WO2006109497A1 - Process for production of mesocarbon microbeads - Google Patents

Abstract

A process for producing in a high yield mesocarbon microbeads which have a narrow particle size distribution, spherical shapes and smooth surfaces, specifically, a process for the production of mesocarbon microbeads by heat-treating a mixture which comprises a carbonaceous component (1) and a carbonaceous component (2) having an aromaticity lower than that of the component (1) and which has an fa2/fa1 ratio of 0.95 or below wherein fa1 is the aromatic carbon fraction of the component (1) and fa2 is the aromatic carbon fraction of the component (2). The component (1) may be composed of one member selected from among coal tar and coal tar pitches, while the component (2) may be composed of ethylene bottom oil, decanted oil, asphaltene, pitches prepared from them, or the like. The weight ratio of the component (1) to the component (2) may be 99/1 to 30/70.

Description

 Specification

 Method for producing mesocarbon microbeads

 Technical field

 The present invention relates to a method for producing mesocarbon microbeads (unfired and fired mesocarbon microbeads) useful for various carbon materials such as negative electrode materials for lithium secondary batteries and special carbon materials, mesocarbon microbeads, and The present invention relates to a negative electrode for a lithium secondary battery. Background art

 [0002] Carbon materials (or carbon powder materials) obtained by carbonizing (carbonizing or firing) carbon precursors such as mesocarbon microbeads (MCMB) are used in various applications, such as negative electrode active materials (for example, Lithium ion secondary battery negative electrode active material) and conductive fillers are used in various applications. In particular, lithium secondary batteries are attracting attention as small, lightweight, high-energy density lithium-ion secondary batteries as power sources for portable devices, and will continue to be applied to applications such as power sources mounted in automobiles and power storage. Demand growth is expected. In other words, MCMB that has been fired (graphitized) has a structure similar to graphite, and therefore can intercalate and desorb lithium ions and is used as a high-capacity negative electrode material for lithium secondary batteries. (J. Power Sources 43-44 (1993) 233-239 (Non-Patent Document 1), The Electrochemical Society Extended Abstracts, Vol. 93-1 (1 993) 8 (Non-Patent Document 2), Carbon Νο.165 (1994 ) 261-267 (Non-Patent Document 3)). Fired (black lead) treated MCMB (fired MCMB) has a good balance of performance such as discharge capacity, efficiency, rate characteristics, bulk density and low reactivity with electrolyte, but natural graphite or artificial black lead When used as a negative electrode material for lithium secondary batteries, which has a slightly lower crystallinity than the discharge capacity, the discharge capacity tends to be inferior. The firing capacity of such a fired MCMB increases to a certain extent as the firing temperature is increased. The increase in firing temperature is limited in terms of equipment and costs, and is practically used. There is a limit.

[0003] The characteristics as a carbon material (discharge capacity, reversible capacity, cycle characteristics, thermal stability, etc.) include the crystallinity, surface morphology, particle size, internal particle structure, and composition of the carbon material used. Depending on the carbon material, etc. There is growing interest in mesocarbon microbeads.

 Conventionally, mesocarbon microbeads have been produced by heating pitches to about 300 to 500 ° C. and separating and recovering the generated mesocarbon microbeads by means such as solvent fractionation. However, this method has a low production efficiency and the yield of MCMB obtained by separation is only about 10% of the weight of raw material tar. Moreover, the particle size of the obtained MCMB is not uniform and the surface smoothness is also lacking.

[0005] For example, Japanese Patent Publication No. 1-27968 (Patent Document 1) states that (i) coal tar is subjected to a temperature of 0.5 to 50 under conditions of a temperature of 300 to 500 ° C and a pressure of normal pressure to 20 kgZcm ² 'G. (Ii) a step of separating the solid content and the clarified liquid by centrifuging the obtained heat treatment reaction product at 150 to 450 ° C., and (iii) a step of washing the obtained solid content. A method for producing the carbon particulates provided is described. Japanese Patent Laid-Open No. 1-242691 (Patent Document 2) discloses a method for heat treating coal-based heavy oil, separating the produced crude mesocarbon microbeads, washing and purifying them, and drying them to obtain mesocarbon microbeads. It describes a method for producing mesocarbon microbeads by dispersing and classifying mesocarbon microbeads after drying with a force that does not cause destruction. However, in these methods, as described above, mesocarbon microbeads having a smooth particle surface cannot be obtained, and the yield is low.

[0006] Also, in Japanese Patent Publication No. 6-35581 (Patent Document 3), by applying heat treatment to a pitch, an optically anisotropic small sphere formed in the pitch grows and merges to form a Baltamesov. Aze is finely dispersed in a silicone oil bath in a temperature range of 60 ° C to 160 ° C higher than the temperature at which the bulk mesophase has a viscosity of 200 boise, and then cooled to solidify the differentiated mesophase to bulk bulk mesophase. Manufactures mesocarbon microbeads. However, even with this method, as described above, mesophase beads with a smooth surface cannot be obtained. In addition, once optically anisotropic microspheres (that is, mesocarbon-bon microbeads) produced once are combined by further heat treatment, precipitated and aggregated as a bulk mesophase, and the resulting noromesophase is isolated and pulverized. A pulverization process is required, and the number of processes increases and the manufacturing procedure becomes complicated. Furthermore, heat treatment of the pulverized bulk mesophase in a silicone oil bath, and then wash the silicone oil with alcohol, etc. Since it must be cleaned, waste liquid such as used silicone oil and alcohol used for cleaning is generated, which is disadvantageous in terms of cost and environment.

 [0007] Further, in Japanese Patent Publication No. 63-1241 (Patent Document 4), the pitches are heat-treated at 350 ° C. to 500 ° C. to produce mesocarbon spherules in the pitch. In the method for producing mesocarbon spherules for separating spheres, the pitch is heat-treated to produce mesocarbon spherules, and then hydrocarbon oil having a boiling point of 300 ° C to the heat treatment temperature is 1Z4 to the heat-treated product. Repeatedly adding more than twice the amount and heat-treating again to form mesocarbon spherules, and mesocarbons separated from the resulting pitches containing a large amount of mesocarbon spherules. It describes how to make small spheres. Also, in the examples of this document, a pitch with a pitch yield of 38% and a mesophase amount of 31% in the pitch was obtained, and the obtained mesocarbon was a sphere having a diameter of 20 to 150. Are listed. However, even the method of this document cannot obtain mesocarbon microbeads having a smooth surface. Further, since the pitches are heat-treated to generate mesocarbon spherules in the pitch, and then the hydrocarbon oil is added and heat-treated again, the process is complicated.

 [0008] As a method for suppressing aggregation or coalescence of mesocarbon microbeads, Japanese Patent No. 3 674623 (Patent Document 5) discloses a method for treating crude mesocarbon microbeads produced by heat-treating petroleum heavy oil. A method for coating a surface with a pitch component having a thickness of 0.1 to 1 μm is disclosed. However, not only can the MCMB surface be smoothed by the method of this document, but also when used as a negative electrode material for a lithium secondary battery, the primary QI component that reduces the discharge capacity and initial efficiency adheres to the MCMB surface. ing. As a method of reducing the amount of free carbon on the MCMB surface (primary QI content), the MC component a, β, and γ are adjusted to reduce volatilization and make the firing atmosphere a little oxidizing. In this method, the crystallinity of MCMB decreases due to acid soot, and the cohesive component increases to obtain an agglomerated MCMB. Therefore, spherical MCMB cannot be obtained.

[0009] Various methods for generating a mesophase by combining a carbonizable material such as coal-based pitch with other materials are known. For example, in Japanese Patent No. 2697482 (Patent Document 6), the pitch is hydrogenated and heat-treated so that the soft saddle point is in the range of 250 to 380 ° C. In addition, there is disclosed a method for manufacturing a pitch-based material in which the pitch is further refined and oxidized. This document describes that the hydrogenation treatment may be performed by mixing a solvent holding hydrogen that can be transferred in advance with the pitch. Specifically, for example, in Example 1, 170 parts by weight of petroleum-based FCC residual oil was mixed with 100 parts by weight of a coal-based pitch having a soft scoring point of 120 ° C, and hydrotreated at 420 ° C. It is described that a pitch-based material was obtained by heat-treating at 420 ° C and finely converting the heat-treated pitch to an average particle size of 10 µm and oxidizing it. However, in the method of this document, the product becomes a bulk mesophase, and spherical particles cannot be obtained. For this reason, it is difficult to increase the density as a carbon material, and the structure becomes non-uniform. In addition, it is difficult to obtain particles having a smooth surface because of pulverization. Furthermore, in order to obtain a granular form, a pulverization process and an oxidation process are required, which complicates the process and increases costs.

J. Anal. Appl. Prosis, Vol.68 / 69, (2003) (Non-Patent Document 4) includes a coal tar pitch for impregnation with a softening point SP of 95 ° C and an SP of 127 ° C. Petroleum pitch A—240 (“Energy & Fuels 1993, 7”, page 421, described as petroleum pitch with aromatic carbon fraction = 0.89) was mixed in a solid state, and the mixture was blown with nitrogen. A pitch with SP of 176 ° C or higher was synthesized by heat treatment, and the effects of mesophase formation and solid content (primary quinoline insoluble QI) in the initial stage were investigated. Reported the mesophase coalescence suppression effect of According to this document, the generated pitch is hydrogen-rich, so the mesophase phase and the isotropic phase may be easily separated by thermal filtration, and the mesophase pitch after separation may be different. It has been reported that plasticity can be expected and there is a possibility of improving impregnation. However, the softening point of the generated pitch is 176 ° C or higher, and it is practically difficult to efficiently separate the mesophase phase industrially by the method described in this document, and MCMB with almost no thermoplasticity is produced. Is not intended. Even if the product force obtained by the method of this document also separates the mesophase phase, spherical particles cannot be obtained. Further, primary quinoline insoluble matter adheres to the particle surface, and the surface cannot be smoothed. Therefore, when the particles obtained by such a method are used for negative electrode applications, characteristics such as discharge capacity are deteriorated. There is no report on crystallinity in this document. Furthermore, Japanese Patent Application Laid-Open No. 61-271392 (Patent Document 7) and Japanese Patent Application Laid-Open No. 61-215692 (Patent Document 8) disclose that after a hydrogenation treatment by mixing a petroleum-based pitch with a coal-based pitch and heat-treating it. In addition, a method for producing mesophase pitch for carbon fiber having a relatively high soft point, which is mostly a cassofet structure, by blowing a reduced pressure or an inert gas is disclosed. Japanese Examined Patent Publication No. 62-23084 (Patent Document 9) discloses that a substantially isotropic premesophase pitch can be produced by substantially the same method to improve spinnability and infusibilities. Has been. Both of these methods produce high soft saddle-point pitch, which occupies most of the mesophase or premesophase structure, and use high-softening point coal pitch as a raw material, and high-soft point oil pitch as a hydrogenating agent. It is used as After hydrogenation, the hydrogenating agent is removed by blowing a vacuum or an inert gas, and at the same time, the soft spot is improved. However, it is not assumed that the mesophase structure is separated, and it is difficult to separate the mesophase structure because the pitch is a high and soft point. In other words, in the methods described in these documents, the solid content (primary QI content) for making the mesophase spherical (inhibition of aggregation or coalescence of the mesophase) causes yarn breakage during spinning. It is removed in the middle and spherical particles cannot be formed. Furthermore, a technology that can improve the infusibilities by producing a mesophase pitch with a soft trough point of 280-308 ° C, in which the ethylene tar component reacts with the coal tar component, has been reported by a method similar to the above ( (Non-Patent Document 5, Abstracts of Annual Meeting of the Carbon Society of Japan, 17 times, (1990)) o For the same reason, it is not possible to obtain spherical and highly crystalline mesocarbon microbeads with high yield. Can not.

