JP2018083722A - Method of manufacturing flaky carbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method making it possible to obtain flaky carbon in a state in which the flaky carbon can be stably dispersed, by using an inexpensive material and a simple process.SOLUTION: A method of manufacturing flaky carbon includes: placing a composition containing a carbonaceous material having a layer structure and a compound having fluorene skeleton between a turntable to be rotated and a board placed approximately parallel to the turntable; and applying shear to the carbonaceous material having the layer structure in the composition while making control so that a shortest distance between the turntable and the board is 200 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing flaky carbon. In particular, flaky carbon, flaky carbon composition for use in conductive materials, heat transfer materials, power storage devices such as transistors and capacitors, sensors, piezoelectric materials, antibacterial materials, filtration materials, resin additives, optical materials, Alternatively, the present invention relates to a method for producing a flaky carbon dispersion.

A graphene sheet is a two-dimensional single-layer sheet in which carbon atoms are arranged in a honeycomb lattice shape, and is also a structural unit such as graphite, fullerene, and carbon nanotube. The flaky carbon in which the graphene sheet is laminated to a thickness of about 10 nm or less (in the present invention, the concept including the graphene sheet) has its unique properties (for example, a Young's modulus of 1.0 TPa in the case of a single-layer graphene sheet) Carrier mobility 200000cm ² V ^-1 s ^-1 , electrical conductivity 30Ω □ ^-1 , thermal conductivity 5000Wm ^-1 K ^-1 etc.), conductive material, heat transfer material, transistor, capacitor Has attracted attention as a new material used for electricity storage devices, sensors, piezoelectric materials, antibacterial materials, filtration materials, resin additives, optical materials and the like.

As a method for producing flaky carbon,
(1) Mechanical exfoliation method using tape, etc. (2) Formation on metal foil by CVD (3) Heating of SiC substrate (4) Delamination by oxidation of graphite and reduction of graphene oxide obtained ing.

  Among these, the methods (1) to (3) have problems in mass productivity and are difficult to isolate because flaky carbon is obtained on a substrate or attached to a tape. In particular, in the case of flaky carbon having a small thickness, it is almost impossible to isolate the flaky carbon by peeling off from these substrates or tapes. Moreover, even if it can be isolated, the flaky carbon obtained by these methods is very easily aggregated, and it is very difficult to isolate it in a dispersed state. It is also very difficult to peel off the agglomerated flaky carbon.

  On the other hand, the method (4) is a process in which graphite oxide produced by oxidizing graphite is delaminated by ultrasonic treatment or the like to obtain graphene oxide, which is then reduced to graphene. When this method is employed, if graphene oxide is reduced in the liquid, aggregation occurs and film formation cannot be performed. In addition, it is difficult to peel off the aggregated graphene one by one. In order to prevent agglomeration after reduction, the coexistence of a surfactant such as sodium dodecylbenzenesulfonate has been studied (Non-patent Document 1). However, since intense oxidation and reduction are performed, it is very difficult to obtain flaky carbon while maintaining the graphene structure, and there is also a problem in safety. Furthermore, even if this method is adopted, flaky carbon is precipitated, and dispersion stabilization in the liquid has not been achieved.

  Thus, although flaky carbon has excellent physical properties, it is very difficult to isolate it in a dispersed state, and a method for this is required.

Adv. Funct. Mater. 2010, 20, 2893-2902

  An object of the present invention is to provide a method that can be obtained in a state in which flaky carbon can be stably dispersed using an inexpensive material and a simple process.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined that a carbonaceous material having a layered structure and a carbonaceous material having a layered structure in a composition containing a compound having a fluorene skeleton are predetermined. It has been found that by applying shear by the method, the flaky carbon can be obtained in a state where it can be stably dispersed despite using an inexpensive material and a simple process. The inventors of the present invention have further studied based on the findings and have completed the present invention. That is, this invention includes the following structures.

Item 1. A method for producing flaky carbon,
Between a rotating rotating disk and a disk installed substantially parallel to the rotating disk,
A composition comprising a carbonaceous material having a layered structure and a compound having a fluorene skeleton;
A manufacturing method comprising a step of applying shear to a carbonaceous material having a layered structure in the composition while adjusting the shortest distance between the rotating disk and the disk to be 200 μm or less.

  Item 2. Item 2. The manufacturing method according to Item 1, wherein the step of applying shear is a step of rotating the rotating disk.

  Item 3. Item 3. The method according to Item 1 or 2, wherein the composition further contains a solvent.

  Item 4. Item 4. The production method according to Item 3, wherein the solvent contains water, and the content of the water is 60% by weight or more in the solvent.

  Item 5. Item 5. The production method according to any one of Items 1 to 4, wherein the compound having a fluorene skeleton is a water-soluble compound having a fluorene skeleton.

  Item 6. Item 6. The production method according to any one of Items 1 to 5, wherein the compound having a fluorene skeleton is an organic ammonium salt, an alkali metal salt, an ammonium salt, or an alkylene oxide adduct of the compound having a fluorene skeleton.

  Item 7. The compound having a fluorene skeleton is represented by the general formula (1):

[Wherein, Z ¹ and Z ² are the same or different and each represents an aromatic hydrocarbon ring. R ^1a and R ^1b are the same or different and each represents a hydrocarbon group, an alkoxy group, a halogen atom, a nitro group, a cyano group, or an optionally substituted amino group. R ^2a and R ^2b are the same or different and each represents an alkylene group. R ^3a and R ^3b are the same or different and are hydrocarbon group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, alkoxycarbonyl group, halogen atom, nitro group, cyano group or substituted. May represent a good amino group. m1 and m2 are the same or different and represent an integer of 0 or more. p1 and p2 are the same or different and represent an integer of 1 or more. h1 and h2 are the same or different and represent an integer of 0 to 4. j1 and j2 are the same or different and represent an integer of 0 to 4. ]
Item 7. The production method according to any one of Items 1 to 6, which is an organic ammonium salt, alkali metal salt, ammonium salt, or alkylene oxide adduct of a fluorene compound represented by the formula:

Item 8. Item 8. The production method according to Item 7, wherein in the general formula (1), Z ¹ and Z ² are the same or different and are a benzene ring or a naphthalene ring.

  Item 9. Item 9. The production method according to Item 7 or 8, wherein m1 and m2 are both 0 in the general formula (1).

  Item 10. Item 10. The production method according to any one of Items 7 to 9, wherein the compound having a fluorene skeleton is an organic ammonium salt and / or an alkali metal salt of the compound represented by the general formula (1).

  Item 11. Item 11. The manufacturing method according to any one of Items 1 to 10, wherein the step of applying shear is performed while adjusting the shortest distance between the rotating disk and the disk to be 50 μm or less.

  Item 12. Item 12. The manufacturing method according to any one of Items 1 to 11, wherein an axis perpendicular to the rotating disc and an axis perpendicular to the disc are parallel.

  Item 13. Item 13. The method according to any one of Items 1 to 12, wherein the content of the carbonaceous material having a layered structure in the composition is 20% by weight or less.

  Item 14. Item 14. The method according to any one of Items 3 to 13, further comprising a step of drying the solvent after the step of applying the shear.

  Item 15. Item 15. A method for producing flaky carbon, comprising a step of removing the compound having a fluorene skeleton by washing the flaky carbon obtained by the production method according to any one of Items 1 to 14 with water or an organic solvent.

  According to the present invention, flaky carbon can be obtained in a state where it can be stably dispersed using an inexpensive material and a simple process.

  Further, according to the present invention, the flaky carbon is a flaky carbon-containing material of any aspect of the flaky carbon alone, the flaky carbon composition, and the flaky carbon dispersion, while suppressing aggregation. Can be obtained. That is, the versatility is high because the form to be used can be appropriately set according to the application. In particular, since the flaky carbon can be easily isolated and the flaky carbon can be uniformly mixed with other materials, application to a nanocomposite containing the flaky carbon is also expected.

