JP7449110B2 - Modified graphene, method for producing modified graphene, modified graphene resin composite, modified graphene sheet, and modified graphene dispersion - Google Patents

Description

The present disclosure relates to modified graphene, a method for producing modified graphene, a modified graphene resin composite, a modified graphene sheet, and a modified graphene dispersion.

Carbon materials such as graphene, graphite, and carbon nanotubes each have excellent electrical, thermal, optical, and mechanical properties, and are expected to have a wide range of applications in areas such as battery materials, energy storage materials, electronic devices, and composite materials. There is. In order to make the characteristics of these various carbon materials function effectively and use them industrially, it may be necessary to control the cohesive force of the carbon materials and improve their dispersibility in a dispersion medium.
As a method for suppressing cohesive force, a manufacturing method is known in which the surface of a carbon material is chemically treated and a substituent is introduced to modify the surface.
Patent Document 1 describes a method for producing graphene oxide in which an oxygen-containing group is introduced onto the surface of graphene by the Hummers method using graphite and an oxidizing agent. Further, Patent Document 3 describes a method for producing graphene powder having an amino group by reacting graphite powder with a processing agent having an amino group (-NH ₂ ), such as a monodiazonium salt of p-phenylenediamine, in water. is disclosed.

Patent No. 5098064 JP 2016-27092 Publication Patent No. 3980637 JP 2016-27093 Publication

Journal of the American Chemical Society, 76, 1283-1285 (1954)

One aspect of the present disclosure is directed to providing modified graphene that has improved dispersibility in a dispersion medium without impairing the excellent electrical conductivity and thermal conductivity that graphene inherently has.
Another aspect of the present disclosure is directed to providing a method for producing modified graphene that has excellent dispersibility in a dispersion medium without impairing the excellent electrical conductivity and thermal conductivity that graphene inherently has. .
Further, another aspect of the present disclosure is directed to providing a modified graphene resin composite, a modified graphene sheet, and a modified graphene dispersion that have excellent electrical conductivity and thermal conductivity.

According to one aspect of the present disclosure, modified graphene has a structure represented by the following formula (I), and has a ratio (g/d) of G band intensity g and D band intensity d in a Raman spectroscopic spectrum. is 1.0 or more:
Gr1-Ar1-X1-(Y1)n1 (I)

In the formula (I),
Gr1 is single layer graphene or multilayer graphene,
Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

で置き換えた基である場合は、該基中の酸素原子、または窒素原子に結合する原子または基であり、
Ｘ１が炭素数１のアルキレン基中の１つの炭素原子を、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基である場合、及び、
Ｘ１が炭素数２～２０の直鎖状、分岐鎖状もしくは環状のアルキレン基中の少なくとも１つの炭素原子を、－Ｏ－、－ＮＨ－、 -CO-, -COO-, -CONH-, and a group substituted with at least one structure selected from the group consisting of an arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom in Ar1,
When X1 is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, it is an atom or group bonded to a carbon atom in the alkylene group,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, as well as,
X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, -O-, -NH-,

In the case of a group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, an atom bonded to a carbon atom or a nitrogen atom in the group or Based on
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups.

According to another aspect of the present disclosure, a method of manufacturing modified graphene, comprising:
A compound represented by the following formula (V) is subjected to a radical addition reaction by abstracting hydrogen atoms from the compound in a liquid medium in the presence of an oxidizing agent at a temperature of -5°C or higher and 80°C or lower. , has a bonding step of bonding a group represented by A1 in the following formula (V) to a carbon atom on the surface of graphene as a raw material ,
A method for producing modified graphene is provided , in which the oxidizing agent has an oxidation potential of +0.50 V or more and +1.70 V or less .
HN=N-A1 (V).
(In the above formula (V),
A1 is a group represented by -Ar1-X1-(Y1)n1,
Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

で置き換えた基である場合は、該基中の酸素原子、または窒素原子に結合する原子または基であり、
Ｘ１が炭素数１のアルキレン基中の１つの炭素原子を、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基である場合、及び、Ｘ１が炭素数２～１０の直鎖状、分岐鎖状もしくは環状のアルキレン基中の少なくとも１つの炭素原子を、－Ｏ－、－ＮＨ－、

－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基である場合は該基中の炭素原子、又は窒素原子に結合する原子または基であって、
該Ｙ１は、
水素原子、フッ素原子、塩素原子、臭素原子、ヨウ素原子、
炭素数１～６のフルオロアルキル基、
シアノ基、ニトロ基、アシル基、アミド基、ビニル基、カルボン酸基、カルボン酸エステル基、リン酸基、
炭素数３～６のアルキルシリル基、
炭素数３～６のアルキルシリルエーテル基、及び
シロキサン基
からなる群から選択される少なくとも１つの原子または基であり、
ｎ１は１以上の整数を表し、ｎ１が２以上の場合、Ｙ１は互いに同じ基であっても、異なる基であっても良い。）。 -CO-, -COO-, -CONH-, and a group substituted with at least one structure selected from the group consisting of an arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom in Ar1,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, and X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 10 carbon atoms, -O-, -NH-,

-CO-, -COO-, -CONH-, and an atom or group bonded to a carbon atom or nitrogen atom in the group in the case of a group substituted with at least one structure selected from the group consisting of an arylene group. And,
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups. ).

According to other aspects of the disclosure:
At least one treatment agent selected from the group consisting of a compound represented by the following formula (IX) and a compound represented by the following formula (X) is applied at a pH of 1.5 to 7 and a temperature of 5 to 80°C. A method for producing modified graphene , comprising a step of reacting graphene as a raw material to chemically bond a group represented by A1 in the formula (IX) or the formula (X) to a carbon atom on the surface of the graphene. provided:

(In the above formula (IX),
P ₁ , P ₂ , and P ₃ each independently represent a hydrogen atom, an alkyl group, an aryl _group , a carboxylic acid ester group, or _-S (=O) ₂ -R'; All ₃ cannot become hydrogen atoms at the same time.
R' represents a hydroxy group, an alkyl group, or an aryl group.
A1 is a group represented by -Ar1-X1-(Y1)n1.

In the formula (X),
Q ₁ and Q ₂ are each independently a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, an amino group, an alkoxy group, a thioalkoxy group, an acyl group, a carboxylic acid ester group, an aryloxy group, It represents a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, or a phosphonic acid group, and Q ₁ and Q ₂ are never hydrogen atoms at the same time.
Q ₃ represents a hydrogen atom, an alkyl group, an aryl group, or a carboxylic acid ester group. A1 is a group represented by -Ar1-X1-(Y1)n1.

The Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基であり、
Ｙ１は、
Ｘ１が単結合である場合は、Ａｒ１中の少なくとも１つの炭素原子に結合する原子もしくは基であり、
Ｘ１が炭素数１～２０の直鎖状、分岐鎖状もしくは環状のアルキレン基である場合は、該アルキレン基中の炭素原子に結合する原子もしくは基であり、
Ｘ１が炭素数１のアルキレン基中の１つの炭素原子を、－Ｏ－、－ＮＨ－、または

で置き換えた基である場合は、該基中の酸素原子、または窒素原子に結合する原子または基であり、
Ｘ１が炭素数１のアルキレン基中の１つの炭素原子を、－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基である場合、及び、
Ｘ１が炭素数２～２０の直鎖状、分岐鎖状もしくは環状のアルキレン基中の少なくとも１つの炭素原子を、－Ｏ－、－ＮＨ－、

A group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom in Ar1,
When X1 is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, it is an atom or group bonded to a carbon atom in the alkylene group,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, as well as,
X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, -O-, -NH-,

－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、アリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基である場合は、該基中の炭素原子、又は窒素原子に結合する原子または基であって、
該Ｙ１は、
水素原子、フッ素原子、塩素原子、臭素原子、ヨウ素原子、
炭素数１～６のフルオロアルキル基、
シアノ基、ニトロ基、アシル基、アミド基、ビニル基、カルボン酸基、カルボン酸エステル基、リン酸基、
炭素数３～６のアルキルシリル基、
炭素数３～６のアルキルシリルエーテル基、及び
シロキサン基
からなる群から選択される少なくとも１つの原子または基であり、
ｎ１は１以上の整数を表し、ｎ１が２以上の場合、該Ｙ１は互いに同じ基であっても、異なる基であっても良い。）。

In the case of a group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene groups, an atom or group bonded to a carbon atom or nitrogen atom in the group And,
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups. ).

According to other aspects of the present disclosure, a modified graphene resin composite, a modified graphene sheet, and a modified graphene dispersion containing modified graphene having a structure represented by the above formula (I) are provided.

According to one aspect of the present disclosure, it is possible to provide modified graphene that has excellent electrical conductivity and thermal conductivity, and has functional groups introduced onto its surface. Further, according to another aspect of the present disclosure, it is possible to provide a method for producing modified graphene that has excellent electrical conductivity and thermal conductivity and has functional groups introduced onto the surface. Furthermore, according to other aspects of the present disclosure, a modified graphene resin composite containing modified graphene having excellent electrical conductivity and thermal conductivity and having a functional group introduced onto the surface, a modified graphene sheet, and A modified graphene dispersion can be provided.

A diagram showing a reaction mechanism when obtaining modified graphene. The figure which shows the reaction mechanism when the compound shown by Formula (IX) is used as a processing agent. Chart of Raman spectra of modified graphene and unmodified graphene.

The present inventors investigated chemical modification of graphene in order to obtain graphene with excellent dispersibility in a dispersion medium without impairing graphene's inherent high electrical conductivity and thermal conductivity.
According to the study, in the method described in Patent Document 1, functional groups are introduced onto the graphene surface together with a strong oxidizing agent, so graphene may be oxidized and the sp ² structure unique to graphene may be destroyed. There was found.

Furthermore, in the method described in Patent Document 3, the diazonium compound is easily decomposed and the generation of radicals cannot be controlled within the reaction system, so it is thought that a large amount of radicals are generated in a short period of time. As a result, it was found that the sp ² structure unique to graphene may be destroyed. When the sp2 structure unique to graphene is destroyed, it is thought that the excellent electrical conductivity and thermal conductivity originally possessed by graphene will be impaired.

On the other hand, Patent Document 2 and Patent Document 4 disclose methods for producing self-dispersing pigments. However, Patent Document 2 and Patent Document 4 do not disclose or suggest the applicability of the production method to graphene.

Under these circumstances, the present inventors conducted further studies and found that graphene has excellent dispersion in a dispersion medium without sacrificing its inherent excellent properties, such as high electrical conductivity and excellent thermal conductivity. We have discovered modified graphene that exhibits properties.

That is, the modified graphene according to the present disclosure has a structure represented by the following formula (I), and the ratio (g/d) of the G band intensity g and the D band intensity d in the Raman spectrometer is 1.0. That's all:
Gr1-Ar1-X1-(Y1)n1 (I).

Gr1, Ar1, X1, Y1 and n1 in formula (I) will be explained.

Gr1 represents single layer graphene or multilayer graphene.
Ar1 is an arylene group having 6 to 18 carbon atoms.
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

A group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group.
When X1 is a single bond, Y1 is an atom or group bonded to at least one carbon atom in Ar1 (arylene group).
Further, when X1 is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, Y1 is an atom or group bonded to a carbon atom in the alkylene group.
Furthermore, X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, -O-, -NH-,

When the group is substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, Y1 is an atom or group bonded to a carbon atom in the group. .

Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms and a siloxane group.
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups.
The modified graphene according to the above formula (I) can also be said to have -Ar1-X1-(Y1)n1 bonded as a modifying group to at least one of the carbon atoms constituting graphene.

Furthermore, the G band of graphene in the Raman spectroscopic spectrum is one of the characteristic peaks of graphene, and is a peak that originates from the in-plane motion of carbon atoms and appears around 1580 to 1590 cm ⁻¹ . On the other hand, the D band of graphene in the Raman spectrum is a peak that appears around 1350 cm ⁻¹ due to disorder and defects in the structure of graphene.
Normally, even unmodified graphene has structural disturbances and defects, but the ratio (g/d) of the G band intensity g to the D band intensity d is less than 1.0. It won't happen. The technical meaning of the modified graphene according to the present disclosure having (g/d) of 1.0 or more is that even after chemical modification, structural disorder and defects in graphene increase. This is something I have not done.

