Carbon black and methods of carbon black production.

Abstract

DEPCT66 Carbon black has a specific surface area for nitrogen adsorption (N2SA) of 25-60 sq.m. m³ / g, the absorption rate of DBP is 90-180 cubic centimeters / 100 grams, the ratio of... The specific surface area for nitrogen adsorption (N2SA) to iodine adsorption (lA) ratio (N2SA / lA) is equal to: 1.10x10³ - 1.50x10³ square meters / gram, NMR hydrogen content equals 150-250 / gram, Delta D. Equivalent to 260-290 centimeters per second. -----------------------------------------------------------

Description

Carbon black and method for producing carbon black

[0001] The present invention relates to carbon black and a method for producing the same.

[0002] Carbon black is used in a variety of applications, primarily as a filler for reinforcing rubber components. It is known that uniform dispersion of carbon black throughout a rubber component is important for providing sufficient reinforcing properties to the rubber component.

[0003] Various technical improvements have been made to improve the dispersibility of carbon black and enhance the reinforcing properties of rubber components. For example, Patent Document 1 discloses carbon black that has good dispersibility in rubber mixtures, a very high reinforcing effect, and little hysteresis. According to the invention described in Patent Document 1, the above-mentioned problems can be solved by using carbon black whose CTAB surface area, COAN, and the sum of OAN and COAN fall within predetermined numerical ranges.

[0004] Patent No. 6140915

[0005] In recent years, rubber parts have increasingly been used in harsh environments. As a result, there is a demand for carbon black with improved reinforcing properties for rubber parts. Therefore, an object of the present invention is to provide carbon black that can further reinforce rubber parts when blended with rubber parts, and a method for producing the same.

[0006] The inventors measured the nitrogen adsorption specific surface area (hereinafter referred to as NSA) of carbon black, the DBP absorption amount, the ratio of NSA to the iodine adsorption amount (hereinafter referred to as IA) (hereinafter referred to as NSA / IA), the amount of hydrogen ( / g), and the full width at half maximum ΔD (cm -1 It has been found that the above-mentioned problems can be solved by restricting the values ​​of each of these factors to within a specific range. That is, the present invention includes the following: [1] Nitrogen adsorption specific surface area (NSA) is 25 to 60 m 2 / g, and the DBP absorption is 90 to 180 cm 3 / 100g, and the ratio (N2SA / IA) of the nitrogen adsorption specific surface area (N2SA) to the iodine adsorption amount (IA) was 1.10 × 10 3 ~1.50 x 10 3 m 2 / g, and when the nuclear magnetic resonance signal of the spin-spin relaxation process observed by the solid echo method is expressed as the sum of a first signal and a second signal having a larger time constant than the first signal, the amount of hydrogen expressed by the signal intensity per unit mass of the first signal at time 0 is 150 to 250 / g, and when the excitation wavelength is 532 nm, it is 1340 to 1360 cm -1 The full width at half maximum ΔD of the Raman scattering peak that appears in the range of 260 to 290 cm -1 [2] Carbon black having a DBP absorption of 90 to 150 cm 3 [3] The carbon black according to [1], wherein the NSA / IA is 1.20 × 10 3 ~1.50 x 10 3 m 2 / g. [4] The carbon black according to any one of [1] to [3], which is used as a filler for rubber members. [5] The carbon black according to [4], which is added in an amount of 10 to 170 parts by mass per 100 parts by mass of the rubber component in the rubber member. [6] A method for producing carbon black, comprising: a reaction step in which hydrocarbons as a raw material are incompletely combusted in a reactor to produce a carbon black raw material; a granulation step in which the carbon black raw material is granulated to particles of a predetermined size; and a drying step in which the granulated carbon black raw material is dehydrated and dried, wherein the reaction step is carried out in a reaction zone between a position for introducing a refrigerant and a position for introducing a cooling liquid in the reactor, the refrigerant is introduced so that the temperature in the reaction zone is 800 to 900°C, and the cooling liquid is introduced so that the residence time of the carbon black raw material in the reaction zone is 20 to 30 msec, thereby terminating the reaction of the carbon black raw material.

[0007] According to the present invention, there are provided carbon black and a method for producing the same, which, when compounded in a rubber component, can increase the tensile product of the rubber compared to conventional methods.

[0008] Fig. 1 is a diagram for explaining a method for calculating the amount of hydrogen. Fig. 2 is a diagram for explaining a method for calculating the amount of hydrogen. Fig. 3 is a diagram showing a method for calculating the full width at half maximum ΔD of a Raman scattering peak. Fig. 4 is a block diagram showing the sequence of processing steps for producing carbon black. Fig. 5 is a schematic diagram showing an example of a reactor.

[0009] An embodiment of the present invention will be described below.

