CN103201026A - Carbon microfiber dispersion liquid - Google Patents

Abstract

Provided is a fine carbon fiber dispersion that uniformly disperses and defibrates aggregated fine carbon fibers having a very high cohesive force in an organic solvent, and forms a stable dispersed state. [Technical means] A fine carbon fiber dispersion liquid in which fine carbon fibers are dispersed in an organic solvent, characterized in that it contains a polymer dispersant represented by the following general formula (1), and the fine carbon fibers contained in the dispersion liquid The size of the aggregates is 5 μm or less.

Description

Fine Carbon Fiber Dispersion

technical field

The present invention relates to a fine carbon fiber dispersion liquid which can disperse and defibrate fine carbon fibers well in an organic solvent and maintain the dispersed and defibrated state stably.

Background technique

The existence of fine carbon fibers whose existence was confirmed about 20 years ago is a tubular material with a diameter of 1 μm or less. In an ideal fine carbon fiber, a tube formed of a sheet (carbon sheet) composed of a 6-membered ring network structure of carbon atoms Parallel to the tube axis, there are also fine carbon fibers in which the tube is formed of double-layer or multi-layer carbon sheets.

Such fine carbon fibers have various properties depending on the number of 6-membered ring network structures composed of carbon atoms and the thickness of the tubes, and various applications can be expected utilizing these properties. For example, using physical properties such as chemical properties, electrical properties, mechanical properties, thermal conductivity properties, and structural properties, it is expected that fine carbon fibers can be used in antistatic components, secondary battery electrode materials, reinforced resin composite materials, radio wave absorbing materials, electrothermal conversion materials, and flat panel displays. Applications in field emission cathode materials, transparent conductive films, thermoelectric conversion element materials, capacitor electrodes, hydrogen storage materials, electrical wiring, heat dissipation materials, solar cell materials and catalyst loading materials.

Trays, carrier tapes, and the like in which fine carbon fibers are added to thermoplastic resins or thermosetting resins are known as antistatic members to which fine carbon fibers are applied. They are used to prevent static electricity generated when handling and transporting semiconductor parts and products. That is, fine carbon fibers exhibit higher electrical conductivity than conventionally used spherical carbon materials such as carbon black, and have a fibrous shape, so adding a small amount can prevent static electricity from occurring, and has the ability to fall off from the matrix resin. It has few advantages and is widely used in anti-static purposes.

In the field of secondary battery electrode materials, it has been proposed to use fine carbon fibers as additives for electrode films.

For example, it has been confirmed that by mixing fine carbon fibers into graphite as a negative electrode active material, the conduction assistance effect and recycling characteristics are improved, and fine carbon fibers are already being used as additives for electrode films of lithium-ion batteries used in mobile phones, personal computers, etc. .

From the above point of view, as an additive for the positive electrode film of high-power, high-capacity secondary batteries used in hybrid vehicles and electric vehicles, by mixing lithium cobalt oxide, lithium iron phosphate, etc., which are active materials for positive electrodes, with fine carbon fibers , so that the conduction assisting effect and the strength of the positive electrode film can be expected to be improved, the density can be increased, and the permeability of the electrode solution can be improved, etc., and its research is ongoing.

In the field of reinforced resin composites, research is under way to further increase rigidity by adding fine carbon fibers to resins together with a mixture of carbon and glass fibers. In addition, studies are underway to add fine carbon fibers to FRP moldings using carbon, glass cloth, or mats to improve surface properties and improve mechanical properties. Furthermore, researches such as adding fine carbon fibers to synthetic fibers to increase the strength of the fibers have been actively conducted.

In the field of electronic equipment manufacturing, it has been studied to apply fine carbon fibers to the fine wiring of integrated circuits (LSI, super LSI, etc.) by inkjet, to manufacture homogeneous field emission cathode sources by screen printing or spraying, and to Applications to flat panel displays and conductive ceramics have been studied, and fine carbon fibers have a larger conductive capacity than metal wiring, so they are also expected to be used in power supply equipment, etc.

In the field of conductive material manufacturing, it is popular to study the use of compression, casting, injection, extrusion or stretching to make anti-static plates using micro-carbon fibers; use conductive coatings to make precision-grade anti-static films, anti-static films or electrostatic coatings. It is suitable for making sub-precision translucent or transparent conductive films by spray coating, spin coating or rod coating.

As mentioned above, the application of fine carbon fibers in various applications as a material with electrical, functional, mechanical and composite effects has been studied. In order to maximize the additive effect, it is necessary to uniformly disperse the fine carbon fibers in water, organic solvents , resin solution, thermosetting resin and thermoplastic resin and other dispersion media.

However, fine carbon fibers are commercially available in such a form that tubular fibers having a diameter of 1 μm or less are intertwined to form aggregates or have a network structure. In addition, such aggregates or network structures may be further aggregated to increase the bulk density and then marketed. Therefore, it is very difficult to disentangle such an aggregate or network structure of fine carbon fibers into individual fibers, or into a state of small aggregates with a size of several nm to tens of nm.

In addition, a very strong cohesive force (van der Waals force) acts between fine carbon fibers disentangled one by one or between aggregates of several nm to tens of nm. Therefore, it is very difficult to disperse the disentangled fine carbon fibers or their aggregates in dispersion media such as water, organic solvents, resin solutions, thermosetting resins, and thermoplastic resins while maintaining their original form. That is, it is because the once-defibrated fine carbon fibers or their aggregates are easily re-agglomerated.

As such, at present, it is difficult to obtain a dispersion liquid of fine carbon fibers in which the fine carbon fibers are sufficiently dispersed in a solvent without agglomeration and whose dispersion state is stable.

In order to solve the above-mentioned problem of dispersibility of fine carbon fibers, the following various proposals have been made so far.

Patent Document 1 discloses a method of vibrating and crushing CNTs (carbon nanotubes) and cyclic organic compounds at a vibration frequency of 5 to 120 s ^-1 to obtain a CNT mixture, and then adding an organic solvent to the CNT mixture to obtain a CNT-containing of the dispersion. In this method, as the cyclic organic compound, a compound soluble in an organic solvent, for example, polyvinylpyrrolidone, polystyrenesulfonate, and polythiophene is used.

Patent Document 2 discloses that a carbon material is dispersed in a hydrocarbon-based solvent to which a basic polymer dispersant is added, an anode is immersed in the solvent, and a voltage is applied to form a carbon material thin film on the surface of the anode. As the basic polymer dispersant, polyester amidoamine salt can be used.

Patent Document 3 discloses a CNT dispersion solution composed of CNTs, an amide-based polar organic solvent, and polyvinylpyrrolidone. As the amide-based polar organic solvent, N-methyl-2-pyrrolidone (NMP) can be used.

Patent Document 4 discloses a carbon fiber dispersion prepared by adding a compound represented by the following general formula as a dispersant for carbon fibers to improve dispersibility when dispersing carbon fibers in an organic solvent solution of an organic solvent-soluble resin.

It is described in Table 1 of Patent Document 4 that in the above formula, R ¹ to R ⁴ are hydrogen atoms, R ⁵ is a propyl group or a hydrogen atom, R ⁶ is a hydrogen atom, R ⁷ is an acetyl group, and x is 75 to 80. value, y is a value from 16 to 20, and z is a value from 0 to 2.

Patent Document 5 discloses that amphiphilic molecules are attached to at least a part of a plurality of CNTs constituting a CNT bundle, and a plurality of CNTs constituting a CNT bundle are isolated and dispersed to produce CNT dispersion by electric attraction between amphiphilic molecules attached to adjacent CNTs. paste.

Patent Document 6 discloses an aqueous dispersion of fine carbon fibers, which is characterized in that, in an aqueous solution containing two kinds of anionic surfactants (A) and (C) and a nonionic surfactant (B), dispersed Micro-fine carbon fibers.

In Patent Documents 1 to 3, anionic surfactants are used for polar organic solvents, and nonionic surfactants are used for nonpolar organic solvents, so that good carbon fiber dispersions can be prepared, but it must be determined according to the type of organic solvent. Use different dispersants. That is, different dispersants (anionic surfactant or nonionic surfactant) must be used when dispersing carbon fibers in a polar organic solvent and when dispersing carbon fibers in a nonpolar organic solvent.

The method of dispersing carbon fibers in an organic solvent disclosed in Patent Document 4 utilizes the viscosity of a resin solution, and the applicable range of the dispersion is limited. In addition, due to the dispersion in a viscous solution, even if you want to increase the degree of dispersion beyond a certain level, the viscosity becomes the main obstacle, and the aggregate size of the finally obtained carbon fibers is only about 20 μm, and it is difficult to disperse to an aggregate size of On the order of 20 μm or less, there is also a problem in the long-term stability of the dispersion. Furthermore, there is a problem that it is necessary to use a resin soluble in an organic solvent.

On the other hand, the fine carbon fiber aqueous dispersion liquids described in Patent Documents 5 and 6 show a good dispersion state and a high degree of completion, so they are beginning to be suitable for various applications, but since the solvent is water, they cannot It is used in dispersion liquids that are affected and cause performance degradation. In addition, it cannot be applied to organic solvents.