That is, FIG. 3(c) shows a chart of the Raman spectra of graphene ("xGnP-M5"; manufactured by Niimetals Endo Chemicals Corporation) before chemical modification used in the Examples described below. The ratio (g/d) between the intensity g of the G-band peak 501 and the intensity d of the D-band peak 502 of graphene is 1.0.
As shown in FIG. 3(a), the modified graphene obtained by introducing a modifying group into graphene by a method according to an embodiment of the present disclosure described below has an intensity g of the G-band peak 301 that is lower than that of the D-band. The intensity was greater than the intensity d of peak 302, and (g/d) was 1.1.

On the other hand, as described in Patent Document 1, in modified graphene into which a modifying group is introduced by the Hummers method, the intensity d of the D-band peak 402 is the same as the G-band peak It was stronger than the strength g of 401, and (g/d) was 0.7.
This is presumably because, as described above, the sp ² structure unique to graphene was destroyed in the oxidation method.
As mentioned above, the modified graphene according to the present disclosure is modified without destroying the original structure of graphene or creating defects in the structure, and it can be dispersed without impairing the original properties of graphene. It can be said that functionality such as good dispersibility in media is imparted.
(g/d) in the modified graphene according to the present disclosure is preferably 1.1 or more.

In formula (I), the arylene group for Ar1 is not particularly limited, and examples thereof include the following. Phenylene group, biphenylene group, triphenylene group, naphthalene group, anthracene group, etc.

Further, in formula (I), the linear, branched, or cyclic alkylene group having 1 to 20 carbon atoms in X1 is not particularly limited, but examples include the following. Methylene group, ethylene group, n-propylene group, iso-propylene group, n-butylene group, sec-butylene group, tert-butylene group, octylene group, dodecylene group, nonadecylene group, cyclobutylene group, cyclopentylene group, cyclohexyl group Primary to tertiary alkylene groups such as silene group, methylcyclohexylene group, 2-ethylpropylene group, 2-ethylhexylene group, etc.

In addition, in formula (I), at least one carbon atom in the linear, branched or cyclic alkylene group having 1 to 20 carbon atoms in X1 is replaced by -O-, -NH-,

The group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group is not particularly limited, but examples include the following: . When one of the carbon atoms constituting an ethylene group is replaced with -O-, it becomes a methyl ether group, and when one of the carbon atoms constituting a propylene group is replaced with -O-, it becomes an ethyl ether group. Become.

In formula (I), the acyl group in Y1 is not particularly limited, and examples thereof include formyl group, acetyl group, propionyl group, benzoyl group, and acrylic group.
Further, in formula (I), the amide group in Y1 is not particularly limited, but is a group represented by -CONR'R'', and examples thereof include the following.
Both R' and R'' are carboxylic acid dialkylamide groups such as methyl group, ethyl group, propyl group, butyl group,
Either R' or R'' is a carboxylic acid monoalkylamide group such as a methyl group, ethyl group, propyl group, or butyl group,
An acetamide group where both R' and R'' are H, etc.

Further, in formula (I), the vinyl group in Y1 is not particularly limited, but for example, in addition to an unsubstituted vinyl group, a substituted vinyl group may be used, such as a butylene group, a vinyl acetate group, a butyl vinyl ether group, etc. , an acrylic group, a methacrylic group, a styrene group, and the like.
Further, in formula (I), the carboxylic acid ester group in Y1 is not particularly limited, but examples thereof include the following. Methoxycarbonyl group, ethoxycarbonyl group, isopropyloxycarbonyl group, propoxycarbonyl group, cyclohexyloxycarbonyl group, etc.

Further, in formula (I), specific examples of the alkylsilyl group having 3 to 6 carbon atoms in Y1 include trimethylsilyl group and triethylsilyl group.
Furthermore, the siloxane group in Y1 is a group having the following structure.

In formula (I), the substituent on Si of the siloxane group in Y1 is not particularly limited, but is preferably an alkyl group, a cycloalkyl group, or an aryl group. The alkyl group and aryl group are the same as described above. Specific examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group. Specific examples of the siloxane group include trimethylsiloxane group, triethylsiloxane group, phenyl-dimethylsiloxane group, and cyclopentyl-dimethylsiloxane group.

In addition, since the siloxane groups of the following formulas (II), (III), and (IV) have large molecular weights, they are used for the purpose of preventing graphene from aggregating with each other or improving the compatibility between graphene and resin. It can be used suitably.

In formulas (II) to (IV), R ₁ to R ₂₃ each independently represent an alkyl group, an amino group, a vinyl group, a carboxylic acid ester group, a carboxylic acid group, a hydroxy group, or an aryl group, and L1 is 1 to It represents an integer of 6, and L2 and (L3+L4) are numbers from 0 to 650.
Specific examples of the alkyl group, vinyl group, carboxylic acid ester group, and aryl group are the same as those described above.
The amino group is a group having the following structure, and the two substituents on N are hydrogen atoms or alkyl groups. Specific examples of the alkyl group are the same as above.

When Y1 in formula (I) is a group, the number of moles of the group per 1 g of modified graphene is preferably 0.10 mmol or more and 1.20 mmol or less.
By setting the number of moles of the group to 1 g of modified graphene to be 0.10 mmol or more, repulsion (repulsive force) between the modified graphenes can be ensured. As a result, when the modified graphene according to the present disclosure is dispersed in a medium or a resin, formation of aggregates (agglomerates) due to van der Waals forces between modified graphenes can be suppressed. Further, by setting the number of moles of the group to 1.20 mmol or less, it is possible to suppress a decrease in heat propagation between the modified graphenes due to the modified graphene being coated with the modifying group. As a result, a decrease in thermal conductivity of the modified graphene dispersion according to the present disclosure can be suppressed.

Preferred specific examples of the modified graphene according to the present disclosure represented by the following formula (I) are shown below. Note that Gr1 (graphene) in formula (I) is omitted, and only the structure *Ar1-X1-(Y1)n1 is described. The * above means a bonding site with a carbon atom constituting Gr1.
Gr1-Ar1-X1-(Y1)n1 (I)

(Specific example of modified graphene)
A1-1 to A1-90 are listed below as specific examples of modified graphene, but the invention is not limited to the following examples.

Examples where Ar1 is a phenylene group, X1 is a single bond, Y1 is a carboxylic acid group, and n1 is 1 to 6 include A1-22, A1-23, A1-24, and A1-25. do.

または－ＣＯＮＨ－で置き換えた基であり、Ｙ１がリン酸基であり、ｎ１が１～４である例としては、Ａ１－５７が該当する。 Ar1 is a phenylene group, X1 is at least one carbon atom in a branched alkylene group having 1 to 20 carbon atoms,

A1-57 is an example of a group substituted with -CONH-, Y1 is a phosphoric acid group, and n1 is 1 to 4.

Examples in which Ar1 is a phenylene group, X1 is a single bond, Y1 is a nitro group, and n1 is 1 to 3 include A1-10, A1-11, and A1-12.

－ＣＯ－または－ＣＯＮＨ－で置き換えた基であり、Ｙ１が水素原子またはビニル基であり、ｎ１が１～３である例としては、Ａ１－１３、Ａ１－１４、Ａ１－１５が該当する。 Ar1 is a phenylene group, X1 is at least one carbon atom in a branched alkylene group having 1 to 20 carbon atoms,

Examples of a group substituted with -CO- or -CONH-, where Y1 is a hydrogen atom or a vinyl group, and n1 is 1 to 3 include A1-13, A1-14, and A1-15.

Modified graphene having the structure represented by formula (I) can be synthesized, for example, by the method detailed below.

<Method for producing modified graphene (1)>
A first aspect of the method for producing modified graphene according to the present disclosure is a radical addition reaction by abstracting a hydrogen atom from a compound represented by the following formula (V) in an aqueous system. The method includes a bonding step of bonding the group to the carbon atom on the graphene surface.
HN=N-A1 (V)

In formula (V), A1 is a group represented by -Ar1-X1-(Y1)n1. Ar1 is an arylene group having 6 to 18 carbon atoms.
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

－ＣＯ－、－ＣＯＯ－、－ＣＯＮＨ－、及びアリーレン基からなる群から選択される少なくとも１つの構造で置き換えた基から選択されるいずれかである。

-CO-, -COO-, -CONH-, and a group substituted with at least one structure selected from the group consisting of an arylene group.

Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom in Ar1,
When X1 is not a single bond, an atom or group bonded to the carbon atom of X1,
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms and a siloxane group.
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups.

The method for producing modified graphene according to this embodiment can further include a production step of producing the compound represented by the formula (V) by abstracting a hydrogen atom from the compound represented by the following formula (VI). .
H ₂ N-NH-A1 (VI)
Note that formula (V) may be referred to as a processing agent for graphene as a raw material.

For example, when manufacturing modified graphene represented by the following formula (VIII), if it is okay to increase the number of manufacturing steps, the modified graphene represented by the following formula (VII) included in formula (I) can be manufactured in advance. do. Then, this may be used as an intermediate to lead to the following formula (VIII) using a further chemical reaction. In this case, since there is a carboxylic acid group in formula (VI), the following formula (VIII) can be easily obtained by using a condensation reaction with an amine compound corresponding to the site to be further bonded.
Gr1-Ar1-COOH (VII)
Gr1-Ar1-CO-NH-CH ₂ -CH ₂ -CH ₂ -CH ₃ (VIII)

According to the production method according to this aspect, modified graphene can be produced in one pot with high reaction efficiency even at room temperature (25° C.) without selecting a reaction device or liquid medium. In particular, since the reaction efficiency is high, the amount of processing agent used for graphene can be reduced. Furthermore, high reaction efficiency also means that generation of by-products is suppressed, and purification after production is easy. Furthermore, in the manufacturing method according to the present disclosure, since a stable and safe processing agent is used, the load on the environment can also be reduced.

(graphene)
Graphene, the raw material, will be explained. Graphene is a two-dimensional sheet-like carbon compound having a structure covered with six-membered carbon rings. In the present disclosure, the material is not particularly limited as long as it has the above structure, and examples thereof include single-layer graphene, multi-layer graphene, and graphite.
Single-layer graphene refers to a sheet of sp2 ^- bonded carbon atoms that is one atom thick. Multilayer graphene refers to a laminated sheet of several layers of single-layer graphene. Graphite means a laminated sheet of more than one layer or an agglomerate of such laminated sheets. Further, the form of graphene is not particularly limited, and examples include powdery and granular forms. These materials may be commercially available products, or may be produced by conventional methods such as microwave CVD and atmospheric CVD.

As the graphene described above, for example, the following commercial products can be suitably used, but the graphene is not limited to these.
xGnP-C-750 (lateral length: 1 to 2 μm, XG Science Co., Ltd.), xGnP-H-5 (lateral length: 5 μm, XG Science Co., Ltd.), xGnP-M-5 (lateral length xGnP-R-10 (lateral length: 10 μm, XG Science Co., Ltd.), iGrafen-α (Itek Co., Ltd.), iGrafen-αS (Itek Co., Ltd.), Gi-PW-F301 ( Lateral length: 1 μm, Ishihara Chemicals), Graphene C (Kjer Graphene), Graphene Powder (Graphene Platform), Graphene Flower-GF4 (lateral length: 10 μm, Incubation Alliance), Graphene Flower-GF7 (lateral length: 1 to 3 μm, Incubation Alliance), expanded graphite EXP-50S (Fuji Graphite Industries), expanded graphite EXP-50SL (Fuji Graphite Industries), expanded graphite EC1 (Ito Graphite Industries) , 0 spherical graphite SGBH (Ito Graphite Co., Ltd.), spherical graphite SGBH8 (Ito Graphite Co., Ltd.), spheroidal graphite CGB20 (particle size: 20 μm, Nippon Graphite Industries Co., Ltd.), spheroidal graphite CGC20 (particle size: 20 μm, Nippon Graphite Industries Co., Ltd.), Graphene CVD single layer sheet (Numa Metals), etc.

