JP7749313B2 - Durability improver - Google Patents

Description

The present invention relates to a durability improver.

Plastic materials (resins) are required to have a longer lifespan.

Plastic degradation is often caused by a combination of factors, including light, heat, oxygen, metal ions, acid, and water (see, for example, Non-Patent Documents 1 and 2).

Hiroshi Yamanoi, "Mechanism of Degradation and Discoloration of Polymer Materials and Its Stabilization Techniques," Journal of the Materials Life Society 19.3 (2007): 103-108. Iizuka, Tomonori, Otake, Yoshito, and Tanaka, Keiji. "Effect of Moisture on Photodegradation of Polypropylene." Materials 65.11 (2016): 812-817.

The object of the present invention is to provide a durability improver that is easily dispersed in resin and can improve the durability of the resin.

As a result of extensive research to achieve the above-mentioned objective, the inventors discovered that by incorporating flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, it is possible to obtain a durability improver that is easily dispersed in resin and can improve the durability of the resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). Based on this finding, the inventors conducted further research and completed the present invention. Specifically, the present invention encompasses the following features:

Item 1. A durability improver containing flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group that has high affinity with carbon.

Item 2. The durability improver according to Item 1, wherein the thickness of the flaky carbon is 1 to 100 nm.

Item 3. The hydrophilic group has general formulas (1) to (4):

[In the formula, —OH represents an alcoholic hydroxyl group or a phenolic hydroxyl group. R represents a divalent organic group. ^X1 represents a hydrogen atom, an alkali metal, _NH4 , or an organic ammonium group. ^X2 represents a hydrogen atom, an alkali metal, _NH4 , an organic ammonium group, or an alkyl group. The oxygen atom in general formula (2) is an ether bond.]
Item 3. The durability improver according to Item 1 or 2, wherein the durability improver is at least one represented by the formula:

Item 4. The durability improver according to any one of Items 1 to 3, wherein the hydrophilic group is a phenolic hydroxyl group and/or a polyoxyethylene group.

Item 5. The durability improver according to any one of Items 1 to 4, wherein the hydrophobic group is at least one selected from the group consisting of an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and a polyoxyalkylene group having 3 or more carbon atoms.

Item 6. The durability improver according to any one of Items 1 to 5, wherein the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon is a polyphenol.

Item 7. The durability improver according to any one of Items 1 to 6, containing 1 to 1,000 parts by mass of an organic compound having a hydrophilic group and a hydrophobic group that has high affinity for carbon per 100 parts by mass of the flaky carbon.

Item 8. The durability improver according to any one of items 1 to 7, which is an antioxidant.

Item 9. A method for producing the durability improver according to any one of items 1 to 8, comprising:
(1) A production method comprising a step of removing a solvent from a dispersion containing the flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon, and a solvent.

Item 10. The manufacturing method described in Item 9, wherein the step of removing the solvent is a step of concentrating the dispersion.

Item 11. The manufacturing method described in Item 9 or 10, wherein the solvent is water.

Item 12. A resin durability improving composition containing the durability improver described in any one of items 1 to 8 and a resin.

Item 13. The resin durability composition according to Item 12, wherein the resin is an aromatic polymer compound.

Item 14. A method for producing the resin durability composition according to item 12 or 13,
(2) A manufacturing method comprising a step of kneading the durability improver with a resin.

The present invention makes it possible to obtain a durability improver that is easily dispersed in resin and can improve the durability of the resin.

The structure of the durability improver of the present invention is shown below when the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is low (when the surface of the flaky carbon is coated with an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon). The structure of the durability improver of the present invention is shown when the content of an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon is high (when flaky carbon is dispersed in an organic compound having a hydrophobic group with high affinity for carbon).

In this specification, the term "containing" encompasses the concepts of "comprise," "consist essentially of," and "consist only of." Furthermore, in this specification, when a numerical range is indicated as "A to B," it means A or more and B or less.

1. Durability Improver The durability improver of the present invention contains flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group that has high affinity with carbon.

(1-1) Flaky Carbon Flaky carbon mainly functions as a radical trapping agent, but also functions as an ultraviolet absorber, a heat dissipation material, a gas barrier material, a hydrophobic material, a strength improving agent, and the like.

Thinner flake carbon is preferable because it has better reinforcing properties for durability against resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), and the thickness is preferably 1 to 100 nm, and more preferably 1 to 20 nm. Similarly, the content of flake carbon with a thickness of 1 to 10 nm is preferably 80% or more, and more preferably 90% or more, where the total number of flake carbon is 100%. In other words, thicker flake carbon may be included, but it is preferable that the thickness of the majority of flake carbon is 10 nm or less. The thickness of the flake carbon is measured by observation with a transmission electron microscope (TEM).

Thinner flake carbon is preferable because it has better reinforcing properties in terms of durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). However, flake carbon with a layered structure of 300 or fewer layers of stacked graphene (i.e., 1 to 300 layers) is preferred, with flake carbon with a layered structure of 1 to 60 layers of stacked graphene being more preferred. Similarly, the content of flake carbon with 1 to 30 stacked layers is preferably 80% or more, and more preferably 90% or more, of the total number of flake carbons being 100%. In other words, thicker flake carbons may be included, but the thickness of the majority of the flake carbons is preferably 30 layers or less. The stacking of flake carbons is calculated from the thickness measured by transmission electron microscope (TEM) observation.

Since flake carbon typically has a planar shape with many convex and concave angles, it is difficult to define its dimensions in general terms, other than thickness. In this specification, the size of a piece of flake carbon is defined as the distance between the furthest convex angles on that piece of flake carbon.

The size of such flake carbon is preferably 20 nm or more, more preferably 100 nm or more, and even more preferably 200 nm or more. Using flake carbon of this size makes it easier to further improve the strengthening properties of durability against resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). Note that larger flake carbon sizes are preferable because they provide better strengthening properties of durability against resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), so there is no upper size limit, but it is typically 100 μm. The size of the flake carbon is measured by observation with a transmission electron microscope (TEM).

In the durability improver of the present invention, the content of flaky carbon is not particularly limited. However, from the viewpoint of enhancing durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.) against resins, the content is preferably 10 to 95% by mass, and more preferably 15 to 90% by mass, of the total amount of the durability improver of the present invention taken as 100% by mass. Note that, when thermal conductivity to resins, radical trapping effect, light resistance, etc. are prioritized, a higher content of flaky carbon is preferred, and 50 to 95% by mass, and more preferably 65 to 90% by mass, of the total amount of the durability improver of the present invention taken as 100% by mass. Furthermore, when prioritizing antioxidant effect, dispersibility of flaky carbon, etc., a lower content of flaky carbon is preferred, and 10 to 90% by mass, and more preferably 15 to 75% by mass, of the total amount of the durability improver of the present invention taken as 100% by mass.

(1-2) Organic Compound Having a Hydrophilic Group and a Hydrophobic Group with High Affinity for Carbon In the present invention, by using an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, the flaky carbon that maintains the graphene structure can be maintained in a uniformly dispersed state in the durability improver of the present invention without agglomeration, thereby improving durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). Note that the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon can also function as a dispersant for uniformly dispersing the flaky carbon.

The organic compound having such a hydrophilic group and a hydrophobic group that has a high affinity for carbon is not particularly limited, and a wide variety of organic compounds (especially water-soluble compounds) that can function as a dispersant for flaky carbon can be used.

Of these, the hydrophobic groups contained in organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon are not particularly limited, but alkyl groups, alkenyl groups, cycloalkyl groups, aryl groups, polyoxyalkylene groups with 3 or more carbon atoms, etc. are preferred. Organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon can contain one or more types of such hydrophobic groups. Furthermore, when multiple hydrophobic groups are used, multiple identical hydrophobic groups may be used, or multiple different hydrophobic groups may be used.

The alkyl group may be either a linear or branched alkyl group, but from the viewpoint of affinity with carbon, a linear alkyl group is preferred. Furthermore, from the viewpoint of affinity with carbon, the number of carbon atoms in the alkyl group is preferably 2 or more, more preferably 3 to 22, and even more preferably 4 to 18. Examples of such alkyl groups include n-butyl, n-pentyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n-dodecyl (or n-lauryl), n-tridecyl, n-tetradecyl (or n-myristyl), n-pentadecyl, n-hexadecyl (or n-cetyl), and n-octadecyl.

