bicoordinate boron cation salt can be synthesized, for example, using the methods of Non-Patent Documents 1 to 3. For example, a dimesitylborinium ion Mes ₂ B ⁺ (HCB ₁₁ Cl ₁₁ ⁻ ) having a monocarburose undecachlorododecaborate represented by the formula (2) as a counter anion can be synthesized by the following method. .

First, in a glove box in which oxygen and water concentrations are each controlled to be 0.1 ppm or less under an argon or nitrogen atmosphere, monocarburound undecachlorododecaborate salt [Et ₃ Si ⁺ (HCB ₁₁ Cl _{11 ^-)]} (fluoro dimethyl cytidine Ruboran) in dry o-dichlorobenzene solution of the non-Patent Document 2) at room temperature, the mixture is stirred for 5 minutes at 25 ° C.. The reaction solution is distilled off under reduced pressure and concentrated to about 0.5 mL. By introducing hexane vapor into the obtained reaction mixture by a vapor diffusion method, colorless transparent crystals are deposited. The crystals are collected by filtration and washed with dry hexane to obtain [Mes ₂ B ⁺ (HCB ₁₁ Cl ₁₁ ⁻ )] as colorless and transparent crystals.

Further, the dimesitylborinium ion Mes ₂ B ⁺ [(C ₆ F ₅ ) ₄ B ⁻ ] having tetrakis (pentafluorophenyl) borate as a counter anion is Mes ₂ B ⁺ (HCB ₁₁ Cl ₁₁ ⁻ ). By using a mesitylene adduct of Et ₃ Si ⁺ [(C ₆ F ₅ ) ₄ B ⁻ ] in place of Et ₃ Si ⁺ (HCB ₁₁ Cl ₁₁ ⁻ ) (see Non-Patent Document 3) Mes ₂ B ⁺ [(C ₆ F ₅ ) ₄ B ⁻ ] is obtained as colorless transparent crystals.

As described above, the method for producing a multilayer CNT-containing composition of the first embodiment includes a contact step in which a bi-coordinate boron cation salt is brought into contact with the multilayer CNT. The contacting step may be any method as long as the multi-walled CNT can be oxidized with the bi-coordinated boron cation and the counter-anion of the bi-coordinated boron cation salt can remain in the multi-walled CNT. Preferred examples include (i) to (iii) below.
(I) A multilayer CNT is coated on a substrate, and the obtained coating film is brought into contact with a two-coordinate boron cation salt.
(Ii) Multilayer CNT and a bicoordinate boron cation salt are mixed in a solvent.
(Iii) A multilayer CNT powder and a bicoordinate boron cation salt powder are mixed.
These steps are used alone or in combination.

As a method of the above (i), that is, a method of contacting a bicoordinate boron cation salt with a coating film of multi-layer CNT, a method such as a spin coating method, a dip coating method, an ink jet method, a printing method, a spray method, a dispenser method, etc. Can be illustrated. These coating methods may be used in combination.

As an example, a multi-walled CNT-containing composition not containing a bi-coordinated boron cation (in this specification, also referred to as a multi-walled CNT-containing composition before doping) or a multi-walled CNT is prepared, dissolved in a good solvent, and spin-coated. A coating film is obtained on a substrate using a method or the like. Next, a solution of a bicoordinate boron cation salt (for example, a saturated solution of orthocyclobenzene) is prepared, and the substrate with a coating film is immersed in the solution (for example, 1 minute). At this time, the bicoordinate boron cation functions as a strong oxidant, and holes are formed in the multilayer CNT. Accordingly, the counter anion of the bicoordinate boron cation salt functions as a counter anion of the multilayer CNT. The bicoordinate boron cation used as the oxidant is removed along with the solution. You may add a washing | cleaning process as needed. Thereafter, it is dried at room temperature or by heating. Through these steps, a coating film comprising a multi-walled CNT-containing composition in which the counter-anion of the bicoordinate boron cation salt remains in the coating film is obtained.

The base material used for the coating film is appropriately selected from glass and resin according to the purpose and needs. When mechanical strength and transparency are required, glass is suitable, and (meth) acrylate resin and the like are suitable for applications that require transparency. A base material is comprised from a single or several laminated body.

