JP6930129B2 - Complex - Google Patents

Description

The present invention relates to a composite composed of carbon nanofibers having a carboxyl group, a cross-linking agent, and a base material.

Currently, various carbon nanofibers typified by carbon nanotubes are being developed. For example, conductive fillers, heat conductive materials, light emitting elements, electrode materials for batteries and capacitors, wiring materials and electrode bonding materials between wirings, reinforcing materials. , Black pigment, etc., are promising as materials having various functions in various applications.

Carbon nanofibers have excellent mechanical properties as well as electrical properties. That is, since it is composed of only carbon atoms, it has a Young's modulus exceeding 1 TPa and is extremely tough, even though it is extremely lightweight. In addition, because it is a cage substance, it is also rich in elasticity and resilience. As described above, carbon nanofibers are attractive substances as industrial materials because they have various excellent properties.

So far, many applied researches utilizing the excellent properties of carbon nanofibers have been conducted. Carbon nanofibers are added as resin reinforcement and conductive composite materials, and they are used as probes for scanning probe microscopes. Further, as a microelectron source, a field emission type electronic device and carbon nanofibers are used as a flat display.

As described above, carbon nanofibers have various applications, but recently, applications as fillers for polymer resins used as various materials have been considered. Conventionally, various fillers have been added in order to impart functions such as conductivity, mechanical strength, and flame retardancy to a polymer.

For example, in the case of imparting conductivity, a conductive filler such as carbon black, carbon fiber, or metal oxide has been blended with a polymer such as polycarbonate or an elastomer such as butadiene rubber. When the compounding of the conductive material is increased in order to impart high conductivity, there have been problems such as a decrease in moldability and a significant decrease in mechanical properties such as impact strength.

In order to solve these problems, recently, vapor phase-grown carbon fibers, carbon nanofibers, and the like have been blended into resins (for example, Patent Documents 1 and 2).

Carbon nanofibers have higher conductivity than conventional carbon-based conductive fillers, and because they have a high aspect ratio, they can easily form a network structure in the resin, and are extremely fine and have a large number of fibers per unit weight. Has. Therefore, it is said that a resin composition having higher conductivity can be obtained when the resin is blended with the same degree as the conventional carbon-based conductive filler.

As the carbon nanotube having a functional group, there is an example of a polymer composite composed of carbon nanotube carboxylic acid methyl ester and polyethylene, polypropylene, polyvinyl chloride, polyamide, polyimide, epoxy resin and the like (Patent Document 3). Further, there is an example composed of carbon nanotubes and a paper fiber material (Patent Document 4).

As a resin fiber containing carbon nanotubes, there is an example in which a resin fiber is produced by using polyvinyl alcohol or polyacrylonitrile as a binder (Patent Document 5).

As for the cloth containing carbon nanotubes, there is an example in which the carbon nanotubes are suspended in a polymer solution and spun in a coagulating liquid to produce a yarn (Patent Document 6). Polyvinyl alcohol is used as this polymer solution. Further, there is an example in which a polyester fiber is coated with a polyurethane resin as a binder (Patent Document 7).

For the base material coated with an ink consisting of carbon nanotubes having a functional group and a cross-linking agent, a dispersion liquid consisting of methyl esterified carbon nanotubes and glycerin is applied to Capton tape and heated at 200 ° C. for 2 hours. There is an example in which a wire is produced by curing (Patent Document 8). In addition to glycerin, polyols, polyamines, and polycarbodiimides have been reported as cross-linking agents.

In these precedent cases, since the carbon nanofibers and the resin are not bonded, there is a problem that the carbon nanofibers fall off from the resin. Similarly, a polymer composite composed of carbon nanotube carboxylic acid methyl ester and polyethylene or the like and a resin fiber containing carbon nanotubes have the same problem. Further, since these cases do not contain a base material, there is a problem that they become brittle as the filling amount of carbon nanofibers increases.

Similarly, for cloths containing carbon nanotubes, the carbon nanotubes and the polymer solution are not bonded in the example in which the carbon nanotubes are suspended in a polymer solution and spun in a coagulating solution to produce threads. Therefore, there is a problem that it falls off, and since there is no base material, it is fragile and easily broken when the filling amount of carbon nanofibers increases. In addition, these materials have problems such as low conductivity.

Further, in the previous case in which the polyester fiber was used as the base material, the carbon nanotube had no reactive functional group, so that it was not bonded to the binder of the polyurethane resin. Moreover, since a polymer binder is used, the conductivity is low.

Similarly, in the previous case where Kapton tape was used as the base material, a dispersion liquid consisting of methyl esterified carbon nanotubes and glycerin was applied to Kapton tape and cured by heating at 200 ° C. for 2 hours to prepare a wire. However, the base material, Kapton tape, is used for molding, and the final product does not contain the base material.

Japanese Unexamined Patent Publication No. 7-102112 Japanese Patent Publication No. 2002-503204 Japanese Unexamined Patent Publication No. 2005-133062 Special Table 2004-524945 Japanese Unexamined Patent Publication No. 2012-167403 Japanese Patent Publication No. 2004-532937 Japanese Unexamined Patent Publication No. 2017-26334 Japanese Unexamined Patent Publication No. 2005-96024

The present invention is a composite composed of a carbon nanofiber having a carboxyl group, a cross-linking agent composed of a specific organic compound, and a base material, which have excellent conductivity, high storage stability, and high film strength after cross-linking. The purpose is to provide.

