JP2009196828A - Manufacturing method of carbon nanotube-containing powder and carbon nanotube-containing powder and carbon nanotube-containing redispersion liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a carbon nanotube-containing powder and to provide the carbon nanotube-containing powder and a carbon nanotube-containing redispersion liquid. <P>SOLUTION: In the manufacturing method of the carbon nanotube-containing powder, a water dispersion is prepared by dispersing the carbon nanotube in water and also dissolving a solid anionic surface active agent (β-naphthalenesulfonic acid formalin condensate sodium salt etc.) at 23°C, thereafter, the water is removed from the water dispersion by a spray drying method. In the other manufacturing method, a mixture of a nonionic surface active agent (polyoxyethylene distyrene phenylether etc.) and a thickener being solid at 23°C (k-carageenan etc.) is used. In the carbon nanotube-containing powder, a part of the carbon nanotube is incorporated at the inside of the particle consisting of a surface active agent etc. and also the other part is projected from the surface of the particle. In the redispersion liquid, the carbon nanotube-containing powder is redispersed in the water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a carbon nanotube-containing powder, a carbon nanotube-containing powder produced by this method, and a carbon nanotube-containing redispersed liquid obtained by redispersing the carbon nanotube-containing powder in water. More specifically, the present invention is a method for producing a carbon nanotube-containing powder in which carbon nanotubes are dispersed in water and a specific surfactant or the like is dissolved, and then water is removed by a spray drying method, and powdered. Carbon nanotube-containing powder produced by this method and having a specific form, and a redispersion liquid obtained by redispersing the carbon nanotube-containing powder in water, the carbon nanotube-containing redispersion liquid containing a larger amount of carbon nanotubes About.

  Substances composed of fine particles such as carbon nanotubes have the property that the particles attract each other by van der Waals force and the like, and the primary particles aggregate to form secondary particles. In addition, carbon materials such as carbon nanotubes are usually hydrophobic and have a property of being difficult to disperse in water. On the other hand, organic materials have good compatibility and are easily mixed, but basically are not soluble. Furthermore, since carbon nanotubes and the like have a strong cohesive force, when they are dispersed in a medium, they are often dispersed in the form of a slurry in the medium, and this improves the dispersibility. It is used in. Moreover, the medium is removed from the slurry-like dispersion by natural drying, hot-air drying, freeze-drying or the like (see, for example, Patent Document 1) and pulverized.

Special table 2004-53442 publication

  However, in the case of a slurry-like dispersion, it is not easy to accurately grasp the solid content concentration due to evaporation or volatilization of the medium. In addition, there is a problem that the slurry-like dispersion cannot be developed for applications that are difficult to use. Therefore, the medium is removed and pulverized for use, but there is a problem that pulverization by natural drying and hot air drying returns to an aggregate before dispersion. Furthermore, in lyophilization, the molecular motion of the carbon nanotube and the surfactant stops during freezing, and a good dispersion state cannot be maintained. Also in Patent Document 1, a water-soluble polymer is blended in an aqueous suspension of carbon nanotubes and pulverized by freeze-drying. However, in freeze-drying, the particle size is not easy to control, In order to achieve this, post-operation such as grinding and sizing is required.

  The present invention has been made in view of the above situation, and a carbon nanotube-containing powder in which carbon nanotubes are dispersed in water in which a specific surfactant or the like is dissolved, and then water is removed by a spray drying method to obtain a powder. And a carbon nanotube-containing powder produced by this method and having a specific form. The present invention also provides a redispersed liquid obtained by redispersing the carbon nanotube-containing powder in water, in which a larger amount of carbon nanotubes are dispersed in a good dispersed state, and the carbon nanotube-containing redispersed liquid is contained. Objective.

