JP2022131867A - Carbonaceous granulated material and manufacturing method of carbonaceous granulated material - Google Patents

Abstract

To provide a carbonaceous granulated material having excellent handling ability and a manufacturing method of the carbonaceous granulated material.SOLUTION: A carbonaceous granulated material of the present invention has a structure of an aggregate of carbonaceous material particles, and has a particle size D50 which is a cumulative frequency of 50% in a cumulative frequency distribution curve based on a volume measured by using a laser diffraction type grain size distribution measuring apparatus of 1 μm or over and 100 μm or under. Moreover, a manufacturing method of manufacturing the carbonaceous granulated material of the present invention involves the steps of: carbonizing a raw resin to obtain a carbide; pulverizing the carbide to obtain a carbonaceous material slurry; and atomizing and drying the carbonaceous material slurry to obtain a carbonaceous granulated material.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a carbon material granule and a method for producing the carbon material granule. More specifically, the present invention relates to a carbon material granule for a colorant produced by carbonizing a raw material resin such as a thermosetting resin, and a method for producing the carbon material granule.

Carbon black, titanium-based black pigments, and transition metal compounds such as black iron oxide (iron black) are used as black colorants for molding materials.

As an example, in Patent Document 1, as a black coloring agent for a semiconductor encapsulant that can form a semiconductor encapsulant that has excellent dispersibility in a resin component, a high volume resistivity value, and an excellent light-shielding property, Suitable carbon black colorants are described.
As another example, Patent Document 2 discloses a semiconductor sealing material that suppresses electrical defects due to electrical conduction between inner leads and wires, and has excellent moldability, reliability, laser marking properties, etc. Colorants and resin compositions are described.

JP-A-2006-52279 JP-A-2007-134361

Conventional black colorants such as those described in the above documents are very fine particles with a particle size of several tens to several hundreds of nanometers. There was a problem that the sex was bad. As a result, there are problems such as contamination of the working environment, difficulty in uniform dispersion in the molding material, and adherence of particles to powder-contacting parts.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide carbon material granules with good handleability.
Another object of the present invention is to provide a method for producing the carbon material granules.

A black colorant as described above was artificially granulated to reduce scattering and cohesiveness to obtain granules with improved handleability. In addition, in order to uniformly disperse the granules in the resin composition for molding when blended into the resin composition, the granules are made to be easily pulverized and dispersed by the shearing stress of a known kneader.

As a result of studies, the inventors completed the invention provided below and solved the above problems.

According to the invention,
A carbon material granule having a structure in which carbon material particles are aggregated,
The particle diameter D50 at which the cumulative frequency is ₅₀ % in the volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution analyzer is 1 μm or more and 100 μm or less.
Carbon material granules are provided.

Moreover, according to the present invention,
a carbonization step of carbonizing the raw material resin to obtain a carbide;
a pulverizing step of pulverizing the carbide to obtain a carbon material slurry;
a granulation step of spray-drying the carbon material slurry to obtain carbon material granules;
A method for producing carbon material granules is provided, comprising:

ADVANTAGE OF THE INVENTION According to this invention, the carbon material granule which is excellent in handleability, and the manufacturing method of the said carbon material granule are provided.

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

In this specification, the notation "X to Y" in the description of numerical ranges means X or more and Y or less, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".

As used herein, "aggregation" refers to a phenomenon in which particles spontaneously clump together due to van der Waals forces, electrostatic adhesion forces, and the like. In addition, "aggregation" refers to solidification of particles by an artificial operation or method, unlike agglomeration. Furthermore, the term "primary particles" refers to particles that constitute the powder at the time of powder production, and in which intermolecular bonds remain as they are. "Secondary particles" refer to aggregated primary particles.

As used herein, the term "average particle size" refers to a particle size _D50 at which the cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution analyzer.

<Carbon material granules>
First, the carbon material granules of this embodiment will be described.

The carbon material granules of the present embodiment have a structure in which carbon material particles are aggregated.

Conventional carbon materials are extremely fine particles with a particle size of several tens to several hundreds of nanometers. Therefore, the scattering, cohesiveness, and adhesiveness are very high, and the work environment is polluted when the particles scatter during normal handling.
In addition, when the carbon material particles are mechanically kneaded into a resin composition or the like, for example, if they agglomerate in the resin composition due to Van der Waals force, electrostatic adhesion force, or the like, they are dispersed by mechanical kneading. becomes very difficult. As a result, it cannot be uniformly dispersed in the final resin composition, resulting in color unevenness.

