JP5518316B2 - Carbon black composite and method for producing the same - Google Patents

Description

  The present invention relates to a carbon black composite and a method for producing the same.

  Conventionally, carbon black is contained in rubber, resin or the like to impart conductivity. In particular, since acetylene black has a chain structure of carbon particles, it has superior conductivity imparting ability compared to general carbon black.

  However, in recent years, there has been a demand for a conductive agent capable of imparting high conductivity without deteriorating the original properties of resins and the like, and in order to satisfy this requirement, carbon black having a further excellent conductivity imparting effect is required. Need to develop.

  In order to solve such problems, it has been proposed to use carbon nanotubes as a conductive agent, but the dispersibility is poor, and many post treatments are required for catalyst removal and crystallinity improvement, which is very expensive. It is.

To solve these problems, it has been proposed to generate carbon nanotubes in the reaction field of acetylene black (Patent Document 1), but the production conditions of carbon nanotubes and acetylene black are different, and simultaneous production in one production field is possible. By doing so, the quality may not be stable.
WO / 2007/013678

  An object of the present invention is to provide a carbon black composite excellent in conductivity imparting ability and a method for producing the same. The carbon black composite of the present invention can impart high conductivity to a resin or the like with a low filling amount.

The present invention employs the following means in order to solve the above problems.
(1) Supplying acetylene gas at a flow rate of 10 m ³ / h and thermally decomposing at 2000 ° C. to produce acetylene black, benzene as a carbon source, ferrocene as a catalyst, and thiophene as a co-catalyst at a mass ratio of 90: 8: 2 is a fiber that is gasified at 300 ° C., introduced at 50 to 100 m / s, and added with fibrous carbon produced by heat treatment at a temperature of 600 to 1000 ° C., and the fibrous carbon and acetylene black are combined. The carbon content is 30-50 % by mass, the fibrous carbon Raman intensity ratio (D / G value) is 0.24 or less, and the ash content defined by JIS K 1469 is 0.01% by mass or less. Characteristic carbon black composite.
(2) In the step of supplying acetylene gas at a flow rate of 10 m ³ / h and thermally decomposing at 2000 ° C. to produce acetylene black, benzene as a carbon source, ferrocene as a catalyst, and thiophene as a co-catalyst at a mass ratio of 90: 8: 2 gasified at 300 ° C., introduced at 50 to 100 m / s, added with fibrous carbon produced by heat treatment at 600 to 1000 ° C., and combined with fibrous carbon and acetylene black The fibrous carbon content is 30 to 50% by mass, the fibrous carbon Raman intensity ratio (D / G value) is 0.24 or less, and the ash content defined by JIS K 1469 is 0.01% by mass or less. A method for producing a carbon black composite.
(3) The method for producing a carbon black composite as described in (2) above, wherein the fibrous carbon has a diameter of 90 nm or less.

  The carbon black composite of the present invention is more excellent in conductivity imparting ability than conventional carbon black.

  The carbon black composite of the present invention is one in which fibrous carbon and carbon black are linked. The carbon black composite of the present invention preferably has an ash content defined by JIS K 1469 of 1.0% by mass or less. The ash is mainly composed of a catalyst for producing fibrous carbon, metal impurities (Fe, Ni, Co, etc.) and oxides thereof. If the ash content exceeds 1.0% by mass, for example, in the case of a Li ion secondary battery, metal deposition on the negative electrode is likely to occur during charging, and the risk of ignition due to a decrease in charge / discharge capacity or a short circuit through the separator. May cause sex.

  Coupling is not just contact, it means that it is physically fused with carbonaceous matter, and it is not easily separated by normal mechanical operations, but between the connected fibrous carbon and carbon black. Electrons can move freely without resistance. Therefore, even when mixed with a resin or the like, the carbon black composite remains as it is, and good dispersibility can be obtained and high conductivity can be maintained. When the fibrous carbon alone is mixed with other materials such as a resin, it is difficult to obtain good dispersibility due to orientation and entanglement between fibers, resulting in variations in conductivity. When carbon black and fibrous carbon are simply mixed, the shape is different and the variation further increases. However, one feature of the carbon black composite of the present invention is that it has excellent conductivity stability. Here, the fibrous carbon is preferably 10 to 50% by mass. When the fibrous carbon is less than 10% by mass, sufficient conductivity cannot be obtained, and when it exceeds 50% by mass, the connection with the carbon black is not sufficient, and at the same time, the dispersibility is due to aggregation of the fibrous carbon. It drops significantly.

  The fibrous carbon used in the carbon black composite of the present invention is carbon fiber (carbon fiber), vapor grown carbon fiber (VGCF), carbon nanotube, carbon nanofiber, or the like. In the present invention, fibrous carbon can be appropriately selected, but the fibrous carbon preferably has a diameter of 200 nm or less.