The following method can be exemplified as the method of (ii) above, that is, the method of contacting by mixing in a solvent. As the multi-walled CNT, for example, a commercially available product such as VGCF-H (registered trademark, manufactured by Showa Denko) is prepared and dissolved in a good solvent. Examples of the solvent include orthodichlorobenzene. Next, a bicoordinate boron cation salt is added thereto and mixed. The doping concentration is not particularly limited, but is, for example, 0.01 to 30 mM. Through these steps, a multilayer CNT-containing composition doped with a counter-anion of a bicoordinate boron cation salt is obtained. The obtained multilayer CNT-containing composition can be formed into a film by coating, or can be molded by injection molding, extrusion molding, or sheet molding.

The above method (iii), that is, the method of mixing the powder of the multilayer CNT and the powder of the two-coordinate boron cation salt may be uniformly mixed using a mixer. In this case, the bicoordinate boron cation oxidizes the multi-walled CNT and remains as a neutral compound, but does not affect the conductivity and stability over time. If a step of dissolving in a solvent is performed at the time of thin film formation or the like, most of it is removed. Note that the multilayer CNT powder and the powder of the two-coordinate boron cation salt to be used may be subjected to an airflow pulverization treatment or the like as necessary. Further, when mixing the powder, a method of mixing other compounds together, or a method of mixing the pre-dope multi-walled CNT-containing composition already mixed with the multi-walled CNT etc. and the bicoordinate boron cation salt may be used. .

In addition to the multilayer CNT and the counter-anion of the two-coordinate boron cation salt, other compounds can be added to the multilayer CNT-containing composition. Other compounds can be appropriately selected according to the purpose and needs. Suitable examples include resins and carbon fibers other than multilayer CNTs (for example, carbon black, ketjen black, milled carbon fiber). Further, a dispersant, an antifoaming agent, a plasticizer, an antioxidant, a binder, and the like may be added. Examples of the resin include a thermoplastic resin and a thermosetting resin containing a curable compound. Photosensitive resins and conductive resins are also preferably used.

Preferable examples include a composite material composed of a multilayer CNT-containing composition comprising a thermoplastic resin, a multilayer CNT, a counter-anion of a two-coordinate boron cation salt, a conductive polymer, a multilayer CNT, and a pair of two-coordinate boron cation salts. The composite material which consists of a multilayer CNT containing composition containing an anion is mentioned.

Thermoplastic resins include polystyrene, styrene / acrylonitrile copolymers, styrene / maleic anhydride copolymers, styrene (co) polymers such as (meth) acrylic acid ester / styrene copolymers; ABS resins, AES resins Rubber-reinforced resin such as ASA resin, MBS resin, HIPS resin; α-olefin (co) heavy comprising at least one α-olefin having 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene / propylene copolymer, etc. Olefin resins such as polymers and modified polymers thereof (chlorinated polyethylene, etc.), cyclic olefins (eg, norbornene) copolymers; ionomers such as polyacrylic acid, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers Ethylene copolymers such as polyvinyl chloride, ethylene / vinyl chloride Nyl polymer, vinyl chloride resin such as polyvinylidene chloride; (co) polymer acrylic resin using one or more (meth) acrylic acid esters such as polymethyl methacrylate (PMMA); polyamide 6, polyamide Polyamide resins (PA) such as 6,6 polyamide 612: Polyester resins such as polycarbonate (PC), polyethylene terephthalate (PET), polybutylene phthalate (PBT), polyethylene naphthalate: polyacetal resin (POM), polyphenylene ether ( PPE), polyarylate resin; fluororesin such as polytetrafluoroethylene and polyvinylidene fluoride: liquid crystal polymer; imide resin such as polyimide, polyamideimide, and polyetherimide: ketone resin such as polyetherketone; polysulfone, poly Urethane resins; sulfone-based resins such Terusuruhon polyvinyl acetate; polyethylene oxide: polyvinyl alcohol: polyvinyl ether: polyvinyl butyrate; phenoxy resins; photosensitive resin; biodegradable plastic and the like.