As such, at present, although various attempts have been made to disperse fine carbon fibers in organic solvents, sufficient effects cannot always be obtained.

prior art literature

patent documents

Patent Document 1: WO2007/004652

Patent Document 2: JP 2006-63436

Patent Document 3: JP 2005-162877

Patent Document 4: Japanese Patent Laid-Open No. 2008-248412

Patent Document 5: JP 2007-39623

Patent Document 6: WO2010/041750

Contents of the invention

The problem to be solved by the invention

Therefore, the object of the present invention is to obtain a fine carbon fiber dispersion liquid that enables the fine carbon fibers having extremely high cohesive force and forming aggregates to be uniformly dispersed and defibrated in an organic solvent, and the size of the aggregates is suppressed to a minimum. Small, and can maintain a stable dispersed state.

solutions to problems

In order to solve the above-mentioned problems, the inventors conducted intensive studies and found that, in order to disentangle and uniformly disperse aggregates of fine carbon fibers in an organic solvent, a polymer having a chemical structure represented by the following general formula (1) becomes Excellent dispersant for fine carbon fibers, thus completing the present invention.

The present invention provides a fine carbon fiber dispersion, which is a fine carbon fiber dispersion in which fine carbon fibers are dispersed in an organic solvent, characterized in that it contains a polymer dispersant composed of a polymer represented by the following general formula (1) , and the aggregate size of the fine carbon fibers contained in the dispersion is 5 μm or less:

In formula (1),

R ¹ to R ⁴ independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carboxyl group, an acyl group, an amino group, an aryl group, an aryloxy group or a heterocyclic group ,

^R5 and ^R6 independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, an aryl group or a heterocyclic group, ^R5 and ^R6 can also be bonded to each other to form a ring,

R ⁷ represents a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carbonyl group, a carboxyl group, a primary amino group, a secondary amino group, a tertiary amino group, an aryl group, an aryloxy group or a heterocyclic ring base,

All x, y and z are not 0, and on the condition that the value of (4x+2y+2z) representing the number of carbon atoms in the main chain is 400 to 6000 on average, x, y and z are numbers satisfying the following formula:

(x+z)/y=60/40 to 90/10.

Preferably in the present invention,

(1) containing the aforementioned polymer dispersant in an amount of 1 to 200 parts by mass corresponding to 100 parts by mass of fine carbon fibers;

(2) the aforementioned polymer dispersant is shown in the following general formula (2):

In formula (2),

R ⁵ to R ⁷ and x to z are the same as those shown in the aforementioned general formula (1);

(3) the aforementioned polymer dispersant is shown in the following general formula (3):

In formula (3),

R ⁸ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group with 1 to 30 carbon atoms,

^R9 is an alkyl, alkylcarbonyl, aryl, heterocyclic, pyranosyl or furanosyl group with 1 to 30 carbon atoms,

x, y and z are the same as shown in general formula (1);

(4) Also contain anionic surfactant or nonionic surfactant;

(5) As the aforementioned anionic surfactant, a compound represented by the following general formula (4) is contained:

In formula (4),

A is sodium ion, potassium ion or ammonium ion,

B is a number from 1 to 100 on average,

C is a number from 1 to 3;

(6) As the aforementioned nonionic surfactant, a compound represented by any one of the following general formula (5), general formula (6) or general formula (7),

In the aforementioned general formulas (5) to (7),

R ¹⁰ to R ¹⁴ independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a 1-phenyl-ethyl group or a benzyl group,

At least one of R ¹⁰ to R ¹⁴ is not a hydrogen atom,

D is a number from 1 to 100 on average,

E is a number from 1 to 100 on average,

F is a number from 1 to 3,

R ¹⁵ to R ¹⁸ independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, and a 1-phenyl-ethyl group, and at least one of R ¹⁵ to R ¹⁸ is not a hydrogen atom,

G is an average of 10 to 50;

(7) The aforementioned fine carbon fibers have an average outer diameter of 0.5 to 200 nm.

In addition, the fine carbon fiber dispersion liquid of the present invention can be used, for example, as a paste having a viscosity as high as 0.2 to 100 Pa·s (20°C) depending on the application.

For example, the highly viscous fine carbon fiber dispersion (paste) as described above can be used as a paste for lithium ion battery electrodes.

Such paste for lithium ion battery electrodes is preferably,

(8) An electrode active material for the negative electrode or an electrode active material for the positive electrode is added;

(9) The electrode active material for the aforementioned negative electrode is at least one selected from the group consisting of carbon-based active materials, silicon-based active materials and lithium titanate;

(10) The electrode active material for positive electrode is at least one selected from the group consisting of layered rock salt compounds and derivatives thereof, spinel compounds and derivatives thereof, polyanion compounds and derivatives thereof.

By applying the above-mentioned paste for lithium ion battery electrodes to a metal thin film, an electrode conductive film for lithium ion batteries can be obtained, and a lithium ion battery can be formed using this electrode conductive film.

In addition, in the present invention, the size of aggregates of fine carbon fibers is measured in accordance with ASTM D-1210 using a grinding tester (particle size measuring instrument).

The effect of the invention

The fine carbon fiber dispersion liquid of the present invention is characterized by using a polymer represented by general formula (1) as a dispersant for dispersing fine carbon fibers in an organic solvent.

The polymer (polymer dispersant) contains a structural unit having an acetal skeleton and a structural unit having a hydroxyl group in the main chain as can be understood from the general formula (1). Among such structural units, a structural unit having an acetal skeleton has a high affinity to an organic solvent, and a structural unit having a hydroxyl group has a high affinity to fine carbon fibers. That is, such a structural unit is incorporated with a certain balance in a main chain of a certain length (the average number of carbon atoms is 400 to 6000) together with other structural units (structural units having a group R ⁷ ). As a result, in the fine carbon fiber dispersion liquid of the present invention, the above-mentioned dispersant is dispersed in an organic solvent in a state in which the above-mentioned dispersant selectively adheres to the surface of the fine carbon fibers, and the aggregates of the fine carbon fibers are easily defibrated and dispersed by mechanical dispersion treatment, The aggregate size is reduced to a fine size of 5 μm or less, and the state in which fine carbon fibers are uniformly dispersed in an organic solvent can be stably maintained.

Since the fine carbon fiber dispersion liquid of the present invention is stably dispersed with a small size, the fine carbon fiber dispersion can be used in various applications to exhibit the excellent characteristics of the fine carbon fibers. For example, the dispersion, or the dispersion obtained by adding and mixing an organic or inorganic pigment, or a resin for a binder or for dilution can be used as an additive for a paint for forming a conductive coating film or as a coating film forming agent. The coating liquid used is used. Furthermore, what added and mixed the electrode active material to this dispersion liquid can be used effectively as an electrode film formation material, such as a lithium ion battery.

Description of drawings

Fig. 1 is the solid microscope photo (2.8 times) that shows the dispersed state of embodiment 1

Fig. 2 is the optical microscope photo (35 times) that shows the dispersed state of embodiment 1

Fig. 3 is the solid microscope photo (2.8 times) that shows the dispersed state of embodiment 2

Fig. 4 is the optical microscope photo (35 times) that shows the dispersed state of embodiment 2

Fig. 5 is the solid microscope photo (2.8 times) that shows the dispersed state of embodiment 3

Figure 6 is an optical micrograph (35 times) showing the dispersed state of Example 3

Figure 7 is a solid micrograph (2.8 times) showing the dispersed state of Example 4

Figure 8 is an optical micrograph (35 times) showing the dispersed state of Example 4

Figure 9 is a solid micrograph (2.8 times) showing the dispersed state of Example 5

Fig. 10 is an optical microscope photograph (35 times) showing the dispersed state of Example 5

Fig. 11 is a solid micrograph (2.8 times) showing the dispersed state of Example 6

Fig. 12 is an optical microscope photo (35 times) showing the dispersed state of Example 6

Fig. 13 is a solid micrograph (2.8 times) showing the dispersed state of Example 7

Fig. 14 is an optical microscope photo (35 times) showing the dispersed state of Example 7

Figure 15 is a solid micrograph (2.8 times) showing the dispersed state of Example 8

Fig. 16 is an optical micrograph (35 times) showing the dispersed state of Example 8

Figure 17 is a solid micrograph (2.8 times) showing the dispersed state of Example 9

Figure 18 is an optical micrograph (35 times) showing the dispersion state of Example 9

Figure 19 is a solid micrograph (2.8 times) showing the dispersed state of Example 10

Fig. 20 is an optical microscope photograph (35 times) showing the dispersed state of Example 10

Figure 21 is a solid micrograph (2.8 times) showing the dispersed state of Example 11

Figure 22 is an optical micrograph (35 times) showing the dispersion state of Example 11

Figure 23 is a solid micrograph (2.8 times) showing the dispersed state of Example 12

Figure 24 is an optical micrograph (35 times) showing the dispersed state of Example 12

Figure 25 is a solid micrograph (2.8 times) showing the dispersed state of Example 13

Figure 26 is an optical micrograph (35 times) showing the dispersion state of Example 13

Fig. 27 is a solid micrograph (2.8 times) showing the dispersed state of Comparative Example 1

Fig. 28 is an optical microscope photograph (35 times) showing the dispersed state of Comparative Example 1

Fig. 29 is a solid micrograph (2.8 times) showing the dispersed state of Comparative Example 2

Fig. 30 is an optical micrograph (35 times) showing the dispersed state of Comparative Example 2

Fig. 31 is a solid micrograph (2.8 times) showing the dispersed state of Comparative Example 3