  As the fibrous carbon used in the carbon black composite of the present invention, all ordinary commercial products can be used. In addition, even when the Raman intensity ratio (D / G value) is high and the crystallinity is low, the Raman intensity ratio (D / G value) is 0.30 or less by introducing it into the hydrocarbon during the pyrolysis and combining it. Can be used.

  The carbon black composite of the present invention is produced by a method in which fibrous carbon is introduced during the thermal decomposition of hydrocarbons. By using this production method, the ash content defined in JIS K 1469 of the carbon black composite can be reduced to 1.0% by mass or less.

  Fibrous carbon used in the carbon black composite of the present invention can be produced by supplying heat to a high temperature field that is equal to or higher than the thermal decomposition temperature of the hydrocarbon and heat treating it. The thermal decomposition temperature of the hydrocarbon is particularly preferably 600 to 1000 ° C. As hydrocarbons, for example, saturated hydrocarbons such as methane, ethane, propane, butane, etc., unsaturated hydrocarbons having double bonds such as ethylene, propylene, butene, butadiene, etc., and triple bonds such as acetylene, propyne, butyne, etc. Unsaturated hydrocarbons, aromatic hydrocarbons such as benzene, toluene and xylene can be used. Among these, aromatic hydrocarbons are particularly preferable because they are liquid at room temperature and can be easily mixed and adjusted in advance with the fibrous carbonization catalyst. The hydrocarbon feed rate is preferably 5 to 100 m / s.

  As the fibrous carbonization catalyst and the cocatalyst, fine particles such as Co, Ni, Fe, Mo, S, V, and Cr can be used. In particular, organic substances such as ferrocene and thiophene are soluble in aromatic hydrocarbons such as benzene, so they are easy to handle, and because the elements contained in the compound are atomic in size, they effectively act as catalysts in the reaction field. Therefore, it is particularly preferable.

  The mixing ratio of the hydrocarbon, the catalyst and the cocatalyst when producing fibrous carbon in the carbon black composite of the present invention is preferably 80:20 to 99: 1, and particularly 90:10 to 95: 5, in mass ratio. preferable.

The carbon black in the carbon black composite of the present invention is preferably generated in a high temperature field equal to or higher than the thermal decomposition temperature of the hydrocarbon, and particularly preferably generated at 1800 to 2200 ° C. As hydrocarbons, for example, saturated hydrocarbons such as methane, ethane, propane, butane, etc., unsaturated hydrocarbons having double bonds such as ethylene, propylene, butene, butadiene, etc., and triple bonds such as acetylene, propyne, butyne, etc. Unsaturated hydrocarbons, aromatic hydrocarbons such as benzene, toluene and xylene can be used. Among these, ethylene, acetylene, and butadiene are preferable because they are self-exothermic decomposition reactions and can maintain high temperatures even in the central portion of the reaction furnace, and acetylene is particularly preferable. It is preferable that the supply amount of the hydrocarbon is 5 to 20 m ³ / h, it is particularly preferably 10 to 15 m ³ / h.

  It is preferable that the fibrous carbon in the carbon black composite of the present invention is fired by being introduced into the carbon black production field and composited to have a Raman intensity ratio (D / G value) of 0.30 or less. .

  EXAMPLES Next, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Examples 1-3)
Fibrous carbon was produced by the following method. Benzene (reagent manufactured by Kanto Chemical Co., 99%) as a carbon source, ferrocene (reagent manufactured by Kanto Chemical Co., 98%) as a catalyst, and thiophene (reagent manufactured by Kanto Chemical Co., 98%) as a co-catalyst in a mass ratio of 90: 8 : 2 gasified at 300 ° C. was sprayed with hydrogen gas from a nozzle installed above the vertical tubular furnace to produce fibrous carbon at a flow rate of 50 m / s and temperatures of 600, 800, 1000 ° C. The Raman intensity ratio (D / G value) at this time is shown in Table 1. Moreover, the diameter of the fibrous carbon at each temperature is shown in Table 1. Next, acetylene gas (purity 99%) was supplied at a flow rate of 10 m3 / h from one of the two nozzles installed at the top of the reactor (furnace length 6 m, furnace diameter 1 m) and pyrolyzed at 2000 ° C. Thus, carbon black was produced, and fibrous carbon produced at 600, 800, and 1000 ° C. was introduced from the other side so as to be 30% by mass, and composited. The carbon black composite was collected from a bag filter directly connected to the lower part of the furnace. The Raman intensity ratio (D / G value) of the fibrous carbon at this time is shown in Table 1. These were evaluated and the results are shown in Table 1.
(1) About the diameter of fibrous carbon, 100 pieces were measured with the transmission electron microscope (TEM) by the magnification of 30,000 times, and the average diameter was calculated | required.
(2) For the Raman intensity ratio measurement, the intrinsic peak G band and D band of carbon were measured at an excitation laser wavelength of 532 nm, an exposure time of 1.0 second, and an exposure frequency of 30 times.
(3) Ashes were measured according to JIS K 1469.
(4) The powder resistance was measured according to JIS K 1469.
(5) Conductivity Evaluation by Measuring Compound Volume Specific Resistance Value 10 parts by mass of the carbon black composites of Examples 1 to 3 and Comparative Example 1 are blended with 90 parts by mass of PS resin (trade name “H700” manufactured by Toyo Styrene Co., Ltd.). Then, the mixture was kneaded for 10 minutes using a kneader (manufactured by Toyo Seiki Seisakusho, trade name “Laboplast Mill”) at a blade rotation speed of 30 rpm and a temperature of 220 ° C. The kneaded product was heated to 200 ° C. and pressure-molded at a pressure of 9.8 × 10 ⁶ Pa to prepare a 2 × 2 × 70 mm test piece. A digital multimeter (Yokogawa Electric Corporation, trade name “Digital” Using a multimeter 7562 "), the volume resistivity was measured according to SRI2301.

