TW201638164A - Composite material production method and composite material - Google Patents

Abstract

The purpose of the present invention is to provide a composite material production method capable of efficiently producing a composite material having excellent physical properties. The composite material production method according to the present invention includes: a step for removing a solvent from a dispersion liquid in which a fibrous carbon material is dispersed in the solvent, and obtaining an easily dispersible aggregate of the fibrous carbon material; and a step for mixing the easily dispersible aggregate and a polymeric material, and obtaining a composite material containing the polymeric material and the fibrous carbon material.

Description

Composite material manufacturing method and composite material

The present invention relates to a method for producing a composite material and a composite material, and more particularly to a method for producing a composite material containing a fibrous carbon material and a composite material obtained by using the same.

Conventionally, as a material having excellent conductivity, thermal conductivity, and the like, a composite material obtained by blending a carbon material with a polymer material such as a resin or a rubber is used. Further, in recent years, fibrous carbon materials, particularly fibrous carbon nanostructures such as carbon nanotubes, have been attracting attention as carbon materials for efficiently improving conductivity and thermal conductivity.

Here, as a method of dispersing a fibrous carbon material such as a carbon nanotube in a matrix of a polymer material, there is a proposal to disclose a method of directly mixing the prepared fibrous carbon material with a polymer material; A method in which a dispersion of a fibrous carbon material dispersed in a solvent is mixed with a latex of a polymer material. Specifically, for example, Patent Document 1 proposes a method of producing a composite material by mixing a fibrous carbon material and a polymer material by using an open roll. Further, for example, Patent Document 2 proposes a method in which a dispersion obtained by dispersing a fibrous carbon material in a solvent by a dispersion treatment capable of obtaining a cavitation effect is mixed with a latex of a polymer material, and By solidifying the solid component in the obtained mixture in a weak solvent, A method of making a composite.

Prior technical literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-291230

[Patent Document 2] Japanese Patent No. 5263673

However, since the fibrous carbon material such as a carbon nanotube is easily aggregated and has low dispersibility, the method of directly mixing the fibrous carbon material and the polymer material using an open roll cannot sufficiently disperse the fibrous carbon material at a high level. In the matrix of molecular materials. Therefore, a composite material having excellent physical properties (for example, electrical conductivity, thermal conductivity, etc.) cannot be obtained by a method for producing a composite material of an open roll.

On the other hand, a method of solidifying a solid component in a mixture of a dispersion of a fibrous carbon material and a latex of a polymer material can be made by mixing a fibrous carbon material dispersed in a solvent with a polymer material. The carbon material is well dispersed in the matrix of the polymer material. However, in this method, since a large amount of solvent is used when the solid content in the mixture is solidified when the dispersion and the latex are adjusted, the amount of the solvent used is increased, and the production efficiency of the composite material cannot be sufficiently improved.

Accordingly, an object of the present invention is to provide a method for producing a composite material which can efficiently produce a composite material having excellent physical properties, and an object of the present invention is to provide a composite material produced by using the production method.

The inventors of the present invention conducted intensive discussions in order to achieve the above object. In addition, the inventors of the present invention have found that the dispersion of the fibrous carbon material obtained by dispersing the fibrous carbon material in a solvent (dispersion medium) removes the solvent, and the aggregate of the fibrous carbon material is highly dispersible. And when the easily dispersible aggregate of the fibrous carbon material obtained by removing the solvent from the dispersion is directly mixed with the polymer material, the fibrous carbon material can be well dispersed in the polymer without using a large amount of solvent. The present invention has been completed in the materials.

That is, the object of the present invention is to solve the above problems, and a method for producing a composite material according to the present invention includes the steps of removing the solvent from a dispersion obtained by dispersing a fibrous carbon material in a solvent. a step of obtaining an easily dispersible aggregate of a fibrous carbon material; and a step of mixing the easily dispersible aggregate with a polymer material to obtain a composite material comprising a polymer material and a fibrous carbon material. When the solvent (the dispersible aggregate) of the fibrous carbon material is removed from the dispersion of the fibrous carbon material and the polymer material is mixed, the fibrous carbon can be made without using a large amount of solvent. The material is well dispersed in the polymer material. Therefore, it is possible to efficiently manufacture a composite material having excellent physical properties.

Here, the method for producing a composite material of the present invention preferably further comprises the steps of: providing a coarse dispersion liquid obtained by adding a fibrous carbon material to a solvent to provide a cavitation effect or a pulverization effect. The step of obtaining the aforementioned dispersion is obtained. When a dispersion liquid obtained by dispersing a cavitation effect or a pulverization effect is provided for the coarse dispersion liquid, the dispersibility of the easily dispersible aggregate obtained by removing the solvent from the dispersion liquid can be further improved, and It is sufficient to disperse the fibrous carbon material more well in the polymer material. Therefore, the physical properties of the composite material can be further improved.

Further, in the method for producing a composite material of the present invention, it is preferred to carry out the removal of the solvent by filtration. The solvent can be removed more easily and quickly than by using an evaporator or the like to remove the solvent by filtration.

Further, in the method for producing a composite material of the present invention, the fibrous carbon material is preferably a fibrous carbon nanotube structure. When a fibrous carbon material containing a fibrous carbon nanostructure is used, the physical properties of the composite can be further improved. Further, in general, the fibrous carbon nanostructure is a material which is very easy to aggregate and has low dispersibility, but when the production method of the present invention is used, it can be well dispersed in a polymer material.

Further, the fibrous carbon nanostructure system described above preferably contains a carbon nanotube. When a fibrous carbon nanostructure containing a carbon nanotube is used, the physical properties of the composite can be further improved. Further, the fibrous carbon nanotube structure preferably has a BET specific surface area of 400 m ² /g or more. When a fibrous carbon nanostructure having a BET specific surface area of 400 m ² /g or more is used, the physical properties of the composite material can be further improved, and at the same time, excellent operation can be obtained when the solvent is removed from the dispersion liquid. Sexually dispersible aggregates.

Further, in the method for producing a composite material of the present invention, it is preferred that the polymerizable material is mixed with the easily dispersible aggregate in an amount of 0.01 part by mass or more and 10 parts by mass or less per 100 parts by mass of the polymer material. When the polymerizable material is mixed with the easily dispersible aggregate in a ratio of 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the polymer material, the fibrous carbon material can be sufficiently dispersed in the polymer material, and the obtained material can be obtained. The physical properties of the composite material are greatly enhanced.

Further, in the method for producing a composite material according to the present invention, it is preferable that the composite material further contains a particulate carbon material, and the easy-dispersibility aggregate, the polymer material, and the particulate carbon material are mixed to obtain the composite material. When the particulate carbon material is further contained, the physical properties of the composite material can be further improved.

Moreover, the object of the present invention is to solve the above problems, and the composite material of the present invention is produced by using any of the above-described methods for producing a composite material. When the above-described method for producing a composite material is used, a composite material having excellent physical properties can be obtained.

