JPH10330107A - Production of highly packable carbonaceous powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain compact carbonaceous powder excellent in packability by imparting a dynamic energy to carbonaceous powder to specify an apparent density ratio and a median diameter ratio between the non-treated powder and the treated powder. SOLUTION: Carbonaceous powder having an interlayer distance (d002 ) of <=0.345 nm and a crystallite size of >=10 nm is charged into a mixing device and ground by the application of a dynamic energy so as to give an apparent density ratio of >=1.1 and a median diameter ratio of >=1 between the non-treated powder and the treated powder. Thus, the highly packable carbonaceous powder having a median diameter of 5-50 μm and a BET method specific surface area of <=25 m<2> /g is obtained. The mixing device has a shaft and plural plow-like or saw tooth-like paddles fixed to the shaft in the device. The paddles form plural treating chambers in various phases. The inner wall surface of the device is formed in a cylindrical shape along the outermost line of the rotation of the paddles, and the space between the inner wall surface and the outermost line is minimized. The plural paddles are disposed on the shaft in its axial direction. One or plural screw type crushing blades capable of being rotated at a high rotation rate are disposed in one or many stages on the inner wall surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a highly-filled carbonaceous powder.

[0002]

2. Description of the Related Art Carbon and graphite products are used in many industrial fields such as electricity, semiconductors, iron and steel, non-ferrous metals, chemicals, glass, machinery, precision equipment, and nuclear power.
Widely used as machine parts. For example, when graphite is used as a lubricating filler or a conductive filler for plastics, because the shape is plate-like, the fluidity of the plastic is poor, and a smooth molded body surface and uniform internal strain were not obtained. Such a problem may be solved if graphite is subjected to spheroidization. Further, in actual use, carbon and graphite materials are often used after being molded into a certain shape. Normal,
Aggregates (fillers) such as coke, artificial graphite, and natural graphite
Mixing and binding agents (binders) such as phenol and synthetic resin and tar pitch, forming into a slurry, compression molding by extrusion or embedding, carbonization, calcination, and further graphitization to produce a molded carbon material Is common.

[0003] The bulk density as a molded body is high,
A carbon molded body having high strength, hardness and uniformity is called a so-called special carbon material, and is used as a kind of extreme material, and its use is expanding. In the case of special carbon materials, how to increase the apparent density of the molded body is a problem. In the molding method described above, it is inevitable that voids are formed only in the volatile matter of the binder in the finally obtained molded body, which is one of the causes of a decrease in the density of the molded body. To improve the apparent density, close-packing of fillers, improvement of carbonization yield of binder,
Re-impregnation and re-carbonization of pitch in voids in molded body, carbon deposition from gas phase in voids in molded body, imparting fusibility to filler itself, use of thermosetting polymer with large shrinkage during carbonization, heating There are methods such as compression processing (hot press). Among these, the method of measuring the closest packing of the filler is desired to be further improved as a basis of the molding technique. In addition, the effect of eliminating the step of re-impregnation of the carbon raw material in the liquid or gas phase into the voids of the molded body is also expected to improve the filling property of the filler.

In recent years, attention has been paid to the use of carbonaceous particles as electrode plates of new type secondary batteries as compacts. Since the molded body used for the electrode plate of the non-aqueous electrolyte secondary battery itself forms an interlayer ring compound, it is important that more carbon material be filled in a unit volume of the electrode plate. It is. Carbonaceous and graphitic particles (carbonaceous, graphitic and multi-layered carbonaceous materials containing them) have higher crystallinity and higher true density than non-graphitizable carbon materials. Therefore, if an electrode is formed using these carbon and graphite carbon materials,
High electrode filling properties can be obtained, and the volume energy density of the battery can be increased. When the electrode is composed of carbon and graphite-based powder, a powder and a binder are mixed, a slurry is prepared by adding a dispersion medium, and this is applied to a metal foil as a current collector,
Thereafter, a method of drying the dispersion medium is generally used. At this time, it is general to provide a step of further performing compression molding for the purpose of pressing the powder to the current collector, making the electrode plate thickness uniform, and improving the electrode plate capacity. By this compression step, the electrode plate density of the electrode is improved, and the energy density per volume of the battery is further improved.

[0005] However, carbonaceous and graphitic materials that are somewhat crystalline and are available as fillers generally have a flake-like, scale-like, or plate-like particle shape. When these carbonaceous and graphitic particles are formed into a molded body through the above-described production process, the filling properties of the particles themselves are insufficient, so that more voids than necessary are retained between the particles, and the amount of binder used is reduced. There was a problem that the apparent density of the final molded product could not be obtained high because it could not be held low.

For this reason, it is conceivable to reduce the particle size by performing a treatment such as pulverization of the carbonaceous powder. However, the filling property of the carbonaceous powder after the pulverization is reduced due to the crystal structure of the carbonaceous powder. .

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a production method for obtaining a highly-filled carbon powder.

[0008]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to achieve the above object, the shape and filling property of the filler are important in order to improve the filling property of the molded body. By subjecting the carbonaceous powder to mechanical energy treatment, a more spherical carbonaceous powder is obtained, and by using this as a filler, a dense carbon compact is finally obtained that exhibits high filling properties. And found that the present invention was achieved.

The method for producing a carbonaceous powder of the present invention has been completed based on such knowledge, and the apparent density ratio before and after the treatment is 1 by applying mechanical energy to the carbonaceous powder. And a median diameter ratio before and after the treatment is 1 or less. In addition, the interlayer distance (d0
02) is 0.345 nm or less, and the crystallite size (Lc) is 10 nm or more.