Figure 32 is an optical micrograph (35 times) showing the dispersed state of Comparative Example 3

Fig. 33 is a solid micrograph (2.8 times) showing the dispersed state of Comparative Example 4

Fig. 34 is an optical micrograph (35 times) showing the dispersed state of Comparative Example 4

Fig. 35 is a solid micrograph (2.8 times) showing the dispersed state of Comparative Example 5

Fig. 36 is an optical micrograph (35 times) showing the dispersed state of Comparative Example 5

Fig. 37 is an optical micrograph (35 times) showing the dispersed state of Example 2 after standing for 4 months

Figure 38 is an optical micrograph (35 times) showing the dispersed state of Example 2 after standing for 4 months

Figure 39 is an optical micrograph (35 times) showing the dispersed state of Example 4 after 4 months of storage

Figure 40 is an optical micrograph (35 times) showing the dispersed state of Example 4 after 4 months of storage

Figure 41 is an optical microscope photo (35 times) showing the dispersed state of Example 8 after 4 months of storage

Figure 42 is an optical micrograph (35 times) showing the dispersed state of Example 8 after 4 months of storage

Figure 43 is an optical microscope photo (35 times) showing the dispersed state of Example 10 after 4 months of storage

Figure 44 is an optical microscope photo (35 times) showing the dispersed state of Example 10 after 4 months of storage

Fig. 45 is an optical micrograph (35 times) showing the dispersion state after adding the resin component in Example 4

Fig. 46 is an optical micrograph (35 times) showing the dispersion state after adding the resin component in Example 6

Figure 47 is an electron micrograph showing the dispersed state of Example 14 (1000 times)

Figure 48 is an electron micrograph showing the dispersed state of Example 14 (5000 times)

Figure 49 is an electron micrograph showing the dispersed state of Example 14 (10000 times)

Figure 50 is an electron micrograph (1000 times) showing the dispersed state of Example 15

Figure 51 is an electron micrograph (5000 times) showing the dispersed state of Example 15

Figure 52 is an electron micrograph showing the dispersed state of Example 15 (10000 times)

Figure 53 is an electron micrograph showing the dispersed state of Example 16 (1000 times)

Figure 54 is an electron micrograph (5000 times) showing the dispersed state of Example 16

Figure 55 is an electron micrograph showing the dispersed state of Example 16 (10,000 times)

Figure 56 is an electron micrograph showing the dispersed state of Example 17 (1000 times)

Figure 57 is an electron micrograph (5000 times) showing the dispersed state of Example 17

Figure 58 is an electron micrograph showing the dispersed state of Example 17 (10,000 times)

Figure 59 is an electron micrograph showing the dispersed state of Example 18 (1000 times)

Figure 60 is an electron micrograph showing the dispersed state of Example 18 (5000 times)

Figure 61 is an electron micrograph showing the dispersed state of Example 18 (10000 times)

Figure 62 is an electron micrograph (1000 times) showing the dispersed state of Example 19

Figure 63 is an electron micrograph (5000 times) showing the dispersed state of Example 19

Figure 64 is an electron micrograph showing the dispersed state of Example 19 (10,000 times)

Figure 65 is an electron micrograph showing the dispersed state of Example 20 (1000 times)

Figure 66 is an electron micrograph showing the dispersed state of Example 20 (5000 times)

Figure 67 is an electron micrograph showing the dispersed state of Example 20 (10000 times)

Figure 68 is an electron micrograph showing the dispersed state of Example 21 (1000 times)

Figure 69 is an electron micrograph showing the dispersed state of Example 21 (5000 times)

Figure 70 is an electron micrograph showing the dispersed state of Example 21 (10000 times)

Figure 71 is a solid micrograph (1000 times) showing the dispersed state of Comparative Example 6

Figure 72 is an optical micrograph showing the dispersion state of Comparative Example 6 (5000 times)

Figure 73 is a solid micrograph (10000 times) showing the dispersed state of Comparative Example 6

Figure 74 is an optical micrograph (1000 times) showing the dispersed state of Comparative Example 7

Figure 75 is a solid micrograph (5000 times) showing the dispersed state of Comparative Example 7

Figure 76 is an optical micrograph showing the dispersion state of Comparative Example 7 (10000 times)

Figure 77 is a solid micrograph (1000 times) showing the dispersed state of Comparative Example 8

Figure 78 is an optical micrograph showing the dispersion state of Comparative Example 8 (5000 times)

Figure 79 is a solid micrograph (10000 times) showing the dispersed state of Comparative Example 8

Detailed ways

The fine carbon fiber dispersion of the present invention has an aggregate size of the fine carbon fibers in the dispersion of 5 μm or less, and is obtained by adding a polymer dispersant together with the fine carbon fibers in an organic solvent. In addition, in this dispersion liquid, a surfactant may be blended as a dispersion aid for improving dispersibility, and various additives may also be blended according to the application.

＜Polymer dispersant＞

The polymer dispersant added to the fine carbon fiber dispersion liquid of the present invention is composed of a polymer having the following main chain structure as shown in the following general formula (1), and the main chain structure is represented by x, y and z respectively. The number (all not 0) contains a structural unit with an acetal skeleton, a structural unit with a hydroxyl group, and a structural unit with an ^R group.

In the above general formula (1), R ¹ to R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carboxyl group, an acyl group, an amino group, an aryl group , aryloxy or heterocyclyl.

Each of the above-mentioned groups may have a substituent, for example, the above-mentioned amino group may be a mono-substituted amino group or a di-substituted amino group.

R ⁵ and R ⁶ independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an aryl group or a heterocyclic group, and R ⁵ and R ⁶ may be bonded to each other to form a ring. In addition, the above-mentioned groups may have a substituent.

R ⁷ represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carbonyl group, a carboxyl group, an amino group, an aryl group, an aryloxy group or a heterocyclic group.

Each of the above-mentioned groups may have a substituent, for example, the above-mentioned amino group may be a mono-substituted amino group or a di-substituted amino group.

In the above general formula (1), x, y and z are all other than 0, the value of (4x+2y+2z), that is, the number of carbon atoms in the main chain is 400-6000 on average. Furthermore, x, y and z must satisfy the following formula:

(x+z)/y=60/40 to 90/10.

That is, in the main chain of the above-mentioned length, each of the above-mentioned structural units exists in a balance defined by the above-mentioned formula, so that the above-mentioned polymer functions effectively as a dispersant for dispersing fine carbon fibers in an organic solvent.

In addition, in the above general formula (1), it is preferable that R ¹ to R ⁴ are all hydrogen atoms. Specifically, in the present invention, it is preferable to use a polymer represented by the following general formula (2) as a polymer dispersant.

In the above general formula (2), R ⁵ to R ⁷ and x to z are the same as those shown in the above general formula (1).

Furthermore, in the above-mentioned general formula (2), a polymer represented by the following general formula (3) is most preferably used as a polymer dispersant.

In the above general formula (3), x~z are the same as those shown in the above general formula (1), and R ⁸ is the same as the group R ⁵ (or R ⁶ ) in the general formula (1) or (2).

In addition, ^R9 is an alkyl group having 1 to 30 carbon atoms, an alkylcarbonyl group, an aryl group, a heterocyclic group, a pyranosyl group or a furanosyl group. These groups may also have a substituent.

The polymers represented by the above general formulas (1) to (3) can be, for example, polyvinyl alcohol (or copolymers such as polyvinyl vinyl alcohol) obtained by saponifying polyvinyl acetate (or copolymers such as polyvinyl acetate). ) obtained by reacting with aldehydes or ketones. That is, the structural unit bonded with the group R in the general formula ( ¹ ) comes from the unsaponifiable unit when the vinyl acetate unit is saponified into a vinyl alcohol unit or from the introduction of polyacetic acid by copolymerization to the vinyl group. Structural unit in vinyl esters.

In the aforementioned general formulas (1) to (3), when the x value becomes larger, or when the R ⁷ or OR ⁹ group is an acetyl group, when the z value becomes larger, the acetal group or the acetyl group increases, so in non- Increased solubility in polar organic solvents. On the other hand, as the value of y increases, the number of hydroxyl groups increases, so the solubility in polar organic solvents is mainly improved. Generally, when the x value is in a certain range, the solubility of the dispersant in the range of 10 to 25 in the nonpolar organic solvent is improved, and the above-mentioned dispersant in the range of 25 to 40 is extremely Solubility in organic solvents is improved.

In addition, the values of x, y, and z in the aforementioned general formulas (1) to (3) are related to the physical properties of the fine carbon fiber dispersion liquid and the characteristics of various substrates used according to the application of the dispersion liquid. For example, the value of x has a great relationship with the softening property of the coating film (solid content) formed by the dispersion liquid, water resistance, the compatibility of the dispersion liquid with other components, etc., and the value of y has a great relationship with the coating film (solid content) formed by the dispersion liquid. The adhesion of the coating film to various substrates, the hydrophilicity of the coating film or the reactivity with the thermosetting resin is related. In addition, the value of z tends to be related to the glass transition temperature and the viscosity of the fine carbon fiber dispersion liquid.

Furthermore, the average number of carbon atoms (4x+2y+2z) of the main chain of the chemical structure of the above-mentioned dispersant represented by the aforementioned general formulas (1) to (3) is 400 to 6000, preferably 500 to 5000, more preferably 600 to 4000 scope. When the average number of carbon atoms in the main chain is less than 400, the dispersion stability of the fine carbon fibers is poor, and when it exceeds 6000, the solubility in organic solvents may be lacking.