（式中、Ｘはｎ価の、脂肪族炭化水素基、脂環式炭化水素基、芳香族炭化水素基、脂肪族複素環基または芳香族複素環基を表し、ｎは２〜６の整数であり、
Ｒ¹およびＲ²は、それぞれ独立に、水素原子、一般式（２）で表される基、脂肪族炭化水素基、脂環式炭化水素基または芳香族炭化水素基を表し、Ｒ¹およびＲ²のうち、少なくとも１つは、一般式（２）で表される基である。）
一般式（２）

（式中、Ｒ³〜Ｒ⁶はそれぞれ独立に、水素原子または脂肪族炭化水素基を表す。） That is, the present invention is based on a composition containing carbon nanofibers having a carboxyl group and at least one cross-linking agent selected from the group consisting of a compound represented by the following general formula (1) and an epoxy group-containing compound. The present invention relates to a composite obtained by coating, impregnating or printing on.
General formula (1)

(In the formula, X represents an n-valent aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an aliphatic heterocyclic group or an aromatic heterocyclic group, and n is an integer of 2 to 6. And
R ¹ and R ² independently represent a hydrogen atom, a group represented by the general formula (2), an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and R ¹ and R 2 respectively. of the ^two, at least one is a group represented by the general formula (2). )
General formula (2)

(In the formula, R ^{3 to} R ⁶ independently represent a hydrogen atom or an aliphatic hydrocarbon group.)

Furthermore, the present invention relates to the composite in which the carbon nanofiber having a carboxyl group is a multilayer carbon nanotube having a carboxyl group, a single-walled carbon nanotube having a carboxyl group, or graphite having a carboxyl group.

Furthermore, the present invention relates to the composite in which the substrate is paper, thread, cloth or plastic film.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a composite composed of a carbon nanofiber having a carboxyl group, a cross-linking agent, and a base material, which has excellent conductivity, high storage stability, and high film strength after cross-linking. ..

Hereinafter, the present invention will be described in detail.

As a method for producing carbon nanofibers having a carboxyl group, in order to introduce a carboxyl group into the carbon nanofibers, heating with an acid having an oxidizing action may be sufficient. This operation is preferable because it is relatively easy and a highly reactive carboxyl group can be added. The operation will be briefly described.

Examples of the acid having an oxidizing action include concentrated nitric acid, hydrogen peroxide solution, a mixed solution of sulfuric acid and nitric acid, and aqua regia. In particular, when concentrated nitric acid is used, the concentration thereof is preferably 60% by mass or more.

The heating may be carried out by a conventional method, but the temperature is preferably equal to or lower than the boiling point of the acid used. For example, concentrated nitric acid is preferably in the range of 50 to 130 ° C. The heating time is preferably in the range of 30 minutes to 20 hours, more preferably in the range of 1 hour to 8 hours.

Carbon nanofibers (carbon nanofiber carboxylic acid) to which a carboxyl group is added are generated in the reaction solution after reflux, and the desired solution is cooled to room temperature and separated or washed as necessary. Carbon nanofibers having a carboxyl group can be obtained.

Examples of carbon particles derived from an inorganic carbon material used as carbon nanofibers include carbon black such as furnace black, acetylene black, ketjen black and medium thermal carbon black, activated carbon, graphite, carbon nanotubes, carbon nanohorns, graphene, and graphene. Examples thereof include nanoplatelets, nanoporous carbon and carbon fibers.

In the present invention, the graphene nanoplatelet has a multi-layer structure in which graphene sheets having a planar structure in which carbon atoms form a hexagon are weakly bonded by van der Waals force. Graphene nanoplatelets have a planar structure with few defects, so they exhibit high electron conductivity, high thermal conductivity, and high mechanical strength.

In the present invention, carbon black is fine carbon particles in which primary particles have a structure in which particles called structures are connected or aggregated, and have a large specific surface area and high electron conductivity.

In the present invention, carbon nanotubes include single-walled carbon nanotubes and multi-walled carbon nanotubes.

Single-walled carbon nanotubes have a seamless cylindrical shape with a diameter in the nanometer region, and can be imagined as a rounded graphene sheet (two-dimensional graphite plane). The structure of the nanotube is defined by the diameter and the relative orientation of the 6-membered ring of carbon with respect to the axis of the tube. For example, Meijo Nanocarbon (EC1.0, EC1.5, EC2.0, EC1.5-P) and the like can be mentioned. In addition, SG65i, SG65, SG76, CG100, CG200, CG300 and the like of Aldrich Co., Ltd. can be mentioned.

Multi-walled carbon nanotubes are composed of these concentric cylindrical tubes, and it is thought that several single-walled tubes are nested. .. Therefore, the diameter of the multi-walled carbon nanotube shows a large value of 30 nm with respect to 0.7 to 2.0 nm of a typical single-walled carbon nanotube. The excellent and unique properties of carbon nanotubes make it possible to develop new applications and improve performance in existing applications. For example, CNano (FloTube9000, FloTube9100, FloTube9110, FloTube9200), Nanocyl (NC7000), Knano (100T), Toyo Color Co., Ltd., JP-A-2016-13680, JP-A-2013-166140, JP-A-2014. Examples thereof include multi-walled carbon nanotubes described in JP-A-001083.

