JP5269353B2 - Carbon nanotube-containing structures and composites - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure containing carbon nanotubes and sufficiently exhibiting conductivity imparting effect of carbon nanotube and to provide a composite material produced by using the structure. <P>SOLUTION: The structure containing carbon nanotubes comprises (a) carbon nanotubes and (b) a resin, and satisfies the requirements that the average of the carbon nanotube areal ratio [A1] defined by formula (I) is &ge;10% and the average of the areal ratio [A2] of the fine aggregate of carbon nanotubes defined by formula (II) is &ge;25%. Formula (I): areal ratio of carbon nanotube [A1]=[(total occupied carbon nanotube area in the observation area)/(total observation area)]&times;100 (%), formula (II): areal ratio of fine aggregate of carbon nanotube [A2]=[(sum of the area of fine aggregate of carbon nanotube having a length of &ge;30 &mu;m)/(total occupied carbon nanotube area in the observation area)]&times;100 (%). <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a carbon nanotube-containing structure and an observation method thereof. The present invention also relates to a composite having a carbon nanotube-containing structure.

In recent years, nanotechnology that handles so-called nanomaterials having a nanometer size has attracted attention in various industrial fields. By combining nanomaterials with other materials at the nanometer level, new materials with new and superior functions have been developed.
By the way, since nanomaterials exhibit properties different from the bulk state by being highly dispersed, a technique for dispersing them in a composite is required. However, in general, since the surface state of nanomaterials is unstable, there is a problem that the nanomaterials are likely to aggregate at the time of compounding, and the functions specific to nanomaterials cannot be exhibited.

  Among the nanomaterials, carbon nanotubes have been evaluated for physical properties and functions have been elucidated since they were discovered in 1991, and research and development relating to their applications have been actively conducted. However, since carbon nanotubes are manufactured in an entangled state, there is a problem that when they are combined with a resin or a solution, they aggregate and cannot exhibit their original characteristics. For this reason, attempts have been made to uniformly disperse or dissolve carbon nanotubes in a solvent or resin by physically treating or chemically modifying carbon nanotubes. For example, Patent Document 1 proposes a composition comprising a carbon nanotube, a conductive polymer, a solvent, and a composite produced therefrom. Patent Document 2 proposes a composition comprising a nanomaterial, a (meth) acrylic polymer, a solvent, and a composite produced therefrom.

  The composites prepared from the compositions described in Patent Documents 1 and 2 exhibit conductivity by carbon nanotubes. However, since the dispersion state of the carbon nanotubes in the composite has not been quantified, it was unclear whether the dispersion state was such that the almost maximum conductivity possible with the carbon nanotube content could be expressed. . Further, the relationship between the dispersion state of carbon nanotubes and the conductivity was unknown. For this reason, there is a problem that it is difficult to obtain a complex capable of expressing almost the maximum conductivity possible even with a small amount of carbon nanotubes. That is, the conductivity imparting effect by the carbon nanotubes was not sufficiently exhibited.

Therefore, a carbon fiber-containing molded body in which an ultrafine carbon fiber is dispersed in a thermoplastic resin and having an area ratio [Ar] of 0.2 to 5.0% has been proposed (Patent Literature). 3). Here, the area ratio [Ar] is 1.23 × 10 ⁻¹ μm ² or more occupying a photograph of a slice of a resin molded body having a thickness of 1 μm at a magnification of 30 × with a transmission stereomicroscope. 0.0 × 10 ¹ μm ² or less particles are extracted, and the total area of the particles in the field of view is expressed as a percentage.
In this detection method, the single monodispersed carbon nanotube is below the lower limit of detection, and it cannot be said that the dispersion state of the entire coating film is grasped. Further, particles of 5.0 × 10 ¹ μm ² or more are also excluded and do not include a conductive network formed by fine aggregation of monodispersed carbon nanotubes. Therefore, the carbon fiber-containing molded article described in Patent Document 3 is not always highly conductive.

Moreover, it consists of carbon fiber and resin having an average fiber diameter of 50 to 500 nm and an average aspect ratio of 50 to 1000, and the volume ratio of the carbon fiber aggregate in the resin to one carbon fiber constituting the carbon fiber aggregate is 1500 or less. A conductive resin molded body has been proposed (see Patent Document 4).
However, Patent Document 4 describes that the smaller the volume ratio between the aggregate and the carbon fiber, the more uniformly dispersed and preferable, but there is no description regarding the conductive network formed by the fine aggregation of the carbon fiber.
Therefore, even in the resin molded bodies described in Patent Documents 3 and 4, the relationship between the dispersion state of the carbon nanotubes and the conductivity is not clear, and the conductivity imparting effect by the carbon nanotubes is not sufficiently exhibited.
Pamphlet of International Publication WO2004 / 039893 Pamphlet of International Publication WO2006 / 028200 JP 2006-193649 A JP 2006-11870 A

An object of the present invention is to provide a carbon nanotube-containing structure and composite that can sufficiently exhibit the conductivity imparting effect of the carbon nanotube.
Another object of the present invention is to provide a method for observing a carbon nanotube-containing structure capable of quantifying the dispersion state of carbon nanotubes in the carbon nanotube-containing structure and clarifying the relationship between the dispersion state and conductivity. .

The present invention includes the following aspects.
[1] A carbon nanotube-containing structure containing a carbon nanotube (a) and a resin (b),
The resin (b) comprises a polymer having a urethane (meth) acrylate compound unit,
The average value of the carbon nanotube area ratio [A1] represented by the following formula (I) is 10% or more, and the average value of the carbon nanotube fine aggregate area ratio [A2] represented by the following formula (II) is 25. %, A carbon nanotube-containing structure characterized by being at least%.
Formula (I): Carbon nanotube area ratio [A1] = [(total occupied area of carbon nanotubes in observation area) / (total observation area)] × 100 (%)
Formula (II): Carbon nanotube fine aggregate area ratio [A2] = [(total area of carbon nanotube fine aggregates having a length of 30 μm or more) / (occupied area of all carbon nanotubes in the observed image)] × 100 ( %)
However, the total occupied area of the carbon nanotubes in the observation area, the total area of the carbon nanotube fine aggregates having a length of 30 μm or more, and the occupied area of all the carbon nanotubes in the observation image are provided with an immersion lens and a confocal optical system. Using the confocal mode of the microscope, the carbon nanotube-containing structure is observed at predetermined intervals in the thickness direction, slice images are obtained, and an extended focus image reconstructed from the slice images is analyzed and obtained. Value. Moreover, area ratio [A1] and area ratio [A2] are calculated | required in three or more places, and the average value of area ratio [A1] is an average value of area ratio [A1] measured in three or more places, and area ratio [ The average value of A2] is the average value of the area ratio [A2] measured at three or more locations.
[2] The carbon nanotube-containing structure according to [1], which is a film.
[3] The carbon nanotube-containing structure according to [2], in which 45% by area or more of the carbon nanotubes (a) is contained in any part when divided into three equal parts in the thickness direction.
[4] A composite having the carbon nanotube-containing structure according to [2] or [3] on one side or both sides of a substrate.
[5] The composite according to [4], which is a transparent conductive film or a transparent conductive sheet .

The carbon nanotube-containing structure and composite of the present invention can sufficiently exhibit the conductivity imparting effect of the carbon nanotube.
According to the method for observing a carbon nanotube-containing structure of the present invention, the dispersion state of the carbon nanotube in the carbon nanotube-containing structure can be quantified, and the relationship between the dispersion state and conductivity can be clarified.

(Carbon nanotube-containing structure)
The carbon nanotube-containing structure of the present invention contains a carbon nanotube (a) and a resin (b).

<Carbon nanotube (a)>
The carbon nanotube (a) is a tube having an outer diameter of the order of nm formed by stacking 2 to several tens of layers of graphitic carbon.
Examples of the carbon nanotube (a) include ordinary carbon nanotubes, that is, single-walled carbon nanotubes, multi-walled carbon nanotubes in which single-walled carbon nanotubes are concentrically stacked in a multilayer shape, and those in a coil shape.
Further, the carbon nanotube (a) includes a carbon nanohorn having a closed shape on one side of the carbon nanotube, a cup-shaped nanocarbon material having a hole in the head thereof, a fullerene that is an analog of the carbon nanotube (a), Carbon nanofibers are also included.
Among these, single-walled carbon nanotubes and multi-walled carbon nanotubes are preferable in terms of higher conductivity.

  The carbon nanotube (a) can be produced by, for example, catalytic hydrogen reduction of carbon dioxide, arc discharge method, laser evaporation method, chemical vapor deposition method (CVD method), vapor phase growth method, high temperature and high pressure carbon monoxide. And HiPco method of growing in a gas phase by reacting with an iron catalyst. Moreover, when manufacturing a carbon nanotube (a), it is preferable to highly purify by various purification methods, such as a washing | cleaning method, a centrifugation method, a filtration method, an oxidation method, and a chromatographic method.