The present invention is as follows.
1. Dispersing carbon nanotubes in water and dissolving a solid anionic surfactant at 23 ° C. to prepare an aqueous dispersion, and then removing the water from the aqueous dispersion by a spray drying method A method for producing a carbon nanotube-containing powder.
2. 1. The above anionic surfactant having a phenyl group or a naphthalene group. A method for producing a carbon nanotube-containing powder as described in 1.
3. An aqueous dispersion is prepared by dispersing carbon nanotubes in water and dissolving a mixture of a nonionic surfactant and a solid thickener at 23 ° C., and then, from the aqueous dispersion by a spray drying method. A method for producing a carbon nanotube-containing powder, wherein water is removed.
4). 2. The nonionic surfactant having 3. a phenyl group or a naphthalene group. A method for producing a carbon nanotube-containing powder as described in 1.
5. Above 1. Or 2. The carbon nanotube-containing powder produced by the production method according to claim 1, wherein a part of the carbon nanotube is taken into the particles made of the anionic surfactant, and the other part of the carbon nanotube is the powder. A carbon nanotube-containing powder characterized by protruding from the surface of a particle.
6). 3. above. Or 4. The carbon nanotube-containing powder produced by the production method according to claim 1, wherein a part of the carbon nanotube is taken into the particles composed of the nonionic surfactant and the thickener, and the carbon nanotube A carbon nanotube-containing powder, wherein the other part protrudes from the surface of the particle.
7). 5. above. Or 6. A carbon nanotube-containing redispersed liquid, wherein the carbon nanotube-containing powder described in 1 is redispersed in water.
8). 6. The average particle size of the carbon nanotube-containing powder is 0.2 to 20 μm. A carbon nanotube-containing redispersion liquid as described in 1.
9. 6. The content of the carbon nanotube-containing powder is 8 to 20% by mass. Or 8. A carbon nanotube-containing redispersion liquid as described in 1.

According to the method for producing the carbon nanotube-containing powder of the present invention using an anionic surfactant, and the other method for producing the carbon nanotube-containing powder of the present invention using a nonionic surfactant and a thickener, water is produced by a spray dryer. Is instantly removed and pulverized, so that a carbon nanotube-containing powder in which the dispersion state in the aqueous dispersion is maintained can be obtained. In addition, in a water dispersion, carbon nanotubes usually reaggregate over time, but since the carbon nanotube-containing powder is a solid, unless it comes into contact with water or is exposed to a high humidity atmosphere. A controlled and good dispersion state is maintained.
Further, when the anionic surfactant has a phenyl group or a naphthalene group, and when the nonionic surfactant property has a phenyl group or a naphthalene group, the aggregation of the carbon nanotubes is further suppressed, and a particularly good dispersion state is obtained. It can be set as the carbon nanotube containing powder which has.

The carbon nanotube-containing powder of the present invention produced using an anionic surfactant and the other carbon nanotube-containing powder of the present invention produced using a nonionic surfactant and a thickener are prepared by spray drying. Since the water is instantly removed and manufactured, the carbon nanotubes in the aqueous dispersion are kept in a good dispersion state and become a powder. Aggregation, precipitation, etc. are observed compared to liquids (liquid dispersions). It does not occur easily and has excellent storage and storage. Moreover, since it is a powder, measurement is easy and a predetermined amount of powder can be accurately measured and used. Furthermore, the bulk density can be increased (for example, about 5 times) compared with the case where only carbon nanotubes exist, and the volume can be reduced, which is advantageous in terms of costs such as transportation and inventory. . In addition, carbon nanotubes can be dispersed and contained in a high concentration in a short time and at a low cost in resin molding, urethane foaming process, rubber processing process, reactive paint and reactive adhesive, etc., which become high temperature during processing. . Furthermore, it can be easily dispersed in water only by stirring with a simple stirrer or the like, and since it is in the form of a powder incorporated into a surfactant, no precipitation occurs.
Even when a large shearing force is applied at a high temperature as in resin molding, if the carbon nanotube-containing powder of the present invention in which carbon nanotubes are dispersed in advance is used, the carbon nanotubes can be kept in a good form while maintaining the aspect ratio of the carbon nanotubes. Can be dispersed.