This alkyl group may or may not have a substituent. Examples of such substituents include a cycloalkyl group, an aryl group, and an aralkyl group. Examples of cycloalkyl groups and aryl groups are described below.

As an aralkyl group as a substituent on an alkyl group, an aralkyl group having 7 to 14 carbon atoms and an aryl group (described below) and an alkyl group having 1 to 6 carbon atoms is preferred, specifically, a benzyl group, a phenethyl group, etc. are preferred.

The substituents are not limited to those mentioned above, and may also have groups derived from the fluorene structure (such as fluorenyl groups). When water solubility is particularly important, phenyl groups and the like are preferred as substituents. When compatibility with flaky carbon and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping properties, etc.) are particularly important, naphthyl groups, fluorenyl groups and the like are preferred as substituents.

From the viewpoint of affinity with carbon and water solubility, the alkenyl group preferably has 2 or more carbon atoms, more preferably 3 to 100, and even more preferably 4 to 30. Examples of such alkenyl groups include butenyl, hexenyl, octenyl, decenyl, dodecenyl, oleyl, and linoleyl groups.

This alkenyl group may or may not have a substituent. Examples of such substituents include alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups. Examples of aralkyl groups include those listed above, and examples of cycloalkyl groups and aryl groups include those listed below.

As the alkyl group as a substituent on the alkenyl group, an alkyl group having 1 to 6 carbon atoms is preferred, and specifically preferred are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups.

The substituents are not limited to those mentioned above, and may also have groups derived from the fluorene structure (such as fluorenyl groups). When water solubility is particularly important, phenyl groups and the like are preferred as substituents. When compatibility with flaky carbon and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping properties, etc.) are particularly important, naphthyl groups, fluorenyl groups and the like are preferred as substituents.

Preferred cycloalkyl groups are those having 5 to 10 carbon atoms (preferably 5 to 8, and particularly 5 to 6), and specific examples include cyclopentyl and cyclohexyl groups.

This cycloalkyl group may or may not have a substituent. Such substituents include alkyl groups, aryl groups, and aralkyl groups.

As the alkyl group as a substituent of the cycloalkyl group, an alkyl group having 1 to 6 carbon atoms is preferred, and specifically preferred are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups.

Aryl groups and aralkyl groups as substituents on cycloalkyl groups include those exemplified above.

The substituents are not limited to those mentioned above, and may also have groups derived from the fluorene structure (such as fluorenyl groups). When water solubility is particularly important, phenyl groups and the like are preferred as substituents. When compatibility with flaky carbon and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping properties, etc.) are particularly important, naphthyl groups, fluorenyl groups and the like are preferred as substituents.

The aryl group is preferably an aryl group having 6 to 22 carbon atoms (particularly 6 to 18 carbon atoms), and can be any of a monocyclic aryl group, a fused ring aryl group, and a polycyclic aryl group. Examples include a phenyl group, a naphthyl group, an anthracenyl group, a tetracenyl group, a phenanthrenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, an acenaphthenyl group, an acenaphthylenyl group, a pyrenyl group, a chrysenyl group, and a triphenylenyl group. From the standpoint of affinity with carbon, aryl groups having two or more aromatic rings (fused ring aryl groups and polycyclic aryl groups) are preferred.

This aryl group may or may not have a substituent. Examples of such substituents include alkyl groups, cycloalkyl groups, and aralkyl groups.

As the alkyl group as a substituent on the aryl group, an alkyl group having 1 to 6 carbon atoms is preferred, and specifically preferred groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

Cycloalkyl groups and aralkyl groups as substituents on aryl groups include those exemplified above.

The substituents are not limited to those listed above, and may also include groups derived from the fluorene structure (such as a fluorenyl group).

Polyoxyethylene groups are typically hydrophilic, but polyoxyalkylene groups with three or more carbon atoms, such as polyoxypropylene and polyoxybutylene groups, become more hydrophobic as the degree of polymerization increases, and they function as hydrophobic groups. Polyoxypropylene groups with a degree of polymerization of four or more and polyoxybutylene groups with a degree of polymerization of three or more are particularly preferred. However, from the perspective of improving durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), a degree of polymerization of 1,000 or less is preferred. For example, when polyoxyethylene-polyoxypropylene or polyoxyethylene-polyoxybutylene is used as an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, the polyoxypropylene group and polyoxybutylene group can also function as hydrophobic groups.

This polyoxyalkylene group having 3 or more carbon atoms may or may not have a substituent. Examples of such substituents include alkyl groups, cycloalkyl groups, aralkyl groups, and aryl groups.

As the alkyl group as a substituent on a polyoxyalkylene group having 3 or more carbon atoms, an alkyl group having 1 to 6 carbon atoms is preferred, and specifically preferred are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups.

Examples of cycloalkyl groups, aralkyl groups, and aryl groups that can be used as substituents on polyoxyalkylene groups having 3 or more carbon atoms include those exemplified above.

The substituents are not limited to those mentioned above, and may also have groups derived from the fluorene structure (such as fluorenyl groups). When water solubility is particularly important, phenyl groups and the like are preferred as substituents. When compatibility with flaky carbon and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping properties, etc.) are particularly important, naphthyl groups, fluorenyl groups and the like are preferred as substituents.

From the standpoints of affinity with carbon and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), aryl groups and polyoxyalkylene groups having 3 or more carbon atoms are preferred, with aryl groups being more preferred, and aryl groups having two or more aromatic rings (fused aryl groups and polycyclic aryl groups) being even more preferred. Specific examples of preferred hydrophobic groups include naphthyl groups, anthracenyl groups, tetracenyl groups, phenanthrenyl groups, biphenyl groups, terphenyl groups, fluorenyl groups, acenaphthenyl groups, acenaphthylenyl groups, pyrenyl groups, chrysenyl groups, triphenylenyl groups, polyoxypropylene groups with a degree of polymerization of 4 or more, and polyoxybutylene groups with a degree of polymerization of 3 or more.

The hydrophilic group possessed by the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon is not particularly limited as long as it can increase the solubility in water of the organic compound having the hydrophilic group and a hydrophobic group with high affinity for carbon. However, from the viewpoint of improving the water solubility of the organic compound having the hydrophilic group and a hydrophobic group with high affinity for carbon, the dispersibility of the flaky carbon, and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferable to use a hydrophilic group possessing a hydrophilic group and a hydrophobic group with high affinity for carbon, which has general formulas (1) to (4):

[In the formula, —OH represents an alcoholic hydroxyl group or a phenolic hydroxyl group. R represents a divalent organic group. ^X1 represents a hydrogen atom, an alkali metal, _NH4 , or an organic ammonium group. ^X2 represents a hydrogen atom, an alkali metal, _NH4 , an organic ammonium group, or an alkyl group. The oxygen atom in general formula (2) is an ether bond.]
A hydrophilic group represented by the following formula is preferred. An organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon can contain one or more of such hydrophilic groups. When a plurality of hydrophilic groups are used, a plurality of the same hydrophilic groups may be used, a plurality of hydrophilic groups represented by the same general formula may be used, or a plurality of hydrophilic groups represented by different general formulas may be used.

In general formula (1), -OH can be either an alcoholic hydroxyl group or a phenolic hydroxyl group. From the standpoints of improving the water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, the dispersibility of flaky carbon, and durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), alcoholic hydroxyl groups are preferred. However, when a phenolic hydroxyl group is included (especially when multiple phenolic hydroxyl groups are included), it inevitably also contains a benzene ring, which has excellent hydrophobic properties, and as a whole, it is particularly likely to improve durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

In particular, compounds containing a benzenetriol structure (such as a pyrogallol structure, a hydroxyquinol structure, or a phloroglucinol structure) or a benzenediol structure (such as a catechol structure, a resorcinol structure, or a hydroquinone structure) (especially those containing two or more of these) are particularly excellent in strengthening properties, such as improving durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). As organic compounds containing hydrophilic groups with such structures and hydrophobic groups with high affinity for carbon, not only artificially synthesized compounds but also naturally occurring polyphenols are particularly suitable.