The median diameter of the highly-filled carbonaceous powder after the treatment is 5 to 50 μm, and the BET specific surface area is
It is not more than 25 m ² / g.
After mixing the carbonaceous powder subjected to the mechanical energy treatment so that the apparent density ratio before and after the treatment is 1.1 or more and the median diameter ratio before and after the treatment is 1 or less with an organic compound such as a condensed polycyclic compound, And a method for producing a multi-layered carbon powder for carbonizing the organic compound.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The carbonaceous powder that can be used in the present invention is a natural or artificial graphite powder or a carbonaceous powder that is a graphitization precursor. Although the carbonaceous and graphitic powders before the treatment are not particularly limited, when the graphite structure is finally formed, the interlayer distance (d002) is 0.345 nm or less, and the crystallite size (Lc) Is preferably 10 nm or more and the true density is 1.9 g / cc or more. The true density is more preferably 2.1 or more, still more preferably 2.2 or more, and most preferably 2.25 g / cc or more. Further, the interlayer distance (d00
2) is more preferably 0.337 nm or less, and 0.3
Most preferably, it is 36 nm or less. Crystallite size (Lc)
Is more preferably 30 nm or more, still more preferably 50 nm or more, and particularly preferably 100 nm or more.
The crystallinity of the carbonaceous powder can also be determined by electrochemical capacity using lithium ions. The carbonaceous powder used in the present invention is based on a half-cell having a charge / discharge rate of 0.2 mA / cm ^2. 270 mAh / g in electrical capacity
Or more, preferably 310 mAh / g or more, more preferably 330 mAh / g or more, and particularly preferably 350 mA.
h / g or more is preferable. That is, a highly crystalline carbon material to some extent developed carbon hexagonal network structure, when the metal ions are intercalated, C ₆
It is particularly preferable that the material be a material capable of forming a stage 1 structure containing a composition represented by Li and containing one lithium atom for six carbon atoms.

When the crystallinity of the carbonaceous or graphitic powder before the treatment is not so high, a heat treatment for increasing the crystallinity can be performed again after the mechanical energy treatment. When mechanical energy treatment is performed in a state where crystallinity is low, plane orientation is not advanced to a high degree, and disorder is remaining in the structure, the crushed surface is relatively isotropic due to its structure, and it is rounded It becomes easier to obtain processed products.

A highly crystalline carbon material having a developed carbon hexagonal network structure includes highly oriented graphite in which hexagonal mesh planes are largely grown in the plane orientation and isotropic graphite in which highly oriented graphite particles are aggregated in the same direction. High-density graphite. As the highly oriented graphite, natural graphite produced from Sri Lanka or Madagascar, so-called quiche graphite precipitated as supersaturated carbon from molten iron, and artificial graphite having some high graphite quality are preferably used.

[0014] Natural graphite is described in a book published in 1974 from the Industrial Technology Center Co., Ltd., in the section on graphite in "Pulverized Particle Process Technology", and in "HAND" published by Noyes Publications.
According to “BOOKOF CARBON, GRAPHITE, DIAMOND AND FULLERENES”, depending on its properties, flake graphite (Flake Glaphi
te), scaly graphite (Crystalline (Vein) Glaphite) and soil graphite (Amorphousu Glaphite). The degree of graphitization is
Scaly graphite is the highest at 100%, followed by 9% of scaly graphite.
9.9% and soil graphite is as low as 28%. The quality of natural graphite is determined by the major production areas and veins, and flaky graphite (FlakeGlaphite) is produced in Madagascar, China, Brazil, Ukraine, Canada, etc., and flaky graphite (Crysta
lline (Vein) Glaphite) mainly comes from Sri Lanka.
Soil graphite is mainly produced in the Korean Peninsula, China, Mexico, etc. Among these natural graphites, those that are finally used as fillers in the present invention include soil graphite, which generally has a small particle size and a low purity. Is preferably selected from flaky graphite and flaky graphite.

[0015] Artificial graphite is produced by heating petroleum coke or coal pitch coke at a temperature of 1500 to 3000 ° C in a non-oxidizing atmosphere. Any material that exhibits high electric capacity can be used. The size of the particles before the treatment is 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and still more preferably 30 μm or more in terms of median diameter. There is no particular upper limit on the size of the particles before the treatment, but the median diameter is preferably 1 m.
m, preferably 500 μm or less, more preferably 250 μm or less, particularly preferably 200 μm or less.

The filling structure of the powder particles depends on the size and shape of the particles, the degree of interaction between the particles, and the like. As an index for quantitatively discussing the filling structure, an apparent density or a filling ratio is used. The apparent density indicates the mass per unit filling volume, and is also called bulkiness. Apparent density = mass of filled powder / filled volume of powder In the present invention, mechanical energy treatment is performed so that the apparent density ratio before and after treatment becomes 1.1 or more and the median diameter ratio before and after treatment becomes 1 or less. The reason why the mechanical energy is applied to improve the filling property of the carbonaceous powder is to obtain a dense carbon material.

The apparent density ratio before and after the treatment in the present invention is a tap density ratio before and after the treatment, where the tap density before the treatment is the denominator and the tap density after the treatment is the numerator. Various expressions have been proposed as expressions representing tap filling behavior. As an example, the following equation: ρ−ρ _{n =} A · ex
p (−kn) can be mentioned. Here, ρ is the apparent density at the end of filling, ρn is the apparent density at the time of filling n times, and k and A are constants. The apparent density (tap density) of the present invention is the apparent density (ρ ₁₀₀₀ ) at the time of filling the 20 cc cell 1000 times with taps, and the final apparent density ρ.
Refers to what is considered.

The median diameter ratio before and after the treatment is defined as the median diameter of the volume-based particle size distribution using the median diameter before the treatment as a denominator and the median diameter after the treatment as a numerator, as measured by a laser particle size distribution analyzer. It is a diameter ratio. The measurement principle of the laser type particle size measurement is that particles having anisotropic shape are averaged isotropically, and a particle size distribution substantially converted into a sphere can be obtained.

