JP2012162587A - Resin composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composite material that contains fine graphite particles and has high stiffness and high electric conductivity.SOLUTION: The resin composite material contains: the fine graphite particles, each of which comprises a plate-like graphite particle, an aromatic vinyl copolymer that is adsorbed on the plate-like graphite particle and contains a vinyl aromatic monomer unit that is represented by formula (1):-(CH-CHX)- (In the formula (1), X represents a phenyl group, a naphthyl group, an anthracenyl group or a pyrenyl group, which may have a substituent.); and at least one aromatic polymer selected from a group comprising a polystylene and polyphenylene ether.

Description

  The present invention relates to a resin composite material containing graphite particles.

  Conventionally, various fillers have been added to resins to impart the properties of the filler to the resins. For example, adding rigidity such as adding glass fiber or carbon fiber, or adding metal filler such as copper or aluminum, carbon filler such as graphite, carbon black, carbon nanotube, etc. to give electrical conductivity. (For example, JP 59-96142 A (Patent Document 1), JP 2007-5547 A (Patent Document 2), JP 2010-155993 A (Patent Document 3)).

  However, as described in Patent Documents 1 to 3, when the glass fiber, carbon fiber, metal filler, and carbon filler are mixed with the resin as they are, the properties of these fillers are sufficiently imparted to the resin. I could not say. In particular, graphite particles are easy to aggregate and have low affinity with the resin, and are dispersed in the resin in an aggregated state. Therefore, the aggregated particles have heat resistance, chemical resistance, mechanical strength, heat It has been difficult to fully develop the characteristics of graphite particles such as conductivity and conductivity.

  Thus, various methods for highly dispersing graphite particles in the resin have been proposed. For example, the surface of a carbon filler such as graphite is modified by modification with a carboxylic acid ester, and this is added to a polymer (for example, JP 2002-508422 A (Patent Document 4)). A method of melting and kneading the calated graphite oxide with a thermoplastic resin (Japanese Patent Laid-Open No. 2006-233017 (Patent Document 5)) is disclosed. Further, although not graphite particles, as a method of highly dispersing nanocarbon, a method of adding a nanocarbon composite whose surface is coated with a polyimide resin or the like (Japanese Patent Laid-Open No. 2006-144201 (Patent Document 6)), A method of dispersing hydrogenated or alkylated layered carbon in a resin (Japanese Patent Laid-Open No. 2003-268245 (Patent Document 7)) is also disclosed.

  However, when the surface modification treatment is performed on the carbon material as described above, the characteristics (particularly, electrical conductivity) of the carbon material tend to be impaired, and the carbon material is highly dispersed in the resin, but the characteristics are sufficiently high. There was still room for improvement in the methods described in Patent Documents 4 to 7 without being given.

JP 59-96142 A JP 2007-5547 A JP 2010-155993 A Special table 2002-508422 gazette JP 2006-233017 A JP 2006-144201 A JP 2003-268245 A

  This invention is made | formed in view of the subject which the said prior art has, and it aims at providing the resin composite material which contains graphite particle | grains and has high rigidity and high electrical conductivity.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a refined graphite obtained by mixing and pulverizing graphite particles, a specific aromatic vinyl copolymer, and a hydrogen peroxide. To add the particles to polystyrene, polyphenylene ether, or a mixture thereof, it is found that high rigidity and high electrical conductivity are imparted to polystyrene, polyphenylene ether, or a mixture thereof, and the present invention is completed. It came.

That is, the resin composite material of the present invention has plate-like graphite particles and the following formula (1) adsorbed on the plate-like graphite particles:
_{- (CH 2 -CHX) - (} 1)
(In formula (1), X represents a phenyl group, a naphthyl group, an anthracenyl group, or a pyrenyl group, and these groups may have a substituent.)
A fine graphite particle comprising an aromatic vinyl copolymer containing a vinyl aromatic monomer unit represented by the formula: and at least one aromatic polymer selected from the group consisting of polystyrene and polyphenylene ether It is characterized by this.

  In such a resin composite material, the content of the fine graphite particles is preferably 0.1 to 80% by mass. The aromatic polymer is preferably a mixture of polystyrene and polyphenylene ether. In this case, the polystyrene content in the mixture is preferably 20 to 80% by mass.

  In the resin composite material of the present invention, the aromatic vinyl copolymer preferably includes the vinyl aromatic monomer unit and the polar monomer unit, and the polar monomer unit includes (meth) acrylic acid, Monomer units derived from at least one monomer selected from the group consisting of (meth) acrylates, (meth) acrylamides, vinylpyridines, maleic anhydride, maleimides and vinylimidazoles are preferred.

The resin composite material of the present invention preferably has a storage elastic modulus at 40 ° C. of 2 GPa or more, and preferably has an electric resistance per unit length of 10 ⁴ Ω / cm or less.

  In addition, the reason why high rigidity and high electrical conductivity are imparted to at least one aromatic polymer selected from the group consisting of polystyrene and polyphenylene ether by the refined graphite particles according to the present invention is not necessarily clear. However, the present inventors infer as follows. That is, in the refined graphite particles according to the present invention, since the aromatic vinyl copolymer is adsorbed on the surface of the refined plate-like graphite particles, the cohesive force between the plate-like graphite particles is reduced. In addition, since the vinyl aromatic monomer unit constituting the aromatic vinyl copolymer is excellent in affinity with the aromatic polymer (especially polystyrene), the fine graphite particles have the aromatic polymer ( In particular, it is presumed to be well dispersed in polystyrene. Furthermore, since the said vinyl aromatic monomer unit has the stable adsorptivity with respect to plate-like graphite particle | grains, it is estimated that the dispersion stability of refined | miniaturized graphite particle | grains also improves. Thus, in the resin composite material of this invention, since the said refined graphite particle is highly disperse | distributing in the said aromatic polymer, it is guessed that high rigidity and high electrical conductivity are shown.

  The reason why the rigidity and electrical conductivity are further improved by using a mixture of polystyrene and polyphenylene ether as the aromatic polymer according to the present invention is not necessarily clear, but the present inventors have as follows. I guess. That is, the fine graphite particles according to the present invention exhibit high dispersibility with respect to polystyrene, but dispersibility with respect to polyphenylene ether tends to be lower than that of polystyrene. For this reason, when polystyrene and polyphenylene ether are mixed and the proportion of polyphenylene ether increases, the dispersibility of the fine graphite particles in the mixture decreases, and some fine graphite particles exist in contact with each other. Inferred. As described above, when a part of the fine graphite particles in the resin composite material comes into contact with each other, the particles are connected to form a network structure, and an electric conduction path is formed in the resin composite material. It is presumed that high electrical conductivity is exhibited as compared with a state in which fine graphite particles are completely dispersed or agglomerated. In addition, even when the resin composite material is mechanically deformed, the network structure effectively reinforces, so that it is assumed that the refined graphite particles exhibit high rigidity compared to the completely dispersed state or the aggregated state. Is done.