By using the method for producing a composite material of the present invention, a composite material having excellent physical properties can be efficiently produced.

Further, according to the present invention, a composite material having excellent physical properties can be obtained.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail.

The method for producing a composite material of the present invention can be used to produce a composite material containing a polymer material and a fibrous carbon material. Further, the composite material of the present invention produced by the method for producing a composite material of the present invention has excellent physical properties such as electrical conductivity and thermal conductivity.

(Manufacturing method of composite material)

Here, the method for producing a composite material of the present invention comprises the following steps: an easy dispersibility aggregate preparation step of dispersing a fibrous carbon material in a solvent a step of removing a solvent to obtain a dispersible aggregate of fibrous carbon material; and mixing the easily dispersible aggregate obtained by the easy dispersibility assembly preparation step with a polymer material, and The step of obtaining a composite material (composite preparation step). Further, in the method for producing a composite material according to the present invention, the easily dispersible aggregate obtained by removing the solvent from the dispersion of the fibrous carbon material is mixed with the polymer material to prepare a composite material, so that it is not necessary to use a large amount of solvent. The fibrous carbon material can be well dispersed in the polymer material. As a result, a composite material having excellent physical properties such as conductivity and thermal conductivity can be efficiently obtained.

(easy dispersibility aggregate modulation step)

In the easy dispersibility aggregate preparation step, a solvent (dispersion medium) is removed from a dispersion containing a plurality of fibrous carbon materials to obtain an easily dispersible aggregate in which a plurality of fibrous carbon materials are assembled. Further, since the easily dispersible aggregate obtained in the easy-dispersibility aggregate preparation step is composed of a fibrous carbon material obtained by dispersing it in a solvent at a time, it is compared with that before it is dispersed in a solvent. The aggregate of fibrous carbon materials has superior dispersibility.

<dispersion>

Here, the dispersion liquid used for preparation of the easily dispersible aggregate is not particularly limited, and a dispersion liquid in which a fibrous carbon material assembly is dispersed in a solvent can be used by a known dispersion treatment method. Specifically, as the dispersion liquid, a dispersion liquid containing an additive for a dispersion liquid such as a dispersant or the like, which contains a fibrous carbon material and a solvent, can be used.

[Fibrous carbon material]

Further, the fibrous carbon material is not particularly limited, and for example, A carbon fiber obtained by carbonizing a carbon nanotube, a vapor-grown carbon fiber, or an organic fiber, and the like, and the like. These may be used alone or in combination of two or more.

In particular, as the fibrous carbon material, a fibrous carbon nanotube structure such as a carbon nanotube is preferably used, and a fibrous carbon nanotube structure containing a carbon nanotube is preferably used. When a fibrous carbon nanostructure such as a carbon nanotube is used, the physical properties of the composite can be further improved.

[[Fiber carbon nanotube structure containing carbon nanotubes]]

Here, a fibrous carbon nanotube structure containing a carbon nanotube material as a fibrous carbon material can be suitably used, and it can be composed only of a carbon nanotube (hereinafter referred to as "CNT"). It is a mixture of fibrous carbon nanostructures other than CNT and CNT. Further, the CNT in the fibrous carbon nanostructure is not particularly limited, and a single-layer carbon nanotube and/or a multilayer carbon nanotube can be used, but the CNT is a nano layer from a single layer to a fifth layer. A carbon tube is preferred, and a single layer of carbon nanotubes is preferred. When a single-layer carbon nanotube is used, the physical properties of the composite can be further improved compared to the case of using a multi-layered carbon nanotube.

Further, the average diameter (Av) of the CNT-containing fibrous carbon nanotube structure is preferably 0.5 nm or more, more preferably 1 nm or more, still more preferably 15 nm or less, and still more preferably 10 nm or less. When the average diameter (Av) of the fibrous carbon nanostructure is 0.5 nm or more, the dispersibility of the fibrous carbon nanostructure in the polymer material can be further improved. Moreover, when the average diameter (Av) of the fibrous carbon nanostructure is 15 nm or less, the physical properties of the composite material can be further improved. In addition, the "average diameter (Av) of the fibrous carbon nanostructure" can be measured by a transmission electron microscope to measure the randomly selected fibrous carbon nanostructure. The diameter (outer diameter) of 100 pieces is obtained. Further, the average diameter (Av) of the CNT-containing fibrous carbon nanotube structure can be adjusted by changing the manufacturing method and manufacturing conditions of the CNT-containing fibrous carbon nanotube structure, or can be used differently. The fibrous carbon nanotube structure containing CNT obtained by the method of the method is adjusted by combining a plurality of types.

Further, a BET carbon nano structure of the fibrous surface area of the CNT-containing, based to 400m ² / g or more preferably to 800m ² / g or more is more preferred to 2500m ² / g or less preferably to 1200m ² / The following is better. When the BET specific surface area of the CNT-containing fibrous carbon nanotube structure is 400 m ² /g or more, the physical properties of the composite material can be further improved, and at the same time, the solvent can be excellently obtained when the solvent is removed from the dispersion liquid. An operationally easy to disperse aggregate. When the BET specific surface area of the CNT-containing fibrous carbon nanotube structure is 2,500 m ² /g or less, the dispersibility of the fibrous carbon nanotube structure in the polymer material can be further improved. Further, in the present invention, the "BET specific surface area" means a nitrogen adsorption specific surface area measured by the BET method.

In addition, the CNT-containing fibrous carbon nanostructure can be vertically vertical on the substrate having the catalyst layer for carbon nanotube growth on the surface by using the Super-Growth method described later. In the direction of the assembly of the matrix (alignment aggregate), the mass density of the fibrous carbon nanotube structure as the aggregate is preferably 0.002 g/cm ³ or more and 0.2 g/cm ³ or less. . When the mass density is 0.2 g/cm ³ or less, the connection between the fibrous carbon nanostructures is weakened, so that the fibrous carbon nanostructures can be uniformly dispersed. In addition, when the mass density is 0.002 g/cm ³ or more, the integration of the fibrous carbon nanotube structure can be improved and the scattering can be suppressed, so that the handling becomes easy.

Further, the CNT-containing fibrous carbon nanotube structure is preferably a shape in which a t-plot obtained from an adsorption isotherm exhibits an upward convex shape. In particular, it is preferable that the t-plot can display the upward convex shape without performing the opening treatment of the CNT. Moreover, "t-plot" can convert the relative pressure into the average thickness t (nm) of the nitrogen adsorption layer by the adsorption isotherm of the fibrous carbon nanostructure measured by the nitrogen gas adsorption method. get. That is, by plotting the relative pressure P/P0 against the average thickness t of the nitrogen adsorption layer, the average thickness t of the nitrogen adsorption layer corresponding to the relative pressure is obtained from a known standard isotherm and the above transformation is performed. A t-plot of a fibrous carbon nanotube structure containing CNTs was obtained (using the t-plot method of deBoer et al.).