2 is a scanning electron microscope (SEM) photograph of flaky carbon obtained in Example 2. FIG. 3 is a scanning electron microscope (SEM) photograph of flaky carbon obtained in Example 4. FIG.

1. Method for producing flaky carbon dispersion In the method for producing flaky carbon of the present invention, a carbonaceous material having a layered structure between a rotating rotating disk and a disk installed substantially parallel to the rotating disk, and A composition containing a compound having a fluorene skeleton was installed, and the carbonaceous material having a layered structure in the composition was sheared while adjusting the shortest distance between the rotating disk and the disk to be 200 μm or less. Add

  According to this shearing method, the direction in which the force is applied is parallel to the plane direction of the carbonaceous material having a layered structure, and the processing is performed in a narrow space, so that manufacturing by conventional high-speed stirring, ultrasonic processing, high-pressure processing, etc. Compared with the method, there is less breakage, and it is possible to obtain flaky carbon of a larger size (for example, flaky carbon with a size of 1 μm or more), and it is easy to peel and can be processed in a short time (small number of passes) In addition, it is difficult to leave a thick lump that has failed to peel off.

Carbonaceous material having a layered structure The carbonaceous material having a layered structure is not particularly limited, and examples thereof include natural graphite, artificial graphite, expanded graphite, earthy graphite, and graphite oxide. As the graphite oxide, for example, graphite oxidized with one or more oxidizing agents such as sulfuric acid, nitric acid, potassium permanganate, hydrogen peroxide and the like can be used. For example, when obtaining graphite oxide by the Hammers method, after immersing graphite in concentrated sulfuric acid, adding potassium permanganate to oxidize graphite, the reaction is quenched with dilute sulfuric acid and / or hydrogen peroxide, Thereafter, by washing with distilled water or the like, oxygen atoms are bonded to carbon atoms, and oxygen atoms are introduced between layers to obtain graphite oxide.

  In particular, when obtaining flaky carbon having a high purity that does not contain hetero atoms such as oxygen, graphite is preferably used as a raw material, and natural graphite and expanded graphite are more preferable. In addition, when using expanded graphite, it is preferable to employ | adopt expanded graphite with little oxidation of a graphene structure. Moreover, when using expanded graphite, it can also be used after adding heat processing at about 300-1000 degreeC for about 10 second-5 hours. Thereby, it is also possible to use the expanded graphite expanded moderately.

  In addition, graphite oxide can also be used when importance is attached to manufacturing. By using graphite oxide, it is easy to insert solvent molecules between layers, it is easy to peel only in the layer direction, and the thinning efficiency and dispersibility are improved, so the processing time can be shortened. is there. However, when graphite oxide is used, reduction treatment is necessary later, and from the viewpoint of maintaining the graphene structure, conductivity and strength, other materials (natural graphite, artificial graphite, expanded graphite, earthy graphite) Is preferred.

  On the other hand, in order to further improve dispersibility, earth graphite can be employed. However, from the viewpoint of crystallinity, purity, and structure maintenance, other materials (natural graphite, artificial graphite, expanded graphite, graphite oxide) are preferable.

  Artificial graphite can also be used when importance is attached to the crystallinity, strength, structure maintenance, etc. of the flaky carbon obtained.

  In the present invention, the content of the carbonaceous material having a layered structure in the composition is not particularly limited, is preferably 20% by weight or less, more preferably 0.0001 to 15% by weight, and further preferably 0.001 to 10% by weight. . In addition, the content of the carbonaceous material having a layered structure tends to make flaky carbon more efficient because thinning (delamination) is more likely to occur, and there is a tendency that the number of treatments can be reduced, The flaky carbon can be obtained more efficiently by shearing while maintaining the viscosity appropriately. On the other hand, the higher the content of the carbonaceous material having a layered structure, the better the productivity. For this reason, it is preferable to appropriately set the content of the carbonaceous material having a layered structure from the viewpoint of the balance of flaking efficiency, viscosity, productivity, and the like. In the production method of the present invention, when a carbonaceous material dispersion is used, the content of the carbonaceous material having a layered structure in the dispersion is preferably within the above range.

Compounds having a fluorene skeleton Conventionally, when producing flaky carbon by a wet method, the aqueous dispersion containing the flaky carbon oxide and an aqueous solvent has been subjected to a reduction treatment, but this method maintains the graphene structure. In addition, it is difficult to obtain a flaky carbon water dispersion because the obtained flaky carbon agglomerates violently. There was also a problem in terms of safety. Although a flaky carbon water dispersion can be obtained when performing high-pressure treatment, the flaky carbon obtained tends to be broken and tends to take a long time to manufacture, and a lump that has failed to peel off remains. There was also. On the other hand, in the present invention, by using a compound having a fluorene skeleton, flaky carbon is obtained in a uniformly dispersed state (flaky carbon dispersion etc.) without agglomerating flaky carbon maintaining the graphene structure. The flaky carbon obtained can be hardly destroyed, and the flaky carbon can be obtained in a short time, and the lump that has failed to be peeled off hardly remains. At this time, the compound having a fluorene skeleton can also function as a dispersant for uniformly dispersing the flaky carbon.

  As such a compound having a fluorene skeleton, a water-soluble compound having a fluorene skeleton is preferable because water is used as a main solvent as a solvent for the flaky carbon dispersion as described later. For example, the general formula (1):

[Wherein, Z ¹ and Z ² are the same or different and each represents an aromatic hydrocarbon ring. R ^1a and R ^1b are the same or different and each represents a hydrocarbon group, an alkoxy group, a halogen atom, a nitro group, a cyano group, or an optionally substituted amino group. R ^2a and R ^2b are the same or different and each represents an alkylene group. R ^3a and R ^3b are the same or different and are hydrocarbon group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, alkoxycarbonyl group, halogen atom, nitro group, cyano group or substituted. May represent a good amino group. m1 and m2 are the same or different and represent an integer of 0 or more. p1 and p2 are the same or different and represent an integer of 1 or more. h1 and h2 are the same or different and represent an integer of 0 to 4. j1 and j2 are the same or different and represent an integer of 0 to 4. ]
An organic ammonium salt, an alkali metal salt, an ammonium salt, or an alkylene oxide adduct of a fluorene compound represented by the formula:

In the general formula (1), Z ¹ and Z ² are preferably aromatic hydrocarbon rings having 6 to 14 carbon atoms, more preferably monocyclic or condensed aromatic hydrocarbon rings having 6 to 14 carbon atoms. Further, a monocyclic or bicyclic aromatic hydrocarbon ring having 6 to 10 carbon atoms is more preferable. Specific examples include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, an indene ring, and the like, and a benzene ring and a naphthalene ring are more preferable. Among these, when importance is attached to the water solubility of the compound having a fluorene skeleton, a benzene ring is preferable, and when importance is attached to the carbonaceous material having a layered structure, a naphthalene ring is preferable. Z ¹ and Z ² may be the same or different.

In the general formula (1), R ^1a and R ^1b are an optionally substituted hydrocarbon group (an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl). A group, an optionally substituted aralkyl group, etc.), an optionally substituted alkoxy group, a halogen atom, a nitro group, a cyano group, an optionally substituted amino group, and the like.