  According to the present invention, it is possible to obtain a resin composite material containing graphite particles and polystyrene, polyphenylene ether, or a mixture thereof and having high rigidity and high electrical conductivity.

It is a graph which shows the relationship between the temperature of the polystyrene resin composite material obtained in Examples 3-7 and the polystyrene resin material obtained in Comparative Example 2, and a storage elastic modulus. It is a graph which shows the relationship between the temperature of the polystyrene resin composite material obtained in Examples 3-7 and the polystyrene resin material obtained in Comparative Example 2, and a loss elastic modulus. It is a graph which shows the relationship between content of the fine graphite particle | grains in a polystyrene resin composite material, a storage elastic modulus, and an electrical resistance. It is a graph which shows the storage elastic modulus of the polystyrene resin composite material obtained in Example 2, and the polystyrene resin composite material obtained in Comparative Examples 5-8. 3 is a scanning electron micrograph showing a cross section of the polystyrene resin composite material obtained in Example 2. FIG. 6 is a scanning electron micrograph showing a cross section of the polystyrene resin composite material obtained in Comparative Example 3. FIG. It is a graph which shows the relationship between the temperature and storage elastic modulus of the polyphenylene ether resin composite material obtained in Examples 8-14 and the polyphenylene ether resin material obtained in Comparative Example 9. It is a graph which shows the relationship between the temperature and loss elastic modulus of the polyphenylene ether resin composite material obtained in Examples 8-14 and the polyphenylene ether resin material obtained in Comparative Example 9. It is a graph which shows the relationship between content of the refined graphite particle in a polyphenylene ether resin composite material, a storage elastic modulus, and an electrical resistance. It is a graph which shows the relationship between content of the refined graphite particle in a polystyrene-polyphenylene ether resin composite material, and a storage elastic modulus. It is a graph which shows the relationship between the polystyrene content in a polystyrene-polyphenylene ether resin composite material, and a storage elastic modulus. It is a graph which shows the relationship between the polystyrene content in a polystyrene-polyphenylene ether resin composite material, and an electrical resistance.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The resin composite material of the present invention is at least one selected from the group consisting of plate-like graphite particles and fine graphite particles comprising a specific aromatic vinyl copolymer adsorbed on the plate-like graphite particles, and polystyrene and polyphenylene ether. It contains a kind of aromatic polymer.

<Refined graphite particles>
First, the refined graphite particles according to the present invention will be described. The fine graphite particles according to the present invention comprise plate-like graphite particles and an aromatic vinyl copolymer adsorbed on the plate-like graphite particles.

  The plate-like graphite particles are not particularly limited. For example, known graphite having a graphite structure (artificial graphite, natural graphite (for example, flaky graphite, massive graphite, earthy graphite)) should not be destroyed. What is obtained by grind | pulverizing is mentioned.

  The thickness of such plate-like graphite particles is not particularly limited, but is preferably 0.3 to 1000 nm, more preferably 0.3 to 100 nm, and particularly preferably 1 to 100 nm. Further, the size in the planar direction of the plate-like graphite particles is not particularly limited. For example, the length in the major axis direction (major axis) is preferably 0.1 to 500 μm, more preferably 1 to 500 μm, and the minor axis. The length (minor axis) in the direction is preferably 0.1 to 500 μm, and more preferably 0.3 to 100 μm.

  Moreover, it is preferable that functional groups such as a hydroxyl group, a carboxyl group, and an epoxy group are bonded (preferably covalently bonded) to the surface of the plate-like graphite particles according to the present invention. The functional group has an affinity with the aromatic vinyl copolymer according to the present invention, and the adsorption amount and adsorption force of the aromatic vinyl copolymer to the plate-like graphite particles are increased, so that the fine graphite particles Tends to be highly dispersible in the aromatic polymer (especially polystyrene) according to the present invention.

  Such a functional group is 50% or less (more preferably 20% or less, particularly preferably 10% or less) of the total carbon atoms in the vicinity of the surface of the plate-like graphite particles (preferably, a region from the surface to a depth of 10 nm). It is preferable that it is bonded to the carbon atom. When the ratio of the carbon atom to which the functional group is bonded exceeds the upper limit, the plate-like graphite particles tend to have a low affinity with the aromatic vinyl copolymer because the hydrophilicity increases. Moreover, there is no restriction | limiting in particular as a minimum of the ratio of the carbon atom which the functional group has couple | bonded, However 0.01% or more is preferable. The functional group such as a hydroxyl group can be quantified by X-ray photoelectron spectroscopy (XPS), and the amount of the functional group present in a region from the particle surface to a depth of 10 nm can be measured. In addition, when the thickness of the plate-like graphite particles is 10 nm or less, the amount of functional groups present in the entire region of the plate-like graphite particles is measured.

The aromatic vinyl copolymer according to the present invention has the following formula (1):
_{- (CH 2 -CHX) - (} 1)
(In formula (1), X represents a phenyl group, a naphthyl group, an anthracenyl group, or a pyrenyl group, and these groups may have a substituent.)
The vinyl aromatic monomer unit represented by these and other monomer units are contained.

  In such an aromatic vinyl copolymer, the vinyl aromatic monomer unit exhibits an adsorptivity to graphite particles and a high affinity with the aromatic polymer (particularly polystyrene) according to the present invention. . When the other monomer unit is a polar monomer unit, the polar monomer unit exhibits affinity with the aromatic polymer according to the present invention (particularly polystyrene) and the functional group in the vicinity of the graphite particle surface. Therefore, such an aromatic vinyl copolymer is adsorbed on the plate-like graphite particles to reduce the cohesive force between the plate-like graphite particles, and at the same time, the aromatic polymer according to the present invention (particularly polystyrene). ), And the plate-like graphite particles can be highly dispersed in the aromatic polymer (particularly polystyrene) according to the present invention.

  In addition, as described above, since vinyl aromatic monomer units are easily adsorbed on graphite particles, a copolymer having a higher vinyl aromatic monomer unit content increases the amount of adsorption on plate-like graphite particles, resulting in finer structures. Graphite particles tend to be highly dispersible in the aromatic polymer (particularly polystyrene) according to the present invention. As content of a vinyl aromatic monomer unit, 10-98 mass% is preferable with respect to the whole aromatic vinyl copolymer, 30-98 mass% is more preferable, 50-95 mass% is especially preferable. When the content of the vinyl aromatic monomer unit is less than the lower limit, the amount of adsorption of the aromatic vinyl copolymer to the plate-like graphite particles tends to decrease, and the dispersibility of the fine graphite particles tends to decrease. When the content of the vinyl aromatic monomer unit exceeds the above upper limit, the affinity for the aromatic polymer (particularly polystyrene) according to the present invention is not imparted to the plate-like graphite particles, and the dispersibility of the fine graphite particles is reduced. It tends to decrease.