(Processing agent)
Commercially available reagents can be used as the compounds represented by formula (V) and formula (VI). Furthermore, if the reagent is not commercially available, a synthesized one can also be used.
Although the synthesis method is not particularly limited, an example will be given and explained below. The synthesis method described in Formula 2 below is a method for obtaining a hydrazine compound from an amine compound. Specifically, the synthesis of 4-hydrazinobenzoic acid from 4-aminobenzoic acid will be explained as an example. Hydroxylamine o-sulfonic acid is used as a nitrogen source when adding nitrogen to an amine compound. A hydrazine compound is produced by reacting an amine compound with hydroxylamine o-sulfonic acid under alkaline conditions. If the hydrazine compound is precipitated as a salt (such as hydrochloride) by addition of an acid, the hydrazine compound can be efficiently separated by filtration or the like.

Furthermore, for example, Non-Patent Document 1 describes a method for obtaining 2-hydrazino-1-propanol from 2-amino-1-propanol using hydroxylamine o-sulfonic acid.

(Oxidant)
In the production method according to this aspect, it is preferable to produce modified graphene in the presence of an oxidizing agent. "Oxidizing agent" means "a compound that can extract hydrogen atoms and electrons from a target compound and has an oxidation potential of +0.00 V or more." Note that although an oxidizing agent can be used to improve the reaction rate, the reaction used in the production method according to this embodiment proceeds without using an oxidizing agent.

Generally, when an oxidizing agent is applied to graphene, carbon atoms on the surface of graphene particles are oxidized to become carboxylic acid groups. On the other hand, in the production method according to the present disclosure, the action of the oxidizing agent promotes the production of the compound represented by formula (V) from the compound represented by formula (VI), and the oxidative radicals that proceed subsequently The addition reaction proceeds preferentially.
Therefore, the oxidizing agent does not directly act on the graphene surface. This is because the energy (bonding energy between carbon and oxygen) required to oxidize carbon atoms on the graphene surface to lead to carbonyl species (C=O) is greater than the energy required to oxidize carbon atoms on the graphene surface to lead to carbonyl species (C=O). This is because less energy is required to extract hydrogen atoms from the That is, when the compounds represented by formulas (V) and (VI) are present, the oxidizing agent is selectively consumed for abstracting hydrogen atoms.

Examples of the oxidizing agent that can be used in the production method according to this embodiment include halogens, oxo acid compounds, metal oxides, halogenated metal compounds, metal porphyrin compounds, hexacyano metal acid compounds, metal nitrates, hydrogen peroxide, nitric acid, etc. can be mentioned.
Examples of the halogen include chlorine, bromine, and iodine.

Examples of the oxo acid compound include chromic acid, molybdic acid, permanganic acid, vanadic acid, bismuth acid, hypohalous acid, halous acid, halogen acid, perhalogen acid, and the like. Although these oxoacid compounds may form salts, they are required to contain a metal. Examples of cations that form salts include alkali metal ions and ammonium ions. Note that in an aqueous liquid, a salt can exist dissociated into ions, but for convenience, it is expressed as a "salt." Specific examples of oxoacid compounds include the following. Chromates such as potassium chromate, potassium dichromate, bis(tetrabutylammonium) dichromate, pyridinium dichromate, pyridinium chlorochromate, pyridinium fluorochromate; potassium permanganate, sodium permanganate, Permanganates such as ammonium manganate, silver permanganate, zinc permanganate, magnesium permanganate; vanadates such as ammonium vanadate, potassium vanadate, sodium vanadate; sodium bismuthate, potassium bismuthate, etc. bismuthate; hypochlorous acid, chlorous acid, perchloric acid, hypobromous acid, bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid, iodic acid, periodic acid, such as fluorite and these salts.

Examples of metal oxides include manganese oxide, lead oxide, copper oxide, silver oxide, and osmium oxide. Examples of the metal halide compound include zinc chloride, aluminum chloride, silver chloride, chromium chloride, zirconium chloride, tin chloride, cerium chloride, iron chloride, barium chloride, magnesium chloride, manganese chloride, and the like.

Examples of metal porphyrin compounds include porphyrin compounds that have a central metal and may be substituted. Specific examples include tetrabenzoporphyrin compounds, tetraazaporphyrin compounds, phthalocyanine compounds, naphthalocyanine compounds, and the like. The central metal may be any metal as long as the oxidation potential of the metal porphyrin compound is +0.00V or higher. Examples of the central metal include Fe, Co, Ni, Cu, Zn, Mg, Pt, Mn, Ru, Cr, and Pd. Further, a ligand may be present in the metal, and any known ligand may be used.

Examples of hexacyanometallic acid compounds include hexacyanoferrates and hydrates thereof. Specifically, potassium hexacyanoferrate, sodium hexacyanoferrate, ammonium hexacyanoferrate, copper hexacyanoferrate, hexacyanoferrate double salts (lithium/potassium hexacyanoferrate, etc.), and hydrates thereof can be mentioned. .
Examples of metal nitoxides include potassium nitrate, sodium nitrate, silver nitrate, copper nitrate, and the like.

In addition to the above-mentioned oxidizing agents, organic peroxides, hypervalent iodine compounds, N-oxide compounds, etc. can also be used as long as they meet the definition of "oxidizing agent" described above.
The larger the oxidation potential of the oxidizing agent, the easier it is to extract hydrogen atoms from the processing agent. The oxidizing agent that can be used in this embodiment has an oxidation potential of +0.00 V or more, but since the reaction efficiency can be improved, an oxidizing agent that has an oxidizing potential of +0.50 V or more and +1.70 V or less , more preferred. Oxidizing agents having an oxidation potential in this range include iron chloride (neutral to alkaline; +0.77V), sodium periodate (acidic; +1.20V), manganese oxide (neutral to alkaline; +1.28V), Examples include potassium permanganate (acidic; +1.51V).

The reason why the oxidation potential is involved in the reaction was speculated as follows.
Necessary for extracting a hydrogen atom from a hydrazine compound to make a diazene compound using general-purpose quantum chemical calculation software (“Gaussian 03 Revision E.01 [Structure optimization method; B3LYP/6-31G*]”; manufactured by Gaussian) The energy was calculated. As a result, it was found that the energy required to extract two hydrogen atoms was +1.00V, and the energy required to extract one hydrogen atom was +0.50V. For these reasons, by using an oxidizing agent with an oxidation potential of +0.50 V or more, hydrogen atoms can be more efficiently extracted from the hydrazine compound, and the reaction efficiency can be improved.

On the other hand, if an oxidizing agent with an oxidation potential of more than +1.70 V is used, although the reaction proceeds, the effect of drawing out hydrogen atoms, that is, the oxidizing effect becomes large, and the hydrazine compound is radicalized rapidly. In this case, since a large excess of radicals is present in the reaction system, a radical deactivation reaction (such as a homocoupling reaction between adjacent radicals) occurs. For this reason, the reaction between graphene and the processing agent is inhibited, and it may become difficult to obtain the effect of improving reaction efficiency by using an oxidizing agent. For these reasons, it is preferable that the oxidizing potential of the oxidizing agent is +1.70V or less. Among these, the oxidation potential of the oxidizing agent is more preferably +1.00V or more and +1.60V or less.

It is also preferable to use an oxidizing agent that has a catalytic effect. Among the oxidizing agents mentioned above, a metal halide compound, a metal porphyrin compound, or a hexacyano metal of at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Mg, Mn, Cr, and Mo. Acid compounds etc. have a catalytic effect. The catalytic oxidizing agent is used to extract hydrogen atoms and becomes a reducing species, and then returns to an oxidizing species under the action of oxygen in the reaction system, so that it can be used as an oxidizing agent again. Therefore, by using an oxidizing agent having a catalytic effect, the amount of oxidizing agent used can be reduced. An oxidizing agent having a catalytic action includes a metal whose valence easily changes (a metal element that can assume two or more oxidation states).

Specific examples of metal valence changes include Fe (II, III), Co (II, III), Ni (II, III), Cu (0, I, II), Mg (0, II), Mn ( II, IV, VII), Cr (II, III), Mo (IV, V), etc. The mechanism by which the catalytic action occurs will be explained using specific examples. For example, in the case of an oxidizing agent having trivalent Fe (Fe(III)), the oxidizing species Fe ³⁺ (Fe(III)) is used to extract hydrogen atoms from the hydrazine compound, and the reducing species Fe 3+ (Fe(III)) is used to extract hydrogen atoms from the hydrazine compound. ²⁺ (Fe(II)) is produced. Thereafter, it returns to the oxidizing species Fe ³⁺ (Fe(III)) under the action of oxygen in the reaction system, and can be used as an oxidizing agent again.

In the manufacturing method according to this embodiment, even when an oxidizing agent is used, its function is not impaired, so that an inert gas such as nitrogen or argon can be used. This is because the oxidative radical addition reaction is carried out not by the exchange of oxygen but by the abstraction of hydrogen atoms. Methods for introducing the inert gas into the reaction system include, for example, a method in which the inert gas is introduced from a cylinder through a tube; a method in which a gas collected in a balloon or the like is taken out from the tip of a needle and introduced into the inert gas.

(Reaction mechanism)
The reaction mechanism for obtaining modified graphene according to this embodiment will be described below. It can be assumed that the reaction according to this embodiment proceeds as an oxidative radical addition reaction, as shown in FIG. Note that the reaction mechanism shown in FIG. 1 is an example when a compound represented by the above formula (VI) is used.

First, by the action of an oxidizing agent (Fe ³⁺ ), the hydrogen atoms of the hydrazine compound shown by (1) in FIG. 1 are extracted and radically oxidized to generate a diazene compound (2). Further oxidation causes hydrogen atoms to be extracted and diazene radicals (3) to be generated. Diazene radicals instantly undergo nitrogen elimination to generate radical species (4). Then, by radical addition of the radical species (4) to the double bond on the graphene surface, the desired modified graphene (6) is obtained via the radical intermediate (5).

In the production method according to the present embodiment, when an oxidizing agent whose valency easily changes, such as potassium hexacyanoferrate (III), is used, an addition reaction other than the above may occur in parallel. In other words, the radical species (4) undergoes radical addition to the double bond on the surface of the graphene particle to generate a radical intermediate (5), and at the same time, the radical is captured by oxygen molecules to form a radical intermediate (7). occurs. In this case, after being reduced by the action of the reducing species (Fe ²⁺ ) of the oxidizing agent, modified graphene (9) to which hydroxy groups are bonded is obtained via an oxygen radical intermediate (8).
In contrast, modified graphene (9) is hardly produced using an oxidizing agent such as hypochlorous acid.
In each of the above reaction mechanisms, the diazene compound and hydrazine compound do not decompose rapidly, and radical species are generated slowly, so that the radical addition reaction to the graphene particle surface progresses efficiently. Therefore, compared to conventional manufacturing methods, according to the manufacturing method of this embodiment, modified graphene with a high amount of substituents, that is, A1 introduced, can be obtained even if the amount of treating agent used for graphene is small. .

In the technique disclosed in Patent Document 3, graphene is modified using a diazonium salt as a processing agent. However, diazonium salts are easily decomposed by the influence of alkali and temperatures exceeding room temperature (25° C.). When the diazonium salt decomposes in the reaction system, various decomposition products are generated. Therefore, reactions between the decomposed products and the liquid medium or oxygen, reactions between the decomposed products, and other side reactions are likely to occur. Therefore, when attempting to obtain modified graphene with a high amount of substituents introduced using a diazonium salt, it is necessary to use a larger amount of the diazonium salt than the graphene. However, if the amount of diazonium salt used is increased, many nitrogen gas bubbles are generated, making it difficult to increase the reaction efficiency.