In the general formula (1), the alkyl group represented by R ^1a and R ^1b is preferably a linear or branched alkyl group having 1 to 8 (particularly 1 to 6) carbon atoms, specifically, A methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like are preferable. This alkyl group can also have a substituent. Examples of the substituent include a hydroxyl group, a cycloalkyl group described later, an aryl group described later, an aralkyl group described later, an alkoxy group described later, a halogen atom, a nitro group, a cyano group described later, an amino group described later, a cycloalkoxy group described later, Examples include an aryloxy group described below, an aralkyloxy group described below, an acyl group described below, and an alkoxycarbonyl group described below. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the cycloalkyl group represented by R ^1a and R ^1b is preferably a cycloalkyl group having 5 to 10 carbon atoms (preferably 5 to 8, particularly 5 to 6 carbon atoms). A cyclopentyl group, a cyclohexyl group and the like are preferable. This cycloalkyl group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, a later-described aryl group, a later-described aralkyl group, a later-described alkoxy group, a later-described halogen atom, a nitro group, a cyano group, a later-described amino group, and a later-described cyclo group. Examples include an alkoxy group, an aryloxy group described later, an aralkyloxy group described later, an acyl group described later, and an alkoxycarbonyl group described later. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the aryl group represented by R ^1a and R ^1b is preferably an aryl group having 6 to 10 carbon atoms, specifically, a phenyl group or an alkylphenyl group (a group having an alkyl group as described above). A tolyl group such as o-tolyl group, m-tolyl group, p-tolyl group and the like; a xylyl group and the like), a naphthyl group and the like are preferable. This aryl group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, an aralkyl group described later, an alkoxy group described later, a halogen atom, a nitro group, a cyano group described later, an amino group described later, and a cycloalkoxy described later. Group, an aryloxy group described later, an aralkyloxy group described later, an acyl group described later, an alkoxycarbonyl group described later, and the like. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the aralkyl group represented by R ^1a and R ^1b is preferably an aralkyl group having 7 to 14 carbon atoms having the aryl group and the alkyl group, specifically, a benzyl group or a phenethyl group. Etc. are preferred. This aralkyl group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, a later-described alkoxy group, a later-described halogen atom, a nitro group, a cyano group, a later-described amino group, and a later-described cycloalkoxy group. And an aryloxy group described later, an aralkyloxy group described later, an acyl group described later, an alkoxycarbonyl group described later, and the like. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the alkoxy group represented by R ^1a and R ^1b is preferably an alkoxy group having 1 to 8 carbon atoms (particularly 1 to 6), specifically, a methoxy group, an ethoxy group, or a propoxy group. Isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group and the like are preferable. This alkoxy group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, a later-described amino group, a later-described cycloalkoxy group, Examples include an aryloxy group described below, an aralkyloxy group described below, an acyl group described below, and an alkoxycarbonyl group described below. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), examples of the halogen atom represented by R ^1a and R ^1b include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In the general formula (1), the ^optionally substituted amino group represented by R ^1a and R ^1b includes the above-described groups (hydroxyl group, alkyl group, cycloalkyl group, aryl group, aralkyl, in addition to the unsubstituted amino group) Group, alkoxy group, halogen atom, nitro group, cyano group, etc.) or a group to be described later (cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, alkoxycarbonyl group, etc.) are preferred. Specifically, a substituted amino group is preferable, and a dialkylamino group such as a dimethylamino group is more preferable.

Among these, R ^1a and R ^1b are appropriately set from the viewpoints of water solubility of the compound having a fluorene skeleton, thinning efficiency of the carbonaceous material having a layered structure, dispersibility of the obtained flaky carbon, and the like. It is preferable that the hydrocarbon group, further an alkyl group, particularly an alkyl group having 1 to 6 carbon atoms (especially an unsubstituted alkyl group), and further an alkyl group having 1 to 4 carbon atoms such as a methyl group (particularly non-oxygen). Substituted alkyl groups) and the like can be preferably used.

In addition, when j1 is plural (an integer of 2 to 4), the plural groups R ^1a may be the same or different from each other. Similarly, when j2 is plural (an integer of 2 to 4), the plural groups R ^1b may be the same or different from each other.

Further, the groups R ^1a and R ^1b substituted on different benzene rings may be the same or different from each other. Further, the bonding position (substitution position) of the groups R ^1a and R ^1b is not particularly limited, and examples thereof include at least one of the 2-position, the 7-position and the like of the fluorene ring.

In the general formula (1), j1 and j2 which are the number of substitutions of the groups R ^1a and R ^1b may be the same or different, but are usually an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, more preferably 0.

In the general formula (1), R ^2a and R ^2b are preferably an alkylene group, particularly an alkylene group having 2 to 4 carbon atoms, and specific examples include an ethylene group, a propylene group, a trimethylene group, and a tetramethylene group. . Further, the types of the alkylene groups R ^2a and R ^2b may differ depending on the number of coefficients m1 and m2. Among these, an alkylene group having 2 to 3 carbon atoms is preferable, an ethylene group and a trimethylene group are more preferable, and an ethylene group is further preferable.

When m1 is plural (an integer of 2 or more), the plural groups R ^2a may be the same or different from each other. Similarly, when m2 is plural (an integer of 2 or more), the plural groups R ^2b may be the same or different from each other.

Further, the group R ^2a and the group R ^2b may be the same or different from each other.

In the general formula (1), m1 and m2 which are the repeating numbers of OR ^2a and OR ^2b may be the same or different and are integers of 0 or more, but are usually an integer of 0 to 10, preferably 0 to 7 An integer of 0, more preferably an integer of 0 to 5, more preferably an integer of 0 to 3, more preferably 0 or 1, and further 0.

In the general formula (1), p1 and p2 which are the repeating numbers of the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group may be the same or different. Well, it is an integer of 1 or more, but it is usually an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 1 or 2, and still more preferably 1.

In the general formula (1), the substitution positions of the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group are not particularly limited, and the rings Z ¹ and Z Substitution at the appropriate substitution position of ² is sufficient. For _{^{example, -O- (R 2a O) m1}} -H group and -O- (R ^2b O) _m2 -H group, when Ring Z ¹ and Z ² is a benzene ring, a 2-6 position of the benzene ring It may be substituted, and is preferably substituted at the 4-position. The —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group may be a condensed polycyclic ring when the rings Z ¹ and Z ² are condensed polycyclic hydrocarbon rings. In the formula hydrocarbon ring, it is often substituted at least with a hydrocarbon ring different from the hydrocarbon ring bonded to the 9-position of fluorene (for example, the 5-position, 6-position, etc. of the naphthalene ring).

In the general formula (1), R ^3a and R ^3b may be substituted with an ^optionally substituted hydrocarbon group (an optionally substituted alkyl group, an optionally substituted cycloalkyl group, etc.). Aryl group, optionally substituted aralkyl group, etc.), optionally substituted alkoxy group, optionally substituted cycloalkoxy group, optionally substituted aryloxy group, optionally substituted aralkyl. An oxy group, an optionally substituted acyl group, an optionally substituted alkoxycarbonyl group, a halogen atom, a nitro group, a cyano group, an optionally substituted amino group, and the like are preferable.

In the general formula (1), an ^optionally substituted hydrocarbon group represented by R ^3a and R ^3b (an optionally substituted alkyl group, an optionally substituted cycloalkyl group, etc.) As the aryl group, the aralkyl group which may be substituted, the alkoxy group which may be substituted, the halogen atom, and the amino group which may be substituted, the groups exemplified above may be employed.