Examples of commercially available inorganic carbon particles include Ketjen Black EC-300J and Ketchen Black manufactured by Lion Specialty Chemicals Co., Ltd. such as EC-600JD;
Tokai Carbon Furnace Black such as Talker Black # 4300, # 4400, # 4500, and # 5500;
Degusa Furness Black such as Printex L;
Colombian Furnace Black such as Raven 7000, 5750, 5250, 5000 ULTRA III, 5000 ULTRA, Conductex SC ULTRA, 975 ULTRA, PUER BLACK 100, 115, 205;
Mitsubishi Chemical Furnace Black such as # 2350, # 2400B, # 2600B, # 3050B, # 3030B, # 3230B, # 3350B, # 3400B, and # 5400B;
Cabot Furnace Black such as MONARCH 1400, 1300, 900, Vulcan XC-72R, and Black Pearls 2000;
TIMCAL Furnace Black such as Ensaco250G, Ensaco260G, Ensaco350G, and SuperP-Li;
Denka Black, Denka Black HS-100, FX-35, etc. Denka acetylene black;
Showa Denko's carbon nanotubes such as VGCF, VGCF-H, and VGCF-X;
Graphene nanoplatelets manufactured by XGSciences such as xGnP-C-750 and xGnP-M-5;
Graphite manufactured by Ito Graphite Industry Co., Ltd. such as EC1500, EC1000, EC500, EC300, EC100, PC-H, PC-10, PC-30;
Examples thereof include, but are not limited to, carbon fibers manufactured by Gun Ei Chemical Industry Co., Ltd. such as Kainol carbon fiber and Kainol activated carbon fiber.

In the general formula (1) used as a cross-linking agent in the present invention, X is an n-valent aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic hydrocarbon group, aliphatic heterocyclic group, or It represents an aromatic heterocyclic group, where n is an integer of 2 to 6, and R ¹ and R ² are independently hydrogen atoms, a group represented by the general formula (2), an aliphatic hydrocarbon group, and the like. It represents an alicyclic hydrocarbon group or an aromatic hydrocarbon group ^{, and at least one of R 1} and R ² is a group represented by the general formula (2).

Examples of the linear aliphatic hydrocarbon group of X in the general formula (1) include an alkyl group, an alkenyl group, an alkynyl group, an alkadienyl group, and an alkatrienyl group. Further, n of the hydrogen atoms contained in the alkyl group, the alkenyl group, the alkynyl group, the alkadienyl group and the alkatrienyl group can be substituted.

Here, as the divalent or higher valent alkyl group, 1,6-hexyl group, 1,7-heptyl group, 1,8-octyl group, 1,9-nonyl group, 1,6-decyl group, 1,10 -Decil group, 1,11-Undecyl group, 1,12-Dodecyl group, 1,13-Tridecyl group, 1,14-Tetradecyl group, 1,15-Pentadecyl group, 1,16-Hexadecyl group, 1,17- Heptadecyl group, 1,18-octadecyl group, 1,19-nonadecil group, 1,20-icosyl group, 1,3,6-hexyl group, 1,4,7-heptyl group, 1,2,8-octyl group , 1,3,9-nonyl group, 1,3,4,6-hexyl group, 1,4,6,7-heptyl group, 1,4,5,6,7-heptyl group, 1,2,3 , 4,5,6-Hexyl group and other alkyl groups having 6 or more carbon atoms can be mentioned.

Examples of the divalent or higher alkenyl group include 1,6- (2-hexenyl) group, 1,7- (2-heptenyl) group, 1,8- (2-octenyl) group, and 1,9- (2). -Nonenyl) group, 1,10- (2-decenyl) group, 1,11- (2-undecenyl) group, 1,12- (2-dodecenyl) group, 1,13- (2-tridecenyl) group, 1 , 14- (2-tetradecenyl) group, 1,15- (2-pentadecenyl) group, 1,16- (2-hexadecenyl) group, 1,17- (2-heptadecenyl) group, 1,18- (2-) Octadesenyl) group, 1,19- (2-nonadesenyl) group, 1,3,6- (2-hexenyl) group, 1,4,7- (3-hepsenyl) group, 1,2,8- (4-) Octenyl) group, 1,3,9- (5-nonenyl) group, 1,3,4,6- (2-hexenyl) group, 1,4,6,7- (3-hepsenyl) group, 1,4 , 5, 6, 7- (3-hepsenyl) group, and alkenyl groups having 6 or more carbon atoms can be mentioned.

The divalent or higher alkynyl groups include 1,6- (2-hexynyl) group, 1,7- (2-hepsinyl) group, 1,8- (2-oxynyl) group, and 1,9- (2). -Nonyl) group, 1,10- (2-decynyl) group, 1,11- (2-undecynyl) group, 1,12- (2-dodecynyl) group, 1,13- (2-tridecynyl) group, 1 , 14- (2-tetradecynyl) group, 1,15- (2-pentadecynyl) group, 1,16- (2-hexadecynyl) group, 1,17- (2-heptadecynyl) group, 1,18- (2-) Octadesinyl group, 1,19- (2-nonadecinyl) group, 1,3,6- (2-hexynyl) group, 1,4,7- (3-hepsinyl) group, 1,2,8- (4-) Oxinyl) group, 1,3,9- (5-nonyl) group, 1,3,4,6- (2-hexynyl) group, 1,4,6,7- (3-hepsinyl) group, 1,4 , 5, 6, 7- (3-hepsinyl) group, and alkenyl groups having 6 or more carbon atoms can be mentioned.

Examples of the alicyclic hydrocarbon group in the general formula (1) include a cycloalkyl group, a decahydronaphthyl group, and an adamantyl group.