  The carbon nanotube-containing redispersion liquid of the present invention is obtained by redispersing the carbon nanotube-containing powder of the present invention or other present invention in water, and the preparation of this redispersion liquid is extremely easy and should be used in many applications. In particular, it is useful in applications that are difficult to use with solids such as carbon nanotube-containing powders. Moreover, in this redispersion liquid, more carbon nanotubes can be contained. For example, carbon nanotubes can be blended at a high concentration in binders, paints, inks, adhesives, adhesives, and the like. In addition, when the conventional aqueous dispersion is stored as it is, it may not be possible to grasp the exact content of carbon nanotubes during use due to evaporation and volatilization of water. Since the contained powder can be redispersed in water immediately before use, the content of carbon nanotubes can be accurately grasped.

[1] Method for Producing Carbon Nanotube-Containing Powder In the method for producing carbon nanotube-containing powder of the present invention, an aqueous dispersion is obtained by dispersing carbon nanotubes in water and dissolving a solid anionic surfactant at 23 ° C. And then removing water from the aqueous dispersion by spray drying.

In another method for producing a carbon nanotube-containing powder of the present invention, the method of the present invention is used except that a mixture of a nonionic surfactant and a thickener solid at 23 ° C. is used instead of the anionic surfactant. The carbon nanotube-containing powder can be produced in the same manner as described above.
Hereinafter, the term "surfactant" means both an anionic surfactant and a nonionic surfactant.

(1) Preparation of Aqueous Dispersion The “water” is not particularly limited, and for example, distilled water, ion exchange water, tap water and the like can be used.

  The “carbon nanotube” is not particularly limited, and as the carbon nanotube, a carbon nanotube usually used as a conductive material can be used. The carbon nanotubes may be single-walled single-walled carbon nanotubes or multi-walled multi-walled carbon nanotubes. Carbon nanotubes include carbon blacks such as furnace black, acetylene black, and ketjen black, and other carbon-based conductive materials such as carbon nanohorns, carbon nanocoils, and fullerenes, and the total amount of carbon nanotubes is 100% by mass. In this case, it can be used by mixing 50% by mass or less, particularly 30% by mass or less, and further 10% by mass or less, but the total amount is preferably carbon nanotubes.

  The amount of carbon nanotube dispersion is not particularly limited, but when the total amount of water and carbon nanotubes is 100% by mass, 0.5 to 5% by mass, particularly 0.5 to 4% by mass, and further 1 to 3% by mass. It is preferable that If the amount of carbon nanotube dispersion is 0.5 to 5% by mass, the carbon nanotubes are sufficiently uniformly dispersed in water, and the carbon nanotubes are more uniformly dispersed inside the particles made of a surfactant or the like. Thus, a carbon nanotube-containing powder having excellent conductivity and the like can be obtained.

  As the “anionic surfactant”, various anionic surfactants that are solid at 23 ° C. can be used without particular limitation. Examples of the anionic surfactant include fatty acid metal salt or amine salt, carboxylic acid metal salt or amine salt, alkylsulfonate metal salt or amine salt, alkylsulfuric acid metal salt or amine salt, alkylbenzenesulfonic acid metal salt. Alternatively, an amine salt, a metal salt or amine salt of alkylnaphthalene sulfonic acid, a metal salt or amine salt of alkyl phosphoric acid, and the like can be given.

  As the anionic surfactant, an anionic surfactant having a phenyl group or a naphthalene group capable of dispersing carbon nanotubes more easily and sufficiently is preferable. Such anionic surfactants include alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl naphthalene sulfonate formalin polycondensates, polyoxyethylene alkyl phenyl ether sulfates, polyoxyethylene alkyl phenyl ether phosphates. Etc. Only one type of anionic surfactant may be used, or two or more types may be used in combination.