  Examples of the substituent that the group represented by X in the formula (1) may have include an alkoxy group (for example, a methoxy group), a carbonyl group, an amide group, an imide group, a carboxyl group, and a carboxylate group. In particular, from the viewpoint of improving the dispersibility of the fine graphite particles, an alkoxy group such as a methoxy group is preferable, and a methoxy group is more preferable.

  Examples of such vinyl aromatic monomer units include styrene monomer units, vinyl naphthalene monomer units, vinyl anthracene monomer units, vinyl pyrene monomer units, vinyl anisole monomer units, vinyl benzoate ester monomer units, and acetyl styrene monomer units. Among them, from the viewpoint of improving the dispersibility of the fine graphite particles, a styrene monomer unit, a vinyl naphthalene monomer unit, and a vinyl anisole monomer unit are preferable.

  Although there is no restriction | limiting in particular as another monomer unit which comprises the aromatic vinyl copolymer concerning this invention, Affinity with the functional group of the aromatic polymer (especially polystyrene) concerning this invention and the graphite particle surface vicinity From the viewpoint of showing, a polar monomer unit is preferable, and among them, (meth) acrylic acid, (meth) acrylates, (meth) acrylamides, vinylimidazoles, vinylpyridines, maleic anhydride and maleimides More preferred are monomer units derived from at least one monomer selected. By using such an aromatic vinyl copolymer containing a polar monomer unit, the fine graphite particles have improved affinity with the aromatic polymer (especially polystyrene) according to the present invention, and the aromatic according to the present invention. It becomes possible to highly disperse in a group polymer (particularly polystyrene).

  Examples of the (meth) acrylates include alkyl (meth) acrylate, substituted alkyl (meth) acrylate (for example, hydroxyalkyl (meth) acrylate such as hydroxyethyl (meth) acrylate, and aminoalkyl such as dimethylaminoethyl (meth) acrylate). (Meth) acrylate) and the like. Examples of the (meth) acrylamides include (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide (for example, N, N-dimethyl (meth) acrylamide) and the like.

  Examples of the vinylimidazoles include 1-vinylimidazole. Examples of the vinyl pyridines include 2-vinyl pyridine and 4-vinyl pyridine. Examples of the maleimides include maleimide, alkylmaleimide (eg, methylmaleimide, ethylmaleimide), arylmaleimide (eg, phenylmaleimide), and the like.

  Among such polar monomers, alkyl (meth) acrylate, hydroxyalkyl (meth) acrylate, aminoalkyl (meth) acrylate, and N, N-dialkyl (meth) from the viewpoint of improving the dispersibility of the fine graphite particles. Acrylamide, 2-vinylpyridine, 4-vinylpyridine and arylmaleimide are preferred, hydroxyalkyl (meth) acrylate, N, N-dialkyl (meth) acrylamide, 2-vinylpyridine and arylmaleimide are more preferred, and phenylmaleimide is particularly preferred. .

  In the fine graphite particles according to the present invention, the number average molecular weight of the aromatic vinyl copolymer is not particularly limited, but is preferably 1,000 to 1,000,000, and more preferably 5,000 to 100,000. If the number average molecular weight of the aromatic vinyl copolymer is less than the lower limit, the adsorptive capacity to graphite particles tends to be reduced. On the other hand, if the upper limit is exceeded, the solubility in a solvent is reduced or the viscosity is remarkably increased. It tends to rise and become difficult to handle. The number average molecular weight of the aromatic vinyl copolymer was measured by gel permeation chromatography (column: Shodex GPC K-805L and Shodex GPC K-800RL (both manufactured by Showa Denko KK), eluent: chloroform). It is a value converted with standard polystyrene.

  In the refined graphite particles according to the present invention, a random copolymer or a block copolymer may be used as the aromatic vinyl copolymer, but the dispersibility of the refined graphite particles is improved. From the viewpoint of achieving this, it is preferable to use a block copolymer.

In fine graphite particles according to the present invention, the content of the aromatic vinyl copolymer, preferably ¹⁰ -7 ^{to 10 -1} parts by weight with respect to the plate-like graphite particles 100 parts by weight, ^{10 -5 10-2} mass parts is more preferable. When the content of the aromatic vinyl copolymer is less than the lower limit, because the adsorption of the aromatic vinyl copolymer to the plate-like graphite particles is insufficient, the dispersibility of the fine graphite particles tends to decrease, On the other hand, when the upper limit is exceeded, there is a tendency that an aromatic vinyl copolymer that is not directly adsorbed on the plate-like graphite particles exists.

  As described above, the fine graphite particles according to the present invention have a high affinity with the aromatic polymer (especially polystyrene) according to the present invention. In the resin composite material according to the present invention, the aromatic polymer ( In particular, it is highly dispersible in polystyrene), and is further excellent in dispersibility in a solvent. For example, as described later, the aromatic polymer and fine graphite particles according to the present invention are used as a solvent. In the case of producing the resin composite material of the present invention by mixing in, it is possible to easily and highly disperse the fine graphite particles in the solvent, and the fine graphite particles are contained in the aromatic polymer. The resin composite material of the present invention uniformly dispersed can be easily obtained.

  Next, the manufacturing method of the refined graphite particle concerning this invention is demonstrated. Fine graphite particles according to the present invention are obtained by mixing raw material graphite particles, an aromatic vinyl copolymer containing a vinyl aromatic monomer unit represented by the above formula (1), a hydrogen peroxide, and a solvent, It can manufacture by removing a solvent, after giving the grinding | pulverization process to the obtained mixture.

  As the graphite particles used as raw materials when producing the fine graphite particles according to the present invention (hereinafter referred to as “raw graphite particles”), known graphites having a graphite structure (artificial graphite, natural graphite (for example, scaly) Graphite, lump graphite, earthy graphite)), and among them, those that become plate-like graphite particles having a thickness in the above range by pulverization are preferable. Although there is no restriction | limiting in particular as a particle diameter of such a raw material graphite particle, 0.01-5 mm is preferable and 0.1-1 mm is more preferable.

  Moreover, it is preferable that functional groups such as a hydroxyl group, a carboxyl group, and an epoxy group are bonded (preferably covalently bonded) to the surface of the plate-like graphite particles constituting the raw graphite particles. The functional group has an affinity for the aromatic vinyl copolymer, the amount of adsorption of the aromatic vinyl copolymer on the plate-like graphite particles and the adsorptive power increase, and the resulting fine graphite particles are The dispersibility in the aromatic polymer (particularly polystyrene) according to the present invention tends to be high.