[0010] The carbon black according to this embodiment is used as a filler added to rubber members. The carbon black according to this embodiment is used to reinforce the rubber members. In the following, "reinforcing" a rubber member means increasing the product of the tensile strength and tensile elongation of the rubber member, i.e., the tensile product of the rubber member.

[0011] Generally, in order to enhance the reinforcing properties of carbon black for rubber components, a high surface activity of carbon black increases the ease of interaction with rubber, which is expected to enhance the reinforcing properties of rubber components. However, in reality, increasing the surface activity of carbon black makes it more likely for carbon black particles to homo-aggregate, making it difficult to uniformly disperse the carbon black. As a result, the reinforcing effect of carbon black is not fully achieved. Therefore, the present inventors focused on the "hydrogen content" and "crystallinity" of carbon black. These properties affect the ease of interaction with rubber and the aggregation tendency of carbon black. Therefore, it was thought that by restricting these properties within a predetermined range, it would be possible to simultaneously improve the ease of interaction and high dispersibility. In addition, the present inventors focused on both macro-dispersibility and micro-dispersibility with regard to dispersibility. They then adjusted the values ​​of "hydrogen content" and "crystallinity" to obtain good dispersibility at both the macro- and micro-scales. As a result, they found that carbon black with high surface activity and excellent dispersibility could be obtained, thereby further reinforcing rubber components.

[0012] Specifically, the carbon black according to this embodiment has the following characteristics: (A) a nitrogen adsorption specific surface area (NSA) of 25 to 60 m 2 (B) DBP absorption is 90 to 180 cm 3 (C) The ratio (N2SA / IA) of the nitrogen adsorption specific surface area (N2SA) to the iodine adsorption amount (IA) is 1.10 × 10 3 ~1.50 x 10 3 m 2 (D) When the nuclear magnetic resonance signal of the spin-spin relaxation process observed by the solid echo method is expressed as the sum of a first signal and a second signal having a larger time constant than the first signal, the amount of hydrogen expressed as the signal intensity per unit mass of the first signal at time 0 is 150 to 250 ( / g). (E) When the excitation wavelength is 532 nm, the amount of hydrogen is 1340 to 1360 cm -1The full width at half maximum ΔD value of the Raman scattering peak appearing in the range of 260 to 290 cm -1 is.

[0013] The carbon black according to the present embodiment has the above properties, and therefore when added as a filler to a rubber member, it disperses well both microscopically and macroscopically, thereby improving the tensile product of the rubber member.

[0014] The specific features of the carbon black according to this embodiment will be described in detail below.

[0015] (A) N2SA: 25-60m 2 / g NSA is the specific surface area of ​​carbon black expressed as the amount of nitrogen molecules adsorbed per unit mass of carbon black (m 2 The N2SA is a value expressed in units of 1 / g. The N2SA can be determined by the method described in JIS K6217-7:2013 "Test method for basic performance of carbon black for rubber" (reference ASTM D6556-16). 2 / g. 2 / g or more, high reinforcing properties can be obtained. 2 / g or less, homo-agglomeration of carbon black particles can be suppressed, and high dispersibility can be obtained. 2 / g~55m 2 / g.

[0016] (B) DBP absorption: 90-180 cm 3 / 100g DBP absorption is the amount of DBP (dibutyl phthalate) absorbed per 100g of carbon black (cm 3The DBP absorption is a value expressed in units of 1 / 100g. The DPB absorption can be determined in accordance with JIS K6217-1997 "Testing methods for the basic performance of carbon black for rubber". The void ratio between carbon black aggregates is positively correlated with the structure of the carbon black. Therefore, the larger the DBP absorption value, the more developed the carbon black structure is. The DBP absorption is measured in the range of 90 to 180 cm. 3 / 100g. DBP absorption is preferably 90 cm 3 / 100g or more, high dispersibility can be obtained. 3 From the viewpoint of obtaining good processability and high reinforcing properties, the DBP absorption is more preferably 150 cm 3 / 100g or less.

[0017] Furthermore, as long as it provides a means for solving the problems that the present invention aims to solve, the present invention can also be practiced by restricting the numerical ranges of N2SA and DBP absorption to predetermined values, as follows. For example, by setting the N2SA of the carbon black slightly higher than the center of the above-mentioned more preferred range, the interaction between the carbon black and rubber can be increased, and by setting the DBP absorption of the carbon black slightly lower than the center of the above-mentioned preferred range, the tensile product of the rubber component when added to rubber can be increased, thereby imparting greater reinforcing properties to the rubber component. In this case, the N2SA is 49m 2 / g or more 55m 2 / g or less, and the DBP absorption is 115 cm 3 / 100g or more 135cm 3It is preferable to set the N2SA of the carbon black near the center of the above-mentioned more preferable range to suppress homo-aggregation of carbon black particles, and by setting the DBP absorption of the carbon black slightly lower than the center of the above-mentioned preferable range, the tensile product of the rubber material when added to rubber can be increased, thereby achieving both good dispersibility in rubber and high reinforcing properties. In this case, the N2SA is set to 35 m 2 / g or more 47m 2 / g or less, and the DBP absorption is 115 cm 3 / 100g or more 132cm 3 It is preferable to set the N2SA of the carbon black to a value slightly lower than the center of the more preferable range, thereby strongly suppressing homo-aggregation of carbon black particles, and by setting the DBP absorption of the carbon black to a value slightly higher than the center of the more preferable range, a large shear force can be obtained when the carbon black is added to rubber and kneaded, thereby achieving better dispersibility in the rubber. In this case, the N2SA is set to 28 m 2 / g or more 34m 2 / g or less, and the DBP absorption is 133 cm 3 / 100g or more 141cm 3 It is preferable to set it in the range of 100g or less.