  The amount of the anionic surfactant dissolved is not particularly limited, but when the total amount of water and the anionic surfactant is 100% by mass, it can be 0.5 to 5% by mass, It is preferable that it is 3 mass%, especially 0.5-1.5 mass%, and also 0.8-1.2 mass%. If the dissolved amount of the anionic surfactant is 0.5 to 5% by mass, a part of the carbon nanotubes can be easily taken into the particles made of the anionic surfactant, and the other part is sufficiently from the surface of the particles. A carbon nanotube-containing powder that protrudes and has excellent conductivity and the like can be obtained.

  The “nonionic surfactant” is not particularly limited, and various nonionic surfactants can be used. As this nonionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene alkylphenyl ether, polyoxyethylene polyoxypropylene block copolymer, Examples thereof include polyoxyethylene sorbitan alkyl ester, polyglycerin alkyl ester, alkylamine polyoxyethylene adduct, alkylamine polyoxyethylene polyoxypropylene adduct and the like.

  As the nonionic surfactant, a nonionic surfactant having a phenyl group or a naphthalene group capable of dispersing carbon nanotubes more easily and sufficiently is preferable. Examples of such nonionic surfactants include polyoxyethylene alkylphenyl ether and polyoxyethylene polyoxypropylene alkylphenyl ether. Only one nonionic surfactant may be used, or two or more nonionic surfactants may be used in combination.

  Although the compounding quantity of a nonionic surfactant is not specifically limited, When the sum total of water and a nonionic surfactant is 100 mass%, it can be set to 0.2-5 mass%, 0.2- It is preferable that it is 1.5 mass%, especially 0.2-1 mass%, and also 0.3-0.7 mass%. If the blending amount of the nonionic surfactant is 0.2 to 5% by mass, a part of the carbon nanotubes can be easily taken into the particles made of the nonionic surfactant and the other part is sufficiently from the surface of the particles. And a carbon nanotube-containing powder having excellent conductivity and the like.

  As the “thickener”, various thickeners that are solid at 23 ° C. can be used without particular limitation. Examples of the thickener include gum arabic, gum karaya, xanthan gum, casein, agar, alginic acid, α-cyclodextrin, dextrin, dextran, carrageenan, gelatin, collagen, pectin, starch, chitin and derivatives thereof, chitosan and derivatives thereof, elastin , Heparin, heparinoid, heparin sulfate, heparan sulfate, hyaluronic acid, methylcellulose, hydroxyethylcellulose and other polysaccharides and derivatives thereof, as well as ceramide, macrogol, glycerin, popidone, polyvinyl methacrylate, polyvinyl alcohol, polyacrylic acid, carboxyvinyl polymer And polyethyleneimine. As the thickener, carrageenan, polyvinyl alcohol, and the like are particularly preferable because they are general-purpose products, are low-cost, have good hydrophilicity, and can form a film. Only one type of thickener may be used, or two or more types may be used in combination.

  The amount of the thickener dissolved is not particularly limited. When the total amount of water and the thickener is 100% by mass, 0.005 to 0.025% by mass, particularly 0.005 to 0.02% by mass, Furthermore, it is preferable that it is 0.008-0.015 mass%. If the dissolution amount of the thickener is 0.005 to 0.025% by mass, the nonionic surfactant together with the thickener is easily and sufficiently dissolved in water to obtain a more homogeneous aqueous dispersion. be able to. Further, the mass ratio of the nonionic surfactant and the thickener is not particularly limited, but when the total of the nonionic surfactant and the thickener is 100% by mass, the thickener is 0.5%. It is preferable that it is -3.5 mass%, especially 1-3 mass%, and also 1.5-2.5 mass%. If the mass proportion of the thickener is 0.5 to 3.5 mass%, the nonionic surfactant is easily and sufficiently dissolved in water together with this thickener to obtain a more homogeneous aqueous dispersion. be able to.