In the production method according to this embodiment, the temperature may be set at a temperature other than room temperature (25° C.) in order to control the reaction rate of the radical addition reaction. If it is desired to increase the reaction rate, the temperature may be increased, and heating may be performed within a range below the reflux temperature of the liquid medium. For example, when the liquid medium is water, the temperature may be 100°C or less. Further, when the liquid medium is tetrahydrofuran, the temperature may be 80°C or lower. Further, when the liquid medium is N,N-dimethylformamide, the temperature may be lower than 160°C. However, the reaction used in the production method according to this embodiment has high reaction efficiency even at around room temperature (25° C.), so there is no need to raise the temperature too much. Further, even though it is chemically stable, it is preferable to carry out the reaction at a temperature of 80° C. or lower in consideration of thermal decomposition. On the other hand, if it is desired to lower the reaction rate, cooling may be performed so that the temperature is below room temperature (25° C.). However, since the reaction time may be long, the temperature is preferably -5°C or higher.

The manufacturing method according to this embodiment is usually performed in a liquid medium. The content (mass%) of graphene in the liquid medium is preferably 1.0% by mass or more and 50.0% by mass or less, and 5.0% by mass or more and 40.0% by mass, based on the total mass of the liquid medium. % or less is more preferable. If the content is too high, the viscosity of the reaction system will become high, making stirring difficult, which may cause a slight decrease in reaction efficiency. On the other hand, if the content is too low, the frequency of contact between the processing agent and graphene within the reaction system will decrease, and the reaction efficiency may decrease somewhat.

(post-processing)
The produced modified graphene can be used for various purposes, preferably after being subjected to a general post-treatment method such as purification. Specifically, it can be in a normal state such as a powder or pellet form in which no liquid medium is present. In this case, the liquid medium may be removed by reducing pressure or heating using an evaporator or the like, or may be removed by drying using a freeze-drying method, an oven, or the like.

<Method for producing modified graphene (2)>
A second aspect of the method for producing modified graphene according to the present disclosure includes at least one treatment agent selected from the group consisting of a compound represented by the following formula (IX) and a compound represented by the following formula (X). By reacting with graphene,
In the compound represented by formula (IX) or formula (X), there is a step of chemically bonding a group represented by A1 to a carbon atom on the surface of graphene.

In formula (IX),
P ₁ , P ₂ , and P ₃ each independently represent a hydrogen atom, an alkyl group, an aryl group, a carboxylic acid ester group, or -S(=O)2-R', and P ₁ , P ₂ , and P All ₃ cannot become hydrogen atoms at the same time.
R' represents a hydroxy group, an alkyl group, or an aryl group.
In formula (X),
Q ₁ and Q ₂ are each independently a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, an amino group, an alkoxy group, a thioalkoxy group, an acyl group, a carboxylic acid ester group, an aryloxy group , represents a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, or a phosphonic acid group, and Q ₁ and Q ₂ are never hydrogen atoms at the same time.
Q ₃ represents a hydrogen atom, an alkyl group, an aryl group, or a carboxylic acid ester group.
Furthermore, in formulas (IX) and (X), A1 represents a group represented by -Ar1-X1-(Y1)n1 in formula (I). Therefore, Ar1, X1, Y1 and n1 have the same meanings as those in formula (I).

For example, when producing modified graphene represented by the following formula (XIII), the modified graphene of the following formula (XII) included in formula (I) is produced in advance, and this is used as an intermediate in a further chemical reaction to produce the formula It is okay to lead to (XIII). In this case, a condensation reaction between the carboxylic acid group in formula (XII) and the corresponding amine compound may be used.
Gr1-Ar1-COOH (XII)
Gr1-Ar1-CO-NH-CH ₂ -CH ₂ -CH ₂ -CH ₃ (XIII)

<Reaction mechanism>
The reaction mechanism for obtaining modified graphene according to this embodiment will be described below. It can be assumed that the reaction according to this embodiment also proceeds as an oxidative radical addition reaction, as illustrated in FIG. Note that the reaction mechanism shown in FIG. 2 is an example in which a compound represented by the above formula (IX) is used as a treatment agent.

First, when external energy such as heat or light is applied from the outside to the treatment agent (1), which is stable at room temperature, the substituents P ₁ , P ₂ and P ₃ on the N atom are eliminated, forming a diazene compound (2 ) is thought to be generated. Furthermore, the diazene compound (2) becomes a radical intermediate (3) by oxidation (hydrogen elimination), and the corresponding radical species (4) is generated along with nitrogen elimination from the radical intermediate (3). Then, the radical species (4) undergoes an addition reaction with the double bond of graphene via the intermediate (5), and modified graphene (6) according to the present disclosure is obtained.

<Reaction and purification>
The processing agent used in the production method according to this embodiment is stable at room temperature, and therefore the reaction can be easily controlled by external energy. In the production method according to this embodiment, modified graphene can be produced with high reaction efficiency in a one-pot reaction with graphene without selecting a reaction device or a liquid medium. High reaction efficiency means that surface modification of graphene can be achieved with a smaller amount of treatment agent. Therefore, if the reaction efficiency is high, there is not only a cost advantage, but also the generation of impurities due to the reaction can be reduced, and if there are fewer impurities, the purification efficiency can be improved and the purification time can be shortened. It is also possible to do so.

In the technique disclosed in Patent Document 3, the surface of graphene is modified using a diazonium salt as a treatment agent. Diazonium salts used as processing agents decompose at room temperature with various side reactions. Since reaction control is difficult, when attempting to increase the amount of substituents introduced using a diazonium salt, it is necessary to use the diazonium salt in excess of graphene. However, if the amount of diazonium salt used is suddenly increased, many nitrogen gas bubbles are generated, which has the opposite effect of making it difficult to increase the reaction efficiency.

The processing agent used in the production method according to this embodiment has two nitrogen atoms (NN) in its molecular structure, and has a structure in which A1, which is a functional group that binds to graphene, is bound to the nitrogen atom (N). It is a compound with This treatment agent is thought to have the function of bonding a substituent containing a hydrophilic group or a hydrophobic group to graphene through an oxidative radical addition reaction.

As described above, the treatment agent is chemically stable and is not easily affected by pH and temperature, so the pH and temperature of the reaction system can be set arbitrarily. Specifically, the pH of the reaction system is preferably 1 to 13, more preferably 1 to 10, and particularly preferably 1.5 to 7. In order to increase reaction efficiency, it is preferable that the pH of the reaction system is acidic to neutral. In a high pH range such as alkalinity, the processing agent may decompose. On the other hand, if the pH of the reaction system is less than 1.5, the solubility of the processing agent will be significantly poor, so the reaction time may become longer, and it will be necessary to use a large amount of acidic compounds, making it difficult to perform treatments such as purification. It can be difficult.

Further, in order to control the reaction rate of the radical addition reaction, the temperature may be set at a temperature other than room temperature (25° C.). The temperature may be appropriately set depending on the type of processing agent. Specifically, the temperature is preferably 5 to 80°C, more preferably 10 to 70°C. Increasing the temperature increases the reaction rate, but side reactions tend to occur and the reaction efficiency tends to decrease. On the other hand, when the temperature is lowered, side reactions are less likely to occur, but the reaction rate tends to decrease and the reaction time tends to increase.

The manufacturing method according to this embodiment is usually performed in a liquid medium. The content (mass%) of graphene in the liquid medium is preferably 1.0% by mass or more and 50.0% by mass or less, and 5.0% by mass or more and 40.0% by mass, based on the total mass of the liquid medium. % or less is more preferable. If the content of graphene is too high, the viscosity of the reaction system will increase, making stirring difficult, which may cause a slight decrease in reaction efficiency. On the other hand, if the graphene content is too low, the frequency of contact between the processing agent and graphene within the reaction system may decrease, and the reaction efficiency may decrease somewhat.

<Treatment agent>
As the processing agent used in the production method according to this aspect, for example, at least one kind selected from the group consisting of the compound represented by the above formula (IX) and the compound represented by the following formula (X) is used.
Specific structures of the processing agent represented by the formula (IX) are shown in S1-1 to S1-93. In addition, regarding A1, the same applies to the specific example of formula (I) above.

Examples of formula (IX) in which one or two of P ₁ , P ₂ , and P ₃ are methyl groups, and the total number of carbon atoms in P ₁ , P ₂ , and P ₃ is 2 or less, Examples include S1-1, S1-2, and S1-3.

In formula (IX), examples in which at least one of P ₁ , P ₂ and P ₃ is a t-butoxycarbonyl group include S1-13, S1-14 and S1-15.

In formula (IX), at least one of P ₁ , P ₂ and P ₃ is -S(=O) ₂ -R', and R' is a methyl group, 2-hydroxyethyl group, phenyl Examples of groups or tolyl groups include S1-23, S1-31, S1-37, and S1-40.

Specific structures of the processing agent represented by the formula (X) are shown in S2-1 to S2-40. In addition, regarding A1, the same applies to the specific example of formula (I) above.

The uses of the modified graphene according to the present disclosure produced by the method described above will be described below.
(resin composite)
The resin blended with modified graphene according to the present disclosure (hereinafter referred to as a modified graphene resin composite) is a resin composite that is endowed with the electrical conductivity or thermal conductivity that graphene inherently has, so various product forms can be considered. It will be done. For example, conductive or thermally conductive masterbatches, conductive or thermally conductive sheets, conductive or thermally conductive molded parts such as conductive or thermally conductive trays or conductive or thermally conductive gaskets, or electrode members. Can be mentioned. In addition, it has recently been known that blending graphene has the ability to increase strength and sliding properties, and its application to strength members and slidable members is also possible.

The modified graphene according to the present disclosure can be used by being mixed with various resins, and the type of resin is not particularly limited. The reason for this is that combinations of fillers and resins are generally limited because of compatibility problems and associated problems of poor dispersion (agglomeration). However, in the modified graphene according to the present disclosure, since the substituents to be introduced can be designed taking into consideration compatibility with the resin, the resin is not limited. Specific examples of usable resins include the following. Examples include polyethylene, polystyrene, vinyl acetate resin, vinyl chloride resin, acrylic resin, polyacrylonitrile, polyamide, cellulose acetate resin, cellulose nitrate resin, phenol resin, epoxy resin, silicone resin, natural rubber, and the like.

When manufacturing a modified graphene resin composite according to the present disclosure and manufacturing a conductive sheet or a thermally conductive sheet (modified graphene sheet) using the composite, a silicone resin can be suitably used. Silicone resin can be coated into a film and cured, and the effect of modified graphene can impart thermal conductivity to the surface layer of the product. Furthermore, it can also be used as a conductive sheet or a thermally conductive sheet that has adhesive properties to various adherends. It also has excellent weather resistance and heat resistance.

Specific examples of silicone resins include common silicone resins such as methyl silicone resin, methylphenyl silicone resin, and phenyl silicone resin. Other examples include organic resin-modified silicone resins such as alkyd-modified silicone resins, polyester-modified silicone resins, epoxy-modified silicone resins, urethane-modified silicone resins, and acrylic-modified silicone resins.

Furthermore, a two-component type silicone resin (reactive silicone resin) can also be used. Specific examples of the reactive silicone resin include addition-type cured silicone resins, condensation-type cured silicone resins, peroxide-cured silicone resins, and cationic UV silicone resins. Among these, addition type curing silicone resins, which are easily available and cure even at room temperature, are preferably used. The two compounds used to make addition-cured silicone resins are vinylsiloxanes and hydrosiloxanes that have double bonds. All of them can be obtained and used as commercially available products, and examples of the vinyl-terminated polysiloxane include DMS-V31 (Azumax Co., Ltd.) and DMS-V41 (Azumax Co., Ltd.). Examples of the hydrogen-terminated polysiloxane include DMS-H03 (Azumax Co., Ltd.), HMS-301 (Azumax Co., Ltd.), and HMS-992 (Azumax Co., Ltd.).

The weight average molecular weight (Mw) of the resin used in the present disclosure is preferably 50,000 or less. Generally, when the amount of filler is increased, the viscosity of the resin composite increases, and it is necessary to set the kneading temperature higher. When the weight average molecular weight (Mw) exceeds 50,000, when the modified graphene according to the present disclosure is blended, the viscosity becomes too high to form a sheet, and the kneading temperature increases, making temperature control difficult. etc. may occur.