Patent Document 1: Japanese Patent Publication No. 27968 (Patents)

Patent Document 2: Japanese Patent Laid-Open No. 1 242691 (Claims)

Patent Document 3: Japanese Patent Publication No. 6-35581 (Claims)

Patent Document 4: Japanese Patent Publication No. 63-1241 (Claims, Examples)

Patent Document 5: Japanese Patent No. 3674623 (Claims)

Patent Document 6: Japanese Patent No. 2697482 (Claims, Examples)

Patent Document 7: Japanese Patent Application Laid-Open No. 61-271392 (Claims)

Patent Document 8: Japanese Patent Application Laid-Open No. 61-215692 (Claims) Patent Document 9: Japanese Examined Patent Publication No. 62-23084 (Claims)

 Non-Patent Document 1: Power Sources 43-44 (1993), pp. 233-239

 Non-Patent Document 2: The Electrochemical Society Extended Abstracts, Vol.93— 1 (1993), p.8

 Non-Patent Document 3: Carbon Νο.165 (1994), pp. 261-267

 Non-Patent Document 4: J. Anal. Appl. Prosis, Vol. 68/69, (2003) pp. 409-424

 Non-Patent Document 5: Annual Meeting of the Carbon Materials Society of Japan, 17th (1990), pp. 30-33

 Disclosure of the invention

 Problems to be solved by the invention

Accordingly, an object of the present invention is to provide a method for producing mesocarbon microbeads having a smooth surface.

Another object of the present invention is to provide a method capable of industrially producing mesocarbon microbeads having a smooth surface with high yield.

[0014] Still another object of the present invention is to provide a method for producing mesocarbon microbeads having a sharp particle size distribution and a smooth surface with high yield.

Another object of the present invention is to provide a crystalline high carbon material (fired mesocarbon microbeads) useful as a negative electrode active material for a lithium ion secondary battery.

 Means for solving the problem

 [0016] As a result of intensive studies to achieve the above-mentioned problems, the present inventors have determined that the carbonaceous component (1) capable of producing mesocarbon microbeads (hereinafter sometimes referred to as MCMB) is the carbonaceous component. (1) It was found that a mesocarbon microbead having a smooth surface (especially a true sphere) could be produced by heat treatment in the presence of a less aromatic carbonaceous component (2), and the present invention was completed. .

 That is, the present invention provides a heat treatment of a mixture of a carbonaceous component (1) capable of producing mesocarbon microbeads and a low-carbonaceous component (2) that is more aromatic than the carbonaceous component (1). This is a method for producing mesocarbon microbeads including at least the above process. This way! The aromatic carbon of the carbonaceous component (2) with respect to the aromatic carbon fraction f of the carbonaceous component (1)

 al

The ratio f / ί of the fraction f is 0.95 or less (eg 0.9 or less). The carbonaceous component (1) is , Coal tar and coal tar pitch force may be composed of at least one selected. Further, the carbonaceous component (1) may be a carbonaceous component having an f of about 0.9 to 0.99.

 al

 It may be a carbonaceous component in which the content of primary quinoline insoluble matter is about 1 to 7% by weight.

[0018] The carbonaceous component (2) may have a lower aromaticity than the carbonaceous component (1). For example, the carbonaceous component (2) may be hydrated, pitched or hydrogenated. It may consist of at least one selected from heavy oil. In particular, the carbonaceous component (2) may be composed of ethylene bottom oil, decantyl, wasphaltene, and at least one selected from pitch force using these as raw materials. In addition, the carbonaceous component (2) has a carbonaceous component of f = 0.55 to 0.85.

 a2

 The content ratio of the component (heptane-soluble component) that dissolves in heptane with respect to the mixed solvent containing heptane and dimethylformamide, which can be even if it is a fraction, in the ratio of the former Z latter (weight ratio) = iZi The carbonaceous component may be about% by weight. The carbonaceous component (1) and the carbonaceous component (2) may each have a soft saddle point of 60 ° C. or less.

[0019] In the method of the present invention, in the method of the present invention, the carbonaceous component (1) and the carbonaceous component (2

The ratio of the former Z and the latter (weight ratio) = 99Zl to 30Z70 may be sufficient.

[0020] Typically, in the above method, (i) carbonaceous component (1) force liquid at room temperature (for example, about 15 to 25 ° C), f = 0.93 to 0.97 and primary The quinoline insoluble content is

 al

 1 to 7% by weight of a carbonaceous component, (ii) the carbonaceous component (2) is liquid at room temperature and f

 a2

= 0.6-0.8, a carbonaceous component having a content of the heptane-soluble component of 2-30% by weight, (iii) f / ί is 0.9 or less, and (iv) carbon Of the carbonaceous component (1) and the carbonaceous component (2) a2 al

 The former Z latter (weight ratio) = 90Z10-45Z55 may be sufficient. The mixture may further contain a compatibilizing agent in order to improve the compatibility between the carbonaceous component (1) and the carbonaceous component (2).

[0021] The method may include at least a step of heat treatment as long as it includes a step of heat treatment. By such firing treatment, fired mesocarbon microbeads can be obtained. For example, in the above method, after the heat treatment, the generated mesocarbon mic mouth bead is separated from the heat treated product (or reaction product, simply product, etc.), and the separated mesocarbon microbead is fired. Processed and calcined mesocarbon You can get microbeads.

[0022] Mesocarbon microbeads (unfired and fired mesocarbon-bon microbeads) obtained by the method of the present invention are spherical particles having a smooth surface. Such mesocarbon microbeads (unfired mesocarbon microbeads) of the present invention have a wave number (for example, 3050 cm ^{_ 1} ) corresponding to the C—H stretching vibration of aromatic carbon in the infrared absorption spectrum. When the absorption intensity is Π and the absorption intensity of the wave number corresponding to C—H stretching vibration of aliphatic carbon (for example, 2920 cm— ¹ ) is 12, the IlZ (II +12) value is 0.5-0. It may be about 8. Further, when the mesocarbon microbeads are assumed to be spherical and the apparent specific surface area calculated by particle size force is S1, and the BET specific surface area is S2, the degree of unevenness represented by S2ZS1 is 1 to It may be about 5.

 [0023] The present invention also includes spherical calcined mesocarbon microbeads obtained by calcining (graphitizing) the mesocarbon microbeads. Such a calcined mesocarbon microbead may have a spherical shape and high crystallinity. For example, the value of the interplanar spacing d (002) may be about 0.3354-0. Such a calcined mesocarbon microbead (carbon material) is useful for various materials such as a negative electrode active material of a lithium ion secondary battery having high crystallinity. Therefore, the present invention also includes a negative electrode for a lithium secondary battery (and a lithium secondary battery including the negative electrode) formed of the fired mesocarbon microbeads. The invention's effect

 [0024] In the present invention, a mixture of a carbonaceous component capable of producing mesocarbon microbeads and a carbonaceous component having a lower aromaticity than the carbonaceous component is heat-treated, so that mesocarbon microbeads having a smooth surface are obtained. Can be manufactured. In the present invention, mesocarbon microbeads having a sharp particle size distribution and a smooth surface can be produced with high yield. Carbon materials obtained by carbonizing such mesocarbon microbeads (fired mesocarbon microbeads

) Is suitable as a raw material for various carbon materials with high crystallinity, for example, a negative electrode active material for lithium ion secondary batteries and special carbon materials such as electrodes for electric discharge machining, or as a conductive filler for plastics. Can be used.

 Brief Description of Drawings

FIG. 1 is an electron micrograph of unfired MCMB obtained in Example 3. FIG. 2 is an electron micrograph of unfired MCMB obtained in Example 4.

 FIG. 3 is an electron micrograph of unfired MCMB obtained in Comparative Example 2.

 Detailed Description of the Invention

 [0026] [Method for producing mesocarbon microbeads]

 In the method of the present invention, a carbonaceous component (1) capable of producing mesocarbon microbeads (MCMB) is obtained in the presence of a carbonaceous component (2) having a lower aromaticity than the carbonaceous component (1). Heat treatment produces mesocarbon microbeads.

 [0027] (Carbonaceous component capable of producing mesocarbon microbeads (1))

As the carbonaceous component (1), any material capable of producing mesocarbon microbeads and capable of being carbonized (or graphitized) may be used. For example, aromatic compounds such as phthalene, azulene, indanthene, fluorene, phenanthrene, Two or more condensed polycyclic hydrocarbons such as anthracene, triphenylene, pyrene, taricene, naphthacene, picene, perylene, pentaphen, and pentacene; indole, isoindole, quinoline, isoquinoline, quinoxane, carbazole, atalidine, phenazine, A condensed heterocyclic compound in which a heterocyclic ring having 3 or more members such as phenanthridine and an aromatic hydrocarbon ring are condensed; anthracene oil, decrystallized anthracene oil, naphthalene oil, methylnaphthalene oil, tar (or Coal tar), creosote oil, carboru oil, solvent naphtha, etc. Aromatic oils), resin (for example, phenol resin, polyacrylo-tolyl resin, polysalt resin, etc.), pitches (for example, coal-based pitch (coal tar pitch), petroleum-based pitch), Examples include coatas. The pitch is a component obtained by removing low-boiling components having a boiling point of less than 200 ° C by subjecting petroleum-based or coal-based heavy oil such as petroleum distillation residue, coal liquefied oil, coal tar, etc. to distillation operation!ヽ Specifically, coal tar pitch can be cited as a representative. These carbonaceous components (1) may have a substituent, for example, an alkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, and the like. In addition, the carbonaceous component (1) is usually hydrogenated as the carbonaceous component (1) from the viewpoint of using a highly aromatic component that may be hydrogenated. In many cases, ingredients are used. A ring assembly compound (such as a ring assembly hydrocarbon such as biphenyl or binaphthalene) may be used, and the ring assembly compound and the carbonaceous component (1) may be used in combination. Carbonaceous component (1) may be used alone or in combination of two or more Can be used in combination.