It is known that in order to enhance the filling property of powder particles, it is better to fill smaller particles so as to inscribe the voids formed between the particles. That is, as the number of particles (coordination number n) in contact with one particle (particle of interest) in the powder particle group increases, the proportion of the voids in the packed layer decreases. In other words, factors that affect the filling factor are the particle size ratio and the composition ratio, that is, the particle size distribution is important.

However, these studies were conducted on a group of model spherical particles, and the carbonaceous and graphitic particles before treatment handled in the present invention were in the form of flakes, scales, and plates. As it is, the particle size distribution is controlled simply by classification, etc.
Attempts to increase the filling rate cannot produce such a high filling state.

In general, if the particle size distribution shifts toward the smaller particle size as a whole, the coordination number increases, the porosity decreases, and as a result, it can be expected that the packing property is improved. . However, when the relationship between the particle diameter and the packing property of the actual flaky, scaly, and plate-like carbonaceous and graphitic powders is arranged, the filling property tends to deteriorate as the particle diameter decreases. That is, the smaller the particle size, the lower the filling property. In other words, the coordination number did not increase as expected. This is due to the fact that protruding graphitic fine particles, which can be called `` saddle '', `` peeling off '', and `` bending '', are connected to the surface of the graphitic powder particles with a certain degree of strength, and these are connected to adjacent particles. It is considered that the number of contacts is significantly reduced.

According to the investigations of the present inventors, it has been confirmed that the apparent density (tap density) of the carbonaceous particles having substantially the same true density and substantially the same median diameter shows a higher value as the shape is spherical. I have. That is, it is important that the shape of the particles be rounded and approximate to a spherical shape. If the particle shape approaches a spherical shape, the filling property of the powder is also greatly improved.

In the shape analysis, SEM observation in a particle state or a cross section of a molded product, images of thousands of particles dispersed in a liquid are taken one by one using a CCD camera, and the average is taken. Flow-type particle image analysis capable of calculating shape parameters, sedimentation velocity in liquid, BET specific surface area, sphere-converted specific surface area calculated from particle size distribution, ratio of both specific surface areas, and the like were used.

In the present invention, the apparent density of the powder is used as an index of the degree of spheroidization for the above reasons. When the filling property of the granular material after the treatment is higher than that before the treatment, it can be considered that the particles are spheroidized by the treatment method used. The apparent density ratio before and after the treatment is 1.1 or more, preferably 1.3 or more, more preferably 1.4 or more, and still more preferably 1.7 or more.

The apparent density after the treatment is 0.5 g / cc.
The above values are preferable, but the preferable values differ depending on the median diameter. When the median diameter is B μm, B
Is 40 or less, it is preferable that the measured apparent density is larger than the A value with respect to the A value defined by the following formula. A = −0.012 + 3.29 × 10 ⁻² × B−5.41 ×
When 10 ⁻⁴ × B ² B is 40 or more, the apparent density is 0.6 g / cc.
The above are preferred. In particular, in the entire median diameter region, it is more preferably 0.65 g / cc or more,
It is particularly preferred that it be 0.7 g / cc or more. The apparent density here has a slightly different absolute value depending on the measurement method, but is obtained by the tap method and is based on Kawakita's formula.

The mechanical energy treatment referred to in the present invention is to reduce the particle size so that the median diameter ratio of the powder before and after the treatment becomes 1 or less, and at the same time, to control the shape. Among the engineering unit operations that can be used for particle design such as mixing, granulation, surface modification, and reaction, it belongs to the pulverization process. Grinding refers to applying a force to a substance to reduce its size and adjust the particle size, particle size distribution, and filling properties of the substance. The pulverization process is classified according to the type of force applied to the substance and the processing mode. Here, the types of forces are a smashing force (impact force), a crushing force (compression force), a crushing force (milling force), and a shaving force (shearing force).
It is roughly divided into four. On the other hand, treatment forms are roughly classified into two types: volume pulverization in which cracks are generated and propagated inside the particles, and surface pulverization in which the particle surface is scraped off. Volume pulverization proceeds by impact force, compression force, and shear force, and surface pulverization proceeds by attrition force and shear force. Pulverization is a treatment in which the types of forces applied to these objects to be crushed and the processing forms are combined in various ratios.

In order to carry out the pulverization, a chemical reaction such as blasting or volume expansion may be used. However, it is usually general to use a mechanical device such as a pulverizer. These pulverization processes classified according to a combination of a method of applying a force and a processing mode are properly used according to the purpose of the process. The pulverization treatment used in the present invention is preferably a treatment in which the proportion of the surface treatment is finally high, regardless of the presence or absence of volume pulverization during the pulverization. In other words, in the initial stage of the pulverization process, the median diameter decreases, but after that stage has progressed to some extent, the rate of change in the particle diameter decreases, and conversely, the surface pulverization proceeds, and from the surface of the workpiece, A process in which the pulverization proceeds so that the corner can be removed is preferable. Alternatively, a process is preferred in which weak surface pulverization proceeds, the particle shape changes while the particle size remains substantially constant, and a rounded powder is obtained.

According to the study of the present inventors, when volume pulverization is actively performed, the filling property is not improved, and the particle shape is only reduced in particle size, and no large change in shape can be observed. Was. This is presumably because the graphite powder particles used in the present invention have a flaky, scaly, or plate-like form. Industrially available graphite materials are polycrystalline. However, graphite microcrystals in the material are likely to be aligned in a specific direction and therefore have considerable anisotropy in various properties. The mechanical strength is also one of the properties in which anisotropy appears, and the graphitic powder particles having a flake-like, scale-like, or plate-like morphology have a property of being easily cleaved parallel to the bottom surface. Therefore, in the process of actively performing volume pulverization, it is difficult to introduce roundness into the particle shape because the particle diameter is reduced while cleavage is involved.