Polyphenols are a general term for compounds also known as polyhydric phenols, and refer to compounds in which two or more hydrogen atoms of an aromatic hydrocarbon have been replaced with hydroxyl groups, or mixtures thereof. Examples of such polyphenols include, but are not limited to, catechins (epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), quercetin, hesperidin, tannic acid, theaflavin, procyanidins, leucoanthocyanidins, and rutin. Among these, tannic acid and catechins (e.g., green tea polyphenols) are preferred from the standpoint of strengthening properties such as improved water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, improved dispersibility of flaky carbon, and improved durability against resins (e.g., light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability).

Since these polyphenols are found in many plants, the plants may be used as they are, or plant extracts may be used. Alternatively, the polyphenols may be purified using standard methods before use. It is particularly preferable to use purified products (such as purified alcohols) because they are more likely to provide benefits such as improved water solubility for organic compounds that have stable hydrophilic groups and hydrophobic groups with high affinity for carbon, improved dispersibility of flaky carbon, and improved durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

In general formula (2), the divalent organic group represented by R is not particularly limited, but a divalent hydrocarbon group is preferred. Examples of divalent hydrocarbon groups include aliphatic hydrocarbon groups (such as alkylene groups (or alkylidene groups), cycloalkylene groups, alkylene (or alkylidene)-cycloalkylene groups, and bi- or tricycloalkylene groups), and aromatic hydrocarbon groups (such as arylene groups and alkylene (or alkylidene)-arylene groups).

In general formula (2), the alkylene group (or alkylidene group) represented by the group R is preferably an alkylene group, more preferably a _C1-8 alkylene group, even more preferably a _C1-4 alkylene group, particularly preferably a _C2-4 alkylene group, and most preferably a _C2-3 alkylene group. Specific examples include a methylene group, an ethylene group, an ethylidene group, a trimethylene group, a propylene group, a propylidene group, a tetramethylene group, an ethylethylene group, a butan-2-ylidene group, a 1,2-dimethylethylene group, a pentamethylene group, and a pentane-2,3-diyl group.

In general formula (2), the cycloalkylene group represented by group R is preferably a C _5-10 cycloalkylene group, more preferably a C _5-8 cycloalkylene group. Specific examples include a cyclopentylene group, a cyclohexylene group, a methylcyclohexylene group, and a cycloheptylene group.

In general formula (2), the alkylene (or alkylidene)-cycloalkylene group represented by the group R is preferably an alkylene-cycloalkylene group, more preferably a _C1-6 alkylene- _C5-10 cycloalkylene group, and even more preferably a _C1-4 alkylene- _C5-8 cycloalkylene group. Specific examples include a methylene-cyclohexylene group, an ethylene-cyclohexylene group, an ethylene-methylcyclohexylene group, and an ethylidene-cyclohexylene group.

In general formula (2), specific examples of the bicycloalkylene or tricycloalkylene group represented by the group R include norbornane-diyl groups.

In general formula (2), the arylene group represented by group R is preferably a C _6-10 arylene group, specifically exemplified by a phenylene group and a naphthalenediyl group.

In general formula (2), the alkylene (or alkylidene)-arylene group represented by the group R is preferably an alkylene-arylene group, more preferably a _C1-6 alkylene- _C6-20 arylene group, still more preferably a _C1-4 alkylene- _C6-10 arylene group, and particularly preferably a _C1-2 alkylene-phenylene group. Specific examples include a methylene-phenylene group, an ethylene-phenylene group, an ethylene-methylphenylene group, and an ethylidenephenylene group.

Of these, divalent aliphatic hydrocarbon groups, particularly alkylene groups (for example, C _1-4 alkylene groups such as methylene and ethylene groups) are preferred.

Note that the alkylene (or alkylidene)-cycloalkylene group and alkylene (alkylidene)-arylene group refer to a group represented by -Ra-Rb- (where Ra represents an alkylene group or alkylidene group bonded to different oxygen atoms in general formula (2), and Rb represents a cycloalkylene group or arylene group).

The hydrophilic group represented by general formula (2) is not particularly limited, and examples thereof include -OC ₂ H ₄ O-, -OC ₃ H ₆ O-, and -OCH ₂ O-. Groups having a plurality of these groups (preferably 3 to 100 groups) can also be preferably used, and examples of such groups include trioxyethylene, tetraoxyethylene, polyoxymethylene, polyoxyethylene, and polyoxypropylene. In particular, when the hydrophilic group represented by general formula (2) has a structure in which three or more hydrophilic groups have been polymerized, the more carbon atoms in R (for example, three or more carbon atoms), the more likely the hydrophilicity is to decrease and the more likely the hydrophobicity is to increase. Therefore, -OC ₂ H ₄ O- and -OCH ₂ O- are preferred, as they tend to retain their hydrophilicity even with an increased degree of polymerization.

When the compound contains a hydrophilic group represented by general formula (2), particularly a polyoxyalkylene group, or even a polyoxyethylene group, it exhibits particularly excellent reinforcing properties, such as improved durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

In the general formula (3), the alkali metal represented by X ¹ is not particularly limited, and examples thereof include sodium, potassium, and lithium.

In the general formula (3), the organic ammonium represented by ^X1 is preferably a quaternary ammonium, and tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, etc. can be suitably used.

The hydrophilic group represented by general formula (3) is not particularly limited, and examples _thereof include _-SO3 ^- H ⁺ , _-SO3 ^- Na ⁺ , -SO3 ^- K ⁺ , _-SO3 ^- _Li ⁺ , _-SO3 ^- _NH4 ⁺ , -SO3 ^- N( _CH3 ) ₄₊ ^, _-SO3 ^- N( _C2H5 ) ₄₊ ^, _{-SO3 -} ^N _{( C3H7} ) ₄₊ ^{, and} _-SO3 ^- _N ( _C4H9 ) ₄₊ .

In the general formula (4), examples of the alkali metal and organic ammonium represented by ^X2 include those exemplified above.

In general formula (4), the alkyl group represented by ^X2 may be a linear alkyl group or a branched alkyl group, but a linear alkyl group is preferred from the viewpoint of affinity with carbon and strengthening properties such as improved durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). In addition, the number of carbon atoms in the alkyl group is preferably 1 to 2 from the viewpoint of improved affinity with carbon and strengthening properties such as improved durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

The hydrophilic group represented by such general formula (4) is not particularly limited, but examples thereof include -COOH, -COONa, -COOK, -COOLi, -COONH ₄ , -COON(CH ₃ ) ₄ , -COON(C ₂ H ₅ ) ₄ , -COON(C ₃ H ₇ ) ₄ ⁺ , and -COON(C ₄ H ₉ ) ₄ ⁺ .

Among these hydrophilic groups, hydrophilic groups represented by general formula (1) or (2) are preferred from the viewpoints of improving the water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, pH-independent stability, dispersibility of flaky carbon, and durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

However, when a compound has multiple identical hydrophilic groups represented by general formula (2), i.e., a polymerized structure, the hydrophilicity of the water-soluble compound increases as the degree of polymerization increases for compounds with two or fewer carbon atoms, but the hydrophobicity of compounds with three or more carbon atoms may increase as the degree of polymerization increases.

Furthermore, in the present invention, when a nonionic material (such as a nonionic surfactant) is used as the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, its HLB value is preferably 12 or more, and more preferably 13 to 19, from the viewpoint of strengthening properties such as the water solubility of the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, the dispersibility of the flaky carbon, and improved durability against resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). Furthermore, when the hydrophobic group is the same (when the affinity with the flaky carbon is about the same), the higher the HLB value, the better.