 [0028] Among the carbonaceous components (1), a carbonaceous component having a low low boiling point and low molecular weight non-aromatic hydrocarbon component (for example, an aliphatic or alicyclic hydrocarbon component). Is preferred. For example, as such a carbonaceous component (1), from the viewpoint of cost and availability, heavy oil (especially non-hydrogenated coal-based heavy oil such as coal tar), pitches (particularly, And non-hydrogenated pitches such as coal tar pitch). The carbonaceous component (1) may be a component that has been previously heat-treated (eg, heat-treated at about 300 to 500 ° C.), but is usually a carbonaceous component (1) that has not been heat-treated. There are many cases.

 [0029] The carbonaceous component (1) may contain a primary QI component (quinoline insoluble component). The content of such primary quinoline insoluble component (sometimes referred to as primary QI) is: For example, 0.1 to 7% by weight (for example, about 0.3 to 6.5% by weight) of the total carbonaceous component (1), preferably 0.8 to 4.5% by weight, and more preferably 1 to 4%. It may be about 1% to 7% by weight (for example, about 1.5 to 6.5% by weight, preferably about 1.8 to 6% by weight). As will be described later, the primary quinoline insoluble matter contributes to the spheres of MCMB produced, while preventing MCMB from crystallizing and suppressing the aggregation (or coalescence) of MCMB. It is preferable to be contained in a moderate amount.

 [0030] Further, as described above, the carbonaceous component (1) is preferably a component having a low content of non-aromatic components. In particular, the content of an aliphatic component (for example, an aliphatic or alicyclic hydrocarbon component) is a component that is soluble in heptane (a component that is soluble in heptane or a component that is soluble in heptane, a component that is soluble in heptane). For example, the content (HS) of the heptane-soluble component to the total carbonaceous component (1) is, for example, 5% by weight or less (for example, 0 or the detection limit to about 4% by weight) It may be 3% by weight or less (for example, about 0 to 2.5% by weight), and more preferably 2% by weight or less (for example, about 0 to 1.8% by weight). The heptane-soluble component can be a component that is soluble in heptane with respect to a mixed solvent containing heptane and dimethylformamide at a ratio of the former Z latter (weight ratio) = 1Z1.

[0031] The soft spot (SP) of the carbonaceous component (1) can be selected from a range force of 80 ° C or less (about -80 ° C to 75 ° C), for example, 70 ° C or less (for example, — 50 ~ 65 ° C), preferably 60 ° C or less (eg 30 ° C to 55 ° C), more preferably 50 ° C or less (eg, about 10 ° C to 45 ° C), particularly 40 ° C or less (eg, about 0 to 35 ° C). It may be less than 30 ° C (eg, 20 ° C ~ 20 ° C)! /.

 [0032] In addition, the carbonaceous component (1) may be solid or liquid (liquid) at room temperature (for example, about 15 to 25 ° C). The carbonaceous component (1) is particularly liquid at room temperature or room temperature (for example, about 15 to 25 ° C.) since it is preferably liquid at the temperature at the time of separation and collection (for example, filtration temperature). Is preferred. The liquid carbonaceous component (1) may be viscous (viscous material) as long as it has fluidity at room temperature.

 [0033] By using such a low softening point or liquid carbonaceous component (1), separation of MCMB from the reaction product can be facilitated, and uniform MCMB in particle size, surface condition, etc. can be efficiently obtained. Obtainable. In other words, the soft point of the reaction system (or the reaction product of the carbonaceous component (1) and the carbonaceous component (2)) is raised by the heat treatment above the soft point of each component. Increasing the point not only reduces the separation or recovery efficiency of MCMB from the reaction product, but also reduces the smoothness of the MCMB particle surface. However, by using the low-soft point carbonaceous component (1) (and the low-soft point carbonaceous component (2)) as described above, the soft point of the reaction product is reduced. Since MCMB can be produced without extremely high (eg, 95 ° C or higher, especially 130 ° C or higher), separation or recovery efficiency can be improved. Note that by increasing the pressure during heat treatment, the volatile matter and decomposition products during the reaction can be incorporated into the reaction system, and the rise of the soft spot of the reaction product can be suppressed to some extent. Is not only efficient and leads to cost increase, but also the surface condition of the obtained MCMB cannot be improved.

 [0034] The aromatic carbon fraction (ratio of aromatic carbon atoms) f of the carbonaceous component (1) is usually 0.6.

 al

 5 to 0.99 (e.g., 0.7 to 0.98), preferably 0.75 to 0.98, more preferably 0.78 to 0.98 (f row, 0.8 to 0 97) Maybe! / Normally, f ί, 0.85 or more (f row, ί, 0

 al

A range force of about 88 to 0.995 can be selected, for example, 0.9 or more (for example, about 0.91 to 0.99), preferably 0.92 or more (for example, 0.93 to 0.98). Degree), more preferably 0.93 to 0.97, and usually 0.9 to 0.99. [0035] It should be noted that the aromatic carbon fraction is the carbon atom [aromatic carbon and non-aromatic carbon (for example, aliphatic carbon (particularly alicyclic carbon, linear or branched aliphatic carbon such as alicyclic carbon, alkyl group, etc. Etc.) expressed as the abundance ratio of aromatic carbon to the sum of eg)]]. Specifically, for example, NMR ^ vector (for example, ¹³ C NMR ^ vector) is measured using the carbonaceous component used as a sample, and the aromatic carbon area intensity (p) and non-aromatic in the obtained spectrum are measured. Carbon face

 a

 You may obtain | require from ratio with product intensity | strength (p). That is, when calculated by NMR measurement, aromatic

 f

 The carbon fraction (f) is expressed by the following equation.

 a

 [0036] f = p / (p + p)

 a a a f

 (Where f is the aromatic carbon fraction, p is the aromatic carbon area intensity, and p is the non-aromatic carbon a a f area intensity).

 [0037] (Low aromaticity !, carbonaceous component (2))

 The carbonaceous component (2) as a whole should have a lower aromaticity than the carbonaceous component (1) (specifically, it should have a lower aromatic carbon fraction), for example: (i) a relatively aromatic (Ii) Relatively low-aromatic carbonaceous components and high-aromatic carbonaceous components may be used. The mixture may be a carbonaceous component having a low aromaticity as a whole as a mixture. In the present invention, from the viewpoint of reducing aromaticity, a carbonaceous component that has been hydrogenated (or hydrotreated or hydrogenated) can be suitably used as the carbonaceous component (2).

 [0038] As the specific carbonaceous component (2), for example, a relatively low molecular weight component [for example, the above-described carbonizable component such as anthracene or a hydride thereof] is hydrogenated! However, heavy oil [petroleum heavy oil (petroleum distillation residue such as asphaltene, cracked heavy oil (ethylene bottom oil, decant oil), etc.), coal heavy oil (coal liquefied oil, coal tar, etc.) and These hydrides, etc.], and pitches that may be hydrogenated [petroleum pitch, ethylene bottom oil pitch, coal pitch (coal tar pitch, etc.), and hydrides thereof]. These components may be used alone or in combination of two or more. For example, a combination of heavy oil and hydride of heavy oil can be combined with hydrogen V, or can be combined with heavy oil or combined with pitch! /.

[0039] Preferred carbonaceous component (2) includes a heavy oil that may be hydrogenated [for example, hydrogenated Coal tar (hydride of coal tar), heavy petroleum oils (especially ethylene bottom oil), etc., pitches that may be hydrogenated (especially hydrides of coal tar pitch), etc. . Particularly preferred carbonaceous components (2) include ethylene bottom oil, decant oil, and waxartene, and pitches using these as raw materials, and ethylene bottom oil, among others.

 [0040] Incidentally, the carbonaceous component (2) contains a primary QI component (primary quinoline insoluble component)! /. However, the viewpoint of low aromaticity also substantially reduces the primary QI component. Including! / A carbonaceous component (2) is preferred. The content ratio (primary QI) of the primary QI component (primary quinoline insoluble component) is, for example, 0.2% by weight or less of the total carbonaceous component (2) (for example, 0 or detection limit to 0.2% by weight), It may be preferably 0.1% by weight or less (for example, 0 to 0.1% by weight), particularly 0.05% by weight or less (for example, 0 to 0.05% by weight). Prior to the heat treatment, the primary QI content may be removed from the carbonaceous component (2) by means such as filtration.

[0041] The carbonaceous component (2) usually contains an aliphatic component (for example, an aliphatic or alicyclic hydrocarbon component). Similar to the above, the content of such an aliphatic component has a correlation with the heptane-soluble content, and the content ratio HS of the heptane-soluble content can be used as a guide for the content of the aliphatic component. For example, the content ratio (HS) of the entire carbonaceous component (2) soluble in heptane (HS) can be selected from the range of about 0.5 to 50% by weight, and 1 to 40% by weight (for example, 2 to 35% by weight) ), Preferably 3 to 30% by weight, more preferably about 4 to 25% by weight, and usually about 2 to 30% by weight. As described above, the heptane-soluble component can be a component that is soluble in heptane with respect to a mixed solvent containing heptane and dimethylformamide at a ratio of the former Z latter (weight ratio) = 1Z1. If the carbonaceous component (2) (or mixture) contains an appropriate aliphatic component, it will be combined with the primary quinoline insoluble matter (particularly the primary quinoline insoluble matter in the carbonaceous component (1)) (or In combination, MCMB aggregation (or coalescence) can be efficiently suppressed. For this reason, MCMB generally cannot maintain a spherical shape as the particle size increases, and tends to become a balta shape or a pulverized shape (or a crushed shape) in which the balta shape is pulverized, but the aliphatic component is moderately contained. If it is included, the particle surface can be smoothed while preventing the primary QI from adhering to the particle surface, and spherical MCMB can be obtained efficiently even when the particle size is increased. HS is aromatic charcoal There is a certain correlation with the fraction fa, and if fa exceeds about 0.8, there are many cases where almost no aliphatic components are present in the carbonaceous component. For example, FCC decant oil is composed of aromatic (aromatic) molecules with an aromatic carbon fraction of about 0.8 and saturated (aliphatic) molecules with an aromatic carbon fraction of 0. It is described that there is almost no aliphatic component when the fraction is 0.8 or more (Carbon Glossary of Terms, Carbon Materials Society of Japan, Ryogune Jofusha, p. 30).

[0042] In addition, the aliphatic component reduces the viscosity or softening point of the reaction product and has the effect of improving the dispersibility of the primary QI in the reaction product. It has the effect of promoting the precipitation of the resulting quinoline-insoluble matter (or secondary QI content, ie, aromatic molecules that are larger than the primary QI content). Therefore, in the reaction product, the primary QI component can be prevented from adhering to the generated MCMB surface, and the primary QI component of the reaction product force and the separation of MCMB can be improved, and the primary QI component contained in MCMB (small The content of (particles with a particle size) can be reduced and the arrangement can be facilitated, so that the degree of crystallization of the fired MCMB can be improved.

 [0043] The aromatic carbon fraction f of the carbonaceous component (2) can be selected from the range of 0.5 to 0.9, for example

 a2

 0.5 to 0.85, preferably 0.6 to 0.82, more preferably 0.6 to 0.8, specially 0.6 to 0.78 (e.g. 0.7 It may be about .about.0.77), but usually about 0.6 to 0.8. f

 If a2 is too large, the hydrogenation capacity of the carbonaceous component (1) may not be sufficient as described later.