A thickening aid can be used in combination with the thickener. As the thickening aid, a metal halide compound can be used. Examples of the metal halide compound include calcium iodide, sodium iodide, potassium iodide, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, barium chloride, sodium bromide, potassium bromide and the like. The mass ratio of the nonionic surfactant and the thickening aid is not particularly limited, but when the total of the nonionic surfactant and the thickening aid is 100% by mass, the thickening aid is 0. It is preferably 1 to 1% by mass, particularly preferably 0.1 to 0.8% by mass, and more preferably 0.2 to 0.6% by mass. If the mass proportion of the thickening aid is 0.1 to 1% by mass, the nonionic surfactant can be easily dissolved in water, and a more homogeneous aqueous dispersion can be obtained.
The thickening agent and the thickening aid can be used in combination in the method for producing a carbon nanotube-containing powder of the present invention using a solid anionic surfactant at 23 ° C.

  In order to improve the dispersion state of carbon nanotubes, etc., in addition to carbon nanotubes, surfactants, etc., water dispersions can be used for general purpose dispersions such as aqueous wetting dispersants used for dispersing pigments, etc. An agent can also be blended. Thereby, carbon nanotubes and the like can be more uniformly dispersed, and the produced carbon nanotube-containing powder can be more easily redispersed in water. This dispersant can be blended in an amount of 0.01 to 1.0 part by mass with 100 parts by mass of water.

  The method for preparing the “aqueous dispersion” is not particularly limited, and water, carbon nanotubes, and a surfactant are put into a stirrer and stirred, mixed, and then the mixture is mixed with an ultrasonic homogenizer, ball mill, bead mill, planetary mill. The carbon nanotubes can be prepared by dispersing them in various pulverizing and / or dispersing machines such as an atomizer. In addition, the thickener and the thickening aid and dispersant used as necessary may be blended in the stirring and mixing step, or may be blended in the dispersing step. Since it can disperse | distribute more efficiently and adhere to the carbon nanotube surface, it is preferable to mix | blend by a dispersion | distribution process.

  Furthermore, when using a thickener and a thickener, water, carbon nanotubes and a surfactant are stirred and mixed, then the mixture is dispersed, and then the thickener is added to continue the dispersion. Thereafter, a preparation method in which a thickening aid is added and dispersion is further continued is more preferable. Thus, by continuing the dispersion process step by step, the carbon nanotubes can be finely dispersed on the surface of the normal temperature solid surfactant. Moreover, when using a dispersing agent, since it is necessary to cover the surface of a carbon nanotube with this dispersing agent, it is preferable to mix | blend in the stage before mixing | blending of a thickener in presence of a water | moisture content.

(2) Powdering by Spray Drying Method The carbon nanotube-containing powder can be produced by removing water from the aqueous dispersion prepared as described in (1) above by the “spray drying method”. The spray dryer used for this spray drying method is not particularly limited, and a general apparatus such as a spray dryer using a cyclone method can be used. In addition, the particle size of the powder can be controlled by the size of the droplets at the time of spraying. The size of these droplets can be changed by changing the nozzle diameter of the spray dryer and by changing the ejection amount (pump flow rate) at the time of spraying. Etc. can be controlled.

  Further, the particle diameter of the carbon nanotube-containing powder is not affected by the size of the carbon nanotube, but is influenced by the mass ratio of the carbon nanotubes taken in per powder particle. Therefore, if carbon nanotubes having a large outer diameter and length are used, in the case of a powder having a large difference in particle diameter, it can be dispersed in a form more similar to primary particles.

[2] Carbon nanotube-containing powder The carbon nanotube-containing powder of the present invention is produced by the method for producing a carbon nanotube-containing powder of the present invention, and a part of the carbon nanotube is taken into the particles made of an anionic surfactant. And the other part of the carbon nanotube protrudes from the surface of the particle.