There are no particular limitations on the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon that meets the above conditions. Either aromatic or non-aromatic water-soluble compounds may be used, with aromatic water-soluble compounds being preferred. Examples of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon include polyoxyethylene lauryl ether, polyoxyethylene decyl ether, polyoxypropylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene naphthyl ether, polyoxypropylene lauryl ether, polyoxypropylene naphthyl ether, polyoxyethylene myristyl ether, polyoxypropylene myristyl ether, polyoxyethylene cetyl ether, polyoxypropylene cetyl ether, polyoxyethylene octylphenyl ether, polyoxypropylene octylphenyl ether, polyoxyethylene undecylphenyl ether, polyoxypropylene undecylphenyl ether, polyoxyethylene tridecylphenyl ether, and polyoxypropylene tridecylphenyl ether. phenyl ether, polyoxyethylene pentadecyl phenyl ether, polyoxypropylene pentadecyl phenyl ether, polyoxyethylene polyoxypropylene glycol, polyoxypropylene polyglyceryl ether, sodium cholate, potassium cholate, sodium dodecyl sulfonate, potassium dodecyl sulfonate, sodium dilauramidoglutamide lysine, potassium dilauramidoglutamide lysine, decaglycerin laurate, n-decyl alcohol, catechins (green tea polyphenols, etc.; epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), quercetin, hesperidin, tannic acid, theaflavin, procyanidins, leucoanthocyanidins, rutin, etc.

Examples of organic compounds having such hydrophilic groups and hydrophobic groups with high affinity for carbon include Emulgen 103, Emulgen 104P, Emulgen 105, Emulgen 106, Emulgen 108, Emulgen 109P, Emulgen 120, Emulgen 123P, Emulgen 130K, Emulgen 147, Emulgen 150, Emulgen 210P, and Emulgen 220 (all polyoxyethylene alkyl ethers manufactured by Kao Corporation), Triton X-100, Triton X-114, and Triton X-3. 05, Triton X-405 (polyoxyethylene octylphenyl ethers manufactured by Dow Chemical), Noigen EN, Noigen EN-10 (polyoxyethylene naphthyl ethers manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), tannic acid, catechins (including polyphenols such as epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallocatechin, catechin gallate, and gallocatechin gallate), gallic acid, gallic acid esters, and persimmon tannins (including tannins) can be used.

The content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the durability improver of the present invention is not particularly limited, but from the viewpoint of strengthening properties such as improved durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferably 5 to 90 mass% and more preferably 10 to 85 mass% based on 100 mass% of the total amount of the durability improver of the present invention. Furthermore, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the durability improver of the present invention is not particularly limited, but from the viewpoint of strengthening properties such as improved durability to resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferably 1 to 1,000 mass parts and more preferably 2 to 500 mass parts per 100 mass parts of flaky carbon. In addition, when prioritizing thermal conductivity to the resin, radical trapping effect, light resistance, etc., the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is preferably low, and is preferably 1 to 50 mass% and more preferably 2 to 35 mass% relative to 100 mass% of the total amount of the durability improver of the present invention. Similarly, when prioritizing thermal conductivity to the resin, radical trapping effect, light resistance, etc., the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is preferably low, and the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the durability improver of the present invention is preferably 1 to 100 mass parts and more preferably 2 to 50 mass parts relative to 100 parts by mass of the flaky carbon. Furthermore, when prioritizing antioxidant effect, dispersibility of the flaky carbon, etc., the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is preferably high, and is preferably 10 to 90 mass% and more preferably 25 to 85 mass% relative to 100 mass% of the total amount of the durability improver of the present invention. Similarly, when prioritizing thermal conductivity to the resin, radical trapping effect, light resistance, etc., it is preferable to have a low content of organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon. The content of organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon in the durability improver of the present invention is preferably 10 to 1,000 parts by mass, and more preferably 33 to 500 parts by mass, per 100 parts by mass of flaky carbon.

When the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is low, the durability improver of the present invention has a configuration in which the surface of the flaky carbon is coated with an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon (Figure 1). On the other hand, when the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is high, the durability improver of the present invention has a configuration in which the flaky carbon is dispersed in an organic compound having a hydrophobic group with a high affinity for carbon (Figure 2). In either case, the presence of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon around the flaky carbon suppresses aggregation of the flaky carbon, resulting in a material that can improve the durability of the resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

(1-3) Other Components The durability improver of the present invention may contain other components in addition to the flaky carbon and the organic compound having a hydrophilic group and a hydrophobic group that has high affinity with carbon. Examples of such other components include carbon fiber (particularly, carbon nanofibers having a fiber diameter of 500 nm or less), activated carbon, carbon black (acetylene black, oil furnace black, etc.; particularly, ketjen black, which has high conductivity and a large specific surface area), glassy carbon, carbon microcoils, fullerene, biomass-based carbon materials (those made from bagasse, sorghum, wood chips, sawdust, bamboo, bark, rice straw, rice husks, coffee grounds, used tea leaves, soybean pulp refuse, rice bran, pulp waste, etc.; carbon fiber produced from lignin, etc.), cellulose nanofibers, boron nitride, molybdenum compounds (molybdenum disulfide, organic molybdenum, etc.), tungsten disulfide, melamine cyanurate, phthalocyanine, lead oxide, calcium fluoride, and layered minerals (mica, talc, etc.).

However, from the standpoint of making the durability improver of the present invention more easily dispersible in the resin, further improving the uniformity and adhesion of the coating film when applied, and further enhancing its reinforcing properties, such as improving its durability to the resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferable that the content of other components be small, and preferably 0.01 to 10% by mass, and more preferably 0.02 to 5% by mass, of the total amount of the durability improver of the present invention taken as 100% by mass.

The form of the durability improver of the present invention is not particularly limited, and examples include a coating film, a sheet, a mass, etc.

As described above, the durability improver of the present invention is a material that is easily dispersed in resin and can enhance the durability of the resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.). Compared to conventional additives, which have reduced durability, this is a material that is advantageous for improving the durability of resins (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

Such durability improvers of the present invention (light resistance improvers, heat resistance improvers, antioxidants, acid resistance improvers, water resistance improvers, radical trap resistant agents, etc.) can be used in applications such as various injection molded products, extrusion molded products, sheet molded products, blow molded products, compression molded products, and various paints (including paints with functions such as electrical conductivity, heat conduction, electromagnetic wave shielding, lubrication, and abrasion resistance, as well as paints used for ordinary rust prevention and coloring).

2. Method for Producing Durability Improver The durability improver of the present invention can be produced, for example, by
(1) It can be produced by a process of removing the solvent from a dispersion containing flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having high affinity with carbon, and a solvent.

(2-1) Dispersion (flaky carbon dispersion)
In a dispersion (flaky carbon dispersion) containing flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon, and a solvent, the above-mentioned explanations can be applied to the flaky carbon and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon. In addition, the flaky carbon dispersion can contain other components as needed.

This flaky carbon dispersion may be formed as a dispersion liquid, or may be formed as a coating film on a substrate. In this case, it is preferable to use water as the main solvent used to prepare the flaky carbon dispersion (flaky carbon dispersion liquid or flaky carbon coating film), from the standpoint of improving the dispersibility of the flaky carbon and the durability of the resulting durability improver (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

The water content in the solvent used is not particularly limited, but from the standpoint of improving the dispersibility of the flaky carbon and the durability of the resulting durability improver (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), the water content is preferably 70% by mass or more (70 to 100% by mass), and more preferably 75 to 100% by mass, based on 100% by mass of the total amount of solvent.

In the present invention, only water may be used as the solvent, and organic solvents are not necessarily required. However, to further improve the solubility in water of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, organic solvents such as monohydric alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; polyhydric alcohols such as ethylene glycol and glycerin; and 2-methoxyethanol may be used.

The content of the organic solvent in the solvent used is preferably 30% by mass or less (0 to 30% by mass), and more preferably 5 to 25% by mass, based on 100% by mass of the total amount of solvent, from the standpoints of improving the solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, and improving the durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.) of the resulting durability improver.