Therefore, by artificially granulating the carbon material particles, the carbon material granules with reduced scattering properties and cohesion properties and improved handling properties were obtained. By reducing the above properties, the carbon material granules of the present embodiment can prevent contamination of the working environment and adhesion of particles to the powder-contacting part, resulting in improved handling properties. In addition, in order to uniformly disperse the granules in the resin composition for molding when blended into the resin composition, the granules are made to be easily pulverized and dispersed by the shearing stress of a known kneader.

Here, the "carbon material particles" preferably include primary particles, secondary particles in which primary particles are agglomerated, or mixtures thereof.
Carbon material particles include secondary particles that are difficult to crush due to agglomeration of fine primary particles of carbon material, as well as primary particles with relatively large particle sizes and low cohesive force, resulting in a wide particle size distribution. becomes. In that case, for example, when the carbon material particles are kneaded into a resin composition or the like, the carbon material particles tend to aggregate before kneading, resulting in color unevenness in the kneaded resin composition.

On the other hand, as in the present embodiment, by artificially granulating the carbon material particles to form "carbon material granules", for example, when the carbon material granules are kneaded into a resin composition or the like. , the carbon material granules are pulverized into the carbon material particles in the form of fine primary particles and secondary particles by the shear stress caused by the rotor during kneading, and the carbon material particles are relatively uniform in the resin composition. disperse to As a result, there is an effect that color unevenness of the resin composition can be prevented.

The lower limit of the average particle diameter _D50 of the carbon material granules in the present embodiment is preferably 1 μm, more preferably 5 μm, and still more preferably 10 μm.
By setting the _D50 to the above lower limit or higher, the carbon material granules are reduced in scattering property, cohesion property and adhesion property, and handling property is improved.
The upper limit of the average particle size _D50 of the carbon material granules in the present embodiment is preferably 100 μm, more preferably 90 μm, and even more preferably 80 μm.
By setting the _D50 to the above upper limit or less, uneven coloring is reduced when mixed with the resin composition for molding.

In the carbon material granules in the present embodiment, the particle diameter D10 at which the cumulative frequency is ₁₀ % in the volume-based cumulative frequency distribution curve is preferably 0.5 μm to 50 μm, more preferably 2 μm to 45 μm. It is preferably 5 μm to 40 μm, more preferably 5 μm to 40 μm.
When the _D10 is within the above numerical range, the handling property when kneading the carbon material granules with the resin composition is improved.

In addition, the carbon material granules in the present embodiment preferably have a particle diameter D90 at which the cumulative frequency is ₉₀ % in the volume-based cumulative frequency distribution curve is 3 μm to 150 μm, more preferably 8 μm to 140 μm. It is preferably 16 μm to 130 μm, more preferably 16 μm to 130 μm.
When the _D90 is within the above numerical range, when the carbon material granules are kneaded with the resin composition, the carbon material granules are uniformly dispersed in the resin composition, and color unevenness of the resin composition is eliminated. can be prevented.

The particle size distribution represented by the following formula (1) of the carbon material granules in the present embodiment is preferably 0.9 to 4.0, more preferably 0.9 to 3.0. , 0.9 to 2.5.
When the particle size distribution is within the above numerical range, when the carbon material granules are kneaded with the resin composition, the carbon material granules are uniformly dispersed in the resin composition, and the color unevenness of the resin composition is reduced. can be prevented.
Particle size distribution=(D ₉₀ −D ₁₀ )/D ₅₀ Equation (1)

The shape of the carbon material granules in the present embodiment is desirably spherical or substantially spherical. By making the shape of the carbon material granules any of the above shapes, the fluidity of the carbon material granules is improved, and the cohesiveness and adhesion are reduced, so that the handleability is improved. preferable.