(dispersion)
The modified graphene according to the present disclosure can be used as a modified graphene dispersion for various purposes. The modified graphene dispersion can be obtained by dispersing modified graphene represented by formula (I) in a dispersion medium.
Examples of distributed processing methods include the following methods. The modified graphene represented by formula (I) and, if necessary, a resin are dissolved in a dispersion medium, and the mixture is thoroughly blended into the dispersion medium while stirring. Furthermore, by applying mechanical shearing force using a dispersing machine such as a ball mill, paint shaker, dissolver, attritor, sand mill, or high-speed mill, the modified graphene represented by formula (I) is stably and finely dispersed into uniform fine particles. can do.

In the present disclosure, the amount of modified graphene in the modified graphene dispersion is preferably 1 to 50 parts by weight based on 100 parts by weight of the dispersion medium. More preferably 2 to 30 parts by weight, particularly preferably 3 to 15 parts by weight. By controlling the content of modified graphene within the above range, an increase in viscosity and a decrease in dispersibility can be suppressed.
The modified graphene dispersion can be dispersed in water either by using modified graphene alone or by using an emulsifier. Examples of the emulsifier include cationic surfactants, anionic surfactants, and nonionic surfactants.

Examples of cationic surfactants include the following.
Dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, etc.
Examples of anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzene sulfate, and sodium lauryl sulfate.
Examples of nonionic surfactants include the following. Dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, monodecanoyl sucrose, etc.

Examples of the organic solvent used as a dispersion medium include the following.
Methyl alcohol, ethyl alcohol, denatured ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, sec-butyl alcohol, tert-amyl alcohol, 3-pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, etc. alcohols; glycols such as methyl cellosolve, ethyl cellosolve, diethylene glycol, diethylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone (2-butanone), methyl isobutyl ketone; ethyl acetate, butyl acetate, ethyl propionate, cellosolve acetate, etc. esters; hydrocarbon solvents such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, xylene; halogenated hydrocarbon solvents such as carbon tetrachloride, trichloroethylene, tetrabromoethane; diethyl ether, dimethyl glycol, trioxane , ethers such as tetrahydrofuran; acetals such as methylal and diethyl acetal; organic acids such as formic acid, acetic acid, and propionic acid; sulfur- and nitrogen-containing organics such as nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethylsulfoxide, and dimethylformamide Compounds.
Further, by using the modified graphene dispersion described above, conductive inks and paints can also be produced.

Hereinafter, the present disclosure will be explained in more detail by giving Examples and Comparative Examples, but the present disclosure is not limited by the following Examples unless it exceeds the gist thereof. Note that "parts" and "%" regarding component amounts are based on mass unless otherwise specified.

(material)
Examples 1-1 to 1-28 relate to the production of modified graphene. The main materials used, ie, graphene, processing agent, and oxidizing agent, are shown in Table 1 below.
The processing agent is a compound represented by the following formula (VI), and the structural formula of A1 is the same as the structure described above (specific example of modified graphene). All of the processing agents were purchased from Sumika Techno Service Co., Ltd.
NH ₂ -NH-A1 (VI)

Further, the names and chemical formulas of the oxidizing agents are as follows.
Phthalocyanine iron (III) chloride (FePc・Cl), potassium ferrocyanide (K ₄ [Fe(CN) ₆ ]・3H ₂ O), iodine (I ₂ ), iron (III) chloride (FeCl ₃ ), sodium periodate (NaIO ₄ ), manganese dioxide (MnO ₂ ), potassium permanganate (KMnO ₄ ), and 35% aqueous hydrogen peroxide solution (H ₂ O ₂ ). All of the oxidizing agents were manufactured by Tokyo Chemical Industry Co., Ltd.

(Production method)
(Manufacturing method 1-A)
The following materials were placed in a 400 mL vessel (manufactured by Imex) and mixed.
・Graphene (product name: xGnP-M5, New Metals End Chemicals Corporation): 18.0g
・Ion exchange water: 162mL
・DMF (N,N-dimethylformamide): 18mL
・Treatment agent (Sumika Techno Service Co., Ltd.): 1.0 mmol/g
・Oxidizing agent (Tokyo Kasei Kogyo Co., Ltd.): 0.1 mmol/g

An 8 mol/L aqueous potassium hydroxide solution was added to adjust the pH of the liquid to 3, and the mixture was stirred at a temperature of 25° C. and a rotation speed of 2,000 rpm for 12 hours. Thereafter, an 8 mol/L aqueous potassium hydroxide solution was added to adjust the pH of the liquid to 10 to obtain a dispersion. The obtained dispersion was centrifuged at a rotational speed of 5,000 rpm for 10 minutes to remove the supernatant and coarse particles, and the supernatant was purified to have an electrical conductivity of 10 μS/cm or less to obtain a modified graphene dispersion. Obtained. Next, the modified graphene dispersion was dried using a freeze-drying method.

(Manufacturing method 1-B)
The following materials were placed in a 400 mL vessel (manufactured by Imex) and mixed.
・Graphene (product name: xGnP-M5, New Metals End Chemicals Corporation): 18.0g
・DMF (N,N-dimethylformamide): 180mL
・Treatment agent (Sumika Techno Service Co., Ltd.): 1.0 mmol/g
・Oxidizing agent (Tokyo Kasei Kogyo Co., Ltd.): 0.1 mmol/g
The resulting dispersion was filtered through a filter paper lined with filter paper, and the filtered solid was washed once with DMF and once with chloroform, and acetone was added to obtain a modified graphene dispersion. Next, the solvent was removed from the modified graphene using an evaporator, and it was dried using a vacuum dryer (50° C.).

(Identification method of modified graphene)
The identification of the produced modified graphene, that is, the quantification of the substituents (hereinafter also referred to as the amount of modification) will be described below. The amount of modification was calculated using the composition of each element in unmodified graphene (raw material) or modified graphene, and the composition ratio obtained using Quantera SXM (manufactured by ULVAC-PHI Co., Ltd.) for X-ray photoelectron measurement and the calculation formula below. Calculated using 1. Note that the excitation X-ray is a monochromatic Al Kα1,2 ray (1486.6 eV), the X-ray diameter is 100 μm, and the photoelectron escape angle is 45°.

To give an example, the elemental composition of the modified graphene in which the structure of A1 is A1-22 was the value shown in the lower part of Table 2 below. On the other hand, the elemental composition of graphene (xGnP-M5 (New Metals End Chemicals Corporation)) used as a raw material was as shown in the upper row of Table 2 below. In this case, the amount of modification of A1-22 with respect to 1 g of modified graphene was estimated to be 0.219 mmol/g from calculation formula 1.

(Evaluation of defect concentration by Raman spectroscopy of modified graphene)
Raman spectroscopic analysis was performed using the following equipment and conditions.
Measuring device: Raman microscope (JASCO NRS-4100)
Measurement conditions: 532 nm laser used, laser intensity 0.3 mW, objective lens 20 times, exposure time 60 seconds, integration 2 times (resolution = 7 cm ^-1 )
When a graphene structure exists, a G band (around 1590 cm ^-1 ) derived from the graphite structure (sp ² bond) and a D band (around 1350 cm ^-1 ) derived from defects are observed. The higher and sharper the intensity of the G band and the lower the intensity of the D band, the fewer defects the graphene has. The defect concentration was evaluated using the following formula.
G/D ratio=g/d
g: G band intensity d: D band intensity

[Evaluation criteria]
A rank...0.95≦g/d
B rank...0.80≦g/d<0.95
C rank...g/d<0.80

(Example 1-1 to Example 1-9, Example 1-17, Example 1-18, Example 1-22)
Modified graphene 1-1 to 1-9, modified graphene 1-17, modified graphene 1-18, and modified graphene 1 were produced according to production method 1-A using the graphene, processing agent, and oxidizing agent listed in Table 1. -22 was manufactured. Next, the elemental composition of the modified graphene was determined by X-ray photoelectron measurement, and the amount of modification was estimated from Formula 1 and is listed in Table 3. Furthermore, the g/d of the produced modified graphene was determined by Raman spectroscopy, evaluated based on evaluation criteria, and is listed in Table 3.

(Example 1-10 to Example 1-16, Example 1-19 to Example 1-21, Example 1-23 to Example 1-28)
Modified graphene 1-10 to 1-16, modified graphene 1-19 to 1-21, and modified graphene 1-23 were produced according to production method 1-B using the graphene, processing agent, and oxidizing agent listed in Table 1. ~1-28 was manufactured. Next, the elemental composition of the modified graphene was determined by X-ray photoelectron measurement, and the amount of modification was estimated from Formula 1 and is listed in Table 3. Furthermore, the g/d of the produced modified graphene was determined by Raman spectroscopy, evaluated based on evaluation criteria, and is listed in Table 3.

(Comparative example 1-1)
Graphene oxide (trade name: GO, New Metals End Chemicals Corporation) was used as comparative compound 1-1. The g/d of the produced graphene oxide was determined by Raman spectroscopy, evaluated based on the evaluation criteria, and is listed in Table 3.

(Comparative example 1-2)
Comparative compound 1-2 was modified graphene obtained by the following production method described in Patent Document 3 using 4-aminobenzoic acid as a treatment agent.
The following materials were placed in a 400 mL vessel (manufactured by Imex) and mixed.
・Graphene (product name: xGnP-M5, New Metals End Chemicals Corporation): 18.0g
・Ion exchange water: 162mL
・4-Aminobenzoic acid (Tokyo Kasei Kogyo Co., Ltd.): 1.0 mmol/g
・Sodium nitrite (Tokyo Kasei Kogyo Co., Ltd.): 1.0 mmol/g

The mixture was stirred for 12 hours at a temperature of 25° C. and a rotation speed of 2,000 rpm. Thereafter, an 8 mol/L aqueous potassium hydroxide solution was added to adjust the pH of the liquid to 10 to obtain a dispersion. The obtained dispersion was centrifuged at a rotational speed of 5,000 rpm for 10 minutes to remove the supernatant and coarse particles, and the supernatant was purified to have an electrical conductivity of 10 μS/cm or less to obtain a modified graphene dispersion. Obtained. Next, the modified graphene dispersion was dried using a freeze-drying method.
The elemental composition of the modified graphene was determined by X-ray photoelectron measurement, and the amount of modification was estimated from Formula 1 and is listed in Table 3. Furthermore, the g/d of the produced modified graphene was determined by Raman spectroscopy, evaluated based on evaluation criteria, and is listed in Table 3.

(Method for producing resin composite of modified graphene)
A resin sheet blended with the modified graphene produced above was produced using any of the following production methods 1-1, 1-2, or 1-3. Furthermore, the obtained sheet was evaluated for electrical conductivity and thermal conductivity.
In addition, a resin sheet containing graphene oxide (comparative compound 1-1) and a resin sheet containing modified graphene (comparative compound 1-2) produced by the manufacturing method described in Patent Document 3 were prepared, and similar results were obtained. We conducted an evaluation.
The above manufacturing method 1-1, manufacturing method 1-2, or manufacturing method 1-3 will be described below. Manufacturing method 1-1 is a method for a sheet using silicone resin, manufacturing method 1-2 is a method for a sheet using urethane resin, and manufacturing method 1-3 is a method for a sheet using polyimide.

(Preparation method 1-1)
Vinyl-terminated polysiloxane DMS-V31 (weight average molecular weight (Mw): 28,000, Azumax Co., Ltd.) 100 parts, hydrogen-terminated polysiloxane HMS-301 (Azumax Co., Ltd.) 5 parts, and modified graphene (or comparative compound) 60 parts The parts were mixed with a spatula.
Next, the mixture was kneaded for 2 minutes using a rotation/revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. To this, 0.8 part of platinum catalyst was added and kneaded with a spatula, then kneaded for 2 minutes with an autorotation-revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. The obtained mixture was applied onto a metal plate using a bar coater, and left to stand in a constant temperature room at 100° C. for 2 hours to cure, thereby obtaining the following silicone resin sheet.
・Silicone resin sheet・Thickness: 200±10μm
・Amount of modified graphene (or comparative compound): 20 vol%
However, the blending amount was calculated assuming that the density of the modified graphene was 2.2 g/cm ³ and the density of the other materials was 0.97 g/cm ³ .