  The carbon nanotube (a) may be pulverized by a ball-type kneading apparatus such as a ball mill, a vibration mill, a sand mill, or a roll mill. The carbon nanotube (a) may be cut short by chemical and physical treatment.

<Resin (b)>
As the resin (b), both a thermosetting resin and a thermoplastic resin can be used.
Examples of the thermosetting resin include urea resin, melamine resin, xylene resin, phenol resin, unsaturated polyester, epoxy resin, furan resin, polybutadiene, polyurethane, melamine phenol resin, silicon resin, polyamideimide, and silicone resin. It is done.

  Examples of the thermoplastic resin include polyethylene, ethylene vinyl acetate copolymer resin, polypropylene, polystyrene, AS resin, ABS resin, methacrylic resin, polyvinyl chloride, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, cellulose acetate, diallyl phthalate. , Polyvinyl butyral, polyvinyl formal, polyvinyl alcohol, vinyl acetate resin, ionomer, chlorinated polyether, ethylene-α-olefin copolymer, ethylene vinyl acetate copolymer, chlorinated polyethylene, vinyl chloride vinyl acetate copolymer, chloride Vinylidene, acrylic vinyl chloride copolymer resin, AAS resin, ACS resin, polyacetal, polymethylene pentene, polyphenylene oxide, modified PPO, polyphenol Rene sulfide, butadiene styrene resin, thermoplastic polyurethane, polyamino bismaleimide, polysulfone, polybutylene, silicon resin, MBS resin, methacryl-styrene copolymer resin, polyamideimide, polyimide, polyetherimide, polyarylate, polyallylsulfone, polybutadiene , Polycarbonate methacrylate composite resin, polyether sulfone, polyether ether ketone, polyphthalamide, polymethylpentene, tetrafluoroethylene resin, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer Polymer, tetrafluoroethylene / ethylene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, chloroto Examples include trifluoroethylene / ethylene copolymer, polyvinyl fluoride, and liquid crystal polymer.

  Among the resins (b), a resin containing an acrylic resin or a methacrylic resin as a main component is preferably used from the viewpoints of the dispersibility of the carbon nanotubes and the conductivity and transparency of the resulting carbon nanotube-containing structure. Here, “including as a main component” means that acrylic resin and methacrylic resin in all resin components are 50% by mass or more.

Moreover, a conductive polymer can also be used as the resin (b). The conductive polymer is a π-conjugated polymer containing phenylene vinylene, vinylene, thienylene, pyrrolylene, phenylene, iminophenylene, isothianaphthene, furylene, carbazolylene or the like as a repeating unit.
In the present invention, a water-soluble conductive polymer is preferably used. A water-soluble conductive polymer is a conductive material having an acidic group, an alkyl group substituted with an acidic group, or an alkyl group containing an ether bond on the skeleton of a π-conjugated polymer or a nitrogen atom in the polymer. Polymer. Among these, a water-soluble conductive polymer having a sulfonic acid and / or a carboxy group is preferably used from the viewpoint of dispersibility of carbon nanotubes and conductivity of the structure.
Furthermore, polyethylenedioxythiophene polystyrene sulfate is also used as the conductive polymer. This water-soluble conductive polymer has a structure in which polystyrene sulfonic acid is added as a dopant, although no sulfonic acid group is introduced into the skeleton of the conductive polymer.

  The amount of the carbon nanotube (a) in the carbon nanotube-containing structure is preferably 0.001 to 20 parts by mass, and 0.01 to 10 parts by mass with respect to 100 parts by mass of the resin (b). More preferred. If the content of the carbon nanotube is 0.001 part by mass or more, the conductivity is sufficiently high, but even if the content exceeds 20 parts by mass, further improvement in conductivity cannot be expected.

In the carbon nanotube-containing structure of the present invention, a silane coupling agent, colloidal silica, a plasticizer, a coating surface adjusting agent, a fluidity adjusting agent, an ultraviolet absorber, an antioxidant, a storage stabilizer, an adhesive, if necessary. Auxiliaries, thickeners and the like may be included.
Further, the carbon nanotube-containing structure of the present invention can contain a conductive substance in order to further improve the conductivity. Examples of the conductive material include carbon-based materials such as carbon fiber, conductive carbon black, and graphite, metal oxides such as tin oxide and zinc oxide, metals such as silver, nickel, and copper, and symmetric or asymmetric type indoles. Derivative trimers and the like can be mentioned. Among these conductive materials, indole derivative trimers or their doped products are preferable.

<Dispersion state of carbon nanotube>
The carbon nanotube-containing structure of the present invention has a carbon nanotube area ratio [A1] represented by the following formula (I) of 10% or more and a carbon nanotube fine aggregate represented by the following formula (II): The average value of the area ratio [A2] is 25% or more. Preferably, the average value of the carbon nanotube area ratio [A1] represented by the following formula (I) is 15% or more, and the carbon nanotube fine aggregate area ratio [A2] represented by the following formula (II) Is an average value of 35% or more.

Formula (I): Carbon nanotube area ratio [A1] = [(total occupied area of carbon nanotubes in observation area) / (total observation area)] × 100 (%)
Formula (II): Carbon nanotube fine aggregate area ratio [A2] = [(total area of carbon nanotube fine aggregates having a length of 30 μm or more) / (occupied area of all carbon nanotubes in the observed image)] × 100 ( %)

Here, the “occupied area of all carbon nanotubes in the observation area” is the sum of the areas of monodispersed carbon nanotubes and fine aggregates formed by the carbon nanotubes extracted during binarization processing in image processing described later. is there.
The “total observation area” is an observation area with a microscope, and is, for example, 10,000 μm ² when observed at 1000 times.
“The total area of carbon nanotube fine aggregates having a length of 30 μm or more” is, among the fine aggregates formed by monodispersed carbon nanotubes and carbon nanotubes extracted during binarization processing in image processing described later, This is the total area of carbon nanotube fine aggregates having a maximum length of 30 μm or more.
A carbon nanotube fine aggregate is a carbon nanotube aggregate formed by at least one or more monodispersed carbon nanotubes contacting at least a part or more. Therefore, it is different from carbon nanotubes that are entangled without being dispersed. Since the carbon nanotube fine aggregate in the present invention is a part contributing to the formation of a conductive network in the carbon nanotube-containing structure, the correlation between the area ratio [A2] and the conductivity of the carbon nanotube-containing structure is large.

  In the carbon nanotube-containing structure, the average value of the area ratio [A1] and the average value of the area ratio [A2] are within the above ranges. This means that the carbon nanotubes in the structure can efficiently conduct the conductive network due to fine aggregation. It shows that it has formed. Therefore, the conductivity imparting effect by the carbon nanotubes can be sufficiently exhibited, and sufficient conductivity can be obtained even with a small content of carbon nanotubes, so that both transparency and conductivity can be easily achieved.

  In addition, from the viewpoint of transparency of the obtained carbon nanotube-containing structure, the average value of the area ratio [A1] is preferably 60%, more preferably 40% or less, and the average of the area ratio [A2]. The value is preferably 99% or less, and more preferably 95% or less.

<Observation method, observation conditions>
The total area of all the carbon nanotubes in the observation area, the total area of the carbon nanotube fine aggregates having a length of 30 μm or more, and the area occupied by all the carbon nanotubes in the observation image are a microscope having an immersion lens and having a confocal optical system. Using the confocal mode, a value obtained by observing the carbon nanotube-containing structure at predetermined intervals in the thickness direction to obtain slice images, and analyzing an extended focus image reconstructed from the slice images It is.
Moreover, area ratio [A1] and area ratio [A2] are calculated | required in three or more places, and the average value of area ratio [A1] is an average value of area ratio [A1] measured in three or more places, and area ratio [ The average value of A2] is the average value of the area ratio [A2] measured at three or more locations.

The immersion lens used in the microscope in the present invention is a lens filled with a liquid for adjusting the refractive index (hereinafter referred to as a refractive index adjusting liquid) between the observation sample and the objective lens. In the present invention, either a water immersion lens or an oil immersion lens can be used, but an oil immersion lens is preferred. By using an oil immersion lens, not only can a large numerical aperture be obtained and observation can be performed with high resolution, but also the influence of resin surface reflection can be reduced, and carbon nanotubes existing inside the carbon nanotube-containing structure surface can be observed with high resolution. Can be observed.
The refractive index adjusting liquid is not particularly limited as long as it does not damage the lens and the carbon nanotube-containing structure, but it is preferable to use a refractive index adjusting liquid having a refractive index close to the refractive index of the carbon nanotube-containing structure. For example, when the resin (b) is an acrylic resin, a commercially available refractive index adjusting liquid for immersion objective lens having a refractive index of about 1.518 is preferably used.