Here, "perfectly spherical" means that the degree of circularity is from 0.8 to 1.0, and "substantially spherical" means that the degree of circularity is from 0.6 to 0.8. The "circularity" is obtained by dividing the perimeter of a circle having the same area as the observed particle image by the perimeter of the particle image. Assuming that the area of the particle image is S and the perimeter is L, it can be expressed by the following formula (2).
Circularity=(4πS) ^1/2 /L Expression (2)

A more preferable form of the carbon material granules in the present embodiment is excellent in compression breaking strength. Specifically, the lower limit of the compressive breaking strength measured using a microcompression tester is preferably 1 kPa, more preferably 5 kPa, and even more preferably 10 kPa. By setting the compressive breaking strength to the above lower limit or more, it is preferable because it is not easily crushed during normal handling and the handling property is improved.
Also, the upper limit of the compressive breaking strength is preferably 200 kPa, more preferably 150 kPa, and even more preferably 100 kPa. By setting the compressive breaking strength to the above upper limit or less, the carbonaceous material granules are easily crushed when kneaded into the molding resin composition and uniformly dispersed in the molding resin composition. preferred because

A more preferable form of the carbon material granules in the present embodiment is excellent in compressibility. In addition, in this specification, the degree of compression (%) is calculated by the following formula (3).
Compressibility (%)=(1−(loose bulk density (g/cm ³ )/firm bulk density (g/cm ³ )))×100 Equation (3)
Here, the loose bulk density indicates the density obtained by dividing the mass of the carbon material granules by the bulk volume occupied by them. It can be obtained from the mass and the volume of the container by filling it in the container. In addition, the hardened bulk density indicates the density measured after hardening the carbon material granules filled in the container by tapping in the loose bulk density measurement.
For the measurement of these loose bulk densities and firm bulk densities, known methods and devices such as a powder tester can be used.

Specifically, the degree of compression in a more preferred form of the carbon material granules in the present embodiment is preferably 5% to 30%, more preferably 10% to 30%, and still more preferably 15% to 30%. is.
When the degree of compression is equal to or less than the upper limit, the fluidity of the carbon material granules is favorable. Further, when the degree of compression is equal to or higher than the lower limit, the carbon material granules have good handleability.

A more preferable form of the carbon material granules in the present embodiment is excellent in degree of cohesion. In this specification, the degree of aggregation (%) is defined as the weight remaining on each sieve after 2 g of the carbon material granules are placed in three sieves and subjected to constant vibration for a predetermined period of time. It is represented by the following formula (4).
Degree of cohesion (%) = ((Residual weight of upper sieve (g))/2 + 3 (Residual weight of middle sieve (g))/10 + (Residual weight of lower sieve (g))/10) x 100 Formula (4)

Specifically, the aggregation degree in a more preferred form of the carbon material granules in the present embodiment is preferably 10% to 50%, more preferably 10% to 40%, and still more preferably 10% to 30%. is.
If the degree of aggregation is equal to or less than the upper limit, the fluidity of the carbon material granules will be favorable. In addition, when the degree of agglomeration is equal to or higher than the lower limit, the carbon material granules have good handleability.

A more preferable form of the carbon material granules in the present embodiment has excellent dispersibility. In this specification, the degree of dispersion (%) refers to the weight before dropping a certain amount of the above carbon material granules from a certain height and the weight before dropping onto a watch glass placed below. It is the ratio of the weight that scatters without the weight, and is represented by the following formula (5).
Degree of dispersion (%) = (scattered weight (g)/weight before falling (g)) x 100 Equation (5)

Specifically, the degree of dispersion in a more preferred form of the carbon material granules in the present embodiment is preferably 10% to 50%, more preferably 10% to 40%, and still more preferably 10% to 30%. is.
When the degree of dispersion is equal to or less than the upper limit, the carbon material granules are prevented from scattering and have favorable fluidity. In addition, when the degree of agglomeration is equal to or higher than the lower limit, the carbon material granules have good handleability.

In the more preferable form of the carbon material granules of the present embodiment, the balance between the fluidity and the handleability can also be confirmed from the angle of repose and the angle of collapse.
In this specification, the angle of repose (°) refers to the angle formed by the free surface of the deposited layer formed by allowing the carbon material granules to fall freely due to sinusoidal vibration and the free surface of the deposited layer. The collapse angle (°) refers to the inclination angle of the collapsed surface formed by applying the same impact to the repose angle of the deposit layer three times to cause it to collapse.

Specifically, the angle of repose in a more preferred form of the carbon material granules in the present embodiment is preferably 20° to 50°, more preferably 25° to 40°, and still more preferably 25° to 35°. is.

Further, the collapse angle in a more preferable form of the carbon material granules in the present embodiment is specifically preferably 5° to 20°, more preferably 5° to 15°, and still more preferably 5° to 20°. 10°.

<Manufacturing method of carbon material granules>
Next, a method for producing the carbon material granules of the present embodiment will be described.