The median diameter ratio before and after the treatment is preferably 1 or less. When granulation occurs, the median diameter ratio becomes 1 or more, and the apparent density also increases. But,
It is fully expected that the granulated powder will return to the original state before the treatment in the final molding process, which is not preferable. In order to round off the carbon and graphite powder particles and to introduce roundness into the particle shape, it is important that surface grinding is performed. It is important to determine the crushing ability possessed. The former is to select the type of device according to the type of crushing force applied to the object to be crushed, and the latter is to utilize the limit of crushing force (crushing limit) that exists for each device model.

Regarding the selection of the type of the device, it has been clarified by the inventors that the type of the device in which the pulverization proceeds by the shearing force is effective. As a device for advancing the surface pulverization, first, a device using a pulverizing medium such as a ball mill, a vibration mill, and a medium stirring mill is preferable. In these models, it is considered that the grinding is performed at the center of the grinding force and the shearing force, so that the corner can be ground. Wet grinding is also preferred, as is dry grinding. Examples of specific device names include a vibration mill and a ball mill manufactured by Chuo Kakoki Co., Ltd., a mechano mill manufactured by Okada Seiko Co., Ltd., and a dry / wet type manufactured by Kurimoto Iron Works Co., Ltd. And a medium stirring mill. Next, as a device capable of performing surface pulverization, as a processed material passes between a rotating container and a taper attached to the inside of the container, a compressive force caused by a speed difference between the rotating container and the taper is generated. A model in which a shear force is applied to the processed material is preferred. These devices are originally devices for compounding two or more kinds of powders and performing surface modification of the powders. However, since they are devices to which a shear force is strongly applied, the filling property of the powders is high. It is considered that the particles could be improved, that is, the particles could be rounded. As an example of specific equipment names, Theta Composer manufactured by Tokuju Kousaku Co., Ltd., Hosokawa Micron Corporation
And a mechanofusion system manufactured by the company.

The pulverization limit refers to a region of a particle diameter, and is a lowermost limit region as a particle diameter at which volume pulverization proceeds. That is, it is a particle diameter region where the particle diameter is reduced, the collision probability is reduced, and the particle's own weight is also reduced, so that a large stress is not generated even when the particles collide, and the volume pulverization does not progress. In this region, the surface pulverization is performed instead of the volume pulverization, and the filling property of the powder after the treatment improves only the filling property without largely changing the median diameter. To utilize this pulverization limit, a single pulverization process can be performed, but it is preferable that the pulverized material that has passed through the processing device is again fed into the processing device. Further, a device having a built-in classification mechanism is also preferable. It is more preferable to connect the classifying mechanism to the pulverization processing apparatus and circulate the processed material, since the pulverization is performed a plurality of times. The number of repetitions is 1
Or more times, more preferably 3 times or more, particularly preferably 4 times or more. A high-speed rotary mill is essentially a mechanical pulverizer that performs volume pulverization by combining impact force, compression force, and shear force. Preferred apparatus conditions are conditions that suppress the impact force and increase the shearing force, but by repeating the processing, the particle diameter region of the processed product reaches the apparatus-specific pulverization limit, and surface pulverization is mainly performed. become. Alternatively, the same effect can be reliably obtained even when the processing is performed for a long time using a batch-type processing apparatus, and this is further preferable.

As a result of diligent studies, the present inventors can proceed with surface pulverization even with a processing apparatus designed to promote volume pulverization as long as the pulverization limit is utilized. It has been found that it is possible to obtain treated products with improved filling properties. As such a process, it is preferable to use a high-speed rotary mill composed of a rotor that rotates at a high speed and a stator provided around the rotor. It is more preferable to operate the rotor at a low rotation speed so that a large impact force is not applied. Further, it is preferable that a plate-shaped blade is attached to the rotor for use, and a certain gap or more is provided in the gap between the rotor and the stator so that impact pulverization hardly occurs. As an example of a specific device name, a fine mill manufactured by Nippon Pneumatic Industries Co., Ltd., a turbo mill manufactured by Turbo Kogyo Co., Ltd., or the like may be used.

However, if the concept of the pulverization limit is used, the surface pulverization progresses, and a processed product having rounded corners and improved filling properties cannot be obtained with any type of apparatus. According to the Graphite section of the “Granular Particle Process Technology Collection” published by the Industrial Technology Center in 1974, graphite can easily be flattened if it is processed by a friction pulverization type. It is described that if energy-type pulverization is performed, friction between particles may increase, or particles having rounded shapes with sharp corners may be obtained. However, as a result of studies by the inventors, a fluid energy type pulverizer could not obtain a powder having a high filling property in the target particle diameter range of 5 to 50 μm. This is considered to be because the pulverizing power was too strong because the fluid energy type pulverizer employs the principle of pulverizing particles in a gas stream close to the speed of sound.

As a result of further studies by the present inventors, a mixing device having a specific structure is suitable as a surface pulverizing device as a device capable of continuously applying a shearing force to an object to be processed. I found something. As a mixing device having a specific structure, a processing chamber in which a plurality of plow-shaped or saw-tooth-shaped paddles fixed to the shaft and a plurality of puddles are arranged in different phases is provided. The wall is formed in a cylindrical shape along the outermost line of rotation of the paddle to minimize the gap, multiple paddles are arranged in the axial direction of the shaft, and the screw type disintegrator that rotates at high speed on the inner wall of the device A mixing device having a structure in which one or a plurality of crushing blades are provided in one or more stages can be given. The workpiece is subjected to a shearing force by the screw type crusher and, at the same time, receives a compressive force to the wall surface by the rotation of the paddle. The structure that applies the shearing force and the compressive force has a structure that matches the surface crushing mechanism that the present inventors consider preferable, despite being originally a mixer. As an example of a specific device name, a Reedige mixer manufactured by Matsuzaka Giken Co., Ltd., a Plowshare mixer manufactured by Taiheiyo Kiko Co., Ltd., and the like are exemplified.