In the present invention, polymers most preferably used as polymer dispersants, that is, polymers represented by the general formula (3) are commercially available.

For example, S-LEC B (R ⁸ =C ₃ H ₇ , R ⁹ =COCH ₃ ) manufactured by Sekisui Chemical Co., Ltd. and denka butyral (R 8 =CH 3 H 7 , R ⁸ =CH ₃ H ₇ , R ⁹ =COCH ₃ ) are commercially available under the brand name of COCH 3 ), and the following ones are preferably used.

S-LEC B manufactured by Sekisui Chemical Co., Ltd.:

Denkabutyral made by DENKI KAGAKU KOGYO KABUSHIKI KAISHA:

In the fine carbon fiber dispersion of the present invention, the polymer dispersant is added in an amount of 1 to 200 parts by mass, preferably 4 to 150 parts by mass, more preferably 5 to 100 parts by mass, per 100 parts by mass of the fine carbon fibers better. If the addition amount of the polymer dispersant in the fine carbon fiber dispersion is too small, the dispersing function of the polymer dispersant cannot be fully exerted, and it may be difficult to suppress the size of the fine carbon fiber aggregates to a size below 5 μm. In addition, the organic solvent The dispersion stability of fine carbon fibers tends to decrease. Furthermore, when the polymer dispersant is added in a larger amount than necessary, the characteristics (such as electrical conductivity) specific to fine carbon fibers are impaired, and the use of the dispersion liquid is limited.

＜Fine Carbon Fiber＞

In the present invention, those known per se can be used as the fine carbon fibers. For example, any one of single-layer, double-layer, and multi-layer fine carbon fibers can be selected and used according to the use of the dispersion. In many applications, it is preferable to use multiple layers of fine carbon fibers.

The average outer diameter of single-layer, double-layer or multi-layer fine carbon fibers obtained by various methods as described above is generally 0.5 to 200 nm, and is obtained in the form of an aggregate having a circle-equivalent diameter of about several cm. Fibers or aggregates pulverized to a circle-equivalent average diameter of about 50 to 100 μm are dispersed in an organic solvent using the aforementioned polymer dispersant to prepare the dispersion liquid of the present invention.

The concentration of the fine carbon fibers in the fine carbon fiber dispersion liquid of the present invention is preferably in the range of 0.01 to 30 parts by mass, preferably 0.2 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, relative to 100 parts by mass of the organic solvent described later. . If the concentration of the fine carbon fibers is too low, it will be difficult to fully exhibit the characteristics (for example, electrical conductivity) specific to the fine carbon fibers. In addition, when the concentration of the fine carbon fibers is too high, it becomes difficult to stably maintain the dispersed state.

＜Organic solvent＞

The organic solvent for dispersing the fine carbon fibers is not particularly limited, and those known per se can be used. In general, the following are preferably used.

Alcoholic solvents:

Methanol, Ethanol, Isopropanol, Butanol, Cyclohexanol, Ethylene Glycol, Propylene Glycol, Diethylene Glycol, Polyethylene Glycol, Polypropylene Glycol, Diethylene Glycol Monoethyl Ether, Polypropylene Glycol Monoethyl Ether, Polyethylene Glycol Monoallyl Ether, Polypropylene Glycol Monoallyl Ether, Ethyl Cellosolve, Butyl Cellosolve, Carbitol, Butyl Carbitol, Methoxybutanol

Ketone solvents:

Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone

Ester solvents:

Ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, methoxybutyl acetate, polyethylene glycol monomethyl ether acetate , polyethylene glycol monoethyl ether acetate

Ether solvents:

Tetrahydrofuran, Dioxane, Dimethyl Sulfoxide

Aliphatic hydrocarbon solvents:

Mineral spirit, alicyclic hydrocarbon solvents are turpentine, mixed hydrocarbon solvents are HAWS, solvent100, solvent150

Aromatic hydrocarbon solvents:

Toluene, xylene, ethylbenzene, vinylbenzene

Halogenated hydrocarbon solvents:

Chlorobenzene, dichlorobenzene, chloroform, bromobenzene, fluorides

Silicone oil solvent:

Polydimethylsiloxane, partially octyl-substituted polydimethylsiloxane, partially phenyl-substituted polydimethylsiloxane

Amine-based organic solvents:

N,N-Dimethylformamide, N-methyl-2-pyrrolidone

＜Surfactant＞

In the fine carbon fiber dispersion liquid of the present invention, a surfactant can be used as a dispersing aid, thereby maintaining the dispersed state of the fine carbon fiber more stably, for example, effectively suppressing the reaggregation of the fine carbon fiber, and dissolving the fine carbon fiber in the dispersion liquid. The use of such surfactants is more effective in that the size of the carbon fiber aggregates is continuously maintained below 5 μm in size.

As such a surfactant, an anionic surfactant or a nonionic surfactant is preferable.

1. Anionic surfactant:

Examples of the anionic surfactant used in the dispersion liquid for fine carbon fibers of the present invention include the following.

Polyoxyethylene alkyl ether sulfate and its derivatives

Polyoxyethylene phenyl ether sulfate and its derivatives

Polycarboxylates and their derivatives

Formalin Condensate of Naphthalene Sulfonate and Its Derivatives

Naphthalene sulfonate and its derivatives

Polyoxyethylene alkyl ether phosphate

Alkyl Sulfate and Its Derivatives

Thiosuccinate and its derivatives

Amide ether sulfate and its derivatives

Taurine Derivatives

Sarcosine derivatives

Arylsulfonates and their derivatives

reactive surfactant

fatty acid salt

Alkenyl succinates and their derivatives

Polystyrene sulfonate and its derivatives

In addition, among the anionic surfactants listed above, the following are preferable.

Polyoxyethylene alkyl ether sulfate and its derivatives

Polyoxyethylene phenyl ether sulfate and its derivatives

Polycarboxylates and their derivatives

Formalin Condensate of Naphthalene Sulfonate and Its Derivatives

Naphthalene sulfonate and its derivatives

Furthermore, among the anionic surfactants listed above, polyoxyethylene phenyl ether sulfate and derivatives thereof are most preferable.

In the present invention, polyoxyethylene phenyl ether sulfate and derivatives thereof most preferably used as anionic surfactants are represented by the following general formula (4).

In general formula (4), A is sodium ion, potassium ion or ammonium ion.

In addition, B represents the number of moles of ethylene oxide (EO) groups, and is 1-100 on average, preferably 3-50, and most preferably 4-40.

Furthermore, C represents the number of substituents bonded to the phenyl group, and is a number of 1-3.

In the present invention, polyoxyethylene phenyl ether sulfate and its derivatives most preferably used as the anionic surfactant are commercially available, for example, under the following trade names.

Homogenol (manufactured by Kao Corporation):

L-18

L-1820

SORPOL (manufactured by TOHO CHEMICAL INDUSTRY Co., Ltd.):

T-10SPG (B=9, C=3)

T-15SPG (B=14, C=3)

7290P (B=14, C=3)

T-20SPG (B=19, C=3)

7953 (B=14, C=3)

7917B (B=19, C=3)

7948 (B=33, C=3)

7556 (B=12, C=2)

HITENOL (manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd.):

NF-08 (B＝8、C＝1～3)

NF-0825 (B＝8、C＝1～3)

NF-13 (B＝13、C＝1～3)

NF-17 (B=25, C=1～3)

2. Nonionic surfactants:

Examples of the nonionic surfactant used in the dispersion liquid for fine carbon fibers of the present invention include the following.

Polyoxyethylene alkyl ether and its derivatives

Polyoxyethylene phenyl ether and its derivatives

Formalin Condensate of Polyoxyethylene Phenyl Ether and Its Derivatives

Polyoxyalkylene Derivatives

alkanolamide type

polyethylene glycol fatty acid ester

Glycerides

P.O.E. Glycerides

Polyoxyethylene sorbitan fatty acid ester

Sorbitan Fatty Acid Ester

Polyoxyethylene sorbitan fatty acid ester

Glycerin Fatty Acid Ester

polyoxyethylene fatty acid ester

Polyoxyethylene Hydrogenated Castor Oil

polyoxyethylene alkylamine

Alkyl alkanolamides

polyethylene glycol

Among the nonionic surfactants listed above, the following are preferably used.

Polyoxyethylene phenyl ether and its derivatives

Formalin Condensate of Polyoxyethylene Phenyl Ether and Its Derivatives

In addition, among the above-mentioned nonionic surfactants, those having a relatively long polyoxyethylene chain in the molecule are preferable.

In the present invention, polyoxyethylene phenyl ethers and derivatives thereof particularly preferred as nonionic surfactants include those represented by the following general formulas (5) and (6). Formalin condensates of base ethers and derivatives thereof include those represented by the following general formula (7).

Polyoxyethylene phenyl ether and its derivatives:

In the aforementioned general formulas (5) and (6),

R ¹⁰ to R ¹⁴ independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a 1-phenyl-ethyl group or a benzyl group,

At least one of R ¹⁰ to R ¹⁴ is not a hydrogen atom,

D and E are numbers of 1-100 on average, respectively, Preferably they are 3-50, More preferably, they are 4-40.

