JP2021183557A - Boron-containing carbon material, conductive composition, and conductive film - Google Patents

Abstract

To provide a boron-containing carbon material excellent in conductivity, and to provide an excellent conductive material containing the boron-containing carbon material.SOLUTION: A boron-containing carbon material is doped so that boron elements replace at least some of carbon elements in a carbon skeleton, and when the Raman shift of a G band is X and the Raman shift of a D band is Y in a laser Raman spectrum, the difference [X-Y] of the Raman shifts is 226 cm-1 or less, and the ratio of surface substitution type boron elements to all elements on a surface of the boron-containing carbon material, as measured by X-ray photoelectron spectroscopy (XPS), is 0.0001 or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to boron-containing carbon materials, conductive compositions, and conductive films.

In recent years, the development of electronics has been remarkable, and conductive materials used in various electronic devices are required to be smaller and lighter, cost lower, and have a longer life in various usage environments. It's coming. For example, when manufacturing a board wiring for an electronic device or a wiring for connecting an electronic device, a conductive composition having good conductivity is required, but a conductive composition using a metal filler such as silver or copper is generally used. However, major problems in terms of cost and durability have not yet been solved. On the other hand, various studies have been conducted on conductive compositions using a conductive carbon material that does not use metal, but since the conductivity is insufficient, it is limited to use in semi-conductive applications such as antistatic applications. Has been done.

As a conductive carbon material, highly conductive carbon such as graphite and carbon nanotubes has also been studied. It has been reported that the volume resistivity of these highly conductive carbons has ^{excellent conductivity of less than 10-2} Ω · cm, and that the problem of conductivity can be improved as compared with the conventional ones (Patent Documents 1 and 2). ). However, the volume resistivity of the material itself is orders of magnitude higher than that of the metal filler, and it cannot be said that conductive carbon alone can exhibit sufficient characteristics for conductive applications.

On the other hand, research on carbon materials with high crystallinity is being conducted for the purpose of solving the problem of conductivity of carbon materials themselves. For example, regarding the method for producing carbon nanotubes, the flow velocity and concentration of the raw material gas may be improved to improve the crystallinity (Patent Document 3), or the graphene on the surface of carbon fibers may be bonded to each other by the catalytic action of liquid Ga. (Patent Document 4) has been reported. However, it cannot be said that the improvement of conductivity is sufficient, and further development of a highly conductive carbon material is required.

Japanese Unexamined Patent Publication No. 3-7740 Japanese Unexamined Patent Publication No. 2008-293821 Japanese Unexamined Patent Publication No. 2010-006663 Japanese Unexamined Patent Publication No. 2009-179915

In view of the above problems, it is an object of the present invention to provide an excellent conductive material by realizing a boron-containing carbon material having excellent conductivity.

The present inventor has arrived at the present invention as a result of repeated diligent studies to solve the above-mentioned problems.
That is, the present invention is a boron-containing carbon material in which a boron element is doped so as to replace at least a part of the carbon element in the carbon skeleton, and the Raman shift of the G band in the laser Raman spectrum is X and the D band. When the Raman shift is Y, the difference in Raman shift [XY] is 226 cm ^-1 or less, and the surface substitution type for all elements on the surface of the boron-containing carbon material as measured by X-ray photoelectron spectroscopy (XPS). The present invention relates to a boron-containing carbon material having a boron element ratio of 0.0001 or more.

The present invention also relates to the above-mentioned boron-containing carbon material containing at least one selected from the group consisting of a graphite-based carbon material, a graphene-based carbon material, and a carbon nanotube-based carbon material.

The present invention also relates to the above-mentioned boron-containing carbon material having an intensity ratio [G / D] of G band to D band in the laser Raman spectrum of 6 or less.

The present invention also relates to the above-mentioned boron-containing carbon material having a Raman shift difference [XY] of 218 to 226 cm ^-1.

The present invention also relates to a conductive composition containing the above-mentioned boron-containing carbon material and at least one of a binder resin or a solvent.

The present invention also relates to the above conductive composition further containing a conductive auxiliary agent.

The present invention also relates to the above-mentioned conductive composition having a specific surface area of a conductive auxiliary agent of 150 to 550 m ^{2 / g.}

The present invention also relates to a conductive film formed from the above conductive composition.

According to the present invention, it is possible to provide a boron-containing carbon material having excellent conductivity.

FIG. 1 is a diagram showing peaks of G band and D band of a boron-containing carbon material in a laser Raman spectrum. FIG. 2 is a diagram showing an example of peak separation of the B1s spectrum in XPS.

Hereinafter, the present invention will be described in detail. In the present specification, the "boron-containing carbon material" may be simply referred to as a carbon material.

<Boron-containing carbon material>
The boron-containing carbon material in which the boron element is doped so as to replace at least a part of the carbon element in the carbon skeleton is a carbon hexagonal network surface in which carbon atoms are covalently bonded in a hexagonal network. It consists of carbon materials that have physical and chemical interactions (bonds) between their constituent units, and are doped so that at least elemental boron replaces part of the elemental carbon, and in some cases nitrogen. It is a carbon material containing heterogeneous elements such as elements and phosphorus elements, and base metal elements.

^{The boron-containing carbon material has Raman when the Raman shift of the G band (1560-1620 cm -1} ) in the laser Raman spectrum with an excitation laser wavelength of 532 nm is X and the Raman shift of the D band (1330-1370 cm ^-1 ) is Y. When the shift difference [XY] is 226 cm ^-1 or less, it tends to lead to an increase in carriers due to boron doping. Preferably 218cm ^-1 or 226 cm ^-1 or less, and more preferably 222cm ^-1 or 226 cm ^-1 or less.

The conductivity of the boron-containing carbon material is expressed by the following formula.
σ = μ × n × e (Equation 1) μ: mobility, n: carrier density, e: elementary charge (constant)
In order to improve the conductivity from the above (Equation 1), it is necessary to improve the mobility and / or the carrier density. The main aim of boron doping in carbon materials is to improve the carrier density by introducing holes by element substitution in the carbon skeleton. On the other hand, the boron dope to the carbon material has a great influence on the crystal structure and electronic state of carbon, and induces disorder of the crystal structure of carbon and deterioration of crystallites, which is also a factor of lowering the mobility.

When the carbon material is doped with carriers by boron, the change in the Fermi level of the carbon material causes a change in the electron-lattice interaction, causing a high wave shift of the D-band and G-band peaks in the Raman spectrum. .. On the other hand, a decrease in the number of layers of the hexagonal network surface of carbon also causes a high wave number shift at the peak of the G band. From these, by keeping the difference in Raman shift [XY] within the range of the present invention, the carrier density is increased by doping with boron, and the mobility due to the decrease in the number of stacked hexagonal net surfaces (decrease in crystallinity). It is considered that high conductivity can be exhibited by suppressing the decrease in the value.

Boron-containing carbon material, G / D ratio is the ratio of the peak intensity (IG / ID) of D-band (1330~1370cm ^-1) and G bands in the laser Raman spectrum of the excitation laser wavelength 532nm (1560~1620cm ^-1) When is 0.5 or more and 20 or less, there are few defects on the carbon surface and crystal interfaces, and electron conduction tends to be high, which is preferable. It is more preferably 1 or more and 10 or less, still more preferably 1 or more and 6 or less, still more preferably 1 or more and 5 or less, and particularly preferably 2 or more and 5 or less. In particular, when the G / D ratio is 6 or less, it is easy to improve the carrier density and maintain the crystallinity by doping with boron, so that the electron conduction tends to be high. ,

The form of the boron element on the surface of the boron-containing carbon material is not particularly limited, but is a substituted boron element (BC ₃ type) in which the boron element is substituted at the position of the carbon element in the carbon skeleton, a boron carbide type and a boron cluster type. boron element _{(B 4} C type, Bc type), completely or partially oxidized boron type elemental boron oxidized state (BC ₂ O type, BCO _{2 type,} B 2 _{O 3} type) and the like.

In the boron-containing carbon material, the ratio of the surface-substituted boron element to all the elements on the surface of the boron-containing carbon material measured by X-ray photoelectron spectroscopy (XPS) is 0.0001 or more, and the carrier density due to the boron element dope is determined. It has the effect of improving. The ratio of the surface-substituted boron element is the ratio B of the spectral area of the total boron element to the spectral area of all the elements on the surface of the carbon material measured by XPS, and the ratio of the total boron element on the surface of the carbon material obtained from the B1s spectrum of XPS. when the ratio of the peak area of substitutional boron element to the spectral area was B _R, represented by B × B _R. It is more preferably 0.0002 or more, still more preferably 0.0004 or more. The ratio of the surface-substituted boron element is preferably 0.01 or less, more preferably 0.005 or less.

When the boron-containing carbon material contains boron, the wettability with respect to the solvent and the binder resin is enhanced, and the dispersibility of the dispersion liquid is improved. Further, when the boron content is high, the hardness of the carbon material tends to increase. As a result, the durability against an external force such as an impact is improved, so that the dispersion stability and the film strength are improved. On the other hand, if the boron content is high, dispersion tends to be difficult. Therefore, from the viewpoint of the strength and dispersibility of the carbon material, the ratio of the surface-substituted boron element is preferably 0.0002 or more and 0.01 or less. , More preferably 0.0004 or more and 0.005 or less.