Here, the substance having pores on the surface and the growth of the nitrogen adsorption layer are classified into the following processes (1) to (3). Further, the inclination of the t-plot changes depending on the processes of the following (1) to (3).

(1) Formation process of single molecule adsorption layer of nitrogen molecules on the whole surface

(2) Formation of multi-molecular adsorption layer and capillary condensation filling process accompanying it in pores

(3) The formation process of the multimolecular adsorption layer on the non-porous surface after the pores are filled with nitrogen

Further, the t-plot showing the upwardly convex shape, in a region where the average thickness t of the nitrogen adsorption layer is small, the plot is located on a straight line passing through the origin, and when t becomes large, the drawing is performed. (plot) is located at a position shifted downward from the straight line. The fibrous carbon nanostructure having the shape of such a t-plot indicates that the ratio of the internal specific surface area to the total specific surface area of the fibrous carbon nanostructure is large, and a plurality of openings are formed in the form of fibers. Carbon nanostructure Carbon nanostructure of the body.

Further, the bending point of the t-plot of the CNT-containing fibrous carbon nanotube structure is preferably in the range of 0.2 ≦t (nm) ≦ 1.5, and preferably in the range of 0.45 ≦ t (nm) ≦ 1.5. A range of 0.55 ≦ t (nm) ≦ 1.0 is more preferable. Further, the "position of the bending point" is the intersection of the approximate straight line A of the process of the above (1) and the approximate straight line B of the process of the above (3).

Further, in the CNT-containing fibrous carbon nanotube structure, the ratio (S2/S1) of the internal specific surface area S2 to the total specific surface area S1 obtained from t-plot is preferably 0.05 or more and 0.30 or less. Furthermore, the total specific surface area structure containing fibrous carbon nano CNT internal surface area S1 and S2, based not particularly limited, individually, lines S1 to 600m ² / g or more, 1400m ² / g or less preferably to 800m ² / g or more and 1200 m ² /g or less are more preferable. On the other hand, S2 based at 30m ² / g or more, 540m ² / g or less is preferable.

Here, the total specific surface area S1 and the internal specific surface area S2 of the CNT-containing fibrous carbon nanotube structure can be obtained from the t-plot. Specifically, first, the total specific surface area S1 can be obtained from the inclination of the approximate straight line of the process of (1), and the external specific surface area S3 can be obtained from the inclination of the approximate straight line of the process of (3). Then, the internal specific surface area S2 can be calculated by subtracting the external specific surface area S3 from the total specific surface area S1.

Incidentally, the measurement of the adsorption isotherm of the CNT-containing fibrous carbon nanotube structure, the preparation of t-plot, and the analysis of t-plot can be used to calculate the total specific surface area S1 and the internal specific surface area S2. For example, "BELSORP (registered trademark) - mini" (manufactured by BEL Co., Ltd.) of a commercially available measuring device.

Further, the CNT-containing fibrous carbon nanostructure having the above properties. For example, it can be efficiently produced by the following method (ultra-growth method; refer to International Publication No. 2006/011655) by supplying a raw material compound and a carrier gas to a handle for manufacturing a carbon nanotube on the surface. In the case of synthesizing CNTs by chemical vapor deposition (CVD) on a substrate of a dielectric layer, a trace amount of an oxidizing agent (catalyst activating substance) is present in the system, and the catalytic activity of the catalyst layer is dramatically improved. . In the following, there is a case where a carbon nanotube obtained by the super-growth method is referred to as "SGCNT".

Further, the CNT-containing fibrous carbon nanotube structure produced by the ultra-growth method may be composed of only SGCNT, or may be composed of SGCNT and a non-cylindrical carbon nanostructure. Specifically, the CNT-containing fibrous carbon nanotube structure may include a single-layer or multi-layered flat cylindrical carbon nanotube structure (hereinafter referred to as "graphene nanobelt (GNT)"), which The single or multi-layered flat cylindrical carbon nanostructures have a full length and have a strip portion that is adjacent or subsequent between the inner walls.

Here, in the case of the synthesis of GNT, a band-like portion which is close to or next between the inner walls is formed over the entire length, and a six-membered ring network structure of carbon is estimated to form a flat cylindrical material. Moreover, the shape of the GNT is a flat cylindrical shape and there is a band portion close to or in the vicinity of the inner wall of the GNT, for example, a GNT and a fullerene (C60) can be sealed in a quartz tube, using a transmissive type. Electron microscopy (TEM) observation of the fullerene obtained by heat treatment under reduced pressure (fullerene insertion treatment) was inserted into GNT because there was a portion (band portion) in which no fullerene was inserted in GNT. So I can confirm.

In addition, for GNT, the phrase "having a strip-shaped portion over the entire length" means "60% or more, preferably 80% or more, more preferably 100% continuous or intermittently having a strip-shaped portion" throughout the length (full length) in the longitudinal direction.

Further, the shape of the GNT is preferably a shape having a strip-shaped portion at the central portion in the width direction, and a shape having a straight cross section in the extending direction (axial direction), and a cross-sectional length in the vicinity of both end portions in the longitudinal direction of the cross-section. It is preferable that the largest dimension in the direction orthogonal to the direction is larger than the largest dimension in the direction orthogonal to the longitudinal direction of the cross section in the vicinity of the central portion in the longitudinal direction of the cross section, and the dumbbell shape is Very good.

Here, the cross-sectional shape of the GNT refers to a section from the center line of the length of the cross section (the line passing through the longitudinal direction of the cross section and orthogonal to the longitudinal direction line). In the region of 30% or less of the length direction, the term "near the end portion in the longitudinal direction of the cross section" means a region on the outer side in the longitudinal direction of "the vicinity of the central portion in the longitudinal direction of the cross section".

Moreover, the carbon nanostructure containing GNT as a non-cylindrical carbon nanostructure can be formed by a predetermined method by using a substrate having a catalyst layer on its surface and synthesizing CNTs by a super-growth method. It is obtained by a substrate having a catalyst layer on its surface (hereinafter referred to as a "catalyst substrate"). Specifically, the carbon nanostructure system containing GNT can be obtained by synthesizing CNT by a super-growth method using a catalyst substrate, wherein the catalyst substrate can be coated with a coating liquid A containing an aluminum compound. After coating onto the substrate, drying the applied coating liquid A to form an aluminum thin film (catalyst supporting layer) on the substrate, coating the coating liquid B containing the iron compound on the aluminum thin film, and at a temperature The coating liquid B to be applied is dried at 50 ° C or lower, and an iron thin film (catalyst layer) is formed on the aluminum thin film.