 If a2 is too small, the proportion of aliphatic components will increase and carbonaceous components (

There is a possibility that the compatibility with 1) is lowered, and as a result, the carbonaceous component (1) cannot be sufficiently hydrogenated.

 [0044] The ratio of the aromatic carbon fraction of the carbonaceous component (2) to the aromatic carbon fraction of the carbonaceous component (1) (f / ί) is, for example, 0.95 or less (eg, 0.4 to 0.95), for example a2 al

 0.5 to 0.9 (e.g. 0.5 to 0.88), preferably 0.6 to 0.85, more preferably 0.63 to 0.82, especially 0.65 to 0.81. It may be a degree, and may normally be from 0.61 to 0.86. If f / ί is too large, the hydrogenation capacity of the carbonaceous component (1) will decrease, and a2 al

 Thus, the precipitation effect of secondary QI due to the aliphatic component is also reduced. F / ί is too small

 a2 al

As a result, the compatibility between the carbonaceous component (1) and the carbonaceous component (2) decreases, and sludge is generated. The sludge is mixed into the MB, phase separation occurs due to the large specific gravity difference, uniform mixing and uniform reaction become difficult, aliphatic components are decomposed and gummed during heat treatment, and further In subsequent firing, fusion of MCMB tends to occur, which is not preferable. The presence or absence of sludge can be confirmed using a mixture of carbonaceous component (1) and carbonaceous component (2). It should be noted that whether hydrogen has sufficiently transferred from the carbonaceous component (2) to the carbonaceous component (1) depends on the carbonaceous component (1) alone and the carbonaceous component (1) and the carbonaceous component ( It can be roughly evaluated by comparing the aromatic carbon fraction in the produced MCMB with the case of using 2). MCMB aromatic carbon fraction when using carbonaceous components (1) and (2) is sufficiently higher than MCMB aromatic carbon fraction when using only carbonaceous component (1). If it is small, it indicates that hydrogen has been transferred sufficiently, and if there is not much change, it indicates that hydrogen has not transferred sufficiently. Since MCMB is a solid, unlike the carbonaceous component (1), the aromatic carbon fraction f depends on the measurement method using solids such as IR.

 You may ask for a.

 [0045] The soft spot (SP) of the carbonaceous component (2) is preferably relatively low like the carbonaceous component (1). For example, 80 ° C or less [eg, 100 ° C to 75 ° C, preferably 70 ° C or less (eg, about 70 to 65 ° C)], preferably 60 ° C or less (eg, about 50 ° C to 55 ° C), and more preferably 50 ° C or less ( For example, about 30 ° C to 45 ° C), especially 40 ° C or less (eg — about 20 ° C to 35 ° C), usually 30 ° C or less (eg, 40 ° C to 20 ° C degree).

 [0046] Further, the carbonaceous component (2) may be solid or liquid (liquid) at room temperature! /, Force Normal temperature or room temperature (for example, about 15 to 25 ° C) ) Is preferably liquid. The liquid carbonaceous component (2) may be viscous (viscous) as long as it has fluidity at room temperature. If the carbonaceous component (2) (and both of the carbonaceous component (1)) is liquid, the compatibility between the carbonaceous component (1) and the carbonaceous component (2) can be further improved.

 [0047] Also, the aromatic carbon fraction f & 丄 of the carbonaceous component (1) and the aromatic carbon fraction f & 丄 of the carbonaceous component (2)

 Difference (f f) is, for example, 0.05-0.4, preferably 0.1-0.35, more preferably

2 al a2

 ίma 0.15 ~ 0.33, especially 0.18 ~ 0.3!

In the present invention, the carbonaceous component (1) capable of generating mesocarbon microbeads and the carbon A mesocarbon microbead having a smooth surface can be obtained by heat-treating a mixture of the carbonaceous component (2), which is more aromatic than the carbonaceous component (1). Although the reason (principle) of generating mesocarbon microbeads with a smooth surface by the method of the present invention is not clear, hydrogen ((2) is converted from aromatic low carbonaceous component (2) to carbonaceous component (1). The transition of active hydrogen) effectively suppresses the increase in viscosity in the reaction system due to heat treatment, and as a result, promotes the development and generation of highly crystalline mesocarbon microbeads with smooth surfaces. It is The primary QI is also considered to be hydrogenated. In addition, since the viscosity in the reaction system is effectively reduced and the carbonaceous component (2) is heat-treated while covering the carbonaceous component (1), it is spherical (almost spherical) and has a narrow particle size distribution. Carbon microbeads can be obtained efficiently. That is, by mixing the carbonaceous component (1) with a carbonaceous component (2) (for example, heavy oil, pitch, etc.) that is less aromatic than the carbonaceous component (1), the system can be reduced. Viscosity can be changed, and the carbonaceous component (2) is interposed between the produced MCMB particles, so that aggregation of MCMB particles can be efficiently suppressed or prevented.

 [0049] In the mixture, the ratio of the carbonaceous component (1) and the carbonaceous component (2) is, for example, the former Z the latter (weight ratio) = 99Zl to 30Z70, preferably 95 to 5 to 35 to 65, more preferably 90 / 10 ~ 40/60, special [this may be around 90/10 ~ 45/55! / ヽ. The yield of mesocarbon microbeads increases as the proportion of the carbonaceous component (1) decreases, and conversely, the yield tends to decrease as the proportion of the carbonaceous component (1) increases. Therefore, the yield of mesocarbon microbeads can be controlled by changing the weight ratio of the carbonaceous component (1) and the carbonaceous component (2). If the proportion of the carbonaceous component (2) is too small, the mixing effect will be small, and if it is too large, the MCMB produced may be too large.

[0050] The mixture may contain a compatibilizing agent as necessary in order to improve the compatibility between the carbonaceous component (1) and the carbonaceous component (2). Examples of the compatibilizer include aromatic compounds having an aliphatic hydrocarbon group (for example, alkylenes such as methylnaphthalene), aromatic compounds containing a hetero atom such as a nitrogen atom, a sulfur atom, and an oxygen atom ( For example, quinoline, N-methyl-2-pyrrolidone, etc.). These compatible agents may be used alone or in combination of two or more. The ratio of the compatibilizer may be, for example, about 1 to: LO wt% with respect to the entire mixture. In addition, compatibility with the compatibilizer The upper effect can be enhanced as the soft spot of the carbonaceous component (1) and the carbonaceous component (2) is lowered.

 [0051] In the mixture, the content of primary quinoline-insoluble matter (sometimes referred to as primary QI or QA) is, for example, 0.05 to 6% by weight (for example, 0.1 to 5). % By weight), preferably 0.2 to 4% by weight, more preferably about 0.3 to 3% by weight, usually 0.4 to 3.5% by weight (eg 0.5 to 3%). (About weight%). The primary QI component has the effect of suppressing the aggregation or coalescence of the produced MCMB, and is usually contained at least in the carbonaceous component (1), and is particularly contained only in the carbonaceous component (1). It may be done. Also, if the heat treatment conditions are the same, if the amount of primary QI is large, the particle size of the produced MCMB tends to be small.

 [0052] The mixing of the carbonaceous component (1) and the carbonaceous component (2) (and optionally a compatibilizer) can be performed by a conventional method, and in particular, both components are further mixed. In order to ensure compatibility, both components are preferably mixed in liquid form rather than in solid form. That is, the mixture is preferably prepared by mixing the liquid carbonaceous component (1) and the liquid carbonaceous component (2). In order to mix the carbonaceous component (1) and the carbonaceous component (2) which can be mixed under heating (for example, about 70 ° C) more uniformly, stirring (using a stirrer) Mixing may be performed using agitation (circulation using a pump), vibration (vibration using ultrasonic waves, etc.), circulation (circulation using a pump, etc.).

[0053] The heat treatment of the mixture of the carbonaceous component (1) and the carbonaceous component (2), which is less aromatic than the carbonaceous component (1), is usually performed at a temperature of 300 to 500 ° C. when performed multi ingredients preferably ί or three hundred twenty to four hundred eighty ^o C, more [this preferably ί or 340-460 ^o C, may be performed in the range of about JP - this 350 to 450 ^o C. When the heat treatment temperature is less than 300 ° C, the formation of mesocarbon microbeads is not sufficiently achieved, while when the heat treatment temperature exceeds 500 ° C, the heat resistance of the reaction vessel or the plant is improved. It may be difficult to maintain stability and the like, and may lack industrial practicality.

 [0054] The reaction system during the heat treatment may be depressurized, normal pressure, or pressurized.

Usually, the reaction system is often pressurized. For example, the pressure in the system under pressure is about 0.15 to about LOMPa, preferably about 0.2 to 8 MPa, more preferably about 0.25 to 6MPa, special It may be about 0.3 to 5 MPa. When heat treatment is performed under pressure, volatile components in the mixture can be prevented from distilling out of the reaction system, and an increase in the softening point of the reaction product can be suppressed.

[0055] The heat treatment time can be appropriately selected in consideration of the type of raw material to be used, the heat treatment temperature, etc., and a time sufficient for the production of mesocarbon microbeads, for example, 1 to: LOO time, preferably May be 2 to 50 hours, more preferably 3 to 30 hours, particularly preferably about 5 to 20 hours.

 [0056] At the time of heat treatment, as long as the desired mesocarbon microbeads are produced, substitution in the reaction system with an inert gas may not be performed, but side reactions are suppressed and the produced mesocarbon microbeads are suppressed. In order to increase the carbon content of the beads, it is preferable to use an inert gas (nitrogen, helium, argon gas, etc.) atmosphere.

 [0057] The reaction may be batch-type, semi-batch-type, continuous-type! /, Or deviation! /.

[0058] The mixture after heat treatment (heat treatment product, reaction mixture, reaction product) contains quinoline insoluble matter produced by the reaction. The quinoline insoluble matter produced by such a reaction is called the secondary quinoline insoluble matter (secondary QI fraction), which is produced in contrast to the quinoline insoluble matter (primary quinoline insoluble fraction, primary QI fraction) contained in the raw material. It consists of mesocarbon microbeads. The content ratio of quinoline insoluble matter (secondary quinoline content) generated by such heat treatment, that is, the content ratio of secondary quinoline insoluble matter (secondary QI or A QI) increases with the progress of heat treatment. An increase in secondary QI indicates that the particles are agglomerated or coalesced and the particle size increases. Such secondary quinoline insoluble content (secondary QI, A QI) is, for example, 3 to 30% by weight, preferably 5 to 25% by weight, more preferably 8 to It may be about 20% by weight (for example, 10 to 15% by weight).

In addition, ΔQI can be obtained by (QI X reaction yield of reaction product) (primary QI).