Another carbon nanotube-containing powder of the present invention is produced by the method of producing another carbon nanotube-containing powder of the present invention, and a part of the carbon nanotube is taken into the particles composed of a nonionic surfactant and a thickener. And the other part of the carbon nanotube protrudes from the surface of the particle.
In the carbon nanotube-containing powder of the present invention and other carbon nanotubes of the present invention, the “carbon nanotube”, the “surfactant” and the “thickening agent” are the same as those of the carbon of the present invention and the other of the present invention. The description about each in the manufacturing method of a nanotube containing powder can be applied as it is.
Moreover, when a thickener, a thickening aid, and a dispersing agent are used at the time of manufacture, these are taken in in the particle | grains or have adhered to the particle | grain surface.

  In the carbon nanotube-containing powder of the present invention and the other present invention, a part of the carbon nanotube is taken into the inside of the particle, and the other part protrudes from the surface of the particle. The protruding other part is an end part or a part of the intermediate part of the carbon nanotube, but is often an end part. Thus, since many carbon nanotubes protrude on the surface of particle | grains, in this carbon nanotube containing powder, the outstanding electroconductivity which a carbon nanotube originally has is expressed.

[3] Re-dispersed liquid The carbon nanotube-containing re-dispersed liquid of the present invention is characterized in that the carbon nanotube-containing powder of the present invention and other present invention are re-dispersed in water.
In addition, about the said "carbon nanotube containing powder" and the above "water", the description about each in the manufacturing method of the carbon nanotube containing powder of the said this invention and another this invention is applicable as it is.

  The average particle diameter of the carbon nanotube-containing powder to be redispersed in water is not particularly limited, but in order to redisperse a larger amount of carbon nanotube-containing powder, it is preferably 0.2 to 20 μm, 0.2 to 15 μm. In particular, the thickness is more preferably 0.5 to 10 μm. The average particle diameter of the carbon nanotube-containing powder can be measured with a particle size distribution meter, a scanning electron microscope, or the like.

  The carbon nanotube-containing powder of the present invention and other present inventions can be redispersed in water at a mass ratio of 0.01 to 20% by mass. In addition, the carbon nanotube-containing powder of the present invention and other present invention can be re-dispersed in a larger amount than the carbon nanotubes dispersed in the aqueous dispersion when the powder is produced, and the carbon nanotube-containing powder in the re-dispersed liquid The content of the powder can be 5 to 20% by mass, preferably 8 to 20% by mass. Thus, since 5-20 mass%, especially 8-20 mass% and a large amount of carbon nanotube-containing powder can be re-dispersed, it is more in a small amount of dispersion compared to the aqueous dispersion used at the time of powder production. The carbon nanotube-containing powder can be transported and handled, and the transport cost can be reduced.

  The redispersion of the carbon nanotube-containing powder in water is very easy, and the redispersion method is not particularly limited. A predetermined amount of the carbon nanotube-containing powder can be weighed and poured into water, and can be easily and sufficiently redispersed by stirring with a simple stirrer such as an electromagnetic stirrer. In addition, since the viscosity increases with an increase in the amount of powder to be redispersed, in that case, it can be redispersed with an ultrasonic stirrer, a high-viscosity homogenizer, or the like.

[1] Production Example 1 of carbon nanotube-containing powder
(1) Preparation of aqueous dispersion Multi-wall carbon nanotube (manufactured by Nanocarbon Technology, average diameter: 50 to 100 nm, average length: 50 μm) 90 g, anionic surfactant (β-naphthalenesulfonic acid formalin condensed sodium salt) 90 g and 2820 g of distilled water were stirred for 30 seconds with a stirrer (manufactured by Primix, model “TK Robotics + TK homomixer Mark II”) and mixed. Thereafter, the mixture was mixed with a bead mill (manufactured by Shinmaru Enterprises, model “DYNO-MILL MULTI LAB”, gap separator system, capacity 1.4 liters, zirconia beads φ: 0.3 mm, filling rate: 80%, peripheral speed: 10 m / Second, flow rate; 40 liters / hour) for 60 minutes to prepare an aqueous dispersion in which 3% by mass of carbon nanotubes are dispersed and contained.