In the above-mentioned flaky carbon dispersion, the content of flaky carbon is not particularly limited, but from the viewpoint of easily incorporating it into the composition of the durability improver of the present invention, it is preferably 50% by mass or less, more preferably 0.0001 to 40% by mass, and even more preferably 0.001 to 30% by mass, of the total amount of the flaky carbon dispersion taken as 100% by mass. Similarly, the content of the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon is not particularly limited, but from the viewpoint of easily incorporating it into the composition of the durability improver of the present invention, it is preferably 0.00001 to 70% by mass, more preferably 0.0001 to 50% by mass, and even more preferably 0.01 to 30% by mass, of the total amount of the flaky carbon dispersion taken as 100% by mass. Similarly, the content of the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon in the flaky carbon dispersion is not particularly limited, but from the viewpoint of easily incorporating it into the composition of the durability improver of the present invention, it is preferably 5 to 1,000 parts by mass, and more preferably 10 to 500 parts by mass, per 100 parts by mass of flaky carbon. Furthermore, the content of the solvent is not particularly limited, but from the viewpoint of easily incorporating it into the composition of the durability improver of the present invention, it is preferably 40 to 99.9998% by mass, more preferably 63 to 99.998% by mass, and even more preferably 85 to 99.98% by mass, of the total amount of the flaky carbon dispersion as 100% by mass.

(2-2) Method for Producing Flaky Carbon Dispersion In the present invention, the method for producing the flaky carbon dispersion is not particularly limited, and it is also possible to add flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon to a solvent. Specifically, flaky carbon can be added to a dispersion of an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, or an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be added to a dispersion of flaky carbon. Furthermore, flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be simultaneously added to a solvent.

However, from the perspective of further improving the dispersibility of the flaky carbon, making it less likely to aggregate, and further enhancing the durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.) of the resulting durability improver of the present invention, it is preferable to place a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon between a rotating turntable and a turntable placed approximately parallel to the turntable, and to apply shear to the carbonaceous material in the composition while adjusting the shortest distance between the turntable and the turntable to 200 μm or less (grinding method).

Flat carbon dispersions can also be preferably produced by applying a pressure of 30 MPa or more to a composition containing a carbonaceous material with a layered structure and an organic compound having hydrophilic groups and hydrophobic groups that have a high affinity for carbon (high-pressure dispersion method).

Conventionally, when producing flaky carbon using a wet method, a reduction treatment was applied to an aqueous dispersion containing flaky carbon oxide and an aqueous solvent. However, this method made it difficult to maintain the graphene structure, and the resulting flaky carbon severely aggregated, making it difficult to obtain a flaky carbon aqueous dispersion. There were also safety issues. In contrast, the present invention uses an organic compound having hydrophilic groups and hydrophobic groups with high affinity for carbon, allowing the flaky carbon to be obtained in a uniformly dispersed state (flaky carbon dispersion) while maintaining the graphene structure, without agglomeration. The resulting flaky carbon is also less likely to be destroyed, can be obtained in a short period of time, and is less likely to leave any clumps that failed to peel. In this case, the organic compound having hydrophilic groups and hydrophobic groups with high affinity for carbon can also function as a dispersant to uniformly disperse the flaky carbon.

Furthermore, with the shearing method, the direction of force application is parallel to the surface direction of the carbonaceous material having a layered structure, and processing is carried out in a narrow space. This results in less breakage and allows for larger-sized flake carbon (e.g., flake carbon with a size of 1 μm or more) to be obtained compared to conventional manufacturing methods using high-speed stirring, ultrasonic processing, etc., and the peeling is efficient, allowing processing to be carried out in a short time (few passes), while also leaving fewer thick lumps that were not peeled.

Carbonaceous material having a layered structure The carbonaceous material having a layered structure is not particularly limited, and examples thereof include natural graphite, artificial graphite, expanded graphite, amorphous graphite, and graphite oxide. Graphite oxide can be graphite oxidized with one or more oxidizing agents, such as sulfuric acid, nitric acid, potassium permanganate, and hydrogen peroxide. For example, when graphite oxide is obtained by the Hummers process, graphite is immersed in concentrated sulfuric acid, potassium permanganate is added to oxidize the graphite, and the reaction product is quenched with dilute sulfuric acid and/or hydrogen peroxide, and then washed with distilled water, whereby oxygen atoms are bonded to carbon atoms, introducing oxygen atoms between layers to obtain graphite oxide.

In particular, when attempting to obtain highly pure flaky carbon that does not contain heteroatoms such as oxygen, it is preferable to use graphite as the raw material, with natural graphite and expanded graphite being more preferable. When using expanded graphite, it is preferable to use expanded graphite that has less oxidation of the graphene structure. When using expanded graphite, it may be heat-treated at approximately 300 to 1000°C for 10 seconds to 5 hours before use. This makes it possible to obtain expanded graphite that has been appropriately expanded.

Graphite oxide may also be used when ease of production is important. The use of graphite oxide allows solvent molecules to easily intercalate between layers, facilitating exfoliation only in the layer direction, improving exfoliation efficiency and dispersibility, and enabling shorter processing times. However, when graphite oxide is used, a subsequent reduction treatment is required, and from the perspective of better maintaining the graphene structure, conductivity, and strength, other materials (natural graphite, artificial graphite, expanded graphite, amorphous graphite) are preferred.

On the other hand, amorphous graphite can also be used to further improve dispersibility. However, from the standpoint of crystallinity, purity, and structural maintenance, other materials (natural graphite, artificial graphite, expanded graphite, graphite oxide) are preferred.

In addition, if the crystallinity, strength, and structural integrity of the resulting flaky carbon are important, artificial graphite can also be used.

In the present invention, the content of the carbonaceous material having a layered structure in a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon is not particularly limited. However, it is preferably 50% by mass or less, more preferably 0.0001 to 40% by mass, and even more preferably 0.001 to 30% by mass, based on 100% by mass of the total amount of the composition used to produce the flaky carbon dispersion. Note that a lower content of the carbonaceous material having a layered structure makes exfoliation (delamination) more likely to occur, resulting in more efficient production of flaky carbon and fewer processing cycles. It also tends to maintain an appropriate viscosity and facilitate shearing and other processes. On the other hand, a higher content of the carbonaceous material having a layered structure results in better productivity. Therefore, it is preferable to appropriately set the content of the carbonaceous material having a layered structure from the perspective of balancing exfoliation efficiency, viscosity, productivity, and other factors. Note that when a carbonaceous material dispersion is used, it is preferable to keep the content of the carbonaceous material having a layered structure in the flaky carbon dispersion within the above range.

Organic Compound Having a Hydrophilic Group and a Hydrophobic Group with High Affinity for Carbon As the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, those mentioned above can be used.

In the present invention, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the composition used to produce the flaky carbon dispersion is not particularly limited, but is preferably 0.00001 to 70% by mass, more preferably 0.001 to 50% by mass, and even more preferably 0.01 to 30% by mass, based on 100% by mass of the total amount of the composition used to produce the flaky carbon dispersion. Meanwhile, in the present invention, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the composition used to produce the flaky carbon dispersion is preferably 5 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, per 100 parts by mass of the carbonaceous material having a layered structure. Note that the lower the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the higher the content of the carbonaceous material having a layered structure, which tends to improve the durability of the resin (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.) and makes it easier to process inexpensively. On the other hand, a higher content of organic compounds having hydrophilic groups and hydrophobic groups with a high affinity for carbon tends to result in more efficient production of flaky carbon because exfoliation (delamination) occurs more easily. However, higher viscosity may also result in lower exfoliation efficiency. Therefore, it is preferable to appropriately set the content of organic compounds having hydrophilic groups and hydrophobic groups with a high affinity for carbon from the perspective of balancing durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), cost, exfoliation efficiency, etc. In addition, when a carbonaceous material dispersion is used in this production method, it is preferable to set the content of organic compounds having hydrophilic groups and hydrophobic groups with a high affinity for carbon in the carbonaceous material dispersion within the above-mentioned range.

In the method for producing the flaky carbon dispersion described above , as described above, it is preferable to perform a specific treatment using a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon. However, from the viewpoint of improving the exfoliation efficiency of the carbonaceous material having a layered structure and the durability of the resulting durability improver (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferable to perform a specific treatment on a carbonaceous material dispersion containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon.

This carbonaceous material dispersion may be formed as a dispersion liquid or as a coating film on a substrate.

In this case, the solvents used to prepare the carbonaceous material dispersion (carbonaceous material dispersion liquid or carbonaceous material coating film) can be those described above.