[[Properties of fibrous carbon materials]]

Further, the average fiber diameter of the fibrous carbon material is preferably 1 nm or more, more preferably 3 nm or more, still more preferably 2 μm or less, and still more preferably 1 μm or less. When the average fiber diameter of the fibrous carbon material is within the above range, the fibrous carbon material can be sufficiently dispersed in the polymer material, and at the same time, the physical properties of the obtained composite material can be sufficiently improved. Here, the aspect ratio of the fibrous carbon material is preferably greater than 10.

Further, in the present invention, the "average fiber diameter" can be obtained by measuring the diameter (outer diameter) of 100 randomly selected fibrous carbon materials using a transmission electron microscope.

[solvent]

Further, the solvent (dispersion medium of the fibrous carbon material) of the dispersion liquid is not particularly limited, and examples thereof include water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and third. Alcohols such as butanol, pentanol, hexanol, heptanol, octanol, decyl alcohol, decyl alcohol, amyl alcohol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, etc. Esters, ethyl acetate, butyl acetate, etc., diethyl ether, two An ether such as dioxane or tetrahydrofuran, a guanamine-based polar organic solvent such as N,N-dimethylformamide or N-methylpyrrolidone, toluene, xylene or chlorobenzene An aromatic hydrocarbon such as o-dichlorobenzene or p-dichlorobenzene. These may be used alone or in combination of two or more types.

[Additive for Dispersion]

In addition, the additive for the dispersion liquid which can be arbitrarily prepared in the dispersion liquid is not particularly limited, and examples thereof are generally used for preparing a dispersion liquid such as a dispersant. Further, for example, when the solvent is removed from the dispersion by filtration, From the viewpoint of preventing clogging of the filter paper, and suppressing the decrease in physical properties (for example, electrical conductivity) of the obtained composite material, the amount of the additive for the dispersion such as a dispersant is preferably a small amount.

In addition, the dispersing agent used for the preparation of the dispersion liquid is not particularly limited as long as it can disperse the fibrous carbon material and can be dissolved in the solvent described above, and a surfactant, a synthetic polymer or a natural polymer can be used.

Here, examples of the surfactant include sodium dodecyl sulfate, sodium deoxycholate, sodium cholate, and sodium dodecylsulfonate. Further, examples of the synthetic polymer include a polyether diol, a polyester diol, a polycarbonate diol, a polyvinyl alcohol, a partially saponified polyvinyl alcohol, an ethylene acetylated modified polyvinyl alcohol, and an acetal. Modified polyvinyl alcohol, butyral modified polyvinyl alcohol, stanol-modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer, ethylene-vinyl alcohol-vinyl acetate copolymerized resin, dimethylamine B Acrylate, dimethylamine ethyl methacrylate, acrylic resin, epoxy resin, modified epoxy resin, phenoxy resin, modified phenoxy resin, phenoxy ether resin, benzene An oxyester resin, a fluorine-based resin, a melamine resin, an alkyd resin, a phenol resin, a polypropylene decylamine, a polyacrylic acid, a polystyrene sulfonic acid, a polyethylene glycol, a polyvinylpyrrolidone or the like.

Further, examples of the natural polymer include starch of polysaccharides, pullulan, polydextrose, dextrin, guar gum, xanthan gum, and linear chain. Starch, amylopectin, alginic acid, gum arabic, carageenan, chondroitin sulfate, hyaluronic acid, curdlan, chitin, chitosan (chitosan), cellulose, and its salts or derivatives. Moreover, the dispersing agents can be used in one type or in two types. Mix and use.

[Properties of dispersion]

Further, it is preferable that the dispersion liquid is an aggregate which cannot be confirmed by 1 mm or more by visual observation. Moreover, it is preferable that the fibrous carbon material in the dispersion is dispersed at a level of 150 μm or less when the value of the median diameter (average particle diameter) is measured by using a particle size distribution meter. When the fibrous carbon material is well dispersed in the dispersion liquid, the dispersibility of the easily dispersible aggregate obtained by removing the solvent can be improved, so that the fibrous carbon material can be more preferably dispersed in the polymer material. The physical properties of the composite material are further enhanced.

Further, the solid content concentration of the dispersion liquid is preferably 0.001% by mass or more and 20% by mass or less, depending on the type of the fibrous carbon material. When the solid content concentration is less than 0.001% by mass, the amount of the easily dispersible aggregate obtained by removing the solvent is small, and there is a possibility that the production efficiency of the composite material cannot be sufficiently improved. Further, when the solid content concentration is more than 20% by mass, the dispersibility of the fibrous carbon material in the dispersion liquid is lowered, and at the same time, the viscosity of the dispersion liquid is increased and the fluidity is lowered.

[Preparation of dispersion]

Further, in the method for producing a composite material of the present invention, a commercially available dispersion obtained by dispersing an aggregate of fibrous carbon materials in a solvent may be used, but the dispersion is applied before the easy dispersibility assembly preparation step. The dispersion prepared by the preparation step is preferably a dispersion. In particular, from the viewpoint of using a fibrous carbon material to be well dispersed in a solvent, the fibrous carbon material is more preferably dispersed in the polymer material by further improving the dispersibility of the easily dispersible aggregate. In addition, as a dispersion, a fibrous carbon material is added to a solvent. The crude dispersion is preferably a dispersion obtained by providing a cavitation effect or a pulverization effect to the dispersion.

Specifically, in the method for producing a composite material of the present invention, a coarse dispersion liquid obtained by adding the above-described fibrous carbon material and an optional additive for a dispersion liquid to the above solvent is used, and the crude dispersion liquid is supplied thereto. As described in detail below, it is preferred that the dispersion treatment of the cavitation effect or the dispersion treatment of the pulverization effect can be obtained.

[[Can obtain the dispersion treatment of cavitation effect]]

The dispersion treatment capable of obtaining a cavitation effect is a method of dispersing a pulsation wave generated by cracking of a vacuum bubble generated in water when high energy is applied to a liquid. By using this dispersion method, the fibrous carbon material can be well dispersed.

Here, specific examples of the dispersion treatment capable of obtaining a cavitation effect include dispersion treatment by ultrasonic waves, dispersion treatment by jet polishing, and dispersion treatment by high shear stirring. These dispersion treatments may be carried out only in one type, or may be carried out by combining a plurality of dispersion treatments. More specifically, a dispersion treatment of the cavitation effect can be obtained, and for example, an ultrasonic homogenizer (HOMOGENIZER), a jet milling, and a high shear stirring device can be suitably used. These devices can be used by prior practitioners.

When the ultrasonic homogenizer is used for the dispersion of the fibrous carbon material, the ultrasonic wave is irradiated to the coarse dispersion using an ultrasonic homogenizer. The irradiation time may be appropriately set in accordance with the amount of the fibrous carbon material or the like. For example, it is preferably 3 minutes or longer, preferably 30 minutes or longer, more preferably 5 hours or shorter, and preferably 2 hours or shorter. Further, for example, the output power is 20 W or more and 500 W or less. Preferably, it is preferably 100 W or more and 500 W or less, and the temperature is preferably 15 ° C or more and 50 ° C or less.