Examples of the divalent or higher alicyclic hydrocarbon group include 1,1-cyclohexyl group, 1,2-cyclohexyl group, 1,3-cyclohexyl group, 1,4-cyclohexyl group and 1,2,4-cyclohexyl group. Group, 1,3,5-cyclohexyl group, 1,2,4,5-cyclohexyl group, 1,2,3,4,5,6-cyclohexyl group, 2,6-decahydronaphthyl group, 1,3- Cycloalkyl groups having 6 or more carbon atoms such as an adamantyl group, 1,3,5-adamantyl group can be mentioned.

Examples of the divalent or higher valent aliphatic heterocyclic group include aliphatic heterocyclic groups having 3 to 18 carbon atoms such as 2-pyrazolino group, piperidino group, morpholino group and 2-morpholinyl group.

Examples of the divalent or higher valent aromatic hydrocarbon group include a monocyclic ring, a condensed ring, and a ring-assembled aromatic hydrocarbon group.

Here, as the monocyclic aromatic hydrocarbon group, a monocyclic aromatic group such as a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,4-xylyl group, a p-cumenyl group, or a mesityl group. Group hydrocarbon groups can be mentioned.

The fused ring aromatic hydrocarbon group includes 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthrill group, 5-anthrill group, 1-phenanthryl group, 9-phenanthryl group and 1-acenaphthyl. Examples thereof include a fused ring aromatic hydrocarbon group such as a group, a 2-azulenyl group, a 1-pyrenyl group and a 2-triphenylel group.

Examples of the ring-assembled aromatic hydrocarbon group include a ring-assembled aromatic hydrocarbon group such as an o-biphenylyl group, an m-biphenylyl group, and a p-biphenylyl group.

Examples of the divalent or higher aromatic heterocyclic group include a triazolyl group, a 3-oxadiazolyl group, a 2-furanyl group, a 3-furanyl group, a 2-furyl group, a 3-furyl group, a 2-thienyl group and a 3-thienyl group. Group, 1-pyro-lyl group, 2-pyro-lyl group, 3-pyro-lyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3- Isooxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group, 3-pyrazolyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7- Kinolyl group, 8-quinolyl group, 1-isoquinolyl group, 2-quinoxalinyl group, 2-benzofuryl group, 2-benzothienyl group, N-indrill group, N-carbazolyl group, N-acrydinyl group, 2-thiophenyl group, 3 Examples thereof include aromatic heterocyclic groups having 2 to 18 carbon atoms such as a thiophenyl group, a bipyridyl group and a phenanthrolyl group.

Further, in X in the general formula (1), it is preferably a linear aliphatic hydrocarbon group having 2 to 20 carbon atoms or an alicyclic hydrocarbon group, and more preferably 4 to 12 carbon atoms. Is a straight-chain aliphatic hydrocarbon group or an alicyclic hydrocarbon group, more preferably a straight-chain aliphatic hydrocarbon group having 6 to 12 carbon atoms.

^{Further, among R 1} and R ^{2 in} the general formula (1), examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group and an alkynyl group.

Here, as the alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a hexyl group, a heptyl group and an octyl group. , Decyl group, dodecyl group, pentadecyl group, octadecyl group and other alkyl groups.

The alkenyl group includes a vinyl group, a 1-propenyl group, a 2-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 1-octenyl group, a 1-decenyl group, and 1 -An alkenyl group such as an octadecenyl group can be mentioned.

Examples of the alkynyl group include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a 1-octynyl group, a 1-decynyl group and a 1-octadecynyl group. An alkynyl group can be mentioned.

Examples of the alicyclic hydrocarbon group in R ¹ and R ² in the general formula (1) include the cycloalkyl group described above in X in the general formula (1).

Examples of the cycloalkyl group include a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclooctadecyl group and a 2-indeno group.

^{Further, examples of the aromatic hydrocarbon group in R 1} and R ² in the general formula (1) include a monocyclic ring, a condensed ring, and a ring-aggregated aromatic hydrocarbon group.

Here, as the monocyclic aromatic hydrocarbon group, a monocyclic aromatic group such as a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 2,4-xylyl group, a p-cumenyl group, or a mesityl group. Group hydrocarbon groups can be mentioned.

The fused ring aromatic hydrocarbon group includes 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthrill group, 5-anthrill group, 1-phenanthryl group, 9-phenanthryl group and 1-acenaphthyl. Examples thereof include a fused ring aromatic hydrocarbon group such as a group, a 2-azulenyl group, a 1-pyrenyl group and a 2-triphenylel group.

Examples of the ring-assembled aromatic hydrocarbon group include a ring-assembled aromatic hydrocarbon group such as an o-biphenylyl group, an m-biphenylyl group, and a p-biphenylyl group.

^{Further, R 1} and R ² in the general formula (1) are preferably an aliphatic hydrocarbon group, an alicyclic hydrocarbon or a monocyclic aromatic hydrocarbon group, and more preferably an aliphatic hydrocarbon group. , An alicyclic hydrocarbon, more preferably an aliphatic hydrocarbon group having 4 or more carbon atoms.

^{Further, R 3 to} R ⁶ in the general formula (2) independently represent a hydrogen atom or an aliphatic hydrocarbon group.

Here, examples of the aliphatic hydrocarbon group include those described above in ^{R 1} and R ^{2 in the general formula (1).}

Representative examples of the compound represented by the general formula (1) used in the present invention are shown in Table 1 below, but the present invention is not limited to this representative example.

Table 1

The compound represented by the general formula (1) used for the cross-linking agent in the present invention amidates a divalent or higher carboxylic acid or a derivative thereof and a primary or secondary amine having one or more hydroxy groups at the β-position. The specific synthesis thereof was carried out according to a known method (Japanese Patent Laid-Open No. 2013-151639, etc.). The compound represented by the general formula (1) is soluble in water and an organic solvent.