  As Examples 4 and 5, fibrous carbon was produced by the production method described in Example 1 with the carbon source gas of fibrous carbon set to 5,100 m / s, and introduced into the acetylene gas reactor of Example 1 to obtain carbon black. A composite was produced. In Examples 6 and 7, fibrous carbon was produced by setting the carbon source gas of the fibrous carbon described in Example 1 to 3,120 m / s, and introduced into the acetylene gas reactor of Example 1 to obtain carbon black. A composite was produced.

  In Examples 8 and 9, the content of fibrous carbon was 10% and 50% in the production method described in Example 1, and in Examples 10 and 11, the content of fibrous carbon was 5 in the production method described in Example 1. % And 60% were introduced into the fibrous carbon.

  For Comparative Example 1, fibrous carbon and carbon black were produced separately by the method described in Example 1, and mixed at 200 rpm and 60 min in a ball mill at a mass ratio of 30:70, respectively, to produce a carbon black composite. did.

  For Comparative Example 2, acetylene gas was supplied at 15 m 3 / h from a nozzle installed above a reactor (furnace length 6 m, furnace diameter 1 m) based on WO / 2007/013678, and acetylene gas was heated at 2000 ° C. While producing carbon black by decomposition, benzene (Kanto Chemicals reagent, 99%, 3.7 kg / h) from the upper portion of 1000 ° C. and ferrocene as a catalyst (Kanto Chemicals reagent, 98%, 0) .3 kg / h), and a mixed gas of thiophene (reagent manufactured by Kanto Chemical Co., 98%, 0.05 kg / h) is supplied as a co-catalyst to produce fibrous carbon, so that the fibrous carbon becomes 30% by mass. A carbon black composite was produced.

  From Table 1, the carbon black composites obtained by Examples or Reference Examples of the present invention have lower powder resistance and compound resistance than the carbon black composites obtained by Comparative Examples 1 and 2, and the conventional carbon. Excellent conductivity imparting effect than the black composite.

The carbon black composite of the present invention can be used as a conductive agent for batteries such as a primary battery, a secondary battery, a fuel cell, and a capacitor in addition to a conductivity imparting agent for resin and rubber.

Claims (3)

In the process of supplying acetylene gas at a flow rate of 10 m ³ / h and thermally decomposing at 2000 ° C. to produce acetylene black, benzene as a carbon source, ferrocene as a catalyst, and thiophene as a co-catalyst in a mass ratio of 90: 8: 2 As a fibrous carbon which is gasified at 300 ° C., introduced at 50 to 100 m / s, and added with fibrous carbon produced by heat treatment at a temperature of 600 to 1000 ° C., and the fibrous carbon and acetylene black are combined. The content rate is 30 to 50 % by mass, the Raman intensity ratio (D / G value) of fibrous carbon is 0.24 or less, and the ash content defined by JIS K 1469 is 0.01% by mass or less. Carbon black composite. In the process of supplying acetylene gas at a flow rate of 10 m ³ / h and thermally decomposing at 2000 ° C. to produce acetylene black, benzene as a carbon source, ferrocene as a catalyst, and thiophene as a co-catalyst in a mass ratio of 90: 8: 2 Gasified at 300 ° C., introduced at 50 to 100 m / s, and added with fibrous carbon produced by heat treatment at a temperature of 600 to 1000 ° C., and the fibrous carbon and acetylene black are combined, Carbon having a fibrous carbon content of 30-50% by mass, a fibrous carbon Raman intensity ratio (D / G value) of 0.24 or less, and an ash content defined by JIS K 1469 of 0.01% by mass or less. A method for producing a black composite. The method for producing a carbon black composite according to claim 2, wherein the diameter of the fibrous carbon is 90 nm or less.