It is known that the B1s spectrum of boron obtained by XPS measurement appears in the binding energy range (around 185 to 197 eV) of the B1s electron of the boron element, and is roughly classified into four components. The value of the binding energy (peak top) of each component is 186 to 187 eV for boron clusters, 187 to 188 eV for boron carbide, and boron (BC _{3) doped so as to replace carbon elements having a hexagonal network as the basic skeleton.} ) Appears in 188 to 189.3 eV, BC ₂ O which is various boron oxides appears in 189.5 to 190.5 eV, BCO ₂ appears in 191.5 to 192 eV, and B ₂ O ₃ appears in 192.5 to 193 eV. When these peaks overlap, the ratio can be obtained by performing fitting and separating the peaks by optimizing each component as a Gaussian function with the peak intensity, peak position, and full width at half maximum as parameters. can. Therefore, it is possible to perform peak separation of B1s and analyze the state of boron on the surface of the boron-doped carbon material.

The boron-containing carbon material is not particularly limited, and examples thereof include a graphite-based carbon material, a carbon nanotube-based carbon material, a graphene-based carbon material, and a carbon black-based carbon material. Graphite-based carbon materials, carbon nanotube-based carbon materials, and graphene-based carbon materials are preferable because the crystallinity of the boron-containing carbon material tends to be high, such as the G / D ratio.

The particles of the boron-containing carbon material in the present invention have high crystallinity, and a larger particle is preferable because it is advantageous for electron conductivity. The thickness of the particles is preferably larger than 50 nm. More preferably, it is larger than 100 nm. More preferably, it is 250 nm or more. The thickness of the particles of the boron-containing carbon material can be calculated from the average value of the thicknesses of the particles randomly sampled by, for example, an electron microscope.

<Manufacturing method>
The method for producing the boron-containing carbon material of the present invention is not particularly limited, but a method including a step of mixing a carbon-based raw material and a compound containing boron and a step of heat-treating the mixture at a high temperature of 1000 ° C. or higher is preferable. ..
The method for producing the boron-containing carbon material of the present invention is preferably a method of doping a pre-carbonized carbon source with boron. The term "carbonization" as used herein represents an event similar to "crystallization" or "graphitization".
For example, in the method of obtaining a boron-containing carbon material by doping boron while carbonizing using an uncarbonized carbon source and a boron source, or in a method using a carbon source which has been subjected to a preliminary firing treatment in advance, crystallization or Graphitization may be inadequate. For this reason, it is better to use a method of performing a boron doping reaction after carbonization, such as doping a pre-carbonized carbon source with boron, rather than a method of doping boron while carbonizing, on the surface and inside of carbon particles. It is preferable because a carbon material having a preferable distribution state of boron can be produced. That is, in order to obtain the boron-containing carbon material of the present invention capable of achieving both excellent oxidation resistance, conductivity, dispersibility, and durability, selection of a carbon source and carbon when a boron doping reaction occurs are performed. The mixed state of the source and the boron source is also important.

The raw material composition ratio of the carbon-based raw material for producing the boron-containing carbon material and the raw material composition ratio of the compound containing boron is not particularly limited, but the ratio of the compound containing boron to 100 parts by mass of the carbon-based raw material is preferable. It is 0.01 to 300 parts by mass, more preferably 0.1 to 100 parts by mass.

The method for producing the mixture may contain at least a carbon-based raw material and a compound containing boron, and examples of the mixing method include dry mixing and wet mixing. As the mixing device, the following dry mixing device and wet mixing device can be used as the mixing device.

Dry mixers include, for example, roll mills such as 2-roll and 3-roll, high-speed stirrers such as Henshell mixers and super mixers, fluid energy crushers such as micronizers and jet mills, attritors, and particle composites manufactured by Hosokawa Micron. Devices such as "Nanocure", "Novirta", "Mechanofusion", powder surface reformer "Hybridation System" manufactured by Nara Machinery Works, "Mechanomicros", "Miraro" and the like can be mentioned.

Further, when using a dry mixing device, two or more kinds of raw materials may be directly mixed as powders, but in order to prepare a more uniform mixture, one or more kinds of raw materials are previously dissolved in a small amount of solvent. Alternatively, a method of dispersing and mixing may be used. In order to further increase the processing efficiency, heating may be performed.

Wet mixing devices include, for example, mixers such as a disper, homomixer, or planetary mixer, homogenizers such as "Clairemix" manufactured by M-Technique, or "Fillmix" manufactured by PRIMIX, and paint manufactured by Red Devil. Conditioner, ball mill, sand mills such as "Dyno Mill" manufactured by Symmal Enterprises, media type disperser such as Attritor or Coball Mill, "Genus PY" manufactured by Genus, "Star Burst" manufactured by Sugino Machine, manufactured by Nanomizer. Wet jet mills such as "Nanmizer", medialess dispersers such as "Claire SS-5" manufactured by M-Technique, or "Micros" manufactured by Nara Machinery Co., Ltd., or other roll mills, kneaders, etc. may be mentioned. However, it is not limited to these. Further, as the wet mixing device, it may be preferable to use a device that has been subjected to a metal contamination prevention treatment from the device.

For example, when using a media-type disperser, a method in which the agitator and vessel use a disperser made of ceramic or resin, or a disperser in which the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. It is preferable to use. As the medium, it is preferable to use glass beads, zirconia beads, or ceramic beads such as alumina beads. Also, when using a roll mill, it is preferable to use a ceramic roll. As the dispersive device, only one type may be used, or a plurality of types of devices may be used in combination.

Further, when the raw materials are not uniformly dissolved, a general dispersant may be added together, dispersed and mixed in order to improve the wettability and dispersibility of each raw material in the solvent.

As the dispersant, the dispersant used in the present invention effectively functions as a dispersant for each raw material and can alleviate the aggregation thereof. There is no particular limitation as long as it has the effect of alleviating aggregation, and conventionally known ones can be used. For example, dispersants such as resin-type dispersants, surfactants, and pigment derivatives can be used.

Examples of the resin-type dispersant include polyvinyl-based resins, polyurethane-based, polyester-based, polyether-based, cellulose resins such as carboxymethyl cellulose, formalin condensates, silicon-based polymers, and composite polymers thereof. Further, two or more kinds of these resin type dispersants may be used in combination. Polyvinylpyrrolidone, polyvinyl alcohol, polystyrene sulfonic acid, polyacrylic acid, carboxymethyl cellulose and the like are preferable.

In the method for heat-treating the mixture, the heating temperature is preferably 1000 to 3200 ° C, more preferably 1800 to 3000 ° C, although it varies depending on the type and amount of the carbon-based raw material as a raw material and the compound containing boron.

The heating time is not particularly limited, but is usually preferably 30 minutes to 10 hours.

Regarding the atmosphere in the heat treatment step, an inert gas atmosphere such as nitrogen or argon or a vacuum atmosphere is preferable in order to prevent oxidation of the raw material.

Further, regarding the heat treatment step, not only the method of performing the treatment in one step under a constant atmosphere and temperature, but also the heat treatment step may be performed in multiple steps by changing the atmosphere and temperature each time.

<Carbon-based raw material>
As the carbon-based raw material for producing the boron-containing carbon material in the present invention, an inorganic carbon-based raw material is preferable. Specific examples of inorganic carbon-based raw materials include carbon black (furness black, acetylene black, ketjen black, medium thermal carbon black), activated carbon, graphite, carbon nanotubes, carbon nanofibers, carbon nanohorns, graphene, and graphene nanoplatelets. Examples include nanoporous carbon, carbon fiber, and charcoal. Among the above carbon-based raw materials, the size and laminated structure of the carbon hexagonal network vary depending on the type and manufacturer, and the crystallinity, particle size, shape, BET specific surface area, pore volume, pore diameter, bulk density, and DBP oil absorption amount. Since various physical properties such as surface acid basicity, surface hydrophilicity, and conductivity and costs are different, the optimum material can be selected according to the intended use and required performance.

As commercially available carbon-based raw materials, for example, as commercially available graphite, CMX, UP-5, UP-10, UP-20, UP-35N, CSSP, CSPE, CSP, CP, CB- manufactured by Nippon Graphite Industry Co., Ltd. 150, CB-100, ACP, ACP-100, ACB-50, ACB-100, ACB-150, SP-10, SP-20, J-SP, SP-270, HOP, GR-60, LEP, F # 1, F # 2, F # 3, CGC-20, CGC-50, CGB-20, CGB-50, PAG-60, PAG-80, PAG-120, PAG-5, HAG-10W, HAG-150, etc. , EC1500, EC1000, EC500, EC300, EC100, EC50, etc. manufactured by Ito Graphite Industry Co., Ltd., CX-3000, FBF, BF, CBR, SSC-3000, SSC-600, SSC-3, SSC, CX manufactured by Chuetsu Graphite Co., Ltd. -600, CPF-8, CPF-3, CPB-6S, CPB, 96E, 96L, 96L-3, 90L-3, CPC, S-87, K-3, CF-80, CF-48, CF-32 , CP-150, CP-100, CP, HF-80, HF-48, HF-32, SC-120, SC-80, SC-60, SC-32, RA-3000, RA-15, RA-44 , GX-600, G-6S, G-3, G-150, G-100, G-48, G-30, G-50, SGP-100, SGP-50, SGP-25, manufactured by SEC Carbon Co., Ltd. SGP-15, SGP-5, SGP-1, SGO-100, SGO-50, SGO-25, SGO-15, SGO-5, SGO-1, SGX-100, SGX-50, SGX-25, SGX- 15, SGX-5, SGX-1, etc., 10099M, PB-99, etc. manufactured by Nishimura Graphite Co., Ltd. can be mentioned.
Commercially available carbon blacks include Ketjen Black EC-300J, EC-600JD, Lionite EC-200L, etc. manufactured by Lion Specialty Chemicals.
Examples include Furness Black # 2350, # 2600, # 3050B, # 3030B, # 3230B, # 3400B, etc. manufactured by Mitsubishi Chemical Corporation, and Denka Black HS-100, FX-35, etc. manufactured by Denka Corporation.
Examples of commercially available carbon nanotubes include VGCF-H and VGCF-X manufactured by Showa Denko KK.
Examples thereof include carbon nanotubes manufactured by Meijo Nanocarbon, NTP3003, NTP3021, NTP3121, NTP8012, NTP8022, NTP9012, NTP9112, etc., and TUBALL manufactured by OCSiAl.
Commercially available graphene-based carbons include graphene nanoplatelets xGnP-C-300, xGnP-C-500, xGnP-C-750, xGnP-M-5, xGnP-M-15, xGnP-M-25 manufactured by XGSciences. , XGnP-H-5, xGnP-H-15, xGnP-H-25 and the like, but are not limited thereto.
Among them, graphite is preferable as a commercially available carbon-based raw material from the viewpoint of conductivity and cost.