In the general formula (1), the cycloalkoxy group represented by R ^3a and R ^3b is preferably a C 5-10 cycloalkoxy group, specifically a cyclohexyloxy group or the like. This cycloalkoxy group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, the amino group, the cycloalkoxy group, which will be described later, Examples include an aryloxy group, an aralkyloxy group described later, an acyl group described later, an alkoxycarbonyl group described later, and the like. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the aryloxy group represented by R ^3a and R ^3b is preferably an aryloxy group having 6 to 10 carbon atoms having the aryl group, specifically a phenoxy group or the like. This aryloxy group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, the amino group, the cycloalkoxy group, and the aryl described later. Examples thereof include an oxy group, an aralkyloxy group described later, an acyl group described later, and an alkoxycarbonyl group described later. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the aralkyloxy group represented by R ^3a and R ^3b is preferably a C 7-14 aralkyloxy group having the aryl group and the alkyloxy group, specifically, benzyloxy Groups and the like are preferred. This aralkyloxy group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, the amino group, the cycloalkoxy group, and the aryl described later. Examples thereof include an oxy group, the aralkyloxy group, an acyl group described later, and an alkoxycarbonyl group described later. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the acyl group represented by R ^3a and R ^3b is preferably an acyl group having 1 to 6 carbon atoms, and specifically an acetyl group or the like is preferable. This acyl group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, the amino group, the cycloalkoxy group, and the aryl described later. Examples thereof include an oxy group, the aralkyloxy group, the acyl group, and an alkoxycarbonyl group described later. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

In the general formula (1), the alkoxycarbonyl group represented by R ^3a and R ^3b is preferably an alkoxycarbonyl group having 1 to 4 carbon atoms, specifically a methoxycarbonyl group or the like. This alkoxycarbonyl group can also have a substituent. Examples of the substituent include a hydroxyl group, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, the alkoxy group, a halogen atom, a nitro group, a cyano group, the amino group, the cycloalkoxy group, and the aryl described later. Examples thereof include an oxy group, the aralkyloxy group, the acyl group, and the alkoxycarbonyl group. There is no restriction | limiting in particular in the number of a substituent in the case of having a substituent, 1-6 pieces are preferable and 1-3 are more preferable.

Among these, R ^3a and R ^3b are appropriately set from the viewpoints of water solubility of the compound having a fluorene skeleton, thinning efficiency of the carbonaceous material having a layered structure, dispersibility of the obtained flaky carbon, and the like. Are preferred, but a hydrocarbon group, further an alkyl group, an aryl group, etc., particularly an alkyl group having 1 to 6 carbon atoms (particularly an unsubstituted alkyl group), an aryl group having 6 to 10 carbon atoms (particularly an unsubstituted aryl group) Further, an alkyl group having 1 to 4 carbon atoms (particularly an unsubstituted alkyl group) such as a methyl group, an aryl group having 6 to 8 carbon atoms such as a phenyl group (particularly an unsubstituted aryl group), etc. are preferably used. obtain.

When h1 is plural (an integer of 2 or more), the plural groups R ^3a may be the same or different from each other. Similarly, when h2 is plural (an integer of 2 or more), the plural groups R ^3b may be the same or different from each other.

Further, the group R ^3a and the group R ^3b may be the same or different from each other.

In the general formula (1), h1 and h2 which are the number of substitutions of the groups R ^3a and R ^3b may be the same or different, but are usually an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, more preferably 0.

In the general formula (1), the substitution positions of the groups R ^3a and R ^3b are not particularly limited as long as they are substituted at appropriate substitution positions on the rings Z ¹ and Z ² . For example, when the rings Z ¹ and Z ² are benzene rings, the groups R ^3a and R ^3b may be substituted at the 2-6 positions of the benzene ring, and are substituted at the 3-position or 5-position. preferable. The groups R ^3a and R ^3b are different from the hydrocarbon ring bonded to the 9-position of fluorene in the condensed polycyclic hydrocarbon ring when the rings Z ¹ and Z ² are condensed polycyclic hydrocarbon rings. In many cases (for example, the 5-position, 7-position, 8-position, etc. of the naphthalene ring).

  The fluorene compound represented by the general formula (1) is hardly soluble in water as it is. In the present invention, since flaky graphene is easily obtained as a dispersion containing water as a main solvent, in the present invention, as a compound having a fluorene skeleton, an organic ammonium salt or an alkali metal of a compound represented by the general formula (1) Salts, ammonium salts, hydrochlorides or alkylene oxide adducts are used.

  As said organic ammonium salt, a quaternary ammonium salt is used suitably, For example, tetraalkylammonium salts, such as a tetramethylammonium salt and a tetraethylammonium salt, are preferable.

  Examples of the alkali metal salt include sodium salt, potassium salt, lithium salt and the like.

  As said alkylene oxide adduct, an ethylene oxide adduct etc. are mentioned, for example.

  Among these, as the compound having a fluorene skeleton used in the present invention, water solubility of the compound having a fluorene skeleton, thinning efficiency of the carbonaceous material having a layered structure, dispersibility of the obtained flaky carbon, etc. From the viewpoint, organic ammonium salts, alkali metal salts, ammonium salts, and the like are preferable, organic ammonium salts, alkali metal salts, and the like are more preferable, and tetraalkyl ammonium salts, sodium salts, potassium salts, and the like are more preferable.

In the compound represented by the general formula (1), only one of the —O— (R ^2a O) _m1 —H group and the —O— (R ^2b O) _m2 —H group forms the salt. Or all of them may form a salt. Among these, it is preferable that all of them form a salt from the viewpoints of water solubility of the compound having a fluorene skeleton, thinning efficiency of the carbonaceous material having a layered structure, dispersibility of the obtained flaky carbon, and the like.

  In other words, the compound having a suitable fluorene skeleton includes the general formula (2):

[Wherein, Z ¹ , Z ² , R ^1a , R ^1b , R ^2a , R ^2b , R ^3a , R ^3b , m1, m2, p1, p2, h1, h2, j1 and j2 are the same as above. X ¹ and X ² are the same or different and each represents an organic ammonium cation, an alkali metal cation, or an ammonium cation. ]
Can be used. In the general formula (2), an organic ammonium cation, an alkali metal cation, and an ammonium cation are cations that can form an organic ammonium salt, an alkali metal salt, and an ammonium salt, respectively.

  Typical compounds having a fluorene skeleton include compounds in which m1 and m2 are 0, that is, 9,9-bis (hydroxyaryl) fluorene organic ammonium salt as a salt of 9,9-bis (hydroxyaryl) fluorenes 9,9-bis (hydroxyaryl) fluorene alkali metal salts, 9,9-bis (hydroxyaryl) fluorene ammonium salts, 9,9-bis (hydroxyaryl) fluorene alkylene oxide adducts, and the like.

The 9,9-bis (hydroxyaryl) fluorenes constituting these compounds include 9,9-- wherein Z ¹ and Z ² are benzene rings and p1 and p2 are 1 in the general formula (1). Bisphenolfluorenes; 9,9-bisnaphtholfluorenes in which Z ¹ and Z ² are naphthalene rings and p1 and p2 are 1, Z ¹ and Z ² are benzene rings, and p1 and p2 are 2 or more 9,9-bis (polyhydroxyphenyl) fluorenes and the like are included.

Specifically, 9,9-bisphenolfluorenes are preferably compounds in which R ^3a and R ^3b are hydrocarbon groups and h1 and h2 are 0 or 1. Examples of the 9,9-bisphenol fluorenes include 9,9-bisphenol fluorenes such as 9,9-bis (4-hydroxyphenyl) fluorene; 9,9-bis (4-hydroxy-2-methylphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (3-hydroxy-6-methylphenyl) fluorene 9,9-bis (alkylhydroxyphenyl) fluorene such as 9,9-bis (2-hydroxy-4-methylphenyl) fluorene, 9,9-bis (4-hydroxy-3-tert-butylphenyl) fluorene ( For example, 9,9-bis (C _1-6 alkylhydroxyphenyl) fluorene, etc.); 9,9-bis (4-hydroxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-hydroxy-2 , 6-Dimethylphenyl) fluorene, 9,9-bis (4-hydroxy-3,5-di-tert-butylphenyl) fluorene Such emissions of 9,9-bis (dialkyl hydroxyphenyl) fluorene (e.g., 9,9-bis (di-C _1-6 alkyl-hydroxyphenyl) fluorene, etc.); 9,9-bis (4-hydroxy-3-phenyl ) 9,9-bis (cycloalkylhydroxyphenyl) fluorene such as fluorene (eg, 9,9-bis (C _5-10 cycloalkylhydroxyphenyl) fluorene); 9,9-bis (4-hydroxy-3- And 9,9-bis (arylhydroxyphenyl) fluorene (eg, 9,9-bis (C _6-10 arylhydroxyphenyl) fluorene) such as phenylphenyl) fluorene.