In the case of the blasting, the number of times of the treatment may be appropriately set in accordance with the amount of the fibrous carbon material or the like. For example, it is preferably two or more, more preferably 100 or less, and preferably 50 or less. Further, for example, the pressure is preferably 20 MPa or more and 250 MPa or less, and the temperature is preferably 15 ° C or more and 50 ° C or less.

Further, when high shear stirring is used, the coarse dispersion is stirred and sheared using a high shear stirring device. The faster the rotation speed, the better. For example, the operation time (time of mechanical rotation operation) is preferably 3 minutes or longer and 4 hours or shorter, and the peripheral speed is preferably 5 m/sec or more and 50 m/sec or less, and the temperature is 15 ° C or more and 50 ° C or less. It is better.

Further, the above-described dispersion treatment capable of obtaining a cavitation effect is preferably carried out at a temperature of 50 ° C or lower. This is because the concentration change of the dispersion caused by the evaporation of the solvent can be suppressed.

[[Can achieve the dispersion treatment of the crushing effect]]

It is possible to obtain a dispersing treatment for the pulverization effect, and it is possible to uniformly disperse the fibrous carbon material in a solvent, and it is possible to suppress the smashing wave at the time of bubble elimination as compared with the above-described dispersion treatment capable of obtaining a cavitation effect. Damage to fibrous carbon materials is advantageous in this regard.

The dispersion treatment capable of obtaining the pulverization effect enables the agglomerates of the fibrous carbon material to be pulverized by applying a shear force to the coarse dispersion. The dispersion is carried out, and the coarse dispersion liquid is back-loaded, and the coarse dispersion liquid is cooled as needed to suppress the generation of bubbles, and the fibrous carbon material can be uniformly dispersed in the solvent. Further, when the coarse dispersion is back-loaded, the back pressure applied to the coarse dispersion may be Take it down to atmospheric pressure in one breath, but it is better to use multi-stage pressure reduction.

Here, in order to apply a shearing force to the coarse dispersion to further disperse the fibrous carbon material, for example, a dispersion system having a disperser having the following configuration may be used. That is, the disperser is provided with a disperser orifice having an inner diameter d1, a dispersion space having an inner diameter d2, and a terminal portion having an inner diameter d3 (but d2>d3) from the inflow side of the crude dispersion toward the outflow side. >d1).

Further, in the disperser, a coarse dispersion of a high pressure (for example, 10 to 400 MPa, preferably 50 to 250 MPa) which flows in is passed through the orifice of the disperser, and becomes a fluid having a high flow rate as the pressure is lowered. Flow into the scattered space. Subsequently, the coarse dispersion having a high flow rate which has flowed into the dispersion space flows at a high speed in the dispersion space and is subjected to shearing force at this time. As a result, the flow rate of the crude dispersion is lowered, and the fibrous carbon material is well dispersed. Further, the lower pressure (back pressure) flow system flows out from the terminal portion as a dispersion of the fibrous carbon material as compared with the pressure of the inflowing crude dispersion.

Further, the back pressure of the crude dispersion can be such that the coarse dispersion can be loaded by applying a load to the flow of the coarse dispersion, for example, by providing a multistage pressure reducer on the downstream side of the disperser, the coarse dispersion can be made. The back pressure required for the load. Further, by using a multi-stage pressure reducer and reducing the back pressure of the coarse dispersion in multiple stages, when the dispersion of the fibrous carbon material is finally released to atmospheric pressure, generation of bubbles in the dispersion can be suppressed.

Further, the disperser may be provided with a heat exchanger and a coolant supply mechanism for cooling the coarse dispersion. Since the coarse dispersion liquid which is heated at a high temperature by applying a shear force to the disperser is cooled, generation of bubbles in the coarse dispersion liquid can be further suppressed. Further, the crude dispersion liquid is cooled in advance instead of providing a heat exchanger or the like. It is also possible to suppress generation of bubbles in a solvent containing a fibrous carbon material.

As described above, in the dispersion treatment capable of obtaining the pulverization effect, since cavitation can be suppressed, it is possible to suppress damage of the fibrous carbon material which is sometimes caused by cavitation, and particularly, the scouring wave caused by the bubble elimination. Damage to the resulting fibrous carbon material. Further, it is possible to suppress the bubble from adhering to the fibrous carbon material or the energy loss due to the generation of the bubbles, and to uniformly and efficiently disperse the fibrous carbon material.

The dispersion system having the above-described configuration includes, for example, the product name "BERYU SYSTEM PRO" (manufactured by the company). Further, the dispersion treatment for obtaining the pulverization effect can be carried out by appropriately controlling the dispersion conditions using such a dispersion system.

<Removal of solvent>

The method of removing the solvent from the dispersion is not particularly limited, and a known solvent removal method such as drying or filtration can be used. In particular, from the viewpoint of efficiently removing the solvent, it is preferred to use a method of removing the solvent, drying under reduced pressure, vacuum drying or filtration. Further, from the viewpoint of easily and promptly removing the solvent, as a method of removing the solvent, it is preferred to use filtration, and it is more preferable to use a reduced pressure filtration. When the solvent is quickly and efficiently removed, it is possible to suppress the aggregation of the fibrous carbon material once dispersed once, and to improve the dispersibility of the obtained easily dispersible aggregate. Here, the solvent in the dispersion liquid does not have to be completely removed, and the fibrous carbon material remaining after the solvent removal can be operated in the form of an aggregate (easily dispersible aggregate), and there is no problem even if the solvent remains. . Further, when the solvent is removed by filtration, a sheet-like easily dispersible aggregate having excellent handleability can be usually obtained.

(Composite Modulation Step)

In the composite material preparation step, the easily dispersible aggregate obtained by the easy dispersibility assembly preparation step is mixed with the polymer material to obtain a composite material containing the polymer material and the fibrous carbon material. Further, in the composite material preparation step, a composite material containing a polymer material, a fibrous carbon material, and an additive for any composite material can be prepared, and when a composite material containing an additive for a composite material is prepared, the composite material preparation step is easily dispersed. The aggregate, the polymer material, and the composite material may be mixed with an additive.

Further, in the composite material preparation step, the easily dispersible aggregate composed of the fibrous carbon material dispersed in the solvent at one time is mixed with the polymer material, whereby the fibrous carbon material is dispersed in the matrix of the polymer material. Therefore, the fibrous carbon material can be well dispersed to prepare a composite material having excellent physical properties.

<easy dispersibility aggregate>

As the easily dispersible aggregate, an easily dispersible aggregate obtained by the easy dispersibility aggregate preparation step can be used. Here, the amount of the easily dispersible aggregate to be mixed with the polymer material is preferably 0.01 parts by mass or more per 100 parts by mass of the polymer material, and is preferably 0.1 parts by mass or more. 10 parts by mass or less is preferred, and it is preferably 5 parts by mass or less. When 0.01 parts by mass or more of the easily dispersible aggregate is mixed per 100 parts by mass of the polymer material, the physical properties of the obtained composite material can be sufficiently improved. In addition, when the amount of the polymerizable material per 100 parts by mass of the easily dispersible aggregate is 10 parts by mass or less, the fibrous carbon material can be favorably dispersed in the matrix of the polymer material, and the preparation is sufficiently excellent. a composite of physical properties.