As the carbon-based raw material for producing the boron-containing carbon material in the present invention, not only the inorganic carbon-based raw material but also the organic carbon-based raw material which is an organic material which becomes carbon particles after heat treatment can be used. Specific organic materials include phenol-based resin, polyimide-based resin, polyamide-based resin, polyamideimide-based resin, polyacrylonitrile-based resin, polyaniline-based resin, phenolformaldehyde resin-based resin, polyimidazole-based resin, polypyrrole-based resin, and poly. Examples thereof include benzoimidazole-based resins, melamine-based resins, pitch, coke, brown charcoal, polycarbodiimide, biomass, proteins, fumic acid and the like, and derivatives thereof. Of these, it is preferable to use coke or pitch, which is also used as a raw material for graphite.

<Compounds containing boron>
Next, a boron-containing compound used for producing a boron-containing carbon material will be described. The compound containing boron is not particularly limited, and examples thereof include boron carbide, boron oxide, boron nitride, metal boride, boronoxoic acid, borane, and a boron-containing organic compound.
Specifically, for boron carbide, B ₄ C (B ₁₂ C ₃ ), B ₁₂ C ₂ (B ₆ C), etc.
For boron oxide, BC ₂ O, BCO ₂ , B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₃ , B ₄ O _5, etc.
For boron nitride, BN, etc.
For metal borides, AlB ₂ , CoB, FeB, MgB ₂ , NiB, TiB _2, etc.
For boron oxo acid, orthoboric acid, metaboric acid, tetraboric acid, etc.
In Borane, Monoborane, Diborane, Decaborane, etc.
Examples of the boron-containing organic compound include borate esters such as trimethyl borate and triethyl borate, substituted boranes such as triethylborane and triphenylborane, and borane acids such as phenylboronic acid and phenylboronic acid ester.

<Conductive composition>
The conductive composition of the present invention contains the above-mentioned boron-containing carbon material and at least one of a binder resin or a solvent. The conductive composition may contain two or more different carbon materials in combination, or may contain a conductive auxiliary agent if necessary.

<Binder resin>
The binder resin is not particularly limited, and is not particularly limited, for example, polyurethane resin, polyamide resin, acrylonitrile resin, acrylic resin, butadiene resin, polyvinyl resin, polyvinyl butyral resin, polyolefin resin, polyester resin, polystyrene. It may contain at least one selected from the group consisting of based resins, EVA resins, polyvinylidene fluoride resins, polytetrafluoroethylene resins, silicone resins, polyether resins, cellulose resins such as carboxymethyl cellulose and the like. can.
The binder resin may be used alone or in combination of two or more.

The binder resin preferably contains at least one selected from the group consisting of polyurethane-based, polyamide-based resin and polyester-based resin from the viewpoint of volume resistance, adhesion to the substrate and durability, and contains polyurethane-based resin. Is more preferable. The binder resin is preferably one that is appropriately softened or flows when the conductive composition is printed or coated on a substrate and then pressed or hot-pressed (hereinafter referred to as (heat) press). By using such a resin, the conductive composition flows in the thickness direction while maintaining the planar pattern shape of the coating film, the voids in the film are reduced, and the contact points between the carbon materials are increased. , A conductive film having a low volume resistivity can be obtained.

[Polyurethane resin]
The method for synthesizing the polyurentane resin is not particularly limited, but for example, a method for reacting the polyol compound (a) with the diisocyanate (b), the polyol compound (a), the diisocyanate (b), and the diol compound (c) having a carboxyl group. In a method of obtaining a urethane prepolymer (d) having an isocyanate group, a method of further reacting the urethane prepolymer (d) with the polyamino compound (e), or the above three methods, if necessary, the reaction is carried out. A method of reacting the terminator may be mentioned.

As the polyol compound (a), various known polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene glycols, or a mixture thereof can be used as the polyol component constituting the polyurethane resin.

Examples of the polyether polyols include polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran and the like.
Examples of the polyester polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1, Saturated and unsaturated low molecular weight diols such as 5-pentanediol, hexanediol, octanediol, 1,4-butylenediol, diethyleneglycol, triethyleneglycol, dipropyleneglycol, dimerdiol, and n-butylglycidyl ether, 2 -Alkyl glycidyl ethers of ethylhexyl glycidyl ethers, monocarboxylic acid glycidyl esters such as versatic acid glycidyl esters, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, Dicarboxylic acids such as malonic acid, glutaric acid, pimelli acid, oxalic acid, azelaic acid, and sebacic acid, or anhydrides thereof are dehydrated and condensed to obtain polyester polyols or cyclic ester compounds by ring-opening polymerization. Examples thereof include the obtained polyester polyols.
As the polycarbonate polyols, (1) a reaction product of diol or bisphenol and carbonic acid ester, and (2) a reaction product of diol or bisphenol with phosgene in the presence of alkali can be used. Examples of the carbonic acid ester include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate and the like. Examples of the diol include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, and 3,3'-. Dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonane Diol, Neopentyl Glycol, Octanediol, Butylethylpentanediol, 2-Ethyl-1,3-Hexanediol, Cyclohexanediol, 3,9-Bis (1,1-dimethyl-2-hydroxyethyl, 2,2,8) , 10-Tetraoxospiro [5.5] undecane and the like. Examples of the bisphenol include bisphenol A and bisphenol F, and bisphenols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to bisphenols. Be done.

The number average molecular weight (Mn) of the polyol compound is appropriately determined in consideration of the solubility of the polyurethane resin in producing the conductive composition, the durability of the conductive film formed, the adhesive strength to the substrate, and the like. However, it is usually preferably in the range of 580 to 8,000, more preferably in the range of 1,000 to 5,000.
The above-mentioned polyol compound may be used alone or in combination of two or more. Further, as long as the performance of the polyurethane resin is not lost, a part of the polyol compound can be replaced with low molecular weight diols, for example, various low molecular weight diols used for producing the polyol compound.

As the diisocyanate compound (b), an aromatic diisocyanate, an aliphatic diisocyanate, an alicyclic diisocyanate, or a mixture thereof can be used. It is preferably an alicyclic diisocyanate, and more preferably an isophorone diisocyanate. Examples of the aromatic diisocyanate include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-benzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and 1, , 3-Phenylene diisocyanate, 1,4-Phenylene diisocyanate, Tolylene diisocyanate, Xylylene diisocyanate and the like.

Examples of the aliphatic diisocyanate include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.
Examples of the alicyclic diisocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, norbornane diisocyanatomethyl, bis (4-isocyanatecyclohexyl) methane, 1,3-bis (isocyanatemethyl) cyclohexane, and methylcyclohexanediisocyanate. Can be mentioned.

Examples of the diol compound (c) having a carboxyl group include dimethylol alkanoic acid such as dimethylol acetic acid, dimethylol propionic acid, dimethylol butanoic acid and dimethylol pentanoic acid, dihydroxysuccinic acid and dihydroxybenzoic acid. In particular, dimethylolpropionic acid and dimethylolbutanoic acid are preferable from the viewpoint of reactivity and solubility.
The condition for reacting the polyol compound (a) with the diisocyanate (b) and the diol compound (c) having a carboxyl group to obtain the urethane prepolymer (d) having an isocyanate group may be an excess of the isocyanate group. , Others are not particularly limited, but the isocyanate group / hydroxyl group equivalent ratio is preferably in the range of 1.05 / 1-3 / 1. More preferably, it is 1.2 / 1 to 2/1. The reaction is usually carried out between room temperature and 150 ° C., and is preferably carried out between 60 and 120 ° C. in terms of production time and control of side reactions.

The polyamino compound (e) acts as a chain extender, for example, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, norbornandiamine and others. , 2- (2-Aminoethylamino) ethanol, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxypropylethylenediamine and other amines with hydroxyl groups are used. be able to. Among them, isophorone diamine is preferably used.

When synthesizing a polyurethane resin by reacting a urethane prepolymer (d) having an isocyanate group with a polyamino compound (e), a reaction terminator can be used in combination for the purpose of adjusting the molecular weight of the obtained polyurethane resin. As the reaction terminator, dialkylamines such as di-n-butylamine, dialkanolamines such as diethanolamine, and alcohols such as ethanol and isopropyl alcohol can be used.

The conditions for reacting the urethane prepolymer (d) having an isocyanate group with the polyamino compound (e) and, if necessary, a reaction terminator are not particularly limited, but the free isocyanate groups at both ends of the urethane prepolymer are not particularly limited. When 1 equivalent is used, the total equivalent of the polyamino compound (e) and the amino group in the reaction terminator is preferably in the range of 0.5 to 1.3. More preferably, it is in the range of 0.8 to 0.995.
The weight average molecular weight of the polyurethane resin is preferably in the range of 5,000 to 200,000 from the viewpoint of coatability and handleability.