  Such a functional group is 50% or less (more preferably 20% or less, particularly preferably 10% or less) of the total carbon atoms in the vicinity of the surface of the plate-like graphite particles (preferably, a region from the surface to a depth of 10 nm). It is preferable that it is bonded to the carbon atom. When the ratio of the carbon atom to which the functional group is bonded exceeds the upper limit, the plate-like graphite particles tend to have a low affinity with the aromatic vinyl copolymer because the hydrophilicity increases. Moreover, there is no restriction | limiting in particular as a minimum of the ratio of the carbon atom which the functional group has couple | bonded, However 0.01% or more is preferable.

  As the hydrogen peroxide used in producing the fine graphite particles according to the present invention, a compound having a carbonyl group (for example, urea, carboxylic acid (benzoic acid, salicylic acid, etc.), ketone (acetone, methyl ethyl ketone, etc.), Complexes of carboxylic acid esters (methyl benzoate, ethyl salicylate, etc.) and hydrogen peroxide; compounds in which hydrogen peroxide is coordinated to compounds such as quaternary ammonium salts, potassium fluoride, rubidium carbonate, phosphoric acid, uric acid, etc. Is mentioned. Such hydrogen peroxide acts as an oxidant when producing fine graphite particles according to the present invention, and facilitates exfoliation between carbon layers without destroying the graphite structure of the raw graphite particles. is there. That is, hydrogen peroxide enters between the carbon layers to oxidize the surface of the layer, and proceeds with cleavage. At the same time, the aromatic vinyl copolymer penetrates into the cleaved carbon layer and stabilizes the cleavage surface. Promoted. As a result, the aromatic vinyl copolymer is adsorbed on the surface of the plate-like graphite particles, and the fine graphite particles can be highly dispersed in the aromatic polymer (especially polystyrene) according to the present invention. Become.

  Although there is no restriction | limiting in particular as a solvent used when manufacturing the refined graphite particle concerning this invention, Dimethylformamide (DMF), chloroform, a dichloromethane, chlorobenzene, dichlorobenzene, N-methylpyrrolidone (NMP), toluene, dioxane , Propanol, γ-picoline, acetonitrile, dimethyl sulfoxide (DMSO), dimethylacetamide (DMAC) are preferable, and dimethylformamide (DMF), chloroform, dichloromethane, chlorobenzene, dichlorobenzene, N-methylpyrrolidone (NMP), and toluene are more preferable. .

  When producing the refined graphite particles according to the present invention, first, the raw graphite particles, the aromatic vinyl copolymer, the hydrogenated product, and the solvent are mixed. The mixing amount of the raw graphite particles is preferably 0.1 to 500 g / L, more preferably 10 to 200 g / L, per liter of the solvent. When the mixing amount of the raw material graphite particles is less than the lower limit, the consumption of the solvent tends to increase, which tends to be economically disadvantageous. On the other hand, when the upper limit is exceeded, the viscosity of the liquid increases and handling becomes difficult. There is a tendency.

  Moreover, as a mixing amount of the said aromatic vinyl copolymer, 0.1-1000 mass parts is preferable with respect to 100 mass parts of said raw material graphite particles, and 0.1-200 mass parts is more preferable. When the mixing amount of the aromatic vinyl copolymer is less than the lower limit, the dispersibility of the resulting fine graphite particles tends to be reduced. On the other hand, when the upper limit is exceeded, the aromatic vinyl copolymer is dissolved in the solvent. In addition, the viscosity of the liquid increases and handling tends to be difficult.

  Further, the mixing amount of the hydrogen peroxide is preferably 0.1 to 500 parts by mass, more preferably 1 to 100 parts by mass with respect to 100 parts by mass of the raw graphite particles. When the mixing amount of the hydrogen peroxide is less than the lower limit, the dispersibility of the obtained fine graphite particles tends to be lowered. On the other hand, when the upper limit is exceeded, the raw graphite particles are excessively oxidized and obtained. There is a tendency for the conductivity of the fine graphite particles to decrease.

  Next, the obtained mixture is pulverized to pulverize the raw graphite particles into plate-like graphite particles. Since the aromatic vinyl copolymer is adsorbed on the surface of the plate-like graphite particles produced thereby, the resulting fine graphite particles are dispersed stably in the aromatic polymer (especially polystyrene) according to the present invention. Improves.

  Examples of the pulverization treatment according to the present invention include ultrasonic treatment (oscillation frequency is preferably 15 to 400 kHz, output is preferably 500 W or less), treatment with a ball mill, wet pulverization, explosion, mechanical pulverization, and the like. This makes it possible to obtain plate-like graphite particles by pulverizing the raw graphite particles without destroying the graphite structure of the raw graphite particles. Moreover, there is no restriction | limiting in particular as temperature at the time of a grinding | pulverization process, For example, -20-100 degreeC is mentioned. Moreover, there is no restriction | limiting in particular also about pulverization processing time, For example, 0.01 to 50 hours are mentioned.

  Since the fine graphite particles thus obtained are dispersed in a solvent, the fine graphite particles can be recovered by removing the solvent by filtration or centrifugation.

<Aromatic polymer>
Next, the aromatic polymer according to the present invention will be described. The aromatic polymer according to the present invention is at least one polymer selected from the group consisting of polystyrene and polyphenylene ether.

  Examples of the polystyrene include a styrene homopolymer; a styrene homopolymer having a substituent on an aromatic ring such as 4-methylstyrene, 4-hydroxystyrene, and 4-aminostyrene; and a substituent on styrene and the aromatic ring. Examples thereof include a copolymer with styrene. Examples of the polyphenylene ether include polyphenylene having a substituent such as an alkyl group on an aromatic ring typified by poly (1,4-phenylene oxide) and poly (2,6-dimethyl-1,4-phenylene oxide). And oxides.

  The number average molecular weight of such an aromatic polymer such as polystyrene or polyphenylene ether is not particularly limited, but is preferably 1,000 to 1,000,000, more preferably 10,000 to 1,000,000. When the number average molecular weight of the aromatic polymer is less than the lower limit, the mechanical strength of the resin composite material tends to decrease. On the other hand, when the upper limit is exceeded, the viscosity becomes too high and the resin composite material is molded. Tend to be difficult. The number average molecular weight of the aromatic polymer according to the present invention is determined by gel permeation chromatography (column: Shodex GPC K-805L and Shodex GPC K-800RL (both manufactured by Showa Denko KK), eluent: chloroform). It is a value measured by the above and converted with standard polystyrene.