Examples of the organic solvent here include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, and propyl acetate. Examples thereof include butyl acetate, benzene, toluene, ethylbenzene, xylene, cyclohexane, hexane, octane, cyclolomethane, chloroform, dimethylformamide, dimethylacetamide, acetonitrile, dimethylsulfoxide, and the like.

The epoxy group-containing compound used as the cross-linking agent in the present invention is not particularly limited as long as it is a compound containing an epoxy group in the molecule. For example, examples of the compound having one epoxy group in the molecule include compounds such as N-glycidyl phthalimide, glycidol, and glycidyl (meth) acrylate. These can be suitably used for the purpose of controlling the crosslink density of the cured product by using them in combination with a compound having two or more epoxy groups in the molecule exemplified below, if necessary. Examples of the compound containing two or more epoxy groups in the molecule include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, and the like. Bisphenol F / epichlorohydrin type epoxy resin, bisphenol S / epichlorohydrin type epoxy resin, bisphenol AD / epichlorohydrin type epoxy resin, biphenol / epichlorohydrin type epoxy resin, ethylene oxide adduct of bisphenol A or Epichlorohydrin type epoxy resin of propylene oxide adduct, polyglycidyl ether of glycerin / epichlorohydrin adduct, naphthalenediol diglycidyl ether, resorcinol diglycidyl ether, polybutadiene diglycidyl ether, hydroquinone diglycidyl ether, dibromoneopentyl Glycol diglycidyl ether, neopentyl glycol diglycidyl ether, hexahydrophthalic acid diglycidyl ester, hydrogenated bisphenol A type diglycidyl ether, polypropylene glycol diglycidyl ether, diphenylsulfone diglycidyl ether, dihydroxybenzophenone diglycidyl ether, biphenol diglycidyl Ether, diphenylmethane diglycidyl ether, bisphenol full orange glycidyl ether, biscresol full orange glycidyl ether, bisphenoxyethanol full orange glycidyl ether, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N-diglycidyl Aniline, N, N-diglycidyl toluidine, highly flexible epoxy compounds disclosed in JP-A-2004-156024, JP-A-2004-315595, and JP-A-2004-323777, and the following formulas ( Examples thereof include epoxy compounds having the structures represented by a) to (e).

Equation (a)

Equation (b)

Equation (c)

Equation (d)

Equation (e)

Furthermore, trishydroxyethyl isocyanurate triglycidyl ether, triglycidyl isocyanurate, "Epicoat 1031S", "Epicoat 1032H60", "Epicoat 604", "Epicoat 630" manufactured by Mitsubishi Chemical Corporation, phenol novolac type epoxy resin, cresol Novolak type epoxy resin, dicyclopentadiene type epoxy resin disclosed in Japanese Patent Application Laid-Open No. 2001-240654, naphthalene type epoxy resin, polyglycidyl ether of ethylene glycol / epichlorohydrin adduct, pentaerythritol polyglycidyl ether, trimethylpropanpoly Examples thereof include glycidyl ether, N, N, N', N'-tetraglycidyl-m-xylene diamine, and the like. Further, a compound having a thermosetting group other than the epoxy group can also be used. For example, silane-modified epoxy resins disclosed in JP-A-2001-59011 and JP-A-2003-48953 can be mentioned.

In particular, "Epicoat 1031S", "Epicoat 1032H60", "Epicoat 604", and "Epicoat 630" manufactured by Mitsubishi Chemical Corporation are preferable in the present invention because they are polyfunctional and have excellent heat resistance, and are aliphatic. The epoxy compounds of the system and the epoxy compounds described in JP-A-2004-156024, JP-A-2004-315595, and JP-A-2004-323777 are preferable because they are excellent in the flexibility of the crosslinked product. Further, the dicyclopentadiene type epoxy compound described in JP-A-2001-240654, the phenol novolac type epoxy resin, the cresol novolac type epoxy resin, the biphenol / epichlorohydrin type epoxy resin, and the bisphenol A type manufactured by Mitsubishi Chemical Co., Ltd. Basic liquid type grades "825", "828", "828EL", "828US", "828XA" which are epoxy compounds, and "EOCN-102O" and "EOCN-102O" which are cresol novolac type epoxy resins manufactured by Nippon Kayaku Co., Ltd. EOCN-102S ”,“ EOCN-103S ”, and phenol novolac type epoxy resins“ EPPN-201 ”,“ EPPN-201L ”,“ EPPN-502H ”, etc. are heat-curable and hygroscopic in the present invention. It is preferable because it is excellent in terms of durability of the crosslinked product including heat resistance.

In the present invention, only one type of cross-linking agent may be used alone, or a plurality of cross-linking agents may be used in combination. The amount of the cross-linking agent used may be determined in consideration of the use of the composite of the present invention and the like, and is not particularly limited, but is 0.1 with respect to 100 parts by mass of the carbon nanofiber having a carboxyl group. It is preferably added at a ratio of ~ 100 parts by mass, and more preferably 0.1 to 10 parts by mass. By using a cross-linking agent, carbon nanofibers having a carboxyl group can be cross-linked, so that the strength of the composite after cross-linking can be increased even in a small amount.

An example of obtaining the complex of the present invention will be described. At least, a crosslink which is at least one selected from the group consisting of carbon nanofibers having a carboxyl group, a compound represented by the following general formula (1), an epoxy group-containing compound, an isocyanate group-containing compound and a blocked isocyanate group-containing compound. Examples thereof include a method in which a composition composed of an agent and a solvent is prepared, the composition is applied to various substrates, the solvent is evaporated and dried, and cross-linking is allowed to proceed by heating or the like.