[Polyamide resin]
Polyamide resin is a general term for polymers having an amide bond obtained by various reactions such as polycondensation of dibasic acid and diamine, polycondensation of aminocarboxylic acid, or ring-opening polymerization of lactam, and includes various modified polyamides. , It is produced by a partially hydrogenated reaction product, and a polymer in which other monomers are partially copolymerized, or a polymer in which other substances such as various additives are mixed can be used.
The polyamide resin is not particularly limited, but a dimer acid-modified polyamide resin obtained by condensation polymerization of a dibasic acid containing dimer acid as a main component and polyamines is preferable. Dimer acid As the dimer acid for producing the modified polyamide resin, dimer acid obtained by polymerizing natural monobasic unsaturated fatty acids contained in tall oil fatty acid, soybean oil fatty acid, etc. is widely used industrially, but in principle. May be various dicarboxylic acids such as saturated fatty acid, unsaturated fatty acid, alicyclic, or aromatic. Examples of commercially available products of the dimer acid include Hari Dimer 200, 300 (manufactured by Harima Chemicals, Inc.), Versa Dime 228, 216, Empole 1018, 1019, 1061, 1062 (manufactured by Cognis Co., Ltd.) and the like. Further, hydrogenated dimer acid can also be used, and examples of commercially available hydrogenated dimer acid include Prepole 1009 (manufactured by Croda Japan Co., Ltd.) and Empole 1008 (manufactured by Cognis Co., Ltd.).
In addition to the dimer acid, various dicarboxylic acids can be used as the dibasic acid in order to obtain a polyamide resin having appropriate flexibility. Specific examples of the dicarboxylic acid include oxalic acid, malonic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, glutaric acid, adipic acid, bimeric acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid. Acids, phthalic acids, naphthalenedicarboxylic acids, 1,3- or 1,4-cyclohexanedicarboxylic acids, 1,18-octadecanedicarboxylic acids, 1,16-hexadecanedicarboxylic acids and the like are used.

Further, a dibasic acid having a phenolic hydroxyl group can also be used. By using a dibasic acid having a phenolic hydroxyl group, the phenolic hydroxyl group can be introduced into the side chain of the polyamide resin and can be used for the reaction with the curing agent.
Examples of the dibasic acid having a phenolic hydroxyl group include hydroxyisophthalic acid such as 2-hydroxyisophthalic acid, 4-hydroxyisophthalic acid and 5-hydroxyisophthalic acid, 2,5-dihydroxyisophthalic acid and 2,4-dihydroxyisophthalic acid. Dihydroxyisophthalic acid such as 4,6-dihydroxyisophthalic acid, 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid, dihydroxyterephthalic acid such as 2,6-dihydroxyterephthalic acid, 4-hydroxyphthalic acid, 3-hydroxyphthalic acid Examples thereof include hydroxyphthalic acid such as acid, dihydroxyphthalic acid such as 3,4-dihydroxyphthalic acid, 3,5-dihydroxyphthalic acid, 4,5-dihydroxyphthalic acid and 3,6-dihydroxyphthalic acid.
Further, these acid anhydrides and ester derivatives such as polybasic acid methyl esters can also be mentioned.
Of these, 5-hydroxyisophthalic acid is preferable from the viewpoint of copolymerizability and easy availability.

Further, various monocarboxylic acids are used as needed in order to obtain a polyamide resin having appropriate fluidity when heated. Specifically, as the monocarboxylic acid, propionic acid, acetic acid, caprylic acid (octanoic acid), stearic acid, oleic acid and the like are used.
The polyamines as a reaction product in producing the dimer acid-modified polyamide resin are, for example, various diamines such as aliphatic, alicyclic and aromatic, triamine and polyamine.
Specific examples of the above diamines include ethylenediamine, propanediamine, butanediamine, triethylenediamine, tetraethylenediamine, hexamethylenediamine, p- or m-xylene diamine, 4,4'-methylenebis (cyclohexylamine), and 2,2-bis. -(4-Cyclohexylamine), polyglycoldiamine, isophoronediamine, 1,2-, 1,3- or 1,4-cyclohexanediamine, 1,4-bis- (2'-aminoethyl) benzene, N-ethyl Amino piperazine, piperazine and the like can be mentioned.
Further, examples of the triamine include diethylenetriamine, and examples of the polyamine include triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Further, a dimer diamine obtained by converting a dimerized aliphatic nitrile group and reducing it with hydrogen can also be used.

Examples of the polyamine compound include a compound obtained by converting a carbosyl group of a polybasic acid compound having a cyclic or acyclic hydrocarbon group having 20 to 48 carbon atoms into an amino group, and examples of commercially available products include croaders. Examples thereof include "Priamine 1071", "Priamine 1073", "Priamine 1074" and "Priamine 1075" manufactured by Japan Co., Ltd. and "Versamine 551" manufactured by Cognis Japan Co., Ltd.
Alkanolamine may be used in combination with the diamine. Examples of alkanolamines include ethanolamine, propanolamine, diethanolamine, butanolamine, 2-amino-2-methyl-1-propanol, 2- (2-aminoethoxy) ethanol and the like. Further, a polyether diamine having oxygen in its skeleton can be used. This polyether has the general formula H ₂ N-R ^1- (RO) _n- R ^2- NH ₂ (in the formula, n is 2 to 100, and R ¹ and R ² have 1 to 14 carbon atoms. It is an alkyl group or an alicyclic hydrocarbon group, and R is an alkyl group or an alicyclic hydrocarbon group having 1 to 10 carbon atoms. The alkyl group may be linear or branched. It may be expressed by). Examples of this ether diamine include polyoxypropylene diamine and the like, and commercial products include Jeffamines (manufactured by San Techno Chemical Co., Ltd.). Further, bis- (3-aminopropyl) -polytetrahydrofuran can also be mentioned.
The polyamines and dimer acid or various dicarboxylic acids are heat-condensed by a conventional method, and various polyamide resins including dimer acid-modified polyamide resin are produced by an amidation step accompanied by dehydration. Generally, the reaction temperature is about 100 to 300 ° C., and the reaction time is about 1 to 8 hours.

[Polyester resin]
The polyester resin is a polymer composed of a polyvalent carboxylic acid and a polyhydric alcohol as a monomer. As the polyester resin, known ones can be adopted, and specifically, from the viewpoint of ensuring the cohesive force of the resin, the weight average molecular weight is preferably 1,000 to 100,000. Further, from the viewpoint of adhesion, the glass transition temperature is preferably −10 ° C. to 200 ° C.
Examples of the polyvalent carboxylic acid component include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, unsaturated dicarboxylic acids, trivalent or higher carboxylic acids, and one or more of these are selected and used. can. On the other hand, examples of the polyhydric alcohol component include aliphatic glycols, ether glycols, and trihydric or higher polyalcohols, and one or more of these can be selected and used.
Commercially available polyester resins include Byron (manufactured by Toyobo Co., Ltd., "Byron" is a registered trademark), Polyester (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., "Polyester" is a registered trademark), and Tesslac (manufactured by Hitachi Chemical Polymer Co., Ltd.). , "Teslac" is a registered trademark).

The binder resin is a group consisting of polyether, polyester, polycarbonate and polybutadiene having a functional group capable of reacting with an isocyanate group from the viewpoints of fluidity at the time of heating, volume resistance, adhesion to a substrate and durability. It is also preferable to include a vinyl-based polymer having at least one of the above-selected structures in the side chain. The method for introducing the side chain is not particularly limited, and it can be obtained by various synthetic methods.

Examples of the functional group capable of reacting with the isocyanate group include a hydroxyl group, an amino group, a carboxyl group, an epoxy group, an N-methylol group, an N-alkoxymethyl group and the like, and a hydroxyl group is preferable in terms of reactivity.
The functional group capable of reacting with the isocyanate group can be introduced into the side chain or the main chain of the vinyl polymer, and the introduction method is not particularly limited and can be introduced by various synthetic methods. When used in applications that require high toughness and durability, it is desirable to introduce a functional group capable of reacting with isocyanate directly into the main chain of the vinyl-based polymer, which can improve the crosslink density of the resin. ..

The polystyrene-equivalent weight average molecular weight of the vinyl polymer is preferably 5,000 to 500,000, more preferably 10,000 to 100,000. When the weight average molecular weight is 500,000 or less, the solubility in a solvent is improved, and when it is 5,000 or more, sufficient coating film strength is obtained after (heat) pressing.

As the binder resin, a curable resin that undergoes a curing (crosslinking) reaction after the binder resin is applied to the substrate can also be used.
The cross-linking agent used for the curable resin is not particularly limited, and examples thereof include polyisocyanate compounds having two or more isocyanate groups. The polyisocyanate compound is not particularly limited, but when used outdoors, it is preferable to use only an alicyclic or aliphatic compound in order to prevent the coating film from deteriorating over time.
Examples of the alicyclic polyisocyanate compound include isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4'-diphenylmethane diisocyanate and the like.
Examples of the aliphatic polyisocyanate compound include trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate.
Examples of the aromatic polyisocyanate compound include diphenylmethane diisocyanate, toluylene diisocyanate, naphthylene-1,5-diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenyl. Examples include isocyanate.
As the polyisocyanate compound, a bi-terminal isocyanate adduct, a biuret-modified product, or an isocyanurate-modified product of the above compound and glycols or diamines may be used.
In particular, when the polyisocyanate compound contains an isocyanurate modified product, particularly an isocyanurate ring-containing triisocyanate, sufficient coating film strength can be obtained after hot pressing, which is preferable. Specific examples of the isocyanurate ring-containing triisocyanate include isocyanurate-modified isophorone diisocyanate (for example, Death Module Z4470 manufactured by Sumitomo Bayer Urethane Co., Ltd.) and isocyanurate-modified hexamethylene diisocyanate (for example, Sumijur manufactured by Sumitomo Bayer Urethane Co., Ltd.). N3300), isocyanurate-modified tolylene diisocyanate (for example, Sumijour FL-2, FL-3, FL-4, HLBA manufactured by Sumitomo Bayer Urethane Co., Ltd.).
The total number of isocyanate groups of the polyisocyanate compound is preferably 0.1 to 5.0 times, more preferably 0.5 to 3.0 times, based on the total number of binder resin functional groups, depending on the required performance. One kind or a mixture of two or more kinds can be used at a ratio of times, particularly preferably 0.8 to 2.0 times.