[0060] The ratio of Δ QI (content ratio of quinoline insoluble matter produced by heat treatment) to primary QI (QI of the entire mixture before heat treatment) (ie, A QIZ—order QI) is, for example, 0.5 -20, preferably 1-18, more preferably 2-15 (eg, 2.5-14), especially around 3-12. The above ratio is correlated with the average particle size of MCMB and is often roughly proportional. Primary QI can be adjusted at the raw material stage and A QI can be adjusted by heat treatment conditions. However, even if these are changed, the relationship between A QI / -order QI and average particle size is almost the same. Therefore, on If the ratio is too small, the particle size of MCMB may be reduced and productivity may be reduced. If the ratio is too large, the MCMB particle size may be too large.

[0061] In the reaction product, the softening point (or viscosity) of the mixture is increased by the reaction. Such an increase in the soft spot or viscosity is preferably adjusted to be as low as possible from the viewpoint of enhancing the separability of the produced MCMB. For example, the soft spot (SP) of the reaction product can be selected as a range force of 150 ° C or less, for example, 130 ° C or less (eg, about 30 to 120 ° C), preferably 110 ° C or less (eg, , About 50 to 100 ° C.), more preferably 95 ° C. or less (eg, about 60 to 90 ° C.), usually about 65 to 85 ° C. The soft spot of such a reaction product can be adjusted by the soft spot of carbonaceous components (1) and (2) and heat treatment conditions (for example, heat treatment under pressure), but at least It is preferable to reduce the soft spot of the reaction product by using the carbonaceous components (1) and (2) having a low soft spot.

 [0062] The reaction product after the heat treatment is a component (liquid component) containing the generated mesocarbon microbeads (unfired or raw mesocarbon microbeads, mesocarbon microbeads before firing). In the present invention, a combination of the carbonaceous component (1) and the carbonaceous component (2) (particularly, a combination of the liquid carbonaceous component (1) containing the primary QI component and the liquid carbonaceous component (2)). As a result, a spherical MCMB with a smooth surface that cannot be separated as particles in the bulk mesophase can be obtained.

 [0063] Recovery or separation of the mesocarbon microbeads of the liquid component (reaction mixture or reaction product) after the heat treatment is performed by a method known in the art such as sedimentation, filtration, centrifugation, solvent fractionation, etc. . Heat treatment with a lower viscosity than that of the carbonaceous component (1) alone by mixing the carbonaceous component (1) with the carbonaceous component (2), which is less aromatic than the carbonaceous component (1) It is considered that the later liquid component is interposed between the generated mesocarbon microbeads to prevent or suppress coalescence and aggregation of the mesocarbon microbeads. For this reason, in the present invention, it is easy to recover or separate mesocarbon microbeads having liquid component strength after heat treatment.

[0064] The recovered or separated mesocarbon microbeads are mixed with a suitable solvent [eg, tar medium oil, tar light oil, organic solvent (eg, xylene, toluene, benzene, quinoline, Lahydrofuran, dimethyl sulfoxide, dimethylformamide, hexane, etc.)] and then dried (eg, vacuum dried).

 [0065] The remaining liquid component from which the mesocarbon microbeads are separated may be reused as necessary. For example, the remaining liquid component may be used in place of all or part of at least one of the carbonaceous component (1) and the carbonaceous component (2) in the production method of the present invention.

 [0066] The yield of mesocarbon microbeads obtained by the method of the present invention is high, for example, 12.5% by weight or more (eg, 12.5-50% by weight), preferably 12.8% based on the dewatered raw material. % By weight (eg 12.8-40% by weight), more preferably 13% by weight (eg 13-35% by weight), in particular 13.5% by weight (eg 13.5-30% by weight) %). In general, the more an aliphatic planar unit has a larger amount of aliphatic carbon, which is a reactive site, the higher the reactivity for generating MCMB, but such a raw material does not exist in the past. I got it. In the present invention, by combining the carbonaceous component (1) and the carbonaceous component (2), the aromatic planar unit is enlarged and the structure is in a trade-off relationship with a large amount of aliphatic carbon. MCMB can be obtained with good yield.

 [0067] It should be noted that the method of the present invention requires that the MCMB (raw MCMB) produced after the heat treatment is sufficient if it includes at least the step of heat treating the carbonaceous component (1) and the carbonaceous component (2). Furthermore, you may bake. By such firing treatment (graphitization treatment), fired MCMB (graphitized MCMB) can be obtained.

 [0068] The present invention also includes spherical (especially true spherical) mesocarbon microbeads (MCMB) with very few deposits (or surface irregularities) attached to the surface. Such MCMB is not particularly limited, but can be obtained, for example, by the above method (method using carbonaceous component (1) and carbonaceous component (2)).

[0069] For example, assuming that the MCMB of the present invention is a spherical shape, and the apparent specific surface area of MCMB calculated from the particle size is S1, and the BET specific surface area of MCMB is S2, the MCMB represented by S2ZS1 The degree of unevenness is, for example, 6 or less (for example, about 1 to 5.5), preferably 5 or less (for example, about 1.1 to 4.9), and more preferably 1.2 to 4.8 (for example, 1. about 3 to 4.5), usually 1 to 5, 4 or less [eg 1 to 3.7, preferably 1.2 to 3.6, more preferably Preferably, it can be set to 1.3 to 3.3, particularly 3 or less (for example, about 1.5 to 2.5). The above irregularity is an index indicating the degree of adhesion of the deposit on the MCMB surface. When the irregularity is 1, it indicates that the MCMB is spherical. The larger the irregularity, the higher the surface irregularity (or the primary QI component, etc.). This indicates that there are many deposits). The apparent specific surface area S 1 can be obtained by dividing the entire surface area of MCMB by the mass of MCMB. The surface area of MCMB is the surface area of a true sphere when the particle size of MC MB is 2r, that is, S l = 4 7u r ²

[0070] The shape of the mesocarbon microbeads of the present invention is spherical (especially true spherical), and as described above, the surface has no deposit (or less deposit), It is smooth without large concaves and convexes.

 [0071] Further, the mesocarbon microbeads of the present invention show a sharp particle size distribution and the particle size is uniform).

 [0072] The particle size distribution of the mesocarbon microbeads can be easily measured by a laser light diffraction method. In the cumulative frequency distribution, the particle size (D

 50) is an indicator of the average particle size, and the spread of the particle size distribution is 90% cumulative with respect to the 10% cumulative particle size (D).

 Ten

 The ratio (D ZD) can be expressed by a ratio of diameter (D), and the ratio (D ZD) is referred to as uniformity (D ZD).

 90 90 10 90 10 A large value of this uniformity indicates a broad particle size distribution, and a small value indicates a particle size distribution with a uniform particle size. D of mesocarbon microbead

 50, based on volume, column f is 5 to 200 μm, typically 6 to 150 μm, usually 8 to 120 / zm, preferably about 10 to 100 / ζ πι. May be. In particular, D is preferably 5-50 / ζ πι

 50

 Alternatively, it may be about 5 to 40 111, more preferably about 15 to 30 / ζ πι. In addition, the particle size distribution of the mesocarbon microbeads of the present invention is narrow. For example, the uniformity (D / D) is 2

 90 10

0 or less (for example, 2 to 15), preferably 8 or less (for example, 2.5 to 8), more preferably 7 or less (for example, 3 to 7), particularly preferably 6 or less (for example, 3.5 to 6) It may be about. The particle size can also be controlled by classification or the like.

[0073] As described above, the MCMB of the present invention is a spherical particle having a relatively small particle size, not a Balta shape. Therefore, the MCMB of the present invention has an appropriate aromatic carbon fraction. For example, the MCMB of the present invention is excellent in IR (infrared absorption spectrum). Wave number corresponding to the C-H stretching vibration of aromatic carbon (e.g., 3050 cm ^_1) the absorption intensity and II, the absorption strength of the wave number corresponding to the C-H stretching vibration of aliphatic carbon (e.g., 2920 cm ^_1) Assuming 12, the value of 11 / (II +12) is 0.5 to 0.8, preferably 0.55 to 0.75, more preferably ί or 0.57 to 0.7, usually 0. May be around 5 ~ 0.7! / ヽ.

[0074] In addition, MCMB usually contains a small particle size component (primary QI component) in addition to the secondary QI component. Such primary QI content plays an important role in MCMB generation and particle size control as described above, but primary QI content has low crystallinity when considering the use of negative electrode materials for lithium secondary batteries. In order to reduce the discharge capacity and the initial efficiency, it is preferable that the MCMB does not contain as much as possible. However, with the conventional method, the content of primary QI in MCMB could not be removed efficiently. On the other hand, in the present invention, as described above, the amount of primary QI contained in the MCMB is extremely reduced due to the effect of improving the dispersibility of the primary QI in the reaction product due to the aliphatic component. For example, the content ratio of particles having an average particle size of 1.85 m or less with respect to the entire MCMB (that is, small particles that are not MCMB) is, for example, 7% by volume or less (for example, about 0 to 6.5% by volume), preferably Is 6% by volume or less (for example, about 0.3 to 5.5% by volume), more preferably 5% by volume or less (for example, about 0.5 to 4.5% by volume), usually 0.8 to 5% by volume. % (For example, about 1 to 4.7% by volume).

 [0075] (fired mesocarbon microbeads)

The present invention also includes calcined mesocarbon microbeads (graphitized mesocarbon microbeads) having a smooth surface. Such calcined mesocarbon microbeads can be obtained, for example, by calcining the mesocarbon microbeads (raw mesocarbon microbeads). That is, since the MCMB is a spherical (particularly true spherical) particle with extremely small surface irregularities, the shape is reflected even after firing, and the shape of the fired MCMB is spherical with a smooth surface. . Such calcined MCM B is a spherical carbon material containing MCMB as a calcining component, and has a very high crystallinity. For example, the crystallinity of calcined MCMB is higher than when calcining only the carbonaceous component (1) without combining the carbonaceous component (2). In particular, the MCMB should have a smooth and spherical surface and be appropriately hydrogenated with little primary QI. Therefore, MCMB with good crystallinity is likely to be produced by firing because of the good molecular mobility with few defects and strains in the aromatic ring. For example, the crystal structure of the graphitized mesocarbon microbeads has a value of plane spacing (crystallite spacing) d (002), for example, 0.335 to 0.340, preferably 0.335 to 0. It may be about 338 nm (for example, 0.335 to 0.336 nm), and usually about 0.3354 to 0.3357 nm. Until now, no carbon material having such a spherical shape and high crystallinity has been known. Note that various prior art documents may include numerical values including the theoretical value (0.3354 nm) generally corresponding to graphite for the value of d (002). There is no specific description of calcined M CMB having a proximity d (002) and its production method. Spherical fired MCMB has a small specific surface area, so that it can improve initial efficiency, packing density, safety, etc. when used for electrodes. For example, in lithium secondary battery applications, it is possible to increase the edge portion as the lithium inlet / outlet and improve the initial efficiency and rate characteristics.