When the true density of the carbonaceous powder before the treatment is less than 2.25 and the crystallinity is not so high, it is preferable to perform a heat treatment for increasing the crystallinity again after the above-mentioned mechanical energy treatment. Heat treatment is preferably 2000 ° C or higher,
More preferably 2500 ° C. or higher, most preferably 280 ° C.
It is better to carry out at 0 ° C. or higher.

The median diameter of the treated carbonaceous or graphitic powder obtained by the production method of the present invention is 5 to 50 μm.
m, preferably 10 to 50 μm, more preferably 10
２５25 μm, particularly preferably 15-25 μm. The amount of the fine powder having a particle size of 10 μm or less is 25% or less, preferably 17% or less, more preferably 14% or less, and still more preferably 12% or less in a volume-based particle size distribution. The BET specific surface area of the graphite particles after the treatment is as follows:
0.5 m ² / g or more and 25.0 m ² / g or less, preferably 2.0 m ² / g or more and 10.0 m ² / g or less, more preferably 3.0 m ² / g or more and 7.0 m ² / g. It is more preferably 3.5 m ² / g or more and 5.0 m ² / g or less. As a method for achieving both the particle diameter and the BET specific surface area, there is control of the specific surface area by a classification operation. By performing the fine powder removal by the classification operation, the specific surface area can be effectively reduced. In Raman spectrum analysis using argon ion laser light, 1580 to 1620 cm −1
PA (peak intensity IA) and 1350
Peak PB (peak intensity I
B) intensity ratio R = IB / IA of 0.0 or more and 0.7 or less,
The half width of the peak in the range of 1580 to 1620 cm ^-1 is 2
It is preferably 8 cm ⁻¹ or less. Further, the intensity ratio R of the Raman spectrum is more preferably 0.5 or less, and 0.3
The following are most preferred. Half width is more preferably 26cm ^-1 or less of a peak in the range of 1580~1620cm ^-1, 2
Most preferably 4 cm ^-1 or less. In addition, the average circularity for all particles (the ratio of the perimeter of a circle corresponding to the particle area as a numerator and the perimeter of the captured particle projection image as a denominator is 1 as the particle image is closer to a perfect circle, The smaller the particle image is, the smaller the value is when the particle image is elongated or uneven) is preferably 0.940 or more. Further, based on the particle size distribution based on the circle equivalent diameter, those having a 15 μm limited average circularity of 0.850 or more, which is a restriction so that only particles having a median diameter of 15 μm or more are targeted, are more preferable. The equivalent circle diameter is the diameter of a circle (equivalent circle) having the same projected area as the captured particle image, and the circularity is defined as the circumference of the equivalent circle as a numerator and the periphery of the captured particle projection image. This is the ratio with the length as the denominator.

The multi-layered carbon material of the present invention is obtained by mixing the carbonaceous or graphitic powder after the treatment with an organic compound to be carbonized in a firing step, and then firing the organic compound. The organic compounds to be mixed with the carbonaceous or graphitic powder include, as organic substances that promote carbonization in the liquid phase, coal tar pitch from soft pitch to hard pitch, coal-based heavy oil such as coal liquefied oil, asphaltene Petroleum heavy oils such as naphtha tar and other cracked heavy oils by-produced during thermal cracking of crude oil, naphtha, etc.
Heat-treated pitches such as ethylene tar pitch, FCC decant oil, and ashland pitch obtained by heat-treating cracked heavy oil can be used. Further, a vinyl polymer such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, and polyvinyl alcohol, and 3
-Methylphenol formaldehyde resin, substituted phenol resins such as 3,5-dimethylphenol formaldehyde resin, aromatic hydrocarbons such as acenaphthylene, decacyclene, anthracene, nitrogen ring compounds such as phenazine and acridine, and sulfur ring compounds such as thiophene Substances. Examples of the organic substance that progresses carbonization in the solid phase include natural polymers such as cellulose, chain vinyl resins such as polyvinylidene chloride and polyacrylonitrile, aromatic polymers such as polyphenylene, furfuryl alcohol resin, and phenol-formaldehyde. Examples thereof include thermosetting resins such as resins and imide resins, and thermosetting resin raw materials such as furfuryl alcohol. These organic substances can be used by adhering to the surface of the graphite particle nucleus by dissolving and diluting these organic substances, if necessary, by appropriately selecting a solvent.

In the present invention, usually, a mixture of such a carbonaceous or graphitic powder and an organic compound is heated to obtain an intermediate substance, which is then carbonized, fired and pulverized, so that carbon particles are finally added to the surface of the particles. A multi-layered carbonaceous powder having a surface layer of a carbonaceous material formed thereon is obtained. % By weight or more, more preferably 15% by weight or less, 1% by weight or more, particularly preferably 10% by weight or more.
It is adjusted so as to be 2% by weight or less by weight.

On the other hand, the production process for obtaining such a multi-layer carbonaceous material according to the present invention can be divided into the following four processes. First step: a step of mixing a carbonaceous or graphitic powder with an organic compound and, if necessary, a solvent using various commercially available mixers and kneaders to obtain a mixture. Second step: a step of heating the mixture while stirring, if necessary, to obtain an intermediate substance from which the solvent has been removed.

Third step: a step of heating the mixture or the intermediate substance to 500 ° C. or more and 3000 ° C. or less in an atmosphere of an inert gas such as a nitrogen gas, a carbon dioxide gas and an argon gas or a non-oxidizing atmosphere to obtain a carbonized material. . Fourth step: a step of subjecting the carbonized material to powder processing, such as pulverization, crushing, and classification, as necessary. Among these steps, the second step and the fourth step
The step can be omitted in some cases, and the fourth step is the third step.
It may be performed before the process.