<Resin composite material>
The resin composite material of the present invention contains the fine graphite particles and at least one aromatic polymer selected from the group consisting of polystyrene and polyphenylene ether. Thus, by including the refined graphite particles according to the present invention, it is possible to impart high rigidity and high electrical conductivity to the aromatic polymer while maintaining high heat resistance.

  In such a resin composite material, the content of the fine graphite particles is not particularly limited, but is preferably 0.1 to 80% by mass and more preferably 1 to 50% by mass with respect to the entire resin composite material. 1 to 30% by mass is particularly preferable. If the content of the fine graphite particles is less than the lower limit, the rigidity and electrical conductivity of the resin composite material tend to decrease. On the other hand, if the content exceeds the upper limit, it is difficult to mold the resin composite material. It is in. In addition, by increasing the content of the fine graphite particles within the above range, the storage elastic modulus can be increased and the electric resistance can be reduced. When it exceeds%, it tends to show a substantially constant value.

  Moreover, in the resin composite material of the present invention, as the aromatic polymer, it is possible to use only one of polystyrene and polyphenylene ether, but from the viewpoint of higher rigidity and electrical conductivity, Preference is given to using a mixture of polystyrene and polyphenylene ether. Further, since polystyrene and polyphenylene ether are completely compatible, the use of such a mixture tends to improve the heat resistance of the resin composite material. In such a mixture, the polystyrene content is not particularly limited, but is preferably 20 to 80% by mass, and preferably 30 to 70% by mass with respect to the entire mixture, from the viewpoint of further increasing rigidity and electrical conductivity. Is more preferable.

Thus, in the resin composite material of the present invention, high rigidity and high electrical conductivity can be achieved by adjusting the content of fine graphite particles and the mixing ratio of polystyrene and polyphenylene ether. As a result, in the resin composite material of the present invention, the storage elastic modulus at 40 ° C. can be preferably 2 GPa or more, more preferably 5 GPa or more, and particularly preferably 10 GPa or more. Further, the electrical resistance per unit length of the surface can be preferably 10 ⁴ Ω / cm or less, more preferably 10 ³ Ω / cm or less, and particularly preferably 10 ² Ω / cm or less.

  Such a resin composite material of the present invention can be produced, for example, by mixing the aromatic polymer according to the present invention and fine graphite particles at a predetermined ratio. At this time, it is preferable to use a solvent. There is no restriction | limiting in particular as said solvent, What was illustrated as a solvent used when manufacturing the refined graphite particle concerning this invention can be used.

  When the aromatic polymer and the fine graphite particles are mixed in a solvent, the aromatic polymer dissolves in the solvent and becomes uniform, and the fine graphite particles are also highly dispersed in the solvent. It becomes easy to mix with each other, and an advanced and uniform dispersion can be easily obtained. Moreover, the uniformity tends to be further improved by subjecting the obtained dispersion to ultrasonic treatment. And the resin composite material of this invention in which the fine graphite particle | grains were disperse | distributed highly in the said aromatic polymer can be obtained by removing a solvent from the dispersion liquid obtained in this way.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Preparation Example 1)
36 g of styrene (ST), 4 g of N-phenylmaleimide (PM), 100 mg of azobisisobutyronitrile, and 50 ml of toluene were mixed, and a polymerization reaction was performed at 85 ° C. for 10 hours in a nitrogen atmosphere. After allowing to cool, the mixture was purified by reprecipitation using chloroform-hexane to obtain 27 g of ST-PM (90:10) random copolymer. The number average molecular weight (Mn) of this ST-PM (90:10) random copolymer was determined by gel permeation chromatography (column: Shodex GPC K-805L and Shodex GPC K-800RL (both manufactured by Showa Denko KK). , Eluent: chloroform) and converted to standard polystyrene, it was 5.3 × 10 ⁴ .

  12.5 g of graphite particles (“EXP-P” manufactured by Nippon Graphite Industry Co., Ltd., particle diameter of 1 mm or less), 12.5 g of urea-hydrogen peroxide inclusion complex, ST-PM (90:10) random copolymer 1.25 g and 500 ml of N, N-dimethylformamide (DMF) were mixed and subjected to ultrasonic treatment (output: 250 W) for 5 hours at room temperature to obtain a graphite particle dispersion. The graphite particle dispersion was filtered to remove DMF, and the filter cake was vacuum dried to obtain fine graphite particles (G1).

Example 1
900 mg of polystyrene (PS, manufactured by Aldrich, number average molecular weight 1 × 10 ⁵ ) and 100 mg of fine graphite particles (G1) obtained in Preparation Example 1 are added to 10 ml of chloroform, and the polystyrene is dissolved and refined by stirring. Graphite particles were dispersed, and the obtained dispersion was subjected to ultrasonic treatment (output: 250 W) for 30 minutes at room temperature. Next, 10 ml of the dispersion was cast into a petri dish having a diameter of 10 cm, and chloroform was removed to obtain a PS-G1 resin composite material. This PS-G1 resin composite material was subjected to press treatment at 150 ° C. and 5 MPa for 1 minute using a hot press. A series of these operations (cast-press) was repeated 5 times to obtain a PS-G1 (90:10) resin composite material in which fine graphite particles were uniformly dispersed in an aromatic polymer.

(Example 2)
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 800 mg and the amount of fine graphite particles (G1) is changed to 200 mg. -G1 (80:20) resin composite material was obtained.

(Example 3)
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 600 mg and the amount of fine graphite particles (G1) is changed to 400 mg. -G1 (60:40) resin composite material was obtained.

Example 4
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 500 mg and the amount of fine graphite particles (G1) is changed to 500 mg. -G1 (50:50) resin composite material was obtained.

(Example 5)
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 400 mg and the amount of fine graphite particles (G1) is changed to 600 mg. -G1 (40:60) resin composite material was obtained.

(Example 6)
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 300 mg and the amount of fine graphite particles (G1) is changed to 700 mg. -G1 (30:70) resin composite material was obtained.

(Example 7)
PS in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 1 except that the amount of polystyrene (PS) is changed to 200 mg and the amount of fine graphite particles (G1) is changed to 800 mg. -G1 (20:80) resin composite material was obtained.

(Comparative Example 1)
1000 mg of the refined graphite particles (G1) obtained in Preparation Example 1 is added to 10 ml of chloroform, and the refined graphite particles are dispersed by stirring. The obtained dispersion is subjected to ultrasonic treatment (output: 250 W) at room temperature for 30 minutes. ). Next, 10 ml of the dispersion was cast into a petri dish having a diameter of 10 cm, and chloroform was removed to obtain fine graphite particles. The fine graphite particles were subjected to press treatment at 150 ° C. and 5 MPa for 1 minute using a hot press. A series of these operations (cast-press) was repeated 5 times to obtain a G1 graphite particle material.