The confocal optical microscope used in the present invention is not particularly limited, but a confocal laser microscope is preferably used. By using a confocal laser microscope, not only the carbon nanotube distribution in the three-dimensional direction, but also the carbon nanotubes and carbon nanotubes present in a specific region of the carbon nanotube-containing structure, without pretreatment of the carbon nanotube-containing structure. It is possible to measure the formed fine aggregation area.
Although the wavelength of the laser used with a confocal laser microscope will not be specifically limited if it is a visible light laser, It is preferable that it is 400-550 nm from a viewpoint of resolution. Moreover, when using a conductive polymer as resin (b), it is preferable to select the wavelength of a laser in consideration of the absorption wavelength of the conductive polymer. For example, when polyaniline sulfonic acid is used as the resin (b), the laser wavelength is preferably 540 to 650 nm.

In the present invention, the carbon nanotube-containing structure is observed in a confocal mode in a microscope having a confocal optical system. The observation magnification at this time is preferably 100 to 4000 times, and more preferably 500 to 1000 times. By observing at this magnification, the dispersion state of the carbon nanotube (a) in the carbon nanotube-containing structure can be clearly observed.
In addition, by using a microscope having a confocal optical system, the observation plane of the carbon nanotube-containing structure is scanned in the vertical direction (that is, in the thickness direction), and carbon nanotubes existing inside the structure ( a) can be observed. The scanning range (depth) in the vertical direction varies depending on the thickness of the measurement object and the carbon nanotube content, but is preferably 0.1 to 100 μm, more preferably 0.1 to 30 μm. When the carbon nanotube-containing structure is a film, it is preferable to measure the entire range in the thickness direction.
The observation pitch in the thickness direction varies depending on the thickness of the measurement object and the content of carbon nanotubes, but considering the optical thickness of a single slice image observed with a confocal laser microscope, the upper and lower slice images are halved. It is preferable to acquire images so as to overlap each other. Specifically, 0.05 to 1 μm is preferable, and 0.1 to 0.5 μm is more preferable.
The area ratio [A1] and the area ratio [A2] are values unique to each carbon nanotube-containing structure, and do not vary greatly depending on the observation conditions.

The area ratio [A1] and the area ratio [A2] can be obtained by image analysis of the observation image of the carbon nanotube-containing structure observed by the method. Here, the observation image used for image analysis is a superimposed image of slice images acquired in the vertical direction, that is, an extended focus image. An extended focus image is a single image created by extracting only the in-focus portion of a plurality of slice images. Therefore, the area ratio [A1] and the area ratio [A2] can be obtained with high accuracy by analyzing the extended focus image.
The extended focus image is processed by commercially available image processing software to determine the area ratio [A1] and the area ratio [A2]. Specifically, the extended focus image is binarized, the carbon nanotubes in the image are extracted, and the area value and the length of the monodispersed carbon nanotubes and the fine aggregates formed by the carbon nanotubes in the image are measured. Then, the total area occupied by all the carbon nanotubes in the observation area, the total area of the carbon nanotube fine aggregates having a length of 30 μm or more, the area occupied by all the carbon nanotubes in the observation image, and the formula (1) ), The area ratio [A1] and the area ratio [A2] are obtained by the expression (2).
Note that the average value of the area ratio [A1] and the average value of the area ratio [A2] are calculated by observing 3 or more, preferably 5 or more, per sample.

  Furthermore, the distribution state in the thickness direction of the carbon nanotubes present in the carbon nanotube-containing structure can be analyzed from the slice image acquired by the above method. Specifically, an image at a predetermined pitch depth is extracted from the surface of the acquired image, and by using image processing software, carbon nanotubes in the image are extracted by binarization processing, and each occupying in the image The area value of the carbon nanotube and the fine aggregate formed by the carbon nanotube is measured. From the obtained measured value, the area ratio of the carbon nanotubes existing in any part (surface layer, intermediate layer, bottom layer) when being divided into three equal parts in the thickness direction is calculated.

  In the present invention, the carbon nanotubes are preferably contained in 40% by area or more, and more preferably 50% or more, in any part when divided into three equal parts in the thickness direction. If the carbon nanotubes are contained in 40% by area or more in any part when divided into three equal parts in the thickness direction, the carbon nanotubes in the structure form a conductive network by fine aggregation more efficiently. A structure having higher conductivity can be obtained.

<Shape of carbon nanotube-containing structure>
The shape of the carbon nanotube-containing structure in the present invention is not particularly limited, and examples thereof include a sheet shape, a film shape, a film shape, a pellet shape, a rod shape, and a fiber shape. Among these shapes, since the transparency and conductivity of the carbon nanotube-containing structure can be easily utilized, a sheet shape, a film shape, and a film shape are preferable, and a film shape is more preferable.

  Since the film | membrane which consists of a carbon nanotube containing structure can be produced easily, it is preferable that it is a coating film and / or a cured film. The film thickness of the coating film and / or the cured film made of the carbon nanotube-containing structure is preferably 0.01 μm or more, and more preferably 0.1 μm or more in order to achieve sufficient conductivity. In addition, in order to realize sufficient transparency and to suppress defects such as cracks in the coating film and / or cured film, and chipping of the coating film and / or cured film during processing of the structure, 100 μm The following is preferable, and 50 μm or less is more preferable.

<Method for producing carbon nanotube-containing structure>
As a method for producing a carbon nanotube-containing structure in the present invention, for example, (1) a method of molding a carbon nanotube-containing composition comprising a carbon nanotube (a) and a resin (b), (2) a carbon nanotube (a), A method of coating a carbon nanotube-containing composition comprising a resin (b) and a solvent (c); (3) a carbon nanotube (a); and a polymerizable monomer (d) which is a precursor of the resin (b). Examples thereof include a method of polymerizing a polymerizable monomer (d) using a carbon nanotube composition.

  In the production method (1), when the resin (b) is a thermoplastic resin, a structure can be obtained by melting and kneading each component with a general extruder or kneader. . At this time, the carbon nanotubes (a) may be added as they are and dispersed by melting and kneading, or may be pulverized in advance and mixed with the resin (b). Alternatively, a master batch in which the carbon nanotubes (a) are mixed at a high concentration may be manufactured and diluted with the resin (b) so as to obtain a desired concentration of the carbon nanotubes (a).

  When producing a carbon nanotube-containing structure by the production method (1), the average value of the area ratio [A1] is 10% or more and the average value of the area ratio [A2] is 25% or more. The method is not particularly limited as long as the monodispersed carbon nanotubes are finely agglomerated in a fluid state and solidified in that state to maintain and fix the state. For example, optimization of molding temperature, cooling temperature, cooling time, etc. can be mentioned.

In the production method (2), a coating film or a cured film can be obtained from the carbon nanotube-containing composition in which the carbon nanotubes (a) are dispersed in the solvent (c) in which the resin (b) is dissolved or dispersed.
The solvent (c) used in the production method (2) is not particularly limited as long as it can dissolve or disperse the resin (b). For example, water, methanol, ethanol, isopropanol, benzene, toluene , Xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, dimethoxyethane, tetrahydrofuran, chloroform, carbon tetrachloride, ethylene dichloride, ethyl acetate, isobutyl acetate, butyl acetate, cellosolve acetate, methoxyacetate, ethyl lactate, methoxybutanol, Organic solvents such as butyl cellosolve, methylmethoxybutanol, N, N-dimethylformamide, dimethylacetamide, dimethylsulfoxide, and water-containing organic solvents can be used. These solvents may be used alone or in combination of two or more.

In the production method (2), the dispersant (e) may be used in combination from the viewpoint of improving the dispersibility of the carbon nanotube (a). Although the dispersing agent which can be used is not specifically limited, For example, surfactant and a polymeric dispersing agent can be illustrated.
Specific examples of surfactants include alkylsulfonic acid, alkylbenzenesulfonic acid, alkylcarboxylic acid, alkylnaphthalenesulfonic acid, α-olefinsulfonic acid, dialkylsulfosuccinic acid, α-sulfonated fatty acid, N-methyl-N-oleyl. Taurine, petroleum sulfonic acid, alkyl sulfuric acid, sulfated oil, polyoxyethylene alkyl ether sulfuric acid, polyoxyethylene styrenated phenyl ether sulfuric acid, alkyl phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylene alkyl phenyl ether phosphoric acid, Anionic surfactants such as naphthalenesulfonic acid formaldehyde condensates and their salts; primary to tertiary fatty amines, tetraalkylammonium salts, trialkylbenzylammonium salts, alkylpyridini Um salt, 2-alkyl-1-alkyl-1-hydroxyethylimidazolinium salt, N, N-dialkylmorpholinium salt, polyethylene polyamine fatty acid amide and salt thereof, urea condensate of polyethylene polyamine fatty acid amide and salt thereof, Cationic surfactants such as quaternary ammonium salts of urea condensates of polyethylene polyamine fatty acid amides; N, N-dimethyl-N-alkyl-N-carboxymethylammonium betaine, N, N, N-trialkyl-N- Betaines such as sulfoalkylene ammonium betaine, N, N-dialkyl-N, N-bispolyoxyethylene ammonium sulfate betaine, 2-alkyl-1-carboxymethyl-1-hydroxyethylimidazolinium betaine, N, N— Dialkylaminoalkyl Amphoteric surfactants such as aminocarboxylic acids such as carboxylates; polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene-polyoxypropylene glycol, polyoxyethylene-poly Oxypropylene alkyl ether, polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, polyoxyethylenated castor oil, fatty acid diethanolamide, polyoxyethylene alkylamine, Nonionic surfactants such as triethanolamine fatty acid partial esters and trialkylamine oxides; and fluoroalkylcarboxylic acids Perfluoroalkyl carboxylic acids, perfluoroalkyl benzene sulfonic acids, fluorine-based surfactants such as perfluoroalkyl polyoxyethylene ethanol is used. Here, the alkyl group preferably has 1 to 24 carbon atoms, and more preferably 3 to 18 carbon atoms. Two or more surfactants may be used.