The carbon material granules in this embodiment can be produced preferably by a production method including the following three steps.
That is, a carbonization step of carbonizing the raw material resin to obtain a carbide;
a pulverizing step of pulverizing the carbide to obtain a carbon material slurry;
and a granulation step of spray-drying the carbon material slurry to obtain carbon material granules.

Each step in the method for producing the carbon material granules according to the present embodiment will be described in more detail below.

(Carbonization process)
First, in the carbonization step, a carbonized product of the raw resin composition is obtained by carbonizing the raw resin composition. As a method for obtaining the carbide of the raw material resin composition, equipment capable of heat treatment under an inert gas atmosphere is preferably used. Known gases such as nitrogen, helium gas and argon gas can be used as the inert gas.

The carbonization temperature in the carbonization step is preferably 400°C to 1500°C. Further, by adjusting the carbonization temperature according to the application of the final compact, the electrical properties of the carbon material granules in the present embodiment can be adjusted. When increasing the volume resistivity of the carbon material granules, the carbonization temperature is more preferably 400°C to 750°C, and even more preferably 500°C to 700°C. Conversely, when lowering the volume resistivity of the carbon material granules, the carbonization temperature is more preferably 750.degree. C. to 1500.degree. C., even more preferably 800.degree.

The carbonization time in the carbonization step is not particularly limited, but is preferably 1 hour to 24 hours, more preferably 1 hour to 12 hours, and still more preferably 1 hour to 6 hours.

The raw material resin composition of the carbon material granules in the present embodiment is not particularly limited, but is selected from, for example, thermosetting resins, thermoplastic resins, and other polymeric materials (hereinafter simply referred to as "main component may be referred to as "resins").
Although the raw material resin composition of the present invention may use only one type of resin as the main component resins, this is also referred to as the raw material resin composition for the sake of convenience.

Here, the thermosetting resin is not particularly limited, but examples include phenolic resins such as novolak-type phenolic resins and resol-type phenolic resins, epoxy resins such as bisphenol-type epoxy resins and novolak-type epoxy resins, aniline resins, melamine resins, and urea. Nitrogen-containing resins such as resins, furan resins, and the like can be used.
Moreover, the thermoplastic resin is not particularly limited, but examples thereof include polystyrene, polyamide, polyamine, polyimine, and polypropylene.
Other polymeric materials are not particularly limited, but include, for example, petroleum pitch, coal pitch, polymerizable high molecular weight materials such as pitch for spinning, and the like.
The main component resins may be used alone or in combination of two or more.

In the raw material resin composition of the present embodiment, when a thermosetting resin is used as such main component resins, a curing agent thereof can be used in combination.
The curing agent for the thermosetting resin is not particularly limited, but for example, hexamethylenetetramine when using a novolak-type phenol resin, polyamine compounds such as aliphatic polyamines and aromatic polyamines when using an epoxy resin, acid anhydride substances, imidazole compounds, and the like can be used.
It should be noted that even a thermosetting resin that is usually used in combination with a curing agent can be used without a curing agent in the raw material resin composition of the present invention.

In the raw material resin composition of the present embodiment, additives can be blended in addition to the main component resins.
Although the additive is not particularly limited here, for example, carbon material precursor carbonized at 200 to 800 ° C., graphite and graphite modifier, organic acid, inorganic acid, nitrogen-containing compound, oxygen-containing compound, aromatic compound , and non-ferrous metal elements.
The above additives can be used alone or in combination of two or more depending on the type and properties of the main component resins used.

Equipment capable of heat treatment that can be used in the carbonization step of the present embodiment is not particularly limited, and known equipment can be selected. Known facilities include, for example, a batch-type electric furnace or a continuous furnace such as a rotary kiln or a roller hearth kiln.
The equipment may be used alone or in combination of two or more depending on the physical properties required for the carbon material granules, the production efficiency of the carbon material granules, and the like.

(Pulverization process)
Then, a pulverization step is performed. In the pulverization step, the carbide obtained in the carbonization step is pulverized to obtain a carbon material slurry. At this time, it is preferable that the pulverization step includes a preliminary pulverization step of dry-pulverizing the carbide to obtain a pre-pulverized material, and a fine pulverization step of wet-pulverizing the pre-pulverized material to obtain the carbon material slurry.

Details of each step in the pulverization step will be described below.