[0018] (C) N2SA / IA: 1.10×10 3 ~1.50 x 10 3 m 2 / g IA is a value that expresses the specific surface area of ​​carbon black as the amount of iodine molecules adsorbed per unit mass of carbon black in the liquid phase (mg / g). Like N2SA, IA is an index that represents the specific surface area of ​​carbon black, but IA is a value that also depends on the amount of surface functional groups on the carbon black (the greater the amount of acidic functional groups, the more difficult it is for iodine molecules to be adsorbed, resulting in a value slightly lower than N2SA). IA can be determined in accordance with JIS K6217-1997, "Test methods for basic performance of carbon black for rubber."

[0019] The value obtained by dividing the N2SA value by the IA value is an index representing the surface activity of carbon black. Here, the N2SA / IA value is expressed in m 2 It is calculated by setting the unit of N2SA / IA to mg / g and the unit of IA to mg / g. The larger the N2SA / IA value, the greater the amount of surface functional groups in the carbon black. When the amount of surface functional groups in the carbon black is large, chemical reactions tend to occur on the surface of the carbon black via the surface functional groups, making it easier for the carbon black to interact with rubber. In other words, the surface activity value of carbon black quantitatively indicates the likelihood of chemical reactions occurring on the surface of the carbon black.

[0020] According to this embodiment, NSA / IA is 1.10 × 10 3 m 2 / g or more, reinforcement can be obtained. 3 m 2 / g or less, production is easy. As will be described in detail later, carbon black is produced, for example, by burning raw oil to obtain raw carbon black particles, which are then granulated. Here, shortening the combustion reaction time makes it possible to increase N2SA / IA. However, if the combustion reaction time is too short, unburned oil tends to remain, making granulation difficult. When N2SA / IA is 1.50 × 10 3 m 2 If the NSA / IA is 1.20 × 10 / g or less, the reaction can be carried out under conditions in which unburned oil is less likely to remain during production. 3 m 2 / g or more is preferred.

[0021] (D) Hydrogen Amount: 150 to 250 / g The hydrogen amount refers to the amount of hydrogen determined by NMR. The higher this value, the greater the amount of hydrogen present on the surface of the carbon black. The inventors believed that the amount of hydrogen present on the surface of the carbon black is related to the ease of interaction with rubber and the cohesion of the carbon black, thereby affecting its reinforcing and dispersibility. A high amount of hydrogen present on the surface increases the ease of interaction between the carbon black and rubber, i.e., cohesion (heterocohesion) between the carbon black and rubber occurs more easily, improving dispersibility and resulting in improved reinforcing properties. On the other hand, if the amount of hydrogen present on the surface is too high, cohesion (homocohesion) between the carbon blacks occurs more easily, reducing dispersibility and resulting in reduced reinforcing properties. With these factors in mind, the NMR hydrogen amount was investigated and a range of 150 to 250 was determined. The hydrogen amount is preferably 150 to 240 / g from the viewpoint of further facilitating interaction with rubber and achieving good dispersibility.

[0022] Specifically, the amount of hydrogen can be determined by the following method: (1) Using a Bruker Biospin Minispec mq20 as a pulsed nuclear magnetic resonance spectrometer, carbon black to be measured is dried at 110°C for 30 minutes, and 0.2 g of the carbon black is filled into a glass sample tube to serve as a measurement sample. The spin-spin relaxation time (transverse relaxation time) T2 is measured under the following measurement conditions to obtain a T2 relaxation curve (free induction decay curve). <Measurement conditions> Measurement nuclide: 1H Pulse mode: solid echo method (90°×-τ-90°y) 90° pulse width: 2.7 μs Measurement time: 2 ms Waiting time: 500 ms Number of accumulations: 52 Measurement temperature: 40°C Gain: 90 Since the mass of the carbon black is constant at 0.2 g and the instrument function is also constant (Gainn = 90), the signal intensity of the resulting T2 relaxation curve (free induction decay curve) increases or decreases in proportion to the 1H concentration of the object to be measured.