  As the polymer dispersant, for example, a (meth) acrylic polymer containing a polar group described in JP-A-2006-225632 can be suitably used. Moreover, a conductive polymer can also be used from a viewpoint of the dispersibility of a carbon nanotube (a) and the electroconductivity of the structure obtained. As the conductive polymer, the same polymers as mentioned for the resin (b) can be used.

  The carbon nanotube-containing composition in the production method (2) may be prepared by dissolving or dispersing the resin (b) in the solvent (c) in advance, and then adding and dispersing the carbon nanotube (a). The carbon nanotubes (a) and the resin (b) may be added all at once to perform a dispersion treatment. Alternatively, a master batch in which carbon nanotubes (a) are dispersed at a high concentration may be produced and diluted with a solvent (c) so as to obtain a desired concentration of carbon nanotubes (a).

  When producing a carbon nanotube-containing structure by the production method (2), the average value of the area ratio [A1] is 10% or more, and the average value of the area ratio [A2] is 25% or more. The method is not particularly limited as long as the monodispersed carbon nanotubes are finely agglomerated in a fluid state and solidified in that state to maintain and fix the state. For example, the coating method, drying time, drying temperature, resin amount, dispersant amount, dispersant type, solvent type, optimization of the viscosity of the carbon nanotube-containing composition, and the like can be mentioned.

In the production method of (3), a molded article is obtained by polymerizing the polymerizable monomer using a carbon nanotube-containing composition containing the polymerizable monomer (d) which is a precursor of the resin (b). A coating film etc. can be manufactured.
The polymerizable monomer (d) used here is not particularly limited. For example, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylic compound having two or more polymerizable groups, urethane (Meth) acrylate, styrene, methylstyrene, bromostyrene, vinyltoluene, divinylbenzene, vinyl acetate, N-vinylcaprolactam, N-vinylpyrrolidone and the like. Among these, from the viewpoint of transparency, impact resistance, scratch resistance, and easy moldability of the obtained carbon nanotube-containing structure, two or more (meth) acrylic acid, (meth) acrylic acid ester, and polymerizable group A (meth) acrylic compound and a urethane (meth) acrylate compound are preferably used.

  The polymerizable monomer (d) may be used alone or in combination of two or more. In the present invention, “(meth) acryl” is a generic term for “methacryl” and “acryl”, and “(meth) acryloyl” is a generic term for “methacryloyl” and “acryloyl”.

  (Meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic. I-butyl acid, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, (meth) Dimethylaminoethyl acrylate, diethylaminoethyl (meth) acrylate , Ethyl trimethylammonium chloride (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, (meth) acrylic acid 1,4-butanediol and the like can be mentioned.

  Examples of the (meth) acrylic compound having two or more polymerizable groups include (i) an esterified product obtained by reacting 2 mol or more of (meth) acrylic acid or a derivative thereof with 1 mol of polyhydric alcohol; ii) A linear ester having two or more (meth) acryloyloxy groups in one molecule obtained from a polyhydric alcohol, a polyvalent carboxylic acid or an anhydride thereof, and (meth) acrylic acid or a derivative thereof. (Iii) poly [(meth) acryloyloxyethyl] isocyanurate; (iv) epoxy polyacrylate and the like.

  Examples of the esterified product (i) include polyethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin tri (meth) acrylate, dipentaerythritol tri ( (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tripentaerythritol te La (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol hepta (meth) acrylate.

  In the esterified product (ii), preferred combinations of polycarboxylic acid or its anhydride / polyhydric alcohol / (meth) acrylic acid include malonic acid / trimethylolethane / (meth) acrylic acid, malonic acid / trimethylol. Propane / (meth) acrylic acid, malonic acid / glycerin / (meth) acrylic acid, malonic acid / pentaerythritol / (meth) acrylic acid, succinic acid / trimethylolethane / (meth) acrylic acid, succinic acid / trimethylolpropane / (Meth) acrylic acid, succinic acid / glycerin / (meth) acrylic acid, succinic acid / pentaerythritol / (meth) acrylic acid, adipic acid / trimethylolethane / (meth) acrylic acid, adipic acid / trimethylolpropane / (Meth) acrylic acid, adipic acid / glycerin / (meta Acrylic acid, adipic acid / pentaerythritol / (meth) acrylic acid, glutaric acid / trimethylolethane / (meth) acrylic acid, glutaric acid / trimethylolpropane / (meth) acrylic acid, glutaric acid / glycerin / (meth) acrylic Acid, glutaric acid / pentaerythritol / (meth) acrylic acid, sebacic acid / trimethylolethane / (meth) acrylic acid, sebacic acid / trimethylolpropane / (meth) acrylic acid, sebacic acid / glycerin / (meth) acrylic acid , Sebacic acid / pentaerythritol / (meth) acrylic acid, fumaric acid / trimethylolethane / (meth) acrylic acid, fumaric acid / trimethylolpropane / (meth) acrylic acid, fumaric acid / glycerin / (meth) acrylic acid, Fumaric acid / pentaerythritol / (me TA) acrylic acid, itaconic acid / trimethylolethane / (meth) acrylic acid, itaconic acid / trimethylolpropane / (meth) acrylic acid, itaconic acid / glycerin / (meth) acrylic acid, itaconic acid / pentaerythritol / (meta) ) Acrylic acid, maleic anhydride / trimethylolethane / (meth) acrylic acid, maleic anhydride / trimethylolpropane / (meth) acrylic acid, maleic anhydride / glycerin / (meth) acrylic acid, maleic anhydride / pentaerythritol / (Meth) acrylic acid and the like.

  (Iii) Examples of poly [(meth) acryloyloxyethyl] isocyanurate include di- or tri (meth) acrylate of tris (2-hydroxyethyl) isocyanuric acid.

Urethane (meth) acrylate is a reaction product of a hydroxyl group-containing (meth) acrylate compound and an isocyanate compound.
Examples of the hydroxyl group-containing (meth) acrylate compound include a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

(Wherein R ¹¹ represents a hydrogen atom or a methyl group, R ¹² is any hydrocarbon group having 2 to 24 carbon atoms which may contain an ether bond, and m ₁ and n ₁ are each 1 or more, and (M ₁ + n ₁ ) represents an integer less than or equal to the carbon number of R ^12. )

(In the formula, R ²¹ represents a hydrogen atom or a methyl group, and R ²² represents any alkylene group having 2 to 24 carbon atoms, any arylene group having 1 to 24 carbon atoms, or any one having 1 to 24 carbon atoms. And n ₂ represents any integer of 1 to 100.)