(Preliminary pulverization step)
In the preliminary pulverization step, the carbide obtained in the carbonization step is dry-pulverized to obtain a pre-pulverized material. The particle size of the pre-pulverized product is not particularly limited, but dry pulverization is preferably carried out until it becomes 1 μm to 100 μm, more preferably 1 μm to 80 μm, even more preferably 1 μm to 50 μm.

The device used in the preliminary pulverization step is not particularly limited, and known devices such as rod mills, ball mills, bead mills, jet mills, cyclone mills, roller mills, pin mills, hammer mills and pulperizers can be used.
The above equipment can be used alone or in combination of two or more depending on the physical properties and handling properties of the pre-ground material.

(Fine pulverization process)
In the fine pulverization step, the preliminary pulverized material obtained in the preliminary pulverization step is further wet-pulverized to obtain a carbon material slurry. The particle size of the carbon material particles contained in the carbon material slurry is not particularly limited, but wet pulverization is preferably performed until the particle size becomes 0.05 μm to 0.5 μm, more preferably 0.05 μm to 0.4 μm, and 0.05 μm to 0.4 μm. 05 μm to 0.3 μm is more preferable.

The device used for the pulverization step is not particularly limited, and known devices such as a high-pressure homogenizer and a bead mill can be used.
The above equipment can be used alone or in combination depending on the physical properties and handling properties of the carbon material slurry.
From the viewpoint of further miniaturizing the carbon material particles in the carbon material slurry, it is preferable to use a bead mill.

When a bead mill is used in the fine pulverization step, the material of the beads used is not particularly limited, and beads of known materials such as zirconia beads, alumina beads, zircon beads, glass beads, and high-chromium carbon steel beads can be used. . Among these, it is preferable to use zirconia beads from the viewpoint of metal contamination, abrasion resistance, and pulverization efficiency.

The bead diameter may be selected according to the particle size and hardness of the pre-pulverized product, and is, for example, 0.03 mm to 1 mm. Moreover, two or more kinds of beads having different particle diameters may be used in combination.

It is preferable to use water, an organic solvent, or a mixture thereof as a dispersion medium for dispersing the preliminary pulverized material during the wet pulverization. A known organic compound having a boiling point of 120° C. or less can be used as the organic solvent. Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol, and ketones such as acetone, 2-butanone and 4-methyl-2-pentanone.

The concentration of the carbon material slurry during wet pulverization is preferably 1 wt % to 50 wt %, more preferably 1 wt % to 40 wt %, even more preferably 1 wt % to 30 wt %.
When the concentration of the carbon material slurry is equal to or less than the above upper limit, the fluidity of the carbon material slurry is increased, and the preliminary pulverized material can be pulverized more satisfactorily, which is preferable. Further, it is preferable that the concentration of the carbon material slurry is equal to or higher than the above lower limit because the pulverization efficiency of the pre-pulverized material is improved.

(Granulation process)
Finally, in the granulation step, the carbon material slurry obtained in the pulverization step is spray-dried in a drying chamber to obtain carbon material granules.
Although the method of spray drying is not particularly limited, for example, spray drying can be performed using a spray dryer or the like.

When a spray dryer is used, it is preferable to send gas heated by an electric heater or the like into the drying chamber and spray the carbon material slurry into the drying chamber using a nozzle. By spraying the carbon material slurry, the carbon material slurry becomes spherical or approximately spherical due to the surface tension of the dispersion medium. As a result, the carbon material particles in the carbon material slurry are condensed in a spherical or approximately spherical shape, and the dispersion medium dries to give the carbon material granules a desirable shape.

The nozzle used for spraying the carbon material slurry into the drying chamber is not particularly limited, and a known nozzle capable of spraying droplets can be used. As known nozzles, for example, a two-fluid nozzle, a pressurized nozzle, a disk atomizer, or the like can be used.
The gas used for spraying is not particularly limited, but it is desirable to use the same kind of gas as the gas in the drying chamber.
The gas pressure at this time is preferably 0.1 MPa to 0.5 MPa, more preferably 0.1 MPa to 0.4 MPa, and even more preferably 0.1 MPa to 0.3 MPa.

The drying temperature in the granulation step is preferably 100°C to 300°C, more preferably 125°C to 250°C, still more preferably 150°C to 250°C. When the drying temperature is equal to or lower than the above upper limit, bumping of the dispersion medium used in the carbon material slurry does not occur, and the shape of the carbon material granules becomes more uniform, which is preferable. Moreover, it is preferable that the drying temperature is equal to or higher than the above lower limit because the drying becomes smooth.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

Embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted that the invention is not limited to the examples only.