[0076] The calcined MCMB of the present invention is a carbon material obtained by calcining (graphitizing or graphitizing) the mesocarbon microbeads (raw MCMB) as described above. In the case of firing using the above method, after the heat treatment, the produced mesocarbon microbeads (raw mesocarbon microbeads) are separated from the heat treated product, and the separated mesocarbon microbeads are fired. Thus, calcined mesocarbon microbeads can be obtained.

[0077] Such a carbon material (calcined mesocarbon microbeads) may be obtained by calcining (or graphitizing) the mesocarbon microbead as it is, and after carbonizing (or carbonizing or carbonizing). It may be obtained by firing treatment. In the case of carbonization treatment, the carbonization temperature (or final temperature reached) may be, for example, about 450 to 1500 ° C, preferably about 500 to 1200 ° C, and more preferably about 500 to 1100 ° C. Carbonization can usually be performed in a non-oxidizing atmosphere (especially in an inert atmosphere such as nitrogen, helium or argon gas) or in a vacuum. Carbonization can be performed in a conventional fixed bed or fluidized bed type carbonization furnace (such as a lead hammer furnace, a tunnel furnace, or a single furnace). The furnace heating method and type are not particularly limited! [0078] The firing temperature (or final temperature reached) is, for example, 1700 to 3200 ° C, preferably 180 0 to 3100. C, more preferred <1900-3000. About C (for example, 1950-2900. C), 2000-2800. It may be about C, usually 2500-3200. It may be about C.

 [0079] The firing treatment (graphitization treatment) may be performed in the presence of a reducing agent (for example, coatas, graphite, charcoal, etc.) as necessary. The firing treatment can be usually performed in a non-oxidizing atmosphere (particularly, an inert atmosphere such as helium, argon, neon gas) or in a vacuum, and can usually be performed in an inert atmosphere. . The firing treatment can be normally performed in a graphitization furnace, and the graphitization furnace is not particularly limited as long as it is a furnace that can reach a predetermined temperature. For example, an Acheson furnace Examples thereof include a direct current graphitization furnace and a vacuum furnace. The firing treatment may be performed in the presence of a boron compound. For such technology, reference can be made to JP-A-11-283625. When fired in the presence of a boron compound, a fired MCMB with a high degree of graphite can be obtained. However, when the graphitization furnace (such as the Atchison furnace) is damaged or applied to the negative electrode material of a lithium battery, an overvoltage is generated. In order to increase the size, in the present invention, it is preferable to fire in the absence of a boron compound.

 [0080] The final calcined product of mesocarbon microbeads is pulverized by a pulverizer (ball mill, hammer mill, etc.) to be used as a carbon material as a final product.

 [0081] The carbon material (fired mesocarbon microbeads) of the present invention has high crystallinity and is a special carbon material such as various materials, for example, electrode materials (for example, lithium secondary battery negative electrode materials and electric discharge machining electrodes). It can be used effectively as a single material or filler (plastic conductive filler, etc.).

[0082] In particular, the carbon material of the present invention can be suitably used as a constituent material of a negative electrode for a lithium secondary battery (further, a lithium secondary battery). When the fired MCMB of the present invention is used as a negative or negative electrode material for a lithium secondary battery, the capacity can be improved as the crystallinity is improved, and the initial force, cycle characteristics, safety, rate characteristics, environmental load reduction, etc. The characteristics of can be improved. In other words, by improving crystallinity, (i) improving conductivity, improving cycle characteristics, and (ii) reducing the amount of functional groups on the MCMB surface by hydrogenation, smoothness of the particle surface, primary QI, The small surface area improves efficiency and safety. In addition, the use of carbonaceous component (2) can reduce metal components and benzpyrene components in MCMB, reducing the environmental impact. Can be reduced. Therefore, the present invention also includes a negative electrode (or negative electrode material) for a lithium secondary battery formed from the fired mesocarbon microbeads. For example, a method of forming a mixture containing a carbon material, a binder, etc .; a method of applying a paste containing a carbon material, an organic solvent, a binder, etc. to the carbon material using an application means (such as a doctor blade). It can be set as the negative electrode (or negative electrode material) for lithium secondary batteries of a shape. In forming the negative electrode, it may be combined with the terminal as necessary.

 [0083] The negative electrode current collector is not particularly limited, and a known current collector, for example, a conductor such as copper can be used. As the organic solvent, a solvent that can dissolve or disperse the solder is usually used, and examples thereof include organic solvents such as N-methylpyrrolidone and N, N-dimethylformamide. The organic solvents may be used alone or in combination of two or more. The amount of the organic solvent used is not particularly limited as long as it becomes a paste, and is, for example, generally 60 to 150 parts by weight, preferably 60 to about LOO parts by weight with respect to 100 parts by weight of the negative electrode carbon material.

[0084] Examples of the noinder include fluorine-containing resin (polyvinylidene fluoride, polytetrafluoroethylene, etc.) and the like. The amount of Noinda used (in the case of a dispersion, the amount used in terms of solid content) is not particularly limited. For example, 3 to 20 parts by weight, preferably 100 parts by weight of the carbon material (baked product) May be about 5 to 15 parts by weight (for example, 5 to 10 parts by weight). The method for preparing the paste is not particularly limited, and examples thereof include a method of mixing a mixed liquid (or dispersion liquid) of a binder and an organic solvent and a carbon material.

[0085] Note that the negative electrode may be manufactured by using the carbon material obtained by the method of the present invention and a conductive material (carbonaceous material or conductive carbon material) in combination. The use ratio of the conductive material is not particularly limited, but is usually about 1 to 10% by weight, preferably about 1 to 5% by weight, based on the total amount of the carbon material and the carbonaceous material obtained by the method of the present invention. . By using a conductive material [for example, a carbonaceous material such as carbon black (for example, acetylene black, thermal black, furnace black)], conductivity as an electrode may be improved. Conductive materials can be used alone or in combination of two or more. Note that the conductive material can be effectively used together with the carbon material by, for example, a method of mixing a paste containing a carbon material and a solvent and applying the paste to the negative electrode current collector. [0086] The coating amount of the negative electrode current collector of the paste is not particularly limited, usually, 5～15MgZcm 2 mm, preferably 7～13MgZcm ² approximately. The thickness of the film applied to the negative electrode current collector (the thickness of the paste) is, for example, about 50 to 300 m, preferably about 80 to 200 m, and more preferably about 100 to 150 m. Note that after the application, the negative electrode current collector may be subjected to a drying treatment (for example, vacuum drying or the like).

 [0087] The carbon material (fired MCMB) of the present invention can constitute a lithium secondary battery as a negative electrode constituent material as described above. In particular, the carbon material of the present invention can constitute a lithium secondary battery for enabling repeated charge and discharge. A lithium secondary battery is a combination of the negative electrode (negative electrode containing the carbon material), a positive electrode capable of occluding and releasing lithium, and an electrolyte, and a separator (such as a commonly used porous polypropylene nonwoven fabric). Polyolefin-based porous membrane separators, etc.), current collectors, gaskets, sealing plates, cases, and other battery components can be used to assemble and manufacture by conventional methods. For the details of the method of assembling the lithium secondary battery, for example, the method described in JP-A-7-249411 can be referred to.

 [0088] The positive electrode is not particularly limited, and a known positive electrode can be used. The positive electrode can be composed of, for example, a positive electrode current collector, a positive electrode active material, a conductive agent, and the like. Examples of the positive electrode current collector include aluminum. Examples of positive electrode active materials include TiS, MoS, NbSe, and FeS.

 2 3 3

, VS, VSe and other layered metal chalcogenides; CoO, Cr 2 O, TiO,

2 2 2 3 5 2

CuO, V O, Mo 0, V O (· Ρ O), Mn 0 (-Li 0), LiCoO, LiNiO, LiMn

 Metal oxides such as 3 6 3 2 5 2 5 2 2 2 2 2 o; polyacetylene, polyarine, polyparaphenylene, polythiol ヱ

Four

 Conductive conjugated polymer substances such as polypyrrole and polypyrrole can be used. Preferably, metal oxides (especially V 2 O, Mn 0, LiCoO 3) are used.

 2 5 2 2

 [0089] Examples of the electrolyte include propylene carbonate, ethylene carbonate, and γ

Aprotic solvents such as butyrolatatane, tetrahydrofuran, 2-methyltetrahydrofuran, dioxolane, 4-methyldioxolane, sulfolane, 1,2-dimethoxyethane, dimethyl sulfoxide, aceto-tolyl, Ν, ジ メ チ ル dimethylformamide, diethylene glycol, dimethyl ether, etc. It can be illustrated. In addition, the electrolyte is a solution of LiPF, LiClO, LiBF, LiAsF, LiSbF, LiAlO, LiAlCl, LiCl, Lil, etc. in these aprotic solvents. Also included are those in which a salt that produces a cation that is difficult to solvate is dissolved. The electrolytes may be used alone or in combination of two or more. Preferred electrolytes include strong solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, dioxolane, 4-methyldioxolane as solvents that are stable even in a strong reducing atmosphere, and ether solvents that are stable in a reducing atmosphere, and the non-protonic solvents described above. (Preferably a mixed solvent of two or more) includes a solution in which the above exemplified salt is dissolved.

 [0090] Note that the lithium secondary battery can have any shape or form such as a cylindrical shape, a rectangular shape, or a button shape.

 Industrial applicability

[0091] According to the method of the present invention, spherical mesocarbon microbeads having a narrow particle size distribution and a smooth surface can be obtained with high yield. In addition, the mesocarbon microbeads (fired MCMB) or carbon material of the present invention is a lithium secondary battery negative electrode material having high crystallinity, an electric discharge machining electrode, a capacitor electrode material, a high-density high-strength carbon material, or the like. It can be used suitably for applications such as a unitary material of special carbon materials or plastic conductive fillers.

 Example

 [0092] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0093] [Measurement of aromatic carbon fraction f]

 a

 A sample was prepared by adding about 0.5 mol% of acetyl acetone acetone salt as a relaxation agent to the carbonaceous component (1) or the carbonaceous component (2). The measurement was performed by a gated proton decoupling method at a temperature of 150 ° C. using a 400 MHz FT-NMR apparatus (ECX-400) manufactured by JEOL Ltd. From the ratio of the area intensity of aromatic carbon and the area intensity of non-aromatic carbon in the obtained spectrum, the aromatic carbon fraction f

 a was calculated.

 [0094] [Softening point]

 The soft saddle point SP was measured using a heat measuring device (FP83, manufactured by METTLER TOLEDO CO., LTD.).

[0095] [Solvent analysis]

According to JIS K-2425, toluene insoluble matter (TI) and primary quinoline insoluble matter (QI) were measured. The QI produced by the reaction (A QI) is quinoline insoluble in the reaction product after heat treatment. Q and the yield of the reaction product YX 100 (%) and the primary quino

Β

 The value was calculated from the phosphorus insoluble content Q as the value (Q XY) -Q. Also, the ratio of A QI to Q (A QI

 A B A A

 / Q) was calculated in the same manner.