Specifically, a compound having one (meth) acrylate group and one hydroxyl group (a compound represented by the general formula (1) in which both m ₁ and n ₁ are 1, a compound represented by the general formula (2)) ) As 1-hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-1,1-dimethylethyl (meth) acrylate, ( 3-hydroxypropyl (meth) acrylate, 2-hydroxy-1-methylethyl (meth) acrylate, 3-hydroxy-2-methylpropyl (meth) acrylate, 2-hydroxy-2-methylpropyl (meth) acrylate 1- (hydroxymethyl) propyl (meth) acrylate, hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, (Meth) acrylic acid 2-hydroxy-1-methylpropyl, (meth) acrylic acid 3-hydroxy-1-methylpropyl, (meth) acrylic acid 4-hydroxybutyl, (meth) acrylic acid 2-hydroxypentyl, (meta ) 6-hydroxyhexyl acrylate, 2-hydroxyhexyl (meth) acrylate, 2-hydroxyheptyl (meth) acrylate, 2-hydroxyoctyl (meth) acrylate, 2- (meth) acrylic acid 2-((6- Hydroxyhexanoyl) oxy) ethyl, 2-hydroxy-3-methoxypropyl (meth) acrylate, 3-butoxy-2-hydroxypropyl (meth) acrylate, 9-hydroxy-10-methoxydecyl (meth) acrylate, (Meth) acrylic acid 2,2-dimethyl-3-hydroxypropyl, (meth) a 3-hydroxybutyl toluate, 3-methyl-3-hydroxybutyl (meth) acrylate, 1-methyl-3hydroxypropyl (meth) acrylate, 2- (2-hydroxyethoxy) ethyl (meth) acrylate, ( 2- (2- (2- (2-hydroxyethoxy) ethoxy) ethoxy) ethyl (meth) acrylate, 2- (2- (2- (2-hydroxyethoxy) ethoxy) ethoxy) ethyl (meth) acrylate, decaethylene glycol ( (Meth) acrylate, tridecaethylene glycol (meth) acrylate, (meth) acrylic acid 17-hydroxy-3,6,9,12,15-pentaoxaheptadecan-1-yl, (meth) acrylic acid 20-hydroxy-3 , 6,9,12,15,18-hexaoxaicosan 1-yl, 2- (meth) acrylic acid 2-me Ru-2- (3-hydroxy-2,2-dimethylpropoxycarbonyl) propyl, (meth) acrylic acid 3- [3- (3-hydroxypropyl) -3-oxopropoxy] -3-oxopropyl, (meth) 2-hydroxy-3-allyloxypropyl acrylate, 1-phenyl-2-hydroxyethyl (meth) acrylate, 4-hydroxyphenyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, ( 2- (4-hydroxyphenyl) ethyl (meth) acrylate, 2-[(2-hydroxybenzyl) oxy] ethyl (meth) acrylate, 2- (4-hydroxyphenoxy) ethyl (meth) acrylate, (meth) 3-hydroxy-4-acetylphenyl acrylate, 4- (hydroxymethyl) acrylate with (meth) acrylic acid Chlohexylmethyl, 3-hydroxy-4-benzoylphenyl (meth) acrylate, 1- (hydroxymethyl) tridecyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 2-hydroxytetra (meth) acrylate Examples include decyl.

Further, as a compound having one (meth) acrylate group and two or more hydroxyl groups (a compound represented by the general formula (1) in which m ₁ is 1 and n ₁ is 2), (meth) acrylic acid 3, 4 -Dihydroxybutyl, 2,2-bis (hydroxymethyl) butyl (meth) acrylate, 2-hydroxy-1-hydroxymethylethyl (meth) acrylate, 1,1-bis (hydroxymethyl) ethyl (meth) acrylate , 2,3-dihydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, 2-hydroxy-1-hydroxymethylpropyl (meth) acrylate, 3-hydroxy-2 (meth) acrylate -(Hydroxymethyl) propyl, (meth) acrylic acid 2,3-dihydroxy-1-methylpropyl, (meth) acrylic acid 2,4-dihi Roxybutyl, 2-methyl-3-hydroxy-2- (hydroxymethyl) propyl (meth) acrylate, 2,3-dihydroxy-2-methylpropyl (meth) acrylate, 3-hydroxy-1- (meth) acrylate (Hydroxymethyl) propyl, (meth) acrylic acid 9,10-dihydroxydecyl, (meth) acrylic acid 2,3-dihydroxy-2- (hydroxymethyl) propyl, (meth) acrylic acid 2-hydroxy-1,1- Bis (hydroxymethyl) ethyl, pentaerythritol mono (meth) acrylate, 2,3,4-trihydroxybutyl (meth) acrylate, 1- (hydroxymethyl) -2,3-dihydroxypropyl (meth) acrylate, etc. Can be mentioned.

Further, as a compound having two or more (meth) acrylate groups and one or more hydroxyl groups (a compound represented by the general formula (1) in which m ₁ is 2 and n ₁ is 1), di (meth) acrylic acid 2-hydroxytrimethylene, di (meth) acrylic acid 2-hydroxy-2-methyltrimethylene, bis (meth) acrylic acid 2-hydroxymethyl-2-methyl-1,3-propanediyl, di (meth) acrylic acid 2-Ethyl-2- (hydroxymethyl) trimethylene, 2- (hydroxymethyl) -1,3-propanediyl di (meth) acrylate, 2-hydroxy-1-methyl-1,3-bis (meth) acrylate Propanediyl, bis (meth) acrylic acid 1- (2-hydroxyethyl) -1,2-ethanediyl, bis (meth) acrylic acid 1-hydroxymethyl-1,2-ethanedi Bis (meth) acrylic acid 1- (1-hydroxyethyl) -1,2-ethanediyl, bis (meth) acrylic acid 1-hydroxymethyl-2-methyl-1,2-ethanediyl, bis (meth) acrylic acid 1- (hydroxymethyl) -1-methylethylene, 2-hydroxy-1,4-butanediyl bis (meth) acrylate, 1- (hydroxymethyl) -1,3-propanediyl bis (meth) acrylate, bis ( 2- (Methyl) acrylic acid 2-hydroxy-1,6-hexanediyl, bis (meth) acrylic acid 1- (2-hydroxypropoxymethyl) ethylenebis [oxy (1-methyl-2,1-ethanediyl)], bis (meta ) Acrylic acid 2- (2-hydroxypropoxy) -1,3-propanediylbis [oxy (1-methyl-2,1-ethanediyl)] , (Meth) acrylic acid 8- (2-hydroxypropoxy) -1,4,12-trimethyl-14-oxo-3,6,10,13-tetraoxa-15-hexadecene-1-yl, (meth) acrylic acid 2-hydroxy-3-[(2-methyl-1-oxo-2-propenyl) oxy] propyl, pentaerythritol tri (meth) acrylate, tris (meth) acrylic acid 2- (hydroxymethyl) propane-1,2,3 -Triyl, bis (meth) acrylic acid 2- (acryloyloxymethyl) -2-hydroxypropane-1,3-diyl, tris (meth) acrylic acid 3- (hydroxymethyl) propane-1,2,3-triyl, Tris (meth) acrylic acid 3-hydroxybutane-1,2,4-triyl, (meth) acrylic acid 3- [2,2-bis [( (Meth) acryloyloxy) methyl] -3-hydroxypropoxy] -2,2-bis [((meth) acryloyloxy) methyl] propyldipentaerythritol penta (meth) acrylate, bis (meth) acrylic acid 2-[[[[ 2- (hydroxymethyl) -2-[(((meth) acryloyloxy) methyl] -3-((meth) acryloyloxy) propyl] oxy] methyl] -2-[((meth) acryloyloxy) methoxy] propane- 1,3-diyl and the like can be mentioned.

Further, as a compound having two or more (meth) acrylate groups and two or more hydroxyl groups (a compound represented by the general formula (1) in which m ₁ is 2 and n ₁ is 2), bis (meth) acrylic is used. Acid 2,3-dihydroxybutane-1,4-diyl, bis (meth) acrylic acid 2-hydroxy-2- (hydroxymethyl) propane-1,3-diyl, di (meth) acrylic acid 2,2-bis ( Hydroxymethyl) -1,3-propanediyl, bis (meth) acrylic acid 2-hydroxy-3- (hydroxymethyl) propane-1,3-diyl, bis (meth) acrylic acid 1,1-bis (hydroxymethyl) Ethylene, bis (meth) acrylic acid 1- (1,2-dihydroxyethyl) ethane-1,2-diyl, bis (meth) acrylic acid 1,2-bis (hydroxymethyl) ethylene, bis ( T) Acrylic acid 1,6-hexanediylbis (oxy) bis (2-hydroxy-3,1-propanediyl), bis (meth) acrylic acid (2,11-dihydroxy-4,9-dioxadodecane)- 1,12-diyl, bis (meth) acrylic acid 2,9-dihydroxy-4,7-dioxadecane-1,10-diyl, di (meth) acrylic acid 3,3 '-(1,3-phenylenebisoxy) Bis (2-hydroxypropyl) and the like can be mentioned.
These hydroxyl group-containing (meth) acrylate compounds may be used alone or in combination of two or more.

  Among hydroxyl group-containing (meth) acrylate compounds, from the viewpoint of reactivity with isocyanate compounds, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxytri (di) methacrylate. Methylene, pentaerythritol tri (meth) acrylate, 2- (2-hydroxyethoxy) ethyl (meth) acrylate, 8-hydroxy-3,6-dioxaoctane-1-yl (meth) acrylate, (meth) acryl Acid 2- [2- [2- (2-hydroxyethoxy) ethoxy] ethoxy] ethyl, decaethylene glycol (meth) acrylate, undecaethylene glycol (meth) acrylate, dodecaethylene glycol (meth) acrylate, tridecaethylene glycol (Meth) acrylate, (meta 17-hydroxy-3,6,9,12,15-pentaoxaheptadecan-1-yl acrylate, 20-hydroxy-3,6,9,12,15,18-hexaoxaicosane (meth) acrylate -1-yl is particularly preferably used.