Examples of solvents that can be used in the composition include water and the following various solvents.
Alcohols: methanol, ethanol, propanol, isopropanol and the like.
Ketones: Acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.
Carbonic acid esters: propylene carbonate, ethylene carbonate, vinylene carbonate, methylpropyl carbonate and the like.
Esters: Ethyl propionate, γ-butyrolactone, γ-valerolactone, δ-valerolactone, methyl acetate, and ethyl acetate.
Ethers: Ethylene glycol dimethyl ether, ethylene glycol diethyl ether, glycol ether and the like.
Sulfoxides: Dimethyl sulfoxide, etc.

The composition further comprises a non-reactive resin, a thermosetting resin, a photocurable resin, a curing agent used in combination, a photoinitiator, a sensitizer, a leveling agent, an ultraviolet absorber, a light stabilizer, as required. Additives such as antioxidants, inorganic fillers, adhesion enhancers, etc. may be added.

The coating method of the composition includes spin coating method, spray method, roller coating method, gravure coating method, die coating method, comma coating method, roll coating method, curtain coating method, bar coating method, inkjet method, dispenser method, and silk. Examples thereof include methods using various means such as screen printing and flexographic printing. It can be appropriately selected from the above methods according to the thickness to be coated, the viscosity of the composition and the like.

It is also possible to impregnate the composition with a base material and apply it. When the base material is a thread or cloth, it is the most effective means to apply the composition to the surface of the base material by this method. Is.

The thickness of the film obtained by coating the composition is not particularly limited, but it is preferably formed so as to have a certain thickness or more.

The desired composite is obtained by applying the composition to one or both sides of various substrates, molding using a mold or the like, drying by heating if necessary, and then heat-polymerizing at 100 to 200 ° C. Can be done.

Examples of the base material include various metals such as paper, thread, cloth, glass, plastic film, and stainless steel, and examples of paper include Japanese paper made of vegetable fibers, Western paper made of pulp, and synthetic paper made of plastic fibers. And so on. Next, examples of the thread include those made of vegetable fibers, those made of animal fibers, those made of plastic fibers, and the like. Next, examples of the cloth include cloths such as cotton made of vegetable fibers, cloths such as wool made of animal fibers, and chemical fibers made of plastic fibers. Next, examples of glass include glass fiber and glass plate. Next, examples of the plastic film include polycarbonate, polyester, urethane, acrylic, polyacetate cellulose, polyamide, polyimide, polystyrene, epoxy resin, polyolefin, polycycloolefin, polyvinyl alcohol and the like. Next, examples of various metals include wire-shaped metals such as copper wires, plate-shaped metals such as aluminum plates, and fibrous metals.

The temperature at which the dried product of the composition is crosslinked is preferably 100 to 180 ° C. At this time, when the mass of half or more of the entire cross-linking agent is the compound of the general formula (1), the cross-linking reaction can be carried out at a low temperature. In this case, it is possible to use a base material that cannot withstand a high temperature of 150 ° C. or higher, and the temperature at which the dried product of the composition is crosslinked is preferably 100 to 140 ° C.

By further adding a photoacid generator to the composition, cross-linking with ultraviolet rays can also be performed.

The composite of the present invention not only prevents the carbon nanofibers from falling off due to rubbing or abrasion by cross-linking between the carbon nanofibers and the cross-linking agent, but is also excellent in heat cycle property and bendability due to its toughness. It is expected that a conductive composite having excellent durability and flexibility can be provided.

The carbon nanofiber having a carboxyl group used in the present invention is a carbon particle derived from an inorganic carbon material in which a carboxyl group is bonded to the terminal and / or side surface of the carbon material. For example, carbon particles derived from an inorganic carbon material having a carboxyl group include carbon black such as furnace black, acetylene black, ketjen black and medium thermal carbon black, activated carbon, graphite, single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanohorns. , Graphene nanoplatelets, nanoporous carbon, carbon fibers and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. Unless otherwise specified, "%" means "mass%" and "part" means "parts by mass".

All NMR measurements in the examples, the the ¹ H-NMR measurement using a JEOL Co. JNM-ECX400P were performed in DMSO-d6.

All IR measurements in the examples were performed using a Spectrum One manufactured by PerkinElmer.

Hereinafter, a method for producing multi-walled carbon nanotubes manufactured by Toyo Color Co., Ltd. will be shown.
(Manufacturing Example 1) [Manufacturing of catalyst for synthesizing carbon nanotubes]
Weigh 200 parts of cobalt acetate / tetrahydrate, 172 parts of magnesium acetate / tetrahydrate, and 3.5 parts of hexaammonium heptamolybdate / tetrahydrate in a beaker, and add 1488 parts of purified water to completely dissolve. Stirred until Transfer to a heat-resistant container, dry in an electric oven at an ambient temperature of 150 ± 5 ° C. for 60 minutes to evaporate the water content, and then grind in a mortar to obtain a catalyst precursor having an average particle size (D50) of 20 μm. Obtained. 300 parts of the obtained catalyst precursor is weighed in a heat-resistant container, fired in a muffle furnace in an atmosphere of 450 ± 5 ° C. for 60 minutes, and then pulverized in a mortar to obtain a catalyst having an average particle size (D50) of 2 μm. Obtained.