The heat treatment conditions in the third step include:
Thermal history temperature conditions are important. The lower limit of the temperature is slightly different depending on the kind of the carbon precursor and its heat history, but it is usually 50.
0 ° C. or higher, preferably 700 ° C. or higher, more preferably 9 ° C.
It is 00 ° C or higher. On the other hand, the upper limit temperature can be raised to a temperature that does not basically have a structural order exceeding the crystal structure of the graphite particle nucleus. Therefore, the upper limit temperature of the heat treatment is usually 3000 ° C. or lower, preferably 2800 ° C. or lower, more preferably 2500 ° C. or lower, and particularly preferably 1500 ° C. or lower. Under such heat treatment conditions, the rate of temperature rise,
The cooling rate, heat treatment time, and the like can be arbitrarily set according to the purpose. After heat treatment in a relatively low temperature range,
The temperature can be raised to a predetermined temperature. The reactor used in this step may be a batch type or a continuous type, and may be a single unit or a plurality of units.

The multilayer carbon material of the present invention has a volume-based
A dian diameter of 5 to 70 μm, preferably 10 to 40 μm,
Particularly preferably, it is 15 to 30 μm. According to the present invention
Specific surface of multi-layered carbon material measured using BET method
The product is preferably 1 to 10 m2 / g, more preferably 1 to 10 m2 / g.
4m^Two/ G, particularly preferably 1-3 m^Two/ G range
Preferably, the carbonaceous material having a multilayer structure of the present invention
Has a wavelength of 5145 cm^-1Argon ion laser light
Raman spectrum analysis using CuKα radiation as the source
In the diffractogram of X-ray wide-angle diffraction, carbon
Does not exceed the crystallinity of the graphitic particles.
 The spectra and peaks are as follows unless otherwise specified.
It is a Raman spectrum according to conditions. That is, 158
0-1620cm^-1PA (peak intensity I
A) and 1350-1370 cm ^-1Peak P in the range
B (peak intensity IB). As specific numbers,
Preferably 0.01 or more, 1.0 or less, more preferably
0.05 or more, 0.8 or less, more preferably 0.1 or less
Above, it is 0.6 or less. Also, the apparent density is
More improved than the more used nuclear graphite material, but 0.7
It is desirable to control to a range of -1.2 g / cc. all
The average circularity for particles was 0.94 before the multilayer structure was formed.
Those which are larger than 0 are preferred. Furthermore, the circle equivalent diameter
Particles having a median diameter of 15 μm or more
15μm limited average with restriction to target only
The degree of circularity is also greater than 0.850 before the multilayer structure
Is more preferred. Multi-layer structuring is the core mechanical energy
And further improve the apparent density of
Has the effect of introducing further roundness.

[0043]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. (Measurement method) (1) Volume-based average particle size About 1 cc of a 2 vol% aqueous solution of polyoxyethylene (20) sorbitan monolaurate was used as a surfactant, and this was mixed with carbonaceous powder in advance, and then ion-exchanged water was used. Was used as a dispersion medium, and the volume-based average particle diameter (median diameter) was measured with a laser diffraction particle size distribution analyzer “LA-700” manufactured by Horiba, Ltd.

(2) Apparent Density (Tap Density) Using a powder density measuring device “Tap Denser KYT-3000” manufactured by Seishin Enterprise Co., Ltd., a sieve having a mesh size of 300 μm was used as a sieve through which the sample passes. The powder was dropped into a 20 cc tapping cell, and after the cell was completely filled, tapping with a stroke length of 10 mm was performed 1,000 times, and the apparent density at that time was measured. (3) Measurement of BET specific surface area Using AMS-8000 manufactured by Okura Riken Co., Ltd., it was heated to 350 ° C. as preliminary drying, nitrogen gas was flowed for 15 minutes, and then measured by the BET one-point method by nitrogen gas adsorption.

(4) Measurement of True Density Using a 0.1% aqueous solution of a surfactant, the true density was measured by a liquid phase replacement method using a pycnometer. (5) X-ray diffraction X-ray standard high-purity silicon powder of about 15% is added to and mixed with the sample, packed in a sample cell, and a CuKα ray monochromatized with a graphite monochromator is used as a radiation source, and a reflection type diffract is used. The wide-angle X-ray diffraction curve was measured by a meter method, and the interlayer distance (d002) and the crystallite size (Lc) were determined by the Gakushin method.

(6) Raman Measurement Using NR-1800 manufactured by JASCO Corporation, wavelength: 514.5 n
In Raman spectrum analysis using an argon ion laser beam of m, the intensity of the peak PA around the 1580 cm ^-1 IA, the intensity of the peak PB in the range of 1360 cm ^-1 I
B was measured, and the intensity ratio R = IB / IA was measured.
In preparing the sample, the cell was filled in a powder state by natural fall, and the measurement was performed by rotating the cell in a plane perpendicular to the laser light while irradiating the sample surface in the cell with the laser light.

(7) Measurement of circularity Flow particle image analyzer “FPIA-” manufactured by Toa Medical Electronics Co., Ltd.
Using "1000", the particle size distribution was measured by the equivalent circle diameter and the circularity was calculated. Ion exchange water is used as the dispersion medium, and polyoxyethylene (20) is used as the surfactant.
Sorbitan monolaurate was used. First, after calculating the average circularity for all the particles, based on the particle size distribution based on the equivalent circle diameter, a restriction is applied so that only particles having a median diameter of 15 μm or more are targeted, and the 15 μm limited average circularity is calculated. Was. The equivalent circle diameter is the diameter of a circle (equivalent circle) having the same projected area as the captured particle image, and the circularity is defined as the circumference of the equivalent circle as a numerator and the periphery of the captured particle projection image. This is the ratio with the length as the denominator.