  Examples of the isocyanate compound include isocyanates, diisocyanates, triisocyanates, polyisocyanates, and the like. Among these, a diisocyanate compound and / or a triisocyanate compound are preferable from the viewpoint of mechanical properties.

  Examples of isocyanates include phenyl isocyanate, isocyanate nitrile, naphthyl isocyanate, vinyl isocyanate, and the like.

  Diisocyanates include aliphatic diisocyanates such as ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, lysine methyl ester diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and dimer diisocyanate. , Cyclophoric diisocyanates such as isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), ω, ω'-diisocyanate dimethylcyclohexane, xylylene diisocyanate, α, α, α ', α'-tetramethyl Aliphatic diisocyanates having an aromatic ring such as xylylene diisocyanate, benzene-1,3-diisocyanate Benzene diisocyanates such as benzene-1,4-diisocyanate; toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,5-diisocyanate, etc. 1,2-xylene-3,5-diisocyanate, 1,2-xylene-3,6-diisocyanate, 1,2-xylene-4,6-diisocyanate, 1,3-xylene-2,4 -Diisocyanate, 1,3-xylene-2,5-diisocyanate, 1,3-xylene-2,6-diisocyanate, 1,3-xylene-4,6-diisocyanate, 1,4-xylene-2,5-diisocyanate Xylene diisocyanates such as 1,4-xylene-2,6-diisocyanate Aromatic diisocyanates such as preparative acids and the like.

  Examples of the triisocyanates include benzene triisocyanates such as benzene-1,2,4-triisocyanate, benzene-1,2,5-triisocyanate, and benzene-1,3,5-triisocyanate; , 3,5-triisocyanate, toluene-2,3,6-triisocyanate, toluene-2,4,5-triisocyanate, toluene-2,4,6-triisocyanate, toluene-3,4,6-triisocyanate Isocyanates, toluene isocyanates such as toluene-3,5,6-triisocyanate, 1,2-xylene-3,4,6-triisocyanate, 1,2-xylene-3,5,6-triisocyanate, , 3-xylene-2,4,5-triisocyanate, 1,3-xylene-2,4,6-trii Xylene trioxide such as cyanate, 1,3-xylene-3,4,5-triisocyanate, 1,4-xylene-2,3,5-triisocyanate, 1,4-xylene-2,3,6-triisocyanate Aromatic triisocyanates such as isocyanates, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane Aliphatic, alicyclic or heteroatom-containing triisocyanates such as triisocyanate, tris (isocyanatephenylmethane), tris (isocyanatephenyl) thiophosphate, and the like can be mentioned.

  Examples of polyisocyanates include diisocyanates, trimers of triisocyanates, and polyol adducts thereof.

  Examples of the diisocyanates and triisocyanates include a compound represented by the following general formula (3), a compound represented by the following general formula (4), a compound represented by the following general formula (5), and the like.

(In the formula, R ³¹ represents hydrogen or any alkyl group having 1 to 8 carbon atoms, and n ₃ represents any integer of 1 to 25. When n ₃ is 2 or more, R ³¹ represents R ^31. 2 may be present, but each R ³¹ may be the same or different.)

(Wherein R ^{41 to} R ⁴³ each independently represents a divalent group selected from the group consisting of an alkylene group having 1 to 24 carbon atoms, an arylene group, and an aralkylene group.)

(In the formula, R ⁵¹ is a group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an aryl group, and an aralkyl group, m ₂ is an integer of 0 to 4, and n ₄ is an integer of 2 to 6, and (m ₂ + n ₄ ) is an integer of 6 or less, and when m ₂ is 2 or more, R ⁵¹ is also 2 or more. R ⁵¹ may be the same or different.)

  Examples of the compound having two isocyanate groups in the molecule represented by the general formula (3) include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, Examples include octamethylene diisocyanate.

  As the compound having three isocyanate groups in the molecule represented by the general formula (4), a compound composed of a trimer of a compound having two isocyanate groups is preferable. As the compound having two isocyanate groups, the above-mentioned various diisocyanates can be used.

  As an aromatic isocyanate compound represented by the general formula (5), benzene-1,3-diisocyanate, benzene-1,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene- 2,6-diisocyanate, toluene-3,5-diisocyanate, 1,2-xylene-3,5-diisocyanate, 1,2-xylene-3,6-diisocyanate, 1,2-xylene-4,6-diisocyanate, 1,3-xylene-2,4-diisocyanate, 1,3-xylene-2,5-diisocyanate, 1,3-xylene-2,6-diisocyanate, 1,3-xylene-4,6-diisocyanate, 1, 4-xylene-2,5-diisocyanate, 1,4-xylene-2,6-diisocyanate Etc. The.

  Among the isocyanate compounds described above, hexamethylene diisocyanate, hexamethylene diisocyanate trimer, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,5-diisocyanate, 1,2-xylene-3,5-diisocyanate, 1,2-xylene-3,6-diisocyanate, 1,2-xylene-4,6-diisocyanate, 1,3-xylene-2,4-diisocyanate, 1, 3-xylene-2,5-diisocyanate, 1,3-xylene-2,6-diisocyanate, 1,3-xylene-4,6-diisocyanate, 1,4-xylene-2,5-diisocyanate, 1,4- Xylene-2,6-diisocyanate is particularly preferably used . These compounds may be used alone or in combination of two or more.

  Among the urethane (meth) acrylate compounds, from the viewpoint of dispersibility of the carbon nanotube (a), a hydroxyl group-containing (meth) acrylate represented by the general formula (1) or a hydroxyl group-containing (meta) represented by the general formula (2) ) A reaction product of an acrylate and any of the isocyanate represented by the general formula (3), the isocyanate represented by the general formula (4), and the isocyanate represented by the general formula (5) is particularly preferably used.

  In the production method (3), in order to polymerize the polymerizable monomer (d) in the carbon nanotube-containing composition with heat and / or light, a polymerization initiator may be used in combination. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator.

As photopolymerization initiators, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, etc. Carbonyl compounds; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoy Examples include rudiethoxyphosphine oxide. Commercially available photopolymerization initiators include “Irgacure 184” (manufactured by Ciba Specialty Chemicals), “Irgacure 907” (manufactured by Ciba Specialty Chemicals), and “Darocur 1173” (Merck Japan Co., Ltd.), “Ezacure KIP100F” (Nihon Sebel Hegner Co., Ltd.) and the like.
A photoinitiator may be used individually by 1 type and may use 2 or more types together.

Examples of the thermal polymerization initiator include radical polymerization initiators such as azo compounds, organic peroxides, and redox polymerization initiators.
As the azo compound, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (isobutyric acid) dimethyl, 4,4 ′ -Azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis {2-methyl-N- [2- (1-hydroxybutyl)]- Propionamide} and the like.
Examples of the organic peroxide include benzoyl peroxide and lauroyl peroxide.
Examples of redox polymerization initiators include combinations of organic peroxides and amines.
A thermal polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

  In the production method (3), the solvent (c) may be used in combination. In this case, the solvent (c) is not particularly limited, but a solvent (c) in which the polymerizable monomer (d) is dissolved is preferable. Moreover, in order to improve the dispersibility of a carbon nanotube, you may use together the said dispersing agent (e).

  In the carbon nanotube-containing composition in the production method of (3), the carbon nanotube (a) may be added to the polymerizable monomer (d) and dispersed, or when the solvent (c) is used in combination, The polymerizable monomer (d) may be previously dissolved in the solvent (c), and the carbon nanotube (a) may be added and dispersed. When mixing and using a plurality of polymerizable monomers (d), after adding carbon nanotubes (a) to one type of polymerizable monomer (d) and dispersing, You may dilute with a monomer (d) and / or a solvent (c).

  When producing a carbon nanotube-containing structure by the production method (3), the average value of the area ratio [A1] is 10% or more and the average value of the area ratio [A2] is 25% or more. The method is not particularly limited as long as the monodispersed carbon nanotubes are finely agglomerated in a fluid state and solidified in that state to maintain and fix the state. For example, coating method, time from coating to curing, curing temperature, polymerizable monomer species, dispersant species, dispersant amount, solvent species, solvent amount, viscosity of carbon nanotube-containing composition, drying temperature, drying Time optimization can be mentioned.