(Manufacturing Example 2) [Manufacturing of multilayer carbon nanotubes]
A quartz glass heat-resistant dish sprayed with 1.0 g of the catalyst obtained in Production Example 1 was installed in the central portion of a horizontal reaction tube that can be depressurized and can be heated by an external heater. After depressurizing the air in the horizontal reaction tube to 1 × 10 ³ Pa with a vacuum pump, inject argon gas to 8 × 10 ^{4 Pa, and depressurize again to 1 × 10 3} Pa with a vacuum pump, and this process is repeated twice. The oxygen concentration in the horizontal reaction tube was set to 0.1% by volume or less. It was heated by an external heater while maintaining 1 × 10 ³ Pa, and the central part of the horizontal reaction tube was heated to 850 ° C. Maintaining the synthesis temperature 850 ± 5 ° C., poured butane / propane mixed gas, to produce a multi-walled carbon nanotubes 3 hours and reacted while maintaining the pressure in the reaction tube to ^{3 × 10 4 Pa~6 × 10 4} Pa. After completion of the synthesis, the gas in the reaction tube was replaced with argon gas and taken out at a temperature of 200 ° C. or lower to obtain multi-walled carbon nanotubes.

Hereinafter, the carbon nanofiber having a carboxyl group in the synthesis example was synthesized by the following method.

Synthesis of carbon nanofibers (1) having a carboxyl group In a reaction vessel equipped with a stirrer, a thermometer, and a dropping device, 200 parts of 60% nitric acid, 800 parts of concentrated sulfuric acid, and 25 parts of multi-walled carbon nanotubes manufactured by Toyo Color Co., Ltd. are placed in 60 parts. The mixture was heated and stirred at ° C. for 8 hours. Then, it cooled to room temperature and put into 10 L ice water. The precipitated multi-walled carbon nanotubes were separated by suction and filtered, and further washed with 20 L of ion-exchanged water to obtain carbon nanofibers (1) having 19 parts of carboxyl groups.

Synthesis of carbon nanofibers (2) having a carboxyl group In a reaction vessel equipped with a stirrer, a thermometer, and a dropping device, 100 parts of 60% nitric acid, 400 parts of concentrated sulfuric acid, and 10 parts of Aldrich single-walled carbon nanotubes (CG100) were placed. The mixture was added and heated and stirred at 60 ° C. for 8 hours. Then, it was cooled to room temperature and put into 5 L of ice water. The precipitated single-walled carbon nanotubes were separated by suction and filtration, and further washed with 10 L of ion-exchanged water to obtain carbon nanofibers (2) having 8 parts of carboxyl groups.

Synthesis of carbon nanofibers (3) having a carboxyl group In a reaction vessel equipped with a stirrer, a thermometer, and a dropping device, 100 parts of 60% nitric acid, 400 parts of concentrated sulfuric acid, and 5 parts of Ketjen Black (EC-600JD) were placed. The mixture was stirred at 30 ° C. for 30 minutes. Then, it was put into 5 L of ice water. The precipitated Ketjen black was separated by suction and filtration, and further washed with 10 L of ion-exchanged water to obtain carbon nanofibers (3) having three portions of carboxyl groups.

Synthesis of carbon nanofibers (4) having a carboxyl group Put 100 parts of 60% nitric acid, 400 parts of concentrated sulfuric acid, and 5 parts of graphite (EC1500) in a reaction vessel equipped with a stirrer, a thermometer, and a dropping device, and 8 at 80 ° C. The mixture was heated and stirred for hours. Then, it was cooled to room temperature and put into 5 L of ice water. The precipitated graphite was separated by suction and filtration, and further washed with 10 L of ion-exchanged water to obtain carbon nanofibers (4) having 5 parts of carboxyl groups.

Hereinafter, an example of synthesizing the compound represented by the general formula (1) will be shown. The compound numbers indicate the compound numbers in Table 1.

Synthesis Example 1 Synthesis of compound (1) In a reaction vessel equipped with a stirrer, a thermometer, a dropping device, a Dean-Stark tube, a reflux condenser, and a gas introduction tube, 225 parts of dimethyl sverate (dimethyl octaneate) and 234 parts of diethanolamine. , 10 parts of potassium hydroxide and 300 parts of toluene were added, the Dean-Stark apparatus was filled with toluene, and the mixture was heated under reflux while blowing nitrogen to remove water generated by azeotrope. After 4 hours, all toluene was removed, and ¹ H-NMR measurement and IR measurement were performed to confirm that the desired product was produced. After lowering the temperature to 50 ° C., the obtained uniform pale yellow transparent solution was taken out.

Synthesis Example 2 Synthesis of compound (2) In a reaction vessel equipped with a stirrer, a thermometer, a Dean-Stark tube, a reflux condenser, and a decompression device under a nitrogen atmosphere, 1,000 mmol (216. 27 g), 2,000 mmol (210.28 g) of diethanolamine, and 50 mmol (3.40 g) of sodium ethoxide were added, and the mixture was heated and stirred under normal pressure until the internal temperature reached 90 ° C. When the internal temperature reached 90 ° C., the pressure was reduced to 500 hPa, and the mixture was heated and stirred at 100 ° C. for 2 hours to allow the reaction to proceed while distilling off the methanol produced. After 2 hours, the mixture was heated and stirred for another 1 hour under a reduced pressure of 200 hPa to distill off all the remaining methanol. ¹ It was confirmed that the target product was produced by performing 1 H-NMR measurement and IR measurement. After lowering the temperature to 50 ° C., the obtained uniform pale yellow transparent solution was taken out.