  Further, the 9,9-bisnaphtholfluorenes include 9,9-bisnaphtholfluorenes (for example, 9,9-bisnaphtholfluorenes in which the phenyl group of the exemplified 9,9-bisphenolfluorenes is a naphthyl group, for example, 9,9-bis [6- (2-hydroxynaphthyl)] fluorene, 9,9-bis [1- (5-hydroxynaphthyl)] fluorene and other 9,9-bisnaphtholfluorene) and the like.

Further, the 9,9-bis (polyhydroxyphenyl) fluorenes include fluorenes corresponding to the 9,9-bis (hydroxyphenyl) fluorenes (9,9-bis (monohydroxyphenyl) fluorenes), For example, 9,9-bis (dihydroxyphenyl) fluorene (9,9-bis (3,4-dihydroxyphenyl) fluorene (biscatechol fluorene) etc.); 9,9-bis (3,4-dihydroxy-5-methyl) 9,9-bis (alkyl-dihydroxyphenyl) fluorene (eg, 9,9-bis (C _1-4 alkyl) such as phenyl) fluorene, 9,9-bis (3,4-dihydroxy-6-methylphenyl) fluorene 9,9-bis (di- or trihydroxyphenyl) fluorenes such as -dihydroxyphenyl) fluorene and the like.

The 9,9-bis (hydroxyaryl) fluorenes include, for example, the fluorenes (that is, 9,9-bisphenolfluorenes, 9,9-bisnaphtholfluorenes, 9,9-bis (dihydroxyphenyl). ) Fluorenes, etc.), a compound in which m1 and m2 are 1 or more, for example, 9,9-bis [4- (9,9-bis (4-hydroxyethoxyphenyl) fluorene (bisphenoxyethanol fluorene; BPEF), etc. 9,9-bis (alkylhydroxy C _2-3 ) such as hydroxy C _2-3 alkoxy) phenyl] fluorene, 9,9-bis (4-hydroxyethoxy-3-methylphenyl) fluorene (biscresol ethanolfluorene; BCEF) Alkoxyphenyl) fluorene and the like are also included.

  That is, the compound having a fluorene skeleton used in the present invention includes any of the above-described organic ammonium salts, alkali metal salts, ammonium salts, and alkylene oxide adducts of fluorenes. Among these, 9,9-bis (4-hydroxyphenyl) fluorene, from the viewpoint of water solubility of the compound having a fluorene skeleton, thinning efficiency of the carbonaceous material having a layered structure, dispersibility of the obtained flaky carbon, etc. 2 Organic ammonium salt, 9,9-bis (4-hydroxyphenyl) fluorene dialkali metal salt, 9,9-bis (4-hydroxyphenyl) fluorene diammonium salt, 9,9-bis (4-hydroxyphenyl) ) Fluorene-2 alkylene oxide adduct, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene-2 organic ammonium salt, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene-2 alkali Metal salt, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene · 2 ammonium salt, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene · 2 alkylene oxide adduct, 9,9 -Bis (4-hydroxynaphthyl ) Fluorene-2 organic ammonium salt, 9,9-bis (4-hydroxynaphthyl) fluorene-2 alkali metal salt, 9,9-bis (4-hydroxynaphthyl) fluorene-2 ammonium salt, 9,9-bis (4 -Hydroxynaphthyl) fluorene / 2 alkylene oxide adducts, etc. are preferred, 9,9-bis (4-hydroxyphenyl) fluorene / 2 organic ammonium salt, 9,9-bis (4-hydroxyphenyl) fluorene / 2 alkali metal salt 9,9-bis (4-hydroxy-3-methylphenyl) fluorene-2 organic ammonium salt, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene-2 alkali metal salt, 9,9-bis (4-Hydroxynaphthyl) fluorene · 2 organic ammonium salt, 9,9-bis (4-hydroxynaphthyl) fluorene · 2 alkali metal salt and the like are more preferable.

  In the present invention, the content of the compound having a fluorene skeleton in the composition is not particularly limited, but is preferably 0.0001 to 50% by weight, more preferably 0.001 to 30% by weight, and still more preferably 0.01 to 10% by weight. On the other hand, in the present invention, the content of the compound having a fluorene skeleton to be charged before the treatment is preferably 10 to 100,000 parts by weight, more preferably 20 to 50000 parts by weight with respect to 100 parts by weight of the carbonaceous material having a layered structure. preferable. In addition, as for the content of the compound having a fluorene skeleton, the content of the carbonaceous material having a layered structure is relatively larger as the content is thinner, so that the conductivity is easily improved and the treatment is inexpensive. On the other hand, the thicker the content of the compound having a fluorene skeleton, the easier the flaking (delamination) occurs, and therefore the flaky carbon tends to be obtained more efficiently. For this reason, it is preferable to appropriately set the content of the compound having a fluorene skeleton from the viewpoint of the balance of conductivity, cost, thinning efficiency, and the like. In the production method of the present invention, when a carbonaceous material dispersion is used, the content of the compound having a fluorene skeleton in the dispersion is preferably within the above range.

Solvent In the present invention, as described above, a specific shearing treatment is performed on a composition containing a carbonaceous material having a layered structure and a compound having a fluorene skeleton, but the flaking efficiency of the carbonaceous material having a layered structure is reduced. From the viewpoint of versatility of the obtained flaky carbon, it is preferable to use a carbonaceous material dispersion containing a carbonaceous material having a layered structure and a compound having a fluorene skeleton.

  The carbonaceous material dispersion may be formed as a dispersion or may be formed as a coating on the substrate.

  At this time, as a solvent used for preparing a dispersion (dispersion or coating film), it is preferable to use water as a main solvent from the viewpoint of the exfoliation efficiency of a carbonaceous material having a layered structure.

  The content of water in the solvent to be used is not particularly limited, and is 60% by weight or more (60 to 100% by weight) from the viewpoint of exfoliation efficiency of a carbonaceous material having a layered structure, solubility of a compound having a fluorene skeleton, and the like. ) Is preferable, and 70 to 100% by weight is more preferable.

  In the present invention, as the solvent, only water may be used, and the organic solvent is not necessarily used, but in order to further improve the solubility of the organic compound having a fluorene skeleton in water, Alcohols such as methanol, ethanol, 2-propanol, tert-butyl alcohol; glycols such as ethylene glycol; glycerin; organic solvents such as 2-methoxyethanol may be used.

  The content of the organic solvent in the solvent to be used is preferably 40% by weight or less (0 to 40% by weight) from the viewpoint of the exfoliation efficiency of the carbonaceous material having a layered structure, the solubility of the compound having a fluorene skeleton, and the like. 0 to 30% by weight is more preferable.

  In the present invention, when a specific shearing treatment is performed using a carbonaceous material dispersion using a solvent, the total amount of the solvent in the carbonaceous material dispersion is not particularly limited, and the flakes of the carbonaceous material having a layered structure From the viewpoint of the conversion efficiency, the solubility of the compound having a fluorene skeleton, etc., 40 to 99.9998% by weight is preferable, 63 to 99.998% by weight is more preferable, and 85 to 99.98% by weight is more preferable.