(8) Measurement of Electric Capacity by Half-Battery 8-1) Preparation of Half-Battery A slurry is prepared by adding a thermoplastic elastomer to a carbonaceous material as a binder, and the slurry is applied on a copper foil by a doctor blade method to form a sheet electrode. Created. This electrode has a diameter of 15.
A coin cell was punched out into a 4 mm disk shape and made to face a lithium metal electrode around a separator impregnated with an electrolyte, and a charge / discharge test was performed. As the electrolyte, lithium perchlorate was added to a solvent obtained by mixing ethylene carbonate and diethyl carbonate at a weight ratio of 1: 1.
What was melt | dissolved at the ratio of 5 mol / l was used.

8-2) Measurement of Electric Capacity In the charge / discharge test, a current value was set to 0.2 mA, charging was performed until the potential difference between both electrodes became 0 V, and discharging was performed until the potential difference became 1.5 V. The capacitance to compare the crystallinity of carbonaceous materials includes:
The discharge capacity at the fifth cycle was used.

(Selection of raw materials before treatment) Raw materials before pulverization were selected by X-ray diffraction measurement, Raman spectroscopy, and electrochemical capacity. As a result, petroleum artificial graphite 2 with different particle size
Two kinds of natural graphite and one kind of petroleum coke made from Sri Lanka having different species and particle sizes were selected. Table 1 shows the raw materials used in the study.
Organized.

(Mechanical Energy Treatment) 1) Example 1 Using a research pot mill manufactured by Chuo Kakoki Co., Ltd.
A stainless steel ball having a diameter of 5 mm and a natural graphite powder A of 0.5 kg were charged into a 3.6-liter cylindrical grinding pot, and grinding treatment was performed at 80 rpm for 24 hours. Tables 2 and 3 show the results. 2) Example 2 Using a φ200 batch dry agitating mill manufactured by Kurimoto Ironworks Co., Ltd., crushing media of 2 mm diameter alumina balls and artificial graphite powder B (0.3 kg) were charged, and 480 r
The crushing treatment was performed at pm for 25 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.19,1580Cm ^-1 was 22.2cm ^-1. Other results are shown in Tables 2 and 3.

3) Example 3 T-400 type turbo mill (4J) manufactured by Turbo Kogyo Co., Ltd.
), Rotate the rotor at 3600 rpm,
The processed material was supplied at 150 kg / hr by a screw feeder and pulverized. The particle size of the collected pulverized material did not change significantly. In order to perform surface pulverization using the pulverization limit, the pulverized material was re-pulverized. The same processed material was processed a total of four times. Tables 2 and 3 show the results.
Shown in 4) Example 4 Using a M20 type Reedige mixer (20 liters in internal volume) manufactured by Matsubo Corporation, natural graphite powder B was 4.0 k.
g, a paddle for stirring was rotated at 230 rpm, and a chopper for crushing was rotated at 3000 rpm, and the mixture was stirred for 150 minutes. The ratio R value of Raman spectrum intensity is 0.22, 15
The half-value width of the peak in the vicinity of 80 cm ^-1 was 21.3 cm ^-1. Other results are shown in Tables 2 and 3.

5) Example 5 Using an FKM-130D model Reedige mixer (internal volume: 130 liters) manufactured by Matsubo Corporation, 50 kg of artificial graphite powder B was charged, and a paddle for stirring was set at 140 rpm.
Rotate the chopper for crushing at 3600 rpm, 30
Stirred for minutes. Raman spectrum intensity ratio R value is 0.2
The half width of the peak near 5, 1580 cm ^-1 is 21.8.
cm ^-1 . Other results are shown in Tables 2 and 3. 6) Example 6 The mixture was stirred for 60 minutes with the same raw material conditions as in Example 5. Tables 2 and 3 show the results.

7) Example 7 The same apparatus conditions as in Example 5 were used and the raw materials were stirred for 150 minutes.
Raman spectrum intensity ratio R value is 0.29, 1580c
m^-1Of the peak near is 22.4 cm ^-1So
Was. Other results are shown in Tables 2 and 3. 8) Example 8 The same equipment conditions and raw materials as in Example 5 were used to obtain Example 3.
The treatment was stirred for 90 minutes. Tables 2 and 3 show the results.
You.

9) Example 9 Using an AM-80F type mechanofusion system manufactured by Hosokawa Micron Co., Ltd. (having a grinding chamber diameter of 800 mm), 7 kg of artificial graphite powder A was charged, and the grinding chamber was rotated at 500 rpm.
m and run for 30 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.35,1580Cm ^-1 was 23.5cm ^-1. Other results are shown in Tables 2 and 3. 10) Example 10 Using an AM-80F mechanofusion system manufactured by Hosokawa Micron Co., Ltd. (diameter of grinding chamber: 800 mm), 7 kg of artificial graphite powder A was charged, and the grinding chamber was rotated at 500 rpm.
m and run for 30 minutes. The ratio R value of Raman spectrum intensity half width of the peak around the 0.27,1580Cm ^-1 was 22.3cm ^-1. Other results are shown in Tables 2 and 3.

11) Example 11 Using an AM-20FS mechanofusion system manufactured by Hosokawa Micron Corp. (pulverization chamber having a diameter of 200 mm), 30 g of artificial graphite powder B and 1 kg of ceramic balls having a diameter of 0.5 mm were charged. The grinding chamber was rotated at 450 rpm and operated for 30 minutes. Raman spectrum intensity ratio R
Value half width of a peak in the vicinity of 0.49,1580Cm ^-1 was 25.8cm ^-1. Other results are shown in Tables 2 and 3. 12) Example 12 30 g of petroleum coke and 1 kg of ceramic balls having a diameter of 0.5 mm were charged using an AM-20FS type mechanofusion system manufactured by Hosokawa Micron Corp. (diameter of a grinding chamber of 200 mm), and the grinding chamber was rotated at 450 rpm. And run for 30 minutes. Tables 2 and 3 show the results.