[0023] (2) The obtained free induction decay curve is fitted by the linear least squares method using fitting software (TD-NMR-A for Windows 7) attached to the pulsed nuclear magnetic resonance apparatus (Bruker BioSpin Minispec mq20) to obtain an approximate curve represented by the following equation f(t): f(t) = A(1)exp(-t / T2(1)) + A(2)exp(-t / T2(2)) (where T2(1) is the relaxation time of the component with a short relaxation time, T2(2) is the relaxation time of the component with a long relaxation time, A(1) is the signal intensity at t = 0 of the component with a short relaxation time, and A(2) is the signal intensity at t = 0 of the component with a long relaxation time). (3) The signal intensity A(1) is divided by the mass w (g) of the measurement sample. As shown in FIG. 1 , when the time of excitation with a 90° pulse is set to t = 0, a signal is obtained in which the magnetization (signal intensity) in the y-axis direction decays over time. It should be noted that the graph in FIG. 1 is shown for the purpose of explaining the method for calculating the NMR hydrogen content and does not represent the measurement results of the carbon black according to this embodiment. FIG. 2 shows, with a solid line, a fitting curve obtained by fitting the T2 relaxation curve (free induction decay curve) shown in FIG. 1 using the linear least squares method. As shown in FIG. 2 , the resulting T2 relaxation curve (free induction decay curve) can be expressed as the sum of two exponential functions through fitting. Here, since liquids and solids can be distinguished based on the difference in time constants, the signal intensity A(1) at t = 0 (when excited with a 90° pulse) in the exponential function for the component with a short relaxation time can be identified as hydrogen atoms (-COOH, -OH, -H on the surface, -H in the carbon skeleton, etc.) on the carbon black surface. Similarly, in the exponential function for the component with a short relaxation time, the signal intensity A(2) at t = 0 (when excited by a 90° pulse) can be identified as moisture adsorbed on the carbon black surface, liquid polycyclic aromatic hydrocarbon compounds, etc. The amount of hydrogen per unit mass of carbon black, "A(1) / w," can be calculated by dividing the signal intensity A(1) (a.u.) by the mass w (0.2 g) of the carbon black used in the measurement. Here, the standard carbon black used in this measurement is Seast 9 (trade name) manufactured by Tokai Carbon Co., Ltd., and its hydrogen amount is 114 / g.That is, the amount of hydrogen in the sample to be measured is determined by adjusting the measurement conditions that affect the signal intensity so that the hydrogen amount in SEAST 9 (product name) manufactured by Tokai Carbon Co., Ltd. is 114 / g. According to the investigations of the present inventors, it has been found that the amount of hydrogen expressed as A(1) / w shows a high correlation with the amount of hydrogen obtained by the pyrolysis method, which has been conventionally known as a method for measuring the amount of hydrogen on the surface of carbon black. For this reason, it can be suitably used as an index representing the amount of hydrogen on the surface of carbon black.

[0024] (E) Full width at half maximum of Raman scattering peak ΔD: 260 to 290 cm -1 ΔD is a Raman spectrum obtained when measured at an excitation wavelength of 532 nm using a laser Raman spectrometer, and the -1 The full width at half maximum (cm) of the peak having a peak top in the range -1 In the Raman spectrum, 1350±10 cm -1A peak having a peak top in this range corresponds to a peak in the D band of a Raman spectrum. According to the inventors' studies, the full width at half maximum of the D band peak represents the degree of disorder in the crystalline structure on the carbon black surface, i.e., crystallinity. A larger ΔD value means a more disordered crystalline structure (lower crystallinity). When the crystalline structure is disordered (low crystallinity), there are many edges on the carbon black surface, i.e., many active sites where functional groups that exhibit affinity for rubber can form, improving the ease of carbon black interaction with rubber. As a result, hetero-aggregation between carbon black and rubber is more likely, improving dispersibility. On the other hand, if the crystallinity is too low, homo-aggregation between carbon blacks is more likely to occur, which in turn impairs dispersibility. Taking these factors into consideration, studies were conducted to obtain optimal crystallinity, resulting in a ΔD of 260 to 290. In other words, a ΔD value of 260 or more makes hetero-aggregation more likely, resulting in high dispersibility and, as a result, improved reinforcement. Furthermore, when the ΔD value is 290 or less, homo-aggregation is less likely to occur, high dispersibility is obtained, and high reinforcing properties are also obtained. From the viewpoint of obtaining easy interaction with rubber and good dispersibility, the ΔD value is 260 to 280 cm -1 It is more preferable that:

[0025] Specifically, ΔD can be measured by the following method. FIG. 3 is a diagram showing a method for calculating the value of ΔD. Note that FIG. 3 is shown only to explain the method for calculating ΔD, and does not represent the measurement results of the carbon black according to this embodiment. As shown in FIG. 3, in the Raman spectrum obtained by measuring carbon black by laser Raman spectroscopy at an excitation wavelength of 532 nm, a peak of 1350±10 cm -1 A peak having a peak top in the range of Dmax (cm -1 ) and in the obtained ΔD spectrum, the detection position on the low wavelength (low Raman shift) side having a detection intensity half the peak intensity at Dmax is defined as D50 (cm -1), the value calculated by the following formula is ΔD (cm -1 ) ΔD value = (Dmax - D50) x 2 Here, the carbon black used as the standard for this measurement is Seast G-SO (trade name) manufactured by Tokai Carbon Co., Ltd., and its ΔD value is 249 cm -1 That is, the ΔD of the measurement sample is 249 cm for Seast 9 (product name) manufactured by Tokai Carbon Co., Ltd. -1 The measurement conditions that affect the ΔD value are adjusted so that the ΔD value is obtained.

[0026] (F) Other Specific Matters The carbon black according to this embodiment is used as a filler for reinforcing a rubber member, as described above. The rubber member is not particularly limited, and may be, for example, a general-purpose rubber such as natural rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, acrylonitrile-butadiene rubber, or chloroprene rubber; a special rubber such as acrylic rubber, chlorosulfonated polyethylene rubber, urethane rubber, silicone rubber, or fluororubber; or a rubber member made of a mixture of these. Preferred applications of rubber components using the carbon black according to this embodiment as a filler include various rubber components for automobiles and other general industries, such as weatherstrips, hoses, belts, vibration-proof and vibration-damping rubber, boots, and seals / packing materials. As automobiles continue to improve in performance, rubber components are increasingly used in harsh environments, such as high temperatures and high pressures. Furthermore, the miniaturization of rubber components due to the compactness of automobile units is also progressing, and the thinning of rubber components due to the weight reduction of automobile units is also progressing. As a result, it is becoming increasingly difficult for conventional carbon black to satisfactorily impart the reinforcing properties required for rubber components. The carbon black according to this embodiment is useful in meeting these requirements for automotive rubber components. The carbon black is preferably blended in an amount of, for example, 10 to 170 parts by mass, and preferably 20 to 160 parts by mass, per 100 parts by mass of the rubber component.

[0027] (G) Method for Producing Carbon Black The carbon black according to this embodiment can be obtained by incompletely combusting a hydrocarbon raw material and appropriately adjusting the reaction conditions according to a general method for producing carbon black, such as an oil furnace method. An example of the method for producing the carbon black according to this embodiment is described below.

[0028] Fig. 4 is a block diagram showing the sequence of processing steps for producing carbon black, which is one embodiment of the present invention. Fig. 5 is a schematic diagram showing an example of a reactor. Carbon black, which is one embodiment of the present invention, can be produced by sequentially performing a reaction step S1, a granulation step S2, and a drying step S3 in this order, as shown in Fig. 4. First, in the reaction step S1, a carbon black raw material is produced in a reactor 10. As shown in Fig. 5, the reactor 10 is cylindrical and includes a fuel combustion zone 4, a raw material introduction zone 6, and a reaction zone 9.

[0029] The fuel combustion zone 4 is a section where high-temperature combustion gas is generated. The fuel combustion zone 4 is provided with an oxygen-containing gas inlet 1, a combustion burner 2, and an alkali metal salt / aqueous solution supply nozzle 3. An oxygen-containing gas (oxygen, air, etc.) is introduced into the fuel combustion zone 4 from the oxygen-containing gas inlet 1. Furthermore, a fuel (FCC residual oil, hydrogen, carbon monoxide, natural gas, petroleum gas, etc.) is supplied to the fuel combustion zone 4 from the combustion burner 2. This generates high-temperature combustion gas. An alkali metal salt / aqueous solution, such as carbonates, chlorides, hydroxides, etc. of sodium, potassium, etc., is supplied to the fuel combustion zone 4 from the alkali metal salt / aqueous solution supply nozzle 3. Addition of the alkali metal salt / aqueous solution can be adjusted to prevent the development of carbon black structure in the raw material introduction zone 6. The combustion gas generated in the fuel combustion zone 4 is supplied to the raw material introduction zone 6.

[0030] The feedstock introduction zone 6 is a section where feedstock oil is introduced. The diameter of the feedstock introduction zone 6 is smaller than that of the fuel combustion zone 4. A feedstock introduction nozzle 5 is connected to the feedstock introduction zone 6. The feedstock oil is introduced into the feedstock introduction zone 6 through the feedstock introduction nozzle 5 and mixed with the combustion gas. During this process, minute carbon black nuclei are generated by thermal decomposition, and collisions between the nuclei form a predetermined structure, producing carbon black fine particles, which are the raw material for carbon black. Examples of feedstock oil include aromatic hydrocarbons such as naphthalene and anthracene, coal-based hydrocarbons such as creosote oil and tar oil, petroleum-based heavy oils such as FCC residual oil and ethylene heavy end oil, acetylenic unsaturated hydrocarbons, and aliphatic hydrocarbons such as hexane. The mixture of combustion gas and feedstock oil is supplied to the reaction zone 9.