In the present invention, when a specific process is performed using a carbonaceous material dispersion that uses a solvent, the total amount of solvent in the carbonaceous material dispersion is not particularly limited. However, from the viewpoints of the exfoliation efficiency of the carbonaceous material having a layered structure, the solubility of organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon, and the like, the total amount of solvent is preferably 40 to 99.9998 mass%, more preferably 63 to 99.998 mass%, and even more preferably 85 to 99.98 mass%, of which the total amount of the carbonaceous material dispersion is taken as 100 mass%.

In the present invention, when a specific process is performed using a carbonaceous material dispersion using a solvent, the carbonaceous material dispersion may be prepared by adding a carbonaceous material having a layered structure to an organic compound dispersion having hydrophilic groups and hydrophobic groups that have a high affinity for carbon, or by adding an organic compound having hydrophilic groups and hydrophobic groups that have a high affinity for carbon to a carbonaceous material dispersion having a layered structure. Alternatively, a carbonaceous material having a layered structure and an organic compound having hydrophilic groups and hydrophobic groups that have a high affinity for carbon may be simultaneously added to a solvent.

Other Components In the present invention, other components may be contained in a composition (e.g., a carbonaceous material dispersion) containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon. This allows these other components to be contained in the final flaky carbon dispersion or durability improver. The above-mentioned components can be used as such other components, and they may be used within a range that does not impair the effects of the present invention. However, from the viewpoint of easily dispersing the other components in a resin and easily obtaining a durability improver that further improves the uniformity, adhesion, and durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.) of the coating film upon application, the content of the other components is preferably small, and is preferably 0.00001 to 5 mass %, and more preferably 0.0001 to 2 mass %, of the total amount of the carbonaceous material dispersion taken as 100 mass %.

Shearing treatment (grinding method)
In the present invention, when the attrition method is adopted, as described above, it is preferable to place a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon between a rotating turntable and a turntable placed approximately parallel to the turntable, and to perform a process of applying shear to the carbonaceous material in the composition while adjusting the shortest distance between the turntable and the turntable to 200 μm or less. Note that, when a carbonaceous material dispersion is used, it is preferable to place the carbonaceous material dispersion between a rotating turntable and a turntable placed approximately parallel to the turntable, and to perform a process of applying shear to the carbonaceous material in the carbonaceous material dispersion while adjusting the shortest distance between the turntable and the turntable to 200 μm or less.

Shearing treatment results in the atomization of the carbonaceous material having a layered structure. While this may result in the graphene structure not being maintained depending on the conditions, it can efficiently exfoliate the carbonaceous material having a layered structure and reduce processing time. During this shearing treatment, the rotating disk and the disk are positioned approximately parallel, but they do not need to be strictly parallel. Specifically, the angle between the axis perpendicular to the rotating disk and the axis perpendicular to the disk is preferably 10° or less, more preferably 5° or less. It is most preferable that the axis perpendicular to the rotating disk and the axis perpendicular to the disk are strictly parallel. The minimum distance between two surfaces during this shearing treatment is not particularly limited as long as it can sufficiently exfoliate the carbonaceous material having a layered structure; however, it is preferably 200 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The shorter the minimum distance between two surfaces during shearing treatment, the higher the exfoliation efficiency; it is typically 0 μm. In the present invention, the shortest distance between the two surfaces during shearing refers to the distance obtained by subtracting the thickness of the composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon from the measured shortest distance between the turntables. In other words, a measured shortest distance of 0 μm between the turntables means that the composition containing the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is placed in close contact between the turntables and the disks. In other words, no space exists between the turntables and the disks other than the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon. Although the turntables and the disks are arranged approximately parallel, the distance between the turntables and the disks may vary depending on the location. In this case, the shortest distance between the turntables and the disks refers to the shortest distance between the turntables and the disks. Furthermore, it is not necessary to separate the turntables beforehand; the material to be processed may be sandwiched between the turntables, or the turntables and the disks may be in contact with each other, causing the gap between the turntables and the disks to widen as the carbonaceous material having a layered structure is sandwiched between them. Such shearing treatment can be performed using any device that has a mechanism for rotating a disk-shaped object, such as a millstone, a vibration mixer, a spin coater, or a grinder.

There are no particular restrictions on the size of the turntable and the disc that can be used in this case, with a size of 5 to 500 mm being preferred, and 10 to 200 mm being more preferred. There are also no particular restrictions on the rotation speed of the turntable when performing the shearing treatment, and it is preferable to set it within a range that can sufficiently flake the carbonaceous material having a layered structure; for example, 1,000 to 10,000 ppm is preferred, and 1,500 to 3,000 ppm is more preferred.

By performing this type of shearing treatment, the plate and the carbonaceous material having a layered structure, and the carbonaceous material having a layered structure and the carbonaceous material having a layered structure can be brought into contact with each other, and shear can be applied to the carbonaceous material having a layered structure in a direction parallel to the graphene layers of the carbonaceous material having a layered structure.

By reducing the shortest distance between the rotating discs during shearing and increasing the rotation speed of the rotating discs, it is possible to make the conditions stronger, allowing the layered carbonaceous material to be flaked more efficiently and reducing the processing time. This shearing operation can be performed one or more times, preferably three or more times.

There are no particular restrictions on the temperature at which the shearing treatment is carried out, as long as it is a temperature that can sufficiently exfoliate the carbonaceous material having a layered structure, and it can be 0°C or higher, preferably 0 to 100°C, and particularly 20 to 95°C. The temperature at which the shearing treatment is carried out is preferably one that provides high solubility for organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon. If higher temperatures increase solubility, higher temperatures are preferred. If a water-soluble compound with a cloud point is used, it is preferable to maintain the temperature below the cloud point.

Before carrying out the shearing treatment, in order to bring the carbonaceous material having a layered structure into intimate contact with the organic compound having hydrophilic groups and hydrophobic groups that have a high affinity for carbon, the materials may be stirred in advance using a stirring device, ultrasonic dispersion device, or the like before preparing the composition, allowing the organic compound having hydrophilic groups and hydrophobic groups that have a high affinity for carbon to blend with the surface of the carbonaceous material having a layered structure.

In the present invention, when graphite oxide is used as the carbonaceous material having a layered structure, it exists as a flaky carbon oxide in the dispersion after the shearing treatment. Therefore, when graphite oxide is used as the carbonaceous material having a layered structure, it is preferable to perform a reduction treatment as a post-treatment. Various methods, such as chemical reduction and electrochemical reduction, can be used for the reduction treatment, but chemical reduction is preferred. Among these, chemical reduction using a reducing agent such as hydrazine or sodium borohydride is preferred. The amount of reducing agent is preferably 1 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 50 to 300 parts by mass, per 100 parts by mass of flaky carbon oxide. Furthermore, heating during reduction facilitates the reduction. The heating temperature is preferably 40 to 200°C, more preferably 50 to 150°C, and even more preferably 60 to 120°C. The reduction time is preferably 10 minutes to 64 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 to 24 hours. However, it is preferable to do so to the extent that the graphene structure is not excessively destroyed.

The above-described manufacturing method can produce flaky carbon as the above-described flaky carbon dispersion. Because this manufacturing method contains an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the flaky carbon dispersion also contains an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon. This organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can adsorb to the surface of the flaky carbon and isolate and disperse the flaky carbon at a high concentration in the solvent, thus functioning as a dispersant in the flaky carbon dispersion. Furthermore, the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be commercially available, offering advantages over conventional products in both cost and dispersibility. Furthermore, by remaining on the surface of the flaky carbon, the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can exhibit sufficient durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.).

Furthermore, in conventional methods involving oxidation and reduction, it was impossible to form a flaky carbon dispersion on a plastic substrate because the plastic substrate was hydrolyzed during the reduction treatment and the flaky carbon aggregated when the reduction treatment was performed, making it impossible to exist as a dispersion. However, in the present invention, by incorporating an organic compound having the above-mentioned hydrophilic group and a hydrophobic group that has a high affinity for carbon and performing a specific treatment, it is possible to form a flaky carbon dispersion on a plastic substrate such as polyethylene terephthalate (PET) without the substrate being hydrolyzed.