  In the present invention, when a specific shearing treatment is performed using a carbonaceous material dispersion using a solvent, the carbonaceous material dispersion is obtained by adding a carbonaceous material having a layered structure to a compound dispersion having a fluorene skeleton. Alternatively, a compound having a fluorene skeleton may be added to the carbonaceous material dispersion having a layered structure. In addition, a carbonaceous material having a layered structure and a compound having a fluorene skeleton may be simultaneously added to the solvent.

Other Components In the present invention, the composition containing a carbonaceous material having a layered structure and a compound having a fluorene skeleton (for example, a carbonaceous material dispersion) may contain other components. Thereby, these other components can be contained also in the flaky carbon dispersion and flaky carbon composition finally obtained. Examples of such other components include carbon fibers (particularly carbon nanofibers having a fiber diameter of 500 nm or less), activated carbon, carbon black (acetylene black, oil furnace black, etc .; ketjen black having particularly high conductivity and a large specific surface area). , Glassy carbon, carbon microcoil, fullerene, biomass-based carbon materials (bagasse, sorghum, wood waste, sawdust, bamboo, bark, rice straw, rice husk, coffee grounds, tea shells, okarasu, rice straw, pulp waste, etc. Or carbon fibers produced from lignin) may be used as long as the effects of the present invention are not impaired.

Shearing treatment In the present invention, as described above, a composition comprising a carbonaceous material having a layered structure and a compound having a fluorene skeleton between a rotating rotating disk and a disk installed substantially parallel to the rotating disk ( The carbon material dispersion etc. is installed, and shear is applied to the carbonaceous material having a layered structure in the composition while adjusting the shortest distance between the rotating disk and the disk to be 200 μm or less. .

  Since the carbonaceous material having a layered structure is atomized by applying the shearing process, the graphene structure may not be maintained depending on conditions, but the carbonaceous material having the layered structure is efficiently thinned. And processing time can be reduced. The rotating disk and the disk at the time of performing such a shearing process are installed substantially parallel to each other, but may not be strictly parallel. Specifically, the angle formed by the axis perpendicular to the rotating disk and the axis perpendicular to the disk is preferably 10 ° or less, and more preferably 5 ° or less. It is most preferable that the axis perpendicular to the rotating disk and the axis perpendicular to the disk are strictly parallel. The shortest distance between the rotating disk and the disk when performing such a shearing treatment is not particularly limited as long as the thinning of the carbonaceous material having a layered structure can be sufficiently performed, 200 μm or less, Preferably it is 1-50 micrometers, More preferably, it is 2-30 micrometers. In addition, although the said turntable and the said board are installed substantially parallel, the distance of the said turntable and the said board may change with places. In this case, the shortest distance between the rotating disk and the disk means the shortest distance among the distances between the rotating disk and the disk. In addition, it is not always necessary to vacate the rotating disk and the disk in advance, a material to be processed may be sandwiched between the rotating disk and the disk, and the rotating disk and the disk are in contact with each other, A space between the rotating disk and the disk may be widened by sandwiching a carbonaceous material having a layered structure. Such a shearing process may be performed by using a stone mortar, a vibration mixer, a spin coater, a grinder, or the like as long as it has a mechanism for rotating a disk-shaped object.

  The size of the rotating disk and the disk that can be used at this time is not particularly limited, is preferably 5 to 500 mm, and more preferably 10 to 200 mm. Further, the number of rotations of the rotating disk at the time of performing the shearing treatment is not particularly limited, and is preferably in a range in which the carbonaceous material having a layered structure can be sufficiently thinned, for example, 1000 to 10,000 ppm is preferable. 2000 to 5000 ppm is more preferable.

  By carrying out such a shearing treatment, the carbonaceous material having a lamellar structure is brought into contact with the carbonaceous material having a lamellar structure by contacting the carbonaceous material having a lamellar structure with the carbonaceous material having a lamellar structure. Shear can be applied in a direction parallel to the graphene layer of the carbonaceous material having a structure.

  By reducing the shortest distance between the rotating disk and the rotating disk in the shearing process and increasing the rotating speed of the rotating disk, the conditions can be made stronger, and the flakes of the carbonaceous material having a layered structure Can be performed more efficiently, and the processing time can be further reduced. This shearing operation can be performed one or more times, preferably three or more times.

  The temperature at which the shearing treatment is performed is not particularly limited, and may be a temperature at which thinning of the carbonaceous material having a layered structure can be sufficiently performed, and is set to 0 ° C. or more, further 0 to 100 ° C., particularly 20 to 95 ° C. obtain. In addition, the temperature at which the shearing treatment is performed is good under conditions where the solubility of the compound having a fluorene skeleton is high, and the higher the temperature, the higher the solubility, the higher the temperature is preferable, and when using a compound having a fluorene skeleton having a cloud point It is preferable to keep the temperature below the cloud point.

  Before carrying out the above-mentioned shearing treatment, in order to bring the carbonaceous material having a layered structure into contact with the compound having a fluorene skeleton, it is necessary to stir in advance before preparing the composition using an agitator, an ultrasonic dispersion device or the like. Further, a compound having a fluorene skeleton may be familiarized with the surface of the carbonaceous material having a layered structure.

  In the present invention, when graphite oxide is used as the carbonaceous material having a layered structure, it is present as an oxide of flaky carbon in the dispersion subjected to the shearing treatment. For this reason, when graphite oxide is used as the carbonaceous material having a layered structure, it is preferable to perform a reduction treatment as a post-treatment. As the reduction treatment, various methods such as chemical reduction and electrochemical reduction can be adopted, but chemical reduction is preferable. Of these, chemical reduction with a reducing agent such as hydrazine and sodium borohydride is preferred. The amount of the reducing agent is preferably 1 to 1000 parts by weight, more preferably 10 to 500 parts by weight, and still more preferably 50 to 300 parts by weight with respect to 100 parts by weight of the flaky carbon oxide. Moreover, when it heats at the time of reduction | restoration, it will become easier to reduce | restore. The heating temperature is preferably 40 to 200 ° C, more preferably 50 to 150 ° C, and further preferably 60 to 120 ° C. The reduction time is preferably 10 minutes to 64 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 to 24 hours. However, it is preferable that the graphene structure is not excessively destroyed.

2. Flaky carbon dispersion According to the production method of the present invention described above, desired flaky carbon can be obtained. In particular, according to the production method of the present invention, a flaky carbon dispersion in which desired flaky carbon is dispersed can be obtained.

  The flaky carbon obtained in this manner is excellent in various physical properties as it is thin, but flaky carbon having a thickness of 10 nm or less, particularly 0.3 to 5 nm can be obtained. Although flaky carbon having a very large thickness may be obtained, the thickness of many flaky carbon is within the above range.

  The flaky carbon obtained in this way is excellent in various physical properties as it is thin, but flaky carbon having a layered structure in which ten or fewer layers (that is, 1 to 10 layers) of graphene are laminated can be obtained. Although flaky carbon having a very large number of layers may be obtained, the number of flaky carbon layers is within the above range. Since such flaky carbon has a planar shape with many convex angles and concave angles, its size cannot be defined unconditionally. In the present specification, the distance between the convex angles that are farthest in one piece of flaky carbon is defined as the size of the flaky carbon.

  As such flaky carbon, carbon having a size of 20 nm or more, preferably 100 nm or more, more preferably 200 nm or more can be obtained. Such a flaky carbon can provide sufficient conductivity. In addition, since it is known that the larger flaky carbon is better in various physical properties such as electrical properties, the upper limit of the size is not limited. The size of the flaky carbon is measured by observation with a microscope (such as a laser microscope).

  According to the production method of the present invention, the flaky carbon can be obtained as a flaky carbon dispersion. In the production method of the present invention, since a compound having a fluorene skeleton is included, the flaky carbon dispersion also includes a compound having a fluorene skeleton. Since this compound can be adsorbed on the surface of the flaky carbon and disperse the flaky carbon in a high concentration in a solvent, it also functions as a dispersant in the flaky carbon dispersion. Moreover, the said compound can use a commercial item, and has an advantage over the conventional product in both cost and dispersibility. Furthermore, even if this compound remains on the surface of the flaky carbon, it can maintain sufficient conductivity, and there is an advantage that this compound can be easily removed from the flaky carbon.