The binder resin may be in the form of either a soluble resin that dissolves in a solvent or a dispersed resin fine particles (emulsion) that does not dissolve in the solvent and exists in the state of fine particles.

The particle structure of the dispersed resin fine particles may be a multilayer structure, so-called core-shell particles. For example, by localizing a resin in which a monomer having a functional group is mainly polymerized in the core portion or the shell portion, or by providing a difference in Tg and composition between the core and the shell, curability and drying are performed. It is possible to improve the property, film forming property, and mechanical strength of the binder. The average particle size of the resin fine particles is preferably 10 to 1000 nm, preferably 10 to 300 nm, from the viewpoint of binding properties and particle stability. Further, if a large amount of coarse particles exceeding 1 μm is contained, the stability of the particles is impaired, so that the amount of coarse particles exceeding 1 μm is preferably 5% or less at most.
The above average particle size represents a volume average particle size and can be measured by a dynamic light scattering method. The average particle size can be measured by the dynamic light scattering method as follows. Dilute 200 to 1000 times with the same dispersion as the dispersion medium, depending on the solid content of the resin fine particles. Approximately 5 ml of the diluted dispersion is injected into a cell of a measuring device (Nanotrack manufactured by Nikkiso Co., Ltd.), the refractive index conditions of the dispersion medium and the resin corresponding to the sample are input, and then the measurement is performed. It can be measured by the peak of the volume particle size distribution data (histogram) obtained at this time.
The dispersed resin fine particles preferably include crosslinked resin fine particles. The crosslinked resin fine particles indicate resin fine particles having an internal crosslinked structure (three-dimensional crosslinked structure), and it is important that the particles are crosslinked inside the particles. Further, the crosslinked resin fine particles containing a specific functional group can contribute to the adhesion to the substrate. Furthermore, by adjusting the crosslinked structure and the amount of functional groups, a coating film having excellent durability can be obtained.

From the viewpoint of environmental load and the like, a water-based solvent, preferably a water-soluble resin and water-based resin fine particles that can be used in water are preferable. Further, from the viewpoint of slurry stability and coatability of the conductive composition, it is more preferable to use the water-soluble resin and the water-based resin fine particles in combination.

[Water-soluble resin]
The water-soluble resin is a resin that can be completely dissolved in water without separation and precipitation after 1 g of the resin is put in 99 g of water at 25 ° C., stirred, and left at 25 ° C. for 24 hours. Since the water-soluble resin has the effect of enhancing the dispersibility of the carbon material, a stable composition can be obtained with a small amount of resin.
Water-soluble resins are roughly classified into anionic resins, cationic resins, amphoteric resins having both anionic and cationic properties, and other nonionic resins, and the resins are further composed of a plurality of monomers. May be good. Further, the water-soluble resin may be used alone or in combination of two or more.
Examples of the anionic resin include a resin containing a carboxyl group, a sulfo group, a phosphoric acid group, and a skeleton in which some or all of them are neutralized. For example, homopolymers of polymerizable monomers such as (meth) acrylic acid, itaconic acid, fumaric acid, maleic acid, 2-sulfoethylmethacrylate, 2-methacryloyloxyethyl acid phosphate, or other polymerizable single amounts. Examples thereof include copolymers with the body, carboxymethyl cellulose, and alkali-neutralized products thereof.
Examples of the cationic resin include an amino group containing a cyclic substance, a skeleton in which a part or all of the amino group is neutralized, a resin containing a quaternary ammonium salt, and the like. For example, homopolymers of polymerizable monomers such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethyl (meth) acrylate, vinylpyridine, or co-polymerization with other polymerizable monomers. Examples include polymers and their acid-neutralized products.
Examples of the amphoteric resin include a resin containing both the anionic skeleton and the cationic skeleton. Examples thereof include a copolymer of styrene-maleic acid-N, N-dimethylaminoethyl (meth) acrylate.
The nonionic resin is a resin other than the anionic, cationic and amphoteric resins. Examples thereof include polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl butyral, polyacrylamide, poly-N-vinylacetamide, polyalkylene glycol and the like.
The molecular weight of the water-soluble resin is not particularly limited, but the mass average molecular weight is preferably 5,000 to 2,500,000. The mass average molecular weight (Mw) indicates a polyethylene oxide-equivalent molecular weight in gel permeation chromatography (GPC).

[Aqueous resin fine particles]
Aqueous resin fine particles (aqueous emulsions) are dispersed resin fine particles in which the resin does not dissolve in water and exists in the form of fine particles. For example, (meth) acrylic emulsion, nitrile emulsion, urethane emulsion, and polyolefin emulsion. , Fluorine-based emulsions (polyfluoride vinylidene (PVDF), polytetrafluoroethylene (PTFE), etc.), diene-based emulsions (styrene-butadiene rubber (SBR), etc.). In addition, (meth) acrylic means methacryl or acrylic.
When a coating film is formed, the conductive composition containing the water-based resin fine particles has excellent adhesion between the particles and the substrate, and can provide a high-strength coating film. Further, since the adhesiveness is excellent, a small amount of water-based resin fine particles is required, and as a result, the conductivity of the conductive composition is improved. In order to obtain the above-mentioned effects, as the aqueous resin fine particles, a (meth) acrylic emulsion or a urethane emulsion having excellent binding properties and flexibility (flexibility of the film) between the particles is preferable.

The (meth) acrylic emulsion is an emulsion polymer containing 10 parts by mass or more of a monomer having a (meth) acryloyl group, preferably 20 parts by mass or more, and more preferably 30 parts by mass or more. It is good. Since the monomer having an acryloyl group has excellent reactivity, resin fine particles can be produced relatively easily. Therefore, the (meth) acrylic emulsion is particularly preferable as the aqueous resin fine particles.

<Solvent>
In the conductive composition of the present invention, a solvent can be appropriately used when the carbon material is dispersed or when the carbon material and the binder resin are uniformly mixed. Such a solvent is not particularly limited as long as it can dissolve a resin or stably disperse a resin fine particle emulsion, and examples thereof include water and an organic solvent.

Organic solvents include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether and diethylene glycol methyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and the like. Suitable for the composition of the conductive composition from among ethers, hydrocarbons such as hexane, heptane and octane, aromatics such as benzene, toluene, xylene and cumene, and esters such as ethyl acetate and butyl acetate. Can be used.
Further, the solvent may be a combination of water and an organic solvent, or two or more kinds of organic solvents may be used in combination.

When a water-soluble resin or water-based resin fine particles are used, it is preferable to use water as a solvent from the viewpoint of solubility and dispersibility, and if necessary, a liquid medium compatible with water may be added. As the liquid medium compatible with water, an alcohol solvent having 4 or less carbon atoms is preferable.
Further, the conductive composition of the present invention may contain, if necessary, an ultraviolet absorber, an ultraviolet stabilizer, a radical catching agent, a filler, a thixotropic agent, an antistatic agent, as long as the effect of the present invention is not impaired. Antioxidants, antistatic agents, flame retardants, thermal conductivity improvers, plasticizers, anti-sag agents, antifouling agents, preservatives, bactericides, defoamers, leveling agents, anti-blocking agents, hardening agents, thickening agents Various additives such as agents, dispersants, and silane coupling agents may be added.

<Conductive aid>
The conductive composition of the present invention may further contain a conductive auxiliary agent other than the carbon material of the present invention, if necessary. The conductive auxiliary agent may be any material that does not correspond to the specific boron-containing carbon material of the present invention, for example, carbon black, activated carbon, graphite, conductive carbon fiber (carbon nanotube, carbon nanofiber, etc.), carbon nanohorn, graphene. , Graphene nanoplatelets, carbon auxiliaries such as nanoporous carbon, and metal auxiliaries such as metal nanoparticles (silver, copper, etc.).
The conductive auxiliary agent may contain boron or may be doped with boron. When the conductive auxiliary agent contains boron, the content of boron in the conductive auxiliary agent is preferably 0.01 to 2 mol%, more preferably 0.1 to 1 mol%. When the content of boron in the conductive auxiliary agent is 0.01 to 2 mol%, the wettability to the solvent and the binder resin is increased, and the hardness of the conductive auxiliary agent is increased, so that the dispersibility of the conductive composition is increased. And the durability against external force such as impact is improved, so that the dispersion stability and the film strength are improved.

From the viewpoint of specific surface area and particle size, carbon black is preferable as the conductive auxiliary agent. The carbon black, activated carbon, graphite, conductive carbon fiber (carbon nanotube, carbon nanofiber, etc.), carbon nanohorn, graphene, graphene nanoplatelet, and nanoporous carbon that can be used as carbon auxiliaries are those described above. Can be used.

The conductive auxiliary agent preferably has a larger specific surface area than the carbon material of the present invention, which is the conductive main agent. The specific surface area of the conductive auxiliary agent is preferably 10 to 1500 m ² / g, more preferably 100 to 1300 m ² / g, and further preferably 150 to 550 m ² / g. When the specific surface area of the conductive auxiliary agent is 1500 m ² / g or less, the dispersibility of the conductive composition is good, and when the specific surface area is 10 m 2 / g or more, the gaps between the conductive main agents in the conductive film are efficiently filled. It is possible to obtain a conductive film having excellent conductivity and durability.
The specific surface area of the present invention refers to the specific surface area (BET) obtained from the amount of nitrogen adsorbed.