(2) Manufacture of powder From the aqueous dispersion prepared in (1) above, 2000 g of the aqueous dispersion was taken into a spray dryer (manufactured by Nihon Büch, model “BUCHI-B290”) with a suction hose, and set temperature 200 ° C. The powder was removed by removing water under the conditions of a part measurement temperature of 97 ° C., a pump output of 30%, a spray flow of 40 mm, and a required time of 245 minutes to produce 57.6 g (yield: about 96%) of carbon nanotube-containing powder.

Example 2
(1) Preparation of aqueous dispersion 30 g of multi-walled carbon nanotubes (manufactured by Nanocarbon Technology, average diameter: 20-50 nm, length: 50 μm), 15 g of nonionic surfactant (polyethyleneethylene distyrenated phenyl ether) and 2955 g of distilled water was stirred with the same stirrer used in Example 1 for 30 seconds and mixed. Thereafter, the mixture was dispersed for 60 minutes under the same conditions as in Example 1 by the same bead mill used in Example 1. Next, 0.3 g of k-carrageenan was added as a thickener, and the operation was continued for 15 minutes. Thereafter, 0.06 g of calcium iodide was added as a thickening aid, and the operation was further continued for 15 minutes. % Of carbon nanotubes were dispersed and contained therein to prepare an aqueous dispersion.

(2) Production of powder From the aqueous dispersion prepared in (1) above, 2000 g of the aqueous dispersion was taken into the same spray dryer as used in Example 1 by the suction hose, and water was removed under the same conditions as in Example 1. Thus, 28.4 g (yield: about 94%) of carbon nanotube-containing powder was produced.

[2] Electron microscope observation of carbon nanotube-containing powder, etc. (1) Multi-wall carbon nanotube used in Example 1, (2) Carbon nanotube-containing powder of Example 1, (3) Carbon nanotube-containing powder of Example 1 A re-dispersed liquid prepared by stirring water by a simple operation in which water (powder and water is 100% by mass, powder is 12% by mass) is added to a test tube and shaken by hand. The dispersion state of the carbon nanotube-containing powder when it is filtered through a membrane filter and water is removed, and (4) the carbon nanotube-containing powder and water of Example 1 (when the total of the powder and water is 100% by mass) , The powder is 12% by mass) with a homogenizer, and then filtered with a membrane filter to remove the carbon nano tube when water is removed. The dispersion state of the probe was observed with a scanning electron microscope (SEM, manufactured by JEOL Ltd., model “JSM-6390”). 1 to 6 are diagrams based on each electronic data.

  It can be seen that the carbon nanotubes before being dispersed in water are formed into spherical aggregates with a diameter of several tens of μm by aggregation of primary particles as shown in FIG. Further, in the carbon nanotube-containing powder produced in Example 1, as shown in FIGS. 2 and 3, particularly FIG. 3 having a high magnification at the time of SEM observation, surfactant particles having a diameter of several μm and the surface protrude from the surface. Carbon nanotubes are observed. Furthermore, when the carbon nanotube-containing powder produced in Example 1 is redispersed in water, in the case of a simple stirring operation, the same as the carbon nanotube-containing powder before being redispersed, as shown in FIGS. Particles are observed and it can be seen that a good dispersion state is maintained. Further, when sufficiently agitated by a homogenizer, as shown in FIG. 6, the carbon nanotubes are dispersed in a state close to the primary particles, which confirms that the re-dispersed liquid is in a very good dispersion state.

[3] Sedimentation test Into a sample bottle, water and the carbon nanotube-containing powder of Example 2 are charged so that the total amount of the powder and water is 100% by mass, and the carbon nanotube-containing powder is 9% by mass. Then, a person was shaken by a simple operation of shaking the sample bottle by hand to prepare a redispersion liquid. Immediately after preparation of the redispersion, the entire redispersion was black and it was confirmed that the redispersion was sufficiently dispersed. Moreover, when it observed when 1 hour passed and 12 hours passed after stirring, a change in an external appearance was not seen in any case after 1 hour passed and 12 hours passed, and a favorable dispersion state is maintained. I understood that.