Of these thermoplastic resins, ABS resin, AES resin, ASA resin, AS resin, MBS resin, HIPS resin, polyethylene, polypropylene, polycarbonate (PC), polyphenylene ether (PPE), and polyamide (PA) are preferable. These can be used alone or in combination of two or more.

Moreover, in order to improve impact resistance, the thermoplastic resin composition in the first embodiment may contain other elastomer components. Elastomers used to improve impact properties include olefin elastomers such as EPR and EPDM, styrene elastomers such as SBR made of a copolymer of styrene and butadiene, silicone elastomers, nitrile elastomers, and butadiene elastomers. , Urethane elastomers, polyamide elastomers, ester elastomers, fluorine elastomers, natural rubbers, and modified products in which reaction sites (double bonds, carboxylic acid anhydride groups, etc.) are introduced into these elastomers can be used. . Moreover, a conductive polymer can be used as the resin, and the conductive characteristics can be expressed by the synergistic effect of the multilayer CNT and the conductive polymer.

Resin and multilayer CNT content ratio can be designed as appropriate according to needs. The content of the multilayer CNT with respect to the resin is, for example, 0.1 to 95% by mass.

According to the first embodiment, by doping bi-coordinate boron cation salt into multi-layer CNT, multi-layer CNT can be oxidized by bi-coordinate boron cation of bi-coordinate boron cation salt, and holes can be formed in multi-layer CNT. . For this reason, a conductive characteristic can be improved. Further, the stable counter anion of the bicoordinate boron cation salt remains around the multi-walled CNT in which holes are formed, so that thermal stability and environmental resistance can be improved.

An electrode material is suitable for the use of the multilayer CNT-containing composition. Further, it is useful for a semiconductor layer such as a thin film transistor substrate. It is also useful for a wide range of applications such as sensors, actuators, building materials, paints, CNT paper, and medical equipment.

[Second Embodiment]
In the second embodiment, single-layer and / or double-wall CNTs are used instead of the multi-layer CNTs defined in the first embodiment. Here, “single-layer and / or double-walled CNT-containing material” means a total of a plurality of CNTs. The existence form is not particularly limited. For example, they may exist independently, in a bundle form, in an intertwined form, or a mixed form thereof. In the present embodiment, the CNT-containing material and the CNT are substantially the same, and in this embodiment, the CNT-containing material may be simply referred to as CNT.

1st Embodiment and / or 2nd Embodiment and 2 coordination boron cation salt, an additive, a manufacturing method, etc. are applicable similarly except the point from which a composition of CNT differs.

The “single-layer and / or double-walled CNT-containing material” according to the second embodiment refers to one containing 70% or more of single-walled CNT and / or double-walled CNT out of the total number of CNTs. Single-walled CNTs are CNTs in which one surface of graphite is wound in one layer, and including 70% or more means that 70 or more of 100 CNTs are single-walled CNTs. The two-layer CNT is a CNT obtained by winding one surface of graphite into two layers, and including 70% or more means that 70 or more out of 100 CNTs are two-layer CNTs.

When 70% or more of single-walled CNTs and / or double-walled CNTs are included in the total number of CNTs, the conductivity of the CNTs becomes extremely high. More preferably, 75 or more of 100 are included, and most preferably 80 or more of 100 are included. In general, single-walled CNTs and / or double-walled CNTs have higher crystallinity, smaller diameter, and more contact points per unit amount of CNT in the conductive layer than multi-walled CNTs of three or more layers. The conductivity tends to be high.

The number of CNT layers can be measured, for example, by preparing a sample as follows. In the case where the CNT is a composition dispersed in a solvent such as a liquid, when the solvent is an aqueous system, the CNT-containing material is appropriately diluted with water to a concentration that can be easily seen, and is dropped by several μL onto the collodion film and air-dried. Thereafter, the CNT-containing material on the collodion film is directly examined with a transmission electron microscope image. On the other hand, when the solvent is non-aqueous, after removing the solvent by drying once, it is dispersed again in water, diluted as appropriate, dropped several μL onto the collodion film, air-dried, and a transmission electron microscope image is obtained. Observe. Further, when the CNT-containing material is not dispersed in the solvent, for example, the CNT-containing material can be extracted with a solvent and similarly observed with a high-resolution transmission electron microscope. The monolayer and / or bilayer CNT-containing material may contain catalyst particles and a dispersant.