F is a number of 1-3.

The polyoxyethylene phenyl ether represented by the above general formula (5) or (6) and its derivatives are commercially available, for example, under the following trade names.

SORPOL (manufactured by TOHO CHEMICAL INDUSTRY Co., Ltd.):

T-10 (F＝3、E＝9)

T-15 (F=3, E=14)

T-20 (F=3, E=19)

T-26 (F=3, E=24)

T-32 (F＝3、E＝30)

T-18D (F=2, E=12)

EMULGEN (manufactured by Kao Corporation):

A-60 (F=2, E=15)

A-90 (F=2, E=20)

A-500 (F=2, E=50)

B-66 (F＝3)

NOIGEN (manufactured by Dai-Ichi Kogyo Seiyaku Co., Ltd.):

EA-87 (F=1～3, E=8)

EA-137 (F=1～3, E=13)

EA-157 (F=1～3, E=15)

EA-167 (F=1～3, E=17)

EA-177 (F=1～3, E=20)

EA-197D (F=1～3, E=50)

EA-207D (F=1～3, E=100)

Formalin Condensate of Polyoxyethylene Phenyl Ether:

In the aforementioned general formula (7),

R ¹⁵ to R ¹⁸ each independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, and a 1-phenyl-ethyl group (most preferably a 1-phenylethyl group),

At least one of R ¹⁵ to R ¹⁸ is not a hydrogen atom,

G is 10-50 on average, Preferably it is 15-45, More preferably, it is a number of 20-40.

The formalin condensate of polyoxyethylene phenyl ether represented by the general formula (7) and its derivatives are commercially available, for example, under the following trade names.

SORPOL (manufactured by TOHO CHEMICAL INDUSTRY Co., Ltd.):

F-15 (G=21, R ¹⁵ ~ R ¹⁸ = 1-phenyl-ethyl)

F-19 (G=26, R ¹⁵ ~ R ¹⁸ = 1-phenyl-ethyl)

F-24 (G=34, R ¹⁵ ~ R ¹⁸ = 1-phenyl-ethyl)

F-27 (G=38, R ¹⁵ ~ R ¹⁸ = 1-phenyl-ethyl)

In the present invention, the above-mentioned anionic surfactant or nonionic surfactant is usually preferably 5 to 100 parts by mass, particularly 10 to 60 parts by mass, most preferably 20 to 50 parts by mass, relative to 100 parts by mass of fine carbon fibers. The amount used is better. If these surfactants are used in small amounts, the dispersion assisting effect of the surfactants cannot be fully exerted. In addition, if they are used in excess of the necessary amount, a micelle structure will be formed between the surfactants, so it cannot be expected that the amount of Consistent dispersion effects can only lead to economic disadvantages.

＜Other additives＞

As long as the dispersibility and dispersion stability of the fine carbon fibers are not impaired, various additives may be appropriately blended in the fine carbon fiber dispersion of the present invention depending on the application or the like.

Examples of such additives include inorganic pigments, organic pigments, whiskers as fillers, sodium carboxymethylcellulose as a thickener, anti-settling agents, UV inhibitors, wetting agents, emulsifiers, anti-peeling agents, agent, anti-polymerization agent, anti-sagging agent, defoaming agent, anti-floating agent, leveling agent, desiccant, curing agent, curing accelerator, plasticizer, fire-resistant and preventive agent, anti-mildew and anti-algae agent, Antibacterial agent, insecticide, marine antifouling agent, metal surface treatment agent, rust remover, degreasing agent, chemical conversion film agent, bleaching agent, coloring agent, wood sealer (wood sealer), filler (filler), blending agent Sanding sealer, sealer, cement filler or cement paste with resin, etc.

In particular, when using the fine carbon fiber dispersion of the present invention as an additive for paint to impart conductivity to a coating film formed of the paint, for example, inorganic pigments, organic pigments, etc. may be added to the dispersion in advance. In addition, a resin or the like used as a binder (or a diluent for adjusting resistance) may be added. Examples of such resins include the following, and these can also be added in the form of a resin solution dissolved in an organic solvent.

Fats (soybean oil, linseed oil, safflower oil, castor oil) or their derivatives

Natural resins (rosin, copal, shellac) or their derivatives

Processing resin (chroman resin, petroleum resin) or its derivatives

Synthetic resins (alkyd resins (mono-oil alkyd, medium-oil alkyd, long-oil alkyd, phthalic alkyd) or their derivatives

Modified alkyd resin (modified phenolic resin, styrenated resin) or its derivatives

Amino alkyd resin or its derivatives

Oil-free alkyd resin or its derivatives

Acrylic resin (for printing, painting, acrylic polyol, emulsion) or its derivatives

Polystyrene resin or its derivatives

Polyester resin or its derivatives

Urea melamine resin (butylated melamine resin, methylated melamine resin) or its derivatives

Melamine resin or its derivatives

Phenolic resin (phenolic modified maleic acid resin, natural resin modified, phenolic modified pentaerythritol resin) or its derivatives

Polyurethane resin or its derivatives,

Polyamide resin or its derivatives

Polyimide resin precursor (polyamic acid) or its derivatives

Polyetherimide resin precursor or its derivatives

Alcohol-soluble phenolic resin or its derivatives

Epoxy resin or its derivatives

Fluororesin (polyvinylidene fluoride) or its derivatives

Chlorinated polyolefin resin (chlorinated polyethylene resin, chlorinated polypropylene resin, chlorinated ethylene-propylene copolymer, chlorinated ethylene-vinyl acetate copolymer) or its derivatives

Silicone resin or its derivatives

Rubber derivatives (chlorinated rubber, cyclized rubber) or their derivatives

Cellulose derivatives (nitrocellulose, acetylcellulose) or their derivatives

In addition, the fine carbon fiber dispersion liquid of the present invention is preferably used in the formation of lithium-ion battery electrodes, and such substances used in electrode formation are generally formed so that their viscosity (20° C.) is In the paste in the range of 0.2 to 100 Pa·s, an electrode active material (active material for negative electrode or active material for positive electrode) may be added as an additive in general.

Examples of such negative electrode active materials include carbon-based negative electrode active materials, tin-based negative electrode active materials, silicon-based negative electrode active materials, and lithium titanate. Specific examples thereof include the following.

Active material for carbon-based negative electrode:

Artificial graphite, easily graphitizable carbon, non-graphitizable carbon, etc.

Active material for tin-based negative electrode:

Tin alloy materials: copper-tin, iron-tin, silver-tin alloys, etc.

Tin-based oxides: SnMxOy (M=B, P, Al,

Sn:B:P:Al＝1.0:0.6:0.4:0.4)

Tin-based amorphous: a substance obtained by uniformly mixing multiple elements such as tin-cobalt-carbon at the atomic level and making them amorphous.

Active material for silicon-based negative electrode:

Silicon-based alloys such as Li44Si.

Lithium titanate:

LiTiO ₂ (112 phase), LiTi ₂ O ₄ (124 phase),

Li ₄ TiO ₄ (phase 414), Li ₂ TiO ₃ (phase 213),

Li ₄ Ti ₅ O ₁₂ (4512 phase), Li ₂ Ti ₃ O ₇ (237 phase), etc.

Examples of the positive electrode active material include layered rock salt compounds and derivatives thereof, spinel compounds and derivatives thereof, polyanion compounds and derivatives thereof, and specific examples thereof include the following.

Layered rock salt compounds and their derivatives:

LiCoO ₂ , LiNiO ₂ , LiCrO ₂ , LiMnO ₂ ,

LiFeO ₂ , LiTiO ₂ , LiNi _0.5 Mn _0.5 O ₂ ,

LiNi _1/3 Co _1/3 O ₂

Spinel-type compounds and their derivatives:

LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ , LiNiVO ₄ ,

LiCoVO ₄ , LiCoVO ₄ , LiMnVO ₄

Polyanionic compounds and their derivatives:

LiFePO ₄ , LiMnPO ₄ , LiCoPO ₄ ,

LiNiPO ₄ , Li ₂ FeSiO ₄

Furthermore, in the above-mentioned paste, as a conductive auxiliary material, for example, carbon black, acetylene black, Ketjen black, etc. can also be added, and further, as a binder component, for example, a fluororesin (polyvinylidene fluoride (PVDF), PTFE, FKM) or its derivatives, polyimide resin precursor (polyamic acid) or its derivatives, SBR, NBR, BR, PAN, EVOH, EPDM, polyurethane, polyacrylic acid, polyamide, polyacrylate, Polyvinyl ether or its derivatives.

Examples of the electrolytic layer used in the manufacture of lithium-ion batteries include organic electrolytic solutions (electrolytes: LiPF ₆ , LiClO ₄ , LiBF ₄ , LiN(CF ₂ SO ₂ ) ₂ , LiN(C ₂ F ₄ SO ₂ ) ₂ , PC-LiBOB, etc., electrolyte: ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) alone or mixed solution), solid electrolyte (including Composite materials of polymers such as polyethylene oxide or polypropylene oxide and electrolyte salts, polymer gel electrolytes), ionic liquids (ethylmethylimidazolium cation (EMI) salts, etc.), etc.

Separators used in the manufacture of lithium-ion batteries include, for example, polyethylene microporous membranes. The porosity varies depending on the production method, and examples include dry one-component systems, wet two-component systems, and wet three-component systems.