In the production method (2) and the production method (3), a stirring or kneading apparatus such as an ultrasonic wave, a homogenizer, a spiral mixer, a planetary mixer, a disperser, or a hybrid mixer is used when mixing the components. be able to. In particular, when performing the dispersion treatment of the carbon nanotube (a), it is preferable to irradiate this with ultrasonic waves. In this case, it is particularly preferable to perform the treatment by using ultrasonic irradiation and a homogenizer in combination (ultrasonic homogenizer). preferable. The conditions of the ultrasonic irradiation treatment are not particularly limited, but if the ultrasonic wave intensity and the treatment time are sufficient for the carbon nanotubes (a) to be uniformly dispersed or dissolved in the carbon nanotube-containing composition. Good. For example, the rated output in the ultrasonic oscillator is preferably 0.1 to 2.0 watt / cm ² per unit bottom area of the ultrasonic oscillator, more preferably in the range of 0.3 to 1.5 watt / cm ² . It is. The oscillation frequency is preferably 10 to 200 kHz, more preferably 20 to 100 kHz. Further, the time of the ultrasonic irradiation treatment is preferably 1 minute to 48 hours, more preferably 5 minutes to 48 hours. Thereafter, the dispersion or dissolution may be further thoroughly performed using a ball-type kneader such as a ball mill, a vibration mill, a sand mill, or a roll mill.

  Further, the temperature of the carbon nanotube-containing composition when performing the ultrasonic irradiation treatment is preferably 60 ° C. or less, more preferably 40 ° C. or less, from the viewpoint of improving dispersibility. In particular, when preparing a carbon nanotube-containing composition using the polymerizable monomer (d), 40 ° C. or lower is more preferable from the viewpoint of preventing polymerization.

(Complex)
The composite of the present invention has a film-like carbon nanotube-containing structure on one side or both sides of a substrate.
Examples of the base material include synthetic resin films, sheets, foams, porous membranes, elastomers, various molded products; wood, paper materials, ceramics, fibers, nonwoven fabrics, carbon fibers, carbon fiber paper, glass plates, stainless steel plates Etc.

  Examples of the synthetic resin constituting the substrate include polyethylene, polyvinyl chloride, polypropylene, polystyrene, acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-styrene resin (AS resin), acrylic resin, methacrylic resin, polybutadiene, Polycarbonate, polyarylate, polyvinylidene fluoride, polyester, polyamide, polyimide, polyaramid, polyphenylene sulfide, polyether ether ketone, polyphenylene ether, polyether nitrile, polyamide imide, polyether sulfone, polysulfone, polyether imide, polybutylene terephthalate, A polyurethane is mentioned. A synthetic resin may be used individually by 1 type, and may be used as a mixture of 2 or more types.

  The composite of the present invention is excellent in transparency because the carbon nanotube (a) is dispersed or dissolved in the film with high dispersibility. Therefore, the total light transmittance of the composite of the present invention is 50% or more, particularly 70% or more, and can be suitably used as a transparent conductive film, a transparent conductive sheet, and a transparent conductive molded body.

  In the composite of the present invention, an antireflection film may be provided on the film-like carbon nanotube-containing structure as necessary. Alternatively, a film-like carbon nanotube-containing structure may be provided on one side of the substrate, and another functional thin film such as an antireflection film, a diffusion layer, or an adhesive layer may be provided on the other side.

<Method for producing composite>
As a method for producing the composite, for example, (i) a method in which a carbon nanotube-containing composition is applied to the surface of a substrate and cured; (ii) a carbon nanotube-containing composition is applied to the inner surface of the mold and cured. Forming a cured film by pouring a polymerizable raw material or molten resin into the mold and solidifying it to form a base material, and peeling the cured film from the mold together with the base material; (iii) between the mold and the base material For example, a method in which a carbon nanotube-containing composition is poured and cured to form a cured film, and then the cured film is peeled off from the mold together with the substrate.

  Examples of the coating method of the carbon nanotube-containing composition in the method (i) include a gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, phanten coater, rod coater, and air doctor. Examples thereof include a method using a coater, knife coater, air knife coater, blade coater, cast coater, screen coater and the like, a spraying method such as air spray and airless spray, and a dipping method such as dip.

Among the methods (i) to (iii), the method (ii) is preferable because a cured film having a good surface state can be obtained without deteriorating the appearance due to the influence of dust or the like.
Examples of the mold used in the method (ii) include casting polymerization molds and molding molds. When the mold is composed of two plate-like products having a smooth surface, a plate-like laminate having a smooth surface can be obtained. At this time, the cured film may be formed with only one mold or with both molds.

As a method for forming a substrate in the method (ii), a so-called cast polymerization method is preferred in which a polymerizable raw material is injected into a casting polymerization mold and polymerized.
As the cast polymerization method, for example, a carbon nanotube-containing composition prepared by using a carbon nanotube (a), a polymerizable monomer (d), and a photopolymerization initiator is used for a casting polymerization glass mold comprising a glass plate. An example is a method in which a polymerized raw material is poured into a glass mold and polymerized after being applied to the inner surface and photocured. In the glass mold, for example, a gasket made of soft polyvinyl chloride, ethylene-vinyl acetate copolymer, polyethylene, ethylene-methyl methacrylate copolymer or the like is sandwiched between two glass plates, and these are fixed with a clamp or the like. Is assembled.

  The cast polymerization method can also be performed continuously. Examples of the continuous cast polymerization method include a method of polymerizing methyl methacrylate or the like between two steel belts using an apparatus described in JP-B-46-41602. In this continuous cast polymerization method, for example, carbon steel containing a polymerizable monomer (d) and a photopolymerization initiator or a polymerizable monomer (d) and a thermal polymerization initiator are used on the steel belt surface. The composition is applied and cured to form a cured film. Moreover, if the design, such as an unevenness | corrugation, is previously given to the steel belt surface, the composite_body | complex which has the designability on the surface can be manufactured. Further, a film having irregularities on the surface and not dissolved or swollen in the carbon nanotube-containing composition is attached to a steel belt, and the polymerizable monomer (d) and the photopolymerization initiator or polymerizable monomer are formed on the irregular surface. The carbon nanotube-containing composition prepared using the monomer (d) and the thermal polymerization initiator may be applied and cured.

As a polymerizable raw material, from the viewpoint of transparency of the composite, a monomer component mainly composed of (meth) acrylic acid or (meth) acrylic acid ester, a polymer in which a part of this monomer component is polymerized And a mixture of monomer components are preferred.
(Meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acrylic Cyclohexyl acid, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth) acryldimethylaminoethyl, diethylaminoethyl (meth) acrylate, ethyl trimethylammonium (meth) acrylate Examples include chloride.

The monomer component contains other polymerizable monomers such as styrene, methylstyrene, bromostyrene, vinyltoluene, divinylbenzene, vinyl acetate, N-vinylcaprolactam, N-vinylpyrrolidone as necessary. May be. Another polymerizable monomer may be used individually by 1 type, and 2 or more types may be mixed and used for it.
The polymerization rate of the monomer component in the mixture of the polymer obtained by partially polymerizing the monomer component and the monomer component is preferably 35% by mass or less.

  A chain transfer agent may be added to the polymerizable raw material. The chain transfer agent is preferably a mercaptan chain transfer agent such as an alkyl mercaptan having 2 to 20 carbon atoms, mercapto acid, thiophenol or a mixture thereof, and a mercaptan having a short alkyl chain such as n-octyl mercaptan or n-dodecyl mercaptan. Is particularly preferred.

  When the polymerizable raw material is polymerized by heating, a radical polymerization initiator such as an azo compound, an organic peroxide, or a redox polymerization initiator may be added. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvalero). Nitrile) and the like. Examples of the organic peroxide include benzoyl peroxide and lauroyl peroxide. Examples of redox polymerization initiators include combinations of organic peroxides and amines.

  When the polymerizable raw material is polymerized by ultraviolet irradiation, a photopolymerization initiator such as a phenyl ketone compound or a benzophenone compound may be added. Commercially available photopolymerization initiators include “Irgacure 184” (manufactured by Ciba Specialty Chemicals), “Irgacure 907” (manufactured by Ciba Specialty Chemicals), “Darocur 1173” (Merck Japan ( Co., Ltd.), “Ezacure KIP100F” (Nihon Sebel Hegner Co., Ltd.), and the like.

  Further, when the polymerizable raw material is polymerized by ultraviolet irradiation, a photosensitizer may be added. Examples of photosensitizers include benzoin, benzoin ethyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, azobisisobutyronitrile, benzoyl peroxide, and the like. Is mentioned. Moreover, you may add the photosensitizer which has a sensitizing effect | action in the wavelength range below 400 nm.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, a following example does not limit the scope of the present invention. The raw material carbon nanotubes were multi-walled carbon nanotubes. Hereinafter, the multi-walled carbon nanotube is sometimes referred to as MWNT.

(Production Example 1)
Urethane compound 1:
Urethane compound 1 was obtained by reacting 3 mol of 2-hydroxytrimethylene dimethacrylate with 1 mol of triisocyanate composed of a trimer of hexamethylene diisocyanate.