[0031] The reaction zone 9 is a zone where the carbon black particles produced in the raw material introduction zone 6 are further grown in the vapor phase and then the reaction is terminated. The diameter of the reaction zone 9 is larger than the diameter of the fuel combustion zone 4. The flow rate of the carbon black particles produced in the raw material introduction zone 6 is reduced in the wide-diameter reaction zone 9. At this time, aromatic hydrocarbons in the vapor phase carbonize and grow on the surface of the carbon black particles, producing carbon black raw material. The reaction zone 9 is provided with a refrigerant introduction nozzle 7 and a cooling liquid introduction nozzle 8 for terminating the reaction. The refrigerant introduction nozzle 7 is located upstream of the cooling liquid introduction nozzle 8. A refrigerant is supplied to the reaction zone 9 from the refrigerant introduction nozzle 7 to control the temperature of the reaction zone 9. Cooling water is sprayed into the reaction zone 9 from the cooling liquid introduction nozzle 8, thereby terminating the reaction for producing the carbon black raw material.

[0032] The carbon black raw material produced in the reaction zone 9 is transferred to a collection system (not shown) and collected by a collection device such as a cyclone or a bag filter.

[0033] Next, in the granulation step S2, the carbon black raw material is granulated so that the particles of the carbon black raw material have a predetermined size. The specific mode of this granulation process is not particularly limited, and any known granulation method can be applied. An example of a known granulation method is a wet granulation method. One example of a wet granulation method is a method in which a shaft having a plurality of special rod-shaped pins arranged in a spiral at the center of a cylinder is rotated at high speed in a predetermined container, and carbon and water are continuously supplied into the container and stirred and mixed to granulate them into pellets of a predetermined size.

[0034] Next, in the drying step S3, the granulated carbon black raw material is dried to remove water from the granulated carbon black raw material, thereby obtaining a dried carbon black raw material. The specific mode of this drying treatment is not particularly limited, and any known drying method can be applied. An example of a known drying method is an indirect heating drying method. One example of an indirect heating drying method is one that uses an indirect heating rotary dryer. This method involves supplying hot gas into the space between the outer and inner cylinders of a rotary kiln-like double-tube structure provided in the indirect heating rotary dryer, and heating and drying the moist granulated carbon black raw material placed in the inner cylinder at a predetermined temperature.

[0035] Carbon black is produced through the steps described above. Here, the properties of the resulting carbon black can be controlled by adjusting the reaction conditions in reaction step S1, for example. For example, increasing the amount of alkali metal salt / aqueous solution introduced in reaction step S1 reduces the DBP absorption. Therefore, adjusting the amount of alkali metal salt / aqueous solution introduced can achieve a desired DBP absorption. Furthermore, increasing the amount of oxygen-containing gas introduced or decreasing the amount of feedstock oil introduced in reaction step S1 increases the NSA value. Therefore, adjusting the amount of oxygen gas introduced or the amount of feedstock oil introduced can achieve a desired NSA. Furthermore, shortening the reaction time from the introduction of the feedstock oil to quenching to terminate the reaction increases the NSA / IA value. Therefore, adjusting this reaction time can achieve a desired NSA / IA. Furthermore, the NMR hydrogen content and ΔD (crystallinity) depend on the reaction temperature and residence time in reaction zone 9. Therefore, a coolant such as an inert gas such as nitrogen, heavy oil having a specific gravity of less than 1.0 (heavy oil A, heavy oil B, or heavy oil C), light hydrocarbon (gasoline, diesel, kerosene, or the like), or water vapor is introduced into reaction zone 9 (furnace temperature 1000°C or higher) between raw material introduction region 6 and coolant introduction nozzle 8 in FIG. 1 through coolant introduction nozzle 7, while adjusting the amount added so that the reaction temperature in reaction zone 9 is 800 to 900°C. Furthermore, the reaction is stopped by quenching (rapid cooling by water spray) so that the residence time (between nozzles 7 and 8) is 20 to 30 msec, thereby obtaining the desired NMR hydrogen amount and ΔD.

[0036] EXAMPLES In the following, examples will be described in more detail to explain the present invention, but the present invention should not be construed as being limited to the following examples.