<Polymer material>

The polymer material is not particularly limited, and a known resin can be used in accordance with the use of the composite material. Specifically, as the polymer material, a thermoplastic resin or a thermosetting resin can be used. Further, in the present invention, the rubber and the elastic system are provided as being contained in the "resin". Further, a thermoplastic resin or a thermosetting resin may be used in combination.

[Thermoplastic resin]

Further, examples of the thermoplastic resin include poly(2-ethylhexyl acrylate), a copolymer of acrylic acid and 2-ethylhexyl acrylate, polymethacrylic acid or an ester thereof, polyacrylic acid or an ester thereof, and the like. Acrylic resin; polyoxyn resin; fluororesin of polyvinylidene fluoride, polytetrafluoroethylene, etc.; polyethylene; polypropylene; ethylene-propylene copolymer; polymethylpentene; polyvinyl chloride; polyvinylidene chloride (polyvinylidene chloride); polyvinyl acetate; ethylene-vinyl acetate copolymer; polyvinyl alcohol; polyacetal; polyethylene terephthalate; polybutylene terephthalate; polyethylene naphthalate; Polystyrene; polyacrylonitrile; styrene-acrylonitrile copolymer; acrylonitrile-butadiene-styrene copolymer (ABS resin); styrene-butadiene block copolymer or its hydride; styrene- Isoprene block copolymer or hydrogenated product thereof; polyphenylene ether; modified polyphenylene ether; aliphatic polyamine; aromatic polyamine; polyamidoximine; Ester; polyphenylene sulfide; polyfluorene; polyether oxime; polyether nitrile; polyether ketone; Ketones; polyurethane; liquid crystal polymer; ionic polymer and the like. These may be used alone or in combination of two or more.

[thermosetting resin]

Further, examples of the thermosetting resin include natural rubber; butadiene rubber. Rubber; isoprene rubber; nitrile rubber; hydrogenated nitrile rubber; chloroprene rubber; ethylene propylene rubber; chlorinated polyethylene; chlorosulfonated polyethylene; butyl rubber; halogenated butyl rubber; polyisobutylene rubber Epoxy resin; polyimine resin; bis-xenylene diimide resin; benzocyclobutene resin; phenol resin; unsaturated polyester; diallyl phthalate resin; Oxide resin; polyurethane; thermosetting polyphenylene ether; thermosetting modified polyphenylene ether. These may be used alone or in combination of two or more.

<Additives for composite materials>

As an additive for a composite material, a known additive can be used in accordance with the use of the composite material. In particular, as an additive for a composite material, it is preferred to use a particulate carbon material. This is because if the granular carbon material is blended in the composite material, the physical properties (for example, electrical conductivity, thermal conductivity, and the like) of the composite material can be further improved.

In addition, the additive for the composite material other than the particulate carbon material is not particularly limited, and examples thereof include an antioxidant, a thermal stabilizer, a photosetter, an ultraviolet absorber, a crosslinking agent, a pigment, a colorant, and a foaming agent. Antistatic agents, flame retardants, slip agents, softeners, adhesion-imparting agents, plasticizers, mold release agents, deodorants, perfumes, and the like.

[Grained carbon material]

Here, the suitable particulate carbon material which is an additive for a composite material is not particularly limited, and examples thereof include artificial graphite, flaky graphite, exfoliated graphite, natural graphite, acid-treated graphite, and expanded graphite. Graphite such as expanded graphite; carbon black or the like. These may be used alone or in combination of two or more.

In particular, as the granular carbon material, it is preferred to use expanded graphite. This is because if expanded graphite is used, the physical properties of the composite material can be made (for example) Such as thermal conductivity) further improved. In addition, the expanded graphite which is a particulate carbon material can be suitably used. For example, the expandable graphite obtained by chemically treating graphite such as flaky graphite with sulfuric acid or the like can be expanded by heat treatment and then obtained by miniaturization. . In addition, examples of the expanded graphite include EC1500, EC1000, EC500, EC300, EC100, and EC50 (all of which are trade names) manufactured by Ito Graphite Industries Co., Ltd., and the like.

Further, the average particle diameter of the particulate carbon material is preferably 0.1 μm or more, more preferably 1 μm or more, still more preferably 500 μm or less, and most preferably 250 μm or less. This is because if the average particle diameter of the particulate carbon material is within the above range, the composite material can be further improved.

Further, the aspect ratio (long diameter/short diameter) of the granular carbon material is preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less. Further, in the "average particle diameter" of the present invention, the maximum diameter (long diameter) can be measured for any 50 granular carbon materials by using SEM (scanning electron microscope), and the measured long diameters can be calculated. The number average is used to find. Further, in the present invention, the "aspect ratio" is a measurement of the maximum diameter (long diameter) and the particle diameter in the direction orthogonal to the maximum diameter of any 50 granular carbon materials by SEM (scanning electron microscope) (short diameter) And, the average value of the ratio of the long diameter to the short diameter (long diameter / short diameter) is calculated and obtained.

In addition, the amount of the particulate carbon material to be mixed with the polymer material and the easily dispersible aggregate is preferably 10 parts by mass or more per 100 parts by mass of the polymer material, and more preferably 100 parts by mass or more. It is preferable to set it as 400 mass parts or less, and it is preferable to set it as 300 mass parts or less. When the polymer material is mixed with 10 parts by mass or more of the particulate carbon material per 100 parts by mass of the polymer material, the physical properties of the obtained composite material can be sufficiently improved. Also, if the polymer material is 100 mass When the amount of the particulate carbon material is 400 parts by mass or less, the granular carbon material can be favorably dispersed in the matrix of the polymer material, and at the same time, the particulate carbon material can be prevented from being dropped.

<mixing>

The method of mixing the polymer material, the easily dispersible aggregate, and the optional additive for the composite material is not particularly limited, and a known mixing method can be used. Specifically, as the mixing method, for example, the following methods (1) to (2) can be used.

(1) A solid or molten polymer is used in a kneading device such as an open roll, a kneader, a Banbury mixer, a uniaxial kneader or a biaxial kneader. A method of kneading a material, an easily dispersible aggregate, and an arbitrary composite material with an additive.

(2) A method in which a polymer material, an easily dispersible aggregate, and an arbitrary composite material are stirred and mixed in the presence of a small amount of a solvent.

In addition, when the mixing method of the above (2) is used, the amount of the solvent used is preferably 1000 parts by mass or less per 100 parts by mass of the polymer material from the viewpoint of efficiently producing the composite material. Further, the solvent to be used can be removed from the composite material by a known method such as natural drying, heat drying, or vacuum defoaming.