  The present invention relates to a water-based, non-aqueous (solvent-based) primer for an electrostatic coating, a resin compound, a general-purpose conductive member, an electromagnetic wave absorber, a lithium battery negative electrode, a resistor, a plating material, a conductive resin, a semiconductor manufacturing article (IC tray) , IC containers, etc.), conveyors, fuel tanks, antistatic paints, clean room interior materials, packaging materials, conductive varnishes, anti-static plates, semiconductor chip heat dissipation substrates, environmental measurement members, acoustic diaphragms for speakers (by sound resonance) (Cutting off residual sound generated), fender mirror (reducing aerodynamic noise generated from fender), toner, conductive ceramics such as conductive zirconia, conductive ceramic coating material, medical device, conductive rubber, electromagnetic wave shield Cloth, electromagnetic shielding glass, electromagnetic shielding fiber, electromagnetic shielding nonwoven fabric, concrete DOO, mortar fiber reinforced cement, fiber-reinforced rubber can be utilized as additives in various technical fields, such as carbon fiber reinforced ceramic.

It is explanatory drawing which observed the aggregate of the carbon nanotube before making it disperse | distribute to water by SEM. It is explanatory drawing which observed the carbon nanotube containing powder manufactured in Example 1 by SEM. It is explanatory drawing at the time of observing carbon nanotube containing powder at a magnification higher than FIG. It is explanatory drawing which observed the carbon nanotube containing powder on a filter by SEM when re-dispersing the carbon nanotube containing powder manufactured in Example 1 in water by simple stirring operation, and filtering with a membrane filter after that. It is explanatory drawing at the time of observing the carbon nanotube containing powder on a filter at a higher magnification than FIG. It is explanatory drawing which observed the carbon nanotube containing powder on a filter by SEM, when the carbon nanotube containing powder manufactured in Example 1 fully stirred with a homogenizer and re-dispersed in water, and was filtered with a membrane filter after that. .

Claims (9)

  Dispersing carbon nanotubes in water and dissolving a solid anionic surfactant at 23 ° C. to prepare an aqueous dispersion, and then removing the water from the aqueous dispersion by a spray drying method A method for producing a carbon nanotube-containing powder.   The method for producing a carbon nanotube-containing powder according to claim 1, wherein the anionic surfactant has a phenyl group or a naphthalene group.   An aqueous dispersion is prepared by dispersing carbon nanotubes in water and dissolving a mixture of a nonionic surfactant and a solid thickener at 23 ° C., and then, from the aqueous dispersion by a spray drying method. A method for producing a carbon nanotube-containing powder, wherein water is removed.   The method for producing a carbon nanotube-containing powder according to claim 3, wherein the nonionic surfactant property has a phenyl group or a naphthalene group. A carbon nanotube-containing powder produced by the production method according to claim 1 or 2,
A carbon nanotube-containing powder, wherein a part of the carbon nanotube is taken into the inside of the particle made of the anionic surfactant, and the other part of the carbon nanotube protrudes from the surface of the particle. A carbon nanotube-containing powder produced by the production method according to claim 3 or 4,
A part of the carbon nanotube is taken into the particle made of the nonionic surfactant and the thickener, and the other part of the carbon nanotube protrudes from the surface of the particle. Carbon nanotube-containing powder.   A carbon nanotube-containing redispersed liquid, wherein the carbon nanotube-containing powder according to claim 5 or 6 is redispersed in water.   The carbon nanotube-containing redispersed liquid according to claim 7, wherein the carbon nanotube-containing powder has an average particle size of 0.2 to 20 μm.   The carbon nanotube-containing redispersed liquid according to claim 7 or 8, wherein the content of the carbon nanotube-containing powder is 8 to 20% by mass.