  In addition, in the conventional method of performing oxidation treatment and reduction treatment, the plastic substrate is hydrolyzed during the reduction treatment, and flaky carbon aggregates when subjected to the reduction treatment, so that it cannot exist as a dispersion. From the above, it was impossible to form a flaky carbon dispersion on a plastic substrate, but in the present invention, by performing a specific treatment while containing the above compound, a plastic such as polyethylene terephthalate (PET) is used. It is also possible to form a flaky carbon dispersion on a substrate without the substrate undergoing hydrolysis. Further, as described above, the separation and purification of the flaky carbon from the flaky carbon dispersion is easy, and the flaky carbon can be uniformly mixed with other materials. Applicable to. Further, the flaky carbon composition which is a dried product of the flaky carbon dispersion has a compound having a fluorene skeleton in addition to having excellent physical properties such as conductivity even if it contains a compound having a fluorene skeleton. Can be easily removed, so it can be applied to various applications such as conductive materials, heat transfer materials, power storage devices such as transistors and capacitors, sensors, piezoelectric materials, antibacterial materials, filtration materials, resin additives, optical materials, etc. .

3. Flaky carbon composition and flaky carbon In the present invention, the flaky carbon composition is a dried product of the flaky carbon dispersion, and contains a flaky carbon and a compound having a fluorene skeleton. There is no restriction | limiting in particular as a shape of such a flaky carbon composition, A coating film, a sheet | seat, a lump, etc. can be mentioned.

  In order to obtain a dried product, in addition to drying the flaky carbon dispersion, a method of drying the flaky carbon dispersion on a substrate after spin coating or coating, the flaky carbon composition is recovered by ordinary solid-liquid separation. It can be implemented by a method or the like. As a method of performing this separation, for example, a method used for usual solid-liquid separation, for example, a method of filtering using a filter paper, a glass filter or the like; a method of filtering after centrifugation; a method of using a vacuum filter Can be illustrated. Next, it does not specifically limit as a drying method, For example, the method of drying for about 1 to 24 hours at about 50-200 degreeC using a warm air dryer etc. can be illustrated.

  The flaky carbon composition thus obtained has not only sufficient conductivity but also excellent gas barrier properties. The composition of the obtained flaky carbon composition is not particularly limited. For example, the content of the compound having a fluorene skeleton is 1 part by weight or more, preferably 10 to 10,000 parts by weight with respect to 100 parts by weight of the flaky carbon. More preferably, it may be 100 to 1000 parts by weight.

  In the present invention, the flaky carbon composition may have various physical properties such as electrical conductivity even if a compound having a fluorene skeleton remains on the flaky carbon surface. Can be removed. Specifically, the compound having a fluorene skeleton can be removed by washing the flaky carbon composition with water, an organic solvent or the like. The washing treatment can be removed by washing with a dilute acid or dilute alkali in addition to water and an organic solvent. In addition, when the compound having a fluorene skeleton is an organic ammonium salt, the organic ammonium salt is decomposed by heat treatment at 150 to 400 ° C., preferably 200 to 350 ° C. Therefore, the compound having a fluorene skeleton should also be removed by heat treatment. Can do.

  Conventional dispersants are many types of surfactants used in so-called detergents. These are thought to be adsorbed by utilizing the hydrophobic interaction between dispersant molecules and flaky carbon, and the molecular weights are compared. Therefore, it is thought that its adsorption power is also large. On the other hand, since the compound having a fluorene skeleton used in the present invention is adsorbed by utilizing π-π interaction with flaky carbon, it can only be adsorbed in an aqueous medium and has a low molecular weight. Compared with weak adsorption power. Therefore, the compound having a fluorene skeleton used in the present invention has an advantage that it is easier to remove from the flaky carbon composition than the conventional product.

  Cleaning for removing the compound having a fluorene skeleton can be performed by bringing the flaky carbon composition into contact with a cleaning liquid. As the cleaning liquid, water, various organic solvents, and the like can be used as long as they can dissolve a compound having a fluorene skeleton. As the organic solvent, for example, alcohols such as methanol, ethanol, isopropyl alcohol (IPA) (particularly lower alcohols having 1 to 6 carbon atoms), acetone, N-methylpyrrolidone, dimethylformamide and the like can be used. These may be used alone or in combination of two or more.

  Among these, an organic solvent that evaporates from the flaky carbon composition in a short time after washing is preferable. Examples of the organic solvent include those having a boiling point at normal pressure of about 50 to 250 ° C., particularly about 60 to 200 ° C., such as methanol, ethanol, acetone, N-methylpyrrolidone, dimethylformamide and the like.

  In addition, as described above, the cleaning for removing the compound having a fluorene skeleton may be performed by contacting the flaky carbon composition with a dilute acid or dilute alkali and then washing with water. The diluted acid is preferably 0.1 to 5% hydrochloric acid, and the diluted alkali is preferably 0.1 to 3% aqueous ammonia.

  The cleaning operation may be performed by bringing the cleaning liquid into contact with the flaky carbon composition. For example, it is preferable that the flaky carbon composition recovered from the flaky carbon dispersion is gently immersed in the cleaning liquid at room temperature. The immersion time is preferably within 30 minutes, and more preferably within 20 minutes in order to maintain the shape of the flaky carbon composition.

  The amount of the cleaning liquid used is not particularly limited as long as it is an effective amount for cleaning, and can be appropriately selected from a wide range. In general, the cleaning liquid is 100 to 100000 parts by weight with respect to 100 parts by weight of the flaky carbon composition. Good results are obtained when about 1 part, especially about 1000 to 5000 parts by weight is used.

  Thus, the flaky carbon can be isolated, and the flaky carbon obtained at this time has the characteristics as described above.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples.

Example 1
100 g of 25 wt% tetramethylammonium hydroxide is added to 10 g of 9,9-bisphenolfluorene (9,9-bis (4-hydroxyphenyl) fluorene), and water is added to make a total of 1000 g to obtain a transparent solution. It was.

Experimental example 2
100g of 25wt% tetramethylammonium hydroxide is added to 10g of 9,9-bisnaphtholfluorene (9,9-bis [6- (2-hydroxynaphthyl)] fluorene), and water is added to make a total of 800g . Further, 200 g of ethanol was added to obtain a transparent solution having a yellowish brown color.

Experimental Example 3
A yellowish transparent solution was obtained in the same manner as in Experimental Example 2, except that 200 g of a 20 wt% aqueous sodium hydroxide solution was added instead of 100 g of 25 wt% tetramethylammonium hydroxide.

  As in Experimental Examples 1 to 3, in a fluorene compound having a phenolic hydroxyl group, a solution containing water as a main component could be obtained by substituting the proton of the phenolic hydroxyl group.

Example 1
To 100 g of the solution obtained in Experimental Example 2, 1 g of natural graphite (manufactured by Nippon Graphite Industry Co., Ltd.) was added, and a dispersion treatment for 5 minutes was added using a 600 W ultrasonic dispersion device.

  This liquid was sandwiched between two silicon wafers set in parallel with a radius of 75 mm (0 ° angle), and subjected to shear treatment at 2600 rpm for 5 minutes on a vibration mixer while applying a load of about 3 kg. A dispersion of the material was obtained. The shortest distance between two silicon wafers is the thickness of the natural graphite solution, and there is no void.