13) Example 13 Theta Composer (manufactured by Tokuju Kousaku Co., Ltd.)
0L), 10 kg of artificial graphite B was charged, the vessel was rotated at 20 rpm, the rotor was rotated at 400 rpm, and the apparatus was operated for 30 minutes. Tables 2 and 3 show the results. 14) Example 14 4 kg of the processed product obtained in Example 2 and 1 kg of petroleum-based tar
Were mixed in a batch kneader having a sigma type blade. Subsequently, the temperature was raised to 700 ° C. in a nitrogen atmosphere,
A tar removal treatment was performed, followed by a heat treatment to 1200 ° C. The obtained heat-treated product was pulverized with a pin mill, and subjected to a classification treatment for the purpose of removing coarse particles, thereby finally obtaining carbonaceous material particles having a multilayer structure. Table 4 shows the results.

15) Example 15 The same treatment as in Example 13 was performed using the processed product obtained in Example 3. Table 4 shows the results. 16) Example 16 The same treatment as in Example 13 was performed using the processed product obtained in Example 4. Table 4 shows the results.

17) Example 17 3 kg of the treated product obtained in Example 5 and 7 kg of petroleum-based tar
Were mixed in a batch kneader having a sigma type blade. Subsequently, the temperature was raised to 700 ° C. in a nitrogen atmosphere,
A tar removal treatment was performed, followed by a heat treatment to 1200 ° C. The obtained heat-treated product was pulverized with a pin mill, and subjected to a classification treatment for the purpose of removing coarse particles, thereby finally obtaining carbonaceous material particles having a multilayer structure. Table 4 shows the results. 18) Comparative Example 1 KTM0Z type Kryptron manufactured by Kawasaki Heavy Industries, Ltd. was used, artificial graphite powder A was supplied at 17 kg / hr, and the rotor was rotated at 9000 rpm for operation. Table 2 shows the results
And Table 3 below.

19) Comparative Example 2 Using an FM-300S type fine mill manufactured by Nippon Pneumatic Industries, artificial graphite powder A was supplied at 40 kg / hr, and the rotor was rotated at 3000 rpm for operation.
Tables 2 and 3 show the results. 20) Comparative Example 3 T-400 type turbo mill (4J) manufactured by Turbo Kogyo Co., Ltd.
), Rotate the rotor at 3600 rpm,
The processed material was supplied at 150 kg / hr by a screw feeder and pulverized. Tables 2 and 3 show the results.

21) Comparative Example 4 Using an ACM Pulperizer Model 10 manufactured by Hosokawa Micron Co., Ltd., artificial graphite powder B was supplied at 50 kg / hr, and the pulverizing blade was rotated at 7000 rpm to perform the treatment. Tables 2 and 3 show the results. 22) Comparative Example 5 Artificial graphite powder B was supplied at 190 kg / hr using an INM-30 type inomizer manufactured by Hosokawa Micron Corp., and the pulverizing blade was rotated at 5000 rpm to perform the treatment. Tables 2 and 3 show the results.

23) Comparative Example 6 IDS-2UR type impact plate type manufactured by Nippon Pneumatic Industries, Ltd.
30kg / hr of artificial graphite powder B using jet mill
And pulverized. Raman spectrum intensity ratio R
The value is 0.81, 1580 cm^-1Half width of the peak near
Is 28.2cm ^-1Met. Table 2 and Table 2 show other results
3 is shown. 24) Comparative Example 7 Counter Jet Mill 2 manufactured by Hosokawa Micron Corporation
Uses 00AFG (fluid bed type, pulverized by powder-powder contact)
Then, artificial graphite powder A was supplied at a rate of 75 kg / hr and pulverized.
Was. Raman spectrum intensity ratio R value is 0.67,15
80cm^-1Of the peak near is 26.5 cm^-1so
there were. Other results are shown in Tables 2 and 3.

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[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

[0066]

[Table 4]

[0067]

According to the production method of the present invention, a dense carbonaceous powder exhibiting a high filling property necessary for improving the filling property can be obtained in applications requiring a high-density molded body. .

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiromi Fujii 3-1-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Prefecture Inside the Tsukuba Research Laboratory, Mitsubishi Chemical Corporation (72) Inventor Takashi Kameda 8-Chome, Ami-cho, Inashiki-gun, Ibaraki Prefecture No.3-1 Inside the Tsukuba Research Laboratory, Mitsubishi Chemical Corporation

Claims (4)

[Claims] 1. A highly-filled carbonaceous material characterized in that by applying mechanical energy to a carbonaceous powder, the apparent density ratio before and after treatment is 1.1 or more and the median diameter ratio before and after treatment is 1 or less. Powder manufacturing method. 2. An interlayer distance (d00) of a carbonaceous powder before treatment.
2) is 0.345 nm or less, and the crystallite size (Lc) is 1
The method for producing a carbonaceous powder according to claim 1, wherein the thickness is 0 nm or more. 3. The highly-filled carbonaceous powder after treatment has a median diameter of 5 to 50 μm and a BET specific surface area of 25 μm.
^{3. The} method for producing a carbonaceous powder according to claim 1, wherein the carbonaceous powder is at most m ² / g. 4. A highly-filled, multi-layered carbonaceous powder, comprising mixing the highly-filled carbonaceous powder after the treatment according to claim 1 with an organic compound, and then carbonizing the organic compound. Manufacturing method.