[0037] (Examples 1 to 12, Comparative Examples 1 to 10) Carbon black according to one embodiment of the present invention was produced according to the processing sequence shown in FIG. 4 . First, in the reaction step S1, a reactor having the configuration shown in FIG. 5 was used, and the presence or absence of refrigerant introduction into the reaction zone 9 through the refrigerant introduction nozzle 7, the reaction temperature in the reaction zone 9, and the residence time until the reaction was stopped were all varied to produce carbon black raw materials with different properties. (Examples 1 to 12) Nitrogen was introduced through the refrigerant introduction nozzle 7 into the reaction zone 9 between the feedstock oil introduction nozzle 5 and the coolant introduction nozzle 8, and the reaction temperature was adjusted to 800 to 900°C, and the residence time until the reaction was stopped through the coolant introduction nozzle 8 was adjusted to 20 to 30 msec. (Comparative Example 1) Nitrogen was introduced through the refrigerant introduction nozzle 7 into the reaction zone 9 between the feedstock oil introduction nozzle 5 and the coolant introduction nozzle 8, and the reaction temperature was adjusted to 800 to 900°C, and the residence time until the reaction was stopped through the coolant introduction nozzle 8 was adjusted to less than 20 msec. (Comparative Examples 2, 3, 7 to 9) Production was performed without introducing nitrogen into the reaction zone 9 through the coolant introduction nozzle 7. (Comparative Example 4) Nitrogen was introduced into the reaction zone 9 between the feed oil introduction nozzle 5 and the coolant introduction nozzle 8 through the coolant introduction nozzle 7, and production was performed by adjusting the reaction temperature to less than 800°C and the residence time until the reaction was stopped by the coolant introduction nozzle 8 to 20 to 30 msec. (Comparative Example 5) Nitrogen was introduced into the reaction zone 9 between the feed oil introduction nozzle 5 and the coolant introduction nozzle 8 through the coolant introduction nozzle 7, and production was performed by adjusting the reaction temperature to more than 900°C and the residence time until the reaction was stopped by the coolant introduction nozzle 8 to 20 to 30 msec. (Comparative Example 6) Nitrogen was introduced into the reaction zone 9 between the feed oil introduction nozzle 5 and the coolant introduction nozzle 8 through the coolant introduction nozzle 7, and production was performed by adjusting the reaction temperature to 800 to 900°C and the residence time until the reaction was stopped by the coolant introduction nozzle 8 to more than 30 msec. (Comparative Example 10) Nitrogen was introduced from a coolant introduction nozzle 7 into the reaction zone 9 between the feed oil introduction nozzle 5 and the coolant introduction nozzle 8, and the reaction temperature was adjusted to 800 to 900°C, and the residence time until the reaction was stopped by the coolant introduction nozzle 8 was adjusted to 20 to 30 msec. The nitrogen adsorption specific surface area (NSA) was adjusted to 60 m by adjusting the reduction in the amount of feed hydrocarbon. 2Carbon black exceeding 1 / g was produced. Next, in the granulation step S2, each of the carbon black raw materials obtained in the reaction step S1 was subjected to a wet granulation treatment under certain conditions. This resulted in the production of carbon blacks according to Examples 1 to 12 and Comparative Examples 1 to 10.

[0038] For each of the obtained Examples 1 to 12 and Comparative Examples 1 to 10, the presence or absence of nitrogen introduction through the coolant introduction nozzle 7, the temperature of the reaction zone 9 at the midpoint between the coolant introduction nozzle 7 and the cooling water introduction nozzle 8, the residence time at the midpoint between the coolant introduction nozzle 7 and the cooling water introduction nozzle 8, NSA, NSA / IA, DPB absorption amount, NMR hydrogen amount, and ΔD were measured. The results are shown in Tables 1-1, 1-2, and 2.

[0039] Next, 40 parts by mass of carbon black according to each Example and Comparative Example was added to 100 parts by mass of NBR rubber to prepare rubber compositions. The physical properties of the prepared rubber compositions were measured. The measured physical properties and measurement methods are as follows.

[0040] (Durometer Hardness Hs) The hardness Hs was measured using a type A durometer in accordance with JIS K6253-3-2012 (vulcanized rubber and thermoplastic rubber - Determination of hardness).

[0041] (Tensile strength TB) The tensile strength TB (MPa) at break was measured according to JIS K6251-2017 (vulcanized rubber and thermoplastic rubber - Determination of tensile properties).

[0042] (Elongation EB) The elongation EB (%) at break was measured according to JIS K6251-2017 (vulcanized rubber and thermoplastic rubber - Determination of tensile properties).

[0043] (Expansion Product TB×EB) Based on the TB and EB determined as above, the expansion product (TB×EB) was calculated.