(Preparation method 1-2)
The following materials were mixed and stirred for 1 hour while applying ultrasound to prepare a dispersion.
- 100 parts of polyurethane UR4800 (weight average molecular weight (Mw): 4800, Toyobo Co., Ltd.) as a binder resin - 43 parts of modified graphene (or comparative compound) - Arbitrary amount of THF (tetrahydrofuran, manufactured by Kishida Chemical Co., Ltd.)
The resulting mixture was applied onto a metal plate using a barcoder and dried in a constant temperature dryer at 40°C. Next, the dried body was peeled off from the metal plate, and heated and pressed at 150° C. and 0.5 kgf/m ² for 3 minutes using a small heat press machine (manufactured by As One Co., Ltd.) to obtain the following urethane resin sheet.
・Urethane resin sheet・Thickness: 200±10μm
・Amount of modified graphene (or comparative compound): 20 vol%
However, the blending amount was calculated assuming that the density of the modified graphene was 2.2 g/cm ³ and the density of the urethane resin was 1.28 g/cm ³ .

(Preparation method 1-3)
100 parts of polyimide precursor U-varnish-S (solid content: 20%, N-methylpyrrolidone content: 80%, Ube Industries, Ltd.) and 5.2 parts of modified graphene (or comparative compound) were mixed with a spatula. mixed with.
Next, the mixture was kneaded for 2 minutes using a rotation/revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. The obtained mixture was applied onto a metal plate using a bar coater, left to stand for 2 hours in a thermostatic chamber at 100°C to remove the solvent, and then dried in a vacuum dryer at 100°C under a reduced pressure of 0.05 MPa. It was dried with. Further, it was fired in a muffle furnace at 290°C for 30 minutes and then at 350°C for 30 minutes to obtain the following polyimide sheet.
・Polyimide sheet・Thickness: 85±3μm
...Amount of modified graphene (or comparative compound): 15 vol%
The blending amount was calculated based on the density of modified graphene being 2.2 g/cm ³ and the density of polyimide being 1.47 g/cm ³ .

(Example 1-29 to Example 1-56)
Using modified graphenes 1-1 to 1-28 listed in Table 3, modified graphene-containing silicone resin sheets were produced using the above production method 1-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(Example 1-57, Example 1-58)
Using modified graphene 1-2 and modified graphene 1-8 listed in Table 3, a modified graphene-containing urethane resin sheet was produced using the above production method 1-2. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(Example 1-59)
DMS-V41 (weight average molecular weight (Mw): 50,000, Azumax Co., Ltd.) was used instead of vinyl-terminated polysiloxane DMS-V31, modified graphene 1-2 was used, and the above production method 1-1 was used. Using this method, a modified graphene-containing silicone resin sheet was prepared. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(Example 1-60)
DMS-V46 (weight average molecular weight (Mw): 117,000, Azumax Co., Ltd.) was used instead of vinyl-terminated polysiloxane DMS-V31, modified graphene 1-2 was used, and the above production method 1-1 was used. Using this method, a modified graphene-containing silicone resin sheet was prepared. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(Comparative example 1-3)
A graphene oxide-containing silicone resin sheet was produced using graphene oxide (trade name: GO, New Metals End Chemicals Corporation) and in accordance with the above production method 1-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(Comparative example 1-4)
A graphene oxide-containing silicone resin sheet was produced using modified graphene (comparative compound 1-2) produced using the production method described in Patent Document 3 and using the above production method 1-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 4.

(evaluation)
The electrical conductivity and thermal conductivity of the resin sheet produced above was evaluated by the following method and evaluated according to the following evaluation criteria.

(Conductivity evaluation)
The conductivity was evaluated by the surface electrical resistivity (kΩ/□) of the resin sheet sample. The surface electrical resistivity was measured in accordance with JIS K 7194 "Method for testing the resistivity of conductive plastics using the four-probe method," and the measured values were used to classify the samples into ranks A to C as shown below. Generally, the surface electrical resistivity of a conductive member is less than 1×10 ⁵ Ω/□, and if it is higher than that, it is a static electricity dissipative material (1×10 ⁵ Ω/□ or more to less than 1×10 ⁹ Ω/□) or It is known to be an antistatic member (1×10 ⁹ Ω/□ or more to less than 1×10 ¹² Ω/□). For this reason, in the present disclosure, only resin sheet samples of A rank, which is an acceptable rank as a conductive member, are assigned an acceptable rank.

[Evaluation criteria]
A rank... 10kΩ/□≦Surface electrical resistivity<100kΩ/□
B rank... 100kΩ/□≦Surface electrical resistivity<1000kΩ/□
C rank...1000kΩ/□≦Surface electrical resistivity

(Thermal conductivity evaluation)
Thermal conductivity was evaluated by the thermal conductivity in the thickness direction of a resin sheet sample (thickness: 200±10 μm).
First, the produced resin sheet was cut out into a size of length x width = 6 mm x 11 mm. Using this as a resin sheet sample, the thermal diffusivity α in the thickness direction was measured using a temperature wave thermal analysis method (FTC-1, manufactured by ULVAC Riko). The thermal conductivity λ is calculated by multiplying the thermal diffusivity α obtained by the above measurement by the specific heat Cp (weight fraction average) and the density ρ (volume fraction average) from the formula λ = α × Cp × ρ. Calculated. Note that the density was measured using an underwater displacement method, and the specific heat was measured using a differential scanning calorimeter (PYRIS Diamond DSC-7, DSC, manufactured by Perkin Elmer). The specific heat Cp and density ρ required for calculation are as follows.
Using the obtained thermal conductivity values, they were classified into A rank to C rank as follows. Generally, a resin sheet sample with a thickness direction of 1 W/m/K or more is recognized as a high-performance thermally conductive member, so only resin sheet samples of rank A were ranked as acceptable.

[Evaluation criteria]
A rank...1W/m・K≦thermal conductivity B rank...0.5W/m・K≦thermal conductivity<1W/m・K
C rank...Thermal conductivity <0.5W/m・K

[Density and specific heat of each material used in calculation]
・Density ρ of silicone resin: 0.97 g/cm ³
・Density ρ of urethane resin: 1.28 g/cm ³
・Density ρ of modified graphene and comparative compound 1-2: 2.2 g/cm ³
・Graphene oxide density ρ: 2.1 g/cm ³
・Specific heat Cp of silicone resin: 1600J/kgK
・Specific heat Cp of urethane resin: 1900J/kgK
・Specific heat Cp of modified graphene or comparative compound 1-2: 710 J/kgK
・Specific heat Cp of graphene oxide: 700J/kgK

(Example 1-61, Example 1-62)
Using modified graphene 1-3 or graphene 1-17 listed in Table 3, a modified graphene-containing polyimide sheet was produced using the above production method 1-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 5.

(Comparative example 1-5)
Using unmodified graphene, xGnP-M5 (Nu Metals End Chemicals Corporation), an unmodified graphene-containing polyimide sheet was produced using the above production method 1-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 5.

(Comparative example 1-6)
A graphene oxide-containing polyimide sheet was produced using Comparative Compound 1-1 and the above production method 1-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 5.

(Comparative example 1-7)
A polyimide sheet containing Comparative Compound 1-2 was produced using Comparative Compound 1-2 and the above production method 1-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 5.

[Evaluation of thermal conductivity of polyimide sheet]
The thermal conductivity of the polyimide sheet blended with the modified graphene of the present disclosure and the polyimide sheet blended with Comparative Compound 1-1 or Comparative Compound 1-2 is the thermal conductivity in the thickness direction of the sheet sample (thickness 85 ± 3 μm). It was evaluated based on the percentage.
First, the produced resin sheet was cut out into a size of length x width = 6 mm x 11 mm. Using this as a sheet sample, the thermal diffusivity α in the thickness direction was measured using a temperature wave thermal analysis method (FTC-1, manufactured by ULVAC Riko Co., Ltd.). The thermal conductivity λ is calculated by multiplying the thermal diffusivity α obtained by the above measurement by the specific heat Cp (weight fraction average) and the density ρ (volume fraction average) from the formula λ = α × Cp × ρ. Calculated. Note that the density was measured using an underwater displacement method, and the specific heat was measured using a differential scanning calorimeter (PYRIS Diamond DSC-7, DSC, manufactured by Perkin Elmer). The specific heat Cp and density ρ required for calculation are as follows.
Using the obtained thermal conductivity values, they were classified into A rank to C rank as follows. Generally, a sheet sample with a thickness direction of 1 W/m/K or more is recognized as a high-performance thermally conductive member, so only sheet samples with A rank were ranked as acceptable.

[Evaluation rank]
A rank...0.6W/m/K≦thermal conductivity B rank...0.3W/m/K≦thermal conductivity<0.6W/m/K
C rank...Thermal conductivity <0.3W/m・K

[Density and specific heat of each material used in calculation]
・Polyimide density ρ: 1.47g/cm ³
・Density ρ of modified graphene and comparative compound 1-2: 2.2 g/cm ³
・Graphene oxide density ρ: 2.1 g/cm ³
・Specific heat Cp of polyimide resin: 1130J/kgK
・Specific heat Cp of modified graphene or comparative compound 1-2: 710 J/kgK
・Specific heat Cp of graphene oxide: 700J/kgK
The above results are shown in Table 5.

It was confirmed that the polyimide sheet blended with the modified graphene of the present disclosure exhibits higher thermal conductivity than the polyimide sheet of the comparative example. What is even more interesting is that when comparing the modified graphene-containing polyimide sheet with the unmodified graphene-containing polyimide sheet, the modified graphene-containing polyimide sheet showed higher thermal conductivity.
Although the reason is not clear,
In a tensile test (Instron universal testing machine) in accordance with JIS standard K7161, the tensile strength (at 25°C) of the modified graphene-containing polyimide sheet was 260 MPa.
Considering that the tensile strength (25°C) of the unmodified graphene polyimide sheet was 150 MPa,
The carboxylic acid on the surface of modified graphene and the reactive amine in the varnish, which is a precursor of polyimide, combine to improve the adhesion between graphene and resin, or form a graphene network, resulting in high thermal conductivity. may have led to.

(Manufacture of modified graphene dispersion)
A modified graphene dispersion according to the present disclosure and a comparative graphene dispersion were manufactured by the method described below.

(Example 1-63)
100 parts of modified graphene 12 listed in Table 3, 350 parts of toluene, 350 parts of ethyl acetate, 300 parts of 2-butanone, and 750 parts of glass beads (diameter 1 mm) were mixed as a dispersion medium, and an attritor (Nippon Coke Industry Co., Ltd.) was mixed. Co., Ltd.) for 3 hours. Thereafter, it was filtered through a mesh to obtain a modified graphene dispersion according to the present disclosure.

(Example 1-64)
A modified graphene dispersion was obtained in the same manner as in Example 1-63, except that modified graphene 1-12 was changed to modified graphene 1-21.

(Example 1-65)
A modified graphene dispersion was obtained in the same manner as in Example 1-63, except that modified graphene 1-12 was changed to modified graphene 1-23.

(Example 1-66)
A modified graphene dispersion was obtained in the same manner as in Example 1-63, except that modified graphene 1-12 was changed to modified graphene 1-25.

(Comparative example 1-8)
A comparative graphene dispersion was prepared in the same manner as in Example 63, except that modified graphene 1-12 was changed to comparative compound 1-1 (graphene oxide, trade name: GO, New Metals End Chemicals Corporation). Obtained.

(Comparative example 1-9)
Comparative graphene dispersion was carried out in the same manner as in Example 1-63, except that modified graphene 1-12 was changed to modified graphene (comparative compound 1-2) produced according to the production method described in Patent Document 3. I got a body.

(Comparative example 1-10)
The same procedure as in Example 1-63 was carried out, except that modified graphene 1-12 was changed to comparative compound 1-3 (untreated graphene, trade name: xGnP-M5, New Metals End Chemicals Corporation). A comparative graphene dispersion was obtained.

(evaluation)
(Sample preparation)
Samples were prepared by applying the modified graphene dispersion and the comparative graphene dispersion to a PET film by a bar coating method (bar coater wire number No. 10) and drying under reduced pressure overnight. The surface resistance of the obtained sample was measured by the method described above and evaluated based on the following criteria. The results are shown in Table 6.