Synthesis Example 3 Synthesis of compound (3) 1,000 mmol (230. dimethyl decanoate) of dimethyl sebacate (dimethyl decanoate) in a reaction vessel equipped with a stirrer, a thermometer, a Dean-Stark tube, a reflux condenser, and a decompression device under a nitrogen atmosphere. 30 g), 2,000 mmol (210.28 g) of diethanolamine, and 50 mmol (6.46 g) of diisopropylethylamine were added, and the mixture was heated and stirred under normal pressure until the internal temperature reached 90 ° C. When the internal temperature reached 90 ° C., the mixture was heated and stirred under a reduced pressure of 500 hPa for 2 hours, and the reaction was allowed to proceed while distilling off the produced methanol. After 2 hours, the mixture was heated and stirred for another 1 hour under a reduced pressure of 200 hPa to distill off all the remaining methanol. ¹ It was confirmed that the target product was produced by performing 1 H-NMR measurement and IR measurement. After lowering the temperature to 50 ° C., the obtained uniform pale yellow transparent solution was taken out.

Compounds (4) to (51) were also synthesized by the same procedure as in the above synthesis example.

Example 1
A composite composed of carbon nanofibers having a carboxyl group, the compounds shown in Table 1, and a base material was prepared as follows, and a conductivity test, a curing test, and a cured film strength test were performed.

As shown in Table 2, the carbon nanofibers (1) having a carboxyl group, the compound (1) in Table 1 as a cross-linking agent, and water are adjusted so that the mass ratio is 5: 0.5: 94.5. Then, it was dispersed with Scandex for 60 minutes to prepare a crosslinkable composition.

Regarding the obtained crosslinkable composition, the agglomerates were visually confirmed, and the results were shown in Table 2 as 〇 if there was no agglutinin, Δ if there was a slight amount, and × if there was clearly.

The obtained crosslinkable composition is applied to the PET film which is the base material of Table 2 with a bar coater which is the coating method shown in Table 2, and after evaporating the water content, the temperature is 120 ° C., 150 ° C., 180 ° C. The coating film was crosslinked in each of the ovens for 10 minutes to obtain a composite. The crosslinked coating film was subjected to a redissolution test in water. Regarding the results, Table 2 shows that insoluble is 〇 and dissolved is ×.

The conductivity of the coating film heated at 120 ° C. for 10 minutes was measured using a Loresta GX MCP-T700 manufactured by Mitsubishi Chemical Analytech Co., Ltd. after measuring the film thickness separately. The results are shown in Table 2 with conductivity as 〇 and non-conductive as ×.

Examples 2-60
A composite was prepared and tested in the same manner as in Example 1 except that carbon nanofibers having a carboxyl group and the materials shown in Table 2 were used as the cross-linking agent. The results are shown in Table 2.

The description of the cross-linking agent in Table 2 shall be as follows.
828: Mitsubishi Chemical Co., Ltd., bisphenol A type epoxy compound EOCN-102S: Nippon Kayaku Co., Ltd., cresol novolac type epoxy resin EPPN-201L: Nihon Kayaku Co., Ltd., phenol novolac type epoxy resin PVDF: polyvinylidene fluoride

Comparative Examples 1-5
A composite was prepared and tested in the same manner as in Example 1 except that the materials shown in Table 2 were used as carbon nanofibers having no carboxyl group or resins having no crosslinkability. However, even if a cross-linking reaction could not be expected, a uniform study was conducted. The results are shown in Table 2.

The redissolution tests of Examples 52 to 60 at 120 ° C. oven heating showed poor curing, but it was confirmed that Examples 1 to 51 were good in all other tests.

Comparative Examples 1 to 4 are examples in which multi-walled carbon nanotubes, single-walled carbon nanotubes, Ketjen black and graphite are used as carbon nanofibers having no carboxyl group, but the dispersibility in a solvent is poor and a large amount of aggregates are present. The coating film was discontinuous and the strength of the film was not sufficient. It is considered that the conductive performance was not exhibited because the film was discontinuous.

Comparative Example 5 is an example in which only a non-crosslinkable resin is added to carbon nanofibers having a carboxyl group, but since the carbon nanofibers having a carboxyl group have excellent dispersibility, a continuous coating film is formed. However, the film strength was not sufficient because there was no cross-linking reaction, and the conductivity performance was also low because the interaction between the materials was weak.

From the above, the complex which is a crosslinked product of carbon nanofiber having a carboxyl group and at least one crosslinking agent selected from the group consisting of the compound represented by the general formula (1) and the epoxy group-containing compound is , It became clear that the conductivity performance is excellent.

The composite of the present invention can be used in various fields as conductive paper, thread, cloth, and plastic film.

Claims (3)

And carbon emissions having a carboxyl group, applying a composition comprising a crosslinking agent is a compound represented by the following general formula (1) to a substrate, impregnated or printed comprising complex.
General formula (1)

(In the formula, X represents an n-valent aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, an aliphatic heterocyclic group or an aromatic heterocyclic group, and n is an integer of 2 to 6. And
R ¹ and R ² independently represent a hydrogen atom, a group represented by the general formula (2), an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and R ¹ and R 2 respectively. of the ^two, at least one is a group represented by the general formula (2). )
General formula (2)

(In the formula, R ^{3 to} R ⁶ independently represent a hydrogen atom or an aliphatic hydrocarbon group.) Carbon emissions having a carboxyl group, a complex according to claim 1, wherein the graphite has a single-walled carbon nanotubes or a carboxyl group with multi-walled carbon nanotubes, the carboxyl group having a carboxyl group. The composite according to claim 1 or 2, wherein the base material is paper, thread, cloth or a plastic film.