(Comparative Example 2)
1000 mg of polystyrene (PS, manufactured by Aldrich, number average molecular weight 1 × 10 ⁵ ) is added to 10 ml of chloroform, polystyrene is dissolved by stirring, and the resulting solution is subjected to ultrasonic treatment (output: 250 W) for 30 minutes at room temperature. gave. Next, 10 ml of the solution was cast into a petri dish having a diameter of 10 cm, and chloroform was removed to obtain polystyrene. This polystyrene was subjected to a press treatment of 5 MPa at 150 ° C. for 1 minute using a hot press. A series of operations (cast-press) was repeated 5 times to obtain a PS resin material.

(Comparative Example 3)
PS-EXP was performed in the same manner as in Example 2 except that 200 mg of graphite particles (“EXP-P” manufactured by Nippon Graphite Industry Co., Ltd., particle diameter of 1 mm or less) was used instead of the fine graphite particles (G1). -P (80:20) resin composite material was obtained.

(Comparative Example 4)
PS-UP- in the same manner as in Example 2 except that 200 mg of graphite particles ("UP-15N" manufactured by Nippon Graphite Industry Co., Ltd., particle size 15 μm) was used instead of the fine graphite particles (G1). A 15N (80:20) resin composite material was obtained.

(Comparative Example 5)
PS-MCF (80) in the same manner as in Example 2 except that 200 mg of carbon black (“MCF-1000” manufactured by Mitsubishi Chemical Corporation, particle diameter: 18 nm) was used instead of the fine graphite particles (G1). : 20) A resin composite material was obtained.

(Comparative Example 6)
Instead of the fine graphite particles (G1), carbon fiber (manufactured by Nippon Graphite Fiber Co., Ltd., trade name “Granock CF15M” (diameter 9.5 μm, length 200 μm), trade name “Granock CF03S” (diameter 9. 1 μm, length 400 μm), or trade name “Granock CF03Z” (diameter 10 μm, length 240 μm)) 200 mg was used in the same manner as in Example 2 except that PS-CF ( 80:20) A resin composite material was obtained.

(Comparative Example 7)
Instead of the fine graphite particles (G1), carbon nanotubes (manufactured by Showa Denko KK, trade name “VGCF” (outer diameter 150 nm, length 10-20 μm), trade name “VGCF-X” (outer diameter 10 ˜15 nm, length 3 μm), or trade name “VGCF-S” (outer diameter 100 nm, length 10 μm)) 200 mg was used in the same manner as in Example 2 except that each of the carbon nanotubes of each trade name was PS. A VGCF (80:20) resin composite material was obtained.

(Comparative Example 8)
Instead of the fine graphite particles (G1), glass fiber (manufactured by Central Glass Co., Ltd., trade name “ECS03-615” (diameter 9 μm, length 3 mm) or trade name “ECS03-631K” (diameter 13 μm, long) 3 mm)) PS-ECS (80:20) resin composite material was obtained in the same manner as in Example 2 except that 200 mg was used for the glass fibers of each trade name.

<Elastic modulus and electrical resistance>
The PS-G1 resin composite material prepared in Examples 1 to 7, the PS resin material prepared in Comparative Example 2, or the various resin composite materials prepared in Comparative Examples 3 to 8 are placed in a press die and pressed at 190 ° C. and 5 MPa. Molding was performed to obtain a test piece having a length of 30 mm, a width of 5 mm, and a thickness of 0.5 mm. On the other hand, the G1 graphite particle material prepared in Comparative Example 1 had no fluidity and it was difficult to produce a test piece.

  Using a viscoelastic spectrometer (“DVA-220” manufactured by IT Measurement Control Co., Ltd.), the elastic modulus of the obtained test piece was increased at 10 Hz while increasing the temperature from room temperature to 150 ° C. at 5 ° C./min. Measured with shaking. 1 and 2 show the measurement results of the storage elastic modulus and loss elastic modulus of the test pieces prepared from the PS-G1 resin composite materials of Examples 3 to 7 and the PS resin material of Comparative Example 2. Moreover, the storage elastic modulus in 40 degreeC about each test piece is shown to Tables 1-2 and FIGS. 3-4, and the loss elastic modulus in 40 degreeC is shown in Table 1. FIG. In addition, as a storage elastic modulus at the time of adding the carbon nanofiber (Comparative Example 6) shown in FIG. 4, the storage elastic modulus at 40 ° C. of the test piece for the carbon nanofiber of each trade name is obtained, respectively. The average value was shown. The same applies to carbon nanotubes (Comparative Example 7) and glass fibers (Comparative Example 8).

  The electrical resistance of the test piece was measured by bringing a probe of a tester (“CDM-09” manufactured by Custom Co., Ltd.) into contact with the surface of the test piece at a probe interval of 1 cm. The results are shown in Table 1 and FIG. FIG. 3 shows the electrical resistance measured for the G1 graphite particle material itself obtained in Comparative Example 1 without preparing a test piece, when the content of fine graphite particles is 100% by mass.

<Electron microscope observation>
The cross section of the test piece was observed with a scanning electron microscope (SEM). 5 to 6 show SEM photographs of cross sections of test pieces prepared from the PS-G1 resin composite material prepared in Example 2 and the PS-EXP-P resin composite material prepared in Comparative Example 3, respectively.

  As is apparent from the results shown in Table 1 and FIG. 3, the storage elastic modulus of the resin composite material is increased by the reinforcing effect by adding the fine graphite particles according to the present invention to polystyrene to make a composite. confirmed. Further, when the content of the fine graphite particles is 60% or less, the storage elastic modulus tends to increase as the content of the fine graphite particles increases, and on the other hand, when the content exceeds 60%, it becomes constant. I understood.

  Moreover, when the refined graphite particles according to the present invention are compounded by adding to polystyrene, the electrical resistance of the resin composite material is reduced, and the content of the refined graphite particles becomes 80% (Example 7). It turned out that it falls to the electric resistance (2 (ohm)) vicinity in the case of only the refined graphite particle (comparative example 1).

  As is apparent from the results shown in Table 2, when the refined graphite particles G1 according to the present invention are added (Example 2), the graphite particles that are the raw materials of the refined graphite particles are added as they are ( It was confirmed that the storage elastic modulus was higher than that of Comparative Examples 3 to 4). As is clear from the results shown in FIGS. 5 to 6, when the fine graphite particles according to the present invention are added (Example 2), the fine graphite particles are uniformly distributed in the resin composite material. When the graphite particles EXP-P, which is the raw material of the fine graphite particles, are added as they are while the plate-like graphite particles are dispersed and oriented parallel to the surface of the test piece (comparative example) In 3), the graphite particles are aggregated in the resin composite material and are in a non-uniform dispersion state, and the interfacial bonding force between polystyrene and graphite particles is weak and the orientation is irregular. It is done. In addition, when the graphite particles UP-15N were added as they were (Comparative Example 4), they were in the same dispersion state as in the case of the graphite particles EXP-P.