In the present specification, the “single-layer and / or two-layer CNT-containing composition” contains a single-layer and / or two-layer CNT-containing material and at least a counter anion of a two-coordinate boron cation salt. That is, the single-layer and / or double-walled CNT-containing composition refers to a composition containing at least a doping component in the single-layer and / or double-walled CNT-containing material. The bicoordinate boron cation is represented by the following general formula (1), as in the first embodiment.

R ¹ and R ² are compounds selected from the same group as in the first embodiment. In addition, the counter anion of the two-coordinate boron cation salt can be exemplified by the same compounds as in the first embodiment.

As the bicoordinate boron cation salt, the above bicoordinate boron cation and a counter anion are used in combination. Among these, a combination of mesityl group (1,3,5-trimethylphenyl group) and tetrakis (pentafluorophenyl) borate is particularly preferable. The solvent used when dissolving the 2-coordinate boron cation salt is not particularly limited.

The method for bringing the monolayer and / or bilayer CNT-containing material into contact with the bicoordinate boron cation salt is not particularly limited. As a suitable example, the method of apply | coating a monolayer and / or 2 layer CNT containing material on a base material, and apply | coating a bicoordinate boron cation salt with respect to the obtained coating film can be illustrated. In these coatings, a solvent is appropriately used. Resin, glass, etc. can be illustrated as a raw material of the base material used for 2nd Embodiment. Examples of the resin include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), polyimide, polyphenylene sulfide, aramid, polypropylene, polyethylene, polylactic acid, polyvinyl chloride, Polymethyl methacrylate, alicyclic acrylic resin, cycloolefin resin, triacetyl cellulose, and the like can be used. As the glass, ordinary soda glass can be used. Moreover, these several base materials can also be used in combination.

The method for applying the single-layer and / or double-layer CNT-containing material on the substrate is not particularly limited, and known application methods such as spray coating, dip coating, spin coating, knife coating, kiss coating, gravure coating, slot die Coating, screen printing, inkjet printing, pad printing, other main types of printing, roll coating, and the like can be used. Moreover, application | coating may be performed in multiple times and you may combine two different types of application | coating methods.

The method for applying the bicoordinate boron cation salt onto the monolayer and / or the bilayer CNT-containing material is not particularly limited, and known application methods such as spray coating, dip coating, spin coating, screen printing, inkjet printing, pad Printing, printing of other main types, roll coating, or the like can be used. Moreover, application | coating may be performed in multiple times and you may combine two different types of application | coating methods.

The single layer and / or double layer CNT-containing composition of the second embodiment can be preferably used as an electrode material.

[Third Embodiment]
The “mixed CNT-containing composition” according to the third embodiment is defined in any definition of the multilayer CNT-containing composition according to the first embodiment and the single-layer and / or double-wall CNT-containing composition according to the second embodiment. It is defined to refer to a CNT-containing composition that is not included. That is, out of the total number of CNTs, the multi-layer CNTs according to the first embodiment are more than 30% and less than 35%, and the single-layer and / or two-layer CNTs according to the second embodiment are more than 65% and less than 70%. It refers to a certain CNT-containing composition.

According to the mixed CNT-containing composition according to the third embodiment, an electrode material is suitable. Further, it is useful for a semiconductor layer such as a thin film transistor substrate. It is also useful for a wide range of applications such as sensors, actuators, building materials, paints, CNT paper, and medical equipment.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The measurement method used in this example is shown below.
(1) Measuring method of the number of CNT layers Several microliters of CNTs were dropped on a collodion film and air-dried, and then observed with a transmission electron microscope at a magnification of 400,000 times. The number of layers was measured for 100 CNTs arbitrarily extracted from a visual field in which 10% or more of the visual field area was CNT in a 75 nm square visual field. When 100 lines could not be measured in one field of view, measurements were made from a plurality of fields until 100 lines were obtained. At this time, one CNT was counted as one if some CNTs were visible in the field of view. In addition, even if it is recognized as two in the field of view, it may be connected outside the field of view and become one, but in that case, it was counted as two.