(Preparation Example 1)
Carbon nanotube-containing composition 1
32 parts by mass of urethane compound 1 of Production Example 1, 58 parts by mass of 1,6-hexanediol diacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 4 parts by mass of pentaerythritol tetraacrylate, and 6 parts by mass of pentaerythritol triacrylate The mixed polymerizable monomer was mixed with 0.05 part by mass of the multi-walled carbon nanotube at room temperature. This mixture was subjected to ultrasonic homogenizer treatment (vibra cell 20 kHz, manufactured by SONIC) for 1 hour under ice cooling, and then 1.5 parts by mass of benzoin ethyl ether was added as a photopolymerization initiator to prepare a carbon nanotube-containing composition 1 Was prepared.

(Examples 1-3)
Carbon nanotube-containing structures 1 to 3
The carbon nanotube-containing composition 1 is dropped on an acrylic resin plate (thickness 3 mm), and a polyethylene terephthalate (PET) film (manufactured by Teijin Ltd.) having a thickness of 50 μm is disposed thereon, and has a JIS hardness of 30 °. Ironing with a rubber loom, the thickness of the composition was adjusted to 10 μm. Thereafter, the composition is precured by passing it through a position of 10 cm below a fluorescent ultraviolet lamp with an output of 40 W (manufactured by Toshiba Corporation, FL40BL) at a speed of 0.8 m / min with the PET film surface facing up. After that, the PET film was peeled off. Next, a carbon nanotube-containing structure is formed on the surface by passing the position 20 cm below the high-pressure mercury lamp with an output of 30 W / cm at a speed of 0.8 m / cm with the coating film facing upward to fully cure the composition. A composite having a cured film consisting of was obtained. The time from the formation of the coating film by the rubber roll to the start of preliminary curing was 1 minute in Example 1, 3 minutes in Example 2, and 15 minutes in Example 3.

(Comparative Example 1)
Carbon nanotube-containing structure 4
A carbon nanotube-containing structure 4 was obtained in the same manner as in Examples 1 to 3, except that the time from the formation of the coating film by the rubber roll to the start of preliminary curing was 30 seconds (0.5 minutes).

<Evaluation method>
For the carbon nanotube-containing structures 4 of Examples 1 to 3 and Comparative Example 1, the surface resistance value and the total light transmittance were measured as follows. Moreover, it observed with the confocal laser microscope, the average value of area ratio [A1] and the average value of area ratio [A2] were calculated, and also the dispersion state of the carbon nanotube of thickness direction was analyzed. The results are shown in Table 1.
(Surface resistance value)
The surface resistance value was measured with Hiresta UP (manufactured by Mitsubishi Chemical Corporation) at an applied voltage of 500 V under the conditions of a temperature of 25 ° C. and a relative humidity of 50%.
(Total light transmittance)
The total light transmittance (%) was measured with a Nippon Denshoku haze meter NDH2000.

(Observation of carbon nanotube-containing structures)
Observation of the carbon nanotube-containing structure was performed with a confocal laser microscope (LSM5 PASCAL Axioplan2 imaging: manufactured by Carl Zeiss) using a 100 × oil immersion lens (numerical aperture 1.4, Plan-APOCHROMAT). Acquired. As a laser at the time of image acquisition, a wavelength 458 nm argon laser was used. In addition, a refractive index adjusting liquid (Immersol 518F: manufactured by Carl Zeiss) having a refractive index of 1.518 was used for image acquisition.
Scanning in the thickness direction of the carbon nanotube-containing structure was performed from the surface to the interface with the base material, and images of about 11 μm were obtained at a pitch of 0.1 μm. The optical thickness per image under these conditions was about 300 nm.
(Calculation of average value of area ratio [A1] and average value of area ratio [A2])
An extended focus image is created from the slice image acquired by the above method, and carbon nanotubes in the image are extracted by binarization processing using image processing software (Image-Pro PLUS ver 4.5.0: manufactured by Media Cybernetics). Then, the area value and the length of the monodispersed carbon nanotube and the fine aggregate formed by the carbon nanotube in the image were measured. As a result, the total occupied area of the carbon nanotubes in the observation area, the total area of the carbon nanotube fine aggregates having a length of 30 μm or more, and the occupied area of all the carbon nanotubes in the observation image were obtained. And area ratio [A1] was calculated | required by Formula (1) and area ratio [A2] was calculated | required by Formula (2). An analysis was performed on five locations per sample, and the average values of the area ratio [A1] and the area ratio [A2] at these five positions were calculated.

(Analysis of carbon nanotube distribution in the thickness direction)
From the slice image acquired by the above method, an image at a depth of 0.5 μm pitch is selected from the surface, and binary using image processing software (Image-Pro PLUS ver 4.5.0: Media Cybernetics) The carbon nanotubes in the image were extracted by the conversion process, and the area values of the monodispersed carbon nanotubes and the fine aggregates formed by the carbon nanotubes in the image were measured. From the obtained measured values, the area ratio of the carbon nanotubes present in the three layers (surface layer, intermediate layer, and bottom layer) formed when being divided into three equal parts in the thickness direction was calculated. The results are shown in Table 1.

The structures of Examples 1 to 3 in which the average value of the area ratio [A1] was 10% or more and the average value of the area ratio [A2] was 25% were high in conductivity.
However, the carbon nanotube-containing structure of Comparative Example 1 in which the average value of the area ratio [A1] was less than 25% despite being manufactured using the carbon nanotube-containing composition having the same content is conductive. It was low. This is probably because the area ratio [A2] is a component derived from the conductive network structure formed by the carbon nanotubes in the carbon nanotube-containing structure, and the conductive network structure was small.

Since the carbon nanotube-containing structure of the present invention can exhibit the conductivity close to the maximum that can be expressed by the amount of carbon nanotubes contained, various antistatic agents, capacitors, electric double layer capacitors, batteries, fuel cells, The polymer electrolyte membrane, electrode layer, catalyst layer, gas diffusion layer, gas diffusion electrode layer, separator and other members, EMI shield, chemical sensor, display element, nonlinear material, anticorrosive, adhesive, fiber, spinning material, It can be applied to applications such as antistatic coating, anticorrosion coating, electrodeposition coating, plating primer, conductive primer for electrostatic coating, anticorrosion, and improvement of battery storage capacity.
In addition, the composite of the present invention includes industrial packaging materials such as semiconductors and electronic parts, transparent conductive resin plates used in semiconductor manufacturing clean rooms, etc., electrophotographic recording materials such as overhead projector films and slide films, etc. Antistatic film, transparent conductive film, audio tape, video tape, computer tape, magnetic recording tape such as flexible disk, antistatic, LSI wiring of electronic device, electron gun of field emission display (FED) Source), electrode, hydrogen storage agent, transparent touch panel, electroluminescence display, flat panel display such as liquid crystal display and display device surface display protective plate, front plate, antistatic and transparent electrode, transparent electrode film, organic Luminescent materials, buffer materials for forming the recto B luminescence element, an electron transporting material, a hole-transporting material and a fluorescent material, available thermal transfer sheet, transfer sheet, the thermal transfer image-receiving sheet, as the image-receiving sheet.

Claims (5)

A carbon nanotube-containing structure containing a carbon nanotube (a) and a resin (b),
The resin (b) comprises a polymer having a urethane (meth) acrylate compound unit,
The average value of the carbon nanotube area ratio [A1] represented by the following formula (I) is 10% or more, and the average value of the carbon nanotube fine aggregate area ratio [A2] represented by the following formula (II) is 25. %, A carbon nanotube-containing structure characterized by being at least%.
Formula (I): Carbon nanotube area ratio [A1] = [(total occupied area of carbon nanotubes in observation area) / (total observation area)] × 100 (%)
Formula (II): Carbon nanotube fine aggregate area ratio [A2] = [(total area of carbon nanotube fine aggregates having a length of 30 μm or more) / (occupied area of all carbon nanotubes in the observed image)] × 100 ( %)
However, the total occupied area of the carbon nanotubes in the observation area, the total area of the carbon nanotube fine aggregates having a length of 30 μm or more, and the occupied area of all the carbon nanotubes in the observation image are provided with an immersion lens and a confocal optical system. Using the confocal mode of the microscope, the carbon nanotube-containing structure is observed at predetermined intervals in the thickness direction, slice images are obtained, and an extended focus image reconstructed from the slice images is analyzed and obtained. Value. Moreover, area ratio [A1] and area ratio [A2] are calculated | required in three or more places, and the average value of area ratio [A1] is an average value of area ratio [A1] measured in three or more places, and area ratio [ The average value of A2] is the average value of the area ratio [A2] measured at three or more locations.   The carbon nanotube-containing structure according to claim 1, wherein the carbon nanotube-containing structure is in a film form.   The carbon nanotube-containing structure according to claim 2, wherein the carbon nanotube (a) is contained in an area of 45% by area or more in any part when it is divided into three equal parts in the thickness direction.   The composite_body | complex which has the carbon nanotube containing structure of Claim 2 or 3 on the single side | surface or both surfaces of a base material.   The composite according to claim 4 which is a transparent conductive film or a transparent conductive sheet.