 A

 [0096] In addition, the heptane soluble fraction (HS) was measured by mixing lOOmg sample with 30ml dimethylformamide and 30ml heptane. Then, 30 ml of the upper layer divided into two layers was collected, the solvent was removed with an evaporator, the weight was measured, and the weight% in the sample was calculated.

 [0097] [Electron microscope observation]

 The electron microscope was an S-3000 Scanning Electron Microscope manufactured by Hitachi, Ltd., and the applied voltage was 20 kV. And in Examples 3 to 9 and Comparative Examples 2 to 15, from the obtained electron micrographs, the particle shape was evaluated according to the following criteria:

[0098] A: The particle surface is smooth with deposits on the particle surface.

 B: There are deposits on the particle surface, and irregularities are seen on the particle surface

 C: Particles are not spherical but crushed

 D: Particles are agglomerated.

[0099] [Observation with polarization microscope]

 Mesocarbon microbeads and acrylic resin (transparent resin manufactured by Refinetech Co., Ltd.) were mixed at a weight ratio (1Z2), molded and polished to obtain a sample for observation. The structure of the sample for observation was observed through a gypsum plate under an orthogonal-col by Olympus BX60M using a halogen incandescent lamp as the light source.

[0100] [X-ray diffraction measurement]

 X-ray diffraction measurement was performed using RINT2000 manufactured by Rigaku Corporation at a tube voltage of 40 kV and a tube current of 200 mA.

[0101] [Particle size distribution measurement]

 For the particle size (particle size), D / D and D were measured using a particle analyzer (JEOL HELOS SYSTEM), and the amount of particle size of 1.85 / z m or less was calculated, and D / Ό was calculated. Ma

10 50 90 90 10

From the particle size measured with a particle analyzer, Specific surface area (apparent specific surface area) SI was also measured.

[0102] [Measurement of BET specific surface area and roughness]

 The BET specific surface area S2 of the particles was measured using a nitrogen adsorption BET specific surface area measuring device (manufactured by Quantachrome, NOVA2000). Then, the unevenness degree (S2ZS1) was determined by dividing the BET specific surface area S2 by the apparent specific surface area S1 determined by the particle size distribution measurement. When the irregularity is 1, it means that the particle is a true spherical particle, and as the irregularity increases, the irregularity on the particle surface increases (that is, the smoothness of the particle surface decreases).

[0103] [Confirmation of sludge generation]

 The mixture of the filtered carbonaceous component (1) and carbonaceous component (2) at 100 ° C was checked for contamination on the filter paper according to the quinoline insoluble content analysis method CFIS K-2425).

 [0104] [Measurement of IR intensity ratio]

 The produced mesocarbon microbeads (mesocarbon microbeads before firing) and KBr were mixed at a ratio of the former Z latter (weight ratio) = 1Z100, and a molded sample was produced with a molding machine. Then, using a spectroscope (Thermo Nicole, AVATAR370FT-IR), the IR ^ vector (infrared absorption spectrum) of the molded sample was measured at room temperature by the transmission method. From this IR spectrum and the IR ^ vector measured with KBr alone, IR spectra of mesocarbon microbeads were obtained. Then, the relative aromatic fraction was calculated from the aromatic C-H stretching peak (3050 cm—intensity 11 and the aliphatic C-H stretching peak (2920 cm_strength 12) from the obtained spectrum. Since mesocarbon microbeads are insoluble in solvents and do not soften, the relative aromatic fraction by IR was applied instead of the aromatic fraction by NMR measurement. The larger the value of IlZ (Π +12), the higher the relative aromatic fraction, as in the NMR measurement.

 [0105] [Electrode property evaluation method]

 LiCoO was used for the positive electrode body. N, N-dimethylformamide is used as the negative electrode body.

 2

 As a solvent, mixed mesocarbon microbeads with graphite and polyvinylidene fluoride are mixed.

After forming into a slurry, the slurry obtained on the copper plate roll was applied at a thickness of 100 to 140 / zm using a negative electrode molding machine, and vacuum dried at 200 ° C. to obtain a negative electrode body. As electrolyte, Lithium perchlorate was dissolved at a ratio of ImolZL in a mixed solvent of ethylene carbonate and jetyl carbonate (weight ratio 1: 1) to obtain an electrolytic solution. A lithium secondary battery was produced using a polypropylene nonwoven fabric as a separator. The discharge characteristics of the obtained lithium secondary battery were measured.

[0106] Charging was carried out with constant current charging with ImAZcm ² followed by constant potential charging with ImV for a total charging time of 12 hours. Further, discharge was constant current ImAZcm ^2. The electrode characteristics were measured until the discharge capacity dropped to 1.3V.

 [0107] The mesocarbon microbead graphite obtained (fired) in the examples was obtained by holding the mesocarbon microbead in a nitrogen atmosphere under conditions of pressure 0. IMPa and temperature 1000 ° C. Carbonized for a period of time, and then in argon atmosphere, pressure 0. IMPa and temperature 2800 ° C (Example 1, Example 2 and Comparative Example 1) or 3000 ° C (Examples 3 to 9, Comparative Examples 2 to This was performed by firing under the condition of 12).

 [Example 1]

Coal tar (f = 0. 941, QI2 . 58 weight _^0/0) and aromatic low ethylene bottom oil (al

 f = 0.730, QIO. 0% by weight) and the weight ratio of the former Z and the latter = 80Z20.

 The ratio of the aromatic carbon fraction of the ethylene bottom oil to the aromatic carbon fraction of the tar tar = 0.776), and the reaction was carried out by heat treatment at 430 ° C for 8 hours under pressure with nitrogen in an autoclave (0.5 MPa). The product was obtained in a yield of 63.6% by weight. The reaction product was washed with tar medium oil and tar light oil, respectively, to obtain mesocarbon microbeads at a yield of 14.5% by weight based on the dehydrated raw material.

[0109] The particle size distribution of the obtained mesocarbon microbeads is sharp (D = 7.1 m, D

 10 50

= 27. 6 ^ πι, D = 37., uniformity (D / Ό) = 5. 25)

 90 90 10

 Observation showed that the surface was smooth. According to the X-ray diffraction measurement of mesocarbon microbeads graphitized at 2800 ° C, d (002) was 0.3356 nm and the crystal structure was developed. In the electrode characteristics evaluation, the discharge capacity was 337.3 mAhZg, and the initial efficiency was as high as 92.4%.

[0110] (Example 2)

In Example 1, coal tar (f = 0. 941, QI2 . 58 weight _^0/0) and aromatic low There ethylene bottom oil (f = 0. 730, QI0 . 0 wt _^0/0) weight ratio of the former Z latter = 50 a2

 Mesocarbon microbeads were prepared in the same manner as in Example 1, except that the ratio was 50 (the ratio of the aromatic carbon fraction of ethylene bottom oil to the aromatic carbon fraction of coal tar = 0.776). The yield of the reaction product of coal tar and ethylene bottom oil was 51.4%, and the yield of mesocarbon microbeads was 15.6% by weight based on the dehydrated raw material.

[0111] The particle size distribution of the obtained mesocarbon microbeads is sharp (D = 13.7 m, D

 10 50

= 41. Θ ^ πι, ϋ = 55., uniformity (D / Ό) = 4.06)

 90 90 10

 Observation showed that the surface was smooth. According to the X-ray diffraction measurement of mesocarbon microbeads graphitized at 2800 ° C, d (002) was 0.3354nm and the crystal structure was developed. In the electrode characteristic evaluation, the discharge capacity was 347.3 mAhZg, and the initial efficiency was as high as 92.0%.

 [0112] (Comparative Example 1)

 In Example 1, the conditions were the same as in Example 1 except that only coal tar was used. The yield of the reaction product of coal tar was 69.9%, and the yield of mesocarbon microbeads was 12.2% by weight based on the dehydrated raw material.

 [0113] The particle size distribution of the obtained mesocarbon microbeads is broad (D = 1.1 m, D =

 10 50

16. = 23., homogeneity (D / Ό) = 21.6), observed by electron microscope

 90 90 10

 In the figure, an uneven shape with a deposit on the surface is shown. According to X-ray diffraction measurement of mesocarbon microbeads graphitized at 2800 ° C, d (002) was 0.3358 nm. In the electrode characteristic evaluation, the discharge capacity was 327.3 mAhZg, and the initial efficiency was 92.4%.

[0114] (Example 3)

Liquid coal tar (f = 0. 941, QI2 . 58 weight _^0/0, HS1. 5 wt _^0/0) and aromatic al

 Low liquid ethylene bottom oil (f 0 · 730, QI 0.0% by weight, HS 10% by weight), a2

The former Z, the latter = 80Z20, with a weight ratio of 70 ° C, stirring for 1 hour, and heat treatment in an autoclave under pressure with nitrogen (0.5 MPa) at a rotation speed of 600 rpm and 430 ° C for 8 hours. The reaction product was obtained in a yield of 63.6% by weight. The reaction product and tar medium oil were stirred and mixed at 130 ° C for 30 minutes at a weight ratio of the former Z latter = 1Z1.5, and then centrifuged (5000 rpm for 30 minutes) to obtain a precipitate. Repeat the same operation once more, then precipitate And toluene were mixed in the weight ratio of the former Z latter = 1Z2 at 80 ° C. for 30 minutes, and then washed by pressure filtration at 80 ° C. to obtain a precipitate. The same operation was repeated once more, and then the precipitate was vacuum dried (at 120 ° C for 60 minutes) to obtain mesocarbon microbeads based on the dehydrated raw material (dehydrated tar). Obtained in wt%.

[0115] The particle size distribution of the obtained mesocarbon microbeads is sharp (D = 7.1 m, D

 10 50

= 27. 6 ^ πι, D = 37., uniformity (D / Ό) = 5. 25)

 90 90 10

 Observation showed that the surface was smooth. According to the X-ray diffraction measurement of mesocarbon microbeads graphitized at 3000 ° C, d (002) was 0.3356 nm and the crystal structure was developed. In the electrode characteristic evaluation, the discharge capacity was 35.4 mAhZg, and the initial efficiency was as high as 93.8%.

[0116] (Example 4)

 In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3, except that the weight ratio of coal tar and low-aromatic ethylene bottom oil was changed to the former Z latter = 50 Z50. The yield of the reaction product of coal tar and ethylene bottom oil was 51.4%, and the yield of mesocarbon microbeads was 15.6% by weight based on the dehydrated raw material (dehydrated tar).

 [0117] The particle size distribution of the obtained mesocarbon microbeads is sharp (D = 13.7 m, D

 10 50

= 41. Θ ^ πι, ϋ = 55., uniformity (D / Ό) = 4.06)

 90 90 10

 Observation showed that the surface was smooth. According to the X-ray diffraction measurement of mesocarbon microbeads graphitized at 3000 ° C, d (002) was 0.3354 nm, and the crystal structure was developed. In the electrode characteristics evaluation, the discharge capacity was 358.8 mAhZg, and the initial efficiency was as high as 93.4%.