(composite material)

Further, the composite material produced by the above-described production method exhibits excellent conductivity and excellent thermal conductivity because the fibrous carbon material is well dispersed in the matrix of the polymer material. Therefore, the composite material produced by the above-described production method can be formed into an arbitrary shape by a known molding method. In the form of a vulcanization or the like, it is used as a conductive sheet, a thermally conductive sheet, a conductive plastic, a semiconductor wafer, a thermally conductive paint, a sealant, a gasket, or the like.

Example

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited by the examples. In addition, in the following description, the "%" and "part" of the quantity are indicated as the quality standard unless otherwise notified in advance. In the examples and comparative examples, the properties of the dispersion, the conductivity of the composite material, and the production efficiency were measured or evaluated by the following methods.

<Properties of dispersion>

The fibrous carbon material (fibrous carbon) was measured by using a laser diffraction/scattering particle size distribution measuring apparatus (LA-960, manufactured by Horiba, Ltd.) for the dispersion of the aggregate of the fibrous carbon material by visual observation. The median diameter (average particle diameter) of the nanostructure.

In addition, the dispersion liquid in which the aggregate of the fibrous carbon material was not able to be visually observed was diluted to 10 times, and the dynamic light scattering type particle size distribution measuring apparatus (SZ-100, manufactured by Horiba, Ltd.) was used. The average particle diameter (accumulated diameter) was measured by cumulative analysis of a fibrous carbon material (fibrous carbon nanostructure).

<Electrical conductivity of composite materials>

Four square test pieces each having a size of 10 mm × 10 mm were cut out from the molded body to obtain a measurement sample.

In addition, a low resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product name "Loresta (registered trademark) GPMCP-T610") is used, and it is based on JIS K7194. The method measures the conductivity of the test sample. Specifically, the measurement sample was fixed on an insulating plate, and the probe was placed in contact with the center position of the measurement sample (5 mm in length and 5 mm in width), and a voltage of 10 V was applied to measure the conductivity of each measurement sample. Further, the average value of the measured values is obtained and set as the electrical conductivity of the composite material.

<Manufacturing efficiency of composite materials> [For Example 1, Comparative Example 1 and Comparative Example 2]

The time required for removing the solvent at the time of preparing the composite material was measured, and the production efficiency of the composite material was evaluated in accordance with the following criteria.

○: The time required to remove the solvent or remove the solvent is less than 10 hours

×: The time required to remove the solvent is 10 hours or more

[For Example 2, Comparative Example 3, and Comparative Example 4]

The total amount of the solvent (isopropyl alcohol) used in the preparation of the composite material was calculated, and the production efficiency of the composite material was evaluated in accordance with the following criteria.

○: The amount of the solvent to be used is 3,000 parts by mass or less based on 100 parts by mass of the obtained composite material

×: the amount of the solvent used is more than 3,000 parts by mass relative to 100 parts by mass of the obtained composite material

(Modulation of fibrous carbon nanotube structure A containing CNT)

The SGCNT was prepared in accordance with the ultra-growth method (refer to International Publication No. 2006/011655), and was used as the carbon nanostructure A. Further, when the obtained fibrous carbon nanotube structure A (SGCNT) was evaluated and analyzed, the BET specific surface area was 800 m ² /g, and the average diameter was 3 nm.

(Example 1)

<Modulation of Polymer Materials>

In the reactor, 100 parts of a monomer mixture composed of 2-ethylhexyl acrylate 94% and 6% acrylic acid, 0.03 parts of 2,2'-azobisisobutyronitrile and 700 parts of ethyl acetate were added uniformly. After dissolution and nitrogen substitution, the mixture was polymerized at 80 ° C for 6 hours. The polymerization conversion ratio was 97%. The obtained polymer was dried under reduced pressure to evaporate ethyl acetate to obtain a viscous solid polymer material A (acrylate polymer). The acrylate polymer had a weight average molecular weight (Mw) of 270,000 and a weight average molecular weight (Mw) / number average molecular weight (Mn) of 3.1.

Further, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined by gel permeation chromatography using tetrahydrofuran as an eluent, and were obtained in terms of standard polystyrene.

<Preparation of dispersion>

400 mg of fibrous carbon nanotube structure A as a fibrous carbon material was weighed and mixed in 2 L of methyl ethyl ketone as a solvent, and stirred for 2 minutes using a homogenizer to obtain a crude dispersion. The obtained crude dispersion liquid was circulated by a wet spray-grinding 0.5 mm flow path 2 under a pressure of 100 MPa using a wet jet mill (manufactured by Soka Co., Ltd., JN-20) to make a fibrous carbon nanostructure. The body A is dispersed in methyl ethyl ketone. Further, a dispersion A having a solid content concentration of 0.20% by mass was obtained.

Further, when the properties of the obtained dispersion A were evaluated, the median diameter (average particle diameter) of the fibrous carbon nanotube structure A in the dispersion A was 24.1 μm.

<Modulation of easily dispersible aggregates>

The obtained dispersion A was decompressed using Kiriyama filter paper (No. 5A) Filtration was carried out to obtain a flaky dispersible aggregate A.

<Modulation of composite materials>

200 parts by mass of expanded graphite as a granular carbon material (manufactured by Ito Graphite Industries, Ltd., trade name "EC-50", average particle diameter: 250 μm), 100 parts by mass of polymer material A, and 3 parts by mass of easy dispersibility In the presence of 20 parts of ethyl acetate as a solvent, the aggregate A was stirred and mixed for 1 hour using a Hobart mixer (trade name "ACM-5LVT type" manufactured by Kosei Kogyo Co., Ltd.), and the obtained mixture was vacuumed. After defoaming for 1 hour, ethyl acetate was removed while defoaming to obtain a composite material A containing fibrous carbon nanostructures A, expanded graphite, and polymer material A. Moreover, the production efficiency of the composite material was improved. Evaluation. The results are shown in Table 1.

<Modulation of a molded body>

The obtained composite material A was put into a pulverizer and pulverized for 10 seconds. Next, 5 g of the obtained pulverized material was sandwiched with a PET film (protective film) having a thickness of 50 μm subjected to sandblast treatment, at a roll gap of 330 μm, a roll temperature of 50 ° C, a roll line pressure of 50 kg/cm, and a roll speed. Under a condition of 1 m/min, calender molding was carried out to obtain a conductive sheet (molded body composed of a composite material) having a thickness of 0.3 mm. Further, the conductivity of the composite material was evaluated using the obtained molded body. The results are shown in Table 1.

(Comparative Example 1)

Except that the preparation of the dispersion and the preparation of the dispersible aggregate are not carried out, the fibrous carbon nanostructure A which is peeled off from the catalyst substrate is replaced by the dispersible aggregate A when the composite material is prepared, and The composite material and the molded body were prepared in the same manner as in Example 1 except that the amount was 3 parts by mass in the direct state. and Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)

<Modulation of Polymer Materials>

Polymer material A was obtained in the same manner as in Example 1.