<Example 1>
(Adjustment of carbide)
A phenol resin (PR-51464 manufactured by Sumitomo Bakelite Co., Ltd.) was carbonized at 1300° C. for 2 hours in a nitrogen atmosphere to obtain a carbide.

(Adjustment of carbon material slurry)
After that, the obtained carbide was pulverized with a jet mill to obtain a pre-pulverized material having an average particle size D ₅₀ of 9.8 μm. 10 parts by weight of the preliminary pulverized material is dispersed in 90 parts by weight of water, and further finely pulverized with a wet bead mill using zirconia beads of Φ0.3 mm, so that the carbon material particles with an average particle diameter _D50 of 0.33 μm are concentrated. A carbonaceous slurry dispersed at 10% by weight was obtained.

(Manufacture of carbon material granules)
The above carbon material slurry was spray-dried using a spray dryer (hot air inlet temperature: 150°C, gas: air, two-fluid nozzle pulverization air pressure: 0.2 MPa) to obtain carbon material granules. The average particle size _D50 of the carbon material granules of Example 1 was 12.6 μm. Compressive breaking strength and powder properties of this carbon material granule were evaluated. Table 1 shows the evaluation results.

<Example 2>
After pulverizing the carbide obtained in Example 1 with a jet mill, it was further pulverized with a dry bead mill using Φ1.0 mm zirconia beads to obtain a pre-pulverized material having an average particle size D ₅₀ of 1.3 μm. 15 parts by weight of the preliminary pulverized material is dispersed in 85 parts by weight of water, and further finely pulverized with a wet bead mill using zirconia beads of Φ0.1 mm, so that the carbon material particles with an average particle diameter _D50 of 0.14 μm are concentrated. A carbonaceous slurry dispersed at 15% by weight was obtained. Carbon material granules were obtained in the same manner as in Example 1 from the above carbon material slurry. The average particle size _D50 of the carbon material granules of Example 2 was 21.2 μm. Compressive breaking strength and powder properties of this carbon material granule were evaluated. Table 1 shows the evaluation results.

<Example 3>
The carbide obtained in Example 1 was pulverized by the method of Example 2 to obtain a pre-pulverized material having an average particle size D ₅₀ of 1.3 μm. 20 parts by weight of the preliminary pulverized material is dispersed in 80 parts by weight of water, and further finely pulverized with a wet bead mill using zirconia beads of Φ0.1 mm, so that the carbon material particles with an average particle diameter _D50 of 0.16 μm are concentrated. A carbon material slurry dispersed at 20% by weight was obtained. Carbon material granules were obtained in the same manner as in Example 1 from the above carbon material slurry. The average particle diameter _D50 of the carbon material granules of Example 3 was 34.1 μm. Compressive breaking strength and powder properties of this carbon material granule were evaluated. Table 1 shows the evaluation results.

<Comparative Example 1>
The carbon material granules obtained in Example 1 were pulverized using a jet mill into carbon material particles having an average particle diameter _D50 of 0.32 μm, and the compression breaking strength and powder characteristics were evaluated. . Table 1 shows the evaluation results.

<Comparative Example 2>
The carbon material granules obtained in Example 2 were pulverized using a jet mill into carbon material particles having an average particle size _D50 of 0.15 μm, and the compression breaking strength and powder characteristics were evaluated. . Table 1 shows the evaluation results.

<Comparative Example 3>
The carbide obtained in Example 1 was pulverized with a jet mill to obtain carbon material particles having an average particle size _D50 of 11.2 μm. Compressive fracture strength and powder properties of the carbon material particles were evaluated. Table 1 shows the evaluation results.

<Comparative Example 4>
The carbide obtained in Example 1 was pulverized by the method of Example 2 to obtain a pre-pulverized material having an average particle size D ₅₀ of 1.3 μm. 3 parts by weight of the above preliminary pulverized product is dispersed in 97 parts by weight of water, and further finely pulverized with a wet bead mill using zirconia beads of Φ0.1 mm, so that the carbon material particles with an average particle diameter _D50 of 0.12 μm are concentrated. A carbon material slurry dispersed at 3% by weight was obtained. Carbon material granules were obtained in the same manner as in Example 1 from the above carbon material slurry. At this time, the pulverization air pressure of the two-fluid nozzle was changed to 0.25 MPa. The average particle diameter _D50 of the carbon material granules of Comparative Example 4 was 0.86 μm. Compressive breaking strength and powder properties of this carbon material granule were evaluated. Table 1 shows the evaluation results.