  In addition, when the refined graphite particles G1 according to the present invention were added (Example 2), the electrical resistance of the test piece was substantially constant at a plurality of measurement locations, whereas the refined graphite particles When the graphite particles as the raw material are added as they are (Comparative Examples 3 to 4), the electric resistance differs at each measurement location. For example, a portion showing insulation and a portion showing conductivity are seen on the same specimen surface. It was. As described above, this is considered to be due to the difference in the dispersibility of the graphite particles.

  As is apparent from the results shown in FIG. 4, when the fine graphite particles G1 according to the present invention were added (Example 2), carbon black (Comparative Example 5), carbon nanotube (Comparative Example 7), and glass The storage elastic modulus was higher than that when the fiber (Comparative Example 8) was added. On the other hand, when carbon fiber (Comparative Example 6) was added, the storage elastic modulus was the same as when the refined graphite particles G1 according to the present invention were added (Example 2). It was high and it was confirmed that the refined graphite particles according to the present invention are superior in cost.

(Example 8)
Implemented except that 900 mg of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE, Aldrich, number average molecular weight 5 × 10 ⁴ ) was used instead of polystyrene, and the press temperature was changed to 290 ° C. In the same manner as in Example 1, a PPE-G1 (90:10) resin composite material in which fine graphite particles were uniformly dispersed in an aromatic polymer was obtained.

Example 9
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 800 mg and the amount of fine graphite particles (G1) was changed to 200 mg, an aromatic was obtained. PPE-G1 (80:20) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Example 10)
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 600 mg and the amount of the fine graphite particles (G1) was changed to 400 mg, an aromatic was used. PPE-G1 (60:40) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Example 11)
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 500 mg and the amount of fine graphite particles (G1) was changed to 500 mg, the aromatic was changed. PPE-G1 (50:50) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Example 12)
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 400 mg and the amount of fine graphite particles (G1) was changed to 600 mg, aromatics were used. PPE-G1 (40:60) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Example 13)
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 300 mg and the amount of fine graphite particles (G1) was changed to 700 mg, the aromatic was changed. PPE-G1 (30:70) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Example 14)
In the same manner as in Example 8, except that the amount of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE) was changed to 200 mg and the amount of the fine graphite particles (G1) was changed to 800 mg, an aromatic was used. PPE-G1 (20:80) resin composite material in which fine graphite particles were uniformly dispersed in a polymer was obtained.

(Comparative Example 9)
Compared with 1000 mg of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE, Aldrich, number average molecular weight 5 × 10 ⁴ ) instead of polystyrene, except that the press temperature was changed to 290 ° C. In the same manner as in Example 2, a PPE resin material was obtained.

<Elastic modulus and electrical resistance>
The PPE-G1 resin composite material prepared in Examples 8 to 14 or the PPE resin material prepared in Comparative Example 9 is put into a press mold, press-molded at 300 ° C. and 5 MPa, length 30 mm, width 5 mm, thickness A test piece of 0.5 mm was obtained.

  Except that the measurement temperature range was changed from room temperature to 300 ° C., the elastic modulus of the obtained test piece was measured according to the method described in <Elastic modulus and electrical resistance>. In FIGS. 7-8, the measurement result of the storage elastic modulus and loss elastic modulus of the test piece produced from the PPE-G1 resin composite material of Examples 8-14 and the PPE resin material of the comparative example 9 is shown. Further, the storage elastic modulus at 40 ° C. for each test piece is shown in Table 3 and FIG. 9, and the loss elastic modulus at 40 ° C. is shown in Table 3.

  Further, the electrical resistance of the test piece was measured according to the method described in the above <elastic modulus and electrical resistance>. The results are shown in Table 3 and FIG. In addition, in FIG. 9, the electrical resistance measured about G1 graphite particle material itself obtained by the comparative example 1 without producing a test piece was shown as a case where content of refined graphite particle | grains is 100 mass%.

  As is clear from the results shown in Table 3 and FIG. 9, the storage elastic modulus of the resin composite material is increased by the reinforcing effect by adding the fine graphite particles according to the present invention to the polyphenylene ether to form a composite. Was confirmed. Further, when the content of the fine graphite particles is 60% or less, the storage elastic modulus tends to increase as the content of the fine graphite particles increases, and on the other hand, when the content exceeds 60%, it becomes constant. I understood.

  Moreover, when the refined graphite particles according to the present invention are added to polyphenylene ether to form a composite, the electrical resistance of the resin composite material is reduced, and the content of the refined graphite particles reaches 80% (Example 14). It was found that the electrical conductivity equivalent to the electrical resistance (2Ω) in the case of only the fine graphite particles (Comparative Example 1) was exhibited.

(Example 15)
300 mg of polystyrene (PS, manufactured by Aldrich, number average molecular weight 1 × 10 ⁵ ) and 700 mg of poly (2,6-dimethyl-1,4-phenylene oxide) (PPE, manufactured by Aldrich, number average molecular weight 5 × 10 ⁴ ) Were mixed and dissolved in 10 mg of chloroform, and the resulting solution was cast into a petri dish and dried at 25 ° C., followed by vacuum drying to obtain a PS30PPE70 resin composition.

  In the aromatic polymer in the same manner as in Example 1, except that 800 mg of the PS30PPE70 resin composition was used instead of polystyrene, the amount of fine graphite particles (G1) was changed to 200 mg, and the press temperature was changed to 290 ° C. A PS30PPE70-G1 (80:20) resin composite material in which fine graphite particles were uniformly dispersed was obtained.

(Example 16)
PS30PPE70 in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 15 except that the amount of the PS30PPE70 resin composition is changed to 600 mg and the amount of the fine graphite particles (G1) is changed to 400 mg. -G1 (60:40) resin composite material was obtained.

(Example 17)
PS30PPE70 in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 15 except that the amount of the PS30PPE70 resin composition is changed to 400 mg and the amount of the fine graphite particles (G1) is changed to 600 mg. -G1 (40:60) resin composite material was obtained.

(Example 18)
A PS50PPE50 resin composition was obtained in the same manner as in Example 15 except that the amount of polystyrene was changed to 500 mg and the amount of poly (2,6-dimethyl-1,4-phenylene oxide) was changed to 500 mg.

  PS50PPE50-G1 (80:20) resin composite in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 15 except that 800 mg of PS50PPE50 resin composition is used instead of the PS30PPE70 resin composition. Obtained material.