  100 g of ethanol was added to this dispersion, and ultrasonic dispersion was performed for 2 minutes, followed by filtration under reduced pressure. Acetone was added to this wet carbonaceous material, and after ultrasonic dispersion, the dispersion was applied to conductive glass and observed with a scanning electron microscope (SEM) and atomic force microscope (AFM). A carbon was obtained. Most of the flaky carbon had 1 to 10 layers, the majority had a thickness of 5 nm or less, and the flake size (size) was 1 to 20 μm. At the same time, it was confirmed that the fluorene compound was removed by washing with ethanol.

Example 2
1 g of artificial graphite (manufactured by Showa Denko KK) was added to 100 g of the solution obtained in Experimental Example 2, and a dispersion treatment for 5 minutes was added using a 600 W ultrasonic dispersion device.

  This liquid was sandwiched between two silicon wafers set in parallel with a radius of 75 mm (0 ° angle), and subjected to shear treatment at 2600 rpm for 5 minutes on a vibration mixer while applying a load of about 3 kg. A dispersion of the material was obtained. The shortest distance between two silicon wafers is the thickness of the natural graphite solution, and there is no void.

  100 g of ethanol was added to 1 g of this dispersion, and ultrasonic dispersion was performed for 2 minutes, followed by filtration under reduced pressure. Acetone was added to this wet carbonaceous material, and after ultrasonic dispersion, the dispersion was applied to conductive glass and observed with a scanning electron microscope (SEM) and atomic force microscope (AFM). A carbon was obtained. Most of the flaky carbon had 1 to 10 layers, the majority had a thickness of 5 nm or less, and the flake size (size) was 1 to 10 μm. At the same time, it was confirmed that the fluorene compound was removed by washing with ethanol. An SEM photograph of the obtained flaky carbon is shown in FIG.

Example 3
To 100 g of the solution obtained in Experimental Example 2, 1 g of expanded graphite (manufactured by Ito Graphite Industries Co., Ltd.) was added, and a dispersion treatment for 5 minutes was added using a 600 W ultrasonic dispersion apparatus.

  This liquid was sandwiched between two silicon wafers set in parallel with a radius of 75 mm (0 ° angle), and subjected to shear treatment at 2600 rpm for 5 minutes on a vibration mixer while applying a load of about 3 kg. A dispersion of the material was obtained. The shortest distance between two silicon wafers is the thickness of the natural graphite solution, and there is no void.

  100 g of ethanol was added to 1 g of this dispersion, and ultrasonic dispersion was performed for 2 minutes, followed by filtration under reduced pressure. Acetone was added to this wet carbonaceous material, and after ultrasonic dispersion, the dispersion was applied to conductive glass and observed with a scanning electron microscope (SEM) and atomic force microscope (AFM). A carbon was obtained. Most of the flaky carbon had 1 to 10 layers, the majority had a thickness of 5 nm or less, and the flake size (size) was 1 to 20 μm. At the same time, it was confirmed that the fluorene compound was removed by washing with ethanol.

Example 4
To 100 g of the solution obtained in Experimental Example 2, 1 g of natural graphite (manufactured by Nippon Graphite Industry Co., Ltd.) was added and stirred for 5 minutes with a magnetic stirrer.

  When this liquid was sheared seven times with an electric mortar rotating at 2000 rpm (shortest distance: 70 μm), a carbonaceous material dispersion was obtained.

  100 g of ethanol was added to 10 g of this dispersion, and ultrasonic dispersion was performed for 2 minutes, followed by filtration under reduced pressure. Acetone was added to this wet carbonaceous material, and after ultrasonic dispersion, the dispersion was applied to conductive glass and observed with a scanning electron microscope (SEM) and atomic force microscope (AFM). A carbon was obtained. Most of the flaky carbon had 1 to 10 layers, the majority had a thickness of 5 nm or less, and the flake size (size) was 1 to 10 μm. At the same time, it was confirmed that the fluorene compound was removed by washing with ethanol. An SEM photograph of the obtained flaky carbon is shown in FIG.

  This dispersion was dried at 150 ° C. for 24 hours to obtain a black solid containing about 50% by weight of carbon. When 20% by weight of this solid was added to polycarbonate and kneaded at 280 ° C., black pellets in which carbon was well dispersed were obtained.

  In this way, without using tape peeling, high-cost CVD, etc., and without destroying the aromatic ring structure of the carbon-based material using a strong oxidizing agent or performing its reduction process, it is extremely advanced It was possible to produce high-purity carbon that was thinly sliced by a method that can be easily mass-produced. In this method, the direction in which the force is applied is parallel to the surface direction of the graphite, and the process is performed in a narrow space. It was possible to obtain exfoliated carbon of the size (width direction) efficiently and in a short time.

  The exfoliated carbon could be obtained in the form of a dispersion, and could also be isolated without a troublesome process such as peeling it from the substrate or tape.

Claims (15)

A method for producing flaky carbon,
Between a rotating rotating disk and a disk installed substantially parallel to the rotating disk,
A composition comprising a carbonaceous material having a layered structure and a compound having a fluorene skeleton;
A manufacturing method comprising a step of applying shear to the carbonaceous material in the composition while adjusting the shortest distance between the rotating disk and the disk to be 200 μm or less. The manufacturing method according to claim 1, wherein the step of applying shear is a step of rotating the rotating disk. The manufacturing method according to claim 1 or 2, wherein the composition further contains a solvent. The production method according to claim 3, wherein the solvent contains water, and the content of the water is 60% by weight or more in the solvent. The production method according to claim 1, wherein the compound having a fluorene skeleton is a water-soluble compound having a fluorene skeleton. The production method according to claim 1, wherein the compound having a fluorene skeleton is an organic ammonium salt, an alkali metal salt, an ammonium salt, or an alkylene oxide adduct of the compound having a fluorene skeleton. The compound having a fluorene skeleton is represented by the general formula (1):
[Wherein, Z ¹ and Z ² are the same or different and each represents an aromatic hydrocarbon ring. R ^1a and R ^1b are the same or different and each represents a hydrocarbon group, an alkoxy group, a halogen atom, a nitro group, a cyano group, or an optionally substituted amino group. R ^2a and R ^2b are the same or different and each represents an alkylene group. R ^3a and R ^3b are the same or different and are hydrocarbon group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, alkoxycarbonyl group, halogen atom, nitro group, cyano group or substituted. May represent a good amino group. m1 and m2 are the same or different and represent an integer of 0 or more. p1 and p2 are the same or different and represent an integer of 1 or more. h1 and h2 are the same or different and represent an integer of 0 to 4. j1 and j2 are the same or different and represent an integer of 0 to 4. ]
The production method according to any one of claims 1 to 6, which is an organic ammonium salt, an alkali metal salt, an ammonium salt, or an alkylene oxide adduct of a fluorene compound represented by the formula: In the said General formula (1), Z < ¹ > and Z < ² > are the same or different, The manufacturing method of Claim 7 which is a benzene ring or a naphthalene ring. The production method according to claim 7 or 8, wherein m1 and m2 are both 0 in the general formula (1). The production method according to any one of claims 7 to 9, wherein the compound having a fluorene skeleton is an organic ammonium salt and / or an alkali metal salt of the compound represented by the general formula (1). The manufacturing method according to any one of claims 1 to 10, wherein the step of applying the shear is performed while adjusting the shortest distance between the rotating disk and the disk to be 50 µm or less. The manufacturing method according to claim 1, wherein an axis perpendicular to the rotating disc and an axis perpendicular to the disc are parallel. The manufacturing method in any one of Claims 1-12 whose content of the carbonaceous material which has a layered structure in the said composition is 20 weight% or less. The manufacturing method in any one of Claims 3-13 provided with the process of drying a solvent after the process of adding the said shear. A method for producing flaky carbon, comprising a step of removing a compound having a fluorene skeleton by washing the flaky carbon obtained by the production method according to claim 1 with water or an organic solvent.