(Method for measuring particle size and particle size distribution)
A laser diffraction/scattering particle size distribution analyzer (LA-950, manufactured by HORIBA, Ltd.) was used to measure the particle size and particle size distribution of the carbon material granules or carbon material particles of Examples and Comparative Examples. did. A measurement solution was prepared by dispersing carbon material granules or carbon material particles in a nonionic surfactant as a dispersion medium and subjecting the dispersion to ultrasonic treatment.

(Method for evaluating compressive fracture strength)
A micro compression tester (manufactured by Shimadzu Corporation, MCT-210) was used to evaluate the compression breaking strength of the carbon material granules or carbon material particles of Examples and Comparative Examples. Compressive breaking strength was calculated from the load (mN) at the yield point when one grain of the sample set in the tester was compressed and the following formula (6) defined in JIS R 1639-5. In the following equations, the compressive breaking strength is expressed by CS (kPa), the load by _P (N), and the particle diameter by d (mm).
C _S =2.48 (P/(πd ² ) Equation (6)

(Method for evaluating powder properties and handling properties)
Various powder characteristics and handling properties of the carbon material granules or carbon material particles of Examples and Comparative Examples were measured using a powder characteristic evaluation apparatus Powder Tester (manufactured by Hosokawa Micron Corporation, PT-X).

(angle of repose)
The carbon material granules or carbon material particles of Examples and Comparative Examples are passed through a sieve with a mesh size of 710 μm, and while being vibrated at an amplitude of 1.5 mm, a funnel with an opening diameter of 7 mm is used to pass through the center of the table surface. A deposit layer was formed by dropping it onto a circular table from a height of 7.5 cm, and the angle formed by the free surface of the deposit layer and the horizontal plane was measured.

(collapse angle)
After the angle of repose was measured, the circular table was crushed by impacting it three times with a shocker, and the angle formed between the free surface of the collapsed sedimentary layer and the horizontal plane was measured.

(loose bulk density)
A bat attached to the powder tester, a tapping lift bar, a fixed chute, a chute bracket, a sieve with an opening of 710 μm, and a 100 cc bulk density measuring cup accurately weighed to 0.01 g were attached to the main body of the powder tester. 200 cc of the carbon material granules or carbon material particles of Examples and Comparative Examples were poured through a sieve vibrating with an amplitude of 1.5 mm set on the top of the chute, and overflowed so that the sample completely filled the measuring cup. Excess carbon material granules or carbon material particles protruding from the measuring cup are scraped off with the metal blade attached to the powder tester, and the weight of the measuring cup containing the carbon material granules or carbon material particles is accurately weighed to 0.01g. The loose bulk density was calculated by weighing and dividing by the volume of the measuring cup.

(hard bulk density)
A special cap is attached to the measuring cup filled with the carbon material granules or carbon material particles used for the measurement of the loose bulk density, and 100 cc of the carbon material granules or carbon material particles are further poured in in the same manner as above, The sample was allowed to overflow from the dedicated cap. After tapping 180 times with a stroke of 18 mm, the dedicated cap was removed. Scrape off the carbon material granules or carbon material particles protruding from the measuring cup with a metal blade, accurately weigh the measuring cup containing the carbon material granules or carbon material particles to 0.01 g, and measure the weight of the measuring cup. The compacted bulk density was calculated by dividing by the volume.

(cohesion)
A three-tiered sieve (upper: 355 μm mesh, middle: 250 μm mesh, lower: 150 μm mesh) was set, and 2 g of carbon material granules or carbon material particles of Examples and Comparative Examples were placed on the upper sieve. After applying vibration with an amplitude of 1 mm for 60 seconds, the remaining weight after sieving was measured, and the degree of agglomeration was calculated using the following formula (4).
Degree of cohesion (%) = ((Residual weight of upper sieve (g))/2 + 3 (Residual weight of middle sieve (g))/10 + (Residual weight of lower sieve (g))/10) x 100 Formula (4)

(dispersion degree)
10 g of the carbon material granules or carbon material particles of Examples and Comparative Examples were allowed to fall freely from a height of 61 cm, and the weight of the material scattered without falling onto a watch glass placed on a watch glass was measured. was used to calculate the degree of dispersion.
Degree of dispersion (%) = (scattered weight (g))/weight before falling (g)) × 100 Equation (5)