The shape of the lithium ion battery includes a coin cell, a half coin cell, a laminated cell, a cylindrical type, a box type, and the like.

＜Preparation of fine carbon fiber dispersion＞

The fine carbon fiber dispersion liquid of the present invention can be prepared by adding the aforementioned polymer dispersant, fine carbon fibers, and optionally a surfactant or other additives. In this case, the order of adding each agent to the organic solvent is not particularly limited. In order to reliably obtain a fine carbon fiber dispersion in a good dispersed state, it is preferable to add the polymer dispersant and the surfactant added as needed. A method of adding fine carbon fibers to an organic solvent. In particular, in order to achieve good dispersion of fine carbon fibers, it is most preferable to add a polymer dispersant to an organic solvent and then add the fine carbon fibers after dissolving it.

In addition, for various additives added as needed, it is preferable to add the above-mentioned additives after adding a polymer dispersant and a surfactant to an organic solvent, followed by adding fine carbon fibers for dispersion treatment to prepare a fine carbon fiber dispersion liquid. It is preferable to add desired various additives after fully defibrating and dispersing aggregates of fine carbon fibers in advance. If various additives are added before defibrating and dispersing the aggregates, the defibrating and dispersing of the aggregates will become difficult. Sufficiently, aggregates larger than 5 μm may remain.

In addition, the dispersion treatment after adding the polymer dispersant, optionally a surfactant, and fine carbon fibers to the organic solvent can be performed using a normal disperser. For example, bead mill disperser (Dinomill, manufactured by Shimaru Enterprises Corporation), TK LABO DISPER, TK FILMICS, TK PIPELINE MIXER, TK HOMOMIC LINE MILL, TK HOMOJETTER, TK UNI MIXER, TK HOMOMIC LINE FLOW, TK AGIHOMO DISPER (above Homogenizer POLYTRON (manufactured by Chuo Science Trading Co., Ltd.), Homogenizer HISTRON (manufactured by NISSEI Corporation.), BIO MIXER (manufactured by NISSEI Corporation.), turbo mixer (Kodaira Seisakusho Co., Ltd. , Ltd.), Ul Tra Disperser (manufactured by Asada Iron Works Co., Ltd.), Ebara Milder (manufactured by EBARA Corporation), ultrasonic device or ultrasonic cleaner (manufactured by ASONE Corporation), etc.

The conditions of the equipment and the like when performing the dispersion treatment of the present invention using these equipment may be appropriately set according to the desired dispersion state of the fine carbon fibers.

In addition, after once dispersing the fine carbon fibers, it is also possible to appropriately post-add an organic solvent for dilution.

＜Preparation of fine carbon fiber paste＞

Among the above-mentioned fine carbon fiber dispersions, especially pastes used for forming electrode films of lithium-ion batteries, it is necessary that the viscosity (20° C.) is in the range of 0.2 to 100 Pa·s as already described.

The preparation method of such a fine carbon fiber paste is shown below, but it is not limited to these.

As a preparation method of the fine carbon fiber paste of the present invention, for example, the active material for electrodes, the conductive auxiliary material, the fine carbon fiber dispersion liquid of the present invention, and the binder solution are mixed and stirred, and the solid content is adjusted in the range of 20 to 90%. The organic solvent (N-methyl-2-pyrrolidone) was added to increase the concentration. A method of preparing these mixtures with a disperser FILMICS manufactured by PRIMIX Corporation can be mentioned.

In addition, active materials for electrodes, conductive auxiliary materials, and a small amount of binder solution are added to a fine carbon fiber dispersion composed of fine carbon fibers, a polymer dispersant, an organic solvent, and a surfactant, and a planetary mixer (planetary mixer), PD After mixing with a planetary motion disperser such as a PD mixer or a three-arm planetary mixer (TRIMIX), add the remaining amount of binder solution and organic solvent ( N-methyl-2-pyrrolidone) for final mixing to prepare a fine carbon fiber paste.

＜Formation of conductive coating＞

As already described, for the fine carbon fiber dispersion liquid of the present invention, the fine carbon fibers are stably and finely dispersed, so it can be used as a composition for preparing coatings and pastes, for example, organic or inorganic pigments, electrodes can be added The active material and the resin component used as the binder prepare the coating material and fine carbon fiber paste for forming the conductive film.

As a method of forming a conductive film or an electrode conductive film for a lithium-ion battery using such a paint and a fine carbon fiber paste, for example, air spray coating, airless spray coating, low-pressure atomization spray coating, and bar coating can be used. Coating, coating using a spin coater or a dip coater, and formation of a conductive film for lithium ion batteries are performed continuously or discontinuously by a common method such as an applicator.

Drying after coating varies depending on the organic solvent and the type of resin used as a binder. Generally, the drying is performed at a temperature of 10 to 300°C, preferably 60 to 250°C, and more preferably 70 to 200°C. Do it for the right amount of time. If the temperature is too low, drying may not proceed sufficiently, and if the temperature is too high, deformation of the substrate on which the coating film is formed, yellowing of the coating film, and reduction in film properties may be caused. When the water content is strictly controlled as in the electrode film for lithium ion batteries, after the drying step, drying under reduced pressure may be carried out in the range of 150 to 250°C.

In addition, the thickness of the coating film is not particularly limited, but generally, it is 0.01 to 5 mm, particularly 0.1 to 4 mm, particularly preferably 1 to 3 mm (dry film thickness).

Examples of substrates on which the coating film is formed include glass, resin, metals such as copper foil and aluminum foil, and examples of shapes include various shapes such as films, sheets, plates, and three-dimensional moldings.

Example

In the following experiments, the dispersion state and viscosity of the fine carbon fiber dispersion liquid and the surface resistance of the coating film formed using the dispersion liquid were evaluated or measured by the following methods.

<Observation of fine carbon fiber dispersion state in fine carbon fiber dispersion>

Add 20 g of organic solvents to 2 drops of the fine carbon fiber dispersions of Examples 1 to 13 and Comparative Examples 1 to 5, after dilution and stirring, use a solid microscope to observe macroscopically (magnification 2.8 times; objective lens 1 time, zoom magnification 4 times, digital The variable magnification of the camera is 0.7), and microscopic observation is carried out using an optical microscope (magnification of 35 times; objective lens is 50 times, and the variable magnification of the digital camera is 0.7) for evaluation.

In addition, the aggregate size was measured using a Grind Meter (manufactured by Ohira Chemical Industry Co., Ltd.). When the aggregate size was 5 μm or less, the dispersed state was evaluated as ○, and when the aggregate size was greater than 5 μm, the dispersed state was evaluated as ○. Evaluation was x.

＜Observation of fine carbon fiber dispersion state in fine carbon fiber paste＞

5 g of the fine carbon fiber paste was dropped onto the metal thin film, applied with an applicator, and then dried at 120° C. for 10 minutes. Electron microscope observation (magnifications of 1000 times, 5000 times and 10000 times) of the obtained conductive film was performed to evaluate the dispersion state of the fine carbon fibers.

＜Viscosity measurement of fine carbon fiber dispersion＞

The viscosity of the fine carbon fiber dispersion was measured at 20°C using a rotational viscometer (MODEL RE100L, manufactured by Toki Sangyo Co., Ltd.).

＜Viscosity measurement of fine carbon fiber paste＞

The viscosity of the fine carbon fiber paste was measured at 25° C. using a SV-type viscometer (SV-10 manufactured by A&D Company).

<Surface resistance value of fine carbon fiber film>

The fine carbon dispersion was placed in a Petri dish (5 cm in diameter), and the organic solvent was evaporated in a dryer at 120°C. Thereafter, the petri dish was further left in a dryer at 120° C. for 5 hours to produce a fine carbon fiber membrane. The surface resistance value (Ω/sq) of the prepared fine carbon fiber film was measured using a four-probe resistivity meter (Loresta-GP, MCP-T610, manufactured by Mitsubishi Chemical Corporation).

In addition, in the following experiments, the following substances were prepared as a polymer dispersant, an organic solvent, and a surfactant.

Polymer dispersant:

Sekisui Chemical Co., Ltd. S-LEC B BL-1

Sekisui Chemical Co., Ltd. S-LEC B BL-S

Organic solvents:

Ethanol (EtOH)

Methyl ethyl ketone (MEK)

Toluene

N-methyl-2-pyrrolidone (NMP)

Isopropyl Alcohol (IPA)

Anionic surfactants:

Homogenol L-1820 manufactured by Kao Corporation

Nonionic Surfactants:

SORPOL T-18D

SORPOL7290P

<Volume resistance value of conductive film produced using fine carbon fiber paste>

The fine carbon fiber paste was applied onto electrodes for lithium ion batteries (copper thin film, aluminum thin film) with an applicator, and dried at 120° C. for 10 minutes with a drier. The dried film was subjected to compression processing with a roll press to produce a conductive film for measurement. The volume resistance value in the thickness direction was measured with YOKOGAWA (Programmable DC source7651) and YOKOGAWA (Digital multimeter7555).

<Examples 1 to 13>

As fine carbon fibers, multiwalled carbon nanotubes (NT-7K, average fiber diameter 40 to 80 nm) and (CT-12K, average fiber diameter 100 to 120 nm) manufactured by Hodogaya Chemical Industry Co., Ltd. were prepared.