[0044] (Payne Effect Value) Using a viscoelasticity spectrometer VR-7110 (manufactured by Ueshima Seisakusho Co., Ltd.), the dynamic modulus of elasticity at a strain of 0.1% (E'(0.1)) was measured under conditions of 50 Hz and 60°C. The dynamic modulus of elasticity at a strain of 2.0% (E'(2.0)) was also measured. The difference between the two (E'(0.1)-E'(2.0)) was calculated as the Payne effect value. In the dynamic viscoelasticity of rubber containing carbon black, the dynamic modulus in the low strain region is highly dependent on the cohesion of the carbon black particles, while the dynamic modulus in the high strain region is less dependent on the cohesion of the carbon black particles because the carbon black particles are pulled apart by a forcible external force when the rubber is elongated, and is therefore more dependent on the dynamic modulus of the rubber itself in a state where no carbon black is compounded. Therefore, the smaller the difference in dynamic modulus between the low strain region and the high strain region (Payne effect), the lower the cohesion of carbon black particles in the microscopic region of the rubber; in other words, the higher the dispersibility of carbon black in the microscopic region.

[0045] (Dispersion Ratio) The area occupied by undispersed carbon black agglomerates of 3 μm or more in size within a fixed field of view was measured in accordance with ASTM D7723 using a disperGRADER α view SR manufactured by Alpha Technologies, Inc. This dispersion ratio (%) is different from the Payne effect value and indicates the dispersibility of carbon black in the macroscopic region, with a smaller value indicating higher dispersibility in the macroscopic region.

[0046] (Study) The results are shown in Tables 1-1, 1-2 and 2.

[0047] In Examples 1 to 12, the nitrogen adsorption specific surface area (NSA), NSA / IA, DBP absorption, NMR hydrogen content, and ΔD were within the specified ranges. On the other hand, in Comparative Examples 1 to 10, the manufacturing conditions and / or at least one of the above properties were outside the specified ranges. Examples 1 to 12 had a larger tensile product (TB x EB) than Comparative Examples 1 to 10. This indicates that the rubber members containing the carbon black of Examples 1 to 12 are easily stretched and have high strength. Furthermore, Examples 1 to 12 had a lower Payne effect and a higher dispersion rate than Comparative Examples 1 to 10. This suggests that the carbon black of Examples 1 to 12 has high dispersibility not only in the macroscopic domain but also in the microscopic domain, resulting in high reinforcing properties.

[0048] From the above, it has been found that by setting the nitrogen adsorption specific surface area (NSA), DBP absorption amount, NSA / IA, NMR hydrogen amount, and ΔD within specific ranges, it is possible to obtain carbon black that is excellent in dispersibility not only in the macroscopic region but also in the microscopic region, and as a result, it is possible to significantly improve the tensile product of rubber members compared to conventional methods.

[0049]

[0050] REFERENCE SIGNS LIST 1 Oxygen-containing gas inlet 2 Combustion burner 3 Alkali metal salt / aqueous solution supply nozzle 4 Fuel combustion zone 5 Feedstock oil introduction nozzle 6 Feedstock introduction zone 7 Coolant introduction nozzle 8 Coolant introduction nozzle 9 Reaction zone 10 Reactor

Claims

DEPCT661. Carbon black with a specific surface area for nitrogen adsorption (N2SA) of 25-60 m³ / g, an adsorption volume (DBP) of 90-180 cm³ / 100g, and a ratio of nitrogen adsorption (N2SA) to iodine adsorption (lA) (N2SA / lA) of 1.10 x 10³ - 1.50 x 10³ m³ / g, when the nuclear magnetic resonance signal of the spin relaxation process observed by the solid echo method is expressed as the sum of the first and second signals with a time constant greater than that of the first signal, the amount of hydro... Gen is expressed as the signal intensity per unit mass at time 0 of the first signal, which is equal to 150-250 / g, the delta D value, the full width of the half-maximum Raman scattering peak which occurs in the range of 1340-1360 per centimeter when the wavelength for excitation is 532 nm, equal to 260-290 per centimeter.

2. Carbon black specified in claim 1, in which the absorption amount of such DBP is equal to 90-150 cubic centimeters / 100 grams.

3. Carbon black specified in claim 1 or 2, in which the N2SA / lA is equal to 1.20 x 10³ - 1.50 x 10³ m² / gram. 4.

5. Carbon black specified in any of the claims 1-3, which is used as a filler in rubber parts.

6. Carbon black specified in claim 4, which is added in an amount of 10-170 parts by mass per 100 parts by mass of the rubber component in such rubber parts.

7. A method of producing carbon black which includes a reaction step of incomplete combustion of the hydrocarbon raw material in a reactor to produce carbon black raw material, a pelletizing step of the carbon black raw material particles to a specified particle size, a drying step which removes water and dries the pelletized carbon black raw material, and a reaction step carried out in the reaction zone between the coolant inlet and coolant outlet positions in the reactor. Coolant is introduced to bring the temperature in this reaction zone to 800-900 degrees Celsius, the retention time of the carbon black raw material in this reaction zone is 20-30 milliseconds, and coolant is introduced to stop the reaction of the carbon black raw material.