The ratio of the boron-containing carbon material to the total solid content of the conductive composition is preferably 60 to 99% by mass, and more preferably 65 to 85% by mass.
When the conductive composition further contains a conductive auxiliary agent, the ratio of the boron-containing carbon material to the total solid content of the conductive composition is preferably 40 to 85% by mass, more preferably 45 to 75% by mass. Yes, more preferably 50-60% by mass.
On the other hand, the ratio of the conductive auxiliary agent to the total solid content of the conductive composition is preferably 5 to 20% by mass, more preferably 8 to 20% by mass, and further preferably 10 to 18% by mass. .. When the ratios of the carbon material and the conductive auxiliary agent to the total solid content of the conductive composition are 50 to 60% by mass and 10 to 18% by mass, respectively, the dispersibility of the conductive composition is very good and the conductive composition is conductive. It is possible to obtain a conductive film having particularly excellent durability.

The viscosity of the conductive composition can be appropriately adjusted by the coating method of the conductive composition, but it is generally preferably 10 mPa · s or more and 30,000 mPa · s or less. The viscosity can be measured using, for example, a B-type viscometer.
Since the viscosity of the dispersion containing the boron-containing carbon auxiliary as the conductive auxiliary agent has changed as described above, the surface state of the carbon auxiliary has changed, so that the viscosity of the dispersion is compared with the case where the dispersion is prepared as the boron-free carbon auxiliary. , The viscosity tends to decrease, and the effect of facilitating the handling of the dispersion can be seen.

(Disperser / Mixer)
As an apparatus used for obtaining the conductive composition, a disperser or a mixer usually used for pigment dispersion or the like can be used.

For example, mixers such as disper, homomixer, or planetary mixer; homogenizers such as "Clairemix" manufactured by M-Technique or "Philmix" manufactured by PRIMIX; paint conditioner (manufactured by Red Devil), ball mill, sand mill. Media type disperser such as (Symmal Enterprises "Dyno Mill" etc.), Atreiter, Pearl Mill (Eirich "DCP Mill" etc.), or Coball Mill; Wet Jet Mill (Genus PY "Genus PY", Sugino Medialess disperser such as Machine's "Starburst", Nanomizer's "Nanomizer", etc.), M-Technique's "Claire SS-5", or Nara Machinery's "MICROS"; or other roll mills, kneaders , Ultrasonic disperser, etc., but is not limited thereto.

For example, when using a media-type disperser, a method in which the agitator and vessel use a disperser made of ceramic or resin, or a disperser in which the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. It is preferable to use. As the medium, it is preferable to use glass beads, zirconia beads, or ceramic beads such as alumina beads. As the dispersive device, only one type may be used, or a plurality of types of devices may be used in combination.

<Conductor>
The conductive film of the present invention is a film formed of a conductive composition, and can be formed by applying the conductive composition on a substrate and drying it if necessary.

(Base material)
The shape of the base material used for forming the conductive film is not particularly limited, and a material suitable for the intended use can be appropriately selected. The base material is preferably in the form of a sheet, and more preferably an insulating resin film.

The material of the base material is not particularly limited, and examples thereof include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, polyvinyl chloride, polyamide, nylon, OPP (stretched polypropylene), and CPP (unstretched polypropylene). ..

As the shape, a film on a flat plate is generally used, but a film having a roughened surface, a primer-treated film, a perforated film, and a mesh-like substrate can also be used.

The method for applying the conductive composition on the substrate is not particularly limited, and a known method can be used. Examples of such a coating method include a die coating method, a dip coating method, a roll coating method, a doctor coating method, a knife coating method, a spray coating method, a gravure coating method, a screen printing method, and an electrostatic coating method. Be done. Examples of the drying method include, but are not limited to, neglected drying, blast drying, warm air drying, infrared heating, and far infrared heating.

Further, after coating, a rolling process such as a lithographic press or a calendar roll may be performed, and the rolling process may be performed while heating in order to soften the conductive film and facilitate pressing.
The thickness of the conductive film is generally 0.1 μm or more and 1 mm or less, preferably 1 μm or more and 200 μm or less.

(Volume resistivity of conductive film)
The volume resistivity of the conductive film of the present invention is preferably ^{less than 5 × 10 -3} Ω · cm, more preferably less than 3 × 10 ^-3 Ω · cm, still more preferably 2 × 10 ^-3 Ω · cm. It is less than cm. Since the volume resistivity is ^{less than 5 × 10 -3} Ω · cm, it can be used as a highly conductive composition for battery electrodes, current collectors and batteries, wiring of electronic devices, and the like.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the scope of rights of the present invention in any way. In the examples and comparative examples, "parts" represents "parts by mass" and "%" represents "% by mass".

<Manufacturing of carbon materials>
<Example 1>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and boric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 80/20 (spheroidized graphite / boric acid), and rotate and revolve. After mixing with a mixer, the mixture was compounded with a particle compounding device Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2100 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (1).
The [XY], G / D ratio, amount of substituted boron element, and volume resistivity of the boron-containing carbon material (1) were obtained according to the calculation method described later, and were 225.3 cm ^-1 1.8, respectively. , 0.0027, 4.1 × 10 ^-4 Ω · cm.

<Example 2>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 97/3 (spheroidized graphite / boric acid), and used as a solvent. Water was added, the mixture was mixed with a rotation / revolution mixer, and dried in an oven at 80 ° C. under the atmosphere to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2100 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (2).
Boron [X-Y] carbon-containing material (2), G / D ratio, substitutional boron element content, respectively a volume resistivity 219.2cm ^-1, 6.2,0.0003,9.1 × 10 ^{- It was 4} Ω · cm.

<Example 3>
Artificial graphite PAG-5 (manufactured by Nippon Graphite Industry Co., Ltd.) and boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 80/20 (artificial graphite / boric acid), and a particle compounding device is used. Complexation was carried out with Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2100 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (3).
Boron [X-Y] carbon-containing material (3), G / D ratio, substitutional boron element content, respectively a volume resistivity 221.4cm ^-1, 1.4,0.0052,7.9 × 10 ^{- It was 4} Ω · cm.

<Example 4>
Natural graphite FB-150 (manufactured by Nippon Graphite Industry Co., Ltd.) and boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 80/20 (natural graphite / boric acid), and a particle compounding device is used. Complexation was carried out with Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2100 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (4).
Boron [X-Y] carbon-containing material (4), G / D ratio, substitutional boron element content, respectively a volume resistivity 221.8cm ^-1, 1.5,0.0036,6.9 × 10 ^{- It was 4} Ω · cm.

<Example 5>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and boron carbide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 96/4 (spheroidized graphite / boron carbide), and used as a solvent. After adding water, glass beads were added, mixed using a paint shaker, and dried in an oven at 80 ° C. in the air to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2900 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (5).
Boron [X-Y] carbon-containing material (5), G / D ratio, substitutional boron element content, respectively a volume resistivity 225.4cm ^-1, 1.3,0.0080,5.7 × 10 ^{- It was 4} Ω · cm.

<Example 6>
Boron carbide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) and toluene as a solvent are added, then alumina beads are added, crushed using a paint shaker, and dried in an oven at 80 ° C. in the air to obtain crushed boron carbide. rice field. Next, the spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and the pulverized boron carbide are weighed so as to have a mass ratio of 99.1 / 0.9 (spheroidized graphite / boron carbide), and the particles are obtained. Complexing device Mechanofusion (manufactured by Hosokawa Micron Co., Ltd.) was used for compositing to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2000 ° C. for 1.5 hours in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (8).
Boron [X-Y] carbon-containing material (8), G / D ratio, substitutional boron element content, respectively a volume resistivity 222.6cm ^-1, 3.0,0.0005,2.8 × 10 ^{- It was 4} Ω · cm.

<Example 7>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 85/15 (spheroidized graphite / boric acid), and put into a ball mill. After pulverizing and mixing, the mixture consisting of spheroidized graphite / boric acid was separated and taken out, and composited with a particle compounding device Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2050 ° C. for 2 hours in an argon atmosphere in a multipurpose high temperature furnace to obtain a boron-containing carbon material (9).
The [XY], G / D ratio, amount of substituted boron element, and volume resistivity of the boron-containing carbon material (9) are 224 cm ^-1 1.7, 0.0046, 3.8 × 10 ^-4 Ω, respectively. -It was cm.

<Example 8>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Industry Co., Ltd.) and boron carbide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 97/3 (spheroidized graphite / boron carbide), and put into a ball mill. After pulverizing and mixing, the mixture composed of spheroidized graphite / boron carbide was separated and taken out, and composited with a particle compounding device Mechanofusion (manufactured by Hosokawa Micron) to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 2200 ° C. for 1.5 hours in an argon atmosphere in a multipurpose high-temperature furnace to obtain a boron-containing carbon material (10).
Boron [X-Y] carbon-containing material (10), G / D ratio, substitutional boron element content, respectively a volume resistivity 222.3cm ^-1, 1.5,0.0055,3.7 × 10 ^{- It was 4} Ω · cm.

<Comparative Example 1>
Spheroidized graphite CGB-50 (manufactured by Nippon Graphite Co., Ltd.) was used as the carbon material (6).
[XY] of carbon material (6), G / D ratio, amount of substituted boron element, volume resistivity are 230 cm ^-1 , 5.0, respectively, below the lower limit of detection (≦ 0.0001), 2.0 × It was 10 ^-3 Ω · cm.