[0118] (Comparative Example 2)

 In Example 3, mesocarbon microbeads were prepared in the same manner as Example 3 except that only coal tar was used. The yield of the reaction product of coal tar was 69.9%, and the yield of mesocarbon microbeads was 12.2% by weight based on the dehydrated raw material (dehydrated tar).

[0119] The particle size distribution of the obtained mesocarbon microbeads is broad (D = 1.1 m, D = 16. = 23., homogeneity (D / Ό) = 21.6), observed by electron microscope

90 90 10

 In the figure, an uneven shape with a deposit on the surface is shown. According to the X-ray diffraction measurement of mesocarbon microbeads graphitized at 3000 ° C, d (002) was 0.3358 nm. In the electrode characteristic evaluation, the discharge capacity was 338. ImAhZg, and the initial efficiency was 92.4%.

[0120] (Comparative Example 3)

The coal tar used in Example 3 was subjected to pressure filtration (160 ° C and 0.3 MPa) to remove liquid solid coal (primary QI) (f = 0.941, QI0.0 weight ⁰ / ₀ , HS1.5 al

 % By weight). In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3 except that only the coal tar from which the obtained solid content was removed was used. Since the product was not spherical but crushed because of the absence of QI, the mesocarbon microbeads graphitized at 3000 ° C had a low crystallinity and low charge and discharge capacity. It was.

 [0121] (Comparative Example 4)

 In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3 except that only coal tar was used and heat treatment was performed at 450 ° C. for 4 hours. As a result of increasing the heat treatment temperature, the particle size became too large, and the mesocarbon microbeads could not keep a spherical shape and were in a pulverized state. Since the mesocarbon microbeads obtained in the examples (for example, Example 4) were spherical even if the particle diameter (D50) was larger, the aliphatic in ethylene bottom oil was used in addition to the primary QI. It is thought that the component contributes to spheroidization.

 [0122] (Comparative Example 5)

 In Example 3, the solids removed from coal tar in Comparative Example 3 were washed with quinoline and then washed with acetone (f = 0.99, QI 100% by weight, HS 0.0% by weight, solids al

 Obtained). A mesocarbon microphone mouth bead was prepared in the same manner as in Example 3 except that only this solid content was used. The graphite product graphitized at 3000 ° C is a graphitized product of the primary QI content itself, which has a small particle size, low crystallinity, low discharge capacity, and low charge / discharge yield.

[0123] (Comparative Example 6)

In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3 except that only ethylene bottom oil was used and heat treatment was performed at 400 ° C. There is no primary QI As a result, the product was not spherical but crushed. In addition, because the aromatic carbon content in the raw material was low, the crystallinity of the mesocarbon microbeads graphitized at 3000 ° C was low, and the discharge capacity and initial efficiency were also low. When the heat treatment temperature was 410 ° C or higher, the reaction system was coking and could not be stirred.

[0124] (Comparative Example 7)

 The coal tar used in Example 3 was vacuum-distilled and a soft anchor point of 96.6 ° C pitch (f = 0.

 al

940, QI 4.1% by weight, HSO. 1% by weight). In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3 except that only the pitch of this high softening point was used. Since the softening point of the reaction product (reaction oil) was 171.0 ° C, the primary QI and pitch components remained around the beads even after separation and washing, which was difficult to separate and wash the mesocarbon mic bead. There were many scattered.

 [0125] (Comparative Example 8)

 In Example 3, mesocarbon microbeads were prepared in the same manner as in Example 3 except that only coal tar was used and heat treatment was performed at a pressure of 1. IMPa. Even when the reaction pressure was increased, the particle size distribution, surface condition, etc. were almost the same as in Comparative Example 2.

 [0126] (Example 5)

Implementation f Column 3 [freezing! Teヽ, liquid Kono letter Norre (f = 0. 951, QI3 . 80 weight _^0/0, HS1. 4

 al

 % By weight) and low-aromatic liquid ethylene bottom oil (f 0 · 755)

 a2, QIO. 0% by weight,

(Mesocarbon microbeads were prepared in the same manner as in Example 3 except that HS 6.5% by weight) was mixed.

[0127] (Example 6)

 In Example 5, mesocarbon microbeads were prepared in the same manner as in Example 4 except that the weight ratio of coal tar and ethylene bottom oil was changed to the former Z latter = 50 Z50.

 [Example 7]

 In Example 5, instead of ethylene bottom oil, liquid ethylene bottom oil (f = 0. 6

 a2

53, QIO. 0 wt%, HS 21.7 wt%) were used in the same manner as in Example 5 to prepare relatively good mesocarbon microbeads. In addition, to the mixture before heat treatment No sludge was produced. In addition, sludge formation could not be confirmed even in a mixture of coal tar and ethylene bottom oil mixed with the former z latter = 50 Z50 by weight. Furthermore, in the mixture mixed at the weight ratio of the former and the latter = 30-70, the force that confirmed the formation of sludge. The addition of 5% by weight of quinoline to this mixture showed that the formation of sludge could not be confirmed.

[0129] (Comparative Example 9)

 Mesocarbon microbeads were prepared in the same manner as in Example 5 except that only coal tar was used in Example 5.

[0130] (Example 8)

 In Example 5, instead of coal tar, liquid coal tar (f = 0.964, QI

 al

 A relatively good mesocarbon microbead was prepared in the same manner as in Example 5 except that 1.00 wt% and HS 1.3 wt% were used.

[0131] (Comparative Example 10)

 Mesocarbon microbeads were prepared in the same manner as in Example 8 except that only coal tar was used in Example 8.

[0132] (Example 9)

 In Example 5, instead of coal tar, liquid coal tar (f = 0.959, QI

 al

 5. Comparatively good mesocarbon microbeads were prepared in the same manner as in Example 5 except that 30 wt% and HS 1.3 wt% were used.

[Comparative Example 11]

 Mesocarbon microbeads were prepared in the same manner as in Example 9, except that only coal tar was used in Example 9.

[0134] (Comparative Example 12)

In Example 3, instead of the coal tar and ethylene bottom oil, decrease in liquid pressure steam Tomezan渣(asphalt, f = 0. 286, QIO . 0 wt _^0/0, HS76. 1 weight _^0/0) using only

 a2

The mesocarbon microbeads were prepared in the same manner as in Example 3 except that the heat treatment was performed at 400 ° C. The product was not a sphere but a crushed material due to the absence of QI. In addition, because the aromatic carbon fraction in the raw material is low, the mesocarbon microbeads graphitized at 3000 ° C. The crystallinity of the laser was low, the discharge capacity was low, and the initial efficiency was low. When the heat treatment temperature was 410 ° C or higher, the reaction system was caulked and could not be stirred.

 [0135] The results are shown in Tables 1 and 2.

[0136] [Table 1]

^

table 1

Table 2

[0138] Fig. 1 shows an electron micrograph (285 times) of the unfired MCMB obtained in Example 3. Fig. 2 shows an electron micrograph of the unfired MCMB obtained in Example 4 (160 times). FIG. 3 shows an electron micrograph (660 × magnification) of the unfired MCMB obtained in Comparative Example 2, respectively.

 [0139] As is clear from the table, compared to the comparative example, in the example, the mesocarbon microbeads having a spherical shape with a narrow particle size distribution and a smooth surface were obtained with high yield.

Claims

The scope of the claims

 [1] The mesocarbon microbeads (1) capable of forming mesocarbon microbeads and a mesocarbon mixture (1) having a lower aromaticity than the carbonaceous component (1) and at least a step of heat-treating the mesocarbon microbeads. A method for producing carbon microbeads, wherein a ratio f / ί of an aromatic carbon fraction f of the carbonaceous component (2) to an aromatic carbon fraction f of the carbonaceous component (1) is 0.95 or less. al a2 a2 al

 Production method.

 [2] The method according to claim 1, wherein f / repulsive force is 0.9 or less.

 a2 al

 [3] The method according to claim 1, wherein the carbonaceous component (1) is composed of at least one selected from coal tar and coal tar pitch force.

[4] The carbonaceous component (1) has f = 0.9 to 0.99, and the primary quinoline insoluble content is 1

 al

 The process according to claim 1, wherein the carbonaceous component is -7% by weight.

[5] The carbonaceous component (2) may be hydrogenated! /, Or pitch and hydrogenated! 2. The method according to claim 1, comprising at least one selected from heavy oils.

[6] The method according to claim 1, wherein the carbonaceous component (2) is composed of 1S ethylene bottom oil, decant oil, wasphaltene, and pitch force using these as raw materials.

 [7] The carbonaceous component (2) contains f = 0.55-0.85, and heptane and dimethylformamide.

 a2

 The production method according to claim 1, wherein the content ratio of the component dissolved in heptane with respect to the mixed solvent containing the former Z latter (weight ratio) = iZi is 1 to 40% by weight.

[8] The production method according to claim 1, wherein the carbonaceous component (1) and the carbonaceous component (2) each have a soft spot of 60 ° C. or less.

[9] The ratio of carbonaceous component (1) to carbonaceous component (2) is the former Z latter (weight ratio) = 99Zl ~ 3

The method of claim 1, which is 0Z70.

[10] (i) The carbonaceous component (1) is liquid at room temperature, f = 0.93-0.97 and primary quinori

 al

 (Ii) the carbonaceous component (2) is liquid at room temperature, f = 0.6-0.8, and heptane And dimethylformamide before

 a2

Z The latter (weight ratio) = carbonaceous component with a component content of 2-30% by weight dissolved in heptane with respect to the mixed solvent containing iZi. (Iii) f / ί is 0.9. And The method according to claim 1, wherein the ratio of force (iv) carbonaceous component (1) to carbonaceous component (2) is the former Z latter (weight ratio) = 90 Z10 to 45Z55.

[11] The method of claim 1, wherein the mixture further comprises a compatibilizing agent.

 [12] The production method according to claim 1, wherein after the heat treatment, the generated mesocarbon microbeads are separated by heat treatment product force, and the separated mesocarbon microbeads are fired to obtain fired mesocarbon microbeads.

 [13] A mesocarbon microbead obtained by the method according to claim 1 and not fired, and in the infrared absorption spectrum, the absorption intensity of the wave number corresponding to the CH stretching vibration of aromatic carbon is II, Mesocarbon microbeads with an IlZ (II +12) value of 0.5 to 0.8, where the absorption intensity of the wave number corresponding to the C—H stretching vibration of aliphatic carbon is 12.

 [14] The degree of unevenness represented by S2ZS1 is 1 to 5 when the apparent specific surface area calculated as particle size force is S1 and the BET specific surface area is S2 as a spherical shape. The mesocarbon microbead described.

 [15] A spherical fired mesocarbon microbead obtained by firing the mesocarbon microbead according to claim 13.

 [16] The calcined mesoca-bon microbeads according to claim 15, which has a value of an interplanar spacing d (002) of 0.3354 to 0.3357 nm.

 [17] A negative electrode for a lithium secondary battery, formed of the fired mesocarbon microbeads according to claim 15.