(2) Resistance measurement method between terminals at 25 ° C. and humidity 30% RH In a small environmental tester (manufactured by Espec Co., Ltd., SH-221), with both electrodes of the conductive laminate with electrodes clipped, It was kept at a temperature of 25 ° C. and a humidity of 30% RH for 30 minutes. The inter-terminal resistance value in the small environmental tester was recorded every 30 seconds using a multi-input data collection system (manufactured by Keyence Corporation, NR-500, NR-TH08). The temperature and humidity in the small environmental tester were monitored with a temperature / humidity probe (manufactured by Nippon Shintech Co., Ltd., NS-04AP). Temperature 25 ° C. A stable inter-terminal resistance value after being held at a humidity of 90% RH for 30 minutes was defined as an inter-terminal resistance value [A] at 25 ° C. and a humidity of 30% RH.

(3) Resistance measurement method between terminals at 80 ° C. and humidity 30% RH A small environmental tester (SH-221, manufactured by ESBET Co., Ltd.) is put in a state where clips are attached to both electrodes of the conductive laminate with electrodes, Temperature 25 ° C. It was kept at a humidity of 90% RH for 120 hours. The inter-terminal resistance value in the small environmental tester was recorded every 30 seconds using a multi-input data collection system (manufactured by Keyence Corporation, NR-500, NR-TH08). The temperature and humidity in the small environmental tester are 80 ° C, the stable resistance between terminals after holding for 120 hours at a temperature of 80 ° C and humidity of 30% RH monitored by a temperature and humidity probe (Nippon Shintech, NS-04AP). The inter-terminal resistance value [B] was 30% humidity.

[Substrate production example]
Ni (10 nm) and Au (100 nm) were sequentially deposited on a glass substrate (15 mm × 15 mm × 1 mm) using a metal mask. An electron beam deposition method was used for Ni deposition, and a low resistance heating deposition method was used for Au deposition.

[CNT conductive layer formation example 1]
Two-layer CNT (Toray Industries, Inc., diameter 1.7 nm) was used. The two-layer CNT ratio determined according to the method for measuring the number of CNT layers was 90%. Ultrasonic dispersion treatment was performed using a dispersant in water. The dispersion was applied to a glass substrate with a gold electrode by subbing to obtain a CNT conductive layer.

[CNT formation layer formation example 2]
Single-walled CNT synthesized by an arc discharge method (manufactured by Meijo Nano Carpon Co., Ltd., SWCNT SO, diameter˜1.4 nm) was used. The single-wall CNT ratio determined according to the method for measuring the number of CNT layers was 70%. Single-walled CNT synthesized by the arc discharge method was subjected to super-wave dispersion in ethanol, and the dispersion was applied to a glass substrate with a gold electrode by spraying to obtain a CNT conductive layer.

[Example of a 2-coordinate boron cation salt synthesis method]
Et ₃ Si ⁺ [(C ₆ F ₅ ) ₄ B] ^one mesitylene adduct (see FIG. 1) in a glove box in which oxygen concentration and water concentration are controlled to 0.1 ppm or less in an argon or nitrogen atmosphere, respectively. ) (59.0 mg, 9.26 × 10 ⁻² mmol) in a dry orthodichlorobenzene solution (1.0 mL) was added fluorodimesitylborane (24.8 mg, 9.26 × 10 ⁻² mmol) at room temperature, The mixture was stirred at 25 ° C. for 5 minutes. The reaction solution was distilled off under reduced pressure and concentrated to about 0.5 mL. A colorless transparent crystal was precipitated by introducing hexane vapor into the obtained reaction mixture by vapor diffusion. The crystals are collected by filtration and washed with dry hexane to give a dimesitylborinium ion (Mes ₂ B ⁺ [(C ₆ F ₅ ) ₄ B) having tetrakis (pentafluorophenyl) porate as a counter anion. ] ^- ) (See FIG. 2) was obtained as colorless transparent crystals in a yield of 92%.