Pressure treatment (high pressure dispersion method)
In the present invention, when the high-pressure dispersion method is adopted, as described above, it is preferable to subject a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has high affinity for carbon to a pressure treatment of 30 MPa or more.

Pressure treatment causes the carbonaceous material having a layered structure to become finer. While this may result in the graphene structure not being maintained depending on the conditions, it can efficiently flaking the carbonaceous material having a layered structure and reduce processing time. There are no particular restrictions on the pressure level used when performing this type of pressure treatment, as long as it is sufficient to flaking the carbonaceous material having a layered structure. However, a pressure of 30 MPa or higher is preferred, with 50 to 400 MPa being more preferred, and 100 to 300 MPa being even more preferred. This type of pressure treatment can be performed using a high-pressure dispersion device, a supercritical water production device, or the like. High-pressure dispersion devices can disperse the material by applying mechanical pressure, and supercritical water production devices can increase the pressure of the system by heating the water.

Such pressure can, for example,
(i) causing two or more of the carbonaceous material dispersions to collide with each other;
(ii) causing the carbonaceous material dispersion to collide with a metal or ceramic material (a high-hardness material such as silicon carbide or alumina);
(iii) A treatment such as passing the carbonaceous material dispersion through a space having a cross-sectional area of 1 ^cm2 or less may be carried out.

According to (i) and (ii) above, it is possible to apply stronger pressure conditions, which allows the carbonaceous material having a layered structure to be flaked more efficiently and the processing time to be reduced. Furthermore, according to (iii) above, the carbonaceous material having a layered structure can be flaked more appropriately while better maintaining the graphene structure. This pressure operation can be performed one or more times, preferably ten or more times.

There are no particular restrictions on the pressurizing temperature, as long as it is a temperature that can sufficiently exfoliate the carbonaceous material having a layered structure. In the cases of (i) and (ii) above, it can be 0 to 100°C, particularly 20 to 95°C. In the case of (iii) above, if pressure is applied mechanically, 0 to 100°C is preferred, and if pressure is generated by the supercritical state of water, 373 to 700°C is preferred, and 380 to 450°C is more preferred.

When carrying out the pressure treatment, it is preferable to carry out ultrasonic dispersion treatment as a preliminary treatment (pretreatment) to atomize the carbonaceous material having a layered structure. This can have the effect of preventing clogging, etc.

There are no particular restrictions on the output power used in ultrasonic dispersion treatment, but from the perspective of flaking carbonaceous materials having a layered structure, it is preferable to use a power that is more powerful than the power typically used in ultrasonic dispersion treatment (approximately 40 to 50 W). Specifically, the output power of the ultrasonic dispersion treatment is preferably 100 W or more, more preferably 300 to 20,000 W, and even more preferably 400 to 18,000 W.

There are no particular restrictions on the ultrasonic dispersion temperature, as long as it is a temperature that can sufficiently exfoliate the carbonaceous material having a layered structure, and it can be 0 to 80°C, particularly 10 to 70°C. There are no particular restrictions on the ultrasonic dispersion time, as long as it is a time that can sufficiently exfoliate the carbonaceous material having a layered structure, and it can be 1 to 600 minutes, particularly 3 to 120 minutes.

In addition, as a pre- or post-treatment of these processes, dispersion treatment using other dispersion devices such as conventional mechanical stirring, dispersion treatment using an emulsifier, or dispersion treatment using a bead mill may be used in combination.

In the present invention, when graphite oxide is used as the carbonaceous material having a layered structure, it exists as a flaky carbon oxide in the dispersion that has been subjected to the above-mentioned pressure treatment. Therefore, when graphite oxide is used as the carbonaceous material having a layered structure, it is preferable to perform a reduction treatment as a post-treatment. Various methods, such as chemical reduction and electrochemical reduction, can be used for the reduction treatment, but chemical reduction is preferred. Among these, chemical reduction using a reducing agent such as hydrazine or sodium borohydride is preferred. The amount of reducing agent is preferably 1 to 1,000 parts by mass, more preferably 10 to 500 parts by mass, and even more preferably 50 to 300 parts by mass, per 100 parts by mass of flaky carbon oxide. Furthermore, heating during reduction facilitates the reduction. The heating temperature is preferably 40 to 200°C, more preferably 50 to 150°C, and even more preferably 60 to 120°C. The reduction time is preferably 10 minutes to 64 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 to 24 hours. However, it is preferable to do so to the extent that the graphene structure is not excessively destroyed.

(2-3) Method for Producing the Durability Improver of the Present Invention The durability improver of the present invention can be obtained by removing the solvent from the above-mentioned flaky carbon dispersion.

Methods for removing the solvent include concentrating the flaky carbon dispersion. This can be achieved by drying the flaky carbon dispersion, spin-coating or applying the flaky carbon dispersion onto a substrate and then drying, or recovering the thermal conductive material of the present invention through conventional solid-liquid separation. Examples of methods for solid-liquid separation include methods commonly used for solid-liquid separation, such as filtration using filter paper or a glass filter; filtration after centrifugation; and the use of a vacuum filter. Next, the drying method is not particularly limited, and examples include drying using a hot air dryer or the like at about 50 to 200°C for about 1 to 24 hours.

3. Resin Durability Improving Composition The resin durability improving composition of the present invention contains the durability improver of the present invention described above and a resin.

The durability improver of the present invention suppresses the aggregation of flaky carbon and is a material that is easily dispersed in other materials (e.g., resins, etc.). Therefore, by mixing it with other materials, it can be applied to nanocomposites containing flaky carbon, etc.

Specific examples of such other materials include resins such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, thermoplastic polyurethane resin, polyvinylidene fluoride resin, acrylonitrile-butadiene-styrene copolymer (ABS) resin, acrylonitrile-styrene copolymer (AS) resin, polymethyl methacrylate resin, polyamide resin, polyacetal resin, polycarbonate resin, polyarylate resin, polyphenylene ether resin, polyethylene terephthalate resin, polybutylene terephthalate resin, cyclic polyolefin resin, polyphenylene sulfide resin, polyether ether ketone resin, thermoplastic polyimide resin, polyamide-imide resin, and styrene-butadiene-styrene copolymer. These materials can be used alone or in combination of two or more. These other materials may be known or commercially available.

Aromatic polymer compounds are preferred as these resins, as they interact (e.g., through π-electron interaction) with the hydrophobic groups of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thereby further improving compatibility with the durability improver of the present invention. Specifically, styrene-butadiene-styrene copolymers are preferred. Furthermore, polyamide-based thermoplastic resins and thermoplastic elastomers are also preferred from the perspective of affinity with carbon materials.

In the resin durability improving composition of the present invention, the content of the above-mentioned other materials is not particularly limited, but from the viewpoint of durability (light resistance, heat resistance, oxidation resistance, acid resistance, water resistance, radical trapping ability, etc.), it is preferably 5 to 9,900 parts by mass, and more preferably 10 to 9,700 parts by mass, per 100 parts by mass of the durability improver of the present invention.

The present invention will be explained in more detail below using examples. However, the present invention is not limited to these examples.

In the following examples, the oxidation induction time refers to the time from switching the atmospheric gas from _N2 to _O2 to the rise of the exothermic peak due to oxygen absorption in DSC measurement. The obtained oxidation induction time can be used as a measure of the degree of deterioration, and a longer time indicates higher antioxidant properties and improved durability. In measuring the oxidation induction time, the measurement holding temperature is optimized taking into account the melting point and ease of oxidation of the resin.

Example 1
500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of polyoxyethylene naphthyl ether (HLB value 18), and 10,000 g of water were mixed and stirred to obtain a mixed liquid.

This mixture was sheared once for 30 minutes at 1500 rpm using a ceramic grinder with a radius of 300 mm. The minimum grinding distance of the ceramic grinder was approximately 10 μm.

1,000 g of ethanol was added to 200 g of the resulting dispersion (containing 10 g of carbon derived from graphite) and the mixture was filtered under reduced pressure. 800 g of ethanol was then added to the resulting cake and the mixture was filtered under reduced pressure. 800 g of acetone was then added to the resulting cake and the resulting cake was filtered under reduced pressure. The resulting cake was then dried at 60°C for 16 hours, yielding 51 g of a black solid.