(Liquidity)
10 g of the carbon material granules or carbon material particles of Examples and Comparative Examples were weighed onto a medicine wrapping paper, and the medicine wrapping paper was shaken several times to evaluate the fluidity of the carbon material granules or carbon material particles according to the following criteria.
◯: The height of the powder crest during weighing and after shaking is less than 10 mm. △: The height of the powder crest during weighing is 10 mm or more, and the height of the powder crest after shaking. is less than 10 mm × … the height of the powder pile at the time of weighing and after shaking is 10 mm or more

The compressive breaking strength of the carbon material granules obtained in Examples 1 to 3 was all less than 100 kPa, and they could be easily pulverized and dispersed by the shear stress during kneading into the resin composition or the like. .
In addition, from the evaluation results of powder properties and handling properties, cohesiveness, dispersibility (dust scattering), fluidity, etc. were improved compared to the carbon material fine particles and carbon material granules of the comparative example, and handling was improved. improved sexuality.

Claims (15)

A carbon material granule having a structure in which carbon material particles are aggregated,
The particle diameter D50 at which the cumulative frequency is ₅₀ % in the volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution analyzer is 1 μm or more and 100 μm or less.
Carbon material granules. In the carbon material granules according to claim 1,
Carbon material granules, wherein the carbon material particles include primary particles, secondary particles in which primary particles are aggregated, or a mixture thereof. 3. The carbon material granules according to claim 1 or 2, wherein the shape of the carbon material granules is spherical or approximately spherical. The carbon material granules according to any one of claims 1 to 3, containing carbides of one or more materials selected from thermosetting resins, thermoplastic resins and polymerizable high molecular weight materials. , carbon material granules. The carbon material granules according to any one of claims 1 to 4, wherein the carbon material granules have a compression breaking strength of 1 kPa or more and 200 kPa or less as measured using a microcompression tester. In the carbon material granules according to any one of claims 1 to 5, the compressibility calculated by the following formula (3) from the loose bulk density and the hard bulk density measured using a powder tester is 5% or more. Carbon material granules, which is 30% or less.
(Formula (3))
Compressibility (%) = (1-(loose bulk density (g/cm ³ )/hard bulk density (g/cm ³ ))) x 100 The carbon material granules according to any one of claims 1 to 6, wherein the carbon material granules have an angle of repose measured using a powder tester of 20° or more and 50° or less. The carbon material granules according to any one of claims 1 to 7, wherein the collapse angle measured using a powder tester is 5° or more and 20° or less. A production method for producing the carbon material granules according to any one of claims 1 to 8,
a carbonization step of carbonizing the raw material resin to obtain a carbide;
a pulverizing step of pulverizing the carbide to obtain a carbon material slurry;
a granulation step of spray-drying the carbon material slurry to obtain carbon material granules;
A method for producing carbon material granules, comprising: A manufacturing method for manufacturing the carbon material granules according to claim 9,
The pulverization step is
a preliminary pulverization step of dry-pulverizing the carbide to obtain a pre-pulverized material;
a fine pulverization step of wet-pulverizing the pre-pulverized material to obtain the carbon material slurry;
A method for producing carbon material granules, comprising: The method for producing the carbon material granules according to claim 10,
Manufacture of carbon material granules, wherein the preliminary pulverization step is performed using one or more devices selected from rod mills, ball mills, bead mills, jet mills, cyclone mills, roller mills, pin mills, hammer mills and pulperizers. Method. The method for producing the carbon material granules according to claim 10 or 11,
A method for producing a carbon material granule, wherein the pulverization step is performed using one or two types of equipment selected from a high-pressure homogenizer and a bead mill. The method for producing the carbon material granules according to any one of claims 10 to 12,
A method for producing carbon material granules, wherein the dispersion medium in the fine pulverization step is water, an organic solvent, or a mixture thereof. The method for producing the carbon material granules according to any one of claims 9 to 13,
A method for producing carbon material granules, wherein the carbonization step is performed in an inert gas atmosphere at a carbonization temperature of 400°C or higher and 1500°C or lower. The method for producing the carbon material granules according to any one of claims 9 to 14,
A method for producing a carbon material granule, wherein the drying temperature in the granulation step is 100°C or higher and 300°C or lower.