[Two-coordinate boron cation salt distribution]
Ortho-sitalobenzene saturated solution of (Mes ₂ B ⁺ [(C ₆ F ₅ ) ₄ B] ⁻ ) described in the example of the synthesis method of a two-coordinate boron cation salt in a glove box (oxygen and water of 1 ppm or less) in a room atmosphere. Was immersed in the CNT conductive layer for 1 minute, and then heated on a heater (60 ° C.) for 10 to 15 minutes.

(Example 1) DWCNT / 2-coordinated boron cation salt The conductive layer formed in accordance with CNT conductive layer formation example 1 was treated in accordance with a 2-coordinated boron cation salt coating (dimethylpolynium ion). Thereafter, the resistance value [A] between terminals at 25 ° C. and a humidity of 30% RH and the resistance value [B] between terminals at a temperature of 80 ° C. and a humidity of 30% RH were measured. The measurement results are shown in Table 1 below.

(Example 2) SWCNT / 2-coordinated boron cation salt The conductive layer formed according to CNT conductive layer formation example 2 was treated according to the application of 2-coordinated boron cation salt (dimethylborinium ion). Thereafter, the resistance value [A] between terminals at 25 ° C. and a humidity of 30% RH and the resistance value [B] between terminals at a temperature of 80 ° C. and a humidity of 30% RH were measured. The measurement results are shown in Table 1 below.

(Comparative Example 1) DWCNT
Measurement of resistance value [A] between terminals at 25 ° C. and humidity 30% RH and resistance value [B] between terminals at 80 ° C. and humidity 30% RH for the conductive layer formed according to CNT conductive layer formation example 1. did. The measurement results are shown in Table 1 below.

(Comparative example 2) DWCNT / nitric acid Concentrated nitric acid was applied by spin coating to the conductive layer formed in accordance with formation example 1 of the CNT conductive layer, and the low resistance value [A] between terminals at 25 ° C and 30% RH was applied. The resistance value [B] between terminals at 80 ° C. and a humidity of 30% RH was measured. The measurement results are shown in Table 1 below.

(Comparative Example 3) SWCNT
Measurement of resistance value [A] between terminals at 25 ° C. and humidity 30% RH and resistance value [B] between terminals at 80 ° C. and humidity 30% RH for the conductive layer formed according to CNT conductive layer formation example 2. did. The measurement results are shown in Table 1 below.

As shown in Table 1, the inter-terminal resistance value [B] of Example 1 at 80 ° C. and a humidity of 30% RH is smaller than the inter-terminal resistance value [B] of Comparative Example 1 at 80 ° C. and a humidity of 30% RH. The resistance value change rate [B] / [A] of Example 1 is smaller than the resistance value change rate [B] / [A] of Comparative Examples 1 and 2. Furthermore, the resistance value [B] between terminals at 80 ° C. and a humidity of 30% RH in Example 2 is smaller than the resistance value [B] between terminals at 80 ° C. and a humidity of 30% RH in Comparative Example 3, and the resistance of Example 2 The value change rate [B] / [A] is smaller than the low resistance value change rate [B] / [A] of Comparative Example 3. It was confirmed that the single-layer and / or double-walled CNT-containing compositions according to the examples were excellent in conductivity and resistance value stability under a high temperature environment.

The multilayer CNT-containing composition according to the present invention is suitable for a wide range of applications such as electrode materials, semiconductor layers such as thin film transistor substrates, sensors, actuators, building materials, paints, CNT paper, and medical equipment. In addition, the single-layer and / or double-layer CNT-containing composition is suitable for use in electronic materials including electrode materials.

This application claims priority based on Japanese Patent Application Nos. 2016-026051 and 2016-026000 filed on Feb. 15, 2016, the entire disclosure of which is incorporated herein.