Mix the polymer dispersant B (g) and surfactant C (g) shown in Table 1 in the organic solvent A (g) shown in Table 1, and after uniform dissolution, mix the amount D (g) shown in Table 1 The above-mentioned fine carbon fibers were dispersed using a bead mill disperser to obtain a fine carbon fiber dispersion.

In addition, as a bead mill disperser, a Dinomill MULTI LAB type (manufactured by SHINMARU ENTERPRISES Corporation) was used.

The viscosity of the obtained dispersion liquid was measured by the method just described, and the evaluation of the dispersibility and the measurement of the surface resistance of the coating film obtained from this dispersion liquid were performed, and the results are shown in Table 1.

1 to 26 show micrographs at magnifications of 2.8 times and 35 times in each example for dispersibility. In addition, for Examples 2, 4, 8, and 10, micrographs (magnification: 35 times) showing the dispersion state of the dispersion liquid after 4 months have passed are shown in FIGS. 37 to 44 .

<Comparative examples 1 to 5>

Do not add polymer dispersant and surfactant, carry out dispersion treatment with the conditions shown in Table 1 (the same conditions as embodiment 1, 3, 5, 7 or 9) and prepare fine carbon fiber dispersion liquid, carry out and embodiment 1～ 13 The same measurement was performed, and the results are shown in Table 1. Micrographs showing the dispersion state of the dispersion liquid are shown in FIGS. 27 to 36 . [Table 1]

From the above experimental results, it can be seen that the fine carbon fiber dispersions (Examples 1 to 13) of the present invention prepared using a specific polymer dispersant are defibrated and dispersed to a small size of 5 μm or less aggregates of fine carbon fibers. .

In addition, it can be understood from the micrographs of FIGS. 37 to 44 that even after 4 months in the fine carbon fiber dispersion liquid of the present invention, the fine carbon fibers do not re-aggregate and are dispersed stably while maintaining a fine size.

Furthermore, it was found that even when the amount of fine carbon fibers added is large, the viscosity is low.

Furthermore, the use of a polymer dispersant does not lower the conductivity of the formed film.

In the fine carbon fiber dispersions prepared without using a polymer dispersant (Comparative Examples 1 to 5), aggregates of fine carbon fibers could not be defibrated to a small size of 5 μm or less. In addition, the viscosity of the dispersion liquid is also higher than that of the present invention.

<Dispersion Stability of Fine Carbon Fiber Dispersion Liquid Added with Resin Component>

After adding 30 g of a styrene-acrylate copolymer resin solution (30% by weight resin solution, manufactured by MARUAI Corporation) as an additive to 7.5 g of the fine carbon fiber dispersions of Examples 4 and 6, to the dispersion of Example 4, add 7.5 g of toluene, and 7.5 g of MEK were added to the dispersion of Example 6, stirred and mixed to prepare a fine carbon fiber dispersion containing a resin solution.

The dispersed state of the fine carbon fibers in the obtained dispersion was observed in the same manner as in Examples 1 to 13, and micrographs at a magnification of 35 times are shown in FIG. 45 (Example 4) and FIG. 46 (Example 6).

From this photograph, it can be understood that in the fine carbon fiber dispersion liquid of the present invention, even when a resin component is added, aggregates exceeding 5 μm in size do not exist, and re-aggregation of fine carbon fibers does not occur.

<Example 14>

As the fine carbon fiber dispersion liquid, the N-methyl-2-pyrrolidone dispersion liquid prepared in Example 13 containing 10 wt% of CT-12K was used.

150 g of lithium cobalt oxide (Cellseed C-5H manufactured by NIPPON CHEMICAL INDUSTRIAL Co., Ltd.) as the positive electrode active material and acetylene black as the conductive auxiliary material were mixed using a three-arm planetary disperser (manufactured by Inoue Seisakusho). (DENKABLACK HS-100 manufactured by DENKI KAGAKU KOGYO KABUSHIKI KAISHA) 3.3g was mixed. 32.5 g of an N-methyl-2-pyrrolidone solution (KF Polymer W#1700 manufactured by KUREHA Corporation) of 12 wt% PVDF was added thereto and kneaded.

Thereafter, 33 g of the fine carbon fiber dispersion of Example 13 was added and mixed, and finally, to adjust the solid content concentration, 9.5 g of N-methyl-2-pyrrolidone solution of 12 wt % PVDF and 3.3 g of N-methyl-2-pyrrolidone were added , stirred and mixed to prepare a fine carbon fiber paste (solid content concentration 70%).

The viscosity of this fine carbon fiber paste is 3.0 Pa·s, and electron micrographs showing the dispersed state of fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 1.97×10 ³ Ωcm.

<Example 15>

As the fine carbon fiber liquid, it was prepared based on Example 14 except that the N-methyl-2-pyrrolidone dispersion liquid containing 10 wt % NT-7K prepared in Example 12 was used.

The viscosity of this fine carbon fiber paste is 8.5 Pa·s, and the observation results of the dispersion state of fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 4.25×10 ² Ωcm.

<Example 16>

As the fine carbon fiber liquid, the N-methyl-2-pyrrolidone dispersion liquid prepared in Example 13 containing 10 wt% of CT-12K was used.

Add 400 g of lithium iron phosphate (SLFP-PD60 manufactured by Tianjin STL) as an active material for the positive electrode, and 4.4 g of acetylene black (DENKA BLACKHS-100 manufactured by DENKIKAGAKU KOGYO KABUSHIKI KAISHA) as a conductive auxiliary material, and use a three-arm planetary disperser (manufactured by Inoue) prepared disperser), and then, 30 g of N-methyl-2-pyrrolidone solution was added and mixed.

To this solution, 44 g of the fine carbon fiber dispersion of Example 13 and 193.3 g of N-methyl-2-pyrrolidone were added, stirred and mixed, and finally, in order to adjust the solid content concentration, N-methyl-2-pyrrolidone of 12 wt% PVDF was added 296.4 g of the solution was stirred and mixed to prepare a fine carbon fiber paste (solid content concentration: 46%).

The viscosity of the fine carbon fiber paste was 1.2 Pa·s, and the observation results of the dispersion state of the fine carbon fibers in the conductive film produced using it are shown in FIGS.

<Example 17>

As the fine carbon fiber liquid, it was prepared based on Example 16 except that the N-methyl-2-pyrrolidone dispersion liquid containing 10 wt % NT-7K prepared in Example 12 was used.

The fine carbon fiber paste has a viscosity of 3.0 Pa·s, and the observation results of the dispersed state of the fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 2.23×10 ² Ωcm.

<Example 18>

As the fine carbon fiber liquid, the N-methyl-2-pyrrolidone dispersion liquid prepared in Example 13 containing 10 wt% of CT-12K was used.

Add 100g of artificial graphite (HKG-P1 manufactured by JFE CHEMICAL Corporation) and 12.7g of N-methyl-2-pyrrolidone solution (KF PolymerW#9200 manufactured by KUREHA Corporation) of 12wt% PVDF as the active material for the negative electrode, and disperse it using a three-armed planetary Machine (Inoue Seisakusho disperser) for kneading. Thereafter, 7.7 g of an N-methyl-2-pyrrolidone solution and 32 g of an N-methyl-2-pyrrolidone solution of 12 wt % PVDF were added, followed by stirring and mixing. To this solution, 22 g of the fine carbon fiber dispersion liquid of Example 13 was added, stirred and mixed to prepare a fine carbon fiber paste (solid content concentration: 61%).

The viscosity of this fine carbon fiber paste is 0.47 Pa·s, and the observation results of the dispersion state of fine carbon fibers in the conductive film produced using it are shown in FIGS.

<Example 19>

As the fine carbon fiber liquid, it was prepared based on Example 18 except that the N-methyl-2-pyrrolidone dispersion liquid containing 10 wt % NT-7K prepared in Example 12 was used.

The fine carbon fiber paste has a viscosity of 0.5 Pa·s, and the observation results of the dispersed state of the fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 3.90×10 ¹ Ωcm.

<Example 20>

As the fine carbon fiber liquid, the N-methyl-2-pyrrolidone dispersion liquid prepared in Example 13 containing 10 wt% of CT-12K was used.

Add 110 g of lithium titanate (manufactured by TOHO TITANIUM Co., Ltd.) as an active material for the negative electrode, and 2.4 g of Ketjen Black (Ketjen Black EC-300J produced by Lion Corporation) as a conductive auxiliary material, and use a three-arm planetary disperser ( Disperser manufactured by Inoue Seisakusho Co., Ltd.) was used for mixing. To this solution, 12 g of the fine carbon fiber dispersion of Example 13 and 38 g of an N-methyl-2-pyrrolidone solution of 12 wt % PVDF (KF polymer W #1100 manufactured by KUREHA Corporation) were added and mixed with stirring.

Thereafter, 9.8 g of an N-methyl-2-pyrrolidone solution and 11.8 g of an N-methyl-2-pyrrolidone solution of 12 wt % PVDF were added and mixed with stirring. Finally, in order to adjust the solid content concentration, 64 g of N-methyl-2-pyrrolidone solution was added, stirred and mixed to prepare a fine carbon fiber paste (solid content concentration: 50%).

The viscosity of this fine carbon fiber paste is 0.85 Pa·s, and the observation results of the dispersion state of fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 3.25×10 ⁴ Ωcm.