[Evaluation criteria]
A rank... 10kΩ/□≦Surface electrical resistivity<100kΩ/□
B rank... 100kΩ/□≦Surface electrical resistivity<1000kΩ/□
C rank...1000kΩ/□≦Surface electrical resistivity

<Production of modified graphene by the method according to the second aspect>
"mmol/g" in the following description regarding the production method shall mean the number of millimoles per 1.0 g of modified graphene.

[Example 2-1]
The modified graphene represented by the formula A1-22 was synthesized as follows.
The following materials were placed in a 400 mL vessel (manufactured by Imex) and mixed.
・Graphene (product name: xGnP-M5, manufactured by New Metals End Chemicals Corporation): 18.0g
・Ion exchange water: 162mL
・DMF (N,N-dimethylformamide): 18mL
・Treatment agent S1-2 (manufactured by Sumika Techno Service Co., Ltd.): 1.0 mmol/g

An 8 mol/L aqueous potassium hydroxide solution was added to adjust the pH of the liquid to 3, and the mixture was stirred at a temperature of 25° C. and a rotation speed of 2,000 rpm for 12 hours. Thereafter, an 8 mol/L aqueous potassium hydroxide solution was added to adjust the pH of the liquid to 10 to obtain a dispersion. The obtained dispersion was centrifuged at a rotation speed of 5,000 rpm for 10 minutes to remove the supernatant and coarse particles, and the supernatant was purified so that the electrical conductivity was 10 μS/cm or less, and the result was expressed by formula A1-22. Modified graphene 2-1 having the structure shown was obtained.
Modified graphene 2-1 was dried by a freeze-drying method, the resulting powder was subjected to X-ray photoelectron spectroscopy, and the amount of modification was estimated according to Formula 1.
Modification amount of modified graphene: 0.125 mmol/g
Elemental composition of graphene used as a raw material (unmodified graphene): Value shown in the upper row of Table 7 Elemental composition of modified graphene: Value shown in the lower row of Table 7

[Examples 2-2 to 2-48]
Modified graphenes 2-2 to 2-48 were obtained in the same manner as in Example 1, except that the treatment agent was changed to the treatment agent shown in Table 8A (all manufactured by Sumika Techno Service Co., Ltd.).
The structures and amounts of modification of the obtained modified graphenes 2-2 to 2-48 are shown in Table 8A.

[Comparative example 2-1]
Graphene oxide (trade name: GO, manufactured by New Metals End Chemicals Corporation) was used as Comparative Compound 2-1.
[Comparative example 2-2]
Comparative compound 2-2 was modified graphene obtained by the method described in Patent Document 3 using 4-aminobenzoic acid as a treatment agent.

[Evaluation of defect concentration of modified graphene]
Raman spectroscopic analysis was performed using the following equipment and conditions.
Measuring device: Raman microscope (JASCO NRS-4100)
Measurement conditions: 532 nm laser used, laser intensity 0.3 mW, objective lens 20 times, exposure time 60 seconds, integration 2 times (resolution = 7 cm ^-1 )
When a graphene structure exists, a G band (around 1590 cm ^-1 ) derived from the graphite structure (sp ² bond) and a D band (around 1350 cm ^-1 ) derived from defects are observed. The higher and sharper the intensity of the G band and the lower the intensity of the D band, the fewer defects the graphene has. The defect concentration was evaluated using the following formula.
G/D ratio=g/d
g: G band intensity d: D band intensity

The evaluation criteria are as follows.
A rank: 0.95≦g/d
B rank: 0.80≦g/d<0.95
C rank: g/d<0.80
The above results are shown in Tables 8A and 8B.

(Method for producing resin composite of modified graphene)
A resin sheet containing the modified graphene produced above was produced using any of the following production methods 2-1, 2-2, or 2-3. Furthermore, the obtained sheet was evaluated for electrical conductivity and thermal conductivity.
In addition, a resin sheet containing graphene oxide (comparative compound 2-1) and a resin sheet containing modified graphene (comparative compound 2-2) produced by the manufacturing method described in Patent Document 3 were prepared, and similar We conducted an evaluation.
Manufacturing method 2-1, manufacturing method 2-2, or manufacturing method 2-3 will be described below. Manufacturing method 2-1 is a method for a sheet using silicone resin, manufacturing method 2-2 is a method for a sheet using urethane resin, and manufacturing method 2-3 is a method for a sheet using polyimide.

[Production method 2-1]
Vinyl-terminated polysiloxane DMS-V31 (molecular weight (Mw): 28,000, Azumax Co., Ltd.) 100 parts, hydrogen-terminated polysiloxane HMS-301 (Azumax Co., Ltd.) 5 parts, and modified graphene (or comparative compound) 60 parts The parts were mixed with a spatula.
Next, the mixture was kneaded for 2 minutes using a rotation/revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. To this, 0.8 part of platinum catalyst was added and kneaded with a spatula, then kneaded for 2 minutes with an autorotation-revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. The obtained mixture was applied onto a metal plate using a bar coater, and left to stand in a constant temperature room at 100° C. for 2 hours to cure, thereby obtaining the following silicone resin sheet.
・Silicone resin sheet・Thickness: 200±10μm
...Amount of modified graphene (or comparative compound): 20 vol%
The blending amount was calculated based on the density of modified graphene being 2.2 g/cm ³ and the density of other materials being 0.97 g/cm ³ .

[Production method 2-2]
As a binder resin, 100 parts of polyurethane UR4800 (molecular weight (Mw): 4800, manufactured by Toyobo Co., Ltd.), 43 parts of modified graphene (or comparative compound), and an arbitrary amount of THF (tetrahydrofuran, manufactured by Kishida Chemical Co., Ltd.) were mixed. A dispersion was prepared by stirring for 1 hour while applying ultrasound.
The resulting mixture was applied onto a metal plate using a barcoder and dried in a constant temperature dryer at 40°C. Next, the dried body was peeled off from the metal plate, and heated and pressed at 150° C. and 0.5 kgf/m ² for 3 minutes using a small heat press machine (manufactured by As One Co., Ltd.) to obtain the following urethane resin sheet.
・Urethane resin sheet・Thickness: 200±10μm
・Amount of modified graphene (or comparative compound): 20 vol%
The blending amount was calculated based on the density of the modified graphene being 2.2 g/cm ³ and the density of the urethane resin being 1.28 g/cm ³ .

[Production method 2-3]
100 parts of polyimide precursor U-varnish-S (solid content: 20%, N-methylpyrrolidone content: 80%, Ube Industries, Ltd.) and 5.2 parts of modified graphene (or comparative compound). Mixed with a spatula.
Next, the mixture was kneaded for 2 minutes using a rotation/revolution mixer (NR-50, manufactured by Shinky Co., Ltd.), and defoamed for 1 minute. The obtained mixture was applied onto a metal plate using a bar coater, left to stand for 2 hours in a thermostatic chamber at 100°C to remove the solvent, and then dried in a vacuum dryer at 100°C under a reduced pressure of 0.05 MPa. It was dried with. Further, it was fired in a muffle furnace at 290°C for 30 minutes and then at 350°C for 30 minutes to obtain the following polyimide sheet.
・Polyimide sheet・Thickness: 85±3μm
...Amount of modified graphene (or comparative compound): 15 ol%
The blending amount was calculated based on the density of modified graphene being 2.2 g/cm ³ and the density of polyimide being 1.47 g/cm ³ .

[Examples 2-49 to 2-94]
Modified graphene-containing silicone resin sheets were produced using the modified graphenes 2-1 to 2-46 listed in Table 8 and the above production method 2-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Example 2-95, Example 2-96]
Using modified graphene 2-47 and modified graphene 2-48 listed in Table 8, a modified graphene-containing urethane resin sheet was produced using the above production method 2-2. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Example 2-97]
DMS-V41 (molecular weight (Mw): 50,000, Azumax Co., Ltd.) was used instead of vinyl-terminated polysiloxane DMS-V31, modified graphene 2-1 was used, and the above production method 2-1 was used. A modified graphene-containing silicone resin sheet was prepared. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Example 2-98]
DMS-XX46 (molecular weight (Mw): 117,000, Azumax Co., Ltd.) was used instead of vinyl-terminated polysiloxane DMS-XX31, modified graphene 2-2 was used, and the above production method 2-1 was used. A modified graphene-containing silicone resin sheet was prepared. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Example 2-99, Example 2-100]
Using modified graphene 2-24 or graphene 2-25 listed in Table 8, a modified graphene-containing polyimide sheet was produced using the above production method 2-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 10.

[Comparative example]
Compounds for comparison are shown below.
Comparative compound 2-1: Graphene oxide (product name: GO, manufactured by New Metals End Chemicals Corporation)
Comparative compound 2-2: graphene obtained according to the manufacturing method described in Patent Document 3

[Comparative example 2-4]
A graphene oxide-containing silicone resin sheet was produced using Comparative Compound 2-1 and the above production method 2-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Comparative example 2-5]
A silicone resin sheet containing Comparative Compound 2-2 was produced using Comparative Compound 2-2 and the above Production Method 2-1. Further, the sheet was cut into a predetermined sample shape, and conductivity evaluation and thermal conductivity evaluation were performed, and the results are listed in Table 9.

[Comparative example 2-6]
A graphene oxide-containing silicone resin sheet was produced using Comparative Compound 2-1 and the above production method 2-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 10.

[Comparative example 2-7]
A silicone resin sheet containing Comparative Compound 2-2 was produced using Comparative Compound 2-2 and the above Production Method 2-3. Furthermore, the sheet was cut into a predetermined sample shape and thermal conductivity evaluation was performed, and the results are listed in Table 10.

(evaluation)
[Conductivity evaluation]
The conductivity was evaluated by the surface electrical resistivity (kΩ/□) of the silicone resin sheet samples or urethane resin sheets obtained in Examples and Comparative Examples. The surface electrical resistance value was measured in accordance with JIS K 7194 "Method for testing the resistivity of conductive plastics using the four-probe method," and the measured values were used to classify the samples into ranks A to C as shown below. In general, the surface resistivity of a conductive member is less than 1×10 ⁵ Ω/□, and if it is higher than that, it is a static electricity dissipative material (1×10 ⁵ Ω/□ or more to less than 1×10 ⁹ Ω/□) or a charged It is known to be a prevention member (1×10 ⁹ Ω/□ or more to less than 1×10 ¹² Ω/□). For this reason, in the present disclosure, only resin sheet samples of A rank, which is an acceptable rank as a conductive member, are assigned an acceptable rank.
[Evaluation rank]
A rank... 10kΩ/□≦Surface electrical resistivity<100kΩ/□
B rank... 100kΩ/□≦Surface electrical resistivity<1000kΩ/□
C rank...1000kΩ/□≦Surface electrical resistivity

[Thermal conductivity evaluation]
Thermal conductivity was determined by the thickness of the silicone resin sheet, urethane resin sheet sample, or polyimide sheet (85 ± 3 μm) obtained in Examples 2-1 to 2-100 and Comparative Examples 2-4 to 2-7. The thermal conductivity in the horizontal direction was evaluated.
First, the produced resin sheet was cut out into a size of length x width = 6 mm x 11 mm. Using this as a resin sheet sample, the thermal diffusivity α in the thickness direction was measured using a temperature wave thermal analysis method (FTC-1, manufactured by ULVAC Riko). The thermal conductivity λ is calculated by multiplying the thermal diffusivity α obtained by the above measurement by the specific heat Cp (weight fraction average) and the density ρ (volume fraction average) from the formula λ = α × Cp × ρ. Calculated. Note that the density was measured using an underwater displacement method, and the specific heat was measured using a differential scanning calorimeter (PYRIS Diamond DSC-7, DSC, manufactured by Perkin Elmer). The specific heat Cp and density ρ required for calculation are as follows.