(Example 19)
PS50PPE50 in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 18 except that the amount of the PS50PPE50 resin composition is changed to 600 mg and the amount of the fine graphite particles (G1) is changed to 400 mg. -G1 (60:40) resin composite material was obtained.

(Example 20)
PS50PPE50 in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 18 except that the amount of the PS50PPE50 resin composition is changed to 400 mg and the amount of the fine graphite particles (G1) is changed to 600 mg. -G1 (40:60) resin composite material was obtained.

(Example 21)
A PS70PPE30 resin composition was obtained in the same manner as in Example 15 except that the amount of polystyrene was changed to 700 mg and the amount of poly (2,6-dimethyl-1,4-phenylene oxide) was changed to 300 mg.

  PS70PPE30-G1 (80:20) resin composite in which fine graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 15 except that 800 mg of PS70PPE30 resin composition was used instead of PS30PPE70 resin composition. Obtained material.

(Example 22)
PS70PPE30 in which finely divided graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 21 except that the amount of PS70PPE30 resin composition is changed to 600 mg and the amount of finely divided graphite particles (G1) is changed to 400 mg. -G1 (60:40) resin composite material was obtained.

(Example 22)
PS70PPE30 in which finely divided graphite particles are uniformly dispersed in an aromatic polymer in the same manner as in Example 21, except that the amount of PS70PPE30 resin composition is changed to 400 mg and the amount of finely divided graphite particles (G1) is changed to 600 mg. -G1 (40:60) resin composite material was obtained.

(Comparative Example 10)
A PS30PPE70 resin material was obtained in the same manner as in Comparative Example 2 except that 1000 mg of the PS30PPE70 resin composition prepared in the same manner as in Example 15 was used instead of polystyrene, and the press temperature was changed to 290 ° C.

(Comparative Example 11)
A PS50PPE50 resin material was obtained in the same manner as in Comparative Example 2 except that 1000 mg of PS50PPE50 resin composition prepared in the same manner as in Example 18 was used instead of polystyrene, and the press temperature was changed to 290 ° C.

(Comparative Example 12)
A PS70PPE30 resin material was obtained in the same manner as in Comparative Example 2 except that 1000 mg of PS70PPE30 resin composition prepared in the same manner as in Example 21 was used instead of polystyrene, and the press temperature was changed to 290 ° C.

<Elastic modulus and electrical resistance>
Various resin composite materials prepared in Examples 15 to 22 or various resin materials prepared in Comparative Examples 10 to 12 are placed in a press mold, press-molded at 300 ° C. and 5 MPa, length 30 mm, width 5 mm, thickness A test piece of 0.5 mm was obtained.

  Except that the measurement temperature range was changed from room temperature to 300 ° C., the elastic modulus of the obtained test piece was measured according to the method described in <Elastic modulus and electrical resistance>. The storage elastic modulus at 40 ° C. for each test piece is shown in Table 4 and FIGS. 10 to 11, and the loss elastic modulus at 40 ° C. is shown in Table 4. In addition, in FIG. 11, the storage elastic modulus about PS-G1 resin composite material of Example 2, 3, 5 and PS resin material of the comparative example 2, and PS content as a result of PS content being 100 mass%. The storage elastic modulus of the PPE-G1 resin composite materials of Examples 9, 10, and 12 and the PPE resin material of Comparative Example 9 was shown as a result of 0% by mass.

  Further, the electrical resistance of the test piece was measured according to the method described in the above <elastic modulus and electrical resistance>. The results are shown in Table 4 and FIG. In FIG. 12, as a result of the PS content of 100% by mass, the electrical resistance and PS content of the PS-G1 resin composite materials of Examples 2, 3, and 5 and the PS resin material of Comparative Example 2 are 0. The electric resistance about the PPE-G1 resin composite material of Example 9, 10, 12 and the PPE resin material of the comparative example 9 was shown as a result of the mass%.

  As apparent from the results shown in Table 4 and FIG. 10, any resin composition can be obtained by adding the fine graphite particles according to the present invention to a resin composition containing polystyrene and polyphenylene ether to form a composite. The storage elastic modulus of the resin composite material was confirmed to increase as the content of the fine graphite particles increased.

  Furthermore, as apparent from the results shown in Table 4 and FIG. 11, in the resin composite material of the present invention containing polystyrene and polyphenylene ether, when the content of the fine graphite particles is the same, polystyrene and polyphenylene ether. It was found that the storage elastic modulus reached a maximum value at a mass ratio of 50:50. Further, as is clear from the results shown in Table 4 and FIG. 12, it was found that the electrical resistance also had a minimum value when the mass ratio of polystyrene to polyphenylene ether was 50:50. The reason why such an extreme value exists is that, by blending two kinds of aromatic polymers, the dispersion structure of the fine graphite particles according to the present invention is changed as compared with the case of one kind, so that an appropriate interparticle distance is obtained. This is probably because the connection structure was formed.

  As described above, according to the present invention, a resin composite material having high rigidity and high electrical conductivity can be obtained.

  Therefore, the resin composite material of the present invention is used in applications requiring high rigidity and high electrical conductivity, for example, various parts for automobiles (for example, outer plate materials), various parts for electric / electronic devices (for example, electrode materials). It is useful as a heater material.

Claims (7)

Plate-like graphite particles and the following formula (1) adsorbed on the plate-like graphite particles:
_{- (CH 2 -CHX) - (} 1)
(In formula (1), X represents a phenyl group, a naphthyl group, an anthracenyl group, or a pyrenyl group, and these groups may have a substituent.)
A fine graphite particle comprising an aromatic vinyl copolymer containing a vinyl aromatic monomer unit represented by the formula: and at least one aromatic polymer selected from the group consisting of polystyrene and polyphenylene ether Resin composite material characterized by   The resin composite material according to claim 1, wherein a content of the fine graphite particles is 0.1 to 80% by mass. The aromatic polymer is a mixture of polystyrene and polyphenylene ether;
The resin composite material according to claim 1 or 2, wherein a polystyrene content in the mixture is 20 to 80% by mass.   The resin composite material according to any one of claims 1 to 3, wherein the aromatic vinyl copolymer includes the vinyl aromatic monomer unit and a polar monomer unit.   The polar monomer unit is at least one monomer selected from the group consisting of (meth) acrylic acid, (meth) acrylates, (meth) acrylamides, vinylpyridines, maleic anhydride, maleimides, and vinylimidazoles. The resin composite material according to claim 4, wherein the resin composite material is a monomer unit derived from   The resin composite material according to any one of claims 1 to 5, wherein a storage elastic modulus at 40 ° C is 2 GPa or more. 6. The resin composite material according to claim 1, wherein an electrical resistance per unit length of the surface is 10 ⁴ Ω / cm or less.