<Example 21>

As the fine carbon fiber liquid, it was prepared based on Example 20 except that the N-methyl-2-pyrrolidone dispersion liquid containing 10 wt % NT-7K prepared in Example 12 was used.

The viscosity of this fine carbon fiber paste is 0.845 Pa·s, and the observation results of the dispersion state of fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 4.31×10 ⁴ Ωcm.

＜Comparative example 6＞

As the fine carbon fiber, the multiwalled carbon nanotube CT-12K (average diameter: 110 nm) manufactured by Hodogaya Chemical Industry Co., Ltd. used in Example 13 was used.

Add 150 g of lithium cobalt oxide as the positive electrode active material, 3.3 g of conductive auxiliary material (acetylene black), 3.3 g of multilayer carbon nanotubes (CT-12K) manufactured by Hodogaya Chemical Industry Co., Ltd., and use a three-arm planetary disperser (Inoue Make the manufactured disperser) to mix.

To the obtained solution, 35.5 g of N-methyl-2-pyrrolidone solution of 12 wt % PVDF was added for kneading, and further, 6.5 g of N-methyl-2-pyrrolidone solution of 12 wt % PVDF, N-methyl-2- 18.2 g of 2-pyrrolidone was stirred and mixed.

Finally, in order to adjust the solid content concentration, 14.8 g of N-methyl-2-pyrrolidone solution was added, stirred and mixed, and a fine carbon fiber paste (solid content concentration 70%) was prepared.

The viscosity of this fine carbon fiber paste was 1.41 Pa·s, and the observation results of the dispersed state of fine carbon fibers in the conductive film produced using it are shown in FIGS.

＜Comparative example 7＞

As the fine carbon fibers, the multiwalled carbon nanotubes (CT-12K, average fiber diameter 100 to 120 nm) manufactured by Hodogaya Chemical Industry Co., Ltd. used in Example 13 were used.

Add 400 g of lithium iron phosphate as the positive electrode active material, 4.4 g of conductive auxiliary material (acetylene black), 4.4 g of multilayer carbon nanotubes (CT-12K) manufactured by Hodogaya Chemical Industry Co., Ltd., and use a three-arm planetary disperser (Inoue Make the manufactured disperser) to mix. Thereafter, 30 g of the N-methyl-2-pyrrolidone solution was added and kneaded. 206 g of N-methyl-2-pyrrolidone was added thereto, followed by stirring and mixing. Furthermore, 101.4 g of N-methyl-2-pyrrolidone solutions of 12 wt % PVDF were added and stirred and mixed.

Finally, in order to adjust the solid content concentration, 195.1 g of an N-methyl-2-pyrrolidone solution of 12 wt % PVDF and 33.3 g of N-methyl-2-pyrrolidone were added to prepare a fine carbon fiber paste with a solid content concentration of 45.6%.

The viscosity of this fine carbon fiber paste is 1.22 Pa·s, and the observation results of the dispersion state of fine carbon fibers in the conductive film produced using it are shown in FIGS.

＜Comparative example 8＞

A fine carbon fiber paste was obtained based on Comparative Example 7 except that multiwalled carbon nanotubes (NT-7K, average fiber diameter 40 to 80 nm) manufactured by Hodogaya Chemical Co., Ltd. used in Example 12 were used as fine carbon fibers.

The viscosity of the fine carbon fiber paste was 1.18 Pa·s, and the observation results of the dispersion state of the fine carbon fibers in the conductive film produced using it are shown in FIGS. In addition, the volume resistance value of this conductive film for lithium ion batteries was 3.59×10 ² Ωcm.

Industrial availability

According to the present invention, by using a specific polymer dispersant, it is possible to obtain a fine carbon fiber dispersion having high dispersion, defibrillation and storage stability and low viscosity. In addition, even for a fine carbon fiber dispersion containing additives such as a resin component, the dispersibility of the fine carbon fibers can be maintained sufficiently. Furthermore, the fine carbon fiber film produced using this fine carbon fiber dispersion has good electrical conductivity. Therefore, they are suitable for use in the field of electronic equipment where static electricity is undesirable, in clean rooms, etc., where antistatic films and low-resistance films are necessary, heat-dissipating resin films, electromagnetic shielding films, electrodes of lithium-ion batteries, and the like.

Claims (19)

1. A fine carbon fiber dispersion liquid, which is a fine carbon fiber dispersion liquid dispersed with fine carbon fibers in an organic solvent, characterized in that it contains a polymer dispersant composed of a polymer represented by the following general formula (1), And the size of aggregates of fine carbon fibers contained in the dispersion is 5 μm or less, In formula (1), R ¹ to R ⁴ independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carboxyl group, an acyl group, an amino group, an aryl group, an aryl group, etc. Oxygen or heterocyclyl, ^R5 and ^R6 independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, an aryl group or a heterocyclic group, ^R5 and ^R6 can also be bonded to each other to form a ring, R ⁷ represents a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyalkyl group, an alkoxy group, an acyloxy group, a carbonyl group, a carboxyl group, a primary amino group, a secondary amino group, a tertiary amino group, an aryl group, an aryloxy group or a heterocyclic ring base, All x, y and z are not 0, and on the condition that the value of (4x+2y+2z) representing the number of carbon atoms in the main chain is 400 to 6000 on average, x, y and z are numbers satisfying the following formula: (x+z)/y=60/40 to 90/10. 2. The fine carbon fiber dispersion according to claim 1, wherein the polymer dispersant is contained in an amount of 1 to 200 parts by mass relative to 100 parts by mass of the fine carbon fibers. 3. fine carbon fiber dispersion liquid according to claim 1, wherein, aforementioned polymer dispersant is represented by following general formula (2):

In formula (2), R ⁵ to R ⁷ and x to z are the same as those represented by the aforementioned general formula (1). 4. fine carbon fiber dispersion liquid according to claim 3, wherein, aforementioned polymer dispersant is represented by following general formula (3):

In formula (3), R ⁸ represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group with 1 to 30 carbon atoms, R ⁹ is an alkyl group, alkylcarbonyl group, aryl group, heterocyclic group, pyranosyl group or furanosyl group with 1 to 30 carbon atoms, and x, y and z are the same as those shown in general formula (1). 5. The fine carbon fiber dispersion according to claim 1, further comprising an anionic surfactant or a nonionic surfactant. 6. fine carbon fiber dispersion liquid according to claim 5, it contains the compound shown in following general formula (4) as aforementioned anionic surfactant: In the formula (4), A is a sodium ion, a potassium ion or an ammonium ion, B is an average number of 1-100, and C is a number of 1-3. 7. The fine carbon fiber dispersion liquid according to claim 5, which contains a compound shown in any one of the following general formula (5), general formula (6) or general formula (7) as the aforementioned nonionic surfactant agent,

In the aforementioned general formulas (5) to (7), R ¹⁰ to R ¹⁴ independently represent a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, a 1-phenyl-ethyl group or a benzyl group, and at least one of R ¹⁰ to R ¹⁴ is not A hydrogen atom, D is a number from 1 to 100 on average, E is a number from 1 to 100 on average, F is a number from 1 to 3, R ¹⁵ to R ¹⁸ independently represent a hydrogen atom, an alkyl group with 1 to 30 carbon atoms, a hydroxyl group, a hydroxyalkyl group, and a 1-phenyl-ethyl group, and at least one of R ¹⁵ to R ¹⁸ is not a hydrogen atom, G is a number from 10 to 50 on average. 8. The fine carbon fiber dispersion according to claim 1, wherein the fine carbon fibers have an average outer diameter of 0.5 to 200 nm. 9. The fine carbon fiber dispersion according to claim 1, which has a viscosity of 0.2 to 100 Pa·s (20°C). 10. The fine carbon fiber dispersion liquid according to claim 9, which is used in the formation of lithium ion battery electrodes. 11. The fine carbon fiber dispersion according to claim 10, wherein an electrode active material for negative electrodes or an electrode active material for positive electrodes is added. 12. The fine carbon fiber dispersion according to claim 11, wherein the electrode active material for negative electrode is at least one selected from the group consisting of carbon-based active materials, silicon-based active materials, and lithium titanate. 13. The fine carbon fiber dispersion according to claim 11, wherein the aforementioned positive electrode active material is selected from layered rock salt compounds and derivatives thereof, spinel compounds and derivatives thereof, polyanionic compounds and derivatives thereof At least one of the group consisting of objects. 14. A paste for lithium ion battery electrodes, which has a viscosity of 0.2 to 100 Pa·s (20° C.) by adding an electrode active material for negative electrodes or an electrode active material for positive electrodes to a fine carbon dispersion. 15. The lithium ion battery electrode paste according to claim 14, wherein the electrode active material for the aforementioned negative electrode is at least one selected from the group consisting of natural graphite, artificial graphite, silicon-based active material and lithium titanate. kind. 16. The lithium ion battery electrode paste according to claim 14, wherein the aforementioned positive electrode active material is selected from layered rock salt compounds and derivatives thereof, spinel compounds and derivatives thereof, polyanion compounds At least one of the group consisting of and its derivatives. 17. An electrode conductive film for a lithium ion battery obtained by applying the paste for a lithium ion battery electrode according to claim 14. 18. A conductive film for lithium ion batteries obtained by applying the paste for lithium ion battery electrodes according to claim 14 to a metal thin film. 19. A lithium ion battery obtained using the electrode conductive film for lithium ion batteries according to claim 17.

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