<Comparative Example 2>
Multi-walled carbon nanotubes (MWCNT) NTP3003 (manufactured by NTP) and boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) are weighed so as to have a mass ratio of 90/10 (MWCNT / boric acid), and mixed in a mortar. , A mixture was obtained. The above mixture was filled in a graphite crucible and heat-treated at 2200 ° C. for 1 hour in an argon atmosphere in a multipurpose high temperature furnace to obtain a boron-containing carbon material (7).
The [XY], G / D ratio, amount of substituted boron element, and volume resistivity of the boron-containing carbon material (7) are 232 cm ^-1 , 0.8, 0.001, 7.3 × 10 ^-3 Ω, respectively. -It was cm.

<Comparative Example 3>
92.5 parts of petroleum coke, which is a carbon source, and 7.5 parts of boron oxide (manufactured by Wako Pure Chemical Industries, Ltd.), which is a boron source, are mixed in a Menou dairy pot, filled in a graphite rutsubo, and argon in a firing furnace. The heat treatment was carried out at 2900 ° C. for 2 hours in an atmosphere to obtain a boron-containing carbon material (11).
Boron [X-Y] carbon-containing material (11), G / D ratio, substitutional boron element content, respectively a volume resistivity 227.2cm ^-1, 7.0,0.0011,2.3 × 10 ^{- It was 3} Ω · cm.

<Evaluation of carbon materials>
The physical properties of the produced boron-containing carbon material were evaluated by the following method.

<Difference in Raman shift [XY]>
[XY] was evaluated using a laser Raman spectrophotometer NRS-3100 manufactured by JASCO Corporation. ^{Raman shift at the peak top of the D band (1330-1370 cm -1} ) and Raman at the peak top of the G band (1560-1620 cm ^-1 ) of the Raman spectrum of each sample measured under the condition of an excitation laser wavelength of 532 nm. [XY] was calculated from the shift difference.

<G / D ratio>
The G / D ratio was evaluated using a laser Raman spectrophotometer NRS-3100 manufactured by JASCO Corporation. Measured under the condition of an excited laser wavelength of 532 nm, from the ratio (IG / ID) of the peak intensities of ^{the D band (1330-1370 cm -1} ) and the G band (1560-1620 cm ^{-1) of the Raman spectrum of each sample obtained.} The G / D ratio was calculated.

<Amount of total surface boron element, amount of surface-replacement type boron element>
The total amount of surface boron element and the amount of surface-substituted boron element were evaluated using a K-Alpha manufactured by Thermo Fisher scientific company, an X-ray photoelectron spectroscope. The ratio (molar ratio) of the total surface boron elements was calculated from the total spectral area obtained from the boron B1s spectral peak. Further, the ratio (molar ratio) of the surface-substituted boron element was calculated from the ratio of the peak area of 188 to 189.3 eV to the total spectral area of the boron.

<Volume resistivity>
The volume resistivity was evaluated using a powder resistivity measuring system MCP-PD51 manufactured by Nittoseiko Analytech.
The measurement was performed by a four-probe method using a powder probe for low resistance, and the volume resistivity when a load of 20 kN was applied to each sample was used as a value.

Table 1 shows the physical characteristics of the boron-containing carbon material produced above.

From Table 1, it was confirmed that the volume resistivity was improved (lower resistance) in each of the examples as compared with the comparative example. This is because the difference in Raman shift [XY] is within the range of the present invention, so that the carrier density can be improved by doping the carriers and the crystallinity (number of carbon layers) can be maintained. It is considered that the electron conductivity was improved as compared with the above.
As described above, it has been clarified that remarkable high conductivity can be exhibited by appropriately controlling the difference in Raman shift [XY] within the range of the present invention.

<Manufacturing of binder resin>
[Production Example 1] Obtained from terephthalic acid, adipic acid, and 3-methyl-1,5-pentanediol in a reaction vessel equipped with a polyurethane resin solution stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. 455.5 parts of polyester polyol (“Kurare polyol P-2011” manufactured by Kurare Co., Ltd., Mn = 2,011), 16.5 parts of dimethylolbutanoic acid, 105.2 parts of isophorone diisocyanate, and 140 parts of toluene are charged. The reaction was carried out at 90 ° C. for 3 hours under a nitrogen atmosphere, and 360 parts of toluene was added thereto to obtain a urethane prepolymer solution having an isocyanate group.
Next, a urethane prepolymer solution having an isocyanate group obtained by mixing 19.9 parts of isophorondiamine, 0.63 parts of di-n-butylamine, 294.5 parts of 2-propanol, and 335.5 parts of toluene. 969.5 parts were added (the total equivalent of amino groups to the free isocyanate groups at both ends of the urethane prepolymer is 0.98), reacted at 50 ° C for 3 hours, followed by 70 ° C. The reaction was carried out for 2 hours and diluted with 126 parts of toluene and 54 parts of 2-propanol to obtain a solution of a polyurethane resin having a weight average molecular weight of 61,000 and an acid value of 10 mgKOH / g.
The obtained polyurethane resin solution was diluted with toluene / methyl ethyl ketone / 2-propanol (mass ratio: 1/1/1) to obtain a polyurethane resin solution having a solid content of 20% by mass.

[Production Example 2] Prepole 1009 (hydrophobic dimer acid, Croder Japan Co., Ltd.) as a polybasic acid compound in a 4-necked flask equipped with a polyamide resin solution stirrer, a reflux cooling tube, a nitrogen introduction tube, an introduction tube, and a thermometer. 156.2 parts, 5-hydroxyisophthalic acid 5.5 parts, preamine 1074 (manufactured by Croder Japan Co., Ltd.) 146.4 parts as a polyamine compound, 100 parts ion-exchanged water, and the temperature of heat generation is constant. It was stirred until it became. When the temperature became stable, the temperature was raised to 110 ° C, and after confirming the outflow of water, the temperature was raised to 120 ° C 30 minutes later, and then the dehydration reaction was continued while raising the temperature by 10 ° C every 30 minutes. .. After the temperature reached 230 ° C., the reaction was continued at that temperature for 3 hours and kept under a vacuum of about 2 kPa for 1 hour to lower the temperature. Finally, an antioxidant was added to obtain a polyamide resin having a weight average molecular weight of 24,000, an acid value of 13.2 mgKOH / g, a hydroxyl value of 5.5 mgKOH / g, and a glass transition temperature of −32 ° C.
The obtained polyamide resin was diluted with toluene / 2-propanol (mass ratio: 2/1) to obtain a polyamide resin solution having a solid content of 20% by mass.

[Production Example 3] Polyester resin solution Byron 200 (polyester resin manufactured by Toyobo Co., Ltd.) was diluted with toluene / methyl ethyl ketone (mass ratio: 1/1) to obtain a polyester resin solution having a solid content of 20% by mass.

The resin was evaluated as follows.
(Weight average molecular weight (Mw))
The weight average molecular weight was measured by using gel permeation chromatography (GPC) "HPC-8020" manufactured by Tosoh Corporation. GPC is a liquid chromatography in which a substance dissolved in a solvent (THF; tetrahydrofuran) is separated and quantified according to the difference in molecular size. In the measurement in the present invention, two "LF-604" (manufactured by Showa Denko KK: GPC column for rapid analysis: 6 mm ID x 150 mm size) are connected in series to the column, the flow rate is 0.6 ml / min, and the column temperature is set. It was carried out under the condition of 40 ° C., and the weight average molecular weight was determined in terms of polystyrene.

(Acid value (AV))
Approximately 1 g of the sample was precisely weighed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Phenolphthalein test solution was added to this as an indicator and held for 30 seconds. Then, the solution was titrated with a 0.1N alcoholic potassium hydroxide solution until the solution turned pink, and the acid value was determined by the following formula.
Acid value (mgKOH / g) = (5.611 × a × F) / S However,
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
F: Titer of 0.1N alcoholic potassium hydroxide solution

(Hydroxy group value (OHV))
The hydroxyl value is the amount of hydroxyl group contained in 1 g of a hydroxyl group-containing resin expressed by the amount of potassium hydroxide (mg) required to neutralize acetic acid bonded to the hydroxyl group when the hydroxyl group is acetylated. Is. The hydroxyl value was measured according to JISK0070, and in the present invention, it was determined in consideration of the acid value as shown in the following formula.
Approximately 1 g of the sample was precisely weighed in a stoppered Erlenmeyer flask, and 100 ml of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Further, exactly 5 ml of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 ml) was added, and the mixture was stirred for about 1 hour. Phenolphthalein test solution was added to this as an indicator and lasted for 30 seconds. Then, the solution was titrated with a 0.1N alcoholic potassium hydroxide solution until the solution turned pink, and the hydroxyl value was determined by the following formula.
Hydroxy group value (mgKOH / g) = [{(ba) × F × 28.05} / S] + D
However,
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)
b: Consumption (ml) of 0.1N alcoholic potassium hydroxide solution in the blank experiment
F: Titer of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)

(Glass transition temperature (Tg))
The glass transition temperature of the resin was measured by using a resin obtained by removing the solvent by drying and using "DSC-1" manufactured by METTLER TOLEDO Co., Ltd., and raising the temperature from -80 to 150 ° C. at 2 ° C./min.

<Manufacturing of conductive auxiliary agent>
[Manufacturing Example 4] CB (A)
Add 600 parts of toluene and 300 parts of ethanol as solvents to 90 parts of EC-300J (Ketchen Black, manufactured by Lion Specialty Chemicals) and 10 parts of boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), and rotate. The mixture was mixed with a revolution mixer and dried in an oven at 80 ° C. under the air to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 1900 ° C. for 1 hour in an argon atmosphere in a multipurpose high-temperature furnace to obtain CB (A).
The [XY] of CB (A) was 235 cm ^-1 . The boron content was 1.06 mol%. The boron content is a value measured in a carbon material using ICP emission spectroscopic analysis (SPECTROARCOS FHS12 manufactured by SPECTRO). The specific surface area was 230 m ² / g. The nitrogen adsorption amount was measured using a gas adsorption amount measuring device (BELSORP-mini manufactured by Microtrac Bell), and the specific surface area was calculated by the BET method.