First, using the thermal conductivity values of the silicone resin sheet and urethane resin sheet samples obtained in Examples 2-1 to 2-98, Comparative Example 2-4, or Comparative Example 2-5, the following Classified into A-rank to C-rank. In general, in the case of general-purpose resins that have been given thermal conductivity, they are recognized as high-performance thermally conductive materials if they have a thermal conductivity of 1 W/m/K or more in the thickness direction, so A-rank resin sheets Only samples were ranked as acceptable.

[Evaluation rank]
A rank...1W/m・K≦thermal conductivity B rank...0.5W/m・K≦thermal conductivity<1W/m・K
C rank...Thermal conductivity <0.5W/m・K

[Density and specific heat of each material used in calculation]
・Density ρ of silicone resin: 0.97 g/cm ³
・Density ρ of urethane resin: 1.28 g/cm ³
・Density ρ of modified graphene and comparative compound 2-2: 2.2 g/cm ³
・Graphene oxide density ρ: 2.1 g/cm ³
・Specific heat Cp of silicone resin: 1600J/kgK
・Specific heat Cp of urethane resin: 1900J/kgK
・Specific heat Cp of modified graphene or comparative compound 2-2: 710 J/kgK
・Specific heat Cp of graphene oxide: 700J/kgK
The above results are shown in Table 9.

Furthermore, using the thermal conductivity values of the polyimide sheets obtained in Example 2-99, Example 2-100, Comparative Example 2-6, or Comparative Example 2-7, rank A to C was determined as follows. Classified. Only sheet samples with rank A were ranked as acceptable. Note that, unlike the above-mentioned general-purpose resin sheets, there are no general thermal conductivity standards for engineering plastic resins.
[Evaluation rank]
A rank...0.6W/m・K≦thermal conductivity B rank...0.3W/m・K≦thermal conductivity<0.6W/m・K
C rank...Thermal conductivity <0.3W/m・K

[Density and specific heat of each material used in calculation]
・Polyimide density ρ: 1.47g/cm ³
・Density ρ of modified graphene and comparative compound 2-2: 2.2 g/cm ³
・Graphene oxide density ρ: 2.1 g/cm ³
・Specific heat Cp of polyimide resin: 1130J/kgK
・Specific heat Cp of modified graphene or comparative compound 2-2: 710 J/kgK
・Specific heat Cp of graphene oxide: 700J/kgK
The above results are shown in Table 10.

<Production of modified graphene dispersion>
A modified graphene dispersion according to the present disclosure and a comparative graphene dispersion were manufactured by the method described below.

[Example 2-201: Production example 2-201 of modified graphene dispersion]
100 parts of modified graphene 2-20, 350 parts of toluene, 350 parts of ethyl acetate, 300 parts of 2-butanone, and 750 parts of glass beads (diameter 1 mm) were mixed as a dispersion medium, and Attritor [manufactured by Nippon Coke Industry Co., Ltd.] was mixed. ] for 3 hours. Thereafter, each was filtered through a mesh to obtain a modified graphene dispersion according to the present disclosure.

[Example 2-202 to 2-208: Production example of modified graphene dispersion 2-202 to 2-208]
A modified graphene dispersion was obtained in the same manner as in Production Example 2-201 of graphene dispersion, except that modified graphene 2-20 was changed to the modified graphene shown in Table 11.

[Comparative Examples 2-201 to 2-203: Manufacturing Examples of Comparative Graphene Dispersion 2-201 to 2-203]
A comparative graphene dispersion was obtained in the same manner as in Graphene Dispersion Production Example 2-201, except that modified graphene 2-20 was changed to Comparative Compounds 2-1 to 2-3 shown in Table 11.

<Evaluation>
<Sample preparation>
Samples were prepared by applying the modified graphene dispersion and the comparative graphene dispersion to a PET film by a bar coating method (bar coater wire number No. 10) and drying under reduced pressure overnight. The obtained sample was evaluated using the above-mentioned conductivity evaluation method.
The above results are shown in Table 11.

Claims (20)

Modified graphene,
It has a structure represented by the following formula (I),
Modified graphene characterized in that the ratio (g/d) between G band intensity g and D band intensity d in a Raman spectroscopic spectrum is 1.0 or more:
Gr1-Ar1-X1-(Y1)n1 (I)
(In the formula (I),
Gr1 is single layer graphene or multilayer graphene,
Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

A group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom of Ar1,
When X1 is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, it is an atom or group bonded to a carbon atom in the alkylene group,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, as well as,
X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, -O-, -NH-,

In the case of a group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene groups, an atom or group bonded to a carbon atom or nitrogen atom in the group And,
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups. ). Claim 1, wherein Ar1 in the formula (I) is a phenylene group, biphenylene group, triphenylene group, or naphthalene group, X1 is a single bond, Y1 is a carboxylic acid group, and n1 is 1 to 6. modified graphene. Ar1 in the formula (I) is a phenylene group, and X1 represents at least one carbon atom in a branched alkylene group having 1 to 20 carbon atoms,

The modified graphene according to claim 1, wherein Y1 is a phosphoric acid group and n1 is 1 to 4. The modified graphene according to claim 1, wherein Ar1 in the formula (I) is a phenylene group, X1 is a single bond, Y1 is a nitro group, and n1 is 1 to 3. Ar1 in the formula (I) is a phenylene group, and X1 represents at least one carbon atom in a branched alkylene group having 1 to 20 carbon atoms,

The modified graphene according to claim 1, wherein the modified graphene is a group substituted with -CO- or -CONH-, Y1 is a hydrogen atom or a vinyl group, and n1 is 1 to 3. The modified graphene according to claim 1, wherein Y1 is a siloxane group, and the siloxane group is at least one selected from the group consisting of the following formulas (II) to (IV):

(In the formulas (II) to (IV), R1 to R23 each independently represent an alkyl group, an amino group, a vinyl group, an acrylic group, a carboxylic acid ester group, a carboxylic acid group, a hydroxy group, or an aryl group, and L1 represents an integer from 1 to 6, and L2 and (L3+L4) are numbers from 0 to 650.) The modified graphene according to any one of claims 1 to 6, wherein when Y1 in the formula (I) is a group, the number of moles of the group per 1 g of modified graphene is 0.10 mmol or more. The modified graphene according to claim 7, wherein when Y1 in the formula (I) is a group, the number of moles of the group per 1 g of modified graphene is 0.10 mmol or more and 1.20 mmol or less. A method for producing modified graphene, the method comprising:
A compound represented by the following formula (V) is subjected to a radical addition reaction by abstracting hydrogen atoms from the compound in a liquid medium in the presence of an oxidizing agent at a temperature of -5°C or higher and 80°C or lower. , a bonding step of bonding a group represented by A1 in the following formula (V) to a carbon atom on the surface of graphene as a raw material ,
A method for producing modified graphene , characterized in that the oxidizing agent has an oxidation potential of +0.50 V or more and +1.70 V or less :
HN=N-A1 (V)
(In the formula (V), A1 is a group represented by -Ar1-X1-(Y1)n1,
Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

-CO-, -COO-, -CONH-, and a group substituted with at least one structure selected from the group consisting of an arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom of Ar1,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, and X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 10 carbon atoms, -O-, -NH-,

-CO-, -COO-, -CONH-, and an atom or group bonded to a carbon atom or nitrogen atom in the group in the case of a group substituted with at least one structure selected from the group consisting of an arylene group. And,
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups. ). In the bonding step, the compound represented by the following formula (VI) is bonded to the compound represented by the formula (VI) in a liquid medium in the presence of the oxidizing agent at -5°C to 80°C. The method for producing modified graphene according to claim 9, comprising the step of producing a compound represented by the formula (V) by abstracting hydrogen atoms from:
H ₂ N-NH-A1 (VI)
(A1 in the formula (VI) is the same as A1 in the formula (V).) The compound represented by the formula (VI) is
A compound in which Ar1 is a phenylene group, X1 is a single bond, and Y1 is a carboxylic acid group; Claim 10, wherein at least one of the compounds is a branched or cyclic alkylene group in which at least one carbon atom is replaced with -NH- or -CO-, and Y1 is a phosphoric acid group. The method for producing modified graphene described in . The oxidizing agent is a halogenated metal compound, a metal porphyrin compound, or a hexacyano metal acid compound of at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Mg, Mn, Cr, and Mo. A method for producing modified graphene according to any one of claims 9 to 11 . A method for producing modified graphene, the method comprising:
At least one treatment agent selected from the group consisting of a compound represented by the following formula (IX) and a compound represented by the following formula (X) is applied at a pH of 1.5 to 7 and a temperature of 5 to 80°C. characterized by having a step of reacting with graphene as a raw material to chemically bond the group represented by A1 in the formula (IX) or the formula (X) to a carbon atom on the surface of the graphene. Method for producing modified graphene:

(In the above formula (IX),
P ₁ , P ₂ , and P ₃ each independently represent a hydrogen atom, an alkyl group, an aryl group, a carboxylic acid ester group, or -S(=O)2-R', and P ₁ , P ₂ , and P All ₃ cannot become hydrogen atoms at the same time.
R' represents a hydroxy group, an alkyl group, or an aryl group.
A1 is a group represented by -Ar1-X1-(Y1)n1.
In the formula (X),
Q1 and Q2 each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a cyano group, a nitro group, an amino group, an alkoxy group, a thioalkoxy group, an acyl group, a carboxylic acid ester group, an aryloxy group, or a carboxylic acid group. group, a sulfonic acid group, a phosphoric acid group, or a phosphonic acid group, and Q1 and Q2 cannot be hydrogen atoms at the same time. Q3 represents a hydrogen atom, an alkyl group, an aryl group, or a carboxylic acid ester group. A1 is a group represented by -Ar1-X1-(Y1)n1.
The Ar1 is an arylene group having 6 to 18 carbon atoms,
X1 is
single bond,
A linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, or
At least one carbon atom in a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms is replaced by -O-, -NH-,

A group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group,
Y1 is
When X1 is a single bond, it is an atom or group bonded to at least one carbon atom in Ar1,
When X1 is a linear, branched or cyclic alkylene group having 1 to 20 carbon atoms, it is an atom or group bonded to a carbon atom in the alkylene group,
X1 replaces one carbon atom in the alkylene group with 1 carbon number with -O-, -NH-, or

In the case of a group substituted with, it is an atom or group bonded to an oxygen atom or a nitrogen atom in the group,
When X1 is a group in which one carbon atom in an alkylene group having 1 carbon number is replaced with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene group, as well as,
X1 represents at least one carbon atom in a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, -O-, -NH-,

In the case of a group substituted with at least one structure selected from the group consisting of -CO-, -COO-, -CONH-, and arylene groups, an atom or group bonded to a carbon atom or nitrogen atom in the group And,
The Y1 is
Hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom,
a fluoroalkyl group having 1 to 6 carbon atoms,
Cyano group, nitro group, acyl group, amide group, vinyl group, carboxylic acid group, carboxylic acid ester group, phosphoric acid group,
an alkylsilyl group having 3 to 6 carbon atoms,
At least one atom or group selected from the group consisting of an alkylsilyl ether group having 3 to 6 carbon atoms, and a siloxane group,
n1 represents an integer of 1 or more, and when n1 is 2 or more, Y1 may be the same group or different groups. ) The modified graphene according to claim 13 , wherein in the formula (IX), one or two of P1, P2, and P3 are methyl groups, and the total number of carbon atoms in P1, P2, and P3 is 2 or less. Production method. The method for producing modified graphene according to claim 13 or 14 , wherein at least one of P1, P2, and P3 in the formula (IX) is a t-butoxycarbonyl group. In the formula (IX), at least one of P1, P2, and P3 is -S(=O)2-R', and R' is a methyl group, a 2-hydroxyethyl group, a phenyl group, or tolyl group, the method for producing modified graphene according to claim 13 or 14 . A modified graphene resin composite comprising at least the modified graphene according to any one of claims 1 to 8 and a resin. The modified graphene resin composite according to claim 17 , wherein the resin has a weight average molecular weight of 50,000 or less. A modified graphene sheet obtained by curing or molding the modified graphene resin composite according to claim 17 or 18 . A modified graphene dispersion comprising the modified graphene according to any one of claims 1 to 8 and water or an organic solvent.

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