<Preparation of dispersion>

400 mg of fibrous carbon nanotube structure A as a fibrous carbon material and 400 mg of carboxymethylcellulose (manufactured by Daicel Fine Chemical, weight average molecular weight (Mw) 300,000) as a dispersing agent were mixed in 2 L of water as a solvent. The mixture was stirred for 2 minutes using a homogenizer to obtain a crude dispersion. The obtained crude dispersion was circulated by wet-jet-milled 0.5 mm flow path 40 under a pressure of 100 MPa using a wet jet mill (manufactured by Soka Co., Ltd., JN-20) to make a fibrous carbon nanostructure. A is dispersed in water. Further, a dispersion B having a solid concentration of 0.20% by mass was obtained.

Further, the properties of the obtained dispersion B were evaluated, and the cumulative diameter of the fibrous carbon nanostructure A in the dispersion B was 1,700 nm.

<Modulation of composite materials>

200 parts by mass of expanded graphite as a granular carbon material (trade name "EC-50" manufactured by Ito Graphite Industries Co., Ltd., average particle diameter: 250 μm), 100 parts by mass of polymer material A, and 1500 parts of dispersion B ( The solid content was converted into 3 parts), and the mixture was stirred and mixed for 1 hour using a Hobart mixer (trade name "ACM-5LVT type" manufactured by Kosei Seisakusho Co., Ltd.), and the obtained mixture was subjected to vacuum defoaming for 10 hours in defoaming. At the same time, water is removed to obtain a composite material B containing the fibrous carbon nanostructure A, the expanded graphite, and the polymer material A.

Further, in the same manner as in Example 1, the production efficiency of the composite material was evaluated. The results are shown in Table 1.

<Modulation of a molded body>

A molded article was prepared in the same manner as in Example 1 except that the composite material B was used instead of the composite material A. Further, the conductivity of the composite material was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 2)

<Modulation of Polymer Materials>

To 2 L of isopropyl alcohol which was stirred at 5000 rpm using a disperser, 200 g of a latex of nitrile rubber (manufactured by ZEON, Japan, Nipol 1562, solid content concentration: 50%) was dropped. Then, the produced coagulum was filtered, taken out, and dried to obtain a polymer material B (nitrile rubber).

<Preparation of dispersion>

In the same manner as in Example 1, a dispersion A having a solid concentration of 0.20% by mass was obtained.

<Modulation of easily dispersible aggregates>

The sheet-like easily dispersible aggregate A was obtained in the same manner as in Example 1.

<Modulation of composite materials>

100 parts by mass of the polymer material B and 3 parts by mass of the easily dispersible aggregate A were kneaded by using an open roll having a roll interval of 0.5 mm to obtain a composite containing the fibrous carbon nanostructure A and the polymer material B. Material C. Moreover, the manufacturing efficiency of the composite material was evaluated. The results are shown in Table 2.

<Modulation of a molded body>

The obtained composite material C was subjected to vacuum compression molding under vacuum at a temperature of 120 ° C, a pressure of 0.4 MPa, and a pressurization time of 5 minutes to obtain a circular film having a diameter of 40 to 60 mm and a thickness of 100 to 500 μm. a molded body composed of a composite material). Further, the obtained molded body was used to evaluate the electrical conductivity of the composite material. The results are shown in Table 2.

(Comparative Example 3)

Except that the preparation of the dispersion and the preparation of the dispersible aggregate are not carried out, the fibrous carbon nanostructure A which is peeled off from the catalyst substrate is replaced by the dispersible aggregate A when the composite material is prepared, and The composite material and the molded body were prepared in the same manner as in Example 2 except that the amount was 3 parts by mass in the direct state. Further, evaluation was carried out in the same manner as in Example 2. The results are shown in Table 2.

(Comparative Example 4) <Preparation of dispersion>

In the same manner as in Comparative Example 2, a dispersion B having a solid concentration of 0.20% by mass was obtained.

<Modulation of composite materials>

200 parts (100 parts by solid content) of latex of nitrile rubber (manufactured by ZEON, Japan, Nipol 1562, solid content: 50%) and 1500 parts (solid content: 3 parts) of dispersion B were stirred and mixed to obtain a mixture. liquid. Further, the obtained mixed liquid was dropped into 5000 parts of isopropyl alcohol. And use The resulting coagulum was recovered by vacuum filtration to obtain a composite material D containing fibrous carbon nanostructures A and nitrile rubber.

Further, in the same manner as in Example 2, the production efficiency of the composite material was evaluated. The results are shown in Table 2.

<Modulation of a molded body>

A molded article was prepared in the same manner as in Example 2 except that the composite material D was used instead of the composite material C. Further, the conductivity of the composite material was evaluated in the same manner as in Example 2. The results are shown in Table 2.

It can be seen from Tables 1 and 2 that the composite materials of Examples 1 and 2 obtained by mixing the easily dispersible aggregate and the polymer material have excellent physical properties and can be efficiently produced.

Industrial use possibility

By using the method for producing a composite material of the present invention, a composite material having excellent physical properties can be efficiently produced. Further, according to the present invention, a composite material having excellent physical properties can be obtained.

Claims (9)

A method for producing a composite material comprising the steps of: removing a solvent from a dispersion of a fibrous carbon material in a solvent to obtain an easily dispersible aggregate of fibrous carbon material; and dispersing the foregoing The step of mixing the aggregate with the polymer material to obtain a composite material containing the polymer material and the fibrous carbon material. The method for producing a composite material according to the first aspect of the invention, further comprising: a coarse dispersion liquid obtained by adding a fibrous carbon material to a solvent, and providing a dispersion treatment capable of obtaining a cavitation effect or a pulverization effect to obtain the foregoing The step of dispersing the liquid. The method for producing a composite material according to claim 1, wherein the solvent is removed by filtration of the dispersion. The method for producing a composite material according to claim 1, wherein the fibrous carbon material contains a fibrous carbon nanostructure. The method for producing a composite material according to claim 4, wherein the fibrous carbon nanostructure comprises a carbon nanotube. The method for producing a composite material according to claim 4, wherein the fibrous carbon nanostructure has a BET specific surface area of 400 m ² /g or more. The method for producing a composite material according to the first aspect of the invention, wherein the polymer material is mixed with the easily dispersible aggregate in a ratio of 0.01 part by mass or more and 10 parts by mass or less per 100 parts by mass of the polymer material. The method for producing a composite material according to the first aspect of the invention, wherein the composite material further comprises a particulate carbon material, the easy dispersibility aggregate, the polymer material, and the granular carbon material. The materials were mixed to obtain the aforementioned composite material. A composite material produced by using the method for producing a composite material according to any one of claims 1 to 8.