The solid was heated to 600°C at a heating rate of 3°C/min using TG-DTA and thermal analysis revealed that the weight loss from room temperature to 450°C, due to the dispersion of polyoxyethylene naphthyl ether, was approximately 3%. Therefore, the resulting solid contained 3.1 parts by mass of tannic acid per 100 parts by mass of flaky carbon.

Furthermore, when the carbon content of the cake after the acetone washing was analyzed using a TEM, flake-like carbon approximately 10 nm thick (30 layers) was observed.

The obtained powder was added to polypropylene (BC06C manufactured by Japan Polypropylene Corporation) so as to account for 3% by mass, with the total amount of the composition being 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 180℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 38 minutes.

Example 2
500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of tannic acid (manufactured by Kishida Chemical Co., Ltd.), and 10,000 g of water were mixed and stirred to obtain a mixed liquid.

This mixture was sheared once for 30 minutes at 1500 rpm using a ceramic grinder with a radius of 300 mm. The minimum grinding distance of the ceramic grinder was approximately 50 μm.

The resulting dispersion was dried at 90°C and 30 hPa to remove the solvent (water) and obtain a powder. As a result, the resulting powder contained 50 parts by mass of tannic acid per 100 parts by mass of flaky carbon.

Separately, 50 g of ethanol was added to 10 g of the resulting dispersion and filtered under reduced pressure. 40 g of acetone was added to the resulting cake and filtered under reduced pressure. Acetone was then added to the resulting cake and filtered under reduced pressure again. The resulting black substance was analyzed by TEM, revealing flaky carbon approximately 10 nm thick (30 layers).

The obtained powder was added to polypropylene (BC06C manufactured by Japan Polypropylene Corporation) so that the amount was 7.5% by mass, assuming the total amount of the composition to be 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 180℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 96.4 minutes.

Example 3
500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of green tea polyphenol (manufactured by Pharma Foods Co., Ltd.), and 10,000 g of water were mixed and stirred to obtain a mixed liquid.

This mixture was sheared once for 30 minutes at 1500 rpm using a ceramic grinder with a radius of 300 mm. The minimum grinding distance of the ceramic grinder was approximately 50 μm.

The resulting dispersion was dried at 90°C and 30 hPa to remove the solvent (water) and obtain a powder. As a result, the resulting powder contained 50 parts by mass of green tea polyphenols per 100 parts by mass of flaky carbon.

The obtained powder was added to polypropylene (BC06C manufactured by Japan Polypropylene Corporation) so that the amount was 7.5% by mass, assuming the total amount of the composition to be 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 180℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 97.4 minutes.

Example 4
500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of tannic acid (manufactured by Kishida Chemical Co., Ltd.), and 10,000 g of water were mixed and stirred to obtain a mixed liquid.

This mixture was sheared once for 30 minutes at 1500 rpm using a ceramic grinder with a radius of 300 mm. The minimum grinding distance of the ceramic grinder was approximately 50 μm.

The resulting dispersion was dried at 90°C and 30 hPa to remove the solvent (water) and obtain a powder. As a result, the resulting powder contained 50 parts by mass of tannic acid per 100 parts by mass of flaky carbon.

The obtained powder was added to a styrene-butadiene-styrene block copolymer (Tufprene A manufactured by Asahi Kasei Chemicals Corporation) in an amount of 6% by mass, with the total amount of the composition being 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 170℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 41.4 minutes.

Example 5
500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of green tea polyphenol (manufactured by Pharma Foods Co., Ltd.), and 10,000 g of water were mixed and stirred to obtain a mixed liquid.

This mixture was sheared once for 30 minutes at 1500 rpm using a ceramic grinder with a radius of 300 mm. The minimum grinding distance of the ceramic grinder was approximately 50 μm.

The resulting dispersion was dried at 90°C and 30 hPa to remove the solvent (water) and obtain a powder. As a result, the resulting powder contained 50 parts by mass of green tea polyphenols per 100 parts by mass of flaky carbon.

The obtained powder was added to a styrene-butadiene-styrene block copolymer (Tufprene A manufactured by Asahi Kasei Chemicals Corporation) in an amount of 6% by mass, with the total amount of the composition being 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 170℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 43.3 minutes.

Comparative Example 1
Polypropylene (BC6C manufactured by Japan Polypropylene Corporation) was kneaded at 210°C using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D = 30) to obtain pellets. The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 180℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 29.2 minutes.

Comparative Example 2
PAN-based carbon nanofibers (manufactured by iCarbon Co., Ltd.) were added to polypropylene (BC06C manufactured by Japan Polypropylene Corporation) in an amount of 5% by mass, with the total amount of the composition being 100% by mass, and the mixture was kneaded using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Co., Ltd., diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 180℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 17.9 minutes.

Comparative Example 3
A styrene-butadiene-styrene block copolymer (Tufprene A manufactured by Asahi Kasei Chemicals Corporation) was kneaded at 210°C using a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D = 30) to obtain pellets. The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 170℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 15.4 minutes.

Comparative Example 4
Graphite (UF-G5 manufactured by Showa Denko K.K.) was added to a styrene-butadiene-styrene block copolymer (Tufprene A manufactured by Asahi Kasei Chemicals Corporation) in an amount of 4 mass% based on 100 mass% of the total amount of the composition, and the mixture was kneaded in a twin-screw kneader (KZW15TW-30MG-NH manufactured by Technovel Corporation, diameter 15 mm, L/D=30). The obtained pellets were kneaded under the following conditions:
Equipment used: TA Instruments Q20
Measurement holding temperature 170℃
Heating rate: 99.9°C/min. Atmosphere: _N2 (50 mL/min).
_O2 (switched on 5 minutes after reaching the holding temperature)
The oxidation induction time was measured by the following method.

As a result, the oxidation induction time was 12.3 minutes.

In this way, by kneading a composite of flaky carbon and specific organic matter into the resin, it was possible to slow down oxidation.

In Examples 1 to 7, despite the addition of large amounts of 3 to 7.5 mass% of the flaky carbon of the present invention, i.e., a durability improver containing a carbon component, the oxidation induction time was longer and the antioxidant properties were improved compared to Comparative Examples 1 and 3. On the other hand, when additives such as carbon nanofibers or graphite, which are carbon components, were added as in Comparative Examples 2 and 4, the oxidation induction time was shorter and the antioxidant properties were worse compared to Comparative Examples 1 and 3. Considering that the addition of additives usually reduces durability, the improved durability in Examples 1 to 7 despite the addition of large amounts of carbon components is an unexpected result.

Claims (11)

The present invention relates to a method for producing a carbon fiber composite, and a method for producing the same.
the hydrophilic group is a phenolic hydroxyl group and/or a polyoxyethylene group,
The hydrophobic group is an aryl group having two or more aromatic rings .
An agent that improves the oxidation resistance of resins . The oxidation resistance improver for resin according to claim 1, wherein the thickness of the flaky carbon is 1 to 100 nm. 3. The oxidation resistance improver for resins according to claim 1, wherein the organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon is a polyphenol. The oxidation resistance improver for a resin according to any one of claims 1 to 3, containing 1 to 1000 parts by mass of an organic compound having a hydrophilic group and a hydrophobic group having high affinity with carbon, relative to 100 parts by mass of the flaky carbon. The resin oxidation resistance improver according to any one of claims 1 to 4, which is an antioxidant . A method for producing the oxidation resistance improver for resin according to any one of claims 1 to 5, comprising:
(1) A production method comprising a step of removing a solvent from a dispersion containing the flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon, and a solvent. The manufacturing method described in claim 6, wherein the step of removing the solvent is a step of concentrating the dispersion. The manufacturing method described in claim 6 or 7, wherein the solvent is water. A resin composition having improved oxidation resistance , comprising the agent for improving the oxidation resistance of resin according to any one of claims 1 to 5 and a resin. 10. The resin composition with improved oxidation resistance according to claim 9, wherein the resin is an aromatic polymer compound . A method for producing the resin composition having improved oxidation resistance according to claim 9 or 10,
(2) A manufacturing method comprising a step of kneading the resin with the agent for improving the oxidation resistance of the resin .