[Manufacturing Example 5] CB (B)
To 94 parts of EC-600J (Ketchen Black, manufactured by Lion Specialty Chemicals Co., Ltd.) and 6 parts of boric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), 500 parts of toluene and 500 parts of ethanol, which are solvents, are added to rotate. The mixture was mixed with a revolution mixer and dried in an oven at 80 ° C. under the air to obtain a mixture. The above mixture was filled in a graphite crucible and heat-treated at 1680 ° C. for 2 hours in an argon atmosphere in a multipurpose high-temperature furnace to obtain CB (B).
The [XY] of CB (A) was 237 cm ^-1 . The boron content was 0.73 mol% and the specific surface area was 350 m ² / g.

[Manufacturing Example 6] CNT
A catalyst for CNT synthesis was prepared by the method described in paragraphs [0147] and [0148] of JP-A-2019-108256. After that, a quartz glass bakeware sprayed with 1 g of the CNT synthesis catalyst was installed in the center of a horizontal reaction tube having an internal volume of 10 L, which could be pressurized and heated by an external heater. Exhaust was performed while injecting nitrogen gas, the air in the reaction tube was replaced with nitrogen gas, and the mixture was heated until the atmospheric temperature in the horizontal reaction tube reached 700 ° C. After reaching 700 ° C., ethylene gas as a hydrocarbon was introduced into the reaction tube at a flow rate of 2 L / min, and the contact reaction was carried out for 15 minutes. After completion of the reaction, the gas in the reaction tube was replaced with nitrogen gas, and the temperature of the reaction tube was cooled to 100 ° C. or lower and taken out to obtain CNTs. The specific surface area was 630 m ² / g.

<Manufacturing of conductive compositions and conductive films>
[Example A1]
Put 84 parts of carbon material (1), 80 parts of polyester resin solution as binder resin (16 parts of resin solid content), and 180 parts of toluene / methyl ethyl ketone / 2-propanol (mass ratio: 1/1/1) as solvent in a mixer. The mixture was further mixed and further put into a sand mill for dispersion to obtain a conductive composition (1). Next, this conductive composition (1) was applied onto a PET film substrate having a thickness of 100 μm using a doctor blade, and then dried in an oven. Then, a roll press was performed under the condition of a linear pressure of 300 kg / cm to obtain a conductive film (1).

[Examples A2 to A4, Comparative Examples A1 to A3]
Conductive compositions (2) to (7) and conductive films (2) to (7) were obtained by the same method as in Example A1 except that the composition was changed to that shown in Table 2.

[Example A5]
Carbon material (1) 60.8 parts, CB (1) 9.2 parts as a conductive auxiliary agent, polyamide resin solution 150 parts (resin solid content 30 parts) as a binder resin, toluene / methyl ethyl ketone / 2-propanol (mass) as a solvent The ratio: 1/1/1) was put into a mixer and mixed so that the solid content in the composition was 30% by mass, and further put into a sand mill for dispersion to obtain a conductive composition (8). Next, this conductive composition (8) was applied onto a PET film substrate having a thickness of 100 μm using a doctor blade, and then dried in an oven to obtain a conductive film (8).

[Examples A6 to A18, Comparative Examples A4 to A6]
Conductive compositions (9) to (21), (23) to (25), conductive films (9) to (21), by the same method as in Example A5 except that the composition was changed to the composition shown in Table 2. (23) to (25) were obtained.

[Example A19]
57 parts of carbon material (4), 18 parts of CB (2) (acetylene black HS-100, manufactured by Denka Co., Ltd.) as a conductive auxiliary agent, and 2 parts of water-soluble resin CMC (manufactured by Daicel FineChem, carboxymethyl cellulose # 1240) as a binder resin. 250 parts of a mass-% dissolved aqueous solution (5 parts of resin solid content) was put into a mixer to mix, and further put into a sand mill for dispersion.
Next, 40 parts (20 parts by mass of solid content) of aqueous resin fine particles (polyacrylic emulsion W-168, manufactured by Toyochem Co., Ltd., solid content 50% by mass) were added as a binder resin and mixed with a mixer to form a conductive composition (conducting composition). 22) was obtained.
Next, this conductive composition (22) was applied onto a PET film substrate having a thickness of 100 μm using a doctor blade, and then dried in an oven to obtain a conductive film (22).

<Evaluation of conductive composition and conductive film>
The obtained conductive composition and conductive film were evaluated by the following methods. The evaluation results are shown in Table 2.

[Dispersion stability evaluation]
The dispersion stability was evaluated from the change in liquid properties after the conductive composition was allowed to stand at 25 ° C. for 7 days and stored. The change in liquid properties was judged from the ease of stirring with a spatula.
◯: No change in liquid properties (good)
Δ: Viscosity has increased, but gelation has not occurred (possible)
×: Gelled (defective)

[Evaluation of coatability]
The obtained conductive film was observed with a video microscope VHX-900 (manufactured by KEYENCE CORPORATION) at a magnification of 500, and coating unevenness and pinholes were judged according to the following criteria. The coating unevenness was judged by the shading of the film surface. Pinholes were determined by the presence or absence of uncoated defects in the membrane.
《Uneven coating》
◯: The shading of the film surface is not confirmed (good)
Δ: There are 2 to 3 shades on the film surface, but it is an extremely small area (possible).
X: Many shades on the film surface are confirmed, or one or more shades with a stripe length of 5 mm or more are confirmed (defective).
《Pinhole》
◯: No pinhole is confirmed (good)
Δ: There are 2 to 3 pinholes, but they are extremely small (possible).
X: Many pinholes are confirmed, or one or more pinholes with a diameter of 1 mm or more are confirmed (defective).

[Volume resistivity of membrane]
The volume resistivity of the conductive film was measured by the 4-terminal method using Lorester GP (manufactured by Nittoseiko Analytech Co., Ltd.) in accordance with JIS-K7194.

[Membrane durability]
The durability of the conductive film was evaluated by scratch hardness (pencil method) using a pencil having a hardness of HB in accordance with JIS K5600-5-4: 1999.
〇: Plastic deformation and cohesive fracture do not occur (good)
Δ: Plastic deformation or cohesive fracture is partially occurring (possible)
×: Plastic deformation and cohesive fracture have occurred (defective)

According to the results in Table 2, the conductive composition using the boron-containing carbon material of the present invention has excellent dispersion stability and coatability, and the conductive film formed from the conductive composition. Has both high conductivity and durability.
Further, from the comparison of Examples A3 and A4 and Examples A11 and A12, it was shown that the order of conductivity in the carbon material and the order of conductivity in the conductive film do not always match.
Further, from the comparison of Examples A5 to A9, even when the same carbon material is used, the coatability of the conductive composition and the characteristics of the conductive film are different depending on the type and the blending ratio of the conductive auxiliary agent. It was shown to fluctuate.
Focusing on the conductive auxiliary agent, from the comparison of Examples A13 to A16, the specific surface area of the conductive auxiliary agent and the content of the substituted boron in the conductive auxiliary agent are the coatability of the conductive composition and the conductive material. It has been shown to affect conductivity.
These results suggest that factors other than carbon materials are involved. Although the details are unknown at this stage, in the conductive composition of the present invention, not only the boron-containing carbon material itself is excellent in conductivity, but also the dispersibility and dispersion stability are good, and the coatability is also good. Therefore, it is presumed that the carbon material efficiently forms a conductive network in the film to exhibit excellent conductivity. In addition, it is presumed that the uniform network of carbon materials led to the improvement of the durability of the conductive film.
Further, the boron-containing carbon material of the present invention not only improves the wettability with respect to a solvent or a binder resin, but also tends to increase the hardness of the carbon material, which affects dispersibility and coatability. Conceivable. As a result, it is presumed that the conductive composition containing the boron-containing carbon material has improved dispersibility and coatability, and exhibits excellent conductivity.

1: Peak of boron cluster (186 to 187 eV) 2: Peak of boron carbide (187 to 188 eV) 3: Boron (188 to 189.3 eV) doped so as to replace a carbon element having a hexagonal network surface as a basic skeleton ) Peak 4: Boron BC ₂ O (189.5 to 190.5 eV) peak 5: Boron BCO ₂ (191.5-192 eV) peak 6: Boron B ₂ O ₃ (192.5-193 eV) ) Peak

Claims (8)

A boron-containing carbon material in which a boron element is doped so as to replace at least a part of the carbon element in the carbon skeleton, in which the G-band Raman shift in the laser Raman spectrum is X and the D-band Raman shift is Y. The difference in Raman shift [XY] is 226 cm ^-1 or less, and the ratio of surface-substituted boron elements to all elements on the surface of the boron-containing carbon material measured by X-ray photoelectron spectroscopy (XPS) is , 0.0001 or more boron-containing carbon material. The boron-containing carbon material according to claim 1, which comprises at least one selected from the group consisting of a graphite-based carbon material, a graphene-based carbon material, and a carbon nanotube-based carbon material. The boron-containing carbon material according to claim 1 or 2, wherein the intensity ratio [G / D] of the G band to the D band in the laser Raman spectrum is 6 or less. The boron-containing carbon material according to any one of claims 1 to 3, wherein the difference in Raman shift [XY] is 218 to 226 cm ^-1. A conductive composition comprising the boron-containing carbon material according to any one of claims 1 to 4 and at least one of a binder resin or a solvent. The conductive composition according to claim 5, further comprising a conductive auxiliary agent. The conductive composition according to claim 6, wherein the specific surface area of the conductive auxiliary agent is 150 to 550 m ^{2 / g.} A conductive film formed from the conductive composition according to any one of claims 5 to 7.

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