Claims (10)

1. A method for producing a multi-walled carbon nanotube-containing composition comprising:
   Including a contacting step in which a multi-walled carbon nanotube containing 35% or more of three or more layers of carbon nanotubes is brought into contact with a two-coordinate boron cation salt when the total number of carbon nanotubes is 100%.
   A method for producing a multi-walled carbon nanotube-containing composition.
2. The bicoordinate boron cation of the bicoordinate boron cation salt is represented by the following general formula (1):
   

   

   [Wherein R ¹ and R ² are each independently a phenyl group, a mesityl group, a 1,5-dimethylphenyl group, a 1,3,5-triisopropylphenyl group, a 1,5-diisopropylphenyl group, 1, It is a compound selected from the group consisting of 3,5-tris (trifluoromethyl) phenyl group and 1,5-bis (trifluoromethyl) phenyl group. ]
   The manufacturing method of the multilayer carbon nanotube containing composition of Claim 1 represented by these.
3. The counter-anion of the bicoordinate boron cation salt includes at least one of a fluorine-based anion and a carborane derivative;
   The fluorine-based anion is at least one selected from the group consisting of BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenyl borate, tetrakis (pentafluorophenyl) borate,
   The carborane derivative is at least one selected from the group consisting of monocarbacrode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and monocarbacroso undecachlorododecaborate (HCB ₁₁ Cl ₁₁ ⁻ ). Item 3. A method for producing a multi-walled carbon nanotube-containing composition according to Item 1 or 2.
4. The contact step includes
   (I) coating the carbon nanotube on a substrate, and contacting the obtained coating film and the two-coordinate boron cation salt;
   (Ii) mixing the carbon nanotubes and the two-coordinate boron cation salt in a solvent;
   The multi-walled carbon nanotube-containing composition according to any one of claims 1 to 3, comprising at least one selected from the step of (iii) mixing the carbon nanotube powder and the two-coordinate boron cation salt powder. Manufacturing method.
5. When the total number of carbon nanotubes is 100%, multi-walled carbon nanotubes containing 35% or more of three or more layers of carbon nanotubes,
   A counter-anion of a two-coordinate boron cation salt,
   The counter anion is
   Including at least one of a fluorine-based anion and a carborane derivative,
   The fluorine _{^{anion, BF 4 -, PF 6 -}} TFSI, tetraphenylborate, at least one selected from the group consisting of tetrakis (pentafluorophenyl) borate,
   The carborane derivative is at least one selected from the group consisting of monocarburcrode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and monocarburco undecachlorododecaborate (HCB ₁₁ Cl ₁₁ ⁻ ). Carbon nanotube-containing composition.
6. The multi-walled carbon nanotube-containing composition according to claim 5, further comprising a resin.
7. A method for producing a single-walled and / or double-walled carbon nanotube-containing composition comprising:
   When the total number of carbon nanotubes is 100%, single-walled carbon nanotubes and / or double-walled carbon nanotubes containing 70% or more of single-walled carbon nanotubes and / or double-walled carbon nanotubes are brought into contact with the bicoordinate boron cation salt. Including the contacting step,
   A method for producing a single-walled and / or double-walled carbon nanotube-containing composition.
8. The bicoordinate boron cation of the bicoordinate boron cation salt is represented by the following general formula (1):
   

   

   [Wherein R ¹ and R ² are each independently a phenyl group, a mesityl group, a 1,5-dimethylphenyl group, a 1,3,5-triisopropylphenyl group, a 1,5-diisopropylphenyl group, 1, It is a compound selected from the group consisting of 3,5-tris (trifluoromethyl) phenyl group and 1,5-bis (trifluoromethyl) phenyl group. ]
   The manufacturing method of the single-layer and / or double-walled carbon nanotube containing composition of Claim 7 represented by these.
9. The counter-anion of the bicoordinate boron cation salt includes at least one of a fluorine-based anion and a carborane derivative;
   The fluorine-based anion is at least one selected from the group consisting of BF ₄ ⁻ , PF ₆ ⁻ , TFSI, tetraphenyl borate, tetrakis (pentafluorophenyl) borate,
   The carborane derivative is at least one selected from the group consisting of monocarbacrode decaborate (HCB ₁₁ H ₁₁ ⁻ ) and monocarbacroso undecachlorododecaborate (HCB ₁₁ Cl ₁₁ ⁻ ). Item 9. The method for producing a single-walled and / or double-walled carbon nanotube-containing composition according to Item 7 or 8.
10. The contact step includes
    (I) applying the said single-layer and / or double-walled carbon nanotube containing material on a base material, and apply | coating the said 2 coordination boron cation salt on the obtained coating film. A method for producing the single-walled and / or double-walled carbon nanotube-containing composition according to any one of 1 to 9.

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